Phylogenetics and environmental distribution of nitric oxide-forming nitrite reductases reveal their distinct functional and ecological roles.

The two evolutionarily unrelated nitric oxide-producing nitrite reductases, NirK and NirS, are best known for their redundant role in denitrification. They are also often found in organisms that do not perform denitrification. To assess the functional roles of the two enzymes and to address the sequence and structural variation within each, we reconstructed robust phylogenies of both proteins with sequences recovered from 6973 isolate and metagenome-assembled genomes and identified 32 well-supported clades of structurally distinct protein lineages. We then inferred the potential niche of each clade by considering other functional genes of the organisms carrying them as well as the relative abundances of each nir gene in 4082 environmental metagenomes across diverse aquatic, terrestrial, host-associated, and engineered biomes. We demonstrate that Nir phylogenies recapitulate ecology distinctly from the corresponding organismal phylogeny. While some clades of the nitrite reductase were equally prevalent across biomes, others had more restricted ranges. Nitrifiers make up a sizeable proportion of the nitrite-reducing community, especially for NirK in marine waters and dry soils. Furthermore, the two reductases showed distinct associations with genes involved in oxidizing and reducing other compounds, indicating that the NirS and NirK activities may be linked to different elemental cycles. Accordingly, the relative abundance and diversity of NirS versus NirK vary between biomes. Our results show the divergent ecological roles NirK and NirS-encoding organisms may play in the environment and provide a phylogenetic framework to distinguish the traits associated with organisms encoding the different lineages of nitrite reductases.

Impact of four years of annually repeated indoor residual spraying (IRS) with Actellic 300CS on routinely reported malaria cases in an agricultural setting in Malawi.

Indoor residual spraying (IRS) is one of the main vector control tools used in malaria prevention. This study evaluates IRS in the context of a privately run campaign conducted across a low-lying, irrigated, sugarcane estate from Illovo Sugar, in the Chikwawa district of Malawi. The effect of Actellic 300CS annual spraying over four years (2015-2018) was assessed using a negative binomial mixed effects model, in an area where pyrethroid resistance has previously been identified. With an unadjusted incidence rate ratio (IRR) of 0.38 (95% CI: 0.32-0.45) and an adjusted IRR of 0.50 (95% CI: 0.42-0.59), IRS has significantly contributed to a reduction in case incidence rates at Illovo, as compared to control clinics and time points outside of the six month protective period. This study shows how the consistency of a privately run IRS campaign can improve the health of employees. More research is needed on the duration of protection and optimal timing of IRS programmes.

A systematic review of circulating predictive and prognostic biomarkers to aid the personalised use of radiotherapy in the radical treatment of patients with oesophageal cancer.

BACKGROUND: The availability of circulating biomarkers that are predictive of treatment response or prognostic of overall outcome could enable the personalised and adaptive use of radiotherapy (RT) in patients with oesophageal adenocarcinoma (OAC) and squamous cell carcinoma (OSCC). METHODS: A systematic review was carried out following Preferred Reporting Items for Systematic Reviews guidance. Medline, EMBASE, PubMed, Cochrane Library, CINAHL, Scopus and the Web of Science databases were searched for studies published between January 2005-February 2023 relating to circulating biomarkers evaluated in the context of neoadjuvant or definitive RT delivered for OAC/OSCC. Study quality was assessed using predefined criteria. RESULTS: A total of 3012 studies were screened and 57 subsequently included, across which 61 biomarkers were reported. A majority (43/57,75.4%) of studies were of Asian origin and retrospective (40/57, 70.2%), with most (52/57, 91.2%) biomarkers reported in the context of patients with OSCC. There was marked inter-study heterogeneity in patient populations, treatment characteristics, biomarker measurement and the cut points used to define biomarker positivity. Nevertheless, there is evidence for the prognostic and predictive value of circulating tumour DNA and numerous miRNAs in OAC and OSCC, as well as for the prognostic and predictive value of circulating levels of CYFRA21.1 in OSCC. CONCLUSIONS: There is consistent evidence for the potential predictive and prognostic value of a small number of biomarkers in OSCC and OAC, though these data are insufficient for translation to current clinical practice. Well-designed prospective studies are now required to validate their role in stratified and personalised RT treatment approaches.

A perspective on the impacts of microplastics on mosquito biology and their vectorial capacity.

Microplastics (plastic particles <5 mm) permeate aquatic and terrestrial ecosystems and constitute a hazard to animal life. Although much research has been conducted on the effects of microplastics on marine and benthic organisms, less consideration has been given to insects, especially those adapted to urban environments. Here, we provide a perspective on the potential consequences of exposure to microplastics within typical larval habitat on mosquito biology. Mosquitoes represent an ideal organism in which to explore the biological effects of microplastics on terrestrial insects, not least because of their importance as an infectious disease vector. Drawing on evidence from other organisms and knowledge of the mosquito life cycle, we summarise some of the more plausible impacts of microplastics including physiological, ecotoxicological and immunological responses. We conclude that although there remains little experimental evidence demonstrating any adverse effect on mosquito biology or pathogen transmission, significant knowledge gaps remain, and there is now a need to quantify the effects that microplastic pollution could have on such an important disease vector.

Goal pursuit increases more after dietary success than after dietary failure: examining conflicting theories of self-regulation using ecological momentary assessment.

BACKGROUND: Maintaining a healthy body weight and reaching long-term dietary goals requires ongoing self-monitoring and behavioral adjustments. How individuals respond to successes and failures is described in models of self-regulation: while cybernetic models propose that failures lead to increased self-regulatory efforts and successes permit a reduction of such efforts, motivational models (e.g., social-cognitive theory) make opposite predictions. Here, we tested these conflicting models in an ecological momentary assessment (EMA) context and explored whether effort adjustments are related to inter-individual differences in perceived self-regulatory success in dieting (i.e., weight management). METHODS: Using linear mixed effects models, we tested in 174 diet-interested individuals whether current day dietary success or failure (e.g., on Monday) was followed by self-regulatory effort adjustment for the next day (e.g., on Tuesday) across 14 days. Success vs. failure was operationalized with two EMA items: first, whether food intake was higher vs. lower than usual and second, whether food intake was perceived as more vs. less goal-congruent than usual. Trait-level perceived self-regulatory success in dieting was measured on a questionnaire. RESULTS: Intended self-regulatory effort increased more strongly after days with dietary success (i.e., eating less than usual / rating intake as goal-congruent) than after days with dietary failure (i.e., eating more than usual / rating intake as goal-incongruent), especially in those individuals with lower scores on perceived self-regulatory success in dieting. CONCLUSIONS: Findings support mechanisms proposed by social-cognitive theory, especially in unsuccessful dieters. Thus, future dietary interventions could focus on preventing the decrease in self-regulatory effort after instances of dietary failures and thereby mitigate the potential risk that a single dietary failure initiates a downward spiral into unhealthy eating.

Multimodal Pain Management After Outpatient Orthopedic Hand Surgery: A Prospective Randomized Trial.

Purpose: Opioid stewardship ensures effective pain management while avoiding overprescribing of opioids after surgery. This prospective randomized study investigates the efficacy of a multimodal postoperative pain regimen compared to a traditional opioid-only pain regimen following elective outpatient orthopedic hand surgery. We hypothesized that patients receiving multimodal pain management would consume fewer opioids and report greater satisfaction than patients receiving only opioids. Methods: Consecutive patients undergoing outpatient hand and upper extremity surgery performed by two board-certified fellowship-trained orthopedic hand surgeons at one institution were recruited and randomized into either a study or control group. The study group received a standing multimodal postoperative regimen consisting of scheduled oral acetaminophen and naproxen as well as oxycodone to be taken as needed. The control group received only oxycodone to be taken as needed. Postoperatively, daily pain levels, medication usage, refills, satisfaction, and adverse events were recorded. Descriptive statistics were performed. Results: Of the 112 patients enrolled, 54 were randomized to the control group, and 58 were randomized to the study group. Study and control group patients did not differ significantly based on daily average pain scores or daily worst pain scores. However, study group patients reported fewer average daily oxycodone intake and total oxycodone pill count (7.0 vs 2.4 total pills, P <.005). In addition, the study group patients were more likely to report satisfaction with their postoperative pain control than control regimen patient's and were more likely to use the same pain regimen again if required. Conclusion: A multimodal postoperative pain regimen reduces opioid usage and has higher patient satisfaction rates in comparison to traditional opioid-only regimens. Use of multimodal pain regimens that use nonopioids, such as acetaminophen and naproxen, over an opioid should be considered for postoperative pain after orthopedic hand surgery. Level of Evidence: Therapeutic II.

Outcomes Following Fully Threaded Intramedullary Nailing of Metacarpal Fractures.

Purpose: Intramedullary screw fixation has emerged as a popular approach for the treatment of displaced metacarpal fractures. The purpose of this study was to investigate the functional and radiographic outcomes of a newly designed, headless noncompressive fully threaded intramedullary nail (TIMN) for the treatment of metacarpal fractures. Methods: A retrospective chart review was performed on patients who were treated with the INnate TIMN (ExsoMed) at a single academic institution with a minimum of 1-year follow-up. Patient-reported functional outcomes included Quick Disabilities for the Arm, Shoulder, and Hand (QuickDASH) questionnaires, return to work and physical activity time, and overall satisfaction. Radiographs were retrospectively reviewed to determine radiographic union, change in angulation, and metacarpal shortening. Results: A total of 49 patients (58 fractures) with a mean age of 36 years (range: 17-75 years) were included. The mean follow-up time was 2.7 years (range: 1.4-4.3 years). Overall, the mean patient satisfaction rating was 4.9 of 5 (range: 3-5). The mean return to work time was 7.2 weeks (range: 0.14-28 weeks), and the mean return to sport or activity was 8.3 weeks (range: 1-28 weeks). Average QuickDASH scores across all patients were 4 (range: 0-56.9). The median radiographic healing time was 6.1 weeks (range: 4.7-15.4 weeks). Mean postoperative shortening in the fifth metacarpal fracture was 3 mm (range: -4.2 to 8 mm) at the initial postoperative visit and 3.6 mm (range: -3.3 to 7.9 mm) at the final radiographic follow-up. Subgroup analysis showed that postoperative shortening was similar, regardless of the fracture pattern. The following four complications were reported: one case of persistent pain and stiffness, one case of carpal tunnel syndrome, one nonunion, and one fractured intramedullary nail. Conclusions: Our findings suggest that the TIMN allows for a reliable return to work and physical activity, high patient satisfaction, low complication rate, and minimal shortening at the final radiographic follow-up. Type of study/level of evidence: Therapeutic IV.

Posterior Interosseous Neuropathy Related to a Loose Distal Biceps Cortical Button: A Case Series.

Posterior interosseous nerve (PIN) injury is an uncommon yet debilitating complication following distal bicep tendon repair. There are case reports of acute intraoperative PIN injury related to retractor placement, drill trajectory, and nerve incarceration. We report three cases of delayed PIN neuropathy in the setting of a loose cortical button. All patients had resolution of their pain with removal of the cortical button and decompression of the radial tunnel. The purpose of this case series is to: 1) highlight the possibility of a loose cortical bicep button as the cause of proximal forearm pain and PIN neuropathy in the early or late postoperative timeframe; and 2) emphasize the importance of proper surgical technique and use of intraoperative fluoroscopy to assure the cortical button is well-fixed and flush with the radial shaft. .

Why we don't eat as intended: Moderators of the short-term intention-behaviour relation in food intake.

OBJECTIVES: A healthy diet is essential for preventing chronic disease and promoting overall health. Translating one's intention to eat healthy into actual behaviour has, however, proven difficult with a range of internal and contextual factors identified as driving eating behaviour. DESIGN: We leverage Temporal Self-Regulation Theory to examine these momentary determinants' direct and moderating effects on the intention-behaviour relation with Ecological Momentary Assessment (EMA). METHODS: Eighty-seven healthy participants (mage = 24.1 years; 59 women, 28 men) reported, 5 times daily for 10 weekdays, their intentions to stick to a self-set dietary restriction goal for the next 3 hr, the goal congruency of their eating behaviour in the past 3 hr, and a range of factors potentially influencing food intake, such as stress, emotions and environmental eating cues. RESULTS: Two-part multilevel modelling revealed that craving, availability of goal-incongruent foods, social eating cues, giving in to other temptations and weaker momentary intentions directly increased the risk and severity of goal-incongruent intake within the next 3 hr. Social cues, stress and craving further influence behaviour through altering intention implementation. CONCLUSIONS: Results imply that people regularly fail to implement intentions for 3-hr periods and that a range of factors influences this, both directly and by disrupting intentional processes. While for some barriers, fostering strong intentions throughout the day could be beneficial, others require different strategies for dietary adherence.

COVID Protection Behaviors, Mental Health, Risk Perceptions, and Control Beliefs: A Dynamic Temporal Network Analysis of Daily Diary Data.

BACKGROUND: To control infections, behavioral non-pharmaceutical interventions (NPIs) such as social distancing and hygiene measures (masking, hand hygiene) were implemented widely during the COVID-19 pandemic. At the same time, adherence to NPIs has also been implied in an increase in mental health problems. However, the designs of many existing studies are often poorly suited to disentangle complex relationships between NPI adherence, mental health symptoms, and health-related cognitions (risk perceptions, control beliefs). PURPOSE: To separate between- and temporal within-person associations between mental health, health-related cognitions, and NPI adherence. METHODS: Six-month ecological momentary assessment (EMA) study with six 4-day assessment bouts in 397 German adults. Daily measurement of adherence, mental health symptoms, and cognitions during bouts. We used dynamic temporal network analysis to estimate between-person, as well as contemporaneous and lagged within-person effects for distancing and hygiene NPIs. RESULTS: Distinct network clusters of mental health, health cognitions, and adherence emerged. Participants with higher control beliefs and higher susceptibility were also more adherent (between-person perspective). Within-person, similar findings emerged, additionally, distancing and loneliness were associated. Lagged findings suggest that better adherence to NPIs was associated with better mental health on subsequent days, whereas higher loneliness was associated with better subsequent hygiene adherence. CONCLUSIONS: Findings suggest no negative impact of NPI adherence on mental health or vice versa, but instead suggest that adherence might improve mental health symptoms. Control beliefs and risk perceptions are important covariates of adherence-both on between-person and within-person level.

Adhering to COVID protective behaviors might be less detrimental for mental health than some previous claims: Over 6 months in 2021­2022, adults from Germany who adhered to COVID protection recommendations (mask-wearing, hand hygiene, social distancing) on any one day reported better mental health the following days.

Curb the spread: Leveraging intensive longitudinal data to unravel within- and between-person processes in adherence to nonpharmaceutical interventions during COVID-19.

OBJECTIVES: Adhering to behavioral recommendations and nonpharmaceutical interventions (NPIs) is a key to control COVID-19 infection rates. However, rates have decreased globally, and potentially modifiable determinants of ongoing adherence and their interaction with social and physical momentary environments are still poorly understood. Here, we comprehensively examine within-person variations and between-person differences in known behavioral determinants (capability and motivation), as well as the moderating role of situational variable environmental factors (opportunity) in predicting adherence to hygiene and social distancing behaviors. METHOD: Ecological momentary assessment study over 6 months with monthly assessment bouts (4 days each and five daily assessments) in 623 German adults. Repeated daily assessments of capability, opportunity, motivation, and behavior (COM-B) model factors. Bayesian multilevel logistic regression models were estimated to examine main effects of COM-B factors and moderating effects of momentary environmental factors. RESULTS: Momentary adherence to NPIs was predicted by within-person changes in COM-B factors (motivation: intentions, goal conflict, and control beliefs; opportunities: regulations and norms). Between-person differences in capabilities (habit strength) and motivation (intentions and control beliefs) predicted adherence across situations. Situation-specific environmental factors moderated the motivation-behavior association (regulation measures increased; goal conflict and nonadherent others decreased the association). CONCLUSIONS: Individual momentary (within-person) and stable (between-person) motivation indicators predicted adherence. However, situational environmental factors such as regulations or norms have strong main effects and moderate the motivation-behavior translation. These findings have policy implications, supporting recent claims to not rely on the narrative of "personal responsibility," but instead combine health education measures to increase individual motivation with consistent regulation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Phyloecology of nitrate ammonifiers and their importance relative to denitrifiers in global terrestrial biomes.

Nitrate ammonification is important for soil nitrogen retention. However, the ecology of ammonifiers and their prevalence compared with denitrifiers, being competitors for nitrate, are overlooked. Here, we screen 1 million genomes for nrfA and onr, encoding ammonifier nitrite reductases. About 40% of ammonifier assemblies carry at least one denitrification gene and show higher potential for nitrous oxide production than consumption. We then use a phylogeny-based approach to recruit gene fragments of nrfA, onr and denitrification nitrite reductase genes (nirK, nirS) in 1861 global terrestrial metagenomes. nrfA outnumbers the nearly negligible onr counts in all biomes, but denitrification genes dominate, except in tundra. Random forest modelling teases apart the influence of the soil C/N on nrfA-ammonifier vs denitrifier abundance, showing an effect of nitrate rather than carbon content. This study demonstrates the multiple roles nitrate ammonifiers play in nitrogen cycling and identifies factors ultimately controlling the fate of soil nitrate.

Biomechanical Comparison of Fixation of Metacarpal Shaft Fractures With Intramedullary Threaded Nail and Dorsal Plate.

PURPOSE: The purpose of this study was to investigate the mechanical properties of metacarpal long oblique and transverse shaft fractures stabilized by threaded intramedullary nails and dorsal plates and screws. METHODS: Transverse and oblique midshaft osteotomies were created in 28 paired left and right metacarpal bones from four fresh frozen cadavers. Each matched pair was fixed with one 4.5-mm threaded intramedullary nail and one 2.0-mm dorsal stainless-steel plate and a screw construct. The bones were secured at the proximal end, by a 3-D-printed customized jig, to a tensile testing machine and were loaded through a Kevlar wire tensioned over the metacarpal head, simulating muscle/tendon loading during grip. Loading to failure was performed, and the applied force and failure mode were recorded. RESULTS: Oblique fractures fixed with nails failed at a greater force than those fixed with dorsal plates (183 ± 50 N vs 130 ± 40 N). Transverse fractures showed comparable strength between the nail (215 ± 33 N) and the plate (183 ± 64 N). Plate failure modes included three diverse types of bone fracture and yielding deformation of the plate. Intramedullary nail failure modes included yielding of the nail, bone fracture without nail yielding, and relative rotation between the two sections of the bone. CONCLUSIONS: Fixation of oblique and transverse metacarpal shaft fractures using a 4.5-mm threaded intramedullary nail in a simulated grip test model showed similar or greater strength than a 2.0-mm dorsal plate and screw construct. CLINICAL RELEVANCE: Threaded intramedullary nail fixation of metacarpal shaft fractures may be an appropriate alternative to plate fixation in these fracture patterns.

Radiographic Comparison of Forearm Symmetry in Healthy Individuals and its Importance in the Diagnosis of Longitudinal Radioulnar Dissociation.

PURPOSE: Longitudinal radioulnar dissociation (LRD) is an injury often missed upon initial presentation. A recent study examined a radiographic screening test in cadavers that showed increased interosseous distance when the interosseous ligament (IOL) was divided. For this test to be clinically useful, it is necessary for uninjured forearms to have similar interosseous spaces. The purpose of this study was to determine the typical differences between right and left interosseous spaces of healthy individuals. METHODS: Anterior-posterior x-rays of bilateral forearms in maximum supination of 28 surgical residents with no history of injury were obtained. These images were uploaded into a picture archiving and communication system and then digitized. The length of the radius was measured (Xr). The maximum interosseous distance (Dmax) between the radius and ulna as well as the interosseous distance at a location 0.3 Xr from the distal radioulnar joint was measured. The right and left arm distances were compared. Also, an outlier analysis was used to evaluate forearm rotational asymmetry between right and left arms. RESULTS: The outlier analysis revealed two sets of forearm x-rays were rotationally different compared to the rest of the group due to asymmetric arm positioning; these data were excluded from the analysis. The average difference in Dmax was 1.7 mm (standard deviation [SD] 1.5) between right and left arms, and this was found at a position of 0.28 Xr on average. The difference in interosseous distance measured at a fixed location 0.3 Xr was 1.6 mm (SD 1.5). No significant difference was found between the paired right and left arms for Dmax or at 0.3 Xr. CONCLUSIONS: There does not appear to be any significant difference between the maximum interosseous distance of right and left arms in healthy individuals. Therefore, analyzing bilateral forearm x-rays may be a simple LRD screening test. CLINICAL RELEVANCE: Understanding the degree of normal variation in the forearm bone spacing might inform evaluation of abnormal forearm bone alignment resulting from LRD.

Conformal 3D computed tomography planned endoluminal brachytherapy for the local control of esophageal cancer.

PURPOSE: To outline the toxicity, tolerability, and efficacy of a 3D conformal computed tomography planned endoluminal brachytherapy (ELBT) treatment for esophageal adenocarcinoma (OAC) or squamous cell carcinoma (OSCC). METHODS AND MATERIALS: A retrospective single-center analysis of toxicity, tolerability, and outcomes for 65 consecutive patients with OAC/OSCC who received 6-8Gy in one fraction or 12-16Gy in two fractions of high-dose-rate ELBT as salvage postchemoradiotherapy (n = 7 and n = 14 respectively), or as a boost to external beam radiotherapy (n = 14 and n = 30, respectively). RESULTS: Median overall survival from the first brachytherapy application was 7.4 (IQR 5.0-14.7) months for the boost cohort and 9.2 (IQR 5.8-20.1) months for the salvage cohort. In a univariate analysis, use of a higher, fractionated dose of radiotherapy was associated with longer overall survival. At least one-third (33%; n = 7) of the salvage cohort and 28% (n = 12) of the boost cohort exhibited a local recurrence prior to death. Overall, 66.7% of the salvage and 56.8% of the boost cohort experienced odynophagia. Swallow function stabilized or improved early after treatment, with only 11.6% of the boost and 14.3% of the salvage cohort demonstrating a long-term decline in dysphagia score. CONCLUSIONS: 3D conformal planned ELBT is safe and tolerable. Most patients exhibit an early and sustained stabilization or improvement in their swallow function and greater survival is seen with higher brachytherapy doses. Further research is required to determine the place of brachytherapy in the management of esophageal cancer, particularly when planned using contemporary conformal approaches.

Monitoring and simulating landscape changes: how do long-term changes in land use and long-term average climate affect regional biophysical conditions in southern Malawi?

We set out to reveal the effects of long-term changes in land use and long-term average climate on the regional biophysical environment in southern Malawi. Object-oriented supervised image classification was performed on Landsat 5 and 8 satellite images from 1990 to 2020 to identify and quantify past and present land use-land cover changes using a support vector machine classifier. Subsequently, using 2000 and 2010 land use-land cover in an artificial neural network, land use-land cover for 2020 driven by elevation, slope, precipitation and temperature, population density, poverty, distance to major roads, and distance to villages data was simulated. Between 1990 and 2020, area of land cover increased in built-up (209%), bare land (10%), and cropland (10%) and decreased in forest (30%), herbaceous (4%), shrubland (20%), and water area (20%). Overall, the findings reveal that southern Malawi is dominantly an agro-mosaic landscape shaped by the combined effects of urban and agricultural expansions and climate. The findings also suggest the need to enhance the machine learning algorithms to improve capacity for landscape modelling and, ultimately, prevention, preparedness, and response to environmental risks.

Integrating vector control within an emerging agricultural system in a region of climate vulnerability in southern Malawi: A focus on malaria, schistosomiasis, and arboviral diseases.

Infectious diseases are emerging at an unprecedented rate while food production intensifies to keep pace with population growth. Large-scale irrigation schemes have the potential to permanently transform the landscape with health, nutritional and socio-economic benefits; yet, this also leads to a shift in land-use patterns that can promote endemic and invasive insect vectors and pathogens. The balance between ensuring food security and preventing emerging infectious disease is a necessity; yet the impact of irrigation on vector-borne diseases at the epidemiological, entomological and economic level is uncertain and depends on the geographical and climatological context. Here, we highlight the risk factors and challenges facing vector-borne disease surveillance and control in an emerging agricultural ecosystem in the lower Shire Valley region of southern Malawi. A phased large scale irrigation programme (The Shire Valley Transformation Project, SVTP) promises to transform over 40,000 ha into viable and resilient farmland, yet the valley is endemic for malaria and schistosomiasis and experiences frequent extreme flooding events following tropical cyclones. The latter exacerbate vector-borne disease risk while simultaneously making any empirical assessment of that risk a significant hurdle. We propose that the SVTP provides a unique opportunity to take a One Health approach at mitigating vector-borne disease risk while maintaining agricultural output. A long-term and multi-disciplinary approach with buy-in from multiple stakeholders will be needed to achieve this goal.

Impact of Social Reference Cues on Misinformation Sharing on Social Media: Series of Experimental Studies.

BACKGROUND: Health-related misinformation on social media is a key challenge to effective and timely public health responses. Existing mitigation measures include flagging misinformation or providing links to correct information, but they have not yet targeted social processes. Current approaches focus on increasing scrutiny, providing corrections to misinformation (debunking), or alerting users prospectively about future misinformation (prebunking and inoculation). Here, we provide a test of a complementary strategy that focuses on the social processes inherent in social media use, in particular, social reinforcement, social identity, and injunctive norms. OBJECTIVE: This study aimed to examine whether providing balanced social reference cues (ie, cues that provide information on users sharing and, more importantly, not sharing specific content) in addition to flagging COVID-19-related misinformation leads to reductions in sharing behavior and improvement in overall sharing quality. METHODS: A total of 3 field experiments were conducted on Twitter's native social media feed (via a newly developed browser extension). Participants' feed was augmented to include misleading and control information, resulting in 4 groups: no-information control, Twitter's own misinformation warning (misinformation flag), social cue only, and combined misinformation flag and social cue. We tracked the content shared or liked by participants. Participants were provided with social information by referencing either their personal network on Twitter or all Twitter users. RESULTS: A total of 1424 Twitter users participated in 3 studies (n=824, n=322, and n=278). Across all 3 studies, we found that social cues that reference users' personal network combined with a misinformation flag reduced the sharing of misleading but not control information and improved overall sharing quality. We show that this improvement could be driven by a change in injunctive social norms (study 2) but not social identity (study 3). CONCLUSIONS: Social reference cues combined with misinformation flags can significantly and meaningfully reduce the amount of COVID-19-related misinformation shared and improve overall sharing quality. They are a feasible and scalable way to effectively curb the sharing of COVID-19-related misinformation on social media.

Comparative Bending Strength of Metacarpal Neck Fractures Fixed with Two Types of Intramedullary Screws.

Objectives: Intramedullary (IM) screw fixation of metacarpal fractures is a technique, which has gained in popularity owing to its simplicity, speedy rehabilitation, and good functional outcomes. A new, larger diameter, non-compression screw designed specifically for IM metacarpal fixation was recently introduced which could provide better fracture stability and reduce the risk of hardware failure. Our goal was to evaluate the strength of this screw compared to a first-generation screw. Methods: This mechanical study was designed to compare a 4.5 mm metacarpal headless screw (MCHS) to data from our prior research evaluating a 3.0 mm headless screw (HS). Accordingly, we used identical bone models, testing constructs, equipment, and protocols. A metacarpal neck osteotomy was created in 10 Sawbones models. A 4.5 mm x 50 mm MCHS was inserted retrograde to stabilize the fracture. Flexion bending strength was measured through a cable tension construct on a materials testing machine. Failure mechanism and strength was recorded and compared to data with a 3.0 mm screw construct. Results: Eight models failed by bending of the intramedullary screw. Two models failed by rotation of the metacarpal head. Failure occurred at an average of 539 N (Range 315 - 735 N). The MCHS demonstrated a significantly greater load to failure compared to the previously studied 3.0 mm HS at 215 N (P<0.05). Conclusion: A larger, 4.5 mm metacarpal-specific headless screw is more than twice as strong as a 3.0 mm diameter screw in a metacarpal neck fracture model.