Greater Effect Research Articles

Curcumin activates the JNK signaling pathway to promote ferroptosis in colon cancer cells.

Recent evidence has proved that curcumin as a natural polyphenol have a great anticancer and anti-proliferative effects in cancer cells. Ferroptosis, a new form of regulated cell death, plays a vital role in the pathogenesis and therapy of cancers. In this study, we aimed to examine the effects of curcumin in ferroptosis of human colorectal cancer cells and its underlying molecular mechanisms. SW-480 colorectal cancer cells were treated by curcumin with different concentrations. Cell viability was determined by using MTT assay. The concentrations of reactive oxygen species (ROS) and intracellular iron were measured using specific related kits. Real-time PCR and Western blot analysis were used to determine the expression of ferroptosis-related proteins including ACSL4, GPx4 and FTH1 and activation of JNK protein. Curcumin suppressed SW-480 cancer cells viability in dose-dependent manner. Cell treatment with curcumin led to accumulation of ROS and iron within cells and increase in the intracellular levels of lipid peroxidation. In addition, curcumin modulated the mRNA and protein expression levels of ferroptosis-related proteins including ACSL4, GPx4 and FTH1 and suppression of JNK signaling. Curcumin may exhibit its anticancer effect on colorectal cancer by downregulating JNK signaling to induce ferroptosis in SW-480 cells.

Исследование нефтеемкости природных опоков Астраханской области

The article deals with the issues of studying the absorption capacity of oil and petroleum products (oil capacity) by a natural sorbent- the flask of the Central Kamennoyarsk field of the Astrakhan region. The study of oil capacity makes it possible to determine the possibility of using natural flakes as oil sorbents to collect oil and more viscous petroleum products from the surface of soils and hard coatings. In this work, the influence of the granulometric composition of the sorbent, the sorption temperature and the viscosity characteristics of oil and petroleum products on the oil capacity of the sorbent is studied. The regularities of the absorption capacity of natural flakes in the presence of oil, fuel oil, oil, gasoline and diesel fractions at temperature range from –5 to 40°C have been established. To determine the oil capacity, a static research method was used, in which the sorbent was not subjected to mechanical mixing during contact with the petroleum product. Thus, when testing sorbent fractions with particle sizes less than 1 and 2.5 mm it was stated that high oil capacity results (0.79-0.88 g/g) were achieved at temperature range from –5 and 20ºC in the presence of fuel oil and oil. The greatest sorption effect is achieved due to the influence of external adsorption and the adhesive action of high-viscosity petroleum products. A further increase in temperature to 40ºC reduces the viscosity of petroleum products and prevents the formation of a stable mixture with the sorbent. Relatively low values of the sorption capacity were obtained in the presence of watered oil. Regardless of the temperature, the oil capacity does not exceed 0.75 g/g. The collection of gasoline and diesel fuel is ineffective due to their low viscosity and high volatility.

Impact of digitization on carbon productivity: an empirical analysis of 136 countries

Enhancing carbon productivity (CP) is key to achieving carbon reduction goals while maintaining economic growth. Digital technology plays a significant role in improving CP. Based on panel data from 136 countries worldwide from 2000 to 2020, this study empirically examines the impact of digitalization on CP and its mechanisms using fixed-effects and mediation models. The conclusions are as follows: (1) Overall, digitalization significantly enhances CP. (2) In terms of the mechanism, digitalization primarily improves CP through technological innovation and mitigating income inequality. (3) In terms of the quantile regression results, as the quantile level of CP increases, the promoting effect of digitalization on CP gradually strengthens. (4) From the perspective of heterogeneity among regions, income levels and human capital levels, digitalization has the greatest promotion effect on carbon productivity in European countries, high-income countries and high human capital countries. This study provides a reference for policymakers worldwide to use digital technology in achieving carbon emission reduction targets.

Trophic interactions in soil micro-food webs drive ecosystem multifunctionality along tree species richness.

Rapid biodiversity losses under global climate change threaten forest ecosystem functions. However, our understanding of the patterns and drivers of multiple ecosystem functions across biodiversity gradients remains equivocal. To address this important knowledge gap, we measured simultaneous responses of multiple ecosystem functions (nutrient cycling, soil carbon stocks, organic matter decomposition, plant productivity) to a tree species richness gradient of 1, 4, 8, 16, and 32 species in a young subtropical forest. We found that tree species richness had negligible effects on nutrient cycling, organic matter decomposition, and plant productivity, but soil carbon stocks and ecosystem multifunctionality significantly increased with tree species richness. Linear mixed-effect models showed that soil organisms, particularly arbuscular mycorrhizal fungi (AMF) and soil nematodes, elicited the greatest relative effects on ecosystem multifunctionality. Structural equation models revealed indirect effects of tree species richness on ecosystem multifunctionality mediated by trophic interactions in soil micro-food webs. Specifically, we found a significant negative effect of gram-positive bacteria on soil nematode abundance (a top-down effect), and a significant positive effect of AMF biomass on soil nematode abundance (a bottom-up effect). Overall, our study emphasizes the significance of a multitrophic perspective in elucidating biodiversity-multifunctionality relationships and highlights the conservation of functioning soil micro-food webs to maintain multiple ecosystem functions.

How Do Birth Satisfaction, Perceived Stress, and Some Factors Affect the Risk of Postpartum Depression?

This research was carried out to determine the effects of birth satisfaction, perceived stress level and some factors on postpartum depression (PPD). In the study; cross-sectional, descriptive, correlational and predictive research designs were used. 446 women who met the inclusion criteria participated in the study. The average age of the women was 28.48±57.14 (min-max: 19-44). While 13.9% of women were at risk of PPD and there was a negative and moderate relationship between birth satisfaction and PPD risk (r=-0.403), a negative but low-level significant relationship was obtained between perceived stress (r=-0.325). Among the socio-demographic variables, the education level has the highest impact, while among the obstetric characteristics, the disease status of the baby has the highest impact. Perceived stress has the greatest effect compared to all variables. In this study risk of PPD; It was determined that birth satisfaction had a negative effect and perceived stress had a positive effect. Among the socio-demographic characteristics; age (35 years and above), education level; place of residence, obstetric characteristics; It was concluded that pregnancy planning, pregnancy problems, baby’s health, pregnancy follow-up and birth support factors are effective on the risk of PPD.

Quantitative Assessment of the Effect of Agency-Led Prescribed Burns and Cultural Burns on Soil Properties in Southeastern Australia

Fire management techniques play a critical role in mitigating the impact of bushfires on communities and ecosystems. In Australia, government agencies implement hazard reduction burn programs, while Indigenous communities have used fire for ecosystem management for thousands of years. The positive effect of prescribed burning goes beyond bushfire risk mitigation, with impacts also on soil and ecosystem health. This study evaluates the effects of prescribed burning on soil properties, with implications for soil and ecosystem health. Two fire management techniques were evaluated: agency-led prescribed burning and cultural burning. Both fire treatments resulted in an increase in soil moisture, showing that they positively affect the soil water balance (the greater effect seen following the agency-led burn). Both fire treatments also resulted in a decrease in soil bulk density and an increase in organic matter content, with the greater effect seen for soils affected by the Indigenous-led burn. These results show that both fire management techniques positively affect soil health, with important consequences for aboveground ecosystem health. Cultural burning is the most efficient to promote reduced soil bulk density (important for nutrient availability and microbial activity) and increase carbon and nitrogen stores.

Numerical simulation of single-jet impact cooling and double-jet impact cooling of hot-rolled L-shaped steel based on multiphase flow model

In this paper, numerical simulations of single-jet impingement cooling and double-jet impingement cooling processes of heated L-shaped steel are carried out using the VOF model. The SIMPLEC pressure–velocity coupling algorithm and realizable k-ε model are used for the solution. The effects of jet position, water flow, and jet distance in the single-jet condition are analyzed in the simulations. The distributions of impact pressure, turbulence kinetic energy, and Nusselt number were obtained, as well as the variation of the peak values of these three factors with the jet position, water flow, and jet distance. The water flow rate is 3–11 L/min, and the jet distance is 5–25 cm. The effect of the distance between the two nozzles on the jet cooling uniformity under the dual jet condition was also analyzed. The distance between the two nozzles was 15–45 mm. The results showed that the variation of water flow rate had a greater effect on the ability of jet cooling compared with the jet position and jet distance, and the heat transfer efficiency also increased gradually with the increase of water flow, but the increased rate of heat transfer efficiency decreased gradually. When the flow rate increased from 3 to 11 L/min, the maximum instantaneous cooling rates at 1/4 of the thickness of the short side upper side, long side upper side, short side lower side, and long side lower side positions increased by 38.9%, 48.5%, 48.2%, and 32.9%, respectively. To ensure that the jet does not shift, the jet distance should be less than or equal to 10 cm. In the case of the double jet, the nozzle distance is 1.5 cm, and the cooling uniformity of the cooling area between the two nozzles is better. The peak Nusselt number in the cooling area of each part under the double jet cooling condition increased by 5%, 9.4%, 10.2%, and 13.3%, respectively, compared with the single jet.

The Importance of Social Support for Individuals on Specialized Probation: A Gender Comparison of Relapse and Revocation

Informed by social support theory, this study examined gender differences of revocation and relapse of 526 probationers diagnosed with a substance use disorder, mental health disorder, or co-occurring disorder who were court-ordered for treatment. Within 18 months of starting probation, 51% of men and 56% of women were revoked. Although not statistically significant, the relapse rate was 34% for women and 26% for men. Significant predictors of revocation were similar across gender with a lack of family support being the strongest predictor for both groups, though notably stronger for women. Family support was a significant predictor of relapse for women but not for men. Inpatient treatment of at least 180 days had the greatest effect in reducing relapse and revocation for women. Treatment dosage of at least 90 days had modest effects in reducing men’s revocation, but the treatment effect was less pronounced for men’s relapse rates.

Multiple Myeloma Derived Extracellular Vesicle Uptake by Monocyte Cells Stimulates IL-6 and MMP-9 Secretion and Promotes Cancer Cell Migration and Proliferation.

Multiple Myeloma (MM) is an incurable haematological malignancy caused by uncontrolled growth of plasma cells. MM pathogenesis is attributed to crosstalk between plasma cells and the bone marrow microenvironment, where extracellular vesicles (EVs) play a role. In this study, EVs secreted from a panel of MM cell lines were isolated from conditioned media by ultracentrifugation and fluorescently stained EVs were co-cultured with THP-1 monocyte cells. MM EVs from three cell lines displayed a differential yet dose-dependent uptake by THP-1 cells, with H929 EVs displaying the greatest EV uptake compared to MM.1s and U266 EVs suggesting that uptake efficiency is dependent on the cell line of origin. Furthermore, MM EVs increased the secretion of MMP-9 and IL-6 from monocytes, with H929 EVs inducing the greatest effect, consistent with the greatest uptake efficiency. Moreover, monocyte-conditioned media collected following H929 EV uptake significantly increased the migration and proliferation of MM cells. Finally, EV proteome analysis revealed differential cargo enrichment that correlates with disease progression including a significant enrichment of spliceosome-related proteins in H929 EVs compared to the U266 and MM.1s EVs. Overall, this study demonstrates that MM-derived EVs modulate monocyte function to promote tumour growth and metastasis and reveals possible molecular mechanisms involved.

COVID-19 vaccine hesitancy and conspiracy beliefs in Togo: Findings from two cross-sectional surveys.

Togo is a low-income country in West Africa. Estimates from Our World in Data suggest that only 25% of the Togolese population have received at least one dose of any COVID-19 vaccine by June 2023. Whilst the early phase of the pandemic vaccine rollout across 2021 was dominated by higher-income countries taking much of the available supply, there have long been sufficient supplies for all nations. Thus, there remains a need to understand reasons for low uptake in countries such as Togo, here focusing on population confidence and trust, essentially characteristics that could potentially be addressed within health promotion strategies. Two cross-sectional telephone surveys of Togo residents were conducted in December 2020 and January 2022. These surveys asked questions around perceptions of COVID-19, trust in public health messaging, belief in conspiracy theories, and hesitancy around COVID-19 vaccination. Analyses here focus on unvaccinated respondents. Across Survey 1 (N = 1430) and Survey 2 (N = 212), 65% of respondents were men, and 47% lived in Lomé (capital city of Togo). Between Surveys 1 and 2, overall hesitancy (33.0% to 58.0% respectively) and beliefs in conspiracy theories (29% to 65%) significantly increased. Using logistics regression, governmental mistrust was the strongest significant predictor of hesitancy (OR: 2.90). Participants who indicated agreement or uncertainty with at least one conspiracy belief also predicted greater vaccine hesitancy (OR: 1.36). Proactive approaches to public health messaging, that better understand reasons for hesitancy across different demographics, can support uptake of COVID-19 vaccinations within Togo. This includes health promotion campaigns that use locally and nationally trusted knowledge providers (e.g. the health service or religious leaders) for greatest effectiveness at reducing impact of misinformation. Key future research should focus around knowledge gaps and areas of mistrust created by the pandemic, such as the impact of misinformation upon routine immunisation uptake.

Removal of Anabaena by ultrasonic pretreatment enhancing-coagulation and water treatment processes

Cyanobacteria bloom brings great challenges to the safety of the drinking water process. Ultrasonic pretreatment can effectively enhance coagulation to remove algae cells from algae-laden water. However, due to the special chain-like structure of Anabaena, the removal characteristics of Anabaena in water treatment process are quite different from those of unicellular cyanobacteria. No study has yet systematic studied on the enhancement effect of ultrasonic enhanced water treatment process on Anabaena. Therefore, this paper studied the characteristics and mechanism of ultrasonic pretreatment to enhance the removal of Anabaena, and carried out pilot experiments. The results showed that ultrasound irradiation at 740 kHz and 1.12 MHz had a great effect on the destruction of the chain-like structure and cell structure of Anabaena. After 15 min, the removal rate of Anabaena cells reached 16.0% and 30.4%, respectively, and the release of intracellular organic matter (IOM) reached 4.3 and 6.0 mg/L, in which phycocyanin released more. The damage of dynamic ultrasound irradiation on algae cells is weak, which can avoid the influence of uneven ultrasound irradiation on algae cells. The enhanced coagulation effect was better after 740 kHz ultrasonic pretreatment for 1 min, and the removal rates of algal cells, turbidity and dissolved organic carbon (DOC) increased by 7%, 9.4% and 12.6%, respectively. Pilot scale experiments demonstrate that ultrasonic pretreatment leads to a notable enhancement in the removal efficiency during the coagulation and sedimentation stages. After 4 h of operation, the turbidity and algal cell removal in the sedimentation stage increased by 6.1% and 14.0%, respectively. In addition, the removal of DOC in the final treated water increased by 6.7%. Furthermore, the disinfection by-products (DBPs) concentration experiences a reduction exceeding 200 μg per liter. Together, these results show a substantial improvement in filtration efficiency and effluent quality. This study provides guidance for the ongoing study of ultrasonic pretreatment to remove chain-like cyanobacteria.

Study on fracture characteristics and fracture mechanism of fully recycled aggregate concrete using AE and DIC techniques

Fracture behaviors of manufactured sand-recycled coarse aggregate concrete (MSRCAC), recycled fine aggregate concrete (RFAC), and fully recycled aggregate concrete (FRAC) were investigated by performing three-point bending tests on single-edge notched beams using acoustic emission (AE) and digital image correlation (DIC) techniques. The effects of recycled fine aggregate (RFA), recycled coarse aggregate (RCA), and their interaction on fracture parameters, AE characteristics and fracture process zone (FPZ) of concrete were comparatively analyzed. The results indicated that it was mainly transgranular failure and intergranular failure for RFAC, while transgranular failure for MSRCAC and FRAC. The RFA and RCA reduced the initial fracture toughness, unstable fracture toughness and fracture energy of concrete, and their interaction resulted in poor fracture properties of FRAC. In addition, the RFA and RCA significantly increased the AE activities, the proportion of tensile cracks, and the high-frequency amplitude and peak frequency of concrete. The toughening effect of FPZ was weakened by the RFA and RCA, resulting in an obvious increase in FPZ length and damage propagation of FRAC. Meanwhile, the width of FPZ was reduced, the maximum FPZ width of concrete with different combinations of recycled aggregates was approximately 1.8–3.1 times the maximum aggregate size, which could be explained as the RFA and RCA reduced the aggregate interlocking effect of concrete, while the RCA had a greater effect on the damage mechanism and FPZ of concrete than the RFA.

From "Additive-Free" to "Tobacco & Water": Assessing the Impact of Marketing Claim Changes on Natural American Spirit and L&M Cigarettes.

The 2017 agreement between the U.S. Food and Drug Administration and the makers of Natural America Spirit (NAS) cigarettes restricted the use of "additive-free" (AF) in brand marketing, which the company replaced with "tobacco ingredients: tobacco & water" (TW), a phrase subsequently adopted by L&M. We tested how participants' perceptions differed when exposed to AF versus TW claims on NAS and L&M packs. A between-subjects experiment was embedded within an online survey in August 2022 (n = 2526). Participants were randomized to view one of three packs (NAS AF pack, NAS TW pack, L&M TW pack). Logistic regressions assessed differences (by pack exposure) in perceived pack attractiveness and relative chemical and harm perceptions compared to other cigarettes. Interactions by smoking status were explored. No significant differences were observed between the NAS AF and NAS TW packs on perceived attractiveness or relative harm, although never smokers had higher odds of having lower relative chemicals perceptions in response to the NAS AF versus NAS TW pack (OR = 1.81). Compared to participants who saw the NAS TW pack, those who saw the L&M TW pack tended to have lower odds of perceiving the pack as attractive, believing that the product had fewer chemicals than other products, or believing the product was less harmful than other products compared to the NAS TW pack. Results suggest the more implicit "tobacco ingredients: tobacco & water" claim functions similarly to "additive-free" and as an unauthorized modified risk claim. NAS brand image also appears to contribute to higher perceived pack attractiveness and lower perceptions of chemicals and harm. Additional marketing regulations and corrective campaigns may be needed to reduce risk-related misperceptions about NAS cigarettes. Our findings show that replacing "additive-free" claims with "tobacco ingredients: tobacco & water" did not sufficiently address the illegal use of unauthorized modified risk claims by the makers of NAS cigarettes. Further regulatory action restricting the TW claim could potentially reduce inaccurate lower harm perceptions about NAS cigarettes. Educational campaigns may also be needed to mitigate NAS's history of marketing that implies reduced harm, given that the effects of implicit reduced risk claims like TW have a greater effect on pack perceptions for NAS than L&M.

Development of a system for controlling a diamond drilling mode in terms of rock fault resistance

Relevance. Resistance to rock-cutting elements in rock destruction largely determines the effectiveness of drilling results. Information about the drag coefficient allows you to correctly and timely adjust the intensity of a drilling tool impact on the bottom of the well. To control the force contact of the drilling tool cutters with the bottom of the well, it is necessary to have a methodological apparatus that allows determining the rock destruction mechanism, taking into account the resistance forces. The existing methods for selecting combinations of diamond drilling mode parameters according to the known RPI index or according to the criterion of energy intensity of rock destruction N/vm , where N is the bottomhole power to overcome the resistance during rock destruction at the bottom hole; vm – mechanical drilling speed, have a number of disadvantages. They consist, for example, in occurrence of tool wear or the need to obtain a bottomhole power value in the current time mode, which is difficult under modern drilling conditions. Therefore, the study of rock resistance to destruction by a diamond cutter, based on application of the full factorial experiment method with obtaining mathematical models of factors and their graphical interpretation in combination with process control systems using computer technology in the current time mode, is a relevant topic. The disclosure of this topic will determine the direction of increasing technical and economic indicators of drilling. Aim. To develop a methodological apparatus that allows determining the mechanism of rock destruction taking into account the resistance forces to ensure optimal control of diamond drilling. Objects. Mechanism of rock resistance to destruction by a diamond cutter. Methods. Analysis, analytical research, full factorial experiment. Results. The paper presents an analytical analysis of the possibility of controlling drilling modes in order to achieve the greatest effect from drilling by estimating the drag coefficient as a function of the intensity of destruction or deepening per one revolution. Based on the analytical studies and the mode of drilling control by a computer in the real time mode, the authors have proposed a method for selecting the parameters of the drilling mode according to a given optimal value of the resistance index during drilling, and a way for its automatic implementation.

Analysis of the influence of ions on degradation of benzamide with hydrodynamic cavitation technology

In recent years, hydrodynamic cavitation technology has become a research hotspot in various fields. This study establishes a benzamide model with different ion types, ion concentrations, and bubble radii. The model is used to study the diffusivity of water molecules on the benzamide wall and structural changes in benzamide. The influence of ion type, ion concentration, and bubble radius on the degradation of pollutants is examined. The results are as follows: the larger the bubble radius and ion concentration, the larger the rate of change of maximum radial distribution function of carbon atoms (w). The effect of ion type on the diffusion coefficient of water molecules on the benzamide wall is as follows: H2O2 > HCO3−1 > NO3−1. In terms of structural changes in the benzamide, in the model containing H2O2, ion concentration has a greater effect than bubble radius. In the model containing HCO3−1, bubble radius has a greater effect than ion concentration. In the model containing NO3−1, bubble radius and ion concentration have an equal effect. w decreases most in the model containing H2O2 and least in the model containing NO3−1. The model containing H2O2 produces the most powerful effect in benzamide pollutant degradation. This study provides technical guidance and a theoretical basis for the green treatment of pollutants using cavitation theory.

Effects of Triazole Antifungal Agents on the Plasma Concentration and Dosage of Cyclosporin in Patients with Aplastic Anaemia

Objectives. This study aimed to investigate the effects of different triazole antifungal agents on the blood concentration and dosage of cyclosporine (CsA) in patients with aplastic anaemia (AA). Methods. This retrospective study enrolled AA patients who received CsA and triazole antifungal agents simultaneously between January 2018 and December 2022. The ratio of CsA blood concentration (ng/mL) to dosage (mg/day) (C/D) co-administration with and without azoles was compared. The effects of different triazole antifungal agents on blood concentrations and dosages of CsA were analysed. Results. The mean C/D ratio of CsA increased 1.97 times when co-administered with posaconazole (POS), while the mean C/D ratio of CsA increased 1.76 times when co-administered with fluconazole (FCZ). Compared with CsA monotherapy, there was a significant difference in CsA concentrations among patients with azoles (P<0.05). The mean dose of CsA decreased was 0.26 (−0.25—1.05) mg/kg/day and 0.18 (−0.50—0.69) mg/kg/day when co-administered with POS and FCZ, respectively. There is a wide interindividual variability in the magnitude of drug interaction between azoles and CsA. Conclusions. Although azoles increased CsA concentration, a wide individual variability was found in the patients with CsA C/D ratio. Therefore, the CsA dose should be adjusted by closely monitoring the blood levels of CsA co-administered with triazole antifungal agents. In addition, we observed that POS had a greater effect on the blood concentration of CsA than FCZ. When adjusting the dose of CsA in clinical practice, the blood concentration of CsA and the type of co-administered triazole antifungal agents should be considered.

Explainable ensemble machine learning revealing the effect of meteorology and sources on ozone formation in megacity Hangzhou, China

Megacity Hangzhou, located in eastern China, has experienced severe O3 pollution in recent years, thereby clarifying the key drivers of the formation is essential to suppress O3 deterioration. In this study, the ensemble machine learning model (EML) coupled with Shapley additive explanations (SHAP), and positive matrix factorization were used to explore the impact of various factors (including meteorology, chemical components, sources) on O3 formation during the whole period, pollution days, and typical persistent pollution events from April to October in 2021–2022. The EML model achieved better performance than the single model, with R2 values of 0.91. SHAP analysis revealed that meteorological conditions had the greatest effects on O3 variability with the contribution of 57 %–60 % for different pollution levels, and the main drivers were relative humidity and radiation. The effects of chemical factors on O3 formation presented a positive response to volatile organic compounds (VOCs) and fine particulate matter (PM2.5), and a negative response to nitrogen oxides (NOx). Oxygenated compounds (OVOCs), alkenes, and aromatic of VOCs subgroups had higher contribution; additionally, the effects of PM2.5 and NOx were also important and increased with the O3 deterioration. The impact of seven emission sources on O3 formation in Hangzhou indicated that vehicle exhaust (35 %), biomass combustion (16 %), and biogenic emissions (12 %) were the dominant drivers. However, for the O3 pollution days, the effects of biomass combustion and biogenic emissions increased. Especially in persistent pollution events with highest O3 concentrations, the magnitude of biogenic emission effect elevated significantly by 156 % compared to the whole situations. Our finding revealed that the combination of the EML model and SHAP analysis could provide a reliable method for rapid diagnosis of the cause of O3 pollution at different event scales, supporting the formulation of control measures.

Influence of Polymer Fibers on the Structure and Properties of Modified Variatropic Vibrocentrifuged Concrete.

The application of polymer materials in concrete structures is widespread and effectively used. However, there is a lack of a systematic knowledge base about the structure formation and properties of variatropic vibrocentrifuged modified fiber-reinforced concrete. The purpose of this work is the investigation of the influence of polypropylene (PF) and basalt fiber (BF) and modification with microsilica (MS) on the properties of variatropic concretes obtained using the synthesized vibration centrifugation technology. Test samples were made using vibration centrifugation technology, followed by sawing. Various types of fiber reinforcement were studied, both individually and in combination. To determine the degree of effectiveness of each recipe solution, the following main characteristics were monitored: the density and workability of concrete mixtures; the density of hardened composites; compressive strength (CS); bending strength (BS); water absorption (WA). In variatropic vibrocentrifuged concrete, the greatest efficiency is achieved with dispersed BF reinforcement in an amount of 1.5%. Compared to the control composition, the increase in CS was 8.50%, the increase in BS was 79.17%, and WA decreased by 27.54%. With PF reinforcement, the greatest effect was recorded at a dosage of 1.0%. The increase in CS was 3.16%, the increase in BS was 10.42%, and WA decreased by 17.39%. The MS modification showed the best effect with 8% replacement of part of the Portland cement. The increase in CS was 17.43%, the increase in BS was 14.58%, and WA decreased by 33.30%. The most effective and economically rational formulation solution for vibrocentrifuged concrete is combined fiber reinforcement in combination with the MS modification in the following quantities: BF-1.0%; PF-0.5%; MS-8%. The increase in CS was 22.82%, the increase in BS was 85.42%, and WA decreased by 37.68%.

Numerical study of effective parameters on true triaxial test results in rigid type apparatus

Operational parameters in true triaxial loading devices (TTA), such as the loading rod dimensions, friction between the loading platens and sample faces, loading gap, and one-side loading may affect the test results. Knowledge of the effect of each parameter is very important to correctly interpret rock behavior and to optimize these devices. Employing the Flac3D finite difference software, a rigid type true triaxial systemdesigned and builtat Amirkabir University of Iran (AUT-TTA) was simulated andinvestigated in this study. The results indicate that increasing the ratio of the rod cross-section to the loading platen area leads to an increase in the sample confinement, so, more uniform stress distribution occurs in the rock sample. The loading gap reduces strength of the rock specimen and leads to concentration of tensile stresses at the sample edges. The end effect leads to an increase in the stress level and a pseudo-hardening behavior in the samples. Also, the end effect is intensified under one-side loading condition compared to two-side loading. Comparison between results of AUT-TTA numerical simulation and analytical analysis (ideal conditions without considering operational parameters) indicates that the slope of the stress–strain diagram has low sensitivity to operational parameters. The most important operational factor affecting the stress level and dilatation stress is the end effect and other operational parameters have little effect. All parameters lead to an increase in the dilation strain. The clear edge and one-sided loading under low intermediate principal stresses and the end effect under high intermediate principal stresses have the greatest effect on the dilation strain.

Effects of Caffeine-Taurine Co-Ingestion on Endurance Cycling Performance in High Temperature and Humidity Environments.

Taurine (TAU) and caffeine (CAF), as common ergogenic aids, are known to affect exercise performance; however, the effects of their combined supplementation, particularly in high temperature and humidity environments, have not been studied. The combination of TAU and CAF will have a greater effect on endurance cycle performance and improve changes in physiological indicators during exercise compared with TAU or CAF supplementation alone and placebo. Single-blind crossover randomized controlled study. Level 1. Twelve university students majoring in physical education volunteered to receive 4 different supplement ingestions: (1) placebo (maltodextrin), (2) TAU, (3) CAF, (4) TAU + CAF. After a 7-day washout period, participants completed a time to exhaustion (TTE) test in the heat (35°C, 65% relative humidity). All experimental groups improved TTE compared with the placebo group. Peak and mean power of countermovement jump were significantly higher in the CAF group compared with the placebo group before the exhaustion exercise (P = 0.02, d = 1.2 and P = 0.04, d = 1.1, respectively). Blood lactate was significantly lower after the exhaustion test in the TAU group compared with the CAF (P < 0.01, d = 0.8) and TAU + CAF (P < 0.01, d = 0.7) groups. Core temperature in the TAU group was significantly reduced in the placebo group later in the exhaustion test (P < 0.01, d = 1.9). In high temperature and humidity environments, acute TAU, CAF, and combined supplementation all improved TTE and did not affect recovery from lower limb neuromuscular fatigue compared with placebo, with TAU having the best effect. Combined supplementation failed to exhibit superimposed performance. The results provide suggestions for the effects of TAU, CAF, and their combined intake on exercise performance in high temperature and humidity environments.