RF MEMS Switch Fabrication and Packaging

RF (Radio Frequency) MEMS (Micro Electro Mechanical Systems) technology is the application of micromachined mechanical structures, controlled by electrical signals and interacting with signals in the RF range. The applications of these devices range from switching networks for satellite communication systems to high performance resonators and tuners. RF MEMS switches are the first and foremost MEMS devices designed for RF technology. A specialized method for fabricating microsturctures called surface micromachining process is used for fabricating the RF MEMS switches. Die level packaging using available surface mount style RF packages. The packaging process involved the design of RF feed throughs on the Alumina substrates to the die attachment, wire bonding and hermetic sealing using low temperature processes

Development of a liposomal nanodelivery system for nevirapine

<p>Abstract</p> <p>Background</p> <p>The treatment of AIDS remains a serious challenge owing to high genetic variation of Human Immunodeficiency Virus type 1 (HIV-1). The use of different antiretroviral drugs (ARV) is significantly limited by severe side-effects that further compromise the quality of life of the AIDS patient. In the present study, we have evaluated a liposome system for the delivery of nevirapine, a hydrophobic non-nucleoside reverse transcriptase inhibitor. Liposomes were prepared from egg phospholipids using thin film hydration. The parameters of the process were optimized to obtain spherical liposomes below 200 nm with a narrow polydispersity. The encapsulation efficiency of the liposomes was optimized at different ratios of egg phospholipid to cholesterol as well as drug to total lipid. The data demonstrate that encapsulation efficiency of 78.14% and 76.25% were obtained at egg phospholipid to cholesterol ratio of 9:1 and drug to lipid ratio of 1:5, respectively. We further observed that the size of the liposomes and the encapsulation efficiency of the drug increased concomitantly with the increasing ratio of drug and lipid and that maximum stability was observed at the physiological pH. Thermal analysis of the drug encapsulated liposomes indicated the formation of a homogenous drug-lipid system. The magnitude of drug release from the liposomes was examined under different experimental conditions including in phosphate buffered saline (PBS), Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% fetal bovine serum or in the presence of an external stimulus such as low frequency ultrasound. Within the first 20 minutes 40, 60 and 100% of the drug was released when placed in PBS, DMEM or when ultrasound was applied, respectively. We propose that nevirapine-loaded liposomal formulations reported here could improve targeted delivery of the anti-retroviral drugs to select compartments and cells and alleviate systemic toxic side effects as a consequence.</p

Undernutrition & tuberculosis in India: Situation analysis & the way forward

Undernutrition and tuberculosis (TB) are linked and have a bidirectional relationship. Undernutrition increases the risk of TB which in turn, can lead to malnutrition. Undernutrition not only is a risk factor for progression of latent TB infection to active disease, but also increases the risk of drug toxicity, relapse and death once TB develops. The dietary intake of TB patients in the country is inadequate. Nutritional supplementation in patients with TB is associated with faster sputum conversion, higher cure and treatment completion rates, significant gain in body weight and body composition as well as better performance status. The Government of India has various social support schemes (including nutrition supplementation schemes) and policies, at the Centre as well as State levels. Here we discuss some successful examples and suggest a few solutions to address this gap; like considering TB patients as a vulnerable group for "Targeted Public Distribution System" and providing extra rations for the duration of treatment. Recommendations for the research community, civil societies, government organizations, non-governmental and corporate sector on the actions needed to achieve the goals of the End TB Strategy are also provided. Ultimately, reduction of TB burden in India and its elimination will require improving the nutritional status of the community as a whole

Derivation and external validation of a simple risk score to predict in-hospital mortality in patients hospitalized for COVID-19: A multicenter retrospective cohort study

ABSTRACT: As severe acute respiratory syndrome coronavirus 2 continues to spread, easy-to-use risk models that predict hospital mortality can assist in clinical decision making and triage. We aimed to develop a risk score model for in-hospital mortality in patients hospitalized with 2019 novel coronavirus (COVID-19) that was robust across hospitals and used clinical factors that are readily available and measured standardly across hospitals. In this retrospective observational study, we developed a risk score model using data collected by trained abstractors for patients in 20 diverse hospitals across the state of Michigan (Mi-COVID19) who were discharged between March 5, 2020 and August 14, 2020. Patients who tested positive for severe acute respiratory syndrome coronavirus 2 during hospitalization or were discharged with an ICD-10 code for COVID-19 (U07.1) were included. We employed an iterative forward selection approach to consider the inclusion of 145 potential risk factors available at hospital presentation. Model performance was externally validated with patients from 19 hospitals in the Mi-COVID19 registry not used in model development. We shared the model in an easy-to-use online application that allows the user to predict in-hospital mortality risk for a patient if they have any subset of the variables in the final model. Two thousand one hundred and ninety-three patients in the Mi-COVID19 registry met our inclusion criteria. The derivation and validation sets ultimately included 1690 and 398 patients, respectively, with mortality rates of 19.6% and 18.6%, respectively. The average age of participants in the study after exclusions was 64 years old, and the participants were 48% female, 49% Black, and 87% non-Hispanic. Our final model includes the patient\u27s age, first recorded respiratory rate, first recorded pulse oximetry, highest creatinine level on day of presentation, and hospital\u27s COVID-19 mortality rate. No other factors showed sufficient incremental model improvement to warrant inclusion. The area under the receiver operating characteristics curve for the derivation and validation sets were .796 (95% confidence interval, .767-.826) and .829 (95% confidence interval, .782-.876) respectively. We conclude that the risk of in-hospital mortality in COVID-19 patients can be reliably estimated using a few factors, which are standardly measured and available to physicians very early in a hospital encounter

Lack of association between plasma levels of non-nucleoside reverse transcriptase inhibitors & virological outcomes during rifampicin co-administration in HIV-infected TB patients.

BACKGROUND & OBJECTIVES Among patients with HIV-associated tuberculosis (TB), reduced plasma non-nucleoside reverse transcriptase inhibitors (NNRTI) concentrations during rifampicin (RMP) co-administration could lead to HIV treatment failure. This study was undertaken to examine the association between plasma nevirapine (NVP) and efavirenz (EFV) concentrations and virological outcomes in patients infected with HIV-1 and TB. METHODS This was a nested study undertaken in a clinical trial of patients with HIV-1 and TB, randomized to two different once-daily antiretroviral treatment (ART) regimens along with anti-TB treatment (ATT). Trough concentrations of plasma NVP and EFV were estimated at months 1 (during ATT and ART) and 6 months (ART only) by HPLC. Plasma HIV-1 RNA level >400 copies/ml or death within 6 months of ART were considered as unfavourable outcomes. Genotyping of CYP2B6 516G>T polymorphism was performed. RESULTS Twenty nine per cent of patients in NVP arm had an unfavourable outcome at 6 months compared to 9 per cent in EFV arm (PT polymorphism significantly associated with virologic outcome in patients receiving EFV-based regimen. INTERPRETATION & CONCLUSIONS Trough plasma concentrations of NVP and EFV did not show any association with response to ART in patients on ATT and once-daily ART. CYP2B6 516G>T polymorphism was associated with virologic outcome among patients on EFV

Eff ects of bidi smoking on all-cause mortality and cardiorespiratory outcomes in men from south Asia: an observational community-based substudy of the Prospective Urban Rural Epidemiology Study (PURE)

Background Bidis are minimally regulated, inexpensive, hand-rolled tobacco products smoked in south Asia. We examined the eff ects of bidi smoking on baseline respiratory impairment, and prospectively collected data for all-cause mortality and cardiorespiratory events in men from this region. Methods This substudy of the international, community-based Prospective Urban Rural Epidemiology (PURE) study was done in seven centres in India, Pakistan, and Bangladesh. Men aged 35–70 years completed spirometry testing and standardised questionnaires at baseline and were followed up yearly. We used multilevel regression to compare cross-sectional baseline cardiorespiratory symptoms, spirometry measurements, and follow-up events (all-cause mortality, cardiovascular events, respiratory events) adjusted for socioeconomic status and baseline risk factors between non-smokers, light smokers of bidis or cigarettes (≤10 pack-years), heavy smokers of cigarettes only (>10 packyears), and heavy smokers of bidis (>10 pack-years). Findings 14 919 men from 158 communities were included in this substudy (8438 non-smokers, 3321 light smokers, 959 heavy cigarette smokers, and 2201 heavy bidi smokers). Mean duration of follow-up was 5·6 years (range 1–13). The adjusted prevalence of self-reported chronic wheeze, cough or sputum, dyspnoea, and chest pain at baseline increased across the categories of non-smokers, light smokers, heavy cigarette smokers, and heavy bidi smokers (p<0·0001 for association). Adjusted cross-sectional age-related changes in forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) ratio were larger for heavy bidi smokers than for the other smoking categories. Hazard ratios (relative to non-smokers) showed increasing hazards for all-cause mortality (light smokers 1·28 [95% CI 1·02–1·62], heavy cigarette smokers 1·59 [1·13–2·24], heavy bidi smokers 1·56 [1·22–1·98]), cardiovascular events (1·45 [1·13–1·84], 1·47 [1·05–2·06], 1·55 [1·17–2·06], respectively) and respiratory events (1·30 [0·91–1·85], 1·21 [0·70–2·07], 1·73 [1·23–2·45], respectively) across the smoking categories. Interpretation Bidi smoking is associated with severe baseline respiratory impairment, all-cause mortality, and cardiorespiratory outcomes. Stricter controls and regulation of bidis are needed to reduce the tobacco-related disease burden in south Asia

Versatile Preparation of Fluorescent Particles Based on Polyphosphazenes: From Micro- to Nanoscale

A series of intrinsically fluorescent hydrophobic and amphiphilic polyphosphazenes with ethyl tryptophan (EtTrp) and poly(N-isopropylacrylamide) (PNIPAAm) or poly(ethylene glycol) (PEG) as hydrophobic and hydrophilic segments, respectively, are synthesized. Depending on polymer composition and preparation procedure, particles with diameters ranging from micro- to nanoscale can be prepared successfully, which might be used as a visible tracer, both in 14vitro or in 14vivo, in drug- or gene-delivery systems, as well as in other biomedical studies such as diagnostic medicine and brain research. Most importantly, in combination with the flexible synthesis and versatile modification of polyphosphazene, this method provides a general protocol to engineer a broad range of fluorescent particles with different properties based on diverse polymers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57545/1/2081_ftp.pd