Psoriatic arthritis: case report of acute HLA-B27 positive polyarthritis preceding the onset of typical skin changes

Psoriasis usually occurs many years before development of arthritis. This is a case report of a patient with acute polyarthritis affecting both peripheral joints and the left sacroiliac joint, preceding the appearance of typical skin manifestations for almost two months. A 44-year-old male mechanic was admitted to our institution for acute additive polyarthritis. Inflammatory synovitis primarily affected large peripheral joints (knees, ankles) in an asymmetrical pattern, with a concomitant development of unilateral sacroiliitis and later with asymmetrical involvement of several proximal and distal interphalangeal joints of the hands and feet. There were also signs of enthesopathy of the right heel. Arthritis was not proceeded by infection of the lower genital or gastrointestinal tract or serological and bacteriological evidences of streptococcal or HIV infection. Laboratory findings showed an erythrocyte sedimentation rate (92 in the first hour), positive histocompatibility antigen HLA-B27 and an increased level of acute phase reactants. Almost two months after affecting the locomotor system a typical psoriatic rash developed, first affecting the scalp and then spreading over the trunk and extremities. It was accompanied by severe onychodystrophy. The patient underwent intensive treatment with methylprednisolone (1.5 mg/kg) and cyclosporine A with significant results.     

Application of HLA class II polymorphism analysis to the study of the population structure of the Island of Krk, Croatia

The population structure of the northern Adriatic island of Krk, Croatia, was studied using PCR methodology and nonradioactive oligonucleotide hybridization for the analysis of HLA-DRB1, DRB3, DRB4, DRB5, DQA1, and DQB1 polymorphisms. Allele frequencies, genetic kinship (R), and genetic distances (E2) were computed, and correlations between distance (genetic, linguistic, geographic) and kinship (migration) matrices were examined. The results, reflecting past (micro-) evolutionary processes, indicate that ethnohistorical and sociocultural events rather than geographic distances are the primary determinants of today's population structure of the island.     

Combustion kinetics of coal dust

A method for determining parameters that are important for the combustion kinetics of coal dust is developed. Values of these parameters for six types of lignite are obtained from experimental results on combustion of coal dust in a laboratory furnace.Institute of Nuclear Research Vina, Laboratory of Heat Engineering and Power, Belgrade, Yugoslavia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 2, pp. 258–262, March–April, 1995.     

Canonical form of para‐Hermitian pencils,generalized spectral factorization,and optimal control over frequency region

We generalize the J‐spectral factorization of para‐Hermitian proper rational matrix in the case when it has no constant inertia on the imaginary axis. This result and the presented numerical algorithm are based on a canonical form of para‐Hermitian matrix pencils. We apply the new spectral factorization to the optimal control of the proper plant by dynamic measurement feedback over a frequency region. Copyright © 2012 John Wiley & Sons, Ltd.     

Oxygen reduction reaction on spontaneously and potentiodynamically formed Au/TiO2 composite surfaces

From aqueous solutions, gold was deposited on freshly polished titanium surface either by displacement reaction or by potentiodynamic polarization. Both of these procedures resulted in the formation of Au/TiO₂ composite layer over the titanium surface, although with quite different Au content. The electrochemical behaviour of these composite layers was examined in 0.1 M NaOH solution, both oxygen free and oxygen saturated, using rotating disc technique. In the potential region of oxygen reduction reaction, the Au/TiO₂ layer obtained by potentiodynamic polarization, displayed the voltammetric curve similar to that observed on (1 0 0) plane of Au monocrystal. The Koutecky-Levich analysis evidenced that 4e⁻ route of oxygen reduction dominates on both type of composite layers.     

Kinetic Analysis of Nonisothermal Reduction of Silica-Supported Nickel Catalyst Precursors in a Hydrogen Atmosphere

A series of silica-supported nickel catalyst precursors was synthesized with different SiO₂/Ni molar ratios. Reduction of Ni catalyst precursors with different SiO₂/Ni molar ratios under a hydrogen atmosphere was investigated at different heating rates. Kinetic parameters were determined using Kissinger–Akahira–Sunose isoconversional and invariant kinetic parameter methods. It was found that for all molar ratios, the apparent activation energy (E_a) is practically constant in the conversion range of 0.20 ≤ α ≤ 0.80. In the considered conversion range, following values of E_a were found: 134.5 kJ mol^?1 (SiO₂/Ni = 0.20), 139.6 kJ mol^?1 (SiO₂/Ni = 0.80), and 128.3 kJ mol^?1 (SiO₂/Ni = 1.15). It was established that the reduction of Ni catalyst precursors with different SiO₂/Ni molar ratios is a complex process and can be described by the ?esták–Berggren autocatalytic model. It was found that the reaction is more Langmuir–Hinshelwood type, as hydrogen dissociates rapidly on surface nuclei and the dissociated hydrogen reacts with the Ni–O active system. It was concluded that the reduction process proceeds through bulk nucleation, which is a dominant mechanism, where three-dimensional growth of crystals with polyhedron-like morphology exists. It was found that the Ni/Si ratio decreases after the reduction process. This has been explained by low Ni and higher Si surface concentrations. It has been disclosed that Ni dispersion decreases.     

Molecular and Clinical Implications of Variant Repeats in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is one of the most variable monogenic diseases at phenotypic, genetic, and epigenetic level. The disease is multi-systemic with the age at onset ranging from birth to late age. The underlying mutation is an unstable expansion of CTG repeats in the DMPK gene, varying in size from 50 to >1000 repeats. Generally, large expansions are associated with an earlier age at onset. Additionally, the most severe, congenital DM1 form is typically associated with local DNA methylation. Genetic variability of DM1 mutation is further increased by its structural variations due to presence of other repeats (e.g., CCG, CTC, CAG). These variant repeats or repeat interruptions seem to confer an additional level of epigenetic variability since local DNA methylation is frequently associated with variant CCG repeats independently of the expansion size. The effect of repeat interruptions on DM1 molecular pathogenesis is not investigated enough. Studies on patients indicate their stabilizing effect on DMPK expansions because no congenital cases were described in patients with repeat interruptions, and the age at onset is frequently later than expected. Here, we review the clinical relevance of repeat interruptions in DM1 and genetic and epigenetic characteristics of interrupted DMPK expansions based on patient studies.     

The effects of reaction conditions on the electrical conductivity of PAAG hydrogels

The effects of reaction conditions: concentration of crosslinker, monomer, initiator and gelatin and neutralization degree (ND) of acrylic acid (AA), of a graft radical crosslinking polymerization of AA and gelatin, on the specific electrical conductivity and the primary structural parameters of synthesized poly(acrylic acid)-g-gelatin (PAAG) hydrogels were investigated. It was established that: (a) electrical conductivity of all of the investigated hydrogels is higher than of distilled water; (b) the increasing concentration of crosslinker, monomer and initiator leads to the two linear distinct increases of electrical conductivity with different slopes (c) the increasing ND of AA leads to linear decrease in electrical conductivity and (d) gelatin concentration does not significantly influence the electrical conductivity of hydrogel. An analyses of the primary structural parameters of synthesized PAAG xerogels reveals that: (a) values of molar mass between crosslinks and distance between polymer chains are power form function on crosslink density (ρ_c); (b) the critical value of ρ_c corresponds to the percolation threshold of H⁺/K⁺ ions through the hydrogels network and (c) electrical conductivity of PAAG hydrogels is a power form function on ρ_c. Fractal model of conductivity of hydrogel is suggested and explained.     

Model predictive control with learning‐type set‐point: Application to artificial pancreatic β‐cell

A novel combination of model predictive control (MPC) and iterative learning control (ILC), referred to learning‐type MPC (L‐MPC), is proposed for closed‐loop control in an artificial pancreatic β‐cell. The main motivation for L‐MPC is the repetitive nature of glucose‐meal‐insulin dynamics over a 24‐h period. L‐MPC learns from an individual's lifestyle, inducing the control performance to improve from day to day. The proposed method is first tested on the Adult Average subject presented in the UVa/Padova diabetes simulator. After 20 days, the blood glucose concentrations can be kept within 68–145 mg/dl when the meals are repetitive. L‐MPC can produce superior control performance compared with that achieved under MPC. In addition, L‐MPC is robust to random variations in meal sizes within ±75% of the nominal value or meal timings within ±60 min. Furthermore, the robustness of L‐MPC to subject variability is validated on Adults 1–10 in the UVa/Padova simulator. © 2009 American Institute of Chemical Engineers AIChE J, 2010