On the use of plume models to estimate the flux in volcanic gas plumes.

Many of the standard volcanic gas flux measurement approaches involve absorption spectroscopy in combination with wind speed measurements. Here, we present a new method using video images of volcanic plumes to measure the speed of convective structures combined with classical plume theory to estimate volcanic fluxes. We apply the method to a nearly vertical gas plume at Villarrica Volcano, Chile, and a wind-blown gas plume at Mount Etna, Italy. Our estimates of the gas fluxes are consistent in magnitude with previous reported fluxes obtained by spectroscopy and electrochemical sensors for these volcanoes. Compared to conventional gas flux measurement techniques focusing on SO2, our new model also has the potential to be used for sulfur-poor plumes in hydrothermal systems because it estimates the H2O flux

On the use of plume models to estimate the flux in volcanic gas plumes.

Many of the standard volcanic gas flux measurement approaches involve absorption spectroscopy in combination with wind speed measurements. Here, we present a new method using video images of volcanic plumes to measure the speed of convective structures combined with classical plume theory to estimate volcanic fluxes. We apply the method to a nearly vertical gas plume at Villarrica Volcano, Chile, and a wind-blown gas plume at Mount Etna, Italy. Our estimates of the gas fluxes are consistent in magnitude with previous reported fluxes obtained by spectroscopy and electrochemical sensors for these volcanoes. Compared to conventional gas flux measurement techniques focusing on SO2, our new model also has the potential to be used for sulfur-poor plumes in hydrothermal systems because it estimates the H2O flux

Stokes settling and particle-laden plumes: implications for deep-sea mining and volcanic eruption plumes

Turbulent buoyant plumes moving through density stratified environments transport large volumes of fluid vertically. Eventually, the fluid reaches its neutral buoyancy level at which it intrudes into the environment. For single-phase plume, the well known theory of Morton, Taylor and Turner [1] describes the height of the intrusion with great accuracy. However, in multiphase plumes, such as descending particle plumes formed from the surface vessel during deep- sea mining operations, or ascending volcanic plumes, consisting of hot gas and dense ash particles, the sedimentation of particles can change the buoyancy of the fluid very significantly. Even if the plume speed far exceeds the sedimentation speed, the ultimate intrusion height of the fluid may be significantly affected by particle sedimentation. We explore this process, illustrating the phenomena with a series of analogue experiments and some simple modelling, and we discuss the applications in helping to quantify some environmental impacts of deep-sea mining and in helping to assess the eruption conditions leading to the formation of large laterally spreading ash clouds in the atmosphere

Thermodynamic stability of alkali metal/zinc double-cation borohydrides at low temperatures

We study the thermodynamic stability at low temperatures of a series of alkali metal/zinc double-cation borohydrides, including LiZn(BH$_4$)$_3$, LiZn$_2$(BH$_4$)$_5$, NaZn(BH$_4$)$_3$, NaZn$_2$(BH$_4$)$_5$, KZn(BH$_4$)$_3$, and KZn$_2$(BH$_4$)$_5$. While LiZn$_2$(BH$_4$)$_5$, NaZn(BH$_4$)$_3$, NaZn$_2$(BH$_4$)$_5$ and KZn(BH$_4$)$_3$ were recently synthesized, LiZn(BH$_4$)$_3$ and KZn$_2$(BH$_4$)$_5$ are hypothetical compounds. Using the minima-hopping method, we discover two new lowest-energy structures for NaZn(BH$_4$)$_3$ and KZn$_2$(BH$_4$)$_5$ which belong to the $C2/c$ and $P2$ space groups, respectively. These structures are predicted to be both thermodynamically stable and dynamically stable, implying that their existence may be possible. On the other hand, the lowest-energy $P1$ structure of LiZn(BH$_4$)$_3$ is predicted to be unstable, suggesting a possible reason elucidating why this compound has not been experimentally identified. In exploring the low-energy structures of these compounds, we find that their energetic ordering is sensitive to the inclusion of the van der Waals interactions. We also find that a proper treatment of these interactions, e.g., as given by a non-local density functional such as vdW-DF2, is necessary to address the stability of the low-energy structures of these compounds.Comment: Final versio

A qualitative study of experiences of NHS mental healthcare workers during the Covid-19 pandemic.

BackgroundThe Covid-19 pandemic has imposed extraordinary strains on healthcare workers. But, in contrast with acute settings, relatively little attention has been given to those who work in mental health settings. We aimed to characterise the experiences of those working in English NHS secondary mental health services during the first wave of the pandemic.MethodsThe design was a qualitative interview-based study. We conducted semi-structured, remote (telephone or online) interviews with 35 members of staff from NHS secondary (inpatient and community) mental health services in England. Analysis was based on the constant comparative method.ResultsParticipants reported wide-ranging changes in the organisation of secondary mental health care and the nature of work in response to the pandemic, including pausing of all services deemed to be "non-essential", deployment of staff across services to new and unfamiliar roles, and moves to remote working. The quality of participants' working life was impaired by increasing levels of daily challenge associated with trying to provide care in trying and constrained circumstances, the problems of forging new ways of working remotely, and constraints on ability to access informal support. Participants were confronted with difficult dilemmas relating to clinical decision-making, prioritisation of care, and compromises in ability to perform the therapeutic function of their roles. Other dilemmas centred on trying to balance the risks of controlling infection with the need for human contact. Many reported features of moral injury linked to their perceived failures in providing the quality or level of care that they felt service users needed. They sometimes sought to compensate for deficits in care through increased advocacy, taking on additional tasks, or making exceptions, but this led to further personal strain. Many experienced feelings of grief, helplessness, isolation, distress, and burnout. These problems were compounded by sometimes poor communication about service changes and by staff feeling that they could not take time off because of the potential impact on others. Some reported feeling poorly supported by organisations.ConclusionsMental health workers faced multiple adversities during the pandemic that were highly consequential for their wellbeing. These findings can help in identifying targets for support

Remote care for mental health:qualitative study with service users, carers and staff during the COVID-19 pandemic

Objectives: To explore the experiences of service users, carers and staff seeking or providing secondary mental health services during the COVID-19 pandemic. Design: Qualitative interview study, co-designed with mental health service users and carers. Methods: We conducted semi-structured, telephone or online interviews with a purposively constructed sample; a lived experience researcher conducted and analysed interviews with service users. Analysis was based on the constant comparison method. Setting: NHS secondary mental health services in England between June and August 2020. Participants: Of 65 participants, 20 had either accessed or needed to access English secondary mental healthcare during the pandemic; 10 were carers of people with mental health difficulties; 35 were members of staff working in NHS secondary mental health services during the pandemic. Results: Experiences of remote care were mixed. Some service users valued the convenience of remote methods in the context of maintaining contact with familiar clinicians. Most participants commented that a lack of non-verbal cues and the loss of a therapeutic ‘safe space’ challenged therapeutic relationship building, assessments, and identification of deteriorating mental wellbeing. Some carers felt excluded from remote meetings and concerned that assessments were incomplete without their input. Like service users, remote methods posed challenges for clinicians who reported uncertainty about technical options and a lack of training. All groups expressed concern about intersectionality exacerbating inequalities and the exclusion of some service user groups if alternatives to remote care are lost. Conclusions: Though remote mental healthcare is likely to become increasingly widespread in secondary mental health services, our findings highlight the continued importance of a tailored, personal approach to decision-making in this area. Further research should focus on which types of consultations best suit face-to-face interaction, and for whom and why, and which can be provided remotely and by which medium.This research was funded by The Healthcare Improvement Studies Institute (THIS Institute), University of Cambridge. THIS Institute is supported by the Health Foundation, an independent charity committed to bringing about better health and healthcare for people in the UK. Grant number not applicable. All contracted parties contributed to the study under agreements through the same funding. PBJ is supported by the NIHR Applied Research Collaboration East of England and by RP-PG-0161-20003. Mary Dixon-Woods is an NIHR Senior Investigator (NF-SI-0617-10026)

Qualitative study of candidacy and access to secondary mental health services during the COVID-19 pandemic.

Funder: The Health FoundationCandidacy, a construct describing how people's eligibility for care is negotiated between themselves and services, has received limited attention in the context of mental health care. In addition, candidacy research has only rarely studied the views of carers and health professionals. In this article, we use concepts relating to candidacy to enable a theoretically informed examination of experiences of access to secondary mental health services during the first wave of the COVID-19 pandemic in England. We report a qualitative study of the views and experiences of service users, carers, and healthcare professionals. Analysis of 65 in-depth interviews was based on the constant comparative method. We found that wide-ranging service changes designed to address the imperatives of the pandemic were highly consequential for people's candidacy. Macro-level changes, including increased emphasis on crisis and risk management and adapted risk assessment systems, produced effects that went far beyond restrictions in the availability of services: they profoundly re-structured service users' identification of their own candidacy, including perceptions of what counted as a problem worthy of attention and whether they as individuals needed, deserved, and were entitled to care. Services became less permeable, such that finding a point of entry to those services that remained open required more work of service users and carers. Healthcare professionals were routinely confronted by complex decisions and ethical dilemmas about provision of care, and their implicit judgements about access may have important implications for equity. Many of the challenges of access exposed by the pandemic related to pre-existing resource deficits and institutional weaknesses in care for people living with mental health difficulties. Overall, these findings affirm the value of the construct of candidacy for explaining access to mental healthcare, but also enable deepened understanding of the specific features of candidacy, offering enduring learning and implications for policy and practice.This project was funded by THIS Institute’s grant from the Health Foundation. The Health Foundation is an independent charity committed to bringing about better health and health care for people in the UK. All contracted parties contributed to the study under agreements through the same funding. PBJ is supported by the NIHR Applied Research Collaboration East of England and by RP-PG-0161-20003. Mary Dixon-Woods is an NIHR Senior Investigator (NF-SI-0617-10026). The views expressed in this article are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care

Platinum(IV)-azido monocarboxylato complexes are photocytotoxic under irradiation with visible light

Complexes trans,trans,trans-[Pt(N-3)(2)(OH)(OCOR)(py)(2)] where py = pyridine and where OCOR = succinate (1); 4-oxo-4-propoxybutanoate (2) and N-methylisatoate (3) have been synthesized by derivation of trans, trans,trans-[Pt(OH)(2)(N-3)(2)(py)(2)] (4) and characterised by NMR and EPR spectroscopy, ESI-MS and X-ray crystallography. Irradiation of 1-3 with green (517 nm) light initiated photoreduction to Pt(II) and release of the axial ligands at a 3-fold faster rate than for 4. TD-DFT calculations showed dissociative transitions at longer wavelengths for 1 compared to 4. Complexes 1 and 2 showed greater photocytotoxicity than 4 when irradiated with 420 nm light (A2780 cell line IC50 values: 2.7 and 3.7 mu M) and complex 2 was particularly active towards the cisplatin-resistant cell line A2780cis (IC50 3.7 mu M). Unlike 4, complexes 1-3 were phototoxic under green light irradiation (517 nm), with minimal toxicity in the dark. A pK(a)(H2O) of 5.13 for the free carboxylate group was determined for 1, corresponding to an overall negative charge during biological experiments, which crucially, did not appear to impede cellular accumulation and photocytotoxicity.NF thanks the Wellcome Trust (201406/Z/16/Z); Cancer Research UK (CR-UK) grant number C5255/A18085 through the Cancer Research UK Oxford Centre and the John Fell Fund for funding. NF thanks Profs. Stephen Faulkner for support. PJS and NF thank the EPSRC (for grant EP/P030572/1 and studentship for ES), PJS also thanks the ERC (grant 247450). L. S. performed this work under the Severo Ochoa Centres of Excellence Programme run by the Spanish State Research Agency, grant no. CEX2018-000867-S (DIPC). L. S. also thanks the Spanish Multi-MetDrugs network (RED2018-102471-T) for fruitful discussio