Electrical observation of a tunable band gap in bilayer graphene nanoribbons at room temperature

We investigate the transport properties of double-gated bilayer graphene nanoribbons at room temperature. The devices were fabricated using conventional CMOS-compatible processes. By analyzing the dependence of the resistance at the charge neutrality point as a function of the electric field applied perpendicular to the graphene surface, we show that a band gap in the density of states opens, reaching an effective value of ~sim50 meV. This demonstrates the potential of bilayer graphene as FET channel material in a conventional CMOS environment.Comment: 3 pages, 3 figure

The Alzheimer variant of Lewy body disease: A pathologically confirmed case-control study

The objective of the study was to identify clinical features that distinguish patients with dementia with Lewy bodies (DLB), who were classified as Alzheimer's disease ( AD) patients, from patients with AD. We examined a group of 27 patients from our memory clinic, originally diagnosed with AD, of whom 6 were postmortem found to have DLB. For the present study, we compared cognitive, noncognitive and neurological symptoms between the two groups. We found that there were no differences on ratings of dementia and scales for activities of daily living. Patients with DLB performed better on the MMSE and the memory subtest of the CAMCOG, but there was no difference in any other cognitive domain. Furthermore, genetic risk factors, including family history of dementia or allele frequency of the apolipoprotein epsilon 4, did not discriminate between the two groups, and there were no differences on CCT scans. Taken together, our findings suggest that Lewy body pathology may be present in patients who do not show the typical clinical features which distinguish DLB from AD. Copyright (C) 2005 S. Karger AG, Basel

RELIABILITY OF DROP JUMP VARIATIONS IN PERFORMANCE DIAGNOSTICS

In several sports athletes have to produce maximal power for accelerating the body and/or sport equipment (e.g. long jump, shot putt, basketball, etc.). The primary indicator used for estimating power output in drop jumps are the peak force rate (Fex) and the peak force (Fmax). These variables also characterise the reactive force ability of an athlete during a stretch-shortening-cycle (SSC). In order to use the accumulated energy produced in the eccentric phase during the concentric contraction, the contact please revise must not be longer than 200 ms (Komi 1984). Reactive force abilities are commonly tested in drop jumps (DJ). The accomplishment of DJ is variously described in the literature, so no standardized conditions are given (Baca 1999). One corresponding aspect is the arm position (free arm-swing vs. arms akimbo). Particularly, jumps with arm-swing require a higher grade of coordination (e.g. basketball) and are associated with an enhanced jump height. DJs with arms akimbo are often used in subjects with less sports experience or if the performance diagnostics primarily focuses on the power output in isolated leg extensions. Another aspect is the method of calculating the jump height from the measured force data. The calculation of the jump height from the momentum (based on the force-time-curve) might be inaccurate as the exact drop height is not known. Consequently, the jump height often is calculated from the flight time. This method, however, is also inaccurate if the landing position differs substantially from the take-off position. This problem might be solved performing a consecutive double DJ. Thus, the aim of the study is to investigate different DJ variations with respect to reliability

LATERALITY IN VERTICAL JUMPS

Laterality is a widely investigated phenomenon in motor activities. Various studies deal with the functional dominance of one limb or one side of the body in sports (e.g. Fischer, 1988, Oberbeck, 1989). One common method for the identification of lateral differences in the lower limbs is the single-leg vertical jump (e.g. Stephens, 2005). In order to reduce the risk of injury and the coordinative demand Impellizzeri et al. (2007) and Newton et al. (2006) proposed a double-leg vertical jump force test for the assessment of bilateral strength asymmetry. The focus of these studies was set on the strength imbalance between the right and left leg using the maximum force as the relevant factor. Further parameters to describe lateral differences were neglected and still little is known about the coherence between laterality and jumping performance. Therefore, the aim of this study was to investigate laterality in established double-leg vertical jumps in performance diagnostics, such as the counter movement jump (CMJ), squat jump (SJ) and drop jump (DJ)

Modeling of primary dendrite arm spacing variations in thin-slab casting of low carbon and low alloy steels

Solidification structure of a High Strength Low Alloy (HSLA) steel, in terms of dendrite arm spacing distribution across the shell thickness, is studied in a breakout shell from a thin-slab caster at Tata Steel in IJmuiden. Columnar dendrites were found to be the predominant morphology throughout the shell with size variations across the shell thickness. Primary Dendrite Arm Spacing (PDAS) increases by increasing the distance from meniscus or slab surface. Subsequently, a model is proposed to describe the variation of the PDAS with the shell thickness (the distance from slab surface) under solidifiction conditions experienced in the primary cooling zone of thin-slab casting. The proposed relationship related the PDAS to the shell thickness and, hence, can be used as a tool for predicting solidifcation structure and optimizing the thin-slab casting of low alloy steels

The effect of anterior cruciate ligament recontruction on lower extremity relative phase dynamics during walking and running

The purpose of this investigation was to use relative phase dynamics to evaluate gait in individuals with a reconstructed anterior cruciate ligament (ACL) during walking and running. Relative phase dynamics can describe the coordination strategies between the interacting segments at the lower extremity. Ten subjects who had undergone ACL reconstruction using the central third of their patellar tendon and ten healthy controls walked and ran on a treadmill at a self-selected pace. Relative phase dynamics were calculated for the foot–shank and shank–thigh coordinative relation- ships. Statistical differences between the groups were noted for the foot– shank relationship (p\u3c0.05) during both walking and running and for the shank–thigh relationship (p\u3c0.05) during walking. Our results indicate that current ACL reconstructive techniques may result in altered relative phase dynamics. These changes in relative phase dynamics could be related to a loss of sensory information about joint position and velocity that is typically provided by the intact ACL. Additionally, relative phase adaptations could be a learned response from the early stages of postsurgical rehabilitation. Relative phase dynamics provide quantitative information about the dynamic status of the ACL-reconstructed knee that cannot be gained from the conventional time-series evaluation of gait analysis data. Relative phase dynamics measures should supplement the conventional gait analysis measures that are used today for the clinical evaluation of the functional dynamic stability of the reconstructed knee. The examination of relative phase dynamics could be clinically important for the quantification of new ACL surgical interventions and of patient performance at various stages of rehabilitation. Further research should incorporate relative phase dynamics to understand the influence of ACL reconstruction on coordination and functional patient outcomes

Time-resolved broadband analysis of slow-light propagation and superluminal transmission of electromagnetic waves in three-dimensional photonic crystals

A time-resolved analysis of the amplitude and phase of THz pulses propagating through three-dimensional photonic crystals is presented. Single-cycle pulses of THz radiation allow measurements over a wide frequency range, spanning more than an octave below, at and above the bandgap of strongly dispersive photonic crystals. Transmission data provide evidence for slow group velocities at the photonic band edges and for superluminal transmission at frequencies in the gap. Our experimental results are in good agreement with finite-difference-time-domain simulations.Comment: 7 pages, 11 figure

Inelastic interaction mean free path of negative pions in tungsten

The inelastic interaction mean free paths lambda of 5, 10, and 15 GeV/c pions were measured by determining the distribution of first interaction locations in a modular tungsten-scintillator ionization spectrometer. In addition to commonly used interaction signatures of a few (2-5) particles in two or three consecutive modules, a chi2 distribution is used to calculate the probability that the first interaction occurred at a specific depth in the spectrometer. This latter technique seems to be more reliable than use of the simpler criteria. No significant dependence of lambda on energy was observed. In tungsten, lambda for pions is 206 plus or minus 6 g/sq cm

Photodynamische Therapie bei altersbedingter Makuladegeneration am schlechteren und besseren Auge

Zusammenfassung: Hintergrund: Die PDT ist die Standardbehandlung vieler Formen der exsudativen bzw. neovaskulären Makuladegeneration (AMD). Trotz Therapie fällt die Sehschärfe häufig in den Low-vision-Bereich ab. Die Kosteneffizienz der Therapie am schlechteren Auge wird daher kontrovers diskutiert. Patienten und Methoden: Retrospektive Fallkontrollstudie aller Patienten, welche zwischen September 1999 und November 2004 am Universitätsspital Zürich eine PDT erhalten haben. Die Situation bei Präsentation und der Verlauf unter Therapie wurden bei ersten (schlechteren) und zweiten (besseren) Augen verglichen. Ergebnisse: In 117/228Fällen (51,3%) war der Visus am behandelten Auge bei Präsentation besser (oder gleich) als der Visus am Partnerauge. Der Visus vor Behandlung betrug bei den besseren Augen im Mittel 0,58±0,27logMAR [Snellen: 0,26 (0,14-0,49)] und 0,69±0,4logMAR [Snellen 0,20 (0,08-0,51)] bei den schlechteren Augen (p=0,015). Nach Behandlung bestand zwischen den Gruppen weder bezüglich Visus bzw. Visusveränderung noch bezüglich Membrangröße bzw. Größenveränderung der Membran ein signifikanter Unterschied. Schlussfolgerung: Die Resultate nach PDT sind beim zweiten (bzw. besseren) Auge nicht signifikant besser als beim ersten (bzw. schlechteren) Aug