Amorphisation and recrystallisation study of lithium intercalation into TiO 2 nano-architecture.

Titanium dioxide is playing an increasingly significant role in easing environmental and energy concerns. Its rich variety of polymorphic crystal structures has facilitated a wide range of applications such as photo-catalysis, photo-splitting of water, photoelectrochromic devices, insulators in metal oxide, semiconductors devices, dye sensitized solar cells (DSSCs) (energy conversions), rechargeable lithium batteries (electrochemical storage). The complex structural aspects in nano TiO 2 , are elucidated by microscopic visualization and quantification of the microstructure for electrode materials, since cell performance and various aging mechanisms depend strongly on the appearance and changes in the microstructure. Recent studies on MnO 2 have demonstrated that amorphisation and recrystallisation simulation method can adequately generate various nanostructures, for Li-ion battery compounds. The method was also previously employed to produce nano-TiO 2 . In the current study, the approach is used to study lithiated nanoporous structure for TiO 2 which have been extensively studied experimentally, as mentioned above. Molecular graphic images showing microstructural features, including voids and channels have accommodated lithium’s during lithiation and delithiation. Preliminary lithiation of TiO 2 will be considered

Amorphisation and recrystallisation study of lithium intercalation into TiO 2 nano-architecture.

Titanium dioxide is playing an increasingly significant role in easing environmental and energy concerns. Its rich variety of polymorphic crystal structures has facilitated a wide range of applications such as photo-catalysis, photo-splitting of water, photoelectrochromic devices, insulators in metal oxide, semiconductors devices, dye sensitized solar cells (DSSCs) (energy conversions), rechargeable lithium batteries (electrochemical storage). The complex structural aspects in nano TiO 2 , are elucidated by microscopic visualization and quantification of the microstructure for electrode materials, since cell performance and various aging mechanisms depend strongly on the appearance and changes in the microstructure. Recent studies on MnO 2 have demonstrated that amorphisation and recrystallisation simulation method can adequately generate various nanostructures, for Li-ion battery compounds. The method was also previously employed to produce nano-TiO 2 . In the current study, the approach is used to study lithiated nanoporous structure for TiO 2 which have been extensively studied experimentally, as mentioned above. Molecular graphic images showing microstructural features, including voids and channels have accommodated lithium’s during lithiation and delithiation. Preliminary lithiation of TiO 2 will be considered

Growth and CD4 patterns of adolescents living with perinatally acquired HIV worldwide, a CIPHER cohort collaboration analysis

Introduction: Adolescents living with HIV are subject to multiple co-morbidities, including growth retardation and immunodeficiency. We describe growth and CD4 evolution during adolescence using data from the Collaborative Initiative for Paediatric HIV Education and Research (CIPHER) global project. Methods: Data were collected between 1994 and 2015 from 11 CIPHER networks worldwide. Adolescents with perinatally acquired HIV infection (APH) who initiated antiretroviral therapy (ART) before age 10 years, with at least one height or CD4 count measurement while aged 10–17 years, were included. Growth was measured using height-for-age Z-scores (HAZ, stunting if <-2 SD, WHO growth charts). Linear mixed-effects models were used to study the evolution of each outcome between ages 10 and 17. For growth, sex-specific models with fractional polynomials were used to model non-linear relationships for age at ART initiation, HAZ at age 10 and time, defined as current age from 10 to 17 years of age. Results: A total of 20,939 and 19,557 APH were included for the growth and CD4 analyses, respectively. Half were females, two-thirds lived in East and Southern Africa, and median age at ART initiation ranged from <3 years in North America and Europe to >7 years in sub-Saharan African regions. At age 10, stunting ranged from 6% in North America and Europe to 39% in the Asia-Pacific; 19% overall had CD4 counts <500 cells/mm3. Across adolescence, higher HAZ was observed in females and among those in high-income countries. APH with stunting at age 10 and those with late ART initiation (after age 5) had the largest HAZ gains during adolescence, but these gains were insufficient to catch-up with non-stunted, early ART-treated adolescents. From age 10 to 16 years, mean CD4 counts declined from 768 to 607 cells/mm3. This decline was observed across all regions, in males and females. Conclusions: Growth patterns during adolescence differed substantially by sex and region, while CD4 patterns were similar, with an observed CD4 decline that needs further investigation. Early diagnosis and timely initiation of treatment in early childhood to prevent growth retardation and immunodeficiency are critical to improving APH growth and CD4 outcomes by the time they reach adulthood

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Growth and CD4 patterns of adolescents living with perinatally acquired HIV worldwide, a CIPHER cohort collaboration analysis

INTRODUCTION: Adolescents living with HIV are subject to multiple co-morbidities, including growth retardation and immunodeficiency. We describe growth and CD4 evolution during adolescence using data from the Collaborative Initiative for Paediatric HIV Education and Research (CIPHER) global project. METHODS: Data were collected between 1994 and 2015 from 11 CIPHER networks worldwide. Adolescents with perinatally acquired HIV infection (APH) who initiated antiretroviral therapy (ART) before age 10 years, with at least one height or CD4 count measurement while aged 10-17 years, were included. Growth was measured using height-for-age Z-scores (HAZ, stunting if 7 years in sub-Saharan African regions. At age 10, stunting ranged from 6% in North America and Europe to 39% in the Asia-Pacific; 19% overall had CD4 counts <500 cells/mm3 . Across adolescence, higher HAZ was observed in females and among those in high-income countries. APH with stunting at age 10 and those with late ART initiation (after age 5) had the largest HAZ gains during adolescence, but these gains were insufficient to catch-up with non-stunted, early ART-treated adolescents. From age 10 to 16 years, mean CD4 counts declined from 768 to 607 cells/mm3 . This decline was observed across all regions, in males and females. CONCLUSIONS: Growth patterns during adolescence differed substantially by sex and region, while CD4 patterns were similar, with an observed CD4 decline that needs further investigation. Early diagnosis and timely initiation of treatment in early childhood to prevent growth retardation and immunodeficiency are critical to improving APH growth and CD4 outcomes by the time they reach adulthood

Outcomes of second‐line antiretroviral therapy among children living with HIV: a global cohort analysis

INTRODUCTION: Limited data describe outcomes on second‐line antiretroviral therapy (ART) among children globally. Our objective was to contribute data on outcomes among children living with HIV after initiation of second‐line ART in the context of routine care within a large global cohort collaboration. METHODS: Patient‐level data from 1993 through 2015 from 11 paediatric HIV cohorts were pooled. Characteristics at switch and through two years of follow‐up were summarized for children who switched to second‐line ART after starting a standard first‐line regimen in North America, Latin America, Europe, Asia, Southern Africa (South Africa & Botswana) and the rest of sub‐Saharan Africa (SSA). Cumulative incidences of mortality and loss to follow‐up (LTFU) were estimated using a competing risks framework. RESULTS: Of the 85,389 children on first‐line ART, 3,555 (4%) switched to second‐line after a median of 2.8 years on ART (IQR: 1.6, 4.7); 69% were from Southern Africa or SSA and 86% of second‐line regimens were protease inhibitor‐based. At switch, median age was 8.4 years and 50% had a prior AIDS diagnosis. Median follow‐up after switch to second‐line ranged from 1.8 years in SSA to 5.3 years in North America. Median CD4 counts at switch to second‐line ranged from 235 cells/mm^{3} in SSA to 828 cells/mm^{3} in North America. Improvements in CD4 counts were observed over two years of follow‐up, particularly in regions with lower CD4 counts at second‐line switch. Improvements in weight‐for‐age z‐scores were not observed during follow‐up. Cumulative incidence of LTFU at two years was <5% in all regions except SSA (7.1%) and Southern Africa (7.4%). Risk of mortality was <3% at two years of follow‐up in all regions, except Latin America (4.9%) and SSA (5.5%). CONCLUSIONS: Children switched to second‐line ART experience CD4 count increases as well as low to moderate rates of LTFU and mortality within two years after switch. Severe immune deficiency at time of switch in some settings suggests need for improved recognition and management of treatment failure in children