Modelling advanced reforming of bio-compounds for hydrogen production

In the efforts to decarbonise the energy system, there has been a great deal of interest in the potential of hydrogen (H2) as a versatile, low carbon energy vector. To support rising demand for hydrogen in existing and new applications, it will be necessary to find cost-effective routes for hydrogen production at scale. Recent research has identified new methods to optimise the steam reforming process as a means to achieve this. These include chemical looping, in which a metal oxide provides an unmixed source of oxygen directly into the reforming reactor, to enable autothermal reactor operation. Other work has considered sorption enhancement, in which solid CO2 sorbents provide in situ CO2 capture, enhancing product purity and improving process yields. Another branch of research considers the use of bioenergy feedstocks to reduce carbon intensity. One promising route is the fast pyrolysis of bioenergy feedstocks to produce bio-oils, followed by steam reforming. This route could combine the benefits of a flexible bio-based supply chain with those of the steam reforming process, including its thermal efficiency and cost-effectiveness. This thesis brings together these two branches of process development, to consider the feasibility and benefits of using bio-oil in advanced reforming processes, to produce hydrogen with low, or negative, carbon emissions. A thermodynamic evaluation is first presented, to determine the thermodynamic feasibility of different bio-oil reforming technologies, including conventional steam reforming (C-SR), sorption-enhanced steam reforming (SE-SR), chemical looping steam reforming (CLSR) and sorption-enhanced chemical looping steam reforming (SE-CLSR). When these benefits of chemical looping and sorption enhancement are combined, the resulting SE-CLSR process is autothermal, with reduced risk of carbon deposition, reduced H2 purification requirements, and the potential for readily separated CO2. A techno-economic evaluation is carried out on the viability of SE-CLSR and C-SR and with CO2 capture (C-SR-CCS), using heat and material balances derived from process models in Aspen Plus. C-SR-CCS and SE-CLSR produce hydrogen in a similar price range, of 3.8 to 4.6 $kgH2-1. Both processes have similar operating costs, but SE-CLSR has a lower capital cost, leading to a marginally lower hydrogen cost. SE-CLSR has certain other advantages, such as the elimination of fossil-based energy, and therefore increased potential for net negative emissions. Cost of carbon avoided, based on direct process emissions, including negative emissions, is estimated to be in the range of 95 to 105$ tCO2-1, similar to bioenergy with CCS (BECCS) in other industries. The analysis identified that a key process stage is simultaneous reduction-calcination, during which the reactor bed undergoes several important functions required to complete the SE-CLSR cycle. These include sorbent regeneration, reduction of the oxygen transfer material, and bed cooling. In Chapter 7, a dynamic packed bed reactor model is created in gPROMS Modelbuilder™ 4.1.0. This confirms that simultaneous reduction-calcination in a nickel-based system is feasible in principle. However, certain design and operating strategies will be required to manage the many complex and interacting factors in the system, including CO2 equilibrium pressure, CO2 product purity, and the relative speeds of reduction and calcination fronts. Future models of the entire SE-CLSR process will also require the derivation of bio-oil steam reforming kinetics. Chapter 7 details an experimental study on acetic acid, a major constituent of bio-oil that is commonly used as a model compound. A kinetic model is proposed, using a simplified reaction scheme comprised of acetic acid steam reforming, acetic acid decomposition to CO, and the water gas shift reaction. This model is subsequently used to compare steam methane reforming to bio-oil steam reforming in a low-pressure industrial-scale reactor bed. This identifies that the relatively slow kinetics of acetic acid steam reforming are another important aspect for consideration. Taken together, the above analyses provide a high-level assessment of the advanced reforming of bio-oils. In principle, SE-CLSR could offer certain technical and economic advantages compared to conventional steam reforming, and could offer a competitive route to hydrogen production with negative emissions. However, this is contingent upon several priority areas identified for process development

Reducing inappropriate polypharmacy: the process of deprescribing

Inappropriate polypharmacy, especially in older people, imposes a substantial burden of adverse drug events, ill health, disability, hospitalization, and even death. The single most important predictor of inappropriate prescribing and risk of adverse drug events in older patients is the number of prescribed drugs. Deprescribing is the process of tapering or stopping drugs, aimed at minimizing polypharmacy and improving patient outcomes. Evidence of efficacy for deprescribing is emerging from randomized trials and observational studies. A deprescribing protocol is proposed comprising 5 steps: (1) ascertain all drugs the patient is currently taking and the reasons for each one; (2) consider overall risk of drug-induced harm in individual patients in determining the required intensity of deprescribing intervention; (3) assess each drug in regard to its current or future benefit potential compared with current or future harm or burden potential; (4) prioritize drugs for discontinuation that have the lowest benefit-harm ratio and lowest likelihood of adverse withdrawal reactions or disease rebound syndromes; and (5) implement a discontinuation regimen and monitor patients closely for improvement in outcomes or onset of adverse effects. Whereas patient and prescriber barriers to deprescribing exist, resources and strategies are available that facilitate deliberate yet judicious deprescribing and deserve wider application

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Expanding the 3 Wishes Project for compassionate end-of-life care: a qualitative evaluation of local adaptations.

BackgroundThe 3 Wishes Project (3WP) is an end-of-life program that honors the dignity of dying patients by fostering meaningful connections among patients, families, and clinicians. Since 2013, it has become embedded in the culture of end-of-life care in over 20 ICUs across North America. The purpose of the current study is to describe the variation in implementation of 3WP across sites, in order to ascertain which factors facilitated multicenter implementation, which factors remain consistent across sites, and which may be adapted to suit local needs.MethodsUsing the methodology of qualitative description, we collected interview and focus group data from 85 clinicians who participated in the successful initiation and sustainment of 3WP in 9 ICUs. We describe the transition between different models of 3WP implementation, from core clinical program to the incorporation of various research activities. We describe various sources of financial and in-kind resources accessed to support the program.ResultsBeyond sharing a common goal of improving end-of-life care, sites varied considerably in organizational context, staff complement, and resources. Despite these differences, the program was successfully implemented at each site and eventually evolved from a clinical or research intervention to a general approach to end-of-life care. Key to this success was flexibility and the empowerment of frontline staff to tailor the program to address identified needs with available resources. This adaptability was fueled by cross-pollination of ideas within and outside of each site, resulting in the establishment of a network of like-minded individuals with a shared purpose.ConclusionsThe successful initiation and sustainment of 3WP relied on local adaptations to suit organizational needs and resources. The semi-structured nature of the program facilitated these adaptations, encouraged creative and important ways of relating within local clinical cultures, and reinforced the main tenet of the program: meaningful human connection at the end of life. Local adaptations also encouraged a team approach to care, supplementing the typical patient-clinician dyad by explicitly empowering the healthcare team to collectively recognize and respond to the needs of dying patients, families, and each other.Trial registrationNCT04147169 , retrospectively registered with clinicaltrials.gov on October 31, 2019