Kinetics of semicarbazide and nitrofurazone in chicken eggs and egg powders

The accumulation, depletion and partitioning of semicarbazide (SEM) and its parent compound nitrofurazone (NFZ) in eggs were studied using hens fed NFZ at therapeutic and sub-therapeutic levels. Dietary NFZ correlated strongly with NFZ and total SEM in eggs, while 28% of observed SEM was present in the form of parent NFZ. Depletion half-life in eggs was 2.4 days for SEM and 1.1 days for NFZ. NFZ accumulated preferentially in yolk (57-63%) as opposed to albumen, while 71-80% of SEM was found in yolk. In whole egg, 29% of SEM was present as tissue-bound residues compared with 80% in breast muscle. Whilst NFZ and SEM were partly degraded by pasteurization and spray drying, sufficient NFZ remained to suggest it might be detectable in egg powders when SEM is observed at low µg kg -1 concentrations. NFZ was detectable in whole eggs during ingestion of only 0.1% of the therapeutic NFZ dose, making detection of intact NFZ in eggs a feasible means to prove conclusively the administration of this banned compound.

Magnetic properties of copper hexadecaphthalocyanine (F16CuPc) thin films and powders

The structural and magnetic properties of F16CuPc thin films and powder, including x-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometry, and theoretical modelling of exchange interactions are reported. Analysis of XRD from films, with thickness ranging between 100 and 160 nm, deposited onto Kapton and a perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) interlayer shows that the stacking angle (defined in the text) of the film is independent of the thickness, but that the texture is modified by both film thickness and substrate chemistry. The SQUID measurements suggest that all samples are paramagnetic, a result that is confirmed by our theoretical modelling including density functional theory calculations of one-dimensional molecular chains and Green's function perturbation theory calculations for a molecular dimer. By investigating theoretically a range of different geometries, we predict that the maximum possible exchange interaction between F16CuPc molecules is twice as large as that in unfluorinated copper-phthalocyanine (CuPc). This difference arises from the smaller intermolecular spacing in F16CuPc. Our density functional theory calculation for isolated F16CuPc molecule also shows that the energy levels of Kohn-Sham orbitals are rigidly shifted similar to 1 eV lower in F16CuPc compared to CuPc without a significant modification of the intramolecular spin physics, and that therefore the two molecules provide a suitable platform for independently varying magnetism and charge transport. 

Moisture and temperature dependence of the dielectric properties of pharmaceutical powders

The dielectric properties of pharmaceutical powder-(paracetamol, aspirin, lactose, maize starch, adipic acid) solvent (water) mixtures were measured at 2,450 MHz at a range of moisture contents (0-1.0 kg kg(-1), dry basis) and temperatures (20-70 A degrees C). The dielectric constant (epsilon'), loss factor (epsilon aEuro(3)) and penetration depth (d (p)) were found to be dependent on frequency, moisture content, temperature and powder type. For powder-water mixtures, a linear increase in the dielectric properties with moisture content was observed, whilst the temperature dependence was of quadratic form. The penetration depth was also significantly affected by temperature and moisture content. Although, epsilon aEuro(3) also increased with increasing temperature, variation with moisture content was temperature dependent. This information on dielectric properties is essential for mathematical description of the pharmaceutical product temperature history during microwave heating and for the design of microwave drying equipment.

LIQUID MARBLES GRANULATED USING SUPER-HYDROPHOBIC METAL POWDERS

Superhydrophobic (SH) particles based on a copper substrate were prepared by a silver deposition technique of different particle sizes from 10µm to 425µm. Such SH particles were found to be pH-responsive and liquid marbles formed using the SH copper substrate destabilised under certain pH conditions. The exposure to high concentrations of acidic or basic gases caused immediate collapse of the liquid marble. However, low concentrations of acidic and basic gases could diffuse across the shell of liquid marbles without adversely affecting the structure. Liquid marbles formed with large SH particles (425
µm) did not fully form a mono-layer around the liquid droplet. This phenomenon, whereby SH particles slide down the surface of the water droplet until an equilibrium position is reached, was studied using a mathematical approach, which related the angle to the vertical axis of the SH particles at t
he equilibrium F, to the shape of liquid marble and the contact angle, ?.

Nile blue-based nano-sized pH sensors for simultaneous far-red and near-infrared live bioimaging

Diblock copolymer vesicles are tagged with pH-responsive Nile Blue-based labels and used as a new type of pH-responsive colorimetric/fluorescent biosensor for far-red and near-infrared imaging of live cells. The diblock copolymer vesicles described herein are based on poly(2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(diisopropylamino)ethyl methacrylate) [PMPC-PDPA]: the biomimetic PMPC block is known to facilitate rapid cell uptake for a wide range of cell lines, while the PDPA block constitutes the pH-responsive component that enables facile vesicle self-assembly in aqueous solution. These biocompatible vesicles can be utilized to detect interstitial hypoxic/acidic regions in a tumor model via a pH-dependent colorimetric shift. In addition, they are also useful for selective intracellular staining of lysosomes and early endosomes via subtle changes in fluorescence emission. Such nanoparticles combine efficient cellular uptake with a pH-responsive Nile Blue dye label to produce a highly versatile dual capability probe. This is in marked contrast to small molecule dyes, which are usually poorly uptaken by cells, frequently exhibit cytotoxicity, and are characterized by intracellular distributions invariably dictated by their hydrophilic/hydrophobic balance.

Synthesis of Co3O4 nano-octahedra enclosed by {111} facets and their excellent lithium storage properties as anode material of lithium ion batteries

Abstract
Nano-sized(nO-Co3O4, 387nm)andmicron-sized(mO-Co3O4, 6.65 mm) Co3O4 octahedraenclosedby
{111}facetshavebeenbothsynthesizedthroughawetchemicalmethodfollowedbythermal
treatment,andservedasanodematerialoflithium ionbatteries(LIBs).Electrochemicalresults
demonstratethatthenO-Co3O4 showsexcellentlongcyclabilityandratecapability.ThenO-Co3O4
candeliverastablechargecapacityashighas955.5mAhg1 upto200cycleswithoutnoticeable
capacityfadingatacharge/dischargecurrentdensityof0.1Ag1 (ca. 0.11C).Theexcellent
electrochemicalperformanceisascribedtothenano-sizeandthe{111}facetsthatenclosethe
octahedra. WhilethemO-Co3O4 could onlymaintain288.5mAhg1 after 200cycles,illustratingvery
poorcyclingperformance,whichisascribedtothelargeparticlesizethatmaycausehugevolume
changeduringrepeatedcharging/discharging process.TheresultsrevealthattheCo3O4 nano-
octahedrawouldbeapromisinganodematerialforthenext-generationofLIBs.

Water-mediated electrochemical nano-writing on thin ceria films

Bias dependent mechanisms of irreversible cathodic and anodic processes on a pure CeO2 film are studied using modified atomic force microscopy (AFM). For a moderate positive bias applied to the AFM tip an irreversible electrochemical reduction reaction is found, associated with significant local volume expansion. By changing the experimental conditions we are able to deduce the possible role of water in this process. Simultaneous detection of tip height and current allows the onset of conductivity and the electrochemical charge transfer process to be separated, further elucidating the reaction mechanism. The standard anodic/cathodic behavior is recovered in the high bias regime, where a sizable transport current flows between the tip and the film. These studies give insight into the mechanisms of the tip-induced electrochemical reactions as mediated by electronic currents, and into the role of water in these processes, as well as providing a different approach for electrochemical nano-writing.

Can a carbon nano-coating resist metallic phase transformation in silicon substrate during nanoimpact?

Nanomechanical response of a silicon specimen coated with a sp3 crystalline carbon coating (1.8 nm thickness) was investigated using MD simulation. A sharp conical rigid tip was impacted at the speed of 50 m/sec up to a depth of ~80% of the coating thickness. Unlike pure silicon specimen, no metallic phase transformation was observed i.e. a thin coating was able to resist Si-I to Si-II metallic phase transformation signifying that the coating could alter the stress distribution and thereby the contact tribology of the substrate. The stress state of the system, radial distribution function and the load-displacement curve were all aligned with above observations

Investigation of Finish-cut of Microelectrodischarge Milling for Nano Surface Finish

In this article, the machining conditions to achieve nanometric surface roughness in finish cut microelectrodischarge milling were investigated. For a constant gap voltage, the effect of feed rate and capacitance was studied on average surface roughness (Ra) and maximum peak-to-valley roughness height (Ry). Statistical models were developed using a three-level, two-factor experimental design. The developed models minimized Ra and Ry by desirability function approach. Maximum desirability was found to be more than 98%. The minimum values of Ra and Ry were 23 and 173 nm, respectively, for 1.00 μm s-1 feed rate and 0.01 nF capacitance. Verification experiments were conducted to check the accuracy of the models, where the responses were found to be very close to the predicted values. Thus, the developed models can be used to generate nanometric level surface finish, which are useful for many applications in microelectromechanical systems.