Reaction photochemical processes. Medical search. Frequent questions

The findings could improve scientists' understanding of light-driven processes such as photosynthesis, smog formation and ozone destruction. (lifeboat.com)
Examples of photochemical processes including photosynthesis, photography, solar energy conversation and atmospheric photochemistry. (bath.ac.uk)
Examples of photochemical reactions are photosynthesis in plant cells and light-induced changes that take place in the eye . (newworldencyclopedia.org)
Excited-state proton transfer reactions are one of the most important classes of photochemical reactions, relevant to energy transfer, photosynthesis and many other important chemical and biological processes. (uh.edu)
RCEL_CERSP The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. (proteopedia.org)
Photoautotrophic organisms (cyanobacteria, algae, green plants) need energy for the production of organic compounds and therefore they employ the energy of light, which they absorb, into process called photosynthesis . (cas.cz)
They affect the photosynthesis, accelerating the process, but intensify the evaporation from the surface of leaves. (pravda.ru)
ABSTRACT---Photosynthesis is a process that occurs in plants, algae and some types of bacteria and that makes use of the sun's energy to generate chemical reactions that transform solar energy into useful energy by combining water and carbon dioxide (CO2) to carbohydrates (sugars) and emit oxygen. (upm.es)

There are geological processes that consume oxygen, so even when biology is pumping it into the environment it doesn't necessarily rise strongly in the atmosphere right away," Anbar said. (livescience.com)
These studies allow the McMahon group to better understand the chemical processes that occur in natural environments, like flames, the atmosphere and space. (wisc.edu)
Light is indisputably at the origin of life on earth, driving all photo-chemical reactions in atmosphere, biological systems, and "man-made" energy related materials. (lu.se)
Once the substance finds itself in the atmosphere, it triggers photochemical reactions, which destroy the ozone screen of the planet. (pravda.ru)
The model predicts substantial production of several species, including HNO₂, HNO₃, NO₃, and N₂O₅, due to chemical reaction within the museum atmosphere. (caltech.edu)
Solvent borne coating compositions typically contain volatile organic compounds (VOC) that are compounds of carbon, which can emit into atmosphere and participate in atmospheric photochemical reactions. (justia.com)
VOCs emitted into atmosphere, such as those emitted from coating compositions during coating manufacturing, application and curing process, can be related to air pollution impacting air quality, participate in photoreactions with air to form ozone, and contribute to urban smog and global warming. (justia.com)

We provide a comprehensive analysis of the photochemical and photophysical pathways of nanocaged RB to better understand how to control the function of RB as a photo-active ROS-therapeutic agent. (aiche.org)
We aim at unravelling a complete picture of photophysical and photochemical processes in these systems. (lu.se)

This reactive species of oxygen causes what's called photochemical transformation, a process in which light and oxidizing materials produce chemical reactions. (newswise.com)

and (4) Implications of long-term ozone effects on community and whole-ecosystem level processes, with an emphasis on crop quality, nutrient cycling and carbon sequestration, and biodiversity of pastures and rangelands. (usda.gov)
Major limitations in current knowledge exist in several areas: (1) Modelling of ozone transfer and specifically stomatal ozone uptake under variable environmental conditions, using robust and well-validated dynamic models that can be linked to large-scale photochemical models lack coverage. (usda.gov)
2) Processes involved in the initial reactions of ozone with extracellular and cellular components after entry through the stomata, and identification of key chemical species and their role in detoxification require additional study. (usda.gov)
4) Implications of long-term ozone effects on community and whole-ecosystem level processes, with an emphasis on crop quality, element cycling and carbon sequestration, and biodiversity of pastures and rangelands require renewed efforts. (usda.gov)
Indoor reactions are initiated mainly by ozone, a pollutant, which is transported from the outdoor environment into the indoor environment by building ventilation. (cdc.gov)
NIOSH research has shown that when combined with ozone, one of the common components of pine oil cleaners, alpha-terpineol, transforms into many oxygenated organic compounds in both the gas-phase and on surface reactions creating new products potentially harmful to those exposed. (cdc.gov)

The authors suggest a complex and interdependent dance between biological and geological processes can explain the gap. (livescience.com)
If the biological interpretation is correct, some process must have kept the oxygen being produced in check for millions of years, up until the Great Oxidation Event. (livescience.com)
Anbar suggests non-biological processes could play a role. (livescience.com)
Seeing is believing," has been taken to heart by researchers as they strive to develop microscopes that will reveal biological structures and processes with increased clarity and detail. (sciencedaily.com)
This has severely limited the ability to observe biological processes with more than five interacting components," said Behrouz Shabestari, Ph.D., director of the NIBIB program in Optical Imaging and Spectroscopy, "making it impossible to observe complex systems such as molecular pathways that result in tumor formation or patterns of neuronal activation in the brain. (sciencedaily.com)
The association pathway from monomer to oligomer is critical in a range of biological processes and thus it is of a vital importance to elucidate both atomic-resolution structures of intermediates along the pathway as well as the structure of the final state. (lu.se)

A systematic study of 1,2-diamines indicates that the quantum efficiencies of the reaction are highly dependent on the reaction conditions (solvent, type of sensitizer, cosensitization, etc.) and structural considerations of the molecules being studied. (elsevierpure.com)
The photochemical cis-trans isomerization of free stilbene molecules follows a hula-twist pathway. (mpg.de)
Normally, a reaction (not just a photochemical reaction) occurs when the molecules involved gain the activation energy necessary to undergo change. (newworldencyclopedia.org)
Photochemical tissue bonding (PTB) of wounds and surgical incisions relies on the use of photosensitive molecules and light to induce the formation of covalent linkages in collagenous tissue. (aiche.org)
The cartoon illustrates why some molecules undergo proton transfer reactions when exposed to radiation by light. (uh.edu)
Proton and electron transfer reactions provide a channel for molecules in the excited-state to relieve antiaromaticity, and this underlies the photostability of DNA base pairs. (uh.edu)
The process wouldn't be possible without photo initiators, which are molecules in the ink that absorb UV light as a form of energy to initiate the curing reaction. (inkcups.com)

1,2-aminoalcohols and 1,2-diamines undergo analogous fragmentation reactions although they show quite different reactivities. (elsevierpure.com)
The primary photoproducts resulting from the C-N and C-C ring-opening reactions were also found to undergo further photochemical decarbonylation or decarboxylation reactions. (conicet.gov.ar)
It is known to undergo violent reactions with aniline, 3-bromopropyne, sodium hydroxide/alcohol solutions, sodium methoxide, and propargyl bromide. (medscape.com)

We have examined and revealed the effects of localized surface plasmon resonance of metal nanopaparticels on molecular photochemical processes by conventional and single particle spectroscopies. (nii.ac.jp)
Mavrikakis was recognized with the Gabor A. Somorjai Award for Creative Research in Catalysis for creatively combining computer-based techniques that simulate molecular structure and reactivity with experiments that provide insight into the nature of the active site during catalytic reactions and help identify improved catalysts. (wisc.edu)
By enabling both time resolution and structural detail Time-Resolved Small Angle X-ray/Neutron Scattering (TR-SAXS/TR-SANS) is uniquely suited to interrogate complex self-assembly reactions and to provide a molecular understanding of self-assembly pathways. (lu.se)

The devices using Electro-optic (EO) polymers has been demonstrated for high-speed modulators and switching because of its low dispersion, coating quality, inexpensive process. (arizona.edu)
and (3) optical-waveguiding instability due to photochemical reaction in EO polymers. (arizona.edu)

In an intramolecular [2+2]-photocycloaddition reaction enantiomeric excesses up to 92% ee were obtained with these polymer-bound chiral templates and the polymer was recovered in almost quantitative yield. (tum.de)

In general, the cation radicals of 1,2-diamines fragment more efficiently than those of aminoalcohols and the reactions are not dependent on the basicity of the reduced acceptor counterion species. (elsevierpure.com)
Kinetic steady-state analysis showed that dimeric species are not as effective as monomeric RB for the photochemical ROS-mediated therapy. (aiche.org)
In turn, this process generates elevated levels of reactive oxygen species, which damage the DNA causing numerous chromosomal abnormalities. (chemistryviews.org)
Is any photochemical reaction going on so that oxygen species which are reactive are formed. (chemistryviews.org)
The excited states created by UV absorption are endowed with mechanisms of deactivation which are of major importance for the photochemical stability of these species. (cea.fr)
The generation of singlet oxygen species, labeled type 2 photochemical reactions, are believed to predominate in photodynamic therapy. (medscape.com)

When UV inks are exposed to UV light rays, a photochemical reaction occurs which causes the UV ink to cure instantly at low energy levels. (inkcups.com)

Dark Intermediate States in Photochemical Cis-Trans Isomerization and Pericyclic Reactions. (mpg.de)

Several examples of photoinduced electron transfer initiated cation radical carboncarbon bond fragmentation reactions are reported. (elsevierpure.com)
Only this time, the article focuses on proton and electron transfer reactions in the photoexcited states of DNA base pairs. (uh.edu)
Cartoon shows the DNA base pairs get rid of excited-state antiaromaticity by a proton-coupled electron transfer reaction. (uh.edu)
Time resolved information about these processes can be obtained using free electron lasers or attosecond light sources. (lu.se)
Of particular interest is energy and electron transfer in photosynthetic light-harvesting complexes and reaction centers, which demonstrate remarkable efficiency and robustness. (lu.se)

The following graphic reflects the process of smog formation. (aljazeera.com)

Photochemical processes occur when atomic nuclei and their electrons take on different configurations after absorbing a photon. (lifeboat.com)
The absorption of a photon of light by a reactant molecule may permit a reaction to occur not just by bringing the molecule to the necessary activation energy, but also by changing the symmetry of the molecule's electronic configuration, enabling an otherwise inaccessible reaction path. (newworldencyclopedia.org)
And because the process does not occur in the dark, the amount of sunlight a water body receives also affects reactions. (newswise.com)

Some of these reactions are guided by a quantum phenomenon called a conical intersection, where the potential energy surfaces that describe a molecule in its ground state and in its excited state converge. (lifeboat.com)

In: Femtochemistry VII: Fundamental Ultrafast Processes in Chemistry, Physics, and Biology, S. 96 - 104 (Hg. (mpg.de)
On the atomic scale level, we can describe these photo-chemical reactions, through a multitude of elementary processes occurring on the ultrafast time scale (from sub femtosecond to picosecond) where the initial energy/light harvesting process is followed by energy conversion and transport processes. (lu.se)
The majority of these processes are ultrafast and provide a rapid and efficient way to dissipate the electronic energy into vibration, thus avoiding photochemical reactions. (cea.fr)

Donkers RL, Stringle DLB, Workentin MS. ( 2001 ) 7 Reaction mechanisms. (academictree.org)
2001 ) ChemInform Abstract: Reaction Mechanisms. (academictree.org)
2000 ) 9 Reaction mechanisms Annual Reports Section "B" (Organic Chemistry) . (academictree.org)
Daisuke Minakata, associate professor of civil, environmental and geospatial engineering at Michigan Tech, developed a comprehensive reactive activity model that shows how singlet oxygen's reaction mechanisms perform against a diverse group of contaminants and computes their half-life in a natural aquatic environment. (newswise.com)
Catalysis helps create approximately 80 percent of the products consumers encounter in their lives, but the reaction mechanisms of numerous catalysts, even those employed in industry for many years, are still poorly understood. (wisc.edu)
Hermans' group strives to better understand complex reaction mechanisms and to design energy efficient processes, both of which are essential for sustainable chemistry and catalysis. (wisc.edu)

The first law of photochemistry, known as the Grotthuss-Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place. (newworldencyclopedia.org)
The second law of photochemistry, the Stark-Einstein law, states that for each photon of light absorbed by a chemical system, only one molecule is activated for a photochemical reaction. (newworldencyclopedia.org)

A comparison of thermal and photochemical processes. (academictree.org)
In addition, the influence of homogeneous photolytic and thermal chemical reactions is computed for gases that are present in the photochemical smog system. (caltech.edu)
This effect is photochemical rather than thermal or structural [8]. (who.int)

The Cu(I)I-Pyox complex efficiently catalyzes a first-in-class conjugate addition affording a range of complex, functionalized isocyanoalkanes that are otherwise challenging to synthesize while laying a foundation for catalytic reactions that maintain the isocyanide group. (bvsalud.org)

I use darkroom processes to produce outcomes that allude to, but don't truly describe, color in the natural world. (canyoncinema.com)
Specifically, Yoon's research group designs catalysts that promote specific reaction outcomes in photochemical synthesis. (wisc.edu)

Despite the ever-increasing need to understand these energy conversion and transport processes in many fields of Physics, Chemistry, and Biology, many challenges must be addressed due to the multiscale nature of the problem - from atomic to nanoscopic length and time scale. (lu.se)

My methods allow me to avoid many conventional industrial processes and vastly expand the boundaries of common color palettes. (canyoncinema.com)
It eliminates the need for the conventional primary, secondary, and tertiary processes, resulting in maximum colour removal, and meets the inland water discharge standards. (thehindu.com)
The technology has resulted in the recuperation of 50% of the treatment cost incurred from conventional processes for water treatment (especially due to the high cost of sludge disposability) in the water-scarce regions of Rajasthan. (thehindu.com)

We report on the unexpected structural changes caused by substitution of acidic amino acids in the Q(B) binding pocket of the bacterial photosynthetic reaction center by alanines. (proteopedia.org)
The observed rearrangements in the structure of the AA reaction center establish a new balance between charged residues of an interactive network near Q(B). This structurally and electrostatically altered complex forms the basis for future understanding of the structural basis for proton transfer in active reaction centers which retain the alanine substitutions but carry a distant compensatory mutation. (proteopedia.org)
Particular emphasis is placed on classifications based on formal structural change and on reaction mechanism, and on the role of classifications within computerized reaction retrieval systems. (researchgate.net)

Environmentally friendly process could lead to the sustainable production of bioactive compounds and advanced biofuels. (chemicalprocessing.com)
This includes gas-liquid reactions, photochemical and electrochemical transformations, and chemistries utilizing hazardous compounds, extreme reaction conditions and multistep reaction sequences. (tue.nl)
Knowing that this was the case is a huge help in understanding the processes that formed compounds in the early solar system. (space.com)

Part (iv) Radical and radical ion reactions Annual Reports Section "B" (Organic Chemistry) . (academictree.org)
Radical and Radical Ion Reactions Cheminform . (academictree.org)

Quantum computing has provided new insights into a fundamental aspect of photochemical reactions that has previously proven difficult to study. (lifeboat.com)
The structure, preferred conformers, vibrational spectrum, and photochemical behavior of the novel azirine, methyl 2-chloro-3-methyl-2H-azirine-2-carboxylate (MCMAC) were investigated in low-temperature matrixes and in the neat solid amorphous state by infrared spectroscopy and quantum-chemical calculations. (conicet.gov.ar)

The rate constants for indirect photolysis via reaction of the reaction mass of 2 -piperazin-1 -ylethanol, piperazine-1,4 -diethanol and piperazine (50, 25 and 25 %) with OH radicals was estimated for the major components. (europa.eu)
New data concerning the structure and photochemical reactivity of strong Fe(III) binding ligands (siderophores) produced by pelagic marine bacteria suggest that direct photolysis via ligand-to-metal charge transfer reactions may be an important mechanism for the production of reduced, biologically available iron (Fe[II]) in surface waters. (bioone.org)

With the half-life calculations established by Minakata's model, the research team plans to further study the byproducts produced by singlet oxygen/chemical reactions - with an eye toward predicting whether the byproducts themselves will be toxic. (newswise.com)

The current three-stage treatment process for wastewater consisting of primary, secondary, and tertiary treatment is unable to treat toxic industrial wastewater. (thehindu.com)

Photodynamic therapy (PDT) involves the use of photochemical reactions mediated through the interaction of photosensitizing agents, light, and oxygen for the treatment of malignant or benign diseases. (medscape.com)

Most soft X-ray experiments are performed at synchrotron radiation facilities in order to characterize elementary processes. (lu.se)

The amino acid substitutions in the L212Ala-L213Ala mutant reaction center ("AA") were known to affect the delivery of protons after the light-induced generation of Q(B)(-), which renders the AA strain incapable of photosynthetic growth. (proteopedia.org)

Describe modern instrumental methods for photochemical investigation. (bath.ac.uk)

The energy of the SWIR laser light (355 nm) causes a photochemical reaction on the processed product. (photonics.com)
In the case of photochemical reactions, light provides the activation energy. (newworldencyclopedia.org)
The absorption of light by a reactant elevates the reactant to a higher energy state, or excited state, and the process is called "photoexcitation. (newworldencyclopedia.org)

La fotosíntesis es un proceso que se da en plantas, algas y algunos tipos de bacteria y que hace uso de la energía del sol para generar reacciones químicas que transforman la energía solar en energía útil mediante la combinación de agua y el dióxido de carbono (CO2) para formar carbohidratos (azúcares) y emitir oxígeno. (upm.es)
Gracias a esta reacción, la energía solar es transformada en energía química cuando esta se proyecta sobre la superficie de un catalizador. (upm.es)

In recent years, progress has been made toward understanding the role of biologically produced organic ligands in controlling the speciation and photochemical redox cycling of iron in ocean surface waters. (bioone.org)

The structure of a mutant photosynthetic reaction center shows unexpected changes in main chain orientations and quinone position. (proteopedia.org)
Pokkuluri PR, Laible PD, Deng YL, Wong TN, Hanson DK, Schiffer M. The structure of a mutant photosynthetic reaction center shows unexpected changes in main chain orientations and quinone position. (proteopedia.org)

Iron is a limiting nutrient for primary production in marine systems, and photochemical processes play a significant role in the upper ocean biogeochemical cycling of this key element. (bioone.org)

It is a direct replacement of the existing treatment plant processes and consists of a low-cost solution of dye adsorption on acid-modified soil, followed by a photochemical reaction step within a photocatalytic visible light filter and a unique carbon and PAN (polyacrylonitrile) nano-mat fibre filtration process. (thehindu.com)

Smog results when photochemical reaction takes place between air pollutants from crop burning, vehicles and others sources, and sunglight and heat. (aljazeera.com)

Fate and transport are interdependent processes. (cdc.gov)

Underlying all these advances are chemical engineering principles that enable chemical processes to be carried out under perfectly controlled reaction conditions. (tue.nl)

McMahon's research program explores basic aspects of organic chemistry in the context of harsh reaction conditions, which include extreme temperatures and electrical discharges, such as lightning strikes. (wisc.edu)
A comprehensive analysis of the overall chemistry of isomerase reactions based on bond changes, reaction centres and substrates and products revealed that isomerase reactions are chemically diverse and difficult to classify using a hierarchical system. (researchgate.net)

Possible transport processes that can carry a contaminant away from its source. (cdc.gov)

The analysis of a vertical isothermal flat plate in natural convection flow shows that, for this flow regime, thermophoresis is an important particle transport process within the boundary layer adjacent to the surface, effectively repelling particles larger than approximately 0.1 µm in diameter if the surface is even a few degrees K warmer than the nearby air. (caltech.edu)

2006 ) Reaction of alkenes with hydrogen-terminated and photooxidized silicon surfaces. (academictree.org)

Our proposed mechanism integrates thermodynamic and reaction kinetics of the RB photo-oxidation reaction via the monitoring of the photochemical reactions with multiple spectroscopic techniques in tandem. (aiche.org)

A photochemical reaction may be thought of as a reaction ignited by the absorption of light. (newworldencyclopedia.org)

Specimens were processed for ultrastructural and light microscopic investigations. (who.int)
These highly sensitive and specific drt-PCR assays do not require DNA extraction and thereby reduce the time, cost, and handling required to process CSF specimens. (cdc.gov)
Furthermore, triplex drt-PCR assays combine the detection of three serotypes in a single reaction, further improving testing efficiency, which is critical for laboratories that process high volumes of Hi specimens for surveillance and diagnostic purposes. (cdc.gov)

Photoredox catalysis is an environmentally friendly process that harnesses the power of light to accelerate reactions unable to be performed by traditional chemical methods. (wisc.edu)
The use of light to enhance the effects of the bleaching gel is recent, and a study have pointed out that this procedure can accelerate dental bleaching process (4), but more recent publications indicate that the benefit of the additional use of light is limited (5). (bvsalud.org)

In addition, Q(B) is found mainly in the binding site that is proximal to the iron-ligand complex (closest to Q(A)) as opposed to its distal binding site (furthest from Q(A)) in the structure of the wild-type reaction center. (proteopedia.org)
Several recommendations to improve the description of complex biochemical reaction data in the EC classification were proposed. (researchgate.net)
These properties make 2DES the method of choice when exploring the light-triggered processes in complex systems. (lu.se)

Karas uses computer simulations to study photochemical processes under the advisement of College of Natural Sciences and Mathematics assistant professor Judy Wu. (uh.edu)
In this study, I mention theoretical backgrounds, properties, and then process for device fabrication to solve these precious all polymeric approaches. (arizona.edu)

Researchers from leading institutions collaborate on a dual-active site catalyst comprising copper and tungsten, which enables an efficient and selective conversion process and. (chemicalprocessing.com)
The light activation units most used at present are the quartz-halogen-tungsten (QHT), argon lasers, plasma arc and light emitting diodes (LEDs), which have the advantage of promoting photo-chemical reactions and later selective and controlled heating of only the gel, instead of the entire dental structure (5). (bvsalud.org)

After evaporation or exposure to air, the reaction mass will be rapidly degraded by photochemical processes. (europa.eu)

The focus here lies on the development of more sustainable processes to lower the E-factor. (tue.nl)

The carbon capture and conversion process uses a switchable dual-function material consisting of nanoparticles to perform reactions. (chemicalprocessing.com)
This completely modified treatment process consisting of the primary dosing step, followed by the sand filtration step, another AOP and subsequent carbon filtration step. (thehindu.com)

This limits the path that the reaction can take and affects the reaction outcome. (lifeboat.com)

I make a conscious decision to begin with film based on that medium's unduplicable and capricious reaction to photo-chemical stimuli. (canyoncinema.com)

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