Polyphosphazene-Based Anion-Anchored Polymer Electrolytes For All-Solid-State Lithium Metal Batteries.

Safety concerns of traditional liquid electrolytes, especially when paired with lithium (Li) metal anodes, have stimulated research of solid polymer electrolytes (SPEs) to exploit the superior thermal and mechanical properties of polymers. Polyphosphazenes are primarily known for their use as flame retardant materials and have demonstrated high Li-ion conductivity owing to their highly flexible P = N backbone which promotes Li-ion conduction via inter- and intrachain hopping along the polymer backbone. While polyphosphazenes are largely unexplored as SPEs in the literature, a few existing examples showed promising ionic conductivity. By anchoring the anion to the polymer backbone, one may primarily allow the movement of Li ions, alleviating the detrimental effects of polarization that are common in conventional dual-ion conducting SPEs. Anion-anchored SPEs, known as single Li-ion conducting solid polymer electrolytes (SLiC-SPEs), exhibit high Li-ion transference numbers (tLi+), which limits Li dendrite growth, thus further increasing the safety of SPEs. However, previously reported SLiC-SPEs suffer from inadequate ionic conductivity, small electrochemical stability windows (ESWs), and limited cycling stability. Herein, we report three polyphosphazene-based SLiC-SPEs comprising lithiated polyphosphazenes. The SLiC polyphosphazenes were prepared through a facile synthesis route, opening the door for enhanced tunability of polymer properties via facile macromolecular nucleophilic substitution and subsequent lithiation. State-of-the-art characterization techniques, such as differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), and solid-state nuclear magnetic resonance spectroscopy (ssNMR) were employed to probe the effect of the polymer structure on Li-ion dynamics and other electrochemical properties. Produced SPEs showed thermal stability up to ∼208 °C with ionic conductivities comparable to that of the best-reported SLiC-SPEs that definitively comprise no solvents or plasticizers. Among the three lithiated polyphosphazenes, the SPE containing dilithium poly[bis(trifluoroethylamino)phosphazene] (pTFAP2Li) exhibited the most promising electrochemical characteristics with tLi+ of 0.76 and compatibility with both Li metal anodes and LiFePO4 (LFP) cathodes; through 40 cycles at 100 °C, the PEO-pTFAP2Li blend showed 81.2% capacity utilization and 86.8% capacity retention. This work constitutes one of the first successful demonstrations of the cycling performance of a true all-solid-state Li-metal battery using SLiC polyphosphazene SPEs.

Pregnancy, pregnancy outcomes, and infant growth and development after recovery from Ebola virus disease in Liberia: an observational cohort study.

BACKGROUND: Minimal data exist on pregnancy following recovery from Ebola in people of child-bearing potential (females aged roughly 18-45 years). The aim of this study was to assess viral persistence or reactivation in pregnancy, the frequency of placental transfer of anti-Ebola IgG antibodies, and pregnancy outcomes in this population. METHODS: In this observational cohort study, we studied self-reported pregnancies in two groups: seropositive people who had recovered from Ebola virus disease (seropositive group) and seronegative people who had close contact with people with Ebola (seronegative group). Participants had enrolled in the PREVAIL III longitudinal study and were exposed during the 2014-2016 Liberian Ebola outbreak. The primary outcome was pregnancy result. We assessed rates of livebirths and other pregnancy results in both study groups, and presence of Ebola RNA by PCR in samples of placenta, maternal and cord blood, breastmilk, and vaginal secretions from people who had recovered from Ebola who conceived a median of 14 months after acute Ebola virus disease. Mixed-model logistic regression evaluated associations between first-reported pregnancy outcome, age, and study group. Growth and neurodevelopment in the infants born to people in the seropositive group were assessed at 6-month intervals for 2 years. Data were accrued by PREVAIL III study staff. FINDINGS: 1566 participants were enrolled between June 17, 2015, and Dec 14, 2017, of whom 639 became pregnant (215 seropositive, 424 seronegative) and 589 reported pregnancy outcomes (206 seropositive, 383 seronegative). 105 infants born to 98 mothers in the seropositive group were enrolled in the birth cohort. Ebola RNA was not detected in 205 samples of placenta, cord blood, or maternal blood taken at birth from 54 mothers in the seropositive group, nor in 367 vaginal swabs. Viral RNA was found in two of 354 longitudinal breastmilk samples. All but one of 57 infants born during these 54 births were seropositive for anti-Ebola antibodies. Neonates showed high concentrations of anti-Ebola IgG, which declined after 6 months. Odds of adverse pregnancy outcome among the two groups were indistinguishable (OR 1·13, 95% CI 0·71-1·79). Compared with WHO standards, infants born to those in the seropositive group had lower median weight and length, and larger median head circumference over 2 years. Compared with a cohort from the USA accrual of gross motor developmental milestones was similar, whereas attainment of pincer grasp and early vocalisation were mildly delayed. INTERPRETATION: The risks of Ebola virus reactivation in the peripartum and postpartum period and of adverse birth outcomes are low in those who have recovered from Ebola virus disease and become pregnant approximately 1 year after acute Ebola virus disease. The implication for clinical practice is that care of people who are pregnant and who have recovered from Ebola can be offered without risks to health-care providers or stigmatisation of the mothers and their offspring. The implication for prospective mothers is that safe pregnancies are entirely possible after recovery from Ebola. FUNDING: National Institute of Allergy and Infectious Diseases and Liberia Ministry of Health.

Nanodiamond-Enhanced Nanofiber Separators for High-Energy Lithium-Ion Batteries.

Current lithium-ion battery separators made from polyolefins such as polypropylene and polyethylene generally suffer from low porosity, low wettability, and slow ionic conductivity and tend to perform poorly against heat-triggering reactions that may cause potentially catastrophic issues, such as fire. To overcome these limitations, here we report that a porous composite membrane consisting of poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers functionalized with nanodiamonds (NDs) can realize a thermally resistant, mechanically robust, and ionically conductive separator. We critically reveal the role of NDs in the polymer matrix of the membrane to improve the thermal, mechanical, crystalline, and electrochemical properties of the composites. Taking advantages of these characteristics, the ND-functionalized nanofiber separator enables high-capacity and stable cycling of lithium cells with LiNi0.8Mn0.1Co0.1O2 (NMC811) as the cathode, much superior to those using conventional polyolefin separators in otherwise identical cells.

Hypertensive Disorders in Pregnancy at the John F. Kennedy Maternity Center (JFKMC), Liberia: Burden, Sub-Types, and Maternofetal Outcome.

Background: Hypertensive disorders in pregnancy (HDP) are a leading cause of maternal and fetal death, especially in a resource-constrained setting. There is no study from Liberia on the disorder. This pilot study aimed to determine the burden, sub-types, and maternal-fetal outcomes of hypertensive disorders in pregnancy at the John F. Kennedy Maternity Center (JFKMC), Liberia. Methods: From January 1 to December 31, 2020, the medical records of 130 pregnant and post-partum patients admitted with Hypertensive disorders in pregnancy (HDP) in a census method of sampling were retrieved, while 83.1% (108) were suitable for analysis in an institutional cross-sectional retrospective study in the department of obstetrics and gynecology at the John F. Kennedy Maternity Center, Liberia. The extracted information was analyzed using SPSS version 26. Results were presented in frequencies and percentages. The statistical association between categorical variables was subjected to the Chi-square test. The level of significance was set at a P-value of < 0.05. Results: There was an institutional prevalence of 3.0% of HDP. The maternal fatality rate was 12.3%, while the perinatal fatality rate was 14.3%. There was a significant association between HELLP syndrome and Severe pre-eclampsia with maternal death, P< 0.001. Prematurity, first minutes Apgar score <5, NICU admission, and low birth weight were associated with perinatal deaths (P <0.001). Conclusion: HDP was an important contributor to maternal and perinatal deaths at the JFKMC, Liberia. Continuous support by the government and development partners for the provision of critical life-saving medical equipment at the JFKMC is recommended.

Community-Institutional Partnerships to Strengthen Maternal Health Care: Case Study of the First Obstetrics and Gynecology Specialty Training Program in Liberia.

Despite major setbacks to its health infrastructure and health workforce capacity, Liberia began its first post-graduate training program for physicians in 2013. Specialty training in Internal Medicine, Pediatrics, General Surgery and Obstetrics and Gynecology were the four inaugural Residency programs that recruited graduates from the country's only medical school, A.M. Dogliotti College of Medicine. The Obstetrics and Gynecology residency program was designed to combat the rising maternal mortality and strengthen health systems to improve maternal care. The program adapted in the face of challenges posed by limited financial support, lack of specialist-faculty and general physician shortages and the Ebola virus outbreak. The manuscript discusses the challenges and successes of the program and demonstrates how the shortage of teaching faculty was addressed by developing a collaboration between local government and educational communities, a United States (US) academic institution and volunteers from the Global Health Service Partnership.

A combined case of amelia and phocomelia in a neonate, at JFK Maternity Center, Liberia.

We report a case of spontaneous rare birth deformity. A case of Amelia and Phocomelia in a neonate. Amelia is a rare congenital disorder, even more so, is the combined amelia and phocomelia in a neonate. True Phocomelia was defined as the total absence of the intermediate segments of the limb. With the hand or foot (normal, almost normal, or malformed), directly attached to the trunk. The common aetiological association with phocomelia is from the use of thalidomide and genetic inheritance, as an autosomal recessive trait, involving chromosome 8. Isolated amelia is not generally considered to be of genetic origin. We present a neonate delivered by a 28-years multipara in Liberia, in West Africa Sub-Region, with amelia involving the two upper limbs, right lower limb and a Phocomelia involving the left lower limb (absence of tibia and fibula and feet with three toes). Africa is the only continent not included in the International Clearinghouse for Birth Defects Surveillance and Research. It is hoped that case reports of congenital limb deformities from Africa, will contribute to the formation of a database for birth defects shortly. Funding: None declared.

Novel use of fine needle aspiration (FNA) biopsy to diagnose cervical cancer in a low-resource setting: A case series Morovia, Liberia.

The role of pathology in improving cancer in resource-limited countries is essential, yet many barriers exist. FNA is a rapid, low-cost and efficient method for diagnosing cancer, planning treatment, and building a cancer registry.

Low flows and downstream decline in phytoplankton contribute to impaired water quality in the lower Minnesota River.

The underlying physical and biogeochemical mechanisms associated with low dissolved oxygen (DO) levels below 5 mg L-1 were examined through field data analyses and water quality modeling of the lower 40 miles of the Minnesota River. Insights into flow and water quality data of nineteen years (1999-2017) at five sites demonstrate that low DO levels parallel the obvious longitudinal (upstream-to-downstream) decline in phytoplankton biomass and increase in ammonium nitrogen (NH4) and dissolved orthophosphate (PO4) in the last 22-mile river reach (i.e., navigation channel) during late summer low flow conditions. River discharge is inversely related to the magnitude of the longitudinal change in DO, phytoplankton biomass, NH4 and PO4, indicating that the late summer low flow hydrodynamics in the navigation channel with a longer residence time, deeper water and slower velocity provide an extended opportunity for the biogeochemical reactions involving phytoplankton, DO and nutrients. Moreover, the ratio of the longitudinal decline in DO versus the longitudinal increase in NH4 is particularly close to the Redfield O:N ratio, suggesting that the decline in DO and increase in nutrients most likely result from the decomposition of phytoplankton detritus under aerobic conditions. This is further proved by the water quality modeling of the lower Minnesota River. The primary reasons for impaired water quality are substantially elevated sediment oxygen consumption and nutrient release derived from the decomposition of settled phytoplankton detritus in the navigation channel. Therefore, we recommend that active prevention of abrupt phytoplankton blooms and collapses through regulation of river discharge and local hydrodynamics may assist in maintaining acceptable water quality in eutrophic rivers with a high level of phytoplankton biomass.

High-Capacity and Rapid Removal of Refractory NOM Using Nanoscale Anion Exchange Resin.

As human health concerns over disinfection byproducts (DBP) in drinking water increase, so does the need to develop new materials that remove them rapidly and at high capacity. Ion exchange (IEX) is an effective method for the removal of natural organic matter (NOM), especially anion exchange resins (AERs) with quaternary ammonium functional groups. However, capacity is limited in existing commercial resin materials because adsorbates can only interact with the outermost surface area, which makes these products inefficient on a mass basis. We have synthesized a novel "NanoResin" exploiting the enhanced NOM removal of the quaternary ammonium resin while utilizing the vast surface area of SWCNTs, which act as scaffolding for the resin. Our nanomaterials show increased adsorption capacity compared to commercially available adsorbents, in a fraction of the time. This NanoResin requires only about 10 s to reach ion-exchange equilibrium. Comparatively, commercial AERs only achieved partial removal after more than 30 min. High capacity adsorption of a low molecular weight (MW) surrogate has been measured. NOM removal was demonstrated in solutions of both low and high specific UV absorbance (SUVA) composition with these nanomaterials. Additionally, the NanoResin showed enhanced removal of a NOM concentrate sample taken from Myrtle Beach, SC, demonstrating NanoResin is an effective method of removal for refractory NOM in a natural aqueous environment. Synthesis and characterization of the polymers and nanomaterials are presented below. Adsorption capacity, adsorption kinetics, and the regeneration and reusability of these new materials for NOM removal are described. The open matrix microstructure precludes any intraparticle diffusion of adsorbates; thus, these nanomaterials act as a "contact resin".

Application of TREECS Modeling System to Strontium-90 for Borschi Watershed near Chernobyl, Ukraine.

The Training Range Environmental Evaluation and Characterization System (TREECS™) (http://el.erdc.usace.army.mil/treecs/) is being developed by the U.S. Army Engineer Research and Development Center (ERDC) for the U.S. Army to forecast the fate of munitions constituents (MC) (such as high explosives (HE) and metals) found on firing/training ranges, as well as those subsequently transported to surface water and groundwater. The overall purpose of TREECS™ is to provide environmental specialists with tools to assess the potential for MC migration into surface water and groundwater systems and to assess range management strategies to ensure protection of human health and the environment. The multimedia fate/transport models within TREECS™ are mathematical models of reduced form (e.g., reduced dimensionality) that allow rapid application with less input data requirements compared with more complicated models. Although TREECS™ was developed for the fate of MC from military ranges, it has general applicability to many other situations requiring prediction of contaminant (including radionuclide) fate in multi-media environmental systems. TREECS™ was applied to the Borschi watershed near the Chernobyl Nuclear Power Plant, Ukraine. At this site, TREECS™ demonstrated its use as a modeling tool to predict the fate of strontium 90 ((90)Sr). The most sensitive and uncertain input for this application was the soil-water partitioning distribution coefficient (Kd) for (90)Sr. The TREECS™ soil model provided reasonable estimates of the surface water export flux of (90)Sr from the Borschi watershed when using a Kd for (90)Sr of 200 L/kg. The computed export for the year 2000 was 0.18% of the watershed inventory of (90)Sr compared to the estimated export flux of 0.14% based on field data collected during 1999-2001. The model indicated that assumptions regarding the form of the inventory, whether dissolved or in solid phase form, did not appreciably affect export rates. Also, the percentage of non-exchangeable adsorbed (90)Sr, which is uncertain and affects the amount of (90)Sr available for export, was fixed at 20% based on field data measurements. A Monte Carlo uncertainty analysis was conducted treating Kd as an uncertain input variable with a range of 100-300 L/kg. This analysis resulted in a range of 0.13-0.27% of inventory exported to surface water compared to 0.14% based on measured field data. Based on this model application, it was concluded that the export of (90)Sr from the Borschi watershed to surface water is predominantly a result of soil pore water containing dissolved (90)Sr being diverted to surface waters that eventually flow out of the watershed. The percentage of non-exchangeable adsorbed (90)Sr and the soil-water Kd are the two most sensitive and uncertain factors affecting the amount of export. The 200-year projections of the model showed an exponential decline in (90)Sr export fluxes from the watershed that should drop by a factor of 10 by the year 2100. This presentation will focus on TREECS capabilities and the case study done for the Borschi Watershed.

Healthcare utilisation and empowerment among women in Liberia.

BACKGROUND: Many efforts have been undertaken to improve access to healthcare services in low-income settings; nevertheless, underutilisation persists. Women's lack of empowerment may be a central reason for underutilisation, but empirical literature establishing this relationship is sparse. METHODS: We conducted a cross-sectional study using data from the 2007 Liberia Demographic and Health Survey. Our sample included all non-pregnant women who were currently married or living with a partner (N=3925 unweighted). We used multivariate logistic regression to assess the associations between constructs derived from the Theory of Gender and Power (TGP) and healthcare utilisation. RESULTS: Two-thirds of women (65.6%) had been to a healthcare facility for herself or her children in the past 12 months. Constructs from the three major theoretical structures were associated with healthcare utilisation. Women with no education, compared with women with some education, were less likely to have been to a healthcare facility (OR=0.76; 95% CI 0.62 to 0.93) as were women who had experienced sexual abuse (OR=0.65; 95% CI 0.45 to 0.95) and women who were married (OR=0.69, 95% CI 0.54 to 0.88). Women in higher wealth quintiles, compared with women in the next lower wealth quintile, and women with more decision-making power had greater odds of having been to a healthcare facility (OR=1.22; 95% CI 1.10 to 1.36 and OR=1.10; 95% CI 1.01 to 1.20; respectively). CONCLUSIONS: Strong associations exist between healthcare utilisation and empowerment among women in Liberia, and gender imbalances are prevalent. This fundamental issue likely needs to be addressed before large-scale improvement in health service utilisation can be expected.