Monitoring of cyanobacteria using derivative spectrophotometry and improvement of the method detection limit by changing pathlength

Effective monitoring tools and methods are needed for the early detection and management of cyanobacteria in water bodies to minimize their harmful impacts on the environment and public health. This research investigated changing the cuvette pathlength (10-, 50-, and 100-mm) to improve the detection of cyanobacteria using UV-Vis spectrophotometry with subsequent application of derivative spectrophotometry and Savitzky-Golay (S-G) transformation. A non-toxigenic strain of blue-green cyanobacteria, Microcystis aeruginosa (CPCC 632), and a green algae strain for comparison, Chlorella vulgaris (CPCC 90), were studied in a wide range of concentrations (955,000–1,855 cells/mL). In each concentration range, method detection limits were established with absorbance measurements and S-G first derivative of absorbance using 10-, 50-, and 100-mm cuvette pathlengths. Increasing the cuvette pathlength from 10 to 100 mm resulted in a 15-fold improvement in sensitivity with absorbance and a 13-fold improvement with S-G first derivative of absorbance for M. aeruginosa. Overall, adoption of 100 mm pathlength and application of S-G derivative spectra improved the method detection limit for M. aeruginosa from 337,398 cells/mL to 4,916 cells/mL, which is below the WHO guideline for low probability of adverse health effects (<20,000 cells/mL). Similarly, the detection limit for C. vulgaris was improved from 650,414 cells/mL to 11,661 cells/mL. The results also showed that spectrophotometry could differentiate M. aeruginosa from C. vulgaris based on the variations in their pigment absorbance peaks.

Variations of arsenic in groundwater from a transect in Van Phuc village, Hanoi

In this study, the author report detailed results of the variation of arsenic in groundwater along a transect in an area near the Hanoi city centre. The results showed that 64% of collected samples exceeded the WHO guideline value for arsenic concentration in drinking water. The arsenic concentration varied in a wide range, strongly depending on the sediment characteristics of each zone along the transect. Aside from As, groundwater in this area also was contaminated by elevated concentrations of Fe, Mn, and ammonium. The study also pointed out a positive correlation between As and reductive chemical species, namely DOC, NH4+, and CH4 in groundwater. Although there is no clear trend in the correlation between As and Fe, Mn, it can be concluded that the formation of arsenic in groundwater in the study area was due to the reductive dissolution of As-bearing iron minerals under the presence of organic matter.

Spatial Prioritization Model of COVID-19 Vaccine Allocation in Neighborhoods of Mashhad Using AHP and Fuzzy Logic

Introduction: With the global outbreak of the COVID-19 and the high mortality rate of this disease, indicates the decision-making and finding a solution to control its spread. One of the most effective ways is to use the COVID-19 vaccine. Due to the limited supply of corona vaccines, the distribution of this vaccine is generally prioritized and is done allocation among individuals. Methods: In this descriptive correlational study, GIS, AHP tools, and fuzzy logic were used to achieve the goal of prioritizing and allocating corona vaccine in Mashhad neighborhoods. Neighborhoods prioritization in four scenarios was analyzed; Includes scenario AHP, scenario the WHO guideline, scenario guideline of the Ministry of Health and Medical Education of Iran, and scenario localized collective wisdom. Results: The output of neighborhood prioritization of the four mentioned scenarios has been determined and categorized into five classes. In the AHP scenario, the lowest percentage (8.89%) while the localized collective wisdom highest percentage (42.22%) allocate to priority 1 neighborhoods. There is generally no high correlation between the results and only the scenario of the Ministry of Health and Medical Education and the localized collective wisdom correlates 0.82. Conclusion: Considering the COVID-19 vaccine shortage, spatial allocation based on the presented guidelines is a reliable method that can meet the basic criteria for allocating limited treatment resources. In This research, the spatial allocation was conducted and 180 neighborhoods throughout the city of Mashhad were identified and prioritized in different scenarios that can assist decision-makers.

Associations between Physical Activity and Mental Health in Iranian Adolescents during the COVID-19 Pandemic: An Accelerometer-Based Study

Using self-reported questionnaires, several studies found that social isolation during the COVID-19 pandemic has significantly changed the level of physical activity (PA) in children and adolescents. Since the objectivity of self-reported PA is limited in several ways, we used modern accelerometers in this study to assess the PA levels of male and female adolescents during the pandemic-related lockdown. Moreover, the association of PA with mental health of the adolescents were analyzed. A total of 136 students (76 girls, mean age of 16.28 ± 0.97 years) from various schools in Iran wore the accelerometer (ActiGraph GT3X-BT) for seven consecutive days. Mental health was measured through the Depression, Anxiety, Stress Scale-21 of Lovibond and Lovibond (1995). Descriptive statistics and independent t-tests were used to analyze the PA levels of male and female students, and linear regressions were computed to examine whether PA predicts mental health status. On average, the daily time spent in moderate-to-vigorous PA (MVPA) was 18.47 min, which is clearly below the WHO guideline of at least 60 min of MVPA per day. Only 4% of adolescents showed MVPA for more than 30 min per day. Male students were significantly more active than their female peers (p = 0.015). As expected, MVPA was negatively associated with mental health issues such as depression, anxiety, and stress. However, the majority of adolescents reported symptoms of mild-to-moderate mental health disorders. These results emphasize the need for targeted strategies and offerings geared to young people’s needs and preferences to promote an adequate level of PA and good mental health during and after the ongoing pandemic.

The WHO guideline on drugs to prevent COVID-19: small numbers- big conclusions

The World Health Organization (WHO) living guideline on drugs to prevent COVID-19 has recently advised that ongoing trials evaluating hydroxychloroquine in chemoprophylaxis should stop. The WHO guideline cites “high certainty” evidence from randomised controlled trials (RCTs) that hydroxychloroquine prophylaxis does not reduce mortality and does not reduce hospital admission, and “moderate certainty” evidence of poor tolerability because of a significantly increased rate of adverse events leading to drug discontinuation. Yet there is no such evidence. In the three pre-exposure chemoprophylaxis RCTs evaluated in the guideline there were no deaths and only two COVID-19-related hospital admissions, and there was a mistake in the analysis of the number of discontinuations (after correction there is no longer a statistically significant difference between those taking the drug and the controls). Guidelines on the prevention and treatment of COVID-19 should be based on sufficient verified evidence, understanding of the disease process, sound statistical analysis and interpretation, and an appreciation of global needs. The WHO living guideline on the prevention of COVID-19 should retract the advice to stop research on hydroxychloroquine chemoprophylaxis, should correct its errors, and should revise its guidance.

COVID-19, Suffering and Palliative Care: A Review

According to the WHO guideline, palliative care is an integral component of COVID-19 management. The relief of physical symptoms and the provision of psychosocial support should be practiced by all healthcare workers caring for COVID-19 patients. In this review, we aim to provide a simple outline on COVID-19, suffering in COVID-19, and the role of palliative care in COVID-19. We also introduce 3 principles of palliative care that can serve as a guide for all healthcare workers caring for COVID-19 patients, which are (1) good symptom control, (2) open and sensitive communication, and (3) caring for the whole team. The pandemic has brought immense suffering, fear and death to people everywhere. The knowledge, skills and experiences from palliative care could be used to relieve the suffering of COVID-19 patients.