23 research outputs found
AWG-DBR-based WDM transmitter fabricated in an InP generic foundry platform
We report a novel narrow-linewidth WDM transmitter operating at 10 Gbps per transmission channel with 275 kHz optical linewidth. The device, which integrates an AWG-based laser using selective DBR-mirrors with a Mach-Zehnder modulator array, has been fabricated in a multi-project wafer run in a generic InP-based foundry process.</p
Resuscitation with pre-hospital blood products in adults with trauma-related haemorrhagic shock:the RePHILL RCT
Background:âThe treatment of traumatic haemorrhagic shock has been transformed through better haemorrhage control, use of tranexamic acid and use of blood products. The improved survival seen from these strategies has stimulated an interest in pre-hospital transfusion.Objectives:âTo determine if the clinical effectiveness of resuscitation with red blood cells and lyophilised plasma was superior to 0.9% saline for improving tissue perfusion and reducing mortality in adults with haemorrhagic shock following major trauma.Design:âA multi-centre, allocation concealed, open-label, parallel group, randomised controlled trial (with internal pilot).Setting:âThe trial was conducted in four civilian pre-hospital critical care services who operated within the National Health Service (NHS) England Major Trauma Networks.Participants:âAdults (aged â„16 years) who had sustained traumatic injuries, were attended by a pre-hospital emergency medical team and were hypotensive (systolic blood pressure <90 mmHg or absence of radial pulse) as a consequence of traumatic haemorrhage were eligible for inclusion. The exclusion criteria were known or apparently <16 years, blood administered on scene prior to the arrival of the RePHILL team, traumatic cardiac arrest where (1) the arrest occurred prior to arrival of the team and/or (2) the primary cause is not hypovolaemia, refusal of blood product administration, known Jehovahâs Witness, pregnancy, isolated head injury without evidence of external haemorrhage, prisoners in the custody of HM Prison and Probation Service.Interventions:âParticipants were randomised to receive up to either two units each of red blood cells and lyophilised plasma or up to 1âL 0.9% saline. Treatment was administered through the intravenous or intraosseous route.Main outcome measures:âThe primary outcome was a composite of episode mortality and/or impaired lactate clearance. The secondary outcomes included the individual components of the primary outcome.Results:âFrom 6 December 2016 to 2 January 2021, pre-hospital medical teams randomised 432 participants to red blood cell/lyophilised plasma (n = 209) or 0.9% saline (n = 223) out of a target sample size of 490. Most participants were white (62%), males (82%), median age 38 (interquartile range 26 to 58), involved in a road traffic collision (62%) with severe injuries (median injury severity score 36, interquartile range 25 to 50). Prior to randomisation participants had received on average 430 ml crystalloid fluids and tranexamic acid (90%). The primary outcome occurred in 128/199 (64.3%) of participants randomised to red blood cell/lyophilised plasma and 136/210 (64.8%) randomised to 0.9% saline [adjusted risk difference â0.025% (95% confidence interval â9.0% to 9.0%), p = 0.996]. The event rates for the individual components of the primary outcome, episode mortality and lactate clearance were not statistically different between groups [adjusted average differences â3% (â12% to 7%); p = 0.57 and â5% (â14% to 5%), p = 0.33, respectively].Limitations:âRecruitment stopped prematurely due to disruption caused by the COVID-19 pandemic.Future work:âIdentify the characteristics of patients who may benefit from pre-hospital blood products and whether alternative transfusion regimens are superior to standard care.Conclusions:âThe trial did not demonstrate that pre-hospital red blood cell/lyophilised plasma resuscitation was superior to 0.9% saline for trauma-related haemorrhagic shock.Trial registration:âThis trial is registered as ISRCTN62326938.Funding:âThis award was funded by the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation Programme (NIHR award ref: 14/152/14) and is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 2. See the NIHR Funding and Awards website for further award information.<br/
Compact optical comb generator using InP tunable laser and push-pull modulator
We have investigated the suitability of InP-based push-pull modulators to generate flat optical comb spectra. The residual amplitude modulation that was a consequence of driving the modulator well above its design voltage (up to 4V[pi]) is demonstrated to have no adverse effect for the comb generation. We also demonstrate generation of a comb with spacing equal to twice the repetition rate via control of the relative phase of the RF signals
InP-based photonic integration : learning from CMOS
Abstract In the last decades the complexity of InP-based Photonic Integrated Circuits has increased by almost two orders. In this paper past and future developments in Photonic Integration will be discussed
Eye donation from palliative and hospice care contexts: the EDiPPPP mixed-methods study
Background Over 2 million people in the United Kingdom are living with sight loss with costs to the United Kingdom economy reported as ÂŁ4.34 billion annually. Conditions that lead to sight loss and impaired vision can be treated if eye tissue is available for corneal transplantation, reconstructive surgery and research into eye diseases. Supply of eye tissue (only available via eye donation) is currently insufficient to meet demand; therefore, new routes are needed. Hospice and hospital-based Palliative Care Services have been reported as potential donation sources of this tissue. Objectives To: (1) scope the size and clinical characteristics of the potential eye donation population from research sites; (2) map the donation climate of each research site; (3) identify factors that enable or challenge service providers to consider the option of eye donation from a local and national perspective; (4) identify service usersâ views regarding the option of eye donation and the propriety of discussing eye donation; and (5) develop and pilot an empirically based intervention designed to change behaviours in relation to eye donation. Design A 36-month mixed-methods, multicentre study undertaking three work packages. Settings Three hospice care and three hospital-based palliative care services situated in the North, Midlands and the South of England (one service of each type per region). Participants Work package 1 â 105 service providers. Work package 2 â 62 service users, and 156 service providers in the national survey. Work package 3 â 21 expert consultees (patient and public involvement, cross discipline). Data sources Scoping review, retrospective note review, qualitative interviews/focus groups, participant observation, secondary analysis of primary data, national survey, transparent expert consultation. Results Potential: The retrospective notes review demonstrated that of 1199 deceased patientsâ notes, 553 (46%) patients met the criteria for eye donation (56%, n = 337 in hospice care service settings and 36%, n = 216 in hospital palliative care service). Practice: Less than 4% of all cases agreed as eligible for donation had been approached or referred for eye donation. Eye donation is not currently an embedded practice at local and national levels. Perceptions: Service providers were motivated to discuss eye donation but lacked opportunity and capability. Service users were willing and able to hold conversations about eye donation but were not aware of the option and had not had the option discussed with them. Preferences: Service users wanted to be offered the option of eye donation, and service providers wanted bespoke education and training related to eye donation. Evaluation of the developed intervention STEPS â Support Toolkit for Eye donation in Palliative care Settings will follow implementation of the full intervention (expected to begin in October 2022). Limitations Due to the significant impact of the COVID-19 pandemic on clinical sites, partner organisations and national service providers, only two elements of the developed intervention have been pilot tested for proof of concept and the response rate to the national survey was low (8%). Conclusions Significant potential exists for eye donation from hospice care and hospital palliative care services; however, individual and organisational behaviour as well as information system-based changes are needed to maximise this potential. Future work Evaluation of the STEPS â Support Toolkit for Eye donation in Palliative care Settings; Research exploring the wider public knowledge and views regarding eye donation; research exploring the use of language by National Health Service Blood and Transplant-Tissue and Eye Services in their public-facing infographics, communications and campaigns (specifically the use of the term eye donation). Trial registration This trial is registered as ISRCTN14243635: Eye donation from palliative care and hospice care settings. Funding details This project was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (17/49/42) and will be published in full in Health and Social Care Delivery Research; Vol. 11, No. 20. See the NIHR Journals Library website for further project information.
Plain language summary The Royal National Institute of Blind people report that over 2 million people in the United Kingdom are living with sight loss. This number is predicted to double to nearly 4 million by 2050. Conditions that lead to sight loss and impaired vision can be treated if eye tissue is available through, for example corneal transplantation, reconstructive surgery and research into eye diseases. However, the problem is that there is not enough eye tissue available to meet current need. Patients under the care of hospice care services and hospital palliative care services who, due to a cancer diagnosis, are unable to donate other organs or tissues, may be able to donate their eyes. To explore potential for eye donation in these settings, we looked at the clinical notes from patients who died in the previous 2 years to see if they could potentially have been a donor. We also interviewed patients and carers seeking their views regarding âifâ, âwhenâ and âhowâ a conversation about eye donation should take place within end-of-life care planning. We also asked healthcare professionals (via interviews and a national survey) about their views regarding eye donation being part of end-of-life planning, and what they saw as the key barriers to this becoming a routine practice. We found that many patients are eligible for eye donation, but very few are asked about this option, and that patients indicated they wanted this option raised with them so that they could make decisions about donation. A review of patient notes, healthcare professional interviews and survey responses indicate that eye donation is not part of the current routine clinical practice. Our work presents a clear case for a change to current practice so that patients who wish to donate are offered this opportunity as a part of routine end-of-life care, and that changes in the current practice require specific training initiatives and institutional support.
Scientific summary Background Globally, the estimated number of visually impaired people is reported by the World Health Organization (WHO) to be 285 million, with 39 million individuals recorded as blind, and 246 million as having low vision. According to Pascolini and Mariotti, over 10 million of those reported as blind have bilateral corneal blindness, which could be restored with a corneal transplant. However, these individuals do not have access to sight-saving and sight-restoring transplantation surgery owing to a shortfall in supply of tissue (cornea and sclera) that is only available via eye donation (ED). According to the Royal National Institute of Blind (RNIB), over 2 million people in the UK have sight loss caused by conditions such as keratoconus and Fuchsâ corneal dystrophy, which can be treated if eye tissue is available (e.g. by corneal transplantation and reconstructive surgery). Eye tissue is also needed for research into a wide variety of diseases, for example, endothelial failure post cataract surgery. The RNIB reports that approximately 5000 corneal transplants are required annually in the UK to address disease and injury resulting in sight loss, with costs to the UK economy (through unpaid carer burden and reduced employment rates) reported as ÂŁ4.34 billion annually. Critically, this organisation predicts that by 2050, the number of people with sight loss will double to nearly 4 million in the UK mainly owing to an aging population. It is, therefore, imperative that the tissue needed to intervene in these conditions and to support research into the causes and treatment of eye disease is available. The National Health Services Blood and Transplant (NHSBT) Tissue and Eye Services (TES) Bank in Speke, Liverpool (who supply most eyes for UK surgery) aim to achieve a weekly stock of 350 eyes so that they can provide 70 eyes every working day for treatment or research. From April 2021 to March 2022, donation of eyes from all sources (solid organ donation, tissue donation) generated 4555 eyes from 2286 donors equating to only 13 eyes per day and 88 eyes available per week. Significantly, the actual number of people waiting for a corneal transplant is difficult to confirm, as there is no centralised waiting list for patients who need a corneal transplant (unlike solid organ donation). A further pressure on the nationally reported donation rate of 4555 eyes is that approximately 30% will be discarded due to infection/viruses, with supply further compromised by a 28-day limit to storage requiring disposal of tissue thereafter. Therefore, as the current supply of eye tissue is insufficient to meet the demand, new routes of supply are needed. As hospice care (HC) and hospital-based palliative care (HPC) services have been reported as potential donation sources, the ED from palliative and hospice care contexts: investigating potential, practice, preference and perceptions (EDiPPPP) study investigated the potential of these locations to meet the current supply deficits. Research questions and study objectives Research Question (RQ1a): Potential â What is the potential for ED in HPC services and HC services? RQ1b: What consequences will any increase in ED from these settings have for NHSBT-TES in relation to resources/infrastructure/logistics? Objective 1: To scope the size and clinical characteristics of the potential ED population from research sites. Objective 2: To map the donation climate of each research site via a systematic assessment tool: the Rapid Assessment of hospital Procurement barriers in Donation (RAPiD). RQ2: Practice, Preference and Perceptions â What system-based/attitudinal and educational barriers/facilitators to ED influence the identification and referral of potential eye donors in clinical settings, and the embedding of ED in end-of-life care (EoLC) planning? Objective 3: Identify factors (attitudinal, behavioural) that enable or challenge service providers to consider and propose the option of ED as part of EoLC planning from a local and national perspective. Objective 4: Identify service usersâ views regarding the option of ED and the propriety of discussing ED as part of admission procedures or as part of EoLC-planning conversations. RQ3: What behaviour change strategies will be effective in increasing ED across the community of service providers and service users within HPC and HC? Objective 5: Develop an empirically based theoretically informed intervention designed to change behaviours in relation to the identification, approach/request and referral of patients from HPC and HC for ED. Methods Eye donation from palliative and hospice care contexts: investigating potential, practice, preference and perceptions was structured in line with the six steps in quality intervention development (6SQuID) framework. Study design used mixed methods, applying theoretical perspectives and intervention mapping methodologies to deliver three interlinked and developmental work packages (WP). Data sources Literature review, retrospective note review (WP1), interviews/focus groups (WP1 and 2), participant observation (WP1), secondary analysis of primary data (WP2), national survey (WP2), transparent expert consultation (WP3). Participants Work package 1 â 105 healthcare professionals (HCPs) participated in interviews or focus groups. WP2 â 62 service users participated in interviews, 156 service providers participated in the national survey. WP3 â 21 expert consultees [patient and public involvement (PPI), cross-discipline HCP, stakeholder groups] participated in the transparent expert consultation (TEC). Data collection sites Three HC and three HPC services in the North, Midlands and the South of England (one of each service type in each region, for a total of two sites per region); online survey (UK). Data analysis Interviews and focus groups: qualitative content analysis, following the five-level qualitative data analysis (QDA) framework. Survey data: descriptive statistics for closed questions, qualitative content analysis for free-text questions. Results and findings The retrospective note review (WP1) indicated significant potential for ED across HC and HPC settings. Of the 1199 deceased patient case notes, 46% (n = 553) were agreed as being eligible for referral for ED [in HC settings 56% (n = 337) of cases and in HPC 36% (n = 216) of the cases were agreed as eligible]. Twenty-four per cent (n = 289) of all the cases were agreed as ineligible. In <4% of all cases agreed as eligible, there was an approach or referral to the retrieving organisation (e.g. NHSBT-TES) recorded, indicating very low levels of ED-related practice at the study sites. Findings from interviews with service providers indicated that HCPs were generally favourable towards ED, perceiving it as worthwhile and something that should be discussed with patients and carers. Most participants indicated support for raising the option of ED, willingness to do so and a preference for discussion during EoLC planning. While participants indicated beliefs that ED is worthwhile, in most cases, neither ED discussions nor referrals were reported when participants were asked about this, and the majority indicated that they never, or hardly ever, initiated discussions about ED with their patients or family members (ED was usually only discussed âifâ the topic was raised by relatives). Most HCP respondents to the national survey indicated awareness of ED as an option for EoLC patients, but that this was not currently embedded in routine practice in their clinical setting. Furthermore, almost half of survey respondents indicated that their service did not actively encourage the option of ED being discussed with patients and/or their family members, and staff within clinical settings did not routinely discuss ED in team meetings. Service providersâ reluctance to raise the issue of ED was linked explicitly by participants to gaps in knowledge around related processes (including eligibility criteria and processes for referral), resulting in a lack of confidence to initiate donation discussions. Over half of participants had no formal training regarding ED, and of those who had, the majority completed this more than 24 months prior to participation. Interview and survey data indicated a lack of training and education aimed at HCPs in both HC and HPC services. Findings from all data collection sources involving service providers indicated that most participants do not actively raise the option of ED with patients or family members and that concerns exist regarding the potential impact on patients and/or family members of discussing ED. Responses indicate that ED is often not included in local written clinical guidance, information for patients and families or admission documentation. Further investigation of policy documentation and information resources at partner sites indicated widespread lack of clinical guidance and policy to assist HCPs in implementing and embedding ED in routine clinical practice. Findings from interviews with patients and carer (WP2) indicated positive views towards ED, even where there was reluctance or uncertainty about choosing the option for themselves or family members. Most patients and carers were not aware of ED as an option for themselves or their loved ones, and they believed that a patient with a cancer diagnosis could not be an eye donor. Findings indicate that patients are willing and able to be asked about their preferences regarding ED, with no patient or carer respondents indicating that the topic would be too distressing if raised appropriately. Almost all patient and carer participants expressed a clear preference that information about ED should be made available to patients and their families by HCPs early in the process. Participants acknowledge that ED is a sensitive issue, but most expressed views compatible with an expectation that HCPs would have the skills (communication, empathy, judgement) to facilitate a discussion. Both service users and service providers indicated that the issue of ED is best raised early in patientsâ dying trajectory (as patients transition from active to palliative care) or when other end-of-life planning topics are being discussed (e.g. resuscitation). All participants agreed that a judgement as to when to introduce the topic must be based on the patients physical, emotional and cognitive situation and that these issues should be assessed by HCPs before raising the issue. Patients were more concerned about how this topic would be raised than when it would be raised. Most patient participants were of the view that their wishes should take priority and that family membersâ views should not overrule patient wishes regarding ED unless there was no statement of wishes given by the patient prior to death. Conclusions In view of the predicted increase in the need for eye tissue, it is essential that the potential for ED demonstrated by the EDiPPPP study is realised, and that the option of ED is routinely raised with patients and family members as part of EoLC planning. This would give patients the opportunity to fulfil what may be a lifelong wish to be a donor and increase the supply of tissue for sight-saving and sight-restoring transplantation and medical research. The integration of the three work packages has facilitated a systematic, detailed and robust understanding of current practice. This research draws on multiple perspectives, validating the selection of methodology, epistemology and theory underpinning EDiPPPP study design. The study commenced with planning supported by the six steps in quality intervention development (6SQuID) framework and concluded with development of a complex intervention, the Support Toolkit for Eye donation in Palliative care Settings (STEPS). The study has thus facilitated the clarification of key issues contributing to low levels of supply of eye tissue and produced an empirically based, theoretically informed complex intervention for implementation by national services (NHSBT-TES). The EDiPPPP project, therefore, represents a significant empirical and strategic contribution to addressing the problem of eye tissue undersupply at a national level. Specific implications for healthcare practice and service development are given below. Implications for service development In view of the significant potential for ED in HC settings, it is essential that the option of ED is routinely raised with patients and family members if this potential is to be realised. End-of-life planning across clinical settings needs to embrace the range of options available to patients and families regarding donation and enable what may be a lifelong wish to be a donor. NHSBT-TES need to develop accessible, web-based clinical information to support HCPs in the early identification and assessment of all patients admitted to HC and HPC settings against eligibility criteria. The EDiPPPP-developed Eligibility ED Assessment Checklist (EEDAC) represents a ready-to-use tool to facilitate this process. NHSBT-TES need to develop easily accessible web content to answer HCP questions about ED (e.g. eligibility, processes for referral and/or retrieval of eye tissue). Web content needs to be updated regularly to include any changes to donor eligibility determined by NHSBT-TES (e.g. the upper age limit for eye donation, current stock levels). A dedicated link nurse (employed by NHSTB-TES) would facilitate a close partnership with referring sites and act as a resource and ED champion. An evidence-based, centrally generated (by NHSBT-TES) education and training programme needs to be developed that can be rolled out nationally via various modalities (e-learning for health platforms, in-house education teams, donation champions, etc.), thereby ensuring clinicians have up-to-date and regularly updated training to support their practice. Feedback data that inform clinical sites of their referral rates, donation rates and use of donated eye tissue need to be provided so that the motivation to embed ED in routine practice is maintained. Clinical sites need access to the Organ Donor Register (ODR) so that they can establish whether patients have opted out of donation or constrained eyes (indicating that they do not want to donate their eyes). Specific information and guidance regarding implementation of deemed consent legislation is urgently needed by HCPs working in HC settings. Implications for healthcare practice Clinical guidance indicates that HCP practice should embed and normalise the discussion of ED with patients and their families as part of EoLC planning. This is necessary to enable the exploration of donation options, and to support related planning and decision-making within EoLC conversations. Public awareness-raising initiatives are needed that inform patients in HC and HPC services about the option of ED. This can be achieved by ensuring that the information resources recommended in the preceding points are shared with UK-based HC and HPC organisations and their professional bodies (e.g. the Association of Palliative Medicine and Hospice UK). Recommendations for research Evaluation of the STEPS. Research exploring the wider publicsâ knowledge and views regarding ED. Research exploring cultural views regarding Deemed Consent legislation. Research exploring the use of language by NHSBT-TES in their public facing infographics, communications and campaigns (specifically the use of the term Eye Donation). Study registration The EDiPPPP s
A 6 x 30 Gb/s tunable transmitter PIC with low RF crosstalk from an open-access InP foundry
We demonstrate a six-channel tunable optical transmitter photonic integrated circuit (PIC) fabricated in an open-access indium phosphide foundry process. The device monolithically integrates 20 nm tunable lasers and 30 Gb/s Mach-Zehnder modulators, without the use of Bragg gratings or additional quantum wells, to form a compact 4Ă4.5mm2 high-density 6 Ă 30 Gb/s parallel transmitter. It exhibits a capacity density metric of 10Gb/s/mm2 , comparable to state-of-the-art results from literature and low <-50 dB inter-channel radio-frequency crosstalk. With an attractive price point of 7 USD/Gb/s the device can be a low-cost solution for data center interconnect or residential access networks
InP-based optical comb-locked tunable transmitter
We demonstrate a comb-based tunable transmitter with potential to be integrated on a single InP photonic chip. A Nyquist-shaped polarization-multiplexed 16QAM signal with 7.1 bit/s/Hz spectral efficiency is generated and transmitted over 300 km of SMF-2