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Industrial processes prominently feature π-acidic gases, and an adsorbent capable of selectively interacting with these molecules could enable important chemical separations 1 – 4 . Biological systems use accessible, reducing metal centres to bind and activate weakly π-acidic species, such as N 2 , through backbonding interactions 5 – 7 , and incorporating analogous moieties into a porous material should give rise to a similar adsorption mechanism for these gaseous substrates 8 . Here, we report a metal–organic framework featuring exposed vanadium( ii ) centres capable of back-donating electron density to weak π acids to successfully target π acidity for separation applications. This adsorption mechanism, together with a high concentration of available adsorption sites, results in record N 2 capacities and selectivities for the removal of N 2 from mixtures with CH 4 , while further enabling olefin/paraffin separations at elevated temperatures. Ultimately, incorporating such π-basic metal centres into porous materials offers a handle for capturing and activating key molecular species within next-generation adsorbents. Nitrogenases use transition metals to selectively capture weak π acids such as N 2 by employing backbonding interactions. Here, a metal–organic framework with exposed vanadium sites is presented that uses this approach for selective capture of N 2 from CH 4 , with impressive selectivity and capacity.

Soft X‐ray spectromicroscopy at the O K‐edge, U N4,5‐edges and Ce M4,5‐edges has been performed on focused ion beam sections of spent nuclear fuel for the first time, yielding chemical information on the sub‐micrometer scale. To analyze these data, a modification to non‐negative matrix factorization (NMF) was developed, in which the data are no longer required to be non‐negative, but the non‐negativity of the spectral components and fit coefficients is largely preserved. The modified NMF method was utilized at the O K‐edge to distinguish between two components, one present in the bulk of the sample similar to UO2 and one present at the interface of the sample which is a hyperstoichiometric UO2+x species. The species maps are consistent with a model of a thin layer of UO2+x over the entire sample, which is likely explained by oxidation after focused ion beam (FIB) sectioning. In addition to the uranium oxide bulk of the sample, Ce measurements were also performed to investigate the oxidation state of that fission product, which is the subject of considerable interest. Analysis of the Ce spectra shows that Ce is in a predominantly trivalent state, with a possible contribution from tetravalent Ce. Atom probe analysis was performed to provide confirmation of the presence and localization of Ce in the spent fuel. Soft X‐ray spectromicroscopy at the O K‐edge, U N4,5‐edges and Ce M4,5‐edges has been performed on focused ion beam sections of spent nuclear fuel for the first time. Analysis of oxygen spectra using a modified non‐negative matrix factorization method is consistent with a thin layer of hyperstoichiometric uranium oxide having been formed at the interface of a sample consisting of primarily UO2, probably formed after sample preparation. The cerium oxidation state is shown to be predominantly trivalent, with a possible small contribution from tetravalent Ce.

Industrial processes prominently feature π-acidic gases, and an adsorbent capable of selectively interacting with these molecules could enable important chemical separations. Biological systems use accessible, reducing metal centres to bind and activate weakly π-acidic species, such as N2, through backbonding interactions, and incorporating analogous moieties into a porous material should give rise to a similar adsorption mechanism for these gaseous substrates. In this work, we report a metal-organic framework featuring exposed vanadium(II) centres capable of back-donating electron density to weak π acids to successfully target π acidity for separation applications. This adsorption mechanism, together with a high concentration of available adsorption sites, results in record N2 capacities and selectivities for the removal of N2 from mixtures with CH4, while further enabling olefin/paraffin separations at elevated temperatures. Ultimately, incorporating such π-basic metal centres into porous materials offers a handle for capturing and activating key molecular species within next-generation adsorbents.

Background Hospitals use multiple concurrent prevention strategies to curb nosocomial C. difficile infection, but there are limited data on the long-term feasibility or safety of using a probiotic. Pierre-Le Gardeur Hospital, Québec, has been administering a probiotic comprised of Lactobacillus acidophilus CL1285, L. casei LBC80R and L. rhamnosus CLR2 since 2004 with documented results through March 31, 2014. Here we present an update for the past 5 years. Methods Several nosocomial infection prevention practices were running concurrently at the hospital. Adult inpatients treated with antibiotics from April 1, 2014 to March 31, 2019 were eligible to receive the probiotic. The hospital pharmacy ensured that each patient took the probiotic capsules (Bio-K+® 50 Billion) daily from the initiation of antibiotic use. Confirmed nosocomial cases of C. difficile infection were recorded and reported to the provincial public health agency. The rate of nosocomial CDI for this hospital was compared with other non-University affiliated hospitals in the health region with more than 110 beds and fewer than 45% of patients age 65 and older, and, to all other hospitals in the health system. Results Cumulatively over the past 15 years, more than sixty thousand antibiotic-treated adult inpatients took the probiotic daily during antibiotic use. Among 13 comparable hospitals, Pierre-Le Gardeur Hospital had the lowest rate of nosocomial CDI in 2014–2015, 2015–2016, 2016–2017, 2017–2018 and on average had the lowest rate for 2013–2018 (1.1 CDI cases per 10,000 patient-days). Compared with all hospitals in the Province of Quebec health system, N = 95, the hospital had the lowest nosocomial CDI rate on average for 2013–2018. No cases of Lactobacillus bacteremia were detected. Conclusion The overall infection prevention strategy has been highly effective, resulting in a consistently low rate of nosocomial CDI. We found that it is feasible to administer this probiotic to antibiotic-treated inpatients with few restrictions. No Lactobacillus infections were observed from any of the three strains of bacteria for this probiotic when given to more than sixty thousand adult inpatients. Disclosures All authors: No reported disclosures.

The purpose of this randomized, double-blind study was to evaluate the efficacy of midazolam and propofol for postoperative sedation and early extubation following cardiac surgery. ASA physical status II-III patients scheduled to undergo elective first-time cardiac surgery with an ejection fraction > 45% were eligible. All patients received a standardized sufentanil/isoflurane anaesthesia. During cardiopulmonary bypass 100 micrograms.kg-1.min-1 propofol was substituted for isoflurane. Upon arrival in the Intensive Care Unit (ICU), patients were randomized to either 10 micrograms.kg-1.min-1 propofol (n = 21) or 0.25 microgram.kg-1.min-1 midazolam (n = 20). Infusion rates were adjusted to maintain sedation within a predetermined range (Ramsay 2-4). The infusion was terminated after four hours. Patients were weaned from mechanical ventilation and their tracheas extubated when Haemodynamic stability, haemostasis, normothermia and mental orientation were confirmed. Haemodynamic measurements, arterial blood gas tensions and pulmonary function tests were recorded at specified times. There were no differences between the two groups for the time spent at each level of sedation, number of infusion rate adjustments, amount of analgesic and vasoactive drugs, times to awakening and extubation. The costs of propofol were higher than those of midazolam. There were no differences in haemodynamic values, arterial blood gas tensions and pulmonary function. We conclude that midazolam and propofol are safe and effective sedative agents permitting early extubation in this selected cardiac patient population but propofol costs were higher.

Health-related chatbots require safety assurance beyond factual correctness. We propose a red-teaming protocol for patient-facing AI structured around three pillars: error stratification, dual-pronged testing, and vulnerability-informed mitigation. We distinguish Document Adherence (DA) from Instruction Adherence (IA), deploying adversarial “attacks” across both single-turn and multi-turn exchanges to provoke system failures. We then applied layered mitigations informed by the vulnerabilities revealed by these attacks. We evaluate this framework on a retrieval-augmented generation (RAG) based chatbot designed to assist with health-related social needs (HRSN).The protocol identified behavioral noncompliance as the dominant risk. While robust in DA (0/60 errors), the system struggled with IA (15% error rate). Crucially, multi-turn stress tests revealed vulnerabilities hidden in single-turn checks: error rates spiked to 50% for advice queries and 40% for user distress. All high-severity failures occurred during these sustained interactions. Of our mitigations, prompt augmentation reduced total errors by 60%, while document augmentation mitigated single-turn distress errors. Combined, they eliminated high-severity errors entirely by forcing “safe failure” loops. We suggest this cycle of stratified analysis, depth-based testing, and targeted mitigation can be a guiding framework for securing clinical conversational agents.

Riboswitches are mRNA regulatory elements that control gene expression by altering their structure in response to specific metabolite binding. In bacteria, riboswitches consist of an aptamer that performs ligand recognition and an expression platform that regulates either transcription termination or translation initiation. Here, we describe a dual-acting riboswitch from Escherichia coli that, in addition to modulating translation initiation, also is directly involved in the control of initial mRNA decay. Upon lysine binding, the lysC riboswitch adopts a conformation that not only inhibits translation initiation but also exposes RNase E cleavage sites located in the riboswitch expression platform. However, in the absence of lysine, the riboswitch folds into an alternative conformation that simultaneously allows translation initiation and sequesters RNase E cleavage sites. Both regulatory activities can be individually inhibited, indicating that translation initiation and mRNA decay can be modulated independently using the same conformational switch. Because RNase E cleavage sites are located in the riboswitch sequence, this riboswitch provides a unique means for the riboswitch to modulate RNase E cleavage activity directly as a function of lysine. This dual inhibition is in contrast to other riboswitches, such as the thiamin pyrophosphate-sensing thiM riboswitch, which triggers mRNA decay only as a consequence of translation inhibition. The riboswitch control of RNase E cleavage activity is an example of a mechanism by which metabolite sensing is used to regulate gene expression of single genes or even large polycistronic mRNAs as a function of environmental changes.

Unmet health-related social needs (HRSNs) are major drivers of poor health outcomes in early childhood. Children with unmet HRSNs are at greater risk for developmental delays, caregiver stress, and increased healthcare utilization, yet current screening approaches in pediatric primary care are resource-intensive and inconsistently implemented. AI-powered chatbots (conversational agents or virtual assistants) may offer a private, secure, scalable, and cost-effective alternative for identifying unmet needs and connecting families to services. This protocol describes a pilot randomized controlled trial designed to evaluate the feasibility, acceptability, and usability of DAPHNE, an AI-driven chatbot developed to facilitate the identification of unmet HRSNs and provide personalized community resource referrals. One hundred caregivers of children under two years of age will be recruited from Nationwide Children’s Hospital pediatric primary care clinics and randomized to either the standard care (control) group or DAPHNE+ Standard care (intervention) group (n = 50 each arm). Caregivers will complete surveys at baseline, 1 month, 3 months, and 6 months post-intervention (depending on the measure). For the intervention group, participants will receive weekly chatbot prompts and on-demand access throughout the 6-month study period. Primary outcomes include study feasibility (recruitment, retention, and survey completion across both arms), acceptability (caregiver-reported ratings in both arms and intervention-specific ratings), and usability of the DAPHNE chatbot (System Usability Scale among intervention participants). Secondary outcomes includes caregiver-reported outcome measures (caregiver stress, self-efficacy, satisfaction with resource access, quality of life), and electronic health record-derived measures (including documentation of HRSN screening and referrals, adherence to well-child visits, missed appointments, emergency department utilization, and estimated healthcare costs). In addition, ten primary care providers will also participate to assess workflow integration and report on current HRSN practices. Mixed-methods analyses will integrate survey data, chatbot engagement metrics, and qualitative interviews to refine both the intervention and the study protocol. The results of this study will inform the design of a future multi-site trial to evaluate the efficacy and implementation of DAPHNE for addressing HRSNs in pediatric primary care. Trial registration: NCT07168382.

Head-to-tail cyclized bacteriocins are ribosomally synthesized antimicrobial peptides that are defined by peptide backbone cyclization involving the N- and C- terminal amino acids. Their cyclic nature and overall three-dimensional fold confer superior stability against extreme pH and temperature conditions, and protease degradation. Most of the characterized head-to-tail cyclized bacteriocins were discovered through a traditional approach that involved the screening of bacterial isolates for antimicrobial activity and subsequent isolation and characterization of the active molecule. In this study, we performed genome mining using transporter protein sequences associated with experimentally validated head-to-tail cyclized bacteriocins as driver sequences to search for novel bacteriocins. Biosynthetic gene cluster analysis was then performed to select the high probability functional gene clusters. A total of 387 producer strains that encode putative head-to-tail cyclized bacteriocins were identified. Sequence and phylogenetic analyses revealed that this class of bacteriocins is more diverse than previously thought. Furthermore, our genome mining strategy captured hits that were not identified in precursor-based bioprospecting, showcasing the utility of this approach to expanding the repertoire of head-to-tail cyclized bacteriocins. This work sets the stage for future isolation of novel head-to-tail cyclized bacteriocins to serve as possible alternatives to traditional antibiotics and potentially help address the increasing threat posed by resistant pathogens.

In this work stirred yogurts were produced using a technical scale pilot in which the cooling step was processed using either a tubular (THX; low shear) or a plate (PHX, high shear) heat exchanger. The aim was to determine how total solids (TS, adjusted using lactose) and fat contents (FC) impact stirred yogurt properties during storage, depending on the heat exchanger used. Using raw milk, cream, skim milk powder, and lactose, four yogurts were formulated at 16.5% TS and 4.2% proteins, with different FC (0.0, 1.3, 2.6, and 3.9%); one more control yogurt was formulated at 14% TS, 4.2% proteins, and 0.0% FC. Analyses of yogurts (firmness, viscosity, induced syneresis) were realized at days 1, 3, 7, 21, and 34 after production. The addition of lactose between the non-fat yogurt at 14 or 16.5% TS had little to no effect on stirred yogurt properties. Increasing FC reduced syneresis while increasing firmness and viscosity. The use of PHX reduced the syneresis compared to THX; however, it also tended to reduce the firmness of the yogurts with 3.9% FC.