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A space laser communication acquisition, pointing and tracking ( APT) system based on the beacon laser is designed without prior information. And then, a new target scanning method and a pointing and tracking algorithm are proposed. The target scanning mode is the round-trip triangular wave scanning, and it means that scanning track of the PAN-TILT platform follows the triangular wave repeatedly. For the pointing and tracking algorithm, the beacon laser is used as the auxiliary aiming light source. The position of the beacon laser in the viewfield of the complementary metal oxide semiconductor (CMOS) camera is calculated by the centroid algorithm. In order to realize the target tracking, the joint control method of the angle control and the angular velocity control is used. The simulation and experimental results show that the APT system can achieve full coverage scanning in the scanning area and capture the target in one scanning cycle successfully. After capturing the PAN-TILT platform, the pointing and tracking algorithm can track the PAN-TILT platform quickly and accurately, and the tracking accuracy is up to 0. 22 mrad. [ABSTRACT FROM AUTHOR]

The porous scaffold – a substitute for artificial bone – is vital to bone defect repair and bone tissue regeneration in tissue engineering. In consideration of the limitations of few existing design methods, the significant difference between the internal pore structure of porous scaffolds and natural bone microstructure, and the low controllability of design methods. Based on Voronoi-Tessellation (VT) and random function theory, this paper proposed a design method with controllable pore density, adjustable pore shape and size, and heterogeneous pore distribution. The stress change law of porous scaffolds under compression was analyzed using finite element simulation experiments; the relationship between the porosity and the structural strength of porous scaffolds was obtained. Furthermore, the anisotropy of porous scaffolds was studied, and the change law of the macroscopic equivalent elastic modulus with the change in porosity of porous scaffolds was acquired. Under the same porosity, the mechanical properties of the porous scaffold with a uniform pore distribution and the porous scaffold designed in this paper were analyzed and compared; the damage extension laws of two different porous scaffolds were obtained. The results demonstrate that the design method proposed in this paper has high controllability, and the parametric modeling process is both random and controllable. The internal pore structures of porous scaffolds generated by the design method are closer to the microstructure of natural bone tissue – the structural strength satisfies the requirements of artificial implants. [ABSTRACT FROM AUTHOR]

Purpose: Significant antibiotic overuse due to prolonged antibiotic duration has not draw enough attention in developing countries with high antibiotic consumption. We aimed to describe the current status of prolonged early antibiotic duration in very-low-birth-weight (VLBW) infants in a large regional multicenter cohort in China. Patients and Methods: Institution-based prospective cohort study was conducted in all VLBW infants admitted to 16 Grade A tertiary hospitals between January 1, 2019 and December 31, 2020. Early antibiotic use was defined as antibiotic initiation within the first 3 days of life. Prolonged early antibiotic course was defined as early antibiotic initiation for more than 7 days in infants with early-onset sepsis (EOS) or more than 3 days in infants with unlikely EOS. Antibiotic use was described as days of therapy (DOT) per 1000 patient days (PD). Results: Among 1684 eligible VLBW infants, 1544 (91.7%) infants were prescribed with prolonged early antibiotic course, including 618 infants with EOS and 926 infants with unlikely EOS. The median duration of early antibiotic course was 13 (IQR 8;20) days, with 78.0% of courses > 7 days and 43.6% of courses > 14 days. Total early antibiotic use was 408.3DOT/1000Pd, of which prolonged antibiotic courses accounted for 98.2% of all antibiotic use days. More than three antibiotics used, escalation antibiotic therapy, antibiotics for special use and the use of third generation cephalosporins and carbapenems were significantly common in prolonged courses compared to short courses in both infants with EOS and unlikely EOS group (P< 0.05). Conclusion: A large proportion of VLBW infants had excessively prolonged early antibiotic durations in the regional multicenter in China. Timely discontinuation of antibiotics in VLBW infants according to standardized guidelines and limit on the use of third-generation cephalosporins and carbapenems may be key drivers in reducing the antibiotic overuse in developing countries like ours. [ABSTRACT FROM AUTHOR]

Delineation of contaminated soils is important for their remediation; however, reliable and efficient methods remain lacking. In this study, a contaminated site around an abandoned refuelling station in Southeastern China was investigated using resistivity piezocone penetration (RCPTU) and membrane interface probe (MIP) tests to evaluate the spatial distribution of organic contaminants. Various influences on the MIP results were analyzed, such as contaminant concentrations, the soil–groundwater interface and soil properties. Based on RCPTU and sampling results, MIP data were quantitatively evaluated in terms of relative percentage differences. Results from a photoionization detector (PID) and flame ionization detector (FID) were found to overestimate and underestimate the total petroleum hydrocarbon concentrations, respectively. In general, the PID was slightly more accurate than FID. Maps of regional contaminant concentrations were derived from geostatistical analysis of MIP data and were compared with contaminant concentrations measured in soil samples in the laboratory. This paper provides a method for interpreting MIP data with consideration of the influence of soil properties. It demonstrates the effectiveness of using MIP to determine contaminant distributions and increase the efficiency of site remediation programs. [ABSTRACT FROM AUTHOR]

• Summarize separation mechanisms and introduce several research techniques for hydrogen isotope separation. • Outline the recent advances in MOFs in the field of hydrogen isotope separation from the perspective of the separation mechanisms. • Summarize obstacles facing the application of MOFs in hydrogen isotopes separation, and discuss changes and prospects for future applications. In the face of escalating global energy demands, deuterium (D 2) is receiving increasing attention as a clean and efficient energy source. However, the challenge of separating deuterium from hydrogen (H 2) arises due to their considerable physical and chemical similarities. The use of porous materials to separate D 2 /H 2 , which has either high separation efficiency or ideal D 2 capacity and even approaches a good balance of efficiency and capacity in the case of some advanced porous materials, is one of the most promising alternative technologies for hydrogen isotope separation. Metal-organic framework (MOF) materials, with their diverse structures, highly adjustable pore channels, and surface functionality, offer tremendous potential in the field of D 2 /H 2 separation. In this review, we systematically summarize the research progress of MOFs in D 2 /H 2 separation and discuss their advantages, challenges, and future directions from the perspectives of separation mechanisms and separation technology. [ABSTRACT FROM AUTHOR]

Objective: This study explores the potential role of a highly selective caspase-1 inhibitor, VX-765, on extracellular matrix (ECM) accumulation and inflammation in diabetic nephropathy (DN) and the underlying mechanisms. Methods: DN rats, induced via high-fat diet/streptozotocin, were used to assess the effects of VX-765. Parallel experiments were carried out on rat mesangial cell line HBZY-1 exposed to high glucose (HG) to reveal the molecular mechanism of VX-765 in preventing DN. Survival analysis, biochemical parameters and renal oxidative stress of rats were observed, and Western blotting and immunofluorescence were evaluated. In vitro, Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX)1 silencing by RNA interference and quantitative real-time PCR (qPCR) assays were conducted in HBZY-1 cells exposed to HG levels. Key findings: In vivo, VX-765 significantly reduced the increase in urine albumin excretion and ECM accumulation. The phosphorylation of nuclear factor kappa-B (NF-κB) and the expression of pro-inflammatory cytokines IL-1β, IL-6 and tumor necrosis factor (TNF)-α were significantly down-regulated. Furthermore, the generation of reactive oxygen species (ROS), phosphorylation of NF-κB and the expression of the NOX1 gene or protein were significantly decreased in HBZY-1 with VX-765 (5 μM) treatment in vitro. Conclusions: Our results demonstrated that VX-765 exerts favourable effects on DN via the simultaneous alleviation of systemic metabolic syndrome and down-regulating the renal NOX1/ROS/NF-κB pathway, suggesting that it has therapeutic potential for DN. [ABSTRACT FROM AUTHOR]

Observational evidence from a heavy precipitation event of the 2020 extreme mei-yu season is presented here to reveal a symbiotic relationship between mei-yu rainfall and the morphology of the mei-yu front. The two influence each other through dynamical and thermodynamic feedbacks and evolve in a coherent way to generate cyclic behaviors. Specifically, an intense and band-shaped mei-yu front leads to symmetrical instability in the lower atmospheric layer and convective instability in the middle atmospheric layer, forming a rainband along the front. The mei-yu front and its associated instability subsequently weaken as a result of rainfall, and the front is bent by the process of tilting frontolysis. Deep convective instability in the middle and lower layers develops in the warm, humid prefrontal area, and triggers isolated heavy rainfall replacing the original rainband south of the bent front. This warm sector precipitation then strengthens the front through tilting and diabatic heating frontogenesis. A stronger front recovers its initial band shape, and the associated rainfall also resumes the form of a rainband along the front. Analyses of potential energy associated with instability, water vapor convergence, and cross-frontal circulation are carried out to illustrate key processes of this mei-yu front–rainfall cycle. The implications of this symbiotic relationship for simulating and predicting extreme rainfall associated with mei-yu fronts are presented. [ABSTRACT FROM AUTHOR]