2,339 research outputs found

    Novel co-operative magnetic properties of decamethylmanganocenium 2,3-dichloro-5,6-dicyanobenzoquinoneide, 3[Mn(C5Me5)2]:+[DDQ].-

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    Journal ArticleThe electron-transfer salt 3[Mn(C5Me5)2]: + [DDQ].-, isomorphous to orthorhombic [Fe(C5Me5)2].+[DDQ].-, has been prepared. It exhibits a complex field-dependent magnetic phase diagram at low temperatures with evidence for ferromagnetic coupling as well as a low moment state below 4 K for zero-field cooled samples

    Decamethylchromocenium tetracyanoethenide, + [Cr(C5Me5)2]:.+[TCNE].-: a molecular ferromagnet with Tc=3.65 K

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    Journal ArticleThe electron-transfer salt 4[Cr(C5Me5)2] + [TCNE].-(TCNE = tetracyanoethylene) has been prepared and structurally characterized by single-crystal X-ray diffraction. It possesses a solid-state motif of parallel 1D chains of alternating radical cations and anions similar to, but not isostructural to, the ferromagnet [Fe(C5Me5)2].+ [TCNE]. -.4[Cr(C5Me5)2] + [TCNE].- is a soft ferromagnet with no hysteretic effects observed and Tc = 3.65 K

    Herpes Simplex Virus Type 1 Infection Imposes a G1/S Block in Asynchronously Growing Cells and Prevents G1 Entry in Quiescent Cells

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    Herpes simplex virus type 1 (HSV-1) infection disrupted cell cycle regulation in at least two ways. First, infection of quiescent human embryonic lung cells simultaneously with readdition of serum caused inhibition of cyclin D/cyclin-dependent kinase (CDK) 4,6-specific and cyclin E/CDK2-specific phosphorylation of the retinoblastoma protein pRb. The inhibition of cyclin D/CDK4,6 kinase activity corresponded to a loss of cyclin D1 protein and a failure of CDK4 and CDK6 to translocate to the nucleus. Failure to detect cyclin E/CDK2 kinase activity was accompanied by a loss of cyclin E protein and a failure of CDK2 to translocate to the nucleus. Levels of pocket protein p130 persisted, whereas p107 did not accumulate. As a result of these effects on cyclin kinase, G0-infected cells failed to reenter the cell cycle. The second type of HSV-induced cell cycle dysregulation was observed in asynchronously dividing cell cultures. A rapid inhibition of preexisting cyclin E/CDK2 and cyclin A/CDK2 activities was observed in human embryonic lung cells, as well as two other human cell lines: C33 and U2OS. HSV-1 immediate-early gene expression was necessary for the inhibition of CDK2 kinase activity. Cyclin and CDK subunit protein levels, intracellular localization, and complex stability were unaffected by infection. In addition, levels of cyclin-dependent kinase inhibitors, p27 and p21, were not affected by HSV-1. Previous experiments demonstrated that in asynchronous infected cells, hypophosphorylated pRb and pocket protein–E2F complexes accumulated, and cellular DNA synthesis was rapidly inhibited. Coupled with the present results, this indicates that HSV-1 has evolved mechanisms for preventing cells in G1 from proceeding through the restriction point and for cells in S from completing a round of DNA replication

    TOTAL REPLACEMENT OF FISHMEAL WITH AN ORGANICALLY CERTIFIED YEAST–BASED PROTEIN IN PACIFIC WHITE SHRIMP (Litopenaeus Vannamei) DIETS: LABORATORY AND FIELD TRIALS

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    The feasibility of totally replacing the fishmeal component of marine shrimp (Litopenaeus vannamei) diets was examined both in the laboratory setting and during a full–scale commercial trial. Animals were fed either a traditional fishmeal–based diet or one in which complete replacement of fishmeal, on a per protein basis, was manufactured using a yeast–based product, NuPro®. Laboratory studies determined that irrespective of diet fed, no difference in shrimp performance (weight gain, survival and SGR) occurred. A field trial was thus activated to determine whether lab–scale studies were transferable to the commercial setting. Trials were conducted in earthen ponds from mid–June to early November 2005. Ponds were initially stocked with PL12–16 shrimp at a rate of 100,000 per hectare. At trial end, ponds receiving the NuPro®–based feed had equivalent growth to that of shrimp fed the traditional, fishmeal–based diet. Percent increase in weight from initial values and survival for the NuPro® ponds was 296, 269 and 275%, and 78, 76 and 85% respectively, whereas that for the fishmeal–based diet was 305% and 80% respectively. Noteworthy was that within pond size variation of L. vannamei was lower in NuPro® fed animals (±2.3 g) when compared against animals receiving the traditional feed (±4.1 g). Overall observations from the field trial indicate the importance of the »bioreactor« pond with respect to the supply of energy to sustain shrimp growth potential

    Constructing the identity of a nation : the tourist gaze at the Museum of Scotland

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    In an era of global instability and crises of national identity, the role of heritage tourism in creating images of national identity has become an important area for research. This article considers the role of heritage tourism in constructing national identity in the nation of Scotland through the lens of the Museum of Scotland. It describes the findings of qualitative research undertaken with potential and actual target consumers to the Museum of Scotland. Three research questions were addressed: Does the Museum of Scotland construct (1) a vision of a `new\u27 Scotland? (2) a symbol of a `real\u27 Scotland? (3) a collective identity of Scotland? The findings suggest that heritage visitors actively identify through their gaze, constructing multifarious meanings of national identity that are dynamic rather than static.<br /

    Induction by Herpes Simplex Virus of Free and Heteromeric Forms of E2F Transcription Factor

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    We have determined that HSV causes rapid and large increases in cell-cycle-regulated free E2F and S-phase p107/E2F DNA binding activities in asynchronous cultures of C33A cells. Induction occurred by 4 hr postinfection and coincided with the appearance of viral encoded immediate-early and delayed-early proteins, i.e., when viral DNA replication normally commences. No increase in E2F activities occurred when cells were infected with viruses expressing mutant regulatory proteins ICP4 or ICP27, or mutant replication proteins ICP8, pol or helicase, or when cells were infected with wild-type virus in the presence of inhibitors of DNA synthesis. In contrast, ICP8 mutant-infected cells contained elevated amounts of NF kappa B activity equivalent to WT virus, no induction of Sp1 relative to WT virus, and reduced ATF/CREB activity relative to WT virus. Results of transient expression assays with E2F-responsive reporters indicated that the net effect of induction of both active (free E2F) and repressive (p107/E2F) complexes was a decrease in AdE2 promoter activity and an increase in c-myc promoter activity. Taken together these results suggest that HSV can cause unscheduled changes in the amount and functional status of a cell-cycle-regulated transcription factor. These results are discussed in light of possible roles for viral-induced alterations in E2F, especially as related to imposing or overriding cell-cycle checkpoints

    Inhibition of the stress-activated kinase, p38, does not affect the virus transcriptional program of herpes simplex virus type 1

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    To investigate the impact of stress kinase p38 activation on HSV-1 transcription, we performed a global transcript profile analysis of viral mRNA using an oligonucleotide-based DNA microarray. RNA was isolated from Vero cells infected with the KOS strain of HSV-1 in the presence or absence of SB203580, a pyridinyl imidazole inhibitor of p38. Under conditions that eliminated ATF2 activation but had no effect on c-, and reduced virus yield by 85–90%, no effect on accumulation of viral IE, DE, or L transcripts was observed by array analysis or selected Northern blot analysis at 2, 4, and 6 h post infection. Results of array data from cells infected with the ICP27 mutant d27-1 in the presence or absence of SB203580 only reflected the known restricted transcription phenotype of the ICP27 mutant. This result is consistent with a role for p38 activation on virus replication lying downstream of the essential role of ICP27 in DE and perhaps late transcription regulation. No effect of SB203580 on transcription was detected after infection with the ICP0 mutant 7134, at 0.5 or 5.0 PFU/cell, though decreases in the rate of accumulation of all kinetic classes of mRNA could be detected, relative to virus. These results indicate that inhibiting p38 activity in Vero cells, while significantly reducing virus yield, demonstrated no obvious impact on the program of viral transcription
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