Uncovering the Unusual: A Case of Mixed Connective Tissue Disease With Rare Presentation, Atypical Complications, and Therapeutic Dilemmas.

Mixed connective tissue disease (MCTD) is an overlap syndrome characterized by features of systemic lupus erythematosus, scleroderma, and polymyositis, along with the presence of the U1RNP antibody. A 46-year-old female patient presented with severe anemia, cough, and breathlessness, and was diagnosed with cold agglutinin disease, a type of autoimmune hemolytic anemia (AIHA). Autoimmune workup revealed MCTD by positive antinuclear and U1RNP antibodies. She had bilateral miliary mottling on X-ray and a tree-in-bud appearance on high-resolution computed tomography of the thorax, which were suggestive of pulmonary tuberculosis. Standard therapy with steroids was not advisable. She was subsequently started on anti-tuberculosis treatment (anti-Koch's therapy), followed by steroid therapy and immunosuppressive therapy after three weeks. The patient responded well to treatment, but after two months, she developed cytomegalovirus (CMV) retinitis. Adult-onset CMV disease may occur as a result of primary infection, reinfection, or activation of a latent infection. Although not directly related, it can occur as an atypical association in the setting of immunosuppressive therapy. Morbidity and mortality are significantly increased in this population secondary to infectious potentiation: immunosuppression causes infections, and infections cause AIHA. The management of MCTD and secondary AIHA and immunosuppression poses a therapeutic challenge.

Effect of Multi-Walled Carbon Nanotubes and Carbon Fiber Reinforcements on the Mechanical and Tribological Behavior of Hybrid Mg-AZ91D Nanocomposites.

Magnesium matrix composites are extensively used in automotive and structural applications due to their low density, high strength, and wear-resistant properties. To reach the scope of industry needs, research is carried out regarding enhancing the mechanical and tribological behavior of the magnesium composites by reinforcing the nano-sized reinforcements. In the present work, research has been carried out to enhance the properties of the magnesium AZ91D hybrid composite by reinforcing carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) with varying weight percentages (AZ91D + 0.5% CF's + 0.5% MWCNT and AZ91D + 0.75% CF's + 0.75% MWCNT, respectively). The experimental tests were carried out to evaluate the mechanical and tribological behavior of the composites. The test results showed that the addition of CF and MWCNT reinforcements improved the hybrid Mg composite's hardness, tensile strength, and impact strength compared to the base Mg matrix. The AZ91D + 0.75% CF's + 0.75% MWCNT hybrid composite showed a 19%, 35%, and 66% increased hardness, tensile strength, and impact strength, respectively, compared to the base Mg AZ91D. The wear test results also showed the improved wear resistance of the Mg composite compared to the base matrix. The enhanced wear resistance of the composite is due to the addition of hard MWCNT and CF reinforcements. The wear rate of the AZ91D + 0.75%CF's + 0.75% MWCNT composite for a load of 30 N at a sliding distance of 1500 m is lower as compared to the base matrix. The SEM micrographs of the worn surfaces revealed the existence of abrasive wear. The improved mechanical and tribological behavior of the magnesium composite is also due to the homogeneous distribution of the hard reinforcement particles along the grain boundaries.