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ObjectiveTo characterise the transitional pulmonary physiology of infants with congenital diaphragmatic hernia (CDH) using measures of expiratory tidal volume (TV) and end-tidal carbon dioxide (ETCO2).DesignProspective single-centre observational study.SettingQuaternary neonatal intensive care unit.PatientsInfants with an antenatal diagnosis of CDH born at the Children’s Hospital of Philadelphia.InterventionsTV and ETCO2were simultaneously recorded using a respiratory function monitor (RFM) during invasive positive pressure ventilation immediately after birth.Main outcome measuresTV per birth weight and ETCO2values were summarised for each minute after birth. Subgroups of interest were defined by liver position (thoracic vs abdominal) and extracorporeal membrane oxygenation (ECMO) treatment.ResultsRFM data were available for 50 infants from intubation until a median (IQR) of 9 (7–14) min after birth. TV and ETCO2values increased for the first 10 min after birth, but intersubject values were heterogeneous. TVs were overall lower and ETCO2values higher in infants with an intrathoracic liver and infants who were ultimately treated with ECMO. On hospital discharge, survival was 88% (n=43) and 34% (n=17) of infants were treated with ECMO.ConclusionRespiratory function immediately after birth is heterogeneous for infants with CDH. Lung aeration, as evidenced by expired TV and ETCO2, appears to be ongoing throughout the first 10 min after birth during invasive positive pressure ventilation. Close attention to expired TV and ETCO2levels by 10 min after birth may provide an opportunity to optimise and individualise ventilatory support for this high-risk population.

Objectives. We determined the prevalence of first lifetime use of cigarettes during pregnancy or in the early postpartum period (incident smoking) and identified sociodemographic and health-related characteristics of incident smokers.Methods. We used statistics based on data from a longitudinal study of a large cohort of pregnant, low-income, urban women (n= 1,676) to describe the timing of first-time use and to compare incident smokers with those who had never smoked and those who had already smoked prior to pregnancy.Results. About one in 10 (10.2%) women who had not previously smoked initiated cigarette smoking during pregnancy or in the early postpartum period. Compared with those who had never smoked, incident smokers were more likely to report high levels of stress and to have elevated levels of depressive symptomatology, which may be rooted in relatively poor social and economic conditions.Conclusion. A significant number of women may be initiating smoking during pregnancy or in the early postpartum period. These women have characteristics that are consistent with the risk factors associated with smoking. Further research is warranted to determine prevalence in other populations, identify the risk factors for incident smoking, and assess the potential for primary prevention efforts designed to help women who had previously avoided cigarette use to remain smoke-free throughout pregnancy and in the postpartum period.

The dynamic mechanical analysis of short nylon-6 fibre/nanosilica-reinforced elastomeric hybrid composites was carried out over the frequency range 1–50 Hz at 70 °C. The storage modulus (E′) and loss modulus (E″) increased linearly with frequency for all the composites, irrespective of the matrix used. With the incorporation of short fibre, E′ improved uniformly over the frequency range studied. The storage modulus of the composite was greatly influenced by the incorporation of nanosilica for all the mixes. In the case of gum compound, E′ and E″ increased marginally up to 30 Hz, and beyond this the rate was high. The samples with higher fibre content showed a two-step increase in E′ and E″ with frequency. The rate of increase in E′ and E″ with silica for different samples showed that the rate was higher for samples containing nanosilica than for samples containing commercial silica. The E″ was also found to increase with increasing silica content.

Adverse childhood experiences (ACEs) are risk factors for health problems later in life. This study aims to assess the influence of ACEs on risky health behaviors among mothers-to-be and determine whether a dose response occurs between ACEs and risky behaviors.

Nanosilica was ssynthesized by acid hydrolysis of sodium silicate using dilute hydrochloric acid. The ssynthesized silica was scharacterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The particle size of silica was calculated to be 13 nm from XRD results. This synthetic nanosilica was used in place of hydrated silica in an HRH (hexamethylenetetramine, resorcinol, and silica) bonding system for a styrene–butadiene rubber (SBR)/nylon-6 short fibre composite. Nanosilica was also used as reinforcing filler in an SBR/nylon-6 short fibre hybrid composite. The cure characteristics and mechanical properties of the hybrid composites were evaluated. Minimum torque, maximum torque, and cure rate of the hybrid composites increased with silica loading. Cure time decreased with fibre loading and increased with silica content. Scorch time also decreased with fibre loading. The volume fraction of rubber in a solvent-swollen sample increased with nanosilica. Nanosilica in the rubber composites also improved the tensile strength, modulus, and tear strength to a greater extent than the conventional silica. Abrasion loss and hardness were also better for the nanosilica composites. Resilience and compression set were adversely affected. The composites showed anisotropy in mechanical properties.

The purpose of this study was to evaluate the reactivity and the effect of concentration of three tertiary amines upon the mechanical properties of a chemical curing dental composite. Chemical cured composite pastes were prepared by keeping peroxide concentration constant at 1 wt% (by weight of resin mixture) and by varying the amine/peroxide molar ratio from 0.25 to 1.5. Composite samples were prepared for all three amine pastes aged for 1, 15, 30, 45, and 60 d stored at 8, 22, and 37°C. The loss in activity of the tertiary amine with time was measured. Changes in compressive strength, diametral tensile strength, and microhardness were also measured. A sharp decrease in working and setting times corresponding to increased activity was noticed with an increased amine content. The activity was found to vary in the order NN-dimethyl p-toluidine (DMPT) > 2-(4-dimethylaminophenyl) ethanol (DMAPEA) > NNdiethanol p-toluidine (DEPT). DMPT is found to be more temperature sensitive than DMAPEA and DEPT. However, DEPT is found to provide better storage stability out of all three amines tested. Each amine was found to possess optimum concentrations at which the mechanical properties showed maximum values. DEPT is preferred for long-term storage stability in chemical-cured dental composites where aging tends to reduce the activity of the amine.