Resistance Parameters Research Articles

The role of bioimpedancemetry in optimizing antihypertensive therapy in patients with high peripheral resistance

Background: Hypertension remains a leading global health concern, particularly in patients with high peripheral resistance, where therapeutic optimization poses a significant challenge. Bioimpedancemetry offers a novel approach to individualize antihypertensive therapy by providing insights into vascular resistance and fluid distribution. This study aimed to evaluate the role of bioimpedancemetry in optimizing antihypertensive therapy in patients with high peripheral resistance. Methods: A total of 62 patients with hypertension (29–60 years, mean age 48.75 ± 1.6 years; 30 women) were included in the study. Bioimpedancemetry was employed to assess vascular resistance and fluid balance at baseline and during therapy. Based on the findings, antihypertensive therapy was tailored to individual needs. Blood pressure control, peripheral resistance, and clinical outcomes were evaluated over six months. Results: Bioimpedancemetry-guided therapy resulted in a significant reduction in mean arterial blood pressure (p < 0.05) and peripheral resistance (p < 0.01) compared to standard therapy. Women demonstrated greater improvement in vascular resistance parameters (p < 0.05) than men. Additionally, therapy adjustments based on bioimpedance data improved patient adherence and overall therapeutic efficacy. No adverse effects related to therapy adjustments were reported. Conclusion: The integration of bioimpedancemetry in managing patients with hypertension and high peripheral resistance significantly enhances therapeutic outcomes by enabling personalized treatment strategies. This method holds promise for broader clinical application in hypertension management.

Phenotypic evaluation of Ptb 33 introgressed rice lines for resistance to brown planthopper, Nilaparvata lugens (Stål)

Brown planthopper (BPH), Nilaparvata lugens (Stal) continues its dominantce as an important pest in rice and cause considerable yield loss. Ptb 33 is a well-known source of resistance to BPH. Introgressed lines from Ptb 33 were evaluated against BPH using various parameters of resistant mechanisms. Initial screening was done by protray and modified seedbox screening tests. Eight entries illustrate resistance to BPH in mass screening. Further experiments assessed the mechanisms viz., antibiosis, antixenosis and tolerance in selected resistant entries. Antibiosis studies revealed reduced honeydew excretion, lower nymphal survival rates and prolonged developmental periods in resistant lines compared to the susceptible check. Antixenosis was evaluated through nymphal settling preference tests, with resistant entries showing reduced BPH attraction over time. Tolerance parameters, including Functional Plant Loss Index (FPLI) and Plant Dry Weight Loss Index (PDWLI), indicated varying levels of resistance among the introgressed lines. Among the entries identified as resistant through screening, FSR-3 exhibited strong resistance across all three mechanisms, while X21302-145 showed excellent antibiosis but poor tolerance character. Correlation analysis revealed significant interrelation between various resistance parameters. The study identifies promising BPH-resistant rice lines and elucidates their underlying resistance mechanisms, contributing valuable insights for rice breeding programs in developing durable BPH-resistant cultivars.

Characterization and Optimization of Boride Coatings on AISI 1137 Steel: Enhancing Surface Properties and Wear Resistance

This study investigates the optimization of boron coating parameters for medium-carbon steels, specifically AISI 1137, and their subsequent effects on mechanical properties, which are crucial for industrial applications. Despite extensive research on boronizing processes, an understanding of the optimal conditions that enhance wear resistance and hardness while maintaining structural integrity is still lacking. To address this gap, we systematically examined the impact of boronizing temperatures (850 °C and 950 °C) and durations (2, 4, and 8 h) on the structural and mechanical properties of AISI 1137 steel. Our findings indicate the need for improved surface properties in medium-carbon steels used in demanding environments, such as automotive and machinery components. The boronizing process was carried out using Ekabor 1 powder, with characterization performed through optical microscopy, pin-on-disk wear tests, and Vickers hardness analysis. Results showed that the thickness of the boronized layer ranged from 50.6 μm to 64.8 μm, with wear resistance increasing by 1.8 to 3.9 times at 950 °C compared to at 850 °C. The measured hardness of the boronized surface layers varied between 1963.7 HV and 219.3 HV, decreasing from the boronized layer toward the base material. The optimal parameters for wear resistance and hardness were found to be a temperature of 950 °C and a duration of 8 h, facilitating the formation of FeB and Fe2B phases, which significantly enhanced the steel’s mechanical properties. This research provides valuable insights into the boronizing process and establishes a foundation for the optimizing of surface treatments to extend the lifespan and performance of medium-carbon steels in industrial use.

DEEPLY PENETRATING GPR SURVEYS: EXPERIENCE OF KINEMATIC DATA INTERPRETATION

Experimental studies were carried out in the permafrost zone using the method of reflected electromagnetic waves based on multi-offset data acquisition with common distance-point (REW CDP), referred to here for short as electromagnetic CDP (ECDP). Comparison of the results of processing several ECDP hodographs taken within the same site at a distance of up to 6 km, specifically, the vertical velocity distributions in the 0–10 μs time intercept reveals some similarities in the structure of permafrost and electrical properties of the underlying rocks, which agrees with the drilling data. The velocity analysis data served as the basis for the geophysical model of the CDP stacked section built as a 500 m deep “virtual borehole” with a step size of 50 ns (2–5 m), describing the change in the electrical resistivity parameter with depth.

INVESTIGATION OF THE DENSITY OF CCCM AND ITS INFLUENCE ON SPECIFIC VOLUME ELECTRICAL RESISTIVITY

This article investigates the structure and properties of carbon-carbon composite materials (CCCM), where the carbon matrix is formed by the deposition of pyrolytic carbon in the porous volume of a carbon fiber preform using thermogradient gas-phase pyrolysis densification technologies. The results of studying the apparent density of CCCM by hydrostatic methods and its influence on the specific volume electrical resistivity of the material are presented. The conducted study established that the specific volume electrical resistivity of CCCM significantly depends on a number of factors, one of which is the material density. An increase in the apparent density of the material leads to a decrease in its porosity, which, in turn, affects the decrease in electrical resistance. It is emphasized that density control becomes a key factor in ensuring optimal electrical conductivity of carbon-carbon composite materials. It is shown that the densification of CCCM significantly improves the structure of blanks and crucibles, increasing their physical and operational characteristics. This makes them more suitable for use in high-temperature conditions, aggressive environments, in the production of heat-resistant components and other high-tech areas. Repeated densification of CCCM revealed a significant impact on the quality of the material. It is shown that an increase in density after additional densification leads to a decrease in porosity, improvement of mechanical properties and a change in the pore distribution in the material, which positively affects its porosity and strength. Bench tests of model samples made of CCCM showed that an increase in the apparent density of the material leads to a decrease in its electrical resistance. To ensure control in industrial practice, an effective and affordable method for assessing the degree of completion of crystalline transformations and determining the degree of graphitization during high-temperature treatment of carbon materials is recommended to compare the specific volume electrical resistivity of the working sample with the reference one. The importance of controlling the parameters of density, porosity, and electrical resistance to optimize technological processes and ensure high quality of final products is emphasized. The obtained data can be useful for applications in various industries.

Serum Zinc-Alpha-2 Glycoprotein and Zinc Levels and Their Relationship with Insulin Resistance and Biochemical Parameters in Overweight and Obese Children.

The biological role of zinc-alpha 2-glycoprotein (ZAG) has been associated with lipid mobilization, although this is not entirely clear. The study's aim was to examine the serum levels of ZAG and zinc (Zn) and the Zn/ZAG in a population of children with overweight (OW) and obesity (OB), and their relationship with biochemical parameters. Our study was a cross-sectional analysis of a group of Mexican children aged 6-10 (n = 72). We analyzed anthropometric data and biochemical parameters, including fasting plasma glucose (FPG), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides (TG), total cholesterol (TC), insulin, and homeostatic model assessment insulin resistance (HOMA-IR). ZAG protein levels were measured using enzyme-linked immunosorbent assay (ELISA), and serum zinc (Zn) levels were quantified using inductively coupled plasma mass spectrometry (ICP-MS). The Zn values indicate a statistically significant difference between normal weight (NW) and OW/OB children with Zn concentrations were 91µg/dL for NW and 66µg/dL for OW/OB children. ZAG values did not show significant differences between NW and OW/OB, and values were 2.1mg/dL and 2.3mg/dL, respectively. The Zn/ZAG ratio was lower in the OW/OB compared to the NW (p = 0.05). Correlations were found between FPG and Zn (p = 0.004) in NW boys, and ZAG (p = 0.046) in OW/OB boys, as well as a negative correlation between insulin and Zn in NW children of both sexes. HOMA-IR shows correlations between Zn (p = 0.008) in OW/OB boys, and ZAG (p = 0.010) in the OW/OB girls. Additionally, correlations were observed between LDLc, TG, and BMIz with Zn and ZAG in the boys. In the same way, we also found that girls with OW/OB had a Zn/ZAG ratio of - 2.32 (p = 0.043) compared to NW boys. In conclusion, our findings highlight the significant roles of Zn and ZAG in glucose and lipid metabolism. Furthermore, Zn/ZAG ratio may provide insights into nutritional deficiencies, adiposity, and metabolic health. However, further studies are necessary to validate our results.

Alterations in Biomarkers Associated with Cardiovascular Health and Obesity with Short-Term Lifestyle Changes in Overweight Women: The Role of Exercise and Diet.

Background and Objectives: In this study, the effects of an eight-week exercise and nutrition program on blood lipids, glucose, insulin, insulin resistance (HOMA-IR), leptin, ghrelin, irisin, malondialdehyde (MDA), and Growth Differentiation Factor 15 (GDF15) in overweight women were investigated. Materials and Methods: A total of 48 women volunteers participated in this study. The participants were randomly divided into four groups: control (C), exercise (E), nutrition (N), exercise + nutrition (E + N). While no intervention was applied to group C, the other groups participated in the predetermined programs for 8 weeks. At the beginning and end of this study, body composition was measured and blood samples were taken. Results: It was determined that the body composition components, lipid profile indicators, insulin, glucose, insulin resistance, leptin, ghrelin, irisin, and MDA parameters examined in this study showed positive changes in the intervention groups. Group E had a greater effect on body muscle percentage, MDA, and irisin levels, while group N had a greater effect on blood lipids and ghrelin levels. Conclusions: As a result, it is thought that lifestyle changes are important to improve cardiovascular health and combat obesity, and that maintaining a healthy diet together with exercise may be more effective.

DETERMINATION OF THE STABILITY PERIOD OF TURNING CUTTERS FOR HEAVY MACHINE TOOLS

To determine the optimal cutting modes under conditions of increased requirements for the stability of technological processes, it is necessary to take into account the value of the tool life with a given probability. In this paper, the stability dependence for prefabricated cutters used on heavy machine tools with maximum diameters Dmax = 1250-2500 mm is specified using the group argumentation method. The study presents a new mathematical model that establishes the relationship between tool fracture resistance and key operational parameters. This model incorporates the probabilistic nature of tool performance, which allows for a more accurate assessment of the impact of part size variation, cutting conditions, and process variability. The proposed relationship facilitates the determination of cutting modes that not only increase tool stability but also ensure the reliability and efficiency of heavy machine tools in industrial environments. This mathematical dependence makes it possible to take into account the variation of workpiece parameters and cutting modes, which is especially important when working with large-sized parts on heavy-duty machine tools. The results of the study are of practical importance for industry, as they make it possible to increase the sustainability and productivity of technological processes.

Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem

Abstract. Few studies have investigated the performance of land surface models for semiarid Mediterranean forests. This study aims to parameterize and test the performance of the Noah-MP land surface model for an eastern Mediterranean ecosystem. To this end, we calibrated the model for root zone soil moisture and transpiration of two conifer species, Pinus brutia, and Cupressus sempervirens, in a plantation forest on the Mediterranean island of Cyprus. The study area has a long-term average annual rainfall of 315 mm. Observations from 4 sap flow and 48 soil moisture sensors, for the period from December 2020 to June 2022, were used for model parameterization. A local sensitivity analysis found that the surface infiltration (REFKDT), hydraulic conductivity (SATDK), and stomatal resistance (RSMIN) parameters had the highest impacts on the water balance components (soil evaporation, tree transpiration, surface runoff, and drainage). The model performed better during the wetter 9-month validation period (379 mm rain) than during the drier 10-month calibration period (175 mm rain). Average soil moisture in the top 60 cm of the soil profile was reasonably well captured for both species (daily Nash–Sutcliffe efficiency > 0.80 for validation). Among the three soil layers, the second layer (20–40 cm) showed better simulation performance during both periods and for both species. The model exhibited limitations with respect to simulating transpiration, particularly during the drier calibration period. The inclusion of a root distribution function in the model, along with the monitoring of soil moisture below the 60 cm soil depth in the field, could improve the accuracy of model simulations in such water-limited ecosystems.

Summary of the results of field and laboratory studies of hydraulic resistance during channel bending

The reliability of channel forecasts, performed using mathematical modeling methods in the design of engineering activities on shipping rivers, largely depends on the accuracy of the assessment of hydraulic resistance and sediment transport parameters. Therefore, the hydraulic resistance of natural channels is one of the largest problems in the dynamics of channel flows and is the object of close attention of scientists. In the resistance of natural channels, roughness appears in three forms: the first of them is the roughness of the granular surface of the bottom; the second is the roughness created by boulders and the third type is the roughness of microforms: ripples and ridges. Channel mesoforms also contribute to the resistance to water movement: spits, side streams, middle streams, islands, bends of the channel and such complex formations as riffles. This type of resistance is usually called the resistance of the channel form. The resistance of the natural channel shape due to the movement and deformation of mesoforms can change significantly over time. The complexity and insufficient study of this issue significantly limit the possibilities of a theoretical approach to its solution. Therefore, the obtained results are mainly empirical or semiempirical in nature. The paper presents the results of experimental and field studies that allowed us to identify the main features of flow movement in winding sections of rivers. One of the features of flow movement at channel turns is the possibility of additional energy losses. The total resistance of a curved section of a channel is made up of three main parts: the resistance of the granular surface of the bottom, the resistance of the bottom ridges, and the resistance of the channel shape. The additional resistance created by the bend depends on the curvature of the channel, the rate of change in depth along the length of the bend, and also reflects the impact of side streams formed near the convex bank on the flow.

Three‐dimensional modeling of electromagnetic field and fluid flow during solidification of an aluminum alloy in a pulsed magnetic field

AbstractThree‐dimensional finite element models were built to describe the distribution of electromagnetic fields and fluid fields under a low frequency low voltage time‐dependent pulsed magnetic field. The simulation results showed that eddy current circling around the axis of the melt can be induced by pulsed magnetic field. Periodic positive‐negative Lorentz force in the melt was induced from the interaction between the current and magnetic field. The effects generated by the pulsed magnetic field included vibration, fluid flow and Joule heat. The melt flowed in the form of a multi‐circle and the fluid velocity was composed of a base component and a pulse component. The temperature in the melt was homogeneous because of the fluid flow. Melt temperatures were measured and compared with the simulated results during solidification process of aluminum alloy A356 (Al−Si alloy), which qualitatively confirmed the decrease of temperature gradient. Moreover, the effects of material resistivity and electromagnetic parameters of the pulsed magnetic field were investigated. Materials with smaller resistivity took larger electromagnetic force. The fluid flowed much faster under larger excitation current density and frequency. Finally, the grain refinement mechanisms under the pulsed magnetic field were analyzed.

ИССЛЕДОВАНИЕ СВОЙСТВ РЕЗИН НА ОСНОВЕ СКЭПТ, НАПОЛНЕННЫХ ПОЛИАКРИЛОНИТРИЛОМ

The article studies rubber mixtures based on EPDM with polyacrylonitrile (PAN), including those previously subjected to partial pyrolysis. Pyrolysis, oil resistance, coke number and physico-mechanical parameters of the studied rubbers were studied. It is shown that the introduction of PAN makes it possible to improve the resistance of rubbers to high-temperature heating and the oil resistance of vulcanizates.

Do not ignore mouth breathing syndrome: respiratory functions are affected in early childhood.

Impulse oscillometry (IOS) is a useful test for measuring pulmonary resistance and reactance from the early ages. We aimed to investigate the etiological factors of mouth breathing syndrome (MB), its effects on respiratory functions, and to compare the results with those of children with nasal breathing (NB). This prospective cross-sectional study investigated children aged 3-7 years with MB (n=202) and NB (n=127) admitted to the pediatric allergy clinic between January 2023-2024. The MB group was evaluated for etiological factors by means of otorhinolaryngological examination. Respiratory function tests were evaluated using IOS and were repeated two months after appropriate treatment. Adenoid hypertrophy (AH-44.0%), allergic rhinitis (AR-11.3%) and AH co-existent with AR (34.6%) were the principal causes of MB. Entire airway resistance was higher, upper and lower airway reactance were lower in the MB group compared to the NB group. No difference was detected in terms of IOS parameters between the first and second visits of MB group. Upper and entire airway resistance parameters were higher in children with AH and AH co-existent with AR groups compared to the non-obstructive group. Entire airway resistance was higher, upper and lower airway reactance were lower, in children with adenoid size>50% compared to those with adenoid size mouth breathing, allergic rhinitis, adenoids, respiratory function test, pediatrics.

Wellbore Stability Analysis Based on the Combination of Geomechanical and Petrophysical Studies

Determining the physical and mechanical properties of rocks is crucial for planning drilling operations. Ignoring geomechanical studies and tools has led to millions of dollars in additional costs related to drilling, meshwork optimization, production optimization, casing collapse, and other issues. These costs can be managed with a thorough geomechanical study. Additionally, some costs may not be apparent in the short term but will become significant over the life of the field. Long-term reservoir management is essential to control these costs. Issues such as reservoir compression, rock cover fractures, and gas storage, if neglected in the short term, can lead to substantial and irreparable damage to the reservoir over time. The "geomechanical model" is fundamental to geomechanical studies, particularly regarding wellbore stability. Given the importance of reservoir geomechanics and petrophysics, this research investigates wellbore stability analysis by combining geomechanical and petrophysical studies through the construction of a one-dimensional geomechanical model of the well. First, the dynamic geomechanical coefficients of the rock for the studied depth range were calculated from wells and petrophysical charts. Then, the static geomechanical coefficients of the rock were estimated based on laboratory-developed relationships. Subsequently, rock mechanics test results were used to estimate rock resistance parameters. The pore pressure was estimated using the compressibility and Eaton methods for the studied range from Well No. 5. Comparing the results of these two methods with RFT test data indicated that the compressibility method is more accurate than Eaton’s method. By estimating the in situ and induced stresses in the well's studied area, the lower and upper limits of the safe mud weight were calculated using the Mohr-Coulomb and Hooke-Brown criteria. Comparison of the results showed that the Mohr-Coulomb criterion is more accurate and, moreover, more conservative than the Hooke-Brown method.

Does Antibiotic Use Contribute to Biofilm Resistance in Sink Drains? A Case Study from Four German Hospital Wards.

Backgound. As biofilms are known to harbour (multi-)resistant species, their presence in health settings must be considered critical. Although there is evidence that bacteria spread from drains to the outside, there is still a lack of research data focusing on drain biofilms from hospitals. Methods. We sampled biofilms from various wards of Helios Hospital Krefeld (Germany), where comprehensive antibiotic consumption data were available. Biofilms were analysed by cell counting, isolation of relevant bacterial groups and genetic and phenotypical resistance parameters. Data were correlated with the prescribed antibiotics of the respective ward. Furthermore, an ex situ biofilm model was employed to investigate the influence of sub-inhibitory antibiotics on the bacterial community and the prevalence of class 1 integrons. Results. Our results show that every ward harboured medically relevant bacterial species. While no significant differences were found in cell counts, the median prevalence of the resistance marker gene intI1 correlated with the amount of prescribed antibiotics. In contrast, phenotypical resistances showed no similar tendency. In addition, melting curve analysis data and changes in intI1 prevalence show that the composition of the bacterial community shifted depending on the biofilm and antibiotic. Conclusions. To the best of our knowledge, our study is the first considering possible correlations between the consumption data of hospital wards and resistances in drain biofilms the way we did. Based on our results, we conclude that sub-inhibitory concentrations of antibiotics have no general effect on biofilms in terms of bacterial community shift and occurrence of antibiotic-resistant species. Amongst other things, the effect depends on the initial composition of the bacterial community, the antibiotic used and the intrinsic bacterial resistance, e.g., prevalence of class 1 integrons.

Effect of feed rate during induction hardening on the hardening depth, microstructure, and wear properties of tool-grade steel work roll

Rolls are the most critical yet vulnerable parts of cold rolling mills. It is crucial for them to withstand long rolling campaigns without losing surface roughness or incurring damage. Newly developed rolls are made from tool-grade steel with high roughness, lower wear, and high damage resistance. One of the most important advantages is the elimination of the need for chrome plating, which is currently widely used on standard steel rolls but is ecologically harmful. We investigated a type of steel with 8% chromium for use in cold rolling using light optical microscopy (LOM), X-ray crystallography (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), hardness measurements, and tribological tests. In this study, a roll with a diameter of 325 mm was electro-slag remelted and forged, machined to a diameter of 305 mm, and quenched and tempered to simulate industrial roll production. A forged roll was induction heated and hardened at four different feed rates (i.e., 24 mm/min, 30 mm/min, 36 mm/min, and 42 mm/min), tempered at 515℃ for 24h and again at 480℃ for 24h, and dissected for in-depth analysis. We identified a clear relationship between the feed rate of the roll during induction hardening and the depth of hardness, the sizes of carbides, and the wear properties of the roll. By reducing the feed rate of the roll through the inductor, we increased the depth of the hardened layer from 16 mm (at a feed rate of 36 mm/min) to 25 mm (at a feed rate of 24 mm/min), which is a 56.25% increase. Such an increase is expected to extend the lifespan of the working roll without having negative effects on the wear resistance and other important parameters. XRD analysis showed that the sample had a 0.4% residual austenite, which means it had a significantly lower risk of roll damage during operation than standard steel grades

Preparation of 3DOM PI–Ion Gel Composite Electrolyte Membranes for Li Metal Batteries

The electrolyte used in Li metal batteries (LMBs) contributes to high cycle performance, coulombic efficiency and safety. In particular, highly flammable electrolytes limit an operating temperature of LMBs around room temperature to keep safety, so that an introduction of cooling system is necessary, resulting in a reduction of the energy density of LMBs. Therefore, a use of safer electrolytes is required. Ion gel (IG) electrolytes have attracted attention as a candidate for electrolytes with high safety. Ionic liquid (IL) electrolytes have been incorporated in a polymer matrix. A large amount of polymer matrix has been needed to prepare thinner membranes of IG electrolytes, due to achieve high mechanical strength of mebranes. In contrast, the amount of polymer matrix is minimized to achieve higher ionic conductivity. This trade-off relationship between mechanical strength and ionic conductivity of IG electrolyte membranes must be solved by different approaches. This problem may be solved by IG electrolyte membranes incorporated into a separator framework. This separator does not contributes only to mechanical strength and ionic conductivity, but also to electrochemical performance of Li metal anode, such as Li metal deposition and dissolution and its coulombic efficiency. Therefore, a selection of separator used in the composite electrolyte membrane is very important. We have developed a three-dimensionally ordered macroporous polyimide (3DOM PI) separator that has a good affinity with IL electrolytes. In this study, the mechanical strength and ionic conductivity of the IG electrolyte membranes are improved by using a 3DOM PI separator as the framework. In addition, the more uniform porous structure of the 3DOM PI separator provides a high reversibility of Li metal dissolution and deposition. Three types of electrolytes were used in this study: pristine IG electrolyte membrane, surfactant-coated polypropylene (PP 25 μm)–IG composite electrolyte membrane, and 3DOM PI (30 μm) –IG composite electrolyte membrane. Lithium bis(fluorosulfonyl)imide and N-metyl-N-Propylpyrrolidinium bis(fluorosulfonyl)imide mixture with a molar ratio 1:1 was used as the IL electrolyte. Polymeric precursor solution for IG composite electrolyte was prepared from methyl methacrylate (MMA), 5 wt% of ethylene glycol dimethacrylate (EDGMA) to MMA, and 0.2 wt.% of 2,2’-azobis(isobutyronitrile) (AIBN) to MMA. The polymeric precursor was casted on the polytetrafluoroethylene (PTFE) sheet, PP separator, or 3DOM PI separator and sandwiched between PTFE sheets and then heated at 75 °C for 12 hours for polymerization in the separator. In the case of pristine IG electrolyte, the thickness of the self-standing membrane was at least 300 μm. The 3DOM PI separator was prepared by using a colloidal template method. An ionic conductivity measurement was performed to investigate an effect of separators on ionic conductivities of membranes. Figure 1 (a) shows the Arrhenius plots of the ionic conductivity of the membranes. The pristine IG electrolyte membrane exhibited the highest ionic conductivity, followed by 3DOM–IG composite membrane and PP–IG composite membrane. There was no significant difference in the slope of Arrhenius plots, indicating that the ionic conduction mechanisms of these electrolytes were not different each other. The unique pore structure of the 3DOM PI separator provided higher ionic conductivity than the surfactant-coated PP separator. The thickness of the membrane between the anode and cathode is an important parameter for an internal resistance of cell. Therefore, a conductance of real electrolyte membranes should be discussed. Figure 1 (b) shows the Arrhenius plots of the conductance of the electrolytes. The 3DOM PI–IG composite electrolyte exhibited both higher mechanical strength and conductance compared with those of other electrolytes. In conclusion, the composite electrolyte membrane between 3DOM-PI and IG is the most promising separator. Figure 1

Compact Modeling of Base Current High Injection Effect in SiGe HBTs

In bipolar transistor compact modeling, the forward mode base current typically consists of three components: space-charge recombination, back injection into the emitter, and neutral-base-recombination (NBR). At medium and high base-emitter voltages (VBE), the emitter back injection and NBR components dominate, and both increase exponentially with VBE. Deviation from the ideal behavior occurs at high VBE due to parasitic base and emitter resistance or self-heating.However, in many SiGe HBTs, standard compact models fail to capture experimentally observed IB-VBE characteristics, where the base current (IB) exhibits a high injection behavior that is more evident at lower collector-base voltages (VCB), as shown in Fig. 1. The simulation is done with Mextram 505.2 with resistance and self-heating parameters already calibrated. At a relatively low VBE of 0.72 V, the measured IB starts to bend downward compared to its typical behavior shown by the model, causing the increase of beta with VBE from 0.72 to 0.82 V. Parameter optimization cannot possibly fit silicon data and a new base current model is called for.Similar behavior has been observed by other groups and attributed to carbon-induced NBR [1]-[3]. Interestingly, the onset of this IB high injection occurs at a lower VBE than the onset of collector current (IC) high injection, which is typically due to Kirk's effect or quasi-saturation effect. Such IB high injection behavior also exhibits a complex VCB dependence. The change of IB-VBE slope is less visible at higher VCB due to self-heating, which increases IB.We present a recently developed compact model of base current that models this high-injection effect. The foundation of the high-injection effect model is an analytical expression of the neutral base recombination rate applicable to all injection levels derived from SiGe HBT NBR physics. Based on experimental data measured on devices with different geometries, we model both the area component and peripheral component with separate temperature coefficients. The area component is subject to neutral base width modulation modeled by the same parameters used for the Early effect. A quasi-saturation-induced component is included to model the NBR after the electrical neutral base pushes out at high current densities. The quasi-saturation component has its dedicated parameters to account for the NBR at the SiGe-base/Si-substrate epitaxial growth interface discussed in [4] and [5]. This component comes into play at higher VBE.Fig. 2 demonstrates the new model's capability in capturing the measured IB high injection behavior and its complex VCB dependence, as well as the much-improved fitting of the beta vs. VBE characteristics. The inclusion of the NBR high-injection effect in the base current model enables more accurate modeling of SiGe HBTs. The model has been implemented in Mextram 505.3 and later versions [6].

Change in adiposity indices after 1 year of peritoneal dialysis: a single-center cohort study.

Weight gain is common after starting peritoneal dialysis (PD). Several adiposity indices have been developed recently as potential indicators of visceral adiposity and lipid accumulation. We aim to investigate the prevalence and prognostic implications of the change in adiposity indices after 1year of PD. We recruited 110 patients treated with PD for 12months. Adiposity indices, including triglyceride glucose index, lipid accumulation product, visceral adiposity index and conicity index, were measured at baseline and then 1year after PD started. The relation between their changes (Δ) and other clinical and biochemical parameters, as well as survival and hospitalization rates were analyzed. After 1year of PD, more than half of the patients had increased adiposity indices. The change in adipose tissue mass significantly correlated with the concomitant changes in triglyceride glucose index (ΔTyGI) (r=0.25, P =.01), lipid accumulation product (ΔLAP) (r=0.27, P =.007) and visceral adiposity index (ΔVAI) (r=0.26, P =.01). ΔTyGI significantly correlated with the change in insulin resistance as represented by homeostasis model assessment of insulin resistance (HOMA-IR) (r=0.22, P =.02), while ΔLAP and change in conicity index (ΔCI) correlated with the changes in various anthropometric parameters. However, no indices variation was associated with patient survival, technique survival or hospitalization rate. Increased adiposity indices were common after 1year of PD. The changes in adiposity indices had variable correlation with the change in adipose tissue mass, insulin resistance and anthropometric parameters. Further studies are required to identify simple metabolic parameters with a prognostic impact that could be suitable for serial monitoring.

Исследование проницаемости эпителиального слоя клеток TEER методом

The study investigated the electrical characteristics of the Caco-2 cellular layer grown on a cellulose acetate membrane using impedance spectroscopy and cyclic voltammetry methods. The effect of ethanol solutions of varying concentrations on the electrophysical properties of the cellular layer was studied. During measurements of the layer characteristics by the cyclic voltammetry method under direct current, it was found that its resistance before ethanol treatment was 642 kOhm. Treatment with a 25% ethanol solution increased this value to 645 kOhm, while 50% and 95% solutions decreased it to 505 kOhm and 373 kOhm, respectively. During the study of the cellular layer's properties using impedance spectroscopy with alternating current, dependencies of the real and imaginary parts of the resistance on the ethanol concentration in the treatment solution were obtained. The obtained data were used to construct Nyquist diagrams. Their analysis allowed for the proposal of an equivalent circuit describing the process of current flow through the studied system. The equivalent circuit included parameters of paracellular transport, membrane resistance and capacitance, as well as elements accounting for electrode polarization. As a result, values of capacitance and membrane layer resistance were obtained. It was established that the membrane layer capacitance changes under the influence of ethanol. When treated with a 50% ethanol solution, capacitance increases, indicating degradation of the cell membrane and a reduction in its barrier function. Treatment with a 95% solution led to a decrease in capacitance, which can be attributed to the compression of the cell layer, reducing the capacitance contribution to the system's overall conductivity. The results demonstrate the importance of quantitative analysis of cellular electrical parameters for studying their response to chemical stress and confirm the potential of such approaches in biomedicine for creating sensors and «organ-on-a-chip» systems.