Tracheal agenesis: A report of two cases.

Tracheal agenesis is an extremely rare congenital anomaly involving the respiratory system. It is generally associated with anomalies of other systems. Antenatal diagnosis of this condition is difficult; therefore, it presents as a medical emergency in the labor room. Intubation in these babies is difficult. As many of these babies are born prematurely, respiratory distress syndrome (RDS) adds to the management difficulties. Here, we describe two babies with this lethal anomaly and RDS where esophageal intubation and surfactant therapy proved beneficial. Furthermore, described are other associated anomalies.

The interfacial strength of carbon nanofiber epoxy composite using single fiber pullout experiments.

Carbon nanotubes and nanofibers are extensively researched as reinforcing agents in nanocomposites for their multifunctionality, light weight and high strength. However, it is the interface between the nanofiber and the matrix that dictates the overall properties of the nanocomposite. The current trend is to measure elastic properties of the bulk nanocomposite and then compare them with theoretical models to extract the information on the interfacial strength. The ideal experiment is single fiber pullout from the matrix because it directly measures the interfacial strength. However, the technique is difficult to apply to nanocomposites because of the small size of the fibers and the requirement for high resolution force and displacement sensing. We present an experimental technique for measuring the interfacial strength of nanofiber-reinforced composites using the single fiber pullout technique and demonstrate the technique for a carbon nanofiber-reinforced epoxy composite. The experiment is performed in situ in a scanning electron microscope and the interfacial strength for the epoxy composite was measured to be 170 MPa.

A validated HPLC-MS/MS method for estimating the concentration of the ganglioside, GD2, in human plasma or serum.

GD2 is a ganglioside found in the plasma membrane of the neural crest-derived cancer, neuroblastoma. GD2 is shed into the circulation of patients with neuroblastoma and could serve as a tumor biomarker to monitor tumor burden or response to treatment. We developed and validated a high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method to quantify the D18:1-18:0 (C18) and the D18:1-20:0 (C20) lipoforms of GD2 in human plasma and serum. Human brain derived GD2 containing a mixture of C18 and C20 was used as the analytical standard. Samples were extracted with methanol containing dueterated-GM1 (internal standard), and analytes were separated on a Phenomenex Kinetex C18 column eluted with a gradient mobile phase composed of ammonium acetate buffer, methanol and isopropanol. An AB Sciex 4500 QTRAP mass spectrometer in negative ion mode was used to quantify the doubly charged GD2 C18 and C20 lipoform precursor ions (m/z 836.8 and m/z 850.8) that both yield a product ion of m/z 290.0. The calibration curves were linear from 4-1000 ng/mL and 6-1500 ng/mL for GD2 C18 and C20 lipoforms respectively. Inter-day and intra-day accuracy were within the acceptable validation range in plasma and serum.

Vigilance monitoring for operator safety: A simulation study on highway driving.

INTRODUCTION: Alertness of individuals operating vehicles, aircrafts, and machinery is a pre-requisite for safety of the individual and for avoiding economic losses. In this paper, we present a new technique for determining the alertness level of the operator and elaborate the methodology for the specific case of highway driving METHOD: Our hypothesis is that the time derivative of force exerted by the driver at the vehicle-human interfaces can be used to construct a signature of individual driving styles and to discern different levels of alertness RESULTS: In this study, we present experimental results corroborating this hypothesis and introduce a parameter, 'spikiness index,' for the time series data of the force derivative to quantify driver alertness IMPACT ON INDUSTRY: The low cost, ruggedness, and low-volume data processing requirements of the proposed technique give it a competitive edge over existing predominantly image processing based vigilance monitoring systems.

Toxicities of busulfan/melphalan versus carboplatin/etoposide/melphalan for high-dose chemotherapy with stem cell rescue for high-risk neuroblastoma.

The optimal autologous stem cell rescue (HDC-SCR) regimen for children with high-risk neuroblastoma (HR-NBL) is not defined. Carboplatin/etoposide/melphalan (CEM) is the current US standard; however, European data suggest busulfan/melphalan (Bu/Mel) may have less toxicity. Published data regarding toxicities associated with CEM and Bu/Mel are limited. We conducted a single-institution retrospective cohort study of children with HR-NBL who received CEM or Bu/Mel preparative regimens. Toxicity data were analyzed using χ(2) or Fisher's exact, Wilcoxon two-sample or log-rank tests. Sinusoidal obstruction syndrome (SOS) was observed in 7/44 CEM (15.9%) and 5/21 (24%) Bu/Mel patients (P=0.50). Median time to SOS was longer following Bu/Mel than CEM (20 versus 9 days, P=0.02). Pulmonary hypertension (PHTN) was observed in ~20% of children after Bu/Mel and none after CEM (P=0.01). CEM patients had more nephrotoxicity (P=0.001), packed red blood cell (P=0.02) and platelet transfusions (P=0.008), and days on maximum pain support (P=0.0007). Time to engraftment, length of stay, documented infection rates and HDC-SCR-related mortality were similar. Nephrotoxicity and resource utilization associated with cytopenias and mucositis were greater after CEM. Pulmonary toxicities were more severe after Bu/Mel, and increased vigilance for PHTN may be warranted, particularly in children with hypoxemia out of proportion to respiratory distress.