bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collective behavior in cancer cell populations
Authors: Deisboeck Thomas S. , Couzin Iain D. 
Published: February 2009

AbstractIn recent years the argument has been made that malignant tumors represent complex dynamic and self‐organizing biosystems. Furthermore, there is increasing evidence that collective cell migration is common during invasion and metastasis of malignant tumors. Here, we argue that cancer systems may be capable of developing multicellular collective patterns that resemble evolved adaptive behavior known from other biological systems including collective sensing of environmental conditions and collective decision‐making. We present a concept as to how these properties could arise in tumors and why the emergence of such swarm‐like patterns would confer advantageous properties to the spatiotemporal expansion of tumors, and consequently, why understanding and ultimately targeting such collectivity should be of interest for basic and clinical cancer research alike.
Distinguishing heat from light in debate over controversial fossils
Authors: Donoghue Philip C. J. , Purnell Mark A. 
Published: February 2009

AbstractFossil organisms offer our only direct insight into how the distinctive body plans of extant organisms were assembled. However, realizing the potential evolutionary significance of fossils can be hampered by controversy over their interpretation. Here, as a guide to evaluating palaeontological debates, we outline the process and pitfalls of fossil interpretation. The physical remains of controversial fossils should be reconstructed before interpreting homologies, and choice of interpretative model should be explicit and justified. Extinct taxa lack characters diagnostic of extant clades because the characters had not yet evolved, because of secondary loss, or because they have rotted away. The latter, if not taken into account, will lead to the spurious assignment of fossils to basally branching clades. Conflicting interpretations of fossils can often be resolved by considering all the steps in the process of anatomical analysis and phylogenetic placement, although we must accept that some fossil organisms are simply too incompletely preserved for their evolutionary significance to be realized.
What are genes “for” or where are traits “from”? What is the question?
Authors: Buchanan Anne V. , Sholtis Samuel , Richtsmeier Joan , Weiss Kenneth M. 
Published: February 2009

AbstractFor at least a century it has been known that multiple factors play a role in the development of complex traits, and yet the notion that there are genes “for” such traits, which traces back to Mendel, is still widespread. In this paper, we illustrate how the Mendelian model has tacitly encouraged the idea that we can explain complexity by reducing it to enumerable genes. By this approach many genes associated with simple as well as complex traits have been identified. But the genetic architecture of biological traits, or how they are made, remains largely unknown. In essence, this reflects the tension between reductionism as the current “modus operandi” of science, and the emerging knowledge of the nature of complex traits. Recent interest in systems biology as a unifying approach indicates a reawakened acceptance of the complexity of complex traits, though the temptation is to replace “gene for” thinking by comparably reductionistic “network for” concepts. Both approaches implicitly mix concepts of variants and invariants in genetics. Even the basic question is unclear: what does one need to know to “understand” the genetic basis of complex traits? New operational ideas about how to deal with biological complexity are needed.
Mammalian fertilization: the strange case of sperm protein 56
Authors: Wassarman Paul M. 
Published: February 2009

AbstractDuring mammalian fertilization sperm bind to the egg's zona pellucida (ZP) after undergoing capacitation. Capacitated mouse sperm bind to mZP3 (one of three ZP glycoproteins), undergo the acrosome reaction, penetrate the ZP, and fuse with egg plasma membrane. Sperm protein 56 (sp56), a member of the C3/C4 superfamily of binding proteins, was identified nearly 20 years ago as a binding partner for mZP3 by photoaffinity cross‐linking of acrosome‐intact sperm. However, subsequent research revealed that sp56 is a component of the sperm's acrosomal matrix and, for sperm with an intact acrosome, should be unavailable for binding to mZP3. Recently, this dilemma was resolved when it was recognized that some acrosomal matrix (AM) proteins, including sp56, are released to the sperm surface during capacitation. This may explain why uncapacitated mammalian sperm are unable to bind to the unfertilized egg ZP.
Thermodynamic analysis of biodegradation pathways
Authors: Finley Stacey D. , Broadbelt Linda J. , Hatzimanikatis Vassily 
Published: February 2009

AbstractMicroorganisms provide a wealth of biodegradative potential in the reduction and elimination of xenobiotic compounds in the environment. One useful metric to evaluate potential biodegradation pathways is thermodynamic feasibility. However, experimental data for the thermodynamic properties of xenobiotics is scarce. The present work uses a group contribution method to study the thermodynamic properties of the University of Minnesota Biocatalysis/Biodegradation Database. The Gibbs free energies of formation and reaction are estimated for 914 compounds (81%) and 902 reactions (75%), respectively, in the database. The reactions are classified based on the minimum and maximum Gibbs free energy values, which accounts for uncertainty in the free energy estimates and a feasible concentration range relevant to biodegradation. Using the free energy estimates, the cumulative free energy change of 89 biodegradation pathways (51%) in the database could be estimated. A comparison of the likelihood of the biotransformation rules in the Pathway Prediction System and their thermodynamic feasibility was then carried out. This analysis revealed that when evaluating the feasibility of biodegradation pathways, it is important to consider the thermodynamic topology of the reactions in the context of the complete pathway. Group contribution is shown to be a viable tool for estimating, a priori, the thermodynamic feasibility and the relative likelihood of alternative biodegradation reactions. This work offers a useful tool to a broad range of researchers interested in estimating the feasibility of the reactions in existing or novel biodegradation pathways. Biotechnol. Bioeng. 2009;103: 532–541. © 2009 Wiley Periodicals, Inc.
Stem cells in microfluidics
Authors: van Noort Danny , Ong Siew Min , Zhang Chi , Zhang Shufang , Arooz Talha , Yu Hanry 
Published: February 2009

AbstractWith the introduction of microtechnology and microfluidic platforms for cell culture, stem cell research can be put into a new context. Inside microfluidics, microenvironments can be more precisely controlled and their influence on cell fate studied. Microfluidic devices can be made transparent and the cells monitored real time by imaging, using fluorescence markers to probe cell functions and cell fate. This article gives a perspective on the yet untapped utility of microfluidic devices for stem cell research. It will guide the biologists through some basic microtechnology and the application of microfluidics to cell research, as well as highlight to the engineers the cell culture capabilities of microfluidics. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Selective monosulfoxidation of tetrathiafulvalenes into chiral TTF‐sulfoxides
Authors: Chas Marcos , Riobé François , Sancho Raquel , Minguíllon Cristina , Avarvari Narcis 
Published: February 2009

AbstractFour inner tetrathiafulvalene‐sulfoxides have been synthesized upon reaction of tetrathiafulvalene (TTF), tetramethyl‐tetrathiafulvalene (TMTTF), tetrakis (thiomethyl)‐tetrathiafulvalene (TMT‐TTF), and bis(ethylenedithio)‐tetrathiafulvalene (BEDT‐TTF) with enantiopure (+) or (−)‐(8,8‐dichlorocamphorylsulfonyl)‐oxaziridine as oxidizing agent. Chiral HPLC studies indicate very weak enantioselectivities for TTF‐SO 3 and TMTTF‐SO 4, formation of racemic mixture in the case of TMT‐TTF‐SO 5, and a rather good selectivity, up to 44% ee, in the case of BEDT‐TTF‐SO 1. The solid state structures of TMTTF‐SO 4 and TMT‐TTF‐SO 5 have been determined by single crystal X‐ray diffraction. Both compounds crystallize as racemates in the centrosymmetric triclinic space group P‐1. Theoretical calculations at DFT/B3LYP/6‐31+G* level afford optimized geometries in good accordance with the experimental structures and emphasize the participation of the chiral sulfoxide group in HOMO and LUMO. Time‐dependent DFT calculations corroborated with electronic circular dichroism spectra allow the assignment of the absolute configuration (R) for the major enantiomer of 1 when the (+)‐sulfonyl‐oxaziridine is used as oxygen transfer reagent. Preliminary semipreparative HPLC separation provided enantioenriched fractions up to 63% ee. Chirality, 2009. © 2009 Wiley‐Liss, Inc.
Diastereomeric resolution of p‐chloromandelic acid with (R)‐phenylethylamine
Authors: He Quan , Peng Yang‐Feng , Rohani Sohrab 
Published: February 2009

AbstractThe optical resolution of p‐chloromandelic acid using (R)‐α‐phenylethylamine as resolving agent was presented. The effect of solvents, molar ratio of racemate to the resolving agent, filtration temperature as well as the amount of solvent on resolution was investigated by orthogonal experimentation. The binary melting point phase diagram and crystal structure analysis of diastereomeric salts rationalized the success of the resolution. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Bistable traveling waves around an obstacle
Authors: Berestycki Henri , Matano Hiroshi , Hamel François 
Published: February 2009

AbstractWe consider traveling waves for a nonlinear diffusion equation with a bistable or multistable nonlinearity. The goal is to study how a planar traveling front interacts with a compact obstacle that is placed in the middle of the space ℝN. As a first step, we prove the existence and uniqueness of an entire solution that behaves like a planar wave front approaching from infinity and eventually reaching the obstacle. This causes disturbance on the shape of the front, but we show that the solution will gradually recover its planar wave profile and continue to propagate in the same direction, leaving the obstacle behind. Whether the recovery is uniform in space is shown to depend on the shape of the obstacle. © 2008 Wiley Periodicals, Inc.
Temperature Dependence of the Dielectric Properties and Dynamics of Ionic Liquids
Authors: Hunger Johannes , Stoppa Alexander , Schrödle Simon , Hefter Glenn , Buchner Richard 
Published: February 2009

AbstractNo solo dancers: The temperature dependence of dielectric spectra suggests that the lower‐frequency relaxation dominating the dynamics of imidazolium‐based room temperature ionic liquids cannot be solely due to independent rotational diffusion of the cations (see picture), but must also include cooperative motions of the surrounding particles.magnified imageDielectric spectra were measured for eight, mostly imidazolium‐based, room temperature ionic liquids (RTILs) over a wide range of frequencies (0.2≤ν/GHz≤89) and temperatures (5≤θ/°C≤ 65). Detailed analysis of the spectra shows that the dominant low frequency process centred at ca. 0.06 to 10 GHz (depending on the salt and the temperature) is better described using a symmetrically broadened Cole–Cole model rather than the asymmetric Cole–Davidson models used previously. Evaluation of the temperature dependence of the static permittivities, effective dipole moments, volumes of rotation, activation energies, and relaxation times derived from the dielectric data indicates that the low frequency process cannot be solely due to rotational diffusion of the dipolar imidazolium cations, as has been thought, but must also include other contributions, probably from cooperative motions. Analysis of the Debye process observed at higher frequencies for these RTILs is not undertaken because it overlaps with even faster processes that lie outside the range of the present instrumentation.
The reductionist blind spot
Authors: Abbott Russ 
Published: February 2009

AbstractCan there be higher level laws of nature even though everything is reducible to the fundamental laws of physics? The computer science notion of level of abstraction explains how there can be. The key relationship between elements on different levels of abstraction is not the is‐composed‐of relationship but the implements relationship. I take a scientific realist position with respect to (material) levels of abstraction and their instantiation as (material) entities. They exist as objective elements of nature. Reducing them away to lower order phenomena produces a reductionist blind spot and is bad science. © 2009 Wiley Periodicals, Inc. Complexity, 2009.
Multi‐factors oriented study of P2P Churn
Authors: Yang Dong , Zhang Yu‐xiang , Zhang Hong‐ke , Wu Tin‐Yu , Chao Han‐Chieh 
Published: February 2009

AbstractThe dynamics of peers, namely Churn, is an inherent property of peer‐to‐peer (P2P) systems and is critical to their design and evaluation. Although every excellent P2P protocol has some solution to this issue, studies on Churn are still seldom. This paper studies various factors related to Churn, and uses them to analyze and evaluate P2P protocols. Prior researches on Churn are all based on the P2P network factors in Churn environment, and their difference is whether to use these factors as predecessor references to build Churn analytical models or as successor references to test the models. According to this difference, this paper first divides various factors into two categories: impacting Churn and affected by Churn. There is a causal relationship between these two categories. Factors impacting Churn are cause, and the factors affected by Churn are effect. In this paper, we use this causality to simulate and analyze P2P Churn. Cause is used as the input data and effect is used as the output result. Second, based on the classification of Churn factors, we present a performance evaluation framework and two comparing models. Based on the framework and models, we simulate and analyze three P2P protocols and get some useful results such as the performance of these protocols under Churn, the advantage of Chord over others, and the most important factors impacting Churn. Finally, we present a method to improve recent P2P Churn models by adding some influence factors. Copyright © 2009 John Wiley & Sons, Ltd.
Review of the effects of 17α‐estradiol in humans: a less feminizing estrogen with neuroprotective potential
Authors: Moos Walter H. , Dykens James A. , Nohynek Dana , Rubinchik Evelina , Howell Neil 
Published: February 2009

Abstract17α‐Estradiol is a less feminizing isomer of the potent hormonal estrogen, 17β‐estradiol. 17α‐Estradiol is an orally active small molecule with conflicting reports of efficacy in preclinical models of degenerative diseases. A number of studies suggest neuroprotective potential in human neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease. Several studies have established an antioxidant effect of 17α‐estradiol in humans. The sodium salt of 17α‐estradiol 3‐sulfate is a minor component (2.5–9.5%) of several widely marketed estrogen hormone replacement products, such as Premarin®, that are approved by the U.S. Food and Drug Administration and have been prescribed and studied in women and men for more than 65 years. Most of the more than 100 published reports on the neurological effects of feminizing estrogens found positive responses in at least one measure relating to cognition or prevention and treatment of AD, notwithstanding the negative results in the Women's Health Initiative studies. Whether these limited, and often not statistically significant, findings are clinically meaningful remains unknown. In many in vitro and in vivo preclinical neuroprotection and related studies, 17α‐estradiol and 17β‐estradiol are active at similar concentrations and doses. However, 17α‐estradiol is less pleiotropic than 17β‐estradiol, and thus its potential toxicity might be lower. Given decades of mixed reports regarding the potential efficacy and safety of strongly feminizing hormones in neurodegenerative diseases, the weakly feminizing 17α‐estradiol might be a suitable candidate for clinical testing of the neuroprotective potential of this chemical class because it avoids, or significantly reduces, the adverse effects of potent hormonal compounds. Drug Dev Res 70:1–21, 2009. © 2009 Wiley‐Liss, Inc.
Prevalence and correlates of exercise motivated by negative affect
Authors: De Young Kyle P. , Anderson Drew A. 
Published: February 2009

AbstractObjectiveThe purpose of this study was to determine the prevalence and correlates of exercising in response to negative affect.MethodParticipants (N = 177) completed questionnaires assessing affect before and after exercise, exercise quality and quantity, eating behaviors and attitudes, body image, and self‐esteem.ResultsFifty‐eight percent of participants endorsed ever exercising in response to negative affect. As a group, these individuals were more likely to report self‐induced vomiting, binge eating, and fasting over the previous 4 weeks. They also showed poorer body image and self‐esteem, and their exercise was more obligatory and impairing. Groups did not differ on body mass index or quantity of exercise.DiscussionNegative affect motivated exercise appears to be a common phenomenon that is associated with eating disordered behavior. © 2009 by Wiley Periodicals, Inc. Int J Eat Disord 2010
Nonionic surfactant‐capped gold nanoparticles for selective enrichment of aminothiols prior to CE with UV absorption detection
Authors: Li Mu‐De , Cheng Tian‐Lu , Tseng Wei‐Lung 
Published: February 2009

AbstractIn this study, we describe the use of Tween 20‐capped gold nanoparticles (AuNPs) as selective probes for the extraction of aminothiols from an aqueous solution. Tween 20 molecules noncovalently attached to the surface of AuNPs to form Tween 20–AuNPs were used for the selective extraction of aminothiols through the formation of Au–S bonds. After extraction and centrifugation, the aminothiols were detached from the surface of the AuNPs by adding DTT in a high concentration. We used this probe in combination with CE and UV absorption detection. On‐line concentration and separation of the released aminothiols were performed by using 1.6% v/v poly(diallyldimethylammonium chloride) as an additive in CE. Under optimal extraction and stacking conditions, the LOD at a S/N of 3 were 28, 554, and 456 nM for glutathione (GSH), cysteine (Cys), and homocysteine (HCys), respectively. In comparison with the normal injection without the extraction procedure, approximately 2280‐, 998‐, and 904‐fold improvements in the sensitivity were observed for GSH, Cys, and HCys, respectively. We have validated the application of our method on the basis of the analysis of GSH and HCys in human urine samples. It is believed that this approach has significant potential to be extended to clinical diagnosis.
Laboratory performance tests on aluminum splices for power conductors
Authors: Runde M. , Timsit R. S. , Magnusson N. 
Published: February 2009

AbstractThe paper reviews the results of laboratory testing of compression and bolted splices installed on stranded aluminum power conductors. The tests on compression splices involved connectors of 10 different designs using 240 mm2stranded aluminum cable. Testing on the bolted splices was performed on connectors of 16 different designs installed on stranded aluminum cable with dimensions of 50 and 240 mm2. Splice performance was assessed on the basis of resistance measurements during short‐circuit tests and thermal cycling as specified by the International Electrotechnical Commission (IEC) 61238‐1 standard, and from inspections of cross‐sectioned connections. Differences in splice performance are related to such factors as physical properties of the materials in contact, splice assembly procedures, number of compression indentations or number of bolts, and other relevant parameters. The influence of conductor deformation on the ability to disrupt aluminum oxide films on the conductor surface during connector installation is addressed. The laboratory data indicate that large mechanical deformations in a splice significantly improve connector performance. For compression splices, relatively soft (annealed) conductors lead to inferior performance than hard‐drawn conductors, unless the soft conductor hardens significantly when it is deformed during installation. The sequence in which the compression indentations are made may influence connector performance. Copyright © 2009 John Wiley & Sons, Ltd.
The association of serotonin transporter genotypes and selective serotonin reuptake inhibitor (SSRI)‐associated sexual side effects: possible relationship to oral contraceptives
Authors: Bishop Jeffrey R. , Ellingrod Vicki L. , Akroush Michael , Moline Jessica 
Published: February 2009

AbstractObjectiveTo study the relationship between functional variants in the serotonin transporter gene (SLC6A4) and selective serotonin reuptake inhibitor (SSRI)‐associated sexual dysfunction.MethodsOne hundred fifteen subjects aged 18–40 years and currently being treated with an SSRI for depression were assessed for clinical variables known to affect sexual well‐being. SSRI‐associated sexual difficulties were assessed with the Changes in Sexual Functioning Questionnaire (CSFQ). Subjects were subsequently genotyped for the SLC6A4 promoter region (5HTTLPR) insertion/deletion variant and a variable number of tandem repeats (VNTR) in the second intron.ResultsThe 5HTTLPR insertion/deletion variant was associated with sexual dysfunction in this study sample [odds ratio (OR) = 2.7; 95% confidence interval (CI) 1.2, 6.4; p = 0.02]. The relationship between promoter genotypes and sexual well‐being differed in males and females and was related to whether females were taking an oral contraceptive (OC) medication. Females with the ll genotype were nearly eight times more likely to be categorized as having sexual dysfunction if they were taking OCs, while no relationship was observed in those not taking OCs.ConclusionsThese results suggest that a functional variant in the serotonin transporter gene is associated with sexual difficulties in persons taking an SSRI for depression. This relationship may differ by sex and be dependent on OC status in females. Copyright © 2009 John Wiley & Sons, Ltd.
SED1/MFG‐E8: A Bi‐Motif protein that orchestrates diverse cellular interactions
Authors: Raymond Adam , Ensslin Michael A. , Shur Barry D. 
Published: February 2009

AbstractMFG‐E8 was initially identified as a principle component of the Milk Fat Globule, a membrane‐encased collection of proteins and triglycerides that bud from the apical surface of mammary epithelia during lactation. It has since been independently identified in many species and by many investigators and given a variety of names, including p47, lactadherin, rAGS, PAS6/7, and BA‐46. The acronym SED1 was proposed to bring cohesion to this nomenclature based upon it being a Secreted protein that contains two distinct functional domains: an N‐terminal domain with two EGF‐repeats, the second of which has an integrin‐binding RGD motif, and a C‐terminal domain with two Discoidin/F5/8C domains that bind to anionic phospholipids and/or extracellular matrices. SED1/MFG‐E8 is now known to participate in a wide variety of cellular interactions, including phagocytosis of apoptotic lymphocytes and other apoptotic cells, adhesion between sperm and the egg coat, repair of intestinal mucosa, mammary gland branching morphogenesis, angiogenesis, among others. This article will explore the various roles proposed for SED1/MFG‐E8, as well as its provocative therapeutic potential. J. Cell. Biochem. 106: 957–966, 2009. © 2009 Wiley‐Liss, Inc.