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1.
Li L  Tang F  O WS 《Theriogenology》2012,77(9):1846-1853
Concentrations of adrenomedullin (ADM) in circulation, the uterus, and corpora lutea (CL) increase during pregnancy. We previously reported a temporal-spatial pattern of ADM level and gene expression of Adm and its receptor components, from early pregnancy through midpregnancy to late pregnancy in rats. Two earlier reports using an in vivo model of ADM antagonism demonstrated the important roles of ADM in the post-implantation period. Treatment with ADM receptor blocker hADM22-52 starting from gestation Day 8 or Day 14 resulted in fetal-placental growth restriction and reduction in litter size. In this study, the endogenous ADM actions were abolished in the preimplantation period by infusing the antagonist for the ADM receptor (hADM22-52) with the osmotic (Alzet) pump from Days 1-4 of pregnancy. We inferred that ADM, acting through the ADM receptor, had critical roles during preimplantation, as brief inhibition of ADM action by hADM22-52 during this period reduced litter size by restricting placental growth and increasing fetal resorption in midpregnancy.  相似文献   

2.
The objective of the study was to examine the application of the Anaerobic Digestion Model No. 1 (ADM1) developed by the IWA task group for mathematical modelling of anaerobic process. Lab-scale temperature-phased anaerobic digestion (TPAD) process were operated continuously, and were fed with co-substrate composed of dog food and flour. The model platform implemented in the simulation was a derivative of the ADM1. Sensitivity analysis showed that km.process (maximum specific uptake rate) and KS.process (half saturation value) had high sensitivities to model components. Important parameters including maximum uptake rate for propionate utilisers (km.pro) and half saturation constant for acetate utilisers (KS.ac) in the thermophilic digester and maximum uptake rate for acetate utilisers (km.ac) in the mesophilic digester were estimated using iterative methods, which optimized the parameters with experimental results. Simulation with estimated parameters showed good agreement with experimental results in the case of methane production, uptake of acetate, soluble chemical oxygen demand (SCOD) and total chemical oxygen demand (TCOD). Under these conditions, the model predicted reasonably well the dynamic behavior of the TPAD process for verifying the model.  相似文献   

3.
The purpose of this study was to develop a dosage form that was easy to administer and provides rapid release of the drug roxithromycin, using modified polysaccharides as rapidly disintegrating excipients. Modified polysaccharides co grinded treated agar (C-TAG) and co grinded treated guar gum (C-TGG) were prepared by subjecting pure polysaccharides namely agar and guar gum respectively to sequential processes of wetting, drying and co grinding with mannitol (1:1). The modified polysaccharides were characterized by Scanning Electron Microscopy and Diffuse Reflectance Spectroscopy and evaluated for particle size distribution, derived properties, swelling index and biodegradability. Optimization studies based on 22 factorial designs, with friability and disintegration time as response parameters were used to formulate orodispersible tablets of roxithromycin and evaluated for wetting time, water absorption ratio and in vitro drug release at salivary pH 6.4 and physiological pH 7.4. Results indicated that lower levels of modified polysaccharides namely C-TAG in F3 and C-TGG in F7 and higher levels of microcrystalline cellulose, exhibited least disintegration times without friability concerns. In vitro release of optimized formulations F3 and F7, both at salivary pH and physiological pH was found to be more than 90% within 30 min as compared to 27.82% at the same time point of conventional formulation. Stability studies carried out as per ICH Q1A guidelines suggested the formulations to be stable for a period of 6 months. Thus the approach of using modified polysaccharides as fast disintegrating excipient can be used to formulate a stable orodispersible formulation.  相似文献   

4.
The main goal of this study was to present a comparison of landfill performance with respect to solids decomposition. Biochemical methane potential (BMP) test was used to determine the initial and the remaining CH4 potentials of solid wastes during 27 months of landfilling operation in two pilot scale landfill reactors. The initial methane potential of solid wastes filled to the reactors was around 0.347 L/CH4/g dry waste, which decreased with operational time of landfill reactors to values of 0.117 and 0.154 L/CH4/g dry waste for leachate recirculated (R1) and non-recirculated (R2) reactors, respectively. Results indicated that the average rate constant increased by 32% with leachate recirculation. Also, the performance of the system was modeled using the BMP data for the samples taken from reactors at varying operational times by MATLAB program. The first-order rate constants for R1 and R2 reactors were 0.01571 and 0.01195 1/d, respectively. The correlation between the model and the experimental parameters was more than 95%, showing the good fit of the model.  相似文献   

5.
The use of photosynthetic microalgae for nutrient removal and biofuel production has been widely discussed. Anaerobic digestion of waste microalgal biomass to produce biogas is a promising technology for bioenergy production. However, the methane yield from this anaerobic process was limited because of the hard cell wall of Chlorella vulgaris. The use of ultrasound has proven to be successful at improving the disintegration and anaerobic biodegradability of Chlorella vulgaris. Ultrasonic pretreatment in the range of 5–200 J ml−1 was applied to waste microalgal biomass, which was then used for batch digestion. Ultrasound techniques were successful and showed higher soluble COD at higher applied energy. During batch digestion, cell disintegration due to ultrasound increased in terms of specific biogas production and the degradation rate. Compared to the untreated sample, the specific biogas production was increased in the ultrasound-treated sample by 90% at an energy dose of 200 J ml−1. For the disintegrated samples, volatile solids reduction was also increased according to the energy input and degradation. These results indicate that the hydrolysis of microalgal cells is the rate-limiting step in the anaerobic digestion of microalgal biomass.  相似文献   

6.
Generally, pellets obtained from extrusion/spheronization, containing microcrystalline cellulose (MCC), do not disintegrate. An attempt has been made to develop melt-in-mouth pellets of taste-masked atomoxetine hydrochloride, using extrusion-spheronization, for pediatric patients. Melt-in-mouth pellets were prepared using extrusion-spheronization method and optimized using 33 FFD. MCC (X1, %), mannitol (X2, %) and Indion 414: Pharmaburst 500 ratio (X3, ratio) were the factors (independent variables) studied, whereas responses studied (dependent variables) were friability (Y1, %), yield (Y2, %) shape (Y3, roundness) in vitro disintegration time (Y4, seconds). The optimized formulation obtained from FFD was characterized for friability, shape and morphology, in vitro disintegration time, porosity, moisture uptake, in vitro release study and in vivo taste and disintegration time in healthy human volunteers. Randomized, two-treatment, two-sequence, two-period, single dose, crossover sensory evaluation study of taste-masked melt-in-mouth pellet was carried out in 10 healthy human subjects. A statistically significant polynomial mathematical relationship was generated between the factors and responses to obtain an optimized formulation. The optimized formulation was characterized (in vitro and in vivo) and exhibited a rapid drug release in vitro attributed to fast disintegration of pellets and high solubility of drug in 0.1 N HCl and buffer (pH 6.8). In vivo, 40% of volunteers ranked taste-masked optimized formulation as slightly bitter while 60% ranked it as no taste. The optimized pellets were conveniently administered in volunteers and exhibited rapid in-vivo disintegration in the oral cavity. Melt-in-mouth pellets can be a used as a platform technology for administering drugs to paediatric patients accurately and conveniently resulting in patient compliance.  相似文献   

7.
The anaerobic biodegradability of meat industry wastes was investigated in mesophilic batch reactors and combined with a mathematical model for describing their biodegradable fractions. The characteristics and methane yield achieved when digesting waste sludge, suggested the use of this as co-substrate for enhancing the biodegradability of the other wastes. The co-digestion experiments showed that it would be feasible to co-digest cow manure or ruminal waste with waste sludge, but biodegradability of pig/cow slurries was not improved, being strongly influenced by the ammonium concentration of co-digestion mixture. By applying the mathematical model, it was observed that when increasing the amount of waste sludge in the co-digestion mixtures, the amount of inert and slowly biodegradable fractions decreased leading to an increase in readily biodegradable fractions, volatile solid removal efficiencies and methane yields. These results suggest that using readily biodegradable wastes as co-substrate, the anaerobic biodegradability of complex organic wastes can be improved.  相似文献   

8.
Poly(vinyl alcohol) (PVA)-based formulations are used for pharmaceutical tablet coating with numerous advantages. Our objective is to study the stability of PVA-based coating films in the presence of acidic additives, alkaline additives, and various common impurities typically found in tablet formulations. Opadry® II 85F was used as the model PVA-based coating formulation. The additives and impurities were incorporated into the polymer suspension prior to film casting. Control and test films were analyzed before and after exposure to 40°C/75% relative humidity. Tests included film disintegration, size-exclusion chromatography, thermal analysis, and microscopy. Under stressed conditions, acidic additives (hydrochloric acid (HCl) and ammonium bisulfate (NH4HSO4)) negatively impacted Opadry® II 85F film disintegration while NaOH, formaldehyde, and peroxide did not. Absence of PVA species from the disintegration media corresponded to an increase in crystallinity of PVA for reacted films containing HCl. Films with NH4HSO4 exhibited slower rate of reactivity and less elevation in melting temperature with no clear change in melting enthalpy. Acidic additives posed greater risk of compromise in disintegration of PVA-based coatings than alkaline or common impurities. The mechanism of acid-induced reactivity due to the presence of acidic salts (HCl vs. NH4HSO4) may be different.  相似文献   

9.
Pancreatic ductal adenocarcinoma is believed to arise from precursor lesions termed pancreatic intraepithelial neoplasia (PanIN). Mouse models have demonstrated that targeted expression of activated K-ras to mature acinar cells in the pancreas induces the spontaneous development of PanIN lesions; implying acinar-to-ductal metaplasia (ADM) is a key event in this process. Recent studies suggest Notch signaling is a key regulator of ADM. To assess if Notch1 is required for K-ras driven ADM we employed both an in vivo mouse model and in vitro explant culture system, in which an oncogenic allele of K-ras is activated and Notch1 is deleted simultaneously in acinar cells. Our results demonstrate that oncogenic K-ras is sufficient to drive ADM both in vitro and in vivo but that loss of Notch1 has a minimal effect on this process. Interestingly, while loss of Notch1 in vivo does not affect the severity of PanIN lesions observed, the overall numbers of lesions were greater in mice with deleted Notch1. This suggests Notch1 deletion renders acinar cells more susceptible to formation of K-ras-induced PanINs.  相似文献   

10.
In this study, all the components of Jatropha curcus and Morus indica were chemically characterized and their biochemical methane potentials (BMP) were determined. From the variables that showed strong influence on the ultimate methane yield (Bo) of J. curcus, a multiple regression Jatropha model was developed. This model comprised of total carbohydrates, protein, lipid, acid-detergent fiber (ADF), cellulose and ash in ADF as independent variables, with r2 value of 0.943. The Jatropha model was validated on 7 samples of M. indica parts and wastes from silkworm rearing trays of this study and 13 samples of heterogeneous organic wastes of earlier studies, to judge the prediction quality. It was found that most of the predicted values differed by less than 15% of their experimental Bo.  相似文献   

11.
Mg2+对阿霉素引起心肌线粒体F1F0变化的保护   总被引:4,自引:0,他引:4  
抗肿瘤药物阿霉素(ADM)对心肌线粒体F1F0-复合体呈现抑制而对F1-ATPase无抑制,这表明ADM可能是通过膜脂起作用的,适当浓度Mg2+能降低ADM对复合体的抑制.经 31P-NMR和标记荧光探针NBD-PE,DPH,MC-540以及内源荧光等的测定,结果表明ADM可能首先通过诱导F1F0膜脂形成非双层脂结构,继而影响了膜脂的堆积程度和流动性,进而引起F1F0-复合体酶蛋白构象的改变,最终导致酶活力的降低.Mg2+则可能由于与ADM竞争与心磷脂的结合,而对ADM引起F1F0的变化产生保护作用.  相似文献   

12.
We followed a long-term (up to 503 days) microbial mineralization of dissolved organic carbon (DOC) from lake water in a bioassay and described the kinetics of biodegradation with a new model based on a reactivity continuum approach. The biodegradability of DOC was expressed as the probability of biodegradation, which was assumed to follow a beta distribution. We compared the performance of our beta model to five earlier models: the simplest first order kinetic model, two G models, the power model and the gamma model. The simplest first order kinetic model described the decreasing microbial mineralization of DOC poorly (r 2 = 0.73), but the other models explained the observed kinetics of biodegradation well (r 2 > 0.95). When we assessed the extrapolation power of models beyond the length of the bioassay by reducing the amount of data, the predictive power of the G models was poor. Instead, the beta model predicted the biodegradation kinetics consistently and correctly based on even only three observations in time. The beta model provided also long-term predictions (up to 5,000 years) along the observed long-term mineralization trajectory of organic carbon in sediments. Additionally, the beta model formulated the biodegradability continuum of DOC, which was skewed towards low biodegradability. During the bioassay, the skew towards low biodegradability increased as the most biodegradable parts of DOC were consumed. The beta model describes the biodegradability continuum quantitatively and can predict biodegradation in a realistic manner, thus, improving our understanding about the biodegradability and the role of natural organic matter in the environment.  相似文献   

13.
ObjectiveTo compare stimulus–response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles.MethodsStimulus–response curves of MEPs and SPs were obtained from the biceps brachii (BB) and abductor digiti minimi (ADM) muscles in 15 healthy participants. A nonlinear mixed model was used to fit the stimulus–response curves to a sigmoid Boltzmann function.ResultsSmall residuals of the function were found for MEPs and SPs in both muscles. Higher maximal MEP amplitudes were found for the BB compared to the ADM (p < 0.01). The active motor threshold to obtain a SP was less for the ADM compared to the BB (p < 0.01). The slope parameter of the function of the SP duration was steeper and more variable in the ADM than in the BB (p < 0.01). For the MEP amplitude no difference in active motor threshold and slope of the function was found between both muscles.ConclusionsExcitatory (MEP) and inhibitory (SP) effects of TMS differ between proximal arm and distal hand muscles in healthy participants. The adequate fit of our model suggests that this model can be used to study between and within subject changes in future studies.  相似文献   

14.
《Biomass》1990,21(1):43-54
The effect on anaerobic digestion of reducing the lignin content of vine shoots to 1% (w/w), by treatment with sodium chlorite in an acid medium at 80°C, is reported. The yields of methane obtained were 240 ml of CH4 g−1 of VS (volatile solids) fed for untreated vine shoots, and 370 ml of CH4 g−1 of VS fed for treated vine shoots. A mathematical model was used to calculate the kinetic parameters H and μ, and the increased biodegradability of the substrate in which lignin had been removed was confirmed. A study of the mass balances of the process under optimum conditions (temperature = 35°C; loading rate of 1 g litre−1 digester day−1) enabled the percentage of degraded cellulose to be calculated (35·5% for untreated vine shoots, 81·5% for the treated vine shoots), as were the volumes of biogas and methane produced per gram of VS introduced (VS1) and degraded. The blocking effect of lignin on the methanization process was confirmed.  相似文献   

15.
Biosurfactant production through a fermentation process involving the biodegradation of soybean oil refining wastes was studied. Pseudomonas aeruginosa MR01 was able to produce extracellular biosurfactant when it was cultured in three soybean oil refinement wastes; acid oil, deodorizer distillate and soapstock, at different carbon to nitrogen ratios. Subsequent fermentation kinetics in the three types of waste culture were also investigated and compared with kinetic behavior in soybean oil medium. Biodegradation of wastes, biosurfactant production, biomass growth, nitrate consumption and the number of colony forming units were detected in four proposed media, at specified time intervals. Unexpectedly, wastes could stimulate the biodegradation activity of MR01 bacterial cells and thus biosurfactant synthesis beyond that of the refined soybean oil. This is evident from higher yields of biodegradation and production, as revealed in the waste cultures (Ydeg|(Soybean oil) = 53.9 % < Ydeg|(wastes) and YP/S|(wastes) > YP/S|(Soybean oil) = 0.31 g g?1, respectively). Although production yields were approximately the same in the three waste cultures (YP/S|(wastes) ? 0.5 g g?1), microbial activity resulted in higher yields of biodegradation (96.5 ± 1.13 %), maximum specific growth rate (μ max  = 0.26 ± 0.02 h?1), and biosurfactant purity (89.6 %) with a productivity of 14.55 ± 1.10 g l?1, during the bioconversion of soapstock into biosurfactant. Consequently, applying soybean oil soapstock as a substrate for the production of biosurfactant with commercial value has the potential to provide a combination of economical production with environmental protection through the biosynthesis of an environmentally friendly (green) compound and reduction of waste load entering the environment. Moreover, this work inferred spectrophotometry as an easy method to detect rhamnolipids in the biosurfactant products.  相似文献   

16.
Salt marshes near urban, industrial and mining areas are often affected both by heavy metals and by eutrophic water. The aim of this study was to assess and evaluate the main processes involved in the decrease of nitrate concentration in pore water of mine wastes flooded with eutrophic water, considering the presence or absence of plant rhizhosphere. Basic (pH ∼ 7.8) carbonated loam mine wastes and free-carbonated acidic (pH ∼ 6.2) sandy-loam mine wastes were collected from polluted coastal salt marshes of SE Spain which regularly receive nutrient-enriched water. The wastes were put in pots and flooded for 15 weeks with eutrophic water (dissolved organic carbon ∼26 mg L−1, PO43− ∼23 mg L−1, NO3 ∼180 mg L−1). Three treatments were assayed for each type of waste: pots with Sarcocornia fruticosa, pots with Phragmites australis and unvegetated pots. Soluble organic carbon, nitrate, soluble Cd, Pb and Zn, pH and Eh were monitored. But the 2nd day of flooding, nitrate concentrations had decreased between 70% and 90% (equivalent to 1.01-1.12 g N-NO3 m−2 day−1) with respect to the content in the water used for flooding, except in unvegetated pots with acidic wastes. Denitrification was the main mechanism associated with the removal of nitrate. The role of vegetation in improving the rhizospheric environment was relevant in the acidic wastes because higher sand content, lower pH and higher soluble metal concentrations might strongly hinder microbial activity Hence, revegetation of salt marshes polluted by acidic sandy mining wastes might improve the capacity of this type of environment to act as a green filter against excessive nitrate contents flowing through them.  相似文献   

17.
《Endocrine practice》2016,22(12):1393-1400
Objective: Hypoglycemia remains one of the main challenges of insulin therapy. To reduce insulin-related hypoglycemia at our institution, we restricted inpatient ordering of high glargine doses (≥0.5 U/kg/day) to endocrine staff in May 2013. This retrospective cohort study assesses its effect on hypoglycemia and glycemic control within 48 hours of admission (ADM).Methods: We identified 692 adult patients hospitalized at Boston Medical Center who received glargine upon ADM from November 1, 2012 through April 30, 2013 as the pre-intervention group, and 651 adult patients admitted between November 1, 2013 and April 30, 2014 as the postintervention group. Demographics, medical history, home insulin regimen, concurrent oral diabetes medications or glucocorticoid administration, ADM serum creatinine, all blood glucose levels (BG) ≤48 hours of ADM, and hemoglobin A1c values ≤3 months were assessed. Hypoglycemia was defined as BG ≤70 mg/dL, and hyperglycemia as BG ≥200 mg/dL. Multivariable regression models assessed potential associations between covariates and incidence of hypoglycemia and average BG ≤48 hours of ADM.Results: Demographics were similar between groups. Significantly less patients received high-dose glargine in the post-intervention group (5.2% vs. 0.3%, P<.001). Incidences of hypoglycemia were significantly lower in the postintervention group (20.9% vs. 17.8%, P<.001 per ADM; 3.4% vs. 2.3%, P = .001 per BG measurements [BGM]). Mean BG levels ≤48 hours of ADM and incidence of hyperglycemia were not significantly different. The adjusted incident rate ratio of hypoglycemia was 0.63 per ADM and 0.74 per BGM in the postintervention group compared to the pre-intervention group (P = .001 and P = .063, respectively).Conclusion: We found that implementation of a restriction on high doses of glargine resulted in lower rates of hypoglycemia without worsening glycemic control.Abbreviations:ADM = admissionBG = blood glucoseBGM = blood glucose measurementsBMC = Boston Medical CenterBMI = body mass indexEMR = electronic medical recordHgbA1c = hemoglobin A1cIRR = incidence rate ratioNPH = neutral protamine HagedornTDD = total daily doseT2D = type 2 diabetes  相似文献   

18.
To clarify the mechanism of the cardiotoxic action of adriamycin (ADM), the participation of free radicals from ADM in cardiotoxicity was investigated through the protective action of glutathione (GSH) or by using electron spin resonance (ESR). Oxidation of ADM by horseradish peroxidase and H2O2 (HRP-H2O2) was blocked by GSH concentration dependently. Inactivation of creatine kinase (CK) induced during interaction of ADM with HRP-H2O2 was also protected by GSH. Other anthracycline antitumor drugs that have a p-hydroquinone structure in the B ring also inactivated CK, and GSH inhibited the inactivation of CK. These results suggest that ADM was activated through oxidation of the p-hydroquinone in the B ring by HRP-H2O2. Although ESR signals of the oxidative ADM B ring semiquinone were not detected, glutathionyl radicals were formed during the interaction of ADM with HRP-H2O2 in the presence of GSH. ADM may be oxidized to the ADM B ring semiquinone and then reacts with the SH group. However, ESR signals of ADM C ring semiquinone, which was reductively formed by xanthine oxidase (XO) and hypoxanthine (HX) under anaerobic conditions, were not diminished by GSH, but they completely disappeared with ferric ion. These results indicate that oxidative ADM B ring semiquinones oxidized the SH group in CK, but reductive ADM C ring semiquinone radicals may participate in the oxidation of lipids or DNA and not of the SH group.  相似文献   

19.
Modeling anaerobic digestion of microalgae using ADM1   总被引:1,自引:0,他引:1  
The coupling between a microalgal pond and an anaerobic digester is a promising alternative for sustainable energy production by transforming carbon dioxide into methane using solar energy. In this paper, we demonstrate the ability of the original ADM1 model and a modified version (based on Contois kinetics for the hydrolysis steps) to represent microalgae anaerobic digestion. Simulations were compared to experimental data of an anaerobic digester fed with Chlorella vulgaris. The modified ADM1 fits adequately the data for the considered 140 day experiment encompassing a variety of influent load and flow rates. It turns out to be a reliable predictive tool for optimising the coupling of microalgae with anaerobic digestion processes.  相似文献   

20.
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