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Hawking's black hole area theorem was proven using the null energy condition (NEC), a pointwise condition violated by quantum fields. The violation of the NEC is usually cited as the reason that black hole evaporation is allowed in the context of semiclassical gravity. Here we provide two generalizations of the classical black hole area theorem: first, a proof of the original theorem with an averaged condition, the weakest possible energy condition to prove the theorem using focusing of null geodesics. Second, a proof of an area-type result that allows for the shrinking of the black hole horizon but provides a bound on it. This bound can be translated to a bound on the black hole evaporation rate using a condition inspired from quantum energy inequalities. Finally, we show how our bound can be applied to two cases that violate classical energy conditions. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is the most common form of arthritis, that causes a significant decrease in the quality of life of the afflicted and constitutes a great burden for the socioeconomic system. Trace elements and heavy metals are implicated in the pathophysiology of OA, exacerbating inflammatory and oxidative stress responses. The aim of this cross-sectional study was to quantify metals in plasma samples of Greek OA patients and explore their link with disease related parameters, health status or quality of life, as well as epigenetic OA markers. This is the first study on plasma metal levels in Greek knee OA patients. To achieve precision in plasma metal and miRNA measurements, high-quality samples were selected from a subset of 34 participants (NCT04783792). Demographic, quality of life, clinical, biochemical, inflammation, oxidative stress, and anthropometric parameters, as well as microRNA levels were assessed. Significant correlations were found between circulating metals with OA related parameters or with measured microRNAs. Also, significant positive associations between plasma copper (Cu) levels and CRP (p = 0.033) or IL-6 (p = 0.001) occurred when adjusting for age, gender, BMI, physical activity level, smoking, disease severity, total arthroplasty, and dietary intake of the respective metal. Cu's role in OA is bidirectional, and this study confirms the findings that in OA, Cu is positively associated with inflammation. Such relationships between lifestyle, environment and OA enhance our understanding and encourage further study on metals related to OA inflammation. [ABSTRACT FROM AUTHOR]

In the present work, a thorough description of the creep response of polymers in both linear and nonlinear viscoelastic domains is presented. According to the proposed model, the polymeric structure is considered as an ensemble of meso-regions linked with each other while they can cooperatively relax and change their positions. Each meso-region has its own energy barrier that needs to be overcome for a transition to occur. It was found that the distribution function, followed by the energy barriers, attains a decisive role, given that it is associated with the distribution of retardation times and with their particular effect on the materials' time evolution. The crucial role of the imposed stress in a creep experiment by its influence on the retardation time spectrum of the polymeric structure was extensively analyzed. The proposed model has been successfully validated by a series of creep data in a variety of temperatures and stress levels for polymeric materials, studied experimentally elsewhere. Furthermore, the model's capability to predict the long-term creep response was analytically shown. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to investigate the association between muscle fiber composition, body composition, resting glycemic–lipidemic blood profiles, in apparently healthy, young, active females. Methods: Thirty-four young healthy female volunteers were allocated into two groups, depending on their Vastus Lateralis type IIx muscle fibers percent cross-sectional area (%CSA; H: high type IIx %CSA; L: low type IIx %CSA). Body composition was determined via dual-energy X-ray absorptiometry. Venous blood samples were collected for the determination of resting serum glucose, Insulin, Apo-A1, HOMA-IR, triglycerides (TG), total cholesterol (TC), High-density lipoprotein (HDL-C), and Low-density lipoprotein (LDL-C) concentrations. Nutritional intake was also evaluated. Results: Individuals of the H group have significantly higher body mass, body fat percentage-mass, and resting blood indices of glycemic and lipidemic profiles, compared to those of L group (p < 0.001). Increased type IIx and low type I, IIa muscle fibers %CSAs were linked with poorer body composition, glycemic and lipidemic blood profiles (r: − 0.722 to 0.740, p < 0.001). Linear regression analyses revealed that the impact of muscle fibers %CSA (B coefficients ranged between − 0.700 and 0.835) on the above parameters, was at least, of the same or even of greater magnitude as that of body composition and daily nutritional intake (B: − 0.700 to 0.666). Conclusion: Increased type IIx and low Type I, IIa %CSAs are associated with poorer body composition and glycemic–lipidemic profiles in young healthy females. The contribution of the muscle fiber %CSA on health status seems to be comparable to that of nutrition and body composition. [ABSTRACT FROM AUTHOR]

Metapopulation models have been a popular tool for the study of epidemic spread over a network of highly populated nodes (cities, provinces, countries) and have been extensively used in the context of the ongoing COVID-19 pandemic. In the present work, we revisit such a model, bearing a particular case example in mind, namely that of the region of Andalusia in Spain during the period of the summer-fall of 2020 (i.e., between the first and second pandemic waves). Our aim is to consider the possibility of incorporation of mobility across the province nodes focusing on mobile-phone time-dependent data, but also discussing the comparison for our case example with a gravity model, as well as with the dynamics in the absence of mobility. Our main finding is that mobility is key toward a quantitative understanding of the emergence of the second wave of the pandemic and that the most accurate way to capture it involves dynamic (rather than static) inclusion of time-dependent mobility matrices based on cell-phone data. Alternatives bearing no mobility are unable to capture the trends revealed by the data in the context of the metapopulation model considered herein. [ABSTRACT FROM AUTHOR]

Metabolomics experiments generate highly complex datasets, which are time and work-intensive, sometimes even error-prone if inspected manually. Therefore, new methods for automated, fast, reproducible, and accurate data processing and dereplication are required. Here, we present UmetaFlow, a computational workflow for untargeted metabolomics that combines algorithms for data pre-processing, spectral matching, molecular formula and structural predictions, and an integration to the GNPS workflows Feature-Based Molecular Networking and Ion Identity Molecular Networking for downstream analysis. UmetaFlow is implemented as a Snakemake workflow, making it easy to use, scalable, and reproducible. For more interactive computing, visualization, as well as development, the workflow is also implemented in Jupyter notebooks using the Python programming language and a set of Python bindings to the OpenMS algorithms (pyOpenMS). Finally, UmetaFlow is also offered as a web-based Graphical User Interface for parameter optimization and processing of smaller-sized datasets. UmetaFlow was validated with in-house LC–MS/MS datasets of actinomycetes producing known secondary metabolites, as well as commercial standards, and it detected all expected features and accurately annotated 76% of the molecular formulas and 65% of the structures. As a more generic validation, the publicly available MTBLS733 and MTBLS736 datasets were used for benchmarking, and UmetaFlow detected more than 90% of all ground truth features and performed exceptionally well in quantification and discriminating marker selection. We anticipate that UmetaFlow will provide a useful platform for the interpretation of large metabolomics datasets. [ABSTRACT FROM AUTHOR]

The classical singularity theorems of R. Penrose and S. Hawking from the 1960s show that, given a pointwise energy condition (and some causality as well as initial assumptions), spacetimes cannot be geodesically complete. Despite their great success, the theorems leave room for physically relevant improvements, especially regarding the classical energy conditions as essentially any quantum field theory necessarily violates them. While singularity theorems with weakened energy conditions exist for worldline integral bounds, so-called worldvolume bounds are in some cases more applicable than the worldline ones, such as the case of some massive free fields. In this paper, we study integral Ricci curvature bounds based on worldvolume quantum strong energy inequalities. Under the additional assumption of a—potentially very negative—global timelike Ricci curvature bound, a Hawking-type singularity theorem is proved. Finally, we apply the theorem to a cosmological scenario proving past geodesic incompleteness in cases where the worldline theorem was inconclusive. [ABSTRACT FROM AUTHOR]

A data-driven two-branch deep neural network (DNN), to be referred to as λ -DNN, used to predict scalar fields is presented. The network architecture consists of two separate branches (input layers) connected to the main one towards its output. In multi-disciplinary shape optimization problems, such as those this paper is dealing with, the input to the λ -DNN contains data relevant to the geometrical shape and the case itself. Herein, the λ -DNN is used in conjugate heat transfer (CHT) analysis and shape optimization problems, synergistically with codes simulating flows over the fluid domain and solving the heat conduction equations over the solid one. It is used to optimize a duct and an internally cooled turbine blade-airfoil surrounded by hot gas. The λ -DNNs, after being trained on fields computed using the CHT solver, are used as surrogates for either the heat conduction equation solver of the solid domain, replicating either one out of the two disciplines of the problem or the coupled CHT solver. [ABSTRACT FROM AUTHOR]

Streptomyces griseofuscus DSM 40191 is a fast growing Streptomyces strain that remains largely underexplored as a heterologous host. Here, we report the genome mining of S. griseofuscus, followed by the detailed exploration of its phenotype, including the production of native secondary metabolites and ability to utilise carbon, nitrogen, sulphur and phosphorus sources. Furthermore, several routes for genetic engineering of S. griseofuscus were explored, including use of GusA-based vectors, CRISPR-Cas9 and CRISPR-cBEST-mediated knockouts. Two out of the three native plasmids were cured using CRISPR-Cas9 technology, leading to the generation of strain S. griseofuscus DEL1. DEL1 was further modified by the full deletion of a pentamycin BGC and an unknown NRPS BGC, leading to the generation of strain DEL2, lacking approx. 500 kbp of the genome, which corresponds to a 5.19% genome reduction. DEL2 can be characterized by faster growth and inability to produce three main native metabolites: lankacidin, lankamycin, pentamycin and their derivatives. To test the ability of DEL2 to heterologously produce secondary metabolites, the actinorhodin BGC was used. We were able to observe a formation of a blue halo, indicating a potential production of actinorhodin by both DEL2 and a wild type. [ABSTRACT FROM AUTHOR]

This paper examines the effect of dispersant and anti-wear additives on fretting wear in lubricated bearing steel contacts. Reciprocating sliding ball-on-flat fretting tests with a stroke length of 50 μm have been carried out on steel-to-steel contacts in both dry and lubricated conditions. Wear and friction coefficient have been measured, and surface characterisation has been carried out using optical techniques to investigate fretting wear. The presence of base oil reduces fretting wear markedly compared to dry conditions, but fretting damage is still observed at low reciprocation frequencies. As frequency is increased, there is a transition from oxidative to adhesive/scuffing damage. The anti-wear additive ZDDP is effective in forming a tribofilm on the surfaces and reducing visible oxidation and wear. A succinimide dispersant also reduces the accumulation of solid debris but does not alleviate wear damage. The combination of both ZDDP anti-wear additive and dispersant in base oil appears to provide significant protection against fretting wear. [ABSTRACT FROM AUTHOR]

The present work comprises an upgraded version of a previous research of ours, referring to the evaluation of viscoelastic functions in a broad frequency and time scale. Our analysis is based on the assumption that the polymeric structure consists of an ensemble of meso-regions, with their own energy barrier, which follows a distribution. Through a cooperative process, the meso-regions are linked to each other, and perform rearrangements by changing their positions. The time-dependent behavior is controlled by the distribution energy barriers. In the present analysis, the distribution function will be evaluated by the experimental data of loss modulus. Hereafter, the viscoelastic functions can be evaluated, with further parameters. In addition, the temperature dependence of storage and loss modulus at a constant frequency can be described within the context of the proposed model. [ABSTRACT FROM AUTHOR]

In the present work, the non-isothermal creep response of a glassy polymer was experimentally studied and analyzed theoretically by a viscoelastic model, introduced in previous works. The main concept of this research is the prediction of the non-isothermal creep strain data on the basis of independent experimental results, namely dynamic mechanical analysis and stress–strain results at various temperatures. Two different approaches regarding the non-isothermal constitutive equation were studied, i.e., one established in the literature and the second one based on the assumption that the temperature dependence can be taken into account by utilizing the concept of the reduced time. A quite successful prediction of the non-isothermal creep strain has been achieved. [ABSTRACT FROM AUTHOR]

Leishmaniases are cutaneous, mucocutaneous, and visceral diseases affecting humans and domesticated animals mostly in the tropical and subtropical areas of the planet. Host genetics have been widely investigated for their role in developing various infectious diseases. The SLC11A1 gene has been reported to play a role in neutrophil function and is associated with susceptibility to infectious and inflammatory diseases such as tuberculosis or rheumatoid arthritis. In the present meta-analysis, we investigate the genetic association of SLC11A1 polymorphisms with susceptibility to leishmaniasis. Genotypes and other risk-related data were collected from 13 case-control and family-based studies (after literature search). Conventional random-effects meta-analysis was performed using STATA 13. To pool case-control and family-based data, the weighted Stouffer's method was also applied. Eight polymorphisms were investigated: rs2276631, rs3731865, rs3731864, rs17221959, rs201565523, rs2279015, rs17235409, and rs17235416. We found that rs17235409 (D543N) and rs17235416 (1729 + 55del4) are significantly associated with a risk for cutaneous leishmaniasis (CL), whereas rs17221959, rs2279015, and rs17235409 are associated with visceral leishmaniasis (VL). Our results suggest that polymorphisms in SLC11A1 affect susceptibility to CL and VL. These findings open new pathways in understanding macrophage response to Leishmania infection and the genetic factors predisposing to symptomatic CL or VL that can lead to the usage of predictive biomarkers in populations at risk. [ABSTRACT FROM AUTHOR]

In this work, the capacity of the generalized fractional Maxwell (GFMM) and Kelvin-Voigt (GFKM) models for the interconversion of dynamic to static (creep and relaxation) functions, with regard to appropriate experimental data of various polymeric structures, is examined. The analysis is executed within the frame of linear viscoelasticity. Furthermore, a comparative study with the results produced by the implementation of the fractional Zener model has been performed. A good approximation of the generated viscoelastic functions by GFKM and GFMM model was postulated. Concerning the fractional Zener model, it can be extracted that its effectiveness to the interconversion of the viscoelastic functions is dependent on the specific material's viscoelastic response, and the wideness of the time/frequency region examined. It was found that the incorporation of a correction factor in the calculation procedure of the creep compliance function can result in significantly better results, regardless of the model used. Graphical abstract [ABSTRACT FROM AUTHOR]

A variety of methods applicable to the interconversion of static (creep) and dynamic (relaxation) functions, with regard to appropriate experimental data of various polymers is investigated and compared. The effectiveness of the selected methods was verified by a series of creep experimental data of various polymeric structures. While most of the employed methods are well established in the literature, some further modifications have been introduced for an improvement of the conversion procedure. Furthermore, a new approach is also employed, which is based on the stretched-exponential function, usually applied to represent both relaxation and retardation functions. It is seen that the examined methods produce a similar result, concerning the creep compliance function, having as a beginning storage and loss modulus experimental data. The same observation applies to the retardation spectra, pointing the fact that discrete spectra deviates significantly from the continuous spectra. As a result, it is shown that the creep compliance function, or the relaxation modulus function, can be predicted using experimental dynamic data (relaxation or creep, respectively), as well as anyone of the examined interconversion methods, with an accuracy close to 5%. The use of approximate or exact relations in the whole procedure was proved not to have a significant effect on the final result (referring mostly to the retardation spectra). [ABSTRACT FROM AUTHOR]

An experimental study of a tensile loading-unloading procedure, as well as multi-cyclic response in a strain-controlled program of a Styrene-Butadiene (SBR) elastomer reinforced with four different weight fractions of carbon nanotubes (CNTs) has been performed. The Mullins effect features, namely hysteresis, damage and residual strain, exhibited by the SBR/nanocomposites were analyzed by a modified Gent-Zener rheological model, and a damage function. Especially for the multi-cyclic stress-strain curves, phenomenological equation of the model parameters evolution with strain were also introduced. The same loading procedure was applied in pre-stressed materials, revealing a different stress-strain response due to strain prehistory. The model has been proven to accurately capture the loading-unloading behavior, the residual strain, hysteresis loops as well as the multi-cyclic behavior of the SBR/CNT nanocomposites. [ABSTRACT FROM AUTHOR]

In the present work, the nonlinear viscoelastic/viscoplastic response of polymeric materials is described by introducing essential modifications on a model developed in previous works. A constitutive equation of viscoelasticity, based on the transient network theory, is introduced in a more generalized form, which takes into account volume changes during deformation. This time-dependent equation accounts for the nonlinearity and viscoplasticity at small elastic and finite plastic strain regime. The present description was proved to be more flexible, given that it contains a relaxation function that has been derived by considering instead of first order kinetics a fractional derivative that controls the rate of molecular chain detachment from their junctions. Therefore, the new equation has a more global character, appropriate for cases where heavy tails are expected. On the basis of the distributed nature of free volume, a new functional form of the rate of plastic deformation is developed, which is combined with a proper kinematic formulation and leads to the separation of the total strain into the elastic and plastic part. A three-dimensional constitutive equation is then derived for an isotropic, compressible medium. This analysis was proved to be capable of capturing the main aspects of inelastic response as well as the instability stage taking place at the tertiary creep, related to the creep failure. [ABSTRACT FROM AUTHOR]

To explore the potential role of computed tomographic cholangiography (CTC) in relation to magnetic resonance cholangiography (MRC) in cases in which knowledge of biliary kinetics and functional information are important for therapeutic decisions, 31 patients (14 men and 17 women) underwent MRC followed by CTC. We examined nine post-cholecystectomy cases with right upper quadrant abdominal pain, six cases with a previous biliary-enteric anastomosis and clinical evidence of cholangitis, eight biliary strictures with pain or symptoms of cholangitis, four cases with strong clinical evidence of sclerosing cholangitis, three cases with suspected post-laparoscopic cholecystectomy bile leakage, and one case with chronic pancreatitis and a common bile duct stent associated with cholangitis. In relation to MRC, CTC provided additional biliary functional information as follows: abnormal biliary drainage through the ampulla in 7/9 cholecystectomy cases, impaired drainage in 3/6 biliary-enteric anastomoses, and complete obstruction in 2/8 biliary strictures. CTC diagnosed early sclerosing cholangitis in 4/4 cases and confirmed suspected bile leakage in 1/3 post-laparoscopic cholecystectomy patients, and the patency of the biliary stent in the patient with chronic pancreatitis. Thus, CTC provides clinically important information about the function and kinetics of bile and complements findings obtained by MRC. [ABSTRACT FROM AUTHOR]

A new theoretical approach, analyzed in previous works, is employed for the description of the nonlinear viscoelastic/viscoplastic response of high density polyethylene under tensile cyclic loading, experimentally studied elsewhere. The proposed analysis, developed for a 3-D problem, is applied for a uniaxial cyclic deformation, in a strain-controlled program, where tensile loading up to maximum strain is followed by unloading to zero stress. This procedure is repeated for ten cycles. The same model is also applied for the simulation of a stress-controlled program, where cyclic loading takes place between a $\sigma_{\max}$ and $\sigma_{\min}$ engineering stress. The hysteresis loops of both programs could be adequately captured, with a number of model parameters, related to both, nonlinear viscoelasticity and viscoplasticity. The simulated ratcheting strain as well as its evolution with number of cycles is a very good approximation of the experimental one. A systematic study of the values of the adjustable parameters has been performed in order to monitor the effect of every specific internal variable, responsible for either the nonlinear viscoelastic or viscoplastic path in the simulations. It was found that in the proposed analysis a rather low number of model parameters are required, compared to the works existing in the literature. [ABSTRACT FROM AUTHOR]

Transit systems should provide attractive yet low cost services to passengers. However, reduction of operating costs can significantly affect performance of bus systems. Cutbacks in deadhead mileage and depot costs becomes attractive since it leads to reducing operating expenses without interfering with passenger services. We revisit previous work on the bus-to-depot allocation problem; we propose an improved model for assigning buses to depots and employ a novel hybrid genetic algorithm for solving the problem. The model and algorithm are applied to the Athens bus system. Results indicate gains in operating costs compared to the existing allocation and improved computational performance. [ABSTRACT FROM AUTHOR]

The nonlinear viscoelastic/viscoplastic response of polymeric materials is described by a new model based on previous works in terms of monotonic loading, stress-relaxation, and creep. In the proposed analysis, following a constitutive equation of viscoelasticity, based on the transient network theory, essential modifications are introduced, which account for the nonlinearity and viscoplasticity at small elastic and finite plastic strain regime. In addition, viscoplastic response is successfully analyzed by a proper kinematic formulation, which is combined with a functional form of the rate of plastic deformation. A three-dimensional constitutive equation is then derived for an isotropic incompressible medium. This analysis is capable of capturing the main aspects of inelastic response and the instability stage taking place at the tertiary creep, related to the creep failure. Model simulations described successfully the experimental data of polypropylene, which were performed elsewhere. [ABSTRACT FROM AUTHOR]

Cellular materials, based either on polymers or metals, exhibit similar compressive stress-strain response. In a previous work, this behavior has been described in terms of a statistical micromechanics model, which deals with the deformation of individual struts of the foam material, assuming that it is an isotropic one. However, due to the manufacturing process, cellular materials are substantially anisotropic, having different properties in the (foam) rise and transverse direction. In this study, the degree of anisotropy, has been taken into account by an orientation distribution function (ODF). The ODF has been treated as a probability density function and was used to calculate the rate of struts transition from elastic to buckling (yield) region. It has been found, that with this statistical model, the particular features of compressive response of polymeric and metallic foams in the rise and transverse direction, could be successfully described. [ABSTRACT FROM AUTHOR]

The patterns of MHC diversity were studied at UAA and DAB1 loci and the two domains involved in the recognition of antigenic peptides (α2 and β1, respectively) in eight Ladigesocypris ghigii populations inhabiting streams and a concrete reservoir, in order to understand the significance of these genes in bottlenecked populations of an endemic species and develop conservation rationale. In agreement with previous study employing RAPD and mtDNA markers (Mamuris et al., Freshw Biol 50:1441-1453, ), both loci exhibited a very low level of polymorphism with only two and four alleles detected for UAA and DAB1, respectively. The functional MHC diversity was even lower since UAA alleles were distinguished by a single synonymous substitution. The type of habitat did not affect the level of polymorphism. Our data suggest that DAB1 polymorphism might be the outcome of the positive selection, imposed by the temporal and spatial variation of pathogen load, and the genetic drift as a result of successive habitat shrinkage and deterioration by water abstraction year after year. The populations studied were significantly less diverged at MHC loci than expected based on nuclear and mtDNA markers, suggesting that common parasites might act as causative factors to homogenize selection. Sufficient epidemiological data are required for the interpretation of the results and decision-making on suitable conservation actions. [ABSTRACT FROM AUTHOR]

The outstanding improvement in the physical properties of cyanate esters (CEs) compared with those of competitor resins, such as epoxies, has attracted appreciable attention recently. Cyanate esters undergo thermal polycyclotrimerization to give polycyanurates (PCNs). However, like most thermo setting resins, the main draw back of CEs is brittleness. To over come this disadvan tage, CEs can be toughened by the introduction of polytetramethylene glycol (PTMG), a hydroxyl-terminated polyether. How ever, PTMG has a detrimental impact on Young’s modulus. To simultaneously enhance both the ductility and the stiffness of CE, we added PTMG and an organoclay (mont morillonite, MMT) to it. A series of PCN/PTMG/MMT nanocomposites with a constant PTMG weight ratio was pre pared, and the resulting nanophase morphology, i.e., the degree of filler dispersion and distribution in the composite and the thermomechanical properties, in terms of glass-transition behaviour, Young’s modulus, tensile strength, and elongation at break, were examined using the scanning elec tron micros copy (SEM), a dynamic mechanical analysis (DMA), and stress–strain measurements, re spectively. It was found that, at a content of MMT below 2 wt.%, MMT nanoparticles were distributed uniformly in the matrix, suggesting a lower degree of agglomeration for these materials. In the glassy state, the significant increase in the storage modulus revealed a great stiffening effect of MMT due to its high Young’s modulus. The modification with PTMG led to a 233% greater elongation at break compared with that of neat PCN. The nanocomposites exhibited an invariably higher Young’s modulus than PCN/PTMG for all the volume factors of organoclay examined, with the 2 wt.% material displaying the most pronounced in crease in the modulus, in agreement with micros copy results. [ABSTRACT FROM AUTHOR]

Time- and dose-dependent measurements of metabolites of galactose (with glucose as control) in various organs of rats are discussed . Not only the liver but especially the brain and to a lesser extent the muscles also have the capacity to take up and metabolize galactose. Primarily, the concentrations of UDP-galactose, a pivotal compound in the metabolism of galactose, and UDP-glucose are measured. An important feature lies in the demonstration that galactose and glucose are metabolized to amino acids and that the only increases observed in the brain appear in the concentrations of glutamate, glutamine, GABA measured after acute galactose loads. In addition the increase in the amino acid concentrations after galactose has been administered persists for longer periods of time than after glucose administration. This conversion of hexoses, especially galactose, to amino acids requires the consumption of ammonia equivalents in the brain; this finding might stimulate the use of galactose as a new means of removal of this neurotoxic compound from the brain in patients suffering from hepatic encephalopathy or Alzheimer’s disease. [ABSTRACT FROM AUTHOR]

A constitutive model of finite strain viscoelasticity, based on the multiplicative decomposition of the deformation gradient tensor into elastic and inelastic parts, is presented. The nonlinear response of rubbers, manifested by the rate effect, cycling loading and stress relaxation tests was captured through the introduction of two internal variables, namely the constitutive spin and the back stress tensor. These parameters, widely used in plasticity, are applied in this work to model the nonlinear viscoelastic behaviour of rubbers. The experimental results, obtained elsewhere, related with shear deformation in monotonic and cyclic loading, as well as stress-relaxation, were simulated with a good accuracy. [ABSTRACT FROM AUTHOR]

Sialic acid precursors are mediators of the sialic acid pathway. In this manuscript we present evidence that the application of sialic acid a precursor modulates gene expression and cell differentiation. The concept that sugars are involved in cellular transcription was first proposed by Jacob and Monod nearly 40 years ago studying the regulation of the lac-operon in prokaryotes. Surprisingly, these findings have never been transferred to eukaryotic systems. For our studies we have chosen PC12 cells. PC12-cells differentiate after application of NGF into a neuron-like phenotype. It is shown that treatment of PC12 cells with two different sialic acid precursors N-acetyl- or N-propanoylmannosamine, without application of NGF also induces neurite outgrowth. Moreover, the PC12 cells show the same morphology as the NGF-treated cells. Surprisingly, after application of both sialic acid precursors the phosphorylation and translocation of erk1/2 into the nucleus are activated, thus influencing the expression of genes involved in the differentiation of cells, such as the transcription factor c-Jun or TOAD-64/Ulip/CRMP (Turned ON After Division, 64 kd/ unc-33-like phosphoprotein/Collapsin Response Mediator Protein). These are the first experimental data showing that the sialic acid metabolism is closely associated with signal transduction and regulation of neuronal differentiation. [ABSTRACT FROM AUTHOR]

The structure-property relationships of thermoplastic polymer blends based on poly(ether-urethane) ionomer (PEUI) and ion-containing styrene-acrylic acid copolymer (S- co-AA(K)) have been investigated by using DMTA, DSC and TGA, as well as tensile tests. Convergence of the glass transition temperature ( T g) values of the PEUI and the S- co-AA(K) components in the blends studied, as compared to the individual polymers, was found and explained by improving compatibility of the components due to increasing effective density of physical networks formed by ion-dipole and ion-ion interactions of ionic groups of the components. Character of E'= f( T) and E''= f( T) dependencies confirms the increase of the effective density of physical networks in the compositions studied compared to individual PEUI and S- co-AA(K). Improvement of end-use properties, i.e. thermal stability and tensile properties has been found for the PEUI/S- co-AA(K) compositions with lower content of S- co-AA(K) (i.e. <10 mass%) and explained by formation of additional network of intermolecular ionic bonds between the functional groups of PEUI and S- co-AA(K). [ABSTRACT FROM AUTHOR]

Abstract An 8-year study was conducted on the island of Crete in order to identify airborne ascospores and to determine their seasonal pattern. A Burkard 7-day, volumetric spore-trap was continuously operated in the city of Irakleion??located in the center of the island from 1994 through 2001. Relatively high ascospore counts (20 48spores/m 3) were obtained from mid-spring through summer, while the rest of the year exhibited lower activity (816spores/m3). The predominant ascospores identified were those of Leptosphaeria and Chaetomium; their concentrations varied from 1 or 2 spores up to a few dozens of spores/m3. Other spores encountered sporadically were: Ascobolus, Endophragmiella, Didymella, Diatrypaceae, Leptosphaerulina, Massaria, Pleospora, Sporormiella, Xylaria. The mean daily concentration of all identified ascospores was 30/m3 for the entire study period, corresponding to 13.9% of the total fungal load. Ascospores have been recognized as important inhalant allergens and have been implicated as contributing to symptoms of both rhinitis and asthma. [ABSTRACT FROM AUTHOR]

In the present investigation, the methanol crossover rate through Nafion®-115 membrane at different temperatures and different concentrations had been investigated in a fuel cell test apparatus by using gas chromatography analysis. The single direct methanol fuel cell (DMFC) tests were carried out to investigate the effect of the concentration of methanol aqueous solutions and cell temperature on methanol crossover and consequently, on the open circuit voltage and the cell performance of DMFC. It can be found that the methanol crossover rate through Nafion® membrane increases as methanol concentration and temperature increase. It can also be found that methanol crossover presented a negative effect on the open circuit voltage and the single DMFC performance. Single DMFC test results showed that an improved cell performance was obtained as temperature increased although the methanol crossover rate increased with temperature increment. [ABSTRACT FROM AUTHOR]

Emerin is an inner nuclear membrane protein that is mutated or not expressed in patients with X-linked Emery-Dreifuss muscular dystrophy (X-EDMD/EMD). Cytoplasmic localization of emerin in cultured cells or tissues has been reported, although this remains a controversial issue. Tubular aggregates (TAs) are pathological structures seen in the sarcoplasm of human skeletal muscle fibers in various disorders. The TAs derive from the sarcoplasmic reticulum (SR) and represent, probably, an adaptive response of the SR to various insults to the muscle fibers. In the present study, we present immunohistochemical evidence of emerin expression in TAs. Muscle biopsies with tubular aggregates from four male, unrelated patients were studied. The percentage of muscle fibers containing TAs varied between 5 and 20%. Routine histochemistry revealed intense reaction of TAs with NADH-TR, AMPDA, and NSE, but not with COX, SDH, myosin ATPase (pH 9.4, 4.3, 4.6), PAS, and Oil red O staining. Immunohistochemical study revealed strong immunostaining of TAs with antibodies against emerin and7 SERCA2-ATPase. Immunostaining of TAs was also seen with antibodies against heat shock protein and dysferlin, but not with antibodies to lamin A, dystrophin, adhalin, β, γ, δ sarcoglycans, and merosin. These results suggest that emerin, an inner nuclear membrane protein, is present at the TAs. The interpretation and significance of this finding is discussed in relation to experimental data suggesting that normal emerin localization at the inner nuclear membrane depends on lamin A and mutations in the N-terminal domain of emerin cause mislocalization of the protein to the sarcoplasmic membranes. [ABSTRACT FROM AUTHOR]

Cancer cells have high levels of thioredoxin (Trx) and of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Cells from patients with the cancer-prone disease Fanconi anemia (FA) exhibit reduced Trx levels. We found the activity of GAPDH to correlate directly with the endogenous Trx content and mRNA transcripts for GAPDH and TRx reduced in FA cells. The treatment of cells with reduced human Trx stimulated the synthesis of GAPDH mRNA. Similarly, the transfection of cells with an expression plasmid for Trx increased GAPDH mRNA synthesis. Trx treatment of cells and subsequent analysis of the differential gene expression by human cDNA arrays containing about 50?000 different PCR products resulted in more than 300 up- or downregulated genes. Two representative genes, GAPDH and I?Ba/MAD-3, were further investigated to confirm their stimulation by Trx. Trx besides being the major carrier of redox potential of cells is also a regulator of gene expression on the transcriptional level. By regulation via Trx, cells are able to adapt to the prevailing redox conditions. These findings also enlighten the pathophysiology of FA in the respect that the characteristic diminution of Trx that results in the dysregulation of gene expression is a basis for the major symptoms of this disease.Oncogene (2004) 23, 2146-2152. doi:10.1038/sj.onc.1207334 Published online 19 January 2004 [ABSTRACT FROM AUTHOR]

In order to produce a hydrogen stream for fuel cell utilization, the study of the ethanol steam reforming process over an alumina supported palladium commercial catalyst was carried out. The effect of the reaction temperature, the H2O/C2H6O molar ratios and the contact time on catalytic activity and stability was studied. It was found that even at very low temperature values complete ethanol conversion was possible. Hydrogen selectivities up to 98% were obtained at temperature values close to 625 °C. It was also observed that for different reactant molar ratios carbon monoxide concentration exhibits a minimum at a temperature value close to 450 °C. Furthermore, carbon formation was found to be negligible even for H2O/C2H6O molar ratios equal to the stoichiometric one. [ABSTRACT FROM AUTHOR]

Presents a study which examined the effects of thioredoxin reduction in Fanconi anemia (FA) cells, which led to the analysis of the molecular phathophysiology of FA. Introduction to FA cells; Western blot analysis of the thioredoxin content in nuclei and cytoplasm of FA; Materials and methods.

A series of polyester-urethane block copolymers of various molecular weights was prepared via a two-step polymerization process. The prepolymer composition was kept constant in all the samples, while the NCO/OH ratio during the chain extension was varied from 0.9 to 1.2. Chemical and physical cross-linking effects were studied by means of F.T.I.R spectroscopy, swelling, and elastic behavior. Equilibrium stress-strain measurements and tensile-retraction tests were carried out to examine the elastomeric behavior of the materials tested. The extent of agreement between microscopic and macroscopic behavior was then evaluated. [ABSTRACT FROM AUTHOR]

Water absorption in particulate composites at ambient temperature influences their thermomechanical properties. Second Fick's law of diffusion was used in this paper to predict the diffusion coefficient of the composite materials tested. In all cases the matrix material was a diglycidyl ether of bisphenol-A polymer cured with 8 phr triethylene tetramine and filled with iron particles with an average diameter 150 μm at five distinct volume fractions v=0, 0.05, 0.10, 0.16 and 0.20. The modification of the modulus of elasticity, ultimate stress, breaking strain and breaking energy due to moisture absorption was examined. Moreover, differential scanning calorimetry was used to study the influence of the time exposure into water and the filler concentration of the particulates on their glass transition temperature. Finally, the void occupancy in the composite was evaluated from free volume considerations. [ABSTRACT FROM AUTHOR]

Viscoelastic parameters are strongly connected with the glass transition temperature and the degree of cross-linking of polymers. In this paper an attempt was undertaken to analyse the storage modulus in the rubbery plateau and the transition region of a series of plasticized epoxy polymers, in terms of their network structure, by means of dynamic measurements. A series of dynamic tests was carried out at frequencies between 0.1 and 100 Hz and temperatures from 50 °C to 140 °C. By applying the time-temperature superposition principle, composite curves for the storage modulus E′ ( ω) were derived over a wide frequency range. The crosslink density, or the molecular weight, between crosslinks could be changed by adding different amounts of plasticizer in the epoxy polymer, and it was calculated by applying the theory of rubber elasticity. The glass transition temperature T for each substance was found to be influenced by the amount of plasticizer and the molecular weight between crosslinks. This behaviour of the highly crosslinked epoxies was different from that of rubbers or analogous materials. Finally, an estimation of the free volume of the materials tested was attempted by using the WLF-equation. [ABSTRACT FROM AUTHOR]

Skin testing is the diagnostic cornerstone for allergies and is considered extremely safe. It is usually performed with the prick and the prick-to-prick method. The aim of this study is to report the first two pediatric cases of systemic allergic reactions during skin prick tests (SPT) with commercial food allergens. Both patients had a history of fish allergy. A 5-year-old girl, with a history of atopic dermatitis and asthma, reported an episode of urticaria and angioedema due to ingestion of fish, which had occurred 2 years before consultation. Ten minutes after having completed SPT to fish extracts, which had resulted positive, she suffered from generalized pruritus, nausea, stomach pain, and loss of consciousness. A 9-year-old boy, with a history of asthma and two episodes of acute urticaria and angioedema upon eating fish during infancy, reported a recent episode of oropharyngeal pruritus after tasting salmon. He was evaluated for fish allergy with SPT but developed conjunctivitis and acute urticaria during the first 10 min of the test. Anaphylaxis appears to be a rare side effect of skin testing in pediatric patients. Children with a history of asthma and atopic dermatitis are more likely to react. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "The JAK2 V617F mutation identifies a subgroup of MDS patients with isolated deletion 5q and a proliferative bone marrow" that appeared online in the April 13, 2006 issue of "Leukemia."

The skin reactivity to histamine was measured in 10 healthy and 10 atopic subjects after the ingestion of single doses of loratadine 10 mg, cetirizine diHCl 10 mg and placebo, in a double-blind cross-over randomized study. The anti-H effect of cetirizine diHCl proved to be significantly more rapid, more pronounced and longer lasting than that of loratadine. [ABSTRACT FROM AUTHOR]

Hawking’s singularity theorem concerns matter obeying the strong energy condition (SEC), which means that all observers experience a nonnegative effective energy density (EED), thereby guaranteeing the timelike convergence property. However, there are models that do not satisfy the SEC and therefore lie outside the scope of Hawking’s hypotheses, an important example being the massive Klein-Gordon field. Here we derive lower bounds on local averages of the EED for solutions to the Klein-Gordon equation, allowing nonzero mass and nonminimal coupling to the scalar curvature. The averages are taken along timelike geodesics or over spacetime volumes, and our bounds are valid for a range of coupling constants including both minimal and conformal coupling. Using methods developed by Fewster and Galloway, these lower bounds are applied to prove a Hawking-type singularity theorem for solutions to the Einstein-Klein-Gordon theory, asserting that solutions with sufficient initial contraction at a compact Cauchy surface will be future timelike geodesically incomplete. These results remain true in the presence of additional matter obeying both the strong and weak energy conditions. [ABSTRACT FROM AUTHOR]

The article discusses a survey of Greek intensive care physicians about their admission and end of life (EoL) attitudes under the current climate of severe economic austerity. Topics discussed include the attitudes of these physicians towards admission and EoL decisions, their practicing attitudes and the nature of difficulties they encounter.

Comments on the use of cetirizine in relieving rhinitis symptoms. Combination of cetirizine and pseudoephedrine; Adverse effects of cetrizine; Contraindication of the drugs to certain diseases.