Tension-band wiring of olecranon fractures - Biomechanical analysis of different fixation techniques

Tension-band wiring is a recognised standard treatment for fixation of olecranon fractures. The classical operation technique is well known and widespread among the orthopaedic surgeons. Nevertheless complications like K-wire migration or skin perforation and difficult technical as well as anatomical prerequisites require better-adapted operation fixation methods. In older female patients a cut through of the Kirschner wires with concomitant secondary displacement was observed. We intent to develop a new, better adapted operation technique for olecranon fractures in the old patients, in order to decrease complications and follow-up procedures. In this study we compare two different K-wire positions: 10 models of the classical AO tension-banding to 10 models with adapted K-wire insertion. In this group the K-wire passes from the tip of the olecranon to the posterior cortical of the distal fragment of the ulna. We tested maximal failure load, maximal opening angle as well as maximal work to achieve maximal force. In either technique we were able to determine different variables: a maximal failure load of more than 600N (p = 0.94) for both fixation methods and a maximal opening angle for both techniques of about 10° (p = 0.86). To achieve the maximal force our modified technique required a slightly increased work (p = 0.16). In this study no statistical significant differences between the two fixation techniques was shown. This leads to the conclusion that the modified version is comparable to the classical operation technique considering the stability, but due to the adaption of the angle in the modified procedure, less lesions of neurovascular structures on the volar side can be expected. To support our findings cadaver studies are needed for further investigations

The effect of employment and workers\u27 compensation litigation on the pain, psychological state and disability of chronic back pain sufferers

Previous research exploring the relationship between litigation status and the symptoms of the plaintiff has been inconsistent and limited by methodological dlfficulties. While Mendelson (1984, 1986, 1988) argued there was no difference In symptoms and rates of work return between litigating chronic pain patients and those not involved in the compensation system, others argued that work related injuries were maintained either by the plaintiffs\u27 wish for monetary compensation (compensation neurosis), or by their involvement in the medico-legal process with the stress of the litigation slowing down the recuperative process (nomogenic influences). Dworkin and colleagues (1985) highlighted the importance of including employment status as a variable of effect by arguing the inconsistencies in the literature on the effects of litigation may be explained by the variability among studies in the percentages of patients who were receiving compensation (or who had litigation pending) who were also working. The present longitudinal study addressed many of the methodological short comings of previous research and examined the relationship between litigation status, employment, psychological distress, pain and disability over the duration of the compensation process. 200 chronic back pain participants were selected from patients who, between March 1991 and November 1993, attended an initial assessment interview at the Perth Pain Management Centre (PPMC) a multidisciplinary pain centre. According to their litigation and employment status these patients were divided into four groups (n=5O), namely a non-litigation non-working group (NLnw), a non- working group (NLw), a litigating non-working group (Lnw) and a litigating working group(Lw). All participants completed three questionnaire, one at intake, one a minimum of 2 years later (for litigants during the litigation process) with the final questionnaire completed a minimum of 15 months thereafter (for litigants after they had settled their claim). Questionnaires contained measures of pain (Visual Analogue Scale, Short Form McGill Pain Questionnaire), depression (Zung Self-Rating Depression Scale), anxiety (Modified Somatic Perception Questionnaire) and disability (Oswestry Disability Questionnaire). Overall participants who were working scored lower on all the measures than did participants who were not working. On the other hand participants who were litigating scored higher on all the measures then did participants who were not litigating. There was a significant time effect on all measures but this was qualified on some measures by the Interaction of Time with Litigation status (VAS, Zung, Oswestry) and Time with Work status (Zung). The present research further demonstrated that both litigation and employment were significant factors influencing recovery from injury. Implications of these findings are discussed including the view that efforts should be directed towards minimising nomogenic factors while maximising the chances of returning injured workers to their workplace, even if this is in an alternative, reduced capacity

The causes of Charcot-Marie-Tooth disease

Charcot-Marie-Tooth (CMT) disease serves as the summary term for the most frequent forms of inherited peripheral neuropathies that affect motor and sensory nerves. In the last 12 years, 14 genes have been identified that cause different CMT subforms. The genes found initially are predominantly responsible for demyelinating and dysmyelinating neuropathies. Genes affected in axonal and rare forms of CMT have only recently been identified. In this review, we will focus on the currently known genes that are associated with CMT syndromes with regards to their genetics and functio

The causes of Charcot-Marie-Tooth disease

ISSN:1420-682XISSN:1420-907

NMR quantum simulation of localization effects induced by decoherence

The loss of coherence in quantum mechanical superposition states limits the time for which quantum information remains useful. Similarly, it limits the distance over which quantum information can be transmitted, resembling Anderson localization, where disorder causes quantum mechanical states to become localized. Here, we investigate in a nuclear spin-based quantum simulator, the localization of the size of spin clusters that are generated by a Hamiltonian driving the transmission of information, while a variable-strength perturbation counteracts the spreading. We find that the system reaches a dynamic equilibrium size, which decreases with the square of the perturbation strength.Comment: 5 pages, 5 figure

Experimental implementation of encoded logical qubit operations in a perfect quantum error correcting code

Large-scale universal quantum computing requires the implementation of quantum error correction (QEC). While the implementation of QEC has already been demonstrated for quantum memories, reliable quantum computing requires also the application of nontrivial logical gate operations to the encoded qubits. Here, we present examples of such operations by implementing, in addition to the identity operation, the NOT and the Hadamard gate to a logical qubit encoded in a five qubit system that allows correction of arbitrary single qubit errors. We perform quantum process tomography of the encoded gate operations, demonstrate the successful correction of all possible single qubit errors and measure the fidelity of the encoded logical gate operations

A review of IATTC research on the early life history and reproductive biology of scombrids conducted at the Achotines Laboratory from 1985 to 2005

English: For nearly a century, fisheries scientists have studied marine fish stocks in an effort to understand how the abundances of fish populations are determined. During the early lives of marine fishes, survival is variable, and the numbers of individuals surviving to transitional stages or recruitment are difficult to predict. The egg, larval, and juvenile stages of marine fishes are characterized by high rates of mortality and growth. Most marine fishes, particularly pelagic species, are highly fecund, produce small eggs and larvae, and feed and grow in complex aquatic ecosystems. The identification of environmental or biological factors that are most important in controlling survival during the early life stages of marine fishes is a potentially powerful tool in stock assessment. Because vital rates (mortality and growth) during the early life stages of marine fishes are high and variable, small changes in those rates can have profound effects on the properties of survivors and recruitment potential (Houde 1989). Understanding and predicting the factors that most strongly influence pre-recruit survival are key goals of fisheries research programs. Spanish: Desde hace casi un siglo, los científicos pesqueros han estudiado las poblaciones de peces marinos en un intento por entender cómo se determina la abundancia de las mismas. Durante la vida temprana de los peces marinos, la supervivencia es variable, y el número de individuos que sobrevive hasta las etapas transicionales o el reclutamiento es difícil de predecir. Las etapas de huevo, larval, y juvenil de los peces marinos son caracterizadas por tasas altas de mortalidad y crecimiento. La mayoría de los peces marinos, particularmente las especies pelágicas, son muy fecundos, producen huevos y larvas pequeños, y se alimentan y crecen en ecosistemas acuáticos complejos. La identificación los factores ambientales o biológicos más importantes en el control de la supervivencia durante las etapas tempranas de vida de los peces marinos es una herramienta potencialmente potente en la evaluación de las poblaciones. Ya que las tasas vitales (mortalidad y crecimiento) durante las etapas tempranas de vida de los peces marinos son altas y variables, cambios pequeños en esas tasas pueden ejercer efectos importantes sobre las propiedades de los supervivientes y el potencial de reclutamiento (Houde 1989). Comprender y predecir los factores que más afectan la supervivencia antes del reclutamiento son objetivos clave de los programas de investigación pesquera

An integrated chemical and stable-isotope model of the origin of Midocean Ridge Hot Spring Systems

Chemical and isotopic changes accompanying seawater-basalt interaction in axial midocean ridge hydrothermal systems are modeled with the aid of chemical equilibria and mass transfer computer programs, incorporating provision for addition and subtraction of a wide-range of reactant and product minerals, as well as cation and oxygen and hydrogen isotopic exchange equilibria. The models involve stepwise introduction of fresh basalt into progressively modified seawater at discrete temperature intervals from 100° to 350°C, with an overall water-rock ratio of about 0.5 being constrained by an assumed δ^(18)O_(H_2O) at 350°C of +2.0 per mil (H. Craig, personal communication, 1984). This is a realistic model because: (1) the grade of hydrothermal metamorphism increases sharply downward in the oceanic crust; (2) the water-rock ratio is high (>50) at low temperatures and low (<0.5) at high temperatures; and (3) it allows for back-reaction of earlier-formed minerals during the course of reaction progress. The results closely match the major-element chemistry (Von Damm et al., 1985) and isotopic compositions (Craig et al., 1980) of the hydrothermal solutions presently emanating from vents at 21°N on the East Pacific Rise. The calculated solution chemistry, for example, correctly predicts complete loss of Mg and SO_4 and substantial increases in Si and Fe; however, discrepancies exist in the predicted pH (5.5 versus 3.5 measured) and state of saturation of the solution with respect to greenschist-facies minerals. The calculated δD_(H_2O) is +2.6 per mil, in excellent agreement with analytical determinations. The calculated chemical, mineralogic, and isotopic changes in the rocks are also in good accord with observations on altered basalts dredged from midocean ridges (Humphris and Thompson, 1978; Stakes and O'Neil, 1982), as well as with data from ophiolites (Gregory and Taylor, 1981). Predicted alteration products include anhydrite and clay minerals at low temperatures and a typical albite-epidote-chlorite-tremolite (greenschist) assemblage at 350°C. The models demand that the major portion of the water-rock interaction occur at temperatures of 300°–350°C. Interaction at temperatures below approximately 250°C results in negative δ^(18)_O_(H_2O) shifts, contrary to the observed positive δ^(18)O values of the fluids exiting at midocean ridge vents. Hydrogen isotope fractionation curves by Suzuoki and Epstein (1976), Lambert and Epstein (1980), and Liu and Epstein (1984), among others, are compatible with the model, and require δD_(H_2O) to increase at all temperatures as a result of seawater-basalt interaction

Cosmic ray records in Antarctic meteorites

The cosmogenic radionuclides Be(10), Al(26), and Mn(53) and noble gases were determined in more than 28 meteorites from Antarctica by nuclear analytical techniques and static mass spectrometry, respectively. The summarized results are listed. The concentrations of Al(26) and Mn(53) are normalized to the repective main target elements and given in dpm/kg Si sub eq and dpm/kg Fe. The errors stated include statistical as well as systematical errors. For noble gas concentrations estimated errors are 5% and for isotopic ratios 1.5%. Cosmic ray exposure ages T sub 21 were calculated by the noble gas concentrations and the terrestrial residence time (T) on the basis of the spallogenic nuclide Al(26). The suggested pairing of the LL6 chondrite RKPA 80238 and RKPA 80248 and the eucrites ALHA 76005 and ALHA 79017 is confirmed not only by the noble gas data but also by the concentrations of the spallation produced radionuclides. Futhermore, ALHA 80122, clasified as an H6 chondrite, has a noble gas pattern which suggest that this meteorite belongs to the ALHA 80111 shower