Methane recovery from water hyacinth through whole-cell immobilization technology

The concepts of feed pretreatment, phase separation, and whole-cell immobilization technology have been incorporated in this investigation for the development of rational and cost-effective two- and three-stage methane recovery systems from water hyacinth (WH)Analyses of laboratory data reveal that a three-stage system could be designed with an alkali pretreatment stage [3.6% Na(2)CO(3) + 2.5% Ca(OH)(2) W/W, 24 h HRT] followed by an open acid reactor (2.1 days HRT) and closed immobilized methane reactor (12 h HRT), providing steady-state COD conversion of 62-65%, TVA conversion of 91-95%, and gas productivity of 4.08-5.36 L/L reactor volume/day with 82% methane. A gas yield of 50 L/kg WH/day (dry wt basis) at 35-37 degrees C is possible with this system. Insulation bricks, with particle size distribution of 500-3000 mum, were used as support material in the reactors at organic loading rate of 20 kg COD/m(3) day. The reactors matured in 15-18 weeksSubstantial reduction in retention time for the conversion of volatile acids in immobilized methane reactors prompted further research on the combined immobilized reactor to make possible an additional reduction in the cost of a WH-based biogas system. Evaluation of laboratory data reveals that a two-stage system could be designed with an open alkali pretreatment stage and a combined immobilized reactor (12 h HRT), providing steady-state COD conversion of 53% and gas productivity of 3.1 L/L reactor volume/day with 86% methane. A gas yield of 44 L/kg WH/day (dry wt basis) at 35-37 degrees C could be obtained from this system. Insulation bricks, with 500-1000 mum particle size distribution, was used as support material at an organic loading rate of 15 kg COD/m(3) day. Notwithstanding the fact that the technology in this study has been developed with water hyacinth as substrate, the implicit principles could be extended to any other organic substrate.     

Dosimetric impact of statistical uncertainty on Monte Carlo dose calculation algorithm in volumetric modulated arc therapy using Monaco TPS for three different clinical cases

AimTo study the dosimetric impact of statistical uncertainty (SU) per plan on Monte Carlo (MC) calculation in Monaco? treatment planning system (TPS) during volumetric modulated arc therapy (VMAT) for three different clinical cases.BackgroundDuring MC calculation SU is an important factor to decide dose calculation accuracy and calculation time. It is necessary to evaluate optimal acceptance of SU for quality plan with reduced calculation time.Materials and methodsThree different clinical cases as the lung, larynx, and prostate treated using VMAT technique were chosen. Plans were generated with Monaco? V5.11 TPS with 2% statistical uncertainty. By keeping all other parameters constant, plans were recalculated by varying SU, 0.5%, 1%, 2%, 3%, 4%, and 5%. For plan evaluation, conformity index (CI), homogeneity index (HI), dose coverage to PTV, organ at risk (OAR) dose, normal tissue receiving dose ≥5 Gy and ≥10 Gy, integral dose (NTID), calculation time, gamma pass rate, calculation reproducibility and energy dependency were analyzed.ResultsCI and HI improve as SU increases from 0.5% to 5%. No significant dose difference was observed in dose coverage to PTV, OAR doses, normal tissue receiving dose ≥5 Gy and ≥10 Gy and NTID. Increase of SU showed decrease in calculation time, gamma pass rate and increase in PTV max dose. No dose difference was seen in calculation reproducibility and dependent on energy.ConclusionFor VMAT plans, SU can be accepted from 1% to 3% per plan with reduced calculation time without compromising plan quality and deliverability by accepting variations in point dose within the target.     

Site of bicarbonate effect in Hill reaction. Evidence from the use of artificial electron acceptors and donors

Using artificial electron donors and acceptors, it is shown here that the major HCO₃^? effect in the Hill reaction is after the “primary” electron acceptor (Q) of Photosystem II and before the site of action of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (at the plastoquinone pool). Chloroplasts in the presence of both 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea, which blocks electron flow from the reduced primary acceptor Q^? to the plastoquinone pool, and silicomolybdate, which accepts electrons from Q^?, show no significant bicarbonate stimulation of electron flow. However, a 6–7-fold stimulation is clearly observed when oxidized diaminodurene, as an electron acceptor, and dibromothymoquinone, as an inhibitor of electron flow beyond the plastoquinone pool, are used. In the same chloroplast preparation no measurable effect of bicarbonate is observed in a Photosystem I reaction as monitored by electron flow from reduced diaminodurene to methyl viologen in the presence of 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea. The insensitivity of the bicarbonate effect to uncouplers of photophosphorylation and the dependence of this effect on the presence of a weak acid anion and on external pH are also reported.     

Gut-associated immune effector responses in immunocompetent and immunocomprimised mice with Giardia lamblia

Abstract Significantly higher Giardia lamblia trophozoites load in the intestine of infected mice accompanied pronounced influx of suppressor/cytotoxic T cells (Lyt 2.2⁺), T cells (Thy 1.2⁺) and significant reduction in IgA-containing cells in the gut during the establishment and peak phases of infection. The induction of helper/inducer T cells (Lyt 1.1⁺) and significant enhancement of IgA-containing cells in gut resulted in the decline of the trophozoite loads. However, the prior treatment of animals with dexamethasone alone resulted in significant reduction in helper/inducer T cells (Lyt 1.1⁺) and the IgA-containing cells in the gut; the percents of suppressor/cytotoxic T cells (Lyt 2.2⁺) and IgM-containing cells remained unaltered. Although the G. lamblia infection in such animals further significantly increased the influx of suppressor/cytotoxic T cells, the late response of helper/inducer T cells and IgA-containing cells was abrogated during the decline phase of infection. The significant reduction in the trophozoite load — despite immuno-suppressive therapy — appeared to be due to unaltered IgM response in such animals which probably took over the function of IgA in defense against G. lamblia . The data of the investigation thus suggested a role of helper/inducer T cells and antibodies producing cells in gut as important effector cells resulting in the termination of primary G. lamblia infection.     

Cholesterol Diet Withdrawal Leads to an Initial Plaque Instability and Subsequent Regression of Accelerated Iliac Artery Atherosclerosis in Rabbits

Effect of long term cholesterol diet withdrawal on accelerated atherosclerosis in iliac artery of New Zealand White (NZW) rabbits has not been explored so far. Atherosclerosis was thus induced in rabbits by a combination of balloon injury and atherogenic diet (AD) (1% cholesterol and 6% peanut oil) feeding for 8 weeks (baseline) followed by chow diet (CD) feeding for 4, 8, 16, 32, 50 and 64 weeks. The plaque characterization was done using histology, real time RT-PCR and vasoreactivity studies. Significant elevation in plasma lipids with AD feeding was normalized following 16 weeks of CD feeding. However, baseline comparison showed advanced plaque features even after 8 weeks of CD period with significant elevation in intima/media thickness ratio and plaque area later showing reduction at 50 and 64 weeks CD periods. Lesion lipid accumulation and CD68 positivity was maintained till 16 weeks of CD feeding which significantly reduced from 32 to 64 weeks CD periods. Baseline comparison showed significant increase in ground substance, MMP-9 and significant decrease in α-actin and collagen content at 8 weeks CD period indicating features of unstable plaque. These features regressed up to 64 weeks of CD. Partial restoration of functional vasoconstriction and vasorelaxation was seen after 64 weeks of CD feeding. mRNA expression of MCP-1, VCAM-1, collagen type I and III, MMP-9, TIMP-1, IFN-γ, TNF-α, IL-10 and eNOS supported the above findings. The study thus reveals insights into initial plaque instability and subsequent regression on AD withdrawal in this model. These results are suggestive of an appropriate window for drug intervention for plaque stability/regression and restenosis as well as improves understanding of plaque regression phenomenon in this model.     

Trace elements (copper,zinc, selenium and molybdenum) as markers in oral sub mucous fibrosis and oral squamous cell carcinoma

Oral cancer is a major cause of cancer morbidity and mortality worldwide and is prevalent in most areas where tobacco related practices are observed. Essential elements play a role in many biochemical reactions as a micro-source and there is growing evidence that their concentrations are altered on the onset and progress of malignant disease. In this study the levels of copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo) in serum of patients with oral sub mucous fibrosis (OSMF) (n = 30) and oral squamous cell carcinoma (OSCC) (n = 30); were determined and the alterations of these critical parameters were analyzed in comparison with controls (n = 30) to identify predictors amongst these parameters for disease occurrence and progression. The serum Cu and Zn were established using Flame Atomic Absorption Spectrometry. Serum estimation of Se and Mo was done by graphite furnace atomic absorption spectrometry (GFAAS). Data analysis revealed a marked, progressive and significant increase in Cu levels in precancer (OSMF) and cancer (OSCC) groups as compared to the normal group. The level of Zn in serum was slightly elevated in OSMF and OSCC though not statistically significant. Cu/Zn ratio was slightly but not significantly elevated. Serum levels of Se and Mo were significantly decreased in the precancer and cancer groups as compared to the normals.