julilili42/papers huggingface dataset:
Stem Cells and Cartilage Repair
2010-12-03

Articular cartilage together with the synovial fluid acts as a mechanical shock absorber, provides lubrication for gliding joint surfaces, and serves as an elastic connection between the articulating joint surfaces. It contains relatively few cells, the chondrocytes, but no blood or lymph vessels or nerves. Cartilaginous tissue has a very limited capacity for self-regeneration; therefore, techniques for cell-based cartilage repair were developed in the mid-nineties of the last century. For such therapies mature chondrocytes are harvested from healthy cartilage of the affected joint and implanted into the defect after in vitro expansion. This therapy works well if chondrocytes from donor tissue are available. In this chapter we discuss recent progress in cell-based tissue engineering utilizing chondrogenic progenitor cells (so-called mesenchymal stem/stromal cells (MSCs)) as surrogate cell source. The MSC characteristics, their potential but also their limitations in MSC-based cartilage repair will be discussed. In addition, the reader will be introduced to some of the current tasks in developing MSC-based therapies for the health market.
Regeneration of the Lower Urinary Tract: Clinical Applications and Future Outlook
2010-12-03

Due to the absence of transplantable organ resources and the reconstructive urological demand, researchers have been called to action in order advance tissue engineering and stem cell research. As the archetype of pluripotent cells, human embryonic stem cells (hESCs) and inducible stem cells (iPS) are still far from any clinical application, whereas new and interestingly adult sources of stem cells are coming into focus. Such urological reconstructive approaches such as adult myoblasts for an autologous therapy option of stress urinary incontinence and the recently advances in pluripotent adult human germline stem cells (haGSCs) have a potentially suitable application in male reconstructive medicine. Further and comparable progress must be made in the female approach. Despite its histological complexity, there has been a huge progression in the development of renal tissue formation. Even the feasibility of engineering the entire pendular penile corporal bodies in a rabbit model could be shown. The further development of suitable surgical harvesting and implantation techniques allow sufficient and functional graft survival. Urological TE should be positioned as “a young field” that promises to influence urological treatment in the “near future”.
Integrating Neurobiological Markers of Depression
2010-12-06

Our method of integrating neuroimaging data associated with multiple, symptom-related neural processes can provide a highly accurate algorithm for classification. The integrated biomarker model shows that data associated with both emotional and reward processing are essential for a highly accurate classification of depression. In the future, large-scale studies will need to be conducted to determine the practical applicability of our algorithm as a biomarker-based diagnostic aid.
The gametic central cell of Arabidopsis determines the lifespan of adjacent accessory cells
2010-12-06

Plant germ cells develop in specialized haploid structures, termed gametophytes. The female gametophyte patterns of flowering plants are diverse, with often unknown adaptive value. Here we present the Arabidopsis fiona mutant, which forms a female gametophyte that is structurally and functionally reminiscent of a phylogenetic distant female gametophyte. The respective changes include a modified reproductive behavior of one of the female germ cells (central cell) and an extended lifespan of three adjacent accessory cells (antipodals). FIONA encodes the cysteinyl t-RNA synthetase SYCO ARATH (SYCO), which is expressed and required in the central cell but not in the antipodals, suggesting that antipodal lifespan is controlled by the adjacent gamete. SYCO localizes to the mitochondria, and ultrastructural analysis of mutant central cells revealed that the protein is necessary for mitochondrial cristae integrity. Furthermore, a dominant ATP/ADP translocator caused mitochondrial cristae degeneration and extended antipodal lifespan when expressed in the central cell of wild-type plants. Notably, this construct did not affect antipodal lifespan when expressed in antipodals. Our results thus identify an unexpected noncell autonomous role for mitochondria in the regulation of cellular lifespan and provide a basis for the coordinated development of gametic and nongametic cells.
Fine‐tuned coupling between human parahippocampal ripples and sleep spindles
2010-12-07

Abstract Sleep‐associated memory consolidation is thought to rely on coordinated information transfer between the hippocampus and neocortex brought about during slow wave sleep (SWS) by distinct local field potential oscillations. Specifically, findings in animals have led to the concept that ripples originating from hippocampus combine with spindles to provide a fine‐tuned temporal frame for a persistent transfer of memory‐related information to the neocortex. The present study focused on characterizing the temporal relationship between parahippocampal ripple activity (80–140 Hz) and spindles recorded from frontal, parietal and parahippocampal cortices in 12 epilepsy patients implanted with parahippocampal foramen ovale electrodes. Overall, parietal and parahippocampal spindles showed closer relationships to parahippocampal ripple activity than frontal spindles, with the latter following parietal and parahippocampal spindles at a variable delay of up to 0.5 s. On a timescale of seconds, ripple activity showed a continuous increase before the peak of parietal and parahippocampal spindles, and decreased thereafter. At a fine timescale of milliseconds, parahippocampal ripple activity was tightly phase‐locked to the troughs of these spindles. The demonstration of spindle phase‐locked ripple activity in humans is consistent with the idea of a temporally fine‐tuned hippocampus‐to‐neocortex transfer of information taking place during SWS.
The performance of zirconium dioxide crowns: a clinical follow-up.
2010-12-07

Thirty-two patients who had been treated with 71 computer-aided design/computer-assisted manufacture-fabricated Cercon crowns were followed to assess clinical performance by time-to-event analysis. Clinical examinations consisted of a complete dental and oral hygiene examination and a quality assessment by modified California Dental Association criteria. Four patients (6 crowns) were lost to follow-up; another 11 crowns had to be excluded from evaluation for comparability reasons. Six of 54 evaluated crowns experienced complications (P(C) = 11.1%) throughout a mean observation time of 21 months. Survival was estimated at 0.98 over 24 months. The good overall clinical performance was affected predominantly by technical complications of the veneering ceramic (P(TC) = 9.3%).
Coordination of apical and basal embryo development revealed by tissue-specific GNOM functions
2010-12-07

Flowering-plant embryogenesis generates the basic body organization, including the apical and basal stem cell niches, i.e. shoot and root meristems, the major tissue layers and the cotyledon(s). gnom mutant embryos fail to initiate the root meristem at the early-globular stage and the cotyledon primordia at the late globular/transition stage. Tissue-specific GNOM expression in the gnom mutant embryo revealed that both apical and basal embryo organization depend on GNOM provascular expression and a functioning apical-basal auxin flux: GNOM provascular expression in gnom mutant background resulted in non-cell-autonomous reconstitution of apical and basal tissues which could be linked to changes in auxin responses in those tissues, stressing the importance of apical-basal auxin flow for overall embryo organization. Although reconstitution of apical-basal auxin flux in gnom results in the formation of single cotyledons (monocots), only additional GNOM epidermal expression is able to induce wild-type apical patterning. We conclude that provascular expression of GNOM is vital for both apical and basal tissue organization, and that epidermal GNOM expression is required for radial-to-bilateral symmetry transition of the embryo. We propose GNOM-dependent auxin sinks as a means to generate auxin gradients across tissues.
Temporal and Spatial Aspects of Snow Distribution in the Nam Co Basin on the Tibetan Plateau from MODIS Data
2010-12-07

Large areas of the Tibetan plateau are only covered by a sparse network of ground snow sampling stations, while the snow cover is highly heterogeneously distributed due to wind, topography etc. Nevertheless, the snow accumulation and spatial patterns play an important role in the hydrological cycle. It releases moisture during the dry spring period before the onset of the monsoon season. Widely used MODIS snow cover products have been available globally since 2002. The understanding of the temporal and spatial distribution of snow cover in a given region calls for a comprehensive data representation method. In this paper a method to visualize both spatial and temporal aspects of snow cover distribution from MODIS 8-day composite data is presented. It is based on RGB display of the snow cover data which is grouped according to season. The RGB syntheses of snow cover distribution (RSD) were generated for the Nam Co Basin in the central part of the Tibetan Plateau during the years of 2002–2009. An alternating pattern of monsoon and autumn snow cover was identified in the western part of the basin which corresponds to the biennial character of the variations of the Indian monsoon. Monsoon snow cover was found in RSD images for the years 2002, 2004 and 2008 whereas in years 2003 and 2009 the autumn snow cover is dominant. The eastern part of the basin does not follow this general pattern since it is affected by the so called “lake effect”, which is a snow fall induced by the passing of dry and cold westerlies over the lake surface during the winter months. The years 2002, 2006 and 2007 were identified as years with a particularly strong lake effect from the RSD images. Areas with permanent snow cover and areas that were snow free were both found to be relatively stable. Comparison of the lake effect at Nam Co with nearby Siling Co, where the lake effect is smaller or absent, suggests that the presence of an effective barrier on the opposite side of the lake is a prerequisite for the occurrence of the strong lake effect.
Onset of Industrial Pollution Recorded in Mumbai Mudflat Sediments, Using Integrated Magnetic, Chemical, 210Pb Dating, and Microscopic Methods
2010-12-07

The onset and rise of urban and industrial pollution in the Mumbai region was reconstructed from an anthropogenically contaminated mudflat sediment profile from the adjacent Thane creek using magnetic parameters, polycyclic aromatic hydrocarbon (PAH) data, metal contents, and the (210)Pb dating technique. The 1.8 m vertical section at Airoli (Navi Mumbai) reveals an increase of magnetic susceptibility (χ) from background values of (20-50) to (75-100) × 10(-8) [m(3) kg(-1)] in the anthropogenically affected zone above ∼93 cm. A sharp rise of χ from (75-100) to (130-215) × 10(-8) [m(3) kg(-1)] subdivides the anthropogenically affected zone at a depth of ∼63 cm. Characterization with rock magnetic parameters (SIRM, Soft IRM, and S-ratio) reveals a significant contribution of ferri(o)magnetic phases in the upper zone. Based on the magnetic classification sampling intervals for cost-intensive PAH and metal analyses were determined. Steadily increasing contents of PAH and metals of anthropogenic origin are observed above the boundary depth at ∼93 cm. A sediment accumulation rate of 1.2 ± 0.3 cm/yr provided by (210)Pb dating dates the ∼63 cm boundary to 1951. Increasing industrial activity, including the establishment of a coal-fired power plant in 1956, and refineries between 1955 and 1960, correlates well with the substantial increase of χ, PAH, and metal contents. Scanning electron microscopy (SEM) investigation on magnetic extracts from the contaminated zone reveals the presence of magnetic spherules derived from industrial high-temperature processes.
Anomeric effect in N-azidomethylpyrrolidine: gas-phase electron diffraction and theoretical study
2010-12-07

Gas-phase electron-diffraction data and high-level quantum chemical calculations have been used to study the conformational behaviour of N-azidomethylpyrrolidine. The two most stable conformers with a relative abundance of about 80% at 298 K possess gauche orientation of the azidomethyl group around the C-N(pyr) bond (C-N(azido)gauche with respect to the endocyclic N(pyr)-C bond). This orientation is a strong manifestation of an anomeric effect. The influence of the anomeric effect is also reflected in shortening of the C-N(pyr) bond and lengthening of the C-N(azido) bond as compared to such bonds in other compounds.
Silylation Efficiency of Chorosilanes, Alkoxysilanes, and Monosilazanes on Periodic Mesoporous Silica
2010-12-08

Because of their large surface area and distinct pore architecture, periodic mesoporous silica (PMS) are predisposed to study the reactivity of surface silanol groups. Surface silylation involving the formation of thermodynamically stable O−SiR3 moieties is a powerful and probably the most prominent postsynthesis functionalization method of oxidic support materials. This study will assess the reactivity/silylation behavior of similarly sized dimethyloctylsilazane (Me2NSiMe2(C8H17)), dimethyloctylchlorosilane (ClSiMe2(C8H17)), and octyltriethoxysilane ((EtO)3Si(C8H17)), toward periodic mesoporous silica MCM-41 (BET surface as = 1060 m2/g, pore volume Vp = 1.14 cm3/g, pore diameter dp = 4.0 nm, silanol population = 3.47 mmol/g) and SBA-1 (as = 1260 m2/g, Vp = 0.73 cm3/g, Dme = 4.5 nm, silanol population = 4.45 mmol/g). A medium-long aliphatic tail (C8) was chosen to ensure a reliable elemental (carbon) analysis and to study any size-selective behavior of cagelike SBA-1. For channel-like MCM-41, the obtained hybrid materials reveal a superior silylation efficiency (SE) of the monosilazane reagent compared to the chloro- and ethoxysilanes (SE = 81% versus 67% versus 22%, use of excess of silylating reagent), the latter two reagents requiring either elevated temperature (125 °C) or stoichiometric amounts of a base (NEt3). For cagelike SBA-1, site-specific reactivity of the monosilazane reagent at the outer surface and pore openings was observed, finally resulting in pore blockage. Even under harsher reaction conditions, the chloro- and ethoxysilanes gave a more random surface silylation, however with lower SE values (SE = 76% versus 62% versus 32%; use of excess of silylating reagent). All materials were characterized by FTIR spectroscopy, nitrogen physisorption, elemental analysis, and transmission electron microscopy.
Coulomb gauge ghost Dyson–Schwinger equation
2010-12-08

A numerical study of the ghost Dyson-Schwinger equation in Coulomb gauge is\\nperformed and solutions for the ghost propagator found. As input, lattice\\nresults for the spatial gluon propagator are used. It is shown that in order to\\nsolve completely, the equation must be supplemented by a nonperturbative\\nboundary condition (the value of the inverse ghost propagator dressing function\\nat zero momentum) which determines if the solution is critical (zero value for\\nthe boundary condition) or subcritical (finite value). The various solutions\\nexhibit a characteristic behavior where all curves follow the same (critical)\\nsolution when going from high to low momenta until `forced' to freeze out in\\nthe infrared to the value of the boundary condition. The renormalization is\\nshown to be largely independent of the boundary condition. The boundary\\ncondition and the pattern of the solutions can be interpreted in terms of the\\nGribov gauge-fixing ambiguity. The connection to the temporal gluon propagator\\nand the infrared slavery picture of confinement is explored.\\n
Analyzing X-ray pulsar profiles: geometry and beam pattern of A 0535+26
2010-12-08

\\n Aims. We applied a decomposition method to the energy dependent pulse profiles of the accreting binary pulsar A 0535+26, in order to identify the contribution of the two magnetic poles of the neutron star and to obtain constraints on the geometry of the system and on the beam pattern. \\n Methods. We analyzed pulse profiles obtained from RXTE observations in the X-ray regime. Basic assumptions of the method are that the asymmetry observed in the pulse profiles is caused by non-antipodal magnetic poles and that the emission regions have axisymmetric beam patterns. \\n Results. Constraints on the geometry of the pulsar and a possible solution of the beam pattern are given. We interpreted the reconstructed beam pattern in terms of a geometrical model of a hollow column plus a halo of scattered radiation on the neutron star surface, which includes relativistic light deflection. \\n
The biosynthetic genes for prenylated phenazines are located at two different chromosomal loci of Streptomyces cinnamonensis DSM 1042
2010-12-08

Summary Streptomyces cinnamonensis DSM 1042 produces two types of isoprenoid secondary metabolites: the prenylated naphthalene derivative furanonaphthoquinone I (FNQ I), and isoprenylated phenazines which are termed endophenazines. Previously, a 55 kb gene cluster was identified which contained genes for both FNQ I and endophenazine biosynthesis. However, several genes required for the biosynthesis of these metabolites were not present in this cluster. We now re‐screened the cosmid library for genes of the mevalonate pathway and identified a separate genomic locus which contains the previously missing genes. This locus (15 kb) comprised orthologues of four phenazine biosynthesis genes known from Pseudomonas strains. Furthermore, the locus contained a putative operon of six genes of the mevalonate pathway, as well as the gene epzP which showed sequence similarity to a recently discovered class of prenyltransferases. Inactivation and complementation experiments proved the involvement of epzP in the prenylation reaction in endophenazine biosynthesis. This newly identified genomic locus is more than 40 kb distant from the previously identified cluster. The protein EpzP was expressed in Escherichia coli in form of a his‐tag fusion protein and purified. The enzyme catalysed the prenylation of 5,10‐dihydrophenazine‐1‐carboxylic acid (dihydro‐PCA) using dimethylallyl diphosphate (DMAPP) as isoprenoid substrate. K m values were determined as 108 μM for dihydro‐PCA and 25 μM for DMAPP.
Deletion of the signalling molecule synthase ScbA has pleiotropic effects on secondary metabolite biosynthesis, morphological differentiation and primary metabolism in Streptomyces coelicolor A3(2)
2010-12-08

Summary Streptomycetes have high biotechnological relevance as producers of diverse metabolites widely used in medical and agricultural applications. The biosynthesis of these metabolites is controlled by signalling molecules, γ‐butyrolactones, that act as bacterial hormones. In Streptomyces coelicolor , a group of signalling molecules called SCBs ( S . c oelicolor b utanolides) regulates production of the pigmented antibiotics c oelicolor p oly k etide (CPK), actinorhodin and undecylprodigiosin. The γ‐butyrolactone synthase ScbA is responsible for the biosynthesis of SCBs. Here we show the results of a genome‐wide transcriptome analysis of a scbA deletion mutant prior to and during the transition to antibiotic production. We report a strong perturbation in the expression of three pigmented antibiotic clusters in the mutant throughout the growth curve, thus providing a molecular explanation for the antibiotic phenotype observed previously. Our study also revealed, for the first time, that the secondary metabolite cluster responsible for synthesis of the siderophore desferrioxamine is under the control of SCB signalling. Moreover, expression of the genes encoding enzymes for primary metabolism pathways, which supply antibiotic precursors and genes for morphological differentiation, was found shifted earlier in time in the mutant. In conclusion, our time series analysis demonstrates new details of the regulatory effects of the γ‐butyrolactone system in Streptomyces .
Effects of Magnetic Resonance Imaging Contrast Agents on Human Umbilical Vein Endothelial Cells and Evaluation of Magnetic Resonance Imaging Contrast Media-Triggered Transforming Growth Factor-Beta Induction in Dermal Fibroblasts (HSF) as a Model for Nephrogenic Systemic Fibrosis
2010-12-08

After 24 hours of incubation with Omniscan and Teslascan (10× and 20× concentration), considerable short-term antiproliferative effects in HUVECs were observed. HSF cells (20× concentration) showed a reduction of TGF-β for Resovist and Teslascan directly after incubation, whereas TGF-β levels in HSF cells were slightly reduced for all CM 8 days after incubation. Therefore, TGF-β-mediated proliferative effects on fibroblasts or on collagen synthesis potentially leading to nephrogenic systemic fibrosis may mainly be triggered by tissue monocytes and macrophages in the peripheral blood instead of dermal fibroblasts.
Serum- and glucocorticoid-inducible kinase 1 (SGK1) controls Notch1 signaling by downregulation of protein stability through Fbw7 ubiquitin ligase
2010-12-09

Notch is a transmembrane protein that acts as a transcriptional factor in the Notch signaling pathway for cell survival, cell death and cell differentiation. Notch1 and Fbw7 mutations both lead the activation of the Notch1 pathway and are found in the majority of patients with the leukemia T-ALL. However, little is known about the mechanisms and regulators that are responsible for attenuating the Notch signaling pathway through Fbw7. Here, we report that the serum- and glucocorticoid-inducible protein kinase SGK1 remarkably reduced the protein stability of the active form of Notch1 through Fbw7. The protein level and transcriptional activity of the Notch1 intracellular domain (Notch1-IC) were higher in SGK1-deficient cells than in SGK1 wild-type cells. Notch1-IC was able to form a trimeric complex with Fbw7 and SGK1, thereby SGK1 enhanced the protein degradation of Notch1-IC via a Fbw7-dependent proteasomal pathway. Furthermore, activated SGK1 phosphorylated Fbw7 at serine 227, an effect inducing Notch1-IC protein degradation and ubiquitylation. Moreover, accumulated dexamethasone-induced SGK1 facilitated the degradation of Notch1-IC through phosphorylation of Fbw7. Together our results suggest that SGK1 inhibits the Notch1 signaling pathway via phosphorylation of Fbw7.