Optical properties of molybdenum in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy.

Optical properties of polycrystalline molybdenum are determined from ultraviolet up to extreme ultraviolet by reflection electron energy loss spectroscopy (REELS). Calculations are performed within the dielectric response theory by means of the quantitative analysis of electron energy losses at surfaces QUEELS-ϵ(k,ω)-REELS software [Surf. Interface Anal.36, 824 (2004)SIANDQ0142-242110.1002/sia.1774] that allows the simulation of inelastic scattering cross sections, using a parametric energy loss function describing the optical response of the material. From this energy loss function, the real and imaginary parts of the dielectric function, the refractive index, and the extinction coefficient are deduced and compared with previously published results.

Clinical results of radial arthroplasty in Hotchkiss' terrible triad, a case series of 47. / Resultados clínicos de la artroplastia radial en la tríada terrible de Hotchkiss, a propósito de 47 casos.

INTRODUCTION: Radial head fractures represent 33-75% of elbow fractures (30 cases/100,000 population/year). "Terrible triad's Hotchkiss" is characterized by radial head fracture, coronoid fracture and elbow dislocation. Our principal goal is to compare our results on each type of prosthesis in the context of the triad. MATERIAL AND METHODS: We conducted an observational, descriptive and retrospective study. Sample size was 47 patients. Variables analyzed were affiliation, Mason's classification, surgical aspects (moment of surgery, surgical time, prosthesis type, re-surgery), rehabilitation time, causes of prosthetic failure, complications, radiographic findings (according to van Riet), Popovic's loosening areas, MEPS and Cassebaum's scales. We performed an inter-group study, on patients treated with monopolar or bipolar prosthesis, in order to see results. RESULTS: Average age was 43.5±8.9 years. 72.7% were in highly demanding jobs. Mason's fracture type iv appeared in all the cases and Regan-Morrey's type I was the most frequent coronoid fracture (42.6%). There were 22 bipolar prosthesis and 25 monopolar prosthesis. Surgery time was about 112.3±59.1minutes. External fixation was used in 6.4%. MEPS final: 85.9±15 points. Rehabilitation time was about 4.7±2.5 months. Of the patients, 76.6% returned to work. Cassebaum's results were good-excellent in 74.5% of patients. There were 3 cases of prosthetic mobilization. Heterotopic ossification appeared in 29.8% of cases and 15.2% presented overstuffing. With regard to the inter-group study, we observed that there was less surgical time with monopolar prosthesis (P=.006), fewer second look surgeries (P=.05), less stiffness (P=.04), less heterotopic ossification (P=.004) and septic loosening (P=.005), without any influence on MEPS (P=.44). CONCLUSIONS: Results obtained in terrible triads with prostheses in our experience are good. Prosthetic type influences results, because surgical time for implantation of a monopolar prosthesis was less than for a bipolar one, although rehabilitation time was longer. With bipolar prostheses, external fixation was required, with a higher rate of reinterventions, stiffness, prosthetic mobilization, heterotopic ossification and prosthetic loosening. However, there were no differences between the 2prosthetic types in terms of clinical results, like MEPS or Cassebaum scores.

Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet.

Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 keV. This technique allows the evaluation of the optical response in these ultraviolet spectral regions of a thin layer of material, and the analysis is straightforward. It is performed within the dielectric response theory by means of the QUEELS-ε(k, ω)-REELS software developed by Tougaard and Yubero [Surf. Interface Anal.36, 824 (2004)SIANDQ0142-242110.1002/(ISSN)1096-9918]. The method consists basically in the fitting of experimentally determined single-scattering electron energy loss cross sections with a parametric energy loss function of the corresponding material, to the one calculated within a dielectric response formalism. The obtained refractive index and extinction coefficients, as well as the identified electronic transitions are compared, when available, with previously published results.

Laser Treatment of Nanoparticulated Metal Thin Films for Ceramic Tile Decoration.

This paper presents a new method for the fabrication of metal-like decorative layers on glazed ceramic tiles. It consists of the laser treatment of Cu thin films prepared by electron-beam evaporation at glancing angles. A thin film of discontinuous Cu nanoparticles was electron-beam-evaporated in an oblique angle configuration onto ceramic tiles and an ample palette of colors obtained by laser treatment both in air and in vacuum. Scanning electron microscopy along with UV-vis-near-IR spectroscopy and time-of-flight secondary ion mass spectrometry analysis were used to characterize the differently colored layers. On the basis of these analyses, color development has been accounted for by a simple model considering surface melting phenomena and different microstructural and chemical transformations of the outmost surface layers of the samples.

Portable IR dye laser optofluidic microresonator as a temperature and chemical sensor.

A compact and portable optofluidic microresonator has been fabricated and characterized. It is based on a Fabry-Perot microcavity consisting essentially of two tailored dichroic Bragg mirrors prepared by reactive magnetron sputtering deposition. The microresonator has been filled with an ethanol solution of Nile-Blue dye. Infrared laser emission has been measured with a pump threshold as low as 0.12 MW/cm2 and an external energy conversion efficiency of 41%. The application of the device as a temperature and a chemical sensor is demonstrated. Small temperature variations as well as small amount of water concentrations in the liquid laser medium are detected as a shift of the resonant laser modes.

Use of grafts in rotator cuff re-rupture. / Utilización de injertos en la reparación de rerroturas del manguito rotador.

INTRODUCTION AND OBJECTIVES: Rotator cuff re-ruptures appear in 38-65% of cases. In order to reduce this rate, many studies have been performed using different types of biomaterial for purely mechanical aims (re-inforce the suture) and/or biological agents (growth factor transporterts). The aim of this study is to review 22 cases treated with xenografts and analyse various current alternatives. MATERIALS AND METHODS: A descriptive and retrospective study was conducted using the variables of age, sex, laterality, time of surgery, involvement in MRI, number of anchors, and final mobility results on the Constant and the University of California Los Angeles (UCLA) validated scales. RESULTS: The study included 22 patients, with a mean age of 51.7±4.6 years. A mean of 2 anchors were used and 13 patients were treated with a porcine intestinal submucosa implant, 6 with equine pericardium, and 3 with porcine dermis. Final results were: 37.6±13 points for the Constant test, and 16.9±3.9 points on the UCLA scale. The follow up was 36±10.2 months. CONCLUSIONS: In our experience, xenografts could provide good functional results and they would be a surgical alternative to tendon transfers in cases of massive tears. Further studies should be conducted with other biomaterials.

Radial head arthroplasty, 11 years experience: A series of 82 patients.

OBJECTIVES: The indications for radial head arthroplasty are essentially complex fractures with ligament damage (medial, lateral or Essex-Lopresti), and/or associated with bone damage (coronoids or olecranon). The aim of this study is to review our experience with the use of a radial head prosthesis in the context of a trauma. MATERIAL AND METHOD: An observational, descriptive and retrospective study, with a follow-up of 1- 11 years, was performed on a study group of 82 patients with a mean age of 41.6 (± 9.2) years. The inclusion criteria were: patients of working age (25-64 years) with complex radial head fractures (Mason II, III, IV), with soft tissue and bone injuries that caused instability, non-reconstructable by osteosynthesis and treated using arthroplasty. The primary variables analysed were social demographics, Mason classification, or surgical aspects such as delay, surgical time, type of prosthesis (where the bipolar prosthesis was most used, 88.6%), need of fixation or further surgery. Rehabilitation time, causes of prosthesis failure, radiological findings (according to Van-Riet), areas of loosening (according to Popovic), as well as the Mayo Elbow Performance Score (MEPS) and the Cassebaum scale. Various associated injuries were observed, such as injuries in the lateral collateral ligament of the elbow in 39% of cases, coronoid fractures in 25.6%, and an olecranon fracture in 15.9% of the series. There was one case of an Essex- Lopresti injury. The tests used for the statistical analysis were Chi squared and Fisher test for categorical variables and contingency tables. The Mann Whitney U or Kruskall Wallis tests were used for the numerical variables. Evidence level: IV. RESULTS: The mean surgical time was 100 (± 56.8) minutes. The prosthesis was fixed in 53.8% of cases. The mean score on the MEPS scale was 80.4 (± 19.3) points, being good-excellent in 71.6%. The elbow was stable in 93.7% of cases. There was moderate instability, with 10° or more in varus or valgus, and in 1.3% in the rest of the series. The rehabilitation time was lower in the fixed cases (P=.03), and there was greater rigidity (P=.03) and more sequelae (limitations in mobility, residual pain), (P<0.05) in the cases where the LCL had to be repaired (given that there were other serious injuries in these cases). When the surgical delay was less than one week, better results were obtained on the Cassebaum scale (P=.02), as well as more excellent results on the MEPS scale MEPS (P=.02). The prosthesis was removed in 11 cases (13.4%), with the main cause for removal being pain in pronosupination in 5 cases, and capitellar injuries in 4 cases, one dislocation, and one infections. The most frequent complication was rigidity (30.5%). There were 3 infections (3.7%). Popovic areas 1 and 7 had greater osteolysis. CONCLUSIONS: The presence of concomitant bone and ligament injuries determined a longer surgical time and more sequelae. Early surgery would achieve better clinical results.

DLC coatings for UHMWPE: relationship between bacterial adherence and surface properties.

Development of intrinsically antibacterial surfaces is of key importance in the context of prostheses used in orthopedic surgery. This work presents a thorough study of several plasma-based coatings that may be used with this functionality: diamond-like carbon (DLC), fluorine-doped DLC (F-DLC), and a high-fluorine-content-carbon-fluor polymer (CF(X)). The coatings were obtained by a radio-frequency plasma-assisted deposition on ultra high molecular weight polyethylene (UHMWPE) samples and physicochemical properties of the coated surfaces were correlated with their antibacterial performance against collection and clinical Staphylococcus aureus and Staphylococcus epidermidis strains. The fluorine content and the relative amount of C-C and C-F bonds were controlled by X-ray photoelectron spectroscopy, and hydrophobicity and surface tension by contact angle measurements. Surface roughness was studied by Atomic Force Microscopy. Additional nanoidentation studies were performed for DLC and F-DLC coatings. Unpaired t test and regression linear models evaluated the adherence of S. aureus and S. epidermidis on raw and coated UHMWPE samples. Comparing with UHMWPE, DLC/UHMWPE was the least adherent surface with independence of the bacterial species, finding significant reductions (p ≤ 0.001) for nine staphylococci strains. Bacterial adherence was also significantly reduced in F-DLC/ UHMWPE and CFx/UHMWPE for six strains.

Bacterial adherence on UHMWPE with vitamin E: an in vitro study.

Orthopaedic materials may improve its capacity to resist bacterial adherence, and subsequent infection. Our aim was to test the bacterial adherence to alpha-tocopherol (frequently named vitamin E, VE) doped or blended UHMWPE with S. aureus and S. epidermidis, compared to virgin material. Collection strains and clinical strains isolated from patients with orthopaedic infections were used, with the biofilm-developing ability as a covariable. While collection strains showed significantly less adherence to VE-UHMWPE, some clinical strains failed to confirm this effect, leading to the conclusion that VE doped or blended UHMWPE affects the adherence of some S. epidermidis and S. aureus strains, independently of the concentration in use, but the results showed important intraspecies differences and cannot be generalized.

Effect of surface roughness and sterilization on bacterial adherence to ultra-high molecular weight polyethylene.

Sterilization with ethylene oxide (EO) and gas plasma (GP) are well-known methods applied to ultra-high molecular weight polyethylene (UHMWPE) surfaces in the belief that they prevent major material changes caused by gamma irradiation. However, the influence of these surface sterilization methods on bacterial adherence to UHMWPE is unknown. UHMWPE samples with various degrees of roughness (0.3, 0.8 and 2.0 µm) were sterilized with either GP or EO. The variations in hydrophobicity, surface free energy and surface functional groups were investigated before and after sterilization. Sterilized samples were incubated with either Staphylococcus aureus or Staphylococcus epidermidis in order to study bacterial adherence to these materials. Fewer bacteria adhered to UHMWPE after sterilization with EO than after sterilization with GP, especially to the smoothest surfaces. No changes in chemical composition of the UHMWPE surface due to sterilization were observed using X-ray photoemission spectroscopy analysis. The decreased bacterial adherence to UHMWPE found at the smoothest surfaces after sterilization with EO was not directly related to changes in chemical composition. Increased bacterial adherence to rougher surfaces was associated with increased polar surface energy of EO-sterilized surfaces.

Non-destructive depth compositional profiles by XPS peak-shape analysis.

The measured peak shape and intensity of the photoemitted signal in X-ray photoelectron spectroscopy (XPS) experiments (elastic and inelastic parts included) are strongly correlated, through electron-transport theory, with the depth distribution of photoelectron emitters within the analyzed surface. This is the basis of so-called XPS peak-shape analysis (also known as the Tougaard method) for non-destructive determination of compositional in-depth (up to 6-8 nm) profiles. This review describes the theoretical basis and reliability of this procedure for quantifying amounts and distributions of material within a surface. The possibilities of this kind of analysis are illustrated with several case examples related to the study of the initial steps of thin-film growth and the modifications induced in polymer surfaces after plasma treatments.