bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of thong style flip‐flops on children's barefoot walking and jogging kinematics
Authors: Chard Angus , Greene Andrew , Hunt Adrienne , Vanwanseele Benedicte , Smith Richard
Published: March 2013

Background

Thong style flip‐flops are a popular form of footwear for children. Health professionals relate the wearing of thongs to foot pathology and deformity despite the lack of quantitative evidence to support or refute the benefits or disadvantages of children wearing thongs. The purpose of this study was to compare the effect of thong footwear on children's barefoot three dimensional foot kinematics during walking and jogging.

Methods

Thirteen healthy children (age 10.3 ± 1.6 SD years) were recruited from the metropolitan area of Sydney Australia following a national press release. Kinematic data were recorded at 200 Hz using a 14 camera motion analysis system (Cortex, Motion Analysis Corporation, Santa Rosa, USA) and simultaneous ground reaction force were measured using a force platform (Model 9281B, Kistler, Winterthur, Switzerland). A three‐segment foot model was used to describe three dimensional ankle, midfoot and one dimensional hallux kinematics during the stance sub‐phases of contact, midstance and propulsion.

Results

Thongs resulted in increased ankle dorsiflexion during contact (by 10.9°, p; = 0.005 walk and by 8.1°, p; = 0.005 jog); increased midfoot plantarflexion during midstance (by 5.0°, p; = 0.037 jog) and propulsion (by 6.7°, p; = 0.044 walk and by 5.4°, p;= 0.020 jog); increased midfoot inversion during contact (by 3.8°, p;= 0.042 jog) and reduced hallux dorsiflexion during walking 10% prior to heel strike (by 6.5°, p; = 0.005) at heel strike (by 4.9°, p; = 0.031) and 10% post toe‐off (by 10.7°, p; = 0.001).

Conclusions

Ankle dorsiflexion during the contact phase of walking and jogging, combined with reduced hallux dorsiflexion during walking, suggests a mechanism to retain the thong during weight acceptance. Greater midfoot plantarflexion throughout midstance while walking and throughout midstance and propulsion while jogging may indicate a gripping action to sustain the thong during stance. While these compensations exist, the overall findings suggest that foot motion whilst wearing thongs may be more replicable of barefoot motion than originally thought.
Improvement in self-reported confidence in nurses’ professional skills in the emergency department
Authors: Rautava Veli-Pekka , Palomäki Erika , Innamaa Tapio , Perttu Mika , Lehto Päivi , Palomäki Ari
Published: March 2013

Background

The aim of this study was to assess nurses’ self-reported confidence in their professional skills before and after an extensive Emergency Department (ED) reform in Kanta-Häme Central Hospital.

Methods

Emergency nurses participated in transitional training commencing two years before the establishment of the new organization in 2007. Training was followed by weekly practical educational sessions in the new ED. During this process nurses improved their transition skills, defined house rules for the new clinic and improved their knowledge of new technology and instruments. The main processes involving critically ill ED patients were described and modelled with an electronic flow chart software.

During the transitional training nurses compiled lists of practical skills and measures needed in the ED. These were updated after feedback from physicians in primary and secondary care and head physicians in Kanta-Häme Central Hospital. The final 189-item list comprised 15 different categories, each containing from 4 to 35 items. Based on the work described above, a questionnaire was developed to reflect ED nurses’ skills in clinical measures but also to estimate the need for professional education and practical training. Nurses working in the ED were asked to fill the questionnaire in January 2007 (response rate 97%) and in January 2011 (response rate 98%).

Results

Nurses’ self-reported confidence in their professional skills improved significally in eight classes out of fifteen. These classes were cannulations, urinary catheterizations, patient monitoring, cardiac patients, equipment, triage and nurse practising, psychiatric patients as well as infection risk. Best results were noted in urinary catheterizations, patient monitoring and infection risk. When studying the group of nurses participating in both surveys in 2007 and 2011, improvements were observed in all fifteen categories. All but two of these changes were significant (p<0.05).

Conclusions

During an extensive reform of emergency services, we noted a significant improvement in the professional skills of nurses. This improvement was especially consistent among nurses working in the ED during the whole transition process. Nurses’ education and training program in the ED may be successfully put into practice when based on co-operation between nurses and physicians dedicated to emergency services.
A gene-targeted approach to investigate the intestinal butyrate-producing bacterialcommunity
Authors: Vital Marius , Penton Christopher R , Wang Qiong , Young Vincent B , Antonopoulos Dion A , Sogin Mitchell L , Morrison Hilary G , Raffals Laura , Chang Eugene B , Huffnagle Gary B , Schmidt Thomas M , Cole James R , Tiedje James M
Published: March 2013

Background

Butyrate, which is produced by the human microbiome, is essential for awell-functioning colon. Bacteria that produce butyrate are phylogeneticallydiverse, which hinders their accurate detection based on conventional phylogeneticmarkers. As a result, reliable information on this important bacterial group isoften lacking in microbiome research.

Results

In this study we describe a gene-targeted approach for 454 pyrotag sequencing andquantitative polymerase chain reaction for the final genes in the two primarybacterial butyrate synthesis pathways, butyryl-CoA:acetate CoA-transferase(but) and butyrate kinase (buk). We monitored theestablishment and early succession of butyrate-producing communities in fourpatients with ulcerative colitis who underwent a colectomy with ileal pouch analanastomosis and compared it with three control samples from healthy colons. Allpatients established an abundant butyrate-producing community (approximately 5% to26% of the total community) in the pouch within the 2-month study, but patternswere distinctive among individuals. Only one patient harbored a community profilesimilar to the healthy controls, in which there was a predominance of butgenes that are similar to reference genes from Acidaminococcus sp.,Eubacterium sp., Faecalibacterium prausnitzii andRoseburia sp., and an almost complete absence of buk genes.Two patients were greatly enriched in buk genes similar to those ofClostridium butyricum and C. perfringens, whereas a fourthpatient displayed abundant communities containing both genes. Most butyrateproducers identified in previous studies were detected and the general patterns oftaxa found were supported by 16S rRNA gene pyrotag analysis, but thegene-targeted approach provided more detail about the potential butyrate-producingmembers of the community.

Conclusions

The presented approach provides quantitative and genotypic insights intobutyrate-producing communities and facilitates a more specific functionalcharacterization of the intestinal microbiome. Furthermore, our analysis refinesbut and buk reference annotations found in centraldatabases.
A Network Model of the Periodic Synchronization Process in the Dynamics of Calcium Concentration in GnRH Neurons
Authors: Krupa Maciej , Vidal Alexandre , Clément Frédérique
Published: March 2013

Mathematical neuroendocrinology is a branch of mathematical neurosciences that is specifically interested in endocrine neurons, which have the uncommon ability of secreting neurohormones into the blood. One of the most striking features of neuroendocrine networks is their ability to exhibit very slow rhythms of neurosecretion, on the order of one or several hours. A prototypical instance is that of the pulsatile secretion pattern of GnRH (gonadotropin releasing hormone), the master hormone controlling the reproductive function, whose origin remains a puzzle issue since its discovery in the seventies. In this paper, we investigate the question of GnRH neuron synchronization on a mesoscopic scale, and study how synchronized events in calcium dynamics can arise from the average electric activity of individual neurons. We use as reference seminal experiments performed on embryonic GnRH neurons from rhesus monkeys, where calcium imaging series were recorded simultaneously in tens of neurons, and which have clearly shown the occurrence of synchronized calcium peaks associated with GnRH pulses, superposed on asynchronous, yet oscillatory individual background dynamics. We design a network model by coupling 3D individual dynamics of FitzHugh–Nagumo type. Using phase-plane analysis, we constrain the model behavior so that it meets qualitative and quantitative specifications derived from the experiments, including the precise control of the frequency of the synchronization episodes. In particular, we show how the time scales of the model can be tuned to fit the individual and synchronized time scales of the experiments. Finally, we illustrate the ability of the model to reproduce additional experimental observations, such as partial recruitment of cells within the synchronization process or the occurrence of doublets of synchronization.
Involvement of TLR7 MyD88-dependent signaling pathway in the pathogenesis of adult-onset Still's disease
Authors: Chen Der-Yuan , Lin Chi-Chen , Chen Yi-Ming , Lan Joung-Liang , Hung Wei-Ting , Chen Hsin-Hua , Lai Kuo-Lung , Hsieh Chia-Wei
Published: March 2013

Introduction

The objective of this study was to investigate the potential role of the Toll-like receptor 7 (TLR7) signaling pathway in the pathogenesis of adult-onset Still's disease (AOSD).

Methods

Frequencies of TLR7-expressing precursor of myeloid dendritic cells (pre-mDCs) and mDCs in 28 AOSD patients, 28 patients with systemic lupus erythematosus (SLE) and 12 healthy controls (HC) were determined by flow cytometry analysis. Transcript and protein levels of TLR7 signaling molecules in peripheral blood mononuclear cells (PBMCs) were evaluated by quantitative PCR and western blotting respectively. Serum cytokines levels were measured by ELISA.

Results

Significantly higher median frequencies of TLR7-expressing pre-mDCs and mDCs were observed in AOSD patients (65.5% and 14.9%, respectively) and in SLE patients (60.3% and 14.4%, respectively) than in HC (42.8% and 8.8%, respectively; both P <0.001). Transcript and protein levels of TLR7-signaling molecules, including MyD88, TRAF6, IRAK4 and IFN-α, were upregulated in AOSD patients and SLE patients compared with those in HC. Disease activity scores were positively correlated with the frequencies of TLR7-expressing mDCs and expression levels of TLR7 signaling molecules in both AOSD and SLE patients. TLR7 ligand (imiquimod) stimulation of PBMCs resulted in significantly enhanced levels of interleukin (IL)-1β, IL-6, IL-18 and IFN-α in AOSD and SLE patients. Frequencies of TLR7-expressing mDCs and expression levels of TLR7 signaling molecules significantly decreased after effective therapy.

Conclusions

Elevated levels of TLR7 signaling molecules and their positive correlation with disease activity in AOSD patients suggest involvement of the TLR7 signaling pathway in the pathogenesis of this disease. The overexpression of TLR7 MyD88-dependent signaling molecules may be a common pathogenic mechanism for both AOSD and SLE.
Infusion of freshly isolated autologous bone marrow derived mononuclear cells prevents endotoxin-induced lung injury in an ex-vivo perfused swine model
Authors: Rojas Mauricio , Parker Richard E , Thorn Natalie , Corredor Claudia , Iyer Smita S , Bueno Marta , Mroz Lyle , Cardenes Nayra , Mora Ana L , Stecenko Arlene A , Brigham Kenneth L
Published: March 2013

Introduction

The acute respiratory distress syndrome (ARDS), affects up to 150,000 patients per year in the United States. We and other groups have demonstrated that bone marrow derived mesenchymal stromal stem cells prevent ARDS induced by systemic and local administration of endotoxin (lipopolysaccharide (LPS)) in mice.

Methods

A study was undertaken to determine the effects of the diverse populations of bone marrow derived cells on the pathophysiology of ARDS, using a unique ex-vivo swine preparation, in which only the ventilated lung and the liver are perfused with autologous blood. Six experimental groups were designated as: 1) endotoxin alone, 2) endotoxin + total fresh whole bone marrow nuclear cells (BMC), 3) endotoxin + non-hematopoietic bone marrow cells (CD45 neg), 4) endotoxin + hematopoietic bone marrow cells (CD45 positive), 5) endotoxin + buffy coat and 6) endotoxin + in vitro expanded swine CD45 negative adherent allogeneic bone marrow cells (cultured CD45neg). We measured at different levels the biological consequences of the infusion of the different subsets of cells. The measured parameters were: pulmonary vascular resistance (PVR), gas exchange (PO2), lung edema (lung wet/dry weight), gene expression and serum concentrations of the pro-inflammatory cytokines IL-1β, TNF-α and IL-6.

Results

Infusion of freshly purified autologous total BMCs, as well as non-hematopoietic CD45(-) bone marrow cells significantly reduced endotoxin-induced pulmonary hypertension and hypoxemia and reduced the lung edema. Also, in the groups that received BMCs and cultured CD45neg we observed a decrease in the levels of IL-1β and TNF-α in plasma. Infusion of hematopoietic CD45(+) bone marrow cells or peripheral blood buffy coat cells did not protect against LPS-induced lung injury.

Conclusions

We conclude that infusion of freshly isolated autologous whole bone marrow cells and the subset of non-hematopoietic cells can suppress the acute humoral and physiologic responses induced by endotoxemia by modulating the inflammatory response, mechanisms that do not involve engraftment or trans-differentiation of the cells. These observations may have important implications for the design of future cell therapies for ARDS.
Addressing the Challenge of Diversity in the Graduate Ranks: Good Practices Yield Good Outcomes
Authors: Thompson Nancy L. , Campbell Andrew G.
Published: March 2013

In this paper, we examine the impact of implementing three systemic practices on the diversity and institutional culture in biomedical and public health PhD training at Brown University. We hypothesized that these practices, designed as part of the National Institutes of Health–funded Initiative to Maximize Student Development (IMSD) program in the Division of Biology and Medicine, would have a positive effect on underrepresented minority (URM) recruitment and retention and objective measures of student success. These practices include: 1) develop strategic partnerships with selected undergraduate institutions; 2) provide a personalized education program of student support and skill-based modules to supplement discipline-based course work; and 3) transform institutional culture by engaging faculty in supporting diversity-related goals and practices. Data comparing URM numbers and key academic milestones before and after implementation of IMSD practices support the initial hypothesis and effectiveness of these practices at Brown. Program components are broadly applicable as best practices for others seeking to improve URM recruitment and achievements of graduate students traditionally underrepresented in the sciences.
CREATE Cornerstone: Introduction to Scientific Thinking, a New Course for STEM-Interested Freshmen, Demystifies Scientific Thinking through Analysis of Scientific Literature
Authors: Gottesman Alan J. , Hoskins Sally G.
Published: March 2013

The Consider, Read, Elucidate hypotheses, Analyze and interpret data, Think of the next Experiment (CREATE) strategy for teaching and learning uses intensive analysis of primary literature to improve students’ critical-thinking and content integration abilities, as well as their self-rated science attitudes, understanding, and confidence. CREATE also supports maturation of undergraduates’ epistemological beliefs about science. This approach, originally tested with upper-level students, has been adapted in Introduction to Scientific Thinking, a new course for freshmen. Results from this course's initial semesters indicate that freshmen in a one-semester introductory course that uses a narrowly focused set of readings to promote development of analytical skills made significant gains in critical-thinking and experimental design abilities. Students also reported significant gains in their ability to think scientifically and understand primary literature. Their perceptions and understanding of science improved, and multiple aspects of their epistemological beliefs about science gained sophistication. The course has no laboratory component, is relatively inexpensive to run, and could be adapted to any area of scientific study.
Prospective Randomized Phase II Trial of a Single Early Intravesical Instillation of Pirarubicin (THP) in the Prevention of Bladder Recurrence After Nephroureterectomy for Upper Urinary Tract Urothelial Carcinoma: The THP Monotherapy Study Group Trial
Authors: Ito Akihiro , Shintaku Ichiro , Satoh Makoto , Ioritani Naomasa , Aizawa Masataka , Tochigi Tatsuo , Kawamura Sadafumi , Aoki Hiroshi , Numata Isao , Takeda Atsushi , Namiki Shunichi , Namima Takashige , Ikeda Yoshihiro , Kambe Koichi , Kyan Atsushi , Ueno Seiji , Orikasa Kazuhiko , Katoh Shinnosuke , Adachi Hisanobu , Tokuyama Satoru , Ishidoya Shigeto , Yamaguchi Takuhiro , Arai Yoichi
Published: March 2013

Purpose

We evaluated the efficacy of a single early intravesical instillation of pirarubicin (THP) in the prevention of bladder recurrence after nephroureterectomy for upper urinary tract urothelial carcinoma (UUT-UC).

Patients and Methods

From December 2005 to November 2008, 77 patients clinically diagnosed with UUT-UC from 11 institutions participating in the Tohoku Urological Evidence-Based Medicine Study Group were preoperatively enrolled in this study. Patients were randomly assigned to receive or not receive a single instillation of THP (30 mg in 30 mL of saline) into the bladder within 48 hours after nephroureterectomy. Cystoscopy and urinary cytology were repeated every 3 months for 2 years or until the occurrence of first bladder recurrence.

Results

Seventy-two patients were evaluable for efficacy analysis, 21 of whom had a subsequent bladder recurrence. Significantly fewer patients who received THP had a recurrence compared with the control group (16.9% at 1 year and 16.9% at 2 years in the THP group v 31.8% at 1 year and 42.2% at 2 years in the control group; log-rank P = .025). No remarkable adverse events were observed in the THP-treated group. Based on multivariate analysis, THP instillation (hazard rate [HR], 0.26; 95% CI, 0.07 to 0.91; P = .035) and open surgery (HR, 0.28; 95% CI, 0.09 to 0.84; P = .024) were independently predictive of a reduced incidence of bladder recurrence.

Conclusion

In this prospective randomized phase II study, a single intravesical instillation of THP seemed to reduce bladder recurrence after nephroureterectomy. A phase III, large-scale, multicenter study is needed to confirm these observations.
Central Venous Catheter Care for the Patient With Cancer: American Society of Clinical Oncology Clinical Practice Guideline
Authors: Schiffer Charles A. , Mangu Pamela B. , Wade James C. , Camp-Sorrell Dawn , Cope Diane G. , El-Rayes Bassel F. , Gorman Mark , Ligibel Jennifer , Mansfield Paul , Levine Mark
Published: March 2013

Purpose

To develop an evidence-based guideline on central venous catheter (CVC) care for patients with cancer that addresses catheter type, insertion site, and placement as well as prophylaxis and management of both catheter-related infection and thrombosis.

Methods

A systematic search of MEDLINE and the Cochrane Library (1980 to July 2012) identified relevant articles published in English.

Results

The overall quality of the randomized controlled trial evidence was rated as good. There is consistency among meta-analyses and guidelines compiled by other groups as well.

Recommendations

There is insufficient evidence to recommend one CVC type or insertion site; femoral catheterization should be avoided. CVC should be placed by well-trained providers, and the use of a CVC clinical care bundle is recommended. The use of antimicrobial/antiseptic-impregnated and/or heparin-impregnated CVCs is recommended to decrease the risk of catheter-related infections for short-term CVCs, particularly in high-risk groups; more research is needed. The prophylactic use of systemic antibiotics is not recommended before insertion. Data are not sufficient to recommend for or against routine use of antibiotic flush/lock therapy; more research is needed. Before starting antibiotic therapy, cultures should be obtained. Some life-threatening infections require immediate catheter removal, but most can be treated with antimicrobial therapy while the CVC remains in place. Routine flushing with saline is recommended. Prophylactic use of warfarin or low–molecular weight heparin is not recommended, although a tissue plasminogen activator (t-PA) is recommended to restore patency to occluded catheters. CVC removal is recommended when the catheter is no longer needed or if there is a radiologically confirmed thrombosis that worsens despite anticoagulation therapy.
Validation of a Cell-Cycle Progression Gene Panel to Improve Risk Stratification in a Contemporary Prostatectomy Cohort
Authors: Cooperberg Matthew R. , Simko Jeffry P. , Cowan Janet E. , Reid Julia E. , Djalilvand Azita , Bhatnagar Satish , Gutin Alexander , Lanchbury Jerry S. , Swanson Gregory P. , Stone Steven , Carroll Peter R.
Published: March 2013

Purpose

We aimed to validate a previously described genetic risk score, denoted the cell-cycle progression (CCP) score, in predicting contemporary radical prostatectomy (RP) outcomes.

Methods

RNA was quantified from paraffin-embedded RP specimens. The CCP score was calculated as average expression of 31 CCP genes, normalized to 15 housekeeper genes. Recurrence was defined as two prostate-specific antigen levels ≥ 0.2 ng/mL or any salvage treatment. Associations between CCP score and recurrence were examined, with adjustment for clinical and pathologic variables using Cox proportional hazards regression and partial likelihood ratio tests. The CCP score was assessed for independent prognostic utility beyond a standard postoperative risk assessment (Cancer of the Prostate Risk Assessment post-Surgical [CAPRA-S] score), and a score combining CAPRA-S and CCP was validated.

Results

Eighty-two (19.9%) of 413 men experienced recurrence. The hazard ratio (HR) for each unit increase in CCP score (range, −1.62 to 2.16) was 2.1 (95% CI, 1.6 to 2.9); with adjustment for CAPRA-S, the HR was 1.7 (95% CI, 1.3 to 2.4). The score was able to substratify patients with low clinical risk as defined by CAPRA-S ≤ 2 (HR, 2.3; 95% CI, 1.4 to 3.7). Combining the CCP and CAPRA-S improved the concordance index for both the overall cohort and low-risk subset; the combined CAPRA-S + CCP score consistently predicted outcomes across the range of clinical risk. This combined score outperformed both individual scores on decision curve analysis.

Conclusion

The CCP score was validated to have significant prognostic accuracy after controlling for all available clinical and pathologic data. The score may improve accuracy of risk stratification for men with clinically localized prostate cancer, including those with low-risk disease.
Synthesis of Polymer–Metal Hybrid Nanoparticle by Photopolymerization of Vinyl Cinnamate in Gas Phase
Authors: Kudoh Satoshi , Orii Takaaki
Published: March 2013

Polymeric vinyl cinnamate (VC)–silver hybrid nanoparticles were synthesized by near-UV irradiation of VC vapor containing silver nanoparticles. The size increase of treated silver nanoparticles was observed using a differential mobility analyzer. The mass spectra of the nanoparticles suggested the presence of photopolymerization products.
New Synthetic Host Pillararenes: Their Synthesis and Application to Supramolecular Materials
Authors: Ogoshi Tomoki , Yamagishi Tada-aki
Published: March 2013

In 2008, we reported a new class of macrocyclic hosts called “pillararenes.” They combine the advantages and aspects of traditional hosts and have a composition similar to those of typical calixarenes. Pillararenes have repeating units connected by methylene bridges at the para-position of benzene moieties, and thus they have a unique symmetric pillar architecture differing from the basket-shaped structure of calixarenes bridged at the meta-position of benzene moieties. Pillararenes show high functionality similar to cyclodextrins and can capture electron-accepting guest molecules within their cavity similarly to cucurbiturils. In this account, the synthesis, structure, and host–guest properties are discussed, along with pillararene-based supramolecular architectures.
Stability of Graphene Oxide Film to Electron Beam Irradiation and Possible Thickness Dependence of Electron Attenuation
Authors: Sugimoto Tatsuya , Kimura Keisaku
Published: March 2013

Graphene oxide (GO), one of the best transparent substrates for electron microscopy of biological substances, is known to be not very stable to exposure to electron beams (e-beams). We present a method of the preparation of GO film highly resistive to e-beams by controlling layer-by-layer thickness and quantitatively examined the stability of GO film thus prepared. Scanning transmission electron microscopic measurements were engaged in these films with 10-kV acceleration-voltage. A simple method is proposed to classify the layer structure of GO. As an application of the method, we determined the electron attenuation length through GO film in nm scale.
Highly Selective Tetrakis(bipyridinium–crown ether)-conjugated Chemosensor for Barium Ions
Authors: Guo Haocheng , Kuwabara Tetsuo
Published: March 2013

A novel guest-responsive color-change host, 1, possessing four bipyridinium-modified benzocrown ethers, was prepared, and its ion-recognition ability was investigated. 1 exhibited a yellow color associated with intramolecular charge-transfer (CT) absorption, which faded upon the addition of alkali metal and alkaline earth metal ions. 1 detected Ba2+ with high sensitivity.
Alleviating the Patient's Price of Privacy Through a Partially Observable Waiting List
Authors: Sandıkçı Burhaneddin , Maillart Lisa M. , Schaefer Andrew J. , Roberts Mark S.
Published: March 2013

In the United States, end-stage liver disease patients join a waiting list and then make accept/reject decisions for transplantation as deceased-donor organs are offered to them over time. These decisions are largely influenced by the patient's prospect for future offers, which can be ascertained most accurately by knowing the entire composition of the waiting list. Under the current transplantation system, however, the United Network for Organ Sharing (UNOS), in an effort to strike a balance between privacy and transparency, only publishes an aggregated version of the waiting list. However, it is not clear whether the published information is good enough (compared with perfect information) to help patients make optimal decisions that maximize their individual life expectancies. We provide a novel model of this accept/reject problem from an individual patient's perspective using a partially observed Markov decision process (POMDP) framework, which incorporates the imperfect waiting list information as published currently into the patient's decision making. We analyze structural properties of this model. In particular, we establish conditions that guarantee a monotone value function and a threshold-type optimal policy with respect to the partially observable rank state that captures the imperfect waiting list information. Furthermore, we develop an improved solution methodology to solve a generic POMDP model. This solution method guarantees, for any fixed grid, the best possible approximation to the optimal value function by solving linear programs to compute the optimal weights used for the approximation. Finally, we compare, in a clinically driven numerical study, the results of this model with those of an existing Markov decision process model that differs from our model in assuming the availability of perfect waiting list information. This comparison allows us to assess the quality of the published imperfect information as measured by a patient's so-called price of privacy (i.e., the opportunity loss in expected life days due to a lack of perfect waiting list information). Previous work estimates a significant loss in a patient's life expectancy, on average, when the patient has no waiting list information compared with full information. In this paper, we find that the currently published partial information is nearly sufficient to eliminate this loss, resulting in a negligible price of privacy and supporting current UNOS practice.

This paper was accepted by Assaf Zeevi, stochastic models and simulation.
Contract Design with a Dominant Retailer and a Competitive Fringe
Authors: Kolay Sreya , Shaffer Greg
Published: March 2013

We show that under some conditions, quantity discounts and two-part tariffs are equivalent as mechanisms for channel coordination when an upstream firm sells its product in a downstream market that is characterized by a dominant retailer and a competitive fringe. We consider a setting in which discriminatory offers are feasible and a setting in which the same menu of options must be offered to all retailers. We find that the upstream firm's profit in both settings is independent of whether quantity discounts or two-part tariffs are used. The implication of this finding is that the firm's choice of contract design may turn on which one is easier to implement.

This paper was accepted by J. Miguel Villas-Boas, marketing.
Open reduction for developmental dysplasia of the hip: failures of screening or failures of treatment?
Authors: Sanghrajka AP , Murnaghan CF , Shekkeris A , Eastwood DM
Published: March 2013

Introduction

The aim of this study was to define the clinical indications and demographic characteristics of patients undergoing open reduction for developmental dysplasia of the hip (DDH), and determine the proportion due to preventable failures of contemporary clinical screening and early management.

Methods

Case notes were reviewed of consecutive primary open reductions performed for non-teratologic hip dislocation at the Great Ormond Street Hospital for Children over a five-year period. Forty-eight patients (64 hips) were suitable for inclusion. A telephone survey confirmed selective hip ultrasonography screening protocols were employed in all maternity hospitals in our referral base.

Results

There were no cases of open reduction for unilateral DDH following Pavlik treatment commenced by six weeks of age, highlighting the importance of early detection and treatment. Eleven cases (23%) may have been avoided by appropriate implementation of existing selective ultrasonography screening protocols. Thirty-four cases (71%) presented after four months of age, suggesting open reduction is associated with late diagnosis rather than failure of primary management. None of these patients had neonatal hip ultrasonography and only 12% (4 patients) had a risk factor that should have triggered a scan.

Conclusions

Compared with published results, the contemporary screening practices in our referral base are failing to eliminate late presenting DDH and the need for open surgical reduction. Changes in strategy and implementation are required to significantly improve screening efficacy.
Austerity justice
Authors: Hynes Steve
Published: March 2013

With the continuing economic downturn and major legislative changes, such as the introduction of Universal Credit, demand for advice services is likely to continue to increase, but civil legal aid services will be subject to devastating cuts from April 2013. In this article, drawing on recent research, Steve Hynes, the Director of Legal Action Group (LAG), discusses why civil legal aid has reached this low point and the impact of the loss this source of support for advice on welfare benefits and other common civil legal problems.
Students’ Understanding of Cells & Heredity: Patterns of Understanding in the Context of a Curriculum Implementation in Fifth & Seventh Grades
Authors: Cisterna Dante , Williams Michelle , Merritt Joi
Published: March 2013

This study explores upper-elementary and early-middle-school students’ ideas about cells and inheritance and describes patterns of understanding for these topics. Data came from students’ responses to embedded assessments included in a technology-enhanced curriculum designed to help students learn about cells and heredity. Our findings suggest that the instruction aided students in progressing to more sophisticated levels of understanding, especially by reviewing non-normative ideas and integrating new content into their previous understandings. Students, however, tended to struggle in distinguishing genes, chromosomes, and DNA and had some difficulties connecting the cell division process with the inheritance of genetic material.
Race to Displace: A Game to Model the Effects of Invasive Species on Plant Communities
Authors: Hopwood Jennifer L. , Flowers Susan K. , Seidler Katie J. , Hopwood Erica L.
Published: March 2013

Invasive species are a substantial threat to biodiversity. Educating students about invasive species introduces fundamental concepts in biology, ecology, and environmental science. In the Race to Displace game, students assume the characteristics of select native or introduced plants and experience first hand the influences of species interactions and changing environmental conditions on community composition as they advance across a game board. Through game play, students learn about ways in which species can interact, as well as attributes of successful invaders and the impacts of invasion on communities.
Regulation of Cation Balance inSaccharomyces cerevisiae
Authors: Cyert Martha S , Philpott Caroline C
Published: March 2013

All living organisms require nutrient minerals for growth and have developed mechanisms to acquire, utilize, and store nutrient minerals effectively. In the aqueous cellular environment, these elements exist as charged ions that, together with protons and hydroxide ions, facilitate biochemical reactions and establish the electrochemical gradients across membranes that drive cellular processes such as transport and ATP synthesis. Metal ions serve as essential enzyme cofactors and perform both structural and signaling roles within cells. However, because these ions can also be toxic, cells have developed sophisticated homeostatic mechanisms to regulate their levels and avoid toxicity. Studies in Saccharomyces cerevisiae have characterized many of the gene products and processes responsible for acquiring, utilizing, storing, and regulating levels of these ions. Findings in this model organism have often allowed the corresponding machinery in humans to be identified and have provided insights into diseases that result from defects in ion homeostasis. This review summarizes our current understanding of how cation balance is achieved and modulated in baker’s yeast. Control of intracellular pH is discussed, as well as uptake, storage, and efflux mechanisms for the alkali metal cations, Na+ and K+, the divalent cations, Ca2+ and Mg2+, and the trace metal ions, Fe2+, Zn2+, Cu2+, and Mn2+. Signal transduction pathways that are regulated by pH and Ca2+ are reviewed, as well as the mechanisms that allow cells to maintain appropriate intracellular cation concentrations when challenged by extreme conditions, i.e., either limited availability or toxic levels in the environment.
Triglyceride to HDL-C Ratio and Increased Arterial Stiffness in Children, Adolescents, and Young Adults
Authors: Urbina Elaine M. , Khoury Philip R. , McCoy Connie E. , Dolan Lawrence M. , Daniels Stephen R. , Kimball Thomas R.
Published: March 2013

BACKGROUND AND OBJECTIVE:

Lipid levels are linked to early atherosclerosis. Risk stratification may be improved by using triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), which relates to arterial stiffness in adults. We tested whether TG/HDL-C was an independent predictor of arterial stiffness in youth.

METHODS:

Subjects 10 to 26 years old (mean 18.9 years, 39% male, 56% non-Caucasian, n = 893) had laboratory, anthropometric, blood pressure, and arterial stiffness data collected (brachial distensibility, augmentation index, carotid-femoral pulse-wave velocity). Subjects were stratified into tertiles of TG/HDL-C (low, n = 227; mid, n = 288; high, n = 379).

RESULTS:

There was a progressive rise in cardiovascular (CV) risk factors and arterial stiffness across TG/HDL-C ratio. The high TG/HDL-C ratio group had the stiffest vessels (all P < .03 by analysis of variance). TG/HDL-C as a continuous variable was an independent determinant of brachial distensibility in CV risk factor adjusted model and for carotid-femoral pulse-wave velocity in obese subjects, with trend for higher augmentation index.

CONCLUSIONS:

TG/HDL-C, an estimate of small, dense low-density lipoprotein cholesterol, is an independent determinant of arterial stiffness in adolescents and young adults, especially in obese youth. These data suggest that use of TG/HDL-C may be helpful in identifying young adults requiring aggressive intervention to prevent atherosclerotic CV diseases.
Temperature dependent behavior of flat and bulk heterojunction organic solar cells
Authors: Widmer Johannes , Leo Karl , Riede Moritz
Published: March 2013

The open-circuit voltage of an organic solar cell is increasing with decreasing temperature and with increasing illumination intensity. These dependencies are quantitatively investigated for two types of organic solar cells, one with a flat donor-acceptor heterojunction and one with a mixed layer bulk heterojunction. Zinc-phthalocyanine and C60 are used as donor and acceptor, respectively. A qualitative difference is found for the two geometries. We find that a logarithmic illumination intensity dependence with temperature as a linear pre-factor of the logarithm, which is commonly reported and observed, is applicable for the bulk heterojunction. The flat heterojunction, in contrast, shows a constant illumination intensity pre-factor which is independent of the temperature, and the temperature can be modeled as additional linear summand.
Hall Effect Measurement System for Characterization of Doped Single Crystal Diamond
Authors: Berkun Isil , Demlow Shannon N. , Suwanmonkha Nutthamon , Hogan Timothy P. , Grotjohn Timothy A.
Published: March 2013

A temperature dependent Hall Effect measurement system with software based data acquisition and control was built and tested. Transport measurements are shown for boron-doped single crystal diamond (SCD) films deposited in a microwave plasma-assisted chemical vapor deposition (MPCVD) reactor. The influence of Ohmic contacts and temperature control accuracy are studied. For a temperature range of 300K-700K IV curves, Hall mobilities and carrier concentrations are presented.
Plastic Deformation of Directionally-Solidified MoSi2/Mo5Si3 Eutectic Composites
Authors: Sasai Yuta , Inoue Atsushi , Fujiwara Kosuke , Kishida Kyosuke , Inui Haruyuki
Published: March 2013

Deformation behavior of the directionally-solidified MoSi2/Mo5Si3 eutectic composites has been investigated as a function of the average thickness of MoSi2 phase over a temperature range from 900 to 1500°C. The average thickness of both MoSi2 and Mo5Si3 phases in the directionally-solidified ingots with script-lamellar morphologies grown by optical floating zone method decreases with increasing the growth rate. Plastic deformation was observed above 1000°C for all the DS ingots grown at different growth rates when the loading axis is parallel to [1¯10]MoSi2 close to the growth direction. Yield stress decreases monotonically with increasing temperature. Yield stress at 1400°C increases drastically with decreasing the average thickness of MoSi2 phase.
Infrared and Raman Spectroscopic Study of Glasses in the Al2O3-B2O3-Fe2O3-Na2O-SiO2 System
Authors: Stefanovsky S.V. , Fox K.M. , Marra J.C.
Published: March 2013

Glasses in the Al2O3-B2O3-Fe2O3-Na2O-SiO2 system were produced at a temperature of 1150 °C, poured onto a metal plate and annealed. The nature of the structural units and their bonding in the structure were studied by infrared and Raman spectroscopic techniques. The structural network of all the glasses studied is built from major [SiO4] tetrahedra with 2-3 non-bridging oxygens (NBO). Incorporation of Fe2O3 offers a destructive effect in the glass network.
The Effects of Structure on the Formation of Schottky Barriers at Nanoparticle-Oxide Interfaces
Authors: Kraya Ramsey , Kraya Laura Y.
Published: March 2013

The surface structure of oxide materials may be the limiting factor in controlling switching properties at interfaces. Here we investigate and correlate the surface structure and electronic properties of BaTiO3 substrates. By using low energy electron diffraction and scanning tunneling microscopy we are able to identify surface reconstructions based on annealing treatments. We then investigate the effect of contact size on the transport properties on oxide surfaces utilizing atomic force microscopy. Our results show the critical importance of controlling surface structure to optimize electronic properties at oxide interfaces.
Evolution of nucleation sites and bubble precursors in silicon as a function of helium implanted dose
Authors: Liu Changlong , Delamare R. , Ntsoenzok E. , Regula G. , Pichaud B. , Veen A.Van
Published: March 2013

(111) oriented silicon samples were implanted at room temperature with 1.55 MeV 3He ions in the dose range of 5×1015 to 5×1016/cm2. Cross-sectional transmission electron microscopy (XTEM) was used to study the evolution of bubbles and extended defects during subsequent thermal annealing at 800°C and 900°C for 30min. The He desorption from bubbles and bubble precursors was measured by means of nuclear reaction analysis (NRA). TEM observations show that no bubbles were observed in Si implanted at doses lower than 1×1016/cm2, while a well-defined cavity band was formed after implantation at 5×1016/cm2 and subsequent thermal annealing. At the intermediary dose of 2×1016/cm2, however, the evolution of bubbles and extended defects is quite different. The bubbles prefer to nucleate in large planar clusters surrounded by a high density of dislocation loops emerging from them. The clusters of bubbles act as the sources of the dislocation loops. NRA measurements indicate that the He desorption behavior is also dose-dependent. The He desorption is achieved much faster in low dose implanted Si. The results are qualitatively discussed.
Drill Pipe Riser Intervention System Successful Experience in Offshore West Africa
Authors: Rohart Christophe , de Fonvielle Henri , Bordet Laurent , Campbell William , Susak Nenad , Marajh Mitra
Published: March 2013

While offshore intervention on subsea equipments is quite common, the increasingly deeper water operations require light weight intervention systems while meeting safe and stringent operating specification. For these new deep offshore challenges, the conventional risers are becoming a more costly and less desirable solution.

Starting with a recollection of the main drivers that motivated the development of drill pipe riser intervention systems (DPRISi), the paper details the technical and economical challenges in West Africa that have led to the design of such a solution. When non productive time and financial aspects are taken into account, it makes sense to develop a dedicated system in order to provide fast and reliable intervention.

Depending on the field requirements, two different types of drill pipe riser systems using a proprietary double shoulder connection were used by operators. A first solution was developed in 1999 featuring a seal ring close to the external shoulder. Subsequently, a new solution featuring a gas-tight metal to metal seal on the pin nose was developed in order to address increasingly demanding and challenging operations.

Intensively used in West Africa since 1999, the solution using the seal ring has shown robustness and reliability while being used for several projects in Angola such as Girassol and Rosa and now GirRI. The paper draws a summary of these operations and the feedback on the field use and maintenance. Also it emphasises the successful qualification process for the metal to metal seal solution that has been used in offshore Nigeria since 2010 for the USAN project.
Comparing Soft-String and Stiff-String Methods Used to Compute Casing Centralization
Authors: Gorokhova Lidia , Parry Andrew , Flamant Nicolas
Published: March 2013

Good casing centralization during cementing operations is a key factor for achieving proper mud displacement and obtaining hydraulic isolation in the annulus. To this end, centralizers are often placed along the casing to position it centrally in the borehole. The optimal number of centralizers and their spacing is determined with simulation software.

Until now, the industry has typically used calculation methods derived from API Spec. 10D to predict casing eccentricity in the wellbore. The calculations are based on an analytical soft-string method, which models an element of casing string between two centralizers as a bi-fixed beam.

However, in drilling operations, the use of a numerical stiff-string method to compute torque-and-drag forces is now becoming widespread. It accounts for tubular bending stiffness and provides a more realistic analysis of the stresses and loads acting upon the drillstring and the borehole. The stiff-string technique based on the finite-element method is thus proposed as an alternate and more effective solution for computing casing centralization for cementing operations.

Measured and calculated casing centralizations were compared in several field cases. The casing eccentricity was measured after the cement placement using recently developed ultrasonic logging tools and diagnostics. Discrepancies between analytical and numerical calculation methods were analyzed, then advantages and disadvantages to each method were assessed. The results of the calculation methods were used to formulate an optimal approach to casing centralization.