Electrochemical decarboxylation of carboxylic acids over platinum surfaces for bio-oil upgrading

To mitigate global warming and reduce its impact on our climate, alternative, clean and renewable energy sources must be harnessed to replace fossil fuels. As fluctuations in availability of sun and wind causes technological limitations for solar and wind energy, energy from biomass is explored as well. Biomass can be converted into bio-oil via fast pyrolysis. Raw bio-oil typically contains a wide variety of organic compounds, including carboxylic acids which results in a high corrosivity and low thermal stability. Upgrading processes are required to increase the quality of bio oil. As traditional upgrading technologies operate at high temperatures and pressures, electrochemical techniques are an appealing alternative. Electrochemical decarboxylation of carboxylic acids (also referred to as Kolbe electrolysis) has been proposed to produce valuable compounds while upgrading bio-oil.This dissertation investigates and discusses the electrochemical decarboxylation of short-chain carboxylic acids on platinum anodes under various reaction conditions. The primary aim was to understand the chemical transformations occurring on Pt electrodes, depending on the electrolyte pH, the nature of the carboxylic acid, and morphology of the Pt electrode. In addition, the feasibility of using low loading Pt electrodes to reduce electrode material costs has been discussed and pulsed electrolysis of mixtures of carboxylic acids were used to improve product yield and alter product selectivity. Overall, the aim was to increase the economic viability of electrochemical decarboxylation for bio-oil upgrading.<br/

Is syncope a risk predictor in the general population?

Syncope in the general population is a frequent event often leading to hospitalization, but it is unclear whether syncope in the general population is an independent risk marker for adverse prognosis. In this review, we investigate the current literature and evaluate the prognosis and impact of syncope on adverse outcomes including death and recurrences across different populations with focus on the general population. In wide terms, a syncopal event is related to a higher risk of subsequent falls and injury and cardiac syncope is particularly associated with increased mortality as compared to non-cardiac syncope. The overall prognosis in the general population is by large determined by the underlying presence and severity of a given cardiac disease, but a given underlying cardiac disease can very well be unknown at the time of first syncope so that syncope is the presenting symptom resulting in an independent risk increase. Moreover, syncope is a significant risk predictor of a recurrence across populations. It is im­portant to recognize several risk factors associated with adverse outcome in order to safely navigate in a population where most patients with syncope are healthy and low-risk but where a small number of patients have life-threatening conditions. Further research in the general population should attempt to categorize which patients with syncope need immediate referral and diagnostic testing, and whether this affects the outcome

Eligibility for subcutaneous implantable cardioverter-defibrillators in the adult congenital heart disease population

Background Patients with adult congenital heart disease (ACHD) have an increased risk of arrhythmic, sudden cardiac death. The subcutaneous implantable cardioverter defibrillator (S‐ICD) provides a potentially safer alternative to transvenous ICDs in ACHD. Suitability for S‐ICD depends on the surface ECG which is often abnormal in ACHD patients. This study investigates the proportion of ACHD patients who meet the screening criteria for S‐ICD Methods A standard screening ECG was performed in 102 patients with complex ACHD (Tetralogy of Fallot, Fontan Circulation, Transposition of the Great Arteries). This process was repeated post‐exercise for patients who also had an exercise test. Results Three quarters (75.4%) of ACHD patients meet screening criteria for an S‐ICD with at least 1 suitable vector. The most common number of acceptable vectors in the eligible group was 2 (35% of total population). In only 12% were all three vectors suitable whilst 28% had only 1. The primary vector (equivalent of ECG lead III) was the most common suitable vector, found in 62% of participants who had appropriate sensing vectors. 25 (24.5%) patients failed to meet the S‐ICD screening criteria. Of these, 14 had repaired tetralogy of Fallot. 92% of patients with a Fontan circulation met ECG screening criteria. Of those who had the protocol repeated following their cardiopulmonary exercise test (n = 14), only 1 additional patient failed eligibility criteria. Conclusions A quarter of ACHD patients do not meet eligibility criteria for the S‐ICD. However, more than 90% of patients with a Fontan circulation are suitable for an S‐ICD

Investigating the platinum electrode surface during Kolbe electrolysis of acetic acid

Platinum is commonly applied as the anode material for Kolbe electrolysis of carboxylic acids thanks to its superior performance. Literature claims that the formation of a barrier layer on the Pt anode in carboxylic acid electrolyte suppresses the competing oxygen evolution and promotes anodic decarboxylation. In this work, we show by using a combination of complementary in situ and ex situ surface sensitive techniques, that the presence of acetate ions also prevents the formation of a passive oxide layer on the platinum surface at high anodic potentials even in aqueous electrolyte. Furthermore, Pt dissolves actively under these conditions, challenging the technical implementation of Kolbe electrolysis. Future studies exploring the activity-structure-stability relation of Pt are required to increase the economic viability of Kolbe electrolysis

Detecting Genetic Mosaicism in Cultures of Human Pluripotent Stem Cells.

Genetic changes in human pluripotent stem cells (hPSCs) gained during culture can confound experimental results and potentially jeopardize the outcome of clinical therapies. Particularly common changes in hPSCs are trisomies of chromosomes 1, 12, 17, and 20. Thus, hPSCs should be regularly screened for such aberrations. Although a number of methods are used to assess hPSC genotypes, there has been no systematic evaluation of the sensitivity of the commonly used techniques in detecting low-level mosaicism in hPSC cultures. We have performed mixing experiments to mimic the naturally occurring mosaicism and have assessed the sensitivity of chromosome banding, qPCR, fluorescence in situ hybridization, and digital droplet PCR in detecting variants. Our analysis highlights the limits of mosaicism detection by the commonly employed methods, a pivotal requirement for interpreting the genetic status of hPSCs and for setting standards for safe applications of hPSCs in regenerative medicine

The learning curve associated with the introduction of the subcutaneous implantable defibrillator

Aims: The subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced to overcome complications related to transvenous leads. Adoption of the S-ICD requires implanters to learn a new implantation technique. The aim of this study was to assess the learning curve for S-ICD implanters with respect to implant-related complications, procedure time, and inappropriate shocks (IASs). Methods and results: In a pooled cohort from two clinical S-ICD databases, the IDE Trial and the EFFORTLESS Registry, complications, IASs at 180 days follow-up and implant procedure duration were assessed. Patients were grouped in quartiles based on experience of the implanter and Kaplan-Meier estimates of complication and IAS rates were calculated. A total of 882 patients implanted in 61 centres by 107 implanters with a median of 4 implants (IQR 1,8) were analysed. There were a total of 59 patients with complications and 48 patients with IAS. The complication rate decreased significantly from 9.8% in Quartile 1 (least experience) to 5.4% in Quartile 4 (most experience) (P = 0.02) and non-significantly for IAS from 7.9 to 4.8% (P = 0.10). Multivariable analysis demonstrated a hazard ratio of 0.78 (P = 0.045) for complications and 1.01 (P = 0.958) for IAS. Dual-zone programming increased with experience of the individual implanter (P 13 implants). Conclusion: There is a short and significant learning curve associated with physicians adopting the S-ICD. Performance stab

Are Compression Stockings an Effective Treatment for Orthostatic Presyncope?

Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance

Adjuvant dendritic cell vaccination induces tumor-specific immune responses in the majority of stage III melanoma patients.

Purpose To determine the effectiveness of adjuvant dendritic cell (DC) vaccination to induce tumor-specific immunological responses in stage III melanoma patients.Experimental design Retrospective analysis of stage III melanoma patients, vaccinated with autologous monocyte-derived DC loaded with tumor-associated antigens (TAA) gp100 and tyrosinase after radical lymph node dissection. Skin-test infiltrating lymphocytes (SKILs) obtained from delayed-type hypersensitivity skin-test biopsies were analyzed for the presence of TAA-specific CD8(+) T cells by tetrameric MHC-peptide complexes and by functional TAA-specific T cell assays, defined by peptide-recognition (T2 cells) and/or tumor-recognition (BLM and/or MEL624) with specific production of Th1 cytokines and no Th2 cytokines.Results Ninety-seven patients were analyzed: 21 with stage IIIA, 34 with stage IIIB, and 42 had stage IIIC disease. Tetramer-positive CD8(+) T cells were present in 68 patients (70%), and 24 of them showed a response against all 3 epitopes tested (gp100:154-162, gp100:280-288, and tyrosinase:369-377) at any point during vaccinations. A functional T cell response was found in 62 patients (64%). Rates of peptide-recognition of gp100:154-162, gp100:280-288, and tyrosinase:369-377 were 40%, 29%, and 45%, respectively. Median recurrence-free survival and distant metastasis-free survival of the whole study population were 23.0 mo and 36.8 mo, respectively.Conclusions DC vaccination induces a functional TAA-specific T cell response in the majority of stage III melanoma patients, indicating it is more effective in stage III than in stage IV melanoma patients. Furthermore, performing multiple cycles of vaccinations enhances the chance of a broader immune response