Effect of impeller type and mechanical agitation on the mass transfer and power consumption aspects of ASBR operation treating synthetic wastewater

The effect of flow type and rotor speed was investigated in a round-bottom reactor with 5 L useful volume containing 2.0 L of granular biomass. The reactor treated 2.0 L of synthetic wastewater with a concentration of 800 mgCOD/L in 8-h cycles at 30 degrees C. Five impellers, commonly used in biological processes, have been employed to this end, namely: a turbine and a paddle impeller with six-vertical-flat-blades, a turbine and a paddle impeller with six-45 degrees-inclined-flat-blades and a three-blade-helix impeller. Results showed that altering impeller type and rotor speed did not significantly affect system stability and performance. Average organic matter removal efficiency was about 84% for filtered samples, total volatile acids concentration was below 20 mgHAc/L and bicarbonate alkalinity a little less than 400 mgCaCO(3)/L for most of the investigated conditions. However, analysis of the first-order kinetic model constants showed that alteration in rotor speed resulted in an increase in the values of the kinetic constants (for instance, from 0.57 h(-1) at 50 rpm to 0.84 h(-1) at 75 rpm when the paddle impeller with six-45 degrees-inclined-flat-blades was used) and that axial flow in mechanically stirred reactors is preferable over radial-flow when the vertical-flat-blade impeller is compared to the inclined-flat-blade impeller (for instance at 75 rpm, from 0.52 h(-1) with the six-flat-blade-paddle impeller to 0.84 h(-1) with the six-45 degrees-inclined-flat-blade-paddle impeller), demonstrating that there is a rotor speed and an impeller type that maximize solid-liquid mass transfer in the reaction medium. Furthermore, power consumption studies in this reduced reactor volume showed that no high power transfer is required to improve mass transfer (less than 0.6 kW/10(3) m(3)). (C) 2008 Elsevier Ltd. All rights reserved.

Dodigen 213-N as corrosion inhibitor for ASTM 1010 mild steel in 10% HCL

This article describes a study of the behavior of a mixture of amines and amides, commercially known as Dodigen 213-N (D-213 N), as a corrosion inhibitor for ASTM 1010 mild steel in 10% w/w HCl solution. The concentration range used was 1 x 10(-5) M to 8 x 10(-4) M. The weight loss and electrochemical techniques used were corrosion potential measurement, anodic and cathodic polarization curves, and electrochemical impedance spectroscopy (EIS). The solution temperature was 50 +/- A 1 A degrees C and it was naturally aerated. The corrosion potential values shifted to slightly more positive values, thus indicating mixed inhibitor behavior. The anodic and cathodic polarization curves showed that D-213 N is an effective corrosion inhibitor, since both the anodic and the cathodic reactions were polarized in comparison with those obtained without inhibitor. For all concentrations the cathodic polarization curves were more polarized than the anodic ones. The inhibition efficiency was in the range 75-98%, calculated from values of weight loss and corrosion current density, i (corr), obtained by extrapolation of Tafel cathodic linear region.

Phase equilibria for salt-induced lysozyme precipitation: Effect of salt type and temperature

The salt-induced precipitation of lysozyme from aqueous solutions was studied through precipitation assays in which the equilibrium compositions of the coexisting phases were determined. Lysozyme precipitation experiments were carried out at 5, 15 and 25 degrees C and pH 7.0 with ammonium sulfate, sodium sulfate and sodium chloride as precipitating agents. In these experiments a complete separation of the coexisting phases (liquid and solid) could not be achieved. Nevertheless it was possible to determine the composition of the precipitate. The enzymatic activity of lysozyme in the supernatant phase as well as in the precipitate phase was also determined. The activity balance suggests that there is a relationship between the composition of the true precipitate and the total activity recovery. (C) 2009 Elsevier B.V. All rights reserved.

Isolation and analysis of bioactive isoflavonoids and chalcone from a new type of Brazilian propolis

Activity-directed fractionation and purification processes were employed to identify isoflavonoids with antioxidant and antimicrobial activities from Brazilian red propolis. Crude propolis was extracted with ethanol (80%. v/v) and fractioned by liquid-liquid extraction technique using hexane and chloroform. Since chloroform fraction showed strong antioxidant and antimicrobial activities it was purified and isolated using various chromatographic techniques. Comparing our spectral data (UV, NMR, and mass spectrometry) with values found in the literature, we identified two bioactive isoflavonoids (vestitol and neovestitol), together with one chalcone (isoliquiritigenin). Vestitol presented higher antioxidant activity against beta-carotene consumption than neovestitol. The antimicrobial activity of these three compounds against Staphylococcus aureus, Streptococcus mutans, and Actinomyces naeslundii was evaluated and we concluded that isoliquiritigenin was the most active one with lower MIC, ranging from 15.6 to 62.5 mu g/mL. Our results showed that Brazilian red propolis has biologically active isoflavonoids that may be used as a mild antioxidant and antimicrobial for food preservation. (C) 2010 Elsevier B.V. All rights reserved.

Adenanthera pavonina TRYPSIN INHIBITOR RETARD GROWTH OF Anagasta kuehniella (LEPIDOPTERA: PYRALIDAE)

Anagasta kuehniella is a polyphagous pest that feeds on a wide variety of stored products. The possible roles suggested for seed proteinase inhibitors include the function as a part of the plant defensive system against pest via inhibition of their proteolytic enzymes. In this study, a trypsin inhibitor (ApTI) was purified from Adenanthera pavonina seed and was tested for insect growth regulatory effect. The chronic ingestion of ApTI did result in a significant reduction in larval survival and weight. Larval and pupal developmental time of larvae fed on ApTI diet at 1% was significantly longer; the larval period was extended by 5 days and pupal period was 10 days longer, therefore delaying by up to 20 days and resulting in a prolonged period of development from larva to adult. As a result, the ApTI diet emergence rate was only 28% while the emergence rate of control larvae was 80%. The percentage of surviving adults (%S) decreased to 62%. The fourth instar larvae reared on a diet containing 1% ApTI showed a decrease in tryptic activity of gut and that no novel proteolytic form resistant to ApTI was induced. In addition, the tryptic activity in ApTI -fed larvae was sensitive to ApTI. These results suggest that ApTI have a potential antimetabolic effect when ingested by A. kuehniella. (C) 2010 Wiley Periodicals, Inc.

Regulatory effects of an inhibitor from Plathymenia foliolosa seeds on the larval development of Anagasta kuehniella (Lepidoptera)

The Mediterranean flour moth, Anagasta kuehniella, is one of the most important insect pests of grains, reported worldwide, feeding on stored grains and products of rice, rye, corn and wheat. Plants synthesize a variety of molecules, including trypsin inhibitors, to defend themselves against attack by insects. In this study, a trypsin inhibitor (PFTI) was purified from Plathymenia foliolosa (Benth.) seeds and was tested for insect growth regulatory effect. The survival and mass of A. kuehniella larvae feeding on control seeds were about 82.7% and 5 ring, respectively, whereas survival on seeds containing 0.7% PFTI was about 56%, while a 66.1% reduction in the average mass of the larvae was observed. The results from dietary utilization experiments with A. kuehniella larvae showed a reduction in efficiency of conversion of ingested food and digested food, and an increase in approximate digestibility and metabolic cost. The level of trypsin was significantly decreased in larval midgut and increased in the feces of larvae reared on a diet containing 0.7% PFTI. Results indicate that PFTI possesses a toxic effect against A. kuehniella larvae. (C) 2008 Elsevier Inc. All rights reserved.

Purification and Characterization of a Trypsin Inhibitor from Plathymenia foliolosa Seeds

A novel trypsin inhibitor (PFTI) was isolated from Plathymenia foliolosa (Benth.) seeds by gel filtration chromatography on a Sephadex G-100, DEAE-Sepharose, and trypsin-Sepharose columns. By SDS-PAGE, PFTI yielded a single band with a M(r) of 19 kDa. PFTI inhibited bovine trypsin and bovine chymotrypsin with equilibrium dissociation constants (K(i)) of 4 x 10(-8) and 1.4 x 10(-6) M, respectively. PFTI retained more than 50% of activity at up to 50 degrees C for 30 min, but there were 80 and 100% losses of activity at 60 and 70 degrees C, respectively. DTT affected the activity or stability of PFTI. The N-terminal amino acid sequence of PFTI showed a high degree of homology with various members of the Kunitz family of inhibitors. Anagasta kuehniella is found worldwide; this insect attacks stored grains and products of rice, oat, rye, corn, and wheat. The velvet bean caterpillar (Anticarsia gemmatalis) is considered the main defoliator pest of soybean in Brazil. Diatraea saccharalis, the sugar cane borer, is the major pest of sugar cane crops, and its caterpillar-feeding behavior, inside the stems, hampers control. PFTI showed significant inhibitory activity against trypsin-like proteases present in the larval midguts on A. kuehniella and D. saccharalis and could suppress the growth of larvae.

Influence of magnesium status and magnesium intake on the blood glucose control in patients with type 2 diabetes

Background & aims: This study was undertaken to assess magnesium intake and magnesium status in patients with type 2 diabetes, and to identify the parameters that best predict alterations in fasting glucose and plasma magnesium. Methods: A cross-sectional study was carried out in patients with type 2 diabetes (n = 51; 53.6 +/- 10.5 y) selected within the inclusion factors, at the University Hospital Onofre Lopes. Magnesium intake was assessed by three 24-h recalls. Urine, plasma and erythrocytes magnesium, fasting and 2-h postprandial glucose, HbA1, microalbuminuria, proteinuria, and serum and urine creatinine were measured. Results: Mean magnesium intake (9.37 +/- 1.76 mmol/d), urine magnesium (2.80 +/- 1.51 mmol/d), plasma magnesium (0.71 +/- 0.08 mmol/L) and erythrocyte magnesium (1.92 +/- 0.23 mmol/L) levels were low. Seventy-seven percent of participants presented one or more magnesium status parameters below the cut-off points of 3.00 mmol/L for urine, 0.75 mmol/L for plasma and 1.65 mmol/L for erythrocytes. Subjects presented poor blood glucose control with fasting glucose of 8.1 +/- 3.7 mmol/L, 2-h postprandial glucose of 11.1 +/- 5.1 mmol/L, and HbA1 of 11.4 +/- 3.0%. The parameters that influenced fasting glucose were urine, plasma and dietary magnesium, while plasma magnesium was influenced by creatinine clearance. Conclusions: Magnesium status was influenced by kidney depuration and was altered in patients with type 2 diabetes, and magnesium showed to play an important role in blood glucose control. (C) 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

EVALUATION OF RED CURRANTS (RIBES RUBRUM L.), BLACK CURRANTS (RIBES NIGRUM L.), RED AND GREEN GOOSEBERRIES (RIBES UVA-CRISPA) FOR POTENTIAL MANAGEMENT OF TYPE 2 DIABETES AND HYPERTENSION USING IN VITRO MODELS

Red currants (Ribes rubrum L.), black currants (Ribes nigrum L.), red and green gooseberries (Ribes uva-crispa) were evaluated for the total phenolics, antioxidant capacity based on 2, 2-diphenyl-1-picrylhydrazyl radical scavenging assay and functionality such as in vitro inhibition of alpha-amylase, alpha-glucosidase and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension. The total phenolics content ranged from 3.2 (green gooseberries) to 13.5 (black currants) mg/g fruit fresh weight. No correlation was found between total phenolics and antioxidant activity. The major phenolic compounds were quercetin derivatives (black currants and green gooseberries) and chlorogenic acid (red currants and red gooseberries). Red currants had the highest alpha-glucosidase, alpha-amylase and ACE inhibitory activities. Therefore red currants could be good dietary sources with potential antidiabetes and antihypertension functionality to compliment overall dietary management of early stages of type 2 diabetes.

Changes in bone mass, biomechanical properties, and microarchitecture of calcium- and iron-deficient rats fed diets supplemented with inulin-type fructans

Feeding mineral-deficient diets enhances absorptive efficiency as an attempt of the body to compensate for the lack of an essential nutrient. Under certain circumstances, it does not succeed, and nutritional deficiency is produced Our hypothesis was that mulin-type fructans (ITF), which arc known to affect mineral absorption, could increase Ca and Fe bioavailability in Ca- and Fe-deficient rats. Male Wistar rats (n = 48, 4 weeks old) were assigned to I of 8 groups derived from 2 x 2 x 2 factorial design with 2 levels of added Fe (0 and 35 mg/kg), Ca (0 and 5 g/kg), and ITF (0 and 100 g/kg) for 33 days. The Fe status (hemoglobin, serum Fe, total Fe-binding capacity, transferrin saturation, liver minerals) was evaluated. Tibia minerals (Ca, Mg, and Zn), bone strength, and histomorphometry were determined In nondeficient rats, ITF supplementation did not affect Fe status or organ minerals, with the exception of tibia Mg Moreover, ITF improved bone resilience and led to a reduction in eroded surface per body surface and number of osteoclasts per area In Ca-deficient rats, ITF increased liver (Fe and Zn) and tibia (Zn) mineral levels but impaired tibia Mg, yield load, and resilience. In conclusion, ITF worsened the tibia Mg levels and elastic properties when supplemented in Ca-deficient diets In contrast, although bone Ca was not affected in nondeficient rats under the present experimental conditions, bone quality improved, as demonstrated by a moderate reduction in femur osteoclast resorption and significant increases in tibia Mg content and elasticity. (C) 2009 Elsevier Inc. All rights reserved.

Kinetic and thermodynamic investigation on clavulanic acid formation and degradation during glycerol fermentation by Streptomyces DAUFPE 3060

Clavulanic acid (CA) is a potent inhibitor of beta-lactamases, produced by some resistant pathogenic microorganisms, which allows efficient treatment of infectious diseases. The kinetic and thermodynamic parameters of CA production by a new isolate of Streptomyces DAUFPE 3060 and its degradation were evaluated. The effect of temperature on the system was investigated in the range 24-40 degrees C adopting an overall model accounting for (a) the Arrhenius-type formation of CA by fermentation, (b) the hypothetical reversible unfolding of the enzyme limiting the overall metabolism, and (c) the irreversible first-order degradation of CA. The higher rates of CA formation (k(CA) = 0,107 h(-1)) and degradation (k(d) = 0.062 h(-1)) were observed at 32 and 40 degrees C, respectively. The main thermodynamic parameters of the three above hypothesized events were estimated. In particular, the activation parameters of degradation (activation energy = 39.0 kJ/mol; Delta H(d)* = 36.5 kJ/mol; Delta S(d)* = -219.7 J/(mol K); Delta G(d)* = 103.5 kJ/mol) compare reasonably well with those reported in the literature for similar system without taking into account the other two events. (C) 2009 Elsevier Inc. All rights reserved.

Purification of alpha-toxin from Clostridium perfringens type A in PEG-phosphate aqueous two-phase systems: a factorial study

BACKGROUND: Purification of a-toxin produced by Clostridium perfringens type A in aqueous two-phase systems (ATPS) was studied with a full two-level factorial design on two factors (concentrations of 8000 g mol(-1) PEG and phosphate salt at pH 8.0), to estimate the influence of these factors on the purification results. RESULTS: The partition coefficient (K), purification factor (PF) and activity yield (Y) were strongly influenced by the PEG and phosphate concentrations. Raising the levels of the two factors increased these responses. The highest purification factor (5.7) was obtained with PEG and phosphate concentrations of 17.5% and 15%, respectively. CONCLUSION: These results support the proposal that polymer excluded volume and hydrophobic interactions are the factors that drive the alpha-toxin in PEG/phosphate aqueous two-phase systems. (c) 2008 Society of Chemical Industry

Bioequivalence and pharmacokinetics of two zidovudine formulations in healthy Brazilian volunteers: An open-label, randomized, single-dose, two-way crossover study

Background: Zidovudine is a thymidine nucleoside reverse transcriptase inhibitor with activity against HIV type 1. Some (similar to 8) generic formulations of zidovudine are available in Brazil; however, based on a literature search, information concerning their bioavailability and pharmacokinetic properties in the Brazilian population has not been reported. Objective: The aim of this study was to compare the bioavailability and pharmacokinetic properties of 2 capsule formulations of zidovudine 100 mg in healthy Brazilian volunteers. Methods: This open-label, randomized, 2-way crossover study utilized a 1-week washout period between doses. Blood samples were collected for 8 hours after a single dose of zidovudine 100-mg test (Zidovudina, Fundaqdo para o Remedio Popular, Sao Paulo, Brazil) or reference formulation (Retrovir (R), GlaxoSmithKline, Philadelphia, Pennsylvania). Plasma zidovudine concentrations were determined using a validated high-performance liquid chromatography method with ultraviolet detection at 265 nm. C-max, T-max, AUC(0-t), AUC(0-infinity), t(1/2), and the elimination constant (k(e)) were determined using noncompartmental analysis. The formulations were considered bioequivalent if the 90% CIS for C-max, AUC(0-t), and AUC(0-infinity) fell within the interval of 80 % to 125 %, the regulatory definition set by the US Food and Drug Administration (FDA). Results: Twenty-four healthy volunteers (12 males, 12 females; mean age, 27 years; weight, 60 kg; height, 167 cm) were enrolled and completed the study. The 90% CIs of the treatment ratios for the logarithmic-transformed values of C-max, AUC(0-t), and AUC(0-infinity) were 80.0% to 113.6%, 93.9% to 109.7%, and 93.6% to 110.1 %, respectively. The values for the test and reference formulations were within the FDA bioequivalence definition intervals of 80% to 125%. Conclusions: In this small study in healthy subjects, no statistically significant differences in C-max, AUC(0-t), and AUC(0-)infinity were found between the test and reference formulations of zidovudine 100-mg capsules. The 90% CIs for the mean ratio values for the test and reference formulations of AUC(0-t), AUC(0-infinity), and C-max indicated that the reported data were entirely within the bioequivalence acceptance range proposed by the FDA of 80% to 125% (using log-transformed data).

Increase of core temperature induced by corticotropin-releasing factor and urocortin: A comparative study

This study compared the ability of CRF and UCN1 to induce a thermoregulatory response when centrally injected into rats. The effects of antipyretic drugs and CRF receptor antagonists (CRF(1) and CRF(2)) on the temperature (T) changes induced by these peptides were also investigated. Rectal (rT) and tail skin (T(sk)) temperatures were measured with a thermistor probe while body (bT) temperature was measured with a battery-operated biotelemetry transmitter in male Wistar rats (200 g) every 30 min over a period of 6 h, after intracerebroventricular (i.c.v.) injection of 1 nmol of either CRF or UCN1. Rats were pre-treated with indomethacin (2 mg kg(-1), i.p.) or celecoxib (5 mg kg(-1), p.o.), dexamethasone (0.5 mg kg(-1), s.c.), astressin (a CRF(1)/CRF(2) antagonist, 7 nmol, icy.) or antalarmin (a CRF(1) antagonist, 20 mg kg 1, i.p.). The increase in body temperature induced by CRF was accompanied by a reduction in T(sk) while the response induced by UCN1 was accompanied by an elevation in T(sk). Indomethacin or celecoxib did not change the increases in rT caused by either CRF or UCN1. Although dexamethasone attenuated the increase in rectal temperature in response to CRF, dexamethasone did not modify the response induced by UCN1. Astressin blocked the UCN1-induced hyperthermia and reduced CRF-induced fever. Antalarmin did not modify the hyperthermia in response to UCN1, but reduced the fever evoked by CRF. This study demonstrated that CRF by acting on the CRF(1) receptor induces a prostaglandin-independent fever which seems to depend, at least in part, on the synthesis of other mediators while UCN1 acts on the CRF(2) receptor, promoting a hyperthermic response which seems to be independent on synthesis/release of any mediator. (C) 2010 Elsevier B.V. All rights reserved.

Using Computer-aided Drug Design and Medicinal Chemistry Strategies in the Fight Against Diabetes

The aim of this work is to present a simple, practical and efficient protocol for drug design, in particular Diabetes, which includes selection of the illness, good choice of a target as well as a bioactive ligand and then usage of various computer aided drug design and medicinal chemistry tools to design novel potential drug candidates in different diseases. We have selected the validated target dipeptidyl peptidase IV (DPP-IV), whose inhibition contributes to reduce glucose levels in type 2 diabetes patients. The most active inhibitor with complex X-ray structure reported was initially extracted from the BindingDB database. By using molecular modification strategies widely used in medicinal chemistry, besides current state-of-the-art tools in drug design (including flexible docking, virtual screening, molecular interaction fields, molecular dynamics. ADME and toxicity predictions), we have proposed 4 novel potential DPP-IV inhibitors with drug properties for Diabetes control, which have been supported and validated by all the computational tools used herewith.