bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagenetic evolution of crystallite thickness distribution of illitic material in Carpathian shales, studied by the Bertaut-Warren-Averbach XRD method (MudMaster computer program)
Authors: Kotarba M. , Środoń J. 
Published: July 2002

AbstractThe MudMaster computer program, based on the modified Bertaut-Warren- Averbach (BWA) XRD method, was used in the study of diagenetic evolution of illitic material in shales. The illitic material was characterized by XRD as a mixture of illite-smectite (I-S) and discrete illite. The experimental conditions for complete dehydration of swelling clays, necessary in this method, were established for a climate of high relative humidity (RH >40%). It was found that the distribution of crystallite thickness of dehydrated illitic material of shales is described by the lognormal law, as was established earlier by the BWA method for pure I-S from pyroclastic rocks. The parameters characterizing this distribution evolve with depth: the mean crystallite thickness (Te), the distribution broadening (DW) and the parameter of a lognormal distribution (β2) increase, whereas the percentage of the most frequent crystallite thickness decreases. The observed scatter of values is not random but indicates fluctuations in the characteristics of the illitic material of shales. The results imply that the modified Scherrer technique of measuring mean crystal thickness from the broadening of XRD reflections can be extended at least to some shales.
Time-dependent changes of adsorption and wetting properties of pillared montmorillonites
Authors: Dékány I. , Seefeld V. , Lagaly G. 
Published: July 2002

AbstractThe changes of adsorption properties of uncalcined Al-pillared montmorillonite were studied. A soda-activated bentonite from Slovakia was reacted with polymeric hydroxoaluminium salt solutions. During storagein air at room temperature for three years, the basal spacing decreased by 0.15–0.2 nm; the specific surface area was reduced by 80% and the total pore volume by 40–60%. Adsorption experiments from ethanol-cyclohexane mixtures revealed the decreasing adsorption capacity and the increasing hydrophobicity. The changing surface character was also evident in the decrease in enthalpy of immersion in ethanol from 65.3 J/g to 8.3 J/g (sample B) and from 37.8 J/g to 5.2 J/g (sample C). The alteration probably arises from gradual formation of gibbsite-like interlayers and the redistribution of charges.
ATEM investigation of experimentally annealed sillimanite: new constraints for the SiO2–Al2O3 join
Authors: Raterron P. , Carpenter M. , Doukhan J.-C. 
Published: July 2002

AbstractFour samples of Fe-bearing prismatic sillimanite, containing ∼1 wt.% Fe2O3, were annealed experimentally at temperatures of 1465 and 1675°C, and pressures between 1 atm and 30 kbar. Transmission electron microscopy (TEM) and analytical TEM (ATEM) investigation of the samples reveal that the starting material partly transformed into mullite during the annealing, and that this process was assisted by partial melting. The exsolved partial melt (now a glass), observed at triple junctions and in the form of small precipitates (∼10–1000 nm in size) within the sillimanite matrix, contains >80 wt.% SiO2. It also contains ∼11 wt.% Al2O3, some FeO and detectable amounts of K2O and CaO. Dissociated c dislocations in sillimanite are preferential nucleation sites for SiO2-rich precipitates. The equilibrium compositions of residual sillimanite-mullite were measured with a 2 nm wide probe at the interface with the SiO2-rich glass in each sample after heat treatment. We used these equilibrium compositions to constrain the parameters of a point defect model for sillimanite mullitization proposed by Raterron et al. (1999). With the revised parameterization, it is now possible to calculate the position of the boundary between fields of mullite + melt and mullite in the SiO2–Al2O3 phase diagram, and to predict the effect of pressure on this boundary. However, to be used as a standard, this model still needs to be calibrated in the pure SiO2–Al2O3 system (without impurities such as iron).
Three compositional varieties of perovskite from kimberlites of the Lac de Gras field (Northwest Territories, Canada)
Authors: Chakhmouradian A. R. , Mitchell R. H. 
Published: July 2002

AbstractIn hypabyssal and crater-facies kimberlites of the Lac de Gras kimberlite field, perovskite occurs as reaction-induced rims on earlier-crystallized Ti-bearing minerals (magnesian ilmenite and priderite), inclusions in atoll spinels and discrete crystals in a serpentine-calcite mesostasis. The mineral is associated with spinels, apatite, monticellite, phlogopite, baryte, Fe-Ni sulphides, ilmenite, diopside and zircon. Uncommon accessory phases found in an assemblage with perovskite include titanite, monazite- (Ce), witherite, strontium-apatite, khibinskite, djerfisherite, wollastonite, pectolite, suolunite, hydroxyapophyllite and bultfonteinite. Three types of perovskite can be distinguished on the basis of composition: (I) REE-Nb-Al-poor perovskite with relatively high Sr and K contents (up to 2.2 and 0.6 wt.% oxides, respectively) occurring as mantles on priderite and inclusions in atoll spinels; (II) perovskite with elevated Al, Fe, Nb and LREE (up to 1.4, 8.3, 9.1 and 17.0 wt.% oxides, respectively) found as discrete crystals and rims on macrocrystic ilmenite; (III) perovskite significantly enriched in Na, Sr, Nb and LREE (up to 3.3, 3.4, 13.0 and 22.6 wt.% oxides, respectively) found as rims on perovskite I and II. The overwhelming majority of perovskite is represented by discrete crystals of type II. In some occurrences, this type of perovskite also has high Th contents (up to 5.5 wt.% ThO2) and Zr contents (up to 3.7 wt.% ZrO2). Textural evidence indicates that perovskite shows an overall evolutionary trend from the most primitive type I towards type III showing the highest Na, Nb and LREE contents. Perovskite of type I probably crystallized under relatively high pressures prior to the precipitation of MUM spinels. Perovskite II crystallized after magnesiochromite, pleonaste and MUM (magnesian ulvöspinel-magnetite) spinels, under increasing fO2. The most compositionally evolved type III formed during near-solidus re-equilibration of the earlier-crystallized perovskite. The compositional variation of the Lac de Gras perovskite can be adequately characterized in terms of five major end-members: CaTiO3 (perovskite), CeFeO3, NaNbO3 (lueshite), Na0.5LREE0.5TiO3 (loparite), and CaFe0.5Nb0.5O3 (latrappite).
Lattice defects in lawsonite: a TEM investigation
Authors: Cámara F. , Doukhan J. C. , Carpenter M. A. 
Published: July 2002

AbstractLattice defects in lawsonite have been studied by transmission electron microscopy. It is proposed that twinning and easy glide systems are 1/2[110] {110}; the easy glide planes are coincident with twin planes. This mineral displays high sensitivity to the electron beam, even at low temperatures. In situ precipitates appear as a consequence of beam irradiation. The precipitation takes places first on dislocations, then on twin boundaries and then in the matrix, causing ‘coffee-bean’ contrast features typical of precipitates. The studies were performed at low temperature (∼110 K) in order to investigate the low temperature displacive transitions from space group Cmcm to Pmcn and P21cn and elucidate their microscopic character. No characteristic microstructural texture, such as antiphase domains associated with the transition, were observed, however. This is probably due to the high mobility of protons under the electron beam. The development of regularly spaced dislocations along twin planes is hypothesized as the only evidence that a phase transition takes place at a nanoscale.
Discontinuation of fucose therapy in LADII causes rapid loss of selectin ligands and rise of leukocyte counts
Authors: Lühn Kerstin , Marquardt Thorsten , Harms Erik , Vestweber Dietmar 
Published: July 2002

Abstract
Leukocyte adhesion deficiency type II (LADII) is a rare inherited disorder of fucose metabolism. Patients with LADII lack fucosylated glycoconjugates, including the carbohydrate ligands of the selectins, leading to an immunodeficiency caused by the lack of selectin-mediated leukocyte-endothelial interactions. A simple and effective therapy has recently been described for LADII, based on the administration of oral fucose. Parallel to this treatment the lack of E- and P-selectin ligands on neutrophils was corrected, and high peripheral neutrophil counts were reduced to normal levels. This study reports that discontinuation of this therapy leads to the complete loss of E-selectin ligands within 3 days and of P-selectin ligands within 7 days. Peripheral neutrophil counts increased parallel to the decrease of selectin ligands. Selectin ligands reappeared promptly after resumption of the fucose therapy, demonstrating a causal relationship between fucose treatment and selectin ligand expression and peripheral neutrophil counts.
A novel regulator of G-protein signaling bearing GAP activity for Gαi and Gαq in megakaryocytes
Authors: Nagata Yuka , Oda Masaaki , Nakata Hiroko , Shozaki Yuka , Kozasa Tohru , Todokoro Kazuo 
Published: July 2002

AbstractThe regulator of G-protein signaling (RGS) negatively regulates the α subunit of G proteins by accelerating their intrinsic guanosine triphosphatase (GTPase) activity. Here are reported the isolation and characterization of a novel mouse RGS, termed RGS18, which is a new member of RGS subfamily B. Northern blot analysis showed that RGS18 messenger RNA was detected predominantly in spleen and hematopoietic cells, and immunohistochemical studies demonstrated that RGS18 was expressed in megakaryocytes, platelets, granulocytes/monocytes, and, weakly, in hematopoietic stem cells, but not in lymphocytes or erythrocytes. Although various subcellular localizations of RGS have been reported, RGS18 was found to be localized in cytoplasm in megakaryocytes. In vitro binding assays of RGS18 with megakaryocyte cell lysates with or without AlF4− treatment demonstrated that RGS18 specifically binds to 2 α subunits of the G protein, Gαi and Gαq. Furthermore, RGS18 clearly exhibited GTPase-activating protein (GAP) activity for Gαi and Gαq but not for Gαs or Gα12. In addition, chemokine stromal-derived factor 1 (SDF-1), which has been reported to stimulate megakaryocyte colony formation in the presence of thrombopoietin, affected the binding of RGS18 to Gαi but not to Gαq. Therefore, the newly isolated RGS18 turned out to be a new member of the RGS family bearing GAP activity for Gαi, which might be stimulated by SDF-1 in megakaryocytes, as well as for Gαq. Thus, RGS18 may play an important role in proliferation, differentiation, and/or migration of megakaryocytes.
Interferon-inducible protein 10, monokine induced by interferon gamma, and interferon-inducible T-cell alpha chemoattractant are produced by thymic epithelial cells and attract T-cell receptor (TCR) αβ+CD8+ single-positive T cells, TCRγδ+ T cells, and natural killer–type cells in human thymus
Authors: Romagnani Paola , Annunziato Francesco , Lazzeri Elena , Cosmi Lorenzo , Beltrame Chiara , Lasagni Laura , Galli Grazia , Francalanci Michela , Manetti Roberto , Marra Fabio , Vanini Vittorio , Maggi Enrico , Romagnani Sergio 
Published: July 2002

AbstractStrong reactivity for interferon-inducible protein 10 (IP-10), monokine induced by interferon gamma (Mig), and interferon-inducible T-cell alpha chemoattractant (I-TAC) was found in epithelial cells mainly localized to the medulla of postnatal human thymus. The CXC chemokine receptor common to the 3 chemokines (CXCR3) was also preferentially expressed in medullary areas of the same thymuses and appeared to be a property of 4 distinct populations: CD3+T-cell receptor (TCR) αβ+CD8+ single-positive (SP) T cells, TCRγδ+ T cells, natural killer (NK)–type cells, and a small subset of CD3+(low)CD4+CD8+TCRαβ+double-positive (DP) T cells. IP-10, Mig, and I-TAC showed chemoattractant activity for TCRαβ+CD8+ SP T cells, TCRγδ+ T cells, and NK-type cells, suggesting their role in the migration of different subsets of mature thymocytes during human thymus lymphopoiesis.
Changes in the biomechanical properties of neutrophils and endothelial cells during adhesion
Authors: Wang Qin , Chiang Eddie T. , Lim Mark , Lai Jean , Rogers Rick , Janmey Paul A. , Shepro David , Doerschuk Claire M. 
Published: July 2002

AbstractThis study examined changes in the biomechanical properties of cultured pulmonary microvascular endothelial cells (ECs) and neutrophils induced by adhesion of neutrophils to these ECs. The biomechanical properties of cells were evaluated using magnetic twisting cytometry, which measures the angular rotation of ferromagnetic beads bound to cells through antibody ligation on application of a specified magnetic torque. Adhesion of neutrophils to 24-hour tumor necrosis factor-α (TNF-α)–treated ECs, but not to untreated ECs, induced an increase in EC stiffness within 2 minutes, which was accompanied by an increase and a reorganization of F-actin in ECs. A cell-permeant, phosphoinositide-binding peptide attenuated the EC stiffening response, suggesting that intracellular phosphoinositides are required. The stiffening response was not inhibited by ML-7, a myosin light-chain kinase inhibitor, or BAPTA, an intracellular Ca2+ chelator. Moreover, the phosphorylation pattern of the regulatory myosin light chains was unaltered within 15 minutes of neutrophil adherence. These data suggested that the EC stiffening response appeared not to be mediated by myosin light-chain–dependent mechanisms. Concomitantly, neutrophil adhesion to 24-hour TNF-α–treated ECs also induced changes in the biomechanical properties of neutrophils compared to neutrophils bound to untreated ECs. Taken together, these results demonstrated that neutrophil adhesion to TNF-α–treated ECs induces changes in the biomechanical properties of both cell types through actin cytoskeletal remodeling. These changes may modulate neutrophil transmigration across the endothelium during inflammation.
Constitutive NF-κB maintains high expression of a characteristic gene network, including CD40, CD86, and a set of antiapoptotic genes in Hodgkin/Reed-Sternberg cells
Authors: Hinz Michael , Löser Peter , Mathas Stephan , Krappmann Daniel , Dörken Bernd , Scheidereit Claus 
Published: July 2002

AbstractConstitutively activated nuclear factor (NF)-κB is observed in a variety of neoplastic diseases and is a hallmark of the malignant Hodgkin and Reed-Sternberg cells (H/RS) in Hodgkin lymphoma. Given the distinctive role of constitutive NF-κB for H/RS cell viability, NF-κB–dependent target genes were searched for by using adenoviral expression of the super-repressor IκBΔN. A surprisingly small but characteristic set of genes, including the cell-cycle regulatory protein cyclin D2, the antiapoptotic proteins Bfl-1/A1, c-IAP2, TRAF1, and Bcl-xL, and the cell surface receptors CD86 and CD40 were identified. Thus, constitutive NF-κB activity maintains expression of a network of genes, which are known for frequent, marker-like expression in primary or cultured H/RS cells. Intriguingly, CD40, which is able to activate CD86 or Bcl-xL via NF-κB, is itself transcriptionally regulated by NF-κB through a promoter proximal binding site. NF-κB inhibition resulted in massive spontaneous and p53-independent apoptosis, which could be rescued by ectopic expression of Bcl-xL, underscoring its dominant role in survival of H/RS cells. Hence, NF-κB controls a signaling network in H/RS cells, which promotes tumor cell growth and confers resistance to apoptosis.
Roles of tumor necrosis factor-α receptor subtypes in the pathogenesis of the tristetraprolin-deficiency syndrome
Authors: Carballo Ester , Blackshear Perry J. 
Published: July 2002

AbstractTristetraprolin (TTP) is a member of the CCCH tandem zinc-finger class of proteins. It can bind to and destabilize mRNAs encoding tumor necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Conversely, mice deficient in TTP develop a complex syndrome characterized by cachexia, myeloid hyperplasia, and joint and skin inflammation. Studies using anti–TNF-α neutralizing antibodies demonstrated that this syndrome, at least in part, is a consequence of the excess production of TNF-α in the absence of TTP. To evaluate the role played by each TNF-α receptor in the pathogenesis of this syndrome, mice were generated that were deficient in TTP and either or both of the known TNF-α receptors (TNFRs), type 1 (TNFR1) and type 2 (TNFR2). Mice deficient in TTP and TNFR1, or in TTP and both receptors, were protected from developing the TNF-α–induced cachexia and inflammation. In contrast, mice deficient in TNFR2 were more severely affected than mice deficient in TTP alone, suggesting that TNFR2 might play a protective role in the development of the syndrome. In cultured cells derived from these mice, apparent cooperation between the TNFRs was required to achieve normal TNF-α–induced expression of TTP, TNF-α, and GM-CSF mRNAs. Finally, the results showed that TNFR1 plays an important role in mediating TNF-α–induced changes in TNF-α and GM-CSF mRNA stability.
Measuring nursing needs of stroke patients in clinical rehabilitation: a comparison of validity and sensitivity to change between the Northwick Park Dependency Score and the Barthel Index
Authors: Post M WM , Visser-Meily J MA , Gispen L SF 
Published: July 2002

Objective: To compare the content and convergent validity and the sensitivity to change of the Northwick Park Dependency Score (NPDS) to that of the Barthel Index in patients with stroke. Setting: Rehabilitation Centre De Hoogstraat, Utrecht, The Netherlands. Design: Inclusion of consecutive patients with stroke. Measurements at admission and every four weeks until ”nal measurement at discharge. Administration by nurses of NPDS, Barthel Index and nurses' global ratings of nursing dependency. Results: Thirty-one patients were included and 123 measurements were obtained. Median Barthel Index scores at admission and discharge were 11.2 and 17.8 respectively. At discharge, 58.6% of all patients obtained the best possible Barthel Index score, against 31.1% for the Basic Care Needs section and 87.1% for the Special Nursing Needs sections of the NPDS. Spearman correlations between NPDS and Barthel Index were very strong (0.82–0.92) at each measurement. Both the NPDS and the Barthel Index showed strong relationships with the global rating of nursing dependency (–0.82 and 0.70 respectively) and showed good sensitivity to change, Z-values for differences between admission and discharge were 4.06 ( p < 0.001) for the NPDS and 4.20 ( p < 0.001) for the Barthel Index. Most (9/12) nurses involved in this study judged the NPDS to provide better, more precise and complete information about the actual need for care of the patients. Conclusions: Validity and sensitivity to change of the NPDS were not superior to those of the Barthel Index but most nurses preferred the NPDS for future use.
Percutaneous endoscopic gastrostomy feeding in a district rehabilitation service
Authors: Thomson M A , Carverand A D , Sloan R L 
Published: July 2002

Objectives: To examine gender, diagnosis, age, reasons for feeding, nutritional status, complications, outcome and duration of feeding in patients who have required a percutaneous endoscopic gastrostomy (PEG) for nutritional support at a district rehabilitation unit in the six years since the service was established. To identify potential for improvements in the management of future patients. Design: Retrospective case note review of cases from 1992 to 1998. Setting: District rehabilitation service for ages 16–64 serving the population of Fife, Scotland (population circa 350 000). Subjects: All patients ( n = 42) who had been fed via a PEG feeding tube in the previous six years. Results: Forty-four PEG tube insertions had been conducted for 43 episodes of feeding in 42 patients. Five episodes of feeding were because of persistent vegetative state or low awareness state and 38 because of neurological swallowing impairment. Twenty-six (60%) patients were nutritionally depleted when PEG feeding was commenced. Twenty-seven (64%) patients experienced minor complications and 15 (34%) had no complications. At three months post procedure four (9.5%) patients had died and 21 (50%) had been discharged home. The mean duration of feeding on 31 October 1998 of the 20 patients (48%) who continued feeding at that date was 3.19 ± 1.89 (mean ± SD) years. Conclusions: Patients requiring PEG feeding in a district rehabilitation service have a range of diagnoses and the main indication for intervention is neurological swallowing impairment. The majority of patients were nutritionally depleted when feeding commenced and the reasons for this require further investigation.
Implications of Microscopic Satellites of the Primary and Extracapsular Lymph Node Spread in Patients With High-Risk Melanoma: Pathologic Corollary of Eastern Cooperative Oncology Group Trial E1690
Authors: Rao U.N.M. , Ibrahim J. , Flaherty L.E. , Richards J. , Kirkwood J.M. 
Published: July 2002

PURPOSE: To correlate the presence of extracapsular spread (ECS) of regional nodal metastases, and micrometastasis near the primary tumor, with disease outcome in the intergroup study E1690 in relation to the impact of recombinant interferon-alfa (rIFNα)-2b.PATIENTS AND METHODS: E1690 included 642 patients with American Joint Committee on Cancer stage IIB or III cutaneous melanoma. Patients were randomized into high- and low-dose rIFNα-2b treatment arms and an observation arm. Pathologic slides were reviewed for selected parameters from at least half of the subjects in all three arms. Evaluation of the primary tumor included notations regarding ulceration, mitotic activity, thickness, microscopic satellites (MS), and nodal ECS on a standardized pathology form. These data were collated in relation to relapse-free survival (RFS) and overall survival (OS) at 50 months’ follow-up and studied using Cox regression analysis.RESULTS: Ulceration, mitotic activity, thickness, and size of tumor-bearing lymph nodes did not show a statistically significant correlation with either OS or RFS across all treatment arms. The presence of MS was correlated with RFS (P = .0008) and OS (P = .05). ECS correlated with RFS (hazard ratio = 1.44, P = .032) but not OS (P = .11).CONCLUSION: The presence of MS (in 6% [18 of 308 patients]) had a significant adverse impact on both RFS (P = .0008) and OS (P = .053). Ulceration, mitotic activity, thickness, and number of positive lymph nodes had no significant effect on OS in this subset study (univariate or multivariate Cox analysis). The presence of ECS in lymph nodes had a significant adverse effect on RFS (P = .032) but not on OS.