Pulmonary function test outcomes in healthy Navajo Native American adolescents

Prediction equations for estimating lung volumes have been determined for Caucasians, African-Americans, and Mexican-Americans. These separate equations were determined because of differences in thoracic morphology between people of various racial groups, making it impossible to use one prediction formula to accurately estimate lung volumes for all individuals. One hundred ninety-one adolescent Navajo children (males, n = 110; females, n = 81) between 11 and 18 yr of age volunteered for the study and underwent a series of pulmonary function tests (PFT). New pulmonary function prediction equations for Navajo youth were generated for estimating pulmonary volumes and capacities that more accurately predict expected PFT outcomes than formulas in common use for Caucasian, Mexican-American, or African-American youth.     

Induced magnetic fields as evidence for subsurface oceans in Europa and Callisto

The Galileo spacecraft has been orbiting Jupiter since 7 December 1995, and encounters one of the four galilean satellites-Io, Europa, Ganymede and Callisto-on each orbit. Initial results from the spacecraft's magnetometer have indicated that neither Europa nor Callisto have an appreciable internal magnetic field, in contrast to Ganymede and possibly Io. Here we report perturbations of the external magnetic fields (associated with Jupiter's inner magnetosphere) in the vicinity of both Europa and Callisto. We interpret these perturbations as arising from induced magnetic fields, generated by the moons in response to the periodically varying plasma environment. Electromagnetic induction requires eddy currents to flow within the moons, and our calculations show that the most probable explanation is that there are layers of significant electrical conductivity just beneath the surfaces of both moons. We argue that these conducting layers may best be explained by the presence of salty liquid-water oceans, for which there is already indirect geological evidence in the case of Europa.     

The detection of oligonucleotide N3'-->P5' phosphoramidate/RNA duplexes with capillary gel electrophoresis

Oligonucleotide N3'-->P5' phosphoramidates (3'-phosphoramidates) are DNA analogs that are presently under investigation as potential therapeutic agents. These compounds may also hold promise as a diagnostic tool. Here, we describe a rapid method for the analysis of single-stranded RNA fragments utilizing 3'-phosphoramidate oligonucleotides as probes in conjunction with capillary gel electrophoresis (CGE). 3'-Phosphoramidate 9-mers were mixed with complimentary RNA, and CGE was used to monitor duplex formation. Complimentary strands of RNA and 3'-phosphoramidate formed duplexes that gave unique relative mobilities based on an internal standard. The ability of CGE to discriminate between perfect duplexes and duplexes that contain a base mismatch was also investigated. However, the primary focus of this work was to determine CGE's ability to detect the presence of the 3'-phosphoramidates/RNA duplex under routine electrophoretic running conditions. Polyacrylamide gel electrophoresis analysis was utilized to verify duplex formation.     

Controlling bacterial contamination of an enteral formula through the use of a unique closed system: contamination, enteral formulas, closed system

Contamination of enteral diets may play an essential role in formula tolerance and safety for patients. Contaminated enteral formula commonly support microbiological growth. Commercially sterile liquid formulas received from the manufacturer are required by the Food & Drug Administration (FDA) to be shelf-stable and free from enteric pathogens. This study examined the use of large volume, closed system containers in a typical nursing home. Large volume (1500 mL) containers with unique pierceable caps and piercing spikes were studied to determine their ability to reduce the incidence of microbiological contamination due to their design and ability to decrease handling requirements. This study took place in a room of a typical nursing home. In this clinical setting, 211 containers and administration spike sets were evaluated following a 36-h hangtime. Contamination was virtually nondetectable. Nursing staff in a clinical facility can effectively utilize a large volume, prefilled, ready-to-use feeding system to achieve delivery of noncontaminated product for up to 36 h hangtime.     

Homopolymer Nanolithography

Future progress in nanoscience and nanotechnology necessitates further development of versatile, labor‐, and cost‐efficient surface patterning strategies. A new approach to nanopatterning is reported, which utilizes surface segregation of a smooth layer of an end‐grafted homopolymer in a poor solvent. The variation in polymer grafting density yields a range of surface nanostructures, including randomly organized pinned spherical micelles, worm‐like structures, networks, and porous films. The capability to use the polymer patterns for site‐specific deposition of small molecules, polymers, or nanoparticles is shown. This versatile strategy enables patterning of curved surfaces with direct access to the substrate and no need in changing polymer composition to realize different surface patterns.     

Juvenile myoclonic epilepsy

CONCLUSION: We conclude that despite inevitable variability the clinical picture of JME is characteristic. It is easy to diagnose JME if one thinks of it while the history should be thoroughly analyzed. An EEG recording during sleep confirms the diagnosis. An early diagnosis of JME permits adequate prognosis of the subsequent course of epilepsy, and adequate therapy brings remission in most of the patients. If treatment starts following the large number of severe GTC seizures, the response to therapy is incomplete. The persistency of the illness throughout the life, the need for continuous medication and therapeutic unresponsiveness in cases with late diagnosis, do not justify the increasing misconception that JME is of benign nature. Diagnosis of JME is rare because of insufficient familiarily of physicians with the illness. BACKGROUND: Juvenile myoclonic epilepsy (JME) is an idiopathic generalized epileptic syndrome characterized with the combination of myoclonic, generalized tonic-clonic (GTC) and absence seizures that are readily provoked by sleep deprivation. PATIENTS: Forty-three patients, aged from 14 to 51 years, participated in a 5-year follow-up study. Diagnosis was made according to the criteria (Table 1) for diagnosis of JME set by Panayiotopoulos et al. (1994). Nineteen patients made their first contact with a neurologist at the Institute of Neurology and were diagnosed as JME, while the remaining 24 were referred to from other medical institutions with a diagnosis of therapy resistant to focal epilepsy. All patients underwent a somatic and neurological examination, "mini mental test," EEG in waking and CT scan of the brain. Some patients had EEG performed during sleep and some had MRI of the head. RESULTS: JME began between 9 and 26 (average 17) years. All patients had myoclonic seizures, 98% had GTC and 23% absence seizures. The first myoclonic seizure occurred between 9 and 24 years while the frst GTC seizure occurred between 10 and 32 years. Myoclonic seizures (83% of patients) and GTC seizures (70% of patients) occurred most often immediately after awaking. The most frequent provocative factors were insufficient sleep, alcohol abuse and tiredness. Epilepsy in the family was present in 39%, focal neurological deficiency in 9% and pathological findings on of CT and MRI in 7% of patients. Waking EEG was pathological in 77% of patients; it included generalized spike-wave discharges in 73%, multiple spike-wave complexes in 33% and focal discharges in 12% of patients, respectively. In all 26 patients tested, sleep EEG was pathological most often with multiple spike-wave complexes in 85% and 3-4 Hz spike-wave complexes in 57% of patients. The correct diagnosis of JME following a comprehensive examination was made in 24 (56%) patients after a delay of 1 to 35 years. In 24 patients with delayed diagnosis of JME the replacement of earlier medication with valproic acid (VPA) induced remission in 18 patients (75%) while 1 patient (4%) experienced a reduction in the number of seizures. Five patients (21%) did not respond to VPA medication: 2 due to a weak compliance, another 2 due to inefficient medication and 1 because of the preexistent malabsorption syndrome. In 19 patients (44%) with initial diagnosis of JME, VPA was introduced immediately upon diagnosis. Of them, 15 (79%) had excellent response to VPA, 1 refused therapy and for 3 patients there is no information. In 2 patients VPA was substituted due to side effects (hepatotoxicity and alopetia) with lamotrigine (low doses), which brought about decrease in frequency and mitigation in myoclonic seizures.     

Application of the scaling factor method to estimation of beta dose distributions for dissimilar media separated by a planar interface

Reliable methods of estimating doses are essential for the use of beta emitting radionuclides for radiotherapy. The passage of electrons through matter is a very complex phenomenon due to the large number of elastic and inelastic interactions resulting in scattering and energy losses. The analytical solution for the electron transport being intractable, the problem has been addressed by the Monte Carlo technique. Empirical or semiempirical less time consuming methods, such as the scaling factor method, may appear more preferable in practice when dealing with complicated source distributions. The method, proposed by Cross and co-workers [AECL Report Nos. AECL-1617 (1982), AECL 10521 (1992)] consists in the derivation of beta-ray dose distribution in other media from those in water by using a "scaling factor" or "relative attenuation factor" on distance and a closely related renormalization factor imposed by the energy conservation. This work investigates the accuracy of the scaling factor method using a statistical approach, a generalized chi 2 test, focusing on the particular case of potential interest, the scaling factor for water to bone. The direct comparison of the shapes of the depth dose deposition curves in the two media indicates discrepancies of less than 5% up to at least 60% of the range in bone, a depth within which 95% of the initial energy is deposited. The scaling factor derived by this method, 0.9720 +/- 0.0012, confirms the existing experimentally determined value of 0.973 +/- 1% [AECL Report No. AECL-10521 (1992)]. The accuracy of the determination is increased by almost a factor of 10. A way of improving the scaling method, especially for depth over the 60% continuous slowing down approximation range, by using a modulation function is also proposed.     

Components for the implementation of free-space optical crossbars

We describe an optical system developed to form the basis of a 64 × 64 free-space optical matrix-matrix crossbar switch. The design and performance of each of the main optical components is discussed: lenses, diffractive optical elements, and polarizing beamsplitters, together with the optomechanical hardware design. For these components, throughput levels of -6.9 dB have been achieved, which is compatible with full system operation at 10(-12) bit error rates at ≥270 Mbits s(-1).