Ground state study of simple atoms within a nano-scale box

Ground state energies for confined hydrogen (H) and helium (He) atoms, inside a penetrable/impenetrable compartment have been calculated using Diffusion Monte Carlo (DMC) method. Specifically, we have investigated spherical and ellipsoidal encompassing compartments of a few nanometer size. The potential is held fixed at a constant value on the surface of the compartment and beyond. The dependence of ground state energy on the geometrical characteristics of the compartment as well as the potential value on its surface has been thoroughly explored. In addition, we have investigated the cases where the nucleus location is off the geometrical centre of the compartment.Comment: 9 pages, 5 eps figures, Revte

Spin polarization effect in 2D and Q2D electron gas

We use the constructed spin-dependent static local field functions to calculate the plasmon dispersion of two dimensional spin polarized electron gas (2D SPEG) over a range of electron densities at arbitrarily spin polarization. We also investigate how the finite width of electron layer will affect the plasmon frequency and inverse static dielectric function of 2D SPEG. Our results show that the effect of finite thickness on plasmon dispersion and inverse dielectric function becomes considerable even at high densities in 2D SPEG

A novel local adipofascial flap for the management of recalcitrant ulnar tunnel syndrome

Ulnar tunnel syndrome is the second most common upper-limb peripheral nerve compression syndrome. Recurrence or persistence of symptoms after primary surgery is found in 9.9%–21% of cases. The main cause of failure is peri- and endo-neural fibrosis, and management is difficult and controversial. Revision of nerve neurolysis combined with freestyle adipofascial flap provides nerve decompression and coverage with vascularized tissue, which prevents scar tissue formation around the nerve and restores glide. We performed a preliminary vessel-injected cadaver study. The perforating vessels from the posterior recurrent ulnar artery vascularize the medial adipose and fascial tissues of the elbow, allowing elevation of an adipofascial flap which is able to reach the ulnar nerve. Eight patients with neuropathic ulnar nerve pain in recalcitrant ulnar tunnel syndrome due to peri- and/or endo-neural fibrosis were treated by neurolysis, and the nerve was covered with an ulnar adipofascial flap. All patients were evaluated by percussion test, visual analog scale for pain, electromyography, electroneurography and ultrasound, and were classified according to the McGowan classification as modified by Goldberg. The study was approved by the review board. All patients had good 4-year outcome, with complete return to daily activity, work and sports 4 months after surgery. The results of this novel surgical technique were encouraging, without complications or donor site morbidity. Adipofascial flap combined with neurolysis could be a valid solution in the treatment of recalcitrant ulnar tunnel syndrome

Hip subluxation and dislocation in cerebral palsy:outcome of bone surgery in 21 hips

The prevalence of hip subluxation and dislocation in cerebral palsy ranges between 3% and 75% in the literature. Clinical signs are rigidity, pain and instability. We assessed functionality, stability and symptoms in 20 patients preoperatively and after follow-up. A varus derotation osteotomy was performed in cases with subluxation or dislocation, while a Chiari osteotomy was performed in the presence of a con- comitant acetabular dysplasia. Results were good in 64%, fair in 22% and poor in 14% of patients treated with a varus derotation osteotomy. In patients treated with a Chiari osteo- tomy, results were good in 43% of cases, fair in 43% and poor in 14%. Subluxated or dislocated hips generally show several anomalies : their severity is directly proportional to the degree of neurological impairment. In the most severe cases, correction of just one of such anomalies might not be sufficient to guarantee good results of the surgery

Idrossiapatite: dall’adesione alla clinica [Hydroxyapatite: from adhesion to the clinics]

Nelle protesi d’anca le proprietà dei materiali sono fondamentali. Questi interagiscono con il corpo principalmente a livello della superficie; inoltre la modulazione delle sue proprietà utilizzando differenti tipi di lavorazione o rivestimento, possono migliorare i risultati dell’impianto in modo significativo. Tra l’ampia gamma di rivestimenti, quelli in idrossiapatite hanno mostrato risultati particolarmente promettenti. I rivestimenti sono utilizzati per favorire la crescita ossea periprotesica, ridurre l’attrito, l’usura e la corrosione, e migliorare la biocompatibilità della protesi. Nel futuro prossimo sempre più attenzione nello sviluppo verrà dedicata ai biomateriali, nel tentativo di migliorare le performance tribologiche e, di conseguenza, la longevità dell’impianto.In hip replacements, the bulk properties of materials are important. The material interacts with the body mainly at the surfaces; therefore, the control of surface properties using different kinds of treatments or coatings may improve total hip replacements considerably. Among the large variety of coatings, hydroxyapatite coatings have shown promising results. This coating mainly are used to enhance bone growth; to minimize friction, wear, and corrosion; and to improve biocompatibility of total joint prostheses. It can be concluded that in the near future, more attention will be given for the development of coating methods, aimed to improve the tribologic performance and the longevity of implant