As a highly efficient thermodynamic cycle formed by pure natural fluid and using aerothermal energy, transcritical CO2 technology has huge advantages in terms of energy consumption, equivalent carbon ...content and environmental benefits, and is an important technological means for global carbon neutrality and renewable energy structure transformation. After reviewing the development history of refrigerants and the basic principle of transcritical CO2 technology, the technical characteristics, research status and development trend of the transcritical CO2 cooling/heating technology in the fields of vehicle air conditioning, building heating, hot water supply, drying industry, commercial cold chain and other fields are comprehensively summarized in details. The main problems in the development of transcritical CO2 technology was summarized regarding different applications with their unique operating conditions and requirements, while corresponding structural modification and thermodynamic parameter optimization schemes have been briefly summarized. As results, it has been proved that CO2 refrigerant has become one of the most important solutions in various applications, and this historical trend has been almost irreversible. Therefore, the future development of the transcritical CO2 technologies, including the system intelligentization and expansion work recovery techniques such as expander, ejector and vortex tube, were carefully analyzed. In summary, the explosive development of the transcritical CO2 technology will be significant for mitigating the contemporary environmental challenges and respecting the regulations on the progressive ban of hydrofluorocarbons (HFCs), so relevant contents are detailed in this paper for providing reference for its further engineering and industrialization.
•The relationship between CO2 refrigerant and the global carbon neutralization was revealed.•The current states of transcritical CO2 technique was analyzed from views of various applications.•The main problems in the development of transcritical CO2 technology was summarized.•Solutions to different constrains were comprehensively summarized in various applications.•The future development direction of the transcritical CO2 technology was carefully pointed out.
This study investigated the underlying mechanism of long noncoding RNA (lncRNA) small nucleolar RNA host gene 20 (SNHG20) in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). LncRNA ...SNHG20 and PTEN expression levels were detected by quantitative real-time polymerase chain reaction and western blot. The proliferation of HCC cells was measured by MTT assay, and the apoptosis of HCC cells was measured by flow cytometry analysis. SNHG20 expression level and HBx protein level were upregulated in HBV(+) group than that of HBV(-) group, whereas PTEN protein level was downregulated in HBV(+) group. Besides, SNHG20 was highly expressed in HBV(+) HCC cells than in HBV(-) HCC cells. SNHG20 expression level was positively associated with HBV x protein (HBx) in HCC cells, and HBx-SNHG20 involved in regulating the proliferation and apoptosis of HCC cells. Moreover, SNHG20 was confirmed to interact with PTEN, which negatively regulated PTEN protein level. Finally, we proved HBx-SNHG20-PTEN signalling pathway involved in the regulation of HCC cell proliferation and apoptosis. In vivo experiments showed SNHG20 knockdown inhibited tumour growth of HBV(+) HCC. HBx promoted the proliferation of HCC cell and reduced the apoptosis of HCC cells through the SNHG20/PTEN signalling pathway.
Adenosine-to-inosine (A-to-I) RNA editing regulates miRNA biogenesis and function. To date, fewer than 160 miRNA editing sites have been identified. Here, we present a quantitative atlas of miRNA ...A-to-I editing through the profiling of 201 pri-miRNA samples and 4694 mature miRNA samples in human, mouse, and
We identified 4162 sites present in ∼80% of the pri-miRNAs and 574 sites in mature miRNAs. miRNA editing is prevalent in many tissue types in human. However, high-level editing is mostly found in neuronal tissues in mouse and
Interestingly, the edited miRNAs in neuronal and non-neuronal tissues in human gain two distinct sets of new targets, which are significantly associated with cognitive and organ developmental functions, respectively. Furthermore, we reveal that miRNA editing profoundly affects asymmetric strand selection. Altogether, these data provide insight into the impact of RNA editing on miRNA biology and suggest that miRNA editing has recently gained non-neuronal functions in human.
Ischemia-reperfusion (IR) injury is a major cause of clinical emergencies during and after surgical procedures. Propofol protects the heart from cardiovascular IR injury by inhibiting autophagy. ...MicroRNAs (miRNAs) participate in anesthetic-regulated cardiovascular injury. MiR-20b-5p targets unc-51-like autophagy activating kinase 1 (ULK1). Its role in propofol-modulated cardiovascular IR injury remains unclear, however. In this study, we used an
in vitro
model of hypoxia-reoxygenation (HR)-induced injury to human umbilical vein endothelial cells (HUVECs) to determine the protective effect of miR-20b-5p in cells preconditioned with propofol. We found that miR-20b-5p was significantly higher and ULK1 was lower in propofol-preconditioned HUVECs with HR injury than in HUVECs with HR injury only. Additionally, miR-20b-5p overexpression increased cell viability and repressed autophagy and apoptosis more in propofol-preconditioned HUVECs with HR injury than in HUVECs with HR injury only. A luciferase reporter assay confirmed the target reaction between miR-20b-5p and ULK1. Overexpression of ULK1 restrained the protective effect of miR-20b-5p in propofol-preconditioned HUVECs with HR injury. In conclusion, our results indicate that propofol inhibits autophagic cell death via the miR-20b-5p-ULKI axis and that ULK1 may be a therapeutic target for cardiovascular IR injury.
•A novel combined R134a and transcritical CO2 heat pump was studied.•Ambient temperature had a large effect on the system performance.•The system offered a stable temperature hot water with a better ...performance.•The comparison results showed that the system improved the COP by up to 22%.
In this paper, a novel combined R134a and transcritical CO2 system was studied theoretically and experimentally for space heating. Experimental results showed that the ambient and space heating temperatures substantially affected the system performance. At the heating requirement with 50 °C in feed water temperature and 70 °C in supply water temperature, the heating capacity and coefficient of performance (COP) increased by 32.6% and 18.2%, respectively, as the ambient temperature increased from −20 °C to 0 °C. The system COP increased by up to 15% at fixed ambient condition as the feed and supply water temperatures decreased from 50 °C/70 °C to 40 °C/50 °C. A mathematical model was also developed and validated using experimental data. The model was used to investigate the performance improvement of the combined system in comparison to the standard transcritical CO2 system. The comparison results showed that the combined system improved the COP by up to 22%.
Orally administered crocin rapidly and efficiently rescues depressive-like behaviors in depression models; however, crocin levels in the circulatory and central nervous systems are rather low. The ...underlying mechanism responsible for the inconsistency between pharmacokinetics and pharmacodynamics is unknown. To identify the active metabolites and clarify the underlying mechanisms, the pharmacokinetics and metabolic effects of the gut flora and hepatic and intestinal microsomes on crocin were examined, and the pharmacodynamics of crocin and its major metabolite, crocetin, were also evaluated in both normal and pseudo germ-free mice subjected to chronic social defeat stress. The results showed that oral administration of 300 mg/kg crocin significantly improved the depression-like behaviors of chronic social defeat stress mice, although the levels of crocin in the circulatory system were rather low (Cmax = 43.5 ± 8.6 μg/L; AUC = 151 ± 20.8 μg·h/L). However, the primary metabolite of crocetin was much more abundant in vivo (Cmax = 4662.5 ± 586.1 μg/L; AUC = 33,451.9 ± 3323.6 μg·h/L). Orally administered crocin was primarily metabolized into crocetin by the gut flora instead of hepatic or intestinal microsomal enzymes, and less than 10% of crocin was transformed into crocetin in the liver or intestinal microsomes. Inhibition of the gut flora dramatically reduced the production of and in vivo exposure to crocetin, and the rapid antidepressant effect of crocin disappeared. Moreover, crocetin showed rapid antidepressant effects similar to those of crocin, and the effects were independent of the gut flora. In conclusion, the metabolic transformation of crocin to crocetin primarily contributes to the rapid antidepressant effects of crocin and is dependent on the gut flora.
In this paper, a new R744 heat pump system is studied. The gas cooler, evaporator, indoor heat core, and indoor gas cooler are all micro-channel heat exchangers. The R744 high pressure system adopts ...a combination of an accumulator and internal heat exchanger (ACCU/IHX). In addition, an electronic reversible regulating valve is added before the outdoor gas cooler, making the outdoor heat exchanger able to be used as a gas cooler or evaporator. The water-cooled condenser can improve the performance in the cooling or heating mode. The research contents contain the performance and optimal pressure under extreme conditions as a result of the experiments. The results show that the cooling capacity can reach 8.2 kW with a COP of 1.87, under a 40 °C external circulation intake. The cooling capacity on the battery side can reach 11 kW under an ambient temperature of 40 °C, which can provide a sufficient cooling capacity. Under an ambient temperature of −20 °C, the maximum heating capacity can reach 6.86 kW with a COP of 1.67. Under an ambient temperature of −15 °C, the heating capacity reaches 5.07 kW with a COP of 1.78, when the indoor air volume flow rate is 200 m3/h. Obviously, R744 heat pumps show a huge advantage, compared with the traditional PTC heating or R134a heat pumps at extremely low temperatures.
The emergence of multidrug-resistant tuberculosis (MDR-TB) in HIV-positive people poses a significant challenge to international efforts to eradicate tuberculosis (TB). Many studies found conflicting ...results when examining the correlation between HIV and MDR-TB. The purpose of the present investigation was to comprehensively review the literature on the association between HIV infection and MDR-TB in order to evaluate the impact of HIV on MDR-TB worldwide.
Utilizing the databases PubMed, Scopus, Google Scholar, and ScienceDirect, studies published between January 2000 and March 2023 that are eligible for meta-analysis were selected. Using the random-effects model, the aggregated odds ratio of the empirical relationship between HIV and MDR-TB was calculated, along with a confidence interval ranging from 0 to 95 %. Examining the asymmetry of the funnel plot and utilizing Egger's and Begg's test, the possibility of publication bias was investigated. The extent of heterogeneity was determined using the I2 statistics.
Through a database search, we identified 1214 studies, from which we ultimately selected 15 studies involving 9667 patients. The odds ratio of 2.78 (95 % confidence interval: 1.07–7.20) between HIV/AIDS and MDR-TB indicates a significant positive correlation. Tau 2 = 3.46, chi 2 = 1440.46, df = 14, I2 = 99.0 %, z = 2.10, and p 0.05 indicate that there is substantial heterogeneity among pooled studies. Since I2 is 99 % (>50 %), a random effect model was employed. The percentage of multidrug-resistant HIV-positive patients across all included studies follows a normal distribution, as shown by a Box and whisker plot with a symmetric skewness and a mesokurtic tail and a scatter plot with a significant R2 value below 1 R2 = 0.2476 showed the positive correlation between multidrug resistance and HIV infection.
HIV infection increases MDR-TB risk, and the preceding pooled analysis showed an increased risk trend. Thus, MDR-TB, especially in HIV-positive patients, requires early case detection, quality-assured bacteriology diagnosis, and an effective infection control program.
This paper presents a particle swarm tracking algorithm with improved inertia weight based on color features. The weighted color histogram is used as the target feature to reduce the contribution of ...target edge pixels in the target feature, which makes the algorithm insensitive to the target non-rigid deformation, scale variation, and rotation. Meanwhile, the influence of partial obstruction on the description of target features is reduced. The particle swarm optimization algorithm can complete the multi-peak search, which can cope well with the object occlusion tracking problem. This means that the target is located precisely where the similarity function appears multi-peak. When the particle swarm optimization algorithm is applied to the object tracking, the inertia weight adjustment mechanism has some limitations. This paper presents an improved method. The concept of particle maturity is introduced to improve the inertia weight adjustment mechanism, which could adjust the inertia weight in time according to the different states of each particle in each generation. Experimental results show that our algorithm achieves state-of-the-art performance in a wide range of scenarios.
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•Tungsten contents are high in zircons of tungsten ore-forming intrusions.•Copper contents are high in zircons of copper ore-forming intrusions.•Zircons Ce4+/Ce3+ ratios indicated ...that the Cu/Fe magmas are more oxidized than W.•Zircon represents a good indicator for distinguishing different ore compositions.
It has long been established that skarn deposits of different metals are associated with intrusions of different compositions. Intermediate-felsic granitoids in the Edong district of the Middle-Lower Yangtze Metallogenic Belt host skarn deposits with varying W-Cu-Fe proportions, yet previous whole-rock geochemical studies could not distinguish between the magmatic suites that formed the different skarn deposits. In this study, LA-ICP-MS zircon geochemical data are presented for the Ruanjiawan W skarn (60300 t WO3), Tongshankou Cu skarn (0.6 Mt Cu), Tonglushan Cu-Fe skarn (1.1 Mt Cu and 56.8 Mt Fe) and Jinshandian Fe skarn (200 Mt Fe) deposits in the Edong district. Zircons from the ore-forming intrusions of these skarn deposits are all characterized by heavy rare earth element (HREE) enrichments and light rare earth element (LREE) depletions, with positive Ce anomalies and slightly negative Eu anomalies. Tungsten contents in zircons from the W ore-forming intrusion (0.02–3.16 ppm W; avg. 1.14 ppm) are generally higher than in zircons from the Cu ore-forming intrusion (0.00–0.24 ppm W; avg. 0.03 ppm). Copper content in zircons from the Cu ore-forming intrusion is higher than in those from the W ore-forming intrusion. Fertile intrusive rocks from the four skarn deposits contain zircons with high calculated Ce4+/Ce3+ ratios (Ruanjiawan: 71.7; Tongshankou: 207.5; Tonglushan: 263.6; Jinshandian: 189.0. Fluorine content of the Ruanjiawan intrusion is higher than the Tonglushan and Jinshandian intrusions, followed by the Tongshankou intrusion. Chlorine contents show the opposite trend. We propose that the different source regions for the ore-fertile intrusions is the critical factor that controls the metal content, oxygen fugacity and volatile components. Our studies suggest that zircon geochemistry is a good indicator to distinguish tungsten causative intrusions from copper- and iron ore related intrusions (i.e. W content ≧ 1.14 ppm and Ce4+/Ce3+ ratios ≦ 207.5).
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