482 research outputs found
Time Dependent Surface Corrosion Analysis and Modelling of Automotive Steel Under a Simplistic Model of Variations in Environmental Parameters
This research presents time-dependent corrosion analysis of automotive steel utilised in a large military vehicle in real operating environment, followed by simulated environmental tests and simplistic surface corrosion modelling. Time-dependent surface corrosion accumulated on this specific component was observed to be approximately 250 Âĩm thick, with the identification of surface contaminants such as chlorine and sulphur. Simulated environmental tests considering temperature and relative humidity variations were performed to evaluate quantitative corrosion damage to the structure of the vehicle. The relationship of various temperatures and relative humidity with respect to time, within the context of corrosion initiation and propagation, has been presented. A mathematical model to incorporate corrosion accumulation on the surfaces derived from the simulated environmental tests is presented
Isolation and purification of membrane-bound cytochrome c from Proteus mirabilis
In the present studies, respiratory chain pathogenic bacterium, Proteus mirabilis, was investigated. In the first phase, growth profile study was performed to optimize the P. mirabilis growth. Maximum bacterial growth could be obtained between 10 â 12 h of culturing time. Down-stream processing was performed by using sonication, ultracentrifugation and detergent solubilization techniques. Partially purified respiratory contents were analyzed spectrophotometrically. Pyridine-ferrochrome and redoxspectra showed the presence of heme-c
Efficacy of different methods used for dry socket management: a systematic review
Document publicat tambÃĐ en castellà Background: dry socket is one of the most common complications occurring after the extraction of a permanent tooth, but in spite of its high incidence there is not an established treatment for this condition. Objectives: analyze the efficacy of different methods used in the management of dry socket regarding results of pain's relief and alveolar mucosa healing compared to conventional surgical treatment of curettage and saline irrigation. Material and methods: a Cochrane and PubMed-MEDLINE database search was conducted with the search terms 'dry socket', 'post-extraction complications', 'alvogyl', 'alveolar osteitis' and 'fibrynolitic alveolitis', individually and next, using the Boolean operator 'AND'. The inclusion criteria were: clinical studies including at least 10 patients, articles published from 2004 to 2014 written in English. The exclusion criteria were case reports and nonhuman studies. Results: 11 publications were selected from a total of 627. Three of the 11 were excluded after reading the full text. The final review included 8 articles: 3 prospective studies, 2 retrospective studies and 3 clinical trials. They were stratified according to their level of scientific evidence using the SORT criteria (Strenght of Recommendation Taxonomy). Conclusions: all treatments included in the review have the aim to relief patient's pain and promote alveolar mucosa healing in dry socket. Given the heterogeneity of interventions and the type of measurement scale, the results are difficult to compare. Curettage and irrigation should be carried out in dry socket, as well as another therapy such as LLLT, zinc oxide eugenol or plasma rich in growth factors, which are the ones that show better results in pain remission and alveolar mucosa healing. Assessment alveolar bone esposure must be a factor to consider in future research. Taking into account the scientific quality of the articles evaluated, a level B recommendation is given for therapeutic interventions proposed for the treatment of dry socket
Molecular basis of arsenite (As+3)-induced acute cytotoxicity in human cervical epithelial carcinoma cells
Background: Rapid industrialization is discharging toxic heavy metals into the environment, disturbing human health in many ways and causing various neurologic, cardiovascular, and dermatologic abnormalities and certain types of cancer. The presence of arsenic in drinking water from different urban and rural areas of the major cities of Pakistan, for example, Lahore, Faisalabad, and Kasur, was found to be beyond the permissible limit of 10 parts per billion set by the World Health Organization. Therefore the present study was initiated to examine the effects of arsenite (As+3) on DNA biosynthesis and cell death.Methods: After performing cytotoxic assays on a human epithelial carcinoma cell line, expression analysis was done by quantitative polymerase chain reaction, western blotting, and flow cytometry.Results: We show that As+3 ions have a dose- and time-dependent cytotoxic effect through the activation of the caspase-dependent apoptotic pathway. In contrast to previous research, the present study was designed to explore the early cytotoxic effects produced in human cells during exposure to heavy dosage of As+3 (7.5 Ξg/ml). Even treatment for 1 h significantly increased the mRNA levels of p21 and p27 and caspases 3, 7, and 9. It was interesting that there was no change in the expression levels of p53, which plays an important role in G2/M phase cell cycle arrest.Conclusion: Our results indicate that sudden exposure of cells to arsenite (As+3) resulted in cytotoxicity and mitochondrial-mediated apoptosis resulting from up-regulation of caspases.Keywords: apoptosis; epithelial carcinoma; cytotoxicity; arsenite; caspases; Pakistan Responsible Editor: Amin Bredan, VIB Inflammation Research Center & Ghent University, Belgium
Life Cycle Assessment Studies of Jatropha (Jatropha curcas) Biodiesel Production Processed by In-situ Transesterification Method
In situ transesterification is a biodiesel production method that utilizes the original lipid-bearing agricultural products instead of purified oil as the source of triglycerides for direct transesterification. This method will eliminate the costly extraction process and reduce the long production system associated with pre-extracted oil and maximize alkyl ester yield. In this paper the production of fatty acid methyl ester (FAME) by direct in situ alkaline-catalyzed transesterification of the triglycerides (TG) in jatropha seeds was investigated and its environmental performance was compared with the conventional alkali catalyzed transesterification process using LCA as a tool. In-situ transesterification process is technically offers the advantages of the production of non-toxic jatropha seed cakes. The seed cakes after in-situ transesterification is rich in protein and is a potential source of livestock feed. However, it still generates significantly higher environmental load since in-situ transestrification needs large amount of methanol and longer duration of process. A large amount of energy will be required in methanol recovery unit
Charge injection and trapping in TiO2 nanoparticles decorated silicon nanowires arrays
We investigate carrier transport properties of silicon nanowire (SiNW) arrays decorated with TiO2 nanoparticles (NPs). Ohmic conduction was dominant at lower voltages and space charge limited current with and without traps was observed at higher voltages. Mottâs 3D variable range hoping mechanism was found to be dominant at lower temperatures. The minimum hopping distance (Rmin) for n and p-SiNWs/TiO2 NPs devices was 1.5 nm and 0.68 nm, respectively, at 77 K. The decrease in the value of Rmin can be attributed to higher carrier mobility in p-SiNWs/TiO2 NPs than that of n-SiNWs/TiO2 NPs hybrid device
Cloned genes and genetic regulation of anthocyanin biosynthesis in maize, a comparative review
Anthocyanins are plant-based pigments that are primarily present in berries, grapes, purple yam, purple corn and black rice. The research on fruit corn with a high anthocyanin content is not sufficiently extensive. Considering its crucial role in nutrition and health it is vital to conduct further studies on how anthocyanin accumulates in fruit corn and to explore its potential for edible and medicinal purposes. Anthocyanin biosynthesis plays an important role in maize stems (corn). Several beneficial compounds, particularly cyanidin-3-O-glucoside, perlagonidin-3-O-glucoside, peonidin 3-O-glucoside, and their malonylated derivatives have been identified. C1, C2, Pl1, Pl2, Sh2, ZmCOP1 and ZmHY5 harbored functional alleles that played a role in the biosynthesis of anthocyanins in maize. The Sh2 gene in maize regulates sugar-to-starch conversion, thereby influencing kernel quality and nutritional content. ZmCOP1 and ZmHY5 are key regulatory genes in maize that control light responses and photomorphogenesis. This review concludes the molecular identification of all the genes encoding structural enzymes of the anthocyanin pathway in maize by describing the cloning and characterization of these genes. Our study presents important new understandings of the molecular processes behind the manufacture of anthocyanins in maize, which will contribute to the development of genetically modified variants of the crop with increased color and possible health advantages
Effects of different altitudes on the structure and properties of potato starch
The main element influencing the quality of potato starch is the environment. To investigate the effects of different altitude cultivation locations on the molecular structure and physicochemical properties of starch, two potato varieties, Jiusen No.1 B1 and Qingshu No.9 B2, were planted in three different altitude zones: A1 at low altitude (Chongzhou 450Â m), A2 at middle altitude (Xichang 2800Â m), and A3 at high altitude (Litang 3650Â m). The results showed that the average volume, number, surface area diameter, average branched polymerization degree, crystallinity, and gelatinization temperature of two potato granules in high altitude areas were significantly lower than those in middle and low altitude areas were, and the gelatinization performance of potato starch was affected according to the correlation of starch structure characteristics. Potato starch with more short-branched chains and less long branched chains resulted in a lower gelatinization temperature in high altitude areas. The results showed that Jiusen No. 1 and Qingshu No. 9 were mainly affected by accumulated radiation and accumulated rainfall in Litang, a high altitude area, and by effective accumulated temperature in Xichang, a middle altitude area. This study quantified the influence of meteorological factors on the main starch quality of potato tubers. The results can be used as a theoretical basis for the scientific planting of high-quality potatoes
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