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Background There are few data on the prevalence of acquired drug resistance mutations (ADRs) in Hunan Province, China, that could affect the effectiveness of antiretroviral therapy (ART). Objectives The main objectives of this study were to determine the prevalence of acquired drug resistance (ADR) the epidemic characteristics of HIV-1-resistant strains among ART-failed HIV patients in Hunan Province, China. Methods ART-experienced and virus suppression failure subjects in Hunan between 2012 and 2017 were evaluated by genotyping analysis and mutations were scored using the HIVdb.stanford.edu algorithm to infer drug susceptibility. Results The prevalence of HIV-1 ADR were 2.76, 2.30, 2.98, 2.62, 2.23and 2.17%, respectively, from 2012 to 2017. Overall 2295 sequences were completed from 2932 ART-failure patients, and 914 of these sequences were found to have drug resistance mutation. The most common subtype was AE (64.14%), followed by BC (17.91%) and B (11.50%). Among those 914 patients with drug resistance mutations,93.11% had NNRTI-associated drug resistance mutations, 74.40% had NRTI drug resistance mutations (DRMs) and 6.89% had PI DRMs. Dual-class mutations were observed in 591 (64.66%) cases, and triple-class mutations were observed in 43 (4.70%) cases. M184V (62.04%), K103N (41.90%) and I54L (3.83%) were the most common observed mutations, respectively, in NRTI-, NNRTI- and PI-associated drug resistance. 93.76% subjects who had DRMs received the ART first-line regimens. CD4 count, symptoms in the past 3 months, and ART adherence were found to be associated with HIV-1 DR. Conclusions This study showed that although the prevalence of HIV-acquired resistance in Hunan Province is at a low-level, the long-term and continuous surveillance of HIV ADR in antiretroviral drugs (ARVs) patients is necessary.

This study evaluated the effects of no-till seeding and fertilization on the restoration of degraded grazing grasslands in Bayinbuluke. Poaceae species were selected for no-till replanting, with Elymus dahuricus, Puccinellia distans, and Festuca ovina mixed in a 2:1:1 ratio. Four sowing rates were applied: 0 g/m2 (A0), 2 g/m2 (A1), 4 g/m2 (A2), and 6 g/m2 (A3). Diammonium phosphate (N 18%, P2O5 46%) was used as fertilizer, with four fertilization rates: 0 g/m2 (B0), 7.5 g/m2 (B1), 15 g/m2 (B2), and 22.5 g/m2 (B3). A total of 16 treatments were applied. The study assessed the changes in grassland productivity, species diversity, and soil physicochemical properties. The results showed that no-till replanting significantly increased the aboveground biomass by 81%, species richness by 55.8%, and the Shannon–Wiener diversity index by 64.2%. Fertilization significantly increased productivity, with dry hay yield rising by 60.9% to 81%. When 22.5 g/m2 of fertilizer was applied, the contents of total phosphorus, total nitrogen, available phosphorus, and organic matter in the soil increased by 43.4%, 50.6%, 66%, and 31.2%, respectively. Fertilization also improved the stability of soil aggregates, with the proportion of large aggregates increasing by 18.2%. The findings suggest that no-till seeding and fertilization significantly promote grassland restoration, with soil moisture and nutrient availability being key drivers of vegetation growth and community diversity.

Grassland soil carbon stocks contain substantial amounts of organic carbon and play a crucial role in the global carbon cycle. Grazing is one of the most primary land use types in grasslands. However, few studies have focused on the impact of three grazing behaviors (mowing (M), trampling (T), and dung and urine addition (D)) on the soil organic carbon (SOC) of mountain meadows. In this experiment, we simulated three grazing behaviors to explore the impacts of grazing behaviors on plant characteristics with plant growth, soil physicochemical properties, soil aggregate, and analyzed the main factors influencing the changes in SOC. After six years of treatment, the experimental results showed that M significantly decreased plant height, density, and aboveground biomass and significantly decreased soil organic carbon (SOC) (no M vs. M, −3.64%). T significantly increased soil bulk density, the proportion of macroaggregates, the organic carbon of microaggregates, and silt and clay aggregates and significantly increasing SOC (no T vs. T, +3.17%). D significantly increased plant density, soil total nitrogen and the organic carbon of macroaggregates, significantly increasing SOC (no D vs. D, +9.74%). Correlation and principal component analyses indicated that SOC was significantly negatively correlated with soil bulk density and plant coverage and significantly positively correlated with soil total nitrogen, soil C/N, microaggregate proportion, and the organic carbon of macroaggregates. Redundancy analysis indicated that the proportion of microaggregates and the organic carbon of macroaggregates were the main factors influencing SOC. The following conclusions were drawn: SOC responds differently to three types of grazing behaviors, D primarily increases the organic carbon in macroaggregates, while T mainly enhances the organic carbon in microaggregates and silt and clay aggregates, thereby affecting the SOC in mountain meadows.

The safety issues triggered by thermal runaway is one of the most crucial problems to be considered for the development of Li-ion batteries. The series exothermic reactions during thermal runaway created a lot of heat and gas. The vented gas may ignite and cause excessive heat transfer to nearby surfaces, thus creating an extreme risk for propagating failures. The objective of this dissertation was to study the effect of safety vent geometry on the venting flow physics and subsequent heat transfer to nearby surfaces. Four commercially available Li-ion safety vents (MTI, LG MJ1, K2, and LG M36) were considered in this work. The safety vents were inspected, through computed tomography (CT) scanning, to understand the design and construction of each vent assembly. Experiments and simulations were conducted to compare several key venting parameters among the four designs: current interrupt device (CID) activation pressure, vent-activation pressure, and discharge flow coefficient. A semi-empirical model, based on flow through a sharp-edged orifice, was proposed for estimating mass flowrate through the safety vent. The model required a single geometric parameter, the sharp-edged equivalent area, which is inversely proportional to flow resistance. Computational fluid dynamics (CFD) was used to study the venting jet flow physics for each safety vent design. The geometric design of the CID mechanism strongly influenced the flowfield structure. Spot-weld CID designs, when compared to notch-groove CID designs, showed elevated turbulence levels within the safety vent assembly and showed a strong recirculation zone directly above the safety vent assembly. Heat transfer resulting from impingement of the vented jets onto a surface placed above the safety vent was measured experimentally and simulated using CFD. In general, heat transfer increased with increasing sharp-edged equivalent area. Also, safety vents with notch-groove CID designs exhibited elevated heat transfer rates when compared to spot-weld CID designs. Based on lessons learned from the flowfield and heat transfer analysis, an optimized safety vent design was proposed. The gas flow restriction was lowered by enlarging the equivalent area. The current collector component was modified to include a lobed mixing nozzle for the purpose of enhancing turbulence to mix the jet with the surrounding air, thereby reducing the jet temperature striking the target surface. Compared to the LG M36 design, the optimized safety vent increased the equivalent area by 58% without increasing the heat transfer rate.

Ecosystem services play a crucial role in maintaining ecological balance, providing essential functions. This study examines the trade-offs and synergies among five key ecosystem services in ecological forests across different regions of Hunan Province, China. Various machine learning models are compared to predict ecosystem service value (ESV) levels, with the most effective predictive model identified. The SHAP (SHapley Additive exPlanations) analysis is employed to identify key environmental and management factors influencing ecosystem services. Our findings reveal significant regional variations in ecosystem services, with the eastern and western regions showing superior soil conservation and forest nutrient retention. In contrast, the southern and western regions, particularly karst areas, display fewer trade-offs between ecosystem services, likely due to the effectiveness of ecological policies. SHAP analysis further reveals that factors such as precipitation during the warmest quarter, central government compensation funds, and timber harvesting volume strongly influence regional ESV. This study provides valuable insights for improving ecosystem service management and policy-making in rapidly developing regions, underscoring the importance of ecological protection strategies for sustainable development.

The co-occurring relationships between ilmenite and gangue minerals in ilmenite deposits, as well as fine mineral embedding particle sizes, are complex. During the beneficiation process, grinding ilmenite finely is necessary to achieve sufficient individual mineral dissociation and the efficient recovery of ilmenite. During this process, a large number of fine-grained minerals can easily be generated, which adversely affects flotation separation. Micro–nanobubbles have been proven to effectively enhance the flotation separation efficiency of fine-grained minerals, as their cavitation characteristics are closely related to the flotation performance of the minerals. In order to fully understand the cavitation characteristics of micro–nanobubbles and their impact on the flotation recovery of fine-grained ilmenite, a series of experiments were conducted using methods such as the bubble cavitation property test, micro-flotation experiments, zeta potential analysis, the contact angle test, adsorption capacity detection, and PBM monitoring. The results indicate that during the process of slurry cavitation, appropriate concentrations of 2-octanol, cycle treatment times, and external inflation volume are conducive to the formation of micro–nanobubbles. Compared with deionized water without cavitation, cavitated micro–nanobubble water is more beneficial for the flotation separation of fine particulate ilmenite, titanaugite, and olivine. The presence of micro–nanobubbles can effectively promote the adsorption of combined collectors on mineral surfaces, significantly enhancing the hydrophobicity of the minerals, with an even stronger promoting effect observed under the treatment of 2-octanol. Micro–nanobubbles can adsorb a portion of the collectors originally attached to the mineral surfaces, thereby decreasing the absolute value of the surface potential of the minerals, which is beneficial for mineral aggregation. The introduction of micro–nanobubbles promotes the aggregation of fine ilmenite iron ore particles into flocculent bodies. 2-Octanol can reduce the size of the micro–nanobubbles generated during the cavitation process of the mineral slurry and, to a certain extent, weaken the phenomenon of bubble coalescence, so they demonstrate a greater advantage in facilitating the aggregation phenomenon.

Continuous bioreactors for petroleum degradation and the effect factors of these bioreactors have rarely been mentioned in studies. In addition, indigenous bacteria living in seawater could influence the performance of continuous bioreactors with respect to petroleum degradation in practice. In this paper, a bioreactor fitted with immobilized petroleum–degrading bacteria beads was designed for further research. The results indicated that the diesel degradation rate of the bioreactor could remain above 50% over 27 days, while degradation performance decreased with bioremediation time. Intriguingly, the diameters of immobilized petroleum–degrading bacteria beads were reduced by 32.49% after 45 days remediation compared with the initial size of the immobilized petroleum–degrading bacteria beads. Change in immobilized petroleum–degrading bacteria beads was considered to correlate remarkably with reduced degradation efficiency. Therefore, this paper will be helpful for further study and improvement of bioreactors in the practical context of oil-spill accident recovery.

ECMP (Electro-Chemical Mechanical Polishing) presents high removal rate, low polishing pressure and good polished surface because the action of electrochemistry accelerates copper dissolution. It is considered to be a most promising novel Cu planarization process to replace traditional CMP (Chemical Mechanical Polishing). However, the micro asperity heights of coarse surface are often too small compared to the distance between anode and cathode, so the asperities are difficult to be selectively removed. In this paper, high dielectric constant abrasives were used in ECMP to solve this problem. High dielectric constant abrasives can improve the distribution of electric field, amplify the gradient of electric field and enhance the ability of selective removal. Based on the results of experiments, rutile TiO2, as one of high dielectric constant abrasives, is better than SiO2 and anatase TiO2 in ECMP process. The material removal rate of electrolyte containing rutile TiO2 is 0.078mg/min, and the surface roughness is Ra18.2nm.

Vascular stem/progenitor cells (VSCs) are an important source of all types of vascular cells needed to build, maintain, repair, and remodel blood vessels. VSCs, therefore, play critical roles in the development, normal physiology, and pathophysiology of numerous diseases. There are four major types of VSCs, including endothelial progenitor cells (EPCs), smooth muscle progenitor cells (SMPCs), pericytes, and mesenchymal stem cells (MSCs). VSCs can be found in bone marrow, circulating blood, vessel walls, and other extravascular tissues. During the past two decades, considerable progress has been achieved in the understanding of the derivation, surface markers, and differentiation of VSCs. Yet, the mechanisms regulating their functions and maintenance under normal and pathological conditions, such as in eye diseases, remain to be further elucidated. Owing to the essential roles of blood vessels in human tissues and organs, understanding the functional properties and the underlying molecular basis of VSCs is of critical importance for both basic and translational research.

Depression, a pervasive global mental disorder, profoundly impacts daily lives. Despite numerous deep learning studies focused on depression detection through speech analysis, the shortage of annotated bulk samples hampers the development of effective models. In response to this challenge, our research introduces a transfer learning approach for detecting depression in speech, aiming to overcome constraints imposed by limited resources. In the context of feature representation, we obtain depression-related features by fine-tuning wav2vec 2.0. By integrating 1D-CNN and attention pooling structures, we generate advanced features at the segment level, thereby enhancing the model's capability to capture temporal relationships within audio frames. In the realm of prediction results, we integrate LSTM and self-attention mechanisms. This incorporation assigns greater weights to segments associated with depression, thereby augmenting the model's discernment of depression-related information. The experimental results indicate that our model has achieved impressive F1 scores, reaching 79% on the DAIC-WOZ dataset and 90.53% on the CMDC dataset. It outperforms recent baseline models in the field of speech-based depression detection. This provides a promising solution for effective depression detection in low-resource environments.