NORDSIECK FORMS OF STIFFLY-STABLE ADAMS-TYPE CYCLIC METHODS THAT ARE INSENSITIVE TO STEP-SIZE CHANGES

In this paper we determine a matrix S and a vector l for stiffly-stable Adams-type cyclic methods that are insensitive to step size changes by using the definition of equivalent methods, (see, e.g. [l]), in the Nordsieck notation. The elements S and l, written in a parametric form, permit us to represent in Nordsieck form the methods that were constructed in [7] and the new methods that satisfy the above properties.

Serial Mitsuda tests for identification of reactional tuberculoid and reactional borderline leprosy forms

The authors studied the Mitsuda reaction in 37 leprosy patients (18 reactional tuberculoid, 19 reactional borderline cases) and compared the results with clinical findings, histopathology and bacilloscopy. Evaluation of the Mitsuda reaction was carried out on days 30, 60, 90 and 120. Most of the reactional tuberculoid patients showed a Mitsuda reaction of +++ in opposition to the reactional borderline patients who showed only +. Bacilloscopic analysis revealed that in 75% of the reactional tuberculoid cases there were rare or no bacilli; bacilli were present in 95% of the reactional borderline cases. The authors conclude that reactional tuberculoid cases have a greater ability to clear bacilli than reactional borderline cases, and that the Mitsuda reaction is a useful tool for the differentiation between these two types of leprosy.

New crystal forms of Diocleinae lectins in the presence of different dimannosides

Studying the interactions between lectins and sugars is important in order to explain the differences observed in the biological activities presented by the highly similar proteins of the Diocleinae subtribe. Here, the crystallization and preliminary X--ray data of Canavalia gladiata lectin (CGL) and C. maritima lectin (CML) complexed with Man(alpha 1-2)Man(alpha 1)OMe, Man(alpha 1-3)Man(alpha 1)OMe and Man(alpha 1-4)Man(alpha 1)OMe in two crystal forms [the complexes with Man(alpha 1-3)Man(alpha 1)OMe and Man(alpha 1-4)Man(alpha 1)OMe crystallized in space group P3(2) and those with Man(alpha 1-2)Man(alpha 1)OMe crystallized in space group I222], which differed from those of the native proteins (P2(1)2(1)2 for CML and C222 for CGL), are reported. The crystal complexes of ConA-like lectins with Man(alpha 1-4)Man(alpha 1)OMe are reported here for the first time.

Anti-neutrophil cytoplasmic antibodies (ANCA) in the clinical forms of leprosy

Anti-neutrophil cytoplasmic antibodies (ANCA) are autoantibodies against enzymes present in primary granules of neutrophils and lysosomes of monocytes detected in systemic vasculitis and in other diseases, including infections, ANCA are markers of active Wegener granulomatosis, which presents some anatomo-pathologic and immune response features similar to those of leprosy. Thus, we raised the hypothesis that ANCA may be present in leprosy as markers specifically linked to the presence of vasculitis. The aim of this study was to determine the presence of ANCA in leprosy and its correlation with the clinical forms of the disease. Sera from 60 normal individuals and from 59 patients with different clinical forms of leprosy were studied. The patients were also allocated into reactional and nonreactional groups. By indirect immunofluorescence, ANCA were positive, an atypical pattern A-ANCA, in 28.8% of the patient sera. A-ANCA predominated, although not significantly (p >0,05), in the reactional groups (37.9% vs 20.0%), and in those at the lepromatous pole (41.6% vs 20.0%). There was no correlation between ANCA positivity and either disease duration, disease activity, or therapeutic regimen (p >0.05), An interesting finding was the correlation between ANCA and gender: 94.1% of ANCA-positive patients were males (p <0.01), a feature that so far has not been reported in ANCA-related diseases and for which there is no explanation at the moment. By ELISA, the sera of the lepromatous leprosy patients did not show activity against either PR3, MPO, HLE, the most common ANCA antigens. Because A-ANCA are nonspecific, this finding requires further investigation for the determination of the responsible antigen(s), in conclusion, A-ANCA are present in 28.8% of leprosy patients but are not related to vasculitis in the erythema nodosum leprosum reaction and are not a marker of a specific clinical form.

Dynamic viscosity of binary and ternary mixtures containing poly(ethylene glycol), potassium phosphate, and water

Dynamic viscosity of binary mixtures of poly(ethylene glycol) molar mass 1500 da + water, potassium phosphate + water, and ternary mixtures of poly(ethylene glycol) molar mass 1500 da + potassium phosphate + water were determined at 303.15 K Binary and ternary mixture viscosities showed a direct logarithm-type relation with the increase of poly(ethylene glycol) and potassium phosphate contents. The models used for viscosity correlation gave a good fit to the experimental data.

Mineralogy and forms of potassium in red yellow latosol of a guava (Psidium guajava) tree orchard

A trial was conducted during 1994-95 to study the effect of potassium fertilization on a guava (Psidium guajava L.) culture for 3 years. The control plots (without K) showed fruit production and potassium exportation that did not agree with the levels obtained by chemical analysis of the soil. Physical, chemical, mineralogic and morphologic analyses were performed on the red yellow latosol to identify minerals able to supply potassium, with emphasis on the fact that guava trees have a considerably widespread root system. The results obtained confirmed the presence of minerals in this soil that can supply potassium to the trees through weathering. Feldspars were identified in the silt fraction and micas in the clay fraction by X-ray diffractometry. The determination of total potassium revealed that the silt fraction of the soil had the largest absolute amounts of potassium, followed by clay. However, in view of its greater content, clay was the fraction that contributed most to the total amounts of potassium detected.

Relating propelinear and binary G-linear codes

In this paper we establish the connections between two different extensions of Z(4)-linearity for binary Hamming spaces, We present both notions - propelinearity and G-linearity - in the context of isometries and group actions, taking the viewpoint of geometrically uniform codes extended to discrete spaces. We show a double inclusion relation: binary G-linear codes are propelinear codes, and translation-invariant propelinear codes are G-linear codes. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Voltammetric assay of albendazole in pharmaceutical dosage forms

A simple, rapid inexpensive voltammetric method have been developed for the quantitative determination of albendazole (ABZ) as the pure assay, by direct dissolution of commercial tablets in HCl solutions. Studies with linear sweep (LSV), square-wave (SWV) and differential pulse voltammetry (DPV) were carried out ABZ in aqueous medium at a glassy carbon electrode. A well defined irreversible oxidation peak current was obtained at 1,00V vs. SCE. The method permits a precise quantitative determination of ABZ using the standard addition method. The detection limits for the three voltammetric techniques were found to be 3.0 x 10(-5) M (LSV), 6.2 x 10(-5) M (SWV) and 4.0 x 10(-5) M (DPV).

Molecular model for the binary complex of uropepsin and pepstatin

The three-dimensional structure of human uropepsin complexed with pepstatin has been modelled using human pepsin as a template. Uropepsin is an aspartic proteinase from the urine, produced in the form of pepsinogen A in the gastric mucosa. The structure is bilobal, consisting of two predominantly beta -sheet lobes which, as observed in other aspartic proteinases, are related by a pseudo twofold axis. A structural comparison between binary complexes of pepsin:pepstatin and uropepsin:pepstatin is discussed. (C) 2001 Academic Press.

Environmental coordination chemistry: Binary systems comprising some bivalent cations and monocarboxylates in aqueous solution. Ionic medium effects on equilibrium constants

The molar single activity coefficients associated with propionate ion (Pr) have been determined at 25 degrees C and ionic strengths comprised between 0.300 and 3.00 M, adjusted with NaClO4, as background electrolyte. The investigation was carried out potentiometrically by using a second class Hg/Hg2Pr2 electrode. It was found that the dependence of propionate activity coefficients as a function of ionic strength (I) can be assessed through the following empirical equation: log y(Pr) = -0.185 I-3/2 + 0.104 I-2. Next, simple equations relating stoichiometric protonation constants of several monocarboxylates and formation constants associated with 1:1 complexes involving some bivalent cations and selected monocarboxylates, in aqueous solution, at 25 degrees C, as a function of ionic strength were derived, allowing the interconversion of parameters from one ionic strength to another, up to I = 3.00 M. In addition, thermodynamic formation constants as well as parameters associated with activity coefficients of the complex species in the equilibria are estimated. The body of results shows that the proposed calculation procedure is very consistent with critically selected experimental data.

Ionic medium effects on equilibrium constants .2. Binary systems comprising some bivalent cations and monocarboxylates in aqueous solution

Simple equations were derived relating stoichiometric protonation constants of several monocarboxylates and formation constants associated with 1:1 complexes involving some bivalent cations and selected monocarboxylates, in aqueous sodium perchlorate media, at 25 degrees C, as a function of ionic strength (I), allowing the interconversion of parameters from one ionic strength to another, up to I = 3.00 M. In addition, thermodynamic formation constants as well as activity coefficients of the species involved in the equilibria were estimated. The results show that the proposed calculation procedure is very consistent with critically selected experimental data.

Synthesis and properties of branched polyethylene/high-density polyethylene blends using a homogeneous binary catalyst system composed of early and late transition metal complexes

Branched polyethylene/high-density polyethylene blends (BPE/HDPE) with a wide range of molecular weights, melt flow indexes (MFI), and intrinsic viscosity were prepared using the homogeneous binary catalyst system composed by Ni(alpha-diimine)Cl-2 (1) (alpha-diimine = 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine) and {Tp(Ms*)} TiCl3 (2) (Tp(Ms*)=hydridobis(3-mesitylpyrazol-1-yl)(5-mesityl-pyrazol-1-yl)) activated with MAO and/or TIBA in hexane at two different polymerization temperatures (30 and 55 degreesC) and by varying the nickel loading molar fraction (x(Ni)). At all Temperatures, a non-linear correlation between the x(Ni) and the productivity was observed, suggesting the occurrence of a synergistic effect between the nickel and the titanium catalyst precursors, which is more pronounced at 55 degreesC. The molecular weight of the BPE/HDPE blends considerably decreases with increasing Al/M molar ratio. The melt flow indexes (MFI) and intrinsic viscosities (eta) are strongly affected by x(Ni), but the melting temperatures are nearly constant, 132 +/- 3 degreesC. Dynamic mechanical thermal analysis (DMTA) shows the formation of different polymeric materials where the stiffness vanes according, to the x(Ni) and temperature used in the polymerization reaction. The surface morphology of the BPE/HDPE blends studied by scanning electron microscopy (SEM) revealed a low miscibility between the PE phases resulting in the formation of a sandwich structure after etching with o-xylene.