Five-year follow-up of a randomized clinical trial comparing open surgery, foam sclerotherapy and endovenous laser ablation for great saphenous varicose veins

Background: New treatment methods have challenged open surgery as a treatment for great saphenous vein (GSV) insufficiency, the most common being ultrasound-guided foam sclerotherapy (UGFS) and endovenous laser ablation (EVLA). This study evaluated the long-term results of surgery, EVLA and UGFS in the treatment of GSV reflux. Methods: Patients with symptomatic GSV reflux were randomized to undergo either open surgery, EVLA or UGFS. The main outcome measure was the occlusion rate of the GSV at 5years after operation. Results: The study included 196 patients treated during 2008-2010; of these, 166 (847 per cent) participated in the 5-year follow-up. At 5years, the GSV occlusion rate was 96 (95 per cent c.i. 91 to 100) per cent in the open surgery group, 89 (82 to 98) per cent after EVLA and 51 (38 to 64) per cent after UGFS (P Conclusion: UGFS has significantly inferior occlusion rates compared with open surgery or EVLA, and results in additional treatments.Peer reviewe

Influence of V/III molar ratio on the formation of In vacancies in InN grown by metal-organic vapor-phase epitaxy

We have applied a slow positron beam to study InN samples grown by metal-organic vapor-phase epitaxy with different V/III molar ratios (3300–24 000) and at different growth temperatures (550–625°C). Indium vacancies were identified in samples grown at V/III ratios below 4000. Their concentration is in the 10exp17cm−3 range. No strong dependence of vacancy concentration on the molar ratio was observed. At low V/III ratios, however, In droplets and vacancy clusters are formed near the substrate interface. The elevated growth temperature enhances the In vacancy formation, possibly due to limited sticking of In on the growth surface close to the decomposition temperature.Peer reviewe

Longitudinal Validity and Minimal Important Change for the Modified Lower Extremity Functional Scale (LEFS) in Orthopedic Foot and Ankle Patients

The lower extremity functional scale (LEFS) is a patient-reported outcome measure for lower extremity disorders. Aim of this study was to assess the longitudinal validity including responsiveness and test-retest reliability of the revised 15-item version, and to define the minimal important change (MIC) of the modified LEFS in a generic sample of orthopedic foot and ankle patients who underwent surgery. Responsiveness, effect size, and standardized response mean were measured by determining the score change between the baseline and 6 months administration of the LEFS from 156 patients. There was no significant difference between preoperative (median 78, interquartile range [IQR] 64.2-90.3) and postoperative (median 75.0, IQR 61.7-95.0) scores. Both effect size and standardized response mean were low (0.06 and 0.06, respectively). Test-retest reliability of the LEFS was satisfactory. Intraclass correlation coefficient was 0.85 (95% confidence interval 0.81-0.88). MIC value could not be estimated due to the lack of significant score change. The modified LEFS presented with relatively low longitudinal validity in a cohort of generic orthopedic foot and ankle patients. The findings of this study indicate that the modified LEFS might not be the optimal instrument in assessing the clinical change over time for these patients. (c) 2021 The Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)Peer reviewe

Prolonged injury symptoms and later visits to psychiatric care after mild traumatic brain injury in school-age

Objective To investigate demographic and pre-injury factors in Finnish school-aged children admitted to pediatric neurology services after mild traumatic brain injury (mTBI). The relation of these factors to prolonged injury symptoms and later visits into psychiatric care was assessed. Methods Demographic information, pre-injury learning status, and neuropsychological test results of 120 patients aged 7-16 years were retrospectively collected from the hospital medical records. Data were compared with self- or parent-reported injury symptoms at 1-3 months post-injury and later visits to psychiatric care. Results According to medical records, 14.2% of the children with mTBI had a diagnosed neurobehavioral or psychiatric condition pre-injury. Additionally, 53.3% of the children had some neurobehavioral or psychiatric concerns or traits prior to the injury. Over half (56.7%) of the children studied were symptomatic at 1-3 months following the injury. Female gender and presence of prolonged symptoms were predictive for later visit into psychiatric care. Conclusions Pre-injury neurobehavioral or psychiatric problems may predict prolonged injury symptoms following pediatric mTBI. In this retrospective patient series, prolonged symptoms and female gender seem to predict the need for later psychiatric care. Monitoring the recovery of children with mTBI and pre-injury risk factors is important for timely interventions.Peer reviewe

Influence of silicon doping on vacancies and optical properties of AlxGa1-xN thin films

The authors have used positron annihilation spectroscopy and photoluminescence measurements to study the influence of silicon doping on vacancy formation in AlGaN:Si structures. The results show a correlation between the Doppler broadening measurements and the intensity from 510nm photoluminescence transition. The reduction in the W parameter when the [Si]∕[Al+Ga] fraction in the gas phase is above 3×10exp−4 indicates that the positrons annihilate in an environment where less Ga 3d electrons are present, i.e., they are trapped in group-III vacancies. The observation of vacancies at these silicon concentrations coincides with the onset of the photoluminescence transition at 510 nm.Peer reviewe

Clustering of vacancy defects in high-purity semi-insulating SiC

Positron lifetime spectroscopy was used to study native vacancy defects in semi-insulating silicon carbide. The material is shown to contain (i) vacancy clusters consisting of 4--5 missing atoms and (ii) Si vacancy related negatively charged defects. The total open volume bound to the clusters anticorrelates with the electrical resistivity both in as-grown and annealed material. Our results suggest that Si vacancy related complexes compensate electrically the as-grown material, but migrate to increase the size of the clusters during annealing, leading to loss of resistivity.Comment: 8 pages, 5 figure

Fluence, flux, and implantation temperature dependence of ion-implantation-induced defect production in 4H–SiC

Vacancy-type defect production in Al- and Si-implanted 4H–SiC has been studied as a function of ion fluence, ion flux, and implantation temperature in the projected ion range region by positron annihilation spectroscopy and Rutherford backscattering techniques. Ion channeling measurements show that the concentration of displaced silicon atoms increases rapidly with increasing ion fluence. In the ion fluence interval of 10¹³–10¹⁴cm¯² the positron annihilation parameters are roughly constant at a defect level tentatively associated with the divacancy VCVSi. Above the ion fluence of 10¹⁴cm¯² larger vacancy clusters are formed. For implantations as a function of ion flux (cm¯²s¯¹), ion channeling and positron annihilation measurements behave similarly, i.e., indicating increasing damage in the projected range region with increasing ion flux. However, for samples implanted at different temperatures the positron annihilation parameter S shows a clear minimum at approximately 100°C, whereas the normalized backscattering yield decrease continuously with increasing implantation temperature. This is explained by the formation of larger vacancy clusters when the implantation temperature is increased.This work has been supported partly by the Nordic Academy for Education and Research Training (NorFa) and the Swedish Foundation for International cooperation in Research and Higher Education (STINT)