Preparation method of NZVI-PVDF hybrid films with cation-exchange function for reductive transformation of Cr(VI)

Poly (vinylidene fluoride) (PVDF) microporous film was successfully synthesized and functionalized by poly acrylic acid (PAA) for immobilization of nanoscale zero-valent iron (NZVI). PAA was innovatively introduced onto PVDF film via in situ polymerization of acrylic acid (AA) and followed by ion exchange procedure. The as-prepared PAA/PVDF-NZVI hybrids (PPN) were characterized in terms of morphology (SEM) and surface functional groups (FTIR). FTIR spectra confirms the functionalization of PVDF film by coating of PAA within its micropores. And SEM images suggested that NZVI were well immobilized onto the surface of the support. Over the reaction course, the resultant PPN hybrids demonstrated high reactivity, excellent stability and reusability for Cr(VI) removal. Results showed that lower pH and initial concentration facilitated the removal of Cr(VI) by PPN. Compared with bare NZVI, PAA/PVDF film-immobilized NZVI resulted in a lower activation energy for Cr(VI) removal, indicating that Cr(VI) reduction process with PPN is a surfacecontrolled chemical reaction. Moreover, a two-parameter pseudo-first-order model was provided and well-described the reaction kinetics of Cr(VI) over PPN under various conditions

Viral load monitoring and antiretroviral treatment outcomes in a pediatric HIV cohort in Ghana

Background: HIV-infected children in sub-Saharan Africa may be at a high risk of staying on a failing first-line regimen and developing drug-resistance HIV variants due to lack of routine viral load monitoring. We investigated whether cumulative viral load, measured as viremia copy-years (VCY) could predict morbidity in a setting where viral load is not routinely monitored. Methods: This was a single-center prospective observational longitudinal study of HIV-infected children initiating antiretroviral therapy (ART) at the Pediatric HIV/AIDS Care program at Korle-Bu Teaching Hospital in Accra, Ghana. The main outcome was morbidity measured as frequency of hospitalizations, opportunistic infections, and outpatient sick visits. The main explanatory variable was viral load measured as VCY. Results: The study included 140 children who initiated ART between September 2009 and May 2013 and had at least 2 viral load measurements. There were 184 hospitalizations, with pneumonia being the most common cause (22.8 %). A total of 102 opportunistic infections was documented, with tuberculosis being the most common opportunistic infection (68 %). A total of 823 outpatient sick visits was documented, with upper respiratory infections (14.2 %) being the most common cause. Forty-four percent of our study participants had >4 log10 VCY. Children in this sub-cohort had a higher frequency of sick visits compared with those with 4 log10 VCY had been identified as treatment failure using WHO clinical and immunological treatment failure criteria. Conclusions: High level of cumulative viral load may translate to virological failure and subsequent increased all-cause morbidity. Our finding of potential utility of VCY in pediatrics warrants further investigations. VCY may be a good alternate to routine viral load measurement as its determination may be less frequent and could be personalized to save cost

Viral load monitoring and antiretroviral treatment outcomes in a pediatric HIV cohort in Ghana

Background: HIV-infected children in sub-Saharan Africa may be at a high risk of staying on a failing first-line regimen and developing drug-resistance HIV variants due to lack of routine viral load monitoring. We investigated whether cumulative viral load, measured as viremia copy-years (VCY) could predict morbidity in a setting where viral load is not routinely monitored. Methods: This was a single-center prospective observational longitudinal study of HIV-infected children initiating antiretroviral therapy (ART) at the Pediatric HIV/AIDS Care program at Korle-Bu Teaching Hospital in Accra, Ghana. The main outcome was morbidity measured as frequency of hospitalizations, opportunistic infections, and outpatient sick visits. The main explanatory variable was viral load measured as VCY. Results: The study included 140 children who initiated ART between September 2009 and May 2013 and had at least 2 viral load measurements. There were 184 hospitalizations, with pneumonia being the most common cause (22.8 %). A total of 102 opportunistic infections was documented, with tuberculosis being the most common opportunistic infection (68 %). A total of 823 outpatient sick visits was documented, with upper respiratory infections (14.2 %) being the most common cause. Forty-four percent of our study participants had >4 log10 VCY. Children in this sub-cohort had a higher frequency of sick visits compared with those with 4 log10 VCY had been identified as treatment failure using WHO clinical and immunological treatment failure criteria. Conclusions: High level of cumulative viral load may translate to virological failure and subsequent increased all-cause morbidity. Our finding of potential utility of VCY in pediatrics warrants further investigations. VCY may be a good alternate to routine viral load measurement as its determination may be less frequent and could be personalized to save cost

Synchrotron Radiation Dominates the Extremely Bright GRB 221009A

The brightest Gamma-ray burst, GRB 221009A, has spurred numerous theoretical investigations, with particular attention paid to the origins of ultra-high energy TeV photons during the prompt phase. However, analyzing the mechanism of radiation of photons in the $\sim$MeV range has been difficult because the high flux causes pile-up and saturation effects in most GRB detectors. In this letter, we present systematic modeling of the time-resolved spectra of the GRB using unsaturated data obtained from Fermi/GBM (precursor) and SATech-01/GECAM-C (main emission and flare). Our approach incorporates the synchrotron radiation model, which assumes an expanding emission region with relativistic speed and a global magnetic field that decays with radius, and successfully fits such a model to the observational data. Our results indicate that the spectra of the burst are fully in accordance with a synchrotron origin from relativistic electrons accelerated at a large emission radius. The lack of thermal emission in the prompt emission spectra supports a Poynting-flux-dominated jet composition.Comment: 12 pages, 6 figures, 2 tables. Accepted for publication in ApJ

Healthy cities initiative in China: Progress, challenges, and the way forward

Article discusses how China implemented the first phase of its National Healthy Cities pilot program from 2016-20. Authors recommend aligning the Healthy Cities initiative in China with strategic national and global level agendas such as Healthy China 2030 and the Sustainable Development Goals (SDGs) by providing an integrative governance framework to facilitate a coherent intersectoral program to systemically improve population health

Development of aptamer based targeted reversibly attenuated probes

The targeted reversely attenuated probe (TRAP) is an aptamer-based biosensor in which the aptamer activity can be regulated by a specific nucleic acid sequence such as an mRNA. The TRAP has the potential of being developed for imaging gene expression in vivo. The central portion of the TRAP, between the aptamer and the attenuator, is complementary to a target nucleic acid, such as an mRNA, which is referred to as a regulatory nucleic acid (regDNA);I developed 8att-cmRas20 and 9att-cmRas15 ATP DNA TRAPs with regDNA-dependent aptamer activity. The results suggested that, as well as inhibiting the aptamer, the attenuator also acted as a structural guide, much like a chaperone, to promote proper folding of the TRAP such that it can be fully activated by the regDNA. We also showed that activation of the aptamer in the TRAP at physiological temperatures by a regDNA complementary to the intervening sequence was sensitive to single base mismatches;I then utilized a tiled microarray to identify the regions on the mRNA that can be easily targeted by antisense oligonucleotides and the results showed that the microarray approach provided a better match with the in vivo antisense than computational analysis;Selected from a microarray study, the 20nt antisense oligonucleotide that targets positions 741-750 of Lcn2 mRNA was chosen for the malachite green (MG) RNA TRAP. To develop the probe, the structure of the 38nt MG RNA aptamer was first destabilized by introducing truncations and mutations. By rational design and after screening different MG RNA TRAPs, the aptamer activity of an TRAP that consists of a 32nt modified MG RNA aptamer and 9nt attenuator sequence was shown to be increased about 20-fold in the presence of a 20nt regDNA;A yeast selection system has been designed to test the function in vivo of the selected TRAP. A hammerhead (HH) ribozyme - aptamer/TRAP - hepatitis Delta Virus (HDV) ribozyme cassette was constructed to produce aptamers or TRAPs with defined and homogeneous 5' and 3' ends.</p