bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic social behaviour in a bacterium:Pseudomonas aeruginosapartially compensates for siderophore loss to cheats
Authors: Harrison F.
Published: May 2013

Cooperation underlies diverse phenomena including the origins of multicellular life, human behaviour in economic markets and the mechanisms by which pathogenic bacteria cause disease. Experiments with microorganisms have advanced our understanding of how, when and why cooperation evolves, but the extent to which microbial cooperation can recapitulate aspects of animal behaviour is debated. For instance, understanding the evolution of behavioural response rules (how should one individual respond to another's decision to cooperate or defect?) is a key part of social evolution theory, but the possible existence of such rules in social microbes has not been explored. In one specific context (biparental care in animals), cooperation is maintained if individuals respond to a partner's defection by increasing their own investment into cooperation, but not so much that this fully compensates for the defector's lack of investment. This is termed ‘partial compensation’. Here, I show that partial compensation for the presence of noncooperating ‘cheats’ is also observed in a microbial social behaviour: the cooperative production of iron‐scavenging siderophores by the bacteriumPseudomonas aeruginosa. A period of evolution in the presence of cheats maintains this response, whereas evolution in the absence of cheats leads to a loss of compensatory behaviour. These results demonstrate (i) the remarkable flexibility of bacterial social behaviour, (ii) the potential generality of partial compensation as a social response rule and (iii) the need for mathematical models to explore the evolution of response rules in multi‐player social interactions.
Comparative pathogenicity study of ten different betanodavirus strains in experimentally infected European sea bass, Dicentrarchus labrax (L.)
Authors: Vendramin N , Toffan A , Mancin M , Cappellozza E , Panzarin V , Bovo G , Cattoli G , Capua I , Terregino C
Published: May 2013

Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a severe pathological condition caused by RNA viruses belonging to the Nodaviridae family, genus Betanodavirus. The disease, described in more than 50 fish species worldwide, is considered as the most serious viral threat affecting marine farmed species in the Mediterranean region, thus representing one of the bottlenecks for further development of the aquaculture industry. To date, four different genotypes have been identified, namely red‐spotted grouper nervous necrosis virus (RGNNV), striped jack nervous necrosis virus (SJNNV), tiger puffer nervous necrosis virus and barfin flounder nervous necrosis virus, with the RGNNV genotype appearing as the most widespread in the Mediterranean region, although SJNNV‐type strains and reassortant viruses have also been reported. The existence of these genetically different strains could be the reason for the differences in mortality observed in the field. However, very little experimental data are available on the pathogenicity of these viruses in farmed fish. Therefore, in this study, the pathogenicity of 10 isolates has been assessed with an in vivo trial. The investigation was conducted using the European sea bass, the first target fish species for the disease in the Mediterranean basin. Naive fish were challenged by immersion and clinical signs and mortality were recorded for 68 days; furthermore, samples collected at selected time points were analysed to evaluate the development of the infection. Finally, survivors were weighed to estimate the growth reduction. The statistically supported results obtained in this study demonstrated different pathogenicity patterns, underlined the potential risk represented by different strains in the transmission of the infection to highly susceptible species and highlighted the indirect damage caused by a clinical outbreak of VER/VNN.
Stroke‐Associated Differences in Rates of Activity of Daily Living Loss Emerge Years Before Stroke Onset
Authors: Capistrant Beatrix D. , Wang Qianyi , Liu Sze Y. , Glymour M. Maria
Published: May 2013

Objectives

To compare typical age‐related changes in activities of daily living (ADLs) independence in stroke‐free adults with long‐term ADL trajectories before and after stroke.

Design

Prospective, observational study.

Setting

Community‐dwelling Health and Retirement Study (HRS) cohort.

Participants

HRS participants who were stroke free in 1998 and were followed through 2008 (average follow‐up 7.9 years) (N = 18,441).

Measurements

Strokes were assessed using self‐ or proxy‐report of a doctor's diagnosis and month and year of event. Logistic regression was used to compare within‐person changes in odds of self‐reported independence in five ADLs in those who remained stroke free throughout follow‐up (n = 16,816), those who survived a stroke (n = 1,208), and those who had a stroke and did not survive to participate in another interview (n = 417). Models were adjusted for demographic and socioeconomic covariates.

Results

Even before stroke, those who later developed stroke had significantly lower ADL independence and were experiencing faster independence losses than similar‐aged individuals who remained stroke free. Of those who developed a stroke, survivors experienced slower pre‐stroke loss of ADL independence than those who died. ADL independence declined at the time of stroke and decline continued afterwards.

Conclusion

In adults at risk of stroke, disproportionate ADL limitations emerge well before stroke onset. Excess disability in stroke survivors should not be entirely attributed to effects of acute stroke or quality of acute stroke care. Although there are many possible causal pathways between ADL and stroke, the association may be noncausal. For example, ADL limitations may be a consequence of stroke risk factors (e.g., diabetes mellitus) or early cerebrovascular ischemia.
Consumption Volatility Risk
Authors: BOGUTH OLIVER , KUEHN LARS‐ALEXANDER
Published: May 2013

We show that time variation in macroeconomic uncertainty affects asset prices. Consumption volatility is a negatively priced source of risk for a wide variety of test portfolios. At the firm level, exposure to consumption volatility risk predicts future returns, generating a spread across quintile portfolios in excess of 7% annually. This premium is explained by cross‐sectional differences in the sensitivity of dividend volatility to consumption volatility. Stocks with volatile cash flows in uncertain aggregate times require higher expected returns.
THE SPATIOTEMPORAL EVOLUTION OF U.S. CARBON DIOXIDE EMISSIONS: STYLIZED FACTS AND IMPLICATIONS FOR CLIMATE POLICY
Authors: Baldwin James G. , Wing Ian Sue
Published: May 2013

We characterize the evolution of U.S. carbon dioxide (CO2) emissions using an index number decomposition technique which partitions the 1963–2008 growth of states’ energy‐related CO2into changes in five driving factors: the emission intensity of energy use, the energy intensity of economic activity, the composition of states’ output, per capita income and population. Compositional change and declining energy intensity attenuate emissions growth, but their impacts are offset by increasing population and income. Despite absolute interstate divergence in both emissions and their precursors, states’ emission‐ and energy intensities—and ultimately, CO2—appear to be stochastically converging. We assess the implications of these trends using a novel vector autoregression (VAR) emission forecasting technique based on our index numbers. The resulting emission projections are comparable to, but generally exceed, those forecast by the 2010 EIA Annual Energy Outlook.
Unusual manifestations of a common gastrointestinal disorder
Authors: Rajah Karthik , Oliver Mark R , McLeod Liz , Orchard David , Leal Marcelo
Published: May 2013

We present an instructive case of a 13‐year old male who presented with bilateral scrotal redness, swelling and tenderness, but with a normal testicular exam. His scrotal swelling persisted despite treatment with intravenous antibiotics, and on further history he reported 2 years of intermittent upper lip swelling. After a referral to a dermatologist, a lip biopsy showed granulomatous changes and he was referred to the gastroenterology department. A gastroscopy and colonoscopy was performed and histology confirmed non‐caseating granulomas consistent with Crohn's disease (CD). Eighteen months after the diagnosis of CD he developed perianal disease with a fistula and distal anal stricture. He was successfully treated with insertion of a seton and escalation of therapy to azathioprine and infliximab. CD is a phenotypically diverse chronic inflammatory condition with an increasing incidence in Australia and other Western countries. Non‐typical presentations, such as perianal manifestations or orofacial granulomatosis, can be the only presenting symptom in CD, and this highlights the importance for a high degree of clinical suspicion. Genital involvement is rare, but reported.
Evaluation of scaling and root planing effect in generalized chronic periodontitis by fractal and multifractal analysis
Authors: Pârvu A. E. , Ţălu Ş. , Crăciun C. , Alb S. F.
Published: May 2013

Background and Objective

Fractal and multifractal analysis are useful additional non‐invasive methods for quantitative description of complex morphological features. However, the quantitative and qualitative assessment of morphologic changes within human gingival cells and tissues are still unexplored. The aim of this work is to assess the structural gingival changes in patients with generalized chronic periodontitis (GCP), before and after scaling and root planing (SRP) by using fractal and multifractal analysis.

Material and Methods

Twelve adults with untreated chronic periodontitis were treated only by SRP. At baseline and after SRP, gingivomucosal biopsies were collected for histopathological examination. Fractal and multifractal analysis of digital images of the granular, spinous and basal and conjunctive layers structure, using the standard box‐counting method was performed. The fractal dimension was determined for cell membrane, nuclear membrane of cell and nucleolus membrane of cell.

Results

In GCP a higher fractal dimension corresponds to a higher geometric complexity of cells contour, as its values increase when the contour irregularities increase. The generalized fractal dimensions were determined for the conjunctive layer structure of patients with GCP and patients with GCP and SRP. The fractal and multifractal analysis of gingival biopsies confirmed earlier findings that SRP reduces gingival injury in patients with GCP.

Conclusion

It has been shown that fractal and multifractal analysis of tissue images as a non‐invasive technique could be used to measure contrasting morphologic changes within human gingival cells and tissues and can provide detailed information for investigation of healthy and diseased gingival mucosa from patients with GCP.
A novel framework for linking functional diversity of plants with other trophic levels for the quantification of ecosystem services
Authors: Lavorel Sandra , Storkey Jonathan , Bardgett Richard D. , de Bello Francesco , Berg Matty P. , Le Roux Xavier , Moretti Marco , Mulder Christian , Pakeman Robin J. , Díaz Sandra , Harrington Richard
Published: May 2013

A novel conceptual framework is presented that proposes to apply trait‐based approaches to predicting the impact of environmental change on ecosystem service delivery by multi‐trophic systems. Development of the framework was based on an extension of the response–effect trait approach to capture functional relationships that drive trophic interactions. The framework was populated with worked examples to demonstrate its flexibility and value for linking disparate data sources, identifying knowledge gaps and generating hypotheses for quantitative models.
Medical students' tobacco use and attitudes towards tobacco control
Authors: Do Young Kyung , Bautista Mary Ann
Published: May 2013

Context

Despite their important roles as future doctors in tobacco cessation counselling, the high prevalence of tobacco use among medical students may hinder them from advocating tobacco control policies and providing cessation counselling. Promoting this role among medical students is especially important in low‐ and middle‐income countries with high burdens of tobacco use but limited resources for cessation programmes. This study examined the associations between medical students' tobacco use and their attitudes towards tobacco control policies and the roles of health professionals in the provision of tobacco cessation advice.

Methods

This cross‐sectional study included data from the large multi‐country dataset generated by the Global Health Professions Student Survey, 2005−2008 (n = 36 533 medical students). Thirteen binary dependent variables related to medical students' attitudes towards tobacco control policies and the health professional's role in cessation counselling were examined using random‐effects logistic regression, with tobacco use status as the key explanatory variable. Covariates included gender, receipt of cessation training, country‐level and gender‐specific smoking prevalence, region, and country income group.

Results

Current tobacco use was consistently associated with less favourable attitudes towards tobacco control policy and cessation advice. Compared with never users, daily users were less likely to agree that the sale of tobacco products to adolescents should be banned (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.39−0.58) and that health professionals should routinely advise patients to quit smoking (OR = 0.48, 95% CI 0.41−0.52) or other forms of tobacco use (OR = 0.84, 95% CI 0.72−0.97). Daily users were less likely to agree that health professionals who smoke are less likely to advise patients to stop smoking (OR = 0.44, 95% CI 0.39–0.41).

Conclusions

Medical schools may benefit from a thorough re‐evaluation of the scope of tobacco cessation training in their curricula in order to support students in smoking cessation and to shape their attitudes towards tobacco control. Targeting medical students who are current tobacco users in tobacco control efforts may be beneficial, given the cost‐effectiveness of providing cessation advice.
Does student confidence on multiple‐choice question assessments provide useful information?
Authors: Curtis Donald A , Lind Samuel L , Boscardin Christy K , Dellinges Mark
Published: May 2013

Context

Feedback from multiple‐choice question (MCQ) assessments is typically limited to a percentage correct score, from which estimates of student competence are inferred. The students' confidence in their answers and the potential impact of incorrect answers on clinical care are seldom recorded. Our purpose was to evaluate student confidence in incorrect responses and to establish how confidence was influenced by the potential clinical impact of answers, question type and gender.

Methods

This was an exploratory, cross‐sectional study conducted using a convenience sample of 104 Year 3 dental students completing 20 MCQs on implant dentistry. Students were asked to select the most correct response and to indicate their confidence in it for each question. Identifying both correctness and confidence allowed the designation of uninformed (incorrect and not confident) or misinformed (incorrect but confident) responses. In addition to recording correct/incorrect responses and student confidence, faculty staff designated incorrect responses as benign, inappropriate or potentially harmful if applied to clinical care. Question type was identified as factual or complex. Logistic regression was used to evaluate relationships between student confidence, and question type and gender.

Results

Students were misinformed more often than uninformed (22% versus 8%), and misinformed responses were more common with complex than factual questions (p < 0.05). Students were significantly more likely to be confident of correct than incorrect benign, incorrect inappropriate or incorrect harmful answers (p < 0.001), but, contrary to expectations, confidence did not decrease as answers became more harmful.

Conclusions

Recording student confidence was helpful in identifying uninformed versus misinformed responses, which may allow for targeted remediation strategies. Making errors of calibration (confidence and accuracy) more visible may be relevant in feedback for professional development.
Beyond individualism: professional culture and its influence on feedback
Authors: Watling Christopher , Driessen Erik , van der Vleuten Cees P M , Vanstone Meredith , Lingard Lorelei
Published: May 2013

Context

Although feedback is widely considered essential to learning, its actual influence on learners is variable. Research on responsivity to feedback has tended to focus on individual rather than social or cultural influences on learning. In this study, we explored how feedback is handled within different professional cultures, and how the characteristics and values of a profession shape learners' responses to feedback.

Methods

Using a constructivist grounded theory approach, we conducted 12 focus groups and nine individual interviews (with a total of 50 participants) across three cultures of professional training in, respectively, music, teacher training and medicine. Constant comparative analysis for recurring themes was conducted iteratively.

Results

Each of the three professional cultures created a distinct context for learning that influenced how feedback was handled. Despite these contextual differences, credibility and constructiveness emerged as critical constants, identified by learners across cultures as essential for feedback to be perceived as meaningful. However, the definitions of credibility and constructiveness were distinct to each professional culture and the cultures varied considerably in how effectively they supported the occurrence of feedback with these critical characteristics.

Conclusions

Professions define credibility and constructiveness in culturally specific ways and create contexts for learning that may either facilitate or constrain the provision of meaningful feedback. Comparison with other professional cultures may offer strategies for creating a productive feedback culture within medical education.
Virtual patient design: exploring what works and why. A grounded theory study
Authors: Bateman James , Allen Maggie , Samani Dipti , Kidd Jane , Davies David
Published: May 2013

Objectives

Virtual patients (VPs) are online representations of clinical cases used in medical education. Widely adopted, they are well placed to teach clinical reasoning skills. International technology standards mean VPs can be created, shared and repurposed between institutions. A systematic review has highlighted the lack of evidence to support which of the numerous VP designs may be effective, and why. We set out to research the influence of VP design on medical undergraduates.

Methods

This is a grounded theory study into the influence of VP design on undergraduate medical students. Following a review of the literature and publicly available VP cases, we identified important design properties. We integrated them into two substantial VPs produced for this research. Using purposeful iterative sampling, 46 medical undergraduates were recruited to participate in six focus groups. Participants completed both VPs, an evaluation and a 1‐hour focus group discussion. These were digitally recorded, transcribed and analysed using grounded theory, supported by computer‐assisted analysis. Following open, axial and selective coding, we produced a theoretical model describing how students learn from VPs.

Results

We identified a central core phenomenon designated ‘learning from the VP’. This had four categories: VP Construction; External Preconditions; Student–VP Interaction, and Consequences. From these, we constructed a three‐layer model describing the interactions of students with VPs. The inner layer consists of the student's cognitive and behavioural preconditions prior to sitting a case. The middle layer considers the VP as an ‘encoded object’, an e‐learning artefact and as a ‘constructed activity’, with associated pedagogic and organisational elements. The outer layer describes cognitive and behavioural change.

Conclusions

This is the first grounded theory study to explore VP design. This original research has produced a model which enhances understanding of how and why the delivery and design of VPs influence learning. The model may be of practical use to authors, institutions and researchers.
Activity‐Based Travel Scenario Analysis with Routing Problem Reoptimization
Authors: Chow Joseph Y. J.
Published: May 2013

Activity‐based travel scenario analysis and network design using a household activity pattern problem (HAPP) can face significant computational cost and inefficiency. One solution approach, called reoptimization, makes use of an optimal solution of a prior problem instance to find a new solution faster and more accurately. Although the method is generally NP‐hard as well, the approximation bound has been shown in the literature to be tighter than a full optimization for several traveling salesman problem variations. To date, however, there have not been any computational studies conducted with the method for scenario analysis with generalized vehicle routing problems, nor has there been any metaheuristics designed with reoptimization in mind. A generalized, selective household activity routing problem (G‐SHARP) is presented as an extension of the HAPP model to include both destination and schedule choice for the purpose of testing reoptimization. Two reoptimization algorithms are proposed: a simple swap heuristic and a new class of evolutionary algorithms designed for reoptimization, dubbed a Genetic Algorithm with Mitochondrial Eve (GAME). The two algorithms are tested against a standard genetic algorithm in a computational experiment involving 100 zones that include 400 potential activities (resulting in a total of 802 nodes per single‐traveler household). Five hundred households are synthesized and computationally tested with a base scenario, a scenario where an office land use in one zone is dezoned, and a scenario where a freeway is added onto the physical network. The results demonstrate the effectiveness of reoptimization heuristics, particularly GAME, and the capability of G‐SHARP to capture reallocations of activities and schedules with respect to spatiotemporal changes.
Population structure of the mosquito Aedes aegypti (Stegomyia aegypti) in Pakistan
Authors: RASHEED S. B. , BOOTS M. , FRANTZ A. C. , BUTLIN R. K.
Published: May 2013

Eleven microsatellite markers were used to determine the genetic population structure and spread of Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) in Pakistan using mosquitoes collected from 13 different cities. There is a single genetic cluster of Ae. aegypti in Pakistan with a pattern of isolation by distance within the population. The low level of isolation by distance suggests the long‐range passive dispersal of this mosquito, which may be facilitated by the tyre trade in Pakistan. A decrease in genetic diversity from south to north suggests a recent spread of this mosquito from Karachi. A strong negative correlation between genetic distance and the quality of road connections shows that populations in cities connected by better road networks are less differentiated, which suggests the human‐aided passive dispersal of Ae. aegypti in Pakistan. Dispersal on a large spatial scale may facilitate the strategy of introducing transgenic Ae. aegypti or intracellular bacteria such as Wolbachia to control the spread of dengue disease in Pakistan, but it also emphasizes the need for simple measures to control container breeding sites.
Fenitrothion: an alternative insecticide for the control of deltamethrin‐resistant populations of Triatoma infestans in northern Argentina
Authors: GERMANO M. , PICOLLO M. I. , SPILLMANN C. , MOUGABURE‐CUETO G.
Published: May 2013

Deltamethrin‐based campaigns to control Triatoma infestans (Klug) (Hemiptera: Reduviidae) have decreased in success as a result of the development of insecticide resistance. We compared the in vitro effects of the pyrethroid deltamethrin and two doses of the organophosphate fenitrothion, presented on different materials, on T. infestans from La Esperanza, Argentina. Laboratory tests demonstrated a decrease in susceptibility to deltamethrin in the field population [LD50: 30.32 nanograms per insect (ng/i)] compared with the reference population (LD50: 0.13 ng/i), giving a high resistance ratio of 233.42. By contrast, similar susceptibility to fenitrothion was assessed in both the field and reference populations (LD50: 21.65 ng/i and 21.38 ng/i, respectively). The effectiveness of the formulated insecticides varied according to the surfaces to which they were applied. The application of fenitrothion formulations to glass or brick resulted in mortality of 90–100%. The application of fenitrothion formulations to wood or mud caused mortality in the range of 6.7–56.7%. Resistant insects presented low mortality when exposed to the deltamethrin formulation and high mortality when exposed to fenitrothion formulations. Moreover, the insecticides demonstrated residual activity only when applied to glass. The present work demonstrates that fenitrothion is an alternative to pyrethroids for the management of deltamethrin‐resistant insects in La Esperanza. However, this effectiveness is not sustained over time.
American rural women's exercise self‐efficacy and awareness of exercise benefits and safety during pregnancy
Authors: Melton Bridget , Marshall Elaine , Bland Helen , Schmidt Michael , Guion W. Kent
Published: May 2013

Though the positive link between physical activity and maternal health is well documented, physical activity declines during pregnancy and, internationally, rural mothers are less likely than urban mothers to engage in physical activity. Some evidence suggests that self‐efficacy is related to sustained engagement in physical activity. The purpose of this study was to examine self‐efficacy, perceived benefits, and knowledge of safe exercise among 88 rural pregnant women in a southeastern region of the United States. Exercise self‐efficacy was significantly related to maternal age and gestation. Women over age 26 years, and those in the second and third trimesters, scored significantly higher than younger women or those in the first trimester. Fifty‐two percent (n = 46) of participants perceived that activity would decrease energy levels, 37.5% (n = 33) did not know that exercise can decrease the risk of gestational diabetes, and 47.6% (n = 41) were unaware that a mother who is overweight is more likely to have an overweight child. Results confirm a need for education to improve women's knowledge about health benefits and safety information related to physical activity during pregnancy.
Bioengineering of plant (tri)terpenoids: from metabolic engineering of plants to synthetic biology in vivo and in vitro
Authors: Moses Tessa , Pollier Jacob , Thevelein Johan M. , Goossens Alain
Published: May 2013

Terpenoids constitute a large and diverse class of natural products that serve many functions in nature. Most of the tens of thousands of the discovered terpenoids are synthesized by plants, where they function as primary metabolites involved in growth and development, or as secondary metabolites that optimize the interaction between the plant and its environment. Several plant terpenoids are economically important molecules that serve many applications as pharmaceuticals, pesticides, etc. Major challenges for the commercialization of plant‐derived terpenoids include their low production levels in planta and the continuous demand of industry for novel molecules with new or superior biological activities. Here, we highlight several synthetic biology methods to enhance and diversify the production of plant terpenoids, with a foresight towards triterpenoid engineering, the least engineered class of bioactive terpenoids. Increased or cheaper production of valuable triterpenoids may be obtained by ‘classic’ metabolic engineering of plants or by heterologous production of the compounds in other plants or microbes. Novel triterpenoid structures can be generated through combinatorial biosynthesis or directed enzyme evolution approaches. In its ultimate form, synthetic biology may lead to the production of large amounts of plant triterpenoids in in vitro systems or custom‐designed artificial biological systems.

Contents

Summary
27

I.
Introduction
27

II.
‘Natural’ terpenoid biology
28

III.
‘Synthetic’ terpenoid biology
32

IV.
Perspectives: ‘exploration of triterpenoids: the road ahead’
38

Acknowledgements
40

References
40
NSP1 is a component of the Myc signaling pathway
Authors: Delaux Pierre‐Marc , Bécard Guillaume , Combier Jean‐Philippe
Published: May 2013

Summary

Nodulation and arbuscular mycorrhization require the activation of plant host symbiotic programs by Nod factors, and Myc‐LCOs and COs, respectively. The pathways involved in the perception and downstream signaling of these signals include common and distinct components. Among the distinct components, NSP1, a GRAS transcription factor, has been considered for years to be specifically involved in nodulation.

Here, we analyzed the degree of conservation of the NSP1 sequence in arbuscular mycorrhizal (AM) host and non‐AM host plants and carefully examined the ability of Medicago truncatula nsp1 mutants to respond to Myc‐LCOs and to be colonized by an arbuscular mycorrhizal fungus.

In AM‐host plants, the selection pressure on NSP1 is stronger than in non‐AM host ones. The response to Myc‐LCOs and the frequency of mycorrhizal colonization are significantly reduced in the nsp1 mutants.

Our results reveal that NSP1, previously described for its involvement in the Nod factor signaling pathway, is also involved in the Myc‐LCO signaling pathway. They bring additional evidence on the evolutionary relatedness between nodulation and mycorrhization.
Malignant odontogenic tumors: a multicentric latin american study of 25 cases
Authors: Martínez Martínez M , Mosqueda‐Taylor A , Carlos R , Delgado‐Azañero W , de Almeida OP
Published: May 2013

Objective

The aim of this study was to show the epidemiological features of 25 malignant odontogenic tumors (MOT) in Latin America.

Materials and Methods

We retrieved 25 cases of MOT out of 2142 odontogenic tumors, from four oral diagnostic centers in Latin America, and described the main clinical and pathological characteristics.

Results

A total of 19 cases were carcinomas, including eight ameloblastic carcinomas, five primary intra‐osseous squamous cell carcinomas, three clear cell odontogenic carcinomas and three ghost cell odontogenic carcinomas. All six sarcomas corresponded to ameloblastic fibrosarcoma. Thirteen cases occurred in men and 12 in women, age ranged from 7 to 77 years old, with a mean of 41.4 years. The average age of patients with carcinomas and sarcomas were 48.53 and 19 years old, respectively.

Conclusion

As malignant odontogenic tumors are very rare, this series helps to better clarify their relative frequency, predominant subtypes, and clinical characteristics in Latin America.
The time course of blur adaptation in emmetropes and myopes
Authors: Khan Kiren A , Dawson Katherine , Mankowska Aleksandra , Cufflin Matthew P , Mallen Edward AH
Published: May 2013

Purpose/Background

This study examined the effect of myopic defocus on visual acuity (VA) over time, with attention being paid to the first point at which blur adaptation had a significant and measurable effect on defocused VA. Visual acuity was sampled at a higher rate than previous studies in order to assess the time course of blur adaptation processes in myopic and emmetropic observers.

Methods

Participants were 24 normally‐sighted observers (12 emmetropes and 12 myopes, median age: 22.5 years). All ametropic participants wore their full refractive correction throughout the experiment. 1 D and 3 D of myopic defocus were introduced in two separate, randomised sessions. Visual acuity was measured using Test Chart 2000 at 2 min intervals over a 30 min session whilst looking through defocus lenses. Recovery clear VA was also measured every 2 min for a further 20 min.

Results

Defocused VA was found to improve significantly within 4 min after the introduction of defocus for both 1 D (P < 0.0001) and 3 D conditions (P < 0.0001). The improvements reached a plateau shortly after, with no significant further improvements in defocused VA after 6 min. There were no significant differences found in the temporal blur adaptation profiles between emmetropes and myopes (P = 0.267). Data were fitted with an exponential decay function; the lowest R2 value for this fit was 0.95.

Conclusions

Blur adaptation has a clinically significant and measurable effect on VA within 4 min of exposure to defocus. This finding indicates that the visual system instigates the neural compensatory mechanisms shortly after the appearance of defocus. Our results relate particularly to real‐life vision of uncorrected myopes or myopes who remove their correction for part of the day.
Relative peripheral refraction in children: twelve‐month changes in eyes with different ametropias
Authors: Lee Tsui‐Tsui , Cho Pauline
Published: May 2013

Purpose

To determine the peripheral refraction of children with different types of ametropias and to evaluate the relationship between central refractive changes, baseline relative peripheral refraction (RPR) and changes in RPR over a 12‐month monitoring period.

Methods

Cycloplegic central and peripheral refraction were performed biannually on the right eyes of children aged 6–9 for 12 months, using an open‐view autorefractor. Peripheral refraction were measured along 10°, 20° and 30° from central fixation in both nasal and temporal fields. Refractive data were transposed into M, J0 and J45 vectors for analyses. RPR was determined by subtracting the central measurement from each peripheral measurement.

Results

Hyperopic eyes showed relative peripheral myopia while myopic eyes had relative hyperopia across the central 60° horizontal field at baseline. Emmetropic eyes had relative myopia within but showed relative hyperopia beyond the central 30° field. However, there was no significant correlation between central refractive changes and baseline RPR or between changes in central refraction and RPR over twelve months in any refractive groups. Correlations between changes in PR and central myopic shift were found mainly in the nasal field in different groups. In the subgroup analysis on the initially emmetropic and the initially myopic groups, the subgroups with faster myopic progression did not have significantly different RPR from the subgroups with slower progression. The RPR pattern of the initially emmetropic and the initially myopic groups became more asymmetric at the end of the study period with a larger increase in relative hyperopia in the temporal field.

Conclusions

RPR patterns were different among hyperopic, emmetropic and myopic eyes. However, baseline RPR and changes in RPR cannot predict changes in central refraction over time. Our results did not provide evidence to support the hypothesis of RPR as a causative factor for myopic central refractive changes in children.
Zernike vs. Bessel circular functions in visual optics
Authors: Trevino Juan P , Gómez‐Correa Jesus E , Iskander D Robert , Chávez‐Cerda Sabino
Published: May 2013

Purpose

We propose the Bessel Circular Functions as alternatives of the Zernike Circle Polynomials to represent relevant circular ophthalmic surfaces.

Methods

We assess the fitting capabilities of the orthogonal Bessel Circular Functions by comparing them to Zernike Circle Polynomials for approximating a variety of computationally generated surfaces which can represent ophthalmic surfaces.

Results

The Bessel Circular Functions showed better modelling capabilities for surfaces with abrupt variations such as the anterior eye surface at the limbus region, and influence functions. From our studies we find that the Bessel Circular Functions can be more suitable for studying particular features of post surgical corneal surfaces.

Conclusions

We show that given their boundary conditions and free oscillating properties, the Bessel Circular Functions are an alternative for representing specific wavefronts and can be better than the Zernike Circle Polynomials for some important cases of corneal surfaces, influence functions and the complete anterior corneal surface.
Cardioprotective effect of remote ischemic postconditioning on children undergoing cardiac surgery: a randomized controlled trial
Authors: Zhong Haixing , Gao Zijun , Chen Min , Zhao Jing , Wang Feng , Li Liya , Dong Hailong , Liu Lixin , Wang Qiang , Xiong Lize
Published: May 2013

Background

Remote ischemic postconditioning (RPostC) is a noninvasive intervention that has demonstrated cardioprotection and neuroprotection in animal studies.

Objective

Our goal was to investigate the cardio‐cerebral protective effects of RPostC on children undergoing open‐heart surgery for repair of congenital heart defects (CHD).

Methods

Children undergoing open‐heart repair of CHD were randomly assigned to a RPostC or control group. RPostC was induced by three 5‐min cycles of lower limb ischemia and reperfusion using a blood pressure cuff (200 mmHg) at the onset of aortic unclamping. Serum cardiac troponin I (cTnI), creatine kinase‐MB (CK‐MB), neuron‐specific enolase (NSE), S100β, cytokines, and clinical outcomes were assessed.

Results

There were 35 children in the control group and 34 in the RPostC group. The mean age (3.64 ± 1.95 years vs. 3.45 ± 3.02 years, P = 0.80), weight (15.11 ± 6.91 kg vs. 13.40 ± 6.33 kg, P = 0.37), surgical time (144.82 ± 38.51 min vs. 129.92 ± 30.76 min, P = 0.15), and bypass time (78.01 ± 27.22 min vs. 72.52 ± 26.05 min, P = 0.49) were not different. Compared with the control group, the postoperative levels of cTnI (P = 0.037) and CK‐MB (P = 0.046) were significantly reduced in the RPostC group. Furthermore, the MAP was higher (P = 0.008), and ICU stay (36.87 ± 3.30 h vs. 60.57 ± 7.35 h, P = 0.006) and postoperative hospital stay (8.56 ± 1.50 days vs. 10.06 ± 2.41 days, P = 0.048) were shorter in the RPostC group than in the control group. However, the postoperative CVP and the concentrations of NSE, S100β, CRP, TNF‐α, IL‐1β, IL‐6, and IL‐10 were not significantly different.

Conclusion

RPostC significantly alleviates cardiac injury in children undergoing open‐heart repair of CHD and may also reduce cerebral injury.
Experimental evidence for diel δ15N‐patterns in different tissues, xylem and phloem saps of castor bean (Ricinus communis L.)
Authors: PEUKE A. D. , GESSLER A. , TCHERKEZ G.
Published: May 2013

Nitrogen isotope signatures in plants might give insights in the metabolism and allocation of nitrogen. To obtain a deeper understanding of the modifications of the nitrogen isotope signatures, we determined δ15N in transport saps and in different fractions of leaves, axes and roots during a diel course along the plant axis. The most significant diel variations were observed in xylem and phloem saps where δ15N was significantly higher during the day compared with during the night. However in xylem saps, this was observed only in the canopy, but not at the hypocotyl positions. In the canopy, δ15N was correlated fairly well between phloem and xylem saps. These variations in δ15N in transport saps can be attributed to nitrate reduction in leaves during the photoperiod as well as to 15N‐enriched glutamine acting as transport form of N. δ15N of the water soluble fraction of roots and leaves partially affected δ15N of phloem and xylems saps. δ15N patterns are likely the result of a complex set of interactions and N‐fluxes between plant organs. Furthermore, the natural nitrogen isotope abundance in plant tissue is not constant during the diel course – a fact that needs to be taken into account when sampling for isotopic studies.
The State(s) of Health: Federalism and the Implementation of Health Reform in the Context of HIV Care
Authors: Martin Erika G. , Strach Patricia , Schackman Bruce R.
Published: May 2013

Although the federal government will finance most of the coverage expansions of the Patient Protection and Affordable Care Act (ACA), implementation is largely devolved to states. Drawing from interviews with HIV policy experts and program managers and a documents review, the authors enumerate actions that must occur at multiple levels of government in order for ACA implementation in the context of HIV care to improve access to health care and health outcomes and the conditions under which these may fall short. Positive outcomes are predicted for HIV patients in states with sufficient political support and resources to implement the ACA. However, outcomes may worsen in states that do not implement the Medicaid expansion or other ACA provisions, particularly if federal funding for discretionary safety net programs is reduced. Transitioning patients from HIV‐specific programs to other coverage sources may also reduce HIV services in states that previously were at the forefront of HIV care.
Proliferating cell nuclear antigen and Vasa protein expression during gonadal development and sexual differentiation in cultured Siberian (Acipenser baerii Brandt, 1869) and Russian (Acipenser gueldenstaedtii Brandt & Ratzeburg, 1833) sturgeon
Authors: Rzepkowska Malgorzata , Ostaszewska Teresa
Published: May 2013

Early gonadal development in Russian (Acipenser gueldenstaedtii Brandt, 1869) and Siberian sturgeon (Acipenser baerii Brandt & Ratzeburg, 1833) reared in controlled conditions from dph 1–439 (days post hatching) was studied using histological methods. Migrating primordial germ cells (PGCs) were observed in both species on dph 1. On dph 25 in both species gonad primordia developed in gonadal ridges. In dph 115 juveniles two types of gonad were distinguished, putative ovary and putative testicle. Meiotic activity was observed in ovaries on dph 197, while in testicles the first meiotic divisions were observed much later, on dph 439 and only in several Siberian specimens. The presence of Vasa protein was confirmed exclusively in germ cells during gonadogenesis, indicating that Vasa is a good marker of germinal cells also in Acipenseridae. Vasa protein displayed a nuage association or nuage‐like localization. Some differences in the level of Vasa protein expression during male and female gonad development were also observed. In the gonads of both investigated sturgeon species the PCNA (proliferating cell nuclear antigen)‐positive reaction was observed first in oogonia, while in spermatogonia at approximately 115 dph which was correlated with active mitotic divisions of germ cells. Surprisingly, meiotic oocytes arrested in diplotene also demonstrated strong PCNA‐positive germinal vesicle.
Influence of Toll‐Like Receptor Gene Polymorphisms to Tuberculosis Susceptibility in Humans
Authors: Thada S. , Valluri V. L. , Gaddam S. L.
Published: May 2013

Tuberculosis (TB) is caused by Mycobacterium tuberculosis (M. tb), and it remains one of the major bacterial infections worldwide. Innate immunity is an important arm of antimycobacterial host defence mechanism that senses various pathogen‐associated molecular patterns (PAMP) of microbes by a variety of pattern recognition receptors (PRRs). As per the recent discovery, Toll‐like receptors (TLRs) play a crucial role in the recognition of M. tb, this immune activation occurs only in the presence of functional TLRs. Variants of TLRs may influence their expression, function and alters the recognition or signalling mechanism, which leads to the disease susceptibility. Hence, the identification of mutations in these receptors could be used as a marker to screen the individuals who are at risk. In this review, we discuss TLR SNPs and their signalling mechanism to understand the susceptibility to TB for better therapeutic approaches.
Social problem‐solving, perceived stress, depression and life‐satisfaction in patients suffering from tension type and migraine headaches
Authors: Eskin Mehmet , Akyol Ali , Çelik Emine Yilmaz , Gültekin Bülent Kadri
Published: May 2013

This study aimed at investigating social problem solving, perceived stress, depression, and life‐satisfaction in patients with tension type and migraine headaches. Forty‐nine migraine and 42 tension type headache patients (n = 91) consenting to participate were compared to a total of 49 matched healthy control group. Participants filled in a questionnaire consisting self‐report measures of problem solving, perceived stress, depression and life satisfaction. They were also asked about headache duration, frequency, pain severity, psychiatric treatment and sense of control in one's life. T‐tests, chi‐square, analysis of variance, logistic regression analysis and Pearson product moment correlation coefficient procedures were used to analyze the data. Tension type headache patients reported having had more frequent headaches than the migraine patients but migraine patients reported having had more intense pain than the tension type headache patients. Instances of psychiatric treatment were more common among tension type headache patients than the migraine and the control group. Compared to the healthy controls, headache patients displayed a deficiency in problem solving, higher levels of perceived stress and depression. Levels of problem solving skills in headache patients were related inversely to depression, perceived stress and the number of negative life events but problem solving skills of headache patients was related positively to life‐satisfaction. The findings from this study suggested that cognitive behavioral problem solving therapy or training might be a viable option for reducing levels of stress and depression, and to increase life‐satisfaction in patients suffering from primary headache.
Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31P‐MRS
Authors: Yoshida T. , Abe D. , Fukuoka Y.
Published: May 2013

To investigate the high‐energy phosphate metabolism by 31P‐nuclear magnetic resonance spectroscopy during off‐transition of exercise in different muscle groups, such as calf muscles and biceps femoris muscles, seven male long‐distance runners (LDR) and nine untrained males (UT) performed both submaximal constant and incremental exercises. The relative exercise intensity was set at 60% of the maximal work rate (60%Wmax) during both knee flexion and plantar flexion submaximal constant load exercises. The relative areas under the inorganic phosphate (Pi) and phosphocreatine (PCr) peaks were determined. During the 5‐min recovery following the 60%Wmax, the time constant for the PCr off‐kinetics was significantly faster in the plantar flexion (LDR: 17.3 ± 3.6 s, UT: 26.7 ± 6.7 s) than in the knee flexion (LDR: 29.7 ± 4.7 s, UT: 42.7 ± 2.8 s, P < 0.05). In addition, a significantly faster PCr off‐kinetics was observed in LDR than in UT for both exercises. The ratio of Pi to PCr (Pi/PCr) during exercise was significantly lower during the plantar flexion than during the knee flexion (P < 0.01). These findings indicated that the calf muscles had relatively higher potential for oxidative capacity than that of biceps femoris muscles with an association of training status.