julilili42/papers huggingface dataset:
Nonradial oscillations of slowly and differentially rotating compact stars
2007-03-16

The equations describing nonradial adiabatic oscillations of differentially rotating relativistic stars are derived in relativistic slow rotation approximation. The differentially rotating configuration is described by a perturbative version of the relativistic j-constant rotation law. Focusing on the oscillation properties of the stellar fluid, the adiabatic nonradial perturbations are studied in the Cowling approximation with a system of five partial differential equations. In these equations, differential rotation introduces new coupling terms between the perturbative quantities with respect to the uniformly rotating stars. In particular, we investigate the axisymmetric and barotropic oscillations and compare their spectral properties with those obtained in nonlinear hydrodynamical studies. The perturbative description of the differentially rotating background and the oscillation spectrum agree within a few percent with those of the nonlinear studies.
EAAT4 phosphorylation at the SGK1 consensus site is required for transport modulation by the kinase
2007-03-16

Abstract EAAT4 (SLC1A6) is a Purkinje‐Cell‐specific post‐synaptic excitatory amino acid transporter that plays a major role in clearing synaptic glutamate. EAAT4 abundance and function is known to be modulated by the serum and glucocorticoid inducible kinase (SGK) 1 but the precise mechanism of kinase action has not been defined yet. The present work aims to identify the molecular mechanism of EAAT4 modulation by the kinase. The EAAT4 sequence bears two putative SGK1 consensus sites (at Thr40 and Thr504) at the amino and carboxy terminus that are conserved among species. Expression studies in Xenopus oocytes demonstrated that EAAT4‐mediated [ 3 H] glutamate uptake and cell surface abundance are enhanced by co‐expression of SGK1. Disruption of the SGK1 phosphorylation site at threonine 40 ( T40A EAAT4) or of both phosphorylation sites ( T40AT504A EAAT4) abrogated the effect of SGK1 on transporter function and expression. SGK1 modulates several transport proteins via inhibition of the ubiquitin ligase Nedd4‐2. Co‐expression of Nedd4‐2 inhibited wild‐type EAAT4 but not the T40AT504A EAAT4 mutant. Besides, RNA interference‐mediated reduction of endogenous Nedd4‐2 (xNedd4‐2) expression increased the activity of the transporter. In conclusion, maximal glutamate transport modulation by SGK1 is accomplished by direct EAAT4 stimulation and to a lesser extent by inhibition of intrinsic Nedd4‐2.
Localization of cadmium in the root cells of Allium cepa by energy dispersive x-ray analysis
2007-03-19

Allium cepa L. roots were exposed to 0.1 and 1.0 mM Cd for 6, 24 and 48 h and the localization of Cd in the root tissue was investigated. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) were performed on frozen-dried tissues of roots. No Cd was detected in the roots treated with only 0.1 mM Cd, while after exposure to higher Cd concentration (1.0 mM) Cd was observed in cell wall and in cytoplasm in the epidermis, cortex and vascular tissues in the roots.
Identification of SOX2 as a novel glioma-associated antigen and potential target for T cell-based immunotherapy
2007-03-20

Prognosis for patients suffering from malignant glioma has not substantially improved. Specific immunotherapy as a novel treatment concept critically depends on target antigens, which are highly overexpressed in the majority of gliomas, but the number of such antigens is still very limited. SOX2 was identified by screening an expression database for transcripts that are overexpressed in malignant glioma, but display minimal expression in normal tissues. Expression of SOX2 mRNA was further investigated in tumour and normal tissues by real-time PCR. Compared to cDNA from pooled normal brain, SOX2 was overexpressed in almost all (9 out of 10) malignant glioma samples, whereas expression in other, non-malignant tissues was almost negligible. SOX2 protein expression in glioma cell lines and tumour tissues was verified by Western blot and immunofluorescence. Immunohistochemistry demonstrated SOX2 protein expression in all malignant glioma tissues investigated ranging from 6 to 66% stained tumour cells. Human leucocyte antigen-A(*)0201-restricted SOX2-derived peptides were tested for the activation of glioma-reactive CD8+ cytotoxic T lymphocytes (CTLs). Specific CTLs were raised against the peptide TLMKKDKYTL and were capable of lysing glioma cells. The abundant and glioma-restricted overexpression of SOX2 and the generation of SOX2-specific and tumour-reactive CTLs may recommend this antigen as target for T-cell-based immunotherapy of glioma.
HLA-G expression defines a novel regulatory T-cell subset present in human peripheral blood and sites of inflammation
2007-03-20

Abstract Regulatory T cells can inhibit harmful immunopathologic responses directed against self and foreign antigens and play a major role in controlling autoimmunity. Here we have identified and characterized a subpopulation of CD4 and CD8 T cells in human peripheral blood expressing the immune tolerizing molecule HLA-G. HLA-G–expressing T cells are hypoproliferative, are CD25- and FOXP3-negative, and exhibit potent suppressive properties that are partially mediated by HLA-G. HLA-G–positive (HLA-Gpos) T cells are found at low percentages among CD4 and CD8 single-positive thymocytes, suggesting a thymic origin. The presence of HLA-Gpos T cells at sites of inflammation such as inflamed skeletal muscle in myositis or the cerebrospinal fluid of patients with acute neuroinflammatory disorders suggests an important function in modulating parenchymal inflammatory responses in vivo.
A unifying new model of cytokinesis for the dividing plant and animal cells
2007-03-20

Abstract Cytokinesis ensures proper partitioning of the nucleocytoplasmic contents into two daughter cells. It has generally been thought that cytokinesis is accomplished differently in animals and plants because of the differences in the preparatory phases, into the centrosomal or acentrosomal nature of the process, the presence or absence of rigid cell walls, and on the basis of ‘outside‐in’ or ‘inside‐out’ mechanism. However, this long‐standing paradigm needs further reevaluation based on new findings. Recent advances reveal that plant cells, similarly to animal cells, possess astral microtubules that regulate the cell division plane. Furthermore, endocytosis has been found to be important for cytokinesis in animal and plant cells: vesicles containing endocytosed cargo provide material for the cell plate formation in plants and for closure of the midbody channel in animals. Thus, although the preparatory phases of the cell division process differ between plant and animal cells, the later phases show similarities. We unify these findings in a model that suggests a conserved mode of cytokinesis. BioEssays 29:371–381, 2007. © 2007 Wiley Periodicals, Inc.
The AtGenExpress global stress expression data set: protocols, evaluation and model data analysis of UV‐B light, drought and cold stress responses
2007-03-21

Summary The tolerance responses of plants to many abiotic stresses are conjectured to be controlled by complex gene networks. In the frame of the AtGenExpress project a comprehensive Arabidopsis thaliana genome transcript expression study was performed using the Affymetrix ATH1 microarray in order to understand these regulatory networks in detail. In contrast to earlier studies, we subjected, side‐by‐side and in a high‐resolution kinetic series, Arabidopsis plants, of identical genotype grown under identical conditions, to different environmental stresses comprising heat, cold, drought, salt, high osmolarity, UV‐B light and wounding. Furthermore, the harvesting of tissue and RNA isolation were performed in parallel at the same location using identical experimental protocols. Here we describe the technical performance of the experiments. We also present a general overview of environmental abiotic stress‐induced gene expression patterns and the results of a model bioinformatics analysis of gene expression in response to UV‐B light, drought and cold stress. Our results suggest that the initial transcriptional stress reaction of Arabidopsis might comprise a set of core environmental stress response genes which, by adjustment of the energy balance, could have a crucial function in various stress responses. In addition, there are indications that systemic signals generated by the tissue exposed to stress play a major role in the coordination and execution of stress responses. In summary, the information reported provides a prime reference point and source for the subsequent exploitation of this important resource for research into plant abiotic stress.
Function of the anion transporter AtCLC‐d in the trans‐Golgi network
2007-03-21

Summary Anion transporting proteins of the CLC type are involved in anion homeostasis in a variety of organisms. CLCs from Arabidopsis have been shown to participate in nitrate accumulation and storage. In this study, the physiological role of the functional chloride transporter AtCLC‐d from Arabidopsis was investigated. AtCLC‐d is weakly expressed in various tissues, including the root. When transiently expressed as a GFP fusion in protoplasts, it co‐localized with the VHA‐a1 subunit of the proton‐transporting V‐type ATPase in the trans ‐Golgi network (TGN). Stable expression in plants showed that it co‐localized with the endocytic tracer dye FM4‐64 in a brefeldin A‐sensitive compartment. Immunogold electron microscopy confirmed the localization of AtCLC‐d to the TGN. Disruption of the AtCLC‐d gene by a T‐DNA insertion did not affect the nitrate and chloride contents. The overall morphology of these clcd‐1 plants was similar to that of the wild‐type, but root growth on synthetic medium was impaired. Moreover, the sensitivity of hypocotyl elongation to treatment with concanamycin A, a blocker of the V‐ATPase, was stronger in the clcd‐1 mutant. These phenotypes could be complemented by overexpression of AtCLC‐d in the mutant background. The results suggest that the luminal pH in the trans ‐Golgi network is adjusted by AtCLC‐d‐mediated transport of a counter anion such as Cl − or NO 3 − .
Role of persistent CMV infection in configuring T cell immunity in the elderly
2007-03-21

Ageing is associated with declines in many physiological parameters, including multiple immune system functions. The rate of acceleration of the frequency of death due to cardiovascular disease or cancer seems to increase with age from middle age up to around 80 years, plateauing thereafter. Mortality due to infectious disease, however, does not plateau, but continues to accelerate indefinitely. The elderly commonly possess oligoclonal expansions of T cells, especially of CD8 cells, which, surprisingly, are often associated with cytomegalovirus (CMV) seropositivity. This in turn is associated with many of the same phenotypic and functional alterations to T cell immunity that have been suggested as biomarkers of immune system aging. Thus, the manner in which CMV and the host immune system interact is critical in determining the "age" of specific immunity. We may therefore consider immunosenescence in some respects as an infectious state. This implies that interventions aimed at the pathogen may improve the organ system affected. Hence, CMV-directed anti-virals or vaccination may have beneficial effects on immunity in later life.
Thyroid Hormone Deficiency Affects Postnatal Spiking Activity and Expression of Ca2+and K+Channels in Rodent Inner Hair Cells
2007-03-21

Thyroid hormone (TH) is essential for the development of hearing. Lack of TH in a critical developmental period from embryonic day 17 to postnatal day 12 (P12) in rats and mice leads to morphological and functional deficits in the organ of Corti and the auditory pathway. We investigated the effects of TH on inner hair cells (IHCs) using patch-clamp recordings, capacitance measurements, and immunocytochemistry in hypothyroid rats and athyroid Pax8 −/− mice. Spontaneous and evoked Ca 2+ action potentials (APs) were present in control IHCs from P3–P11 rats and vanished in parallel with the expression of a rapidly activating Ca 2+ - and voltage-activated K + (BK) conductance. IHCs of hypothyroid rats and athyroid Pax8 −/− mice displayed APs until the end of the third postnatal week because of threefold elevated Ca 2+ currents and missing expression of BK currents. After the fourth postnatal week, some IHCs showed BK currents whereas adjacent IHCs did not, demonstrated by electrophysiology and immunocytochemistry. To test whether the prolonged spiking activity during TH deficiency may be transmitted at IHC synapses, capacitance measurements were performed in parallel to analysis of otoferlin expression, a protein thought to play an essential role in exocytosis of IHCs. Strikingly, otoferlin was absent from IHCs of hypothyroid rats but not of Pax8 −/− mice, although both cell types showed exocytosis with an efficiency typical for immature IHCs. These results demonstrate for the first time a TH-dependent control of IHC spiking activity before the onset of hearing attributable to effects of TH on Ca 2+ and BK channels. Moreover, they question an indispensable role of otoferlin for exocytosis in IHCs.
Molecular mechanisms of ammonium transport and accumulation in plants
2007-03-22

The integral membrane proteins of the ammonium transporter (AMT/Rh) family provide the major route for shuttling ammonium urn:x-wiley:00145793:media:feb2s0014579307003006:feb2s0014579307003006-math-0002 across bacterial, archaeal, fungal and plant membranes. These proteins are distantly related to the Rh (rhesus) glycoproteins, which are absent in higher plants, but are present in many species, including bacteria and mammals. It appears that the large nitrogen requirement of plants resulted in unique strategies to acquire, capture and/or release ammonium. The biological function of plant ammonium transporters will be discussed and compared to other AMT/Rh proteins.
2,2-Dimethyl-N-[3-(3,4,5-trimethoxybenzoyl)pyridin-4-yl]propanamide
2007-03-22

The title compound, C20H24N2O5, was found to have an intramolecular N—H⋯O bond with an N⋯O distance of 2.646 (2) Å. In the crystal structure, molecules form dimers along the c axis by aromatic stacking interactions. The X-ray crystallographic analysis was carried out to correlate the solid-state geometry with virtual structural information obtained by modelling.
Platelets Recruit Human Dendritic Cells Via Mac-1/JAM-C Interaction and Modulate Dendritic Cell Function In Vitro
2007-03-23

Objective— Thrombotic events and immunoinflammatory processes take place next to each other during vascular remodeling in atherosclerotic lesions. In this study we investigated the interaction of platelets with dendritic cells (DCs). Methods and Results— The rolling of DCs on platelets was mediated by PSGL-1. Firm adhesion of DCs was mediated through integrin α M β 2 (Mac-1). In vivo, adhesion of DCs to injured carotid arteries in mice was mediated by platelets. Pretreatment with soluble GPVI, which inhibits platelet adhesion to collagen, substantially reduced recruitment of DCs to the injured vessel wall. In addition, preincubation of DCs with sJAM-C significantly reduced their adhesion to platelets. Coincubation of DCs with platelets induced maturation of DCs, as shown by enhanced expression of CD83. In the presence of platelets, DC-induced lymphocyte proliferation was significantly enhanced. Moreover, coincubation of DCs with platelets resulted in platelet phagocytosis by DCs, as verified by different cell phagocytosis assays. Finally, platelet/DC interaction resulted in apoptosis of DCs mediated by a JAM-C–dependent mechanism. Conclusions— Recruitment of DCs by platelets, which is mediated via CD11b/CD18 (Mac-1) and platelet JAM-C, leads to DC activation and platelet phagocytosis. This process may be of importance for progression of atherosclerotic lesions.
Environmental Factors Influencing Sorption of Heterocyclic Aromatic Compounds to Soil
2007-03-23

Heterocyclic organic compounds containing nitrogen, sulfur, or oxygen (NSOs) are an important class of groundwater contaminants related to the production and use of manufactured gas, heavy oils, and coal tar. Surprisingly little is known about the processes that control sorption and transport of NSOs in the subsurface. In this study, the effects of various environmental factors including temperature, ionic strength, and dissolved/sorbed ion composition on the sorption of NSOs have been investigated by means of a soil column chromatography approach. For the investigated compounds, increased temperature normally decreases their sorption to soil. The enthalpy change of the sorption process corroborates earlier findings that van der Waals forces dominate the sorption of S- and O-heterocyclic compounds such as thiophene, benzothiophene, benzofuran, and 2-methylbenzofuran. Ionic strength and ion composition (Ca2+ vs K+ at given ionic strength) of the aqueous phase show no significant effects on the sorption of these compounds. Previous studies demonstrated that for N-heterocyclic compounds, cation exchange and surface complex formation rather than partitioning into soil organic matter control their overall sorption. In contrast to S- and O-heterocyclic compounds, increasing ionic strength reduced the sorption of ionizable N-heterocyclic compounds (pyridine, 2-methylpyridine, quinoline, 2-methylquinoline, and isoquinoline), due to increased electrostatic competition by cations. At given ionic strength, an increase of the K+/Ca2+ ratio in the mobile phase enhanced the sorption of N-heterocyclic compounds, consistent with cation exchange of the protonated organic species as the dominating sorption process. Among the investigated N-heterocyclic compounds sorption of benzotriazole showed a peculiar feature in that ternary surface complexation with Ca2+ appears to be the dominant sorption mechanism.
Enantioselective Total Synthesis of (+)-Neosymbioimine
2007-03-23

[reaction: see text] The enantioselective total synthesis of (+)-neosymbioimine was accomplished in 18 steps from (-)-(S)-citronellol utilizing an organocatalytic alpha-oxidation of aldehyde 6. The carbon core was constructed by a tandem Horner-Wadsworth-Emmons (HWE) reaction and an intramolecular Diels-Alder cyclization. All double bonds of 12 were made in a stereoselective manner by Wittig-type reactions. Selective formation of the monosulfate monoester was accomplished by one-pot excessive sulfation followed by kinetic hydrolysis of bissulfate 18 in 79% yield.
The retinal tolerance to bevacizumab in co-application with a recombinant tissue plasminogen activator
2007-03-23

The present study suggests that a subretinal injection of 20 microg/ml rt-PA in co-application with bevacizumab (0.25 mg/ml) for the treatment of massive subretinal haemorrhage seems possible. This is a safety study. Therefore, we did not test the clinical effectiveness of this combined treatment.
Prevalence of human papillomavirus types in women screened by cytology in Germany
2007-03-26

Abstract Incidence and mortality rates of cervical cancer are higher in Germany than in other Western European countries. Type‐specific human papillomavirus (HPV) distribution was investigated for the first time in Germany in an epidemiological study including 8,101 women. Women above the age of 30 years, self‐referring for cervical cancer screening, were enrolled in two study centers in Hannover (Northern Germany) and Tübingen (Southern Germany). Participants were screened by the Pap smear and the hybrid capture 2 (HC2) test using the high‐risk probe. All samples that were positive by the HC2 test were genotyped using the prototype PGMY09/11 PCR line blot assay. Most women in the study population had a negative Pap smear (96.7%). Prevalence of high‐risk type HPV detected by HC2 was 6.4% and prevalence of carcinogenic types detected by PGMY09/11 was 4.3%. Of the PGMY09/11 PCR‐positive women, 70.2% had a single infection, 28.1% had multiple infections and 1.7% remained uncharacterized. 32 different HPV types were detected using PGMY09/11 PCR. HPV 16, 31, 52, 51, 18, and 45 were the most common carcinogenic types in the study population. Among women with histologically confirmed high‐grade lesions HPV 16, 45, 58, 18, 31, 33, and 52 were the predominant types. These results provide valuable information for the management of HPV infections in Germany, both in terms of future strategies of screening and vaccination. J. Med. Virol. 79:616–625, 2007. © 2007 Wiley‐Liss, Inc.
Real-time observation of oxidation and photo-oxidation of rubrene thin films by spectroscopic ellipsometry
2007-03-26

The authors follow in real time and under controlled conditions the oxidation of the organic semiconductor rubrene grown on SiO2 using spectroscopic ellipsometry. They derive the complex dielectric function ε1+iε2 for pristine and oxidized rubrene showing that the oxidation is accompanied by a significant change of the optical properties, namely, the absorption. The authors observe that photo-oxidation of rubrene is orders of magnitude faster than oxidation without illumination. By following different absorption bands (around 2.5 and 4.0eV for pristine rubrene and around 4.9eV for oxidized rubrene) they infer that the observed photo-oxidation of these films involves non-Fickian diffusion mechanisms.
Gas‐chromatographic approach to probe the absence of molecular inclusion in enantioseparations by carbohydrates. Investigation of linear dextrins (“acyclodextrins”) as novel chiral stationary phases
2007-03-26

Abstract Acetylated/silylated maltooligosaccharides with different degrees of oligomerization have been tested as chiral stationary phases for enantioselective gas chromatography. The acyclic dextrin derivatives carrying tert‐ butyldimethylsilyl groups at the primary hydroxyl sites and acetyl groups at the secondary hydroxyl sites showed an unexpected ability for the enantioseparation of α‐amino acid derivatives and halogenated compounds, in addition to some underivatized chiral compounds. Some examples of an improved enantioselectivity invoked by the linear CSPs as compared to that of cyclic oligosaccharides are demonstrated in this work. The results highlight the role of the polar external surface of the selector in lieu of the well‐established inclusion mechanism of enantiorecognition by cyclic dextrins. Thus, the enantioseparation of chiral compounds on linear dextrin derivatives—devoid of a molecular cavity—sheds a new light on the mechanisms of enantiorecognition by cyclodextrin derivatives. In contrast to cyclodextrins, linear dextrins are readily accessible in both enantiomeric forms. Chirality, 2007. © 2007 Wiley‐Liss, Inc.