Gas mixing system for imaging of nanomaterials under dynamic environments by environmental transmission electron microscopy

A gas mixing manifold system that is capable of delivering a stable pressure stream of a desired composition of gases into an environmental transmission electron microscope has been developed. The system is designed to provide a stable imaging environment upon changes of either the composition of the gas mixture or upon switching from one gas to another. The design of the system is described and the response of the pressure inside the microscope, the sample temperature, and sample drift in response to flow and composition changes of the system are reported. (C) 2014 AIP Publishing LLC

Bourgeois behavior and freeloading in the colonial orb web spider Parawixia bistriata (Araneae, Araneidae)

Spiders of the tropical American colonial orb weaver Parawixia bistriata form a communal bivouac in daytime. At sunset, they leave the bivouac and construct individual, defended webs within a large, communally built scaffolding of permanent, thick silk lines between trees and bushes. Once spiders started building a web, they repelled other spiders walking on nearby scaffolding with a "bounce" behavior. In nearly all cases (93%), this resulted in the intruder leaving without a fight, akin to the "bourgeois strategy," in which residents win and intruders retreat without escalated contests. However, a few spiders (6.5%) did not build a web due to lack of available space. Webless spiders were less likely to leave when bounced (only 42% left) and instead attempted to "freeload," awaiting the capture of prey items in nearby webs. Our simple model shows that webless spiders should change their strategy from bourgeois to freeloading satellite as potential web sites become increasingly occupied

Protective Response Mechanisms to Heat Stress in Interaction with High [CO2] Conditions in Coffea spp.

This work was supported by national funds from Fundacao para a Ciencia e a Tecnologia through the projects PTDC/AGRPRO/3386/2012, the research units UID/AGR/04129/2013 (LEAF) and UID/GEO/04035/2013 (GeoBioTcc), as well through the grant SFRH/BPD/47563/2008 (AT) co-financed through the POPH program subsidized by the European Social Fund. Brazilian funding from CAPES (grams PDSE: 000427/2014-04, W.P. Rodrigues; 0343/2014-05, MM; 12226/12-2, LM), CNPq and Fapemig (fellowships to FDM, FP, and EC) are also greatly acknowledged.Modeling studies have predicted that coffee crop will be endangered by future global warming, but recent reports highlighted that high [CO2] can mitigate heat impacts on coffee. This work aimed at identifying heat protective mechanisms promoted by CO2 in Coffea arabica (cv. Icatu and IPR108) and Coffea canephora cv. Conilon CL153. Plants were grown at 25/20 degrees C (day/night), under 380 or 700 mu L CO2 L-1, and then gradually submitted to 31/25, 37/30, and 42/34 degrees C. Relevant heat tolerance up to 37/30 degrees C for both [CO2] and all coffee genotypes was observed, likely supported by the maintenance or increase of the pools of several protective molecules (neoxanthin, lutein, carotenes, ohtocopherol, HSP70, raffinose), activities of antioxidant enzymes, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), and the upregulated expression of some genes (ELIP, Chaperonin 20). However, at 42/34 degrees C a tolerance threshold was reached, mostly in the 380 -plants and Icatu. Adjustments in raffinose, lutein, beta-carotene, alpha-tocopherol and HSP70 pools, and the upregulated expression of genes related to protective (FLIPS, HSP70, Chape 20, and 60) and antioxidant (CAT, CuSOD2, APX Cyt, APX ChI) proteins were largely driven by temperature. However, enhanced [CO2] maintained higher activities of GR (Icatu) and CAT (Icatu and IPR108), kept (or even increased) the Cu,Zn-SOD, APX, and CAT activities, and promoted a greater upregulation of those enzyme genes, as well as those related to HSP70, ELIPs, Chaperonins in CL153, and Icatu. These changes likely favored the maintenance of reactive oxygen species (ROS) at controlled levels and contributed to mitigate of photosystem II photoinhibition at the highest temperature. Overall, our results highlighted the important role of enhanced [CO2] on the coffee crop acclimation and sustainability under predicted future global warming scenarios.publishersversionpublishe

A Western single-center experience with endoscopic submucosal dissection for early gastrointestinal cancers

Endoscopic submucosal dissection (ESD) has gained worldwide acceptance as a treatment for early gastrointestinal cancers (EGICs). However, the management of these tumors in the Western world is still mainly surgical. Our aim was to evaluate the safety and feasibility of ESD at a European center. Based on the knowledge transferred by one of the most experienced Japanese institutions, we conducted a pilot study on 25 consecutive patients with EGICs located in the esophagus (n = 3), stomach (n = 7), duodenum (n = 1), and colon (n = 14) at our tertiary center over a 2-year-period. The main outcome measurements were complete (R0) resection, as well as en-bloc resection and the management of complications. The R0 and en-bloc resection rates were 100% and 84%, respectively. There were three cases of bleeding and five cases of perforation. With a median follow up of 18 months, two recurrences were observed. We conclude that ESD for early esophageal and gastric cancers is feasible and effective, while colonic ESD requires more expertise

Structural and kinetic changes to small-pore Cu-zeolites after hydrothermal aging treatments and selective catalytic reduction of NO_x with ammonia

Three small-pore, eight-membered ring (8-MR) zeolites of different cage-based topology (CHA, AEI, RTH), in their proton- and copper-exchanged forms, were first exposed to high temperature hydrothermal aging treatments (1073 K, 16 h, 10% (v/v) H_2O) and then to reaction conditions for low temperature (473 K) standard selective catalytic reduction (SCR) of NO_x with ammonia, in order to study the effect of zeolite topology on the structural and kinetic changes that occur to Cu-zeolites used in NO_x abatement. UV-visible spectra were collected to monitor changes to Cu structure and showed that band intensities for isolated, hydrated Cu^(2+) cations (∼12 500 cm^(−1)) remain constant after hydrothermal aging, but decrease in intensity upon subsequent exposure to low temperature SCR reaction conditions. Standard SCR rates (per Cu, 473 K), activation energies, and reaction orders are similar between Cu-AEI and Cu-CHA zeolites before and after hydrothermal aging, although rates are lower after hydrothermal aging as expected from the decreases in intensity of UV-visible bands for Cu^(2+) active sites. For Cu-RTH, rates are lower (by 2–3×) and apparent activation energies are lower (by ∼2×) than for Cu-AEI or Cu-CHA. These findings suggest that the RTH framework imposes internal transport restrictions, effectively functioning as a one-dimensional framework during SCR catalysis. Hydrothermal aging of Cu-RTH results in complete deactivation and undetectable SCR rates, despite X-ray diffraction patterns and Ar micropore volumes (87 K) that remain unchanged after hydrothermal aging treatments and subsequent SCR exposure. These findings highlight some of the differences in low temperature SCR behavior among small-pore Cu-zeolites of different topology, and the beneficial properties conferred by double six-membered ring (D6R) composite building units. They demonstrate that deleterious structural changes to Cu sites occur after exposure to hydrothermal aging conditions and SCR reactants at low temperatures, likely reflecting the formation of inactive copper-aluminate domains. Therefore, the viability of Cu-zeolites for practical low temperature NO_x SCR catalysis cannot be inferred solely from assessments of framework structural integrity after hydrothermal aging treatments, but also require Cu active site and kinetic characterization after hydrothermally aged zeolites are exposed to low temperature SCR reaction conditions

Novel thermostable xylanase GH10 from Malbranchea pulchella expressed in Aspergillus nidulans with potential applications in biotechnology

Background: The search for novel thermostable xylanases for industrial use has intensified in recent years, and thermophilic fungi are a promising source of useful enzymes. The present work reports the heterologous expression and biochemical characterization of a novel thermostable xylanase (GH10) from the thermophilic fungus Malbranchea pulchella, the influence of glycosylation on its stability, and a potential application in sugarcane bagasse hydrolysis.Results: Xylanase MpXyn10A was overexpressed in Aspergillus nidulans and was active against birchwood xylan, presenting an optimum activity at pH 5.8 and 80°C. MpXyn10A was 16% glycosylated and thermostable, preserving 85% activity after 24 hours at 65°C, and deglycosylation did not affect thermostability. Circular dichroism confirmed the high alpha-helical content consistent with the canonical GH10 family (β/α)8 barrel fold observed in molecular modeling. Primary structure analysis revealed the existence of eight cysteine residues which could be involved in four disulfide bonds, and this could explain the high thermostability of this enzyme even in the deglycosylated form. MpXyn10A showed promising results in biomass degradation, increasing the amount of reducing sugars in bagasse in natura and in three pretreated sugarcane bagasses.Conclusions: MpXyn10A was successfully secreted in Aspergillus nidulans, and a potential use for sugarcane bagasse biomass degradation was demonstrated.Peer reviewedMicrobiology and Molecular Genetic

Multicenter double blind trial of autologous bone marrow mononuclear cell transplantation through intracoronary injection post acute myocardium infarction – MiHeart/AMI study

Background: Myocardial infarction remains as a major cause of mortality worldwide and a high rate of survivors develop heart failure as a sequel, resulting in a high morbidity and elevated expenditures for health system resources. We have designed a multicenter trial to test for the efficacy of autologous bone marrow (ABM) mononuclear cell (MC) transplantation in this subgroup of patients. The main hypothesis to be tested is that treated patients will have a significantly higher ejection fraction (EF) improvement after 6 months than controls. Methods: A sample of 300 patients admitted with ST elevation acute myocardial infarction (STEMI) and left ventricle (LV) systolic dysfunction, and submitted to successful mechanical or chemical recanalization of the infarct-related coronary artery will be selected for inclusion and randomized to either treated or control group in a double blind manner. The former group will receive 100 x 106 MC suspended in saline with 5% autologous serum in the culprit vessel, while the latter will receive placebo (saline with 5% autologous serum). Implications: Many phase I/II clinical trials using cell therapy for STEMI have been reported, demonstrating that cell transplantation is safe and may lead to better preserved LV function. Patients with high risk to develop systolic dysfunction have the potential to benefit more. Larger randomized, double blind and controlled trials to test for the efficacy of cell therapies in patients with high risk for developing heart failure are required.Brazilian Ministry of Science and Technology (MCT)/The Financing Agency for Studies and Projects (FINEP