高交联玉米淀粉的非晶化特性

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。     

乙酰化二淀粉磷酸酯性质的研究

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。     

高交联木薯淀粉的非糊化特性

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     

食用淀粉磷酸单酯的研究

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。     

醚化、交联对玉米淀粉功能性质的影响

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。     

三偏磷酸钠交联玉米淀粉颗粒膨胀历程及结构特征

利用淀粉与三偏磷酸钠的交联反应,通过控制交联反应程度,成功地控制了交联淀粉颗粒膨胀程度并使其停留在不同的溶胀阶段,详细研究了处在不同溶胀阶段交联淀粉颗粒的结构特征和变化趋势,揭示了三偏磷酸钠交联玉米淀粉颗粒的膨胀历程及结构特征,即随着淀粉颗粒交联程度的降低,颗粒的膨胀历程由中心脐点处爆裂膨胀方式转化为颗粒整体向外的均匀膨胀方式.     

三种交联酯化冷水可溶淀粉性质的比较

通过不同工艺路线制备了相应的交联酯化冷水可溶淀粉，分别称为a、b、c淀粉，对它们的性质作了对比研究，结果发现，不同的工艺路线制备出的淀粉性质存在差异。a淀粉交联度最高，酯化取代度最低，在冷水中容易分散，形成的糊的粘度热稳定性好，但透明度差，容易凝沉；c淀粉交联度最低，酯化取代度最高，在冷水中不易分散，形成的糊的粘度热稳定性差，但透明度好，不易凝沉；b淀粉性质居于两者之间。     

高温水分散体系交联玉米淀粉的非晶化现象研究

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.     

交联羧甲基红薯淀粉吸附废水中Pb^2＋的研究

以红薯淀粉为原料,选用环氧氯丙烷作交联剂,氯乙酸作羧甲基化试剂,合成了交联-羧甲基复合变性淀粉,研究交联-羧甲基淀粉在水处理中吸附Pb2+的影响因素.结果表明,Pb2+的吸附量与取代度、淀粉量、Pb2+起始质量浓度、温度、pH和吸附时间有关,吸附符合朗缪尔的等温吸附线,淀粉再生能力良好.     

淀粉来源及预处理方式对淀粉接枝共聚反应的影响

以[Mn(H2P2O7)3]3-为引发剂,对不同来源淀粉与丙烯腈的接枝共聚反应进行了研究,考察了淀粉预处理方式对淀粉接枝共聚反应的影响.结果显示:用颗粒淀粉进行接枝共聚反应时,接枝效果受到淀粉颗粒大小的影响;用糊化后的淀粉进行接枝共聚反应时,最终制得产物的吸水率较高,并部分地依赖淀粉中直链和支链淀粉的含量.淀粉的预处理如糊化、氧化、酸解对接枝效果都有一定的影响.     

Body composition assessment and methodology in nonathletic and athletic adolescent and adult males and females

The purpose of this review is to outline methodology for assessing body composition utilizing anthropometric and densitometric techniques. The objective of body composition assessment is to measure body fat and lean body mass. The quantity of these components varies due to growth, physical activity, dietary regimens, and aging. Anthropometric techniques incorporate selected skinfolds, circumferences, skeletal widths, or other variables to estimate body composition within k2.0-4.0%. These techniques are adequate for field testing of groups or individuals, but are population specific. Densitometry measures body volume irrespective of physique, sex, or age. This laboratory technique estimates body composition within 1.0-2.0%, is more difficult to administer, but is not population specific. Some limitation exists with any present technique due to biological variability and incomplete research of reference body composition in children, females, and the aged. J Orthop Sports Phys Ther 1984;5(6):336-347.     

Perioperative and long-term morbidity and mortality after above-knee and below-knee amputations in diabetics and nondiabetics

We performed a retrospective review of a vascular surgery quality assurance database to evaluate the perioperative and long-term morbidity and mortality of above-knee amputations (AKA, n = 234) and below-knee amputations (BKA, n = 720) and to examine the effect of diabetes mellitus (DM) (181 of AKA and 606 of BKA patients). All patients in the database who had AKA or BKA from 1990 to May 2001 were included in the study. Perioperative 30-day cardiac morbidity and mortality and 3-yr and 10-yr mortality after AKA or BKA were assessed. The effect of DM on 30-day cardiac outcome was assessed by multivariate logistic regression and the effect on long-term survival was assessed by Cox regression analysis. The perioperative cardiac event rate (cardiac death or nonfatal myocardial infarction) was at least 6.8% after AKA and at most 3.6% after BKA. Median survival was significantly less after AKA (20 mo) than BKA (52 mo) (P < 0.001). DM was not a significant predictor of perioperative 30-day mortality (odds ratio, 0.76 [0.39-1.49]; P = 0.43) or 3-yr survival (Hazard ratio, 1.03 [0.86-1.24]; P = 0.72) but predicted 10-yr mortality (Hazard ratio, 1.34 [1.04-1.73]; P = 0.026). Significant predictors of the 30-day perioperative mortality were the site of amputation (odds ratio, 4.35 [2.56-7.14]; P < 0.001) and history of renal insufficiency (odds ratio, 2.15 [1.13-4.08]; P = 0.019). AKA should be triaged as a high-risk surgery while BKA is an intermediate-risk surgery. Long-term survival after AKA or BKA is poor, regardless of the presence of DM.     

Postoperative nausea and vomiting and opioid-induced nausea and vomiting: guidelines for prevention and treatment

Postoperative nausea and vomiting (PONV) causes patient discomfort, lowers patient satisfaction, and increases care requirements. Opioid-induced nausea and vomiting (OINV) may also occur if opioids are used to treat postoperative pain. These guidelines aim to provide recommendations for the prevention and treatment of both problems. A working group was established in accordance with the charter of the Sociedad Espa?ola de Anestesiología y Reanimación. The group undertook the critical appraisal of articles relevant to the management of PONV and OINV in adults and children early and late in the perioperative period. Discussions led to recommendations, summarized as follows: 1) Risk for PONV should be assessed in all patients undergoing surgery; 2 easy-to-use scales are useful for risk assessment: the Apfel scale for adults and the Eberhart scale for children. 2) Measures to reduce baseline risk should be used for adults at moderate or high risk and all children. 3) Pharmacologic prophylaxis with 1 drug is useful for patients at low risk (Apfel or Eberhart 1) who are to receive general anesthesia; patients with higher levels of risk should receive prophylaxis with 2 or more drugs and baseline risk should be reduced (multimodal approach). 4) Dexamethasone, droperidol, and ondansetron (or other setrons) have similar levels of efficacy; drug choice should be made based on individual patient factors. 5) The drug prescribed for treating PONV should preferably be different from the one used for prophylaxis; ondansetron is the most effective drug for treating PONV. 6) Risk for PONV should be assessed before discharge after outpatient surgery or on the ward for hospitalized patients; there is no evidence that late preventive strategies are effective. 7) The drug of choice for preventing OINV is droperidol.