Properties of poly(ethylene terephthalate)–poly(ethylene naphthalene 2,6‐dicarboxylate) blends with montmorillonite clay

The production and properties of blends of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalene 2,6‐dicarboxylate) (PEN) with three modified clays are reported. Octadecylammonium chloride and maleic anhydride (MAH) are used to modify the surface of the montmorillonite–Na⁺ clay particles (clay–Na⁺) to produce clay–C18 and clay–MAH, respectively, before they are mixed with the PET/PEN system. The transesterification degree, hydrophobicity and the effect of the clays on the mechanical, rheological and thermal properties are analysed. The PET–PEN/clay–C18 system does not show any improvements in the mechanical properties, which is attributed to poor exfoliation. On the other hand, in the PET–PEN/clay–MAH blends, the modified clay restricts crystallization of the matrix, as evidenced in the low value of the crystallization enthalpy. The process‐induced PET–PEN transesterification reaction is affected by the clay particles. Clay–C18 induces the largest proportion of naphthalate–ethylene–terephthalate (NET) blocks, as opposed to clay–Na⁺ which renders the lowest proportion. The clay readily incorporates in the bulk polymer, but receding contact‐angle measurements reveal a small influence of the particles on the surface properties of the sample. The clay–Na⁺ blend shows a predominant solid‐like behaviour, as evidenced by the magnitude of the storage modulus in the low‐frequency range, which reflects a high entanglement density and a substantial degree of polymer–particle interactions. Copyright © 2005 Society of Chemical Industry     

Development of early expressive and communicative action: Reinterpreting the evidence from a dynamic systems perspective.

A systems approach is introduced and applied to the development of expressive and communicative action of infants in the first year of life. In this approach, expressive and communicative actions are organized, as part of cooperative systems with other elements of the infants' physiology, cognition, behavior, and social environment. A systems approach presumes that order arises dynamically as a result of the interaction between the cooperating elements that are changing asynchronously, rather than as the result of centrally coordinated developmental change that is synchronous across domains. The systems approach further assumes that the control parameter responsible for eliciting developmental change may be different depending on age, context, and task. It offers a means to understand previously unexplained developmental phenomena: the appearance of mature forms of expression before mature functon has been achieved, the asynchronous rates of development of communicative-action components, discontinuous developmental shifts arising from continuous processes, and the process by which adults influence communicative development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A role for Edman degradation in proteome studies

Advances in protein database design and the software used to access the sequence data has led to progress in using protein attributes such as amino acid composition and peptide masses to identify proteins separated by two-dimensional electrophoresis. However, Edman degradation remains the principal technique for protein identification and it presents a significant bottleneck in the progress towards rapid protein identification. Simple modifications to the sequencing hardware, which automate the delivery of protein spots into the sequencer, and parallel sequencing of the protein spots represent a significant advance in the use of Edman degradation to rapidly generate the powerful protein attribute, an N-terminal sequence tag.     

Protein expression profiles in human breast ductal carcinoma and histologically normal tissue

Reference two-dimensional (2-D) gels are presented for human breast ductal carcinoma and histologically normal tissue. Whole biopsy fragments were analyzed, including epithelial and nonepithelial components. Thirty-five spots have been assigned by gel matching to the human liver SWISS-2DPAGE reference map and/or to the human primary keratinocyte IPG map from the Danish Center for Human Genome. N-terminal microsequencing was applied to confirm randomly chosen matching assignments and to identify six new spots. Protein expression profiles in ductal carcinoma and in normal breast tissue appeared to be similar, except for a pattern consisting of 32 spots, which were highly expressed in all carcinoma specimens, and less intense and occasionally undetectable in normal tissue. This difference was statistically significant. Assignment has been obtained for several spots, namely GRP94, GRP78, GRP75, mitochondrial HSP60, calreticulin, protein disulfide isomerase, peptidyl-prolyl cis-trans isomerase, collagen-binding protein 2, fructose bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, thioredoxin, cytochrome c oxidase VA subunit, tubulin beta isoform and macrophage migration inhibitory factor (MIF). The cancer- and tissue-specificity of the described pattern was assessed by matching to the Swiss-2DPAGE human liver, hepatoma, lymphoma, erythroleukemia reference maps. The pattern of 32 spots was found to be indicative of epithelial neoplasia.     

New actinide ternary intermetallic compounds: synthesis, characterization and physical properties

Twelve new ternary intermetallic compounds of light actinide elements from Th to Pu, namely U₄Tc₇Si₆, U₄Tc₇Ge₆, Np₄Ru₇Ge₆, U₂Tc₃Si₅, Np₂Re₃Si₅, Pu₂Re₃Si₅, Th₂Mo₃Si₄, U₂Mo₃Si₄, U₂Mo₃Ge₄, Np₂Mo₃Si₄, Np₂Mo₃Ge₄, and Pu₂Mo₃Si₄, were obtained. The structures of these compounds are discussed as well as some preliminary physical property studies. Magnetic susceptibility measurements show that An₂Mo₃(Si or Ge)₄ compounds are paramagnetic at all temperatures studied and that U₄Tc₇Si₆ orders antiferromagnetically around 25 K. Mössbauer spectroscopy on Np₄Ru₇Ge₆ does not show a magnetic splitting down to 4.2 K.     

Clinically significant hearing loss in renal allograft recipients treated with intravenous erythromycin

BACKGROUND: Hearing loss is generally regarded as a rare side effect of erythromycin therapy. However, our own clinical experiences in erythromycin-treated patients led us to suspect that this complication may be more common among renal allograft recipients. The purpose of this study was to evaluate the incidence, predisposing factors, clinical characteristics, and outcomes of erythromycin-induced hearing loss among renal allograft recipients. METHODS: We reviewed medical records of renal transplant patients treated for pneumonia with intravenous erythromycin lactobionate. Patients were evaluated for the occurrence of clinically significant hearing loss (including onset, duration, and reversibility), other signs and symptoms of ototoxicity (vertigo and tinnitus), daily erythromycin dose and duration of treatment, concurrent ototoxic drug therapy, renal and hepatic function, and history of previous otic disease. RESULTS: Eleven (32%) of 34 courses of intravenous erythromycin therapy resulted in hearing loss. The incidence of hearing loss was 53% (eight of 15 courses) in patients treated with 4 g of erythromycin daily compared with 16% (three of 19 courses) among those receiving 2 g/d (P = .05). In addition, courses of erythromycin were longer in those suffering auditory toxicity (9.6 +/- 4.7 days) than in nontoxic patients (5.7 +/- 3.6 days) (P < .05). Hepatic and renal function did not differ between toxic and nontoxic patients. All episodes of erythromycin-induced hearing loss were reversible. CONCLUSIONS: We conclude that clinically significant hearing loss occurs in more than 30% of renal allograft recipients treated for pneumonia with intravenous erythromycin lactobionate. Patients who require prolonged courses of erythromycin and those treated with 4 g/d are at particular risk for the development of auditory toxicity. With prompt recognition and modification of therapy, erythromycin-induced hearing loss appears to be completely reversible.