julilili42/papers huggingface dataset:
Vibration pattern of the organ of Corti up to 50 kHz: Evidence for resonant electromechanical force
2004-12-10

Electromechanical force derived from the soma of the outer hair cell has long been postulated as the basis of the exquisite sensitivity of the cochlea. The problem with this postulate is that the electrical source and mechanical load for the electromechanical outer hair cell might be severely attenuated and phase-shifted by the electrical impedance of the cell and the mechanical impedance of the organ of Corti, respectively. Until now, it has not been possible to experimentally derive the high-frequency electrically induced force at the reticular lamina when the cells are embedded within the organ of Corti. In the study reported here, we succeeded in determining the frequency spectrum of the force up to 50 kHz. This was achieved by measuring both the electrically induced velocity and the mechanical impedance at different radial positions on the reticular lamina without tectorial membrane and with clamped basilar membrane. Velocity was measured with a laser interferometer and impedance, with a magnetically driven atomic force cantilever. The electromechanical force, normalized to the electric current density, exhibited a broad amplitude maximum at 7–20 kHz with a quality factor, Q 3dB , of 0.6 - 0.8. The displacement response was independent of frequency up to 10–20 kHz. The force response compensates for the viscoelastic impedance of the organ of Corti, extending the amplitude response of the organ to high frequencies. It is proposed that the electrical phase response of the cell is compensated with Zwislocki's original mechanism of a parallel resonance in the tectorial membrane–stereocilia complex.
Early Detection of Toxoplasma Infection by Molecular Monitoring of Toxoplasma gondii in Peripheral Blood Samples after Allogeneic Stem Cell Transplantation
2004-12-13

Toxoplasmosis occurs more commonly after HSCT than has previously been suggested, and routine PCR testing of peripheral blood specimens may be an appropriate tool for guiding preemptive therapy in patients at very high risk of developing invasive disease.
Detection of the naturalαdecay of tungsten
2004-12-13

The natural alpha decay of 180W has been unambiguously detected for the first time. The alpha peak is found in a (gamma,beta and neutron)-free background spectrum. This has been achieved by the simultaneous measurement of phonon and light signals with the CRESST cryogenic detectors. A half-life of T1/2 = (1.8 +- 0.2) x 10^18 y and an energy release of Q = (2516.4 +- 1.1 (stat.) +- 1.2 (sys.)) keV have been measured. New limits are also set on the half-lives of the other naturally occurring tungsten isotopes.
Deformed quasiparticle random phase approximation formalism for single- and two-neutrino doubleβdecay
2004-12-13

We use a deformed QRPA formalism to describe simultaneously the energy\\ndistributions of the single beta Gamow-Teller strength and the two-neutrino\\ndouble beta decay matrix elements. Calculations are performed in a series of\\ndouble beta decay partners with A = 48, 76, 82, 96, 100, 116, 128, 130, 136 and\\n150, using deformed Woods-Saxon potentials and deformed Skyrme Hartree-Fock\\nmean fields. The formalism includes a quasiparticle deformed basis and residual\\nspin-isospin forces in the particle-hole and particle-particle channels. We\\ndiscuss the sensitivity of the parent and daughter Gamow-Teller strength\\ndistributions in single beta decay, as well as the sensitivity of the double\\nbeta decay matrix elements to the deformed mean field and to the residual\\ninteractions. Nuclear deformation is found to be a mechanism of suppression of\\nthe two-neutrino double beta decay. The double beta decay matrix elements are\\nfound to have maximum values for about equal deformations of parent and\\ndaughter nuclei. They decrease rapidly when differences in deformations\\nincrease. We remark the importance of a proper simultaneous description of both\\ndouble beta decay and single Gamow-Teller strength distributions. Finally, we\\nconclude that for further progress in the field it would be useful to improve\\nand complete the experimental information on the studied Gamow-Teller strengths\\nand nuclear deformations.\\n
Polymorphous Vascular Patterns in Dermoscopy as a Sign of Malignant Skin Tumors
2004-12-14

&lt;i&gt;Background:&lt;/i&gt; Using dermoscopy (dermatoscopy, epiluminescence microscopy), malignant skin tumors can be detected earlier and unnecessary excisions of benign tumors can be avoided. &lt;i&gt;Objective:&lt;/i&gt; Description of the dermoscopic vascular patterns of an amelanotic melanoma and a porocarcinoma. &lt;i&gt;Methods:&lt;/i&gt; Dermoscopy of an amelanotic melanoma and a porocarcinoma at 10-fold magnification. &lt;i&gt;Results:&lt;/i&gt; On dermoscopy polymorphous vascular patterns with pinpoint and hairpin-like vessels were seen. &lt;i&gt;Conclusion:&lt;/i&gt; A reddish tumor without any pigmented network, globules or streaks but with polymorphous vascular patterns must be considered a malignant melanocytic or nonmelanocytic skin tumor.
Genetics of nicotine and tobacco dependency
2004-12-14

Abstract The prevalence of smoking in our society is subject to many social influences. Heavy and regular smoking and the development of nicotine dependence, however, are determined not only by social factors but also by individual psychological and biological factors. Recent epidemiological and molecular genetic studies have provided evidence that nicotine dependence is, at least partially, genetically determined. Regular smoking and more particularly heavy smoking have been attributed with a high probability to genetic factors. The development of nicotine dependence results from the direct effect of nicotine on nicotinergic acetylcholine receptors, and perhaps more importantly, the dopaminergic transmitter system. The nucleus accumbens, an important part of the dopaminergic reward system, appears to play a particularly important role in nicotine dependence. A possibly relevant genetic variability in the dopaminergic system was found in the D2 dopamine receptor gene (DRD2) of alcoholics and heavy smokers...
Variable solid state aggregations in a series of (isocyanide)gold(i) halides with the novel trimethylamine-isocyanoborane adduct
2004-12-14

This paper provides evidence that the degree of aurophilic character and resulting solid state arrangement observed in (isocyanide)gold(I) halides is in part dependent on the nature of halide substituent. In particular, we report here the synthesis of a series of novel (isocyanide)gold(I) halides involving trimethylamine-isocyanoborane, an unusual 'zwitterionic' isocyanide that is comparable to the more familiar methyl isocyanide, but potentially more strongly Lewis basic. The reaction of chloro(dimethyl sulfide)gold(I) and the isocyanoborane species, (RNC)(R =(H3C)3NB(H)2), gives the novel crystalline adduct [(RNC)AuCl] (1). Treatment of 1 in an organic phase with aqueous KBr effected substitution of the chloride to give the bromide analogue [(RNC)AuBr] (2). The structures of 1 and 2 were determined by X-ray crystallography to be isostructural, consisting of a zigzag topology of chains of monomers, where adjacent gold(I) centres interact aurophilically. However, similar reaction of 1 with KI solution affords the unusual and unexpected compound, [(RNC)2Au][AuI2] (3). This iodide 3, is a linear chain polymer of alternating anion, cation units that is formed via ligand redistribution. The complexes 1-3 all fluoresce in the presence of UV light; the fluorescence of 3 being most prevalent at room temperature. The free trimethylamine-isocyanoborane ligand, the dimeric structures of compounds 1,2 and the thermodynamic stabilities of the dimers in the gas phase were studied by density functional and ab initio calculations at various levels of theory. The theoretical results are compared to the corresponding experimental data.
Circulating Tumor Cells in Patients with Breast Cancer Dormancy
2004-12-15

Abstract Purpose: The purpose of this study was to test the hypothesis that circulating tumor cells (CTCs) are present in patients many years after mastectomy without evidence of disease and that these CTCs are shed from persisting tumor in patients with breast cancer dormancy. Experimental Design: We searched for CTCs in 36 dormancy candidate patients and 26 age-matched controls using stringent criteria for cytomorphology, immunophenotype, and aneusomy. Results: Thirteen of 36 dormancy candidates, 7 to 22 years after mastectomy and without evidence of clinical disease, had CTCs, usually on more than one occasion. Only 1 of 26 controls had a possible CTC (no aneusomy). The statistical difference of these two distributions was significant (exact P = 0.0043). The CTCs in patients whose primary breast cancer was just removed had a half-life measured in 1 to 2.4 hours. Conclusions: The CTCs that are dying must be replenished every few hours by replicating tumor cells somewhere in the tissues. Hence, there appears to be a balance between tumor replication and cell death for as long as 22 years in dormancy candidates. We conclude that this is one mechanism underlying tumor dormancy.
Loss of pain perception in diabetes is dependent on a receptor of the immunoglobulin superfamily
2004-12-15

Molecular events that result in loss of pain perception are poorly understood in diabetic neuropathy. Our results show that the receptor for advanced glycation end products (RAGE), a receptor associated with sustained NF-kappaB activation in the diabetic microenvironment, has a central role in sensory neuronal dysfunction. In sural nerve biopsies, ligands of RAGE, the receptor itself, activated NF-kappaBp65, and IL-6 colocalized in the microvasculature of patients with diabetic neuropathy. Activation of NF-kappaB and NF-kappaB-dependent gene expression was upregulated in peripheral nerves of diabetic mice, induced by advanced glycation end products, and prevented by RAGE blockade. NF-kappaB activation was blunted in RAGE-null (RAGE(-/-)) mice compared with robust enhancement in strain-matched controls, even 6 months after diabetes induction. Loss of pain perception, indicative of long-standing diabetic neuropathy, was reversed in WT mice treated with soluble RAGE. Most importantly, loss of pain perception was largely prevented in RAGE(-/-) mice, although they were not protected from diabetes-induced loss of PGP9.5-positive plantar nerve fibers. These data demonstrate, for the first time to our knowledge, that the RAGE-NF-kappaB axis operates in diabetic neuropathy, by mediating functional sensory deficits, and that its inhibition may provide new therapeutic approaches.
Vδ1 T Lymphocytes from B-CLL Patients Recognize ULBP3 Expressed on Leukemic B Cells and Up-Regulated by Trans -Retinoic Acid
2004-12-15

Abstract We analyzed 38 untreated patients with chronic lymphocytic leukemia of B-cell type (B-CLL): 24 low-, 8 intermediate-, and 6 high-risk stage. In 15 patients (13 low risk and 2 intermediate risk), circulating Vδ1 T lymphocytes were significantly increased (100 to 300 cells/μL) compared with most intermediate, all high-risk stage, and 15 healthy donors (50 to 100 cells/μL). We studied these Vδ1 T lymphocytes and observed that they proliferated in vitro and produced tumor necrosis factor α or IFN-γ in response to autologous leukemic B cells but not to normal lymphocytes. However, they were unable to kill resting autologous B cells, which lack the MHC-related MIC-A antigen and express low levels of the UL16-binding protein (ULBP) 3 and undetectable levels of ULBP1, ULBP2, and ULBP4. All these molecules are reported ligands for the NKG2D receptor, which is expressed by γδ T cells and activates their cytolytic function. The Vδ1 T lymphocytes studied were able to lyse the ULBP3+ C1R B-cell line upon transfection with MIC-A. More importantly, they also lysed autologous B-CLL cells when transcription and expression of MIC-A or up-regulation of ULBP3 were achieved either by activation or by exposure to trans-retinoic acid. The NKG2D receptor expressed on Vδ1 T cells was involved in the recognition of B-CLL. Finally, in six patients with low numbers of circulating Vδ1 T cells and undetectable ULBP3, the disease progressed over 1 year, whereas no progression occurred in patients with high Vδ1 T lymphocytes and detectable/inducible ULBP3. These data suggest that Vδ1 T lymphocytes may play a role in limiting the progression of B-CLL.
Occurrence of hopanoid lipids in anaerobicGeobacterspecies
2004-12-15

Geobacter metallireducens and G. sulfurreducens have been classified as strictly anaerobic bacteria which grow and thrive in subsurface and sediment environments. Hopanoids are pentacyclic triterpenoid lipids and are important for bacterial membrane stability and functioning. Hopanoids predominantly occur in aerobically growing bacteria of oxic environments. They rarely have been found in facultatively anaerobic bacteria and, to date, not at all in strict anaerobes. Our research shows that anaerobically grown G. metallireducens and G. sulfurreducens bacteria contain a range of hopanoid lipids, such as diploptene (i.e. hop-22(29)-ene) and hop-21-ene, and more complex, elongated hopanoids. In geological formations, diagenetic derivatives of hopanoids are widely used as biomarkers and are recognized as molecular fossils of bacterial origin. To date, these biomarkers have largely been interpreted as those derived from ancient oxic environments. Our findings presented here suggest that this interpretation needs to be re-evaluated. In addition to the origin in oxic environments, 'geohopanoids' may originate from ancient anaerobic environments as well.
Russulaceae and Thelephoraceae form ectomycorrhizas with members of the Nyctaginaceae (Caryophyllales) in the tropical mountain rain forest of southern Ecuador
2004-12-15

* Three members of the Nyctaginaceae, two Neea species and one Guapira species, occurred scattered within a very species-rich neotropical mountain rain forest. The three species were found to form ectomycorrhizas of very distinctive characters, while all other tree species examined formed arbuscular mycorrhizas. * The ectomycorrhizas were structurally typified according to light and transmission electron microscope investigations. The internal transcribed spacer (ITS) rDNA and part of the nuclear large subunit (LSU, 28S) rDNA of the mycorrhiza forming fungi were amplified and sequenced. Phylogenetic analyses were carried out. * Neea species 1 was found to form typical ectomycorrhizas with five different fungal species, Russula puiggarii, Lactarius sp., two Tomentella or Thelephora species, and one ascomycete. Neea species 2 and the Guapira species were associated with only one fungus each, a Tomentella/Thelephora species clustering closely together in an ITS-neighbour-joining tree. The long and fine rootlets of the Guapira species showed proximally a hyphal mantle and a Hartig net, but distally intracellular fungal colonization of the epidermis and root hair development. The ectomycorrhizal segments of the long roots of Neea species 2 displayed a hyphal mantle and a Hartig net around alive root-hair-like outgrowths of the epidermal cells. * The distribution and the evolution of ectomycorrhizas in the predominantly neotropic Nyctaginaceae are discussed.
Large-Scale Association Study Identifies ICAM Gene Region as Breast and Prostate Cancer Susceptibility Locus
2004-12-15

Abstract We conducted a large-scale association study to identify genes that influence nonfamilial breast cancer risk using a collection of German cases and matched controls and &amp;gt;25,000 single nucleotide polymorphisms located within 16,000 genes. One of the candidate loci identified was located on chromosome 19p13.2 [odds ratio (OR) = 1.5, P = 0.001]. The effect was substantially stronger in the subset of cases with reported family history of breast cancer (OR = 3.4, P = 0.001). The finding was subsequently replicated in two independent collections (combined OR = 1.4, P &amp;lt; 0.001) and was also associated with predisposition to prostate cancer in an independent sample set of prostate cancer cases and matched controls (OR = 1.4, P = 0.002). High-density single nucleotide polymorphism mapping showed that the extent of association spans 20 kb and includes the intercellular adhesion molecule genes ICAM1, ICAM4, and ICAM5. Although genetic variants in ICAM5 showed the strongest association with disease status, ICAM1 is expressed at highest levels in normal and tumor breast tissue. A variant in ICAM5 was also associated with disease progression and prognosis. Because ICAMs are suitable targets for antibodies and small molecules, these findings may not only provide diagnostic and prognostic markers but also new therapeutic opportunities in breast and prostate cancer.
Loss of pain perception in diabetes is dependent on a receptor of the immunoglobulin superfamily
2004-12-15

Molecular events that result in loss of pain perception are poorly understood in diabetic neuropathy. Our results show that the receptor for advanced glycation end products (RAGE), a receptor associated with sustained NF-κB activation in the diabetic microenvironment, has a central role in sensory neuronal dysfunction. In sural nerve biopsies, ligands of RAGE, the receptor itself, activated NF-κBp65, and IL-6 colocalized in the microvasculature of patients with diabetic neuropathy. Activation of NF-κB and NF-κB–dependent gene expression was upregulated in peripheral nerves of diabetic mice, induced by advanced glycation end products, and prevented by RAGE blockade. NF-κB activation was blunted in RAGE-null (RAGE(–/–)) mice compared with robust enhancement in strain-matched controls, even 6 months after diabetes induction. Loss of pain perception, indicative of long-standing diabetic neuropathy, was reversed in WT mice treated with soluble RAGE. Most importantly, loss of pain perception was largely prevented in RAGE(–/–) mice, although they were not protected from diabetes-induced loss of PGP9.5-positive plantar nerve fibers. These data demonstrate, for the first time to our knowledge, that the RAGE–NF-κB axis operates in diabetic neuropathy, by mediating functional sensory deficits, and that its inhibition may provide new therapeutic approaches.
Short and Long Range Magnetic Ordering in β-MnO2–A Temperature Study–
2004-12-15

The magnetic long range ordering (LRO) and short range ordering (SRO) in β-MnO 2 has been studied by neutron powder diffraction. Below T N =92.5(1) K β-MnO 2 has an incommensurate modulated magnetic LRO with temperature dependent propagation vector length k z . The values of k z show a maximum, corresponding to k z = (2/7) + 0.0120(1), near 90 K. The c lattice constant has a minimum near T N . The temperature dependence of the ordered magnetic moment shows a critical behavior M ( T )∝( T N - T ) β with β=0.18(2). β-MnO 2 has also a magnetic SRO from 50 up to 300 K as conjectured by Sato et al. [Phys. Rev. B 61 (2000) 3563]. The SRO magnetic correlation length of about 9.5(1.0) Å do not change with temperature. The Q -position of the SRO contribution decrease by 20% on warming from 50 to 300 K.
3,4‐Methylenedioxymethamphetamine counteracts akinesia enantioselectively in rat rotational behavior and catalepsy
2004-12-15

Abstract We have shown recently that 3,4‐methylenedioxymethamphetamine (MDMA) has symptomatic antiparkinsonian activity in rodent models of Parkinson's disease. In search of its mechanism of action, we further investigated the enantiomers of MDMA in the rotational behavioral model and catalepsy test. Catalepsy testing was done in drug‐naive unlesioned animals. The parkinsonian symptoms rigor and akinesia (i.e., catalepsy) were induced by intraperitoneal administration of haloperidol 0.5 mg/kg and measured repeatedly as descent latency from a horizontal bar and a vertical grid. MDMA and both its enantiomers were effective in counteracting haloperidol‐induced catalepsy, but if given as racemic, the effects were more pronounced than with the enantiomers. For testing of rotational behavior, male Sprague Dawley rats were lesioned unilaterally with 6‐hydroxydopamine (6‐OHDA) at the medial forebrain bundle. Administration of S‐MDMA (5 mg/kg) produced ipsilateral rotations. R‐MDMA was far less effective in inducing ipsilateral rotations in 6‐OHDA unilaterally lesioned rats, but when S‐MDMA was given additionally rotations immediately increased. Regarding their overall antiparkinsonian effects, the S‐enantiomer of MDMA was more effective than its R‐congener. R‐MDMA was able to increase the actions of S‐MDMA. Synapse 55:148–155, 2005. © 2004 Wiley‐Liss, Inc.
The steady-state structure of accretion discs in central magnetic fields
2004-12-15

We develop a new analytic solution for the steady-state structure of a thin accretion disc under the influence of a magnetic field that is anchored to the central star. The solution takes a form similar to that of Shakura and Sunyaev and tends to their solution as the magnetic moment of the star tends to zero. As well as the Kramer's law case, we obtain a solution for a general opacity. The effects of varying the mass transfer rate, spin period and magnetic field of the star as well as the opacity model applied to the disc are explored for a range of objects. The solution depends on the position of the magnetic truncation radius. We propose a new approach for the identification of the truncation radius and present an analytic expression for its position.
Compensation of magnetic field distortions from paramagnetic instruments by added diamagnetic material: Measurements and numerical simulations
2004-12-16

In minimally invasive procedures guided by magnetic resonance (MR) imaging instruments usually are made of titanium or titanium alloys (e.g., nitinol), because other more MR‐compatible materials often cannot provide sufficient mechanical properties. Artifacts depending on susceptibility arise in MR images due to incorrect spatial encoding and intravoxel dephasing and thereby hamper the surgeon's view onto the region of interest. To overcome the artifact problem, compensation of the paramagnetic properties by diamagnetic coating or filling of the instruments has been proposed in the literature. We used a numerical modeling procedure to estimate the effect of compensation. Modeling of the perturbation of the static magnetic field close to the instruments reflects the underlying problem and is much faster and cost efficient than manufacturing prototypes and measuring artifact behavior of these prototypes in the MR scanner. A numerical model based on the decomposition of the susceptibility distribution in elementary dipoles was developed by us. The program code was written object oriented to allow for both maximum computational speed and minimum random access memory. We used System International units throughout the modeling for the magnetic field, allowing absolute quantification of the magnetic field disturbance. The field outside a simulated needlelike instrument, modeled by a paramagnetic cylinder (out of titan, ) of length 8.0 mm and of diameter 1.0 mm, coated with a diamagnetic layer (out of bismuth, ) of thickness 0, 0.1, 0.2, 0.3, and 0.4 mm, was found to be best compensated if the cross‐sectional area of the cylinder, multiplied by the absolute susceptibility value of the cylinder material, is equal to the cross‐sectional area of the coating, multiplied by the absolute susceptibility value of the coating material. At the extremity of the coated cylinder an uncompensated field distortion was found to remain. We studied various tip shapes and geometries using our computational model: Suitable diamagnetic coating or filling of paramagnetic instruments clearly reduced tip artifacts and diminished the dependency of artifact size on orientation of the instrument with respect to in the numerical studies. We verified the results of the simulations by measuring coated and uncoated titanium wires in a 1.5 T MR scanner.