julilili42/papers huggingface dataset:
Molecular semiconductor blends: Microstructure, charge carrier transport, and application in photovoltaic cells
2009-11-18

Abstract Ambipolar organic semiconductor blends, i.e. mixtures of electron and hole conducting materials, attain growing interest due to their utilization in quasi‐complementary organic field‐effect transistors and organic photovoltaic cells. Many investigations in the latter field have reported an increase of the solar cell efficiency by optimizing the balance between charge carrier transport in phase‐separated structures and exciton dissociation at the interface between these phases. Here we show the implications of blending molecular materials for structural, optical, and electrical properties in two model systems for organic photovoltaic cells. We have investigated blends and neat films of the hole transporting material Cu‐phthalocyanine (CuPc) together with fullerene C 60 and Cu‐hexadecafluorophthalocyanine (F 16 CuPc) as electron transporting materials, respectively. On the one hand, the difference in molecular structure of the spherical C 60 and the planar molecule CuPc leads to nanophase separation in a blend of both of them, causing charge carrier transport being limited by the successful formation of percolation paths. On the other hand, blends of the similar shaped CuPc and F 16 CuPc molecules entail mixed crystalline films, as can be clearly seen by X‐ray scattering measurements. We discuss differences of both systems with respect to their microstructure as well as their electrical transport properties in diodes and field‐effect transistors. Furthermore, we compare the photovoltaic properties of planar‐ and bulk‐heterojunction devices under white light illumination to relate the different morphologies of both material systems to their performance in solar cells. magnified image Sketches of different molecular arrangements in blended systems. The formation of phase‐separated (left) or molecularly mixed crystalline films (right) can occur, depending on the geometry of the involved molecules.
“Metastable” Lu(GaMe4)3 Reacts Like Masked [LuMe3]: Synthesis of an Unsolvated Lanthanide Dimethyl Complex
2009-11-18

Homoleptic tetramethylgallate Lu(GaMe4)3 reacts selectively with superbulky (TptBu,Me)H according to a methane elimination reaction, affording the quantitative formation of monomeric base-free low-coordinate (TptBu,Me)LuMe2. Weak interaction of the strongly basic lanthanide methyl groups with the comparatively weak Lewis acid trimethylgallium in Lu(GaMe4)3 is indicated by their separation into [LuMe3]n and GaMe3 even at −35 °C.
Lipid emulsions – Guidelines on Parenteral Nutrition, Chapter 6
2009-11-18

The infusion of lipid emulsions allows a high energy supply, facilitates the prevention of high glucose infusion rates and is indispensable for the supply with essential fatty acids. The administration of lipid emulsions is recommended within ≤7 days after starting PN (parenteral nutrition) to avoid deficiency of essential fatty acids. Low-fat PN with a high glucose intake increases the risk of hyperglycaemia. In parenterally fed patients with a tendency to hyperglycaemia, an increase in the lipid-glucose ratio should be considered. In critically ill patients the glucose infusion should not exceed 50% of energy intake. The use of lipid emulsions with a low phospholipid/triglyceride ratio is recommended and should be provided with the usual PN to prevent depletion of essential fatty acids, lower the risk of hyperglycaemia, and prevent hepatic steatosis. Biologically active vitamin E (α-tocopherol) should continuously be administered along with lipid emulsions to reduce lipid peroxidation. Parenteral lipids should provide about 25–40% of the parenteral non-protein energy supply. In certain situations (i.e. critically ill, respiratory insufficiency) a lipid intake of up to 50 or 60% of non-protein energy may be reasonable. The recommended daily dose for parenteral lipids in adults is 0.7–1.3 g triglycerides/kg body weight. Serum triglyceride concentrations should be monitored regularly with dosage reduction at levels &gt;400 mg/dl (&gt;4.6 mmol/l) and interruption of lipid infusion at levels &gt;1000 mg/dl (&gt;11.4 mmol/l). There is little evidence at this time that the choice of different available lipid emulsions affects clinical endpoints.
Intracellular calcium signalling in Alzheimer’s disease
2009-11-19

More than two decades ago, dysregulation of the intracellular Ca(2+) homeostasis was suggested to underlie the development of Alzheimer's disease (AD). This hypothesis was tested in numerous in vitro studies, which revealed multiple Ca(2+) signalling pathways able to contribute to AD pathology. It remained, however, unclear whether these pathways are also activated in vivo, in cells involved in signal processing in the living brain. Here we review recent data analysing intracellular Ca(2+) signalling in vivo in the context of previous in vitro findings. We particularly focus on the processes taking place in the immediate vicinity of amyloid plaques and on their possible role for AD-mediated brain dysfunction.
Thermochronological constraints on the long-term erosional history of the Karkonosze Mts., Central Europe
2009-11-19

A combination of zircon (U-Th)/He (ZHe), apatite fission track (AFT) and apatite (U-Th-[Sm])/He (AHe) thermochronology is used to constrain the long-term exhumation and erosional history of the Karkonosze Mts. in north-eastern Bohemian Massif by analyzing samples from the highly elevated summit planation surface. ZHe ages from the south-eastern part of the planation surface are 285 +/- 19, 295 +/- 20 and 308 +/- 21 Ma, indicating that the area remained at temperatures below similar to 190 degrees C since the Permian. In contrast, ZHe ages in the western part of the planation surface are mid-Cretaceous, proving that this part was residing at temperatures above similar to 190 degrees C prior to exhumation. The exhumation occurred in the Late Cretaceous, as evidenced by AFT and AHe ages, ranging from 82 +/- 5 to 90 +/- 8 Ma and from 77 +/- 5 to 91 +/- 6 Ma, respectively. Modelled cooling trajectories are characterized by a two-stage cooling history: fast cooling through the apatite partial annealing zone and helium partial retention zone to surface conditions between similar to 90 and similar to 75 Ma, and slow cooling or even thermal stagnation from similar to 75 Ma to present. Although our data do not allow us to resolve the age of the planation surface completely, we narrowed down the number of explanatory options and propose two alternative solutions for the formation of the planation surface: (i) the planation surface represents the remnant of a Permian peneplain, which was buried by Mesozoic sediments of the Central European Basin System and was re-exposed in the Late Cretaceous: or, (ii) the planation surface formed after similar to 75 Ma, after termination of a period of massive erosion documented by thermochronological data and by the sedimentary record in adjacent basins. Cenozoic relief production and uplift of the planation surface, evident from regional landforms and the sedimentary record, is not recorded by thermochronological data. This shows that erosion on the uplifted planation surface since similar to 75 Ma was less than similar to 1.2 km. (C) 2009 Elsevier B.V. All rights reserved.
The dynamical origin of the multi-planetary system HD 45364
2009-11-19

The recently discovered planetary system HD45364 which consists of a Jupiter\\nand Saturn mass planet is very likely in a 3:2 mean motion resonance. The\\nstandard scenario to form planetary commensurabilities is convergent migration\\nof two planets embedded in a protoplanetary disc. When the planets are\\ninitially separated by a period ratio larger than two, convergent migration\\nwill most likely lead to a very stable 2:1 resonance for moderate migration\\nrates. To avoid this fate, formation of the planets close enough to prevent\\nthis resonance may be proposed. However, such a simultaneous formation of the\\nplanets within a small annulus, seems to be very unlikely.\\n Rapid type III migration of the outer planet crossing the 2:1 resonance is\\none possible way around this problem. In this paper, we investigate this idea\\nin detail. We present an estimate for the required convergent migration rate\\nand confirm this with N-body and hydrodynamical simulations. If the dynamical\\nhistory of the planetary system had a phase of rapid inward migration that\\nforms a resonant configuration, we predict that the orbital parameters of the\\ntwo planets are always very similar and hence should show evidence of that.\\n We use the orbital parameters from our simulation to calculate a radial\\nvelocity curve and compare it to observations. Our model can explain the\\nobservational data as good as the previously reported fit. The eccentricities\\nof both planets are considerably smaller and the libration pattern is\\ndifferent. Within a few years, it will be possible to observe the planet-planet\\ninteraction directly and thus distinguish between these different dynamical\\nstates.\\n
Transmembrane Signaling in Chimeras of the Escherichia coli Aspartate and Serine Chemotaxis Receptors and Bacterial Class III Adenylyl Cyclases
2009-11-19

The Escherichia coli chemoreceptors for serine (Tsr) and aspartate (Tar) and several bacterial class III adenylyl cyclases (ACs) share a common molecular architecture; that is, a membrane anchor that is linked via a cytoplasmic HAMP domain to a C-terminal signal output unit. Functionality of both proteins requires homodimerization. The chemotaxis receptors are well characterized, whereas the typical hexahelical membrane anchor (6TM) of class III ACs, suggested to operate as a channel or transporter, has no known function beyond a membrane anchor. We joined the intramolecular networks of Tsr or Tar and two bacterial ACs, Rv3645 from Mycobacterium tuberculosis and CyaG from Arthrospira platensis, across their signal transmission sites, connecting the chemotaxis receptors via different HAMP domains to the catalytic AC domains. AC activity in the chimeras was inhibited by micromolar concentrations of l-serine or l-aspartate in vitro and in vivo. Single point mutations known to abolish ligand binding in Tar (R69E or T154I) or Tsr (R69E or T156K) abrogated AC regulation. Co-expression of mutant pairs, which functionally complement each other, restored regulation in vitro and in vivo. Taken together, these studies demonstrate chemotaxis receptor-mediated regulation of chimeric bacterial ACs and connect chemical sensing and AC regulation.
Dental microwear of cave bears: The missing temperate/boreal vegetarian “carnivore”
2009-11-19

Peigne et al. (1) infer from dental microwear analysis of cave bears from Goyet, Belgium, that these bears had an omnivorous diet, at least before entering dormancy. This deduction is based on a comparison with a set of modern carnivores with different diets. However, the taxa chosen as reference may have biased the conclusions. Indeed, the chosen herbivorous bears are specialized and do not consume the possible food likely available to cave bears. Panda bears are specialized bamboo eaters and spectacled bears consume essentially fruits and arboreal plant parts (2). In contrast, the vegetal part of the diet of temperate and boreal bears (brown bears and American black bears) is mostly composed of grass, nuts, berries, and underground plant parts (2). Because the microwear study did not include members of these two species in the comparison, it is still unclear how such plant diets would impact the dental microwear pattern. The low 15N content of western European cave bear collagen points to a strongly vegetarian diet in contrast with that of coveal brown bears that exhibit isotopic signatures similar to those of pure carnivores (3, 4). However, the exact composition of this plant food and the possible seasonal and geographical variations in the diet of cave bears are yet to be determined. The dental microwear approach has a great potential to help resolve the riddle of cave bear diet, but it needs to be properly calibrated with reference bear samples with vegetarian diets from temperate and boreal environments.
ChemInform Abstract: Structural Revisions of Natural Products by Total Synthesis
2009-11-19

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Neuronal Encoding of Human Kinematic Invariants during Action Observation
2009-11-20

Human movements, besides entailing the presence of a body shape, comply with characteristic kinematic laws of motion. Psychophysical studies show that low-level motion perception is biased toward stimuli complying with these laws. However, the neuronal structures that are sensitive to the kinematic laws of observed bodily movements are still largely unknown. We investigated this issue by dissociating, by means of computer-generated characters, form and motion information during the observation of human movements. In a functional imaging experiment, we compared the levels of blood oxygen level-dependent activity elicited by human actions complying with or violating the kinematic laws of human movements. Actions complying with normal kinematic laws of motion differentially activated the left dorsal premotor and dorsolateral prefrontal cortex as well as the medial frontal cortex. These findings suggest that the kinematic laws of human movements specifically modulate the responses of neuronal circuits also involved in action recognition and that are predominantly located in the left frontal lobe.
Electronic Structure and Interface Properties of a Model Molecule for Organic Solar Cells
2009-11-20

Abstract We study the electronic structure of 4,7‐bis(5‐methylthiophen‐2‐yl)benzo[c][1,2,5]thiadiazole (MTBT) and its interface properties with gold using X‐ray photoemission spectroscopy (XPS), valence‐band ultraviolet photoemission spectroscopy (UPS), X‐ray absorption spectroscopy (XAS), as well as resonant photoemission (ResPES). MTBT can be regarded as a model molecule for PCPDTBT, a promising candidate for efficient bulk heterojunction solar cells. Almost no contribution of sulfur and only a weak contribution of nitrogen to the HOMO level is found. At the interface with gold, a strong chemical interaction between the sulfur of the benzothiadiazole and gold occurs, which may have consequences for interface properties in devices.
Two Cycles of ABVD Followed by Involved Field Radiotherapy with 20 Gray (Gy) Is the New Standard of Care in the Treatment of Patients with Early-Stage Hodgkin Lymphoma: Final Analysis of the Randomized German Hodgkin Study Group (GHSG) HD10. Study Supported by the Deutsche Krebshilfe and in Part by the Competence Network Malignant Lymphoma.
2009-11-20

Abstract Abstract 716 Background: There has been an ongoing debate on the best treatment for patients with early favourable Hodgkin lymphoma (HL). Open questions include the choice between combined modality treatment or chemotherapy only, the number of chemotherapy cycles needed and the optimal radiation dose. The GHSG thus conducted a randomized study for patients with early-stage favourable Hodgkin lymphoma (HD10) in which these questions were addressed. Methods: HD10 was an international prospectively randomized multicenter trial comparing 2 and 4 cycles of ABVD as well as 20Gy or 30Gy involved field radiotherapy (IFRT) in a 2 × 2 statistical design. Between 5/1998 and 1/2003, a total of 1370 patients from 329 centers were randomized into four arms: 4 × ABVD + 30Gy; 4 × ABVD + 20Gy; 2 × ABVD + 30Gy; 2 × ABVD + 20Gy. All patients had their initial histology reviewed by a lymphoma expert panel. Documentation was complete in more than 99,1% of cases for this final analysis. Results: Patients were equally balanced for age, gender, stage, histology, performance status and risk factors between arms. There were significant differences in major toxicity (WHO grade III/IV) between 4 × ABVD and 2 × ABVD in the overall number of events (52% vs 33%) including leukopenia (24% vs 15%) and hair loss (28% vs 15%). In terms of radiation dose, there also was a difference in toxicity between 30Gy and 20Gy IFRT (all events: 8.7% vs 2.9%), dysphagia (3% vs 2%), mucositis (3.4% vs 0.7%). Complete remission was achieved in 97% of patients treated with 4 × ABVD, 97% with 2 × ABVD, 99% after 30Gy and 97% after 20Gy. With a median follow-up of 79–91 months, there was no significant difference between 4 × ABVD and 2 × ABVD in terms of overall survival at 5 years (OS: 4 × ABVD 97.1%; 2 × ABVD: 96.6%), freedom from treatment failure (FFTF: 93.0% vs 91.1%) and progression free survival (PFS: 93.5% vs 91.2%). For the radiotherapy question, there were also no significant differences between patients receiving 30Gy IFRT and those with 20Gy IFRT in terms of OS (97.6% vs 97.5%), FFTF (93.4% vs 92.9%) and PFS (93.7% vs 93.2%), respectively. Importantly, there was also no significant difference in terms of OS, FFTF and PFS when all four arms were compared. Conclusion: Two cycles of ABVD followed by 20Gy IFRT is the new GHSG standard of care for Hodgkin patients in early favourable stages. Disclosures: No relevant conflicts of interest to declare.
Coating of Tumor Cells by Platelets Confers Expression of Immunoregulatory Molecules Which Impair NK Cell Anti-Tumor Reactivity.
2009-11-20

Abstract Abstract 2993 Poster Board II-970 NK cells play an important role in cancer immunosurveillance and may prevent tumor progression and metastasis due to their ability to mediate direct cellular cytotoxicity and by releasing immunoregulatory cytokines which shape adaptive immune responses. Their reactivity is governed by various activating and inhibitory molecules expressed on target cells and reciprocal interactions with other hematopoietic cells like dendritic cells. Platelets contribute to tumor immune escape, metastasis, and angiogenesis (e.g. Jin et al Nature Med. 2006). In mice, thrombocytopenia inhibits metastasis, and this is reversed by NK cell depletion suggesting that platelets are an important additional player in NK cell-tumor interaction. However, the knowledge regarding the molecular mechanisms by which platelets influence NK cells is fragmentary at best. We found recently that platelet release soluble factors, most notably TGF-β, upon interaction with tumor cells which mediates NK cell silencing through downregulation of the activating immunoreceptor NKG2D (Kopp et al., Cancer Res 2009, in press). However, immunoregulatory molecules residing in the platelet membrane may also modulate NK cell anti-tumor responses. We report here that presence of platelets causes coating of tumor cells, and this markedly reduces NK cell lysis of tumor cells. This is mediated by conferment of “pseudoexpression” of platelet-expressed immunoregulatory molecules to tumor cells which are absent on the tumor cells alone. Among those immunregulatory molecules we identified various ligands for NK cell receptors like MHC class I, GITR ligand or CD62P. To establish the functional significance of tumor cell pseudoexpression of platelet molecules we employed functional analyses of tumor cells and NK cells with or without coating by autologous platelets. The impaired anti-tumor reactivity of NK cells against coated tumor cells was restored by blocking MHC class I on the coating platelets, while isotype control had no effect. Moreover, coating of tumor cells by platelets was validated by ex vivo analyses of primary leukemic cells from patients which also revealed substantial coating by platelets and confered expression of NK cell-modulating molecules. Our data indicate that platelets enable a molecular mimicry of tumor cells, which enables tumor cells to escape NK cell-mediated tumor immunosurveillance. Disclosures: No relevant conflicts of interest to declare.
The Role of the PI3K-AKT-mTOR Pathway in NK Cell Anti-Tumor Reactivity.
2009-11-20

Abstract Abstract 3690 Poster Board III-626 The phosphatidylinositol 3-kinase – protein kinase B – mammalian target of rapamycin (PI3K – AKT – mTOR) pathway was found to be abnormally activated in many malignancies. Thus, protein kinase (PK) inhibitors (PKI) targeting different signaling molecules of this pathway are presently under clinical evaluation e.g. in sarcoma, multiple myeloma, or renal cell cancer. However, PK are also responsible for most of the signal transduction in immune effector cells and control various effector mechanisms including proliferation, cellular cytotoxicity, and cytokine release. Among those immunoregulatory signaling pathways, the PI3K – AKT – mTOR pathway was found to play a central role in TLR-mediated release of cytokines in macrophages and DC as well as in the regulation of T cell functions. Little is known about the role of this pathway in NK cell-mediated anti-tumor reactivity. Here we analyzed the tumor cell-induced activation of PI3K, AKT, and mTOR in NK cells and the consequences of an inhibition of these molecules by therapeutic PKI for NK cell anti-tumor reactivity. We found that, in response to tumor target cells, PI3K, AKT, and mTOR are consecutively activated in NK cells as revealed by western blot analyses using phospho-specific antibodies. Presence of the specific PI3K-inhbitor BKM-120 concentration-dependently inhibited cytotoxicity and IFN-g production of NK cells, which is in line with available data defining PI3K as a central regulator of NK cell target recognition. The mTOR inhibitors Sirolimus, Temsirolimus, and Everolimus did not alter cytotoxicity but significantly impaired NK cell IFN-γ production. In contrast, Triciribine, a compound which inhibits the phosphorylation and thus activation of AKT, did not influence cytotoxicity and, tantalizingly, even enhanced NK cell IFN-γ production. Thus, after target cell recognition and the activation of proximal PK like PI3K, different and at least partially independent signaling events govern NK cell cytokine production and cellular cytotoxicity. While the activity of PI3K followed by the activation of mitogen-activated PK is known to be crucial for NK cell cytotoxicity, we here identified the AKT – mTOR pathway as a yet unknown central component in the regulation of NK cell IFN-γ production. Moreover, in light of the important role of NK cells in tumor immune surveillance our data indicate that the choise and dosing of the most suitable PKI for a given cancer patient requires careful consideration. In the future it will be critical to define potential differences in immunosuppressive and immunostimulatory side effects of different compounds among the rapidly growing assortment of multi-targeted PKI to enable therapeutic approaches combining targeting of crucial signaling pathways in tumor cells with immunotherapy. Disclosures: No relevant conflicts of interest to declare.