839 research outputs found

    The CantiClever: a dedicated probe for magnetic force microscopy

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    We present a new cantilever for magnetic-force microscopy (MFM), the CantiClever, which is not derived from atomic-force microscopy (AFM) probes but optimized for MFM. Our design integrates the cantilever and the magnetic tip in a single manufacturing process with the use of silicon micromachining techniques, which allows for batch fabrication of the probes. This manufacturing process enables precise control on all dimensions of the magnetic tip, resulting in a very thin magnetic element with a very high aspect ratio. Using. the CantiClever, magnetic features down to 30 nm could be observed in a CAMST reference sample

    Tungsten trioxide (WO3) as an actuator electrode material for ISFET-based coulometric sensor-actuator systems

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    Acid or base concentrations can be determined by performing an acid-base titration with OH− or H+ ions, coulometrically generated by the electrolysis of water at a noble metal actuator electrode. This can be done very rapidly if the actuator electrode is in close proximity to an ISFET which is used as the indicator electrode to detect the equivalence point in the titration curve. In order to restrict the effect of interfering redox reactions at the actuator electrode during coulometric generation, electroactive actuator materials have been studied which can exchange H+ ions at a lower electrode potential than the potential of anodic water electrolysis. In this paper, electrochemically grown tungsten trioxide (WO3) is proposed as an actuator electrode material. At a WO3 electrode, H+ ions can be generated by a redox reaction at approximately 0.1 V versus SCE in a mildly alkaline solution (0.5–7 mM KOH) (anodic water electrolysis at a Pt electrode occurs at 1.5 V versus SCE). The observed thermodynamic and kinetic behaviour of the redox reaction is in good agreement with the theoretical predictions. Disadvantages of WO3 are its slow dissolution in aqueous solutions and the restriction that a titration at a WO3 electrode can only be performed in alkaline solutions

    Prevalence and correlates of alexithymia in older persons with medically (un)explained physical symptoms

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    Objectives: Much is unknown about the combination of Medically Unexplained Symptoms (MUS) and alexithymia in later life, but it may culminate in a high disease burden for older patients. In the present study we assess the prevalence of alexithymia in older patients with either MUS or Medically Explained Symptoms (MES) and we explore physical, psychological and social correlates of alexithymia.  Methods and Design: A case control study was performed. We recruited older persons (>60 years) with MUS (N = 118) or MES (N = 154) from the general public, general practitioner clinics and hospitals. Alexithymia was measured by the 20-item Toronto Alexithymia Scale, correlates were measured by various questionnaires. Results: Prevalence and severity of alexithymia were higher among older persons with MUS compared to MES. Alexithymia prevalence in the MUS subgroup was 23.7%. We found no association between alexithymia and increasing age. Alexithymia was associated with depressive symptoms, especially in the MUS population. Conclusions: Alexithymia prevalence was lower than generally found in younger patients with somatoform disorder, but comparable to studies with similar diagnostic methods for MUS. Considering the high prevalence and presumed etiological impact of alexithymia in older patients with MUS, as well as its association with depression, this stresses the need to develop better understanding of the associations between alexithymia, MUS and depression in later life

    The surgical anatomy of the superior gluteal nerve and anatomical radiologic bases of the direct lateral approach to the hip

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    In view of the increasing popularity of the direct lateral approach to the hip joint for hemi- or total hip arthroplasty, the location of the superior gluteal nerve (SGN) was studied. This nerve is in danger when using a transgluteal incision. In 20 embalmed specimens the relation of the SGN to the tip of the greater trochanter (TT) was studied as well as the relation to the iliac crest. For this purpose macroscopy, microscopy and CT were used. In 13 hips a so-called most inferior branch was found at an average of 1 cm distal to the inferior branch, the main trunk of the nerve. There was substantial variation in the course of both the inferior and the most inferior branch of the SGN. In order to prevent nerve damage, proximal extension of the transgluteal incision should be limited to 3 cm cranial to TT. Furthermore the incision has to be confined to the distal one third of the distance TT-iliac crest. In tall people extra care should be taken

    Repair of the pronator quadratus after volar plate fixation in distal radius fractures: a systematic review

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    To position the volar plate on the distal radius fracture site, the pronator quadratus muscle needs to be detached from its distal and radial side and lifted for optimal exposure to the fracture site. Although the conventional approach involves repair of the pronator quadratus, controversy surrounds the merits of this repair. The purpose of this study was to compare the functional outcomes of patients with distal radius fractures treated with pronator quadratus repair after volar plate fixation versus no pronator quadratus repair. A systematic search was conducted in Medline, EMBASE and the Cochrane Central Register of Controlled Trials, on 23 July 2015. All studies comparing pronator quadratus repair with no pronator quadratus repair in adult patients undergoing volar plate fixation for distal radius fractures were included. The primary outcome was the Disability of the Arm, Shoulder and Hand (DASH) score at 12 months. Secondary outcomes included range of motion, grip strength, post-operative pain and complications. A total of 169 patients were included, of which 95 underwent pronator quadratus repair, while 74 patients underwent no pronator quadratus repair. At 12 months follow-up no statistically significant differences in DASH-scores and range of motion were observed between pronator quadratus repair and no repair. Moreover, post-operative pain and complication rates were similar between both groups. At 12 months of follow-up, we do not see any advantages of pronator quadratus repair after volar plate fixation in the distal radius. However, a definitive conclusion cannot be drawn from this systematic review due to a lack of available evidence
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