Effects of feedstock, airflow rate, and recirculation ratio on performance of composting systems with air recirculation

The thermodynamics, kinetics, and energy use of composting systems with air recirculation were determined for feedstocks comprising paper mill sludge and biosolids. Results were developed by simulating the composting system using a two-dimensional finite difference numerical model. Incorporated into the simulation model was independent regulation of temperature and oxygen using a closed loop feedback control system with a two-stage fan setting. Results showed that at low airflows and high recirculation ratios, heat removal by the exhaust gas was insufficient to maintain set point temperatures with the result that process temperatures increased and eventually limited the reaction rate. Types of feedstock, magnitude of airflow and recirculation ratio all affected the energy use of the system. Although recirculation leads to high energy use, it can produce high quality compost by having a temperature gradient of less than 2 degrees C across the bed.     

Sildenafil is a strong activator of mammalian carbonic anhydrase isoforms I–XIV

Sildenafil citrate, a phosphodiesterase-5 (PDE5) inhibitor widely used for the treatment of erectile dysfunction was investigated for its interaction with the zinc-enzyme carbonic anhydrase (CA, EC 4.2.1.1), as it has in its molecule a piperazine moiety also found in some CA activators (CAAs). Sildenafil was a potent, low micromolar activator of several CA isozymes, such as CA I, VA and VI (K_As in the range of 1.08–6.54 μM), and activated slightly less the isoforms CA III, IV and VA (K_As of 13.4–16.8 μM). CA isozymes II, IX, XIII and XIV showed activation constants in the range of 27.5–34.0 μM, whereas the least activated isoforms were CA VII and XII (K_As of 72.9–73.0 μM). Sildenafil citrate was also given orally to Sprague-Dawley rats at 1 mg/kg body weight. Red blood cell CA activity was inhibited in the treated animals at 3–5 h post-administration (in the range of 60–85%), probably due to NO/nitrite formed by PDE5 inhibition or by another, unknown mechanism. Whether CA activation by sildenafil has clinical consequences in humans is beyond the scope of the present work and warrants further studies.     

Determination of Physiological Indices and Some Antioxidant Enzymes of Chard Exposed to Nitric Oxide under Drought Stress

Russian Journal of Plant Physiology - This research was carried out to determine effectiveness of nitric oxide (NO) on some physiological and biochemical reactions, and water use efficiency (WUE)...     

Influence of Cobalt and Zinc Exposure on mRNA Expression Profiles of Metallothionein and Cytocrome P450 in Rainbow Trout

The present research aims to evaluate the effects of cobalt and zinc exposure of rainbow trout (Oncorhynchus mykiss) on metallothioneins and cytocrome P450. Mature rainbow trouts were exposed to 10?mg/L CoCl(2).6H(2)O and 1?mg/L ZnSO(4).7H(2)O. After 6, 12, 24, and 48?h of treatment, expressions of muscle MT-A, MT-B, and CYP P4501A1 mRNAs were measured by means of quantitative real-time polymerase chain reaction. During the exposure experiments, no mortalities occurred. We observed that expression levels of all genes increased with exposure time. Since the organism has not learned how to completely dispose of heavy metals and tends to bioaccumulate them, our results indicate that cobalt and zinc exposure may result in accumulation of the non-eliminated metals which may lead to fish death.     

Characterization and anions inhibition studies of an α-carbonic anhydrase from the teleost fish Dicentrarchus labrax

Carbonic anhydrase (CA; EC 4.2.1.1) was purified from the gill of the teleost fish Dicentrarchus labrax (European seabass). The purification procedure consisted of a single step affinity chromatography on Sepharose 4B-tyrosine-sulfanilamide. The enzyme was purified 84.9-fold with a yield of 58%, and a specific activity of 838.9 U/mg proteins. It has an optimum pH at 8.0; an optimum temperature at 10°C. The kinetic parameters of this enzyme were determined for its esterase activity, with 4-nitrophenyl acetate (NPA) as substrate. The following anions, H?NSO??, I?, SCN?, NO??, NO??, N??, Br?, Cl?, SO?2?, and F? showed inhibitory effects on the enzyme. Sulfamic acid, iodide, and thiocyanate exhibited the strongest inhibitory action, in the micromolar range (K(i)s of 87-187 μM). NO??, NO?? and N?? were moderate inhibitors, whereas other anions showed only weak actions. All tested anions inhibited the enzyme in a competitive manner. Our findings indicate that these anions inhibit the fish enzyme in a similar manner to other α-CAs from mammals investigated earlier, but the susceptibility to various anions differs significantly between the fish and mammalian CAs.     

The effects of Fusilade (Fluazifop-<Emphasis Type="Italic">p</Emphasis>-butyl) on germination,mitotic frequency and α-amylase activity of lentil (<Emphasis Type="Italic">Lens culinaris</Emphasis> Medik.) seeds

In this study, seed germination percentages, effects on phases of mitosis and α-amylase enzyme activity of lentil seeds treated with four different concentrations (0.25, 0.5, 1 and 1.5%) of Fusilade (Fluazifop-p-butyl) were determined. Median EC (effective concentration) values were calculated according to seed germination percentages after treatment for 72 h. Germination percentages of primary lentil roots decreased with increasing Fusilade concentrations. Cytological observations showed that the mitotic frequency in root meristematic cells were decreased parallel to the increase in concentrations and all Fusilade concentrations applied decreased the activity of α-amylase enzyme in lentil seeds. The obtained results indicate that the herbicide Fusilade had the ability to cause reduction in seed germination, mitotic frequency and also α-amylase activity of lentil seeds.     

Mitigation of salinity stress in cucumber seedlings by exogenous hydrogen sulfide

Journal of Plant Research - This research hypothesized that tolerance of cucumber seedlings to salinity stress could be increased by hydrogen sulfide (H2S) treatments. In pot experiments, the...     

Determination of the inhibitory effects of N-methylpyrrole derivatives on glutathione reductase enzyme

Glutathione reductase (GR) is a crucial antioxidant enzyme which is responsible for the maintenance of antioxidant GSH molecule. Antimalarial effects of some chemical molecules are attributed to their inhibition of GR, thus inhibitors of this enzyme are expected to be promising candidates for the treatment of malaria. In this work, GR inhibitory properties of N-Methylpyrrole derivatives are reported. It was found that all compounds have better inhibitory activity than the strong GR inhibitor N,N-bis(2-chloroethyl)-N-nitrosourea, especially three molecules, 8?m, 8 n, and 8 q, were determined to be the most powerful among them. Findings of our study indicates that these Schiff base derivatives are strong GR inhibitors which can be used as leads for designation of novel antimalarial candidates.     

Carbonic anhydrase from Apis mellifera: purification and inhibition by pesticides

Carbonic anhydrase (CA) enzymes have been shown to play an important role in ion transport and in pH regulation in several organisms. Despite this information and the wealth of knowledge regarding the significance of CA enzymes, few studies have been reported about bee CA enzymes and the hazardous effects of chemicals. Using Apis mellifera as a model, this study aimed to determine the risk of pesticides on Apis mellifera Carbonic anhydrase enzyme (Am CA). CA was initially purified from Apis mellifera spermatheca for the first time in the literature. The enzyme was purified with an overall purification of ～35-fold with a molecular weight of ～32?kDa. The enzyme was then exposed to pesticides, including tebuconazole, propoxur, carbaryl, carbofuran, simazine and atrazine. The six pesticides dose-dependently inhibited in vitro AmCA activity at low micromolar concentrations. IC₅₀ values for the pesticides were 0.0030, 0.0321, 0.0031, 0.0087, 0.0273 and 0.0165?μM, respectively. The AmCA inhibition mechanism of these compounds is unknown at this moment.