查看更多>>摘要：The article recalls the big personality of Petru Poni, one of the Romanian pioneers of the research in chemistry. The evocation is realized from the perspective of his contribution in the development of education in the second part of the 19th century as it is reflected mainly in his memoirs "What I wanted to do". The achievement of the objectives of his life did not have a smooth path. However, his willingness to learn, the choice of action instead of resemnation and the purpose to do something meaningful in his life brought him to accomplishment.
查看更多>>摘要：The present study aimed to design macromolecular architectures having imide core in the main chain and bearing two 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide heterocycles in the side chain of each structural units as a synergetic two components key factor to induce attractive flame retardant properties in the resulted materials. The synthesis pathway consisted in the classical polycondensation reaction strategy using a phosphorus-containing diamine synthesized in the laboratory and three commercial dianhydrides co-monomers. The chemical structure confirmation of the phosphorus-containing polyimides has been performed by means of FTIR and NMR spectroscopy. The thermal stability of the products was introspected through TGA analysis. The char yields measured at 900℃ ranged between 35% and 54%. Using these parameters limiting oxygen index values were theoretically calculated. Also, the microscale combustion calorimetry measurements have been conducted, in order to investigate the combustion mechanism of the synthesized phosphorus-containing polyimides.
查看更多>>摘要：Early detection of cancer is essential for saving the life of patients. Needle stochastic sensors were proposed as new tools for the fast screening of biological samples. The design of the stochastic sensors was based on the immobilization of protoporphyrin IX in pastes of S-doped graphene. The selected biomarkers were CEA and CA19-9. High sensitivities, and wide linear concentration ranges as well as low limits of quantification were achieved. The proposed sensors were validated; student t-test shown that the proposed needle stochastic sensors can be reliably used for the pattern recognition and quantification of CEA and CA19-9 in whole blood, gastric tumor tissue, saliva, and urine.
ANA MARIA VARTOLOMEIIOAN CALINESCUDIANA MADALINA DAN
9页
查看更多>>摘要：Chemical methods for the synthesis of esters require the use of high temperatures in the presence of chemical catalysts resulting in undesirable by-products. To avoid these problems the use of biocatalysis can lead to greener products. The aim of this papar is to study the synergism of enzyme catalysis with unconventional techniques suc as microwave or ultrasound assited processes. The effect of different reaction parameters, such as temperature, enzyme loading, ultrasonic amplitude and duty cycle, on the enzymatic synthesis of isoamyl acetate has been evaluated. To highlight the efficiency of unconventional techniques, experiments using conventional methods were also performed. The concetrations of isoamyl acetate obtained by unconventional methods were higher than those achieved under conventional heating, as 478 mgester/gmixture was obtained with ultrasounds in 1 h using 25g/L of enzyme loading, at 50℃ as compared to 387 mgester/gmixture by conventional methods. Mild process conditions and using green techniques (microwaves and ultrasounds) make the biocatalytic procedure a useful way to synthetise esters with application on food, pharmaceutical and cosmetic industries.
查看更多>>摘要：The aquatic chemistry of iron involves many environmental aspects because dissolved iron is present as ferrous and ferric ion and the equilibrium between these two forms depends on many natural or antropogenic factors. This paper aims to provide a brief introduction to chemistry of iron in an oligotrophic lake, a new topic in this domain. A number of 28 sampling were taken from Catamarasti Lake, Botosani (Romania). The main physico-chemical properties showed that the acidity, dissolved oxygen, electrical conductivity and saturation satisfied the water quality criteria for this ecosystem. The results for dissolved iron species indicated that there is no strictly correlation with the variation of oxygen content. Thus, for the samples from NE shore, the contents of ferrous iron are bigger than of ferric iron, for the samples from SW shore the contents are almost equal, because of the low contents of oxygen. For the samples from the middle and from downstream of the lake, the contents of ferric iron are bigger than of ferrous iron, due to the oxygen content recorded.
查看更多>>摘要：Biomedical Named Entity Recognition (BNER) is identification of entities such as drugs, genes, and chemicals from biomedical text, which help in information extraction from the domain literature. It would allow extracting information such as drug profiles, similar or related drugs and associations between drugs and their targets. This venue presents opportunities for improvement even though many machine learning methods have been applied. The efficiency can be improved in case of biological related chemical entities as there are varied structure and properties. This new approach combines two state-of-the-art algorithms and aims to improve the performance by applying it to varied sets of features including linguistic, orthographic, Morphological, domain features and local context features. It uses the sequence tagging capability of CRF to identify the boundary of the entity and classification efficiency of SVM to detect subtypes in BNER. The method is tested on two different datasets 1) GENIA and 2) CHEMDNER corpus with different types of entities. The result shows that proposed hybrid method enhances the BNER compared to the conventional machine learning algorithms. Moreover the detailed study of SVM and the methodologies has been discussed clearly. The linear and non linear text classification can be mapped clearly in the section 3. The final section describes the results and the evaluation of the proposed method.
查看更多>>摘要：Seven 4-amino-5-substituted-1,2,4-triazole-3-thione Schiff base compounds were synthesized reacting 4-amino-5-substituted-1,2,4-triazole-3-thione with dichloro-substituted 5-pyrimidines, and the structures were verified by elemental analysis and spectroscopic techniques (FT-IR, ~1H NMR). Additionally, in vitro antifungal activities of the compounds (named F1～F2; A1～A5) against Grape anthracnose and Wheat gibberellic have been evaluated. The compounds of F1, A4 and A5 were found to be potentially effective antifungal agents against Grape anthracnose, while the others showed the low bioactivity. The antifungal activity of all compounds against Wheat gibberellic were superior to that of fluconazole (standard drug, SD). Particularly, compounds of F1, A1, A4 and A5 exhibited a broad-spectrum antifungal activity against two fungus as compared to the others. Therefore, molecular docking study was carried out to explore the potential interaction between ligands and Fusarium graminearum (PDB ID: 5E9H). The results showed that four compounds had higher affinity compared with fluconazole and form the stable complex with the receptor. Besides, the frontier molecular orbitals (FMOs) and molecular electrostatic potentials (MEP) of four compounds with broad-spectrum antimicrobial activity were also calculated with DFT/ B3LYP /6-31G (d, p) method. The energy gap values (△E_(LUMO-HOMO)) of all the synthesized compounds ranged from 3.307-3.375 eV, which was lower than that of SD (6.248 eV). Additionally, according to MEP the electrophile reaction of 5-substituted groups was beneficial to improving the biological activity against Wheat gibberellic and Grape anthracnose.
查看更多>>摘要：Hormones and Vitamins are extremely important ingredients for healthy growth, development, and regularity of events in metabolism. In our study, it is aimed to compare melatonin hormone and vitamins A, E, D3 of goats, sheep and cows milk. Our sample consisted of 20 Simental Breed Cows, 20 Akkaraman Sheeps, and 20 Native Breeder Goats. Melatonin hormone was analyzed with Enzyme Plate Reader by using Rel Assay branded kit and to determine vitamin's levels high-performance liquid chromatography (HPLC). Goat milk melatonin level was at the highest level at night and summer. Regarding goats' milk, Retinol and tocopherol levels were higher in spring than in summer. Regarding sheep's milk, the melatonin level in the sheep's milk was most elevated at night and spring. There were also statistically significant differences between spring and summer milk of sheep in terms of Retinol, Tocopherol, and Vitamin D3. Retinol and tocopherol levels were higher in spring than in summer, but vitamin D3 was higher in summer than in spring. Regarding cow's milk, the amount of melatonin in milk was highest in winter and least in autumn. The amount of melatonin in spring was found to be higher than the amount of melatonin in summer. The amount of melatonin in spring was near to the amount of melatonin in winter, so there was not a statistical significance between them, and the amount of melatonin in summer was near to the amount of autumn, and no statistical significance was found between them.
查看更多>>摘要：Carbon capturing and storage (CCS) is new technology to remove CO2 from the processes that involve elimination of CO2 as its effect on the environment and incessant increase in temperature of the Earth, makes it interesting as well as most dangerous issue that should be dealt timely to reduce the greenhouse gas emissions. In the present research, the data obtained from the experimental study of CO2 capture pilot plant at the Laboratory of Engineering Thermodynamic in TU Kaiserslautern, Germany, is used for the rate based model validation for different cases using monoethenolamine (MEA) as a solvent. Process simulation sensitivity analysis performed includes a wide range of CO2 concentrations for flue gas of different sources i.e. natural gas fired power plant, exhaust gas recycle and coal based power plant. Results obtained from sensitivity analysis point out the effects of lean loading, stripper pressure, MEA concentration and CO2 concentration in flue gas on energy requirement of reboiler and degree of regeneration using MEA as a solvent for a pilot-scale study. It was found that the specific reboiler duty is least for coal-fired power plant in comparison to the natural gas -fired and exhaust gas recycled power plant, keeping the flow rate of the flue gas constant.
查看更多>>摘要：Layered porous SiO2 (V-SiO2) was designed and prepared from vermiculite by expansion-acidification method, and then used as a catalyst support to prepare Ni/V-SiO2 for dry reforming of methane. It is well known that sintering and carbon deposition of metal particles are two main problems in deactivation of nickel-based catalysts for methane dry reforming. It is reported that strong metal support interaction is a possible solution. Here, a Ni/V-SiO2-H catalyst derived from Ni-phyllosilicate was developed, and compared with the catalyst Ni/V-SiO2-IM by impregnation method. The results showed that the Ni/V-SiO2-H catalyst had high catalytic activity and stability, and the CH4 conversion reached 71.7% at 700 ℃. The reason is that on the one hand, the active metal particles in the catalyst are small (8.3 nm) and relatively evenly dispersed; on the other hand, the catalyst has strong metal support interaction, which improves the anti sintering ability of the catalyst and affects the catalytic activity. It is considered that V-SiO2 as a catalyst support for the preparation of Ni-phyllosilicate may have wide application.
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