bluuebunny/crossref_metadata_2025_split huggingface dataset:
The application of the challenge point framework in medical education
Authors: Guadagnoli Mark , Morin Marie‐Paule , Dubrowski Adam 
Published: April 2012

Medical Education 2012: 46: 447–453Objectives  The current paper describes a model of learning that has been used to produce efficient learning, thus yielding greater retention of information and superior performance under stress. In this paper, the model is applied to the learning of technical skills.Structure  After a brief review of the learning–performance paradox and other relevant literature from the field of movement science, the benefits of challenge and adversity for learning are discussed in the context of a framework for learning known as the challenge point framework (CPF). The framework is based on laboratory and field studies of methods that have been shown to consistently enhance learning, and is used to model and generate insight into the relationships between practice protocols and the learning that results from them.Application  The practical application of the CPF to simulation‐based medical education and training is described. Firstly, a simple conceptual model that utilises three key elements to adjust the functional difficulty of the tasks to be learned is outlined. Secondly, a number of assessment strategies that may be necessary to ensure that the trainee remains in the optimal learning zone are proposed. Thirdly, a practical example is used to demonstrate how to utilise this conceptual model to design simulation environments suitable for teaching an endotracheal intubation task to beginners and more advanced trainees.
Reflection as a strategy to foster medical students’ acquisition of diagnostic competence
Authors: Mamede Sílvia , van Gog Tamara , Moura Alexandre S , de Faria Rosa M D , Peixoto José M , Rikers Remy M J P , Schmidt Henk G 
Published: April 2012

Medical Education 2012: 46: 464–472Objectives  Developing diagnostic competence in students is a major goal of medical education, but there is little empirical evidence on instructional strategies that foster the acquisition of this competence. The aim of this study was to investigate the effects of structured reflection compared with the generation of immediate or differential diagnosis while practising with clinical cases on learning clinical diagnosis.Methods  This was a three‐phase experimental study. During a learning phase, 46 Year 4 students diagnosed six clinical cases under different experimental conditions: structured reflection, immediate diagnosis, or differential diagnosis. This was followed by an immediate test and a delayed test administered 1 week later. Each test consisted of diagnosing four different cases of diseases presented in the learning phase. Performance in diagnosing these new cases was used as a measure of learning.Results  Repeated‐measures analysis of variance on the mean diagnostic accuracy scores (range: 0–1) showed a significant interaction between performance moment (i.e. performance in the learning phase and on each test) and instructions followed during the learning phase (p = 0.003). Follow‐up analyses of this interaction showed that diagnostic performance did not differ between conditions in the learning phase. On the immediate test, scores in the reflection condition (mean = 0.48, 95% confidence interval [CI] 0.38–0.58) were significantly lower than scores in the differential diagnosis condition (mean = 0.62, 95% CI 0.54–0.70; p = 0.012) and marginally lower than those in the immediate diagnosis condition (mean = 0.61, 95% CI 0.52–0.70; p = 0.04). One week later, however, scores in the reflection condition (mean = 0.66, 95% CI 0.56–0.76) significantly outperformed those in the other conditions (differential diagnosis: mean = 0.48, 95% CI 0.37–0.58 [p < 0.01]; immediate diagnosis: mean = 0.52, 95% CI 0.43–0.60 [p = 0.01]). Comparisons within experimental conditions showed that performance from the immediate to the delayed test decreased in the immediate and differential diagnosis conditions (immediate diagnosis: p = 0.042; differential diagnosis: p = 0.012), but increased in the reflection condition (p = 0.003).Conclusions  Structured reflection while practising with cases appears to foster the learning of clinical knowledge more effectively than the generation of immediate or differential diagnoses and therefore seems to be an effective instructional approach to developing diagnostic competence in students.
Phosphorylation of histone H2A is associated with centromere function and maintenance in meiosis
Authors: Dong Qianhua , Han Fangpu 
Published: April 2012

SummaryHistone phosphorylation is dynamically regulated during cell division, for example phosphorylation of histone H3 (H3)‐Ser10, H3‐Thr11 and H3‐Ser28. Here we analyzed maize (Zea mays L) for Thr133‐phosphorylated histone H2A, which is important for spindle checkpoint control and localization of the centromere cohesion protector Shugoshin in mammals and yeast. Immunostaining results indicate that phosphorylated H2A‐Thr133 signals bridged those of the centromeric H3 histone variant CENH3 by using a plant displaying yellow fluorescent protein‐CENH3 signals and H2A‐Thr133 is phosphorylated in different cell types. During mitosis, H2A‐Thr133 phosphorylation becomes strong in metaphase and is specific to centromere regions but drops during later anaphase and telophase. Immunostaining for several maize dicentric chromosomes revealed that the inactive centromeres have lost phosphorylation of H2A‐Thr133. During meiosis in maize meiocytes, H2A phosphorylation becomes strong in the early pachytene stage and increases to a maximum at metaphase I. In the maize meiotic mutant afd1 (absence of first division), sister chromatids show equational separation at metaphase I, but there are no changes in H2A‐Thr‐133 phosphorylation during meiosis compared with the wild type. In sgo1 mutants, sister chromatids segregate randomly during meiosis II, and phosphorylation of H2A‐Thr‐133 is observed on the centromere regions during meiosis II. The availability of such mutants in maize that lack sister cohesion and Shugoshin indicate that the signals for phosphorylation are not dependent on cohesion but on centromere activity.
Functional identification of the phosphorylation sites of Arabidopsis PIN‐FORMED3 for its subcellular localization and biological role
Authors: Ganguly Anindya , Lee Sang‐Ho , Cho Hyung‐Taeg 
Published: April 2012

SummaryDirectional cell‐to‐cell movement of auxin is mediated by asymmetrically localized PIN‐FORMED (PIN) auxin efflux transporters. The polar localization of PINs has been reported to be modulated by phosphorylation. In this study, the function of the phosphorylation sites of the PIN3 central hydrophilic loop (HL) was characterized. The phosphorylation sites were located in two conserved neighboring motifs, RKSNASRRSF(/L) and TPRPSNL, where the former played a more decisive role than the latter. Mutations of these phosphorylatable residues disrupted in planta phosphorylation of PIN3 and its subcellular trafficking, and caused defects in PIN3‐mediated biological processes such as auxin efflux activity, auxin maxima formation, root growth, and root gravitropism. Because the defective intracellular trafficking behaviors of phospho‐mutated PIN3 varied according to cell type, phosphorylation codes in PIN3‐HL are likely to operate in a cell‐type‐specific manner.
Factors related to health locus of control among lung transplant candidates
Authors: Burker Eileen J. , Phillips Kristin M. , Giza Mallory 
Published: April 2012

AbstractAs the number of individuals pursuing lung transplantation to treat lung disease increases, transplant team members have an opportunity to maximize patients' chances for post‐transplant success through identifying and addressing psychosocial factors that have been previously associated with patients' post‐transplant survival, such as health locus of control (HLC). The purpose of this cross‐sectional study was to understand the factors associated with HLC in lung transplant candidates. The aims were to (i) identify the demographic factors associated with internal (IHLC), chance (CHLC), and powerful others (PHLC) HLC; (ii) examine the associations between HLC and anxiety, depression, and optimism; and (iii) determine whether these factors explain a significant proportion of variance in HLC. Hierarchical regression analyses indicated that age, education, trait anxiety, and optimism explained 20% of the variance in CHLC; gender, trait anxiety, and depression accounted for 9% of the variance in IHLC; and lower education accounted for 5% of the variance in PHLC. Helping transplant team members understand the factors that influence patients' perceptions that their own behaviors impact their health status is important for maximizing post‐transplant success.
Prevention of relapse using DLI can increase survival following HLA‐identical transplantation in patients with advanced‐stage acute leukemia: a multi‐center study
Authors: Wang Yu , Liu Dai‐Hong , Fan Zhi‐Ping , Sun Jing , Wu Xiao‐Jin , Ma Xiao , Xu Lan‐Ping , Liu Kai‐Yan , Liu Qi‐Fa , Wu De‐Pei , Huang Xiao‐Jun 
Published: April 2012

AbstractA total of 123 consecutive patients with advanced‐stage, acute leukemia undergoing HSCT from HLA‐identical sibling donors were analyzed. A G‐CSF‐primed DLI was planned within day 60 post‐transplantation before hematologic relapse was diagnosed. Fifty of the 123 individuals received prophylactic DLI, and 73 individuals received no prophylactic treatment. The incidence of grades II–IV acute graft‐versus‐host disease (GVHD) was 17% for patients receiving DLI and 23% for patients not receiving DLI (p = 0.35). The incidence of chronic GVHD was 38% for patients receiving DLI and 17% for patients not receiving DLI (p = 0.021). The two‐yr cumulative incidence of relapse was significantly lower in patients who received prophylactic DLI (46%) compared with patients who did not receive prophylactic DLI (66%) (p = 0.02). The three‐yr probability of overall survival was higher in patients who received prophylactic DLI (36%) than in patients who did not receive prophylactic DLI (11%) (p = 0.001). The leukemia‐free survival was also higher in patients who received prophylactic DLI (29%) than in patients who did not receive prophylactic DLI (9%) (p = 0.001). Our comparisons suggest that the prophylactic use of DLI can significantly increase survival of patients with advanced‐stage, acute leukemia who receive HLA‐identical sibling HSCT.
Sperm competition roles and ejaculate investment in a promiscuous mammal
Authors: LEMAÎTRE J.‐F. , RAMM S. A. , HURST J. L. , STOCKLEY P. 
Published: April 2012

AbstractTheoretical models of sperm competition predict how males should allocate sperm and seminal fluid components to ejaculates according to their mating role (dominant vs. subordinate). Here, we present a detailed analysis of ejaculate expenditure according to male roles in the bank vole (Myodes glareolus). Sperm competition occurs regularly in this species, and dominant males typically achieve higher fertilization success than subordinates. Contrary to theoretical predictions, we found that dominant male bank voles invest more sperm per ejaculate than subordinates, both absolutely and relative to body and testes mass. The testes of dominant males were also absolutely (although not relatively) larger than those of subordinates. However, we found no evidence that subordinate males compensate for lower sperm numbers per ejaculate by increasing ejaculation frequency or sperm velocity. Similarly, we found no evidence for differential investment in copulatory plug size according to male roles in sperm competition, although dominant males had significantly larger seminal vesicles (both absolutely and relative to body mass) compared with subordinates. We conclude that sperm competition roles can have significant but unexpected influences on ejaculate investment in mammals with clearly defined differences in male social status.
Molecular Characterization of Stolbur Phytoplasma Associated with Pea Plants in Poland
Authors: Zwolińska Agnieszka , Krawczyk Krzysztof , Pospieszny Henryk 
Published: April 2012

AbstractPea plants (Pisum sativum) showing symptoms of stunting, shoot proliferation and leaf chlorosis were observed in 2008 during routine greenhouse cultivation of garden pea cultivars from commercially obtained seeds. The disease incidence occurred in over 25% of grown plants. To confirm phytoplasma infection, fresh tissue samples, from symptomatic and asymptomatic peas, were collected, and total DNA was extracted, using a modified CTAB method. Nested‐PCR assay was carried out with specific phytoplasma 16S rDNA primers: P1/P7 followed by R16F2n/R16R2. The product, of expected size 1.2 kb, was restricted with 6 different endonucleases, and on the basis of obtained RFLP profile, phytoplasma was identified as a 16Sr XII‐A ribosomal subgroup member. For further differentiation, the nucleotide sequence of the tuf gene encoding a transcription factor was analysed. This is the first report of phytoplasma affecting pea plants.
Patterns in the abundance of hyperbenthic zooplankton and colonization of marine benthic invertebrates on the seafloor of Saanich Inlet, a seasonally hypoxic fjord
Authors: Dinning Kristin M. , Metaxas Anna 
Published: April 2012

AbstractThis study describes changes in abundance of hyperbenthic zooplankton (including meroplankton) and benthic colonists at the seasonally hypoxic seabed of Saanich Inlet, British Columbia, Canada. We used the Victoria Experimental Network Under the Sea (VENUS) cabled observatory to measure water properties and to sample hyperbenthos with a sediment trap at 97 m from September 2008 to September 2009. Some faunal groups exhibited seasonal reproduction, and abundance peaked during their reproductive periods. These included larvae of the barnacle Balanus crenatus, and the crabs Petrolisthes eriomerus, Oregonia gracilis, and Lophopanopeus bellus bellus. Other groups were most abundant in spring and summer when food and oxygen levels were highest and temperature was lowest. These included cumaceans, the siphonophore Diphyes sp., the bryozoan Triticella pedicellata, and tintinnids. We also collected benthic colonists, predominantly bryozoans and polychaetes, on colonization plates deployed in spring/summer 2008, fall 2008/winter 2009, and spring/summer 2009. The total abundance of colonists and of bryozoans did not vary seasonally or with substrate complexity, whereas polychaetes were more numerous in spring/summer deployments and on a highly complex substrate. Taxon richness of colonists was higher in spring/summer 2008 than in fall 2008/winter 2009, whereas an anoxic episode in spring/summer 2009 reduced richness to similar values with that of fall 2008/winter 2009 levels. Substrate complexity had no effect on richness. Juvenile squat lobsters, digitally imaged in fall 2008/winter 2009, were most numerous when oxygen levels were lowest and potentially excluding larger predators. Our study illustrates how season, food availability, temperature, and oxygen can interact to shape community structure in a seasonally hypoxic habitat.
Vascular calcification in South African dialysis patients: Ethnic variation, prevalence, detection and haemodynamic correlates
Authors: FREERCKS ROBERT , SWANEPOEL CHARLES , CARRARA HENRI , MOOSA SULAIMAN , LACHMAN ANTHONY , RAYNER BRIAN 
Published: April 2012

ABSTRACT:Aim:  Studies from the US have shown little effect of ethnicity on vascular calcification in dialysis patients. This has not been examined in the multi‐ethnic population of South Africa where genetic and environmental differences may exist. We assessed the extent and severity of vascular calcification in South African dialysis patients according to race and known risk factors. We further evaluated the association of abdominal aorta calcification with coronary artery calcification.Method:  Seventy‐five CKD‐5D patients and 20 healthy controls were enrolled consecutively. All subjects underwent chest computed tomography for coronary calcium score and abdominal X‐ray for abdominal aorta calcium score. Ambulatory blood pressure monitoring was generated via radial artery applanation tonometry.Results:  Coronary calcification was present in 38.6% of patients and was associated with age and prior cardiovascular disease on multivariate analyses. The median coronary calcium score in black patients was 0 (IQR 0) and 66 in non‐Blacks (IQR 383, P < 0.001); controls had a coronary calcium score of 0 (IQR 0). Black race remained a significant negative predictor for coronary calcification after adjustment, prevalence ratio = 0.14 and 95% confidence interval (CI): 0.0–0.53. Vascular calcification was not associated with any ambulatory blood pressure parameter. Using receiver operator characteristic curves, an abdominal aorta calcification score of ≥1 showed an area under the curve of 0.83 to predict a coronary calcium score ≥ 10.Conclusion:  Black race appears to protect from vascular calcification in South African CKD‐5D patients and this warrants further study regarding the underlying mechanism. The abdominal X‐ray is a useful screening tool for coronary calcification.
The function of the wild carrot's dark central floret: attract, guide or deter?
Authors: POLTE SABRINA , REINHOLD KLAUS 
Published: April 2012

AbstractAlthough Charles Darwin wrote about flower polymorphism in the wild carrot, Daucus carota, the function of the conspicuous central dark floret is still unclear. We used video recordings to evaluate the functional significance of the dark central floret as a short‐distance signal for insects landing on the umbels and analyzed the location of landing points, landing orientation and visit duration. These parameters, as well as insect attraction did not differ on umbels with and without a dark central floret. Hence, we found no evidence for the role of the dark central floret in the pollination of D. carota. Umbels with a dark central floret, however, were parasitized significantly less often by the gall midge Kiefferia pericarpiicola than umbels without a dark central floret. We propose that the dark central floret may play a role in reducing parasite infestation by mimicking an already present gall or deterring oviposition of the gall midge by other means.
Analysis of the microbial gene landscape and transcriptome for aromatic pollutants and alkane degradation using a novel internally calibrated microarray system
Authors: Vilchez‐Vargas Ramiro , Geffers Robert , Suárez‐Diez María , Conte Ianina , Waliczek Agnes , Kaser Vanessa Sabrina , Kralova Monika , Junca Howard , Pieper Dietmar H. 
Published: April 2012

SummaryDespite various efforts to develop tools to detect and compare the catabolic potential and activity for pollutant degradation in environmental samples, there is still a need for an open‐source, curated and reliable array method. We developed a custom array system including a novel normalization strategy that can be applied to any microarray design, allowing the calculation of the reliability of signals and make cross‐experimental comparisons. Array probes, which are fully available to the scientific community, were designed from knowledge‐based curated databases for key aromatic catabolic gene families and key alkane degradation genes. This design assigns signals to the respective protein subfamilies, thus directly inferring function and substrate specificity. Experimental procedures were optimized using DNA of four genome sequenced biodegradation strains and reliability of signals assessed through a novel normalization procedure, where a plasmid containing four artificial targets in increased copy numbers and co‐amplified with the environmental DNA served as an internal calibration curve. The array system was applied to assess the catabolic gene landscape and transcriptome of aromatic contaminated environmental samples, confirming the abundance of catabolic gene subfamilies previously detected by functional metagenomics but also revealing the presence of previously undetected catabolic groups and specifically their expression under pollutant stress.
Imeglimin, a novel glimin oral antidiabetic, exhibits a good efficacy and safety profile in type 2 diabetic patients
Authors: Pirags V. , Lebovitz H. , Fouqueray P. 
Published: April 2012

Aims: Imeglimin is the first in a new tetrahydrotriazine‐containing class of oral antidiabetic agents, the glimins. It has been shown to act on the liver, muscle and pancreatic β‐cells to uniquely target the key defects of type 2 diabetes. Two studies were performed to compare the safety and efficacy of imeglimin with metformin and placebo on glycaemic control in type 2 diabetes patients.Methods: In a 4‐week phase IIa, three‐arm parallel group study, patients were randomized to imeglimin 2000 mg once daily (od), imeglimin 1000 mg twice daily (bid) or metformin 850 mg bid and responses to an oral glucose tolerance test (OGTT) were measured. In an 8‐week phase IIa, four‐arm controlled multi‐centre study, patients were randomized to imeglimin 500 mg bid, imeglimin 1500 mg bid, metformin 850 mg bid or placebo. Glycaemic assessments included area under the curve (AUC) up to 6 h (AUC0−6h) for glucose during a prolonged meal, fasting plasma glucose (FPG) and HbA1c. Safety and tolerability were assessed in both studies through adverse event recording and laboratory parameters, vital signs and electrocardiogram.Results: Imeglimin was found to be as effective as metformin at reducing the AUCPG and AUC0−6h, FPG and HbA1c. Imeglimin exhibited a favourable tolerability profile in comparison to metformin.Conclusions: The results from both studies confirm that imeglimin displays a superior benefit : risk profile compared with metformin in type 2 diabetes patients. The encouraging tolerability profile of imeglimin could make it suitable for combination with other classes of antidiabetic agents and may increase availability to a wider patient population.
Combined treatment with a dipeptidyl peptidase‐IV inhibitor (sitagliptin) and an angiotensin II type 1 receptor blocker (losartan) promotes islet regeneration via enhanced differentiation of pancreatic progenitor cells
Authors: Liang J. , Leung K. K. , Lam S. Y. , Leung P. S. 
Published: April 2012

Aim: The existence of pancreatic progenitor cells (PPCs) with differentiation capacity in the adult pancreas has rendered that promotion of islet regeneration is feasible. The dipeptidyl peptidase‐IV inhibitor sitagliptin and the angiotensin II type 1 receptor (AT1 receptor) blocker losartan have a common target action in the pancreata. Thus, we evaluated the synergistic/additive effects of these two drugs on the differentiation of islet progenitors.Methods: The acute and chronic effects of sitagliptin and losartan, individually or in combination, on islet regeneration in vivo were investigated by using a streptozotocin‐induced type 1 diabetes mouse model. Their effects were also examined on an in vitro PPCs model derived from human foetal pancreas.Results: A chronic combination treatment enhanced glucose tolerance in diabetic mice associated with an increased ratio of β cells to islet; an acute combination treatment resulted in a marked increase in the production of neurogenin 3 (NGN3+) cells in proximity to CK7+ ductal cell and an increased presence of insulin+/CK7+ cells. The in vitro study revealed that a combination treatment significantly enhanced mRNA expression of NGN3, NKX6.1 and PDX‐1 during PPCs differentiation into human islet‐like cell clusters (ICCs). Despite no apparent changes in insulin release, the combined treatment resulted in increasing production of peroxisome proliferator‐activated receptor γ (PPARγ) during PPC differentiation.Conclusions: These data indicate that combined sitagliptin–losartan treatment can improve islet function by promoting the differentiation of PPCs into ICCs, perhaps via a mechanism involving PPARγ production, and could thereby, contribute to islet regeneration.