共查询到19条相似文献，搜索用时 173 毫秒
1.
2.
3.
《科技风》2020,(27)
生物复合材料以其优异的可降解性和丰富的原料来源,正引起人们的广泛关注。本文研究了一种全纤维素复合材料的制备方法及其组成结构与力学性能之间的关系。这里首先利用乙酰化化学改性和超声物理分离相结合的方法制备得到了不同乙酰化程度的纳米纤维素作为力学增强填料,然后与塑化的醋酸纤维素母体通过热混方式制备出全醋酸纤维素复合材料。经研究发现,当乙酰化反应时间为5min时,纳米纤维素的乙酰化取代度为0.3左右,结晶度为68.5%,此时纳米纤维素在保证与醋酸纤维素母体有良好的界面相容性的同时又较好地保留了其晶体结构,因此制备得到的全纤维素复合材料的抗拉强度和杨氏模量分别可达到36.9MPa和2.9GPa,展示了广阔的市场应用前景。 相似文献
4.
对羟基苯甘氨酸是合成羟氨苄青霉素(阿莫西林)、头孢羟基苄(欧意)、头孢氯苯(先锋IV)等β-内酰胺类半合成抗生素的主要原料,在有机合成和药物生产中有着广泛的用途。而且,实际上合成这些新型的抗生素必不可少的侧链酸是D-对羟基苯甘氨酸。因此,在这些抗生素世界范围内的大量生产中,中间体D,L-对羟基苯甘氨酸的拆分起着决定性的作用。本文以乙酸丁酸纤维素为膜材料,制备乙酸丁酸纤维素手性固膜,并研究其对D,L-对羟基苯甘氨酸的手性拆分能力。研究显示:当CAB浓度为15%,DMF浓度为20%时,膜具有一定的拆分效果,D,L-对羟基苯甘氨酸对映体的分离因子可以达到1.9,说明膜分离技术有望成为大规模手性拆分非常有潜力的方法之一,具有良好的工业应用前景。 相似文献
5.
《大科技．科学之谜》2015,(5)
<正>大多数有关食欲的研究都集中在激素所扮演的角色上,但近几年,有人发现,即使老鼠的肠道内激素水平保持不变,它们也会食欲不振。最近一项研究或可解释为什么。研究人员发现,吃高脂肪食物的老鼠,若在它们的食物中添加植物纤维,体重就会增加得慢一些。他们用仪器跟踪老鼠体内一种叫"醋酸纤维素"的物质。醋酸纤维素是植物纤维被消化的时候,在肠道内生成的。传统上认为,当新陈代谢时,醋酸纤维素最多只能到达肝脏。但让研究人员吃惊的是,一些醋酸纤维素竟然 相似文献
6.
7.
8.
纤维素作为世界上最丰富的可再生资源,将纤维素功能化是人们研究的热点之一,文章综述了纤维素智能化的设计原理、纤维素智能材料的种类、智能化研究进展。 相似文献
9.
10.
11.
The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory.
An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation
electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose
acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of capillary
electrophoresis and cellulose acetate membrane electrophoresis were good (r=0.89∼0.97) for protein fractions and A/G ratio
except for β-gobulin fraction (r=0.60). Both within-run and day to day precisions (CVs) of assay results for 5 main fractions
and A/G ratio (n=10) were between 0.3∼6.3%. The reference ranges of serum protein fractions obtained from 200 healthy individuals
by cellulose acetate membrane electrophoresis were almost equal to that of capillary electrophoresis except for α-1 globulin
fraction. No significant difference of electropherograms between cellulose acetate electrophoresis and capillary electrophoresis
was observed in the abnormal serum such as presence of bilirubin (<20mg/dl), hemoglobin (<300 mg/dl), lipid (Intralipos <1%)
and samples from patients with acute phase response, liver injury, polyclonal hyper gammaglobulinemia or M-proteinemia. The
method of capillary immuno-fixation electrophoresis by subtraction showed good agreement with agarose gel immunofixation electrophoresis
by subtraction identifying 30 monoclonal gammmopathy patient samples. 相似文献
12.
对影响醋纤滤棒硬度的因素进行了试验分析:滤棒的硬度随丝束填充量、增塑剂施加量及丝束单丝旦数和总旦数的增加而增加;此外,滤棒的存放时间及存放环境对其硬度亦有不同程度的影响。 相似文献
13.
BackgroundButyrate is a histone deacetylase inhibitor that induces apoptosis and inhibits cell proliferation of colorectal cancer cells. To improve its anticancer activity, butyrate has been evaluated mixed with drugs and different molecules. Plant antimicrobial peptides are attractive anticancer alternative molecules because they show selective cytotoxic activity against different cancer cell lines. In this work, we explore if the plant defensin γ-thionin (Capsicum chinense) can improve butyrate activity on Caco-2 cell line and we also determined the mechanism of death activated.ResultsThe combined treatment of γ-thionin (3.5 µM) and butyrate (50 mM) showed higher cytotoxicity on Caco-2 cells with respect to single treatments. Also, the combined treatment reduced cell proliferation and exhibited a higher rate of apoptosis than single treatments. Combined treatment induced caspases 8 and 9 activation to an extent comparable with that of butyrate while γ-thionin did not activate caspases. Additionally, reactive oxygen species generation preceded the onset of apoptosis, and superoxide anion production was higher in cells treated with the combined treatment.ConclusionsThe γ-thionin from Habanero chili pepper improved the butyrate cytotoxicity on Caco-2 cells. This effect occurred through apoptosis induction associated with reactive oxygen species production. Therefore, the combination of butyrate with cytotoxic antimicrobial peptides could be an attractive strategy for cancer therapy.How to cite: Velázquez-Hernández ME, Ochoa-Zarzosa A, López-Meza JE, Defensin γ-thionin from Capsicum chinense improves butyrate cytotoxicity on human colon adenocarcinoma cell line Caco-2. Electron J Biotechnol 2021;52. https://doi.org/10.1016/j.ejbt.2021.04.009 相似文献
14.
A case of anti-trilodothyronine autoantibodies is presented in this report. The thyroid hormone profile of a hypertensive
patient, with multinodular goiter and history of exogenous thyroid hormone therapy, was found to be highly ambiguous. The
total as well as free T3 levels were consistently high (out of range) whereas the T4 (total and free) values were always within
normal limits. The thyrotropin was found to be partially suppressed. Very low T3-Uptake indicated some kind of interference
in the immunoassays. We incubated the sera with the radio-iodine labelled T3 and observed that the patient's serum bound about
ten times more radioactivity than a control run in parallel. On further resolving the serum proteins on cellulose acetate
electrophoresis, the radioactivity was detected in the γ-globulin band. Therefore it was established that the patient's serum
carried the antibodies reactive with T3 which were interfering in the immunoassays. Elevated anti-thyroid microsomal antibodies
were also present in the patient's serum. The anti-T3 antibodies were highly specific for T3 and did not show any cross reactivity
with the T4 or its analogues used in the estimation of free T4. 相似文献
15.
16.
17.
18.
19.
The thyroid hormone profile of a hypothyroid patient, with moderate sized diffuse goiter and history of exogenous thyroid
hormone therapy, was found to be highly ambiguous. The total as well as free T4 levels were consistently high (out of range)
with suppressed T3 (total and free) and elevated thyrotropin levels. We incubated the serum with the radio-iodine labelled
T4 and observed that the patient’s serum bound about 50.5% of the total radioactivity resulting in 85.3% interference in the
radioimmunoassay. On resolving the serum proteins by cellulose acetate electrophoresis, the radioactivity was detected in
the gamma globulin band. The protein profile showed mildly raised levels of IgG. Therefore it was established that the patient’s
serum carried T4 reactive antibodies (IgG) which were interfering in the immunoassays. Elevated anti-thyroid microsomal antibodies
were also present in the patient’s serum. The anti-T4 antibodies were highly specific for T4 and did not show any cross reactivity
with the T3 or its analogues used in the estimation of free T3. We stripped the serum by precipitating the immunoglobulins
and were successful in estimating the levels of free T4 in the stripped serum by single step radioimmunoassy. 相似文献