"(Diphosphine)Nickel"-catalyzed negishi cross-coupling: an experimental and theoretical study.

The use of a strongly donating "(bis-dialkylphosphine)Ni" fragment promotes the catalytic coupling of a large range of ArCl and ArZnCl derivatives under mild conditions. Stoichiometric mechanistic investigations and DFT calculations prove that a Ni(0) /Ni(II) cycle is operative in this system.

Analysis of Digital Competence for Spanish Teachers at Pre-University Educational Key Stages during COVID-19.

Over time, the role of information and communication technologies (ICT) has become increasingly important in most areas of our lives, including education. So much so, that during the COVID-19 pandemic, the use of these tools has been essential to continue the teaching process. One of the great challenges facing teachers today is their need to adapt to this new educational scenario by acquiring the necessary digital skills. The aim of this study is to determine the level of competence of teaching in pre-university education key stages. To this end, a questionnaire was distributed among education centres and teachers in the Autonomous Community of Extremadura, obtaining 109 valid responses. The analysis methodology was the formation of clusters using the K-means model. The results confirmed that the teachers perceived a medium-high level of knowledge and use of ICT. Moreover, that this digital competence is conditioned by factors such as age, experience, gender, and level of education. In conclusion, public administrations are encouraged to facilitate teachers' knowledge and application of ICT according to the profiles identified.

Tantalum is a good bone graft substitute in tibial tubercle advancement.

BACKGROUND: Porous tantalum is reportedly a good substitute for structural bone graft in several applications. So far, its use has not been reported in tibial tuberosity anteriorization (TTA) for treatment of isolated degenerative chondral lesions of the patellofemoral joint. QUESTIONS/PURPOSES: We asked whether the use of this material would produce similar standardized functional scores, pain (VAS), fusion rates, complications, and patient satisfaction to those for bone graft. PATIENTS AND METHODS: We performed a randomized, controlled trial in 101 patients (108 knees) scheduled for TTA comparing a porous tantalum implant (57 knees) with an autologous local tibial bone graft (51 knees). The minimum followup was 5 years (mean, 6.2 years; range, 5-8 years). RESULTS: At the last followup, clinical scores, fusion rates, and maintenance of the anteriorization either were better or similar for the TTA using the tantalum implant depending on the respective parameter. The operative technique was easier and shorter with the tantalum device. Complication and failure rates were greater using bone graft. Patient satisfaction was greater using the tantalum implant. CONCLUSIONS: Porous tantalum provided a reasonable alternative to bone graft in TTA. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Revision of failed total hip arthroplasty acetabular cups to porous tantalum components: a 5-year follow-up study.

We reviewed 263 consecutive patients with failed acetabular components after total hip arthroplasty that were revised using porous tantalum acetabular components and augments when necessary. The mean follow-up was 73.6 months (range, 60-84 months). The improvement of mean Harris hip score, Western Ontario and McMaster Osteoarthritis Index, and University of California Los Angeles activity scales were statistically significant (P < .001). Subjective assessments showed that 87.3% of patients reported "improvement" and 85.9% were "very or fairly pleased" with the results. At the most recent follow-up, all acetabular components were radiographically stable and none required rerevision for loosening. The acetabular revision was considered successful in 87% of cases. From this study, we conclude that the acetabular component used was reliable in creating a durable composite without failure for a minimum of 5 years.

Anterior cervical fusion with tantalum implant: a prospective randomized controlled study.

STUDY DESIGN: A prospective randomized controlled study was carried out. OBJECTIVE: To determine the effectiveness and safety of a tantalum implant in achieving anterior cervical fusion following 1-level discectomy as treatment of degenerative cervical disc disease with radiculopathy. SUMMARY OF BACKGROUND DATA: The gold standard for the treatment of degenerative cervical disc disease could not be already identified. The morbidity of autologous graft and plating, and the doubt about the mechanical efficacy of plate fixation and the clinical benefits in 1-level fusion have promoted the use of other constructs. METHODS: Sixty-one patients were randomized to anterior cervical discectomy and fusion with interbody implant of tantalum (n = 28) or by means of autologous iliac bone graft and plating (n = 33). Fusion rate and segmental height and alignment were blind assessed by radiographs by 2 independent reviewers. Clinical status was evaluated using pain visual analogue scale, the Neck Disability Index, and the Zung Depression Scale. Patient's subjective satisfaction was recorded. Complications and operative parameters were also taken into account. RESULTS: With an endpoint of 24 months, radiologic and clinical outcomes were similar for both treatments without significant difference. The safety of fusion with tantalum implant was obvious, based on the analysis of complications. Complication rate was considerably higher for the autologous graft plus plating procedure than for implant tantalum (P < 0.005). CONCLUSION: The efficacy to achieve fusion after 1-level anterior cervical discectomy, with a good radiologic and clinical outcome, using tantalum implant is equivalent to that of autologous graft and anterior plate, being safer as avoids donor-site graft harvesting and plating complications.

Granuloma anular elastolítico a células gigantes / Giant cell elastolytic annular granuloma

Se presenta un caso de granuloma elastolítico a células gigantes, dermatosis recién individualizada y con características clínicas e histopatológicas bién definidas