Antenna array-based metasurface for multi-scenario wide-angle polarization-insensitive radar cross section reduction.

In this paper a novel antenna array-based metasurface design method for wide-angle and polarization-insensitive radar cross section (RCS) reduction has been proposed, which can be applied to a variety of RCS reduction scenarios. The proposed metasurface subarray design employs a dual-element antenna array in which the two ports of each element are connected through a Wilkinson power divider, and meanwhile, two power dividers are connected through a microstrip line with a lumped resistor. The use of dual-polarized wide-beam antennas enables the metasurface array to respond to arbitrarily polarized as well as wide-angle obliquely incident electromagnetic waves. A portion of the electromagnetic waves received will be absorbed by the lumped resistor and converted into heat, while the remaining portion will be canceled in the space, achieving the low RCS characteristic. The proof-of-concept experiments have been conducted in several application scenarios for RCS reduction, including a metasurface array integrated with a microstrip antenna, a densely distributed dual-element metasurface array, and a randomly distributed dual-element metasurface array. Simulated and measured results confirm that the proposed method opens up a new avenue for more flexible and versatile RCS reduction devices and systems.

Comparison of local excision and total mesorectal excision for rectal cancer: Systematic review and meta-analysis of randomised controlled trial.

To report the first and largest systematic review and meta-analysis of radomised controlled trials (RCTs) to compare the efficacy and safety of transanal endoscopic microsurgery (TEM) and total mesorectal excision (TME) for rectal cancer for perioperative and oncological outcomes. Methods: We conducted a systematic literature retrieval via PubMed, Embase, Web of Science, and Cochrane until December 2022 for RCTs which evaluated the efficacy and/or safety between TEM and TME for rectal cancer. Outcomes included operative time, blood loss, transfusion rates, hospital stay, complication rates, recurrence rates, and mortality. Results: A total of 5 RCTs involving 545 patients (272 TEM versus 273 TME) were included for the meta-analysis. There were no significant differences between the two groups for age, gender, and distance from lower border of tumor to anal verge. Meta-analysis found that the TEM group was significantly favorable than the TME group for blood loss (WMD: 172.01; 95 % CI: 212.78, -131.24; P < 0.00001), hospital stay (WMD: 2.58; 95 % CI: 3.01, -2.16; P < 0.00001), operative time (WMD: 81.86; 95 % CI: 87.51, -76.21; P < 0.00001) and transfusion rates (RR: 0.05; 95 % CI: 0.01, 0.38; P = 0.004). The complication rates (RR: 0.60; 95 % CI: 0.32, 1.11; P = 0.10), recurrence rates (RR: 1.10; 95 % CI: 0.66, 1.83; P = 0.72), and mortality (RR: 1.23; 95 % CI: 0.67, 2.26; P = 0.51) were similar in the two groups. Conclusions: TEM was an effective and safe approach with advantages in perioperative outcomes compared with TME approach. Caution should be exercised in interpreting the differences in surgical complications between TEM and TME group due to significant heterogeneity and instability.

Enzymatic browning and polyphenol oxidase control strategies.

Significant amounts of fresh and fresh-cut fruits and vegetables are wasted every year due to enzymatic browning. Polyphenol oxidase (PPO) is the key enzyme involved in the enzymatic browning. In the past decades, various methods have been developed to inhibit browning of various fresh produce items. However, for most fresh horticultural produce, ideal measures accepted by industries and consumers are still scarce. This review provides up-to-date knowledge of browning control technologies, including physical methods, chemical methods such as natural inhibitors, molecular biotechnology, and nanotechnology. In addition, we propose some ideas to improve the efficacies of these strategies with fewer side effects. To better inhibit tissue browning, new research directions are also discussed, for example, regulation of PPO substrate techniques.

Maintaining the quality of postharvest broccoli by inhibiting ethylene accumulation using diacetyl.

Broccoli (Brassica oleracea L. var. Italic) is rich in nutrition. However, it is susceptible to yellowing after harvest, leading to nutritional and economic losses. In this study, diacetyl, a natural food additive compound, was selected to inhibit the yellowing of broccoli florets and maintain the nutrient quality during storage time. It was found that 20 µl L-1 diacetyl treatment for 12 h could significantly delay the yellowing and decrease the weight loss and lignin content of broccoli florets. Meanwhile, diacetyl could maintain higher contents of chlorophyll, vitamin C and flavonoids and suppress the transcript levels of chlorophyll degradation-related genes in broccoli florets. Moreover, accumulations of reactive oxygen species (ROS) were inhibited by diacetyl treatment. Under diacetyl treatment, the generation of ethylene was prevented by inhibiting the activities and related-gene expressions of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase. Based on our findings, exogenous diacetyl could be employed as a novel bioactive molecule for retarding the yellowing and maintaining the quality of postharvest broccoli.

Wideband composite planar spiral antenna for generation of tunable angular momentum wave.

In this paper, a composite planar spiral antenna consisting of an eight-arm equiangular spiral antenna and eight Archimedean spiral antennas has been designed to radiate electromagnetic wave carrying tunable angular momenta in a wide band. A tunable eight-way Wilkinson power divider network is used to offer three kinds of feeding modes for the equiangular spiral antenna, and thus the composite antenna can radiate the electromagnetic waves with angular momenta of the modes l=1, 2, and 3, respectively. The Archimedean spiral is introduced to improve the gain of the composite antenna in the case of the angular momentum of l=3. By analyzing axis ratio (AR) of the proposed antenna, the generated angular momentum of l=1 is spin angular momentum (SAM), and the angular momenta of both l=2 and 3 include SAM and orbital angular momentum (OAM). Simulated and measured results are given to demonstrate good performance including tunable modes, good purity and wide band.

Neural Remodeling of the Left Atrium in Rats by Rosuvastatin Following Acute Myocardial Infarction.

OBJECTIVE: This study aims to investigate the effect of rosuvastatin on sympathetic neural remodeling of the left atrium (LA) in rats after myocardial infarction (MI). METHODS: Rats were randomly divided into a three groups: sham group, statin group, and MI group. The mRNA expression levels of the growth-associated protein-43 (GAP43) and nerve growth factor (NGF) were measured by RT-PCR. Immunohistochemistry was used to detect the distribution and density of GAP43- and NGF-positive nerves. The expression levels of these proteins were quantified by Western blot. RESULTS: Compared with the sham group, the average optical density (AOD) values of GAP43 and nerve growth factor (NGF)-positive substances in the LA in the statin and MI groups were significantly higher (P<0.01), but the AOD values in the statin group were lower than of those in the MI group (P<0.01). Furthermore, the AOD values of GAP43 and NGF positive nerves in the left stellate ganglion in the statin and MI groups were significantly higher (P<0.01), but the AOD values in the statin group were lower, when compared with the MI group (P<0.01). CONCLUSION: Rosuvastatin could effectively improve the sympathetic neural remodeling of LA in MI rats.

[Differential time attachment: optimization of the adherent time to obtain mouse bone marrow-derived endothelial progenitor cells].

The different biological functions were studied in mouse bone marrow-derived endothelial progenitor cells isolated by differential time attachment to obtain the optimal adherent time in this study. Density gradient centrifugation-isolated bone marrow mononuclear cells were seeded on the fibronectin-coated dish. The 1-day cultured unattached cells were seeded on the second dish for 2 more days. Then unattached cells in the second dish were seeded on the third dish. The cells on 3 dishes were defined as 1-day adherent cells, 3-day adherent cells and 3-day unattached cells, respectively. After 20-day culture, the biological functions, such as the percentage of biomarkers, the ability of adhesion, and the ability of forming tubes in vitro were analyzed. The results showed that the percentages of positive CD34, FLK-1, and CD34/FLK-1 expressions in 1-day attached cells were significantly increased compared to those in the 3-day adherent or unattached cells (P < 0.01), which showed the strongest adhesion ability. The expression of eNOS in 1- or 3-day adherent cells was significantly higher than that in 3-day unattached cells (P < 0.01). The expression of VEGF in 3-day adherent cells was significantly higher than that in 1-day adherent cells or 3-day unattached cells (P < 0.01). These results suggest the biological functions of 1-day adherent cells are significantly stronger than that of 3-day adherent or unattached cells. VEGF expression in 3-day adherent cells is higher than that in 1-day adherent cells or 3-day unattached cells. The expression of eNOS in 1-day adherent cells or 3-day adherent cells is higher than that in 3-day unattached cells. The optimal adherent time to obtain mouse bone marrow-derived endothelial progenitor cells is 1-3 d.

Differential time attachment: optimization of the adherent time to obtain mouse bone marrow-derived endothelial progenitor cells / 生理学报

The different biological functions were studied in mouse bone marrow-derived endothelial progenitor cells isolated by differential time attachment to obtain the optimal adherent time in this study. Density gradient centrifugation-isolated bone marrow mononuclear cells were seeded on the fibronectin-coated dish. The 1-day cultured unattached cells were seeded on the second dish for 2 more days. Then unattached cells in the second dish were seeded on the third dish. The cells on 3 dishes were defined as 1-day adherent cells, 3-day adherent cells and 3-day unattached cells, respectively. After 20-day culture, the biological functions, such as the percentage of biomarkers, the ability of adhesion, and the ability of forming tubes in vitro were analyzed. The results showed that the percentages of positive CD34, FLK-1, and CD34/FLK-1 expressions in 1-day attached cells were significantly increased compared to those in the 3-day adherent or unattached cells (P < 0.01), which showed the strongest adhesion ability. The expression of eNOS in 1- or 3-day adherent cells was significantly higher than that in 3-day unattached cells (P < 0.01). The expression of VEGF in 3-day adherent cells was significantly higher than that in 1-day adherent cells or 3-day unattached cells (P < 0.01). These results suggest the biological functions of 1-day adherent cells are significantly stronger than that of 3-day adherent or unattached cells. VEGF expression in 3-day adherent cells is higher than that in 1-day adherent cells or 3-day unattached cells. The expression of eNOS in 1-day adherent cells or 3-day adherent cells is higher than that in 3-day unattached cells. The optimal adherent time to obtain mouse bone marrow-derived endothelial progenitor cells is 1-3 d.

Effects of xuezhikang on proliferation and adhesion capacity of cultured endothelial progenitor cells: An in vitro study.

BACKGROUND: Endothelial progenitor cells (EPCs) might be useful in the management of coronary artery disease (CAD). OBJECTIVE: The aim of this study was to investigate the effects of xuezhikang, an extract of Chinese red yeast rice, on the proliferation and adhesion capacity of EPCs from the peripheral blood of patients with stable CAD. METHODS: Mononuclear cells from 20 Chinese patients (14 men, 6 women; mean [SD] age, 64.5 [2.8] years [range, 60-69 years]) were isolated using densitygradient centrifugation. After 4 days in culture, the attached cells were treated with different concentrations of xuezhikang (50, 125, 250, and 500 ng/mL; 20 samples/group), atorvastatin (10 ng/mL; n = 20), or phosphate-buffered saline (control, n = 20) for 3 days. Cells that were positive for 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine-labeled acetylated low-density lipoprotein and lectin were defined as EPCs. They were counted by 2 independent investigators in ≥4 randomly selected highpower fields per well. EPCs were then treated and adherent cells were counted by the independent investigators who were blinded to study drug administration. RESULTS: The mean (SD) number of cultured EPCs in the xuezhikang 50-, 125-, 250-, and 500-ng/mL groups (205 [28], 244 [31], 283 [42], and 334 [43] cells, respectively; all, P < 0.001) was significantly increased in a dose-dependent manner compared with the control group (167 [36] cells). The adhesion capacity of the EPCs was significantly greater in the 4 xuezhikang groups (51 [9], 62 [10], 71 [11], and 83 [12] cells; all, P < 0.001) when compared with that of the control group (41 [7] cells). Both the number of EPCs (327 [49] cells) and the number of adhesive EPCs (84 [15] cells) in the atorvastatin group were also significantly increased compared with the control group (both, P < 0.001); however, these increases were not significantly different from those in the xuezhikang 500-ng/mL group. CONCLUSIONS: Xuezhikang was associated with significantly enhanced proliferation and adhesion capacity of EPCs derived from the peripheral blood of these patients with stable CAD. These effects were not significantly different between xuezhikang and atorvastatin.

[Video-assisted thoracoscopic left sympathectomy for the treatment of congenital long QT syndrome].

OBJECTIVE: To assess the feasibility, safety and effectiveness of video-assisted thoracoscopic sympathectomy (VATS) for the treatment of congenital long QT syndrome. METHODS: Under general anaesthesia, pleural cavity was entered via two or three small incisions in the left intercostal space. The left thoracic sympathetic chain was identified and resected from T2 approximately T5. The lower one at the third of the left stellate ganglion was also resected. RESULTS: VATS resulted in a significant shortening in corrected QT intervals in three patients. The average QT interval of the four patients was 537.5 ms before VATS and 512.5 ms after VATS. The heart rate of the patients remained unchanged. There were no major peri-operative complications apart from mild ptosis of the left upper eyelid in one patient who recovered in the following days. The syndrome recurred in one patient in syncopal events in four months after VATS. CONCLUSION: VATS is a safe as well as an effective technique for the treatment of congenital long QT syndromes.

Video-assisted thoracoscopic left sympathectomy for the treatment of congenital long QT syndrome / 中华外科杂志

<p><b>OBJECTIVE</b>To assess the feasibility, safety and effectiveness of video-assisted thoracoscopic sympathectomy (VATS) for the treatment of congenital long QT syndrome.</p><p><b>METHODS</b>Under general anaesthesia, pleural cavity was entered via two or three small incisions in the left intercostal space. The left thoracic sympathetic chain was identified and resected from T2 approximately T5. The lower one at the third of the left stellate ganglion was also resected.</p><p><b>RESULTS</b>VATS resulted in a significant shortening in corrected QT intervals in three patients. The average QT interval of the four patients was 537.5 ms before VATS and 512.5 ms after VATS. The heart rate of the patients remained unchanged. There were no major peri-operative complications apart from mild ptosis of the left upper eyelid in one patient who recovered in the following days. The syndrome recurred in one patient in syncopal events in four months after VATS.</p><p><b>CONCLUSION</b>VATS is a safe as well as an effective technique for the treatment of congenital long QT syndromes.</p>