Optimization of leaf area index measurement method and correction of green plot ratio formula based on regional plant characteristics-a study in Chongqing, China.

The quantification of green space green plot ratio (GPR) is mostly based on estimation formulas, and the leaf area index (LAI) estimation values in these estimation formulas have not been well verified by measured LAI values, resulting in errors and uncertainties in GPR quantification results. This study aims to address this gap by measuring the LAI of 113 regional plants in Chongqing, China, following a standardized measurement path for digital hemispherical photography (DHP). The results indicate that the optimal relative exposure value (REV) was - 1 under overcast conditions and - 2 under sunny and cloudy conditions. Among the threshold algorithms for hemispherical images, the Intermodes algorithm in ImageJ was the best. The LAI of regional plants is highest in summer, followed by spring and autumn, and lowest in winter. Tree height (h) and crown width (w) are key factors affecting LAI, but the LAI also varies with plant species. Overall, the LAI of evergreen trees is higher than that of deciduous trees. The LAI of evergreen trees and shrubs with a height shorter than 5 m is the largest, and that of deciduous trees and shrubs with a crown width larger than 8 m is the largest. The study further verified that the existing GPR estimation formula exhibited large errors in Chongqing, while there was a strong correlation (R2 = 0.973) between the GPR estimation value and the measured value. A conversion formula was developed to reduce estimation biases, and the corrected formula is capable of estimating GPR values more accurately when actual LAI measurements are insufficient. Overall, this study verifies the significance of measuring localized LAI values, promotes the understanding of LAI suitability for GPR calculations, and provides an empirical formula for GPR estimation in Chongqing, China.

Stretchable Thermoelectric Fibers with Three-Dimensional Interconnected Porous Network for Low-Grade Body Heat Energy Harvesting.

Electricity generation from body heat has garnered significant interest as a sustainable power source for wearable bioelectronics. In this work, we report stretchable n-type thermoelectric fibers based on the hybrid of Ti3C2Tx MXene nanoflakes and polyurethane (MP) through a wet-spinning process. The proposed fibers are designed with a 3D interconnected porous network to achieve satisfactory electrical conductivity (σ), thermal conductivity (κ), and stretchability simultaneously. We systematically optimize the thermoelectric and mechanical traits of the MP fibers and the MP-60 (with 60 wt % MXene content) exhibits a high σ of 1.25 × 103 S m-1, an n-type Seebeck coefficient of -8.3 µV K-1, and a notably low κ of 0.19 W m-1 K-1. Additionally, the MP-60 fibers possess great stretchability and mechanical strength with a tensile strain of 434% and a breaking stress of 11.8 MPa. Toward practical application, a textile thermoelectric generator is constructed based on the MP-60 fibers and achieves a voltage of 3.6 mV with a temperature gradient between the body skin and ambient environment, highlighting the enormous potential of low-grade body heat energy harvesting.

[Design and application of an extension tube for ventilator pipeline].

At present, the extension tube of the ventilator, a long corrugated tube used in clinical practice, needs to be disconnected from the endotracheal tube when performing open sputum suction. Under positive pressure, the condensed water containing pathogenic microorganisms in the ventilator will be splashed. Some will form aerosol suspended in the air, pollute the air, increase the risk of cross-infection and operator pollution, while the ventilator will emit a corresponding alarm sound, resulting in noise pollution. Based on the above factors, a ventilator pipeline extension tube was designed by the medical staff of department of critical care medicine of the Eighth Medical Center of People's Liberation Army General Hospital and department of critical care medicine of Beijing Friendship Hospital of Capital Medical University, and was obtained the National Utility Model Patent of China (ZL 2020 2 1476518.X). The device consists of the main pipe, first pipe sleeve, second pipe sleeve, valve body, joystick, axial sleeve, etc., which can not only effectively avoid air pollution and reduce the risk of cross-infection, but also reduce noise pollution and the negative impact of loud noise on patients and medical staff.

Reduced mitochondrial size in hippocampus and psychiatric behavioral changes in the mutant mice with homologous mutation of Timm8a1-I23fs49X.

Background: Deafness-dystonia-optic neuronopathy (DDON) syndrome, a condition that predominantly affects males, is caused by mutations in translocase of mitochondrial inner membrane 8A (TIMM8A)/deafness dystonia protein 1 (DDP1) gene and characterized by progressive deafness coupled with other neurological abnormalities. In a previous study, we demonstrated the phenotype of male mice carrying the hemizygous mutation of Timm8a1-I23fs49X. In a follow-up to that study, this study aimed to observe the behavioral changes in the female mutant (MUT) mice with homologous mutation of Timm8a1 and to elucidate the underlying mechanism for the behavioral changes. Materials and methods: Histological analysis, transmission electron microscopy (EM), Western blotting, hearing measurement by auditory brainstem response (ABR), and behavioral observation were compared between the MUT mice and wild-type (WT) littermates. Results: The weight of the female MUT mice was less than that of the WT mice. Among MUT mice, both male and female mice showed hearing impairment, anxiety-like behavior by the elevated plus maze test, and cognitive deficit by the Morris water maze test. Furthermore, the female MUT mice exhibited coordination problems in the balance beam test. Although the general neuronal loss was not found in the hippocampus of the MUT genotype, EM assessment indicated that the mitochondrial size showing as aspect ratio and form factor in the hippocampus of the MUT strain was significantly reduced compared to that in the WT genotype. More importantly, this phenomenon was correlated with the upregulation of translation of mitochondrial fission process protein 1(Mtfp1)/mitochondrial 18 kDa protein (Mtp18), a key fission factor that is a positive regulator of mitochondrial fission and mitochondrial size. Interestingly, significant reductions in the size of the uterus and ovaries were noted in the female MUT mice, which contributed to significantly lower fertility in the MUT mice. Conclusion: Together, a homologous mutation in the Timm8a1 gene caused the hearing impairment and psychiatric behavioral changes in the MUT mice; the latter phenotype might be related to a reduction in mitochondrial size regulated by MTP18.

Self-Powered Electrodeposition System for Sub-10-nm Silver Nanoparticles with High-Efficiency Antibacterial Activity.

Recently, silver nanoparticles (AgNPs) have been widely applied in sterilization due to their excellent antibacterial properties. However, AgNPs require rigorous storage conditions because their antibacterial performances are significantly affected by environmental conditions. Instant fabrication provides a remedy for this drawback. In this study, we propose a self-powered electrodeposition system to synthesize sub-10-nm AgNPs, consisting of a triboelectric nanogenerator (TENG) as the self-powered source, a capacitor for storing electrical energy from the TENG, and an electrochemical component for electrodeposition. The self-powered system with larger capacitance and discharging voltage tends to deliver smaller AgNPs due to the nucleation mechanism dominated by current density. Furthermore, antibacterial tests reveal that compared to direct current (DC) electrodeposition, the TENG-based electrodeposition can synthesize finer-sized AgNPs (<10 nm) with overwhelming antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (with 100% efficiency at 2 h). This work provides a new strategy for the self-powered, instant, and controllable electrodeposition of nanoparticles.

[Design of a device for preventing pollution and air pollution in the pipeline joint of the ventilator].

Ventilators are currently the most commonly used auxiliary mechanical ventilation equipment in clinical practice, and play an important role in the treatment of hypoxemia. Ventilator-associated pneumonia (VAP) is a special type of pulmonary parenchymal inflammation of nosocomial infection in patients with mechanical ventilation, which leads the increase of mortality and affects the prognosis of patients. The non-standard management of ventilator pipeline joints and the aerosol formed by bacterial condensate splashed from ventilator pipeline pollute the air, resulting in cross infection, which are the important reasons for VAP. The existing ventilator pipeline joint cap can achieve the effect of preventing pollution, but the clinical application compliance is not high. Based on the above factors, teachers, students and medical staff of the School of Public Health and Management, Guangxi University of Chinese Medicine and other units have designed a device for preventing pollution and air pollution of the ventilator pipeline joint, and obtained the national utility model patent of China (ZL 2020 2 1361981.X). The device is composed of a model lung, a mask body, a suspension part and a beam mouth part, etc. The use method is simple, and can be applied to the pollution avoidance of invasive ventilator and non-invasive ventilator pipeline joints, to reduce the occurrence of VAP in patients and the occupational exposure of medical staff.

[Design of a portable external cardiac compression device].

Cardiopulmonary resuscitation (CPR) guidelines emphasize that external chest compressions should be started as soon as possible when CPR is performed in patients with cardiac arrest. Moreover, those guidelines stress on fast and hard compressions to make the chest fully rebound and minimize non-pressing time. Current mechanical recovery device has several problems such as displacement of the pressing position, high price, difficult to move, and easy dislocation of piston. Because of the physical loss of high-intensity unarmed CPR, the depth and frequency of external chest compression will decrease with the extension of CPR time, leading to CPR failure. Besides, there are other problems caused by non-professional staff, such as the deviation of compression position, the inaccuracy of compression depth and the unsatisfactory rebound of the chest wall. Based on the above factors, the medical staff from the intensive care unit of the Eighth Medical Center of the Chinese People's Liberation Army General Hospital designed a portable external chest cardiac compressor based on international CPR guidelines which obtained the National Utility Model Patent of China (ZL 2018 2 1173254.3). The portable external chest cardiac compressor is composed of a positioning sucker, elastic body, mounting shell, and pressing components. Rapid and accurate compression positioning, visible compression depth and full chest rebound can be achieved. This device is mobile, easy to operate, and suitable for a broad crowd and various occasions.