589 research outputs found
[PdCl2{8-(di-tert-butylphosphinooxy)quinoline)}]: a highly efficient catalyst for Suzuki-Miyaura reaction
The complex [PdCl2(P-N)] containing the basic and sterically demanding 8-(di-tert-butylphosphinooxy)quinoline ligand (P-N) is a highly efficient catalyst for the coupling of phenylboronic acid with aryl bromides or aryl chlorides. The influence of solvent and base has been investigated, the highest rates being observed at 110 C in toluene with K2CO3 as the base. With aryl bromides the reaction rates are almost independent on the electronic properties of the para aryl substituents, on the contrary, reduced reaction rates are observed when bulky substituents are present on the substrate. Nevertheless the coupling of 2-bromo-1,3,5-trimethylbenzene with phenylboronic acid can be carried out to completion in 2 h using a catalyst loading of 0.02 mol %. Under optimized reaction conditions, turnover frequencies as high as 1900 h(-1) can be obtained in the coupling of 4-chloroacetophenone with phenylboronic acid: lower reaction rates are obtained with Substrates bearing EDG substituents on the aryl group. (C) 2009 Elsevier Ltd. All rights reserved
Demographic genetics of the endangered Amiata donkey breed
The demogenetic structure of the Amiata donkey, an endangered breed from Central Italy, was investigated using information from pedigrees. Genealogical data of 602 donkeys reared in Tuscany were recorded in a database and analysed by the computer package ENDOG. Population size increased from 89 subjects in 1995 to 503 (129 males and 374 females) in 2005. Animals were distributed among 152 herds, but the effective number of herds was 21, suggesting that a small number of herds provided stallions for the entire breed. The maximum number of traced generation was 4, the mean maximum generation was 1.14, the mean com- plete generation was 0.53, and the mean equivalent generation was 0.78. The average relatedness coeffi- cient (AR) in the 503 alive animals was 0.94% while the mean F was 0.29% so the effective population size was 172.41. Among 24 animals with a 4-generation history, 3 (12.5%) were 25% inbred. Although the incompleteness of genealogical information did not permit accurate inference of the current values of popu- lation genetic parameters, the present work represents a first step towards an efficient management of the breed
Usability Characteristics Assessment Protocol Applied to eTouch Ultrasound User-defined workflow Optimization Tool
AbstractThe Ultrasound (US) examination time reduction is an increasing compelling request in sonographer's everyday life. The increased number of patients and the cost reduction are two opposite forces, which can lead the sonographer to work faster without caring about scanning posture. The numerous repeated actions performed can easily lead to Work-related Musculoskeletal Disorders (WRMSD). The analysis of those problems has driven to the definition and implementation of eTouch tool: user-defined Macros appositively created, automatically and sequentially saved and performed in real time by pressing a button. The present work investigates ergonomics and usability performances of a portable US system (MyLabAlpha, Esaote S.p.A., Italy) by using eTouch as well as the classical manual interface in two clinical applications (Abdominal and Vascular). performed by a skilled sonographer on a healthy subject. is. Upper-body kinematic and muscle activation of the sonographer's left arm were recorded through an optoelectronic system (SmartDx400, BTS Spa, Italy) and a multi-channel Wireless Superficial Electromyography (SEMG, Freemg300, BTS Spa, Italy). The number of keystrokes used during the manual procedure was more than 3 times higher than the one with eTouch. This difference implied a reduction of US execution time when using eTouch in comparison with manual use of about 30%. Results of the upper-body kinematic showed that the arm was extended for less time intervals when using eTouch, whereas during the manual procedure there was a greater activation of the deltoid, responsible for the elevation of the shoulder and thus the extension of the arm. SEMG analysis showed that eTouch allowed a significant reduction of muscular activation, especially for the anterior deltoideus. Our findings showed that eTouch is recommendable for decreasing WRMSD risk
Effects of water stress on spectral reflectance of bermudagrass
In the south-central Italy, during summer rainfall does not supply a sufficient amount of water. Therefore, irrigation management during dry periods is important for maintaining turf quality. The hybrid bermudagrass (Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt–Davy) is known to represent the dominant warm-season turfgrass in warm to temperate climatic regions and its drought tolerance make bermudagrass a competitive turfgrass. A greenhouse experiment was conducted using uniform cores of hybrid bermudagrass, which were secured in a polyvinyl chloride cylinders and watered by constant sub-irrigation. The objectives of the present research were to measure the spectral reflectance with a new generation handheld spectroradiometer on hybrid bermudagrass and to explore various vegetation indices to be used as future detecting tool to study water stress in bermudagrass. Moreover, the potential uses of multivariate processing techniques for discriminating different water stress conditions in turfgrass has been investigated. Besides spectral indices, multivariate methods, although performed on a data set limited in terms of sample size, have shown a great potential for water stress monitoring in turfgrass and surely deserve further investigations. There are different indices that use distinct water absorption features independent of chlorophyll concentration, such as water index (WI = R900/R970) that has been reported to be a robust index of canopy water content and is used as an active indicator of changes in Leaf Relative Water Content (LRWC). Also, the ratio of WI with NDVI (WI/NDVI = (R900/R970)/((R800 − R680)/(R800 + R680)]) was found to be an effective indicator of water stress. Another vegetation index to detect water features is normalized difference water index (NDWI), designed to maximize reflectance of water by using green wavelengths. In our trial in bermudagrass the relationships studied, suggest that WI (900/970) and WI/NDVI, among the indices studied, are the more effective indicators of water stress. In fact, lower values of WI indicate higher water stress, while higher values of WI/NDVI indicate higher water stress levels
Ultrasound System Typologies, User Interfaces and Probes Design: A Review
he present review paper aims to give insights regarding what is available now, and will be in the next future, on the Market in terms of Ultrasound (US) system User Interfaces characteristics and peculiarities; US system typologies and probe typologies. Moreover, insights regarding ergonomics evaluation technologies and techniques for US systems, User Interface and transducers design evaluation, will be provided as well. The User interface ergonomics of US systems and probes is of primary importance due to the increased use in the everyday clinical practice even by non-sonographers, and the higher attention to the Work-related Musculoskeletal Disorders (WRMSD). A large overview and review of market data, side by side tests, websites, interviews to US users, marketing and sales professionals, scientific and educational publications was carried out in order to collect all available data as well as to show and describe them to the reader. Nowadays US market offers many different typologies of systems and probes, with different prices, features, quality level and targets of use. Users have to be aware to increase their level of knowledge in order to perform the best choice in terms of price/performance ratio and in terms of ergonomics and workflow requirements. The same level of knowledge is necessary also for other stakeholders of the US imaging Lab and purchasing/test decision phases such as Clinical and Biomedical Engineers involved in technical decision related to capital equipment and their maintenance. Final users expect technical innovations every 6-12 months in order to ensure technical-clinical improvements and company commitment to research and customer focus. Such characteristics are important clues showing a fast moving of the US market from a capital equipment basis to a more mass-consumer approach characterized by fast innovations, quick obsolescence and consumer prone attitude to system rotation in order to have always the more up-to-date technology, product, probe available on the Market
Early-life nicotine or cotinine exposure produces long-lasting sleep alterations and downregulation of hippocampal corticosteroid receptors in adult mice
Early-life exposure to environmental toxins like tobacco can permanently re-program body structure and function. Here, we investigated the long-term effects on mouse adult sleep phenotype exerted by early-life exposure to nicotine or to its principal metabolite, cotinine. Moreover, we investigated whether these effects occurred together with a reprogramming of the activity of the hippocampus, a key structure to coordinate the hormonal stress response. Adult male mice born from dams subjected to nicotine (NIC), cotinine (COT) or vehicle (CTRL) treatment in drinking water were implanted with electrodes for sleep recordings. NIC and COT mice spent significantly more time awake than CTRL mice at the transition between the rest (light) and the activity (dark) period. NIC and COT mice showed hippocampal glucocorticoid receptor (GR) downregulation compared to CTRL mice, and NIC mice also showed hippocampal mineralocorticoid receptor downregulation. Hippocampal GR expression significantly and inversely correlated with the amount of wakefulness at the light-to-dark transition, while no changes in DNA methylation were found. We demonstrated that early-life exposure to nicotine (and cotinine) concomitantly entails long-lasting reprogramming of hippocampal activity and sleep phenotype suggesting that the adult sleep phenotype may be modulated by events that occurred during that critical period of life
Intracerebral Injection of Extracellular Vesicles from Mesenchymal Stem Cells Exerts Reduced Aβ Plaque Burden in Early Stages of a Preclinical Model of Alzheimer's Disease
Bone marrow Mesenchymal Stem Cells (BM-MSCs), due to their strong protective and anti-inflammatory abilities, have been widely investigated in the context of several diseases for their possible therapeutic role, based on the release of a highly proactive secretome composed of soluble factors and Extracellular Vesicles (EVs). BM-MSC-EVs, in particular, convey many of the beneficial features of parental cells, including direct and indirect \u3b2-amyloid degrading-activities, immunoregulatory and neurotrophic abilities. Therefore, EVs represent an extremely attractive tool for therapeutic purposes in neurodegenerative diseases, including Alzheimer's disease (AD). We examined the therapeutic potential of BM-MSC-EVs injected intracerebrally into the neocortex of APPswe/PS1dE9 AD mice at 3 and 5 months of age, a time window in which the cognitive behavioral phenotype is not yet detectable or has just started to appear. We demonstrate that BM-MSC-EVs are effective at reducing the A\u3b2 plaque burden and the amount of dystrophic neurites in both the cortex and hippocampus. The presence of Neprilysin on BM-MSC-EVs, opens the possibility of a direct \u3b2-amyloid degrading action. Our results indicate a potential role for BM-MSC-EVs already in the early stages of AD, suggesting the possibility of intervening before overt clinical manifestations
Spatial changes in calcium signaling during the establishment of neuronal polarity and synaptogenesis.
- …