Longitudinal bone mineral density changes in early rheumatoid arthritis

A prospective longitudinal study of patients with early RA was performed to examine the influence of disease duration, disease activity and physical activity on bone loss. Sixty-seven patients with non-steroid treated RA of less than 5 yr duration, including 16 patients with disease duration less than 6 months, had BMD measurements of the femoral neck and the lumbar spine over a 12-month period using dual energy X-ray absorptiometry. The BMD changes were compared with values from 72 control patients and were also correlated with serial measurements of disease activity (measured by the Stoke Index) and disability [measured by the Health Assessment Questionnaire (HAQ) score], at 3-monthly intervals over the 12-month period. No significant differences in BMD changes were found between RA patients and controls overall. Patients with disease duration of less than 6 months had significantly greater loss of BMD at the femoral neck (-3.9%, S.E.M. 1.5) than the remainder of the cohort (-0.2%, S.E.M. 0.7) (P = 0.02) and controls (-0.8%, S.E.M. 0.6). Lumbar spine BMD changes correlated with the initial Stoke Index (Rs-0.373, P = 0.01) but not mean Stoke Indices. There was no correlation of BMD changes with age or HAQ scores. These findings suggest that significant bone loss occurs within the first few months of disease in patients with RA.     

The polar cluster like behavior in Ti substituted BaZrO3 ceramics

In this paper we report the evolution of the polar cluster like behavior with the incorporation of Ti⁴⁺ ion in BaZrO₃ Ceramics. Dielectric behavior of BaZr_xTi_(1−x)O₃ (x = 1.00, 0.95, 0.90, 0.85) ceramics is studied in the temperature range from 300 to 30 K. Polar cluster like behavior becomes more prominent with the increase in content of Ti⁴⁺ ion. The dielectric relaxation is analyzed by Vogel–Fulcher relation and Arrhenius law. Frequency dependence of dielectric constant and low loss tangent of these materials can be useful for the potential applications at low temperature.     

Scattering center parameterization of wide-angle backscattered datausing adaptive Gaussian representation

We present a scattering center extraction algorithm to parameterize the backscattered data from complex targets collected over large angular apertures. This parameterization is based on a scattering center model of the target, but includes an aspect-dependent amplitude function for each scattering center. A two-dimensional (2-D) adaptive Gaussian representation (AGR) algorithm is used to extract the position and the amplitude function associated with each scattering center. The algorithm is tested with data generated by the Xpatch radar simulation code as well as chamber measurement data. The results show that a very good compression ratio can be achieved, resulting in a compact scattering center model of the target. Once such model is available, we can easily reconstruct range profiles and ISAR images at any aspect on the same plane with good accuracy     

A nonblocking transaction data flow graph based protocol forreplicated databases

Replicated data management systems adopt the 1-copy serializability criteria for processing transactions. In order to achieve this goal, many approaches rely on obtaining votes from other sites for processing update requests. In the proposed approach, a technique for generation of precedence graphs for each transaction execution is analyzed. The transaction data flow graph approach is a fully distributed approach. The proposed technique, is free from deadlocks, and avoids resubmission of transactions     

Utility of the radial-deviated, thumb-abducted lateral radiographic view for the diagnosis of hamate hook fractures: case report

Data from all 225 women operated on for ectopic pregnancy in 1992-1994 at Sahlgrenska University Hospital were collected and compared with three previous cross-sectional investigations from our hospital (1975-1979, 1981-1982 and 1986-1987) in order to evaluate the extent to which surgical treatment and post-operative complications have changed over a 20 year period. Laparoscopic surgery, which was not possible in the 1970s, was used in almost 85% of the ectopic pregnancies in 1992-1994. Conservative treatment was still the most frequently used technique. The complication rate was 1.2% in 1975-1979 when only laparotomies were carried out. After the introduction of laparoscopic surgery (1986-1987), the complication rate rose significantly (7.3%) and continued to increase even when this procedure was established as routine (14.2% in 1992-1994). Post-operative complications were most frequent after conservative laparoscopic surgery (24.4%) while there were no complications after laparotomies. In spite of increasing complication rates the frequency of patients in pre-shock, as well as the proportion of patients with heavy intra-abdominal bleeding and tubal rupture, decreased over time.     

Mechanical and Thermophysical Properties of Cerium Monopnictides

The ultrasonic attenuation due to phonon–phonon interaction, thermoelastic relaxation and dislocation damping mechanisms has been investigated in cerium monopnictides CeX (X: N, P, As, Sb and Bi) for longitudinal and shear waves along \({\langle }100{\rangle }\), \({\langle }110{\rangle }\) and \({\langle }111{\rangle }\) directions. The second- and third-order elastic constants of CeX have also been computed in the temperature range 0 K to 500 K using Coulomb and Born–Mayer potential upto second nearest neighbours. The computed values of these elastic constants have been applied to find out Young’s moduli, bulk moduli, Breazeale’s non-linearity parameters, Zener anisotropy, ultrasonic velocity, ultrasonic Grüneisen parameter, thermal relaxation time, acoustic coupling constants and ultrasonic attenuation. The fracture/toughness ratio is less than 1.75, which shows that the chosen materials are brittle in nature as found for other monopnictides. The drag coefficient acting on the motion of screw and edge dislocations due to shear and compressional phonon viscosities of the lattice have also been evaluated for both the longitudinal and shear waves. The thermoelastic loss and dislocation damping loss are negligible in comparison to loss due to Akhieser damping (phonon–phonon interaction). The obtained results for CeX are in qualitative agreement with other semi-metallic monopnictides.     

Zinc equilibria in submerged sodic soils as influenced by application of amendments

In a pot culture experiment, the effect of gypsum (50% of soil requirement), pyrites (equivalent to gypsum), farmyard manure (0.5 g per 100g soil) and Zn (10mg Zn kg^–1 soil) on Zn equilibria in Ghabdan and Langrian series of sodic soils was studied. The equilibrium soil solutions collected anaerobically after 1, 14, 28, 42, 56, 70 and 84 days of submergence were analysed for pH, EC, HCO₃ and Zn. Submergence markedly decreased soil solution pH and Zn up to 14 days and thereafter, the former slightly increased and the latter continued to decrease. Addition of amendments decreased soil solution pH in the order gypsum, pyrites and farmyard manure (FYM) and increased Zn concentration in the order FYM, gypsum and pyrites. The values of Zn potential (pZn + 2pOH) were within the range of pKsp for Zn(OH)₂-Zn²⁺ (aq) from 16 to 84 days of submergence in Ghabdan soil and from 9 to 42 days of submergence in Langrian soil, where later it shifted to ZnCO₃-Zn²⁺ (aq) system. Addition of FYM, pyrites and gypsum shortened the period of predominant existence of Zn(OH)₂-Zn²⁺ (aq) system to 40, 30 and 12 days in Ghabdan soil and 30, 20 and 6 days in Langrian soil respectively. After these periods the system was saturated with respect to ZnCO₃-Zn²⁺ (aq) except gypsum treatment where Zn-soil (unknown solid phases) -Zn²⁺ (aq) system controlled the solubility of Zn after 38 and 28 days of submergence of Ghabdan and Langrian soil respectively.     

Structural Health Monitoring by Piezo–Impedance Transducers. II: Applications

This paper, the second in a two-part series, presents a new methodology for structural identification and nondestructive evaluation by piezo–impedance transducers. The theoretical development and experimental validation of the underlying lead–zirconium–titanate (PZT)–structure interaction model was presented in the first part. In our newly proposed method, the damage in evaluated on the basis of the equivalent system parameters “identified” by the surface-bonded piezo–impedance transducer. As proof of concept, the proposed method is applied to perform structural identification and damage diagnosis on a representative lab-sized aerospace structural component. It is then extended to identify and monitor a prototype reinforced concrete bridge during a destructive load test. The proposed method was found to be able to successfully identify as well as evaluate damages in both the structures.     

Simplified Impedance Model for Adhesively Bonded Piezo-Impedance Transducers

The electromechanical impedance technique employs surface-bonded lead zirconate titanate piezoelectric ceramic patches as impedance transducers for structural health monitoring and nondestructive evaluation. The patches are bonded to the monitored structures using finitely thick adhesive bond layer, which introduces shear lag effect, thus invariably influencing the electromechanical admittance signatures. This paper presents a new simplified impedance model to incorporate shear lag effect into electromechanical admittance formulations, both one-dimensional and two-dimensional. This provides a closed-form analytical solution of the inverse problem, i.e. to derive the true structural impedance from the measured conductance and susceptance signatures, thus an improvement over the existing models. The influence of various parameters (associated with the bond layer) on admittance signatures is investigated using the proposed model and the results compared with existing models. The results show that the new model, which is far simpler than the existing models, models the shear lag phenomenon reasonably well besides providing direct solution of a complex inverse problem.