7,780 research outputs found

    A Review of Global Precipitation Data Sets: Data Sources, Estimation, and Intercomparisons

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    In this paper, we present a comprehensive review of the data sources and estimation methods of 30 currently available global precipitation data sets, including gauge-based, satellite-related, and reanalysis data sets. We analyzed the discrepancies between the data sets from daily to annual timescales and found large differences in both the magnitude and the variability of precipitation estimates. The magnitude of annual precipitation estimates over global land deviated by as much as 300 mm/yr among the products. Reanalysis data sets had a larger degree of variability than the other types of data sets. The degree of variability in precipitation estimates also varied by region. Large differences in annual and seasonal estimates were found in tropical oceans, complex mountain areas, northern Africa, and some high-latitude regions. Overall, the variability associated with extreme precipitation estimates was slightly greater at lower latitudes than at higher latitudes. The reliability of precipitation data sets is mainly limited by the number and spatial coverage of surface stations, the satellite algorithms, and the data assimilation models. The inconsistencies described limit the capability of the products for climate monitoring, attribution, and model validation

    Characteristic Aroma Compounds in Two New Vitis vinifera Cultivars (Table Grapes) and Impact of Vintage and Greenhouse Cultivation

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    ‘Zaoheibao’ (a red tetraploid hybrid) and ‘Wuhecuibao’ (a white triploid hybrid) grapes have beenobtained from Guibao♀ (diploid, Vitis vinifera) × Zaomeigui♂ (diploid, V. vinifera) and Guibao♀ (diploid,V. vinifera) × Wuhebaijixin♂ (triploid, V. vinifera) respectively. Aroma characterisation of the twonew table grape cultivars was firstly done by the investigation of volatile compounds. The influence ofgreenhouse cultivation and vintage on berry aroma was studied as well. The results showed that linalool,decanal, β-damascenone, hexanal and (E)-2-hexenal were the main volatile compounds of the two cultivars,which meant that the floral, fruity and sweet odour were prominent, followed by the herbaceous aroma.Greenhouse cultivation enhanced herbaceous odour in both ‘Wuhecuibao’ and ‘Zaoheibao’ berries,and reduced the floral aroma, contributed mainly by β-damascenone, in ‘Wuhecuibao’, and the sweetaroma, represented mainly by linalool, in ‘Zaoheibao’. The concentrations of the main aroma compoundswere greatly affected by vintage and the intensity of sensorial perception was correspondingly changed,but varietal odour attributes were not significantly altered. These results will not only help promote thecultivation and popularisation of these cultivars, but also will provide valuable data for the use of thesecultivars in future breeding

    Comparison of Proanthocyanidins with Different Polymerisation Degrees among Berry Skins of ‘Shiraz’, ‘Cabernet Sauvignon’, and ‘Marselan’

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    Proanthocyanidins in grape berries are synthesised mainly before véraison, and very little attention ispaid to the evolution of proanthocyanidins (PAs) in grapes from véraison to harvest. The present studyfocused on the changes of flavan-3-ols with different degrees of polymerisation in grape skins and thedifference in proanthocyandin composition of ‘Shiraz’, ‘Cabernet Sauvignon’ and ‘Marselan’ grapes (Vitisvinifera L.). The results show that the content of flavan-3-ols, the percentage of prodelphinidins (%P)and mean degree polymerisation (mDP) found in ‘Cabernet Sauvignon’ berry skins at post-véraison werehigher than those in ‘Shiraz’ and ‘Marselan’ skins. Only monomeric, dimeric, trimeric and polymericflavan-3-ols were detected in the three grape cultivars. Polymers with more than tenfold flavan-3-ol unitsaccounted for a relatively high proportion in grape berry skins, and the content in the three cultivarsdeclined continuously during ripening. Principal component analysis showed that proanthocyanidincontent, composition and mDP at grape harvest stage depended strongly on grape cultivar. This studyprovides some useful information for understanding the accumulation of PAs during berry maturationand this information can be used to improve wine quality

    Tissue-specific Accumulation of Flavonoids in Grape Berries is Related to Transcriptional Expression of VvF3′H and VvF3′5′H

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    The products and the related gene expression of flavonoid metabolism were examined in the skin and pulpof Yan73 (Vitis vinifera L. cv.) grapes, a teinturier variety cultivated in China, and the data were comparedwith those in the skin and pulp of Cabernet Sauvignon (Vitis vinifera L. cv.) grapes, a well-known redvariety. The results showed that, in comparison with the skins of Cabernet Sauvignon, the skins of Yan73berries were characterised by fewer types of flavonols and anthocyanins, a higher level of flavonoids,and a much lower percentage of 3′-hydroxylated flavonols. Flavonoid metabolism was also present in thepulp of Yan73, and the percentages of 3′-hydroxylated flavonols and 3′-hydroxylated flavan-3-ols weresignificantly higher than the percentages of their corresponding 3′,5′-hydroxylated forms. Only flavan-3-ols were found in the pulp of Cabernet Sauvignon. The expression of VvmybA1 exhibited a co-ordinationwith the accumulation of anthocyanins in the pulp of the teinturier cultivar, which showed great similarityto that in the skin. A good correlation was found between the expression of VvF3′H and 3′-hydroxylatedflavonoids, as well as between the expression of VvF3′5′H and 3′,5′-hydroxylated flavonoids in the skin andpulp of the grape berries. It is suggested that tissue-specific accumulation of flavonoids in grape berries isrelated to the transcriptional expression of VvF3′H and VvF3′5′H

    Research on prokaryocyte expression and biological activity of the core region of Bloom’s Syndrome protein

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    To establish an effective approach for inducing expression of the RecQ core of Bloom’s Syndrome protein (BLM642-1290) and assaying its biological activity in vitro, BLM642-1290 recombinant protein was expressed with IPTG at room temperature in Escherichia coli, and then the expressed product was assayed using SDS-PAGE and western blotting. After purification via affinity chromatography, DNA binding activity and unwinding activity of the protein were assessed by fluorescence polarization. Furthermore, the ATPase activity of the protein was also assayed using ultraviolet spectrophotometry based on PiColorLock Gold reagent. An effective expression method was established for BLM protein in E. coli. The obvious bioactivities of the protein were observed in binding to ssDNA or dsDNA, unwinding the dsDNA in the presence of ATP, as well as catalyzing ATP hydrolysis in the presence of ssDNA in vitro. The prokaryocyte expression method of BLM642-1290 was established successfully and the protein with biological activity was obtained from recombinant E.coli. This would be significant to provide a better understanding on BLM protein and facilitate the elucidation of mechanism of pathopoiesia in Bloom’s Syndrome.Keywords: BLM642-1290 protein, induced expression, enzymatic activit

    Floating Microparticulate Oral Diltiazem Hydrochloride Delivery System for Improved Delivery to Heart

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    Purpose: To formulate and evaluate floating microparticulate oral diltiazem delivery system for possible delivery to the heart.Method: Floating microspheres were prepared using cellulose acetate and Eudragit RS100 polymers by emulsion solvent evaporation technique. The dried floating microspheres were evaluated for micromeritic properties (flow properties, density, particle size determination) scanning as well as by electron microscopy, and in vitro floatability and drug release studies.Results: The microspheres showed good buoyancy, good flow properties (angle of repose ranging from 24.29 to 29.02 º), particle size (262.09 to 409.60 μm) and good drug loading (74.29 to 92.09 %). The microspheres were porous, hollow and spherical. All the formulations showed good in vitro controlled drug release in the range of 77.62 ± 2.12 to 97.50 ± 1.04 % at the end of 12 h. Drug release was diffusion-controlled and followed zero order kinetics.Conclusion: Microparticulate floating (gastroretentive) oral drug delivery system of diltiazem prepared using cellulose acetate and Eudragit R5100 may be an effective alternative to conventional oral tablets for cardiac drug delivery.Keywords: Cardiac, Microparticulate, Drug release, Gastroretentive, Floating microspheres, Diltiazem hydrochlorid

    Influence of Dexmedetomidine on Toxicity of Intrathecal Ketamine on Neonatal Rat Spinal Function

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    Purpose: To investigate the influence of dexmedetomidine on the effect of ketamine on developing spinal cord.Methods: Postnatal day 3 (P3) and postnatal day 7 (P7) rat pups received intrathecal ketamine (10 mg/kg b.wt) and/or dexmedetomidine (10 μg/kg b.wt). Spinal reflex function was assessed by evaluating the sensory stimuli based on mechanical withdrawal threshold. Spinal tissue was analysed for activated caspase-3 using monoclonal anti-activated caspase-3. Apoptosis count of the spinal tissue was also measured by Fluoro-Jade C staining while glial reactivity was assessed by ionized calcium binding adapter molecule 1 on Day 7 day following injection. Long-term spinal function in rat pups on postnatal day 35 (P35) was evaluated by measuring the hindlimb withdrawal threshold and gait analysis.Results: Exposure to intrathecal ketamine at 10 mg/kg in P3 and P7 pups decreased mechanical withdrawal thresholds and increase apoptosis and microglial activation in the spinal cord. Altered spinal function, as presented by a decrease in mechanical withdrawal threshold and altered static gait, was observed in P35 rats exposed to intrathecal ketamine on P3. Dexmedetomidine administration did not alter the spinal function and histology of spinal tissue. Co-administration of dexmedetomidine and ketamine suggests that the former reduced apoptosis counts, altered glial responses, increased mechanical withdrawal threshold and improved gait.Conclusion: Dexmedetomidine protects against intrathecal ketamine-induced spinal toxicity in neonatal rats.Keywords: Dexmedetomidine, Intrathecal ketamine, Spinal toxicity, Mechanical withdrawal threshold,Glial reactivity, Gait analysis, Activated caspase-3, Apoptosis coun

    Optimization of Sample Preparation and Phloroglucinol Analysis of Marselan Grape Skin Proanthocyanidins using HPLC-DADESI- MS/MS

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    Proanthocyanidins are a group of oligomeric or polymeric flavan-3-ols that are highly significantcontributors to astringency in grapes and wines. An orthogonal L9(3)4 test was adopted to determine theoptimal extraction conditions and acid-catalysis cleavage of proanthocyanidins in the presence of excessphloroglucinol. The qualitative and quantitative analyses were done using HPLC-DAD-ESI-MS/MS. Theresults showed that the maximum extraction was obtained using 0.3 mol/L of HCl and 0.005 g of ascorbicacid with incubation at 70°C for 20 min. The precision and accuracy of this method were acceptable. Thecomposition of free flavan-3-ols and proanthocyanidins in the skins of ‘Marselan’ grapes (Vitis vinifera L.cv.) was investigated. (-)-Epigallocatechin was found to be the most abundant free flavan-3-ol monomerand terminal subunits, whereas the extension subunits were mainly (-)-epicatechin-3-O-gallate in the earlydevelopmental stages, and primarily (-)-epigallocatechin and (-)-epicatechin in the middle and late stages
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