Molecular dynamics simulation of methane in sodium montmorillonite clay hydrates at elevated pressures and temperatures

Computer simulation has been used to study the structure and dynamics of methane in hydrated sodium montmorillonite clays under conditions encountered in sedimentary basins. Systems containing approximately one, two, three and four molecular layers of water have followed gradients of 150 bar km-1 and 30Kkm-1, to a maximum burial depth of 6 km (900 bar and 460 K). Methane is coordinated to approximately 19 oxygen atoms, of which typically 6 are provided by the clay surface. Only in the three- and four-layer hydrates is methane able to leave the clay surface. Diffusion depends strongly on the porosity (water content) and burial depth: self-diffusion coefficients are in the range 0.12 × 10-9m2s-1 for water and 0.04 × 10−9m2s−1 < D < 8.64 × 10−9m2s−1 for methane. Bearing in mind that porosity decreases with burial depth, it is estimated that maximum diffusion occurs at around 3 km. This is in good agreement with the known location of methane reservoirs in sedimentary basins.

The use of sodium carboxymethylcellulose in the preparation of spray-dried proteins for pulmonary drug delivery

The use of sodium carboxymethylcellulose (NaCMC) as a spray-drying excipient in the preparation of inhalable formulations of proteins was investigated, using alkaline phosphatase as a model functional protein. Two spray-dried powders were investigated: a control powder comprising 100% (w/w) alkaline phosphatase and a test powder comprising 67% (w/w) NaCMC and 33% (w/w) alkaline phosphatase. Following physicochemical characterisation, the powders were prepared as both dry powder inhaler (DPI) and pressurised metered dose inhaler (pMDI) formulations. The aerosolisation performance of the formulations was assessed using a Multi-Stage Liquid Impinger, both immediately after preparation and over a 16-week storage period. Formulating the control powder as a DPI resulted in a poor fine particle fraction (FPF: 10%), whereas the FPF of the NaCMC-modified DPI formulation was significantly greater (47%). When the powders were formulated as pMDI systems, the control and NaCMC-modified powders demonstrated FPFs of 52% and 55%, respectively. Following storage, reduced FPF was observed for all formulations except the NaCMC-modified pMDI system; the performance of this formulation following storage was statistically equivalent to that immediately following preparation. Co-spray-drying proteins and peptides with NaCMC may therefore offer an alternative method for the preparation of stable and respirable pMDI formulations for pulmonary delivery. © 2010 Elsevier B.V.

Addition of sodium criterion to SOAR stroke score

Funding The NNUH Stroke and TIA Register is maintained by the NNUH NHS Foundation Trust Stroke Services and data management for this study is supported by the NNUH Research and Development Department through Research Capability Funds.

In vitro antioxidant and immunomodulatory activity of transglutaminase-treated sodium caseinate hydrolysates

Sodium caseinate (NaCN) was incubated prior to and after hydrolysis with a microbial transglutaminase (TGase) and hydrolysed with Prolyve 1000. The resultant hydrolysates were tested for their immunomodulatory and antioxidant activity. TGase-treated hydrolysates significantly reduced (p < 0.05) the production of IL-6 at 0.5 and 1 mg mL−1 and the non-TGase treated hydrolysate reduced the production of IL-6 at 1 mg mL−1 in concanavalin (ConA) stimulated Jurkat T cells. None of the samples had an effect on IL-2. The hydrolysates showed higher oxygen radical absorbance capacity assay and ferric reducing antioxidant power activity than unhydrolysed NaCN, but no significant (p > 0.05) differences were found between the TGase-treated and non-TGase-treated samples. In the presence of hydrogen peroxide, the non-TGase-treated sample exhibited the highest DNA protective effect in U937 cells. These findings suggest that NaCN derived hydrolysates with and without treatment with TGase may exert specific antioxidant, genoprotective and anti-inflammatory effects.

SN 2011A: A low-luminosity interacting transient with a double plateau and strong sodium absorpton

We present optical photometry and spectroscopy of the optical transient SN 2011A. Our data span 140 days after discovery including BVRI u′g′r′i′z′ photometry and 11 epochs of optical spectroscopy. Originally classified as a type IIn supernova (SN IIn) due to the presence of narrow Hα emission, this object shows exceptional characteristics. First, the light curve shows a double plateau, a property only observed before in the impostor SN 1997bs. Second, SN 2011A has a very low luminosity (M_V=-15.72), placing it between normal luminous SNe IIn and SN impostors. Third, SN 2011A shows low velocity and high equivalent width absorption close to the sodium doublet, which increases with time and is most likely of circumstellar origin. This evolution is also accompanied by a change in line profile; when the absorption becomes stronger, a P Cygni profile appears. We discuss SN 2011A in the context of interacting SNe IIn and SN impostors, which appears to confirm the uniqueness of this transient. While we favor an impostor origin for SN 2011A, we highlight the difficulty in differentiating between terminal and non-terminal interacting transients.