bluuebunny/crossref_metadata_2025_split huggingface dataset:
Latent variable modeling paradigms for genotype‐trait association studies
Authors: Liu Yan , Foulkes Andrea S. 
Published: September 2011

AbstractCharacterizing associations among multiple single‐nucleotide polymorphisms (SNPs) within and across genes, and measures of disease progression or disease status will potentially offer new insight into disease etiology and disease progression. However, this presents a significant analytic challenge due to the existence of multiple potentially informative genetic loci, as well as environmental and demographic factors, and the generally uncharacterized and complex relationships among them. Latent variable modeling approaches offer a natural framework for analysis of data arising from these population‐based genetic association investigations of complex diseases as they are well‐suited to uncover simultaneous effects of multiple markers. In this manuscript we describe application and performance of two such latent variable methods, namely structural equation models (SEMs) and mixed effects models (MEMs), and highlight their theoretical overlap. The relative advantages of each paradigm are investigated through simulation studies and, finally, an application to data arising from a study of anti‐retroviral‐associated dyslipidemia in HIV‐infected individuals is provided for illustration.
Guest‐Release Control in Enzyme‐Sensitive, Amphiphilic‐Dendrimer‐Based Nanoparticles through Photochemical Crosslinking
Authors: Raghupathi Krishna R. , Azagarsamy Malar A. , Thayumanavan S. 
Published: September 2011

AbstractStimuli sensitive, facially amphiphilic dendrimers have been synthesized and their enzyme‐responsive nature has been determined with dual fluorescence responses of both covalently conjugated and non‐covalently bound reporter units. These dual responses are correlated to ascertain the effect of enzymatic action on micellar aggregates and the consequential guest release. The release of the guest molecule is conveniently tuned by stabilizing the micellar aggregates through photochemical crosslinking of hydrophobic coumarin units. This photo‐crosslinking is also utilized as a tool to investigate the mode of enzyme–substrate interaction in the context of aggregate–monomer equilibrium.
An Efficient, Overall [4+1] Cycloadditon of 1,3‐Dienes and Nitrene Precursors
Authors: Wu Qiong , Hu Jian , Ren Xinfeng , Zhou Jianrong (Steve) 
Published: September 2011

AbstractIntermolecular cycloadditions of conjugated dienes and nitrene precursors usually produce aziridines. A generally useful method was lacking to directly provide the [4+1] cycloadducts, 3‐pyrrolines. We have realized this transformation by using an uniquely active catalyst, copper(II) 1,1,1,5,5,5‐hexafluoroacetylacetonate ([Cu(hfacac)2]). The method is applicable to a wide array of dienes with good yields. When 1,4‐disubsituted dienes are used as substrates, good‐to‐excellent cis or trans selectivity can be obtained. Interestingly, the cis or trans preference depends on the nature of the substituents, rather than diene geometry. Mechanistic studies reveal that the [4+1] cycloaddition proceeds through diene aziridination and subsequent ring expansion. Among common copper catalysts, only [Cu(hfacac)2] can efficiently catalyze both steps, which explains the unique efficiency of the catalyst.
BINAP versus BINAP(O) in Asymmetric Intermolecular Mizoroki–Heck Reactions: Substantial Effects on Selectivities
Authors: Wöste Thorsten H. , Oestreich Martin 
Published: September 2011

Abstract2,2′‐Bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) was employed as chiral ligand in the enantioselective intermolecular Mizoroki–Heck reaction, whereas the use of cognate BINAP(O) (monooxidized BINAP) is unprecedented. The regio‐ and enantioselectivity of the arylation of representative cyclic alkenes changes dramatically in the presence of hemilabile BINAP(O) instead of BINAP. The arylation of 2,3‐dihydrofuran is perfectly regiodivergent (98:2 versus 0:100) and the arylation of cyclopentene is only enantioselective with BINAP(O) [60 versus 10 % enantiomeric excess (ee)]. Use of [Pd2(dba)3]⋅dba (dba=dibenzylideneacetone) instead of Pd(OAc)2 produces as high as 86 % ee in the arylation of cyclopentene.
β‐Sheet‐Induced Chirogenesis in Polymerization of Oligopeptides
Authors: Wagner Nathaniel , Rubinov Boris , Ashkenasy Gonen 
Published: September 2011

AbstractThe origin of long homochiral biopolymers in living systems has recently been the focus of intense research. In one particular research line, scientists studied, experimentally and theoretically, chiral amplification obtained during peptide formation by polymerization of amino acid building blocks. It was suggested that processes leading to temporal or spatial separation, and thus, to the growth of homochiral polymers at the expense of their heterochiral counterparts, can explain the chirality observed in larger molecules. We introduce a simple model and stochastic simulation for the polymerization of amino acids and β‐sheet formation, showing the crucial effects of the β sheets on the distributions of peptide lengths. When chiral affinities are included, racemic β sheets of alternating homochiral strands lead to the formation of chiral peptides, the isotacticity of which increases with length, consistent with previous experimental results in aqueous solutions. The tendency to form isotactic peptides is shown for both initially racemic and initially nonracemic systems, as well as for closed and open systems. We suggest that these or similar mechanisms may explain the origin of chiroselectivity in prebiotic environments.
Evaluating the effectiveness and efficacy of unguided internet‐based self‐help intervention for the prevention of depression: a randomized controlled trial
Authors: Lintvedt Ove K. , Griffiths Kathleen M. , Sørensen Kristian , Østvik Andreas R. , Wang Catharina E. A. , Eisemann Martin , Waterloo Knut 
Published: September 2011

The Internet has the potential to increase the capacity and accessibility of mental health services. This study aimed to investigate whether an unguided Internet‐based self‐help intervention delivered without human support or guidance can reduce symptoms of depression in young people at risk of depression. The study also aimed to explore the usage of such sites in a real‐life setting, to estimate the effects of the intervention for those who received a meaningful intervention dose and to evaluate user satisfaction. Young adults were recruited by means of a screening survey sent to all students at the University of Tromsø. Of those responding to the survey, 163 students (mean age 28.2 years) with elevated psychological distress were recruited to the trial and randomized to an Internet intervention condition or the waiting list control group. The Internet condition comprised a depression information website and a self‐help Web application delivering automated cognitive behavioural therapy. The participants in the waiting list condition were free to access formal or informal help as usual. Two‐thirds of the users who completed the trial initially reported an unmet need for help. The findings demonstrated that an unguided intervention was effective in reducing symptoms of depression and negative thoughts and in increasing depression literacy in young adults. Significant improvements were found at 2‐month follow up. Internet‐based interventions can be effective without tracking and thus constitute a minimal cost intervention for reaching a large number of people. User satisfaction among participants was high. Copyright © 2011 John Wiley & Sons, Ltd.Key Practitioner Message

Internet‐based self‐help can be useful for early intervention among people experiencing elevated depressive symptoms.
The present trial demonstrated that an unguided intervention can be effective in reducing depressive symptoms.
The Internet‐based intervention has the potential of reaching a target group with an unmet need for help.
Approximately 27% of users referred to the site completed on average 55% of the intervention.
Hypomanic Personality, Stability of Self‐Esteem and Response Styles to Negative Mood
Authors: Bentall Richard P. , Myin‐Germeys Inez , Smith Angela , Knowles Rebecca , Jones Steven H. , Smith Talya , Tai Sara J. 
Published: September 2011

ObjectivesThis paper aims to study dysfunctional self‐schematic processes, abnormal coping styles, over‐responsiveness to reward stimuli (indicative of an over‐sensitive behavioural activation system) and stability of self‐esteem in relation to subclinical hypomania.DesignThree cross‐sectional studies were conducted on selected students on the basis of their scores on the Hypomanic Personality Scale (HPS) (study 1) and on elevated HPS and Dysfunctional Attitude Scale scores (studies 2 and 3).MethodsIn studies 1 and 2, participants completed questionnaires and kept a self‐esteem diary for 6 days. In study 3, the experience sampling method was used to assess momentary self‐esteem, emotion and use of different coping styles over a 6‐day period.ResultsStudy 1 demonstrated that hypomanic traits are associated with high fluctuations in self‐esteem. In study 2, high scores on both the HPS and the Dysfunctional Attitude Scale, but not the HPS alone, were associated with bipolar spectrum symptoms. These participants showed more evidence of alcohol and substance abuse, greater self‐esteem fluctuation and dysfunctional coping styles (rumination and risk‐taking) compared with controls. Changes in self‐esteem were related to the use of these strategies.ConclusionsVulnerability to bipolar disorder is associated with a combination of depression‐related and reward‐related processes. Copyright © 2011 John Wiley & Sons, Ltd.
Chemical Vapor Synthesis and Characterization of Manganese Oxides
Authors: Le Hoang Anh , Chin Sungmin , Park Eunseuk , Linh Le Thuy , Bae Gwi‐Nam , Jurng Jongsoo 
Published: September 2011

AbstractManganese oxide nanoparticles are synthesized by a chemical vapor process using manganese(0) carbonyl as the precursor. The synthesis temperature of the materials is varied from 500 to 1500 °C at 200 °C intervals. These nanomaterials are characterized by X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer‐Emmett‐Teller (BET) surface area, and X‐ray photoelectron spectroscopy (XPS). XRD shows that the manganese oxide nanoparticles synthesized at 500, 700 – 1100, 1300, and 1500 °C are mainly MnO2, Mn2O3, Mn2O3/Mn3O4, and Mn3O4, respectively. The TEM and BET results also confirm that the particle size is on the nanometer scale with a large specific surface area (SSA) of 81 – 215 m2 g−1. XPS indicates the catalysts to have manganese oxidation states of (2+), (3+), or (4+) depending on the synthesis temperature.
CVD of Poly(α,α′‐dimethyl‐p‐xylylene) and Poly(α,α,α′,α′‐tetramethyl‐p‐xylylene)‐co‐poly(p‐xylylene) from Alkoxide Precursors II: Thermal Oxidative Stability
Authors: Senkevich Jay J. 
Published: September 2011

AbstractThe Achilles heel of the parylene polymers is their oxidative stability at room temperature with UV exposure and at elevated temperature >115 °C in air. This weakness is attributed to the aliphatic carbon‐carbon single bond in the main‐chain backbone. Fluorinating this chemistry helps the oxidation substantially, but the precursor then becomes nearly prohibitive to use due to cost of the precursor and the processing cost. Another option is to explore the methylation of this benzyl position. Poly(α,α′‐dimethyl‐p‐xylylene) and poly(α,α,α′,α′‐tetramethyl‐p‐xylylene)‐co‐poly(p‐xylylene) are deposited on the parylene platform via alkoxy precursors. Their oxidation as a function of temperature to 300 °C; and time at 150 °C is explored via variable angle spectroscopic ellipsometry (VASE) and infrared spectroscopy (IRS). Results show very little difference between the two polymers as a function of oxidation temperature, and better results compared to what was previously observed with the poly(p‐xylylene) homopolymer, however the oxidation of poly(α,α′‐dimethyl‐p‐xylylene) at 150 °C as a function of time is less positive with 16% thickness loss over 1000 h with the post‐deposition annealed sample.
Matrix Infrared Spectroscopy and a Theoretical Investigation of SUO and US2
Authors: Andrews Lester , Wang Xuefeng , Liang Binyong , Ruipérez Fernando , Infante Ivan , Raw Adam D. , Ibers James A. 
Published: September 2011

AbstractUS2 and SUO molecules have been prepared by laser ablation of the solid materials and reaction of the elements during condensation in solid argon, which give the same absorptions as earlier U atom reactions with sulfur vapor and sulfur dioxide. The antisymmetric stretching mode of US2 shifts from 438.7 cm–1 in solid argon to 442.3 cm–1 in solid neon, which shows that the same electronic state is trapped in both matrix environments. Density functional calculations find a bent (3B2) ground state for the US2 molecule, and CASSCF/CASPT2 calculations reveal a multiconfigurational mixture of (5fφ)1(5fδ)1‐type states, whereas the most stable state for UO2 is a linear structure of the (5fφ)(7s) type. The bent triplet ground state SUO molecule exhibits similar multireference character with the U–O stretching mode at 857.1 cm–1 in solid argon. The linear SUO molecule computed at the CASPT2 level is only 2 kcal/mol above the bent structure. A detailed analysis of the bonding in US2 and SUO is provided and compared to the better known UO2 molecule.
The Bromodiazirinyl Anion: A Weakly Bound Complex of Diazirinylidene and a Bromide Ion
Authors: Martinů Tomáš , Böhm Stanislav , Hanzlová Eva 
Published: September 2011

AbstractExperimental and computational evidence suggests that the cleavage of n‐butyl and tert‐butyl 3‐bromodiazirine‐3‐carboxylates by sodium n‐butoxide in DMF, affording high yields of dibutyl carbonates, may proceed by nucleophilic acyl displacement of the bromodiazirinyl anion, a weakly bound complex of a cyclic carbene c‐CN2 (diazirinylidene) and a bromide ion. We explain the formation of substantial amounts of di‐n‐butoxymethane in the presence of n‐butanol by a sequence of O–H insertion and denitrogenation reactions of the putative c‐CN2 carbene. This ground‐state singlet species is the last undescribed member of the CN2 family of reactive intermediates. It differs from classical N‐heterocyclic carbenes by its high ionization potential and electron affinity.
Continuous Flow Synthesis of Methanofullerenes in Microstructured Reactors: A Kinetic Study
Authors: Silvestrini Simone , Dalle Nogare Daniela , Carofiglio Tommaso , Menna Enzo , Canu Paolo , Maggini Michele 
Published: September 2011

AbstractThe kinetics of the cyclopropanation reaction of diethyl malonate with [60]fullerene were assayed to optimize the continuous flow synthesis of the methanofullerene monoadduct. Experiments were carried out under both batch and flow conditions, by sampling the reaction mixture at different times and separating the components by means of HPLC in a way that resembles a stop/quenched flow system with the addition of a chromatographic step before analysis. The observed concentration profiles of the fullerene species in the reaction mixture were used to calculate the pertinent rate constants and to optimize the selectivity towards the monoaddition product.
Human immunodeficiency virus and liver disease forum 2010: Conference proceedings
Authors: Sherman Kenneth E. , Thomas David L. , Chung Raymond T. 
Published: September 2011

Abstract

Liver disease continues to represent a critical mediator of morbidity and mortality in those with human immunodeficiency virus (HIV) infection. The frequent presence and overlap of concomitant injurious processes, including hepatitis C virus and hepatitis B virus infections, hepatoxicity associated with antiretroviral therapeutic agents, alcohol, and other toxins, in the setting of immunosuppression lead to rapid fibrotic progression and early development of end-stage liver disease. This conference summary describes the proceedings of a state-of-the-art gathering of international experts designed to highlight the status of current research in epidemiology, natural history, pathogenesis, and treatment of HIV and liver disease. (Hepatology 2011)
Characterization and evaluation of processes governing the groundwater quality in parts of the Sabarmati basin, Gujarat using hydrochemistry integrated with GIS
Authors: Rina Kumari , Datta P. S. , Singh Chander Kumar , Mukherjee Saumitra 
Published: September 2011

AbstractIntense agricultural and industrial activities in any area are likely to make groundwater vulnerable with respect to its quality. In one such area which is a part of Sabarmati river basin of Gujarat, factors influencing the groundwater hydrochemistry in pre‐ and post‐monsoon season were evaluated. Groundwater samples were collected from 5 km × 5 km grids on the basis of spectral signature of vegetation and soil, observed on satellite image. Integration of Conventional graphical plots, Piper plot, saturation index values (estimated using PHREEQC) and GIS was helpful not only to create the database for analysis of spatial variation in respective water quality parameters but also to decipher the hydrogeochemical process occurring in such a large area. USSL diagram and % sodium were used to characterise the suitability of groundwater for irrigation. It was observed that leaching of wastes disposed from anthropogenic activities and agrichemicals is the major factor influencing the groundwater quality, in addition to the natural processes such as weathering, dissolution and ion exchange. Sea water relics are also impacting the groundwater quality. Control of indiscriminate and unplanned exploitation of groundwater, application of fertilizers and disposal of industrial wastes in the affected areas can possibly ensure groundwater protection from further pollution and depletion. Copyright © 2011 John Wiley & Sons, Ltd.
Impact of anticipated climate change on direct groundwater recharge in a humid tropical basin based on a simple conceptual model
Authors: Thampi Santosh G. , Raneesh K. Y. 
Published: September 2011

AbstractA simple conceptual semi‐distributed modelling approach for assessing the impacts of climate change on direct groundwater recharge in a humid tropical river basin is investigated. The study area is the Chaliyar river basin in the state of Kerala, India. Many factors affecting future groundwater recharge include decrease or increase in precipitation and temperature regimes, coastal flooding, urbanization and changes in land use. The model is based on the water‐balance concept and links the atmospheric and hydrogeologic parameters to different hydrologic processes. It estimates daily water‐table fluctuation and is calibrated and validated using 10 years of data. Data for the first 6 years (2000 to 2005) is used for model calibration, and data for the remaining four years (2006 to 2009) is used for validation. For assessing the impact of predicted climate change on groundwater recharge during the period 2071–2100, temperature and precipitation data in two post climate change scenarios, A2 and B2, were predicted using the Regional Climate Model (RCM), PRECIS (Providing Regional Climates for Impact Studies). These data were then corrected for biases and used in a hydrologic model to predict groundwater recharge in the post climate change scenario. Due to lack of reliable data and proper knowledge as to the magnitude and extent of future climatic changes, it may not be possible to include all the possible effects quantitatively in groundwater recharge modelling. However, the study presents a scientific method to assess the impact of predicted climate change on groundwater recharge and would help engineers, hydrologists, administrators and planners to devise strategies for the efficient use as well as conservation of freshwater resources. Copyright © 2011 John Wiley & Sons, Ltd.
Application of data assimilation with the Root Zone Water Quality Model for soil moisture profile estimation in the upper Cedar Creek, Indiana
Authors: Han Eunjin , Merwade Venkatesh , Heathman Gary C. 
Published: September 2011

AbstractData assimilation techniques have been proven as an effective tool to improve model forecasts by combining information about observed variables in many areas. This article examines the potential of assimilating surface soil moisture observations into a field‐scale hydrological model, the Root Zone Water Quality Model, to improve soil moisture estimation. The Ensemble Kalman Filter (EnKF), a popular data assimilation technique for nonlinear systems, was applied and compared with a simple direct insertion method. In situ soil moisture data at four different depths (5, 20, 40, and 60 cm) from two agricultural fields (AS1 and AS2) in northeastern Indiana were used for assimilation and validation purposes. Through daily update, the EnKF improved soil moisture estimation compared with the direct insertion method and model results without assimilation, having more distinct improvement at the 5 and 20 cm depths than for deeper layers (40 and 60 cm). Local vertical soil property heterogeneity in AS1 deteriorated soil moisture estimates with the EnKF. Removal of systematic bias in the forecast model was found to be critical for more successful soil moisture data assimilation studies. This study also demonstrates that a more frequent update generally contributes in enhancing the open loop simulation; however, large forecasting error can prevent more frequent update from providing better results. In addition, results indicate that various ensemble sizes make little difference in the assimilation results. An ensemble of 100 members produced results that were comparable with results obtained from larger ensembles. Copyright © 2011 John Wiley & Sons, Ltd.
A prospective, population‐based study of 40,000 women regarding host factors, UV exposure and sunbed use in relation to risk and anatomic site of cutaneous melanoma
Authors: Nielsen Kari , Måsbäck Anna , Olsson Håkan , Ingvar Christian 
Published: September 2011

AbstractProspective cohort studies about cutaneous melanoma (CM) risk are still few. Host factor‐ and UVR exposure data were collected prospectively by questionnaire in this population‐based cohort study including 40,000 Swedish born women, aged 25–64 years at enrolment (1990). Risk for CM (Cox regression and Stepwise Cox regression [SCR], hazard ratios [HRs] with 95% Confidence Intervals [CI]) in relation to risk factors, age groups (older or younger than 40 years) and primary site, were analyzed. In 29,520 women with complete follow‐up through 2007, 155 invasive and 60 in
situ CM were recorded. High numbers of nevi (HR, 2.9; 95% CI, 1.7–5.0) and heredity (HR, 3.7; 95% CI, 2.0–6.8) were associated with risk for CM. SCR analysis added red hair as a risk factor. Sunbed use >10 times/year increased risk for women <40 years (HR, 2.5; 95% CI, 1.0–6.2) and a trend for risk associated with sunbathing vacations (HR, 1.4; 95% CI, 1.0–2.0) was shown for women >40 years. Trunk melanoma showed correlations with high numbers of nevi (HR, 3.0; 95% CI, 1.2–7.3) and heredity (HR, 3.2; 95% CI, 1.1–9.4). Head/neck site was correlated to sunbathing vacations (HR, 2.5; 95% CI, 1.2–5.3) and heredity (HR, 7.6; 95% CI, 1.8–31.8). Our study supports divergent etiologic pathways to CM, with high numbers of nevi correlated to increased risk for trunk CM. Furthermore, it confirms that high numbers of nevi, red hair and heredity for CM are the most important risk factors and frequent sunbed use might be a risk factor for younger women.