julilili42/papers huggingface dataset:
Sensing and Transduction in Semiconducting MOX Gas Sensors; Phenomenological and Spectroscopic Investigations
2007-10-01

The contribution describes the rationale of a research approach that is based on a combination of investigation techniques that provide complementary inputs on the surface chemistry and its electronic effect determined by the exposure of MOX to the surrounding atmosphere. Two examples are provided that demonstrate the value of the proposed strategy: First, the interaction between oxygen and water vapour at the surface of tin oxide is studied by a combination between conductance and IR measurements; Second, the origin of n-p conduction switch for iron oxide is examined by a combination between conductance and work function changes measurement.
New constraints on the mid-IR EBL from the HESS discovery of VHE γ-rays from 1ES 0229+200
2007-10-02

Aims.To investigate the very high energy (VHE: &gt;100 GeV) -ray emission from the high-frequency peaked BL Lac 1ES 0229+200.\\nMethods.Observations of 1ES 0229+200 at energies above 580 GeV were performed with the High Energy Stereoscopic System (HESS) in 2005 and 2006.\\nResults.1ES 0229+200 is discovered by HESS to be an emitter of VHE photons. A signal is detected at the 6.6 level in the HESS observations (41.8 h live time). The integral flux above 580 GeV is cm-2 s-1, corresponding to ~1.8% of the flux observed from the Crab Nebula. The data show no evidence for significant variability on any time scale. The observed spectrum is characterized by a hard power law ( ) from 500 GeV to ~15 TeV.\\nConclusions.The high-energy range and hardness of the observed spectrum, coupled with the object's relatively large redshift ( z = 0.1396), enable the strongest constraints so far on the density of the Extragalactic Background Light (EBL) in the mid-infrared band. Assuming that the emitted spectrum is not harder than , the HESS data support an EBL spectrum and density close to the lower limit from source counts measured by Spitzer, confirming the previous indications from the HEGRA data of 1ES 1426+428 (z=0.129). Irrespective of the EBL models used, the intrinsic spectrum of 1ES 0229+200 is hard, thus locating the high-energy peak of its spectral energy distribution above a few TeV.
Myogenesis in human denervated muscle biopsies
2007-10-02

Abstract Electron microscopic studies of long‐term denervated rat muscles have identified very small, immature myofibers that are believed to arise from detached satellite cells that have fused to form new fibers within the interstitial space. At present, it is unknown whether and to what extent equivalent fibers exist in denervated human muscle. Serial sections of muscle biopsies from 66 patients diagnosed with polyneuropathy or amyotrophic lateral sclerosis were immunolabeled with anti‐NCAM and anti‐neonatal myosin heavy chain monoclonal antibodies that are both neurally and developmentally regulated. We evaluated 200 myofibers in each section. Of the biopsy specimens, 75% contained small myofibers that showed a thin perinuclear cytoplasmic rim. Small fibers expressing neonatal myosin heavy chain (MHCn+) were found in all of these biopsies (100%) and NCAM+ fibers in 98%. The percentage of MHCn+ small fibers averaged 82% and NCAM+ small myofibers averaged 40%. The percentage of NCAM+ small fibers was significantly lower than that of MHCn+ fibers. In contrast, the percentage of MHCn+ vs. NCAM+ angular atrophic fibers did not show a significant difference. A substantial subset of neurogenic biopsies showed small fibers that differ from angular atrophic fibers both in size and expression pattern of MHCn and NCAM. Myogenesis appears to be a frequent finding in neurogenic atrophy. Muscle Nerve, 2007
A Peptide-gated Ion Channel from the Freshwater Polyp Hydra
2007-10-03

Chemical transmitters are either low molecular weight molecules or neuropeptides. As a general rule, neuropeptides activate only slow metabotropic receptors. To date, only one exception to this rule is known, the FMRFamide-activated Na(+) channel (FaNaC) from snails. Until now FaNaC has been regarded as a curiosity, and it was not known whether peptide-gated ionotropic receptors are also present in other animal groups. Nervous systems first evolved in cnidarians, which extensively use neuropeptides. Here we report cloning from the freshwater cnidarian Hydra of a novel ion channel (Hydra sodium channel, HyNaC) that is directly gated by the neuropeptides Hydra-RFamides I and II and is related to FaNaC. The cells expressing HyNaC localize to the base of the tentacles, adjacent to the neurons producing the Hydra-RFamides, suggesting that the peptides are the natural ligands for this channel. Our results suggest that neuropeptides were already used for fast transmission in ancient nervous systems.
A unique case of coincidence of early onset Parkinson's disease and multiple sclerosis
2007-10-03

Abstract We report on a patient who developed left arm rest/postural tremor at age 24 and responded well to trihexyphenidyl. One year later spastic paraparesis appeared, and multiple sclerosis was diagnosed on the basis of clinical, radiological, and laboratory evidence. Although paraparesis improved after immunosuppressant therapy, a complete picture of an asymmetric parkinsonian syndrome gradually developed. Excellent response to levodopa, drug‐induced dyskinesias, and DaTSCAN revealing pathology congruent with Parkinson's disease (PD) indicate a coincidental etiopathogenetic relationship of both clinical entities: multiple sclerosis and PD. Genetic analyses focusing on autosomal recessive parkinsonism (parkin, DJ1, and PINK1) were negative. To the best of our knowledge, only 15 cases of parkinsonism in association with multiple sclerosis have been reported, and their relationship has been interpreted to be either causal or coincidental. This is the first report of a coincidence of both entities, in which the parkinsonian syndrome developed first and before age 30. © 2007 Movement Disorder Society
Elloxazinones A and B, New Aminophenoxazinones from Streptomyces griseus Acta 2871
2007-10-04

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, please click on HTML or PDF.
Monitoring the Interactions of Tocopherol Homologues with Reversed-Phase Stationary HPLC Phases by 1H Suspended-State Saturation Transfer Difference High-Resolution/Magic Angle Spinning NMR Spectroscopy
2007-10-05

The separation process in reversed-phase high-performance liquid chromatography employing C18 phases is mainly due to hydrophobic interactions. The separation of tocopherol isomers, exhibited by the C30 phases, however, is additionally driven by shape selectivity. This phenomenon is investigated by suspended-state nuclear magnetic resonance spectroscopy using the saturation transfer difference technique, which was originally introduced to study protein-ligand interactions. The interaction strength between beta-/gamma-tocopherol and three different stationary phases was estimated qualitatively. The nuclear magnetic resonance data are compared to chromatographic data, and a similar mode of interaction between the analytes and the stationary phases is elucidated.
Malaria diagnosis under field conditions in the Venezuelan Amazon
2007-10-05

To improve practical, accurate diagnosis of malaria in the Amazon rainforest of Venezuela, two rapid diagnostic tests (RDT) (OptiMAL-IT) and FalciVax) and a laboratory light microscope, used in the field with a battery-operated head lamp as an external light source, were evaluated against the standard laboratory microscope procedure for malaria detection. One hundred and thirty-six Yanomami patients were studied for the presence of malaria parasites. Thirty-three patients (24%) were positive for malaria (Plasmodium falciparum, P. vivax, P. malariae). Twenty-one (64%) of the positive patients had <100 parasites/microl. Both RDTs showed poor sensitivity (24.2% for OptiMAL-IT) and 36.4% for FalciVax) but good specificity (99% both for OptiMAL-IT) and FalciVax). Field and laboratory microscopy showed sensitivities of 94% and 91%, respectively. The kappa coefficient was 0.90, indicating a high agreement between field and laboratory microscopy. We conclude that (i) adequate slide reading cannot be substituted by either of the two RDTs in the Venezuelan Amazon and (ii) the use of a light source such as that described above makes slide reading more feasible than hitherto in remote areas without electricity.
The grainyhead like 2 gene (GRHL2), alias TFCP2L3, is associated with age-related hearing impairment
2007-10-06

Age-related hearing impairment (ARHI) is the most prevalent sensory impairment in the elderly. ARHI is a complex disease caused by an interaction between environmental and genetic factors. The contribution of various environmental factors has been relatively extensively studied. In contrast, investigations to identify the genetic risk factors have only recently been initiated. In this paper we describe the results of an association study performed on 2418 ARHI samples derived from nine centers from seven European countries. In 70 candidate genes, a total of 768 tag single nucleotide polymorphisms (SNPs) were selected based on HAPMAP data. These genes were chosen among the monogenic hearing loss genes identified in mice and men in addition to several strong functional candidates. After genotyping and data polishing, statistical analysis of all samples combined resulted in a P-value that survived correction for multiple testing for one SNP in the GRHL2 gene. Other SNPs in this gene were also associated, albeit to a lesser degree. Subsequently, an analysis of the most significant GRHL2 SNP was performed separately for each center. The direction of the association was identical in all nine centers. Two centers showed significant associations and a third center showed a trend towards significance. Subsequent fine mapping of this locus demonstrated that the majority of the associated SNPs reside in intron 1. We hypothesize that the causative variant may change the expression levels of a GRHL2 isoform.
R91W mutation in Rpe65 leads to milder early-onset retinal dystrophy due to the generation of low levels of 11-cis-retinal
2007-10-06

RPE65 is a retinal pigment epithelial protein essential for the regeneration of 11-cis-retinal, the chromophore of cone and rod visual pigments. Mutations in RPE65 lead to a spectrum of retinal dystrophies ranging from Leber's congenital amaurosis to autosomal recessive retinitis pigmentosa. One of the most frequent missense mutations is an amino acid substitution at position 91 (R91W). Affected patients have useful cone vision in the first decade of life, but progressively lose sight during adolescence. We generated R91W knock-in mice to understand the mechanism of retinal degeneration caused by this aberrant Rpe65 variant. We found that in contrast to Rpe65 null mice, low but substantial levels of both RPE65 and 11-cis-retinal were present. Whereas rod function was impaired already in young animals, cone function was less affected. Rhodopsin metabolism and photoreceptor morphology were disturbed, leading to a progressive loss of photoreceptor cells and retinal function. Thus, the consequences of the R91W mutation are clearly distinguishable from an Rpe65 null mutation as evidenced by the production of 11-cis-retinal and rhodopsin as well as by less severe morphological and functional disturbances at early age. Taken together, the pathology in R91W knock-in mice mimics many aspects of the corresponding human blinding disease. Therefore, this mouse mutant provides a valuable animal model to test therapeutic concepts for patients affected by RPE65 missense mutations.
Delta‐like 1 participates in the specification of ventral midbrain progenitor derived dopaminergic neurons
2007-10-08

Abstract Delta‐like 1 (Dlk1), a member of the Delta/Notch protein family, is expressed in the mouse ventral midbrain (VM) as early as embryonic day 11.5 (E11.5) followed by exclusive expression in tyrosine 3‐monooxygenase (TH) positive neurons from E12.5 onwards. To further elucidate the yet unknown function of Dlk1 in VM neuron development, we investigated the effect of soluble Dlk1 protein as well as the intrinsic Dlk1 function in the course of VM progenitor expansion and dopaminergic (DA) neuron differentiation in vitro . Dlk1 treatment during expansion increased DA progenitor proliferation and the proportion of NR4A2+ neurons expressing TH after differentiation, whereas Dlk1 treatment during the course of DA precursor differentiation did not alter TH+ neuron counts. In contrast, silencing of endogenously expressed Dlk1 prior to DA precursor differentiation partially prevented the expression of DA neuron markers, which was not accompanied with alteration of overall or local proliferation. Due to the latter finding in combination with the absence of Dlk1 negative DA neurons in differentiated cultures, we suggest that Dlk1 expression might have a permissive effect on DA neuron differentiation in vitro . The study presented here is the first publication identifying Dlk1 effects on ventral midbrain‐derived DA precursor differentiation.
HESS very-high-energy gamma-ray sources without identified counterparts
2007-10-09

Context. The detection of gamma rays in the very-high-energy (VHE) energy range (100 GeV-100 TeV) provides a direct view of the parent population of ultra-relativistic particles found in astrophysical sources. For this reason, VHE gamma rays are useful for understanding the underlying astrophysical processes in non-thermal sources. Aims. We investigate unidentified VHE gamma-ray sources that have been discovered with HESS in the most sensitive blind survey of the Galactic plane at VHE energies conducted so far. Methods. The HESS array of imaging atmospheric Cherenkov telescopes (IACTs) has a high sensitivity compared with previous instruments (∼0.01 Crab in 25 h observation time for a 5σ point-source detection), and with its large field of view, is well suited for scan-based observations. The on-going HESS survey of the inner Galaxy has revealed a large number of new VHE sources, and for each we attempt to associate the VHE emission with multi-wavelength data in the radio through X-ray wavebands. Results. For each of the eight unidentified VHE sources considered here, we present the energy spectra and. sky maps of the sources and their environment. The VHE morphology is compared with available multi-wavelength data (mainly radio and X-rays). No plausible counterparts are found. © ESO 2007.
The “pseudo‐craniovertebral articulation” in the deep‐sea fish Stomias boa (Teleostei: Stomiidae)
2007-10-09

Abstract Many predatory deep‐sea fishes show highly specialized modifications of their feeding apparatus, e.g., elongate jaws studded with long daggerlike teeth, often combined with a very distensible stomach, to be capable of swallowing relatively large prey. These striking features can be observed in members of the marine teleost family Stomiidae. The present study gives a detailed morphological description of the mesopelagic predatory fish, Stomias boa, based on a combined approach of clearing and double staining, serial sections and dissection. In this genus, large pads made of dense connective tissue extend from the first enlarged neural arch to the ventral side of the chordal sheath, embracing the prominent exoccipitals and thus constituting a kind of double ball‐ and socket joint for the head. The notochordal occipito‐vertebral gap is enlarged, probably not by loss of vertebral centra as is proposed for other genera of the stomiid family, e.g., in Astronesthes or Photostomias . We conclude that this “pseudo‐craniovertebral articulation” serves as a functional substitute for the absent vertebrae and strengthens the flexible, anterior part of the vertebral column during extreme dorsal expansion of the gape during prey capture and swallowing. J. Morphol., 2008. © 2007 Wiley‐Liss, Inc.
AvianClockgene polymorphism: evidence for a latitudinal cline in allele frequencies
2007-10-10

Abstract In comparison with most animal behaviours, circadian rhythms have a well‐characterized molecular genetic basis. Detailed studies of circadian clock genes in ‘model’ organisms provide a foundation for interpreting the functional and evolutionary significance of polymorphic circadian clock genes found within free‐living animal populations. Here, we describe allelic variation in a region of the avian Clock orthologue which encodes a functionally significant polyglutamine repeat ( Clk polyQcds), within free‐living populations of two passerine birds, the migratory bluethroat ( Luscinia svecica ) and the predominantly nonmigratory blue tit ( Cyanistes caeruleus ). Multiple Clk polyQcds alleles were found within populations of both species (bluethroat: 12 populations, 7 alleles; blue tit: 14 populations, 9 alleles). Some populations of both species were differentiated at the Clk polyQcds locus as measured by F ST and R ST values. Among the blue tit, but not bluethroat populations, we found evidence of latitudinal clines in (i) mean Clk polyQcds repeat length, and (ii) the proportions of three Clk polyQcds genotype groupings. Parallel analyses of microsatellite allele frequencies, which are considered to reflect selectively neutral processes, indicate that interpopulation allele frequency variation at the Clk polyQcds and microsatellite loci does not reflect the same underlying demographic processes. The possibility that the observed interpopulation Clk polyQcds allele frequency variation is, at least in part, maintained by selection for microevolutionary adaptation to photoperiodic parameters correlated with latitude warrants further study.
Rangewide phylogeography in the greater horseshoe bat inferred from microsatellites: implications for population history, taxonomy and conservation
2007-10-10

Abstract The distribution of genetic variability across a species’ range can provide valuable insights into colonization history. To assess the relative importance of European and Asian refugia in shaping current levels of genetic variation in the greater horseshoe bats, we applied a microsatellite‐based approach to data collected from 56 localities ranging from the UK to Japan. A decline in allelic richness from west Asia to the UK and analyses of F ST both imply a northwestward colonization across Europe. However, sharp discontinuities in gene frequencies within Europe and between the Balkans and west Asia (Syria/Russia) are consistent with suture zones following expansion from multiple refugia, and a lack of recent gene flow from Asia Minor. Together, these results suggest European populations originated from west Asia in the ancient past, and experienced a more recent range expansion since the Last Glacial Maximum. Current populations in central Europe appear to originate from the Balkans and those from west Europe from either Iberia and/or Italy. Comparisons of R ST and F ST suggest that stepwise mutation has contributed to differentiation between island and continental populations (France/UK and China/Japan) and also among distant samples. However, pairwise R ST values between distant populations appear to be unreliable, probably due to size homoplasy. Our findings also highlight two priorities for conservation. First, stronger genetic subdivision within the UK than across 4000 km of continental Eurasia is most likely the result of population fragmentation and highlights the need to maintain gene flow in this species. Second, deep splits within China and between Europe and China are indicative of cryptic taxonomic divisions which need further investigation.
Autoantibodies in patients with Down Syndrome: Early senescence of the immune system or precocious markers for immunological diseases?
2007-10-10

Aims: Down syndrome (DS) patients present several immunological disturbances, with high rates of infections, malignancies and autoimmune phenomena. The present study aims to evaluate the prevalence of autoantibodies in children and adolescents with DS that are not usually investigated, and to establish possible clinical and laboratory associations. Methods: One hundred and fifty Caucasoid DS patients from southern Brazil (93M, 57F; median age 4 years) and 105 healthy children (58M, 47F; median age 8 years) were evaluated for the presence of anti‐mitochondrial (AMA), smooth‐muscle (SMA), liver‐kidney microsomal (LKM), nuclear (ANA), gastric parietal cell (GPC) and neutrophil cytoplasmic (ANCA) antibodies, by indirect immunofluorescence, and rheumatoid factor (RF), by turbidimetry. Results: Forty‐three DS patients (28.6%) showed positivity to at least one autoantibody, in comparison with eight of the controls (7.6%; P &lt; 0.001). RF was detected in 28% of the patients and 6.7% of the controls ( P &lt; 0.001). ANCA, SMA and ANA were positive in 0.66% of the patients, while AMA, GPC and LKM were negative in all the samples. Currently, none of the RF positive patients has clinical evidence of rheumatic disease. Conclusions: Data from the present study suggest that the high incidence of positive RF observed in DS patients might be related to the senescence of the immune system or could be an earlier marker of rheumatic diseases in these patients.
Total Synthesis of Cruentaren A.
2007-10-10

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, please click on HTML or PDF.
Abstract 1901: Dual-source Ct In Non-invasive Coronary Artery Angiography: Effect Of Heart Rate, Heart Rate Variability And Calcification On Image Quality And Diagnostic Accuracy In An Unselected Patient Population
2007-10-16

Objective: The aim of this study was to assess DSCT for evaluation of coronary artery disease in an unselected patient population. Impact of heart rate, heart rate variability and calcification on image quality and diagnostic accuracy were, thereby, considered. Subjects and Methods: 100 consecutive patients with known or suspected CAD underwent DSCT and invasive coronary angiography. Image quality (IQ) was assessed using a 4-point scale (1: excellent; 4: non-diagnostic). Accuracy of DSCT in detection or exclusion of significant stenosis (&gt;50%) was evaluated on a per-segment and per-patient level. Effects of heart rate, heart rate variability and calcification on IQ and accuracy were analyzed by multivariate regression and between subgroups of predictor variables. Simple regression was performed to calculate thresholds for adequate IQ. Results: Average heart rate was 64.9± 13.2 bpm, mean variability 23.6± 36.2 beats per CT-examination and mean Agatston score 786.5± 965.9. Diagnostic image quality was obtained in 90.2% of segments. Sensitivity, specificity, positive and negative predictive values for the presence of significant stenosis was: by segment 91.1%, 92.0%, 75.4% and 97.5%; by patient 100%, 81.5%, 93.6% and 100%. According to multivariate regression, IQ was significantly related to heart rate variability and calcification (P=0.025; P&lt;0.0001); number of non-diagnostic segments was significantly affected by calcification only. Also, in a multivariate regression, calcification was the single factor with significant impact on diagnostic accuracy (P=0.0003). Conclusion: Whilst DSCT achieves heart rate independent image quality, the latter remains prone to heart rate variability and calcification. In an unselected patient collective, calcium burden proves to be the single determinant of diagnostic accuracy.