389,895 research outputs found
Delignification by Using Alkaline-acid Pretreatment on Bioethanol Production From Rice Straw
Rice straw as agricultural waste contains cellulose that potentially to produce ethanol. However, it has lignin content that will inhibit the enzyme in converting glucose into ethanol. In this research, pretreatment steps aim to release and breakdown lignin in rice straw. Pretreatment was conducted in two phases, alkaline pretreatment using NaOH (1%,2%,3%,4%,and 5%) and acid pretreatment using 1% H2SO4 with various heating time (30, 60, 90, 120 and 150 minutes) and used for ethanol production by means of Simultaneous Saccharification and Fermentation (SSF) with cellulose enzyme and Saccharomyces Cerevisiae. The results showed that higher NaOH concentration using on alkaline pretreatment and longer heating time on acid pretreatment made morbe degraded lignin content. The highest ethanol content produced was 48.38% from delignification treatment with NaOH concentration of 5% and acid pretreatment time of 150 minutes
Heat-shock pretreatment inhibits sorbitol-induced apoptosis in K562, U937 and HeLa cells.
The aim of this study was to determine whether heat-shock pretreatment
exerted a protective effect against sorbitol-induced apoptotic
cell death in K562, U937 and HeLa cell lines and whether
such protection was associated with a decreased cytochrome c
release from mithocondria and a decreased activation of caspase-9
and -3. Following heat-shock pretreatment (42 6 0.3C for 1 hr),
these cell lines were exposed to sorbitol for 1 hr. Apoptosis was evaluated
by DNA fragmentation, whereas caspase-9,-3 activation, cytochrome
c release and heat-shock protein70 (HSP70) were assayed
by Western Blot. Sorbitol exposure-induced apoptosis in these different
cell lines with a marked activation of caspase-9 and caspase-
3, whereas heat-shock pretreatment before sorbitol exposure,
induced expression of HSP70 and inhibited sorbitol-mediated cytochrome
c release and subsequent activation of caspase-9 and caspase-
3. Similarly, overexpression of HSP70 in the three cell lines
studied prevented caspase-9 cleavage and activation as well as cell
death. Furthermore, we showed that the mRNA expression of iNOS
decreased during both the heat-shock treatment and heat-shock
pretreatment before sorbitol exposure. By contrast, the expression
of Cu-Zn superoxide dismutase (SOD) and Mn-SOD proteins
increased during heat-shock pretreatment before sorbitol exposure.
We conclude that, heat-shock pretreatment protects different cell
lines against sorbitol-induced apoptosis through a mechanism that
is likely to involve SOD family members
Enhancement of microalgae anaerobic digestion by thermo-alkaline pretreatment with lime (CaO)
The aim of this study was to evaluate for the first time the effect of a thermo-alkaline pretreatment with lime (CaO) on microalgae anaerobic digestion. The pretreatment was carried out by adding different CaO doses (4 and 10%) at different temperatures (room temperature (25 °C), 55 and 72 °C). The exposure time was 4 days for pretreatments at 25 °C, and 24 h for pretreatments at 55 and 72 °C. Following, a biochemical methane potential test was conducted with pretreated and untreated microalgae. According to the results, the pretreatment enhanced proteins solubilisation by 32.4% and carbohydrates solubilisation by 31.4% with the highest lime dose and temperature (10% CaO and 72 °C). Furthermore, anaerobic digestion kinetics were improved in all cases (from 0.08 to 0.14 day- 1 for untreated and pretreated microalgae, respectively). The maximum biochemical methane potential increase (25%) was achieved with 10% CaO at 72 °C, in accordance with the highest biomass solubilisation. Thus, lime pretreatment appears as a potential strategy to improve microalgae anaerobic digestion.Peer ReviewedPostprint (author's final draft
The effects of pretreatment conditions on a Pt/SnO2 catalyst for the oxidation of CO in CO2 lasers
CO oxidation catalysts with high activity at 25 to 100 C are important for long life, closed cycle operation of pulsed CO2 lasers. A reductive pretreatment with either CO or H2 was shown to significantly enhance the activity of a commercially available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment of no pretreatment. Pretreatment at temperatures of 175 C and above causes an initial dip in the observed CO2 yield before the steady state yield is attained. This dip was found to be caused by dehydration of the catalyst during pretreatment and is readily eliminated by humidifying the catalyst or the reaction gas mixture. It is hypothesized that the effect of humidification is to increase the concentration of OH groups on the catalyst surface which play a role in the reaction mechanism
Pretreatment of secondary effluents in view of optimal ozone-based AOP removal of trace organic contaminants : bench-scale comparison of efficiency and energy consumption
This study compares the performance of several ozone-based advanced oxidation processes (AOPs), in combination with filtration, in terms of trace organic contaminant (TrOC) removal efficiency and energy and cost requirement. It was shown that the hydroxyl radical ((OH)-O-center dot) scavenging rate of the secondary wastewater effluent decreased as a result of an additional pretreatment step, leading to an increase of ozone and (OH)-O-center dot exposures at the same ozone dose. Adding filtration such as sand filtration or granular activated carbon filtration (GACF) as a pretreatment increased the removal efficiency of TrOCs by all tested ozone-based AOPs and reduced the minimum effective ozone dose for TrOC elimination. When the applied ozone dose is more than this minimum effective ozone dose, the elimination of TrOCs can be observed. For example, because of the use of anion resin filtration, 17 alpha-ethinylestradiol elimination contributed by the process of ozone-based AOP increased from 34.6 to 42.1% at an ozone dose of 1.0 g O-3/g dissolved organic carbon. Ozone-based AOPs coupled with filtration as a pretreatment were found to be more cost-efficient than the single AOPs at all ozone dose levels. The energy consumption of ozone-based AOPs was decreased by more than 25% when applying GACF as a pretreatment. In comparison with other filtration techniques, the pretreatment of secondary effluents by GACF before ozonation was proven to be the most cost-effective method for TrOC elimination
Thoracic duct drainage in organ transplantation: Will it permit better immunosuppression?
It is possible that thoracic-duct drainage, a major but neglected immunosuppressive adjunct, can have an important impact on organ transplantation. If thoracic-duct drainage is started at the time of transplantation, the practicality of its use in cadaveric cases is greatly enhanced. With kidney transplantation, the penalty of not having pretreatment for the first organ is compensanted by the automatic presence of pretreatment if rejection is not controlled and retransplantation becomes necessary. The advantage of adding thoracic-duct drainage to conventional immunosuppression may greatly enhance the expectations for the transplantation of extrarenal organs, such as the liver, pancreas, heart, and lung. There is evidence that pretreatment with thoracic-duct drainage of patients with cytotoxic antibodies may permit successful renal transplantation under these otherwise essentially hopeless conditions. Exploration of the neglected but potentially valuable tool of thoracic-duct drainage seems to the authors to be highly justified in other centers
Effects of propidium monoazide (PMA) treatment on mycobiome and bacteriome analysis of cystic fibrosis airways during exacerbation
Introduction and Purpose : Propidium monoazide (PMA)-pretreatment has increasingly been applied to remove the bias from dead or damaged cell artefacts, which could impact the microbiota analysis by high-throughput sequencing. Our study aimed to determine whether a PMA-pretreatment coupled with high-throughput sequencing analysis provides a different picture of the airway mycobiome and bacteriome.
Results and Discussion : We compared deep-sequencing data of mycobiota and microbiota of 15 sputum samples from 5 cystic fibrosis (CF) patients with and without prior PMA-treatment of the DNA-extracts. PMA-pretreatment had no significant effect on the entire and abundant bacterial community (genera expressed as operational taxonomic units (OTUs) with a relative abundance greater than or equal to 1%), but caused a significant difference in the intermediate community (less than 1%) when analyzing the alpha biodiversity Simpson index (p = 0.03). Regarding PMA impact on the airway mycobiota evaluated for the first time here; no significant differences in alpha diversity indexes between PMA-treated and untreated samples were observed. Regarding beta diversity analysis, the intermediate communities also differed more dramatically than the total and abundant ones when studying both mycobiome and bacteriome. Our results showed that only the intermediate (or low abundance) population diversity is impacted by PMA-treatment, and therefore that abundant taxa are mostly viable during acute exacerbation in CF. Given such a cumbersome protocol (PMA-pretreatment coupled with high-throughput sequencing), we discuss its potential interest within the follow-up of CF patients. Further studies using PMA-pretreatment are warranted to improve our "omic" knowledge of the CF airways
670 nm light mitigates oxygen-induced degeneration in C57BL/6J mouse retina
BACKGROUND Irradiation with light wavelengths from the far red (FR) to the near infrared (NIR) spectrum (600 nm -1000 nm) has been shown to have beneficial effects in several disease models. In this study, we aim to examine whether 670 nm red light pretreatment can provide protection against hyperoxia-induced damage in the C57BL/6J mouse retina. Adult mice (90-110 days) were pretreated with 9 J/cm2 of 670 nm light once daily for 5 consecutive days prior to being placed in hyperoxic environment (75% oxygen). Control groups were exposed to hyperoxia, but received no 670 nm light pretreatment. Retinas were collected after 0, 3, 7, 10 or 14 days of hyperoxia exposure (n = 12/group) and prepared either for histological analysis, or RNA extraction and quantitative polymerase chain reaction (qPCR). Photoreceptor damage and loss were quantified by counting photoreceptors undergoing cell death and measuring photoreceptor layer thickness. Localization of acrolein, and cytochrome c oxidase subunit Va (Cox Va) were identified through immunohistochemistry. Expression of heme oxygenase-1 (Hmox-1), complement component 3 (C3) and fibroblast growth factor 2 (Fgf-2) genes were quantified using qPCR. RESULTS The hyperoxia-induced photoreceptor loss was accompanied by reduction of metabolic marker, Cox Va, and increased expression of oxidative stress indicator, acrolein and Hmox-1. Pretreatment with 670 nm red light reduced expression of markers of oxidative stress and C3, and slowed, but did not prevent, photoreceptor loss over the time course of hyperoxia exposure. CONCLUSION The damaging effects of hyperoxia on photoreceptors were ameliorated following pretreatment with 670 nm light in hyperoxic mouse retinas. These results suggest that pretreatment with 670 nm light may provide stability to photoreceptors in conditions of oxidative stress.This work was supported by the Australian Research Council Centre of Excellence in Vision Science
Argon plasma treatment techniques on steel and effects on diamond-like carbon structure and delamination
Copyright © 2011 Elsevier B.V. All rights reserved.We demonstrate alteration in diamond-like carbon (DLC) film structure, chemistry and adhesion on steel, related to variation in the argon plasma pretreatment stage of plasma enhanced chemical vapour deposition. We relate these changes to the alteration in substrate structure, crystallinity and chemistry due to application of an argon plasma process with negative self bias up to 600 V. Adhesion of the DLC film to the substrate was assessed by examination of the spallated fraction of the film following controlled deformation. Films with no pretreatment step immediately delaminated. At 300 V pretreatment, the spallated fraction is 8.2%, reducing to 1.2% at 450 V and 0.02% at 600V. For bias voltages below 450V the adhesion enhancement is explained by a reduction in carbon contamination on the substrate surface, from 59at.% with no treatment to 26at.% at 450V, concurrently with a decrease in the surface roughness, Rq, from 31.5nm to 18.9nm. With a pretreatment bias voltage of 600V a nanocrystalline, nanostructured surface is formed, related to removal of chromium and relaxation of stress; X-ray diffraction indicates this phase is incipient at 450V. In addition to improving film adhesion, the nanotexturing of the substrate prior to film deposition results in a DLC film that shows an increase in sp3/sp2 ratio from 1.2 to 1.5, a reduction in surface roughness from 31nm to 21nm, and DLC nodular asperities with reduced diameter and increased uniformity of size and arrangement. These findings are consistent with the substrate alterations due to the plasma pretreatment resulting in limitation of surface diffusion in the growth process. This suggests that in addition to deposition phase processes, the parameters of the pretreatment process need to be considered when designing diamond-like carbon coatings.This work is partially supported by the Technology Strategy Board, reference BD266E
Research of influence of technological processing parameters of protein-fat base for supply of sportsmen on activity of protease inhibitors
The object of research is the biological value of the protein-fat base for athletes, workers of heavy physical labor, military personnel, depending on the conditions of its preliminary processing. A technological audit, the purpose of which was to determine the change in the content of amino acids after enzymatic hydrolysis in samples of the protein-fat base, that had undergone pretreatment by microwave radiation, was conducted. The effectiveness of the protein-fat base pretreatment by microwave radiation was evaluated on the amount of α-amino nitrogen after enzymatic hydrolysis. Based on the analysis of the obtained data, the optimal conditions of the protein-fat base pretreatment were established: 250–350 seconds of microwave treatment time and its hydration to the 12–14 % of moisture content. Such processing will increase the biological value of the protein-fat base, namely, increase the degree of digestion and digestibility of proteins in the gastrointestinal tract
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