141 research outputs found

    Sun-photometric measurements of atmospheric turbidity variations caused by the Pinatubo aerosol cloud in the Himalayan region during the summer periods of 1991 and 1992

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    Measurements of direct solar irradiance were taken episodically on two days of September 1990 and regularly in the summer periods from July to October 1991 and from mid-July to mid-August 1992 at the Pyramid Laboratory (5050 m a.m.s.l.) situated at the foot of Mt. Everest (Nepal), using two examples of the Volz multispectral sunphotometer, model A. These sun-photometric measurements were analysed in terms of the Bouguer-Lambert-Beer law in order to determine the values of aerosol optical thickness at the three sun-photometric window-wavelengths. Examining these spectral series in terms of the well-known Ångström formula, the best-fit values of turbidity parameters a and b were calculated with great accuracy. From the measurements taken in September 1990, we found values of the aerosol optical thickness in good agreement with the mean values of the background aerosol optical depth measured at the Mauna Loa Observatory (Hawaii) during the four-year period from 1988 to 1991. The spectral values of the aerosol optical thickness determined during the summer of 1991 show that the mean daily values of parameter b increased abruptly from about 0.06 to more than 0.16 from July 26 to 28, 1991, and then varied between 0.09 and 0.16 during the rest of the measurement period. Simultaneously, parameter a was found to decrease from more than 1.25 to 0.39 towards the end of July and to vary between 0.40 and 0.78 during September. These large variations of both atmospheric turbidity parameters have been attributed to the growth of the aerosol particles and to the consequent changes in the size distribution curve of the Pinatubo aerosol particles. Analysing the variations of the stratospheric aerosol optical depth in terms of particle polydispersions consisting of a linear combination of a background aerosol monomodal model and a bimodal model representing the Pinatubo fresh aerosol particle size distribution, the vertical mass loading of stratospheric aerosol particles was estimated to vary between 0.037 and 0.047 g m22 from July 24 to 27 and to increase to values ranging between 0.048 and 0.074 g m22 during the rest of summer 1991, presenting a mean value of (0.063 6 0.009) g m22 for the two-month period. The measurements taken in summer 1992 show that parameter b ranged between 0.08 and 0.12, while parameter a was found to vary between 0.23 and 0.73. The stratospheric aerosol depth values were analysed through a best-fit procedure based on a linear combination of a background model of small aerosol particles and a trimodal model consisting of aged volcanic aerosol particles. Following this procedure, the vertical mass loading of Pinatubo aerosol particles was found to vary between 0.043 and 0.057 g m22 during summer 1992, the mean value being evaluated as equal to (0.047 6 0.004) g m22

    From the dual function lead AP2238 to AP2469, a multi-target-directed ligand for the treatment of Alzheimer\u2019s disease

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    The development of drugs with different pharmacological properties appears to be an innovative therapeutic approach for Alzheimer\u2019s disease. In this article, we describe a simple structural modification of AP2238, a first dual function lead, in particular the introduction of the catechol moiety performed in order to search for multi-target ligands. The new compound AP2469 retains antiacetylcholinesterase (AChE) and beta-site amyloid precursor protein cleaving enzyme (BACE)1 activities compared to the reference, and is also able to inhibit Ab42 self aggregation, Ab42 oligomer-binding to cell membrane and subsequently reactive oxygen species formation in both neuronal and microglial cells. The ability of AP2469 to interfere with Ab42 oligomer-binding to neuron and microglial cell membrane gives this molecule both neuroprotective and antiinflammatory properties. These findings, together with its strong chain-breaking antioxidant performance, make AP2469 a potential drug able to modify the course of the diseas

    Recurrent Scedosporium apiospermum mycetoma successfully treated by surgical excision and terbinafine treatment: a case report and review of the literature

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    Background: Scedosporium apiospermum is an emerging opportunistic filamentous fungus, which is notorious for its high levels of antifungal ‑resistance. It is able to cause localized cutaneous or subcutaneous infections in both immu‑ nocompromised and immunocompetent persons, pulmonary infections in patients with predisposing pulmonary diseases and invasive mycoses in immunocompromised patients. Subcutaneous infections caused by this fungus frequently show chronic mycetomatous manifestation. Case report: We report the case of a 70 ‑year ‑old immunocompromised man, who developed a fungal mycetoma‑ tous infection on his right leg. There was no history of trauma; the aetiological agent was identified by microscopic examination and ITS sequencing. This is the second reported case of S. apiospermum subcutaneous infections in Hungary, which was successfully treated by surgical excision and terbinafine treatment. After 7 months, the patient remained asymptomatic. Considering the antifungal susceptibility and increasing incidence of the fungus, Sce - dosporium related subcutaneous infections reported in the past quarter of century in European countries were also reviewed. Conclusions: Corticosteroid treatment represents a serious risk factor of S. apiospermum infections, especially if the patient get in touch with manure ‑enriched or polluted soil or water. Such infections have emerged several times in European countries in the past decades. The presented data suggest that besides the commonly applied voricona‑ zole, terbinafine may be an alternative for the therapy of mycetomatous Scedosporium infections

    EUCAARI ion spectrometer measurements at 12 European sites – analysis of new particle formation events

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    We present comprehensive results on continuous atmospheric cluster and particle measurements in the size range ~1–42 nm within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) project. We focused on characterizing the spatial and temporal variation of new particle formation events and relevant particle formation parameters across Europe. Different types of air ion and cluster mobility spectrometers were deployed at 12 field sites across Europe from March 2008 to May 2009. The measurements were conducted in a wide variety of environments, including coastal and continental locations as well as sites at different altitudes (both in the boundary layer and the free troposphere). New particle formation events were detected at all of the 12 field sites during the year-long measurement period. From the data, nucleation and growth rates of newly formed particles were determined for each environment. In a case of parallel ion and neutral cluster measurements, we could also estimate the relative contribution of ion-induced and neutral nucleation to the total particle formation. The formation rates of charged particles at 2 nm accounted for 1–30% of the corresponding total particle formation rates. As a significant new result, we found out that the total particle formation rate varied much more between the different sites than the formation rate of charged particles. This work presents, so far, the most comprehensive effort to experimentally characterize nucleation and growth of atmospheric molecular clusters and nanoparticles at ground-based observation sites on a continental scale

    Changing perceptions of hunger on a high nutrient density diet

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    <p>Abstract</p> <p>Background</p> <p>People overeat because their hunger directs them to consume more calories than they require. The purpose of this study was to analyze the changes in experience and perception of hunger before and after participants shifted from their previous usual diet to a high nutrient density diet.</p> <p>Methods</p> <p>This was a descriptive study conducted with 768 participants primarily living in the United States who had changed their dietary habits from a low micronutrient to a high micronutrient diet. Participants completed a survey rating various dimensions of hunger (physical symptoms, emotional symptoms, and location) when on their previous usual diet versus the high micronutrient density diet. Statistical analysis was conducted using non-parametric tests.</p> <p>Results</p> <p>Highly significant differences were found between the two diets in relation to all physical and emotional symptoms as well as the location of hunger. Hunger was not an unpleasant experience while on the high nutrient density diet, was well tolerated and occurred with less frequency even when meals were skipped. Nearly 80% of respondents reported that their experience of hunger had changed since starting the high nutrient density diet, with 51% reporting a dramatic or complete change in their experience of hunger.</p> <p>Conclusions</p> <p>A high micronutrient density diet mitigates the unpleasant aspects of the experience of hunger even though it is lower in calories. Hunger is one of the major impediments to successful weight loss. Our findings suggest that it is not simply the caloric content, but more importantly, the micronutrient density of a diet that influences the experience of hunger. It appears that a high nutrient density diet, after an initial phase of adjustment during which a person experiences "toxic hunger" due to withdrawal from pro-inflammatory foods, can result in a sustainable eating pattern that leads to weight loss and improved health. A high nutrient density diet provides benefits for long-term health as well as weight loss. Because our findings have important implications in the global effort to control rates of obesity and related chronic diseases, further studies are needed to confirm these preliminary results.</p

    Poverty and Wellbeing Impacts of Microfinance : What Do We Know?

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    Over the last 35 years, microfinance has been generally regarded as an effective policy tool in the fight against poverty. Yet, the question of whether access to credit leads to poverty reduction and improved wellbeing remains open. To address this question, we conduct a systematic review of the quantitative literature of microfinance’s impacts in the developing world, and develop a theory of change that links inputs to impacts on several welfare outcomes. Overall, we find that the limited comparability of outcomes and the heterogeneity of microfinance-lending technologies, together with a considerable variation in socio-economic conditions and contexts in which impact studies have been conducted, render the interpretation and generalization of findings intricate. Our results indicate that, at best, microfinance induces short-term dynamism in the financial life of the poor; however, we do not find compelling evidence that this dynamism leads to increases in income, consumption, human capital and assets, and, ultimately, a reduction in poverty

    Understanding Factors Associated With Psychomotor Subtypes of Delirium in Older Inpatients With Dementia

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    Paternal effects on early embryogenesis

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    Historically, less attention has been paid to paternal effects on early embryogenesis than maternal effects. However, it is now apparent that certain male factor infertility phenotypes are associated with increased DNA fragmentation and/or chromosome aneuploidies that may compromise early embryonic development. In addition, there is a growing body of evidence that the fertilizing sperm has more function than just carrying an intact, haploid genome. The paternally inherited centrosome is essential for normal fertilization, and the success of higher order chromatin packaging may impact embryogenesis. Epigenetic modifications of sperm chromatin may contribute to the reprogramming of the genome, and sperm delivered mRNA has also been hythesized to be necessary for embryogenesis. There is less information about the epigenetic factors affecting embryogenesis than genetic factors, but the epigenetics of gamete and early embryogenesis is a rapidly advancing field
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