-
1
المؤلفون: Tian Ye, Yi-Feng Wang, You-Jie Yu, Feng-Lian Zhang, Tesfaye Tebeka Simur
المصدر: Chinese Chemical Letters. 33:1193-1198
مصطلحات موضوعية: chemistry.chemical_compound, Trifluoromethyl, chemistry, Bond strength, Fluorine, Surface modification, chemistry.chemical_element, General Chemistry, Combinatorial chemistry, Organic molecules
الوصف: Selective functionalization of C–F bonds in trifluoromethyl groups has recently received a growing interest, as it offers atom- and step-economic pathways to access highly valuable mono- and difluoroalkyl-substituted organic molecules using simple and inexpensive trifluoromethyl sources as the starting materials. In this regard, impressive progress has been made on the defluorinative functionalization reactions that proceed via radical intermediates. Nevertheless, it is still a great challenge to precisely control the defluorination process, due to the continuous decrease of the C–F bond strength after the replacement of one or two fluorine atoms with various functionalities. This review article is aimed to provide a brief overview of recently reported methods used to functionalize C–F bonds of CF3 groups via radical intermediates. An emphasis is placed on the discussion of mechanistic aspects and synthetic applications
-
2
المؤلفون: Anteneh Belete, Fikadu Ejeta, Nisha Mary Joseph, Tesfaye Gabriel
المصدر: Current Drug Delivery. 19:129-141
مصطلحات موضوعية: Microcrystalline cellulose, chemistry.chemical_compound, Chromatography, Materials science, Central composite design, chemistry, Mean squared prediction error, Pharmaceutical Science, Wetting, Salbutamol Sulphate, Friability
الوصف: Aim: The present research work was aimed to formulate fast disintegrating tablets (FDTs) of salbutamol sulphate (SBS) using a combination of a superdisintegrant and a subliming agent, optimize the formulation and evaluate the in vitro performance of the developed FDTs. Materials and Methods: A formulation of SBS FDT was developed using a combination of superdisintegrant - crospovidone and subliming agent - Ammonium Bicarbonate (AB) in which formulation variables, namely levels of crospovidone and Microcrystalline Cellulose (MCC):Mannitol (MNTL) ratio, were evaluated for their effects on the response variables, disintegration time, hardness, friability and wetting time, of the resulting FDTs. By employing Central Composite Design (CCD) methodology, the FDTs were optimized to achieve optimum levels of the formulation factors. Results: The desired optimum condition was obtained at 7.82% crospovidone and 70% of 1.56:1 MCC: MNTL ratio, while maintaining AB at 5% level for aesthetic reasons. Under the optimized conditions, the disintegration time, hardness, friability, and wetting time were 14.57 ± 0.53 sec, 7.17 ± 0.82 kg/cm2, 0.311% and 13.14 ± 0.69 sec, respectively. The experimentally observed responses were found to be in close agreement with the predicted values for the optimized formulation. Moreover, the validity of the obtained optimal point was confirmed by the low magnitude of percent prediction error (< 5%). Conclusion: FDTs of SBS were successfully formulated and optimized using CCD employing a combination of a superdisintegrant and a subliming agent.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::7b27a497212a8330047b66dbfe9ecbaf
https://doi.org/10.2174/1567201818666210614094646 -
3
المصدر: Chinese Journal of Chemistry. 40:577-581
مصطلحات موضوعية: chemistry.chemical_compound, Chemistry, General Chemistry, Alkylation, Medicinal chemistry, 4-Dimethylaminopyridine
-
4
المؤلفون: Endale Teju, Negussie Megersa, Meseret Amde, Deribachew Bekana, Asnake Tesfaye
المصدر: Toxicological & Environmental Chemistry. 104:20-35
مصطلحات موضوعية: integumentary system, Health, Toxicology and Mutagenesis, fungi, chemistry.chemical_element, Nanoparticle, Biota, Zinc, Pollution, Acetic acid, chemistry.chemical_compound, Chromium, chemistry, Environmental Chemistry, Solid phase extraction, Water pollution, Nuclear chemistry
الوصف: Water pollution due to toxic metals may pose a significant effect on the environment and the biota indicating the necessity of careful management of their concentration in the system. On the other ...
-
5
المؤلفون: Chao-Jan Liao, Tesfaye Mengiste, Bemnet Mengesha, Sanghun Lee, Yun Zhou, Amir Sharon, Han Han, Namrata Jaiswal
المصدر: New Phytologist. 233:458-478
مصطلحات موضوعية: Physiology, Kinase, Jasmonic acid, Meristem, fungi, food and beverages, Meristem growth, Plant Science, Biology, Cell biology, chemistry.chemical_compound, Solanum lycopersicum, chemistry, Gene Expression Regulation, Plant, RNA interference, Gene expression, Transcriptional regulation, Plant Immunity, Gene, Plant Diseases, Plant Proteins
الوصف: The molecular mechanisms of quantitative resistance (QR) to fungal pathogens and their relationships with growth pathways are poorly understood. We identified tomato TRK1 (TPK1b Related Kinase1) and determined its functions in tomato QR and plant growth. TRK1 is a receptor-like cytoplasmic kinase that complexes with tomato LysM Receptor Kinase (SlLYK1). SlLYK1 and TRK1 are required for chitin-induced fungal resistance, accumulation of reactive oxygen species, and expression of immune response genes. Notably, TRK1 and SlLYK1 regulate SlMYC2, a major transcriptional regulator of jasmonic acid (JA) responses and fungal resistance, at transcriptional and post-transcriptional levels. Further, TRK1 is also required for maintenance of proper meristem growth, as revealed by the ectopic meristematic activity, enhanced branching, and altered floral structures in TRK1 RNAi plants. Consistently, TRK1 interacts with SlCLV1 and SlWUS, and TRK1 RNAi plants show increased expression of SlCLV3 and SlWUS in shoot apices. Interestingly, TRK1 suppresses chitin-induced gene expression in meristems but promotes expression of the same genes in leaves. SlCLV1 and TRK1 perform contrasting functions in defense but similar functions in plant growth. Overall, through molecular and biochemical interactions with critical regulators, TRK1 links upstream defense and growth signals to downstream factor in fungal resistance and growth homeostasis response regulators.
-
6
المؤلفون: Alemu Gizaw, Arun Kumar, Feleke Zewge, Melakuu Tesfaye, Andualem Mekonnen
المصدر: Aqua, Vol 70, Iss 7, Pp 921-947 (2021)
مصطلحات موضوعية: Environmental Engineering, Aqueous solution, co-adsorbent, Health, Toxicology and Mutagenesis, removal, Phosphate, Environmental technology. Sanitary engineering, Environmental sciences, chemistry.chemical_compound, recovery, Adsorption, chemistry, Nitrate, adsorption, nitrate, GE1-350, TD1-1066, Water Science and Technology, Nuclear chemistry, phosphate
الوصف: Nitrogen and phosphorus removal and recovery are considered as one of the interventions to control water bodies' eutrophication by application of various methods. Adsorption is an effective method for phosphate and nitrate removal from wastewater. It is efficient, quick, easy, low-cost and environmentally friendly. Even though different adsorbents have been developed with excellent properties, lack of compilation, lack of consistency in operational conditions, and lack of other important parameters used for direct comparison and practical use selection were observed. The first aim of this review is to provide facts and figures on novel adsorbents used for nitrate, phosphate, and simultaneous nitrate-phosphate removal and recovery. Second, various adsorbents applied for nitrate and phosphate removal have been compared in terms of the number of cycles that the adsorbent used; retained removal capacity (RR); the removal capacity of the adsorbent considering the threshold limit settled by EU and EPA as equilibrium concentration for phosphate (q0.1) and nitrate (q10); and time to reach the equilibrium capacity (t90). Third, based on the aforementioned criteria, the best adsorbents are proposed and this is the key novelty of this review work. Moreover, future aspects and challenges regarding nitrate and phosphate removal and recovery are presented. HIGHLIGHTS Reported novel nitrate, phosphate, and nitrate-phosphate co-adsorbents facts and figures were compiled.; The reported nitrate and phosphate recovery eluents used were assessed.; Adsorbents with nitrate and phosphate qm > 50 mg/g were shortlisted for comparison using q0.1/q10 (mg/g), t90 (h), number of cycles (cycles) and retained removal capacity (RR) as comparison parameters.; Relatively high removal capacity were proposed.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6138af96fbc9b577d04594564d854d07
http://aqua.iwaponline.com/content/70/7/921 -
7
المصدر: Veterinary Medicine International, Vol 2021 (2021)
Veterinary Medicine Internationalمصطلحات موضوعية: Veterinary medicine, Article Subject, General Veterinary, Sorbitol-MacConkey agar, Virulence, Biology, Trimethoprim, Latex fixation test, chemistry.chemical_compound, fluids and secretions, Antibiotic resistance, chemistry, SF600-1100, medicine, Agar diffusion test, Pathogen, Cefixime, Research Article, medicine.drug
الوصف: E. coli O157:H7 is one of the most virulent foodborne pathogens. The aim of this study was to isolate E. coli O157:H7, determine virulence genes carried by the organism, and assess the antimicrobial susceptibility pattern of the isolates from beef carcass samples at Bahir Dar city. Swab samples (n = 280) were collected from the carcass of cattle slaughtered at the abattoir and processed using sorbitol MacConkey agar supplemented with cefixime telluride and confirmed with latex agglutination test. A polymerase chain reaction was performed on isolates for the detection of virulence genes stx1, stx2, hlyA, and eae. Antimicrobial susceptibility testing was performed using the disk diffusion method. Of 280 samples processed, 25 (8.9%) isolates were positive. Out of 25 isolates subjected for molecular detection, 8 (32%) and 14 (56%) isolates possessed stx1 and stx2 genes, respectively; from those, 5 (20%) isolates had both genes for the production of Shiga toxins. Compared from other virulent genes relatively higher proportion of 18 (72%) isolates carried the hlyA gene. Only 5 (2%) isolates were positive for eae. Resistance was detected in all 25 (100%) isolates and 3 (12%) against clindamycin and trimethoprim, respectively. This study result highlights the potential threat to public health. The abattoir workers need to be aware about the pathogen and should follow appropriate practices to prevent contamination of meat intended for human consumption.
وصف الملف: text/xhtml
-
8
المؤلفون: Zenebe Negeri, Solomon Tesfaye, Niguse Hamba, Asfaw Gerbi
المصدر: Alexandria Journal of Medicine; Vol. 57 No. 1 (2021); 157-167
مصطلحات موضوعية: formaldehyde, occupational exposure, detrimental health effects, antioxidants, oxidative tissue damage, business.industry, fungi, Formaldehyde, food and beverages, 030209 endocrinology & metabolism, General Medicine, Systemic health, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Immune system, chemistry, Immunology, Medicine, 030212 general & internal medicine, Occupational exposure, business, Beneficial effects, FORMALDEHYDE EXPOSURE
الوصف: Background: Formaldehyde (FA) is a sensitizing agent that can produce an effective immune system response upon initial exposure. FA that can be used in many industries, medical and anatomical facilities, mainly cadaver-based gross anatomy laboratories, represent a risk to occupational health of professionals and students. The majority of FA exposures occur through inhalation, dermal, and eye contact. FA-induced effects are attributed to site-specific and dosedependent health impairments in many organs and organ systems. Much progress has been reported on FA-induced health impairments in respiratory tract, but a comprehensive study in different organ systems and the reverse effects of some novel antioxidants is still lacking. This review explores the cytotoxic effects of FA and its role as key signaling molecule, site specific and or dose dependent effects of FA in nasal cavity, carcinogenic effects of FA exposure in nasopharynx, effects of FA in lung macrophage functions and development of pulmonary fibrosis, dose dependent reproductive and genetic effects of FA, neurotoxic effects of FA and potential risk of FA in some beauty salons and cosmetic products. In addition, this study shows the counteracting beneficial role of melatonin, Nigella sativa, rose oils, caffeic acid phenethyl ester (CAPE), vitamin E, and proanthocyanidins (PAs) against FA induced tissue damage.Methods: A comprehensive literature search highlighting the health impairments of FA and counteracting beneficial effects of promising antioxidants was conducted using PubMed, Google Scholar, and Medline Cochrane, to assemble relevant publications from open access international journals published only in English.Results: The search generated 411 articles of which 70 full research articles fulfilled the inclusion criteria and included in the review. The results of this study confirmed relentless toxic effects of FA exposure on various organs of human and other animals. Multiple findings also stated the efficacy of promising antioxidants against FA-induced tissue damage in animal models.Conclusion: Occupational exposure to FA is most likely due to inattention towards its side effects and lack of appropriate air filtering equipment or unmonitored concentration of FA in the working air. Therefore, re-evaluating the concentration of FA, proper ventilation, and assessment of working practices is highly recommended. Proper monitoring is also needed to improve compliance and protection of FA-based reproductive complications in females. Despite complete prevention is not viable, exposed personnel must be aware of FA-induced health effects and require assessing risks and acquiring practical measures in their working environment.
وصف الملف: application/pdf
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e11a1d91e1c85b6bdec0e0eaf6301e7e
https://www.ajol.info/index.php/bafm/article/view/232115 -
9
المصدر: Genetic Resources and Crop Evolution. 68:279-293
مصطلحات موضوعية: 0106 biological sciences, 0301 basic medicine, Veterinary medicine, Genetic diversity, education.field_of_study, Phylogenetic tree, Population, Plant Science, Biology, 01 natural sciences, Analysis of molecular variance, 03 medical and health sciences, chemistry.chemical_compound, 030104 developmental biology, chemistry, Molecular marker, Genetics, Genetic variability, Allele, education, Agronomy and Crop Science, Neighbor joining, Ecology, Evolution, Behavior and Systematics, 010606 plant biology & botany
الوصف: Rosemary (Salvia rosemarinus Schleid.) is cultivated worldwide due to its diverse uses as spice, preservative and medicine against many illnesses. Even though rosemary is widely grown in Ethiopia, the genetic diversity of available germplasms was not assessed. Therefore, this experiment was designed to analyze the genetic diversity of Ethiopian rosemary for further breeding activities. Genetic diversity of 45 rosemary accessions collected from different parts of Ethiopia was analyzed using 12 simple sequence repeat markers. A total of 189 alleles were detected, and the number of alleles per marker (Na) ranged from 7 to 27 with an average of 15.75. About 56.6% of the alleles were rare (frequency 0.5), respectively. Polymorphic information content per marker ranged from 0.74 to 0.94, with an average value of 0.87. The result depicted over all polymorphism of 92.6%, indicating the existence of high genetic variability among the accessions. The average values of expected (HE) and observed (HO) heterozygosities were 0.65 and 0.35, respectively. The average HO was lower than HE, showed heterozygote deficiency due to restricted cross-fertilization. Analysis of molecular variance revealed that within populations variations contributed more to the genetic diversity than between population variations. Unweighted Neighbor Joining based phylogenetic analysis, Principal Coordinate analysis and STRUCTURE analysis showed admixture of the populations, confirming that the sample groupings did not strictly follow the geographic origin of the accessions. Therefore, improvement program of the crop should focus on actual diversity, not on area of growing.
-
10
المؤلفون: Degefu Natanim, Gabriel Tesfaye, Gebre-Mariam Tsige, Belete Anteneh
المصدر: Ethiopian Pharmaceutical Journal. 36:81-96
مصطلحات موضوعية: Pharmacology, Microcrystalline cellulose, Hydrolysis, chemistry.chemical_compound, Thermogravimetric analysis, Crystallinity, chemistry, Hausner ratio, Pharmaceutical Science, Cellulose, Degree of polymerization, Bagasse, Nuclear chemistry
الوصف: Cellulose, the most abundant biomass material in nature finds wide applications in the pharmaceutical industry. Sugarcane bagasse (SCB) is one of the main agricultural lignocellulose byproducts. The objective of this study was to prepare and characterize native and microcrystalline cellulose (MCC) from SCB and evaluate the MCC as a directly compressible pharmaceutical excipient. Cellulose was extracted from SCB by chlorine-free methods with or without dewaxing. MCC was prepared from the cellulose by hydrolysis using hydrochloric acid, and subsequently oven-dried (OD) or spray-dried (SD). The as-obtained cellulose and MCC were characterized in terms of yield, degree of polymerization (DP), chemical functionality, crystallinity, morphology and thermal stability. The chemical composition, particle size, densities and direct compressibility of MCCs were also determined. Cellulose yields on a dry weight basis were found to be 42.8 ± 1.10% and 43.5 ± 0.5% from non-dewaxed and dewaxed SCB, respectively. Dewaxed SCB cellulose (DSCBC) provided higher yield of MCC (DSCB-MCCOD, 83 ± 0.74%) than non-dewaxed SCB cellulose (SCBC) (SCB-MCCOD; 78 ± 1.07%). The DP of SCBC and DSCBC were 580.56 and 592.75, respectively, while the DP of MCC ranged from 230.10 - 251.40. The FTIR spectra of both cellulose and MCC were similar with that of Avicel PH-101. The degree of crystallinity of the dewaxed cellulose (77.34%) and MCCOD (79.56%) and MCC-SD (81.87%) were higher than non-dewaxed cellulose (74.50%) and MCC-OD (78.11%) and MCC-SD (79.62%). Scanning electron micrographs (SEM) showed a fibrous structure for DSCBC and rod-shaped for DSCB-MCC. Thermogravimetric analysis (TGA) revealed dewaxed products exhibited better thermal stability than non-dewaxed products. All MCC samples exhibited monomodal normal particle size distributions. The Hausner ratio and Carr’s index of DSCB-MCCOD and Avicel PH-101 were not significantly different (p < 0.05) indicating similar flow property and compressibility of the materials, respectively. Also, plain tablets prepared from SCB-MCC showed reasonably high crushing strengths (MCC-SD > MCC-OD), although tablets of Avicel PH-101 showed the highest crushing strengths. Thus, SCB could be an alternative source of cellulose and MCC for pharmaceutical applications.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::b00a03638f47a51a5c562a2cd66801be
https://doi.org/10.4314/epj.v36i2.2
إعادة تعيين المنقحات
عرض المنقحات (%%عد%%)
PDF full text from Publisher