2,307 research outputs found

    Tai2Cl2, eine neue Verbindung vom MX4-Typ (M=Nb, Ta; X=C1, Br, I)

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    The new compound TaI2Cl2 is formed from the reaction of TaCl5 with Tal5 and Ta powder in sealed Ta containers at 450 °C. The crystal structure contains quasi one-dimensional chains of TaI4/2Cl2 octahedra, sharing opposite edges (orthorhombic, Immm, a = 831.5(5) pm, b = 993.7(4) pm, c = 748.5(4) pm; R = 0.037 for 297 independent intensities). Each chain has two Ta bridging iodine bonds alternating in length along the chain direction yielding short (314.9(2) pm) and long (433.6(3) pm) Ta-Ta distances. The electronic structure indicates a Peierls-type stabilization

    Neue Niob- und Tantalchloride der Zusammensetzung A4 [M6Cl18] (A = (Ga,) In, TI; M = Nb, Ta)

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    The syntheses of new compounds of the general formula A4[Nb6Cl18] (A = Ga, In, Tl) and A4[Ta6Cl18] (A = In, Tl) are reported. The indexing of their X-ray powder patterns was performed isotypically with K4Nb6Cl18]- A single-crystal structure refinement on In4[Ta6Cl18] gave the space group C2/m, Z - 2, a = 1077.7(3) pm, b = 1542.3(5) pm, c = 960.2(2) pm, β = 117.68(2) . The structure contains [Ta6Cl12Cl6]4- ions linked via I+ ions . In+ is situated in a strongly distorted coordination sphere of Cl-

    Initial Development and Reliability of a Motivation for Weight Loss Scale

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    Objective: We aimed at developing and evaluating a questionnaire assessing health and appearance as the two main reasons for weight loss in overweight and obese individuals. Methods: Using data from two representative telephone surveys in Switzerland, the factorial structure of this questionnaire was analyzed by exploratory and confirmatory factor analysis. The model obtained was cross-validated with data from a second representative Swiss survey and multigroup analyses according to sex, age, BMI and regional language subgroups were performed. Results: This lead to a 24-item, 3-factor solution, with factors labeled ‘health’, ‘appearance in relation to others’, and ‘appearance in relation to oneself’. Internal consistency and test-retest reliability were good. Conclusions: To the best of our knowledge, this is the first validated questionnaire assessing overweight and obese individuals’ reasons for weight loss. It should be further tested whether using this questionnaire as a pretreatment assessment device will help in tailoring treatments to individuals, thereby increasing treatment adherence and success

    Having versus not having social interactions in patients diagnosed with depression or social phobia and controls

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    Humans need meaningful social interactions, but little is known about the consequences of not having them. We examined meaningful social interactions and the lack thereof in patients diagnosed with major depressive disorder (MDD) or social phobia (SP) and compared them to a control group (CG). Using event-sampling methodology, we sampled participants' everyday social behavior 6 times per day for 1 week in participants' natural environment. We investigated the quality and the proportion of meaningful social interactions (when they had meaningful social interactions) and degree of wishing for and avoidance of meaningful social interactions (when they did not have meaningful social interactions). Groups differed on the quality and avoidance of meaningful social interactions: Participants with MDD and SP reported perceiving their meaningful social interactions as lower quality (in terms of subjective meaningfulness) than the CG, with SP patients reporting even lower quality than the MDD patients. Further, both MDD and SP patients reported avoiding meaningful social interactions significantly more often than the CG. Although the proportion of meaningful social interactions was similar in all groups, the subjective quality of meaningful social interactions was perceived to be lower in MDD and SP patients. Future research might further identify what variables influenced the reinforcement of the MDD and SP patients so that they engaged in the same number of meaningful social interactions even though the quality of their meaningful social interactions was lower. Increasing awareness of what happens when patients do or do not have meaningful social interactions will help elucidate a potentially exacerbating or maintaining factor of the disorders

    Orientation dependence of thermal and mechanical hysteresis in Ni51Fe18Ga27Co4 single crystals

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    The orientation dependence of thermal ΔТ and mechanical Δσ hysteresis was investigated in Ni51Fe18Ga27Co4 single crystals as-grown with isobaric (shape memory effect) and isothermal (superelasticity) experiments. Single crystals oriented along the [001]-direction show a high reversible deformation of 001 ЭПФ ε = (4,0 ± 0,2) % for martensitic transformations, small thermal hysteresis ΔТ = (22 ± 2) K and mechanical Δσ001 = (47 ± 2) МПа hysteresis, as compared with to single crystals oriented along the [110]-direction. Such orientation dependence is determined by the contribution of the L10-martensite under the εdetw in deformation of transformation

    A TNF-α Promoter Polymorphism Is Associated with Juvenile Onset Psoriasis and Psoriatic Arthritis

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    Tumor necrosis factor-α is considered to be one of the important mediators in the pathogenesis of psoriasis. A strong association of juvenile onset psoriasis with the major histocompatibility complex encoded HLA-Cw6 antigen has been reported but it is unclear whether Cw6 itself or a closely linked gene is involved in the pathogenesis. This study has focused on the association of promoter polymorphisms of the major histocompatibility complex encoded tumor necrosis factor-α gene with psoriasis and psoriatic arthritis. Tumor necrosis factor-α promoter polymorphisms were sought by sequence-specific oligonucleotide hybridization and by direct sequencing in Caucasian patients with juvenile onset psoriasis and with psoriatic arthritis and in healthy controls. A mutation at position −238 of the tumor necrosis factor-α promoter was present in 23 of 60 patients (38%; p < 0.0001; Pcorr < 0.008) with juvenile onset psoriasis and in 20 of 62 patients (32%; p < 0.0003; Pcorr < 0.03) with psoriatic arthritis, compared with seven of 99 (7%) Caucasian controls. There was a marked increase of homozygotes for this mutation in the psoriasis group. Another mutation at position −308 was found in similar proportions of patients and controls. Our study shows a strong association of the tumor necrosis factor-α promoter polymorphism at position −238 with psoriasis and psoriatic arthritis. Our findings suggest that this promoter polymorphism itself or a gene in linkage disequilibrium with tumor necrosis factor-α predispose to the development of psoriasis

    On Measuring Non-Recursive Trade-Offs

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    We investigate the phenomenon of non-recursive trade-offs between descriptional systems in an abstract fashion. We aim at categorizing non-recursive trade-offs by bounds on their growth rate, and show how to deduce such bounds in general. We also identify criteria which, in the spirit of abstract language theory, allow us to deduce non-recursive tradeoffs from effective closure properties of language families on the one hand, and differences in the decidability status of basic decision problems on the other. We develop a qualitative classification of non-recursive trade-offs in order to obtain a better understanding of this very fundamental behaviour of descriptional systems

    Social interaction in Major Depression Disorder, Social Phobia, and Controls: The importance of Affect

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    Social interactions are crucial to human beings. As technology advances, new possibilities of interaction emerge, bringing both opportunities and risks, especially when interpersonal behaviors are impaired (e.g., depression) or associated with strong fear (e.g., social phobia). The authors investigated whether technological social interactions (i.e., phone and internet/chat) are used equally as often as face-to-face social interactions in participants with mental disorders and in controls and whether differences are associated with unpleasant emotions, that is, whether the association between negative affect (NA) or positive affect (PA) differed by type of social interaction. The self-chosen social interactions of participants diagnosed with major depressive disorder (MDD) or social phobia (SP) were compared with participants without these diagnoses (control group, CG). Using event sampling methodology (ESM), participants’ everyday social behavior was sampled six times per day for one week in their natural environment. The CG engaged more often in face-to-face social interactions, while participants diagnosed with MDD or SP engaged more often in phone social interactions. Across all groups, there was a positive relationship between NA and the frequency of technological social interactions, and a positive relationship between PA and the frequency of face-to-face social interactions. The propensity to experience higher levels of PA during face-to-face social interactions and NA during technological social interactions is important to consider when selecting and planning social interactions. Clinicians may consider exploring the social interaction patterns of their patients in the light of these findings. Likewise, developers of technological interventions and clinicians using them should consider the potential that technological social interactions may increase NA

    Microscopic multifrequency MR elastography for mapping viscoelasticity in zebrafish

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    Purpose: The zebrafish (Danio rerio) has become an important animal model in a wide range of biomedical research disciplines. Growing awareness of the role of biomechanical properties in tumor progression and neuronal development has led to an increasing interest in the noninvasive mapping of the viscoelastic properties of zebrafish by elastography methods applicable to bulky and nontranslucent tissues. Methods: Microscopic multifrequency MR elastography is introduced for mapping shear wave speed (SWS) and loss angle (φ) as markers of stiffness and viscosity of muscle, brain, and neuroblastoma tumors in postmortem zebrafish with 60 µm in-plane resolution. Experiments were performed in a 7 Tesla MR scanner at 1, 1.2, and 1.4 kHz driving frequencies. Results: Detailed zebrafish viscoelasticity maps revealed that the midbrain region (SWS = 3.1 ± 0.7 m/s, φ = 1.2 ± 0.3 radian [rad]) was stiffer and less viscous than telencephalon (SWS = 2.6 ± 0. 5 m/s, φ = 1.4 ± 0.2 rad) and optic tectum (SWS = 2.6 ± 0.5 m/s, φ = 1.3 ± 0.4 rad), whereas the cerebellum (SWS = 2.9 ± 0.6 m/s, φ = 0.9 ± 0.4 rad) was stiffer but less viscous than both (all p < .05). Overall, brain tissue (SWS = 2.9 ± 0.4 m/s, φ = 1.2 ± 0.2 rad) had similar stiffness but lower viscosity values than muscle tissue (SWS = 2.9 ± 0.5 m/s, φ = 1.4 ± 0.2 rad), whereas neuroblastoma (SWS = 2.4 ± 0.3 m/s, φ = 0.7 ± 0.1 rad, all p < .05) was the softest and least viscous tissue. Conclusion: Microscopic multifrequency MR elastography-generated maps of zebrafish show many details of viscoelasticity and resolve tissue regions, of great interest in neuromechanical and oncological research and for which our study provides first reference values

    Radioactive 26Al and massive stars in the Galaxy

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    Gamma-rays from radioactive 26Al (half life ~7.2 10^5 yr) provide a 'snapshot' view of ongoing nucleosynthesis in the Galaxy. The Galaxy is relatively transparent to such gamma-rays, and emission has been found concentrated along the plane of the Galaxy. This led to the conclusion1 that massive stars throughout the Galaxy dominate the production of 26Al. On the other hand, meteoritic data show locally-produced 26Al, perhaps from spallation reactions in the protosolar disk. Furthermore, prominent gamma-ray emission from the Cygnus region suggests that a substantial fraction of Galactic 26Al could originate in localized star-forming regions. Here we report high spectral resolution measurements of 26Al emission at 1808.65 keV, which demonstrate that the 26Al source regions corotate with the Galaxy, supporting its Galaxy-wide origin. We determine a present-day equilibrium mass of 2.8 (+/-0.8) M_sol of 26Al. We use this to estimate that the frequency of core collapse (i.e. type Ib/c and type II) supernovae to be 1.9(+/- 1.1) events per century.Comment: accepted for publication in Nature, 24 pages including Online Supplements, 11 figures, 1 tabl
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