Genetic, genomic and physiological state studies on single-needle bio-electrosprayed human cells

Bio-electrospraying, a non-contact jet-based direct cell engineering approach, was recently pioneered and demonstrated for handling a wide range of primary living cells. In those studies, post-treated cells were biologically assessed in comparison to several controls by way of flow cytometry. Although flow cytometry accurately assesses those viable populations of cells, subtle effects at a sub-cellular level could have been missed. Therefore, in the present study we demonstrate metaphase chromosome breakage studies carried out on single-needle bio-electrosprayed human T-lymphocytes, which are compared with several controls. The results indicate that post-treated T-lymphocytes do not demonstrate any increase in chromosome damage in comparison to control cells. These studies further validate bio-electrospraying as a technique with potential for clinical utility.     

关于Hirota-Satsuma系统初值问题的局部和整体适定性

本文利用ＫＤＶ方程所对应的线性方程解所具有的光滑效应及压缩映像原理,得到了Ｈｉｒｏｔａ－Ｓａｔｓｕｍａ系统初值问题的局部和整体适定性结果．     

Overlapping B3Π0u ← X1Σ g/+ and 1Π1u ← X1Σ g/+ non-radiative characteristic of Br2 vapour in the wavelength region 505–541 nm

The vibronic vapour phase photoacoustic spectrum of Br₂ in the wavelength region 505–541 nm (19796–18480 cm⁻¹) has been recorded using microphone as well as pump-probe method. Discrete vibronic bands superimposed on a monotonically increasing continuum background towards the dissociation limit results from the overlapping B ³Π _0u ^/+ ← X ¹Σ _g ^/+ and ¹Π_1u ← X ¹Σ _g ^/+ electronic transitions. Vibronic bands originating from υ″=0 have been used to estimate the relative rate of non-radiative relaxation as a function of the excited state B ³Π_0u vibrational quantum number υ′. A comparison with the optical absorption spectroscopy of Br₂ leads to the identification of three broad spectral regions between 505 and 541 nm (19796 and 18480 cm⁻¹) on the basis of different non-radiative relaxation processes.     

Coaxial electrohydrodynamic direct writing of nano-suspensions

Two monodisperse nano-suspensions, which contain 20-nm and 120-nm silica particles (30 wt.%), were electrohydrodynamically jetted simultaneously in coaxial needles. Irrespective of which suspension was in the inner or outer needle, the cone-jet mode was obtained and the droplets resulting from jet break-up were used to direct write ∼80 μm lines. Turbulent flow in the cones ensured that the suspensions were subjected to intense mixing and therefore the microstructure contains a random mixture of the two types of nanoparticles of unchanged morphology.     

Steroidal and triterpenoidal saponins from the fruits of Diploclisia glaucescens

Chemical investigation of methanol extract of the fruits of Diploclisia glaucescens furnished 3-O-beta-D-glucopyranosyl-20-hydroxyecdysone, 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]serjanic acid 28-O-beta-D-glucopyranosyl ester and 3-O-[beta-xylopyranosyl(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]serjanic acid 28-O-beta-D-glucopyranosyl ester. The latter saponin was found to be a new natural product while the other two are reported for the first time from the family Menispermaceae.     

Stable electric-field driven cone-jetting of concentrated biosuspensions

Electrospraying, or electrohydrodynamic jetting, is one of several jet-based technologies being explored to process living biological organisms. One of the key advantages of electrospraying is its ability to deposit advanced materials with high resolution that cannot be obtained with other competing technologies, such as ink-jet printing. However, to generate a controlled droplet size distribution in the micrometre range necessary for precision drop and placement of materials requires jetting in stable cone-jet mode. In this paper, we describe the experimental set-up and conditions by which electrospray jetting in stable cone-jet is achieved and use this methodology to process a highly concentrated biological suspension having 10(7) cells ml(-1), the highest cellular loading processed to this day by a jetting approach in this jet based category. The areas of study to which this technology may be applied span the physical and the life sciences.     

Nematicidal activity of some Sri Lankan plants

Nineteen solvent extracts from seven Sri Lankan plants were examined for nematicidal activity against the root knot nematode Meloidogyne incognita. Extracts of Allophyhu cobbe, Lepisanthes tetraphylla (Sapindaceae), Sarcococca zeylanica (Buxaceae) and Hedyotis lawsoniae (Rubiaceae) have shown significant nematicidal activity.