Three-Dimensional Magnetotelluric (MT) Modeling of the Northern Negros Geothermal Project, Central Philippines

The latest magnetotelluric (MT) survey was conducted in the Northern Negros Geothermal Project (NNGP), which is one of the geothermal fields being developed in the Philippines, from December, 2010 to April, 2011. 66 new MT soundings were added to the previous MT dataset. The new stations were located mainly in the southeastern and southern regions to define the extent of drilled high-temperature resource in these areas. Phase tensor analysis show that the MT data in general is only 1-D in the short period range of 100 ohm-m resistive top layer, a middle 20 ohm-m moderately resistive bottom layer. The highly resistive top layer is associated with the relatively fresh volcanic deposits of the Canlaon Volcanics (CnV). Correlating the 3-D resistivity structure with subsurface data from the drilled wells shows that the thick conductive layer overlaps with the low-temperature alteration minerals such as smectite while the moderately resistive bottom layer coincides with the high-temperature alteration minerals like illite and epidote. These observations are also consistent with the measured well temperatures wherein the elevated temperatures drilled beneath the Pataan sector coincide with the shallow occurence or doming portion of the bottom resistive layer. Tracing the shallow occurrence of the bottom resistive layer revealed a northeast extension to the drilled resource beneath Pataan. The delineated resource area in Pataan is about 3 to 7 km². Other possible high-temperature areas are located within the Upper Hagdan and Hardin Sang Balo sectors. However, resolution of the resistivity structure is not well pronounced in these areas due to limited data coverage

Three-Dimensional Magnetotelluric (MT) Modeling of the Northern Negros Geothermal Project, Central Philippines

The latest magnetotelluric (MT) survey was conducted in the Northern Negros Geothermal Project (NNGP), which is one of the geothermal fields being developed in the Philippines, from December, 2010 to April, 2011. 66 new MT soundings were added to the previous MT dataset. The new stations were located mainly in the southeastern and southern regions to define the extent of drilled high-temperature resource in these areas. Phase tensor analysis show that the MT data in general is only 1-D in the short period range of 100 ohm-m resistive top layer, a middle 20 ohm-m moderately resistive bottom layer. The highly resistive top layer is associated with the relatively fresh volcanic deposits of the Canlaon Volcanics (CnV). Correlating the 3-D resistivity structure with subsurface data from the drilled wells shows that the thick conductive layer overlaps with the low-temperature alteration minerals such as smectite while the moderately resistive bottom layer coincides with the high-temperature alteration minerals like illite and epidote. These observations are also consistent with the measured well temperatures wherein the elevated temperatures drilled beneath the Pataan sector coincide with the shallow occurence or doming portion of the bottom resistive layer. Tracing the shallow occurrence of the bottom resistive layer revealed a northeast extension to the drilled resource beneath Pataan. The delineated resource area in Pataan is about 3 to 7 km². Other possible high-temperature areas are located within the Upper Hagdan and Hardin Sang Balo sectors. However, resolution of the resistivity structure is not well pronounced in these areas due to limited data coverage

Expanding Access to HIV Viral Load Testing: A Systematic Review of RNA Stability in EDTA Tubes and PPT beyond Current Time and Temperature Thresholds

Background: HIV viral load (VL) testing is the gold standard for antiretroviral treatment monitoring, but many barriers exist to VL testing in resource-limited settings, including storage and transport limitations for whole blood and plasma. Data from various studies indicate that HIV RNA is stable beyond current recommendations. We conducted a systematic review to assess stability data of HIV RNA in whole blood and plasma across times and temperatures. Methods and Findings: Using a pre-defined protocol, five databases were searched for studies where blood samples from HIV patients were stored at time and temperature points that exceeded manufacturer recommendations. RNA stability, the primary outcome, was measured by the difference in means compared to samples stored within established thresholds. RNA stability was defined as ≤0.5 log degradation. The search identified 10,716 titles, of which nine full-text articles were included for review. HIV RNA maintained stability in EDTA whole blood and plasma at all measured time points up to 168 hours when stored at 4°C, while stability was detected at 72 hours (95% confidence) in whole blood at 25°C, with data points before and beyond 72 hours suggesting stability but not reaching statistical significance. For EDTA plasma stored at 30°C, stability was maintained up to 48 hours (95% confidence), with OLS linear regression estimates up to 127 hours, suggesting stability. Overall, quality of studies was moderate. Limitations included small sample sizes, few studies meeting inclusion criteria, and no studies examining RNA stability in low viremia (<3,000 copies/mL) environments. Conclusions: Whole blood and plasma samples in EDTA may remain stable under conditions exceeding current manufacturer recommendations for HIV VL testing. However, given the limited number of studies addressing this question, especially at low levels of viremia, additional evaluations on HIV RNA stability in EDTA tubes and PPT in field conditions are needed

Challenges and Opportunities for the Implementation of Virological Testing in resource-limited settings

Though the advantages of routine virological monitoring for patients on anti-retroviral therapy have been established, cost and complexity limit its full implementation. Monitoring is important for diagnosing virological failure early on, before the development of drug resistance mutations, and to trigger early adherence interventions. Simple and cost-effective viral load tests that facilitate simplification and decentralization of testing and strategies, such as the use of dried blood spots and pooled sample testing, which further aid simplification, are becoming available. In addition, replacing immunological monitoring with virological monitoring in non-viremic patients in a phased manner will reduce the costs associated with dual immuno-virological monitoring. Going forward, the simplification of testing paired with price reducing strategies that will allow for healthy competition between multiple manufacturers will enable the implementation of viral load testing in resource-poor settings. It is important that future HIV and AIDS treatment guidelines provide clear recommendations for routine virological monitoring and that governments and donors fund the implementation of accurate and operationally proven testing platforms in a comprehensive manner

Pooled HIV-1 Viral Load Testing Using Dried Blood Spots to Reduce the Cost of Monitoring Antiretroviral Treatment in a Resource-Limited Setting

: Rollout of routine HIV-1 viral load monitoring is hampered by high costs and logistical difficulties associated with sample collection and transport. New strategies are needed to overcome these constraints. Dried blood spots from finger pricks have been shown to be more practical than the use of plasma specimens, and pooling strategies using plasma specimens have been demonstrated to be an efficient method to reduce costs. This study found that combination of finger-prick dried blood spots and a pooling strategy is a feasible and efficient option to reduce costs, while maintaining accuracy in the context of a district hospital in Malawi

Transformando la educación virtual: La revolución de la inteligencia artificial en la potenciación de la plataforma Moodle

Los avances en la tecnología de Inteligencia Artificial (IA) y la creciente demanda en la educación en línea han impulsado la adopción de plataformas educativas, se destaca moodle como una de las principales plataformas. Se ha detectado una adaptabilidad limitada de moodle a las necesidades individuales de los estudiantes. El propósito de este artículo es explorar cómo la implementación de la IA puede potenciar moodle y transformar la experiencia de aprendizaje en línea. Se realizó una revisión sistemática de 231 artículos. Estos fueron seleccionados en base a una búsqueda en las bases de datos Scopus, Springer y Scielo, se adoptaron criterios de elegibilidad y tres preguntas de evaluación de Excel para realizar un análisis de contenido, a través de la codificación PRISMA. Como resultado se obtuvo que la educación hoy en día ofrece clases en línea con el uso de diversas herramientas tecnológicas como chatsbots virtuales, asistentes personali-zados y tutorías académicas. Finalmente, en el ámbito educativo trabajar en conjunto es fundamental para superar los obstáculos y maximizar el potencial de las herramientas basadas en IA con el fin de mejorar la calidad de las plataformas en línea.Los avances en la tecnología de inteligencia artificial (IA) y la creciente demanda en la educación en línea han impulsado la adopción de plataformas educativas, se destaca moodle como una de las principales plataformas. Se ha detectado una limitada adaptabilidad de moodle a las necesidades individuales de los estudiantes. El propósito de este artículo es explorar cómo la implementación de la IA puede potenciar esta plataforma y transformar la experiencia de aprendizaje en línea. Se realizó una revisión sistemática de 231 artículos. Estos fueron seleccionados en base a una búsqueda en las bases de datos Scopus, Springer y Scielo, se utilizó criterios de elegibilidad y tres preguntas de evaluación de Excel para realizar un análisis de contenido, a través de codificación PRISMA. Como resultado se obtuvo que la educación hoy en día ofrece clases en línea con el uso de diversas herramientas tecnológicas como chatsbots virtuales, asistentes personalizados y tutorías académicas. Finalmente, en el ámbito educativo trabajar en conjunto es fundamental para superar los obstáculos y maximizar el potencial de las herramientas basadas en IA con el fin de mejorar la calidad de las plataformas en línea

Usability and acceptability of oral fluid hepatitis C self-testing among people who inject drugs in Coastal Kenya: a cross-sectional pilot study.

BACKGROUND: People who inject drugs (PWID) are disproportionally affected by hepatitis C virus (HCV) infection and many remain undiagnosed. HCV self-testing (HCVST) may be an effective approach to increase testing uptake, but has rarely been used among PWID. We assessed the usability and acceptability of HCVST among PWID in Kenya. METHODS: We conducted a cross-sectional study nested within a cohort study between August and December 2020 on Kenya's North Coast region. Participants were handed a prototype oral fluid HCVST kit and asked to conduct the test relying on the instructions for use. Usability was assessed by documenting errors made and difficulties faced by participants. Acceptability was assessed using an interviewer-administered semi-structured questionnaire. RESULTS: Among 150 participants, 19% were female and 65.3% had primary level education or lower. 71.3% made at least one error, 56.7% experienced some difficulty during at least one step, and the majority of participants (78%) required assistance during at least one step of the procedure. Most common errors occurred when placing the tube into the stand (18%), collecting the oral fluid sample (24%) and timing of reading results (53%). There was a strong association between presence of symptoms of opiate withdrawals and observed errors (94% vs 62%; p = 0.016) in a sub-group of 74 participants assessed. Inter-reader and inter-operator concordance were 97.7% (kappa: 0.92) and 99.2% (kappa: 0.95), respectively. Acceptability assessed by asking whether participants would choose to use HCVST prior to and after conducting HCVST was 98% and 95%, respectively. CONCLUSIONS: We found a high acceptability of oral fluid HCVST among PWID. User errors were common and were associated with the presence of withdrawal symptoms among users. Despite errors, most participants were able to obtain and interpret results correctly. These findings suggest that this group of users may benefit from greater messaging and education including options to receive direct assistance when self-testing for HCV

Computer design of obligate heterodimer meganucleases allows efficient cutting of custom DNA sequences

Meganucleases cut long (>12 bp) unique sequences in genomes and can be used to induce targeted genome engineering by homologous recombination in the vicinity of their cleavage site. However, the use of natural meganucleases is limited by the repertoire of their target sequences, and considerable efforts have been made to engineer redesigned meganucleases cleaving chosen targets. Homodimeric meganucleases such as I-CreI have provided a scaffold, but can only be modified to recognize new quasi-palindromic DNA sequences, limiting their general applicability. Other groups have used dimer-interface redesign and peptide linkage to control heterodimerization between related meganucleases such as I-DmoI and I-CreI, but until now there has been no application of this aimed specifically at the scaffolds from existing combinatorial libraries of I-CreI. Here, we show that engineering meganucleases to form obligate heterodimers results in functional endonucleases that cut non-palindromic sequences. The protein design algorithm (FoldX v2.7) was used to design specific heterodimer interfaces between two meganuclease monomers, which were themselves engineered to recognize different DNA sequences. The new monomers favour functional heterodimer formation and prevent homodimer site recognition. This design massively increases the potential repertoire of DNA sequences that can be specifically targeted by designed I-CreI meganucleases and opens the way to safer targeted genome engineering

Usability and acceptability of oral-based HCV self-testing among key populations: a mixed-methods evaluation in Tbilisi, Georgia

Background: Hepatitis C virus self-testing (HCVST) is an additional approach that may expand access to HCV testing. We conducted a mixed-methods cross-sectional observational study to assess the usability and acceptability of HCVST among people who inject drugs (PWID), men who have sex with men (MSM) and transgender (TG) people in Tbilisi, Georgia. Methods: The study was conducted from December 2019 to June 2020 among PWID at one harm reduction site and among MSM/TG at one community-based organization. We used a convergent parallel mixed-methods design. Usability was assessed by observing errors made and difficulties faced by participants. Acceptability was assessed using an interviewer-administered semi-structured questionnaire. A subset of participants participated in cognitive and in-depth interviews. Results: A total of 90 PWID, 84 MSM and 6 TG were observed performing HCVST. PWID were older (median age 35 vs 24) and had a lower level of education compared to MSM/TG (27% vs 59%). The proportion of participants who completed all steps successfully without assistance was 60% among PWID and 80% among MSM/TG. The most common error was in sample collection and this was observed more often among PWID than MSM/TG (21% vs 6%; p = 0.002). More PWID requested assistance during HCVST compared to MSM/TG (22% vs 8%; p = 0.011). Acceptability was high in both groups (98% vs 96%; p = 0.407). Inter-reader agreement was 97% among PWID and 99% among MSM/TG. Qualitative data from cognitive (n = 20) and in-depth interviews (n = 20) was consistent with the quantitative data confirming a high usability and acceptability. Conclusions: HCVST was highly acceptable among key populations in Georgia of relatively high educational level, and most participants performed HCVST correctly. A significant difference in usability was observed among PWID compared to MSM/TG, indicating that PWID may benefit from improved messaging and education as well as options to receive direct assistance when self-testing for HCV