Modulation Design and Optimization for RIS-Assisted Symbiotic Radios

In reconfigurable intelligent surface (RIS)-assisted symbiotic radio (SR), the RIS acts as a secondary transmitter by modulating its information bits over the incident primary signal and simultaneously assists the primary transmission, then a cooperative receiver is used to jointly decode the primary and secondary signals. Most existing works of SR focus on using RIS to enhance the reflecting link while ignoring the ambiguity problem for the joint detection caused by the multiplication relationship of the primary and secondary signals. Particularly, in case of a blocked direct link, joint detection will suffer from severe performance loss due to the ambiguity, when using the conventional on-off keying and binary phase shift keying modulation schemes for RIS. To address this issue, we propose a novel modulation scheme for RIS-assisted SR that divides the phase-shift matrix into two components: the symbol-invariant and symbol-varying components, which are used to assist the primary transmission and carry the secondary signal, respectively. To design these two components, we focus on the detection of the composite signal formed by the primary and secondary signals, through which a problem of minimizing the bit error rate (BER) of the composite signal is formulated to improve both the BER performance of the primary and secondary ones. By solving the problem, we derive the closed-form solution of the optimal symbol-invariant and symbol-varying components, which is related to the channel strength ratio of the direct link to the reflecting link. Moreover, theoretical BER performance is analyzed. Finally, simulation results show the superiority of the proposed modulation scheme over its conventional counterpart.Comment: 16 pages,15 figure

Preparation and characterization of porous magnetic steel slag abrasives

To effectively solve the problems of environmental pollution and resource waste caused by steel slag and open up a new field of application of steel slag, the porous magnetic steel slag abrasive was prepared by combining the gas quenching process with steel slag as the main raw material. Besides, and the micro-morphology, the pore structure, the magnetic properties, the mechanical properties and the abrasive properties of steel slag abrasive were characterized by field emission scanning electron microscope, high-performance automatic mercury porosimeter, magnetometer, etc. The results show that the steel slag abrasive is monodisperse spherical, and there are disordered pores arranged in round or elliptical shape on its surface and cross section. The porosity of abrasive sample is 37% to 45%, and the pore volume is 0.18 to 0.23 mL/g. Under the action of external magnetic field, with the increase of the particle size of the abrasive sample, its hysteresis loop shifts clockwise and presents a narrow “S” type closed curve. The abrasive sample shows typical ferrous magnetism, which can effectively improve the surface quality of aluminum alloy workpiece, and the surface roughness Ra of the workpiece is reduced from 3.2 µm to 0.7 µm

The Efficacy of Composite Essential Oils against Aflatoxigenic Fungus Aspergillus flavus in Maize

The efficacy of eleven essential oils (EOs) against Aspergillus flavus NRRL 3357 was investigated. The highest antifungal activity against this aflatoxigenic fungus was exhibited by cinnamon, oregano and lemongrass, which showed low minimum inhibitory concentration (MIC) values under vapor conditions. Interactions of the three EOs were evaluated by the fractional inhibition concentration index (FICI), and the composite essential oils (CEO) showed synergistic inhibitory activities. Chemical analysis of the composite essential oils of cinnamon, oregano, and lemongrass (COL-CEO) revealed that (Z)-citral (33.44%), (E)-citral (32.88%) and carvacrol (19.84%) were the dominant components, followed by limonene (4.29%) and cinnamaldehyde (3.76%). COL-CEO not only inhibited fungal growth but also decreased aflatoxin B1 production by A. flavus. Downregulation of the relative expression of aflatoxin genes in the aflatoxin biosynthetic pathway by COL-CEO revealed its anti-aflatoxigenic mechanism. COL-CEO could also affect the colonization of A. flavus on maize grains. Therefore, COL-CEO may be considered as a potential natural antifungal agent, which could be used for the storage of maize and other grains

Effect of an upstream bulge configuration on film cooling with and without mist injection

To meet the economic requirements of power output, the increased inlet temperature of modern gas turbines is above the melting point of the material. Therefore, high-efficient cooling technology is needed to protect the blades from the hot mainstream. In this study, film cooling was investigated in a simplified channel. A bulge located upstream of the film hole was numerically investigated by analysis of the film cooling effectiveness distribution downstream of the wall. The flow distribution in the plate channel is first presented. Comparing with a case without bulge, different cases with bulge heights of 0.1d, 0.3d and 0.5d were examined with blowing ratios of 0.5 and 1.0. Cases with 1% mist injection were also included in order to obtain better cooling performance. Results show that the bulge configuration located upstream the film hole makes the cooling film more uniform, and enhanceslateral cooling effectiveness. Unlike other cases, the configuration with a 0.3d-height bulge shows a good balance in improving the downstream and lateral cooling effectiveness. Compared with the case without mist at M = 0.5, the 0.3d-height bulge with 1% mist injection increases lateral average effectiveness by 559% at x/d = 55. In addition, a reduction of the thermal stress concentration can be obtained by increasing the height of the bulge configuration

The expression of TRIAD1 and DISC1 after traumatic brain injury and its influence on NSCs

Abstract Background After cerebral injury, the proliferation and differentiation of neural stem cells are important for neural regeneration. Methods We used the SD rat to establish the traumatic brain injury model. Then, we verified molecular expression, interaction through Western blot, immunoprecipitation (IP), immunofluorescence, and other methods. All data were analyzed with Stata 8.0 statistical software. Results We showed for the first time that the interaction of TRIAD1 and DISC1 plays an important role in neural stem cell proliferation and differentiation after traumatic brain injury. In a rat model of traumatic brain injury, we found that the expression of TRIAD1 increased progressively, reached a peak at 3 to 5 days, and then decreased gradually. While the expression level of DISC1 was correlated with TRIAD1, its expression level at 3 days was significantly lower than at other time points. Immunofluorescence on frozen brain sections showed that TRIAD1 and DISC1 are co-localized in neural stem cells. Immunoprecipitation data suggested that TRIAD1 may interact with DISC1. We transfected 293T tool cells with plasmids containing truncated fragments of TRIAD1 and DISC1 and used additional IPs to reveal that these two proteins interact via specific fragments. Finally, we found that overexpressing TRIAD1 and DISC1 in primary neural stem cells, via lentiviral transfection, significantly affected the proliferation and differentiation of those neural stem cells. Conclusions Taken together, these data show that the expression of TRIAD1 and DISC1 change after traumatic brain injury and that their interaction may affect the proliferation and differentiation of neural stem cells. Our research may provide a sufficient experimental basis for finding molecular targets for neural stem cell proliferation and differentiation. Trial registration We did not report the results of a health care intervention on human participants

Efficient Asymmetric Synthesis of (<i>S</i>)-<i>N</i>-Boc-3-hydroxypiperidine by Coexpressing Ketoreductase and Glucose Dehydrogenase

(S)-N-Boc-3-hydroxypiperidine is an important intermediate of the anticancer drug ibrutinib and is mainly synthesized by the asymmetric reduction catalyzed by ketoreductase coupled with glucose dehydrogenase at present. In this study, the coexpression recombinant strains E. coli/pET28-K-rbs-G with single promoter and E. coli/pETDuet-K-G with double promoters were first constructed for the coexpression of ketoreductase and glucose dehydrogenase in the same cell. Then, the catalytic efficiency of E. coli/pET28-K-rbs-G for synthesizing (S)-N-Boc-3-hydroxypiperidine was found to be higher than that of E. coli/pETDuet-K-G due to the more balanced activity ratio and higher catalytic activity. On this basis, the catalytic conditions of E. coli/pET28-K-rbs-G were further optimized, and finally both the conversion of the reaction and the optical purity of the product were higher than 99%. In the end, the cell-free extract was proved to be a better catalyst than the whole cell with the improved catalytic efficiency of different recombinant strains. This study developed a better coexpression strategy for ketoreductase and glucose dehydrogenase by investigating the effect of activity ratios and forms of the biocatalysts on the catalytic efficiency deeply, which provided a research basis for the efficient synthesis of chiral compounds

Factors Influencing the Sample Adequacy of Ultrasound-Guided Fine-Needle Aspiration from Solid Thyroid Nodules for Liquid-Based Cytology: A Demographic, Sonographic, and Technical Perspective

Background and Objectives: To identify factors that influence the sample adequacy of solid thyroid nodules based on ultrasound-guided fine-needle aspiration (FNA) with subsequent liquid-based cytology. Materials and Methods: We retrospectively reviewed 855 patients who underwent ultrasound-guided FNA at our hospital between July 2019 and July 2020. The final analysis included 801 solid thyroid nodules in 801 patients. After reviewing the demographic data, ultrasonic features, and FNA technique-related factors, we defined 14 potential variables. For cytological results, the Bethesda categories II&ndash;VI were defined as adequate sample results. Univariate and multivariate analyses were performed to identify factors that influenced sample adequacy. Results: The adequate sample rate was 87.1%. The univariate analysis showed that four factors were related to adequate sampling in patients with thyroid FNA. These factors included age (p &lt; 0.001), nodule orientation (p = 0.0232), calcification (p = 0.0034), and operator experience (p = 0.0286). After the multivariate analysis, five independent factors were identified to improve the diagnostic results of FNA for solid thyroid nodules: (1) the presence of Hashimoto&rsquo;s thyroiditis (odds ratio (OR) = 1.810; 95% confidence interval (CI): 1.076&ndash;3.045; p = 0.0254), (2) a taller-than-wide orientation (OR = 2.038; 95% CI: 1.260&ndash;3.296; p = 0.0037), (3) the presence of calcification (OR = 1.767; 95% CI: 1.115&ndash;2.799; p = 0.0153), (4) four needle passes to obtain material (OR = 1.750; 95% CI: 1.094&ndash;2.799; p = 0.0196), and (5) an experienced operator (OR = 0.561; 95% CI: 0.319&ndash;0.987; p = 0.0451). Conclusions: A taller-than-wide orientation, the presence of calcification, and the presence of Hashimoto&rsquo;s thyroiditis were found to affect the sample adequacy of ultrasound-guided FNA with liquid-based cytology. The sample adequacy could be improved when FNA is performed with four needle passes by experienced doctors