Response to Letter by Dr. Smirmaul Group III/IV muscle afferents contribute to both perception of effort and fatigue

pre-printWe thank Dr. Smirmaul for his interest in our findings, but advise caution not to over-interpret the data to address a question which would have required an entirely different study design. Specifically, the letter to the editor is strongly focused on effort perception, a variable which was, as expected, not considered as a descriptor by the participants when asked to report evoked sensations (Pollak et al., 2014). In fact, given the absence of any sort of muscle contraction or task in our study (i.e. there was no required effort to be rated), an altered effort perception would have been rather unusual

Temperature dependence of electrical characteristics of Pt/GaN Schottky diode fabricated by UHV e-beam evaporation

Temperature-dependent electrical characterization of Pt/n-GaN Schottky barrier diodes prepared by ultra high vacuum evaporation has been done. Analysis has been made to determine the origin of the anomalous temperature dependence of the Schottky barrier height, the ideality factor, and the Richardson constant calculated from the I-V-T characteristics. Variable-temperature Hall effect measurements have been carried out to understand charge transport at low temperature. The modified activation energy plot from the barrier inhomogeneity model has given the value of 32.2 A/(cm(2) K(2)) for the Richardson constant A** in the temperature range 200 to 380 K which is close to the known value of 26.4A/(cm(2) K(2)) for n-type GaN

40 Gb/s PAM-4 transmitter IC for long-wavelength VCSEL links

Conventional 850 nm multimode fiber links deployed in warehouse-scale data centers will be limited by modal dispersion beyond 10 Gb/s when covering distances up to 1 km. This can be resolved by opting for a single-mode fiber (SMF), but typically requires the use of power-hungry edge-emitting lasers. We investigate the feasibility of a high-efficiency SMF link by reporting a 0.13 mu m SiGe BiCMOS laser diode driver optimized for long-wavelength vertical-cavity surface-emitting lasers (VCSELs). Bit-error rate experiments at 28 and 40 Gb/s up to 1 km of SMF reveal that four-level pulse amplitude modulation can compete with non-return-to-zero in terms of energy efficiency and scalability. With 9.4 pJ/b, the presented transmitter paves the way for VCSEL-based SMF links in data centers

Renal AA-amyloidosis in intravenous drug users - a role for HIV-infection?

Background: Chronic renal disease is a serious complication of long-term intravenous drug use (IVDU). Recent reports have postulated a changing pattern of underlying nephropathy over the last decades. Methods: Retrospective investigation including all patients with prior or present IVDU that underwent renal biopsy because of chronic kidney disease between 01.04.2002 and 31.03.2012 in the city of Frankfurt/Main, Germany. Results: Twenty four patients with IVDU underwent renal biopsy because of progressive chronic kidney disease or proteinuria. Renal AA-amyloidosis was the predominant cause of renal failure in 50% of patients. Membranoproliferative glomerulonephritis (GN) was the second most common cause found in 21%. Patients with AA-amyloidosis were more likely to be HIV infected (67 vs.17%; p=0.036) and tended to have a higher rate of repeated systemic infections (92 vs. 50%; p=0.069). Patients with AA-amyloidosis presented with progressive renal disease and nephrotic-range proteinuria but most patients had no peripheral edema or systemic hypertension. Development of proteinuria preceded the decline of GFR for approximately 1--2 years. Conclusions: AA-amyloidosis was the predominant cause of progressive renal disease in the last 10 years in patients with IVDU. The highest rate of AA-amyloidosis observed was seen in HIV infected patients with IVDU. We speculate that chronic HIV-infection as well as the associated immunosuppression might promote development of AA-amyloidosis by increasing frequency and duration of infections acquired by IVDU

Electronic structure and optoelectronic properties of strained InAsSb/GaSb multi quantum wells

A study of the optical properties of a set of InAsxSb1-x/Al0.15In0.85As0.77Sb0.23/GaSb multiple quantum-wells (for x between 0.82 and 0.92) with build-in strains in the -0.62% to +0.05%-range is presented. The energy of the lowest quantum-confined optical transition is calculated by kp perturbation theory and experimentally determined by absorption measurements. Stokes shift of photoluminescence, photocurrent and of the emission from light emitting devices against the absorption edge of the quantum-well are quantified. The impact of the decreasing carrier confinement in the InAsxSb1-x quantum well system with increasing mole fraction is analyzed theoretically, and experimentally demonstrated by photoluminescence measurement. Our results allow for the improvement of optoelectronic devices, in particular for tailoring emission spectra of light emitting diodes