Modelling and testing of a wave energy converter based on dielectric elastomer generators.

This paper introduces the analysis and design of a wave energy converter (WEC) that is equipped with a novel kind of electrostatic power take-off system, known as dielectric elastomer generator (DEG). We propose a modelling approach which relies on the combination of nonlinear potential-flow hydrodynamics and electro-hyperelastic theory. Such a model makes it possible to predict the system response in operational conditions, and thus it is employed to design and evaluate a DEG-based WEC that features an effective dynamic response. The model is validated through the design and test of a small-scale prototype, whose dynamics is tuned with waves at tank-scale using a set of scaling rules for the DEG dimensions introduced here in order to comply with Froude similarity laws. Wave-tank tests are conducted in regular and irregular waves with a functional DEG system that is controlled using a realistic prediction-free strategy. Remarkable average performance in realistically scaled sea states has been recorded during experiments, with peaks of power output of up to 3.8 W, corresponding to hundreds of kilowatts at full-scale. The obtained results demonstrated the concrete possibility of designing DEG-based WEC devices that are conceived for large-scale electrical energy production.

A biomechanical study of headless compression screws versus a locking plate in radial head fracture fixation.

HYPOTHESIS: Fixation of a 3-part radial head fracture with cannulated compression screws will show equivalent stiffness to a locking plate under axial load. Debate exists regarding the management of Mason type III fractures, with many believing that open reduction and internal fixation provides advantages over other options. By virtue of their subarticular placement, screw fixation is less likely to cause impingement compared with plate fixation, which can result in loss of rotation and requirement for hardware removal. Insufficient fixation stability can lead to nonunions, necrosis of the radial head, pain, and instability. We tested the mechanical stability of fixation of simulated radial head fractures using headless compression screws compared with standard plate construct. METHODS: Standardized test constructs were created with repeatable osteotomy cuts and hardware placement on each Synbone model (Synbone AG, Malans, Switzerland). We presectioned 22 proximal radius Synbone models to simulate a 3-part radial head fracture. The models were fixed using a radial head locking plate or headless compression screws in a tripod construct. The constructs were potted into a compression test jig using 2-part epoxy resin. Compression testing was performed using a 30-kN Instron Universal machine (Instron, Norwood, MA, USA). The compression tool was spherical, representing the surface of the capitellum. RESULTS: There was no significant difference between the stiffness of the Synbone constructs under axial load. CONCLUSION: There was no significant difference between fixation stiffness of a 3-part radial head fracture with headless compression screws in a tripod structure vs. a locking plate in Synbone. Further study is required to allow clinical application.

Scedosporium prolificans Septic Arthritis and Osteomyelitis of the Hip Joints in an Immunocompetent Patient: A Case Report and Literature Review.

Scedosporium prolificans, also known as Scedosporium inflatum, is a fungus widespread in soil, sewage, and manure. This species is highly virulent and is an emerging opportunistic pathogen found in penetrating injuries in immunocompromised patients. Here we report on an immunocompetent patient with bilateral hip S. prolificans-associated osteomyelitis and septic arthritis caused by intentional penetrating trauma. The condition was refractory to initial antimicrobial suppression and surgical irrigation and debridement. Successful outcome was achieved after incorporating a bilateral two-stage total-hip-arthroplasty with Voriconazole-loaded cement and spacer.

Effectiveness of the surgical torque limiter: a model comparing drill- and hand-based screw insertion into locking plates.

BACKGROUND: The objective of this study is to analyse the effectiveness of the surgical torque limiter during operative use. The study also investigates the potential differences in torque between hand and drill-based screw insertion into locking plates using a standardised torque limiter. METHODS: Torque for both hand and power screw insertion was measured through a load cell, registering 6.66 points per second. This was performed in a controlled environment using synthetic bone, a locking plate and locking screws to simulate plate fixation. Screws were inserted by hand and by drill with torque values measured. RESULTS: The surgical torque limiter (1.5 Nm) was effective as the highest recorded reading in the study was 1.409 Nm. Comparatively, there is a statistically significant difference between screw insertion methods. Torque produced for manually driven screw insertion into locking plates was 1.289 Nm (95 % CI 1.269-1.308) with drill-powered screw insertion at 0.740 Nm (95 % CI 0.723-0.757). CONCLUSIONS: The surgical torque limiter proved to be effective as per product specifications. Screws inserted under power produce significantly less torque when compared to manual insertion by hand. This is likely related to the mechanism of the torque limiter when being used at higher speeds for which it was designed. We conclude that screws may be inserted using power to the plate with the addition of a torque limiter. It is recommended that all screws inserted by drill be hand tightened to achieve adequate torque values.

Anatomic Variation in Volar Tilt of the Scaphoid and Lunate Facet of the Distal Radius.

PURPOSE: The aim of distal radial fracture treatment is to achieve optimal function through the restoration of normal anatomy, including volar tilt. The accuracy of assessing volar tilt on standard lateral radiographs compared with anatomic tilt lateral (ATL) radiographs is uncertain. This study aimed to investigate the anatomy of the articular surface of the distal radius, in particular measuring the angle between the dorsal and volar rims at several points from radial to ulnar, to ascertain whether volar tilt is uniform between the scaphoid and lunate facet and to explore consistency between standard lateral and ATL views. METHODS: We studied 38 dry cadaveric specimens of radii. The distal articular surface of each specimen was marked at 5 intervals and placed in a customized jig. A 1.5-mm stylus was placed at each marker to represent the articular surface angle, and was photographed in standard lateral and ATL projections. An on-screen protractor was used to measure each angle from the digital photographs. RESULTS: The volar tilt measurements at the lunate facet demonstrated a significantly shallower angle than those at the scaphoid facet. The measurements between the standard lateral and ATL were found to have no significant difference. CONCLUSIONS: Adjusting the projection angle between a simulated standard lateral and ATL view did not significantly change the volar tilt measurements in this anatomic study. The lunate facet was found to have a significantly shallower volar tilt than the scaphoid facet. Variance in radiographic volar tilt may relate to different anatomic sagittal planes, reflecting the anatomic variation between the scaphoid and lunate facets. CLINICAL RELEVANCE: A detailed understanding of distal radius anatomy is required by the surgeon for accurate radiologic interpretation and anatomic fracture reduction and fixation.

Irreducible Lateral Patellar Dislocation: A Case Report and Literature Review.

BACKGROUND: Acute patellar dislocation is a common injury in young people, especially in adolescent females and athletes. Lateral dislocation is the most common form of patellar dislocation and often reduces spontaneously or with simple manipulation and closed reduction. We report a rare circumstance in which the patella was irreducible and required manipulation and closed reduction in the operating room. CASE REPORT: While dancing, a 32-year-old female was knocked by a fellow dancer on her left knee, and she fell to the nightclub floor. She was unable to stand or bear weight because of the pain, and her knee was in fixed flexion with lateral displacement of the patella. Multiple attempts at closed reduction under sedation failed in the emergency department. Computed tomography (CT) images revealed a medial border patellar fracture and lipohemarthrosis that required closed reduction and manipulation in the operating room. The patient was placed in a Richards splint for follow-up and referred to a physiotherapist for conservative management. CONCLUSION: This case highlights the fact that some lateral patellar dislocations are irreducible on initial attempts, particularly if a fracture is present or another mechanism of impingement impedes relocation. CT imaging is a valuable diagnostic tool, and manipulation under anesthesia or open reduction in the operating room may be necessary. Our review of the literature further highlights the complexity and potential problems associated with treatment of locked lateral patellar dislocations.

Clear cell carcinoma, not otherwise specified/hyalinising clear cell carcinoma of the salivary gland: The current nomenclature, clinical/pathological characteristics and management.

Clear cell carcinoma, not otherwise specified (NOS)/hyalinising clear cell carcinoma (HCCC) is a rare entity in salivary gland tumour. The aim of the research is to review the current concepts and characteristics of this carcinoma. The clinical and pathological data of the disease obtained from literature and two original cases were analysed. Overall, 152 cases were reviewed up to the year 2014. The carcinomas were noted often in woman, in the seventh decade of life, located in oral cavity and as early-stages cancers. On pathological examination, they were characterized by tumour cells having clear cell morphology with hyalinised stroma. Immunohistochemical studies revealed that the carcinoma is positive for cytokeratin and negative for myoepithelial differentiation. EWSR1-ATF1 fusion is specific for the carcinoma. Also, 9% of the reported cases had local nodal metastasis, with 6 cases demonstrating distant metastases at presentation. On follow-up, 22% of patients had recurrent or with persistent diseases after surgery. The time for the first recurrence could be as long as 24 years. Risk factors for recurrence include advanced stage at diagnosis and metastases at presentation. To conclude, HCCC is a low grade malignancy but have the potential for local metastases, recurrence, distant metastases and cancer-related death.

Punching Glass: A 10-Year Consecutive Series.

INTRODUCTION: Punching glass can cause severe and debilitating injuries. The literature is scant in regards to the injury patterns, optimal management, and preventative strategies. We have reviewed our experience of these injuries at a regional Australian hospital. METHODS: A retrospective chart review of all patients who had punched glass and presented to Cairns Base Hospital between January 2003 and December 2012. Data collected included age, gender, marital status, employment status, alcohol consumption, side of injury, intent, time of presentation, damaged structures, treatment required, operative time, total hospital stay, and required follow-up. RESULTS: 137 eligible patients were identified during the 10-year study period. Mean age was 26.3 years. Most were men (n = 113), single (n = 122), unemployed (n = 95), and intoxicated (n = 91). Most of these injuries presented outside of normal working hours (P < 0.001). Ninety-one patients had superficial skin lacerations only and did not require operative intervention. The remaining 46 patients had a total of 46 tendon, 18 muscle, 12 nerve, 8 vessel and 5 bone injuries, and all required operative intervention. Tendon, nerve and vessel injuries were strongly associated with each other (P < 0.05). CONCLUSIONS: This represents the largest case series of glass punching injuries in the English literature. Punching glass can cause significant morbidity in a young age group and is therefore a major public health concern. Thorough physical examination, appropriate imaging and operative repair can improve outcomes. Preventative measures such as stricter legislation and safety glass will reduce the burden of these injures on the individual and healthcare system in Australia.

An extended and total flux normalized correlation equation for predicting single-collector efficiency.

In this study a novel total flux normalized correlation equation is proposed for predicting single-collector efficiency under a broad range of parameters. The correlation equation does not exploit the additivity approach introduced by Yao et al. (1971), but includes mixed terms that account for the mutual interaction of concomitant transport mechanisms (i.e., advection, gravity and Brownian motion) and of finite size of the particles (steric effect). The correlation equation is based on a combination of Eulerian and Lagrangian simulations performed, under Smoluchowski-Levich conditions, in a geometry which consists of a sphere enveloped by a cylindrical control volume. The normalization of the deposited flux is performed accounting for all of the particles entering into the control volume through all transport mechanisms (not just the upstream convective flux as conventionally done) to provide efficiency values lower than one over a wide range of parameters. In order to guarantee the independence of each term, the correlation equation is derived through a rigorous hierarchical parameter estimation process, accounting for single and mutual interacting transport mechanisms. The correlation equation, valid both for point and finite-size particles, is extended to include porosity dependency and it is compared with previous models. Reduced forms are proposed by elimination of the less relevant terms.

Solvent structuring and its effect on the polymer structure and processability: the case of water-acetone poly-ε-caprolactone mixtures.

One of the most common processes to produce polymer nanoparticles is the solvent-displacement method, in which the polymer is dissolved in a "good" solvent and the solution is then mixed with an "anti-solvent". The polymer processability is therefore determined by its structural and transport properties in solutions of the pure solvents and at the intermediate compositions. In this work, we focus on poly-ε-caprolactone (PCL) which is a biocompatible polymer that finds widespread application in the pharmaceutical and biomedical fields, performing full atomistic molecular dynamics simulations of one PCL chain of different molecular weight in a solution of pure acetone (good solvent), of pure water (antisolvent), and their mixtures. Our simulations reveal that the nanostructuring of one of the solvents in the mixture leads to an unexpected identical polymer structure irrespectively of the concentration of the two solvents. In particular, although in pure solvents the behavior of the polymer is, as expected, very different, at intermediate compositions, the PCL chain shows properties very similar to those found in pure acetone as a result of the clustering of the acetone molecules in the vicinity of the polymer chain. We derive an analytical expression to predict the polymer structural properties in solution at different solvent compositions and show that the solvent clustering affects in an unpredictable way the polymer diffusion coefficient. These findings have important consequences on the optimization of the nanoparticle production process and in the implementation of continuum modeling techniques to model it.

Blood lead, manganese, and aluminum levels in a regional Italian cohort of ALS patients: does aluminum have an influence?

OBJECTIVES: To study aluminum (Al), manganese (Mn), and lead (Pb) influence on amyotrophic lateral sclerosis (ALS) development. METHODS: A total of 34 patients (10% of the regional ALS population) and 25 controls of an Italian region were enrolled. Metal concentrations were determined by atomic absorption spectroscopy. RESULTS: Serum Al concentrations in patients and controls were similar and lower than those provided by the Italian Society of Reference Values. No differences were observed in serum Mn concentrations, while, as expected, blood Pb levels were significantly higher in patients with ALS than those in controls. CONCLUSIONS: Results confirmed the association between high Pb blood levels and ALS; on the contrary, Al and Mn did not differ significantly in patients and controls, suggesting that Mn and especially Al may play a less important role in the ALS pathogenesis.

Accumulation of altered aspartyl residues in erythrocyte membrane proteins from patients with sporadic amyotrophic lateral sclerosis.

Spontaneous protein deamidation of labile asparagines (Asn), generating abnormal l-isoaspartyl residues (IsoAsp), is associated with cell aging and enhanced by an oxidative microenvironment. The presence of isopeptide bonds impairs protein structure/function. To minimize the damage, IsoAsp can be "repaired" by the protein l-isoaspartyl/d-aspartyl O-methyltransferase (PIMT) and S-adenosylmethionine (AdoMet) is the methyl donor of this reaction. PIMT is a repair enzyme that initiates the conversion of l-isoAsp (or d-Asp) residues to l-Asp residues. Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease principally affecting motor neurons. The condition of oxidative stress reported in familial and sporadic forms of ALS prompted us to investigate Asn deamidation in ALS tissue. Erythrocytes (RBCs) were selected as a model system since they are unable to replace damaged proteins and protein methylesterification is virtually the only AdoMet-consuming reaction operating in these cells. Our data show that, in vitro assay, abnormal IsoAsp residues were significantly higher in ALS patients erythrocyte membrane proteins with an increased methyl accepting capability relative to controls (p<0.05). Moreover, we observed a reduction in AdoMet levels, while AdoHcy concentration was comparable to that detected in the control, resulting in a lower [AdoMet]/[AdoHcy] ratio. Then, the accumulation of altered aspartyl residues in ALS patients is probably related to a reduced efficiency of the S-adenosylmethionine (AdoMet)-dependent repair system causing increased protein instability at Asn sites. The increase of abnormal residues represents a new protein alteration that may be present not only in red blood cells but also in other cell types of patients suffering from ALS.

Clinical features and lifestyle of patients with amyotrophic lateral sclerosis in Campania: brief overview of an Italian database.

BACKGROUND: Physical activity and occupational exposures appeared to play a relevant role in pathogenesis of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease of unknown origin. MATERIALS AND METHODS: We aimed to make an overview of the clinical characteristics and lifestyle (occupation and sport) of a population of 395 patients with ALS from Campania, in southern Italy. RESULTS: ALS onset resulted anticipated of about 11 years in industry workers, whilst the more frequent site of onset among farmers was upper limbs. Compared to non-athletes, athletes, particularly soccer players, showed a 7 years anticipation of ALS onset, with higher mortality after 5 years. DISCUSSION AND CONCLUSIONS: We suggest that subjects genetically prone to abnormal response to hypoxia during strenuous physical activity or exposed to neurotoxic agents, such as athletes, farmers or industry workers, might present increased risk to develop ALS. Future case-control and follow-up studies on our population should be implemented to deepen the present results.