Muscle oxygenation measurement in humans by noninvasive optical spectroscopy and Locally Weighted Regression

We have developed a method to make real-time, continuous, noninvasive measurements of muscle oxygenation (Mox) from the surface of the skin. A key development was measurement in both the visible and near infrared (NIR) regions. Measurement of both oxygenated and deoxygenated myoglobin and hemoglobin resulted in a more accurate measurement of Mox than could be achieved with measurement of only the deoxygenated components, as in traditional near-infrared spectroscopy (NIRS). Using the second derivative with respect to wavelength reduced the effects of scattering on the spectra and also made oxygenated and deoxygenated forms more distinguishable from each other. Selecting spectral bands where oxygenated and deoxygenated forms absorb filtered out noise and spectral features unrelated to Mox. NIR and visible bands were scaled relative to each other in order to correct for errors introduced by normalization. Multivariate Curve Resolution (MCR) was used to estimate Mox from spectra within each data set collected from healthy subjects. A Locally Weighted Regression (LWR) model was built from calibration set spectra and associated Mox values from 20 subjects using 2562 spectra. LWR and Partial Least Squares (PLS) allow accurate measurement of Mox despite variations in skin pigment or fat layer thickness in different subjects. The method estimated Mox in five healthy subjects with an RMSE of 5.4%.     

On the extendability of certain semi-Cayley graphs of finite abelian groups

A connected graph Γ with at least 2n+2 vertices is said to be n-extendable if every matching of size n in Γ can be extended to a perfect matching. The aim of this paper is to study the 1-extendability and 2-extendability of certain semi-Cayley graphs of finite abelian groups, and the classification of connected 2-extendable semi-Cayley graphs of finite abelian groups is given. Thus the 1-extendability and 2-extendability of Cayley graphs of non-abelian groups which can be realized as such semi-Cayley graphs of abelian groups can be deduced. In particular, the 1-extendability and 2-extendability of connected Cayley graphs of generalized dicyclic groups and generalized dihedral groups are characterized.     

苯乙烯基噻吩单体及对应的聚脲烷的合成 及其非线性光学性能

一种新型的反式-7-［4-N,N-二(β-羟基乙基胺基苯)］-3,5-二硝基乙烯基-噻吩（HBDT）单体分子及对应的预聚物和聚脲烷被合成和表征.由于噻吩环的电子去局域化能量低于苯环,在受授有机共轭化合物中噻吩环比苯环表现出更有效的共轭和更高的非线性,同时也能使目标分子保持好的光、热稳定性.该单体分子及其对应的聚脲烷在普通有机溶剂中具有良好的可溶性,聚脲烷膜具有好的热稳定性.制备了高质量的聚脲烷膜并进行了电晕极化.单体在甲醇中的紫外可见吸收峰（530nm）与对应未经电晕极化聚脲烷膜的吸收峰基本上没有改变.通过溶剂变色法及简并四波混频（DFWM）法测试了单体的二阶和三阶非线性极化率,其β     

RT二维CT扫描的精确重建

基于多个旋转中心的旋转/平移扫描方法(RT扫描)可利用近轴X射线对大型回转试件进行二维CT检测。同传统的二代CT平移/旋转扫描(TR)相比,RT二维CT扫描的扫描时间是TR二维CT扫描时间的1/3。但由RT二维CT扫描插值全局重建的图像,在物体内部,其特征边缘有明显的伪影。采用一种精确的分区域重建方法可消除这种伪影。计算机仿真验证了这种重建算法的可行性。     

KTP晶体的电光研究进展

本文简述了KTP晶体的电光性能并与KD*P、LN晶体进行了比较。概括了KTP晶体电光器件研究的主要进展。对水热法生长的KTP晶体和熔剂法生长的KTP晶体在电光应用中的优缺点进行了分析。最后介绍了熔剂法生长的低电导率KTP晶体在电光领域的应用研究。     

Tetrazole derivatives and matrices as novel cobalamin coordinating compounds

Cobalamin (Cbl, vitamin B₁₂) consists of two moieties: (i) the corrin ring with the central Co-ion in the oxidation states Co^3+/2+/1+ and (ii) the nucleotide side chain. The lower position of the ring is typically occupied by the nucleotide base (Bzm), whereas the upper surface coordinates exchangeable ligands. We have found that amino-tetrazole can coordinate to H₂O · Cbl (Co³⁺) with K_d = 10⁻⁵-10⁻⁶ M. A specific group (presumably tetrazole, TZ) can be easily created in CNBr-activated Sepharose by treatment with . The prepared matrix (STZ) contained ≈10 mM of the active groups, which bound H₂O · corrinoids with K_d = 10⁻⁵-10⁻⁶ M. Stability of STZ-Cbl bonds gradually increased and reached K_d = 10⁻⁷ M over 10-20 h (20 °C, pH 6-7). This effect can be ascribed to partial displacement of Bzm and coordination of TZ to the lower position. The binding was most efficient at pH 4-7 and low ionic strength, yet, noticeable adsorption took place even at extreme conditions, pH 1-9 and I = 0-2 M. Reduced corrins (Co²⁺) also exhibited high affinity for STZ. The bound ligands could be eluted as H₂O · Cbl (pH 0), HO · Cbl (pH 14) or diCN · Cbl (pH 9-12, CN⁻). The adsorbent is applicable for one-step purification of corrins from a crude extract; separation of aquo- and diaquo-forms; specific capturing of H₂O · Cbl from a mixture containing organo-Cbls or protein-bound Cbl, analysis of peptide-Cbl dissociation kinetics, etc.     

Carbon and proton magnetic resonance studies on the sites of Mn2+ and Ni2+ ion binding with thiamin and thiamin pyrophosphate and on the solution conformation of the coenzyme

Carbon magnetic resonance was employed to determine the Mn²⁺ and Ni²⁺ binding sites on thiamin and thiamin pyrophosphate and to help elucidate the solution conformation of the latter with Mn²⁺. In comparison with previous proton magnetic resonance studies, the results here presented elucidate direct binding to thiamin even without the presence of the pyrophosphate. In thiamin Mn²⁺ is bound to both the pyrimidine ring and to the oxygen of the β-hydroxyethyl chain, albeit more weakly to the former, Ni²⁺, on the other hand is indicated in binding to the pyrimidine ring only. From observation of water relaxation data, potentiometric determination of the pyrimidinium pK_a with metal ions added and carbon magnetic resonance (competition of thiamin and thiamin pyrophosphate for Mn²⁺) we have very strong evidence to indicate that Mn²⁺ is separated from the pyrimidine ring by a solvent molecule. We were able to estimate association constant between the pyrimidine and Mn²⁺ (50 M^?1) and OH and Mn²⁺ (100 M^?1) in thiamin.In thiamin pyrophosphate both Mn²⁺ and Ni²⁺ much prefer the pyrophosphate as binding sites and at least in the former an inner sphere complex is indicated. Also with Mn²⁺ present the dimethylene pyrophosphate is folded back onto the thiazolium ring according to analysis of proton broadening data and relaxation mechanisms.     

Modeling the thermodynamic and transport properties of decahydronaphthalene/propane mixtures: Phase equilibria, density, and viscosity

The density and viscosity of propane mixed with 66/34 trans/cis-decahydronaphthalene were measured over a wide range of temperatures (323-423 K), pressures (2.5-208 bar), and compositions (0-65 mol% propane). For conditions giving two phases, the composition of the dense phase was measured in addition to the density and viscosity. The modified Sanchez-Lacombe Equation of State (MSLEOS) was used with a single linearly temperature-dependent pseudo-binary interaction parameter to correlate the phase compositions and densities. The compositions and densities of the mixtures were captured well with absolute average deviations between the model and the data of 5.3% and 2.3%, respectively. The mixture viscosities were computed from a free volume model (FVM) by using a single constant binary interaction parameter. Density predictions from the MSLEOS were used as input mixture density values required for the FVM. The FVM was found to correlate well with the mixture viscosity data with an absolute average deviation between the model and the data of 5.7%.     

The preparation,characterization and reactivity of the cyclometallosilane,cyclo-1,1-di-h5-cyclopentadienyltitana-2,2,3,3,4,4,5,5,-octaphenylpentasilane, (h5-C5H5)2TiSi(C6H5)2[Si(C6H5)2]2Si(C6H5)2

Titanium has been incorporated into a catenated silicon ring by means of the salt elimination reaction of dichlorodi-h⁵-cyclopentadienyltitanium(IV), (I), with 1,4-dilithiooctaphenyltetrasilane, Li₂Si₄(C₆H₅)₈, to yield the title compound (II). II was characterized as a cyclometallopolysilane by means of elemental analyses, base catalyzed hydrolyses, molecular weight determination, infrared and ¹H NMR spectroscopy. Electronic spectral data and electrochemical data are also discussed and support the formulation of II as a disubstituted (h⁵-C₅H₅)₂Ti^IV derivative. The reactivity of II, with CHCl₃, is described in terms of a radical decomposition pathway.