423 research outputs found

    Progress report on identification of "organisms" in Lake Victoria responsible for echosounder traces

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    Exploratory fishing with midwater trawls in the pelagic zone of Lake Victoria generally yielded low quantities of fish even where dense traces appeared on the echosounder. Efforts to identify the "organisms" met with limited success. Types of gear were tested the midwater trawl, high-speed beam trawl, Lampara net, zooplankton net and SCUBA. This information plus that of earlier investigators indicate that the bulk of the traces are not caused by fish. The evidence however is not conclusive and further studies are warranted. Some recommendations for study are presented

    CHOLANE AND LANOSTANE DERIVATIVES: ANTIMICROBIAL EVALUATION

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    Steroids are natural compounds with several important applications in many fields of research, such as medicinal chemistry, pharmacology, supramolecular chemistry and nanotechnology.In particular, bile acids such as lithocholic acid (LCA) and ursodeoxycholic acid (UDCA) have been considered quite useful as starting points for a rich and different set of medicinal chemistry activities. Besides, the discovery of bioactive ingredients from plants and fungi is always the main target in medicinal chemistry. The lanostane-type triterpenoid 3b-hydroxylanosta-8,24-diene-21-oic acid (Trametenolic acid, TMA) was the main bioactive component of Gloeophyllum odoratum, which was reported to possess widely bioactivities, including tumor cell anti-proliferation effects (for example, human HL-60 leukemia, human KB epidermoid carcinoma, murine L1210 leukemia cells, Caski, HT-3, T-24, etc.), inhibition of enzyme activity (human thrombin, bovine trypsin and so on).Nevertheless, trametenolic acid was scarcely investigated as antimicrobial agent. Structurally, bile acids (LCA and UDCA) and trametenolic acid are similar since they may be regarded as consisting of two components, a rigid steroid nucleus and an aliphatic side chain possessing a carboxyl group. On the basis of these considerations, six new compounds bearing a guanidine moiety in their side chain were synthesized using LCA, UDCA and TMA as starting materials. The parent bile acids, TMA and their resulting derivatives were evaluated for antimicrobial activity against S. aureus, B. subtilis and M. smegmatis. The derivative 3a-hydroxy-23-guanidino-5b-cholane showed the best activity, with MIC values of 12.5 \u3bcM against S. aureus, 5 \u3bcM against B. subtilis and 50 \u3bcM against M. smegmatis. The cytotoxic activity of bile acids, trametenolic acid and derivatives was also evaluated against HT-29 cell lin

    Tele-Psychiatry Assessment of Post-traumatic Stress Symptoms in 100 Patients With Bipolar Disorder During the COVID-19 Pandemic Social-Distancing Measures in Italy

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    The acute phase of the COrona VIrus Disease-19 (COVID-19) emergency determined relevant stressful burdens in psychiatric patients, particularly those with chronic mental disorders such as bipolar disorder (BD), not only for the threat of being infected but also for the strict lock-down and social-distancing measures adopted, the economic uncertainty, and the limited possibilities to access psychiatric services. In this regard, telepsychiatry services represented a new important instrument that clinicians could adopt to monitor and support their patients. The aim of the present study was to investigate acute post-traumatic stress symptoms (PTSS) reported by patients with BD followed in the framework of a telepsychiatry service, set up in the acute phase of the COVID-19 outbreak at the psychiatric clinic of the University of Pisa (Italy). A sample of 100 patients were consecutively enrolled and assessed by the IES-r, GAD-7, HAM-D, and YMRS. Patients reported a mean (±SD) IES-r total score of 18.15 ± 13.67. Further, 17% of the sample reported PTSS (IES-r > 32), 17% depressive symptoms (HAM-D > 17), and 26% anxiety symptoms (GAD-7 > 10). Work and financial difficulties related to the COVID-19 pandemic and anxiety symptoms appeared to be positively associated with the development of acute PTSS. Acute manic symptoms appeared to be protective. The data of the present study suggest the relevance of monitoring patients with BD exposed to the burden related to the COVID-19 outbreak for prompt assessment and treatment of PTSS

    Observation of Fragile-to-Strong Dynamic Crossover in Protein Hydration Water

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    At low temperatures proteins exist in a glassy state, a state which has no conformational flexibility and shows no biological functions. In a hydrated protein, at and above 220 K, this flexibility is restored and the protein is able to sample more conformational sub-states, thus becomes biologically functional. This 'dynamical' transition of protein is believed to be triggered by its strong coupling with the hydration water, which also shows a similar dynamic transition. Here we demonstrate experimentally that this sudden switch in dynamic behavior of the hydration water on lysozyme occurs precisely at 220 K and can be described as a Fragile-to-Strong dynamic crossover (FSC). At FSC, the structure of hydration water makes a transition from predominantly high-density (more fluid state) to low-density (less fluid state) forms derived from existence of the second critical point at an elevated pressure.Comment: 6 pages (Latex), 4 figures (Postscript

    Implementation of a sensorized neonatal head model for gynechological training

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    During labor it is very important to know the exact position and orientation of the fetal head when descending the birth canal. Indeed, incorrect evaluations may lead to dangerous situations for both the infant and the mother. Usually, gynecologists and midwives rely on their experience to determine the head position and to evaluate the risk level of each delivery. In this context, it is essential to train new physicians and midwives to correctly manage different types of delivery. Here, we present the design and implementation of a realistic sensorized neonatal head that could be used on low-cost birth simulators for training and evaluation of residents and midwifery students

    Toward Smart Building Design Automation: Extensible CAD Framework for Indoor Localization Systems Deployment

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    Over the last years, many smart buildings applications, such as indoor localization or safety systems, have been subject of intense research. Smart environments usually rely on several hardware nodes equipped with sensors, actuators, and communication functionalities. The high level of heterogeneity and the lack of standardization across technologies make design of such environments a very challenging task, as each installation has to be designed manually and performed ad-hoc for the specific building. On the other hand, many different systems show common characteristics, like the strict dependency with the building floor plan, also sharing similar requirements such as a nodes allocation that provides sensing coverage and nodes connectivity. This paper provides a computer-aided design application for the design of smart building systems based on the installation of hardware nodes across the indoor space. The tool provides a site-specific algorithm for cost-effective deployment of wireless localization systems, with the aim to maximize the localization accuracy. Experimental results from real-world environment show that the proposed site-specific model can improve the positioning accuracy of general models from the state-of-the-art. The tool, available open-source, is modular and extensible through plug-ins allowing to model building systems with different requirements

    Altered inflammasome machinery as a key player in the perpetuation of Rett syndrome oxinflammation

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    Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the X-linked MECP2 gene. RTT patients show multisystem disturbances associated with an oxinflammatory status. Inflammasomes are multi-protein complexes, responsible for host immune responses against pathogen infections and redox-related cellular stress. Assembly of NLRP3/ASC inflammasome triggers pro-caspase-1 activation, thus, resulting in IL-1β and IL-18 maturation. However, an aberrant activation of inflammasome system has been implicated in several human diseases. Our aim was to investigate the possible role of inflammasome in the chronic subclinical inflammatory condition typical of RTT, by analyzing this complex in basal and lipopolysaccharide (LPS)+ATP-stimulated primary fibroblasts, as well as in serum from RTT patients and healthy volunteers. RTT cells showed increased levels of nuclear p65 and ASC proteins, pro-IL-1β mRNA, and NLRP3/ASC interaction in basal condition, without any further response upon the LPS + ATP stimuli. Moreover, augmented levels of circulating ASC and IL-18 proteins were found in serum of RTT patients, which are likely able to amplify the inflammatory response. Taken together, our findings suggest that RTT patients exhibited a challenged inflammasome machinery at cellular and systemic level, which may contribute to the subclinical inflammatory state feedback observed in this pathology

    Scaling Laws for Mitotic Chromosomes

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    During mitosis in higher eukaryotes, each chromosome condenses into a pair of rod-shaped chromatids. This process is co-regulated by the activity of several gene families, and the underlying biophysics remains poorly understood. To better understand the factors regulating chromosome condensation, we compiled a database of mitotic chromosome size and DNA content from the tables and figures of >200 published papers. A comparison across vertebrate species shows that chromosome width, length and volume scale with DNA content to the powers ∼1/4, ∼1/2, and ∼1, respectively. Angiosperms (flowering plants) show a similar length scaling, so this result is not specific to vertebrates. Chromosome shape and size thus satisfy two conditions: (1) DNA content per unit volume is approximately constant and (2) the cross-sectional area increases proportionately with chromosome length. Since viscous drag forces during chromosome movement are expected to scale with length, we hypothesize that the cross-section increase is necessary to limit the occurrence of large chromosome elongations that could slow or stall mitosis. Lastly, we note that individual vertebrate karyotypes typically exhibit a wider range of chromosome lengths as compared with angiosperms

    Spatial-Related Community Structure and Dynamics in Phytoplankton of the Ross Sea, Antarctica

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    The Ross Sea exhibits the largest continental shelf and it is considered to be the most productive region in Antarctica, with phytoplankton communities that have so far been considered to be driven by the seasonal dynamics of the polynya, producing the picture of what is considered as the classical Antarctic food web. Nevertheless, the Ross Sea is made up of a complex mosaic of sub-systems, with physical, chemical, and biological features that change on different temporal and spatial scales. Thus, we investigated the phytoplankton community structure of the Ross Sea with a spatial scale, considering the different ecological sub-systems of the region. The total phytoplankton biomass, maximum quantum efficiency (Fv/Fm), size classes, and main functional groups were analyzed in relation to physical–chemical properties of the water column during the austral summer of 2017. Data from our study showed productivity differences between polynyas and other areas, with high values of biomass in Terra Nova Bay (up to 272 mg chl a m–2) and the south-central Ross Sea (up to 177 mg chl a m–2) that contrast with the HNLC nature of the off-shore waters during summer. Diatoms were the dominant group in all the studied subsystems (relative proportion ≥ 50%) except the southern one, where they coexisted with haptophytes with a similar percentage. Additionally, the upper mixed layer depth seemed to influence the level of biomass rather than the dominance of different functional groups. However, relatively high percentages of dinoflagellates (∼30%) were observed in the area near Cape Adare. The temporal variability observed at the repeatedly sampled stations differed among the sub-systems, suggesting the importance of Long-Term Ecological Research (L-TER) sites in monitoring and studying the dynamics of such an important system for the global carbon cycle as the Ross Sea. Our results provide new insights into the spatial distribution and structure of phytoplankton communities, with different sub-systems following alternative pathways for primary production, identifiable by the use of appropriate sampling scales

    Some polynomial special cases for the Minimum Gap Graph Partitioning Problem

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    We study various polynomial special cases for the problem of partitioning a vertex-weighted undirected graph into p connected subgraphs with minimum gap between the largest and the smallest vertex weight
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