bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of GABAergic inhibition in shaping the spatial frequency tuning of neurons and its contrast dependency in the dorsal lateral geniculate nucleus of cat
Authors: Kimura Akihiro , Shimegi Satoshi , Hara Shin'ichiro , Okamoto Masahiro , Sato Hiromichi 
Published: February 2013

AbstractTo understand how GABAergic inhibition contributes to the elaboration of spatial frequency (SF) tuning of neurons in the lateral geniculate nucleus, we examined the effects of the microiontophoretic administration of bicuculline methiodide (BIC) and gabazine, both antagonists of GABAA receptors, on visual responses to grating stimuli with high or low contrasts. BIC administration changed the shape of the SF tuning curve of the spike response from band‐pass to low‐pass. We took the tuning curve obtained under the BIC condition as an estimated excitatory contribution to the control tuning curve and then estimated the difference between tuning curves recorded with and without BIC as the tuning curve of the estimated GABAergic inhibitory contribution. The SF tuning profile of estimated inhibition (Estimated‐Inh) varied widely from cell to cell, as did estimated excitation (Estimated‐Ex). Nonetheless, the relationship that Estimated‐Inh exhibited more low‐pass tuning than did Estimated‐Ex was well conserved in the majority of cells, and the relationship refined the SF tuning of Estimated‐Ex toward the band‐pass tuning of the geniculate output. Lowering the stimulus contrast decreased the response magnitude, but did not change the degree of band‐pass tuning. The GABAergic refinement of the SF tuning was also observed at low stimulus contrast, but was weaker than at high contrast, suggesting that GABAergic inhibition is regulated in coordination with excitatory inputs to keep the degree of the band‐pass tuning constant. We therefore concluded that the degree of band‐pass tuning is conserved contrast invariantly in the lateral geniculate nucleus on the basis of the dynamic regulatory action of GABAergic inhibition.
Behavioural Responses of European Roe Deer to Temporal Variation in Predation Risk
Authors: Sönnichsen Leif , Bokje Matthijs , Marchal Jessica , Hofer Heribert , Jędrzejewska Bogumiła , Kramer‐Schadt Stephanie , Ortmann Sylvia 
Published: February 2013

AbstractIn natural environments, predation risk varies over time. The risk allocation hypothesis predicts that prey is expected to adjust key anti‐predator behaviours such as vigilance to temporal variation in risk. We tested the predictions of the risk allocation hypothesis in a natural environment where both a species‐rich natural predator community and human hunters are abundant and where the differences in seasonal and circadian activity between natural and anthropogenic predators provided a unique opportunity to quantify the contributions of different predator classes to anti‐predator behaviour. Whereas natural predators were expected to show similar levels of activity throughout the seasons, hunter activity was high during the daytime during a clearly defined hunting season. According to the risk allocation hypothesis, vigilance should then be higher during the hunting season and during daytime hours than during the non‐hunting season and night‐time hours. Roe deer (Capreolus capreolus) on the edge of Białowieża Primeval Forest in Eastern Poland displayed vigilance behaviour consistent with these predictions. The behavioural response of roe deer to temporarily varying predation risks emphasises the behavioural plasticity of this species and suggests that future studies of anti‐predator behaviour need to incorporate circadian variation in predation pressure as well as risk gradients of both natural and anthropogenic predators.
Effects of metformin hydrochloride on blood glucose and insulin responses to oral dextrose in horses
Authors: Rendle D. I. , Rutledge F. , Hughes K. J. , Heller J. , Durham A. E. 
Published: February 2013

SummaryReasons for performing studyMetformin is a potential therapeutic agent for the treatment of insulin resistance (IR). In laboratory animals, orally administered metformin reduces intestinal glucose absorption and may therefore affect insulinaemic responses to oral carbohydrate ingestion.ObjectivesTo determine whether pretreatment with metformin reduces plasma glucose concentration and insulin responses following consumption of dextrose in horses.Study designTherapeutic cross‐over study.MethodsSeven healthy Standardbred and Thoroughbred geldings were subjected to an oral dextrose challenge test on 4 occasions: with and without metformin, before and after induction of IR with dexamethasone. Metformin was administered by nasogastric tube at 30 mg/kg bwt 1 h before administration of dextrose. Glucose and insulin concentrations in plasma/serum were measured at regular intervals during each test. Linear mixed models were specified for each predetermined outcome variable, and for each model the ‘treatment’ was included as a fixed effect with 4 categorical levels (none, metformin, dexamethasone and dexamethasone with metformin) and horse accounted for as a random effect.ResultsIn healthy horses, the administration of metformin resulted in a statistically significant reduction in peak glucose concentration (P = 0.002), area under the glucose curve (P<0.001) and insulin concentration 120 min after dextrose administration (P = 0.011). Following the induction of IR, administration of metformin was associated with significant differences in peak glucose concentration (P<0.001), the percentage increase in glucose concentration (P = 0.010), the area under the glucose curve (P<0.001) and insulin concentration at 120 min (P = 0.034) and 150 min after dextrose administration (P = 0.014).ConclusionsMetformin resulted in reduced glycaemic and insulinaemic responses both in healthy horses and in horses with experimentally induced IR.Potential relevanceMetformin may benefit horses with naturally acquired IR by reducing glycaemic and insulinaemic responses to dietary nonstructural carbohydrates. Further investigations into the mechanisms of action of metformin in horses and controlled clinical trials are warranted.
Fatigue strength assessment of laser stake‐welded web‐core steel sandwich panels
Authors: Frank D. , Romanoff J. , Remes H. 
Published: February 2013

ABSTRACTThis paper investigates the fatigue strength assessment of web‐core steel sandwich panels. The production of these structures is made possible by laser stake welding. The investigation in this study considered two series of panels, one being an empty steel structure and the other filled with in situ polyurethane foam in order to increase the panel stiffness. Both series were tested under cyclic bending loading condition (R = 0) until one of the panel joints failed completely. A 3D panel bending response was analysed using finite element method. The J‐integral values at the panel joints were obtained by means of plane strain finite element analysis and by using displacements from 3D panel response. The influence of the weld geometry on the J‐integral value was investigated. It was found that the J‐integral value is similar in the cases of the average and critical geometry. The contact between the joint plates is possible in some cases, but its influence proved to be insignificant for the fatigue strength assessment. The study further shows that by using the average geometry, the J‐integral approach was able to identify the critical panel joints and present the fatigue strength results from both panel series in a narrow scatterband. The fatigue strength at two million cycles obtained for the panels within this study was in agreement with the laser stake welds and other steel joint types from previous studies. However, the slope of the panels fatigue resistance curve was found to be shallower than in the case of joints.
The influence of coarse‐scale environmental features on current and predicted future distributions of narrow‐range endemic crayfish populations
Authors: DYER JOSEPH J. , BREWER SHANNON K. , WORTHINGTON THOMAS A. , BERGEY ELIZABETH A. 
Published: February 2013

Summary1. A major limitation to effective management of narrow‐range crayfish populations is the paucity of information on the spatial distribution of crayfish species and a general understanding of the interacting environmental variables that drive current and future potential distributional patterns.2. Maximum Entropy Species Distribution Modeling Software (MaxEnt) was used to predict the current and future potential distributions of four endemic crayfish species in the Ouachita Mountains. Current distributions were modelled using climate, geology, soils, land use, landform and flow variables thought to be important to lotic crayfish. Potential changes in the distribution were forecast by using models trained on current conditions and projecting onto the landscape predicted under climate‐change scenarios.3. The modelled distribution of the four species closely resembled the perceived distribution of each species but also predicted populations in streams and catchments where they had not previously been collected. Soils, elevation and winter precipitation and temperature most strongly related to current distributions and represented 65–87% of the predictive power of the models. Model accuracy was high for all models, and model predictions of new populations were verified through additional field sampling.4. Current models created using two spatial resolutions (1 and 4.5 km2) showed that fine‐resolution data more accurately represented current distributions. For three of the four species, the 1‐km2 resolution models resulted in more conservative predictions. However, the modelled distributional extent of Orconectes leptogonopodus was similar regardless of data resolution. Field validations indicated 1‐km2 resolution models were more accurate than 4.5‐km2 resolution models.5. Future projected (4.5‐km2 resolution models) model distributions indicated three of the four endemic species would have truncated ranges with low occurrence probabilities under the low‐emission scenario, whereas two of four species would be severely restricted in range under moderate–high emissions. Discrepancies in the two emission scenarios probably relate to the exclusion of behavioural adaptations from species‐distribution models.6. These model predictions illustrate possible impacts of climate change on narrow‐range endemic crayfish populations. The predictions do not account for biotic interactions, migration, local habitat conditions or species adaptation. However, we identified the constraining landscape features acting on these populations that provide a framework for addressing habitat needs at a fine scale and developing targeted and systematic monitoring programmes.
The Secretome of Helicobacter Trogontum
Authors: Kaakoush Nadeem O. , Sirianni Andrea , Raftery Mark J. , Mitchell Hazel M. 
Published: February 2013

AbstractBackgroundHelicobacter trogontum is a putative enterohepatic pathogen, which following infection of IL‐10 knock‐out mice, results in severe clinical signs and typhlocolitis.Materials and MethodsThe pathogenic potential of H. trogontum Type strain LRB 8581 was investigated using proteomics coupled with mass spectrometry to characterize the secretome of H. trogontum and scanning electron microscopy to visualize H. trogontum adherence and invasion.ResultsOne hundred and four proteins were identified and bioinformatically predicted to be secreted. Further functional classifications revealed proteins involved in motility, virulence, and colonization factors and the type VI secretion system. Microscopy showed that H. trogontum can adhere to host cells through flagella–microvillus interactions and invade causing a membrane ruffling‐like effect and severe cell damage.ConclusionsThis indicated H. trogontum has the ability to adhere to and invade human cells and secrete factors that may contribute to disease development.
Beyond UV radiation: A skin under challenge
Authors: Dupont E. , Gomez J. , Bilodeau D. 
Published: February 2013

SynopsisSince ancient times, human beings have been trying to protect their skin against the adverse effects of the sun. From the first mineral sunscreens used by Egyptians, to the current more sophisticated ultraviolet (UVA/UVB) organic sunscreens, progress has been made in terms of sun protection and deeper knowledge of skin physiology has been acquired in the process. The solar spectrum is composed of radiations of various wavelengths having specific, as well as overlapping effects on skin. UVB is mainly responsible for sunburn and DNA dimer formation that can lead to mutation. UVA generates oxidative reactions affecting DNA, proteins and lipids, and is also immunosuppressive. Recently, visible light and infrared radiation (IR) have been associated with oxidative damage and IR has been additionally linked to adverse heat effects on skin. Numerous other extrinsic factors, related to environment and lifestyle, also affect the appearance of skin, precipitating ageing. New molecular mechanisms linking sun and environmental factors to skin ageing have been identified: IR affects mitochondrial integrity and specific heat receptors also mediate some of its effects, tryptophan is a chromophore for UVB, and the aryl hydrocarbon receptor (AhR) is activated by light and xenobiotics to alter skin physiology. Integrating all these new elements is changing the way we think about skin extrinsic ageing. Is UVA/UVB sunscreen protection still enough for our skin?
‘Popper'‐induced vision loss
Authors: Krilis Matthew , Thompson Julia , Atik Alp , Lusthaus Jed , Jankelowitz Stacey 
Published: February 2013

AbstractAmyl nitrite ‘poppers’ are recreational drugs, which are a potent source of nitric oxide. The use of ‘poppers’ can cause psychoactive stimulation, reduced blood pressure, tachycardia and involuntary muscle relaxation. Their use is becoming increasingly common around the world, including approximately 60% of Australia's male homosexual community. We report the first case of ‘popper'‐induced vision loss in Australasia.
What's in a name? The importance of definition and comparable data
Authors: Baumann Andrea 
Published: February 2013

BackgroundThe advent of a more planned approach to workforces has led to increased interest in knowing exactly what workforces do, how much they cost and who their members are. Heightened interest in health human resources has highlighted the need for accurate definitions of nurse and nursing role and emphasized the importance of accurate, valid and timely workforce data.AimThis commentary addresses some of the statements made in this issue by Currie and Carr‐Hill (pp. 67–74) who ask, ‘What is a nurse? Is there an international consensus?’ General remarks about the importance of nursing health services data are also provided.DiscussionIt is not surprising that nursing is struggling with standardization of definitions and role descriptions within and across countries. Globalization has intensified the need to understand complex relationships between systems such as education, finance and health that often differ from country to country.ConclusionProfessional and/or regulatory nursing associations can facilitate standardization of definitions and strengthen data collection; both of which are imperative. The more titles we create, the more difficult it becomes to have a generalized taxonomy of nursing services locally, nationally and internationally. Working closely with agencies like the International Council of Nurses and the World Health Organization may lead to a much‐needed consensus on common indicators within and across countries. Given the large size of the nursing workforce worldwide, nurses can play an important role in the creation of comparable data that can be used to set policies that will affect the delivery of quality health care.
Growing Up at the “Margins”: Concerns, Aspirations, and Expectations of Young People Living in Nairobi's Slums
Authors: Kabiru Caroline W. , Mojola Sanyu A. , Beguy Donatien , Okigbo Chinelo 
Published: February 2013

We explore the concerns, challenges, aspirations, and expectations of sub‐Saharan African youth, and investigate how these youth cope with neighborhood constraints to aspiration achievement. We draw on cross‐sectional survey data from 4033 12–22‐year‐olds (50.3% males) from two Kenyan urban slums and subsequent in‐depth interviews conducted with a subset of 75 youth when they were 13–24 years old (45.3% males). We observe that despite the challenges characteristic of urban slums, some youth maintain high aspirations and try to achieve them through education, delinquency, residential mobility, and religion. We note that others adjust their aspirations to account for limited opportunities. Overall, our findings highlight positive youth agency and underscore the need to improve the quality of life in urban slums.
Linking Life Skills and Norms With Adolescent Substance Use and Delinquency in South Africa
Authors: Lai Mary H. , Graham John W. , Caldwell Linda L. , Smith Edward A. , Bradley Stephanie A. , Vergnani Tania , Mathews Cathy , Wegner Lisa 
Published: February 2013

We examined factors targeted in two popular prevention approaches with adolescent drug use and delinquency in South Africa. We hypothesized adolescent life skills to be inversely related and perceived norms to be directly related to later drug use and delinquency. Multiple regression and a relative weights approach were conducted for each outcome using a sample of 714 South African adolescents aged 15–19 years (M = 15.8 years, 57% female adolescents). Perceived norms predicted gateway drug use. Conflict resolution skills (inversely) and perceived peer acceptability (directly) predicted harder drug use and delinquency. The “culture of violence” within some South African schools may make conflict resolution skills more salient for preventing harder drug use and delinquency.
Pension Conversion, Termination, and Wealth Transfers
Authors: Harper Joel T. , Treanor Stephen D. 
Published: February 2013

AbstractThis article explores the motivation to change their defined benefit pension plan by either terminating the plan and replacing it with a defined contribution plan or converting it to a cash balance plan. Using Form 5500 data as well as firm financial data, we find firms wishing to change their defined benefit plans are motivated by potential wealth transfer and tax implications. Firms terminating pension plans tend to have lower potential wealth transfers and lower taxes than firms converting to a cash balance plan, indicating a desire to modify the implicit contract instead of terminating the plan.
Typhoons and Opportunistic Fraud: Claim Patterns of Automobile Theft Insurance in Taiwan
Authors: Pao Tsung‐I , Tzeng Larry Y. , Wang Kili C. 
Published: February 2013

AbstractWe present evidence to support the existence of opportunistic fraud in the automobile theft insurance market in Taiwan. After encountering a typhoon hit, the insured who purchase automobile theft insurance but do not purchase typhoon/flood insurance tend to have a significantly higher probability of filing a total theft claim than other insured. The above relationship exists mainly in places affected by typhoons. Such evidence does not exist in partial theft claim. These claim patterns of automobile theft insurance provide us with strong evidence that supports the existence of opportunistic fraud in the market.
Identification and comparison of insulin pharmacokinetics injected with a new 4‐mm needle vs 6‐ and 8‐mm needles accounting for endogenous insulin and C‐peptide secretion kinetics in non‐diabetic adult males
Authors: Hirose Takahisa , Ogihara Takeshi , Tozaka Shusaku , Kanderian Sami , Watada Hirotaka 
Published: February 2013

AbstractAims/IntroductionMany patients with diabetes now use 5‐, 6‐ or 8‐mm needles for insulin injection. However, it is unclear whether needle length, particularly for shorter needles, affects the pharmacokinetic properties of insulin.Materials and MethodsThis was a three‐way, randomized, cross‐over, single‐center study involving 12 healthy Japanese adult males (age 27.4 ± 4.14 years; weight 64.2 ± 5.2 kg; body fat percentage 18.2 ± 1.5%). Participants received a subcutaneous (abdomen) dose of insulin lispro (1.5 U for participants weighing 55 to <65.0 kg; 2.0 U for participants weighing 65.0 to <80.0 kg) delivered using a 32‐G × 4 mm (32G × 4), 31‐G × 8 mm (31G × 8) or 32‐G × 6 mm (32G × 6) needle with a 3–7‐day washout between doses. Pharmacokinetic parameters of exogenous insulin were identified using non‐linear least squares, where the total insulin concentration was fit to the measured plasma insulin concentration using an overall combined model that accounted for C‐peptide/insulin secretion in addition to the injected dose.ResultsMaximum concentration and area under the curve for 0 to infinity min for insulin were bioequivalent for the 32G × 4 needle relative to the 32G × 6 and the 31G × 8 needles. The time to the maximum insulin concentration was bioequivalent for the 32G × 4 needle relative to the 32G × 6 needle, but not the 31G × 8 needle.ConclusionsThe use of 4‐mm needles is unlikely to change the pharmacokinetic properties of insulin when injected subcutaneously in adults. This trial was registered with UMIN‐CTR (no. UMIN000004469).
A high resolution view of the fly actin cytoskeleton lacking a functional WAVE complex
Authors: ZOBEL T. , BOGDAN S. 
Published: February 2013

SummaryThe development of multicellular organisms involves a series of morphogenetic processes coordinating a highly dynamic and organized interplay between cells and their environment. Thus, the generation of forces that drive cellular and intracellular movements is prerequisite to shape single cells into tissues and organs. The actin cytoskeleton represents a highly dynamic filamentous system providing cell structure and mechanical forces to drive membrane protrusion, cell migration and vesicle trafficking.Here, we apply the structured‐illumination microscopy (SIM) technique to analyse the actin cytoskeleton in fixed Drosophila Schneider (S2R+) cells, both in wild type and in cells depleted for WAVE, a major activator of Arp2/3 mediated actin polymerization. In addition, we demonstrate that live cell SIM imaging also allows the visualization of actin‐driven lamellipodial membrane dynamics at high spatial resolution in S2R+ cells. Three dimensional (3D) SIM images of up to 70 μm thick Drosophila wild‐type and abi‐mutant egg chambers further enables us to resolve changes of actin structures in a multicellular context with an impressive lateral and axial resolution, which is not possible with conventional confocal microscopy. Thus, the combination of superresolution 3D microscopy with Drosophila genetics and cell biology allows detailed insights into the structural and molecular requirements of different actin‐dependent processes.