798 research outputs found

    Stability effects on results of diffusion tensor imaging analysis by reduction of the number of gradient directions due to motion artifacts: an application to presymptomatic Huntington's disease.

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    In diffusion tensor imaging (DTI), an improvement in the signal-to-noise ratio (SNR) of the fractional anisotropy (FA) maps can be obtained when the number of recorded gradient directions (GD) is increased. Vice versa, elimination of motion-corrupted or noisy GD leads to a more accurate characterization of the diffusion tensor. We previously suggest a slice-wise method for artifact detection in FA maps. This current study applies this approach to a cohort of 18 premanifest Huntington's disease (pHD) subjects and 23 controls. By 2-D voxelwise statistical comparison of original FA-maps and FA-maps with a reduced number of GD, the effect of eliminating GD that were affected by motion was demonstrated.We present an evaluation metric that allows to test if the computed FA-maps (with a reduced number of GD) still reflect a "true" FA-map, as defined by simulations in the control sample. Furthermore, we investigated if omitting data volumes affected by motion in the pHD cohort could lead to an increased SNR in the resulting FA-maps.A high agreement between original FA maps (with all GD) and corrected FA maps (i.e. without GD corrupted by motion) were observed even for numbers of eliminated GD up to 13. Even in one data set in which 46 GD had to be eliminated, the results showed a moderate agreement

    The chemokine CXCL13 in acute neuroborreliosis

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    Objective Recent studies have suggested an important role of the B cell chemoattractant CXCL13 in acute neuroborreliosis (NB). Our aim was to confirm the diagnostic role of CXCL13 and to evaluate its relevance as a therapy response and disease activity marker in NB. Methods CXCL13 was measured in cerebrospinal fluid (CSF) and serum of patients with NB (n = 28), systemic borreliosis (SB, n = 9), Guillaine-Barre syndrome (GBS, n = 11), Bell's palsy (BP, n = 19), other cranial nerve palsies (CNP, n = 5), cephalgia (C, n = 20), bacterial CNS infections (B-CNS-I, n = 16) and viral CNS infections (V-CNS-I, n = 18). For follow-up studies, serial sample pairs were evaluated from 25 patients with NB (n = 56), 11 with B-CNS-I (n = 25) and 14 with V-CNS-I (n = 36). Results CSF-CXCL13 was significantly elevated in NB compared with other neurological diseases (p<0.001). Using receiver operating characteristic analysis, 337 ng/g was determined as a cut-off with a sensitivity of 96.4% and a specificity of 96.9%. Of all the parameters investigated, CSF CXCL13 showed the fastest response to antibiotic therapy, decreasing significantly (p = 0.008) within 1 week. In untreated patients, CSF CXCL13 was elevated in patients with a short duration of disease. Borrelia burgdorferi antibody index showed no significant (p = 0.356) change over follow-up. Conclusions The study confirms the relevance of CXCL13 as a diagnostic biomarker of NB and suggests that CSF CXCL13 in NB is linked to duration of disease and could be a marker of disease activity and response to antibiotic therapy

    Motor expertise facilitates the accuracy of state extrapolation in perception

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    Ludolph N, Plöger J, Giese MA, Ilg W. Motor expertise facilitates the accuracy of state extrapolation in perception. PLOS ONE. 2017;12(11): e0187666

    Fatal anaphylactic sting reaction in a patient with mastocytosis

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    We report on a 33-year-old female patient with indolent systemic mastocytosis and urticaria pigmentosa who died of an anaphylactic reaction after a yellow jacket sting. As she had no history of previous anaphylactic sting reaction, there was no testing performed in order to detect hymenoptera venom sensitization. But even if a sensitization had been diagnosed, no venom immunotherapy (VIT) would have been recommended. It is almost certain that VIT would have saved her life and it is most likely that VIT is indicated in some patients with mastocytosis with no history of anaphylactic sting reaction. However, no criteria have been established in order to allow a selection of mastocytosis patients eligible for such a `prophylactic' VIT. Copyright (C) 2008 S. Karger AG, Basel

    Совершенствование поведенческой модели лидера в организации

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    Объектом исследования являются Топ 100 российских и зарубежных компаний. Цель работы – определение характеристик лидера в организации. В результате исследования были раскрыты характеристики лидера, проанализированы его поведение, оценены теоретические аспекты на примере организаций, усовершенствована современная модель лидера в организации.The object of the study are the Top 100 Russian and foreign companies. Goal – to determine characteristics of a leader in the organization. The study revealed the characteristics of a leader, analyzed its behavior, the estimated theoretical aspects on the example of organizations, developed the modern model of the leader of the organization

    Pattern of paresis in ALS is consistent with the physiology of the corticomotoneuronal projections to different muscle groups

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    OBJECTIVE: A recent neuroanatomical staging scheme of amyotrophic lateral sclerosis (ALS) indicates that a cortical lesion may spread, as a network disorder, both at the cortical level and via corticofugal tracts, including corticospinal projections providing direct monosynaptic input to α-motoneurons. These projections are involved preferentially and early in ALS. If these findings are clinically relevant, the pattern of paresis in ALS should primarily involve those muscle groups that receive the strongest direct corticomotoneuronal (CM) innervation. METHODS: In a large cohort (N=436), we analysed retrospectively the pattern of muscle paresis in patients with ALS using the UK Medical Research Council (MRC) scoring system; we subsequently carried out two independent prospective studies in two smaller groups (N=92 and N=54). RESULTS: The results indicated that a characteristic pattern of paresis exists. When pairs of muscle groups were compared within patients, the group known to receive the more pronounced CM connections was significantly weaker. Within patients, there was greater relative weakness (lower MRC score) in thumb abductors versus elbow extensors, for hand extensors versus hand flexors and for elbow flexors versus elbow extensors. In the lower limb, knee flexors were relatively weaker than extensors, and plantar extensors were weaker than plantar flexors. CONCLUSIONS: These findings were mostly significant (p<0.01) for all six pairs of muscles tested and provide indirect support for the concept that ALS may specifically affect muscle groups with strong CM connections. This specific pattern could help to refine clinical and electrophysiological ALS diagnostic criteria and complement prospective clinicopathological correlation studies

    CSF Concentrations of cAMP and cGMP Are Lower in Patients with Creutzfeldt-Jakob Disease but Not Parkinson's Disease and Amyotrophic Lateral Sclerosis

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    The cyclic nucleotides cyclic adenosine-3',5'-monophosphate (cAMP) and cyclic guanosine-3',5'-monophosphate (cGMP) are important second messengers and are potential biomarkers for Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Creutzfeldt-Jakob disease (CJD). Here, we investigated by liquid chromatography/tandem mass spectrometry (LC-MS/MS) the cerebrospinal fluid (CSF) concentrations of cAMP and cGMP of 82 patients and evaluated their diagnostic potency as biomarkers. For comparison with a well-accepted biomarker, we measured tau concentrations in CSF of CJD and control patients. CJD patients (n = 15) had lower cAMP (-70%) and cGMP (-55%) concentrations in CSF compared with controls (n = 11). There was no difference in PD, PD dementia (PDD) and ALS cases. Receiver operating characteristic (ROC) curve analyses confirmed cAMP and cGMP as valuable diagnostic markers for CJD indicated by the area under the curve (AUC) of 0.86 (cAMP) and 0.85 (cGMP). We calculated a sensitivity of 100% and specificity of 64% for cAMP and a sensitivity of 67% and specificity of 100% for cGMP. The combination of both nucleotides increased the sensitivity to 80% and specificity to 91% for the term cAMPxcGMP (AUC 0.92) and to 93% and 100% for the ratio tau/cAMP (AUC 0.99). We conclude that the CSF determination of cAMP and cGMP may easily be included in the diagnosis of CJD and could be helpful in monitoring disease progression as well as in therapy control

    Комплексные наземные геофизические исследования с целью поисков золотого оруденения на флангах Раздолинской площади (Красноярский край)

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    Данный проект состоит из следующих частей: общей, проектной, специальной, технико-экономической. Общая часть содержит сведения о географическом положении, климатических особенностях, геологических особенностях проектируемого участка. В проектной части производится выбор объекта исследования, комплекса для проведения работ. Рассматриваются: методика и техника проведения геофизических исследований, методика интерпретации геофизических данных. В специальной части рассматривается метод электроразведки МПП. Технико-экономическая часть включает главы, которые отражают организационно-экономические вопросы проведения геофизических работ, расчет и обоснование стоимости проекта, а также применяемые мероприятия по обеспечению экологической устойчивости и безопасности жизнедеятельности.This project consists of the following parts: General, project, special, technical and economic. The General part contains information about the geographical location, climatic features, geological features of the structure Sulfides. In the design part is the choice of the object of study, the complex for work. Methods and techniques of geophysical research, methods of interpretation of geophysical data are considered. In a special part the method of electrical prospecting of MPP is considered. The technical and economic part includes chapters that reflect the organizational and economic issues of geophysical works, calculation and justification of the project cost, as well as the measures used to ensure environmental sustainability and safety

    Onset of dissipation in ballistic atomic wires

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    Electronic transport at finite voltages in free-standing gold atomic chains of up to 7 atoms in length is studied at low temperatures using a scanning tunneling microscope (STM). The conductance vs voltage curves show that transport in these single-mode ballistic atomic wires is non-dissipative up to a finite voltage threshold of the order of several mV. The onset of dissipation and resistance within the wire corresponds to the excitation of the atomic vibrations by the electrons traversing the wire and is very sensitive to strain.Comment: Revtex4, 4 pages, 3 fig
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