Some Biochemical Aspects of the Protective Effect of Strontium Chloride on Gamma-Irradiated Rats

The effect of treatment with SrCl₂ (10 mg/100 g rat) on rats 15 minutes prior to whole body γ-irradiation (7,5 Gy) was studied. The hazardeous effect of irradiation were greatly corrected in the treated group. The hyperglycemic effect and liver glycogen accumulation in the untreated group decreased to normal level. The enzymatic activities of serum alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase and lactate dehydrogencase were greatly affected showing insignificant changes in the treated group of animals. Life span calculated on 50% survival was also significantly elongated by 36.3%. These results show the potentiality of SrCl₂ as a radioprotective agent which was not used before.     

Interaction of therapeutic ultrasound with purified enzymes in vitro

The effects of ultrasound on the rates of the catalytic reactions of four purified enzymes in vitro have been extensively investigated under a wide range of biochemical and physical exposure conditions. In general, it can be concluded that therapeutic intensities of continuous wave 0.88 MHz ultrasound had no detectable direct effects on the rates of the reactions catalysed by creatine kinase, lactate dehydrogenase, hexokinase and pyruvate kinase. Some minor effects were noted. These were: an indirect effect resulting from mixing within the sample chamber caused by quartz wind streaming; an effect on partially-hydrated cross-linked enzyme systems which appears to be the result of increased fluid penetration of the solid matrix in the presence of ultrasound; and an increase in the rate of spontaneous dissociation of a multimeric enzyme system. It is, therefore, concluded that a direct interaction between ultrasound and the catalytic functioning of individual enzyme molecules is unlikely to be the primary step in any acousto-biological interaction, and that this primary interaction appears to be occurring at a higher level of organizational complexity.     

Mechanisms underlying the effects of ultrasound-assisted alkaline extraction on the structural properties and in vitro digestibility of Tenebrio molitor larvae protein

Edible insects have been considered as a sustainable and novel protein source to replace animal-derived proteins. The present study aimed to extract Tenebrio molitor larvae proteins (TMP) using ultrasound-assisted alkaline extraction (UAE). Effects of different UAE times (10, 20, 30, 40, and 50 min) on the structural properties and in vitro digestibility of TMP were comparatively investigated with the traditional alkaline extraction method. The results revealed that ultrasonication could effectively alter the secondary/tertiary structures and thermal stability of TMP during UAE. The molecular unfolding and subsequent aggregation of TMP during UAE were mainly attributed to the formation of disulfide bonds and hydrophobic interactions. Moreover, TMP extracted by UAE had higher in vitro digestibility and digestion kinetics than those extracted without ultrasound, and the intermediate UAE time (30 min) was the optimal ultrasound parameter. However, longer UAE times (40 and 50 min) lowered the digestibility of TMP due to severe protein aggregation. The present work provides a potential strategy for the extraction of TMP with higher nutritional values.     

The C (2 Π)→X(2Σ+) transition in thermal emission spectra of the diatomic alkaline earth bromides) transition in thermal emission spectra of the diatomic alkaline earth bromides

The extensive thermal emission spectrum attributed to the diatomic bromides of calcium, strontium and barium has been observed in the visible region at temperatures about 2200–2400° C, using a vacuum graphite furnace. Many new bands,viz., 141 in CaBr, 53 in SrBr and 68 in BaBr, have been recorded and classified. The vibrational constants agree with those determined by earlier workers and involved the ground state in each case. The transition C→X apears in each molecule and consists of two equally intense systems,viz., C₁→X and C₂→X. The general spectroscopic features of the C→X systems of the bromides of the II A sub group of the periodic table have been compared. They exhibit a close structural similarity and furnish a good example of homologous spectra. The system C→X in all these molecules arises from a C² π−X² Σ ⁺ transition where the² π state appears to be intermediate between Hund’s cases (a) and (b).     

Elastic properties of alkaline earth oxides under high pressure

In this article, we have investigated the high-pressure structural phase transition of alkaline earth oxides using the three-body potential (TBP) model. Phase transition pressures are associated with elastic constants. An effective inter-ionic interaction potential (TBP) with long-range Coulomb interactions and the Hafemeister–Flygare type short-range overlap repulsion and the vdWl interaction is developed. The present calculations have revealed reasonably good agreement with the available experimental data on structural transition (B1–B2 structure). The phase transition pressures Pt of MgO, CaO, SrO, and BaO occur at 220, 45, 40, and 100?GPa, respectively. Further, the variations of the second-order elastic constants with pressure have followed a systematic trend, which are almost identical to those exhibited by the observed data measured for other semiconducting compounds with rocksalt (B1)-type crystal structure. It is found that TBP promises that we would be able to predict phase transition pressure and elastic constants for other chalcogenides as well. The results may be useful for geophysical study.     

Mn掺杂对BaSn1-xMnxO3体系结构、光学和磁学性质的影响

利用传统的固相反应法制备了BaSn1-xMnxO3(x=0,0.05,0.10和0.13)多晶样品,系统研究了不同Mn掺杂量对BaSnO3样品的结构、光学及磁学性质的影响.通过X射线衍射分析表明此掺杂化合物形成了具有钙钛矿结构的单相,在掺杂范围内没有观察到第二相出现.漫反射光谱测试分析发现随着Mn掺杂浓度的增加,其光学吸收边红移并逐渐平缓化,拉曼光谱测试表明拉曼振动模式也发生了变化,进一步证明Mn离子取代了Sn位.磁场下的光致发光谱测试表明样品在近红外区的发光可能与Sn离子有关.磁学测量则显示样品在低温具有一定铁磁性,其来源可用F心交换机制来解释.     

Ca5N4高压新相的第一性原理研究

通过在氮中引入杂质离子,利用高压手段获得具有新奇结构的多氮化合物是目前被广泛应用的研究方法.钙氮材料在催化、光电方面有着广泛的应用.具有较低电离能的钙(Ca)元素很容易和氮原子形成离子键钙氮化物.高压为寻找新型钙氮化合物提供了全新的技术途径.因此,利用高压方法,通过改变配比的方式,寻找具有新奇特性的钙氮高压结构,是一项非常有意义的工作.本文利用基于密度泛函理论的结构搜索方法,在100 GPa条件下,通过预测得到了一个稳定的Ca5N4相.该结构内部氮原子之间以N-N共价单键键合,氮原子和钙原子之间是离子键相互作用,且钙氮之间的电荷转移量为1.26 e/N atom.能带结构计算表明P 21/c-Ca5N4是一个直接带隙为1.447 eV的半导体结构.最后,系统地给出了该结构的拉曼振动光谱,并指认了拉曼振动模式,为实验合成该结构提供了理论指导.     

超声波对固定化酶活性的影响

本文介绍了超声波对固定化酶的影响，同时对作用过程中的影响因素进行了阐述，并探讨了超声波影响固定化酶的可能机理。     

新型电极材料Sb掺杂BaSnO3薄膜的外延生长及其在铁电薄膜电容器中的应用

本文利用脉冲激光沉积技术在SrTiO_3单晶衬底上生长了Sb掺杂BaSnO_3(BSSO)外延薄膜.结构和输运性质测量结果显示BSSO薄膜是一种具有立方钙钛矿结构导电性很好的薄膜材料,80K时呈现金属绝缘体转变,室温下薄膜的电阻率、载流子浓度和迁移率分别为ρ=2.43 mΩcm,n=1.65×1021 cm~(-3)和μ=1.75 cm~2/Vs.以BSSO薄膜为底电极制备了具有比较好电滞回线的Pb(Zr_(0.52)Ti_(0.48))O_3和Bi(Mn_(0.05)Fe_(0.95))O_3铁电电容器,表明BSSO薄膜是一种具有应用前景的新型电极材料.     

Effect of the crystal potential on electronic polarizabilities of ions in alkaline earth chalcogenides

The electronic polarizabilities of ions in alkaline earth chalcogenides are estimated by taking account of the effect of the crystalline potential. The polarizabilities thus obtained are found to present a good agreement with experimental data. It has been shown that the polarizabilities and radii of alkaline earth and chalcogenide ions follow the polarizability-radius cube relation approximately well.     

Synthesis and Photoluminescence of Tetravalent Cerium-Doped Alkaline-Earth-Metal Tungstate Phosphors by a Co-precipitation Method

A series of tetravalent cerium ion-doped alkaline-earth-metal tungstate phosphors were prepared by a co-precipitation method with a mixture of ammonium bicarbonate and aqueous ammonia as the precipitating agent. X-ray diffraction, scanning electron microscopy, and photoluminescence were used to characterize the structure, morphology, and luminescent properties of the phosphors. The synthesized cerium-doped tungstate phosphors have a scheelite structure with a pure phase. The scanning electron microscope images show that the grain sizes are in the range from 1.0 to 3.0 µm. Photoluminescence spectra indicate blue emission around 440 nm and the optimized concentrations of tetravalent cerium were 3.0, 2.0, and 3.0 in calcium tungstate, strontium tungstate, and barium tungstate for the highest emission intensities at 365 nm excitation. The Commission Internationale De L'E'clairage chromaticity coordinates of cerium-doped tungstate phosphors, that is, x = 0.14, y = 0.14, exhibit pure blue emission and the synthesized phosphors are promising materials for visual display and solid-state lighting applications.     

新型添加剂对单晶硅表面金字塔形貌的影响

单晶硅表面微结构对晶体硅光电转换性能有非常重要的影响, 晶体硅表面微结构的调节技术一直是半导体、 太阳能电池领域研究的热点之一.利用碱液与单晶硅异向腐蚀特性的刻蚀技术, 在单晶硅表面可以获得布满金字塔的绒面, 但普通碱液刻蚀的绒面, 其金字塔大小、 形貌和分布随机性大, 不利于提高硅太阳电池的转换效率.在普通的碱腐蚀液中加入不同量的特种添加剂, 然后在相同的温度、 时间下刻蚀单晶硅表面, 通过观察样品表面SEM图, 发现在普通碱液中加入适量添加剂后刻蚀的单晶硅表面能形成均匀密集分布金字塔, 金字塔大小在2—4μupm 之间, 棱边圆滑, 表面金字塔覆盖率高; 用积分反射仪测量了样品的反射率曲线, 发现样品平均反射率下降到12.51%.实验结果表明, 在普通碱液中加入特种添加剂, 能控制单晶硅表面金字塔的大小和分布.     

氧化物膜包覆碱土硫化物荧光粉的研究

采用湿法在碱土硫化物为基质的红色长余辉发光材料Ca0.8Sr0.2S：Eu^2 ,Tm^3 表面包覆一层惰性的氧化物膜,使其与外界的环境相隔离,从而提高其化学稳定性。用XRD、SEM及能谱表征了氧化物惰性膜的存在,讨论了核-壳结构间的键合作用;同时还测定了包膜前后荧光粉发光性能的变化情况及在空气中的稳定性。     

N‐σ versus π configuration in mono‐ and bis‐pyrrole and imidazole derivatives of alkaline earth metals

A theoretical study of the preferred N‐σ or π configuration of the mono‐ and bis‐pyrrole and imidazole derivatives of alkaline earth metals has been carried by means of DFT and ab initio methods, up to G2 computational level. The energetic results show that the beryllium derivatives prefer the N‐σ configuration while the calcium ones prefer the π one. In the case of magnesium, both configurations present similar stability. The calculated dissociation enthalpies correspond to the fact that the metallic atom is strongly bonded to the azoles in both configurations. The NBO analysis shows that the systems can be considered as formed by the azolates interacting with the charged metallic atom and thus the Natural Energy Decomposition Analysis (NEDA) indicates that the main attractive force is the electrostatic. Copyright © 2009 John Wiley & Sons, Ltd.     

新型添加剂对单晶硅表面金字塔形貌的影响

单晶硅表面微结构对晶体硅光电转换性能有非常重要的影响, 晶体硅表面微结构的调节技术一直是半导体、 太阳能电池领域研究的热点之一.利用碱液与单晶硅异向腐蚀特性的刻蚀技术, 在单晶硅表面可以获得布满金字塔的绒面, 但普通碱液刻蚀的绒面, 其金字塔大小、 形貌和分布随机性大, 不利于提高硅太阳电池的转换效率.在普通的碱腐蚀液中加入不同量的特种添加剂, 然后在相同的温度、 时间下刻蚀单晶硅表面, 通过观察样品表面SEM图, 发现在普通碱液中加入适量添加剂后刻蚀的单晶硅表面能形成均匀密集分布金字塔, 金字塔大小在2     

Spectrophotometric Study of Luminol in Dimethyl Sulfoxide–Potassium Hydroxide

The spectrophotometric study of luminol (LH₂) in dimethyl sulfoxide (DMSO), DMSO-water solutions, and alkaline DMSO and DMSO-water solutions has been done, focusing on the effect of the KOH additon on LH₂ absorption and fluorescence properties. The absorption spectra indicate an acid-base equilibrium, and the luminol dianion (L^2–) formation at 3 × 10^–4 – 2.4 × 10^–3 M KOH. The decrease of the fluorescence intensity and the variation of the excitation spectra of LH₂-DMSO-KOH solutions with KOH concentration have been similarly explained. The acid-base process is reversible. The addition of HCl to the solution with 3.0 × 10^–3 M KOH leads to an increase of the fluorescence intensity to its highest value, observed in pure DMSO. The addition of HCl to the LH₂-DMSO solution leads to the decrease of the fluorescence intensity as a result of the LH⁺ ₃ cation formation. In LH₂-DMSO-water, the fluorescence band is shifted from 405 nm to 424 nm and increased in the intensity. In the presence of KOH (in LH₂-DMSO-water-KOH solution) a new band appears, with the maximum at 485 nm and the band at 405 nm decreased. The changes in fluorescence lifetimes also evidence the different chemical species formed.     

Asymmetric conductivity of the Kondo effect in cold atomic systems

Motivated by recent theoretical and experimental advances in quantum simulations using alkaline earth(AE)atoms,we put forward a proposal to detect the Kondo physics in a cold atomic system.It has been demonstrated that the intrinsic spin-exchange interaction in AE atoms can be significantly enhanced near a confinement-induced resonance(CIR),which facilitates the simulation of Kondo physics.Since the Kondo effect appears only for antiferromagnetic coupling,we find that the conductivity of such system exhibits an asymmetry across a resonance of spin-exchange interaction.The asymmetric conductivity can serve as the smoking gun evidence for Kondo physics in the cold atom context.When an extra magnetic field ramps up,the spin-exchange process near Fermi surface is suppressed by Zee-man energy and the conductivity becomes more and more symmetric.Our results can be verified in the current experimental setup.     

电子俘获型薄膜材料的结构与光学性能

采用电子束沉积技术成功制务了以碱土金属硫化物为基质材料，稀土元素离子作为激活中心的输出红光的红外上转换及光存储薄膜材料ＣａＳ：Ｅｕ，Ｓｍ物相结构测试表明，基片温度和后退火晶化处理对薄膜的晶态有很大影响，在本实验的制备条件下，（２００）面的衍射蜂最强；加硫共蒸或通入少量Ｈ２Ｓ有助于改善ＣａＳ薄膜的化学计量比，光谱测试表明，薄膜材料的光学性能与粉末材料基本相同。     

Lattice energy and phase transition of alkaline earth chalcogenide

In this study, we have investigated the high-pressure structural phase transition of alkaline earth's chalcogenides within the framework of three-body potentials. We are considering short-range repulsive interactions up to the second nearest neighbors. The structural phase transition from the low-pressure NaCl (B1) to the high-pressure CsCl (B2) structure is estimated by Gibbs free energy calculations. The results are satisfactory and in agreement with the available experimental and other theoretical results.     

Effect of high hydrostatic pressure on enzyme activity in unpasteurized draft sake

ABSTRACT

Unpasteurized draft sake has a potentially high market value, due to its fresh flavor and fruity taste, compared with conventional thermal-pasteurized sake. However, the shelf life of draft sake is limited. To increase the shelf life of draft sake, it is necessary to suppress flavor and taste deterioration resulting from inactivation of enzymes produced by koji-mold. Draft sake was treated with high hydrostatic pressure (HHP) of 200 to 500?MPa at ?7 to 50°C to analyze the inactivation of α-amylases, glucose-forming enzymes, and acid carboxypeptidases. We found significant inactivation of enzymes produced by koji-mold in draft sake subjected to HHP treatment at both high and low temperature. However, HHP treatment at low temperature effectively inactivated enzymes while retaining the fresh flavor and fruity taste of draft sake.