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An open-air palladium-catalyzed O-glycosylation was developed using glycals and arylboronic acids with base additives at ambient conditions. The novel approach enabled facile access to various

Tryptophol (TOL) is a metabolic derivative of tryptophan (Trp) and shows pleiotropic effects in humans, plants and microbes. In this study, the effect of Trp and phenylalanine (Phe) on TOL production in Saccharomyces cerevisiae was determined, and a systematic interpretation of TOL accumulation was offered by transcriptomic and metabolomic analyses. Trp significantly promoted TOL production, but the output plateaued (231.02-266.31 mg/L) at Trp concentrations ≥ 0.6 g/L. In contrast, Phe reduced the stimulatory effect of Trp, which was strongly dependent on the Phe concentration. An integrated genomic, transcriptomic, and metabolomic analysis revealed that the effect of Trp and Phe on TOL production was mainly related to the transamination and decarboxylation of the Ehrlich pathway. Additionally, other genes, including thiamine regulon genes (this), the allantoin catabolic genes dal1, dal2, dal4, and the transcriptional activator gene aro80, may play important roles. These findings were partly supported by the fact that the thi4 gene was involved in TOL production, as shown by heterologous expression analysis. To the best of our knowledge, this novel biological function of thi4 in S. cerevisiae is reported here for the first time. Overall, our findings provide insights into the mechanism of TOL production, which will contribute to TOL production using metabolic engineering strategies.

Medium-low speed maglev trains (MSMTs) with a levitation gap of only 8–10[Formula: see text]mm need an adequate decoupling capability on the levitation frames to ensure stability control in levitation, while preventing the train from rolling sideways when in landing. Based on the geometric and kinematic relationships, two types of levitation frames are studied, i.e. levitation frame with end-set air spring (LFEAS) and levitation frame with mid-set air spring (LFMAS). For each levitation frame, the decoupling process and mechanism are analyzed, the analytical equations for the kinematic attitude are derived, the decoupling capability under different excitations is calculated, along with the effect of various structural parameters assessed. In addition, a test method is designed for the rolling of the levitation frame, particularly with the anti-rolling capability of the LFMAS measured. The results indicate that oscillation of the hanger rods and anti-rolling beams can compensate for displacement when the motion of the levitation frame is decoupled, which is the key to the decoupling capability. Also, the position of the anti-rolling devices and the length of hanger rods do not affect significantly the decoupling capability. However, a longer anti-rolling beam is more conducive to decoupling, but it does not affect the anti-rolling capacity of the levitation frame. The maximum roll computed of the LFMAS is 2.84[Formula: see text]mm, which meets the anti-rolling requirement.

BackgroundTryptophol (TOL) is a metabolic derivative of tryptophan (Trp) and shows pleiotropic effects in humans, plants and microbes. The mechanisms of TOL biosynthesis were first explored several decades ago. Nonetheless, a systematic interpretation of TOL over-accumulation is still lacking.ResultsBased on TOL yield, a suitable transformation medium (TM1) was used to culture Saccharomyces cerevisiae strain KMLY1-2. The dynamics of TOL production, cell growth, and gene transcription revealed that TOL production was dependent on cell density and the expression of key genes. Additionally, the effects of Trp and phenylalanine (Phe) on TOL production were tested, and the results showed that Trp can significantly facilitate TOL accumulation, but output plateaued (231.02−266.31 mg/L) at Trp concentrations ≥0.6 g/L. In contrast, Phe reduced the stimulatory effect of Trp, which strongly depended on the Phe concentration. To elucidate the molecular basis and regulatory mechanism of TOL overproduction, an integrated analysis of metabolomics, genomics, and transcriptomics was performed. The results revealed that 1) both the Ehrlich pathway and tryptamine-dependent pathway were involved in S. cerevisiae TOL biosynthesis; 2) Trp increased TOL production by enhancing the Ehrlich pathway, in which the steps of transamination (including aminotransferase genes aro9, aat1, bat2 and his5) and decarboxylation (including decarboxylase genes aro10 and pdc5) played important roles. Of course, this process was assisted by amino acid permease genes agp1 and tat2, dihydrolipoyl dehydrogenase gene lpd1, and transcriptional activator gene aro80, etc.; 3) Phe restricted TOL biosynthesis by repressing the transcript levels of genes such as aat1, his5, aro10, pdc5 and aro80, thus interfering with the transamination and decarboxylation reactions; and 4) under sufficient Trp conditions, the de novo Trp biosynthetic pathway and central carbon metabolism (glycolysis, pentose phosphate pathway, and citrate cycle) of S. cerevisiae were weakened, while the content of some amino acids increased, which may be related to the promotion of yeast cell growth by Trp.ConclusionsIn this study, TOL production of S. cerevisiae was significantly improved, and our integrated multi-omics analyses have provided insights into the understanding of TOL over-accumulation, which will be useful for future production of TOL using metabolic engineering strategies.

Background: For medium and low speed maglev transportation system, the eddy current will be induced in rail, which is made of solid steel, while the train is running. The levitation force of electromagnets will be weakened by the magnetic field generated by eddy current in the rail, especially at the position of the forefront electromagnets. With the increase of train running speed, the eddy current effect will also increase, which will reach 30 % at 100 km/h, and which will directly affect the levitation stability of the train during high-speed running. Put it another way, it will limit the further improvement of the running speed of the medium and low speed maglev train. Aim: In order to solve the above problem, and compensate the levitation force reduced by the eddy current effect. Methods: The FEA method is used to obtain the magnetic field distribution and levitation force changing with the train speed. And taking the middle and low speed maglev trains and rails of Changsha Maglev Express as the research object, we have adopted two solutions, and the prototypes of airsprings and levitation magnets are manufactured and tested in the train. Results: The test result show that the currents of the windings at the front end of the two forefront electromagnets are reduced obviously. Conclusion: In this paper, the medium and low speed maglev train and rail used by Changsha Maglev Express are studied, the eddy current effect is analyzed, and two solutions are proposed. The results show that the solution methods can alleviate the eddy current effects to some extent.

It is always a challenge to achieve the selective recognition between human serum albumin (HSA) and bovine serum albumin (BSA) because of their highly homologous primary structure. In this work, we reported two red-NIR fluorescence probes, BI-FPI and NTPS-FPI, for HSA and BSA differential recognition. BI-FPI showed remarkable emission enhancement toward HSA over BSA, while NTPS-FPI exhibited the opposite selectivity toward BSA. The obvious different interaction for probes with HSA and BSA were demonstrated by site specific competitive binding experiments and molecular docking studies. BI-FPI located within site I of HSA, which mainly depended on the hydrophobic residues and π-π interaction. While NTPS-FPI docked into the interface between subdomains II and IIIA of BSA, and the strong hydrogen bond interaction was the main contributor for the binding. Furthermore, the good calibration graphs of BI-FPI to HSA enabled us to develop the attractive multiple functional probe for qualitatively and quantitatively detecting HSA, and the detection limit (0.01 μM, 0.66 mg/L) met the requirements of traditional HSA assay in serum or in urine (30 mg/L).

Human serum albumin (HSA) is the most abundant protein in human blood plasma. It plays an important role in many physiological functions, and the increase or decrease of HSA can exhibit the conditions of human health. Therefore, the accurate detection of HSA with high selectivity and sensitivity has a great clinical importance. We herein developed four red-emitting benzo[ e ]indolium fluorescent dyes, L1-L4, for probing HSA in a physiological buffer or human urine. Satisfactorily, L2 and L4 showed high selectivity and excellent sensitivity for HSA in both PBS buffer and human urine. L2 was completely embedded in the α-helices from subdomain IIA (Sudlow site I) of HSA, and the limit of detection (LOD) was 13.43 mg L −1 in PBS and 8.91 mg L −1 in urine, respectively. However, L4 inserted into the α-helices from subdomain IIA and IIIA (Sudlow site II) of HSA, and exhibited a lower LOD (1.75 mg L −1 in PBS, 1.50 mg L −1 in urine). Furthermore, the high tolerance of environmental pH and anti-interference of L2 and L4 enabled us to develop the promising molecular probes for HSA.

We reported a new fluorescence probe based on Schiff base with 15-crown-5 ester, DB-15C5, which was easy to synthesize and highly specific for the sensitive determination of human serum albumins (HSA) in physiological media or human urine. DB-15C5 exhibited weak or no fluorescence in the physiological environment because of the typical twisted intramolecular charge transfer (TICT) properties, but the addition of HSA caused the fluorescence switch-on responses of DB-15C5. DB-15C5 inserted into the α-helices from subdomains IIA (Sudlow site I) and IIIA (Sudlow site II) of HSA. The crown ester core embedded in the central cavity of site I, which involved in π-π stacking interactions and H-bond. The triphenylamine group stretched into the cavity of site II and failed to freely rotate, and the TICT excited state of DB-15C5 was restricted. Good calibration graphs of the response to HSA and a notably low limit of detection (LOD) (1.7 nM in PBS, 29.5 nM in urine) enabled us to develop a potent functional molecular probe to determine the HSA content in actual biosystems, which was not affected by other proteins and coexisted ions.

The aim of this study was to elucidate the gastroprotective activity and possible mechanism of involvement of araloside A (ARA) against ethanol- and aspirin-induced gastric ulcer in mice. The experimental mice were randomly divided into control, model, omeprazole (20 mg/kg, orally) and ARA (10, 20 and 40 mg/kg, orally). Gastric ulcer in mice was induced by intragastric administration of 80% ethanol (10 mL/kg) containing 15 mg/mL aspirin 4 h after drug administration on day 7. The results indicated that ARA could significantly raise gastric juice volume and acidity; ameliorate gastric mucosal blood flow, gastric binding mucus volume, ulcer index and ulcer inhibition rate; suppress H

Three new meroterpenoids, ganoleucin A-C ( 1 – 3 ), together with five known meroterpenoids ( 4 – 8 ), were isolated from the fruiting bodies of Ganoderma leucocontextum . The structures of the new compounds were elucidated by extensive spectroscopic analysis, circular dichroism (CD) spectroscopy, and chemical transformation. The inhibitory effects of 1 – 8 on HMG-CoA reductase and α-glucosidase were tested in vitro . Ganomycin I ( 4 ), 5 , and 8 showed stronger inhibitory activity against HMG-CoA reductase than the positive control atorvastatin. Compounds 1 , and 3–8 presented potent noncompetitive inhibitory activity against α-glucosidase from both yeast and rat small intestinal mucosa. Ganomycin I ( 4 ), the most potent inhibitor against both α -glucosidase and HMG-CoA reductase, was synthesized and evaluated for its in vivo bioactivity. Pharmacological results showed that ganomycin I ( 4 ) exerted potent and efficacious hypoglycemic, hypolipidemic, and insulin-sensitizing effects in KK-A y mice.

As a new source of creating competitive advantage, the measurement and evaluation of customer value has guiding significance to the practice of business administration. The system of customer value attributes is proposed based on a review of relevant researches, aims at solving the problem of the lack of quantitative measurement. Delphi method, Analytic Hierarchy Process and Fuzzy evaluation are taken into the calculation of the customer value in this research. Finally, a case of an electronic communication equipment enterprise is presented in order to guide management practice.

Algal bloom model in Xiangxi Bay of Three Gorges Reservoir was established by artificial neural network (ANN) technology. Using stepwise multiple linear regression method, the important environmental factors (dissolved oxygen, pH, total nitrogen, ammonium nitrogen and silicate) were selected as input variables in ANN model. The optimal structure of the ANN model was determined based on leave one out cross validation. The squared correlation coefficient R2, squared correlation coefficient in cross validation Q2 and predictive squared correlation coefficient R2 pred of the optimal ANN model are 0.8267, 0.7460 and 0.7522, respectively. The ANN model has been shown to perform well for simulating the algal bloom in Xiangxi Bay.

Dissolved oxygen characteristics of spring algal bloom in Xiangxi Bay of Three Gorges Reservoir were studied. In surveys, 12 stations have been investigated and 132 samples were collected weekly from February 24 to May 10 in 2008. Chlorophyll a, pH and water temperature could be the significant influence factors to dissolved oxygen in spring algal bloom by using stepwise multiple binomial regression and correlation analysis method. Mean value of dissolved oxygen in Xiangxi Bay during spring algal bloom was 8.555 2.414 mg/L with a minimum and maximum concentration of 4.719 and 19.543 mg/L respectively and dissolved oxygen increased to the peak level as a result of algal bloom occurred in Xiangxi Bay and oxygen released during phytoplankton photosynthesis. Dissolved oxygen decreased from the surface to the bottom in the water column. The spatial change of dissolved oxygen in the bottom was not significant and difference of dissolved oxygen between the surface and the bottom in Xiangxi Bay was more significant than Yangtze River.