Effects on starch and amylolytic enzymes during Lepidium meyenii Walpers root storage

The high water content in maca (Lepidium meyenii W.) roots combined with the damage produced during or after harvest makes them vulnerable to attack by enzymes and microorganisms. Although starch degradation has been extensively studied, in maca roots there is a paucity of research regarding the starch reserves. In this paper, parameters of starch degradation are shown to be related to the action of amylolytic enzymes during storage at room temperature. Over the course of three weeks, the starch and protein content, soluble sugar, total amylolytic activity, and alpha- and beta-amylase activity were measured. In addition, the integrity of starch granules was observed by scanning electron microscopy. Despite the evidence of dehydration, there were no significant differences (p <= 0.5) in the total starch content or in the activities of alpha- and beta-amylase. After the third week the roots remained suitable for consumption. The results indicate a postharvest latency that can lead to sprout or to senescence, depending on the environmental conditions. (C) 2012 Elsevier Ltd. All rights reserved.

Surface Segregation in Chromium-Doped Nanocrystalline Tin Dioxide Pigments

Surface properties play an important role in understanding and controlling nanocrystalline materials. The accumulation of dopants on the surface, caused by surface segregation, can therefore significantly affect nanomaterials properties at low doping levels, offering a way to intentionally control nanoparticles features. In this work, we studied the distribution of chromium ions in SnO2 nanoparticles prepared by a liquid precursor route at moderate temperatures (500 degrees C). The powders were characterized by infrared spectroscopy, X-ray diffraction, (scanning) transmission electron microscopy, Electron Energy Loss Spectroscopy, and Mossbauer spectroscopy. We showed that this synthesis method induces a limited solid solution of chromium into SnO2 and a segregation of chromium to the surface. The s-electron density and symmetry of Sn located on the surface were significantly affected by the doping, while Sn located in the bulk remained unchanged. Chromium ions located on the surface and in the bulk showed distinct oxidation states, giving rise to the intense violet color of the nanoparticles suitable for pigment application.

Validation of reference genes for RT-qPCR normalization in common bean during biotic and abiotic stresses

Selection of reference genes is an essential consideration to increase the precision and quality of relative expression analysis by the quantitative RT-PCR method. The stability of eight expressed sequence tags was evaluated to define potential reference genes to study the differential expression of common bean target genes under biotic (incompatible interaction between common bean and fungus Colletotrichum lindemuthianum) and abiotic (drought; salinity; cold temperature) stresses. The efficiency of amplification curves and quantification cycle (C (q)) were determined using LinRegPCR software. The stability of the candidate reference genes was obtained using geNorm and NormFinder software, whereas the normalization of differential expression of target genes [beta-1,3-glucanase 1 (BG1) gene for biotic stress and dehydration responsive element binding (DREB) gene for abiotic stress] was defined by REST software. High stability was obtained for insulin degrading enzyme (IDE), actin-11 (Act11), unknown 1 (Ukn1) and unknown 2 (Ukn2) genes during biotic stress, and for SKP1/ASK-interacting protein 16 (Skip16), Act11, Tubulin beta-8 (beta-Tub8) and Unk1 genes under abiotic stresses. However, IDE and Act11 were indicated as the best combination of reference genes for biotic stress analysis, whereas the Skip16 and Act11 genes were the best combination to study abiotic stress. These genes should be useful in the normalization of gene expression by RT-PCR analysis in common bean, the most important edible legume.

Hofmeister effects on the colloidal stability of poly(ethylene glycol)-decorated nanoparticles

The colloidal stability of poly(ethylene glycol)-decorated poly(methyl methacrylate), PMMA/Tween-20, particles was investigated by means of phase separation measurements, in the presence of sodium fluoride (NaF), sodium chloride, sodium bromide, sodium nitrate, or sodium thiocyanate (NaSCN) at 1.0 mol L-1. Following Hofmeister's series, the dispersions of PMMA/Tween-20 destabilized faster in the presence of NaF than with NaSCN. After the phase separation, the systems were homogenized and except for the dispersions in NaF, re-dispersed particles took longer to destabilize, indicating that anions adsorbed on the particles, creating a new surface. Except for F- ions, the adsorption of anions on the polar outmost shell was evidenced by means of tensiometry and small-angle X-ray scattering measurements. Fluoride ions induced the dehydration of the polar shell, without affecting the polar shell electron density, and the formation of very large aggregates. A model was proposed to explain the colloidal behavior in the presence of Hofmeister ions.

Alternative management of diabetic ketoacidosis in a Brazilian pediatric emergency department

DKA is a severe metabolic derangement characterized by dehydration, loss of electrolytes, hyperglycemia, hyperketonemia, acidosis and progressive loss of consciousness that results from severe insulin deficiency combined with the effects of increased levels of counterregulatory hormones (catecholamines, glucagon, cortisol, growth hormone). The biochemical criteria for diagnosis are: blood glucose > 200 mg/dl, venous pH <7.3 or bicarbonate <15 mEq/L, ketonemia >3 mmol/L and presence of ketonuria. A patient with DKA must be managed in an emergency ward by an experienced staff or in an intensive care unit (ICU), in order to provide an intensive monitoring of the vital and neurological signs, and of the patient's clinical and biochemical response to treatment. DKA treatment guidelines include: restoration of circulating volume and electrolyte replacement; correction of insulin deficiency aiming at the resolution of metabolic acidosis and ketosis; reduction of risk of cerebral edema; avoidance of other complications of therapy (hypoglycemia, hypokalemia, hyperkalemia, hyperchloremic acidosis); identification and treatment of precipitating events. In Brazil, there are few pediatric ICU beds in public hospitals, so an alternative protocol was designed to abbreviate the time on intravenous infusion lines in order to facilitate DKA management in general emergency wards. The main differences between this protocol and the international guidelines are: intravenous fluid will be stopped when oral fluids are well tolerated and total deficit will be replaced orally; if potassium analysis still indicate need for replacement, it will be given orally; subcutaneous rapid-acting insulin analog is administered at 0.15 U/kg dose every 2-3 hours until resolution of metabolic acidosis; approximately 12 hours after treatment initiation, intermediate-acting (NPH) insulin is initiated at the dose of 0.6-1 U/kg/day, and it will be lowered to 0.4-0.7 U/kg/day at discharge from hospital.

Effects of intravenous furosemide on mucociliary transport and rheological properties of patients under mechanical ventilation

The use of intravenous (IV) furosemide is common practice in patients under mechanical ventilation (MV), but its effects on respiratory mucus are largely unknown. Furosemide can affect respiratory mucus either directly through inhibition of the NaK(Cl)2 co-transporter on the basolateral surface of airway epithelium or indirectly through increased diuresis and dehydration. We investigated the physical properties and transportability of respiratory mucus obtained from 26 patients under MV distributed in two groups, furosemide (n = 12) and control (n = 14). Mucus collection was done at 0, 1, 2, 3 and 4 hours. The rheological properties of mucus were studied with a microrheometer, and in vitro mucociliary transport (MCT) (frog palate), contact angle (CA) and cough clearance (CC) (simulated cough machine) were measured. After the administration of furosemide, MCT decreased by 17 ± 19%, 24 ± 11%, 18 ± 16% and 18 ± 13% at 1, 2, 3 and 4 hours respectively, P < 0.001 compared with control. In contrast, no significant changes were observed in the control group. The remaining parameters did not change significantly in either group. Our results support the hypothesis that IV furosemide might acutely impair MCT in patients under MV.

Isothermal seed germination of Adenanthera pavonina

This work reports aspects of seed germination at different temperatures of Adenanthera pavonina L., a woody Southeast Asian Leguminosae. Germination was studied by measuring the final percentages, the rate, the rate variance and the synchronisation of the individual seeds calculated by the minimal informational entropy of frequencies distribution of seed germination. Overlapping the germinability range with the range for the highest values of germination rates and the minimal informational entropy of frequencies distribution of seed germination, we found that the best temperature for the germination of A. pavonina seeds is 35 ºC. The slope µ of the Arrhenius plot of the germination rates is positive for T < 35 ºC and negative for T > 35 ºC. The activation enthalpies, estimated from closely-spaced points, shows that |ΔH-| < 12 Cal mol-1 occur for temperatures in the range between 25 ºC and 40 ºC. The ecological implication of these results are that this species may germinate very fast in tropical areas during the summer season. This may be an advantage to the establishment of this species under the climatic conditions in those areas.

Análise da suplementação de carboidratos e solução isotônica sobre parâmetros hematológicos e bioquímicos de jogadores profissionais de futebol em condições reais de treinamento

Avaliou-se o efeito de uma suplementação com carboidratos e bebidas esportivas sobre parâmetros laboratoriais em atletas de futebol de campo, em uma situação real de treinamento. Foram coletados 10 ml de sangue venoso e 50 ml de urina em repouso e 15 minutos após treinamento. Os resultados mostram que o exercício intenso causou um variável grau de estase urinária, bem como provocou alterações hidroeletrolíticas caracterizadas por uma diminuição na concentração sérica de sódio, potássio, magnésio, fósforo e glicose (p<0,05), que não foi modificada por nenhum tipo de protocolo de suplementação nas condições propostas no presente estudo. A suplementação eletrolítica proposta mostrou-se limitada para evitar variações eletrolíticas e que a reposição deve ser avaliada à luz de um contexto ambiental e de treinamento.

Cirrus clouds observation in Santa Maria, Rio Grande do Sul during the experiment Chuva - Sul.

Cirrus clouds are an interesting point in the research of the atmosphere due their behavior and the effect on the earth radiation budget. They can affect the atmospheric radiation budget by reflecting the incoming solar radiation and absorbing the outgoing terrestrial radiation. Also, this cloud type is involved in the dehydration of the upper troposphere and lower stratosphere. So, it is interesting to increment the measurements of this type of clouds from the ground. During November and December 2012, through the CHUVA-SUL campaign, measurements with lidar in Santa Maria, Rio Grande do Sul were conducted. The system installed in Santa Maria site (29.8 °S; 53.7 °W, 100 m asl) was a single elastic-backscatter lidar using the wavelength of 532 nm. Some days with cirrus clouds lidar measurements were detected. Four days with presence of cirrus cloud are showed in the present study. These days, 7, 8, 19 and 28 November 2012, was selected due the persistence of cirrus clouds over many hours. The raw retrieval lidar signals and inverted backscatter coefficient profiles were analyzed for the selected days. Base and top height was obtained by analysis of raw signal and backscatter coefficient. Extinction coefficient profiles were obtained by the assumption of the lidar ratio. Cirrus cloud optical depth (COD) values were calculated, from the integration of the extinction coefficient between the base and top altitudes of the cirrus clouds.

Oligonucleotide Adsorption Affects Phase Transition but Not Interdigitation of diC14-Amidine Bilayers

Oligonucleotides have been extensively used in basic research of gene expression and function, vaccine design, and allergy and cancer therapy. Several oligonucleotide-based formulations have reached the clinical trial phase and one is already on the market. All these applications, however, are dependent on suitable carriers that protect oligonucleotides against degradation and improve their capture by target cells. The cationic lipid diC14-amidine efficiently delivers nucleic acids to mammalian cells. It was recently shown that diC14-amidine bilayers present an interdigitated phase which strongly correlates with a potent fusogenic activity at low temperatures. Interdigitated phases correspond to very ordered gel phases where the two bilayer leaflets are merged; they usually result from perturbations at the interfacial region such as modifications of the polar headgroup area or dehydration of the bilayer. Interdigitation has been described for asymmetric lipids or mixed-chain lipids of different chain lengths and for lipids with large effective headgroup sizes. It has also been described for symmetric lipids under pressure modifications or in the presence of alcohol, glycerol, acetonitrile, polymyxin B, or ions like thiocyanate. Surprisingly, the role of polyelectrolytes on membrane interdigitation has been only poorly investigated. In the present work, we use dynamic light scattering (DLS), differential scanning calorimetry (DSC), and electron spin resonance (ESR) to explore the effect of a small single-stranded oligonucleotide (ODN) polyelectrolyte on the structure and colloid stability of interdigitated diC14-amidine membranes.