Probing the interaction between solid benzene and water using vacuum ultraviolet and infrared spectroscopy

We present results of a combined vacuum ultravioloet (VUV) and infrared (IR) photoabsorption study of amorphous benzene:water mixtures and layers to investigate the benzene-water interaction in the solid phase. UV spectra of 1:1, 1:10 and 1:100 benzene:water mixtures at 24 K reveal a concentration dependent shift in the energies of the 1B2u, 1B1u and 1E1u electronic states of benzene. All the electronic bands blueshift from pure amorphous benzene towards gas phase energies with increasing water concentration. IR results reveal a strong dOH-π benzene-water interaction via the dangling OH stretch of water with the delocalised π system of the benzene molecule. Although this interaction influences the electronic states of benzene with the benzenewater interaction causing a redshift in the electronic states from that of the free benzene molecule, the benzene-benzene interaction has a more significant effect on the electronic states of benzene. VUV spectra of benzene and water layers show evidence of non-wetting between benzene and water, characterised by Rayleigh scattering tails at wavelengths greater than 220 nm. Our results also show evidence of benzene-water interaction at the benzene-water interface affecting both the benzene and the water electronic states. Annealing the mixtures and layers of benzene and water show that benzene remains trapped within in/under water ice until water desorption near 160 K. These first systematic studies of binary amorphous mixtures in the VUV, supported with complementary IR studies, provide a deeper insight into the influence of intermolecular interactions on intramolecular electronic states with significant implications for our understanding of photochemical processes in more realistic astrochemical environments

Signatures of the non-Maxwellian κ\kappa-distributions in optically thin line spectra. II. Synthetic Fe XVII--XVIII X-ray coronal spectra and predictions for the Marshall Grazing-Incidence X-ray Spectrometer (MaGIXS)

We investigated the possibility of diagnosing the degree of departure from the Maxwellian distribution using the Fe XVII - Fe XVIII spectra originating in plasmas in collisional ionization equilibrium, such as in the cores of solar active regions or microflares. The original collision strengths for excitation are integrated over the non-Maxwellian electron $\kappa$-distributions characterized by a high-energy tail. Synthetic X-ray emission line spectra were calculated for a range of temperatures and $\kappa$. We focus on the 6-24 A spectral range to be observed by the upcoming Marshall Grazing-Incidence X-ray Spectrometer MaGIXS. We find that many line intensity ratios are sensitive to both $T$ and $\kappa$. Best diagnostic options are provided if a ratio involving both Fe XVII and Fe XVIII is combined with another ratio involving lines formed within a single ion. The sensitivity of such diagnostics to $\kappa$ is typically a few tens of per cent. Much larger sensitivity, of about a factor of two to three, can be obtained if the Fe XVIII 93.93 A line observed by SDO/AIA is used in conjuction with the X-ray lines. We conclude that the MaGIXS instrument is well-suited for detection of departures from the Maxwellian distribution, especially in active region cores.Comment: Astronomy & Astrophysics, accepte

Robotic Techniques in Thoracic Surgery

Background: Minimally invasive techniques for thoracic surgery are safe and result in fewer complications compared with traditional open surgery. There may be advantages in adopting robotic thoracic surgery compared to video-assisted thoracoscopic surgery (VATS). Despite the surge in robotic thoracic surgery in the UK, good quality evidence is needed to substantiate the associated high capital costs and service fees. Aims: To assess the impact of introducing a robotic thoracic surgery programme at Liverpool Heart and Chest Hospital (LHCH) and determine the clinical benefit and cost associated with robotic surgery for lung cancer resection; as well as mediastinal mass resection and lung volume reduction surgery (LVRS), compared to the more commonly used surgical approaches (open and VATS). This research reports on LHCH preparations for the COLT trial; a multicentre prospective cohort study comparing robotic, VATS and open techniques for lobectomy for early-stage lung cancer. The COLT pilot addresses potential issues concerning data collection and provides recommendations for the main COLT trial. Methods: Three retrospective studies were undertaken to compare surgical approaches for lung cancer resection mediastinal mass resection and LVRS. The COLT pilot study was conducted prospectively for 2 months prior to being cut short by COVID-19. Results: 90 lobectomy cases were included in COLT pilot (98.1% data completeness). Rates of minimally invasive surgery for lung cancer were high (75.6%). Post-operative outcomes were similar between robotic and VATS lobectomy with small differences between VATS and open lobectomy, regarding length of stay and pain. This was the first published series on robotic LVRS. Patients undergoing robotic LVRS required less IV morphine post-operatively (13.8mg vs 58.0mg, p=0.026) and were less likely to be admitted to critical care (8.3% vs 70.8%, p=0.001), compared with VATS LVRS. Robotic LVRS was marginally cheaper than VATS LVRS (£5421.63 vs £5695.46) due to reduced length of hospitalisation and critical care stay. Robotic LVRS had a short learning curve; operative time plateaued after 6 cases, similar to VATS LVRS. Introducing robotic mediastinal surgery resulted in significant increase in mediastinal masses being resected by a minimal invasive surgery (20% to 45%). Minimally invasive mediastinal surgery resulted in a shorter length of stay (4 vs 2 vs 2 days, open vs VATS vs robotic, p<0.0001) and less post-operative critical care admissions (88.64% v 27.59%, p <0.0001) than open surgery. Conclusions: Retrospective analysis showed robotic lobectomies are less likely to require critical care admission. Robotic surgery may allow for an increase in rates of minimally invasive surgery, as demonstrated with robotic mediastinal surgery, which is beneficial in terms of length of stay and critical care admissions. Robotic LVRS patients had less pain and were less likely to be admitted to critical care compared to VATS LVRS. Robotic LVRS was at least as cost-effective as VATS LVRS

Development of a knowledge management system for the NOMAD instrument onboard the ExoMars TGO spacecraft

Purpose This paper aims to describe the development of a knowledge management system (KMS) for the Nadir and Occultation for Mars Discovery (NOMAD) instrument on board the ESA/Roscosmos 2016 ExoMars Trace Gas Orbiter (TGO) spacecraft. The KMS collects knowledge acquired during the engineering process that involved over 30 project partners. In addition to the documentation and technical data (explicit knowledge), a dedicated effort was made to collect the gained experience (tacit knowledge) that is crucial for the operational phase of the TGO mission and also for future projects. The system is now in service and provides valuable information for the scientists and engineers working with NOMAD Design/methodology/approach The NOMAD KMS was built around six areas: official documentation, technical specifications and test results, lessons learned, management data (proposals, deliverables, progress reports and minutes of meetings), picture files and movie files. Today, the KMS contains 110 GB of data spread over 11,000 documents and more than 13,000 media files. A computer-aided design (CAD) library contains a model of the full instrument as well as exported sub-parts in different formats. A context search engine for both documents and media files was implemented. Findings The conceived KMS design is basic, flexible and very robust. It can be adapted to future projects of a similar size. Practical implications The paper provides practical guidelines on how to retain the knowledge from a larger aerospace project. The KMS tool presented here works offline, requires no maintenance and conforms to data protection standards. Originality/value This paper shows how knowledge management requirements for space missions can be fulfilled. The paper demonstrates how to transform the large collection of project data into a useful tool and how to address usability aspects

Outcomes of acute type A aortic dissection repair: Daytime versus nighttime.

ObjectiveWe sought to report our experience of repairing acute type A aortic dissection (ATAAD) over 21 years during in-hours versus out-of-hours before and after the establishment of specialized aortic service and rota.MethodsA retrospective analysis of all patients who had ATAAD repair between November 1998 and December 2019 in our center. In-hours were defined as 08:00 to 19:59 hours and out of hours were defined as 20:00 to 07:59 hours.ResultsA total of 286 patients underwent repair of ATAAD. Eighty operations took place during the prerota period (43 operations in hours, 37 out of hours) and 206 operations during the specialized rota period (110 in hours, 96 out of hours). There was no difference in 30-day mortality between the in-hours and out-of-hours groups in either the prerota (23.3% vs 32.4%; P = .36) or specialized rota periods (11.6% vs 11.5%; P = .94). Mean number of cases per year increased by 83% between the prerota and specialized rota periods. Thirty-day mortality reduced in both the in-hours (23.3% vs 11.6%) and out-of-hours (32.4% vs 11.5%) groups since introduction of the specialized aortic rota.ConclusionsOutcomes in repair of ATAAD during in-hours and out-of-hours periods are similar when operated on in a specialized unit with a dedicated aortic team. This emphasizes the current global trend of service centralization without particular attention to time of day to operate on such critical cohort patients

Molecular diversity of anthracnose pathogen populations associated with UK strawberry production suggests multiple introductions of three different Colletotrichum species.

Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production

Targeted Isolation of Antibodies Directed against Major Sites of SIV Env Vulnerability

The simian immunodeficiency virus (SIV) challenge model of lentiviral infection is often used as a model to human immunodeficiency virus type 1 (HIV-1) for studying vaccine mediated and immune correlates of protection. However, knowledge of the structure of the SIV envelope (Env) glycoprotein is limited, as is knowledge of binding specificity, function and potential efficacy of SIV antibody responses. In this study we describe the use of a competitive probe binding sort strategy as well as scaffolded probes for targeted isolation of SIV Env-specific monoclonal antibodies (mAbs). We isolated nearly 70 SIV-specific mAbs directed against major sites of SIV Env vulnerability analogous to broadly neutralizing antibody (bnAb) targets of HIV-1, namely, the CD4 binding site (CD4bs), CD4-induced (CD4i)-site, peptide epitopes in variable loops 1, 2 and 3 (V1, V2, V3) and potentially glycan targets of SIV Env. The range of SIV mAbs isolated includes those exhibiting varying degrees of neutralization breadth and potency as well as others that demonstrated binding but not neutralization. Several SIV mAbs displayed broad and potent neutralization of a diverse panel of 20 SIV viral isolates with some also neutralizing HIV-27312A. This extensive panel of SIV mAbs will facilitate more effective use of the SIV non-human primate (NHP) model for understanding the variables in development of a HIV vaccine or immunotherapy

Determining the nanoflare heating frequency of an X-ray Bright Point observed by MaGIXS

Nanoflares are thought to be one of the prime candidates that can heat the solar corona to its multi-million kelvin temperature. Individual nanoflares are difficult to detect with the present generation instruments, however their presence can be inferred by comparing simulated nanoflare-heated plasma emissions with the observed emission. Using HYDRAD coronal loop simulations, we model the emission from an X-ray bright point (XBP) observed by the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS), along with nearest-available observations from the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO) and X-Ray Telescope (XRT) onboard Hinode observatory. The length and magnetic field strength of the coronal loops are derived from the linear-force-free extrapolation of the observed photospheric magnetogram by Helioseismic and Magnetic Imager (HMI) onboard SDO. Each loop is assumed to be heated by random nanoflares, whose magnitude and frequency are determined by the loop length and magnetic field strength. The simulation results are then compared and matched against the measured intensity from AIA, XRT, and MaGIXS. Our model results indicate the observed emissions from the XBP under study could be well matched by a distribution of nanoflares with average delay times 1500 s to 3000 s, which suggest that the heating is dominated by high-frequency events. Further, we demonstrate the high sensitivity of MaGIXS and XRT to diagnose the heating frequency using this method, while AIA passbands are found to be the least sensitive.Comment: Accepted for publication in the Astrophysical Journal (ApJ