Teaching children pedestrian safety in virtual reality via smartphone: a noninferiority randomized clinical trial

OBJECTIVE

To evaluate whether child pedestrian safety training in a smartphone-based virtual reality (VR) environment is not inferior to training in a large, semi-immersive VR environment with demonstrated effectiveness.

METHODS

Five hundred 7- and 8-year-old children participated; 479 were randomized to one of two conditions: Learning to cross streets in a smartphone-based VR or learning in a semi-immersive kiosk VR. The systems used identical virtual environments and scenarios. At baseline, children's pedestrian skills were assessed in both VR systems and through a vehicle approach estimation task (judging speed/distance of oncoming traffic on monitor). Training in both conditions comprised at least six 30-min sessions in the randomly assigned VR platform and continued for up to 25 visits until adult-level proficiency was obtained. Following training and again 6 months later, children completed pedestrian safety assessments identical to baseline. Three outcomes were considered from assessments in each VR platform: Unsafe crossings (collisions plus close calls), time to contact (shortest time between child and oncoming simulated traffic), and missed opportunities (unselected safe opportunities to cross).

RESULTS

Participants achieved adult-level street-crossing skill through VR training. Training in a smartphone-based VR system was generally not inferior to training in a large semi-immersive VR system. There were no adverse effects.

CONCLUSIONS

Seven- and 8-year-old children can learn pedestrian safety through VR-based training, including training in a smartphone-based VR system. Combined with recent meta-analytic results, the present findings support broad implementation and dissemination of child pedestrian safety training through VR, including smartphone-based VR systems.

CITIES: Clinical trials with intercurrent events simulator

Although clinical trials are often designed with randomization and well-controlled protocols, complications will inevitably arise in the presence of intercurrent events (ICEs) such as treatment discontinuation. These can lead to missing outcome data and possibly confounding causal inference when the missingness is a function of a latent stratification of patients defined by intermediate outcomes. The pharmaceutical industry has been focused on developing new methods that can yield pertinent causal inferences in trials with ICEs. However, it is difficult to compare the properties of different methods developed in this endeavor as real-life clinical trial data cannot be easily shared to provide benchmark data sets. Furthermore, different methods consider distinct assumptions for the underlying data-generating mechanisms, and simulation studies often are customized to specific situations or methods. We develop a novel, general simulation model and corresponding Shiny application in R for clinical trials with ICEs, aptly named the Clinical Trials with Intercurrent Events Simulator (CITIES). It is formulated under the Rubin Causal Model where the considered treatment effects account for ICEs in clinical trials with repeated measures. CITIES facilitates the effective generation of data that resemble real-life clinical trials with respect to their reported summary statistics, without requiring the use of the original trial data. We illustrate the utility of CITIES via two case studies involving real-life clinical trials that demonstrate how CITIES provides a comprehensive tool for practitioners in the pharmaceutical industry to compare methods for the analysis of clinical trials with ICEs on identical, benchmark settings that resemble real-life trials.

Experimental evidence for a minimalist account of English resumptive pronouns

In this article we provide evidence for a Minimalist account of English-type resumptive pronouns. Our findings provide empirical support for syntactic theories that, like Minimalist accounts, allow for competition among derivations. According to our account, resumptive pronouns are spell-outs of traces. For reasons of economy, the resumptive pronoun surfaces only when the derivation with the trace is precluded by syntactic principles. This account predicts that resumptive pronouns should only improve violations of constraints on representation, and not violations of constraints on movement. We tested this prediction by conducting an acceptability judgment task with 36 native speakers of English. The results bore out our prediction; subjects preferred the resumptive pronoun over the trace in cases where the trace itself was illicit, but not in cases where only the movement operation was illicit.

Dose-response relationships for disposition and hepatic sequestration of polyhalogenated dibenzo-p-dioxins, dibenzofurans, and biphenyls following subchronic treatment in mice

Humans are exposed to mixtures of polyhalogenated dibenzo-p-dioxins, dibenzofurans, and biphenyls mainly through the diet. Many of these chemicals are dioxin-like and their relative toxicity is related to their ability to bind and activate the Ah receptor. The present study examines the structure-activity relationship for disposition of these chemicals in female B6C3F1 mice following subchronic exposures. Mice were treated 5 days/week for 13 weeks by oral gavage with different doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD),2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlorodibenzofuran (1-PeCDF), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), octachlorodibenzofuran (OCDF), 3,3',4,4',5-pentachlorobiphenyl (126), 3,3',4,4',5,5'-hexachlorobiphenyl (169), 2,3,3',4,4'-pentachlorobiphenyl (105), 2,3',4,4',5-pentachlorobiphenyl (118), and 2,3,3',4,4',5-hexachlorobiphenyl (156). All of the chemicals examined exhibited dose-dependent increases in the liver/fat concentrations except PCBs 105, 118, and 156. While TCDD is the most potent toxicant in this class of chemicals, 4-PeCDF, PeCDD, OCDF, TCDF, and PCB126 were sequestered in hepatic tissue to a greater extent than was TCDD. The high affinity for hepatic tissue supports the presence of an inducible hepatic binding protein for some dixin-like chemicals. The differences in disposition between these chemicals suggests that pharmacokinetic differences between congeners is important in the relative potency of these chemicals.

Relatives children say

In an experiment designed to elicit restrictive relatives clauses, 28 children ranging in age from 2; 2 to 3; 10 provided a corpus of communicatively appropriate relative clauses. In evaluating this corpus, we found that most children produced mostly adult relative clauses most of the time. Detailed study of these utterances uncovered a few error patterns, which we analyzed in light of several considerations (e.g. the overall frequency of an error type, its distribution across children and items, its relation to the construction under study, and the similarity of the error to what children do elsewhere). Only one error pattern, namely some children's production of inappropriate relative pronouns, is argued to reflect a systematic feature of language development. We conclude that children's ability to represent the syntactic structure of the embedded clause is on target very early.

Determination of 2,3,7,8-chlorine-substituted dibenzo-p-dioxins and -furans at the part per trillion level in United States beef fat using high-resolution gas chromatography/high-resolution mass spectrometry

As part of the U.S. EPA Dioxin Reassessment Program, the 2,3,7,8-chlorine-substituted dibenzo-p-dioxins and furans were measured at part per trillion (ppt) levels in beef fat collected from slaughter facilities in the United States. This is the first statistically designed national survey of these compounds in the U.S. beef supply. Analyte concentrations were determined by high-resolution gas chromatography/high-resolution mass spectrometry, using isotope dilution methodology. Method limits of detection on a whole weight basis were 0.05 ppt for TCDD and 0.10 ppt for TCDF, 0.50 ppt for the pentas (PeCDDs/PeCDFs)/hexas (HxCDDs/HxCDFs)/heptas (HpCDDs/HpCDFs), and 3.00 ppt for the octas (OCDD/OCDF). Method detection and quantitation limits were established on the basis of demonstrated performance criteria utilizing fortified samples rather than by conventional signal-to-noise or variability of response methods. The background subtraction procedures developed for this study minimized the likelihood of false positives and increased the confidence associated with reported values near the detection limits. Mean and median values for each of the 2,3,7,8-Cl-substituted dioxins and furans are reported, along with the supporting information required for their interpretation. The mean toxic equivalence values for the samples are 0.35 ppt (nondetects = 0) and 0.89 ppt (nondetects = 1/2 LOD).

Hypothyroidism--a possible etiology of open-angle glaucoma

BACKGROUND

Recent studies have shown an association between hypothyroidism and primary open-angle glaucoma (POAG). When hypothyroidism occurs, accumulation of hyaluronic acid within the trabecular meshwork may cause an increase in outflow resistance and intraocular pressure (IOP). This increase may be reversible with use of systemic treatment.

METHODS

A hypothyroid patient is described whose IOP inversely varied with the use or the discontinuation of systemic hypothyroid medications.

RESULTS

The patient's IOP was controlled when she complied with systemic treatment.

CONCLUSIONS

In some cases, hypothyroidism may contribute to the genesis of open-angle glaucoma. Systemic treatment alone may be adequate to prevent progression of a glaucomatous diseased state. It may be prudent to investigate the presence of undiagnosed hypothyroidism in individuals with poorly controlled POAG, in individuals with normal-tension glaucoma, and in newly diagnosed cases.

A statistical survey of dioxin-like compounds in United States beef: a progress report

The USEPA and the USDA have completed the first statistically designed survey of the occurrence and concentration of CDDs and CDFs in the fat of beef animals raised for human consumption in the United States. Back fat was sampled from 63 carcasses at federally inspected slaughter establishments nationwide. The sample design called for sampling beef animal classes in proportion to national annual slaughter statistics. All samples were analyzed using a modification of EPA method 1613, using isotope dilution, High Resolution GC/MS to determine the rate of occurrence of 2,3,7,8-substituted CDDs/CDFS. The whole weight method detection limits ranged from 0.05 ng kg-1 for TCDD to 3 ng kg-1 for OCDD. The results of this survey showed a mean concentration (reported as I-TEQ, lipid adjusted) in U.S. beef animals of 0.35 ng kg-1 and 0.89 ng kg-1 when either non-detects are treated as 0 value or assigned a value of 1/2 the detection limit, respectively.

In vitro and in vivo evaluations of A-80556, a new fluoroquinolone

A-80556 is a novel fluoroquinolone with potent antibacterial activity against gram-positive, gram-negative, and anaerobic organisms. A-80556 was more active than ciprofloxacin, ofloxacin, lomefloxacin, and sparfloxacin against gram-positive bacteria. A-80556 was particularly active against Staphylococcus aureus (MIC for 90% of isolates [MIC90], 0.12 microgram/ml, relative to fluoroquinolone-susceptible strains) and Streptococcus pneumoniae (MIC90, 0.12 microgram/ml). A-80556 was also the most active of the quinolones tested against ciprofloxacin-resistant S. aureus, with an MIC90 of 4.0 micrograms/ml; that of ciprofloxacin was > 128 micrograms/ml. However, the significance of this activity is not known. A-80556 was slightly less active against Escherichia coli (MIC90, 0.06 microgram/ml) and other enteric organisms than ciprofloxacin (MIC90 for E. coli, < or = 0.03 microgram/ml). A-80556 was slightly less active against Pseudomonas aeruginosa (MIC90, 4.0 micrograms/ml) than ciprofloxacin (MIC90, 2.0 micrograms/ml) and more active against Acinetobacter spp. (respective MIC90s, 0.12 and 0.5 microgram/ml). A-80556 was also the most active compound against anaerobes. Against Bacteroides fragilis, the MIC90 of A-80556 was 2.0 micrograms/ml; that of ciprofloxacin was 16 micrograms/ml. The in vivo efficacy of A-80556 in experimental models with both gram-positive and gram-negative infections was consistent with the in vitro activity and pharmacokinetics and oral absorption in mice.

Basal-level expression of the yeast HSP82 gene requires a heat shock regulatory element

Previous studies have shown that heat shock factor is constitutively bound to heat shock elements in Saccharomyces cerevisiae. We demonstrate that mutation of the heat shock element closest to the TATA box of the yeast HSP82 promoter abolishes basal-level transcription without markedly affecting inducibility. The mutated heat shock element no longer bound putative heat shock factor, either in vitro or in vivo, but still resided within a nuclease-hypersensitive site in the chromatin. Thus, constitutive binding of heat shock factor to heat shock elements in S. cerevisiae appears to functionally direct basal-level transcription.

In vitro and in vivo activities of clarithromycin against Mycobacterium avium

There is no effective therapy to treat Mycobacterium avium complex infection in patients with acquired immune deficiency syndrome. Clarithromycin (A-56268; TE-031) is a new macrolide which is twofold more active than erythromycin against most aerobic bacteria. In addition, higher levels in serum and tissue are achieved with clarithromycin than with erythromycin. In this study, clarithromycin, erythromycin, difloxacin, temafloxacin, ciprofloxacin, rifampin, amikacin, and ethambutol were tested in vitro and in vivo against the M. avium complex. The MICs for 90% of strains tested were 4 micrograms/ml for clarithromycin, 64 micrograms/ml for erythromycin, 32 micrograms/ml for difloxacin, 8 micrograms/ml for temafloxacin, 4 micrograms/ml for ciprofloxacin, 4 micrograms/ml for rifampin, 32 micrograms/ml for amikacin, and 32 micrograms/ml for ethambutol. Beige mice were infected intravenously with 10(7) CFU of M. avium ATCC 25291. Treatment was started on day 6 after infection and was administered twice a day at 8-h intervals for 9 days. Clarithromycin was the most effective compound in these tests and was effective in reducing the viable bacterial counts in the spleen when it was administered subcutaneously or orally at a dose of 25 mg/kg. Amikacin was the only other compound which showed activity in vivo. The peak concentration in serum at which clarithromycin was active was approximately 1.0 microgram/ml.

Coumamidines, new broad spectrum antibiotics of the cinodine type. III. Microbiologic activity of coumamidine gamma 1

The coumamidines are novel antibiotics with activity against a wide spectrum of aerobic Gram-positive and Gram-negative bacteria. All microbiological studies were performed on coumamidine gamma 1. The MIC90s (micrograms/ml) of coumamidine are as follows: Staphylococcus aureus 1.0, Streptococcus pyogenes 8, Enterobacteriaceae 2.0, Pseudomonas aeruginosa 8, Campylobacter jejuni and Campylobacter coli 1, Legionella pneumophila 8, Haemophilus influenzae 0.5, Neisseria gonorrhoeae 0.5. Coumamidine had MICs ranging from 8 to greater 0.5, Neisseria gonorrhoeae 0.5. Coumamidine had MICs ranging from 8 to greater than 64 for most anaerobes, except some Peptostreptococcus strains. The aminoglycoside super-sensitive strain, P. aeruginosa BMH 10, was also super-sensitive to coumamidine (MIC 0.2 micrograms/ml). Coumamidine was rapidly bactericidal for S. aureus. The viable bacterial count in logarithmic phase cultures was reduced to less than 10 cfu within 2 hours after exposure to 4 times the MIC (3.12 micrograms/ml) of coumamidine. The frequency of resistance development was less than 1 X 10(-9) for Escherichia coli and S. aureus when selected at 4 and 8 times the MIC. The Cmax in mouse serum after a single subcutaneous dose of 25 mg/kg of coumamidine was 4.5 micrograms/ml and t1/2 was 1 hour. Coumamidine is stable in serum. In mouse protection tests against S. aureus NCTC 10649 the ED50 was less than 0.6 mg/kg/day when it was administered subcutaneously at 1 and 5 hours after infection. Coumamidine was not absorbed after oral administration. The antibacterial spectrum, bactericidal activity, stability in serum and low frequency of resistance make this an interesting new class of antibiotics.

Histiocytosis X and acute monocytic leukemia. Biologic illustration of the monocyte phagocytic system

The concept of a mononuclear phagocytic system consisting of a continuum of cells arising from the bone marrow monoblast and terminating in the mature tissue macrophage is being actively investigated. The presentation of documented acute monocytic leukemia 18 months following the confirmed diagnosis of histiocytosis X in a 39-year-old man strongly supports the concept of the mononuclear phagocytic system lineage.

Digital subtraction angiography of the extremities using table translation

Digital subtraction angiography (DSA) of the extremities has been performed with both intravenous and intraarterial injections of contrast material. Intravenous studies are usually site specific and are limited by contrast material load; a complete intraarterial study with multiple injections of contrast material may be time consuming. A feasibility study to evaluate a DSA technique that would allow table translation and imaging of two contiguous regions following a single injection of contrast material--bolus-chase DSA--was performed. Forty-five examinations were performed, 13 intravenously and 32 intraarterially. Twelve intravenous and 16 intraarterial DSA examinations were totally satisfactory. Inadequate studies were predominantly caused by slow arterial clearance of contrast material in the distal calf and by operator error. Compared with conventional DSA, anatomic studies of lower-extremity vessels could be obtained faster and with lower contrast material loads using bolus-chase DSA.

Similar effects by valine and isoleucine on threonine deaminase

Isoleucine is known to be a very effective inhibitor and stabilizer of threonine deaminase. In contrast, valine has been reported to be a positive effector for the enzyme by action on a separate site. However, the apparent increase in activity caused by valine is due to stabilization of the enzyme. When stabilization is accomplished by other means, valine exerts only an inhibitory effect. Thus, valine, like isoleucine, both stabilizes and inhibits threonine deaminase and may well do so via the isoleucine site on the enzyme.