julilili42/papers huggingface dataset:
Dynamic Maps for Long-Term Operation of Mobile Service Robots
2005-06-08

&lt;p&gt;This paper introduces a dynamic map for mobile robots that adapts continuously over time. It resolves the stability plasticity dilemma (the tradeoff between adaptation to new patterns and preservation of old patterns) by representing the environment over multiple time scales simultaneously (five in our experiments). A sample-based representation is proposed, where older memories fade at different rates depending on the time scale. Robust statistics are used to interpret the samples. It is shown that this approach can track both stationary and non-stationary elements of the environment, covering the full spectrum of variations from moving objects to structural changes. The method was evaluated in a five-week experiment in a real dynamic environment. Experimental results show that the resulting map is stable, improves its quality over time and adapts to changes.&lt;/p&gt;
Clonal Heterogeneity in Growth Kinetics of CD34+CD38−Human Cord Blood Cells In Vitro Is Correlated with Gene Expression Pattern and Telomere Length
2005-06-08

Human hematopoietic stem cells (HSCs) are characterized by an extensive proliferative capacity that decreases from fetal liver to cord blood (CB) to adult bone marrow. In previous studies, it was demonstrated that the proliferative capacity of individual CD34+CD38- HSC clones is correlated with their growth kinetics in vitro and that HSC turnover in vivo can be estimated by telomere-length measurements. The present study was aimed at the characterization of the clonal composition of CD34+CD38- human umbilical CB cells in terms of growth kinetics, telomere length, and gene expression profile. For this purpose, individual CD34+CD38- CB cells were sorted into 96-well plates containing serum-free medium supplemented with six growth factors. During expansion, cell numbers in each individual well were scored in 3-day intervals. Once sufficient cell numbers were achieved, telomere length was measured by flow fluorescence in situ hybridization (flow FISH). In a second set of experiments, gene expression and colony-forming capacity were analyzed in slowly growing clones as compared with fast-growing clones, using linear amplification and oligonucleotide microarrays (HG-U133A; Affymetrix). Individual CD34+CD38- cells from CB displayed an extensive functional heterogeneity in growth kinetics. Among highly proliferative clones, the most slowly growing clones were characterized by the longest telomeres. Furthermore, significant differences in gene expression were detected between slow- and fast-growing clones, whereas no significant difference in colony-forming capacity was observed. These data provide further evidence for a functional hierarchy in the human HSC compartment and suggest a link between telomere length and proliferation capacity of individual HSC clones.
The fragile X tremor ataxia syndrome in the differential diagnosis of multiple system atrophy: data from the EMSA Study Group
2005-06-09

The recent identification of fragile X-associated tremor ataxia syndrome (FXTAS) associated with premutations in the FMR1 gene and the possibility of clinical overlap with multiple system atrophy (MSA) has raised important questions, such as whether genetic testing for FXTAS should be performed routinely in MSA and whether positive cases might affect the specificity of current MSA diagnostic criteria. We genotyped 507 patients with clinically diagnosed or pathologically proven MSA for FMR1 repeat length. Among the 426 clinically diagnosed cases, we identified four patients carrying FMR1 premutations (0.94%). Within the subgroup of patients with probable MSA-C, three of 76 patients (3.95%) carried premutations. We identified no premutation carriers among 81 patients with pathologically proven MSA and only one carrier among 622 controls (0.16%). Our results suggest that, with proper application of current diagnostic criteria, FXTAS is very unlikely to be confused with MSA. However, slowly progressive disease or predominant tremor are useful red flags and should prompt the consideration of FXTAS. On the basis of our data, the EMSA Study Group does not recommend routine FMR1 genotyping in typical MSA patients.
Lessons from the bone marrow: how malignant glioma cells attract adult haematopoietic progenitor cells
2005-06-09

Stem and progenitor cells (PCs) of various lineages have become attractive vehicles to improve therapeutic gene delivery to cancers, notably glioblastoma. Here we report that adult human and murine haematopoietic PCs display a tropism for intracerebral gliomas but not for normal brain tissue in mice. Organotypic hippocampal slice culture and spheroid confrontation assays confirm a directed PC migration towards glioma cells ex vivo and in vitro. RNA interference-mediated disruption of transforming growth factor beta (TGF-beta) synthesis by the glioma cells strongly inhibits PC migration. We delineate a CXC chemokine ligand (CXCL) 12-dependent pathway of TGF-beta-induced PC migration that is facilitated by MMP-9-mediated stem cell factor cleavage in vitro. Moreover, neutralizing antibodies to CXCL12 strongly reduce PC homing to experimental gliomas in vivo. Thus, we define here the molecular mechanism underlying the glioma tropism of the probably most easily accessible PC population suitable for cancer therapy, that is, adult haematopoietic PC.
Synthesis of the Fully Functionalized Core Structure of the Antibiotic Abyssomicin C
2005-06-09

[reaction: see text] The fully functionalized core structure 23 of abyssomicin C (6) containing an oxabicyclooctane ring and a tetronate was prepared via a Diels-Alder approach. After hydroxylation of lactone 10 to the alpha-hydroxylactone 12, lactone opening led to the hydroxy ester 16. A directed epoxidation furnished the desired syn-epoxide 20. Acetylation of the tertiary hydroxyl group, followed by intramolecular Claisen condensation, gave directly the core structure 23.
Nonlinear Optical Properties of Tetrapyrazinoporphyrazinato Indium Chloride Complexes Due to Excited-State Absorption Processes
2005-06-10

The multiphoton absorption properties of the axially substituted tetrapyrazinotetraazaporphyrinato complex Pyz(4)TAPInCl (1) are reported and interpreted. In particular, the nonlinear optical transmission of the complex and the excited states involved in the nonlinear absorption have been determined at the frequency of the second harmonic generation of a Nd:YAG laser in the nanosecond time regime. Pyz(4)TAPInCl has an excited-state absorption cross section larger than its ground state in the 460-540 nm spectral region, and it shows an optical limiting (OL) behavior at 532 nm, which derives from a sequential two-photon absorption with a larger absorption cross section of the excited triplet state with respect to the ground state. It results that the absorption cross section of 1 in the excited triplet state is 7.8 x 10(-18) cm(2) vs 0.9 x 10(-18) cm(2) of the ground state at the wavelength of OL analysis.
Proliferation and progesterone receptor status in benign meningiomas are not age dependent
2005-06-10

Abstract BACKGROUND Some authors have suggested that the biology of meningiomas differs according to a patient's age. Proliferation, vascularity, and hormonal status in meningiomas can be used to describe changes during aging. In the current study, proliferation activity with the Ki‐67/MIB‐1 antibody was evaluated by immunohistochemistry in meningioma tissue specimens from young and elderly patients. METHODS Over the past 25 years, tissue samples from 1766 patients with meningiomas were evaluated. Of these, 588 tumor specimens from 554 patients who underwent surgery between 1990 and 2000 were evaluated immunohistochemically. The proliferation index (LI) and progesterone receptor (PR) in meningiomas were quantitatively estimated in elderly (age ≥ 70 years) and young patients (age &lt; 70 years). Patients' charts including surgical records, discharge letters, pathology reports, and imaging studies were reviewed. Correlations with histologic subtype, disease recurrence‐free survival, resection grade, location, size, vascularity, and tumor calcification were calculated as well. Only patients with a well documented follow‐up were included in the statistical evaluation ( n = 385). RESULTS Compared with the young group of 344 patients with meningioma (age &lt; 70 years; mean age, 51.9 years; range, 18–69 years), the elderly population (age ≥ 70 years; n = 41; mean age, 74.9 years; range, 70–88 years) showed a male‐to‐female ratio of 3.2: 1. Both groups had an identical median Ki‐67 LI of 3.0% and a PR status of 56.1% versus 58.4 %. No statistically significant differences in disease recurrence‐free survival could be found in the two groups. CONCLUSIONS Proliferation rates and PR status in benign intracranial meningiomas did not appear to be age dependent. Cancer 2005. © 2005 American Cancer Society.
A Framework for Visualization of Microarray Data and Integrated Meta Information
2005-06-10

We have developed a methodology that allows integration of microarray data and meta information within a visualization in order to guide the investigator during data exploration and analysis. A simple mathematical framework is introduced that uses scoring functions to map meta information to relevance ratings of genes. To explore the potential of this framework we extended the traditional heatmap with new features to graphically represent the relevance ratings. These ratings are visualized by an additional color gradient, by scaling the vertical height of matrix rows, by rearranging rows or by inserting new columns into the heatmap. This visualization is called an enhanced heatmap. We have applied our approach to microarray data of the Saccharomyces cerevisiae cell cycle, complemented with supplemental data that we both derived from the microarray data itself and retrieved from public databases. Using these data we demonstrate how this visualization concept can be efficiently used to identify certain features of genes and to detect inconsistencies in the data. Thus, the investigator has the possibility to get an overview of data from various sources and at the same time can gain a deeper insight into the structure of the combined data. The concept is not restricted to heatmaps, and can be used to extend further visualization techniques, such as profile plots. We found that our method is a powerful tool to integrate supplemental data into microarray visualizations and that it increases the efficiency of visual data exploration, which is a fundamental part of microarray data analyses.
The Tarantula Toxin Psalmotoxin 1 Inhibits Acid-sensing Ion Channel (ASIC) 1a by Increasing Its Apparent H+ Affinity
2005-06-13

Acid-sensing ion channels (ASICs) are ion channels activated by extracellular protons. They are involved in higher brain functions and perception of pain, taste, and mechanical stimuli. Homomeric ASIC1a is potently inhibited by the tarantula toxin psalmotoxin 1. The mechanism of this inhibition is unknown. Here we show that psalmotoxin 1 inhibits ASIC1a by a unique mechanism: the toxin increases the apparent affinity for H+ of ASIC1a. Since ASIC1a is activated by H+ concentrations that are only slightly larger than the resting H+ concentration, this increase in H+ affinity is sufficient to shift ASIC1a channels into the desensitized state. As activation of ASIC1a has recently been linked to neurodegeneration associated with stroke, our results suggest chronic desensitization of ASIC1a by a slight increase of its H+ affinity as a possible way of therapeutic intervention in stroke.
Treatment of small plaque parapsoriasis with narrow-band (311 nm) ultraviolet B: a retrospective study
2005-06-13

Narrow band (311 nm) ultraviolet B (NB-UVB) has been shown to be a safe and effective treatment for psoriasis and other inflammatory skin diseases. We have therefore employed NB-UVB in the treatment of small plaque parapsoriasis (SPP) since 1996. All patients (16/16) responded with complete remission of the disease after a mean number of 32.8 exposures and a mean total dose of 35.4 J/cm2. Unwanted side-effects were rare (3.3%) and always mild. Relapse of the disease occurred after an average of 29 weeks in those patients who came for follow-up visits. Therefore, NB-UVB is an effective, comparably safe and convenient alternative to psoralen and ultraviolet A therapy or other treatment modalities in the suppression of SPP.
Image quality and diagnostic accuracy of non-invasive coronary imaging with 16 detector slice spiral computed tomography with 188 ms temporal resolution
2005-06-14

Objective: To evaluate image quality and clinical accuracy in detecting coronary artery lesions with a new multidetector spiral computed tomography (MDCT) generation with 16 detector slices and a temporal resolution of 188 ms. Methods: 124 consecutive patients scheduled for invasive coronary angiography (ICA) were additionally studied by MDCT (Sensation 16 Speed 4D). MDCTs were analysed with regard to image quality and presence of coronary artery lesions. The results were compared with ICA. Results: 120 of 124 scans were successful. The image quality of all remaining 120 scans was sufficient (mean (SD) heart rate 64.2 (9.8) beats/min, range 43–95). The mean calcium mass was 167 (223) mg (range 0–1038). Thirteen coronary segments were evaluated for each patient (1560 segments in total). Image quality was graded as follows: excellent, 422 (27.1%) segments; good, 540 (34.6%) segments; moderate, 277 (17.7%) segments; heavily calcified, 215 (13.8%) segments; and blurred, 106 (6.8%) segments. ICA detected 359 lesions with a diameter stenosis &gt; 50% and MDCT detected 304 of 359 (85%). Sensitivity, specificity, and positive and negative predictive values were 85%, 98%, 91%, and 96%, respectively. The correct clinical diagnosis (presence or absence of at least one stenosis &gt; 50%) was obtained for 110 of 120 (92%) patients. Conclusions: MDCT image quality can be further improved with 16 slices and faster gantry rotation time. These results in an unselected population underline the potential of MDCT to become a non-invasive diagnostic alternative, especially for the exclusion of coronary artery disease, in the near future.
Deficiency of Dermcidin-Derived Antimicrobial Peptides in Sweat of Patients with Atopic Dermatitis Correlates with an Impaired Innate Defense of Human Skin In Vivo
2005-06-15

Abstract Antimicrobial peptides are an integral part of the epithelial innate defense system. Dermcidin (DCD) is a recently discovered antimicrobial peptide with a broad spectrum of activity. It is constitutively expressed in human eccrine sweat glands and secreted into sweat. Patients with atopic dermatitis (AD) have recurrent bacterial or viral skin infections and pronounced colonization with Staphylococcus aureus. We hypothesized that patients with AD have a reduced amount of DCD peptides in sweat contributing to the compromised constitutive innate skin defense. Therefore, we performed semiquantitative and quantitative analyses of DCD peptides in sweat of AD patients and healthy subjects using surface-enhanced laser desorption ionization time-of-flight mass spectrometry and ELISA. The data indicate that the amount of several DCD-derived peptides in sweat of patients with AD is significantly reduced. Furthermore, compared with atopic patients without previous infectious complications, AD patients with a history of bacterial and viral skin infections were found to have significantly less DCD-1 and DCD-1L in their sweat. To analyze whether the reduced amount of DCD in sweat of AD patients correlates with a decreased innate defense, we determined the antimicrobial activity of sweat in vivo. We showed that in healthy subjects, sweating leads to a reduction of viable bacteria on the skin surface, but this does not occur in patients with AD. These data indicate that reduced expression of DCD in sweat of patients with AD may contribute to the high susceptibility of these patients to skin infections and altered skin colonization.
Electronic properties of interfaces between different sexithiophenes and gold
2005-06-15

We present a photoemission study of the interface between sexithiophene and polycrystalline gold. Two different sexithiophenes have been investigated—α-6T and a derivative of α-6T(ββ′-DH6T) with additionally attached alkane chains at thiophene rings, which increases its solubility and allows application in solution-based processes. We find an interface dipole of 1.2 eV and we observe chemical interactions for both sexithiophenes. Special attention has been paid to the possible influence of the chemical modification on the electronic properties of the material itself and its influence on the interface properties with gold. In addition, we discuss the differences in the electronic structure of vacuum-sublimated and spin-coated films of ββ′-DH6T. We find indications for better ordered films applying the solution-based process and the spin-coating procedure leads to oxidation of the organic film.
Fabrication and characterization of multiterminal superconductor-insulator-normal metal-insulator-superconductor Josephson devices
2005-06-15

We report the fabrication and basic characteristics of a multiterminal SINIS device which has electrical leads connected to the middle N layer; here S,I, and N denote a superconductor (Nb), an insulator (AlOx), and a normal metal (Al), respectively. We studied the behavior of the Josephson current through all layers on an injection current passing through one of the individual (NIS) junctions and along the N layer, as well as the influence of the injection current from one junction on the current–voltage characteristic of the other. In the latter case, a current gain and power gain, and good isolation between the input and output were observed.
Loss of function mutations in the gene encoding Omi/HtrA2 in Parkinson's disease
2005-06-16

Recently targeted disruption of Omi/HtrA2 has been found to cause neurodegeneration and a parkinsonian phenotype in mice. Using a candidate gene approach, we performed a mutation screening of the Omi/HtrA2 gene in German Parkinson's disease (PD) patients. In four patients, we identified a novel heterozygous G399S mutation, which was absent in healthy controls. Moreover, we identified a novel A141S polymorphism that was associated with PD (P<0.05). Both mutations resulted in defective activation of the protease activity of Omi/HtrA2. Immunohistochemistry and functional analysis in stably transfected cells revealed that S399 mutant Omi/HtrA2 and to a lesser extent, the risk allele of the A141S polymorphism induced mitochondrial dysfunction associated with altered mitochondrial morphology. Cells overexpressing S399 mutant Omi/HtrA2 were more susceptible to stress-induced cell death than wild-type. On the basis of functional genomics, our results provide a novel link between mitochondrial dysfunction and neurodegeneration in PD.
Acute subdural haematoma without subarachnoid haemorrhage caused by rupture of an internal carotid artery bifurcation aneurysm: case report and review of literature
2005-06-16

Spontaneous pure acute subdural haematoma (ASDH) without intraparenchymal or subarachnoid haemorrhage caused by a ruptured cerebral aneurysm is extremely rare. To our knowledge, the present case is the first report of an internal carotid artery bifurcation aneurysm presenting as pure ASDH. Suitable diagnostic investigations and therapeutic strategies are discussed. Arterial origin of bleeding should be considered in all cases of non-traumatic ASDH and a vascular anomaly has to be excluded. The neurological status on admission dictates the appropriate timing and methodology of the neuroradiological investigations.
Induction of the von Hippel‐Lindau tumor suppressor gene by late hypoxia limits HIF‐1 expression
2005-06-16

Abstract Hypoxia–inducible factor (HIF) remains the central focus of oxygen sensing during hypoxia. HIF is a heterodimeric transcription factor consisting of an oxygen‐regulated alpha‐ and a constitutively expressed beta subunit. The von Hippel‐Lindau tumor suppressor (pVHL) is a component of the E3 ubiquitin ligase complex and targets HIF‐α to proteasomal degradation, but also is known to exert a significant control on HIF transactivation activity. However, the understanding of the full interaction between HIF and pVHL has been hindered by a lack in the understanding of pVHL regulation. Here, we report that pVHL itself is induced in prolonged hypoxia in a kinetic that parallels the observed downregulation of HIF‐1α protein under such conditions. In addition, we document direct HIF‐1α binding to the VHL promoter and identify a functional hypoxia response element (HRE) within the VHL promoter. Such induction of pVHL in hypoxia furthermore has functional implications for the HIF dependent hypoxic response, implicating a physiologically relevant feedback mechanism. These results provide an intriguing model, whereby HIF self‐regulates expression through VHL and highlight the role of pVHL as a unifying mechanism of HIF regulation. © 2005 Wiley‐Liss, Inc.
Genotype–phenotype relationships in hepatocellular tumors from mice and man†
2005-06-17

Experimentally induced liver tumors in mice harbor activating mutations in either Catnb (beta-catenin) or Ha-ras, according to the carcinogenic treatment. We have now investigated by microarray analysis the gene expression profiles in tumors of the two genotypes. In total, 364 genes or expressed sequences with aberrant expression relative to normal liver were identified, but only 30 of these demonstrated unidirectional changes in both tumor types. Several functional clusters were identified that involve changes in amino acid utilization and ammonia disposition in Catnb-mutated tumors as opposed to alterations in lipid and cholesterol metabolism in Ha-ras-mutated tumors. Moreover, several genes coding for inhibitory molecules within the Wnt-signaling pathway were upregulated in Catnb-mutated tumors, suggesting induction of a negative feedback loop, whereas Ha-ras-mutated tumors showed alterations in the expression of several genes functional in monomeric G-protein signaling. We conclude that mouse hepatoma cells adopt different evolutionary strategies that allow for their selective outgrowth under variable environmental conditions. Human hepatocellular cancers (HCC) lack RAS mutations but are frequently mutated in CTNNB1, the human Catnb ortholog. The set of genes aberrantly expressed in Catnb-mutated mouse tumors was used to screen, by expression profiling, for dysregulation of orthologous genes within a panel of 25 HCCs, of which 10 were CTNNB1-mutated. HCCs with activated beta-catenin displayed a gene expression profile that was similar to Catnb-mutated mouse tumors but distinct from the other human HCCs. In conclusion, expression fingerprints may be used for diagnostic purposes and potential new therapeutic intervention strategies. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index/html).
Aortic Dissection Mimicking Subarachnoidal Hemorrhage
2005-06-17

In this report we describe a comatose patient with proximal aortic dissection who presented with the signs of subarachnoidal hemorrhage. Shortly before losing consciousness, the patient complained of an excruciating headache. Upon initial examination, neck stiffness and opisthotonos were present. The cardiovascular examination, chest radiograph, and cerebral computed tomography were normal. Eight hours later, the aortic dissection was verified by a thoracic computed tomography. This case shows that aortic dissection, which causes severe pain and possibly transient malperfusion of the carotid arteries, may present with the misleading signs of subarachnoidal hemorrhage but without classical symptoms of aortic syndromes.