Ice front blocking of ocean heat transport to an Antarctic ice shelf.

Mass loss from the Antarctic Ice Sheet to the ocean has increased in recent decades, largely because the thinning of its floating ice shelves has allowed the outflow of grounded ice to accelerate1,2. Enhanced basal melting of the ice shelves is thought to be the ultimate driver of change2,3, motivating a recent focus on the processes that control ocean heat transport onto and across the seabed of the Antarctic continental shelf towards the ice4-6. However, the shoreward heat flux typically far exceeds that required to match observed melt rates2,7,8, suggesting that other critical controls exist. Here we show that the depth-independent (barotropic) component of the heat flow towards an ice shelf is blocked by the marked step shape of the ice front, and that only the depth-varying (baroclinic) component, which is typically much smaller, can enter the sub-ice cavity. Our results arise from direct observations of the Getz Ice Shelf system and laboratory experiments on a rotating platform. A similar blocking of the barotropic component may occur in other areas with comparable ice-bathymetry configurations, which may explain why changes in the density structure of the water column have been found to be a better indicator of basal melt rate variability than the heat transported onto the continental shelf9. Representing the step topography of the ice front accurately in models is thus important for simulating ocean heat fluxes and induced melt rates.

Publisher Correction: A weak topological insulator state in quasi-one-dimensional bismuth iodide.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

EMBL's European Bioinformatics Institute (EMBL-EBI) in 2023.

The European Molecular Biology Laboratory's European Bioinformatics Institute (EMBL-EBI) is one of the world's leading sources of public biomolecular data. Based at the Wellcome Genome Campus in Hinxton, UK, EMBL-EBI is one of six sites of the European Molecular Biology Laboratory (EMBL), Europe's only intergovernmental life sciences organisation. This overview summarises the latest developments in the services provided by EMBL-EBI data resources to scientific communities globally. These developments aim to ensure EMBL-EBI resources meet the current and future needs of these scientific communities, accelerating the impact of open biological data for all.

A weak topological insulator state in quasi-one-dimensional bismuth iodide.

The major breakthroughs in understanding of topological materials over the past decade were all triggered by the discovery of the Z2-type topological insulator-a type of material that is insulating in its interior but allows electron flow on its surface. In three dimensions, a topological insulator is classified as either 'strong' or 'weak'1,2, and experimental confirmations of the strong topological insulator rapidly followed theoretical predictions3-5. By contrast, the weak topological insulator (WTI) has so far eluded experimental verification, because the topological surface states emerge only on particular side surfaces, which are typically undetectable in real three-dimensional crystals6-10. Here we provide experimental evidence for the WTI state in a bismuth iodide, ß-Bi4I4. Notably, the crystal has naturally cleavable top and side planes-stacked via van der Waals forces-which have long been desirable for the experimental realization of the WTI state11,12. As a definitive signature of this state, we find a quasi-one-dimensional Dirac topological surface state at the side surface (the (100) plane), while the top surface (the (001) plane) is topologically dark with an absence of topological surface states. We also find that a crystal transition from the ß-phase to the α-phase drives a topological phase transition from a nontrivial WTI to a normal insulator at roughly room temperature. The weak topological phase-viewed as quantum spin Hall insulators stacked three-dimensionally13,14-will lay a foundation for technology that benefits from highly directional, dense spin currents that are protected against backscattering.

Nivolumab plus ipilimumab combination therapy in patients with advanced hepatocellular carcinoma previously treated with sorafenib: 5-year results from CheckMate 040.

BACKGROUND: Nivolumab plus ipilimumab demonstrated promising clinical activity and durable responses in sorafenib-treated patients with advanced hepatocellular carcinoma (HCC) in the CheckMate 040 study at 30.7-month median follow-up. Here, we present 5-year results from this cohort. PATIENTS AND METHODS: Patients were randomized 1 : 1 : 1 to arm A [nivolumab 1 mg/kg plus ipilimumab 3 mg/kg Q3W (four doses)] or arm B [nivolumab 3 mg/kg plus ipilimumab 1 mg/kg Q3W (four doses)], each followed by nivolumab 240 mg Q2W, or arm C (nivolumab 3 mg/kg Q2W plus ipilimumab 1 mg/kg Q6W). The primary objectives were safety, tolerability, investigator-assessed objective response rate (ORR), and duration of response (DOR) per RECIST version 1.1. RESULTS: A total of 148 patients were randomized across treatment arms. At 60-month minimum follow-up (62.6-month median follow-up), the ORR was 34% (n = 17), 27% (n = 13), and 29% (n = 14) in arms A, B, and C, respectively. The median DOR was 51.2 months [95% confidence interval (CI) 12.6 months-not estimable (NE)], 15.2 months (95% CI 7.1 months-NE), and 21.7 months (95% CI 4.2 months-NE), respectively. The median overall survival (OS) was 22.2 months (34/50; 95% CI 9.4-54.8 months) in arm A, 12.5 months (38/49; 95% CI 7.6-16.4 months) in arm B, and 12.7 months (40/49; 95% CI 7.4-30.5 months) in arm C; 60-month OS rates were 29%, 19%, and 21%, respectively. In an exploratory analysis of OS by response (6-month landmark), the median OS was meaningfully longer for responders versus nonresponders for all arms. No new safety signals were identified with longer follow-up. There were no new discontinuations due to immune-mediated adverse events since the primary analysis. CONCLUSIONS: Consistent with the primary analysis, the arm A regimen of nivolumab plus ipilimumab continued to demonstrate clinically meaningful responses and long-term survival benefit, with no new safety signals in patients with advanced HCC following sorafenib treatment, further supporting its use as a second-line treatment in these patients.

Nivolumab in sorafenib-naive and sorafenib-experienced patients with advanced hepatocellular carcinoma: 5-year follow-up from CheckMate 040.

BACKGROUND: Patients with advanced hepatocellular carcinoma (aHCC) have a poor prognosis and high mortality. Nivolumab monotherapy demonstrated clinical benefit with an acceptable safety profile in patients with aHCC in the CheckMate 040 study. Five-year follow-up of the sorafenib-naive and sorafenib-experienced groups of CheckMate 040 is presented here. PATIENTS AND METHODS: Patients received nivolumab monotherapy at dose levels of 0.1-10.0 mg/kg (dose-escalation phase) or 3 mg/kg (dose-expansion phase) every 2 weeks until disease progression or unacceptable toxicity. Primary endpoints were safety and tolerability (dose escalation), and objective response rate (ORR) by blinded independent central review (BICR) and by investigator as per RECIST version 1.1 (dose expansion). RESULTS: Eighty sorafenib-naive and 154 sorafenib-experienced patients were treated. Minimum follow-up in both groups was 60 months. ORR as per BICR was 20% [95% confidence interval (CI) 12% to 30%] and 14% (95% CI 9% to 21%) in the sorafenib-naive and sorafenib-experienced groups, respectively. Responses occurred regardless of HCC etiology or baseline tumor cell programmed death-ligand 1 (PD-L1) expression levels. Median overall survival (OS) was 26.6 months (95% CI 16.6-30.6 months) and 15.1 months (95% CI 13.0-18.2 months) in sorafenib-naive and sorafenib-experienced patients, respectively. The 3-year OS rates were 28% in the sorafenib-naive and 20% in the sorafenib-experienced groups; 5-year OS rates were 14% and 12%, respectively. No new safety signals were identified; grade 3/4 treatment-related adverse events were observed in 33% and 21% of patients in the sorafenib-naive and sorafenib-experienced groups, respectively. Biomarker analyses showed that baseline PD-L1 expression ≥1% was associated with higher ORR and longer OS compared with PD-L1 <1%. In the sorafenib-naive group, patients with OS ≥3 years exhibited higher baseline CD8 T-cell density compared with those with OS <1 year. CONCLUSION: With 5 years of follow-up, nivolumab monotherapy continued to provide durable clinical benefit with manageable safety in sorafenib-naive and sorafenib-experienced patients with aHCC.

Karrikin signalling: impacts on plant development and abiotic stress tolerance.

Plants rely upon a diverse range of metabolites to control growth and development, and to overcome stress that results from suboptimal conditions. Karrikins (KARs) are a class of butenolide compounds found in smoke that stimulate seed germination and regulate various developmental processes in plants. KARs are perceived via a plant α/ß-hydrolase called KARRIKIN INSENSITIVE2 (KAI2), which also functions as a receptor for a postulated phytohormone, provisionally termed KAI2 ligand (KL). Considered natural analogues of KL, KARs have been extensively studied for their effects on plant growth and their crosstalk with plant hormones. The perception and response pathway for KAR-KL signalling is closely related to that of strigolactones, another class of butenolides with numerous functions in regulating plant growth. KAR-KL signalling influences seed germination, seedling photomorphogenesis, root system architecture, abiotic stress responses, and arbuscular mycorrhizal symbiosis. Here, we summarize current knowledge of KAR-KL signalling, focusing on its role in plant development, its effects on stress tolerance, and its interaction with other signalling mechanisms.

Efficacy and acceptability of psychosocial interventions in schizophrenia: systematic overview and quality appraisal of the meta-analytic evidence.

Psychosocial interventions are recommended in schizophrenia and first-episode psychosis/early psychosis (EP). Nevertheless, literature is heterogeneous and often contradictory. We conducted an umbrella review of (network) meta-analyses of randomized controlled trials (RCTs) comparing psychosocial interventions vs treatment as usual (TAU)/active interventions(ACTIVE)/MIXED controls. Primary outcome was total symptoms (TS); secondary outcomes were positive/negative/depressive symptoms (PS/NS/DS), cognition, functioning, relapse, hospitalization, quality of life (QoL), treatment discontinuation. Standardized mean difference (SMD)/odds ratio (OR)/risk ratio (RR) vs TAU/ACTIVE/MIXED were summarized at end-of-treatment (EoT)/follow-up (FU). Quality was rated as high/medium/low (AMSTAR-PLUS). Eighty-three meta-analyses were included (RCTs = 1246; n = 84,925). Against TAU, regarding TS, Early Intervention Services (EIS) were superior EoT/FU in EP (SMD = -0.32/-0.21), cognitive behavioral therapy (CBT) in schizophrenia EoT/FU (SMD = -0.38/-0.19). Regarding secondary outcomes, in EP, EIS were superior for all outcomes EoT except cognition, and at FU for PS/NS/QoL, specific family interventions (FI-s) prevented relapse EoT; in schizophrenia, superiority emerged EoT for CBT for PS/NS/relapse/functioning/QoL; psychoeducation (EDU)/any FI for relapse; cognitive remediation therapy (CRT) for cognition/functioning; and hallucination-focused integrative treatment for PS. Against ACTIVE, in EP, mixed family interventions (FI-m) were superior at FU regarding TS (SMD = -0.61) and for functioning/relapse among secondary outcomes. In schizophrenia, regarding TS, mindfulness and social skills training (SST) were superior EoT, CBT at FU; regarding secondary outcomes superiority emerged at EoT for computerized cognitive drill-and-practice training for PS/DS, CRT for cognition/functioning, EDU for relapse, individual placement and support (IPS) for employment; and at FU CBT for PS/NS. Against MIXED, in schizophrenia, CRT/EDU were superior for TS EoT (d = -0.14/SMD = -0.33), CRT regarding secondary outcomes EoT for DS/social functioning, both EoT/FU for NS/cognition/global functioning; compensatory cognitive interventions for PS/functioning EoT/FU and NS EoT; CBT for PS at FU, and EDU/SST for relapse EoT. In conclusion, mental health services should consider prioritizing EIS/any FI in EP and CBT/CRT/any FI/IPS for schizophrenia, but other interventions may be helpful for specific outcomes.

Enhancing reinforcement learning models by including direct and indirect pathways improves performance on striatal dependent tasks.

A major advance in understanding learning behavior stems from experiments showing that reward learning requires dopamine inputs to striatal neurons and arises from synaptic plasticity of cortico-striatal synapses. Numerous reinforcement learning models mimic this dopamine-dependent synaptic plasticity by using the reward prediction error, which resembles dopamine neuron firing, to learn the best action in response to a set of cues. Though these models can explain many facets of behavior, reproducing some types of goal-directed behavior, such as renewal and reversal, require additional model components. Here we present a reinforcement learning model, TD2Q, which better corresponds to the basal ganglia with two Q matrices, one representing direct pathway neurons (G) and another representing indirect pathway neurons (N). Unlike previous two-Q architectures, a novel and critical aspect of TD2Q is to update the G and N matrices utilizing the temporal difference reward prediction error. A best action is selected for N and G using a softmax with a reward-dependent adaptive exploration parameter, and then differences are resolved using a second selection step applied to the two action probabilities. The model is tested on a range of multi-step tasks including extinction, renewal, discrimination; switching reward probability learning; and sequence learning. Simulations show that TD2Q produces behaviors similar to rodents in choice and sequence learning tasks, and that use of the temporal difference reward prediction error is required to learn multi-step tasks. Blocking the update rule on the N matrix blocks discrimination learning, as observed experimentally. Performance in the sequence learning task is dramatically improved with two matrices. These results suggest that including additional aspects of basal ganglia physiology can improve the performance of reinforcement learning models, better reproduce animal behaviors, and provide insight as to the role of direct- and indirect-pathway striatal neurons.

Clearance and nutrition in neonatal continuous kidney replacement therapy using the Carpediem™ system.

BACKGROUND: Infants with kidney failure (KF) demonstrate poor growth partly due to obligate fluid and protein restrictions. Delivery of liberalized nutrition on continuous kidney replacement therapy (CKRT) is impacted by clinical instability, technical dialysis challenges, solute clearance, and nitrogen balance. We analyzed delivered nutrition and growth in infants receiving CKRT with the Cardio-Renal, Pediatric Dialysis Emergency Machine (Carpediem™). METHODS: Single-center observational study of infants receiving CKRT with the Carpediem™ between June 1 and December 31, 2021. We collected prospective circuit characteristics, delivered nutrition, anthropometric measurements, and illness severity Score for Neonatal Acute Physiology-II. As a surrogate to normalized protein catabolic rate in maintenance hemodialysis, we calculated normalized protein nitrogen appearance (nPNA) using the Randerson II continuous dialysis model. Descriptive statistics, Spearman correlation coefficient, Mann Whitney, Wilcoxon signed rank, receiver operating characteristic curves, and Kruskal-Wallis analysis were performed using SAS version 9.4. RESULTS: Eight infants received 31.9 (22.0, 49.7) days of CKRT using mostly (90%) regional citrate anticoagulation. Delivered nutritional volume, protein, total calories, enteral calories, nPNA, and nitrogen balance increased on CKRT. Using parenteral nutrition, 90 ml/kg/day should meet caloric and protein needs. Following initial weight loss of likely fluid overload, exploratory sensitivity analysis suggests weight gain occurred after 14 days of CKRT. Despite adequate nutritional delivery, goal weight (z-score = 0) and growth velocity were not achieved until 6 months after CKRT start. Most (5 infants, 62.5%) survived and transitioned to peritoneal dialysis (PD). CONCLUSIONS: Carpediem™ is a safe and efficacious bridge to PD in neonatal KF. Growth velocity of infants on CKRT appears delayed despite delivery of adequate calories and protein.

Evaluation of Zn-Cd-Sn-S nanostructures for in vitro pyrene degradation and antimicrobial activity.

The present work describes the fabrication of the quaternary Zn-Cd-Sn-S nanostructure and its use in photocatalytic remediation of the biological contaminant pyrene from water resources. Nanostructures fabricated were characterized by XRD, UV-DRS, FTIR, DLS, EDX, and SEM. In addition, an agar well diffusion test was conducted to determine the antimicrobial activity. Zn-Cd-Sn-S (ZCSS) nanostructures were evaluated for their photocatalytic degrading potential by using pyrene as a model pollutant and evaluating the effects of parameters like initial pyrene concentration, nanocatalyst dosage, solution pH, and light sources during batch adsorption. Nanostructures had a size of 16.74 nm according to the XRD analysis. With a 300 min time interval, ZCSS nanostructures achieved the highest removal rate of 86.3%. Pyrene degradation metabolites were identified using GC-MS analysis of the degraded samples. A Freundlich isothermal (R2 0.9) and pseudo-first-order (R2 0.952) reaction kinetic path best fit the adsorption results for pyrene by the fabricated ZCSS nanostructure, based on the adsorption and kinetic studies. Zn-Cd-Sn-S exhibited the highest antibacterial activity against Staphylococcusaureus (22.4 mM). Due to the combined synergistic actions of the constituent metals, this quaternary nanostructure exhibited exceptional photocatalytic activity. To our est knowledge, the ZCSS nanostructure was made and used to remove pyrene by photocatalysis and fight microbes. Ultimately, the ZCSS nanostructure was found to be an effective photocatalyst for eradicating pathogenic microbes from water.

Enhanced photocatalytic degradation of polycyclic aromatic hydrocarbons (PAHs) Using NiO nanoparticles.

The oncogenic and genetic properties of anthracene, a member of the polycyclic aromatic hydrocarbons (PAHs) family, pose a significant health threat to humans. This study aims to investigate the photocatalytic decomposition of anthracene under various conditions, such as different concentrations of PAHs, varying amounts of NiO (nickel oxide) nanoparticles, and different pH levels under ultraviolet light and sunlight. The synthesized NiO nanoparticles showed surface plasma resonance at 230 and 360 nm, while XRD and SEM analysis confirmed the nanoparticles were cubic crystalline in structure with sizes ranging between 37 and 126 nm. NiO nanoparticles exhibited 79% degradation of pyrene at 2 µg/mL of anthracene within 60 min of treatment. NiO at 10 µg/mL concentration showed significant adsorption of 57%, while the adsorption method worked efficiently (72%) at 5 pH. Photocatalytic degradation was confirmed by isotherm and kinetic studies through monolayer adsorption and pseudo-first-order kinetics. Further, the absorption process was confirmed by performing GC-MS analysis of the NiO nanoparticles. On the other hand, NiO nanoparticles showed antimicrobial activity against Gram negative and Gram-positive bacteria. Therefore, the present work is one of its kind proving the dual application of NiO nanoparticles, which makes them suitable candidates for bioremediation by treating PAHs and killing pathogenic bacteria.

Factor structure of posttraumatic stress disorder (PTSD) in persons with serious mental illness.

BACKGROUND: Trauma and posttraumatic stress disorder (PTSD) are common among individuals with serious mental illness (SMI; e.g., schizophrenia, schizoaffective disorder, bipolar disorder, treatment refractory major depressive disorder), with resultant functional impairment. Previous studies have not evaluated the factor structure of the PTSD Checklist (PCL) among persons with SMI. AIMS: This study evaluated the factor structure of the PCL in two large SMI samples from public mental health treatment sectors screened for PTSD using the PCL. METHODS: Four different models of PTSD were tested using confirmatory factor analyses. RESULTS: Results indicated that the DSM-5 4-factor model (intrusion, avoidance, numbing, and hyperarousal) had the best fit. Further, the DSM-5 4-factor model demonstrated measurement invariance. CONCLUSIONS: Results supported the suitability of the DSM-5 4-factor model of PTSD among people with SMI.

Flat Γ Moiré Bands in Twisted Bilayer WSe_{2}.

The recent observation of correlated phases in transition metal dichalcogenide moiré systems at integer and fractional filling promises new insight into metal-insulator transitions and the unusual states of matter that can emerge near such transitions. Here, we combine real- and momentum-space mapping techniques to study moiré superlattice effects in 57.4° twisted WSe_{2} (tWSe_{2}). Our data reveal a split-off flat band that derives from the monolayer Γ states. Using advanced data analysis, we directly quantify the moiré potential from our data. We further demonstrate that the global valence band maximum in tWSe_{2} is close in energy to this flat band but derives from the monolayer K states which show weaker superlattice effects. These results constrain theoretical models and open the perspective that Γ-valley flat bands might be involved in the correlated physics of twisted WSe_{2}.

Fate of Quasiparticles at High Temperature in the Correlated Metal Sr_{2}RuO_{4}.

We study the temperature evolution of quasiparticles in the correlated metal Sr_{2}RuO_{4}. Our angle resolved photoemission data show that quasiparticles persist up to temperatures above 200 K, far beyond the Fermi liquid regime. Extracting the quasiparticle self-energy, we demonstrate that the quasiparticle residue Z increases with increasing temperature. Quasiparticles eventually disappear on approaching the bad metal state of Sr_{2}RuO_{4} not by losing weight but via excessive broadening from super-Planckian scattering. We further show that the Fermi surface of Sr_{2}RuO_{4}-defined as the loci where the spectral function peaks-deflates with increasing temperature. These findings are in semiquantitative agreement with dynamical mean field theory calculations.

Relapse prevention through health technology program reduces hospitalization in schizophrenia.

BACKGROUND: Psychiatric hospitalization is a major driver of cost in the treatment of schizophrenia. Here, we asked whether a technology-enhanced approach to relapse prevention could reduce days spent in a hospital after discharge. METHODS: The Improving Care and Reducing Cost (ICRC) study was a quasi-experimental clinical trial in outpatients with schizophrenia conducted between 26 February 2013 and 17 April 2015 at 10 different sites in the USA in an outpatient setting. Patients were between 18 and 60 years old with a diagnosis of schizophrenia, schizoaffective disorder, or psychotic disorder not otherwise specified. Patients received usual care or a technology-enhanced relapse prevention program during a 6-month period after discharge. The health technology program included in-person, individualized relapse prevention planning with treatments delivered via smartphones and computers, as well as a web-based prescriber decision support program. The main outcome measure was days spent in a psychiatric hospital during 6 months after discharge. RESULTS: The study included 462 patients, of which 438 had complete baseline data and were thus used for propensity matching and analysis. Control participants (N = 89; 37 females) were enrolled first and received usual care for relapse prevention followed by 349 participants (128 females) who received technology-enhanced relapse prevention. During 6-month follow-up, 43% of control and 24% of intervention participants were hospitalized (χ2 = 11.76, p<0.001). Days of hospitalization were reduced by 5 days (mean days: b = -4.58, 95% CI -9.03 to -0.13, p = 0.044) in the intervention condition compared to control. CONCLUSIONS: These results suggest that technology-enhanced relapse prevention is an effective and feasible way to reduce rehospitalization days among patients with schizophrenia.

Physical Function Assessment of Older Veterans With Serious Mental Illness.

OBJECTIVE: To characterize the physical function of older veterans with serious mental illness (SMI) across endurance, strength, and mobility domains. DESIGN: Retrospective analysis of clinical performance data. SETTING: Gerofit program, a national outpatient supervised exercise program for older veterans, delivered in Veterans Health Administration sites. PARTICIPANTS: Older veterans aged 60 and older (n = 166 with SMI, n = 1,441 without SMI) enrolled across eight national Gerofit sites between 2010 and 2019. MEASUREMENTS: Performance measures of physical function covering endurance (6-minute walk test), strength (chair stands, arm curls), and mobility (10-m walk, 8-foot-up-and-go), were administered at Gerofit enrollment. Baseline data from these measures were analyzed to characterize the functional profiles of older veterans with SMI. One sample t tests were examined to compare functional performance of older veterans with SMI to age- and sex-based reference scores. Propensity score matching (1:3) and linear mixed effects models were used to evaluate differences in function between veterans with and without SMI. RESULTS: Older veterans with SMI performed worse on all measures of function (chair stands, arm curls, 10-m walk, 6-minute walk test, 8-foot-up-and-go) compared to age- and sex-based reference scores with statistically significant differences present in the male sample. Functional performance of those with SMI was also worse compared to propensity-score matched older veterans without SMI with statistically significant differences on chair stands, 6-minute walk test, and 10-m walk. CONCLUSION: Older veterans with SMI have compromised strength, mobility, and endurance. Physical function should be a core component of screening and treatment for this population.

Convergent Total Synthesis of Exochelin 772SM.

A convergent total synthesis of the natural mycobacterial iron chelator desferri-exochelin 772SM (D-EXO) is described. The synthetic procedure proceeds in 11 steps in the longest linear sequence, with an overall yield of 8.6%. The described procedure uses cheap starting materials and requires a limited number of chromatographic purifications. The concise strategy divides the exochelin into five key building blocks, allowing easy alternation of each single building block. Herein, the presented synthetic strategy is well suited to facilitate the synthesis of analogues and medicinal chemistry development efforts in a time- and resource-efficient manner.

A collagen-based layered chronic wound biofilm model for testing antimicrobial wound products.

A new in vitro chronic wound biofilm model was recently published, which provided a layered scaffold simulating mammalian tissue composition on which topical wound care products could be tested. In this paper, we updated the model even further to mimic the dynamic influx of nutrients from below as is the case in a chronic wound. The modified in vitro model was created using collagen instead of agar as the main matrix component and contained both Staphylococcus aureus and Pseudomonas aeruginosa. The model was cast in transwell inserts and then placed in wound simulating media, which allowed for an exchange of nutrients and waste products across a filter. Three potential wound care products and chlorhexidine digluconate 2% solution as a positive control were used to evaluate the model. The tested products were composed of hydrogels made from completely biodegradable starch microspheres carrying different active compounds. The compounds were applied topically and left for 2-4 days. Profiles of oxygen concentration and pH were measured to assess the effect of treatments on bacterial activity. Confocal microscope images were obtained of the models to visualise the existence of microcolonies. Results showed that the modified in vitro model maintained a stable number of the two bacterial species over 6 days. In untreated models, steep oxygen gradients developed and pH increased to >8.0. Hydrogels containing active compounds alleviated the high oxygen consumption and decreased pH drastically. Moreover, all three hydrogels reduced the colony forming units significantly and to a larger extent than the chlorhexidine control treatment. Overall, the modified model expressed several characteristics similar to in vivo chronic wounds.

Cannabis use frequency and pain interference among people with HIV.

Cannabis is often used by people with HIV (PWH) for pain, yet study results are inconsistent regarding whether and how it affects pain. This study examines whether greater cannabis use frequency is associated with lower pain interference and whether cannabis use modifies the association of pain severity and pain interference among 134 PWH with substance dependence or a lifetime history of injection drug use. Multi-variable linear regression models examined the association between past 30-day cannabis use frequency and pain interference. Additional models evaluated whether cannabis use modified the association between pain severity and pain interference. Cannabis use frequency was not significantly associated with pain interference. However, in a model with interaction between cannabis use frequency and pain severity, greater cannabis use frequency attenuated the strength of the association between pain severity and pain interference (p = 0.049). The adjusted mean difference (AMD) in pain interference was +1.13, + 0.81, and +0.05 points for each 1-point increase in pain severity for those with no cannabis use, 15 days of use, and daily use, respectively. These findings suggest that attenuating the impact of pain severity on pain-related functional impairment is a potential mechanism for a beneficial role of cannabis for PWH.