Enhancing the detection sensitivity of a high-resolution ß - γ coincidence spectrometer.

A high-resolution ß - Î³ coincidence spectrometry system has been set-up and calibrated at the UK CTBT Radionuclide Laboratory (known as GBL15) at AWE. The system has been configured specifically to measure the signatures of radioxenon isotopes that can be indicative of a nuclear explosion. The high purity germanium (HPGe) and PIPSBox detectors have been placed in an ultra-low-background lead shield to reduce the background count-rate and new software allows the combination of signals from four detectors (two HPGe detectors and two silicon-based detectors) to cover a larger solid angle. Measurements of samples of radioxenon isotopes are used to realise an improved detection efficiency and background acquisitions have demonstrated the achievable detection limits to reach 1.3 mBq for 133Xe and ≤0.3 mBq for the metastable isomers 131mXe and 133mXe. Due to the improved energy resolution in both photon and electron detectors, the detection sensitivity remains high in the presence of interfering signals from other radioxenon isotopes, such as those that may be present due to the significant levels of atmospheric radioxenon in parts of the world. This paper summarises the detector setup, efficiency calibration measurements and determination of the limits of detection. This work demonstrates the benefits of high-resolution coincidence detector systems for re-measurement of samples from the CTBT International Monitoring System (IMS) - improved detectability of metastable isomers 131mXe and 133mXe in the presence of 133Xe, compared to the current laboratory system.

Hollow microneedle assisted intradermal delivery of hypericin lipid nanocapsules with light enabled photodynamic therapy against skin cancer.

Photodynamic therapy (PDT) to manage non-melanoma skin cancers has garnered great attention over the past few years. Hypericin (Hy) is a potent lipid-soluble photosensitiser with promising anticancer therapeutic activities. Nevertheless, its poor water-solubility, aggregation in biological systems and insufficient skin penetration restricted its effective exploitation. Herein, we report for the first-time encapsulation of Hy into lipid nanocapsules (Hy-LNCs), and then application of an AdminPen™ hollow microneedles (Ho-MNs) array and an in-house fabricated Ho-MN to enable efficient intradermal delivery. The physicochemical properties, photoactivity, ex vivo drug distribution and cellular uptake were evaluated. Results showed that Hy-LNCs were successfully formed with a particle size of 47.76 ± 0.49 nm, PDI of 0.12 ± 0.02, high encapsulation efficiency (99.67% ± 0.35), 396 fold higher photoactivity, 7 fold higher skin drug deposition, significantly greater cellular uptake and higher photocytotoxicity compared to free Hy. The therapeutic effect of Hy-LNCs was finally assessed in vivo using a nude mouse model with transplanted tumours. Interestingly, Hy-LNCs delivered by Ho-MN exhibited remarkable anti-tumour destruction (85.84%) after irradiation with 595 nm. This study showed that Ho-MNs-driven delivery of Hy-LNCs followed by irradiation could form a promising minimally invasive, effective and site-specific approach for managing non-melanoma skin cancers.

Production and measurement of fission product noble gases.

Gaseous fission products have been produced via thermal neutron irradiation of a highly-enriched uranium target and extracted using a custom gas processing system for measurement on a prototype, high-resolution ß - Î³ coincidence detection system. The gas was extracted and measured in two stages in order to measure the prompt and ß--delayed fission products. This paper presents an overview of the system used to produce gaseous fission products, and the results of the advanced coincidence spectrometry techniques used to identify and quantify decays from the radionuclides produced, including the noble gases 85Kr, 85mKr, 88Kr, 133Xe, 135Xe, 133mXe and 135mXe, as well as 133I and 88Rb. The measurements were validated by determination of the nuclear decay half-lives, specifically for the ground state decay of 135Xe, which was found to be 9.15(49) hours and consistent with the literature value. This work demonstrates the UK capability to produce gaseous radionuclides for quality assurance and calibration purposes in Radionuclide Laboratories supporting the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

HtrA, RseP, and Tsp proteins do not elicit a pathology-related serum IgG response during sexually transmitted infection with Chlamydia trachomatis.

Chlamydia trachomatis sexually transmitted infection can cause serious reproductive morbidities. This study determined the prevalence of a serum IgG response to C. trachomatis putative stress response proteins in women, to test for an association with genital tract pathology. There was no significant association of serum IgG reactive with C. trachomatis HtrA, Tsp, or RseP with infection or pathology. cHSP60 serum IgG prevalence was significantly associated with infection compared to IgG negative infertile controls, but not with upper genital tract pathology. Serum IgG(1-4) antibody subclasses reactive with these antigens was not significantly different between cohorts, although different responses to each antigen were detected.

Preliminary investigation of the application of Raman spectroscopy to the prediction of the sensory quality of beef silverside.

The potential of Raman spectroscopy for the determination of meat quality attributes has been investigated using data from a set of 52 cooked beef samples, which were rated by trained taste panels. The Raman spectra, shear force and cooking loss were measured and PLS used to correlate the attributes with the Raman data. Good correlations and standard errors of prediction were found when the Raman data were used to predict the panels' rating of acceptability of texture (R(2)=0.71, Residual Mean Standard Error of Prediction (RMSEP)% of the mean (µ)=15%), degree of tenderness (R(2)=0.65, RMSEP% of µ=18%), degree of juiciness (R(2)=0.62, RMSEP% of µ=16%), and overall acceptability (R(2)=0.67, RMSEP% of µ=11%). In contrast, the mechanically determined shear force was poorly correlated with tenderness (R(2)=0.15). Tentative interpretation of the plots of the regression coefficients suggests that the α-helix to ß-sheet ratio of the proteins and the hydrophobicity of the myofibrillar environment are important factors contributing to the shear force, tenderness, texture and overall acceptability of the beef. In summary, this work demonstrates that Raman spectroscopy can be used to predict consumer-perceived beef quality. In part, this overall success is due to the fact that the Raman method predicts texture and tenderness, which are the predominant factors in determining overall acceptability in the Western world. Nonetheless, it is clear that Raman spectroscopy has considerable potential as a method for non-destructive and rapid determination of beef quality parameters.