Magnetically modified microbial cells： A new type of magnetic adsorbents

Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these cells enables to prepare magnetic adsorbents that can be easily manipulated in difficult-to-handle samples, such as suspensions, in the presence of external magnetic field. In this review, typical examples of magnetic modifications of microbial cells are presented, as well as their possible applications for the separation of organic xenobiotics and heavy metal ions.     

Fluctuations,effective learnability and metastability in analysis

This paper discusses what kind of quantitative information one can extract under which circumstances from proofs of convergence statements in analysis. We show that from proofs using only a limited amount of the law-of-excluded-middle, one can extract functionals (B,L)$(B,L)$, where L   is a learning procedure for a rate of convergence which succeeds after at most B(a)$B(a)$-many mind changes. This (B,L)$(B,L)$-learnability provides quantitative information strictly in between a full rate of convergence (obtainable in general only from semi-constructive proofs) and a rate of metastability in the sense of Tao (extractable also from classical proofs). In fact, it corresponds to rates of metastability of a particular simple form. Moreover, if a certain gap condition is satisfied, then B and L yield a bound on the number of possible fluctuations. We explain recent applications of proof mining to ergodic theory in terms of these results.     

Magnetic particles–based biosensor for biogenic amines using an optical oxygen sensor as a transducer

We have developed a fibre optic biosensor with incorporated magnetic microparticles for the determination of biogenic amines. The enzyme diamine oxidase from Pisum sativum was immobilized either on chitosan-coated magnetic microparticles or on commercial microbeads modified with a ferrofluid. Both the immobilized enzyme and the ruthenium complex were incorporated into a UV-cured inorganic–organic polymer composite and deposited on a lens that was connected, by optical fibres, to an electro-optical detector. The enzyme catalyzes the oxidation of amines under consumption of oxygen. The latter was determined by measuring the quenched fluorescence lifetime of the ruthenium complex. The limits of detection for the biogenic amines putrescine and cadaverine are 25–30 μmol?L^?1, and responses are linear up to a concentration of 1 mmol L^?1.

库仑加线性位基态解析解

应用新发展的单一轨迹积分方法求解库仑加线性位的基态量子波函数,得到基态能量和波函数的一般解析表达式,并讨论了解的收敛性.应用此方法讨论了重夸克偶素系统.     

Evidence for direct impact damage in metamict titanite CaTiSiO?

We have measured the dose dependence of the degree of amorphization of titanite, CaTiSiO(5). Titanite is an often metamict mineral which has been considered as a matrix for the encapsulation of radiogenic waste, such as Pu. The amorphous fraction p of geologically irradiated samples (ages between 0.3 and 1 Ga) follows p = 1 - exp(-B(a)D) where D is the total dose and the characteristic amorphization mass is B(a) = 2.7(3) × 10(-19) g. Amorphization follows the direct impact mechanism where each α-decay leads to a recoil of the radiogenic atoms (mostly Th and U), which then, in turn, displaces some 5000 atoms of the titanite matrix. The amorphization behaviour is almost identical with that of zircon, ZrSiO(4), which has a similar molecular mass. While the recrystallization mechanism and elastic behaviour of the two minerals are very different, we do not find significant differences for the amorphization mechanism. Our samples have undergone little reheating over their geological history, since heating over 800 K would lead to rapid recrystallization for which we have found no evidence.     

Superconductivity in the Einstein solid V Al(10.1)

We used magnetic susceptibility, resistivity and heat capacity measurements to characterize the superconducting state in the Einstein solid V Al(10.1). We find that V Al(10.1) is a weak-coupling, type-II superconductor with T(c)?=?1.53?K and an upper critical field of H(c2)(0)?=?800?Oe. The heat capacity data in the range 0.07?K?相似文献   

Determination of trimecaine metabolites in blood plasma by capillary isotachophoresis

A method is proposed for the determination of trimecaine (diethylglycylmesidide) and its de-ethylated metabolites (monoethylglycylmesidide and glycylmesidide) in blood plasma by capillary isotachophoresis. The deproteinated plasma is extracted into chloroform after alkalinization and the total solids in the organic layer are dissolved in acidified 25% 2-propanol. Subsequent isotachophoretic analysis is performed in an operational system consisting of potassium acetate buffer (pH 4.75) as the leading and beta-alanine as the terminating electrolyte. The order of the zones corresponds to the molecular weights of the separated compounds. The recovery of all substances of interest is 55% and the limit of determination is 0.05 micrograms of each substance in 1 ml of plasma.     

Composition dependence of the elastic constants of β-phase and (α + β)-phase PdHx

We have measured the composition and temperature dependence of the shear moduli C′ and C₄₄ for two-phase (α + β)- and single-phase β-PdH_x. In the two-phase region, the α- and β-phases are coherent. Here, the composition dependence of C₄₄ and C′ deviate negatively from a Vegard-type volume average. We attribute the deviations to two effects: (1) the partly in-series arrangement of the precipitate and matrix phases, relative to the externally applied stress, and (2) thermally activated anelastic relaxations involving the rapid motion of H interstitial atoms, leading to slight changes in the shape of coherent precipitates. The first effect is present for both C′ and C₄₄ and is temperature-independent, whereas the second is present only for C′ and is strongly temperature-dependent.     

Evidence that amorphous water below 160 K is not a fragile liquid

We have examined transport mechanisms in amorphous solid water (ASW) by studying thermal desorption of layered nanoscale films of CCl4 and labeled ASW. The interlayer mixing observed near T approximately 150-160 K is inconsistent with a mechanism involving diffusion through a dense phase. Instead, intermixing occurs via vapor-phase transport through an interconnected porous network created within the film during crystallization. As a consequence, the self-diffusivity of ASW is significantly smaller than previously thought, indicating that water undergoes either a glass transition or a fragile-to-strong transition at a temperature above 160 K.