Design of a CSK-CDMA Based Indoor Visible Light Communication Transceiver using Raspberry Pi and LabVIEW

Visible Light Communication (VLC) has drastically drawn the attention of both academia and industry as it can offer simultaneous lighting and data communication in an indoor environment. Additionally, VLC also tender a viable means to assuage the radio spectrum crunch. However, the data rate of the VLC system is choked because of the limited modulation bandwidth of Light Emitting Diode (LED), baseband modules, and intersymbol interference (ISI). In this article, an indoor VLC based software-defined radio (SDR) is designed and implemented that make use of Color Shift Keying (CSK) modulation, Code Division Multiple Access (CDMA) technique, and Raspberry Pi (RPi) to enabled the ISI free high data rate communication. The SDR is designed in LabVIEW software interfaced with the MATLAB and tested for text transmission. Numerous experiments were conducted on SDR at different alignments of transmitter and receiver. Our findings through experimentation showed that the SDR delivers an improved data rate of 2.645Mbps. Over and above, MATLAB based simulation packages are also conceived that validate the effectiveness of the proposed CSK-CDMA based VLC system. The bit-error-rate (BER) results of the proposed system are compared with the traditional CSK-OOK based VLC system. The results are quite impressive and show remarkable coding gain

The Role and Efficacy of Vitamin C in Sepsis: A Systematic Review and Meta-Analysis

Clinical rationale for study: Despite advancements in critical care, the mortality rate of sepsis remains high, with an overall poor prognosis. There is a complex pathophysiology of a lethal cascade of cytokines and inflammatory proteins underlying sepsis. The use of vitamin C can theoretically suppress the inflammatory cascade but remains a questionable practice due to a lack of conclusive evidence. Aims of the study: To appraise the therapeutic role of vitamin C in sepsis. Materials and methods: A systematic review was conducted on PubMed, Embase, and the Central Cochrane Registry. The study included randomized clinical trials (RCTs) with vitamin C as an intervention arm in the septic patient population. For continuous variables, the difference in means (MD) and for discrete variables, the odds ratio (OR) was used. For effect sizes, a confidence interval of 95% was used. A p-value of less than 0.05 was used for statistical significance. The analysis was performed using a random-effects model irrespective of heterogeneity. Heterogeneity was evaluated using the I2 statistic. Results: 23 studies were included with the total sample size of 2712 patients. In patients treated with vitamin C, there was a statistically significant reduction in the mortality: OR = 0.778 (0.635 to 0.954), p = 0.016; the sequential organ failure assessment score (SOFA): MD = −0.749 (−1.115 to −0.383), p < 0.001; and the duration of vasopressor requirement: MD = −1.034 days (−1.622 to −0.445), p = 0.001. No significant difference was found in the hospital or ICU length of stay. Conclusions and clinical implications: Vitamin C treatment regimens were associated with reduced mortality, SOFA score, and vasopressor requirement compared to the control in sepsis. Given its low cost and minimal adverse effects, we strongly encourage further large, randomized trials to establish vitamin C as a standard of care in sepsis management