Publications by authors named "Dunwei Wang"

94 Publications

Molecular-Level Insights into Selective Transport of Mg in Metal-Organic Frameworks.

ACS Appl Mater Interfaces 2021 Jul 30. Epub 2021 Jul 30.

Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States.

Metal-organic frameworks (MOF) are promising media for achieving solid-state Mg conduction and developing a magnesium-based battery. To this end, the chemical behavior and transport properties of an Mg(TFSI)/DME electrolyte system inside Mg-MOF-74 were studied by density functional theory (DFT). We found that inside the MOF chemical environment, solvent and anion molecules occupy the coordinatively unsaturated open metal sites of Mg-MOF-74, while Mg ions adsorb directly onto the carboxylate group of the MOF organic linker. These predicted binding geometries were further corroborated by IR spectroscopy. We computed the free energies of desolvation of Mg ions inside MOF to investigate the capacity of Mg-MOF-74 thin film to act as a separator for selective Mg transport. We showed that Mg-MOF-74 could facilitate partial, but not full, desolvation of Mg. We found that the dominant minimum-energy pathway (MEP) for Mg conduction inside Mg-MOF-74 corresponds to a "solvent hopping" mechanism, with an energy barrier of 4.4 kcal/mol. The molar conductivity of Mg associated with the idealized solvent hopping mechanism along the MOF one-dimensional channel was predicted to be 2.4 × 10 S cm M, which is one to two orders of magnitude greater than the experimentally measured value of 1.2 × 10 S cm M (with an estimated Mg concentration). We have discussed several possible factors contributing to this apparent discrepancy. The current work demonstrates the validity of the computational strategies applied and the structural models constructed for the understanding of fast and selective Mg transport in Mg-MOF-74, which serves as a cornerstone for studying transport of multivalent ions in MOFs. Furthermore, it provides detailed molecular-level insights that are not yet accessible experimentally.
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http://dx.doi.org/10.1021/acsami.1c08392DOI Listing
July 2021

Electrochemically switchable polymerization from surface-anchored molecular catalysts.

Chem Sci 2021 Jul 28;12(26):9042-9052. Epub 2021 May 28.

Department of Chemistry, Boston College 2609 Beacon St., Chestnut Hill MA 02467 USA

Redox-switchable polymerizations of lactide and epoxides were extended to the solid state by anchoring an iron-based polymerization catalyst to TiO nanoparticles. The reactivity of the molecular complexes and their redox-switching characteristics were maintained in the solid-state. These properties resulted in surface-initiated polymerization reactions that produced polymer brushes whose chemical composition is dictated by the oxidation state of the iron-based complex. Depositing the catalyst-functionalized TiO nanoparticles on fluorine-doped tin oxide resulted in an electrically addressable surface that could be used to demonstrate spatial control in redox-switchable polymerization reactions. By using a substrate that contained two electrically isolated domains wherein one domain was exposed to an oxidizing potential, patterns of surface-bound polyesters and polyethers were accessible through sequential application of lactide and cyclohexene oxide. The differentially functionalized surfaces demonstrated distinct physical properties that illustrated the promise for using the method to pattern surfaces with multiple, chemically distinct polymer brushes.
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http://dx.doi.org/10.1039/d1sc02163jDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261715PMC
July 2021

Introducing special issue on photocatalysis and photoelectrochemistry.

J Chem Phys 2021 May;154(19):190401

Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, USA.

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http://dx.doi.org/10.1063/5.0053681DOI Listing
May 2021

Enabling Lithium Metal Anode in Nonflammable Phosphate Electrolyte with Electrochemically Induced Chemical Reactions.

Angew Chem Int Ed Engl 2021 Aug 9;60(35):19183-19190. Epub 2021 Jun 9.

Department of Chemistry, Boston College, 2609 Beacon St., Chestnut Hill, MA, 02467, USA.

Lithium metal anode holds great promises for next-generation battery technologies but is notoriously difficult to work with. The key to solving this challenge is believed to lie in the ability of forming stable solid-electrolyte interphase (SEI) layers. To further address potential safety issues, it is critical to achieve this goal in nonflammable electrolytes. Building upon previous successes in forming stable SEI in conventional carbonate-based electrolytes, here we report that reversible Li stripping/plating could be realized in triethyl phosphate (TEP), a known flame retardant. The critical enabling factor of our approach was the introduction of oxygen, which upon electrochemical reduction induces the initial decomposition of TEP and produces Li PO and poly-phosphates. Importantly, the reaction was self-limiting, and the resulting material regulated Li plating by limiting dendrite formation. In effect, we obtained a functional SEI on Li metal in a nonflammable electrolyte. When tested in a symmetric Li∥Li cell, more than 300 cycles of stripping/plating were measured at a current density of 0.5 mA cm . Prototypical Li-O and Li-ion batteries were also fabricated and tested to further support the effectiveness of this strategy. The mechanism by which the SEI forms was studied by density functional theory (DFT), and the predictions were corroborated by the successful detection of the intermediates and products.
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http://dx.doi.org/10.1002/anie.202103909DOI Listing
August 2021

miR-140 inhibits osteosarcoma progression by impairing USP22-mediated LSD1 stabilization and promoting p21 expression.

Mol Ther Nucleic Acids 2021 Jun 3;24:436-448. Epub 2021 Feb 3.

Department of Spine Surgery, The First Hospital of Jilin University, Changchun 130021, P.R. China.

Osteosarcoma is a bone tumor frequently diagnosed in children and young adults. Despite advances in chemotherapy and surgical resection, tumors metastasize in 30% of osteosarcoma patients. In addition, side effects caused by chemotherapeutic drugs, as well as the development of chemoresistance, highlight the need to identify the molecular mechanisms involved in the pathogenesis of osteosarcoma. We compared 65 osteosarcoma samples to their adjacent normal tissues, as well as commercially obtained osteosarcoma cell lines with normal osteoblast cell lines, and identified a role for the microRNA (miR)-140/ubiquitin-specific protease 22 (USP22)/lysine-specific demethylase 1 (LSD1)/p21 axis in the development of osteosarcoma. Osteosarcoma tissues and cells exhibited poor miR-140 and p21 expression, whereas the expression of USP22 and LSD1 was increased. Overexpression of miR-140 inhibited cell proliferation, migration, and invasion and promoted cell apoptosis by directly targeting USP22, resulting in its decreased expression. Overexpression of USP22 reversed the effects of miR-140 overexpression in osteosarcoma cells. Overexpression of miR-140 or USP22 knockdown led to the ubiquitination and degradation of LSD1. miR-140 overexpression also suppressed tumorigenesis . This study revealed a role for miR-140 in the restriction of osteosarcoma development and identified miR-140 as a potential target for therapeutic intervention.
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http://dx.doi.org/10.1016/j.omtn.2021.01.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040122PMC
June 2021

Evolution of Surface Oxidation on TaN as Probed by a Photoelectrochemical Method.

ACS Appl Mater Interfaces 2021 Apr 9;13(15):17420-17428. Epub 2021 Apr 9.

Department of Chemistry, Boston College, Merkert Chemistry Center, 2609 Beacon St., Chestnut Hill, Massachusetts 02467, United States.

In this work, we present an in situ method to probe the evolution of photoelectrochemically driven surface oxidation on photoanodes during active operation in aqueous solutions. A standard solution of KFe(CN)-KPi was utilized to benchmark the photocurrent and assess progressive surface oxidation on TaN in various oxidizing solutions. In this manner, a proportional increase in the surface oxygen concentration was detected with respect to oxidation time and further correlated with a continuous decline in the photocurrent. To discern how surface oxidation alters the photocurrent, we experimentally and theoretically explored its impact on the surface carrier recombination and the interfacial hole transfer rates. Our results indicate that the sluggish photocurrent demonstrated by oxidized TaN arises because of changes in both rates. In particular, the results suggest that the N-O replacement present on the TaN surface primarily increases the carrier recombination rate near the surface and to a lesser degree reduces the interfacial hole transfer rate. More generally, this methodology is expected to further our understanding of surface oxidation atop other nonoxide semiconductor photoelectrodes and its impact on their operation.
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http://dx.doi.org/10.1021/acsami.0c21780DOI Listing
April 2021

Electrochemically Triggered Chain Reactions for the Conversion of Furan Derivatives.

Angew Chem Int Ed Engl 2021 03 24;60(14):7534-7539. Epub 2021 Feb 24.

Department of Chemistry, Boston College, Merkert Chemistry Center, 2609 Beacon St., Chestnut Hill, MA, 02467, USA.

We report an electrochemical method for coupling biomass-derived C5/C6 compounds to value-added fuel precursors. Using only 2 % of equivalent charges, 2-methylfuran (2-MF) was oxidized to yield a cation radical, which readily reacted with 3-hexene-2,5-dione, a derivate of 2,5-dimethylfuran, to produce 3-(5-methylfuran-2-yl)hexane-2,5-dione. The product was converted to 4-ethylnonane (a component of biodiesel/jet fuel) in a single step in excellent yield. Importantly, the reaction was not sensitive to oxygen, and a trace amount of water was found to promote the reaction. Detailed mechanistic studies confirmed the proposed reaction pathways. Key to the mechanism is the radical generation that is enabled by electrochemistry. The radical is regenerated at the end of a reaction cycle to ensure chain propagation for an average of ca. 47 times, resulting in an apparent Faradaic efficiency of 4700 %.
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http://dx.doi.org/10.1002/anie.202016601DOI Listing
March 2021

Reactive Oxygen Species Interact With NLRP3 Inflammasomes and Are Involved in the Inflammation of Sepsis: From Mechanism to Treatment of Progression.

Front Physiol 2020 25;11:571810. Epub 2020 Nov 25.

Department of Anesthesiology, First Hospital of Jilin University, Changchun, China.

Over the past 10 years, the crisis of sepsis has remained a great challenge. According to data from 2016, the sepsis-related mortality rate remains high. In addition, sepsis consumes extensive medical resources in intensive care units, and anti-inflammatory agents fail to improve sepsis-associated hyperinflammation and symptoms of immunosuppression. The specific immune mechanism of sepsis remains to be elucidated. Reactive oxygen species (ROS) are triggered by energy metabolism and respiratory dysfunction in sepsis, which not only cause oxidative damage to tissues and organelles, but also directly and indirectly promote NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. NLRP3 inflammasomes enlarge the inflammatory response and trigger apoptosis of immune cells to exacerbate sepsis progression. Inhibiting the negative effects of ROS and NLRP3 inflammasomes therefore provides the possibility of reversing the excessive inflammation during sepsis. In this review, we describe the interaction of ROS and NLRP3 inflammasomes during sepsis, provide prevention strategies, and identify fields that need further study.
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http://dx.doi.org/10.3389/fphys.2020.571810DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723971PMC
November 2020

hsa_circ_0085539 Promotes Osteosarcoma Progression by Regulating miR-526b-5p and SERP1.

Mol Ther Oncolytics 2020 Dec 4;19:163-177. Epub 2020 Oct 4.

Department of Spine Surgery, The First Hospital of Jilin University, No. 71 Xinmin Street, Changchun, Jilin 130021, China.

This study aimed to expand the competing endogenous RNA network in osteosarcoma (OS) involving hsa_circ_0085539 and its downstream target miR-526b-5p. The expression levels of circ_0085539, miR-526b-5p, and stress-associated endoplasmic reticulum protein 1 (SERP1) mRNA in OS tissues and cells were detected and analyzed by qRT-PCR. After that, the interrelationships between these three genetic materials were validated with a luciferase reporter assay system. The effect of the circ_0085539/miR-526b-5p/SERP1 axis on OS cell malignancy phenotypes was further assessed using assays, including cell counting kit-8 (CCK-8) assays, colony foci formation assays, wound-healing migration assays, and transwell invasion assays. To determine the function of circ_0085539 on OS tumor growth , a xenograft formation assay was performed. In OS tissues and cells, the expression of circ_0085539 and SERP1 was upregulated, while that of miR-526b-5p was downregulated. After experimental analyses, it was found that silencing circ_0085539 inhibited the aggression of OS and . Mechanistic investigations also revealed that circ_0085539 could sponge miR-526b-5p and that miR526b-5p could directly target SERP1. The cytological experiments demonstrated that miR-526b-5p could restore the effect of circ_0085539 in terms of promoting OS malignancy phenotypes by suppressing SERP1. Overall, the present study validated that hsa_circ_0085539 could promote the progression of OS by regulating miR-526b-5p/SERP1.
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http://dx.doi.org/10.1016/j.omto.2020.09.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7649436PMC
December 2020

Retraction Note to: Circular RNA ABCB10 promotes hepatocellular carcinoma progression by increasing HMG20A expression by sponging miR-670-3p.

Cancer Cell Int 2020 6;20:485. Epub 2020 Oct 6.

Department of Anesthesiology, The First Hospital of Jilin University, No. 71 Xinmin Street, Changchun, 130021 Jilin People's Republic of China.

[This retracts the article DOI: 10.1186/s12935-019-1055-z.].
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http://dx.doi.org/10.1186/s12935-020-01586-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7539437PMC
October 2020

Continuous Synthesis of Hollow High-Entropy Nanoparticles for Energy and Catalysis Applications.

Adv Mater 2020 Nov 5;32(46):e2002853. Epub 2020 Oct 5.

Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA.

Mixing multimetallic elements in hollow-structured nanoparticles is a promising strategy for the synthesis of highly efficient and cost-effective catalysts. However, the synthesis of multimetallic hollow nanoparticles is limited to two or three elements due to the difficulties in morphology control under the harsh alloying conditions. Herein, the rapid and continuous synthesis of hollow high-entropy-alloy (HEA) nanoparticles using a continuous "droplet-to-particle" method is reported. The formation of these hollow HEA nanoparticles is enabled through the decomposition of a gas-blowing agent in which a large amount of gas is produced in situ to "puff" the droplet during heating, followed by decomposition of the metal salt precursors and nucleation/growth of multimetallic particles. The high active sites per mass ratio of such hollow HEA nanoparticles makes them promising candidates for energy and electrocatalysis applications. As a proof-of-concept, it is demonstrated that these materials can be applied as the cathode catalyst for Li-O battery operations with a record-high current density per catalyst mass loading of 2000 mA g , as well as good stability and durable catalytic activity. This work offers a viable strategy for the continuous manufacturing of hollow HEA nanomaterials that can find broad applications in energy and catalysis.
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http://dx.doi.org/10.1002/adma.202002853DOI Listing
November 2020

NLRP3 inflammasomes are involved in the progression of postoperative cognitive dysfunction: from mechanism to treatment.

Neurosurg Rev 2021 Aug 12;44(4):1815-1831. Epub 2020 Sep 12.

Department of Oncology, First Hospital of Jilin University, Changchun, China.

Postoperative cognitive dysfunction (POCD) involves patient memory and learning decline after surgery. POCD not only presents challenges for postoperative nursing and recovery but may also cause permanent brain damage for patients, including children and the aged, with vulnerable central nervous systems. Its occurrence is mainly influenced by surgical trauma, anesthetics, and the health condition of the patient. There is a lack of imaging and experimental diagnosis; therefore, patients can only be diagnosed by clinical observation, which may underestimate the morbidity, resulting in decreased treatment efficacy. Except for symptomatic support therapy, there is a relative lack of effective drugs specific for the treatment of POCD, because the precise mechanism of POCD remains to be determined. One current hypothesis is that postoperative inflammation promotes the progression of POCD. Accumulating research has indicated that overactivation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to the POCD progression, suggesting that targeting NLRP3 inflammasomes may be an effective therapy to treat POCD. In this review, we summarize recent studies and systematically describe the pathogenesis, treatment progression, and potential treatment options of targeting NLRP3 inflammasomes in POCD patients.
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http://dx.doi.org/10.1007/s10143-020-01387-zDOI Listing
August 2021

High-loading single Pt atom sites [Pt-O(OH) ] catalyze the CO PROX reaction with high activity and selectivity at mild conditions.

Sci Adv 2020 Jun 17;6(25):eaba3809. Epub 2020 Jun 17.

Department of Chemical and Biological Engineering, Tufts University, Medford, MA 02155, USA.

The preferential oxidation of CO (PROX) in hydrogen-rich fuel gas streams is an attractive option to remove CO while effectively conserving energy and H. However, high CO conversion with concomitant high selectivity to CO but not HO is challenging. Here, we report the synthesis of high-loading single Pt atom (2.0 weight %) catalysts with oxygen-bonded alkaline ions that stabilize the cationic Pt. The synthesis is performed in aqueous solution and achieves high Pt atom loadings in a single-step incipient wetness impregnation of alumina or silica. Promisingly, these catalysts have high CO PROX selectivity even at high CO conversion (~99.8% conversion, 70% selectivity at 110°C) and good stability under reaction conditions. These findings pave the way for the design of highly efficient single-atom catalysts, elucidate the role of ─OH species in CO oxidation, and confirm the absence of a support effect for our case.
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http://dx.doi.org/10.1126/sciadv.aba3809DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7299615PMC
June 2020

The efficacy of nerve block for pain control after mammaplasty: a meta-analysis of randomized controlled studies.

J Plast Surg Hand Surg 2020 Aug 12;54(4):195-199. Epub 2020 Jun 12.

Department of Anesthesiology, The First Hospital of Jilin University, Changchun, China.

Nerve block shows some potential in alleviating pain after mammaplasty. This systematic review and meta-analysis aims to investigate the efficacy of nerve block for pain control after mammaplasty. The databases including PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases are systematically searched for collecting the randomized controlled trials (RCTs) regarding the impact of nerve block on pain intensity after mammaplasty. This meta-analysis has included four RCTs. Compared with the control group after mammaplasty, nerve block results in remarkably reduced pain scores. At 1, 3, and 6 h, the scores are -1.84; -2.49 to -1.20 (mean difference (MD; 95% confidence interval (CI));  < .00001, -1.04; -1.47 to -0.62;  < .00001; and -0.96; -1.48 to -0.43;  = .0004, respectively. At 24 h, nerve block shows no significant impact on pain scores: 0.31; -1.05 to 0.43;  = .41. The standard MD of analgesic consumption is significantly reduced after nerve block: -1.27; -1.73 to -0.82;  < .00001. Nerve block is associated with substantially reduced pain intensity at 1 h, 3 h, and 6 h, as well as decreased analgesic consumption after mammaplasty. Therefore, a nerve block is a valuable tool for postoperative care after mammaplasty and should be recommended for the surgery.
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http://dx.doi.org/10.1080/2000656X.2019.1661847DOI Listing
August 2020

Circular RNA ABCB10 promotes hepatocellular carcinoma progression by increasing HMG20A expression by sponging miR-670-3p.

Cancer Cell Int 2019 16;19:338. Epub 2019 Dec 16.

2Department of Anesthesiology, The First Hospital of Jilin University, No. 71 Xinmin Street, Changchun, 130021 Jilin People's Republic of China.

Background/aims: The dysregulation of circABCB10 may play an critical role in tumor progression. However, its function in liver cancer (HCC) is still unclear. Therefore, this experimental design is based on circABCB10 to explore the pathogenesis of HCC.

Methods: The expression of circABCB10 and miR-670-3p in HCC tissues was detected by RT-qPCR. CCK-8, Brdu incorporation, colony formation and transwell assays were used to determine the effect of circABCB10 on HCC cell proliferation and migration. Target gene prediction and screening, luciferase reporter assays were used to validate downstream target genes of circABCB10 and miR-670-3p. HMG20A expression was detected by RT-qPCR and Western blotting. The tumor changes in mice were detected by in nude mice.

Results: CircABCB10 was significantly increased in HCC tissues and cell lines, and high CircABCB10 expression was directly associated with low survival in HCC patients. Silencing of circABCB10 inhibited proliferation and invasion of hepatocellular carcinoma. In addition, circABCB10 acted as a sponge of miR-670-3p to upregulate HMG20A expression. In addition, overexpression of miR-670-3p or knockdown of HMG20A reversed the carcinogenic effects of circABCB10 in HCC. There was a negative correlation between the expression of circABCB10 and miR-670-3p, and a positive correlation between the expression of circABCB10 and HMG20A in HCC tissues.

Conclusion: circABCB10 promoted HCC progression by modulating the miR-670-3p/HMG20A axis, and circABCB10 may be a potential therapeutic target for HCC. JL1H384739, registered at Sep 09, 2014.
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http://dx.doi.org/10.1186/s12935-019-1055-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915995PMC
December 2019

Surface chemistry and photoelectrochemistry-Case study on tantalum nitride.

J Chem Phys 2019 Oct;151(13):130902

Department of Chemistry, Boston College, Merkert Chemistry Center, 2609 Beacon St., Chestnut Hill, Massachusetts 02467, USA.

Solar water splitting promises a solution to challenges associated with the intermittent nature of solar energy. Of different implementations, photoelectrochemical water splitting, where one or more photoelectrodes harvest light and catalyze water splitting, represents a convenient platform to understand the governing principles of charge behaviors, especially at the light absorber|HO interface. This Perspective recognizes and discusses the importance of the photoelectrode surface to solar water splitting performance. It presents discussions within the context of a prototypical water splitting material, TaN, which has gained growing attention lately for its outstanding initial performance. Insights into the mechanisms by which TaN functions are presented, followed by examples of recent efforts to circumvent the issues that TaN decays rapidly under solar water splitting conditions. Our visions on the future directions of semiconductor-based solar water splitting will be presented at the end.
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http://dx.doi.org/10.1063/1.5122996DOI Listing
October 2019

Role of HO in CO Electrochemical Reduction As Studied in a Water-in-Salt System.

ACS Cent Sci 2019 Aug 15;5(8):1461-1467. Epub 2019 Jul 15.

Chemistry Department, Boston College, Chestnut Hill, Massachusetts 02467, United States.

CO electrochemical reduction is of great interest not only for its technological implications but also for the scientific challenges it represents. How to suppress the kinetically favored hydrogen evolution in the presence of HO, for instance, has attracted significant attention. Here we report a new way of achieving such a goal. Our strategy involves a unique water-in-salt electrolyte system, where the HO concentration can be greatly suppressed due to the strong solvation of the high-concentration salt. More importantly, the water-in-salt electrolyte offers an opportunity to tune the HO concentration for electrokinetic studies of CO reduction, a parameter of critical importance to the understanding of the detailed mechanisms but difficult to vary previously. Using Au as a model catalyst platform, we observed a zeroth-order dependence of the reaction rate on the HO concentration, strongly suggesting that electron transfer, rather than concerted proton electron transfer, from the electrode to the adsorbed CO is the rate-determining step. The results shed new light on the mechanistic understanding of CO electrochemical reduction. Our approach is expected to be applicable to other catalyst systems, as well, which will offer a new dimension to mechanistic studies by tuning HO concentrations.
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http://dx.doi.org/10.1021/acscentsci.9b00519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6716197PMC
August 2019

A Metal-Organic Framework Thin Film for Selective Mg Transport.

Angew Chem Int Ed Engl 2019 Oct 13;58(43):15313-15317. Epub 2019 Sep 13.

Department of Chemistry, Boston College, Merkert Chemistry Center, 2609 Beacon St., Chestnut Hill, MA, 02467, USA.

The incompatibility between the anode and the cathode chemistry limits the used of Mg as an anode. This issue may be addressed by separating the anolyte and the catholyte with a membrane that only allows for Mg transport. Mg-MOF-74 thin films were used as the separator for this purpose. It was shown to meet the needs of low-resistance, selective Mg transport. The uniform MOF thin films supported on Au substrate with thicknesses down to ca. 202 nm showed an intrinsic resistance as low as 6.4 Ω cm , with the normalized room-temperature ionic conductivity of ca. 3.17×10  S cm . When synthesized directly onto a porous anodized aluminum oxide (AAO) support, the resulting films were used as a standalone membrane to permit stable, low-overpotential Mg striping and plating for over 100 cycles at a current density of 0.05 mA cm . The film was effective in blocking solvent molecules and counterions from crossing over for extended period of time.
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http://dx.doi.org/10.1002/anie.201908706DOI Listing
October 2019

Understanding photoelectrochemical kinetics in a model CO fixation reaction.

Phys Chem Chem Phys 2019 Aug 5;21(32):17517-17520. Epub 2019 Aug 5.

Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, P. R. China.

Kinetic studies of photo- and photoelectro-catalysis fixation of CO are rare. Herein, a typical CO reduction addition to trans-stilbene is studied. Through Tafel analyses, the reaction rate-determining step (RDS) is identified as the first step of an anion free radical generation from the substrate, and the reaction order is 0.5.
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http://dx.doi.org/10.1039/c9cp03541aDOI Listing
August 2019

Stable Multimetallic Nanoparticles for Oxygen Electrocatalysis.

Nano Lett 2019 08 17;19(8):5149-5158. Epub 2019 Jul 17.

Department of Materials Science and Engineering , University of Maryland , College Park , Maryland 20742 , United States.

Nanostructured catalysts often face an important challenge: poor stability. Many factors contribute to catalytic degradation, including parasitic chemical reactions, phase separation, agglomeration, and dissolution, leading to activity loss especially during long-term catalytic reactions. This challenge is shared by a new family of catalysts, multimetallic nanoparticles, which have emerged owing to their broad tunability and high activity. While significant synthesis-based advances have been made, the stability of these nanostructured catalysts, especially during catalytic reactions, has not been well addressed. In this study, we reveal the critical influence of a synthetic method on the stability of nanostructured catalysts through aprotic oxygen catalysis (Li-O battery) demonstrations. In comparison to the conventional wet impregnation (WI) method, we show that the carbothermal shock (CTS) method dramatically improves the overall structural and chemical stability of the catalyst with the same elemental compositions. For multimetallic compositions (4- and 8-elements), the overall stability of the electrocatalysts as well as the battery lifetime can be further improved by incorporating additional noncatalytically active elements into the individual nanoparticles via CTS. The results offer a new synthetic path toward the stabilization of nanostructured catalysts, where additional reaction schemes beyond oxygen electrocatalysis are foreseeable.
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http://dx.doi.org/10.1021/acs.nanolett.9b01523DOI Listing
August 2019

Severe bradycardia caused by the deviation of the laryngeal mask airway Supreme: A case report.

Medicine (Baltimore) 2019 Jun;98(24):e15904

Department of Anesthesiology, First Hospital of Jilin University, Changchun, Jilin, China.

Rationale: Classic laryngeal mask airway (LMA) has long been used for airway management. The LMA Supreme is a modified single-use version of the LMA Proseal, but it still remains some deficits such as the instable positioning that lead to easily sliding and the mask bowl full of air might lead to the reduced blood flow of the internal carotid artery. The carotid sinus is a baroreceptor that responds to the stretching of the arterial wall. Manual pressure of the carotid artery at the upper margin of the sternocleidomastoid muscle provoked bradycardia and hypotension.

Patient Concerns: A previously fit and well 42-year-old woman presented with breast fibroma on the left side. No other disease history could be recorded. Her family history was negative for neuromuscular and autoimmune disease.

Diagnoses: The patient suffered from a severe bradycardia and hypotension when the LMA showed a shift. We presented with a hypothetical that the dislocated LMA may cause carotid sinus syndrome (CSS).

Interventions: The patient's heart rate (HR) gradually rosed up as soon as the LMA adjusted back to the normal position.

Outcomes: The patient was comfortable in the post anesthesia care unit (PACU) and had no adverse sequelae.

Lessons: The position of LMA Supreme should be confirmed throughout the surgery especially for the ones who has changed the position and the head was covered by surgical drapes.
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http://dx.doi.org/10.1097/MD.0000000000015904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587568PMC
June 2019

Direct Deposition of Crystalline TaN Thin Films on FTO for PEC Water Splitting.

ACS Appl Mater Interfaces 2019 May 22;11(17):15457-15466. Epub 2019 Apr 22.

Department of Chemistry , Michigan State University , 578 S Shaw Lane , East Lansing , Michigan 48824-1322 , United States.

Tantalum nitride is a promising photoanode material for solar water splitting, but further study and practical use are constrained by the harsh conditions of the synthesis from Ta metal. Here, we report the direct deposition of crystalline TaN on fluorine-doped tin oxide (FTO) substrate via a custom-built atomic layer deposition (ALD) system. A combination of TaCl (Ta precursor) and ammonia (N source) was sequentially pulsed into the ALD reactor with the substrate heated to 550 °C to deposit compact and thin films of TaN with controllable thicknesses on FTO substrates. Importantly, it is shown that the FTO is chemically and structurally stable under the reducing conditions of ammonia at 550 °C. These electrodes produced an exceptional photocurrent onset potential of ∼0.3 V versus reversible hydrogen electrode (RHE) with a maximum photocurrent of ∼2.4 mA cm at 1.23 V versus RHE. Results of photoelectrochemical investigations as a function of film thickness and illumination direction reveal that the performance of TaN is controlled by a hole diffusion length of ∼50 nm. These results are crucial for the successful integration of TaN in efficient unassisted water-splitting applications.
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http://dx.doi.org/10.1021/acsami.8b21194DOI Listing
May 2019

Selectivity of HO and O by water oxidation on metal oxide surfaces.

J Chem Phys 2019 Jan;150(4):041712

Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon Street, Chestnut Hill, Massachusetts 02467, USA.

Water oxidation is an important chemical reaction that yields electrons for downstream reduction reactions such as hydrogen generation or CO and/or N reduction. When producing O, the reaction involves 4 electrons and 4 protons and tends to be kinetically unfavored. A competing pathway leading to the formation of HO would only involve 2 electrons and 2 protons and may serve as a favorable alternative to O formation while meeting the needs for electron production by water oxidation. Although HO as a product of water oxidation has been observed experimentally, the bifurcating point that determines whether O or HO is the favored product has not been identified by experiments previously. Here, we report a detailed experimental study aimed at correcting this deficiency. We propose that the ease or difficulty of protonation or deprotonation of -OOH intermediates is a key to the selectivity between HO and O. That is, we hypothesize that the (de)protonation of M-OOH, where M represents an active metal center, is the bifurcating point of the water oxidation catalytic cycle. Ready deprotonation of this intermediate leads to the eventual formation and release of O, whereas the protonation of this intermediate enables the formation of HO. The dependence of product selectivity on pH as observed by quantitative HO detection supports this hypothesis. Additional experimental evidence based on isotope effects is also obtained. The results will likely find broad implications in catalyst design for high-performance water oxidation reactions.
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http://dx.doi.org/10.1063/1.5046886DOI Listing
January 2019

Thin film photoelectrodes for solar water splitting.

Chem Soc Rev 2019 Apr;48(7):2182-2215

Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, Massachusetts 02467, USA.

Photoelectrochemical (PEC) water splitting has been intensively studied in the past decades as a promising method for large-scale solar energy storage. Among the various issues that limit the progress of this field, the lack of photoelectrode materials with suitable properties in all aspects of light absorption, charge separation and transport, and charge transfer is a key challenge, which has attracted tremendous research attention. A large variety of compositions, in different forms, have been tested. This review aims to summarize efforts in this area, with a focus on materials-related considerations. Issues discussed by this review include synthesis, optoelectronic properties, charge behaviors and catalysis. In the recognition that thin-film materials are representative model systems for the study of these issues, we elected to focus on this form, so as to provide a concise and coherent account on the different strategies that have been proposed and tested. Because practical implementation is of paramount importance to the eventual realization of using solar fuel for solar energy storage, we pay particular attention to strategies proposed to address the stability and catalytic issues, which are two key factors limiting the implementation of efficient photoelectrode materials. To keep the overall discussion focused, all discussions were presented within the context of water splitting reactions. How the thin-film systems may be applied for fundamental studies of the water splitting chemical mechanisms and how to use the model system to test device engineering design strategies are discussed.
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http://dx.doi.org/10.1039/c8cs00868jDOI Listing
April 2019

Effect of preoperative smoking cessation on postoperative pain outcomes in elderly patients with high nicotine dependence.

Medicine (Baltimore) 2019 Jan;98(3):e14209

Department of Anesthesiology.

Objective: To investigate the effect of smoking cessation before surgery on postoperative pain and analgesic consumption after thoracoscopic radical resection of lung cancer in elderly patients with high nicotine dependence.

Methods: A total of 107 male patients, ages 60 to 70 years, undergoing elective thoracoscopic radical lung cancer surgery from July 2017 to July 2018 were enrolled into 3 groups: group A (highly nicotine-dependent and discontinued smoking <3 weeks before surgery, n = 36), group B (highly nicotine-dependent and discontinued smoking >3 weeks before surgery, n = 38), and group C (nonsmokers, n = 33). Postoperative sufentanil consumption, visual analog scale (VAS) pain scores at rest and during cough, rescue analgesia, opioid-related adverse events, and patient satisfaction were assessed from 0 to 48 h postoperatively.

Results: Patient characteristics were comparable among the 3 groups. Sufentanil consumption and VAS pain scores from postoperative 0 to 48 h were significantly higher in groups A and B than in group C. In addition, group B had lower sufentanil consumption and pain scores than group A. No differences in the need for rescue analgesia, patient satisfaction, or occurrence of postoperative adverse events, including nausea, vomiting, respiratory depression, and oversedation, were observed among the 3 groups.

Conclusion: Compared with nonsmokers, highly nicotine-dependent male patients who were deprived of cigarettes experienced more severe pain and required treatment with more sufentanil after thoracoscopic radical lung cancer surgery. Moreover, preoperative smoking cessation at least 3 weeks before surgery led to better postoperative pain outcomes than smoking cessation within 3 weeks of surgery.
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http://dx.doi.org/10.1097/MD.0000000000014209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370016PMC
January 2019

A meta-analysis of naldemedine for the treatment of opioid-induced constipation.

Expert Rev Clin Pharmacol 2019 Feb 24;12(2):121-128. Epub 2019 Jan 24.

a Department of Anesthesiology , the First Hospital of Jilin University , Changchun , China.

Introduction: Opioid-induced constipation (OIC) is a common adverse effect in patients under long-term opioid therapy. Naldemedine is a novel peripherally acting μ-opioid receptor antagonists being developed for the treatment of OIC without affecting central analgesia. This meta-analysis is to assess the current evidence for efficacy and safety of naldemedine for the treatment of OIC. Areas covered: We searched through MEDLINE, EMBASE, Web of Science and Cochrane Library, 'ISRCTN Register' and'ClinicalTrials.gov' (up to Aug 2018). Our final review included five randomized clinical trials (1751 participants in total), three trials observed naldemedine for the treatment of OIC in non-cancer patients and two trials in cancer patients. A Random Effects model was used for all comparisons. Subgroup analyses for the following subgroups were carried out: naldemedine 0.1 mg; 0.2 mg; 0.4 mg; cancer patients; non-cancer patients. Expert opinion: Naldemedine improved the proportion of responders and spontaneous bowel movements frequency. The incidence of serious adverse effects (AEs) in naldemedine group was higher than placebo, especially in cancer patient subgroup. The AEs occurred in participants with naldemedine were mild to moderate and well tolerated during treatment. The results of this network meta-analysis will guide the future researchers in evaluating naldemedine for the treatment of OIC.
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http://dx.doi.org/10.1080/17512433.2019.1570845DOI Listing
February 2019

Ultrathin Fe-NiO nanosheets as catalytic charge reservoirs for a planar Mo-doped BiVO photoanode.

Chem Sci 2018 Dec 19;9(47):8860-8870. Epub 2018 Sep 19.

Department of Chemistry , Merkert Chemistry Center , Boston College , 2609 Beacon St., Chestnut Hill , MA 02467 , USA.

The energy conversion efficiency of a photoelectrochemical system is intimately connected to a number of processes, including light absorption, charge excitation, separation and transfer processes. Of these processes, the charge transfer rate at the electrode|electrolyte interface is the slowest and, hence, the rate-limiting step causing charge accumulation. Such an understanding underpins efforts focused on applying highly active electrocatalysts, which may contribute to the overall performance by augmenting surface charge accumulation, prolonging charge lifetime or facilitating charge transfer. How the overall effect depends on these individual possible mechanisms has been difficult to study previously. Aiming at advancing knowledge about this important interface, we applied first-order serial reactions to elucidate the charge excitation, separation and recombination kinetics on the semiconductor|electrocatalyst interfaces in air. The study platform for the present work was prepared using a two-step Mo-doped BiVO film modified with an ultrathin Fe-doped NiO nanosheet, which was derived from an Fe-doped α-Ni(OH) nanosheet by a convenient precipitation and ion-exchange method. The simulation results of the transient surface photovoltage (TSPV) data showed that the surface charge accumulation was significantly enhanced, even at an extremely low coverage (0.12-120 ppm) using ultra-thin Fe-NiO nanosheets. Interestingly, no improvement in the charge separation rate constants or reduction of recombination rate constants was observed under our experimental conditions. Instead, the ultra-thin Fe-NiO nanosheets served as a charge storage layer to facilitate the catalytic process for enhanced performance.
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http://dx.doi.org/10.1039/c8sc03297aDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6296167PMC
December 2018

End-On Bound Iridium Dinuclear Heterogeneous Catalysts on WO for Solar Water Oxidation.

ACS Cent Sci 2018 Sep 25;4(9):1166-1172. Epub 2018 Jul 25.

Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.

Heterogeneous catalysts with atomically defined active centers hold great promise for high-performance applications. Among them, catalysts featuring active moieties with more than one metal atom are important for chemical reactions that require synergistic effects but are rarer than single atom catalysts (SACs). The difficulty in synthesizing such catalysts has been a key challenge. Recent progress in preparing dinuclear heterogeneous catalysts (DHCs) from homogeneous molecular precursors has provided an effective route to address this challenge. Nevertheless, only side-on bound DHCs, where both metal atoms are affixed to the supporting substrate, have been reported. The competing end-on binding mode, where only one metal atom is attached to the substrate and the other metal atom is dangling, has been missing. Here, we report the first observation that end-on binding is indeed possible for Ir DHCs supported on WO. Unambiguous evidence supporting the binding mode was obtained by diffuse reflectance infrared Fourier transform spectroscopy and high-angle annular dark-field scanning transmission electron microscopy. Density functional theory calculations provide additional support for the binding mode, as well as insights into how end-on bound DHCs may be beneficial for solar water oxidation reactions. The results have important implications for future studies of highly effective heterogeneous catalysts for complex chemical reactions.
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http://dx.doi.org/10.1021/acscentsci.8b00335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161057PMC
September 2018

Selective CO Production by Photoelectrochemical Methane Oxidation on TiO.

ACS Cent Sci 2018 May 23;4(5):631-637. Epub 2018 Apr 23.

Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States.

The inertness of the C-H bond in CH poses significant challenges to selective CH oxidation, which often proceeds all the way to CO once activated. Selective oxidation of CH to high-value industrial chemicals such as CO or CHOH remains a challenge. Presently, the main methods to activate CH oxidation include thermochemical, electrochemical, and photocatalytic reactions. Of them, photocatalytic reactions hold great promise for practical applications but have been poorly studied. Existing demonstrations of photocatalytic CH oxidation exhibit limited control over the product selectivity, with CO as the most common product. The yield of CO or other hydrocarbons is too low to be of any practical value. In this work, we show that highly selective production of CO by CH oxidation can be achieved by a photoelectrochemical (PEC) approach. Under our experimental conditions, the highest yield for CO production was 81.9%. The substrate we used was TiO grown by atomic layer deposition (ALD), which features high concentrations of Ti species. The selectivity toward CO was found to be highly sensitive to the substrate types, with significantly lower yield on P25 or commercial anatase TiO substrates. Moreover, our results revealed that the selectivity toward CO also depends on the applied potentials. Based on the experimental results, we proposed a reaction mechanism that involves synergistic effects by adjacent Ti sites on TiO. Spectroscopic characterization and computational studies provide critical evidence to support the mechanism. Furthermore, the synergistic effect was found to parallel heterogeneous CO reduction mechanisms. Our results not only present a new route to selective CH oxidation, but also highlight the importance of mechanistic understandings in advancing heterogeneous catalysis.
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http://dx.doi.org/10.1021/acscentsci.8b00130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5968511PMC
May 2018

Facet-Dependent Kinetics and Energetics of Hematite for Solar Water Oxidation Reactions.

ACS Appl Mater Interfaces 2019 Feb 24;11(6):5616-5622. Epub 2018 May 24.

Department of Chemistry, Merkert Chemistry Center , Boston College , 2609 Beacon Street , Chestnut Hill , Massachusetts 02467 , United States.

The performance of a photoelectrochemical (PEC) system is highly dependent on the charge separation, transport and transfer characteristics at the photoelectrode|electrolyte interface. Of the factors that influence the charge behaviors, the crystalline facets of the semiconductor in contact with the electrolyte play an important role but has been poorly studied previously. Here, we present a study aimed at understanding how the different facets of hematite affect the charge separation and transfer behaviors in a solar water oxidation reaction. Specifically, hematite crystallites with predominantly {012} and {001} facets exposed were synthesized. Density functional theory (DFT) calculations revealed that hematite {012} surfaces feature higher OH coverage, which was confirmed by X-ray photoelectron spectroscopy (XPS). These surface OH groups act as active sites to mediate water oxidation reactions, which plays a positive role for the PEC system. These surface OH groups also facilitate charge recombination, which compromises the charge separation capabilities of hematite. Indeed, intensity modulated photocurrent spectroscopy (IMPS) confirmed that hematite {012} surfaces exhibit higher rate constants for both charge transfer and recombination. Open circuit potential (OCP) measurements revealed that the hematite {012} surface exhibits a greater degree of Fermi level pinning effect. Our results shed light on how different surface crystal structures may change surface kinetics and energetics. The information is expected to contribute to efforts on optimizing PEC performance for practical solar fuel synthesis.
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http://dx.doi.org/10.1021/acsami.8b05190DOI Listing
February 2019
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