bluuebunny/crossref_metadata_2025 huggingface dataset:
A Robust Method for Testing Association in Genome-Wide Association Studies
Authors: Chen Zhongxue , Ng Hon Keung Tony
Published: December 2011

In genetic association studies, due to the varying underlying genetic models, no single statistical test can be the most powerful test under all situations. Current studies show that if the underlying genetic models are known, trend-based tests, which outperform the classical Pearson χ2 test, can be constructed. However, when the underlying genetic models are unknown, the χ2 test is usually more robust than trend-based tests. In this paper, we propose a new association test based on a generalized genetic model, namely the generalized order-restricted relative risks model. Through a Monte Carlo simulation study, we show that the proposed association test is generally more powerful than the χ2 test, and more robust than those trend-based tests. The proposed methodologies are also illustrated by some real SNP datasets.
Acute Exposure to Low Glucose Rapidly Induces Endothelial Dysfunction and Mitochondrial Oxidative Stress
Authors: Wang Jingli , Alexanian Anna , Ying Rong , Kizhakekuttu Tinoy J. , Dharmashankar Kodlipet , Vasquez-Vivar Jeanette , Gutterman David D. , Widlansky Michael E.
Published: December 2011

Objective—

Hypoglycemia is associated with increased mortality. The reasons for this remain unclear, and the effects of low glucose exposure on vascular endothelial function remain largely unknown. We endeavored to determine the effects of low glucose on endothelial cells and intact human arterioles.

Methods and Results—

We exposed human umbilical vein endothelial cells to low glucose conditions in a clinically relevant range (40–70 mg/dL) and found rapid and marked reductions in nitric oxide (NO) bioavailability (
P
<0.001). This was associated with concomitantly increased mitochondrial superoxide production (
P
<0.001) and NO-dependent mitochondrial hyperpolarization (
P
<0.001). Reduced NO bioavailability was rapid and attributable to reduced endothelial nitric oxide synthase activity and destruction of NO. Low glucose rapidly activated AMP kinase, but physiological activation failed to restore NO bioavailability. Pharmacological AMP kinase activation led to phosphorylation of endothelial nitric oxide synthase's Ser633 activation site, reversing the adverse effects of low glucose. This protective effect was prevented by
l
-N
G
-Nitroarginine methyl ester. Intact human arterioles exposed to low glucose demonstrated marked endothelial dysfunction, which was prevented by either metformin or TEMPOL.

Conclusion—

Our data suggest that moderate low glucose exposure rapidly impairs NO bioavailability and endothelial function in the human endothelium and that pharmacological AMP kinase activation inhibit this effect in an NO-dependent manner.
Endogenous Estrogens Lower Plasma PCSK9 and LDL Cholesterol But Not Lp(a) or Bile Acid Synthesis in Women
Authors: Persson Lena , Henriksson Peter , Westerlund Eli , Hovatta Outi , Angelin Bo , Rudling Mats
Published: December 2011

Objective—

Cholesterol and lipoprotein metabolism display pronounced gender differences. Premenopausal women have lower LDL and higher HDL cholesterol, whereas men display higher synthetic rates of bile acids and cholesterol. The effects of the administration of exogenous hormones to humans and animals indicate that these gender differences can often be explained by estrogens. We evaluated how increased levels of endogenous estrogens modulate cholesterol and lipoprotein metabolism in women.

Methods and Results—

We studied healthy women during initiation of in vitro fertilization using blood samples obtained when endogenous estrogens were low and high. Cholesterol in VLDL and LDL, but not in HDL, was reduced 20% when estrogens were high. Apolipoprotein B levels decreased 13%. Apolipoprotein A-I and triglyceride levels increased 8% and 37%, respectively, whereas lipoprotein(a) levels were unchanged. Circulating PCSK9, a suppressor of LDL receptors, was reduced 14% when estrogens were high. Serum markers of bile acid and cholesterol synthesis were unaltered. Growth hormone levels increased 3-fold when estrogens were high, whereas insulin-like growth factor-1 and fibroblast growth factor-21 concentrations were unaltered.

Conclusion—

In women, Apolipoprotein B-containing particles and circulating PCSK9 are reduced when endogenous estrogens are high, indicating that endogenous estrogens induce hepatic LDL receptors partly through a posttranscriptional mechanism. However, estrogens do not stimulate bile acid or cholesterol synthesis.
Vascular Bioactivation of Nitroglycerin Is Catalyzed by Cytosolic Aldehyde Dehydrogenase-2
Authors: Beretta Matteo , Wölkart Gerald , Schernthaner Michaela , Griesberger Martina , Neubauer Regina , Schmidt Kurt , Sacherer Michael , Heinzel Frank R. , Kohlwein Sepp D. , Mayer Bernd
Published: December 2011

Rationale:

According to general view, aldehyde dehydrogenase-2 (ALDH2) catalyzes the high-affinity pathway of vascular nitroglycerin (GTN) bioactivation in smooth muscle mitochondria. Despite having wide implications to GTN pharmacology and raising many questions that are still unresolved, mitochondrial bioactivation of GTN in blood vessels is still lacking experimental support.

Objective:

In the present study, we investigated whether bioactivation of GTN is affected by the subcellular localization of ALDH2 using immortalized ALDH2-deficient aortic smooth muscle cells and mouse aortas with selective overexpression of the enzyme in either cytosol or mitochondria.

Methods and Results:

Quantitative Western blotting revealed that ALDH2 is mainly cytosolic in mouse aorta and human coronary arteries, with only approximately 15% (mouse) and approximately 5% (human) of the enzyme being localized in mitochondria. Infection of ALDH2-deficient aortic smooth muscle cells or isolated aortas with adenovirus containing ALDH2 cDNA with or without the mitochondrial signal peptide sequence led to selective expression of the protein in mitochondria and cytosol, respectively. Cytosolic overexpression of ALDH2 restored GTN-induced relaxation and GTN denitration to wild-type levels, whereas overexpression in mitochondria (6-fold vs wild-type) had no effect on relaxation. Overexpression of ALDH2 in the cytosol of ALDH2-deficient aortic smooth muscle cells led to a significant increase in GTN denitration and cyclic GMP accumulation, whereas mitochondrial overexpression had no effect.

Conclusions:

The data indicate that vascular bioactivation of GTN is catalyzed by cytosolic ALDH2. Mitochondrial GTN metabolism may contribute to oxidative stress-related adverse effects of nitrate therapy and the development of nitrate tolerance.
High-Mobility Group A1 Protein
Authors: Bloch Mandy , Prock André , Paonessa Francesco , Benz Verena , Bähr Ilse N. , Herbst Lena , Witt Henning , Kappert Kai , Spranger Joachim , Stawowy Philipp , Unger Thomas , Fusco Alfredo , Sedding Daniel , Brunetti Antonio , Foryst-Ludwig Anna , Kintscher Ulrich
Published: December 2011

Rationale:

The nuclear receptor peroxisome proliferator–activated receptor-γ (PPARγ) is an important regulator of gene transcription in vascular cells and mediates the vascular protection observed with antidiabetic glitazones.

Objective:

To determine the molecular mechanism of ligand-dependent transrepression in vascular smooth muscle cells and their impact on the vascular protective actions of PPARγ.

Methods and Results:

Here, we report a molecular pathway in vascular smooth muscle cells by which ligand-activated PPARγ represses transcriptional activation of the matrix-degrading matrix metalloproteinase-9 (MMP-9) gene, a crucial mediator of vascular injury. PPARγ-mediated transrepression of the MMP-9 gene was dependent on the presence of the high-mobility group A1 (HMGA1) protein, a gene highly expressed in vascular smooth muscle cells, newly identified by oligonucleotide array expression analysis. Transrepression of MMP-9 by PPARγ and regulation by HMGA1 required PPARγ SUMOylation at K367. This process was associated with formation of a complex between PPARγ, HMGA1, and the SUMO E2 ligase Ubc9 (ubiquitin-like protein SUMO-1 conjugating enzyme). After PPARγ ligand stimulation, HMGA1 and PPARγ were recruited to the MMP-9 promoter, which facilitated binding of SMRT (silencing mediator of retinoic acid and thyroid hormone receptor), a nuclear corepressor involved in transrepression. The relevance of HMGA1 for vascular PPARγ signaling was underlined by the complete absence of vascular protection through a PPARγ ligand in HMGA1
−/−
mice after arterial wire injury.

Conclusions:

The present data suggest that ligand-dependent formation of HMGA1-Ubc9-PPARγ complexes facilitates PPARγ SUMOylation, which results in the prevention of SMRT corepressor clearance and induction of MMP-9 transrepression. These data provide new information on PPARγ-dependent vascular transcriptional regulation and help us to understand the molecular consequences of therapeutic interventions with PPARγ ligands in the vasculature.
FRS2α-Mediated FGF Signals Suppress Premature Differentiation of Cardiac Stem Cells Through Regulating Autophagy Activity
Authors: Zhang Jue , Liu Junchen , Huang Yanqing , Chang Julia Y.F. , Liu Leyuan , McKeehan Wallace L. , Martin James F. , Wang Fen
Published: December 2011

Rationale:

Although the fibroblast growth factor (FGF) signaling axis plays important roles in heart development, the molecular mechanism by which the FGF regulates cardiogenesis is not fully understood.

Objective:

To investigate the mechanism by which FGF signaling regulates cardiac progenitor cell differentiation.

Methods and Results:

Using mice with tissue-specific ablation of FGF receptors and FGF receptor substrate 2
α
(
Frs2
α
) in heart progenitor cells, we demonstrate that disruption of FGF signaling leads to premature differentiation of cardiac progenitor cells in mice. Using embryoid body cultures of mouse embryonic stem cells, we reveal that FGF signaling promotes mesoderm differentiation in embryonic stem cells but inhibits cardiomyocyte differentiation of the mesoderm cells at later stages. Furthermore, we also report that inhibiting FRS2α-mediated signals increases autophagy and that activating autophagy promotes myocardial differentiation and vice versa.

Conclusions:

The results indicate that the FGF/FRS2α-mediated signals prevent premature differentiation of heart progenitor cells through suppressing autophagy. The findings provide the first evidence that autophagy plays a role in heart progenitor differentiation.
Sirolimus as Primary Immunosuppression Attenuates Allograft Vasculopathy With Improved Late Survival and Decreased Cardiac Events After Cardiac Transplantation
Authors: Topilsky Yan , Hasin Tal , Raichlin Eugenia , Boilson Barry A. , Schirger John A. , Pereira Naveen L. , Edwards Brooks S. , Clavell Alfredo L. , Rodeheffer Richard J. , Frantz Robert P. , Maltais Simon , Park Soon J. , Daly Richard C. , Lerman Amir , Kushwaha Sudhir S.
Published: December 2011

Background—

We retrospectively analyzed the potential of sirolimus as a primary immunosuppressant in the long-term attenuation of cardiac allograft vasculopathy progression and the effects on cardiac-related morbidity and mortality.

Methods and Results—

Forty-five cardiac transplant recipients were converted to sirolimus 1.2 years (0.2, 4.0) after transplantation with complete calcineurin inhibitor withdrawal. Fifty-eight control subjects 2.0 years (0.2, 6.5 years) from transplantation were maintained on calcineurin inhibitors. Age, sex, ejection fraction, and time from transplantation to baseline intravascular ultrasound study were not different (
P
>0.2 for all) between the groups; neither were secondary immunosuppressants and use of steroids. Three-dimensional intravascular ultrasound studies were performed at baseline and 3.1 years (1.3, 4.6 years) later. Plaque index progression (plaque volume/vessel volume) was attenuated in the sirolimus group (0.7±10.5% versus 9.3±10.8%;
P
=0.0003) owing to reduced plaque volume in patients converted to sirolimus early (<2 years) after transplantation (
P
=0.05) and improved positive vascular remodeling (
P
=0.01) in patients analyzed late (>2 years) after transplantation. Outcome analysis in 160 consecutive patients maintained on 1 therapy was performed regardless of performance of intravascular ultrasound examinations. Five-year survival was improved with sirolimus (97.4±1.8% versus 81.8±4.9%;
P
=0.006), as was freedom from cardiac-related events (93.6±3.2% versus 76.9±5.5%;
P
=0.002).

Conclusions—

Substituting calcineurin inhibitor with sirolimus as primary immunosuppressant attenuates long-term cardiac allograft vasculopathy progression and may improve long-term allograft survival owing to favorable coronary remodeling. Because of the lack of randomization and retrospective nature of our analysis, the differences in outcome should be interpreted cautiously, and prospective clinical trials are required.
Insufficient Platelet Inhibition Is Related to Silent Embolic Cerebral Infarctions After Coronary Angiography
Authors: Kim Bum Joon , Lee Seung-Whan , Park Seong-Wook , Kang Dong-Wha , Kim Jong S. , Kwon Sun U.
Published: December 2011

Background and Purpose—

Considering that insufficient platelet inhibition is related to thrombotic complications after coronary angiography, we hypothesized that the extent of platelet inhibition by antiplatelet agents is related to the occurrence of silent embolic cerebral infarction (SECI) after coronary angiography.

Methods—

Among the patients scheduled for coronary artery bypass surgery, we retrospectively analyzed the location of SECI on diffusion-weighted imaging of 272 patients, which was performed after coronary angiography, as a presurgical evaluation in Phase 1 study. In Phase 2 study, we have prospectively recruited 102 patients to compare the extent of platelet inhibition measured by the VerifyNow system among patients with and without SECI.

Results—

SECI is observed in 45 patients (16.5%) in Phase 1 and 17 (16.7%) in Phase 2. The lesions were slightly more frequent in the right hemisphere. In the Phase 2 study, aspirin reaction units and P
2
Y
12
reaction units were higher in the patients with SECI than those without (aspirin reaction units: 490±72 versus 446±53,
P
=0.03; P
2
Y
12
reaction units: 352±65 versus 300±77,
P
=0.009). The incidence of SECI increased with the number of resistant antiplatelets; resistance to both antiplatelet agent (50%), resistance to 1 antiplatelet agent (22%), and no resistance (4%;
P
=0.023). From the result of logistic regression, higher aspirin reaction units, white blood cell count, low hemoglobin, and nonresponsiveness to antiplatelet agents were independent risk factors.

Conclusions—

Insufficient platelet inhibition after administration of antiplatelet agents is related with SECI appearing after coronary angiography.
Rinman, Diderot, and Lavoisier: New Evidence Regarding Guillaume Franois Rouelle's Private Laboratory and Chemistry Course
Authors: Beretta Marco
Published: December 2011

This paper will present two recently discovered documents that shed light on the activities of the French chemist Guillaume Franois Rouelle.In 1746 the Swedish chemist and mineralogist Sven Rinman visited the private chemistry laboratory recently set up by Rouelle in Paris, and he has left us a record of this visit, including some rare sketches. Given the crucial contribution made by Rouelle's laboratory to the development of the science of chemistry in 18th-century Europe, Rinman's description is reproduced here in full.Rouelle also taught an extremely popular chemistry course at the Jardin des Plantes in Paris, and conserved in the archives of Antoine Laurent Lavoisier are some notes taken by Denis Diderot in 1757 which demonstrate that for a period the prominent Enlightenment figure attended these lectures regularly.
Open Skies in turbulence, a well functioning treaty is endangered by outside developments
Authors: Spitzer Hartwig
Published: December 2011

Today the Treaty on Open Skies is confronted with contradictory developments: Continuing adherence of all parties, in particular Russia and the United States to the treaty and preparations for modernisation of the technical monitoring capabilities on the one hand, while the general support for conventional arms control and military confidence building in the OSCE region declines. Since January 2011 an intervention of Turkey over the accession application of Cyprus has prevented any regular sessions and decisions of the Open Skies Consultative Commission ( OSCC ). The treaty is taken hostage for an unsolved status conflict which has much wider dimensions. Since the impasse in the OSCC could not be solved on the diplomatic level so far (Oct. 2011), high level political intervention is needed to save the treaty from erosion.
Diplomacy and life on Georgia's boundary line
Authors: van Peski Caecilia J.
Published: December 2011

On the third anniversary of the war over South Ossetia, resumed talks between Georgia and Russia are needed to create positive momentum in a still unstable environment. The article examines the continuing strains and recommends that the two sides engage in direct dialogue in order to de-escalate allegations about the other's involvement in the conflict. While formal diplomatic relations remain more or less suspended, many mutual interests remain. Paramount in this is the fact that Georgia and Russia share interests in improving mutual security, trade and transport.

The impact of the ongoing conflict on Georgia's very diverse communities differs substantially, as do their priorities. Concerns over the future amongst these communities are widespread. The consequences of the violence and subsequent failure to progress resolution of the conflict still affect communities, especially those living along the Administrative Boundary Line between South Ossetia and Georgia proper. Although no major incidents of violence have occurred since 2008 and the level of humanitarian assistance provided to communities around the ABL has been impressive during the first two years following the war, the contact and movement across the ABL has become increasingly difficult, badly affecting those dependent on cross-border interaction for their personal wellbeing and that of their communities. As a result, a range of vulnerabilities is more likely to come to the surface and undermine the future sustainability of communities living along the ABL.

As such, it is essential that local and international actors, including OSCE and EUMM are better able to distinguish between the varied needs of communities living along the ABL , in order to develop appropriate strategies for responding to them.
Reviewing the OSCE Human Dimension events
Authors: Greminger Thomas
Published: December 2011

Many voices asking for a review of OSCE Human Dimension events have been heard. This year an increased interest among participating states in reviewing and improving the organization and modalities of the Human Dimension meetings was noticed. The Chair of the Human Dimension Committee, the Swiss Ambassador, Thomas Greminger, has, together with the Lithuanian chairmanship, decided to put this topic on the agenda. In order to support the discussions on this 'difficult' topic in an objective way, a study is currently prepared by an independent Swiss think-tank. While this process will not be an easy task, Ambassador Greminger is committed to leading it through in a transparent and inclusive manner.
Tactical Nuclear Weapons
Authors: Zagorski Andrei
Published: December 2011

Russia and the US have significantly reduced their tactical nuclear weapons over the past twenty years. The remaining weapons have been moved from active service and stored separate from their delivery systems. However, both still keep tactical nuclear weapons available for eventual deployment, and Moscow maintains not only a larger but also a much more diverse stockpile of such weapons than the US. The prospects for designing an arms control regime covering TNW are complicated by a series of factors. Technically, verifying any limitations or reductions of non-deployed weapons is an extremely sensitive and challenging task as it would require opening nuclear depots for inspection. Politically, the two countries differ in the assessment of a future role of nuclear arms. While the US anticipates that further development of its advanced conventional capabilities would lead to diminishing the role of nuclear weapons, it is exactly the weakness of its conventional forces which causes the Russian defence establishment to project a growing role for nuclear weapons. These two distinct trajectories largely explain the differences in the two countries' approaches to the TNW arms control and make any agreement less likely to materialize any time soon. They also explain why Moscow has become increasingly sceptical with regard to including TNW within an arms control regime.
Low Conspicuity of Motorcycles for Car Drivers
Authors: Rogé Joceline , Douissembekov Evgueni , Vienne Fabrice
Published: December 2011

Objective: The aim of this study was to evaluate whether the low visibility of motorcycles is the result of their low cognitive conspicuity and/or their low sensory conspicuity for car drivers.

Background: In several cases of collision between a car and a motorcycle, the car driver failed to detect the motorcyclist in time to avoid the collision.

Method: To test the low cognitive conspicuity hypothesis, 42 car drivers (32.02 years old) including 21 motorcyclist motorists and 21 non–motorcyclist motorists carried out a motorcycle detection task in a car-driving simulator. To test the low sensory conspicuity hypothesis, the authors studied the effect of the color contrast between motorcycles and the road surface on the ability of car drivers to detect motorcycles when they appear from different parts of the road.

Results: A high level of color contrast enhanced the visibility of motorcycles when they appeared in front of the participants. Moreover, when motorcyclists appeared from behind the participants, the motorcyclist motorists detected oncoming motorcycles at a greater distance than did the non–motorcyclist motorists. Motorcyclist motorists carry out more saccades and rapidly capture information (on their rearview mirrors and on the road in front of them).

Conclusion: The results related to the sensory conspicuity and cognitive conspicuity of motorcycles for car drivers are discussed from the viewpoint of visual attention theories.

Application: The practical implications of these results and future lines of research related to training methods for car drivers are considered.
Managers’ Evaluations of Immigrant Job Applicants
Authors: Horverak Jøri Gytre , Bye Hege Høivik , Sandal Gro Mjeldheim , Pallesen Ståle
Published: December 2011

This study examined the impact of immigrant job applicants’ private domain acculturation preferences on managers’ evaluations of person-organization (P-O) fit and hiring decisions. We employed an experimental design and presented Norwegian managers ( N = 74) with video-clips of three job applicants. One of the applicants’ (target) ethnicity (Norwegian vs. Turkish) and private domain acculturation preferences (separated, assimilated, and integrated) were manipulated across four experimental conditions. Among the three applicants, the target applicant was presented as the best qualified. The results showed that the separated target was perceived as less similar to existing organizational members and the organization (i.e., lower supplementary P-O fit) than the three other targets, and as less valuable in terms of being different (i.e., lower complementary P-O fit) than the assimilated and the integrated targets. The separated target was rated significantly lower on hirability than the native and integrated targets. Despite the different hiring ratings, all targets received equal ratings on person-job (P-J) fit. The findings imply that managers placed a stronger emphasis on P-O fit than formal work competence when evaluating the separated target. Because private domain acculturation preferences can be deemed irrelevant for immigrant applicants’ job performance, our results suggest a biased employment decision against the immigrant applicant expressing private domain cultural maintenance preferences.
Evaluating the Efficacy of Remediation for Struggling Readers in High School
Authors: Lovett Maureen W. , Lacerenza Léa , De Palma Maria , Frijters Jan C.
Published: December 2011

Preliminary efficacy data are reported for a research-based reading intervention designed for struggling readers in high school. PHAST PACES teaches (a) word identification strategies, (b) knowledge of text structures, and (c) reading comprehension strategies. In a quasi-experimental design, 268 intervention and 83 waiting list control students meeting criteria for reading disability were assessed before and after their semester. After 60 to 70 hours of PHAST PACES instruction, struggling readers demonstrated significant gains on standardized tests of word attack, word reading, and passage comprehension and on experimental measures of letter–sound knowledge and multisyllabic word identification relative to control students. An average effect size of .68 was revealed across these outcome measures. One year follow-up data on 197 PHAST PACES students revealed an average trend to decelerated growth after the intervention, except for passage comprehension outcomes that demonstrated continued growth over follow-up.
The influence of mixed conventional sulfur/peroxide vulcanization systems on the mechanical and thermal properties of natural rubber/polypropylene blends
Authors: Thitithammawong Anoma , Uthaipan Nattapon , Rungvichaniwat Adisai
Published: December 2011

The role of mixed conventional sulfur/peroxide vulcanization systems on the mechanical and thermal properties of natural rubber/polypropylene thermoplastic vulcanizate (TPV) was investigated. Various proportions of peroxide in the mixed vulcanization system were used to dynamically vulcanize the natural rubber phase in the blend. The results show that using a mixed vulcanization system results in TPVs with superior properties in all areas studied, to those of TPVs cured by individual sulfur or peroxide systems. However, the peroxide content in the mixed vulcanization system has a strong effect on the variation in properties. A system containing 30 parts of peroxide to 70 parts of sulfur, results in a TPV with the best overall properties due to a balance of the effects of the sulfur and the peroxide curing agents in the blend. This ratio promotes optimum cross-link density, cross-link patterns, and low competing reactions of the peroxide and co-agents. As a result, improvements in the mechanical and thermal properties of the TPV are obtained with 30 parts of peroxide in the mixed system. Any further increase in the peroxide content results in a deterioration of those properties due to inefficient cross-linking with a high degree of competing reactions. Thus, close attention should be paid to the ratio of sulfur to peroxide or more specifically to the content of peroxide when selecting a mixed vulcanization system as a cross-link agent.
Positive Life Experiences
Authors: Peterson Jean Sunde , Canady Kate , Duncan Nancy
Published: December 2011

At the culmination of an 11-year qualitative, cross-sectional study of life events, 48 high-ability high school graduates fitting common stereotypes associated with giftedness completed an open-ended questionnaire, part of which focused on positive life experiences and sources of support. Findings included that intense investment in academics, activities, and service contributed to new perspectives, vision and direction, confidence in competence, social connections, spiritual growth, and additional opportunities. Some experiences were considered life-changing. Participants’ language reflected individual accomplishment, a dominant-culture value, but the main themes reflected fulfillment, validation, satisfaction, and, unexpectedly, many values associated with nonmainstream cultural groups. Findings are presented within a core-values framework associated with positive psychology.
Women’s Work and Working Conditions
Authors: Glauber Rebecca
Published: December 2011

Few studies have analyzed variation in the motherhood wage penalty by the sex composition of women’s jobs. This study draws on nationally representative data to investigate the motherhood wage penalty for women who work in female-dominated, male-dominated, and integrated jobs. Fixed-effects estimates reveal that women who work in female-dominated jobs pay a larger motherhood wage penalty than women who work in other jobs. This larger penalty is not offset by measurable compensating differentials, such as flexible scheduling or part-time work hours.
Assessment of multicomponent hydrogel scaffolds of poly(acrylic acid-2-hydroxy ethyl methacrylate)/gelatin for tissue engineering applications
Authors: Jaiswal Maneesh , Koul Veena
Published: December 2011

The article describes the design of the multicomponent hydrogel system of poly(acrylic acid-HEMA)/gelatin for tissue engineering application. Derivative of polycaprolactone-diol (polycaprolactone diacrylate (PCL-DAr)) was used to cross-link acrylate monomers whereas gelatin was kept free for cell proliferation. Epigallocatechin gallate (EGCG), an anti-oxidant phytochemical, was loaded by diffusion method. Its in vitro release study in PBS (pH 6.5) at 37 ± 0.2°C (75 rpm) revealed a sustained release profile upto 20 days. Fitting of drug release data in Korsmeyer-Peppas model equation revealed probable release mechanism through the value of release coefficient ( n), which was found to depend on formulations composition. Drug-polymer interaction, thermal behavior, and surface morphology were investigated by attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopic (SEM). Swelling behavior of hydrogel in PBS (pH 6.5 and 7.4, 0.2 M) and in distilled water was found to increase with increasing AAc/HEMA ratio. Compression modulus decreased from 203 ± 3.7 KPa to 11.6 ± 1.1KPa, at 30% strain, whereas displacement values significantly increased from 3.2 ± 0.2 to 4.7 ± 0.6 mm at 20 N force ( p < 0.05), with increasing AAc/HEMA ratio. Percentage cell viability was analyzed using indirect 3-[4, 5-dimethylthiazolyl-2]-2,5-diphenyltetrazo-liumbromide (MTT) assay with fibroblast L929 cells; showed ≥92.3% cell viability after 24 h incubation. Cell proliferation on the scaffold surface was found to increase with incorporation of HEMA in P(AAc)/G cross-linked hydrogel matrix upto a certain extent. These biocompatible, elastic, and swellable hydrogels can serve as a matrix for drug delivery and tissue engineering applications.
An evaluation of the processing conditions, structure, and properties (biaxial flexural strength and antibacterial efficacy) of sintered strontium–zinc–silicate glass ceramics
Authors: Looney Mark , Shea Helen O' , Gunn Lynda , Crowley Dolores , Boyd Daniel
Published: December 2011

The use of artificial bone grafts has increased in order to satisfy a growing demand for bone replacement materials. Initial mechanical stability of synthetic bone grafts is very advantageous for certain clinical applications. Coupled with the advantage of mechanical strength, a material with inherent antibacterial properties would be very beneficial. A series of strontium-doped zinc silicate (Ca–Sr–Na–Zn–Si) glass ceramics have been characterized in terms of their crystalline structure, biaxial flexural strength and antibacterial efficacy based on the identification of optimum sintering conditions. All three glass ceramics, namely, BT110, BT111, and BT112 were found to be fully crystalline, with BT111 and BT112 comprising of biocompatible crystalline phases. The biaxial flexural strengths of the three glass ceramics ranged from 70 to 149 MPa and were shown to be superior to those of clinically established ceramics in dry conditions and following incubation in simulated physiological conditions. The bacteriostatic effect for each glass ceramic was also established, where BT112 showed an inhibitory effect against three of the most common bacteria found at implantation sites, namely, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa. The results of the evaluation suggest that the materials studied offer advantages over current clinical materials and indicate the potential suitability of the glass ceramics as therapeutic bone grafts.
Neomycin and carbodiimide crosslinking as an alternative to glutaraldehyde for enhanced durability of bioprosthetic heart valves
Authors: Leong Joshua , Munnelly Amy , Liberio Brianna , Cochrane Leonard , Vyavahare Naren
Published: December 2011

Glutaraldehyde cross-linked porcine aortic valves, referred to as bioprosthetic heart valves (BHVs), are often used in heart valve replacements. Glutaraldehyde does not stabilize glycosaminoglycans (GAGs) and they are lost during preparation, in vivo implantation, cyclic fatigue, and storage. We report that binding of neomycin, a hyaluronidase inhibitor, to the tissues with carbodiimide cross-linking improves GAG retention without reducing collagen and elastin stability. It also led to improved biomechanical properties. Neomycin carbodiimide cross-linking did not significantly reduce calcification in a rat subdermal implantation model when they were stored in formaldehyde after cross-linking. Removal of formaldehyde storage significantly reduced calcification.
Ligation of the ovarian pedicles in dogs with a resorbable self-locking device – a long-term follow-up study
Authors: Höglund Odd V , Hagman Ragnvi , Olsson Kerstin , Carlsson Carolina , Södersten Fredrik , Lagerstedt Anne-Sofie
Published: December 2011

A prospective clinical trial was performed to evaluate applicability, hemostatic efficiency, and long-term tissue reactions of a novel medical device. The device was made of polydioxanone and designed in principle as a cable-tie with a flexible band running through a locking case. It was tested for ligation of the ovarian pedicles during ovariohysterectomy in nine intact female dogs. The dogs were followed-up monthly by physical examination and ultrasonography of the abdomen for 5–12 months after surgery. Macroscopic and histological post mortem examinations were performed in two dogs 7 and 18 months after surgery. Hemostasis was achieved with the devices although 1 of the 18 devices needed further tightening during a reoperation. Ultrasonography revealed a hyperechoic device that caused acoustic shadowing, which decreased over time indicating gradual resorption. Post mortem examinations demonstrated adhesions and a local transient tissue reaction at site of the device. The results show that the device may be a future alternative for ligation of ovarian pedicles in dogs.
Influence of screw holes and gamma sterilization on properties of phosphate glass fiber-reinforced composite bone plates
Authors: Han Na , Ahmed Ifty , Parsons Andrew J , Harper Lee , Scotchford Colin A , Scammell Brigitte E , Rudd Chris D
Published: December 2011

Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. For a material that degrades, the main advantage is that an implant would not necessitate a second surgical event for removal. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P2O5-40CaO-5Na2O-5Fe2O3 were used to reinforce PLA polymer. The purpose of this study was to assess the effect of screw holes in a range of PBG-reinforced PLA composites with varying fiber layup and volume fraction. The flexural properties obtained showed that the strength and modulus values increased with increasing fiber volume fraction; from 96 MPa to 320 MPa for strength and between 4 GPa and 24 GPa for modulus. Furthermore, utilizing a larger number of thinner unidirectional (UD) fiber prepreg layers provided a significant increase in mechanical properties, which was attributed to enhanced wet out and thus better fiber dispersion during production. The effect of gamma sterilization via flexural tests showed no statistically significant difference between the sterilized and nonsterilized samples, with the exception of the modulus values for samples with screw holes. Degradation profiles revealed that samples with screw holes degraded faster than those without screw holes due to an increased surface area for the plates with screw holes in PBS up to 30 days. Scanning electron microscope (SEM) analysis revealed fiber pullout before and after degradation. Compared with various fiber impregnation samples, with 25% volume fraction, 8 thinner unidirectional prepreg stacked samples had the shortest fiber pull-out lengths in comparison to the other samples investigated.
The role of fixed-term contracts at labour market entry in Poland: stepping stones, screening devices, traps or search subsidies?
Authors: Baranowska Anna , Gebel Michael , Kotowska Irena E
Published: December 2011

Poland has become an interesting outlier in Europe in terms of employment flexibility, with an extremely high incidence of fixed-term contracts, particularly at labour market entry. In this article, detailed retrospective data from the Polish School Leavers Survey are used to analyse the dynamics of entry and exit from fixed-term contracts. The results show that neither firm-based vocational training nor diplomas from more selective tertiary education institutions provide graduates better access to secure entry positions. Regarding exit dynamics, transition patterns from fixed-term contracts into unemployment suggest that the timing of exits often coincides with the date of becoming eligible to collect unemployment benefits. The results also imply that, in Poland, fixed-term contracts might serve employers by helping them to identify the best workers.
Dimensions of collectivism: occupation, community and the increasing role of memory and personal dynamics in the debate
Authors: McBride Jo , Lucio Miguel Martínez
Published: December 2011

This essay argues that the notion of there being a decline in collectivism does not adequately engage with a whole new set of initiatives within labour process theory on collectivism in its various forms. These debates demonstrate how diverse social influences and experiences, and the memory of previous experiences and collective endeavours, are essential features that must be acknowledged in terms of their implications. There are series of interventions on occupational identity, the everyday lives of workers, gender and ethnic relations and the experience of work that nourish our understanding of collectivism as a more complex and broader concept. Furthermore, how features and relations are mobilized, linked and developed is becoming a vital feature of how collectivism should be understood. It is argued that the nature of these relations needs to be a greater focus of the debate if we are to develop a more dynamic view of collectivism, and a more relevant one.
Europe and the economic crisis: forms of labour market adjustment and varieties of capitalism
Authors: Lallement Michel
Published: December 2011

The economic crisis that beset Europe in 2007 had a considerable impact on employment. Since 2008, unemployment has increased throughout Europe, but adjustment mechanisms affecting the labour market have varied from one country to another. By examining six representative European Union countries from the EU15, this article examines three types of adjustment involving segmentation, working hours and unemployment/underemployment. These adjustment systems, which originate from business strategy and which are partly supported by public policy measures, reflect the persistence of three varieties of capitalism in Europe.
The impact of citizenship on labour process: state, capital and labour control in South China
Authors: Peng Thomas
Published: December 2011

Sweatshops remain scattered around southern China where scholars have explored the despotic nature of labour control. However, an anomalous case of factory regime was found in Hengfa, a handbag manufacturing factory. This article studies workers’ voluntary and hard-working attitude toward work, the institutional arrangement that organizes such workers’ interests, as well as the broader context that generates workers’ consent toward these institutional arrangements. First, the residential-working compound of Hengfa and the dormitory curfew have shaped the labour process into a game pursuing leisure time outside of the factory. Second, China’s household registration system ( hukou) has determined inner-migrant workers’ residential status, making them rely on entrance guards and curfew as a protection for personal safety, and therefore has constructed the workers’ consent toward the curfew. Based on this analysis, a particular type of state-capital interrelation and its effect on the labour process can be found.
Assessing Attitudinal Barriers Toward End-of-Life Care
Authors: Parker Gary Dean , Smith Tim , Corzine Mitzi , Mitchell Glenn , Schrader Stuart , Hayslip Bert , Fanning Linda
Published: December 2011

Due to the rapid influx of Palliative care and Hospice services over the last decade, there has been an increase in the number of medical professionals interacting with terminal patients. One of the challenges with this growth becomes how to integrate these services into already busy practices along with providing physicians the education and tools they need to provide quality care. While there is no shortage of articles focusing on the educational needs of physicians related to end of life care, less is known about the level of anxiety physicians feel about interacting with dying patients and their families.
Strain as a Moderator of the Relationship Between Parental Attachment and Delinquent Participation
Authors: Liu Ruth X.
Published: December 2011

This study assesses the moderating influence of strain on the relationship between parental attachment and delinquent participation among Chinese adolescents. Drawing on survey reports of 1,866 middle-school students from Fuzhou City, China, multiple regression analyses yield results which show that the relationship between parental attachment and delinquency becomes weaker as adolescents report higher levels of status or achievement strain. Furthermore, despite reduced effect, parent–adolescent attachment continues to be inversely related to delinquency even at higher levels of achievement frustration. These results are discussed in light of China’s sociocultural setting and policy implications.
Judicial Accountability Versus the Separation of Powers
Authors: Minegar Steven R.
Published: December 2011

Judicial reformers worldwide have recently emphasized the need to increase judicial accountability through oversight committees known as judicial councils. In countries where the separation of powers doctrine is entrenched in the political culture, attempts to establish judicial councils have caused debate between strict interpretationists who favor an internal control model (comprised of judges) and loose interpretationists who favor an external control model (comprised of judges but also representatives from other government institutions). Disagreement over the composition of judicial councils defined the recent debate in Brazil over the establishment of the National Council of Justice (NCJ). This case study of the NCJ uses in-depth interviews with key figures in Brazil’s judicial system, along with congressional records and other secondary sources, to document the narratives of supporters and opponents of the NCJ. The results include competing views on the requisites of democratic governance, concerns about the politicization of the judiciary, as well as strictly definitional matters. By exploring the tension between judicial independence and accountability, and the way that additional considerations informed the debate over the NCJ in Brazil, this study reveals many factors that promote and that stand in the way of establishing effective judicial oversight.
A comparative study of family social capital and literacy practices in Singapore
Authors: Ren Li , Hu Guangwei
Published: December 2011

Social capital – the social relations between people – is an important component of the family environment and is crucial for the creation of human capital for the next generation. Drawing on James S. Coleman’s theory of family capital, this study focuses on parents’ utilization of social capital to support children’s literacy acquisition in four Singaporean and immigrant middle-class Chinese families in Singapore. Comparative analyses of observation and interview data reveal that these families differed not only in the volume of social capital they possessed but also in the activation of this capital for their children’s biliteracy and educational development. They also reveal that the parents’ application of social capital is motivated by such factors as the status of the family (immigrant or native), parental occupation, parents’ educational views and the family’s acculturation to the host society (in the case of immigrant families). Furthermore, a family’s skilful use of its social capital could compensate for a relative shortage of human capital. These findings, taken as a whole, contribute to Coleman’s theory by disentangling potential from actualized social capital.
Functional Decline Associated With Polypharmacy and Potentially Inappropriate Medications in Community-Dwelling Older Adults With Dementia
Authors: Lau Denys T. , Mercaldo Nathaniel D. , Shega Joseph W. , Rademaker Alfred , Weintraub Sandra
Published: December 2011

This study provides empirical evidence on whether polypharmacy and potentially inappropriate prescription medications (PIRx, as defined by the 2003 Beers criteria) increase the likelihood of functional decline among community-dwelling older adults with dementia. Data were from the National Alzheimer’s Coordinating Center, Uniform Data Set (9/2005-9/2009). Study sample included 1994 community-dwelling participants aged ≥65 with dementia at baseline. Results showed that participants having ≥5 medications were more likely to have functional decline than participants having <5 medications. However, the increased likelihood was only apparent in participants who did not have PIRx. Instead of magnifying the associated risk as hypothesized, PIRx appeared to have a protective effect albeit marginally statistically significant. Therefore, increased medication burden may be associated with functional decline in community-dwelling older adults with dementia who are not prescribed with PIRx. More research is needed to understand which classes of medications have the most deleterious effect on this population.
A new strategy for better genome assembly from very short reads
Authors: Ji Yan , Shi Yixiang , Ding Guohui , Li Yixue
Published: December 2011

Background

With the rapid development of the next generation sequencing (NGS) technology, large quantities of genome sequencing data have been generated. Because of repetitive regions of genomes and some other factors, assembly of very short reads is still a challenging issue.

Results

A novel strategy for improving genome assembly from very short reads is proposed. It can increase accuracies of assemblies by integrating de novo contigs, and produce comparative contigs by allowing multiple references without limiting to genomes of closely related strains. Comparative contigs are used to scaffold de novo contigs. Using simulated and real datasets, it is shown that our strategy can effectively improve qualities of assemblies of isolated microbial genomes and metagenomes.

Conclusions

With more and more reference genomes available, our strategy will be useful to improve qualities of genome assemblies from very short reads. Some scripts are provided to make our strategy applicable at http://code.google.com/p/cd-hybrid/.