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Instrumental neutron activation analysis with both relative and k0 standardization was used in four experienced laboratories to determine element mass fractions in single-wall carbon nanotube certified reference material (CRM) SWCNT-1. Results obtained were evaluated using the National Institute of Standards and Technology (NIST) "Type B On Bias" approach and yielded consensus values in agreement with National Research Council Canada (NRCC) certified values for Fe, Co, Ni, and Mo and provided mass fraction values for 13 additional elements, namely, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Br, La, W, and Au. In addition, prompt γ neutron activation analysis was employed to determine mass fractions of H, B, Co, Ni, and Mo. Results of this work provide a basis for the establishment of reference values of element mass fractions in CRM SWCNT-1, thus expanding its usability for more accurate characterization and benchmarking of similar nanotechnology materials.

Gamma- and neutron doses in an experimental reactor were measured using alanine/electron spin resonance (ESR) spectrometry. The absorbed dose in alanine was decomposed into contributions caused by gamma and neutron radiation using neutron kerma factors. To overcome a low sensitivity of the alanine/ESR response to thermal neutrons, a novel method has been proposed for the assessment of a thermal neutron flux using the (14)N(n,p) (14)C reaction on nitrogen present in alanine and subsequent measurement of (14)C by liquid scintillation counting (LSC)., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Hyaluronan-based tissue substitutes are promising materials in cartilage reconstruction surgery. Herein, the chondrogenesis of human mesenchymal stem cells (MSC) in a hydrogel based on a tyramine derivative of hyaluronan crosslinked by hydrogen peroxidase (HA-TA) was evaluated. Human MSC seeded in the scaffold were incubated in standard chondrogenic medium and medium enriched with bone morphogenetic protein-6 (BMP6). Cell viability, the gene expression of selected markers (collagen type II, aggrecan, SOX9, collagen type X, and osteopontin), and the histological characteristics were examined during three weeks of in vitro cultivation. The tissue reaction of both unseeded and MSC seeded HA-TA scaffolds were tested in vivo after subcutaneous application in rats for 12 weeks. The data showed that cells resisted the process of crosslinking and remained viable for the whole time while exhibiting changes in cell organization. Human MSC cultivated in HA-TA hydrogel expressed genes of both chondrogenic and osteogenic differentiation and the addition of BMP6 revealed a tendency to potentiate both processes. Histological analysis of HA-TA in vivo implants did not reveal a chronic inflammatory reaction. In both cases, in vivo HA-TA implants were continuously degraded and MSC-seeded hydrogels tended to form clusters similar to in vitro samples. In conclusion, MSC chondrogenic differentiation may proceed in a HA-TA scaffold that is biocompatible. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3523-3530, 2014., (© 2013 Wiley Periodicals, Inc.)

The synthesis of graphene materials is typically carried out by oxidizing graphite to graphite oxide followed by a reduction process. Numerous methods exist for both the oxidation and reduction steps, which causes unpredictable contamination from metallic impurities into the final material. These impurities are known to have considerable impact on the properties of graphene materials. We synthesized several reduced graphene oxides from extremely pure graphite using several popular oxidation and reduction methods and tracked the concentrations of metallic impurities at each stage of synthesis. We show that different combinations of oxidation and reduction introduce varying types as well as amounts of metallic elements into the graphene materials, and their origin can be traced to impurities within the chemical reagents used during synthesis. These metallic impurities are able to alter the graphene materials' electrochemical properties significantly and have wide-reaching implications on the potential applications of graphene materials.

We investigated genetic variation and evolutionary history of closely related taxa of Picris subsect. Hieracioides with major focus on the widely distributed P. hieracioides and its closely related congeners, P. hispidissima, P. japonica, P. olympica, and P. nuristanica. Accessions from 140 sample sites of the investigated Picris taxa were analyzed on the infra- and the inter-specific level using nuclear (ITS1-5.8S-ITS2 region) and chloroplast (rpl32-trnL(UAG) region) DNA sequences. Genetic patterns of P. hieracioides, P. hispidissima, and P. olympica were shown to be incongruent and, in several cases, both plastid and nuclear alleles transcended borders of the taxa and genetic lineages. The widespread P. hieracioides was genetically highly variable and non-monophyletic across both markers, with allele groups having particular geographic distributions. Generally, all gene trees and networks displayed only a limited and statistically rather unsupported resolution among ingroup taxa causing their phylogenetic relationships to remain rather unresolved. More light on these intricate evolutionary relationships was cast by the Bayesian coalescent-based analysis, although some relationships were still left unresolved. A combination of suite of phylogenetic analyses revealed the ingroup taxa to represent a complex of genetically closely related and morphologically similar entities that have undergone a highly dynamic and recent evolution. This has been especially affected by the extensive and recurrent gene flow among and within the studied taxa and/or by the maintenance of ancestral variation. Paucity of phylogenetically informative signal further hampers the reconstruction of relationships on the infra- as well as on the inter-specific level. In the present study, we have demonstrated that a combination of various phylogenetic analyses of datasets with extremely complex and incongruent phylogenetic signal may shed more light on the interrelationships and evolutionary history of analysed species groups.

Cancer-associated fibroblasts (CAFs) play a role in the progression of malignant tumors. They are formed by conversion of fibroblasts to smooth muscle α-actin-positive (SMA-positive) myofibroblasts. Polyamines are known to change the arrangement of the actin cytoskeleton by binding to the anionic actin. We tested the effect of the synthetic polyamine BPA-C8 on the transition of human dermal fibroblasts to myofibroblasts induced either by TGF-β1 alone or by TGF-β1 together with adhesion/growth-regulatory galectin-1. Pre-existing CAFs, myofibroblasts from pancreatitis, and rat smooth muscle cells were also exposed to BPA-C8. BPA-C8 impaired myofibroblast formation from activated fibroblasts, but it had no effect on cells already expressing SMA. BPA-C8 also reduced the occurrence of an extracellular matrix around the activated fibroblasts. The reported data thus extend current insights into polyamine activity, adding interference with tumor progression to the tumor-promoting processes warranting study., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Studies in Microglossum viride (Pers.) Gillet revealed that the name was used incorrectly for two similar but different taxa. Analyses of morphological, ecological and molecular (sequences of ITS and LSU region of rRNA gene) characters of type and voucher specimens of M. viride and related taxa resulted in delimitation and description of a new species, Microglossum griseoviride V. Kučera, Lizoň & M. Tomšovský. Lectotypes of Geoglossum viride Pers., and epitype of Geoglossum viride are designated. Species Microglossum minus Velen. and Microglossum lutescens Boud. are confirmed to be conspecific to M. viride.

Background: There are only 4 unequivocal cases of metastasizing middle ear carcinoid previously reported., Objective: To present a case of metastasizing middle ear carcinoid, to review previously reported cases, and to discuss the clinical nature of this tumor, which is similar to "orthotopic" carcinoids bearing definite metastatic potential., Study Design: Case report. PATIENT, INTERVENTION, RESULTS: We present a 72-year-old woman who developed ipsilateral parotid gland and cervical lymph node metastases 8 and 11 months after surgical removal of a primary middle ear lesion. She subsequently required 2 revision procedures and radiotherapy for local recurrences. Her case was complicated by nonsurgically induced permanent facial nerve paralysis, the cause of which remains obscure. At the end of the 8-year follow-up, the patient was alive with locally, recurrent tumor eroding the cranial base and invading the posterior intracranial fossa but with no signs of metastases., Main Outcome Measures: Light microscopy and immunohistochemical analysis., Conclusion: Considering the reported high rate of recurrence and their consequent metastases, a middle ear carcinoid should be classified as a neuroendocrine low-grade carcinoma.

Experiments have shown that a Pd monolayer deposited electrochemically on a Au-supported self-assembled monolayer (SAM) of 4-mercaptopyridine (Mpy) exhibits a strongly reduced Pd local density of states (LDOS) at the Fermi energy (E(f)). Understanding the origin of this modified electronic structure is crucial for the use of the sandwich design as a platform for future nanoelectronics. Here we suggest that hydrogen adsorption might be the origin of the modified electronic properties. We performed periodic density functional theory calculation to explore the influence of hydrogen adsorption on the geometric and electronic structure of a Pd/Mpy/Au(111) complex. Dissociative adsorption of H(2) on a Pd monolayer on top of a Mpy SAM is a strongly exothermic process leading to atomic hydrogen atoms preferentially located at the hollow sites. Due to the formation of a strong Pd-H bond the Pd-SAM interaction realized via one-fold N-Pd bonds is substantially weakened. Upon hydrogen adsorption, the Pd LDOS becomes significantly modified exhibiting a drastic reduction of the density of states at E(f). The calculated spectra are in a good agreement with the experiment for a hydrogen coverage corresponding to two monolayers which is still thermodynamically allowed.

Retinoic acid (RA) is able to induce the differentiation of embryonic stem cells into neuronal lineages. The mechanism of this effect is unknown but it has been evidenced to be dependent on the formation of floating spheroids called embryoid bodies. Results presented here show that the inhibition of phosphoinositide 3-kinase signaling pre-determines mouse embryonic stem cells to RA induced neurogenesis in monolayer culture with no need of embryoid bodies formation., (Copyright © 2011 Wiley Periodicals, Inc.)

The geometric and electronic structure of the metal-molecule interface in metal/molecule/metal junctions is of great interest since it affects the functionality of such units in possible nanoelectronic devices. We have investigated the interaction between water and a palladium monolayer of a Au(111)/4-mercaptopyridine/Pd junction by means of DFT calculations. A relatively strong bond between water and the palladium monolayer of the Au/Mpy/Pd complex is observed via a one-fold bond between the oxygen atom of the water molecule and a Pd atom. An isolated H(2)O molecule adsorbs preferentially in a flat-lying geometry on top of a palladium atom that is at the same time also bound to the nitrogen atom of a Mpy molecule of the underlying self-assembled monolayer. The electronic structure of these Pd atoms is considerably modified which is reflected in a reduced local density of states at the Fermi energy. At higher coverages, water can be arranged in a hexagonal ice-like bilayer structure in analogy to water on bulk metal surfaces, but with a much stronger binding which is dominated by O-Pd bonds.

The diurnal course of the xylem water flow in a solitary Salix fragilis L. tree in a wet grassland was measured using the tissue heat-balance method. There was considerable variation due to meteorological factors. Maximum flow rate was 0.4 kg h -1 m -2 of crown projection area, or 5.9 kg h -1 kg -1 leaf dry weight. The daily total was 2.4 kg m -2 day -1 or 36 kg kg -1 day -1 . Water flow decreased immediately at the tree base and at the branches after start of rain, and in a branch, after cutting it off: the time constant of the system was 600-700 s in both cases. The part of the crown oriented to the sun transpired up to ten times as much as the shaded part. Over 70% of the total cross-sectional area of the conductive xylem vessels of the trunk was used by the transpiration flow. The water content of the trunk tracked the diurnal changes of the xylem water flow rate with a short time-lag. During the day, 1% of the trunk volume was temporarily exploited as water reserve, an amount equalling 3% of daily water loss. The stereometric configuration of the crown significantly influenced its water loss. During the summer period, about 33 mature (polycormic) trees per ha may drain 100% of water consumed by the present-day sedge-grass marsh.

Leaf gas exchange, transpiration, water potential and xylem water flow measurements were used in order to investigate the daily water balance of intact, naturally growing, adult Larix and Picea trees without major injury. The total daily water use of the tree was very similar when measured as xylem water flow at breast height or at the trunk top below the shade branches, or as canopy transpiration by a porometer or gas exchange chamber at different crown positions. The average canopy transpiration is about 12% lower than the transpiration of a single twig in the sun crown of Larix and Picea. Despite the similarity in daily total water flows there are larger differences in the actual daily course. Transpiration started 2 to 3 h earlier than the xylem water flow and decreased at noon before the maximum xylem water flow was reached, and stopped in the evening 2 to 3 h earlier than the water flow though the stem. The daily course of the xylem water flow was very similar at the trunk base and top below the lowest branches with shade needles. The difference in water efflux from the crown via transpiration and the water influx from the trunk is caused by the use of stored water. The specific capacitance of the crown wood was estimated to be 4.7 x 10 -8 and 6.3 x 10 -8 kg kg -1 Pa -1 and the total amount of available water storage was 17.8 and 8.7 kg, which is 24% and 14% of the total daily transpiration in Larix and Picea respectively. Very little water was used from the main tree trunk. With increasing transpiration and use of stored water from wood in the crown, the water potential in the foliage decreases. Plant water status recovers with the decrease of transpiration and the refilling of the water storage sites. The liquid flow conductance in the trunk was 0.45 x 10 -9 and 0.36 x 10 -9 mol m -2 s -1 Pa -1 in Larix and Picea respectively. The role of stomata and their control by environmental and internal plant factors is discussed.