We report the results of density-functional theory calculations for the dissociative adsorption of methane (DAM) on CaO(001) doped with Li, Na, K, and Cu. The presence of these dopants lowers the energy of oxygen-vacancy formation, increases the energy of the DAM reaction, and lowers the activation energy for DAM. We performed the same calculations for a stepped CaO(001) surface doped with Na and found that Na prefers being located at a step and the activation energy for DAM is lower at this step than on the doped, flat surface. We propose that such trends are valid for all oxides doped with lower-valence dopants. © 2013 American Chemical Society.

We use density functional theory to examine the dissociative adsorption of ethane on the surface of Nb-doped NiO. We find that the Nb dopant that substitutes a Ni atom in the surface layer of NiO adsorbs O2 from gas phase and binds it so strongly that the two oxygen atoms are no longer good oxidants. It is more reasonable to consider that the dopant is the NbO 2 group. We show that this group acts in many ways like a lower-valence dopant and activates the surface oxygen atoms near it. © 2013 American Chemical Society.

Background

Gastrointestinal pathogen panels (GPPs) are increasingly used to identify stool pathogens, but their impact in people with HIV (PWH) is unknown. We performed a retrospective cohort study comparing GPP and conventional stool evaluation in PWH.

Methods

We included all PWH who underwent GPP (Biofire Diagnostics; implemented September 15, 2015) or conventional testing, including stool culture, Clostridium difficile polymerase chain reaction testing, fluorescent smears for Cryptosporidium or Giardia, and ova and parasite exams (O&P) from 2013 to 2017. A total of 1941 specimens were tested, with 169 positive specimens detected in 144 patients. We compared result turnaround time, pathogen co-infection, antibiotic treatment, and treatment outcomes between positive specimens detected by conventional testing vs GPP.

Results

Overall, 124 patient samples tested positive by GPP, compared with 45 patient specimens by conventional testing. The GPP group demonstrated a higher co-infection rate (48.4% vs 13.3%; P < .001) and quicker turnaround time (23.4 vs 71.4 hours; P < .001). The GPP identified 29 potential viral infections that were undetectable by conventional stool tests. Unnecessary anti-infective therapy was avoided in 9 of 11 exclusively viral infections. Exclusively nonpathogenic parasites (n = 13) were detected by conventional stool tests, the majority of which were treated with metronidazole. There were no significant differences in clinical outcomes between groups.

Conclusions

In PWH, GPP implementation improved antibiotic stewardship through shorter turnaround times and detection of enteric viral pathogens.

Latently infected CD4 lymphocytes preclude cure of HIV infection, even with the most effective antiretroviral therapy. The replication competent latent HIV reservoir has been quantified with the terminal dilution quantitative viral outgrowth assay, which induces virus propagation in CD4⁺ T cell culture supernatants following cellular activation. Efforts to improve the sensitivity of this inefficient assay have introduced more sensitive p24 ELISA and RNA PCR based endpoints, but these more sensitive endpoints have raised the question whether they are measuring induced replication competent or defective virions. Here we performed parallel terminal dilution assays with CD4 lymphocytes from subjects effectively treated with antiretroviral therapy. An HIV integrase inhibitor was incorporated into one set of parallel cultures to compare the frequency of cells that can be induced to produce virions to those that produce virus that can propagate and amplify with co-culture in permissive cells. The majority of cells that can be induced to generate virus particles are producing replication competent virus, thus justifying more sensitive and faster assays of this reservoir.

Abstract

Evaluate the impact of switching to an anti-retroviral regimen containing tenofovir alafenamide (TAF) on weight and the development of metabolic complications compared to remaining on a non-TAF containing regimen.Single-center retrospective case-control study.We evaluated people living with human immunodeficiency virus (PLWH) who were on an anti-retroviral regimen not containing TAF and were switched to a regimen containing TAF between January 1, 2016 and September 30, 2018. The control group included PLWH on a TAF free regimen throughout the study period. The primary outcome was change in weight from baseline to 12 months postswitch. Secondary outcomes included percent change in weight, change in body mass index (BMI), change in BMI class, and new diagnoses of diabetes, hypertension, and hyperlipidemia (HLD) during the study period.PLWH switched to TAF (n = 446) demonstrated significantly greater mean increase in weight compared to the control group (n = 162) (1.97 vs 0.88 kg, P = .01), however the effect was only seen in those switched from tenofovir disoproxil fumarate. Those that switched to TAF also had a significantly higher percent increase in weight, increase in BMI, and BMI class. We observed a higher rate of new diagnosis of HLD in the control group compared to the TAF switch group during the study period.PLWH switched to TAF had greater increases in weight after 1 year as compared to those continuing on a TAF free regimen. However, this did not translate to higher rates of obesity related illnesses such as diabetes, hypertension, and HLD during the follow up period.

Summary HIV transmission risk is increased during antiretroviral therapy (ART) use if individuals are not virologically suppressed and engage in high risk transmission behaviour. Baseline data of HIV-infected men who have sex with men (MSM) with recent history of risky behaviour on ART for ≥3 months (n = 139) were evaluated to assess predictors of detectable viraemia and HIV transmission risk-taking behaviour. Twenty-four subjects had viral load (VL) >75 copies/mL and 12 had VL >1000 copies/mL. In multivariable regression analyses, subjects with VL >75 copies/mL were more likely to be Black (OR = 4.48, p = 0.007), have lower CD4 cell counts (OR = 0.727, p = 0.005) and have used methamphetamines in the last month (OR = 6.64, p = 0.019). Subjects with VL >1000 copies/mL were more likely to have lower CD4 cell counts (OR = 0.494, p = 0.004), report <90% adherence (OR = 7.94; p = 0.046) and have used methamphetamines in the last month (OR = 10.01, p = 0.034). Subjects with VL >75 copies/mL with the greatest transmission risk behaviour (n = 14) were more likely to be Black (OR = 8.00, p = 0.006), have lower CD4 cell counts (OR = 0.657, p = 0.009) and have used methamphetamines in the last month (OR = 5.20, p = 0.042). High risk HIV transmission behaviour with viraemia occurred in 10% of the cohort. Future efforts to reduce HIV transmission among MSM on ART will require combined interventions that target risk-taking behaviours and substance use.

Background

Given the prevalence and harms of incarceration among persons who inject drugs (PWID) and their role in injection drug use initiation, we aimed to investigate whether recent incarceration influences the likelihood PWID assist others in their first-ever injection.

Methods

Prospective cohort study of PWID in Vancouver, Canada who had their PReventing Injecting by Modifying Existing Responses (PRIMER) baseline visit between December 2014 and May 2017, reported never providing injection initiation assistance previously, and had ≥1 follow-up visit. The primary outcome, provision of injection initiation assistance, was defined via self-report as helping anybody inject for the first time in the past six months. The primary exposure was recent incarceration, i.e., self-report of being jailed, imprisoned or detained in the past six months. Participants were assessed biannually until November 2017, drop-out, or their first report of the primary outcome.

Results

1,199 PWID (62.1% male; mean (SD) age, 44.4 (12.3) years) were included in our study. Across 4,171 follow-up visits, 67 participants (5.6%) reported providing injection initiation assistance. The proportion of participants reporting recent incarceration varied between 2.4% to 5.1% per follow-up visit. Based on a multivariable discrete-time proportional hazards regression analysis, recent incarceration was associated with an increased risk of providing injection initiation assistance during the same six-month period (adjusted hazard ratio, 2.64; 95% CI, 1.19 to 5.86).

Conclusions

The observed association between recent incarceration and risk of providing injection initiation assistance suggests that incarceration could be contributing to the expansion of injection drug use practices within vulnerable populations over time.

Background

Gastrointestinal pathogen panels (GPPs) are increasingly used to identify stool pathogens, but their impact in people with HIV (PWH) is unknown. We performed a retrospective cohort study comparing GPP and conventional stool evaluation in PWH.

Methods

We included all PWH who underwent GPP (Biofire Diagnostics; implemented September 15, 2015) or conventional testing, including stool culture, Clostridium difficile polymerase chain reaction testing, fluorescent smears for Cryptosporidium or Giardia, and ova and parasite exams (O&P) from 2013 to 2017. A total of 1941 specimens were tested, with 169 positive specimens detected in 144 patients. We compared result turnaround time, pathogen co-infection, antibiotic treatment, and treatment outcomes between positive specimens detected by conventional testing vs GPP.

Results

Overall, 124 patient samples tested positive by GPP, compared with 45 patient specimens by conventional testing. The GPP group demonstrated a higher co-infection rate (48.4% vs 13.3%; P < .001) and quicker turnaround time (23.4 vs 71.4 hours; P < .001). The GPP identified 29 potential viral infections that were undetectable by conventional stool tests. Unnecessary anti-infective therapy was avoided in 9 of 11 exclusively viral infections. Exclusively nonpathogenic parasites (n = 13) were detected by conventional stool tests, the majority of which were treated with metronidazole. There were no significant differences in clinical outcomes between groups.

Conclusions

In PWH, GPP implementation improved antibiotic stewardship through shorter turnaround times and detection of enteric viral pathogens.

INTRODUCTION: Mild traumatic brain injury (mTBI) is a heterogenous injury which can be difficult to characterize and manage. Using cross-sectional network analysis (NA) to conceptualize mTBI symptoms offers an innovative solution to identify how mTBI symptoms relate to each other. The centrality hypothesis of network theory posits that certain symptoms in a network are more relevant (central) or have above average influence over the rest of the network. However, no studies have used NA to characterize the interrelationships between symptoms in a cohort of patients who presented with mTBI to a U.S. Level 1 trauma center emergency department and how subacute central symptoms relate to long-term outcomes. METHODS: Patients with mTBI (Glasgow Coma Scale = 13-15) evaluated across 18 U.S. Level 1 trauma centers from 2013 to 2019 completed the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) at 2 weeks (W2) post-injury (n = 1,593) and at 3 months (M3), 6 months (M6), and 12 months (M12) post-injury. Network maps were developed from RPQ subscale scores at each timepoint. RPQ scores at W2 were associated with M6 and M12 functional and quality of life outcomes. RESULTS: Network structure did not differ across timepoints, indicating no difference in symptoms/factors influence on the overall symptom network across time. The cognitive factor had the highest expected influence at W2 (1.761), M3 (1.245), and M6 (1.349). Fatigue had the highest expected influence at M12 (1.275). The emotional factor was the only other node with expected influence >1 at any timepoint, indicating disproportionate influence of emotional symptoms on overall symptom burden (M3 = 1.011; M6 = 1.076). DISCUSSION: Several symptom factors at 2-weeks post-injury were more strongly associated with incomplete recovery and/or poorer injury-related quality of life at 6 and 12 months post-injury than previously validated demographic and clinical covariates. The network analysis suggests that emotional, cognitive, and fatigue symptoms may be useful treatment targets in this population due to high centrality and activating potential of the overall symptom network.

Objectives

To characterize the clinical presentation and outcome in infants <6 months of age with Kawasaki disease (KD) and to describe the use of newer anti-inflammatory therapies in this young population.

Study design

We evaluated 88 infants?<6 months old and 632??6 months old treated for KD. We compared differences in laboratory data, response to treatment, and coronary artery outcomes between the 2 cohorts. Fisher exact test was used to analyze categorical variables, whereas the Wilcoxon rank sum test was used for continuous variables.

Results

The majority of children in both cohorts were diagnosed and treated within the first 10 days of illness (median illness day 6 in both cohorts). For patients treated within the first 10 days after fever onset, a larger proportion of infants <6 months old had a dilated or aneurysmal coronary artery on the initial echocardiogram compared with those ?6 months old (43.4% vs 19.5%). Furthermore, 18.6% of infants?<6 months old who had a normal echocardiogram at diagnosis, developed a dilated or aneurysmal coronary artery on a subsequent echocardiogram within 8 weeks of diagnosis. Twenty-eight infants?<6 months old received a single dose of infliximab without any untoward effects.

Conclusions

Despite treatment in the first 10 days, infants?<6 months old with acute KD are more likely to develop coronary artery abnormalities. Thus, the development of adjunctive therapies to reduce coronary artery damage should target this population.