Strategies for gallium removal after focused ion beam patterning of ferroelectric oxide nanostructures.

As part of a study into the properties of ferroelectric single crystals at nanoscale dimensions, the effects that focused ion beam (FIB) processing can have, in terms of structural damage and ion implantation, on perovskite oxide materials has been examined, and a post-processing procedure developed to remove such effects. Single crystal material of the perovskite ferroelectric barium titanate (BaTiO(3)) has been patterned into thin film lamellae structures using a FIB microscope. Previous work had shown that FIB patterning induced gallium impregnation and associated creation of amorphous layers in a surface region of the single crystal material some 20 nm thick, but that both recrystallization and expulsion of gallium could be achieved through thermal annealing in air. Here we confirm this observation, but find that thermally induced gallium expulsion is associated with the formation of gallium-rich platelets on the surface of the annealed material. These platelets are thought to be gallium oxide. Etching using nitric and hydrochloric acids had no effect on the gallium-rich platelets. Effective platelet removal involved thermal annealing at 700 degrees C for 1 h in a vacuum followed by 1 h in oxygen, and then a post-annealing low-power plasma clean in an Ar/O atmosphere. Similar processing is likely to be necessary for the full recovery of post FIB-milled nanostructures in oxide ceramic systems in general.

Spina bifida outcome: a 25-year prospective.

BACKGROUND: Open spina bifida is the most complex congenital abnormality compatible with long-term survival. This report outlines the 20- to 25-year outcome for our original cohort of patients with a myelomeningocele treated in a nonselective, prospective manner. METHODS: Of the initial 118 children, 71 patients were available for our most recent review. Nineteen patients have been lost to follow-up and 28 patients have died. Data were collected on: motor level, shunt status, education/employment, seizure history, mobility, bladder/bowel continence, tethered cord, scoliosis, latex allergy, posterior cervical decompression, tracheostomy and/or gastrostomy tube. RESULTS: Mortality (24%) continues to climb into young adulthood. Eighty-six percent of the cohort have cerebrospinal fluid diversion, with 95% having undergone at least one shunt revision. Thirty-two percent have undergone a tethered cord release, with 97% having an improvement or stabilization in their preoperative symptoms. Forty-nine percent have scoliosis, with 43% eventually requiring a spinal fusion. Sixteen patients (23%) have had at least one seizure. Eighty-five percent are attending or have graduated from high school and/or college. More than 80% of young adults have social bladder continence. Approximately 1/3 of patients are allergic to latex, with 6 patients having experienced a life-threatening reaction. CONCLUSION: At least 75% of children born with a myelomeningocele can be expected to reach their early adult years. Late deterioration is common. One of the greatest challenges in medicine today is establishing a network of care for these adults with spina bifida.

Regional brain tissue pressure gradients created by expanding extradural temporal mass lesion.

A porcine model of regional intracranial pressure was used to compare regional brain tissue pressure (RBTP) changes during expansion of an extradural temporal mass lesion. Measurements of RBTP were obtained by placing fiberoptic intraparenchymal pressure monitors in the right and left frontal lobes (RF and LF), right and left temporal lobes (RT and LT), midbrain (MB), and cerebellum (CB). During expansion of the right temporal mass, significant RBTP gradients developed in a reproducible pattern: RT > LF = LT > RF > MB > CB. These gradients appeared early, widened as the volume of the mass increased, and persisted for the entire duration of the experiment. The study indicates that RBTP gradients develop in the presence of an extradural temporal mass lesion. The highest RBTP was recorded in the ipsilateral temporal lobe, whereas the next highest was recorded in the contralateral frontal lobe. The RBTP that was measured in either frontal lobe underestimated the temporal RBTP. These results indicated that if a frontal intraparenchymal pressure monitor is used in a patient with temporal lobe pathology, the monitor should be placed on the contralateral side and a lower threshold for therapy of increased intracranial pressure should be adopted. Furthermore, this study provides further evidence that reliance on a single frontal intraparenchymal pressure monitor may not detect all areas of elevated RBTP.

Brain tissue pressure gradients created by expanding frontal epidural mass lesion.

A porcine model was used to study the regional intracranial pressure (ICP) differences caused by a frontal mass lesion. Intraparenchymal ICP monitors were placed in the right and left frontal lobes, right and left temporal lobes, midbrain, and cerebellum. A frontal epidural mass lesion was created by placing a balloon catheter through a burr hole into the right frontal epidural space. A computer was used to acquire data from all monitors at 50-msec intervals. The balloon was expanded by 1 cc over a period of 1 second every 5 minutes and maximum pressure immediately before and during expansion was determined for each balloon volume at each site. Prior to expansion of the mass, the morphology of the cerebellum pressure tracing was different from that seen in all supratentorial regions. Also, pressures in the midbrain, at baseline, were slightly but significantly lower than pressures in the frontal and temporal regions. During expansion of the mass, a pressure differential that increased as the size of the mass increased developed between intracranial regions. Furthermore, the regional pressures were found to vary in a consistent fashion expressed by the formula RF=LF>RT=LT>MB>CB, in which RF and LF are the right and left frontal lobes, RT and LT are the right and left temporal lobes, MR in the midbrain, and CB is the cerebellum. The study shows that an expanding epidural mass reproducibly results in a gradient of brain parenchymal pressure. This gradient results in parenchymal pressures that are significantly different in each region of the brain depending on the proximity of that region to the epidural mass. The results of this study have implications for clinical ICP monitoring and therapy.

Sarcoid myelopathy.

A 45-year-old woman with history of iritis, uveitis, and sarcoidosis of the skin presented with a subacute cervical myelopathy. Magnetic resonance imaging (MRI) showed patchy, multifocal, gadolinium-enhancing intramedullary lesions of the spinal cord, and extramedullary lesions of the basal cisterns and fourth ventricle. Symptoms and MRI abnormalities were improved within 1 month of corticosteroid therapy.

Advanced trauma life support: assessment of cognitive achievement.

One hundred fifteen physicians participating in advanced trauma life support (ATLS) training courses had entry (pre-test) and exit (post-test) level knowledge compared. There was significant improvement for the overall group mean score from the pre-test to post-test (p = 0.0001). Comparisons revealed significant differences for pre-test and post-test scores by practice specialty and level of training. Residents in training had significantly higher scores for both pre-test (p = 0.0177) and post-test (p = 0.0024) than did the practicing physician group. No significant differences were detected in the cognitive achievement between the residents according to practice specialty.

Structure of cis-1-([4-(1-imidazolylmethyl)cyclohexyl]methyl)imidazole- succinic acid complex.

CGS 14796C, C14H20N4.C4H6O4, Mr = 362.43, monoclinic, C2/c, a = 28.148 (4), b = 9.722 (1), c = 19.200 (2) A, beta = 133.06 (1) degree, V = 3838.88 A3, Z = 8, Dx = 1.26 Mg m-3, lambda (Cu K alpha) = 1.5418 A, mu 0.702 mm-1, F(000) = 1552, T = 294 K, R = 0.075 for all 3285 reflections. The structure is composed of linear chains of alternating CGS 14796C and succinic acid molecules. The CGS 14796C molecule is in an extended conformation.

Structure-activity studies of non-steroidal aromatase inhibitors: the crystal and molecular structures of CGS 16949A and CGS 18320B.

The crystal and molecular structures of 4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)benzonitrile hydrochloride (CGS 16949A) and bis(p-cyanophenyl)imidazo-1-yl methane hemisuccinate (CGS 18320B) have been determined as part of structure-activity relationship studies of non-steroidal aromatase inhibitors. CGS 18320B crystallizes with two inhibitor molecules in the asymmetric unit that are similar in conformation. The cyanophenyl groups and the imidazole moieties in the CGS 18320B molecules display a propellor-like arrangement. The orientation of the imidazole ring in CGS 16949A, which is constrained by the piperidine ring, differs by about 80 degrees from the orientations in both CGS 18320B molecules. The conformations of both compounds are consistent with the proposed model (Banting et al. (1988) J. Enz. Inhibit., 2, 216) for inhibitor binding by positioning of the cyanophenyl group in the steroid A-ring binding site and interaction of the imidazole nitrogen with the iron of the haem.