Sustainable degradation of carbon tetrafluoride to non-corrosive useful products by incorporating reduced electron mediator within electro-scrubbing

The degradation of CF4 gas using existing technologies produces other types of greenhouse gas (CO2) and corrosive side products. The main aim of this study is to degrade CF4 gas at room temperature into useful products without producing corrosive side products by mediated electrochemical reduction (MER) process using an electrogenerated Cu1+[Ni2+(CN)4]1− mediator. Initial studies on the electrolytic reduction of the hetero-bimetallic complex in catholyte solution at anodized Ti cathode was monitored by oxidation/reduction potential (ORP) variation whether the Cu2+ or Ni2+ was reduced in the Cu2+[Ni2+(CN)4] and confirmed by electron spin resonance (ESR) spectroscopy the Cu1+[Ni2+(CN)4]1− formation. The concentration variation of Cu1+[Ni2+(CN)4]1− during CF4 injection demonstrated the degradation of CF4 followed the MER by electrogenerated Cu1+[Ni2+(CN)4]1−. Maximum removal efficiency of CF4 using electroscrubbing process was 96% at room temperature. Through the variation in gas phase parameters, the gas phase mass transfer coefficient was calculated that can facilitate scale up the developed process. Fourier transform infrared spectroscopy analysis in both the gas and solution phases showed that CH3CH2OH was the main product that formed during the removal of CF4 by electrogenerated Cu1+[Ni2+(CN)4]1− at electroscrubber along with a small amount of CF3CH3 intermediate. Importantly, this mechanism also avoided formation of the corrosive product HF

Electrochemically generated bimetallic reductive mediator Cu1+ [Ni2+ (CN) 4] 1− for the degradation of CF4 to ethanol by electro-scrubbing

Remediation of electronic gas CF4 using commercially available technologies results in another kind of greenhouse gas and corrosive side products. This investigation aimed to develop CF4 removal at room temperature with formation of useful product by attempting an electrogenerated Cu1+[Ni2+(CN)4]1− mediator. The initial electrolysis of the bimetallic complex at the anodized Ti cathode demonstrated Cu1+[Ni2+(CN)4]1− formation, which was confirmed by additional electron spin resonance results. The degradation of CF4 followed mediated electrochemical reduction by electrogenerated Cu1+[Ni2+(CN)4]1−. The removal efficiency of CF4 of 95% was achieved by this electroscrubbing process at room temperature. The spectral results of online and offline Fourier transform infrared analyzer, either in gas or in solution phase, demonstrated that the product formed during the removal of CF4 by electrogenerated Cu1+[Ni2+(CN)4]1− by electroscrubbing was ethanol (CH3CH2OH), with a small amount of trifluoroethane (CF3CH3) intermediate

Cassava haplotype map highlights fixation of deleterious mutations during clonal propagation

Article purchased; Published online: 17 April 2017Cassava (Manihot esculenta Crantz) is an important staple food crop in Africa and South America; however, ubiquitous deleterious mutations may severely decrease its fitness. To evaluate these deleterious mutations, we constructed a cassava haplotype map through deep sequencing 241 diverse accessions and identified >28 million segregating variants. We found that (i) although domestication has modified starch and ketone metabolism pathways to allow for human consumption, the concomitant bottleneck and clonal propagation have resulted in a large proportion of fixed deleterious amino acid changes, increased the number of deleterious alleles by 26%, and shifted the mutational burden toward common variants; (ii) deleterious mutations have been ineffectively purged, owing to limited recombination in the cassava genome; (iii) recent breeding efforts have maintained yield by masking the most damaging recessive mutations in the heterozygous state but have been unable to purge the mutation burden; such purging should be a key target in future cassava breeding

Genome-wide association and prediction reveals genetic architecture of cassava mosaic disease resistance and prospects for rapid genetic improvement

Published: 13 May 2016Cassava (Manihot esculenta Crantz) is a crucial, under-researched crop feeding millions worldwide, especially in Africa. Cassava mosaic disease (CMD) has plagued production in Africa for over a century. Biparental mapping studies suggest primarily a single major gene mediates resistance. To investigate this genetic architecture, we conducted the first genome-wide association mapping study in cassava with up to 6128 genotyping-by-sequenced African breeding lines and 42,113 reference genome-mapped single-nucleotide polymorphism (SNP) markers. We found a single region on chromosome 8 that accounts for 30 to 66% of genetic resistance in the African cassava germplasm. Thirteen additional regions with small effects were also identified. Further dissection of the major quantitative trait locus (QTL) on chromosome 8 revealed the presence of two possibly epistatic loci and/or multiple resistance alleles, which may account for the difference between moderate and strong disease resistances in the germplasm. Search of potential candidate genes in the major QTL region identified two peroxidases and one thioredoxin. Finally, we found genomic prediction accuracy of 0.53 to 0.58 suggesting that genomic selection (GS) will be effective both for improving resistance in breeding populations and identifying highly resistant clones as varieties

Genome-Wide Association Mapping of Correlated Traits in Cassava: Dry Matter and Total Carotenoid Content

Article purchased; Published online: 3 August 2017Cassava (Manihot esculenta (L.) Crantz) is a starchy root crop cultivated in the tropics for fresh consumption and commercial processing. Dry matter content and micronutrient density, particularly of provitamin A, traits that are negatively correlated, are among the primary selection objectives in cassava breeding. This study aimed at identifying genetic markers associated with these traits and uncovering the potential underlying cause of their negative correlation - whether linkage and/or pleiotropy. A genome-wide association mapping using 672 clones genotyped at 72,279 SNP loci was carried out. Root yellowness was used indirectly to assess variation in carotenoid content. Two major loci for root yellowness was identified on chromosome 1 at positions 24.1 and 30.5 Mbp. A single locus for dry matter content that co-located with the 24.1 Mbp peak for carotenoid content was identified. Haplotypes at these loci explained a large proportion of the phenotypic variability. Evidence of mega-base-scale linkage disequilibrium around the major loci of the two traits and detection of the major dry matter locus in independent analysis for the white- and yellow-root subpopulations suggests that physical linkage rather that pleiotropy is more likely to be the cause of the negative correlation between the target traits. Moreover, candidate genes for carotenoid (phytoene synthase) and starch biosynthesis (UDP-glucose pyrophosphorylase and sucrose synthase) occurred in the vicinity of the identified locus at 24.1 Mbp. These findings elucidate on the genetic architecture of carotenoids and dry matter in cassava and provides an opportunity to accelerate genetic improvement of these traits

Role of oesophageal cooling in the prevention of oesophageal injury in atrial fibrillation catheter ablation: a systematic review and meta-analysis of randomized controlled trials.

AIMS: To evaluate the efficacy of oesophageal cooling in the prevention of oesophageal injury in patients undergoing atrial fibrillation (AF) catheter ablation. METHODS AND RESULTS: Comprehensive search of MEDLINE, EMBASE, and Cochrane databases through April 2022 for randomized controlled trials (RCTs) evaluating the role of oesophageal cooling compared with control in the prevention of oesophageal injury during AF catheter ablation. The study primary outcome was the incidence of any oesophageal injury. The meta-analysis included 4 RCTs with a total of 294 patients. There was no difference in the incidence of any oesophageal injury between oesophageal cooling and control [15% vs. 19%; relative risk (RR) 0.86; 95% confidence interval (CI) 0.31-2.41]. Compared with control, oesophageal cooling showed lower risk of severe oesophageal injury (1.5% vs. 9%; RR 0.21; 95% CI 0.05-0.80). There were no significant differences among the two groups in mild to moderate oesophageal injury (13.6% vs. 12.1%; RR 1.09; 95% CI 0.28-4.23), procedure duration [standardized mean difference (SMD) -0.03; 95% CI -0.36-0.30], posterior wall radiofrequency (RF) time (SMD 0.27; 95% CI -0.04-0.58), total RF time (SMD -0.50; 95% CI -1.15-0.16), acute reconnection incidence (RR 0.93; 95% CI 0.02-36.34), and ablation index (SMD 0.16; 95% CI -0.33-0.66). CONCLUSION: Among patients undergoing AF catheter ablation, oesophageal cooling did not reduce the overall risk of any oesophageal injury compared with control. Oesophageal cooling might shift the severity of oesophageal injuries to less severe injuries. Further studies should evaluate the long-term effects after oesophageal cooling during AF catheter ablation