julilili42/papers huggingface dataset:
FAIR‐TrueFISP imaging of cerebral perfusion in areas of high magnetic susceptibility differences at 1.5 and 3 Tesla
2007-04-04

Abstract Purpose To estimate cerebral blood perfusion in areas of strong magnetic susceptibility changes with high spatial and temporal resolution using a flow‐sensitive alternating inversion recovery (FAIR) arterial spin labeling (ASL) method. Materials and Methods We implemented an ASL method that is capable of imaging perfusion in areas of high magnetic susceptibility changes by combining a FAIR spin preparation with a true fast imaging in steady precession (TrueFISP) data acquisition strategy. A TrueFISP readout sequence was applied especially in regions with magnetic field inhomogeneities and compared with corresponding FAIR measurements obtained with a standard echo‐planar imaging (EPI) readout. Quantitative perfusion images were obtained at 1.5 Tesla (1.5T) from eight healthy volunteers (24–42 years old) and one patient (23 years old). FAIR‐TrueFISP perfusion images were compared with FAIR echo‐planar images. T1 maps, which are necessary for quantitative perfusion estimation, were obtained with inversion recovery (IR) TrueFISP and IR EPI. Additionally, high‐resolution perfusion measurements were performed on four volunteers at 3T. Results The two ASL perfusion imaging modalities yielded comparable diagnostic image quality in brain areas with low susceptibility differences at 1.5T. Cerebral perfusion of gray matter (GM) areas was 105.7 ± 5.2 mL/100 g/minute for FAIR‐TrueFISP and 88.8 ± 14.6 mL/100 g/minute for FAIR‐EPI at 1.5T, and 70.4 ± 7.1 mL/100 g/minute for FAIR‐TrueFISP and 63.5 ± 6.9 mL/100 g/minute for FAIR‐EPI at 3.0T. Higher perfusion values at 1.5T were due to more pronounced partial‐volume effects from fast moving spins at lower spatial resolution. The FAIR‐TrueFISP sequence showed no significant distortions and markedly reduced signal void artifacts in areas of high susceptibility changes (e.g., near brain–bone transitions and close to metallic clips) compared to FAIR‐EPI. At 3T, highly resolved FAIR‐TrueFISP perfusion images were acquired with an in‐plane resolution of up to 1.3 mm. Conclusion FAIR‐TrueFISP allows for assessment of cerebral perfusion in areas of critically high susceptibility changes with conventional ASL methods. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Sebacinales are common mycorrhizal associates of Ericaceae
2007-04-05

Previous reports of sequences of Sebacinales (basal Hymenomycetes) from ericoid mycorrhizas raised the question as to whether Sebacinales are common mycorrhizal associates of Ericaceae, which are usually considered to associate with ascomycetes. Here, we sampled 239 mycorrhizas from 36 ericoid mycorrhizal species across the world (Vaccinioideae and Ericoideae) and 361 mycorrhizas from four species of basal Ericaceae lineages (Arbutoideae and Monotropoideae) that do not form ericoid mycorrhizas, but ectendomycorrhizas. Sebacinales were detected using sebacinoid-specific primers for nuclear 28S ribosomal DNA, and some samples were investigated by transmission electron microscopy (TEM). Diverging Sebacinales sequences were recovered from 76 ericoid mycorrhizas, all belonging to Sebacinales clade B. Indeed, some intracellular hyphal coils had ultrastructural TEM features expected for Sebacinales, and occurred in living cells. Sebacinales belonging to clade A were found on 13 investigated roots of the basal Ericaceae, and TEM revealed typical ectendomycorrhizal structures. Basal Ericaceae lineages thus form ectendomycorrhizas with clade A Sebacinales, a clade that also harbours ectomycorrhizal fungi. This further supports the proposition that Ericaceae ectendomycorrhizas involve ectomycorrhizal fungal taxa. When ericoid mycorrhizas evolved secondarily in Ericaceae, a shift of mycobionts occurred to ascomycetes and clade B Sebacinales, hitherto not described as ericoid mycorrhizal fungi.
Development and characterization of novel microsatellite markers for the common earthworm (Lumbricus terrestris L.)
2007-04-05

Abstract We developed and characterized 10 highly polymorphic microsatellite loci from an SSR‐enriched genomic DNA library of the common earthworm ( Lumbricus terrestris L). Characterization of these loci using 32 individuals revealed high levels of genetic diversity, five to 18 alleles per locus and a high observed and expected heterozygosity. These loci will be used for paternity analysis and population genetic studies of the co‐evolution between L. terrestris and its parasites.
Perceived self-competence and relationship experiences in inpatient psychotherapy - a pilot study.
2007-04-05

A model of mutual interactions is proposed for the variables under investigation. RESULTS suggest that the positive association between the therapeutic relationship and symptom reduction could partly be explained by an improvement in perceived self-competence.
Synthesis of Benzomorphan Analogues by Intramolecular Buchwald—Hartwig Cyclization.
2007-04-05

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, please click on HTML or PDF.
A two-dimensional approach to the study of motivation in lexical typology and its first application to French high-frequency vocabulary
2007-04-06

‘Morphological’ and ‘semantic’ motivation are not just two types (Ullmann 1966), but two interrelated dimensions of the problem of lexical motivation. For instance, Fr. poire ‘pear’ — poirier ‘pear-tree’ expresses the same cognitive relation as the polysemy of Russ. gruša, and, at the same time, polysemy is only one formal device among others expressing cognitive relations that underlie lexical motivation. So the two dimensions of formal and cognitive relations in motivation only exist in combination. A sub-dimension of the formal aspect of motivation is the degree of formal transparency (cf. Fr. jouer ‘to play a game’ — jeu ‘game’). This factorization in different dimensions leads to a universally applicable grid for the description of lexical motivation. As a first step of a future comparative research project of lexical motivation in different languages it is applied to the 500 most frequent lexical words of French and yields a systematic motivational profile of French high-frequency vocabulary. In Section 5.3 the French pilot study is discussed in view of an approach to lexical typology which could be applied to any other language.
Synthesis, Biological Testing, and Binding Mode Prediction of 6,9-Diarylpurin-8-ones as p38 MAP Kinase Inhibitors
2007-04-06

Based on the purine scaffold of ATP, derivatives of 6,9-diarylpurine-8-one were prepared and tested for their ability to inhibit p38 MAP kinase, a key enzyme in the cellular regulation of proinflammatory cytokines. The inhibitor design combines the purine system of the authentic cosubstrate ATP with various phenyl moieties to explore the selectivity for the two hydrophobic regions of the kinase's ATP-binding cleft. The present study indicates a new binding mode of our scaffold to p38 MAP kinase, which comprises the desired structural features of ATP and the N-phenyl-N-purin-6-yl ureas previously published by Wan et al. Combinations of Autodock and FlexX docking with different scoring functions were used to assess the postulated binding mode. The predictive power of different docking-scoring combinations was determined. The presented results may form a solid basis for further optimization cycles since our theoretical findings are consistent with our experimental binding data and supported by the literature.
Atom Interferometer Based on Phase Coherent Splitting of Bose-Einstein Condensates with an Integrated Magnetic Grating
2007-04-06

We report the phase coherent splitting of Bose-Einstein condensates by means of a phase grating produced near the surface of a microelectronic chip. A lattice potential with a period of 4 mum is generated by the superposition of static and oscillating magnetic fields. Precise control of the diffraction is achieved by controlling the currents in the integrated conductors. The interference of overlapping diffraction orders is observed after 8 ms of propagation in a harmonic trap and subsequent ballistic expansion of the atomic ensemble. By analyzing the interference pattern we show a reproducible phase relation between the diffraction orders with an uncertainty limited by the resolution of the diffraction grating.
Gravitational radiation from collapsing magnetized dust
2007-04-06

In this article we study the influence of magnetic fields on the axial gravitational waves emitted during the collapse of a homogeneous dust sphere. We found that while the energy emitted depends weakly on the initial matter perturbations it has strong dependence on the strength and the distribution of the magnetic field perturbations. The gravitational wave output of such a collapse can be up to an order of magnitude larger or smaller calling for detailed numerical 3D studies of collapsing magnetized configurations.
Linking lateral interactions in flicker perception to lateral geniculate nucleus cell responses
2007-04-06

The perception of flicker strength in a circular stimulus can be changed by altering the relative temporal phase of a simultaneously flickering surrounding annulus: perceived flicker is weak when the two stimuli are modulated in‐phase and strong when the two are modulated in counter‐phase. Previously, we found that responses of single neurons in the monkey lateral geniculate nucleus (LGN) to such stimuli resemble the psychophysical data. On the basis of the resemblance in data, it was proposed that the physiological basis for the flicker perception may be present as proximal as the LGN. To strengthen this hypothesis, we simulated the response of an array of LGN neurons, the receptive fields (RFs) of which are covered by the stimulus. The simulations were based upon single‐cell recordings in the LGN of anaesthetized marmosets ( Callithrix jacchus ) using the same stimuli as previously. The measurements were repeated for different spatial displacement between the stimulus and the RF. The responses depended upon the spatial displacement and the relative phase between centre and surround stimuli. The neuronal responses can be adequately described by a difference‐of‐Gaussians (DOG) model with a time delay in the RF surround. The model responses at different displacements can be considered to be identical to the output of an array of ideal and identical LGN cells with different RF locations. To be able to describe physiological and psychophysical data, obtained at different stimulus contrasts, it was necessary to consider previously described non‐linear interactions between the RF centres and surrounds. We applied a spatial peak‐to‐trough detector with a subsequent saturation and threshold to simulate a simple cortical decision mechanism. The output of this peak‐to‐trough detector could adequately describe the psychophysical data.
<title>Theoretical and experimental study of migration-assisted upconversion in high-concentration erbium doped silica fibers</title>
2007-04-06

We report a new experimental and theoretical characterization of high concentration erbium doped silica fibers. Applying a pair-correlation function of erbium ions that is known from x-ray absorption fine structure spectroscopy, we develop a new statistical model of migration-assisted upconversion in erbium doped fibers. We find that the new model provides accurate fitting to our experimental data for the upconversion coefficient as a function of the metastable level population.
Amyloid precursor protein intracellular domain modulates cellular calcium homeostasis and ATP content
2007-04-10

Abstract Consecutive cleavages of amyloid precursor protein (APP) generate APP intracellular domain (AICD). Its cellular function is still unclear. In this study, we investigated the functional role of AICD in cellular Ca 2+ homeostasis. We could confirm previous observations that endoplasmic reticulum Ca 2+ stores contain less calcium in cells with reduced APP γ‐secretase cleavage products, increased AICD degradation, reduced AICD expression or in cells lacking APP. In addition, we observed an enhanced resting cytosolic calcium concentration under conditions where AICD is decreased or missing. In view of the reciprocal effects of Ca 2+ on mitochondria and of mitochondria on Ca 2+ homeostasis, we analysed further the cellular ATP content and the mitochondrial membrane potential. We observed a reduced ATP content and a mitochondrial hyperpolarisation in cells with reduced amounts of AICD. Blockade of mitochondrial oxidative phosphorylation chain in control cells lead to similar alterations as in cells lacking AICD. On the other hand, substrates of Complex II rescued the alteration in Ca 2+ homeostasis in cells lacking AICD. Based on these observations, our findings indicate that alterations observed in endoplasmic reticulum Ca 2+ storage in cells with reduced amounts of AICD are reciprocally linked to mitochondrial bioenergetic function.
Axial Halogen Ligand Effect on Photophysics and Optical Power Limiting of Some Indium Naphthalocyanines
2007-04-10

Three axially substituted complexes, 2,3-octa(3,5-di-tert-butylphenoxy)-2,3-naphthalocyaninato indium chloride (1a), 2,3-octa(3,5-di-tert-butylphenoxy)-2,3-naphthalocyaninato indium bromide (1b), and 2,3-octa(3,5-di-tert-butylphenoxy)-2,3-naphthalocyaninato indium iodide (1c) have been synthesized and their photophysical properties have been investigated. Optical power limiting of nanosecond (ns) and picosecond (ps) laser pulses at 532 nm using these complexes has been demonstrated. All complexes display strong Q(0,0) absorption and measurable emission in the near-infrared region and exhibit strong excited-state absorption in the range of 470-700 nm upon ns laser excitation. The different axial ligands show negligible effect on the linear absorption, emission, and transient difference absorption spectra. However, the excited-state lifetime, triplet excited-state quantum yield, and efficiency to generate singlet oxygen are affected significantly by the heavier axial ligand. Brominated and iodinated complexes 1b and 1c show higher triplet excited-state quantum yield, while chlorinated complex 1a has longer excited-state lifetime and is more efficient in generating singlet oxygen. The iodinated complex 1c displayed the best optical limiting due to the higher ratio of excited-state absorption cross section to ground state absorption cross section (sigma(eff)/sigma(0)).
Synthesis and Conformational Analysis of Geodiamolide Analogues
2007-04-10

Abstract Starting with the ω‐hydroxy and ω‐amino acid derivatives 13 and 21 , the two closely related geodiamolide analogs 32 and 35 , respectively, were prepared. Compared to the natural cyclodepsipeptide geodiamolide ( 1 ), the macrocycles 32 and 35 have a smaller ring size (17‐ vs. 18‐membered). Conformational analysis by ROESY spectroscopy and molecular dynamics simulation revealed that the reduced ring size causes the polypropionate sector to flip with regard to the geodiamolide conformation.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Characterization of Vanadium(IV) and (V) Complexes with 2‐Hydroxy‐acetophenone‐semicarbazone (H2hasc) as Ligand. X‐Ray Crystal Structures of [VO2(H2hasc)] and [VO2(Hhasc)]
2007-04-10

Abstract Three novel vanadium complexes with pharmacologically active ligands were synthesized and characterized: [V IV O(acac)(Hhasc)], [V IV O 2 (H 2 hasc)], and [V V O 2 (Hhasc)], where H 2 hasc = 2‐Hydroxy‐acetophenone‐semicarbazone. The analytical methods used included FTIR, 1 H‐, 13 C‐, 51 V‐NMR and EPR spectroscopies, elemental analysis and X‐ray diffractometry from single crystals. The crystal and molecular structures of [V IV O 2 (H 2 hasc)] and [V V O 2 (Hhasc)] were determined. [V IV O 2 (H 2 hasc)] crystallizes monoclinic [P2 1 /c, Z = 4, a = 783.4(2), b = 1024.9(2), c = 1365.5(3) pm, β = 99.506(14)°]. The (VO 2 ) 2+ core is coordinated to a neutral O , N , O ‐tridentate unit of the H 2 hasc ligand, with the vanadium atom showing a square pyramidal coordination sphere. In the crystal of [V V O 2 (Hhasc)], triclinic [ , Z = 4, a = 858.73(11), b = 967.39(5), c = 1318.63(12) pm, α = 97.423(5), β = 101.590(6), γ = 98.144(5)°], two symmetry independent (VO 2 ) + cores are observed. Each of them coordinates to a monodeprotonated Hhasc − unit, in a O , N , O ‐tridentate mode. One assumes a square pyramidal geometry for the pentacoordinate vanadium(V) center. An additional interaction is observed for the other one, involving the phenolate oxygen atom from a symmetry related unit, resulting in a [5+1]‐coordination number for the transition metal atom.
Stanna‐closo‐dodecaborate: The Crystal Structure of [Li(thf)3]2[SnB11H11], Vibrational Spectroscopy, Thermal Analysis and DFT Calculations
2007-04-10

Abstract The lithium salt of stanna‐ closo ‐dodecaborate was prepared and single‐crystalline material was obtained from tetrahydrofurane. The salt crystallizes as [Li(thf) 3 ] 2 [SnB 11 H 11 ] in the monoclinic space group P 2 1 /c ( a = 15.0608(10) Å, b = 14.0778(8) Å, c = 18.3890(12) Å and β = 110.324(5)°) and both lithium ions are coordinated to triangular cluster faces via B–H–Li bonds. DFT calculations in combination with a natural population analysis reveal that the tin vertex exhibits a positive partial charge while all boron atoms of the stannaborate cluster carry a negative charge. The boron atoms of the first B 5 ‐belt display the largest negative partial charges. Raman and IR spectra of the cesium salt of [SnB 11 H 11 ] 2− reveal that the cluster breathing modes which involve the tin vertex are found at around 250 cm −1 . Furthermore, the thermal stability of the group‐14‐heteroborate is remarkably large with a decomposition temperature of above 900 °C as determined with TG/DTA measurements.
Zr50Sc12O43N50 and Zr3Sc4N8 – Synthesis, Neutron Powder Diffraction and Raman Spectroscopy
2007-04-10

Abstract The nitridation of Zr 50 Sc 12 O 118 (Zr 0.807 Sc 0.193 O 1.90 ), an anion deficient fluorite related compound, with ammonia yields at 1100 °C a green product with composition Zr 1.613 Sc 0.387 O 1.387 N 1.613 . This compound crystallizes cubic in space group ( a = 1007.8(5) pm) and is isostructural to Bixbyite with statistical distribution of Zr/Sc at the cation and of O/N at the anion sites. These are the results of Rietveld refinements from a powder neutron diffraction experiment. If Zr 3 Sc 4 O 12 (Zr 0.429 Sc 0.571 O 1.714 ), an educt with another Zr/Sc ratio, is nitridated with ammonia the reaction path shows again the formation of a compound with a bixbyite structure, but finally at 1200 °C a red nitride with the composition Zr 3 Sc 4 N 8 (Zr 0.375 Sc 0.5 N) is formed. This compound has a cation deficient NaCl type structure (space group is ) with a = 452.8(1) pm. Neutron diffraction revealed again no ordering on the cation sites. Both compounds show an unperturbed N≡N stretching frequency in their Raman spectrum at 2327 cm −1 . Zr 3 Sc 4 N 8 exhibits at 1552 cm −1 a second sharp line which was assigned to a N 2 2− moiety.
Synthese und Kristallstrukturen von [p‐Me3NC6H4HgOC(O)Me][MeOSO3] und [(p‐Me3NC6H4)2Hg][HgI4]
2007-04-10

Abstract Syntheses and Crystal Structures of [p‐Me 3 NC 6 H 4 HgOC(O)Me][MeOSO 3 ] and [(p‐Me 3 NC 6 H 4 ) 2 Hg][HgI 4 ] The carbene complexes [p‐Me 3 NC 6 H 4 HgOC(O)CH 3 ][MeOSO 3 ] ( 5 ) and [(p‐Me 3 NC 6 H 4 ) 2 Hg][HgI 4 ] ( 7 ) are obtained by alkylation of Me 2 NC 6 H 4 HgOC(O)Me ( 4 ) with Me 2 SO 4 or MeI. The crystal structures of 5 and 7 reveal the expected presence of Hg‐C single bonds in both complexes.
Zwei Nitridchloride des Wolframs: W2NCl8 und W2NCl9
2007-04-10

Abstract Two Tungsten Nitride Chlorides: W 2 NCl 8 and W 2 NCl 9 A solid state reaction of tungsten(VI)chloride and cyanamide yielded black crystals of W 2 NCl 8 and red plate‐like crystals of W 2 NCl 9 . The structures of these compounds were determined by single crystal X‐ray diffraction. The crystal structure of W 2 NCl 8 contains [Cl 2/2 Cl 3 WNWCl 3 Cl 2/2 ]‐units forming chains along the c ‐axis. The tungsten atoms are linked by a symmetric nitrido bridge (d(W–N) = 1.8203(4) Å). The crystal structure of W 2 NCl 9 contains a dichloro‐bridged dimer of a nitride‐bridged ditungsten unit [Cl 5 WNWCl 3 Cl 2/2 ] 2 with two different W–N distances of 1.726(9) Å and 2.012(9) Å.
Rapid detection of Pfcrt and Pfmdr1 mutations in Plasmodium falciparum isolates by FRET and in vivo response to chloroquine among children from Osogbo, Nigeria
2007-04-11

Abstract Background Chloroquine (CQ) has been in use in Africa for a long time. Because of misuse, this drug has now lost its efficacy due to the emergence of resistance strains in most parts of Africa. Recently, it was shown that after chloroquine has been withdrawn from the market, chloroquine-sensitive Plasmodium falciparum re-emerged and chloroquine could again be used successfully as an antimalarial. Surveillance of parasite populations is, therefore, important to decide whether chloroquine could be re-introduced. Methods To estimate the prevalence of the most pivotal polymorphisms, including Pfcrt K76T, Pfmdr1 N86Y and Pfmdr1 Y184F mutations, and their contributions to the outcome of CQ treatment, isolates from Osogbo Western Nigeria were tested using the Fluorescence Resonance Energy Transfer (FRET) method on a real-time PCR instrument. Results 116 children with acute uncomplicated P. falciparum malaria infections were treated with the standard dosage of CQ and followed-up for 28 days. Blood samples were collected on filter paper at enrollment and during follow-up for identification of parasite carrying the chloroquine resistant transporter ( pfcrt ) and P. falciparum -multi drug resistance ( pfmdr1 ) gene mutations. Parasitological assessment of response to treatment showed that 62% of the patients were cured and 38% failed the CQ treatment. The presence of single mutant pfcrt (T76) alleles (P = 0.003) and in combination with mutant pfmdr1 Y86 (P = 0.028) was significantly associated with in vivo CQR. No other mutation on its own or in combinations was significantly associated with treatment outcome. Mutant pfcrt was more prevalent in both pre- and post-treatment isolates. No association was observed between age or initial level of parasitaemia and chloroquine treatment outcome. Conclusion The result established the usefulness and accuracy of real time PCR in pfcrt and pfmdr1 mutation detection and also give further evidence to the reliability of the pfcrt T76 point mutation as a molecular marker for CQ resistance.
Calcineurin inhibitors and rapamycin: cancer protection or promotion?
2007-04-11

Abstract: Since the introduction of cyclosporin A (CsA) in the early 1980s, the use of immunosuppressants has markedly increased. Already established drugs have proved effective in the treatment of a wide range of diseases outside transplantation medicine and new immunosuppressants have been developed for more specific indications such as psoriasis and atopic dermatitis. Patients in transplantation medicine as well as in dermatology have benefited significantly from systemic and topical application of both new and established drugs. But are these drugs without risks? Cancer‐protecting effects have been reported for some of the available immunosuppressants. Conversely, other publications and the issue of a black box warning by the US Food and Drug Administration have increased concerns about cancer‐promoting effects. Knowledge of the specific effects as well as adverse effects is paramount to ensure an application that is safe and beneficial for the patient. Here we review the mechanisms of action and therapeutic potential, and critically review recent literature with respect to possible carcinogenic side effects of systemic and topical CsA, tacrolimus, pimecrolimus and rapamycin.
Pegvisomant Treatment in Gigantism Caused by a Growth Hormone-secreting Giant Pituitary Adenoma
2007-04-11

Pegvisomant is a potent treatment option in patients with pituitary gigantism. In patients who do not respond to somatostatin analogues, knowledge of the SST receptor status may shorten the time to initiation of pegvisomant treatment.