bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fractional Calcium Absorption Is Increased in Girls with Rett Syndrome
Authors: Motil Kathleen J. , Schultz Rebecca J. , Abrams Steven , Ellis Kenneth J. , Glaze Daniel G. 
Published: April 2006

ABSTRACTBackground:Rett syndrome (RTT), an X‐linked neurodevelopmental disorder primarilyaffecting girls, is characterized in part by osteopenia and increased risk of skeletal fractures. We hypothesized that decreased intestinal calcium (Ca) absorption relative to dietary Ca intake and increased renal Ca excretion might cause these problems in RTT.Objective:We measured fractional Ca absorption, urinary Ca loss, dietary Ca intake, and the hormonal factors regulating Ca metabolism to determine whether abnormalities in Ca balance might relate to poor bone mineralization in RTT girls and to evaluate the contribution of these factors to the overall dietary Ca needs of RTT girls.Study Design:Ten RTT girls and 10 controls, matched for age, sex, and pubertal status, were given a 3 day constant Ca diet that mimicked their habitual intakes. At the end of each dietary period, girls received single doses of 42Ca (intravenous) and 46Ca (oral). Fractional urinary excretion of 42Ca, 46Ca, 24 hour urinary Ca, and urinary cortisol excretion were determined. Serum Ca, phosphorous, alkaline phosphatase, vitamin D metabolites, parathyroid hormone (PTH), and osteocalcin were measured in the postabsorptive state. Bone mineral content (BMC) was measured by dual‐energy x‐ray absorptiometry.Results:Fractional Ca absorption was significantly higher in RTT than in control girls (mean ± SDp, 52 vs. 33 ± 13%). Dietary Ca intake (mean ± SDp, 1,100 vs. 1,446 ± 440 g/d) and net Ca absorption (mean ± SDp, 513 vs. 362 ± 306 mg/d) did not differ significantly between RTT and controls, respectively. Although urinary Ca excretion did not differ between groups, the increased urinary Ca:creatinine ratio (mean ± SDp, 0.39 vs. 0.23 ± 0.38) was consistent with clinical hypercalcuria and paralleled the significantly increased urinary cortisol excretion (mean ± SDp, 3.1 vs. 1.7 ± 1.1 mg/kg lean body mass per day) in the RTT girls. BMC was significantly lower in RTT than in controls (mean ± SDp, 527 vs. 860 ± 275 g). Serum Ca, P, alkaline phosphatase, vitamin D metabolites, PTH, and osteocalcin concentrations did not differ between the groups.Conclusion:Fractional Ca absorption showed a compensatory increase in the presence of adequate dietary Ca intakes, mild hypercalcuria, and pronounced bone mineral deficits in RTT girls. Whether supplemental dietary Ca could enhance fractional Ca absorption and improve bone mineralization in RTT girls is unknown.
Natural History and Symptomatology of Helicobacter pylori in Childhood and Factors Determining the Epidemiology of Infection
Authors: Özen Ahmet , Ertem Deniz , Pehlivanoglu Ender 
Published: April 2006

AbstractBackground:High seroprevalence rates for Helicobacter pylori have been reported in developing countries, yet few studies exist determining the pattern of change in the epidemiology of H. pylori infection in children. The knowledge of acquisition and loss rates of H. pylori and the relevance to the sociodemographic properties and the symptomatology of infection may provide clues for lifestyle changes that might protect children from infection, and also, it may provide rationale for eradication, screening, and protection policies. Our aim was to conduct a prospective study to elucidate the outcome, rate of acquisition, and loss of H. pylori infection in a population of healthy children.Methods:This study is based on follow‐up of 327 healthy Turkish children aged 3 to 12 years. The follow‐up was conducted 6 years after the baseline examination. Helicobacter pylori status was determined by 13C‐urea breath test. Children were investigated for sociodemographic variables and several symptoms.Results:Data from 136 (41%) of 327 children were available. The prevalence of infection increased from 52.9% to 56.6%, mainly increasing in children younger than 10 years. The incidence of H. pylori infection among previously uninfected children was 14%, and the loss rate of infection among previously infected children was 5.5% during the follow‐up. Socioeconomic status, household density, and antibiotic use during last 6 months were inversely related to H. pylori prevalence. Children infected with H. pylori were complaining more often of headache but not of abdominal pain or dyspepsia.Conclusions:In this study, the acquisition rate of H. pylori infection was 2.5‐fold higher than the loss of infection, and the acquisition mostly occurred before 10 years of age. Data regarding acquisition and loss of H. pylori infection are critical for understanding the epidemiology of infection and development of preventive and treatment strategies.
Antibiofilm Activity of GlmU Enzyme Inhibitors against Catheter-Associated Uropathogens
Authors: Burton Euan , Gawande Purushottam V. , Yakandawala Nandadeva , LoVetri Karen , Zhanel George G. , Romeo Tony , Friesen Albert D. , Madhyastha Srinivasa 
Published: April 2006

ABSTRACT

The colonization of uropathogenic bacteria on urinary catheters resulting in biofilm formation frequently leads to the infection of surrounding tissue and often requires removal of the catheter. Infections associated with biofilms are difficult to treat since they may be more than 1,000 times more resistant to antibiotics than their planktonic counterparts. We have developed an antibiofilm composition comprising an
N
-acetyl-
d
-glucosamine-1-phosphate acetyltransferase (GlmU) inhibitor and protamine sulfate, a cationic polypeptide. The antibiofilm activity of GlmU inhibitors, such as iodoacetamide (IDA),
N
-ethyl maleimide (NEM), and NEM analogs, including
N
-phenyl maleimide,
N
,
N
′-(1,2-phenylene)dimaleimide (oPDM), and
N
-(1-pyrenyl)maleimide (PyrM), was tested against that of catheter-associated uropathogens. Both IDA and NEM inhibited biofilm formation in
Escherichia coli
. All NEM analogs showed antibiofilm activity against clinical isolates of
E. coli
,
Pseudomonas aeruginosa
,
Klebsiella pneumoniae
,
Staphylococcus epidermidis
, and
Enterococcus faecalis
. The combination of oPDM with protamine sulfate (PS) enhanced its antibiofilm activity and reduced its effective concentration to as low as 12.5 μM. In addition, we found that the in vitro inhibitory activity of oPDM-plus-PS-coated silicone catheters against
P. aeruginosa
and
S. epidermidis
colonization was superior to that of catheters coated with silver hydrogel. Confocal scanning laser microscopy further confirmed that the oPDM-plus-PS-coated silicone catheters were almost free from bacterial colonization. Thus, a broad-spectrum antibiofilm composition comprising a GlmU inhibitor and protamine sulfate shows promise for use in anti-infective coatings for medical devices, including urinary catheters.
Streptococcus pneumoniae
Isolates Resistant to Telithromycin
Authors: Rantala M. , Haanperä-Heikkinen M. , Lindgren M. , Seppälä H. , Huovinen P. , Jalava J. ,   the Finnish Study Group for Antimicrobial Resistance
Published: April 2006

ABSTRACT

The telithromycin susceptibility of 210 erythromycin-resistant pneumococci was tested with the agar diffusion method. Twenty-six
erm
(B)-positive isolates showed heterogeneous resistance to telithromycin, which was manifested by the presence of colonies inside the inhibition zone. When these cells were cultured and tested, they showed stable, homogeneous, and high-level resistance to telithromycin.
Macrolide-Resistant
Streptococcus pyogenes
in Norway: Population Structure and Resistance Determinants
Authors: Littauer P. , Caugant D. A. , Sangvik M. , Høiby E. A. , Sundsfjord A. , Simonsen G. S. ,   the Norwegian Macrolide Study Group
Published: April 2006

ABSTRACT

A 2.7% prevalence of macrolide resistance in 1,657 Norwegian clinical
Streptococcus pyogenes
isolates was primarily due to
erm
(TR) (59%) and
mef
(A) (20%). Four clonal complexes comprised 75% of the strains. Macrolide resistance in
S. pyogenes
in Norway is imported as resistant strains or locally selected in internationally disseminated susceptible clones.
Different Domains of CD81 Mediate Distinct Stages of Hepatitis C Virus Pseudoparticle Entry
Authors: Bertaux Claire , Dragic Tatjana 
Published: April 2006

ABSTRACT
The CD81 tetraspanin was first identified as a hepatitis C virus (HCV) receptor by its ability to bind the soluble ectodomain of envelope glycoprotein E2 (sE2). More recently, it has been suggested that CD81 is necessary but not sufficient for HCV entry into target cells. Here we present further evidence that putative human hepatocyte-specific factors act in concert with CD81 to mediate sE2 binding and HCV pseudoparticle (HCVpp) entry. Moreover, we show that CD81-mediated HCVpp entry entails E2 binding to residues in the large extracellular loop as well as molecular events mediated by the transmembrane and intracellular domains of CD81. The concept that CD81 receptor function progresses in stages is further supported by our finding that anti-CD81 monoclonal antibodies inhibit HCVpp entry by different mechanisms. The half-life of CD81-HCVpp binding was determined to be approximately 17 min, and we propose that binding is followed by CD81 oligomerization, partitioning into cholesterol-rich membrane domains, or other, lateral protein-protein interactions. This results in the formation of a receptor-virus complex that undergoes endocytosis and pH-dependent membrane fusion.
Cellular Splicing and Transcription Regulatory Protein p32 Represses Adenovirus Major Late Transcription and Causes Hyperphosphorylation of RNA Polymerase II
Authors: Öhrmalm Christina , Akusjärvi Göran 
Published: April 2006

ABSTRACT
The cellular protein p32 is a multifunctional protein, which has been shown to interact with a large number of cellular and viral proteins and to regulate several important activities like transcription and RNA splicing. We have previously shown that p32 regulates RNA splicing by binding and inhibiting the essential SR protein ASF/SF2. To determine whether p32 also functions as a regulator of splicing in virus-infected cells, we constructed a recombinant adenovirus expressing p32 under the transcriptional control of an inducible promoter. Much to our surprise the results showed that p32 overexpression effectively blocked mRNA and protein expression from the adenovirus major late transcription unit (MLTU). Interestingly, the p32-mediated inhibition of MLTU transcription was accompanied by an approximately 4.5-fold increase in Ser 5 phosphorylation and an approximately 2-fold increase in Ser 2 phosphorylation of the carboxy-terminal domain (CTD). Further, in p32-overexpressing cells the efficiency of RNA polymerase elongation was reduced approximately twofold, resulting in a decrease in the number of polymerase molecules that reached the end of the major late L1 transcription unit. We further show that p32 stimulates CTD phosphorylation in vitro. The inhibitory effect of p32 on MLTU transcription appears to require the CAAT box element in the major late promoter, suggesting that p32 may become tethered to the MLTU via an interaction with the CAAT box binding transcription factor.
On Improving 4-km Mesoscale Model Simulations
Authors: Deng Aijun , Stauffer David R. 
Published: April 2006

Abstract
A previous study showed that use of analysis-nudging four-dimensional data assimilation (FDDA) and improved physics in the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) produced the best overall performance on a 12-km-domain simulation, based on the 18–19 September 1983 Cross-Appalachian Tracer Experiment (CAPTEX) case. However, reducing the simulated grid length to 4 km had detrimental effects. The primary cause was likely the explicit representation of convection accompanying a cold-frontal system. Because no convective parameterization scheme (CPS) was used, the convective updrafts were forced on coarser-than-realistic scales, and the rainfall and the atmospheric response to the convection were too strong. The evaporative cooling and downdrafts were too vigorous, causing widespread disruption of the low-level winds and spurious advection of the simulated tracer. In this study, a series of experiments was designed to address this general problem involving 4-km model precipitation and gridpoint storms and associated model sensitivities to the use of FDDA, planetary boundary layer (PBL) turbulence physics, grid-explicit microphysics, a CPS, and enhanced horizontal diffusion. Some of the conclusions include the following: 1) Enhanced parameterized vertical mixing in the turbulent kinetic energy (TKE) turbulence scheme has shown marked improvements in the simulated fields. 2) Use of a CPS on the 4-km grid improved the precipitation and low-level wind results. 3) Use of the Hong and Pan Medium-Range Forecast PBL scheme showed larger model errors within the PBL and a clear tendency to predict much deeper PBL heights than the TKE scheme. 4) Combining observation-nudging FDDA with a CPS produced the best overall simulations. 5) Finer horizontal resolution does not always produce better simulations, especially in convectively unstable environments, and a new CPS suitable for 4-km resolution is needed. 6) Although use of current CPSs may violate their underlying assumptions related to the size of the convective element relative to the grid size, the gridpoint storm problem was greatly reduced by applying a CPS to the 4-km grid.
Rain Retrieval from TMI Brightness Temperature Measurements Using a TRMM PR–Based Database
Authors: Viltard Nicolas , Burlaud Corinne , Kummerow Christian D. 
Published: April 2006

Abstract
This study focuses on improving the retrieval of rain from measured microwave brightness temperatures and the capability of the retrieved field to represent the mesoscale structure of a small intense hurricane. For this study, a database is constructed from collocated Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and the TRMM Microwave Imager (TMI) data resulting in about 50 000 brightness temperature vectors associated with their corresponding rain-rate profiles. The database is then divided in two: a retrieval database of about 35 000 rain profiles and a test database of about 25 000 rain profiles. Although in principle this approach is used to build a database over both land and ocean, the results presented here are only given for ocean surfaces, for which the conditions for the retrieval are optimal. An algorithm is built using the retrieval database. This algorithm is then used on the test database, and results show that the error can be constrained to reasonable levels for most of the observed rain ranges. The relative error is nonetheless sensitive to the rain rate, with maximum errors at the low and high ends of the rain intensities (+60% and −30%, respectively) and a minimum error between 1 and 7 mm h−1. The retrieval method is optimized to exhibit a low total bias for climatological purposes and thus shows a high standard deviation on point-to-point comparisons. The algorithm is applied to the case of Hurricane Bret (1999). The retrieved rain field is analyzed in terms of structure and intensity and is then compared with the TRMM PR original rain field. The results show that the mesoscale structures are indeed well reproduced even if the retrieved rain misses the highest peaks of precipitation. Nevertheless, the mesoscale asymmetries are well reproduced and the maximum rain is found in the correct quadrant. Once again, the total bias is low, which allows for future calculation of the heat sources/sinks associated with precipitation production and evaporation.
Correcting Active Scatterometer Data for the Effects of Rain Using Passive Radiometer Data
Authors: Hilburn K. A. , Wentz F. J. , Smith D. K. , Ashcroft P. D. 
Published: April 2006

Abstract
A model for the effects of rain on scatterometer data is proposed. Data from the Advanced Microwave Scanning Radiometer (AMSR) and the SeaWinds scatterometer, both on the Midori-II satellite, are used. The model includes three basic rain effects: attenuation, rain roughening of the sea surface, and volumetric backscatter. Attenuation is calculated directly from the radiometer data and beam filling is explicitly addressed. The model simultaneously solves for both the rain roughening and volumetric backscatter. Fitting the coefficients of the model requires an estimate of the radar cross section because of wind roughening, and NCEP Global Data Assimilation System (GDAS) wind vectors are used for this purpose. Both the derived rain roughening and volumetric backscatter are similar to results in published work, but the values are slightly smaller, especially for vertical polarization. Drop size distribution variability is accounted for by formulating the radar equation in terms of the parameters of the radiative transfer equation and using additional radiometric information. Explicit inclusion of vertical profile variability results in an underdetermined problem, but it is implicitly included in fitting the model to the data. The correction makes large improvements in wind speeds and modest improvements in wind directions. Wind statistics and specific examples are shown to illustrate the nature of the improvements. The correction is limited, however, by measurement mismatch issues and the nonlinear nature of the wind retrieval.
Learning to mark: a qualitative study of the experiences and concerns of medical markers
Authors: Hawthorne Kamila , Wood Fiona , Hood Kerenza , Cannings-John Rebecca , Houston Helen 
Published: April 2006

Abstract

Background
Although there is published research on the methods markers use in marking various types of assessment, there is relatively little information on the processes markers use in approaching a marking exercise. This qualitative paper describes the preparation and experiences of general practice (GP) teachers who undertake marking a written assessment in an undergraduate medical course.

Methods
Semi-structured interviews were conducted with seven of the 16 GP tutors on an undergraduate course. The purposive sample comprised two new markers, two who had marked for a couple of years and three experienced markers. Each respondent was interviewed twice, once following a formative assessment of a written case study, and again after a summative assessment. All interviews were audio-taped and analysed for emerging themes. A respondent validation exercise was conducted with all 16 GP tutors.

Results
Markers had internal concerns about their ability to mark fairly and made considerable efforts to calibrate their marking. They needed guidance and coaching when marking for the first time and adopted a variety of marking styles, reaching a decision through a number of routes. Dealing with pass/fail borderline scripts and the consequences of the mark on the student were particular concerns. Even experienced markers felt the need to calibrate their marks both internally and externally

Conclusion
Previous experience of marking appears to improve markers' confidence and is a factor in determining the role which markers adopt. Confidence can be improved by giving clear instructions, along with examples of marking. The authors propose that one method of providing this support and coaching could be by a process of peer review of a selection of papers prior to the main marking. New markers in particular would benefit from further guidance, however they are influenced by others early on in their marking career and course organisers should be mindful of this when arranging double marking.
Maximization of the Chemiluminescence Efficiency of 1,4,5-Triarylhydroperoxy-4H-isoimidazoles
Authors: Kimura Masaru , Nishikawa Hideki , Kura Hisanori , Lim Hyung , White Emil H 
Published: April 2006

Abstract
A bell shape correlation curve has been found for a plot of the Hammett σ constant and the quantum yields of the formation of excited amidines from the chemiluminescent reaction of 2-(p-dimethylaminophenyl)-4,5-di(p-X–phenyl)-4-hydroperoxy-4H-isoimidazoles (X = OCH3, H, F, Cl, CF3, and CN) with bases.
Stereoselective Synthesis of O-(2-Azido-2-deoxy-α-D-galactopyranosyl)-L-serine and -L-threonine Derivatives by Using the Catalytic Amount of Active Acidic Species
Authors: Matsubara Koki , Mukaiyama Teruaki 
Published: April 2006

Abstract
In the presence of a catalytic amount of SnCl3(ClO4) or SiCl3(ClO4), O-(2-azido-2-deoxy-α-D-galactopyranosyl)-L-serine and -L-threonine are stereoselectively synthesized in excellent yields from 1-O-acetyl-2-azido-2-deoxy-3,4,6-tri-O-benzyl-D-galactopyranose and trimethylsilylated L-serine or L-threonine, respectively.
Novel Tetranuclear Nickel(II) Complex with a Mixed-Spin State Generated by Pairing of Dimers
Authors: Mikuriya Masahiro , Nakadera Keiichi , Kotera Takanori 
Published: April 2006

Abstract
A tetranuclear nickel(II) complex with 2,6-bis(salicylideneaminomethyl)-4-methylphenol (H3L), [Ni4(L)2(pz)2(CH3OH)] (pz = pyrazolate ion) has been synthesized and characterized by electronic spectra and magnetic susceptibilites (80–300 K). The X-ray crystal structure analysis has demonstrated that it consists of tetranuclear (low-spin–high-spin–high-spin–low-spin) molecules with a zigzag structure.
Trans → cis One-way Photoisomerization of an Olefin Substituted with an Indole and a Pyridine Ring. Effect of Intramolecular Hydrogen Bond
Authors: Arai Tatsuo , Iwasaki Takeshi , Tokumaru Katsumi 
Published: April 2006

Abstract
On direct irradiation in benzene 2-[2-(2-pyridyl)ethenyl]indole undegoes trans-to-cis one-way isomerization in the excited singlet state.
One-Way Photoisomerization of Dienes Substituted by an Anthracene Nucleus
Authors: Gong Yuefa , Arai Tatsuo , Tokumaru Katsumi 
Published: April 2006

Abstract
On benzil sensitization, 1-(2-anthryl)-1-cis,3-trans-pentadiene and cis-1-(2-anthryl)-4-methyl-1,3-pentadiene underwent one-way cis → trans isomerization with high quantum efficiencies in an adiabatic process at the excited triplet state.
Steady-State Flow Analysis. A New Approach to Rapid and Sensitive Analysis for Long-Period Reactions in Continuous-Flow System
Authors: Zhang Chongliang , Narusawa Yoshio , Kitahama Shizuo 
Published: April 2006

Abstract
Air-segmented flow analysis, flow-injection analysis and sequential-injection analysis which characterized with sample zone dispersion and/or sequentially, do not suit to an analysis for long-period reactions because of their sharp decreases in analytical speed and sensitivity. A new approach, based on the combined techniques of a parallel double-line FIA, a stopped-flow FIA and a steady-state determination model, is proposed to develop a rapid and sensitive method for filling a gap of the application to long-period reactions in the present continuous-flow analysis.
Preparation of Partially Protected Peptide Thioesters Containing a Cysteine Residue and Their Segment Condensation
Authors: Kwon Yeondae , Zhang Ruoheng , Bemquerer Marcelo P , Tominaga Mineko , Hojo Hironobu , Aimoto Saburo 
Published: April 2006

Abstract
Methods for the preparation of partially-protected cysteine-containing peptide segments were developed. The peptide thioester, obtained via a solid-phase method of Boc chemistry, was used for segment condensation with an amino component peptide in the presence of silver ions and N-hydroxysuccinimide to give a desired product in good yield.
One-pot Preparation of 2-Chloromethyldioxolanes and 2-Aminothiazoles from Chloromethyltrioxanes
Authors: Wakasugi Takashi , Miyakawa Tadashi , Suzuki Fukuichi , Itsuno Shinichi , Ito Koichi 
Published: April 2006

Abstract
Thermal degradation of chloromethyltrioxanes in the presence of catalytic amount of montmorillonite clay generated α-chloroaldehydes with high purity, which were treated in situ with ethylene glycol or thiourea to afford 2-chloromethyldioxolanes and 2-aminothiazoles, respectively. The clay catalysts used were removed by filtration.