Design and optimization of an electrocoagulation reactor for fluoride remediation in underground water sources for human consumption

Fluoride remediation in underground waters of volcanic origin was performed at laboratory scale using an electrocoagulation (EC) technique. The natural waters from certain volcanic springs on the island of Tenerife (Canary Islands, Spain) contain average fluoride concentrations in excess of 7 mg/L. Thus, it is necessary to treat the water for fluoride mitigation below the maximum acceptable concentration of 1.5 mg/L according to Spanish regulations for drinking water. The design and optimization of a sustainable process was accomplished using a progressive scale-up procedure involving three pilot reactors with different configurations and effective working volumes. A bipolar electrode cell design using aluminum electrodes was used in all cases. The good performance of the process was confirmed by reducing the fluoride concentration from 7.35 to 1.4 mg/L. The following optimized operating conditions were determined for a continuous flow cell system: current density, 10 mA/cm2; residence time, 10 min; and, half-period of polarity reversal, 1 min. Furthermore, the kinetics of the remediation process can be fitted using the Variable Order Kinetic (VOK) model, with a power relationship between fluoride concentration and residence time in the EC reacto

Cholesterol-Modified Caged siRNAs for Photoregulating Exogenous and Endogenous Gene Expression

siRNA has been widely applied in research and drug development due to its sequence-specific gene silencing ability. However, how to spatiotemporally control its function is still one of its challenges. Light, a fast and noninvasive trigger, is a promising tool for spatiotemporal control of gene expression. Here, we designed and synthesized a new series of caged siRNAs modified with single cholesterol at the 5′ terminal of antisense strand RNA through a photolabile linker (Chol-PL-siRNAs). We demonstrated that these caged siRNAs were successfully used to photochemically regulate both exogenous (<i>firefly luciferase</i> and <i>gfp</i>) and endogenous gene expression (mitotic kinesin-5, <i>Eg5</i>) in cells

Caged siRNAs with Single cRGD Modification for Photoregulation of Exogenous and Endogenous Gene Expression in Cells and Mice

RNA interference (RNAi) mediated gene silencing holds significant promise in gene therapy. It is very important to manually regulate the activity of small interference RNAs (siRNAs) in the controllable mode. Here, we designed and synthesized a series of caged siRNAs through bioconjugation of cyclo­(Arg-Gly-Asp-d-Phe-Lys) (cRGD) peptide to the 5′ end of siRNA through a photolabile linker. These cRGD modified caged siRNAs allowed for precise light-regulation of gene expression of two exogenous reporter genes (firefly luciferase and green fluorescent protein, GFP) and an endogenous gene (the mitosis motor protein, Eg5) in the integrin α_vβ₃ positive cells. This kind of bioconjugate further enabled photochemical activation of siRNA activity, and the target gene silencing was successfully achieved in tumor-bearing mice by intratumoral injection. This study also suggested that photomodulation of target gene expression using single cRGD caged siRNA at the 5′ end of antisense strand RNA inhibited siRNA activity probably due to three factors: (1) trapping of cRGD modified siRNA in endosome and lysosome, (2) the steric hindrance of cRGD, (3) the binding of cRGD to its corresponding receptor

Circular siRNAs for Reducing Off-Target Effects and Enhancing Long-Term Gene Silencing in Cells and Mice

Circular non-coding RNAs are found to play important roles in biology but are still relatively unexplored as a structural motif for chemically regulating gene function. Here, we investigated whether small interfering RNA (siRNA) with a circular structure can circumvent off-target gene silencing, a problem often observed with standard linear duplex siRNA. In the present work, we, for the first time, synthesized a series of circular siRNAs by cyclizing two ends of a single-stranded RNA (sense or antisense strand) to construct circular siRNAs that were more resistant to enzymatic degradation. Gene silencing of GFP and luciferase was successfully achieved using these circular siRNAs with circular sense strand RNAs and their complementary linear antisense strand RNAs. The off-target effect of sense strand RNAs was evaluated and no cross off-target effects were observed. In addition, we successfully achieved longer gene-silencing efficiency in mice with circular siRNAs than with linear siRNAs. These results indicate the promise of circular siRNAs for overcoming off-target effects of siRNAs and enhancing the possible long-term effect of siRNA gene silencing in basic research and drug development

Adapted digital health literacy and health information seeking behavior among lower income groups in Malaysia during the COVID-19 pandemic

Background: Misinformation has had a negative impact upon the global COVID-19 vaccination program. High-income and middle-income earners typically have better access to technology and health facilities than those in lower-income groups. This creates a rich-poor divide in Digital Health Literacy (DHL), where low-income earners have low DHL resulting in higher COVID-19 vaccine hesitancy. Therefore, this cross-sectional study was undertaken to assess the impact of health information seeking behavior on digital health literacy related to COVID-19 among low-income earners in Selangor, Malaysia.Methods: A quantitative cross-sectional study was conducted conveniently among 381 individuals from the low-income group in Selangor, Malaysia. The remote data collection (RDC) method was used to gather data. Validated interviewer-rated questionnaires were used to collect data via phone call. Respondents included in the study were 18 years and older. A normality of numerical variables were assessed using Shapiro-Wilk test. Univariate analysis of all variables was performed, and results were presented as means, mean ranks, frequencies, and percentages. Mann-Whitney U test or Kruskal Wallis H test was applied for the comparison of DHL and health information seeking behavior with characteristics of the participants. Multivariate linear regression models were applied using DHL as dependent variable and health information seeking behavior as independent factors, adjusting for age, gender, marital status, educational status, employment status, and household income.Results: The mean age of the study participants was 38.16 ± 14.40 years ranging from 18 to 84 years. The vast majority (94.6%) of participants stated that information seeking regarding COVID-19 was easy or very easy. Around 7 percent of the respondents cited reading information about COVID-19 on the internet as very difficult. The higher mean rank of DHL search, content, reliability, relevance, and privacy was found among participants who were widowed, had primary education, or unemployed. An inverse relationship was found between overall DHL and confidence in the accuracy of the information on the internet regarding COVID-19 (β = -2.01, 95% CI = -2.22 to -1.79).Conclusion: It is important to provide support to lower-income demographics to assist access to high-quality health information, including less educated, unemployed, and widowed populations. This can improve overall DHL