Increase In Diameter Research Articles

The Fiber Cell-Specific Overexpression of COMT2 Modulates Secondary Cell Wall Biosynthesis in Poplar

Wood, as a natural and renewable resource, plays a crucial role in industrial production and daily life. Lignin, as one of the three major components of the plant cell secondary wall, plays a key role in conferring mechanical strength and enhancing stress resistance. The caffeic acid-O-methyltransferase (COMT) family of oxygen-methyltransferases is a core regulatory node in the downstream pathway of lignin biosynthesis. Here, our report shows that caffeic acid-O-methyltransferase 2 (COMT2) exhibits high conservation across several species. Tissue expression analysis reveals that COMT2 is specifically highly expressed in the secondary xylem of Populus tomentosa stems. We demonstrated that the specific overexpression of COMT2 in fiber cells of Populus tomentosa led to a significant increase in plant height, stem diameter, internode number, and stem dry weight. Furthermore, we found that the specific overexpression of COMT2 in fiber cells promotes xylem differentiation, lignin accumulation, and the thickening of the secondary cell wall (SCW) in fiber cells. Our results indicate that key downstream lignin biosynthesis enzyme genes are upregulated in transgenic plants. Additionally, mechanical properties of stem bending resistance, puncture resistance, and compressive strength in the transgenic lines are significantly improved. Moreover, we further created the DUFpro:COMT2 transgenic lines of Populus deltoides × Populus. euramericana cv ‘Nanlin895’ to verify the functional conservation of COMT2 in closely related poplar species. The DUFpro:COMT2 Populus deltoides × Populus. euramericana cv ‘Nanlin895’ transgenic lines exhibited phenotypes similar to those observed in the P. tomentosa transgenic plants, which showed enhanced growth, increased lignin accumulation, and greater wood strength. Overall, the specific overexpression of the caffeic acid O-methyltransferase gene COMT2 in poplar stem fiber cells has enhanced the wood biomass, wood properties, and mechanical strength of poplar stems.

Hydrogen-rich water enhances vegetable growth and fruit quality by regulating ascorbate biosynthesis.

Hydrogen-rich water enhances vegetable growth and fruit quality by regulating ascorbate biosynthesis.

Effect of tourniquet time and nerve diameter change on nerve damage in upper extremity surgery interventions.

Effect of tourniquet time and nerve diameter change on nerve damage in upper extremity surgery interventions.

Simulating the effects of climate change on the growth and management of uneven-aged Oriental beech (Fagus orientalis L.) in Hyrcanian forests of Iran

Abstract Adaptive management approaches are needed to maintain and improve forests’ resilience to future climatic changes. Climate sensitive forest increment models are the crucial tools to evaluate the performance of the adaptive strategies in forest management under climate change. Oriental beech (Fagus orientalis L.) is the most dominating and commercially important tree species in Hyrcanian forests of Iran, the main source of timber production, biodiversity conservation, and eco-tourism. Consequently, this study aims to achieve three primary objectives: (1) to develop a climate-sensitive tree increment and yield model for oriental beech forests (2) to predict the increment and yielding of these forests in the future under climate change (IPCC scenarios), and (3) to analyze the resilience of four alternative management strategies including business as usual (BAU) and logging ban. We re-calibrated a single-tree diameter and height increment, and tree survival models using forest measurement data from permanent plots with five-year interval and from 1988 to 2018. By validating the models, three climate change scenarios RCP2.6, RCP4.5 and RCP8.5 as well as four harvest strategies (logging ban, intensified logging (50% above BAU), and decreased logging (50% < BAU), and BAU) were applied for the simulation of increment and survival probability of single trees in a selected site. Our findings indicate that climate change, particularly increased drought stress under the RCP8.5 scenario, significantly reduces the increment and survival probability of beech trees. However, under RCP2.6 and RCP4.5, we observed a slight increase in increment. Implementing a logging ban as a management strategy emerged as the most resilient alternative for these forests, potentially fostering an increase in both diameter (up to 5.93 cm) and height increment (up to 3.12 m) until the final period. These findings lend support to the existing forest policy of enforcing a ten-year logging ban in the Hyrcanian forests of Iran.

Mesiodistal and buccolingual crown diameters of permanent teeth

BackgroundThis study aimed to determine normative values for mesiodistal and buccolingual crown diameters of permanent teeth in the Turkish population and compare them with values reported in previous studies for other populations and the Turkish population.Materials and methodsThe mesiodistal and buccolingual diameters of permanent teeth were measured using digital calipers from dental cast models of 200 patients. The data analysis was conducted employing the SPSS 21 package software. The descriptive statistics were obtained for all parameters. Student t-test was utilized to compare the measurements between male and female patients. A paired t-test was used to compare the right and left side teeth. The significance level was set at 0.05.ResultsA total of 4800 teeth were measured. Men’s tooth sizes were larger than women’s tooth sizes. A stronger sexual dimorphism was observed in the buccolingual diameter in comparison to the mesiodistal diameter. No clinically significant differences were observed between antimeric teeth. In the maxilla and mandible, the first molars were found to have the largest mesiodistal and buccolingual diameters, whereas mandibular central teeth had the smallest diameters.ConclusionsCurrent norm values of mesiodistal and buccolingual diameters of permanent teeth in the Turkish population were established. The norm values presented are close to the tooth dimensions in studies carried out on other populations. Compared to previous studies, there is an increase in mesiodistal diameters in the Turkish population, with this increase being more pronounced in males. The mean mesiodistal and buccolingual diameters of permanent teeth can be useful for orthodontists, prosthodontists, anatomists, anthropologists, and forensic dentistry specialists.

Technology of preparation of sleeve ends before pilgrims rolling

The paper considers the issues of improvement of hot pilgrim rolling of pipes by means of preparation of front and rear ends of sleeves. The presence of a gap between the sleeve and mandrel increases transverse variance and reduces pipe accuracy during pilgrim rolling. In the present article the issues of preparation of the front and rear ends of the sleeves to ensure the alignment of the sleeve and mandrel in the process of Pilgrim rolling are comprehensively considered. The preparation of the front ends of the sleeves is proposed to be carried out on a slant-rolling piercing mill by idle rollers of the swaging device located on the output side of the piercing mill. In the work a new technology of preparation of front ends of sleeves providing their reduction by idle rollers without compression along the thickness of the sleeve wall is proposed. The concept of a running-in device characterised by lower metal intensity and, accordingly, capital expenditures is proposed. By means of the sliding line method the forces acting on the idle rollers during reduction of the front ends of the sleeves are determined. The questions of preparation of back ends of sleeves before pilgrim rolling of pipes are considered. The back end of the sleeve after piercing has reduced outer and inner diameters, which makes it difficult to charge the mandrel into the sleeve, increasing the gap between them, which adversely affects the deformation of metal by rolls during pilgrim rolling, increasing the differentiality of pipes. To facilitate loading of the mandrel into the sleeve, the piercing technology is used with the mandrel moving in the direction opposite to the sleeve movement when the rear end of the workpiece approaches the rolls. As a result, it is possible to provide thinning of the sleeve wall in the direction towards its rear end with an increase in the internal diameter at the rear end, which facilitates the conditions of mandrel loading into the sleeve. Thinning of the wall of the rear end of the sleeve due to the convergence of the rolls of the piercing mill can reduce the volume and mass of the separated pilgrim head. To facilitate the loading of the mandrel into the sleeve with the prepared front end at the out-of-station charging section of the piercing mill, the calibration of the front end of the mandrel with a cylindrical shape is proposed, while ensuring the minimum tension between the front end of the sleeve and the mandrel for centring between them. The proposed technology of centring the rear end of the sleeve on the mandrel, which provides for the presence of a conical belt adjacent to the head of the mandrel. The parameters of the conical belt of the mandrel are determined taking into account the gap between the mandrel and the sleeve with its constant value along the length of the sleeve. Charging of the mandrel with a new calibration of the front end and a conical belt adjacent to the head with the help of a hydraulic cylinder of the priming press at the section of off-stage charging ensures centring of the front and rear ends of the sleeve on the mandrel.

Changes in Pore Structure and Gas Adsorption–Desorption Characteristics of Coal Under High-Voltage Electric Pulses

High-voltage electrical pulses (HVEPs), a new technology designed to enhance the permeability of coal seams, have received significant attention for their application in gas extraction from low-permeability coal seams. This study designed a high-pressure adjustable electrical pulse experimental system to investigate the effects of HVEPs on the pore structure and gas adsorption–desorption characteristics of bituminous coal samples. The results revealed that HVEPs effectively restructured pore morphology in coal samples through the opening of previously sealed and partially enclosed pores. This led to a significant increase in the average pore diameter, total pore volume, and porosity. However, the increase in total specific surface area was minimal. Moreover, the connectivity of pores was continuously enhanced. As the discharge voltage increased, the pore structure significantly improved. However, HVEP treatment slightly increased the adsorption pores (micropores and transition pores) and significantly increased the seepage pores (mesopores and macropores), which facilitated the free flow of gas within the coal samples. Additionally, HVEP treatment significantly reduced both the adsorption rate and the maximum gas adsorption capacity of the coal samples, indicating a strong inhibitory effect of HVEPs on gas adsorption. Conversely, HVEPs significantly increased the gas desorption capacity and desorption rate, suggesting that HVEPs facilitated the rapid desorption and release of gas from the coal samples. Furthermore, HVEP treatment increased the gas diffusion coefficient of the coal samples, which reduced their resistance to free diffusion after desorption and promoted gas extraction from the coal seam.

Study on the Movement and Distribution Patterns of Sand Particles in a Vane-Type Multiphase Pump

In oilfield operations, produced fluids consist of complex mixtures including heavy oil, sand, and water. Variations in sand particle parameters and operational conditions can significantly impact the performance of multiphase pumps. To elucidate the movement patterns of sand particles within a vane-type multiphase pump, this study employs the Discrete Phase Model (DPM) to investigate the effects of different sand particle parameters and operational conditions on the internal flow characteristics. The study found that: sand particle diameter, flow rate, rotational speed, and oil content significantly influence the trajectories of the solid–liquid two-phase flow, the motion characteristics of sand particles, and the vortices in the liquid flow field. As sand particle diameter increases, their radial and axial momentum first rise and then decline. Both radial and axial momentum are positively correlated with sand concentration. An increase in flow rate, higher rotational speed, and lower oil content all lead to greater fluctuations in the radial momentum curve of sand particles inside the impeller. Larger sand particles are predominantly distributed near the inlet, while smaller particles are more concentrated at the outlet. Higher sand concentrations and non-spherical particles increase particle distribution within the flow passages, with the guide vane channels exhibiting the most pronounced accumulation—reaching a maximum concentration of 6260 kg/m3 due to elevated sand loading. Increasing flow rate, rotational speed, or oil content significantly reduces sand concentration in the flow channel, promoting more efficient particle transport. Conversely, lower inlet sand concentration, non-spherical particles, reduced flow rate, decreased rotational speed, and higher oil content all result in fewer large particles in the flow passage. The findings provide important guidance for improving the wear resistance of vane-type multiphase pumps.

Deceleration of polymer translocation through a nanopore via polymer brushes.

This work employs Brownian dynamics simulations to study the deceleration of polymer translocation through grafting nanopores. The study found that both grafting density and length positively correlate with the translocation time. The translocation time increases slowly when the grafted chains have not yet formed a blocking layer. However, the translocation time increases rapidly once a blocking layer is formed. Additionally, dual-side grafting exhibits a stronger regulatory effect on polymer translocation than cis-side and trans-side grafting. Notably, the increase in nanopore diameter weakens the regulatory effect of the grafted chains on polymer translocation. Furthermore, when passing through a bare nanopore, the polymer undergoes three stages of motion: acceleration, deceleration, and re-acceleration. The presence of grafted chains reduces the translocation speed, making the polymer's motion in the second stage closer to uniform motion. This study provides new insights into using grafted chains to slow down polymer translocation in nanopores.

Molecular Interactions and Spectral Changes of Beta-and Gamma-Irradiated Silicon Clusters with different Time Intervals

Silicon clusters have garnered significant interest due to their unique physical and chemical properties, which make them valuable in fields such as nanotechnology, optoelectronics, and materials science. The purpose of this research is to investigate the effects of beta and gamma irradiation on silicon clusters, with a particular emphasis on gaining a knowledge of how irradiation over varying time intervals contributes to the molecular interactions and spectral features of silicon clusters. The ambient pressure and the two-step acid-base catalysis were both reliant on the manufacturing process. Beta and gamma radiation were used as sources at 2, 4, and 6 hours. The work combines spectroscopic analysis with molecular interaction assessments, and it makes use of FTIR analysis, N2 adsorption-desorption, FESEM, and EDS in order to shed light on the behavior of silicon before and after it has been irradiated in varied concentration clusters across time. Based on the findings, it was determined that the samples that were subjected to gamma radiation did not exhibit any discernible changes in their chemical structure, pore structure, or even surface appearance. Beta irradiation was applied to the samples for a period of six hours, and after that, there was a small alteration in the pore structure of the sample, the surface area decreases from 851.02 before irradiation to 833.03 at Beta Rad. This decrease occurred due to gamma radiation. The reduction was minimal. After irradiation, the pore size decreases from 10.44 to 0.9 and 0.8, while the pore volume, particle size, and pore diameter increase. The FE-SEM images show morphological stability; indicates that its unique porous nanostructure remains largely unaffected under radiative stress. The study comes to the conclusion that silica aerogel is a material that has the potential to be used in radiation isolation.

Variation in Douglas-fir (Pseudotsuga menziesii var. menziesii) and red alder (Alnus rubra) stem taper across varying stand conditions in the Pacific Northwest

Tree taper has been of interest for over a century, yet questions remain regarding the effects of stand conditions created by silvicultural treatments and forest health on recoverable volume. This work utilizes data from Douglas-fir (Pseudotsuga menziesii (Mirb.)) (n=608) and red alder (Alnus rubra (Bong.)) (n=495) trees to assess the influences of fertilization, pruning, thinning, regeneration origin, and defoliation caused by Swiss Needle Cast (SNC; Nothophaeocryptopus gaeumannii), on stem taper in the Pacific Northwest. The Kozak (2004; For. Chor. 80: 507-515) variable-exponent equation was used to test the addition of treatment and crown variables as the model is widely regarded for its flexibility in application. Using a mixed effects framework, results reveal that thinning of Douglas-fir can result in a 3.5% increase in upper stem diameter inside bark, while pruning may lead to a 4.1% decrease. SNC-induced defoliation of Douglas-fir reduced mean diameter above-breast height by 11.5%. Total volume of naturally regenerated red alder was 16% greater than planted stems. Overall, thinning of healthy Douglas-fir and planting red alder may increase recoverable volume and C captured in long-term timber products in the region, and that the inclusion of crown variables can increase the predictive power of taper for some species.

Application of Diverse Nutrients (N, P, and K) Throughout the Annual Growth Cycle Influences the Phenology and Biomass of Paeonia ostii

The tree peony holds significant historical, cultural, and practical value. P. ostii is extensively cultivated in China, where it represents the primary oil-producing variety of tree peonies. However, the current nutrient supplementation system for P. ostii lacks an empirical basis, resulting in frequent wastage of nutrients during daily production. In this study, varying ratios and quantities of nitrogen, phosphorus, and potassium were administered to P. ostii at distinct phases of its annual growth cycle, specifically during the bud sprouting, post-flowering, and dormancy periods. The results showed that during the bud sprouting period, the plants treated with a high nitrogen and potassium ratio (a high N&K ratio, N–P–K = 35%–20%–35%) had better flowering traits than those treated with a high phosphorus ratio (a high P ratio, N–P–K = 20%–35%–20%). Under the standard application amount, plants treated with a high N&K ratio outperformed those treated with a high P ratio in terms of flowering duration, net photosynthetic rate, and flowering biomass, with increases of 20.9%, 10.7%, and 32.9%, respectively. During the post-flowering period, all plants died when treated with 1.5 × standard amounts of the above ratios. At this period, the all-high ratio with N–P–K = 45%–45%–45% resulted in a 70.4% increase in fruit set, a 43.8% increase in seed number, and a 153.8% increase in biomass compared with the high N&K ratio. During the dormancy period, nutrient supplementation with the standard amount of P led to higher increases in ground diameter and biomass. Therefore, in subsequent tree peony production, particular attention should be paid to nutrient supplementation during the post-flowering period to prevent excessive fertilizer application and safeguard the plants’ normal growth and development.

Unraveling the site-specific features in small intestinal stromal tumors: a retrospective study

BackgroundGastrointestinal stromal tumors (GISTs) are a rare and less well-characterized disease. There is limited information on the clinical features of small intestinal GISTs at different sites.AimsTo enhance the understanding of the clinical characteristics and disease behavior of small intestinal GISTs based on their sites.MethodsWe conducted a retrospective review of medical records for 317 patients diagnosed with primary small intestinal GISTs confirmed by surgical pathology, comparing their clinical features and tumor characteristics.ResultsAccording to this cohort’s data, duodenal GISTs presented with longer disease durations and higher prevalence of melena (44.6%), while jejunal GISTs manifested as abdominal masses (11.5%) and acute gastrointestinal bleeding (GIB) (13.3%), with the highest rate of emergency surgeries (16.8%). Ileal GISTs were associated with an older age of onset and a higher prevalence of hematochezia (19.6%), with one-third of cases discovered incidentally during gynecological procedures. Notably, the biological behavior of small intestinal GISTs varied significantly by sites. Tumors demonstrated different immunochemical markers and a progressive increase in diameter, mitotic activity, T and M stages, and risk classification from the duodenum to the jejunum and ileum. These findings warrant further validation in prospective multicenter studies.ConclusionsSmall intestinal GISTs might exhibit distinct clinical presentations and oncological features depending on their sites.Visual abstract

PagKNAT5a Promotes Plant Growth by Enhancing Xylem Cell Elongation and Secondary Wall Formation in Poplar

Abstract Investigating the regulatory mechanisms that govern plant growth is crucial for developing high-yield wood varieties. In this context, the KNOX gene family has been identified as a significant regulator of plant growth. Our study focuses on PagKNAT5a, a class II member of the KNOX gene family, which has been found to promote the growth of poplar. Transgenic plants overexpressing PagKNAT5a exhibited significant increases in both plant height and stem diameter compared to wild-type controls. Histochemical analyses revealed that these overexpression lines had elongated xylem vessels and fiber cells, which correlated with elevated auxin levels. Additionally, we observed thickened secondary cell walls and increased lignin content in the fiber cells of these transgenic lines. Further protein interaction assays indicated that PagKNAT5a physically interacts with MYB46, a crucial regulator of secondary cell wall biosynthesis. This interaction activates downstream MYB-responsive elements (SMREs), leading to the upregulation of lignin biosynthesis genes driven by these cis-acting elements. Moreover, the increased photosynthetic rate observed in the overexpression lines is likely to significantly support overall plant development. Our findings suggest that PagKNAT5a facilitates the longitudinal elongation of vascular cells by modulating auxin levels, while simultaneously promoting the radial growth of xylem tissue through the activation of the MYB46-mediated lignin biosynthesis pathway. The functional analysis of PagKNAT5a highlights its potential for improving wood yield in forestry applications.

Measurement report: Size-resolved particle effective density measured by an AAC-SMPS and implications for chemical composition

Abstract. The effective density (ρeff) is closely associated with the aging process and can serve as a tracer of chemical composition. Recently, studies investigating the effect of particle size on density have been limited. In this study, size-resolved ρeff was characterized using a tandem aerodynamic aerosol classifier (AAC) and scanning mobility particle sizer (SMPS) system during 1 month of observations in Hangzhou. The results indicate that the ρeff values of the particles exhibit a unimodal distribution, with average values ranging from 1.47 to 1.63 g cm−3, increasing as the particle diameter increases. The diurnal variation is more pronounced for small particles (dae < 350 nm), which generally exhibit lower density during the day and higher density at night. The relationship between ρeff and particle diameter varies under different pollution conditions due to differences in the chemical composition of the particles. The SHapley Additive exPlanations (SHAP) values revealed good relationships between ρeff and the bulk composition of particles with diameters smaller than 350 nm, while the relationship with larger particles was weak. As determining the size-resolved chemical composition of particles remains challenging, a new method to investigate the size-resolved chemical composition was proposed, in which the size-resolved composition can be derived from the ρeff and fixed material density of secondary inorganic aerosols (SIAs), organic aerosols (OAs), and black carbon (BC).

Design and optimization of tubular oxygenation with pure oxygen for recirculating aquaculture systems

ABSTRACT Objective To address the facility complexities and costs of existing oxygenation with pure oxygen, a tubular oxygenation device primarily composed of a diffused stone and PVC pipes was designed for recirculating aquaculture systems demanding high or even supersaturated levels of dissolved oxygen (DO). Methods Introducing pure oxygen into a diffused stone forms the oxygen-containing bubbles in the horizontal pipe with an outer diameter of 50 mm and a wall thickness of 3.5 mm. These bubbles are subsequently transferred into the vertical pipe with an enlarged diameter via a 90° elbow fitting. To improve oxygenation performance, the water inflow velocity and the vertical pipe were optimized using the oxygen increment rate and the oxygen utilization rate as indicators. Pure oxygen with a flow rate of 1.79 L/min generated from an oxygen generator and tap water at 11.3°C were adopted for the experiments. Results The concentration of DO and the oxygen increment rate were positively correlated with the outer diameter and the length of the vertical pipe, whereas they were negatively correlated with the water inflow velocity. The maximum DO was 21.29 mg/L and the oxygen increment rate was 78.73% at a water inflow velocity of 0.4 m/s through a vertical pipe with an outer diameter of 110 mm and a length of 40 cm. With the increase in the outer diameter and length of the vertical pipe, the oxygen utilization rate improved at the same water inflow velocity. Specifically, the oxygen utilization rate reached a peak of 15.87% at a water inflow velocity of 0.8 m/s through a vertical pipe with an outer diameter of 110 mm and a length of 40 cm. Conclusions The tubular oxygenation should accurately manage the water velocity in the vertical pipe. To achieve the better oxygen increment rate and oxygen utilization rate simultaneously, it is recommended to regulate the water inflow velocity to approximately 0.6 m/s by utilizing a vertical pipe with an outer diameter of 110 mm and a length of 40 cm. This study provides an alternative method of oxygenation with pure oxygen for recirculating aquaculture systems.

Effect of SiO2 and TiO2 nanoparticles through foliar and root dipping treatments: a comprehensive comparison of growth, photosynthesis, secondary metabolites, redox status and enzyme responses in Ocimum sanctum

Nanotechnology shows potential to promote sustainable and productive agriculture and address the growing population and food demand worldwide. Recently, there has been an increase in interest in using nanoparticles (NPs) in agriculture. The current investigation aimed to examine the effects of two different NPs, SiO2 or TiO2 as foliar spray or root dipping treatment on tulsi (Ocimum sanctum L.) to identify the optimal concentration of SiO2 and TiO2 NPs that influence the growth, physiology, and biochemical processes of tulsi. The findings suggest that the treatment of SiO2 or TiO2 NPs led to an increase in peltate glandular trichomes (PGTs) density and diameter, chlorophyll content, photosynthesis, gas exchange traits, and elemental status; which led to enhancement of shoot and root length, fresh and dry mass of shoot and root, leaf area and leaf per plant. The application of SiO2 or TiO2 NPs led to the stimulation of enzyme activity responsible for maintaining carboxylation/decarboxylation homeostasis (carbonic anhydrase), nitrogen metabolism (nitrate reductase), Calvin cycle (RuBisCo), and TCA cycle (succinate dehydrogenase and fumarase). In addition, SiO2 or TiO2 NPs also played a crucial role in preserving a balance between reactive oxygen species (ROS) and the scavenging system by maintaining elevated activities of antioxidant enzymes involved in ROS detoxification. In the comparison between the two modes of treatment foliar treatment exhibited a more promising response compared to root dipping. SiO2 and TiO2 NPs increased Ocimum sanctum growth, physiology, and biochemical traits, with foliar application showing superior effects over root dipping. These NPs improve photosynthesis, enzyme activity, and antioxidant defense, making them promising for sustainable agriculture. Future studies should focus on long-term impacts, optimal dosages, and environmental safety to ensure their effective use in crop production.

Multi-therapeutic strategy targeting Akt-mTOR and FoxO1 pathway to counteract skeletal muscle atrophy consecutive to hypoxia.

Chronic oxygen deprivation, whether due to high altitude or certain diseases as cardiorespiratory pathologies, leads to muscle atrophy. To limit muscle loss, counteracting programs rely on only one therapeutic approach: return to sea level altitude, physical activity or nutritional supplementation; however, little effects are noticed on muscle mass of subjects presenting a severe hypoxemia. We hypothesized that the combination of several treatments (electrical stimulation and/or nutritional supplementation and/or oxygenation) would improve anabolic responses, counteracting thus efficiently hypoxia-induced muscle atrophy. In C2C12 myotubes submitted to hypoxia, we aim at testing several treatments based on the combination of electrical stimulation, amino acids supplementation and/or an oxygenation period. In comparison to untreated muscle cells under hypoxia, all treatments had an anabolic impact on myotubes morphology (myogenic fusion index, diameter and density of myotubes), on proteosynthesis pathway (Akt, mTOR, GSK-3β, 4E-BP1 and P70S6K), on proteolysis pathway (FoxO1, myostatin, ubiquitin-proteasome system) and on hypoxia marker (REDD1) protein level. Electrical stimulation alone resulted in hyperphosphorylation of Akt and FoxO1 while its combination with amino acids supplementation alleviated atrophy exemplified by fusion index and myotubes diameter increase up to 48 hours post-application. Electrical stimulation followed by a period of oxygenation of hypoxic muscle cells strongly increased the activation status of 4E-BP1 and P70S6K. Lastly, simultaneous application of all treatments (electrical stimulation, amino acids supplementation and oxygenation) was the only condition resulted in activation of mTOR concomitantly to myostatin level decrease. These results support that the activation of the mTOR pathway through the combined application of electrical stimulation and BCAAs is strongly influenced by oxygen availability, and that oxygen plays a critical role in optimizing protein synthesis pathway in hypoxic skeletal muscle cells.

Obtaining Polyacrylonitrile Carbon Nanofibers by Electrospinning for Their Application as Flame-Retardant Materials.

The article describes obtaining polyacrylonitrile (PAN) nanofibers by electrospinning on a setup developed at the Mendeleev University of Chemical Technology of Russia (MUCTR). A technique for producing PAN-based carbon nanofibers (CNFs) and PAN-based CNFs modified with titanium oxide (TiO2) is presented. The article presents a comprehensive study of the characteristics of PAN-based nanofibers and CNFs, including an analysis of the external structure of the fibers, the dependence of fiber diameters on the viscosity of the initial solutions, the effect of temperature treatment on the functional groups of PAN, elemental analysis, and flame-retardant properties. It was found that the fiber diameter and its external structure strongly depend on the viscosity of the initial solutions; an increase in viscosity leads to a linear increase in the fiber diameter. Preliminary temperature treatment at 250 °C helps stabilize PAN nanofibers and prevents their melting at the carbonization stage. The differential scanning calorimetry results allowed us to determine the presence of peaks for the initial PAN nanofibers, indicating an exothermic process in the temperature range of 290-320 °C. The peak height decreased with increasing TiO2 concentration in the samples. For CNF samples of different compositions, the endothermic effect prevailed in the temperature range of 400-700 °C, indicating the possible flame-retardant properties of these materials. The limiting oxygen index (LOI) was calculated based on the thermogravimetric analysis results. The highest LOI values were obtained for CNFs based on PAN without adding TiO2 nanoparticles and CNFs modified with TiO2 (3 wt.%). The resulting CNF-based nonwovens can be recommended for use in heat-protective clothing, flame-retardant mattresses, and flame-retardant suits for the military.

Numerical investigation and estimation method of leakage behaviour for hydrogen-blended natural gas in overhead pipelines

Blending hydrogen into existing natural gas pipelines can cause hydrogen embrittlement, which further leads to pipeline leakage and even serious explosions. Therefore, a mathematical-physical model is established for the leakage of hydrogen-blended natural gas (HBNG) based on species transport in this paper. The model is validated by the experimental values from the literature, with validation errors falling below 15%. The influence of different operating and structural parameters is analyzed on the leakage rate of HBNG. The results show that the leakage rate decreases with the hydrogen blending ratio increasing, it increases with an increase in leakage hole diameter and operating pressure, but it is poorly affected by the pipeline diameter and wall thickness. The orthogonal design is used in this simulation to analyse the effect of different factors on the leakage rate. The sensitivity for each factor ranks as follows: leakage hole diameter > hydrogen blending ratio > operating pressure > wall thickness > pipeline diameter. Finally, a new prediction model of leakage rate for HBNG is proposed, and the prediction deviation of that is less than 5%. The above results can be used as guidance for risk assessment and prevention of leakage accidents for HBNG in high-pressure overhead pipelines.