Erratum: Development of composites based on recycled polyethylene/sugarcane bagasse fibers

When this article was first published in Polymer Composites, 35:768–774, 2014; DOI: 10.1002/pc.22720 , the lead authors name was incorrectly supplied to the Publisher. His correct name appears above. The authors apologize for any inconvenience this may have caused.     

Aging of ADN Rocket Propellant Formulations with Desmophen®‐Based Elastomer Binder

Desmophen® binder‐based rocket propellant formulations containing ammonium dinitramide (ADN) and different fuel filler types (Al, HMX) were manufactured and investigated. Desmophen® D2220 is a polyesterpolyol. Polyesters are seen as a binder possibility, because of the relatively low temperature of the glass transition region compared to polyether‐based prepolymers such as GAP. The analogous formulations with AP instead of ADN were also included for comparison. The aging was followed by SEM, DSC, and DMA measurements. The accelerated aging program was developed on the principle of thermal equivalent load and the generalized van’t Hoff rule with a scaling factor equal to F=2.9. The aging was performed in air (RH<10 %) at temperature values between 65 and 85 °C and aging times adjusted to a thermal equivalent load of 15 years at 25 °C. DMA measurements of the aged ADN/Desmophen®‐based propellants identified changes in the loss factor curve. In contrast to HTPB‐Al‐AP rocket propellant formulations, the loss factor curve of the ADN formulations with Desmophen®‐based elastomer binder shows only one main apparent peak. The loss factor curves were modeled with exponentially modified Gaussian functions, which have revealed the presence of a second hidden peak. It was found that the aging could be characterized by the time‐temperature dependence of the areas of the hidden peak. The area increased with aging, which is explained by scissioning of the polymer in the shell around the ADN particles. By this process the strength is reduced, which was recognized by the decrease in storage shear modulus.     

Carter's factor calculation using domain transformations and the finite element method

The main purpose of this work is to present a methodology to calculate Carter's factor using the actual air‐gap geometry, that is, without simplifications of the slot geometry. The methodology is based on the finite element method, and its results are compared with some traditional procedures used for Carter's factor calculation and also with a domain transformation technique. It is shown that the finite element method and the domain transformation methodologies present similar results, which are different from the results obtained with traditional procedures. Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of Cu(II) on the complex between kanamycin A and the bacterial ribosomal A site

The solution structure of kanamycin A interacting with a ribosomal A-site fragment was solved by transferred-NOE techniques and found to agree with the structure of the complex observed in the crystal. Despite the fast exchange conditions found for the interaction, the bound form was identified by NOESY spectroscopy. At 600 MHz, NOE effects are only observed for the RNA-associated antibiotic. Dissociation constants were measured by NMR spectroscopy for two sites of interaction (K(d1)=150+/-40 microM; K(d2)=360+/-50 microM). Furthermore, the effects of the Cu(II) ion on the antibiotic, on the RNA fragment that mimics the bacterial ribosomal A site, and on the complex formed between these two entities were analyzed. The study led to the proposal of a model that localizes the copper ion within the kanamycin-RNA complex.     

Combining implicit and explicit techniques to reveal social desirability bias in electricity conservation self-reports

While questionnaires are still the most common way to survey consumers’ behaviors, it is known that respondents’ answers can be affected by the social desirability attributed to the behavior under investigation. To check whether a social desirability bias also affects electricity consumption self-reports, a study was carried out adopting an explicit (questionnaire) and implicit measurement technique (the autobiographical Implicit Association Test). Three behaviors were probed in this way, with a sample of 180 participants (60 for each behavior). The analysis of the congruence between explicit and implicit answers confirms that desirability bias is at stake in self-reported measures of electricity conservation; it also shows that different behaviors—in this same domain—can be subject to this bias to a different extent and that a considerable amount of participants need to be considered as ambivalent. The methodological and conceptual implications of these findings and of the method are discussed with respect to pro-environmental studies and interventions.     

Biodegradation Study of Microcrystalline Chitosan and Microcrystalline Chitosan/β-TCP Complex Composites

Bone repair or regeneration is a common and complicated clinical problem in orthopedic surgery. The importance of natural polymers, such as microcrystalline chitosan, and minerals such as HAp and β-TCP, has grown significantly over the last two decades due to their renewable and biodegradable source, increasing the knowledge and functionality of composites in technological and biomedical applications. This study compares the biodegradation process, bioactivity, structure, morphology, and mechanical properties of microcrystalline chitosan and microcrystalline chitosan/β-TCP complex; the latter according to the new method of preparation. The complex showed a homogeneous network structure with regular pores, good bioactivity, even after 60 days of conducting the hydrolytic and enzymatic degradation process, showing a bacteriostatic and bactericidal activity. The complex indicates that it could be used successfully as a base for implants and scaffolds production in orthopedic surgery.     

Aberrant Expression of Posterior HOX Genes in Well Differentiated Histotypes of Thyroid Cancers

Molecular etiology of thyroid cancers has been widely studied, and several molecular alterations have been identified mainly associated with follicular and papillary histotypes. However, the molecular bases of the complex pathogenesis of thyroid carcinomas remain poorly understood. HOX genes regulate normal embryonic development, cell differentiation and other critical processes in eukaryotic cell life. Several studies have shown that HOX genes play a role in neoplastic transformation of several human tissues. In particular, the genes belonging to HOX paralogous group 13 seem to hold a relevant role in both tumor development and progression. We have identified a significant prognostic role of HOX D13 in pancreatic cancer and we have recently showed the strong and progressive over-expression of HOX C13 in melanoma metastases and deregulation of HOX B13 expression in bladder cancers. In this study we have investigated, by immunohistochemisty and quantitative Real Time PCR, the HOX paralogous group 13 genes/proteins expression in thyroid cancer evolution and progression, also evaluating its ability to discriminate between main histotypes. Our results showed an aberrant expression, both at gene and protein level, of all members belonging to paralogous group 13 (HOX A13, HOX B13, HOX C13 and HOX D13) in adenoma, papillary and follicular thyroid cancers samples. The data suggest a potential role of HOX paralogous group 13 genes in pathogenesis and differential diagnosis of thyroid cancers.