Cholinergic alterations by exposure to pesticides used in control vector: Guppies fish (Poecilia reticulta) as biological model.

Spinosad and temephos are two of the most used pesticides in Mexico for the control of vector causing disease such as dengue, chikungunya and Zika. The aim of this study was to compare the neurotoxic effects of these two pesticides using guppy fish (Poecilia reticulata) as a model organism. Guppies were exposed for 7 and 21 days to technical grade temephos and spinosad at 1.0 and 0.07 g/L, respectively, (10 and 0.5 mg/L of active substance; concentrations recommended by the Ministery of Health of the State (Secretaría de Salud de Nayarit (SSN) Mexico)). Subsequently, acetylcholinesterase activity (AChE) and acetylcholine concentrations (ACh) in muscle tissue were determined. Temephos exposure decreased AChE activity and increased ACh concentration, whereas exposure to spinosad only increased ACh concentration. Though cholinergic alterations were more severe in fish exposed to temephos, both pesticides were equally lethal during the first seven days after exposure. Nonetheless, temephos was more lethal after 21 days.

Developing strategies to reduce spray drift in pneumatic spraying in vineyards: Assessment of the parameters affecting droplet size in pneumatic spraying.

Pneumatic sprayers are widely used in vineyards due to their very fine droplet size, which makes the drift risk to become an important problem to be considered. The aim of this study was to assess the effect of the spout diameter at the release point on the spray droplet size and uniformity achieved for different liquid flow rates (LFR) and air flow rates (AFR). A test bench was developed to simulate a real pneumatic sprayer under laboratory conditions, and it was empirically adjusted to match the air pressure conditions as closely as possible to real working conditions. Two positions of insertion of the liquid hose, the conventional position (CP) and an alternative position (AP), were tested for three LFRs, 1.00, 1.64, and 2.67Lmin-1, and four AFRs, 0.280, 0.312, 0.345, and 0.376m3s-1. The air speed decrease between the two insertion points of the liquid hose was measured. A Malvern SprayTec® instrument was used to measure the droplet size, and the D50, D10, and D90 parameter values were obtained. The relative SPAN factor (RSF) was also calculated. A model to predict variations in D50 was fitted using the aforementioned parameters. The results show that variations in the diameter of the spout significantly change the droplet size, producing a mean increase of 59.45% in D50 and similar increases in D10 and D90. The model developed to predict variations in D50 has a very high degree of accuracy (R2=0.945). The relative decrease in the air speed along the spout did not present significant differences for the different airflow rates tested. The results of the study show that the droplet size produced in pneumatic spraying can be modified easily by varying the air spout dimensions. This should be taken into account by manufacturers from a design point of view.

Study of the physicochemical effects on the separation of the non-metallic fraction from printed circuit boards by inverse flotation.

Recycling printed circuit boards using green technology is increasingly important due to the metals these contain and the environmental care that must be taken when separating the different materials. Inverse flotation is a process that can be considered a Green Technology, which separates metallic from non-metallic fractions. The degree of separation depends on how much material is adhered to air bubbles. The contact angle measurement allows to determine, in an easy way, whether the flotation process will occur or not and thus establish a material as hydrophobic or not. With the material directly obtained from the milling process, it was found that the contact angle of the non-metallic fraction-liquid-air system increases as temperature increases. In the same way, the increments in concentration of frother in the liquid increase the contact angle of the non-metallic fraction-liquid-air system. 10ppm of Methyl Isobutyl Carbinol provides the highest contact angle as well as the highest material charging in the bubble.

An instrument to measure mechanical up-conversion phenomena in metals in the elastic regime.

Crystalline materials, such as metals, are known to exhibit deviation from a simple linear relation between strain and stress when the latter exceeds the yield stress. In addition, it has been shown that metals respond to varying external stress in a discontinuous way in this regime, exhibiting discrete releases of energy. This crackling noise has been extensively studied both experimentally and theoretically when the metals are operating in the plastic regime. In our study, we focus on the behavior of metals in the elastic regime, where the stresses are well below the yield stress. We describe an instrument that aims to characterize non-linear mechanical noise in metals when stressed in the elastic regime. In macroscopic systems, this phenomenon is expected to manifest as a non-stationary noise modulated by external disturbances applied to the material, a form of mechanical up-conversion of noise. The main motivation for this work is for the case of maraging steel components (cantilevers and wires) in the suspension systems of terrestrial gravitational wave detectors. Such instruments are planned to reach very ambitious displacement sensitivities, and therefore mechanical noise in the cantilevers could prove to be a limiting factor for the detectors' final sensitivities, mainly due to non-linear up-conversion of low frequency residual seismic motion to the frequencies of interest for the gravitational wave observations. We describe here the experimental setup, with a target sensitivity of 10(-15) m/Hz in the frequency range of 10-1000 Hz, a simple phenomenological model of the non-linear mechanical noise, and the analysis method that is inspired by this model.

Separation of the metallic and non-metallic fraction from printed circuit boards employing green technology.

The generation of electrical and electronic waste is increasing day by day; recycling is attractive because of the metallic fraction containing these. Nevertheless, conventional techniques are highly polluting. The comminution of the printed circuit boards followed by an inverse flotation process is a clean technique that allows one to separate the metallic fraction from the non-metallic fraction. It was found that particle size and superficial air velocity are the main variables in the separation of the different fractions. In this way an efficient separation is achieved by avoiding the environmental contamination coupled with the possible utilization of the different fractions obtained.

Increased resolution in neutral atom microscopy.

The neutral atom microscope uses a beam of thermal noncharged atoms or molecules to probe an atomic surface with very low interaction energies (<70 meV). Continued optimization of the 'pinhole' neutral atom microscope has improved resolution to 0.35 µm. Recent images are presented demonstrating resolution and the contrast mechanisms identified so far. The future potential for sub-100 nm resolution is discussed.

Soil management systems and short term CO2 emissions in a clayey soil in southern Spain.

The soil in general and that destined for agricultural use, more specifically, can act as a source or sink of carbon, hence its direct involvement in strategies for mitigating climate change. A large proportion of this mitigation potential is produced by the sequestration of carbon by soils and, to a lesser extent, by a reduction in emissions from the soil. The most effective practices for increasing the organic carbon in the soils are generally those linked to conservation agriculture, which includes practices of no tillage or minimum tillage and the use of cover crops. During the farming seasons of 2006/07, 2007/08, 2008/09 and 2009/10, a trial was conducted in which the carbon dioxide emissions in soil with a high percentage of clay in the Vega de Carmona (Seville) were estimated, and it was determined how climate conditions and the adoption of conservation agriculture practices vs. the use of traditional tillage influenced the flux of gas into the atmosphere.

Fabrication of a versatile substrate for finding samples on the nanometer scale.

With increasing interest in nanometer scale studies, a common research issue is the need to use different analytical systems with a universal substrate to relocate objects on the nanometer scale. Our paper addresses this need. Using the delicate milling capability of a focused ion beam (FIB) system, a region of interest (ROI) on a sample is labelled via a milled reference grid. FIB technology allows for milling and deposition of material at the sub 20-nm level, in a similar user environment as a standard scanning electron microscope (SEM). Presently commercially available transmission electron microscope (TEM) grids have spacings on the order 100 mum on average; this technique can extend this dimension down to the submicrometre level. With a grid on the order of a few micrometres optical, FIBs, TEMs, scanning electron microscopes (SEMs), and atomic force microscopes (AFM) are able to image the ROI, without special chemical processes or conductive coatings required. To demonstrate, Au nanoparticles of approximately 25 nm in size were placed on a commercial Formvar- and carbon-coated TEM grid and later milled with a grid pattern. Demonstration of this technique is also extended to bulk glass substrates for the purpose of sample location. This process is explained and demonstrated using all of the aforementioned analytical techniques.

Acute myocardial infarction: a rare presentation of pancreatic carcinoma.

Secondary neoplastic involvement of the heart is common but usually asymptomatic. Malignancy rarely presents as acute pericarditis, cardiac tamponade, and myocardial infarction in the same patient. We report a patient with unsuspected metastatic pancreatic adenocarcinoma who presented with acute pericarditis and cardiac tamponade and subsequently developed a myocardial infarction due to coronary artery occlusion secondary to a metastatic deposit around the left anterior descending artery.

Changes in Vitellogenin expression during captivity-induced stress in a tropical anole.

Tropical anoline lizards have been shown to undergo massive reproductive retrogression when held in captivity. The present study focused on the effects generated by captivity-induced stress on the hepatic expression of vitellogenin (Vtg), the precursor of the major egg yolk proteins, in Anolis pulchellus. Several hepatic dysfunctions accompanying the regression of the reproductive organs were detected when mature highly vitellogenic females were kept in captivity for long periods. These included decreased synthesis of Vtg to undetectable levels after 4 days of captivity concomitant with a large reduction in the levels of its cognate mRNA. In addition, a drastic reduction in Vtg plasma levels preceding the conspicuous cessation of follicular growth was observed. Results suggest the activation of a specific mechanism for rapid clearance of vitellogenic and other female-specific proteins from plasma. The effects of captivity, both in the liver and in the reproductive tract, were alleviated or even reversed by treatment with 17 Beta-estradiol. Hepatic protein synthesis increased threefold when animals were maintained under estrogen therapy during the captivity period. Also, the levels of Vtg mRNA and Vtg protein synthesis and plasma levels were similar or even higher to the observed in control vitellogenic females. Animals treated with 17 beta-estradiol after long-term captivity recovered the normal vitellogenic levels after 72 to 96 hr. Therefore, our results im this tropical anole strongly suggest that the stress effects upon reproductive behavior previously reported in anoline lizards results from suppression of the estrogen stimulus for the hepatic vitellogenic response.

[Acute trichinosis. Epidemics of 166 cases in Delicias City, Chih. Diagnosis with tissue compression and staining]. / Triquinosis aguda. Epidemia de 166 casos en Ciudad Delicias, Chih. Diagnóstico por compresión tisular y tinción.

The purposes of this report are: a) To show outstanding clinicopathological characteristics from the largest outbreak of trichinosis in México. b) To describe a modification to the traditional trichinoscopy through the use of compressed muscle stained with ordinary dyes an immediate observation; we have called the procedure tissular compression and dyeing technique (TCDT). The outbreak occurred in Delicias, Chihuahua, and affected 166 inhabitants who ate a not well cooked pork sausage. All patients showed malaise, 85.5 percent myalgias, and 72.7 percent facial edema; leucocytosis was seen in 75 percent of the patients, 60 percent with eosinophilia. Electromyography was performed in 21 patients in the acute phase of the illness and it was found abnormal in 85.7 percent. Only one patient died (0.6%). From 59 patients who were considered very ill, muscle biopsies were taken, and the conventional histopathological study showed larvae in 88.1 percent. TCDT demonstrated worms in 90.3 percent out of 47 biopsies; larvae were seen free and into muscle fibers with or without capsule cells. In conclusion TCDT is a simple, fast and easy reproducible procedure.

The relationship between coronary artery occlusion-induced arrhythmias and myocardial cyclic nucleotide levels in the anaesthetized rat.

The aims of this study were to determine whether a relationship exists between the occurrence of coronary artery occlusion-induced arrhythmias in the anaesthetized rat and the levels of cyclic AMP and cyclic GMP in both normal and ischaemic myocardium, and to assess whether such arrhythmias were modified by pretreatment with the phosphodiesterase inhibitors, quazodine and isobutyl methylxanthine (IBMX), or with the butyryl derivatives of cyclic AMP and cyclic GMP. At 5 min after coronary artery ligation (when only a few arrhythmias had occurred) both cyclic AMP and cyclic GMP levels were elevated in normal myocardium whereas in ischaemic tissue only cyclic AMP was raised. As the peak of the arrhythmic activity and after cessation of the arrhythmias, i.e. at 10 and 30 min post-ligation respectively, levels of both nucleotides had fallen in ischaemic although not in normal tissue. The severity of these occlusion-induced arrhythmias was exacerbated by pretreatment intravenously with quazodine, IBMX, dibutyryl cyclic AMP and dibutyryl cyclic GMP. Pretreatment with IBMX was also shown to elevate significantly both cyclic AMP and cyclic GMP content of left ventricular tissue before occlusion. None of the drug pretreatments markedly affected mean arterial blood pressure but heart rate was significantly increased following quazodine and IBMX administration. We conclude that in the pentobarbitone-anaesthetized rat the occurrence of occlusion-induced arrhythmias was not accompanied by a rise in cyclic nucleotide content of the ischaemic myocardium but agents which may elevate either myocardial cyclic AMP or cyclic GMP levels exacerbate such arrhythmias.