Nitrate Radical Facilitates Indirect Benzyl Alcohol Oxidation on Bismuth(III) Vanadate Photoelectrodes

Bismuth(III) vanadate (BiVO4) films show activity for direct benzyl alcohol (PhCH2OH) oxidation to benzaldehyde (PhCHO) in acetonitrile solvent. Introducing tetrabutylammonium nitrate (Bu4NNO3) drastically reduces the overpotential required to generate the PhCHO product while maintaining a high faradaic efficiency (FE) >90 %. BiVO4 corrosion accompanies PhCH2OH oxidation. However, the presence of nitrate ions (NO3−) results in significantly less bismuth‐ and vanadium‐ion leaching (determined by ICP‐MS analysis), as well as reduced surface roughening (determined by SEM imaging). In this reaction, it is proposed that rate‐determining NO3− oxidation generates a highly reactive nitrate radical (NO3⋅) that reacts with PhCH2OH by hydrogen‐atom abstraction (HAT). NO3− is stoichiometrically consumed by the irreversible formation of electrochemically inert HNO3, characterized by an ECi mechanism, rather than a catalytic EC′ mechanism. In the presence of PhCH2OH, NO3− oxidation on BiVO4 becomes more facile; every order of magnitude increase in PhCH2OH concentration shifts the NO3−/ NO3⋅ equilibrium potential negatively by 200 mV. The shift results from the introduction of a consumption pathway for the nitrate radical intermediate via a coupled chemical step with benzyl alcohol. This report is the first example of photoelectrochemical NO3⋅ generation to initiate indirect PhCH2OH oxidation.Initiate to generate: Bismuth(III) vanadate (BiVO4) films show activity for direct benzyl alcohol (PhCH2OH) oxidation to benzaldehyde (PhCHO) in acetonitrile solvent. Introducing tetrabutylammonium nitrate (Bu4NNO3) drastically reduces the overpotential required to generate the PhCHO product while maintaining a high faradaic efficiency. BiVO4 corrosion accompanies PhCH2OH oxidation. Moreover, the presence of nitrate ions (NO3−) results in significantly less bismuth‐ and vanadium‐ion leaching as well as reduced surface roughening.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162788/3/celc202000911.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162788/2/celc202000911-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162788/1/celc202000911_am.pd

Molybdenum Complexes of Chiral C2-symmetric Picchxn-type Ligands: Synthesis, Characterization, and Structural Studies

A series of molybdenum complexes based on chiral C2-symmetric picchxn-type ligands (N4 ligands, defined as trans-N,N′-bis(heterocycl-2-ylmethyl)-1,2-diaminocyclohexanes) has been synthesized and characterized. Reported and novel picchxn-type ligands form (κ3-N4)Mo(CO)3, [(κ4-N4)Mo(NO)(CO)]PF6, and [(κ4-N4)Mo(NO)X]PF6 (X = Br, I) compounds. Multiple tridentate (κ3) and tetradentate (κ4) ligand configurations were observed, and the favored κ4 configuration was found to vary with N4 heterocycle identity. Heterocycle variation allowed for directed modification of the molybdenum electronic characteristics, but none of the studied {(κ4-N4)Mo(NO)}+ fragments was found to be a suitable π-base for dearomatization chemistry. The crystal structures of eight molybdenum complexes with picchxn-type ligands were determined

Comprehensive User Engagement Sites (CUES): Is This a Viable Option for the Opioid Epidemic in Philadelphia?

INTRODUCTION: Opioid drug abuse has become an increasing concern throughout the United States, especially within the Philadelphia region. In 2017, the number of deaths by drug overdose were four times that of deaths by homicide. In addition, a total of 935 cases of secondary conditions due to needle sharing such as HIV and HCV occurred during the past year. The opioid epidemic has caused a public health emergency and any measures that could decrease the morbidity and mortality associated with opioid abuse are vital. A current proposal to combat this issue in Philadelphia is the implementation of a Comprehensive User Engagement Site (CUES); a site intended to offer medical resources and assistance for opioid users. This study analyzed the clinical, ethical, and economic considerations associated with a potential CUES site in Philadelphia. METHODS: A review of the literature was conducted using PubMed, EMBASE, and various public data sources. Search keywords included the history and efficacy of safe injection facilities (SIFs), their implementation to Philadelphia, and other related terms. Semi-structured discussion sessions were also conducted among members of the Institute of Clinical Bioethics at Saint Joseph’s University, resident physicians at Mercy Health System, and PCOM medical students. Topics of discussion included the risks, benefits, and ethics involved in initiating a CUES in Philadelphia, with research regarding past SIFs being uses as a comparative model. RESULTS: The impact of a CUES in Philadelphia has been estimated to avert 3-48 cases of HIV infections annually, 15-213 cases of HCV infections annually, and between 24-76 deaths. In addition, the site is estimated to reduce costs due to skin infection by $1.5-1.9 Million annually, costs due to overdose deaths by upwards of$75 Million annually, as well as costs related to ambulance and hospital visits by $123,000 and$300,000 per averted case respectively. Ethical analysis revealed that safe injection is ethically permissible given the primary intent is to limit the user’s exposure to harm. DISCUSSION: The implementation of a CUES in Philadelphia may be an effective tool to address opioid crisis. It would reduce healthcare costs through prevention of drug-related sequelae, offer treatment and resources for people seeking to overcome their opioid dependence, and act as an educational opportunity for future healthcare professionals by promoting student engagement with marginalized populations

The risk of progression to type 1 diabetes is highly variable in individuals with multiple autoantibodies following screening

Aims/hypothesis: Young children who develop multiple autoantibodies (mAbs) are at very high risk for type 1 diabetes. We assessed whether a population with mAbs detected by screening is also at very high risk, and how risk varies according to age, type of autoantibodies and metabolic status. Methods: Type 1 Diabetes TrialNet Pathway to Prevention participants with mAbs (n = 1815; age, 12.35 ± 9.39 years; range, 1-49 years) were analysed. Type 1 diabetes risk was assessed according to age, autoantibody type/number (insulin autoantibodies [IAA], glutamic acid decarboxylase autoantibodies [GADA], insulinoma-associated antigen-2 autoantibodies [IA-2A] or zinc transporter 8 autoantibodies [ZnT8A]) and Index60 (composite measure of fasting C-peptide, 60 min glucose and 60 min C-peptide). Cox regression and cumulative incidence curves were utilised in this cohort study. Results: Age was inversely related to type 1 diabetes risk in those with mAbs (HR 0.97 [95% CI 0.96, 0.99]). Among participants with 2 autoantibodies, those with GADA had less risk (HR 0.35 [95% CI 0.22, 0.57]) and those with IA-2A had higher risk (HR 2.82 [95% CI 1.76, 4.51]) of type 1 diabetes. Those with IAA and GADA had only a 17% 5 year risk of type 1 diabetes. The risk was significantly lower for those with Index60 <1.0 (HR 0.23 [95% CI 0.19, 0.30]) vs those with Index60 values ≥1.0. Among the 12% (225/1815) ≥12.0 years of age with GADA positivity, IA-2A negativity and Index60 <1.0, the 5 year risk of type 1 diabetes was 8%. Conclusions/interpretation: Type 1 diabetes risk varies substantially according to age, autoantibody type and metabolic status in individuals screened for mAbs. An appreciable proportion of older children and adults with mAbs appear to have a low risk of progressing to type 1 diabetes at 5 years. With this knowledge, clinical trials of type 1 diabetes prevention can better target those most likely to progress

A segmental radiological study of the spine and rib – cage in children with progressive Infantile Idiopathic Scoliosis

BACKGROUND: The role of rib cage in the development of progressive infantile idiopathic scoliosis (IIS) has not been studied previously. No report was found for rib growth in children with IIS. These findings caused us to undertake a segmental radiological study of the spine and rib-cage in children with progressive IIS. The aim of the present study is to present a new method for assessing the thoracic shape in scoliotics and in control subjects and to compare the findings between the two groups. MATERIALS AND METHODS: In the posteroanterior (PA) spinal radiographs of 24 patients with progressive IIS, with a mean age of 4.1 years old, the Thoracic Ratios (TRs) (segmental convex and concave TRs), the Cobb angle, the segmental vertebral rotation and vertebral tilt were measured. In 233 subjects, with a mean age of 5.1 years old, who were used as a control group, the segmental left and right TRs and the total width of the chest (left plus right TRs) were measured in PA chest radiographs. Statistical analysis included Mann-Whitney, Spearman correlation coefficient, multiple linear regression analysis and ANOVA. RESULTS: The comparison shows that the scoliotic thorax is significantly narrower than that of the controls at all spinal levels. The upper chest in IIS is funnel-shaped and the vertebral rotation at T4 early in management correlates significantly with the apical vertebral rotation at follow up. CONCLUSION: The IIS thorax is narrower than that of the controls, the upper chest is funnel-shaped and there is a predictive value of vertebral rotation at the upper limit of the thoracic curve of IIS, which reflects, impaired rib control of spinal rotation possibly due to neuromuscular factors, which contribute also to the funnel-shaped chest

Vaudeville U.S.A.

https://cornerstone.lib.mnsu.edu/university-archives-msu-authors/1161/thumbnail.jp

Selective conversion of CO2 to fuel precursors using an inexpensive bismuth-based electrocatalyst

Rosenthal, JoelHeterogeneous electrochemical reduction of CO2 to CO, which can be coupled to liquid fuel production, provides a pathway to address current issues in solar energy storage. Precious metals such as silver and gold have been found to be active cathodes for this reaction with high current densities and energy efficiencies. However, the price of these materials prohibits their use on the scale required for widespread solar fuel production. By comparison, bismuth represents an inexpensive and environmentally benign metal, whose CO2 chemistry has been largely unexplored. To further characterize the electrocatalytic ability of bismuth materials, we have prepared bismuth modified electrodes from either an ex situ or in situ deposition procedure. These bismuth-based carbon monoxide evolving catalyst (Bi-CMEC) platforms can be easily prepared and display high energy efficiency for the conversion of CO2 to CO in the presence of an imidazolium ([IM]+) based ionic liquid (IL). The kinetics and efficiency with which Bi-CMEC drives electroreduction of CO2 is comparable to that observed using expensive precious metals, with Faradaic efficiencies and current densities for CO production of FECO ~ 80% and jCO ~ 5–30 mA/cm2, respectively at applied overpotentials (η) of ~ 300 mV. By adopting the Bi-CMEC deposition technique, we have developed a general method to prepare Sn, Bi, Pb, and Sb films from their respective triflate salts in MeCN solutions. The ability of the four materials to reduce CO 2 in the presence of IL was probed. Displaying similar electrocatalytic features as Bi, the Sn deposited material is identified as an efficient platform for CO evolution with jCO ~ 5 mA/cm2 at η ~ 300 mV. Neither the Sb nor Pb modified materials were found to be robust platforms for CO evolution. These results highlight that critical interactions occur between the electrode surface, the [IM]+ IL, and CO2. Using rotating disk electrode voltammetry, electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy, we have worked to reveal the primary factors that lead to CO generation by the Bi–[IM] + system. These experiments suggest that pre-organization of [IM] + ions at the electrode/electrolyte interface facilitates rate-limiting CO2 reduction to CO2•–. Further, impedance measurements predict that the formation of Bi–CO2---[IM] + adsorbates is key for minimizing the resistances associated with CO2 reduction. The [IM]+ cations are also shown to provide the protons necessary for the proton-coupled electron transfer (PCET) reduction of CO2. While high proton availability is necessary for PCET, non-[IM]+ proton donors of similar acidity such as 2,2,2-trifluroeothanol (TFE) are unable to promote the efficient evolution of CO at Bi surfaces. Impedance and surface analysis suggests that unlike [IM]+, TFE does not form the necessary stabilizing adsorbates. Instead, TFE can work cooperatively with dilute IL solutions to promote the in situ regeneration of [IM]+, permitting CO evolution at IL concentrations that have previously been prohibitively low. As part of our ongoing efforts to understand the nature of the Bi-IL system, we have isolated a series of cyanoalkyl and fluoroalkyl [IM] + ILs. Incorporation of these electron withdrawing groups increases the ILs proton donating ability and allows for the PCET reduction of CO 2 to occur at potentials ~300 mV more positive. While providing a more acidic environment, functionalization with cyanoalkyl groups inadvertently destabilized the [IM]+ to reductive decomposition, limiting the usefulness of [IM]+ functionalization. As an alternative to [IM]+, we have identified the conjugate acid of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), [DBU–H]+, as a promising IL for the reduction of CO2. Electrolysis of [DBU-H]+ using a bismuth electrode promotes the reduction of CO2 to yield predominantly formate (HCOO –, FA) with FEFA ~ 70% at j tot ~ 20–50 mA/cm2 while suppressing CO production (FECO ~ 20%) in either MeCN or MeCN/H2O (95:5) solutions. These results highlight the versatility of bismuth–IL systems for non-aqueous electrochemical CO2 reduction.University of Delaware, Department of Chemistry and BiochemistryPh.D

Interplay of Corrosion and Photocatalysis During Nonaqueous Benzylamine Oxidation on Cadmium Sulfide

The photo­(electro)­chemical properties of bulk, nanowire, and chemical bath deposits of cadmium sulfide (CdS) for benzylamine oxidation to <i>N</i>-benzylidenebenzylamine (<i>N</i>-BB) in acetonitrile have been evaluated as a model for the activity and stability of CdS toward selective organic oxidations. CdS photocatalysts selectively deliver <i>N</i>-BB at rates ranging from 5 to 26 mM h^–1. Although CdS is a capable photocatalyst, SEM imaging and XPS analysis reveal significant morphological and compositional changes to the particles upon photolysis in benzylamine. These surface changes and surface sulfide oxidation are accompanied by Cd²⁺ leaching and hydrogen sulfide evolution, highlighting both redox and acid–base pathways of nonaqueous CdS corrosion. All facets of corrosion have been linked directly with amine reactivity, as the CdS particles are unaffected by substrate-free photolysis. A series of experiments using <i>N</i>,<i>N</i>-dimethylbenzylamine, 4-<i>N</i>,<i>N</i>-trimethylaniline, and ferrocene show that nonaqueous CdS corrosion is facilitated by acidic reaction intermediates opposed to photogenerated holes. Additionally, water and oxygen are essential components to corrosion, as photoelectrochemistry under dry/air-free conditions displays higher and stable photocurrent density as well as material stability. Finally, CdS nanowires display improved corrosion resistance, suggesting that control of particle morphology and/or electronic structure is essential for developing novel chalcogenide photocatalysts