Electrocardiogram-based mortality prediction in patients with COVID-19 using machine learning.

BACKGROUND AND PURPOSE: The electrocardiogram (ECG) is frequently obtained in the work-up of COVID-19 patients. So far, no study has evaluated whether ECG-based machine learning models have added value to predict in-hospital mortality specifically in COVID-19 patients. METHODS: Using data from the CAPACITY-COVID registry, we studied 882 patients admitted with COVID-19 across seven hospitals in the Netherlands. Raw format 12-lead ECGs recorded within 72 h of admission were studied. With data from five hospitals (n = 634), three models were developed: (a) a logistic regression baseline model using age and sex, (b) a least absolute shrinkage and selection operator (LASSO) model using age, sex and human annotated ECG features, and (c) a pre-trained deep neural network (DNN) using age, sex and the raw ECG waveforms. Data from two hospitals (n = 248) was used for external validation. RESULTS: Performances for models a, b and c were comparable with an area under the receiver operating curve of 0.73 (95% confidence interval [CI] 0.65-0.79), 0.76 (95% CI 0.68-0.82) and 0.77 (95% CI 0.70-0.83) respectively. Predictors of mortality in the LASSO model were age, low QRS voltage, ST depression, premature atrial complexes, sex, increased ventricular rate, and right bundle branch block. CONCLUSION: This study shows that the ECG-based prediction models could be helpful for the initial risk stratification of patients diagnosed with COVID-19, and that several ECG abnormalities are associated with in-hospital all-cause mortality of COVID-19 patients. Moreover, this proof-of-principle study shows that the use of pre-trained DNNs for ECG analysis does not underperform compared with time-consuming manual annotation of ECG features.

Lipegfilgrastim for prophylaxis of chemotherapy-induced neutropenia in Dutch patients.

BACKGROUND: Chemotherapy (CT)-induced neutropenia and febrile neutropenia (FN) can lead to changes in the treatment plan, potentially worsening the cancer outcome. This study evaluated the effect of the glycopegylated granulocyte-colony stimulating factor lipegfilgrastim, used as primary (PP) or secondary prophylaxis (SP), on treatment modifications in adult patients receiving cytotoxic CT with or without biological/targeted therapy (BT) for solid and haematological tumours. METHODS: This phase 4, prospective, observational study was conducted in eight centres in the Netherlands, in 2015-2017. Other study objectives were to characterise the population of cancer patients receiving lipegfilgrastim, to evaluate the incidence of CT-induced neutropenic events, and to assess safety. RESULTS: Of 142 patients, 73.94% had breast cancer and 55.63% received CT in the adjuvant setting. Most patients received lipegfilgrastim as PP (74.65%) and were at low (34.51%) or high risk (39.44%) of FN. CT dose delays were recorded for 22.64% and 36.11% of patients receiving lipegfilgrastim for PP and SP, respectively. CT dose reductions were recorded for 2.11% of patients; no CT dose omissions and one BT dose omission occurred. FN and grade III/IV neutropenia were reported for 5.63% and 9.86% of patients, respectively; associated hospitalisations were rare. The most frequently lipegfilgrastimrelated adverse events (AE) were myalgia, bone pain, and back pain. Serious AEs (55) were reported for 30 (21.13%) patients. There were two deaths, unrelated to lipegfilgrastim administration. CONCLUSION: Administration of lipegfilgrastim in routine clinical practice in the Netherlands results in limited CT/BT dose modifications and low incidence of neutropenic events, with no new safety concerns.

Novel use of repolarization parameters in electrocardiographic imaging to uncover arrhythmogenic substrate.

BACKGROUND: Measuring repolarization characteristics is challenging and has been reserved for experienced physicians. In electrocardiographic imaging (ECGI), activation-recovery interval (ARI) is used as a measure of local cardiac repolarization duration. We hypothesized that repolarization characteristics, such as local electrogram morphology and local and global dispersion of repolarization timing and duration could be of significance in ECGI. OBJECTIVE: To further explore their potential in arrhythmic risk stratification we investigated the use of novel repolarization parameters in ECGI. MATERIALS AND METHODS: We developed and compared methods for T-peak and T-end detection in reconstructed potentials. All methods were validated on annotated reconstructed electrograms (EGMs). Characteristics of the reconstructed EGMs and epicardial substrate maps in IVF patients were analyzed by using data recorded during sinus rhythm. The ECGI data were analyzed for EGM morphology, conduction, and repolarization. RESULTS: We acquired ECGI data from 8 subjects for this study. In all patients we evaluated four repolarization parameters: Repolarization time, T-wave area, Tpeak-Tend interval, and T-wave alternans. Most prominent findings were steep repolarization time gradients in regions with flat EGMs. These regions were also characterized by low T-wave area and large differences in Tpeak-Tend interval. CONCLUSIONS: Measuring novel repolarization parameters in reconstructed electrograms acquired with ECGI is feasible, can be done in a fully automated manner and may provide additional information on underlying arrhythmogenic substrate for risk stratification. Further studies are needed to investigate their potential use and clinical application.

Computational screening of transition metal/p-block hybrid electrocatalysts for CO2 reduction.

Among all the pollutants in the atmosphere, CO2 has the highest impact on global warming, and with the rising levels of this pollutant, studies on developing various technologies to convert CO2 into carbon-neutral fuels and chemicals have become more valuable. In this work, we present a detailed computational study of electrochemical reduction of CO2 reaction (the CO2 RR) to methane and/or methanol over different transition metal-p block catalysts using density functional theory calculations. In addition to the catalyst structure, we studied reaction mechanisms using free energy diagrams that explain the product selectivity with respect to the competing hydrogen evolution reaction. Furthermore, we developed scaling relations between all the active C bound intermediate species with ΔG(CO*) and O bound species with ΔG(OH*) The limiting potential lines with ΔG(OH*) as the descriptor are much less negative compared to UL lines with ΔG(CO*) as the descriptor indicating that catalyst materials following pathways via OH- bound intermediate species require more negative potentials than CO*→ HCO* and CO2 → COOH* steps to convert into products. We developed thermodynamic volcano plots with two descriptors; the CO* and OH* binding free energies and determined the best catalyst material among the initially investigated catalyst materials expecting this plot will provide guidance to the future work on improving the activity of transition metal-p block catalysts for this important reduction reaction.

Size, Composition, and Support-Doping Effects on Oxygen Reduction Activity of Platinum-Alloy and on Non-platinum Metal-Decorated-Graphene Nanocatalysts.

Recent investigations reported in the open literature concerning the functionalization of graphene as a support material for transition metal nanoparticle catalysts have examined isolated systems for their potential Oxygen Reduction Reaction (ORR) activity. In this work we present results which characterize the ability to use functionalized graphene (via dopants B, N) to upshift and downshift the adsorption energy of mono-atomic oxygen, O* (the ORR activity descriptor on ORR Volcano Plots), for various compositions of 4-atom, 7-atom, and 19-atom sub-nanometer binary alloy/intermetallic transition metal nanoparticle catalysts on graphene (TMNP-MDG). Our results show several important and interesting features: (1) that the combination of geometric and electronic effects makes development of simple linear mixing rules for size/composition difficult; (2) that the transition from 4- to 7- to 19-atom TMNP on MDG has pronounced effects on ORR activity for all compositions; (3) that the use of B and N as dopants to modulate the graphene-TMNP electronic structure interaction can cause shifts in the oxygen adsorption energy of 0.5 eV or more; (4) that it might be possible to make specific doped-graphene-Ni x Cu y TMNP systems which fall close to the Volcano Peak for ORR. Our results point to systems which should be investigated experimentally and may improve the viability of future fuel cell or other ORR applications, and provide new paths for future investigations of more detail for TMNP-MDG screening.

Similarities and differences for atomic and diatomic molecule adsorption on the B-5 type sites of the HCP(101Ì 6) surfaces of Co, Os, and Ru from DFT calculations.

The differences in relative adsorption energies for mono-atomic and diatomic prototype species (C,N,O,S,H,CO,NO,SO,CH,NH,H2,O2) relevant to catalytic processes such as Fischer-Tropsch and Ammonia Synthesis chemistry are investigated on the previously un-studied ( 10 1 ¯ 6 ) surface(s) of Co, Os, and Ru. Recent work in the literature has confirmed that catalytically relevant nanoparticles of HCP elements such as Co, Os, and Ru typically possess highly active 'B5' sites; unfortunately many early and extant theory and model-ing treatments of "stepped HCP surfaces" use ad-hoc created steps via manual deletion of atoms from an ideal HCP(0001) slab model. To date the differences in adsorption energies at various B5 step edge types, and any possible trends across the same type of B5 sites on various HCP catalyst species has not been thoroughly characterized. Our work in this manuscript uses the low energy ( 10 1 ¯ 6 ) Miller Index surface of Co, Os, and Ru which exposes 2 distinct and strongly adsorbing step edge sites, the B5B and B5A step edge which have been reported as relevant in the literature for Cobalt nanoparticle catalysis applications. Results from this study should be used to help further understand atomistic processes on the stepped surfaces of catalytically active HCP elements.

Influence of euthanasia method on blood and gill variables in normoxic and hypoxic Gulf killifish Fundulus grandis.

In many experiments, euthanasia, or humane killing, of animals is necessary. Some methods of euthanasia cause death through cessation of respiratory or cardiovascular systems, causing oxygen levels of blood and tissues to drop. For experiments where the goal is to measure the effects of environmental low oxygen (hypoxia), the choice of euthanasia technique, therefore, may confound the results. This study examined the effects of four euthanasia methods commonly used in fish biology (overdose of MS-222, overdose of clove oil, rapid cooling and blunt trauma to the head) on variables known to be altered during hypoxia (haematocrit, plasma cortisol, blood lactate and blood glucose) or reflecting gill damage (trypan blue exclusion) and energetic status (ATP, ADP and ATP:ADP) in Gulf killifish Fundulus grandis after 24 h exposure to well-aerated conditions (normoxia, 7·93 mg O2 l-1 , c. 150 mm Hg or c. 20 kPa) or reduced oxygen levels (0·86 mg O2 l-1 , c. 17 mm Hg or c. 2·2 kPa). Regardless of oxygen treatment, fish euthanized by an overdose of MS-222 had higher haematocrit and lower gill ATP:ADP than fish euthanized by other methods. The effects of 24 h hypoxic exposure on these and other variables, however, were equivalent among methods of euthanasia (i.e. there were no significant interactions between euthanasia method and oxygen treatment). The choice of an appropriate euthanasia method, therefore, will depend upon the magnitude of the treatment effects (e.g. hypoxia) relative to potential artefacts caused by euthanasia on the variables of interest.

The role of initial clinical presentation, comorbidity and treatment in multiple myeloma patients on survival: a detailed population-based cohort study.

PURPOSE: This prospective, observational population-based cohort study was performed to determine overall survival (OS) in multiple myeloma (MM) patients in Friesland, the Netherlands, in the era of novel agents and to analyse the influence of first-line treatment, MM-related end-organ damage and comorbidities at initial presentation on OS. METHODS: Detailed clinical information was obtained from the population-based registry 'HemoBase' during the period January 2005 to January 2013, with a follow-up to January 2014. RESULTS: Overall, the symptomatic MM patients (n = 225) had a median OS of 40 months. In the age categories <65, 65-75 and ≥75 years, 99, 94 and 87% of the patients received treatment, with a median OS of 92, 42 and 31 months, respectively. OS for patients with or without treatment was 43 and 3 months, respectively. In multivariable analysis, risk factors for worse OS were increasing age (<65: reference; 65-75: HRadj. = 2.2 (95% CI 1.3-3.7) and ≥75: HRadj. = 2.8 (95% CI 1.7-4.8); P < 0.001), not receiving initial treatment (HRadj. = 4.0 (95% CI 2.1-7.7); P < 0.001), hypercalcaemia (P < 0.001, HRadj. = 1.7 (95% CI 1.2-2.6), P = 0.006) and impaired renal function (HRadj. = 2.6 (95% CI 1.7-4.0); P < 0.001). CONCLUSIONS: Increasing age, not receiving initial treatment, hypercalcaemia and impaired renal function at initial presentation were independent risk factors for worse OS. Comorbidity according to Charlson comorbidity index score was not an independent variable predicting OS.

Hughes Abdominal Repair Trial (HART) - Abdominal wall closure techniques to reduce the incidence of incisional hernias: study protocol for a randomised controlled trial.

BACKGROUND: Incisional hernias are common complications of midline closure following abdominal surgery and cause significant morbidity, impaired quality of life and increased health care costs. The 'Hughes Repair' combines a standard mass closure with a series of horizontal and two vertical mattress sutures within a single suture. This theoretically distributes the load along the incision length as well as across it. There is evidence to suggest that this technique is as effective as mesh repair for the operative management of incisional hernias; however, no trials have compared the Hughes Repair with standard mass closure for the prevention of incisional hernia formation following a midline incision. METHODS/DESIGN: This is a 1:1 randomised controlled trial comparing two suture techniques for the closure of the midline abdominal wound following surgery for colorectal cancer. Full ethical approval has been gained (Wales REC 3, MREC 12/WA/0374). Eight hundred patients will be randomised from approximately 20 general surgical units within the United Kingdom. Patients undergoing open or laparoscopic (more than a 5-cm midline incision) surgery for colorectal cancer, elective or emergency, are eligible. Patients under the age of 18 years, those having mesh inserted or undergoing musculofascial flap closure of the perineal defect in abdominoperineal wound closure, and those unable to give informed consent will be excluded. Patients will be randomised intraoperatively to either the Hughes Repair or standard mass closure. The primary outcome measure is the incidence of incisional hernias at 1 year as assessed by standardised clinical examination. The secondary outcomes include quality of life patient-reported outcome measures, cost-utility analysis, incidence of complete abdominal wound dehiscence and C-POSSUM scores. The incidence of incisional hernia at 1 year, assessed by computerised tomography, will form a tertiary outcome. DISCUSSION: A feasibility phase has been completed. The results of the study will be used to inform current and future practice and potentially reduce the risk of incisional hernia formation following midline incisions. TRIAL REGISTRATION NUMBER: ISRCTN 25616490 . Registered on 1 January 2012.

Elucidation of Pathways for NO Electroreduction on Pt(111) from First Principles.

The mechanism of nitric oxide electroreduction on Pt(111) is investigated using a combination of first principles calculations and electrokinetic rate theories. Barriers for chemical cleavage of N-O bonds on Pt(111) are found to be inaccessibly high at room temperature, implying that explicit electrochemical steps, along with the aqueous environment, play important roles in the experimentally observed formation of ammonia. Use of explicit water models, and associated determination of potential-dependent barriers based on Bulter-Volmer kinetics, demonstrate that ammonia is produced through a series of water-assisted protonation and bond dissociation steps at modest voltages (<0.3 V). In addition, the analysis sheds light on the poorly understood formation mechanism of nitrous oxide (N2 O) at higher potentials, which suggests that N2 O is not produced through a Langmuir-Hinshelwood mechanism; rather, its formation is facilitated through an Eley-Rideal-type process.

Chiral "pinwheel" heterojunctions self-assembled from C60 and pentacene.

We demonstrate the self-assembly of C60 and pentacene (Pn) molecules into acceptor-donor heterostructures which are well-ordered and--despite the high degree of symmetry of the constituent molecules--chiral. Pn was deposited on Cu(111) to monolayer coverage, producing the random-tiling (R) phase as previously described. Atop R-phase Pn, postdeposited C60 molecules cause rearrangement of the Pn molecules into domains based on chiral supramolecular "pinwheels". These two molecules are the highest-symmetry achiral molecules so far observed to coalesce into chiral heterostructures. Also, the chiral pinwheels (composed of 1 C60 and 6 Pn each) may share Pn molecules in different ways to produce structures with different lattice parameters and degree of chirality. High-resolution scanning tunneling microscopy results and knowledge of adsorption sites allow the determination of these structures to a high degree of confidence. The measurement of chiral angles identical to those predicted is a further demonstration of the accuracy of the models. van der Waals density functional theory calculations reveal that the Pn molecules around each C60 are torsionally flexed around their long molecular axes and that there is charge transfer from C60 to Pn in each pinwheel.

Temporal dynamics in growth and white skeletal muscle composition of the mummichog Fundulus heteroclitus during chronic hypoxia and hyperoxia.

Specific growth rate (G(S) ) and white skeletal muscle composition were measured in the mummichog Fundulus heteroclitus over a period of 28 days at four levels of dissolved oxygen (DO): severe hypoxia (c. 1.2 mg O(2) l(-1) ), moderate hypoxia (3.0 mg O(2) l(-1) ), normoxia (7.1 mg O(2) l(-1) ) and hyperoxia (10.6 mg O(2) l(-1) ). The G(S) was calculated over 0-8, 0-14, 0-28 and 14-28 days, and muscle protein, lactate dehydrogenase (LDH), DNA, RNA and water were measured at 0, 8, 14 and 28 days. Exposure of fish to severe hypoxia was associated with significantly reduced G(S) , lower muscle protein content and lower RNA:DNA compared with other DO treatments. When calculated over the first and second half of the 28 day exposure, however, G(S) of fish in severe hypoxia increased significantly during the second two-week interval, to the same rate as that of normoxic fish. Muscle LDH activity and water content were not significantly affected by DO level. Neither moderate hypoxia nor hyperoxia significantly affected G(S) or any biochemical variable. The results demonstrate that F. heteroclitus can tolerate wide variation in ambient oxygen concentration and, during prolonged exposure to severe hypoxia, shows significant compensation for the initial negative effects on growth. The capacity of F. heteroclitus to grow over a wide range of DO probably contributes to its ability to exploit habitats characterized by marked variation in oxygen availability.

Trends in methanol decomposition on transition metal alloy clusters from scaling and Brønsted-Evans-Polanyi relationships.

A combination of first principles Density Functional Theory calculations and thermochemical scaling relationships are employed to estimate the thermochemistry and kinetics of methanol decomposition on unsupported subnanometer metal clusters. The approach uses binding energies of various atomic and molecular species, determined on the pure metal clusters, to develop scaling relationships that are then further used to estimate the methanol decomposition thermodynamics for a series of pure and bimetallic clusters with four atoms per cluster. Additionally, activation energy barriers are estimated from Brønsted-Evans-Polanyi plots relating transition and final state energies on these clusters. The energetic results are combined with a simple, microkinetically-inspired rate expression to estimate reaction rates as a function of important catalytic descriptors, including the carbon and atomic oxygen binding energies to the clusters. Based on these analyses, several alloy clusters are identified as promising candidates for the methanol decomposition reaction.

Rational Development of Ternary Alloy Electrocatalysts.

Improving the efficiency of electrocatalytic reduction of oxygen represents one of the main challenges for the development of renewable energy technologies. Here, we report the systematic evaluation of Pt-ternary alloys (Pt3(MN)1 with M, N = Fe, Co, or Ni) as electrocatalysts for the oxygen reduction reaction (ORR). We first studied the ternary systems on extended surfaces of polycrystalline thin films to establish the trend of electrocatalytic activities and then applied this knowledge to synthesize ternary alloy nanocatalysts by a solvothermal approach. This study demonstrates that the ternary alloy catalysts can be compelling systems for further advancement of ORR electrocatalysis, reaching higher catalytic activities than bimetallic Pt alloys and improvement factors of up to 4 versus monometallic Pt.

Inter-laboratory study of the in vitro dendritic cell migration assay for identification of contact allergens.

The aim of this study was to investigate the transferability of technology and reproducibility of MUTZ-3 derived Langerhans Cell (MUTZ-LC) migration assay. The protocol was transferred from the NL-lab to two Sens-it-iv project partners (UK-lab, Italy-lab). Intra- and inter-laboratory variation with regards to MUTZ-3 progenitor culture, differentiation to MUTZ-LC, maturation and migration assay were investigated. In the transwell-migration-assay, preferential migration of sensitizer-exposed MUTZ-LC towards CXCL12 was observed (three sensitizers), whereas non-sensitizer-exposed MUTZ-LC only migrated towards CCL5 (two non-sensitizers). Four pre-pro-haptens were also identified by UK-lab. When taking the arbitrary criteria of at least two of three independent repetitions per laboratory having to have a CXCL12/CCL5 ratio>1.1 for classification as a sensitizer, all sensitizers tested in all labs were easily distinguished from all non-sensitizers. The number of repetitions giving false negative or false positive was very low (only 7 out of a total of 54 repetitions), indicating that both intra- and inter-laboratory variation was extremely low. Even though only a few chemicals were tested in this study, we show clearly that the in vitro DC migration assay is transferable between laboratories. The results were consistent between the laboratories, and the dose response data were reproduced in the three laboratories.

Exercise- and hypoxia-induced anaerobic metabolism and recovery: a student laboratory exercise using teleost fish.

Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia), typically resulting in the accumulation of lactate in blood and tissues. Lactate will be cleared over time after the reoxygenation of tissues, eventually returning to control levels. Here, we present a laboratory exercise developed as part of an upper-level vertebrate physiology class that demonstrates the effects of exercise and hypoxia exposure on blood lactate in fish and the subsequent decrease in lactate during recovery. Typically, the results obtained by students demonstrate that both treatments cause significant increases in blood lactate concentrations (two to three times higher than control values) that decrease back to normal values within 3 h of recovery under normoxia. The procedures described are generally applicable to other fish species and provide an alternative to using humans or other mammalian species to investigate anaerobic metabolism.

Vertebrate osmoregulation: a student laboratory exercise using teleost fish.

Here, we describe a laboratory experiment as part of an upper-level vertebrate physiology course for biology majors to investigate the physiological response of vertebrates to osmoregulatory challenges. The experiment involves measuring plasma osmolality and Na+-K+-ATPase activity in gill tissue of teleost fish acclimated to water of differing salinity. We describe results obtained using the widely available goldfish (Carassius auratus) and a common baitfish, the Gulf killifish (Fundulus grandis). The procedures described are generally applicable to other fish species, and they provide an alternative to the experimental use of humans or other mammalian species to investigate osmoregulation mechanisms. In addition to reenforcing the conceptual material covered in lecture, this laboratory exercise trains students in a wide range of laboratory and analytical skills, such as calculating and performing dilutions, pipetting, tissue sampling and homogenizing, preparing standard curves, conducting enzymatic assays, and analyzing and interpreting results. Typical student results are presented and discussed, as are common experimental and conceptual mistakes made by students.

Structures of dense glycine and alanine adlayers on chiral Cu(3,1,17) surfaces.

Density Functional Theory calculations have been used to predict the structures of dense glycine and alanine adlayers on Cu(3,1,17)(S). Facets of this chiral Cu surface result from adsorbate-induced surface reconstruction when glycine or alanine are adsorbed and annealed on Cu(100). We have calculated the surface energy changes associated with this surface reconstruction. Our results allow the enantiospecificity of this reconstruction following adsorption of enantiopure or racemic alanine on Cu(100) to be discussed. The overall stability of glycine and alanine adlayers on Cu(3,1,17)(S) arises from an interplay between the formation of chemical bonds with the Cu surface, deformations in the adsorbed molecules during adsorption, and intermolecular hydrogen bonds within the adlayer; none of these factors individually dominates.