Ecological orientations to sociolinguistic scale: Insights from study abroad experiences

The sociolinguistics of globalisation, as an emerging paradigm, focuses on the impact of mobility on the linguistic capital of mobile individuals. To understand this, Blommaert advocates a scalar approach to language arguing that some people’s repertoires “will allow mobility while others will not” (2010. The sociolinguistics of globalization. Cambridge: Cambridge University Press: 23) and proposing high scale, low scale orderings. In this paper we introduce an ecological orientation to sociolinguistic scale that challenges the fixity of a high/low scale distinction by conceptually drawing on the notions of flat ontology (Marston et al. 2005. Human geography without scale. Transactions of the Institute of British Geographers 30(4). 416–432) and exchange value (Heller. 2010. The commodification of language. Annual Review of Anthropology 39. 101–114). We do this in relation to Study Abroad (SA) contexts, which offer spaces for investigating how mobility influences the exchange value of individuals’ linguistic repertoires. The study speaks to a broader project in social research which emphasises the agency, subjectivity and criticality of the individual and stresses the complex and rhizomatic nature of social interaction. Drawing on moment analysis (Li. 2011. Moment Analysis and translanguaging space: Discursive construction of identities by multilingual Chinese youth in Britain. Journal of Pragmatics 43. 1222–1235), we examine the experiences of two study abroad students in the UK. These include tellings of critical and reflective moments through which we interpret their experience of how the interplay of language, place and ecology of interaction results in constant, dynamic changes in the exchange value of their English repertoires. Our contribution is to show how an ecological orientation and a flat, rather than stratified, ontology enables insights into language use and globalisation in a way that empowers multilingual, mobile individuals

Effect of protonation state and N-acetylation of chitosan on its interaction with xanthan gum: a molecular dynamics simulation study

Hydrophilic matrices composed of chitosan (CS) and xanthan gum (XG) complexes are of pharmaceutical interest in relation to drug delivery due to their ability to control the release of active ingredients. Molecular dynamics simulations (MDs) have been performed in order to obtain information pertaining to the effect of the state of protonation and degree of N-acetylation (DA) on the molecular conformation of chitosan and its ability to interact with xanthan gum in aqueous solutions. The conformational flexibility of CS was found to be highly dependent on its state of protonation. Upon complexation with XG, a substantial restriction in free rotation around the glycosidic bond was noticed in protonated CS dimers regardless of their DA, whereas deprotonated molecules preserved their free mobility. Calculated values for the free energy of binding between CS and XG revealed the dominant contribution of electrostatic forces on the formation of complexes and that the most stable complexes were formed when CS was at least half-protonated and the DA was ≤50%. The results obtained provide an insight into the main factors governing the interaction between CS and XG, such that they can be manipulated accordingly to produce complexes with the desired controlled-release effect

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

Comparative analysis of co-processed starches prepared by three different methods

Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient

Ultra-high resolution X-ray structures of two forms of human recombinant insulin at 100 K

The crystal structure of a commercially available form of human recombinant (HR) insulin, Insugen (I), used in the treatment of diabetes has been determined to 0.92 Å resolution using low temperature, 100 K, synchrotron X-ray data collected at 16,000 keV (λ = 0.77 Å). Refinement carried out with anisotropic displacement parameters, removal of main-chain stereochemical restraints, inclusion of H atoms in calculated positions, and 220 water molecules, converged to a final value of R = 0.1112 and Rfree = 0.1466. The structure includes what is thought to be an ordered propanol molecule (POL) only in chain D(4) and a solvated acetate molecule (ACT) coordinated to the Zn atom only in chain B(2). Possible origins and consequences of the propanol and acetate molecules are discussed. Three types of amino acid representation in the electron density are examined in detail: (i) sharp with very clearly resolved features; (ii) well resolved but clearly divided into two conformations which are well behaved in the refinement, both having high quality geometry; (iii) poor density and difficult or impossible to model. An example of type (ii) is observed for the intra-chain disulphide bridge in chain C(3) between Sγ6–Sγ11 which has two clear conformations with relative refined occupancies of 0.8 and 0.2, respectively. In contrast the corresponding S–S bridge in chain A(1) shows one clearly defined conformation. A molecular dynamics study has provided a rational explanation of this difference between chains A and C. More generally, differences in the electron density features between corresponding residues in chains A and C and chains B and D is a common observation in the Insugen (I) structure and these effects are discussed in detail. The crystal structure, also at 0.92 Å and 100 K, of a second commercially available form of human recombinant insulin, Intergen (II), deposited in the Protein Data Bank as 3W7Y which remains otherwise unpublished is compared here with the Insugen (I) structure. In the Intergen (II) structure there is no solvated propanol or acetate molecule. The electron density of Intergen (II), however, does also exhibit the three types of amino acid representations as in Insugen (I). These effects do not necessarily correspond between chains A and C or chains B and D in Intergen (II), or between corresponding residues in Insugen (I). The results of this comparison are reported

An Unusual Case of Parasitic Constrictive Pericarditis

Parasitic constrictive pericarditis is a rare entity. We present a case of a 75-year-old man who presented with dyspnea, ascites, and pedal edema and was found to have constrictive pericarditis on multimodality imaging with positive serology for Strongyloides Stercoralis. Treatment required ivermectin and radical pericardiectomy with significant clinical improvement. (Level of Difficulty: Intermediate.

Evaluation of alginate compressed matrices as prolonged drug delivery systems

This research investigated the use of sodium alginate for the preparation of hydrophylic matrix tablets intended for prolonged drug release using ketoprofen as a model drug. The matrix tablets were prepared by direct compression using sodium alginate, calcium gluconate, and hydroxypropylmethylcellulose (HPMC) in different combinations and ratios. In vitro release tests and erosion studies of the matrix tablets were carried out in USP phosphate buffer (pH 7.4). Matrices consisting of sodium alginate alone or in combination with 10% and 20% of HPMC give a prolonged drug release at a fairly constant rate. Incorporation of different ratios of calcium gluconate leads to an enhancement of the release rate from the matrices and to the loss of the constant release rate of the drug. Only the matrices containing the highest quantity of HPMC (20%) maintained their capacity to release ketoprofen for a prolonged time