An augmented Lagrangian finite element formulation for 3D contact of biphasic tissues

Biphasic contact analysis is essential to obtain a complete understanding of soft tissue biomechanics, and the importance of physiological structure on the joint biomechanics has long been recognised; however, up to date, there are no successful developments of biphasic finite element contact analysis for three-dimensional (3D) geometries of physiological joints. The aim of this study was to develop a finite element formulation for biphasic contact of 3D physiological joints. The augmented Lagrangian method was used to enforce the continuity of contact traction and fluid pressure across the contact interface. The biphasic contact method was implemented in the commercial software COMSOL Multiphysics 4.2^® (COMSOL, Inc., Burlington, MA). The accuracy of the implementation was verified using 3D biphasic contact problems, including indentation with a flat-ended indenter and contact of glenohumeral cartilage layers. The ability of the method to model multibody biphasic contact of physiological joints was proved by a 3D knee model. The 3D biphasic finite element contact method developed in this study can be used to study the biphasic behaviours of the physiological joints.     

The effects of foot reflexology on pain and physiological indicators in children with leukemia under chemotherapy: a clinical trial study

BackgroundFoot reflexology is a popular complementary medicine method; however, previous studies have shown conflicting results. This study aimed to investigate the impact of foot reflexology on pain and physiological responses caused by intrathecal injection of chemotherapy drugs in children with leukemia.Materials and methodsThis clinical trial included 80 children with leukemia. The participants received 20 min foot reflexology (10 min each foot). The primary measured outcomes included pain and physiological indicators (blood pressure and heart rate).ResultsThe results showed that foot reflexology had a significant effect on reducing pain (p = 0.002) and improving physiological indicators [blood pressure (p = 0.002) and heart rate (p = 0.003)].ConclusionBased on the results of the present study, which shows the positive effect of foot reflexology on the improvement of pain and physiological indicators, foot reflexology can be used as a complementary treatment along with conventional therapies.     

Flow cytometry to assess biochemical pathways in heat-stressed Cronobacter spp. (formerly Enterobacter sakazakii)

Aims: Using a flow cytometry (FC)‐based approach in combination with four selected fluorescent probes, the biochemical pathway activated following the adaptation of Cronobacter spp. to lethal heat stress was investigated. This approach assessed the physiological changes induced in four strains of Cronobacter spp. Methods and Results: Using the commercially available live/dead viability assessment fluorescence probes, live, injured or dead bacterial cells were studied. Cellular respiration and membrane potential were evaluated using the dye‐labelled probe 3,3′‐dihexylocarbocyanine iodide, metabolic activity was evaluated using a fluorescein diacetate (FDA) probe, intracellular pH changes were measured using a carboxy‐fluorescein diacetate succinimidyl ester probe, and reactive oxygen species were measured using a hydroethidine fluorescent probe. Adaptation to lethal heat stress induced physiological changes that potentially improve the survival of Cronobacter spp. Conclusions: These data showed that in situ assessment of physiological behaviour of lethally stressed cells using multiparameter FC is a useful, rapid and sensitive tool to study and assess the viability and physiological state of Cronobacter cells. Significance and Impact of the Study:  This study shows that FC is a valuable tool in the study of physiological aspects of increased survival because of sublethal adaptation to heat.     

Field Studies of Photosynthesis as Affected by Water Stress, Temperature, and Light in Birch

This study continues the investigations previously conducted as laboratory experiments. The results from the present study confirm our earlier observations made on alder seedlings concerning the effect of water stress, temperature and light on the net uptake of CO₂. A variable that we could call the physiological water stress is proposed as a measure of the intrinsic factor of photosynthesis during and after drought. A physiological water stress builds up and discharges slowly and interacts strongly with temperature. Our model for the effects of physiological water stress, temperature, and light intensity explains satisfactorily the net uptake of CO₂ in birch in the field. Thus, our earlier results concerning the effects of physiological water stress on photosynthesis are not artifacts generated by the unnatural laboratory environment.     

Systematic comparisons of artificial urine formulas for in vitro cellular study

Artificial urine (AU) is widely used for in vitro cellular study to simulate normal physiological environment of the kidney and urinary tract. However, some compositions of many of previously established AU formulas are out of their physiological ranges in normal human urine. Therefore, we established a new AU formula, named “AU-Siriraj,” and then performed systematic comparisons of AU-Siriraj with other six previously established AU formulas, ultrafiltrated (UF) urine, and blank-control to determine their compatibility with MDCK cells. The data indicate that AU-Siriraj is the best, and AU-3 is the second best, AU formula for in vitro cellular study.     

Improvement of transglutaminase production by extending differentiation phase of Streptomyces hygroscopicus: mechanism and application

Streptomyces transglutaminase (TGase) is an important industrial enzyme that catalyzes cross-linking of proteins. It is secreted as a zymogene and then is activated by proteases under physiological conditions. Although the activation process of TGase has been well investigated, the physiological function of TGase in Streptomyces has not been revealed. In this study, physiological function of TGase from Streptomyces hygroscopicus was found to be involved in differentiation by construction of a TGase gene interruption mutation strain (Δtg). The mutant Δtg showed an absence of differentiation compared with the parent strain. Furthermore, the production of TGase was found to be increased with the extending growth arrest phase of mycelium in submerged cultures. Thus, to enhance yield of TGase, the mycelium differentiation of Streptomyces was regulated via low temperature stress in a 3-L stirred-tank fermenter. The production of TGase increased by 39 % through extending the growth arrest phase for 4 h. This study found that TGase is involved in Streptomyces differentiation and proposed an approach to improve TGase production by regulation of mycelium differentiation in submerged cultures.     

Electrical Impedance Tomography of Electrolysis

The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT). The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations.     

Permeability changes in membranes of Neurospora crassa after freezing and thawing.

Conidia of Neurospora crassa which are in different physiological states show different rates of survival after freezing and thawing. [¹⁴C]adenine uptake by frozen and thawed conidia in different physiological states show a correlation with their survival. The uptake method was extended to study the survival of mycelium in log phase and stationary phase. From the uptake data it appears that log phase mycelium is extremely sensitive to all rates of freezing and thawing studied, while the stationary phase mycelium showed slight tolerance to freezing, if freezing was done at a slow rate. A study of the efflux of labeled compounds from the conidia in various physiological states or from the mycelia after freezing and thawing showed that, although efflux followed the same general trend as survival in conidia, it did not relate to the survival in mycelium, suggesting that the death of conidia or mycelium in the freeze-thaw treatments is not due to efflux of compounds.     

长白山不同海拔白桦幼苗移栽至同一生境的光合及反射光谱特性

环境是影响植物生理性状的主要因素之一,通过改变植物的生长环境来研究植物生理性状的改变是目前研究植物生理生态的热点,而高海拔地区多样的环境为研究物种适应环境变化提供了良好的实验条件。本研究通过移栽的技术手段,将分布在海拔750 m、海拔1200 m和海拔1400 m的3~5年生白桦幼苗移植到海拔750 m相同的林下环境条件下,将3种白桦移栽幼苗和野生白桦幼苗的光响应参数、光谱反射率以及光谱反射指数进行对比研究,分析移栽初期和移栽一年后植物生理性状的异同,探索白桦幼苗迁入新环境的适应性。研究结果表明:移栽初期,通过对比不同海拔来源的白桦移栽幼苗彼此之间各项生理性状以及与原海拔野生白桦幼苗的生理性状发现,包括最大净光合速率(A_(max))、气孔导度(G_s)、胞间CO_2浓度(C_i)在内的生理性状差异显著(P0.05),幼苗光谱反射指数差异性显著(P0.05)。经过一年的适应,不同海拔来源的白桦幼苗与移栽地海拔750 m野生白桦幼苗的生理性状之间差异不显著(P0.05),幼苗光谱反射指数差异性不显著(P0.05),而与原海拔野生幼苗生理性状之间差异显著(P0.05),幼苗光谱反射指数差异显著(P0.05)。在移栽初期,移栽幼苗的各项生理指标已经因环境的改变而发生变化,但仍保留原海拔野生幼苗的生理特性;移栽一年后,移栽幼苗逐渐适应环境,其相关生理性状发生改变,并趋同于移栽地野生白桦幼苗的生理性状。对比一个生长季前后白桦移栽幼苗生理性状的变化可以发现,白桦作为先锋种植物,在新迁入环境后具有良好的环境适应性,能通过调整生理性状适应新环境。研究对幼苗在林下的演替以及森林的更新具有借鉴意义。     

Detection of in vivo protein tyrosine nitration in petite mutant of Saccharomyces cerevisiae: Consequence of its formation and significance

Protein tyrosine nitration (PTN) is a selective post-translational modification often associated with physiological and pathophysiological conditions. Tyrosine is modified in the 3-position of the phenolic ring through the addition of a nitro group. In our previous study we first time showed that PTN occurs in vivo in Saccharomyces cerevisiae. In the present study we observed occurrence of PTN in petite mutant of S. cerevisiae which indicated that PTN is not absolutely dependent on functional mitochondria. Nitration of proteins in S. cerevisiae was also first time confirmed in immunohistochemical study using spheroplasts. Using proteosomal mutants Rpn10Δ, Pre9Δ, we first time showed that the fate of protein nitration in S. cerevisiae was not dependent on proteosomal clearing and probably played vital role in modulating signaling cascades. From our study it is evident that protein tyrosine nitration is a normal physiological event of S. cerevisiae.     

Biochemical Indices and Life Traits of Loggerhead Turtles (Caretta caretta) from Cape Verde Islands

The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study.     

Critical THI thresholds based on the physiological parameters of lactating dairy cows

The severity of heat stress conditions in high-yielding dairy cows is currently underestimated. The present study aimed to determine the heat load threshold of the temperature-humidity index (THI) on physiological parameters of lactating Holstein-Friesian cows under a continental climatic zone in Germany. Physiological parameter measurements, such as respiration rate (RR), measured hourly, and heart rate (HR) and rectal temperature (RT), both measured twice daily, were performed in a total of 139 multiparous cows on three randomly chosen measurement days per week. In addition, the ambient temperature and relative humidity of the barn were recorded every 5 min to calculate the current THI. The physiological parameter data were linked to the THI, and the heat load thresholds were determined using the broken-stick model. The heat load duration effect of each physiological parameter was obtained by regression analysis. Considering the increases in the physiological parameters, our study provided reliable data to determine heat load thresholds for lactating high-yielding dairy cows in a moderate climatic zone. The heat load threshold could be determined for RR in standing cows (THI = 70) and lying cows (THI = 65) and for HR (THI = 72) and RT (THI = 70) in standing cows. The heat load duration also demonstrated a significant effect on the increases in physiological parameters among dairy cows. In particular, the present study enabled a strategy to be devised to initiate heat mitigation in high-yielding dairy cows when they are exposed to THIs above 65.     

Determinants of Physiological and Perceived Physiological Stress Reactivity in Children and Adolescents

Aims

Abnormal physiological stress reactivity is increasingly investigated as a vulnerability marker for various physical and psychological health problems. However, studies are inconsistent in taking into account potential covariates that may influence the developing stress system. We systematically tested determinants (individual, developmental, environmental and substance use-related) of physiological and perceived physiological stress reactivity. We also examined the relation between physiological and perceived physiological stress reactivity.

Method

In a stratified sample of 363 children (7–12 years) and 344 adolescents (13–20 years) from the general population, we examined cortisol, heart rate, respiratory sinus arrhythmia and perceived physiological stress reactivity to a psychosocial stress procedure.

Results

Using multivariate linear regression models, we found that individual, developmental, environmental and substance use-related factors were related to each of the stress response indices. These determinant factors were different for each of the stress reactivity indices, and different in children versus adolescents. Perceived physiological stress reactivity predicted cortisol reactivity in adolescents only. All other relations between perceived physiological and physiological stress reactivity were not significant.

Conclusions

As physiological stress variables are often examined as vulnerability markers for the development of health problems, we maintain that it is essential that future studies take into consideration factors that may account for found relations. Our study provides an overview and indication of which variables should be considered in the investigation of the relation between physiological stress indices and illness.     

Life‐history strategy defends against disease and may select against physiological resistance

Host ecological traits may limit exposure to infectious disease, thereby generating the wide variation in disease incidence observed between host populations or species. The exclusion of disease by ecological traits may then allow selection to act against physiological defenses when they are costly to maintain in the absence of disease. This study investigates ecological resistance in the Silene-Microbotryum pathosystem. An estimated 80% of perennial Silene species host the anther-smut disease while no annuals harbor the disease in nature. Artificial inoculations of annual and perennial Silene plants, obtained from both natural and horticultural populations, demonstrate that the absence of disease in annuals is not explained by elevated physiological resistance. The annual habit is thus a powerful form of ecological defense against anther smut. Moreover, the higher susceptibility of annual species to anther smut relative to perennials supports the hypothesis of a loss of costly physiological resistance under ecological protection. The observation in annuals that physiological susceptibility is correlated with lower rates of flowering (i.e., lower fitness) suggests that variation in physiological resistance is costly in the absence of disease, even in a naїve Silene species. The absence of disease in natural populations of annuals combined with their high physiological susceptibility attest to the strength of host ecology in shaping the distribution of disease and to the dynamic nature of disease resistance.     

圈养东北虎血液生理参数的测定

东北虎(Panthera tigris altaica)是一种淑临灭绝的食肉动物,现已被列入IUCN濒危物种红色名录(Goodrich et al.,2015)。东北虎主要分布于俄罗斯远东地区、中国东北地区和朝鲜的北部(Kitchener et al.,2017)。根据中俄边境地区的野生东北虎数量调查统计,该地区生存着成年老虎39只和幼虎22只(Matiukhina et al., 2016)。     

Towards the development of an ecophysiological Daphnia model to examine effects of toxicity and nutrition

Freshwater ecosystems are highly susceptible to mercury (Hg) deposition, which impacts biotic health and leads to serious consequences through biomagnification. The keystone zooplankter, Daphnia, exerts disproportionate effects on food web dynamics, displaying high sensitivity to natural stressors, and thus serving as an indicator of the broader impairments of aquatic ecosystems. Combined with metabolomics, the study of metabolites and their chemical processes, we have developed a model that attempts to elucidate the interactive effects of Hg toxicity and nutrition on phytoplankton-Daphnia relationships. Our model stipulates a physiological hierarchy, prioritizing different metabolic processes in the order of neurological functions, bioenergetics, osmoregulatory maintenance, waste management, and growth investments. Daphnia resilience is controlled by both food quantity and quality and each physiological process is modulated by the somatic levels of different metabolites. By enriching food with metabolites associated with neurological and energetic physiological pathways, effects of toxicity can be alleviated. Specifically, we demonstrate that metabolites associated with bioenergetics (carbohydrates, fats, proteins, and phosphorus) confer the greatest resilience to physiological changes induced by toxicity. Prey-predator dynamics can change significantly due to the detrimental impacts of toxicity on daphnid physiology and unfavourable nutritional stoichiometry. Under conditions of poor nutrition and extreme toxicity, our model demonstrates that daphnid populations may collapse and thus phytoplankton could escape intense grazing pressure. Founded upon the premise that response to stress can be more rapidly detected at the metabolic level, our study offers a new perspective to develop bioindicator systems and early warning signals for more efficient environmental monitoring.     

Physiological relaxation induced by horticultural activity: transplanting work using flowering plants

Background

Despite increasing attention and a growing volume of research data, little physiological evidence is available on the benefits of horticultural activity and the different effects on individuals. Therefore, the aim of the present study was to investigate the physiological effects of horticultural activity and to examine how differences in personality alter these effects.

Results

The effects of transplanting real flowers (horticultural activity) and handling artificial flowers (control activity) on human physiological activity were compared. On the first day, eight participants engaged in horticultural activity and another eight in the control activity. On the second day, participants switched roles. Participants’ physiological conditions during each activity were assessed by measuring the heart rate and heart rate variability (HRV). Psychological responses, which were measured using a semantic differential rating scale, showed that the horticultural activity promoted comfortable, soothed, and natural feelings, compared to the control activity. Analysis of physiological responses using two-way repeated measures analysis of variance (ANOVA) revealed that sympathetic nervous activity significantly decreased in the late time period (11 to 15 minutes) of horticultural activity only in the type A group.

Conclusions

This study supports the fact that the horticultural activity can enhance psychological and physiological relaxation effects, although these physiological effects can differ among individuals with different personalities.     

THE EVOLUTIONARY RADIATION OF DIVERSE OSMOTOLERANT PHYSIOLOGIES IN KILLIFISH (FUNDULUS SP.)

Fish have radiated to exploit diverse habitats, but little is known about the evolutionary lability and directionality of associated physiological specialization. Killifish of the genus Fundulus present a compelling system to explore the evolution of osmotic tolerance because closely related species have evolved to occupy most osmotic niches, and physiological osmotic tolerance data are available for most species. This study seeks to determine the number of times, and the rate at which, alternate osmotic tolerance physiologies have evolved, and to determine the directionality of physiological transitions, by mapping comparative physiology data to a molecular phylogeny for the genus. Character mapping and phylogeographic inference indicate that freshwater tolerance is derived, can evolve rapidly, has evolved several times within the genus, and that variation in osmotic tolerance contributes to defining species distributions. The derivation of alternate physiologies within Fundulus appears associated with contraction of physiological plasticity rather than shifts in tolerance ranges, and the degree of contraction is surprisingly similar across convergent physiological types. The rate of physiological transition is relatively high within Fundulus compared to other taxa, but directionality from high salt tolerance to intolerance appears to be the rule. Together, these comparative physiology and phylogenetic data yield insight into the patterns of evolution of ecological specialization.     

In Vitro Effects of Different Resveratrol Concentrations on the Structural State of Mitochondrial Membranes Isolated from Pea Leaves

In this study, the effects of different concentrations of antioxidant resveratrol on microviscosity of mitochondrial membranes isolated from pea leaves were investigated. It was shown that resveratrol in physiological (5 × 10^–6 M) and ultralow (5 × 10^–14 M) doses changed the microviscosity and altered the structure of the membrane lipid bilayer. This antioxidant is thought to affect the activity of membrane proteins due to altered structures of lipid molecules that surround them and, in turn, influence mitochondrial activity and function. No change was found in the range between physiological and ultralow doses, which is a “dead” zone. Moreover, resveratrol in physiological concentrations was found to shift thermally induced structural transition to the lower temperature region; therefore, it can interfere with the normal regulation of natural processes