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CO2-driven limnic eruptions are lethal phenomena that occur in lakes with aqueous CO2 solutions that become supersaturated. The exsolution of massive CO2 dissolved in the water can happen in a very short time, possibly leading to a natural disaster as happened in the Lake Nyos (Cameroon, Africa) in 1986. More than 1700 people died. In recent years, with the utilization of the technology of CO2 sequestration in brines in geological reservoirs, there are possibilities of the CO2-brine leakage. The brine may stay in the near surface water leading to the potential of an eruption. In this experimental study, measurements have been carried out to investigate the degassing processes of CO2 solutions under different depressurizing conditions. Based on the experimental data and using the ImagePro Plus® to process the recorded images, two correlations have been obtained: (1) the relationship between the supersaturation (${\Delta }P$) required for degassing and the initial pressure; (2) the relationship between the time delay (${\Delta }t$) corresponding to bubble formation and the initial pressure. Variations of key quantities (void fraction, number of bubbles, and average diameter of bubbles) over time have been analyzed. In addition, the void fractions measured in two different depressurizing ways have been compared. The experimental data and correlations obtained in this study are useful in establishing transient fluid dynamic models for simulating CO2-driven eruptions.

Bi12TiO20–BaTiO3 bulk composite ceramics prepared by sintering a mixture of presynthesized BaTiO3 and Bi12TiO20 particles around the melting point of Bi12TiO20 could exhibit direct as well as inverse piezoelectricity without electrical polarization. To prevent the permeation of melting Bi12TiO20 into a substrate and thus increase the composition gradient, samples were sintered on an Al2O3 (0001) single crystal substrate instead of an Al2O3 ceramic substrate. In this study, the Al2O3 single crystal substrate sintering method was surprisingly found to be an effective method to improve the piezoelectric performance of Bi12TiO20–BaTiO3 ceramics. These samples showed an enhanced piezoelectric strain coefficient (d33) by 80% compared to samples sintered on Al2O3 ceramics. Moreover, the d33 value remains nearly identical over the entire surface. Combining the results of XRD, EDS, XPS, ICP and Raman spectroscopy, the improved piezoelectricity might be because of the alignment of distorted BiO5 polyhedra in the amorphous Bi12TiO20 phase caused by the composition gradient. These results offer a method to enhance the piezoelectric properties of Bi12TiO20-based ceramics and will inspire further research to develop Bi12TiO20-based ceramics suitable for practical use. [ABSTRACT FROM AUTHOR]

Background National treatment guidelines of China evolving necessitates population-level surveillance of transmitted drug resistance (TDR) to inform or update HIV treatment strategies. Methods We analyzed the demographic, clinical, and virologic data obtained from people with HIV (PWH) residing in 31 provinces of China who were newly diagnosed between 2018 and 2023. Evidence of TDR was defined by the World Health Organization list for surveillance of drug resistance mutations. Results Among the 22 124 PWH with protease and reverse transcriptase sequences, 965 (4.36%; 95% CI, 4.1–4.63) had at least 1 TDR mutation. The most frequent TDR mutations were nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.39%; 95% CI, 2.19%–2.59%), followed by nucleoside reverse transcriptase inhibitor mutations(1.35%; 95% CI, 1.2%–1.5%) and protease inhibitor mutations (1.12%; 95% CI,.98%–1.26%). The overall protease and reverse transcriptase TDR increased significantly from 4.05% (95% CI, 3.61%–4.52%) in 2018 to 5.39% (95% CI, 4.33%–6.57%) in 2023. A low level of integrase strand transfer inhibitor TDR was detected in 9 (0.21%; 95% CI,.1%–.38%) of 4205 PWH. Conclusions Presently, the continued use of NNRTI-based first-line antiretroviral therapy regimen for HIV treatment has been justified. [ABSTRACT FROM AUTHOR]

Background In 2016, China has implemented the World Health Organization's "treat all" policy. We aimed to assess the impact of significant improvements in the 95-95-95 targets on population-level human immunodeficiency virus (HIV) transmission dynamics and incidence. Methods We focused on 3 steps of the HIV care continuum: diagnosed, on antiretroviral therapy, and achieving viral suppression. The molecular transmission clusters were inferred using HIV-TRACE. New HIV infections were estimated using the incidence method in the European Centre for Disease Prevention and Control HIV Modelling Tool. Results Between 2004 and 2023, the national HIV epidemiology database recorded 2.99 billion person-times of HIV tests and identified 1 976 878 new diagnoses. We noted a roughly "inverted-V" curve in the clustering frequency, with the peak recorded in 2014 (67.1% [95% confidence interval, 63.7%–70.5%]), concurrent with a significant improvement in the 95-95-95 targets from 10-13-<71 in 2005 to 84-93-97 in 2022. Furthermore, we observed a parabolic curve for a new infection with the vertex occurring in 2010. Conclusions In general, it was suggested that the improvements in the 95-95-95 targets were accompanied by a reduction in both the population-level HIV transmission rate and incidence. Thus, China should allocate more effort to the first "95" target to achieve a balanced 95-95-95 target. [ABSTRACT FROM AUTHOR]

The unique recombinant form (URF) of HIV is formed by multiple subtypes which are cocirculating in some area, and the number of HIV recombinants is on the increase worldwide. In this study, we identified a URF named 2019638, composed of CRF01_AE and subtype B, in a man who has sex with men in Qinhuangdao, Hebei province, China. The near-full-length genome (NFLG) sequence was confirmed to be a novel URF. Within this NFLG, two CRF01_AE fragments were inserted into the pol and vif regions, respectively, using subtype B as the backbone. Moreover, the presence of the V106M and V179D point mutations in the reverse transcriptase (RT) region rendered the high-level resistance to efavirenz and nevirapine and intermediate resistance to doravirine. Our findings suggest that the HIV epidemic is evolving toward a high degree of recombination, and we need to continuously monitor HIV genetic diversity to control the further development of the AIDS epidemic. [ABSTRACT FROM AUTHOR]

The thermodynamic analysis of an increasing-pressure endothermic power cycle (IPEPC) integrated with closed-loop geothermal energy extraction (CLGEE) in a geothermal well at a depth from 2 km to 5 km has been carried out in this study. Using CLGEE can avoid some typical problems associated with traditional EGS technology, such as water contamination and seismic-induced risk. Simultaneous optimization has been conducted for the structural parameters of the downhole heat exchanger (DHE), the CO2 mixture working fluid type, and the IPEPC operating parameters. The CO2-R32 mixture has been selected as the optimal working fluid for the IPEPC based on the highest net power output obtained. It has been found that, when the DHE length is 4 km, the thermosiphon effect is capable of compensating for 53.8% of the pump power consumption. As long as the DHE inlet pressure is higher than the critical pressure, a lower DHE inlet pressure results in more power production. The power generation performance of the IPEPC has been compared with that of the organic Rankine cycle (ORC), trans-critical carbon dioxide cycle (t-CO2), and single-flash (SF) systems. The comparison shows that the IPEPC has more net power output than other systems in the case that the DHE length is less than 3 km, along with a DHE outer diameter of 0.155 m. When the DHE outer diameter is increased to 0.22 m, the IPEPC has the highest net power output for the DHE length ranging from 2 km to 5 km. The application scopes obtained in this study for different power generation systems are of engineering-guiding significance for geothermal industries. [ABSTRACT FROM AUTHOR]