Quimica Nova最新文献_第6页

AROMATICITY OF AZA AROMATIC MOLECULES: PREDICTION FROM HÜCKEL THEORY WITH MODIFIED PARAMETERS 含杂芳香族分子的芳香性:基于hÜckel修正参数理论的预测

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230017

I. Sutjahja, Yuanita Sudarso, S. Ulhaq, Erik Yutomo

{"title":"AROMATICITY OF AZA AROMATIC MOLECULES: PREDICTION FROM HÜCKEL THEORY WITH MODIFIED PARAMETERS","authors":"I. Sutjahja, Yuanita Sudarso, S. Ulhaq, Erik Yutomo","doi":"10.21577/0100-4042.20230017","DOIUrl":"https://doi.org/10.21577/0100-4042.20230017","url":null,"abstract":"Hückel theory is a simple and powerful method for predicting the molecular orbital and the energy of conjugated molecules. However, the presence of nitrogen atoms in aza aromatic molecules alters the Coulomb and resonance integrals owing to the difference in electronegativity between nitrogen and carbon atoms. In this study, we focus on acridine and phenazine. Further correction is implemented based on the ring current model, thus revealing the change in resonance integral for the carbon–carbon bond along the bridge of the molecule. The Hamiltonian of the π–electron system in the Hückel method is solved using the HuLiS software. Various geometry-based aromaticity indices are used to obtain the aromaticity indices of the two non-equivalent rings. For further evaluation, the results for bond lengths are used to calculate the associated bond energy. Considering the carbon–hydrogen (CH) bonds, the total molecular energy is compared with the experimental heats of formation for a number of benzenoid hydrocarbons and aza aromatics, in addition to the two studied molecules. Finally, the correlation between the nitrogen atom on the aromaticity index and the ring energy content is evaluated to determine to which extent the Hückel model agrees with previous experimental and advanced computational studies.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

STABLE ISOTOPES OF OXYGEN AND HYDROGEN IN WATER: ANALYTICAL METHOD EVALUATION AND THE DETERMINATION OF δ18O AND δ2 H ON A CONTROL SAMPLE 水中氧和氢的稳定同位素:分析方法、评价和对照样品δ18o和δ 2h的测定

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230021

André Martins, Edinei Koester, Leandro Rosalino, Ronaldo Bernardo, F. Leitzke

{"title":"STABLE ISOTOPES OF OXYGEN AND HYDROGEN IN WATER: ANALYTICAL METHOD EVALUATION AND THE DETERMINATION OF δ18O AND δ2 H ON A CONTROL SAMPLE","authors":"André Martins, Edinei Koester, Leandro Rosalino, Ronaldo Bernardo, F. Leitzke","doi":"10.21577/0100-4042.20230021","DOIUrl":"https://doi.org/10.21577/0100-4042.20230021","url":null,"abstract":"Evaluation studies contribute to the identification of parameters that can affect the accuracy and precision of analytical methods. This study describes the analysis of δ18O and δ2H in water samples by the equilibrium method at the Isotope Geology Laboratory (LGI), Center for studies in Petrology and Geochemistry (CPGq) of the Federal University of Rio Grande do Sul (UFRGS). For that, six batches of analyzes were carried out under different ambient temperature conditions. For the reproducibility tests, four aliquots of the control sample were analyzed at the Polar Climate Center (CPC). Results showed that ambient temperature did not significantly affect the accuracy of the oxygen analysis. However, the mean result at 20 °C showed greater accuracy and acceptable precision. Hydrogen analyzes at a room temperature of 18 °C showed an external standard deviation and an internal precision exceeding the recommended, while at 20 and 22 °C the results were statistically acceptable, being the first more accurate. From that, it is possible to conclude that the determination of δ18O and δ2H in water at the LGI, employing the equilibrium method at an ambient temperature of 20 °C, showed satisfactory repeatability and reproducibility.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

QUESTÕES REGULATÓRIAS SOBRE A DESINFECÇÃO DA ÁGUA E O IMPACTO DA GERAÇÃO DE DBPs NA QUALIDADE DA ÁGUA TRATADA 关于水消毒的监管问题和DBPs的产生对处理过的水质量的影响

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230029

B. Vizioli, Cassiana Montagner

{"title":"QUESTÕES REGULATÓRIAS SOBRE A DESINFECÇÃO DA ÁGUA E O IMPACTO DA GERAÇÃO DE DBPs NA QUALIDADE DA ÁGUA TRATADA","authors":"B. Vizioli, Cassiana Montagner","doi":"10.21577/0100-4042.20230029","DOIUrl":"https://doi.org/10.21577/0100-4042.20230029","url":null,"abstract":"REGULATORY ISSUES ON WATER DISINFECTION AND THE IMPACT OF DBP GENERATION ON DRINKING WATER QUALITY. Drinking water disinfection has been viewed as one of the major advances in public health protection in history. However, while it has been very successful in assuring microbiological safety, disinfection also brought relevant concerns about chemical safety and the potential unintended health hazards associated with disinfection byproduct (DBP) exposure. DBPs represent one of the most important groups of chemical compounds to which humans are exposed through drinking water, as epidemiological studies have consistently associated long-term exposure with multiple adverse health effects. It is established that disinfection is an essential component of providing microbiologically safe drinking water and shall never be compromised. Yet, chemical safety regarding DBP exposure remains a largely uncovered and highly discussed topic. Several DBPs have been reported in the past few decades, yet research on formation, toxicity and occurrence remains scarce for most compounds. Also, for each identified DBP, many remain undiscovered. In view of an ever-growing list of DBPs and the existing gaps in available research, identifying overall driving agents of toxicity is still a major challenge for public health protection. This review attempts to provide an insight on contemporary issues regarding the overall safety of drinking water and the trade-off between microbiological and chemical risks, considering current challenges in water and sanitation access and existing regulations.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

VALIDATION OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF FATTY ACIDS IN SHEEP BLOOD SERUM SAMPLES 绵羊血清样品中脂肪酸测定方法的验证

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230009

Matheus Bazzana, Juliana Garcia, Gabriela Vilela, C. Borges, L. Faria, Nadja Alves, A. Saczk

{"title":"VALIDATION OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF FATTY ACIDS IN SHEEP BLOOD SERUM SAMPLES","authors":"Matheus Bazzana, Juliana Garcia, Gabriela Vilela, C. Borges, L. Faria, Nadja Alves, A. Saczk","doi":"10.21577/0100-4042.20230009","DOIUrl":"https://doi.org/10.21577/0100-4042.20230009","url":null,"abstract":"Low-density dispersive liquid-liquid microextraction with a subsequent esterification step was proposed in this study for the determination of linoleic acid and stearic acid in sheep blood serum samples. The method developed aimed to quickly and efficiently extract and esterify both fatty acids with subsequent analysis by gas chromatography/flame ionization detection. The extraction method was optimized with Scheffé’s polynomial model for three-component mixtures. The method was validated according to the parameters established by Eurachem Guide (2014). The optimal extraction conditions for LD-DLLME were 1400 µL of dispersion medium (MgCl2 0.017%), 400 µL of extractor solvent (toluene) and 1200 µL of dispersion solvent (methanol). The method performance showed adequate selectivity, sensitivity and precision to be applied to real samples, with an average recovery of 98.54% for linoleic acid and 103.83% for stearic acid. LD-DLLME was superior to the traditional method of analysis, which has been used until now for the determination of fatty acids in blood serum samples from ruminants. The analysis of real samples showed that the developed method is efficient for monitoring these substances in ruminants.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

PLANEJAMENTO DE FÁRMACOS CONTRA COVID-19: UMA EXPERIÊNCIA DE ENSINO REMOTO DE QUÍMICA FARMACÊUTICA COVID-19药物规划:药物化学远程教学经验

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230020

Rhanna da Silva, L. Monteiro, C. Branco, Fernanda Guilhon-Simplicio

{"title":"PLANEJAMENTO DE FÁRMACOS CONTRA COVID-19: UMA EXPERIÊNCIA DE ENSINO REMOTO DE QUÍMICA FARMACÊUTICA","authors":"Rhanna da Silva, L. Monteiro, C. Branco, Fernanda Guilhon-Simplicio","doi":"10.21577/0100-4042.20230020","DOIUrl":"https://doi.org/10.21577/0100-4042.20230020","url":null,"abstract":"DRUG DESIGN AGAINST COVID-19: A REMOTE TEACHING EXPERIENCE IN PHARMACEUTICAL CHEMISTRY. Infront of with the difficulties faced in making a new drug available to the population, it is essential to seek ways to simplify the process. In silico methodologies are alternatives to benchtop experiments, being frequently used due to their speed and low cost. The present study aimed to formulate a theoretical-practical activity in the Pharmaceutical Chemistry course, where students applied their knowledge of structural modeling and molecular docking to propose bioactive compounds against molecular targets of the SARS-CoV-2 virus. The class was divided, and each group presented a drug candidate, the precursors being natural molecules. In total, seven derivatives were designed and tested against different macromolecules, and then an in silico prediction of their physicochemical characteristics was performed. The docking results were positive for all derivatives, in terms of binding energy, mainly GEND with –9.0 kcal mol-1. In addition, the prototypes exhibited good interactions with the amino acids of the respective targets, mainly KAED, QUED and GEND, in addition to presenting adequate physicochemical properties for meeting the Lipinski restrictions. Therefore, this study presented at least three potential inhibitors of SARS-CoV-2, showing the importance of using computational tools in drug design and development, as well as in teaching practice.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

INTELLIGENT DELIVERY OF ANTITUMOR DRUGS MEDIATED BY POLYMERIC NANOMICELLES: A REVIEW 高分子纳米胶束介导抗肿瘤药物的智能递送研究进展

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230011

R. Martins, A. Duarte, F. Cotinguiba

引用次数: 0

QUANTITATIVE AND QUALITATIVE CHARACTERIZATION OF THE GRANULOMETRY OF AN INCEPTISOL 首赛地醇颗粒剂的定量和定性研究

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230018

Janaina Schadosin, S. Saab, A. Brinatti, L. Pires

{"title":"QUANTITATIVE AND QUALITATIVE CHARACTERIZATION OF THE GRANULOMETRY OF AN INCEPTISOL","authors":"Janaina Schadosin, S. Saab, A. Brinatti, L. Pires","doi":"10.21577/0100-4042.20230018","DOIUrl":"https://doi.org/10.21577/0100-4042.20230018","url":null,"abstract":"Granulometry is an initial factor to be considered in soil research as it plays a fundamental role in physical and chemical properties. The objective of this study was to characterize the granulometric fractions of soil, obtained using the screening and sedimentation method. The Dynamic Light Scattering (DLS), Mid-Infrared (MIR), and Scanning Electron Microscopy with Field Emission Gun (SEM-FEG) techniques were used for this purpose. The quantitative results showed that this soil presents high percentage of clay, followed by fine sand fraction, silt fraction and, finally, the coarse sand fraction. The results obtained by DLS qualify this technique as a procedure to evaluate the quality of the granulometric fractionation of the clay fraction. The MIR analyzes detected characteristic vibrational states of minerals such as kaolinite, halloysite, gibbsite, and quartz. Few works in the literature characterize the clay fraction of the soil without chemical treatment using the SEM-FEG technique. Thus, in this work, pseudo-hexagonal structures were identified, typical of the kaolinite mineral and, to a lesser extent, structures with a filamentous needle-like morphology, which can be ascribed to illite and/or halloysite, whose inorganic functional groups were identified by MIR in the clay fraction of the soil.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"51 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68271036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

SÍNTESE, CARACTERIZAÇÃO DE UMA BASE DE SCHIFF DE QUITOSANA E COMPLEXOS DE COBRE UTILIZADAS COMO ELETRODO MODIFICADO 基地的合成、表征希夫QUITOSANA复杂铜作为电极的修改

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230019

Ana Pontes, Talita Pontes, N. Cavalcante, Francimar de Sousa Júnior, Francisco da Silva, Daniel Pontes

引用次数: 0

INVESTIGAÇÃO DA ATIVIDADE ELETROQUÍMICA DE LIGA Al-Cu-Li APÓS PROCESSO DE SOLDAGEM POR FRICÇÃO E MISTURA Al-Cu-Li合金摩擦混合焊接后的电化学活性研究

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-29 DOI: 10.21577/0100-4042.20230014

Rejane Ferreira Da Silva., M. Milagre, J. V. Araujo, Oscar Ramirez, C. Machado, R. Antunes, Isolda Costa

{"title":"INVESTIGAÇÃO DA ATIVIDADE ELETROQUÍMICA DE LIGA Al-Cu-Li APÓS PROCESSO DE SOLDAGEM POR FRICÇÃO E MISTURA","authors":"Rejane Ferreira Da Silva., M. Milagre, J. V. Araujo, Oscar Ramirez, C. Machado, R. Antunes, Isolda Costa","doi":"10.21577/0100-4042.20230014","DOIUrl":"https://doi.org/10.21577/0100-4042.20230014","url":null,"abstract":"INVESTIGATION OF THE ELECTROCHEMICAL ACTIVITY OF AN Al-Cu-Li ALLOY AFTER FRICTION STIR WELDING PROCESS. In this work, the local electrochemical activity of the zones coupled by Friction Stir Welding (FSW) of an Al-Cu-Li alloy was studied and the results were correlated to the microstructural characteristics of each zone. Electrochemical studies were carried out in the zones affected by welding using cyclic voltammetry (CV) and scanning electrochemical techniques (namely, SECM - Scanning Electrochemical Microscopy and LEIS – Local electrochemical impedance spectroscopy). The results showed that the welding joint (WJ) is predominantly cathodic relatively to the heat affected zones (HAZ). The HAZ was always anodic and showed the highest electrochemical activities among the tested ones. The high electrochemical activity of the HAZ was associated with the effect of galvanic coupling between the cathodic region (WJ) and the anodic region (HAZ). In addition, the advancing side (AS) presented increased electrochemical activity compared to the retreating one (RS).","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"05 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

EFFECT OF ELECTRIC PULSE TREATMENT ON MICROSTRUCTURE, ELECTROCHEMICAL AND DISCHARGE PROPERTIES OF AZ61 ANODES FOR Mg-AIR BATTERIES 电脉冲处理对镁空气电池AZ61阳极微观结构、电化学和放电性能的影响

IF 0.8 4区化学

Quimica Nova Pub Date : 2023-05-08 DOI: 10.21577/0100-4042.20230010

Jin-dian Zou, Tao Zhang, Zhiquan Huang, Chunjiang Zhao, Junpeng Wang

{"title":"EFFECT OF ELECTRIC PULSE TREATMENT ON MICROSTRUCTURE, ELECTROCHEMICAL AND DISCHARGE PROPERTIES OF AZ61 ANODES FOR Mg-AIR BATTERIES","authors":"Jin-dian Zou, Tao Zhang, Zhiquan Huang, Chunjiang Zhao, Junpeng Wang","doi":"10.21577/0100-4042.20230010","DOIUrl":"https://doi.org/10.21577/0100-4042.20230010","url":null,"abstract":"In this work, the effects of electric pulse treatment on the discharge and electrochemical properties of rolled and extruded AZ61 as anode of Mg-air battery were studied. The microstructure, electrochemical behavior and surface morphology after discharge were discussed to relate the discharge performance. The experimental results show that compared with the original magnesium anode (rolled and extruded), the magnesium anode treated by electric pulse has more negative corrosion potential, lower impedance value, higher discharge voltage and better specific energy. This is because electric pulse treatment can cause the coarse second phase in magnesium anode to dissolve and the grains to become more uniform. In particular, in the discharge process, the surface of magnesium anode after electric pulse treatment will form micro cracks, which is beneficial to promote the self-stripping of discharge products. It is worth noting that the effect of electric pulse treatment on rolled anode is better than that of extruded anode. It may be due to the different dislocation density in the two anodes. During the electric pulse treatment, the dislocation density in the alloy is highly correlated with the dissolution rate of β-Mg17Al12, which ultimately affects the volume fraction of the second phase in the alloy.","PeriodicalId":49641,"journal":{"name":"Quimica Nova","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68270327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0