bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of Wear of Roadheader Picks Using Numerical Simulations
Authors: Rojek Jerzy , Oñate Eugenio , Kargl Hubert , Labra Carlos , Akerman Jan , Restner Uwe , Lammer Egmont , Zarate Francisco 
Published: February 2008

AbstractThe paper presents prediction of wear of roadheader picks using numerical simulations. Estimation of wear has been included into the numerical model of rock cutting based on the discrete element method. The amount of wear is calculated using the classical formula of Archard. The wear model takes the influence of temperature by considering the hardness of the worn material as temperature dependent into account. The set of parameters for the discrete element model has been established by a calibration procedure based on numerical simulation of the unconfined compression and Brazilian tests, with the results of laboratory tests as reference data. After having established model parameters, numerical simulation of cutting process with a roadheader pick has been carried out. The simulation provides values and variation of cutting forces. Temperature increase due to frictional heat is obtained in the thermo‐mechanical simulation of cutting. Numerical analysis yields the wear profile as well as the tool shape evolution due to wear. The numerical model developed allows studying the wear intensity for different cutting process parameters. The developed method can be employed in the design of cutting heads and cutting operations in underground excavations with roadheaders.
Factors Influencing Disc Cutter Wear
Authors: Frenzel Christian , Käsling Heiko , Thuro Kurosch 
Published: February 2008

AbstractDisc cutter wear in mechanised tunnelling has a strong influence on costs and performance in hard rock and soil materials. Wear is affected by several geological and technical factors. Several aspects have been considered in prediction models and case studies. In this paper the essential technical influences are presented in a systematic way and are further analysed based on jobsite experience. Modifications in the operation of a TBM like adjustments of the cutterhead rotation or thrust lead to less disc cutter wear at comparable advance. A geological mapping during the tunnelling process, regular cutterhead inspections and tool wear measurements in combination with penetration tests will improve the work and results in a more economic tunnelling process.
The Influence of the Parameter “Temperature” on the Abrasiveness of Rock
Authors: Eberl Stefan , Restner Uwe , Galler Robert , Mali Heinrich 
Published: February 2008

AbstractThe article deals with the influence of temperature produced in the cutting process on rock abrasiveness and tool wear. Basically it was to clarify which effects take place when quartz or rock with significant quartz content is heated up to a certain temperature. Does the quartz jump from low into high quartz happening at 573 °C cause an increase in abrasiveness of mineral and rock or not? To find out, a certain number of Cerchar abrasiveness index tests were done for a detailed investigation of this topic. Additionally, to get a better understanding what really happens inside rock structure additionally other rock parameters like unconfined compressive strength, Brazilian tensile strength, ultrasonic wave velocity and density were determined on untreated and heated and subsequently cooled down rock samples. The final output of the research work showed that rocks show a very specific and significant reaction to thermal stresses induced into their structure resulting in a different behaviour regarding abrasiveness and fracturing.
Dichloroacetate‐ and trichloroacetate‐induced phagocytic activation and production of oxidative stress in the hepatic tissues of mice after acute exposure
Authors: Hassoun Ezdihar A. , Dey Soumyadeep 
Published: February 2008

AbstractDichoroacetate (DCA) and trichloroacetate (TCA) are by‐products formed during chlorination of the drinking water and were found to be hepatotoxic and hepatocarcinogenic in rodents. In this study, the abilities of the compounds to induce oxidative stress and phagocytic activation have been studied in B6C3F1 mice. Groups of mice were administered 300 mg/kg of either DCA or TCA, p.o, and were sacrificed after 6 or 12 h. Peritoneal lavage cells (PLCs) were isolated and assayed for superoxide anion (SA) production, and hepatic tissues were assayed for the production of SA, lipid peroxidation (LP), and DNA‐single strand breaks (SSBs). TCA resulted in significant production of SA in the PLCs, and in the production of SA, LP, and DNA‐SSBs in the hepatic tissues, 12 h after dosing, as compared with the control. DCA administration, on the other hand, resulted in significant increases in the productions of LP and DNA‐SSBs in the hepatic tissues at both time points, and in SA production in PLCs and hepatic tissues, 6 h after dosing. However, DCA‐induced increases in SA production in PLC and hepatic tissues declined at the 12‐h time point, reaching control level in the hepatic tissues. These results may implicate the contribution of phagocytic activation to the induction of oxidative stress in the hepatic tissues and also the role of SA production in the induction of LP and/or DNA damage in those tissues, in response to the compounds. The results also suggest studying the involvement of these mechanisms in the long‐term hepatotoxicity/hepatocarcinogencity of the compounds. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:27–34, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20210
Phosphorylation of Nrf2 in the transcription activation domain by casein kinase 2 (CK2) is critical for the nuclear translocation and transcription activation function of Nrf2 in IMR‐32 neuroblastoma cells
Authors: Apopa Patrick L. , He Xiaoqing , Ma Qiang 
Published: February 2008

AbstractThe antioxidant‐activated transcription factor nuclear factor erythroid 2‐related factor 2 (Nrf2) regulates the induction of cytoprotective genes against chemical toxicity and oxidative injuries. The role of phosphorylation in Nrf2 activation has been suggested but remains elusive. We report that phenolic antioxidant/pro‐oxidant tert‐butylhydroquinone (tBHQ) induced two forms of the Nrf2 protein in neuroblastoma cells (IMR‐32), which migrated as distinctive bands on SDS‐PAGE. In vitro treatment with λ phosphatase eliminated the slower migrating form and increased the amount of the faster migrating form of Nrf2. In vivo 32Pi‐phosphorylation resulted in 32Pi‐labeling of the Nrf2 protein in the presence of tBHQ that can be dephosphorylated by λ phosphotase, indicating that the slower migrating form is a phosphorylated Nrf2 protein and the faster form an unphosphorylated Nrf2. Unphosphorylated Nrf2 predominated in the cytoplasm, whereas the phosphorylated form preferentially localized in the nucleus. Nuclear Nrf2 can be dephosphorylated by λ phosphotase in vitro and be converted to the faster migrating form, implicating phosphorylation of Nrf2 in the cytoplasmic‐nuclear translocation of the protein. Deletional analyses from both the carboxyl‐ and amino‐ends revealed the transcription activation (TA) domains Neh4 (Nrf2‐ECH homology 4) and Neh5 (Nrf2‐ECH homology 5) as a major region necessary for the phosphorylation. The TA domains are characterized by the presence of multiple phosphorylation sites of casein kinase 2 (CK2). Moreover, CK2 phosphorylated the TA domains in vitro. Treatment with CK2 inhibitor 2‐dimethylamino‐4,5,6,7,‐tetrabromo‐1H‐benzimidazole (DMAT) blocked the induction of endogenous target genes of Nrf2 in cells and inhibited the TA activities of both the full length and the TA domains of Nrf2 to a large extent. Finally, phosphorylation of the TA domains correlated with the nuclear translocation of Nrf2 that was inhibited by DMAT in a concentration‐dependent manner. The findings demonstrated that phosphorylation of Nrf2 at the TA domains by CK2 is an integral component of Nrf2 activation necessary for the nuclear localization and transcription activation function of Nrf2 in neuroblastoma cells. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:63–76, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20212
Serum levels of variants of transthyretin down‐regulation in cholangiocarcinoma
Authors: Liu Liyun , Wang Jianing , Liu Bo , Dai Songwei , Wang Xiaomin , Chen Junzhou , Huang Lingyun , Xiao Xueyuan , He Dacheng 
Published: February 2008

AbstractBackgroundCholangiocarcinoma (CC) is devastating neoplasm and very few specific biomarkers could be used in clinical diagnosis. A study was taken to find novel serum biomarkers for CC.MethodsSurface enhanced laser desorption/ionization (SELDI) technology was used to analyze 427 serum samples including 56 CCs, 49 hepatobiliary diseases, 269 other cancer control, and 53 healthy individuals. The candidates were isolated and identified by SDS–PAGE, ESI/MS‐MS, Western blot, and immunoprecipitation. Liver functions of CC patients were examined and enzyme‐linked immunosorbent assay (ELISA) of transthyretin (TTR) and CA19‐9 were further performed in some sets of serum samples.Results13.76, 13.88, and 14.04 k m/z peaks in sera were significantly decreased in CC compared with the control groups (P < 0.001). Subsequently, these three peaks were identified as native TTR and its two variants. ELISA assay indicated that TTR levels were consistent with SELDI analysis in CC compared with healthy control and benign diseases of hepatobiliary (P < 0.001). Liver function test levels were obviously elevated for CC patients. TTR combining with CA19‐9 to differentiate CC from benign hepatobiliary diseases showed sensitivity and specificity were 98.2% and 100%, respectively.ConclusionThe levels of TTR were significantly down‐regulated in sera of CC patients and may be complementary markers of CA19‐9 in diagnosis for CC. J. Cell. Biochem. 104: 745–755, 2008. © 2008 Wiley‐Liss, Inc.
In vivo and in vitro effects of a HIF‐1α inhibitor, RX‐0047
Authors: Dikmen Z. Gunnur , Gellert Ginelle C. , Dogan Pakize , Yoon Heejeong , Lee Young Bok , Ahn Chang Ho , Shay Jerry W. 
Published: February 2008

AbstractHIF‐1α plays a major role in activating gene transcription and is important for maintaining homeostasis under hypoxic conditions. Since tumors are often in a hypoxic state, HIF‐1α is a potential target for the development of novel cancer therapeutics. This study was performed to determine the antitumoral efficacy of an antisense HIF‐1α inhibitor, RX‐0047 on different human cancer cell lines (MDA‐MB 231, HME50‐T, PC‐3, Panc‐1 and A549) in vitro. A549 lung cancer and PC‐3 prostate cancer cells containing a luciferase gene reporter were used for in vivo xenograft animal models. Progressive tumor development was quantified using live animal BLI (bioluminescence imaging) in addition to ex vivo imaging and histology. All cell lines tested were sensitive to inhibition of cell growth with 10 nM and higher ranges of RX‐0047, additionally RX‐0047 sensitizes cells to ionizing radiation treatments. Finally, RX‐0047 (30 mg/kg) inhibited the formation of human lung metastasis in xenograft mouse models and reduced tumor size in flank models. J. Cell. Biochem. 104: 985–994, 2008. © 2008 Wiley‐Liss, Inc.
CCAAT box is required for the induction of human thrombospondin‐1 gene by trichostatin A
Authors: Kang Jung‐Hoon , Kim Myung‐Jun , Chang Seo‐Yoon , Sim Sang Soo , Kim Myung‐Suk , Jo Yang‐Hyeok 
Published: February 2008

AbstractHistone deacetylase (HDAC) inhibitors have been reported to inhibit angiogenesis as well as tumor growth. Thrombospondin‐1 (TSP1) has been recognized as a potent inhibitor of angiogenesis. Such an action of TSP1 may account for the effect of HDAC inhibitors. In the present study, we investigated the molecular mechanism by which trichostatin A, a HDAC inhibitor, induces the expression of TSP1 gene. Trichostatin A increased both mRNA and protein levels of TSP1 in HeLa cells. Promoter and actinomycin D chase assays showed that trichostatin A‐induced TSP1 expression was regulated at the transcriptional level without changing mRNA stability. CCAAT box on the TSP1 promoter was found to primarily mediate the trichostatin A response by deletion and mutation analyses of the TSP1 promoter. Electrophoretic mobility shift assay indicated that CCAAT‐binding factor (CBF) was specifically bound to the CCAAT box of TSP1 promoter. Moreover, chromatin immunoprecipitation assay showed that trichostatin A increased the binding of acetylated form of histone H3 to the CCAAT box region of TSP1 promoter. Taken together, these results strongly suggest that trichostatin A activates the transcription of TSP1 gene through the binding of transcription factor CBF to CCAAT box and the enhanced histone acetylation. Thus, the present study provides the clue that the inhibition of angiogenesis by trichostatin A is accomplished through the upregulation of TSP1, the anti‐angiogenic factor. J. Cell. Biochem. 104: 1192–1203, 2008. © 2008 Wiley‐Liss, Inc.
Revisiting ankyrin–InsP3receptor interactions: Ankyrin‐B associates with the cytoplasmic N‐terminus of the InsP3receptor
Authors: Kline Crystal F. , Cunha Shane R. , Lowe John S. , Hund Thomas J. , Mohler Peter J. 
Published: February 2008

AbstractInositol 1,4,5‐trisphosphate (InsP3) receptors are calcium‐release channels found in the endoplasmic/sarcoplasmic reticulum (ER/SR) membrane of diverse cell types. InsP3receptors release Ca2+from ER/SR lumenal stores in response to InsP3generated from various stimuli. The complex spatial and temporal patterns of InsP3receptor‐mediated Ca2+release regulate many cellular processes, ranging from gene transcription to memory. Ankyrins are adaptor proteins implicated in the targeting of ion channels and transporters to specialized membrane domains. Multiple independent studies have documented in vitro and in vivo interactions between ankyrin polypeptides and the InsP3receptor. Moreover, loss of ankyrin‐B leads to loss of InsP3receptor membrane expression and stability in cardiomyocytes. Despite extensive biochemical and functional data, the validity of in vivo ankyrin–InsP3receptor interactions remains controversial. This controversy is based on inconsistencies between a previously identified ankyrin‐binding region on the InsP3receptor and InsP3receptor topology data that demonstrate the inaccessibility of this lumenal binding site on the InsP3receptor to cytosolic ankyrin polypeptides. Here we use two methods to revisit the requirements on InsP3receptor for ankyrin binding. We demonstrate that ankyrin‐B interacts with the cytoplasmic N‐terminal domain of InsP3receptor. In summary, our findings demonstrate that the ankyrin‐binding site is located on the cytoplasmic face of the InsP3receptor, thus validating the feasibility of in vivo ankyrin–InsP3receptor interactions. J. Cell. Biochem. 104: 1244–1253, 2008. © 2008 Wiley‐Liss, Inc.
Acidic pH stimulates the production of the angiogenic CXC chemokine, CXCL8 (interleukin‐8), in human adult mesenchymal stem cells via the extracellular signal‐regulated kinase, p38 mitogen‐activated protein kinase, and NF‐κB pathways
Authors: Bischoff David S. , Zhu Jian‐Hua , Makhijani Nalini S. , Yamaguchi Dean T. 
Published: February 2008

AbstractBlood vessel injury results in limited oxygen tension and diffusion leading to hypoxia, increased anaerobic metabolism, and elevated production of acidic metabolites that cannot be easily removed due to the reduced blood flow. Therefore, an acidic extracellular pH occurs in the local microenvironment of disrupted bone. The potential role of acidic pH and glu‐leu‐arg (ELR+) CXC chemokines in early events in bone repair was studied in human mesenchymal stem cells (hMSCs) treated with medium of decreasing pH (7.4, 7.0, 6.7, and 6.4). The cells showed a reciprocal increase in CXCL8 (interleukin‐8, IL‐8) mRNA levels as extracellular pH decreased. At pH 6.4, CXCL8 mRNA was induced >60× in comparison to levels at pH 7.4. hMSCs treated with osteogenic medium (OGM) also showed an increase in CXCL8 mRNA with decreasing pH; although, at a lower level than that seen in cells grown in non‐OGM. CXCL8 protein was secreted into the medium at all pHs with maximal induction at pH 6.7. Inhibition of the G‐protein‐coupled receptor alpha, Gαi, suppressed CXCL8 levels in response to acidic pH; whereas phospholipase C inhibition had no effect on CXCL8. The use of specific mitogen‐activated protein kinase (MAPK) signal transduction inhibitors indicated that the pH‐dependent increase in CXCL8 mRNA is due to activation of ERK and p38 pathways. The JNK pathway was not involved. NF‐κB inhibition resulted in a decrease in CXCL8 levels in hMSCs grown in non‐OGM. However, OGM‐differentiated hMSCs showed an increase in CXCL8 levels when treated with the NF‐κB inhibitor PDTC, a pyrrolidine derivative of dithiocarbamate. J. Cell. Biochem. 104: 1378–1392, 2008. © 2008 Wiley‐Liss, Inc.
Epinephrine increases DNA synthesis via ERK1/2s through cAMP, Ca2+/PKC, and PI3K/Akt signaling pathways in mouse embryonic stem cells
Authors: Kim Mi Ok , Na Sun Im , Lee Min Young , Heo Jung Sun , Han Ho Jae 
Published: February 2008

AbstractEpinephrine is a catecholamine that plays important roles in regulating a wide variety of physiological systems by acting through the adrenergic receptors (ARs). The cellular responses to AR stimulation are mediated through various signaling pathways. Therefore, this study examined the effects of epinephrine on DNA synthesis and related signaling molecules in mouse embryonic stem cells (ESCs). Epinephrine increased DNA synthesis in a dose‐ and time‐dependent manner, as determined by the level of [3H]‐thymidine incorporation. AR subtypes (α1A, α2A, β1, β2, and β3) were expressed in mouse ESCs and their expression levels were increased by epinephrine. In this experiment, epinephrine increased cAMP levels, intracellular Ca2+ concentration ([Ca2+]i), and translocation of protein kinase C (PKC) from the cytosol to the membrane compartment. In addition, we observed Akt phosphorylation in response to epinephrine; this was stimulated by phosphorylation of the epidermal growth factor receptor (EGFR). Epinephrine also induced phosphorylation of ERK1/2 (p44/42 MAPKs), while inhibition of PKC or Akt blocked this phosphorylation. Epinephrine increased the mRNA levels of proto‐oncogenes (c‐fos, c‐jun, c‐myc), while inhibition of ERK1/2 decreased these mRNA levels. In experiments aimed at examining the involvement of cell cycle regulatory proteins, epinephrine increased the levels of cyclin E/cyclin‐dependent kinase 2 (CDK2) and cyclin D1/cyclin‐dependent kinase 4 (CDK4). In conclusion, epinephrine stimulates DNA synthesis via ERK1/2 through cAMP, Ca2+/PKC, and PI3K/Akt signaling pathways in mouse ESCs. J. Cell. Biochem. 104: 1407–1420, 2008. © 2008 Wiley‐Liss, Inc.
Study of galacto‐oligosaccharide formation from lactose using Pectinex Ultra SP‐L
Authors: Cardelle‐Cobas Alejandra , Villamiel Mar , Olano Agustin , Corzo Nieves 
Published: February 2008

AbstractBACKGROUND:Galacto‐oligosaccharides (GOS) are synthesised from lactose by transglycosylation using β‐galactosidase (EC 3.2.1.23) and are recognised as prebiotics. The commercial enzyme preparation Pectinex Ultra SP‐L produced by Aspergillus aculeatus possesses β‐galactosidase activity; however, because its use has been directed towards the formation of 6′‐β‐galactosyl‐lactose, no data have been reported on the formation of other GOS. Since the composition of the oligosaccharide mixture obtained during lactose hydrolysis may affect the prebiotic properties, in this study the influence of various parameters (pH, temperature, time and enzyme and lactose concentrations) on the formation of GOS using Pectinex Ultra SP‐L was investigated.RESULTS:High‐performance anion exchange chromatography with pulsed amperometric detection (HPAEC‐PAD) analysis allowed the detection of disaccharides other than lactose, trisaccharides and minor amounts of higher‐molecular‐weight GOS. The main GOS formed were a trisaccharide identified as β‐D‐Galp‐(1 → 6)‐Lac (6′‐β‐galactosyl‐lactose) and a disaccharide identified as β‐D‐Galp‐(1 → 6)‐D‐Gal (galactobiose). Other GOS detected were tentatively identified as β‐D‐Galp‐(1 → 6)‐D‐Glc (allolactose), β‐D‐Galp‐(1 → 3)‐D‐Glc and β‐D‐Galp‐(1 → 3)‐Lac. Trisaccharide formation was favoured by a pH increase from 4.5 to 6.5, whereas the disaccharide content increased as the pH decreased, reaching a level of 11% at pH 4.5. 6′‐β‐Galactosyl‐lactose production increased gradually with increasing temperature, attaining a maximum value of 17% at 60 °C after 7 h, whereas disaccharide formation was optimal at 50 °C, reaching a level of 10% after 24 h.CONCLUSION:The results indicate that Pectinex Ultra SP‐L can be used to obtain GOS mixtures of different composition depending on the operating conditions. It has been shown for the first time that Pectinex Ultra SP‐L can be used for the selective formation of disaccharides. Copyright © 2008 Society of Chemical Industry
Study of Uniaxially Stretched Isotactic Poly(propylene) by 1H Solid‐State NMR and IR Spectroscopy
Authors: Hedesiu Cristian , Demco Dan E. , Remerie Klaas , Blümich Bernhard , Litvinov Victor M. 
Published: February 2008

AbstractChanges in the amount of the rigid, semi‐rigid and soft fractions, molecular mobility and domain thickness of uniaxially stretched iPP were investigated as a function of temperature, draw ratio, drawing temperature and drawing rate. Correlations are established between the thicknesses of rigid domains and the amount of the rigid fractions of uniaxially stretched iPP. Also established are correlations between the thickness of rigid domains and the molecular mobility of the rigid fraction of uniaxially stretched iPP. The drawing temperature has an important effect on the strain‐induced transformation of the spherulitic morphology of iPP to a fibrillar one.magnified image
Novel pH‐ and Temperature‐Responsive Block Copolymers with Tunable pH‐Responsive Range
Authors: He Chaoliang , Zhao Changwen , Chen Xuesi , Guo Zhaojun , Zhuang Xiuli , Jing Xiabin 
Published: February 2008

AbstractA series of novel pH‐ and temperature‐responsive diblock copolymers composed of poly(N‐isopropylacrylamide) (PNIPAM) and poly[(L‐glutamic acid)‐co‐(γ‐benzyl L‐glutamate)] [P(GA‐co‐BLG)] were prepared. The influence of hydrophobic benzyl groups on the phase transition of the copolymers was studied for the first time. With increasing BLG content in P(GA‐co‐BLG) block, the thermal phase transition of the diblock copolymer became sharper at a designated pH and the critical curve of phase diagram of the diblock copolymer shifted to a higher pH region. Notably, when the BLG content in P(GA‐co‐BLG) block was more than 30 mol.‐%, the diblock copolymer responded sharply to a narrow pH change in the region of pH 7.4–5.5.magnified image
Design and Synthesis of a New Conjugated Polyelectrolyte as a Reversible pH Sensor
Authors: Xu Qingling , An Lingling , Yu Minghui , Wang Shu 
Published: February 2008

AbstractA highly pH sensitive water‐soluble polyfluorene derivative (PFP‐aa) has been designed and synthesized by Suzuki coupling reaction. The PFP‐aa contains two amino and four carboxylic acid groups in each repeat unit (RU). The protonation and deprotonation of both the carboxylate and amine are controlled by medium pH values. The polymer charge is anticipated to control electrostatic repulsion between polymer chains and lead to different levels of aggregation behaviors. Different fluorescent responses of the PFP‐aa are demonstrated as the environmental pH is changed from 3 to 12. Different sugars can bind to boronic acid to form boronic esters with different binding constants following proton release, thus generating diverse changes in pH. It is demonstrated that PFP‐aa can be used as a pH sensor to detect D‐fructose.magnified image