Influence of preoperative factors on timing for bilateral shoulder arthroplasty.

INTRODUCTION: In bilateral shoulder arthroplasty patients, it is unclear what features are responsible for the timing of their contralateral shoulder arthroplasty. This study hypothesized that patient factors (age, gender, and hand dominance), disease factors (diagnosis and radiographic severity of contralateral shoulder), and surgical factors (type of arthroplasty) impact the timing to contralateral surgery. METHODS: A retrospective review of 332 patients treated with bilateral anatomic (TSA) or reverse (RSA) shoulder arthroplasty (172 TSA/TSA, 107 RSA/RSA, or 53 TSA/RSA) were divided into groups depending on the interval timing between arthroplasty surgeries: group 1, n = 142 (≤1 year); group 2, n = 62 (1-2 years); and group 3, n = 128 (≥2 years). Preoperative factors were analyzed to determine associations between different time groups, including age, gender, hand dominance, diagnosis, radiographic severity of contralateral shoulder, and type of surgery. Bilateral diagnoses included 211 osteoarthritis (OA), 36 cuff tear arthropathy (CTA), 13 inflammatory arthritis, 12 massive cuff tears without OA, and 4 avascular necrosis. RESULTS: OA patients had their contralateral shoulder arthroplasty sooner than CTA patients (P = .035). OA patients with arthritic changes on contralateral radiographs before the first arthroplasty had their contralateral arthroplasty sooner than those without contralateral radiographs (P < .0001). Patients who had TSA first had their contralateral arthroplasty sooner than patients who had RSA first (P = .037). DISCUSSION: This study confirmed our hypothesis identifying preoperative variables associated with different time intervals between arthroplasties. The preoperative factors associated with the highest likelihood of having contralateral shoulder arthroplasty within 1 year included OA, radiographic bilateral shoulder disease, and TSA for the first surgery.

Atomic-scale description of interfaces in rutile/sodium silicate glass-crystal composites.

In this work interfaces between (Na2O)x(SiO2)1-x glasses (for x = 0.0, 0.1 and 0.2) and TiO2 crystals are simulated using molecular dynamics and empirical potentials. Interfaces are presented for the distinct terminating surfaces of TiO2 with Miller indices ≤2, the properties of which have been investigated using atomistic models. Simulations showed that partially ordered layers had been induced in the glass close to the interfaces, with successive oxygen-rich and cation-rich planes being noted. The first silicate layer in contact with the crystal tended to be highly-structured, with Si ions occupying well-defined positions that depend on the orientation of the crystal at the interface, and showing 2-dimensional ordering depending on glass composition. Finally, interface energies were calculated. These indicated that the interface formation may stabilise a crystal surface in comparison to maintaining a free surface. Results are presented suggesting that the structural flexibility of the glass network allows it to conform to the crystal, thereby providing charge compensation and avoiding large relaxation of the crystal structure close to the interfaces. Such interfacial properties could be crucial to improving phenomenological models of glass-crystal composite properties.

Crystal Structures of Al-Nd Codoped Zirconolite Derived from Glass Matrix and Powder Sintering.

Zirconolite is a candidate host for immobilizing long-lived radionuclides. Zirconolite-based glass-ceramics in the CaO-SiO2-Al2O3-TiO2-ZrO2-Nd2O3-Na2O matrix are a potential waste form for immobilizing actinide radionuclides and can offer double barriers to immobilize radioactive elements. However, the X-ray diffraction patterns of the zirconolite derived from the glass matrix (glass ceramic, GC) are significantly different from those prepared by powder sintering (PS). In this Article, the crystal structures of Al-Nd codoped zirconolite grown via the glass matrix route and the powder sintering route are investigated in detail. Two samples of Al-Nd codoped zirconolite were prepared: one was grown from a CaO-SiO2-Al2O3-TiO2-ZrO2-Nd2O3-Na2O glass matrix, and the other was prepared with a Ca0.75Nd0.25ZrTi1.75Al0.25O7 composition by powder sintering. The samples were then characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX), and selected area electron diffraction (SAED). The chemical composition of the 100-500 nm zirconolite crystals grown from a glass matrix was determined by TEM-EDX to be Ca0.83Nd0.25Zr0.85Ti1.95Al0.11O7. PXRD and SAED results showed that these two Al-Nd codoped zirconolite phases were crystallized in space group C12/c1. The HRTEM images and SAED results showed that there were heavy stacking faults in the zirconolite crystals grown from the glass matrix. In contrast, far fewer defects were found in the zirconolite crystals prepared by powder sintering. The split-atom model was adopted for the first time to construct the Al-Nd codoped zirconolite structure grown from glass during the Rietveld refinement. The isostructural method assisted by Rietveld refinement was used to resolve the Al-Nd codoped zirconolite structures prepared by different methods. The occupancies of the cation sites were identified, and the distribution behavior of Nd(3+) was further investigated. The results indicate that the heavy stacking faults may lead to substantial differences in the Al-Nd codoped zirconolite structures prepared by these two fabrication routes.

Depression- and anxiety-related sick leave and the risk of permanent disability and mortality in the working population in Germany: a cohort study.

BACKGROUND: Anxiety and depression are the most common psychiatric disorders and are the cause of a large and increasing amount of sick-leave in most developed countries. They are also implicated as an increasing mortality risk in community surveys. In this study we addressed, whether sick leave due to anxiety, depression or comorbid anxiety and depression was associated with increased risk of retirement due to permanent disability and increased mortality in a cohort of German workers. METHODS: 128,001 German workers with statutory health insurance were followed for a mean of 6.4 years. We examined the associations between 1) depression/anxiety-related sick leave managed on an outpatient basis and 2) anxiety/depression-related psychiatric inpatient treatment, and later permanent disability/mortality using Cox proportional hazard regression models (stratified by sex and disorder) adjusted for age, education and job code classification. RESULTS: Outpatient-managed depression/anxiety-related sick leave was significantly associated with higher permanent disability (hazard ratio (95% confidence interval)) 1.48 (1.30, 1.69) for depression, 1.25 (1.07, 1.45) for anxiety, 1.91 (1.56, 2.35) for both). Among outpatients, comorbidly ill men (2.59 (1.97,3.41)) were more likely to retire early than women (1.42 (1.04,1.93)). Retirement rates were higher for depressive and comorbidly ill patients who needed inpatient treatment (depression 3.13 (2,51, 3,92), both 3.54 (2.80, 4.48)). Inpatient-treated depression was also associated with elevated mortality (2.50 (1.80, 3.48)). Anxiety (0.53 (0.38, 0.73)) and female outpatients with depression (0.61 (0.38, 0.97)) had reduced mortality compared to controls. CONCLUSIONS: Depression/anxiety diagnoses increase the risk of early retirement; comorbidity and severity further increase that risk, depression more strikingly than anxiety. Sickness-absence diagnoses of anxiety/depression identified a population at high risk of retiring early due to ill health, suggesting a target group for the development of interventions.

Prevalence and childhood antecedents of depersonalization syndrome in a UK birth cohort.

PURPOSE: Depersonalization syndrome is characterised by a sense of unreality about the self [depersonalization (DP)] and/or the outside world [derealization (DR)]. Prevalence estimates vary widely. Little is known about childhood antecedents of the disorder although emotional abuse is thought to play a role. METHODS: Longitudinal data from 3,275 participants of a UK population-based birth cohort (the MRC National Survey of Health and Development) were used to: (1) assess the prevalence of DP syndrome at age 36, measured by the Present State Examination (PSE); and (2) examine the effects of a range of socio-demographic, childhood adversity and emotional responses as potential risk factors for DP. RESULTS: Thirty three survey members were classified with DP, yielding a prevalence of 0.95% [95% confidence intervals (CI) 0.56-1.34]. There were no associations with socio-economic status, parental death or divorce; self-reported accidents, childhood depression, tendency to daydream or reactions to criticism. However, teacher-estimated childhood anxiety was a strong independent predictor of adult depersonalization, and there were strong cross-sectional relationships between DP and anxiety and depression caseness. CONCLUSIONS: To our knowledge this is the first study assessing nationwide prevalence of the DP syndrome and uses longitudinal data to explore childhood risk factors for adult DP. The prevalence of adult DP was slightly lower than reported by other surveys. The study found that childhood anxiety was the only significant predictor of the adult DP syndrome, supporting the view that depersonalisation disorder forms part of the spectrum of responses to anxiety.

The quality of the evidence for dietary advice given in UK national newspapers.

INTRODUCTION: Newspaper reports advocating dietary intake changes may impact on dietary choice and food related health beliefs. The scientific basis and quality of evidence underpinning these reports is uncertain. OBJECTIVE: To evaluate the scientific quality of newspaper reporting related to dietary advice. DESIGN: Articles offering dietary advice from the top ten selling UK newspapers for a randomly selected week were assessed using two established evidence grading scales: developed by the World Cancer Research Fund (WCRF) and the Scottish Intercollegiate Guidelines Network (SIGN). RESULTS: Of 111 dietary health claims identified, 72% and 68% (assessed by WCRF and SIGN criteria respectively) had levels of evidence lower than the convincing or probable categories that are recommended for dietary health claims. CONCLUSIONS: Misreporting of dietary advice by UK newspapers is widespread and may contribute to public misconceptions about food and health.

Skin dose in radiation treatment of the left breast: Analysis in the context of prone versus supine treatment technique.

PURPOSE: To determine how the skin dose varies in patients receiving radiation treatment for breast cancer in the prone and supine positions. METHODS: Fifty patients were scanned in the prone and supine positions. A radiation treatment plan was created for the left breast using a 6-MV beam for a prescribed dose of 42.66 Gy in 16 fractions. The dose was calculated using 1- and 2.5-mm calculation grid sizes and the surface dose was compared in both techniques. RESULTS: The median gantry angles relative to the skin surface at the central axis were 8 and 52 degrees for treatment in the prone and supine positions, respectively. The mean dose difference between the prone and supine techniques was statistically significant from 3- to 5-mm depth for both grid sizes. For the 1-mm calculation grid size, the doses at 3-, 4-, and 5-mm depths in the prone and supine techniques were 87.80% and 89.10% (P < 0.003), 91.92% and 94.50% (P < 0.00), and 95.30% and 98.20% (P < 0.00), respectively; for the 2.5-mm grid size, the respective doses were 87.10% and 88.59% (P < 0.00), 91.60% and 94.63% (P < 0.00), and 95.10% and 97.80% (P < 0.00), respectively. CONCLUSIONS: This study demonstrates that the prone technique facilitates a relatively lower skin dose than the supine technique. This observation is probably due to the beam angle. The beam is more perpendicular to the skin surface in the prone technique, whereas it is more tangential in the supine technique, which may deliver a higher skin dose. Thus, the dose to the skin should be evaluated in the prone technique, and if desired, the skin dose could be carefully augmented via a bolus or beam spoiler.

Deaths of cyclists in London: trends from 1992 to 2006.

BACKGROUND: Cycling is an increasingly important mode of transport for environmental and health reasons. Cycling fatalities in London were previously investigated in 1994 using routinely collected data. Since then, there have been shifts in the modes of transport used, and in transport policies. We sought to replicate the previous work using data on cyclist deaths in London between 1992 and 2006, specifically investigating whether heavy goods vehicles continued to pose a threat. METHODS: Observational study based on analysis of time series of police road casualties data, 1992 to 2006, in London, UK. The main outcome measures were cyclists killed in road traffic collisions. Poisson regression and chi-squared test for homogeneity were used to assess time effects. Travel flow data was then used to estimate annual fatality rates per 100,000 cyclists per kilometre. RESULTS: From 1992 to 2006 there was a mean of 16 cycling fatalities per year (range 8-21). 146 deaths (60%) were in inner London and 96 in outer London. There was no evidence for a decline over time (p = 0.7) other than a pronounced dip in 2004 when there were 8 fatalities. Freight vehicles were involved in 103 of 242 (43%) of all incidents and the vehicle was making a left turn in over half of these (53%). The fatality rate ranged from 20.5 deaths in 1992 to 11.1 deaths in 2006 per 100,000 estimated cyclists per kilometre (rate ratio 0.54, 95% confidence interval 0.28 to 1.03). CONCLUSIONS: There is little evidence fatality rates have fallen. Freight vehicles over 3.5 tonnes continue to present a disproportionate threat; they should be removed from urban roads and more appropriate means of delivery of essential goods found.

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures.

ZrC1-x (sub-stoichiometric zirconium carbide), a group IV transition metal carbide, is being considered for various high temperature applications. Departure from stoichiometry changes the thermo-physical response of the material. Reported thermo-physical properties exhibit, in some cases, a degree of scatter with one likely contributor to this being the uncertainty in the C/Zr ratio of the samples produced. Conventional, methods for assigning C/Zr to samples are determined either by nominal stochiometric ratios or combustion carbon analysis. In this study, a range of stoichiometries of hot-pressed ZrC1-x were examined by SEM, XRD, Raman spectroscopy and static 13C NMR spectroscopy and used as a basis to correct the C/Zr. Graphite, amorphous, and ZrC1-x carbon signatures are observed in the 13C NMR spectra of samples and are determined to vary in intensity with sintering temperature and stoichiometry. In this study a method is outlined to quantify the stoichiometry of ZrC1-x and free carbon phases, providing an improvement over the sole use and reliance of widely adopted bulk carbon combustion analysis. We report significantly lower C/Zr values determined by 13C NMR analysis compared with carbon analyser and nominal methods. Furthermore, the location of carbon disassociated from the ZrC1-x structure is analysed using SEM and Raman spectroscopy.

On the stoichiometry of zirconium carbide.

The dependencies of the enhanced thermomechanical properties of zirconium carbide (ZrCx) with sample purity and stoichiometry are still not understood due to discrepancies in the literature. Multiple researchers have recently reported a linear relation between the carbon to zirconium atomic ratio (C/Zr) and the lattice parameter, in contrast with a more established relationship that suggests that the lattice parameter value attains a maximum value at a C/Zr ~ 0.83. In this study, the relationship between C/Zr atomic ratio and the lattice parameter is critically assessed: it is found that recent studies reporting the thermophysical properties of ZrCx have unintentionally produced and characterised samples containing zirconium oxycarbide. To avoid such erroneous characterization of ZrCx thermophysical properties in the future, we propose a method for the accurate measurement of the stoichiometry of ZrCx using three independent experimental techniques, namely: elemental analysis, thermogravimetric analysis and nuclear magnetic resonance spectroscopy. Although a large scatter in the results (ΔC/Zr = 0.07) from these different techniques was found when used independently, when combining the techniques together consistent values of x in ZrCx were obtained.

Stoichiometry deviation in amorphous zirconium dioxide.

Amorphous zirconia (a-ZrO2) has been simulated using a synergistic combination of state-of-the-art methods: employing reverse Monte-Carlo, molecular dynamics and density functional theory together. This combination has enabled the complex chemistry of the amorphous system to be efficiently investigated. Notably, the a-ZrO2 system was observed to accommodate excess oxygen readily - through the formation of neutral peroxide (O2 2-) defects - a result that has implications not only in the a-ZrO2 system, but also in other systems employing network formers, intermediates and modifiers. The structure of the a-ZrO2 system was also determined to have edge-sharing characteristics similar to structures reported in the amorphous TeO2 system and other chalcogenide-containing glasses.

Biological Indices Evaluation of Various Treatment Techniques for Left-Sided Breast Treatment.

PURPOSE: To compare dose to organs at risk (OARs) and biological evaluation using normal tissue complication probability (NTCP) for left-sided breast radiation therapy in 4 techniques: supine free breathing (SFB), supine deep inspiration breath hold (SDIBH), prone free breathing (PFB), and prone deep inspiration breath hold (PDIBH). METHODS AND MATERIALS: Twenty-five patients with left-sided breast cancer suitable for this study underwent a computed tomography scan using SFB, SDIBH, PFB, and PDIBH. One radiation oncologist contoured the planning target volume and OAR (cardiac components). Dose-volume histograms and NTCPs for the heart, left ventricle (LV), left anterior descending artery (LAD), and left lung were calculated for all 4 techniques. RESULTS: The mean heart dose in PDIBH is 0.77 Gy, which is statistically significantly lower than in SFB (1.88 Gy, P < .0001), SDIBH (0.97 Gy, P < .001), and PFB (0.85 Gy, P < .001). The mean left lung dose is 0.69 Gy in PFB and 0.88 Gy in PDIBH. PFB and PDIBH have statistically significantly lower doses compared with SFB (6.09 Gy, P < .0001) and SDIBH (5.41 Gy, P < .0001). The mean NTCP in SFB for the heart, LV, and LAD is 0.27%, 0.62%, and 4.23%, respectively, and it is negligible for other techniques. CONCLUSIONS: We found that PDIBH had a dosimetrically lower mean dose for the heart and LV compared with the other 3 techniques. In addition, SDIBH, PFB and PDIBH had statistically significantly lower NTCP for the heart, LV, and LAD compared with SFB. NTCP for the left lung was statistically significantly lower for prone techniques compared with supine techniques. Therefore we concluded that, compared with SDIBH, PDIBH provides the added benefit of sparing the heart while keeping the benefit of sparing the lung as in the prone technique.

Evaluation of abduction range of motion and avoidance of inferior scapular impingement in a reverse shoulder model.

The purpose of this study was to determine the effects of prosthetic design and surgical technique of reverse shoulder implants on total abduction range of motion and impingement on the inferior scapular neck. Custom implants in three glenosphere diameters (30, 36, and 42 mm), with 3 different centers of rotation offsets (0, +5, and +10 mm), were placed into a Sawbones scapula (Pacific Research Laboratories, Vashon, WA) in 3 different positions: superior, center, and inferior glenoid. Humeral sockets were manufactured with a 130 degrees , 150 degrees , and 170 degrees neck-shaft angle. Four independent factors (glenosphere diameter, center of rotation offset, glenosphere position on the glenoid, and humeral neck-shaft angle) were compared with the 2 dependent factors of range of motion and inferior scapular impingement. Center of rotation offset had the largest effect on range of motion, followed by glenosphere position. Neck-shaft angle had the largest effect on inferior scapular impingement, followed by glenosphere position. This information may be useful to the surgeon when deciding on the appropriate reverse implant.

Biomechanical comparison of component position and hardware failure in the reverse shoulder prosthesis.

There has been renewed interest in reverse shoulder arthroplasty for the treatment of glenohumeral arthritis with concomitant rotator cuff deficiency. Failure of the prosthesis at the glenoid attachment site remains a concern. The purpose of this study was to examine glenoid component stability with regard to the angle of implantation. This investigation entailed a biomechanical analysis to evaluate forces and micromotion in glenoid components attached to 12 polyurethane blocks at -15 degrees, 0 degrees, and +15 degrees of superior and inferior tilt. The 15 degrees inferior tilt had the most uniform compressive forces and the least amount of tensile forces and micromotion when compared with the 0 degrees and 15 degrees superiorly tilted baseplate. Our results suggest that implantation with an inferior tilt will reduce the incidence of mechanical failure of the glenoid component in a reverse shoulder prosthesis.

Capillary electrophoresis laser-induced fluorescence for screening combinatorial peptide libraries in assays of botulinum neurotoxin A.

Botulinum neurotoxin serotype A (BoNT/A) is a proteolytic enzyme that induces muscle paralysis. It is a cause of food poisoning, a potential bioterrorist threat and, in low doses an emerging pharmaceutical product. No effective treatment is currently available for BoNT intoxication. Previously we developed a BoNT/A light chain enzyme assay using a peptide substrate based on the SNAP-25 protein target, with HPLC separation and UV detection of assay products, and applied the method to screen combinatorial peptide libraries for inhibitory activity to BoNT/A. We now report on development of a capillary electrophoresis laser-induced fluorescence (CE-LIF) method for measuring BoNT/A activity. The enzyme assay products were labeled with CBQCA dye followed by CE separation on a bare fused silica column in a HEPES-based buffer and LIF detection. All assay products were separated in CE within 8 min compared to incomplete separation of assay products within 1h by HPLC. The labeled products showed linear dependence of intensity versus concentration, and quantitative mole-fraction assignments. We used the CE-LIF method to screen combinatorial peptide libraries for potential modulating effects on BoNT/A peptidase activity. With some of the libraries, peptides co-migrated with assay products and interfered with quantitation. In such cases, interference was reduced by substituting sodium dodecyl sulfate (SDS) for Tween-20 in the running buffer. Separation in the capillaries then occurred by micellar electrokinetic chromatography (MEKC). The CE-LIF method is quick and lends itself to high-throughput or microfluidic formats.

Friction-reducing devices for lateral patient transfers: a clinical evaluation.

The purpose of this study was to assess the performance of lateral transfer devices compared with the traditional draw sheet method in acute care settings through subjective feedback of caregivers actually using the devices. Every 2 weeks, the eight participating acute care units each received one of the devices, which had been randomly selected. Data were collected through caregiver surveys, which rated comfort, ease of use, perceived injury risk, time efficiency, and patient safety. An overall performance rating was calculated as the sum of these five categories. Caregivers rated air-assisted devices significantly higher (p < .05) than other devices. Lateral transfer devices are recommended over the traditional draw sheet method for performing lateral patient transfers. These friction-reducing devices are a cost-effective solution to the load of lateral patient transfers and should be favorably considered when purchasing patient-handling technologies.

Synthesis and DFT investigation of new bismuth-containing MAX phases.

The Mn + 1AXn phases (M = early transition metal; A = group A element and X = C and N) are materials exhibiting many important metallic and ceramic properties. In the present study powder processing experiments and density functional theory calculations are employed in parallel to examine formation of Zr2(Al1-xBix)C (0 ≤ x ≤ 1). Here we show that Zr2(Al1-xBix)C, and particularly with x ≈ 0.58, can be formed from powders even though the end members Zr2BiC and Zr2AlC seemingly cannot. This represents a significant extension of the MAX phase family, as this is the first report of a bismuth-based MAX phase.

Synthesis and Characterization of an Alumina Forming Nanolaminated Boride: MoAlB.

The 'MAlB' phases are nanolaminated, ternary transition metal borides that consist of a transition metal boride sublattice interleaved by monolayers or bilayers of pure aluminum. However, their synthesis and properties remain largely unexplored. Herein, we synthesized dense, predominantly single-phase samples of one such compound, MoAlB, using a reactive hot pressing method. High-resolution scanning transmission electron microscopy confirmed the presence of two Al layers in between a Mo-B sublattice. Unique among the transition metal borides, MoAlB forms a dense, mostly amorphous, alumina scale when heated in air. Like other alumina formers, the oxidation kinetics follow a cubic time-dependence. At room temperature, its resistivity is low (0.36-0.49 µΩm) and - like a metal - drops linearly with decreasing temperatures. It is also a good thermal conductor (35 Wm(-1)K(-1) at 26 °C). In the 25-1300 °C temperature range, its thermal expansion coefficient is 9.5 × 10(-6 )K(-1). Preliminary results suggest the compound is stable to at least 1400 °C in inert atmospheres. Moderately low Vickers hardness values of 10.6 ± 0.3 GPa, compared to other transition metal borides, and ultimate compressive strengths up to 1940 ± 103 MPa were measured at room temperature. These results are encouraging and warrant further study of this compound for potential use at high temperatures.

Investigating the highest melting temperature materials: A laser melting study of the TaC-HfC system.

TaC, HfC and their solid solutions are promising candidate materials for thermal protection structures in hypersonic vehicles because of their very high melting temperatures (>4000 K) among other properties. The melting temperatures of slightly hypostoichiometric TaC, HfC and three solid solution compositions (Ta1-xHfxC, with x = 0.8, 0.5 and 0.2) have long been identified as the highest known. In the current research, they were reassessed, for the first time in the last fifty years, using a laser heating technique. They were found to melt in the range of 4041-4232 K, with HfC having the highest and TaC the lowest. Spectral radiance of the hot samples was measured in situ, showing that the optical emissivity of these compounds plays a fundamental role in their heat balance. Independently, the results show that the melting point for HfC0.98, (4232 ± 84) K, is the highest recorded for any compound studied until now.