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The physics of the superconducting state in two-dimensional (2D) electron systems is relevant to understanding the high-transition-temperature copper oxide superconductors and for the development of future superconductors based on interface electron systems (1). But it is not yet understood how fundamental superconducting parameters, such as the spectral density of states, change when these superconducting electron systems are depleted of charge carriers. Here we use tunnel spectroscopy with planar junctions to measure the behaviour of the electronic spectral density of states as a function of carrier density, clarifying this issue experimentally. We chose the conducting LaAl[O.sub.3]SrTi[O.sub.3]interface (2) as the 2D superconductor, because this electron system can be tuned continuously with an electric gate field (3). We observed an energy gap of the order of 40 microelectronvolts in the density of states, whose shape is well described by the Bardeen-Cooper-Schrieffer superconducting gap function. In contrast to the dome-shaped dependence of the critical temperature, the gap increases with charge carrier depletion in both the underdoped region and the overdoped region. These results are analogous to the pseudogap behaviour of the high-transition-temperature copper oxide superconductors and imply that the smooth continuation of the superconducting gap into pseudogap-like behaviour could be a general property of 2D superconductivity., One of the main challenges in understanding the superconductivity of copper oxide superconductors is to identify the origin and nature of the pseudogap phase in the underdoped regime (4,5). This [...]

Single crystalline YBa2Cu3O7-δ (YBCO) thin films were grown by pulsed laser deposition in order to probe the oxygen deficiency δ using a mono-energetic positron beam. The sample set covered a large range of δ (0.191<δ<0.791) yielding a variation of the critical temperature T c between 25 and 90K. We found a linear correlation between the Doppler broadening of the positron electron annihilation line and δ determined by X-ray diffraction. Ab-initio calculations have been performed in order to exclude the presence of Y vacancies and to ensure the negligible influence of potentially present Ba or Cu vacancies to the found correlation. Moreover, scanning with the positron beam allowed us to analyze the spatial variation of δ, which was found to fluctuate with a standard deviation of up to 0.079(5) within a single YBCO film. [ABSTRACT FROM AUTHOR]

Using the metal-insulator transition that takes place as a function of carrier density at the LaAlO3–SrTiO3 interface, oxide diodes have been fabricated with room-temperature breakdown voltages of up to 200 V. With applied voltage, the capacitance of the diodes changes by a factor of 150. The diodes are robust and operate at temperatures up to 270 C. [ABSTRACT FROM AUTHOR]

With ellipsometry, x-ray diffraction, and resistance measurements we investigated the electric-field effect on the confined electrons at the LaAlO3/SrTiO3 interface. We obtained evidence that the localization of the electrons at negative gate voltage is induced, or at least enhanced, by a polar phase transition in SrTiO3 which strongly reduces the lattice polarizability and the subsequent screening. In particular, we show that the charge localization and the polar order of SrTiO3 both develop below ~50 K and exhibit similar, unipolar hysteresis loops as a function of the gate voltage. [ABSTRACT FROM AUTHOR]

Phase-sensitive, spatially resolved optical second-harmonic-generation experiments were performed on LaAlO3/SrTiO3 heterostructures. Lateral inhomogeneities on a length scale of ≈ 30 μm are found when a one-unit-cell-thick epitaxial monolayer of LaAIO3 is grown on TiO2-terminated SrTiO3 single crystals. The inhomogeneity is absent in samples with LaAlO33 layers of more than one unit cell. The results are discussed in the framework of electronic, oxidic, and chemical inhomogeneities. [ABSTRACT FROM AUTHOR]

Electromyography (EMG) proves invaluable myoelectric manifestation in identifying neuromuscular alterations resulting from ischemic strokes, serving as a potential marker for diagnostics of gait impairments caused by ischemia. This study aims to develop an interpretable machine learning (ML) framework capable of distinguishing between the myoelectric patterns of stroke patients and those of healthy individuals through Explainable Artificial Intelligence (XAI) techniques. The research included 48 stroke patients (average age 70.6 years, 65% male) undergoing treatment at a rehabilitation center, alongside 75 healthy adults (average age 76.3 years, 32% male) as the control group. EMG signals were recorded from wearable devices positioned on the bicep femoris and lateral gastrocnemius muscles of both lower limbs during indoor ground walking in a gait laboratory. Boosting ML techniques were deployed to identify stroke-related gait impairments using EMG gait features. Furthermore, we employed XAI techniques, such as Shapley Additive Explanations (SHAP), Local Interpretable Model-Agnostic Explanations (LIME), and Anchors to interpret the role of EMG variables in the stroke-prediction models. Among the ML models assessed, the GBoost model demonstrated the highest classification performance (AUROC: 0.94) during cross-validation with the training dataset, and it also overperformed (AUROC: 0.92, accuracy: 85.26%) when evaluated using the testing EMG dataset. Through SHAP and LIME analyses, the study identified that EMG spectral features contributing to distinguishing the stroke group from the control group were associated with the right bicep femoris and lateral gastrocnemius muscles. This interpretable EMG-based stroke prediction model holds promise as an objective tool for predicting post-stroke gait impairments. Its potential application could greatly assist in managing post-stroke rehabilitation by providing reliable EMG biomarkers and address potential gait impairment in individuals recovering from ischemic stroke.

Electroencephalography (EEG) is a non-invasive method employed to discern human behaviors by monitoring the neurological responses during cognitive and motor tasks. Machine learning (ML) represents a promising tool for the recognition of human activities (HAR), and eXplainable artificial intelligence (XAI) can elucidate the role of EEG features in ML-based HAR models. The primary objective of this investigation is to investigate the feasibility of an EEG-based ML model for categorizing everyday activities, such as resting, motor, and cognitive tasks, and interpreting models clinically through XAI techniques to explicate the EEG features that contribute the most to different HAR states. The study involved an examination of 75 healthy individuals with no prior diagnosis of neurological disorders. EEG recordings were obtained during the resting state, as well as two motor control states (walking and working tasks), and a cognition state (reading task). Electrodes were placed in specific regions of the brain, including the frontal, central, temporal, and occipital lobes (Fz, C1, C2, T7, T8, Oz). Several ML models were trained using EEG data for activity recognition and LIME (Local Interpretable Model-Agnostic Explanations) was employed for interpreting clinically the most influential EEG spectral features in HAR models. The classification results of the HAR models, particularly the Random Forest and Gradient Boosting models, demonstrated outstanding performances in distinguishing the analyzed human activities. The ML models exhibited alignment with EEG spectral bands in the recognition of human activity, a finding supported by the XAI explanations. To sum up, incorporating eXplainable Artificial Intelligence (XAI) into Human Activity Recognition (HAR) studies may improve activity monitoring for patient recovery, motor imagery, the healthcare metaverse, and clinical virtual reality settings.

Electroencephalography (EEG) is immediate and sensitive to neurological changes resulting from sleep stages and is considered a computing tool for understanding the association between neurological outcomes and sleep stages. EEG is expected to be an efficient approach for sleep stage prediction outside a highly equipped clinical setting compared with multimodal physiological signal-based polysomnography. This study aims to quantify the neurological EEG-biomarkers and predict five-class sleep stages using sleep EEG data. We investigated the three-channel EEG sleep recordings of 154 individuals (mean age of 53.8 ± 15.4 years) from the Haaglanden Medisch Centrum (HMC, The Hague, The Netherlands) open-access public dataset of PhysioNet. The power of fast-wave alpha, beta, and gamma rhythms decreases; and the power of slow-wave delta and theta oscillations gradually increases as sleep becomes deeper. Delta wave power ratios (DAR, DTR, and DTABR) may be considered biomarkers for their characteristics of attenuation in NREM sleep and subsequent increase in REM sleep. The overall accuracy of the C5.0, Neural Network, and CHAID machine-learning models are 91%, 89%, and 84%, respectively, for multi-class classification of the sleep stages. The EEG-based sleep stage prediction approach is expected to be utilized in a wearable sleep monitoring system.

Purpose: Long-term impact of stage-adapted field reduction in a large cohort of gastric marginal zone lymphoma (gMZL) patients treated conservatively with curative radiation therapy (RT)., Patients and Methods: Prospective analysis of paper records of 290 patients with stage IE-IIE gMZL, treated in 78 radiotherapeutic institutions in Germany from 1992-2013. Stage-adapted radiation fields decreased from extended field (EF) to involved field (IF) over the course of three consecutive prospective trials of the German Study Group on Gastrointestinal Lymphoma (DSGL). Treatment results were compared between the three cohorts., Results: Overall collective with median age of 60 years, slight male predominance (m:f = 1.1:1) and ratio of disease stage I:stage II = 2.1:1. Median follow-up 6.4 years in total: 13.0 years in the first gastrointestinal study (GIT 1992), 8.2 years in the second (GIT 1996) and 4.7 years in the third study (DSGL 01/2003). Stage-adapted radiation field decrease together with further technological development led to reduced relative frequencies of acute/chronic adverse effects and until now was accompanied by lower disease recurrence. The third study design with smallest field size (IF in stage I, locoregional EF in stage II) achieved the best survival outcome at the 5‑year follow-up (overall survival 92.7%, event-free survival 89.5% and lymphoma-specific survival 100.0%). Disease relapse observed in 10 patients. Cumulative incidence of disease-specific death was 1.7% of the followed patients. Primary disease stage associated with lymphoma-specific survival., Conclusion: Stage-adapted reduction towards IF in gMZL resulted in favorable adverse effects, local control and survival rates. These results support further decreases in modern RT of gMZL.

Purpose: To describe the technique of an all-arthroscopic Eden-Hybinette procedure in the revision setting for treatment of a failed instability procedure, particularly after failed Latarjet, as well as to present preliminary results of this technique., Methods: Between 2007 and 2011, 18 shoulders with persistent instability after failed instability surgery were treated with an arthroscopic Eden-Hybinette technique using an autologous bicortical iliac crest bone graft. Of 18 patients, 12 (9 men, 3 women) were available for follow-up. The average follow-up was 28.8 months (range, 15 to 60 months). A Latarjet procedure was performed as an index surgery in 10 patients (83%). Two patients (17%) had a prior arthroscopic Bankart repair., Results: Eight patients (67%) obtained a good or excellent result, whereas 4 patients (33%) reported a fair or poor result. Seven patients (58%) returned to sport activities. A positive apprehension test persisted in 5 patients (42%), including 2 patients (17%) with recurrent subluxations. The Rowe score increased from 30.00 to 78.33 points (P < .0001). The Walch-Duplay score increased from 11.67 to 76.67 points (P < .0001). The Western Ontario Shoulder Instability Index score showed a good result of 28.71% (603 points). The average anterior flexion was 176° (range, 150° to 180°), and the average external rotation was 66° (range, 0° to 90°). Two patients (16.67%) showed a progression of glenohumeral osteoarthritic changes, with each patient increasing by one stage in the Samilson-Prieto classification. All 4 patients (33%) with a fair or poor result had a nonunion identified on postoperative computed tomography scan., Conclusions: An all-arthroscopic Eden-Hybinette procedure in the revision setting for failed instability surgery, although technically demanding, is a safe, effective, and reproducible technique. Although the learning curve is considerable, this procedure offers all the advantages of arthroscopic surgery and allows reconstruction of glenoid defects and restoration of shoulder stability in this challenging patient population. In our hands, this procedure yields good or excellent results in 67% of patients. Successful outcome is correlated with bony healing of the iliac crest graft to the glenoid., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Studies suggest that around 20% of adults in Europe experience chronic pain, which not only has a considerable impact on their quality of life but also imposes a substantial economic burden on society. More than one-third of these people feel that their pain is inadequately managed. A range of analgesic drugs is currently available, but recent guidelines recommend that NSAIDs and COX-2 inhibitors should be prescribed cautiously. Although the short-term efficacy of opioids is good, adverse events are common and doses are frequently limited by tolerability problems. There is a perceived need for improved pharmacological treatment options. Currently, many treatment decisions are based solely on pain intensity. However, chronic pain is multifactorial and this apaproach ignores the fact that different causative mechanisms may be involved. The presence of more than one causative mechanism means that chronic pain can seldom be controlled by a single agent. Therefore, combining drugs with different analgesic actions increases the probability of interrupting the pain signal, but is often associated with an increased risk of drug/drug interactions, low compliance and increased side effects. Tapentadol combines μ-opioid receptor agonism and noradrenaline reuptake inhibition in a single molecule, with both mechanisms contributing to its analgesic effects. Preclinical testing has shown that μ-opioid agonism is primarily responsible for analgesia in acute pain, whereas noradrenaline reuptake inhibition is more important in chronic pain. In clinical trials in patients with chronic pain, the efficacy of tapentadol was similar to that of oxycodone, but it produced significantly fewer gastrointestinal side-effects and treatment discontinuations. Pain relief remained stable throughout a 1-year safety study. Thus, tapentadol could possibly overcome some of the limitations of currently available analgesics for the treatment of chronic pain., (© 2011 The Authors. Pain Practice © 2011 World Institute of Pain.)

Postoperative irradiation of the operative field is an established method to prevent heterotopic ossification in total hip arthroplasty. In this study two theoretical dose-equivalent regimens of radiation therapy were compared. Allogenic bone matrix was implanted in both thighs of 50 adult male Wistar rats to induce heterotopic ossification. Immediately after operation the implants of 40 animals were irradiated using a single-dose of 7 Gy or 5 fractions of 2 Gy each. Ten rats served as a controlgroup and did not undergo irradiation. Radiation therapy with 5 x 2 Gy led to a highly significantly better suppression of heterotopic ossification than irradiation with 1 x 7 Gy (p < 0.001; paired-t-test). Single-dose irradiation reduced the mean calcium contents to 138.87 +/- 22.84 micrograms Ca2+/mg implanted bone matrix; fractionated irradiation obtained a reduction to 63.35 +/- 21.16 micrograms Ca2+/mg implanted bone matrix. In thigh implants not exposed to irradiation the mean calcium content was 191.50 +/- 11.46 micrograms Ca2+/mg implanted bone matrix. Radiographically better suppression of bone formation could be documented after irradiation with 5 x 2 Gy compared to 1 x 7 Gy and non-irradiated implants. The histological aspect of the explanted specimens showed quantitatively more new bone formation in the non-irradiated controls than in both irradiation groups. In view of experimentally demonstrated better effects, as well as the reduced side effects, fractionated irradiation appears preferable.

97 patients were treated with cementless custom-made total hip replacement of the Aldinger type for osteoarthritis of the hip. All were prophylactically treated by radiotherapy with 5 x 2 Gy. 10.3% showed heterotopic ossification. 8 patients showed ossification grade I by the Arcq scale and 2 of grade II. Clinical results according to the Merle d'Aubigné score were good or very good in over 90% at one year postoperatively. One patient showed loosening of the femoral stem caused by sinking-in of the custom-made implant. During the revision procedure there were no signs of radiation induced damage to the implant bed. Negative sequelae to the bony implant bed by prophylactic radiotherapy cannot be detected on radiological assessment. Side effects like delayed wound healing or alteration of local immune status with subsequent infection which are commonly discussed, were not seen. Fractionated irradiation is an effective means of prophylaxis of heterotopic ossification.

Periarticular ossification is one of the main problems of total hip replacement. Irradiation with megavolt photons is known to be a well recognized means of prevention of heterotopic ossification. So far only little scientific basis exists about the most favourable way of radiotherapy for prevention of ectopic ossification. In this study two theoretically equivalent doses are compared. Allogeneic bone matrix was implanted into both thighs of 50 adult male Wistar rats for experimental induction of heterotopic ossification. Immediately after operation the thigh implants were irradiated with a single dose of 7 Gy or a total dose of 10 Gy given in 5 fractions of 2 Gy each. In the model of matrix-induced osteogenesis in rats fractionated irradiation by 5 x 2 Gy leaded to a highly-significant (p = 0.001) better suppression of ectopic ossification compared to irradiation by 1 x 7 Gy. Once-only irradiation with 1 x 7 Gy leads to a reduction of the calcium contents by 27.5%, split irradiation by 5 x 2 Gy obtained a reduction by 66.9% compared to the calcium contents of thigh implants not exposed to radiation. In view of experimentally proven better effects, fractionated irradiation has to be preferred to single dose radiation also considering less side effects in split radiation.

In the Department of Radiotherapy, University of Tübingen, dose specification is performed according to the new ICRU recommendations since June, 1991. The purpose was to prescribe, record and report photon beam therapy in a consistent way applicable to most clinical situations and to provide uniform criteria for a comparison of treatment results from different radiotherapy centers. For "level 2" plans (including CT planning), the concept of dose specification has been changed to the "ICRU reference point" instead of to form the isodose encompassing the target volume as we did previously. A total of 24 representative treatment plans have been analyzed to assess the consequences of this change on dose prescription, treatment technique, and the size of the irradiated volume. Our results revealed that the prescription of single and total doses have to be individually adjusted according to the specific treatment plans. ICRU recommendations on dose homogeneity may significantly affect treatment technique and field sizes. Small deviations in dose prescription may be of particular influence on late responding normal tissues ("double trouble" due to simultaneous adjustment of single and total doses). Detailed comparisons of individual treatment plans with respect to physical, biological, and clinical data are obviously necessary in order to make sure that the outcome of a radiation treatment is not deviating too much from the clinical experience based on the former dose specification concept.

Ten patients underwent Syme amputation for diabetic peripheral vascular disease between 1980 and 1986 and were observed postoperatively for an average of 5 years. Surgical wounds healed in only five of the 10 patients; they were then fitted for a permanent Syme's prosthesis. All failures resulted from the inability to heal the surgical incisions primarily. The clinical records of these patients were retrospectively analyzed for predictors of successful clinical outcome. The ischemic index, grade of the lesion, initial wound treatment, and presence of the infection at the time of amputation were not found to be reliable predictors of a successful level of amputation. Clinical assessment of both the vascular and nutritional status of the patient was necessary to predict a successful result at this level of amputation.