Model-independent measurement of mixing parameters in D0 → K S 0 π+π− decays

The first model-independent measurement of the charm mixing parameters in the decay D 0 → K S 0 π + π − is reported, using a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb−1 at a centre-of-mass energy of 7 TeV. The measured values are x=(−0.86±0.53±0.17)×10−2,y=(+0.03±0.46±0.13)×10−2, x=(−0.86±0.53±0.17)×10−2,y=(+0.03±0.46±0.13)×10−2, where the first uncertainties are statistical and include small contributions due to the external input for the strong phase measured by the CLEO collaboration, and the second uncertainties are systematic

Evaluation of microcrystalline cellulose prepared from sisal fibers as a tablet excipient: A technical note

The above data demonstrated that MCC derived from sisal fibers could be an industrially feasible alternative for currently used MCCs as diluent and disintegrant for both immediate-release as well as sustained-release oral solid dosage forms

Carbon-13 solid state NMR investigation and modeling of the morphological reorganization in regenerated cellulose fibres induced by controlled acid hydrolysis

CPMAS carbon-13 NMR has been used to follow structural changes affecting regenerated cellulose fibres during hydrolysis by mineral acids. The C4 envelope of regenerated cellulose was deconvoluted into separate peaks, for ordered (crystal), part-ordered (surface) and disordered (non-crystal) polymer, which allowed calculation of average crystal lateral sizes, in good agreement with WAXD data. A geometrical model has been used to describe recrystallisation at lateral crystal faces, occurring within a disordered boundary surrounding the crystal interior. A one-dimensional relaxation-diffusion model has also been constructed, appropriate to the spinodal structure of lyocell. This has provided estimates of proton T1ρ relaxation times for pure crystalline (cellulose II) and non-crystalline cellulose, around 24 and 4.5 ms, respectively, at a 45 kHz B1 field. From the model, crystalline and non-crystalline regions in lyocell are estimated to each be around 2.5 nm thickness for a material of 50% crystallinity, consistent with the 2–3 nm dimensions derived from C4 peak devonvolution

Controlled accessibility Lewis acid catalysed thermal reactions of regenerated cellulosic fibres

A combination of techniques have been used to characterise lyocell regenerated cellulose fibre subjected to low-moisture thermal-catalytic reactions with zinc chloride Lewis acid. Application from non-swelling ethanol reduces catalyst accessibility, but at high temperatures migration takes place through the internal fibre morphology. The extent of chain scission is reduced at lower temperatures, leading to a higher leveling-off degree of polymerisation (LODP). In contrast, application of zinc chloride from water results in a lower LODP, due to the more even distribution of catalyst. The weights of extractable polymer material increase according to two separate rate constants, following established semicrystalline models. A higher Arrhenius activation energy for chain scission is seen for zinc chloride application from ethanol, which may be due to the physical mobilisation of the cellulose polymer at high temperature, associated with a cellulose Tg. This may also aid recrystallisation. Cellulose dehydration endotherms and pyrolysis exotherms are shifted to lower temperature for application of zinc chloride from ethanol compared to water, which may be the result of a higher local concentration of catalyst and a faster reaction onset