Deep geometry of subduction below the Andean belt of Colombia as revealed by seismic tomography

In this study new tomographic models of Colombia were calculated. I used the seismicity recorded by the Colombian seismic network during the period 2006-2009. In this time period, the improvement of the seismic network yields more stable hypocentral results with respect to older data set and allows to compute new 3D Vp and Vp/Vs models. The final dataset consists of 10813 P- and 8614 S-arrival times associated to 1405 earthquakes. Tests with synthetic data and resolution analysis indicate that velocity models are well constrained in central, western and southwestern Colombia to a depth of 160 km; the resolution is poor in the northern Colombia and close to Venezuela due to a lack of seismic stations and seismicity. The tomographic models and the relocated seismicity indicate the existence of E-SE subducting Nazca lithosphere beneath central and southern Colombia. The North-South changes in Wadati-Benioff zone, Vp & Vp/Vs pattern and volcanism, show that the downgoing plate is segmented by slab tears E-W directed, suggesting the presence of three sectors. Earthquakes in the northernmost sector represent most of the Colombian seimicity and concentrated on 100-170 km depth interval, beneath the Eastern Cordillera. Here a massive dehydration is inferred, resulting from a delay in the eclogitization of a thickened oceanic crust in a flat-subduction geometry. In this sector a cluster of intermediate-depth seismicity (Bucaramanga Nest) is present beneath the elbow of the Eastern Cordillera, interpreted as the result of massive and highly localized dehydration phenomenon caused by a hyper-hydrous oceanic crust. The central and southern sectors, although different in Vp pattern show, conversely, a continuous, steep and more homogeneous Wadati-Benioff zone with overlying volcanic areas. Here a "normalthickened" oceanic crust is inferred, allowing for a gradual and continuous metamorphic reactions to take place with depth, enabling the fluid migration towards the mantle wedge.

Differenze nella prestazione tecnico-tattica tra diverse categorie di atleti nel tennistavolo di alto livello

Nell’ambito della ricerca scientifica nel campo dello sport, la Performance Analysis si sta ritagliando un crescente spazio di interesse. Per Performance Analysis si intende l’analisi della prestazione agonistica sia dal punto di vista biomeccanico che dal punto di vista dell’analisi notazionale. In questa tesi è stata analizzata la prestazione agonistica nel tennistavolo attraverso lo strumento dell’analisi notazionale, partendo dallo studio degli indicatori di prestazione più importanti dal punto di vista tecnico-tattico e dalla loro selezione attraverso uno studio sull’attendibilità nella raccolta dati. L’attenzione è stata posta quindi su un aspetto tecnico originale, il collegamento spostamenti e colpi, ricordando che una buona tecnica di spostamento permette di muoversi rapidamente nella direzione della pallina per effettuare il colpo migliore. Infine, l’obbiettivo principale della tesi è stato quello di confrontare le tre categorie di atleti selezionate: alto livello mondiale maschile (M), alto livello junior europeo (J) ed alto livello mondiale femminile (F). La maggior parte delle azioni cominciano con un servizio corto al centro del tavolo, proseguono con una risposta in push (M) o in flik di rovescio (J). Il colpo che segue è principalmente il top spin di dritto dopo un passo pivot o un top di rovescio senza spostamento. Gli alteti M e J contrattaccano maggiormente con top c. top di dritto e le atlete F prediligono colpi meno spregiudicati, bloccando di rovescio e proseguendo con drive di rovescio. Attraverso lo studio della prestazione di atleti di categorie e generi diversi è possibile migliorare le scelte strategiche prima e durante gli incontri. Le analisi statistiche multivariate (modelli log-lineari) hanno permesso di validare con metodo scientifico sia le procedure già utilizzate in letteratura che quelle innovative messe a punto per la prima volta in occasione di questo studio.

Efficacia clinica dello stanozololo intrarticolare nella terapia dell'osteoartrosi di gomito nel cane

Il trattamento dell’osteoartrosi (OA) del cane è una sfida nella pratica clinica veterinaria. Molti trattamenti sono stati proposti, tuttavia la risposta clinica agli stessi non è sempre soddisfacente. Molti farmaci sono utilizzati per il trattamento dell’OA, tra cui farmaci anti-infiammatori non steroidei, corticosteroidi, ed inibitori della produzione dell’ossido nitrico. Lo stanozololo è un derivato sintetico del testosterone; oltre alle sue proprietà anaboliche/androgeniche , a basse dosi lo stanozololo ha un affinità per i recettori glucocorticoidi. Per questa attività antinfiammatoria e rigenerativa sui tessuti articolari danneggiati viene utilizzato nella degenerative joint desease del cavallo. Lo scopo di questo studio è stato di valutare l’efficacia clinica dello stanozololo intra-articolare a 15, 30, 45 e 60 giorni dal trattamento di gomiti con OA di cane. E’ stato eseguito uno studio cieco, multicentrico e randomizzato. Previo consenso informato, sono stati arruolati 48 cani, suddivisi in 3 gruppi e trattati con stanozololo, mavacoxib e con entrambi i farmaci. Sono state valutate zoppia, tollerabilità del trattamento, range of motion, e punteggio radiografico. Inoltre sono state stabilite e annoverate quantità e qualità del liquido sinoviale. Ai dati ottenuti sono stati applicati i test di Kruskal-Wallis, Chi-quadro e Fischer, i quali hanno dimostrato l’efficacia della terapia nei singoli gruppi e tra i diversi gruppi di studio. I risultati ottenuti hanno mostrato la riduzione di almeno un grado di zoppia e la riduzione della progressione dell’OA nei casi trattati con stanozololo. Si può quindi affermare che tale molecola per via intra-articolare può essere una valida alternativa per il trattamento dell’OA di gomito nel cane.

Reversed shoulder arthroplasty with modified L'Episcopo for combined loss of active elevation and external rotation

In patients with a rotator cuff-deficient shoulder, a combined loss of active elevation and external rotation (CLEER) can occur when both the infraspinatus and teres minor muscles are absent. A reverse shoulder arthroplasty (RSA) can restore active elevation in these patients but cannot restore active external rotation because there are no other external rotator cuff muscles. We hypothesized that a modified L'Episcopo procedure (latissimus dorsi [LD] and teres major [TM] transfer) with a simultaneous RSA would restore shoulder function and activities of daily living (ADLs).

On-table reconstruction of comminuted fractures of the radial head

The most widely accepted treatment for comminuted fractures of the radial head is either the excision or open reduction and internal fixation. The purpose of the present study is to evaluate the value of an 'on-table' reconstruction technique in severely comminuted fractures of the radial head. In this study, two patients with a Mason type-III and four patients with a Mason type-IV radial-head fracture were treated with 'on-table' reconstruction and fixation using low-profile mini-plates. After a mean follow-up of 112 months (47-154 months), the mean elbow motion was 0-6-141 degrees extension flexion with 79 degrees of pronation and 70 degrees of supination. The mean Broberg and Morrey functional rating score was 97.0 points, the Mayo Elbow Performance Index was 99.2 points and the mean Disabilities of the Arm, Shoulder, and Hand (DASH) Outcome Measure score was 1.94 points. One patient had symptoms of degenerative changes, with a slight joint-space narrowing. There were no radiographic signs of devitalisation at final examination. Comminuted fractures of the radial head, which would otherwise require excision, can be successfully treated with an 'on-table' reconstruction technique.

Eosinophilic vasculitis: an inhabitual and resistant manifestation of a vasculitis

A 55-year-old woman was referred because of diffuse pruritic erythematous lesions and an ischemic process of the third finger of her right hand. She was known to have anaemia secondary to hypermenorrhea. She presented six months before admission with a cutaneous infiltration on the left cubital cavity after a paravenous leakage of intravenous iron substitution. She then reported a progressive pruritic erythematous swelling of her left arm and lower extremities and trunk. Skin biopsy of a lesion on the right leg revealed a fibrillar, small-vessel vasculitis containing many eosinophils.Two months later she reported Raynaud symptoms in both hands, with a persistent violaceous coloration of the skin and cold sensation of her third digit of the right hand. A round 1.5 cm well-delimited swelling on the medial site of the left elbow was noted. The third digit of her right hand was cold and of violet colour. Eosinophilia (19 % of total leucocytes) was present. Doppler-duplex arterial examination of the upper extremities showed an occlusion of the cubital artery down to the palmar arcade on the right arm. Selective angiography of the right subclavian and brachial arteries showed diffuse alteration of the blood flow in the cubital artery and hand, with fine collateral circulation in the carpal region. Neither secondary causes of hypereosinophilia nor a myeloproliferative process was found. Considering the skin biopsy results and having excluded other causes of eosinophilia, we assumed the diagnosis of an eosinophilic vasculitis. Treatment with tacrolimus and high dose steroids was started, the latter tapered within 12 months and then stopped, but a dramatic flare-up of the vasculitis with Raynaud phenomenon occurred. A new immunosuppressive approach with steroids and methotrexate was then introduced. This case of aggressive eosinophilic vasculitis is difficult to classify into the usual forms of vasculitis and constitutes a therapeutic challenge given the resistance to current immunosuppressive regimens.

A pedicled bone graft from the acromion: an anatomical investigation regarding surgical feasibility

To investigate the technical feasibility of harvesting a vascularized bone graft from the acromion pedicled on the acromial branch.

The unstable painful shoulder (UPS) as a cause of pain from unrecognized anteroinferior instability in the young athlete

The etiology of shoulder pain in the overhead athlete is often difficult to determine. This study hypothesized that (1) instability can present in a purely painful form, without any apparent history of instability, but with anatomic lesions indicative of instability, termed unstable painful shoulder (UPS), and that (2) arthroscopic shoulder stabilization is effective.

Comminuted fractures of the radial head and neck: is fixation to the shaft necessary?

Mason type III fractures of the radial head are treated by open reduction and internal fixation, resection or prosthetic joint replacement. When internal fixation is performed, fixation of the radial head to the shaft is difficult and implant-related complications are common. Furthermore, problems of devascularisation of the radial head can result from fixation of the plate to the radial neck. In a small retrospective study, the treatment of Mason type III fractures with fixation of the radial neck in 13 cases (group 2) was compared with 12 cases where no fixation was performed (group 1). The mean clinical and radiological follow-up was four years (1 to 9). The Broberg-Morrey index showed excellent results in both groups. Degenerative radiological changes were seen more frequently in group 2, and removal of the implant was necessary in seven of 13 cases. Post-operative evaluation of these two different techniques revealed similar ranges of movement and functional scores. We propose that anatomical reconstruction of the radial head without metalwork fixation to the neck is preferable, and the outcome is the same as that achieved with the conventional technique. In addition degenerative changes of the elbow joint may develop less frequently, and implant removal is not necessary.

Vibrating Membrane Devices Deliver Aerosols More Efficient than Standard Devices: A Study in a Neonatal Upper Airway Model

Abstract Background: Aerosol therapy in preterm infants is challenging, as a very small proportion of the drug deposits in the lungs. Aim: Our aim was to compare efficiency of standard devices with newer, more efficient aerosol delivery devices. Methods: Using salbutamol as a drug marker, we studied two prototypes of the investigational eFlow(®) nebulizer for babies (PARI Pharma GmbH), a jet nebulizer (Intersurgical(®) Cirrus(®)), and a pressurized metered dose inhaler (pMDI; GSK) with a detergent-coated holding chamber (AeroChamber(®) MV) in the premature infant nose throat-model (PrINT-model) of a 32-week preterm infant (1,750 g). A filter or an impactor was placed below the infant model's "trachea" to capture the drug dose or particle size, respectively, that would have been deposited in the lung. Results: Lung dose (percentage of nominal dose) was 1.5%, 6.8%, and 18.0-20.6% for the jet nebulizer, pMDI-holding chamber, and investigational eFlow nebulizers, respectively (p<0.001). Jet nebulizer residue was 69.4% and 10.7-13.9% for the investigational eFlow nebulizers (p<0.001). Adding an elbow extension between the eFlow and the model significantly lowered lung dose (p<0.001). A breathing pattern with lower tidal volume decreased deposition in the PrINT-model and device residue (p<0.05), but did not decrease lung dose. Conclusions: In a model for infant aerosol inhalation, we confirmed low lung dose using jet nebulizers and pMDI-holding chambers, whereas newer, more specialized vibrating membrane devices, designed specifically for use in preterm infants, deliver up to 20 times more drug to the infant's lung.

The effect of cementing technique on structural fixation of pegged glenoid components in total shoulder arthroplasty

Although loosening of cemented glenoid components is one of the major complications of total shoulder arthroplasty, there is little information about factors affecting initial fixation of these components in the scapular neck. This study was performed to assess the characteristics of structural fixation of pegged glenoid components, if inserted with two different recommended cementing techniques. Six fresh-frozen shoulder specimens and two types of glenoid components were used. The glenoids were prepared according to the instructions and with the instrumentation of the manufacturer. In 3 specimens, the bone cement was inserted into the peg receiving holes (n = 12) and applied to the back surface of the glenoid component with a syringe. In the other 3 specimens, the cement was inserted into the holes (n = 15) by use of pure finger pressure: no cement was applied on the backside of the component. Micro-computed tomography scans with a resolution of 36 microm showed an intact cement mantle around all 12 pegs (100%) when a syringe was used. An incomplete cement plug was found in 7 of 15 pegs (47%) when the finger-pressure technique was used. Cement penetration into the cancellous bone was deeper in osteopenic bone. Application of bone cement on the backside of the glenoid prosthesis improved seating by filling out small spaces between bone and polyethylene resulting from irregularities after reaming or local cement extrusion from a drill hole. The fixation of a pegged glenoid component is better if the holes are filled with cement under pressure by use of a syringe and if cement is applied to the back of the glenoid component than if cement is inserted with pure finger pressure and no cement is applied to the back surface of the component.

Effects of glenoid component version on humeral head displacement and joint reaction forces: an experimental study

The purpose of this study was to determine whether changes in glenoid version are associated with humeral head displacement and changes in the joint reaction forces, as these might contribute to instability or loosening in total shoulder replacement. A total shoulder prosthesis was implanted in neutral version in 6 cadaveric shoulders. Glenoid version was then changed in steps of 4 degrees toward more anteversion and retroversion. An increase in anteversion resulted in anterior translation of the humeral head and in eccentric loading of the anterior part of the glenoid. Retroversion was associated with posterior displacement and posterior loading of the glenoid. A change in rotation of the humeral component did not compensate for altered version of the glenoid component. These results suggest that both instability and glenoid component loosening may be related to the version of the glenoid component. Therefore, assessment of loosening and instability justifies precise assessment of glenoid component version.

Assessing the intra- and inter-reader reliability of dynamic ultrasound images in power Doppler ultrasonography

OBJECTIVE: To assess the intra-reader and inter-reader reliabilities of interpreting ultrasonography by several experts using video clips. METHOD: 99 video clips of healthy and rheumatic joints were recorded and delivered to 17 physician sonographers in two rounds. The intra-reader and inter-reader reliabilities of interpreting the ultrasound results were calculated using a dichotomous system (normal/abnormal) and a graded semiquantitative scoring system. RESULTS: The video reading method worked well. 70% of the readers could classify at least 70% of the cases correctly as normal or abnormal. The distribution of readers answering correctly was wide. The most difficult joints to assess were the elbow, wrist, metacarpophalangeal (MCP) and knee joints. The intra-reader and inter-reader agreements on interpreting dynamic ultrasound images as normal or abnormal, as well as detecting and scoring a Doppler signal were moderate to good (kappa = 0.52-0.82). CONCLUSIONS: Dynamic image assessment (video clips) can be used as an alternative method in ultrasonography reliability studies. The intra-reader and inter-reader reliabilities of ultrasonography in dynamic image reading are acceptable, but more definitions and training are needed to improve sonographic reproducibility.

Correlation of atrophy and fatty infiltration on strength and integrity of rotator cuff repairs: a study in thirteen patients

In 13 patients, the development of supraspinatus muscle atrophy and fatty infiltration after rotator cuff tendon repair was quantified prospectively via magnetic resonance imaging. Intraoperative electrical nerve stimulation at repair showed that the maximal supraspinatus tension (up to 200 N) strongly correlated with the anatomic cross-sectional muscle area and with muscle fatty infiltration (ranging from 12 N/cm(2) in Goutallier stage 3 to 42 N/cm(2) in Goutallier stage 0). Within 1 year after successful tendon repair (n = 8), fatty infiltration did not recover, and atrophy improved partially at best; however, if the repair failed (n = 5), atrophy and fatty infiltration progressed significantly. The ability of the rotator cuff muscles to develop tension not only correlates with their atrophy but also closely correlates with their degree of fatty infiltration. With current repair techniques, atrophy and fatty infiltration appear to be irreversible, despite successful tendon repair. Unexpectedly, not only weak but also very strong muscles are at risk for repair failure.