bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Staphylococcus aureus leucine aminopeptidase is localized to the bacterial cytosol and demonstrates a broad substrate range that extends beyond leucine
Authors: Carroll Ronan K. , Veillard Florian , Gagne Danielle T. , Lindenmuth Jarrod M. , Poreba Marcin , Drag Marcin , Potempa Jan , Shaw Lindsey N. 
Published: December 2012

Abstract

Staphylococcus aureus is a potent pathogen of humans exhibiting a broad disease range, in part due to an extensive repertoire of secreted virulence factors, including proteases. Recently, we identified the first example of an intracellular protease (leucine aminopeptidase, LAP) that is required for virulence in S. aureus. Disruption of pepZ, the gene encoding LAP, had no affect on the growth rate of bacteria; however, in systemic and localized infection models the pepZ mutant had significantly attenuated virulence. Recently, a contradictory report was published suggesting that LAP is an extracellular enzyme and it is required for growth in S. aureus. Here, we investigate these results and confirm our previous findings that LAP is localized to the bacterial cytosol and is not required for growth. In addition, we conduct a biochemical investigation of purified recombinant LAP, identifying optimal conditions for enzymatic activity and substrate preference for hydrolysis. Our results show that LAP has a broad substrate range, including activity against the dipeptide cysteine-glycine, and that leucine is not the primary target of LAP.
High Temperature Tensile Properties of Equal Channel Angular Pressed Al-Zn-Mg-Cu Alloy
Authors: Tekeli Süleyman , Güral Ahmet 
Published: December 2012

AbstractIn this study, ultra fine-grained microstructure was produced in Al–Zn–Mg–Cu alloy by equal channel angular pressing (ECAP) at 200 °C and a pressing speed of 2 mm s−1 using route C. The microstructure of the specimens was characterized by transmission and scanning electron microscopes. The results showed that the mean grain size of the specimens effectively decreased with increasing pass number. That is, while the grain size of unECAPed specimen was 10 µm, this value decreased to 300 nm after 14 passes. High temperature tensile tests were carried out at a strain rate of 1 × 10− 2 and temperature of 250 °C in the specimens with different pass number. It was seen that the flow stress decreased and the elongation to failure significantly increased with increasing pass number. The highest elongation to failure value of 90% was obtained in the specimen after 14 passes.
Microstructural and Mechanical Properties of Er2O3-ZrO2 Ceramics with Different Er2O3 Contents
Authors: Tekeli Süleyman , Aktaş Bülent , Küçüktüvek Mustafa 
Published: December 2012

AbstractIn this study, the effect of erbium oxide (Er2O3) addition on the microstructure, sinterability and mechanical properties of cubic zirconia (c-ZrO2) was investigated. 0–15 wt% Er2O3 and c-ZrO2 powders were mixed by means of colloidal processing and the specimens were sintered at different temperatures for 1 hour. The XRD results showed the existence of cubic crystal structure in all specimens. The lattice parameter of the specimens decreased with increasing Er2O3 addition up to 10 wt% and remained unchanged after this amount. The grain size of the Er2O3 doped c-ZrO2 specimens dropped up to 5 wt% Er2O3 addition and stayed almost unchanged at higher Er2O3 contents. Both hardness and fracture toughness measurements were done using Vickers hardness tester. The fracture toughness values of the undoped, 1, 5, 10 and 15 wt% Er2O3 doped c-ZrO2specimens were found to be 1.64 MPam1/2, 1.77 MPam1/2, 2.06 MPam1/2, 2.57 MPam1/2 and 2.31 MPam1/2 respectively.
A Simple Method for Synthesis of PbS Nanoparticles Using 2-Mercaptoethanol as the Capping Agent
Authors: Nabiyouni Gholamreza , Boroojerdian Parviz , Hedayati Kambiz , Ghanbari Davood 
Published: December 2012

AbstractLead sulfide nanoparticles were synthesized at room temperature via a simple chemical reaction. In this synthesis, 2-mercaptoethanolwas used as the capping agent and sodium sulfide was used as a sulfur source. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-vis) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy Electron microscopy study showed that without using a capping agent the bulk PbS is obtained, while adding the mercaptoethanol leads to production of nanoparticles. We found that the electronic absorption spectra as well as the particle sizes depend on the used capping agents. Two exitonic peaks with a large blue shift were observed when mercaptoethanol was used.
Effect of Ag on the Hot Corrosion of NiAl Intermetallic Compound
Authors: Liu S.N. , Su W. , Lv W.Y. , Wei Z.F. , Zeng C.L. 
Published: December 2012

AbstractThe low ambient tensile ductility and inadequate high temperature strength and creep resistance have limited the applications of intermetallic compound NiAl as a structure material at high temperatures. A small addition of Ag could increase the strength of NiAl. In this study, hot corrosion behavior of NiAl and NiAl-Ag containing 1 and 5%Ag (in weight percent), respectively, in molten (Na,K)﻿2SO4 at 1173 K has been examined by thermogravimetry and physical analysis techniques. The experimental results indicated that the corrosion rates of NiAl and NiAl-Ag tended to increase with exposure time, accompanied with the formation of nodules. Fast localized corrosion is the typical feature of the corrosion of both NiAl and NiAl-Ag. The addition of Ag to NiAl accelerated its corrosion, with a higher corrosion rate observed for the 5%Ag addition. The two-phase microstructure of NiAl-Ag alloys accelerated the formation of nodules in the regions close to Ag phases.
Comparison between neurological examination and computerized test of attention for suspected ADHD: implications for assessment of a common childhood disability
Authors: Diamond Gary , Badir Moad , Sevilla Patty , Inbar Dov , Gadoth Natan 
Published: December 2012

AbstractThe aim of this study was to determine the role of the Test of Variables of Attention (TOVA), a computer-based continuous performance test (CPT), in assessing suspected attention-deficit/hyperactivity disorder (ADHD), a pervasive cause of disability in children and adolescents.One hundred and fifty children and adolescents referred to a community-hospital-based neurology clinic for suspected ADHD underwent a comprehensive clinical evaluation by a pediatric neurologist in addition to the TOVA test. Retrospective chart data were analyzed separately for children aged 6–12 years (n=101) and adolescents (13–18 years) (n=49). Parents and teachers completedThe correlation between the neurologist’s impression of the presence of attention deficit and the TOVA scores was good in the younger group (r=0.28, p≤0.001) and weaker in the older group (r=0.29, p≤0.05). On nonparametric analysis, the neurological evaluation did not distinguish between low and high TOVA scorers in the older group. The neurologist’s impression correlated more closely with the DSM-IV parents ratings (r=0.29, p≤0.01) than the teachers’ (r=0.08, p≤0.05).The TOVA correlated well with clinical assessment of ADHD and has added value in the evaluation of ADHD in adolescents, for whom standardized rating scales are lacking. In younger children, an experienced clinician can usually reach an accurate diagnosis based on accepted clinical criteria, including parent and teacher reports.
Protective role of ferulic acid on carbon tetrachloride-induced hyperlipidemia and histological alterations in experimental rats
Authors: Marimuthu Srinivasan , Adluri Ram Sudheer , Rajagopalan Rukkumani , Menon Venugopal Padmanabhan 
Published: December 2012

Abstract

Background: The present study aimed to evaluate the antihyperlipidemic effect of ferulic acid (FA) on carbon tetrachloride (CCl4)-treated rats.

Methods: Female albino rats of the Wistar strain were used in the present study. The rats were divided into four groups: groups 1 and 4 received physiological saline (3 mL/kg body weight/week) by subcutaneous injection, whereas groups 2 and 3 received a subcutaneous injection of CCl4 (3 mL/kg body weight/week) for a total period of 12 weeks. In addition, groups 3 and 4 were administered FA (20 mL/kg body weight) every day for the last 90 days.

Results: The results showed significantly (p≤0.05) elevated levels of cholesterol, triglycerides (TG), and free fatty acids (FFA) in the liver and kidney of CCl4-treated rats as compared with those of the controls. In addition, the levels of cholesterol, FFA, phospholipids (PL), and TG were elevated significantly in the circulation. Administration of FA effectively reduced these levels of lipids in the plasma, liver, and kidney of CCl4-treated rats. The PL level was significantly decreased in the liver and kidney of CCl4-treated rats and was positively modulated by FA treatment. Our histopathological observations were also in correlation with the biochemical parameters.

Conclusions: From the results obtained, we could conclude that FA effectively protects the system against hyperlipidemia and may be an effective therapeutic agent for the treatment of this disorder.
Degeneration and orbits of tuples and subgroups in an abelian group
Authors: Calvert Wesley , Dutta Kunal , Prasad Amritanshu 
Published: December 2012

Abstract.A tuple (or subgroup) in a group is said to degenerate to another if the latter is an endomorphic image of the former. In a countable reduced abelian group, it is shown that if tuples (or finite subgroups) degenerate to each other, then they lie in the same automorphism orbit. The proof is based on techniques that were developed by Kaplansky and Mackey in order to give an elegant proof of Ulm's theorem. Similar results hold for reduced countably-generated torsion modules over principal ideal domains. It is shown that the depth and the description of atoms of the resulting poset of orbits of tuples depend only on the Ulm invariants of the module in question (and not on the underlying ring). A complete description of the poset of orbits of elements in terms of the Ulm invariants of the module is given. The relationship between this description of orbits and a very different-looking one obtained by Dutta and Prasad for torsion modules of bounded order is explained.
Cybersecurity Policy-Making at the Local Government Level: An Analysis of Threats, Preparedness, and Bureaucratic Roadblocks to Success
Authors: Caruson Kiki , MacManus Susan A. , McPhee Brian D. 
Published: December 2012

Abstract
Cybersecurity is a serious and complex problem that is escalating at all levels, yet little research has examined the issue at the local government level. This probative study, based on an extensive e-survey of Florida county officials, focuses on: (1) the incidence of cyber attacks – type, source (internal vs. external), and severity (major, minor); (2) perceived threats to agency operations – internally and externally from utility and telecommunications companies, financial institutions, hospitals, and schools; (3) the current status of cybersecurity planning; (4) the urgency of unmet preparedness-related needs; and (5) the degree to which financial, personnel, and organizational roadblocks have deterred the development of comprehensive cybersecurity plans. Controls are made for agency size and type of position held. The study finds that the knowledge or awareness gap between IT professionals and generalist and specialist public administrators is even wider at the local than at the federal (or state) levels. Preparedness lags because of this knowledge gap. There is little sense of urgency, partially because many non-IT officials have little understanding of newer, more dangerous cyber threats and cyber crime.
Limited-angle cone-beam computed tomography image
reconstruction by total variation minimization and piecewise-constant modification
Authors: Zeng Li , Guo Jiqiang , Liu Baodong 
Published: December 2012

Abstract.
Because of x-ray dose considerations or practical
mechanical restrictions, it may be interesting for some applications to
perform limited-angle scanning. So the limited-angle problem is of practical
significance in computed tomography (CT). Furthermore, it is an ill-posed
problem. Total variation minimization (TVM) and projection on convex sets
(POCS) based iterative reconstruction algorithm is comparatively valid for
this undersampling CT reconstruction problem and can obtain comparatively
good performance. But the reconstruction images have artifacts with gradual
change gray nearby edges. In this paper, a simple but efficient method to
eliminate such artifacts during the reconstruction is proposed. Based on the
same assumption of the TVM algorithm, for the object whose density distribution
is approximate piecewise-constant, we develop and investigate an
improved iterative reconstruction algorithm for volume image reconstruction
from limited-angle cone-beam scan, which is referred to as
piecewise-constant modification TVM-POCS (PM-TVM-POCS) algorithm. The grays
of voxels with gradually changed gray artifacts are modified in the TVM-POCS
iteration process by the piecewise-constant modification algorithm which is
regarded as a “collapse” process, and gradually approaches the true
piecewise-constant image. The results of simulation experiments show that
the presented modification algorithm can improve the quality of the
reconstructed image obviously and it is steady to noise. This modification
algorithm can also be applied to other reconstruction problems which have
artifacts with gradual change gray.
Material parameter estimation and hypothesis testing on a 1D viscoelastic stenosis model: Methodology
Authors: Banks H. Thomas , Hu Shuhua , Kenz Zackary R. , Kruse Carola , Shaw Simon , Whiteman John R. , Brewin Mark P. , Greenwald Steve E. , Birch Malcolm J. 
Published: December 2012

Abstract.
Non-invasive detection, localization and characterization of an arterial stenosis (a blockage or partial blockage in the artery) continues to be an important problem in medicine. Partial blockage stenoses are known to generate disturbances in blood flow which generate shear waves in the chest cavity. We examine a one-dimensional viscoelastic model that incorporates Kelvin–Voigt damping and internal variables, and develop a proof-of-concept methodology using simulated data. We first develop an estimation procedure for the material parameters. We use this procedure to determine confidence intervals for the estimated parameters, which indicates the efficacy of finding parameter estimates in practice. Confidence intervals are computed using asymptotic error theory as well as bootstrapping. We then develop a model comparison test to be used in determining if a particular data set came from a low input amplitude or a high input amplitude; this we anticipate will aid in determining when stenosis is present. These two thrusts together will serve as the methodological basis for our continuing analysis using experimental data currently being collected.
Mode of delivery in a subsequent pregnancy following previous instrumental delivery
Authors: Lurie Samuel , Steinberg Netanel , Tannus Samer , Golan Abraham , Sadan Oscar 
Published: December 2012

Abstract

Objective: To assess mode of subsequent delivery in women with previous instrumental vaginal delivery.

Study design: In this retrospective longitudinal study we followed women who underwent instrumental delivery. The study group included all consecutive parturient women who underwent an instrumental vaginal delivery during a 24-month period (1996–1999). We then identified women who had a subsequent delivery in our center until the end of the year 2010. The control group included women who had a spontaneous vaginal delivery from the same time.

Results: During the index period we had 349 consecutive successful instrumental vaginal deliveries. Of those, 125 women had a subsequent delivery in our center (35.8%). In subsequent pregnancies, the spontaneous vaginal delivery rate was 76.8% and 90.4%; the instrumental delivery rate was 8.8% and 1.6%; and the cesarean rate was 14.4% and 8.0%, in the instrumental delivery, and spontaneous vaginal delivery groups, respectively (P<0.05). The odds ratio for a woman to undergo either an instrumental delivery or a cesarean after having an instrumental delivery in a previous pregnancy was 2.8 (95% confidence interval 1.4–5.9, P<0.05).

Conclusion: Women with a previous instrumental delivery are at an increased risk of requiring either an instrumental delivery or a cesarean section in a subsequent pregnancy compared with women with a previous spontaneous vaginal delivery.
Prenatal maternal stress predicts cord-blood ferritin concentration
Authors: Armony-Sivan Rinat , Aviner Shraga , Cojocaru Lutzy , Fytlovitch Shlomo , Ben-Alon Dora , Eliassy Anat , Babkoff Harvey , Lozoff Betsy , Anteby Eyal 
Published: December 2012

Abstract

Aim: To examine the relationship between maternal stress in early pregnancy and cord-blood ferritin concentration.

Methods: The sample consisted of 140 pregnant women who lived in a region that was under rocket attack during a military operation (December 2008 to January 2009). Mothers in the stress group (n=63) were in their first trimester during this period. Mothers in the control group (n=77) became pregnant 4–5 months after the attacks ended. Maternal subjective stress was reported retrospectively. Cord-blood ferritin concentration was compared between stress and control groups, and was the dependent variable in a hierarchical multiple regression analysis.

Results: The mean cord-blood ferritin concentration was lower in the stress group compared to the control group (145.7±62.0 vs. 169.3±85.4 ng/mL, P<0.05). The cumulative distribution of cord-blood ferritin showed a shift to the left for the stress group. Hierarchical multiple regression analysis revealed that maternal subjective stress was a predictor for cord-blood ferritin concentration (hierarchical regression: β=–0.18, P<0.05), especially in the stress group (simple slope analysis: β=–0.32, P<0.01).

Conclusion: Maternal stress during the first trimester of pregnancy is associated with lower cord-blood ferritin concentration.
Expectant management in type II selective intrauterine growth restriction and abnormal chord insertion in monochorionic twins
Authors: Visentin Silvia , Macchi Veronica , Grumolato Francesca , Porzionato Andrea , De Caro Raffaele , Cosmi Erich 
Published: December 2012

Abstract

Objective: To assess perinatal outcome in type II monochorionic (MC) diamniotic twin pregnancies (DA) affected by selective intrauterine growth restriction (sIUGR) and abnormal cord insertion managed expectantly.

Methods: A prospective longitudinal study from June 2008 and July 2011 on 24 MCDA sIUGR twins. sIUGR was defined as estimated fetal weight below the 10th percentile in one twin and was classified into three groups based on umbilical artery (UA) Doppler diastolic flow (I: presence; II: constantly absent/reverse (AEDF/ARED); III: intermittently absent or reverse). Marginal cord insertion was defined as insertion within 2 cm of the placental disc edge, and velamentous insertion as a cord insertion into the fetal membranes. Expectant management was chosen in these twins, and absent or reverse A wave in the ductus venosus (DV) was a criterion for delivery. Neonatal outcome was available for all twins delivered. Pathological examination and vascular cast of placentas were performed in all cases.

Results: Fourteen twin pregnancies were type II sIUGR, and ten presented an abnormal umbilical cord insertion. Median gestational age (GA) at diagnosis of sIUGR was 18 weeks’ gestation (range 16–20 weeks), and all sIUGR co-twins showed AEDF of UA at a median gestational age of 20 weeks (range 18–22 weeks). Median gestational age at delivery was 30 weeks (range 28–34 weeks) with a median birth weight of 1285 g (range 307–1725 g). pH at birth and base excess (BE) were normal in all IUGR co-twin (pH>7.10, median BE 5.5); Apgar score at 5 min was >7. Perinatal outcome was favorable in all cases. Placental pathological examination confirmed the marginal insertion of the umbilical cord and the absence of anastomosis between the two portions of umbilical insertion.

Conclusions: This study highlights that expectant management for sIUGR type II twins with or without an abnormal cord insertion should be a valid option to time delivery for these fetuses as shown by the favorable neonatal outcome.
Hyperoxic resuscitation after hypoxia-ischemia induces cerebral inflammation that is attenuated by tempol in a reporter mouse model with very young mice
Authors: Døhlen Gaute , Antal Ellen-Ann , Castellheim Albert , Thaulow Erik , Kielland Anders , Saugstad Ola Didrik 
Published: December 2012

Abstract

Background: Oxygen supplementation is still part of international resuscitation protocols for premature children. Mechanisms for tissue damage by hypoxia/ischemia in the extreme premature involve inflammation.

Aim and method: To study cerebral inflammation after hypoxia/ischemia and oxygen treatment in the premature, we measured NF-κB activity in 5-day-old transgenic reporter mice in response to experimental hypoxia/ischemia. Results were correlated to cerebral histological evaluation and plasma cytokine levels. A treatment strategy with the antioxidant tempol was tested.

Results: One day after hypoxia/ischemia NF-κB activation was increased compared to controls [mean difference: 10.6±4.6% (P=0.03)]. Exposure to 100% oxygen after hypoxia/ischemia further increased NF-κB activation compared to hypoxia/ischemia alone [mean difference: 15.0±5.5% (P=0.01)]. Histological changes in the brain were positively correlated with NF-κB activity (P<0.001), but we found no significant difference in tissue damage between resuscitation with air and resuscitation with pure oxygen. Administration of tempol reduced NF-κB activation [mean difference: 14.6±5.0% (P=0.01)] and the plasma level of cytokines; however, the histological damage score was not affected.

Conclusion: Cerebral inflammatory response after hypoxia/ischemia in a mouse model with immature brain development corresponding to human prematurity prior to 32 weeks’ gestation was influenced by administration of oxygen. Tempol treatment attenuated inflammation but did not reduce the extent of histological cerebral damage.
Puerperal curettage after cesarean section delivery
Authors: Almansa Cristina , Camaño Isabel , Villar Olga , Montañez Dolores , Vallejo Paloma , García-Burguillo Antonio 
Published: December 2012

Abstract

Objective: To analyze the clinical situations that leads us to carry out curettage after cesarean section, the ultrasound prior surgery, intraoperative, and pathological findings.

Methods: A retrospective study of all cases of postpartum curettage after cesarean section in a level 3 maternity unit.

Results: There were 42 curettages to women with cesarean sections (1.6% of all cesarean sections). The indications for curettage were: fever: 21, methrorraghia: 11, and residual trophoblastic tissue: 10. In the previous ultrasound, all indicated curettages for retained trophoblastic tissue showed it, and in a lower proportion those indicated for fever (66.6%) or methrorraghia (22.2%). A total of fourteen curettages (35%) were performed without suspect image of retained tissue, and in all cases the surgeon described to obtain small amount of tissue. From material submitted to pathologic evaluation trophoblastic tissue was found in 64.7%, and there were no differences as curettage indication.

Conclusions: When the previous ultrasound do not showed retained tissue, the surgeon did not remove retained material. When extracted there were always in small amounts. Therefore, it could be concluded that after cesarean section the curettage should be indicated only in the presence of evident ultrasound image of retained products.