Shape evolution in the rapidly rotating 140^{140}Gd nucleus

Ground state band of $^{140}$Gd has been investigated following their population in the $^{112}$Sn($^{35}$Cl,~$\alpha$p2n)$^{140}$Gd reaction at 195 MeV of beam energy using a large array of Compton suppressed HPGe clovers as the detection setup. Apart from other spectroscopic measurements, level lifetimes of the states have been extracted using the Doppler Shift Attenuation Method. Extracted quadrupole moment along with the pairing independent cranked Nilsson-Strutinsky model calculations for the quadrupole band reveal that the nucleus preferably attains triaxiality with $\gamma$ = -30$^\circ$. The calculation though shows a slight possibility of rotation around the longest possible principal axis at high spin $\sim$ 30$\hbar$ which is beyond the scope of the present experiment

Sequence and comparative analysis of the genome of HSV-1 strain McKrae

Ocular infection by HSV-1 strain McKrae is neurovirulent in both mice and rabbits and causes fatal encephalitis in approximately 50% of animals. In addition, it spontaneously reactivates with high frequency relative to other HSV-1 strains in rabbits. We sequenced the McKrae strain genome and compared its coding protein sequences with those of six other HSV-1 strains. Most of the 74 predicted protein sequences are conserved; only eleven are less than 98% conserved. Eight proteins were identified to be unique for McKrae based on sequence homology bit score ratio (BSR). These include five proteins showing significant variations (RL1, RS1, UL49A, US7, US11), two truncated proteins (UL36 and UL56) and one (US10) containing an extended open reading frame. The McKrae strain also has unique features in its ‘a’ sequence and non-coding sequences, such as LAT and miRNA. These data are indicative of strain variation but need further work to connect observed differences with phenotype effects.Keywords: DNA sequence comparison, High throughput DNA sequencing, Herpes viru

Applications of supramolecular polymer networks

This perspectives article reviews selected key examples from the field of supramolecular polymer chemistry with the specific focus on the use of the dynamic properties that these materials possess in real-world applications. The scope of application for these fascinating materials, typically networks held in place by numerous weak, non-covalent bonds, has proven to be extremely diverse – significant effort in the past twenty years has enabled supramolecular polymers to now be found in developmental adhesives, batteries, anti-fouling coatings, healable barriers and regenerative medicines. Indeed, in recognition of the potential of these polymer chemistries, spin-out companies have been formed to exploit the commercial space that exists for materials with dynamic and reversible characteristics. The latter attribute is desirable in manufacturing materials and devices that can be recycled and reused

Fluoride-responsive debond on demand adhesives: manipulating polymer crystallinity and hydrogen bonding to optimise adhesion strength at low bonding temperatures

This paper reports the solvent-free synthesis of a series of six fluoride responsive debond-on-demand polyurethane (PU) adhesives that contain a silyl functionalised degradable unit (DU). To optimise the adhesion strength and debonding nature of the adhesives, the chemical composition of the PUs was varied according to the structure of the polyol or the diisocyanate component in the polymer mainchain. 1H NMR spectroscopy was used to study the depolymerisation behaviour in solution state. It showed that tetra-butylammonium fluoride (TBAF) triggered the breakdown of the DU unit without fragmenting the polyol mainchain indiscriminately. On exposure to fluoride ions, the PUs underwent depolymerisation with reductions in Mn ranging from 64 to 90% as measured by GPC analysis. The morphology and thermal properties of the PUs were characterised by differential scanning calorimetry (DSC), rheology and variable temperature (VT) SAXS/WAXS analysis. Each technique demonstrated the reversibility of the supramolecular polymer network under thermal stimuli. PUs containing poly(butadiene) soft segments were amorphous with glass transition and viscoelastic transition temperatures dependent on the nature of the soft segment and diisocyanate starting materials. The PU containing a polyester soft segment exhibited a defined melting point at 49 °C. Mechanical stress-strain analysis of the series of PUs showed each exhibited greater than 70% reduction in toughness after treatment with TBAF for 30 min as a consequence of the chemo-responsive degradation of the polymer mainchain. The material featuring an ester-based polyol demonstrated excellent adhesion at bonding temperatures as low as 60 °C. Moreover, this material could be thermally rebonded if broken by force without loss in adhesion strength over three debond-rebond cycles. Lap shear adhesion tests showed a reduction in adhesive strength of approximately 40% (from 11.4 MPa to 7.3 MPa) on exposure to fluoride ions

Development of a position-sensitive fast scintillator (LaBr

We have characterized a Cerium doped Lanthanum Bromide (LaBr3(Ce) ) crystal coupled with the position-sensitive photo-multiplier system for the gamma-ray imaging application. One can use this detector set-up for the scanning of high purity germanium detectors for pulse shape analysis in gamma-ray spectroscopy experiments and the image formation of an object by Compton back-scattering . The sensor has been tested for energy, timing and position information of the gamma-rays interacting within the detector crystal. The GEANT4 simulation results are consistent with the experimental results. We have reconstructed the image of irradiation spots in different positions throughout the detector crystal. Position resolution is found to be around 3.5 mm with the 2 mm collimated gamma-rays. The 2-d image of hexagonal Bismuth Germanate (BGO) crystal and a cylindrical LaBr3(Ce) crystal have been reconstructed in coincidence technique. The performance of the detector for imaging application has been investigated by coincidence technique in GEANT4 simulation and compared with the experimental data. We have reconstructed the 2-d images of objects with various geometrical shapes by Compton back-scattered events of the gamma-rays. This position-sensitive detector can be used as an absorber of a Compton camera for the image reconstruction of an extended radioactive source. One can also use this kind of set-up as in radiation imaging and many other applications where the energy and source position of the gamma-ray is the main interest