Publications by authors named "R M P Woodward"

438 Publications

Hypercrosslinked Polymers as a Photocatalytic Platform for Visible-Light-Driven CO Photoreduction Using H O.

ChemSusChem 2021 Apr 22;14(7):1720-1727. Epub 2021 Jan 22.

Barrer Centre, Department of Chemical Engineering, South Kensington Campus, Imperial College London, London, SW7 2AZ, UK.

The design of robust, high-performance photocatalysts is key for the success of solar fuel production by CO conversion. In this study, hypercrosslinked polymer (HCP) photocatalysts have been developed for the selective reduction of CO to CO, combining excellent CO sorption capacities, good general stabilities, and low production costs. HCPs are active photocatalysts in the visible light range, significantly outperforming the benchmark material, TiO P25, using only sacrificial H O. It is hypothesized that superior H O adsorption capacities facilitate access to photoactive sites, improving photocatalytic conversion rates when compared to sacrificial H . These polymers are an intriguing set of organic photocatalysts, displaying no long-range order or extended π-conjugation. The as-synthesized networks are the sole photocatalytic component, requiring no added cocatalyst doping or photosensitizer, representing a highly versatile and exciting platform for solar-energy conversion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cssc.202002824DOI Listing
April 2021

A Randomized, Controlled Trial of the Effect of Allopurinol on Left Ventricular Mass Index in Hemodialysis Patients.

Kidney Int Rep 2021 Jan 4;6(1):146-155. Epub 2020 Dec 4.

Division of Molecular & Clinical Medicine, School of Medicine, Ninewells Hospital, University of Dundee, Dundee, UK.

Introduction: Increased left ventricular mass index (LVMI) is associated with mortality in end-stage renal disease. LVMI regression may improve outcomes. Allopurinol has reduced LVMI in randomized controlled trials in chronic kidney disease, diabetes, and ischemic heart disease. This study investigated whether allopurinol would regress LVMI in hemodialysis patients.

Methods: This was a randomized placebo-controlled double-blind multicenter trial funded by the British Heart Foundation (PG/12/72/29743). A total of 80 patients undergoing regular maintenance hemodialysis were recruited from NHS Tayside, NHS Greater Glasgow and Clyde and NHS Ayrshire and Arran in Scotland, UK. Participants were randomly assigned on a 1:1 ratio to 12 months of therapy with allopurinol 300 mg or placebo after each dialysis session. The primary outcome was change in LVMI, as assessed by cardiac magnetic resonance imaging (CMRI) at baseline and 12 months. Secondary outcomes were change in BP, flow-mediated dilation (FMD), augmentation indices (AIx), and pulse wave velocity (PWV).

Results: A total of 53 patients, with a mean age of 58 years, completed the study and had CMRI follow-up data for analysis. Allopurinol did not regress LVMI (change in LVMI: placebo +3.6 ± 10.4 g/m; allopurinol: +1.6 ± 11 g/m;  = 0.49). Allopurinol had no demonstrable effect on BP, FMD, AIx, or PWV.

Conclusion: Compared with placebo, treatment with allopurinol did not regress LVMI in this trial.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ekir.2020.10.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783562PMC
January 2021

Retinopathy in adults with hypertension and diabetes mellitus in Western Tanzania: a cross-sectional study.

Trop Med Int Health 2020 10 3;25(10):1214-1225. Epub 2020 Aug 3.

Department of Ophthalmology, Weill Cornell Medical College, New York, NY, USA.

Objective: Little is known about the retinal manifestations of arterial hypertension (HTN) and diabetes mellitus (DM) in Western Tanzania and how to maximise the utilisation of scarce eye health resources. To address this, we determined the prevalence of hypertensive and diabetic retinopathy (DR), associated risk factors and relevant patient knowledge.

Methods: Adults with HTN or DM attending outpatient clinics at Bugando Medical Center (BMC) from June to August 2017 were enrolled. Fundus photographs were obtained, and data were collected on blood pressure (BP), body mass index (BMI), blood sugar, visual acuity (VA) and responses to questions about the effects of HTN and DM on the eye.

Results: A total of 180 persons were screened. When only individuals with DR were considered, bivariate regression found systolic BP was significantly associated with severity of DR (P = 0.034). Receiver operating characteristic (ROC) curve analysis using the maximum Youden index revealed the optimum cut-off using duration of DM to predict any DR was 8 years (AUC = 0.75, 95% CI 0.65-0.85). Fewer persons with HTN were aware of the effect of high BP on the eye (61.6%) than persons with DM who were aware of the effect of high blood sugar on the eye (74.4%) (P = 0.048).

Conclusion: Efforts should be made to vigorously treat HTN among adults with DM and refer adults with duration of DM of 8 years or more for a dilated retinal examination. Additional efforts should be made to promote awareness of the sight threatening potential of HTN in resource-limited settings.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/tmi.13463DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7785861PMC
October 2020

Effect of Empagliflozin on Left Ventricular Volumes in Patients With Type 2 Diabetes, or Prediabetes, and Heart Failure With Reduced Ejection Fraction (SUGAR-DM-HF).

Circulation 2021 Feb 13;143(6):516-525. Epub 2020 Nov 13.

Institute of Cardiovascular and Medical Sciences, British Heart Foundation Glasgow Cardiovascular Research Centre (M.M.Y.L., K.J.M.B., K.M., G.R., R.T.C., C.B., L.C., K.F.D., N.N.L., C.J.P., J.R.P., P.W., A.R., P.B.M., J.J.V.M., P.S.J., M.C.P., N.S.), University of Glasgow, United Kingdom.

Background: Sodium-glucose cotransporter 2 inhibitors reduce the risk of heart failure hospitalization and cardiovascular death in patients with heart failure and reduced ejection fraction (HFrEF). However, their effects on cardiac structure and function in HFrEF are uncertain.

Methods: We designed a multicenter, randomized, double-blind, placebo-controlled trial (the SUGAR-DM-HF trial [Studies of Empagliflozin and Its Cardiovascular, Renal and Metabolic Effects in Patients With Diabetes Mellitus, or Prediabetes, and Heart Failure]) to investigate the cardiac effects of empagliflozin in patients in New York Heart Association functional class II to IV with a left ventricular (LV) ejection fraction ≤40% and type 2 diabetes or prediabetes. Patients were randomly assigned 1:1 to empagliflozin 10 mg once daily or placebo, stratified by age (<65 and ≥65 years) and glycemic status (diabetes or prediabetes). The coprimary outcomes were change from baseline to 36 weeks in LV end-systolic volume indexed to body surface area and LV global longitudinal strain both measured using cardiovascular magnetic resonance. Secondary efficacy outcomes included other cardiovascular magnetic resonance measures (LV end-diastolic volume index, LV ejection fraction), diuretic intensification, symptoms (Kansas City Cardiomyopathy Questionnaire Total Symptom Score, 6-minute walk distance, B-lines on lung ultrasound, and biomarkers (including N-terminal pro-B-type natriuretic peptide).

Results: From April 2018 to August 2019, 105 patients were randomly assigned: mean age 68.7 (SD, 11.1) years, 77 (73.3%) male, 82 (78.1%) diabetes and 23 (21.9%) prediabetes, mean LV ejection fraction 32.5% (9.8%), and 81 (77.1%) New York Heart Association II and 24 (22.9%) New York Heart Association III. Patients received standard treatment for HFrEF. In comparison with placebo, empagliflozin reduced LV end-systolic volume index by 6.0 (95% CI, -10.8 to -1.2) mL/m (=0.015). There was no difference in LV global longitudinal strain. Empagliflozin reduced LV end-diastolic volume index by 8.2 (95% CI, -13.7 to -2.6) mL/m (=0.0042) and reduced N-terminal pro-B-type natriuretic peptide by 28% (2%-47%), =0.038. There were no between-group differences in other cardiovascular magnetic resonance measures, diuretic intensification, Kansas City Cardiomyopathy Questionnaire Total Symptom Score, 6-minute walk distance, or B-lines.

Conclusions: The sodium-glucose cotransporter 2 inhibitor empagliflozin reduced LV volumes in patients with HFrEF and type 2 diabetes or prediabetes. Favorable reverse LV remodeling may be a mechanism by which sodium-glucose cotransporter 2 inhibitors reduce heart failure hospitalization and mortality in HFrEF. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03485092.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/CIRCULATIONAHA.120.052186DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864599PMC
February 2021

Psoriatic arthritis is associated with adverse body composition predictive of greater coronary heart disease and type 2 diabetes propensity - a cross-sectional study.

Rheumatology (Oxford) 2021 Apr;60(4):1858-1862

Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.

Objectives: To compare body composition in PsA with metabolic disease free (MDF) controls and type 2 diabetes and assess body-composition predicted propensity for cardiometabolic disease.

Methods: Detailed MRI body composition profiles of 26 PsA participants from the IMAPA study were compared with 130 age, sex and BMI-matched MDF controls and 454 individuals with type 2 diabetes from UK Biobank. The body-composition predicted propensity for coronary heart disease (CHD) and type 2 diabetes was compared between PsA and matched MDF controls.

Results: PsA participants had a significantly greater visceral adipose tissue (VAT) volume [mean 5.89 l (s.d. 2.10 l)] compared with matched-MDF controls [mean 4.34 l (s.d. 1.83 l)] (P <0.001) and liver fat percentage [median 8.88% (interquartile range 4.42-13.18%)] compared with MDF controls [3.29% (1.98-7.25%)] (P <0.001). These differences remained significant after adjustment for age, sex and BMI. There were no statistically significant differences in VAT, liver fat or muscle fat infiltration (MFI) between PsA and type 2 diabetes. PsA participants had a lower thigh muscle volume than MDF controls and those with type 2 diabetes. Body composition-predicted propensity for CHD and type 2 diabetes was 1.27 and 1.83 times higher, respectively, for PsA compared with matched-MDF controls.

Conclusion: Individuals with PsA have an adverse body composition phenotype with greater visceral and ectopic liver fat and lower thigh muscle volume than matched MDF controls. Body fat distribution in PsA is more in keeping with the pattern observed in type 2 diabetes and is associated with greater propensity to cardiometabolic disease. These data support the need for greater emphasis on weight loss in PsA management to lessen CHD and type 2 diabetes risk.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/rheumatology/keaa604DOI Listing
April 2021

Feasibility of removable balloon implant for simultaneous magnetic nanoparticle heating and HDR brachytherapy of brain tumor resection cavities.

Int J Hyperthermia 2020 ;37(1):1189-1201

Radiation Oncology Department, Thomas Jefferson University, Philadelphia, PA, USA.

Aim: Hyperthermia (HT) has been shown to improve clinical response to radiation therapy (RT) for cancer. Synergism is dramatically enhanced if HT and RT are combined simultaneously, but appropriate technology to apply treatments together does not exist. This study investigates the feasibility of delivering HT with RT to a 5-10mm annular rim of at-risk tissue around a tumor resection cavity using a temporary thermobrachytherapy (TBT) balloon implant.

Methods: A balloon catheter was designed to deliver radiation from High Dose Rate (HDR) brachytherapy concurrent with HT delivered by filling the balloon with magnetic nanoparticles (MNP) and immersing it in a radiofrequency magnetic field. Temperature distributions in brain around the TBT balloon were simulated with temperature dependent brain blood perfusion using numerical modeling. A magnetic induction system was constructed and used to produce rapid heating (>0.2°C/s) of MNP-filled balloons in brain tissue-equivalent phantoms by absorbing 0.5 W/ml from a 5.7 kA/m field at 133 kHz.

Results: Simulated treatment plans demonstrate the ability to heat at-risk tissue around a brain tumor resection cavity between 40-48°C for 2-5cm diameter balloons. Experimental thermal dosimetry verifies the expected rapid and spherically symmetric heating of brain phantom around the MNP-filled balloon at a magnetic field strength that has proven safe in previous clinical studies.

Conclusions: These preclinical results demonstrate the feasibility of using a TBT balloon to deliver heat simultaneously with HDR brachytherapy to tumor bed around a brain tumor resection cavity, with significantly improved uniformity of heating over previous multi-catheter interstitial approaches. Considered along with results of previous clinical thermobrachytherapy trials, this new capability is expected to improve both survival and quality of life in patients with glioblastoma multiforme.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/02656736.2020.1829103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864554PMC
January 2020

A comparison between MRI and CT in the assessment of primary tumour volume in mesothelioma.

Lung Cancer 2020 12 1;150:12-20. Epub 2020 Oct 1.

Glasgow Pleural Disease Unit, Queen ElIzabeth University Hospital, Glasgow, United Kingdom; Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom. Electronic address:

Introduction: Primary tumour staging in Malignant Pleural Mesothelioma (MPM) using Computed Tomography (CT) imaging is confounded by perception errors reflecting low spatial resolution between tumour and adjacent structures. Augmentation using perfusion CT is constrained by radiation dosage. In this study, we evaluated an alternative tumour staging method using perfusion-tuned Magnetic Resonance Imaging (MRI).

Methods: Consecutive patients with suspected MPM were recruited to a prospective observational study. All had MRI (T1-weighted, isotropic, contrast-enhanced 3-Tesla perfusion imaging) and CT (contrast-enhanced) pre-biopsy. Patients diagnosed with MPM underwent MRI and CT volumetry, with readers blinded to clinical data. MRI volumetry was semi-automated, using signal intensity limits from perfusion studies to grow tumour regions within a pleural volume. A similar CT method was not possible, therefore all visible tumour was manually segmented. MRI and CT volumes were compared (agreement, correlation, analysis time, reproducibility) and associations with survival examined using Cox regression.

Results: 58 patients were recruited and had MRI before biopsy. 31/58 were diagnosed with MPM and these scans were used for volumetry. Mean (SD) MRI and CT volumes were 370 cm and 302 cm, respectively. MRI volumes were larger (average bias 61.9 cm (SD 116), 95 % limits (-165.5 - 289 cm), moderately correlated with CT (r = 0.56, p = 0.002) and independently associated with survival (HR 4.03 (95 % CI 1.5-11.55), p = 0.006). CT volumes were not associated with survival, took longer to compute than MRI volumes (mean (SD) 151 (19) v 14 (2) minutes, p=<0.0001) and were less reproducible (inter-observer ICC 0.72 for CT, 0.96 for MRI).

Conclusions: MRI and CT generate different tumour volumes in MPM. In this study, MRI volumes were larger and were independently associated with survival. MRI volumetry was quicker and more reproducible than CT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.lungcan.2020.09.025DOI Listing
December 2020

A general ink formulation of 2D crystals for wafer-scale inkjet printing.

Sci Adv 2020 Aug 12;6(33):eaba5029. Epub 2020 Aug 12.

Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK.

Recent advances in inkjet printing of two-dimensional (2D) crystals show great promise for next-generation printed electronics development. Printing nonuniformity, however, results in poor reproducibility in device performance and remains a major impediment to their large-scale manufacturing. At the heart of this challenge lies the coffee-ring effect (CRE), ring-shaped nonuniform deposits formed during postdeposition drying. We present an experimental study of the drying mechanism of a binary solvent ink formulation. We show that Marangoni-enhanced spreading in this formulation inhibits contact line pinning and deforms the droplet shape to naturally suppress the capillary flows that give rise to the CRE. This general formulation supports uniform deposition of 2D crystals and their derivatives, enabling scalable and even wafer-scale device fabrication, moving them closer to industrial-level additive manufacturing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.aba5029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423364PMC
August 2020

Vitamin K for kidney transplant organ recipients: investigating vessel stiffness (ViKTORIES): study rationale and protocol of a randomised controlled trial.

Open Heart 2020 07;7(2)

Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.

Background: Renal transplant recipients (RTRs) exhibit increased vascular stiffness and calcification; these parameters are associated with increased cardiovascular risk. Activity of endogenous calcification inhibitors such as matrix gla protein (MGP) is dependent on vitamin K. RTRs commonly have subclinical vitamin K deficiency. The Vitamin K in kidney Transplant Organ Recipients: Investigating vEssel Stiffness (ViKTORIES) study assesses whether vitamin K supplementation reduces vascular stiffness and calcification in a diverse population of RTR.

Methods And Analysis: ViKTORIES (ISRCTN22012044) is a single-centre, phase II, parallel-group, randomised, double-blind, placebo-controlled trial of the effect of vitamin K supplementation in 90 prevalent RTR. Participants are eligible if they have a functioning renal transplant for 1 year. Those on warfarin, with atrial fibrillation, estimated glomerular filtration rate <15 mL/min/1.73 m or contraindications to MRI are excluded. Treatment is with vitamin K (menadiol diphosphate) 5 mg three times per week for 1 year or matching placebo. All participants have primary and secondary endpoint measures at 0 and 12 months. The primary endpoint is ascending aortic distensibility on cardiac MR imaging. Secondary endpoints include vascular calcification (coronary artery calcium score by CT), cardiac structure and function on MR, carotid-femoral pulse wave velocity, serum uncarboxylated MGP, transplant function, proteinuria and quality of life. The study is powered to detect 1.0×10 mm Hg improvement in ascending aortic distensibility in the vitamin K group relative to placebo at 12 months. Analyses will be conducted as between-group differences at 12 months by intention to treat.

Discussion: This trial may identify a novel, inexpensive and low-risk treatment to improve surrogate markers of cardiovascular risk in RTR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/openhrt-2019-001070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368482PMC
July 2020

Microinstability of the hip: a systematic review of the imaging findings.

Skeletal Radiol 2020 Dec 25;49(12):1903-1919. Epub 2020 Jun 25.

University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.

Objectives: To undertake a systematic review of the morphologic features associated with hip microinstability and determine whether there are suggestive or diagnostic imaging findings.

Methods: Four electronic databases were searched up to September 2019 to identify original research reporting morphologic features in individuals with either a clinical diagnosis of hip microinstability (instability without overt subluxation/dislocation) or those with symptomatic laxity demonstrated on imaging (increased femoral head translation/distraction or capsular volume). Studies focussing on individuals with pre-existing hip conditions (including definite dysplasia (lateral centre edge angle < 20°), significant trauma, previous dislocation or surgery were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

Results: Twenty-two studies met inclusion criteria (clinical diagnosis of microinstability n = 15 and demonstration of laxity n = 7). Imaging information gathered from the studies includes radiographs (n = 14), MRI (n = 6), MR arthrography (n = 4), CT (n = 1) and intraoperative examination. Most studies exhibited design features associated with an overall high or unclear risk of bias. Some dysplastic features are associated with microinstability or laxity reference measures; however, microinstability is frequently diagnosed in those with a lateral centre edge angle > 25°. Other associated imaging findings reported include impingement morphology, anterior labral tearing, femoral head chondral injury, ligamentum teres tears and capsular attenuation.

Conclusions: The current literature does not provide strong evidence for imaging features diagnostic of microinstability. In the appropriate clinical context, dysplastic morphology, anterior labral tears and ligamentum teres tears may be suggestive of this condition although further research is needed to confirm this.

Prospero Registration: CRD42019122406.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00256-020-03516-7DOI Listing
December 2020

Savoring Water Chestnuts.

Authors:
Rivers Woodward

Fam Med 2020 05;52(5):369-370

Mountain Area Health Education Center, Asheville, NC.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.22454/FamMed.2020.903918DOI Listing
May 2020

Valuing the Cancer Mortality Risk Reduction from Lowering the Arsenic Maximum Contaminant Level in New Hampshire Municipal Water Supplies.

Environ Manage 2020 06 21;65(6):725-736. Epub 2020 Apr 21.

Department of Economics, University of New Hampshire, Durham, NH, USA.

This study uses a 2018 stated preference survey to elicit a willingness to pay (WTP) to reduce the cancer morbidity and mortality risk from arsenic exposure through drinking water. Respondents who use a public water supply are willing to pay $35.43 per month for the risk reduction associated with lowering the maximum allowable level of arsenic in drinking water from 10 to a hypothetical level of 3 ppb; households on private wells are willing to pay $29.19. Respondents from households with children were willing to pay significantly more than respondents from households without children. We derive values of a statistical life (VSL) of $4.61 million and $3.48 million per household member, respectively, in households using municipal or well water. Shortly after the initial release of these findings, New Hampshire became the second state to set a maximum allowable level for arsenic below the national limit of 10 ppb.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00267-020-01288-3DOI Listing
June 2020

The design of hypercrosslinked polymers from benzyl ether self-condensing compounds and external crosslinkers.

Chem Commun (Camb) 2020 May;56(36):4938-4941

Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK.

Hypercrosslinked polymers were produced via the self-condensation of benzyl ether compounds, providing a one-component route to highly porous networks and significant reductions in catalyst waste compared to conventional routes. These compounds also represent a new class of external crosslinkers, able to impart improved textural properties when compared to standard aliphatic crosslinkers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0cc01002bDOI Listing
May 2020

Understanding longitudinal biventricular structural and functional changes in a pulmonary hypertension Sugen-hypoxia rat model by cardiac magnetic resonance imaging.

Pulm Circ 2020 Jan-Mar;10(1):2045894019897513. Epub 2020 Feb 10.

Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK.

Cardiac magnetic resonance-derived ventricular variables are predictive of mortality in pulmonary arterial hypertension. Rodent models which emphasize ventricular function, allowing serial monitoring, are needed to identify pathophysiological features and novel therapies for pulmonary arterial hypertension. We investigated longitudinal changes in the Sugen-hypoxia model during disease progression. Sprague Dawley rats ( = 32) were divided into two groups. (1) Sugen-hypoxia: a dose of subcutaneous Sugen-5416 and placed in hypobaric hypoxia for two weeks followed by normoxia for three weeks. (2) Normoxia: maintained at normal pressure for five weeks. Rats were examined at five or eight weeks with right-heart catheter, cardiac magnetic resonance, and autopsy. Compared to normoxic controls (23.9 ± 4.1 mmHg), right ventricular systolic pressure was elevated in Sugen-hypoxia rats at five and eight weeks (40.9 ± 15.5 mmHg,  = 0.026; 48.9 ± 9.6 mmHg,  = 0.002). Right ventricular end-systolic volume index was increased in eight weeks Sugen-hypoxia (0.28 ± 0.04 µlcm,  = 0.003) compared to normoxic controls (0.18 ±0.03 mlcm). There was progressive dilatation of the right ventricular at eight weeks Sugen-hypoxia compared to normoxic controls (0.75 ± 0.13 µlcm vs 0.56 ± 0.1 µlcm = 0.02). Ventricle mass index by cardiac magnetic resonance at five weeks (0.34 ± 0.06,  = 0.003) and eight weeks Sugen-hypoxia (0.34 ± 0.06,  = 0.002) were higher than normoxic controls (0.21 ± 0.04). Stroke volume, right ventricular ejection fraction, and left ventricular variables were preserved in Sugen-hypoxia. Ventricular changes during the course of illness in a pulmonary arterial hypertension rodent model can be examined by cardiac magnetic resonance. These changes including right ventricular hypertrophy and subsequent dilatation are similar to those seen in pulmonary arterial hypertension patients. Despite the persisting pulmonary hypertension, there are features of adaptive cardiac remodeling through the study duration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/2045894019897513DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011361PMC
February 2020

Performance of Donor-derived Cell-free DNA Assays in Kidney Transplant Patients.

Transplantation 2020 05;104(5):e135

Research & Development, CareDx, Inc., Brisbane, CA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/TP.0000000000003084DOI Listing
May 2020

X-ray crystallographic structure of BshB, the zinc-dependent deacetylase involved in bacillithiol biosynthesis.

Protein Sci 2020 04 31;29(4):1035-1039. Epub 2019 Dec 31.

Department of Chemistry, Grand Valley State University, Allendale, Michigan.

Many gram-positive bacteria produce bacillithiol to aid in the maintenance of redox homeostasis and degradation of toxic compounds, including the antibiotic fosfomycin. Bacillithiol is produced via a three-enzyme pathway that includes the action of the zinc-dependent deacetylase BshB. Previous studies identified conserved aspartate and histidine residues within the active site that are involved in metal binding and catalysis, but the enzymatic mechanism is not fully understood. Here we report two X-ray crystallographic structures of BshB from Bacillus subtilis that provide insight into the BshB catalytic mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pro.3808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7096702PMC
April 2020

Comparing the interobserver reproducibility of different regions of interest on multi-parametric renal magnetic resonance imaging in healthy volunteers, patients with heart failure and renal transplant recipients.

MAGMA 2020 Feb 10;33(1):103-112. Epub 2019 Dec 10.

Room 311, Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, 126 University Place, Glasgow, G12 8TA, UK.

Objective: To assess interobserver reproducibility of different regions of interest (ROIs) on multi-parametric renal MRI using commercially available software.

Materials And Methods: Healthy volunteers (HV), patients with heart failure (HF) and renal transplant recipients (Tx) were recruited. Localiser scans, T1 mapping and pseudo-continuous arterial spin labelling (pCASL) were performed. HV and Tx also underwent diffusion-weighted imaging to allow calculation of apparent diffusion coefficient (ADC). For T1, pCASL and ADC, ROIs were drawn for whole kidney (WK), cortex (Cx), user-defined representative cortex (rep-Cx) and medulla. Intraclass correlation coefficient (ICC) and coefficient of variation (CoV) were assessed.

Results: Forty participants were included (10 HV, 10 HF and 20 Tx). The ICC for renal volume was 0.97 and CoV 6.5%. For T1 and ADC, WK, Cx, and rep-Cx were highly reproducible with ICC ≥ 0.76 and CoV < 5%. However, cortical pCASL results were more variable (ICC > 0.86, but CoV up to 14.2%). While reproducible, WK values were derived from a wide spread of data (ROI standard deviation 17% to 55% of the mean value for ADC and pCASL, respectively). Renal volume differed between groups (p < 0.001), while mean cortical T1 values were greater in Tx compared to HV (p = 0.009) and HF (p = 0.02). Medullary T1 values were also higher in Tx than HV (p = 0.03), while medullary pCASL values were significantly lower in Tx compared to HV and HF (p = 0.03 for both).

Discussion: Kidney volume calculated by manually contouring a localiser scan was highly reproducible between observers and detected significant differences across patient groups. For T1, pCASL and ADC, Cx and rep-Cx ROIs are generally reproducible with advantages over WK values.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10334-019-00809-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7021749PMC
February 2020

Graphene-aramid nanocomposite fibres via superacid co-processing.

Chem Commun (Camb) 2019 Sep;55(78):11703-11706

Manchester Institute of Biotechnology, The University of Manchester, M1 7DN, UK.

The development of graphene-polymer nanocomposite materials has been hindered by issues such as poor colloidal stability of graphene in liquid media, weak interactions between graphene and the host polymers as well as the lack of scalable and economical graphene synthesis routes. Chlorosulfonic acid (CSA) can spontaneously disperse graphene without the need for mechanical agitation, chemical functionalisation or surfactant stabilisation,1 however is incompatible with most polymers and organic materials. Here, we demonstrate how poly(p-phenylene terephthalamide) (PPTA) - the polymer which constitutes Kevlar - can be co-processed with graphene in CSA and wet-spun into nanocomposite fibres with minimal aggregation of graphene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cc04548aDOI Listing
September 2019

In vitro tissue culture model validation-the influence of tissue culture components on IPL energy output.

Lasers Med Sci 2019 Oct 25;34(8):1575-1582. Epub 2019 Jul 25.

Swansea University Medical School, Grove Building, Swansea, SA2 8PP, UK.

Intense pulsed light (IPL) has been used therapeutically in a number of clinical settings and has been shown to have a photobiomodulatory effect on connective tissue cells, such as those derived from skin and tendon. In vitro cell culture models are essential tools preclinically in investigating such treatment modalities, as they help in optimising parameters for successful treatment. However, as culture system components have been reported to absorb part of the irradiated energy, which in turn has a bearing on the amount of light reaching the cells, it is important to establish specific parameters for the particular in vitro model used. This study, therefore, investigates the effect of our tissue culture system components on the IPL energy delivered. Individual wells of multi-well plates were irradiated with IPL at different device settings and under variable culture conditions (e.g. in the absence or presence of cell culture media with or without the pH indicator dye, phenol red), and the energy lost through the culture system determined. Our data demonstrated that the IPL device delivered significantly lower outputs than those published, and energy absorption by the culture equipment would further reduce fluencies delivered to the cell monolayer. Furthermore, energy absorption by media containing phenol red was marginally greater than clear media and resulted in only a small increase in temperature, which would not be harmful to cells. The use of phenol red-containing media therefore is valid and physiologically relevant when examining light-culture system interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10103-019-02747-yDOI Listing
October 2019

Gene expression profiling and racial disparities in outcomes after heart transplantation.

J Heart Lung Transplant 2019 08 24;38(8):820-829. Epub 2019 May 24.

Section of Heart Failure, Cardiac Transplant, and Mechanical Circulatory Support, and Department of Medicine, Stanford University, Stanford, California. Electronic address:

Background: African Americans (AAs) have lower survival rates after heart transplantation (HTx) than Caucasians. The aim of this analysis was to evaluate racial differences in gene expression and their associations with survival and the composite outcome of death, retransplant, rejection with hemodynamic compromise, and graft dysfunction in the Outcomes AlloMap Registry.

Methods: Registry participants included low-risk Caucasian and AA heart transplant recipients with a baseline and at least 1 follow-up gene expression test (AlloMap(C)) within the first year after HTx. The Kaplan-Meier method with delayed entry was used to describe differences in outcomes. Multivariable Cox hazard regression was used to evaluate the associations of overall gene expression profiling score, MARCH8 and FLT3 expression, and tacrolimus levels with each outcome, and stratified Cox models were developed to quantify race-specific associations.

Results: Among 933 eligible recipients, 737 (79%) were Caucasian and 196 (21%) were AA. Compared with Caucasians, AAs were significantly younger (55 vs 59 years, p < 0.001), with higher rates of non-ischemic cardiomyopathy (68% vs 50%, p < 0.001), sensitization (>10% panel reactive antibody, 16% vs 9.1%, p = 0.009), and human leukocyte antigen mismatches (7 vs 7, p = 0.01), but less frequent primary cytomegalovirus serostatus mismatch (14.31% vs 27.3%, p < 0.001). Overall, AAs had an increased adjusted mortality risk (hazard ratio [HR] 4.13, p = 0.007). Higher tacrolimus levels were associated with decreased mortality in AAs (HR 0.62, p = 0.009). Overall gene expression profiling score was associated with increased mortality among Caucasians (HR 1.21, p = 0.048). In Caucasians, but not AAs, overexpression of MARCH8 was associated with increased mortality (HR 2.90, p = 0.001). FLT3 upregulation was associated with increased mortality (HR 2.42, p = 0.033) in AAs. There was an inverse relationship between FLT3 expression and tacrolimus levels (-0.029 and -0.176, respectively) in Caucasians and AAs.

Conclusions: AAs have a significantly higher mortality risk after HTx than Caucasians, even in the low-risk Outcomes AlloMap Registry population. AAs and Caucasians had differential outcomes based upon the varying expression of MARCH8 and FLT3 genes following HTx.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.healun.2019.05.008DOI Listing
August 2019

Q-switched Dy:ZBLAN fiber lasers beyond 3 μm: comparison of pulse generation using acousto-optic modulation and inkjet-printed black phosphorus.

Opt Express 2019 May;27(10):15032-15045

We report high-energy mid-infrared pulse generation by Q-switching of dysprosium-doped fiber lasers for the first time. Two different modulation techniques are demonstrated. Firstly, using active acousto-optic modulation, pulses are produced with up to 12 μJ energy and durations as short as 270 ns, with variable repetition rates from 100 Hz to 20 kHz and central wavelengths tunable from 2.97 to 3.23 μm. Experiments are supported by numerical modeling, identifying routes for improved pulse energies and to avoid multi-pulsing by careful choice of modulator parameters. Secondly, we demonstrate passive Q-switching by fabricating an inkjet-printed black phosphorus saturable absorber, simplifying the cavity and generating 1.0 μJ pulses with 740 ns duration. The performance and relative merits of each modulation approach are then critically discussed. These demonstrations highlight the potential of dysprosium as a versatile gain medium for high-performance pulsed sources beyond 3 μm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.27.015032DOI Listing
May 2019

Segmenting Mechanomyography Measures of Muscle Activity Phases Using Inertial Data.

Sci Rep 2019 04 3;9(1):5569. Epub 2019 Apr 3.

Imperial College London, Department of Mechanical Engineering, London, UK.

Electromyography (EMG) is the standard technology for monitoring muscle activity in laboratory environments, either using surface electrodes or fine wire electrodes inserted into the muscle. Due to limitations such as cost, complexity, and technical factors, including skin impedance with surface EMG and the invasive nature of fine wire electrodes, EMG is impractical for use outside of a laboratory environment. Mechanomyography (MMG) is an alternative to EMG, which shows promise in pervasive applications. The present study used an exerting squat-based task to induce muscle fatigue. MMG and EMG amplitude and frequency were compared before, during, and after the squatting task. Combining MMG with inertial measurement unit (IMU) data enabled segmentation of muscle activity at specific points: entering, holding, and exiting the squat. Results show MMG measures of muscle activity were similar to EMG in timing, duration, and magnitude during the fatigue task. The size, cost, unobtrusive nature, and usability of the MMG/IMU technology used, paired with the similar results compared to EMG, suggest that such a system could be suitable in uncontrolled natural environments such as within the home.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-41860-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447582PMC
April 2019

Ultrafast mid-infrared fiber laser mode-locked using frequency-shifted feedback.

Opt Lett 2019 Apr;44(7):1698-1701

We demonstrate ultrashort pulse generation from a fluoride fiber laser co-doped with holmium and praseodymium. To date, the majority of work focused on short pulse generation from this class of fiber laser has employed loss modulators in the cavity, both real and artificial. In this Letter, we alternatively employ a frequency shifting element: an acousto-optic modulator (AOM) in the cavity. This results in mode-locked output of sub-5 ps pulses with 10 nJ of energy at a center wavelength of 2.86 μm and a pulse repetition frequency of 30.1 MHz, equating to a peak power of 1.9 kW. Additional experimental investigation of the relationship between frequency shift and cavity round trip offer insight into the complex underlying dynamics. As a complementary mode-locking technique to conventional loss modulation, this method of pulse-formation may greatly expand the design flexibility of pulsed mid-infrared fiber lasers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OL.44.001698DOI Listing
April 2019

Noninvasive detection of graft injury after heart transplant using donor-derived cell-free DNA: A prospective multicenter study.

Am J Transplant 2019 10 8;19(10):2889-2899. Epub 2019 Apr 8.

Cedars-Sinai Smidt Heart Institute, Los Angeles, California.

Standardized donor-derived cell-free DNA (dd-cfDNA) testing has been introduced into clinical use to monitor kidney transplant recipients for rejection. This report describes the performance of this dd-cfDNA assay to detect allograft rejection in samples from heart transplant (HT) recipients undergoing surveillance monitoring across the United States. Venous blood was longitudinally sampled from 740 HT recipients from 26 centers and in a single-center cohort of 33 patients at high risk for antibody-mediated rejection (AMR). Plasma dd-cfDNA was quantified by using targeted amplification and sequencing of a single nucleotide polymorphism panel. The dd-cfDNA levels were correlated to paired events of biopsy-based diagnosis of rejection. The median dd-cfDNA was 0.07% in reference HT recipients (2164 samples) and 0.17% in samples classified as acute rejection (35 samples; P = .005). At a 0.2% threshold, dd-cfDNA had a 44% sensitivity to detect rejection and a 97% negative predictive value. In the cohort at risk for AMR (11 samples), dd-cfDNA levels were elevated 3-fold in AMR compared with patients without AMR (99 samples, P = .004). The standardized dd-cfDNA test identified acute rejection in samples from a broad population of HT recipients. The reported test performance characteristics will guide the next stage of clinical utility studies of the dd-cfDNA assay.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ajt.15339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6790566PMC
October 2019

Feature-tracking myocardial strain in healthy adults- a magnetic resonance study at 3.0 tesla.

Sci Rep 2019 03 1;9(1):3239. Epub 2019 Mar 1.

British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, UK.

We analyzed feature-tracking derived circumferential and longitudinal strain in healthy volunteers who underwent cardiac magnetic resonance imaging (CMR) at 3.0 T. 88 healthy adults (44.6 ± 18.0 years old, 49% male), without prior cardiovascular disease, underwent CMR at 3.0 T including cine, and late gadolinium enhancement in subjects >45 years. LV functional analysis and feature-tracking strain analyses were carried out. Global strain had better reproducibility than segmental strain. There was a sex specific difference global longitudinal strain (mean ± SD, -18.48 ± 3.65% (male), -21.91 ± 3.01% (female), p < 0.001), but not global circumferential strain (mean ± SD, -25.41 ± 4.50% (male), -27.94 ± 3.48% (female), p = 0.643). There was no association of strain with ageing after accounting for sex for both global longitudinal and circumferential strain. Feature-tracking strain analysis is feasible at 3.0 T. Healthy female volunteers demonstrated higher magnitudes of global longitudinal strain when compared to male counterparts. Whilst global cine-strain has good reproducibility, segmental strain does not.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-39807-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6397185PMC
March 2019

Adapting myoelectric control in real-time using a virtual environment.

J Neuroeng Rehabil 2019 01 16;16(1):11. Epub 2019 Jan 16.

Center for Bionic Medicine, Shirley Ryan Ability Lab, Chicago, IL, 60611, USA.

Background: Pattern recognition technology allows for more intuitive control of myoelectric prostheses. However, the need to collect electromyographic data to initially train the pattern recognition system, and to re-train it during prosthesis use, adds complexity that can make using such a system difficult. Although experienced clinicians may be able to guide users to ensure successful data collection methods, they may not always be available when a user needs to (re)train their device.

Methods: Here we present an engaging and interactive virtual reality environment for optimal training of a myoelectric controller. Using this tool, we evaluated the importance of training a classifier actively (i.e., moving the residual limb during data collection) compared to passively (i.e., maintaining the limb in a single, neutral orientation), and whether computational adaptation through serious gaming can improve performance.

Results: We found that actively trained classifiers performed significantly better than passively trained classifiers for non-amputees (P < 0.05). Furthermore, collecting data passively with minimal instruction, paired with computational adaptation in a virtual environment, significantly improved real-time performance of myoelectric controllers.

Conclusion: These results further support previous work which suggested active movements during data collection can improve pattern recognition systems. Furthermore, adaptation within a virtual guided serious game environment can improve real-time performance of myoelectric controllers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12984-019-0480-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6335715PMC
January 2019

Optimized laser-written ZBLAN fiber Bragg gratings with high reflectivity and low loss.

Opt Lett 2019 Jan;44(2):423-426

We report the direct femtosecond laser inscription of type-I fiber Bragg gratings (FBGs) into the core of soft-glass ZBLAN fibers. We investigate and compare various fabrication methods such as single pass (line by line), double pass, and stacking (plane by plane) to create the highest reflectivity FBGs (99.98%) for mid-infrared (mid-IR) applications. In addition, we experimentally demonstrate how the parameters that influence the coupling coefficient, i.e., refractive index modulation and overlap factor, can be controlled in these gratings to specifically tailor the FBG properties. The performance of the direct-written type-I gratings after 6 h of annealing is further analyzed, and the reflectivity increases by approximately 10 dB. To the best of our knowledge, this is the first demonstration of temperature-stable mid-IR FBGs with highest coupling coefficient (464  m) and lowest loss (<0.5  dB/cm) without the use of an expensive phase mask.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OL.44.000423DOI Listing
January 2019

Robust Pattern Recognition Myoelectric Training for Improved Online Control within a 3D Virtual Environment.

Annu Int Conf IEEE Eng Med Biol Soc 2018 Jul;2018:4701-4704

It has been shown that maintaining a neutral arm position during collection of pattern recognition training data for myoelectric prosthesis control results in high offline classification accuracies; however, that precision does not translate to real-time applications, when the arm is used in different positions. Previous studies have shown that collecting training data with the arm in a variety of positions can improve pattern recognition control systems. In this work, we extended these findings to real-time myoelectric control in an immersive testing environment using virtual reality. We show that collecting training data for a pattern recognition algorithm under dynamic conditions, where the user moves their arm, significantly improves control efficiency and achievement of testing metrics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/EMBC.2018.8513183DOI Listing
July 2018

Comparing the Effects of Signal Noise on Pattern Recognition and Linear Regression-Based Myoelectric Controllers.

Annu Int Conf IEEE Eng Med Biol Soc 2018 Jul;2018:2132-2135

Myoelectric pattern recognition using linear discriminant analysis (LDA) classifiers has been a wellestablished control method for upper limb prostheses for many years. More recently, linear regression (LR) controllers have been proposed as an alternative solution due to their ability to control multiple degrees of freedom (DOF) simultaneously. The aim of this experiment was to compare the online performance of LDA and LR control systems under three electromyographic (EMG) signal conditions: baseline, noise in all channels, and noise in a single channel. To simulate the last two conditions, different levels of Gaussian noise were added to the EMG signals. Completion rate, path efficiency, dwelling time, and completion time were computed after virtual Fitts' Law tasks. While both controllers were significantly affected by the lowest noise levels, we found no significant differences between the controllers under the baseline and all-channel noise conditions. However, the LDA controller outperformed the LR controller in the single-channel noise condition. Therefore, while both controllers are comparable in most cases, the added complexity of simultaneous control affects an LR controller's performance under certain noise conditions. Based on these results, neither control system should be dismissed in future developments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/EMBC.2018.8512693DOI Listing
July 2018

A coupled recreational anglers' decision and fish population dynamics model.

PLoS One 2018 31;13(10):e0206537. Epub 2018 Oct 31.

Department of Agricultural Economics, Texas A&M University, College Station, TX, United States of America.

The effective management of fish populations requires understanding of both the biology of the species being managed and the behavior of the humans who harvest those species. For many marine fisheries, recreational harvests represent a significant portion of the total fishing mortality. For such fisheries, therefore, a model that captures the dynamics of angler choices and the fish population would be a valuable tool for fisheries management. In this study, we provide such a model, focusing on red drum and spotted seatrout, which are the two of the main recreational fishing targets in the Gulf of Mexico. The biological models are in the form of vector autoregressive models. The anglers' decision model takes the discrete choice approach, in which anglers first decide whether to go fishing and then determine the location to fish based on the distance and expected catch of two species of fish if they decide to go fishing. The coupled model predicts that, under the level of fluctuation in the abundance of the two species experienced in the past 35 years, the number of trips that might be taken by anglers fluctuates moderately. This fluctuation is magnified as the cost of travel decreases because the anglers can travel long distance to seek better fishing conditions. On the other hand, as the cost of travel increases, their preference to fish in nearby areas increases regardless of the expected catch in other locations and variation in the trips taken declines. The model demonstrates the importance of incorporating anglers' decision processes in understanding the changes in a fishing effort level. Although the model in this study still has a room for further improvement, it can be used for more effective management of fish and potentially other populations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0206537PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6209354PMC
April 2019