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Titanium compounds have demonstrated great interfacial properties with biological tissues whereas a wide variety of polyurethanes have also been successfully probed in medical applications. However, studies about hybrids based on polyurethanes/TiO 2 for medical applications are scarce. The aim of this work is to design novel biodegradable hybrid materials based on polyurethanes/TiO 2 (80% organic–20% inorganic) and to perform a preliminary study of the potential applications in bone regeneration. The hybrids have been prepared by a sol-gel reaction using titanium isopropoxide as precursor of the inorganic component and polyurethane as the organic one. A series of polyurethanes has been prepared using different polyesters glycol succinate as soft segment, and 1,6-diisocyanatohexane (HDI) and butanediol (BD) as linear hard segment. The spectroscopy techniques used allow to confirm the formation of the required polyurethanes by the identification of bands related to carboxylic groups ( COOH), and the amine groups ( NH ), and also the Ti OH bonds and the bonds related to the interconnected network between the inorganic and the organic components from hybrids. The results from SEM/EDS show a homogeneous distribution of the inorganic component into the organic matrix. The nontoxic character of the hybrid (H400) was probed using MG-63 cell line with over 90% of cell viability. Finally, the formation of a hydroxyapatite layer in the material surface after 21 days of soaking in SBF shows the bioactive character. [ABSTRACT FROM AUTHOR]

The accuracy of density measurements and position resolution in flash (40 ns) radiography of thick objects with 24 Gev/c protons is investigated. A global model fit to step wedge data is shown to give a good description spanning the periodic table. The parameters obtained from the step wedge data are used to predict transmission through the French Test Object (FTO), a test object of nested spheres, to a precision better than 1%. Multiple trials have been used to show that the systematic errors are less than 2%. Absolute agreement between the average radiographic measurements of the density and the known density is 1%. Spatial resolution has been measured to be 200 μm at the center of the FTO. These data verify expectations of the benefits provided by high energy hadron radiography for thick objects. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To determine the capillary partial pressure of carbon dioxide (PCO(2)) and room air transcutaneous hemoglobin saturation (RA SAT) at 36 weeks' postmenstrual age (PMA) in infants born with weight between 501 and 1250 g. STUDY DESIGN: Multicenter, prospective investigation with primary data collection within 72 h of 36 weeks PMA or discharge, whichever first. PCO(2) and RA SAT determinations were done at rest on infants not requiring mechanical ventilation or nasal continuous positive airway pressure (NCPAP). RESULT: A total of 220 infants were enrolled (mean gestational age 27.7 weeks, mean birthweight 951 g). In infants with traditionally defined chronic lung disease (CLD) compared to those without CLD, the mean PCO(2) was significantly higher (54 versus 45 mm Hg) and the median RA SAT significantly lower (<80 versus 97%). In infants with the new classification of bronchopulmonary dysplasia (BPD), there was a significant linear trend toward increasing PCO(2) with increasing severity of BPD (45, 47, 54 and 62 mm Hg in No, Mild, Moderate and Severe BPD). There was a significant linear trend toward decreasing RA SAT with increasing severity of BPD (97, 95 <80, <80% in No, Mild, Moderate and Severe BPD). CONCLUSION: Defining CLD as BPD based upon a RA SAT test is a more discriminate, objective method to categorize lung injury. PCO(2) is an objective measure of lung function that inversely correlates with RA SAT. These determinations done together at 36 weeks PMA may provide more precise and accurate estimates of lung injury that might allow for better understanding of pulmonary therapies and clearer comparison of BPD rates and severities among NICUs. [ABSTRACT FROM AUTHOR]

Objective:To determine the capillary partial pressure of carbon dioxide (PCO2) and room air transcutaneous hemoglobin saturation (RA SAT) at 36 weeks’ postmenstrual age (PMA) in infants born with weight between 501 and 1250 g.Study Design:Multicenter, prospective investigation with primary data collection within 72 h of 36 weeks PMA or discharge, whichever first. PCO2 and RA SAT determinations were done at rest on infants not requiring mechanical ventilation or nasal continuous positive airway pressure (NCPAP).Result:A total of 220 infants were enrolled (mean gestational age 27.7 weeks, mean birthweight 951 g). In infants with traditionally defined chronic lung disease (CLD) compared to those without CLD, the mean PCO2 was significantly higher (54 versus 45 mm Hg) and the median RA SAT significantly lower (<80 versus 97%). In infants with the new classification of bronchopulmonary dysplasia (BPD), there was a significant linear trend toward increasing PCO2 with increasing severity of BPD (45, 47, 54 and 62 mm Hg in No, Mild, Moderate and Severe BPD). There was a significant linear trend toward decreasing RA SAT with increasing severity of BPD (97, 95 <80, <80% in No, Mild, Moderate and Severe BPD).Conclusion:Defining CLD as BPD based upon a RA SAT test is a more discriminate, objective method to categorize lung injury. PCO2 is an objective measure of lung function that inversely correlates with RA SAT. These determinations done together at 36 weeks PMA may provide more precise and accurate estimates of lung injury that might allow for better understanding of pulmonary therapies and clearer comparison of BPD rates and severities among NICUs.Journal of Perinatology (2008) 28, 48–54; doi:10.1038/sj.jp.7211859; published online 22 November 2007 [ABSTRACT FROM AUTHOR]

When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2-kA, 17-MeV electron beam in a 1600-ns flat-top pulse. In initial tests, DARHT-II accelerated beams with current pulse lengths from 500 to 1200 ns full-width at half-maximum (FWHM) with more than 1.2-kA, 12.5-MeV peak current and energy. Experiments have now been done with a ∼1600-ns pulse length. These pulse lengths are all significantly longer than any other multimegaelectronvolt LIA, and they define a novel regime for high-current beam dynamics, especially with regard to beam stability. Although the initial tests demonstrated insignificant beam-breakup instability (BBU), the pulse length was too short to determine whether ion-hose instability would be present toward the end of a long, 1600-ns pulse. The 1600-ns pulse experiments reported here resolved these issues for the long-pulse DARHT-II LIA. [ABSTRACT FROM PUBLISHER]

The DARHT-II linear-induction accelerator has been successfully operated at 1.2-1.3 kA and 12.5-12.7 MeV to demonstrate the production and acceleration of an electron beam. Beam pulse lengths for these experiments were varied from 0.5 ps to 1.2 ps full-width half-maximum. A low-frequency inductance-capacitance (LC) oscillation of diode voltage and current resulted in an oscillation of the beam position through interaction with an accidental (static) magnetic dipole in the diode region. There was no growth in the amplitude of this oscillation after propagating more than 44 m through the accelerator, and there was no loss of beam current that could be measured. The results of these initial experiments are presented in this paper. [ABSTRACT FROM AUTHOR]

A neutron imaging diagnostic has recently been commissioned at the National Ignition Facility (NIF). This new system is an important diagnostic tool for inertial fusion studies at the NIF for measuring the size and shape of the burning DT plasma during the ignition stage of Inertial Confinement Fusion (ICF) implosions. The imaging technique utilizes a pinhole neutron aperture, placed between the neutron source and a neutron detector. The detection system measures the two dimensional distribution of neutrons passing through the pinhole. This diagnostic has been designed to collect two images at two times. The long flight path for this diagnostic, 28 m, results in a chromatic separation of the neutrons, allowing the independently timed images to measure the source distribution for two neutron energies. Typically the first image measures the distribution of the 14 MeV neutrons and the second image of the 6-12 MeV neutrons. The combination of these two images has provided data on the size and shape of the burning plasma within the compressed capsule, as well as a measure of the quantity and spatial distribution of the cold fuel surrounding this core. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The purpose of this article is to describe how a neonatal intensive care unit (NICU) was able to reduce substantially the use of postnatal dexamethasone in infants born between 501 and 1250 g while at the same time implementing a group of potentially better practices (PBPs) in an attempt to decrease the incidence and severity of chronic lung disease (CLD). METHODS: This study was both a retrospective chart review and an ongoing multicenter evidence-based investigation associated with the Vermont Oxford Network Neonatal Intensive Care Quality Improvement Collaborative (NIC/Q 2000). The NICU specifically made the reduction of CLD and dexamethasone use a priority and thus formulated a list of PBPs that could improve clinical outcomes across 3 time periods: era 1, standard NICU care that antedated the quality improvement project; era 2, gradual implementation of the PBPs; and era 3, full implementation of the PBPs. All infants who had a birth weight between 501 and 1250 g and were admitted to the NICU during the 3 study eras were included (era 1, n = 134; era 2, n = 73; era 3, n = 83). As part of the NIC/Q 2000 process, the NICU implemented 3 primary PBPs to improve clinical outcomes related to pulmonary disease: 1) gentle, low tidal volume resuscitation and ventilation, permissive hypercarbia, increased use of nasal continuous positive airway pressure; 2) decreased use of postnatal dexamethasone; and 3) vitamin A administration. The total dexamethasone use, the incidence of CLD, and the mortality rate were the primary outcomes of interest. Secondary outcomes included the severity of CLD, total ventilator and nasal continuous positive airway pressure days, grades 3 and 4 intracranial hemorrhage, periventricular leukomalacia, stages 3 and 4 retinopathy of prematurity, necrotizing enterocolitis, pneumothorax, length of stay, late-onset sepsis, and pneumonia. RESULTS: The percentage of infants who received dexamethasone during their NICU admission decreased from 49% in era 1 to 22% in era 3. Of those who received dexamethasone, the median number of days of exposure dropped from 23.0 in era 1 to 6.5 in era 3. The median total NICU exposure to dexamethasone in infants who received at least 1 dose declined from 3.5 mg/kg in era 1 to 0.9 mg/kg in era 3. The overall amount of dexamethasone administered per total patient population decreased 85% from era 1 to era 3. CLD was seen in 22% of infants in era 1 and 28% in era 3, a nonsignificant increase. The severity of CLD did not significantly change across the 3 eras, neither did the mortality rate. We observed a significant reduction in the use of mechanical ventilation as well as a decline in the incidence of late-onset sepsis and pneumonia, with no other significant change in morbidities or length of stay. CONCLUSIONS: Postnatal dexamethasone use in premature infants born between 501 and 1250 g can be sharply curtailed without a significant worsening in a broad range of clinical outcomes. Although a modest, nonsignificant trend was observed toward a greater number of infants needing supplemental oxygen at 36 weeks' postmenstrual age, the severity of CLD did not increase, the mortality rate did not rise, length of stay did not increase, and other benefits such as decreased use of mechanical ventilation and fewer episodes of nosocomial infection were documented. [ABSTRACT FROM AUTHOR]