Application of autoregressive modelling for the analysis of clinical and other biological data

This paper deals with the application of autoregressive (AR) modelling for the analysis of biological data including clinical laboratory data. In the first part of the paper, we discuss the necessity of feedback analysis in the field of biochemistry. In order to enable this, relative power contribution analysis was introduced. Next, we utilized the two types of impulse response curves of the open and closed loop systems for elucidating the structure of the metabolic networks under study. Time series data obtained from 31 chronic hemodialysis patients observed for periods of 3 to 7 years were analyzed by these procedures. The results of the analysis were rather uniform among the patients and suggested the consistency of this approach in identifying the dynamical system of individual patients. An example of data set is included in the paper.     

A convenient method for synthesis of enantiomerically enriched methylphenidate from N-methoxycarbonylpiperidine

[formula: see text] This report describes a new method to prepare optically active methylphenidate starting from piperidine. The method consists of a transformation of N-methoxycarbonylpiperidine to the corresponding alpha-methoxylated carbamate I by utilizing electrochemical oxidation followed by the coupling reaction with optically active Evans imides II to produce optically active methylphenidate derivatives III with high stereoselectivities, threo-(2R,2'R)-Methylphenidate (IV; Ar = Ph; Ritalin) was easily prepared from III in three steps.     

Oxidation of alcohols by active species generated by electrochemical oxidation of organosulfur compounds

Oxidation of secondary alcohols to ketones was accomplished by an indirect electrochemical method utilizing thioanisole as a catalytic electron carrier.     

Transformation of biodegradable polyesters into cyclic oligomers under continuous flow using an enzyme-packed column

The enzymatic degradation of typical chemically synthesized biodegradable plastics, such as poly(butylene adipate) and poly(epsilon-caprolactone), to a repolymerizable cyclic oligomer under continuous flow using an enzyme column was studied, directed towards green chemical recycling. It was confirmed that both polymers were quantitatively transformed into the corresponding cyclic oligomers by passage through the column packed with immobilized lipase from Candida antarctica (Novozym 435) at 40 degrees C using a toluene solution. Compared to the batch treatment in a flask, a short reaction time and a low reaction temperature occurred for complete transformations of the polyesters by continuous flow through the enzyme column. The degradation activity of the enzyme column was maintained for at least six months at 40 degrees C. Conceptual scheme of the continuous degradation equipment using the enzyme column.     

Chemo- and stereoselective monobenzoylation of 1,2-diols catalyzed by organotin compounds

A new facile method for monoacylation of diols has been developed. A variety of cyclic and acyclic diols, in particular 1,2-diols, were selectively monobenzoylated in good yields by the reaction with benzoyl chloride in the presence of a catalytic amount of dimethyltin dichloride and inorganic bases such as potassium carbonate. Furthermore, the method was successfully applied to a kinetic resolution of racemic 1-phenyl-1,2-ethanediol using a chiral organotin catalyst. The ee was dependent on the kind of base, water as an additive, and the reaction temperature.     

Microwave spectrum of CIS chlorine nitrite,CIONO

The metastable intermediate product, CIONO, which is formed from gaseous CINO and Cl₂O at about 203 K, has been detected by microwave spectroscopy. The rotational constants and the inertial defects for the ³⁵Cl and ³⁷Cl species establish that the observed spectrum is that of planar cis CIONO.     

Structure and electric conductivity of vapor deposition polymerization products of cyanoacetylene

Cyanoacetylene can be polymerized from the vapor state onto an inactive surface of substrate at a temperature as low as 200°C. The polymerization first occurs by way of the carbon–carbon triple bond. The reaction product obtained at 1000°C contains nitrogen at a concentration as high as 13.7%. At least some of this nitrogen is in naphtiridine ring or rings similar to it. The product obtained at 400°C is amorphous, while the product obtained at 1000°C has at least partly graphite-like crystalline structures with an apparent crystallite size (L_c) of about 17 Å. The electric conductivities of the products obtained at 400, 700, and 1000°C are 7.7 × 10^?2, 91, and 1600 S/cm, respectively. These values are extremely high compared to the pyrolized PAN treated at the same temperature. Electric conductivity of the product obtained at 400°C is well explained by the variable range hopping model in 3-dimensional amorphous materials. With the products obtained at the higher temperatures, conductivity cannot be accounted for by the hopping model. This is probably due to the development of graphite-like structure.