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91.
The temporal expression of two cell surface proteins, called BEP1 and BEP4, during Paracentrosus lividus embryonic development was studied. These proteins are found in both monomeric and dimeric forms in egg and embryos and we have established that their specific form is related to their being in the cytoplasm or on the cell surface. The spatial distribution of BEP1 and BEP4 proteins in eggs and embryos was established by whole mount immunohistochemistry. These proteins are located in the animal part of unfertilized and fertilized eggs; thereafter they are much less represented in structures derived from the vegetal cells of the embryo such as the micromeres of the 16 cell stage, the primary mesenchyme of blastula and the gut of gastrula. At the prism stage BEP1 and BEP4 proteins are present to some ectodermal parts and thereafter, at the pluteus stage, to the oral region.  相似文献   
92.
We have isolated and characterized a cDNA clone corresponding to a new member of bep (butanol, extracted, proteins) Paracentrotus lividus multigene family coding for cell surface proteins. The cDNA, called bep3, encodes a 370 amino acid protein and shares the same structural organization in the coding region with other members of the same gene family already characterized. Expression of this clone studied by Northern blot and by whole mount hybridization shows that the bep3 messenger is transcribed during oogenesis and utilized till the gastrula stage, whereas at the prism stage, unlike other members of the same gene family, new synthesis of messenger occurs. By whole mount hybridization spatial distribution of bep3 messenger in egg and embryos is established. This messenger appears located in the animal half of the unfertilized egg and moves to the cortical zone after fertilization; it is not present in the structures derived by the vegetal part of the embryo, such as the micromeres of the 16-cell stage, the primary mesenchyme cells of the blastula, and the primary intestine of the gastrula. At the prism stage instead, hybridization of bep3 messenger is restricted to the part of the embryo that will give origin to the oral region as successively confirmed by hybridization at the pluteus stage. The result of whole mount hybridization was confirmed by Northern blot hybridization of separated meso-macromere and micromere RNAs. A Southern blot experiment demonstrates that bep3 is codified by a single copy gene. Conservation of the bep multigene family in several Mediterranean and Japanese sea urchin species has also been analyzed. © 1996 Wiley-Liss, Inc.  相似文献   
93.
Tidal hydroelectric power has been proposed as one potential solution for sustainable energy sources. The first tidal turbine in North America began continuous operation in the Annapolis River estuary (44 °45′N; 65° 29′W) in June, 1985. The machine is an axial‐flow, hydraulic‐lift propeller turbine, a type known to cause fish mortality. Anadromous populations of American shad Alosa sapidissima, striped bass Morone saxatilis and Atlantic sturgeon Acipenser oxyrinchus utilize the Annapolis River for spawning and other life history phases. After power generation commenced obvious turbine mortalities of these fishes began appearing downstream of the turbine. Assessments of the A. sapidissima adult spawning runs during 1981–1982 (pre‐operation) and 1989–1996 (operational) indicated significant changes in population characteristics after power generation began. Adult length, mass, age and per cent repeat spawners declined and total instantaneous mortality (Z) increased from 0.30 to 0.55. The pre‐turbine spawning runs had older fish with numerous adult cohorts whereas by 12 years after operation began runs consisted of younger fish with fewer adult cohorts. During 1972–1987 numerous studies indicated the Annapolis River had an important angling fishery for M. saxatilis, but detailed annual records kept by a fishing contest during 1983–1987 and an elite angler family during the period 1976–2008 demonstrated a rapid decline in the number of fish >4.0 kg after turbine operation began. Pre‐turbine catch by the angling family of fish >4.0 kg accounted for 84.1% of total catch, but declined significantly to 39.6% of total catch from 1986–1999, and to none from 2000–2008. The existence of an A. oxyrinchus stock in the Annapolis River was unknown before turbine operation, but during 1985–2017, 21 mortalities were recovered by chance seaward of the turbine. Mechanical strike and cavitation mortalities consisted of juveniles, mature males and gravid and spent females of ages 10 to 53 years found during June to October, the period when this anadromous species returns to its natal river to spawn. The results of the long‐term studies at Annapolis indicate managers should realize substantial risks exist for the fish resources of the world's oceans from deployment of instream propeller turbines.  相似文献   
94.
95.
Oxidative stress and dysfunctional mitochondria are among the earliest events in AD, triggering neurodegeneration. The use of natural antioxidants could be a neuroprotective strategy for blocking cell death. Here, the antioxidant action of ferulic acid (FA) on different paths leading to degeneration of recombinant β-amyloid peptide (rAβ42) treated cells was investigated. Further, to improve its delivery, a novel drug delivery system (DDS) was used. Solid lipid nanoparticles (SLNs), empty or containing ferulic acid (FA-SNL), were developed as DDS. The resulting particles had small colloidal size and highly negative surface charge in water. Using neuroblastoma cells and rAβ42 oligomers, it was demonstrated that free and SLNs-loaded FA recover cell viability. FA treatment, in particular if loaded into SLNs, decreased ROS generation, restored mitochondrial membrane potential (Δψm) and reduced cytochrome c release and intrinsic pathway apoptosis activation. Further, FA modulated the expression of Peroxiredoxin, an anti-oxidative protein, and attenuated phosphorylation of ERK1/2 activated by Aβ oligomers.  相似文献   
96.
Misfolded protein aggregation, including cataract, cause a significant amount of blindness worldwide. α-Crystallin is reported to bind misfolded proteins and prevent their aggregation. We hypothesize that supplementing retina and lens with α-crystallin may help to delay disease onset. The purpose of this study was to determine if αB-crystallin subunits containing a cell penetration peptide (gC-tagged αB-crystallin) facilitate the uptake of wild type αA-crystallin (WT-αA) in lens and retina. Recombinant human αB-crystallin was modified by the addition of a novel cell penetration peptide derived from the gC gene product of herpes simplex virus (gC-αB). Recombinant gC-αB and wild-type αA-crystallin (WT-αA) were purified from E. coli over-expression cultures. After Alexa-labeling of WT-αA, these proteins were mixed at ratios of 1:2, 1:5 and 1:10, respectively, and incubated at 37°C for 4 hours to allow for subunit exchange. Mixed oligomers were subsequently incubated with tissue culture cells or mouse organ cultures. Similarly, crystallin mixtures were injected into the vitreous of rat eyes. At various times after exposure, tissues were harvested and analyzed for protein uptake by confocal microscopy or flow cytometry. Chaperone-like activity assays were performed on α-crystallins ratios showing optimal uptake using chemically-induced or heat induced substrate aggregation assays. As determined by flow cytometry, a ratio of 1:5 for gC-αB to WT-αA was found to be optimal for uptake into retinal pigmented epithelial cells (ARPE-19). Chaperone-like activity assays demonstrated that hetero-oligomeric complex of gC-αB to WT-αA (in 1:5 ratio) retained protein aggregation protection. We observed a significant increase in protein uptake when optimized (gC-αB to WT-αA (1:5 ratio)) hetero-oligomers were used in mouse lens and retinal organ cultures. Increased levels of α-crystallin were found in lens and retina following intravitreal injection of homo- and hetero-oligomers in rats.  相似文献   
97.
K E Asin  L Bednarz  W Montana 《Life sciences》1990,46(25):1817-1823
Rats with unilateral, electrolytic substantia nigra (ESN) lesions were tested for rotation following systemic injections of the D1 dopamine receptor agonist SKF38393 or the D2 agonist quinpirole. Only quinpirole produced significant levels of rotation, which was ipsilateral in direction. This rotation was potentiated by coadministration of the D1 agonist, and was significantly reduced by injections of either a D1 or D2 receptor antagonist. Other groups of lesioned animals were treated with reserpine for 5 days and were then tested for rotation in response to the agonists. In this case, SKF38393 produced significant levels of contralateral rotation, while quinpirole-induced rotation remained ipsilateral; coadministration of the D1 and D2 agonists resulted in pronounced ipsilateral rotation. These results stress a role for D1 receptor mechanisms in producing rotation, and suggest that different striatal efferent pathways mediate rotation in response to selective agonists following ESN lesions.  相似文献   
98.
99.
MOTIVATION: Time course gene expression experiments are performed to study time-varying changes in mRNA levels of thousands of genes. Statistical methods from functional data analysis (FDA) have recently gained popularity for modelling and exploring such time courses. Each temporal profile is treated as the realization of a smooth function of time, or curve, and the inferred curve becomes the basic unit of statistical analysis. The task of identifying genes with differential temporal profiles then consists of detecting statistically significant differences between curves, where such differences are commonly quantified by computing the area between the curves or the l? distance. RESULTS: We propose a general test statistic for detecting differences between gene curves, which only depends on a suitably chosen distance measure between them. The test makes use of a distance-based variance decomposition and generalizes traditional MANOVA tests commonly used for vectorial observations. We also introduce the visual l? distance, which is shown to capture shape-related differences in gene curves and is robust against time shifts, which would otherwise inflate the traditional l? distance. Other shape-related distances, such as the curvature, may carry biological significance. We have assessed the comparative performance of the test on realistically simulated datasets and applied it to human immune cell responses to bacterial infection over time.  相似文献   
100.
Glutamate release by primary brain tumors induces epileptic activity   总被引:1,自引:0,他引:1  
Epileptic seizures are a common and poorly understood comorbidity for individuals with primary brain tumors. To investigate peritumoral seizure etiology, we implanted human-derived glioma cells into severe combined immunodeficient mice. Within 14-18 d, glioma-bearing mice developed spontaneous and recurring abnormal electroencephalogram events consistent with progressive epileptic activity. Acute brain slices from these mice showed marked glutamate release from the tumor mediated by the system x(c)(-) cystine-glutamate transporter (encoded by Slc7a11). Biophysical and optical recordings showed glutamatergic epileptiform hyperexcitability that spread into adjacent brain tissue. We inhibited glutamate release from the tumor and the ensuing hyperexcitability by sulfasalazine (SAS), a US Food and Drug Administration-approved drug that blocks system x(c)(-). We found that acute administration of SAS at concentrations equivalent to those used to treat Crohn's disease in humans reduced epileptic event frequency in tumor-bearing mice compared with untreated controls. SAS should be considered as an adjuvant treatment to ameliorate peritumoral seizures associated with glioma in humans.  相似文献   
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