NMR methods for studying the structure and dynamics of RNA

Proper functioning of RNAs requires the formation of complex three-dimensional structures combined with the ability to rapidly interconvert between multiple functional states. This review covers recent advances in isotope-labeling strategies and NMR experimental approaches that have promise for facilitating solution structure determinations and dynamics studies of biologically active RNAs. Improved methods for the production of isotopically labeled RNAs combined with new multidimensional heteronuclear NMR experiments make it possible to dramatically reduce spectral crowding and simplify resonance assignments for RNAs. Several novel applications of experiments that directly detect hydrogen-bonding interactions are discussed. These studies demonstrate how NMR spectroscopy can be used to distinguish between possible secondary structures and identify mechanisms of ligand binding in RNAs. A variety of recently developed methods for measuring base and sugar residual dipolar couplings are described. NMR residual dipolar coupling techniques provide valuable data for determining the long-range structure and orientation of helical regions in RNAs. A number of studies are also presented where residual dipolar coupling constraints are used to determine the global structure and dynamics of RNAs. NMR relaxation data can be used to probe the dynamics of macromolecules in solution. The power dependence of transverse rotating-frame relaxation rates was used here to study dynamics in the minimal hammerhead ribozyme. Improved methods for isotopically labeling RNAs combined with new types of structural data obtained from a growing repertoire of NMR experiments are facilitating structural and dynamic studies of larger RNAs.     

Laser surface refinement of YBa2Cu3O x superconductor

A novel laser-processing technique that produces bulk YBa₂Cu₃O _x (1 2 3) plates has been developed. Through the application of a square CO₂ laser beam with uniform energy density distribution to the surface of 1 2 3 powder compact, a single piece of ribbon-like plate is produced. This plate may be separated from the powder compact after laser scanning. The width of the plate is 6 mm, while its thickness is 0.1–0.2 mm. Powder X-ray diffraction indicates that laser-treated samples contain both orthorhombic and tetragonal 1 2 3 phases, as well as Y₂O₃ (2 0 0), Y₂BaCuO₅ (2 1 1), BaCuO₂ (0 1 1), and CuO (0 0 1) phases. Scanning electron microscopy reveals a pattern of phase segregation along the transverse cross-section after solidification of the plate. After oxygen annealing of a single ribbon piece, T _c is found to be 90 K. This technique may be applicable to the mass production of 1 2 3 bulk superconductor by continuous melting of 1 2 3 powders. In addition to its potential for practical applications, the laser technique also helps to explain the complex phases and microstructure formation during melting and solidification of laser-melted 1 2 3 liquid. A model relating the microstructure to the thermal history inside the laser-affected region and to the phase diagram of incongruently melting 1 2 3 material has been developed to analyse phase formation during laser melting and solidification processes. Reasonable correspondence between theoretical analysis and experimental results was obtained.     

Esophagoprotective potential of cisapride. An additional benefit for gastroesophageal reflux disease

BACKGROUND: Synchronous bilateral breast carcinoma (SBBC) is an uncommon presentation, and the management of patients with this disease is not well established. METHODS: In order to evaluate whether patients with early-stage SBBC could be safely and effectively treated with bilateral breast-conserving therapy (BCT), the authors retrospectively reviewed the records of 24 patients with clinical Stage I-II SBBC treated during the period 1977-1989 with bilateral BCT. SBBC was defined as bilateral invasive carcinomas diagnosed no more than 1 month apart. The median age at diagnosis was 56 years (range, 32-85 years), and the median follow-up for surviving patients was 95 months (range, 68-157 months). Pathology slides were available for review in 19 cases. Cosmetic results and complications after BCT were scored. Outcome was compared with that of 1314 patients with unilateral Stage I or II breast carcinoma, within the same age range, treated during the same time period. RESULTS: There were no significant differences between the SBBC and unilateral groups in actuarial disease free survival (70% and 74%, respectively, at 5 years), overall survival (88% and 87%, respectively, at 5 years), or crude distribution of sites of first failure. Multivariate analysis of overall survival and disease free survival also did not show bilaterality to be a significant factor. The cosmetic results for the SBBC group were not significantly different from those for the unilateral group. Physician assessment of cosmetic outcome was excellent in 57% and good in 43% of SBBC patients evaluated 25-48 months after BCT. Long term complications were rare in both groups. CONCLUSIONS: Patients with early-stage SBBC can be safely treated with carefully planned, bilateral BCT, with outcome that appears to be comparable to that of patients with early-stage unilateral breast carcinoma.     

Dormancy in Malting Barley: Quantifying the Effect of Storage Temperature on Different Varieties and the Response to Sudden Cooling

The rates of break of dormancy of the varieties Blenheim and Pipkin were examined during storage at temperatures of 8, 18, 26 and 33°C. The results were fitted to an established probit model of dormancy and compared with the previously fitted equations for Triumph. Triumph was shown to be the variety with the slowest recovery rate and this was consistent with the observations of other researchers. A similarity between varieties in the change of recovery rate with temperature suggested a consistency in the controlling reaction. A second experiment examined whether the sudden cooling of warm barley could induce ‘secondary dormancy’. The variety Triumph was stored at 12% moisture content and 33°C. Samples were then transferred to 8 or 15°C at different times. This procedure did not bring about any significant reduction in germinative energy. The only effect of a sudden temperature drop was a reduction in the rate of emergence from dormancy. ‘Secondary dormancy’ was not induced. The work is introduced and the results discussed in the context of the development of a thermally based integrated control strategy for malting barley. The strategy was designed to minimise the use of chemicals.     

The alliance as mediator of expectancy effects in short-term individual therapy.

The authors investigated the hypothesis that the therapeutic alliance mediates the relationship between pretherapy expectancy of improvement and psychotherapy outcome. Data were drawn from a comparative trial of 2 forms of short-term, time-limited individual psychotherapy (W. E. Piper, A. S. Joyce. M. McCallum, & H. F. Azim, 1998). Measures of expectancy and outcome were based on an individualized assessment of target objectives; outcome was considered from 3 perspectives (patient, independent assessor, therapist). Using the R. M. Baron and D. A. Kenny (1986) procedure, the authors, found evidence in support of the hypothesized mediation effect. The effect was evident when the alliance was rated from the perspective of either patient or therapist, and it accounted for one third of the direct impact of expectancy on outcome. Clinical implications and limitations of the study are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On-mask CD and overlay test structures for alternating aperture phase shift lithography

Atomic force and scanning electron microscope measurements of electrical structures for the measurement of critical dimension on alternating aperture phase shifting masks are presented. These have been used to explain anomalies that were observed in previously reported work. In addition, the development of a new capacitance test structure which can measure the alignment between the chrome blocking layer and the phase shifting areas etched into the quartz mask substrate is presented. A progressional offset array technique enables the use of this test structure without calibration and this is demonstrated by simulation and measurements.     

Personality disorders and response to group-oriented evening treatment.

The treatment of patients with personality disorders remains a challenging endeavor. The influence of paranoid, borderline, and dependent personality disorders on 154 patients' responses to an intensive group-oriented evening treatment program was investigated. Possible mediating effects of patient psychological mindedness and work were also investigated. Postsessional work ratings were provided by patients, therapists, and other patients for a small insight-oriented group. Benefit was assessed by using general impressions of overall usefulness, provided by patients and therapists. Results indicated that psychological mindedness had a differential influence on work and outcome for the 3 disorders, but work was related to outcome regardless of the disorders. Implications and limitations of the study are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding process-induced microstructures in RBa2Cu3O7

During the processing of rare earth (R)-barium-copper-oxygen superconductors, a variety of microstructures can be induced. Many processes are designed to avoid forming some structures, but these same processes can result in other structures which degrade the superconducting properties. Because liquid phases can be detrimental, for example, low-temperature calcination is often employed. But the CO₂ gas evolved during calcination leads to the formation of a nanoc-rystalline microstructure which may affect superconducting properties. Textures and defects can be induced by high-temperature and high-pressure deformation. For commercial dreams to become reality, these processing-induced microstructures, and their effects on properties, will have to be understood and controlled.     

The influence of between-needle cannulation distance on the efficacy of hemodialysis treatments

There is a belief that there should be a minimum of 5 cm between two cannulating needles of an arteriovenous fistula. This study examined the effect of reduction of space between needles from 5 cm to 2.5 cm on access recirculation, the measurement of access blood flow rate (by indicator dilution technology), and dialysis efficiency (by effective ionic dialysance). Twelve patients were studied, with half having their dialysis needles placed 2.5 cm apart for five consecutive dialysis treatments followed by placing needles 5 cm apart for a further five consecutive treatments. The other half initiated with 5 cm followed by 2.5 cm distance for a similar number of treatments. All 120 dialyses had successful cannulations with access recirculation excluded. Access blood flow (Qa mL/min) measurement was attempted for each patient twice, with each of the two needle positions. The Qa with needles 2.5 cm apart was 1310.95 ± 525.7 mL/min (M ± SD, n = 21) and was 1001.0 ± 240.4 mL/min when 5 cm apart (n = 22) (p = 0.014). There was a correlation between these two sets of Qa values (r = 0.554; p = 0.011). The effective ionic dialysance values obtained with needles 2.5 cm or 5 cm apart were similar and correlated strongly (r = 0.71; p = 0.000). Hemodialysis treatments using arteriovenous fistulae and two needles as close as 2.5 cm apart are possible without access recirculation and impairment of clearance. Indicator dilution access blood flow measurements are not recommended under these circumstances.     

Prospects for Non-Rare Earth Permanent Magnets for Traction Motors and Generators

With the advent of high-flux density permanent magnets based on rare earth elements such as neodymium (Nd) in the 1980s, permanent magnet-based electric machines had a clear performance and cost advantage over induction machines when weight and size were factors such as in hybrid electric vehicles and wind turbines. However, the advantages of the permanent magnet-based electric machines may be overshadowed by supply constraints and high prices of their key constituents, rare earth elements, which have seen nearly a 10-fold increase in price in the last 5?years and the imposition of export limits by the major producing country, China, since 2010. We outline the challenges, prospects, and pitfalls for several potential alloys that could replace Nd-based permanent magnets with more abundant and less strategically important elements.