小麦糊化特性参数稳定性分析及其与其它品质性状关系的研究

通过测定黄淮麦区2年度3试点13个小麦区试品种糊化特性(RVA)参数及其它主要品质性状,研究了小麦RVA参数稳定性及其与其它主要品质性状间的关系.结果表明:基因型对峰值粘度、保持粘度、稀懈值、最终粘度、回升值起主导作用,环境对糊化温度和峰值时间影响较大.峰值粘度、保持粘度、最终粘度在品种间变幅较大,分别为2 055.50 cp～3 935.50 cp、1 046.42 cp～2 589.00 cp和2 412.00 cp～4 341.50 cp,峰值粘度、保持粘度、稀懈值的变异系数较高,分别为10.74 %、12.17 %、21.25 %.除峰值时间外,其它RVA参数品种间差异极显著.峰值粘度与保持粘度、稀懈值、最终粘度及回升值间极显著正相关.峰值粘度、保持粘度、最终粘度、回升值与蛋白质含量、湿面筋含量和Zeleny沉降值间极显著负相关.同时依据RVA参数对参试品种进行了聚类分析.峰值粘度可作为衡量小麦淀粉特性的最重要指标,由于品种间淀粉品质差异大,因此品种选育过程中应同时注重蛋白质和淀粉品质.     

Food Viscosity Influences Caloric Intake Compensation and Body Weight in Rats

Objective: To determine the effects of food viscosity on the ability of rats to compensate for calories in a dietary supplement. Research Methods and Procedures: In a series of four experiments, rats consumed dietary supplements equated for caloric and nutritive content but differing in viscosity. Experiments 1 to 3 examined the ability of the rats to compensate for the calories consumed in low‐ compared with high‐viscosity premeals by reducing intake of a subsequent test meal. Caloric compensation was assessed with a wide range of premeal viscosity levels and with two different non‐nutritive thickening agents. Experiment 4 assessed the effects of consuming daily a low‐viscosity compared with an equicaloric high‐viscosity dietary supplement on longer term body weight gain. Results: Consuming a lower viscosity premeal was followed by significantly more caloric intake (i.e., less caloric compensation) compared with consuming premeals with higher viscosity levels. This effect was not specific to one thickening agent. Furthermore, rats given a low‐viscosity supplement daily gained significantly more weight over a 10‐week period compared with rats given a high‐viscosity supplement. Discussion: The results of these experiments suggest that food viscosity may be an important determinant of short‐term caloric intake and longer term body weight gain.     

No change of whole blood of plasma viscosity in cardiac patients after subcutaneous calcium heparin.

Whole blood viscosity, plasma viscosity and haematocrit were studied in a group of cardiac patients before and during subcutaneous heparin treatment. No significant change was noted in any of the parameters investigated. Relative viscosity (whole blood viscosity/plasma viscosity ratio) was also unaffected. These data indicate that heparin has no effect on the rheology of blood in vitro.     

Homeostasis of plasma membrane viscosity in fluctuating temperatures

Temperature has a direct effect at the cellular level on an organism. For instance, in the case of biomembranes, cooling causes lipids to lose entropy and pack closely together. Reducing temperature should, in the absence of other factors, increase the viscosity of a lipid membrane. We have investigated the effect of temperature variation on plasma membrane (PM) viscosity. We used dispersion tracking of photoactivated green fluorescent protein (GFP) and fluorescence recovery after photobleaching in wild-type and desaturase mutant Arabidopsis thaliana plants along with membrane lipid saturation analysis to monitor the effect of temperature and membrane lipid composition on PM viscosity. Plasma membrane viscosity in A. thaliana is negatively correlated with ambient temperature only under constant-temperature conditions. In the more natural environment of temperature cycles, plants actively manage PM viscosity to counteract the direct effects of temperature. Plasma membrane viscosity is regulated by altering the proportion of desaturated fatty acids. In cold conditions, cell membranes accumulate desaturated fatty acids, which decreases membrane viscosity and vice versa. Moreover, we show that control of fatty acid desaturase 2 (FAD2)-dependent lipid desaturation is essential for this homeostasis of membrane viscosity. Finally, a lack of FAD2 function results in aberrant temperature responses.     

Effects of the non-Newtonian viscosity of blood on flows in a diseased arterial vessel. Part 1: Steady flows

Effects of the non-Newtonian viscosity of blood on a flow in a coronary arterial casting of man were studied numerically using a finite element method. Various constitutive models were examined to model the non-Newtonian viscosity of blood and their model constants were summarized. A method to incorporate the non-Newtonian viscosity of blood was introduced so that the viscosity could be calculated locally. The pressure drop, wall shear stress and velocity profiles for the case of blood viscosity were compared for the case of Newtonian viscosity (0.0345 poise). The effect of the non-Newtonian viscosity of blood on the overall pressure drop across the arterial casting was found to be significant at a flow of the Reynolds number of 100 or less. Also in the region of flow separation or recirculation, the non-Newtonian viscosity of blood yields larger wall shear stress than the Newtonian case. The origin of the non-Newtonian viscosity of blood was discussed in relation to the viscoelasticity and yield stress of blood.     

籼型杂交稻淀粉RVA谱特征值的杂种优势分析

以6个籼型三系不育系和5个籼型恢复系按不完全双列杂交设计配制的30个杂交稻组合及其亲本为材料,对其籽粒淀粉RVA谱各特征值进行了测定和分析。结果表明：（1）亲本间和杂交稻组合间的淀粉RVA谱各特征值均存在极显著的差异,其中变异最大的是消减值,最小的是糊化开始温度。（2）杂交稻组合淀粉RVA谱各特征值的变异系数均小于杂交稻亲本的变异系数;峰值粘度、崩解值、最低粘度和最终粘度的平均值杂交稻组合大于亲本,其他性状的平均值杂交稻组合小于亲本。（3）峰值粘度存在极显著的正向超亲优势;崩解值、最低粘度、最终粘度和回复值存在极显著的正向中亲优势;消减值和峰值时间存在极显著的负向中亲优势和正向低亲优势;糊化开始温度存在极显著的负向低亲优势;最终粘度、回复值和糊化开始温度表现为极显著的负向竞争优势,其他性状表现为正向竞争优势。（4）峰值粘度、崩解值、消减值和回复值等4个性状,各杂交稻组合与其母本、中亲值呈现极显著正相关,峰值时间与中亲值呈显著正相关。而与其父本的相关均未达显著水平。     

Simultaneous detection of SO2 and viscosity in drug-induced inflammation in live cells and zebrafish

The viscosity within cells is a crucial microenvironmental factor, and sulfur dioxide (SO₂) has essential functions in regulating cellular apoptosis and inflammation. Some evidence has been confirmed that changes in viscosity and overexposure of SO₂ within the cell may cause detrimental effects including, but not limited to, respiratory and cardiovascular illnesses, inflammation, fatty liver, and various types of cancer. Therefore, precise monitoring of SO₂ and viscosity in biological entities holds immense practical importance. Therefore, in this research, we developed a versatile fluorescent TCF-Cou that enables the dual detection of SO₂ and viscosity in the living system. Probe TCF-Cou possessed a response to viscosity and SO₂ through red and green emissions. The alteration of SO₂ and viscosity levels in live cells and zebrafish were also monitored using probe TCF-Cou. We hope that this fluorescent probe could be a potential tool for revealing the related pathological and physiological processes through monitoring the changes in SO₂ and viscosity.     

Light- and nucleotide-dependent increase in apparent viscosity in a suspension of retinal disks

Light triggers the cyclic nucleotide cascade in photoreceptor disk membranes. We report here that light-induced changes in the apparent viscosity of disk membrane suspensions can also be observed using either native disk membranes or washed membranes reconstituted with G protein and PDE. The viscosity changes are light- and GTP-dependent and require the presence of G protein and PDE. The magnitude of the viscosity change increases with increasing membrane concentration. Under the same conditions in which light elicits a change in viscosity, we observe a large increase in light scattering by the disk membrane suspension.     

Intracellular viscosity: Methods of measurement and role in metabolism

This review is devoted to the study of intracellular viscosity. Methods of intracellular viscosity measurement in cell populations and single cells are characterized and critically evaluated. Examples of intracellular viscosity assessment in a number of various cell types and intracellular organelles are presented. The main results of the in vitro and in vivo studies on the role of viscosity in metabolism are discussed.     

Evaluation of various hemorheologic parameters in diabetes mellitus

It has been speculated that changes in intrinsic blood flow properties may contribute to the evolution of vascular complications in diabetes mellitus. To verify this hypothesis we measured hematocrit, fibrinogen, plasma and blood viscosity in 30 diabetic patients and in 25 healthy volunteers. Diabetics showed blood and plasma viscosity and fibrinogenemia higher than healthy subjects, although only plasma viscosity and fibrinogenemia were statistically significant (p less than 0.001). Moreover the diabetic patients with the highest HbAlc values had a significant increase in plasma viscosity compared with the patients with lower HbAlc values (p less than 0.001), despite a similar fibrinogenemia. This study confirms the presence of hemorheological changes in diabetes mellitus and shows a correlation between plasma viscosity and metabolic control.     

Risk factors evaluation in some cardiovascular diseases

Cardiovascular risk factors are associated with limitations of blood fluidity. Rheological behaviour of blood in transient flow may result from the internal organization, which in turn depends upon many parameters, which may be considered as possible elements of a profiling algorithm for diagnostic and prognostic values in various pathophysiological states. This study was designed to investigate haemorheological parameters in patients being treated for hypertension, coronary heart disease and myocardial infarct. On the basis of plasma viscosity, whole blood viscosity, haematocrit, red cell aggregation and red cell deformation, the risk was evaluated. In cases of hypertension there was a significant rise in plasma viscosity, whole blood viscosity, red cell aggregation and a fall in red cell deformability. In cases of coronary disease, plasma viscosity and red cell aggregation was increased, while in patients with myocardial infarcts, where the degree of severity is greater it was found that there was a significant rise in both plasma and whole blood viscosity. Haematocrit values were unaffected in all three groups.     

Theory for flow of Casson and Herschel-Bulkley fluids in cone-plate viscometers

Mathematical models for blood flow in cone-plate viscometer have been considered, by assuming blood as a Casson/Herschel-Bulkley fluid. Three different cases have been analyzed (i) when there is no shearing, (ii) partial shearing and (iii) full shearing. The relationships between the angular velocity and torque have been obtained for the above three cases. By assuming total shearing, the analytical expression for apparent viscosity has been obtained. Variation of apparent viscosity with yield stress, angular velocity, Casson co-efficient of viscosity, consistency index and flow behaviour index has been computed. It is observed that as the angular velocity increases, the apparent viscosity decreases for both fluids. Further, it is found that as the cone angle increases, the apparent viscosity increases. This behaviour of apparent viscosity in cone-plate viscometer is interesting and unexpected and is being reported first time.     

Cholinergic control of the mechanical properties of the catch connective tissue in the holothurian body wall

Effects of acetylcholine (ACh), ACh-agonists and antagonists were studied on the viscosity of the dermis of the sea cucumber Holothuria leucospilota. ACh and nicotinic agonists caused an early increase in viscosity and late decrease. Muscarinic agonists produced a viscosity decrease. The viscosity increase elicited by nicotine was inhibited by tubocurarine. The viscosity decrease caused by methacholine was suppressed by atropine. The mechanical properties of this connective tissue are very likely controlled by both nicotinic and muscarinic cholinoreceptors.     

Rheological characteristics of the blood in long-term and quick adaptation to muscle loads

It was established in chronic experiments on 26 dogs that long-term adaptation to regular muscular activity caused a 19.6-46.1% decrease in blood viscosity. Hematocrit was lowered and red cell deformability improved. A correlation was observed between blood viscosity and its oxygen transport function. As a result of muscular training the role of plasma protein in blood viscosity increased and that of red cells declined. Single muscular activity produced a 48.2-81% increase in blood viscosity, while plasma viscosity remained unchanged. Trained animals had lower absolute values of blood viscosity even at the time of muscular effort as compared to those in untrained animals at rest.     

Relation between blood plasma viscosity and presence of vascular and neurological complications in diabetic Africans

The relation between changes in plasma and serum viscosity and the presence of diabetic vascular and neurological complications was investigated in 50 diabetic Africans. Diabetics with complications had significantly elevated plasma and serum viscosity compared with those of both diabetics without complications and healthy non-diabetics. Hypertension also contributed to the elevation of plasma and serum viscosity in diabetics with complications. Plasma and serum viscosity of diabetics significantly correlated with the number of vascular and neurological complications. Diabetics with cerebrovascular disease had the highest plasma and serum viscosity due to the presence of many complications. The results of this study suggest that changes in plasma and serum viscosity may be associated with abnormalities of vascular and neurological function present in diabetic Africans.     

Detection of red cell aggregation by low shear rate viscometry in whole blood with elevated plasma viscosity

The viscosity of whole blood measured at low shear rates is determined partly by shear resistance of the red cell aggregates present, stronger aggregation increasing the viscosity in the absence of other changes. Effects of cell deformability can confound interpretation and comparison in terms of aggregation, however, particularly when the plasma viscosity is high. We illustrate the problem with a comparison of hematocrit-adjusted blood from type 1 diabetes patients and controls in which it is found the apparent and relative viscosities at a true shear rate of 0.20 s-1 are lower in the patient samples than age matched controls, in spite of reports that aggregation is increased in such populations. Because the plasma viscosities of the patients were higher on average than controls, we performed a series of experiments to examine the effect of plasma protein concentration and viscosity on normal blood viscosity. Dilution or concentration by ultrafiltration of autologous plasma and viscosity measurements at low shear on constant hematocrit red cell suspensions showed (a) suspension viscosity at 0.25 and 3 s-1 increased monotonically with plasma protein concentration and viscosity but (b) the relative viscosity increased, in concert with the microscopic aggregation grade, up to a viscosity of approximately 1.25 mPa-s but above this the value the relative viscosity no longer increased as the degree of aggregation increased in concentrated plasmas. It is suggested that in order to reduce cell deformation effects in hyperviscous pathological plasmas, patient and control plasmas should be systematically diluted before hematocrit is adjusted and rheological measurements are made. True shear rates should be calculated. Comparison of relative viscosities at low true shear rates appears to allow the effects of red cell aggregation to be distinguished by variable shear rate viscometry in clinical blood samples.     

肠淋巴液引流对失血性休克大鼠红细胞流变性的影响

目的:观察肠淋巴液引流对失血性休克大鼠红细胞流变性指标以及血液黏度的作用。方法:Wistar雄性大鼠均分为假休克组、休克组(复制失血性休克模型)、引流组(复制失血性休克模型,自低血压1 h引流休克肠淋巴液)。在低血压3 h或相应时间,经腹主动脉取血,检测红细胞参数、红细胞电泳、红细胞沉降率(ESR)以及血液黏度,计算红细胞聚集指数、红细胞变形指数。结果:与假休克组比较,休克组红细胞数量、红细胞比积(HCT)、血红蛋白(Hb)、平均红细胞血红蛋白浓度(MCHC)、红细胞电泳率与迁移率、红细胞变形指数、全血黏度、全血低切与高切相对黏度和还原黏度显著降低,休克组平均红细胞体积、红细胞电泳时间、ESR、血沉方程K值与校正K值、红细胞聚集性指数、血浆黏度显著升高;引流组MCHC、红细胞电泳率与迁移率、全血黏度、全血低切与高切还原黏度均显著降低,引流组红细胞体积分布宽度(RDW-SD)显著增加。同时,引流组HCT、RDW-SD、红细胞变形指数、全血黏度、全血低切与高切相对黏度显著高于休克组;ESR、血沉方程K值与校正K值、红细胞聚集性指数、血浆黏度显著低于休克组。结论:休克肠淋巴液引流可改善失血性休克大鼠红细胞流变行为,从而改善血液流变性。     

Characterization of changes in the viscosity of lipid membranes with the molecular rotor FCVJ

Membrane viscosity is a key parameter in cell physiology, cell function, and cell signaling. The most common methods to measure changes in membrane viscosity are fluorescence recovery after photobleaching (FRAP) and fluorescence anisotropy. Recent interest in a group of viscosity sensitive fluorophores, termed molecular rotors, led to the development of the highly membrane-compatible (2-carboxy-2-cyanovinyl)-julolidine farnesyl ester (FCVJ). The purpose of this study is to examine the fluorescent behavior of FCVJ in model membranes exposed to various agents of known influence on membrane viscosity, such as alcohols, dimethyl sulfoxide (DMSO), cyclohexane, cholesterol, and nimesulide. The influence of key agents (propanol and cholesterol) was also examined using FRAP, and backcalculated viscosity change from FCVJ and FRAP was correlated. A decrease of FCVJ emission was found with alcohol treatment (with a strong dependency on the chain length and concentration), DMSO, and cyclohexane, whereas cholesterol and nimesulide led to increased FCVJ emission. With the exception of nimesulide, FCVJ intensity changes were consistent with expected changes in membrane viscosity. A comparison of viscosity changes computed from FRAP and FCVJ led to a very good correlation between the two experimental methods. Since molecular rotors, including FCVJ, allow for extremely easy experimental methods, fast response time, and high spatial resolution, this study indicates that FCVJ may be used to quantitatively determine viscosity changes in phospholipid bilayers.     

Changes in mechanical properties with DMSO-induced differentiation of HL-60 cells.

We measured changes in the deformability of human promyelocytic leukemic (HL-60) cells induced to differentiate for 5-6 days along the granulocyte pathway by 1.25% dimethylsulfoxide (DMSO). Differentiation resulted in an approximately 90% reduction in the transit times of the cells through capillary-sized pores over a range of aspiration pressures. Cell volume, as measured by two methods, decreased by an average of 35%. To account for the contribution of the volume decrease to the decrease in transit time, the liquid drop model, developed to describe neutrophil deformability, was used to calculate an apparent viscosity of the cells during this deformation. The apparent viscosity of both uninduced and induced HL-60 cells was a function of aspiration pressure, and an approximately 80% reduction in viscosity occurred with induction, as determined by regression analysis. The deformation rate-dependent viscosities of the induced cells were between 65 and 240 Pa-sec, values similar to those measured for circulating neutrophils. To assess the role of polymerized actin in these viscosity changes, intracellular F-actin content was measured, and the effect of dihydrocytochalasin B (DHB), an agent that disrupts actin polymerization, was determined. Despite the significant decrease in cellular viscosity, F-actin content per cell volume did not change significantly after induced differentiation. Treatment with 3 and 30 microM DHB lowered cellular F-actin content in a dose-dependent manner in both uninduced and induced cells. Cellular viscosity of both uninduced and induced cells decreased sharply with 3 microM DHB treatment (85% and 76% respectively). 30 microM DHB treatment caused a further significant reduction in the viscosity of uninduced cells, but for induced cells the additional decrease in viscosity was not significant. These data indicate that reductions in both cell volume and intrinsic viscosity contribute to the increased deformability of HL-60 cells with DMSO-induced differentiation. However, changes in the concentration of F-actin cannot account for the decrease in cellular viscosity that occurs.     

Blood viscosity and cardiac output in acute experimental anemia.

The significance of blood viscosity alterations during anemia was evaluated in dogs under morphine-chloralose anesthesia. In group I, anemia (mean hematocrit 18.1 +/- 1.3 vol %) was produced by exchange transfusion with clinical dextran (avg mol wt 70,000). In group II, anemia was produced (mean hematocrit 19.9 +/- 0.88 vol %) with 500,000 molecular weight dextran, thus preventing the decrease in blood viscosity in group I. The cardiac output increase in group I (93.4%) with low-viscosity anemia was significantly greater than in group II (43.3%) with unchanged blood viscosity. Group III animals were transfused with a clinical dextran-red cell mixture, and group IV animals received a 500,000 mol wt dextran-red cell mixture. In group III, blood viscosity and cardiac output did not change. In group IV, blood viscosity rose and cardiac output fell significantly. The results suggest that a change in blood viscosity exerts a significant effect upon cardiac output, especially during acute dextran-exchange anemia.