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51.
Biological Trace Element Research - Cerium(IV) oxide is widely used as a catalyst in all aspects of human life and human beings are exposed to these materials. The purpose of this experimental...  相似文献   
52.
Mycopathologia - The coronavirus disease 2019 (COVID-19) pandemic emerged in Wuhan, China, in late 2109, and has rapidly spread around the world. Until May 25, 2020, there were 133,521 confirmed...  相似文献   
53.
Podocytes, highly specified kidney epithelial cells, live under several pathological stimuli and stresses during which they adapt themselves to keep homeostasis. Nevertheless, under extreme stress, a complex scenario of podocyte damage and its consequences occur. Podocyte damage causes foot process effacement and their detachment from the glomerular basement membrane, leading to proteinuria. Podocyte-derived extracellular vesicles (pEVs), mainly microparticles and exosomes are considered as signaling mediators of intercellular communication. Recently, it has been shown that throughout the injury-related migration procedure, podocytes are capable of releasing the injury-related migrasomes. Evidence indicates that at the early stages of glomerular disorders, increased levels of pEVs are observed in urine. At the early stage of nephropathy, pEVs especially migrasomes seem to be more sensitive and reliable indicators of podocyte stress and/or damage than proteinuria. This review highlights the current knowledge of pEVs and their values for the diagnosis of different kidney diseases.  相似文献   
54.
International Journal of Peptide Research and Therapeutics - One major issue in cancer immunotherapy is the large size of mAbs (150 kDa) which usually causes limitation in tumor...  相似文献   
55.
Nocardiosis is an acute or chronic infectious disease caused by the soil-borne filamentous bacteria belonging to the genus Nocardia. The organisms opportunistically infect both immunocompromised and immunocompetent individuals. The lungs are the primary site of infection and brain abscess is, by far, the most common complication following nocardial metastasis from pulmonary lesions. Although surgical intervention must always be considered in the treatment of nocardial brain abscess, it can obviously be cured by antibiotic therapy alone. This report describes a case infected by Nocardia cyriacigeorgica. Identification of the infectious agent was achieved by conventional and semi-nested PCR techniques. A 55-year-old woman with fever was referred to the infect disclinic of Imam Khomeini hospital in Tehran and was hospitalized after clinical assessment. She was a kidney transplant recipient for 4 years and was taking immunosuppressive treatment including azathioprine and methylprednisolone. Follow-up of the patient by CT scan revealed pulmonary infection and cerebral lesions. Specimens of the brain lesions contained filamentous bacteria. The patient received a combination of co-trimoxazole and ceftriaxone and brain abscesses as well as lung inflammation disappeared gradually during the course of antibiotic therapy within 3 months. The patient was discharged from the hospital after 2 months of therapy.  相似文献   
56.
Simulating signal transduction in cellular signaling networks provides predictions of network dynamics by quantifying the changes in concentration and activity-level of the individual proteins. Since numerical values of kinetic parameters might be difficult to obtain, it is imperative to develop non-parametric approaches that combine the connectivity of a network with the response of individual proteins to signals which travel through the network. The activity levels of signaling proteins computed through existing non-parametric modeling tools do not show significant correlations with the observed values in experimental results. In this work we developed a non-parametric computational framework to describe the profile of the evolving process and the time course of the proportion of active form of molecules in the signal transduction networks. The model is also capable of incorporating perturbations. The model was validated on four signaling networks showing that it can effectively uncover the activity levels and trends of response during signal transduction process.  相似文献   
57.
Stem cell therapy for degenerative diseases has been established; however there are controversies over the treatment of solid tumors with stem cell transplantation. In the present study, the anti-tumor action of mesenchymal stem cells (MSCs) has been examined in a mouse model of breast cancer with emphasize on tumor growth, angiogenesis and c-Myc expression in breast tumors. For this purpose, MSCs were isolated from bone marrow of Balb/c mice and characterized. A Balb/c mouse model of breast cancer was developed and subjected to cell therapy intra venous (I.V) or intra tumor (I.T) with MSCs. Tumor growth was measured using a digital caliber for until the end of experiment (30 days). Then the mice were sacrificed and their tumors were removed and processed for histopathological examination, immunohistochemical assay of CD31 and measuring of c-Myc expression using quantitative PCR. Detection of the labeled-MSCs in tumors following injection of the cells (I.V or I.T) clearly showed the homing of MSCs into tumors. Tumor growth in case of MSC-treated mice by I.V and I.T routes was inhibited by approximately 28% and 34% respectively compared to controls. The suppression of angiogenesis was reflected in Micro Vessel Density (MVD) following I.V or I.T delivery of the MSCs. c-Myc gene expression in tumor tissues of mice treated I.V or IT with MSCs was down-regulated to 28.0% and 16.0% respectively compare to control groups. In conclusion, growth inhibition of breast tumors in mice due to MSC therapy is associated with modulation of c-Myc activation and angiogenesis markers.  相似文献   
58.
Nassiri  M.  Elgersma  A. 《Plant and Soil》2002,246(1):107-121
The effects of applied nitrogen (N) on dynamics of regrowth, dry matter (DM) allocation and leaf characteristics of grass and clover were investigated. Binary mixtures and monocultures of the diploid perennial ryegrass cultivars Barlet (erect) and Heraut (prostrate) and the white clovers cvs. Alice (large-leaved) and Gwenda (small-leaved) were established in a field experiment. Grass monocultures received three levels of N application (0, 140 or 280 kg N ha–1), and mixtures 150 kg N ha–1 (+N) or no N (–N). N was applied split over the season. Application of N reduced the average clover content in the DM of the mixtures from 43 to 12%. Due to defoliation, clover lost relatively more leaf area and less DM than grass, leading to a lower clover fraction in the leaf area index (LAI) of the stubble at the start of the next regrowth. In the –N mixtures, the clover fraction of the biomass and of the LAI increased within successive regrowth periods. In the +N mixtures, large-leaved Alice maintained its content during summer, mainly due to its greater petiole length which increased in response to N. The opposite was observed for Gwenda. At each harvest, the content of small-leaved Gwenda in the LAI and DM was lower than in the stubble at the start of regrowth. The allocation of DM to the petioles of Alice led to a decrease in the leaf weight ratio (LWR) in the +N mixtures, while Gwenda had a higher LWR and specific leaf area (SLA) in the +N mixtures than in the –N mixtures. There was little or no effect of ryegrass cultivar on competition with white clover.  相似文献   
59.
Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols.  相似文献   
60.
Elgersma  A.  Schlepers  H.  Nassiri  M. 《Plant and Soil》2000,221(2):281-299
Nitrogen (N) fertiliser and clover cultivar choice affect competition and productivity in grass-clover mixtures. Pure stands and mixtures of perennial ryegrass and white clover cultivars with contrasting growth habits were examined. The aim of this work was to study the effect of repetitive nitrogen (N) application and cultivar combination on competition and productivity, N yield in the harvested herbage, N2 fixation in mixtures and pure stands, and transfer of N from clover to the companion grass. Large-leaved white clover cultivar Alice and small-leaved cv. Gwenda and perennial ryegrass cvs. Barlet (erect) and Heraut (prostrate) were sown in pure stands and as four binary grass-clover mixtures on a sandy soil in 1995. In the mixtures, two levels of N fertiliser were applied: 0 (-N) and 150 and 180 kg ha-1 y-1 N (+N) in 1996 and 1997, respectively, while the grass monocultures received three N levels (0, 140/180 and 280/360 kg ha-1) in 1996 and 1997, respectively. No N was applied to pure clover. The plots were cut five times during 1996 and six times during 1997. Fertiliser N was applied in early spring and after every harvest. The treatments were continued until the summer of 1999. In pure grass, the applied N was effectively recovered. In mixtures, N application affected competition by enhancing grass growth and the overall effect of N application was 17 kg DM per kg N applied in 1996. However, there was no yield response to N fertilizer in 1997, because this was compensated for by a higher clover production in unfertilised mixtures. In 1997, -N mixtures yielded more N than +N mixtures, owing to the higher clover content and N2 fixation. Large-leaved clover cv. Alice was better able to withstand the negative effect of repetitive N application on clover production in mixtures and increased its proportion during the growing season of the second harvest year. In 1997, mixtures with Alice yielded more N than mixtures with Gwenda, but in pure clover swards, there was no cultivar effect on N yield. Also, during the autumn of 1998 and the spring of 1999, the clover content was highest in mixtures with Alice. Harvested N and apparent N2 fixation were almost twice as high in 1997 as in 1996. N yield and apparent N2 fixation were higher in pure clover than in mixtures. In mixtures, the apparent N2 fixation in 1996 was 142 kg N ha-1, irrespective of cultivar or N treatment. In 1997, it was on average 337 kg N ha-1, and higher in -N mixtures and in mixtures with Alice. For each tonne of clover DM in the harvested herbage, 65 and 57 kg N was harvested in 1996 and 1997 in -N mixtures, respectively. The apparent transfer of clover-derived N to grass was on average 29 and 70 kg N ha-1 yr-1 in 1996 and 1997, respectively. It was highest in +N mixtures and highest in mixtures with Gwenda in 1997. In contrast to clover, the grass cultivars were very similar in their productivity and seasonal patterns, despite their contrasting growth habits. Seasonal trends in N yield, N transfer and N recovery are discussed in relation to fertilizer application regimes and variation in production patterns in mixtures and pure stands. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
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