挤压膨化过程中食品营养成分的变化

总结了国内外近20年来对食品原料中主要营养成分,在挤压膨化过程中所发生的理化转变的研究进展。为开发有中国特色的膨化食品提供趋利避害的膨化工艺技术参考。

Alloying Effect Study on Thermodynamic Stability of MgH2 by First-principles Calculation

First-principles calculations based on density functional theory were performed to study the effect of alloying on the thermodynamic stability of MgH2 hydride （rutile and fluorite structures） with transitional metals （TM=Sc, Ti, Y） and group IIA elements （M=Ca, Sr, Ba）. The results indicate that fluorite structure of these hydrides are more stable than its relative rutile structure at low alloying content （less 20%）, structural destabilization of MgH2 appears in the alloying cases of Ti, Sr and Ba respectively. The structure-transition point from rutile structure to fluorite structure is at around 20% for MgH2-TM, and about 40% for MgH2-M. The formation enthalpy of fluorite Mg0.5Ba0.52 is about 0.3 eV and higher than that of fluorite MgH2, indicating that its hydrogen-desorption temperature at atmospheric pressure will be much lower than that of pure MgH2. Good consistency between experimental and calculated data suggests that above-adopted method is useful to predict structural transition and properties of MgH2 based hydrides for hydrogen storage.

Registration of image feature points using differential evolution

This paper introduces a robust global nonlinear optimizer—differential evolution(DE),which is a simple evolution algorithm to search for an optimal transformation that makes the best alignment of two sets of feature points.To map the problem of matching into the framework of DE,the objective function is proportional to the registration error which is measured by Hausdorff distance,while the parameters of transformation are encoded in floating-point as the functional variables.Three termination criteria are proposed for DE.A simulation of 2-dimensional point sets and a similarity transformation are presented to compare the robustness and convergence properties of DE with genetic algorithm’s (GA).And the registration of an object and its contour model have been demonstrated by using of DE to natural images.

Heterotopic pancreas in the gastrointestinal tract

Heterotopic pancreas is defined as pancreatic tissue found outside the usual anatomical location of the pancreas. It is often an incidental finding and can be found at different sites in the gastrointestinal tract. It may become clinically evident when complicated by pathological changes such as inflammation, bleeding, obstruction, and malignant transformation. In this report, a 60-year-old man with carcinoid syndrome caused by heterotopic pancreatic tissue in the duodenum is described, along with a 62-year-old man with abdominal pain caused by heterotopic pancreatic tissue in the gastric antrum. The difficulty of making an accurate diagnosis is highlighted. The patients remain healthy and symptom-free after follow-up of 1 year. Frozen sections may help in deciding the extent of resection intraoperatively. Although heterotopic pancreas is rare, it should be considered in the differential diagnosis of gastrointestinal stromal tumor.

Mode-Coupling Theory for Glass Transition of Active-Passive Binary Mixture

Collective behaviours of active particle systems have gained great research attentions in re- cent years. Here we present a mode-coupling theory （MCT） framework to study the glass transition of a mixture system of active and passive Brownian particles. The starting point is an eff）ctive Smoluchowski equation, which governs the dynamics of the probability dis- tribution function in the position phase space. With the assumption of the existence of a nonequilibrium steady state, we are able to obtain dynamic equations for the intermediate scattering functions （ISFs）, wherein an irreducible memory function is introduced which in turn can be written as functions of the ISFs based on standard mode-coupling approximations. The effect of particle activity is included through an effective difIusion coefficient which can be obtained via short time simulations. By calculating the long-time limit of the ISF, the Debye-Waller （DW） factor, one can determine the critical packing fraction ηc of glass transition. We find that for active-passive （AP） mixtures with the same particle sizes, ηc increases as the partial fraction of active particle xA increases, which is in agreement with previous simulation works. For system with different active/passive particle sizes, we find an interesting reentrance behaviour of glass transition, i.e., ηc shows a non-monotonic dependence on xa. In addition, such a reentrance behaviour would disappear if the particle activity is large enough. Our results thus provide a useful theoretical scheme to study glass transition behaviour of active-passive mixture systems in a promising way.

Protective effects of 2,4-dihydroxybenzophenone against acetaminophen-induced hepatotoxicity in mice

AIM:To examine the effects of 2,4-dihydroxybenzophenone(BP-1),a benzophenone derivative used as an ultraviolet light absorbent,on acetaminophen(APAP)induced hepatotoxicity in C57BL/6J mice.METHODS:Mice were administered orally with BP-1 at doses of 200,400 and 800 mg/kg body weight respectively every morning for 4 d before a hepatotoxic dose of APAP(350 mg/kg body weight) was given subcutaneously.Twenty four hours after APAP intoxication,the serum enzyme including serum alaine aminotransferase(ALT),aspartate aminotransferase(AST),lactate dehydrogenase(LDH) were measured and liver histopathologic changes were examined.RESULTS:BP-1 administration dramatically reduced serum ALT,AST and LDH levels.Liver histopathological examination showed that BP-1 administration antagonized APAP-induced liver pathological damage in a dose-dependent manner.Further tests showed that APAP-induced hepatic lipid peroxidation was reduced significantly by BP-1 pretreatment,and glutathione depletion was ameliorated obviously.CONCLUSION:BP-1 can effectively protect C57BL/6J mice from APAP-induced hepatotoxicity,and reduction of oxidative stress might be part of the protection mechanism.

Glass Formation of n-Butanol： Coarse-grained Molecular Dynamics Simulations Using Gay-Berne Potential Model

Using coarse-grained molecular dynamics simulations based on Gay-Berne potential model, we have simulated the cooling process of liquid n-butanol. A new set of GB parameters are obtained by fitting the results of density functional theory calculations. The simulations are carried out in the range of 290-50 K with temperature decrements of 10 K. The cooling characteristics are determined on the basis of the variations of the density, the potential energy and orientational order parameter with temperature, whose slopes all show discontinuity. Both the radial distribution function curves and the second-rank orientational correlation function curves exhibit splitting in the second peak. Using the discontinuous change of these thermodynamic and structure properties, we obtain the glass transition at an estimate of temperature Tg=1204.10 K, which is in good agreement with experimental results 1104-1 K.

The Gravity Field Variation Caused by Inner Core Super Rotation

Due to the super rotation of the Earth＇s inner core, the tilted figure axis of the inner core would progress with respect to the mantle and thus cause the variation of the Earth＇s external gravity field. This paper improves the present model of the gravity field variation caused by the inner core super rotation. Under the assumption that the inner core is a stratifying ellipsoid whose density function is fitted out from PREM and the super rotation rate is 0.27-0.53°/yr, calculations show that the global temporal variations on the Earth＇s surface have a maximum value of about 0.79-1.54×10^3 pGal and a global average intensity of about 0.45-0.89×10^ 3 μGal in the whole year of 2007, which is beyond the accuracy of the present gravimetry and even the super conducting gravimeter data. However, both the gravity variations at Beijing and Wuhan vary like sine variables with maximal variations around 0.33 pGal and 0.29 pGal, respectively, in one cycle. Thus, continuous gravity measurements for one or two decades might be able to detect the differential motion of the inner core.