A Low-Power BFSK/OOK Transmitter for Wireless Sensors

In recent years, significant improvements in semiconductor technology have allowed consistent development of wireless chipsets in terms of functionality and form factor. This has opened up a broad range of applications for implantable wireless sensors and telemetry devices in multiple categories, such as military, industrial, and medical uses. The nature of these applications often requires the wireless sensors to be low-weight and energy-efficient to achieve long battery life. Among the various functions of these sensors, the communication block, used to transmit the gathered data, is typically the most power-hungry block. In typical wireless sensor networks, transmission range is below 10 meters and required radiated power is below 1 milliwatt. In such cases, power consumption of the frequency-synthesis circuits prior to the power amplifier of the transmitter becomes significant. Reducing this power consumption is currently the focus of various research endeavors. A popular method of achieving this goal is using a direct-modulation transmitter where the generated carrier is directly modulated with baseband data using simple modulation schemes. Among the different variations of direct-modulation transmitters, transmitters using unlocked digitally-controlled oscillators and transmitters with injection or resonator-locked oscillators are widely investigated because of their simple structure. These transmitters can achieve low-power and stable operation either with the help of recalibration or by sacrificing tuning capability. In contrast, phase-locked-loop-based (PLL) transmitters are less researched. The PLL uses a feedback loop to lock the carrier to a reference frequency with a programmable ratio and thus achieves good frequency stability and convenient tunability. This work focuses on PLL-based transmitters. The initial goal of this work is to reduce the power consumption of the oscillator and frequency divider, the two most power-consuming blocks in a PLL. Novel topologies for these two blocks are proposed which achieve ultra-low-power operation. Along with measured performance, mathematical analysis to derive rule-of-thumb design approaches are presented. Finally, the full transmitter is implemented using these blocks in a 130 nanometer CMOS process and is successfully tested for low-power operation

Biosynthesis of silver nanoparticles from Cymbopogon citratus leaf extract and evaluation of their antimicrobial properties

Background: Silver nanoparticles (AgNPs) are toxic to microorganisms and can potentially kill multidrug-resistant bacteria. Nanoparticles can be synthesized in many ways, such as physical or chemical methods. Recently, it has been found that plant molecules can perform the same reduction reactions necessary for the production of nanoparticles but in a much more efficient way. Results: Here, green chemistry was employed to synthesize AgNPs using leaf extracts of Cymbopogon citratus. The effects of different parameters such as temperature, pH, and the volume of plant extract were also tested using their absorbance pattern at different wavelengths. The Surface Plasmon Resonance (SPR) changed with the changes in parameters. Changes in temperature from 20 °C to 60 °C have changed the highest absorbance from 0.972 to 3.893 with an SPR of 470 nm. At higher pH (11.1), the particles become highly unstable and have irregular shapes and sizes. The peak shifts to the right at a lower pH level (3.97), indicating a smaller but unstable compound. We have also investigated the effect of the volume of plant extracts on the reaction time. The sample with the highest amount of plant extract showed the most absorbance with a value of 0.963 at λmax, calculated to be 470 nm. The total formation of the AgNPs was observed visually with a color change from yellow to brownish-black. UV-visible spectroscopy was used to monitor the quantitative formation of AgNPs, showing a signature peak in absorbance between 400 and 500 nm. We have estimated the size of the nanoparticles as 47 nm by comparing the experimental data with the theoretical value using Mieplot. The biosynthesized AgNPs showed enhanced antibacterial activity against several multidrug-resistant bacteria, determined based on the minimal inhibitory concentration and zone of inhibition. Conclusion: The findings of this study indicate that an aqueous extract of C. citratus can synthesize AgNPs when silver nitrate is used as a precursor, and AgNPs act as antimicrobial property enhancers, which can be used to treat antibiotic-resistant bacteria. Hence, mass production and green synthesis of AgNPs from C. citratus will be able to increase the overall health of the general population. Moreover, it will enormously reduce the costs for drug development and provide employment options in the remotely located source areas. Finally, our findings will influence further studies in this field to better understand the properties and applications of AgNPs and ultimately contribute to improving planetary health by increasing immunity with high biocompatibility and less drug toxicity

COMO É QUE OS ESTUDANTES DE MEDICINA E ENFERMAGEM VEEM A TECNOLOGIA DE SAÚDE? UM ESTUDO DE VALIDAÇÃO PSICOMÉTRICA DO QUESTIONÁRIO DE AVALIAÇÃO DE USABILIDADE EM BANGLADESH

The modernization of healthcare delivery is a reality in various international settings. To ensure efficient and safe use of the diverse forms of healthcare technology available, professionals and students must be receptive to incorporating such tools into their practice. Currently, there is no instrument in Bangladesh to assess healthcare students’ technology acceptance. Objective: To translate, culturally adapt, and validate the Usability Evaluation Questionnaire (UtEQ) among Bangladeshi healthcare students. Method: A cross-sectional study with a methodological approach was conducted in two phases. The first phase involved the translation of the UtEQ questionnaire to Bengali, following the six stages proposed by Beaton et al. In the second phase, the psychometric properties of the questionnaire were evaluated using a non-probability sample of 486 undergraduate healthcare students from three higher education institutions in Bangladesh. Confirmatory factor analysis was performed, and the Cronbach’s alpha coefficient was estimated to find out the internal consistency. Results: Internal consistency was found to be excellent for all scale dimensions, ranging from 0.88 to 0.92, while confirmatory factor analysis showed adequate goodness-of-fit indicators. Conclusion: The UtEQ-B provides a reliable and valid method for healthcare educators and researchers to assess technology acceptance among healthcare students during clinical training in Bangladesh.A modernização da prestação de cuidados de saúde é uma realidade em vários contextos internacionais. Para garantir a utilização eficiente e segura das diversas formas de tecnologia em saúde disponíveis, os profissionais e estudantes devem estar receptivos à incorporação dessas ferramentas na sua prática. Atualmente, não existe em Bangladesh um instrumento para avaliar a aceitação da tecnologia pelos estudantes de saúde. Objetivo: Traduzir, adaptar culturalmente e validar o Questionário de Avaliação da Usabilidade (UtEQ) entre estudantes de saúde de Bangladesh. Método: Foi realizado um estudo transversal com uma abordagem metodológica em duas fases. A primeira fase envolveu a tradução do questionário UtEQ para bengali, seguindo as seis etapas propostas por Beaton et al. Na segunda fase, foram avaliadas as propriedades psicométricas do questionário usando uma amostra não probabilística de 486 estudantes de graduação em saúde de três instituições de ensino superior em Bangladesh. Foi realizada uma análise fatorial confirmatória e estimou-se o coeficiente alfa de Cronbach para verificar a consistência interna. Resultados: Foi encontrada uma consistência interna excelente para todas as dimensões da escala, variando de 0,88 a 0,92, enquanto a análise fatorial confirmatória mostrou indicadores adequados de ajuste. Conclusão: O UtEQ-B fornece um método confiável e válido para educadores e pesquisadores em saúde avaliarem a aceitação da tecnologia entre estudantes de saúde durante o treinamento clínico em Bangladesh

The Etiology of Childhood Pneumonia in Bangladesh

BACKGROUND: Pneumonia remains the leading infectious cause of death among children <