Visualisation of J-type counter-current chromatography: A route to understand hydrodynamic phase distribution and retention

This article can be accessed from the link below - Copyright @ 2012 Elsevier. The article was made available through open access by the Brunel Open Access Publishing Fund.This paper has addressed decade sought-after questions on phase bilateral distribution and stationary phase retention in any J-type high-speed counter-current chromatographic (CCC) centrifuge. Using a 2-D spiral column operated on such a CCC device and an aqueous two-phase system, this work systematically observed the phase interaction during transitional period and at dynamic equilibration under stroboscopic illumination. The experimental results thus obtained were used to examine the effects of the liquid–solid friction force, tangential centrifugal force, and physical properties of the two-phase system on hydrodynamic phase behaviour. We identified that (a) density difference between lower and upper phases is the critical factor to cause unusual phase bilateral distribution in the 2-D spiral column and (b) interfacial tension (manifested primarily as phase settling time) of any two-phase system is the critical factor in explaining inability to retain stationary phase in 3-D helical column and, for certain flow modes, in the 2-D spiral column. This work thus has extended or modified the well-established rule-of-thumb for operating J-type CCC devices and our conclusions can accommodate virtually all the anomalies concerning both hydrophobic and hydrophilic phase systems. To this end, this work has not only documented valuable experimental evidences for directly observing phase behaviour in a CCC column, but also finally resolved fundamentally vital issues on bilateral phase distribution orientation and stationary phase retention in 2-D spiral and 3-D helical CCC columns. Revised recommendations to end users of this technology could thus be derived out of the essence of the present work presumably following further experimental validation and a consensus in the CCC R&D and manufacturing circle.This work is funded by the BBSRC (UK) grant BB/C5063341/1, by MoST (China) as a Major State Basic Research Development Programme grant 2007CB714303 (973 Programme), by M & G Trading, and by Shanghai Science and Technology Board grant 11DZ2292700

The programmable processor

[EN] Reconfigurable optical chips made from 2D meshes of connected waveguides could pave the way for programmable, general purpose microwave photonics processors.Capmany Francoy, J.; Gasulla Mestre, I.; Pérez-López, D. (2016). The programmable processor. Nature Photonics. 10:6-8. doi:10.1038/nphoton.2015.254S6810Waterhouse, R. & Novak, D. IEEE Microwave Mag. 16, 84–92 (2015).Skubic, B., Bottari, G., Rostami, A., Cavaliere, F. & Ölen, P. IEEE J. Lightwave Technol. 33, 1084–1091 (2015).Nature Photonics Technology Focus http://www.nature.com/nphoton/journal/v5/n12/techfocus/index.html (2011).Marpaung, D. et al. Lasers Phot. Rev. 7, 506–538 (2013).Pérez, D., Gasulla, I. & Capmany, J. Opt. Express 23, 14640–14654 (2015).Zhuang, L. et al. Optica 2, 854–859 (2015).Smit, M. et al. Semicond. Sci. Technol. 28, 083001 (2014).Guan, B. B. et al. IEEE J. Sel. Top. Quantum Electron. 20, 359–368 (2014).Wang, J. et al. Nature Commun. 6, 5957 (2015).Miller, D. A. B. Optica 2, 747–750 (2015)

The living specimen : Guan Wei : a Chinese-Australian artist

This thesis focuses on the work and experience of Guan Wei. Guan Wei is a Chinese born artist now living and working in Australia. He is one of a number of mainland Chinese who came to live in Australia in the late 1989s and early 1990s. While there are certain commonalities between the experiences of these artists, I have concentrated on Guan Wei not merely as a case study for recent emigre Chinese artists in Australia, but because of his prominent place in Australian contemporary art

The structure of hot gas in Cepheus B

By observing radiation-affected gas in the Cepheus B molecular cloud we probe whether the sequential star formation in this source is triggered by the radiation from newly formed stars. We used the dual band receiver GREAT onboard SOFIA to map [C II] and CO 13--12 and 11--10 in Cep B and compared the spatial distribution and the spectral profiles with complementary ground-based data of low-$J$ transitions of CO isotopes, atomic carbon, and the radio continuum. The interaction of the radiation from the neighboring OB association creates a large photon-dominated region (PDR) at the surface of the molecular cloud traced through the photoevaporation of C^+. Bright internal PDRs of hot gas are created around the embedded young stars, where we detect evidence of the compression of material and local velocity changes; however, on the global scale we find no indications that the dense molecular material is dynamically affected.Comment: Accepted for publication in A&A (SOFIA/GREAT special issue

Some Predictions of Diquark Model for Hidden Charm Pentaquark Discovered at the LHCb

The LHCb has discovered two new states with preferred $J^P$ quantum numbers $3/2^-$ and $5/2^+$ from $\Lambda_b$ decays. These new states can be interpreted as hidden charm pentaquarks. It has been argued that the main features of these pentaquarks can be described by diquark model. The diquark model predicts that the $3/2^-$ and $5/2^+$ are in two separate octet multiplets of flavor $SU(3)$ and there is also an additional decuplet pentaquark multiplet. Finding the states in these multiplets can provide crucial evidence for this model. The weak decays of b-baryon to a light meson and a pentaquark can have Cabibbo allowed and suppressed decay channels. We find that in the $SU(3)$ limit, for $U$-spin related decay modes the ratio of the decay rates of Cabibbo suppressed to Cabibbo allowed decay channels is given by $|V_{cd}|^2/|V_{cs}|^2$. There are also other testable relations for b-baryon weak decays into a pentaquark and a light pseudoscalar. These relations can be used as tests for the diquark model for pentaquark.Comment: revtex, 19 pages, 3 figures. one reference added and some typos correcte