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1.
研究了用三偏磷酸钠为交联剂制备高交联玉米淀粉的方法,采用偏光显微镜和广角X-射线衍射对交联玉米淀粉由多晶态向非晶态的渐变过程进行了详细报道,发现了随着温度的升高交联玉米淀粉逐渐非晶化现象,提出在高温条件下交联玉米淀粉存在着只含无定型结构的非晶颗粒态,并用扫描电镜对非晶颗粒态玉米淀粉的结构进行了详细研究.  相似文献   

2.
以三氯氧磷为交联剂制备非糊化的高交联木薯淀粉,并测定了反应的取代度和布拉班德粘度曲线,研究了在沸水中受热后非糊化淀粉的颗粒形貌及粒度分布等特性.提出高交联非糊化木薯淀粉存在着不同于原淀粉颗粒的在沸水中只发生轻度有限溶胀的非糊化颗粒态  相似文献   

3.
研究了以三氯氧磷为交联剂的高交联玉米淀粉的制备方法,报道了高交联玉米淀粉颗粒随反应取代度增加而逐渐非晶化的现象.采用偏光显微镜和广角X-射线衍射对其由多晶态向非晶态的渐变过程进行了研究,提出高交联玉米淀粉中存在不同于原淀粉多晶颗粒态的只含无定形结构的非晶颗粒态。对非晶颗粒态高交联玉米淀粉颗粒的粒度分布的进一步研究结果还表明,此时的淀粉颗粒发生了轻度的膨胀。  相似文献   

4.
报道了水分散体系高温溶胀、常温碱分散体系强碱溶胀作用非晶颗粒态马铃薯淀粉的制备方法 ,采用偏光显微镜对多晶态向非晶态的变化进行了确认 ,提出在一定条件下 ,高交联马铃薯淀粉 ,可以由原淀粉多晶颗粒态制备成只含无定形结构的非晶颗粒态淀粉  相似文献   

5.
本文研究了醚化和交联反应对玉米淀粉物理性质和结构的影响。实验结果表明:醚化明显地改善了淀粉糊的透明度和低温稳定性,降低了糊化温度;醚化淀粉再经交联后,可改善淀粉糊的粘度稳定性。醚化及交联反应主要在淀粉的非结晶区进行,反应并未破坏淀粉颗粒。醚化影响直链淀粉的构象并在颗粒表面形成空穴,交联则使淀粉颗粒在蒸煮后仍保持完整并抑制了直链淀粉的渗出。  相似文献   

6.
由三氯氧磷变性木薯淀粉所得的酯化交联淀粉,颗粒完整,形貌和偏光十字形态保持不变,反应主要发生在淀粉颗粒的无定形区内;经红外光谱等检测,发现产物分子中存在P—O—C和P=O基团,表明淀粉分子中的羟基置换出三氯氧磷分子中的氯原子而发生酯化和交联;极小取代度的变性淀粉,其碘复合物的可见光吸收光谱与原淀粉相似,三氯氧磷最先和支淀粉作用.  相似文献   

7.
用过氧化氢氧化淀粉,控制一定的氧化深度,进一步与交联剂反应合成了一种新型上浆剂.分析了过氧化氢的用量、反应pH值对氧化深度的影响,选择了一种新型交联剂进行交联反应.测试结果表明,该氧化交联淀粉上浆性能优良。  相似文献   

8.
研究了小麦淀粉与丙烯酰胺的接枝共聚物的物理特性和结构特征,实验结果表明:该接枝共聚物在热性质上与原淀粉有明显的区别,其糊化温度比原淀粉略低,粘度热稳定性及溶解度较原淀粉均有提高。接枝共聚反应不仅发生在淀粉颗粒的表面上,而且也发生在颗粒结构的内部,但反应仅发生在淀粉的无定型区。  相似文献   

9.
用磷酸二氢钠作酯化剂在尿素存在下对甘薯淀粉进行酯化,通过正交试验确定制备具有冻融稳定性的甘著淀粉磷酸单酯的最佳反应条件,研究了该酯化淀粉的理化性质和结构特征,结果表明:甘薯淀粉的最佳酯化条件是11.3%、NaH_2PO_4·2H_2O,4%尿素,160℃,2小时。酯化淀粉的溶解度、膨润力、糊透明度和粘度都增大,糊化温度降低,冻融稳定性明显增强。酯化反应不仅在颗粒表面,而且在内部也有发生。  相似文献   

10.
本文研究了交联一酯化复合变性淀粉——乙酰化二淀粉磷酸酯的结构和物理化学特性。结果表明:由于乙酰基取代了淀粉分子的部分羟基而使淀粉与碘的结合能力下降,展现为直链淀粉含量降低,淀粉的溶解度和膨润力增加;淀粉糊的透明度和冻融稳定性有所改善,交联反应还提高了淀粉的耐热、耐酸稳定性。  相似文献   

11.
M. Zubair  M. Ahmad  H. Jamil 《Andrologia》2015,47(7):744-750
The hypo‐osmotic swelling test (HOST) is widely used as a valuable test for determining sperm quality by evaluating the membrane integrity of spermatozoa of various domestic animals including cattle, horses and swine. The HOST has also been used as an indicator of the fertilising capacity of spermatozoa. This test is based on the swelling ability when functional spermatozoa submitted to hypo‐osmotic solutions. This test is commonly used as an important parameter for the evaluation of semen due to its strong correlation with semen evaluation parameters. The objective of this review was to analyse its significance in semen evaluation, swelling of spermatozoa under various osmolarities and variations in swelling percentage under different seasons.  相似文献   

12.
The hypoosmotic swelling test is a simple test for measuring the functional competence of the human sperm membrane. Fifty-four patients with idiopathic infertility were assessed by hypoosmotic swelling test and the results were compared with those of routine semen analysis and zona-free hamster ovum human sperm penetration test (ZSPT). Semen samples with abnormal semen parameters had lower percentage of swollen sperm in comparison with those with normal semen parameters. A positive correlation was observed between sperm concentration and sperm swelling (r = .50, p less than .05). A strong positive correlation was observed between the percentage of sperm motility and the percentage of swollen sperm (r = 0.60, p less than .01), and between motile sperm concentration and sperm swelling (r = .62, p less than .01). On the other hand, sperm swelling correlated only weakly with the percentage of sperm penetration. The results indicate that the hypoosmotic swelling test appears to evaluate different functional qualities of sperm than ZSPT.  相似文献   

13.
本研究用人精子低渗肿胀试验(HOS-test)分析了12例正常育龄男子的精液标本。精子分别用常规洗涤法、上游法和加入钙离子载体(A23187)诱导获能等三种不同方法处理后,分别在液化后、上游1h后、获能3h、6h、24h后测定精子的低渗肿胀率,结果显示经不同方法处理、在不同获能时相之后的精子,在24h之内其肿胀率保持在87.8±14.6%~73.3±11.9%之间,统计学分析表明各标本组肿胀率之间无明显差异。本研究提示在24h内精子膜的完整性不受获能时相及不同处理方法的影响。  相似文献   

14.
目的:结合在局麻吸脂术使用布比卡因的经验探讨肿胀液中布比卡因的安全使用、组成及其有效性。方法:选择2013年6月-2019年2月135例不同部位进行局麻负压吸脂的患者为研究对象,肿胀液主要成分为布比卡因和利多卡因,评估应用含布比卡因和利多卡因肿胀液在吸脂术中的药物组成、用量、疗效和安全性。结果:局麻吸脂中含布比卡因结合利多卡因的肿胀液适合于吸脂量低于4800ml的患者,仅含布比卡因一种麻醉药物的肿胀液在吸脂量为3600ml,布比卡因总用量为252mg(文献值为150mg)时未显示毒性;含布比卡因肿胀液组镇痛效果好于利多卡因组,术中起效快,术后1~4d无痛苦、恢复快、愈合好、并发症少、住院时间缩短一半。结论:布比卡因及布比卡因结合利多卡因的肿胀液在局麻吸脂中具有镇痛效果好、手术安全等优点,为其进一步应用提供了宝贵经验。证明布比卡因、尤其是布比卡因结合利多卡因作为肿胀液的麻醉药物值得进一步推广。  相似文献   

15.
A S Younger  P Curran  M M McQueen 《Injury》1990,21(3):179-181
Plaster-of-Paris backslabs are presently used after closed or operative reduction of fractures as they are thought to accommodate any swelling which may occur. This study was designed to examine the ability of different types of cast to expand with increasing internal pressure. The results of the study show clearly that a split and spread cast is the only safe cast to use after fracture as it allows for swelling. Backslabs are no better than a complete plaster at accommodating increased internal pressure. It is therefore recommended that backslabs are no longer used to maintain reductions when swelling is anticipated.  相似文献   

16.
OBJECTIVE:: Melkersson-Rosenthal Syndrome (MRS) is a rare granulomatous disease characterized by a triad, including orofacial swelling, facial palsy and lingua plicata with usually recurrent or progressive course. Orofacial swelling, the most often sign of MRS, leads to the both esthetic and functional deformities. Because of its unknown etiology, a rational treatment is difficult and management of MRS still remains symptomatic, aiming at to remove orofacial swelling mainly. Although the many nonsurgical therapies have been mentioned in the literature, none has been proved uniformly and predictably successful to date.In this paper, we present different surgical procedures and their outcomes in a series of 4 cases with MRS. The procedures including mucosa, submucosa and tangential muscle resection, crescent shaped commissuroplasty, and facial liposuction may be considered in surgical armamentarium when orofacial swelling becomes persistent. We think that the plastic surgeons may act more effectively in the management of the syndrome in the future.  相似文献   

17.
The hypo-osmotic swelling (HOS) test has been proposed as a useful assay for evaluation of the functional competence of the human sperm membranes. To assess this further, the HOS-test was evaluated in 187 semen samples collected from fertile men and from male patients consulting for infertility. These samples were classified as normal, oligo-, astheno- or oligoasthenozoospermic on the basis of their standard semen variables. The percentage of total sperm tail swelling and of sperm exhibiting different tail swelling patterns was recorded. In the fertile men and in the group of patients with normal semen variables, significantly more (P less than 0.001) HOS-reactive sperm were observed after hypo-osmotic treatment in comparison with those groups exhibiting abnormal semen parameters. Swelling of the sperm in a hypo-osmotic medium was highly correlated with both progressive motility (r = 0.62, P less than 0.001) and sperm viability (r = 0.65, P less than 0.001). A weak positive correlation was also observed between sperm swelling and sperm morphological features (r = 0.31, P less than 0.005) and between sperm swelling and sperm concentration (r = 0.31, P less than 0.005). No significant correlation was observed between sperm swelling and in-vitro sperm fertilizing capacity as assessed by the zona-free hamster oocyte penetration assay. However the majority of the semen samples (87.3%) showing a normal penetration rate (greater than or equal to 10%) also exhibited a 60% (or higher) reaction in the HOS-test.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
《Surgery (Oxford)》2022,40(7):420-431
There are many different causes of leg and foot swelling, some are benign and transient, others can be debilitating and progressive. Correct diagnosis and early treatment is crucial as conservative measures are most effective before the condition is allowed to progress. Current waiting times in the UK National Health Service (NHS) after the Covid-19 pandemic are leading to delays in care for people with chronic leg swelling. Delayed or inadequate treatment for these patients can lead to irreversible tissue damage, an episode of cellulitis, and progression to leg ulceration. There is in addition a significant impact on quality of life associated with living with the pain, anxiety, and reduced mobility. The causes of acute and chronic leg and foot swelling are outlined. Diagnosis and treatment of the common causes of leg and foot swelling in the Western adult population are discussed. The mainstay of treatment for most of these conditions relies on physical therapy and graduated elastic compression garments or elastic Velcro wraps as many do not have a cure.  相似文献   

19.
The hypo-osmotic sperm swelling (HOSS) test was performed on semen samples of five normospermic men from couples with prolonged infertility. Previously, the men had negative results of the zona-free hamster oocyte (ZFHO) test on two different ejaculates and the wives subsequently had become pregnant by donor insemination. A high swelling percentage (at least 60%) was found in all five men. It would appear that the HOSS test does not assess fertilizing capacity.  相似文献   

20.
Interface stresses and stump shape were measured during sessions over a two-month interval on a trans-tibial amputee subject. Results from thirteen transducer sites monitored during four sessions showed greater interface pressure changes over time at anterior sites than at lateral or posterior locations. There was a trend of decreased pressure with stump swelling and increased pressure for stump atrophy. During one session in which stump shape was monitored over a 23.1 min interval after ambulation, stump swelling was localised. Swelling tended to increase in the regions of initial enlargement, as opposed to redistributing through different areas over time. Regions of swelling were anterior lateral and posterior proximal, areas of thick underlying soft tissue. Identification of localised areas of swelling and atrophy and understanding of their effects on interface pressures could be used to improve individual socket design.  相似文献   

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