Reductive C−C Coupling from α,β‐Unsaturated Nitriles by Intercepting Keteniminates

We present an atom‐economic strategy to catalytically generate and intercept nitrile anion equivalents using hydrogen transfer catalysis. Addition of α,β‐unsaturated nitriles to a pincer‐based Ru−H complex affords structurally characterized κ‐N‐coordinated keteniminates by selective 1,4‐hydride transfer. When generated in situ under catalytic hydrogenation conditions, electrophilic addition to the keteniminate was achieved using anhydrides to provide α‐cyanoacetates in high yields. This work represents a new application of hydrogen transfer catalysis using α,β‐unsaturated nitriles for reductive C−C coupling reactions.An atom‐economic strategy to catalytically generate and intercept nitrile anion equivalents by hydrogen transfer catalysis has been developed. Addition of α,β‐unsaturated nitriles to a pincer‐based Ru−H complex affords keteniminates by selective 1,4‐hydride transfer, which were employed in a net hydrogenative acylation reaction.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149503/1/anie201904530.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149503/2/anie201904530-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149503/3/anie201904530_am.pd

Landfill gas generation and methane recovery at Naboro landfill, Fiji Islands: a case study from a developing Pacific Island country

The Naboro landfill in Suva, the capital city of Fiji Islands, is a sanitary engineered landfill, consisting of a compacted clay protective liner and leachate collection system. The waste is selectively placed, compacted and then covered with soil. The landfill was commisioned in 2005 and is currently receiving an average of 70,000 tonnes of waste annually. The municipal solid waste deposited in the landfill undergoes anaerobic decomposition and the methane gas generated escapes into the atmosphere, adding to the national greenhouse gas inventory. Currently there are no methane recovery and biogas utilisation technology in place or methane flaring at the Naboro landfill site. A feasibility study was carried out recently and based on the model output and field experiments, it was noted that methane recovery and utilisation could be a viable option although there could be some challenges associated with it. According to the waste chaacterization data supplied by the landfill operator it was noted that 83% is house hold waste, 11% is garden waste and 5% is food waste and 1% construction and demolition waste. Based on the type of waste deposited and the tropical weather condition it was calculated using the model that approximately 800 m3/h of methane is generated in 2016. Figure below shows the landfill gas generated at the Naboro landfill from stage 1 to stage 4. Due to tropical humid weather condition and waste rich is organic waste that decomposes rapidly results in the yearly average emission of 74% of total methane generated despite methane recovery via vertical wells installed at the end of each stage. The emission equates to 47,000 tons of CO2 equivalent per year despite methane recovery. The emission can be reduced if the methane generated could be extracted using vertical recovery wells half way through each stage rather than at the end of each stage and as a consequence a slight decrease in yearly average emissions of 41,000 tons of CO2 equivalent were noted. Another approach is to lay horizontal wells as the waste is compacted in the active cell and this could increase the efficiency of landfill gas extraction. The model result indicate that the use of horizontal wells reduces the yearly average emission to 55% of total methane generated. This highlights the fact that approximately 45 % of the methane generated could be harnessed and could be utilized to generate energy using gas engines. However a large fraction of the methane generated is still lost as emission to the atmopshere and this can be further reduced by enhancing the oxdising capacity of the soil cover. The methane oxidation in cover soil was measured to be 10.3% by measuring the CH4-CO2 ratios in the static chamber measurements. The experimental value is close to the IPCC default value of 10%. The paper will discuss other challenges associated with methane recovery at Naboro landfill particularly with landfill gas management

Resolvins: A Family of Bioactive Products of Omega-3 Fatty Acid Transformation Circuits Initiated by Aspirin Treatment that Counter Proinflammation Signals

Aspirin (ASA) is unique among current therapies because it acetylates cyclooxygenase (COX)-2 enabling the biosynthesis of R-containing precursors of endogenous antiinflammatory mediators. Here, we report that lipidomic analysis of exudates obtained in the resolution phase from mice treated with ASA and docosahexaenoic acid (DHA) (C22:6) produce a novel family of bioactive 17R-hydroxy-containing di- and tri-hydroxy-docosanoids termed resolvins. Murine brain treated with aspirin produced endogenous 17R-hydroxydocosahexaenoic acid as did human microglial cells. Human COX-2 converted DHA to 13-hydroxy-DHA that switched with ASA to 17R-HDHA that also proved a major route in hypoxic endothelial cells. Human neutrophils transformed COX-2-ASA–derived 17R-hydroxy-DHA into two sets of novel di- and trihydroxy products; one initiated via oxygenation at carbon 7 and the other at carbon 4. These compounds inhibited (IC50 ∼50 pM) microglial cell cytokine expression and in vivo dermal inflammation and peritonitis at ng doses, reducing 40–80% leukocytic exudates. These results indicate that exudates, vascular, leukocytes and neural cells treated with aspirin convert DHA to novel 17R-hydroxy series of docosanoids that are potent regulators. These biosynthetic pathways utilize omega-3 DHA and EPA during multicellular events in resolution to produce a family of protective compounds, i.e., resolvins, that enhance proresolution status

The Impact of Natural Ventilation During Winter on Thermal Comfort: A systematic literature review

The COVID-19 pandemic has highlighted the importance of ventilation as a transmission mitigation strategy. However, there is a widely-held concern that a drop in outdoor temperatures during wintertime may impact thermal comfort in the context of naturally ventilated classrooms. This is a concern which has not been widely investigated by peer-reviewed empirical studies. The aim of this paper is to review the available literature on the impact of natural ventilation during winter on thermal comfort. Using the replicable search processes of a systematic literature review adopted from medical research practice, 142 articles were retrieved from four search databases (Science direct, Scopus, PubMed, and Google Scholar). Analysis of these 142 articles revealed that most studies have particularly focused on the assessment of ventilation conditions, especially in non-naturally ventilated spaces, and that there were only 5 articles that empirically investigated the impact of natural ventilation on thermal comfort during winter in sufficient detail. This shows a significant gap within the body of literature, meaning that the findings from this study can only be treated as tentative, with further research required

Classroom Ventilation: The Effectiveness of Preheating and Refresh Breaks: An analysis of 169 spaces at 43 schools across New Zealand

The COVID-19 pandemic has highlighted the importance of ventilation as a transmission mitigation strategy. However, there was a widely held concern that a drop in outdoor temperatures during winter may impact thermal comfort in the context of naturally ventilated classrooms. This concern has not been widely investigated by peer-reviewed empirical studies (Sutherland et al., 2022b). The aim of the Ministry’s ventilation monitoring initiative was to assess ventilation performance and thermal comfort by continuously measuring indoor CO2 levels, air temperature, and relative humidity in classrooms during winter, without obstructing teaching activities. A total of 43 schools, which represent a broad mix of property attributes and located across the 6 Climate Zones in New Zealand, were selected for the monitoring initiative. The CO2 monitors were deployed in about 4-6 pre-selected and representative spaces in each school. Data was retrieved from 213 spaces; of these, 44 spaces were excluded, because the initiative concentrated on teaching environments (classrooms) and those spaces were categorised as non-teaching environments (e.g., staff rooms, meeting rooms, etc.). From the 213 spaces, the data from 169 teaching spaces retrieved for the period 23 May to 26 August 2022 were analysed to ascertain the impacts of inferred human behaviours considered to be able to improve natural ventilation and detected from features of CO2 and temperature data. This analysis does not (and did not intend to) corroborate independent observation of behaviours

Profile of Lipid and Protein Autacoids in Diabetic Vitreous Correlates With the Progression of Diabetic Retinopathy

OBJECTIVE: This study was aimed at obtaining a profile of lipids and proteins with a paracrine function in normal and diabetic vitreous and exploring whether the profile correlates with retinal pathology. RESEARCH DESIGN AND METHODS: Vitreous was recovered from 47 individuals undergoing vitreoretinal surgery: 16 had nonproliferative diabetic retinopathy (NPDR), 15 had proliferative diabetic retinopathy, 7 had retinal detachments, and 9 had epiretinal membranes. Protein and lipid autacoid profiles were determined by protein arrays and mass spectrometry-based lipidomics. RESULTS: Vitreous lipids included lipoxygenase (LO)- and cytochrome P450 epoxygenase (CYP)-derived eicosanoids. The most prominent LO-derived eicosanoid was 5-hydroxyeicosate traenoic acid (HETE), which demonstrated a diabetes-specific increase (P = 0.027) with the highest increase in NPDR vitreous. Vitreous also contained CYP-derived epoxyeicosatrienoic acids; their levels were higher in nondiabetic than diabetic vitreous (P < 0.05). Among inflammatory, angiogenic, and angiostatic cytokines and chemokines, only vascular endothelial growth factor (VEGF) showed a significant diabetes-specific profile (P < 0.05), although a similar trend was noted for tumor necrosis factor (TNF)-alpha. Soluble VEGF receptors R1 and R2 were detected in all samples with lowest VEGF-R2 levels (P < 0.05) and higher ratio of VEGF to its receptors in NPDR and PDR vitreous. CONCLUSIONS: This study is the first to demonstrate diabetes-specific changes in vitreous lipid autacoids including arachidonate and docosahexanoate-derived metabolites indicating an increase in inflammatory versus anti-inflammatory lipid mediators that correlated with increased levels of inflammatory and angiogenic proteins, further supporting the notion that inflammation plays a role the pathogenesis of this disease

Identification of a DMBT1 polymorphism associated with increased breast cancer risk and decreased promoter activity

According to present estimations, the unfavorable combination of alleles with low penetrance but high prevalence in the population might account for the major part of hereditary breast cancer risk. Deleted in Malignant Brain Tumors 1 (DMBT1) has been proposed as a tumor suppressor for breast cancer and other cancer types. Genomewide mapping in mice further identified Dmbt1 as a potential modulator of breast cancer risk. Here, we report the association of two frequent and linked single-nucleotide polymorphisms (SNPs) with increased breast cancer risk in women above the age of 60 years: DMBT1 c.-93C>T, rs2981745, located in the DMBT1 promoter; and DMBT1 c.124A>C, p.Thr42Pro, rs11523871(odds ratio [OR]=1.66, 95% confidence interval [CI]=1.21-2.29, P=0.0017; and OR=1.66; 95% CI=1.21-2.28, P=0.0016, respectively), based on 1,195 BRCA1/2 mutation-negative German breast cancer families and 1,466 unrelated German controls. Promoter studies in breast cancer cells demonstrate that the risk-increasing DMBT1 -93T allele displays significantly decreased promoter activity compared to the DMBT1 -93C allele, resulting in a loss of promoter activity. The data suggest that DMBT1 polymorphisms in the 5'-region are associated with increased breast cancer risk. In accordance with previous results, these data link decreased DMBT1 levels to breast cancer risk