Optimal Ascent Guidance for Air-Breathing Launch Vehicle Based on Optimal Trajectory Correction

An optimal guidance algorithm for air-breathing launch vehicle is proposed based on optimal trajectory correction. The optimal trajectory correction problem is a nonlinear optimal feedback control problem with state inequality constraints which results in a nonlinear and nondifferentiable two-point boundary value problem (TPBVP). It is difficult to solve TPBVP on-board. To reduce the on-board calculation cost, the proposed guidance algorithm corrects the reference trajectory in every guidance cycle to satisfy the optimality condition of the optimal feedback control problem. By linearizing the optimality condition, the linear TPBVP is obtained for the optimal trajectory correction. The solution of the linear TPBVP is obtained by solving linear equations through the Simpson rule. Considering the solution of the linear TPBVP as the searching direction for the correction values, the updating step size is generated by linear search. Smooth approximation is applied to the inequality constraints for the nondifferentiable Hamiltonian. The sufficient condition for the global convergence of the algorithm is given in this paper. Finally, simulation results show the effectiveness of the proposed algorithm

CW dual-frequency MOPA laser with frequency separation of 45 GHz

A CW dual-frequency master oscillator power amplifier (MOPA) laser system with dozens of gigahertz (GHz) frequency separation is presented. The MOPA system consists of a monolithic microchip seed laser and a double-end pumped traveling wave power amplifier. The short length of seed laser cavity guarantees the seed signal with a large frequency separation (above 53 GHz) but low output power (below 247.8 mW). By adding a long and low-doped active medium laser amplifier stage, a significant increase in laser power and an improvement in beam quality are obtained. After fine temperature tuning of seed laser cavity for spectra matching , a 2.40 W dual-frequency laser signal with 45 GHz frequency separation is achieved

The association between stress hyperglycemia and unfavorable outcomes in patients with anterior circulation stroke after mechanical thrombectomy

Background and purposeStress hyperglycemia is common in critical and severe diseases. However, few studies have examined the association between stress hyperglycemia and the functional outcomes of patients with anterior circulation stroke, after mechanical thrombectomy (MT), in different diabetes status. This study therefore aimed to determine the relationship between stress hyperglycemia and the risk of adverse neurological functional outcomes in anterior circulation stroke patients with and without diabetes after MT.MethodsData of 408 patients with acute anterior circulation stroke treated with MT through the green-channel treatment system for emergency stroke at the First Affiliated Hospital of Jinan University between January 2016 and December 2020 were reviewed retrospectively. The stress hyperglycemia ratio (SHR) was calculated as fasting plasma glucose (mmol/L) divided by glycosylated hemoglobin (%). The patients were stratified into four groups by quartiles of SHR (Q1-Q4). The primary outcome was an excellent (nondisabled) functional outcome at 3 months after admission (modified Rankin Scale score of 0–1). The relationship between stress hyperglycemia and neurological outcome after stroke was assessed using multivariate logistic regression.ResultsAfter adjusting for potential confounders, compared with patients in Q1, those in Q4 were less likely to have an excellent outcome at 3 months (odds ratio [OR], 0.32, 95% confidence interval [CI], 0.14–0.66, p = 0.003), a good outcome at 3 months (OR, 0.41, 95% CI, 0.20–0.84, p = 0.020), and major neurological improvement (OR, 0.38, 95% CI, 0.19–0.73, p = 0.004). Severe stress hyperglycemia increased risks of 3-months all-cause mortality (OR, 2.82, 95% CI, 1.09–8.29, p = 0.041) and ICH (OR, 2.54, 95% CI, 1.21–5.50, p = 0.015).ConclusionStress hyperglycemia was associated with a reduced rate of excellent neurological outcomes, and increased mortality and ICH risks in patients with anterior circulation stroke after MT regardless of diabetes status

Atom Site Selectivity in DNA Alkylation by Primary Diazonium Ions

Diazonium ions are reactive intermediates derived by metabolites of carcinogenic nitrosamines. They can react with DNA at many heteroatoms and form different adducts, which might eventually lead to cancer. Compared to other classical organic alkylating agents, simple diazonium ions react more selectively at oxygen atoms of nucleobases. The resulting oxygen adducts have been shown to be correlated with the mutagenicity of the parent nitrosamines. Therefore, it is of great importance to understand the factors that account for this preference of diazonium ions for oxygen atoms of nucleobases. This work was carried out to study the site selectivity in DNA alkylation by primary diazonium ions using 1- propyldiazonium ion as a tool. The 1- propyldiazonium ion can generate both n- propylation and iso- propylation products. The yield of iso- propylation and the ratio of n- propylation to iso- propylation at a given heteroatom are roughly measurements of the association constant and nucleophilicity of the site to the diazonium ion, respectively. Therefore, the individual effect of the association constants and nulceophilicities on the product yields can be discussed. Alkylation of DNA as well as its nucleoside monomers by 1- propyldiazonium ion was carried out. After hydrolysis, the percent yields of n- propylation and iso-propylation products were determined by HPLC and LC/ MS. The variation in the iso-propylation yields in nucleoside reactions is small and relatively random. In DNA, however, preferential iso- propylation in the minor groove was observed, indicating that the double helix favors the association of 1- propyldiazonium in the minor groove. In the case of the ratio of n- propylation to iso- propylation, the variation is also small in nucleoside reactions. In DNA, however, the ratios of n- propylation to iso- propylation for some sites show significant enhancement, while the others show much smaller enhancement or remain almost the same as compared to the nucleosides. These results demonstrate that the double helix selectively enhances the nucleophilicities of certain sites. Thus, it is the structure of DNA that dictates the atom site selectivity in DNA alkylation by primary diazonium ions

Anthocyanin Biosynthesis Induced by MYB Transcription Factors in Plants

Anthocyanins act as polyphenolic pigment that is ubiquitously found in plants. Anthocyanins play a role not only in health-promoting as an antioxidant, but also in protection against all kinds of abiotic and biotic stresses. Most recent studies have found that MYB transcription factors (MYB TFs) could positively or negatively regulate anthocyanin biosynthesis. Understanding the roles of MYB TFs is essential in elucidating how MYB TFs regulate the accumulation of anthocyanin. In the review, we summarized the signaling pathways medicated by MYB TFs during anthocyanin biosynthesis including jasmonic acid (JA) signaling pathway, cytokinins (CKs) signaling pathway, temperature-induced, light signal, 26S proteasome pathway, NAC TFs, and bHLH TFs. Moreover, structural and regulator genes induced by MYB TFs, target genes bound and activated or suppressed by MYB TFs, and crosstalk between MYB TFs and other proteins, were found to be vitally important in the regulation of anthocyanin biosynthesis. In this study, we focus on the recent knowledge concerning the regulator signaling and mechanism of MYB TFs on anthocyanin biosynthesis, covering the signaling pathway, genes expression, and target genes and protein expression

A Narrow-Linewidth Optical Parametric Oscillator Inserted with Fabry–Perot Etalon

Nowadays, the Fabry–Perot etalon (F–P) has been widely utilized in the optical parametric oscillator (OPO) to improve the filtering performance. In this paper, we reported an F–P etalon composed of two ultra-thin silicon wafers spaced with the air. The linewidth of the signal laser and the threshold are 0.03 nm and 0.6 W, respectively when the proposed etalon is employed to a OPO system based on the MgO-doped LiNbO3 (MgO: PPLN). A stabilized output at 1492.4 nm is obtained, and a tunable, high-precision filtering performance can be achieved by varying the gap distance of the F–P etalon arbitrarily due to its ultra-thin thickness. In addition, the F–P etalon can work on a very wide bandwidth due to its weak absorption during the infrared and terahertz waveband. The high-precision tuning capability and wide-band function of proposed etalon may benefit many applications, including spectroscopy, filtering, and optical communication

Wet cupping for hypertension: a systematic review and meta-analysis

To assess the efficacy and safety of wet cupping in adults with hypertension, we conducted a systematic review and meta-analysis using 13 databases. Wet cupping alone or in combination with antihypertensive medication or acupuncture was used. Seven randomized trials were included, most not of high methodological quality. A few small studies suggested that wet cupping alone versus antihypertensive medication significantly reduced blood pressure and Traditional Chinese Medicine syndrome (hypertension-related symptoms). However based on current evidence, no firm conclusions can be drawn and no clinical recommendations made. Research projects included need validation. Studies indicate that wet cupping is a safe therapy

DataSheet1_Carbon dioxide flux in the drained drawdown areas of Three Gorges Reservoir.doc

A huge amount of CO2 emissions from the drained drawdown areas of reservoirs overturns the previous results in carbon budget. Three Gorges Reservoir (TGR) has a large drawdown area, which accounts for nearly one third of the total area of the TGR. However, the total CO2 emissions from the TGR drawdown area have seldom been estimated by far. To demonstrate the contribution of CO2 emissions from the TGR drawdown areas, the study measured CO2 emissions from the downstream part of the TGR drawdown areas by the chamber method, and synthesized CO2 emissions from the other parts of TGR drawdown areas. Both the diel and seasonal variation indicated that CO2 emission fluxes were significantly higher in the drained season than in the flooded season. The average CO2 emission flux in the drained season was about 1.7 times higher than that in the inundated season in our experiments, and the ratio increased to 4.8 times when other available data was added. CO2 emission flux in the drained season was positively correlated with air temperature, soil temperature at 5 cm depth, soil water content, organic carbon, and soil nitrate nitrogen, but negatively correlated with elevations. CO2 emission from the TGR drawdown area was estimated to be 342.67–495.96 Gg yr−1 in the drained season, and offset about 80% of carbon fixation by vegetation in the TGR drawdown area. Therefore, CO2 emission from the drained soils should be included in the carbon budget of reservoir systems, especially for these reservoirs with a large drawdown area.</p

Characterization of photosystem I from spinach: effect of solution pH.

Our previous work has demonstrated the isolation of photosystem I (PSI) from spinach using ultrafiltration with a final purity of 84%. In order to get a higher purity of PSI and more importantly to develop a practical bioseparation process, key physiochemical properties of PSI and their dependence on operational parameters must be assessed. In this study, the effect of solution pH, one of the most important operating parameters for membrane process, on the property of PSI was examined. Following the isolation of crude PSI from spinach using n-dodecyl-beta-D: -maltoside as detergent, the isoelectric point, aggregation size, zeta potential, low-temperature fluorescence, atomic force microscopy imaging, secondary structure, and thermal stability were determined. Solution pH was found to have a significant effect on the activity, aggregation size and thermal stability of PSI. The results also suggested that the activity of PSI was related to its aggregation size

Determining Discharge Characteristics and Limits of Heavy Metals and Metalloids for Wastewater Treatment Plants (WWTPs) in China Based on Statistical Methods

Industrial wastewater and sewage are both important sources of heavy metals and metalloids in urban wastewater treatment plants (WWTPs). China has made great efforts to control heavy metal and metalloid pollution by setting discharge limits for WWTPs. There is, however, limited discharge data and no systematic methodology for the derivation of discharge limits. In this study, 14 heavy metals and metalloids (Hg, alkyl mercury, As, Cd, Cr, Cr6+, Pb, Ni, Be, Ag, Cu, Zn, Mn, Se) that are listed in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) were selected for the analysis of discharge characteristics while using the supervised monitoring data from more than 800 WWTPs located in nine provinces in China. Of the 14 heavy metals and metalloids, all but alkyl mercury were detected in the discharge water. There was a high rate of detection of As, Cu, Mn, Se, and there were some samples that exceeded the standard concentrations of Cr, Cr6+, Pb, and Ni. Removal rates of Hg, As, Cd, Cr, Cr6+, Pb, Ni, Cu, Zn, Mn, and Se were higher than 40%, comparable to values from other countries. Hg and As were selected to analyze the influencing factors of effluent and derive discharge limits of WWTPs using a statistical method, because these two metals had more detected data than other metals. The study used supervised monitoring data from Zhejiang WWTPs with 99 for Hg and 112 for As. Based on the delta-lognormal distribution, the results showed that geographic location was significantly closely correlated with Hg (P = 0.027 &lt; 0.05) and As (P &asymp; 0 &lt; 0.05) discharge concentrations, while size (for Hg P = 0.695 &gt; 0.05, for As P = 0.088 &gt; 0.05) and influent concentration (R2 &lt; 0.5) were not. Derived Hg and As discharge limits suggest that it is necessary to establish stricter discharge limits for WWTPs, which is more consistent with the real-world situation in China. The study here comprehensively researches the discharge characteristics of heavy metals and metalloids in effluent of WWTPs in China, and developed for the first time in China heavy metals and metalloids discharge limits based on statistical methods. The results may inform special discharge limit settings for WWTPs in China