Effect of Mn Doping on the Optical and Electrical Properties of Double Perovskite Sr2TiCoO6

A new series of Sr₂TiCo_1−xMn_xO₆ (0.0 ≤ x ≤ 0.7) materials has been synthesized using the conventional solid-state method. In this research, X-ray diffraction (XRD) results showed that Mn was successfully doped at the Co site in a cubic structure with monoclinic P2₁/n space group. The effect of Mn cation substitution on the structural, optical and electrical performance of Sr₂TiCo_1−xMn_xO₆ double perovskite was investigated. The optical study revealed a nonlinearity pattern of the band gap that is referred to as the band gap bowing trend. Results from optical and Rietveld refinement supports that the band gap bowing trend is correlated with the charge distribution that produces unique effects on structural and size changes due to the Co-Mn compositions. The morphological scanning electron microscopy studies also showed that larger crystallite sizes were developed when dopant was added. Furthermore, increases in the conductivities support the lowering band gap of Mn-doped samples. Here, the intermixing of the atomic orbitals of Co-Mn provides an efficient interlink electrical pathway to improve conductivity and exhibits a high dielectric property at room temperature. These values are strong evidence that STCM material will be suitable for applications in the semiconductor industry.     

Confronting the HIV,Tuberculosis, Addiction,and Incarceration Syndemic in Southeast Asia: Lessons Learned from Malaysia

Throughout Southeast Asia, repressive drug laws have resulted in high rates of imprisonment in people who inject drugs (PWID) and people living with HIV (PLH), greatly magnifying the harm associated with HIV, tuberculosis, and addiction. We review findings from Malaysia’s largest prison to describe the negative synergistic effects of HIV, tuberculosis, addiction, and incarceration that contribute to a ‘perfect storm’ of events challenging public and personal health and offer insights into innovative strategies to control these converging epidemics. The majority of PLH who are imprisoned in Malaysia are opioid dependent PWID. Although promoted by official policy, evidence-based addiction treatment is largely unavailable, contributing to rapid relapse and/or overdose after release. Similarly, HIV treatment in prisons and compulsory drug treatment centers is sometimes inadequate or absent. The prevalence of active tuberculosis is high, particularly in PLH, and over 80 % of prisoners and prison personnel are latently infected. Mandatory HIV testing and subsequent segregation of HIV-infected prisoners increases the likelihood of tuberculosis acquisition and progression to active disease, amplifying the reservoir of infection for other prisoners. We discuss strategies to control these intersecting epidemics including screening linked to standardized treatment protocols for all three conditions, and effective transitional programs for released prisoners. For example, recently introduced evidence-based interventions in prisons like antiretroviral therapy (ART) to treat HIV, isoniazid preventive therapy to treat latent tuberculosis infection, and methadone maintenance to treat opioid dependence, have markedly improved clinical care and reduced morbidity and mortality. Since introduction of these interventions in September 2012, all-cause and HIV-related mortality have decreased by 50.0 % and 75.7 %, respectively. We discuss the further deployment of these interventions in Malaysian prisons.     

MRI and CT findings of cryptococcal vaginitis

Cryptococcus neoformans is a yeast like fungus, which is commonly found in bird droppings, especially pigeons. Most cases of cryptococcal infections occur in immunocompromised patients or in those who are on long term immunosuppressant therapies. Cryptococcal infection usually presents as a meningoencephalitis or a pulmonary infection. Skin, bone and genital infections are very rare. We report the second case of vaginal cryptococcossis to be reported in English literature and the first to be imaged with CT and MRI.     

Human Plasmodium knowlesi infections in Klang Valley, Peninsula Malaysia: a case series

We report seven cases of naturally acquired human Plasmodium knowlesi infections which were admitted to our centre from July 2007 till June 2008. Diagnosis was confirmed by nested PCR. Cases of P. knowlesi infections, dubbed the fifth type of human malaria, have been reported in East Malaysia (Sabah and Sarawak) as well as in the state of Pahang in Peninsula Malaysia. These seven patients appear to be the first few reported cases of P. knowlesi infection in the Klang valley, Peninsula Malaysia. We then discuss the characteristics of human P. knowlesi infections, which include its natural hosts, responsible vectors, clinical presentation, and the treatment of such infections.     

A young patient with history of Kawasaki disease presenting with triple vessel disease

Kawasaki disease is primarily a condition that affects young children and it is associated with cardiac morbidity and mortality. This disease has been known to cause coronary artery aneurysms which occurs as a sequelae of vasculitis. The progression of triple vessel disease in adult which results from cardiac complications from Kawasaki disease is rare. We report a case of a young man with history of Kawasaki disease at infancy presenting with triple vessel disease requiring cardiac bypass surgery at the age of 20 years old.