bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accurate quantification of water–macromolecule exchange induced frequency shift: Effects of reference substance
Authors: Leutritz Tobias , Hilfert Liane , Smalla Karl‐Heinz , Speck Oliver , Zhong Kai 
Published: February 2012

AbstractWater–macromolecule exchange induces a bulk water frequency shift contributing to the contrast in phase imaging. For separating the effects of the water–macromolecule exchange and the macromolecule susceptibility, appropriate internal or external references are needed. In this study, two internal reference compounds, 2,2,3,3‐tetradeuterio‐3‐trimethylsilyl‐propionate (TMSP) and 1,4‐dioxane, were used to study the macromolecule‐dependent water frequency shift in a bovine serum albumin (BSA)–water system in detail. For TMSP, the water–macromolecule exchange shift depended on both the BSA and the reference concentration and stabilized to a value of 0.025 ppm/mM (298 K, TMSP concentrations > 30 mM). For dioxane, the dependency of the water–macromolecule exchange shift on the BSA concentration is independent of dioxane at low concentrations. The resulting shift was smaller (0.009 ppm/mM) when compared with using higher TMSP concentrations as reference. This discrepancy might be due to additional dioxane–water interactions. Measurements with an external chloroform reference in a coaxial geometry showed a shift of −0.013 ppm/mM resulting from the opposing effects of macromolecules in water exchange‐induced shift and diamagnetic susceptibility shift. All these effects should be considered in the interpretation of tissue phase contrast. From the experimental data, the equilibrium binding constant between BSA and TMSP has been quantified to be Kd = 1.3 ± 0.4, and the estimated number of interaction sites for BSA is 12.7 ± 2.6. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Women with pure stress urinary incontinence symptoms assessed by the initial standard evaluation including measurement of post‐void residual volume and a stress test: Are urodynamic studies still needed?
Authors: Jeong Seong Jin , Kim Hyeon June , Lee Byung Ki , Rha Woong , Oh Jong Jin , Jeong Chang Wook , Kim Jeong Hyun , Yoon Cheol Yong , Hong Sung Kyu , Byun Seok‐Soo , Lee Sang Eun 
Published: February 2012

AbstractAimsThe significance of preoperative urodynamic studies in women with a “clinically‐defined pure stress urinary incontinence (SUI) symptom” has been debated in recent years. We evaluated changes of reliability of pure SUI symptoms for prediction of pure urodynamic SUI (USUI) when the assessment of post‐void residual (PVR) volume and a stress test, designated as the initial standard evaluation in the NICE and AUA guidelines, were added to the process for the diagnosis of pure SUI symptoms.MethodsWe reviewed records of 1,019 women aged 30–80 who underwent urodynamic study for incontinence. Criteria for pure SUI symptoms were defined as absence of overactive bladder symptoms and voiding difficulties based on a frequency–volume chart and AUA Symptom Index. We then added assessment of PVR volume and a stress test to the process for clinical diagnosis.ResultsOf subjects, 211 (20.7%) could be classified as having a pure SUI symptom. Of these, only 167 (79.1%) had pure USUI and 33 (15.7%) had detrusor overactivity. Eight (3.8%) had detrusor underactivity/bladder outlet obstruction. Sensitivity and specificity of pure SUI symptoms for pure USUI were 28.6% and 89.9%. Addition of assessment of PVR volume and a stress test resulted in an increase of predictive accuracy of only 3.6%.ConclusionsAs one‐fifth of women with pure SUI symptoms exhibit the pathophysiologies that could affect the surgical outcomes despite additional use of PVR assessment and a stress test in the clinical diagnostic process, urodynamic evaluation is considered necessary before anti‐incontinence surgery in this population. Neurourol. Urodynam. 31:508–512, 2012. © 2012 Wiley Periodicals, Inc.
Development of Stereocontrolled Palladium(II)‐Catalyzed Domino Heck/Suzuki β,α‐Diarylation Reactions with Chelating Vinyl Ethers and Arylboronic Acids
Authors: Trejos Alejandro , Odell Luke R. , Larhed Mats 
Published: February 2012

AbstractA stereoselective and 1,4‐benzoquinone‐mediated palladium(II)‐catalyzed Heck/Suzuki domino reaction involving metal coordinating cyclic methylamino vinyl ethers and a number of electronically diverse arylboronic acids has been developed and studied. Diastereomeric ratios up to 39:1 and 78 % isolated yields were obtained. The stereoselectivity of the reaction was found to be highly dependent on the nature of the arylboronic acid and the amount of water present in the reaction mixture. Thus, a domino β,α‐diarylation–reduction of chelating vinyl ethers can now be accomplished and stereochemically controlled, given that optimized conditions and an appropriate chiral auxiliary are used. To the best of our knowledge, this represents the first example of a stereoselective, oxidative Heck/Suzuki domino reaction in the literature.
Accuracy of pneumonia hospital admissions in a primary care electronic medical record database
Authors: Meropol Sharon B. , Metlay Joshua P. 
Published: February 2012

ABSTRACTPurposeWhen using electronic medical record data to study drug use, hospitalizations are markers of severe outcomes. To identify events within a specified time window, it is important to validate hospitalization diagnoses and dates. Our objective was to validate pneumonia hospitalizations and their dates identified using hospitalization codes in The Health Improvement Network (THIN), a UK primary care electronic medical record.MethodsThis cross‐sectional study used a cohort of THIN adult visits for acute nonspecific respiratory infections from June 1985 to August 2006. Pneumonia hospitalizations within 30 days after the visit were identified using THIN diagnosis and hospitalization codes; 60 participants were randomly selected for validation. Patients' general practitioners (GPs) returned de‐identified hospital summaries and consultants' letters regarding overnight hospitalizations within a 180‐day window around the THIN hospitalization. Positive predictive value (PPV) was the number of GP‐validated hospitalizations divided by THIN documented hospitalizations.ResultsGPs returned 59 of 60 patient records; 52 had confirmed hospitalizations. PPV of THIN hospitalization documentation was 88% (95%CI = 77–95). One admission was not for pneumonia; PPV of THIN‐documented pneumonia admission was 86% (95%CI = 75–94). Of 52 valid THIN hospitalizations, 50 were actually admitted within 14 days of the documented THIN date (range = −2 to +18). The absolute median difference between THIN and validated admission dates was +0.5 days, and the absolute mean difference was +3.1 days. In 16 of 52 admitted patients, the THIN admission date was the actual discharge date.ConclusionsTHIN hospitalization codes performed well in identifying acute pneumonia hospitalizations and their timing. Admission date validity might be better for conditions associated with shorter versus longer hospitalizations. Copyright © 2012 John Wiley & Sons, Ltd.
Progress in development of epoxy resin systems based on wood biomass in Japan
Authors: Koike Tsuneo 
Published: February 2012

AbstractThis article reviews the progress in the development of wood biomass origin epoxy resin system from 1960s to recent years in Japan. The methods of using wood biomass for epoxy resin systems are classified into the following three categories; one is the method of preparing lignin‐epoxy resins after applying treatments on the industrial lignin, which has been disposed in large volume, another is that of using wood as the raw material of epoxy resin system after applying treatments directly on wood, and the other is that of composing epoxy resin and/or curing agent from woody raw materials (except the industrial lignin), which are isolated and refined from wood before the treatments. Although several promising technologies have been developed and tried to be industrialized in Japan, the full‐fledged development of wood biomass‐based epoxy resin has just started when viewed as a whole. These developments will be further accelerated toward the construction of the environment harmony type and the resources circulation type societies. As the result of continuous developmental efforts, it is expected that we can look at the scene where epoxy resins are sustainably supplied in various forms even after the depletion of oil resources. POLYM. ENG. SCI.,, 2012. © 2012 Society of Plastics Engineers
Ratcheting up protein translocation with anthrax toxin
Authors: Feld Geoffrey K. , Brown Michael J. , Krantz Bryan A. 
Published: February 2012

AbstractEnergy‐consuming nanomachines catalyze the directed movement of biopolymers in the cell. They are found both dissolved in the aqueous cytosol as well as embedded in lipid bilayers. Inquiries into the molecular mechanism of nanomachine‐catalyzed biopolymer transport have revealed that these machines are equipped with molecular parts, including adjustable clamps, levers, and adaptors, which interact favorably with substrate polypeptides. Biological nanomachines that catalyze protein transport, known as translocases, often require that their substrate proteins unfold before translocation. An unstructured protein chain is likely entropically challenging to bind, push, or pull in a directional manner, especially in a way that produces an unfolding force. A number of ingenious solutions to this problem are now evident in the anthrax toxin system, a model used to study protein translocation. Here we highlight molecular ratchets and current research on anthrax toxin translocation. A picture is emerging of proton‐gradient‐driven anthrax toxin translocation, and its associated ratchet mechanism likely applies broadly to other systems. We suggest a cyclical thermodynamic order‐to‐disorder mechanism (akin to a heat‐engine cycle) is central to underlying protein translocation: peptide substrates nonspecifically bind to molecular clamps, which possess adjustable affinities; polypeptide substrates compress into helical structures; these clamps undergo proton‐gated switching; and the substrate subsequently expands regaining its unfolded state conformational entropy upon translocation.
Formyl‐coenzyme A (CoA):oxalate CoA‐transferase from the acidophile Acetobacter aceti has a distinctive electrostatic surface and inherent acid stability
Authors: Mullins Elwood A. , Starks Courtney M. , Francois Julie A. , Sael Lee , Kihara Daisuke , Kappock T. Joseph 
Published: February 2012

AbstractBacterial formyl‐CoA:oxalate CoA‐transferase (FCOCT) and oxalyl‐CoA decarboxylase work in tandem to perform a proton‐consuming decarboxylation that has been suggested to have a role in generalized acid resistance. FCOCT is the product of uctB in the acidophilic acetic acid bacterium Acetobacter aceti. As expected for an acid‐resistance factor, UctB remains folded at the low pH values encountered in the A. aceti cytoplasm. A comparison of crystal structures of FCOCTs and related proteins revealed few features in UctB that would distinguish it from nonacidophilic proteins and thereby account for its acid stability properties, other than a strikingly featureless electrostatic surface. The apparently neutral surface is a result of a “speckled” charge decoration, in which charged surface residues are surrounded by compensating charges but do not form salt bridges. A quantitative comparison among orthologs identified a pattern of residue substitution in UctB that may be a consequence of selection for protein stability by constant exposure to acetic acid. We suggest that this surface charge pattern, which is a distinctive feature of A. aceti proteins, creates a stabilizing electrostatic network without stiffening the protein or compromising protein–solvent interactions.
Link adaptation for Ka band low Earth orbit Earth Observation systems: A realistic performance assessment
Authors: Toptsidis Nikolaos , Arapoglou Pantelis‐Daniel , Bertinelli Massimo 
Published: February 2012

SUMMARYIn this paper, a proposal is sketched for realizing high data rate downlinks in next‐generation Ka band low Earth orbit (LEO) Earth Observation (EO) systems. The work aims at realistically assessing the throughput advantage stemming from link adaptation strategies—embraced by most wireless and satellite communication standards—compared with non‐adaptive transmission, which is the approach followed in conventional X band EO systems. The transmission strategies examined include constant, (static and dynamic) variable, and adaptive flavors of coding and modulation, each representing a different performance/system complexity trade‐off. Practicality is pursued to the extent possible by incorporating state‐of‐the‐art orbital, ground station, spacecraft, propagation, physical layer, and system implementation characteristics. The results manifest that under particular conditions, link adaptation offers throughput improvements of up to 100% against non‐adaptive transmission schemes in Ka band LEO EO systems. Copyright © 2012 John Wiley & Sons, Ltd.
A graph‐theoretic framework for isolating botnets in a network
Authors: Jaikumar Padmini , Kak Avinash C. 
Published: February 2012

AbstractWe present a new graph‐based approach for the detection and isolation of botnets in a computer network. Our approach depends primarily on the temporal co‐occurrences of malicious activities across the computers in a network and is independent of botnet architectures and the means used for their command and control. As practically all aspects of how a botnet manifests itself in a network—such as the online bot population, bot lifetimes, and the duration and the choice of malicious activities ordered by the bot master—can be expected to vary significantly with time, our approach includes mechanisms that allow the graph representing the infected computers to evolve with time. With regard to how such a graph varies with time, of particular importance are the edge weights that are derived from the temporal co‐occurrences of malicious activities at the endpoints of the edges. A unique advantage of our graph‐based representation of the infected computers is that it allows us to use graph‐partitioning algorithms to separate out the different botnets when a network is infected with multiple botnets at the same time. We have validated our approach by applying it to the isolation of simulated botnets, with the simulations based on a new unified temporal botnet model that incorporates the current best understanding about how botnets behave, about the lifetimes of bots, and about the growth and decay of botnets. We also validate our algorithm on real network traces. Our results indicate that our framework can isolate botnets in a network under varying conditions with a high degree of accuracy. Copyright © 2012 John Wiley & Sons, Ltd.
Low (linear) teacher effect on student achievement in pre‐academic physics education
Authors: Cottaar Alice 
Published: February 2012

AbstractThis study investigates the effect of physics education on students' achievement in a large‐scale quantitative study of pre‐academic high school students throughout the Netherlands. Two aspects of teacher characteristics as perceived by their students are included: their “pleasantness” principally defined by their perceived friendliness and positive feedback and their “centeredness” principally defined by the perceived teacher centeredness in the lessons. Furthermore, this study includes four student aspects: their “general capability,” their “quantity of work,” their “quality of work,” and their “interest in the lessons.” Structural Equation Modeling is used in order to cluster the different variables defining the perceived pleasantness and the perceived centeredness of the teacher and the general capability, interest, and learning attitudes of the students. Furthermore, interrelations among these components and students' achievement are analyzed. Eventually, a very large effect of the students' general capability (61–72%) and a remarkably smaller effect of the remaining parameters (<3%) on achievement are detected. However, one should not yet conclude that teacher effect on high‐achieving‐students' achievement is consistently low. To the contrary, these results should be seen as an incentive to consider nonlinear effects, to vary ones viewpoint and to include more/other variables. In spite of the almost negligible correlation between the measured aspects of the physics teachers and achievement, the correlations between the teacher variables and the remaining student variables are quite significant. Both the perceived pleasantness and the centeredness of the teachers have a significant effect on the interest of their students. Furthermore, the pleasantness of the teacher correlates with the quality of the students' work and the centeredness of the teacher with their quantity of work. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 465–488, 2012
Abnormal gyration of the temporal lobe and megalencephaly are typical features of thanatophoric dysplasia and can be visualized prenatally by ultrasound
Authors: Blaas H.‐G. K. , Vogt C. , Eik‐Nes S. H. 
Published: February 2012

AbstractAutopsies of fetuses with thanatophoric dysplasia (TD) have shown abnormal gyration of the temporal lobes. In addition, the head is relatively large compared with the abdomen. We evaluated by ultrasound six consecutive cases of TD at 19 + 0 to 19 + 6 gestational weeks based on last menstrual period. We observed abnormal and deep transverse sulci in the temporal lobes in all cases; these features were confirmed at autopsy. We performed biometric assessment, including biparietal diameter (BPD) and mean abdominal diameter (MAD). For each MAD value in the TD fetuses, we computed mean and SD of the corresponding BPD values from a population‐based registry in the relevant age range, and used them to calculate Z‐scores for each BPD/MAD ratio. In the general population, the average BPD/MAD ratio was 1.05. In the TD fetuses, the mean BPD was 51.5 (range, 49–54) mm, the MAD was 45 (range, 41–47) mm and the BPD/MAD ratio was 1.15 (range, 1.09–1.20). The average Z‐score of the ratios for TD fetuses was 2.44 (range, 1.05–3.39). The ratios for the TD fetuses were significantly higher than were the population ratios (P = 0.016). At autopsy, the mean brain‐to‐body weight ratio was 20.6% (range, 15.4–24.1%), which was greater than the corresponding mean ratio of 14.9% in normal fetuses. We conclude that abnormal and deep transverse gyration of the temporal lobes can be visualized by ultrasound in mid‐second‐trimester fetuses with TD. Due to megalencephaly, fetuses with TD have significantly different body proportions, with a larger BPD compared with normal fetuses. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Polarized climates: the distinctive histories of climate change and politics in the Arctic and Antarctica since the beginning of the Cold War
Authors: Luedtke Brandon , Howkins Adrian 
Published: February 2012

AbstractThis paper suggests that the Polar Regions are excellent places for thinking about historical interactions between climate change, science, and politics from the beginning of the Cold War up to the present. Since the second half of the 1940s, science has played a central role in contesting claims to political authority in both the Arctic and the Antarctic. Research conducted in the Polar Regions has made a major contribution to the science of climate change on a global scale, and research agendas have been closely connected in the two regions. Viewed from a comparative perspective, however, the historical experiences of global warming in the Arctic and Antarctica have been quite different. Climate research has suggested that warming is generally happening faster over much of the Arctic than the Antarctic. In addition, the recent histories of the two regions show that climate change in the Arctic is destabilizing politics there, whereas in Antarctica climate change is helping to reinforce the existing political structures framed by the Antarctic Treaty System (ATS). A comparative approach to the history of climate change in the Polar Regions helps to demonstrate that science, politics, and environmental change have each played important roles without making any single factor deterministic. WIREs Clim Change 2012, 3:145–159. doi: 10.1002/wcc.161This article is categorized under:

Climate, History, Society, Culture > World Historical Perspectives
Trans‐Disciplinary Perspectives > Regional Reviews
The development of causal reasoning
Authors: Kuhn Deanna 
Published: February 2012

AbstractHow do inference rules for causal learning themselves change developmentally? A model of the development of causal reasoning must address this question, as well as specify the inference rules. Here, the evidence for developmental changes in processes of causal reasoning is reviewed, with the distinction made between diagnostic causal inference and causal prediction. Also addressed is the paradox of a causal reasoning literature that highlights the competencies of young children and the proneness to error among adults. WIREs Cogn Sci 2012, 3:327–335. doi: 10.1002/wcs.1160This article is categorized under:

Psychology > Learning
Small molecule screening in zebrafish: swimming in potential drug therapies
Authors: Tamplin Owen J. , White Richard M. , Jing Lili , Kaufman Charles K. , Lacadie Scott A. , Li Pulin , Taylor Alison M. , Zon Leonard I. 
Published: February 2012

AbstractPhenotype‐driven chemical genetic screens in zebrafish have become a proven approach for both dissection of developmental mechanisms and discovery of potential therapeutics. A library of small molecules can be arrayed into multiwell plates containing zebrafish embryos. The embryo becomes a whole organism in vivo bioassay that can produce a phenotype upon treatment. Screens have been performed that are based simply on the morphology of the embryo. Other screens have scored complex phenotypes using whole mount in situ hybridization, fluorescent transgenic reporters, and even tracking of embryo movement. The availability of many well‐characterized zebrafish mutants has also enabled the discovery of chemical suppressors of genetic phenotypes. Importantly, the application of chemical libraries that already contain FDA‐approved drugs has allowed the rapid translation of hits from zebrafish chemical screens to clinical trials. WIREs Dev Biol 2012, 1:459–468. doi: 10.1002/wdev.37This article is categorized under:

Technologies > Perturbing Genes and Generating Modified Animals
Ink4‐Arf locus in cancer and aging
Authors: Sherr Charles J. 
Published: February 2012

AbstractThree tumor suppressor genes at the small (<50 kb) INK4‐ARF (CDKN2A/B) locus on human chromosome 9p21 coordinate a signaling network that depends on the activities of the retinoblastoma (RB) protein and the p53 transcription factor. Disruption of this circuitry, frequently by codeletion of INK4‐ARF, is a hallmark of cancer, begging the question of why the intimate genetic linkage of these tumor suppressor genes has been maintained in mammals despite the risk of their coinactivation. The INK4‐ARF locus is not highly expressed under normal physiologic conditions in young mammals, but its induction becomes more pronounced as animals age. Notably, INK4‐ARF is actively silenced en bloc in embryonic, fetal, and adult stem cells but becomes poised to respond to oncogenic stress signals as stem cells lose their self‐renewal capacity and differentiate, thereby providing a potent barrier to tumor formation. Epigenetic remodeling of the locus as a whole provides a mechanism for coordinating the activities of RB and p53. A hypothesis is that the INK4‐ARF locus may have evolved to physiologically restrict the self‐renewal capacities and numbers of stem and progenitor cells with the attendant consequence of limiting tissue regenerative capacity, particularly as animals age. Deletion of INK4‐ARF contributes to the aberrant self‐renewal capacity of tumor cells and occurs frequently in many forms of human cancer. WIREs Dev Biol 2012 doi: 10.1002/wdev.40For further resources related to this article, please visit the WIREs website.