Approximated Uncertainty Propagation of Correlated Independent Variables Using the Ordinary Least Squares Estimator.

For chemical measurements, calibration is typically conducted by regression analysis. In many cases, generalized approaches are required to account for a complex-structured variance-covariance matrix of (in)dependent variables. However, in the particular case of highly correlated independent variables, the ordinary least squares (OLS) method can play a rational role with an approximated propagation of uncertainties of the correlated independent variables into that of a calibrated value for a particular case in which standard deviation of fit residuals are close to the uncertainties along the ordinate of calibration data. This proposed method aids in bypassing an iterative solver for the minimization of the implicit form of the squared residuals. This further allows us to derive the explicit expression of budgeted uncertainties corresponding to a regression uncertainty, the measurement uncertainty of the calibration target, and correlated independent variables. Explicit analytical expressions for the calibrated value and associated uncertainties are given for straight-line and second-order polynomial fit models for the highly correlated independent variables.

Development of a Novel Leak-Free Constant-Pressure Cylinder for Certified Reference Materials of Liquid Hydrocarbon Mixtures.

Liquid hydrocarbon mixtures such as liquefied petroleum gas and liquefied natural gas are becoming integral parts of the world's energy system. Certified reference materials (CRMs) of liquid hydrocarbon mixtures are necessary to allow assessment of the accuracy and traceability of the compositions of such materials. A piston-type constant-pressure cylinder (PCPC) comprising chambers for a pressurizing gas (helium) and liquid (hydrocarbons) separated by a piston can be used to develop accurate and traceable liquid hydrocarbon mixture CRMs. The development of accurate CRMs relies on the maintenance of their composition. However, a PCPC might allow hydrocarbons to leak owing to the imperfect seal of the piston. In this study, a novel leak-free bellows-type constant-pressure cylinder (BCPC) is designed and evaluated by comparison with PCPCs. Liquid hydrocarbon mixtures consisting of ethane, propane, propene, isobutane, n-butane, 1-butene, and isopentane were prepared in both types of constant pressure cylinders and then monitored to check leakages between the gas and liquid chambers. Overall, notable leakage occurred from and into both chambers in the PCPCs, whereas no leakage occurred in the BCPCs in the three months after their gravimetric preparation. The BCPCs maintained no leakage even 10 months after their preparation, whereas the PCPCs showed significantly increasing leakage during the same period.

Fabrication of chemiluminescence sensor based on conducting polymer@SiO2/Nafion composite film.

Tris(2,2'-bipyridyl)ruthenium (II) (Ru(bpy)2+) electrogerated chemiluminescence (ECL) sensor was fabricated by immobilization of Ru(bpy)2+ complex on conducting polymer@SiO2/Nafion composite film on surface of glassy carbon electrode. The conducting polymer@SiO2 nanocomposites were prepared by coating polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) on the surface of the SiO2 sphere. The conducting polymer@SiO2 nanocomposite was characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and atomic force microscopy (AFM). The sensitivity and reproducibility of the prepared ECL sensor to tripropylamine (TPA) was evaluated. As a result, the PPy@SiO2 composite electrode exhibited high sensitivity and good reproducibility compared to that obtained with PANI@SiO2 and PTh@SiO2 composite electrodes because of the strong interaction between PPy@SiO2 and Ru(bpy)2+ complex.

Preparation of Pt-Ru@ polypyrrole-MWNT catalysts by gamma-irradiation and chemical reduction and their adsorption capacity for CO.

With the objective to prepare electrocatalysts with high efficiency, the Pt-Ru@PPy-MWNT catalysts were prepared by different approaches. First, the polypyrrole (PPy) as anchoring materials was coated on the surface of multi walled carbon nanotubes (MWNT) by in situ polymerization. Subsequently, Pt-Ru nanoparticles were deposited onto PPy-MWNT composite by different methods like the reduction of metal ions by gamma-irradiation and chemical reduction using formaldehyde as reducing agent assisted with stirring of magnetic bar, and assisted with microwave irradiation, and assisted with ultrasonic irradiation, in order to prepare electrocatalyst for fuel cell. The catalytic efficiency of Pt-Ru@PPy-MWNT catalyst was examined for CO stripping.

Fabrication of functional poly(thiophene) electrode for biosensors.

Three-type polymer electrodes such as poly(Th), poly(Th-AP) and poly(Th-AP-TAA) were fabricated, respectively, by electro-oxidative polymerization of thiophene (Th), mixture of Th and 2-aminophenol (AP), and mixture of Th, AP and 3-thiopheneacetic acid (TAA) on the surface of indium tin oxide (ITO) glass by cyclic voltammetry (CV). The polymer electrodes were electrodeposited by cycling the potential between -1.0 and +2.5 V in acetonitrile containing 50 mM tetrabutylammoniumhexafluorophosphate (TBAF(6)P). The surface morphology of polymer electrodes was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis. The surface morphology of the poly(Th) showed typical roughness and fractal-like growth patterns, and the morphologies of poly(Th-AP) and poly(Th-AP-TAA) were dramatically changed. The water contact angle at the poly(Th-AP-TAA) (23 degrees) is lower in comparison to poly(Th) (47 degrees ). The functional groups (-OH) and carboxylic acid (-COOH) group play an important role. Horseradish peroxidase was loaded onto poly(Th-AP-TAA) surface and used to test the sensing of H(2)O(2).

Horseradish peroxidase immobilized on poly(thiophene-2-aminophenol-3-thiopheneacetic acid) film electrode with Au nanoparticle-fabrication and evaluation as hydrogen peroxide sensor.

Enzyme immobilized electrode was fabricated by two methods. In one of the methods, gold-nanoparticles (Au-NPs) prepared by gamma-irradiation were loaded into the copolymer film and horseradish peroxidase (HRP) was immobilized into the Au-NPs loaded copolymer film through physical entrapment. In the other method, the Au-NPs was prepared by electrochemical reduction of Au ions on the surface of poly(Th-AP-TAA) and HRP was immobilized into the Au-NPs. The enzyme immobilized electrodes were tested for electrocatalytic activities towards sensing of H2O2.

Anatomical Study of Cavernous Sinus

Fifty four preparations of the cavernous sinus from twenty seven cadavers were studied in detail under microscopic magnification, with special attention to nerves and arteries related to the wall of the sinus. Significant findings were: 1) Three types of relationship between the nerves and arteries in relation to the wall of the sinus were found. Type I: The nerves III, IV and V-1 were embedded in the lateral wall, and the internal carotid artery(I.C.A.) and nerve IV passed through the cavity of the sinus(26 specimens, 48%), Type II: The cavity of the sinus was divided into two compartments by a septum close to the lateral wall, with nerves VI and V-I located within the septum(18 specimens, 33%), Type III: Anatomy was similar to the type I, except that the I.C.A. was included in the medial or lateral wall(10 specimens, 19%). 2) Arterial variations branching from the intracavernous portion of the I.C.A. were classified into four types. Type I: Meningohypophyseal trunk arising from I.C.A.(28 specimens). Type II: Dorsal meningeal artery from I.C.A.(10 specimens). Type III:Tentorial artery from I.C.A.(4 specimens). Type IV: Meningohypophyseal trunk from I.C.A. in addition, the artery of inferior cavernous sinus(12 specimens). 3) The main three brahcnes of the intracavernous portion of the I.C.A. were the meningohypophyseal artery, which was presented presented in 100% of our specimens, the artery of inferior cavernous sinus(78%), and McConnell's capsular artery(43%). Intracavernous origin of the ophthalmic artery were observed in four specimens(8%). 4) The surgical triangle spaces were found to be present in all our specimens, which were formed by the superior margin of it with the lower margin of nerve IV and by the inferior margin with the upper margin of nerve V-I.

Xanthoma in the lat. Ventricle Combined with Arachnoid Cyst in Left Sylvian Fissure, Aneurysm of the MCA, and Osteoma in the Skull: Case Report

The authors introduce a extremely rare case of xanthoma in the lateral ventricle which combined with the arachnoid cyst, aneurysm, and osteoma. This 11-year-old girl has been suffered the Rt. Sided motor weakness, the slurred speech and seizures before 1 year. The simple skull AP view showed the elevation of left sphenoidal ridge bulging temporal bone(Lt.), the localized sclerotic margin and centrally osteolytic change in the Lt. frontal bone. Brain computed tomogram revealed a relatively well circumscribed, moderately enhanced mass in the trigone of the left lateral ventricle accompanying with irregular low density in the left temporal lobe. At left carotid angiogram, multiple aneurysm of the Genu of the middle cerebral artery was found without spasm of adjacent vessels. The patient had operation for removal of the tumor, Arachnoid cyst and for wraping of the Aneurysm. The pedunculated reddish white mass was completely removed. The patient had improvement and discharged without another neurologic deficits. The motor mass was the Xanthoma.