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Solvent structures that surround active sites reorganize during catalysis and influence the stability of surface intermediates. Within zeolite pores, H 2 O molecules form hydrogen-bonded structures that differ substantially from bulk H 2 O. Here, we show by spectroscopic measurements and molecular dynamics simulations that H 2 O molecules form bulk-like three-dimensional structures within 1.3 nm cages, whereas H 2 O molecules coalesce into oligomeric one-dimensional chains when the pore diameter falls below 0.65 nm. The differences between these solvent structure motifs provide opportunities to manipulate enthalpy–entropy compensation relationships and greatly increase the rates of catalysis. We describe how the reorganization of these pore-size-dependent H 2 O structures during alkene epoxidation catalysis gives rise to entropy gains that increase the turnover rates by up to 400-fold. Collectively, this work shows that solvent molecules form distinct structures with a highly correlated motion within microporous environments, and the reorganization of these structures may be controlled to confer stability to the desired reactive intermediates. Solvent structuring affects the energy landscape of catalytic reactions, but the quantitative understanding of such effects remains difficult. Now, the structure of water within the micropores of different zeolites is disclosed together with the effects that its reorganization has over alkene epoxidation catalysis.

To better elucidate epigenetic mechanisms that correlate with the dynamic gene expression program observed upon T-cell differentiation, we investigated the genomic landscape of histone modifications in naive and memory CD8＋ T cells. Using a ChlP-Seq approach coupled with global gene expression profiling, we generated genome-wide histone H3 lysine 4 （H3K4me3） and H3 lysine 27 （H3K27me3） trimethylation maps in naive, T memory stem cells, central memory cells, and effector memory cells in order to gain insight into how histone architecture is remodeled during T cell differentiation. We show that H3K4me3 histone modifications are associated with activation of genes, while H3K27me3 is negatively correlated with gene expression at canonical loci and enhancers associated with T-cell metabolism, effector function, and memory. Our results also reveal histone modifications and gene expression signatures that distinguish the recently identified T memory stem cells from other CD8＋ T-cell subsets. Taken together, our results suggest that CD8＋ lymphocytes undergo chromatin remodeling in a progressive fashion. These findings have major implications for our understanding of peripheral T-cell ontogeny and the formation of immunological memory.

A family of sulfated metal oxides (SMOs); sulfated zirconia (ZrS), sulfated alumina (AlS), sulfated stannia (SnS), sulfated iron oxide (FeS), sulfated titanium dioxide (TiS), and sulfated hafnia (HfS) has been synthesized and examined as support materials/cocatalysts/activators for organozirconium molecule-based olefin polymerization and hydrogenation catalysis. 13C CPMAS NMR spectroscopic analysis of Cp2Zr(13CH3) 2/SMO and (Me5Cp)2Zr(13CH 3)2/SMO chemisorption shows that highly electrophilic zirconocenium species are formed along with varying amounts of catalytically-inactive μ-oxo (Cp2Zr(CH3)O-surface) species, depending on the support material. In contrast, chemisorption of (Me5Cp)2Zr( 13CH3)2 on dehydroxylated alumina (DA) yields a similar cation via methide transfer to surface Lewis acid sites, while chemisorption onto dehydroxylated silica yields a μ-oxo Cp′ 2Zr(13CH3)-OSi≡ species. Ethylene polymerization data with the supported catalysts show that polymerization activity is dependent on both precursor ligation [complexes with greater coordinative unsaturation such as Zr(CH2Ph)4 > (Me5Cp)ZrMe 3 > coordinatively saturated complexes such as Cp2Zr(CH 3)2] and the nature of the support (ZrS > AlS > SnS > FeS > TiS) for ethylene homopolymerization at 150 psi C2H4, 60°C. Under identical conditions, the polymerization rate for (Me 5Cp)ZrMe3/DA is ∼1/10 that for (Me5Cp)ZrMe 3/AlS. In no case were active catalysts derived by chemisorbing Zr hydrocarbyl complexes on HfS. Propylene homopolymerization was also studied for Zr hydrocarbyls supported on ZrS in slurry polymerizations in liquid propylene at 20°C. Relative homopolymerization rates are: Zr(CH2Ph) 4/ZrS > Zr(CH2TMS)4/ZrS > Zr(CH2 tBu)4/ZrS >> (Me5Cp)ZrMe3/ZrS ≈ 0. The catalyst (Me5Cp)ZrMe3/AlS mediates benzene hydrogenation with a turnover frequency of 360 h−1 at 25°C/1.0 atm H2, second only to (Me5Cp)ZrMe 3/ZrS among this series of catalysts. Catalysts synthesized by chemisorbing (Me5Cp)ZrMe3 on SnS, FeS and TiS are also active for benzene hydrogenation and are readily separable from liquid phase products using physical or, in the case of FeS, magnetic techniques. Two complementary active site kinetic assays for benzene hydrogenation show that, unlike typical heterogeneous and supported organometallic catalysts, 97 ± 2% of all (Me5Cp)ZrMe3/AlS sites are catalytically significant, demonstrating that the species identified by 13C CPMAS NMR is indeed the active species. Active site assays were also conducted for ethylene polymerization mediated by (Me5Cp)ZrMe3 supported on each SMO, and reveal that 87 ± 2% of (Me5Cp)ZrMe3/AlS sites are catalytically active, again demonstrating that nearly all zirconium sites are catalytically significant. Additionally, for (Me5Cp)ZrMe3/SnS, 61 ± 5% of the Zr sites are catalytically-significant, while for (Me 5Cp)ZrMe3/FeS this quantity is 22 ± 2%, and for (Me 5Cp)ZrMe3/TiS, 63 ± 9%. In addition, the sulfated tin oxide particles have crystallite sizes of ∼5 nm and were used as effective supports for homogeneous zirconium hydrocarbyl olefin polymerization and arene hydrogenation catalysts.

In a prospective study, 498 single faecal samples from children aged under 16 years attending an outpatient clinic in the Angkor Hospital for Children, northwest Cambodia, were examined for Cryptosporidium oocysts and Giardia cysts using microscopy and molecular assays. Cryptosporidium oocysts were detected in 2.2% (11/498) of samples using microscopy and in 7.7% (38/498) with molecular tests. Giardia duodenalis cysts were detected in 18.9% (94/498) by microscopy and 27.7% (138/498) by molecular tests; 82% of the positive samples (by either method) were from children aged 1-10 years. Cryptosporidium hominis was the most common species of Cryptosporidium, detected in 13 (34.2%) samples, followed by Cryptosporidium meleagridis in 9 (23.7%), Cryptosporidium parvum in 8 (21.1%), Cryptosporidium canis in 5 (13.2%), and Cryptosporidium suis and Cryptosporidium ubiquitum in one sample each. Cryptosporidium hominis and C. parvum positive samples were subtyped by sequencing the GP60 gene: C. hominis IaA16R6 and C. parvum IIeA7G1 were the most abundant subtypes. Giardia duodenalis was typed using a multiplex real-time PCR targeting assemblages A and B. Assemblage B (106; 76.8% of all Giardia positive samples) was most common followed by A (12.3%) and mixed infections (5.1%). Risk factors associated with Cryptosporidium were malnutrition (AOR 9.63, 95% CI 1.67-55.46), chronic medical diagnoses (AOR 4.51, 95% CI 1.79-11.34) and the presence of birds in the household (AOR 2.99, 95% CI 1.16-7.73); specifically C. hominis (p = 0.03) and C. meleagridis (p<0.001) were associated with the presence of birds. The use of soap was protective against Giardia infection (OR 0.74, 95% CI 0.58-0.95). This is the first report to describe the different Cryptosporidium species and subtypes and Giardia duodenalis assemblages in Cambodian children. The variety of Cryptosporidium species detected indicates both anthroponotic and zoonotic transmission in this population. Interventions to improve sanitation, increase hand washing after defecation and before preparing food and promote drinking boiled water may reduce the burden of these two parasites.

SARS-CoV-2 lineage B.1.1.7, a variant that was first detected in the UK in September 2020 1 , has spread to multiple countries worldwide. Several studies have established that B.1.1.7 is more transmissible than pre-existing variants, but have not identified whether it leads to any change in disease severity 2 . Here we analyse a dataset that links 2,245,263 positive SARS-CoV-2 community tests and 17,452 deaths associated with COVID-19 in England from 1 November 2020 to 14 February 2021. For 1,146,534 (51%) of these tests, the presence or absence of B.1.1.7 can be identified because mutations in this lineage prevent PCR amplification of the spike ( S ) gene target (known as S gene target failure (SGTF) 1 ). On the basis of 4,945 deaths with known SGTF status, we estimate that the hazard of death associated with SGTF is 55% (95% confidence interval, 39–72%) higher than in cases without SGTF after adjustment for age, sex, ethnicity, deprivation, residence in a care home, the local authority of residence and test date. This corresponds to the absolute risk of death for a 55–69-year-old man increasing from 0.6% to 0.9% (95% confidence interval, 0.8–1.0%) within 28 days of a positive test in the community. Correcting for misclassification of SGTF and missingness in SGTF status, we estimate that the hazard of death associated with B.1.1.7 is 61% (42–82%) higher than with pre-existing variants. Our analysis suggests that B.1.1.7 is not only more transmissible than pre-existing SARS-CoV-2 variants, but may also cause more severe illness. Analysis of community-tested cases of SARS-CoV-2 indicates that the B.1.1.7 variant is not only more transmissible than pre-existing variants, but may also cause more severe illness, and is associated with a higher risk of death.

In the Greater Mekong Sub-region (GMS), malaria elimination efforts are targeting the asymptomatic parasite reservoirs. Understanding community perceptions about asymptomatic malaria infections and interventions that target this reservoir is critical to the design of community engagement. This article examines knowledge, attitudes, perceptions and practices related to asymptomatic malaria infections and mass drug administration (MDA) in malaria-endemic villages in southern Savannakhet Province, Laos. A questionnaire consisting of questions on socio-demographic characteristics, knowledge, attitudes, perceptions and practices on malaria and MDA was administered to each household head or representative (n = 281) in four villages. These topics were also further discussed in 12 single-gender focus group discussions (FGDs). The FGDs were conducted in all four villages and consisted of eight to 10 participants. A minority (14.2%; 40/281) of respondents agreed that a seemingly healthy person could have malaria parasite in his or her blood. Half (52%; 146/281) disagreed and one third (33.8%, 95/281) were unsure. Respondents who responded that \"MDA aims to cure everyone\" [AOR = 4.6; CI: 1.6-13.1], \"MDA is to make our community malaria free\" [AOR = 3.3; CI: 1.3-8.1] and \"I will take part in future MDA\" [AOR = 9.9; CI: 1.2-78.8] were more likely to accept the idea of asymptomatic malaria. During FGDs, respondents recalled signs and symptoms of malaria (fever, chills and headache), and described malaria as a major health problem. Symptomatic and asymptomatic malaria infections were associated with their work in the forest and living conditions. Measures described to eliminate malaria included using mosquito nets, wearing long-sleeved clothes and taking medicine when symptomatic. Most respondents were unaware of MDA as a tool to eliminate malaria. Awareness of asymptomatic malaria infections, and MDA as a tool to eliminate malaria, was low. With the need to target asymptomatic malaria carriers for elimination efforts in the GMS, as well as informing target groups about asymptomatic infection, accompanying community engagement must build trust in interventions through the active collaboration of government stakeholders, key local persons and community members. This entails training and devolving responsibilities to the community members to implement and sustain the control and elimination efforts.

Between 2013 and 2017, targeted malaria elimination (TME), a package of interventions that includes mass drug administration (MDA)-was piloted in communities with reservoirs of asymptomatic P. falciparum across the Greater Mekong sub-Region (GMS). Coverage in target communities is a key determinant of the effectiveness of MDA. Drawing on mixed methods research conducted alongside TME pilot studies, this article examines the impact of the community engagement, local social context and study design on MDA coverage. Qualitative and quantitative data were collected using questionnaire-based surveys, semi-structured and in-depth interviews, focus group discussions, informal conversations, and observations of study activities. Over 1500 respondents were interviewed in Myanmar, Vietnam, Cambodia and Laos. Interview topics included attitudes to malaria and experiences of MDA. Overall coverage of mass anti-malarial administration was high, particularly participation in at least a single round (85%). Familiarity with and concern about malaria prompted participation in MDA; as did awareness of MDA and familiarity with the aim of eliminating malaria. Fear of adverse events and blood draws discouraged people. Hence, community engagement activities sought to address these concerns but their impact was mediated by the trust relationships that study staff could engender in communities. In contexts of weak healthcare infrastructure and (cash) poverty, communities valued the study's ancillary care and the financial compensation. However, coverage did not necessarily decrease in the absence of cash compensation. Community dynamics, affected by politics, village conformity, and household decision-making also affected coverage. The experimental nature of TME presented particular challenges to achieving high coverage. Nonetheless, the findings reflect those from studies of MDA under implementation conditions and offer useful guidance for potential regional roll-out of MDA: it is key to understand target communities and provide appropriate information in tailored ways, using community engagement that engenders trust.

The increasing number and global distribution of pathogens resistant to antimicrobial drugs is potentially one of the greatest threats to global health, leading to health crises arising from infections that were once easy to treat. Infections resistant to antimicrobial treatment frequently result in longer hospital stays, higher medical costs, and increased mortality. Despite the long-standing recognition of antimicrobial resistance (AMR) across many settings, there is surprisingly poor information about its geographical distribution over time and trends in its population prevalence and incidence. This makes reliable assessments of the health burden attributable to AMR difficult, weakening the evidence base to drive forward research and policy agendas to combat AMR. The inclusion of mortality and morbidity data related to drug-resistant infections into the annual Global Burden of Disease Study should help fill this policy void.

The emergence and spread of resistance in Plasmodium falciparum malaria to artemisinin combination therapies in the Greater Mekong subregion poses a major threat to malaria control and elimination. The current study is part of a multi-country, open-label, randomised clinical trial (TRACII, 2015–18) evaluating the efficacy, safety, and tolerability of triple artemisinin combination therapies. A very high rate of treatment failure after treatment with dihydroartemisinin-piperaquine was observed in Thailand, Cambodia, and Vietnam. The immediate public health importance of our findings prompted us to report the efficacy data on dihydroartemisinin-piperaquine and its determinants ahead of the results of the overall trial, which will be published later this year. Patients aged between 2 and 65 years presenting with uncomplicated P falciparum or mixed species malaria at seven sites in Thailand, Cambodia, and Vietnam were randomly assigned to receive dihydroartemisinin-piperaquine with or without mefloquine, as part of the TRACII trial. The primary outcome was the PCR-corrected efficacy at day 42. Next-generation sequencing was used to assess the prevalence of molecular markers associated with artemisinin resistance (kelch13 mutations, in particular Cys580Tyr) and piperaquine resistance (plasmepsin-2 and plasmepsin-3 amplifications and crt mutations). This study is registered with ClinicalTrials.gov, number NCT02453308. Between Sept 28, 2015, and Jan 18, 2018, 539 patients with acute P falciparum malaria were screened for eligibility, 292 were enrolled, and 140 received dihydroartemisinin-piperaquine. The overall Kaplan-Meier estimate of PCR-corrected efficacy of dihydroartemisinin-piperaquine at day 42 was 50·0% (95% CI 41·1–58·3). PCR-corrected efficacies for individual sites were 12·7% (2·2–33·0) in northeastern Thailand, 38·2% (15·9–60·5) in western Cambodia, 73·4% (57·0–84·3) in Ratanakiri (northeastern Cambodia), and 47·1% (33·5–59·6) in Binh Phuoc (southwestern Vietnam). Treatment failure was associated independently with plasmepsin2/3 amplification status and four mutations in the crt gene (Thr93Ser, His97Tyr, Phe145Ile, and Ile218Phe). Compared with the results of our previous TRACI trial in 2011–13, the prevalence of molecular markers of artemisinin resistance (kelch13 Cys580Tyr mutations) and piperaquine resistance (plasmepsin2/3 amplifications and crt mutations) has increased substantially in the Greater Mekong subregion in the past decade. Dihydroartemisinin-piperaquine is not treating malaria effectively across the eastern Greater Mekong subregion. A highly drug-resistant P falciparum co-lineage is evolving, acquiring new resistance mechanisms, and spreading. Accelerated elimination of P falciparum malaria in this region is needed urgently, to prevent further spread and avoid a potential global health emergency. UK Department for International Development, Wellcome Trust, Bill & Melinda Gates Foundation, Medical Research Council, and National Institutes of Health.

Lung injury in preterm infants leads to structural and functional respiratory deficits, with a risk for bronchopulmonary dysplasia (BPD) that in its most severe form is accompanied by pulmonary hypertension (PH). To identify potential cellular and molecular drivers of BPD in humans, we performed single-cell RNA sequencing of preterm infant lungs with evolving BPD and BPD + PH compared to term infants. Examination of endothelial cells reveals a unique, aberrant capillary cell-state in BPD + PH defined by ANKRD1 expression. Within the alveolar parenchyma in infants with BPD/BPD + PH, predictive signaling analysis identifies surprising deficits in the semaphorin guidance-cue pathway, with decreased expression of pro-angiogenic transcription factor FOXF1 . Loss of semaphorin signaling is replicated in a murine BPD model and in humans with causal FOXF1 mutations for alveolar capillary dysplasia (ACDMPV), suggesting a mechanistic link between developmental programs underlying BPD and ACDMPV and uncovering a critical role for semaphorin signaling in normal lung development. How lung epithelial and endothelial cells develop into alveoli is a major knowledge gap, with implications for lung repair in preterm infants. Here, the authors establish a transcriptomic atlas of human neonatal lung disease, identifying semaphorins as pivotal mediators of organogenesis and injury.