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Dryland wetlands are resilient ecosystems that can adapt to extreme periodic drought–flood episodes. Climate change projections show increased drought severity in drylands that could compromise wetland resilience and reduce important habitat services. These recognized risks have been difficult to evaluate due to our limited capacity to establish comprehensive relationships between flood–drought episodes and vegetation responses at the relevant spatiotemporal scales. We address this issue by integrating detailed spatiotemporal flood–drought simulations with remotely sensed vegetation responses to water regimes in a dryland wetland known for its highly variable inundation. We show that a combination of drought tolerance and dormancy strategies allow wetland vegetation to recover after droughts and recolonize areas invaded by terrestrial species. However, climate change scenarios show widespread degradation during drought and limited recovery after floods. Importantly, the combination of degradation extent and increase in drought duration is critical for the habitat services wetland systems provide for waterbirds and fish. [ABSTRACT FROM AUTHOR]

Experimental studies on isolated cardiomyocytes from different animal species and human hearts have demonstrated that there are regional differences in the Ca2+ release, Ca2+ decay and sarcomere deformation. Local deformation heterogeneities can occur due to a combination of factors: regional/local differences in Ca2+ release and/or re-uptake, intra-cellular material properties, sarcomere proteins and distribution of the intracellular organelles. To investigate the possible causes of these heterogeneities, we developed a two-dimensional finite-element electromechanical model of a cardiomyocyte that takes into account the experimentally measured local deformation and cytosolic [Ca2+] to locally define the different variables of the constitutive equations describing the electro/mechanical behaviour of the cell. Then, the model was individualised to three different rat cardiac cells. The local [Ca2+] transients were used to define the [Ca2+]-dependent activation functions. The cell-specific local Young’s moduli were estimated by solving an inverse problem, minimizing the error between the measured and simulated local deformations along the longitudinal axis of the cell. We found that heterogeneities in the deformation during contraction were determined mainly by the local elasticity rather than the local amount of Ca2+, while in the relaxation phase deformation was mainly influenced by Ca2+ re-uptake. Our electromechanical model was able to successfully estimate the local elasticity along the longitudinal direction in three different cells. In conclusion, our proposed model seems to be a good approximation to assess the heterogeneous intracellular mechanical properties to help in the understanding of the underlying mechanisms of cardiomyocyte dysfunction. [ABSTRACT FROM AUTHOR]

The binary-driven hypernova (BdHN) model explains long gamma-ray bursts (GRBs) associated with supernovae (SNe) Ic through physical episodes that occur in a binary composed of a carbon-oxygen (CO) star and a neutron star (NS) companion in close orbit. The CO core collapse triggers the cataclysmic event, originating the SN and a newborn NS (hereafter ν NS) at its center. The ν NS and the NS accrete SN matter. BdHNe are classified based on the NS companion fate and the GRB energetics, mainly determined by the orbital period. In BdHNe I, the orbital period is of a few minutes, so the accretion causes the NS to collapse into a Kerr black hole (BH), explaining GRBs of energies > 10 52 erg. BdHN II, with longer periods of tens of minutes, yields a more massive but stable NS, accounting for GRBs of 10 50 – 10 52 erg. BdHNe III have still longer orbital periods (e.g., hours), so the NS companion has a negligible role, which explains GRBs with a lower energy release of < 10 50 erg. BdHN I and II might remain bound after the SN, so they could form NS-BH and binary NS (BNS), respectively. In BdHN III, the SN likely disrupts the system. We perform numerical simulations of BdHN II to compute the characteristic parameters of the BNS left by them, their mergers, and the associated short GRBs. We obtain the mass of the central remnant, whether it is likely to be a massive NS or a BH, the conditions for disk formation and its mass, and the event's energy release. The role of the NS nuclear equation of state is outlined. [ABSTRACT FROM AUTHOR]

Differences in mRNA expression levels have been observed in failing versus non-failing human hearts for several membrane channel proteins and accessory subunits. These differences may play a causal role in electrophysiological changes observed in human heart failure and atrial fibrillation, such as action potential (AP) prolongation, increased AP triangulation, decreased intracellular calcium transient (CaT) magnitude and decreased CaT triangulation. Our goal is to investigate whether the information contained in mRNA measurements can be used to predict cardiac electrophysiological remodeling in heart failure using computational modeling. Using mRNA data recently obtained from failing and non-failing human hearts, we construct failing and non-failing cell populations incorporating natural variability and up/down regulation of channel conductivities. Six biomarkers are calculated for each cell in each population, at cycle lengths between 1500 ms and 300 ms. Regression analysis is performed to determine which ion channels drive biomarker variability in failing versus non-failing cardiomyocytes. Our models suggest that reported mRNA expression changes are consistent with AP prolongation, increased AP triangulation, increased CaT duration, decreased CaT triangulation and amplitude, and increased delay between AP and CaT upstrokes in the failing population. Regression analysis reveals that changes in AP biomarkers are driven primarily by reduction in I, and changes in CaT biomarkers are driven predominantly by reduction in I and SERCA. In particular, the role of I is pacing rate dependent. Additionally, alternans developed at fast pacing rates for both failing and non-failing cardiomyocytes, but the underlying mechanisms are different in control and heart failure. [ABSTRACT FROM AUTHOR]

Aim: Activation of adrenergic receptors (AR) has been reported to enhance the growth and invasion of various malignancies. The effects of AR agonists on malignant hepatocyte proliferation and migration have yet to be determined. Methods: PLC/PRF/5 (PLC) and Huh-7 cells were exposed to a wide range of concentrations of the AR agonists noradrenaline (NA) and isoprenaline. Cell proliferation, migration, intracellular cyclic adenosine monophosphate (cAMP), protein kinase A (PKA) and C (PKC), matrix metalloproteinases (MMP)-2, -3, -7 and -9, and α1-, β1- and β2-AR expression were documented in both cell lines. Results: Cell proliferative activity was unaltered following exposure to physiological and stress-related concentrations of AR agonists but migration was accelerated, an effect that was inhibited by the nonselective β-AR antagonist labetalol. cAMP, PKA, PKC or MMP expression remained unchanged. Although α1- and β1-AR expressions were abundant, β2-AR expression was limited in both cell lines. Conclusion: Unlike other malignancies studied to date, in this study, the proliferative activity of malignant hepatocytes was not increased by exposure to AR agonists, a finding that could be explained by downregulation of β2-AR expression. The increase in malignant hepatocyte migration observed remains unexplained but does not appear to involve adenyl cyclase or MMP signaling pathways. [ABSTRACT FROM AUTHOR]

Abstract: A fully three dimensional finite-strain damage model for fibrous soft tissue is here presented. The model assumes uncoupled contributions for the matrix and collagen fibers, and uncoupled bulk and deviatoric response over any range of deformations. A simple isotropic damage mechanism within the framework of continuum damage mechanics has been used to describe the softening behavior under deformation for the matrix. On the other hand, statistical aspects related to the length distribution of the reinforcing fibers lead to a damage model for the reinforcing material. As a result, a general theoretical framework for constitutive modeling of biological soft tissue with continuum damage is obtained. The formulation has been implemented in a finite element framework and the capabilities of the model tested in three computer simulations of inhomogeneous boundary value problems. The results show the quadratic rate of convergence of the implementation and the ability to describe typical stress–strain behavior of fiber reinforced soft tissues. [Copyright &y& Elsevier]

Presents laboratory observations concerning unsteady bed shear stresses induced by navigation traffic. Space-time distribution of ensemble averaged wall shear stress; Analysis of the time evolution of the turbulence characteristics; Implications for sedimentary transport.

Atmospheric transmissivity (τ) is a critical factor in climatology, which affects surface energy balance, measured at a limited number of meteorological stations worldwide. With the limited availability of meteorological datasets in remote areas across different climatic regions, estimation of τ is becoming a challenging task for adequate hydrological, climatic, and crop modeling studies. The availability of solar radiation data is comparatively less accessible on a global scale than the temperature and precipitation datasets, which makes it necessary to develop methods to estimate τ. Most of the previous studies provided region specific datasets of τ, which usually provide local assessments. Hence, there is a necessity to give the empirical models for τ estimation on a global scale that can be easily assessed. This study presents the analysis of the τ relationship with varying geographic features and climatic factors like latitude, aridity index, cloud cover, precipitation, temperature, diurnal temperature range, and elevation. In addition to these factors, the applicability of these relationships was evaluated for different climate types. Thus, empirical models have been proposed for each climate type to estimate τ by using the most effective factors such as cloud cover and aridity index. The cloud cover is an important yet often overlooked factor that can be used to determine the global atmospheric transmissivity. The empirical relationship and statistical indicator provided the best performance in equatorial climates as the coefficient of determination (r2) was 0.88 relatively higher than the warm temperate (r2 = 0.74) and arid regions (r2 = 0.46). According to the results, it is believed that the analysis presented in this work is applicable for estimating the τ in different ecosystems across the globe. [ABSTRACT FROM AUTHOR]

• Insolation differences among the aspects amplify the variability in soil moisture. • Soil moisture and vegetation variability are sensitive to geomorphic factors. • Aspect-related vegetation differences are more pronounced in smaller contributing area. • Landscapes generated under low uplift rates display less spatial variability. Landscapes evolve through nonlinear interactions between soil, vegetation, and climate. In semi-arid ecosystems, soil moisture variability (SMV) and vegetation variability (VV) can be strongly related to landscape organisation induced by differences in insolation on opposing north-facing slopes (NFS) and south-facing slopes (SFS). Due to its complex interactions with various processes and factors, soil moisture and vegetation exhibit significant variability in both space and time. In this study, the Channel-Hillslope Integrated Landscape Development (CHILD) landscape evolution model (LEM), coupled to a dynamic vegetation model (BGM) and equipped with a spatially distributed solar radiation component is used. The model is used to investigate the implications of various soil, climatic, and geomorphic factors on SMV and VV over landscapes with different characteristics. The analysis of model results indicates that SMV and VV are more sensitive to changes in geomorphic (hillslope diffusion and uplift rate) and climate (solar radiation, precipitation) factors than to soil hydrologic factors (anisotropy, porosity, infiltration capacity, root depth, and pore size distribution) considered in this study. Spatial variability increases with decreases in hillslope diffusion, and with increases in uplift rates and latitude, while temporal variability has the same response to those factors, and also increases with precipitation. All of these factors contribute to larger difference in condition on NFS and SFS, which ultimately is reflected in SMV and VV. Slope-area, soil moisture-area, and vegetation-area relationships revealed that the difference in SMV and VV between NFS and SFS is more pronounced for smaller contributing areas, where NFS are steeper than SFS. They also show that the temporal variability of soil moisture and vegetation is less in SFS than in NFS. [ABSTRACT FROM AUTHOR]

The intensity of sperm competition is often measured wing the gonado-somatic index (testes/body weight). But sperm competition could be mediated more by size of the epididymis than by size of the testicles, and little information is available on the relationship between testicular and epididymal size. We found that both organs were positively correlated in size among male rhesus macaques. Body weight accounted far over 70% of variance in testicle size and valumetric estimates of testicle size accurately reflected testicle weight. We conclude that methods for ascertaining tide size are accurate, but the covariation in size between testicles epididymis will hamper understanding of the physiological mechanisms revolved in sperm competition in primates. [ABSTRACT FROM AUTHOR]

Catalytic iodine in the presence of water acts indirectly as a source of Brønsted acid and, concurrently, generates iodonium ion and hydrogen peroxide, which mediate the final oxidative aromatization step in the multicomponent cyclocondensation of an aromatic amine and two aliphatic aldehyde compounds. The oxidative cycle in this and related iodine‐catalyzed reactions is seldom discussed, generally unoptimized, and rarely investigated in detail. This work establishes that two independent catalytic cycles (H+ and I−/I+) drive such multicomponent cyclocondensation/ oxidation reactions, provided that the oxidant is generated in sufficient concentration to inhibit oxidation of the dihydroquinoline by the intermediate iminium cation. The complementary dual catalytic cycles, when optimized, act in concert to suppress side product formation, which simplifies isolation and purification of the self‐aggregating products, and increases the efficiency and scope of the Wang‐Kozlov multicomponent reaction. [ABSTRACT FROM AUTHOR]

The assessment of ecosystem quality and the maintenance of optimal ecosystem function require understanding vegetation area dynamics and their relationship with climate variables. This study aims to detect vegetation area changes downstream of the Hali dam, which was built in 2009, and to understand the influence of the dam as well as climatic variables on the region's vegetation areas from 2000 to 2020. The case study is located in an arid area with an average rainfall amount from 50 to 100 mm/year. An analysis of seasonal changes in vegetation areas was conducted using the Normalized Difference Vegetation Index (NDVI), and supervised image classification was used to evaluate changes in vegetation areas using Landsat imagery. Pearson correlation and multivariate linear regression were used to assess the response of local vegetation areas to both hydrologic changes due to dam construction and climate variability. The NDVI analysis revealed a considerable vegetation decline after the dam construction in the dry season. This is primarily associated with the impoundment of seasonal water by the dam and the increase in cropland areas due to dam irrigation. A significantly stronger correlation between vegetation changes and precipitation and temperature variations was observed before the dam construction. Furthermore, multivariant linear regression was used to evaluate the variations in equivalent water thickness (EWT), climate data, and NDVI before and after the dam construction. The results suggested that 85 percent of the variability in the mean NDVI was driven by climate variables and EWT before the dam construction. On the other hand, it was found that only 42 percent of the variations in the NDVI were driven by climate variables and EWT from 2010 to 2020 for both dry and wet seasons. [ABSTRACT FROM AUTHOR]

Our current understanding of semiarid ecosystems is that they tend to display higher vegetation greenness on polar‐facing slopes (PFS) than on equatorial‐facing slopes (EFS). However, recent studies have argued that higher vegetation greenness can occur on EFS during part of the year. To assess whether this seasonal reversal of aspect‐driven vegetation is a common occurrence, we conducted a global‐scale analysis of vegetation greenness on a monthly time scale over an 18‐year period (2000–2017). We examined the influence of climate seasonality on the normalized difference vegetation index (NDVI) values of PFS and EFS at 60 different catchments with aspect‐controlled vegetation located across all continents except Antarctica. Our results show that an overwhelming majority of sites (70%) display seasonal reversal, associated with transitions from water‐limited to energy‐limited conditions during wet winters. These findings highlight the need to consider seasonal variations of aspect‐driven vegetation patterns in ecohydrology, geomorphology, and Earth system models. Plain Language Summary: Sunny (equatorial‐facing) slopes receive more solar radiation than shady (polar‐facing) slopes. A common assumption in water‐limited semiarid ecosystems is that this difference in solar radiation results in shady slopes being greener than sunny slopes, because they lose less water to the atmosphere due to evapotranspiration. Some studies have suggested seasonal changes to this pattern, but the lack of a global‐scale analysis has prevented a clear understanding of the extent of this phenomenon and its causes. Here, we used an 18‐year record of remotely sensed monthly data to compare vegetation activity on opposing slopes in 60 semiarid catchments with different climates from all over the world. Our results show three different patterns: (1) always greener shady slopes; (2) greener shady slopes in summer but greener sunny slopes in winter; and (3) no discernible difference between slopes. Contrary to the common belief that shady slopes are always greener in semiarid landscapes, the majority of the studied sites show a seasonal reversal of this patterns in vegetation greenness. We attribute this contrasting behavior to the timing of precipitation and different growth responses of vegetation types on opposing slopes. At sites having wet winters, sunny slopes benefit more from solar radiation; hence, their vegetation grows more rapidly than that of shady slopes. These findings underline the importance of considering the seasonal variations of vegetation pattern on opposing slopes in ecohydrological, geomorphological, and Earth system models. Key Points: Hillslope aspect controls vegetation greenness in semiarid ecosystemsPolar‐facing slopes do not always have higher NDVI than equatorial‐facing slopesThe change in NDVI patterns is attributed to vegetation phenology and climate seasonality [ABSTRACT FROM AUTHOR]

Vegetation cover change is one of the key indicators used for monitoring environmental quality. It can accurately reflect changes in hydrology, climate, and human activities, especially in arid and semi-arid regions. The main goal of this paper is to review the remote sensing satellite sensors and the methods used for monitoring and mapping vegetation cover changes in arid and semi-arid. Arid and semi-arid lands are eco-sensitive environments with limited water resources and vegetation cover. Monitoring vegetation changes are especially important in arid and semi-arid regions due to the scarce and sensitive nature of the plant cover. Due to expected changes in vegetation cover, land productivity and biodiversity might be affected. Thus, early detection of vegetation cover changes and the assessment of their extent and severity at the local and regional scales become very important in preventing future biodiversity loss. Remote sensing data are useful for monitoring and mapping vegetation cover changes and have been used extensively for identifying, assessing, and mapping such changes in different regions. Remote sensing data, such as satellite images, can be obtained from satellite-based and aircraft-based sensors to monitor and detect vegetation cover changes. By combining remotely sensed images, e.g., from satellites and aircraft, with ground truth data, it is possible to improve the accuracy of monitoring and mapping techniques. Additionally, satellite imagery data combined with ancillary data such as slope, elevation, aspect, water bodies, and soil characteristics can detect vegetation cover changes at the species level. Using analytical methods, the data can then be used to derive vegetation indices for mapping and monitoring vegetation. [ABSTRACT FROM AUTHOR]

• We analyse climate variability/change effects on dryland wetland response to flows. • We use an emulator and an MC method to explore 4 K different flow conditions. • Wetland response for 30-year periods depends on average flow and flooding frequency. • Under current climate, wetland deterioration can occur 20% to 60% of the time. • Under a drier climate, deterioration can occur 85% to 95% of the time by 2100. During the Millennium Drought in southeast Australia (2001–2009), dryland wetlands experienced widespread ecological deterioration, which highlighted their vulnerability to natural climate variability and the potential effects of drying climate change. Here we use 30-year observed streamflow data (1991–2020) and numerical models to assess the impacts of climate variability and climate change on the Macquarie Marshes (the Marshes), a large floodplain wetland complex in the semi-arid region of New South Wales, Australia. A fast ecohydrologic emulator based on network linear programming with side constraints was developed to simulate the spatial and temporal responses of different wetland vegetation types to water regime. The emulator represents the wetland by a series of inter-connected level-pool reservoirs with the volume-discharge relationship obtained from a calibrated quasi-2d hydrodynamic model. The emulator reproduces daily flows and volume with good accuracy (Nash-Sutcliffe statistic ranging from 0.61 to 0.96) with 1/26,000 of the computational effort. We use the emulator to simulate the potential effects of climatic variability on vegetation by running the model over 30 years of observed data and 1000 statistically representative 30-year streamflow time series, which were generated using a stochastic model calibrated to the gauged flows. The collection of results for all 1000 contemporary simulations indicates the Marshes experience severe conditions 43% (± 18%) of the time in a 30-year period. We then ran an additional 6000 simulations to assess the combined impacts of climate variability and future climate change at the end of the century. For the driest future climates (-60% and -30% reduction in runoff), the Marshes remain in severe condition 89% (± 6%) and 63% (± 16%) of the time, respectively, while no major differences with respect to the contemporary conditions were found for the wetter future. Our results highlight the importance of quantifying the extent and uncertainty in the degradation of these ecosystems due to climate variability and change for informing management decisions. [Display omitted] [ABSTRACT FROM AUTHOR]

• Water-energy balance and plant phenology affect erosion in a landform evolution model. • Leaves, roots, litter, and soil carbon modulate erosion through different mechanisms. • Protection provided by Eucalyptus and rainfall in a tropical savanna are asynchronous. • Early rainy season erosion occurs at the savanna site due to lagged vegetation growth. • Modelling the dynamics of live biomass only, results in overprediction of erosion. Despite the scientific consensus that vegetation modifies erosion/deposition processes, traditional erosion and landform evolution models often include a simplified representation of vegetation dynamics, which does not consider the influence of the various biomass pools on erosion mechanisms. In this paper, we present a new modelling framework that couples dynamic modules of hydrology, vegetation, biomass pools and landform evolution/erosion processes. We analyse the effect of above and belowground biomass pools (leaves, roots, litter and soil carbon) changes in erosion rates by considering: (1) the effect of root biomass on soil erodibility, (2) the effect of leaf cover on soil diffusivity, (3) the effect of litter on flow resistance, and (4) the effect of soil carbon on soil water retention. We implement the model using daily data for an open-forest vegetation and ran different idealized experiments for a period of 100 years. The objectives of the experiments are to understand the combined effects of biomass pool dynamics and climatic seasonality on erosion patterns, and to compare results including the effects of various biomass pools on erosion versus those obtained using simplified formulations (i.e., bare soil, constant vegetation). Our results indicate that the erosion protection effects of the individual biomass pools are not simultaneous, with different biomass pools providing protection at different times of the year. We also find that simplified vegetation formulations (e.g. constant vegetation) can significantly under/overestimate erosion when compared with the fully dynamic biomass pools formulation. These findings highlight the importance of including a detailed representation of dynamic vegetation and biomass pools in models, to capture the feedbacks between erosion and vegetation processes and better understand and predict erosion/deposition processes. [ABSTRACT FROM AUTHOR]

Pancreas disease (PD) caused by salmonid alphavirus subtype 3 (SAV3) is a serious disease with large economic impact on farmed Norwegian Atlantic salmon production despite years of use of oil-adjuvanted vaccines against PD (OAVs). In this study, two commercially available PD vaccines, a DNA vaccine (DNAV) and an OAV, were compared in an experimental setting. At approximately 1040° days (dd) at 12 °C post immunization, the fish were challenged with SAV3 by cohabitation 9 days after transfer to sea water. Sampling was done prior to challenge and at 19, 54, and 83 days post-challenge (dpc). When compared to the OAV and control (Saline) groups, the DNAV group had significantly higher SAV3 neutralizing antibody titers after the immunization period, significantly lower SAV3 viremia levels at 19 dpc, significantly reduced transmission of SAV3 to naïve fish in the latter part of the viremic phase, significantly higher weight gain post-challenge, and significantly reduced prevalence and/or severity of SAV-induced morphologic changes in target organs. The DNAV group had also significantly higher post-challenge survival compared to the Saline group, but not to the OAV group. The data suggest that use of DNAV may reduce the economic impact of PD by protecting against destruction of the pancreas tissue and subsequent growth impairment which is the most common and costly clinical outcome of this disease. • Efficacy of a DNA vaccine (DNAV) against pancreas disease (PD) is shown • Efficacy of DNAV is compared to oil-adjuvanted whole virus PD vaccine (OAV) • DNAV provides stronger efficacy criteria than the OAV except mortality levels • Indirect efficacy based on neutralizing antibody levels in plasma and viremia • Efficacy as protection against growth loss and damage in target organs shown [ABSTRACT FROM AUTHOR]

Dryland wetlands are ecosystems of high ecological importance as they serve as habitat sanctuaries for aquatic and terrestrial biota in areas with very few resources; therefore, the study of such environments is of major importance for the conservation of biodiversity in arid and semi-arid areas. The vegetation organization in these ecosystems is driven by the water regime as the main driver, but local processes like seed banks and soil resources redistribution also play a crucial role in determining the spatial distribution of the vegetation. Assessment of vegetation dynamics and long-term resilience requires the use of realistic models that can integrate the water regime and that can continuously simulate vegetation extent and conditions under flood-drought cycles. Here we study the influence of the water regime as the main driver of the vegetation. We apply a vegetation-modelling framework to compare the performance of a simplified model at the cell scale and a model integrated at a patch scale. Our results show that aggregating the analysis of vegetation dynamics at the patch scale allows for the incorporation of the effects of both local drivers (acting within the patch) as well as the global drivers (acting over the patch as a whole). The water regime acts as a global driver for the vegetation and indirectly affects the local drivers. Our patch scale model successfully captures wetland vegetation dynamics using the water regime as the main driver for representing changes in the vegetation and assessment of the wetland resilience under flood-drought periods. Unlabelled Image • Vegetation resilience studies in dryland wetlands need realistic modelling tools. • Vegetation dynamics are mainly influenced by the water regime as a global driver. • We compare a simplified cellular automata model and one with a patch discretization. • Patch discretization model performs better simulating wetland vegetation extent. • Patch model indirectly includes local drivers that influence vegetation dynamics. [ABSTRACT FROM AUTHOR]

In this work, we present a novel method for the derivation of the unloaded geometry of an abdominal aortic aneurysm (AAA) from a pressurized geometiy in turn obtained by 3D reconstruction of computed tomography (CT) images. The approach was experimentally validated with an aneurysm phantom loaded with gauge pressures of 80, 120, and 140 mm Hg. The unloaded phantom geometries estimated from these pressurized states were compared to the actual unloaded phantom geometiy, resulting in mean nodal surface distances of up to 3.9% of the maximum aneuiysm diameter. An in-silico verification was also performed using a patient-specific AAA mesh, resulting in maximum nodal surface distances of 8 pm after running the algorithm for eight iterations. The methodology was then applied to 12 patient-specific AAA for which their corresponding unloaded geometries were generated in 5-8 iterations. The wall mechanics resulting from finite element analysis of the pressurized (CT image-based) and unloaded geometries were compared to quantify the relative importance of using an unloaded geometiy for AAA biomechanics. The pressurized AAA models underestimate peak wall stress (quantified by the first principal stress component) on average by 15% compared to the unloaded AAA models. The validation and application of the method, readily compatible with any finite element solver, underscores the importance of generating the unloaded AAA volume mesh prior to using wall stress as a biomechanical marker for rupture risk assessment. [ABSTRACT FROM AUTHOR]

Occupational accidents and injuries continue to be a critical concern for nurses, given the hazardous healthcare environment. This study advances the research on workplace safety by studying the process variables (i.e. job-related negative affect (JRNA) and job satisfaction) in explaining the relationship between safety climate and various safety criteria in nurses. Based on survey data from 326 nurses, our findings suggest that psychological safety climate is negatively related to JRNA, turnover intentions, safety workarounds, and workplace hazards. In addition, structural equation modelling indicated general support for a model in which psychological safety climate influences employee strain through job attitudes, including JRNA and job satisfaction. More specifically, job attitudes were found to mediate the relationship between psychological safety climate and turnover intentions, experience of hazards, and injuries. Safety workarounds did not significantly relate to injuries. The present study contributes to the ongoing improvement of interventions aimed at mitigating nurses’ injuries by integrating job attitudes into the safety climate–safety outcome framework. [ABSTRACT FROM PUBLISHER]

Abstract: Background: Despite being the stiffest airway of the bronchial tree, the trachea undergoes significant deformation due to intrathoracic pressure during breathing. The mechanical properties of the trachea affect the flow in the airway and may contribute to the biological function of the lung. Method: A Fung-type strain energy density function was used to investigate the nonlinear mechanical behavior of tracheal cartilage. A bending test on pig tracheal cartilage was performed and a mathematical model for analyzing the deformation of tracheal cartilage was developed. The constants included in the strain energy density function were determined by fitting the experimental data. Result: The experimental data show that tracheal cartilage is a nonlinear material displaying higher strength in compression than in tension. When the compression forces varied from −0.02 to −0.03N and from −0.03 to −0.04N, the deformation ratios were 11.03±2.18% and 7.27±1.59%, respectively. Both were much smaller than the deformation ratios (20.01±4.49%) under tension forces of 0.02 to 0.01N. The Fung-type strain energy density function can capture this nonlinear behavior very well, whilst the linear stress–strain relation cannot. It underestimates the stability of trachea by exaggerating the displacement in compression. This study may improve our understanding of the nonlinear behavior of tracheal cartilage and it may be useful for the future study on tracheal collapse behavior under physiological and pathological conditions. [Copyright &y& Elsevier]

The article discusses a study which examines the extracellular and intracellular zidovudine (ZDV) and lamivudine (3TC) levels in blood and semen of men with HIV-1 infection. The study found that ZDV and 3TC seminal plasma exposure are 2- to 6-fold higher than blood plasma exposure. The study also found that pharmacokinetic variability makes individual seminal plasma/blood plasma ratios a suboptimal surrogate for genital tract exposure.

Infectious bursal disease virus (IBDV) capsids are formed by a single protein layer containing three polypeptides, pVP2, VP2, and VP3. Here, we show that the VP3 protein synthesized in insect cells, either after expression of the complete polyprotein or from a VP3 gene construct, is proteolytically degraded, leading to the accumulation of product lacking the 13 C-terminal residues. This finding led to identification of the VP3 oligomerization domain within a 24-amino-acid stretch near the C-terminal end of the polypeptide, partially overlapping the VP1 binding domain. Inactivation of the VP3 oligomerization domain, by either proteolysis or deletion of the polyprotein gene, abolishes virus-like particle formation. Formation of VP3-VP1 complexes in cells infected with a dual recombinant baculovirus simultaneously expressing the polyprotein and VP1 prevented VP3 proteolysis and led to efficient virus-like particle formation in insect cells. [ABSTRACT FROM AUTHOR]

Systemic and intracellular pharmacokinetics of zidovudine were determined for 28 human immunodeficiency virus type 1-infected pregnant women and their newborn infants. Plasma zidovudine and intracellular zidovudine monophosphate and triphosphate concentrations were determined in serial maternal samples and cord blood at delivery. Higher levels of cord blood zidovudine were associated with lower maternal zidovudine clearance and longer infusion times. Median levels of zidovudine monophosphate and triphosphate in maternal (1556 and 67 fmol/10[sup6] cells) and cord (1464 and 70 fmol/10[sup6] cells) blood were similar but highly variable. Intersubject pharmacokinetic variability for zidovudine is substantial, but intravenous therapy provides plasma concentrations and intracellular zidovudine triphosphate levels consistent with high antiviral activity. The substantial amount of intracellular zidovudine triphosphate in cord blood provides an explanation for the clinical success of zidovudine in reducing vertical transmission. Studies of simpler oral regimens of zidovudine can now be evaluated regarding the ability to achieve these pharmacologic end points associated with highly effective parenteral therapy. [ABSTRACT FROM AUTHOR]

Contrasts in insolation lead to the development of aspect-controlled ecosystems characterized by heterogeneity in vegetation type and density in semi-arid ecosystems. Vegetation dynamics are strongly influenced by the availability of soil moisture on opposing hillslopes in semi-arid landscapes. Aspect controls on vegetation type and density have long fascinated ecologists as well as geomorphologists, and they mostly claim that polar-facing slopes (PFS) have denser vegetation than equator-facing slopes (EFS). While this observation characterizes the mean state of ecosystems, here we examine the seasonality of aspect-controlled ecosystems to gain insights about the vegetation protection for erosion. Here, we extracted NDVI values derived from Landsat 5, 7, and 8 (obtained from Google Earth Engine) for a 17 year period for 80 different catchments across the world having a size from 5 to 200 square km, where aspect-controlled vegetation has been reported. For each of the 80 catchments, we calculated the mean monthly NDVI values for PFS and EFS. Patterns of monthly mean NDVI reveal two broad categories for aspect dependent ecosystems; 1) higher NDVI on PFS all-year-round; (2) higher NDVI on EFS during the winter season. Higher NDVI on PFS is attributed to less insolation preserving valuable moisture in this semi-arid landscapes. One explanation for the observed winter reversal in NDVI may be attributed to preferential snow cover on PFS. The spatial NDVI analysis at such sites shows the seasonal reversal of NDVI on opposing hillslopes. Using the NDSI (normalized difference snow index) datasets for the last 17 years and air temperature records, we show that snow cover is absent from some sites still displaying a winter reversal in NDVI contrasts. Another explanation for this NDVI reversal in snow-free sites is favourable winter growing conditions for vegetation when the wet season in Mediterranean climate meets with relatively higher insolation on EFS. We suggest the winter reversal in NDVI in those sites can be ascribed to vegetation functionality and relatively higher insolation on EFS in winter with available soil moisture. These findings show that in aspect-controlled ecosystems, seasonal reversals in erosion protection provided by vegetation can alter erosion mechanisms on PFS and EFS. [ABSTRACT FROM AUTHOR]