Decrease In Resistance Research Articles

Improving Energy Storage and Nickel Manganese Cobalt Oxide Cathode Lifetime via a Tannic Acid/Iron (III) Metal Phenolic Network Coating

AbstractSurface coating lithium‐ion battery cathodes is a promising strategy to improve performance and mitigate cathode degradation. The coatings studied to date focus on either electronically or ionically conducting layers, which have been introduced to enhance the redox reactions of cathode particles, or oxide‐based physical protection layers limiting surface degradation. Such coatings require high‐temperature, time‐consuming synthesis processes, along with uncertainty in the specific interactions between these coatings and lithium ions. Here, metal‐phenolic network coated LiNi0.6Mn0.2Co0.2O2 (NMC) cathodes are, produced using naturally occurring polyphenols via a rapid one‐step assembly, improve cathode electrochemical performance. The performance improvement arises from the interaction between lithium ions and the coated layer, which enhances the lithium‐ion transport to the cathode. In half‐cell 1C rate cycling conditions, the modified cathode displays a 20% reduction in overpotential and a 54% decrease in interfacial resistance compared to the uncoated cathode. In a full‐cell format, the modified cathode exhibits a 10% increase in capacity and a 54% increase in lifespan for constant current cycling; in addition to a 5% increase in capacity and a 25% increase in lifespan for constant current‐constant voltage (CCCV) cycling. This work paves the way for improving cathode materials via eco‐friendly lithium‐ion attraction strategies.

Non-Destructive Testing of Concrete Materials from Piers: Evaluating Durability Through a Case Study

Concrete is currently the most used construction material, mainly due to its mechanical strength, chemical stability, and low cost. This material is affected by wear processes caused by the environment, which lead to a reduction in the useful life of the infrastructure in the long term. These wear processes can cause cracks, corrosion of reinforcing steel, loss of load capacity, and loss of concrete section, among other problems. Considering the above, it is necessary to carry out durability studies on concrete to determine the integrity conditions in which the infrastructure is found, the reasons for its deterioration, the environmental factors that affect it, and its useful life under these conditions, and develop restoration or protection plans. Generally, the durability studies include non-destructive testing such as ultrasonic pulse velocity, electrical resistivity, porosity measurement, and capillary absorption rate. These techniques make it possible to characterize the concrete and obtain information such as the total volume of pores, susceptibility to corrosion of the reinforcing steel, decrease in mechanical resistance, cracks, presence of humidity, and aggressive ions inside the concrete. In this work, two durability studies are presented with non-destructive tests carried out on active piers that are 20 and 40 years old. These are located in coastal areas in southern Mexico on the Gulf of Mexico side, with 80% average annual relative humidity, temperatures above 33 °C on average, high concentrations of salts, load handling, vibrations, flora and fauna typical of the marine ecosystem, etc. The results obtained reveal important information about the current state of the piers and the damage caused by the environment over time. This information allowed us to make decisions on preventive actions and develop appropriate and specific restoration projects for each pier.

Simultaneous determination of refined values of mobility, channel and contact resistance in organic field-effect transistors utilizing the four- and three-probe methods

Abstract Accurate determination of charge carrier mobility is a critical aspect in an organic field-effect transistor (OFET) as it is tightly correlated to the development of new materials, better device designs and improved fabrication methods. The presence of high contact resistance at the metal–organic semiconductor interface introduces an intrinsic error in the extraction of charge carrier mobility. In this report, electrical circuit analysis for the determination of the refined channel mobility, total contact resistance and channel resistance values is showcased for a poly(3-hexylthiophene) OFET with bottom-gate bottom-contact architecture. The process of determination is based on the combination of the conventional four-probe and three-probe measurement techniques. These two techniques are used in conjunction to assess refined mobility values in the channel region. This is followed by the determination of total contact resistance and channel resistances. The results show that, at a fixed drain current, mobility increases with the gate voltage while both the contact and channel resistances decrease.

A Method of Applying Mixtures to Optimize Grounding during Installation of Vertical Composite Grounding Devices

The article considers the method of using mixtures to optimize the electrophysical parameters of grounding devices in conjunction with vertical composite grounding conductors. It has been found that fluctuations in soil resistivity caused by changes in weather and climatic conditions can lead to instability of the ground loop resistance. The study shown that without appropriate measures, the resistance of the loop as a result of seasonal changes in soil properties may exceed acceptable values. This is fraught with deviations in the resistance to current spreading of grounding devices beyond the limits of acceptable parameters. To compensate for these fluctuations, a method is proposed to reduce the seasonality factor. Reducing seasonality plays an important role in ensuring the safety of service personnel and farm animals by maintaining the resistance of the grounding device within the limits of regulatory values. The authors discuss methods for artificially reducing the resistance of the ground loop, including increasing its size and using deep ground electrodes. The results of vertical electrode probing of the soil at the sites of grounding conductors are presented, the effect of humidity on the resistivity of the soil is shown, the influence of soil layering and the presence of moisture-saturated soil layers is considered. A method is proposed that allows the mixture to be introduced together with a vertical composite grounding device, the design of the coupling, tip and auxiliary device, experimental studies of the proposed designs are carried out and the results of measuring the current spreading resistance of such a grounding device with both standard and proposed couplings are presented. A comparison was made with a grounding device without the use of mixtures. The measurement results demonstrate that with an increase in the length of the grounding device, its diameter and the volume of the injected mixture, the resistance decreases. It is shown that the proposed solution makes it possible to reduce seasonality by 1.64–2.1 times, depending on the couplings used, and to obtain a grounding conductor with an equivalent diameter dozens of times larger than the diameter of a composite grounding conductor. The authors propose the use of soil-replacing mixtures to reduce soil resistivity and ensure the stability of the grounding loop throughout the entire service life. The proposed method of applying mixtures without pre-drilling makes it possible to reduce the cost of constructing grounding devices.

THE EFFECT OF CORROSION ON THE DYNAMIC BEHAVIOUR OF AISI 4140, AISI 4340, AND AISI 5140 STEELS EXPOSED TO 3.5 wt.% NaCl ENVIRONMENT

Material loss due to corrosion can weaken the structural integrity of systems and potentially lead to failure if timely action is not taken. Such deterioration adversely affects the dynamic behavior of metals. This study deals with the post-corrosion changes in the dynamic behavior of AISI 4140, AISI 4340 and AISI 5140 metals after exposure to 3.5 wt.% NaCl for 1, 7, 15 and 30 days. Electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (Dynamic-EIS) were used to elucidate the corrosion mechanisms. Modal analysis and finite element method (FEM) were used to characterise dynamic behavior changes. In addition, scanning electron microscopy (SEM-EDS) was used to analyse changes in surface morphology after corrosion. The results show a decrease in the corrosion resistance of AISI 4140, AISI 4340 and AISI 5140 metals over time, although there is an improvement after 30 days. The electrochemical test results indicated that the metal with the highest corrosion resistance in a 3.5 wt.% NaCl environment was 4340, while the lowest was 5140. In particular, the natural frequency values showed a decreasing trend with increasing corrosion exposure time, accompanied by discernible changes in mode shapes.

Stability Analysis of Jet Fuel-Bioethanol Blends: an Experimental Approach

Incorporating bioethanol into jet fuel blends has garnered increasing attention as a viable strategy to reduce dependence on fossil fuels and address environmental issues. This study investigates the influence of different amounts of bioethanol on the stability properties of jet fuel blends. Bioethanol addition to jet fuel causes a steady increase in its freezing point. The alteration has been attributed to the destabilizing effect caused by polar hydrogen bonds in bioethanol on the intermolecular forces. Oxidation stability analysis demonstrates a clear correlation between ethanol content and a swift decrease in pressure resistance. Although pure jet fuel is highly stable, mixes that include bioethanol show much lower stability. This decline highlights the reduced impact of bioethanol on fuel stability and oxidation processes. The simultaneous occurrence of gum formation emphasizes the need for careful formulation strategies to prevent stability problems and system complexities. Moreover, the complex influence of bioethanol on the temperature, stability, and oxidation properties of jet fuel blends highlights the importance of using accurate formulation methodologies to improve aviation fuels.

Performance of heat sink using graphene nanoplatelets-H2O nanofluids for electronic cooling applications

ABSTRACT This study proposes a novel solution for enhancement of the performance of electronic chips using a liquid channel heat sink with graphene nanoplatelets (GnP) dispersed in deionized (DI) water (H2O). The nanofluid was prepared using a two-step method with variations made in the vol% of GnP from 0.01% to 0.1%, with the addition of sodium deoxycholate (0.75 vol%) added as surfactant. The prepared nanofluids remained stable for two weeks without any sedimentation. The thermo-physical properties at the required temperature have been measured and reported in previously published literature. The nanofluid was passed along the microchannels of the heat sink, and its heat transfer performance was experimentally studied. The heat input to the bottom surface of the heat sink was varied from 60 W to 100 W in increments of 10 W while the variation in the nanofluid mass flow rate was from 0.6 to 2.2 mL/s. The results indicated a 66% decrease in the heat sink base temperature with 0.1 vol% of GnP/H2O nanofluid compared to H2O. The maximum decrease in thermal resistance observed was 58%. The convective heat transfer coefficient was enhanced by 23% higher at 0.1 vol% of GnP/H2O nanofluid compared to H2O.

Synthesis of ferrofluid using magnetite (Fe3O4), citric acid and deionized water and its characterizations for the application of a non-uniform magnetic thermosyphon

The performance improvement of a thermosyphon for disseminating heat is significant for the thermal management of a system. Furthermore, the water as the working liquid in a thermosyphon has an operating limit. Therefore, adding particles in the nanofluids as a working liquid could improve the thermal properties of thermosyphon and boiling temperature. Additionally, the effects of a non-uniform magnetic field on the ferrofluid thermosyphon at three locations: evaporator, adiabatic, and condenser were analysed. In this investigation, a two-step method was utilized, the ferrofluid was synthesized using magnetite (Fe3O4), citric acid, and deionized water. First, the Fe3O4 nanoparticles and associated ferrofluid were fully characterized from X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), magnetic properties analysis, zeta potential, and thermal properties, respectively. Then, the performance of thermosyphon heat pipes filled using high filling ratios of 70, 80, 90, and 100% of stable synthesized ferrofluid at 0.5wt% were examined. The results were compared to water using similar filling ratios that have been experimentally evaluated. The thermosyphon heat pipe (copper container) has a diameter of 12.7mm and a length of 200mm. The thermal performance test of the thermosyphon filled using the ferrofluid suggested a thermal resistance decrease from 1.95 to 1.20 °C/W with filling ratios of 70 to 90% of evaporator volume. The effective thermal conductivity of the thermosyphon is improved from 685 to 1160W/m°C at similar filling ratios. On the other hand, higher thermal resistance and lower effective thermal conductivity of thermosyphon filled using water were obtained at similar filling ratios of 70 to 90%. The values are 2.2 to 1.3 °C/W and 600 to 1000W/m°C, respectively. Moreover, the thermosyphon filled using the ferrofluid with a filling ratio of 90% and a non-uniform magnetic field (two sides) on the evaporator section has a thermal resistance and an effective thermal conductivity of 1.9 °C/W and 690W/m°C. The result has a lower thermal conductivity value compared to the thermosyphon filled with ferrofluid without a non-uniform magnetic field at a similar filling ratio of 90% of 1160W/m°C. This occurs due to less particle deposition on the inner surface of the thermosyphon as an effect of the magnetic field. A non-uniform magnetic field effect to the several sections of the thermosyphon (e.g., evaporator, adiabatic, and condenser) as the novelty of the research required to be modified to optimize the results.

Orthostatic blood pressure reactions and resting heart rate in relation to lung function - the Swedish CArdioPulmonary bioImage Study (SCAPIS)

BackgroundThere is a well-known comorbidity between chronic obstructive pulmonary disease (COPD) and coronary artery disease (CAD) which is only partially explained by common risk factors. Markers of cardiovascular autonomic dysfunction (CVAD), such as orthostatic hypotension and increased resting heart rate, are strongly associated with CAD. The autonomic nervous system also innervates the airways, and several studies have shown an association between autonomic dysfunction and COPD. However, less is known about whether CVAD and impairment of respiratory capacity are related in the population. We thus aimed to assess the relationship between markers of subtle CVAD and lung function in middle-aged subjects.MethodsIn this cross-sectional study, we analysed data from CVAD assessment (orthostatic blood pressure and heart rate measurements) and pulmonary function tests from 5886 individuals from the Swedish CArdioPulmonary bioImage Study (SCAPIS). Subjects were middle aged and randomly selected from the Swedish population. Linear regression models and ANOVA analyses were used to relate orthostatic blood pressure and resting heart rate to lung function parameters (forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC-ratio, diffusion capacity for carbon monoxide (DLCO), respiratory resistance at 5 Hz (R5), respiratory resistance at 20 Hz (R20), decrease in resistance from R5 to R20 (R5-R20), reactance in distal airways (X5), resonant frequency (Fres) and reactance area (AX)).ResultsIncreasing systolic orthostatic blood pressure, decreasing diastolic orthostatic blood pressure, and increased resting heart rate associated with lower FVC (all p < 0.001) and FEV1 (p = 0.001; p = 0.005; p < 0.001, respectively) in models including age, sex and height. Apart from diastolic orthostatic blood pressure and FEV1, all relationships remained significant after adjustment for possible confounders. Increased resting heart rate was associated with reduced DLCO (p < 0.001).ConclusionsIncreasing systolic orthostatic blood pressure, decreasing diastolic orthostatic blood pressure, and increased resting heart rate are associated with lower lung function, after adjustments for age, sex and height. These finding indicates associations between signs of cardiovascular autonomic dysfunction and lower lung function in the general population. However, the observed differences in lung function were small and the clinical application is unclear.

High temperature properties of nichrome resistant heaters – A systematic comparison of APS, suspension and filament HVOF sprayed coatings

This study investigates the performance of Nichrome coatings, a nickel‑chromium alloy containing 20 wt.-% chromium, applied using three thermal spray techniques: powder plasma spray, suspension HVOF, and filament HVOF. Thin, homogeneous coatings approximately 35 μm thick were deposited onto steel substrates pre-coated with an insulating Al2O3 layer. The oxide content in the coatings varied based on the spraying technique and parameters, ranging from 57 to 64 vol.-% for plasma spraying, 42 to 54 vol.-% for filament HVOF, and 9 to 43 vol.-% for suspension HVOF. The coating's heating performance was evaluated over a temperature range of room temperature (RT) to 700 °C. Analytical techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) were employed to investigate the mechanisms affecting temperature-dependent resistivity in relation to the coating microstructure. The results indicate that increased oxidation leads to a decrease in specific resistivity at RT (ρ0). In example, plasma sprayed coatings exhibited lower specific resistivity ρ0 of 0.80 Ωmm2/m. In contrast, suspension HVOF reaches values up to 2.75 Ωmm2/m. At the same time coatings with higher oxidation levels demonstrate an elevated dependence of resistivity as compared to less oxidized coatings. Both can be attributed to changes in the phase composition of the conductive phase as the dominating factor, primarily driven by the preferential oxidation of chromium during the spraying process. Notably, the results provide valuable information for adjusting the coating properties to suit specific needs, such as self-regulating or high-temperature heating applications.

Physical properties and thermal stability of zirconium platinum nitride thin films

Ternary transition metal nitrides (TMNs) promise to significantly expand the material design space by opening new functionality and enhancing existing properties. However, most systems have only been investigated computationally, and limited understanding of their stabilizing mechanisms restricts translation to experimental synthesis. To better elucidate key factors in designing ternary TMNs, we experimentally fabricate and analyze the physical properties of the ternary Zr–Pt–N system. Structural analysis and density functional theory modeling demonstrate that Pt substitutes nitrogen on the nonmetallic sublattice, which destabilizes the rock salt structure and forms a complex cubic phase. We also show insolubility of Pt in the Zr–Pt–N at 45 at. % with the formation of a secondary Pt-rich phase. The measured reduced plasma frequency, decrease in resistivity, and decrease in hardness reflect a dominance of metallic behavior in bonding. Additionally, we observe the exsolution of Pt nano precipitates from the Zr–Pt–N films upon annealing as well as degradation in the nitridic film's thermal stability. Even at low concentrations (1%), Pt facilitates a solid reaction with the Si substrate that is otherwise inaccessible in ZrN films.

Effect of freezing–thawing cycles and high temperatures on concretes containing partial replacement of fine grain blast and Electric Arc Furnace slags

This study examines the effects of local industrial by-products, such as iron slag and steel slag, as partial replacements of fine grain at 10%, 15%, and 25%, individually and combined. The research evaluates the impact on mechanical resistance under freeze–thaw cycles and high temperatures. Additionally, the study explores the effects of incorporating 0.3% polypropylene fibers by volume and 10% microsilica by cement weight (500 kg/m3). The durability of concrete samples exposed to freezing–thawing at the age of 28 days with 100 cycles and at temperatures of 400 °C and 800 °C at the age of 90 days in the gas furnace were investigated in terms of compressive strength. Samples subjected to 100 freeze–thaw cycles showed increased porosity and expansion of microcracks, leading to a loosened macrostructure and a 0.8% decrease in weight. Findings indicate that the partial replacement of slag in the fine grain and combining these materials with polypropylene and microsilica fibers improved mechanical properties like compressive strength. Additionally, the freeze–thaw cycle caused a 32.46% decrease in sample resistance compared to the control state. Moreover, incorporating 10% slag enhanced the mechanical properties of samples at 400 °C and 800 °C, with a lower resistance loss when compared to designs without additives. The inclusion of 10% microsilica and 0.3% polypropylene fibers, however, reduced sample resistance at 800 °C compared to 400 °C. Microstructural analysis of GGBS in concrete using Scanning Electron Microscopy (SEM) revealed that the addition of GGBS produces a denser matrix populated with more angular particles, resulting in improved bonding properties compared to plain concrete.

Bacteriological Profile and Antimicrobial Resistance Patterns in Pediatric Urinary Tract Infections: A Cross-Sectional Study at Dhaka Shishu Hospital

Urinary tract infections (UTIs) are a prevalent concern in pediatric healthcare, causing distress to children, raising parental concerns, and potentially leading to lasting kidney damage. The highest incidence of first-time symptomatic UTIs occurs in infants during the first year of life, with a subsequent marked decrease. Febrile infants under 2 months, presenting with unexplained fever, constitute a critical subset requiring particular attention. Knowledge of the bacteriological profile and antimicrobial resistance patterns in specific regions is crucial for guiding effective treatment strategies. Methods: A cross-sectional study was conducted at 250 Bedded General Hospital, Jamalpur, Bangladesh from Feb 2016 to Aug 2016 to assess the bacteriological profile and antibiotic resistance patterns in pediatric UTIs. A total of 147 culture-positive UTI patients were included. Bacterial isolates were identified, and colony counts for samples with ≥105 CFU/mL bacteria were considered positive. Antimicrobial susceptibility testing was performed using twelve agents, and resistance patterns were analyzed. Results: Among the 147 culture-positive UTI patients, Escherichia coli (E-coli) was the predominant isolate (70%), followed by Klebsiella spp. (13.6%), Pseudomonas (5.44%), Enterobacter spp (3.40%), Staphylococcus Aureus (3.40%), Proteus (2.72%), and Enterococcus (1.36%). Antimicrobial resistance analysis revealed varying patterns, with Cefradine (79.59%), Co-trimoxazole (SXT) (69.39%), Nalidixic acid (NA) (66.67%), and Ceftazidime (CTM) (48.98%) showing higher resistance rates. No drug exhibited 100% resistance against urinary pathogens, indicating a dynamic resistance landscape. Conclusion: This study highlights the importance of understanding local prevalence and resistance patterns in guiding empirical antibiotic selection for pediatric UTIs. The observed decrease in antimicrobial resistance underscores the need for continuous surveillance and tailored antibiotic strategies. Clinicians should base their treatment decisions on the specific epidemiological context rather than relying solely on universal or national guidelines.

Interface structure of PN junctions in NiO–WO3–FTO photoelectrode for efficient DSSCs and enhanced photoresponses

In the current global energy crisis, dye-sensitized solar cells (DSSCs) with excellent performance and loaded with P/N type semiconductor heterojunctions (PN junctions) has attracted huge attention in renewable energy research. This study reports the unique energy level structure and synergistic effect of the PN junction interfaces in response to light. Photoelectrodes containing NiO–WO3 nano-powder (NPs) layers were synthesized on fluorine-doped tin oxide (FTO) substrates by a simple method, which can respond to full-spectrum absorption of sunlight. In this study, the carrier densities in the P-type and N-type semiconductor heterojunctions at a light intensity of 2 SUN (2000 W/m2) were 1.38 × 1028 m−3 and 4.27 × 1028 m−3, respectively. These values are 2.7 and 1.9 times higher than those in dark conditions, indicating that the electrode excels in converting light into electrical energy, outperforming other reported results. Although PN junctions are often used in applications such as DSSCs and energy storage devices, the photoresponses of the heterojunction energy band structure still need to be elucidated. In this work, the analysis of the charge depletion region width revealed the electron transfer mechanism during the charge and discharge process under light illumination. Additionally, the electrochemical experiment demonstrated the impact of space charge at the interface on the energy levels. Furthermore, by studying the energy level structure of the PN junction, it was confirmed that the internal resistance decreases and the photocurrent increases under light conditions. The design and application flexibility of the PN junctions were verified based on these results and the possible applications of this photoelectrode in solar cells were elucidated.

Preparation of ester-modified nano-SiO2/silicate coatings and its application in the impermeability of concrete

Surface treatment protective technology is a cost-effective approach to prevent harmful ions from infiltrating concrete, avoiding the deterioration of performance and increasing longevity. Here, a novel coupling agent with ester group (MA-KH-550) is synthesized from γ-aminopropyltriethoxysilane (KH-550) and methyl acrylate (MA) to modify nano-SiO2 particles. Subsequently, the ester-modified nano-SiO2 can be successfully dispersed in alkaline composite silicate solutions to fabricate nano-SiO2/silicate coatings, improving the impermeability of concrete. The incorporation of nano-SiO2 particles can fill microscopic pores in cementitious materials, which improves the compactness of the concrete. Furthermore, nano-SiO2 particles can also accelerate secondary hydration of cement and synergistically generate more calcium silicate hydrate gel with silicates to further boost the compactness of the concrete. High-compactness coatings reduce the penetration of the medium, thereby enhancing the impermeability performance of the concrete. When the nano-SiO2 particle content is 1.0 wt%, the optimal performance of concrete is achieved. Compared with the original C30 concrete, the C30 concrete treated with the nano-SiO2/composite silicate (nano-SiO2/CSC) shows a 31.1 % decrease in chloride ion resistance, a 35.5 % reduction in carbonization resistance, a loss rate of 1.08 % for anti-freezing quality. This work charts a new course for designing and developing high-performance composite silicate coatings for concrete.

Inducible and reversible SOD2 knockdown in mouse skeletal muscle drives impaired pyruvate oxidation and reduced metabolic flexibility

IntroductionSkeletal muscle mitochondrial dysfunction is a key characteristic of aging muscle and contributes to age related diseases such as sarcopenia, frailty, and type 2 diabetes. Mitochondrial oxidative stress has been implicated as a driving factor in these age-related diseases, however whether it is a cause, or a consequence of mitochondrial dysfunction remains to be determined. The development of flexible genetic models is an important tool to test the mechanistic role of mitochondrial oxidative stress on skeletal muscle metabolic dysfunction. We characterize a new model of inducible and reversible mitochondrial redox stress using a tetracycline controlled skeletal muscle specific short hairpin RNA targeted to superoxide dismutase 2 (iSOD2).Methods: iSOD2 KD and control (CON) animals were administered doxycycline for 3- or 12- weeks and followed for up to 24 weeks and mitochondrial respiration and muscle contraction were measured to define the time course of SOD2 KD and muscle functional changes and recovery. ResultsMaximum knockdown of SOD2 protein occurred by 6 weeks and recovered by 24 weeks after DOX treatment. Mitochondrial aconitase activity and maximum mitochondrial respiration declined in KD muscle by 12 weeks and recovered by 24 weeks. There were no significant differences in antioxidant or mitochondrial biogenesis genes between groups. Twelve-week KD showed a small, but significant decrease in muscle fatigue resistance. The primary phenotype was reduced metabolic flexibility characterized by impaired pyruvate driven respiration when other substrates are present. The pyruvate dehydrogenase kinase inhibitor dichloroacetate partially restored pyruvate driven respiration, while the thiol reductant DTT did not. ConclusionWe use a model of inducible and reversible skeletal muscle SOD2 knockdown to demonstrate that elevated matrix superoxide reversibly impairs mitochondrial substrate flexibility characterized by impaired pyruvate oxidation. Despite the bioenergetic effect, the limited change in gene expression suggests that the elevated redox stress in this model is confined to the mitochondrial matrix.

Large photoresistance and photoinduced magnetoresistance in La0.67Ca0.33MnO3 thin film on silicon substrate

Abstract The effects of light illumination and magnetic field on the electrical transport properties of La0.67Ca0.33MnO3 thin film on a silicon substrate have been studied in detail. Large value of colossal magnetoresistance has been observed under an applied magnetic field in the whole temperature range below 150 K which is related to the presence of both antiferromagnetic and ferromagnetic phase in the sample. A significant amount of resistance drop is caused by light illumination even at extremely low light intensities, ∼−22% with light of 0.3 μW cm−2 intensity and ∼−42% with 6.2 μW cm−2 intensity at 600 nm wavelength. There has been a notable rise in the photoinduced magnetoresistance value, specifically, a significant decrease in resistance occurs in simultaneous presence of magnetic field and light. For 1 T applied magnetic field, MR% rises from −33% in dark to −58% under light illumination at 150 K i.e. ΔMR% is 25%. As the strength of the magnetic field increases, ΔMR% decreases, suggesting that the magnetoresistive photoinduced phenomenon is more pronounced in the presence of mix phases in the sample. This combined enhanced magnetoresistive photoinduced phenomenon is explained by the interaction of photogenerated charge carriers in the sample and applied magnetic field.

Sequential irradiation does not improve fatigue crack propagation resistance of human cortical bone at 15 kGy

Sequential irradiation has been advocated for mitigating the reduction in fatigue properties of tendon compared to a single dose. However, to our knowledge, its capability of mitigating fatigue losses in bone is unknown. Recently, we reported that sequential irradiation did not mitigate losses in high-cycle S-N fatigue life of cortical bone at 15 kGy; however, it is unclear if sequential irradiation provides a benefit to fatigue crack propagation resistance. Our previous study also showed that radiation-induced collagen chain fragmentation and crosslinking increased from 0 to 15 kGy, suggesting that both likely contribute to the reduction in high-cycle S-N fatigue life within this dose range. Our objectives were: 1) to evaluate the fatigue crack propagation resistance of cortical bone and the effect of radiation on fracture plane damage zone thickness (DZT) at the crack tip in the dose range of 0–15 kGy, and 2) to evaluate whether sequential irradiation at 15 kGy mitigates the loss of fatigue crack propagation resistance of cortical bone compared to a single irradiation dose. Compact tension specimens from four male donor femoral pairs (ages 21–61 years old) were divided into 5 treatment groups (0 kGy, 5 kGy, 10 kGy, 15 kGy, and a 15 kGy sequential irradiation dose of 5 kGy sequentially irradiated with 10 kGy) and subjected to fatigue crack propagation testing (n = 3–4 specimens per group) where fatigue crack growth rate da/dN and cyclic stress intensity factor ΔK were determined. Following testing, specimens were bulk stained in basic fuchsin, embedded in poly(methylmethacrylate), sectioned, and mounted on acrylic slides to evaluate fracture plane DZT at known crack lengths. Sections were then imaged with a fluorescence microscope, and fracture plane DZT was measured using ImageJ (n = 3–4 specimens per group) and analyzed as a function of ΔK. We observed a decrease in fatigue crack propagation resistance at 15 kGy compared to doses of 10 kGy or lower (p ≤ 0.013). Fracture plane DZT decreased overall with increasing radiation dose from 0 to 15 kGy. Sequential irradiation offered no improvement in fatigue crack propagation resistance (p = 0.98). Radiation-induced collagen chain fragmentation and crosslinking in this dose range likely contribute to a decrease in energy dissipation capability with increasing radiation dose. Other alternative radiation sterilization methods besides sequential irradiation may be warranted to mitigate radiation-induced tissue damage and extend the functional lifetime of structural cortical bone allografts.

Features of management of patients with seasonal allergic rhinitis

Introduction. Seasonal allergic rhinitis continues to be one of the most common chronic diseases, affecting up to 24% of the adult population of the Russian Federation.Aim. To evaluate the effectiveness of the drug mometasone furoate (Nozefrin Allergy) in patients with seasonal allergic rhinitis in outpatient practice.Materials and methods. The study was conducted in a group of 42 patients aged 18 to 73 years (average age 39.0 ± 15.5 years) diagnosed with seasonal allergic rhinitis. All patients received monotherapy with Nozefrin Allergy, 2 injections (50 mcg of mometasone furoate each) into each nostril once a day for 30 days. The effectiveness of the treatment was determined on the 7th, 14th, 30th day of treatment and on the 60th day.Results and discussion. During the use of the drug Nozefrin Allergy, by the 7th day there was a significant decrease in complaints of impaired smell by 3.6 times, sneezing by 2.4 times, discharge from the nasal cavity decreased by 2.3 times, and nasal congestion by 2.3 times. 2.1 times. After 14 days, nasal congestion disappeared in 64.3%, nasal discharge and itching in the nasal cavity were absent in 69.0% and 88.1% of patients. According to the SST-12 test, already by the 7th day of using the drug Nozefrin Allergy, there was an increase in the average total score to 10.1 ± 1.9 points, which corresponds to normosmia. At days 14, 30, and 60, the mean total SST-12 score remained stable at 10.6 ± 0.9 points, 10.9 ± 1.1 points, and 11.1 ± 0.5 points, respectively. The dynamics of respiratory function at the end of the course of treatment was characterized by an improvementin the total volumetric flow to 783.4 ± 162.7 cm3/s and a decrease in nasal resistance to 0.2 ± 0.1 cPa/ml. The total rTNSS scale score by the 7th day decreased to 9.1 ± 0.4 points, the severity of the assessed complaints was moderate.Conclusion. The data obtained indicate the effectiveness of using the drug Nozefrin Allergy in patients with seasonal allergic rhinitis in outpatient clinical practice.

Electrochemical investigations of decorated graphite felt electrodes with Nafion/TiO2 nanoparticles for vanadium redox flow battery: Improving electro-catalytic characteristics

The present study aimed to investigate the effect of Nafion/TiO2 nanoparticles as an electrocatalyst on the electrochemical behavior of graphite felt (GF) electrodes in a vanadium redox flow battery. Various electrochemical tests, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV), were conducted to assess the performance of these electrodes at different concentrations of nanoparticles (2–4 g l-1). Additionally, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy were employed to analyze the chemical composition, bonding, and morphology of the decorated electrodes, respectively. The CV results revealed several effects of TiO2 nanoparticles on the GF electrode, such as increased peak intensity and shifted peak sites. As the concentration of nanoparticles increased, the peak intensity rose by up to 44%. Moreover, the potentials of the decorated electrodes shifted towards the favorable side compared to the GF electrode, with changes ranging from 18 to 84%. Overall, the optimal concentration of TiO2 nanoparticles (3 g l-1) exhibited excellent electrode performance, characterized by the highest calculated diffusion coefficient, greater reversibility, enhanced electron transfer kinetics, improved stability, lower over-potential, and the lowest activation energy for redox reactions. EIS results demonstrated a significant decrease in polarization resistance (67.2–70.8%) for the decorated electrodes. Furthermore, LSV measurements indicated that the utilization of nano-electrocatalysts effectively inhibited hydrogen evolution at negative potentials.