Analisi delle specie indicatrici applicata alle comunità a Stipa austroitalica Martinovsky e relative problematiche sin tassonomiche.

A method for the classification of the guide species of the different dry grassland communities characterised by Stipa austroitalica is proposed

Estabilidade da cor de doces em massa de polpa de umbu (Spondias Tuberosa Arr. Cam.) no estádio de maturação verde.

Os frutos de umbu (Spondias tuberosa Arr. Cam.) maduros são altamente perecíveis, e o aproveitamento deles no estádio de maturação verde, sob a forma de doce é uma interessante alternativa econômica, para o semi-árido nordestino. A conservação da cor, durante o armazenamento, constitui um fator de qualidade dos mais importantes para o consumo, e o presente trabalho objetivou avaliar sua alteração em função de diferentes formulações, embalagens (polipropileno e celofane) e temperaturas (33 e 43°C), por 90 dias de armazenamento. A adição de pectina e/ou xarope de glicose não alterou a luminosidade (L*), mas diminuiu os valores de a* (intensidade do vermelho ) e b*. (intensidade do amarelo). Verificou-se diminuição dos valores de L* a* e b*, notadamente para os doces armazenados à temperatura de 43°C e para a formulação sem adição de pectina. A embalagem não exerceu efeito significativo sobre L*( luminosidade), mas afetou a* e b* aos 90 dias de estocagem, em ambas as temperaturas. Os resultados globais indicaram o uso de pectina e xarope de glicose, embalagens de polipropileno e estocagem à temperaturas mais baixas como sendo as condições mais adequadas para preservação da cor

Gamma Radiation from PSR B1055-52

The telescopes on the Compton Gamma Ray Observatory (CCRO) have observed PSR B1055-52 a number of times between 1991 and 1998. From these data, a more detailed picture of the gamma radiation from this source has been developed, showing several characteristics which distinguish this pulsar: the light curve is complex; there is no detectable unpulsed emission; the energy spectrum is flat, with no evidence of a sharp high-energy cutoff up to greater than 4 GeV. Comparisons of the gamma-ray data with observations at longer wavelengths show that no two of the known gamma-ray pulsars have quite the same characteristics; this diversity makes interpretation in terms of theoretical models difficult

Conformational Reorganization of the SARS Coronavirus Spike Following Receptor Binding: Implications for Membrane Fusion

The SARS coronavirus (SARS-CoV) spike is the largest known viral spike molecule, and shares a similar function with all class 1 viral fusion proteins. Previous structural studies of membrane fusion proteins have largely used crystallography of static molecular fragments, in isolation of their transmembrane domains. In this study we have produced purified, irradiated SARS-CoV virions that retain their morphology, and are fusogenic in cell culture. We used cryo-electron microscopy and image processing to investigate conformational changes that occur in the entire spike of intact virions when they bind to the viral receptor, angiotensin-converting enzyme 2 (ACE2). We have shown that ACE2 binding results in structural changes that appear to be the initial step in viral membrane fusion, and precisely localized the receptor-binding and fusion core domains within the entire spike. Furthermore, our results show that receptor binding and subsequent membrane fusion are distinct steps, and that each spike can bind up to three ACE2 molecules. The SARS-CoV spike provides an ideal model system to study receptor binding and membrane fusion in the native state, employing cryo-electron microscopy and single-particle image analysis

Geothermal Heat Recovery Complex: Large-Scale, Deep Direct-Use System in a Low-Temperature Sedimentary Basin

This feasibility study is the first assessment of geothermal resources in the Illinois Basin (ILB). The breadth of previous, geologic-based research in the ILB supported this thorough determination of geothermal resources in the Mt. Simon Sandstone (MSS) and the techno-economics of establishing a geothermal energy system (GES) at the University of Illinois at Urbana-Champaign (U of IL). An integrated, multi-disciplinary scientific and engineering approach allowed simulations for both the belowground and aboveground components of the GES that would meet the required baseload of 2 MMBtu/hr at the end-user agricultural research facilities (ARFs). This assessment contributes to the broader discussion surrounding the U of IL’s goal to achieve net-zero carbon emissions by 2050. Furthermore, a rigorous evaluation of the ILB’s geological, hydrological, and thermal frameworks facilitated a broader assessment of the feasibility of applying deep direct-use (DDU) technologies at facilities (e.g., military installations, hospitals, and school campuses) in other geographical areas in the ILB, and in other sedimentary basins in midcontinent of the US.U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Geothermal Technologies Office Award Number DE-EE0008106Ope

Imaging Single Retrovirus Entry through Alternative Receptor Isoforms and Intermediates of Virus-Endosome Fusion

A large group of viruses rely on low pH to activate their fusion proteins that merge the viral envelope with an endosomal membrane, releasing the viral nucleocapsid. A critical barrier to understanding these events has been the lack of approaches to study virus-cell membrane fusion within acidic endosomes, the natural sites of virus nucleocapsid capsid entry into the cytosol. Here we have investigated these events using the highly tractable subgroup A avian sarcoma and leukosis virus envelope glycoprotein (EnvA)-TVA receptor system. Through labeling EnvA pseudotyped viruses with a pH-sensitive fluorescent marker, we imaged their entry into mildly acidic compartments. We found that cells expressing the transmembrane receptor (TVA950) internalized the virus much faster than those expressing the GPI-anchored receptor isoform (TVA800). Surprisingly, TVA800 did not accelerate virus uptake compared to cells lacking the receptor. Subsequent steps of virus entry were visualized by incorporating a small viral content marker that was released into the cytosol as a result of fusion. EnvA-dependent fusion with TVA800-expressing cells occurred shortly after endocytosis and delivery into acidic endosomes, whereas fusion of viruses internalized through TVA950 was delayed. In the latter case, a relatively stable hemifusion-like intermediate preceded the fusion pore opening. The apparent size and stability of nascent fusion pores depended on the TVA isoforms and their expression levels, with TVA950 supporting more robust pores and a higher efficiency of infection compared to TVA800. These results demonstrate that surface receptor density and the intracellular trafficking pathway used are important determinants of efficient EnvA-mediated membrane fusion, and suggest that early fusion intermediates play a critical role in establishing low pH-dependent virus entry from within acidic endosomes