Evaluation of the Antimicrobial Effect of Thymoquinone against Different Dental Pathogens: An In Vitro Study

This study aimed to evaluate the antimicrobial effect of Thymoquinone (TQ) on four different oral microorganisms. Minimum Bactericidal Concentration (MBC), Minimum Inhibition Concentration (MIC), Broth microdilution, and Well diffusion tests were used to determine the optimum antimicrobial concentrations of TQ against Streptococcus salivarius, Streptococcus oralis, Streptococcus mutans, and Staphylococcus aureus over 1, 3, 6, 12 and 24 h. Chlorhexidine 0.12% was selected as a positive control. The inhibitory effect of TQ on bacterial growth was most noticeable with S. salivarius, while the least affected was S. aureus. TQ’s MBC and MIC for S. oralis and S. aureus were comparable 2 mg/mL and 3 mg/mL, respectively. S. salivarius was most resistant to TQ and displayed a value of 5 mg/mL and 4 mg/mL for MIC and MBC, respectively. The viable count of different strains after exposure to TQ’s MBC values was most noticeable with S. aureus followed by S. oralis and S. mutans, while S. salivarius was least affected. This study emphasized the promising antimicrobial effect of TQ against the four main oral microorganisms. It has a potential preventive effect against dental caries as well as other oral diseases.     

毛细管气相色谱法测定芝麻中多种有机磷农药残留量

建立了芝麻中多种有机磷农药残留量的毛细管气相色谱的测定方法。样品以V(乙腈 )∶V(丙酮 ) =1 0∶1混合溶剂为提取剂 ,应用超声波辅助提取 ,固相吸附层析柱净化m(中性氧化铝 )∶m(弗罗里硅土 ) =1∶1 ,采用GC FPD法同时测定芝麻中的多种有机磷农药残留量。检出限为 0 .0 1 1～ 0 .0 1 7μg mL。方法的回收率为 82 .1 %～ 1 0 9.7%。     

含氟体系中DDR型分子筛的合成

DDR (Deca-dodecasil 3R) zeolite was synthesized hydrothermally in fluoride medium. The effects of synthesis conditions including the amount of KF, different fluoride sources and seeds on crystallization of DDR zeolite were investigated. The as-synthesized DDR zeolite samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results demonstrated that DDR crystallization was strongly affected by n_KF/n_SiO2, fluoride sources and seeds. Pure DDR zeolite could be successfully obtained in n_KF/n_SiO2 range of 0.5～1 after 9 days of hydrothermal synthesis. The synthesis time was reduced to 1 day by adding small amount of seeds with yield approaching 100%.     

Simultaneous determination of polyphenolic compounds in red and white grapes grown in Sardinia by high performance liquid chromatography–electron spray ionisation-mass spectrometry

A new method for the identification and the quantification of nonanthocyanin phenolic compounds from six Vitis Vinifera grape varieties native to Sardinia (three native: Vermentino, Malvasia and Cannonau and three non-native types: Chardonnay, Sauvignon and Cabernet Sauvignon; Argiolas vineyard) was developed. This rapid and selective method employs LC/ESI-MS in negative mode. Different solvents extraction and different sorbents for purification were compared to the direct analysis of the initial extracts without further sample preparation. A total of 54 phenolic compounds were identified either in the freeze-dried skins or seeds, including nonflavonoids (hydroxybenzoic and hydroxycinnamic acids and their derivatives, stilbenes) and flavonoids (flavanols, flavonols, dihydroxyflavonols).     

Identification and quantification of glucosinolates in rapeseed using liquid chromatography–ion trap mass spectrometry

A rapid and sensitive method for the speciation and quantification of glucosinolates in rapeseed is described. The method combines liquid chromatography (LC) with ion trap mass spectrometry (ITMS) detection. Electrospray ionization (ESI) has been chosen as the ionization technique for the on-line coupling of LC with ITMS. Glucosinolates are extracted from different rapeseeds with MeOH and the extracts are cleaned-up by solid phase extraction with Florisil cartridges. Aqueous extracts are injected into LC system coupled to an ITMS, leading to accurately quantify eight of the most important glucosinolates in rapeseed, by MS² mode and confirming their structure by MS³ acquisition. All the glucosinolates found in rapeseeds provide good signals corresponding to the deprotonated precursor ion [M-H]⁻. The method is reliable and reproducible, and detection limits range from 0.5 nmol g⁻¹ to 3.7 nmol g⁻¹ when 200 mg of dried seeds of certified reference material are analyzed. Within-day and between-day RSD percentages range between 2.4–14.1% and 3.9–16.9%, respectively. The LC-ESI-ITMS-MS method described here allows for a rapid assessment of these metabolites in rapeseed without a desulfatation step. The overall process has been successfully applied to identify and quantify glucosinolates in rapeseed samples.     

ICP-OES/ICP-MS测定葵花子中28种无机元素

建立了葵花子中微量元素组成的分析方法。采用HNO₃+H₂O₂混合酸为消解体系经微波消解葵花子样品,电感耦合等离子体发射光谱(ICP-OES)法测定葵花子中Al,B,Ca,Fe,K,Mg,Na,Si,P和S,电感耦合等离子体质谱(ICP-MS)法测定葵花子As,Ba,Cd,Co,Cr,Cu,Li,Mn,Mo,Ni,Pb,Rb,Sr,Sn,Sb,Ti,V和Zn。采用国家一级标准物质大米(GBW10045)验证了方法的准确性,结果表明,标准物质的测定结果与参考值基本一致,葵花子中Ca,K,Mg,P,S的含量较高。该方法具有良好的准确性和精密度。     

Contents of heavy metals in lotus seed from REEs mining area

At rare earth mining area, the pollution of heavy metals has been paid little attention. In lotus seeds and soil samples sampled from a typical rare earth elements mining area were detected the contents of eight kinds of heavy metals (Cr, Mn, Cu, Zn, As, Cd, Hg and Pb) to investigate the pollution from rare earth elements mining by ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The results showed that the contents of the heavy metals Cr, Mn, Cu, Zn, As, Cd, Hg and Pb in lotus seeds were 0.25, 86.94, 8.32, 19.76, 0.13, 0.08, 0.01, and 0.20 μg/g in lotus seeds, respectively, and corresponding contents in soil were 27.68, 168.71, 20.23, 47.16, 1.83, 0.13, 0.04, and 23.15 μg/g. These data showed that the contents of heavy metals in lotus seeds from REEs mining area are no higher than reference area and meet national food safety standards of China.     

Lipids ofPhellodendron lavalei seeds

The chemical composition of neutral lipids and phospholipids from seeds ofPhellodendron lavalei cork is studied. Characteristic features of the fine structure of the separate classes are found. Significant quantities of eicosatrienoic acid and neutral lipids are found. The polar lipids are biologically active.Deceased.I. G. Kutateladze Institute of Pharmacochemistry, Academy of Sciences of Georgia, Tbilisi, fax (99532) 25 00 26. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 220–222, May–June, 2000.     

以纯硅silicalite-1为晶种制备空心结构ZSM-5沸石分子筛

微孔分子筛在实际应用过程中常常受到扩散限制的影响,分子筛内部的利用率不高.制备空心结构分子筛对于改善分子筛扩散传质、提高分子筛利用率具有重要意义.以纯硅silicalite-1为晶种,以四丙基氢氧化铵(TPAOH)为结构导向剂制备ZSM-5分子筛,无定型硅铝物种首先在晶种表面晶化生长,同时碱性合成体系的碱度则可以溶解不...     

Raman Method in Identification of Species and Varieties,Assessment of Plant Maturity and Crop Quality—A Review

The present review covers reports discussing potential applications of the specificity of Raman techniques in the advancement of digital farming, in line with an assumption of yield maximisation with minimum environmental impact of agriculture. Raman is an optical spectroscopy method which can be used to perform immediate, label-free detection and quantification of key compounds without destroying the sample. The authors particularly focused on the reports discussing the use of Raman spectroscopy in monitoring the physiological status of plants, assessing crop maturity and quality, plant pathology and ripening, and identifying plant species and their varieties. In recent years, research reports have presented evidence confirming the effectiveness of Raman spectroscopy in identifying biotic and abiotic stresses in plants as well as in phenotyping and digital selection of plants in farming. Raman techniques used in precision agriculture can significantly improve capacities for farming management, crop quality assessment, as well as biological and chemical contaminant detection, thereby contributing to food safety as well as the productivity and profitability of agriculture. This review aims to increase the awareness of the growing potential of Raman spectroscopy in agriculture among plant breeders, geneticists, farmers and engineers.