Atomic-scale age resolution of planetary events

Resolving the timing of crustal processes and meteorite impact events is central to understanding the formation, evolution and habitability of planetary bodies. However, identifying multi-stage events from complex planetary materials is highly challenging at the length scales of current isotopic techniques. Here we show that accurate U-Pb isotopic analysis of nanoscale domains of baddeleyite can be achieved by atom probe tomography. Within individual crystals of highly shocked baddeleyite from the Sudbury impact structure, three discrete nanostructural domains have been isolated yielding average ²⁰⁶Pb/²³⁸U ages of 2,436±94 Ma (protolith crystallization) from homogenous-Fe domains, 1,852±45 Ma (impact) from clustered-Fe domains and 1,412±56 Ma (tectonic metamorphism) from planar and subgrain boundary structures. Baddeleyite is a common phase in terrestrial, Martian, Lunar and asteroidal materials, meaning this atomic-scale approach holds great potential in establishing a more accurate chronology of the formation and evolution of planetary crusts.

Constraining the timing of crustal processes and impact events remains challenging. Here, the authors show that atom probe tomography can produce highly accurate U-Pb isotopic age constraints in baddeleyite crystals, which is a common phase in terrestrial, Martian, Lunar and asteroidal materials.

A Rapid Epidemiological Tool to Measure the Burden of Norovirus Infection and Disease in Resource-Limited Settings

Background

Rapid, cost-effective tools are needed to estimate the disease burden of acute gastroenteritis (AGE) and norovirus (NoV) in resource-limited settings.

Methods

Households with children (6 weeks–17 years) in rural Guatemala were randomly enrolled into 2 parallel AGE surveillance systems: (1) a prospective cohort, which included an enrollment visit followed by 1 year of prospective observation using a smartphone-based weekly symptom diary; and (2) 2 sequential cross-sectional rapid active sampling (RAS) surveys. Norovirus testing was performed during enrollment (all subjects) and for prospective AGE episodes (prospective cohort only).

Results

The prospective cohort enrolled 207 households (469 children) from April to September 2015 followed by 471 person-years of observation; RAS survey 1 enrolled 210 households (402 children) during October to November 2015, and RAS survey 2 enrolled 210 separate households (368 children) during January to February 2016. The prospective cohort detected a NoV+ AGE prevalence of 11% and a population-attributable fraction (PAF) of −1.6% at enrollment, followed by an incidence of 1.4 episodes/100 person-years. Rapid active sampling surveys 1 and 2 identified a NoV+ AGE prevalence of 14%–21% and a PAF of 3.2%–12.4%.

Conclusions

Rapid active sampling surveys were practical and identified more cases of NoV infection and disease compared with a parallel prospective cohort in rural Guatemala.

Once-Daily Ceftriaxone Plus Metronidazole Versus Ertapenem and/or Cefoxitin for Pediatric Appendicitis

BACKGROUND

Appendicitis is a common surgical emergency in pediatric patients, and broad-spectrum antibiotic therapy is warranted in their care. A simplified once-daily regimen of ceftriaxone and metronidazole (CTX plus MTZ) is cost effective in perforated patients. The goal of this evaluation is to compare a historic regimen of cefoxitin (CFX) in nonperforated cases and ertapenem (ERT) in perforated and abscessed cases with CTX plus MTZ for all cases in terms of efficacy and cost.

METHODS

A retrospective review compared outcomes of nonperforated, perforated, and abscessed cases who received the historic regimen or CTX plus MTZ. Length of stay, time to afebrile, time to full feeds, postoperative abscess, and wound infection rates, inpatient readmissions, and antibiotic costs were evaluated.

RESULTS

There were a total of 841 cases reviewed (494 nonperforated, 247 perforated, and 100 abscessed). Overall, the CTX plus MTZ group had a shorter time to afebrile (P < .001). Treatment groups did not differ in length of stay. Postoperative abscess rates were similar between groups (4.1% vs 3.3%, not significant). Other postoperative complications were similar between groups. Total antibiotic cost savings were over $110 000 during the study period (from November 2010 to June 2013).

CONCLUSIONS

Both CFX and/or ERT and CTX plus MTZ result in low abscess and complication rates, suggesting both are effective strategies. Treatment with CTX plus MTZ results in a shorter time to afebrile, while also providing significant antibiotic cost savings. Ceftriaxone plus MTZ is a streamlined, cost-effective regimen in the treatment of nonperforated, perforated, and abscessed appendicitis.

A state-wide assessment of the association between epidural analgesia, maternal fever and neonatal antibiotics in Colorado, 2007-2012

OBJECTIVE

To determine if an association exists between epidural analgesia, maternal fever and neonatal antibiotic exposure in a state-wide birth cohort.

DESIGN, SETTING AND PARTICIPANTS

We performed a retrospective cohort study of the population-based Colorado Department of Public Health and Environment birth certificate database. Data included all reported births in the state of Colorado between 2007 and 2012. Live, non-preterm, vaginal, singleton, in-hospital births were included in analysis.

EXPOSURE

Maternal epidural analgesia and maternal fever.

MAIN OUTCOMES MEASURES

Neonatal antibiotic treatment for suspected sepsis. A stratified analysis was conducted to evaluate whether epidural use was an effect modifier of the association between maternal fever and neonatal antibiotic treatment.

RESULTS

The final cohort included 261 457 births. 2.2% of women who received an epidural had a fever, as compared with 0.4% of women who did not receive an epidural (OR: 5.4; 95% CI 4.9 to 6.0), and neonates born to women who received an epidural had 1.26 times increased odds of antibiotic treatment (95% CI 1.1 to 1.4). Stratification by epidural use did not alter the association between maternal fever and neonatal antibiotic treatment.

CONCLUSIONS

Colorado providers treat neonates born to mothers with maternal fever without respect to whether the mother had an epidural. Further research into improved criteria for neonatal sepsis evaluation that accounts for the contribution of maternal epidural fever should be developed to decrease unnecessary neonatal antibiotic exposure.

Pressure balance cross-calibration method using a pressure transducer as transfer standard

Piston gauges or pressure balances are widely used to realize the SI unit of pressure, the pascal, and to calibrate pressure sensing devices. However, their calibration is time consuming and requires a lot of technical expertise. In this paper, we propose an alternate method of performing a piston gauge cross calibration that incorporates a pressure transducer as an immediate in-situ transfer standard. For a sufficiently linear transducer, the requirement to exactly balance the weights on the two pressure gauges under consideration is greatly relaxed. Our results indicate that this method can be employed without a significant increase in measurement uncertainty. Indeed, in the test case explored here, our results agreed with the traditional method within standard uncertainty, which was less than 6 parts per million.

Regulators of G protein signaling 12 promotes osteoclastogenesis in bone remodeling and pathological bone loss

Regulators of G protein signaling (Rgs) have pivotal roles in controlling various cellular processes, such as cell differentiation. How Rgs proteins regulate osteoclast (OC) differentiation, function and bone homeostasis is poorly understood. It was previously demonstrated that Rgs12, the largest protein in the Rgs family, is predominantly expressed in OCs and regulates OC differentiation in vitro. To further understand the role and mechanism of Rgs12 in OC differentiation and bone diseases in vivo, we created OC-targeted Rgs12 knockout mice by using inducible Mx1-Cre and CD11b-Cre. Deletion of Rgs12 in hematopoietic cells or specifically in OC precursors resulted in increased bone mass with decreased OC numbers. Loss of Rgs12 impaired OC differentiation and function with impaired Ca(2+) oscillations and reduced nuclear factor of activated T cells (NFAT) 2 expression. The introduction of wild-type osteoblasts did not rescue the defective osteoclastogenesis. Ectopic expression of NFAT2 rescued defective OC differentiation in CD11b;Rgs12(fl/fl) cells and promoted normal OC differentiation. Moreover, deletion of Rgs12 significantly inhibited pathological osteoclastogenesis and bone destruction in Rgs12-deficient mice that were subjected to ovariectomy and lipodysaccharide for bone loss. Thus our findings demonstrate that Rgs12 is an important regulator in OC differentiation and function and identify Rgs12 as a potential therapeutic target for osteoporosis and inflammation-induced bone loss.

Outbreak of Mycoplasma pneumoniae-Associated Stevens-Johnson Syndrome

BACKGROUND

Stevens-Johnson syndrome (SJS) is an uncommon, sporadic disease and outbreaks are rare. In November 2013, an outbreak of SJS was identified at Children's Hospital Colorado.

METHODS

Outbreak cases were children aged 5-21 with a discharge diagnosis of SJS admitted from September 1 to November 30, 2013. Medical charts were reviewed using standardized data collection forms. Respiratory specimens were tested for viruses and Mycoplasma pneumoniae (Mp) by polymerase chain reaction (PCR). We conducted a separate 4-year retrospective case-control study comparing hospitalized SJS cases with and without evidence of Mp infection.

RESULTS

During the outbreak, 8 children met SJS criteria. Median age was 11.5 years (range 8-16 years); 5 (63%) were boys and 5 (63%) were Mp-PCR-positive. Of the 5 PCR-positive children, none had preceding medication exposure, and all had radiographic pneumonia. All outbreak Mp isolates were macrolide susceptible. The retrospective case-control analysis showed that Mp-associated SJS episodes (n = 17) were more likely to have pneumonia (odds ratio [OR] 7.5, confidence interval [CI] 1.6–35.1), preceding respiratory symptoms (OR 30.0, CI 3.3–269.4) [corrected] an erythrocyte sedimentation rate ≥35 mg/dL (OR 22.8, CI 2.1-244.9), and ≤3 affected skin sites (OR 4.5, CI 1.2-17.4) than non-Mp-associated SJS episodes (n = 23).

CONCLUSIONS

We report the largest outbreak of SJS in children, which was also predominately associated with Mp infection. Mp-associated SJS was associated with a distinct clinical presentation that included less extensive skin disease, an elevated erythrocyte sedimentation rate, and evidence of a preceding respiratory infection.

Analysis of the pediatric health information system database as a surveillance tool for travel-associated infectious diseases

The Pediatric Health Information System (PHIS) database collects admission, diagnostic, and treatment data among 44 children's hospitals across the United States (U.S.) and presents an opportunity for travel-associated infectious disease (TAID) surveillance. We calculated cumulative incidence rates among children admitted to 16 PHIS hospitals for dengue, malaria, and typhoid, and pooled TAID using discharge codes from 1999 to 2012. We compared incidence rates before, during, and after the 2007-2009 economic recession. Among 16 PHIS hospitals during the study period (1999-2012), incidence of dengue and pooled TAID (malaria, dengue, typhoid fever) increased significantly, and rates of malaria and typhoid trended upward. Admissions for dengue and pooled TAIDs increased significantly among 16 children's hospitals across the United States from 1999 to 2012. The PHIS database may provide a useful surveillance tool for TAIDs among children in the United States.

Results from a community-based trial testing a community health worker asthma intervention in Puerto Rican youth in Chicago

Abstract Objective: Puerto Rican children suffer disproportionately from asthma. Project CURA tested the efficacy of a community health worker (CHW) intervention to improve use of inhaled corticosteroids (ICS) and reduce home asthma triggers in Puerto Rican youth in Chicago.

METHODS

This study employed a behavioral randomized controlled trial design with a community-based participatory research approach. Medications and technique were visually assessed; adherence was determined using dose counters. Home triggers were assessed via self-report, visual inspection and salivary cotinine. All participants received education on core asthma topics and self-management skills. Participants in the CHW arm were offered home education by the CHW in four visits over four months. The attention control arm received four newsletters covering the same topics.

RESULTS

While most of the participants had uncontrolled persistent asthma, <50% had ICS at baseline. In the CHW arms, 67% of participants received the full four-visit intervention. In the Elementary school cohort (n=51), the CHW arm had lower odds of having an ICS (OR=0.2; p=0.02) at 12-months; no differences were seen in other outcomes between arms at any time point. The only significant treatment arm difference in the high school cohort (n=50) was in inhaler technique where the CHW arm performed 18.0% more steps correct at five months (p<0.01) and 14.2% more steps correct at 12 months (p<0.01).

CONCLUSIONS

While this CHW intervention did not increase the number of participants with ICS or reduce home asthma triggers, important lessons were learned including challenges to CHW intervention fidelity and the need for CHWs to partner with clinical providers.