786 research outputs found

    Vir probus.

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    Volume especial, 1900, p. 36-37

    Recurrent Appendicitis in Children: The Impact of a Poorly Known Disease

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    Chronic and recurrent appendicitis is rare in pediatric patients and can be easily misdiagnosed due to its unusual presentation and low incidence rate. We present the case of an 11-year-old male with recurrent right lower quadrant (RLQ) pain persisting for 19 months. The patient experienced pain flare-ups accompanied by paleness and gait limp, without fever or other symptoms. Despite extensive medical examinations, including imaging and endoscopy, a definitive diagnosis remained elusive. As serial abdominal ultrasounds reported an appendix at the upper limit of the normal caliber and symptoms persisted despite medical therapy, a diagnostic laparoscopy was performed, revealing a congested ileocecal appendix with erosions and granulocytic inflammatory infiltrate, consistent with appendicitis. Post appendectomy, the patient's symptoms resolved, significantly improving his quality of life (QoL), as evidenced by the DISABKIDS Chronic Generic Module (DCGM). This case underscores the challenges in diagnosing chronic and recurrent appendicitis, emphasizing the need for improved awareness, case definitions, and research to better understand and manage these conditions. Moreover, the report highlights the substantial impact of such conditions on patients' physical, social, and psychological well-being using the only health-related QoL instrument developed across cultures for children with chronic diseases: the DCGM

    Sustainability of treatment technologies for industrial biowastes effluents

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    Despite the huge efforts to develop efficient technologies for the treatment of recalcitrant biowastes and other emerging pollutants, selecting the most sustainable method among the possible alternatives is still a formidable task. This is mainly because of the integration of technical, economic, environmental, and social criteria in decision-making process. Traditionally, various multi-criteria decision-making approaches have been adopted to integrate innumerable criteria for environmental applications. In this study, we have examined the fuzzy-Delphi approach to evaluate seventeen parameters for integrating technical, economic, environmental and social criteria in order to rank the nine treatment technologies divided in two categories (physico-chemical and biological processes). The results of this study indicated that although efficiency of treatment methods is the most important criterion, but contribution of other sustainability criteria should also be considered because they are of high importance for the selection of sustainable wastewater treatment methods. As per our proposed framework on membrane technologies (among the many other physico-chemical methods) and anaerobic sludge blanket technology (among the biological treatment methods) are the most promising approaches for the treatment of highly polluted emerging industrial pollutants. The findings of this study are fully supported by the consensus achieved by a group of fifty experts from nineteen different countries. Opportunities for the improvement of the methods as per data generated are discussed.publishe

    Thermal fatigue assessment of components made with particulate polymer composites

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    Many appliance materials are made of PMMA/Si acrylic casting dispersion. In these situations, failure can occur by thermal fatigue induced by severe temperature variations such as alternating flows of cold and hot water. This paper is concerned with the numerical analysis of the thermal stresses in three composites with different volume fractions of filler and particle size. Their trade marks are Asterite, Amatis and Ultra-quartz. Cosmos/M finite element method software was used to study the influence of the cold and hot water temperatures as well as the time of interruption of water flow in the transition between hot and cold water on thermal stresses. Residual stresses were measured and superimposed to thermal stress in fatigue analysis. Typical defects in the corner of holes produced by drilling were predicted using experimental fatigue lives and da/dN curves. Based on predicted defects thermal fatigue assessment of commercially available sinks made with the three materials mentioned earlier was done by taking into account the influence of both cyclic thermal and static residual stresses induced by the manufacturing process.http://www.sciencedirect.com/science/article/B6V55-4DF4C7S-2/1/e913309acfd159679eb06b390853e5e

    Green synthesis of nanomaterials - a scientometric assessment

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    The green synthesis of engineered nanomaterials (NMs) has deserved an enormous academic interest and huge financial investments during the last decades. However, this prominent position has not been followed by the rapid commercialization of NMs for real applications thus rendering their practical usefulness very doubtful and the appropriateness of novel investments in the field highly questionable. The present manuscript presents the first scientometric study on the green synthesis of NMs aiming to survey the scientific progress in this particular field and identify its main gaps while providing applicable suggestions to facilitate the knowledge transfer from laboratories to real full scale production and applications. The research on green synthesis of nanomaterials published in Web of Science during the period 1991–2019 is here carefully analyzed. Overall, 9 scientometric indicators are employed to interpret the results retrieved from the 8761 documents collected. It is found that 107 countries and nearly 22,400 authors have contributed to this subject, hence highlighting the relevance of this topic. The keywords spectrum is dominated by the term “nanoparticle” which full adoption takes place at the beginning of the 21st century. Some few years later, a batch of words like “silver nanoparticle”, “gold nanoparticle” and “nanocomposite” reaches a significant impact reflecting the emergence of commercial applications for these nanomaterials. It is only in 2009 that the keyword “green synthesis” gains strength, followed then by “biosynthesis” in 2010, making it evident a trend towards environmentally friendly reagents. The number of publications on green synthesis of nanomaterials displays up to now a sigmoidal like growth pattern, which points actually to a decrease on new arrivals, thus suggesting a possible forthcoming decline in this field. However, the analysis carried out in the present work allows identifying various gaps related to sustainability, which, if appropriately addressed, may contribute to a resurgence of the research on nanomaterials synthesis while fostering more frugal approaches on material synthesis tendencies.publishe

    Fatigue behaviour of nanoclay reinforced epoxy resin composites

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    Nanoparticle filling is a feasible way to increase the mechanical properties of polymer matrices. Abundant research work has been published in the last number of years concerning the enhancement of the mechanical properties of nanoparticle filled polymers, but only a reduced number of studies have been done focusing on the fatigue behaviour. This work analyses the influence of nanoclay reinforcement and water presence on the fatigue behaviour of epoxy matrices. The nanoparticles were dispersed into the epoxy resin using a direct mixing method. The dispersion and exfoliation of nanoparticles was characterised by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fatigue strength decreased with the nanoclay incorporation into the matrix. Fatigue life of nanoclay filled composites was significantly reduced by the notch effect and by the immersion in water

    Changes associated with Na,K-ATPase in brain, kidney, heart and liver of the spontaneously diabetic Goto-Kakizaki rat

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    Alterations in Na,K-ATPase activity, in isoenzyme expression and/or number of units of the pump present in the plasma membrane have been associated with diabetes. These changes were described in different organs and tissues such as brain, heart, kidney, among others, and may result from altered insulin levels. However, the vast majority of studies were conducted in animal models of chemically induced diabetes, which are not consensual models for type 2 diabetes (T2D). The major goal of this work was to investigate putative modifications in Na,K-ATPase enzymatic activity or expression in brain, kidney, heart and liver in T2D. The Goto-Kakizaky rat (GK) strain was used as a model of spontaneously developed T2D, and Wistar rats as controls. Na,K-ATPase activity was assessed by the hydrolysis of ATP (Pi formed in the presence/absence of ouabain was measured using a colorimetric assay) and the isoenzymatic expression by Westernblot. A decrease in Na,K-ATPase activity in renal and cardiac tissues from GK comparatively to controls (55.7% and 77.5%, respectively) was observed. The pump activity was similar in liver and brain tissues. In renal tissue, expression of α1-Na,K-ATPase was similar between GK and controls but α2- was 2.3x higher and α3- was detected only in GK. Contrastingly a decreased expression of α1- (49.5%) and α2-isoforms (67.6%) was found in cardiac tissue. Despite similar Na,K-ATPase activity in liver and brain tissues, α1-isoform expression was decreased (33.9%) in the liver from GK while in the brain an increase of α1-isoform (~2x) together with a decrease of α2-isoform (14.0%) expressions were observed. It is unclear, except maybe for cardiac tissue where lower expression is potentially underlying the diminished pump activity in GK, whether the changes in isoenzyme expression is a key factor for differential Na,K-ATPase activity. Being responsive to complex regulation, other regulatory mechanisms may contribute to the impaired activity observed in kidney and heart. These results have uncover changes in Na,K-ATPase activity and/or enzymatic expression in GK brain, kidney, heart and liver that may contribute to the undesirable conditions associated with T2D. This work highlight the relevance of further investigation about Na,K-ATPase regulation and role in physiopathology of T2D

    Fatigue life predictions in polymer particle composites

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    This paper presents a study on fatigue life predictions in three polymer particle composites with different volume fractions of filler and different particle sizes. Central hole notched specimens were analysed using a fracture mechanics approach. A solution for the stress intensity factor of corner cracks at a hole was obtained using the finite element method and considering quarter-circular and quarter-elliptical cracks of different sizes. The solution was compared with a literature solution and significant differences were found. Fatigue crack propagation tests were performed at room temperature and constant loading amplitude, for stress ratios R=0 and R=-0.75. Finally, fatigue lives, crack shape evolution and final crack length were predicted assuming an initial crack size and considering that the crack maintains a quarter-elliptical shape. The comparison with experimental fatigue lives indicated the presence of initial defects larger than the silica particles; however, these large sizes can be explained by the residual stresses measured near the hole.http://www.sciencedirect.com/science/article/B6V35-454FDJ5-7/1/4231c9abb6a4b1b364cde431359b1e1

    Monitoramento de abelhas silvestres (Hymenoptera: Apoidea) em SAFs com dendê (Elaeis guineensis Jacq.) no município de Tomé-Açu, PA.

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    Dentre as oleaginosas cultivadas no Brasil, o dendezeiro (Elaeis guineensis Jacq.) é a que mais produz óleo por unidade de área. A forma tradicional de cultivo do dendezeiro é o monocultivo, porém na Amazônia os Sistemas Agroflorestais (SAFs) são opções atrativas para o uso do solo, por apresentarem maior similaridade com a floresta e já existirem iniciativas de cultivo de dendê nesse sistema. Visando avaliar a presença de polinizadores em SAFs com dendê no Município de Tomé-Açu (PA), foram coletadas abelhas silvestres com armadilhas aromáticas, pan-traps e rede entomológica, na época seca e chuvosa, nos anos de 2009 e 2010. Foram capturadas 967 abelhas, de 27 grupos taxonômicos. As armadilhas aromáticas capturaram 673 indivíduos, de 16 espécies, dos gêneros Euglossa (8), Eulaema (5), Exaerete (2) e Eufriesea (1), além de 21 morfoespécies. Com pan-traps foram capturadas 144 abelhas de 3 famílias: Apidae (109), Halictidae (29) e Andrenidae (6). Basicamente o mesmo grupo de abelhas capturadas com pan-traps, foi coletado com rede entomológica. Os SAFs apresentaram maior diversidade e abundância de abelhas em relação aos demais sistemas avaliados.Editores técnicos: Roberto Porro, Milton Kanashiro, Maria do Socorro Gonçalves Ferreira, Leila Sobral Sampaio e Gladys Ferreira de Sousa

    Editorial: Animal Poisoning and Biomarkers of Toxicity

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    The worldwide incidence of animal poisoning is unknown. Despite reports pieced together by networks of veterinary clinics and poison control centers, their coverage is usually limited due to widespread under-reporting of cases (1–3). There are several reasons for this reality, being one of the major the wide gaps of knowledge regarding toxicosis agents and their profile (particularly in terms of toxicity mechanisms), since these encompass an extensive variety of synthetic chemicals, molecules of plant and animal origin, as well as drugs (both of use and abuse) (1–3). Together with the lack of specific and sensitive analytical techniques for their detection and quantification, this reality leads to reports being usually submitted in incomplete form, and presented in a case-by case manner (4–6). This situation has created uncertainty when comparing poisoning with other types of clinical findings, such as infectious diseases, traumatic injuries or malignant neoplasms, since toxicosis would come out, at least apparently, as an uncommon cause of disease (3). This has led to appeals for more cooperation and information sharing between countries and institutions (1, 3), even inside “data-rich regions” (7), which typically include North America and Europe. The disproportionately higher volumes of available information in these areas also contribute to introduce geographic biases in available information (2). This reality is perfectly illustrated by European and North American floras, that, despite their disparity in the number of hazardous species (Europe has a much lower number), are both fairly well characterized. Contrastingly, African flora, which is at least as rich in hazardous species as the North American, has been reduced to seemingly anecdotal reports (8, 9). Even in Europe, despite the already mentioned lower number of hazardous species, the number of poisonings (affecting livestock and companion animals) attributed to wild, illicit drug or houseplants (mostly by ingestion) is considerable, since they contain chemical substances in sufficient quantities to cause toxic effects. In the particular case of companion animals, the majority of reported cases refers ingestion of ornamental plants (as opposed to wild), as the source of toxicity, particularly at certain times of the year (8). In addition to plant toxicity, available information indicates that the incidence of animal toxicosis from all causes does not seem to be declining. In the 2010's, a series of reports (10–12) detailed the prevalent toxicants affecting different groups of animals. The authors identified toxic plants and mycotoxins as the most common toxic agents involved in livestock and poultry poisoning, with additional cases being reported for metals (Cu, Pb), pesticides (endosulfan, lindane), and industrial chemicals (e.g., dioxins, polychlorinated biphenyls, dibenzofurans) (11). Regarding companion animals, frequent causes of poisoning include the exposure to anticoagulant rodenticides (coumarins), herbicides (paraquat), and insecticides (organophosphates, carbamate, strychnine, metaldehyde). Also, the inadequate use of human and veterinary pharmaceuticals, and the exposure to household products accounted for a noteworthy part of registered toxicosis reports (10). Wildlife species are frequently victims of primary (deliberate), but also of secondary poisonings (typically top predators). Metals and metalloids (Pb, Zn, As, Cu, Tl, Cd, and Hg) and pesticides (mostly anticholinergics and anticoagulants) were identified as frequent, often fatal, poisoning agents. In aquatic ecosystems, point or diffuse sources of chemicals and/or from industrial, agricultural, and urban runoff contribute to poisoning incidents. Additionally, chemicals released during environmental catastrophes (which could include any of the previous categories) are a significant cause of poisoning. The type of toxicants described more than two decades ago are, in a large number of cases, not the same, since, at least in the case of synthetic chemicals (including pharmaceuticals) many of them, were banned by legislation. However, new molecules (whose harmlessness is still to be entirely proven) were developed, manufactured in large scales, and started being used in their place. Despite this (partial) change of agents, current reports indicate the continuity of poisoning events toward animals (4, 6, 13–17). Consequently, researchers in this area face the paramount task of unraveling the underlying mechanisms (such as the toxicokinetics and toxicodynamics models and the adverse outcome pathways-AOPs) of new toxicants created by the continuous outpouring of new synthetic chemicals developed for the industry, the agrobusiness and household products market, as well as the growing sector of natural extracts. Biomarkers can act as indicators or signallers of events occurring in biological systems (18). By permitting the measurement of changes in molecules, biochemical processes, cells, tissues, organs and entire organisms (encompassing physiology, pathology, or behavior) in response to external insult, they provide nuclear knowledge in order to deliver accurate diagnosis under the form of biomarkers of exposure, effects and susceptibility, as well as enabling to delineate therapeutic interventions, and the improvement of key aspects of the drug development process (19). Additionally, they can be noninvasive and can translate between species. In fact, some authors consider that the most valuable are those that can be simultaneously used in animals and humans (19). In this Research Topic of Frontiers in Veterinary Science/Veterinary Pharmacology and Toxicology, 7 manuscripts were published: 1 Review, 5 original Research Articles and 1 Brief Research Report, whose main results and contributions are briefly presented below
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