bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dimethylarginines: their vascular and metabolic roles in Africans and Caucasians
Authors: Schutte Aletta E , Schutte Rudolph , Huisman Hugo W , van Rooyen Johannes M , Fourie Carla M T , Malan Leoné , Malan Nico T , Schwedhelm Edzard , Strimbeanu Sebastian , Anderssohn Maike , Böger Rainer H 
Published: December 2009

ObjectiveAlarming increases in hypertension and type 2 diabetes among Africans accentuate the need to identify factors that could serve as targets for prevention or treatment. In Caucasian populations, asymmetric dimethylarginine (ADMA), the predominant endogenous nitric oxide synthase inhibitor, is associated with cardiovascular disease and insulin resistance (IR). ADMA's counterpart, symmetric dimethylarginine (SDMA), originally thought to be inert, was recently also linked with cardiovascular risk. Since little information regarding ADMA or SDMA is available for Africans, our aim was to explore the relationships of ADMA and SDMA with measures of arterial stiffness and IR in Africans and Caucasians from South Africa.MethodsThe study consisted of 235 nonsmoking, nondiabetic, nonobese, human immunodeficiency virus-uninfected Africans (n=64) and Caucasians (n=171), aged 20–70 years. We measured blood pressure, pulse wave velocity, ADMA, SDMA, and IR (homeostasis model assessment, HOMA).ResultsAfrican and Caucasian men had similar ADMA and SDMA, whereas Caucasian women had higher ADMA and SDMA than African women (P<0.05). African men and Caucasian women indicated strong correlations of ADMA with arterial stiffness (r=0.47, P=0.021; r=0.26, P=0.008), confirmed in multivariate analyses. Caucasian participants showed negative associations between SDMA and HOMA, being strongest in the men (r=−0.41; P=0.002).ConclusionOur results indicate that ADMA is independently associated with vascular dysfunction in African men and Caucasian women. A strong, independent negative association of SDMA with IR was found only in Caucasian participants. The molecular explanation for this is unclear, but these findings motivate experimental studies that could shed more light on these relationships.
Habitat Choice by Atlantic Salmon Parr in Relation to Turbulence at a Reach Scale
Authors: Enders Eva C. , Roy Mathieu L. , Ovidio Michaël , Hallot Éric J. , Boyer Claudine , Petit François , Roy André G. 
Published: December 2009

Abstract
The variables commonly used to describe the physical habitat of Atlantic salmon Salmo salar parr are average velocity, water depth, and substrate. A variety of micro- and mesohabitat models have been developed using these variables to assess habitat quality. However, Atlantic salmon parr live in highly turbulent streams and rivers in which intense fluctuations of water velocity occur. Laboratory experiments have shown that turbulence affects the behavior and energetics of fish. Nevertheless, habitat use in relation to the strong temporal variability of velocity in natural environments has rarely been studied. In this study, Atlantic salmon parr habitat was examined in relation to turbulence in the Patapédia River, Quebec. Rather than taking the usual approach of surveying a large population at one point in time, we used an intensive radiotelemetry tracking survey that focused on the habitat use of a few individual fish over an extended period. We analyzed habitat use in relation to several dynamic hydraulic variables. Our results revealed that under naturally turbulent conditions, the parr displayed high individual variability in their habitat use. Such heterogeneous use of habitat suggests that individuals are not constrained to a single habitat type. Furthermore, no differences were observed in habitat use among the four daily periods (dawn, day, dusk, and night) for individual parr.
Behavior of Steelhead Fry in a Laboratory Stream is Affected by Fish Density but Not Rearing Environment
Authors: Riley Stephen C. , Tatara Christopher P. , Berejikian Barry A. , Flagg Thomas A. 
Published: December 2009

Abstract
We quantified the aggression, feeding, dominance, position choice, and territory size of naturally reared steelhead Oncorhynchus mykiss fry stocked with two types of hatchery-reared fry (from conventional and enriched rearing environments) at two densities in experimental flumes to determine how rearing environment and fish density affect the behavior of steelhead fry. We found that fry density had a significant effect on most response variables but that rearing treatment did not. The rates of threats and attacks were positively correlated with fry density, but the overall feeding rate was negatively correlated. Naturally reared fry were dominant more often at low densities, and hatchery-reared fry were dominant more often at high densities. There were no significant effects of hatchery rearing treatment on aggression, feeding, dominance, or territory size. The only significant effect of rearing treatment was on the position of naturally reared fry, which occupied more upstream positions when stocked with conventional than with enriched hatchery-reared fry. Overall, rearing environment had relatively little influence on the behavior of steelhead fry. Our results indicate that stocking hatchery-reared steelhead fry at low densities may have effects on similar-size wild fish comparable to an equivalent increase in the density of wild fish. We suggest that releasing hatchery-reared steelhead fry as a supplementation strategy may have few direct negative ecological effects on wild fry.
Frequency of Scabies in Iraq: Survey in a Dermatology Clinic
Authors: Alsamarai Abdulghani Mohamad 
Published: December 2009

Background: The burden of scabies is highest in tropical countries, but recent data from Iraq are scanty. Objective: To estimate the frequency of scabies in patients of a dermatology clinic in central Iraq. Methodology: The study was conducted in Tikrit (Iraq), between May 2007 and February 2008. A total of 1,194 patients presenting to a dermatology clinic were included in the study. Results: During the study period, 132 [1.1%] patients with scabies were identified. The frequency was 13.5% in males and 8.6% in females [P = 0.007]. Frequency in children was 15.6% and 9.8% in adults [P = 0.007]. About 91% of cases were younger than 45 years. The treatment of scabies cases with 5% permethrin cream resulted in a cure rate of 80.3% following a single application, and was increased to 95.5% after a second application. Cure was achieved in all cases after a third application. Conclusion: Prevalence of scabies was high in a dermatology clinic, and prisoners were identified as high-risk group. Mass treatment of scabies either by oral ivermectin or topical permethrin is suggested.
Indirect patient expenses for antituberculosis treatment in Tijuana, Mexico: is treatment really free?
Authors: Guzmán-Montes Gema Yolanda , Heras-Ovalles Renata , Laniado-Laborín Rafael 
Published: December 2009

Background: One of the main problems faced by the Mexican National Tuberculosis Program is the high rate of patients abandoning treatment. This study aimed to determine the magnitude of unaccounted costs of tuberculosis (TB) treatment in Tijuana, Mexico. Methodology: Subjects were recruited at 21 health centres. Patients had confirmed active pulmonary TB, had been on treatment for more than 12 weeks, and were aged 18 years and older. The questionnaire provided information about demographics, past and current episodes of TB, and various categories of expenses. Results: The study included 180 patients as follows: 48 had been diagnosed with tuberculosis in the past (26.6%) and had either currently relapsed or failed treatment; 160 (88.8%) were under directly observed therapy (DOT); 131 (72.8%) attended a health centre; and the rest received directly observed treatment at home. The daily cost of transportation to the health centre was MXN $25.88 + 3.22 (1 USD = 13 MXN). Thirty-two patients (17.8%) had to buy medication at least once, with a monthly medication expense of MXN $440.5 + 40.3. Patients receiving DOT at the health centre reported daily food and beverages expenses, spending MXN $56.5 + 10.1. Forty-two patients reported laboratory testing expenses, on average MXN $558.8 + 85.8 per month. Eighty patients (42.4%) reported expenses on radiographic/ultrasound studies, on average MXN $562.9 + 72.1 per six-month regimen. Conclusions TB diagnosis and treatment posed a significant economic burden on patients in terms of both cost and affordability; clinic-based DOT may contribute disproportionately to the costs incurred by patients.
Trends in antimicrobial resistance in Shigella species in Karachi, Pakistan
Authors: Khan Erum , Jabeen Kausar , Ejaz Muslima , Siddiqui Jaweriah , Shezad Muhammad Farrukh , Zafar Afia 
Published: December 2009

Background: Shigellosis is a common cause of morbidity, especially in the very young and old, in developing countries. The disease is treated with antibiotics. Surveillance of antimicrobial resistance trends is essential owing to the global emergence of antimicrobial resistance. Methodology: The study involved 1,573 isolates of Shigella species (1996-2007) that were analyzed for trends in antimicrobial resistance. Results: The majority of the specimens (1046; 66.5%) were from the pediatric population, and of these 887 (84.8%) were under 5 years of age (p = 0.001). S. flexineri was the most frequent species (54.5%) isolated. Isolation of S. sonnei increased from 15.4 % (1996) to 39% (2007) (p = 0.001). Although none of the isolates was found sensitive to all the antibiotics tested, 58% (n =9 07) were resistant to ampicillin and 85% (n = 1,338) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Out of a total of 198 (12.6%) nalidixic acid resistant isolates, 6 (3.0%) were also resistant to ofloxacin. Overall 1.7 % of isolates were resistant to ofloxacin, 2.4% to ceftriaxone and 2.3% were resistant to combination of ampicillin, nalidixic acid and TMP-SMX. Conclusion: Ofloxacin is still an effective drug for treatment of acute shigellosis in Pakistan. Emergence of resistance to ceftriaxone in Shigella may have grave implications in treatment of severe shigellosis in very young patients.
The Daunting Practicalities of In-office Pediatric Influenza Vaccination: 2009–2010
Authors: Block Stan L. 
Published: December 2009

CME Educational Objectives

1.
Identify the key barriers to successful delivery of influenza vaccine in the private office setting.

2.
Assess proven strategies that improve influenza vaccine delivery in the office setting.

3.
Delineate the unique stresses placed on the private office as a result of the need to delivery H1N1 vaccine this influenza season.
The New Fundamentals in Nursing: Introducing Beginning Quality and Safety Education for Nurses' Competencies
Authors: Preheim Gayle J. , Armstrong Gail E. , Barton Amy J. 
Published: December 2009

This article describes the redesign of the fundamentals of nursing course using an organizing framework and teaching strategies identified in the Quality and Safety Education for Nurses (QSEN) initiative. Six QSEN competencies (patient-centered care, teamwork and collaboration, evidence-based practice, quality improvement, safety, and informatics) are essential for nursing practice. Beginning knowledge, skills, and attitudes (KSAs) associated with each competency were identified in a preliminary Delphi survey as important to incorporate early in prelicensure nursing curricula. Redesign requires a shift in focus from task-training and psychomotor skills development to incorporation of a systems context, reflecting redefined values and interventions associated with safety, quality, and professional nursing roles.
A course revision, based on the QSEN competencies definitions, selected beginning KSAs, exemplar resources, and teaching strategies, is described. The reframing of fundamentals of nursing is essential to prepare new graduates for contemporary practice.
Carbohydrate‐Oligonucleotide Conjugates
Authors: Pourceau Gwladys , Meyer Albert , Vasseur Jean‐Jacques , Morvan François 
Published: December 2009

AbstractThis unit describes a strategy for attaching two mannose and two galactose residues to an oligonucleotide. This conjugation can be performed at the 5′‐end of the oligonucleotide sequence, using modified phosphoramidites. First, the oligonucleotide scaffold is synthesized on solid support using a DNA synthesizer, with commercially available and modified phosphoramidites. After the first “click” reaction with a galactosylated azide derivative on solid support, the bromine atoms are replaced with azides and a second click reaction is performed with propargylated mannose either on solid support or in solution. Additionally, using a monoalkynated solid support, the conjugation with carbohydrate residues can be performed at the 3′‐end of the oligonucleotide according to a similar protocol. Curr. Protoc. Nucleic Acid Chem. 39:4.38.1‐4.38.25. © 2009 by John Wiley & Sons, Inc.
Chemical Modification of siRNA
Authors: Deleavey Glen F. , Watts Jonathan K. , Damha Masad J. 
Published: December 2009

AbstractThe ability to manipulate the RNA interference (RNAi) machinery to specifically silence the expression of target genes could be a powerful therapeutic strategy. Since the discovery that RNAi can be triggered in mammalian cells by short double‐stranded RNAs (small interfering RNA, siRNA), there has been a tremendous push by researchers, from academia to big pharma, to move siRNAs into clinical application. The challenges facing siRNA therapeutics are significant. The inherent properties of siRNAs (polyanionic, vulnerable to nuclease cleavage) make clinical application difficult due to poor cellular uptake and rapid clearance. Side effects of siRNAs have also proven to be a further complication. Fortunately, numerous chemical modification strategies have been identified that allow many of these obstacles to be overcome. This unit will present an overview of (1) the chemical modifications available to the nucleic acid chemist for modifying siRNAs, (2) the application of chemical modifications to address specific therapeutic obstacles, and (3) the factors that must be considered when assessing the activity of modified siRNAs. Curr. Protoc. Nucleic Acid Chem. 39:16.3.1‐16.3.22. © 2009 by John Wiley & Sons, Inc.
Bifunctional Acid–Base Ionic Liquid Organocatalysts with a Controlled Distance Between Acid and Base Sites
Authors: Boronat Mercedes , Climent Maria J. , Corma Avelino , Iborra Sara , Montón Raquel , Sabater Maria J. 
Published: December 2009

AbstractBifunctional acid–base ionic liquid organocatalysts with different distances between the two sites have been synthesised, and their activity for the Knoevenagel condensation has been tested. As has been found to be the case with enzymes, the distance between the acidic and basic sites determines the activity of the bifunctional organocatalyst, and at the optimal distance the reaction rate increases by two orders of magnitude with respect to the purely acidic or basic counterpart organocatalysts. The experimental results have been rationalised through the study of the reaction mechanism of the Knoevenagel condensation between malononitrile and benzaldehyde by means of DFT calculations. It has been found that it consists of two consecutive steps. First, deprotonation of malononitrile on the basic site to obtain a methylene carbanion intermediate takes place, and second, co‐adsorption and activation of benzaldehyde on the acid centre of this intermediate followed by the CC bond‐formation reaction. The calculations and the kinetic study indicate that there is an inversion of the rate‐controlling step when the distance between the acidic and the basic sites is modified, with a direct implication on the reaction rate.
Photochemical Reduction of Carbon Dioxide Catalyzed by a Ruthenium‐Substituted Polyoxometalate
Authors: Khenkin Alexander M. , Efremenko Irena , Weiner Lev , Martin Jan M. L. , Neumann Ronny 
Published: December 2009

AbstractA polyoxometalate of the Keggin structure substituted with RuIII, 6Q5[RuIII(H2O)SiW11O39] in which 6Q=(C6H13)4N+, catalyzed the photoreduction of CO2 to CO with tertiary amines, preferentially Et3N, as reducing agents. A study of the coordination of CO2 to 6Q5[RuIII(H2O)SiW11O39] showed that 1) upon addition of CO2 the UV/Vis spectrum changed, 2) a rhombic signal was obtained in the EPR spectrum (gx=2.146, gy=2.100, and gz=1.935), and 3) the 13C NMR spectrum had a broadened peak of bound CO2 at 105.78 ppm (Δ1/2=122 Hz). It was concluded that CO2 coordinates to the RuIII active site in both the presence and absence of Et3N to yield 6Q5[RuIII(CO2)SiW11O39]. Electrochemical measurements showed the reduction of RuIII to RuII in 6Q5[RuIII(CO2)SiW11O39] at −0.31 V versus SCE, but no such reduction was observed for 6Q5[RuIII(H2O)SiW11O39]. DFT‐calculated geometries optimized at the M06/PC1//PBE/AUG‐PC1//PBE/PC1‐DF level of theory showed that CO2 is preferably coordinated in a side‐on manner to RuIII in the polyoxometalate through formation of a RuO bond, further stabilized by the interaction of the electrophilic carbon atom of CO2 to an oxygen atom of the polyoxometalate. The end‐on CO2 bonding to RuIII is energetically less favorable but CO2 is considerably bent, thus favoring nucleophilic attack at the carbon atom and thereby stabilizing the carbon sp2 hybridization state. Formation of a O2C–NMe3 zwitterion, in turn, causes bending of CO2 and enhances the carbon sp2 hybridization. The synergetic effect of these two interactions stabilizes both Ru–O and C–N interactions and probably determines the promotional effect of an amine on the activation of CO2 by [RuIII(H2O)SiW11O39]5−. Electronic structure analysis showed that the polyoxometalate takes part in the activation of both CO2 and Et3N. A mechanistic pathway for photoreduction of CO2 is suggested based on the experimental and computed results.
Mechanistic Investigation of the Dipolar [2+2] Cycloaddition–Cycloreversion Reaction between 4‐(N,N‐Dimethylamino)phenylacetylene and Arylated 1,1‐Dicyanovinyl Derivatives To Form Intramolecular Charge‐Transfer Chromophores
Authors: Wu Yi‐Lin , Jarowski Peter D. , Schweizer W. Bernd , Diederich François 
Published: December 2009

AbstractThe kinetics and mechanism of the formal [2+2] cycloaddition–cycloreversion reaction between 4‐(N,N‐dimethylamino)phenylacetylene (1) and para‐substituted benzylidenemalononitriles 2 b–2 l to form 2‐donor‐substituted 1,1‐dicyanobuta‐1,3‐dienes 3 b–3 l via the postulated dicyanocyclobutene intermediates 4 b–4 l have been studied experimentally by the method of initial rates and computationally at the unrestricted B3LYP/6‐31G(d) level. The transformations were found to follow bimolecular, second‐order kinetics, with ${{\rm{\Delta }}H_{{\rm{exp}}}^{ {\ne} } }$=13–18 kcal mol−1, ${{\rm{\Delta }}S_{{\rm{exp}}}^{ {\ne} } }$≈−30 cal K−1 mol−1, and ${{\rm{\Delta }}G_{{\rm{exp}}}^{ {\ne} } }$=22–27 kcal mol−1. These experimental activation parameters for the rate‐determining cycloaddition step are close to the computational values. The rate constants show a good linear free energy relationship (ρ=2.0) with the electronic character of the para‐substituents on the benzylidene moiety in dimethylformamide (DMF), which is indicative of a dipolar mechanism. Analysis of the computed structures and their corresponding solvation energies in acetonitrile suggests that the rate‐determining attack of the nucleophilic, terminal alkyne carbon onto the dicyanovinyl electrophile generates a transient zwitterion intermediate with the negative charge developing as a stabilized malononitrile carbanion. The computational analysis predicted that the cycloreversion of the postulated dicyanocyclobutene intermediate would become rate‐determining for 1,1‐dicyanoethene (2 m) as the electrophile. The dicyanocyclobutene 4 m could indeed be isolated as the key intermediate from the reaction between alkyne 1 and 2 m and characterized by X‐ray analysis. Facile first‐order cycloreversion occurred upon further heating, yielding as the sole product the 1,1‐dicyanobuta‐1,3‐diene 3 m.
Positive Homotropic Allosteric Receptors for Neutral Guests: Annulated Tetrathiafulvalene–Calix[4]pyrroles as Colorimetric Chemosensors for Nitroaromatic Explosives
Authors: Park Jung Su , Le Derf Franck , Bejger Christopher M. , Lynch Vincent M. , Sessler Jonathan L. , Nielsen Kent A. , Johnsen Carsten , Jeppesen Jan O. 
Published: December 2009

AbstractThe study of positive homotropic allosterism in supramolecular receptors is important for elucidating design strategies that can lead to increased sensitivity in various molecular recognition applications. In this work, the cooperative relationship between tetrathiafulvalene (TTF)‐calix[4]pyrroles and several nitroaromatic guests is examined. The design and synthesis of new annulated TTF‐calix[4]pyrrole receptors with the goal of rigidifying the system to accommodate better nitroaromatic guests is outlined. These new derivatives, which display significant improvement in terms of binding constants, also display a positive homotropic allosteric relationship, as borne out from the sigmoidal nature of the binding isotherms and analysis by using the Hill equation, Adair equation, and Scatchard plots. The host–guest complexes themselves have been characterized by single‐crystal X‐ray diffraction analyses and studied by means of UV‐spectroscopic titrations. Investigations into the electronic nature of the receptors were made by using cyclic voltammetry; this revealed that the binding efficiency was not strictly related to the redox potential of the receptor. On the other hand, this work serves to illustrate how cooperative effects may be used to enhance the recognition ability of TTF‐calix[4]pyrrole receptors. It has led to new allosteric systems that function as rudimentary colorimetric chemosensors for common nitroaromatic‐based explosives, and which are effective even in the presence of potentially interfering anions.
Belastbare Enzympräparate für die technische Biokatalyse
Authors: Ansorge‐Schumacher M. B. , Nieguth R. , Wiemann L. O. , Weißhaupt P. , Thum O. , Eckstein M. 
Published: December 2009

AbstractBei einer technischen Nutzung von Biokatalysatoren mit adsorptiv immobilisierten Enzymen sind die Desorptionsbeständigkeit der Enzyme und die mechanische Stabilität der Träger von besonderer Bedeutung. Die daraus resultierenden Limitierungen können durch eine Stabilisierung der Immobilisate mit Silicon weitgehend überwunden werden. Dies wurde anhand der Lipase B von C. antarctica (CALB), adsorbiert auf einem makroporösen Träger aus Polymethylmethacrylat, demonstriert. Im Zuge der experimentellen Evaluierung wurden sowohl der Einfluss verschiedener Siliconmengen, als auch unterschiedlicher Monomerkombinationen auf Trägermorphologie, katalytische Aktivität und mechanische Belastbarkeit untersucht. Dabei konnte eine deutliche Verminderung der Desorption des Enzyms vom Träger sowie eine Stabilisierung gegenüber mechanischem Stress, wie er in Rührwerksreaktoren auftritt, nachgewiesen werden.
Mikrobielle Umsetzung von β‐Phenylalanin mittels neuer Transaminasen
Authors: Brucher B. , Syldatk C. , Rudat J. 
Published: December 2009

AbstractBei der Untersuchung der Metabolisierung aromatischer β‐Aminosäuren wurden bei zahlreichen Bakterienstämmen eine stereoselektive Aufnahme sowie neuartige Transaminasen zur Verwertung dieser Verbindungen entdeckt. Racematspaltung mittels stereoselektiven Transports sowie Transaminierung von β‐Ketosäuren könnten neue Wege zur Gewinnung enantiomerenreiner β‐Aminosäuren darstellen. Gegenüber der Racematspaltung würde die Transaminierung eine wesentlich höhere Ausbeute des gewünschten Isomers ermöglichen.