The role of T cells in polyethylene particulate induced inflammation

OBJECTIVE: To investigate the role of T lymphocytes in ultra-high molecular weight polyethylene (UHMWPE) induced inflammation in joint arthroplasty. METHOD: We address the role of T cells in wear induced inflammation by injecting the knee joints of both immune competent rats and mice and severe combined immunodeficient (SCID) mice with UHMWPE. Histological and immunohistochemical analysis of the synovial tissues was compared. Interaction between human T cells and UHMWPE particles was examined in vitro using T cell activation assays. RESULTS: Histological and immunohistochemical analysis of the knees of the immune competent animals showed significant UHMWPE induced inflammation. In contrast, the tissue in the SCID mice knee joints showed very little inflammatory response to UHMWPE despite phagocytosis of the particulate. Since the SCID mice have no functional T or B lymphocytes, it is highly likely that the lack of inflammation in knee joints may be due to the absence of mouse T cells, as the infiltration of T cells into the joint tissue may enhance the inflammatory response to UHMWPE particles. T cell activation assays showed that T cells were not directly activated by UHMWPE particles and the nature of the interaction was not revealed from these experiments. CONCLUSIONS: Although T cells are not directly involved in UHMWPE particle induced inflammation, as shown by the T cell activation assays, the histological data from the mice studies clearly show differences in the amplitude of inflammation from animals with and without functional T cells. Our studies suggest that the T cells may enhance the inflammatory response due to a bystander effect. Since the macrophages upon ingestion of UHMWPE particles release several cytokines including tumor necrosis factor-alpha, interleukin 1, and IL-6, it is possible that T cells in the vicinity of these macrophages may become attracted to the knee joint and activated due to cytokine release.     

The association between threat appraisals and psychological adjustment in partners of people with spinal cord injuries.

Objective: To explore the psychological factors associated with adjustment in partners of people with spinal cord injuries (SCIs). Participants and Design: Forty partners of people with SCIs. The study had a cross-sectional design. Main Outcome Measures: Beck Depression Inventory, the State Trait Anxiety Inventory Form Y-1, Social Provisions Scale, COPE, and an appraisal scale. Results: Approximately one third of partners reported levels of anxiety and depressive symptoms above the clinical cut-off points indicating elevated levels of emotional distress. Factors hypothesized to account for levels of emotional distress on the basis of the cognitive-appraisal model of stress and coping were found to be explanative. In particular, high threat appraisal, higher use of avoidance (emotion-focused) coping, and lack of approach (problem-focused) coping were found to predict higher levels of anxiety and depressive symptoms. Conclusions: Partners of people with SCIs are at risk of emotional distress. Factors that might help identify at-risk partners are identified and psychological interventions that might help partners are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A prospective randomized study comparing a catheter-valve with a standard drainage system

OBJECTIVE: To determine if the use of a catheter-valve rather than a standard drainage system decreases the morbidity associated with the use of a long-term catheter. PATIENTS AND METHODS: One hundred patients undergoing long-term catheterization were recruited into a prospective randomized study to investigate the acceptability and determine any increase in infection associated with the use of a catheter-valve, compared with the standard drainage system. Each patient participated in the study protocol for 3 months, during which the frequency of urinary tract infection was assessed, and the patients' views obtained using a standard questionnaire and by interview. RESULTS: Ninety-four patients completed the study; most (92%) were happy or satisfied with the valve, as opposed to only 35% of those using a standard drainage bag. There was no significant difference between the groups in the incidence of urinary tract infections. CONCLUSION: The patients who used the standard drainage system felt their level of activity was impaired, whereas the group who were using the valve did not. In the long-term the valve was cheaper and caused less morbidity, but because it is constructed to allow one-way flow, this was not associated with an increase in the incidence of urinary tract infections.     

Validation of a model of psychosocial determinants of occupational health of geriatric nurses

The purpose of this study was to verify a model of relationships between psychosocial factors and health for 8066 francophone nurses working in geriatric care in Québec. A random sample of 1990 subjects was drawn and a participation rate of 77.9% and 55% was obtained for the two-time study taken twelve months apart. Based on the theory of Maddi and Kobasa (1984), the model was reproduced for the two-time periods with the aid of structural equations. The analyses showed that three variables exert a direct influence on psychological distress: professional burnout, occupational stressors and hardiness. Also, variables have a direct effect on burnout: listed in order of importance, these are hardiness, occupational stressors, work support, active strategies of coping and employment status. In dealing with the work stressors, the nurses who are hardy make use of active strategies of coping and look for support form their colleagues. The results of the study help to better understand the psychological and social resources that best favor adaptation of working women in highly demanding work environments. The fallout of the study converges towards the quality of life of helping professionals and towards the cost and quality of health and social services.     

Radio-wave propagation for emerging wireless personal-communicationsystems

The present survey paper summarizes radio-propagation measurements and models for emerging wireless personal-communication systems. Both indoor and microcell-propagation environments are considered, and the problem of RF penetration into buildings is identified as an important area of research for emerging wireless-communication systems     

Response of dryland wheat to supplemental irrigation and rate and method of N application

A field experiment was conducted on dryland wheat (Triticum aestivum L.cv PBW 175) for four years on a sandy loam soil to evaluate the effect of supplemental irrigation in combination with rate and method of fertilizer N application. The experiment was a split-split plot design consisting of three irrigation treatments (rainfed, one preseeding irrigation and one preseeding + one postseeding irrigation) in the main plot: four fertilizer N rates (0, 40, 80 and 120 kg ha^–1) in the sub-plot and two methods of N application (drilled at the time of seeding and broadcast before preseeding irrigation) in the sub-sub plots. The crop response to supplementary irrigation(s) depended on the growing season water deficits. Broadcasting fertilizer N before preseeding irrigation resulted in the transporting of 39 per cent of the applied N to the sub-soil (20-60 cm depth). This resulted in better crop performance, particularly under low water supplies. A step wise regression was developed that showed water supplies beyond 26 cm of available water plus irrigation/rainfall from seeding to 45 days after were not productive and its distribution between pre- and post-fertilizer application periods affected water and applied N efficiencies. For higher crop yields under low water supply the fertilizer N broadcast before preseeding irrigation is suggested.     

Chelation and calcination promoted preparation of perovskite-structured BiFeO<Subscript>3</Subscript> nanoparticles: a novel magnetic catalyst for the synthesis of dihydro-2-oxypyrroles

Perovskite-structured Bismuth ferrite (BiFeO₃) nanoparticles as a novel heterogeneous catalyst were designed by an auto combustion route using a different chelating agent and calcination temperature. The effect of different chelating agents like disaccharide (sucrose), α-hydroxy acid (citric acid, tartaric acid), amide (urea) and calcination (150–750 °C) temperature on structure and the catalytic performance of BiFeO₃ have been analyzed. The catalytic performance of BiFeO₃ has been increased by modifying its synthesis with the addition of suitable organic compound and calcination. BiFeO₃ synthesized without the use of chelating agent gave very poor yield, i.e., 36.89%. The augmented effect of the chelating agent on the catalytic performance of BiFeO₃ was obtained in the order of blank < tartaric acid < sucrose < urea < citric acid, whereas the enhancing effect of calcination temperature in the order 150 °C < 450 °C < 550 °C < 650 °C > 750 °C. The calcination temperature results in augmentation in yield of approximately 30% with model reaction on increasing temperature from 150 to 650 °C. Different calcination temperatures (150–750 °C) have been employed to obtain single phase BiFeO₃ nanoparticles. All synthesized BiFeO₃ nanoparticles were fully characterized by FT-IR; XRD; VSM; BET; TGA; XPS and Raman spectroscopy. For the very first time ever we have used them as a recyclable magnetic nanocatalyst in the formation of highly substituted dihydro-2-oxypyrrole by using one-pot, three-component reaction of DMAD, aniline and formaldehyde in methanol at room temperature with 63–88% yield. All the synthesized oxypyrroles have been characterized by various spectroscopic techniques.     

Investigations for mechanical properties and biocompatibility of SS-316L implant prepared as rapid investment casting for batch production

In this work, a detailed procedure for the development of biomedical implant (SS-316L) by combining fused deposition modeling (FDM), chemical vapor smoothing (CVS), silicon molding (SM) and investment casting (IC) for batch production has been outlined. In spite of being biocompatible and bioactive within the body, the implant must possess good surface quality and dimensional accuracy along with sufficient hardness in order to reduce the wear inside the body. So in this research work, investigations have been made on the surface finish, dimensional accuracy and hardness of the implants by varying two controllable factors of the IC process (drying time of primary coating and mould thickness). The tolerance grades for the selected dimension of the casted implants were within the allowable range as defined in UNI EN 20286-I (1995) standard of ISO. The process capability indices (C_p and C_pk) values greater than 1.33 for the surface hardness and radial dimension indicated that the proposed process is statistically controlled. Further, in order to evaluate the biocompatibility, an in vitro study was conducted to ensure the attachment of mouse embryonic fibroblasts cells (NIH-3T3) to the casted samples. The results of invitro study indicated that samples were capable of supporting cell adhesion and cell proliferation and hence can be used for tissue engineering.     

Synthesis,characterisation and antimicrobial activity of manganese- and iron-doped zinc oxide nanoparticles

The present work reports study on antimicrobial activity of pure and doped ZnO nanocomposites. Polyvinyl pyrrolidone capped Mn- and Fe-doped ZnO nanocomposites were synthesised using simple chemical co-precipitation technique. The synthesised materials were characterised using transmission electron microscope (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF), Fourier transform infrared (FTIR) spectroscopy and ultraviolet (UV) visible spectroscopy. The XRD and TEM studies reveal that the synthesised ZnO nanocrystals have a hexagonal wurtzite structure with average crystalline size ～7–14 nm. EDXRF and FTIR study confirmed the doping and the incorporation of impurity in ZnO nanostructure. The antimicrobial activities of nanoparticles (NPs) were studied against fungi, gram-positive and gram-negative bacteria using the standard disc diffusion method. The photocatalytic activities of prepared NPs were evaluated by degradation of methylene blue dye in aqueous solution under UV light irradiation. Experimental results demonstrated that ZnO NPs doped with 10% of Mn and Fe ions showed maximum antimicrobial and photodegradation efficiency in contrast with that of the 1% loading. The enhancement in antimicrobial effect and photocatalytic degradation is attributed to the generation of reactive oxygen species due to the synergistic effects of Mn and Fe loading.