Publications by authors named "Niemann R"

Nonlinear-optical microscopy and spectroscopy provide detailed spatial and spectroscopic contrast, specifically sensitive to structural symmetry and order. Ferroics, in particular, have been widely studied using second harmonic generation imaging, which provides detailed information on domain structures but typically lacks spectroscopic detail. In contrast, infrared-visible sum-frequency generation (SFG) spectroscopy reveals details of the atomic structure and bonding via vibrational resonances, but conventionally lacks spatial information.

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Phonon polaritons enable waveguiding and localization of infrared light with extreme confinement and low losses. The spatial propagation and spectral resonances of such polaritons are usually probed with complementary techniques such as near-field optical microscopy and far-field reflection spectroscopy. Here, infrared-visible sum-frequency spectro-microscopy is introduced as a tool for spectroscopic imaging of phonon polaritons.

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Nonlinear (vibrational) microscopy has emerged as a successful tool for the investigation of molecular systems as it combines label-free chemical characterization with spatial resolution on the sub-micron scale. In addition to the molecular recognition, the physics of the nonlinear interactions allows in principle to obtain structural information on the molecular level such as molecular orientations. Due to technical limitations such as the relatively complex imaging geometry with the required oblique sample irradiation and insufficient sensitivity of the instrument this detailed molecular information is typically not accessible using widefield imaging.

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In this paper, we analyze the effect of investor level taxes, firm-specific ownership structure and firm-specific dividend payout policy on a firm's capital structure choice. Our analysis is based on data for 10,003 firms from 11 Central and Eastern European (CEE) countries over the period 2002-2012. Our results show a significant positive impact from the net tax benefit of debt on the debt ratio of a firm.

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Heusler alloys exhibiting magnetic and martensitic transitions enable applications like magnetocaloric refrigeration and actuation based on the magnetic shape memory effect. Their outstanding functional properties depend on low hysteresis losses and low actuation fields. These are only achieved if the atomic positions deviate from a tetragonal lattice by periodic displacements.

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Tuning functional properties of thin caloric films by mechanical stress is currently of high interest. In particular, a controllable magnetisation or transition temperature is desired for improved usability in magnetocaloric devices. Here, we present results of epitaxial magnetocaloric Ni-Mn-Ga-Co thin films on ferroelectric Pb(MgNb)TiO (PMN-PT) substrates.

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Background: Reported results for thyroid nodule fine-needle aspiration (FNA) cytology mainly originate from tertiary centers. However, thyroid nodule FNA cytology is mainly performed in primary care settings for which the distribution of FNA Bethesda categories and their respective malignancy rates are largely unknown. Therefore, this study investigated FNA cytology malignancy rates of a large primary care setting to determine to what extent current evidence-based strategies for the malignancy risk stratification of thyroid nodules are applied and applicable in such primary care settings.

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Background: Major differences with respect to the diagnostic performance of a "ruling in" approach in the presurgical diagnosis of indeterminate thyroid fine-needle aspirations (FNAs) have been reported. Therefore, the aim of this prospective multicenter study was to investigate the specific diagnostic impact of mutation testing using a seven-gene panel in a routine primary referral setting analyzing FNAs from endocrinology and nuclear medicine practices in Germany.

Methods: RNA and DNA was extracted from 564 routine air-dried FNA smears obtained from 64 physicians and cytologically graded by one experienced cytopathologist.

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Consecutive admissions to the psychosomatic departments of 5 hospital units in southwest Germany registered between October 2012 and October 2013 were asked to participate in a study investigating the treatment selection process for psychosomatic rehabilitation. 527 patients were included in the study, 269 outpatients and 258 inpatients at the end of their inpatient treatment. 52 patients (10.

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FAM40B (STRIP2) is a member of the striatin-interacting phosphatase and kinase (STRIPAK) complex that is involved in the regulation of various processes such as cell proliferation and differentiation. Its role for differentiation processes in embryonic stem cells (ESCs) is till now completely unknown. Short hairpin RNA (shRNA)-mediated silencing of Fam40b expression in ESCs and differentiating embryoid bodies (EBs) led to perturbed differentiation to embryonic germ layers and their derivatives including a complete abrogation of cardiomyogenesis.

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Objective: We recently isolated and characterized endothelial-like CD31(+) cells derived from mouse embryonic stem (mES) cells and identified their transcriptome. The main objective of this study was to determine the functional relevance of the transcripts of unknown function (TUF) for vasculature development.

Methods And Results: We selected 2 TUFs of more than 27 to study their role for blood vessel development in zebrafish.

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Thiocyanate ranks after perchlorate as a potent inhibitor of iodide uptake by the thyroid but may be more concentrated in some food items such as milk products as to supersede perchlorate as the goitrogen of concern. A column-switching anion-exchange chromatographic method with UV spectral detection was developed to measure and confirm iodide and thiocyanate in powders of dry milk and infant formula. An aqueous solution was subjected to centrifugal ultrafiltration, the ultrafiltrate was cleaned up on a carbon solid-phase extraction column, and an aliquot was transferred to a precolumn for enrichment and subsequent injection onto an analytical column.

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A rapid, sensitive, and specific method was developed for the determination of perchlorate anion in foods. The foods included high moisture fruits and vegetables, low moisture foods (e.g.

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A molecular cytogenetic study was performed on 48 infertile patients who were identified as carriers of balanced translocations (40 cases), inversions (6 cases) or insertions (2 cases) by means of banding cytogenetics. Cases with a Robertsonian translocation or pericentric inversion 2 or 9 were not included. In summary, 100 break-events occurred in these patients, and 90 different chromosomal regions were involved.

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Systemic uptake of perchlorate anion, a rocket fuel component and potential thyroid function disruptor, by leafy vegetables and other crops grown in contaminated waters is a public health concern. A column-switching anion-exchange chromatographic method with suppressed conductivity detection, described in this paper, achieved a 3-6 microg/kg method limit of quantitation in analysis of the wet weight edible portion of cantaloupe, carrots, lettuce, and spinach samples with field-incurred perchlorate. A test portion was blended with dilute nitric acid, and the extract was filtered under vacuum.

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We report a simplified analytical procedure for determination of ephedrine alkaloids and synephrine in dietary supplements. Cleanup by simple filtration, when combined with tandem mass spectrometry (MS/MS) detection, provided results comparable to our published method with solid phase extraction (SPE) cleanup and single-stage MS detection with in-source fragmentation. We also compared three mass spectrometric experimental configurations: electrospray (ESI) and atmospheric pressure chemical ionization (APCI) with MS/MS and APCI-MS with fragmentation provided by increasing cone voltage.

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A rapid, sensitive, and specific method was developed for determining perchlorate anion in lettuce, cantaloupe, bottled water, and milk. A test portion of chopped crop homogenate was extracted with diluted nitric acid and filtered. Milk proteins were precipitated with acetonitrile, and the supernatant, after centrifugation, was cleaned up on a graphitized carbon solid-phase extraction column.

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An HPLC method with on-line cleanup coupled to the separation column is described for determination of (-)-norephedrine, (+)-norpseudoephedrine, (-)-ephedrine, (+)-pseudoephedrine, (-)-N-methylephedrine, (+)-N-methylpseudoephedrine, and (+/-)-synephrine in finished dietary supplement products. Test portions were extracted in acidified aqueous acetone. A filtered aliquot was cleaned up on a strong cation exchange (SCX) precolumn that later was automatically coupled to the SCX analytical column.

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Tacalcitol is a vitamin D analogue which ahs been developed for the therapy of psoriasis vulgaris. The treatment with a twice daily application of 2 micrograms/g ointment is efficacious and safe in Japanese patients. The objective of this randomized, placebo-controlled, intraindividual right-left comparison was to investigate the efficacy and safety of 8 weeks' therapy with a once daily application of a 4 micrograms/g tacalcitol ointment in Caucasian psoriatics.

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Essentiale and Lipostabil contain "essential" phospholipids from the soybean, mainly 1,2-dilinoleoyl-phosphatidylcholine (CAS 998-06-1, DLPC) which is considered as the main active ingredient. A single oral dose of d15-DLPC loaded with deuterium 9 times in the choline and 6 times in the linoleic acid of the 1-position was given to volunteers. Sera from 11 blood samples taken within 48 h after application were examined by means of mass spectrometry with regard to d9-choline and d6-linoleic acid in the 1- and 2-position of serum phosphatidylcholines (PC) as well as in the serum triglycerides.

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The acute toxicity of lindane, pentachlorophenol and a fluortenside was examined using a recently developed ecotoxicity test with the terrestrial nematode species Panagrellus redivivus. The exposure was performed in aqueous solution over an investigation period of 96 h. For lindane a time dependent decrease of the survival rate (LC50 after 96 h: 0.

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A strong cation exchange (SCX) liquid chromatographic (LC) method is described for determination of formetanate hydrochloride residue in pome, citrus, and stone fruits. A test portion of fruit, homogenized with the peel left on, was blended with acidified acetonitrile and filtered. A portion of extract was finely filtered, and a 500 microL aliquot (ca 0.

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An in vitro dye leakage study was performed to determine the incidence of patent furcal accessory canals following exposure of the pulp chamber to 5.25% sodium hypochlorite. One hundred extracted molars were labeled, endodontically opened, and irrigated for 1 h at 5-min intervals.

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