Carbon Compounds, Inorganic
Doping in Sports
Oceans and Seas
Gas Chromatography-Mass Spectrometry
Carbon Monoxide Poisoning
Radioisotope Dilution Technique
Carbon Tetrachloride Poisoning
Indicator Dilution Techniques
Magnetic Resonance Spectroscopy
An examination of coaxial stacking of helical stems in a pseudoknot motif: the gene 32 messenger RNA pseudoknot of bacteriophage T2. (1/7271)The RNA pseudoknot located at the 5' end of the gene 32 messenger RNA of bacteriophage T2 contains two A-form helical stems connected by two loops, in an H-type pseudoknot topology. A combination of multidimensional NMR methods and isotope labeling were used to investigate the pseudoknot structure, resulting in a more detailed structural model than provided by earlier homonuclear NMR studies. Of particular significance, the interface between the stacked helical stems within the pseudoknot motif is described in detail. The two stems are stacked in a coaxial manner, with an approximately 18 degrees rotation of stem1 relative to stem2 about an axis that is parallel to the helical axis. This rotation serves to relieve what would otherwise be a relatively close phosphate-phosphate contact at the junction of the two stems, while preserving the stabilizing effects of base stacking. The ability of the NMR data to determine pseudoknot bending was critically assessed. The data were found to be a modestly precise indicator of pseudoknot bending, with the angle between the helical axes of stem1 and stem2 being in the range of 15+/-15 degrees. Pseudoknot models with bend angles within this range are equally consistent with the data, since they differ by only small amounts in the relatively short-range interproton distances from which the structure was derived. The gene 32 messenger RNA pseudoknot was compared with other RNA structures with coaxial or near-coaxial stacked helical stems. (+info)
Prior protein intake may affect phenylalanine kinetics measured in healthy adult volunteers consuming 1 g protein. kg-1. d-1. (2/7271)Study of the amino acid metabolism of vulnerable groups, such as pregnant women, children and patients, is needed. Our existing protocol is preceded by 2 d of adaptation to a low 13C formula diet at a protein intake of 1 g. kg-1. d-1 to minimize variations in breath 13CO2 enrichment and protein metabolism. To expand on our potential study populations, a less invasive protocol needs to be developed. We have already established that a stable background 13CO2 enrichment can be achieved on the study day without prior adaptation to the low 13C formula. Therefore, this study investigates phenylalanine kinetics in response to variations in prior protein intake. Healthy adult subjects were each fed nutritionally adequate mixed diets containing 0.8, 1.4 and 2.0 g protein. kg-1. d-1 for 2 d. On d 3, subjects consumed an amino acid-based formula diet containing the equivalent of 1 g protein. kg-1. d-1 hourly for 10 h and primed hourly oral doses of L-[1-13C]phenylalanine for the final 6 h. Phenylalanine kinetics were calculated from plasma-free phenylalanine enrichment and breath 13CO2 excretion. A significant quadratic response of prior protein intake on phenylalanine flux (P = 0.012) and oxidation (P = 0.009) was identified, such that both variables were lower following adaptation to a protein intake of 1.4 g. kg-1. d-1. We conclude that variations in protein intake, between 0.8 and 2.0 g. kg-1. d-1, prior to the study day may affect amino acid kinetics and; therefore, it is prudent to continue to control protein intake prior to an amino acid kinetics study. (+info)
Carbon 13 NMR study of nonenzymatic reactions of pyridoxal 5'-phosphate with selected amino acids and of related reactions. (3/7271)Carbon 13 nuclear magnetic resonance spectroscopy has been used to monitor the nonenzymatic reactions of pyridoxal 5'-phosphate with glycine, alanine, valine, serine, and with several other model compounds. Isotopically enriched amino acids were employed so that low concentrations could be utilized while still allowing relatively rapid acquisition of spectral data. The results for alanine and serine are particularly noteworthy in that alanine is deaminated to pyruvate and pyruvate is aminated to alanine, but contrary to the enzymatic reactions of various serine dehydratases wherein serine is converted to pyruvate, the nonenzymatic reaction utilizing serine results in hydroxypruvate rather than pyruvate formation. In the reverse reaction, hydroxypyruvate is aminated to serine but very inefficiently relative to the amination of pyruvate to alanine. The experimental results have been formulated into a proposed reaction mechanism for deamination of amino acids by pyridoxal-P. (+info)
The Ice Man's diet as reflected by the stable nitrogen and carbon isotopic composition of his hair. (4/7271)Establishing the diets of ancient human populations is an integral component of most archaeological studies. Stable isotope analysis of well-preserved bone collagen is the most direct approach for a general assessment of paleodiet. However, this method has been limited by the scarcity of well-preserved skeletal materials for this type of destructive analysis. Hair is preserved in many burials, but is often overlooked as an alternative material for isotopic analysis. Here we report that the stable carbon and nitrogen isotope values for the hair of the 5200 year-old Ice Man indicates a primarily vegetarian diet, in agreement with his dental wear pattern. Whereas previous investigations have focused on bone collagen, the stable isotope composition of hair may prove to be a more reliable proxy for paleodiet reconstruction, particularly when skeletal remains are not well preserved and additional archaeological artifacts are unavailable. (+info)
European interlaboratory comparison of breath 13CO2 analysis. (5/7271)The BIOMED I programme Stable Isotopes in Gastroenterology and Nutrition (SIGN) has focused upon evaluation and standardisation of stable isotope breath tests using 13C labelled substrates. The programme dealt with comparison of 13C substrates, test meals, test conditions, analysis techniques, and calculation procedures. Analytical techniques applied for 13CO2 analysis were evaluated by taking an inventory of instrumentation, calibration protocols, and analysis procedures. Two ring tests were initiated measuring 13C abundances of carbonate materials. Evaluating the data it was found that seven different models of isotope ratio mass spectrometers (IRMS) were used by the participants applying both the dual inlet system and the continuous flow configuration. Eight different brands of certified 13C reference materials were used with a 13C abundance varying from delta 13CPDB -37.2 to +2.0/1000. CO2 was liberated from certified material by three techniques and different working standards were used varying from -47.4 to +0.4/1000 in their delta 13CPDB value. The standard deviations (SDs) found for all measurements by all participants were 0.25/1000 and 0.50/1000 for two carbonates used in the ring tests. The individual variation for the single participants varied from 0.02 /1000 (dual inlet system) to 0.14/1000 (continuous flow system). The measurement of the difference between two carbonates showed a SD of 0.33/1000 calculated for all participants. Internal precision of IRMS as indicated by the specifications of the different instrument suppliers is < 0.3/1000 for continuous flow systems. In this respect it can be concluded that all participants are working well within the instrument specifications even including sample preparation. Increased overall interlaboratory variation is therefore likely to be due to non-instrumental conditions. It is possible that consistent differences in sample handling leading to isotope fractionation are the causes for interlaboratory variation. Breath analysis does not require sample preparation. As such, interlaboratory variation will be less than observed for the carbonate samples and within the range indicated as internal precision for continuous flow instruments. From this it is concluded that pure analytical interlaboratory variation is acceptable despite the many differences in instrumentation and analytical protocols. Coordinated metabolic studies appear possible, in which different European laboratories perform 13CO2 analysis. Evaluation of compatibility of the analytical systems remains advisable, however. (+info)
Enzymatic synthesis of natural and 13C enriched linear poly-N-acetyllactosamines as ligands for galectin-1. (6/7271)As part of a study of protein-carbohydrate interactions, linear N-acetyl-polyllactosamines [Galbeta1,4GlcNAcbeta1,3]nwere synthesized at the 10-100 micromol scale using enzymatic methods. The methods described also provided specifically [1-13C]-galactose-labeled tetra- and hexasaccharides ([1-13C]-Galbeta1,4GlcNAcbeta1,3Galbeta1,4Glc and Galbeta1, 4GlcNAcbeta1,3[1-13C]Galbeta1,4GlcNAcbeta1,3Galbeta 1,4Glc) suitable for NMR studies. Two series of oligosaccharides were produced, with either glucose or N-acetlyglucosamine at the reducing end. In both cases, large amounts of starting primer were available from human milk oligosaccharides (trisaccharide primer GlcNAcbeta1,3Galbeta1, 4Glc) or via transglycosylation from N-acetyllactosamine. Partially purified and immobilized glycosyltransferases, such as bovine milk beta1,4 galactosyltransferase and human serum beta1,3 N- acetylglucosaminyltransferase, were used for the synthesis. All the oligo-saccharide products were characterized by1H and13C NMR spectroscopy and MALDI-TOF mass spectrometry. The target molecules were then used to study their interactions with recombinant galectin-1, and initial1H NMR spectroscopic results are presented to illustrate this approach. These results indicate that, for oligomers containing up to eight sugars, the principal interaction of the binding site of galectin-1 is with the terminal N-acetyllactosamine residues. (+info)
Documenting the diet in ancient human populations through stable isotope analysis of hair. (7/7271)Fundamental to the understanding of human history is the ability to make interpretations based on artefacts and other remains which are used to gather information about an ancient population. Sequestered in the organic matrices of these remains can be information, for example, concerning incidence of disease, genetic defects and diet. Stable isotopic compositions, especially those made on isolates of collagen from bones, have been used to help suggest principal dietary components. A significant problem in the use of collagen is its long-term stability, and the possibility of isotopic alteration during early diagenesis, or through contaminating condensation reactions. In this study, we suggest that a commonly overlooked material, human hair, may represent an ideal material to be used in addressing human diets of ancient civilizations. Through the analysis of the amino-acid composition of modern hair, as well as samples that were subjected to radiation (thus simulating ageing of the hair) and hair from humans that is up to 5200 years old, we have observed little in the way of chemical change. The principal amino acids observed in all of these samples are essentially identical in relative abundances and content. Dominating the compositions are serine, glutamic acid, threonine, glycine and leucine, respectively accounting for approximately 15%, 17%, 10%, 8% and 8% of the total hydrolysable amino acids. Even minor components (for example, alanine, valine, isoleucine) show similar constancy between the samples of different ages. This constancy clearly indicates minimal alteration of the amino-acid composition of the hair. Further, it would indicate that hair is well preserved and is amenable to isotopic analysis as a tool for distinguishing sources of nutrition. Based on this observation, we have isotopically characterized modern individuals for whom the diet has been documented. Both stable nitrogen and carbon isotope compositions were assessed, and together provide an indication of trophic status, and principal type (C3 or C4) of vegetation consumed. True vegans have nitrogen isotope compositions of about 7/1000 whereas humans consuming larger amounts of meat, eggs, or milk are more enriched in the heavy nitrogen isotope. We have also analysed large cross-sections of modern humans from North America and Europe to provide an indication of the variability seen in a population (the supermarket diet). There is a wide diversity in both carbon and nitrogen isotope values based at least partially on the levels of seafood, corn-fed beef and grains in the diets. Following analysis of the ancient hair, we have observed similar trends in certain ancient populations. For example, the Coptics of Egypt (1000 BP) and Chinchorro of Chile (5000-800 BP) have diets of similar diversity to those observed in the modern group but were isotopically influenced by local nutritional sources. In other ancient hair (Egyptian Late Middle Kingdom mummies, ca. 4000 BP), we have observed a much more uniform isotopic signature, indicating a more constant diet. We have also recognized a primary vegetarian component in the diet of the Neolithic Ice Man of the Oetztaler Alps (5200 BP). In certain cases, it appears that sulphur isotopes may help to further constrain dietary interpretations, owing to the good preservation and sulphur content of hair. It appears that analysis of the often-overlooked hair in archaeological sites may represent a significant new approach for understanding ancient human communities. (+info)
NMR studies on the 46-kDa dimeric protein, 3,4-dihydroxy-2-butanone 4-phosphate synthase, using 2H, 13C, and 15N-labelling. (8/7271)3,4-Dihydroxy-2-butanone 4-phosphate synthase catalyses the release of C-4 from the substrate, ribulose phosphate, via a complex series of rearrangement reactions. The cognate ribB gene of Escherichia coli was hyperexpressed in a recombinant E. coli strain. The protein was shown to be a 46-kDa homodimer by hydrodynamic analysis. A variety of protein samples labelled with different grades of 13C, 15N and 2H, i.e. one with 100% 2H and 15N, one with 75% 2H, 99% 13C, 15N, and one with 100% 2H, 99% 13C,15N were prepared. Despite the large molecular size, 2- and 3-dimensional NMR spectra of reasonable quality were obtained. Attempts at the assignment of individual 13C, 15N and 1H signals show, in principle, the feasibility of structure determination. The number of NMR signals shows unequivocally that the homodimeric protein obeys strict C2 symmetry. (+info)
In the medical field, carbon isotopes are atoms of carbon that have a different number of neutrons than the most common isotope, carbon-12. There are two stable isotopes of carbon, carbon-12 and carbon-13, and several unstable isotopes that are used in medical applications. Carbon-13, in particular, is used in medical imaging techniques such as magnetic resonance spectroscopy (MRS) and positron emission tomography (PET). In MRS, carbon-13 is used to study the metabolism of certain compounds in the body, such as glucose and amino acids. In PET, carbon-13 is used to create images of the body's metabolism by tracing the movement of a radioactive tracer through the body. Carbon-11, another unstable isotope of carbon, is used in PET imaging to study various diseases, including cancer, Alzheimer's disease, and heart disease. Carbon-11 is produced in a cyclotron and then attached to a molecule that is specific to a particular target in the body. The tracer is then injected into the patient and imaged using a PET scanner to detect the location and extent of the disease. Overall, carbon isotopes play an important role in medical imaging and research, allowing doctors and researchers to better understand the functioning of the body and diagnose and treat various diseases.
In the medical field, the term "carbon" typically refers to the chemical element with the atomic number 6, which is a vital component of all living organisms. Carbon is the building block of organic molecules, including proteins, carbohydrates, lipids, and nucleic acids, which are essential for the structure and function of cells and tissues. In medicine, carbon is also used in various diagnostic and therapeutic applications. For example, carbon-13 (13C) is a stable isotope of carbon that is used in metabolic studies to investigate the function of enzymes and pathways in the body. Carbon-14 (14C) is a radioactive isotope of carbon that is used in radiocarbon dating to determine the age of organic materials, including human remains. Additionally, carbon dioxide (CO2) is a gas that is produced by the body during respiration and is exhaled. It is also used in medical applications, such as in carbon dioxide laser therapy, which uses the energy of CO2 lasers to treat various medical conditions, including skin disorders, tumors, and eye diseases.
In the medical field, isotopes are atoms of the same element that have different numbers of neutrons in their nuclei. These isotopes have the same atomic number (number of protons) but different atomic masses due to the difference in the number of neutrons. Isotopes are used in medical imaging and treatment because they can be used to track the movement of molecules within the body or to deliver targeted radiation therapy. For example, in positron emission tomography (PET) scans, a radioactive isotope is injected into the body and emits positrons, which are detected by a scanner to create images of the body's tissues and organs. In radiation therapy, isotopes such as iodine-131 or cobalt-60 are used to target and destroy cancer cells. There are many different isotopes used in medicine, and their properties are carefully chosen to suit the specific application. Some isotopes are naturally occurring, while others are produced in nuclear reactors or particle accelerators.
In the medical field, oxygen isotopes refer to the different forms of the element oxygen that have different atomic weights due to the presence of different numbers of neutrons in their nuclei. The most common oxygen isotopes are oxygen-16, oxygen-17, and oxygen-18. Oxygen-16 is the most abundant and is the form of oxygen that is found in the air we breathe. Oxygen-17 and oxygen-18 are less abundant and are often used in medical research and diagnostic imaging. Oxygen isotopes can be used to study the metabolism and function of various organs and tissues in the body, and can also be used to diagnose and treat certain medical conditions.
In the medical field, nitrogen isotopes refer to different forms of the element nitrogen that have different atomic masses due to the presence of different numbers of neutrons in their nuclei. The most commonly used nitrogen isotopes in medical applications are nitrogen-13 (13N) and nitrogen-15 (15N). Nitrogen-13 is a radioactive isotope that is commonly used in positron emission tomography (PET) scans to study the function of various organs and tissues in the body. It is produced by bombarding a target material with high-energy protons, and the resulting radioactive nitrogen-13 is then used to create radiotracers that can be injected into the body and imaged using PET. Nitrogen-15, on the other hand, is a stable isotope that is used in various medical applications, including the study of metabolism and the measurement of blood flow. It is often used in combination with other stable isotopes, such as oxygen-15, to create radiotracers that can be used in PET scans. Overall, nitrogen isotopes play an important role in medical imaging and research, allowing doctors and scientists to study the function of various organs and tissues in the body and to diagnose and treat a wide range of medical conditions.
In the medical field, carbon dioxide (CO2) is a gas that is produced as a byproduct of cellular respiration and is exhaled by the body. It is also used in medical applications such as carbon dioxide insufflation during colonoscopy and laparoscopic surgery, and as a component of medical gases used in anesthesia and respiratory therapy. High levels of CO2 in the blood (hypercapnia) can be a sign of respiratory or metabolic disorders, while low levels (hypocapnia) can be caused by respiratory failure or metabolic alkalosis.
Methyl chloride, also known as methyl bromide, is a colorless gas that is used in various industrial and agricultural applications. In the medical field, methyl chloride is not commonly used and is not considered to be a medically important compound. However, it is important to note that methyl chloride is a highly toxic substance and exposure to it can cause serious health problems, including respiratory problems, liver damage, and even death. It is important to handle methyl chloride with care and to follow all safety guidelines when working with this compound.
Ethylene dichloride (EDC) is a colorless, flammable liquid with a sweet and pungent odor. It is a chlorinated hydrocarbon that is primarily used as a solvent in the production of various chemicals, including vinyl chloride, which is used to make polyvinyl chloride (PVC) plastics. In the medical field, ethylene dichloride is not commonly used as a therapeutic agent or medication. However, it has been associated with various health effects, including liver and kidney damage, respiratory problems, and cancer. Exposure to ethylene dichloride can occur through inhalation, ingestion, or skin contact, and it is considered a hazardous substance by regulatory agencies such as the US Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA). In some cases, ethylene dichloride may be used as a preservative in medical devices or as a solvent in the production of certain medical products. However, its use in these applications is typically limited due to its potential health risks.
Methane is not typically used in the medical field. It is a colorless, odorless gas that is the main component of natural gas and is also produced by the digestive processes of some animals, including humans. In the medical field, methane is not used for any therapeutic or diagnostic purposes. However, it can be used as a marker for certain digestive disorders, such as small intestinal bacterial overgrowth, as it is produced by certain types of bacteria in the gut.
Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is produced when fossil fuels such as coal, oil, and gas are burned incompletely. In the medical field, carbon monoxide poisoning is a serious condition that occurs when a person inhales high levels of the gas, which can interfere with the body's ability to transport oxygen to the tissues. Carbon monoxide binds to hemoglobin in red blood cells, forming carboxyhemoglobin, which reduces the amount of oxygen that can be carried by the blood. This can lead to symptoms such as headache, dizziness, nausea, confusion, and shortness of breath. In severe cases, carbon monoxide poisoning can cause unconsciousness, seizures, and even death. The medical treatment for carbon monoxide poisoning involves removing the person from the source of the gas and providing oxygen therapy to help restore normal oxygen levels in the blood. In some cases, additional medical treatment may be necessary to manage symptoms and prevent complications.
In the medical field, carbonates refer to compounds that contain the carbonate ion (CO3^2-), which is formed by combining a carbon atom with three oxygen atoms. Carbonates are commonly found in minerals and rocks, and they can also be produced synthetically. In medicine, carbonates are used as antacids to neutralize stomach acid and relieve heartburn and indigestion. They work by binding to the hydrogen ions in stomach acid, reducing its acidity and making it less irritating to the lining of the esophagus and stomach. Some common examples of carbonates used in medicine include sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and calcium carbonate (CaCO3). These compounds are often combined with other ingredients, such as magnesium hydroxide or aluminum hydroxide, to create more effective antacids. It's worth noting that while carbonates can be effective at relieving symptoms of acid reflux and heartburn, they should not be used as a long-term solution for these conditions. If you experience frequent or persistent heartburn or acid reflux, it's important to speak with a healthcare provider to determine the underlying cause and develop a more effective treatment plan.
Carbon nanotubes are cylindrical structures made of carbon atoms arranged in a hexagonal lattice. They are typically only a few nanometers in diameter and can be several micrometers long. In the medical field, carbon nanotubes have been studied for their potential use in a variety of applications, including drug delivery, imaging, and tissue engineering. For example, carbon nanotubes can be functionalized with drugs and used to deliver them directly to specific cells or tissues in the body. They can also be used as contrast agents in medical imaging, and their unique mechanical and electrical properties make them attractive for use in tissue engineering scaffolds. However, the use of carbon nanotubes in medicine is still in the early stages of development, and more research is needed to fully understand their potential benefits and risks.
In the medical field, "Carbon Compounds, Inorganic" refers to compounds that contain carbon but do not contain hydrogen. These compounds are typically formed by the reaction of carbon with other elements, such as oxygen, nitrogen, sulfur, or halogens. Examples of inorganic carbon compounds include carbon dioxide (CO2), carbon monoxide (CO), and calcium carbonate (CaCO3). These compounds can play important roles in various physiological processes, such as respiration, metabolism, and bone formation. In some cases, inorganic carbon compounds can also be toxic or harmful to the body if they are present in high concentrations or if they are not properly metabolized.
Epitestosterone is a naturally occurring hormone in the human body that is chemically similar to testosterone. It is produced in the adrenal glands and is a minor component of the male sex hormone complex. In the medical field, epitestosterone is often measured in blood or urine as a way to assess the function of the adrenal glands and to diagnose certain conditions, such as congenital adrenal hyperplasia (CAH), which is a genetic disorder that affects the adrenal glands. Epitestosterone levels can also be used to monitor the effectiveness of hormone replacement therapy in individuals with low testosterone levels due to conditions such as hypogonadism or andropause (male menopause). Additionally, elevated levels of epitestosterone can be a sign of certain types of cancer, such as prostate cancer or ovarian cancer.
In the medical field, nitrogen is a chemical element that is commonly used in various medical applications. Nitrogen is a non-metallic gas that is essential for life and is found in the air we breathe. It is also used in the production of various medical gases, such as nitrous oxide, which is used as an anesthetic during medical procedures. Nitrogen is also used in the treatment of certain medical conditions, such as nitrogen narcosis, which is a condition that occurs when a person breathes compressed air that contains high levels of nitrogen. Nitrogen narcosis can cause symptoms such as dizziness, confusion, and disorientation, and it is typically treated by reducing the amount of nitrogen in the air that the person is breathing. In addition, nitrogen is used in the production of various medical devices and equipment, such as medical imaging equipment and surgical instruments. It is also used in the production of certain medications, such as nitroglycerin, which is used to treat heart conditions. Overall, nitrogen plays an important role in the medical field and is used in a variety of medical applications.
In the medical field, water is a vital substance that is essential for the proper functioning of the human body. It is a clear, odorless, tasteless liquid that makes up the majority of the body's fluids, including blood, lymph, and interstitial fluid. Water plays a crucial role in maintaining the body's temperature, transporting nutrients and oxygen to cells, removing waste products, and lubricating joints. It also helps to regulate blood pressure and prevent dehydration, which can lead to a range of health problems. In medical settings, water is often used as a means of hydration therapy for patients who are dehydrated or have fluid imbalances. It may also be used as a diluent for medications or as a component of intravenous fluids. Overall, water is an essential component of human health and plays a critical role in maintaining the body's normal functions.
Zinc isotopes are different forms of the element zinc that have different atomic weights due to the number of neutrons in their nuclei. In the medical field, zinc isotopes are used in various diagnostic and therapeutic applications. One common use of zinc isotopes in medicine is in nuclear medicine imaging. For example, the isotope zinc-67 is used to label antibodies and other molecules for imaging purposes. When injected into the body, the labeled molecules can be tracked using a gamma camera, allowing doctors to visualize the distribution of the molecules in the body and diagnose various diseases. Zinc isotopes are also used in radiation therapy for cancer treatment. For example, the isotope zinc-70 has been shown to be effective in killing cancer cells while minimizing damage to healthy tissue. In this application, zinc isotopes are used to target cancer cells specifically, allowing for more precise and effective treatment. Overall, zinc isotopes play an important role in medical imaging and cancer treatment, and ongoing research is exploring new applications for these isotopes in the field of medicine.
Phosphoenolpyruvate carboxylase (PEP carboxylase) is an enzyme that plays a crucial role in the metabolism of plants, algae, and some bacteria. It catalyzes the carboxylation of phosphoenolpyruvate (PEP) to form oxaloacetate, a key intermediate in the citric acid cycle. In plants, PEP carboxylase is primarily found in the cytosol and chloroplasts and is involved in the process of photosynthesis. It is responsible for fixing carbon dioxide (CO2) into organic molecules, which is an essential step in the production of glucose and other sugars that are used for energy and growth. PEP carboxylase is also involved in the metabolism of some bacteria and microorganisms, where it plays a role in the synthesis of amino acids and other organic compounds. In the medical field, PEP carboxylase has been studied as a potential target for the development of new drugs to treat metabolic disorders such as diabetes and obesity. Additionally, PEP carboxylase has been shown to play a role in the development of certain types of cancer, and its inhibition has been proposed as a potential therapeutic strategy for these diseases.
In the medical field, "soil" typically refers to the microorganisms and other biological material that can be found in soil. These microorganisms can include bacteria, viruses, fungi, and parasites, and can be present in various forms, such as in soil particles or as free-living organisms. Soil can also refer to the physical and chemical properties of the soil, such as its texture, pH, nutrient content, and water-holding capacity. These properties can affect the growth and health of plants, and can also impact the spread of soil-borne diseases and infections. In some cases, soil can also be used as a medium for growing plants in a controlled environment, such as in a greenhouse or laboratory setting. In these cases, the soil may be specially formulated to provide the necessary nutrients and conditions for optimal plant growth.
Sulfur isotopes are atoms of sulfur that have different numbers of neutrons in their nuclei, resulting in different atomic masses. In the medical field, sulfur isotopes are often used in diagnostic imaging techniques, such as positron emission tomography (PET) scans. For example, sulfur-35 (35S) and sulfur-75 (75S) are commonly used as tracers to study the metabolism of sulfur-containing compounds in the body, such as amino acids and neurotransmitters. These isotopes can be administered to a patient in the form of a radiolabeled compound, and the distribution and metabolism of the compound can be monitored using PET imaging. This information can be used to diagnose and monitor a variety of medical conditions, including neurological disorders, cancer, and cardiovascular disease.
Ribulose-1,5-bisphosphate carboxylase (RuBisCO) is an enzyme that plays a central role in the process of photosynthesis in plants, algae, and some bacteria. It catalyzes the reaction between carbon dioxide and ribulose-1,5-bisphosphate (RuBP), a 5-carbon sugar, to form two molecules of 3-phosphoglycerate (3-PGA), a 3-carbon compound. This reaction is the first step in the Calvin cycle, which is the primary pathway for carbon fixation in photosynthesis. RuBisCO is the most abundant enzyme on Earth and is responsible for fixing approximately 60% of the carbon dioxide in the atmosphere. However, it is also a slow enzyme and is often limited by the availability of carbon dioxide in the environment. This can lead to a phenomenon known as photorespiration, in which RuBisCO instead catalyzes the reaction between RuBP and oxygen, leading to the loss of carbon dioxide and the production of a variety of byproducts. In the medical field, RuBisCO has been studied as a potential target for the development of new drugs to treat a variety of conditions, including cancer, diabetes, and obesity. Some researchers have also explored the use of RuBisCO as a biosensor for detecting carbon dioxide levels in the environment or as a tool for producing biofuels.
Carbon monoxide poisoning is a medical emergency that occurs when a person inhales carbon monoxide (CO), a colorless, odorless gas that is produced when fossil fuels such as coal, oil, and gas are burned incompletely. When inhaled, carbon monoxide binds to hemoglobin in the blood, which is responsible for carrying oxygen to the body's tissues. This binding prevents oxygen from being transported to the body's cells, leading to a lack of oxygen (hypoxia) and potentially causing damage to the brain, heart, and other organs. Symptoms of carbon monoxide poisoning can include headache, dizziness, nausea, vomiting, confusion, and loss of consciousness. In severe cases, carbon monoxide poisoning can lead to death. Treatment for carbon monoxide poisoning typically involves removing the person from the source of the gas and providing oxygen therapy to increase the amount of oxygen in the blood. In some cases, additional medical treatment may be necessary to manage symptoms and prevent complications.
Deuterium is a stable isotope of hydrogen that has one extra neutron in its nucleus compared to the most common isotope of hydrogen, protium. In the medical field, deuterium is sometimes used as a tracer in nuclear medicine imaging studies. For example, deuterium oxide (heavy water) can be used to label certain molecules, such as glucose or amino acids, which can then be injected into the body and imaged using positron emission tomography (PET) or single-photon emission computed tomography (SPECT). This can help doctors to visualize the uptake and metabolism of these molecules in different tissues and organs, which can be useful for diagnosing and monitoring various medical conditions. Deuterium is also used in some types of radiation therapy, where it is used to replace hydrogen atoms in certain molecules to make them more radioactive, allowing them to be targeted to specific cancer cells.
Iron isotopes refer to the different forms of the element iron, which have different atomic weights due to the number of neutrons in their nuclei. In the medical field, iron isotopes are often used in diagnostic imaging studies to evaluate iron metabolism and storage in the body. One commonly used iron isotope in medical imaging is iron-59, which is a radioactive isotope that can be injected into the bloodstream and taken up by iron-containing cells in the body. By measuring the amount of iron-59 that is taken up by different organs or tissues, doctors can gain insights into iron metabolism and storage in the body, which can be useful in diagnosing and treating conditions such as anemia, iron overload, and liver disease. Another iron isotope that is used in medical imaging is iron-52, which is a stable isotope that can be used to label iron-containing proteins such as transferrin, the protein that carries iron in the bloodstream. By injecting iron-52-labeled transferrin into the bloodstream and imaging the distribution of the labeled protein in the body, doctors can study the uptake and transport of iron in the body and gain insights into iron metabolism and storage.
In the medical field, acetates refer to compounds that contain the acetate ion (CH3COO-). Acetates are commonly used in the treatment of various medical conditions, including: 1. Hyperkalemia: Acetate is used to treat high levels of potassium (hyperkalemia) in the blood. It works by binding to potassium ions and preventing them from entering cells, which helps to lower potassium levels in the blood. 2. Acidosis: Acetate is used to treat acidosis, a condition in which the blood becomes too acidic. It works by increasing the production of bicarbonate ions, which helps to neutralize excess acid in the blood. 3. Respiratory failure: Acetate is used to treat respiratory failure, a condition in which the lungs are unable to provide enough oxygen to the body. It works by providing an alternative source of energy for the body's cells, which helps to support the respiratory system. 4. Metabolic acidosis: Acetate is used to treat metabolic acidosis, a condition in which the body produces too much acid. It works by increasing the production of bicarbonate ions, which helps to neutralize excess acid in the body. 5. Hyperammonemia: Acetate is used to treat hyperammonemia, a condition in which the blood contains too much ammonia. It works by providing an alternative source of energy for the body's cells, which helps to reduce the production of ammonia. Overall, acetates are a useful tool in the treatment of various medical conditions, and their use is closely monitored by healthcare professionals to ensure their safe and effective use.
In the medical field, sulfates refer to compounds that contain the sulfate ion (SO4^2-). Sulfates are commonly found in many minerals and are also produced by the body as a byproduct of metabolism. Sulfates are often used in medical treatments, particularly in the treatment of respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). They work by helping to thin mucus in the lungs, making it easier to cough up and reducing the risk of infection. Sulfates are also used in the treatment of certain skin conditions, such as psoriasis and eczema, as well as in the treatment of gout, a type of arthritis caused by high levels of uric acid in the blood. In addition to their therapeutic uses, sulfates are also used in the production of a variety of industrial and commercial products, including detergents, fertilizers, and plastics.
Strontium isotopes are radioactive forms of the element strontium that are used in the medical field for various diagnostic and therapeutic purposes. One common use of strontium isotopes is in bone scans, which are used to diagnose bone diseases such as osteoporosis, bone cancer, and bone infections. Strontium-89 and strontium-90 are two isotopes that are commonly used for this purpose. These isotopes are administered orally or intravenously and are taken up by the bones, where they emit gamma rays that can be detected by a gamma camera. The amount of radiation absorbed by the bones can be used to determine the extent and severity of bone disease. Strontium isotopes are also used in radiation therapy for certain types of cancer, such as prostate cancer and bone metastases. Strontium-89 is particularly effective in this application because it emits beta particles that can destroy cancer cells in the bone while minimizing damage to surrounding healthy tissue. In addition, strontium isotopes have been used in research to study bone metabolism and to develop new treatments for bone diseases.
Carbon tetrachloride is a colorless, dense liquid with a sweet, chlorinated smell. It is a commonly used solvent in the medical field, particularly in the preparation of medications and in the sterilization of medical equipment. However, carbon tetrachloride is also a known neurotoxin and can cause serious health problems if inhaled or ingested in large quantities. It has been linked to liver damage, kidney damage, and even death in severe cases. As a result, its use in the medical field has been largely phased out in favor of safer alternatives.
Carbon disulfide (CS2) is a colorless, highly toxic gas that is used in various industrial processes, including the production of rayon and certain types of plastics. In the medical field, carbon disulfide is primarily associated with its toxic effects on the nervous system and the lungs. Exposure to carbon disulfide can cause a range of symptoms, including headache, dizziness, nausea, vomiting, and confusion. In severe cases, exposure to high levels of carbon disulfide can lead to respiratory failure, coma, and death. In addition to its acute toxic effects, carbon disulfide has also been linked to long-term health effects, including damage to the liver, kidneys, and nervous system. Chronic exposure to low levels of carbon disulfide has been associated with an increased risk of certain types of cancer, including lung cancer and bladder cancer. Overall, carbon disulfide is a highly toxic substance that should be handled with extreme caution in the workplace and other settings where it is used. Medical professionals should be aware of the potential health effects of carbon disulfide and take appropriate precautions to protect themselves and others from exposure.
In the medical field, carbon radioisotopes are isotopes of carbon that emit radiation. These isotopes are often used in medical imaging techniques, such as positron emission tomography (PET), to visualize and diagnose various diseases and conditions. One commonly used carbon radioisotope in medical imaging is carbon-11, which is produced by bombarding nitrogen-14 with neutrons in a nuclear reactor. Carbon-11 is then incorporated into various molecules, such as glucose, which can be injected into the body and taken up by cells that are metabolically active. The emitted radiation from the carbon-11 can then be detected by a PET scanner, allowing doctors to visualize and diagnose conditions such as cancer, Alzheimer's disease, and heart disease. Other carbon radioisotopes used in medicine include carbon-13, which is used in breath tests to diagnose various digestive disorders, and carbon-14, which is used in radiocarbon dating to determine the age of organic materials.
Carbon tetrachloride poisoning is a medical condition that occurs when a person is exposed to high levels of carbon tetrachloride, a colorless, sweet-smelling liquid that was once commonly used as a solvent in various industrial and household products. The symptoms of carbon tetrachloride poisoning can vary depending on the level and duration of exposure, but they may include headache, dizziness, nausea, vomiting, abdominal pain, confusion, and difficulty breathing. In severe cases, carbon tetrachloride poisoning can lead to liver damage, kidney failure, and even death. The treatment for carbon tetrachloride poisoning typically involves supportive care, such as oxygen therapy, fluid replacement, and medications to manage symptoms. In some cases, activated charcoal may be given to help absorb the carbon tetrachloride from the body. Prevention of carbon tetrachloride poisoning involves avoiding exposure to the chemical, especially in its pure form, and using safer alternatives whenever possible. If you suspect that you or someone else may have been exposed to carbon tetrachloride, seek medical attention immediately.
In the medical field, hydrogen is not typically used as a standalone treatment or medication. However, there is some research being conducted on the potential therapeutic uses of hydrogen gas (H2) in various medical conditions. One area of interest is in the treatment of oxidative stress and inflammation, which are underlying factors in many chronic diseases such as cancer, diabetes, and neurodegenerative disorders. Hydrogen gas has been shown to have antioxidant and anti-inflammatory effects, and some studies have suggested that it may have potential as a therapeutic agent in these conditions. Another area of research is in the treatment of traumatic brain injury (TBI). Hydrogen gas has been shown to reduce oxidative stress and inflammation in animal models of TBI, and some studies have suggested that it may have potential as a neuroprotective agent in humans. However, it's important to note that the use of hydrogen gas in medicine is still in the early stages of research, and more studies are needed to fully understand its potential therapeutic benefits and risks. As such, hydrogen gas should not be used as a substitute for conventional medical treatments without the guidance of a qualified healthcare professional.
Mercury isotopes refer to the different forms of the element mercury that have different atomic weights due to the number of neutrons in their nuclei. In the medical field, the most commonly studied mercury isotopes are: 1. Mercury-202: This is the most abundant isotope of mercury, making up about 80% of naturally occurring mercury. It is not radioactive and is not considered a health hazard. 2. Mercury-203: This is a radioactive isotope of mercury that decays by beta emission to form thallium-203. It has a half-life of about 46 days and is used in some medical imaging procedures. 3. Mercury-204: This is another radioactive isotope of mercury that decays by alpha emission to form thallium-204. It has a half-life of about 11.4 years and is used in some medical imaging procedures. 4. Mercury-206: This is a stable isotope of mercury that is not radioactive and is not considered a health hazard. 5. Mercury-208: This is another stable isotope of mercury that is not radioactive and is not considered a health hazard. Mercury isotopes can be measured in the body using various analytical techniques, such as mass spectrometry, to provide information about mercury exposure and toxicity. In some cases, the measurement of mercury isotopes can be used to distinguish between different sources of mercury exposure, such as natural sources and human activities.
Deuterium oxide, also known as heavy water, is a chemical compound composed of one oxygen atom and two deuterium atoms. It has the chemical formula D2O and is a colorless, odorless, and tasteless liquid that is similar in appearance and properties to regular water (H2O). In the medical field, deuterium oxide is used as a tracer in nuclear magnetic resonance (NMR) spectroscopy, a non-invasive imaging technique that can provide detailed information about the structure and function of molecules in the body. Deuterium oxide is often used as a substitute for regular water in NMR studies because its slightly different chemical properties allow it to be distinguished from regular water in the spectra. Deuterium oxide has also been used in some clinical trials as a potential treatment for certain medical conditions, such as cancer and heart disease. However, its use in medicine is still limited and more research is needed to fully understand its potential benefits and risks.
In the medical field, oxygen is a gas that is essential for the survival of most living organisms. It is used to treat a variety of medical conditions, including respiratory disorders, heart disease, and anemia. Oxygen is typically administered through a mask, nasal cannula, or oxygen tank, and is used to increase the amount of oxygen in the bloodstream. This can help to improve oxygenation of the body's tissues and organs, which is important for maintaining normal bodily functions. In medical settings, oxygen is often used to treat patients who are experiencing difficulty breathing due to conditions such as pneumonia, chronic obstructive pulmonary disease (COPD), or asthma. It may also be used to treat patients who have suffered from a heart attack or stroke, as well as those who are recovering from surgery or other medical procedures. Overall, oxygen is a critical component of modern medical treatment, and is used in a wide range of clinical settings to help patients recover from illness and maintain their health.
Radioisotopes are isotopes of an element that emit radiation, such as alpha particles, beta particles, or gamma rays. In the medical field, radioisotopes are used in a variety of diagnostic and therapeutic applications. In diagnostic imaging, radioisotopes are used to create images of the body's internal structures. For example, a radioisotope such as technetium-99m can be injected into the bloodstream and then detected by a gamma camera to create an image of the heart, lungs, or other organs. This type of imaging is commonly used to diagnose conditions such as cancer, heart disease, and bone disorders. Radioisotopes are also used in therapeutic applications, such as radiation therapy for cancer. In this treatment, a radioisotope is introduced into the body, usually by injection or inhalation, and then targeted to a specific area of the body where it emits radiation that destroys cancer cells. Radioisotopes are also used in targeted radionuclide therapy, where a radioisotope is attached to a molecule that specifically targets cancer cells, allowing for more precise delivery of radiation. Overall, radioisotopes play a critical role in medical imaging and therapy, allowing for the diagnosis and treatment of a wide range of conditions.
Glucose is a simple sugar that is a primary source of energy for the body's cells. It is also known as blood sugar or dextrose and is produced by the liver and released into the bloodstream by the pancreas. In the medical field, glucose is often measured as part of routine blood tests to monitor blood sugar levels in people with diabetes or those at risk of developing diabetes. High levels of glucose in the blood, also known as hyperglycemia, can lead to a range of health problems, including heart disease, nerve damage, and kidney damage. On the other hand, low levels of glucose in the blood, also known as hypoglycemia, can cause symptoms such as weakness, dizziness, and confusion. In severe cases, it can lead to seizures or loss of consciousness. In addition to its role in energy metabolism, glucose is also used as a diagnostic tool in medical testing, such as in the measurement of blood glucose levels in newborns to detect neonatal hypoglycemia.
In the medical field, soot is a type of fine black or brown particulate matter that is produced by incomplete combustion of carbon-based fuels, such as coal, wood, and oil. Soot particles can be inhaled into the lungs and can cause a range of health problems, including respiratory irritation, inflammation, and damage to lung tissue. Long-term exposure to soot has been linked to an increased risk of chronic obstructive pulmonary disease (COPD), lung cancer, and cardiovascular disease. In some cases, soot exposure can also cause skin irritation and other dermatological problems.
Carboxyhemoglobin (COHb) is a type of hemoglobin (the protein in red blood cells that carries oxygen) that has bound to carbon monoxide (CO) molecules. When carbon monoxide binds to hemoglobin, it prevents the hemoglobin from binding to oxygen, which can lead to a decrease in the amount of oxygen that is delivered to the body's tissues. This can cause symptoms such as headache, dizziness, confusion, and in severe cases, loss of consciousness and death. Carboxyhemoglobin levels can be measured in the blood using a blood gas test.
Isotopes of carbon
Fractionation of carbon isotopes in oxygenic photosynthesis
Steptoean positive carbon isotope excursion
Isotopes in medicine
Kinetic isotope effect
Isotopes of neon
Reference materials for stable isotope analysis
Hydrogen isotope biogeochemistry
High Flux Isotope Reactor
Stable isotope composition of amino acids
Methane clumped isotopes
Evolutionary history of plants
Isotope analysis in archaeology
Isotopes of nitrogen
Isotopically pure diamond
Table of nuclides
Silicon isotope biogeochemistry
Isotope-ratio mass spectrometry
Oceanic carbon cycle
Pleistocene human diet
Total inorganic carbon
PDF) Diet of ancient Egyptians inferred from stable isotope systematics
Stable carbon isotopes as indicators for environmental change in palsa peats
Beyond width and density: stable carbon and oxygen isotopes in cork-rings provide insights of physiological responses to water...
Isotopes & Relative Atomic Mass (solutions, examples, videos)
USGS: Coastal and Marine Geosciences Data System: carbon isotope analysis
An evaluation of lipid extraction techniques for interpretation of carbon and nitrogen isotope values in bottlenose dolphin ...
Influence of forage preferences and habitat use on 13C and 15N abundance in wild caribou (Rangifer tarandus caribou) and moose ...
Silicon isotopes highlight the role of glaciated fjords in modifying coastal waters - British Antarctic Survey
Stable oxygen and carbon isotope record of stalagmite C09-2 from Closani Cave - Dataset - B2FIND
Oxygen and carbon isotope signatures of Miocene molluscs in the Central Paratethys<...
Tests for H pylori: MedlinePlus Medical Encyclopedia
WTS database | WHO FCTC
Distribution of hydrogen isotopes, carbon and beryllium on in-vessel surfaces in the various JET divertors<...
ERDC Knowledge Core: Using stable isotopes of carbon and nitrogen as in-situ tracers for monitoring the natural attenuation of...
The association between carbon and nitrogen stable isotope ratios of human hair and hypertension<...
NHANES 2003-2004: Polyaromatic Hydrocarbons (PAHs) - Urine Data Documentation, Codebook, and Frequencies
Details for: Bacteria, elemental sulfur and stable carbon isotope rations in the mangrove mud clam Anodontia Edentula ...
Seasonal carbon allocation to arbuscular mycorrhizal fungi assessed by microscopic examination, stable isotope probing and...
Carbon and nitrogen stabile isotope ratio and heavy metals in Leccinum aurantiacum in a hybrid aspen plantation in agricultural...
Supplemental Material: High-resolution record of multiple organic carbon-isotope excursions in lacustrine deposits of Upper...
feeding, and reproduction by the predatory beetle, Hippodamia convergens, as indicated by stable carbon isotope analysis Crop...
Dental calculus is not equivalent to bone collagen for isotope analysis: a comparison between carbon and nitrogen stable...
Increased risk to the public from rockfalls as a result of the forecasted heatwave - British Geological Survey
Infrared spectroscopy refines chronological assessment, depositional environment and pyrolysis conditions of archeological...
Wubet, Tesfaye - Helmholtz-Centre for Environmental Research
Page 9 | Lamont-Doherty Earth Observatory
Methane pockets may narrow search for Mars life | New Scientist
- Maturities derived from carbon and hydrogen isotopes can serve as controls in regional maturity maps, which are used to help define areas of oil, wet gas and dry gas production. (onepetro.org)
- Stable carbon (δ¹³C) and hydrogen (δ²H) isotopes have been used to characterize hydrocarbons for exploration, development and production since the 1960s, and have re-emerged as predictive tools with the development of unconventional "tight" oil and gas plays. (onepetro.org)
- Stable carbon and hydrogen isotope values show a strong correlation to both initial and cumulative GOR for the unconventional Niobrara and Codell intervals of Wattenberg Field. (onepetro.org)
- We used stable carbon isotope depth profiles in two palsa mires of Northern Sweden to track environmental change during the formation of the mires. (unibas.ch)
- In soils with suppressed degradation due to anoxic conditions, stable carbon isotope depth profiles are either more or less uniform indicating no or very low degradation or depth profiles turn to lighter values due to an enrichment of recalcitrant organic substances during anaerobic mineralisation which are depleted in 13C. (unibas.ch)
- Experimental determination of the proportion of a given stable carbon isotope (C12 or C13) in a sample. (usgs.gov)
- Bacteria, elemental sulfur and stable carbon isotope rations in the mangrove mud clam Anodontia Edentula (Linne, 1758) / by Ma. (edu.ph)
- Bacteria, elemental sulfur and stable carbon isotope ratios in the mangrove mud clam Anodontia edentula (Linné, 1758). (edu.ph)
- and stable carbon isotope ratios of the clams, sediment, detritus and plankton in the study area were determined. (edu.ph)
- 2. Stable carbon isotopes were used in complementary laboratory and field studies to examine colonisation behaviour of an ephemeral agricultural habitat by the lady beetle, Hippodamia convergens Gurin-Mneville. (tamu.edu)
- In this study, we address the relation between carbon and oxygen stable isotopes of cork rings and precipitation and temperature, in two distinct locations of southwestern Portugal-the (wetter) Tagus basin peneplain and the (drier) Grândola mountains. (unl.pt)
- We aimed at assessing whether the two climatic factors affect cork-ring isotopic composition under contrasting conditions of water availability, and, therefore, if carbon and oxygen signatures in cork can reflect tree functional (physiological and structural) responses to stressful conditions, which might be aggravated by climate change. (unl.pt)
- cellulose extraction and blue-stain fungus on retrospective studies of carbon and oxygen isotope variation in live and dead trees. (bvsalud.org)
- Tree -ring carbon and oxygen isotope ratios from live and recently dead trees may reveal important mechanisms of tree mortality . (bvsalud.org)
- Latal, C , Piller, WE & Harzhauser, M 2003, Oxygen and carbon isotope signatures of Miocene molluscs in the Central Paratethys . (elsevierpure.com)
- Abstract: The use of carbon and nitrogen stable isotope measurements from TNT was examined as a possible tool for monitoring the natural attenuation of TNT. (dren.mil)
- Figure S1: Stratigraphic log with the positions of the samples collected for isotope and palynological analyses at the Dacao "A," Dacao "B," and Liangshuijing sections. (figshare.com)
- Here we report the comparison of carbon and nitrogen stable isotope analyses of bulk calculus to those from bone and dentine collagen. (uv.es)
- These analyses have been performed on individuals from the El Raval Mudéjar Medieval Cemetery (Eastern Iberia, 15th century A.D.). Although calculus isotope values may be broadly similar to expected values at the population level, we report here no correlation between collagen and bulk dental calculus values at the individual level. (uv.es)
Ratios of carbon4
- We investigated whether the stable isotope ratios of carbon and nitrogen in human hair are associated with blood pressure and hypertension. (ewha.ac.kr)
- Hair samples of the subjects were used for the measurement of stable isotope ratios of carbon (δ 13 C) and nitrogen (δ 15 N). Results: The δ 13 C and δ 15 N values showed positive correlations with diastolic blood pressure in the subjects without antihypertensive medication. (ewha.ac.kr)
- Hair samples of the subjects were used for the measurement of stable isotope ratios of carbon (δ13C) and nitrogen (δ15N). (ewha.ac.kr)
- This was shown by the more negative 613C ratios of carbon fixed during bacterial chemoautotrophy compared to carbon fixed photosynthetically. (edu.ph)
- This method uses isotope dilution with carbon-13 labeled internal standards. (cdc.gov)
- A new technique simultaneously analyzes serum and plasma testosterone, adrenostenedione, and DHEA levels using isotope-dilution liquid-chromatography tandem mass spectrometry. (medscape.com)
- Determination of 3-quinuclidinyl benzilate (QNB) and its major metabolites in urine by isotope dilution gas chromatography/mass spectrometry. (cdc.gov)
- Therefore we evaluated the carbon and nitrogen stable isotope ratio and content of heavy metals (Cr, Pb, Mn, Ni, Cd, Cu and Zn) in Leccinum aurantiacum (Bull. (lammc.lt)
- 6. With cotton aphids present, beetle isotope ratios decreased towards the carbon isotope ratio of cotton, indicating adult feeding in cotton. (tamu.edu)
- 13C by isotope ratio mass spectrometry. (cdc.gov)
- These results demonstrate the potential of natural gas stable isotope signatures as a useful and reliable fluid quality prediction tool. (onepetro.org)
- These results suggest that although stable isotopes signatures in cork rings are not proxies for net growth, they may be (fairly) robust indicators of trees' physiological and structural adjustments to climate and environmental changes in Mediterranean environments. (unl.pt)
- Stable isotope analysis can be executed pre-completion on samples obtained from mud gas and/or gas desorbing from cuttings and core. (onepetro.org)
- Compound‐specific carbon isotope analysis (δ13C) of meteoritic organic compounds can be used to elucidate the abiotic chemical reactions involved in their synthesis. (macewan.ca)
- Stable isotope (SI) analysis studies rely on knowledge of isotopic turnover rates and trophic-step discrimination factors. (springer.com)
- Dental calculus is not equivalent to bone collagen for isotope analysis: a comparison between carbon and nitrogen stable isotope analysis of bulk dental calculus, bone and dentine collagen from same individuals from the Medieval site of El Raval (Alicante, Spain). (uv.es)
- As a result, we recommend that carbon and nitrogen analysis on bulk dental calculus should only be used as a last resource archaeological dietary marker, if at all. (uv.es)
- Salazar García, Domingo Carlos Richards, M.P. Nehlich, O. Henry, A.G. 2014 Dental calculus is not equivalent to bone collagen for isotope analysis: a comparison between carbon and nitrogen stable isotope analysis of bulk dental calculus, bone and dentine collagen from same individuals from the Medieval site of El Raval (Alicante, Spain). (uv.es)
- The organic sediment within coastal wetlands is composed of carbon sequestered over the time scale of the wetland's existence. (usgs.gov)
- Eelgrass (Zostera marina) characteristics, sediment grain size distributions, sediment total organic carbon contents (TOC), carbon isotope ratios of sediment organic matter, and total carbon to total nitrogen ratios were measured at four lower intertidal sites in Bellingham Bay, Washington, July 2-5, 2019. (usgs.gov)
- Stable C isotope ratios showed that the clams do not obtain their carbon from plankton, sediment nor detritus and may thus be solely dependent on bacterial carbon. (edu.ph)
- Isotopes are atoms of the same element that have different number of neutrons. (onlinemathlearning.com)
- Some of the atoms of certain isotopes are unstable because of the extra number of neutrons, and they are said to be radioactive. (onlinemathlearning.com)
- Learn how to write atoms in isotope notation! (onlinemathlearning.com)
- Dehydroepiandrosterone (DHEA) is a C-19 (19 carbon atoms) steroid hormone and one of three androgens (DHEA, DHEA-S, androstenedione) secreted by the adrenal gland. (medscape.com)
- If H pylori are present, the bacteria convert the urea into carbon dioxide, which is detected and recorded in your exhaled breath after 10 minutes. (medlineplus.gov)
- Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. (who.int)
- Beta particle ( ionizing radiation ) - a charged particle emitted from the nucleus of certain unstable atomic nuclei (radioactive isotopes), having the charge and mass of an electron. (cdc.gov)
- Alpha particle ( ionizing radiation ) - two neutrons and two protons bound as a single particle (a helium nucleus) that is emitted from the nucleus of certain radioactive isotopes in the process of disintegration. (cdc.gov)
- Background radioactivity - radioactive elements in the natural environment including those in the crust of the earth (like radioactive potassium, uranium, and thorium isotopes) and those produced by cosmic rays. (cdc.gov)
- The San Juan Bay Estuary, Puerto Rico, contains mangrove forests that store significant amounts of organic carbon in soils and biomass. (usgs.gov)
- Per- and polyfluoroalkyl substances (PFAS), man-made chemicals with variable length carbon chains containing the perfluoroalkyl moiety (CnF2n+1-), are used in many commercial applications. (cdc.gov)
- Validation of the correlation between Niobrara and Codell production GOR and stable isotope composition was provided by an independent geochemistry dataset from the USGS. (onepetro.org)
- Stable isotope composition (delta(13)C and delta(15)N) of moose (Alces alces) and caribou (Rangifer tarandus) hair from the boreal forest of Jacques-Cartier Park and Cote-Nord (Quebec) and arctic tundra of Queen Maud Gulf and Southampton Island (Nunavut) was investigated as an indicator of dietary preferences and habitat use. (nih.gov)
- We thus concluded that differences in carbon isotope profiles of the hollows might point to the disturbance of the mires due to climate warming or due to differences in hydrology. (unibas.ch)
- Isotopes and isotope notation are particularly important in nuclear chemistry. (onlinemathlearning.com)
- Isotope notation is particularly important in nuclear chemistry, because if you're doing fission, fusion, alpha decay, beta decay, positron emission, or electron capture, you want to be able to tell how many neutrons and protons are in the nucleus. (onlinemathlearning.com)
- Stable isotope turnover rates represent the change in mass and/or time required for consumer tissues to reflect their new diet, allowing the calculation of an isotopic half-life for the tissue and isotope of interest (Boecklen et al. (springer.com)
- 3. Under laboratory conditions, H. convergens carbon isotope ratios, 13C, changed after its food supply was shifted from a C4- to a C3-based diet of aphids produced on grain sorghum or cotton respectively. (tamu.edu)
- Final isotope ratios of adult H. convergens were closer to that of the new C3-based diet, with most change in 13C occurring within 3 days after the diet shift. (tamu.edu)
- It is not yet clear how much of an individual¿s life span dental calculus represents, what portions of the diet it records, and how diagenesis effects the carbon and nitrogen isotope values of this material. (uv.es)
- The objective of our pilot study was to determine whether ultrafine elemental carbon particles translocate to the liver and other extrapulmonary organs following inhalation as singlet particles by rats. (cdc.gov)
- Noninvasive diagnostic studies include the carbon 13 urea breath test (UBT), fecal antigen test, and serologic parameters (pepsinogen I and II, H pylori antibody) as surrogate markers of H pylori gastritis and as indicators of gastritis severity. (medscape.com)
- The carbon 13 UBT is based on the detection of the products created when urea is split by the organism. (medscape.com)
- Patients are asked to drink urea (usually with a beverage) labeled with a carbon isotope (carbon 13 or carbon 14). (medscape.com)
- Also, a carbon 13 urea breath test (UBT) is helpful in these patients. (medscape.com)
- Palaeodietary reconstruction using the carbon and nitrogen isotope values of bone and dentine collagen is a well-established method and the biochemical processes involved are well known. (uv.es)
- We present concentration and isotopic profiles of total, size, and polarity fractionated dissolved organic carbon (DOC) from Station ALOHA (A Long-term Oligotrophic Habitat Assessment), an oligotrophic site in the North Pacific Ocean. (whoi.edu)
- In these lessons, we will learn about Isotopes, Isotope Notation, Atomic Mass Unit (amu), and how to calculate the Atomic Mass of an element. (onlinemathlearning.com)
- The following diagrams show the isotopes of chlorine and how to calculate the relative atomic mass. (onlinemathlearning.com)
- In this video, we'll learn about what isotopes are and how to write atomic number and mass number in isotope notation. (onlinemathlearning.com)
- An atom of carbon-12 is taken to have a mass of 12 atomic mass unit (amu). (onlinemathlearning.com)
- How do you determine and calculate isotope abundance when you know the relative atomic mass (also known as atomic weight), as measured in amu or atomic mass numbers? (onlinemathlearning.com)
- If the relative atomic mass of chlorine is 35.45, what is the abundance of each isotope? (onlinemathlearning.com)
- After a certain duration, the concentration of the labeled carbon is measured in the breath. (medscape.com)
- As a result, egg masses produced had carbon isotope ratios in the C3 range of values. (tamu.edu)
- Most importantly, there have been no comparative studies of collagen and calculus isotope values, which are necessary to establish the value of bulk calculus as a source of accurate isotope values. (uv.es)
- Soils dominated by aerobic degradation can be expected to have a clear increase of carbon isotopes (δ13C) with depth, due to preferential release of 12C during aerobic mineralization. (unibas.ch)
- However, few studies have examined the effect of stable isotope ratios on metabolic risk in humans. (ewha.ac.kr)
- Fishes are often utilised in aquatic isotope studies as they structure ecosystems and communities that matter to people, and can cause top-down effects (Kishi et al. (springer.com)
- To date, a limited number of stable isotope studies on fish mucus suggest it has a relatively fast turnover rate. (springer.com)
- Radiotracer studies of bound pesticide residues in soil, plants and food : report of a research co-ordination meeting on isotopic tracer-aided studies of unextractable or bound pesticide residues in soil, plants and food / organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development and held at Neuherberg, 11-15 July 1983. (who.int)
- Quantification, nature and bioavailability of bound 14C-pesticide residues in soil, plants and food : proceedings of the Final Research Co-ordination Meeting on Isotopic Tracer-Aided Studies of Unextractable or Bound Pesticide Residues in Soil, Plants and Food / organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development and held in Gainesville, Florida, from 25 to 29 March 1985. (who.int)
- Results of search for 'au:'Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development. (who.int)
- 4. The carbon isotope ratios of lady beetle adults collected in cotton fields suggested that grain sorghum was a continuous source for H. convergens until many nearby sorghum fields matured and senesced. (tamu.edu)
- 5. When cotton aphid (Aphis gossypii Glover) prey were absent, carbon isotope ratios of beetle populations did not change over time and virtually no egg production by H. convergens was detected. (tamu.edu)
- In isotope notation, you can quickly show how many protons, neutrons, and electrons are in an atom. (onlinemathlearning.com)
- Carbon isotope depth profiles of hummocks indicated a turn from aerobic mineralisation to anaerobic degradation at a peat depth between 4 and 25 cm. (unibas.ch)
- Background: The relationship between stable isotope ratios and dietary protein sources has been reported. (ewha.ac.kr)
- The isotope depth profile of the peat in the water saturated depressions (hollows) at the yet undisturbed mire Storflaket indicated very low to no degradation but increased rates of anaerobic degradation at the Stordalen site. (unibas.ch)
- Marketing and consumer acceptance of irradiated foods : report of the Consultants' Meeting on Marketing, Market Testing and Consumer Acceptance of Irradiated Foods, Vienna, 27 September - 1 October 1982 / organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development. (who.int)
- Use of irradiation as a quarantine treatment of agricultural commodities : final report of a consultants' meeting held in Honolulu, Hawaii, 21-23 November 1983 / organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development. (who.int)
- Nuclear techniques in the study and control of parasitic diseases of livestock : proceedings of the Final Research Co-ordination Meeting on the Use of Nuclear Techniques in the Study and Control of Parasitic Diseases of Farm Animals, held in Vienna from 11 to 14 May 1987 / organized by the Joint FAO/IAEA Division of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development. (who.int)