bluuebunny/crossref_metadata_2025 huggingface dataset:
Peptaibol Antiamoebin I: Spatial Structure, Backbone Dynamics, Interaction with Bicelles and Lipid‐Protein Nanodiscs, and Pore Formation in Context of Barrel‐Stave Model
Authors: Shenkarev Zakhar O. , Paramonov Alexander S. , Lyukmanova Ekaterina N. , Gizatullina Albina K. , Zhuravleva Anastasia V. , Tagaev Andrey A. , Yakimenko Zoya A. , Telezhinskaya Irina N. , Kirpichnikov Mikhail P. , Ovchinnikova Tatiana V. , Arseniev Alexander S.
Published: May 2013

Antiamoebin I (Aam‐I) is a membrane‐active peptaibol antibiotic isolated from fungal species belonging to the genera Cephalosporium, Emericellopsis, Gliocladium, and Stilbella. In comparison with other 16‐amino acid‐residue peptaibols, e.g., zervamicin IIB (Zrv‐IIB), Aam‐I possesses relatively weak biological and channel‐forming activities. In MeOH solution, Aam‐I demonstrates fast cooperative transitions between right‐handed and left‐handed helical conformation of the N‐terminal (1–8) region. We studied Aam‐I spatial structure and backbone dynamics in the membrane‐mimicking environment (DMPC/DHPC bicelles)1) by heteronuclear 1H,13C,15N‐NMR spectroscopy. Interaction with the bicelles stabilizes the Aam‐I right‐handed helical conformation retaining significant intramolecular mobility on the ms–μs time scale. Extensive ms–μs dynamics were also detected in the DPC and DHPC micelles and DOPG nanodiscs. In contrast, Zrv‐IIB in the DPC micelles demonstrates appreciably lesser mobility on the μs–ms time scale. Titration with Mn2+ and 16‐doxylstearate paramagnetic probes revealed Aam‐I binding to the bicelle surface with the N‐terminus slightly immersed into hydrocarbon region. Fluctuations of the Aam‐I helix between surface‐bound and transmembrane (TM) state were observed in the nanodisc membranes formed from the short‐chain (diC12 : 0) DLPC/DLPG lipids. All the obtained experimental data are in agreement with the barrel‐stave model of TM pore formation, similarly to the mechanism proposed for Zrv‐IIB and other peptaibols. The observed extensive intramolecular dynamics explains the relatively low activity of Aam‐I.
Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control
Authors: Doll Theodor , Velasco‐Velez Juan J. , Rosenthal Dirk , Avila Jonathan , Fuenzalida Victor
Published: May 2013

Microchemical sensors and catalytic reactors make use of gases during adsorption in specific ways on selected materials. Fine‐tuning is normally achieved by morphological control and material doping. The latter relates surface properties to the electronic structure of the bulk, and this suggests the possibility of electronic control. Although unusual for catalytic surfaces, such phenomena are sometimes reported for microsensors, but with little understanding of the underlying mechanisms. Herein, direct observation of the electroadsorptive effect by a combination of X‐ray photoelectron spectroscopy and conductivity analysis on nanometre‐thick semiconductor films on buried control electrodes is reported. For the SnO2/NO2 model system, NO3 surface species, which normally decay at the latest within minutes, can be kept stable for 1.5 h with a high coverage of 15 % under appropriate electric fields. This includes uncharged states, too, and implies that nanoelectronic structures provide control over the predominant adsorbate conformation on exterior surfaces and thus opens the field for chemically reactive interfaces with in situ tunability.
Controlled Hydrophobic Functionalization of Natural Fibers through Self‐Assembly of Amphiphilic Diblock Copolymer Micelles
Authors: Aarne Niko , Laine Janne , Hänninen Tuomas , Rantanen Ville , Seitsonen Jani , Ruokolainen Janne , Kontturi Eero
Published: May 2013

The functionalization of natural fibers is an important task that has recently received considerable attention. We investigated the formation of a hydrophobic layer from amphiphilic diblock copolymer micelles [polystyrene‐block‐poly(N‐methyl‐4‐vinyl pyridinium iodide)] on natural fibers and on a model surface (mica). A series of micelles were prepared. The micelles were characterized by using cryoscopic TEM and light scattering, and their hydrophobization capability was studied through contact angle measurements, water adsorption, and Raman imaging. Mild heat treatment (130 °C) was used to increase the hydrophobization capability of the micelles. The results showed that the micelles could not hydrophobize a model surface, but could render the natural fibers water repellent both with and without heat treatment. This effect was systematically studied by varying the composition of the constituent blocks. The results showed that the micelle size (and the molecular weight of the constituent diblock copolymers) was the most important parameter, whereas the cationic (hydrophilic) part played only a minor role. We hypothesized that the hydrophobization effect could be attributed to a combination of the micelle size and the shrinkage of the natural fibers upon drying. The shrinking caused the roughness to increase on the fiber surface, which resulted in a rearrangement of the self‐ assembled layer in the wet state. Consequently, the fibers became hydrophobic through the roughness effects at multiple length scales. Mild heat treatment melted the micelle core and decreased the minimum size necessary for hydrophobization.
Modeling of dipole–dipole‐coupled, electric field‐driven, protein‐based computing architectures
Authors: Rakos Balázs
Published: May 2013

In the present study, we propose a novel approach for the realization of protein‐based logic circuits potentially suitable for nanoscale digital signal processing and computing architectures. Electric field‐induced switching of Dronpa, an artificial protein, is demonstrated through simulations with the NAMD molecular dynamics simulation software, and a circuit model that describes such switching behavior is presented. Simulations suggest that digital signal propagation and the majority gate can be realized by the utilization of such proteins if they are dipole–dipole coupled and are driven by proper electric fields. Copyright © 2013 John Wiley & Sons, Ltd.
Subtyping of nonsmall cell lung cancer on cytology specimens: Reproducibility of cytopathologic diagnoses on sparse material
Authors: Omland Silje Haukali , Henrik Hager , Olsen Ege Karen , Birthe Thomsen , Guldhammer Skov Birgit
Published: May 2013

Cytologic examination of fine‐needle aspiration (material is increasingly used in diagnosing lung cancer. High interobserver agreement in distinguishing small‐cell lung cancer from nonsmall‐cell lung cancer (NSCLC) on cytologic material has been demonstrated. Because of new treatment‐modalities, subclassification of NSCLC into squamous cell carcinoma (SQC) and non‐SQC has clinical impact. Subclassification based on morphology alone may be difficult, but applying immunohistochemistry (IHC) to clot‐material has proved helpful. When insufficient material is available to make a clot from the aspirate, cytoscrape (CS) can convert cytologic material into tissue fragments useful for IHC. The purpose of this study was to test the reproducibility of pulmonary malignant diagnoses, in particular distinction between subgroups of NSCLC, based on smeared material and IHC on CS. A consecutive series of May–Grunwald–Giemsa (MGG) stained smears and CS with IHC on material from 79 patients suspected of having lung cancer was included. The material was circulated twice to four pathologists. The diagnoses were categorized in five groups: SQC, adenocarcinoma of the lung, non‐SQC, benign lesion and other forms of malignancy, including metastases. Reproducibility was analyzed using Kappa statistics. Interobserver reproducibility of the diagnoses in round 1 was good to very good (kappa 0.57–0.71) and very good in round 2 (0.63–0.80). Reproducibility of subclassification of NSCLC based on MGG stained smear and IHC on CS, was very good among experienced pathologists. With only sparse material available, CS should be used to achieve reproducible diagnoses, including subtyping of NSCLC. Diagn. Cytopathol. 2014;42: 105–110. © 2013 Wiley Periodicals, Inc.
Antimicrobials for non‐typhoidal Salmonella infection—does it work?
Authors: Robinson Joan
Published: May 2013

Eco‐paediatrics is an occasional feature in Evidence‐Based Child Health: A Cochrane Review Journal. Our goal is to contribute to the worldwide discussion on reducing waste in health care. In each instalment, we will select a recent Cochrane review highlighting a practice, still in use, which the available evidence tells us should be discontinued.
Commentaries on ‘Remediating buildings damaged by dampness and mould for preventing or reducing respiratory tract symptoms, infections and asthma’
Authors: Liira Helena , Kovesi Thomas
Published: May 2013

These are commentaries on a Cochrane review, published in the issue of EBCH, first published as: Sauni R, Uitti J, Jauhiainen M, Kreiss K, Sigsgaard T, Verbeek JH. Remediating buildings damaged by dampness and mould for preventing or reducing respiratory tract symptoms, infections and asthma. Cochrane Database of Systematic Reviews 2011, Issue 9. Art. No.: CD007897. DOI: 10.1002/14651858.CD007897.pub2.
A Facile Synthesis of 4,6,7,8,8a,9‐Hexahydropyrrolo[1,2‐a][1,2,3]triazolo[1,5‐d]pyr­azines by a Three‐Component Coupling Reaction Followed by Intramolecular 1,3‐Dipolar Cycloaddition
Authors: Dhondge Attrimuni P. , Afraj Shakil N. , Nuzlia Cut , Chen Chinpiao , Lee Gene‐Hsian
Published: May 2013

A practical and efficient two‐step protocol for the synthesis of several new 4,6,7,8,8a,9‐hexahydropyrrolo[1,2‐a][1,2,3]triazolo[1,5‐d]pyrazines is described. The first step involves the AuBr3‐catalyzed three‐component coupling reaction of terminal alkynes, aldehydes, and amines under solvent‐free conditions to provide the requisite propargylamines. The reaction tolerates a high structural diversity, requires only short reaction times, gives high diastereoselectivities, and is environmentally benign. Furthermore, the propargylamine products undergo catalyst‐free intramolecular azide–alkyne [3 + 2] dipolar cycloaddition reactions to give the 4,6,7,8,8a,9‐hexahydropyrrolo[1,2‐a][1,2,3]triazolo[1,5‐d]pyrazines in excellent yields and with excellent diastereoselectivities.
New adaptive frame aggregation call admission control (AFA‐CAC) for high throughput WLANs
Authors: Charfi Emna , Chaari Lamia , Kamoun Lotfi
Published: May 2013

The major enhancements introduced by the very high throughput wireless local area network, cannot provide quality of service (QoS) satisfaction for real time and multimedia applications. The recent standard IEEE 802.11n introduced new Medium Access Control (MAC) mechanisms based on aggregation scheme to enhance throughput. Besides that, functional modules for QoS provisioning such as call admission control and bandwidth management should be implemented in the access point. Hence, an efficient call admission control (CAC) algorithm is required for 802.11n network to satisfy QoS requirements of strict multimedia services. In this paper, we propose a new model‐based call admission control algorithm, called adaptation of frame aggregation AFA‐CAC to be implemented within the QoS access point in IEEE 802.11n standard in a way to provide QoS satisfaction to real time services. We first propose an accurate analytical model to estimate the achieved QoS metrics of a new flow entering in the network. Then, we detailed the AFA‐CAC algorithm that supports IEEE 802.11n aggregation schemes aggregated MAC service data unit and aggregated MAC protocol data unit and consider the IEEE 802.11e enhanced distributed channel access. AFA‐CAC is based on both predicting the QoS constraints of the already active flows and the new flow, and adjusting the number of aggregated subframes of each flow. Conducted simulations illustrate the performance of our proposed AFA‐CAC in terms of satisfying QoS throughput and end‐to‐end delay requirements of voice and video traffics. Copyright © 2013 John Wiley & Sons, Ltd.
Vascular risk factors and neuropsychiatric symptoms in Alzheimer's disease: the Cache County Study
Authors: Steinberg Martin , Hess Kyle , Corcoran Chris , Mielke Michelle M. , Norton Maria , Breitner John , Green Robert , Leoutsakos Jeannie , Welsh‐Bohmer Kathleen , Lyketsos Constantine , Tschanz Joann
Published: May 2013

Objective

Knowledge of potentially modifiable risk factors for neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) is important. This study longitudinally explores modifiable vascular risk factors for NPS in AD.

Methods

Participants enrolled in the Cache County Study on Memory in Aging with no dementia at baseline were subsequently assessed over three additional waves, and those with incident (new onset) dementia were invited to join the Dementia Progression Study for longitudinal follow‐up. A total of 327 participants with incident AD were identified and assessed for the following vascular factors: atrial fibrillation, hypertension, diabetes mellitus, angina, coronary artery bypass surgery, myocardial infarction, cerebrovascular accident, and use of antihypertensive or diabetes medicines. A vascular index (VI) was also calculated. NPS were assessed over time using the Neuropsychiatric Inventory (NPI). Affective and Psychotic symptom clusters were assessed separately. The association between vascular factors and change in NPI total score was analyzed using linear mixed model and in symptom clusters using a random effects model.

Results

No individual vascular risk factors or the VI significantly predicted change in any individual NPS. The use of antihypertensive medications more than four times per week was associated with higher total NPI and Affective cluster scores.

Conclusions

Use of antihypertensive medication was associated with higher total NPI and Affective cluster scores. The results of this study do not otherwise support vascular risk factors as modifiers of longitudinal change in NPS in AD. Copyright © 2013 John Wiley & Sons, Ltd.
The receptor TGR5 protects the liver from bile acid overload during liver regeneration in mice
Authors: Péan Noémie , Doignon Isabelle , Garcin Isabelle , Besnard Aurore , Julien Boris , Liu Bingkaï , Branchereau Sophie , Spraul Anne , Guettier Catherine , Humbert Lydie , Schoonjans Kristina , Rainteau Dominique , Tordjmann Thierry
Published: May 2013

Many regulatory pathways are involved in liver regeneration after partial hepatectomy (PH) to initiate growth, protect liver cells, and sustain functions of the remnant liver. Bile acids (BAs), whose levels rise in the blood early after PH, stimulate both hepatocyte proliferation and protection, in part through their binding to the nuclear farnesoid X receptor (FXR). However, the effect of the BA receptor, TGR5 (G-protein-coupled BA receptor 1) after PH remains to be studied. Liver histology, hepatocyte proliferation, BA concentrations (plasma, bile, liver, urine, and feces), bile flow and composition, and cytokine production were studied in wild-type (WT) and TGR5 KO (knockout) mice before and after PH. BA composition (plasma, bile, liver, urine, and feces) was more hydrophobic in TGR5 KO than in WT mice. After PH, severe hepatocyte necrosis, prolonged cholestasis, exacerbated inflammatory response, and delayed regeneration were observed in TGR5 KO mice. Although hepatocyte adaptive response to post-PH BA overload was similar in WT and TGR5 KO mice, kidney and biliary adaptive responses were strongly impaired in TGR5 KO mice. Cholestyramine treatment, as well as Kupffer cell depletion, significantly improved the post-PH TGR5 KO mice phenotype. After bile duct ligation or upon a cholic acid–enriched diet, TGR5 KO mice exhibited more severe liver injury than WT as well as impaired BA elimination in urine.

Conclusion

: TGR5 is crucial for liver protection against BA overload after PH, primarily through the control of bile hydrophobicity and cytokine secretion. In the absence of TGR5, intrahepatic stasis of abnormally hydrophobic bile and excessive inflammation, in association with impaired bile flow adaptation and deficient urinary BA efflux, lead to BA overload-induced liver injury and delayed regeneration. (Hepatology 2013;58:1451–1460)
Therapeutic advantage of anti-VAP-1 over anti-α4 integrin antibody in concanavalin a-induced hepatitis
Authors: Lee Woo-Yong , Salmi Marko , Kelly Margaret M. , Jalkanen Sirpa , Kubes Paul
Published: May 2013

Hepatitis induced by concanavalin A (Con A) in mice is well known to be a T-lymphocyte-mediated injury. It has been reported that T helper (Th)1 and Th2 lymphocytes use α4 integrin and vascular adhesion protein (VAP)−1, respectively, to adhere within the hepatic sinusoids. Therefore, we investigated whether inhibition of these molecules ameliorates or worsens the Con A-induced hepatic injury

in vivo

. Vehicle or antibody to α4 integrin or VAP-1 was intravenously administered 30 minutes before Con A administration. In control mice Con A markedly increased the serum alanine aminotransferase (ALT) level in a dose-dependent manner, and induced a massive infiltration of CD3, particularly interleukin (IL)−4 producing CD4 T cells and liver injury. Both parameters were reduced by anti-VAP-1 antibody despite antibody only blocking the adhesion, not the amine oxidase activity of VAP-1. Both activities of VAP-1 were eliminated in VAP-1-deficient mice and both Con A-induced liver injury and CD4 T-cell infiltration were eradicated. In contrast to anti-VAP-1, anti-α4 integrin antibody reduced interferon-gamma (IFN-γ)-producing CD3 T cells but this worsened Con A hepatitis, suggesting inhibition of a suppressor cell. Con A induced the recruitment of CD49d+ monocytic myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) into the liver. Anti-α4 integrin dramatically blocked the influx of MDSCs but not Tregs.

Conclusion

: Our findings show that VAP-1 and α4 integrin have opposing effects in Con A-induced hepatic injury, which is associated with blocking the recruitment of CD4 lymphocytes and monocytic MDSCs, respectively. Moreover, these data provide the rationale for a potential therapeutic approach to target adhesion molecules in autoimmune hepatitis. (Hepatology 2013;58:1413–1423)
Benzo‐Annulated Steroids: Synthesis of Octahydro‐indeno‐phenanthrenes by Formal [3+3] Cyclocondensation Reaction with 1,3‐Bis[(trimethylsilyl)oxy]buta‐1,3‐dienes
Authors: Erben Friedrich , Specowius Verena , Wölfling János , Schneider Gyula , Langer Peter
Published: May 2013

Octahydro‐indeno‐phenanthrenes, benzo‐annulated steroids, were prepared by formal [3+3] cyclocondensation reaction of 1,3‐bis[(trimethylsilyl)oxy]buta‐1,3‐dienes with the silyl enol ether of 16‐formylestrone methyl ether.
Five New Steroidal Alkaloid Glycosides from Solanum tuberosum
Authors: Zhang Zhi‐Qiang , Luo Jian‐Guang , Wang Jun‐Song , Kong Ling‐Yi
Published: May 2013

Five new steroidal alkaloid glycosides, 1–5, along with the known analog 6, have been isolated from the aerial parts of Solanum tuberosum. The structures of the new compounds were elucidated by spectroscopic methods, including 1D‐ and 2D‐NMR and HR‐ESI‐MS techniques, as well as by comparison of the spectral data with those of related compounds. Only compound 6 showed significant cytotoxicity.
Scope and Limitations of the Base‐Free Copper(I) Oxide Catalyzed N‐Heteroarylation of 1H‐(Benz)imidazoles with B‐Heteroarylboronic Acids or 2‐Heteroaryl‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolanes
Authors: Begouin Agathe , Queiroz Maria‐João R. P.
Published: May 2013

The known, very efficient base‐free copper(I) oxide catalyzed N‐arylation reaction performed in MeOH at room temperature for the synthesis of N‐substituted azoles and amines was extended to the heterocyclic series, i.e., we report herein the base‐free copper(I) oxide catalyzed N‐heteroarylation of 1H‐(benz)imidazole, by means of electron‐rich or electron‐deficient B‐heteroarylboronic acids or 2‐heteroaryl‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolanes (Schemes 1 and 2). Under these conditions, N‐heteroarylated 1H‐(benz)imidazoles were obtained in good to excellent yields (Tables 1 and 2). This is the first time that 2‐heteroaryl‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolanes were used in this type of reaction.
Stereoselective Synthesis of (−)‐Pinidinone
Authors: Shankaraiah Gundeti , Vijaya Kumar Tiruvayamudi , Venkateswara Reddy Guvvala , Madhusudana Rao Janaswamy , Suresh Babu Katragadda
Published: May 2013

A simple and efficient stereoselective linear approach to the total synthesis of (−)‐pinidinone has been accomplished starting from propane‐1,3‐diol, and employing Maruoka asymmetric allylation and Grubbs' olefin cross‐metathesis as the key steps.
Synthesis of Thymidine, Uridine, and 5‐Methyluridine Nucleolipids: Tools for a Tuned Lipophilization of Oligonucleotides
Authors: Werz Emma , Viere Rebecca , Gassmann Gina , Korneev Sergei , Malecki Edith , Rosemeyer Helmut
Published: May 2013

Three pyrimidine nucleosides, uridine (1), 5‐methyluridine (6), and 2′‐deoxythymidine (11), were converted to amphiphilic nucleolipids. Compounds 1 and 6 were lipophilized by introduction of symmetric ketal moieties with various carbon chain lengths (i.e., 5–17). Two ketal derivatives, 2b and 7a, were additionally further hydrophobized by N(3)‐farnesylation. 2′‐Deoxythymidine was alkylated at N(3) with a cetyl (=hexadecyl) residue, either directly or, after complete orthogonal protection of the sugar OH groups, by Mitsunobu reaction with hexadecan‐1‐ol. Some of the nucleolipids were subsequently converted to their 2‐cyanoethyl phosphoramidites (5′ or 3′), one of which was used for an exemplary synthesis of a lipo‐oligonucleotide. The sequence of this lipo‐oligonucleotide is an encoded manifestation of Pythagoras' law, created with a key table in which the letters of the alphabet, the numbers from 0 to 9 as well as the mostly used mathematical symbols are allocated to a ribonucleic acid triplet of the genetic code.
Stoichiometric Reactions of Enamines Derived from Diphenylprolinol Silyl Ethers with Nitro Olefins and Lessons for the Corresponding Organocatalytic Conversions – a Survey
Authors: Seebach Dieter , Sun Xiaoyu , Ebert Marc‐Olivier , Schweizer W. Bernd , Purkayastha Nirupam , Beck Albert K. , Duschmalé Jörg , Wennemers Helma , Mukaiyama Takasuke , Benohoud Meryem , Hayashi Yujiro , Reiher Markus
Published: May 2013

The stoichiometric reactions of enamines prepared from aldehydes and diphenyl‐prolinol silyl ethers (intermediates of numerous organocatalytic processes) with nitro olefins have been investigated. As reported in the last century for simple achiral and chiral enamines, the products are cyclobutanes (4 with monosubstituted nitro‐ethenes), dihydro‐oxazine N‐oxide derivatives (5 with disubstituted nitro‐ethenes), and nitro enamines derived from γ‐nitro aldehydes (6, often formed after longer reaction times). The same types of products were shown to be formed, when the reactions were carried out with peptides H‐Pro‐Pro‐Xaa‐OMe that lack an acidic H‐atom. Functionalized components such as alkoxy enamines, nitro‐acrylates, acetamido‐nitro‐ethylene, or hydroxylated nitro olefins also form products carrying the diphenyl‐prolinol silyl ether as a substituent. All of these products must be considered intermediates in the corresponding catalytic reactions; the investigation of their chemical properties provided useful hints about the rates, the conditions, the catalyst resting states or irreversible traps, and/or the limitations of the corresponding organocatalytic processes. High‐level DFT and MP2 computations of the structures of alkoxy enamines and thermodynamic data of a cyclobutane dissociation are also described. Some results obtained with the stoichiometrically prepared intermediates are not compatible with previous mechanistic proposals and assumptions.
Discussion about the validity of sharp‐interface models to deal with seawater intrusion in coastal aquifers
Authors: Llopis‐Albert Carlos , Pulido‐Velazquez David
Published: May 2013

Analytical models have been exhaustively used to study simple seawater intrusion problems and the sustainable management of groundwater resources in coastal aquifers because of its simplicity, easy implementation, and low computational cost. Most of these models are based on the sharp‐interface approximation and the Ghyben–Herzberg relation, and their governing equations are expressed in terms of a single potential theory to calculate critical pumping rates in a coastal pumping scenario. The Ghyben–Herzberg approach neglects mixing of fresh water and seawater and implicitly assumes that salt water remains static. Therefore, the results of the analytical solutions may be inaccurate and unacceptable for some real‐complex case studies. This paper provides insight into the validity of sharp‐interface models to deal with seawater intrusion in coastal aquifers, i.e. when they can be applied to obtain accurate enough results. For that purpose, this work compares sharp‐interface solutions, based on the Ghyben–Herzberg approach, with numerical three‐dimensional variable‐density flow simulations for a set of heterogeneous groundwater flow and mass transport parameters, and different scenarios of spatially distributed recharge values and spatial wells placement. The numerical experiment has been carried out in a 3D unconfined synthetic aquifer using the finite difference numerical code SEAWAT for solving the coupled partial differential equations of flow and density‐dependent transport. This paper finds under which situations the sharp‐interface solution gives good predictions in terms of seawater penetration, transition zone width and critical pumping rates. Additionally, the simulation runs indicate to which parameters and scenarios the results are more sensitive. Copyright © 2013 John Wiley & Sons, Ltd.
Modelling how vegetation cover affects climate change impacts on streamflow timing and magnitude in the snowmelt‐dominated upper Tuolumne Basin, Sierra Nevada
Authors: Cristea Nicoleta C. , Lundquist Jessica D. , Loheide Steven P. , Lowry Christopher S. , Moore Courtney E.
Published: May 2013

We investigated, through hydrologic modelling, the impact of the extent and density of canopy cover on streamflow timing and on the magnitude of peak and late summer flows in the upper Tuolumne basin (2600–4000 m) of the Sierra Nevada, California, under current and warmer temperatures. We used the Distributed Hydrology Soil Vegetation Model for the hydrologic modelling of the basin, assuming four vegetation scenarios: current forest (partial cover, 80% density), all forest (uniform coverage, 80% density), all barren (no forest) and thinned forest (partial cover, 40% density) for a medium‐high emissions scenario causing a 3.9 °C warming over a 100‐year period (2001–2100). Significant advances in streamflow timing, quantified as the centre of mass (COM) of over 1 month were projected for all vegetation scenarios. However, the COM advances faster with increased forest coverage. For example, when forest covered the entire area, the COM occurred on average 12 days earlier compared with the current forest coverage, with the rate of advance higher by about 0.06 days year−1 over 100 years and with peak and late summer flows lower by about 20% and 27%, respectively. Examination of modelled changes in energy balance components at forested and barren sites as temperatures rise indicated that increases in net longwave radiation are higher in the forest case and have a higher contribution to melting earlier in the calendar year when shortwave radiation is a smaller fraction of the energy budget. These increases contributed to increased midwinter melt under the forest at temperatures above freezing, causing decreases in total accumulation and higher winter and early spring melt rates. These results highlight the importance of carefully considering the combined impacts of changing forest cover and climate on downstream water supply and mountain ecosystems. Copyright © 2013 John Wiley & Sons, Ltd.
Modelling potential effects of climate change on winter turbidity loading in the Ashokan Reservoir, NY
Authors: Samal Nihar R. , Matonse Adao. H. , Mukundan Rajith , Zion Mark S. , Pierson Donald C. , Gelda Rakesh K. , Schneiderman Elliot M.
Published: May 2013

Recent studies have indicated that potential future climate change may lead to changes in the timing and quantity of snowpack accumulation and winter (November to April) streamflow patterns including increased streamflow and turbidity in early winter and a slight reduction in turbidity loads at the time of traditional early spring run‐off. In this study, we examine the potential effects of these predicted changes on reservoir turbidity levels. Our analysis focuses on Ashokan Reservoir, NY, which can at times receive significant watershed turbidity inputs mainly from stream channel erosion from the Esopus Creek. Both measured and simulated turbidity loads and climatology are input to CE‐QUAL‐W2 (W2), a reservoir turbidity transport model that can simulate reservoir turbidity and other water quality parameters. The W2 model is applied to estimate the effects of hydroclimatology on effective settling rates and turbidity transport as a result of differences in reservoir thermal structure during summer and winter events. Simulations suggest that the effective settling velocity is substantially lower at low temperatures during winter time. Winter average stream flow is simulated to increase by 12% and 20%, which leads to increases in reservoir turbidity by 11% and 17% for the future period 2046–2065 and 2081–2100, respectively. From a seasonal perspective, a change in timing of peak streamflow with increased flows during the winter and slightly reduced flows during early spring leads to increased average reservoir turbidity during winter and slightly decreased in‐reservoir turbidity during early spring and summer. Copyright © 2013 John Wiley & Sons, Ltd.
On the Origin of the Canonical Nucleobases: An Assessment of Selection Pressures across Chemical and Early Biological Evolution
Authors: Rios Andro C. , Tor Yitzhak
Published: May 2013

The native bases of RNA and DNA are prominent examples of the narrow selection of organic molecules upon which life is based. How did nature “decide” upon these specific heterocycles? Evidence suggests that many types of heterocycles could have been present on the early Earth. It is therefore likely that the contemporary composition of nucleobases is a result of multiple selection pressures that operated during early chemical and biological evolution. The persistence of the fittest heterocycles in the prebiotic environment towards, for example, hydrolytic and photochemical assaults, may have given some nucleobases a selective advantage for incorporation into the first informational polymers. The prebiotic formation of polymeric nucleic acids employing the native bases remains, however, a challenging problem to reconcile. Hypotheses have proposed that the emerging RNA world may have included many types of nucleobases. This is supported by the extensive utilization of non‐canonical nucleobases in extant RNA and the resemblance of many of the modified bases to heterocycles generated in simulated prebiotic chemistry experiments. Selection pressures in the RNA world could have therefore narrowed the composition of the nucleic acid bases. Two such selection pressures may have been related to genetic fidelity and duplex stability. Considering these possible selection criteria, the native bases along with other related heterocycles seem to exhibit a certain level of fitness. We end by discussing the strength of the N‐glycosidic bond as a potential fitness parameter in the early DNA world, which may have played a part in the refinement of the alphabetic bases.
Institutional Research in Light of Internationalization, Growth, and Competition
Authors: Taylor Barrett J. , Webber Karen L. , Jacobs Gerrie J.
Published: May 2013

Globalization, growth, and competition are challenges faced by many postsecondary institutions across the world. Institutional researchers have a prominent role to play in examining the issues related to these challenges and alerting campus leaders to the impact they may have on the institution and higher education in general.
Institutional Research in Emerging Countries of Southern Africa, Latin America, and the Middle East and North Africa: Global Frameworks and Local Practices
Authors: Lange Lis , Saavedra F. Mauricio , Romano Jeanine
Published: May 2013

This chapter presents a synthesis of the conceptualization and practice of institutional research (IR) in higher education (HE) in emerging countries across Southern Africa, Latin America and the Middle East and North Africa (MENA) regions. The chapter contextualizes the growing need for IR in these regions, identifies problems and challenges related to the implementation of IR at system and institutional levels, and offers some reflections about the future of IR in these regions. The chapter argues that the homogenizing effect of globalization makes IR practices very much alike across regions.
Challenges in Developing Data Collection Systems in a Rapidly Evolving Higher Education Environment
Authors: Borden Victor M. H. , Calderon Angel , Fourie Neels , Lepori Benedetto , Bonaccorsi Andrea
Published: May 2013

Efforts to develop common higher education data standards are expanding both within and across countries. The institutional research (IR) community plays a critical role in assuring that these efforts capture the diverse manifestations of the postsecondary and tertiary education systems and promote responsible comparisons.
The need for stent–lesion matching to optimize outcomes of intracoronary stent implantation
Authors: Lanzer Peter , Strupp Gerhard , Schmidt Wolfram , Topoleski L. D. Timmie
Published: May 2013

Intracoronary stents have markedly improved the outcomes of catheter‐based coronary interventions. Intracoronary stent implantation rates of over 90% during coronary angioplasty are common. Stent implantations are associated with a small but statistically significant number of adverse outcomes including restenosis, thrombosis, strut malapposition, incomplete strut endothelialization, and various types of stenting failure. Better matching of biomechanical properties of stents and lesions could further improve the clinical outcome of intracoronary stenting. Thus, in this article, we assess the need for advanced intracoronary stent–lesion matching. We reviewed the data on biomechanics of coronary stents and lesions to develop knowledge‐based rationale for optimum intracoronary stent selection. The available technical information on marketed intracoronary stents and the current understanding of the biomechanical properties of coronary lesions at rest and under stress are limited, preventing the development of knowledge‐based rationale for optimum intracoronary stent selection at present. Development of knowledge‐based selection of intracoronary stents requires standardization of mechanical stent testing, communication of the nonproprietary technical data on stents by the industry and dedicated research into procedural stent–lesion interactions. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1560–1570, 2013.
Higher doses of CD34+ progenitors are associated with improved overall survival without increasing GVHD in reduced intensity conditioning allogeneic transplant recipients with clinically advanced disease
Authors: Gómez‐Almaguer David , Gómez‐Peña Álvaro , Jaime‐Pérez José Carlos , Gómez‐Guijosa Miguel Ángel , Cantú‐Rodríguez Olga , Gutiérrez‐Aguirre Homero , Martínez‐Cabriales Sylvia Aidé , García‐Rodríguez Fernando , Olguín‐Ramírez Leticia A. , Salazar‐Riojas Rosario , Méndez‐Ramírez Nereida
Published: May 2013

Objective

The influence of CD34+ cell dose on the outcome of allogeneic peripheral blood stem cell (PBSC) transplantation after reduced intensity conditioning (RIC) remains controversial. The impact of the number of CD34+ hematoprogenitors infused on transplant outcome and on the incidence of graft versus host disease (GVHD) was analyzed.

Materials and methods

Data of 138 patients with advanced hematological diseases who received an allogeneic PBSC transplant after RIC were analyzed. Donors were mobilized with granulocyte colony‐stimulating factor and underwent one to three apheresis procedures. Incidence of acute and chronic GVHD and overall and event‐free survival (OS and EFS) was determined.

Results

The median number of CD34+ cells infused was 5.57 × 106 kg−1 (range: 1.1–15.6). There was no relationship between CD34+ cell dose and neutrophil or platelet engraftment. Patients receiving ≥5 × 106 kg−1 CD34+ cells had a 63.1% 5‐year OS when compared with 48.2% for those receiving a lower number (P = 0.024). At 5‐year follow‐up, there was no significant difference in EFS between the groups (44% vs. 42.8%, P = 0.426). No relationship between CD34+ cell dose and acute GVHD was found (P = 0.1). Relapse rate was the same in patients with and without acute GVHD (P = 0.117). A nonsignificant improvement on OS and EFS in patients who developed chronic GVHD was found (P = 0.57 and 0.41).

Conclusion

A CD34+ cell dose ≥5 × 106 kg−1 was associated with a significantly higher OS, but no improved EFS in high‐risk patients. The number of CD34+ progenitors infused had no influence on the incidence of acute or chronic GVHD. J. Clin. Apheresis 28:349–355, 2013. © 2013 Wiley Periodicals, Inc.
Analytic derivatives for the XYG3 type of doubly hybrid density functionals: Theory, implementation, and assessment
Authors: Su Neil Qiang , Zhang Igor Ying , Xu Xin
Published: May 2013

We present a theoretical development of the equations required to perform an analytic geometry optimization of a molecular system using the XYG3 type of doubly hybrid (xDH) functionals. In contrast to the well‐established B2PLYP type of DH functionals, the energy expressions in the xDH functionals are constructed by using density and orbital information from another standard Kohn–Sham (KS) functional (e.g., B3LYP) for doing the self‐consistent field calculations. Thus, the xDH functionals are nonvariational in both the hybrid density functional part and the second‐order perturbation part, each of which requires formally to solve a coupled‐perturbed KS equation. An implementation is reported here which combines the two parts by defining a total Lagrangian such that only a single set of the Z‐vector equations need to be solved. The computational cost with our implementation is of the same order as those for the conventional Møller–Plesset theory to the second order (MP2) and B2PLYP. Systematic test calculations are provided for covalently bonded molecules as well as compounds involving the intramolecular nonbonded interactions for the main group elements. Satisfactory performance of the xDH functionals demonstrates that the extra computer time on top of the conventional KS procedure is well‐invested, in particular, when the standard KS functionals and MP2 as well, are problematic. © 2013 Wiley Periodicals, Inc.
Angiotensin Receptor Blockers and Risk of Prostate Cancer Among United States Veterans
Authors: Rao Gowtham A. , Mann Joshua R. , Bottai Matteo , Uemura Hiroji , Burch James B. , Bennett Charles Lee , Haddock Kathlyn Sue , Hébert James R.
Published: May 2013

To address concerns regarding increased risk of prostate cancer (PrCA) among angiotensin receptor blocker (ARB) users, we used national retrospective data from the Department of Veterans Affairs (VA) through the Veterans Affairs Informatics and Computing Infrastructure. We identified a total of 543,824 unique Veterans who were classified into either ARB treated or not‐treated in 1:15 ratio. The two groups were balanced using inverse probability of treatment weights. A double‐robust cox‐proportional hazards model was used to estimate the hazard ratio for PrCA incidence. To evaluate for a potential Gleason score stage migration, we conducted weighted Cochrane‐Armitage test. Post weighting, the rates of PrCA in treated and not‐treated groups were 506 (1.5%) and 8,269 (1.6%), respectively; representing a hazard ratio of (0.91, p‐value .049). There was no significant difference in Gleason scores between the two groups. We found a small, but statistically significant, reduction in the incidence of clinically detected PrCA among patients assigned to receive ARB with no countervailing effect on degree of differentiation (as indicated by Gleason score). Findings from this study support Food and Drug Administration's recent conclusion that ARB use does not increase risk of incident PrCA.
Thermospheric tidal effects on the ionospheric midlatitude summer nighttime anomaly using SAMI3 and TIEGCM
Authors: Chen C. H. , Lin C. H. , Chang L. C. , Huba J. D. , Lin J. T. , Saito A. , Liu J. Y.
Published: May 2013

This paper is the first study to employ a three‐dimensional physics‐based ionosphere model, SAMI3, coupled with the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) and Global Scale Wave Model to simulate the mesospheric and lower thermospheric tidal effects on the development of midlatitude summer nighttime anomaly (MSNA). Using this coupled model, the diurnal variation of MSNA electron densities at 300 km altitude is simulated on both June solstice (day of year (DOY) 167) and December solstice (DOY 350) in 2007. Results show successful reproduction of the southern hemisphere MSNA structure including the eastward drift feature of the southern MSNA, which is not reproduced by the default SAMI3 runs using the neutral winds provided by the empirical Horizontal Wind Model 93 neutral wind model. A linear least squares algorithm for extracting tidal components is utilized to examine the major tidal component affecting the variation of southern MSNA. Results show that the standing diurnal oscillation component dominates the vertical neutral wind manifesting as a diurnal eastward wave‐1 drift of the southern MSNA in the local time frame. We also find that the stationary planetary wave‐1 component of vertical neutral wind can cause diurnal variation of the summer nighttime electron density enhancement around the midlatitude ionosphere.
Upstream ultra‐low frequency waves in Mercury's foreshock region: MESSENGER magnetic field observations
Authors: Le Guan , Chi Peter J. , Blanco‐Cano Xochitl , Boardsen Scott , Slavin James A. , Anderson Brian J. , Korth Haje
Published: May 2013

Mercury's bow shock is unique in our solar system as it is produced by low Mach number solar wind blowing over a small magnetized body. The availability of MESSENGER orbiter data enables us for the first time to conduct an in‐depth study of upstream waves in Mercury's foreshock. This paper reports first results of an observational study of upstream ULF waves in Mercury's foreshock using high‐time resolution magnetic field data from the MESSENGER spacecraft to understand the general morphology of these waves. We find that the most common wave phenomenon in Mercury's foreshock has frequencies ~ 2 Hz, with properties similar to the 1 Hz whistler waves in the Earth's foreshock. Their generation appears to be generic to the shock and not affected by the weak strength and small size of Mercury's bow shock. On the other hand, the most common wave phenomenon in the Earth's foreshock is the large‐amplitude 30 second waves, identified as fast magnetosonic waves generated by backstreaming ions. Similar waves at Mercury have wave frequencies at ~ 0.3 Hz, but occur only sporadically. The general lack of strong “30 second” magnetosonic waves at Mercury can be attributed to the lack of strong backstreaming ions due to a weak bow shock and not enough time for wave growth due to the small foreshock size. Superposed on the “1 Hz” whistler waves, there are short bursts of spectral peaks at ~ 0.8 Hz that are new and have not been reported previously in Mariner 10 data.
Boreal winter low‐frequency variability in CMIP5 models
Authors: Lee Yun‐Young , Black Robert X.
Published: May 2013

This study assesses the capability of CMIP5 models in representing primary modes of boreal winter extratropical low‐frequency variability. Rotated principal component analysis is applied to monthly mean output from historical simulations of 14 plus two variants models and National Centers for Environmental Prediction–National Center for Atmospheric Research reanalyses (NNR) to isolate the leading patterns of variability in 500 hPa height. For each model data set, North Atlantic Oscillation (NAO)‐like and Pacific‐North American (PNA)‐like patterns are identified using pattern correlation analysis (against NNR patterns). The relative pattern correspondence among CMIP5 models and reanalyses is further quantified via cluster analyses of the rotated empirical orthogonal function, NAO‐like, and PNA‐like patterns, respectively. For both NAO and PNA, 18.8% of the model patterns lie within the same cluster as NNR. Composite structural differences among clusters chiefly consist of (a) spatial displacements of or (b) regional magnitude disparities in the primary anomaly features. While all models replicate the basic aspects of PNA, a small minority of models fails to replicate NAO pattern. Overall, the best performing model is the “GFDL‐ESM2G.” Interestingly, models having a well‐resolved stratosphere generally perform more poorly than those without. Model biases in low‐frequency mode structure have important consequences for the representation of associated regional anomalies in surface air temperature and storm track behavior. Those differences among clusters are linked to variations in dynamical structures and their relation to the climatological‐mean flow. It is concluded that some state‐of‐the‐art models have important deficiencies in representing low‐frequency variability and some of these deficiencies are associated with the failure of models to adequately replicate the observed climatological stationary waves.
Characterization of CTX‐M‐type extended‐spectrum beta‐lactamase in clinical clones of Escherichia coli in Southwest China
Authors: Zhao Wei‐Dong , Yan Ping , Guan Hai‐Ning , Zhang Qun‐Zhi
Published: May 2013

The rapid and widespread dissemination of CTX‐M‐type extended‐spectrum beta‐lactamases (ESBLs) Escherichia coli in most of the provinces in China has been previously characterized; however, these enzymes have been rarely reported among minority regions. A prospective study using 180 E. coli clones from three hospitals in the minority district of Dali Bai was conducted between January 2009 and June 2010 to characterize the profiles of blaCTX‐M‐producing E. coli. Overall, 87 of the isolates (48.3%) encoded the resistance phenotypes of ESBLs. Among these 87 isolates, 56 (64.4%) exconjugants were successfully obtained. The genotypes of blaCTX‐M were evaluated by PCR and DNA sequencing. In total, 22 and 53 E. coli isolates possessed CTX‐M cluster 1 and CTX‐M cluster 9, respectively. Five blaCTX‐M subtypes were detected, namely, blaCTX‐M3 (n = 12), blaCTX‐M15 (n = 4), blaCTX‐M22 (n = 2), blaCTX‐M14 (n = 41), and blaCTX‐M9 (n = 8). The broth microdilution method was performed to determine the minimal inhibitory concentration of 13 antibiotics. Most CTX‐M producers were multiply resistant to both β‐lactam and non‐β‐lactam antibiotics. Imipenem showed excellent activity, and only one isolate harboring blaCTX‐M14+CTX‐M3 exhibited resistance to it. In conclusion, there seems to be great concern regarding the distribution and drug resistance of CTX‐M ESBL‐producing E. coli.