Tight-binding variable-charge model for insulating oxides: Application to TiO

We have developed a new variable-charge model aimed at performing large-scale realistic simulations of oxide surfaces and interfaces. This model is based on the charge equilibration (QEq) method and explicitly takes into account the mixed iono-covalent character of the metal-oxygen bond by means of a tight-binding analytical approach. We present the first results obtained for TiO2 and ZrO2 polymorphs, which are in very good agreement with the experimental data and recent ab initio results

Use of a variable-charge interatomic potential for atomistic simulations of bulk, oxygen vacancies, and surfaces of rutile TiO 2

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Challenging a classic myth: pneumoperitoneum associated with acute diverticulitis is not an indication for open or laparoscopic emergency surgery in hemodynamically stable patients. A 10-year experience with a nonoperative treatment.

Background In patients presenting with acute diverticulitis (AD) and signs of acute peritonitis, the presence of extradigestive air (EDA) on a computer tomography (CT) scan is often considered to indicate the need for emergency surgery. Although the traditional management of “perforated” AD is open sigmoidectomy, more recently, laparoscopic drainage/lavage (usually followed by delayed elective sigmoidectomy) has been reported. The aim of this retrospective study is to evaluate the results of nonoperative management of emergency patients presenting with AD and EDA. Methods The outcomes of 39 consecutive hemodynamically stable patients (23 men, mean age = 54.7 years) who were admitted with AD and EDA and were managed nonoperatively (antibiotic and supportive treatment) at a tertiary-care university hospital between January 2001 and June 2010 were retrospectively collected and analyzed. These included morbidity (Clavien-Dindo) and treatment failure (need for emergency surgery or death). A univariate analysis of clinical, radiological, and laboratory criteria with respect to treatment failure was performed. Results of delayed elective laparoscopic sigmoidectomy were also analyzed. Results There was no mortality. Thirty-six of the 39 patients (92.3%) did not need surgery (7 patients required CT-guided abscess drainage). Mean hospital stay was 8.1 days. Duration of symptoms, previous antibiotic administration, severe sepsis, PCR level, WBC concentration, and the presence of abdominal collection were associated with treatment failure, whereas “distant” location of EDA and free abdominal fluid were not. Five patients had recurrence of AD and were treated medically. Seventeen patients (47.2%) underwent elective laparoscopic sigmoidectomy for which mean operative time was 246 min (range = 100–450) and the conversion rate was 11.8%. Mortality was nil and the morbidity rate was 41.2%. Mean postoperative stay was 7.1 days (range = 4–23). Conclusions Nonoperative management is a viable option in most emergency patients presenting with AD and EDA, even in the presence of symptoms of peritonitis or altered laboratory tests. Delayed laparoscopic sigmoidectomy may be useless in certain cases and its results poorer than expected

Ann Phys Rehabil Med

BACKGROUND: Epicondylar tendinopathy ("tennis elbow") is a serious issue in manual labourers. Symptoms can persist over months or even more than 1 year, even when treated with trinitrine patches, acupuncture, sclerosis of neovessels, shock-wave therapy, autologous blood injections, platelet-rich plasma or hyaluronic acid. Botulinum toxin (BoNT-A) injections showed promising short-term results, but the long-term beneficial effects are not yet known. OBJECTIVE: We aimed to assess the long-term effect, side effects and recurrence rate after BoNT-A injections on chronic lateral epicondylar tendinopathy during 1 year. METHODS: This open study followed a 3-month randomized controlled trial. We included 50 patients followed at day 0 (V0), 90 (V1), 180-270 (V2) and 365 (V3). The main judgment criterion was the number of BoNT-A injections required to achieve pain relief with no further request for treatment by the patient. RESULTS: After one BoNT-A injection, 22/50 (44%) patients did not ask for further treatment during follow-up because of complete pain relief, and 20/50 (40%) asked for a second BoNT-A injection. For 20 patients with a second injection, 18 (90%) did not ask for further treatment during follow-up. Only 1 patient had a recurrence of pain after an initial pain relief of greater than 75%. Quality of life, and painful and maximal gripping force improved significantly at V1, V2 and V3 as compared with V0, and repercussions on daily and professional activities decreased significantly (P<0.05). CONCLUSIONS: One or 2 BoNT-A injections has favourable results for chronic epicondylar tendinopathy

From metastability to equilibrium during the sequential growth of Co-Ag supported clusters: a real-time investigation

: Atomic motions and morphological evolution of growing Co-Ag nanoparticles are followed in situ and in real time, by wide and small angle X-ray scattering obtained simultaneously in grazing incidence geometry (GISAXS and GIWAXS), in single or multi-wavelength anomalous modes. The structural analysis of the experimental data is performed with the aid of equilibrium Monte Carlo simulations and of molecular-dynamics simulations of nanoparticle growth. Growth is performed by depositing Co atoms above preformed Ag nanoparticles. This growth procedure is strongly out of equilibrium, because Ag tends to surface segregation, and generates complex growth sequences. The real time analysis of the growth allows to follow the nanoparticle evolution pathways almost atom-by-atom, determining the key mechanisms during Co deposition: starting with the incorporation of Co atoms in sub-surface positions, to the off-center Co domain formation, then by which the nanoparticles finally approach their equilibrium quasi-Janus then core-shell structures

Hemoperitoneum caused by a ruptured GIST located in the posterior gastric wall managed by endoscopic diagnosis and laparoscopic treatment: case report and literature review.

A case of hemoperitoneum caused by a ruptured gastrointestinal stromal tumor (GIST) of the posterior gastric wall is presented. An otherwise healthy 81-year-old man presented with abdominal pain/tenderness and anemia (hemoglobin: 7.4 g/dL). Computed tomography scan showed hemoperitoneum and a gastric mass of uncertain nature. As the patient was hemodynamically stable, a mini-invasive approach was decided. Esophagogastroscopy revealed an umbilicated mass of the posterior gastric wall, therefore allowing for a correct preoperative diagnosis of GIST and its appropriate treatment by laparoscopic atypical gastrectomy. Laparoscopically, a longitudinal resection of gastric fundus including the tumor was performed in a sleeve gastrectomy fashion, 25 minutes after the induction of pneumoperitoneum. The outcome was uneventful. Pathologic examination confirmed a benign 4×3-cm gastric GIST with <1 mitosis per 50 high power field, staining positive for CD117 (C-KIT) and negative for S-100 protein and smooth muscle actin. To our knowledge, it is the first case of a successful laparoscopic resection of an endoscopically diagnosed gastric GIST in an emergency setting. Hemoperitoneum is a rare, potentially severe complication of GIST. As bleeding is rarely severe, most patients may benefit from a mini-invasive approach, even if the tumor is located in the posterior gastric wall

Early stages of formation of the Ag-Ni(111) interface studied by grazing incidence x-ray diffraction and x-ray photoelectron diffraction

Ultra-thin Ag/Ni(111) reconstructed interfaces have been revisited by a combination of in-situ grazing incidence x-ray diffraction (GIXD) and x-ray photoelectron diffraction (XPD) in order to determine the growth mode and to evaluate the interface spacing. Evidence for predominance of single-layer growth in the early stages was obtained through the analysis of the x-ray diffraction rods from the Ag/Ni(111) (root 52 x root 52)R13.9 degrees reconstructed interface, whereas photoelectron diffraction patterns could reveal traces of second-layer Ag scatterers before full wetting of the substrate. Refinement of the atomic coordinates provided by quenched molecular dynamics simulation on the basis of the new x-ray data set enabled us to assess the Ag/Ni average interplanar distance, which was found unexpanded at 2.44 +/- 0.07 angstrom, in contrast with recent determination by low-energy electron diffraction and microscopy. For increasing deposited amounts, both GIXD and XPD showed the expected features of two- and three-layer silver epitaxial overgrowths

From metastability to equilibrium during the sequential growth of Co–Ag supported clusters: a real-time investigation

International audienceAtomic motions and morphological evolution of growing Co–Ag nanoparticles are followed in situ and in real time, by wide and small angle X-ray scattering obtained simultaneously in grazing incidence geometry (GISAXS and GIWAXS), in single or multi-wavelength anomalous modes. The structural analysis of the experimental data is performed with the aid of equilibrium Monte Carlo simulations and of molecular-dynamics simulations of nanoparticle growth. Growth is performed by depositing Co atoms above preformed Ag nanoparticles. This growth procedure is strongly out of equilibrium, because Ag tends to surface segregation, and generates complex growth sequences. The real time analysis of the growth allows to follow the nanoparticle evolution pathways almost atom-by-atom, determining the key mechanisms during Co deposition: starting with the incorporation of Co atoms in sub-surface positions, to the off-center Co domain formation, then by which the nanoparticles finally approach their equilibrium quasi-Janus then core–shell structures

Incoherent Ag islands growth on Ni(100)

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