julilili42/papers huggingface dataset:
Natural killer cells are required for accelerated type 1 diabetes driven by interferon-β
2008-01-09

Summary The destruction of β cells by the islet infiltrating lymphocytes causes type 1 diabetes. Transgenic mice models expressing interferon (IFN)-β in β cells, in the non-obese diabetic (NOD) strain and in a diabetes-free, major histocompatibility complex-matched, homologous strain, the non-obese resistant (NOR) mice, developed accelerated type 1 diabetes after 3 weeks of age. Our aim was to determine if natural killer (NK) cells could affect the acceleration of the disease. We determined the amount of NK cells in the pancreas, spleen and lymph nodes from NOD rat insulin promoter (RIP)-IFN-β mice. Pancreatic cytokines were assessed by quantitative real-time polymerase chain reaction and protein arrays. To confirm the relevance of NK cells in the acceleration of autoimmune diabetes this subset was depleted with anti-asialo GM1 antibodies. An increase of intrapancreatic NK cells characterized the accelerated onset of diabetes both in NOD and NOR RIP-IFN-β transgenic models. Cytokines involved in NK function and migration were found to be hyperexpressed in the pancreas from accelerated diabetic mice. Interestingly, the depletion of NK cells in vivo abolished completely the acceleration of diabetes. NK cells connect innate to adaptive immunity and might play a role in autoimmunity. We report here that NK cells are required critically in the pancreas for accelerated diabetes. This model links inflammation to acceleration of β cell-specific autoimmunity mediated by NK cells.
ChemInform Abstract: Synthesis of Nitrogen‐Containing Spirocyclic Scaffolds via Aminoallylation/RCM Sequence.
2008-01-09

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.
ChemInform Abstract: New Aminocoumarin Antibiotics Derived from 4‐Hydroxycinnamic Acid Are Formed After Heterologous Expression of a Modified Clorobiocin Biosynthetic Gene Cluster.
2008-01-09

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.
UL74 of Human Cytomegalovirus Contributes to Virus Release by Promoting Secondary Envelopment of Virions
2008-01-10

ABSTRACT The glycoprotein (g) complex gH/gL represents an essential part of the herpesvirus fusion machinery mediating entry of cell-free virions and cell-associated viral spread. In some herpesviruses additional proteins are associated with gH/gL contributing to the cell tropism of the respective virus. Human cytomegalovirus (HCMV) gH/gL forms complexes with either gO (UL74) or proteins of the UL128-131A gene locus. While a contribution of UL128-131A to endothelial cell tropism is known, the role of gO is less clear. We studied the role of gH/gL-associated proteins in HCMV replication in human foreskin fibroblasts (HFF) and human umbilical vein endothelial cells (HUVEC). Deletions of UL74 alone or in combination with mutations of the UL128-131A gene region were introduced into bacterial artificial chromosome vectors derived from the endotheliotropic strain TB40/E. Deletion of UL74 caused a profound defect regarding virus release from infected HFF and HUVEC. Large numbers of capsids accumulated in the cytoplasm of infected HFF but failed to acquire an envelope. Clear cell type differences were observed in the cell-associated spread of the UL74-defective virus. In HFF, focal growth was severely impaired, whereas it was normal in HUVEC. Deletion of UL131A abolished focal growth in endothelial cells. UL74/UL128-131A dual mutants showed severely impaired reconstitution efficiency. Our data suggest that gO plays a critical role in secondary envelopment and release of cell-free virions independent of the cell type but affects cell-associated growth specifically in HFF, whereas UL128-131A contributes to cell-associated spread in HFF and HUVEC.
Glomus Tumor of the Stomach Simulating a Gastrointestinal Stromal Tumor: A Case Report and Review of Literature
2008-01-10

Glomus tumor is an infrequent and in most cases benign mesenchymal neoplasia which affects subcutaneous/submucosal tissue and occurs in the gastrointestinal tract, solid organs (e.g. liver, kidney) and the extremities. Visceral glomus tumor of the stomach generally presents with non-specific epigastric pain, loss of appetite and GI bleeding (melaena), often without haemodynamic instability. Macroscopic appearances on upper GI endoscopy are non-diagnostic. Endosonographic appearances are generally heterogenous and poorly-reflective, hence fail to differentiate glomus tumor from other potential diagnoses. Histological confirmation of the diagnosis is only possible when a fine needle biopsy is inclusive of abnormal tissue. These difficulties in diagnosis mean that in many cases, only immunohistochemical analysis of surgically resected tissue can distinguish glomus tumor from several possible differentials. Therefore, endoscopically-assisted laparoscopic curative wedge-resection of a lesion suspicious for glomus tumor of the upper gastrointestinal tract must be considered first-line in terms of a combined investigative and curative approach.
Dependence of nucleon properties on pseudoscalar meson masses
2008-01-10

We discuss the sensitivity of nucleon properties (mass, magnetic moments and electromagnetic form factors) on the variation of the pseudoscalar meson masses in the context of the perturbative chiral quark model. The obtained results are compared to data and other theoretical predictions.
Imaging Nanometre‐Sized Hot Spots on Smooth Au Films with High‐Resolution Tip‐Enhanced Luminescence and Raman Near‐Field Optical Microscopy
2008-01-11

Abstract A novel near‐field optical microscope based on a parabolic mirror is used for recording high‐resolution tip‐enhanced photoluminescence (PL) and Raman images with unprecedented sensitivity and contrast. The measurements reveal small islands on the Au surface with dimensions of only a few nanometres with locally enhanced Au PL. These islands appear as nanometre‐sized hot spots in tip‐enhanced Raman microscopy when benzotriazole molecules adsorbed on the Au surface serve as local sensors for the optical field. The spectra show that localized plasmons are the cause of both the locally enhanced Au PL and enhanced Raman scattering. This finding suggests that the dispersive background in the surface‐enhanced Raman spectra can be explained simply by the enhanced Au PL in the gap. Furthermore, our results show that the surface flatness must be better than 1 nm, to provide an optically homogeneous substrate for near‐field enhanced PL and Raman spectroscopy.
Spectral Versatility of Single Reef Coral Fluorescent Proteins Detected by Spectrally‐Resolved Single Molecule Spectroscopy
2008-01-11

Abstract We use spectrally‐resolved room temperature single molecule spectroscopy to yield insights into the occurrence and dynamics of spectral forms of single tetramers of DsRed and its variants DsRed2, Fluorescent Timer, DsRed_N42H and AG4. The red‐emitting chromophore in DsRed and all studied variants readily converts into a high quantum efficiency super‐red emitting form. We propose the existence of two super‐red forms of different quantum efficiencies. The observed emission from the green‐emitting chromophore is consistent with bulk spectroscopy. We further observe distinct new spectral forms from each variant, which we attribute to a photoinduced chemical reaction leading to a truncated form of the red‐emitting chromophore analogous to the chromophore in the visible fluorescent protein zFP538. Our results have implications for the accurate interpretation of biological and biochemical processes illuminated by fluorescent proteins as well as for choosing appropriate experimental configurations.
Hepatic selenoprotein P (SePP) expression restores selenium transport and prevents infertility and motor-incoordination in Sepp-knockout mice
2008-01-15

SePP (selenoprotein P) is central for selenium transport and distribution. Targeted inactivation of the Sepp gene in mice leads to reduced selenium content in plasma, kidney, testis and brain. Accordingly, activities of selenoenzymes are reduced in Sepp−/− organs. Male Sepp−/− mice are infertile. Unlike selenium deficiency, Sepp deficiency leads to neurological impairment with ataxia and seizures. Hepatocyte-specific inactivation of selenoprotein biosynthesis reduces plasma and kidney selenium levels similarly to Sepp−/− mice, but does not result in neurological impairment, suggesting a physiological role of locally expressed SePP in the brain. In an attempt to define the role of liver-derived circulating SePP in contrast with locally expressed SePP, we generated Sepp−/− mice with transgenic expression of human SePP under control of a hepatocyte-specific transthyretin promoter. Secreted human SePP was immunologically detectable in serum from SEPP1-transgenic mice. Selenium content and selenoenzyme activities in serum, kidney, testis and brain of Sepp−/−;SEPP1 (SEPP1-transgenic Sepp−/−) mice were increased compared with Sepp−/− controls. When a selenium-adequate diet (0.16-0.2 mg/kg of body weight) was fed to the mice, liver-specific expression of SEPP1 rescued the neurological defects of Sepp−/− mice and rendered Sepp−/− males fertile. When fed on a low-selenium diet (0.06 mg/kg of body weight), Sepp−/−;SEPP1 mice survived 4 weeks longer than Sepp−/− mice, but ultimately developed the neurodegenerative phenotype. These results indicate that plasma SePP derived from hepatocytes is the main transport form of selenium supporting the kidney, testis and brain. Nevertheless, local Sepp expression is required to maintain selenium content in selenium-privileged tissues such as brain and testis during dietary selenium restriction.
Head and eye movements and the role of memory limitations in a visual search paradigm
2008-01-15

The image information guiding visual behavior is acquired and maintained in an interplay of gaze shifts and visual short-term memory (VSTM). If storage capacity of VSTM is exhausted, gaze shifts can be used to regain information not currently represented in memory. By varying the separation between relevant image regions, S. Inamdar and M. Pomplun (2003) demonstrated a trade-off between VSTM storage and gaze shifts, which were performed as pure eye movements, that is, without a head movement component. Here we extend this paradigm to larger gaze shifts involving both eye and head movements. We use a comparative visual search paradigm with two relevant image regions and region separation as independent variable. Image regions were defined by two cupboards displaying colored geometrical objects in roughly equal arrangements. Subjects were asked to find differences in the arrangement of the objects in the two cupboards. Cupboard separation was varied between 30 degrees and 120 degrees . Images were presented with two projectors on a 150 degrees x 70 degrees curved screen. Head and eye movements were simultaneously recorded with an ART head tracker and an ASL mobile eye tracker, respectively. In the large separation conditions, the number of gaze shifts between the two cupboards was reduced, while fixation duration increased. Furthermore, the head movement proportions negatively correlated with the number of gaze shifts and positively correlated with fixation duration. We conclude that the visual system uses increased VSTM involvement to avoid gaze movements and in particular movements of the head. Scan path analysis revealed two subject-specific strategies (encode left, compare right, and vice versa), which were consistently used in all separation conditions.
EVOLUTIONARY LINKS BETWEEN REPRODUCTIVE MORPHOLOGY, ECOLOGY AND MATING BEHAVIOR IN OPISTHOBRANCH GASTROPODS
2008-01-15

Sexual coevolution in morphological and behavioral traits has rarely been studied. Using phylogenetic analyses, we explore relationships between sexual characters based on a new molecular phylogeny of 33 opisthobranch taxa (Aglajidae and Gastropteridae). Our measurements of these simultaneous hermaphrodites include male and female reproductive anatomy, mating behavior, and spatial gregariousness. After phylogenetic correction, we found evidence for correlated evolution between male and female reproductive organs such as the size of the seminal fluid producing prostate gland and that of the sperm digesting bursa copulatrix. Our findings suggest that reproductive trait variation is mediated by sexual coevolution, where putatively manipulative male organs evolved in association with female organs involved in sperm selection. Furthermore, low gregariousness was associated with long, reciprocal copulations. We interpret this result as an adaptation to infrequent mate encounters, where it pays to mate longer with and presumably transfer more sperm to a rare partner. Several complex reproductive traits were repeatedly gained or lost across our phylogeny. This pattern is consistent with a scenario in which sexual selection generates dynamic coevolutionary cycles similar to those expected under sexual antagonism. We finally outline approaches for experimentally assessing the proposed functional links that underlie the evolutionary correlations revealed by our study.
Structural modulations in Bi2Te3
2008-01-15

Bi 2 Te 3 is known for its large thermopower, a low thermal conductivity, and thereby a large thermoelectric figure of merit ZT at room temperature. Particularly, the low thermal conductivity is attributed to a high structural disorder. Electron probe microanalysis, transmission electron microscopy (TEM), and energy dispersive x-ray spectrometry in the TEM were applied on n-type Bi2(Te,Se)3 and p-type (Bi,Sb)2Te3 bulk materials for structural and chemical analysis. Significant variations in stoichiometry were found on the micrometer scale. Bulk materials showed a texture, grain sizes of 1−10 μm, and dislocations in the basal plane with a density of 109 cm−2 having a high mobility at room temperature. A structural modulation [natural nanostructure (nns)] was found on the nanometer scale. This nns was also observed in Bi2Te3 thin films and Bi2Te3/Bi2(Te,Se)3 superlattices and turned out to be of general character for Bi2Te3 materials. The nns was analyzed in detail by stereomicroscopy in the TEM and by image simulation. The nns was found to be a pure sinusoidal displacement field with (i) a displacement vector parallel to ⟨5,−5,1⟩ and an amplitude of about 10 pm and (ii) a wave vector parallel to {1,0,10} and a wavelength of 10 nm. Bi2Te3 samples from different batches produced under similar conditions showed different characteristics with respect to the nns: none, one, or two superimposed nns were observed. The nns is present in all parts of the sample with the same orientation. The formation of the nns is either bound to a certain stoichiometry range or to the thermal history of a sample and is related to the tendency of Te compounds to form amorphous phases. An ordered network of dislocations a few nanometers apart and chemical fluctuations on the nanometer scale as origins of the nns were ruled out. The displacement field of the nns is superimposed to the average structure and should significantly affect the thermoelectric properties. Particularly, the lattice thermal conductivity should be decreased due to phonon scattering on the sinusoidal strain field of the nns. Also, the nns should yield a one-dimensional or zero-dimensional behavior of the phonons and anisotropic transport coefficients in the basal plane.
Cloning and sequencing of a highly productive, endotheliotropic virus strain derived from human cytomegalovirus TB40/E
2008-01-16

Human cytomegalovirus (HCMV) strain TB40/E, replicates efficiently, exhibits a broad cell tropism and is widely used for infection of endothelial cells and monocyte-derived cells yet has not been available in a phenotypically homogeneous form compatible with genetic analysis. To overcome this problem, we cloned the TB40/E strain into a bacterial artificial chromosome (BAC) vector. Both highly endotheliotropic and poorly endotheliotropic virus clones, representing three distinct restriction fragment patterns, were reconstituted after transfection of BAC clones derived from previously plaque-purified strain TB40/E. For one of the highly endotheliotropic clones, TB40-BAC4, we provide the genome sequence. Two BACs with identical restriction fragment patterns but different cell tropism were further analysed in the UL128-UL131A gene region. Sequence analysis revealed one coding-relevant adenine insertion at position 332 of UL128 in the BAC of the poorly endotheliotropic virus, which caused a frameshift in the C-terminal part of the coding sequence. Removal of this insertion by markerless mutagenesis restored the highly endotheliotropic phenotype, indicating that the loss of endothelial cell tropism was caused by this insertion. In conclusion, HCMV strain TB40/E, which combines the high endothelial cell tropism of a clinical isolate with the high titre growth of a cell culture adapted strain, is now available as a BAC clone suitable for genetic engineering. The results also suggest BAC cloning as a suitable method for selection of genetically defined virus clones.
Detection of Uterine MMG Contractions Using a Multiple Change Point Estimator and the K-Means Cluster Algorithm
2008-01-16

We propose a single channel two-stage time-segment discriminator of uterine magnetomyogram (MMG) contractions during pregnancy. We assume that the preprocessed signals are piecewise stationary having distribution in a common family with a fixed number of parameters. Therefore, at the first stage, we propose a model-based segmentation procedure, which detects multiple change-points in the parameters of a piecewise constant time-varying autoregressive model using a robust formulation of the Schwarz information criterion (SIC) and a binary search approach. In particular, we propose a test statistic that depends on the SIC, derive its asymptotic distribution, and obtain closed-form optimal detection thresholds in the sense of the Neyman-Pearson criterion; therefore, we control the probability of false alarm and maximize the probability of change-point detection in each stage of the binary search algorithm. We compute and evaluate the relative energy variation [root mean squares (RMS)] and the dominant frequency component [first order zero crossing (FOZC)] in discriminating between time segments with and without contractions. The former consistently detects a time segment with contractions. Thus, at the second stage, we apply a nonsupervised K-means cluster algorithm to classify the detected time segments using the RMS values. We apply our detection algorithm to real MMG records obtained from ten patients admitted to the hospital for contractions with gestational ages between 31 and 40 weeks. We evaluate the performance of our detection algorithm in computing the detection and false alarm rate, respectively, using as a reference the patients' feedback. We also analyze the fusion of the decision signals from all the sensors as in the parallel distributed detection approach.
Efficient in vitro generation of adult multipotent cells from mobilized peripheral blood CD133+ cells
2008-01-16

Abstract. Objectives : To generate non‐haematopoietic tissues from mobilized haematopoietic CD133 + stem cells. Materials and methods : Mobilized peripheral blood CD133 + cells from adult healthy donors were used. In vitro ability of highly enriched CD133 + cells from mobilized peripheral blood to generate multipotent cells, and their potential to give rise to cells with characteristics of neuroectoderm, endoderm and mesoderm layers was investigated. Results : We found that a recently identified population of CD45 + adherent cells generated in vitro after culture of highly purified CD133 + cells for 3–5 weeks with Flt3/Flk2 ligand and interleukin‐6 can, in presence of the appropriate microenvironmental cues, differentiate into neural progenitor‐like cells (NPLCs), hepatocyte‐like cells and skeletal muscle‐like cells. We have termed them to be adult multipotent haematopoietic cells (AMHCs). AMHC‐derived NPLCs expressed morphological, phenotypic and molecular markers associated with primary neural progenitor cells. They can differentiate into astrocyte‐like cells, neuronal‐like cells and oligodendrocyte‐like cells. Moreover, AMHC‐derived NPLCs produced 3,4‐dihydrophenylalanine and dopamine and expressed voltage‐activated ion channels, suggesting their functional maturation. In addition, AMHC‐derived hepatocyte‐like cells and skeletal muscle‐like cells, showed typical morphological features and expressed primary tissue‐associated proteins. Conclusion : Our data demonstrate that AMHCs may therefore serve as a novel source of adult multipotent cells for autologous replacement cell therapies.
Hydrodynamic theory of polydisperse chain-forming ferrofluids
2008-01-17

The larger magnetic particles in ferrofluids are known to form chains, causing the fluid to display non-Newtonian behavior. In this paper, a generalization of the familiar ferrofluid dynamics by Shliomis is shown capable of realistically accounting for these fluids. The modification consists of identifying the relaxing magnetization as that of the chain-forming particles, while accounting for the free magnetic particles by dissipative terms in the Maxwell equations.
Efficacy of a Helicase-Primase Inhibitor in Animal Models of Ocular Herpes Simplex Virus Type 1 Infection
2008-01-17

BAY 57-1293 may be more effective than valacyclovir, without the cytotoxicity or potential healing retardation seen with trifluridine. Oral BAY 57-1293 may be a substitute for eye drops as an effective treatment for herpetic keratitis and might be useful in treating stromal keratitis and iritis, as well as preventing recurrences of ocular herpes.
Nonaxisymmetric oscillations of differentially rotating relativistic stars
2008-01-17

Non-axisymmetric oscillations of differentially rotating stars are studied using both slow rotation and Cowling approximation. The equilibrium stellar models are relativistic polytropes where differential rotation is described by the relativistic j-constant rotation law. The oscillation spectrum is studied versus three main parameters: the stellar compactness M/R, the degree of differential rotation A and the number of maximun couplings [script-I]max. It is shown that the rotational splitting of the non-axisymmetric modes is strongly enhached by increasing the compactness of the star and the degree of differential rotation. Finally, we investigate the relation between the fundamental quadrupole mode and the corotation band of differentially rotating stars.