Six Classes of Diffraction-Based Optoelectronic Instruments

Six classes of diffraction-based optoelectronic instruments have been invented as means for wavelength-based processing of light. One family of anticipated applications lies in scientific instrumentation for studying chemical and physical reactions that affect and/or are affected differently by light of different wavelengths or different combinations of wavelengths. Another family of anticipated applications lies in optoelectronic communication systems

Piezoelectric Diffraction-Based Optical Switches

Piezoelectric diffraction-based optoelectronic devices have been invented to satisfy requirements for switching signals quickly among alternative optical paths in optical communication networks. These devices are capable of operating with switching times as short as microseconds or even nanoseconds in some cases

Validation of quantitative scores derived from motor evoked potentials in the assessment of primary progressive multiple sclerosis: a longitudinal study

Objective:; To evaluate the sensitivity to change of differently calculated quantitative scores from motor evoked potentials (MEP) in patients with primary progressive multiple sclerosis (PPMS).; Methods:; Twenty patients with PPMS had MEP to upper and lower limbs at baseline, years 1 and 2 measured in addition to clinical assessment [Expanded Disability Status Scale (EDSS), ambulation score]; a subsample (; n; = 9) had a nine-hole peg test (NHPT) and a timed 25-foot walk (T25FW). Quantitative MEP scores for upper limbs (qMEP-UL), lower limbs (qMEP-LL), and all limbs (qMEP) were calculated in three different ways, based on; z; -transformed central motor conduction time (CMCT), shortest corticomuscular latency (CxM-sh), and mean CxM (CxM-mn). Changes in clinical measures and qMEP metrics were analyzed by repeated-measures analysis of variance (rANOVA), and a factor analysis was performed on change in qMEP metrics.; Results:; Expanded Disability Status Scale and ambulation score progressed in the rANOVA model (; p; < 0.05;; post-hoc; comparison baseline-year 2,; p; < 0.1). Lower limb and combined qMEP scores showed significant deterioration of latency (; p; < 0.01, MEP-LL_CxM-sh:; p; < 0.05) and in; post-hoc; comparisons (baseline-year 2,; p; < 0.05), qMEP_CxM-mn even over 1 year (; p; < 0.05). Effect sizes were higher for qMEP scores than for clinical measures, and slightly but consistently higher when based on CxM-mn compared to CxM-sh or CMCT. Subgroup analysis yielded no indication of higher sensitivity of timed clinical measures over qMEP scores. Two independent factors were detected, the first mainly associated with qMEP-LL, the second with qMEP-UL, explaining 65 and 29% of total variability, respectively.; Conclusions:; Deterioration in qMEP scores occurs earlier than EDSS progression in patients with PPMS. Upper and lower limb qMEP scores contribute independently to measuring change, and qMEP scores based on mean CxM are advantageous. The capability to detect subclinical changes longitudinally is a unique property of EP and complementary to clinical assessment. These features underline the role of EP as candidate biomarkers to measure effects of therapeutic interventions in PPMS

Intramedullary screw fixation in proximal fifth-metatarsal fractures in sports: clinical and biomechanical analysis

Introduction and purpose: Intramedullary screw fixation (ISF) of proximal fifth-metatarsal fractures is known as first treatment option in young, sports active patients. No study analyzed functional and biomechanical outcome before. Hypothetically ISF leads to (1) a high bony union rate within 12weeks, (2) normal hindfoot eversion strength, and (3) normal gait and plantar pressure distribution. Methods: Fourteen out of 22 patients were available for follow-up with an average follow-up of 42months; clinical and radiological follow-up, and biomechanical evaluation by isometric muscular strength measurement (inversion, eversion strength) and dynamic pedobarography, comparing to the non-affected contralateral foot. Level of significance: 0.05. Results: Subjective result: Excellent or good result in 14 patients, none fair or poor. AOFAS midfoot score: 100 points in 13 patients and 87 points in 1 patient. The same sports activity level (0-4) was reached in 13 out of 14 patients. Radiologic examination: consolidation after 6weeks in 9 patients and after 12weeks in another 4 patients, one partial union. Average maximal eversion strength 59N (ratio to the contralateral foot: 0.92, not significant). Dynamic pedobarography showed ratios of 0.99-1.01 to the contralateral side for ground reaction force, ground peak time, peak pressure and contact area (not significant). Interpretation: A very-high patient-satisfaction, a fast bony healing and complete return to sports were documented. Muscular strength measurement and dynamic pedobarography showed complete functional rehabilitation. Therefore, ISF in proximal fifth-metatarsal fractures can be recommended as a secure procedur

Non-substitutional single-atom defects in the Ge_(1-x)Sn_x alloy

Ge_(1-x)Sn_x alloys have proved difficult to form at large x, contrary to what happens with other group IV semiconductor combinations. However, at low x they are typical examples of well-behaved substitutional compounds, which is desirable for harnessing the electronic properties of narrow band semiconductors. In this paper, we propose the appearance of another kind of single-site defect ($\beta-Sn$), consisting of a single Sn atom in the center of a Ge divacancy, that may account for these facts. Accordingly, we examine the electronic and structural properties of these alloys by performing extensive numerical ab-initio calculations around local defects. The results show that the environment of the $\beta$ defect relaxes towards a cubic octahedral configuration, facilitating the nucleation of metallic white tin and its segregation, as found in amorphous samples. Using the information stemming from these local defect calculations, we built a simple statistical model to investigate at which concentration these $\beta$ defects can be formed in thermal equilibrium. These results agree remarkably well with experimental findings, concerning the critical concentration above which the homogeneous alloys cannot be formed at room temperature. Our model also predicts the observed fact that at lower temperature the critical concentration increases. We also performed single site effective-field calculations of the electronic structure, which further support our hypothesis.Comment: 12 pages, 1 table, 16 figure

EEG: a helpful tool in the prediction of psychosis

Objective: EEG investigation in patients with an at risk mental state (ARMS) for psychosis and patients with a first episode of psychosis (FE) in comparison to healthy controls (HC) in a clinical follow up study of Early Detection of Psychosis. Method: Seventy-three patients (42 ARMS, 31 FE) and 35 HC were investigated. ARMS patients were followed up in order to monitor transition to psychosis. Psychopathology was assessed with respect to positive and negative symptoms. At study baseline EEG was recorded using the 10/20 system. Two blinded neurologists analyzed the EEGs visually for presence of generalized or focal slowing and epileptiform discharges. EEG data were controlled for medication and substance abuse. For statistical analyses we used χ2-tests, logistic regression, ANOVA, and receiver operating characteristics. Results: Patients showed significantly more pathological EEG abnormalities than HC (P<0.05), located more frequently in temporal or fronto-temporal regions (P<0.01) of the brain, with twice as many pathologies in ARMS than in FE patients. The specificity of the prediction of psychosis could be increased from 59 to 73% by considering EEG pathology in addition to psychopathology alone. In contrast, sensitivity of prediction remained unchanged. Conclusions: These results show that EEG investigation in patients at risk for psychosis can add to the identification of those patients who will not develop psychosis later o

Aberrant Current Source-Density and Lagged Phase Synchronization of Neural Oscillations as Markers for Emerging Psychosis

Background: Converging evidence indicates that neural oscillations coordinate activity across brain areas, a process which is seemingly perturbed in schizophrenia. In particular, beta (13-30 Hz) and gamma (30-50 Hz) oscillations were repeatedly found to be disturbed in schizophrenia and linked to clinical symptoms. However, it remains unknown whether abnormalities in current source density (CSD) and lagged phase synchronization of oscillations across distributed regions of the brain already occur in patients with an at-risk mental state (ARMS) for psychosis. Methods: To further elucidate this issue, we assessed resting-state EEG data of 63 ARMS patients and 29 healthy controls (HC). Twenty-three ARMS patients later made a transition to psychosis (ARMS-T) and 40 did not (ARMS-NT). CSD and lagged phase synchronization of neural oscillations across brain areas were assessed using eLORETA and their relationships to neurocognitive deficits and clinical symptoms were analyzed using linear mixed-effects models. Results: ARMS-T patients showed higher gamma activity in the medial prefrontal cortex compared to HC, which was associated with abstract reasoning abilities in ARMS-T. Furthermore, in ARMS-T patients lagged phase synchronization of beta oscillations decreased more over Euclidian distance compared to ARMS-NT and HC. Finally, this steep spatial decrease of phase synchronicity was most pronounced in ARMS-T patients with high positive and negative symptoms scores. Conclusions: These results indicate that patients who will later make the transition to psychosis are characterized by impairments in localized and synchronized neural oscillations providing new insights into the pathophysiological mechanisms of schizophrenic psychoses and may be used to improve the prediction of psychosi