bluuebunny/crossref_metadata_2025_split huggingface dataset:
Im Schatten Schwarzer Löcher: Theoretische Astrophysik
Authors: de Vries Andreas 
Published: April 2004

AbstractSchwarze Löcher werden im Rahmen der Allgemeinen Relativitätstheorie als Singularitäten beschrieben. Sie krümmen die Raumzeit in ihrer Umgebung so stark, dass Licht in einem bestimmten Abstand auf Kreis‐ oder Ellipsenbahnen um die Singularität herumläuft. Insofern werfen Schwarze Löcher vor einem hellen Hintergrund einen Schatten. Mit großen Teleskopen könnten diese zukünftig eventuell nachgewiesen werden und Informationen über die einzigen Eigenschaften Schwarzer Löcher liefern: Masse, Ladung und Rotation.
Atomkühlung mit Lichtresonatoren
Authors: Rempe Gerhard 
Published: April 2004

AbstractAlle bisherigen Verfahren zur Kühlung eines atomaren Gases funktionieren grundsätzlich nicht bei Molekülen. Eine Gruppe am Max‐Planck‐Institut für Quantenoptik in Garching hat kürzlich eine neue Methode entwickelt, mit der sich einzelne Atome zwischen zwei Spiegeln abbremsen lassen. Diese ist auch auf Moleküle anwendbar [1].
Wann uns Quantenteilchen klassisch erscheinen
Authors: Arndt Markus 
Published: April 2004

AbstractAtome und Moleküle weisen ebenso Welleneigenschaften auf wie beispielsweise Licht. Eine Eigenschaft, die mit wachsender Teilchengröße zunehmend schwerer zu beweisen ist. Eine Forschergruppe an der Universität Wien demonstrierte jüngst, wie auch die thermische Lichtemission von Molekülen den Wellencharakter unbeobachtbar macht [1].
Perspektive täuscht
Authors: Schlichting H. Joachim 
Published: April 2004

AbstractDie perspektivische Verkürzung täuscht bekanntlich Konvergenzen vor, wo keine sind. In größeren Entfernungen, in denen das binokulare räumliche Sehen nicht mehr funktioniert, ist die perspektivische Täuschung ein wesentliches Element der räumlichen Wahrnehmung. Der Dom Santa Maria del Fiore in Florenz bietet hierfür ein besonders beeindruckendes Beispiel. Mit diesem Beitrag beginnen wir eine Serie über Alltägliches und auf den zweiten Blick Verblüffendes.
Has the yo‐yo stopped? An assessment of human protein‐coding gene number
Authors: Southan Christopher 
Published: April 2004

AbstractSince the identification of ∼ 25 000 proteins from the draft human genome assembly in 2001, estimates of the total have oscillated between 30 000 and 70 000. The recently announced genome closure has not generated a consensus gene count despite this being a key parameter for many areas of biology including drug target discovery and characterization of the human proteome. Contrary to earlier predictions of constitutive under‐detection for eukaryotic genes, the latest model organism updates have produced minor increases in the worm but fly and yeast gene numbers have decreased. The postdraft, precompletion interval has produced large increases in human transcript coverage, continuous improvements in genome assembly and refinements in automated genomic annotation. Notably these enhancements have resulted in an Ensembl human protein‐coding gene number of 22 184, a decrease of 1862 since the first release. Longitudinal database surveys indicate that redundancy‐reduced human mRNA and protein collections are flattening out at ∼ 28 000, although Ensembl maps ∼ 20 000 known sequences. Observations suggest high‐throughput cloning projects are predominantly extending known genes or sampling new splice forms and novel protein discovery has slowed to a trickle. The hypothesis that substantial numbers of short proteins remain experimentally and computationally undetected in mammalian genomes is neither supported by sequence data nor by the extensive homology between mouse and human proteins. Aggregating the independent annotations for complete transcripts from seven completed human chromosomes extrapolates to ∼ 25 000 genes. The inclusion of partial putative genes would increase this to above 30 000 but recent data suggest these represent predominantly nonprotein‐coding transcripts. Mass spectrometry‐based proteomics has already verified more than 10% of human genes but has not identified significant numbers of unpredicted proteins. The available data are thus converging to a basal protein‐coding gene number well below 30 000, which could even be as low as 25 000.
Differential protein composition of bovine whey: A comparison of whey from healthy animals and from those with clinical mastitis
Authors: Hogarth Caroline J. , Fitzpatrick Julie L. , Nolan Andrea M. , Young Fiona J. , Pitt Andrew , Eckersall P. David 
Published: April 2004

AbstractDuring clinical mastitis in dairy cows, the quantity of milk produced decreases and the composition of the milk is altered. As the severity of inflammation associated with the disease increases, the chemical composition of milk approaches that of blood as a consequence of increased permeability of the blood mammary barrier, or de novo intramammary synthesis, as has been suggested for mammary associated serum amyloid A3. A better understanding of these events may provide new approaches for the diagnosis and treatment of mastitis. The objective of this study was to document the changes in the protein composition of milk during clinical mastitis using a proteomic approach, with the objective of identifying new diagnostic markers of mastitis. Whey from dairy cows with clinical mastitis was compared to whey from healthy animals by two‐dimensional gel electrophoresis (2‐DE) with colloidal Coomassie staining and matrix‐assisted desorption/ionization mass spectrometry. Increases in the concentrations of proteins of blood serum origin, including serotransferrin and albumin, were identified in mastitic whey compared to normal whey, while concentrations of the major whey proteins α‐lactalbumin and β‐lactoglobulin were reduced in mastitic whey. Mass spectrometry subsequently confirmed the location of albumin, α‐lactalbumin and β‐lactoglobulin on the 2‐DE gels at Mr/pI of 69 294/5.8, 14 200/4.5 and 19 883/4.9 respectively.
Prediction of disulfide‐bonded cysteines in proteomes with a hidden neural network
Authors: Martelli Pier Luigi , Fariselli Piero , Casadio Rita 
Published: April 2004

AbstractA hidden neural network‐based method is used to predict the bonding state of cysteines starting from the residue sequence of the protein chain. The method scores as high as 89% and 86% per cysteine residue and per protein, respectively, and in this overcomes other predictors of the same category. We then explore the efficacy of our predictor in computing the disulfide content of the whole proteome of Escherichia coli (K12 and O157), Aeropirum pernix, Thermotoga maritima, and Homo sapiens. We find that the percentage of extracellular disulfide containing proteins is higher than that of intracellular one, and that the human proteome is by far the one with the highest content of sulfur‐sulfur linkages in proteins.
Advances in the prediction of protein targeting signals
Authors: Schneider Gisbert , Fechner Uli 
Published: April 2004

AbstractEnlarged sets of reference data and special machine learning approaches have improved the accuracy of the prediction of protein subcellular localization. Recent approaches report over 95% correct predictions with low fractions of false‐positives for secretory proteins. A clear trend is to develop specifically tailored organism‐ and organelle‐specific prediction tools rather than using one general method. Focus of the review is on machine learning systems, highlighting four concepts: the artificial neural feed‐forward network, the self‐organizing map (SOM), the Hidden‐Markov‐Model (HMM), and the support vector machine (SVM).
Melting and crystallization behavior of poly(vinylidene fluoride) produced isothermally in the intercrystalline spaces of poly(ethylene terephthalate) from its blends
Authors: Rahman M. Habibur , Nandi Arun K. 
Published: April 2004

AbstractThe melting of isothermally crystallized poly(vinylidene fluoride) (PVF2), produced in the intercrystalline spaces of poly(ethylene terephthalate) (PET) from its blends, showed a unique behavior: the melting temperature decreased with the increasing crystallinity of PVF2 (i.e., with increasing crystallization time) for PVF2 volume fractions of 0.64 and 0.51. The melting temperature of already crystallized PET also decreased as the PVF2 crystallization progressed and the isothermal crystallization temperature of PVF2 increased. Separate reasons were proposed to account for these behaviors. The equilibrium melting temperatures of PVF2 in the blends, measured by the Hoffman–Weeks extrapolation procedure, were used to calculate the polymer–polymer interaction parameter (χ21); only the noncrystallized portion of PET contributing to the mixed amorphous phase was considered. The χ21value (−1.75) was lower than χ12 (−0.14), calculated from the melting temperature depression of PET. However, when they were normalized to the unit volumes of the respective components, the two values were found to be the same. The crystallization rate of PVF2 decreased with an increasing volume fraction of PET in the blend. The Avrami exponent increased for the volume fraction of PVF2 (0.77) and then progressively decreased with an increasing volume fraction of PET. A gradual change in the nature of the regime transition from regime II/regime I to regime III/regime II with increasing PET concentration was observed. The value of the chain‐extension factor of PVF2 significantly increased with an increase in the PET concentration in the blends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2215–2227, 2004
Therapeutic potential of curcumin in prostate cancer—IV: Interference with the osteomimetic properties of hormone refractory C4‐2B prostate cancer cells
Authors: Dorai Thambi , Dutcher Janice P. , Dempster David W. , Wiernik Peter H. 
Published: April 2004

AbstractBACKGROUNDThere is increasing evidence that the stringent selective pressure imposed by androgen ablation therapy on the residual prostate cancer cells may actually accelerate the development of the hormone refractory and bone metastatic phenotype. The propensity of prostate cancer to establish osseous metastases is very likely mediated by the osteomimetic properties of the prostate cancer cells. Prostate cancer cells acquire these “bone‐like” properties in order to survive in the bony microenvironment. This process is facilitated by common growth factor trophisms between the bone stromal cells, osteoblasts, and the prostate cancer cells wherein a number of growth factors and their receptors are involved. Thus, a general inhibition of the tyrosine kinase signaling pathways may have a therapeutic advantage in interfering with the metastatic potential of these prostate cancer cells. This study focuses on the potential of curcumin, a plant based non‐toxic tyrosine kinase inhibitor in interfering with the development of bone like properties of C4‐2B, a highly metastatic derivative of LNCaP prostate cancer cell line.METHODSC4‐2B prostate cancer cells were analyzed for their constitutive expression and ligand inducible activation of growth factor receptors such as EGF‐R and CSF1‐R. Expression of bone‐specific transcription factors such as Cbfa‐1 and the production of PTHRP were followed. The ability of the C4‐2B cells to mineralize under specific conditions was analyzed. The activation status of the transcription factor NF‐κB was also followed.RESULTSCurcumin inhibited the ligand‐stimulated autophosphorylation of EGF‐R and CSF1‐R that were crucially involved in the development of osteomimetic properties of C4‐2B cells. When C4‐2B cells were grown under promineralization conditions, curcumin prevented the formation of the mineralized nodules. It also inhibited the expression of the core‐binding factor a‐1 in C4‐2B cells which was responsible for the expression of several bone‐specific proteins. The IKK activity was severely impaired, showing marked NF‐κB inhibition. The experiments indicate that curcumin can also interfere with the development of the osteoblast and the osteoclast‐like properties by these prostate cancer cells.CONCLUSIONSThe highly metastatic C4‐2B prostate cancer cell line is already “programmed” to exhibit the bone‐like properties that would at least in part explain its affinity to set up osseous metastases. Curcumin is able to interfere with the osteoblastic component as well as the osteoclastic component of this phenotype, by interfering with the growth factor receptor pathways and by inhibiting the NF‐κB activation process. It is concluded that curcumin may inhibit the growth factor collaboration between the prostate cancer cells and the osteoblast/stromal cells, thus exhibiting a potential to prevent the establishment of bony metastases. © 2003 Wiley‐Liss, Inc.
Immunological monitoring during combination of patient‐oriented peptide vaccination and estramustine phosphate in patients with metastatic hormone refractory prostate cancer
Authors: Noguchi Masanori , Itoh Kyogo , Suekane Shigetaka , Morinaga Akiko , Sukehiro Aki , Suetsugu Norie , Katagiri Kazuko , Yamada Akira , Noda Shinshi 
Published: April 2004

AbstractBACKGROUNDAdditive antitumor effects could be achieved by combination of immunotherapy and cytotoxic agents with no or minimum suppression.METHODSThirteen patients positive for human leukocyte antigen (HLA)‐A24 or ‐A2 with metastatic hormone refractory prostate cancer (HRPC) who had failed to respond to the prior‐peptide vaccination were entered in the combined peptide vaccination and estramustine phosphate. Conducted immune monitoring on those 13 patients were mainly peptide‐specific cytotoxic T lymphocyte (CTL) precursor analysis by IFN‐γ productions and peptide‐reactive IgG by an enzyme‐linked immunosorbent assay (ELISA).RESULTSGrade 3 arrhythmia or cerebral infarction was observed in two cases, and Grade 1 or 2 dermatologic reaction at the vaccination sites was observed in all 13 cases. Eleven patients who received more than one cycle of treatment were eligible for immunological and clinical evaluation. There was no significant immunosuppression in most cases when the peptide and a half dose (280 mg/day) of estramustine were administrated, whereas severe immunosuppression was observed in the first two patients who received both the peptide and a full dose (560 mg/day) estramustine. Augmentation of peptide‐specific CTL precursors or peptide‐specific IgG was observed in 6 of 11 or 10 of 11 cases, respectively. Ten of 11 patients showed serum prostate‐specific antigen (PSA) level decrease from the baseline including 8 patients with a serum PSA level decrease of ≥50%.CONCLUSIONSThese results encouraged the further evaluation of the combination of peptide vaccination and low‐dose estramustine phosphate for metastatic HRPC patients. © 2004 Wiley‐Liss, Inc.
The ErbB signaling network is coordinately expressed and activated in the mouse prostate
Authors: Zhu Yun , Jones Frank E. 
Published: April 2004

AbstractBACKGROUNDThe ErbB family of receptor tyrosine kinases contribute to human prostate cancer, however, ErbB activity in the normal prostate requires further investigation. The mouse prostate may serve as an important model system to study the molecular mechanisms regulating ErbB signaling in the prostate.METHODSWe employed RT‐PCR and immunohistochemistry to perform a comprehensive expression profile of ErbB receptors and ligands in the mouse prostate. Physiological receptor activation in situ was measured by receptor phospho‐tyrosine analysis.RESULTSExpression of all four ErbB receptors and the EGF‐like ligands EGF, TGFα, AR, βC, Hb‐EGF, NRG1, and NRG3 was detected in the mouse prostate. We failed to detect expression of the ErbB ligand, ER. Physiological receptor activation was observed within the mature mouse prostate at 10 weeks but not in the prostates of 3‐ or 6‐week‐old mice.CONCLUSIONSCoordinated ErbB receptor and ligand expression coupled with receptor activation profiles provide strong evidence that ErbB signaling contributes to mouse prostate function. © 2004 Wiley‐Liss, Inc.
Decision‐rules for leaping Adélie penguins (Pygoscelis adeliae)
Authors: Yoda Ken , Ropert‐Coudert Yan 
Published: April 2004

AbstractAdélie penguins Pygoscelis adeliae were tested as to whether they jump with optimal energy efficiency when moving out of the sea to the land. Adélie penguins risk predation if the jump fails. Swimming penguins usually launch up the side of sea ice to a surface higher than sea level. Analysis of jumping behaviour recorded by a video camera showed that the trajectory of the centre of gravity of the birds during the aerial phase of jumping was parabolic, indicating that the success of landing depends on three parameters at the time of take‐off from water: speed, angle and distance from the point of emergence to the ice edge. There was a negative relationship between distance and the take‐off angle, suggesting that penguins adjust their take‐off angle to the distance from the ice edge. The comparison among hypotheses revealed that penguins did not jump with optimal energy efficiency. Instead, they aimed for the refracted image of the edge of the cliff, which from underwater appears higher than it actually is. This direction‐dependent rule seems to be more robust and reliable than the optimal energetic strategy.
High‐resolution computed tomography in healthy smokers and never‐smokers: a 6‐year follow‐up study of men born in 1933
Authors: Vikgren J. , Boijsen M. , Andelid K. , Ekberg‐Jansson A. , Larsson S. , Bake B. , TylÉn U. 
Published: April 2004

Purpose: To elucidate whether emphysematous lesions and other high‐resolution computed tomography (HRCT) findings considered associated with smoking are part of a progressive process, and to measure the extent to which similar changes are found in never‐smokers. Material and Methods: Healthy smokers and never‐smokers were recruited from a randomized epidemiological study and investigated with a 6‐year interval. Emphysema, parenchymal and subpleural nodules, ground‐glass opacities, bronchial alterations, and septal lines were evaluated in 66 subjects (40 smokers, 11 of whom had stopped smoking in the interval, and 26 never‐smokers). Lung function was tested. Results: All except emphysematous lesions were present to some extent in never‐smokers. Emphysema, parenchymal nodules, and septal lines occurred significantly more in current smokers, and a progression in extent of emphysema, ground‐glass opacities, bronchial alterations and septal lines was seen. There was no significant change among those who stopped and never‐smokers except for bronchial alterations, which progressed in never‐smokers. Conclusion: In healthy, elderly never‐smokers a low extent of various HRCT findings has to be considered normal. Emphysema, parenchymal nodules, and ground‐glass opacities are indicative of smoking‐induced disease. Further progress may cease if smoking is stopped.
Treatment of long superficial femoral artery occlusions with excimer laser angioplasty: long‐term results after 48 months
Authors: Wissgott C. , Scheinert D. , Rademaker J. , Werk M. , Schedel H. , Steinkamp H. J. 
Published: April 2004

Purpose: To evaluate clinical and hemodynamical long‐term results after laser angioplasty of long occlusions of the superficial femoral artery (SFA). Material and Methods: In a prospective trial of 452 patients with long occlusions of the SFA, excimer percutaneous transluminal laser angioplasty (PTLA) for recanalization was applied. The average occlusion length of the SFA was 25.5 cm (range 16–38 cm). The recanalization attempt was done with the crossover technique in 398 patients, in 36 patients with the antegrade technique and in another 18 patients with the transpopliteal technique. Results: The application of laser angioplasty demonstrated a successful recanalization of the SFA in 386/452 patients (85.5%). Recanalization with PTLA was not possible in 66 patients (14.5%). The main reason for the unsuccessful PTLAs was obstructing calcified material ( n=28) resistant to PTLA application. After a follow‐up period of 48 months there was a primary, primary‐assisted, and secondary patency rate of 22.3%, 40.9%, and 43.2%, respectively. Conclusion: Laser angioplasty of long occlusions of the SFA is a feasible procedure with a low failure rate. Long‐term results are promising, but additional interventions are required in most patients if a patency rate of 43.2% is to be achieved after 4 years.
Rapid‐sequence phosphorus‐31 magnetic resonance spectroscopy of the human heart using a 1.5‐T clinical system
Authors: Chida K. , Saito H. , Nagasaka T. , Otani H. , Kohzuki M. , Zuguchi M. 
Published: April 2004

Purpose: To compare a ‘standard’ slow phosphorus‐31 magnetic resonance spectroscopy (31P‐MRS) sequence with two faster sequences in phantoms and healthy volunteers using a 1.5‐T clinical system. Material and Methods: Complete 3D localization was performed using a 2D phosphorus chemical‐shift imaging sequence in combination with 30‐mm axial slice‐selective excitation. Two 31P‐MRS rapid sequences (RS8‐4: 8×8 phase‐encoding, with an average of 4 acquisitions, and RS16‐1: 16×16 phase‐encoding, 1 acquisition) were compared with the standard sequence (StdP: 16×16 phase‐encoding, with an average of 8 acquisitions) in phantom and healthy volunteers. Results: Acquisition time for the 31P‐MRS procedure with StdP, RS8‐4, and RS16‐1 in the healthy volunteer studies ranged from 30 to 45, 3 to 5, and 3 to 5 minutes, respectively. Metabolite measurements of healthy volunteers obtained from 31P‐MRS using RS8‐4 correlated with values obtained using StdP (PCr r2=0.63, P<0.001; ATP r2=0.41, P<0.01 and PCr/ATP ratio r2=0.25, P<0.05). There was no correlation between StdP and RS16‐1 for either ATP or the PCr/ATP ratio ( r2=0.03, P=0.60, and r2=0.11, p=0.26, respectively). Reproducibility (intensity of phosphorus signal) with RS16‐1 was worse than that of RS8‐4 or StdP. Conclusion:31P‐MRS using RS8‐4 may be a valid diagnostic tool for patients with cardiac diseases.
Pelvic imaging: multicystic uterine cervical lesions. can magnetic resonance imaging differentiate benignancy from malignancy?
Authors: Okamoto Y. , Tanaka Y. O. , Nishida M. , Tsunoda H. , Yoshikawa H. 
Published: April 2004

Purpose: To evaluate whether magnetic resonance imaging (MRI) can be used to differentiate between malignant and benign multicystic uterine cervical lesions. Material and Methods: Twenty‐two patients with cervical adenocarcinomas, including minimal deviation adenocarcinoma, and five patients with benign multicystic lesions were classified as a percentage of solid components on MRI. Cystic components were further classified by average cyst diameter and signal intensity of the cyst fluid on T1WI. Results: All nine of the entirely solid lesions were malignant. In contrast, two of the entirely cystic lesions were benign. Ten of the ordinary adenocarcinomas had both solid and cystic components. However, three of the 16 solid and cystic lesions were benign. Lesions composed of cysts smaller than 5 mm tended to be malignant; however, some lesions composed of larger cysts were also malignant. Three of 5 lesions with low‐signal and 7 of 10 with intermediate‐signal fluid were malignant. Conclusion: The malignancy potential was higher in the lesions with a higher percentage of solid components. However, determining whether multicystic lesions were benign or malignant based on the existence of solid components, the average cyst size, and the signal intensity of cyst fluid was impossible. Although a multicystic lesion with solid components in the deep cervical stroma had been reported as a MR finding of a minimal deviation adenocarcinoma, this does not appear to be pathognomonic.