1,212 research outputs found
Vesicle adhesion and fusion studied by small-angle x-ray scattering.
We have studied the adhesion state (also denoted by docking state) of lipid vesicles as induced by the divalent ions Ca2+ or Mg2+ at well-controlled ion concentration, lipid composition, and charge density. The bilayer structure and the interbilayer distance in the docking state were analyzed by small-angle x-ray scattering. A strong adhesion state was observed for DOPC:DOPS vesicles, indicating like-charge attraction resulting from ion correlations. The observed interbilayer separations of ∼1.6 nm agree quantitatively with the predictions of electrostatics in the strong coupling regime. Although this phenomenon was observed when mixing anionic and zwitterionic (or neutral) lipids, pure anionic membranes (DOPS) with highest charge density σ resulted in a direct phase transition to a multilamellar state, which must be accompanied by rupture and fusion of vesicles. To extend the structural assay toward protein-controlled docking and fusion, we have characterized reconstituted N-ethylmaleimide-sensitive factor attachment protein receptors in controlled proteoliposome suspensions by small-angle x-ray scattering
Quantization with maximally degenerate Poisson brackets: The harmonic oscillator!
Nambu's construction of multi-linear brackets for super-integrable systems
can be thought of as degenerate Poisson brackets with a maximal set of Casimirs
in their kernel. By introducing privileged coordinates in phase space these
degenerate Poisson brackets are brought to the form of Heisenberg's equations.
We propose a definition for constructing quantum operators for classical
functions which enables us to turn the maximally degenerate Poisson brackets
into operators. They pose a set of eigenvalue problems for a new state vector.
The requirement of the single valuedness of this eigenfunction leads to
quantization. The example of the harmonic oscillator is used to illustrate this
general procedure for quantizing a class of maximally super-integrable systems
The comparision of glybenclamide and metformin-loaded bacterial cellulose/gelatin nanofibres produced by a portable electrohydrodynamic gun for diabetic wound healing
Wound dressings made from natural polymers are an important aspect of biomaterials. Protein-based materials are less likely to instigate an immunogenic response and have the capacity to degrade in vivo, also without triggering an inflammatory response. Therefore, gelatin (GEL) was chosen and combined with bacterial cellulose (BC) to produce nanofibres and the potential of an all-natural polymer construct was determined. GEL and BC were successfully electrospun with metformin (Met) and glybenclamide (Gb) using a portable, point of need electrospinning set up. The virgin fibre group exhibited a significant effect on the proliferation of L929 (mouse fibroblast) cells but all fibre samples can safely be applied on wound site without risk of cytotoxicity. According to the results obtained by animal tests, the GEL-BC-Gb group showed better recovery than the GEL-BC-Met group. Diabetic wounds treated with GEL-BC-Met were characterized by moderate re-epithelialization and partially organized granulation tissue. Moderate to complete re-epithelialization and well-formed granulation tissue were observed in diabetic wounds treated with GEL-BC-Gb. The histologic scores obtained on day 14 confirmed that the GEL-BC-Gb group played a stronger wound-healing role compared to the GEL-BC-Met group. The highest decrease of TNF-α level was observed in the GEL-BC-Gb group at the end of the experiment but there is no significant difference between drug-loaded fibre groups. Therefore, topical administration of Met and Gb in a sustained release form has a high potential for diabetic wound healing with high bioavailability and fewer systemic side effects but Gb showed better improvement according to the results of the animal tests
A meta-analysis of training effects on English phonological awareness and reading in native Chinese speakers
Enhancing English phonological awareness is critical in promoting native English speakers’ reading development. However, less attention has been paid to the role of phonological awareness development for English language learners in a logographic context. This meta-analysis aims to evaluate the effectiveness of training native Chinese speakers’ English phonological awareness and reading across age groups. Thirty-three articles, including 37 independent samples, were identified as training studies that reported English phonological awareness as an outcome measure, and 16 articles, including 17 independent samples, featured training studies that reported reading as an outcome measure. Results based on a random-effect model revealed the effect sizes for overall English phonological awareness (including English syllable awareness, phoneme awareness, and rhyme awareness) and overall reading (including word reading and pseudoword reading) were g = 0.651 (n = 3137) and g = 0.498 (n = 1506), respectively. Specifically, instructional training exerted a small impact on word reading (g = 0.297), moderate effects on syllable awareness (g = 0.468) and pseudoword reading (g = 0.586), a medium to large effect on phoneme awareness (g = 0.736), and a large impact on rhyme awareness (g = 0.948). The moderator analyses yielded several significant findings. Regarding the English phonological awareness outcome, programs integrating lexical semantic knowledge exhibited the largest trend in enhancing native Chinese speakers’ skills. Among all age groups, upper elementary students benefited most from instructional training. Furthermore, more intensive training had a greater impact than less intensive training. In terms of the reading outcome, similar to English phonological awareness findings, upper elementary students realized the greatest improvements. Additionally, unpublished articles indicated a larger training effect on reading than published ones. These findings provide practitioners with guidelines for delivering effective instruction to promote phonological awareness and reading ability for English language learners in a logographic language context
COMPARATIVE ANALYSIS OF THE MAJOR DENTAL PATHOLOGIES PREVALENCE AMONG CHILDREN OF TRANSCARPATHIAN REGION ACCORDING TO THE DATA OF THE STUDIED CLINICAL SAMPLE AND PRELIMINARY PERFORMED DENTAL RESEARCH
Taking into account the presence of pre-conducted epidemiological studies on the territory of Transcarpathian region devoted to the question of major dental pathologies prevalence among children, it is advisable to systematize and compare their results with each other, as well as with data obtained during a specifically formed study sample of children and adolescents.
The aim of the study – to provide a comparative analysis of the major dental pathologies prevalence among children of Transcarpathian region according to the data of the studied clinical sample and preliminary performed dental populational studies.
Materials and Methods. For the realization of the formulated research objective, a retrospective analysis of medical records and a dental examination of 411 children and adolescents were provided on the base of University Dental Clinic (Uzhhorod National University). Categorization of patients was provided due to their age-related passport indices with the formation and distribution of subgroups with a 1-year difference. Google Scholar search form (http://scholar.google.com) was used with its advanced features for the systematization of previously conducted studies aimed at registration of major dental pathologies among children of Transcarpathian region. The following sets of words «dental disease», «children» and «Transcarpathian region» were used as header operators in various combinations, each resulting for the set of academic papers on relevant topics, that were subsequently subject to content analysis.
Results and Discussion. The average caries prevalence among studied clinical sample of 411 pediatric patients in the age range of 6.0–15.9 years was 73.2 % (included in the range of results provided by pre-conducted epidemiological studies), the average teeth crowding prevalence in the age range of 6.0–15.9 years was 18.82 % (below the range of results provided by pre-conducted epidemiological studies), the average dystopia prevalence in the age range of 6.0–15.9 years was 14.69 % (included in the range of results provided by pre-conducted epidemiological studies), the average primary edentulism prevalence in the age range of 6.0–15.9 years was 2.31 % (included in the range of results provided by pre-conducted epidemiological studies), the average super numerary teeth prevalence in the age range of 6.0–15.9 years was 0.82 % (included in the range of results provided by pre-conducted epidemiological studies), the average delay in teeth eruption prevalence in the age range of 6–15.9 years was noted in 8.65 % of clinical cases (included in the range of results provided by pre-conducted epidemiological studies).
Conclusions. Thus, in the course of this phase of study, which was aimed to provide comparative analysis of the major dental pathologies prevalence among children and adolescents, and was conducted through a retrospective review of medical documentation and examination of 411 dental pediatric patients, it was found that the established prevalence of different pathologies does not statistically differ from the indicators, which were given in previous epidemiological studies. The small absolute difference of the indicators can be justified by the discrepancy in the size of samples being studied, the analysis of the certain pathologies prevalence outside Transcarpathian regions, the discrepancy in age categorization given in various studies, the researches of the stomatological status of the children's population living in different regions of Transcarpathia
What has finite element analysis taught us about diabetic foot disease and its management?:a systematic review
Over the past two decades finite element (FE) analysis has become a popular tool for researchers seeking to simulate the biomechanics of the healthy and diabetic foot. The primary aims of these simulations have been to improve our understanding of the foot's complicated mechanical loading in health and disease and to inform interventions designed to prevent plantar ulceration, a major complication of diabetes. This article provides a systematic review and summary of the findings from FE analysis-based computational simulations of the diabetic foot.A systematic literature search was carried out and 31 relevant articles were identified covering three primary themes: methodological aspects relevant to modelling the diabetic foot; investigations of the pathomechanics of the diabetic foot; and simulation-based design of interventions to reduce ulceration risk.Methodological studies illustrated appropriate use of FE analysis for simulation of foot mechanics, incorporating nonlinear tissue mechanics, contact and rigid body movements. FE studies of pathomechanics have provided estimates of internal soft tissue stresses, and suggest that such stresses may often be considerably larger than those measured at the plantar surface and are proportionally greater in the diabetic foot compared to controls. FE analysis allowed evaluation of insole performance and development of new insole designs, footwear and corrective surgery to effectively provide intervention strategies. The technique also presents the opportunity to simulate the effect of changes associated with the diabetic foot on non-mechanical factors such as blood supply to local tissues.While significant advancement in diabetic foot research has been made possible by the use of FE analysis, translational utility of this powerful tool for routine clinical care at the patient level requires adoption of cost-effective (both in terms of labour and computation) and reliable approaches with clear clinical validity for decision making
Electrically-driven phase transition in magnetite nanostructures
Magnetite (FeO), an archetypal transition metal oxide, has been
used for thousands of years, from lodestones in primitive compasses[1] to a
candidate material for magnetoelectronic devices.[2] In 1939 Verwey[3] found
that bulk magnetite undergoes a transition at T 120 K from a
high temperature "bad metal" conducting phase to a low-temperature insulating
phase. He suggested[4] that high temperature conduction is via the fluctuating
and correlated valences of the octahedral iron atoms, and that the transition
is the onset of charge ordering upon cooling. The Verwey transition mechanism
and the question of charge ordering remain highly controversial.[5-11] Here we
show that magnetite nanocrystals and single-crystal thin films exhibit an
electrically driven phase transition below the Verwey temperature. The
signature of this transition is the onset of sharp conductance switching in
high electric fields, hysteretic in voltage. We demonstrate that this
transition is not due to local heating, but instead is due to the breakdown of
the correlated insulating state when driven out of equilibrium by electrical
bias. We anticipate that further studies of this newly observed transition and
its low-temperature conducting phase will shed light on how charge ordering and
vibrational degrees of freedom determine the ground state of this important
compound.Comment: 17 pages, 4 figure
Editorial of Special Issue of National Identities: Alevism as an ethno-religious identity: Contested boundaries
No abstract for editorial but this is the opening paragraph:
This special issue on Alevism and trans/national Alevi identity critically engages with the relationship between religion, ethnicity and national identity. The core issues are as follows:
• how ethnicity and religion are conceptualised for a relatively invisible ethnic group in different national contexts;
• how religion and ethnicity intersect when Alevism is both a faith and an ethnic identity, especially when conceptions of that identity are contested;
• how identity is shaped through state policies within different national policy contexts and how etic definitions of minority communities are constructed by the state or other agencies with the power to impose them on the community in contrast to the emic or self-definitions of Aleviness from within the Alevi community;
• how despite the fragmented, heterogeneous nature of Alevi communities, there is also a sense of a single, transnational imaginary community, at least for the purposes of political assimilation/integration and activism;
• how education and other arenas of political, religious and cultural engagement at local, national and transnational levels create the possibilities, both positively and negatively, for future action/policy to situate minority ethnic communities
Immune monitoring of mycophenolate mofetil activity in healthy volunteers using ex vivo T cell function assays
Mycophenolate mofetil (MMF) is part of the standard immunosuppressive treatment after transplantation and usually given as "one-dose-fits-all" together with a calcineurin inhibitor (CNI). Although drug concentrations are frequently monitored, there is still a group of patients who experience side effects related to excessive or insufficient immune suppression. We therefore aimed to identify biomarkers that reflect the overall immune status of the patient and might support individualized dosing. We previously studied immune biomarkers for CNIs and aimed to investigate whether these are also suitable to monitor MMF activity. Healthy volunteers received a single dose of MMF or placebo, after which IMPDH enzymatic activity, T cell proliferation, and cytokine production were measured and compared to MPA (MMF's active metabolite) concentration in three different matrices (plasma, peripheral blood mononuclear cells, and T cells). MPA concentrations in T cells exceeded those in PBMCs, but all intracellular concentrations correlated strongly with plasma concentrations. At clinically relevant MPA concentrations, IL-2 and IFN-& gamma; production was mildly suppressed, while MPA T cell proliferation was strongly inhibited. Based on these data, it is expected that monitoring of T cell proliferation in MMF-treated transplantation patients may be a valid strategy to avoid excessive immune suppression.Personalised Therapeutic
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