排序方式: 共有75条查询结果,搜索用时 15 毫秒
31.
Understanding the effects of membrane fouling on system capacity is critical for the successful design and scale-up of microfiltration systems. The underlying morphology and structure of the microfiltration membrane can have a significant effect on system capacity by altering the rate and extent of fouling. Experimental data were obtained for system capacity during protein microfiltration using several model membranes with both homogeneous and composite structures. Data were compared with predictions of a new model that can account for both pore blockage and cake formation, and also includes the effects of membrane morphology on internal flow profiles within the membrane. Membranes with highly interconnected pores have a significantly higher capacity due to the reduction in flux decline arising from the fluid flow under and around any surface blockage. The model calculations are in good agreement with the flux decline data, allowing far more accurate predictions of system capacity than for the commonly used V(max) analysis. 相似文献
32.
Allogeneic hematopoietic stem cell transplantation is a deterministic curative procedure for various hematologic disorders and congenital immunodeficiency. Despite its increased use, the mortality rate for patients undergoing this proce dure remains high, mainly due to the perceived risk of exacerbating graft-versus-host disease (GVHD). However, even with immunosuppressive agents, some patients still develop GVHD. Advanced mesenchymal stem/stromal cell (MSC) strategies have been proposed to achieve better therapeutic outcomes, given their immunosuppressive potential. However, the efficacy and trial designs have varied among the studies, and some research findings appear contradictory due to the challenges in characterizing the in vivo effects of MSCs. This review aims to provide real insights into this clinical entity, emphasizing diagnostic, and therapeutic considerations and generating pathophysiology hypotheses to identify research avenues. The indications and timing for the clinical application of MSCs are still subject to debate. 相似文献
33.
Nucleosides VI: A Novel and Convenient Synthesis of Purine S-Cyclonucleosides Via Mitsunobu Reaction
Ji-Wang Chern Chia-Chi Kuo Ming-Jyh Chang Lee-Tai Liu 《Nucleosides, nucleotides & nucleic acids》2013,32(9):941-949
Abstract Two representative S-cyclonucleosides, 8,5′-anhydro-2′, 3′-O-isopropylidene-8-mercaptoadenosine (3) and 8,2′-anhydro-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-8-mercaptoguanosine (8), were prepared in good yields by dropwise addition of one equivalent each of triphenylphosphine and DEAD in DMF into a mixture of 2′,3′-O-isopropylidene-8-mercaptoadenosine (2) or 3′,5′-O-(tetra-iso-propyldisiloxane-1,3-diyl)-8-mercaptoguanosine (7), respectively, in DMF. Treatment of compound 2 with two equivalents each of triphenylphosphine and DEAD in DMF afforded N-[8,5′-anhydro-2′,3′-O-isopropylidene-8-mercaptopurin-6-yl]triphenylphospha-λ5-azene (4) in 87% yield. 相似文献
34.
35.
36.
37.
A β-1,3-glucanase gene, encoding a protein of 1,793 amino acids, was cloned from a strain of Paenibacillus sp. in this study. This large protein, designated as LamA, consists of many putative functional units, which include, from
N to C terminus, a leader peptide, three repeats of the S-layer homologous module, a catalytic module of glycoside hydrolase
family 16, four repeats of the carbohydrate-binding module of family CBM_4_9, and an analogue of coagulation factor Fa5/8C.
Several truncated proteins, composed of the catalytic module with various organizations of the appended modules, were successfully
expressed and characterized in this study. Data indicated that the catalytic module specifically hydrolyze β-1,3- and β-1,3–1,4-glucans.
Also, laminaritriose was the major product upon endolytic hydrolysis of laminarin. The CBM repeats and Fa5/8C analogue substantially
enhanced the hydrolyzing activity of the catalytic module, particularly toward insoluble complex substrates, suggesting their
modulating functions in the enzymatic activity of LamA. Carbohydrate-binding assay confirmed the binding capabilities of the
CBM repeats and Fa5/8C analogue to β-1,3-, β-1,3–1,4-, and even β-1,4-glucans. These appended modules also enhanced the inhibition
effect of the catalytic module on the growth of Candida albicans and Rhizoctonia solani. 相似文献
38.
Xuewei Zhu Soonkyu Chung Xin Bi Chia-Chi Chuang Amanda L. Brown Mingxia Liu Jeongmin Seo Helen Cuffe Abraham K. Gebre Elena Boudyguina John S. Parks 《Journal of lipid research》2013,54(10):2708-2717
Obesity-associated low-grade chronic inflammation plays an important role in the development of insulin resistance. The membrane lipid transporter ATP-binding cassette transporter A1 (ABCA1) promotes formation of nascent HDL particles. ABCA1 also dampens macrophage inflammation by reducing cellular membrane cholesterol and lipid raft content. We tested the hypothesis that myeloid-specific ABCA1 deletion may exacerbate insulin resistance by increasing the obesity-associated chronic low-grade inflammation. Myeloid cell-specific ABCA1 knockout (MSKO) and wild-type (WT) mice developed obesity, insulin resistance, mild hypercholesterolemia, and hepatic steatosis to a similar extent with a 45% high-fat (HF) diet feeding or after crossing into the ob/ob background. Resident peritoneal macrophages and stromal vascular cells from obese MSKO mice accumulated significantly more cholesterol. Relative to chow, HF diet markedly induced macrophage infiltration and inflammatory cytokine expression to a similar extent in adipose tissue of WT and MSKO mice. Among pro-inflammatory cytokines examined, only IL-6 was highly upregulated in MSKO-ob/ob versus ob/ob mouse peritoneal macrophages, indicating a nonsignificant effect of myeloid ABCA1 deficiency on obesity-associated chronic inflammation. In conclusion, myeloid-specific ABCA1 deficiency does not exacerbate obesity-associated low-grade chronic inflammation and has minimal impact on the pathogenesis of insulin resistance in both HF diet-induced and genetically obese mouse models. 相似文献
39.
40.
Cheng-Yi Chuang Ling-Yun Chen Ru-Huei Fu Shih-Ming Chen Ming-Hua Ho Jie-Mau Huang Chia-Chi Hsu Chien-Cheng Wang Meng-Shian Chen Rong-Tzong Tsai 《PloS one》2014,9(8)