668 research outputs found

    P300 in Schizophrenia: Interactions between Amplitudes and Topography

    Get PDF
    Low P300 amplitudes and topographical asymmetries have been reponed in schizophrenic patients, but reference-independent amplitude assessment failed to replicate reduced amplitudes. P300 amplitude is conventially assessed at midline electrodes (PZ), anti asymmetric topography as reported in schizophrenics, may conj'ound this measurement. We lnvestigated the possible Interaction between P300 ropography and assessments of amplitudes. ln 41 clinically stable schizophrenics and 31 normal controls, the generalfinding ofreduced amplitudes at the P'l electrode and topographical asymmetrles in the patient group were replicated. ln both groups, a.symmetries of the P300 field (lateralized peaks) reduced the standard amplitude assessment at the midline parletal electrode, but did not Qjfoct the reference-independent, global amplitude assessment. This shows thal asymmetry per se does not imply reduced field strength. in addition, in schizophreraics. but not in controls, there was a significcmt effect oftlae direction of asymmetry on both amplltude measures, amplitudes belng lower with increasing shift ofthe P300 peak to the right side. Considering also the slightly left-lateralized peaks in the normal controls. this suggests rhat only right lateralized P300 peaks upressfunctional deficits in schizophrenics, whereas left lateralized pealcs fall wlthin the physiological variability of the P3OO field. Tht refonnce-independent amplitude assessment is proposed for unambiguous amplitude assessment in order to better define the clinical, psychological and physiopathological mtaning of the P3OO alterations in schizophrenics

    Tight-Binding model for semiconductor nanostructures

    Full text link
    An empirical scpa3s_cp^3_a tight-binding (TB) model is applied to the investigation of electronic states in semiconductor quantum dots. A basis set of three pp-orbitals at the anions and one ss-orbital at the cations is chosen. Matrix elements up to the second nearest neighbors and the spin-orbit coupling are included in our TB-model. The parametrization is chosen so that the effective masses, the spin-orbit-splitting and the gap energy of the bulk CdSe and ZnSe are reproduced. Within this reduced scpa3s_cp_a^3 TB-basis the valence (p-) bands are excellently reproduced and the conduction (s-) band is well reproduced close to the Γ\Gamma-point, i.e. near to the band gap. In terms of this model much larger systems can be described than within a (more realistic) sp3s∗sp^3s^*-basis. The quantum dot is modelled by using the (bulk) TB-parameters for the particular material at those sites occupied by atoms of this material. Within this TB-model we study pyramidal-shaped CdSe quantum dots embedded in a ZnSe matrix and free spherical CdSe quantum dots (nanocrystals). Strain-effects are included by using an appropriate model strain field. Within the TB-model, the strain-effects can be artifically switched off to investigate the infuence of strain on the bound electronic states and, in particular, their spatial orientation. The theoretical results for spherical nanocrystals are compared with data from tunneling spectroscopy and optical experiments. Furthermore the influence of the spin-orbit coupling is investigated

    Yours ever (well, maybe): Studies and signposts in letter writing

    Get PDF
    Electronic mail and other digital communications technologies seemingly threaten to end the era of handwritten and typed letters, now affectionately seen as part of snail mail. In this essay, I analyze a group of popular and scholarly studies about letter writing-including examples of pundits critiquing the use of e-mail, etiquette manuals advising why the handwritten letter still possesses value, historians and literary scholars studying the role of letters in the past and what it tells us about our present attitudes about digital communications technologies, and futurists predicting how we will function as personal archivists maintaining every document including e-mail. These are useful guideposts for archivists, providing both a sense of the present and the past in the role, value and nature of letters and their successors. They also provide insights into how such documents should be studied, expanding our gaze beyond the particular letters, to the tools used to create them and the traditions dictating their form and function. We also can discern a role for archivists, both for contributing to the literature about documents and in using these studies and commentaries, suggesting not a new disciplinary realm but opportunities for new interdisciplinary work. Examining a documentary form makes us more sensitive to both the innovations and traditions as it shifts from the analog to the digital; we can learn not to be caught up in hysteria or nostalgia about one form over another and archivists can learn about what they might expect in their labors to document society and its institutions. At one time, paper was part of an innovative technology, with roles very similar to the Internet and e-mail today. It may be that the shifts are far less revolutionary than is often assumed. Reading such works also suggests, finally, that archivists ought to rethink how they view their own knowledge and how it is constructed and used. © 2010 Springer Science+Business Media B.V

    Molecular imaging in multiple myeloma — novel PET radiotracers improve patient management and guide therapy

    Get PDF
    Due to its proven value in imaging of multiple myeloma (MM), including staging, prognostication, and assessment of therapy response, 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET) is utilized extensively in the clinic. However, its accuracy is hampered by imperfect sensitivity (e.g., so-called FDG-negative MM) as well as specificity (e.g., inflammatory processes), with common pitfalls including fractures and degenerative changes. Novel approaches providing a read-out of increased protein or lipid membrane syntheses, such as [11C]methionine and [11C]choline or the C-X-C motif chemokine receptor 4-targeting radiotracer [68Ga]Pentixafor, have already been shown to be suitable adjuncts or alternatives to FDG. In the present focused review, those imaging agents along with their theranostic potential in the context of MM are highlighted

    Changes in Walking Spatiotemporal Parameters After Therapeutic Yoga in People with Chronic Stroke

    Get PDF
    Walking limitations after stroke can contribute to long-term functional impairments. Walking characteristics such as spatiotemporal step parameters may be associated with these persistent walking limitations. The purpose of this study was to investigate changes in specific spatiotemporal walking parameters such as: walking speed; step length; swing time; step parameter symmetry; and double support time in adults with stroke who were participating in a therapeutic yoga intervention. The therapeutic yoga intervention was offered as a post-rehabilitation wellness activity 2 times per week for 8 weeks and was led by a yoga therapist. Spatiotemporal walking data were collected using the GAITRite Walkway System on a sub sample (n=24) of participants in a randomized controlled trial testing the efficacy of therapeutic yoga for improving balance in adults with chronic stroke. These data demonstrated that therapeutic yoga may have a positive impact on some spatiotemporal walking characteristics such as comfortable walking speed, step length, and double support time, while other spatiotemporal walking characteristics did not change (step parameter symmetry) or change at a significant level (sustained walking speed). The clinical relevance of this study is that participation in therapeutic yoga as a post-rehabilitation wellness activity may have a positive impact on walking characteristics in adults with chronic stroke

    In-vivo somatostatin-receptor expression in small cell lung cancer as a prognostic image biomarker and therapeutic target

    Get PDF
    Background: Given the dismal prognosis of small cell lung cancer (SCLC), novel therapeutic targets are urgently needed. We aimed to evaluate whether SSTR expression, as assessed by positron emission tomography (PET), can be applied as a prognostic image biomarker and determined subjects eligible for peptide receptor radionuclide therapy (PRRT). Methods: A total of 67 patients (26 females; age, 41–80 years) with advanced SCLC underwent SSTR-directed PET/computed tomography (somatostatin receptor imaging, SRI). SRI-avid tumor burden was quantified by maximum standardized uptake values (SUVmax) and tumor-to-liver ratios (T/L) of the most intense SCLC lesion. Scan findings were correlated with progression-free (PFS) and overall survival (OS). In addition, subjects eligible for SSTR-directed radioligand therapy were identified, and treatment outcome and toxicity profile were recorded. Results: On a patient basis, 36/67 (53.7%) subjects presented with mainly SSTR-positive SCLC lesions (>50% lesions positive); in 10/67 patients (14.9%), all lesions were positive. The median SUVmax was found to be 8.5, while the median T/L was 1.12. SRI-uptake was not associated with PFS or OS, respectively (SUVmax vs. PFS, ρ = 0.13 with p = 0.30 and vs. OS, ρ = 0.00 with p = 0.97; T/L vs. PFS, ρ = 0.07 with p = 0.58 and vs. OS, ρ = −0.05 with p = 0.70). PRRT was performed in 14 patients. One patient succumbed to treatment-independent infectious complications immediately after PRRT. In the remaining 13 subjects, disease control was achieved in 5/13 (38.5%) with a single patient achieving a partial response (stable disease in the remainder). In the sub-group of responding patients, PFS and OS were 357 days and 480 days, respectively. Conclusions: SSTR expression as detected by SRI is not predictive of outcome in patients with advanced SCLC. However, it might serve as a therapeutic target in selected patient

    Scanning Transmission X-ray Microscopy with X-ray Fluorescence Detection at the XUV Beamline P04, PETRA III, DESY

    Get PDF
    The presented scanning transmission x-ray microscope (STXM), build on top of our existing modular platform (FlexIX) for high resolution imaging experiments, allows versatile investigations of different samples. The FlexIX endstation allows to switch between a Full Field and a STXM mode. For the STXM mode we use a spatialy resolved detector together with an energy dispersive detector, this allows to investigate the morphology and the chemical or elemental distribution of the sample simultaneous. The combination of the nanoscopy endstation and the XUV beamline P04 results in a powerful tool for investigations of life science samples.BMBF, 05K13UL1, Verbundprojekt 05K2013 - Hochauflösende Bildgebung: Hochauflösende Bildgebung im EUV- und weichen Röntgenbereich bei PETRA III und FLASH. Teilprojekt 1

    Yoga after Stroke Leads to Multiple Physical Improvements

    Get PDF
    poster abstractMethods: Forty-seven individuals with chronic stroke were recruited and randomized 3:1 to yoga or waitlist control (usual care). The yoga group completed one hour yoga sessions twice a week for 8 weeks. Yoga was taught by a yoga therapist and included modified physical postures in seated, standing, and supine positions and included yoga breathing, bilateral movements, concluding with relaxation. Assessments before and after the 8 weeks included: flexibility via passive range of motion (PROM) for the hamstrings (HS) and active range of motion (AROM) for hip flexion, cervical rotation, and cervical lateral flexion; strength with the chair to stand and arm curl and hip flexion manual muscle test; and walking capacity with the 6 minute walk test. We compared groups with a t-test/Mann Whitney. We used paired t-tests/Wilcoxon non-parametric tests to compare baseline and 8-week data

    Characterization of a New Mouse Model for Peripheral T Cell Lymphoma in Humans

    Get PDF
    Peripheral T cell lymphomas (PTCLs) are associated with a poor prognosis due to often advanced disease at the time of diagnosis and due to a lack of efficient therapeutic options. Therefore, appropriate animal models of PTCL are vital to improve clinical management of this disease. Here, we describe a monoclonal CD8+ CD4− αÎČ T cell receptor VÎČ2+ CD28+ T cell lymphoma line, termed T8-28. T8-28 cells were isolated from an un-manipulated adult BALB/c mouse housed under standard pathogen-free conditions. T8-28 cells induced terminal malignancy upon adoptive transfer into syngeneic BALB/c mice. Despite intracellular expression of the cytotoxic T cell differentiation marker granzyme B, T8-28 cells appeared to be defective with respect to cytotoxic activity as read-out in vitro. Among the protocols tested, only addition of interleukin 2 in vitro could partially compensate for the in vivo micro-milieu in promoting growth of the T8-28 lymphoma cells
    • 

    corecore