bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of angiotensin II-induced ERK1/2 activation in fetal cardiomyocytes
Authors: Yin Xing , Hu Lian , Feng Hao , Krsmanovic Lazar Z. , Catt Kevin J. 
Published: August 2010

AbstractFetal cardiomyocytes have been utilized in studies on myocardial repair in the damaged hearts of rodents and other species. Changes in angiotensin II (Ang II) receptor expression, especially decline of its type II receptor (AT2), are known to occur during the growth of cardiomyocytes from fetus to adult. However, the extent to which changes in the signaling pathways of Ang II type I (AT1) and AT2 receptors via p42/44 mitogen-activated protein kinase (ERK1/2) activation affect the physiological and pathophysiological functions in cardiomyocytes has not been defined. The roles of these receptors were analyzed by confocal fluorescence microscopy, immunoblot analysis, reverse transcription PCR, measurement of intracellular 3′,5′-cyclic AMP levels and siRNA technology in cultured rat fetal cardiomyocytes. These studies revealed that Gq is required for Ang II-induced ERK1/2 activation via the synergy of AT1 and AT2 receptors. It has also been shown that phospholipase Cβ1, protein kinase Cα and protein kinase A mediate the feedback inhibition of ERK1/2 activation via c-Raf and/or other intermediate signaling molecules. The observed mechanism of Ang II-induced ERK1/2 activation in fetal cardiomyocytes could be relevant to the understanding of cardiomyocyte development and turnover, as well as clinical approaches using protein- and cell-based therapy for diseases such as heart failure.
Kinetic and Mechanistic Aspects of Osmium(VIII) Catalyzed Oxidation of DL-ornithine by Copper(III) Periodate Complex in Aqueous Alkaline Medium
Authors: Abbar Jyothi C. , Malode Shweta J. , Nandibewoor Sharanappa T. 
Published: August 2010

AbstractThe oxidation of DL-ornithine monohydrochloride (OMH) by diperiodatocuprate(III) (DPC) has been investigated in the presence of osmium(VIII) catalyst in aqueous alkaline medium at a constant ionic strength of 0.20 mol dm−3spectrophotometrically. The reaction exhibits 1:4 stoichiometry i.e., [OMH]: [DPC]. The order of the reaction with respect to [DPC] was unity while the order with respect to [OMH] was less than unity over the concentration range studied. The rate increased with an increase in [OH–] and decreased with an increase in [IO4−]. The order with respect to [Os(VIII)] was unity. The reaction rates revealed that Os(VIII) catalyzed reaction was about nine-fold faster than the uncatalyzed reaction. The oxidation products were identified by spectral analysis. Suitable mechanism has been proposed. The reaction constants involved in the different steps of the reaction mechanism were calculated. The catalytic constant (KC) was also calculated at different temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined. Kinetic experiments suggest that [OsO4(OH)2]2−is the reactive Os(VIII) species and [Cu(H2IO6)(H2O)2] is the reactive copper(III) species.
Ostwald´s Rule and the Principle of the Shortest Way
Authors: Zimmermann Herbert W. 
Published: August 2010

AbstractWe consider a substance X with two monotropic modifications 1 and 2 of different thermodynamic stability ΔH1< ΔH2. Ostwald´s rule states that first of all the instable modification 1 crystallizes on cooling down liquid X, which subsequently turns into the stable modification 2. Numerous examples verify this rule, however what is its reason? Ostwald´s rule can be traced back to the principle of the shortest way. We start with Hamilton´s principle and the Euler-Lagrange equation of classical mechanics and adapt it to thermodynamics. Now the relevant variables are the entropy S, the entropy production P = dS/dt, and the time t. Application of the Lagrangian F(S, P, t) leads us to the geodesic line S(t). The system moves along the geodesic line on the shortest way I from its initial non-equilibrium state i of entropy Sito the final equilibrium state f of entropy Sf. The two modifications 1 and 2 take different ways I1and I2. According to the principle of the shortest way, I1< I2is realized in the first step of crystallization only. Now we consider a supercooled sample of liquid X at a temperature T just below the melting point of 1 and 2. Then the change of entropy ΔS1= Sf 1- Si 1on crystallizing 1 can be related to the corresponding chang of enthalpy by ΔS1= ΔH1/T. Now it can be shown that the shortest way of crystallization I1corresponds under special, well-defined conditions to the smallest change of entropy ΔS1< ΔS2and thus enthalpy ΔH1< ΔH2. In other words, the shortest way of crystallization I1really leads us to the instable modification 1. This is Ostwald´s rule.
Sources and Cycling of Tropospheric Hydroxyl Radicals – An Overview
Authors: Elshorbany Yasin , Barnes Ian , Becker Karl H. , Kleffmann Jörg , Wiesen Peter 
Published: August 2010

Abstract
The hydroxyl radical is the principal oxidizing agent in the troposphere. It controls and determines the oxidizing power of the atmosphere and thus governs the atmospheric lifetime of many species, and their potential to contribute to climate change, air pollution and ozone formation. Owing to the development of new measurement techniques and the discovery of new reaction mechanisms, the understanding of the OH chemistry has witnessed significant advances during the last decades. This article presents a comprehensive review of the current understanding of OH radical chemistry with an outlook to future work in this active research area of atmospheric chemistry.Among the different OH radical initiation sources, e.g. O3 photolysis, HCHO photolysis, ozonolysis of alkenes and the photolysis of nitrous acid (HONO), the latter has been shown in recent field and model studies to make a major contribution to tropospheric OH levels. New photochemical sources of HONO have been discovered in the laboratory which can explain unexpectedly high concentrations of HONO observed in the atmosphere during daytime. A detailed analysis of HONO sources in the atmosphere is presented. OH radicals react with volatile organic compounds (VOCs) in a complex cycle regenerating OH radicals in the propagation cycle. Recent field and model studies show that the OH radical propagation cycle is balanced for high NOx conditions. Thus, radical losses by reactions with VOCs are balanced by OH formation through the reaction HO2+NO. However, studies at low NO and high VOC levels imply that unknown radical sources of OH exist in rural and forested areas. Possible sources of OH radicals under these conditions are discussed.
An Experimental and Theoretical Study of the Reaction Between NH(X3Σ−) + SO(X3Σ−)
Authors: Blitz Mark A. , Shannon Robin J. , Marshall Paul , Pilling Michael J. 
Published: August 2010

Abstract
The kinetics of the reaction between NH(X3Σ–) + SO(X3Σ–) have been studied over the range 295–703 K using pulsed laser photolysis / laser induced fluorescence in 100 Torr He. The rate coefficient is (5.0±2.0)×10−11 cm3 molecule−1 s−1, and is independent of temperature within experimental scatter. Electronic structure calculations show that reaction proceeds via bound intermediates to form NS + OH and NO + SH as the major bimolecular products. An RRKM / master equation analysis shows that stabilization of the intermediates is negligible at the pressures investigated (<104 Torr), so that the overall rate coefficient is independent of pressure. The calculations show that the main product channel under combustion conditions is NS + OH. Attempts to observe NS under the experimental conditions were unsuccessful. The experimental decay data are consistent with the occurrence of the reaction NH2 + Cl → NH + HCl at temperatures above 500 K; approximate Arrhenius parameters are provided.
The Gas-phase Ozonolysis of 1-Penten-3-ol, (Z)-2-Penten-1-ol and 1-Penten-3-one: Kinetics, Products and Secondary Organic Aerosol Formation
Authors: O Dwyer M. A. , Carey T. J. , Healy R. M. , Wenger J. C. , Picquet-Varrault B. , Doussin J. F. 
Published: August 2010

Abstract
The gas-phase ozonolysis of the biogenic unsaturated compounds 1-penten-3-ol, (Z)-2-penten-1-ol and 1-penten-3-one has been investigated in two atmospheric simulation chambers. The following rate coefficients (in units of 10−17 cm3 molecule−1 s−1) were determined at atmospheric pressure and 293±2 K using an absolute rate method: 1-penten-3-ol, (1.64±0.15); (Z)-2-penten-1-ol, (11.5±0.66); 1-penten-3-one, (1.17±0.15). Reaction products were identified by in situ FTIR spectroscopy and gas chromatography – mass spectrometry (GC-MS). The major products and their average molar yields in the presence of a radical scavenger at relative humidity < 1% were: formaldehyde (0.49±0.02), 2-hydroxybutanal (0.46±0.03) and propanal (0.15±0.02) from 1-penten-3-ol; propanal (0.39±0.03) and glycolaldehyde (0.43±0.04) from (Z)-2-penten-1-ol; formaldehyde (0.37±0.02) and 2-oxobutanal (0.49±0.03) from 1-penten-3-one. The formation of secondary organic aerosol was also observed with yields ranging from 0.13–0.17 for the unsaturated alcohols. Significantly lower yields of around 0.03 were measured for 1-penten-3-one. The results of this work are used to determine atmospheric lifetimes and reaction mechanisms for the gas-phase ozonolysis of 1-penten-3-ol, (Z)-2-penten-1-ol and 1-penten-3-one. The broader atmospheric implications of this work are also discussed.
Promoter Strength Influences the S Phase Requirement for Establishment of Silencing at theSaccharomyces cerevisiaeSilent Mating Type Loci
Authors: Ren Jie , Wang Chia-Lin , Sternglanz Rolf 
Published: August 2010

AbstractIn Saccharomyces cerevisiae, the two cryptic mating type loci, HML and HMR, are transcriptionally silent. Previous studies on the establishment of silencing at HMR identified a requirement for passage through S phase. However, the underlying mechanism for this requirement is still unknown. In contrast to HMR, we found that substantial silencing of HML could be established without passage through S phase. To understand this difference, we analyzed several chimeric HM loci and found that promoter strength determined the S phase requirement. To silence a locus with a strong promoter such as the a1/a2 promoter required passage through S phase while HM loci with weaker promoters such as the α1/α2 or TRP1 promoter did not show this requirement. Thus, transcriptional activity counteracts the establishment of silencing but can be overcome by passage through S phase.
A Two-Pathway Analysis of Meiotic Crossing Over and Gene Conversion inSaccharomyces cerevisiae
Authors: Stahl Franklin W , Foss Henriette M 
Published: August 2010

AbstractSeveral apparently paradoxical observations regarding meiotic crossing over and gene conversion are readily resolved in a framework that recognizes the existence of two recombination pathways that differ in mismatch repair, structures of intermediates, crossover interference, and the generation of noncrossovers. One manifestation of these differences is that simultaneous gene conversion on both sides of a recombination-initiating DNA double-strand break (“two-sidedness”) characterizes only one of the two pathways and is promoted by mismatch repair. Data from previous work are analyzed quantitatively within this framework, and a molecular model for meiotic double-strand break repair based on the concept of sliding D-loops is offered as an efficient scheme for visualizing the salient results from studies of crossing over and gene conversion, the molecular structures of recombination intermediates, and the biochemical competencies of the proteins involved.
Early Medical and Behavioral Characteristics of NICU Infants Later Classified With ASD
Authors: Karmel Bernard Z. , Gardner Judith M. , Meade Lauren Swensen , Cohen Ira L. , London Eric , Flory Michael J. , Lennon Elizabeth M. , Miroshnichenko Inna , Rabinowitz Simon , Parab Santosh , Barone Anthony , Harin Anantham 
Published: August 2010

OBJECTIVES:
Recent evidence suggests higher prevalence of autism spectrum disorder (ASD) in NICU graduates. This aim of this study was to identify retrospectively early behaviors found more frequently in NICU infants who went on to develop ASD.

METHODS:
Twenty-eight NICU graduates who later received a diagnosis of ASD were compared with 2169 other NICU graduates recruited from 1994 to 2005. They differed in gender, gestational age, and birth cohort. These characteristics were used to draw a matched control sample (n = 112) to determine which, if any, early behaviors discriminated subsequent ASD diagnosis. Behavioral testing at targeted ages (adjusted for gestation) included the Rapid Neonatal Neurobehavioral Assessment (hospital discharge, 1 month), Arousal-Modulated Attention (hospital discharge, 1 and 4 months), and Bayley Scales of Infant Development (multiple times, 4–25 months).

RESULTS:
At 1 month, children with ASD but not control children had persistent neurobehavioral abnormalities and higher incidences of asymmetric visual tracking and arm tone deficits. At 4 months, children with ASD had continued visual preference for higher amounts of stimulation than did control children, behaving more like newborns. Unlike control children, children with ASD had declining mental and motor performance by 7 to 10 months, resembling infants with severe central nervous system involvement.

CONCLUSIONS:
Differences in specific behavior domains between NICU graduates who later receive a diagnosis of ASD and matched NICU control children may be identified in early infancy. Studies with this cohort may provide insights to help understand and detect early disabilities, including ASD.
Human Papillomavirus Vaccination Practices: A Survey of US Physicians 18 Months After Licensure
Authors: Daley Matthew F. , Crane Lori A. , Markowitz Lauri E. , Black Sandra R. , Beaty Brenda L. , Barrow Jennifer , Babbel Christine , Gottlieb Sami L. , Liddon Nicole , Stokley Shannon , Dickinson L. Miriam , Kempe Allison 
Published: August 2010

OBJECTIVES:The objectives of this study were to assess, in a nationally representative network of pediatricians and family physicians, (1) human papillomavirus (HPV) vaccination practices, (2) perceived barriers to vaccination, and (3) factors associated with whether physicians strongly recommended HPV vaccine to 11- to 12-year-old female patients.METHODS:In January through March 2008, a survey was administered to 429 pediatricians and 419 family physicians.RESULTS:Response rates were 81% for pediatricians and 79% for family physicians. Ninety-eight percent of pediatricians and 88% of family physicians were administering HPV vaccine in their offices (P &lt; .001). Among those physicians, fewer strongly recommended HPV vaccination for 11- to 12-year-old female patients than for older female patients (pediatricians: 57% for 11- to 12-year-old patients and 90% for 13- to 15-year-old patients; P &lt; .001; family physicians: 50% and 86%, respectively; P &lt; .001). The most-frequently reported barriers to HPV vaccination were financial, including vaccine costs and insurance coverage. Factors associated with not strongly recommending HPV vaccine to 11- to 12-year-old female patients included considering it necessary to discuss sexuality before recommending HPV vaccine (risk ratio: 1.27 [95% confidence interval: 1.07–1.51]) and reporting more vaccine refusals among parents of younger versus older adolescents (risk ratio: 2.09 [95% confidence interval: 1.66–2.81]).CONCLUSIONS:Eighteen months after licensure, the vast majority of pediatricians and family physicians reported offering HPV vaccine. Fewer physicians strongly recommended the vaccine for younger adolescents than for older adolescents, and physicians reported financial obstacles to vaccination.
Knowledge on Pulse Oximetry Among Pediatric Health Care Professionals: A Multicenter Survey
Authors: Fouzas Sotirios , Politis Pantelis , Skylogianni Eleni , Syriopoulou Theodora , Priftis Kostas N. , Chatzimichael Athanassios , Anthracopoulos Michael B. 
Published: August 2010

OBJECTIVES:The objective of this study was to assess the knowledge on pulse oximetry among health care professionals involved in pediatric care.METHODS:A multiple-choice questionnaire was distributed to 505 pediatric health care professionals from 19 hospitals and health centers throughout Greece. Exploratory factor analysis was performed to identify underlying factors that could explain most of the variance of the responses. The mean test and factor scores were calculated and compared between clinical settings.RESULTS:The mean test score was 61.9 ± 18.1%. After factor analysis, 2 distinct groups of deficits in knowledge regarding pulse oximetry were identified: 1 was interpreted as relating to practical knowledge and the other to theoretical knowledge. The mean score of the items that assessed practical knowledge was 82.7 ± 12.5% and of those that assessed theoretical knowledge was 44.2 ± 21.7%. Pediatricians and family practitioners, participants from level 3 institutions, and health care professionals working in ICUs scored better, particularly on the items that assessed theoretical knowledge. Logistic regression analysis revealed that only participants from level 3 institutions and those from ICUs had a greater likelihood of achieving a higher score (total score odds ratio: level 3, 2.89, ICU, 8.13; theoretical knowledge odds ratio: level 3, 3.40, ICU, 10.95).CONCLUSIONS:Pediatric health care professionals have marked deficiencies in their knowledge on pulse oximetry, particularly in regard to the principles underlying the method and its limitations. Strategies that are directed at improving knowledge on pulse oximetry are urgently needed at all levels of experience in pediatric care.
Ridge Augmentation Using Recombinant Bone Morphogenetic Protein‐2 Techniques: An Experimental Study in the Canine
Authors: Thoma Daniel S. , Jones Archie , Yamashita Motofumi , Edmunds Ryan , Nevins Myron , Cochran David L. 
Published: August 2010

Background:The use of recombinant bone morphogenetic protein‐2 (rhBMP‐2) with a collagen carrier material has severe limitations in regards to space maintenance. The aim of this study was to test whether rhBMP‐2 combinations with allografts or a mesh enhance the regeneration of missing bone and the subsequent placement of dental implants.Methods:In five dogs, surgically created ridge defects were augmented using one of the following treatment modalities: 1) rhBMP‐2/absorbable collagen sponge (ACS) under a titanium mesh (Mesh); 2) rhBMP‐2/ACS plus canine freeze‐dried bone allograft; 3) rhBMP‐2/ACS plus canine demineralized freeze‐dried bone allograft (DFDBA); or 4) rhBMP‐2/ACS wrapped around a canine cancellous allograft block (Block Allograft). Eight weeks later, dental implants were placed in the augmented areas. The dogs were sacrificed 16 weeks after bone augmentation and specimens obtained for histologic and histomorphometric analyses.Results:All sites augmented with DFDBA, and one site with Block Allograft did not allow placement of dental implants. In all other sites, dental implants were placed. The area of regenerated bone ranged between 23.40 mm2(freeze‐dried bone allograft) and 35.16 mm2(Block Allograft). The greatest amount of bone was regenerated in the Block Allograft group ranging from 4.54 mm (at 1.5 mm), to 4.95 mm (at 3 mm), to 5.14 mm (at 4.5 mm). The least amount of bone was regenerated by the DFDBA group with values of 2.24 mm (at 1.5 mm), 2.84 mm (at 3 mm), and 3.34 mm (at 4.5 mm). Statistically significant differences were observed between DFDBA and block allograft at all three levels (P<0.001).Conclusion:The combination of rhBMP‐2 and a block allograft provides the greatest ridge width of the four treatment options used in this canine ridge augmentation model.
Bone Regeneration Around Implants in Periodontally Compromised Patients: A Randomized Clinical Trial of the Effect of Immediate Implant With Immediate Loading
Authors: Shibly Othman , Patel Nishith , Albandar Jasim M. , Kutkut Ahmad 
Published: August 2010

Background: This 2‐year randomized clinical trial compared bone regeneration and esthetic outcome between immediate and conventional loading of dental implants placed immediately after extraction in patients with a history of periodontal disease.Methods: Patients were randomly assigned to receive immediate implants with either immediate loading or conventional loading after 3 months. Both groups received a periodontal flap, tooth extraction, implant placement, allograft bone, and membrane placement. The immediate loading group received a temporary crown. In the conventional loading group primary closure was achieved. All patients were followed up at 3, 6, 12, and 24 months. Evaluation included radiographic bone changes, papillary esthetic outcome, and implant survival rate.Results: Seventy‐two patients were recruited into the study. However, 60 patients received immediate implant placement after extraction: 30 with conventional loading and 30 with immediate loading. In the immediate loading group the implant survival rate at 2 years was 96.7%, and the mean bone gain was 1.19 mm. The corresponding figures in the conventional loading group were 93.3% and 1 mm. The gain in bone level occurred mainly from baseline to 1 year postoperatively in both groups (P <0.001). The papilla index decreased from baseline to 1 year in both groups (P <0.001) and changed only slightly thereafter. There were no significant differences between the two groups in the amount of bone gain or papilla index change during 2 years.Conclusions: Immediate loading of a single implant placed in a fresh extraction site in periodontally compromised patients resulted in similar bone gain and soft tissue esthetic outcomes compared to delayed loading. Primary closure and delayed loading to ensure bone regeneration around implants were not critical in this study.