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Anton Lamboj Oliver Lucanus Patrick Osei Darko J. Pablo Arroyo-Mora Margaret Kalacska 《Biotropica》2020,52(5):896-912
Remote sensing has become an integral and invaluable tool to inform biodiversity conservation and monitoring of habitat degradation and restoration over time. Despite the disproportionately high levels of biodiversity loss in freshwater ecosystems worldwide, ichthyofauna are commonly overlooked in favor of other keystone species. Freshwater fish, as indicators of overall aquatic ecosystem health, can also be indicators of larger scale problems within an ecosystem. As a case study with multi-temporal, multi-resolution satellite imagery, we examined deforestation and forest fragmentation around the Atewa Forest Reserve, Ghana. Within small creeks, Limbochromis robertsi, a unique freshwater cichlid with an extremely limited distribution range, can be found. Historically, the land cover in the area has undergone substantial deforestation for agriculture and artisanal small-scale mining. In the 1389-km2 study area, we found deforestation accelerated along with increased forest fragmentation in the 2014–2017 period (167.4 km2 of deforestation) with the majority of the forest loss along the river and creek banks due to small-scale mining operations and increased agriculture. Field visits indicated a decrease in the total L. robertsi population by approximately 90% from the early 1990s to 2018. Its distribution has been reduced to higher elevations by anthropogenic habitat barriers at low elevations and the presence of predatory species. Loss of riparian forest through land use and cover change to mining and agriculture contributes to the habitat degradation for this endemic species. Fine spatial- and temporal-scale studies are required to assess habitat characteristics are not captured by global- or continental-scale datasets. 相似文献
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Kristin L. Boswell Robert Paris Eli Boritz David Ambrozak Takuya Yamamoto Sam Darko Kaska Wloka Adam Wheatley Sandeep Narpala Adrian McDermott Mario Roederer Richard Haubrich Mark Connors Julie Ake Daniel C. Douek Jerome Kim Constantinos Petrovas Richard A. Koup 《PLoS pathogens》2014,10(1)
The interaction between follicular T helper cells (TFH) and B cells in the lymph nodes and spleen has a major impact on the development of antigen-specific B cell responses during infection or vaccination. Recent studies described a functional equivalent of these cells among circulating CD4 T cells, referred to as peripheral TFH cells. Here, we characterize the phenotype and in vitro B cell helper activity of peripheral TFH populations, as well as the effect of HIV infection on these populations. In co-culture experiments we confirmed CXCR5+ cells from HIV-uninfected donors provide help to B cells and more specifically, we identified a CCR7highCXCR5highCCR6highPD-1high CD4 T cell population that secretes IL-21 and enhances isotype-switched immunoglobulin production. This population is significantly decreased in treatment-naïve, HIV-infected individuals and can be recovered after anti-retroviral therapy. We found impaired immunoglobulin production in co-cultures from HIV-infected individuals and found no correlation between the frequency of peripheral TFH cells and memory B cells, or with neutralization activity in untreated HIV infection in our cohort. Furthermore, we found that within the peripheral TFH population, the expression level of TFH-associated genes more closely resembles a memory, non-TFH population, as opposed to a TFH population. Overall, our data identify a heterogeneous population of circulating CD4 T cells that provides in vitro help to B cells, and challenges the origin of these cells as memory TFH cells. 相似文献
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Pelcić G Aberle N Pelcić G Vlasić-Cicvarić I Kraguljac D Bencić I Coha AG Karacić S 《Collegium antropologicum》2012,36(2):543-548
The aim of research was to investigate: the need for health care information of Croatian adolescents aged from 13 to 18 years; the difference in evaluation of the frequency of receiving information between hospitalized and healthy children; if the hospitalized children expectations about the frequency of receiving health care information differed significantly from information they have actually received; whose information was most comprehensible to the hospitalized children (doctors, parents, other health care givers). The children were either hospitalized in the pediatrics departments or were high schools pupils (healthy children). The hospitalized children "Completely agreed" (92.7%) with the statement "When I am sick, I should receive information about my health" in comparison to the healthy children (85.1%). In comparison to healthy children, the hospitalized children assessed that doctors, other health care givers and parents should give them information more frequently. The experience of hospitalized children indicate that they received less information then they have actually excepted. The information received from doctors was mostly in correlation with the understanding of this information. We concluded that the children want to be informed about their health, especially hospitalized children. Health care professionals should offer understandable health care information according to the children's expectation. 相似文献
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Charlanne de Oliveira Marques Izabela Amaro Espindula Eric Kwame Karikari Darko Leandro Viosa Bonetti Anelise Sonza Wania Aparecida Partata Maria Cristina Faccioni-Heuser Taís Malysz 《Journal of musculoskeletal & neuronal interactions》2021,21(1):68
Objectives:Whole-body vibration (WBV) is commonly used to improve motor function, balance and functional performance, but its effects on the body are not fully understood. The main objective was to evaluate the morphometric and functional effects of WBV in an experimental nerve regeneration model.Methods:Wistar rats were submitted to unilateral sciatic nerve crush and treated with WBV (4-5 weeks), started at 3 or 10 days after injury. Functional performances were weekly assessed by sciatic functional index, horizontal ladder rung walking and narrow beam tests. Nerve histomorphometry analysis was assessed at the end of the protocol.Results:Injured groups, sedentary and WBV started at 3 days, had similar functional deficits. WBV, regardless of the start time, did not alter the histomorphometry parameters in the regeneration process.Conclusions:The earlier therapy did not change the expected and natural recovery after the nerve lesion, but when the WBV starts later it seems to impair function parameter of recovery. 相似文献
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Ionut V Liberty IF Hucking K Lottati M Stefanovski D Zheng D Bergman RN 《American journal of physiology. Endocrinology and metabolism》2006,291(4):E779-E785
The insulinotropic intestinal hormone GLP-1 is thought to exert one of its effects by direct action on the pancreatic beta-cell receptors. GLP-1 is rapidly degraded in plasma, such that only a small amount of the active form reaches the pancreas, making it questionable whether this amount is sufficient to produce a direct incretin effect. The aim of our study was to assess, in a dog model, the putative incretin action of GLP-1 acting directly on the beta-cell in the context of postprandial rises in GLP-1 and glucose. Conscious dogs were fed a high-fat, high-carbohydrate meal, and insulin response was measured. We also infused systemic glucose plus GLP-1, or glucose alone, to simulate the meal test values of these variables and measured insulin response. The results were as follows: during the meal, we measured a robust insulin response (52 +/- 9 to 136 +/- 14 pmol/l, P < 0.05 vs. basal) with increases in portal glucose and GLP-1 but only limited increases in systemic glucose (5.3 +/- 0.1 to 5.7 +/- 0.1 mmol/l, P = 0.1 vs. basal) and GLP-1 (6 +/- 0 to 9 +/- 1 pmol/l, P = 0.5 vs. basal). Exogenous infusion of systemic glucose and GLP-1 produced a moderate increase in insulin (43 +/- 5 to 84 +/- 15 pmol/l, 43% of the meal insulin). However, infusion of glucose alone, without GLP-1, produced a similar insulin response (37 +/- 6 to 82 +/- 14 pmol, 53% of the meal insulin, P = 0.7 vs. glucose and GLP-1 infusion). In conclusion, in dogs with postprandial rises in systemic glucose and GLP-1, the hormone might not have a direct insulinotropic effect and could regulate glycemia via indirect, portohepatic-initiated neural mechanisms. 相似文献
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Plain chest radiography plays a major role in the diagnosis and follow-up of pulmonary tuberculosis in childhood. The aim of our study was to investigate the distribution of characteristic chest radiographic findings at diagnosis in children with pulmonary tuberculosis. The age of the patients and the type and localization of radiographic changes at admission were retrospectively analyzed. We reviewed chest radiographs in 204 children admitted from January 1, 1991 until June 30, 1994 for newly diagnosed pulmonary tuberculosis. Mean age +/- SD was 6.4 +/- 4.2 years (range 0-14). The most common lesion was lymphadenopathy (found in 172 children, 84.3%). It was significantly more common in the youngest age group (0-4 years) and was more significantly present in the right hilo-mediastinal region. Parenchymal changes were found in 125 children (61.3%). They were also significantly more common in the young age group and in the right lung. Other less common lesions included pleuritis, atelectasis, destructive-cavitary lesions and miliary dissemination. In conclusion, the leading radiographic finding in pulmonary tuberculosis in childhood remains hilar lymphadenopathy, but parenchymal changes are clearly strongly present, and should be sought and appreciated in the diagnostic work-up for pulmonary tuberculosis in childhood. 相似文献
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Despite the high competition of synthetic fibers leather is nowadays still widely used for many applications. In order to ensure a sufficient stability of the skin matrix against many factors, such as microbial degradation, heat and sweat, a tanning process is indispensable. Using chromium (III) for this purpose offers a multitude of advantages, thus this way of tanning is widely applied. During the use of chromium tanned leather as clothing material as well as for decoration/covering purposes, chromium is extracted from the leather and may then cause nocuous effects to human skin, e.g. allergic reactions. Thus the knowledge of the total chromium content of leather samples expected to come into prolonged touch with human skin is very important. In car industry leather is used as cover for seats, steering wheel and gearshift lever The chromium contents often chromium tanned leather samples used in car industry were determined. First all samples were dried at 65 degrees C overnight and then cut in small pieces using a ceramic knife, weighed and analyzed by inductively coupled plasma--optical emission spectrometry (ICP-OES) after acidic microwave assisted digestion. The total chromium amounts found were in the range from 19 mg/g up to 32 mg/g. The extraction yield of chromium from leather samples in sweat is approximately 2-7%. Thus especially during long journeys in summer chromium can be extracted in amounts which may cause nocuous effects for example on the palm of the hands or on the back. 相似文献
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Branislav Ranković Darko Ranković Marijana Kosanić Danijela Marić 《Central European Journal of Biology》2010,5(5):649-655
The aim of this study was to characterize the antioxidant and antimicrobial activity of the methanol extracts of: Anaptychya ciliaris, Nephroma parile, Ochrolechia tartarea and Parmelia centrifuga. The methanol extract of the P. centrifuga showed a strong antioxidant activity, in comparison to the extracts from A. ciliaris, O. tartarea and N. parile which were relatively weaker. Furthermore, the methanol extract of the lichen P. centrifuga was shown to contain the highest total phenol content (54.19 mg/g of the dry extract). Interestingly, a statistically significant
positive relationship between the antioxidant activity and the total phenol content was observed. The minimum inhibitory concentration
(MIC) against six bacterial and eleven fungi was established for the methanol extracts from each of species of lichens. The
methanol extracts of the lichens P. centrifuga and O. tartarea showed the strongest both antibacterial and antifungal activity. Taken together, the results from this study suggest that
the lichens P. centrifuga and O. tartarea may be used as a natural source of antioxidants in addition to providing certain antimicrobial features. 相似文献
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Darko Kero Livia Cigic Ivana Medvedec Mikic Tea Galic Mladen Cubela Katarina Vukojevic 《Organogenesis》2016,12(3):152-167
Insulin-Like Growth Factor 2 (IGF-2) is a peptide hormone essential for prenatal growth and development. IGF-2 exerts its mitogenic effects via Insulin-Like Growth Factor 1 Receptor (IGF-1R), and is eliminated by binding to Insulin-Like Growth Receptor 2 (IGF-2R). IGF-2 is also negatively regulated by Phosphatase and Tensin Homolog (PTEN), a phosphatase mutated in various tumors. Not much is known about the interplay between these factors during human odontogenesis. In this study, expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN were analyzed by double immunofluorescence in incisor human tooth germs during the foetal period of development between the 7th and 20th gestational week. Throughout the investigated period, IGF-2 was mostly expressed in enamel organ, whereas mild to moderate expression of PTEN could be seen in dental papilla and parts of enamel organ. Expression of IGF-1R was ubiquitous and displayed strong intensity throughout the entire enamel organ. In contrast, expression of IGF-2R had rather erratic pattern in enamel organ and dental papilla alike. Expression patterns of IGF-2, IGF-1R, IGF-2R and PTEN in highly proliferative cervical loops, as well as in differentiating pre-ameloblasts and pre-odontoblasts of cusp tip region during the early and late bell stages when enamel organ acquires definitive shape, indicate importance of these factors in crown morphogenesis of human incisor. Taken together, our data suggest the involvement of IGF-2, IGF-1R, IGF-2R and PTEN in temporo-spatial patterning of basic cellular processes (proliferation, differentiation) during normal tooth development. They are also relevant for improving knowledge of molecular basis of human odontogenesis. 相似文献