Correction: CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge.

[This corrects the article DOI: 10.1371/journal.pone.0183456.].

CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge.

The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.

Changing antiepileptic drug use for seizures in US neonatal intensive care units from 2005 to 2014.

OBJECTIVE: Neonatal seizures are a common problem in the neonatal intensive care unit and are frequently treated with antiepileptic drugs. Limited data exist on current or changing antiepileptic drug use for seizures in the neonatal intensive care unit.We sought to describe trends of antiepileptic drug exposure in a large volume of US neonatal intensive care unit from 2005 to 2014 and we hypothesized increasing levetiracetam exposure over the 10-year study period. STUDY DESIGN: Retrospective cohort study of infants from the Pediatrix Medical Group Clinical Data Warehouse, a large, multicenter, deidentified data set. Data were analyzed for trends in 2-year time periods. Our cohort included infants with a diagnosis of seizures who received an antiepileptic drug that were discharged from the neonatal intensive care unit from 1 January 2005 to 31 December 2014. RESULTS: Among 778 395 infants from 341 facilities, we identified 9134 infants with a seizure diagnosis who received an antiepileptic drug. Phenobarbital was used in 98% of the cohort. From 2005-2006 to 2013-2014 phenobarbital exposure declined from 99 to 96% (P<0.001), phenytoin exposure decreased from 15 to 11% (P<0.001) and levetiracetam exposure increased 10-fold from 1.4 to 14% (P<0.001). Overall, <1% of infants were exposed to carbamazepine, lidocaine or topiramate. CONCLUSIONS: Infants with seizures were overwhelmingly exposed to phenobarbital, despite a significant increase in levetiracetam exposure. The use of phenytoin declined and has been surpassed by levetiracetam as the second most widely used antiepileptic in the neonatal intensive care unit. These changes in antiepileptic drug usage patterns have occurred in the absence of novel efficacy data in neonates.

Turbulence Model Selection for Low Reynolds Number Flows.

One of the major flow phenomena associated with low Reynolds number flow is the formation of separation bubbles on an airfoil's surface. NACA4415 airfoil is commonly used in wind turbines and UAV applications. The stall characteristics are gradual compared to thin airfoils. The primary criterion set for this work is the capture of laminar separation bubble. Flow is simulated for a Reynolds number of 120,000. The numerical analysis carried out shows the advantages and disadvantages of a few turbulence models. The turbulence models tested were: one equation Spallart Allmars (S-A), two equation SST K-ω, three equation Intermittency (γ) SST, k-kl-ω and finally, the four equation transition γ-Reθ SST. However, the variation in flow physics differs between these turbulence models. Procedure to establish the accuracy of the simulation, in accord with previous experimental results, has been discussed in detail.

Recurrent paediatric supratentorial extraventricular ependymoma associated with genetic mutation at exon 4 of p53 gene.

Recurrent supratentorial extraventricular ependymoma in a four-year-old Malay boy treated twice surgically in combination with cranial radiotherapy is reported. He presented with symptoms of raised intracranial pressure and a history of focal seizure. Computed tomography of the brain showed a left supratentorial extraventricular cystic lesion causing a mass effect. The tumour histology was ependymoma (WHO grade II). The clinical course, radiological characteristics and management of this tumour are discussed. Molecular genetic analysis of p53 and p27 genes revealed substitution of nucleotide G to C at location nucleotide 12139, exon 4 of gene p53. No alteration was detected at exon 5-6 and 8 of p53 gene and exon 1 and 2 of p27 gene.

Delayed glial cell death following wallerian degeneration in white matter tracts after spinal cord dorsal column cordotomy in adult rats.

The devastating consequences of spinal cord injury (SCI) result primarily from damage to long tracts in the spinal white matter. To elucidate the secondary injury processes occurring after SCI, we investigated the relationship between apoptosis and Wallerian degeneration in spinal white matter tracts. In the rat spinal cord, the corticospinal tract (CST) and the dorsal ascending tract (DAT) are separated from each other in the dorsal column and relay information in opposite directions. A dorsal column cordotomy at the eighth thoracic (T8) level simultaneously induces Wallerian degeneration in the CST caudal to and in the DAT rostral to the injury. Using the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method, we demonstrate that apoptosis occurred in areas of Wallerian degeneration in both tracts throughout the length of the cord segments studied (from T3 to T12). This delayed cell death, more apparent in the DAT, began at 7 days after injury and peaked at 14 days for the DAT and 28 days for the CST. Although a few TUNEL+ cells, slightly above the noninjury control level, were found in intact areas of both tracts, statistically significant differences in the number of TUNEL+ cells were found between the intact and the lesioned tract segments (CST, F < 0.01; DAT, F < 0.001). Within a particular spinal segment, a mean number of 64 and 939 TUNEL+ cells in the degenerating CST and DAT, respectively, were estimated stereologically at 14 days postinjury. TUNEL+ cells in degenerating tracts outnumber their intact counterparts by 3.8:1 in the CST and 4.1:1 in the DAT, although a statistically significant difference between the two was only found in the DAT at this time point (P < 0.05). Finally, we demonstrated that oligodendrocytes, the myelin-forming cells in the central nervous system, constitute at least a portion of the cells undergoing apoptosis within areas of Wallerian degeneration.

Evolution of a new device for the prevention of pulmonary embolism.

The embolus trap (ET) is a new device that interrupts the inferior vena cava (IVC) for the prevention of pulmonary embolism. It has a central column from which six wires extend in two tiers. The adjacent wires are formed into loops with hooks at the distal ends that grip the vein wall. Each tier contains three wire loops, and the loops are staggered circumferentially between the tiers. The ET was implanted into the IVC in 26 dogs via a femoral or jugular venotomy. IVC patency was evaluated by venacavagrams. Autologous clots were embolized via the femoral vein to test the efficacy of the ET. The animals were followed for 1 to 4 months prior to postmortem examination. The ET remained patent in all animals and consistently trapped the thromboemboli while preserving blood flow. Lysis of the trapped emboli was observed in 4 to 6 weeks. There was no evidence of malpositioning, penetration through the vein wall, or migration of the ET.