bluuebunny/crossref_metadata_2025 huggingface dataset:
Protease activity of CND41, a chloroplast nucleoid DNA‐binding protein, isolated from cultured tobacco cells
Authors: Murakami Shinya , Kondo Yoshihiko , Nakano Takeshi , Sato Fumihiko
Published: July 2002

CND41 is a 41 kDa DNA‐binding protein isolated from chloroplast nucleoids of cultured tobacco cells. The presence of the active domain of aspartic protease in the deduced amino acid sequence of CND41 suggests that it has proteolytic activity. To confirm this, CND41 was highly purified from cultured tobacco cells and its proteolytic activity was characterized with fluorescein isothiocyanate‐labeled hemoglobin as the substrate. The purified CND41 had strong proteolytic activity at an acidic pH (pH 2–4). This activity was inhibited by various chemicals, including the nucleoside triphosphates, NADPH, Fe3+ and sodium dodecyl sulfate.
Sensitive assay of RNA interference in Drosophila and Chinese hamster cultured cells using firefly luciferase gene as target
Authors: Ui-Tei Kumiko , Zenno Shuhei , Miyata Yuhei , Saigo Kaoru
Published: July 2002

A sensitive cellular assay system for RNA interference was developed using the firefly luciferase gene as target. RNA interference was noted not only in Drosophila cultured cells but Chinese hamster cells (CHO‐K1) as well, although double‐stranded RNA required for the latter was 2500 times more than for the former. Cognate double‐stranded RNA as short as 38 bp was found to be still capable of inducing RNA interference in Drosophila cultured cells.
Regulation of tumour necrosis factor α mRNA stability by the mitogen‐activated protein kinase p38 signalling cascade
Authors: Brook Matthew , Sully Gareth , Clark Andrew R , Saklatvala Jeremy
Published: July 2002

The translation of tumour necrosis factor α (TNFα) mRNA is regulated by the stress‐activated protein kinase p38, which also controls the stability of several pro‐inflammatory mRNAs. The regulation of TNFα gene expression in a mouse macrophage cell line RAW264.7 was re‐examined using an inhibitor of stress‐activated protein kinases. Stimulation of these cells with bacterial lipopolysaccharide resulted in stabilisation of TNFα mRNA, which was reversed by specific inhibition of p38. An adenosine/uridine‐rich element from the TNFα 3′ untranslated region conferred p38‐sensitive decay in a tetracycline‐regulated mRNA stability assay. Therefore the p38 pathway also controls TNFα mRNA turnover.
Downregulation of MDM2 stabilizes p53 by inhibiting p53 ubiquitination in response to specific alkylating agents
Authors: Inoue Tomomi , Geyer Rory K , Yu Zhong Kang , Maki Carl G
Published: July 2002

p53 is stabilized in response to DNA damaging stress. This stabilization is thought to result from phosphorylation in the N‐terminus of p53, which inhibits p53:MDM2 binding, and prevents MDM2 from promoting p53 ubiquitination. In this report, the DNA alkylating agents mitomycin C (MMC) and methylmethane sulfonate (MMS), as well as UV radiation, stabilized p53 in a manner independent of phosphorylation in p53 N‐terminus. This stabilization coincided with decreased levels of MDM2 mRNA and protein, and a corresponding decrease in p53 ubiquitination. Importantly, MDM2 overexpression inhibited the stabilization of p53 and decrease in ubiquitination following MMC, MMS, and UV treatment. This indicates that downregulation of MDM2 contributes to the stabilization of p53 in response to these agents.
Calnexin can interact with N‐linked glycans located close to the endoplasmic reticulum membrane
Authors: Andersson Helena , Nilsson IngMarie , Heijne Gunnar von
Published: July 2002

Abstract Calnexin is a central component of the ‘quality control’ system in the endoplasmic reticulum (ER). Calnexin binds to monoglycosylated oligosaccharides on incompletely folded soluble and membrane proteins in the lumen of the ER and prevents exit from the organelle. We have previously found that the oligosaccharide transferase enzyme can add glycosyl moieties to a membrane protein when the acceptor site is as close as 12–13 residues away from the nearest transmembrane segment (J. Biol. Chem. 268, 5798). We now show that calnexin can bind to oligosaccharides located this close to the membrane, suggesting that its binding site is held at a similar distance from the membrane as is the active site of the oligosaccharide transferase. We further show that calnexin can bind efficiently to glycosylated but not to non‐glycosylated forms of a bacterial inner membrane protein, suggesting that it does not have a general affinity for non‐glycosylated proteins.
The conformation of an inhibitor bound to the gastric proton pump
Authors: Middleton David A. , Robins Rachel , Feng Xiaolong , Levitt Malcolm H. , Spiers Ian D. , Schwalbe Carl H. , Reid David G. , Watts Anthony
Published: July 2002

Substituted imidazo[1,2‐a]pyridines are pharmaceutically important small molecule inhibitors of the gastric H+/K+‐ATPase, the membrane‐bound therapeutic target for peptic ulcer disease. A non‐perturbing analytical technique, rotational resonance NMR spectroscopy, was used to measure a precise (to ±0.2 Å) distance between atomic sites in a substituted imidazo[1,2‐a]pyridine, TMPIP, bound to H+/K+‐ATPase at its high‐affinity site in the intact, native membrane. The structural analysis of the enzyme–inhibitor complex revealed that the flexible moiety of TMPIP adopts a ‘syn‐type’ conformation at its site of action. Hence, the conformation of an inhibitor has been resolved directly under near‐physiological conditions, providing a sound experimental basis for rational design of many active compounds of pharmaceutical interest. Chemically restraining the flexible moiety of compounds like TMPIP in the syn‐type binding conformation was found to increase activity by over 2 orders of magnitude. Such information is normally only available after extensive synthesis of related compounds and multiple screening approaches.
Comparison of H5 and H8 relaxation rates of a 2H/13C/15N labeled RNA oligonucleotide with selective protonation at C5 and C8
Authors: Nikonowicz E.P , Kalurachchi K , DeJong E
Published: July 2002

Uniformly 13C/15N enriched ribonucleotide monophosphates have been prepared with extensive deuterium enrichment of the non‐exchangeable positions. The purine C8 and pyrimidine C5 base positions were selectively protonated prior to incorporation of the individual nucleotide triphosphates into an RNA oligonucleotide. The longitudinal and transverse relaxation rates of the H8 and H5 resonances of this deuterated molecule were compared with the relaxation rates of the corresponding protonated, 13C/15N enriched RNA molecule. Deuteration disrupts the efficiency of 1H–1H dipolar relaxation and reduces the longitudinal and transverse magnetization relaxation rates on average to 25% and 68%, respectively, of the values measured for the non‐deuterated RNA molecule. Importantly, the longitudinal relaxation rates remain sufficiently rapid (>1s−1) to permit the use of short recovery delays in multidimensional NMR experiments without significant loss of sensitivity.
Interaction of SecB with soluble SecA1
Authors: den Blaauwen Tanneke , Terpetschnig Ewald , Lakowicz Joseph R , Driessen Arnold J.M
Published: July 2002

The preprotein binding molecular chaperone SecB functions by preventing the premature folding of the preprotein in the cytosol, and targeting it to the peripheral subunit SecA of the translocase at the cytoplasmic membrane. The nature of the interaction of SecB with soluble SecA was studied by fluorescence anisotropy spectroscopy of Ru(bpy)2(dcbpy)‐labeled SecA in the presence of increasing concentrations of SecB. A more than 50‐fold difference in affinity for the cytosolic SecA compared to translocase associated SecA seems to prevent unproductive binding of SecB to the cytosolic SecA and stresses its targeting function.
Regulation of ZiRF1 and basal SP1 transcription factor MRE‐binding activity by transition metals
Authors: Remondelli P. , Moltedo O. , Leone A.
Published: July 2002

The metal‐dependent activation of metallothionein (MT) genes requires the interaction of positive trans‐activators (MRFs) with metal‐regulatory (MRE) regions of MT promoters. In this report, we examined the role of transition metals in modulating the MRE‐binding activities of two different MRE‐binding proteins: the metal‐regulated factor ZiRF1 and the basal factor SP1. We showed the ability of both proteins to interact with a similar sequence specificity with the cognate target site (MRE‐S) of another known MRE‐binding protein, mMTF1. We next evaluated the role of metal ions in modulating the MRE‐binding activity of recombinant ZiRF1 and basal SP1 proteins by measuring the effect of different metal chelators on DNA interaction. We observed a dose‐dependent inhibition of the GST‐ZiRF1/MRE‐binding activity using three different metal chelators: EDTA, 1,10 PHE and TPEN. Interestingly, EDTA treatment failed to inhibit the recombinant SP1 MRE‐binding activity while the effect of 1,10 PHE was comparable to that obtained analyzing 1,10 PHE‐treated GST‐ZiRF1. The MRE‐binding complexes detected in cell extracts showed a response to metal chelator treatment very similar to that displayed by the recombinant ZiRF1 and SP1 proteins. The hypothesis of mutual interactions of both basal and metal‐regulated transcription factors with the same metal‐regulatory regions is discussed.
Presence of paraoxonase in human interstitial fluid
Authors: Mackness Michael I , Mackness Bharti , Arrol Sharon , Wood Grahame , Bhatnagar Deepak , Durrington Paul N
Published: July 2002

Human serum paraoxonase (PON1) is postulated to have anti‐atherosclerotic properties through its ability to prevent lipid peroxide generation on LDL. However, in order to perform this role it must be present in interstitial fluid, to prevent LDL oxidation which takes place in the sub‐intimal space of the artery wall. The PON1 activity in interstitial fluid was 15.7 (2.3–183.0) (median (range)) nmol/min/ml compared to 105.3 (74.6–323.9) nmol/min/ml in serum. The PON1 concentration in interstitial fluid was found to be 20.2 (1.1–78.1) μg/ml (median (range)) compared to 109.6 (11.1–485.7) μg/ml in serum. Interstitial fluid PON1 concentration was dependent on the interstitial fluid apo AI concentration (r=0.690,P<0.005) indicating PON1 remained associated with HDL. However, the ratio of PON1 concentration to apo AI was lower in interstitial fluid (0.60±0.20) than in the serum (0.95±0.18) (P<0.001) indicating sequestration of PON1 in the sub‐intimal space. Therefore, PON1 is present and active in interstitial fluid where it can perform its anti‐atherosclerotic function.
How platelet aggregation affects B16BL6 melanoma cell trafficking
Authors: Koike Chieko , Watanabe Manabu , Isoai Atsushi , Kumagai Hiromichi , Tsukada Hideo , Irimura Tatsuro , Okada Shoji , Oku Naoto
Published: July 2002

In blood‐borne metastasis, intravasated metastatic tumor cells are thought to localize at the target site via a series of processes involving platelet aggregation, adhesion to endothelium, and invasion through the basal membrane. In the present study, we examined how platelet aggregation contributes to the trafficking of metastatic tumor cells in vivo by use of an inhibitor of platelet aggregation. Highly invasive B16BL6 melanoma cells were labeled with [2‐18F]2‐fluoro‐2‐deoxy‐d‐glucose and injected into mice to determine cell trafficking non‐invasively by positron emission tomography. Both platelet aggregation inhibitor cyclo(RSarDPhg), which could not inhibit metastasis, and metastatic inhibitor cyclo(GRGDSPA) suppressed the accumulation of B16BL6 cells in the lung by about 12%, suggesting that platelet aggregation partly affects cell trafficking but not to a great extent, and that platelet aggregation is not the essential step for B16BL6 cell arrest in targets.
Stabilization of photosystem II reaction centers: influence of bile salt detergents and low pH
Authors: Gall Bernhard , Scheer Hugo
Published: July 2002

Rapid deterioration of samples is a major obstacle in research on the isolated reaction center of photosystem II. Its stability was tested systematically using a wide range of detergents, varying pH and temperature. Stability and activity did not depend on ionic properties of detergents or on critical micellar concentration. However, both were significantly increased by bile salt detergents in the dark as well as in the light. Low pH (5.5) and low temperature further improved stability. The results suggest that in particular the zwitterionic bile salt detergent, CHAPS, in pH 5.5 buffers is a very useful detergent and even superior to dodecylmaltoside for work with photosystem II reaction centers.
Engineering of solvent‐exposed loops in Escherichia coli β‐galactosidase
Authors: Feliu Jordi X , Villaverde Antonio
Published: July 2002

The Escherichia coli β‐galactosidase is a high molecular mass tetrameric enzyme extensively used as a molecular marker. Despite its proven utility as a partner in fusion proteins, previous attempts to generate insertional mutants rendered inactive or poorly active enzymes, hampering its further engineering for the construction of multifunctional enzymes. We have explored several solvent‐exposed loops on the tetramer, namely those spanning residues 246–254, 271–287, 578–584, 770–773, and 793–806, as acceptor sites to accommodate functional protein segments on the surface of active β‐galactosidase enzymes. An RGD‐containing antigenic peptide positioned in these sites interacts efficiently with specific monoclonal antibodies as well as target integrins on the surface of mammalian cells. The resulting chimeric enzymes are soluble, stable, produced in high yields and enzymatically active. Moreover, the identified insertion sites could be appropriated for the design of promising β‐galactosidase‐based molecular sensors.
Targeted disruption of the mouse phospholipase C β3 gene results in early embryonic lethality
Authors: Wang Shu , Gebre-Medhin Samuel , Betsholtz Christer , Stålberg Peter , Zhou Yinghua , Larsson Catharina , Weber Gunther , Feinstein Ricardo , Öberg Kjell , Gobl Anders , Skogseid Britt
Published: July 2002

In order to investigate the biological function of phosphatidylinositol‐specific phospholipase C (PLC) we generated mutant mice by gene targeting. Homozygous inactivation of PLCβ3 is lethal at embryonic day 2.5. These mutants show poor embryonic organization as well as reduced numbers of cells. Identical phenotypes were recorded in homozygous mutants generated from two independently targeted embryonic stem cell clones. Heterozygous mutant mice, however, are viable and fertile for at least two generations. We also showed that mouse PLCβ3 is expressed in unfertilized eggs, 3‐cell and egg cylinder stages of embryos. In conclusion, these results indicate that PLCβ3 expression is essential for early mouse embryonic development.
Serum responsiveness of the rat PCNA promoter involves the proximal ATF and AP‐1 sites
Authors: Liu Yin-Chang , Chang Hsueh-Wei , Lai Yi-Chyi , Ding Sheue-Ting , Ho Ji-Ling
Published: July 2002

We have previously shown that the rat PCNA (proliferating cell nuclear antigen) gene promoter is responsive to serum stimulation. In this study, the sequence of the promoter responsive to serum stimulation has been localized in the region between nucleotides −70 and +125 relative to the transcription initiation site. This region contains an ATF site (nucleotides −51 to −44) and an AP‐1 site (nucleotides −64 to −58). Mutation at either the ATF or the AP‐1 site reduced the serum responsiveness of the promoter. In gel mobility shift assays, nuclear extracts from serum stimulated cells, compared to those from quiescent cells, exhibit an increasing binding activity toward a promoter related oligonucleotide (−70 to −42) which includes the ATF site and the AP‐1 site. Formation of the DNA:protein complexes requires the simultaneous involvement of ATF and AP‐1 sites as either element can abrogate the complexes in the competition experiment. Both the distance and sequence are essential to complex formation. Moreover, ATF‐1 but not ATF‐2 (or CREB) has been identified as a major component of the complexes in the antibody supershift or interference experiment. The results of this study suggest that ATF‐1 in association with other factors is involved in regulating the serum stimulation of the rat PCNA promoter activity via the proximal ATF and AP‐1 sites.
Synechocystis sp. slr0787 protein is a novel bifunctional enzyme endowed with both nicotinamide mononucleotide adenylyltransferase and ‘Nudix' hydrolase activities
Authors: Raffaelli Nadia , Lorenzi Teresa , Amici Adolfo , Emanuelli Monica , Ruggieri Silverio , Magni Giulio
Published: July 2002

Synechocystis sp. slr0787 open reading frame encodes a 339 residue polypeptide with a predicted molecular mass of 38.5 kDa. Its deduced amino acid sequence shows extensive homology with known separate sequences of proteins from the thermophilic archaeon Methanococcus jannaschii. The N‐terminal domain is highly homologous to the archaeal NMN adenylyltransferase, which catalyzes NAD synthesis from NMN and ATP. The C‐terminal domain shares homology with the archaeal ADP‐ribose pyrophosphatase, a member of the ‘Nudix' hydrolase family. The slr0787 gene has been cloned into a T7‐based vector for expression in Escherichia coli cells. The recombinant protein has been purified to homogeneity and demonstrated to possess both NMN adenylyltransferase and ADP‐ribose pyrophosphatase activities. Both activities have been characterized and compared to their archaeal counterparts.
Human members of the SCO1 gene family: complementation analysis in yeast and intracellular localization
Authors: Paret Claudia , Ostermann Kai , Krause-Buchholz Udo , Rentzsch Anja , Rödel Gerhard
Published: July 2002

Cytochrome c oxidase is a multiprotein complex in the mitochondrial membrane whose biogenesis requires a number of proteins besides the structural subunits. Several yeast proteins as well as a human disease‐related protein have been reported which are involved in cytochrome c oxidase assembly. The S. cerevisiae Sco1p protein has been implicated in the transfer of copper to cytochrome c oxidase subunits Cox1p and/or Cox2p. Here we report on the complementation behavior in yeast of two recently identified ScSco1p homologs of chromosome 17 and chromosome 22 from human. When allotropically expressed in yeast, both genes fail to complement the lack of the ScSCO1 gene. However, a chimera of the N‐terminal half of ScSco1p and the C‐terminal half of the chromosome 17 homolog does substitute for the ScSco1p function. Interestingly, the respective chimera with the human homolog of chromosome 22 is not able to complement. Expression of EGFP fusions in HeLa cells shows that both human ScSco1p homologs are located in the mitochondria of human cells.
Clusterin (SGP‐2) gene expression is cell cycle dependent in normal human dermal fibroblasts
Authors: Bettuzzi S , Astancolle S , Guidetti G , Moretti M , Tiozzo R , Corti A
Published: July 2002

In confluent human dermal fibroblasts brought to quiescence (G0) by serum starvation, the S phase peaked at 24 h after serum re‐addiction and G2/M phase peaked at 36 h. This was confirmed by titration of h‐gas1 mRNA (a marker of G0 phase) and histone H3 (a marker of S phase). Clusterin mRNA accumulation progressively increased in cells proceeding to confluence after seeding and to quiescence upon serum starvation, and peaked at around G0, in parallel with h‐gas1 mRNA. At 6 h (roughly G1 phase) clusterin transcript formed a second peak, followed by a gradual decrease until 36 h. Correspondence of clusterin protein accumulation to its mRNA occurred solely with regard to the G0 peak but not to the second one. The possible meaning of the cell cycle related clusterin gene expression is discussed.
Activation of channel activity of the NMDA receptor‐PSD‐95 complex by guanylate kinase‐associated protein (GKAP)
Authors: Yamada Yasue , Chochi Yasuyo , Ko Ji-Ae , Sobue Kenji , Inui Makoto
Published: July 2002

The channel‐associated protein PSD‐95 functionally modulates NMDA receptor channels, interacting with the channels via PDZ domain of PSD‐95. PSD‐95 also interacts with guanylate kinase‐associated protein (GKAP) through the guanylate kinase‐like domain of PSD‐95. Here we report that GKAP markedly potentiates the channel activity of the receptor‐PSD‐95 complex. However, GKAP had no effect on basic properties of the channels nor on PSD‐95‐induced changes in channel properties. Thus, GKAP affects the channel activity of the NMDA receptor via PSD‐95 quantitatively, which may make signal transmission more efficient at postsynaptic sites.
Cationic silanes stabilize intermediates in DNA condensation
Authors: Fang Ye , Hoh Jan H
Published: July 2002

In vitro condensation of DNA has been widely studied to gain insight into the mechanisms of DNA compaction in biological systems such as chromosomes and phage heads and has been used to produce nanostructured particles with novel material and functional properties. Here we report on the condensation of DNA in aqueous solutions by cationic silanes, which combine the condensing properties of polyamines with the cross‐linking chemistry of silanes. DNA can be reversibly condensed into classical toroidal and rod‐shaped structures with these agents. At low silane concentrations DNA forms a variety of looped structures with well‐defined characteristics, including flower‐ and sausage‐shaped forms. These structures suggest that at low silane concentrations a DNA‐DNA contact in which the strands are at very large angles to each other is stabilized. Changes in these structures observed as a function of silane concentration suggest possible pathways for the formation of toroids and rods.
Catalytic subunit of telomerase expression is related to RNA component expression
Authors: Stanta Giorgio , Bonin Serena , Niccolini Benedetta , Raccanelli Anna , Baralle Francisco
Published: July 2002

Telomere length is maintained by the ribonucleoprotein enzyme telomerase. The RNA component of telomerase (hTR) is widespread, and only the expression of the mRNA encoding the catalytic protein subunit (hTRT) is correlated with telomerase activity. We have studied the level of expression of hTR and hTRT in four different models of neoplastic and preneoplastic lesions using the RT‐PCR method on RNA extracted from paraffin‐embedded human tissues after microdissection. The expression at the mRNA level was compared with the enzymatic activity. Our results suggest that there may be a reciprocal control at the transcriptional level of the expression of hTRT and hTR which in turn is associated with tumor progression.
Thermotolerance and cell death are distinct cellular responses to stress: dependence on heat shock proteins
Authors: Samali Afshin , Holmberg Carina I. , Sistonen Lea , Orrenius Sten
Published: July 2002

We tested the hypothesis that heat shock protein (Hsp) induction and cell death are mutually exclusive responses to stress. Despite activation of heat shock transcription factor 1 at temperatures ranging from 40 to 46°C, Hsp72 and Hsp27 were not induced above 42°C. Moreover, cells underwent apoptosis at 44°C and necrosis at 46°C, with mitochondrial cytochrome c release at both temperatures. However, only apoptosis was associated with caspase activation. Treatment of cells with z‐VAD‐fmk prior to heat shock at 44°C failed to restore Hsp induction despite inhibition of heat‐induced apoptosis. Furthermore, accumulation of Hsps after incubation at 42°C rendered the cells resistant to apoptosis. These results suggest that lack of Hsp induction is the cause rather than the consequence of cell death.
Color Doppler ultrasound, pregnancy‐induced hypertension and small‐for‐gestational‐age fetuses
Authors: Hung J.H. , Ng H.T. , Pan Y.P. , Yang M.J. , Shu L.P.
Published: July 2002

Objective: The nomogram of blood velocity flow resistance of the spiral arteries was built at 13–25 gestational weeks. Thereafter, by using the nomogram we tried to assess the results of the color Doppler examination of the uteroplacental circulation at the second trimester to predict pregnancy‐induced hypertension (PIH) and small‐for‐gestational‐age (SGA). Methods: Two groups of patients were studied. Group 1, for the establishment of the nomogram, included 175 uncomplicated pregnancies with gestational ages ranging from 13–25 weeks. The Doppler flow waveforms of the spiral arteries were measured once for each pregnancy in the studies. Group 2 consisted of 305 singletons selected consecutively for prospective study to confirm the occurrence of PIH or SGA. They were scanned twice for the measurements of the spiral artery waveforms at 13–19 and 20–25 weeks, respectively to test which gestational weeks interval in the nomogram is most sensitive in predicting PIH and SGA. Results: The 5th, 50th and 95th percentiles of the pulsatility index (PI) values of the nomogram at the second trimester were used as the cut‐off points to predict pregnancies complicated with SGA or PIH at delivery. Using the receiver operator curve, the 50th percentiles of the PI values of the nomograms were chosen as predictives for the development of PIH and SGA. At 13–19 gestational weeks, the specificities in predicting PIH and SGA were 50.71% and 49.82%, respectively, and the sensitivities were 52.00% and 50.00%, respectively. The calculated Cohen's Kappa statistics were 0.008 and 0.001, respectively in predicting PIH and SGA. At 20–25 gestational weeks, the specificities in predicting PIH and SGA were 49.64% and 49.46%, respectively, and the sensitivities were 56.00% and 57.14%, respectively. The calculated Cohen's Kappa statistics were 0.017 and 0.022, respectively in predicting PIH and SGA. Conclusion: The measurements of uteroplacental blood flow velocity waveforms at the second trimester are not sensitive enough to be an early screening tool for PIH and SGA in the low risk, non‐selected pregnancy population. The fact suggests that in most gravidas complicated with PIH and SGA, the physiological process of trophoblastic invasion in the spiral artery was not prevented before the 25th gestational week.
Total productive maintenance: a contextual view
Authors: McKone Kathleen E. , Schroeder Roger G. , Cua Kristy O.
Published: July 2002

While Total Productive Maintenance (TPM) has been promoted for its simplicity and its benefits to the maintenance delivery system, both the academic and practitioner literature has failed to identify the contextual issues that influence TPM adoption. This paper explores the contextual differences of plants to better understand what types of companies have adopted TPM programs. We propose a theoretical framework for understanding the use of TPM and how it depends on managerial factors such as Just‐in‐Time (JIT), Total Quality Management (TQM) and Employee Involvement (EI) as well as environmental and organizational factors such as country, industry and company characteristics. We test this framework using data from 97 plants in three different countries to determine what types of companies are most likely to aggressively pursue TPM practices. We find that specific contextual variables explain a significant portion of the variance in the level of TPM implementation. Our results indicate that while environmental contextual factors, such as country, help to explain differences in TPM implementation, managerial contextual factors, which are under the direction of plant management, are more important to the execution of TPM programs. We discuss environmental, organizational and managerial issues that should be considered when developing or improving maintenance systems.
International operations management research
Authors: Prasad Sameer , Babbar Sunil
Published: July 2002

This paper profiles the literature on international operations management (IOM) from 28 leading operations management, international business, and management journals over the years 1986–1997. Trends in the frequency of IOM articles published and in topical coverage are identified based on research appearing in the journal set reviewed. A framework is developed and presented for classifying the IOM research literature by topical area and scope. Based on the articles reviewed, IOM research is found to focus most on industrialized countries and regions. There is need for empirical studies that span a wider range of countries in order to glean broader insights and to develop generalized theories of international operations management. A number of issues are identified for possible future research. The IOM literature from the journal set is reviewed and the comprehensive set of bibliographic references included provides both academicians and practitioners with a useful source of information to draw from. As identified, much of the work in international operations management seems motivated by a desire to provide firms with an economic benefit. While this is undoubtedly worthwhile, the objective of IOM research could be broadened to encompass social and economic goals of non‐profit organizations as well as international agencies such as the United Nations.
Phenylalanine and phenylpyruvate inhibit ATP diphosphohydrolase from rat brain cortex
Authors: Berti Simone Luisa , Bonan Carla Denise , da Silva Flávio Laporta , Battastini Ana Maria Oliveira , Sarkis João José Freitas , Wannmacher Clóvis Milton Duval
Published: July 2002

The main objective of the present study was to characterize the inhibition by phenylalanine and phenylpyruvate of ATP diphosphohydrolase activity in synaptosomes from the brain cortex of rats. This enzyme participates together with a 5′‐nucleotidase in adenosine formation from the neurotransmitter, ATP, in the synaptic cleft. The inhibition of ATP diphosphohydrolase was competitive for nucleotide hydrolysis but 5′‐nucleotidase was not affected by these metabolites. Furthermore, the two substances inhibited enzyme activity by acting at the same binding site. If the enzyme inhibition observed in vitro also occurs in the brain of PKU patients, it may promote an increase in ATP levels in the synaptic cleft. In this case, the neurotoxicity of ATP could possibly be one of the mechanisms leading to the characteristic brain damage of phenylketonuria.
Olfactory epithelial organotypic slice cultures: A useful tool for investigating olfactory neural development
Authors: Gong Qizhi , Liu Wei‐Lin , Srodon Monica , Foster Tanya D. , Shipley Michael T.
Published: July 2002

Anin vitro slice culture was established for investigating olfactory neural development. The olfactory epithelium was dissected from embryonic day 13 rats; 400μm slices were cultured for 5 days in serum‐free medium on Millicell‐CM membranes coated with different substrates. The slices were grown in the absence of their appropriate target, the olfactory bulb, or CNS derived glia. The cultures mimic many features ofin vivo development. Cells in the olfactory epithelium slices differentiate into neurons that express olfactory marker protein (OMP). OMP‐positive cells have the characteristic morphology of olfactory receptor neurons: a short dendrite and a single thin axon. The slices support robust axon outgrowth. In single‐label experiments, many axons expressed neural specific tubulin, growth‐associated protein 43 and OMP. Axons appeared to grow equally well on membranes coated with type I rat tail collagen, laminin or fibronectin. The cultures exhibit organotypic polarity with an apical side rich in olfactory neurons and a basal side supporting axon outgrowth. Numerous cells migrate out of the slices, of which a small minority was identified as neurons based on the expression of neural specific tubulin and HuD, a nuclear antigen, expressed exclusively in differentiated neurons. Most of the migrating cells, however, were positive for glial fibrilary acidic protein and S‐100, indicating that they are differentiated glia. A subpopulation of these glial cells also expressed low‐affinity nerve growth factor receptors, indicating that they are olfactory Schwann cells. Both migrating neurons and glia were frequently associated with axons growing out of the slice. In some cases, axons extended in advance of migrating cells. This suggests that olfactory receptor neurons in organotypic cultures require neither a pre‐established glial/neuronal cellular terrain nor any target tissue for successful axon outgrowth. Organotypic olfactory epithelial slice cultures may be useful for investigating cellular and molecular mechanisms that regulate early olfactory development and function.
Morphological, biochemical and behaviouralchanges induced by neurotoxic and inflammatory insultsto the nucleus basalis
Authors: Casamenti Fiorella , Prosperi Costanza , Scali Carla , Giovannelli Lisa , Pepeu Giancarlo
Published: July 2002

Interest in the basal forebrain cholinergic system has greatly increased sinceneuropathological studies in humans provided evidence that this system is severely affected in Alzheimer's disease and other dementing disorders. In laboratory animals, disruption of the nucleusbasalis cholinergic neurones has been produced by several neurotoxic insults in order to obtain amodel reproducing the behavioural impairment related to the cholinergic deficits.

The experiments reported in this review demonstrate that excitotoxic amino acids, β‐amyloid and lipopolysaccharide, injected directly in the nucleus basalis are toxic to thecholinergic neurones in the rat. The excitotoxin lesions of the nucleus basalis, although notselective, are a useful tool for producing experimental animals with cholinergic hypofunction andfor investigating drugs able to ameliorate the cholinergic functions. Local injections of amyloidpeptides in the rat nucleus basalis produced cholinergic hypofunction and some behaviouralimpairment. Finally, an intense glia reaction with a limited cholinergic hypofunction and nobehavioural impairment was induced by a 4‐week infusion of lipopolysaccharide in the nucleusbasalis.

In conclusion, all three models, in spite of their limitations, offer useful tools for the studyof the pathogenetic mechanisms of Alzheimers disease and for investigating potentially usefuldrugs.
Association between cell swelling and glycogen content in cultured astrocytes
Authors: Dombro Roy S. , Bender Alex S. , Norenberg Michael D.
Published: July 2002

Treatment of cultured rat astrocytes with hypotonic media or with 1 mM glutamate for 90 min caused cell swelling and a significant increase in glycogen content. Conversely, treatment with hypertonic media caused cell shrinkage with a corresponding decrease in astrocyte glycogen, which was proportional to the increasing osmolality of the hypertonic media. The glutamate receptor antagonist, MK‐801, lowered both the glutamate‐induced swelling and glycogen increase. These findings demonstrate a correlation between changes in cell volume and astrocyte glycogen content. This may explain the increased astrocytic glycogen observed in many neuropathological conditions where astrocyte swelling occurs. Because glycogen represents the largest energy reserve in the central nervous system, a swelling‐induced disturbance in glycogen metabolism may lead to abnormal glial‐neuronal interactions resulting in impaired brain bioenergetics.
Relationships between attempted suicide, temperamental vulnerability, and violent criminality in a Swedish forensic psychiatric population
Authors: Gunilla Stålenheim E.
Published: July 2002

The relationship between suicide attempts and different vulnerability factors was investigated in 61 male subjects during forensic psychiatric examination. Personality traits and psychopathy were determined by means of the Karolinska Scales of Personality (KSP) and the Psychopathy Checklist-Revised (PCL-R). Clinical diagnoses were determined by the use of Structured Clinical Interview for DSM-III-R (SCID). Platelet monoamine oxidase (MAO) activity was investigated in 58 subjects.

Suicide attempters had extremely low socialization and high impulsive aggression. This was independent of a history of repeatedly criminal violence or not. They had higher PCL-R scores and lower levels of platelet MAO activity than non-attempters. No relationship was found between suicide attempts and repeated violent criminality. However, among the subjects with repeated criminal violence there was a highly significant difference between suicide attempters and non-attempters, indicating different personality profiles in violent offenders with and without suicidal behavior. Suicidal behavior was significantly associated with borderline personality disorder, but not with any other single DSM-III-R disorder. The results show a far more severe personality disturbance in suicide attempters than in other violent patients in this type of population. Suicidal behavior should therefore be evaluated and treated per se.
Twenty‐Four Hour Activity and Sleep Profiles for Adults Living with Arthritis: Habits Matter
Authors: Feehan Lynne M. , Lu Na , Xie Hui , Li Linda C.
Published: October 2020

Objective

To identify 24‐hour activity–sleep profiles in adults with arthritis and explore factors associated with profile membership.

Methods

Our study comprised a cross‐sectional cohort and used baseline data from 2 randomized trials studying activity counseling for people with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), or knee osteoarthritis (OA). Participants wore activity monitors for 1 week and completed surveys for demographic information, mood (Patient Health Questionnaire 9), and sitting and walking habits (Self‐Reported Habit Index). A total of 1,440 minutes/day were stratified into minutes off body (activity unknown), sleeping, resting, nonambulatory, and intermittent or purposeful ambulation. Latent class analysis determined cluster numbers; baseline‐category multinomial logit regression identified factors associated with cluster membership.

Results

Our cohort included 172 individuals, including 51% with RA, 30% with OA, and 19% with SLE. We identified 4 activity–sleep profiles (clusters) that were characterized primarily by differences in time in nonambulatory activity: high sitters (6.9 hours sleep, 1.6 hours rest, 13.2 hours nonambulatory activity, and 1.6 hours intermittent and 0.3 hours purposeful walking), low sleepers (6.5 hours sleep, 1.2 hours rest, 12.2 hours nonambulatory activity, and 3.3 hours intermittent and 0.6 hours purposeful walking), high sleepers (8.4 hours sleep, 1.9 hours rest, 10.4 hours nonambulatory activity, and 2.5 hours intermittent and 0.3 hours purposeful walking), and balanced activity (7.4 hours sleep, 1.5 hours sleep, 9.4 hours nonambulatory activity, and 4.4 hours intermittent and 0.8 hours purposeful walking). Younger age (odds ratio [OR] 0.95 [95% confidence interval (95% CI) 0.91–0.99]), weaker occupational sitting habit (OR 0.55 [95% CI 0.41–0.76]), and stronger walking outside habit (OR 1.43 [95% CI 1.06–1.91]) were each associated with balanced activity relative to high sitters.

Conclusion

Meaningful subgroups were identified based on 24‐hour activity–sleep patterns. Tailoring interventions based on 24‐hour activity–sleep profiles may be indicated, particularly in adults with stronger habitual sitting or weaker walking behaviors.
Addressing Health Literacy Needs in Rheumatology: Which Patient Health Literacy Profiles Need the Attention of Health Professionals?
Authors: Bakker Mark M. , Putrik Polina , Rademakers Jany , van de Laar Mart , Vonkeman Harald , Kok Marc R. , Voorneveld‐Nieuwenhuis Hanneke , Ramiro Sofia , de Wit Maarten , Buchbinder Rachelle , Batterham Roy , Osborne Richard H. , Boonen Annelies
Published: October 2020

Objective

To identify and describe health literacy profiles of patients with rheumatic diseases and explore whether the identified health literacy profiles can be generalized to a broader rheumatology context.

Methods

Patients with rheumatoid arthritis, spondyloarthritis, and gout from 3 hospitals in different regions in The Netherlands completed the Health Literacy Questionnaire (HLQ). Hierarchical cluster analysis was used to identify patients’ health literacy profiles based on 9 HLQ domains. A multinomial regression model with the identified health literacy profiles as the dependent variable was fitted to assess whether patients with a given disease type or attending a given hospital were more likely to belong to a specific profile.

Results

Among 895 participating patients, the lowest mean HLQ domain scores (indicating most difficulty) were found for “critical appraisal,” “navigating the health system,” and “finding good health information.” The 10 identified profiles revealed substantial diversity in combinations of strengths and weaknesses. While 42% of patients scored moderate to high on all 9 domains (profiles 1 and 3), another 42% of patients (profiles 2, 4, 5, and 6) clearly struggled with 1 or several aspects of health literacy. Notably, 16% (profiles 7–10) exhibited difficulty across a majority of health literacy domains. The probability of belonging to one of the profiles was independent of the hospital where the patient was treated or the type of rheumatic disease.

Conclusion

Ten distinct health literacy profiles were identified among patients with rheumatic diseases, independent of disease type and treating hospital. These profiles can be used to facilitate the development of health literacy interventions in rheumatology.
NbIr2B2 and TaIr2B2 – New Low Symmetry Noncentrosymmetric Superconductors with Strong Spin–Orbit Coupling
Authors: Górnicka Karolina , Gui Xin , Wiendlocha Bartlomiej , Nguyen Loi T. , Xie Weiwei , Cava Robert J. , Klimczuk Tomasz
Published: October 2020

Superconductivity was first observed more than a century ago, but the search for new superconducting materials remains a challenge. The Cooper pairs in superconductors are ideal embodiments of quantum entanglement. Thus, novel superconductors can be critical for both learning about electronic systems in condensed matter and for possible application in future quantum technologies. Here two previously unreported materials, NbIr2B2 and TaIr2B2, are presented with superconducting transitions at 7.2 and 5.2 K, respectively. They display a unique noncentrosymmetric crystal structure, and for both compounds the magnetic field that destroys the superconductivity at 0 K exceeds one of the fundamental characteristics of conventional superconductors (the “Pauli limit”), suggesting that the superconductivity may be unconventional. Supporting this experimentally based deduction, first‐principle calculations show a spin‐split Fermi surface due to the presence of strong spin–orbit coupling. These materials may thus provide an excellent platform for the study of unconventional superconductivity in intermetallic compounds.
Scalable Functionalization of Optical Fibers Using Atomically Thin Semiconductors
Authors: Ngo Gia Quyet , George Antony , Schock Robin Tristan Klaus , Tuniz Alessandro , Najafidehaghani Emad , Gan Ziyang , Geib Nils C. , Bucher Tobias , Knopf Heiko , Saravi Sina , Neumann Christof , Lühder Tilman , Schartner Erik P. , Warren‐Smith Stephen C. , Ebendorff‐Heidepriem Heike , Pertsch Thomas , Schmidt Markus A. , Turchanin Andrey , Eilenberger Falk
Published: October 2020

Atomically thin transition metal dichalcogenides are highly promising for integrated optoelectronic and photonic systems due to their exciton‐driven linear and nonlinear interactions with light. Integrating them into optical fibers yields novel opportunities in optical communication, remote sensing, and all‐fiber optoelectronics. However, the scalable and reproducible deposition of high‐quality monolayers on optical fibers is a challenge. Here, the chemical vapor deposition of monolayer MoS2 and WS2 crystals on the core of microstructured exposed‐core optical fibers and their interaction with the fibers’ guided modes are reported. Two distinct application possibilities of 2D‐functionalized waveguides to exemplify their potential are demonstrated. First, the excitonic 2D material photoluminescence is simultaneously excited and collected with the fiber modes, opening a novel route to remote sensing. Then it is shown that third‐harmonic generation is modified by the highly localized nonlinear polarization of the monolayers, yielding a new avenue to tailor nonlinear optical processes in fibers. It is anticipated that the results may lead to significant advances in optical‐fiber‐based technologies.
Visualization of Shallow‐Groove Expansion of Au(111) Facet under Methane Pyrolysis
Authors: Li Xiang , Shen Yongli , Ge Mengke , Deng Ziliang , Yuan Wenjuan , Xi Wei , Luo Jun
Published: October 2020

Metallic catalyst facets are considered pivotal in determining the activity and selectivity of heterogeneous catalysis. However, the characterization of the dynamic evolution of metallic catalyst facets remains unsatisfactory, and the identification of evolved facets relies upon phenomenological criteria. Here, to understand the functional mechanism of catalyst facet formation, the dynamic evolution of the Au(111) facet is investigated by in situ transmission electron microscopy during methane pyrolysis. A shallow groove of a few atoms in depth is formed and expanded on the Au(111) facet. Density functional theory results show that the adsorption of carbon weakens the AuAu bonds, facilitating Au atom removal from the surface. Finally, a new flat Au(111) facet is formed. Thus, the facets undergo dynamic evolution during the actual pyrolytic reaction. This research may promote understanding of the catalytic mechanism and guide the design of the next generation of highly efficient catalysts.
Multi‐Level Electro‐Thermal Switching of Optical Phase‐Change Materials Using Graphene
Authors: Ríos Carlos , Zhang Yifei , Shalaginov Mikhail Y. , Deckoff-Jones Skylar , Wang Haozhe , An Sensong , Zhang Hualiang , Kang Myungkoo , Richardson Kathleen A. , Roberts Christopher , Chou Jeffrey B. , Liberman Vladimir , Vitale Steven A. , Kong Jing , Gu Tian , Hu Juejun
Published: October 2020

Reconfigurable photonic systems featuring minimal power consumption are crucial for integrated optical devices in real‐world technology. Current active devices available in foundries, however, use volatile methods to modulate light, requiring a constant supply of power and significant form factors. Essential aspects to overcome these issues are the development of nonvolatile optical reconfiguration techniques which are compatible with on‐chip integration with different photonic platforms and do not disrupt their optical performances. Herein, a solution is demonstrated using an optoelectronic framework for nonvolatile tunable photonics that uses undoped‐graphene microheaters to thermally and reversibly switch the optical phase‐change material Ge2Sb2Se4Te1 (GSST). An in situ Raman spectroscopy method is utilized to demonstrate, in real‐time, reversible switching between four different levels of crystallinity. Moreover, a 3D computational model is developed to precisely interpret the switching characteristics, and to quantify the impact of current saturation on power dissipation, thermal diffusion, and switching speed. This model is used to inform the design of nonvolatile active photonic devices; namely, broadband Si3N4 integrated photonic circuits with small form‐factor modulators and reconfigurable metasurfaces displaying 2π phase coverage through neural‐network‐designed GSST meta‐atoms. This framework will enable scalable, low‐loss nonvolatile applications across a diverse range of photonics platforms.
Gold‐Catalyzed Oxidative Cross‐Coupling Reactions among Two Distinct Arenes and One Gold Carbene with Phosphoric Acids as Cocatalysts
Authors: Patil Manoj D. , Kale Balaji S. , Liu Rai‐Shung
Published: October 2020

Gold‐catalyzed oxidative cross‐coupling reactions of two distinct arenes with one gold carbene furnish triarylmethane products. Notably, competitive homo‐coupling reactions are efficiently suppressed with a phosphoric acid as co‐catalyst (10 mol%) in THF. These cross‐coupling reactions have a wide scope of applicable substrates, with respect to indoles, arylamines, and α‐aryl diazo cyanides or esters. Our mechanistic analysis indicates that the basicity of the arylanilines greatly affects the cross‐coupling efficiency.

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