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IntroductionAllium macrostemon Bge. (AMB) and Allium chinense G. Don (ACGD) are both edible Allium vegetables and named officinal Xiebai (or Allii Macrostemonis Bulbus) in East Asia. Their medicinal qualities involve in lipid lowering and anti-atherosclerosis effects. And steroidal saponins, nitrogenous compounds and sulfur compounds are like the beneficial components responsible for medicinal functions. Sulfur compounds are the recognized main components both in the volatile oils of AMB and ACGD. Besides, few researches were reported about their holistic chemical profiles of volatile organic compounds (VOCs) and pharmacodynamic effects.MethodsIn this study, we first investigated the lipid-lowering and anti-atherosclerotic effects of volatile oils derived from AMB and ACGD in ApoE–/– mice with high fat and high cholesterol diets.ResultsThe results showed the volatile oils of AMB and ACGD both could markedly reduce serum levels of TG, TC, and LDL-C (p < 0.05), and had no alterations of HDL-C, ALT, and AST levels (p > 0.05). Pathological results displayed they both could obviously improve the morphology of cardiomyocytes and the degree of myocardial fibrosis in model mice. Meanwhile, oil red O staining results also proved they could apparently decrease the lesion areas of plaques in the aortic intima (p < 0.05). Furthermore, head space solid phase microextraction coupled with gas chromatography tandem mass spectrometry combined with metabolomics analysis was performed to characterize the VOCs profiles of AMB and ACGD, and screen their differential VOCs. A total of 121 and 115 VOCs were identified or tentatively characterized in the volatile oils of AMB and ACGD, respectively. Relative-quantification results also confirmed sulfur compounds, aldehydes, and heterocyclic compounds accounted for about 85.6% in AMB bulbs, while approximately 86.6% in ACGD bulbs were attributed to sulfur compounds, ketones, and heterocyclic compounds. Multivariate statistical analysis showed 62 differentially expressed VOCs were observed between AMB and ACGD, of which 17 sulfur compounds were found to be closely associated with the garlic flavor and efficacy.DiscussionTaken together, this study was the first analysis of holistic chemical profiles and anti-atherosclerosis effects of AMB and ACGD volatile oils, and would benefit the understanding of effective components in AMB and ACGD.

Real-time forecasting of travel demand during wildfire evacuations is crucial for emergency managers and transportation planners to make timely and better-informed decisions. However, few studies focus on accurate travel demand forecasting in large-scale emergency evacuations. Therefore, this study develops and tests a new methodological framework for modeling trip generation in wildfire evacuations by using (a) large-scale GPS data generated by mobile devices and (b) state-of-the-art AI technologies. The proposed methodology aims at forecasting evacuation trips and other types of trips. Based on the travel demand inferred from the GPS data, we develop a new deep learning model, i.e., Situational-Aware Multi-Graph Convolutional Recurrent Network (SA-MGCRN), along with a model updating scheme to achieve real-time forecasting of travel demand during wildfire evacuations. The proposed methodological framework is tested in this study for a real-world case study: the 2019 Kincade Fire in Sonoma County, CA. The results show that SA-MGCRN significantly outperforms all the selected state-of-the-art benchmarks in terms of prediction performance. Our finding suggests that the most important model components of SA-MGCRN are evacuation order/warning information, proximity to fire, and population change, which are consistent with behavioral theories and empirical findings.

Accurate shared micromobility demand predictions are essential for transportation planning and management. Although deep learning models provide powerful tools to deal with demand prediction problems, studies on forecasting highly-accurate spatiotemporal shared micromobility demand are still lacking. This paper proposes a deep learning model named Interactive Convolutional Network (ICN) to forecast spatiotemporal travel demand for shared micromobility. The proposed model develops a novel channel dilation method by utilizing multi-dimensional spatial information (i.e., demographics, functionality, and transportation supply) based on travel behavior knowledge for building the deep learning model. We use the convolution operation to process the dilated tensor to simultaneously capture temporal and spatial dependencies. Based on a binary-tree-structured architecture and interactive convolution, the ICN model extracts features at different temporal resolutions, and then generates predictions using a fully-connected layer. The proposed model is evaluated for two real-world case studies in Chicago, IL, and Austin, TX. The results show that the ICN model significantly outperforms all the selected benchmark models. The model predictions can help the micromobility operators develop optimal vehicle rebalancing schemes and guide cities to better manage the shared micromobility system.

In this paper, we study block Jacobi operators on $\mathbb{Z}$ with quasi-periodic meromorphic potential. We prove the non-perturbative Anderson localization for such operators in the large coupling regime.

Recommended technologies for the tourism system, such as the travelocity.com and visiteurope.com, have gained tremendous popularity in the past few years. Although many research works have been dedicated to improving recommendation services and overcoming recommendation challenges, little attention has been attached to the application of recommended technology in Rural Tourism. In order to solve the difficult ‘what to choose’ problem caused by information overload, this paper combines the features of Rural Tourism, giving a first attempt in this field. First, an effective method of seasonal feature extraction is proposed. Next, a detailed method of geographical distribution feature extraction is described. In particular, a block-number basing on the geographical distribution feature to the Attractions is proposed. Furthermore, the FM-based (Factorization Machines) algorithm is presented as a recommended solution for Rural Tourism. Finally, the comparative experiments are provided to prove the effectiveness of this solution.

In power Internet of Things environment, the existing border-based protection system and the “one-time authentication, one-time authorization, and long-term effective” approach are difficult to deal with the threat of attacks from internal and external devices and users with legal authority. In order to solve the problem of authorized access of power equipment and users, combined with behavior risk assessment, a continuous trust evaluation scheme of power equipment and users is presented in this paper. The scheme is evaluated by the combination of direct trust, indirect trust, and comprehensive trust and adds the penalty reward factor and time attenuation function to improve the reliability of the results. In addition, this paper will quantify the risk of the behavior of power equipment and users and regard it as a factor affecting the degree of trust, so as to achieve continuous trust evaluation of equipment and users.

Sugar alcohols are the prominent alternatives of sugars in food, medical, and health industries. The ruthenium supported on multiwalled carbon nanotubes (Ru/MWCNTs) catalysts were prepared based on the Ru valence regulation strategy and applied for selective sugar hydrogenation to prepare various sugar alcohols including xylitol, arabinitol, sorbitol, mannitol, and galactitol for the first time, with high selectivity (>99.0%) and yield (>98.0%) under mild conditions (≤110 °C, 3.0 MPa H2 pressure). The hydrogenation reaction of xylose was further optimized and under mild conditions (100 °C, 3.0 MPa H2 pressure, and 500 rpm), which were lower than ever reported for high efficient synthesis of xylitol, 99.8% xylose conversion and 99.0% xylitol yield were achieved after 120 min of reaction.

Immunotherapy, closely associated with immune infiltration and tumor mutation burden (TMB), is emerging as a promising strategy for treating tumors, but its low response rate in hepatocellular carcinoma (HCC) remains a major challenge. Herein, we applied two algorithms to uncover the immune infiltration landscape of the immune microenvironment in 491 HCC patients. Three immune infiltration patterns were defined using the CIBERSORT method, and the immune cell infiltration (ICI) scores were established using principal component analysis. In the high ICI score group, the activation of the Wnt/β-catenin pathway was significantly enriched and expressions of immune checkpoint genes increased, which showed a pessimistic outcome. The low ICI score group was characterized by increased TMB and enrichment of metabolism-related pathways. Further analysis found that the ICI score exhibited a significant difference in age ≥65/age

Background: Pegylated recombinant human granulocyte colony-stimulating factors (PEG-rhG-CSFs) are more commonly and widely used than recombinant human granulocyte colony-stimulating factors (rhG-CSFs) in preventing chemotherapy-induced neutropenia in patients with stage II-IV breast cancer. To reduce the financial burden on these patients, the corresponding medical insurance directory needs to be revised.Objectives: To evaluate the cost-effectiveness of PEG-rhG-CSF versus rhG-CSF in patients with stage II-IV breast cancer in central China.Methods: Two Markov models, a chemotherapy model and a post-chemotherapy model, were developed to study the effects and costs, with a time horizon of 12 weeks and 35 years, respectively. Cost and probability input data were primarily obtained from a retrospective real-world study conducted in five tertiary hospitals. Propensity score matching was adopted to overcome retrospective bias. Other parameters were extracted from literature as well as advice from clinical experts. Univariate and probabilistic sensitivity analyses were conducted.Results: In the first chemotherapy model, PEG-rhG-CSF was associated with fewer episodes of febrile neutropenia (FN) (N = 19 per 1000 patients treated), infections (N = 24 per 1000 patients treated) and deaths (N = 2 per 1000 patients treated), but higher costs (¥36 more per patient treated). The post-chemotherapy model indicated that PEG-rhG-CSF led to higher gains in quality-adjusted life years (QALYs) (11.695 versus 11.516) in comparison to rhG-CSF. Sensitivity analysis showed that the cost of PEG-rhG-CSF had the greatest impact on the incremental costs, and incremental QALYs were very sensitive to the risk of RDI Conclusion: According to this economic evaluation based on real-world data, PEG-rhG-CSF may be considered as a more cost-effective strategy relative to rhG-CSF for stage II-IV breast cancer patients in central China. However, to reflect a national perspective, further evidence is needed using data from larger-scale studies.

Additional file 1.

Additional file 1: Figure S1. Scatterplot of polymyxin B AUCss,24h versus dosage. AUCss,24h, the area under the plasma concentration-time curve across 24 hours at steady state. Figure S2. Scatterplot of polymyxin B AUCss,24h (a) and C0h (b) stratified for different stages of acute kidney injury. AUCss,24h, the area under the plasma concentration-time curve across 24 hours at steady state; C0h, trough concentration. Figure S3. Kaplan-Meier estimates of survival to 30 days after administration of polymyxin B. Stratified by AUCss,24h (a) and C0h (b). AUCss,24h, the area under the plasma concentration-time curve across 24 hours at steady state; C0h, trough concentration.

Additional file 1. The checklist of the research.

Additional file 2: Box 1. Questions used in the interview guide.

A lipase from Sporisorium reilianum SRZ2 (SRL) with 73% amino acid sequence identity to Candida antarctica lipase B (CALB) was cloned and overexpressed in Pichia pastoris. The recombinant SRL showed a preference for short-chain p-nitrophenyl esters. It achieved maximum activity at pH 8.0 and 65°C for p-nitrophenyl hexanoate (C6) with Km and kcat/Km values of 0.14 mmol·L−1 and 1712 min−1 · mmol · L−1 at 30°C, respectively. SRL displayed excellent thermostability and pH stability, retaining more than 79% of its initial activity after incubation at 60°C for 72 h and 75% at pH 3 to 11 for 72 h. It also maintained most of its activity in the presence of inhibitors and detergents except sodium dodecyl sulfate, and it tolerated organic solvents. SRL was covalently immobilized and successfully used for ethyl hexanoate synthesis in cyclohexane or in a solvent-free system with a high conversion yield (> 95%). Furthermore, high conversion yield was also achieved for the synthesis of various short-chain flavor esters when high substrate concentrations of 2 mol · L−1 were applied. This study indicated that a CALB-type lipase from S. reilianum SRZ2 showed great potential in organic ester synthesis.

Tacrolimus is a major immunosuppressor against post-transplant rejection in kidney transplant recipients. However, the narrow therapeutic index of tacrolimus and considerable variability among individuals are challenges for therapeutic outcomes. The aim of this study was to compare different machine learning and deep learning algorithms and establish individualized dose prediction models by using the best performing algorithm. Therefore, among the 10 commonly used algorithms we compared, the TabNet algorithm outperformed other algorithms with the highest R2 (0.824), the lowest prediction error [mean absolute error (MAE) 0.468, mean square error (MSE) 0.558, and root mean square error (RMSE) 0.745], and good performance of overestimated (5.29%) or underestimated dose percentage (8.52%). In the final prediction model, the last tacrolimus daily dose, the last tacrolimus therapeutic drug monitoring value, time after transplantation, hematocrit, serum creatinine, aspartate aminotransferase, weight, CYP3A5, body mass index, and uric acid were the most influential variables on tacrolimus daily dose. Our study provides a reference for the application of deep learning technique in tacrolimus dose estimation, and the TabNet model with desirable predictive performance is expected to be expanded and applied in future clinical practice.

The Candida Antarctica lipase B (CALB) was embedded in the metal-organic framework, zeolitic imidazolate framework-8 (ZIF-8) and applied in the enzymatic synthesis of L-ascorbic acid palmitate (ASP) for the first time. The obtained CALB@ZIF-8 achieved the enzyme loading of 80 mg/g with 11.3 U/g (dry weight) unit activity, 59.8% activity recovery and 92.7% immobilization yield. Under the optimal condition, ASP was synthesized with over 75.9% conversion of L-ascorbic acid in a 10-batch reaction. Continuous synthesis of ASP was subsequently performed in a packed bed bioreactor with an outstanding average space-time yield of 58.1 g L-1 h-1 , which was higher than ever reported continuous ASP biosynthesis reactions. This article is protected by copyright. All rights reserved.

Candida antarctica lipase B (CALB) is a robust biocatalyst for production of chemicals. In this study, an engineered lipase B (CALB-I189K) was covalently immobilized onto a glutaraldehyde activated amino resin (ESR-3) and used for the preparation of chiral moxifloxacin precursor though enzymatic resolution of cis-(±)-dimethyl 1-acetylpiperidine-2,3-dicarboxylate (cis-(±)-1). The immobilization conditions were optimized, and the immobilized CALB-I189K exhibited improved thermal stability, with a half-life of 247.5 h at 30 °C. It enables the resolution of 100 g L–1 cis-(±)-1 for 50 cycles in a stirred tank reactor, with an average productivity of 49.6 g L–1 h–1. The resolution reaction was also performed in a recirculating packed bed reactor (RPBR) in a semicontinuous mode, and the average productivity reached 59.4 g L–1 h–1 under the optimal operating condition. Moreover, the RPBR bioconversion system has high operational stability and conserved over 85.7% of the initial conversion capacity after 50 cycles...

Asymmetric synthesis of chiral epichlorohydrin (ECH) from 1,3-dichloro-2-propanol (1,3-DCP) using halohydrin dehalogenases (HHDHs) is of great value due to the 100% theoretical yield and high enantioselectivity. The vital problem in the asymmetric synthesis is to prepare optically pure ECH. In this study, key amino acid residues located at halide ion channels of HheC (P175S/W249P) (HheCPS) were modified to regulate the kinetic parameters. HheCPS I81W, F86N and V94R were constructed with the corresponding halide ion channels destroyed. The catalytically efficiencies (kcat/Km) of the three mutants exhibited 0.38-, 0.23- and 0.23-fold decrease toward (S)-ECH and the reverse reaction was significantly inhibited. As the results, (S)-ECH was synthesized with >99% enantiomeric excess (e.e.) and 63.42%, 67.08% and 57.01% yields, respectively, under 20 mM 1,3-DCP as substrate. To our knowledge, this is the first investigation of the molecule kinetic modification of HHDHs and also the first report for the biosynthesis of optically pure (S)-ECH from 1,3-DCP using HHDHs.

The construction of the power Internet of Things has led various terminals to access the corporate network on a large scale. The internal and external business interaction and data exchange are more extensive. The current security protection system is based on border isolation protection. This is difficult to meet the needs of the power Internet of Things connection and open shared services. This paper studies the application scheme of the “zero trust” typical business scenario of the power Internet of Things with “Continuous Identity Authentication and Dynamic Access Control” as the core, and designs the power internet security protection architecture based on zero trust.

With the development of cloud computing, artificial intelligence, big data and other technologies, network systems are facing more and more security risks and threats. The traditional security architecture based on border protection cannot meet the increasing security protection requirements. The zero-trust security architecture which has the characteristics of continuous identity authentication and minimized authority allocation can adapt to the security protection requirements of most current network systems. Based on the zero-trust security architecture, a dynamic access control and authorization system is proposed. User portraits and user trust are generated according to user behavior. Real-time hierarchical control in different scenarios is used in the system to achieve dynamic and fine-grained access control and authorization.

Ezetimibe is a top-selling hypolipidemic drug for the treatment of cardiovascular diseases. Biosynthesis of (4S)-3-[(5S)-5-(4-fluorophenyl)-5-hydroxypentanoyl]-4-phenyl-1,3-oxazolidin-2-one ((S)-ET-5) using carbonyl reductase has shown advantages including high catalytic efficiency, excellent stereoselectivity, mild reaction conditions, and environmental friendness, and was considered as the key step for ezetimibe production. The regeneration efficiency of the cofactor, nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) is one of the main restricted factor. Recombinant Escherichia coli strain (smCR125) coexpressing carbonyl reductase (CR125) and glucose dehydrogenase were successfully constructed and applied for the production of (S)-ET-5 for the first time. Without extra addition of the coenzyme NADPH, the yield of 99.8% and the enantiomeric excess (e.e.) of 99.9% were achieved under ET-4 concentration of 200 g/L. Using a substrate fed-batch strategy, under the optimal conditions, the substrate ET-4 concentration was increased to 250 g/L with the yield of 98.9% and the e.e. of 99.9% after 12 hr reaction. The space-time yield of 494.5 g L-1 d-1 and the space-time yield per gram biocatalyst of 24.7 g L-1 d-1 g-1 DCW were achieved, which were higher than ever reported for the biosynthesis of the ezetimibe intermediate.

Asymmetric synthesis of chiral epichlorohydrin (ECH) from 1,3-dichloro-2-propanol (1,3-DCP) using halohydrin dehalogenase (HHDH) is of great value due to the 100% theoretical yield and high enantioselectivity. In this study, HheC (P175S/W249P) was immobilized on an A502Ps resin and used for the preparation of (S)-ECH. In aqueous system, the immobilized HheC catalyzed the biosynthesis of (S)-ECH with 83.78% yield and 92.53% enantiomeric excess (ee) at 1,3-DCP concentration of 20 mM. The non-aqueous system was further developed using water saturated ethyl acetate as solvent and reaction phase. The non-aqueous bioconversion system showed higher enantioselectivity (>98% ee) toward (S)-ECH production with modest conversion (52.34%) compared with ever reported aqueous reactions. Batch reactions were performed in a packed-bed bioreactor for 45 batches in aqueous phase and 24 batches in non-aqueous phase. The present work demonstrated the potential of immobilized HheC (P175S/W249P) in aqueous and non-aqueous phase biosynthesis of chiral ECH.

In this study, a carbonyl reductase RtSCR9 from Rhodosporidium toruloides was engineered to improve its activity for asymmetric reduction of N,N-dimethyl-3-keto-3-(2-Thienyl)-1-keto propanamine (DMAK) to (S)-3-(dimethylamino)-1-(2-Thienyl)-1-propanol (S-DMAA). Error-prone polymerase chain reaction (epPCR) combined with megaprimer PCR of whole plasmid (MEGAWHOP) method and site saturation mutagenesis was used to construct random mutant libraries. The positive mutant was screened by measuring the decrease in the absorbance of NADPH at 340 nm and high performance liquid chromatography (HPLC). The best Mut-A89N/F154Y was obtained and compared with wild type RtSCR9, the Vmax and kcat of Mut-A89N/F154Y were enhanced by 2.08 and 3.86-fold, respectively, while the Km decreased by 2.36-fold. The reduction of DMAK by Mut-A89N/F154Y afforded S-DMAA with a yield of 91.2% and enantiomeric excess of 99.9% at 2 M DMAK, which was highest ever reported. This mutant could be a potential candidate for the upscale production of S-DMAA.

To develop a method for fast replacement of promoters to improve protein production. A method (entitled retreat to advance or “ReToAd”), which includes a deleting PCR and a touchdown PCR, was validated by replacing seven IPTG-inducible promoters with enhanced green fluorescent protein (eGFP). The seven promoters were fully recovered by sequencing only 30 clones. The activity of E. coli harboring ω-transaminase (ω-TA) was increased from 112 U/mg cells (T7 promoter) to 147 U/mg cells (Trc promoter) by combining ReToAd and screening experiments. After screening a library comprising glutamate dehydrogenase (GDH) expressed by different promoters, the activity of E. coli cell harboring Trc-promoter-expressed GDH was ~31-fold higher than that of T7-promoter-expressed GDH. The “ReToAd” for in situ rapid replacement of promoters was developed and optimized, and one round of “ReToAd” can be completed within 3 days.

Candida antarctica lipase B (CALB) is a versatile and robust lipase with high activity and enantioselectivity in the resolution of alcohols and amines. Poor specific activity toward carboxylic esters that are branched or substituted in close proximity to the carboxyl group limits the application of CALB. In this study, a semi-rational engineering approach was successfully applied to tailor CALB for efficient synthesis of the moxifloxacin chiral intermediate through enzymatic resolution of cis-(±)-dimethyl 1-acetylpiperidine-2,3-dicarboxylate. The combinatorial active-site saturation test was performed on CALB and two key residue sites, 189 and 190, were identified in the determination of hydrolytic activity. The specific activity and catalytic efficiency (kcat/Km) of the best variant mut-I189K were increased by 286- and 193-fold, respectively, without impacting its enantioselectivity. With 0.1 g L−1 of purified mut-I189K loading, 1 M substrate was asymmetrically hydrolyzed with 49.9% conversion within 5 h, resulting in a space–time yield of 583.8 g L−1 d−1. These results demonstrated that mut-I189K is a competitive biocatalyst for large-scale preparation of the moxifloxacin chiral intermediate.

(4 S )-3-[(5 S )-5-(4-Fluorophenyl)-5-hydroxypentanoyl]-4-phenyl-1,3-oxazolidin-2-one (( S )-ET-5) is an important chiral intermediate in the synthesis of chiral side chain of ezetimibe. Recombinant Escherichia coli expressing carbonyl reductase (CBR) was successfully constructed in this study. The total E. coli biomass and the specific activity of recombinant CBR in 5 L fermenter culture were 10.9 g DCW L −1 and 14900.3 U g −1 DCW, respectively. The dual-enzyme coupled biocatalytic process in an aqueous-organic biphasic solvent system was first constructed using p -xylene as the optimal organic phase under optimized reaction conditions, and 150 g L −1 (4 S )-3-[5-(4-fluorophenyl)-1,5-dioxophentyl]-4-phenyl-1,3-oxazolidin-2-one (ET-4) was successfully converted to ( S )-ET-5 with a conversion of 99.1% and diastereomeric excess of 99% after 24-h, which are the highest values reported to date for the production of ( S )-ET-5.

Alcohol dehydrogenases (ADHs), which belong to the oxidoreductase superfamily, catalyze the interconversion between alcohols and aldehydes or ketones with high stereoselectivity under mild conditions. ADHs are widely employed as biocatalysts for the dynamic kinetic resolution of racemic substrates and for the preparation of enantiomerically pure chemicals. This review provides an overview of biotechnological applications for ADHs in the production of chiral pharmaceuticals and fine chemicals.

A rapid, sensitive, selective and accurate ultra high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the quantitation of prucalopride in rat plasma using carbamazepine as an internal standard (IS). Separation was achieved on a Waters ACQUITY UHPLC(®) HSS C18 column (2.1mm×50mm, 1.8μm) column with a gradient mobile phase consisting of acetonitrile-water (containing 0.1% formic acid) as mobile phase at a flow rate of 0.2mL/min. Prucalopride and IS were monitored using positive electrospray triple quadrupole mass spectrometer (Waters Xevo TQD) via multiple reaction monitoring (MRM) mode. The monitored transitions were set at m/z 367.99→195.89 and m/z 236.97→194.04 for prucalopride and IS, respectively. The achieved lower limit of quantitation was 0.1ng/mL. The validated method had an excellent linearity in the range of 0.1-100ng/mL (r>0.996). The intra- and inter-day precisions were both≤7.8% for prucalopride and IS, and the average intra- and inter-day accuracies ranged from -3.0% to 8.5%. Extraction recoveries at three levels QC concentrations were in the range of 90.0-110.0% for prucalopride and 99.6% for IS. Matrix effects were found to be acceptable. The validated assay was successfully applied to a pharmacokinetic study of prucalopride following oral administration of 0.25, 0.5, 1.0mg/kg to female and male rats respectively.

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is an important chiral intermediate for the synthesis of rosuvastatin. The biotechnological production of (3R,5S)-CDHH is catalyzed from tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) by a carbonyl reductase, and this synthetic pathway is becoming a primary route for (3R,5S)-CDHH production due to its high enantioselectivity, mild reaction conditions, low cost, process safety, and environmental friendship. However, the requirement of the pyridine nucleotide cofactors, reduced nicotinamide adenine dinucleotide (NADH) or reduced nicotinamide adenine dinucleotide phosphate (NADPH) limits its economic flexibility. In the present study, a recombinant Escherichia coli strain harboring carbonyl reductase R9M and glucose dehydrogenase (GDH) was constructed with high carbonyl reduction activity and cofactor regeneration efficiency. The recombinant E. coli cells were applied for the efficient production of (3R,5S)-CDHH with a substrate conversion of 98.8%, a yield of 95.6% and an enantiomeric excess (e.e.) of >99.0% under 350 g/L of (S)-CHOH after 12 hr reaction. A substrate fed-batch strategy was further employed to increase the substrate concentration to 400 g/L resulting in an enhanced product yield to 98.5% after 12 hr reaction in a 1 L bioreactor. Meanwhile, the space-time yield was 1,182.3 g L-1 day-1 , which was the highest value ever reported by a coupled system of carbonyl reductase and glucose dehydrogenase.

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate [(3R,5S)-CDHH] is the key chiral intermediate to synthesize the side chain of the lipid-lowering drug rosuvastatin. Carbonyl reductases showed excellent activity for the biosynthesis of (3R,5S)-CDHH. The requirement of cofactor NADH/NADPH leads to high cost for the industrial application of carbonyl reductases. In this study, a self-sufficient biocatalyst based on carbonyl reductase and NADP+ co-immobilization strategy was developed on an amino resin carrier LX-1000HAA (SCR-NADP+@LX-1000HAA). The self-sufficient biocatalyst achieved in situ cofactor regeneration and showed the activity recovery of 77.93% and the specific activity of 70.45 U/g. Asymmetric synthesis of (3R,5S)-CDHH using SCR-NADP+@LX-1000HAA showed high enantioselectivity (> 99% e.e.) and yield (98.54%). Batch reactions were performed for ten cycles without extra addition of NADP+, and the total yield of (3R,5S)-CDHH achieved at 10.56 g/g biocatalyst. The present work demonstrated the potential of the self-sufficient biocatalyst for the asymmetric biosynthesis of rosuvastatin intermediate.

The key to deal with cyber security threats of gird is making full use of cyber and electrical information, and improving the ability of self-adaptation and automation for malicious attack event identification. In this Paper, the malicious attack correlation analysis method integrating the interaction process of Source-Grid-Load System (SGLS) is proposed. Firstly, the electrical events and information events in the source network are uniformly preprocessed. Secondly, based on the neural network model, the fused events are trained and classified according to the attack scenarios. Thirdly, combined with electrical abnormal events, the genetic algorithm’s initialization scheme, the selection operator and cross genetic probability are improved. The association rules for different attack scenarios are automatically generated based on the classification results. Finally, the proposed method is verified to be effective in the Source-Grid-Load simulation experiment system. The method utilizes the abnormal events of the cyber layer and the electrical layer comprehensively, and improves the identification accuracy of cyber attacks, realizes automatic event classification and correlation rule generation, showing great potential in engineering application.

The creation of an R-selective ω-amine transaminase (ω-ATA) as biocatalyst is crucial for the asymmetric amination of prochiral ketones to produce sitagliptin intermediates because rare ω-ATAs are R-selective in nature and most of them suffer from poor stability and low activity toward bulky prochiral ketones. Here, the gene of an R-selective ω-ATA was cloned from Arthrobacter cumminsii ZJUT212 (AcATA) and expressed in Escherichia coli. The best variants (M1 + M122H and M1+T134 G) were obtained using a semi-rational protein design after screening. These variants not only exhibited improved activity and substrate affinity but also enhanced stability in aqueous phase containing 20 % dimethyl sulfoxide. The conversion of asymmetric amination on 50 g/L pro-sitagliptin ketone PTfpB (1-[1-piperidinyl]-4-[2,4,5-trifluorophenyl]-1,3-butanedione) achieved 92 %, with an extremely high e.e. of >99 %, using 2 gDCW/L E. coli cells harboring M1 + M122H as biocatalyst. In the kilogram-scale experiment, approximately 40 kg of (R)-APTfpB (e.e. >99 %) was produced within 30 h when 50 kg PTfpB was used as the substrate. Furthermore, the space–time yield reached ≈32 g/(L·d).

A novel and rapid microwave extraction and ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of 25 bioactive constituents (including two new constituents) in Fructus Alpinia oxyphylla. The optimized conditions of the microwave extraction was a microwave power of 300 W, extraction temperature of 80°C, solvent-to-solid ratio of 30 mL/g and extraction time of 8 min. Separation was achieved on a Waters ACQUITY UPLC(®) HSS C18 column (2.1 mm× 50 mm, 1.8 μm) using gradient elution with a mobile phase consisting of acetonitrile and 1 mM ammonium acetate at a flow rate of 0.2 mL/min. This is the first report of the simultaneous determination of 25 bioactive constituents in Fructus Alpinia oxyphylla by ultra high performance liquid chromatography with tandem mass spectrometry. The method was validated with good linearity, acceptable precision and accuracy. The validated method was successfully applied to determine the contents of 25 bioactive constituents in Fructus Alpinia oxyphylla from different sources and the analysis results were classified by hierarchical cluster analysis, which indicated the effect of different cultivation regions on the contents of constituents. This study provides powerful and practical guidance in the quality control of Alpinia oxyphylla and lays the foundation for further research of Alpinia oxyphylla.

Two guanidine bases were used as organocatalysts for the synthesis of cyclic monothiocarbonates via the coupling reaction of carbonyl sulfide (COS) and epoxides. The systems proved to be efficient single-component, metal-free catalysts for the reaction of simple (propylene oxide, 1,3-butene oxide) or activated epoxides (epichlorohydrin, glycidyl phenyl ether) with COS under solvent-free and mild reaction conditions to selectively afford the corresponding cyclic monothiocarbonates. The yield of this reaction is generally high, thereby providing ready means for pure product isolation.

At present, the Source-Grid-Load Friendly Coordination System is relatively weak in dealing with professional organized complex attack. To deal with the security problem, this paper designs anomaly monitoring framework of Source-Grid-Load Friendly Coordination System which includes the network communication anomaly monitoring and the Source-Grid-Load interactive terminal anomaly monitoring. For the network communication anomaly monitoring, a method based on rule-matching is used to identify anomaly events of the sensitive business operation, detecting business command exceptions by analyzing the business command features of the system. For the Source-Grid-Load interactive terminal anomaly monitoring, a method based on the security policy is used to monitor the anomaly status of the terminal by matching malicious behavior in real time.

tert -Butyl (3 R ,5 S )-6-chloro-3,5-dihydroxyhexanoate ((3 R ,5 S )-CDHH) is the key intermediate for synthesis of atorvastatin and rosuvastatin. Carbonyl reductase exhibits excellent activity toward tert -butyl ( S )-6-chloro-5-hydroxy-3-oxohexanoate (( S )-CHOH) to synthesize (3 R ,5 S )-CDHH. In this study, a whole cell biosynthesis reaction system to produce (3 R ,5 S )-CDHH was constructed in organic solvents. A solution of 10% ( v/v ) Tween-80 was introduced to the reaction system as a co-solvent, which greatly enhanced biotransformation process, giving 98.9% yield, >99% ee and 1.8-fold higher space time yield in 5 h bioconversion of 1 M ( S )-CHOH, compared with 98.7% yield and >99% ee in 9 h bioconversion of a purely aqueous reaction system. Moreover, a water-octanol biphasic reaction system was built and 20% of octanol was added as reservoir of substrate resulting in 98% yield, >99% ee and 4.08 mmol L −1 h −1 g −1 (wet cell weight) space time yield. This study paved a way for the whole cell biosynthesis of (3 R ,5 S )-CDHH in mono and biphasic media.

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is a key intermediate of atorvastatin and rosuvastatin synthesis. Carbonyl reductase RtSCR9 from Rhodosporidium toruloides exhibited excellent activity toward tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH). For the activity of RtSCR9 to be improved, random mutagenesis and site-saturation mutagenesis were performed. Three positive mutants were obtained (mut-Gln95Asp, mut-Ile144Lys, and mut-Phe156Gln). These mutants exhibited 1.94-, 3.03-, and 1.61-fold and 1.93-, 3.15-, and 1.97-fold improvement in the specific activity and kcat/Km, respectively. Asymmetric reduction of (S)-CHOH by mut-Ile144Lys coupled with glucose dehydrogenase was conducted. The yield and enantiomeric excess of (3R,5S)-CDHH reached 98 and 99%, respectively, after 8 h bioconversion in a single batch reaction with 1 M (S)-CHOH, and the space-time yield reached 542.83 mmol L–1 h–1 g–1 wet cell weight. This study presents a new carbonyl reductase for efficient sy...

The bio-inspired geomagnetic navigation is inspired from animals navigation behavior which dispense with the priori geomagnetic data. It can be employed by AUV for a navigation task that arrived to targeting point which is characterized with geomagnetic multi-parameter through magnetotaxis searching behavior. However, the geomagnetic anomalies area could form an extreme value region and disturb the magnetotaxis behavior to make AUV lost in the navigation space. This paper proposes an improved navigation model using a course constraint strategy to force AUV escaping from extreme value region. Firstly, we generalize disturbance to navigation process as a problem of population prematurity in evolution algorithm. The behavior constraints strategy is designed in order to avoid the prematurity of the population, forcing the AUV perform a specific action, expanding the scope of the exploration, thus bypass the abnormal area. Then, the statistics characteristics of magnetotaxis and convergence state of multi-objective functions are utilized to construct the trigger and termination conditions of behavioral constraints, and better historical data of magnetotaxis is taken as the constraint course. The evolution population is updated with the movement of vehicle and finally leads the vehicle to get to the destination potion. Finally, compared the present model with probability evolution strategy. The simulation results show that this method can effectively overcome the abnormal disturbance to the bio-inspired geomagnetic navigation and enhance the success rate of autonomous long-distance navigation.

The evaluation of the effect of ecological restoration project is studied in this paper. Taking Qilihai wetland as a case, a comprehensive evaluation model based on System Dynamics (SD) is proposed. Firstly, the evaluation index system is established according to the actual situation of the wetland ecological restoration project, and the weight of each index can be calculated by Analytic Hierarchy Process (AHP). Then the simulation model based on SD is constructed, so the value of each evaluation index before and after the implementation of the project can be obtained. Finally, the comprehensive evaluation index before and after the project can be obtained with the weighted average method. The results show the model is effective and applicable.

In vitro transfection of cultured cells combined with nuclear transfer currently is the most effective procedure to produce transgenic livestock. In the present study, bovine primary fetal fibroblasts were transfected with a green fluorescent protein (GFP) reporter transgene and used as nuclear donor cells in oocyte reconstructions. To examine the role of host cytoplasm on transgene expression and developmental outcome, GFP-expressing fibroblasts were fused to oocytes reconstructed either metaphase or telophase activation, and PCR technology was also employed. The results showed that GFP became detectable at the 8- to 16-cell stage, approximately 80 h after reconstruction, and remained positive at all later stages. Embryonic development to the blastocyst stage was not significantly different among metaphase and telophase groups. Therefore, GFP transgene technology can be used to select embryoes derived from transgenic animals.

The gas diffusion layer (GDL), as an important structure of the membrane electrode assembly (MEA) of the direct methanol fuel cell (DMFC), provides a support layer for the catalyst and the fuel and the product channel. Traditionally, the material of GDL is generally carbon paper (CP). In this paper, a new material, namely three-dimensional graphene (3DG) is used as GDL for micro DMFC. The experimental results reveal that the performance of the DMFC has been improved significantly by application of 3DG. The peak powers increase from 25 mW to 31.2 mW and 32 mW by using 3DG as the anode and cathode GDL instead of CP, respectively. The reason may be the decrease of charge and mass transfer resistance of the cell. This means that the unique 3D porous architecture of the 3DG can provide lower contact resistance and sufficient fuel diffusion paths. The output performance of the cell will be further improved when porous metal current collectors is used.

A global approximation based adaptive radial basis function (RBF) neural network control strategy is proposed for the trajectory tracking control of supercavitating vehicles (SV). A nominal model is built firstly with the unknown disturbance. Next, the control scheme is established consisting of a computed torque controller (CTC) for the practical vehicle and an RBF neural network controller to estimate model error between the practical vehicle and the nominal model. The network weights are adapted by employing a Lyapunov-based design. Then it is shown by the Lyapunov theory that the trajectory tracking errors asymptotically converge to a small neighborhood of zero. The control performance of the proposed controller is illustrated by simulation.

Summary Background. RNA interference (RNAi) is a potential therapeutic tool in the treatment of various diseases, such as cancers and viral infections. Silencing of E7 genes is an effective method to suppress human papilloma virus (HPV)-related tumours. Aim. To determine the therapeutic potential of RNAi in controlling condyloma acuminatum (CA). Methods. Small interfering (si)RNA duplexes or small-hairpin (sh)RNA-expressing plasmids targeting the E7 genes of HPV-6b or HPV-11were inoculated into cultured E7-expressing cells via cationic liposomes, or into E7 gene-expressing mouse tumour models intratumorally or intravenously. Experiments were performed in triplicate and E7 mRNA level was analysed by real-time PCR. Results. The in vitro experiments found that both siRNAs and shRNA-expressing plasmids reduced the mRNA levels of HPV-6b or HPV-11 E7 to 20–40% at the optimum dosage of 25–50 nmol/L for siRNAs and 0.1–0.2 μg/mL for shRNA-expressing vectors. The optimum time for this to happen was 72 h. E7 mRNA expression in tumour models was reduced to 45–50% after three intratumural injections. Intratumoral injections of RNAi effectors induced greater inhibition than did intravenous injections. Conclusions. We conclude that HPV-6b/11 E7 gene expression can be specifically modulated by RNAi, which may provide a useful method in the management of CA.

Factoring plays a crucial role in solving the financing problems, which are common among small and medium enterprises (SMEs). In this paper, we develop decision models by considering non-recourse factoring and recourse factoring respectively in a supply chain which includes a bank and a seller. Then we find the optimal discount rate of factoring in two scenarios. Finally, we study the influence of the seller's equity fund and the probability of bad debts on the discount rate of factoring by numerical example and sensitivity analysis.

Two parallel hybrid processes (Biological filter Coagulation/Ultrafiltration(BCUF) and Coagulation/Ultrafiltration(CUF)) for treating slightly polluted surface water were carried out in this experiment. In the process of BCUF, transverse flow water-dropping aerated biological filter was used as a primary pretreatment, and coagulation was used as the subsequent pretreatment of Ultrafiltration(UF). In the CUF process, coagulation was the unique pretreatment of UF. Turbidity was removed nearly completely in both two hybrid processes, and in the BCUF, effective ammonia nitrogen removal (87.1%) was also achieved mainly through the biological nitrification carried out in the biological filter, however, only 25.6% removal of ammonia nitrogen was achieved in the process of CUF. The removal rates of CODMn, TOC, DOC, UV254, AOC and BDOC were 55.2%, 87.8%, 71.0%, 61.1%, 91.4% and 89.3% respectively in the process of BCUF, which were much higher than that in the process of CUF. The biological pretreatment could improve the biological stability significantly and relieve the membrane fouling which made the transmembrane pressure (TMP) arising velocity lower. The pretreatment of biological filter and coagulation could remove the organic molecules in the range of 5000-500Da. Results showed the water-dropping aerated biological filter was fit for the pretreatment of UF.