Zinc modulation of basal and ß-adrenergically stimulated L-type Ca2+ current in rat ventricular cardiomyocytes: consequences in cardiac diseases.

Zinc exists in biological systems as bound and histochemically reactive free Zn(2+) in the nanomolar range. Zinc is required as either structural or catalytic component for a large number of enzymes. It also modulates current passage through many ion channels. Here, we reinvestigated the effects of extracellular and intracellular Zn(2+) on the L-type Ca(2+) current (I (CaL)) and its modulation by ß-adrenergic stimulation in rat ventricular cardiomyocytes. In the absence of Ca(2+) ions, Zn(2+) could permeate through the L-type channel at much lower concentrations and at a more positive voltage range, but with a lower permeability than Ca(2+). In the presence of Ca(2+), extracellular Zn(2+) demonstrated strong bimodal inhibitory effects on the I (CaL), with half-inhibition occurring around 30 nM, i.e., in the range of concentrations found in the plasma. Intracellular Zn(2+) also significantly inhibited the I (CaL) with a half-inhibitory effect at 12.7 nM. Moreover, ß-adrenergic stimulation was markedly reduced by intracellular Zn(2+) at even lower concentrations (<1 nM) as a consequence of Zn(2+)-induced inhibition of the adenylyl cyclase. All these effects appeared independent of redox variations and were not affected by dithiothreitol. Thus, both basal intracellular and extracellular Zn(2+) modulate transmembrane Ca(2+) movements and their regulation by ß-adrenergic stimulation. Considering that, in many pathological situations, including diabetes, the extracellular Zn(2+) concentration is reduced and the intracellular one is increased, our results help to explain both Ca(2+) overload and marked reduction in the ß-adrenergic stimulation in these diseases.

Evaluating frailty may complement APACHE II in estimating mortality in elderly patients admitted to the ICU after digestive surgery.

OBJECTIVE: To analyze whether frailty can improve the prediction of mortality in patients admitted to the ICU after digestive surgery. DESIGN: Prospective, observational, 6-month follow-up study of a cohort of patients admitted to the ICU between June 1, 2018, and June 1, 2019. SETTING: Surgical ICU of a third level hospital. PATIENTS: Series of successive patients older than 70 years who were admitted to the ICU immediately after a surgical intervention on the digestive system. 92 patients were included and 2 were excluded due to loss of follow-up at 6 months. INTERVENTIONS: Upon admission to the ICU, severity and prognosis were assessed by APACHE II, and fragility by the Clinical Frailty Scale and the modified Frailty Index. MAIN VARIABLES OF INTEREST: ICU, in-hospital and 6-month mortality. RESULTS: The model that best predicts mortality in the ICU is the APACHE II, with an area under the ROC curve (AUC) of 0.89 and a good calibration. The model that combines APACHE II and Clinical Frailty Scale is the one that best predicts in-hospital mortality (AUC: 0.82), significantly improving the prediction of isolated APACHE II (AUC: 0.78; Integrated Discrimination Index: 0.04). Frailty is a predictor of mortality at 6 months, being the model that combines Clinical Frailty Scale and Frailty Index the one that has shown the greatest discrimination (AUC: 0.84). CONCLUSIONS: Frailty can complement APACHE II by improving its prediction of hospital mortality. Furthermore, it offers a good prediction of mortality 6 months after surgery. For mortality in ICU, frailty loses its predictive power, whereas isolated APACHE II shows excellent predictive capacity.

Transcranial direct current stimulation's effect on novice versus experienced learning.

Transcranial direct current stimulation (TDCS) is a non-invasive form of brain stimulation applied via a weak electrical current passed between electrodes on the scalp. In recent studies, TDCS has been shown to improve learning when applied to the prefrontal cortex (e.g., Kincses et al. in Neuropsychologia 42:113-117, 2003; Clark et al. Neuroimage in 2010). The present study examined the effects of TDCS delivered at the beginning of training (novice) or after an hour of training (experienced) on participants' ability to detect cues indicative of covert threats. Participants completed two 1-h training sessions. During the first 30 min of each training session, either 0.1 mA or 2.0 mA of anodal TDCS was delivered to the participant. The anode was positioned near F8, and the cathode was placed on the upper left arm. Testing trials immediately followed training. Accuracy in classification of images containing and not-containing threat stimuli during the testing sessions indicated: (1) that mastery of threat detection significantly increased with training, (2) that anodal TDCS at 2 mA significantly enhanced learning, and (3) TDCS was significantly more effective in enhancing test performance when applied in novice learners than in experienced learners. The enhanced performance following training with TDCS persisted into the second session when TDCS was delivered early in training.

Evaluating frailty may complement APACHE II in estimating mortality in elderly patients admitted to the ICU after digestive surgery. / La evaluación de la fragilidad puede mejorar la predicción del APACHE II en pacientes ancianos ingresados en UCI tras cirugía digestiva.

OBJECTIVE: To analyze whether frailty can improve the prediction of mortality in patients admitted to the ICU after digestive surgery. DESIGN: Prospective, observational, 6-month follow-up study of a cohort of patients admitted to the ICU between June 1, 2018, and June 1, 2019. SETTING: Surgical ICU of a third level hospital. PATIENTS: Series of successive patients older than 70 years who were admitted to the ICU immediately after a surgical intervention on the digestive system. 92 patients were included and 2 were excluded due to loss of follow-up at 6 months. INTERVENTIONS: Upon admission to the ICU, severity and prognosis were assessed by APACHE II, and fragility by the Clinical Frailty Scale and the modified Frailty Index. MAIN VARIABLES OF INTEREST: ICU, in-hospital and 6-month mortality. RESULTS: The model that best predicts mortality in the ICU is the APACHE II, with an area under the ROC curve (AUC) of 0.89 and a good calibration. The model that combines APACHE II and Clinical Frailty Scale is the one that best predicts in-hospital mortality (AUC: 0.82), significantly improving the prediction of isolated APACHE II (AUC: 0.78; Integrated Discrimination Index: 0.04). Frailty is a predictor of mortality at 6 months, being the model that combines Clinical Frailty Scale and Frailty Index the one that has shown the greatest discrimination (AUC: 0.84). CONCLUSIONS: Frailty can complement APACHE II by improving its prediction of hospital mortality. Furthermore, it offers a good prediction of mortality 6 months after surgery. For mortality in ICU, frailty loses its predictive power, whereas isolated APACHE II shows excellent predictive capacity.

Unveiling unconventional magnetism at the surface of Sr2RuO4.

Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr2RuO4, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr2RuO4 is still ongoing, a deeper understanding of the Sr2RuO4 normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr2RuO4 in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr2RuO4 surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.

The effects of familiarity and group size on mating preferences in the guppy, Poecilia reticulata.

In recent years, it has become evident that frequency dependence in the attractiveness of a particular phenotype to mates can contribute to the maintenance of polymorphism. However, these preferences for rare and unfamiliar male phenotypes have only been demonstrated in small, controlled experiments. Here, we tested the preference for unfamiliar mates in groups of six to 96 individuals over 13 days, in the guppy (Poecilia reticulata). We observed individual behaviour in situ to test whether fish discriminate two unfamiliar individuals among many familiar ones. We found that unfamiliar males and females were preferred over the familiar fishes in all groups and that this effect decayed over time. Increasing group sizes and levels of sexual activity did not hamper the preference for unfamiliar mates, providing further support for the role of frequency dependent mate choice in the maintenance of trait polymorphism in natural populations.

Isolation of retro-transcribed RNA from in vitro Mycosphaerella fijiensis-infected banana leaves.

High polyphenol and polysaccharide levels in plant tissues such as banana fruit and leaves constitute a significant challenge to the extraction of sufficient amounts of high-quality RNA required for cDNA library synthesis and molecular analysis. To determine their comparative effectiveness at eliminating polyphenols, polysaccharides and proteins, three protocols for RNA extraction from in vitro banana plantlet leaves were tested: Concert(TM) Plant RNA isolation kit, a small-scale protocol based on Valderrama-Cháirez, and a modified version of the Valderrama-Cháirez protocol. RNA quantity and purity were evaluated by UV-spectrophotometry using DEPC-treated water and Tris-HCl, pH 7.5. Purity was greater using Tris-HCl. The Concert(TM) Plant protocol produced the poorest quality RNA. Reverse transcription into cDNAs from RNA isolated from in vitro banana plantlet leaves infected with Mycosphaerella fijiensis using the modified Valderrama-Cháirez protocol, followed by PCR using primers designed against gamma-actin from banana and M. fijiensis, yielded products of the anticipated size. In addition, this protocol reduced the processing time, lowered costs, used less expensive equipment, and could be used for other plants that have the same problems with high polyphenol and polysaccharide levels.

Efficacy and economic benefits of prophylactic treatments of newly felled bamboo.

Bamboo (Bambusa spp.) users in Laguna and Rizal, Philippines, were surveyed regarding their willingness to accept varying degrees of bamboo powderpost beetle, Dinoderus minutus (F.) (Coleoptera: Bostrichidae), damage. The efficacy of deltamethrin, permethrin, or disodium octaborate tetrahydrate in water or in kerosene was then assessed against beetles on freshly cut bamboo (Bambusa vulgaris Schrader ex Wendland). Adult D. minutus in groups of 100 were capable of inflicting 50% cross-sectional damage on 30-cm-long bamboo samples within a 4-wk test period. Deltamethrin (0.01% [AI]). in water or kerosene provided significantly better protection against D. minutus attack on bamboo for 5 wk than did all other treatments. The results from a survey were then used to assess the cost/benefit ratio for each prophylactic treatment. Successful prophylactic treatment provided up to a 12:1 return, illustrating the benefits of such treatments.

Development of the powderpost beetle (coleoptera: bostrichidae) at constant temperatures.

Development of Dinoderus minutus was studied under laboratory conditions at five constant temperatures (15, 18, 25, 28, and 30 degrees C) to estimate developmental thresholds and thermal requirements of the egg, larva, pupa, and egg-to-adult stages. Adults began to burrow along the grain into bamboo pieces within 24 h after cutting and continued across the grain. Female beetle oviposited an average of 9.1 eggs in the ensuing 24 h, all in the metaxylem. The average period for development of eggs, larva, and pupa were 5.4, 43.8, and 4.6 d at 30 degrees C, respectively. The development rate data were regressed through the x-axis to derive the thermal constants of 4.3, 6.8, and 4.5 degrees C and thermal requirements of 113.6, 909.1, and 96.2 DD to predict D. minutus egg oviposition to hatch, larva-to-pupa development, and adult emergence from pupa, respectively. The thermal threshold for egg-to-adult development was 6.4 degrees C, with total thermal requirements of 1,111.1 DD. Oviposition, emergence, and thermal requirements for development of the various stages of D. minutus may be used for postharvest pest management of bamboo.

Adsorption of p-nitrophenol on activated carbon fixed-bed.

Carbon fixed-beds are usually used to remove organic contaminants. Adsorption in a carbon filter is a dynamic, non-steady process which is not yet completely understood. The objective of this paper is to establish a methodology to simplify the study of this process based on the wave theory, rapid small-scale column test and experimental design/surface response analysis. The constant pattern wave hypothesis was confirmed by the experimental data. The influence of the inlet concentration of p-nitrophenol and the flow rate on dynamic adsorption was studied at 20 degrees C following a central composite design using a second-order model. Both parameters have an important influence on the response variables studied. The methodology used is a useful tool for studying the dynamic process and shows interactions that are difficult to verify by the classical step-by-step method.

Determination of the energy potential of gases produced in the pyrolysis processes of the vegetal carbon manufacture industry.

In this work, a pyrolysis plant located in Valverde de Leganes, Badajoz (SW Spain) was studied. At present, only the solid phase obtained by pyrolysis finds an application as domestic fuel. In order to analyze the feasibility of a further energetic exploitation of the plant under study, the gases flowing through the chimneys were collected at different times throughout the pyrolysis process. Next, they were characterized and quantified by gas chromatography, the energy potential of each of the gases being determined. According to the results obtained in this study, a total energy potential of 5.6 x 10(7) MJ (i.e., 1.78 MW(t)) might be generated yearly. Hence, considering an overall process yield equal to 20%, up to 358 KW(e) would be produced. This power would supply enough electric energy to the industry, the remaining being added to the common electric network.

Importance of lipids in the nutritional treatment of inflammatory diseases.

Over the last decades, scientific advances in the knowledge of anti-inflammatory properties of lipids have lead to the development of new formulas for enteral and parenteral nutrition. These products have been utilised as a treatment for a variety of inflammatory diseases. In this review we expose the effects of lipids used in enteral nutriton on different inflammatory pathologies such as inflammatory bowel disease, atherosclerosis, lung fibrosis, rheumatoid arthritis, and others. During inflammatory diseases, eicosanoids are produced from polyunsaturated fatty acids present in cellular membranes. Inflammatory activity of these molecules depends on the nature of their precursors: when arachidonic acid (n-6) is present, pro-inflammatory molecules are released, whereas eicosapentaenoic acid (n-3)-derived eicosanoids are weakly inflammatory. In this way, fish oils, rich in n-3 polyunsaturated fatty acids, increase the content of eicosapentaenoic-eicosanoids and decrease arachidonic acid in immune and endothelial cells leading to a lower inflammatory activity. Likewise, oleic acid exhibits anti-inflammatory effects by preventing the release of particular chemotactic molecules. In summary, enteral diets supplemented with n-3 polyunsaturated fatty acids and oleic acid benefits the treatment of patients with inflammatory pathologies, leading to better outcomes, and decreasing the doses of anti-inflammatory drugs, which exhibit important secondary effects.

Homogeneous Diffusion Solid Model as a Realistic Approach to Describe Adsorption onto Materials with Different Geometries.

In this work, the adsorption kinetics of p-nitrophenol (PNP) onto several commercial activated carbons (ACs) with different textural and geometrical characteristics was studied. For this aim, a homogeneous diffusion solid model (HDSM) was used, which does take the adsorbent shape into account. The HDSM was solved by means of the finite element method (FEM) using the commercial software COMSOL. The different kinetic patterns observed in the experiments carried out can be described by the developed model, which shows that the sharp drop of adsorption rate observed in some samples is caused by the formation of a concentration wave. The model allows one to visualize the changes in concentration taking place in both liquid and solid phases, which enables us to link the kinetic behaviour with the main features of the carbon samples.

Human-threatened ecosystem: new signs of groundwater connection between Yacyreta reservoir and Ibera wetland (South America).

Ibera wetland is one of the most pristine and singular ecosystems of South America. Satellite-derived thermal analysis of its lacustrine system supported the existence of a groundwater connection with the Yacyreta reservoir through basaltic fractures located along the ancient river bed of the Parana. The groundwater outflow would be located on the geological discontinuity of the eastern border of Ibera wetland, concretely Laguna Ibera and Laguna Luna-Disparo. This new sign of connection comes on top of the hydrological signs which already exist. A call to prudence recommends not extending the recently projected increase of the water level of Yacyreta reservoir. Deeper hydrogeological studies should analyze the hypothesis emerged from this study before modifying the water level of Yacyreta.

Release of bFGF, an endothelial cell survival factor, by osmotic shock.

PURPOSE: To test the effects of osmotic change on basic fibroblast growth factor (bFGF) release from cultured endothelial cells (ECs). METHODS: Bovine aortic and bovine retinal ECs were exposed to hypoosmotic shock for 2 minutes, were allowed to recover for 15 minutes, and had bFGF release assayed. The role of bFGF in cell recovery was assessed by including neutralizing antibody against bFGF or the addition of exogenous bFGF. Cell number and viability were determined under varying conditions. Apoptosis was assessed by immunoperoxidase detection of digoxigenin-labeled DNA. RESULTS: After shock and recovery, both ECs released significantly greater amounts of bFGF than untreated control. bFGF release after shock for 2 minutes was lower than release after shock and recovery. Bovine retinal endothelial (BRE) cell number was reduced at 48 hours after shock, recovery, and removal of released bFGF compared with cells left in the presence of released bFGF. Cell number was significantly lower when BRE cells were shocked and recovered in the presence of a neutralizing anti-bFGF antibody (P<0.05). Exogenous bFGF reversed this effect. Apoptosis was significantly increased in BRE cells shocked and recovered or in the presence of bFGF antibody (P<0.001). CONCLUSIONS: bFGF is released by cultured ECs in response to osmotically induced cell injury. These results support the concept of bFGF as a "wound" hormone and survival factor for ECs. In further compromised tissue, release of bFGF in this manner may play a role in the pathogenesis of disease.

Infection with different Trypanosoma cruzi populations in rats: myocarditis, cardiac sympathetic denervation, and involvement of digestive organs.

We tested four isolates of Trypanosoma cruzi to assess parasite virulence and ability to cause myocarditis, cardiac sympathetic denervation, and histopathologic alterations in organs of the digestive system. The susceptibility of rats depends on the population of T. cruzi, with the ABC strain and the CL-Brener clone killing all animals, regardless of the parasitemic pattern. All tested T. cruzi populations caused acute myocarditis, but failed to induce histologic alterations in the intestine. The Cl-Brener and ABC isolates caused esophageal myositis. The myocarditis caused by the ABC, CL-Brener, and Y isolates was severe, but resolution started at the end of the acute phase. In contrast, the Col 1.7 G2 clone induced mild and sustained myocarditis. Our results also showed that T. cruzi populations able to induce severe acute myocarditis caused marked sympathetic denervation, but recovery of normal cardiac histology and innervation occurred. The sustained myocarditis induced by Col 1.7 G2 clone failed to cause sustained denervation.

Determination of chlorophenols in drinking water with high resolution gas chromatography-tandem mass spectrometry.

A new method for the determination of sub-ppb levels of chlorophenols in drinking water by use of GC-MS-MS is proposed. Monitoring of these analytes for assurance of compliance with legally allowed limits can readily be accomplished by extraction as acetylated chlorophenols from low sample volumes (10 ml). Much lower detection limits can be achieved by preconcentrating 11 of sample using graphitized carbon cartridges for solid extraction. Appropriate selection of parent ions and fragmentation conditions ensures not only a high sensitivity, but also clean product ion spectra that allow positive identification of every species considered (polychlorophenol isomers included).

Ionic surfactant adsorption onto activated carbons.

The adsorption of sodium dodecyl sulfate onto a set of activated carbons from aqueous solutions has been studied in the low concentration range. The adsorption isotherms are reasonably well fitted by a double Langmuir equation but the calorimetry of adsorption enthalpies shows a rather wide distribution of energies. This distribution is related to direct adsorbate-adsorbent interactions in pores of different size, without noticeable contributions from the chemical nature of the surface. The adsorbate-adsorbent interaction free energy through water is evaluated using the model proposed by van Oss and co-workers for the interfacial free energy. The obtained results indicate that the calculated free energy is in good agreement with that found from application of the double Langmuir equation to the adsorption isotherms.

Free energy of interaction of sodium dodecyl sulfate in aqueous solution with carbon black surfaces.

The free energy of the adsorption process of an ionic surfactant from aqueous solutions onto a set of carbon blacks in the range of low concentrations was evaluated using the model proposed by van Oss and co-workers. The obtained results indicated that the free energy of interaction between adsorbent and adsorbate through water results mainly from Lifshitz-van der Waals and electrostatic interactions, and its value showed a good correspondence with that previously found from a combination of the classical measurements of adsorption isotherms and the Langmuir model.