TY - JOUR. T1 - Simultaneous measurement of arterial transit time, arterial blood volume, and cerebral blood flow using arterial spin-labeling in patients with Alzheimer disease. AU - Yoshiura, Takashi. AU - Akio, Hiwatashi. AU - Yamashita, Koji. AU - Ohyagi, Y.. AU - Monji, A.. AU - Takayama, Yukihisa. AU - Nagao, E.. AU - Kamano, H.. AU - Noguchi, T.. AU - Honda, Hiroshi. PY - 2009/8/1. Y1 - 2009/8/1. N2 - BACKGROUND AND PURPOSE: Cerebral hemodynamics abnormality in Alzheimer disease (AD) is not fully understood. Our aim was to determine whether regional hypoperfusion due to AD is associated with abnormalities in regional arterial blood volume (rABV) and regional arterial transit time (rATT) as measured by quantitative arterial spin-labeling (ASL) with multiple-delay time sampling. MATERIALS AND METHODS: Nineteen patients with AD (9 men and 10 women; mean age, 74.5 ± 8.6 years) and 22 cognitively healthy control subjects (11 men and 11 women; mean age, 72.8 ± 6.8 years) were studied by using ...

X- and W-band EPR spectra, at room and low temperatures, are reported for nitroxide spin labels attached to cysteine residues selectively introduced into two proteins, the DNase domain of colicin-E9 and its immunity protein, Im9. The dynamics of each site of attachment on the individual proteins and in the tight DNase-Im9 complex have been analysed by computer simulations of the spectra using a model of Brownian dynamics trajectories for the spin label and protein. Ordering potentials have been introduced to describe mobility of labels restricted by the protein domain. Label mobility varies with position from completely immobilised, to motionally restricted and to freely rotating. Bi-modal dynamics of the spin label have been observed for several sites. We show that W-band spectra are particularly useful for detection of anisotropy of spin label motion. On complex formation significant changes are observed in the dynamics of labels at the binding interface region. This work reveals multi-frequency EPR

Delayed cerebral ischaemia (DCI) is the major cause of mortality and morbidity following aneurysmal subarachnoid haemorrhage (SAH). Recent experimental evidence from animal models has highlighted the need for non-invasive and robust measurements of brain tissue perfusion in patients in order to help understand the pathophysiology underlying DCI. Quantitative, serial, whole-brain cerebral perfusion measurements were obtained with pseudo-continuous arterial spin labelling (PCASL) magnetic resonance imaging (MRI) in six SAH patients acutely following endovascular coiling. This technique requires no injected contrast or radioactive isotopes. MRI scanning was well tolerated. Artefact from endovascular coils was minimal. PCASL MRI was able to detect time-dependent and patient-specific changes in voxel-wise and regional cerebral blood flow. These changes reflected changes in clinical condition. Data obtained in healthy controls using the same experimental protocol confirm the reliability and reproducibility of

PURPOSE: In vessel-encoded pseudo-continuous arterial spin labeling (ve-pCASL), vessel-selective labeling is achieved by modulation of the inversion efficiency across space. However, the spatial transition between the labeling and control conditions is rather gradual, which can cause partial labeling of vessels, reducing SNR-efficiency and necessitating complex postprocessing to decode the vessel-selective signals. The purpose of this study is to optimize the pCASL labeling parameters to obtain a sharper spatial inversion profile of the labeling and thereby minimizing the risk of partial labeling of untargeted arteries. METHODS: Bloch simulations were performed to investigate how the inversion profile was influenced by the pCASL labeling parameters: the maximum (Gmax ) and mean (Gmean ) labeling gradient were varied for ve-pCASL with unipolar and bipolar gradients. The findings in the simulation study were subsequently confirmed in an in vivo volunteer study. Moreover, conventional and optimized

Arterial Spin Labeling (ASL) is a non-invasive, non-contrast, perfusion imaging technique which is inherently SNR limited. It is, therefore, important to carefully design scan protocols to ensure accurate measurements. Many pseudo-continuous ASL (PCASL) protocol designs have been proposed for measuring cerebral blood flow (CBF), but it has not yet been demonstrated which design offers the most accurate and repeatable CBF measurements. In this study, a wide range of literature PCASL protocols were first optimized for CBF accuracy and then compared using Monte Carlo simulations and in vivo experiments. The protocols included single-delay, sequential and time-encoded multi-timepoint protocols, and several novel protocol designs, which are hybrids of time-encoded and sequential multi-timepoint protocols. It was found that several multi-timepoint protocols produced more confident, accurate, and repeatable CBF estimates than the single-delay protocol, while also generating maps of arterial transit time. Of

Bax is a Bcl-2 protein crucial for apoptosis initiation and execution, whose active conformation is only partially understood. Dipolar EPR spectroscopy has proven to be a valuable tool to determine coarse-grained models of membrane-embedded Bcl-2 proteins. Here we show how the combination of spectroscopically distinguishable nitroxide and gadolinium spin labels and Double Electron-Electron Resonance can help to gain new insights into the quaternary structure of active, membrane-embedded Bax oligomers. We show that attaching labels bulkier than the conventional MTSL may affect Bax fold and activity, depending on the protein/label combination. However, we identified a suitable pair of spectroscopically distinguishable labels, which allows to study complex distance networks in the oligomers that could not be disentangled before. Additionally, we compared the stability of the different spin-labeled protein variants in E. coli and HeLa cell extracts. We found that the gem-diethyl nitroxide-labeled Bax

A pulsed EPR saturation-recovery method has been used to measure spin-lattice relaxation times (T 1) for aminoxyl spin labels in cardiolipin bilayers, with and without cytochrome c. The relaxation time for each spin label was determined at various positions in the bilayer, which included the bilayer surface and three positions within the hydrophobia interior in the membrane, as well as a position close to the glycerol backbone of phospholipids in the bilayer. A dynamic profile for the hydrocarbon chains in bilayers was found in agreement with results from other techniques. On addition of cytochrome c to cardiolipin bilayers, changes in the spin-lattice relaxation time and order parameter were observed around the unsaturated region in the cardiolipin acyl chains. Supported by complementary lineshape analysis, these effects were interpreted as changes in the molecular dynamics around the double bonds in the acyl chains of cardiolipin bilayers, induced upon the binding of cytochrome

Arterial spin labeling (ASL) sequences that incorporate multiple postlabeling delay (PLD) times allow estimation of when arterial blood signal arrives within a region of interest. Sequences that account for such variability may improve the reliability of ASL and therefore make the technique well suited for future clinical and experimental investigations of cerebral perfusion. This study assessed the within- and between-session reproducibility of an optimized pseudo-continuous ASL (pCASL) functional magnetic resonance imaging (FMRI) sequence that incorporates multiple postlabeling delays (multi-PLD pCASL). Healthy subjects underwent four identical scans separated by 30 minutes, 1 week, and 1 month using multi-PLD pCASL to image absolute perfusion (cerebral blood flow (CBF) and arterial arrival time (AAT)) during both rest and a visual-cued motor task. We show good test-retest reliability, with strong consistency across subjects and sessions during rest (inter-session within-subject coefficient of

Arterial spin labeling (ASL) sequences that incorporate multiple postlabeling delay (PLD) times allow estimation of when arterial blood signal arrives within a region of interest. Sequences that account for such variability may improve the reliability of ASL and therefore make the technique well suited for future clinical and experimental investigations of cerebral perfusion. This study assessed the within- and between-session reproducibility of an optimized pseudo-continuous ASL (pCASL) functional magnetic resonance imaging (FMRI) sequence that incorporates multiple postlabeling delays (multi-PLD pCASL). Healthy subjects underwent four identical scans separated by 30 minutes, 1 week, and 1 month using multi-PLD pCASL to image absolute perfusion (cerebral blood flow (CBF) and arterial arrival time (AAT)) during both rest and a visual-cued motor task. We show good test-retest reliability, with strong consistency across subjects and sessions during rest (inter-session within-subject coefficient of

article{f3c821e1-f0ea-4245-984f-e7d72221cfcf, abstract = {,p,Apolipoprotein A-I (apoA-I) is the major protein constituent of high density lipoprotein (HDL) and plays a central role in phospholipid and cholesterol metabolism. This 243-residue long protein is remarkably flexible and assumes numerous lipid-dependent conformations. Consequently, definitive structural determination of lipid-free apoA-I in solution has been difficult. Using electron paramagnetic spectroscopy of site-directed spin labels in the N-terminal domain of apoA-I (residues 1-98) we have mapped a mixture of secondary structural elements, the composition of which is consistent with findings from other in-solution methods. Based on side chain mobility and their accessibility to polar and non-polar spin relaxers, the precise location of secondary elements for amino acids 14-98 was determined for both lipid-free and lipid-bound apoA-I. Based on intermolecular dipolar coupling at positions 26, 44, and 64, these secondary structural ...

TY - JOUR. T1 - Probing the structure of the mechanosensitive channel of small conductance in lipid bilayers with pulsed electron-electron double resonance. AU - Ward, Richard. AU - Pliotas, Christos. AU - Branigan, Emma. AU - Hacker, Christian. AU - Rasmussen, Akiko. AU - Hagelueken, Gregor. AU - Booth, Ian R. AU - Miller, Samantha. AU - Lucocq, John. AU - Naismith, James H. AU - Schiemann, Olav. N1 - Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.. PY - 2014/2/18. Y1 - 2014/2/18. N2 - Mechanosensitive channel proteins are important safety valves against osmotic shock in bacteria, and are involved in sensing touch and sound waves in higher organisms. The mechanosensitive channel of small conductance (MscS) has been extensively studied. Pulsed electron-electron double resonance (PELDOR or DEER) of detergent-solubilized protein confirms that as seen in the crystal structure, the outer ring of transmembrane helices do not pack against the pore-forming helices, ...

Interspin distances between 0.8 nm and 2.0 nm can be measured through the dipolar broadening of the continuous wave (cw) EPR spectrum of nitroxide spin labels at X-band (9.4 GHz, 0.35 T). We introduce Gd3+ as a promising alternative spin label for distance measurements by cw EPR above 7 Tesla, where the |−1/

BACKGROUND AND PURPOSE: Perfusion-weighted imaging is used to select patients with acute ischemic stroke for intervention, but knowledge of cerebral perfusion can also inform the understanding of ischemic injury. Arterial spin labeling allows repeated measurement of absolute cerebral blood flow (CBF) without the need for exogenous contrast. The aim of this study was to explore the relationship between dynamic CBF and tissue outcome in the month after stroke onset. METHODS: Patients with nonlacunar ischemic stroke underwent ≤5 repeated magnetic resonance imaging scans at presentation, 2 hours, 1 day, 1 week, and 1 month. Imaging included vessel-encoded pseudocontinuous arterial spin labeling using multiple postlabeling delays to quantify CBF in gray matter regions of interest. Receiver-operator characteristic curves were used to predict tissue outcome using CBF. Repeatability was assessed in 6 healthy volunteers and compared with contralateral regions of patients. Diffusion-weighted and T2-weighted

MATERIALS AND METHODS: The relationship between the presence of collateral vessels on arterial spin-labeling MR imaging and DSA was compared with blood oxygen level-dependent MR imaging measures of hypercapnic cerebrovascular reactivity in patients with symptomatic intracranial stenosis (n = 18). DSA maps were reviewed by a neuroradiologist and assigned the following scores: 1, collaterals to the periphery of the ischemic site; 2, complete irrigation of the ischemic bed via collateral flow; and 3, normal antegrade flow. Arterial spin-labeling maps were scored according to the following: 0, low signal; 1, moderate signal with arterial transit artifacts; 2, high signal with arterial transit artifacts; and 3, normal signal. ...

abdomen abdominal accomplished according achieved acquisition adjusts agents allows always analyzed applications arterial artifacts automated automatically avoided background bandwidth basic behavior best blood bolus brain broader calculations clinical continuous contrast control count counts covers crossing custom delay described describing difficult distinct distribution duration endogenous equation equations especially excitation exogenous expected experiment fitted fitting fluctuations framework frequent ghosting good gray guess healthy histogram implemented initial introduced introduces inversion label labeled labeling larger leading like liver longitudinal magnetization major make matrix measure measured might minimized minutes model modification must note null offline online optimal optimization optimized organ organs part perfusion pipeline pixel post potentially practice prior procedure process proposed pseudo pulse pulses quality quantify readout reconstructed recovery reduces related ...

Spin Labels: Molecules which contain an atom or a group of atoms exhibiting an unpaired electron spin that can be detected by electron spin resonance spectroscopy and can be bonded to another molecule. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed)

Glycerol and polymyxin have been shown by X-ray diffraction to induce interdigitated bilayers in phosphatidylcholine (PC) and phosphatidylglycerol (PG), respectively (McDaniel, R.V., et al. (1983) Biochim. Biophys. Acta 731, 97-108; Ranck, J.-L. and

Finally, we found that DC sensing of HIV-1 and HIV-2 required the DNA sensor cGAS. Treatment consisted of viagra without prescription two 35-day cycles of combination chemotherapy with CPT-11 and UFT. Nerve regression and sprouting were found in animals chronically paralysed with curare over several weeks as well as in untreated frogs (winter and summer frogs, laboratory frogs, fed and unfed). However, environmental change may also reconfigure multispecies interactions when both species composition and phenology remain intact. Arterial spin-labeling MR imaging is now acknowledged for the noninvasive quantification of cerebral blood flow.. Structural and functional basis for JAK3-deficient severe combined immunodeficiency. Person-mean centering was applied to psychological factors to disaggregate between- and within-individual association. In this experiment, we investigated the changes in serum levels of soluble RANKL (sRANKL), OPG, IL-6, and IL-6sR in patients with glucocorticoid-induced ...

Author: Erilov, D. A. et al.; Genre: Journal Article; Published in Print: 2005-06-23; Open Access; Title: Water concentration profiles in membranes measured by ESEEM of spin-labeled lipids

The biomembrane is postulated as the initial target when Platinum(II) complexes attack cells. In this work, a spin-labeling ESR technique has been used to study the effects of cis-DCDP, cis-DBDP, cis-DIDP, trans-DCDP, and cis-DADP on the permeability of human erythrocyte membrane. We monitored the reduction processes of the ESR signal of a nitroxide spin label, (TEMPO), which leaks out through the membrane and is reduced by the external ascorbate. Our results indicate that cisplatin and its analogues can enhance the permeability of membranes to small moieties such as TEMPO and ascorbate, and the differences between these compounds are related to features of the leaving group. In addition, changes in the order parameter of 5DS spin label in membrane indicate that hydrolysis of these Pt(II) complexes result in membrane damage.. ...

Roessler MM, King MS, Robinson AJ, Armstrong FA, Harmer J & Hirst J (2010) Direct assignment of EPR spectra to structurally defined iron-sulfur clusters in complex I by double electron-electron resonance. Proc Natl Acad Sci U S A 107, 1930-5 ...

G protein-coupled receptors (GPCRs) relay diverse extracellular signals into cells by catalyzing nucleotide release from heterotrimeric G proteins, but the mechanism underlying this quintessential molecular signaling event has remained unclear. Here we use atomic-level simulations to elucidate the nucleotide-release mechanism. We find that the G protein α subunit Ras and helical domains-previously observed to separate widely upon receptor binding to expose the nucleotide-binding site-separate spontaneously and frequently even in the absence of a receptor. Domain separation is necessary but not sufficient for rapid nucleotide release. Rather, receptors catalyze nucleotide release by favoring an internal structural rearrangement of the Ras domain that weakens its nucleotide affinity. We use double electron-electron resonance spectroscopy and protein engineering to confirm predictions of our computationally determined mechanism. ...

Tkach, I.; Pornsuwan, S.; Höbartner, C.; Wachowius, F.; Sigurdsson, S.; Baranova, T. Y.; Diederichsen, U.; Sicoli, G.; Bennati, M.: Orientation selection in distance measurements between nitroxide spin labels at 94 GHz EPR with variable dual frequency irradiation. Physical Chemistry Chemical Physics 15 (10), S. 3433 - 3437 (2013 ...

Over the last 25 years one of us (WKS) has been investigating physical properties of lipid bilayer membranes. In 1991 a group led by WKS was organized into the Laboratory of Structure and Dynamics of Biological Membranes, the effective member of which is AW. Using mainly the electron paramagnetic resonance (EPR) spin-labeling method, we obtained unexpected results, which are significant for the better understanding of the functioning of biological membranes. We have developed a new pulse EPR spin-labeling method for the detection of membrane domains and evaluation of lipid exchange rates. This review will be focused on our main results which can be summarized as follows: (1) Unsaturation of alkyl chains greatly reduces the ordering and rigidifying effects of cholesterol although the unsaturation alone gives only minor fluidizing effects, as observed by order and reorientational motion, and rather significant rigidifying effects, as observed by translational motion of probe molecules; (2) ...

To summarize the main findings of the present study, ASL and DSC PWI provided largely consistent results in delineating hypoperfusion lesions in AIS. The most consistent associations, as demonstrated by both subjective ratings and quantitative vascular territory analyses, were between ASL CBF and DSC Tmax, MTT, and CBFr0 measures, which also demonstrated the highest interrater reliability. ASL techniques are limited by the relatively short tracer half-life determined by the T1 of blood. Even with advanced pseudocontinuous ASL and 3-dimensional gradient and spin echo readout, the postlabeling delay time is typically ,3 seconds in ASL experiments at field strengths of ≤3 T. In the present study, a postlabeling delay of 2 seconds was used in pseudocontinuous ASL scans as a tradeoff between maintaining adequate diagnostic quality at the same time as allowing sufficient delay to visualize tissue perfusion. Our findings suggest that hypoperfusion lesions on ASL CBF maps may reflect delayed transit ...

Part I; DNA and Higher Order Cell Systems The effects of a range of nitroxides on the radiation damage routes in frozen aqueous DNA have been studied by comparison with nitroxide free systems. The results show that nitroxides affect the yield of both primary and secondary radicals in this system. The differences between the effects of the nitroxides studied are attributed to steric effects. A range of spin-labelled polyanmionium cations (PACs) have been used to probe the motion of PACs when they are complexed with DNA. The results suggest that PACs experience virtually free movement along the DNA backbone. The effects of one of these spin-labelled PACs on irradiated frozen aqueous DNA have been studied. The results show that constraining the nitroxide group to be close to the DNA by attaching it to a PAC increases the effect of the nitroxide on irradiated DNA at low temperatures. At higher temperatures the spin-labelled PAC is less effective and it is proposed that this is due to less efficient ...

The second panel was titled Breaking the barriers of membrane protein expression and labeling and was moderated by Robert Nakamoto. The panel included Chris Ahern, Jim Bowie, Volker Dötsch and Shohei Koide. Discussion focused on three topics: the optimal nitroxide spin probe for monitoring protein dynamics and DEER distance measurements, how to incorporate such a probe into the protein targets, and cell free synthesis of target proteins. The optimal nitroxide spin probe would be connected to the backbone by only a β carbon. Such a label can be introduced using chemical synthesis, but because most of our proteins are too large, methods for bio-incorporation of unnatural amino acid are preferred. Cell free biosynthesis systems such as those developed in the laboratory of Volker Dötsch, Goethe University, and Chris Ahern, University of British Columbia, may provide the best approaches. The Protein Core labs will explore methods for charging the non-sense tRNA by evolved tRNA synthetases or a ...

1.CVP=RAP=RVEDP CVP: Central Venous Pressure, RAP: Right Atrial Pressure, RVEDP: Right-ventricular End-diastolic Pressure 2.PAWP=LAP=LVEDP PAWP: Pulmon

Recent studies show the no prescription cialis value of performing an oral glucose tolerance test in all patients. Parents in primary care agreed that all 10 statements were important. To report the relationship between different optical ocular components and the influence of axial length on emmetropization.. IND (2.7 microM) decreased the contractions to both compounds and this was reversed with 2.8-7 nM PGE1. In 33 of 48 volunteers, two doses of vaccine induced antibodies that neutralized the homologous strain HIV-1/MN. Many aspects of the quiescence program as well as the mechanisms governing the entry and exit from quiescence remain poorly side effects for cialis understood. The purified protein has very low levels of RNase contamination and functioned normally in a variety of activity assays. The survey included 13 validated questions (eight on constipation and purchasing cialis on the internet five on incontinence) and was used to exclude subjects with pathological constipation or ...

The spin Hall effect is a spinCorbit coupling phenomenon, which enables electrical generation and recognition of spin currents. produced in a path perpendicular for an used charge current, which is recognized as the immediate spin Hall impact (DSHE)12,13,14,15,16,17,18,19. The spinCorbit discussion causes the inverse procedure for the DSHE also, an activity that changes a spin current right into a charge current: the inverse SHE20,21,22,23,24,25,26,27,28,29,30,31,32. SN 38 supplier The SHEs enable electrical recognition and era of spin currents, offering new ideas of spintronic products: spin Hall products33, such as for example SHE transistors34, spin photodetectors35,36, spin thermoelectric converters37,38 and spin Hall magnetic recollections18. An integral challenge for the introduction of such spin Hall products is to accomplish efficient transformation between spin and charge currents. Nevertheless, to realize effective spin-charge conversion, its been thought Rabbit Polyclonal to TSC2 ...

Arterial Spin labeling (ASL) is a fully non-invasive MRI method capable to quantify cerebral perfusion. However, gray (GM) and white matter (WM) ASL perfusions are difficult to assess separately due to limited spatial resolution increasing the partial volume effects (PVE). In the present study, ASL PVE correction was implemented based on a regression algorithm in 22 healthy young men. PVE corrected perfusion of GM and WM were compared to previous studies. PVE-corrected GM perfusion was in agreement with literature values. In general, WM perfusion was higher despite the use of PVE correction.. ...

In our lab, we seek to clarify this by using a more direct approach to assess vascular function (the vasodilatory capacity of vessels) in AD. We applied BOLD fMRI under hypercapnia (5% CO2 breathing) challenge to measure cerebrovascular reactivity (CVR) in a group of AD and normal control (NC) subjects. Baseline CBF was determined using pseudo-continuous arterial spin labeling (PCASL) technique. Spatial patterns of CVR and CBF deficits were compared. We found that regions of CVR deficits were restricted to anterior regions of the brain. This spatial pattern is drastically different from the patterns of CBF deficit measured in the same groups, which showed predominantly temporoparietal regions. Thus, CVR may be a better marker of vascular dysfunction. In the future, we hope to further investigate vascular dysfunction systematically in AD so that we can achieve a better understanding of the disease process.. ...

Arterial spin labeling methods allow to determine quantitative tissue blood flow values noninvasively. Arterial blood is labelled by an inversion pulse and the distribution of this intrinsic tracer is measured using magnetic resonance imaging. Experiments using an extra corporal in-vitro porcine kidney in a MR compatible set-up were carried out to determine the accuracy of blood flow values calculated from arterial spin labeling measurements. In a study of 36 brain tumor patients, spin labeling was compared to non-quantitative contrast-enhanced dynamic susceptibility-weighted perfusion imaging. Relative blood flow values determined with both methods were in good agreement, the linear regression coefficient in the tumor region was R=0.83. Due to the variable individual perfusion state, quantitative blood flow values determined using spin labeling play a minor role in the assessment of tumor grade. Application of spin labeling to angiography of major arteries was investigated. Dynamic spin ...

Arterial spin labeling methods allow to determine quantitative tissue blood flow values noninvasively. Arterial blood is labelled by an inversion pulse and the distribution of this intrinsic tracer is measured using magnetic resonance imaging. Experiments using an extra corporal in-vitro porcine kidney in a MR compatible set-up were carried out to determine the accuracy of blood flow values calculated from arterial spin labeling measurements. In a study of 36 brain tumor patients, spin labeling was compared to non-quantitative contrast-enhanced dynamic susceptibility-weighted perfusion imaging. Relative blood flow values determined with both methods were in good agreement, the linear regression coefficient in the tumor region was R=0.83. Due to the variable individual perfusion state, quantitative blood flow values determined using spin labeling play a minor role in the assessment of tumor grade. Application of spin labeling to angiography of major arteries was investigated. Dynamic spin ...

TY - JOUR. T1 - Experimental test of the spin mixing interface conductivity concept. AU - Weiler, Mathias. AU - Althammer, Matthias. AU - Schreier, Michael. AU - Lotze, Johannes. AU - Pernpeintner, Matthias. AU - Meyer, Sibylle. AU - Huebl, Hans. AU - Gross, Rudolf. AU - Kamra, Akashdeep. AU - Xiao, Jiang. AU - Chen, Yan Ting. AU - Jiao, Hujun. AU - Bauer, Gerrit E.W.. AU - Goennenwein, Sebastian T.B.. PY - 2013/10/23. Y1 - 2013/10/23. N2 - We perform a quantitative, comparative study of the spin pumping, spin Seebeck, and spin Hall magnetoresistance effects, all detected via the inverse spin Hall effect in a series of over 20 yttrium  ⠀Širon garnet/Pt samples. Our experimental results fully support present, exclusively spin current-based, theoretical models using a single set of plausible parameters for spin mixing conductance, spin Hall angle, and spin diffusion length. Our findings establish the purely spintronic nature of the aforementioned effects and provide a quantitative ...

Internet-Draft QUIC Spin Bit October 2018 S: The Spin bit is set 0 or 1 depending on the stored spin value that is updated on packet reception as explained in Section 2.2. R: Two additional bits are reserved for experimentation in the short header. 2.2. Setting the Spin Bit on Outgoing Packets Each endpoint, client and server, maintains a spin value, 0 or 1, for each QUIC connection, and sets the spin bit in the short header to the currently stored value when a packet with a short header is sent out. The spin value is initialized to 0 at each endpoint, client and server, at connection start. Each endpoint also remembers the highest packet number seen from its peer on the connection. The spin value is then determined at each endpoint within a single connection as follows: o When the server receives a packet from the client, if that packet has a short header and if it increments the highest packet number seen by the server from the client, the server sets the spin value to the value observed in ...

3D arterial spin labeling (3D ASL) and CT perfusion (CTP) can evaluate the changes of cerebral blood flow(CBF) after carotid endarterectomy(CEA). The aim of this study is to evaluate the changes of CBF after CEA using 3D ASL and CTP respectively, and to compare the consistency of the two methods. Compared with CTP, changes of CBF values obtained by ASL were similar. ASL has similar evaluation results with CTP. As ASL is a noninvasive imaging tool, it has potential to quantitative evaluate hemodynamic changes after CEA. ...

Accurate measurement of CBF in advanced cerebrovascular disease is difficult. PET remains the criterion standard, and current MR imaging vendor implementations of arterial spin-labeling have yet to be proved/validated for clinical use.28 The use of BOLD as a surrogate measure of CBF is common and has been shown to correlate well with other modalities, including FAIR arterial spin-labeling29 (also see Duffin et al9 and Tancredi et al30 for discussions). Nevertheless, the relationship between blood flow and BOLD is nonlinear.31,32 The atlas approach helps to mitigate this issue. In this article, the z scores account for the limitations of BOLD reflecting CBF because this measure of CBF was used in both the patient studies and the atlas. As improved methods of measuring CBF become available, the same analysis methodology can also be applied.. Within-subject variability of CVR may differ more with age and sex than in the men in our reference cohort.33 In this study, we examined male subjects and ...

Arterial Spin Labeling (ASL) is an increasingly popular tool to study the brain. What sets it apart from other neuroimaging methods is the combination of quantitative measurements of a physiologically well-defined process, namely perfusion, and a completely non-invasive acquisition methodology. Cerebral perfusion is a critical component to brain health, as it is the primary means to deliver nutrients to support brain function as well as clearing waste products.

Arterial Spin Labeling (ASL) is an increasingly popular tool to study the brain. What sets it apart from other neuroimaging methods is the combination of quantitative measurements of a physiologically well-defined process, namely perfusion, and a completely non-invasive acquisition methodology. Cerebral perfusion is a critical component to brain health, as it is the primary means to deliver nutrients to support brain function as well as clearing waste products.

Kai-Hsiang Chuang, F. Kober, Min-Chi Ku. Quantitative Analysis of Renal Perfusion by Arterial Spin Labeling. Preclinical MRI of the kidney, pp.655-666, 2021, ⟨10.1007/978-1-0716-0978-1_39⟩. ⟨hal-03122960⟩ ...

DUGi: Viewing Item from repository DUGiDocs: The decomposition of 〈͈Ŝ²〉 into atomic and diatomic contributions (local spin analysis) is used to detect and quantify the polyradical character of molecular systems. A model triradical system is studied in detail, and the local spin analysis is used to distinguish several patterns of local spin distributions and spin-spin interactions that can be found for different electronic states. How close a real molecular system is to an ideal system of k perfectly localized spin centers is utilized to define a measure of its k-radical character. The spin properties and triradical character of the lowest-lying electronic states of a number of all σ, all π, and σ-π organic triradicals are discussed in detail. The local spin contributions exhibit good correlation with experimental triradical stabilization energies

Summarizing the process, Boehme says, We basically wrote 1 in atoms nuclei. We have shown we can write and read [spin data in nuclei], and shown that the information can be repeatedly read from the nuclei for an average of 112 seconds before all the phosphorus nuclei lose their spin information. In a much shorter time, the physicists read and reread the same nuclear spin data 2,000 times, showing the act of reading the spin data doesnt destroy it, making the memory reliable, Boehme says. Reading out the data stored as spin involved reading the collective spins of a large number of nuclei and electrons, Boehme says. That will work for classical computers, but not for quantum computers, for which readouts must be able to discern the spins of single nuclei, he adds. Boehme hopes that can be achieved within a few years ...

where σxi is the Pauli matrix acting on the ith spin along the x direction, Jij the Ising coupling between spins i and j, and Bz the transverse magnetic field. The spin-spin interaction is long range and falls off approximately as a power law Jij~J0/,i-j,α . We studied the response of the system as a function of the ratio of the two competing energy scales in the Hamiltonian, namely J0 and B. The experiment we had in mind was very simple: prepare the spins along the x-axis, quench the Hamiltonian and then measure the magnetization of the spins along the x-basis over long times. The question we wanted to answer was: is there a dynamical phase transition, namely a non-analytic change in the properties of the system, as we vary the ratio B/ J0?. Ideally, to answer this question and observe a non-analytic response of the system, we should have taken the thermodynamic limit both numerically and experimentally. Numerically this is possible for those few cases where the system can be solved ...

The electron paramagnetic resonance signal of the cupric ion (its perpendicular component) at −196°C was found to be different in shape in human blood plasma and serum. On the addition of acid, substrate of ceruloplasmin, reducing agent, or denaturing agent, serum exhibited a complex electron paramagnetic resonance spectrum similar to that of a copper-diethyldithiocarbamate complex in an organic solvent, with a simultaneous disappearance of the cupric ion signal. Such an electron paramagnetic resonance spectrum occurred only from human serum but not from animal (guinea pig, mouse, rat, cattle, or monkey) serum.. PDF Article ...

TY - JOUR. T1 - Electron paramagnetic resonance spectrum of radical pairs in ultraviolet irradiated (Nh4)2s208 single crystals. AU - Liu, Kuo Tung. AU - Yu, Jiang Tsu. N1 - Funding Information: The authors gratefully thank the National Science Council of the Republic of China for the support given during the period of this investigation.. PY - 1994/9. Y1 - 1994/9. N2 - Irradiation of (NH4)2S208 single crystals with ultraviolet (UV) light produces two kinds of radical pair, I and II. Radical pair I is stable at room temperature, and can be produced via UV irradiation at room temperature. The electron paramagnetic resonance (EPR) spectrum exhibited by radical pair I is similar to that of SOJ pairs in UV irradiated K2S208 crystals observed previously, and can be identified similarly. Radical pair II can be produced by UV irradiation and detected by EPR only at low temperatures. Radical pair II, which could be identified as SOJ pairs, exhibits a limited lifetime at room temperature. A rigorous ...

This chapter presents the background, nomenclature, and theory of ESR spectroscopy. domains in ESR parameter space. PDF. ESR-1 Experiment #2B: Electron Spin Resonance Spectroscopy I. John E. Wertz, James R. Bolton. Electron Spin Resonance Spectroscopy Electron Spin Resonance (ESR) spectroscopy, also referred to as Electron Paramagnetic Resonance (EPR) spectroscopy, is a versatile, nondestructive analytical technique based on the absorption of microwave radiation in presence of an applied field by paramagnetic species. Request PDF , Principles and Applications of ESR Spectroscopy , The ESR (electron spin resonance) method is employed for studies of paramagnetic substances … Pages 1-20. Electron spin resonance spectroscopy (ESR) or electron paramagnetic resonance (EPR) is a technique for studying chemical species that have one or more unpaired electrons, such as organic and inorganic free radicals or inorganic complexes possessing a transition metal ion. Introduction Electron spin resonance ...

Read An Electron Paramagnetic Resonance Method for Measuring the Affinity of a Spin-Labeled Analog of Cholesterol for Phospholipids, The Journal of Membrane Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

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Rainer Grün. This will be achieved by looking for the spin … Electron spin resonance (ESR) is a spectroscopic technique that detects the transitions induced by electromagnetic radiation between the energy levels of electron spins in the presence of a static magnetic field. Uhlenbeck, in 1925, recommended that an electron has an inherent angular momentum that is a magnetic moment that is recognized as spin.In atomic physics, the inherent angular momentum of a particular particle is parametrized by spin quantum number. ESR only works with unpaired electrons, though, not the usual paired electrons of molecules. Energy-level Diagram For Two Spin States as a Function of Applied Field B. For electron spin resonance (ESR) studies, we obtained solvent-extractable free radicals from 1,3-butadiene soot from brief liquid-solid extractions with ultra-pure toluene, DMSO:water (4:1, v/v), n-hexane, and 3% aqueous sodium dodecyl sulfate. electron spin resonance synonyms, electron spin resonance ...

Electron Spin Resonance David J. Lurie, PhD Bio-Medical Physics, School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK 1. 13/02/2020 14/04/2020 Chemistry ABC 0 Comments electron spin resonance, esr, resonance, spectroscopy After Very Hardworking by contacting Toppers of Gate we have got E S R Spectroscopy Handwritten Notes Pdf. • Net spin S = 0 • Some chemical species have UNPAIRED electrons • Atoms H, Na, transition metals • Recall Stern-Gerlach experiment (s = ±±±± ½) • Molecules: O 2, NO Proportionality Factor Atherton, N. M. Principles of Electron Spin Resonance; Ellis Horwood: Chichester, 1993. how is, Nuclear Magnetic Resonance - . nuclear magnetic resonance (nmr), ATOMIC SPECROSCOPY (AS) - . PPT - Electron Spin Resonance Spectroscopy PowerPoint presentation , free to download - id: 3c9577-Y2VkZ, The Adobe Flash plugin is needed to view this content. The PowerPoint PPT presentation: Electron Paramagnetic Resonance (EPR) is the property of ...

TY - JOUR. T1 - Kinetic and stoichiometric assessment of the antioxidant activity of flavonoids by electron spin resonance spectroscopy. AU - McPhail, D B AU - Hartley, R C AU - Gardner, P T AU - Duthie, G G. PY - 2003/3/12. Y1 - 2003/3/12. N2 - dThere is current interest in the use of naturally occurring flavonoids as antioxidants for the preservation of foods and the prevention of diseases such as atherosclerosis and cancers. To establish the molecular characteristics required for maximum antioxidant activity, electron spin resonance (ESR) spectroscopy has been used to determine the stoichiometry and kinetics of the hydrogen-donating ability of 15 flavonoids and D-alpha-tocopherol to galvinoxyl, a resonance-stabilized, sterically protected aryloxyl radical. The second-order reaction rates, which will be governed by O-H bond dissociation energies, were myricetin , morin , quercetin , fisetin similar to catechin , kaempferol similar to luteolin , rutin , D-alpha-tocopherol , taxifolin , ...

ELECTRON SPIN RESONANCE OBJECTIVES * To learn some properties of a simple microwave reflection spectrometer. Here, we report a cavity-less technique which makes use of only an impedance analyzer and a copper strip coil to detect L-band EPR ( f = 1-3 GHz) in the standard EPR marker 2,2-diphenyl … The radical scavenging effects of chitooligosaccharides (COSs) on hydroxyl radical, superoxide radical, alkyl radical, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical were investigated using a spin-trapping electron spin resonance (ESR) method and compared with the ESR signal intensity. ×zÆE^{¯êb¸]Á&] ðBÁ÷¢VQ^ ¥¢¦; WF0 ác³ Electron spin resonance (ESR) is a useful tool for investigating the energy absorption spectra of many materials with unpaired electrons (paramagnetic materials). 2. A ball with a central rod magnet, which rotates with low fric- tion on an air cushion, acts as model electron. Determination of antioxidant capacity of diverse fruits by electron spin resonance (ESR) and ...

We have recently achieved electron spin resonance (ESR) of single alkali-metal atoms isolated on helium (He) nanodroplets. A two-laser pump/probe setup for optically detected magnetic resonance is applied, which is based on magnetic circular dichroism to selectively address spin states. The influence of the helium droplet on the alkali-metal valence-electron wave function is directly noticeable as a shift of the ESR transitions with respect to that of free atoms. This perturbation depends on the size of the droplets and can be modeled with an increase of the hyperfine constant, that is an increase of the Fermi contact interaction. After careful characterization of the Rb--He-droplet system the method is being developed into a more universal diagnostic tool to study spin dynamics. ESR silent species located inside the droplet can be investigated by utilizing the surface Rb atom as spin label, and the droplet size is a convenient handle to control the distance between the two. In case of species ...

TY - JOUR. T1 - Noise reduction in 3D perfusion imaging by attenuating the static signal in arterial spin tagging (ASSIST). AU - Ye, Frank Q.. AU - Frank, Joseph A.. AU - Weinberger, Daniel R.. AU - McLaughlin, Alan C.. N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.. PY - 2000. Y1 - 2000. N2 - Phase-encoded multishot SPIRAL approaches were used to acquire true 3D cerebral blood flow images of the human head using arterial spin tagging approaches. Multiple-inversion background suppression techniques, which suppress phase noise due to interacquisition fluctuations in the static magnetic field, reduced the temporal standard deviation of true 3D ΔM images acquired using arterial spin tagging approaches by ~50%. Background suppressed arterial spin tagging (ASSIST) approaches were used to obtain high-resolution isotropic true 3D cerebral blood flow images, and to obtain true 3D activation images during cognitive (working memory) tasks.. AB - Phase-encoded multishot SPIRAL ...

TY - JOUR. T1 - A study of spin-lattice relaxation rates of glucose, fructose, sucrose and cherries using high-T c SQUID-based NMR in ultralow magnetic fields. AU - Liao, Shu-Hsien. AU - Wu, Pei Che. PY - 2017/7/5. Y1 - 2017/7/5. N2 - We study the concentration dependence of spin-lattice relaxation rates, T 1 -1, of glucose, fructose, sucrose and cherries by using high-T c SQUID-based NMR at magnetic fields of ∼97 μT. The detected NMR signal, Sy (T Bp), is fitted to [1 - exp(-T Bp/T 1)] to derive T 1 -1, where Sy (T Bp) is the strength of the NMR signal, T Bp is the duration of pre-polarization and T 1 -1 is the spin-lattice relaxation rate. It was found that T 1 -1 increases as the sugar concentrations increase. The increased T 1 -1 is due to the presence of more molecules in the surroundings, which increases the spin-lattice interaction and in turn enhances T 1 -1. The T 1 -1versus degrees Brix curve provides a basis for determining unknown Brix values for cherries as well as other ...

Resulting energy levels of an electron in a magnetic field Ebsworth, E. A. V.; Rankin, David W. H.; Cradock, Stephen Structural Methods in Inorganic Chemistry; CRC Press: Boca Raton, 1987. infrared. Winner of the Standing Ovation Award for Best PowerPoint Templates from Presentations Magazine. To Provide A Classical Analog PPT. - ... spinning protons act like bar magnets. A surprisingly large number of materials have unpaired electrons. The electron spin resonance spectrum of a free radical or coordination complex with one unpaired electron is the simplest of all forms of spectroscopy. - Electron Spin Resonance (ESR) Spectroscopy applied to species having one or more unpaired electrons : free radicals, biradicals, other triplet states, transition ... Nuclear Magnetic Resonance (NMR) Spectroscopy. ESR is an acronym for Electron Spin Resonance. EPR (Electron Paramagnetic Resonance) is a spectroscopic technique that detects species that have unpaired electrons. optical microscopy -, ...

However, electron spins have yet to be used in realistic electronic devices except as part of magnetic devices for information storage. The reason is that spin polarization in a semiconductor is easily randomized, and consequently, it is difficult to transport spin polarization over a long distance.. An electron spin itself is a quantum spin angular momentum. Electrical transport and the manipulation of spin polarization are essential technologies if electron spins are to be employed in a device.. However, in actual materials, electron spins are randomized by the multiple scattering of electrons, resulting in spin depolarization in finite time. This phenomenon is called spin relaxation, and it results in spin polarization having a short transport length in a device. To realize spin functional devices, it is important to suppress spin relaxation and achieve more stable manipulation of electron spins.. The research team has demonstrated long-distance spin transport by electrical means in a ...

The concentration-dependent binding of four nitroxide spin-labeled derivatives of phenytoin (Compound I) to bovine serum albumin and human sera has been investigated. The spin label moiety was attached to phenytoin either at position 3-N via a carbimidomethyl linkage (Compound II) or at a 4-phenyl position via an amide linkage (Compounds III-V). Two of the phenyl labels (Compounds III and IV) differed only in the presence of a double bond in the pyrroline ring in Compound IV, and Compound V had the amide linkage reversed as compared with Compound III. The results of the binding studies were compared with those obtained by equilibrium dialysis of [14C]phenytoin. The spin labels were found to bind less strongly than [14C]phenytoin, with the order of binding of the spin-labeled phenytoins being IV , III , II , V. Studies with salicylic acid and phenylbutazone, known competitors of phenytoin binding, showed that the competition of spin label II paralleled that of [14C]phenytoin more than did the ...

Since electron spin resonance is an excellent analytical method for paramagnetic species and free radicals, it can be used to obtain a variety of kinetic and thermodynamic data. To provide a classical analog to spin resonance mental model, a spinning ball with a central magnet is required. Structure Determination: Nuclear Magnetic Resonance Spectroscopy. 1. concepts. brief discussion of principle, instrumentation and applications optical microscopy -, Ultraviolet-Visible Spectroscopy - . The two states are labeled by the projection of the electron spin, m s, on the direction of the magnetic field. A surprisingly large number of materials have unpaired electrons. EPR = ESR E Electron -study of unpaired electron spins, and their interaction with their environment. nonzero. what is the source and how is it working? To view this presentation, youll need to allow Flash. And theyre ready for you to use in your PowerPoint presentations the moment you need them. Electron Spin Resonance, ESR, is a ...

BACKGROUND AND PURPOSE: Current knowledge of the collateral circulation remains sparse, and a noninvasive method to better characterize the role of collaterals is desirable. The aim of our study was to investigate the presence and distal flow of collaterals by using a new MR perfusion territory imaging, vessel-encoded arterial spin-labeling (VE-ASL). MATERIALS AND METHODS: Fifty-six patients with internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis were identified by sonography, VE-ASL was performed to assess the presence and function of collateral flow. The perfusion information was combined with VE maps into high signal-intensity-to-noise-ratio 3-colored maps of the left carotid, right carotid, and posterior circulation territories. The presence of the anterior and posterior collateral flow was demonstrated by the color of the standard anterior cerebral artery/MCA flow territory. The distal function of collateral flow was categorized as adequate (cerebral blood flow [CBF] >= ...

Applications of NMR spectroscopy. Structure of organic and inorganic free radicals can be identified. Applications Electron spin resonance (ESR) spectroscopy is also known as Electron paramagnetic resonance (EPR) It is absorption spectroscopy similar to NMR, possible only with molecules having unpaired electrons Instead of Radiowaves in NMR, Microwaves is used in ESR 2. Structural elucidation: Most organic compounds have hydrogen in them. A broad-spectrum review of the applications of electron spin resonance to advanced materials is presented. Thus it helps to understand the structure of a compound. 2 Electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials with unpaired electrons.The basic concepts of EPR are analogous to those of nuclear magnetic resonance (NMR), but it is electron spins that are excited instead of the spins of atomic nuclei.EPR spectroscopy is particularly useful for studying metal complexes or organic radicals. ...

This report summarizes recent investigations that relate physical changes in macromolecular protein structures to biological functions. It is based on a review by scientists studying protein structure changes induced by van der Waals forces model cell membrane systems that measure the functions of the enzyme permeases the biological applications of nuclear magnetic resonance and electron spin resonance spectra and spin-labeling techniques fluorescence spectra, polarization and decay times, and absorption spectroscopy as indicators of biological events and the significance of molecular geometric changes in a series of biologically active compounds as related to their chemical structure. The topics include the nature of changes produced by chemicals at cell surfaces, enzyme-substrate interactions, novel concepts of charge transport through biological substrates, and their relationship to fine-structure changes in living systems. Author

With more than 940,000 new colorectal cancer cases worldwide each year, there is no better way for colorectal cancer routine screening. The aim of this study was to investigate whether the fatty acid binding to albumin is detectably and significantly altered in colorectal cancer patients when compared with healthy people, in order to find a better way for colorectal cancer diagnosis. One hundred and forty-one patients operatively treated for colorectal cancer were included in the examination, and 180 healthy people were also enrolled as controls. Commercial 16-doxyl stearic acid was used as spin probe. Serum albumin was analyzed by electron paramagnetic resonance (EPR) with spin probe. Discriminant analysis was carried out using the measured EPR spectra by SPSS 20.0. Of the original grouped cases, 89.4% were correctly classified. Of the

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. principles and applications of esr spectroscopy Oct 29, 2020 Posted By Yasuo Uchida Media Publishing TEXT ID e476e21e Online PDF Ebook Epub Library molecular physics physical chemistry biochemistry or spectroscopy the This method and the related NMR or nuclear magnetic resonance Principles and Applications of ESR Spectroscopy fills the gap between the detailed monographs in ESR spectroscopy and the general textbooks in molecular physics, physical chemistry, biochemistry or spectroscopy. Electron spin resonance spectroscopy (ESR) or electron paramagnetic resonance (EPR) is a technique for studying chemical species that have one or more unpaired electrons, such as organic and inorganic free radicals or inorganic complexes possessing a transition metal ion. The ESR (electron spin resonance) method is employed for studies of paramagnetic substances most commonly in liquids and solids. ...

0031]Thus, in the method of the invention, applying an amplitude modulated form of the labeling RF irradiation for the control was evaluated. In particular, it was observed that when a constant RF irradiation at a fixed frequency, f0, is multiplied by a sine wave at frequency f1, the signal produced is mathematically identical to continuous irradiation at two different frequencies, f0+f1 and f0-f1. If applied in the presence of a magnetic field gradient, each would separately perturb, such as by adiabatic inversion, inflowing arterial spins. When performed simultaneously, the combined effect is complicated because the equations governing spin evolution are not linear in the applied RF. However, the nature of resonance suggests that the effect of the first inversion on spins located near the second inversion plane should be small as long as the frequency spacing between the planes is large. In this case, the spins will be inverted twice after flowing through the two inversion planes, as ...

en] The C-phenyl-N-tert-butylnitrone/azobisisobutyronitrile pair is able to impart control to the radical polymerization of n-butyl acrylate as long as a two-step process is implemented, that is, the prereaction of the nitrone and the initiator in toluene at 85 degrees C for 4 h followed by the addition and polymerization of n-butyl acrylate at 110 degrees C. The structure of the in situ formed nitroxide has been established from kinetic and electron spin resonance data. The key parameters (the dissociation rate constant, combination rate constant, and equilibrium constant) that govern the process have been evaluated. The equilibrium constant between the dormant and active species is close to 1.6 x 10(-12) mol L-1 at 110 degrees C. The dissociation rate constant and the activation energy for the C-ON bond homolysis are 1.9 x 10(-3) s(-1) and 122 +/- 15 kJ mol(-1), respectively. The rate constant of recombination between the propagating adical and the nitroxide is as high as 1.2 x 10(9) L mol(-1) ...

TY - JOUR. T1 - Arterial spin labeling perfusion of the brain. T2 - Emerging clinical applications. AU - Haller, Sven. AU - Zaharchuk, Greg. AU - Thomas, David L.. AU - Lovblad, Karl Olof. AU - Barkhof, Frederik. AU - Golay, Xavier. N1 - Publisher Copyright: © RSNA, 2016. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 2016. Y1 - 2016. N2 - Arterial spin labeling (ASL) is a magnetic resonance (MR) imaging technique used to assess cerebral blood flow noninvasively by magnetically labeling inflowing blood. In this article, the main labeling techniques, notably pulsed and pseudocontinuous ASL, as well as emerging clinical applications will be reviewed. In dementia, the pattern of hypoperfusion on ASL images closely matches the established patterns of hypometabolism on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) images due to the close coupling of perfusion and metabolism in the brain. This suggests that ASL might be considered as an alternative for ...

The existence of a mucilaginous envelope, sheath or capsule is usual in many desmids, but few data concerning its function are available. Previous studies of the transport function and permeation of molecules through the algae capsules were done using the algae Spondylosium panduriforme and Nephrocytium lunatum, the Electron Paramagnetic Resonance (EPR) technique, and different spin labels. The results suggested that the capsule functions as a selective diffusion medium. In the present work charged and uncharged molecules (spin labels group A) and Staurastrum iversenii var. americanum (Desmids),whose alga presents a great mucilaginous capsule, were used. Charged nitroxide molecules similar to amino acids (spin labels group B) were also used allowing a better understanding of the electrostatic effect in the permeation process across the capsule. The role of the cell capsule in the solute diffusion was evaluated by determining the capsulated and decapsulated cell permeation times. The permeation ...

The Robinson group specializes in using a variety of Electron Paramagnetic Resonance (EPR) techniques, including continuous wave and pulsed Saturation Recovery (pSR) and pulsed Electron-Electron Double Resonance (pELDOR) EPR at 2 and 10 GHz. The research areas of interest include: dynamics of B-form duplex DNA and protein-DNA binding (as part of the process of DNA recognition); protein-RNA interactions; the interaction of interfacial signaling proteins and membranes; and the organization of organic chromophores in polymer matrices. The group collaborates with Larry Dalton, J. Michael Schurr, and Michael Gelb (all UW Chemistry) as well as Snorri Sigurdsson (University of Iceland), and Albert Beth and Eric Hustedt (Vanderbilt University).. The Robinson laboratory contains a CW/pulsed 10 GHz and a CW/pulsed 2 GHz EPR spectrometers. In addition, the Robinson group is responsible for the shared EPR instrumentation (from NIH-IEHS), which is used by more than a dozen groups around the UW campus. The ...

Site-directed spin labeling (SDSL) in combination with electron paramagnetic resonance (EPR) spectroscopy is a rapidly expanding powerful biophysical technique to study the structural and dynamic properties of membrane proteins in a native environment. Membrane proteins are responsible for performing important functions in a wide variety of complicated biological systems that are responsible for the survival of living organisms. In this review, a brief introduction of the most popular SDSL EPR techniques and illustrations of recent applications for studying pertinent structural and dynamic properties on membrane proteins will be discussed ...

Despite continuous scientific and technological advances in MR imaging, MR perfusion methods have not yet been widely deployed for routine clinical diagnostics. This is especially true for ASL (arterial spin labelling) methods used to evaluate cerebral perfusion. This method does not require a contrast agent, as new discoveries about gadolinium accumulation in the cerebellum and brain nucleus appear to be a valuable asset and provide the opportunity to be more widely deployed in clinical practice. The aim of this paper is to present the historical determinants of the development of MR perfusion techniques, the disadvantages and advantages and possible clinical applications and prospects of ASL development. Both historical articles published on MR in the 1990s and current research between 2006-2016 have been reviewed. The authors present in the work the MR perfusion method focusing on issues related to arterial spin labeling (ASL). Historically CASL (continuous ASL) and PCSL (pulsed ASL) ...

Janis has standard designs available for electron spin resonance (ESR) spectroscopy, plus the capability of custom building any system to your specifications. Electron spin resonance (ESR) spectroscopy has been used for over 50 years to study a variety of paramagnetic species. Finally, the potential use of ESR technique in investigating microstructure change, phase transition and viscosity related properties during food formulation, processing, and storage was briefly mentioned, along with its potential in determination of radio‐stability of food components. Applications of ESR spectra: • It decides the site of unpaired electrons. Fax: +1(301)‐314‐3313. (Also known as EPR, Electron Paramagnetic Resonance) ESR is a method for observing the behavior (dynamics) of the electrons within a suitable molecule, and for analyzing various phenomena by identifying the electron environment. Wide Field of Applications. Systems Biology of Free Radicals and Antioxidants. Principles and Applications of ...

BACKGROUND AND PURPOSE:Cerebral perfusion assessment is important in the preoperative evaluation and postoperative follow-up of patients with Moyamoya disease. The objective of this study was to evaluate the correlation of quantitative CBF measurements performed with arterial spin-labeling-MR imaging and H2[(15)O]-PET in children and young adults with Moyamoya disease.MATERIALS AND METHODS:Thirteen children and young adults (8 female patients; age, 9.7 ± 7.1 years; range, 1-23 years) with Moyamoya disease underwent cerebral perfusion imaging with H2[(15)O]-PET (Discovery STE PET/CT, 3D Fourier rebinning filtered back-projection, 128 × 128 × 47 matrix, 2.34 × 2.34 × 3.27 mm(3) voxel spacing) and arterial spin-labeling (3T scanner, 3D pulsed continuous arterial spin-labeling sequence, 32 axial sections, TR = 5.5 seconds, TE = 25 ms, FOV = 24 cm, 128 × 128 matrix, 1.875 × 1.875 × 5 mm(3) voxel spacing) within less than 2 weeks of each other. Perfusion of left and right anterior cerebral ...

The magnetic and electronic properties of heavily doped n-type 6H SiC samples with a nitrogen concentration of 10{sup 19} and 4 × 10{sup 19 }cm{sup −3} were studied with electron spin resonance (ESR) at 5-150 K. The observed ESR line with a Dysonian lineshape was attributed to the conduction electrons (CE). The CE ESR (CESR) line was fitted by Lorentzian (insulating phase) (T , 40 K) and by Dysonian lineshape (metallic phase) above 40 K, demonstrating that Mott insulator-metal (IM) transition takes place at ∼40 K, accompanied by significant change in the microwave conductivity. The temperature dependence of CESR linewidth follows the linear Korringa law below 40 K, caused by the coupling of the localized electrons (LE) and CE, and is described by the exponential law above 40 K related to the direct relaxation of the LE magnetic moments via excited levels driven by the exchange interaction of LE with CE. The g-factor of the CESR line (g{sub ‖} = 2.0047(3), g{sub ⊥} = 2.0034(3)) is ...

The present work comparatively analyzes the interaction of alpha-MSH and its more potent and long-acting analog [Nle(4), D-Phe(7)]alpha-MSH (NDP-MSH) with lipid bilayers. the peptides were spin labeled with Toac (2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid) at the N-terminal, as those derivatives had been previously shown to keep their full biological activity. Due to the special rigidity of the Toac covalent binding to the peptide molecule, this spin label is highly sensitive to the peptide backbone conformation and dynamics. the peptides were investigated both by the electron spin resonance (ESR) of Toac(0) and the time resolved fluorescence of Trp(9) present in the peptides. the Toac(0) ESR of the membrane-bound peptides indicates that the two peptides are inserted into the bilayer, close to the bilayer surface, in rather similar environments. A residue titration around pK(a) 7.5, possibly that of His(6), can be clearly monitored by peptide-lipid partition. Trp(9) time ...

ESR Spectroscopy (Electron Spin Resonance Spectroscopy or Electron Paramagnetic Resonance Spectroscopy) is a technique used for studying chemical species that

In a newly published study, university researchers propose a new way to probe Earths deep interior that relies on a fifth force of nature called a long-range spin-spin interaction.. Researchers from Amherst College and The University of Texas at Austin have described a new technique that might one day reveal in higher detail than ever before the composition and characteristics of the deep Earth.. Theres just one catch: The technique relies on a fifth force of nature (in addition to gravity, the weak and strong nuclear forces and electromagnetism) that has not yet been detected, but which some particle physicists think might exist. Physicists call this type of force a long-range spin-spin interaction. If it does exist, this exotic new force would connect matter at Earths surface with matter hundreds or even thousands of kilometers below, deep in Earths mantle. In other words, the building blocks of atoms-electrons, protons, and neutrons-separated over vast distances would feel each others ...

Department of Medical and Biological Physics, N. I. Pirogov 2nd Moscow Medical Institute. Translated from Meditsinskaya Tekhnika, No. 6, pp. 17-18, November-December, 1991. ...

Get this from a library! Electron Paramagnetic Resonance of d Transition Metal Compounds.. [F E Mabbs; D Collison] -- Electron paramagnetic resonance (epr) spectroscopy is a sensitive and versatile method of studying paramagnets, which is finding increasing use in chemistry, biochemistry, earth and materials ...

Arterial Spin Labeling (ASL) enables measuring cerebral blood flow in MRI without injection of a contrast agent. Perfusion measured by ASL carries relevant information for patients suffering from pathologies associated with singular perfusion patterns. However, to date, individual identification of abnormal perfusion patterns in ASL usually relies on visual inspection or manual delineation of regions of interest. In this paper, we introduce a new framework to automatically outline patterns of abnormal perfusion in individual patients by means of an ASL template. We compare two models of normal perfusion and assess the quality of detections comparing an a contrario approach to the Generalized Linear Model (GLM).

In the last few years, fast arbitrary waveform generates (AWGs) have become commercially available in the field of electron paramagnetic resonance (EPR). Pairing AWGs with local oscillator devices gives access to frequency and amplitude modulated microwave pulses and sufficiently broadband digitizers exist for appropriate detection. But replacing monochromatic rectangular pulses with frequency and amplitude modulated pulses is not an innocent procedure. Compared to the one during monochromatic rectangular pulse, spin dynamics during frequency-swept pulses is fundamentally different and as a consequence routine experiments can lead to surprising new results. Although passage pulses are well known and studied in nuclear magnetic resonance (NMR) spectroscopy, their effects are far from being fully understood in EPR spectroscopy. In response to the need of a way to simulate pulse EPR experiments with frequency swept-pulses, the open-source spin dynamics analysis (SPIDYAN) toolbox, which runs in ...

In-beam measurement of the hydrogen hyperfine splitting and prospects for antihydrogen spectroscopy Nature Communications, Published online: 12 June 2017; doi:10.1038/ncomms15749 Comparing the ground-state hyperfine structure of antihydrogen to that of hydrogen will provide insights into CPT symmetry in nature. Here the authors report the most precise in-beam measurement of this quantity for hydrogen to demonstrate…

Biochemistry. 2014 Feb 20. [Epub ahead of print]. Subtle Dynamics of holo Glutamine Binding Protein Revealed with a Rigid Paramagnetic Probe.. Liu Z, Gong Z, Guo DC, Zhang WP, Tang C.. Abstract. Bacterial periplasmic binding proteins (PBPs) are involved in the translocation of small molecules in the periplasm. To unload, the two domains of a PBP open up, allowing the ligand to exit. However, it is not clear whether there are dynamics near the binding site, which can facilitate the rapid dissociation of a ligand. To visualize such dynamics, we utilized paramagnetic relaxation enhancement (PRE) NMR, and introduced a rigid paramagnetic probe to a PBP, glutamine-binding protein (QBP) with its cognate ligand bound. A paramagnetic Cu(II) ion is sandwiched between an engineered di-histidine motif at a helix and an NTA capping molecule. The afforded paramagnetic probe is so rigid that PRE values calculated from a single structure of holo QBP largely agree with the observed values. The remaining PRE ...

Electron paramagnetic resonance (EPR) spectroscopy is an unambiguous method to measure free radicals. The use of selective spin probes...

Gravitational waves from binary black holes have the potential to yield information on both of the intrinsic parameters that characterize the compact objects: their masses and spins. While the component masses are usually resolvable, the component spins have proven difficult to measure. This limitation stems in great part from our choice to inquire about the spins of the most and least massive objects in each binary, a question that becomes ill defined when the masses are equal. In this Letter, we show that one can ask a different question of the data: what are the spins of the objects with the highest and lowest dimensionless spins in the binary? We show that this can significantly improve estimates of the individual spins, especially for binary systems with comparable masses. When applying this parametrization to the first 13 gravitational-wave events detected by the LIGO-Virgo Collaboration (LVC), we find that the highest-spinning object is constrained to have nonzero spin for most sources ...

Both the electron and the muon have spin ##1/2##, so their spin orientations must be specified. It is useful to take the axis that defines the spin quantization of each particle to be in the direction of its motion - each particle can then have its spin polarized parallel or antiparallel to this axis. In practice, electron and positron beams are often unpolarized, and muon detectors are normally blind to the muon polarization. Hence one should average the cross section over electron and positron spin orientations, and sum the cross section over muon spin orientations ...

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A Randomized, Multicenter, Open Label Study of MM-302 plus Trastuzumab vs. Chemotherapy of Physicians Choice plus Trastuzumab in Anthracycline Naive Patients with Locally Advanced/Metastatic HER2-Positive Breast ...