Hydrogen isotopic analysis of nuclear reactor materials using ultrafast laser-induced breakdown spectroscopy.

Laser-induced breakdown spectroscopy is a promising method for rapidly measuring hydrogen and its isotopes, critical to a wide range of disciplines (e.g. nuclear energy, hydrogen storage). However, line broadening can hinder the ability to detect finely spaced isotopic shifts. Here, the effects of varying plasma generation conditions (nanosecond versus femtosecond laser ablation) and ambient environments (argon versus helium gas) on spectral features generated from Zircaloy-4 targets with varying hydrogen isotopic compositions were studied. Time-resolved 2D spectral imaging was employed to detail the spatial distribution of species throughout plasma evolution. Results highlight that hydrogen and deuterium isotopic shifts can be measured with minimal spectral broadening in a ∼ 10 Torr helium gas environment using ultrafast laser-produced plasmas.

Radiological-pathological correlation of negative CT biopsy results enables high negative predictive value for thoracic malignancy.

AIM: To evaluate multidisciplinary team (MDT) practice of radiological-pathological correlation of non-malignant biopsy results to examine the additive effect on the predictive values of computed tomography (CT) biopsy for malignancy and their subsequent management and outcomes. MATERIALS AND METHODS: A service evaluation of the MDT management of non-malignant lung biopsy results (May 2014- May 2017) was undertaken. RESULTS: Sixty patients had a non-malignant diagnosis on initial CT biopsy. Five patients were lost to follow-up leaving 55 in the final cohort. Forty-eight of the 55 patients had biopsy results classified as potentially non-specific, of which 26 were classified as concordant with radiology (e.g., organising pneumonia with compatible CT features), and 22 were classified as discordant (e.g., non-specific inflammation and yet sufficiently suspicious CT features). Patients with concordant negative pathology showed resolution (n=19) or stability (n=6) on imaging follow-up. One lesion demonstrated growth and was proven malignant on surgical resection. Discordant lesions were managed with repeat biopsy (n=8) or surgical resection (n=13), with 12 final benign diagnoses and nine malignancies. The negative predictive value of CT biopsy alone was 44/55 (80%), following repeat biopsy was 44/50 (88%), and following radiological-pathological assessment was 32/33 (97%). No patients underwent a shift in stage from time of biopsy to resection. CONCLUSION: Combining radiological-pathological interpretation of negative biopsy results offers superior negative predictive value for lung malignancy without delayed diagnosis of lung cancer.

A survey of UK percutaneous lung biopsy practice: current practices in the era of early detection, oncogenetic profiling, and targeted treatments.

AIM: To ascertain current percutaneous lung biopsy practices around the UK. MATERIALS AND METHODS: A web-based survey was sent to all British Society of Thoracic Imaging (BSTI) and British Society of Interventional Radiology (BSIR) members (May 2017) assessing all aspects of lung biopsy practice. Responses were collected anonymously. RESULTS: Two hundred and thirty-nine completed responses were received (28.8% response rate). Of the respondents, 48.5% worked in a teaching hospital and 51.5% in a district general hospital, while 32.6% (78/239) were specialist thoracic radiologists, 29.2% (70/239) "general" radiologists with a thoracic subspecialty interest, and 28% (67/239) interventional radiologists. Of the respondents, 30.1% (72/239) did not require pre-biopsy lung function tests (PFTs); 45.6% (108/237) stopped aspirin before the procedure; 97.5% primarily use computed tomography (CT) guidance for biopsy and 88.7% (212/239) perform core needle biopsy (CNB); and 86.6% of radiologists use a co-axial technique. There was wide variation in the number of samples routinely taken with most radiologists performing 1-2 passes (55.9%) or 3-4 passes (40.8%). Sixty-four percent reported using chest drain prevention techniques to minimise the impact of iatrogenic pneumothorax, with needle aspiration most frequent (43.9%). Timing of post-biopsy chest radiography (CXR), performed by 95.8% (228/239), also varied greatly: most commonly at either 1 hour (23%), 2 hours (24.7%), or 4 hours (22.6%). Moreover, the time of patient discharge after uncomplicated biopsy was variable, although the majority (66.1%) discharge patients after ≥4 hours. CONCLUSION: There are striking variations among surveyed UK radiologists performing lung biopsy in decision-making, pre-biopsy work-up, post-biopsy monitoring, management of pneumothorax, and discharge. The results suggest a need for new updated national percutaneous lung biopsy guidelines.

Mitochondrial DNA content of peripheral blood mononuclear cells in ART untreated & stavudine/zidovudine treated HIV-1-infected patients.

BACKGROUND & OBJECTIVES: Nucleoside reverse transcriptase inhibitors (NRTIs) are known to cause mitochondrial toxicity. This study was done to estimate mitochondrial DNA (mtDNA) content of peripheral blood mononuclear cells (PBMCs) among human immunodeficiency virus (HIV) infected, NRTI treated and antiretroviral therapy (ART)-naïve patients and evaluate the utility of mtDNA content as a biomarker of mitochondrial toxicity. METHODS: mtDNA content in PBMCs of 57 HIV-infected ART untreated and 30 ART treated with stavudine (d4T) or zidovudine (AZT) containing regimen were compared against 24 low-risk healthy controls (LoRHC). RESULTS: There was a significant (P=0.01) reduction in mtDNA content among HIV-infected (104; 80-135) compared to LoRHC (127; 110-167), and it was the same in both the treated (104.8; 88-130) and untreated patients (104.7; 78-142). mtDNA significantly (P=0.014) declined in ART treated patients symptomatic for toxicity (97; 74-111) than the asymptomatic patients (128; 103- 153). INTERPRETATION & CONCLUSIONS: mtDNA depletion in PBMCs was evident among HIV-infected individuals on ART. Moreover, as mtDNA content was reduced among the patients symptomatic for toxicity than the asymptomatic in both the HIV-infected groups, the current study supports mtDNA content of PBMCs to serve as a biomarker of mitochondrial dysfunction induced by NRTI and HIV. Longitudinal studies with a large sample need to be done to confirm these findings.

The influence of inspiratory effort and emphysema on pulmonary nodule volumetry reproducibility.

AIM: To evaluate the impact of inspiratory effort and emphysema on reproducibility of pulmonary nodule volumetry. MATERIALS AND METHODS: Eighty-eight nodules in 24 patients with emphysema were studied retrospectively. All patients had undergone volumetric inspiratory and end-expiratory thoracic computed tomography (CT) for consideration of bronchoscopic lung volume reduction. Inspiratory and expiratory nodule volumes were measured using commercially available software. Local emphysema extent was established by analysing a segmentation area extended circumferentially around each nodule (quantified as percent of lung with density of -950 HU or less). Lung volumes were established using the same software. Differences in inspiratory and expiratory nodule volumes were illustrated using the Bland-Altman test. The influences of percentage reduction in lung volume at expiration, local emphysema extent, and nodule size on nodule volume variability were tested with multiple linear regression. RESULTS: The majority of nodules (59/88 [67%]) showed an increased volume at expiration. Mean difference in nodule volume between expiration and inspiration was +7.5% (95% confidence interval: -24.1, 39.1%). No relationships were demonstrated between nodule volume variability and emphysema extent, degree of expiration, or nodule size. CONCLUSION: Expiration causes a modest increase in volumetry-derived nodule volumes; however, the effect is unpredictable. Local emphysema extent had no significant effect on volume variability in the present cohort.

UK Lung Cancer RCT Pilot Screening Trial: baseline findings from the screening arm provide evidence for the potential implementation of lung cancer screening.

BACKGROUND: Lung cancer screening using low-dose CT (LDCT) was shown to reduce lung cancer mortality by 20% in the National Lung Screening Trial. METHODS: The pilot UK Lung Cancer Screening (UKLS) is a randomised controlled trial of LDCT screening for lung cancer versus usual care. A population-based questionnaire was used to identify high-risk individuals. CT screen-detected nodules were managed by a pre-specified protocol. Cost effectiveness was modelled with reference to the National Lung Cancer Screening Trial mortality reduction. RESULTS: 247 354 individuals aged 50-75 years were approached; 30.7% expressed an interest, 8729 (11.5%) were eligible and 4055 were randomised, 2028 into the CT arm (1994 underwent a CT). Forty-two participants (2.1%) had confirmed lung cancer, 34 (1.7%) at baseline and 8 (0.4%) at the 12-month scan. 28/42 (66.7%) had stage I disease, 36/42 (85.7%) had stage I or II disease. 35/42 (83.3%) had surgical resection. 536 subjects had nodules greater than 50 mm(3) or 5 mm diameter and 41/536 were found to have lung cancer. One further cancer was detected by follow-up of nodules between 15 and 50 mm(3) at 12 months. The baseline estimate for the incremental cost-effectiveness ratio of once-only CT screening, under the UKLS protocol, was £8466 per quality adjusted life year gained (CI £5542 to £12 569). CONCLUSIONS: The UKLS pilot trial demonstrated that it is possible to detect lung cancer at an early stage and deliver potentially curative treatment in over 80% of cases. Health economic analysis suggests that the intervention would be cost effective-this needs to be confirmed using data on observed lung cancer mortality reduction. TRIAL REGISTRATION: ISRCTN 78513845.

Missed cancers in lung cancer screening--more than meets the eye.

In lung cancer, early detection and diagnosis is of paramount importance. In 2011 the National Lung Screening Trial (NLST) demonstrated the effectiveness of computed tomography (CT) screening for lung cancer in reducing mortality, and results from other ongoing trials are expected to be published in the near future. A topic that has not been widely researched to date, however, is the cause for screening failure and missed lung cancers. In this issue of European Radiology, Scholten et al. describe a number of causes for false-negative screens. Some of the implications for CT screening and nodule management raised by this report are discussed. Key Points • Many causes exist for missed lung cancers in CT screening trials • Endobronchial structures, the hila and mediastinum are blind spots on screening CTs • The management of atypical nodular opacities on thoracic CT may be challenging.

Subsurface synthesis and characterization of Ag nanoparticles embedded in MgO.

Metal nanoparticles exhibit a localized surface plasmon resonance (LSPR) which is very sensitive to the size and shape of the nanoparticle and the surrounding dielectric medium. The coupling between the electromagnetic radiation and the localized surface plasmon in metallic nanoparticles results in a sizable enhancement of the incident fields, making them possible candidates for plasmonic applications. In particular, partially exposed metallic nanoparticles distributed in a dielectric matrix can provide prime locations for LSPR spectroscopy and sensing. We report the synthesis and characterization of a plasmonic substrate consisting of Ag nanoparticles partially buried in MgO. Ag nanoparticles of different shapes and size distributions were synthesized below the surface of MgO by implanting 200 keV Ag(+) ions followed by annealing at 1000 °C for 10 and 30 h. A detailed optical and structural characterization was carried out to understand the evolution of the Ag nanoparticle and size distribution inside the MgO matrix. Micro x-ray diffraction (Micro-XRD) was employed to investigate the structural properties and estimate the crystallite size. The nanoparticles evolved from a spherical to a faceted morphology with annealing time, assuming an octahedral shape truncated at the (001) planes, as visualized from aberration-corrected transmission electron microscopy (TEM) images. The nanoparticles embedded in MgO were shown to be pure metallic Ag using atom probe tomography (APT). The nanoparticles were partially exposed to the surface by employing plasma etch techniques to remove the overlaying MgO. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the surface morphology and obtain a height distribution for the partially exposed nanoparticles.

Methyl 3'-benzyl-4'-(2-chloro-phen-yl)-1'-methyl-2-oxo-spiro-[indoline-3,2'-pyrrolidine]-3'-carboxyl-ate.

In the title compound, C27H25ClN2O3, the methyl-pyrrolidine ring adopts an envelope conformation with the N atom at the flap. The mean plane of the pyrrolidine ring makes dihedral angles of 82.1 (1), 84.4 (1) and 79.8 (1)°, respectively, with the adjacent benzene ring, the mean plane of the indoline ring system and the phenyl ring. The mol-ecular structure is stabilized by intra-molecular C-H⋯O hydrogen bonds. In the crystal, mol-ecules are linked into chains along [101] by N-H⋯O hydrogen bonds. C-H⋯π inter-actions are observed between the chains.

(E)-3-(1,3-Benzodioxol-5-yl)-2-{[N-(2-formylphenyl)-4-methylbenzenesulfon-amido]methyl}prop-2-enenitrile.

In the title compound, C(25)H(20)N(2)O(5)S, the benzodioxole ring system is essentially planar [maximum deviation = 0.021 (2) Å] and forms dihedral angles of 85.2 (1) and 74.2 (1)°, respectively, with the formyl benzene and sulfonyl-bound benzene rings. In the crystal, C-H⋯O hydrogen bonds generate C(8) chains along [100] and R(3) (3)(19) ring motifs. In addition, a weak π-π inter-action [centroid-centroid distance = 3.937 (3) Å] is also observed.

Methyl (E)-2-cyano-3-(6-nitro-1,3-benzodioxol-5-yl)acrylate.

In the title compound, C(12)H(8)N(2)O(6), the 1,3-benzodioxole ring system is essentially planar [maximum deviation = 0.036 (2) Å] and the nitro group is oriented at a dihedral angle of 15.4 (1)° with respect to its mean plane. In the crystal, moleucles are linked into C(8) [101] chains by C-H⋯O hydrogen bonds, and weak aromatic π-π stacking [centroid-centroid distance = 3.887 (1) Å] also occurs.

Methyl (E)-2-[(2-nitro-phen-oxy)meth-yl]-3-phenyl-acrylate.

The title compound, C(17)H(15)NO(5), adopts an E conformation with respect to the C=C double bond of the phenyl-acrylate unit. The phenyl ring and methyl acrylate group of the phenyl-acrylate unit are disordered over two sets of sites with site-occupancy ratios of 0.705 (5):0.295 (5) and 0.683 (3):0.317 (3), respectively. The mean plane through the benzene ring of the phenyl acrylate makes dihedral angles of 88.4 (8) (major component) and 86.7 (8)° (minor component) with the nitro-phen-oxy ring; the dihedral angle between the two components is 3.64 (6)°. Intra-molecular C-H⋯O interactions stabilise the molecular structure. In the crystal, C-H⋯O inter-actions result in a chain of mol-ecules running along the b axis.

2,2'-Diisopropoxy-5,5'-methyl-enedi-benz-alde-hyde.

Mol-ecules of the title compound, C(21)H(24)O(4), are located on a twofold rotation axis running through the central methyl-ene C atom. The aldehyde group is coplanar with the benzene ring [C-C-C-O = 175.7 (4) °].

Novel mixed-mode phase transition involving a composition-dependent displacive component.

Solid-solid displacive, structural phase transformations typically undergo a discrete structural change from a parent to a product phase. Coupling electron microscopy, three-dimensional atom probe, and first-principles computations, we present the first direct evidence of a novel mechanism for a coupled diffusional-displacive transformation in titanium-molybdenum alloys wherein the displacive component in the product phase changes continuously with changing composition. These results have implications for other transformations and cannot be explained by conventional theories.