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A peptidase S9 prolyl oligopeptidase domain from Thermotoga petrophila RKU-1T (TpS9) was over-expressed as an active, soluble and hyperstable lipolytic enzyme in the mesophilic host system. The sequence analysis demonstrated, TpS9 is an esterase/lipase-like protein belongs to alpha/beta (α/ß)-hydrolase superfamily with a well-conserved penta-peptide (GLSAG) motif and α/ß-hydrolase fold. Various approaches (induction and cultivation) were employed to enrich TpS9 production, 6.04- and 7.26-fold increment was observed with IPTG (0.4 mM) and lactose (200 mM) in the modified 4ZB medium (pH 7.0), but with IPTG-independent auto-induction strategy 9.02-fold augmentation was achieved after 16 h incubation at 24 °C (150 rev min-1). Purified TpS9 showed optimal activity in McIlvaine buffer (pH 6.5) at 80-85 °C, and revealed great thermal (30-85 °C) and pH (6.0-9.0) for 8 h. No obvious constraint was perceived with various metal ions, surfactants, commercial laundry detergents, and chemical modulators. Whereas, TpS9 activity was improved with Ca2+, Mn2+, and Mg2+ by 210 %, 142.5 %, and 134.3 %, respectively. With 2.5 M NaCl (215 %), 50 % (v/v) methanol (140 %), 50 % (v/v) ethanol (126.6 %), 50 % (v/v) n-butanol (122.3 %), 50 % (v/v) isopropanol (120.4 %), 50 % (v/v) acetone (118.6 %) and 50 % (v/v) glycerol (113.2 %) TpS9 activity was also enriched. TpS9 demonstrated great affinity toward natural oils and p-nitrophenyl ester substrates, but showed peak activity with p-nitrophenyl palmitate (3160 U mg-1). Km, Vmax, kcat, Vmax Km-1 and kcat Km-1 of TpS9 with pNPP were 0.421 mM, 4015 µmol mg-1 min-1, 906.4 s-1, 9536.8 min-1, and 2152.96 mM-1 s-1, respectively. Moreover, TPS9 has notable ability to clean stains (5 min) and degrade the animals' fat (3 h). Hence, TpS9 is a favorable candidate as cleaning bio-additive in detergent formulation, fat degradation and various other applications.
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Detergentes , Lipase , Lipase/metabolismo , Lipase/química , Detergentes/química , Detergentes/farmacologia , Estrutura Molecular , Estabilidade Enzimática , Temperatura , Relação Estrutura-Atividade , Concentração de Íons de HidrogênioRESUMO
Synthetic pollutants are a looming threat to the entire ecosystem, including wildlife, the environment, and human health. Polyhydroxyalkanoates (PHAs) are natural biodegradable microbial polymers with a promising potential to replace synthetic plastics. This research is focused on devising a sustainable approach to produce PHAs by a new microbial strain using untreated synthetic plastics and lignocellulosic biomass. For experiments, 47 soil samples and 18 effluent samples were collected from various areas of Punjab, Pakistan. The samples were primarily screened for PHA detection on agar medium containing Nile blue A stain. The PHA positive bacterial isolates showed prominent orange-yellow fluorescence on irradiation with UV light. They were further screened for PHA estimation by submerged fermentation in the culture broth. Bacterial isolate 16a produced maximum PHA and was identified by 16S rRNA sequencing. It was identified as Stenotrophomonas maltophilia HA-16 (MN240936), reported first time for PHA production. Basic fermentation parameters, such as incubation time, temperature, and pH were optimized for PHA production. Wood chips, cardboard cutouts, plastic bottle cutouts, shredded polystyrene cups, and plastic bags were optimized as alternative sustainable carbon sources for the production of PHAs. A vital finding of this study was the yield obtained by using plastic bags, i.e., 68.24 ± 0.27%. The effective use of plastic and lignocellulosic waste in the cultivation medium for the microbial production of PHA by a novel bacterial strain is discussed in the current study.
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Biodegradação Ambiental , Biomassa , Poli-Hidroxialcanoatos/biossíntese , Resíduos , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Reatores Biológicos , Fermentação , Humanos , Concentração de Íons de Hidrogênio , Plásticos , RNA Ribossômico 16S , TemperaturaRESUMO
BACKGROUND: In the present-day world, the aging elderly across the world are living longer. Most people are expected to live well into their sixties and even beyond. The increasing life expectancy of the aging population could be due to increased availability of healthcare facilities and improved quality care provided by them. Alongside increasing life expectancy, the individual's quality of life and also his/her oral health-related quality of life (OHR-QoL) are expected to improve so that they can enjoy their aging life. AIM AND OBJECTIVE: The aim of this review article is to highlight aging-related oral health changes and their impact on the individual's quality of life. REVIEW RESULTS: Age-related oral changes are seen in the tooth structure making the enamel more brittle resulting in severe attrition. Autoimmune diseases like Sjogren's syndrome are followed by decrease in the salivary gland function and the reason is unknown, and medications like antihypertensive and analgesics are associated with the decrease in salivary flow, which increases the patient's risk of developing dental caries, and also make the oral tissues more prone to mucosal infections. Edentulism has also been directly related to masticatory problems and nutritional problems. The studies reported on OHR-QoL of these frail elderly populations have shown lower scores. CONCLUSION: It is important for health professionals, especially those dealing with these frail elderly populations, to have a better understanding of their dental needs and also understand the physiologic changes undergone by them. The health professionals should understand and comprehend the oral health challenges these vulnerable people face. CLINICAL SIGNIFICANCE: Healthcare providers should conduct periodic oral examinations along with general examination and should avoid prescribing medications that have xerostomia as a side effect. The elderly individuals should be encouraged to keep their mouth moist using water or artificial saliva and maintain good oral and denture hygiene.
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Cárie Dentária , Xerostomia , Idoso , Envelhecimento , Feminino , Idoso Fragilizado , Humanos , Masculino , Saúde Bucal , Qualidade de Vida , Xerostomia/epidemiologiaRESUMO
OBJECTIVE: To review the dynamics of neuroscience research in the Kingdom of Saudi Arabia (KSA) from 2013-2018. METHODS: Subject category of Neuroscience was selected in the SciVal feature of Scopus database, which includes all relevant categories of the field limiting it to Saudi Arabia. RESULTS: Saudi Arabia is ranked 39th in publishing neuroscientific research worldwide. The number of yearly published articles has increased from 123 to 332 during the time period between 2013 and 2018. King Saud University & King Abdul Aziz University & their corresponding regions namely Western and Central regions are the major contributors to publications. Neuroscientists working in Saudi Arabia have collaboration with scientists from all over the world. The top 10 preferred journals are all international. In subcategories of neuroscience, developmental neuroscience seems the one that needs attention. CONCLUSION: Neuroscience research is on the rise in KSA. Older and well-established institutions like King Saud University & King Abdul Aziz University have taken lead in publishing neuroscientific research. International collaboration in all subfields of neuroscience is substantial. Eastern Southern and Northern regions and developmental neuroscience require more focus and funding.
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Bibliometria , Pesquisa Biomédica , Neurociências , Publicações/estatística & dados numéricos , Humanos , Arábia SauditaRESUMO
Klebsiella pneumoniae shows increasing emergence of multidrug-resistant lineages, including strains resistant to all available antimicrobial drugs. We conducted whole-genome sequencing of 178 highly drug-resistant isolates from a tertiary hospital in Lahore, Pakistan. Phylogenetic analyses to place these isolates into global context demonstrate the expansion of multiple independent lineages, including K. quasipneumoniae.
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Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano/genética , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Adolescente , Antibacterianos/farmacologia , Criança , Criança Hospitalizada , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/isolamento & purificação , Paquistão/epidemiologia , Filogenia , Análise de Sequência de DNARESUMO
Thermostable alkaline serine protease gene of Geobacillus stearothermophilus B-1172 was cloned and expressed in Escherichia coli BL21 (DE3) using pET-22b(+), as an expression vector. The growth conditions were optimized for maximal production of the protease using variable fermentation parameters, i.e., pH, temperature, and addition of an inducer. Protease, thus produced, was purified by ammonium sulfate precipitation followed by ion exchange chromatography with 13.7-fold purification, with specific activity of 97.5 U mg(-1) , and a recovery of 23.6%. Molecular weight of the purified protease, 39 kDa, was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at 90 °C at pH 9. The enzyme activity was steady in the presence of EDTA indicating that the protease was not a metalloprotease. No significant change in the activity of protease after addition of various metal ions further strengthened this fact. However, an addition of 1% Triton X-100 or SDS surfactants constrained the enzyme specific activity to 34 and 19%, respectively. Among organic solvents, an addition of 1-butanol (20%) augmented the enzyme activity by 29% of the original activity. With casein as a substrate, the enzyme activity under optimized conditions was found to be 73.8 U mg(-1) . The effect of protease expression on the host cells growth was also studied and found to negatively affect E. coli cells to certain extent. Catalytic domains of serine proteases from eight important thermostable organisms were analyzed through WebLogo and found to be conserved in all serine protease sequences suggesting that protease of G. stearothermophilus could be beneficially used as a biocontrol agent and in many industries including detergent industry.
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Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Endopeptidases/genética , Endopeptidases/metabolismo , Geobacillus stearothermophilus/genética , 1-Butanol/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Caseínas/metabolismo , Domínio Catalítico , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Endopeptidases/química , Endopeptidases/isolamento & purificação , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Fermentação , Geobacillus stearothermophilus/enzimologia , Concentração de Íons de Hidrogênio , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Serina Proteases/química , Especificidade por Substrato , Tensoativos/farmacologia , TemperaturaRESUMO
A hyperstable lipase from Thermotoga naphthophila (TnLip) was cloned and overexpressed as a soluble and active monomeric protein in an effectual mesophilic host system. Sequence study revealed that TnLip is a peptidase S9 prolyl oligopeptidase domain (acetyl esterase/lipase-like protein), belongs to alpha/beta (α/ß)-hydrolase superfamily containing a well-conserved α/ß-hydrolase fold and penta-peptide (GLSAG) motif. Various cultivation and induction strategies were applied to improve the heterologous expression and bacterial biomass, but TnLip intracellular activity was enhanced by 14.25- fold with IPTG-independent auto-induction approach after 16 h (26 °C, 150 rev min-1) incubation. Purified TnLip (35 kDa) showed peak activity at 85 °C in McIlvaine buffer (pH 7.0-8.0), and has great stability over a broad range of pH (5.0-10.0), and temperature (40-85 °C) for 8 h. TnLip exhibited prodigious resistance toward various commercial detergents, chemical additives, and salt. TnLip activity was improved by 170.51 %, 130.67 %, 127.42 %, 126.54 %, 126.61 %, 120.32 %, and 116.31 % with 50 % (v/v) of methanol, ethanol, n-butanol, isopropanol, acetone, glycerol, and acetic acid, respectively. Moreover, with 3.0 M of NaCl, and 10 mM of Ca2+, Mn2+, and Mg2+ TnLip activity was augmented by 210 %, 185.64 %, 152.03 %, and 116.26 %, respectively. TnLip has an affinity with various substrates (p-nitrophenyl ester and natural oils) but maximal hydrolytic activity was perceived with p-nitrophenyl palmitate (pNPP, 3600 U mg-1) and olive oil (1182.05 U mg-1). The values of Km (0.576 mM), Vmax (4216 µmol mg-1 min-1), VmaxKm-1 (7319.44 min-1), kcat (1106.74 s-1), and kcatKm-1 (1921.42 mM-1 s-1) were calculated using pNPP substrate. Additionally, TnLip degraded animals' fats and removed oil stains within 3 h and 5 min, respectively. All these features make halo-alkali-thermophilic TnLip as an auspicious contender for laundry detergents (cleaning bio-additive), fat degradation, wastewater treatment and endorse eco-friendly stewardship along with various other biotechnological applications.
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Aim: This study probed into the gender variation, subject dispersion and citation impact of dental research with an objective to highlight the increasing influence of female authors in the field of dentistry. Methodology: The research employed bibliometric techniques to highlight gender variation in dental research as demonstrated in the Saudi Dental Journal (SDJ), over a period of thirteen years, 2009-2021. The examination comprised SDJ publications indexed in PubMed, with citation data extracted from Google Scholar on July 2023. The analysis encompassed the progressive growth of papers, authors, and citations, the gender distribution of authors, the co-authorship structure, subject dispersion, and collaboration patterns based on affiliation, both national and international. Results: 625 SDJ publications were identified in the PubMed database from 2009 to 2021. There was a notable rise in the volume of papers and the number of authors per year. The citation impact analysis revealed that these 625 papers achieved an average of 26 citations each. Remarkably, the representation of female authors increased from 0.47 to 2.23 authors per paper during the study period. The authorship pattern largely showed single-authorship, closely followed by a three-author pattern. Almost half the papers (48%) were a collaboration between male and female authors, with female authors solely producing about 15% of papers.The topological classification of papers revealed that the most considerable number of papers were on Periodontics, with the least number focusing on Oral and Maxillofacial Surgery. Female authors prominently contributed to Pediatric Dentistry and Periodontics papers. Conclusion: The study illustrates an encouraging trend of heightened female authorship in dental research over the years. Their increasing engagement not only enriches the academic diversity but also impacts the progressive evolution of dental science, contributing to a more inclusive and balanced society.
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OBJECTIVE: Extended-spectrum ß-lactamase producing K. pneumoniae is a serious threat to the patients. This manuscript shows the comparison of phenotypic characterization methods used for ESBL K. pneumoniae and frequency distribution of these isolates in various clinical samples. METHODOLOGY: Eleven different types of pathological samples collected on various time intervals were analyzed. K. pneumoniae were identified with API 20E system (bioMerieux) and initial screening of ESBL K. pneumoniae was performed using the ceftazidime antimicrobial disc. Double-disc synergy test (DDST) and CLSI confirmatory test were compared for the phenotypic detection of ESBL K. pneumoniae. RESULTS: A total number of 214 ESBL producing K. pneumoniae were isolated from various clinical samples. Frequency distribution of ESBL producing K. pneumoniae was found to be highest among blood 117 (54.7%) and urine 46 (21.5%) samples. Data regarding the use of various interventions among these patients showed most common presence of intravenous line 209 (97.7%) and urinary catheters 46 (21.5%). Comparison of DDST and CLSI confirmatory test showed that the DDST detected 145 (67.8%) isolates while 213 (99.5%) ESBL K. pneumoniae were characterized by CLSI confirmatory test. CONCLUSION: The use of CLSI confirmatory test is very efficient in the early detection of ESBL K. pneumoniae especially when the facilities for molecular characterization are not available.
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Objectives: The Level of Evidence (LOE) ranking system is used to measure the methodological quality of research. This study aimed to analyze and evaluate the trends of LOEs in articles published in the Saudi Dental Journal (SDJ) between 2012 and 2021. Methodology: The bibliometric details of all articles published from 2012 to 2021 were extracted from the SDJ website. All articles, expect editorials, were included in the analysis. The articles were divided based on LOEs, dental specialties, number of authors, and centers. The citation metrics were obtained from Google Scholar, and the statistical analysis was performed using JMP Pro 15.2.0 software. Results: Five hundred twenty-two articles were selected for analysis. They had an average of 21.19 citations per article, and a growing trend in the number of articles was observed. Authors from 40 countries contributed to the articles, with the most contributions from the Kingdom of Saudi Arabia. Most articles (n = 269; 51.53%) were LOE IV and V, while a low proportion (5.56%) were LOE I articles. Aside from miscellaneous articles, periodontics composed most of the LOE I studies, followed by endodontics, and oral and maxillofacial Surgery (OMFS). Orthodontics had the highest number of LOE II studies, pediatric dentistry had the most LOE IV, and prosthodontics had the most LOE V studies. No significant correlations were found between LOE and the number of authors or centers. However, a significant correlation was found in the distribution of LOE contributed by academic institutes. Conclusion: The study results highlight that most articles were LOE IV and V, whereas nominal LOE I articles were found. Furthermore, there is a need to encourage dental scientists to carry out high-quality evidence studies. Professional dental societies can play a pivotal role in this regard.
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A low temperature alkali (LTA) pretreatment method was used to treat wheat straw. In order to obtain good results, different factors like temperature, incubation time, NaOH concentration and solid to liquid ratio for the pretreatment process were optimized. Wheat straw is a potential biomass for the production of monomeric sugars. The objective of the current study was to observe the saccharification (%) of wheat straw with immobilized magnetic nanoparticles (MNPs). For this purpose, immobilized MNPs of purified ß-xylanase enzyme was used for hydrolysis of pretreated wheat straw. Wheat straw was pretreated using the LTA method and analyzed by SEM analysis. After completion of the saccharification process, saccharification% was calculated by using a DNS method. Scanning electron micrographs revealed that the hemicellulose, cellulose and lignin were partially removed and changes in the cell wall structure of the wheat straw had caused it to become deformed, increasing the specific surface area, so more fibers of the wheat straw were exposed to the immobilized ß-xylanase enzyme after alkali pretreatment. The maximum saccharification potential of wheat straw was about 20.61% obtained after pretreatment with optimized conditions of 6% NaOH, 1/10 S/L, 30 °C and 72 hours. Our results indicate the reusability of the ß-xylanase enzyme immobilized magnetic nanoparticles and showed a 15% residual activity after the 11th cycle. HPLC analysis of the enzyme-hydrolyzed filtrate also revealed the presence of sugars like xylose, arabinose, xylobiose, xylotriose and xylotetrose. The time duration of the pretreatment has an important effect on thermal energy consumption for the low-temperature alkali method.
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AIM: Periodontics is a branch of dentistry that deals with diseases of the supporting and investing structures of the teeth including the gingiva, cementum, periodontal ligament, and alveolar bone. The current study aimed to scrutinize the bibliometric indicators of the 100 most-cited articles on periodontics contributed by authors affiliated with the Arab countries. RESEARCH METHODOLOGY: The bibliometric research method was used for the 100 most-cited articles retrieved from the Scopus database on May 9, 2023. The keywords periodontitis, periodontology, gingivitis, periodontal, gingiva, and periodontium were inserted, and then the Arab countries were selected from the country's filter. The 100 most-cited articles were accessed. The bibliometric indicators such as periodic distribution of articles, their study design, nature of research, contributed by different Arab countries, international research collaboration, and author's used keywords were analyzed. Microsoft Excel version 16 (Microsoft Corporation, Washington, United States), VOSviewer (Centre for Science and Technology Studies, Leiden University, The Netherlands), and SPSS Statistics version 27 (IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp.) were used for data analysis. RESULTS: A slow progress (4.50%) was found in periodontics literature before 2000 in the Arab countries, but a significant growth (75%) was recorded during the past 10 years (January 1, 2014, to May 9, 2023). The 100 most-cited articles on periodontics by the Arab countries were published from 1995 to 2021, and these articles gained citations with an average of 92.18 citations per articles. Case-control and review studies were the preferred study designs, and periodontology and implantology were the top two subject categories. About one-third of the articles were published in the Journal of Periodontology and the Journal of Clinical Periodontology. Saudi Arabia contributed the highest number of the most-cited articles, followed by Egypt and Jordan, but the articles contributed by the United Arab Emirates were the most influential. The United States and Germany were the top-ranked countries in international research collaboration. CONCLUSION: The findings demonstrate that periodontics research increased remarkably during the past 10 years. Saudi Arabia stands not only on the topmost rank in overall research productivity in the Arab countries but also surpasses the rest of the Arab countries in the 100 most-cited articles. Saudi Arabia contributed 26 articles with the United States, while Jordan contributed the highest ratio of indigenous research.
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The 1,044 bp endo-1,4-ß-xylanase gene of a hyperthermophilic Eubacterium, "Thermotoga petrophila RKU 1" (T. petrophila) was amplified, from the genomic DNA of donor bacterium, cloned and expressed in mesophilic host E. coli strain BL21 Codon plus. The extracellular target protein was purified by heat treatment followed by anion and cation exchange column chromatography. The purified enzyme appeared as a single band, corresponding to molecular mass of 40 kDa, upon SDS-PAGE. The pH and temperature profile showed that enzyme was maximally active at 6.0 and 95 °C, respectively against birchwood xylan as a substrate (2,600 U/mg). The enzyme also exhibited marked activity towards beech wood xylan (1,655 U/mg). However minor activity against CMC (61 U/mg) and ß-Glucan barley (21 U/mg) was observed. No activity against Avicel, Starch, Laminarin and Whatman filter paper 42 was observed. The K(m), V(max) and K (cat) of the recombinant enzyme were found to be 3.5 mg ml(-1), 2778 µmol mg(-1)min(-1) and 2,137,346.15 s(-1), respectively against birchwood xylan as a substrate. The recombinant enzyme was found very stable and exhibited half life (t(½)) of 54.5 min even at temperature as high as 96 °C, with enthalpy of denaturation (ΔH*(D)), free energy of denaturation (ΔG*(D)) and entropy of denaturation (ΔS*(D)) of 513.23 kJ mol(-1), 104.42 kJ mol(-1) and 1.10 kJ mol(-1)K(-1), respectively at 96 °C. Further the enthalpy (ΔH*), Gibbs free energy (ΔG*) and entropy (ΔS*) for birchwood xylan hydrolysis by recombinant endo-1,4-ß-xylanase were calculated at 95 °C as 62.45 kJ mol(-1), 46.18 kJ mol(-1) and 44.2 J mol(-1) K(-1), respectively.
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Clonagem Molecular , Endo-1,4-beta-Xilanases/metabolismo , Bacilos Gram-Negativos Anaeróbios Retos, Helicoidais e Curvos/enzimologia , Bacilos Gram-Negativos Anaeróbios Retos, Helicoidais e Curvos/genética , Xilanos/metabolismo , Sequência de Aminoácidos , DNA Bacteriano/genética , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/genética , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Amplificação de Genes , Expressão Gênica , Bacilos Gram-Negativos Anaeróbios Retos, Helicoidais e Curvos/metabolismo , Hidrólise , Imidas/metabolismo , Morfolinas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Termodinâmica , beta-Glucanas/metabolismoRESUMO
Sensing mechanisms of gases on solid structures are predominantly surface-dominated. Benign surface features in terms of small grain size, high aspect ratio, large surface area and open and connected porosity, are required to realize a successful sensor material. Such morphological artifacts are a function of the fabrication and processing techniques employed. In this paper, we describe the fabrication of monoshaped and monosized zinc oxide (ZnO) particles by a homogeneous precipitation method, using urea and/or hexmethyltetraamine as the reductant. The effect of operating conditions and experimental variables, such as the relative concentration of the precursors, temperature, and the aging time on the morphology of the resulting particles was studied systematically. These experimental parameters were optimized in order to achieve particles of uniform morphology and of narrow size distribution. Some of these particles were employed for the detection of ammonia gas at room temperature.
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OBJECTIVES: The appraisal of research productivity is one of the key indicators to evaluate any area of knowledge. The current study aimed to analyze the Scopus-indexed publications on endodontics produced by Gulf Cooperation Council (GCC) region from 2000 to 2020. METHODOLOGY: The dataset was extracted in May 2021 from Elsevier's Scopus database. Two keywords ("endodontic" and "endodontics") were entered into the basic search with the Boolean operator of OR for a period of 20 years from 2000 to 2020. RESULTS: Overall, the GCC region contributed 2.82% of the global endodontic research. This share has shown a remarkable increase between 2001 and 2020 from 0.82% to 7.20%. About 60% of documents' volumes were produced during the 2016-2020 period. Around 80% of research was produced by Saudi Arabia, while research articles produced by Kuwait gained the highest citation impact. Out of the ten productive institutions, nine belonged to Saudi Arabia and one was from Kuwait. The majority of research collaboration was conducted with the United States, but research articles produced in collaboration with Japan yielded the highest citation impact. CONCLUSION: The study highlighted various scientometric attributes of endodontic publications produced by GCC affiliated researchers. The ongoing growth of endodontic literature by GCC countries along with the increasing international collaboration is considered aspiring.
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The antidiarrheal effect of methanolic extract of Trillium govanianum Wall. ex D. Don (Melanthiaceae alt. Trilliaceae) was studied at doses of 12.5, 25, and 50 mg/kg in different animal models of diarrhea including castor oil (6 mL/kg), magnesium sulfate (2 gm/kg), sodium picosulfate (2 mL/kg) and lactitol (0.25 mL/kg). The antispasmodic effect of T. govanianum was studied on isolated rabbit's jejunum, using acetylcholine as tissue stabiliser and verapamil as calcium channel blocker. T. govanianum attenuated the diarrhea by producing a significant decrease in the number and weight of stool, and an increase in stool latency time. T. govanianum completely inhibited both spontaneous as well as high potassium induced contractions of isolated rabbit's jejunum, which was analogous to verapamil. Moreover, T. govanianum produced a right shift in calcium concentration response curve, confirming its calcium channel blocking activity. These findings provide scientific ground to its medicinal use in diarrhea and gut spasms.
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Antidiarreicos , Trillium , Animais , Antidiarreicos/farmacologia , Cálcio , Canais de Cálcio/farmacologia , Canais de Cálcio/uso terapêutico , Diarreia/tratamento farmacológico , Jejuno/fisiologia , Parassimpatolíticos/farmacologia , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Coelhos , Rizoma , Verapamil/farmacologia , Verapamil/uso terapêuticoRESUMO
The ß-xylanase gene (DCE06_04615) with 1041 bp cloned from Thermotoga naphthophila was expressed into E. coli BL21 DE3. The cloned ß-xylanase was covalently bound to iron oxide magnetic nanoparticles coated with silica utilizing carbodiimide. The size of the immobilized MNPs (50 nm) and their binding with ß-xylanase were characterized by Fourier-transform electron microscopy (FTIR) (a change in shift particularly from C-O to C-N) and transmission electron microscopy (TEM) (spherical in shape and 50 nm in diameter). The results showed that enzyme activity (4.5 ± 0.23 U per mL), thermo-stability (90 °C after 4 hours, residual activity of enzyme calculated as 29.89% ± 0.72), pH stability (91% ± 1.91 at pH 7), metal ion stability (57% ± 1.08 increase with Ca2+), reusability (13 times) and storage stability (96 days storage at 4 °C) of the immobilized ß-xylanase was effective and superior. The immobilized ß-xylanase exhibited maximal enzyme activity at pH 7 and 90 °C. Repeated enzyme assay and saccharification of pretreated rice straw showed that the MNP-enzyme complex exhibited 56% ± 0.76 and 11% ± 0.56 residual activity after 8 times and 13 times repeated usage. The MNP-enzyme complex showed 17.32% and 15.52% saccharification percentage after 1st and 8th time usage respectively. Immobilized ß-xylanase exhibited 96% residual activity on 96 days' storage at 4 °C that showed excellent stability.
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The prerequisite for cellulosic biochemical production from lignocellulosic materials is efficient enzymatic hydrolysis that is a complicated heterogeneous catalytic process and affected by the complex lignin-cellulose-hemicellulose network. Understanding the main influencing factors for enzymatic hydrolysis is of substantial significance to guide the design of a biorefinery process. An experimental study of the pretreatment indicated that acid pretreatment is preferable for herbaceous feedstocks. Therefore, the classic dilute sulfuric acid pretreatment was utilized to hydrolyze and remove hemicellulose from three representative types of agricultural straws at various intensities. From the enzymatic hydrolysis of residual cellulose perspective, the crystallinity index and enzyme accessibility of the pretreated materials were also mathematically correlated to hemicellulose removals, respectively. For the better insight and understanding of the mathematical logics, the linear and nonlinear kinetic models were therefore compared, and the relationship was established by the five-parameter logistic equations and Allosteric sigmoidal models with well fittings.
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Celulose , Ácidos Sulfúricos , Hidrólise , LigninaRESUMO
Long-term potentiation (LTP) and long-term depression (LTD) are the current models of synaptic plasticity and widely believed to explain how different kinds of memory are stored in different brain regions. Induction of LTP and LTD in different regions of brain undoubtedly involve trafficking of AMPA receptor to and from synapses. Hippocampal LTP involves phosphorylation of GluR1 subunit of AMPA receptor and its delivery to synapse whereas; LTD is the result of dephosphorylation and endocytosis of GluR1 containing AMPA receptor. Conversely the cerebellar LTD is maintained by the phosphorylation of GluR2 which promotes receptor endocytosis while dephosphorylation of GluR2 triggers receptor expression at the cell surface and results in LTP. The interplay of phosphorylation and O-GlcNAc modification is known as functional switch in many neuronal proteins. In this study it is hypothesized that a same phenomenon underlies as LTD and LTP switching, by predicting the potential of different Ser/Thr residues for phosphorylation, O-GlcNAc modification and their possible interplay. We suggest the involvement of O-GlcNAc modification of dephosphorylated GluR1 in maintaining the hippocampal LTD and that of dephosphorylated GluR2 in cerebral LTP.
Assuntos
Cerebelo/fisiologia , Hipocampo/fisiologia , Potenciação de Longa Duração/fisiologia , Depressão Sináptica de Longo Prazo/fisiologia , Receptores de AMPA/metabolismo , Acetilglucosamina/metabolismo , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular , Plasticidade Neuronal , Fosforilação , Receptores de AMPA/genética , Alinhamento de SequênciaRESUMO
BACKGROUND: Butyric acid is a platform chemical material, the production of which has been greatly stimulated by the diverse range of downstream applications in many industries. In particular, higher quality butyric acid used in food and medicine, is more dependent on microbiological production methods. Hence, the bio-oxidation of butanol to butyric acid has been identified as a promising method with good potential economic and environmental benefits. However, both butanol and butyric acid are usually intensively toxic to most microorganisms as well as the bio-oxidation pathway. To develop a green, efficient and competitive microbiological method is the primary work to overcome the bottleneck of butyric acid industry. RESULT: A combined bioprocess was designed with alternative whole-cell catalysis for butyric acid bio-conversion from butanol by Gluconobacter oxydans in a sealed-oxygen supply bioreactor (SOS). In the operation system, the escape of volatile substrates and toxic chemicals to cells can be avoided by the use of a sealed bioreactor, combined with the rejuvenation of cells by supplying energy co-factors. Finally, during a one-batch whole-cell catalysis, the utilization rate of substrate increased from 56.6 to 96.0% by the simple skill. Additionally, the techno-practical bioprocess can realize the purpose of cell-recycling technology through the rejuvenation effect of co-factor. Finally, we obtained 135.3 g/L butyric acid and 216.7 g/L sorbose during a 60-h whole-cell catalysis. This techno-practical technology provides a promising approach to promote the industrial production of butyric acid with more competitiveness. CONCLUSION: The techno-practical biotechnology has powerfully promoted the process of butyric acid production by microorganisms, especially makes up for the lack of aerobic fermentation in the industry, and surmounts the shortcomings of traditional anaerobic fermentation. At the same time, this technically practical system provides a promising approach for the promotion of the industrial production of butyric acid in a more competitive manner.