julilili42/papers huggingface dataset:
A link between sterol biosynthesis, the cell wall, and cellulose in Arabidopsis
2004-03-01

Summary A crucial role for sterols in plant growth and development is underscored by the identification of three Arabidopsis sterol biosynthesis mutants that exhibit embryonic defects: fackel ( fk ), hydra1 ( hyd1 ), and sterol methyltransferase 1/cephalopod ( smt1/cph ). We have taken a dual approach of sterol profiling and ultrastructural analysis to investigate the primary defects underlying the mutant phenotypes. Comprehensive gas chromatography (GC)–MS analysis of hyd1 in comparison to fk reveals an abnormal accumulation of unique sterol intermediates in each case. Sterol profiling of the fk hyd1 double mutant provides genetic evidence that FK C‐14 reductase acts upstream of HYD1 C‐8,7 isomerase. Despite distinct differences in sterol profiles, fk and hyd1 as well as smt1/cph share ultrastructural features such as incomplete cell walls and aberrant cell wall thickenings in embryonic and post‐embryonic tissues. The common defects are coupled with ectopic callose and lignin deposits. We show that all three mutants exhibit a deficiency in cellulose, but are not reduced in pectin and sugars of the cell wall and cytosol. The sterol biosynthesis inhibitors 15‐azasterol and fenpropimorph also cause cell wall gaps in dividing root cells and a reduction in bulk cellulose, corroborating that the cell wall abnormalities are due to altered sterol composition. Our results demonstrate that sterols are crucial for cellulose synthesis in the building of the plant cell wall.
Vaccination of Patients with Advanced Ovarian Carcinoma with the Anti-Idiotype ACA125
2004-03-01

Abstract Purpose: A Phase I/IIb multicenter study was conducted to evaluate the safety and immunogenicity of the anti-idiotypic antibody vaccine ACA125 that functionally imitates the tumor antigen CA125 in 119 patients with advanced ovarian carcinoma. A preliminary report on the initial 42 patients demonstrated safety and immunogenicity. Experimental Design: Using the complete intention-to-treat population (n = 119) who received a mean of 9.7 ACA125 applications, survival was analyzed with respect to immunological responses. Results: In 81 patients (68.1%), a specific anti-anti-idiotypic antibody (Ab3) response could be induced. Additionally, the development of CA125-specific antibodies (Ab1′) and antibody-dependent cell-mediated cytotoxicity of CA125-positive tumor cells was observed in 50.4% and 26.9% of patients, respectively. The median survival of all patients was 19.4 months (range, 0.5–56.1 months). Ab3-positive patients showed a significantly longer survival (median, 23.4 months; P &amp;lt; 0.0001) as compared with Ab3-negative patients (median, 4.9 months). A positive Ab3 response remained associated with longer survival when controlling for other prognostic factors including FIGO (International Federation of Gynecologists and Obstetricians) stage, response to and type of first-line chemotherapy, number of previous treatments, or concomitant antitumor therapy. With regard to safety, repeated vaccination was well tolerated. No serious adverse events related to the application of ACA125 occurred. Conclusions: Although the uncontrolled design of this study prevents definitive conclusions with respect to subgroups, the data support a relationship between Ab3 response and survival time. Thus, the need for further randomized, controlled clinical trials to establish efficacy of the vaccine ACA125 seems to be indicated.
Temporal Organization of “Internal Speech” As a Basis for Cerebellar Modulation of Cognitive Functions
2004-03-01

The sequencing of smooth and rhythmically “sculptured” words and phrases at a speaker’s habitual speech rate (4 Hz to 6 Hz) critically depends on the cerebellum. Besides overt performance, the cerebellum also seems to organize the syllabic structure of “auditory verbal imagery” or “internal speech”—that is, a prearticulatory but otherwise fully elaborated and temporally organized representation of verbal utterances. As a consequence, cerebellar disorders may compromise cognitive operations that involve a speech code, such as verbal working memory, or disrupt cognitive processes that encompass linguistic mediation. Besides the temporal organization of syllable strings at a prearticulatory level, cerebellar patients are impaired in speech perception tasks requiring the encoding of durational parameters of the acoustic signal. The hemodynamic responses associated with these two aspects of verbal-acoustic communication— internal speech and speech perception—were found to be organized along the rostro-caudal direction within paravermal aspects of the superior right cerebellar hemisphere. Those areas of the right cerebellar hemisphere thus might provide a common platform for the computation of temporal aspects of verbal utterances in the domains of both speech production and perception.
Large mesh simplification using processing sequences
2004-03-01

In this paper we show how out-of-core mesh processing techniques can be adapted to perform their computations based on the new processing sequence paradigm (Isenburg, et al., 2003), using mesh simplification as an example. We believe that this processing concept will also prove useful for other tasks, such a parameterization, remeshing, or smoothing, for which currently only in-core solutions exist. A processing sequence represents a mesh as a particular interleaved ordering of indexed triangles and vertices. This representation allows streaming very large meshes through main memory while maintaining information about the visitation status of edges and vertices. At any time, only a small portion of the mesh is kept in-core, with the bulk of the mesh data residing on disk. Mesh access is restricted to a fixed traversal order, but full connectivity and geometry information is available for the active elements of the traversal. This provides seamless and highly efficient out-of-core access to very large meshes for algorithms that can adapt their computations to this fixed ordering. The two abstractions that are naturally supported by this representation are boundary-based and buffer-based processing. We illustrate both abstractions by adapting two different simplification methods to perform their computation using a prototype of our mesh processing sequence API. Both algorithms benefit from using processing sequences in terms of improved quality, more efficient execution, and smaller memory footprints.
Senescence‐Related Gene Expression Profiles of Rosette Leaves of Arabidopsis thaliana: Leaf Age Versus Plant Age
2004-03-01

Abstract: Senescence is a form of programmed cell death (PCD) which leads to the death of whole organs, e.g., leaves or flowers, and eventually to the death of entire plants. Like all forms of PCD, senescence is a highly regulated and energy consuming process. Senescence parameters, like protein content, chlorophyll content, expression of photosynthesis‐associated genes or senescence‐associated genes (SAGs), reveal that senescence occurs in old leaves derived from young plants (6 week old) as well as in young leaves derived from older plants (8 week old), indicating that it is governed by the actual age of the leaves. In order to analyse the differential gene expression profiles during leaf senescence, hybridizations of high‐density genome arrays were performed with: i) individual leaves within the rosette of a 6‐week‐old plant and ii) leaves of the same position within the rosette but harvested from plants of different ages, ranging from 5 to 8 weeks. Cluster and genetree analyses, according to the expression pattern revealed that genes which are up‐regulated with respect to the age of the entire plant, showed completely different expression profiles with respect to the age of the individual leaves within one rosette. This was observed even though the actual difference in leaf age was approximately the same. This indicates that gene expression appears to be governed by different parameters: i) the age of the individual leaf and ii) the age and developmental stage of the entire plant.
Inhibition of Epidermal Growth Factor Receptor Signaling Protects Human Malignant Glioma Cells from Hypoxia-Induced Cell Death
2004-03-01

Abstract Epidermal growth factor receptor (EGFR) signaling has become an important target for drug development because EGFR signaling enhances tumor cell proliferation, migration, and invasion and inhibits apoptosis. However, the results of clinical trials using EGFR inhibitors in patients with solid tumors have been disappointing. Here, we report a protective effect of the EGFR inhibitors AG1478 and PD153035 against cell death induced by acute hypoxia, which contrasts with their proapoptotic effects under normoxia. Under hypoxic conditions, both agents reduced glucose consumption, delayed ATP depletion, and preserved the mitochondrial membrane potential. Exposure either to hypoxia or the EGFR inhibitors under normoxic conditions resulted in the dephosphorylation of ribosomal protein S6, a player in the energy and nutrient-sensing pathway governed by mammalian target-of-rapamycin (mTOR). Combined inhibition of phosphatidylinositol 3′-kinase (PI3K) and extracellular signal-regulated kinase-1/2 (ERK1/2) mimicked the protective effects of EGFR inhibition on hypoxia-induced cell death and protein S6 dephosphorylation. These results caution that therapies targeting EGFR signaling pathways can protect tumor cells from acute hypoxia.
Characterization of a Chiral Stationary Phase by HR/MAS NMR Spectroscopy and Investigation of Enantioselective Interaction with Chiral Ligates by Transferred NOE
2004-03-01

The surface chemistry of a chiral stationary phase (CSP) with a (tert-butyl carbamoyl) quinine selector immobilized on thiol-modified silica has been characterized by (1)H HR/MAS NMR and (29)Si CP/MAS NMR spectroscopy. The mostly well-resolved (1)H signals could be assigned to stem from the surface-bound selector and the latter suggested a bi- and trifunctional silane linkage. Suspended-state NMR spectroscopy thus proved a well-characterized surface chemistry as proposed. To study chiral recognition phenomena in the presence of the CSP, (1)H HR/MAS 2D transfer NOESY investigations in methanol-d(4) have been undertaken with various solutes including N-3,5-dinitrobenzoyl derivatives of leucine (DNB-Leu) and N-acetyl phenylalanine (Ac-Phe). Both (R)- and (S)-enantiomers of DNB-Leu and Ac-Phe interacted with the tBuCQN-CSP as indicated by negative cross-peaks in the trNOESY spectra, while the 2D NOESY of the dissolved solutes in absence of the chiral stationary phase showed positive cross-peaks. The intensities of the trNOE cross-peaks were much stronger for the (S)-enantiomers. This stereoselectivity paralleled the experimental chromatographic behavior, where the (S)-enantiomers revealed stronger binding and retention on the tBuCQN-CSP as well. Hence, we were able to correlate the retention behavior to the trNOE NMR spectroscopic data in a qualitative manner.
Hybrid segmentation and exploration of the human lungs
2004-03-01

Segmentation of the tracheo-bronchial tree of the lungs is notoriously difficult. This is due to the fact that the small size of some of the anatomical structures is subject to partial volume effects. Furthermore, the limited intensity contrast between the participating materials (air, blood, and tissue) increases the segmentation of difficulties. In this paper, we propose a hybrid segmentation method which is based on a pipeline of three segmentation stages to extract the lower airways down to the seventh generation of the bronchi. User interaction is limited to the specification of a seed point inside the easily detectable trachea at the upper end of the lower airways. Similarly, the complementary vascular tree of the lungs can be segmented. Furthermore, we modified our virtual endoscopy system to visualize the vascular and airway system of the lungs along with other features, such as lung tumors.
Trinucleotide repeat expansion in SCA17/TBP in white patients with Huntington’s disease-like phenotype
2004-03-01

<i>Purpose:</i>To determine if urinary symptoms are more common in women during the 4 weeks after a routine pelvic examination. <i>Methods:</i>This was a 4-week, prospective, observational cohort study in a Family Medicine residency clinic at an urban university. Participants included women ages 18 to 40 years who identified themselves as sexually active and who presented for a routine pelvic examination. Controls were women presenting for other health maintenance with no pelvic examination. Independent variables included age, pelvic examination/no pelvic examination, intercourse frequency, and condom use. Dependent variables included dysuria and urinary frequency. Relative rates of dysuria and frequency were compared using χ<sup>2</sup> analysis. Mean rates of dysuria, frequency, intercourse, and condom use were compared using 2-tailed <i>t</i> tests. <i>Results:</i>Sixty-three subjects and 87 controls completed the study. More subjects had days with dysuria (17% vs 7%; <i>P</i> &lt; .01), days with frequency (27% vs 14%; <i>P</i> &lt; .01), days with both dysuria and frequency (13% vs 3%; <i>P</i> &lt; .01), and days with either dysuria or frequency (32% vs 17%; <i>P</i> &lt; .01). Subjects had less intercourse than controls (1.6 times per week vs 2.2 times per week; <i>P</i> &lt; .01) and used condoms less frequently (33% vs 41%; <i>P</i> &lt; .01). <i>Conclusions:</i>Dysuria and urinary frequency are more common among sexually active women during the month after a routine pelvic examination.
Phakometric measurement of ocular surface radii of curvature, axial separations and alignment in relaxed and accommodated human eyes
2004-03-01

Abstract Measurements (autokeratometry, A‐scan ultrasonography and video ophthalmophakometry) of ocular surface radii, axial separations and alignment were made in the horizontal meridian of nine emmetropes (aged 20–38 years) with relaxed (cycloplegia) and active accommodation (mean ± 95% confidence interval: 3.7 ± 1.1 D). The anterior chamber depth (−1.5 ± 0.3 D) and both crystalline lens surfaces (front 3.1 ± 0.8 D; rear 2.1 ± 0.6 D) contributed to dioptric vergence changes that accompany accommodation. Accommodation did not alter ocular surface alignment. Ocular misalignment in relaxed eyes is mainly because of eye rotation (5.7 ± 1.6° temporally) with small amounts of lens tilt (0.2 ± 0.8° temporally) and decentration (0.1 ± 0.1 mm nasally) but these results must be viewed with caution as we did not account for corneal asymmetry. Comparison of calculated and empirically derived coefficients (upon which ocular surface alignment calculations depend) revealed that negligible inherent errors arose from neglect of ocular surface asphericity, lens gradient refractive index properties, surface astigmatism, effects of pupil size and centration, assumed eye rotation axis position and use of linear equations for analysing Purkinje image shifts.
Ease of imagination moderates reactions to differently framed health messages
2004-03-01

Abstract Three studies test the hypothesis that the subjective ease of symptom imagination moderates the impact of differently framed messages on attitudes toward performing health behaviours. By drawing on the simulation heuristic, it is argued that the vividness of information is reflected in the subjective ease with which people can imagine having symptoms of an illness. This state of mind can be more or less congruent with the theme of a message, accentuating certain health‐related outcomes more than others. The results show that negatively framed messages are more persuasive when symptom imagination is relatively easy and that positively framed messages are more effective when symptom imagination is relatively difficult. Consistent with a dual‐process view, Study 3 showed a stronger impact of ease of imagination when relevance was low rather than high. Copyright © 2004 John Wiley &amp; Sons, Ltd.
Population dynamics of galeate acritarchs at the Cambrian–Ordovician transition in the Algerian Sahara
2004-03-01

Galeate acritarchs are a major component of Late Cambrian and Early Ordovician palynological assemblages. The populations of galeate acritarchs from the Cambrian–Ordovician transition section in borehole Nl‐2 of the Algerian Sahara show a gradual increase in process length and in complexity of the process structures through the succession. While the number of striate elements at the process base, the number of distal ramifications, and the number of membranes between the processes increases progressively, the central body diameter shows only minor variation within the succession. The galeate acritarchs are here interpreted as probably being resting cysts of a microorganism similar to modern dinoflagellates. Published laboratory culture experiments on living dinoflagellates document a considerable morphological variation with respect to the process morphology of the resting cysts that can be produced by a single biologically defined species. Based on these experiments, it is possible to interpret the morphological changes in the galeate acritarchs as being possibly related to changing ecological conditions. By analogy to the cyst distribution of modern dinoflagellates, changing salinity may have played an important role. Depending on environmental parameters, and perhaps on the maturity attained before rupture of the outer membrane during cyst formation, the galeate acritarchs may show a wide variety of process morphologies that have to date been used to describe four genera (morphogenera) and 84 species (morphospecies).
Analysis of Autoreactive CD4 T Cells in Experimental Autoimmune Encephalomyelitis after Primary and Secondary Challenge Using MHC Class II Tetramers
2004-03-01

Abstract Experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, is primarily mediated by CD4 T cells specific for Ags in the CNS. Using MHC class II tetramers, we assessed expansion and phenotypic differentiation of polyclonal self-reactive CD4 T cells during EAE after primary and secondary challenge with the specific Ag. After EAE induction in SJL mice with proteolipid protein 139–151, CNS-specific T cells up-regulated activation markers and expanded in the draining lymph nodes and in the spleen. Less than 20% of total autoreactive T cells entered the CNS simultaneously with Th cells of other specificities. Almost all tetramer-positive cells in the CNS were activated and phenotypically distinct from the large peripheral pool. When EAE was induced in Ag-experienced mice, disease symptoms developed earlier and persisted longer; autoreactive T cells were more rapidly activated and invaded the CNS earlier. In striking contrast to specific CTLs that respond after secondary viral challenge, the absolute numbers of autoreactive CD4 T cells were not increased, indicating that the accelerated autoreactivity in Ag-experienced mice is not related to higher frequencies of autoreactive CD4 T cells.
Effects of brain‐derived neurotrophic factor on cell survival, differentiation and patterning of neuronal connections and Müller glia cells in the developing retina
2004-03-01

Abstract The aim of the present study was to determine the influence of brain‐derived neurotrophic factor (BDNF) on survival, phenotype differentiation and network formation of retinal neurons and glia cells. To achieve a defined concentration and constant level of BDNF over several days, experiments were performed in an organotypic culture of the developing rat retina. After 6 days in vitro , apoptosis in the different cell layers was determined by TUNEL staining and cell‐type‐specific antibodies were used to identify distinct neuronal cell types and Müller cells. Cultured retinas treated with BDNF (100 ng BDNF/mL medium) were compared with untreated as well as with age‐matched in vivo retinas. Quantitative morphometry was carried out using confocal microscopy. BDNF promoted the in vitro development and differentiation of the retina in general, i.e. the number of cells in the nuclear layers and the thickness of the plexiform layers were increased. For all neurons, the number of cells and the complexity of arborizations in the synaptic layers were clearly up‐regulated by BDNF. In control cultures, the synaptic stratification of cone bipolar cells within the On‐ and Off‐layer of the inner plexiform layer was disturbed and a strong reactivity of Müller cell glia was observed. These effects were not present in BDNF‐treated cultures. Our data show that BDNF promotes the survival of retinal interneurons and plays an important role in establishing the phenotypes and the synaptic connections of a large number of neuronal types in the developing retina. Moreover, we show an effect of BDNF on Müller glia cells.
Documentation of 7051 Chronic Wounds Using a New Computerized System Within a Network of Wound Care Centers
2004-03-01

The German Wound Net achieved, for the first time, centralized and prospective documentation of more than 7000 chronic wounds treated according to defined guidelines. This new concept of a network of specialized wound care centers working with standardized treatment plans and prospective documentation of chronic wounds may open a new dimension for wound-healing studies and may represent an optimal platform for multicenter trials.
Corrosion penetration monitoring of advanced ceramics in hot aqueous fluids
2004-03-01

Advanced ceramics are considered as components in energy related systems, because they are known to be strong, wear and corrosion resistant in many environments, even at temperatures well exceeding 1000 °C. However, the presence of additives or impurities in important ceramics, for example those based on Silicon Nitride (Si3N4) or Al2O3 makes them vulnerable to the corrosion by hot aqueous fluids. The temperatures in this type of corrosion range from several tens of centigrade to hydrothermal conditions above 100 °C. The corrosion processes in such media depend on both pH and temperature and include often partial leaching of the ceramics, which cannot be monitored easily by classical gravimetric or electrochemical methods. Successful corrosion penetration depth monitoring by polarized reflected light optical microscopy (color changes), Micro Raman Spectroscopy (luminescence changes) and SEM (porosity changes) will be outlined. The corrosion process and its kinetics are monitored best by microanalysis of cross sections, Raman spectroscopy and eluate chemistry changes in addition to mass changes. Direct cross-calibrations between corrosion penetration and mechanical strength is only possible for severe corrosion. The methods outlined should be applicable to any ceramics corrosion process with partial leaching by fluids, melts or slags.
Multiple Symmetric Lipomatosis
2004-03-01

Excessive fat storage (obesity) is associated with insulin resistance and type 2 diabetes (1). Paradoxically, inability to store fat (lipodystrophy) is also associated with insulin resistance (2). In both obesity and lipodystrophy, the adipocyte’s storage capacity is exceeded and lipids accumulate in liver, muscle, and β-cells. Hypothetically, if adipose tissue had an intrinsic propensity to proliferate, rather than passively respond to energy excess, calories should be extracted from the circulation and the system should become (or remain) insulin sensitive. Such a process would be particularly effective if it occurred preferentially in subcutaneous adipose tissue, which, metabolically, is the least harmful site (3). We performed extensive metabolic studies in two patients (Table 1) with multiple symmetric lipomatosis (MSL), a condition characterized by regional excess of subcutaneous adipose tissue (4). Patient 1 had massive symmetrical subcutaneous fat accumulation in the thoracic, abdominal, and upper arm region (Fig. 1 A ) that had begun to develop about 15 years earlier. Patient ...