bluuebunny/crossref_metadata_2025_split huggingface dataset:
The calculation of frequency-dependent polarizabilities as pseudo-energy derivatives
Authors: Rice Julia E. , Handy Nicholas C. 
Published: July 2002

The definition of frequency-dependent polarizabilities α(−ω;ω), β(−2ω;ω,ω), β(−ω;ω,0), and β(0;ω,−ω) is discussed, and it is argued that the most convenient definitions are as energy derivatives, a pseudo-energy being defined as the expectation value of [H−i(∂/∂t)]. This definition outlines a straightforward procedure for obtaining frequency-dependent polarizabilities for all quantum chemistry methods including those which account for the effects of electron correlation. It is demonstrated at the self-consistent field level of theory that αλμ(−ω;ω) cos ωt may be considered as the derivative of the static dipole moment μλ with respect to the strength Eωμ of a frequency-dependent field Eωμ cos ωt (as is usual), or as the derivative of an appropriately defined frequency-dependent dipole moment μμ cos ωt with respect to a static field E0λ. In this way, polarizabilities may be determined from finite static field calculations on lower-order tensors. Therefore, α(−ω;ω) cos ωt is defined within second-order Mo/ller–Plesset perturbation theory (MP2) as the second derivative of the MP2 energy with respect to one static and one frequency-dependent field.
An analytic expression is given for αλμ(−ω;ω) at the MP2 level of theory. An MP2 frequency-dependent dipole expression is also defined, which if finite static field calculations are applied, gives the same values for αλμ(−ω;ω). MP2 values are reported for α(−ω;ω) of formaldehyde and ammonia for a range of frequency ω=0.01–0.1 a.u. From comparison of the self-consistent field (SCF) and MP2 values of the frequency-dependent contribution to ᾱ(−ω;ω), it is concluded that it is appropriate to use an SCF frequency-dependent correction in conjunction with a static polarizability determined at a higher level of theory in order to obtain an accurate value for ᾱ(−ω;ω) of H2CO in this frequency range. For ammonia, the frequency-dependent contribution to ᾱ(−ω;ω) is more sensitive to electron correlation. Nevertheless, compared to the total polarizability ᾱ(−ω;ω), the error in the frequency-dependent contribution determined using the SCF method is small (∼2% at ω=0.1 a.u.)
The Langevin/implicit-Euler/normal-mode scheme for molecular dynamics at large time steps
Authors: Zhang Guihua , Schlick Tamar 
Published: July 2002

As molecular dynamics simulations continue to provide important insights into biomolecular structure and function, a growing demand for increasing the time span of the simulations is emerging. Our focus here is developing a new algorithm, LIN (Langevin/implicit-Euler/normal mode), that combines normal-mode and implicit-integration techniques, for large time step biomolecular applications. In the normal-mode phase of LIN, we solve an approximate linearized Langevin formulation to resolve the rapidly varying components of the motion. In the implicit phase, we resolve the remaining components of the motion by numerical integration with the implicit-Euler scheme. Developments of the normal-mode phase of LIN are discussed in this paper. Specifically, we solve two crucial issues of the method. The first involves how to choose and how often to update the Hessian approximation for the linearized Langevin equation. This approximation must be computationally feasible and physically reasonable to capture the motion in the higher end of the vibrational spectrum. Three such general Hessian approximations are discussed. The related issue—the frequency of the Hessian update—is analyzed by projecting the motion onto the different vibrational modes. This analysis demonstrates that a one-picosecond interval is reasonable for updating the Hessian in the model system examined here.
In this connection, we illustrate that the high-frequency motions are highly localized while the low-frequency motions are delocalized. We also show rigorously that the mode amplitudes are inversely proportional to the frequency (consistent with the equipartition theorem), with 90% of the displacement fluctuations coming from a very small group of low-frequency modes. Anharmonic effects essentially influence the low-frequency modes. The second issue involves how to solve the linearized Langevin equation at large timesteps correctly, where the usual discretized formulation of the random force is invalid. This is accomplished by using analytic expressions for the distributions associated with positions and velocities of the individual oscillators as a function of frequency, obtained as the solution of the corresponding Fokker–Planck equation. We apply LIN with these developments to the nucleic acid component deoxycytidine with timesteps ranging from 100 to 1000 fs. We demonstrate that LIN is stable in these simulations, with energies fluctuating about the same values—and possessing overall similar dynamical features—in comparison to 1 fs explicit simulations, though the fluctuations are significantly larger at larger timesteps. Moreover, continuous dynamics is maintained, and pathway information can be obtained. Computational performance is competitive only at very large time steps: a gain factor of 3–4 is obtained for runs with 1000 fs time steps. Larger gains may be achieved for biomolecules, where sparsity and parallelization can be exploited significantly.
Stress and Social Support in Parents whose Children are Hepatitis B Virus (HBV) Carriers: A Comparison of Three Groups in Guangzhou
Authors: Lai Alice Cheng , Salili Farideh 
Published: July 2002

The present study compared the moderating effect of social support on parental stress variables and mental health among three groups of parents: parents of HBV (Hepatitis B Virus) children who attended the special health kindergarten, parents of HBV children who stayed at home, and parents of healthy children who attended the ordinary kindergarten. These families resided in the city of Guangzhou.A set of questionnaires measuring parental stress and social support were given to the mothers after a one‐hour interview. Results showed that parents of HBV children were significantly more stressed and psychologically at risk than parents of healthy children. They also sought help from social resources more often than the parents of healthy children. Parents of healthy children who attended the ordinary kindergarten reported the highest levels of overall social support, i.e. the number of very close friends and relatives with whom they could form close emotional attachments. Although they reported a lower number of acquaintances available, they also reported the most satisfactory relationships with the support provided by their acquaintances, lower levels of stress, fewer somatic problems, more adequate general health, and more perceived meaning in life than did parents of HBV children, and social support is one of the main influences on stress or parental health. The findings call for further research to focus on parents' well‐being and social support that is helpful in addressing the needs of the family.
A study of event‐related potential—P3 characteristics in children of alcoholics
Authors: SHARMA AVNEET , MALHOTRA SAVITA , RAGHUNATHAN MURUGESCHACHETTY , MALHOTRA ANIL 
Published: July 2002

AbstractAbstract Auditory P3 characteristics were studied in children (aged 8‐14 years) of male alcoholics without psychiatric problems and children of normal parents employing an oddball auditory paradigm. All the children of alcoholics were from families with multiple cases of alcoholism (each child had an average of 4.3 first‐ and second‐degree relatives including the father, meeting criteria for alcoholism). Subjects were presented with high and low pitched tones with global probabilities of 25% and 75% of total trials, respectively. The amplitude of P3 component was significantly reduced in high‐risk children (p < 0.001). Implications of the findings, including the role of P3 as biologi cal marker of risk for alcoholism, are discussed.
Alcoholic beverages and lipid peroxidation: relevance to cardiovascular disease
Authors: PUDDEY IAN B. , CROFT KEVIN 
Published: July 2002

AbstractOverall there is good evidence that alcohol consumption induces oxidative stress, and leads to lipid peroxidation, effects which have been linked to alcohol‐related toxicity and disease and may be relevant to alcoholatherosclerosis interrelationships. On the other hand, a protective effect of light to moderate alcohol consumption against cardiovascular disease is well recognized, with the further hypothesis that red wine offers extra cardiovascular protection due to its rich content of antioxidant phenolic compounds. Although this hypothesis is given some credence from in vitro data, controlled studies in humans have produced conflicting results. Clearly, the equally well described pro‐oxidant effects of alcohol and its metabolism have been insufficiently considered in the pursuit of what to many is an intuitively attractive hypothesis. Further studies are required to determine if red wine phenolics are actually absorbed from the gut and whether they offer any overall antioxidant protection in vivo. The hypothesis that red wine offers extra cardiovascular protection compared to other alcoholic beverages is not proven and must await the outcome of studies in which the full spectrum of the pro‐oxidant and antioxidant effects of alcoholic beverages are duly considered. In the absence of such studies, there are no grounds at present for the promotion of the consumption of alcoholic beverages on the basis of their putative “antioxidant” properties.
No allelic association of an exon 13 polymorphism of the Gsα gene to alcohol and/or drug dependence
Authors: KRANZLER HENRY R. , McCAUL MARY E. , GELERNTER JOEL , WAND GARY S. 
Published: July 2002

AbstractThe adenylyl cyclase signal transduction system, a ubiquitous second messenger system, has been identified as a potential marker for genetic risk of alcohol and drug dependence. Using the polymerase chain reaction (PCR) to amplify exon 13 of the Gsα gene, two alleles were distinguished by denaturing gradient gel electrophoresis. One allele, designed A, contained the previously published C in the codon for asparagine 371, while the second allele, designated A, contains a C‐T transition that conserves the asparagine residue at codon 371. The neutral polymorphism eliminates a Fok I restriction enzyme cleavage site, allowing use of restriction fragment length polymorphisms of PCR products to determine allelic frequency in 235 subjects with alcohol and/or drug dependence and in 85 control subjects. Since allele frequencies differ significantly by race, comparisons between affected individuals and controls were conducted separately for white and black groups. Within race, there were no significant differences in the frequency of the A allele among alcoholics, subjects dependent on cocaine or opioids, subjects dependent on these drugs and alcohol, and controls. We conclude that there is no association between alcohol and/or drug dependence and alleles of an exon 13 polymorphism of the Gsα gene in either black or white individuals.
The effect of acetaldehyde on human brain transketolase activity
Authors: ROOPRAI H. K. , PRATT O. E. 
Published: July 2002

AbstractChronic alcoholism and thiamine deficiency are well documented factors in the aetiology of Wernicke‐Korsakoff Syndrome. More recently, acetaldehyde (ACH) has been implicated as a possible aetiological factor. In the present investigation the direct effect of ACH was studied on the activity of transketolase, a thiaminedependent enzyme, as well as two non‐thiamine‐dependent enzymes (aspartate aminotransferase and lactate dehydrogenase), isolated from five control human brains. The concentration of ACH required to inhibit 50% activity of holo‐ and apo‐transketolase was 80 mM and 60 mM, respectively, whereas that for aspartate aminotransferase and lactate dehydrogenase was 14 mM and 10 mM, respectively. None of the enzymes were completely inhibited by the range of ACH concentrations used in the study. It was concluded that the thiamineindependent enzymes were markedly affected by the concentrations of ACH which did not affect the thiaminedependent enzyme, transketolase. In vitro studies with homogenates pre‐treated with ACH in the presence of various concentrations of glutathione showed that the latter had a protective effect against loss of transketolase activity.
How useful is aminolevulinic acid dehydratase as a marker of recent alcohol intake?
Authors: AUBIN HENRI‐JEAN , LAUREAUX CHANTAL , TILIKETE SAMIR , GILLET CLAUDINE , LEPETITCORPS ANNICK , NGUYEN THU , TROUPEL SOLANGE , PAILLE FRANCOIS , BARRUCAND DOMINIQUE 
Published: July 2002

AbstractAbstract Erythroycte delta aminolevulinic acid dehydratase (ALAD) has been suggested as a marker for detecting recent alcohol intake. Unlike other markers, ALAD activity decreases after alcohol intake. Review of the literature suggests that the main interest in this marker is because it increases rapidly after withdrawal. The present study investigated the changes in erythrocyte ALAD and serum gamma‐glutamyltransferase activities after alcohol withdrawal in 120 alcoholics. Our data showed that ALAD is less sensitive than GGT as an indicator of recent alcohol intake (56% and 84% abnormal, respectively). The increase in ALAD activity was greater between day 12 and 18 after withdrawal (11%) than between day 1 and 12 after withdrawal (5%). There were as many patients returning to normal values 12 and 18 days after withdrawal, for GGT as for ALAD. Thus, our results contradict the claim that ALAD rises rapidly after withdrawal. ALAD shows no advantage over GGT as a marker of recent alcohol intake.
Brain GABA metabolism after chronic ethanol consumption and withdrawal in rats
Authors: KANUNNIKOVA NINA P. , VINITSKAYA ANNA G. , DOROSHENKO YEVGENI M. , ZIMATKIN SERGEI M. 
Published: July 2002

AbstractAbstract We have studied the activities of the GABA metabolizing enzymes‐GABA aminotransferase (GABA‐AT), succinic semialdehyde dehydrogenase (SSA‐DH) and SSA reductase (SSA‐R) and the levels of GABA, glutamine and glutamate in rats preferring water (WP) or ethanol (EP) after 6 months of ethanol consumption and 12 hours to 7 days after withdrawal. We showed decreased GABA levels in the brain stem, decreased GABA‐AT activity in the hemispheres and brain stem, and enhanced GABA‐AT activity in the striatum of EP rats compared with the control or WP animals following chronic consumption of ethanol. We found decreased activity of SSA‐R and SSA‐DH in the hemispheres and brain stems of alcohol‐treated rats compared to the control rats. Withdrawal (0.5‐7 days) induced numerous profound changes in GABA metabolism.
Effect of oral yohimbine on withdrawal jumping behaviour of morphine‐dependent mice
Authors: Iglesias V. , Alamo C. , Cuenca E. , Morales L. , Perez‐Garcia C. , Alguacil L. F. 
Published: July 2002

AbstractAcute administration of the alpha‐2 adrenoceptor agonist clonidine and chronic administration of the alpha2 antagonist yohimbine both inhibit opioid withdrawal signs in experimental models of dependence and also in clinical studies with opiate abusers. There are exceptions to this general rule: restlessness or self‐reported abstinence in humans and withdrawal‐induced escape behaviour in rodents are resistant to inhibition by acute clonidine. We have explored the effect of the alpha‐2 antagonist yohimbine on morphine withdrawal‐induced escape behaviour in a mouse model that we have proposed to differentiate between the urge to escape (number of jumps) and non‐specific sedative/motor actions (height of jumps). Morphine dependence was induced by s.c. administration of a sustained‐release preparation (1 g/kg). Naloxone (1 mg/kg) was injected to precipitate withdrawal jumping 72 hours after morphine injection. Co‐treatment with yohimbine dissolved in the tap water (70 mg/l) decreased the number of jumps upon naloxone challenge, an effect which did not seem to be related with a sedative or toxic effect of the drug. This result confirms previous data and suggests that yohimbine could prevent the development of opioid dependence being active to decrease withdrawal‐induced escape behaviour. The mechanisms of this action are discussed.
Biochemical and genetic studies of Caucasian subjects with ethanol‐induced flushing reaction
Authors: Ward Roberta J. , Mccradden John , Tipton Keith , Sherwood Roy , Keating James , Peters Timothy J. , DE Witte Philippe 
Published: July 2002

AbstractThe prevalence of ethanol‐induced flushing was investigated in three different Caucasian student populations, namely Irish, Belgian and English. Approximately 45% of all female subjects reported a flushing reaction, while 33%, 17% and 9%, respectively, of male students reported this reaction. There was a high familial incidence of flushing in all groups, suggesting that a specific gene defect might be involved. Our previous investigations had inferred normal ALDH2 in such affected individuals, but low activities of erythrocyte ALDH1.1 Since the principal role of this cytosolic enzyme may be in the metabolism of biogenic amines, serotonin levels in platelet‐rich plasma and urinary adrenaline, noradrenaline and dopamine were assayed in affected individuals after an oral ethanol challenge. No consistent pattern was evident for any of these parameters in any of the subjects at the time intervals investigated. Genotyping for ADH31 and ADH32 showed a higher frequency for ADH31, 58%, than ADH32, 42%. This is comparable to the Caucasian controls and to our previously published data.
The reduction of large molecular profiles to informative
components using a Genetic Algorithm
Authors: Stefanini F. M. , Camussi A. 
Published: July 2002

Abstract
Motivation: Molecular profiles (DNA fingerprints) may be used to allocate an individual of unknown membership to one among the known groups of a reference population. Time and costs of profile assessment may be reduced by identifying informative profile components (markers).
Results: A genetic algorithm (GA) is proposed to identify promising candidate markers from a pilot experiment in which observations are supposed to be without measurement error. The analysis of simulated datasets suggests reasonable values for GA parameters and confirms that the GA finds components of the profile showing association with the considered groups. Our GA may be used to perform a first screening of candidate markers to be included in subsequent experiments.
Availability: The 32-bit executable (Windows 95, 98 and NT) is available at http://www.ds.unifi.it/~stefanin/bioinformatics.htm.
Contact: stefanin@ds.unifi.it
Supplementary Information: The algorithm is implemented for research purposes, i.e. a limited amount of input filtering and error messages are provided.
To whom correspondence should be addressed.
Evaluation of the Association Between Congenital Cytomegalovirus Infection and Pediatric Acute Lymphoblastic Leukemia
Authors: Geris Jennifer M. , Schleiss Mark R. , Hooten Anthony J. , Langer Erica , Hernandez-Alvarado Nelmary , Roesler Michelle A. , Sample Jeannette , Williams Lindsay A. , Dickens David S. , Mody Rajen J. , Ravindranath Yaddanapudi , Gowans Kate L. , Pridgeon Matthew G. , Spector Logan G. , Nelson Heather H. 
Published: January 2023

ImportanceAcute lymphoblastic leukemia (ALL) is the most common form of pediatric cancer, and a leading cause of death in children. Understanding the causes of pediatric ALL is necessary to enable early detection and prevention; congenital cytomegalovirus (cCMV) has recently been identified as a potential moderate-to-strong factor associated with risk for ALL.ObjectiveTo compare the prevalence of cCMV infection between ALL cases and matched controls.Design, Setting, and ParticipantsIn this population-based case-control study of ALL cases and matched controls, cases consisted of children aged 0 to 14 years between 1987 and 2014 with an ALL diagnosis identified through the Michigan Cancer Surveillance Program and born in Michigan on or after October 1, 1987. Cancer-free controls were identified by the Michigan BioTrust for Health and matched on age, sex, and mother’s race and ethnicity. Data were analyzed from November to May 2022.ExposurescCMV infection measured by quantitative polymerase chain reaction in newborn dried blood spots.Main Outcomes and MeasuresALL diagnosed in children aged 0 to 14 years.ResultsA total of 1189 ALL cases and 4756 matched controls were included in the study. Bloodspots were collected from participants at birth, and 3425 (57.6%) participants were male. cCMV was detected in 6 ALL cases (0.5%) and 21 controls (0.4%). There was no difference in the odds of cCMV infection comparing ALL cases with controls (odds ratio, 1.30; 95% CI, 0.52-3.24). Immunophenotype was available for 536 cases (45.1%) and cytogenetic data for 127 (27%). When stratified by subtype characteristics, hyperdiploid ALL (74 cases) was associated with 6.26 times greater odds of cCMV infection compared with unmatched controls (95% CI, 1.44-27.19).Conclusions and RelevanceIn this case-control study of cCMV and pediatric ALL, cCMV was associated with increased risk of hyperdiploid ALL. These findings encourage continued research.
Indigenous Peoples‐related environmental research within the basin of the Laurentian Great Lakes: A systematic map protocol
Authors: Serville‐Tertullien Marsha , Pirie Emma , Buell Mary‐Claire , Wall Barbara Moktthewenkwe , Furgal Chris 
Published: January 2023

Abstract

The North American Great Lakes Basin is the homeland for many First Nations, Métis and Native American Tribes. The terrestrial and aquatic ecological systems within this multinational region, which is of spiritual, cultural and subsistence significance to a diversity of Indigenous Peoples, are facing several natural and anthropogenic pressures. While there are many current and past research efforts and projects to address those pressures, the nature and range of environment‐related projects involving Indigenous Peoples or organizations remains unknown. This gap in knowledge presents a unique opportunity to identify and map past and current environmental and ecological research within the Great Lakes involving Indigenous Peoples.

A systematic search strategy will be applied to identify and capture peer‐reviewed publications that pertain to past and current environmental research within the Great Lakes basin that involve or are connected to Indigenous Peoples, following the procedures outlined in this systematic mapping protocol. Publications that pertain to environmental and ecological research with, for and by Indigenous Peoples within the Great Lakes, as determined by the use of suitable keywords, will be retrieved from four proposed online bibliographic platforms and databases. Searches will only include peer‐reviewed publications in the English language.

Final captures of the search results will be screened in two stages to identify potentially relevant papers. This will take place through (1) title and abstract screening and (2) full‐text analysis. Following the completion of the screening process, remaining papers will be coded and analysed through a narrative synthesis approach and descriptive statistics will be conducted. Environmental research captured through this systematic protocol will be geospatially mapped using the ArcGIS mapping software.

It is anticipated that the information obtained from the resulting systematic map will be beneficial for identifying gaps in environmental research to support and inform future initiatives for environmental research planning, policy and decision‐making with, for and by Indigenous Communities within the Great Lakes basin.