julilili42/papers huggingface dataset:
Discovery of very-high-energy γ-ray emission from the vicinity of PSR J1913+1011 with HESS
2008-03-04

The HESS experiment, an array of four Imaging Atmospheric Cherenkov Telescopes with high sensitivity and large field-of-view, has been used to search for emitters of very-high-energy (VHE, &gt;100 GeV) -rays along the Galactic plane, covering the region 30° 60°, 280° 330°, and -3° 3°. In this continuation of the HESS Galactic Plane Scan, a new extended VHE -ray source was discovered at =19 12 49 , =+10°09 ́06 ́ ́(HESS J1912+101). Its integral flux between 1-10 TeV is ~10% of the Crab Nebula flux in the same energy range. The measured energy spectrum can be described by a power law d with a photon index . HESS J1912+101 is plausibly associated with the high spin-down luminosity pulsar PSR J1913+1011. We also discuss associations with an as yet unconfirmed SNR candidate proposed from low frequency radio observation and/or with molecular clouds found in 13CO data.
Coherent single atom shuttle between two Bose-Einstein condensates
2008-03-04

We study an atomic quantum dot representing a single hyperfine "impurity" atom which is coherently coupled to two well-separated Bose-Einstein condensates, in the limit when the coupling between the dot and the condensates dominates the inter-condensate tunneling coupling. It is demonstrated that the quantum dot by itself can induce large-amplitude Josephson-like oscillations of the particle imbalance between the condensates, which display a two-frequency behavior. For noninteracting condensates, we provide an approximate solution to the coupled nonlinear equations of motion which allows us to obtain these two frequencies analytically.
Neurocognitive effects of atypical and conventional antipsychotic drugs in schizophrenia: A naturalistic 6-month follow-up study
2008-03-04

The present study aimed to assess the neurocognitive effects of atypical and conventional antipsychotic drugs on neurocognition under naturalistic treatment conditions. Eighty-two patients with schizophrenia underwent a comprehensive neuropsychological assessment both at baseline during inpatient treatment and 6 months after discharge from hospital (follow-up). From this sample, we selected two subgroups of patients, which had either a continuous atypical (n=33) or conventional (n=16) antipsychotic medication. Twenty-seven out of 40 healthy controls were also retested to control for practice effects. Both patient groups showed a moderate and significant improvement in global cognitive functioning. The repeated measurement ANOVAs revealed no differential treatment effects for all neuropsychological domains. These results remained after controlling for potential confounders between groups. Administering antipsychotic medications in an individually optimized manner seems to have the potential to improve some aspects of neurocognition in schizophrenia, regardless of the kind of antipsychotic medication.
Synthese und Untersuchung von kohlenstoff‐ und stickstoffzentrierten (Z) trigonal‐prismatischen Wolframclustern des Formeltyps A[W6ZCl18]
2008-03-04

Abstract Synthesis and Characterization of Carbon‐ and Nitrogen‐Centered (Z) Trigonal Prismatic Tungsten Clusters of the Formula Type A[W 6 ZCl 18 ] Solid state reactions of tungsten(IV) chloride and carbodiimides (cyanamides) of lithium, sodium, calcium and silver yielded black crystalline powders of centered (Z) trigonal‐prismatic tungsten cluster compounds having the general formula A[W 6 ZCl 18 ] with A = Li, Na, Ca, Ag and Z = C, N. Crystal structures of the corresponding compounds were investigated by powder and single‐crystal X‐ray diffraction. The nature of the central atom was studied by mass spectrometry and nuclear magnetic resonance spectrometry. It turned out that the central atom can be C (in the case of the lithium and sodium compound) or N (in the case of the sodium and calcium compound).
Differential Expression of Genes Important to Efferent Ductules Ion Homeostasis across Postnatal Development in Estrogen Receptor-慣 Knockout and Wildtype Mice
2008-03-04

Our earlier studies showed that estrogen was involved in the regulation of fluid reabsorption in adult mouse efferent ductules (ED), through estrogen receptor (ER) α and ERβ, by modulating gene expression of epithelial genes involved in ion homeostasis.However, little is known about the importance of ERα in the ED during postnatal development.Based on previous findings, we hypothesized that there should be a difference in the expression of epithelial ion transporters and anion producers in the ED of postnatal wild type (WT) and estrogen receptor α knockout (αERKO) mice.Using absolute, comparative and semi-quantitative RT-PCR along with immunohistochemistry, we looked at expression levels of several genes in the ED across postnatal development.The presence of estrogen in the testicular fluid was indirectly ascertained by immunohistochemical detection of the P450 aromatase in the testis.There was no immunohistochemically detectable difference in the expression of P450 aromatase in the testes and ERβ in the ED of WT and αERKO mice.ERα was only detected in the ED of WT mice.The absence of ERα in the ED of postnatally developing mice resulted in differential expression of mRNAs and/or proteins for carbonic anhydrase II, Na + /H + exchanger 3, down-regulated in adenoma, cystic fibrosis transmembrane regulator, and Na + /K + ATPase α1.Our data indicate that the absence of ERα resulted in altered expression of an epithelial ion producer and transporters during postnatal development of mice.We conclude that the presence of ERα is important for regulation of the ED function during the prepubertal developmental and postpubertal period.
Simultaneous in vivo positron emission tomography and magnetic resonance imaging
2008-03-05

Positron emission tomography (PET) and magnetic resonance imaging (MRI) are widely used in vivo imaging technologies with both clinical and biomedical research applications. The strengths of MRI include high-resolution, high-contrast morphologic imaging of soft tissues; the ability to image physiologic parameters such as diffusion and changes in oxygenation level resulting from neuronal stimulation; and the measurement of metabolites using chemical shift imaging. PET images the distribution of biologically targeted radiotracers with high sensitivity, but images generally lack anatomic context and are of lower spatial resolution. Integration of these technologies permits the acquisition of temporally correlated data showing the distribution of PET radiotracers and MRI contrast agents or MR-detectable metabolites, with registration to the underlying anatomy. An MRI-compatible PET scanner has been built for biomedical research applications that allows data from both modalities to be acquired simultaneously. Experiments demonstrate no effect of the MRI system on the spatial resolution of the PET system and &lt;10% reduction in the fraction of radioactive decay events detected by the PET scanner inside the MRI. The signal-to-noise ratio and uniformity of the MR images, with the exception of one particular pulse sequence, were little affected by the presence of the PET scanner. In vivo simultaneous PET and MRI studies were performed in mice. Proof-of-principle in vivo MR spectroscopy and functional MRI experiments were also demonstrated with the combined scanner.
REEP1 mutation spectrum and genotype/phenotype correlation in hereditary spastic paraplegia type 31
2008-03-05

Mutations in the receptor expression enhancing protein 1 (REEP1) have recently been reported to cause autosomal dominant hereditary spastic paraplegia (HSP) type SPG31. In a large collaborative effort, we screened a sample of 535 unrelated HSP patients for REEP1 mutations and copy number variations. We identified 13 novel and 2 known REEP1 mutations in 16 familial and sporadic patients by direct sequencing analysis. Twelve out of 16 mutations were small insertions, deletions or splice site mutations. These changes would result in shifts of the open-reading-frame followed by premature termination of translation and haploinsufficiency. Interestingly, we identified two disease associated variations in the 3'-UTR of REEP1 that fell into highly conserved micro RNA binding sites. Copy number variation analysis in a subset of 133 HSP index patients revealed a large duplication of REEP1 that involved exons 2-7 in an Irish family. Clinically most SPG31 patients present with a pure spastic paraplegia; rare complicating features were restricted to symptoms or signs of peripheral nerve involvement. Interestingly, the distribution of age at onset suggested a bimodal pattern with the appearance of initial symptoms of disease either before the age of 20 years or after the age of 30 years. The overall mutation rate in our clinically heterogeneous sample was 3.0%; however, in the sub-sample of pure HSP REEP1 mutations accounted for 8.2% of all patients. These results firmly establish REEP1 as a relatively frequent autosomal dominant HSP gene for which genetic testing is warranted. We also establish haploinsufficiency as the main molecular genetic mechanism in SPG31, which should initiate and guide functional studies on REEP1 with a focus on loss-of-function mechanisms. Our results should be valid as a reference for mutation frequency, spectrum of REEP1 mutations, and clinical phenotypes associated with SPG31.
Neurodegeneration and Motor Dysfunction in a Conditional Model of Parkinson's Disease
2008-03-05

α-Synuclein (α-syn) has been implicated in the pathogenesis of many neurodegenerative disorders, including Parkinson's disease. These disorders are characterized by various neurological and psychiatric symptoms based on progressive neuropathological alterations. Whether the neurodegenerative process might be halted or even reversed is presently unknown. Therefore, conditional mouse models are powerful tools to analyze the relationship between transgene expression and progression of the disease. To explore whether α-syn solely originates and further incites these alterations, we generated conditional mouse models by using the tet-regulatable system. Mice expressing high levels of human wild-type α-syn in midbrain and forebrain regions developed nigral and hippocampal neuropathology, including reduced neurogenesis and neurodegeneration in absence of fibrillary inclusions, leading to cognitive impairment and progressive motor decline. Turning off transgene expression in symptomatic mice halted progression but did not reverse the symptoms. Thus, our data suggest that approaches targeting α-syn-induced pathological pathways might be of benefit rather in early disease stages. Furthermore, α-syn-associated cytotoxicity is independent of filamentous inclusion body formation in our conditional mouse model.
Ammonia Triggers Photodamage of Photosystem II in the Cyanobacterium Synechocystis sp. Strain PCC 6803
2008-03-05

Ammonia has long been known to be toxic for many photosynthetic organisms; however, the target for its toxicity remains elusive. Here, we show that in the cyanobacterium Synechocystis sp. strain PCC 6803, ammonia triggers a rapid photodamage of photosystem II (PSII). Whereas wild-type cells can cope with this damage by turning on the FtsH2-dependent PSII repair cycle, the FtsH2-deficient mutant is highly sensitive and loses PSII activity at millimolar concentration of ammonia. Ammonia-triggered PSII destruction is light dependent and occurs already at low photon fluence rates. Experiments with monochromatic light showed that ammonia-promoted PSII photoinhibition is executed by wavebands known to directly destroy the manganese cluster in the PSII oxygen-evolving complex, suggesting that the oxygen-evolving complex may be a direct target for ammonia toxicity.
Archean inheritances in the pyroxene–amphibole-bearing gneiss of the Méiganga area (Central North Cameroon): Geochemical and 207Pb/206Pb age imprints
2008-03-05

The Méiganga area is located in the central part of the Panafrican belt of Cameroon. This region is underlain by a granitic and gneissic basement, crosscut, and covered by basaltic and phonolitic rocks. To the southwest of Méiganga, the pyroxene-and-amphibole-bearing gneiss shows the geochemical characteristics of Archean TTG (tonalite—trondhjemite—granodiorite) associations. The studied samples show LREE enrichment relative to the HREE (La N /Yb N = 7–28). This pattern of the REE, particularly the concentration of Y and Yb allowed us to consider some samples as derived from an Archean crust. Cathodoluminescence pictures of zircon crystals from the gneiss reveal magmatic oscillatory zoning with inherited cores. Age determinations employing the 207 Pb/ 206 Pb single-zircon evaporation method yielded Late Archean (∼2.6 Ga) to Palaeoproterozoic (∼1.7 Ga) ages. Ages around 2.0 Ga are interpreted to be close to the crystallization age, while the older ages might represent mixing ages, i.e., mixtures between a Palaeoproterozoic magmatic domain and an inherited Archean core. This study discusses the imprints of Archean crust inheritances on the pyroxene–amphibole-bearing gneisses of the Méiganga area.
Diurnality and nocturnality in nonhuman primates: comparative chronobiological studies in laboratory and nature
2008-03-05

Looking for differences in circadian clock characteristics of diurnal and nocturnal nonhuman primates, this article summarizes results of chronobiological studies carried out in various nocturnal, diurnal, and cathemeral prosimian and anthropoid primate species under controlled laboratory conditions, under seminatural conditions, and in the wild. In almost all circadian parameters investigated, no differences were discernible between the two main chrono-ecotypes, either in circadian period length and the influence upon it of after-effects, of light intensity, and ambient temperature, or in the PRC, re-entrainment behavior, rhythm splitting, and internal desynchronization. Diurnal and nocturnal or cathemeral species differed only in the phase of artificial or natural LDs to which their circadian activity phase was adjusted as well as in the characteristics of masking activity upon the rhythms produced by the direct inhibiting or enhancing effects of light. Pronounced lunar periodicity—observed in the activity rhythm of nocturnal neotropical owl monkeys, genus Aotus, in seminatural and natural environments as well as in wild cathemeral Malagasy lemurs, genus Eulemur—is shown to result from masking effects of moonlight. In captive Eulemur fulvus albifrons, a change from dark-active over cathemeral to light-active behavior, without concurrently changing the circadian phase-setting of activity to D, was produced by direct masking effects of a stepwise reduction of darktime luminosity on an LD 12:12 cycle. Long-term activity recordings carried out in wild diurnal Malagasy sifakas (Propithecus verreauxi) and cathemeral redfronted lemurs (Eulemur fulvus rufus), as well as in wild nocturnal owl monkeys (Aotus a. azarai) of the North Argentinean Chaco, yielded in all species distinct bimodal long- and short-day activity patterns with pronounced peaks during dusk and dawn. Applying Pittendrigh's two-oscillator concept to these results, it is hypothesized that the differences in chrono-ecotype behavior may result from variations in internal coupling and external phase-setting of morning and evening oscillators (m, e) to dawn and dusk, interacting with direct masking effects of light.
ChemInform Abstract: Synthesis of 8‐Substituted 12‐Methyl‐12H‐imidazo[4′,5′:2,3][1,4]diazepino[6,7,1‐jk]carbazoles.
2008-03-05

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.
Mapping translocation breakpoints by next-generation sequencing
2008-03-07

Balanced chromosome rearrangements (BCRs) can cause genetic diseases by disrupting or inactivating specific genes, and the characterization of breakpoints in disease-associated BCRs has been instrumental in the molecular elucidation of a wide variety of genetic disorders. However, mapping chromosome breakpoints using traditional methods, such as in situ hybridization with fluorescent dye-labeled bacterial artificial chromosome clones (BAC-FISH), is rather laborious and time-consuming. In addition, the resolution of BAC-FISH is often insufficient to unequivocally identify the disrupted gene. To overcome these limitations, we have performed shotgun sequencing of flow-sorted derivative chromosomes using “next-generation” (Illumina/Solexa) multiplex sequencing-by-synthesis technology. As shown here for three different disease-associated BCRs, the coverage attained by this platform is sufficient to bridge the breakpoints by PCR amplification, and this procedure allows the determination of their exact nucleotide positions within a few weeks. Its implementation will greatly facilitate large-scale breakpoint mapping and gene finding in patients with disease-associated balanced translocations.
The regulation of SIRT2 function by cyclin-dependent kinases affects cell motility
2008-03-10

Cyclin-dependent kinases (Cdks) fulfill key functions in many cellular processes, including cell cycle progression and cytoskeletal dynamics. A limited number of Cdk substrates have been identified with few demonstrated to be regulated by Cdk-dependent phosphorylation. We identify on protein expression arrays novel cyclin E–Cdk2 substrates, including SIRT2, a member of the Sirtuin family of NAD+-dependent deacetylases that targets α-tubulin. We define Ser-331 as the site phosphorylated by cyclin E–Cdk2, cyclin A–Cdk2, and p35–Cdk5 both in vitro and in cells. Importantly, phosphorylation at Ser-331 inhibits the catalytic activity of SIRT2. Gain- and loss-of-function studies demonstrate that SIRT2 interfered with cell adhesion and cell migration. In postmitotic hippocampal neurons, neurite outgrowth and growth cone collapse are inhibited by SIRT2. The effects provoked by SIRT2, but not those of a nonphosphorylatable mutant, are antagonized by Cdk-dependent phosphorylation. Collectively, our findings identify a posttranslational mechanism that controls SIRT2 function, and they provide evidence for a novel regulatory circuitry involving Cdks, SIRT2, and microtubules.
Effects of different forms of nitrogen fertilizers on arsenic uptake by rice plants
2008-03-10

Abstract A pot microcosm experiment was conducted to investigate the effect of different forms of N fertilizers on As uptake by rice. Compared to a nontreated control, addition of nitrate reduced Fe(II) concentration in soil solution, while treatment with ammonium enhanced Fe(III) reduction, probably coupled to NH+4 oxidation in the nonrhizosphere. Most-probable-number (MPN) enumerations revealed high densities of nitrate-dependent Fe(II)-oxidizing microorganisms. The addition of nitrate decreased Fe plaque formation on the root surface, accompanied by much lower dissolved Fe(II) concentrations in the rhizosphere soil solution compared to the nonamended control. Nitrate addition also reduced As uptake by the rice plant. These results suggest that nitrate may inhibit Fe(III) reduction and/or stimulate nitrate-dependent Fe(II) oxidation, leading to As coprecipitation with, or adsorption to, Fe(III) minerals in the soil. Although Fe plaque formation on the root surface is reduced, nitrate-dependent stimulation of Fe(II) oxidation and/or inhibition of Fe(III) reduction in the bulk soil sequesters mobile As in the soil, resulting in reduced As uptake by rice.
Verification of temporal properties in automotive embedded software
2008-03-10

The amount of software in embedded systems has increased significantly over the last years and, therefore, the verification of embedded software is of fundamental importance. One of the main problems in embedded software is to verify variables and functions based on temporal properties. Formal property verification using model checker often suffers from the state space explosion problem when a large software design is considered. In this paper, we propose two new approaches to integrate assertions in the verification of embedded software using simulation-based verification. Firstly, we extended a SystemC hardware temporal checker with interfaces in order to monitor the embedded software variables and functions that are stored in a microprocessor memory model. Secondly, we derived a SystemC model from the original C program in order to integrate directly with the SystemC temporal checker. We performed a case study on an embedded software from automotive industry which is responsible for controlling read and write requests to a non-volatile memory.
Pleistocene neotectonics and Fe-mineralizations in the Ahnet-Mouydir area (northern margin of the Hoggar Massif, Algerian Sahara)
2008-03-10

Strongly mineralized lithologies were found in 4 different depositional settings along the northern margin of the Hoggar Massif in southern Algeria: (1) Pleistocene fluvial terraces, (2) pebble-filled erosional furrows in marine Silurian and Upper Devonian shales, (3) sedimentary dykes in Givetian mud buildups and (4) tectonic faultfissures and cracks in Upper Devonian shales. In spite of the contrasting sedimentary environment, all these rocks display very similar properties and are considered as contemporaneous. They are characterized by high porosities, intense Fe-mineralization and a great variety of accompanying, secondary minerals formed in a subrecent continental regime under pluvial to arid conditions. The dykes, faults and cracks are direct evidence of tensional stress during the early and middle Pleistocene which has not been observed so far. The complex sedimentary and diagenetic history of conglomerates, breccias, sandstones, ferricretes, calcretes and claystones in these settings was analyzed using SEM, EDX-microprobe, XRD, transmitted and reflected light petrography and is documented in hitherto unknown details.
Fetuin-A Induces Cytokine Expression and Suppresses Adiponectin Production
2008-03-12

We provide novel evidence that the secreted liver protein fetuin-A induces low-grade inflammation and represses adiponectin production in animals and in humans. These data suggest an important role of fatty liver in the pathophysiology of insulin resistance and atherosclerosis.
3-(2-Fluorophenyl)-6-(phenoxymethyl)-1,2,4-triazolo[3,4-b][1,3,4]thiadiazole
2008-03-12

The crystal structure of the title compound, C(16)H(11)FN(4)OS, was synthesized in the course of our studies on 1,2,4-triazolo[3,4-b][1,3,4]thia-diazo-les as inhibitors of p38 mitogen-activated protein kinase (MAPK). The three-dimensional data obtained were used to generate a three-dimensional pharmacophore model for in silico database screening. The dihedral angles between the central heterocylic system and the fluoro-phenyl and phenyl rings are 20.21 (3) and 5.43 (1)°, respectively; the dihedral angle between the two benzene rings is 15.80 (4)°.
6-Amino-1-benzyl-4-(4-chlorophenyl)-3-(4-pyridyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile
2008-03-12

The crystal structure of the title compound, C(25)H(18)ClN(5)O, was determined in the course of our studies on the synthesis of 1,4-dihydro-pyrano[2,3-c]pyrazole as an inhibitor of the p38 mitogen-activated protein kinase (MAPK). The compound was prepared via a base-catalysed synthesis from 1-benzyl-3-(4-pyrid-yl)-1H-pyrazol-5(4H)-one with p-chloro-aldehyde and malononitrile. The crystal data obtained were used to generate a three-dimensional pharmacophore model for in silico database screening. The phenyl ring is disordered over two positions, with site occupancy factors of 0.55 and 0.45. The dihedral angles between the 1,4-dihydropyrano[2,3-c]pyrazole unit and the chloro-phenyl and pyridine rings are 83.7 (1) and 16.0 (1)°, respectively. The chloro-phenyl and pyridine rings make a dihedral angle of 86.8 (2)°.