Much of George Dracoulis’s research career was devoted to utilising gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in ...the area of nuclear forensics. Over the last several years, our research group has made use of both high- and low-resolution gamma-ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.
Fluorescent probes for monitoring mitochondrial membrane potential are frequently used for assessing mitochondrial function, particularly in the context of cell fate determination in biological and ...biomedical research. However, valid interpretation of results obtained with such probes requires careful consideration of numerous controls, as well as possible effects of non-protonic charges on dye behavior. In this context, we provide an overview of some of the important technical considerations, controls, and parallel complementary assays that can be employed to help ensure appropriate interpretation of results, thus providing a practical usage guide for monitoring mitochondrial membrane potentials with cationic probes. In total, this review will help illustrate both the strengths and potential pitfalls of common mitochondrial membrane potential dyes, and highlight best-usage approaches for their efficacious application in life sciences research.
A novel technique for β-delayed neutron spectroscopy has been demonstrated using trapped ions. The neutron-energy spectrum is reconstructed by measuring the time of flight of the nuclear recoil ...following neutron emission, thereby avoiding all the challenges associated with neutron detection, such as backgrounds from scattered neutrons and γ rays and complicated detector-response functions. (137)I(+) ions delivered from a (252)Cf source were confined in a linear Paul trap surrounded by radiation detectors, and the β-delayed neutron-energy spectrum and branching ratio were determined by detecting the β(-) and recoil ions in coincidence. Systematic effects were explored by determining the branching ratio three ways. Improvements to achieve higher detection efficiency, better energy resolution, and a lower neutron-energy threshold are proposed.
An active veto system consisting of plastic scintillation panels was installed outside the Pb shielding of a 115% n-type HPGe detector in an effort to reduce background continuum generated by cosmic ...ray muons on the surface. The Low Background Facility at the Lawrence Berkeley National Laboratory performs low level assay (generally of primordial U, Th, K) of candidate construction materials for experiments that require a high level of radiopurity. The counting is performed in two facilities: one local surface site and a remote underground site of approximately 600m.w.e. For the recently installed veto system at the surface location, the top scintillator panel has been in use for nearly 1year and the full 3π anticoincidence shield was commissioned into normal counting operations in January 2013. The integrated background from 20 to 3600keV is reduced overall by a factor of 8, where most of the energy spectrum above 100keV achieves an overall reduction that varies from 8 to 10. A dramatic improvement of peak-to-background across the entire continuum is observed, greatly enhancing low-level peaks that would otherwise be obscured.
IntroductionThe STOPPIT-2 study aims to determine the clinical utility of the Arabin cervical pessary in preventing preterm birth in women with a twin pregnancy and a short cervix, about which there ...is current uncertainty. STOPPIT-2 will resolve uncertainty around effectiveness for women with a twin pregnancy and a cervical length of 35 mm or less, define adverse effects, ascertain acceptability and estimate National Health Service costs and savings.MethodsSTOPPIT-2 is a pragmatic multicentre open-label randomised controlled trial. Consenting women with twin pregnancy will have an transvaginal ultrasound scan of their cervical length performed between 18+0 and 20+6 weeks’ gestation by an accredited practitioner: women with a cervical length of ≤35 mm will be eligible for inclusion in the treatment phase of the study. The intervention by the insertion of the Arabin cervical pessary will be compared with standard treatment (no pessary).The primary outcomes are (obstetric) spontaneous onset of labour for the mother leading to delivery before 34 weeks’ gestation and (neonatal) a composite of specific adverse outcomes or death occurring up to the end of the first 4 weeks after the estimated date of delivery to either or both babies.We plan to recruit 500 women in the treatment phase of the study. Assuming a treatment effect of 0.6, and background rates of 35% and 18%, respectively, for each of the primary outcomes, our study has 85% power to detect a difference between the intervention and the control groups.AnalysisData will be analysed on the intention-to-treat principle.EthicsSTOPPIT-2 was approved by the South East Scotland Ethics Committee 02 on 29 August 2014, reference number 14/SS/1031 IRAS ID 159610.DisseminationPeer reviewed journals, presentations at national and international scientific meetings.Trial registration number ISRCTN98835694 and NCT02235181.
Background: Optical coherence tomography is a new, high spatial–resolution, cross-sectional imaging technique. We investigated the ability of optical coherence tomography to provide detailed images ...of subsurface structures in the upper gastrointestinal (GI) tract.
Methods: Optical coherence tomography was performed during routine upper GI endoscopy on 32 patients including 20 patients with Barrett's esophagus. An endoscopic mucosal biopsy was obtained immediately after imaging and was used for histopathologic correlation.
Results: Optical coherence tomography provided clear delineation of layers of the normal human esophagus extending from the epithelium to the longitudinal muscularis propria. Gastric mucosa was differentiated from esophageal mucosa, Barrett's esophagus was differentiated from normal esophageal mucosa, and esophageal adenocarcinoma was distinguished from normal esophagus and Barrett's esophagus.
Conclusions: Optical coherence tomography allows visualization of the subsurface architectural morphology of the upper GI tract. The diagnostic information provided by this new imaging modality suggests that it may be a useful adjunct to endoscopy.
The venom of Antarctic octopus remains completely unstudied. Here, a preliminary investigation was conducted into the properties of posterior salivary gland (PSG) extracts from four Antarctica ...eledonine (Incirrata; Octopodidae) species (
Adelieledone polymorpha, Megaleledone setebos,
Pareledone aequipapillae, and
Pareledone turqueti) collected from the coast off George V’s Land, Antarctica. Specimens were assayed for alkaline phosphatase (ALP), acetylcholinesterase (AChE), proteolytic, phospholipase A
2 (PLA
2), and haemolytic activities. For comparison, stomach tissue from
Cirroctopus sp. (Cirrata; Cirroctopodidae) was also assayed for ALP, AChE, proteolytic and haemolytic activities. Dietary and morphological data were collected from the literature to explore the ecological importance of venom, taking an adaptive evolutionary approach.
Of the incirrate species, three showed activities in all assays, while
P. turqueti did not exhibit any haemolytic activity. There was evidence for cold-adaptation of ALP in all incirrates, while proteolytic activity in all except
P. turqueti.
Cirroctopus sp. stomach tissue extract showed ALP, AChE and some proteolytic activity. It was concluded that the AChE activity seen in the PSG extracts was possibly due to a release of household proteins, and not one of the secreted salivary toxins. Although venom undoubtedly plays an important part in prey capture and processing by Antarctica eledonines, no obvious adaptations to differences in diet or morphology were apparent from the enzymatic and haemolytic assays. However, several morphological features including enlarged PSG, small buccal mass, and small beak suggest such adaptations are present. Future studies should be conducted on several levels: Venomic, providing more detailed information on the venom compositions as well as the venom components themselves; ecological, for example application of serological or genetic methods in identifying stomach contents; and behavioural, including observations on capture of different types of prey.
The CUPID-Mo experiment at the Laboratoire Souterrain de Modane (France) is a demonstrator for CUPID, the next-generation ton-scale bolometric 0νββ experiment. It consists of a 4.2 kg array of 20 ...enriched Li2 100MoO4 scintillating bolometers to search for the lepton-number-violating process of 0νββ decay in 100Mo. With more than one year of operation (100Mo exposure of 1.17 kg × yr for physics data), no event in the region of interest and, hence, no evidence for 0νββ is observed. We report a new limit on the half-life of 0νββ decay in 100Mo of T1/2 > 1.5 × 1024 yr at 90% C.I. The limit corresponds to an effective Majorana neutrino mass ⟨m β β⟩ < (0.31 –0.54 ) eV, dependent on the nuclear matrix element in the light Majorana neutrino exchange interpretation.
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