bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aromatic interactions in model peptide β‐hairpins: Ring current effects on proton chemical shifts
Authors: Rajagopal Appavu , Aravinda Subrayashastry , Raghothama Srinivasarao , Shamala Narayanaswamy , Balaram Padmanabhan 
Published: November 2011

AbstractCrystal structures of eight peptide β‐hairpins in the sequence Boc‐Leu‐Phe‐Val‐Xxx‐Yyy‐Leu‐Phe‐Val‐OMe revealed that the Phe(2) and Phe(7) aromatic rings are in close spacial proximity, with the centroid–centroid distance (Rcen) of 4.4–5.4 Å between the two phenyl rings. Proton NMR spectra in chloroform and methanol solution reveal a significant upfield shift of the Phe(7) Cδ,δ′H2 protons (6.65–7.04 ppm). Specific assignments of the aromatic protons have been carried out in the peptide Boc‐Leu‐Phe‐Val‐DPro‐LPro‐Leu‐Phe‐Val‐OMe (6). The anticipated ring current shifts have been estimated from the aromatic ring geometrics observed in crystals for all eight peptides. Only one of the Cδ,δ′H proton lies in the shielding zone with rapid ring flipping, resulting in averaging between the two extreme chemical shifts. An approximate estimate of the population of conformations, which resemble crystal state orientation, may be obtained. Key nuclear Overhauser effects (NOEs) between facing Phe side chains provide support for close similarity between the solid state and solution conformation. Temperature dependence of aromatic ring proton chemical shift and line widths for peptide 6 (Boc‐Leu‐Phe‐Val‐DPro‐LPro‐Leu‐Phe‐Val‐OMe) and the control peptide Boc‐Leu‐Val‐Val‐DPro‐Gly‐Leu‐Phe‐Val‐OMe establish an enhanced barrier to ring flipping when the two Phe rings are in proximity. Modeling studies suggest that small, conformational adjustment about CαCβ (χ1) and CβCγ (χ2) bonds of both the Phe residues may be required in order to permit unhindered, uncorrelated flipping of both the Phe rings. The maintenance of the specific aromatic ring orientation in organic solvents provides evidence for significant stabilizing interaction. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 185–194, 2012.
The Eigenvalue Problem of Singular Ergodic Control
Authors: Hynd Ryan 
Published: November 2011

AbstractWe consider the problem of finding a real number λ and a function u satisfying the PDE

Here f is a convex, superlinear function. We prove that there is a unique λ* such that the above PDE has a viscosity solution u satisfying
$\lim_{|x|\rightarrow \infty}u(x)/|x|=1$. Moreover, we show that associated to λ* is a convex solution u* with D2u*∈
$\font\open=msbm10 at 10pt\def\R{\hbox{\open R}}L^{\infty}(\R^N)$
and give two min‐max formulae for λ*. λ* has a probabilistic interpretation as being the least, long‐time averaged (ergodic) cost for a singular control problem involving f. © 2011 Wiley Periodicals, Inc.
Magnetic Properties of Paddlewheels and Trinuclear Clusters with Exposed Metal Sites
Authors: Vogiatzis Konstantinos D. , Klopper Wim , Mavrandonakis Andreas , Fink Karin 
Published: November 2011

AbstractMagnetic exchange‐coupling constants of tri‐ and dinuclear transition‐metal complexes (paddlewheels) have been computed using various ab initio methods. The di‐ and trinuclear complexes under study may serve as secondary building units in metal‐organic frameworks (MOFs). Multi‐reference methods such as the complete‐active‐space self‐consistent‐field method (CASSCF) as well as second‐order perturbation theory (CASPT2) yield spin ladders from which the magnetic exchange‐coupling constants are obtained. For the dicobalt paddlewheels, inclusion of spin–orbit coupling is crucial for obtaining a qualitatively correct description of the system. Density functional theory (DFT) was applied in the framework of the broken‐symmetry approach using single‐ and double‐hybrid functionals as well as generalized‐gradient‐approximation (GGA) functionals. The computed magnetic exchange‐coupling constants are compared with experimental and other theoretical data, where available.
Sleep contributes to dendritic spine formation and elimination in the developing mouse somatosensory cortex
Authors: Yang Guang , Gan Wen‐Biao 
Published: November 2011

AbstractSleep is maximal during early postnatal life when rapid and extensive synapse remodeling occurs. It remains unknown whether and how sleep affects synapse development and plasticity. Using transcranial two‐photon microscopy, we examined the formation and elimination of fluorescently labeled dendritic spines and filopodia of Layer 5 pyramidal neurons in the barrel cortex of 3‐week‐old mice during wakefulness and sleep. We observed high turnover of dendritic protrusions over 2 h in both wake and sleep states. The formation rate of dendritic spines or filopodia over 2 h was comparable between the two states. The elimination rate of dendritic spines or filopodia was lower during 2‐h wakefulness than during 2‐h sleep. Similar results were observed on dendritic protrusion dynamics over 12‐h light/dark cycle when mice spent more time asleep or awake. The substantial remodeling of dendritic protrusions during the sleep state supports the notion that sleep plays an important role in the development and plasticity of synaptic connections in the mouse cortex. © 2011 Wiley Periodicals, Inc. Develop Neurobiol, 2012
Interconnected ordered nanoporous networks of colloidal crystals integrated on a microfluidic chip for highly efficient protein concentration
Authors: Hu Yu‐Lin , Wang Chen , Wu Zeng‐Qiang , Xu Jing‐Juan , Chen Hong‐Yuan , Xia Xing‐Hua 
Published: November 2011

AbstractWe report a controllable method to fabricate silica colloidal crystals at defined position in microchannel of microuidic devices using simple surface modification. The formed PCs (photonic crystals) in microfluidic channels were stabilized by chemical cross‐linking of Si‐O‐Si bond between neighboring silica beads. The voids among colloids in PCs integrated on microfluidic devices form interconnected nanoporous networks, which show special electroosmotic properties. Due to the “surface‐charge induced ion depletion effect” mechanism, FITC‐labeled proteins can be efficiently and selectively concentrated in the anodic boundary of the ion depletion zone. Using this device, about 103‐ to 105‐fold protein concentration was achieved within 10 min. The present simple on chip protein concentration device could be a potential sample preparation component in microfluidic systems for practical biochemical assays.
Effects of atopic dermatitis on the morphology and water content of scalp hair
Authors: Kim Kyung Sook , Shin Min Kyung , Kim Ji Hye , Kim Mi Hyun , Haw Choong‐Rim , Park Hun‐Kuk 
Published: November 2011

AbstractThe effects of atopic dermatitis (AD) on scalp hair properties, such as morphology and water content, were investigated using atomic force microscopy (AFM) and thermogravimetric analyzer. Hairs from lesional and nonlesional scalp regions of eight patients with AD were investigated. The severity of the disease, which was evaluated using the SCORing Atopic Dermatitis index, was 48.75 (range, 40–80). Hairs from 15 normal adults were also examined as controls. The surface images were taken in an area of 20 × 20 μm2 with 512 × 512 pixels and a scan speed of 0.8 line/s. AD affected the cuticle structures and scales of scalp hair. The edges of cuticles were torn and collapsed, and the scales were very thick. The water contents of both types of AD hair were less than the control: 12% ± 0.7%, 11.7% ± 0.4%, and 13% ± 0.8% for lesional AD hair, nonlesional AD hair, and control hair, respectively. The scalp hair of patients with AD can be characterized by thick and globular scale patterns. The hair of patients with AD has less water content than normal hair showing a good agreement with the property of skin having AD. Microsc. Res. Tech., 2012. © 2011 Wiley Periodicals, Inc.
Why is ENSO influencing Indian northeast monsoon in the recent decades?
Authors: Yadav R. K. 
Published: November 2011

AbstractThis study examines decadal changes of the El Niño/Southern Oscillation (ENSO) influence on the interannual variability (IAV) of Indian northeast monsoon rainfall (NEMR). In recent decades, the ENSO influence has strengthened over the NEMR variability. During El Niño years, the subsidence anomaly over the warm‐pool region of Indonesia was much stronger in the recent decades as compared to the earlier decades. The zonally elongated warm sea surface temperatures (SSTs) of the warm‐pool region along the tropical Indo‐Pacific Ocean were much warmer than the earlier decades, which had intensified the deep convections over the Indian Ocean. The northwestward propagating trailing Rossby‐gyres, formed in the western portion of the equatorial deep convection and stratiform heating, intensified as tropical storms and cyclones over north Indian Ocean. These storms and cyclones strike southern peninsular India and hence flood northeast monsoon (NEM) years. During the recent decades in the La Niña years, the contracted warm SSTs over the warm‐pool region were much warmer than the earlier decades which intensified the deep convection and stratiform heating over there. The tropical storms and cyclones that formed due to Rossby‐gyre dynamics had to travel a long distance towards the northwestward direction over the Bay of Bengal and misses southern peninsular India, and hence, the drought NEM years. Copyright © 2011 Royal Meteorological Society
Development of statistical models for at‐site probabilistic seasonal rainfall forecast
Authors: Villarini Gabriele , Serinaldi Francesco 
Published: November 2011

AbstractA probabilistic seasonal rainfall forecasting system for the Bucharest‐Filaret (Romania) station based on Generalized Additive Models in Location, Scale and Shape (GAMLSS) is proposed. First we develop statistical models to describe seasonal rainfall over the period 1926‐2000, both considering the seasonal record as a continuous time series and accounting for seasonal changes, and by developing ad hoc models for each individual season. The Southern Oscillation Index (SOI), the North Atlantic Oscillation (NAO) and the seasonal rainfall for the previous year are included as possible covariates. Model selection is performed with respect to two penalty criteria [Akaike Information Criterion (AIC) and Schwarz Bayesian Criterion (SBC)], each of them leading to different final model configurations in terms of predictors and their functional relation to the parameters of the probability distribution. Retrospective forecast, in which the parameters of the models are re‐estimated every time new information becomes available, is performed on a yearly basis for the period 1986‐2000. The quality of the forecasts is assessed in terms of several accuracy measures and by visual examination of the forecasts' probability distributions. The best forecasts are obtained for the winter season. While it is not possible to identify a single ‘best’ model according to all the forecast measures, we recommend using the model that considers the seasonal rainfall as a continuous time series and penalized with respect to AIC. Copyright © 2011 Royal Meteorological Society
Prognostic values of the miR‐17‐92 cluster and its paralogs in colon cancer
Authors: Yu Ge , Tang Jian‐qiang , Tian Mao‐lin , Li Hui , Wang Xin , Wu Tao , Zhu Jing , Huang Shan‐jun , Wan Yuan‐lian 
Published: November 2011

AbstractBackgroundMicroRNAs have been shown to offer great potential in both the diagnosis and prognosis of cancer. Despite the well‐established role of the miR‐17‐92 in cancer formation and progression, the contribution of each individual miRNA remains to be characterized. Thus, we investigated whether deregulation of the miR‐17‐92 associated with colon cancer prognosis.MethodsExpression levels of the miR‐17‐92 cluster and its paralogs were determined in 48 colon tumor and 48 paired normal tissues by real‐time qRT‐PCR. Associations with miRNA expression, age, sex, TNM staging, and survival prognosis were evaluated.ResultsMiR‐17‐92 cluster and its paralogs were significantly overexpressed in colon tumor. No significant associations were found between the deregulation of certain miRNAs and the clinical and pathologic characteristics observed in patients. Kaplan–Meier curves demonstrated significantly reduced overall survival in patients expressing high levels of miR‐17. In multivariate Cox models, miR‐17 overexpression (HR 2.67; P = 0.007) and TNM staging (HR 8.87; P = 0.002) were significantly associated with a risk of death.ConclusionsThe miR‐17‐92 cluster and its paralogs were significantly elevated in patients with colon cancer, and heightened expression of miR‐17 was associated with poor survival. Moreover, miR‐17 and TNM staging were both identified as significant, but independent, prognostic biomarkers in colon cancer. J. Surg. Oncol. 2012; 106:232–237. © 2011 Wiley Periodicals, Inc.
Effects of crop field characteristics on nocturnal winter use by American woodcock
Authors: Blackman Emily B. , Deperno Christopher S. , Heiniger Ron W. , Krachey Matthew J. , Moorman Christopher E. , Peterson M. Nils 
Published: November 2011

AbstractSince the late 1960s, American woodcock (Scolopax minor) have undergone population declines because of habitat loss. Previous research suggested ridge and furrow topography in conventionally tilled soybean fields provided critical nocturnal cover as birds foraged on earthworms. However, the use of no‐till technology has increased and many fields now lack ridge and furrow topography. We assessed woodcock winter nocturnal foraging habitat use given recent changes in agricultural technology, and investigated how field treatment, earthworm abundance, and environmental variables affect the selection of nocturnal foraging sites. We counted woodcock along transects in 5 field treatments twice in each of 67 fields during December–March 2008–2009 and 72 fields during December–March 2009–2010. During both seasons, we collected earthworm and soil samples from a subset of fields of each field treatment. Woodcock densities were at least twice as high in no‐till soybean fields planted after corn and in undisked corn fields with mowed stalks than in other field treatments. No‐till soybean planted after corn and undisked corn fields contained ridge and furrow topography, whereas other crops did not, and earthworms were at least 1.5 times more abundant in no‐till soybean fields than other field treatments. Ridges and furrows in no‐till soybean fields planted after corn and undisked corn fields may provide wintering woodcock with thermal protection and concealment from predators. No‐till soybean fields planted after corn offered the additional benefit of relatively high food availability. The presence of ridge and furrow topography can be used to predict woodcock field use on the wintering grounds in agricultural areas. Farmers can provide nocturnal winter foraging sites for woodcock by delaying field disking and leaving ridge and furrow topography in crop fields. © 2011 The Wildlife Society.
Time geography and wildlife home range delineation
Authors: Long Jed A. , Nelson Trisalyn A. 
Published: November 2011

AbstractWe introduce a new technique for delineating animal home ranges that is relatively simple and intuitive: the potential path area (PPA) home range. PPA home ranges are based on existing theory from time geography, where an animal's movement is constrained by known locations in space–time (i.e.,ntelemetry points) and a measure of mobility (e.g., maximum velocity). Using the formulation we provide, PPA home ranges can be easily implemented in a Geographic Information System (GIS). The advantage of the PPA home range is the explicit consideration of temporal limitations on animal movement. In discussion, we identify the PPA home range as a stand‐alone measure of animal home range or as a way to augment existing home range techniques. Future developments are highlighted in the context of the usefulness of time geography for wildlife movement analysis. To facilitate the adoption of this technique we provide a tool for implementing this method. © 2011 The Wildlife Society.
Potential for promoting recurrent laryngeal nerve regeneration by remote delivery of viral gene therapy
Authors: Rubin Adam D. , Hogikyan Norman D. , Oh Alex , Feldman Eva L. 
Published: November 2011

AbstractObjectives/Hypothesis:The aims of this study were to demonstrate the ability to enhance nerve regeneration by remote delivery of a viral vector to the crushed recurrent laryngeal nerve (RLN), to demonstrate the usefulness of a crushed RLN model to test the efficacy of viral gene therapy, and to discuss future potential applications of this approach.Study Design:Animal study.Methods:Adult Sprague‐Dawley rats were assigned to two groups. In the experimental group, an adeno‐associated viral (AAV) vector carrying a zinc‐finger transcription factor, which stimulates endogenous insulinlike growth factor I production (AAV2‐TO‐6876vp16), was injected into the crushed RLN. In the control group, an AAV vector carrying the gene for green fluorescent protein was injected into the crushed RLN. Unilateral RLN paralysis was confirmed endoscopically. At 1 week, laryngeal endoscopies were repeated and recorded. Larynges were cryosectioned in 15‐μm sections and processed for acetylcholine histochemistry (motor endplates) followed by neurofilament immunoperoxidase (nerve fibers). Percentage nerve‐endplate contact (PEC) was determined and compared. Vocal fold motion was evaluated by blinded reviewers using a visual analogue scale (VAS).Results:The difference between PEC on the crushed and uncrushed sides was statistically less in the experimental group (0.54 ± 0.18 vs. 0.30 ± 0.26, P = .0006). The VAS score at 1 week was significantly better in the experimental group (P = .002).Conclusions:AAV2‐TO‐6876vp16 demonstrated a neurotrophic effect when injected into the crushed RLN. The RLN offers a conduit for viral gene therapy to the brainstem that could be useful for the treatment of RLN injury or bulbar motor neuron disease.
The effect of continuous positive airway pressure on middle ear pressure
Authors: Lin Fred Y. , Gurgel Richard K. , Popelka Gerald R. , Capasso Robson 
Published: November 2011

AbstractObjectives/Hypothesis:While continuous positive airway pressure (CPAP) is commonly used for obstructive sleep apnea treatment, its effect on middle ear pressure is unknown. The purpose of this study was to measure the effect of CPAP on middle ear pressure and describe the correlation between CPAP levels and middle ear pressures.Study Design:Retrospective review of normal tympanometry values and a prospective cohort evaluation of subjects' tympanometric values while using CPAP at distinct pressure levels.Methods:A total of 3,066 tympanograms were evaluated to determine the normal range of middle ear pressures. Ten subjects with no known history of eustachian tube dysfunction or obstructive sleep apnea had standard tympanometry measurements while wearing a CPAP device. Measurements were taken at baseline and with CPAP air pressures of 0, 5, 10, and 15 cm H2O.Results:The percentage of normal control patients with middle ear pressures above 40 daPa was 0.03%. In the study population, prior to a swallowing maneuver to open the eustachian tube, average middle ear pressures were 21.67 daPa, 22.63 daPa, 20.42, daPa, and 21.58 daPa with CPAP pressures of 0, 5, 10, and 15 cm H20, respectively. After swallowing, average middle ear air pressures were 18.83 daPa, 46.75 daPa, 82.17 daPa, and 129.17 daPa with CPAP pressures of 0, 5, 10, and 15 cm H20, respectively. The postswallow Pearson correlation coefficient correlating CPAP and middle ear pressures was 0.783 (P < 0.001).Conclusions:Middle ear air pressure is directly proportional to CPAP air pressure in subjects with normal eustachian tube function. Middle ear pressure reaches supraphysiologic levels at even minimal CPAP levels. Although further investigation is necessary, there may be otologic implications for patients who are chronically CPAP dependent. These findings may also influence the perioperative practice of otologic and skull base surgeons.
Long‐term curcumin administration protects against atherosclerosis via hepatic regulation of lipoprotein cholesterol metabolism
Authors: Shin Su‐Kyung , Ha Tae‐Youl , McGregor Robin A. , Choi Myung‐Sook 
Published: November 2011

AbstractScope: Atherosclerosis is a major cause of cardiovascular disease caused by high cholesterol. Stains are widely prescribed to lower cholesterol levels, but natural dietary compounds may also be effective. Therefore, we studied the effect of the natural dietary compound curcumin on atherosclerosis and its underlying mechanisms based on plasma and hepatic lipid metabolism.Methods and results: LDLR−/− mice were fed a high‐cholesterol diet and treated with curcumin, lovastatin or control (n=10 per group) for 18 wk. Aortic arch sections revealed curcumin ameliorated early atherosclerotic lesions, lipid infiltration, ICAM‐1 and VCAM‐1 localization, similar to lovastatin treatment. Furthermore, curcumin lowered plasma cholesterol, triglycerides, LDL cholesterol and Apo B levels as well as CETP activity, while curcumin increased plasma HDL cholesterol and liver Apo A‐I expression, similar to lovastatin treatment. Curcumin caused transcriptional inhibition of HMG‐CoA reductase, independent of ACAT1 and ACAT2 expression. Hepatic PPARα and LXRα expression was upregulated by curcumin treatment. Hepatic complement factor D (Cfd) and systemic CRP levels, markers of immune complement pathway activation, were significantly reduced by curcumin treatment.Conclusion: Long‐term curcumin treatment lowers plasma and hepatic cholesterol and suppresses early atherosclerotic lesions comparable to the protective effects of lovastatin. The anti‐atherogenic effect of curcumin is mediated via multiple mechanisms including altered lipid, cholesterol and immune gene expression.
Keine Angst vor Paragraphen
Authors: Kraus Florian 
Published: November 2011

AbstractUnter welchen rechtlichen Voraussetzungen kann ein Chemiker mit Uran und Thorium experimentieren? Obwohl die Vielzahl der Gesetze und Verordnungen auf den ersten Blick einschüchternd erscheint, ist es gar nicht so kompliziert, mit natürlich vorkommenden radioaktiven Elementen chemisch zu arbeiten.
Bunsens Laboratorium
Authors: Nawa Christine 
Published: November 2011

AbstractAls Robert Bunsen im Jahr 1852 den Ruf an die Universität Heidelberg annahm, sicherte die badische Landesregierung ihm den Neubau eines chemischen Laboratoriums zu. Im Sommersemester 1855 eröffnet, galt es als das modernste und am besten ausgestattete in ganz Europa.
On the numerical stability and mass‐lumping schemes for explicit enriched meshfree methods
Authors: Talebi Hossein , Samaniego Cristóbal , Samaniego Esteban , Rabczuk Timon 
Published: November 2011

SUMMARYMeshfree methods (MMs) such as the element free Galerkin (EFG)method have gained popularity because of some advantages over other numerical methods such as the finite element method (FEM). A group of problems that have attracted a great deal of attention from the EFG method community includes the treatment of large deformations and dealing with strong discontinuities such as cracks. One efficient solution to model cracks is adding special enrichment functions to the standard shape functions such as extended FEM, within the FEM context, and the cracking particles method, based on EFG method.It is well known that explicit time integration in dynamic applications is conditionally stable. Furthermore, in enriched methods, the critical time step may tend to very small values leading to computationally expensive simulations. In this work, we study the stability of enriched MMs and propose two mass‐lumping strategies. Then we show that the critical time step for enriched MMs based on lumped mass matrices is of the same order as the critical time step of MMs without enrichment. Moreover, we show that, in contrast to extended FEM, even with a consistent mass matrix, the critical time step does not vanish even when the crack directly crosses a node. Copyright © 2011 John Wiley & Sons, Ltd.