全文获取类型
收费全文 | 115篇 |
免费 | 9篇 |
国内免费 | 14篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1978年 | 1篇 |
排序方式: 共有138条查询结果,搜索用时 140 毫秒
11.
Dani?l B. van Schalkwijk Albert A. de Graaf Ben van Ommen Kees van Bochove Patrick C. N. Rensen Louis M. Havekes Niek C. A. van de Pas Huub C. J. Hoefsloot Jan van der Greef Andreas P. Freidig 《Journal of lipid research》2009,50(12):2398-2411
Increased plasma cholesterol is a known risk factor for cardiovascular disease. Lipoprotein particles transport both cholesterol and triglycerides through the blood. It is thought that the size distribution of these particles codetermines cardiovascular disease risk. New types of measurements can determine the concentration of many lipoprotein size-classes but exactly how each small class relates to disease risk is difficult to clear up. Because relating physiological process status to disease risk seems promising, we propose investigating how lipoprotein production, lipolysis, and uptake processes depend on particle size. To do this, we introduced a novel model framework (Particle Profiler) and evaluated its feasibility. The framework was tested using existing stable isotope flux data. The model framework implementation we present here reproduced the flux data and derived lipoprotein size pattern changes that corresponded to measured changes. It also sensitively indicated changes in lipoprotein metabolism between patient groups that are biologically plausible. Finally, the model was able to reproduce the cholesterol and triglyceride phenotype of known genetic diseases like familial hypercholesterolemia and familial hyperchylomicronemia. In the future, Particle Profiler can be applied for analyzing detailed lipoprotein size profile data and deriving rates of various lipolysis and uptake processes if an independent production estimate is given. 相似文献
12.
Rosa van den Berg Sander Kooijman Raymond Noordam Ashna Ramkisoensing Gustavo Abreu-Vieira Lauren L. Tambyrajah Wieneke Dijk Philip Ruppert Isabel M. Mol Barbara Kramar Rosanna Caputo Laura Sardón Puig Evelien M. de Ruiter Jan Kroon Menno Hoekstra Ronald J. van der Sluis Onno C. Meijer Ko Willems van Dijk Patrick C.N. Rensen 《Cell reports》2018,22(13):3521-3533
13.
Gautier T Tietge UJ Boverhof R Perton FG Le Guern N Masson D Rensen PC Havekes LM Lagrost L Kuipers F 《Journal of lipid research》2007,48(1):30-40
The impact of apolipoprotein C-I (apoC-I) deficiency on hepatic lipid metabolism was addressed in mice in the presence or the absence of cholesteryl ester transfer protein (CETP). In addition to the expected moderate reduction in plasma cholesterol levels, apoCIKO mice showed significant increases in the hepatic content of cholesteryl esters (+58%) and triglycerides (+118%) and in biliary cholesterol concentration (+35%) as compared with wild-type mice. In the presence of CETP, hepatic alterations resulting from apoC-I deficiency were enforced, with up to 58% and 302% increases in hepatic levels of cholesteryl esters and triglycerides in CETPTg/apoCIKO mice versus CETPTg mice, respectively. Biliary levels of cholesterol, phospholipids, and bile acids were increased by 88, 77, and 20%, respectively, whereas total cholesterol, HDL cholesterol, and triglyceride concentrations in plasma were further reduced in CETPTg/apoCIKO mice versus CETPTg mice. Finally, apoC-I deficiency was not associated with altered VLDL production rate. In line with the previously recognized inhibition of lipoprotein clearance by apoC-I, apoC-I deficiency led to decreased plasma lipid concentration, hepatic lipid accumulation, and increased biliary excretion of cholesterol. The effect was even greater when the alternate reverse cholesterol transport pathway via VLDL/LDL was boosted in the presence of CETP. 相似文献
14.
6种植物次生物质对斜纹夜蛾解毒酶活性的影响 总被引:2,自引:0,他引:2
草食性昆虫取食植物时遇到宿主植物中大量次生物质的化学防御,研究昆虫适应植物毒素的反防御策略具有重要的科学意义。分别添加0.01%肉桂酸、0.01%水杨酸、0.01%花椒毒素、0.02%槲皮素、0.05%黄酮和0.1%香豆素等6种植物次生物质的人工饲料饲养斜纹夜蛾(Spodoptera litura)五龄幼虫48 h后,测定斜纹夜蛾幼虫中肠和脂肪体中谷胱甘肽S-转移酶(GSTs)、羧酸酯酶(CarE)、P450的酶含量及头部乙酰胆碱酯酶(AChE)的活性,利用半定量RT-PCR检测中肠和脂肪体中CYP4M14和CYP4S9的基因表达水平。结果表明:取食肉桂酸和香豆素后,斜纹夜蛾中肠中CarE的酶活性分别提高了1.67和1.37倍,取食6种次生物质均能显著提高斜纹夜蛾脂肪体中GSTs酶活性。取食肉桂酸和香豆素48 h后,脂肪体中P450酶含量比对照增加2.93和14.50倍。取食肉桂酸、花椒毒素、槲皮素和香豆素后,斜纹夜蛾头部AchE酶活性与对照相比提高了1.53、1.80、2.36和1.56倍。6种次生物质均可诱导脂肪体中CYP4M14基因表达,槲皮素、肉桂酸和香豆素强烈诱导CYP4S9在脂肪体中表达。表明,斜纹夜蛾具有利用植物次生物质诱导其解毒酶的能力,进而提高其对毒素的抗性。 相似文献
15.
Chlorophyll fluorescence measurements have a wide range of applications from basic understanding of photosynthesis functioning
to plant environmental stress responses and direct assessments of plant health. The measured signal is the fluorescence intensity
(expressed in relative units) and the most meaningful data are derived from the time dependent increase in fluorescence intensity
achieved upon application of continuous bright light to a previously dark adapted sample. The fluorescence response changes
over time and is termed the Kautsky curve or chlorophyll fluorescence transient. Recently, Strasser and Strasser (1995) formulated
a group of fluorescence parameters, called the JIP-test, that quantify the stepwise flow of energy through Photosystem II,
using input data from the fluorescence transient. The purpose of this study was to establish relationships between the biochemical
reactions occurring in PS II and specific JIP-test parameters. This was approached using isolated systems that facilitated
the addition of modifying agents, a PS II electron transport inhibitor, an electron acceptor and an uncoupler, whose effects
on PS II activity are well documented in the literature. The alteration to PS II activity caused by each of these compounds
could then be monitored through the JIP-test parameters and compared and contrasted with the literature. The known alteration
in PS II activity of Chenopodium album atrazine resistant and sensitive biotypes was also used to gauge the effectiveness and sensitivity of the JIP-test. The information
gained from the in vitro study was successfully applied to an in situ study. This is the first in a series of four papers. It shows that the trapping parameters of the JIP-test were most affected
by illumination and that the reduction in trapping had a run-on effect to inhibit electron transport. When irradiance exposure
proceeded to photoinhibition, the electron transport probability parameter was greatly reduced and dissipation significantly
increased. These results illustrate the advantage of monitoring a number of fluorescence parameters over the use of just one,
which is often the case when the FV/FM ratio is used.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
Role of bicarbonate at the acceptor side of Photosystem II 总被引:1,自引:0,他引:1
van Rensen JJ 《Photosynthesis research》2002,73(1-3):185-192
Besides being the substrate for the carboxylation reaction of photosynthesis, CO2 (bicarbonate) is required for the activity of Photosystem II (water plastoquinone oxido-reductase). It plays a role on the
electron donor side as well as the electron acceptor side. In this contribution, attention will mostly be focused on the history
of research into the effects of bicarbonate on electron flow reactions on the acceptor side. Donor side reactions are discussed
in this issue by Alan Stemler.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Van Oosten M Rensen PC Van Amersfoort ES Van Eck M Van Dam AM Breve JJ Vogel T Panet A Van Berkel TJ Kuiper J 《The Journal of biological chemistry》2001,276(12):8820-8824
Septic shock is the most common cause of death in intensive care units and no effective treatment is available at present. Lipopolysaccharide (LPS) is the primary mediator of Gram-negative sepsis by inducing the production of macrophage-derived cytokines. Previously, we showed that apolipoprotein E (apoE), an established modulator of lipid metabolism, can bind LPS, thereby redirecting LPS from macrophages to hepatocytes in vivo. We now report that intravenously administered LPS strongly increases the serum levels of apoE. In addition, apoE can prevent the LPS-induced production of cytokines and subsequent death in rodents. Finally, apoE-deficient mice show a significantly higher sensitivity toward LPS than control wild-type mice. These findings indicate that apoE may have a physiological role in the protection against sepsis, and recombinant apoE may be used therapeutically to protect against LPS-induced endotoxemia. 相似文献
18.
Rensen PC Sliedregt LA Ferns M Kieviet E van Rossenberg SM van Leeuwen SH van Berkel TJ Biessen EA 《The Journal of biological chemistry》2001,276(40):37577-37584
The asialoglycoprotein receptor (ASGPr) on hepatocytes plays a role in the clearance of desialylated proteins from the serum. Although its sugar preference (N-acetylgalactosamine (GalNAc) > galactose) and the effects of ligand valency (tetraantennary > triantennary > diantennary > monoantennary) and sugar spacing (20 A 10 A 4 A) are well documented, the effect of particle size on recognition and uptake of ligands by the receptor is poorly defined. In the present study, we assessed the maximum ligand size that still allows effective processing by the ASGPr of mouse hepatocytes in vivo and in vitro. Here too, we synthesized a novel glycolipid, which possesses a highly hydrophobic steroid moiety for stable incorporation into liposomes, and a triantennary GalNAc(3)-terminated cluster glycoside with a high nanomolar affinity (2 nm) for the ASGPr. Incorporation of the glycolipid into small (30 nm) [(3)H]cholesteryl oleate-labeled long circulating liposomes (1-50%, w/w) caused a concentration-dependent increase in particle clearance that was liver-specific (reaching 85 +/- 7% of the injected dose at 30 min after injection) and mediated by the ASGPr on hepatocytes, as shown by competition studies with asialoorosomucoid in vivo. By using glycolipid-laden liposomes of various sizes between 30 and 90 nm, it was demonstrated that particles with a diameter of >70 nm could no longer be recognized and processed by the ASGPr in vivo. This threshold size for effective uptake was not related to the physical barrier raised by the fenestrated sinusoidal endothelium, which shields hepatocytes from the circulation, because similar results were obtained by studying the uptake of liposomes on isolated mouse hepatocytes in vitro. From these data we conclude that in addition to the species, valency, and orientation of sugar residues, size is also an important determinant for effective recognition and processing of substrates by the ASGPr. Therefore, these data have important implications for the design of ASGPr-specific carriers that are aimed at hepatocyte-directed delivery of drugs and genes. 相似文献
19.
Reevaluation of the role of bicarbonate and formate in the regulation of photosynthetic electron flow in broken chloroplasts 总被引:2,自引:1,他引:1 下载免费PDF全文
The stimulation of the Hill reaction in CO2-depleted broken chloroplasts (Pisum sativum L. cv Rondo) by the total amount of dissolved CO2 and HCO3− (bicarbonate*) was measured at several formate concentrations. Formate appears to be a competitive inhibitor of the bicarbonate* stimulation of electron flow. From these experiments we have obtained a reactivation constant (Kr) of 78 ± 31 micromolar NaHCO3 and an inhibition constant (Ki) of 2.0 ± 0.7 millimolar HCOONa at pH 6.5. In the absence of formate, significant electron flow was measured at a bicarbonate* concentration well below Kr, suggesting that electron flow from Q, the primary electron acceptor of photosystem II, to plastoquinone can proceed when no bicarbonate* is bound to the regulatory site at the QB-protein. If so, bicarbonate* stimulation of electron flow is mainly a diminution of the inhibition of electron flow by formate. In view of the results, it is proposed that regulation of linear electron flow by bicarbonate* and formate is a mechanism that could link cell metabolism to photosynthetic electron flow. 相似文献
20.
The role and mode of action of apolipoproteins CIII and AV: synergistic actors in triglyceride metabolism? 总被引:8,自引:0,他引:8
PURPOSE OF REVIEW: Apolipoprotein (apo)CIII and apoAV play an important role in triglyceride metabolism as evidenced by the unambiguous and opposing phenotypes of transgenic and knockout mouse models. In this review we discuss studies on the genetics, protein structure, and regulation of apoCIII and apoAV and compare their potential molecular mechanisms of action in triglyceride metabolism. We examine the hypothesis that apoCIII and apoAV synergistically affect triglyceride metabolism. RECENT FINDINGS: It has now been firmly established that variation in plasma triglyceride levels in a wide range of human populations is strongly associated with genetic variation at the chromosomal locus encoding both the APOC3 and APOA5 genes, the APOA1/C3/A4/A5 gene cluster. The close physical linkage of these genes and the frequent concurrence of genetic variants, however, complicate the assignment of specific metabolic defects to specific polymorphisms. Recent insight into the regulation of APOC3 and APOA5 gene expression and structural modeling studies on the apoAV protein have provided novel clues for the potential molecular mechanisms responsible for the effects of apoCIII and apoAV on triglyceride metabolism. SUMMARY: Hypertriglyceridemia is a major independent risk factor in the development of cardiovascular disease. Moreover, triglyceride-derived fatty acids are thought to play a key role in the development and progression of the metabolic syndrome. As modulators of triglyceride metabolism, apoCIII and apoAV are key players and potential therapeutic targets. However, little is known of their molecular mechanism and potential cooperativity. Rational therapeutic application will require the filling of this hiatus in our knowledge. 相似文献