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Ammonia (NH3) is a globally important commodity for fertilizer production, but its synthesis by the Haber-Bosch process causes substantial emissions of carbon dioxide. Alternative, zero-carbon emission NH3 synthesis methods being explored include the promising electrochemical lithium-mediated nitrogen reduction reaction, which has nonetheless required sacrificial sources of protons. In this study, a phosphonium salt is introduced as a proton shuttle to help resolve this limitation. The salt also provides additional ionic conductivity, enabling high NH3 production rates of 53 ± 1 nanomoles per second per square centimeter at 69 ± 1% faradaic efficiency in 20-hour experiments under 0.5-bar hydrogen and 19.5-bar nitrogen. Continuous operation for more than 3 days is demonstrated.Coherent optical excitations in two-dimensional (2D) materials, 2D polaritons, can generate a plethora of optical phenomena that arise from the extraordinary dispersion relations that do not exist in regular materials. Probing of the dynamical phenomena of 2D polaritons requires simultaneous spatial and temporal imaging capabilities and could reveal unknown coherent optical phenomena in 2D materials. Here, we present a spatiotemporal measurement of 2D wave packet dynamics, from its formation to its decay, using an ultrafast transmission electron microscope driven by femtosecond midinfrared pulses. The ability to coherently excite phonon-polariton wave packets and probe their evolution in a nondestructive manner reveals intriguing dispersion-dependent dynamics that includes splitting of multibranch wave packets and, unexpectedly, wave packet deceleration and acceleration. Having access to the full spatiotemporal dynamics of 2D wave packets can be used to illuminate puzzles in topological polaritons and discover exotic nonlinear optical phenomena in 2D materials.How eukaryotic cells assess and maintain sizes specific for their species and cell type remains unclear. We show that in the Arabidopsis shoot stem cell niche, cell size variability caused by asymmetric divisions is corrected by adjusting the growth period before DNA synthesis. KIP-related protein 4 (KRP4) inhibits progression to DNA synthesis and associates with mitotic chromosomes. The F BOX-LIKE 17 (FBL17) protein removes excess KRP4. Consequently, daughter cells are born with comparable amounts of KRP4. Inhibitor dilution models predicted that KRP4 inherited through chromatin would robustly regulate size, whereas inheritance of excess free KRP4 would disrupt size homeostasis, as confirmed by mutant analyses. We propose that a cell cycle regulator, stabilized by association with mitotic chromosomes, reads DNA content as a cell size-independent scale.Emergent resistance to all clinical antibiotics calls for the next generation of therapeutics. Here we report an effective antimicrobial strategy targeting the bacterial hydrogen sulfide (H2S)-mediated defense system. We identified cystathionine γ-lyase (CSE) as the primary generator of H2S in two major human pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, and discovered small molecules that inhibit bacterial CSE. These inhibitors potentiate bactericidal antibiotics against both pathogens in vitro and in mouse models of infection. CSE inhibitors also suppress bacterial tolerance, disrupting biofilm formation and substantially reducing the number of persister bacteria that survive antibiotic treatment. Our results establish bacterial H2S as a multifunctional defense factor and CSE as a drug target for versatile antibiotic enhancers.X-inactive specific transcript (Xist) RNA directs the process of X chromosome inactivation in mammals by spreading in cis along the chromosome from which it is transcribed and recruiting chromatin modifiers to silence gene transcription. To elucidate mechanisms of Xist RNA cis-confinement, we established a sequential dual-color labeling, super-resolution imaging approach to trace individual Xist RNA molecules over time, which enabled us to define fundamental parameters of spreading. We demonstrate a feedback mechanism linking Xist RNA synthesis and degradation and an unexpected physical coupling between preceding and newly synthesized Xist RNA molecules. Additionally, we find that the protein SPEN, a key factor for Xist-mediated gene silencing, has a distinct function in Xist RNA localization, stability, and coupling behaviors. Our results provide insights toward understanding the distinct dynamic properties of Xist RNA.Ecological resilience is the magnitude of the largest perturbation from which a system can still recover to its original state. However, a transition into another state may often be invoked by a series of minor synergistic perturbations rather than a single big one. We show how resilience can be estimated in terms of average life expectancy, accounting for this natural regime of variability. We use time series to fit a model that captures the stochastic as well as the deterministic components. The model is then used to estimate the mean exit time from the basin of attraction. ABBV-744 supplier This approach offers a fresh angle to anticipating the chance of a critical transition at a time when high-resolution time series are becoming increasingly available.Next-generation tissue-based biomarkers for immunotherapy will likely include the simultaneous analysis of multiple cell types and their spatial interactions, as well as distinct expression patterns of immunoregulatory molecules. Here, we introduce a comprehensive platform for multispectral imaging and mapping of multiple parameters in tumor tissue sections with high-fidelity single-cell resolution. Image analysis and data handling components were drawn from the field of astronomy. Using this "AstroPath" whole-slide platform and only six markers, we identified key features in pretreatment melanoma specimens that predicted response to anti-programmed cell death-1 (PD-1)-based therapy, including CD163+PD-L1- myeloid cells and CD8+FoxP3+PD-1low/mid T cells. These features were combined to stratify long-term survival after anti-PD-1 blockade. This signature was validated in an independent cohort of patients with melanoma from a different institution.A decade after the first report, the family of two-dimensional (2D) carbides and nitrides (MXenes) includes structures with three, five, seven, or nine layers of atoms in an ordered or solid solution form. Dozens of MXene compositions have been produced, resulting in MXenes with mixed surface terminations. MXenes have shown useful and tunable electronic, optical, mechanical, and electrochemical properties, leading to applications ranging from optoelectronics, electromagnetic interference shielding, and wireless antennas to energy storage, catalysis, sensing, and medicine. Here we present a forward-looking review of the field of MXenes. We discuss the challenges to be addressed and outline research directions that will deepen the fundamental understanding of the properties of MXenes and enable their hybridization with other 2D materials in various emerging technologies.Under-5 mortality rates in low and middle-income countries (LMIC) remain high. One major contributing factor is the failure to recognise critically unwell children when they first present to hospital. This leads to delayed or inadequate resuscitation and an increased risk of death.Triage is a key skill in this setting to sort the queue and prioritise patients, even when staff and equipment are scarce. In LMIC, children generally present late in their illness and often have progressed to some degree of multiorgan dysfunction.Following triage, a structured systematic primary survey is critical to ensure the detection of subtle signs of multiorgan dysfunction. Repeated physiological assessments of the child guide subsequent resuscitation management decisions, which depend somewhat on the resources available.It is possible to achieve significant improvements in survival of critically unwell children presenting for emergency care in the resource-limited setting. The three key steps in the patient's journey that we can influence in emergency care are triage, primary survey and initial stabilisation. Resources that address these steps have been developed for all settings. However, these resources were developed in a specific clinical context, and must therefore be adapted to local structures and processes. A systematic approach to triage and resuscitation saves lives.A 20-year-old man presented with recurrent subdural haemorrhages on a background of progressive sensorineural hearing loss, juvenile idiopathic arthritis and intracranial hypertension of unknown cause. His mother had a similar previous history. They both had a persistently mildly elevated serum C reactive protein. Repeat lumbar punctures identified persistently elevated intracranial pressure and mild pleocytosis. A dural biopsy showed necrotising pachymeningitis with granulomatous vasculitis. The underlying cause in both patients was a cryopyrin-associated periodic syndrome. We discuss its varied phenotype and how clinicians need to be aware of this treatable genetic condition to facilitate early treatment and to prevent accumulation of disability.

In fall 2020, community hubs opened in San Francisco, California, to support vulnerable groups of students in remote learning. Our objectives were to (1) describe adherence to coronavirus disease 2019 (COVID-19) mitigation policies in these urban, low-income educational settings; (2) assess associations between policy adherence and in-hub COVID-19 transmission; and (3) identify barriers to and facilitators of adherence.

We conducted a mixed-methods study from November 2020 to February 2021. We obtained COVID-19 case data from the San Francisco Department of Public Health, conducted field observations to observe adherence to COVID-19 mitigation policies, and surveyed hub leaders about barriers to and facilitators of adherence. We summarized quantitative data using descriptive statistics and qualitative data using thematic content analysis.

A total of 1738 children were enrolled in 85 hubs (39% Hispanic, 29% Black). We observed 54 hubs (

= 1175 observations of children and 295 observations of adults). Tential strategies for increasing adherence to COVID-19 mitigation.

Studies supporta recent decline in public benefit enrollment among immigrant families. We aimed to describe health and resource use, barriers to use, and immigration-related fear in families with undocumented parents compared with families without undocumented parents. We also aimed to assess associations with discontinuation of public benefits and fear of deportation.

We assessed immigration concerns and enrollment in Medicaid, Supplemental Nutrition Assistance Program (SNAP), and Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) with an 89-item anonymous, cross-sectional survey of English- and Spanish-speaking caregivers of hospitalized children. Multivariable logistic regression was used to assess associations with discontinuation of public benefits and fear of deportation.

Of 527 families approached, 399 enrolled (105 with 1 or more undocumented parent, 275 with no undocumented parent, and 19 with undisclosed immigration status). Compared with families without undocumented parents, families with undocumented parents had higher levels of poverty and food insecurity.