A Phase Ib study of ruxolitinib + gemcitabine ± nab-paclitaxel in patients with advanced solid tumors.

PubMed

Bauer, Todd M; Patel, Manish R; Forero-Torres, Andres; George, Thomas J; Assad, Albert; Du, Yining; Hurwitz, Herbert

2018-01-01

Aberrant activation of the Janus-associated kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is associated with increased malignant cell proliferation and survival. This Phase Ib study evaluated ruxolitinib, a potent JAK1/2 inhibitor, in combination with gemcitabine with or without nab-paclitaxel in patients with advanced solid tumors. Patients received ruxolitinib + gemcitabine (regimen A) or ruxolitinib + gemcitabine + nab-paclitaxel (regimen B). The objective of the dose-finding phase was to identify the maximum tolerated doses (MTDs) of ruxolitinib plus gemcitabine with or without nab-paclitaxel. Among 42 patients enrolled, the median age was 62.5 years, 81.0% had pancreatic cancer, and almost 62% had received prior systemic therapy. Regimen A was tolerated with standard doses of gemcitabine; regimen B was tolerated with reduced doses of gemcitabine/nab-paclitaxel or concomitant granulocyte colony-stimulating factor. The sponsor decided to terminate the study early due to the interim analysis results of the Phase III JANUS 1 study. Discontinuations were mainly due to radiologic or clinical disease progression (81.0% of patients). Median treatment durations were 55.5 days (cohort A0) and 150.5 days (pooled B cohorts). Four patients (pooled B cohorts) had dose-limiting toxicities: grade 3 pneumonia (n=1), grade 4 neutropenia (n=1), and grade 4 thrombocytopenia (n=2). The most common grade 3/4 hematologic adverse events (AEs) were anemia, thrombocytopenia, and neutropenia. Serious AEs occurring in ≥2 patients in cohort A0 or pooled B cohorts were abdominal pain, sepsis (cohort A0), dehydration, anemia, and asthenia (pooled B cohorts). Overall response rates (ORRs) were 12.5% in cohort A0 and 38.5% in pooled B cohorts. Among patients with pancreatic cancer, ORR was 23.5% (14.0% cohort A0 30.0% pooled B cohorts). The study was terminated early prior to reaching MTDs per sponsor decision; although ruxolitinib plus gemcitabine with or without nab-paclitaxel was generally safe and well tolerated in patients with advanced solid tumors, this combination will not be pursued further.

Membrane electrode assembly fabricated with the combination of Pt/C and hollow shell structured-Pt-SiO2@ZrO2 sphere for self-humidifying proton exchange membrane fuel cell

NASA Astrophysics Data System (ADS)

Ko, Y. D.; Yang, H. N.; Züttel, Andreas; Kim, S. D.; Kim, W. J.

2017-11-01

The Pt-supported hollow structured Pt-HZrO2 with the shell thickness of 27 nm is successfully synthesized. The water retention ability of Pt-HZrO2 is significantly enhanced compared with that of SiO2@ZrO2 due to the hydrophilic hollow structured HZrO2with high BET surface area. Pt-C and Pt-HZrO2 are combined with different weight fractions to prepare the double catalyst electrode (DCE). The membrane electrode assembly with the DCE is fabricated and applied to both anode and cathode or anode side only. The water flooding and thus rapid voltage drop is affected by the presence/or absence of the DCE at the cathode side. The cell test and visual experiment suggests that the Pt-HZrO2 layer adsorb the water molecules generated by the oxygen reduction reaction (ORR), preventing the water flooding. The power generation under RH 0% strongly suggests the back-diffusion of water molecules generated by the ORR. The flow rate to the cathode significantly affects the water flooding and cell performance. Higher flow rate to the cathode is advantageous to expel the water generated by the ORR, thus preventing water flooding and enhancing the cell performance. Therefore, the weight fraction of Pt-C to Pt-HZrO2 and the flow rate to the cathode should be well balanced.

Induction regimens for transplant-eligible patients with newly diagnosed multiple myeloma: a network meta-analysis of randomized controlled trials

PubMed Central

Zeng, Zi-Hang; Chen, Jia-Feng; Li, Yi-Xuan; Zhang, Ran; Xiao, Ling-Fei; Meng, Xiang-Yu

2017-01-01

Objective The aim of this study was to compare the early efficacy and survivals of induction regimens for transplant-eligible patients with untreated multiple myeloma. Materials and methods A comprehensive literature search in electronic databases was conducted for relevant randomized controlled trials (RCTs). Eligible studies were selected according to the predefined selection criteria, before they were evaluated for methodological quality. Basic characteristics and data for network meta-analysis (NMA) were extracted from included trials and pooled in our meta-analysis. The end points were the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results A total of 14 RCTs that included 4,763 patients were analyzed. The post-induction ORR was higher with bortezomib plus thalidomide plus dexamethasone (VTD) regimens, and VTD was better than the majority of other regimens. For OS, VTD plus cyclophosphamide (VTDC) regimens showed potential superiority over other regimens, but the difference was not statistically significant. The PFS was longer with thalidomide plus doxorubicin plus dexamethasone (TAD) regimens for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). Conclusion The NMA demonstrated that the VTD, VTDC, and TAD regimens are most beneficial in terms of ORR, OS, and PFS for transplant-eligible patients with NDMM, respectively. PMID:28744159

CNS response to osimertinib in patients with T790M-positive advanced NSCLC: pooled data from two phase II trials.

PubMed

Goss, G; Tsai, C-M; Shepherd, F A; Ahn, M-J; Bazhenova, L; Crinò, L; de Marinis, F; Felip, E; Morabito, A; Hodge, R; Cantarini, M; Johnson, M; Mitsudomi, T; Jänne, P A; Yang, J C-H

2018-03-01

Central nervous system (CNS) metastases are common in patients with non-small-cell lung cancer (NSCLC). Osimertinib has shown systemic efficacy in patients with CNS metastases, and early clinical evidence shows efficacy in the CNS. To evaluate osimertinib activity further, we present a pre-specified subgroup analysis of CNS response using pooled data from two phase II studies: AURA extension (NCT01802632) and AURA2 (NCT02094261). Patients with T790M-positive advanced NSCLC, who had progressed following prior epidermal growth factor receptor-tyrosine kinase inhibitor treatment, received osimertinib 80 mg od (n = 411). Patients with stable, asymptomatic CNS metastases were eligible for enrolment; prior CNS treatment was allowed. Patients with ≥1 measurable CNS lesion (per RECIST 1.1) on baseline brain scan by blinded independent central neuroradiology review (BICR) were included in the evaluable for CNS response set (cEFR). The primary outcome for this CNS analysis was CNS objective response rate (ORR) by BICR; secondary outcomes included CNS duration of response, disease control rate (DCR) and progression-free survival (PFS). Of 128 patients with CNS metastases on baseline brain scans, 50 were included in the cEFR. Confirmed CNS ORR and DCR were 54% [27/50; 95% confidence interval (CI) 39-68] and 92% (46/50; 95% CI 81-98), respectively. CNS response was observed regardless of prior radiotherapy to the brain. Median CNS duration of response (22% maturity) was not reached (range, 1-15 months); at 9 months, 75% (95% CI 53-88) of patients were estimated to remain in response. Median follow-up for CNS PFS was 11 months; median CNS PFS was not reached (95% CI, 7, not calculable). The safety profile observed in the cEFR was consistent with the overall patient population. Osimertinib demonstrated clinically meaningful efficacy against CNS metastases, with a high DCR, encouraging ORR, and safety profile consistent with that reported previously. NCT01802632; NCT02094261.

Outcomes in 370 patients with mantle cell lymphoma treated with ibrutinib: a pooled analysis from three open-label studies.

PubMed

Rule, Simon; Dreyling, Martin; Goy, Andre; Hess, Georg; Auer, Rebecca; Kahl, Brad; Cavazos, Nora; Liu, Black; Yang, Shiyi; Clow, Fong; Goldberg, Jenna D; Beaupre, Darrin; Vermeulen, Jessica; Wildgust, Mark; Wang, Michael

2017-11-01

Ibrutinib is highly active in treating mantle cell lymphoma (MCL), an aggressive B-cell lymphoma. We pooled data from three ibrutinib studies to explore the impact of baseline patient characteristics on treatment response. Patients with relapsed/refractory MCL (n = 370) treated with ibrutinib had an objective response rate (ORR) of 66% (20% complete response; 46% partial response); median duration of response (DOR), progression-free survival (PFS) and overall survival (OS) were 18·6, 12·8 and 25·0 months, respectively. Univariate analyses showed patients with one versus >one prior line of therapy had longer OS. Multivariate analyses identified that one prior line of therapy affected PFS; Eastern Cooperative Oncology Group (ECOG) performance status, simplified MCL international prognostic index (sMIPI) score, bulky disease, and blastoid histology affected OS and PFS. Patients with blastoid versus non-blastoid histology had similar time to best response, but lower ORR, DOR, PFS and OS. OS and PFS were longer in patients with better sMIPI, patients with ECOG performance status 0-1, non-bulky disease and non-blastoid histology. Additionally, the proportion of patients with poor prognostic factors increased with increasing lines of therapy. Together, results suggest that patient outcomes following treatment failure with ibrutinib are related to the natural biological evolution of the disease. © 2017 John Wiley & Sons Ltd.

Testing Orr's document delivery test on biomedical journals in South Africa.

PubMed Central

Steynberg, S; Rossouw, S F

1995-01-01

This paper describes the use of a document delivery test (DDT) to measure the availability of biomedical research journals in South African health sciences libraries. The methodology employed was developed twenty years ago by a team of researchers from the Institute for the Advancement of Medical Communication under the direction of R. H. Orr. The testing of the methodology was in itself an objective of the present research. A citation pool consisting of 307 items was constructed from references to journal articles in papers published in 1989 by South African biomedical researchers. The availability of each article was determined at each of seven medical library sites; the performance was measured and presented as an arithmetical value or document delivery capability index (CI). The results of the tests show a high level of availability, ranging from CI = 81.68 to CI = 92.97 for the journals sampled. The DDT methodology was found to be practical, applicable to such studies, and flexible. Its use is recommended for similar studies. Images PMID:7703944

[Clinical observation of icotinib hydrochloride for patients with advanced non-small cell lung cancer].

PubMed

Li, Xi; Yang, Xin-jie; Sun, Yi-fen; Qin, Na; Lü, Jia-lin; Wu, Yu-hua; Zhang, Hui; Zhang, Quan; Zhang, Shu-cai

2012-08-01

To explore the efficacy and side effects of icotinib hydrochloride in the treatment of patients with advanced non-small cell lung cancer (NSCLC). The efficacy and side effects of icotinib hydrochloride in treatment of 59 cases with stage IV NSCIC and followed-up from March 2009 to January 2012 were retrospectively analyzed. Twenty seven patients (45.8%) showed partial response (PR), 17 patients (28.8%) achieved SD, and 15 (25.4%) had progressive disease. The objective response rate (ORR) was 45.8% (27/59), and disease control rate (DCR) was 74.6% (44/59). Among the 23 patients with EGFR mutation, ORR was 73.9% (17/23), and DCR was 95.7% (22/23). Thirty six patients (61.0%) achieved remission of symptoms to varying degrees. The main symptoms relieved were cough, asthmatic suffocating, pain and hoarseness. The major adverse events were mild skin rash (35.6%) and diarrhea (15.3%). Others were dry skin, nausea and stomach problems. The efficacy of icotinib hydrochloride were related to the ECOG performance status, smoking history, EGFR mutation and rash significantly (P < 0.05). Monotherapy with icotinib hydrochloride is effective and tolerable for patients with advanced NSCLC, especially with EGFR mutation.

Double-Blind, Randomized Trial of Docetaxel Plus Vandetanib Versus Docetaxel Plus Placebo in Platinum-Pretreated Metastatic Urothelial Cancer

PubMed Central

Choueiri, Toni K.; Ross, Robert W.; Jacobus, Susanna; Vaishampayan, Ulka; Yu, Evan Y.; Quinn, David I.; Hahn, Noah M.; Hutson, Thomas E.; Sonpavde, Guru; Morrissey, Stephanie C.; Buckle, Geoffrey C.; Kim, William Y.; Petrylak, Daniel P.; Ryan, Christopher W.; Eisenberger, Mario A.; Mortazavi, Amir; Bubley, Glenn J.; Taplin, Mary-Ellen; Rosenberg, Jonathan E.; Kantoff, Philip W.

2012-01-01

Purpose Vandetanib is an oral once-daily tyrosine kinase inhibitor with activity against vascular endothelial growth factor receptor 2 and epidermal growth factor receptor. Vandetanib in combination with docetaxel was assessed in patients with advanced urothelial cancer (UC) who progressed on prior platinum-based chemotherapy. Patients and Methods The primary objective was to determine whether vandetanib 100 mg plus docetaxel 75 mg/m2 intravenously every 21 days prolonged progression-free survival (PFS) versus placebo plus docetaxel. The study was designed to detect a 60% improvement in median PFS with 80% power and one-sided α at 5%. Patients receiving docetaxel plus placebo had the option to cross over to single-agent vandetanib at progression. Overall survival (OS), overall response rate (ORR), and safety were secondary objectives. Results In all, 142 patients were randomly assigned and received at least one dose of therapy. Median PFS was 2.56 months for the docetaxel plus vandetanib arm versus 1.58 months for the docetaxel plus placebo arm, and the hazard ratio for PFS was 1.02 (95% CI, 0.69 to 1.49; P = .9). ORR and OS were not different between both arms. Grade 3 or higher toxicities were more commonly seen in the docetaxel plus vandetanib arm and included rash/photosensitivity (11% v 0%) and diarrhea (7% v 0%). Among 37 patients who crossed over to single-agent vandetanib, ORR was 3% and OS was 5.2 months. Conclusion In this platinum-pretreated population of advanced UC, the addition of vandetanib to docetaxel did not result in a significant improvement in PFS, ORR, or OS. The toxicity of vandetanib plus docetaxel was greater than that for vendetanib plus placebo. Single-agent vandetanib activity was minimal. PMID:22184381

Examining the Relationship Between Word Reading Efficiency and Oral Reading Rate in Predicting Comprehension Among Different Types of Readers

PubMed Central

Eason, Sarah H.; Sabatini, John; Goldberg, Lindsay; Bruce, Kelly; Cutting, Laurie E.

2013-01-01

To further explore contextual reading rate, an important aspect of reading fluency, we examined the relationship between word reading efficiency (WRE) and contextual oral reading rate (ORR), the degree to which they overlap across different comprehension measures, whether oral language (semantics and syntax) predicts ORR beyond contributions of word-level skills, and whether the WRE–ORR relationship varies based on different reader profiles. Assessing reading and language of average readers, poor decoders, and poor comprehenders, ages 10 to 14, ORR was the strongest predictor of comprehension across various formats; WRE contributed no unique variance after taking ORR into account. Findings indicated that semantics, not syntax, contributed to ORR. Poor comprehenders performed below average on measures of ORR, despite average WRE, expanding previous findings suggesting specific weaknesses in ORR for this group. Together, findings suggest that ORR draws upon skills beyond those captured by WRE and suggests a role for oral language (semantics) in ORR. PMID:23667307

[Clinical Observation of Icotinib Hydrochloride for Advanced Non-small Cell Lung Cancer Patients with EGFR Status Identified].

PubMed

Li, Xi; Qin, Na; Wang, Jinghui; Yang, Xinjie; Zhang, Xinyong; Lv, Jialin; Wu, Yuhua; Zhang, Hui; Nong, Jingying; Zhang, Quan; Zhang, Shucai

2015-12-01

Icotinib is the first self-developed small molecular drug in China for targeted therapy of lung cancer. Compared to the other two commercially available epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, gefitinib and erlotinib, icotinib is similar to them in chemical structure, mechanism of activity and therapeutic effects. To explore the efficacy and side effects of icotinib hydrochloride in the treatment of the advanced non-small cell lung cancer (NSCLC) patients with EGFR mutation and wild-type. Patients with advanced NSCLC who were treated with icotinib hydrochloride in Beijing Chest Hospital were retrospective analyzed from March 2009 to December 2014. The clinical data of 124 patients (99 with EGFR mutation and 25 with wild type) with advanced NSCLC were enrolled in this study. The patients' overall objective response rate (ORR) was 51.6 % and the disease control rate (DCR) was 79.8%; The patients with EGFR mutation, ORR was 63.6%, DCR was 93.9%. The ORR was 4.0% and the DCR was 24.0% in the wild-type patients. Median progression-free survival (PFS) with icotinib treatment in EGFR mutation patients was 10.5 months and 1.0 month in wild-type patients. The major adverse events were mild skin rash (30.6%) and diarrhea (16.1%). Monotherapy with icotinib hydrochloride is effective and tolerable for the advanced NSCLC EGFR mutation patients.


LTRs of endogenous retroviruses as a source of Tbx6 binding sites

NASA Astrophysics Data System (ADS)

Yasuhiko, Yukuto; Hirabayashi, Yoko; Ono, Ryuichi

2017-06-01

Retrotransposons are abundant in mammalian genomes and can modulate the gene expression of surrounding genes by disrupting endogenous binding sites for transcription factors (TFs) or providing novel TFs binding sites within retrotransposon sequences. Here, we show that a (C/T)CACACCT sequence motif in ORR1A, ORR1B, ORR1C and ORR1D, Long Terminal Repeats (LTRs) of MaLR endogenous retrovirus (ERV), is the direct target of Tbx6, an evolutionary conserved family of T-box transcription factors. Moreover, by comparing gene expression between control mice (Tbx6 +/-) and Tbx6-deficient mice (Tbx6 -/-), we demonstrate that at least four genes, Twist2, Pitx2, Oscp1, and Nfxl1, are down-regulated with Tbx6 deficiency. These results suggest that ORR1A, ORR1B, ORR1C and ORR1D may contribute to the evolution of mammalian embryogenesis.

LTRs of Endogenous Retroviruses as a Source of Tbx6 Binding Sites

PubMed Central

Yasuhiko, Yukuto; Hirabayashi, Yoko; Ono, Ryuichi

2017-01-01

Retrotransposons are abundant in mammalian genomes and can modulate the gene expression of surrounding genes by disrupting endogenous binding sites for transcription factors (TFs) or providing novel TFs binding sites within retrotransposon sequences. Here, we show that a (C/T)CACACCT sequence motif in ORR1A, ORR1B, ORR1C, and ORR1D, Long Terminal Repeats (LTRs) of MaLR endogenous retrovirus (ERV), is the direct target of Tbx6, an evolutionary conserved family of T-box TFs. Moreover, by comparing gene expression between control mice (Tbx6 +/−) and Tbx6-deficient mice (Tbx6 −/−), we demonstrate that at least four genes, Twist2, Pitx2, Oscp1, and Nfxl1, are down-regulated with Tbx6 deficiency. These results suggest that ORR1A, ORR1B, ORR1C and ORR1D may contribute to the evolution of mammalian embryogenesis. PMID:28664156

LTRs of Endogenous Retroviruses as a Source of Tbx6 Binding Sites.

PubMed

Yasuhiko, Yukuto; Hirabayashi, Yoko; Ono, Ryuichi

2017-01-01

Retrotransposons are abundant in mammalian genomes and can modulate the gene expression of surrounding genes by disrupting endogenous binding sites for transcription factors (TFs) or providing novel TFs binding sites within retrotransposon sequences. Here, we show that a (C/T)CACACCT sequence motif in ORR1A, ORR1B, ORR1C, and ORR1D, Long Terminal Repeats (LTRs) of MaLR endogenous retrovirus (ERV), is the direct target of Tbx6, an evolutionary conserved family of T-box TFs. Moreover, by comparing gene expression between control mice (Tbx6 +/-) and Tbx6-deficient mice (Tbx6 -/-), we demonstrate that at least four genes, Twist2, Pitx2, Oscp1 , and Nfxl1 , are down-regulated with Tbx6 deficiency. These results suggest that ORR1A, ORR1B, ORR1C and ORR1D may contribute to the evolution of mammalian embryogenesis.

BIM Gene Polymorphism Lowers the Efficacy of EGFR-TKIs in Advanced Nonsmall Cell Lung Cancer With Sensitive EGFR Mutations: A Systematic Review and Meta-Analysis.

PubMed

Huang, Wu Feng; Liu, Ai Hua; Zhao, Hai Jin; Dong, Hang Ming; Liu, Lai Yu; Cai, Shao Xi

2015-08-01

The strong association between bcl-2-like 11 (BIM) triggered apoptosis and the presence of epidermal growth factor receptor (EGFR) mutations has been proven in nonsmall cell lung cancer (NSCLC). However, the relationship between EGFR-tyrosine kinase inhibitor's (TKI's) efficacy and BIM polymorphism in NSCLC EGFR is still unclear.Electronic databases were searched for eligible literatures. Data on objective response rates (ORRs), disease control rates (DCRs), and progression-free survival (PFS) stratified by BIM polymorphism status were extracted and synthesized based on random-effect model. Subgroup and sensitivity analyses were conducted.A total of 6 studies that involved a total of 773 EGFR mutant advanced NSCLC patients after EGFR-TKI treatment were included. In overall, non-BIM polymorphism patients were associated with significant prolonged PFS (hazard ratio 0.63, 0.47-0.83, P = 0.001) compared to patients with BIM polymorphism. However, only marginal improvements without statistical significance in ORR (odds ratio [OR] 1.71, 0.91-3.24, P = 0.097) and DCR (OR 1.56, 0.85-2.89, P = 0.153) were observed. Subgroup analyses showed that the benefits of PFS in non-BIM polymorphism group were predominantly presented in pooled results of studies involving chemotherapy-naive and the others, and retrospective studies. Additionally, we failed to observe any significant benefit from patients without BIM polymorphism in every subgroup for ORR and DCR.For advanced NSCLC EGFR mutant patients, non-BIM polymorphism ones are associated with longer PFS than those with BIM polymorphism after EGFR-TKIs treatment. BIM polymorphism status should be considered an essential factor in studies regarding EGFR-targeted agents toward EGFR mutant patients.

FDA Approval: Alectinib for the Treatment of Metastatic, ALK-Positive Non-Small Cell Lung Cancer Following Crizotinib.

PubMed

Larkins, Erin; Blumenthal, Gideon M; Chen, Huanyu; He, Kun; Agarwal, Rajiv; Gieser, Gerlie; Stephens, Olen; Zahalka, Eias; Ringgold, Kimberly; Helms, Whitney; Shord, Stacy; Yu, Jingyu; Zhao, Hong; Davis, Gina; McKee, Amy E; Keegan, Patricia; Pazdur, Richard

2016-11-01

On December 11, 2015, the FDA granted accelerated approval to alectinib (Alecensa; Genentech) for the treatment of patients with anaplastic lymphoma receptor tyrosine kinase (ALK)-positive, metastatic non-small cell lung cancer (NSCLC) who have progressed on or are intolerant to crizotinib. This approval was based on two single-arm trials including 225 patients treated with alectinib 600 mg orally twice daily. The objective response rates (ORR) by an independent review committee in these studies were 38% [95% confidence interval (CI), 28-49] and 44% (95% CI, 36-53); the median durations of response (DOR) were 7.5 months and 11.2 months. In a pooled analysis of 51 patients with measurable disease in the central nervous system (CNS) at baseline, the CNS ORR was 61% (95% CI, 46-74); the CNS DOR was 9.1 months. The primary safety analysis population included 253 patients. The most common adverse reactions were fatigue (41%), constipation (34%), edema (30%), and myalgia (29%). The most common laboratory abnormalities were anemia (56%), increased aspartate aminotransferase (51%), increased alkaline phosphatase (47%), increased creatine phosphokinase (43%), hyperbilirubinemia (39%), hyperglycemia (36%), increased alanine aminotransferase (34%), and hypocalcemia (32%). Dose reductions due to adverse reactions occurred in 12% of patients, whereas 27% of patients had alectinib dosing interrupted for adverse reactions. Permanent discontinuation of alectinib due to adverse reactions occurred in only 6% of patients. With the clinically meaningful ORR and DOR as well as the safety profile observed in these trials, alectinib was determined to have a favorable benefit-risk profile for the treatment of the indicated population. Clin Cancer Res; 22(21); 5171-6. ©2016 AACR. ©2016 American Association for Cancer Research.

Mink reproductive and physiological response to diets supplemented with PCB and mercury contaminated fish collected on the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halbrook, R.; Aulerich, R.; Bursian, S.

1995-12-31

Plant operations and waste disposal at the Department of Energy Oak Ridge Reservation (ORR) have resulted in increased concentrations of PCBs and mercury (Hg) in fish inhabiting streams located on the reservation. As a component of environmental restoration investigation, fish were collected from streams on the reservation, analyzed for tissue concentrations of PCBs and Hg, and fed to ranch mink 3 months prior to and during the breeding season. As reference, fish also were collected from the Clinch River (CR) above the ORR and from the ocean (O), and fed to mink following similar procedures. Five prepared diets containing eithermore » 75% O, 75% CR, 25% ORR + 50% O, 50% ORR + 25% O, or 75% ORR fish and 25% standard mink diet were fed to 8 female and 2 male mink, each, following normal mink farm practices. PCB (Aroclor 1260 and CB congeners) and Hg concentrations were greatest in fish collected from the ORR and diets containing ORR fish exhibited a progressive increase in PCBs and Hg concentration with increased percentage of ORR fish. Female mink fed diets containing 75% ORR fish had decreased litter size and decreased mean whole body weights, Mean weight of male offspring of females fed 75% ORR fish also were decreased. Do to the contaminated environment, other aquatic prey of mink probably have elevated contaminant burdens that would contribute to effects in mink. Adverse reproductive and health effects in mink living on the ORR are speculative at this time.« less

Report on the oversight assessment of the operational readiness review of the Replacement Tritium Facility at Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, B.T.

1993-03-01

This report presents the results of an oversight assessment (OA) conducted by the US Department of Energy's (DOE) Office of Environment, Safety and Health (EH) of operational readiness review (ORR) activities for the Replacement Tritium Facility (RTF) located at Savannah River Site (SRS). The EH OA of this facility took place concurrently with an ORR conducted by the DOE Office of Defense Programs (DP). The DP ORR was conducted from January 19 through February 5, 1993. The EH OA was performed in accordance with the protocol and procedures specified in EH Program for Oversight Assessment of Operational Readiness Evaluations formore » Startups and Restarts,'' dated September 15, 1992. The EH OA Team evaluated the DP ORR to determine whether it was thorough and demonstrated sufficient inquisitiveness to verify that the implementation of programs and procedures adequately ensures the protection of worker safety and health. The EH OA Team performed its evaluation of the DP ORR in the following technical areas: occupational safety, industrial hygiene, and respiratory protection; fire protection; and chemical safety. In the areas of fire protection and chemical safety, the EH OA Team conducted independent vertical-slice reviews to confirm DP ORR results. Within each technical area, the EH OA Team reviewed the DP ORR Plan, including the Criteria Review and Approach Documents (CRADs); the qualifications of individual DP ORR team members; the performance of planned DP ORR activities; and the results of the DP ORR.« less

Report on the oversight assessment of the operational readiness review of the Replacement Tritium Facility at Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, B.T.

1993-03-01

This report presents the results of an oversight assessment (OA) conducted by the US Department of Energy`s (DOE) Office of Environment, Safety and Health (EH) of operational readiness review (ORR) activities for the Replacement Tritium Facility (RTF) located at Savannah River Site (SRS). The EH OA of this facility took place concurrently with an ORR conducted by the DOE Office of Defense Programs (DP). The DP ORR was conducted from January 19 through February 5, 1993. The EH OA was performed in accordance with the protocol and procedures specified in ``EH Program for Oversight Assessment of Operational Readiness Evaluations formore » Startups and Restarts,`` dated September 15, 1992. The EH OA Team evaluated the DP ORR to determine whether it was thorough and demonstrated sufficient inquisitiveness to verify that the implementation of programs and procedures adequately ensures the protection of worker safety and health. The EH OA Team performed its evaluation of the DP ORR in the following technical areas: occupational safety, industrial hygiene, and respiratory protection; fire protection; and chemical safety. In the areas of fire protection and chemical safety, the EH OA Team conducted independent vertical-slice reviews to confirm DP ORR results. Within each technical area, the EH OA Team reviewed the DP ORR Plan, including the Criteria Review and Approach Documents (CRADs); the qualifications of individual DP ORR team members; the performance of planned DP ORR activities; and the results of the DP ORR.« less

Operational Readiness Review Final Report for K Basin Fuel Transfer System

DOE Office of Scientific and Technical Information (OSTI.GOV)

DAVIES, T.H.

2002-10-01

An Operational Readiness Review (ORR) was conducted by the U.S. Department of Energy (DOE), Richland Operations Office (RL) to verify that an adequate state of readiness had been achieved for startup of the K Basin Fuel Transfer System (FTS). The DOE ORR was conducted during the period November 6-18, 2002. The DOE ORR team concluded that the K Basin Fuel Transfer System is ready to start operations, subject to completion and verification of identified pre-start findings. The ORR was conducted in accordance with the Spent Nuclear Fuel (SNF) K Basin Fuel Transfer System (FTS) Operational Readiness Review (ORR) Plan ofmore » Action and the Operational Readiness Review Implementation Plan for K Basin Fuel Transfer System. Review activities consisted of staff interviews, procedure and document reviews, and observations of normal facility operations, operational upset conditions, and an emergency drill. The DOE ORR Team also reviewed and assessed the adequacy of the contractor ORR3 and the RL line management review. The team concurred with the findings and observations identified in these two reports. The DOE ORR for the FTS evaluated the contractor under single-shift operations. Of concern to the ORR Team was that SNF Project management intended to change from a single-shift FTS operation to a two-shift operation shortly after the completion of the DOE ORR. The ORR team did not assess two-shift FTS operations and the ability of the contractor to conduct a smooth transition from shift to shift. However, the DOE ORR team did observe an operational upset drill that was conducted during day shift and carried over into swing shift; during this drill, swing shift was staffed with fewer personnel as would be expected for two-shift operations. The facility was able to adequately respond to the event with the reduced level of staff. The ORR Team was also able to observe a Shift Manager turnover meeting when one shift manager had to be relieved during the middle of the day. The ORR Team did not have the opportunity to observe a shift turnover from one crew to another. The ORR Team has evaluated the risk of not observing this activity and considers the risk to be minimal based on the fact that operating staff are very familiar with the FTS equipment and its procedures, and because existing Conduct of Operations processes and procedures are adequate and implemented. Because the ORR Team has not observed two-shift FTS operations, we recommend that additional RL oversight be provided at the start of two-shift FTS operations to evaluate the adequacy of crew turnovers.« less

Numerical simulation of heat transfer and fluid flow during double-sided laser beam welding of T-joints for aluminum aircraft fuselage panels

NASA Astrophysics Data System (ADS)

Yang, Zhibin; Tao, Wang; Li, Liqun; Chen, Yanbin; Shi, Chunyuan

2017-06-01

In comparison with conventional laser beam welding, double-sided laser beam welding has two laser heat sources simultaneously and symmetrically loaded from both sides makes it to be a more complicated coupled heat transport and fluid flow process. In this work, in order to understand the heat transfer and fluid flow, a three-dimensional model was developed and validated with the experimental results. The temperature field, fluid flow field, and keyhole characteristic were calculated using the developed model by FLUENT software. Calculated results indicated that the temperature and fluid flow fields were bilateral symmetry along the stringer center, and the molten pool maximum length was located near the keyhole intersection position. The skin side had higher temperature and faster cooling speed. Several characteristic flow patterns in the weld pool cross section, including the vortexes flows near the keyhole opening position, the convection flows above the keyhole intersection location, the regularity downward flows at the molten pool bottom. And in the lengthwise section, a distinct vortex flow below the keyhole, and the liquid metal behind the keyhole first flowed to near the molten pool maximum length location and then to the molten pool surface. Perpendicular to and along welding direction the keyhole liquid metal flowed to the weld molten pool surface and around the keyhole, respectively. The special temperature fields and fluid flow patterns were closely related to the effects of the double sides' laser energy coupling and enhancement. The calculated weld pool geometry basically in good agreement with the experimental results indicated that the developed model was validity and reasonable.

Highly methanol-tolerant platinum electrocatalyst derived from poly(vinylpoyrrolidone) coating

NASA Astrophysics Data System (ADS)

Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Yang, Ming

2017-02-01

The design and fabrication of a methanol-tolerant electrocatalyst is still one of the most important issues in direct methanol fuel cells (DMFCs). Here, we focus on the design of a cathodic electrocatalyst in DMFCs and describe a new methanol-tolerant electrocatalyst fabricated from poly(vinylpyrrolidone) (PVP) coating on platinum nanoparticles assisted by hydrogen bonding between PVP and polybenzimidazole (PBI). The PVP layer has a negligible effect on the oxygen reduction reaction (ORR) activity, while the methanol oxidation reaction is retarded by the PVP layer. The PVP-coated electrocatalyst shows higher ORR activity under various methanol concentrations in the electrolyte, suggesting that the PVP-coated electrocatalyst has a higher methanol tolerance. Also, the PVP-coated electrocatalyst loses only 14% of the electrochemical surface area after 5000 potential cycles from 0.6-1.0 V versus the reversible hydrogen electrode, indicating better Pt stability than non-coated (27%) and commercial (38%) electrocatalysts due to the unique sandwich structure formed by the PVP and PBI. The power density of the PVP-coated electrocatalyst is four to five times higher compared to non-coated and commercial electrocatalysts with 12 M methanol feeding to the anode side, respectively. PVP coating is important for the enhancement of Pt stability and methanol tolerance. This study offers a new method for preparing a low-cost and high-methanol-tolerant Pt electrocatalyst, and useful information for real DMFC application to eliminate the methanol crossover problem in the cathode side.

Control of reactor coolant flow path during reactor decay heat removal

DOEpatents

Hunsbedt, Anstein N.

1988-01-01

An improved reactor vessel auxiliary cooling system for a sodium cooled nuclear reactor is disclosed. The sodium cooled nuclear reactor is of the type having a reactor vessel liner separating the reactor hot pool on the upstream side of an intermediate heat exchanger and the reactor cold pool on the downstream side of the intermediate heat exchanger. The improvement includes a flow path across the reactor vessel liner flow gap which dissipates core heat across the reactor vessel and containment vessel responsive to a casualty including the loss of normal heat removal paths and associated shutdown of the main coolant liquid sodium pumps. In normal operation, the reactor vessel cold pool is inlet to the suction side of coolant liquid sodium pumps, these pumps being of the electromagnetic variety. The pumps discharge through the core into the reactor hot pool and then through an intermediate heat exchanger where the heat generated in the reactor core is discharged. Upon outlet from the heat exchanger, the sodium is returned to the reactor cold pool. The improvement includes placing a jet pump across the reactor vessel liner flow gap, pumping a small flow of liquid sodium from the lower pressure cold pool into the hot pool. The jet pump has a small high pressure driving stream diverted from the high pressure side of the reactor pumps. During normal operation, the jet pumps supplement the normal reactor pressure differential from the lower pressure cold pool to the hot pool. Upon the occurrence of a casualty involving loss of coolant pump pressure, and immediate cooling circuit is established by the back flow of sodium through the jet pumps from the reactor vessel hot pool to the reactor vessel cold pool. The cooling circuit includes flow into the reactor vessel liner flow gap immediate the reactor vessel wall and containment vessel where optimum and immediate discharge of residual reactor heat occurs.

Oxygen Reduction on Gold Nanocrystal Surfaces in Alkaline Electrolyte: Evidence for Surface Proton Transfer Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yu; Lu, Fang; Liu, Shizhong

Four-electron oxygen reduction reaction (4e-ORR) pathway, as a key high-performance reaction pathway in energy conversion, has been sought after in numerous investigations on metal surfaces over the last decades. Although the surfaces of the most noble metals, including platinum and palladium, demonstrate the fullpotential- range 4e-ORR, this is not the case, for gold (Au) surfaces. The 4e-ORR is only operative on Au surfaces with {100} subfacets, e.g. Au(100), in alkaline solution, however restricted to a certain potential region at low overpotentials, while reverting to a 2e-ORR at high overpotentials. This ORR on Au(100) has been a long-standing puzzle of electrocatalysis.more » Hereby we review the ORR studies on Au, along with the studies of water effects on Au catalysts, and present our electrochemical results with monofacet Au nanocrystals. Finally, combining with theoretical calculations we demonstrate that surface proton transfer from co-adsorbed water plays the key role in determining the ORR mechanism on Au surfaces in base.« less

Oxygen Reduction on Gold Nanocrystal Surfaces in Alkaline Electrolyte: Evidence for Surface Proton Transfer Effects

DOE PAGES

Zhang, Yu; Lu, Fang; Liu, Shizhong; ...

2018-04-01

Four-electron oxygen reduction reaction (4e-ORR) pathway, as a key high-performance reaction pathway in energy conversion, has been sought after in numerous investigations on metal surfaces over the last decades. Although the surfaces of the most noble metals, including platinum and palladium, demonstrate the fullpotential- range 4e-ORR, this is not the case, for gold (Au) surfaces. The 4e-ORR is only operative on Au surfaces with {100} subfacets, e.g. Au(100), in alkaline solution, however restricted to a certain potential region at low overpotentials, while reverting to a 2e-ORR at high overpotentials. This ORR on Au(100) has been a long-standing puzzle of electrocatalysis.more » Hereby we review the ORR studies on Au, along with the studies of water effects on Au catalysts, and present our electrochemical results with monofacet Au nanocrystals. Finally, combining with theoretical calculations we demonstrate that surface proton transfer from co-adsorbed water plays the key role in determining the ORR mechanism on Au surfaces in base.« less

Eco-engineered rock pools: a concrete solution to biodiversity loss and urban sprawl in the marine environment

NASA Astrophysics Data System (ADS)

Firth, Louise B.; Browne, Keith A.; Knights, Antony M.; Hawkins, Stephen J.; Nash, Róisín

2016-09-01

In coastal habitats artificial structures typically support lower biodiversity and can support greater numbers of non-native and opportunistic species than natural rocky reefs. Eco-engineering experiments are typically trialed to succeed; but arguably as much is learnt from failure than from success. Our goal was to trial a generic, cost effective, eco-engineering technique that could be incorporated into rock armouring anywhere in the world. Artificial rock pools were created from manipulated concrete between boulders on the exposed and sheltered sides of a causeway. Experimental treatments were installed in locations where they were expected to fail and compared to controls installed in locations in which they were expected to succeed. Control pools were created lower on the structure where they were immersed on every tidal cycle; experimental pools were created above mean high water spring tide which were only immersed on spring tides. We hypothesised that lower and exposed pools would support significantly higher taxon and functional diversity than upper and sheltered pools. The concrete pools survived the severe winter storms of 2013/14. After 12 months, non-destructive sampling revealed significantly higher mean taxon and functional richness in lower pools than upper pools on the exposed side only. After 24 months the sheltered pools had become inundated with sediments, thus failing to function as rock pools as intended. Destructive sampling on the exposed side revealed significantly higher mean functional richness in lower than upper pools. However, a surprisingly high number of taxa colonised the upper pools leading to no significant difference in mean taxon richness among shore heights. A high number of rare taxa in the lower pools led to total taxon richness being almost twice that of upper pools. These findings highlight that even when expected to fail concrete pools supported diverse assemblages, thus representing an affordable, replicable means of enhancing biodiversity on a variety of artificial structures.

Evaluation of oxygen reduction activity by the thin-film rotating disk electrode methodology: The effects of potentiodynamic parameters

DOE PAGES

Chen, Guangyu; Li, Meng; Kuttiyiel, Kurian A.; ...

2016-04-11

Here, an accurate and efficient assessment of activity is critical for the research and development of electrocatalysts for oxygen reduction reaction (ORR). Currently, the methodology combining the thin-film rotating disk electrode (TF-RDE) and potentiodynamic polarization is the most commonly used to pre-evaluate ORR activity, acquire kinetic data (i.e., kinetic current, Tafel slope, etc.), and gain understanding of the ORR mechanism. However, it is often neglected that appropriate potentiodynamic parameters have to be chosen to obtain reliable results. We first evaluate the potentiodynamic and potentiostatic polarization measurements with TF-RDE to examine the ORR activity of Pt nanoelectrocatalyst. Furthermore, our results demonstratemore » that besides depending on the nature of electrocatalyst, the apparent ORR kinetics also strongly depends on the associated potentiodynamic parameters, such as scan rate and scan region, which have a great effect on the coverage of adsorbed OH ad/O ad on Pt surface, thereby affecting the ORR activities of both nanosized and bulk Pt. However, the apparent Tafel slopes remained nearly the same, indicating that the ORR mechanism in all the measurements was not affected by different potentiodynamic parameters.« less

Size-Controlled Synthesis of Sub-10 nm PtNi3 Alloy Nanoparticles and their Unusual Volcano-Shaped Size Effect on ORR Electrocatalysis.

PubMed

Gan, Lin; Rudi, Stefan; Cui, Chunhua; Heggen, Marc; Strasser, Peter

2016-06-01

Dealloyed Pt bimetallic core-shell catalysts derived from low-Pt bimetallic alloy nanoparticles (e.g, PtNi3 ) have recently shown unprecedented activity and stability on the cathodic oxygen reduction reaction (ORR) under realistic fuel cell conditions and become today's catalyst of choice for commercialization of automobile fuel cells. A critical step toward this breakthrough is to control their particle size below a critical value (≈10 nm) to suppress nanoporosity formation and hence reduce significant base metal (e.g., Ni) leaching under the corrosive ORR condition. Fine size control of the sub-10 nm PtNi3 nanoparticles and understanding their size dependent ORR electrocatalysis are crucial to further improve their ORR activity and stability yet still remain unexplored. A robust synthetic approach is presented here for size-controlled PtNi3 nanoparticles between 3 and 10 nm while keeping a constant particle composition and their size-selected growth mechanism is studied comprehensively. This enables us to address their size-dependent ORR activities and stabilities for the first time. Contrary to the previously established monotonic increase of ORR specific activity and stability with increasing particle size on Pt and Pt-rich bimetallic nanoparticles, the Pt-poor PtNi3 nanoparticles exhibit an unusual "volcano-shaped" size dependence, showing the highest ORR activity and stability at the particle sizes between 6 and 8 nm due to their highest Ni retention during long-term catalyst aging. The results of this study provide important practical guidelines for the size selection of the low Pt bimetallic ORR electrocatalysts with further improved durably high activity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Report of the oversight assessment of the operational readiness review of the Savannah River Site Defense Waste Processing Facility Cold Chemical Runs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, B.

1993-03-01

This report presents the results of an oversight assessment (OA) conducted by the US Department of Energy's (DOE) Office of Environment, Safety and Health (EH) of the operational readiness review (ORR) activities for the Cold Chemical Runs (CCRs) at the Defense Waste Processing Facility (DWPF) located at Savannah River Site (SRS). The EH OA of this facility took place concurrently with an ORR performed by the DOE Office of Environmental Restoration and Waste Management (EM). The EM ORR was conducted from September 28, 1992, through October 9, 1992, although portions of the EM ORR were extended beyond this period. Themore » EH OA evaluated the comprehensiveness and effectiveness of the EM ORR. The EH OA was designed to ascertain whether the EM ORR was thorough and demonstrated sufficient inquisitiveness to verify that the implementation of programs and procedures is adequate to assure the protection of worker safety and health. The EH OA was carried out in accordance with the protocol and procedures of the EH Program for Oversight Assessment of Operational Readiness Evaluations for Startups and Restarts,'' dated September 15, 1992. Based on its OA and verification of the resolution of EH OA findings, the EH OA Team believes that the startup of the CCRs may be safely begun, pending satisfactory completion and verification of the prestart findings identified by the EM ORR. The EH OA was based primarily on an evaluation of the comprehensiveness and effectiveness of the EM ORR and addressed the following areas: industrial safety, industrial hygiene, and respiratory protection; fire protection; and chemical safety. The EH OA conducted independent vertical-slice'' reviews to confirm EM ORR results in the areas of confined-space entry, respiratory protection, fire protection, and chemical safety.« less

Genetic analysis of adult plant, quantitative resistance to stripe rust in wheat cultivar 'Stephens' in multi-environment trials.

PubMed

Dolores Vazquez, M; James Peterson, C; Riera-Lizarazu, Oscar; Chen, Xianming; Heesacker, Adam; Ammar, Karim; Crossa, Jose; Mundt, Christopher C

2012-01-01

The wheat (Triticum aestivum L.) cultivar 'Stephens' has been grown commercially in the USA Pacific Northwest for 30 years. The durable resistance of 'Stephens' to stripe rust (Puccinia striiformis f. sp. tritici) was believed to be due to a combination of seedling and adult plant resistance genes. Multilocation field trials, diversity array technology (DArT), and simple sequence repeat (SSR) markers were used to identify quantitative trait loci (QTL) for resistance. Recombinant inbred lines were assessed for stripe rust response in eight locations/years, five in 2008 and three in 2009. The data from Mt. Vernon, WA, differed from all other environments, and composite interval mapping (CIM) identified three QTL, QYrst.orr-1AL, QYrst.orr-4BS, and QYrpl.orr-6AL, which accounted for 12, 11, and 6% of the phenotypic variance, respectively. CIM across the remaining six environments identified four main QTL. Two QTL, QYrst.orr-2BS.2 and QYrst.orr-7AS, were detected in five of six environments and explained 11 and 15% of the phenotypic variance, respectively. Two other QTL, QYrst.orr-2AS and QYrpl.orr-4BL, were detected across four and three of six environments, and explained 19 and 9% of the phenotypic variance, respectively. The susceptible parent 'Platte' contributed QYrpl.orr-4BL and QYrpl.orr-6AL, with the remaining QTL originating from 'Stephens'. For each environment, additional minor QTL were detected, each accounting for 6-10% of the phenotypic variance. Different QTL with moderate effects were identified in both 'Stephens' and 'Platte'. Significant QTL × environment interactions were evident, suggesting that specificity to plant stage, pathogen genotype, and/or temperature was important.

Boron doped graphene wrapped silver nanowires as an efficient electrocatalyst for molecular oxygen reduction

NASA Astrophysics Data System (ADS)

Nair, Anju K.; Thazhe Veettil, Vineesh; Kalarikkal, Nandakumar; Thomas, Sabu; Kala, M. S.; Sahajwalla, Veena; Joshi, Rakesh K.; Alwarappan, Subbiah

2016-12-01

Metal nanowires exhibit unusually high catalytic activity towards oxygen reduction reaction (ORR) due to their inherent electronic structures. However, controllable synthesis of stable nanowires still remains as a daunting challenge. Herein, we report the in situ synthesis of silver nanowires (AgNWs) over boron doped graphene sheets (BG) and demonstrated its efficient electrocatalytic activity towards ORR for the first time. The electrocatalytic ORR efficacy of BG-AgNW is studied using various voltammetric techniques. The BG wrapped AgNWs shows excellent ORR activity, with very high onset potential and current density and it followed four electron transfer mechanism with high methanol tolerance and stability towards ORR. The results are comparable to the commercially available 20% Pt/C in terms of performance.

Effect of first-line endocrine therapy in patients with hormone-sensitive advanced breast cancer: a network meta-analysis.

PubMed

Zhang, Tingting; Feng, Fubin; Zhao, Wenge; Tian, Jinhui; Yao, Yan; Zhou, Chao; Dong, Shengjie; Wang, Congcong; Zang, Chuanxin; Lv, Qingliang; Sun, Changgang

2018-01-01

Endocrine therapy is the cornerstone treatment for patients with hormone receptor-positive advanced breast cancer. We aimed to assess the effectiveness of various first-line endocrine monotherapies or combinations to determine the optimal sequence in a network meta-analysis. We searched PubMed, EMBASE, and the Cochrane Library for randomized controlled trials (RCTs) from inception up to November 21, 2017. We included only RCTs that assessed the effectiveness of the following treatments as a monotherapy or in combination as the first-line treatment: tamoxifen, anastrozole, letrozole, exemestane, fulvestrant, palbociclib, and ribociclib. The results were presented with pooled odds ratio or hazard ratio (HR), and 95% credible interval (CrI). The primary outcomes were objective response rate (ORR) and progression-free survival/time to progression. A total of 16 eligible articles (14 RCTs) involving 6,602 patients treated with 10 different first-line endocrine therapies were assessed in our network meta-analysis. Palbociclib plus letrozole was superior to anastrozole, letrozole, exemestane, fulvestrant 500 mg, and anastrozole plus fulvestrant (loading dose) (HR=0.44, 95% CrI: 0.33-0.58; HR=0.56, 95% CrI: 0.45-0.68; HR=0.45, 95% CrI: 0.32-0.61; HR=0.58, 95% CrI: 0.42-0.81; HR=0.50, 95% CrI: 0.37-0.68; respectively). However, there is no significant advantage compared with ribociclib plus letrozole (HR=1.00, 95% CrI: 0.72-1.39). In terms of ORR, ribociclib plus letrozole is more effective than palbociclib plus letrozole (odds ratio=1.30, 95% CrI: 0.83-2.02). Palbociclib plus letrozole and ribociclib plus letrozole might be the optimal first-line endocrine therapeutic choices for hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer due to a longer progression-free survival/time to progression and a more efficacious ORR.

Design of Ultrathin Pt-Based Multimetallic Nanostructures for Efficient Oxygen Reduction Electrocatalysis.

PubMed

Lai, Jianping; Guo, Shaojun

2017-12-01

Nanocatalysts with high platinum (Pt) utilization efficiency are attracting extensive attention for oxygen reduction reactions (ORR) conducted at the cathode of fuel cells. Ultrathin Pt-based multimetallic nanostructures show obvious advantages in accelerating the sluggish cathodic ORR due to their ultrahigh Pt utilization efficiency. A focus on recent important developments is provided in using wet chemistry techniques for making/tuning the multimetallic nanostructures with high Pt utilization efficiency for boosting ORR activity and durability. First, new synthetic methods for multimetallic core/shell nanoparticles with ultrathin shell sizes for achieving highly efficient ORR catalysts are reviewed. To obtain better ORR activity and stability, multimetallic nanowires or nanosheets with well-defined structure and surface are further highlighted. Furthermore, ultrathin Pt-based multimetallic nanoframes that feature 3D molecularly accessible surfaces for achieving more efficient ORR catalysis are discussed. Finally, the remaining challenges and outlooks for the future will be provided for this promising research field. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gewirth, Andrew A.; Kenis, Paul J.; Nuzzo, Ralph G.

In this research, we prosecuted a comprehensive plan of research directed at developing new catalysts and new understandings relevant to the operation of low temperature hydrogen-oxygen fuel cells. The focal point of this work was one centered on the Oxygen Reduction Reaction (ORR), the electrochemical process that most fundamentally limits the technological utility of these environmentally benign energy conversion devices. Over the period of grant support, we developed new ORR catalysts, based on Cu dimers and multimers. In this area, we developed substantial new insight into design rules required to establish better ORR materials, inspired by the three-Cu active sitemore » in laccase which has the highest ORR onset potential of any material known. We also developed new methods of characterization for the ORR on conventional (metal-based) catalysts. Finally, we developed a new platform to study the rate of proton transfer relevant to proton coupled electron transfer (PCET) reactions, of which the ORR is an exemplar. Other aspects of work involved theory and prototype catalyst testing.« less

Terrestrial habitat mapping of the Oak Ridge Reservation: 1996 Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington-Allen, R.A.; Ashwood, T.L.

1996-09-01

The US DOE is in the process of remediating historical contamination on the Oak Ridge Reservation (ORR). Two key components are ecological risk assessment and monitoring. In 1994 a strategy was developed and a specific program was initiated to implement the strategy for the terrestrial biota of the entire ORR. This document details results of the first task: development of a habitat map and habitat models for key species of interest. During the last 50 years ORR has been a relatively protected island of plant and animal habitats in a region of rapidly expanding urbanization. A preliminary biodiversity assessment ofmore » the ORR by the Nature Conservancy in 1995 noted 272 occurrences of significant plant and animal species and communities. Field surveys of threatened and endangered species show that the ORR contains 20 rare plant species, 4 of which are on the state list of endangered species. The rest are either on the state list of threatened species or listed as being of special concern. The ORR provides habitat for some 60 reptilian and amphibian species; more than 120 species of terrestrial birds; 32 species of waterfowl, wading birds, and shorebirds; and about 40 mammalian species. The ORR is both a refuge for rare species and a reservoir of recruitment for surrounding environments and wildlife management areas. Cedar barrens, river bluffs, and wetlands have been identified as the habitat for most rare vascular plant species on the ORR.« less

77 FR 15374 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-15

... the secondary migration of refugees within the United States after arrival. Further, INA 412(c)(1)(B... secondary migration. In order to meet the statutory requirements, ORR requires each state to submit... ranges. ORR used the information on the ORR-11 to measure secondary migration for the purposes of formula...

Immunotherapy in advanced melanoma: a network meta-analysis.

PubMed

Pyo, Jung-Soo; Kang, Guhyun

2017-05-01

The aim of this study was to compare the effects of various immunotherapeutic agents and chemotherapy for unresected or metastatic melanomas. We performed a network meta-analysis using a Bayesian statistical model to compare objective response rate (ORR) of various immunotherapies from 12 randomized controlled studies. The estimated ORRs of immunotherapy and chemotherapy were 0.224 and 0.108, respectively. The ORRs of immunotherapy in untreated and pretreated patients were 0.279 and 0.176, respectively. In network meta-analysis, the odds ratios for ORR of nivolumab (1 mg/kg)/ipilmumab (3 mg/kg), pembrolizumab 10 mg/kg and nivolumab 3 mg/kg were 8.54, 5.39 and 4.35, respectively, compared with chemotherapy alone. Our data showed that various immunotherapies had higher ORRs rather than chemotherapy alone.

Boron doped graphene wrapped silver nanowires as an efficient electrocatalyst for molecular oxygen reduction

PubMed Central

Nair, Anju K.; Thazhe veettil, Vineesh; Kalarikkal, Nandakumar; Thomas, Sabu; Kala, M. S.; Sahajwalla, Veena; Joshi, Rakesh K.; Alwarappan, Subbiah

2016-01-01

Metal nanowires exhibit unusually high catalytic activity towards oxygen reduction reaction (ORR) due to their inherent electronic structures. However, controllable synthesis of stable nanowires still remains as a daunting challenge. Herein, we report the in situ synthesis of silver nanowires (AgNWs) over boron doped graphene sheets (BG) and demonstrated its efficient electrocatalytic activity towards ORR for the first time. The electrocatalytic ORR efficacy of BG-AgNW is studied using various voltammetric techniques. The BG wrapped AgNWs shows excellent ORR activity, with very high onset potential and current density and it followed four electron transfer mechanism with high methanol tolerance and stability towards ORR. The results are comparable to the commercially available 20% Pt/C in terms of performance. PMID:27941954

Homogenous electrocatalytic oxygen reduction rates correlate with reaction overpotential in acidic organic solutions

DOE PAGES

Pegis, Michael L.; McKeown, Bradley A.; Kumar, Neeraj; ...

2016-10-28

Improvement of electrocatalysts for the oxygen reduction reaction (ORR) is critical for the advancement of fuel cell technologies. Herein, we report a series of eleven soluble iron porphyrin ORR electrocatalysts that possess turnover frequencies (TOFs) from 3 s -1 to an unprecedented 2.2 x 10 6 s -1. These TOFs correlate with the ORR overpotential, which can be changed by modulating the ancillary ligand, by varying the reaction conditions or by changing the catalyst’s protonation state. This is the first such correlation for homogeneous ORR electrocatalysis, and it demonstrates that the remarkably fast TOFs are a consequence of the highmore » overpotential. Computational studies indicate that the correlation is analogous to the volcano plot analysis developed for heterogeneous ORR materials. This unique parallel between homo- and heterogeneous ORR electrocatalysts allows a fundamental understanding of intrinsic barriers associated with the ORR, which can aid the design of new catalytic systems that operate at low overpotential. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. Additional data is given in the Electronic Supporting Information.« less

Phase II trial of capecitabine plus modified cisplatin (mXP) as first-line therapy in Japanese patients with metastatic gastric cancer (KSCC1104).

PubMed

Satake, Hironaga; Iwatsuki, Masaaki; Uenosono, Yoshikazu; Shiraishi, Takeshi; Tanioka, Hiroaki; Saeki, Hiroshi; Sugimachi, Keishi; Kitagawa, Dai; Shimokawa, Mototsugu; Oki, Eiji; Emi, Yasunori; Kakeji, Yoshihiro; Tsuji, Akihito; Akagi, Yoshito; Natsugoe, Shoji; Baba, Hideo; Maehara, Yoshihiko

2017-01-01

Capecitabine plus cisplatin (XP) is a standard therapy for metastatic gastric cancer (mGC). However, while results from previous phase III trials suggested that the cisplatin dosage should be reduced in Japanese patients, no clinical data exist to support this. Here, we conducted a multicenter study to evaluate the efficacy and safety of modified XP (mXP) in Japanese patients with mGC. Patients with previously untreated mGC received mXP (cisplatin 60 mg/m 2 on day 1 plus capecitabine 1000 mg/m 2 twice daily on days 1-14) every 3 weeks. The primary endpoint was the Response Evaluation Criteria in Solid Tumors-confirmed overall response rate (ORR). A sample size of 40 was planned for a threshold ORR of 30% and an expected value of 50%, with a one-sided α of 0.05 and a beta of approximately 0.2. Forty-two patients were enrolled. One patient did not fulfill the eligibility criteria; therefore, a total of 41 patients were assessed. The results were as follows: complete response in 2 patients, partial response in 16, stable disease in 14, progressive disease in 8, and no evaluation in 1. The confirmed ORR was 43.9% (95% confidence interval 28.7-59.1%). The median progression-free survival and median overall survival were 4.6 and 11.3 months, respectively. The most common grade 3 or 4 adverse events were neutropenia (37.5%), anemia (24.4%), anorexia (24.4%), and nausea (12.2%). First-line chemotherapy with mXP in Japanese patients with mGC did not reach its primary objective. However, it did show a promising response rate and an acceptable tolerability profile.

Well-Defined Metal-O6 in Metal-Catecholates as a Novel Active Site for Oxygen Electroreduction.

PubMed

Liu, Xuan-He; Hu, Wei-Li; Jiang, Wen-Jie; Yang, Ya-Wen; Niu, Shuai; Sun, Bing; Wu, Jing; Hu, Jin-Song

2017-08-30

Metal-nitrogen coordination sites, M-N x (M = Fe, Co, Ni, etc.), have shown great potential to replace platinum group materials as electrocatalysts for oxygen reduction reaction (ORR). However, the real active site in M-N x is still vague to date due to their complicated structure and composition. It is therefore highly desirable but challenging to develop ORR catalysts with novel and clear active sites, which could meet the needs of comprehensive understanding of structure-function relationships and explore new cost-effective and efficient ORR electrocatalysts. Herein, well-defined M-O 6 coordination in metal-catecholates (M-CATs, M = Ni or Co) is discovered to be catalytically active for ORR via a four-electron-dominated pathway. In view of no pyrolysis involved and unambiguous crystalline structure of M-CATs, the M-O 6 octahedral coordination site with distinct structure is determined as a new type of active site for ORR. These findings extend the scope of metal-nonmetal coordination as an active site for ORR and pave a way for bottom-up design of novel electrocatalysts containing M-O 6 coordination.

Fe3C nanoparticle decorated Fe/N doped graphene for efficient oxygen reduction reaction electrocatalysis

NASA Astrophysics Data System (ADS)

Niu, Yanli; Huang, Xiaoqin; Hu, Weihua

2016-11-01

Oxygen reduction reaction (ORR) electrocatalysts with high activity, low cost and good durability are crucial to promote the large-scale practical application of fuel cells. Particularly, iron carbide (Fe3C) supported on nitrogen-doped carbon has recently demonstrated compelling promise for ORR electrocatalysis. In this paper, we report the facile synthesis of mesoporous Fe/N-doped graphene with encapsulated Fe3C nanoparticles (Fe3C@Fe/N-graphene) and its superior ORR catalytic activity. This hybrid material was synthesized by the spontaneous oxidative polymerization of dopamine on graphene oxide (GO) sheets in the presence of iron ion, followed by thermal annealing in Argon (Ar) atmosphere. As-prepared material shows high ORR catalytic activity with overwhelming four-electron reduction pathway, long-term durability and high methanol tolerance in alkaline media. This work reports a facile method to synthesize promising ORR electrocatalysis with multiple components and hierarchical architecture, and may offer valuable insight into the underlying mechanism of Fe3C-boosted ORR activity of Fe/N doped carbon.

Survey of protected vascular plants on the Oak Ridge Reservation, Oak Ridge, Tennessee

DOE Office of Scientific and Technical Information (OSTI.GOV)

Awl, D.J.; Pounds, L.R.; Rosensteel, B.A.

Vascular plant surveys were initiated during fiscal year 1992 by the environmentally sensitive areas program to determine the baseline condition of threatened and endangered (T&E) vascular plant species on the Oak Ridge Reservation (ORR). T&E species receive protection under federal and state regulations. In addition, the National Environmental Policy Act (NEPA) requires that federally-funded projects avoid or mitigate impacts to listed species. T&E plant species found on or near the U.S. Department of Energy`s (DOE) Oak Ridge Reservation (ORR) are identified. Twenty-eight species identified on the ORR are listed by the Tennessee Department of Environment and Conservation as either endangered,more » threatened, or of special concern. Four of these have been under review by the U.S. Fish and Wildlife Service for possible listing (listed in the formerly-used C2 candidate category). Additional species listed by the state occur near and may be present on the ORR. A range of habitats support the rare taxa on the ORR: river bluffs, sinkholes, calcareous barrens, wetlands, utility corridors, and forests. The list of T&E plant species and their locations on the ORR should be considered provisional because the entire ORR has not been surveyed, and state and federal status of all species continues to be updated. The purpose of this document is to present information on the listed T&E plant species currently known to occur on the ORR as well as listed species potentially occurring on the ORR based on geographic range and habitat availability. For the purpose of this report, {open_quotes}T&E species{close_quotes} include all federal- and state-listed species, including candidates for listing, and species of special concern. Consideration of T&E plant habitats is an important component of resource management and land-use planning; protection of rare species in their natural habitat is the best method of ensuring their long-term survival.« less

Report of the oversight assessment of the operational readiness review of the Savannah River Site Defense Waste Processing Facility Cold Chemical Runs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, B.

1993-03-01

This report presents the results of an oversight assessment (OA) conducted by the US Department of Energy`s (DOE) Office of Environment, Safety and Health (EH) of the operational readiness review (ORR) activities for the Cold Chemical Runs (CCRs) at the Defense Waste Processing Facility (DWPF) located at Savannah River Site (SRS). The EH OA of this facility took place concurrently with an ORR performed by the DOE Office of Environmental Restoration and Waste Management (EM). The EM ORR was conducted from September 28, 1992, through October 9, 1992, although portions of the EM ORR were extended beyond this period. Themore » EH OA evaluated the comprehensiveness and effectiveness of the EM ORR. The EH OA was designed to ascertain whether the EM ORR was thorough and demonstrated sufficient inquisitiveness to verify that the implementation of programs and procedures is adequate to assure the protection of worker safety and health. The EH OA was carried out in accordance with the protocol and procedures of the ``EH Program for Oversight Assessment of Operational Readiness Evaluations for Startups and Restarts,`` dated September 15, 1992. Based on its OA and verification of the resolution of EH OA findings, the EH OA Team believes that the startup of the CCRs may be safely begun, pending satisfactory completion and verification of the prestart findings identified by the EM ORR. The EH OA was based primarily on an evaluation of the comprehensiveness and effectiveness of the EM ORR and addressed the following areas: industrial safety, industrial hygiene, and respiratory protection; fire protection; and chemical safety. The EH OA conducted independent ``vertical-slice`` reviews to confirm EM ORR results in the areas of confined-space entry, respiratory protection, fire protection, and chemical safety.« less

Correlation of KIT and PDGFRA mutational status with clinical benefit in patients with gastrointestinal stromal tumor treated with sunitinib in a worldwide treatment-use trial.

PubMed

Reichardt, Peter; Demetri, George D; Gelderblom, Hans; Rutkowski, Piotr; Im, Seock-Ah; Gupta, Sudeep; Kang, Yoon-Koo; Schöffski, Patrick; Schuette, Jochen; Soulières, Denis; Blay, Jean-Yves; Goldstein, David; Fly, Kolette; Huang, Xin; Corsaro, Massimo; Lechuga, Maria Jose; Martini, Jean-Francois; Heinrich, Michael C

2016-01-15

Several small studies indicated that the genotype of KIT or platelet-derived growth factor receptor-α (PDGFRA) contributes in part to the level of clinical effectiveness of sunitinib in gastrointestinal stromal tumor (GIST) patients. This study aimed to correlate KIT and PDGFRA mutational status with clinical outcome metrics (progression-free survival [PFS], overall survival [OS], objective response rate [ORR]) in a larger international patient population. This is a non-interventional, retrospective analysis in patients with imatinib-resistant or intolerant GIST who were treated in a worldwide, open-label treatment-use study (Study 1036; NCT00094029) in which sunitinib was administered at a starting dose of 50 mg/day on a 4-week-on, 2-week-off schedule. Molecular status was obtained in local laboratories with tumor samples obtained either pre-imatinib, post-imatinib/pre-sunitinib, or post-sunitinib treatment, and all available data were used in the analyses regardless of collection time. The primary analysis compared PFS in patients with primary KIT exon 11 versus exon 9 mutations (using a 2-sided log-rank test) and secondary analyses compared OS (using the same test) and ORR (using a 2-sided Pearson χ(2) test) in the same molecular subgroups. Of the 1124 sunitinib-treated patients in the treatment-use study, 230 (20%) were included in this analysis, and baseline characteristics were similar between the two study populations. Median PFS was 7.1 months. A significantly better PFS was observed in patients with a primary mutation in KIT exon 9 (n = 42) compared to those with a primary mutation in exon 11 (n = 143; hazard ratio = 0.59; 95 % confidence interval, 0.39-0.89; P = 0.011), with median PFS times of 12.3 and 7.0 months, respectively. Similarly, longer OS and higher ORR were observed in patients with a primary KIT mutation in exon 9 versus exon 11. The data available were limited to investigate the effects of additional KIT or PDGFRA mutations on the efficacy of sunitinib treatment. This large retrospective analysis confirms the prognostic significance of KIT mutation status in patients with GIST. This analysis also confirms the effectiveness of sunitinib as a post-imatinib therapy, regardless of mutational status. NCT01459757.

Resource management plan for the Oak Ridge Reservation. Volume 29, Rare plants on the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunningham, M.; Pounds, L.; Oberholster, S.

Rare plant species listed by state or federal agencies and found on or near the Department of Energy`s Oak Ridge Reservation (ORR) are identified. Seventeen species present on the ORR are listed by the Tennessee Department of Environment and Conservation as either endangered, threatened, or of special concern. Four of these are under review by the US Fish and Wildlife Service for possible listing as threatened or endangered species. Ten species listed by the state occur near and may be present on the ORR; four are endangered in Tennessee, and one is a candidate for federal listing. A range ofmore » habitats supports the rare taxa on the ORR: River bluffs, calcareous barrens, wetlands, and deciduous forest. Sites for listed rare species on the ORR have been designated as Research Park Natural Areas. Consideration of rare plant habitats is an important component of resource management and land-use planning; protection of rare species in their natural habitat is the best method of ensuring their long-term survival. In addition, the National Environmental Policy Act requires that federally funded projects avoid or mitigate impacts to listed species. The list of rare plant species and their location on the ORR should be considered provisional because the entire ORR has not been surveyed, and state and federal status of all species continues to be updated.« less

Emerging Beliefs Frustrate Ecological Literacy and Meaning-Making for Students

ERIC Educational Resources Information Center

Fleischer, Stuart

2011-01-01

In their treatise, Mitchell and Mueller extend David Orr's notions of ecological literacy (2005) to include biophilia (Wilson "1984") and ecojustice (Mueller "2009"). In his writings, David Orr claims that the US is in an "ecological crisis" and that this stems from a crisis of education. The authors outline Orr's theory of ecological literacy as…

Resource Management plan for the Oak Ridge Reservation. Volume 28, Wetlands on the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunningham, M.; Pounds, Larry

1991-12-01

A survey of wetlands on the Oak Ridge Reservation (ORR) was conducted in 1990. Wetlands occurring on ORR were identified using National Wetlands Inventory (NWI) maps and field surveys. More than 120 sites were visited and 90 wetlands were identified. Wetland types on ORR included emergent communities in shallow embayments on reservoirs, emergent and aquatic communities in ponds, forested wetland on low ground along major creeks, and wet meadows and marshes associated with streams and seeps. Vascular plant species occurring on sites visited were inventoried, and 57 species were added to the checklist of vascular plants on ORR. Three speciesmore » listed as rare in Tennessee were discovered on ORR during the wetlands survey. The survey provided an intensive ground truth of the wetlands identified by NWI and offered an indication of wetlands that the NWI remote sensing techniques did not detect.« less

From melamine sponge towards 3D sulfur-doping carbon nitride as metal-free electrocatalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Xu, Jingjing; Li, Bin; Li, Songmei; Liu, Jianhua

2017-07-01

Development of new and efficient metal-free electrocatalysts for replacing Pt to improve the sluggish kinetics of oxygen reduction reaction (ORR) is of great importance to emerging renewable energy technologies such as metal-air batteries and polymer electrolyte fuel cells. Herein, 3D sulfur-doping carbon nitride (S-CN) as a novel metal-free ORR electrocatalyst was synthesized by exploiting commercial melamine sponge as raw material. The sulfur atoms were doping on CN networks uniformly through numerous S-C bonds which can provide additional active sites. And it was found that the S-CN exhibited high catalytic activity for ORR in term of more positive onset potential, higher electron transfer number and higher cathodic density. This work provides a novel choice of metal-free ORR electrocatalysts and highlights the importance of sulfur-doping CN in metal-free ORR electrocatalysts.

Enhancement of ORR catalytic activity by multiple heteroatom-doped carbon materials.

PubMed

Kim, Dae-wook; Li, Oi Lun; Saito, Nagahiro

2015-01-07

Heteroatom-doped carbon matrices have been attracting significant attention due to their superior electrochemical stability, light weight and low cost. Hence, in this study, various types of heteroatom, including single dopants of N, B and P and multiple dopants of B-N and P-N with a carbon matrix were synthesized by an innovative method named the solution plasma process. The heteroatom was doped into the carbon matrix during the discharge process by continuous dissociation and recombination of precursors. The chemical bonding structure, ORR activity and electrochemical performance were compared in detail for each single dopant and multiple dopants. According to the Raman spectra, the carbon structures were deformed by the doped heteroatoms in the carbon matrix. In comparison with N-doped structures (NCNS), the ORR potential of PN-doped structures (PNCNS) was positively shifted from -0.27 V to -0.24 V. It was observed that doping with N decreased the bonding between P and C in the matrix. The multiple doping induced additional active sites for ORR which further enhanced ORR activity and stability. Therefore, PNCNS is a promising metal-free catalyst for ORR at the cathode in a fuel cell.

Solution-based synthesis and design of late transition metal chalcogenide materials for oxygen reduction reaction (ORR).

PubMed

Gao, Min-Rui; Jiang, Jun; Yu, Shu-Hong

2012-01-09

Late transition metal chalcogenide (LTMC) nanomaterials have been introduced as a promising Pt-free oxygen reduction reaction (ORR) electrocatalysts because of their low cost, good ORR activity, high methanol tolerance, and facile synthesis. Herein, an overview on the design and synthesis of LTMC nanomaterials by solution-based strategies is presented along with their ORR performances. Current solution-based synthetic approaches towards LTMC nanomaterials include a hydrothermal/solvothermal approach, single-source precursor approach, hot-injection approach, template-directed soft synthesis, and Kirkendall-effect-induced soft synthesis. Although the ORR activity and stability of LTMC nanomaterials are still far from what is needed for practical fuel-cell applications, much enhanced electrocatalytic performance can be expected. Recent advances have emphasized that decorating the surface of the LTMC nanostructures with other functional nanoparticles can lead to much better ORR catalytic activity. It is believed that new synthesis approaches to LTMCs, modification techniques of LTMCs, and LTMCs with desirable morphology, size, composition, and structures are expected to be developed in the future to satisfy the requirements of commercial fuel cells. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoassisted oxygen reduction reaction on mpg-C3N4: The effects of elements doping on the performance of ORR

NASA Astrophysics Data System (ADS)

He, Qiuchen; Zhou, Feng; Zhan, Su; Huang, Naibao; Tian, Yu

2018-02-01

The oxygen reduction reaction (ORR) is a crux step in the fuel cells, which is limited to the catalysts. Low-cost nonmetal inorganic catalysts were considered to be the best prospect that may replace platinum. Graphitic carbon nitride (g-C3N4), which has wide prospect in photocatalysis, was found with the activity of ORR. In calculation work, we used the elements of the VIA family (O, S, and Se) to dope g-C3N4 and investigated the electronic properties and the ability of O2 adsorption in details based on the first principle. The result suggested that the performance of ORR of g-C3N4 may be enhanced by O doping, which can uplift the Fermi level of g-C3N4 and weaken the OH- absorption ability to enhance the O2 adsorption ability. After that, we synthetised O/g-C3N4 and S/g-C3N4 to test their ORR performance. According to the result, O doping can significantly enhance the performance of ORR of g-C3N4 which correspond with the calculation result. Then, the photo-assistant method was used to further enhance the ORR of g-C3N4 which was caused by the transition of the photo-induced electrons of g-C3N4 from VB to CB.

Earth Observations taken by the Expedition Seven crew

NASA Image and Video Library

2003-06-06

ISS007-E-06305 (6 June 2003) --- This image featuring two capital cities on opposite banks of the Congo River was taken by an Expedition 7 crewmember onboard the International Space Station (ISS). The smaller city is Brazzaville on the north side of the river, and Kinshasa on the south side. The cities lie at the downstream end of an almost circular widening in the river known as Stanley Pool. The international boundary follows the south shore of the pool (~30 kilometers in diameter). The Congo River exits the pool through a markedly narrowed channel at a series of whitewater rapids that can be seen in this view from space.

Synthesis and characterization of high performing Fe-N-C catalyst for oxygen reduction reaction (ORR) in Alkaline Exchange Membrane Fuel Cells

NASA Astrophysics Data System (ADS)

Hossen, Md Mosaddek; Artyushkova, Kateryna; Atanassov, Plamen; Serov, Alexey

2018-01-01

In this article, three different Fe-N-C oxygen reduction reaction (ORR) catalysts derived from different organic molecules i.e. Fe-NMG, Fe-NMP, Fe-MBZ have been synthesized, characterized by physical-chemical methods and studied in the reaction of oxygen reduction (ORR). It is found that Fe-NMG shows higher ORR performance than Fe-NMP and Fe-MBZ, by both rotating ring disk electrode (RRDE) and fuel cell tests. From characterization and surface analysis, it can be explained that the presence of higher amount of surface oxides and pyridinic nitrogen is the main reason for better performance towards ORR in alkaline media. To achieve the highest performance in alkaline exchange membrane fuel cell (AEMFC), the optimization of catalyst layer composition using various concentrations of ionomer (Tokuyama, AS4) was performed. At the optimum cathode layer configuration utilizing Fe-NMG produces the peak power density of 218 mWcm-2, which is one of the highest values presented in the open literature.

A Nanopore-Structured Nitrogen-Doped Biocarbon Electrocatalyst for Oxygen Reduction from Two-Step Carbonization of Lemna minor Biomass

NASA Astrophysics Data System (ADS)

Guo, Chaozhong; Li, Zhongbin; Niu, Lidan; Liao, Wenli; Sun, Lingtao; Wen, Bixia; Nie, Yunqing; Cheng, Jing; Chen, Changguo

2016-05-01

So far, the development of highly active and stable carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace commercial Pt/C catalyst is a hot topic. In this study, a new nanoporous nitrogen-doped carbon material was facilely designed by two-step pyrolysis of the renewable Lemna minor enriched in crude protein under a nitrogen atmosphere. Electrochemical measurements show that the onset potential for ORR on this carbon material is around 0.93 V (versus reversible hydrogen electrode), slightly lower than that on the Pt/C catalyst, but its cycling stability is higher compared to the Pt/C catalyst in an alkaline medium. Besides, the ORR at this catalyst approaches to a four-electron transfer pathway. The obtained ORR performance can be basically attributed to the formation of high contents of pyridinic and graphitic nitrogen atoms inside this catalyst. Thus, this work opens up the path in the ORR catalysis for the design of nitrogen-doped carbon materials utilizing aquatic plants as starting precursors.

Nitrogen-doped graphene anchored with mixed growth patterns of CuPt alloy nanoparticles as a highly efficient and durable electrocatalyst for the oxygen reduction reaction in an alkaline medium.

PubMed

Illathvalappil, Rajith; Dhavale, Vishal M; Bhange, Siddheshwar N; Kurungot, Sreekumar

2017-07-06

A highly active and durable CuPt alloy catalyst with trigonal bipyramidal and truncated cube-type mixed morphologies, anchored on the nitrogen-doped graphene (NGr) surface (CuPt-TBTC/NGr), was prepared by a simple and fast method. The obtained CuPt alloy showed improved oxygen reduction reaction (ORR) activity, with a 30 mV positive shift in the half-wave potential value, as compared to the state-of-the-art Pt/C catalyst in a 0.1 M KOH solution. The CuPt alloy with the trigonal bipyramidal morphology possesses porous type inter-connected sides, which help to achieve improved mass transport of oxygen during the ORR. The exposure of the (111) plane of the CuPt alloy further improved the catalytic activity towards the dioxygen reduction in alkaline media. The ORR activity of the NGr-supported CuPt alloy was found to be dependent on the reaction time, and improved activity was obtained on the material derived at a reaction time of 90 min (CuPt-TBTC/NGr-90). The material synthesized at a lower or higher reaction time than 90 min resulted in a partially formed trigonal bipyramidal morphology with more truncated cubes or agglomerated trigonal bipyramidal and truncated cubes with closed type structures, respectively. Along with the high intrinsic ORR activity, CuPt-TBTC/NGr-90 displayed excellent electrochemical stability. Even after repeated 1000 potential cycling in a window ranging from 0.10 to 1.0 V (vs. RHE), the system clearly outperformed the state-of-the-art Pt/C catalyst with 15 and 60 mV positive shifts in the onset and half-wave potentials, respectively. CuPt-TBTC/NGr-90 also exhibited 2.1 times higher mass activity and 2.2 times higher specific activity, compared to Pt/C at 0.90 V (vs. RHE). Finally, a zinc-air battery fabricated with the alloy catalyst as the air electrode displayed a peak power density of 300 mW cm -2 , which is much higher than the peak power density of 253 mW cm -2 obtained for the state-of-the-art Pt/C catalyst as the air electrode.

Metal-Free Carbon-Based Materials: Promising Electrocatalysts for Oxygen Reduction Reaction in Microbial Fuel Cells

PubMed Central

Sawant, Sandesh Y.; Han, Thi Hiep; Cho, Moo Hwan

2016-01-01

Microbial fuel cells (MFCs) are a promising green approach for wastewater treatment with the simultaneous advantage of energy production. Among the various limiting factors, the cathodic limitation, with respect to performance and cost, is one of the main obstacles to the practical applications of MFCs. Despite the high performance of platinum and other metal-based cathodes, their practical use is limited by their high cost, low stability, and environmental toxicity. Oxygen is the most favorable electron acceptor in the case of MFCs, which reduces to water through a complicated oxygen reduction reaction (ORR). Carbon-based ORR catalysts possessing high surface area and good electrical conductivity improve the ORR kinetics by lowering the cathodic overpotential. Recently, a range of carbon-based materials have attracted attention for their exceptional ORR catalytic activity and high stability. Doping the carbon texture with a heteroatom improved their ORR activity remarkably through the favorable adsorption of oxygen and weaker molecular bonding. This review provides better insight into ORR catalysis for MFCs and the properties, performance, and applicability of various metal-free carbon-based electrocatalysts in MFCs to find the most appropriate cathodic catalyst for the practical applications. The approaches for improvement, key challenges, and future opportunities in this field are also explored. PMID:28029116

Surface Proton Transfer Promotes Four-Electron Oxygen Reduction on Gold Nanocrystal Surfaces in Alkaline Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Fang; Zhang, Yu; Liu, Shizhong

Four-electron oxygen reduction reaction (4e-ORR), as a key pathway in energy conversion, is preferred over the two-electron reduction pathway that falls short in dissociating dioxygen molecules. Gold (Au) surfaces exhibit high sensitivity of the ORR pathway to its atomic structures. The long-standing puzzle remains unsolved why the Au surfaces with {100} sub-facets were exceptionally capable to catalyze the 4e-ORR in alkaline solution, though limited within a narrow potential window. Herein we report the discovery of a dominant 4e-ORR over the whole potential range on {310} surface of Au nanocrystal shaped as truncated ditetragonal prism (TDP). In contrast, ORR pathways onmore » single-crystalline facets of shaped nanoparticles, including {111} on nano-octahedra and {100} on nano-cubes, are similar to their single-crystal counterparts. Combining our experimental results with density functional theory calculations, we elucidate the key role of surface proton transfers from co-adsorbed H 2O molecules in activating the facet- and potential-dependent 4e ORR on Au in alkaline solutions. These results elucidate how surface atomic structures determine the reaction pathways via bond scission and formation among weakly adsorbed water and reaction intermediates. The new insight helps in developing facet-specific nanocatalysts for various reactions.« less

Nitrogen and Phosphorus Codoped Mesoporous Carbon Derived from Polypyrrole as Superior Metal-Free Electrocatalyst toward the Oxygen Reduction Reaction.

PubMed

Zhang, Zhengping; Sun, Junting; Dou, Meiling; Ji, Jing; Wang, Feng

2017-05-17

To replace high-cost platinum group metal (PGM) electrocatalysts for oxygen reduction reaction (ORR) that is the crucial cathode reaction in fuel cell technology and metal-air battery, the development of low-cost and high-efficiency non-PGM catalysts for ORR has attracted much attention during the past decades. As one of the promising candidates, N-doped carbon is highly desirable for its strong designability and outstanding catalytic activity and stability. In this work, a facile and rational strategy is demonstrated for preparation of N,P-codoped mesoporous carbon (N,P-MC) for ORR by the direct pyrolysis treatment of polypyrrole with phytic acid as P-dopant and polystyrene sphere as template. The resultant N,P-MC exhibits a mesoporous structure with the optimized ORR active sites originating from the N,P-codoping. Owing to these features, N,P-MC exhibits excellent ORR activity, remarkable electrochemical stability, and superior methanol tolerance, comparable or even better than that of commercial Pt/C catalyst. The origin of enhanced ORR performance can be attributed to both the increased active sites and the mesoporous structure, which is expected to guide the future preparation of more capable carbon-based electrocatalysts for oxygen reduction and other electrocatalytic application.

One-pot synthesis of a PtPd dendritic nanocube cage superstructure on graphenes as advanced catalysts for oxygen reduction

NASA Astrophysics Data System (ADS)

Zheng, Yuanyuan; Qiao, Junhua; Yuan, Junhua; Shen, Jianfeng; Wang, Ai-Jun; Gong, Peijun

2018-03-01

How to use Pt economically and efficiently in the oxygen reduction reaction (ORR) is of theoretical and practical significance for the industrialization of the proton-exchange membrane fuel cells. In order to minimize Pt consumption and optimize the ORR performance, the ORR catalysts are recommended to be designed as a porous nanostructure. Herein, we report a one-pot solvothermal strategy to prepare PtPd dendritic nanocube cages via a galvanic replacement mechanism triggered by an I- ion. These PtPd alloy crystals are nanoporous, and uniformly dispersed on reduced graphene oxides (RGOs). The size of the PtPd dendritic nanocube cages can be easily tuned from 20-80 nm by controlling their composition. Their composition is optimized to be 1:5 Pt/Pd atomic ratio for these RGO-supported PtPd dendritic nanocages. This catalyst shows superior ORR performance with a specific activity of 2.01 mA cm-2 and a mass activity of 4.45 A mg-1 Pt, far above those for Pt/C catalysts (0.288 mA cm-2 for specific activity, and 0.21 A mg-1 Pt for mass activity). In addition to ORR activity, it also exhibits robust durability with almost negligible decay in ORR mass activity after 10 000 voltammetric cycling.

General Solvent-dependent Strategy toward Enhanced Oxygen Reduction Reaction in Graphene/Metal Oxide Nanohybrids: Effects of Nitrogen-containing Solvent

NASA Astrophysics Data System (ADS)

Kao, Wei-Yao; Chen, Wei-Quan; Chiu, Yu-Hsiang; Ho, Yu-Hsuan; Chen, Chun-Hu

2016-11-01

A general solvent-dependent protocol directly influencing the oxygen reduction reaction (ORR) in metal oxide/graphene nanohybrids has been demonstrated. We conducted the two-step synthesis of cobalt oxide/N-doped graphene nanohybrids (CNG) with solvents of water, ethanol, and dimethylformamide (DMF), representing tree typical categories of aqueous, polar organic, and organic N-containing solvents commonly adopted for graphene nanocomposites preparation. The superior ORR performance of the DMF-hybrids can be attributed to the high nitrogen-doping, aggregation-free hybridization, and unique graphene porous structures. As DMF is the more effective N-source, the spectroscopic results support a catalytic nitrogenation potentially mediated by cobalt-DMF coordination complexes. The wide-distribution of porosity (covering micro-, meso-, to macro-pore) and micron-void assembly of graphene may further enhance the diffusion kinetics for ORR. As the results, CNG by DMF-synthesis exhibits the high ORR activities close to Pt/C (i.e. only 8 mV difference of half-wave potential with electron transfer number of 3.96) with the better durability in the alkaline condition. Additional graphene hybrids comprised of iron and manganese oxides also show the superior ORR activities by DMF-synthesis, confirming the general solvent-dependent protocol to achieve enhanced ORR activities.

General Solvent-dependent Strategy toward Enhanced Oxygen Reduction Reaction in Graphene/Metal Oxide Nanohybrids: Effects of Nitrogen-containing Solvent

PubMed Central

Kao, Wei-Yao; Chen, Wei-Quan; Chiu, Yu-Hsiang; Ho, Yu-Hsuan; Chen, Chun-Hu

2016-01-01

A general solvent-dependent protocol directly influencing the oxygen reduction reaction (ORR) in metal oxide/graphene nanohybrids has been demonstrated. We conducted the two-step synthesis of cobalt oxide/N-doped graphene nanohybrids (CNG) with solvents of water, ethanol, and dimethylformamide (DMF), representing tree typical categories of aqueous, polar organic, and organic N-containing solvents commonly adopted for graphene nanocomposites preparation. The superior ORR performance of the DMF-hybrids can be attributed to the high nitrogen-doping, aggregation-free hybridization, and unique graphene porous structures. As DMF is the more effective N-source, the spectroscopic results support a catalytic nitrogenation potentially mediated by cobalt-DMF coordination complexes. The wide-distribution of porosity (covering micro-, meso-, to macro-pore) and micron-void assembly of graphene may further enhance the diffusion kinetics for ORR. As the results, CNG by DMF-synthesis exhibits the high ORR activities close to Pt/C (i.e. only 8 mV difference of half-wave potential with electron transfer number of 3.96) with the better durability in the alkaline condition. Additional graphene hybrids comprised of iron and manganese oxides also show the superior ORR activities by DMF-synthesis, confirming the general solvent-dependent protocol to achieve enhanced ORR activities. PMID:27853187

Surface Proton Transfer Promotes Four-Electron Oxygen Reduction on Gold Nanocrystal Surfaces in Alkaline Solution

DOE PAGES

Lu, Fang; Zhang, Yu; Liu, Shizhong; ...

2017-05-11

Four-electron oxygen reduction reaction (4e-ORR), as a key pathway in energy conversion, is preferred over the two-electron reduction pathway that falls short in dissociating dioxygen molecules. Gold (Au) surfaces exhibit high sensitivity of the ORR pathway to its atomic structures. The long-standing puzzle remains unsolved why the Au surfaces with {100} sub-facets were exceptionally capable to catalyze the 4e-ORR in alkaline solution, though limited within a narrow potential window. Herein we report the discovery of a dominant 4e-ORR over the whole potential range on {310} surface of Au nanocrystal shaped as truncated ditetragonal prism (TDP). In contrast, ORR pathways onmore » single-crystalline facets of shaped nanoparticles, including {111} on nano-octahedra and {100} on nano-cubes, are similar to their single-crystal counterparts. Combining our experimental results with density functional theory calculations, we elucidate the key role of surface proton transfers from co-adsorbed H 2O molecules in activating the facet- and potential-dependent 4e ORR on Au in alkaline solutions. These results elucidate how surface atomic structures determine the reaction pathways via bond scission and formation among weakly adsorbed water and reaction intermediates. The new insight helps in developing facet-specific nanocatalysts for various reactions.« less

Pooled Analysis of CNS Response to Alectinib in Two Studies of Pretreated Patients With ALK-Positive Non-Small-Cell Lung Cancer.

PubMed

Gadgeel, Shirish M; Shaw, Alice T; Govindan, Ramaswamy; Gandhi, Leena; Socinski, Mark A; Camidge, D Ross; De Petris, Luigi; Kim, Dong-Wan; Chiappori, Alberto; Moro-Sibilot, Denis L; Duruisseaux, Michael; Crino, Lucio; De Pas, Tommaso; Dansin, Eric; Tessmer, Antje; Yang, James Chih-Hsin; Han, Ji-Youn; Bordogna, Walter; Golding, Sophie; Zeaiter, Ali; Ou, Sai-Hong Ignatius

2016-12-01

Purpose Alectinib has shown activity in the CNS in phase I and II studies. To further evaluate this activity, we pooled efficacy and safety data from two single-arm phase II studies (NP28761 and NP28673; ClinicalTrials.gov identifiers: NCT01871805 and NCT01801111, respectively) in patients with ALK-positive non-small-cell lung cancer (NSCLC). Patients and Methods Both studies included patients with ALK-positive NSCLC who had previously received crizotinib; all patients received alectinib 600 mg twice per day. The primary end point in both studies was independent review committee (IRC)-assessed objective response rate (ORR; by Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1). Additional end points (all by IRC) included CNS ORR (CORR), CNS disease control rate (CDCR), and CNS duration of response (CDOR). Results One hundred thirty-six patients had baseline CNS metastases (60% of the overall study populations); 50 patients (37%) had measurable CNS disease at baseline. Ninety-five patients (70%) had prior CNS radiotherapy; 55 patients completed the CNS radiotherapy more than 6 months before starting alectinib. Median follow-up time was 12.4 months (range, 0.9 to 19.7 months). For patients with baseline measurable CNS disease, IRC CORR was 64.0% (95% CI, 49.2% to 77.1%), CDCR was 90.0% (95% CI, 78.2% to 96.7%), and median CDOR was 10.8 months (95% CI, 7.6 to 14.1 months). For patients with measurable and/or nonmeasurable baseline CNS disease, IRC CORR was 42.6% (95% CI, 34.2% to 51.4%), CDCR was 85.3% (95% CI, 78.2% to 90.8%), and median CDOR was 11.1 months (95% CI, 10.3 months to not evaluable). CORR was 35.8% (95% CI, 26.2% to 46.3%) for patients with prior radiotherapy (n = 95) and 58.5% (95% CI, 42.1% to 73.7%) for patients without prior radiotherapy (n = 41). As previously reported, alectinib was well tolerated, regardless of baseline CNS disease. Conclusion Alectinib showed good efficacy against CNS metastases, in addition to systemic activity, in crizotinib-refractory ALK-positive NSCLC.

Comparison of single agent versus combined chemotherapy in previously treated patients with advanced urothelial carcinoma: a meta-analysis.

PubMed

Wu, Xiao-Jun; Zhi, Yi; He, Peng; Zhou, Xiao-Zhou; Zheng, Ji; Chen, Zhi-Wen; Zhou, Zhan-Song

2016-01-01

Platinum-based chemotherapy is the standard treatment for advanced urothelial cancer (UC) and is generally used in the first-line setting. However, the optimal salvage treatment for previously treated UC patients is unclear. We conducted a systematic review of published clinical trials of single agent versus combined chemotherapy as salvage treatment in previously treated UC patients. Trials published between 1994 and 2015 were identified by an electronic search of public databases (MEDLINE, EMBASE, Cochrane library). All relevant studies were independently identified by two authors for inclusion. Demographic data, treatment regimens, objective response rate (ORR), disease control rate (DCR), median progression-free and overall survival (PFS, OS), and grade 3/4 toxicities were extracted and analyzed using Comprehensive Meta Analysis software (Version 2.0). Fifty cohorts with 1,685 patients were included for analysis: 814 patients were treated with single agent chemotherapy and 871 with combined chemotherapy. Pooled OS was significantly higher at 1 year for combined chemotherapy than for single agent (relative risk [RR] 1.52; 95% CI: 1.01-2.37; P=0.03) but not for 2-year OS (RR 1.31; 95% CI: 0.92-1.85; P=0.064). Additionally, combined chemotherapy significantly improved ORR (RR 2.25; 95% CI: 1.60-3.18; P<0.001) and DCR (RR 1.12; 95% CI: 1.01-1.25, P=0.033) compared to single agent for advanced UC patients. As for grade 3 and 4 toxicities, more frequencies of leukopenia and thrombocytopenia were observed in the combined chemotherapy than in single agent group, while equivalent frequencies of anemia, nausea, vomiting, and diarrhea were found between the two groups. In comparison with single agent alone, combined chemotherapy as salvage treatment for advanced UC patients significantly improved ORR, DCR, and 1-year OS, but not 2-year OS. Our findings support the need to compare combined chemotherapy with single agent alone in the salvage setting in large prospective trials due to its potential survival benefit in advanced UC patients.

Juvenile anadromous salmonid production in upper Columbia River side channels with different levels of hydrological connection

USGS Publications Warehouse

Martens, Kyle D.; Connolly, Patrick J.

2014-01-01

We examined the contribution of three types of side channels based on their hydrologic connectivity (seasonally disconnected, partially connected, and connected) to production of juvenile anadromous salmonids. Juvenile steelhead Oncorhynchus mykiss and Chinook Salmon O. tshawytscha were found in all three of these side channel types and in each year of the study. Upon connection with the main stem at high flows, the seasonally disconnected side channels experienced an emptying out of the previous year's fish while filling with young-of-year fish during the 2- to 4-month period of hydrologic connection. There were no differences between the densities of juvenile steelhead and Chinook Salmon and the rate of smolts produced among the three types of side channels. Recently reintroduced Coho Salmon O. kisutch had sporadic presence and abundance in partially and connected side channels, but the smolt production rate was over two times that of steelhead and Chinook Salmon in seasonally disconnected side channels. Within seasonally disconnected side channels, young-of-year salmonids in deep pools (≥100 cm) had greater survival than those in shallow pools (<100 cm). Densities of juvenile steelhead in all side channel types were similar to those in tributaries and were higher than in main-stem lateral margins. Juvenile Chinook Salmon densities were higher in side channels than in both tributary and main-stem lateral margins. Our results suggest that improving quality of pool habitat within seasonally disconnected side channels can result in improved survival for juvenile anadromous salmonids during the period of disconnection. Habitat improvement in these seasonally disconnected side channels should be recognized as a worthy restoration strategy, especially when full connectivity of side channels may not be a feasible target (e.g., through lack of water availability) or when full connectivity may present too high a risk (e.g., flooding, stream capture, bank destabilization).

Oak Ridge Reservation annual site environmental report for 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-10-01

The US Department of Energy currently oversees activities on the Oak Ridge Reservation (ORR), a government-owned, contractor-operated facility. Three sites compose the reservation: the Oak Ridge Y-12 Plant, Oak Ridge National Laboratory, and East Tennessee Technology Park (formerly the K-25 Site). The ORR was established in the early 1940s as part of the Manhattan Project, a secret undertaking that produced the materials for the first atomic bombs. The reservation`s role has evolved over the years, and it continues to adapt to meet the changing defense, energy, and research needs of the US. Both the work carried out for the warmore » effort and subsequent research, development, and production activities have produced (and continue to produce) radiological and hazardous wastes. This document contains a summary of environmental monitoring activities on the ORR and its surroundings. Environmental monitoring on the ORR consists of two major activities: effluent monitoring and environmental surveillance. Effluent monitoring involves the collection and analysis of samples or measurements of liquid and gaseous effluents prior to release into the environment; these measurements allow the quantification and official reporting of contaminants, assessment of radiation exposures to the public, and demonstration of compliance with applicable standards and permit requirements. Environmental surveillance consists of the collection and analysis of environmental samples from the site and its environs; this provides direct measurement of contaminants in air, water, groundwater, soil, foods, biota, and other media subsequent to effluent release into the environment. Environmental surveillance data verify ORR`s compliance status and, combined with data from effluent monitoring, allow the determination of chemical and radiation dose/exposure assessment of ORR operations and effects, if any, on the local environment.« less

Ultrathin Cobalt Oxide Overlayer Promotes Catalytic Activity of Cobalt Nitride for the Oxygen Reduction Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abroshan, Hadi; Bothra, Pallavi; Back, Seoin

Here, the oxygen reduction reaction (ORR) plays a crucial role in various energy devices such as proton-exchange membrane fuel cells (PEMFCs) and metal–air batteries. Owing to the scarcity of the current state-of-the-art Pt-based catalysts, cost-effective Pt-free materials such as transition metal nitrides and their derivatives have gained overwhelming interest as alternatives. In particular, cobalt nitride (CoN) has demonstrated a reasonably high ORR activity. However, the nature of its active phase still remains elusive. Here, we employ density functional theory calculations to study the surface reactivity of rocksalt (RS) and zincblend (ZB) cobalt nitride. The performances of the catalysts terminated bymore » the facets of (100), (110), and (111) are studied for the ORR. We demonstrate that the cobalt nitride surface is highly susceptible to oxidation under ORR conditions. The as-formed oxide overlayer on the facets of CoN RS(100) and CoN ZB(110) presents a significant promotional effect in reducing the ORR overpotential, thereby increasing the activity in comparison with those of the pure CoNs. The results of this work rationalize a number of experimental reports in the literature and disclose the nature of the active phase of cobalt nitrides for the ORR. Moreover, they offer guidelines for understanding the activity of other transition metal nitrides and designing efficient catalysts for future generation of PEMFCs.« less

Synergistically enhanced activity of nitrogen-doped carbon dots/graphene composites for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Liu, Hui; Zhao, Qingshan; Liu, Jingyan; Ma, Xiao; Rao, Yuan; Shao, Xiaodong; Li, Zhongtao; Wu, Wenting; Ning, Hui; Wu, Mingbo

2017-11-01

With rapid dissociative adsorption of oxygen, nitrogen-doped carbon nanomaterials have been demonstrated to be efficient alternative catalysts for oxygen reduction reaction (ORR) in fuel cells. Herein, we developed a mild hydrothermal strategy to construct nitrogen-doped carbon dots/graphene (NCDs-NG) composites towards ORR. Carbon dots (CDs) were derived from petroleum coke via acid oxidation while graphene oxide (GO) was obtained from graphite by modified Hummer's method. Graphene was employed as a conductive substrate to disperse CDs during hydrothermal reducing reaction while ammonia was utilized as N source to dope both graphene and CDs. The synergistic effects, i.e. CDs as pillars for graphene and catalytic sites for ORR, the high conductivity of graphene, the quick O2 adsorption on doped pyridinic nitrogen endow the NCDs-NG composites with enhanced ORR catalytic performance in alkaline electrolyte. The onset potential of -95 mV and kinetic current density of 12.7 mA cm-2 at -0.7 V (vs. Ag/AgCl) can be compared to those of the commercial 20 wt% Pt/C catalyst. The electron transfer number is about 3.9, revealing a four-electron pathway for ORR. The optimal NCDs-NG catalyst shows superior durability and methanol tolerance than 20 wt% Pt/C. This work demonstrates a feasible and effective strategy to prepare metal-free efficient ORR electrocatalysts for fuel cell applications.

Rational Design of N- S- Fe- Doped Nanoporous Carbon Catalysts from Covalent Triazine Framework for High Efficient ORR.

PubMed

Zhu, Yuanzhi; Chen, Xifan; Liu, Jing; Zhang, Junfeng; Xu, Danyun; Peng, Wenchao; Li, Yang; Zhang, Guoliang; Zhang, Fengbao; Fan, Xiaobin

2018-05-15

Porous organic polymers (POFs) are promising precursors for developing high performance transition metal-nitrogen-carbon (M-N/C) catalysts towards ORR. But the rational design of POFs precursors remain a great challenge, because of the elusive structural association between the sacrificial POFs and the final M-N/C catalysts. Based on covalent triazine frameworks (CTFs), we developed a series of sulfur-doped Fe-N/C catalysts by selecting six different aromatic nitriles as building blocks. A new mixed solvent of molten FeCl3 and S was used for CTF polymerization, which benefit the formation of Fe-Nx site and make the subsequent pyrolysis process more convenient. Comprehensive study on these CTF-derived catalysts shows their ORR activities are not directly dependent on the theoretical N/C ratio of the building block, but closely correlated to the ratios of the nitrile group to benzene ring (Nnitrile/Nbenzene) and geometries of the building blocks. The high ratios of the Nnitrile/Nbenzene are crucial for ORR activity of the final catalysts due to the formation of more N-doped microporous and Fe-Nx sites in pyrolysis possess. The optimized catalyst shows high ORR performances in acid and superior ORR activity to the Pt/C catalysts under alkaline conditions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrathin Cobalt Oxide Overlayer Promotes Catalytic Activity of Cobalt Nitride for the Oxygen Reduction Reaction

DOE PAGES

Abroshan, Hadi; Bothra, Pallavi; Back, Seoin; ...

2018-02-12

Here, the oxygen reduction reaction (ORR) plays a crucial role in various energy devices such as proton-exchange membrane fuel cells (PEMFCs) and metal–air batteries. Owing to the scarcity of the current state-of-the-art Pt-based catalysts, cost-effective Pt-free materials such as transition metal nitrides and their derivatives have gained overwhelming interest as alternatives. In particular, cobalt nitride (CoN) has demonstrated a reasonably high ORR activity. However, the nature of its active phase still remains elusive. Here, we employ density functional theory calculations to study the surface reactivity of rocksalt (RS) and zincblend (ZB) cobalt nitride. The performances of the catalysts terminated bymore » the facets of (100), (110), and (111) are studied for the ORR. We demonstrate that the cobalt nitride surface is highly susceptible to oxidation under ORR conditions. The as-formed oxide overlayer on the facets of CoN RS(100) and CoN ZB(110) presents a significant promotional effect in reducing the ORR overpotential, thereby increasing the activity in comparison with those of the pure CoNs. The results of this work rationalize a number of experimental reports in the literature and disclose the nature of the active phase of cobalt nitrides for the ORR. Moreover, they offer guidelines for understanding the activity of other transition metal nitrides and designing efficient catalysts for future generation of PEMFCs.« less

Polydopamine-Coated Manganese Complex/Graphene Nanocomposite for Enhanced Electrocatalytic Activity Towards Oxygen Reduction.

PubMed

Parnell, Charlette M; Chhetri, Bijay; Brandt, Andrew; Watanabe, Fumiya; Nima, Zeid A; Mudalige, Thilak K; Biris, Alexandru S; Ghosh, Anindya

2016-08-16

Platinum electrodes are commonly used electrocatalysts for oxygen reduction reactions (ORR) in fuel cells. However, this material is not economical due to its high cost and scarcity. We prepared an Mn(III) catalyst supported on graphene and further coated with polydopamine, resulting in superior ORR activity compared to the uncoated PDA structures. During ORR, a peak potential at 0.433 V was recorded, which is a significant shift compared to the uncoated material's -0.303 V (both versus SHE). All the materials reduced oxygen in a wide pH range via a four-electron pathway. Rotating disk electrode and rotating ring disk electrode studies of the polydopamine-coated material revealed ORR occurring via 4.14 and 4.00 electrons, respectively. A rate constant of 6.33 × 10(6) mol(-1)s(-1) was observed for the polydopamine-coated material-over 4.5 times greater than the uncoated nanocomposite and superior to those reported for similar carbon-supported metal catalysts. Simply integrating an inexpensive bioinspired polymer coating onto the Mn-graphene nanocomposite increased ORR performance significantly, with a peak potential shift of over +730 mV. This indicates that the material can reduce oxygen at a higher rate but with lower energy usage, revealing its excellent potential as an ORR electrocatalyst in fuel cells.

Surface profile control of FeNiPt/Pt core/shell nanowires for oxygen reduction reaction

DOE PAGES

Zhu, Huiyuan; Zhang, Sen; Su, Dong; ...

2015-03-18

The ever-increasing energy demand requires renewable energy schemes with low environmental impacts. Electrochemical energy conversion devices, such as fuel cells, combine fuel oxidization and oxygen reduction reactions and have been studied extensively for renewable energy applications. However, their energy conversion efficiency is often limited by kinetically sluggish chemical conversion reactions, especially oxygen reduction reaction (ORR). [1-5] To date, extensive efforts have been put into developing efficient ORR catalysts with controls on catalyst sizes, compositions, shapes and structures. [6-12] Recently, Pt-based catalysts with core/shell and one-dimensional nanowire (NW) morphologies were found to be promising to further enhance ORR catalysis.more » With the core/shell structure, the ORR catalysis of a nanoparticle (NP) catalyst can be tuned by both electronic and geometric effects at the core/shell interface. [10,13,14] With the NW structure, the catalyst interaction with the conductive support can be enhanced to facilitate electron transfer between the support and the NW catalyst and to promote ORR. [11,15,16]« less

Coupled s-p-d Exchange in Facet-Controlled Pd 3 Pb Tripods Enhances Oxygen Reduction Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bu, Lingzheng; Shao, Qi; Pi, Yecan

Efficient oxygen reduction reaction (ORR) catalysts are the key in developing high-performance fuel cells. Palladium (Pd) is a promising catalyst system for ORR with its potential to replace platinum (Pt), however it usually exhibits lower activity than Pt. Herein, we report a class of ordered Pd3Pb tripods (TPs) with dominated {110} facets that show extremely high ORR performance in alkaline medium. Totally different from the well-known knowledge that excellent ORR activity of Pt catalyst is caused by its partially-filled d-orbital, our first principle calculations suggest that the strong charge exchange between Pd-4d and Pb-(sp) orbitals on Pd3Pb TPs {110} facetmore » results in the Pd-Pb local bonding unit with the orbital configuration similar to Pt. Consequently, the Pd3Pb TPs exhibit much higher ORR activities than commercial Pt/C and commercial Pd/C. The Pd3Pb TPs are rather endurable and sustain over 20,000 potential cycles with negligible structural and compositional changes.« less

Coupled s-p-d Exchange in Facet-Controlled Pd 3 Pb Tripods Enhances Oxygen Reduction Catalysis

DOE PAGES

Bu, Lingzheng; Shao, Qi; Pi, Yecan; ...

2018-02-01

Efficient oxygen reduction reaction (ORR) catalysts are the key in developing high-performance fuel cells. Palladium (Pd) is a promising catalyst system for ORR with its potential to replace platinum (Pt), however it usually exhibits lower activity than Pt. Herein, we report a class of ordered Pd3Pb tripods (TPs) with dominated {110} facets that show extremely high ORR performance in alkaline medium. Totally different from the well-known knowledge that excellent ORR activity of Pt catalyst is caused by its partially-filled d-orbital, our first principle calculations suggest that the strong charge exchange between Pd-4d and Pb-(sp) orbitals on Pd3Pb TPs {110} facetmore » results in the Pd-Pb local bonding unit with the orbital configuration similar to Pt. Consequently, the Pd3Pb TPs exhibit much higher ORR activities than commercial Pt/C and commercial Pd/C. The Pd3Pb TPs are rather endurable and sustain over 20,000 potential cycles with negligible structural and compositional changes.« less

A Nanopore-Structured Nitrogen-Doped Biocarbon Electrocatalyst for Oxygen Reduction from Two-Step Carbonization of Lemna minor Biomass.

PubMed

Guo, Chaozhong; Li, Zhongbin; Niu, Lidan; Liao, Wenli; Sun, Lingtao; Wen, Bixia; Nie, Yunqing; Cheng, Jing; Chen, Changguo

2016-12-01

So far, the development of highly active and stable carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace commercial Pt/C catalyst is a hot topic. In this study, a new nanoporous nitrogen-doped carbon material was facilely designed by two-step pyrolysis of the renewable Lemna minor enriched in crude protein under a nitrogen atmosphere. Electrochemical measurements show that the onset potential for ORR on this carbon material is around 0.93 V (versus reversible hydrogen electrode), slightly lower than that on the Pt/C catalyst, but its cycling stability is higher compared to the Pt/C catalyst in an alkaline medium. Besides, the ORR at this catalyst approaches to a four-electron transfer pathway. The obtained ORR performance can be basically attributed to the formation of high contents of pyridinic and graphitic nitrogen atoms inside this catalyst. Thus, this work opens up the path in the ORR catalysis for the design of nitrogen-doped carbon materials utilizing aquatic plants as starting precursors.

Enhanced vacuum arc vapor deposition electrode

NASA Technical Reports Server (NTRS)

Weeks, Jack L. (Inventor); Todd, Douglas M. (Inventor)

1999-01-01

A process for forming a thin metal coating on a substrate wherein a gas stream heated by an electrical current impinges on a metallic target in a vacuum chamber to form a molten pool of the metal and then vaporize a portion of the pool, with the source of the heated gas stream being on one side of the target and the substrate being on the other side of the target such that most of the metallic vapor from the target is directed at the substrate.

Cabozantinib Versus Sunitinib As Initial Targeted Therapy for Patients With Metastatic Renal Cell Carcinoma of Poor or Intermediate Risk: The Alliance A031203 CABOSUN Trial

PubMed Central

Halabi, Susan; Sanford, Ben L.; Hahn, Olwen; Michaelson, M. Dror; Walsh, Meghara K.; Feldman, Darren R.; Olencki, Thomas; Picus, Joel; Small, Eric J.; Dakhil, Shaker; George, Daniel J.; Morris, Michael J.

2017-01-01

Purpose Cabozantinib is an oral potent inhibitor of vascular endothelial growth factor receptor 2, MET, and AXL and is a standard second-line therapy for metastatic renal cell carcinoma (mRCC). This randomized phase II multicenter trial evaluated cabozantinib compared with sunitinib as first-line therapy in patients with mRCC. Patients and Methods Eligible patients had untreated clear cell mRCC and Eastern Cooperative Oncology Group performance status of 0 to 2 and were intermediate or poor risk per International Metastatic Renal Cell Carcinoma Database Consortium criteria. Patients were randomly assigned at a one-to-one ratio to cabozantinib (60 mg once per day) or sunitinib (50 mg once per day; 4 weeks on, 2 weeks off). Progression-free survival (PFS) was the primary end point. Objective response rate (ORR), overall survival, and safety were secondary end points. Results From July 2013 to April 2015, 157 patients were randomly assigned (cabozantinib, n = 79; sunitinib, n = 78). Compared with sunitinib, cabozantinib treatment significantly increased median PFS (8.2 v 5.6 months) and was associated with a 34% reduction in rate of progression or death (adjusted hazard ratio, 0.66; 95% CI, 0.46 to 0.95; one-sided P = .012). ORR was 33% (95% CI, 23% to 44%) for cabozantinib versus 12% (95% CI, 5.4% to 21%) for sunitinib. All-causality grade 3 or 4 adverse events were 67% for cabozantinib and 68% for sunitinib and included diarrhea (cabozantinib, 10% v sunitinib, 11%), fatigue (6% v 15%), hypertension (28% v 22%), palmar-plantar erythrodysesthesia (8% v 4%), and hematologic adverse events (3% v 22%). Conclusion Cabozantinib demonstrated a significant clinical benefit in PFS and ORR over standard-of-care sunitinib as first-line therapy in patients with intermediate- or poor-risk mRCC. PMID:28199818

Oak Ridge Reservation Physical Characteristics and Natural Resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parr, P.D.; Hughes, J.F.

The topography, geology, hydrology, vegetation, and wildlife of the Oak Ridge Reservation (ORR) provide a complex and intricate array of resources that directly impact land stewardship and use decisions (Fig. 1). The purpose of this document is to consolidate general information regarding the natural resources and physical characteristics of the ORR. The ORR, encompassing 33,114 acres (13,401 ha) of federally owned land and three Department of Energy (DOE) installations, is located in Roane and Anderson Counties in east Tennessee, mostly within the corporate limits of the city of Oak Ridge and southwest of the population center of Oak Ridge. Themore » ORR is bordered on the north and east by the population center of the city of Oak Ridge and on the south and west by the Clinch River/Melton Hill Lake impoundment. All areas of the ORR are relatively pristine when compared with the surrounding region, especially in the Valley and Ridge Physiographic Province (Fig. 2). From the air, the ORR is clearly a large and nearly continuous island of forest within a landscape that is fragmented by urban development and agriculture. Satellite imagery from 2006 was used to develop a land-use/land-cover cover map of the ORR and surrounding lands (Fig. 3). Following the acquisition of the land comprising the ORR in the early 1940s, much of the Reservation served as a buffer for the three primary facilities: the X-10 nuclear research facility (now known as the Oak Ridge National Laboratory [ORNL]), the first uranium enrichment facility or Y-12 (now known as the Y-12 National Security Complex [Y-12 Complex]), and a gaseous diffusion enrichment facility (now known as the East Tennessee Technology Park [ETTP]). Over the past 60 years, this relatively undisturbed area has evolved into a rich and diverse eastern deciduous forest ecosystem of streams and reservoirs, hardwood forests, and extensive upland mixed forests. The combination of a large land area with complex physical characteristics and diverse natural resources has provided a critical foundation for supporting DOE's environmental research mission, as well as the area in which to build leading-edge facilities.« less

[Efficacy and side-effects of docetaxel combined with cisplatin on the treatment of local advanced esophageal cancer with concomitant radiation therapy].

PubMed

Zhang, Ting-rong; Zhao, Tao; Xu, Xin; Gu, Xiao-wei; Pan, Yu-kai

2010-10-01

To investigate the therapeutical effect and side-effect of docetaxel combined with cisplatin (DDP) on the treatment of local advanced esophageal cancer with concomitant radiation therapy. Ninety patients with LOCAL advanced esophageal squamous cell carcinoma were divided into two groups: (DDP + 5-Fu) group and (docetaxel + DDP) group. Chemotherapy was carried out every 4 weeks for a total of 4 courses. The radiation dose was 50.4 Gy/28FX. The median survival time of patients in the (DDP + 5-Fu) group was 16 months and that in (docetaxel + DDP) group was 21 months (P = 0.0278). The 3-year survival rate in the (docetaxel + DDP) group was obviously higher than that in the (DDP + 5-Fu) group (23.9% vs. 12.1%). The ORR in (docetaxel + DDP) group (84.5%) was significantly higher than that in the (DDP + 5-Fu) group (71.1%) (P = 0.025). No significant differences were observed in the incidence of side-effects in the two groups. The conventional dose chemotherapy of docetaxel + DDP with concomitant radiation therapy showed a better partial remission rate and long-term survival rate for the treatment of local advanced esophageal cancer than the traditional chemotherapy (DDP + 5-Fu) with concomitant radiation therapy and the side-effects are not increased.

A&M. TAN607. Section views of hot shop. Section E shows ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

A&M. TAN-607. Section views of hot shop. Section E shows equipment areas along rear wall. Section F shows storage pool cut along east/west line. Roof trusses, shelves along sides of pool, drain, roof trusses, shelves along sides of pool, drain, and sump. Section G cuts along north/south to show centerline of turntables, manipulator arms, O-man bridge, crane bridge. Referent drawing is ID-33-E-158 above. Ralph M. Parsons 902-3-ANP-607-A 107. Date: December 1952, but as-built in 1982. Approved by INEEL Classification Office for public release. INEEL index code no. 034-0607-00-693-106759 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Novel nanowire-structured polypyrrole-cobalt composite as efficient catalyst for oxygen reduction reaction

PubMed Central

Yuan, Xianxia; Li, Lin; Ma, Zhong; Yu, Xuebin; Wen, Xiufang; Ma, Zi-Feng; Zhang, Lei; Wilkinson, David P.; Zhang, Jiujun

2016-01-01

A novel nanowire-structured polypyrrole-cobalt composite, PPy-CTAB-Co, is successfully synthesized with a surfactant of cetyltrimethylammounium bromide (CTAB). As an electro-catalyst towards oxygen reduction reaction (ORR) in alkaline media, this PPy-CTAB-Co demonstrates a superior ORR performance when compared to that of granular PPy-Co catalyst and also a much better durability than the commercial 20 wt% Pt/C catalyst. Physiochemical characterization indicates that the enhanced ORR performance of the nanowire PPy-CTAB-Co can be attributed to the high quantity of Co-pyridinic-N groups as ORR active sites and its large specific surface area which allows to expose more active sites for facilitating oxygen reduction reaction. It is expected this PPy-CTAB-Co would be a good candidate for alkaline fuel cell cathode catalyst. PMID:26860889

A philosophical analysis of David Orr's theory of ecological literacy: biophilia, ecojustice and moral education in school learning communities

NASA Astrophysics Data System (ADS)

Mitchell, Debra B.; Mueller, Michael P.

2011-03-01

In his writings, David Orr claims that the US is in an "ecological crisis" and that this stems from a crisis of education. He outlines a theory of ecological literacy, a mode by which we better learn the ecology of the Earth and live in a sustainable manner. While emphasizing a shock doctrine, the diagnosis of "crisis" may be correct, but it is short-lived for children and adults of the world. In this philosophical analysis of Orr's theory, it is argued that we move beyond the perspective of crisis. By extending Orr's ecological literacy with biophilia and ecojustice and by recognizing the importance of experience-in-learning, science education is envisioned to incorporate values and morals within a longer term ideology of educational reform.

Remedial investigation/feasibility study report for Lower Watts Bar Reservoir Operable Unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-03-01

This document is the combined Remedial Investigation and Feasibility Study Report for the lower Watts Bar Reservoir (LWBR) Operable Unit (OU). The LWBR is located in Roane, Rhea, and Meigs counties, Tennessee, and consists of Watts Bar Reservoir downstream of the Clinch river. This area has received hazardous substances released over a period of 50 years from the US Department of Energy`s Oak Ridge Reservation (ORR), a National Priority List site established under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). As required by this law, the ORR and all off-site areas that have received contaminants, including LWBR, mustmore » be investigated to determine the risk to human health and the environment resulting from these releases, the need for any remedial action to reduce these risks, and the remedial actions that are most feasible for implementation in this OU. Contaminants from the ORR are primarily transported to the LWBR via the Clinch River. There is little data regarding the quantities of most contaminants potentially released from the ORR to the Clinch River, particularly for the early years of ORR operations. Estimates of the quantities released during this period are available for most radionuclides and some inorganic contaminants, indicating that releases 30 to 50 years ago were much higher than today. Since the early 1970s, the release of potential contaminants has been monitored for compliance with environmental law and reported in the annual environmental monitoring reports for the ORR.« less

Status Report on the Geology of the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatcher, R.D., Jr.

1992-01-01

This report provides an introduction to the present state of knowledge of the geology of the Oak Ridge Reservation (ORR) and a cursory introduction to the hydrogeology. A detailed reported on hydrogeology is being produced in parallel to this one. An important element of this work is the construction of a modern detailed geologic map of the ORR containing subdivisions of all mappable rock units and displaying mesoscopic structural data. Understanding the geologic framework of the ORR is essential to many current and proposed activities related to land-use planning, waste management, environmental restoration, and waste remediation. This interim report ismore » the result of cooperation between geologists in two Oak Ridge National Laboratory (ORNL) divisions, Environmental Sciences and Energy, and is a major part of one doctoral dissertation in the Department of Geological Sciences at The University of Tennessee--Knoxville. Major long-term goals of geologic investigations in the ORR are to determine what interrelationships exist between fractures systems in individual rock or tectonic units and the fluid flow regimes, to understand how regional and local geology can be used to help predict groundwater movement, and to formulate a structural-hydrologic model that for the first time would enable prediction of the movement of groundwater and other subsurface fluids in the ORR. Understanding the stratigraphic and structural framework and how it controls fluid flow at depth should be the first step in developing a model for groundwater movement. Development of a state-of-the-art geologic and geophysical framework for the ORR is therefore essential for formulating an integrated structural-hydrologic model. This report is also intended to convey the present state of knowledge of the geologic and geohydrologic framework of the ORR and vicinity and to present some of the data that establish the need for additional geologic mapping and geohydrologic studies. An additional intended use should be for guided field trips or for self-guided tours by geoscientists. This guidebook provides the following: (1) the geologic setting of the ORR in the context of the Valley and Ridge province, (2) general descriptions of the major stratigraphic units mapped on the surface or recognized in drill holes, (3) a general description of geologic structure in the Oak Ridge area, (4) a discussion of the relationship between geology and geohydrology, and (5) descriptions of localities where each major stratigraphic unit may be observed in or near the ORR. Appendices contain field trip stop descriptions and data on soils.« less

Oxaliplatin-Based Doublets Versus Cisplatin or Carboplatin-Based Doublets in the First-Line Treatment of Advanced Nonsmall Cell Lung Cancer.

PubMed

Yu, Jing; Xiao, Jing; Yang, Yifan; Cao, Bangwei

2015-07-01

The efficacy and toxicity of oxaliplatin-based versus carboplatin/cisplatin-based doublets in patients with previously untreated nonsmall cell lung cancer (NSCLC) have been compared.We searched published randomized controlled trials of oxaliplatin-based or carboplatin/cisplatin-based medications for NSCLC. A fixed effect model was used to analyze outcomes which were expressed as the hazard ratio for overall survival (OS) and time-to-progression (TTP), relative risk, overall response rate (ORR), disease control rate (DCR), 1-year survival, and the odds ratios for toxicity were pooled.Eight studies involving 1047 patients were included. ORR tended to favor carboplatin/cisplatin but the effect was not significantly different compared with oxaliplatin doublets (P = 0.05). The effects of OS, TTP, DCR, and 1-year survival between the 2 regimens were comparable. Oxaliplatin doublets caused less grade 3/4 leukocytopenia and neutropenia. Grades 3 to 4 nonhematological toxicities and grades 3 to 4 hematological toxicities showed little difference between oxaliplatin doublets and carboplatin/cisplatin doublets.Meta-analysis shows that the efficacy of oxaliplatin doublets is similar to that of other currently used platinum doublets. The lack of significant differences in the statistic analysis does not preclude genuine differences in clinical efficacy, because higher diversities between the studies covered differences between the 2 groups in each study. Oxaliplatin combined with a third-generation agent should be considered for use as alternative chemotherapy in patients who cannot tolerate conventional platinum-based regimens because the toxicity profile is much more favorable.

Degradation of DEET and Caffeine under UV/Chlorine and Simulated Sunlight/Chlorine Conditions.

PubMed

Sun, Peizhe; Lee, Wan-Ning; Zhang, Ruochun; Huang, Ching-Hua

2016-12-20

Photoactivation of aqueous chlorine could promote degradation of chlorine-resistant and photochemically stable chemicals accumulated in swimming pools. This study investigated the degradation of two such chemicals, N,N-diethyl-3-methylbenzamide (DEET) and caffeine, by low pressure ultraviolet (UV) light and simulated sunlight (SS) activated free chlorine (FC) in different water matrices. Both DEET and caffeine were rapidly degraded by UV/FC and SS/FC but exhibited different kinetic behaviors. The degradation of DEET followed pseudo-first-order kinetics, whereas the degradation of caffeine accelerated with reaction. Mechanistic study revealed that, under UV/FC, ·OH and Cl· were responsible for degradation of DEET, whereas ClO· related reactive species (ClOrrs), generated by the reaction between FC and ·OH/Cl·, played a major role in addition to ·OH and Cl· in degrading caffeine. Reaction rate constants of DEET and caffeine with the respective radical species were estimated. The imidazole moiety of caffeine was critical for the special reactivity with ClOrrs. Water matrix such as pH had a stronger impact on the UV/FC process than the SS/FC process. In saltwater matrix under UV/FC and SS/FC, the degradation of DEET was significantly inhibited, but the degradation of caffeine was much faster than that in nonsalty solutions. The interaction between Br - and Cl - may play an important role in the degradation of caffeine by UV/FC in saltwater. Reaction product analysis showed similar product patterns by UV/FC and SS/FC and minimal formation of chlorinated intermediates and disinfection byproducts.

Oxygen reduction kinetics on Pt monolayer shell highly affected by the structure of bimetallic AuNi cores

DOE PAGES

Chen, Guangyu; Kuttiyiel, Kurian A.; Su, Dong; ...

2016-07-12

Here, we describe pronounced effects of structural changes of the AuNi cores on the oxygen reduction reaction (ORR) activity of a Pt monolayer shell. The study of alloyed AuNi nanoparticles compared with AuNi core–shell structured nanoparticles revealed configurations having different electronic and electrochemical properties. Controlled alloying of Au with Ni was essential to tune the electronic properties of Au interacting with the Pt monolayer shell to achieve suitable adsorption of O 2 on Pt for expediting the ORR. The alloyed AuNi nanoparticles made the Pt shell more catalytically active for the ORR than the core–shell structured AuNi nanoparticles. The Ptmore » monolayer supported on the alloyed AuNi nanoparticles showed the Pt mass and specific activities as high as 1.52 A mg –1 and 1.18 mA cm –2, respectively, with almost no loss over 5 000 cycles of stability test. This high ORR activity is ascribed to the role of nonspecific steric configuration of Ni atoms changing the electronic properties of the alloy that affect the oxygen and water interaction with the Pt shell and facilitate increased ORR kinetics.« less

From two-dimension to one-dimension: the curvature effect of silicon-doped graphene and carbon nanotubes for oxygen reduction reaction.

PubMed

Zhang, Peng; Hou, Xiuli; Mi, Jianli; He, Yanqiong; Lin, Lin; Jiang, Qing; Dong, Mingdong

2014-09-07

For the goal of practical industrial development of fuel cells, inexpensive, sustainable, and highly efficient electrocatalysts for oxygen reduction reactions (ORR) are highly desirable alternatives to platinum (Pt) and other rare metals. In this work, based on density functional theory, silicon (Si)-doped carbon nanotubes (CNTs) and graphene as metal-free, low cost, and high-performance electrocatalysts for ORR are studied systematically. It is found that the curvature effect plays an important role in the adsorption and reduction of oxygen. The adsorption of O2 becomes weaker as the curvature varies from positive values (outside CNTs) to negative values (inside CNTs). The free energy change of the rate-determining step of ORR on the concave inner surface of Si-doped CNTs is smaller than that on the counterpart of Si-doped graphene, while that on the convex outer surface of Si-doped CNTs is larger than that on Si-doped graphene. Uncovering this new ORR mechanism on silicon-doped carbon electrodes is significant as the same principle could be applied to the development of various other metal-free efficient ORR catalysts for fuel cell applications.

3,4-Ethylenedioxythiophene functionalized graphene with palladium nanoparticles for enhanced electrocatalytic oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Choe, Ju Eun; Ahmed, Mohammad Shamsuddin; Jeon, Seungwon

2015-05-01

Poly(3,4-ethylenedioxythiophene) functionalized graphene with palladium nanoparticles (denoted as Pd/PEDOT/rGO) has been synthesized for electrochemical oxygen reduction reaction (ORR) in alkaline solution. The structural features of catalyst are characterized by scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The TEM images suggest a well dispersed PdNPs onto PEDOT/rGO film. The ORR activity of Pd/PEDOT/rGO has been investigated via cyclic voltammetry (CV), rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) techniques in 0.1 M KOH aqueous solution. Comparative CV analysis suggests a general approach of intermolecular charge-transfer in between graphene sheet and PdNPs via PEDOT which leads to the better PdNPs dispersion and subsequently superior ORR kinetics. The results from ORR measurements show that Pd/PEDOT/rGO has remarkable electrocatalytic activity and stability compared to Pd/rGO and state-of-the-art Pt/C. The Koutecky-Levich and Tafel analysis suggest that the proposed main path in the ORR mechanism has direct four-electron transfer process with faster transfer kinetic rate on the Pd/PEDOT/rGO.

Porous carbon supported Fe-N-C composite as an efficient electrocatalyst for oxygen reduction reaction in alkaline and acidic media

NASA Astrophysics Data System (ADS)

Liu, Baichen; Huang, Binbin; Lin, Cheng; Ye, Jianshan; Ouyang, Liuzhang

2017-07-01

In recent years, non-precious metal electrocatalysts for oxygen reduction reaction (ORR) have attracted tremendous attention due to their high catalytic activity, long-term stability and excellent methanol tolerance. Herein, the porous carbon supported Fe-N-C catalysts for ORR were synthesized by direct pyrolysis of ferric chloride, 6-Chloropyridazin-3-amine and carbon black. Variation of pyrolysis temperature during the synthesis process leads to the difference in ORR catalytic activity. High pyrolysis temperature is beneficial to the formation of the "N-Fe" active sites and high electrical conductivity, but the excessive temperature will cause the decomposition of nitrogen-containing active sites, which are revealed by Raman, TGA and XPS. A series of synthesis and characterization experiments with/without nitrogen or iron in carbon black indicate that the coordination of iron and nitrogen plays a crucial role in achieving excellent ORR performances. Electrochemical test results show that the catalyst pyrolyzed at 800 °C (Fe-N-C-800) exhibits excellent ORR catalytic activity, better methanol tolerance and higher stability compared with commercial Pt/C catalyst in both alkaline and acidic conditions.

Co- and defect-rich carbon nanofiber films as a highly efficient electrocatalyst for oxygen reduction

NASA Astrophysics Data System (ADS)

Kim, Il To; Song, Myeong Jun; Shin, Seoyoon; Shin, Moo Whan

2018-03-01

Many efforts are continuously devoted to developing high-efficiency, low-cost, and highly scalable oxygen reduction reaction (ORR) electrocatalysts to replace precious metal catalysts. Herein, we successfully synthesize Co- and defect-rich carbon nanofibers (CNFs) using an efficient heat treatment approach involving the pyrolysis of electrospun fibers at 370 °C under air. The heat treatment process produces Co-decorated CNFs with a high Co mass ratio, enriched pyridinic N, Co-pyridinic Nx clusters, and defect-rich carbon structures. The synergistic effects from composition and structural changes in the designed material increase the number of catalytically active sites for the ORR in an alkaline solution. The prepared Co- and defect-rich CNFs exhibit excellent ORR activities with a high ORR onset potential (0.954 V vs. RHE), a large reduction current density (4.426 mA cm-2 at 0.40 V), and a nearly four-electron pathway. The catalyst also exhibits a better long-term durability than commercial Pt/C catalysts. This study provides a novel hybrid material as an efficient ORR catalyst and important insight into the design strategy for CNF-based hybrid materials as electrochemical electrodes.

78 FR 32666 - Submission for OMB Review; Comment Request

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2013-05-31

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Robust Platinum-Based Electrocatalysts for Fuel Cell Applications

NASA Astrophysics Data System (ADS)

Coleman, Eric James

Polymer electrolyte fuel cells (PEMFCs) are energy conversion devices that exploit the energetics of the reaction between hydrogen fuel and O 2 to generate electricity with water as the only byproduct. PEMFCs have attracted substantial attention due to their high conversion efficiency, high energy density, and low carbon footprint. However, PEMFC performance is hindered by the high activation barrier and slow reaction rates at the cathode where O2 undergoes an overall 4-electron reduction to water. The most efficient oxygen reduction reaction (ORR) catalyst materials to date are Pt group metals due to their high catalytic activity and stability in a wide range of operating conditions. Before fuel cells can become economically viable, efforts must be taken to decrease Pt content while maintaining a high level of ORR activity. This work describes the design and synthesis of a Pt-Cu electrocatalyst with ORR activity exceeding that of polycrystalline Pt. Production of this novel catalyst is quite simple and begins with synthesis of a porous Cu substrate, formed by etching Al from a Cu-Al alloy. The porous Cu substrate is then coated with a Pt layer via a spontaneous electrochemical process known as galvanic replacement. The Pt layer enhances the ORR activity (as measured by a rotating ring-disk electrode (RRDE)) and acts as a barrier towards corrosion of the Cu understructure. Growth of the Pt layer can be manipulated by time, temperature, concentration of Pt precursor, and convection rate during galvanic replacement. Data from analytical and electrochemical techniques confirm multiple Pt loadings have been achieved via the galvanic replacement process. The boost in ORR activity for the PtCu catalyst was determined to be a result of its lower affinity towards (site-blocking) OH adsorption. A unique catalyst degradation study explains the mechanism of initial catalyst ORR deactivation for both monometallic and bimetallic Pt-based catalysts. Finally, a rigorous and pioneering examination of how Pt surface passivation affects ORR dynamics is presented.

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Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

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Heavily Graphitic-Nitrogen Self-doped High-porosity Carbon for the Electrocatalysis of Oxygen Reduction Reaction

NASA Astrophysics Data System (ADS)

Feng, Tong; Liao, Wenli; Li, Zhongbin; Sun, Lingtao; Shi, Dongping; Guo, Chaozhong; Huang, Yu; Wang, Yi; Cheng, Jing; Li, Yanrong; Diao, Qizhi

2017-11-01

Large-scale production of active and stable porous carbon catalysts for oxygen reduction reaction (ORR) from protein-rich biomass became a hot topic in fuel cell technology. Here, we report a facile strategy for synthesis of nitrogen-doped porous nanocarbons by means of a simple two-step pyrolysis process combined with the activation of zinc chloride and acid-treatment process, in which kidney bean via low-temperature carbonization was preferentially adopted as the only carbon-nitrogen sources. The results show that this carbon material exhibits excellent ORR electrocatalytic activity, and higher durability and methanol-tolerant property compared to the state-of-the-art Pt/C catalyst for the ORR, which can be mainly attributed to high graphitic-nitrogen content, high specific surface area, and porous characteristics. Our results can encourage the synthesis of high-performance carbon-based ORR electrocatalysts derived from widely-existed natural biomass.

Homogenous Electrocatalytic Oxygen Reduction Rates Correlate with Reaction Overpotential in Acidic Organic Solutions

PubMed Central

2016-01-01

Improved electrocatalysts for the oxygen reduction reaction (ORR) are critical for the advancement of fuel cell technologies. Herein, we report a series of 11 soluble iron porphyrin ORR electrocatalysts that possess turnover frequencies (TOFs) from 3 s–1 to an unprecedented value of 2.2 × 106 s–1. These TOFs correlate with the ORR overpotential, which can be modulated by changing the E1/2 of the catalyst using different ancillary ligands, by changing the solvent and solution acidity, and by changing the catalyst’s protonation state. The overpotential is well-defined for these homogeneous electrocatalysts by the E1/2 of the catalyst and the proton activity of the solution. This is the first such correlation for homogeneous ORR electrocatalysis, and it demonstrates that the remarkably fast TOFs are a consequence of high overpotential. The correlation with overpotential is surprising since the turnover limiting steps involve oxygen binding and protonation, as opposed to turnover limiting electron transfer commonly found in Tafel analysis of heterogeneous ORR materials. Computational studies show that the free energies for oxygen binding to the catalyst and for protonation of the superoxide complex are in general linearly related to the catalyst E1/2, and that this is the origin of the overpotential correlations. This analysis thus provides detailed understanding of the ORR barriers. The best catalysts involve partial decoupling of the influence of the second coordination sphere from the properties of the metal center, which is suggested as new molecular design strategy to avoid the limitations of the traditional scaling relationships for these catalysts. PMID:27924314

Identification of catalytic sites for oxygen reduction and oxygen evolution in N-doped graphene materials: Development of highly efficient metal-free bifunctional electrocatalyst

PubMed Central

Yang, Hong Bin; Miao, Jianwei; Hung, Sung-Fu; Chen, Jiazang; Tao, Hua Bing; Wang, Xizu; Zhang, Liping; Chen, Rong; Gao, Jiajian; Chen, Hao Ming; Dai, Liming; Liu, Bin

2016-01-01

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are critical to renewable energy conversion and storage technologies. Heteroatom-doped carbon nanomaterials have been reported to be efficient metal-free electrocatalysts for ORR in fuel cells for energy conversion, as well as ORR and OER in metal-air batteries for energy storage. We reported that metal-free three-dimensional (3D) graphene nanoribbon networks (N-GRW) doped with nitrogen exhibited superb bifunctional electrocatalytic activities for both ORR and OER, with an excellent stability in alkaline electrolytes (for example, KOH). For the first time, it was experimentally demonstrated that the electron-donating quaternary N sites were responsible for ORR, whereas the electron-withdrawing pyridinic N moieties in N-GRW served as active sites for OER. The unique 3D nanoarchitecture provided a high density of the ORR and OER active sites and facilitated the electrolyte and electron transports. As a result, the as-prepared N-GRW holds great potential as a low-cost, highly efficient air cathode in rechargeable metal-air batteries. Rechargeable zinc-air batteries with the N-GRW air electrode in a two-electrode configuration exhibited an open-circuit voltage of 1.46 V, a specific capacity of 873 mAh g−1, and a peak power density of 65 mW cm−2, which could be continuously charged and discharged with an excellent cycling stability. Our work should open up new avenues for the development of various carbon-based metal-free bifunctional electrocatalysts of practical significance. PMID:27152333

MO-Co@N-Doped Carbon (M = Zn or Co): Vital Roles of Inactive Zn and Highly Efficient Activity toward Oxygen Reduction/Evolution Reactions for Rechargeable Zn-Air Battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Biaohua; He, Xiaobo; Yin, Fengxiang

A highly efficient bifunctional oxygen catalyst is required for practical applications of fuel cells and metal-air batteries, as oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are their core electrode reactions. Here, the MO-Co@ N-doped carbon (NC, M = Zn or Co) is developed as a highly active ORR/OER bifunctional catalyst via pyrolysis of a bimetal metal-organic framework containing Zn and Co, i.e., precursor (CoZn). The vital roles of inactive Zn in developing highly active bifunctional oxygen catalysts are unraveled. When the precursors include Zn, the surface contents of pyridinic N for ORR and the surface contents of Co-N-xmore » and Co3+/Co2+ ratios for OER are enhanced, while the high specific surface areas, high porosity, and high electrochemical active surface areas are also achieved. Furthermore, the synergistic effects between Zn-based and Co-based species can promote the well growth of multiwalled carbon nanotubes (MWCNTs) at high pyrolysis temperatures (>= 700 degrees C), which is favorable for charge transfer. The optimized CoZn-NC-700 shows the highly bifunctional ORR/OER activity and the excellent durability during the ORR/OER processes, even better than 20 wt% Pt/C (for ORR) and IrO2 (for OER). CoZn-NC-700 also exhibits the prominent Zn-air battery performance and even outperforms the mixture of 20 wt% Pt/C and IrO2.« less

77 FR 74851 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-18

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Hierarchically porous Fe-N-C derived from covalent-organic materials as a highly efficient electrocatalyst for oxygen reduction

NASA Astrophysics Data System (ADS)

Zuo, Quan; Zhao, Pingping; Luo, Wei; Cheng, Gongzhen

2016-07-01

Developing high-performance non-precious catalysts to replace platinum as oxygen reduction reaction (ORR) catalysts is still a big scientific and technological challenge. Herein, we report a simple method for the synthesis of a FeNC catalyst with a 3D hierarchically micro/meso/macro porous network and high surface area through a simple carbonization method by taking the advantages of a high specific surface area and diverse pore dimensions in 3D porous covalent-organic material. The resulting FeNC-900 electrocatalyst with improved reactant/electrolyte transport and sufficient active site exposure, exhibits outstanding ORR activity with a half-wave potential of 0.878 V, ca. 40 mV more positive than Pt/C for ORR in alkaline solution, and a half-wave potential of 0.72 V, which is comparable to that of Pt/C in acidic solution. In particular, the resulting FeNC-900 exhibits a much higher stability and methanol tolerance than those of Pt/C, which makes it among the best non-precious catalysts ever reported for ORR.Developing high-performance non-precious catalysts to replace platinum as oxygen reduction reaction (ORR) catalysts is still a big scientific and technological challenge. Herein, we report a simple method for the synthesis of a FeNC catalyst with a 3D hierarchically micro/meso/macro porous network and high surface area through a simple carbonization method by taking the advantages of a high specific surface area and diverse pore dimensions in 3D porous covalent-organic material. The resulting FeNC-900 electrocatalyst with improved reactant/electrolyte transport and sufficient active site exposure, exhibits outstanding ORR activity with a half-wave potential of 0.878 V, ca. 40 mV more positive than Pt/C for ORR in alkaline solution, and a half-wave potential of 0.72 V, which is comparable to that of Pt/C in acidic solution. In particular, the resulting FeNC-900 exhibits a much higher stability and methanol tolerance than those of Pt/C, which makes it among the best non-precious catalysts ever reported for ORR. Electronic supplementary information (ESI) available: Fig. S1-S12 and Tables S1 and S2. See DOI: 10.1039/c6nr03273g

Charting the relationship between phase type-surface area-interactions between the constituent atoms and oxygen reduction activity of Pd–Cu nanocatalysts inside fuel cells by in operando high-energy X-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maswadeh, Yazan; Shan, Shiyao; Prasai, Binay

The activity and stability of nanoalloy catalysts for chemical reactions driving devices for clean energy conversion, in particular the oxygen reduction reaction (ORR), depend critically on optimizing major structural characteristics of the nanoalloys, such as the phase composition, surface area and bonding interactions between the constituent atoms, for the harsh operating conditions inside the devices. The effort requires good knowledge of the potential effect of changes in these characteristics on the catalytic functionality of the nanoalloys and, hence, on the devices' performance. We present the results from an in operando high-energy X-ray diffraction (HE-XRD) study on the concurrent changes inmore » the structural characteristics and ORR activity of Pd–Cu nanoalloy catalysts as they function at the cathode of a proton exchange membrane fuel cell (PEMFC). We find that the as-prepared Pd–Cu nanoalloys with a chemical composition close to Pd1Cu1 are better ORR catalysts in comparison with Pd1Cu2, i.e. Pd-poor, and Pd3Cu1, i.e. Pd-rich, nanoalloys. Under operating conditions though, the former suffers a big loss in ORR activity appearing as a slow-mode oscillation in the current output of the PEMFC. Losses in ORR activity suffered by the latter also exhibit sudden drops and rises during the PEMFC operation. Through atomic pair distribution function (PDF) analysis of the in operando HE-XRD data, we identify the structural changes of Pd–Cu alloy NPs that are behind the peculiar decay of their ORR activity. The results uncover the instant link between the ever-adapting structural state of ORR nanocatalysts inside an operating PEMFC and the performance of the PEMFC. Besides, our results indicate that, among others, taking control over the intra-particle diffusion of metallic species in nanoalloy catalysts may improve the performance of PEMFCs significantly and, furthermore, in operando HE-XRD can be an effective tool to guide the effort. Finally, we argue that, though showing less optimal ORR activity in the as-prepared state, monophase Pd–Cu alloy catalysts with a composition ranging between Pd1Cu1 and Pd3Cu1 may deliver optimal performance inside operating PEMFCs.« less

Spatially dependent responses of a large-river fish assemblage to bank stabilization and side channels

USGS Publications Warehouse

Reinhold, Ann Marie; Bramblett, Robert G.; Zale, Alexander V.; Poole, Geoffrey C.; Roberts, David W.

2017-01-01

The alteration of rivers by anthropogenic bank stabilization to prevent the erosion of economically valuable lands and structures has become commonplace. However, such alteration has ambiguous consequences for fish assemblages, especially in large rivers. Because most large, temperate rivers have impoundments, it can be difficult to separate the influences of bank stabilization structures from those of main-stem impoundments, especially because both stabilization structures and impoundments can cause side-channel loss. Few large rivers are free flowing and retain extensive side channels, but the Yellowstone River (our study area) is one such river. We hypothesized that in this river (1) bank stabilization has changed fish assemblage structure by altering habitats, (2) side-channel availability has influenced fish assemblage structure by providing habitat heterogeneity, and (3) the influences of bank stabilization and side channels on fish assemblages were spatially scale dependent. We developed a spatially explicit framework to test these hypotheses. Fish assemblage structure varied with the extent of bank stabilization and the availability of side channels; however, not all assemblage subsets were influenced. Nevertheless, bank stabilization and side channels had different and sometimes opposite influences on the fish assemblage. The effects of side channels on fish were more consistent and widespread than those of bank stabilization; the catches of more fishes were positively correlated with side-channel availability than with the extent of bank stabilization. The influences of bank stabilization and side channels on the relative abundances of fish also varied, depending on species and river bend geomorphology. The variation in river morphology probably contributed to the assemblage differences between stabilized and reference river bends; stabilized alluvial pools were deeper than reference alluvial pools, but the depths of stabilized and reference bluff pools did not differ. The strengths of the relationships among fish assemblages, bank stabilization, and side channels were spatially scale dependent; optimum spatial scales ranged from less than 200 m to 3,200 m up- and downstream, suggesting that bank stabilization and side channels influenced fish assemblages across multiple spatial scales.

Apparatus for draining lower drywell pool water into suppresion pool in boiling water reactor

DOEpatents

Gluntz, Douglas M.

1996-01-01

An apparatus which mitigates temperature stratification in the suppression pool water caused by hot water drained into the suppression pool from the lower drywell pool. The outlet of a spillover hole formed in the inner bounding wall of the suppression pool is connected to and in flow communication with one end of piping. The inlet end of the piping is above the water level in the suppression pool. The piping is routed down the vertical downcomer duct and through a hole formed in the thin wall separating the downcomer duct from the suppression pool water. The piping discharge end preferably has an elevation at or near the bottom of the suppression pool and has a location in the horizontal plane which is removed from the point where the piping first emerges on the suppression pool side of the inner bounding wall of the suppression pool. This enables water at the surface of the lower drywell pool to flow into and be discharged at the bottom of the suppression pool.

Best Practices and Testing Protocols for Benchmarking ORR Activities of Fuel Cell Electrocatalysts Using Rotating Disk Electrode

DOE PAGES

Kocha, Shyam S.; Shinozaki, Kazuma; Zack, Jason W.; ...

2017-05-02

Thin-film-rotating disk electrodes (TF-RDEs) are the half-cell electrochemical system of choice for rapid screening of oxygen reduction reaction (ORR) activity of novel Pt supported on carbon black supports (Pt/C) electrocatalysts. It has been shown that the magnitude of the measured ORR activity and reproducibility are highly dependent on the system cleanliness, evaluation protocols, and operating conditions as well as ink formulation, composition, film drying, and the resultant film thickness and uniformity. Accurate benchmarks of baseline Pt/C catalysts evaluated using standardized protocols and best practices are necessary to expedite ultra-low-platinum group metal (PGM) catalyst development that is crucial for the imminentmore » commercialization of fuel cell vehicles. We report results of evaluation in three independent laboratories of Pt/C electrocatalysts provided by commercial fuel cell catalyst manufacturers (Johnson Matthey, Umicore, Tanaka Kikinzoku Kogyo - TKK). The studies were conducted using identical evaluation protocols/ink formulation/film fabrication albeit employing unique electrochemical cell designs specific to each laboratory. Furthermore, the ORR activities reported in this work provide a baseline and criteria for selection and scale-up of novel high activity ORR electrocatalysts for implementation in proton exchange membrane fuel cells (PEMFCs).« less

Theoretical predictions for hexagonal BN based nanomaterials as electrocatalysts for the oxygen reduction reaction.

PubMed

Lyalin, Andrey; Nakayama, Akira; Uosaki, Kohei; Taketsugu, Tetsuya

2013-02-28

The catalytic activity for the oxygen reduction reaction (ORR) of both the pristine and defect-possessing hexagonal boron nitride (h-BN) monolayer and H-terminated nanoribbon have been studied theoretically using density functional theory. It is demonstrated that an inert h-BN monolayer can be functionalized and become catalytically active by nitrogen doping. It is shown that the energetics of adsorption of O(2), O, OH, OOH, and H(2)O on N atom impurities in the h-BN monolayer (N(B)@h-BN) is quite similar to that known for a Pt(111) surface. The specific mechanism of destructive and cooperative adsorption of ORR intermediates on the surface point defects is discussed. It is demonstrated that accounting for entropy and zero-point energy (ZPE) corrections results in destabilization of the ORR intermediates adsorbed on N(B)@h-BN, while solvent effects lead to their stabilization. Therefore, entropy, ZPE and solvent effects partly cancel each other and have to be taken into account simultaneously. Analysis of the free energy changes along the ORR pathway allows us to suggest that a N-doped h-BN monolayer can demonstrate catalytic properties for the ORR under the condition that electron transport to the catalytically active center is provided.

Effects of cobalt precursor on pyrolyzed carbon-supported cobalt-polypyrrole as electrocatalyst toward oxygen reduction reaction

PubMed Central

2013-01-01

A series of non-precious metal electrocatalysts, namely pyrolyzed carbon-supported cobalt-polypyrrole, Co-PPy-TsOH/C, are synthesized with various cobalt precursors, including cobalt acetate, cobalt nitrate, cobalt oxalate, and cobalt chloride. The catalytic performance towards oxygen reduction reaction (ORR) is comparatively investigated with electrochemical techniques of cyclic voltammogram, rotating disk electrode and rotating ring-disk electrode. The results are analyzed and discussed employing physiochemical techniques of X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, elemental analysis, and extended X-ray absorption fine structure. It shows that the cobalt precursor plays an essential role on the synthesis process as well as microstructure and performance of the Co-PPy-TsOH/C catalysts towards ORR. Among the studied Co-PPy-TsOH/C catalysts, that prepared with cobalt acetate exhibits the best ORR performance. The crystallite/particle size of cobalt and its distribution as well as the graphitization degree of carbon in the catalyst greatly affects the catalytic performance of Co-PPy-TsOH/C towards ORR. Metallic cobalt is the main component in the active site in Co-PPy-TsOH/C for catalyzing ORR, but some other elements such as nitrogen are probably involved, too. PMID:24229351

High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction

NASA Astrophysics Data System (ADS)

Pargoletti, E.; Cappelletti, G.; Minguzzi, A.; Rondinini, S.; Leoni, M.; Marelli, M.; Vertova, A.

2016-09-01

Nanostructured MnO2 has unique electrocatalytic properties towards the Oxygen Reduction Reaction (ORR, the main cathodic reaction in metal-air devices), representing an excellent alternative to the expensive platinum. Herein, we report the hydrothermal synthesis of bare and 5% Ti-doped α-MnO2 nanoparticles using two different oxidizing agents, namely ammonium persulfate for MH_N samples and potassium permanganate for MH_K ones. The physico-chemical characterizations show that oxidant cations induce different structural, morphological and surface properties of the final powders. Hence, correlations between the different α-MnO2 characteristics and their electrocatalytic performances towards the ORR are drawn, highlighting the diverse effect even on the kinetic point of view. The ORR activity in alkaline media is examined by means of Staircase - Linear Sweep Voltammetry (S-LSV), using Gas Diffusion Electrode (GDE) as the air-cathode. The presence of these nanoparticles in the GDEs leads to a significant shift of the ORR onset potential (∼100 mV) towards less cathodic values, underlining the electrocatalytic efficiency of all the nanopowders. Furthermore, high exchange current densities (j0) are determined for GDEs with Ti-doped MnO2, comparable to the well-performing Pd45Pt5Sn50, and making it a promising material for the ORR.

Best Practices and Testing Protocols for Benchmarking ORR Activities of Fuel Cell Electrocatalysts Using Rotating Disk Electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocha, Shyam S.; Shinozaki, Kazuma; Zack, Jason W.

Abstract Thin-film-rotating disk electrodes (TF-RDEs) are the half-cell electrochemical system of choice for rapid screening of oxygen reduction reaction (ORR) activity of novel Pt supported on carbon black supports (Pt/C) electrocatalysts. It has been shown that the magnitude of the measured ORR activity and reproducibility are highly dependent on the system cleanliness, evaluation protocols, and operating conditions as well as ink formulation, composition, film drying, and the resultant film thickness and uniformity. Accurate benchmarks of baseline Pt/C catalysts evaluated using standardized protocols and best practices are necessary to expedite ultra-low-platinum group metal (PGM) catalyst development that is crucial for themore » imminent commercialization of fuel cell vehicles. We report results of evaluation in three independent laboratories of Pt/C electrocatalysts provided by commercial fuel cell catalyst manufacturers (Johnson Matthey, Umicore, Tanaka Kikinzoku Kogyo—TKK). The studies were conducted using identical evaluation protocols/ink formulation/film fabrication albeit employing unique electrochemical cell designs specific to each laboratory. The ORR activities reported in this work provide a baseline and criteria for selection and scale-up of novel high activity ORR electrocatalysts for implementation in proton exchange membrane fuel cells (PEMFCs).« less

Best Practices and Testing Protocols for Benchmarking ORR Activities of Fuel Cell Electrocatalysts Using Rotating Disk Electrode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocha, Shyam S.; Shinozaki, Kazuma; Zack, Jason W.

Thin-film-rotating disk electrodes (TF-RDEs) are the half-cell electrochemical system of choice for rapid screening of oxygen reduction reaction (ORR) activity of novel Pt supported on carbon black supports (Pt/C) electrocatalysts. It has been shown that the magnitude of the measured ORR activity and reproducibility are highly dependent on the system cleanliness, evaluation protocols, and operating conditions as well as ink formulation, composition, film drying, and the resultant film thickness and uniformity. Accurate benchmarks of baseline Pt/C catalysts evaluated using standardized protocols and best practices are necessary to expedite ultra-low-platinum group metal (PGM) catalyst development that is crucial for the imminentmore » commercialization of fuel cell vehicles. We report results of evaluation in three independent laboratories of Pt/C electrocatalysts provided by commercial fuel cell catalyst manufacturers (Johnson Matthey, Umicore, Tanaka Kikinzoku Kogyo - TKK). The studies were conducted using identical evaluation protocols/ink formulation/film fabrication albeit employing unique electrochemical cell designs specific to each laboratory. Furthermore, the ORR activities reported in this work provide a baseline and criteria for selection and scale-up of novel high activity ORR electrocatalysts for implementation in proton exchange membrane fuel cells (PEMFCs).« less

Refining cocoon to prepare (N, S, and Fe) ternary-doped porous carbon aerogel as efficient catalyst for the oxygen reduction reaction in alkaline medium

NASA Astrophysics Data System (ADS)

Li, Changqing; Sun, Fengzhan; Lin, Yuqing

2018-04-01

Various advanced sulfur doped Fe-N-C non-noble metal catalysts of oxygen reduction reaction (ORR) have been recently designed and reported with excellent catalytic activity. Herein, we refined cocoon with several steps to form silk fibroin solution, treated with iron salt to prepare an easy available, heteroatom (N, S, and Fe) ternary-doped, porous carbon aerogel (HDCA). Heteroatom existed in organic compounds in silk fibroin endow active site for ORR of the resultant carbon frameworks. Moreover, the amino acids presented in silk fibroin acted as ligands, functioning with Fe ions to form FeNx coordination compounds, which also served as active sites towards ORR. The synthesized HDCA electrocatalysts, especially HDCA-800 (obtained at 800 °C) displayed excellent catalytic activity with onsets, half-wave potential of 0.94 V, 0.79 V and higher limited current density of 3.80 mA cm-2 through a near four-electron reduction pathway with an average electron transferred number of 3.86, making them promising alternatives for state-of-the-art ORR electrocatalysts in fuel cell field. The porous structure with synergistic effect of N and S heteroatom doping has been proposed to play a key role in facilitating the desired ORR reaction.

VIEW OF EAST SIDE OF FILTER ROOM/BATHHOUSE BUILDING S196, FACING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF EAST SIDE OF FILTER ROOM/BATHHOUSE BUILDING S-196, FACING SOUTHWEST. - U.S. Naval Base, Pearl Harbor, Outdoor Swimming Pool, Corner of Liscome Bay Street & St. Lo Avenue, Pearl City, Honolulu County, HI

Boosting ORR Catalytic Activity by Integrating Pyridine-N Dopants, a High Degree of Graphitization, and Hierarchical Pores into a MOF-Derived N-Doped Carbon in a Tandem Synthesis.

PubMed

Liu, Dandan; Li, Liangjun; Xu, Huanfei; Dai, Pengcheng; Wang, Ying; Gu, Xin; Yan, Liting; Zhao, Guoming; Zhao, Xuebo

2018-05-18

N-doped carbon materials represent promising metal-free electrocatalysts for the oxygen reduction reaction (ORR), the cathode reaction in fuel cells, metal-air batteries, and so on. A challenge for optimizing the ORR catalytic activities of these electrocatalysts is to tune their local structures and chemical compositions in a rational and controlled way that can achieve the synergistic function of each factor. Herein, we report a tandem synthetic strategy that integrates multiple contributing factors into an N-doped carbon. With an N-containing MOF (ZIF-8) as the precursor, carbonization at higher temperatures leads to a higher degree of graphitization. Subsequent NH 3 etching of this highly graphitic carbon enabled the introduction of a higher content of pyridine-N sites and higher porosity. By optimizing these three factors, the resultant carbon materials displayed ORR activity that was far superior to that of carbon derived from a one-step pyrolysis. The onset potential of 0.955 V versus a reversible hydrogen electrode (RHE) and the half-wave potential of 0.835 V versus RHE are among the top ranks of metal-free ORR catalysts and are comparable to commercial Pt/C (20 wt %) catalysts. Kinetic studies revealed lower H 2 O 2 yields, higher electron-transfer numbers, and lower Tafel slopes for these carbon materials compared with that derived from a one-step carbonization. These findings verify the effectiveness of this tandem synthetic strategy to enhance the ORR activity of N-doped carbon materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of clinical outcome after first-line platinum-based chemotherapy in different types of KRAS mutated advanced non-small-cell lung cancer.

PubMed

Mellema, Wouter W; Masen-Poos, Lucie; Smit, Egbert F; Hendriks, Lizza E L; Aerts, Joachim G; Termeer, Arien; Goosens, Martijn J; Smit, Hans J M; van den Heuvel, Michel M; van der Wekken, Anthonie J; Herder, Gerarda J M; Krouwels, Frans H; Stigt, Jos A; van den Borne, Ben E E M; Haitjema, Tjeerd J; Staal-Van den Brekel, Agnes J; van Heemst, Robbert C; Pouw, Ellen; Dingemans, Anne-Marie C

2015-11-01

As suggested by in-vitro data, we hypothesize that subtypes of KRAS mutated non-small cell lung cancer (NSCLC) respond differently to chemotherapy regimens. Patients with advanced NSCLC and known KRAS mutation, treated with first-line platinum-based chemotherapy, were retrieved from hospital databases. to investigate overall response rate (ORR), progression free survival (PFS) and overall survival (OS) between different types of platinum-based chemotherapy per type of KRAS mutation. 464 patients from 17 hospitals, treated between 2000 and 2013, were included. The majority of patients had stage IV disease (93%), had a history of smoking (98%) and known with an adenocarcinoma (91%). Most common types of KRAS mutation were G12C (46%), G12V (20%) and G12D (10%). Platinum was combined with pemetrexed (n=334), taxanes (n=68) or gemcitabine (n=62). Patients treated with taxanes had a significant improved ORR (50%) compared to pemetrexed (21%) or gemcitabine (25%; p<0.01). Patients treated with bevacizumab in addition to taxanes (n=38) had the highest ORR (62%). The PFS was significantly improved in patients treated with taxanes compared to pemetrexed (HR=0.72, p=0.02), but not OS (HR=0.87, p=0.41). In patients with G12V, significantly improved ORR (p<0.01) was observed for taxanes, but not PFS or OS. Patients with G12C or G12D mutation had comparable ORR, PFS and OS in all treatment groups. KRAS mutated NSCLC patients treated with taxane-based chemotherapy had best ORR. Response to chemotherapy regimens was different in types of KRAS mutation. Especially patients with G12V had better response to taxane treatment. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Survey of protected terrestrial vertebrates on the Oak Ridge Reservation. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, J.M.; Vail, E.R.; Webb, J.W.

1996-07-01

This document is the final report on surveys of protected terrestrial vertebrates on the Oak Ridge Reservation (ORR) conducted from October 1994 through May 1996. The surveys were undertaken to gain information that could help prevent or minimize the potential impacts of projects on the ORR to species listed by the state or federal government as endangered, threatened, or in need of management; federal species of concern were also included. The results of the survey will assist in the effective management of the natural resources of the ORR. Currently, there are 69 species of federal or state listed terrestrial vertebratesmore » (20 reptiles and amphibians, 20 mammals, and 29 birds) that may occur in Tennessee. Listed animal species that might be present on the ORR were targeted for survey using a prioritization system based on historical and recent sightings, known species distributions, presence of suitable habitat, literature reviews, and personal communications. Survey methods included trapping, seining, monitoring of artificial covers, active searching, and avian surveys. Surveys were conducted during the time of year when each targeted species was most likely to be encountered. The surveys confirmed the presence of 20 threatened and endangered species on the ORR. This report also includes some ancillary information. Records are provided for nonlisted species (44 species of reptiles and amphibians, 155 species of birds, and 28 species of mammals). Categorization of survey sites into 1 or more of 19 habitat types, which are briefly described, is presented. Notes are summarized on the occurrence of threatened and endangered species on the ORR. Finally, this report also lists threatened and endangered species not found that might be located by additional surveys, recommends three survey areas for natural-area status due to wildlife value, and suggests several avenues for future work.« less

Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum Nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matanovic, Ivana; Kent, Paul; Garzon, Fernando

2012-07-13

The structure, stability, and catalytic activity of a number of single- and double-wall platinum (n,m) nanotubes ranging in diameter from 0.3 to 2.0 nm were studied using plane-wave based density functional theory in the gas phase and water environment. The change in the catalytic activity toward the oxygen reduction reaction (ORR) with the size and chirality of the nanotube was studied by calculating equilibrium adsorption potentials for ORR intermediates and by constructing free energy diagrams in the ORR dissociative mechanism network. In addition, the stability of the platinum nanotubes is investigated in terms of electrochemical dissolution potentials and by determiningmore » the most stable state of the material as a function of pH and potential, as represented in Pourbaix diagrams. Our results show that the catalytic activity and the stability toward electrochemical dissolution depend greatly on the diameter and chirality of the nanotube. On the basis of the estimated overpotentials for ORR, we conclude that smaller, approximately 0.5 nm in diameter single-wall platinum nanotubes consistently show a huge, up to 400 mV larger overpotential than platinum, indicating very poor catalytic activity toward ORR. This is the result of substantial structural changes induced by the adsorption of any chemical species on these tubes. Single-wall n = m platinum nanotubes with a diameter larger than 1 nm have smaller ORR overpotentials than bulk platinum for up to 180 mV and thus show improved catalytic activity relative to bulk. We also predict that these nanotubes can endure the highest cell potentials but dissolution potentials are still for 110 mV lower than for the bulk, indicating a possible corrosion problem.« less

2. Light tower and keeper's house, view southwest, north northeast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Light tower and keeper's house, view southwest, north northeast side of tower, northeast and northwest sides of keeper's house - Wood Island Light Station, East end of Wood Island, at mouth of Soo River, Biddeford Pool, York County, ME

VIEW OF SOUTH AND EAST SIDES OF FILTER ROOM/BATHHOUSE BUILDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF SOUTH AND EAST SIDES OF FILTER ROOM/BATHHOUSE BUILDING S-196, FACING NORTHWEST. - U.S. Naval Base, Pearl Harbor, Outdoor Swimming Pool, Corner of Liscome Bay Street & St. Lo Avenue, Pearl City, Honolulu County, HI

VIEW OF NORTH AND WEST SIDES OF FILTER ROOM/BATHHOUSE BUILDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF NORTH AND WEST SIDES OF FILTER ROOM/BATHHOUSE BUILDING S-196, FACING SOUTHEAST. - U.S. Naval Base, Pearl Harbor, Outdoor Swimming Pool, Corner of Liscome Bay Street & St. Lo Avenue, Pearl City, Honolulu County, HI

75 FR 152 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-04

... OMB Review; Comment Request Title: Refugee Unaccompanied Minor Placement Report & Minor Progress... to administer the Unaccompanied Refugee Minor (URM) program. The ORR-3 (Placement Report) is submitted to the Office of Refugee Resettlement (ORR) by the State agency at initial placement within 30...

Graphene-cobaltite-Pd hybrid materials for use as efficient bifunctional electrocatalysts in alkaline direct methanol fuel cells.

PubMed

Sharma, Chandra Shekhar; Awasthi, Rahul; Singh, Ravindra Nath; Sinha, Akhoury Sudhir Kumar

2013-12-14

Hybrid materials comprising of Pd, MCo2O4 (where M = Mn, Co or Ni) and graphene have been prepared for use as efficient bifunctional electrocatalysts in alkaline direct methanol fuel cells. Structural and electrochemical characterizations were carried out using X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, chronoamperometry and cyclic, CO stripping, and linear sweep voltammetries. The study revealed that all the three hybrid materials are active for both methanol oxidation (MOR) and oxygen reduction (ORR) reactions in 1 M KOH. However, the Pd-MnCo2O4/GNS hybrid electrode exhibited the greatest MOR and ORR activities. This active hybrid electrode has also outstanding stability under both MOR and ORR conditions, while Pt- and other Pd-based catalysts undergo degradation under similar experimental conditions. The Pd-MnCo2O4/GNS hybrid catalyst exhibited superior ORR activity and stability compared to even Pt in alkaline solutions.

Surface Structure Dependent Electrocatalytic Activity of Co3O4 Anchored on Graphene Sheets toward Oxygen Reduction Reaction

PubMed Central

Xiao, Junwu; Kuang, Qin; Yang, Shihe; Xiao, Fei; Wang, Shuai; Guo, Lin

2013-01-01

Catalytic activity is primarily a surface phenomenon, however, little is known about Co3O4 nanocrystals in terms of the relationship between the oxygen reduction reaction (ORR) catalytic activity and surface structure, especially when dispersed on a highly conducting support to improve the electrical conductivity and so to enhance the catalytic activity. Herein, we report a controllable synthesis of Co3O4 nanorods (NR), nanocubes (NC) and nano-octahedrons (OC) with the different exposed nanocrystalline surfaces ({110}, {100}, and {111}), uniformly anchored on graphene sheets, which has allowed us to investigate the effects of the surface structure on the ORR activity. Results show that the catalytically active sites for ORR should be the surface Co2+ ions, whereas the surface Co3+ ions catalyze CO oxidation, and the catalytic ability is closely related to the density of the catalytically active sites. These results underscore the importance of morphological control in the design of highly efficient ORR catalysts. PMID:23892418

Oxygen Reduction Reaction on Ag(111) in Alkaline Solution: A Combined Density Functional Theory and Kinetic Monte Carlo Study

DOE PAGES

Liu, Shizhong; White, Michael G.; Liu, Ping

2018-01-25

We reported a detailed mechanistic study of the oxygen reduction reaction (ORR) on the model Ag(111) surface in alkaline solution by using density functional theory (DFT) and Kinetic Monte Carlo (KMC) simulations, in which multiple pathways involving either 2 e - or 4 e - mechanisms were included. The theoretical modelling presented here is able to reproduce the experimentally measured polarization curves in both low and high potential regions. An electrochemical 4 e - network including both a chemisorbed water (*H 2O)-mediated 4 e - associative pathway and the conventional associative pathway was identified to dominate the ORR mechanism. Onmore » the basis of the mechanistic understanding derived from these calculations, the ways to promote the ORR on Ag(111) were provided, including facilitating *OH removal, **O 2 reduction by *H 2O, and suppressing **O 2 desorption. Finally, the origin of the different ORR behaviors of Ag(111) and Pt(111) was also discussed in detail.« less

Oxygen Reduction Reaction on Ag(111) in Alkaline Solution: A Combined Density Functional Theory and Kinetic Monte Carlo Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Shizhong; White, Michael G.; Liu, Ping

We reported a detailed mechanistic study of the oxygen reduction reaction (ORR) on the model Ag(111) surface in alkaline solution by using density functional theory (DFT) and Kinetic Monte Carlo (KMC) simulations, in which multiple pathways involving either 2 e - or 4 e - mechanisms were included. The theoretical modelling presented here is able to reproduce the experimentally measured polarization curves in both low and high potential regions. An electrochemical 4 e - network including both a chemisorbed water (*H 2O)-mediated 4 e - associative pathway and the conventional associative pathway was identified to dominate the ORR mechanism. Onmore » the basis of the mechanistic understanding derived from these calculations, the ways to promote the ORR on Ag(111) were provided, including facilitating *OH removal, **O 2 reduction by *H 2O, and suppressing **O 2 desorption. Finally, the origin of the different ORR behaviors of Ag(111) and Pt(111) was also discussed in detail.« less

[Systematic review and Meta-analysis of Shenqi Fuzheng injection combined with first-line chemotherapy for non-small cell lung cancer].

PubMed

Hao, Teng-teng; Xie, Yan-ming; Liao, Xing; Wang, Jing

2015-10-01

The paper is to systematically evaluate the effect and safety of Shenqi Fuzheng injection (SFI) combined with first-line chemotherapy for non-small cell lung cancer (NSCLC). Randomized controlled trials (RCTs) on Shenqi Fuzheng injection (SFI) combined with first-line chemotherapy (experiment group) and chemotherapy alone group ( control group) were electronically retrieved from Medline, EMbase, Clinical Trials, Cochrane Library, CBM, CNKI, VIP, and Wanfang Data base. All trials were assessed for quality according to the Cochrane Reviewer's Handbook for Systematic Reviews of Intervention and then Meta-analysis was performed withRevMan5. 2 Software. A total of 43 RCTs (3433 patients) were included after screening and selecting. Results of Meta-analysis showed that: Objective remission rate (ORR): ORR of experimental group was about 20% higher than that of control group [RR = 1.23, 95% CI (1.11,1.35), P < 0.0001]. Disease control rate (DCR):DCR of SFI combined with first-line chemotherapy was 11% higher than that of first-line chemotherapy alone [RR = 1.11, 95% CI (1.07, 1.16), P < 0.000 01]. Life quality evaluated by Kosovan performance status (KPS) showed that: life quality improvement rate of experimental group was about twice of that in control group [RR = 2.02, 95% CI (1.81, 2.26), P < 0.000 01]. Toxic and side reaction analysis showed that: the incidence of side reactions in experimental group was about 50% lower than that in control group [RR = 0.59, 95% CI (0.53, 0.66), P < 0.000 01]. Immune function test showed that: the function of experimental group was 3.2 (standard deviations) times greater than that of control group [MD = 3.23, 95% CI (2.86, 3.60), P < 0.000 01]. We can see that SFI combined with first-line chemotherapy for NSCLC can increase objective efficacy, improve life quality, decrease toxic and side reactionsinduced by chemotherapy, and improve the immune functions. As most of the included studies in this systematic evaluation had poor quality, the evidence to support conclusion was weak, so it was necessary to conduct more multi-center clinical trials with high quality methods and rigorous design.

Association Between Plasma Genotyping and Outcomes of Treatment With Osimertinib (AZD9291) in Advanced Non–Small-Cell Lung Cancer

PubMed Central

Thress, Kenneth S.; Alden, Ryan S.; Lawrance, Rachael; Paweletz, Cloud P.; Cantarini, Mireille; Yang, James Chih-Hsin; Barrett, J. Carl; Jänne, Pasi A.

2016-01-01

Purpose Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have demonstrated potent activity against TKI resistance mediated by EGFR T790M. We studied whether noninvasive genotyping of cell-free plasma DNA (cfDNA) is a useful biomarker for prediction of outcome from a third-generation EGFR-TKI, osimertinib. Methods Plasma was collected from all patients in the first-in-man study of osimertinib. Patients who were included had acquired EGFR-TKI resistance and evidence of a common EGFR-sensitizing mutation. Genotyping of cell-free plasma DNA was performed by using BEAMing. Plasma genotyping accuracy was assessed by using tumor genotyping from a central laboratory as reference. Objective response rate (ORR) and progression-free survival (PFS) were analyzed in all T790M-positive or T790M-negative patients. Results Sensitivity of plasma genotyping for detection of T790M was 70%. Of 58 patients with T790M-negative tumors, T790M was detected in plasma of 18 (31%). ORR and median PFS were similar in patients with T790M-positive plasma (ORR, 63%; PFS, 9.7 months) or T790M-positive tumor (ORR, 62%; PFS, 9.7 months) results. Although patients with T790M-negative plasma had overall favorable outcomes (ORR, 46%; median PFS, 8.2 months), tumor genotyping distinguished a subset of patients positive for T790M who had better outcomes (ORR, 69%; PFS, 16.5 months) as well as a subset of patients negative for T790M with poor outcomes (ORR, 25%; PFS, 2.8 months). Conclusion In this retrospective analysis, patients positive for T790M in plasma have outcomes with osimertinib that are equivalent to patients positive by a tissue-based assay. This study suggests that, upon availability of validated plasma T790M assays, some patients could avoid a tumor biopsy for T790M genotyping. As a result of the 30% false-negative rate of plasma genotyping, those with T790M-negative plasma results still need a tumor biopsy to determine presence or absence of T790M. PMID:27354477

Association Between Plasma Genotyping and Outcomes of Treatment With Osimertinib (AZD9291) in Advanced Non-Small-Cell Lung Cancer.

PubMed

Oxnard, Geoffrey R; Thress, Kenneth S; Alden, Ryan S; Lawrance, Rachael; Paweletz, Cloud P; Cantarini, Mireille; Yang, James Chih-Hsin; Barrett, J Carl; Jänne, Pasi A

2016-10-01

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have demonstrated potent activity against TKI resistance mediated by EGFR T790M. We studied whether noninvasive genotyping of cell-free plasma DNA (cfDNA) is a useful biomarker for prediction of outcome from a third-generation EGFR-TKI, osimertinib. Plasma was collected from all patients in the first-in-man study of osimertinib. Patients who were included had acquired EGFR-TKI resistance and evidence of a common EGFR-sensitizing mutation. Genotyping of cell-free plasma DNA was performed by using BEAMing. Plasma genotyping accuracy was assessed by using tumor genotyping from a central laboratory as reference. Objective response rate (ORR) and progression-free survival (PFS) were analyzed in all T790M-positive or T790M-negative patients. Sensitivity of plasma genotyping for detection of T790M was 70%. Of 58 patients with T790M-negative tumors, T790M was detected in plasma of 18 (31%). ORR and median PFS were similar in patients with T790M-positive plasma (ORR, 63%; PFS, 9.7 months) or T790M-positive tumor (ORR, 62%; PFS, 9.7 months) results. Although patients with T790M-negative plasma had overall favorable outcomes (ORR, 46%; median PFS, 8.2 months), tumor genotyping distinguished a subset of patients positive for T790M who had better outcomes (ORR, 69%; PFS, 16.5 months) as well as a subset of patients negative for T790M with poor outcomes (ORR, 25%; PFS, 2.8 months). In this retrospective analysis, patients positive for T790M in plasma have outcomes with osimertinib that are equivalent to patients positive by a tissue-based assay. This study suggests that, upon availability of validated plasma T790M assays, some patients could avoid a tumor biopsy for T790M genotyping. As a result of the 30% false-negative rate of plasma genotyping, those with T790M-negative plasma results still need a tumor biopsy to determine presence or absence of T790M. © 2016 by American Society of Clinical Oncology.

Randomized Phase II Study of Azacitidine Alone or in Combination With Lenalidomide or With Vorinostat in Higher-Risk Myelodysplastic Syndromes and Chronic Myelomonocytic Leukemia: North American Intergroup Study SWOG S1117.

PubMed

Sekeres, Mikkael A; Othus, Megan; List, Alan F; Odenike, Olatoyosi; Stone, Richard M; Gore, Steven D; Litzow, Mark R; Buckstein, Rena; Fang, Min; Roulston, Diane; Bloomfield, Clara D; Moseley, Anna; Nazha, Aziz; Zhang, Yanming; Velasco, Mario R; Gaur, Rakesh; Atallah, Ehab; Attar, Eyal C; Cook, Elina K; Cull, Alyssa H; Rauh, Michael J; Appelbaum, Frederick R; Erba, Harry P

2017-08-20

Purpose Azacitidine is standard, first-line therapy in higher-risk myelodysplastic syndromes (MDS). Whether azacitidine-based combinations with lenalidomide or vorinostat produce superior overall response rates (ORRs) to azacitidine is not known. Patients and Methods North American Intergroup Study S1117 is a phase II/III trial that randomly assigned patients with higher-risk MDS and chronic myelomonocytic leukemia (CMML) 1:1:1 to azacitidine (75 mg/m 2 /day on days 1 to 7 of a 28-day cycle); azacitidine plus lenalidomide (10 mg/day on days 1 to 21); or azacitidine plus vorinostat (300 mg twice daily on days 3 to 9). The primary phase II end point was improved ORR. Results Of 277 patients from 90 centers, 92 received azacitidine, 93 received azacitidine plus lenalidomide, and 92 received azacitidine plus vorinostat. Median age was 70 years (range, 28 to 93 years), 85 patients (31%) were female, and 53 patients (19%) had CMML. Serious adverse events were similar across arms, although combination-arm patients were more likely to undergo nonprotocol-defined dose modifications ( P < .001).With a median follow-up of 23 months (range, 1 to 43 months), the ORR was 38% for patients receiving azacitidine, 49% for azacitidine plus lenalidomide ( P = .14 v azacitidine), and 27% for azacitidine plus vorinostat ( P = .16 v azacitidine). For patients with CMML, ORR was higher for azacitidine plus lenalidomide versus azacitidine (68% v 28%, P = .02) but similar for all arms across cytogenetic subgroups, as was remission duration and overall survival. ORR was higher with mutations in DNMT3A and lower for SRSF2, whereas ORR duration improved with fewer mutations. Lenalidomide dose reduction was associated with worse overall survival (hazard ratio, 1.30; P = .05). Conclusion Patients with higher-risk MDS treated with azacitidine-based combinations had similar ORR to azacitidine monotherapy, although patients with CMML benefitted from azacitidine plus lenalidomide. The efficacy of combination regimens may have been affected by dose modifications.

A photonic chip based frequency discriminator for a high performance microwave photonic link.

PubMed

Marpaung, David; Roeloffzen, Chris; Leinse, Arne; Hoekman, Marcel

2010-12-20

We report a high performance phase modulation direct detection microwave photonic link employing a photonic chip as a frequency discriminator. The photonic chip consists of five optical ring resonators (ORRs) which are fully programmable using thermo-optical tuning. In this discriminator a drop-port response of an ORR is cascaded with a through response of another ORR to yield a linear phase modulation (PM) to intensity modulation (IM) conversion. The balanced photonic link employing the PM to IM conversion exhibits high second-order and third-order input intercept points of + 46 dBm and + 36 dBm, respectively, which are simultaneously achieved at one bias point.

Develop high activity, low cost non-PGM fuel cell electrocatalyst and stable supports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colon-Mercado, H. R.; Elvington, M. C.; Garcia-Diaz, B. L.

2016-09-28

A unique approach has been developed to probe the non-PGM catalyst active site for the Oxygen Reduction Reaction (ORR) for PEMFC. Iron based functionalities have been engineered into Metallic Organic Framework (MOF) catalysts to evaluate their impact on activity for the ORR. A series of FePhen@MOF catalysts have been synthesized with varying [Fe] to investigate the effect on electrochemical and electrocatalytic properties. The magnitude of the Fe II/III redox couple and the electrochemical surface area are analyzed to determine if there is a correlation between [Fe] and the ORR onset potential and/or the relative number of active sites.

Impact of Venetoclax Exposure on Clinical Efficacy and Safety in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia.

PubMed

Freise, Kevin J; Jones, Aksana K; Eckert, Doerthe; Mensing, Sven; Wong, Shekman L; Humerickhouse, Rod A; Awni, Walid M; Salem, Ahmed Hamed

2017-05-01

Venetoclax is a selective, potent, first-in-class B-cell lymphoma-2 inhibitor that restores apoptosis in cancer cells and has demonstrated efficacy in a variety of hematological malignancies. The objective of this research was to characterize the relationship between venetoclax exposures and efficacy and safety in patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). A total of 272 and 338 patients from four clinical studies were pooled for the exposure-efficacy and exposure-safety analyses, respectively. Demographics, baseline disease characteristics, and select co-medications were evaluated for their impact on efficacy (lymphocytes, tumor size, objective response [OR]) and safety (neutropenia and infection). Higher venetoclax concentrations led to a more rapid decrease in lymphocyte counts and tumor size, which translated into patients more rapidly achieving OR. The 17p deletion somatic mutation was not identified, in any of the analyses, to affect the responsiveness of patients to venetoclax. Model-based simulations of lymphocyte counts and tumor size estimated an OR rate (ORR) of 84.8 % (95 % confidence interval 81.5-88.0 %) at a venetoclax dosage of 400 mg daily, with minimal increase in ORR at higher doses. The safety analyses of the adverse events (grade 3 or higher) of neutropenia and infection indicated that higher average venetoclax concentrations were not associated with an increase in adverse events. The exposure-response analyses indicated that a venetoclax dosage regimen of 400 mg daily results in a high (>80 %) probability of achieving OR in R/R CLL/SLL patients, with minimal probability of increasing neutropenia or infection with higher exposures.

Looking for the best immune-checkpoint inhibitor in pre-treated NSCLC patients: An indirect comparison between nivolumab, pembrolizumab and atezolizumab.

PubMed

Passiglia, Francesco; Galvano, Antonio; Rizzo, Sergio; Incorvaia, Lorena; Listì, Angela; Bazan, Viviana; Russo, Antonio

2018-03-15

Immune-checkpoint inhibitors represent the new standard of care in patients with advanced NSCLC who progressed after first-line treatment. This work aim to assess any difference in both efficacy and safety profiles among Nivolumab, Pembrolizumab and Atezolizumab in pre-treated NSCLC patients. Randomized clinical trials comparing immune-checkpoint inhibitor versus docetaxel in pre-treated patients with advanced NSCLC were included and direct comparison meta-analysis of selected trials have been performed. Subsequently the summary estimates of Nivolumab, Pembrolizumab and Atezolizumab emerging from the direct meta-analysis were selected to provide the pooled estimates of hazard ratio (HR) and relative risk (RR) for the indirect comparisons among these agents. A total of 5 studies met the selection criteria and were included in the meta-analysis. Indirect comparisons for efficacy outcomes showed the RR for ORR nivolumab versus atezolizumab 1.66 (95% CI 1.07-2.58), pembrolizumab versus atezolizumab 1.94 (95% CI 1.30-2.90). No significant differences in both PFS and OS have been observed. Indirect comparisons for safety showed the RR for G3-5 AEs nivolumab versus pembrolizumab 0.41 (95% CI 0.29-0.60), nivolumab versus atezolizumab 0.50 (95% CI 0.35-0.72). No significant differences in both pneumonitis and discontinuation rate have been observed. The results of this work revealed that nivolumab and pembrolizumab are associated with a significant increase of ORR as compared to atezolizumab and nivolumab is associated with a significant lower incidence of G3-5 AEs as compared to the other drugs. These evidences could support the oncologists to select the best drug for each patient. © 2017 UICC.

Solution of the Orr-Sommerfeld equation for the Blausius boundary-layer documentation of program ORRBL and a test case

NASA Technical Reports Server (NTRS)

Biringen, S.; Danabasoglu, G.

1988-01-01

A Chebyshev matrix collocation method is outlined for the solution of the Orr-Sommerfeld equation for the Blausius boundary layer. User information is provided for FORTRAN program ORRBL which solves the equation by the QR method.

1. Keeper's house and light tower, view north northeast, southwest ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Keeper's house and light tower, view north northeast, southwest and southeast sides of house, northwest and southwest sides of tower - Wood Island Light Station, East end of Wood Island, at mouth of Soo River, Biddeford Pool, York County, ME

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Shizhong; White, Michael G.; Liu, Ping

Here, we report a detailed mechanistic study of the oxygen reduction reaction (ORR) on Pt(111) in alkaline solution, combining density functional theory and kinetic Monte Carlo simulations. A complex reaction network including four possible pathways via either 2e – or 4e – transfer is established and is able to reproduce the experimental measured polarization curve at both low- and high-potential regions. Our results show that it is essential to account for solvation by water and the dynamic coverage of *OH to describe the reaction kinetics well. In addition, a chemisorbed water (*H 2O)-mediated mechanism including 4e – transfers is identified,more » where the reduction steps via *H 2O on the surface are potential-independent and only the final removal of *OH from the surface in the form of OH –(aq) contributes to the current. For the ORR in alkaline solutions, such a mechanism is more competitive than the associative and dissociative mechanisms typically used to describe the ORR in acid solution. Finally, *OH and **O 2 intermediates are found to be critically important for tuning the ORR activity of Pt in alkaline solution. To enhance the activity, the binding of Pt should be tuned in such a way that *OH binding is weak enough to release more surface sites under working conditions, while **O 2 binding is strong enough to enable the ORR via the 4e – transfer mechanism.« less

40 CFR 81.306 - Colorado.

Code of Federal Regulations, 2010 CFR

2010-07-01

... boundary, then: east along the County line to Elbert Road; south on Elbert Road to Judge Orr Road; east on Judge Orr Road to Ellicott Highway; south on Ellicott Highway to Squirrel Creek Road; west on Squirrel Creek Road to Williams Creek; south along Williams Creek to the confluence of Williams and Fountain...

Oak Ridge Reservation. Physical Characteristics and National Resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parr, Patricia Dreyer; Joan, F. Hughes

The topology, geology, hydrology, vegetation, and wildlife of the Oak Ridge Reservation (ORR) provide a complex and intricate array of resources that directly impact land stewardship and use decisions. The purpose of this document is to consolidate general information regarding the natural resources and physical characteristics of the ORR.

43 CFR 418.1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Land and Reservoir Co., 503 F. Supp. 877 (D. Nev. 1980)) and the Orr Ditch decree (United States v. Orr Water Ditch Co., Equity No. A-3 (D. Nev.)) District means the Truckee-Carson Irrigation District or any other approved Newlands Project operator. Eligible land means Project land which at the time of delivery...

43 CFR 418.1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Land and Reservoir Co., 503 F. Supp. 877 (D. Nev. 1980)) and the Orr Ditch decree (United States v. Orr Water Ditch Co., Equity No. A-3 (D. Nev.)) District means the Truckee-Carson Irrigation District or any other approved Newlands Project operator. Eligible land means Project land which at the time of delivery...

Operando Raman Micro Spectroscopy of Polymer Electrolyte Fuel Cells

DTIC Science & Technology

2016-01-16

understanding of the processes such as oxygen reduc- tion reaction (ORR), carbon corrosion, and catalysis process of ORR in PEMFCs catalyzed by Pt or...Journal of Membrane Science, 392, 88 (2012). 46. F. Jaouen, F. Charreteur, and J. P. Dodelet, “Fe-based catalysts for oxygen reduction in PEMFCs

Human-Computer System Development Methodology for the Dialogue Management System.

DTIC Science & Technology

1982-05-01

methodologies [HOSIJ78] are given below: I. The Michael Jackson Methodology [JACKM75] 2. The Warnier-Orr Methodolgy [HOSIJ78] 3. SADT (Structured...All the mentioned methodologies use top-down development strategy. The first two methodologies above ( Michael Jackson and Warnier-Orr) use data as the

Credit PSR. View looking north northeast (12°) across surface remains ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit PSR. View looking north northeast (12°) across surface remains of North Base swimming pool. The southeast edge of the pool appearing in the foreground may seem to be a sidewalk to the casual observer; the wavy inside edge of this walk matches the pool side visible in historic construction photos (See HAER photo CA-170-Q-2). The telephone pole in the midground of the view is inside the pool proper. Building 4312 (Liquid Oxygen Repair Facility) appears in left background, Building 4456 (Fire House No. 4) in middle background, and Building 4444 (Communications Building) in right background - Edwards Air Force Base, North Base, Swimming Pool, Second Street, Boron, Kern County, CA

2D molybdenum disulphide (2D-MoS2) modified electrodes explored towards the oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Rowley-Neale, Samuel J.; Fearn, Jamie M.; Brownson, Dale A. C.; Smith, Graham C.; Ji, Xiaobo; Banks, Craig E.

2016-08-01

Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm-2 modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm-2 modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr04073j

Etude de l'electrocatalyse de la reduction de l'oxygene sur des alliages de palladium cuivre

NASA Astrophysics Data System (ADS)

Fouda-Onana, Frederic

This thesis is on the development of the ORR on Pd-Cu alloys in acid medium. Density Functional Theory (DFT) was used to determine the intrinsic properties of the alloys. The alloys were fabricated by RF sputtering on glassy carbon support and chemical salt reduction on carbon support. They characterised by electrochemical methods and correlations were made between the intrinsic properties and the experimental electrochemical parameters. These correlations were used to explain the electrocatalytic performance of the ORR on these aklooys and to determine the mechanism of this reaction on these electrocatalysts. Accordingly the following aspects were studied in details. In the first step, ab initio investigations of the effect of the intermediate adsorption on the variation of the reversible potential of the ORR on Pt(100) was shown. Density Functional Theory (DFT) was used to determine the energies and the geometry parameters of the intermediates which can be adsorbed on Pt(100) during the oxygen reduction reaction (ORR) and their effect on the . The Comparison of these energies and parameters using the Bridge or the Griffiths sites adsorption mechanism suggests that the two paths are feasible. In both mechanisms, the total adsorption energies of the intermediates species continuously decrease. Moreover, according to the geometry analysis, the O-O bond distance in H2O2 is higher in both (Bridge and Griffiths) processes compared to the gas phase. Such a result suggests a dissociative H2O2 adsorption whatever the type of the involved mechanism involved. In the second step, the Oxygen reduction reaction (ORR) on palladium-copper alloys was studied through two approaches. The first one is based on the correlations between the surface chemical composition and the kinetics parameters of the ORR. The second approach is focused on the correlations between the adsorption energies of O2 and OH of Pd-Cu(111) surfaces and the electronic properties of the alloys. The adsorbtion energy calculations are based on on ab initio calculation using the program VASP (Vienna ab initio program) in a MeDeA environnement (software purchased from Materials Design, Inc. The studies of the oxygen reduction reaction were performed in an acidic media on Palladium-Copper alloys as catalyst. The variation of the intrinsic metal surface properties (lattice parameter, binding energy, work function (Wf), d-band filling and d-band center epsilond) and O2 and OH adsorption energies of on (111) Pd-Cu surface alloys were determined using ab initio program. Calculations of these parameters were based on plane waves approach on slab system with density functional theory (DFT) using the Vienna ab initio simulation program (VASP). It was shown that insertion of Cu atoms in Pd lattice affects geometric and electronic properties of Pd. These changes influence significantly O2 and OH adsorption. In the third step, the oxygen reduction reaction (ORR) on Pd-Cu catalyst has been studied in acidic media. The palladium alloys were prepared by RF magnetron using a palladium and a copper wafer as targets on the glassy carbon substrate. The dual sputtering we used allowed the deposition of about 1micrometer thin film of Pd-Cu on glassy carbon (GC). The ORR kinetics was studied on these catalysts in 0,1M HClO4. Cyclic voltammetry (CV) was used to determine the electrochemical active surface area (Sa). An increase in Sa with the Cu content in the alloy was observed for the alloys containing more than 50% in Cu. The Pd-Cu alloys containing more than 50% in Cu exhibits a constant value of 23 cm2 for Sa. It was further shown that the ORR on the Pd-Cu alloys proceeds through the 4 electrons transfer mechanism and a Tafel slope of 60 mV/dec. The Pd 50Cu50 exhibits the highest activity for this reaction. The enhancement of the electro catalytic activity is attributed to an optimal d band property that makes easier the OOH dissociative adsorption which is considered as chemical rate determining step (RDS) for the ORR. It was also found that all the Pd-Cu alloys exhibited better electrocatalystic performances for the ORR than Pd or Cu alone. From the polarisation of the ORR in 0,1 M HClO4 it was shown that the curve of the Pd electrode was shifted to the lower potentials than those of the Pd-Cu alooys. In addition, the variation of the kinetic current of the ORR at 0,6 V vs. SCE (0,841 V vs. RHE) on the Pd-Cu alloys with the composition of in Cu content exhibited a volcano-shape. (Abstract shortened by UMI.)

Light-adaptation of photosystem II is mediated by the plastoquinone pool.

PubMed

Ahrling, Karin A; Peterson, Sindra

2003-07-01

During the first few enzymatic turnovers after dark-adaptation of photosystem II (PSII), the relaxation rate of the EPR signals from the Mn cluster and Y(D)(*) are significantly enhanced. This light-adaptation process has been suggested to involve the appearance of a new paramagnet on the PSII donor side [Peterson, S., Ahrling, K., Högblom, J., and Styring, S. (2003) Biochemistry 42, 2748-2758]. In the present study, a correlation is established between the observed relaxation enhancement and the redox state of the quinone pool. It is shown that the addition of quinol to dark-adapted PSII membrane fragments induces relaxation enhancement already after a single oxidation of the Mn, comparable to that observed after five oxidations in samples with quinones (PPBQ or DQ) added. The saturation behavior of Y(D)(*) revealed that with quinol added in the dark, a single flash was necessary for the relaxation enhancement to occur. The quinol-induced relaxation enhancement of PSII was also activated by illumination at 200 K. Whole thylakoids, with no artificial electron acceptor present but with an intact plastoquinone pool, displayed the same relaxation enhancement on the fifth flash as membrane fragments with exogenous quinones present. We conclude that (i) reduction of the quinone pool induces the relaxation enhancement of the PSII donor-side paramagnets, (ii) light is required for the quinol to effect the relaxation enhancement, and (iii) light-adaptation occurs in the intact thylakoid system, when the endogenous plastoquinone pool is gradually reduced by PSII turnover. It seems clear that a species on the PSII donor side is reduced by the quinol, to become a potent paramagnetic relaxer. On the basis of XANES reports, we suggest that this species may be the Mn ions not involved in the cyclic redox changes of the oxygen-evolving complex.

Metal molybdate nanorods as non-precious electrocatalysts for the oxygen reduction

NASA Astrophysics Data System (ADS)

Wu, Tian; Zhang, Lieyu

2015-12-01

Development of non-precious electrocatalysts with applicable electrocatalytic activity towards the oxygen reduction reaction (ORR) is important to fulfill broad-based and large-scale applications of metal/air batteries and fuel cells. Herein, nickel and cobalt molybdates with uniform nanorod morphology are synthesized using a facile one-pot hydrothermal method. The ORR activity of the prepared metal molybdate nanorods in alkaline media are investigated by using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperomety in rotating disk electrode (RDE) techniques. The present study suggests that the prepared metal molybdate nanorods exhibit applicable electrocatalytic activities towards the ORR in alkaline media, promising the applications as non-precious cathode in fuel cells and metal-air batteries.

Metal-phthalocyanine functionalized carbon nanotubes as catalyst for the oxygen reduction reaction: A theoretical study

NASA Astrophysics Data System (ADS)

Orellana, Walter

2012-07-01

The covalent functionalization of metallic single-walled carbon nanotubes (CNTs) with transition metal phthalocyanines (MPc, with M = Mn, Fe and Co) are addressed by density functional calculations. The CNT-MPc catalytic activity toward the oxygen reduction reaction (ORR) is investigated through the O2 stretching frequency adsorbed on the phthalocyanine metal center. We find better reduction abilities when the CNT functionalization occurs through sp2-like bonds. Multiple stable-spin states for the M-O2 adduct are also found for M = Mn and Fe, suggesting higher ORR rates. The CNT-MPc complexes show metallic characteristics, suggesting favorable conditions to work as ORR cathode catalysts in fuel cells.

Enhancing Electrocatalytic Performance of Bifunctional Cobalt–Manganese-Oxynitride Nanocatalysts on Graphene

DOE PAGES

Li, Yang; Kuttiyiel, Kurian A.; Wu, Lijun; ...

2016-11-21

In this paper, we report the synthesis and characterization of graphenesupported cobalt–manganese-oxynitride nanocatalysts (CoMnON/G) as bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). A nitriding treatment of spinel compound CoMnO increased the ORR activity considerably, and the most active material catalyzed the ORR with only a 30 mV half-wave potential difference from the commercial carbon-supported platinum (Pt/C) in alkaline media. In addition to high activity, the catalyst also exhibited an intrinsic stability that outperformed Pt/C. Finally, an appropriately designed nitridation thus facilitates new directions for developing active and durable non-precious-metal oxynitride electocatalysts.

Enhancement of Platinum Cathode Catalysis by Addition of Transition Metals

ERIC Educational Resources Information Center

Duong, Hung Tuan

2009-01-01

The sluggish kinetics of oxygen reduction reaction (ORR) contributes significantly to the loss of cathode overpotential in fuel cells, thus requiring high loadings of platinum (Pt), which is an expensive metal with limited supply. However, Pt and Pt-based alloys are still the best available electrocatalysts for ORR thus far. The research presented…

Intra- to Multi-Decadal Temperature Variability over the Continental United States: 1896-2012

USDA-ARS?s Scientific Manuscript database

The Optimal Ranking Regime (ORR) method was used to identify intra- to multi-decadal (IMD) time windows containing significant ranking sequences in U.S. climate division temperature data. The simplicity of the ORR procedure’s output – a time series’ most significant non-overlapping periods of high o...

Optimal ranking regime analysis of intra- to multidecadal U.S. climate variability. Part I: Temperature

USDA-ARS?s Scientific Manuscript database

The Optimal Ranking Regime (ORR) method was used to identify intra- to multi-decadal (IMD) time windows containing significant ranking sequences in U.S. climate division temperature data. The simplicity of the ORR procedure’s output – a time series’ most significant non-overlapping periods of high o...

A Facile Synthesis of Nitrogen-Doped Highly Porous Carbon Nanoplatelets: Efficient Catalysts for Oxygen Electroreduction

NASA Astrophysics Data System (ADS)

Zhang, Yaqing; Zhang, Xianlei; Ma, Xiuxiu; Guo, Wenhui; Wang, Chunchi; Asefa, Tewodros; He, Xingquan

2017-02-01

The oxygen reduction reaction (ORR) is of great importance for various renewable energy conversion technologies such as fuel cells and metal-air batteries. Heteroatom-doped carbon nanomaterials have proven to be robust metal-free electrocatalysts for ORR in the above-mentioned energy devices. Herein, we demonstrate the synthesis of novel highly porous N-doped carbon nanoplatelets (N-HPCNPs) derived from oatmeal (or a biological material) and we show the materials’ high-efficiency as electrocatalyst for ORR. The obtained N-HPCNPs hybrid materials exhibit superior electrocatalytic activities towards ORR, besides excellent stability and good methanol tolerance in both basic and acidic electrolytes. The unique nanoarchitectures with rich micropores and mesopores, as well as the high surface area-to-volume ratios, present in the materials significantly increase the density of accessible catalytically active sites in them and facilitate the transport of electrons and electrolyte within the materials. Consequently, the N-HPCNPs catalysts hold a great potential to serve as low-cost and highly efficient cathode materials in direct methanol fuel cells (DMFCs).

Toxics Release Inventory Expansion Rule Phase 3 (TRI-P3)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, R.A.; Saunders, A.D.; Worley, G.G.

1998-09-01

The ORR [East Tennessee Technology Park (ETTP), Y-12 Plant, and Oak Ridge National Laboratory (ORNL)] is considered a single facility for reporting by the DOE prime contractors. The processing, manufacturing, or "otherwise use" Section313 chemicals are combined to determine TRI reportability. Such is the case with lead metal, which is one of two chemicals for which reportin~ forms were prepared in this pilot study (Task 2;1. The lead shop at ORNL exceeded the reporting threshold, causing a lead activity at a Y-1 2 machine shop and lead in waste at ETTP to be reportable. TRI-P3 report preparation time for leadmore » totaled 36.5 hours. The second chemical investigated and reported (chromium) also required nearly a man-week for report preparation and documentation by experienced TRI personnel. The ORR TRI report typically includes about six chemicals, so an estimate of the TRI-P3 incremental reporting burden for ORR would be six weeks for experienced personnel axI d two/three man-months for first-time ORR preparers.« less

Tungsten carbide encapsulated in nitrogen-doped carbon with iron/cobalt carbides electrocatalyst for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Zhang, Jie; Chen, Jinwei; Jiang, Yiwu; Zhou, Feilong; Wang, Gang; Wang, Ruilin

2016-12-01

This work presents a type of hybrid catalyst prepared through an environmental and simple method, combining a pyrolysis of transition metal precursors, a nitrogen-containing material, and a tungsten source to achieve a one-pot synthesis of N-doping carbon, tungsten carbides, and iron/cobalt carbides (Fe/Co/WC@NC). The obtained Fe/Co/WC@NC consists of uniform Fe3C and Co3C nanoparticles encapsulated in graphitized carbon with surface nitrogen doping, closely wrapped around a plate-like tungsten carbide (WC) that functions as an efficient oxygen reduction reaction (ORR) catalyst. The introduction of WC is found to promote the ORR activity of Fe/Co-based carbide electrocatalysts, which is attributed to the synergistic catalysts of WC, Fe3C, and Co3C. Results suggest that the composite exhibits comparable electrocatalytic activity, higher durability, and ability for methanol tolerance compared with commercial Pt/C for ORR in alkaline electrolyte. These advantages make Fe/Co/WC@NC a promising ORR electrocatalyst and a cost-effective alternative to Pt/C for practical application as fuel cell.

Correlating two-photon excited fluorescence imaging of breast cancer cellular redox state with seahorse flux analysis of normalized cellular oxygen consumption

NASA Astrophysics Data System (ADS)

Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.

2016-06-01

Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.

Some reflections on the understanding of the oxygen reduction reaction at Pt(111)

PubMed Central

Gómez-Marín, Ana M; Rizo, Ruben

2013-01-01

Summary The oxygen reduction reaction (ORR) is a pivotal process in electrochemistry. Unfortunately, after decades of intensive research, a fundamental knowledge about its reaction mechanism is still lacking. In this paper, a global and critical view on the most important experimental and theoretical results regarding the ORR on Pt(111) and its vicinal surfaces, in both acidic and alkaline media, is taken. Phenomena such as the ORR surface structure sensitivity and the lack of a reduction current at high potentials are discussed in the light of the surface oxidation and disordering processes and the possible relevance of the hydrogen peroxide reduction and oxidation reactions in the ORR mechanism. The necessity to build precise and realistic reaction models, which are deducted from reliable experimental results that need to be carefully taken under strict working conditions is shown. Therefore, progress in the understanding of this important reaction on a molecular level, and the choice of the right approach for the design of the electrocatalysts for fuel-cell cathodes is only possible through a cooperative approach between theory and experiments. PMID:24455454

Some reflections on the understanding of the oxygen reduction reaction at Pt(111).

PubMed

Gómez-Marín, Ana M; Rizo, Ruben; Feliu, Juan M

2013-12-27

The oxygen reduction reaction (ORR) is a pivotal process in electrochemistry. Unfortunately, after decades of intensive research, a fundamental knowledge about its reaction mechanism is still lacking. In this paper, a global and critical view on the most important experimental and theoretical results regarding the ORR on Pt(111) and its vicinal surfaces, in both acidic and alkaline media, is taken. Phenomena such as the ORR surface structure sensitivity and the lack of a reduction current at high potentials are discussed in the light of the surface oxidation and disordering processes and the possible relevance of the hydrogen peroxide reduction and oxidation reactions in the ORR mechanism. The necessity to build precise and realistic reaction models, which are deducted from reliable experimental results that need to be carefully taken under strict working conditions is shown. Therefore, progress in the understanding of this important reaction on a molecular level, and the choice of the right approach for the design of the electrocatalysts for fuel-cell cathodes is only possible through a cooperative approach between theory and experiments.

Surface-oxidized cobalt phosphide used as high efficient electrocatalyst in activated carbon air-cathode microbial fuel cell

NASA Astrophysics Data System (ADS)

Yang, Tingting; Wang, Zhong; Li, Kexun; Liu, Yi; Liu, Di; Wang, Junjie

2017-09-01

Herein, we report a simplistic method to fabricate the surface-oxidized cobalt phosphide (CoP) nanocrystals (NCs), which is used as electrocatalyst for oxygen reduction reaction (ORR) in microbial fuel cell (MFC) for the first time. The corallite-like CoP NCs are successfully prepared by a hydrothermal reaction following a phosphating treatment in N2 atmosphere. When used as an ORR catalyst, cobalt phosphide shows comparable onset potential, inferior resistance, as well as a small Tafel slope with long-term stability in neutral media. The maximum power density of MFC embellished with 10% CoP reached 1914.4 ± 59.7 mW m-2, which is 108.5% higher than the control. The four-electron pathway, observed by the RDE, plays a crucial role in electrochemical catalytic activity. In addition, material characterizations indicate that the surface oxide layer (CoOx) around the metallic CoP core is important and beneficial for ORR. Accordingly, it can be expected that the as-synthesized CoP will be a promising candidate of the non-precious metal ORR electrocatalysts for electrochemical energy applications.

Comparison of iridium- and ruthenium-based, Pt-surface-enriched, nanosize catalysts for the oxygen-reduction reaction

NASA Astrophysics Data System (ADS)

Kaplan, D.; Goor, M.; Alon, M.; Tsizin, S.; Burstein, L.; Rosenberg, Y.; Popov, I.; Peled, E.

2016-02-01

Pt-surface-enriched nanosize catalysts (Pt-SENS catalysts) with ruthenium and iridium cores, supported on XC72, were synthesized and characterized. The structure and composition of the catalysts are determined by Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Scanning Transmission Electron Microscopy (STEM) and X-Ray Diffraction (XRD). Electrochemical characterization tests, including oxygen-reduction-catalysis activity and durability studies of catalysts are performed with the use of cyclic-voltammetry and rotating-disk-electrode (RDE) techniques at room temperature. The ORR activity of the homemade catalysts is also compared to ORR activity of commercial 50%Pt/C catalyst. It is determined that the Ir-based catalyst (Pt/Ir/XC72) shows higher ORR activity in terms of A g-1 of Pt (at 0.85 V vs. RHE) than the Ru-based catalyst (Pt/Ru/XC72) and the commercial 50%Pt/C. The Ru-based catalyst shows similar ORR activity in terms of A g-1 of Pt, to that of the commercial 50%Pt/C, but with much lower durability.

Status report on the geology of the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatcher, R.D. Jr.; Lemiszki, P.J.; Foreman, J.L.

1992-10-01

This report provides an introduction to the present state of knowledge of the geology of the Oak Ridge Reservation (ORR) and a cursory introduction to the hydrogeology. An important element of this work is the construction of a modern detailed geologic map of the ORR (Plate 1), which remains in progress. An understanding of the geologic framework of the ORR is essential to many current and proposed activities related to land-use planning, waste management, environmental restoration, and waste remediation. Therefore, this report is also intended to convey the present state of knowledge of the geologic and geohydrologic framework of themore » ORR and vicinity and to present some of the available data that provide the basic framework for additional geologic mapping, subsurface geologic, and geohydrologic studies. In addition, some recently completed, detailed work on soils and other surficial materials is included because of the close relationships to bedrock geology and the need to recognize the weathered products of bedrock units. Weathering processes also have some influence on hydrologic systems and processes at depth.« less

Remedial investigation/feasibility study of the Clinch River/Poplar Creek operable unit. Volume 1: Main text

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This report presents the findings of an investigation into contamination of the Clinch River and Poplar Creek near the US Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) in eastern Tennessee. For more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities at the ORR. In 1989, the ORR was placed on the National Priorities List (NPL), established and maintained under the federal Comprehensive environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Under CERCLA, NPL sites must be investigated to determine the nature and extentmore » of contamination at the site, assess the risk to human health and the environment posed by the site, and, if necessary, identify feasible remedial alternatives that could be used to clean the site and reduce risk. To facilitate the overall environmental restoration effort at the ORR, CERCLA activities are being implemented individually as distinct operable units (OUs). This document is the combined Remedial Investigation and Feasibility Study Report for the Clinch River/Poplar Creek OU.« less

Synthesis of an efficient heteroatom-doped carbon electro-catalyst for oxygen reduction reaction by pyrolysis of protein-rich pulse flour cooked with SiO2 nanoparticles.

PubMed

Gokhale, Rohan; Unni, Sreekuttan M; Puthusseri, Dhanya; Kurungot, Sreekumar; Ogale, Satishchandra

2014-03-07

Development of a highly durable, fuel-tolerant, metal-free electro-catalyst for oxygen reduction reaction (ORR) is essential for robust and cost-effective Anion Exchange Membrane Fuel Cells (AEMFCs). Herein, we report the development of a nitrogen-doped (N-doped) hierarchically porous carbon-based efficient ORR electrocatalyst from protein-rich pulses. The process involves 3D silica nanoparticle templating of the pulse flour(s) followed by their double pyrolysis. The detailed experiments are performed on gram flour (derived from chickpeas) without any in situ/ex situ addition of dopants. The N-doped porous carbon thus generated shows remarkable electrocatalytic activity towards ORR in the alkaline medium. The oxygen reduction on this material follows the desired 4-electron transfer mechanism involving the direct reduction pathway. Additionally, the synthesized carbon catalyst also exhibits good electrochemical stability and fuel tolerance. The results are also obtained and compared with the case of soybean flour having higher nitrogen content to highlight the significance of different parameters in the ORR catalyst performance.

Cations in Octahedral Sites: A Descriptor for Oxygen Electrocatalysis on Transition-Metal Spinels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Chao; Feng, Zhenxing; Scherer, Günther G.

2017-04-10

Exploring efficient and low-cost electrocatalysts for the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER) is critical for developing renewable energy technologies such as fuel cells, metal–air batteries, and water electrolyzers. A rational design of a catalyst can be guided by identifying descriptors that determine its activity. Here, a descriptor study on the ORR/OER of spinel oxides is presented. With a series of MnCo2O4, the Mn in octahedral sites is identified as an active site. This finding is then applied to successfully explain the ORR/OER activities of other transition-metal spinels, including MnxCo3-xO4 (x = 2, 2.5, 3), LixMn2O4 (x = 0.7,more » 1), XCo2O4 (X = Co, Ni, Zn), and XFe2O4 (X = Mn, Co, Ni). A general principle is concluded that the eg occupancy of the active cation in the octahedral site is the activity descriptor for the ORR/OER of spinels, consolidating the role of electron orbital filling in metal oxide catalysis.« less

Transforming waste biomass with an intrinsically porous network structure into porous nitrogen-doped graphene for highly efficient oxygen reduction.

PubMed

Zhou, Huang; Zhang, Jian; Amiinu, Ibrahim Saana; Zhang, Chenyu; Liu, Xiaobo; Tu, Wenmao; Pan, Mu; Mu, Shichun

2016-04-21

Porous nitrogen-doped graphene with a very high surface area (1152 m(2) g(-1)) is synthesized by a novel strategy using intrinsically porous biomass (soybean shells) as a carbon and nitrogen source via calcination and KOH activation. To redouble the oxygen reduction reaction (ORR) activity by tuning the doped-nitrogen content and type, ammonia (NH3) is injected during thermal treatment. Interestingly, this biomass-derived graphene catalyst exhibits the unique properties of mesoporosity and high pyridine-nitrogen content, which contribute to the excellent oxygen reduction performance. As a result, the onset and half-wave potentials of the new metal-free non-platinum catalyst reach -0.009 V and -0.202 V (vs. SCE), respectively, which is very close to the catalytic activity of the commercial Pt/C catalyst in alkaline media. Moreover, our catalyst has a higher ORR stability and stronger CO and CH3OH tolerance than Pt/C in alkaline media. Importantly, in acidic media, the catalyst also exhibits good ORR performance and higher ORR stability compared to Pt/C.

Relationship among side channels, fish assemblages, and environmental gradients in the unimpounded Upper Mississippi River

USGS Publications Warehouse

Barko, V.A.; Herzog, D.P.

2003-01-01

We analyzed fish abundance and environmental data collected over nine years from six side channels of the unimpounded upper Mississippi River between river km 46.7 and 128.7. A partial canonical correspondence analysis revealed differences in fish assemblages and environmental factors correlated with the six side channels. Fishes correlated with open side channels represented large river species tolerant of current and/or turbidity. Fishes correlated with closed side channels represented assemblages preferring either moderate to low turbidity/current or pools.

Co@Pd core-shell nanoparticles embedded in nitrogen-doped porous carbon as dual functional electrocatalysts for both oxygen reduction and hydrogen evolution reactions.

PubMed

Yang, Hongyu; Tang, Zhenghua; Wang, Kai; Wu, Wen; Chen, Yinghuan; Ding, Zhaoqing; Liu, Zhen; Chen, Shaowei

2018-05-21

Developing efficient bi-functional electrocatalysts for both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is crucial for producing hydrogen and utilizing hydrogen effectively to promote electrochemical energy storage in proton membrane exchange fuel cells (PEMFCs). Herein, we report Co@Pd core-shell nanoparticles encapsulated in porous carbon derived from zeolitic imidazolate framework 67 (ZIF-67) for both ORR and HER. The controlled pyrolysis of ZIF-67 can lead to the formation of Co nanoparticles encapsulated in nitrogen-doped porous carbon (Co NC), which subsequently underwent galvanic replacement with Na 2 PdCl 4 to form Co@Pd core-shell nanoparticles embedded in nitrogen-doped porous carbon (Co@Pd NC). The Co@Pd NC exhibited outperformance in ORR and HER than commercial Pd/C, as manifested by more positive onset potential and larger diffusion-limited current density in ORR tests, as well as a small overpotential to drive a current density of 10 mA cm -2 , and much lower Tafel slope in HER tests. It also demonstrated more robust long-term stability than commercial Pd/C for both ORR and HER. Multiple techniques inter-confirmed that the Pd loading in the sample was very low. The findings can pave a path for fabricating a core-shell structured nanocomposite with ultralow noble metal usage as a bifunctional catalyst for electrochemical energy storage and conversion with high-efficiency and remarkable longevity. Copyright © 2018 Elsevier Inc. All rights reserved.

A novel metal organic framework-derived carbon-based catalyst for oxygen reduction reaction in a microbial fuel cell

NASA Astrophysics Data System (ADS)

Zhang, Lihua; Hu, Yongyou; Chen, Junfeng; Huang, Wantang; Cheng, Jianhua; Chen, Yuancai

2018-04-01

To improve the power generation of microbial fuel cell (MFC), the cathode is modified to increase its oxygen reduction reaction (ORR) activity by using a Cu, N-incorporated carbon-based material as catalyst, which obtained from pyrolyzing ORR active Cu (II)-based metal organic framework (MOF; Cu-bipy-BTC, bipy = 2,2‧-bipyridine, BTC = 1,3,5-tricarboxylate). MOF-800 (the product of pyrolyzing Cu-bipy-BTC at 800 °C) shows porous structure with micropores ranging from 0.5 to 1.3 nm and mesopores ranging from 27 to 46 nm. It also exhibits improved ORR electrocatalytic activity with a higher current density of -3.06 mA cm-2 compared to Cu-bipy-BTC. Moreover, the charge transfer resistance of MOF-800 cathode (1.38 Ω) is much smaller than that of Cu-bipy-BTC cathode (176.8 Ω). A maximum power density of 326 ± 11 mW m-2 is achieved by MOF-800-MFC, which is 2.6 times of that of Cu-bipy-BTC-MFC and comparable with Pt/C-MFC (402 ± 17 mW m-2). The results imply the enhancements of ORR catalytic activity and electrical conductivity of MOF-800 are due to the enhanced porous structure and abundant active sites (C-N, Cu-Nχ), which result in the improved power generation of MFC. This study provides technical and theoretical validation for the MFC performance improvement by ORR active MOF-derived catalysts modified cathodes.

Comparative Study of the ORR Activity and Stability of Pt and PtM (M = Ni, Co, Cr, Pd) Supported on Polyaniline/Carbon Nanotubes in a PEM Fuel Cell.

PubMed

Kaewsai, Duanghathai; Hunsom, Mali

2018-05-04

The oxygen reduction reaction (ORR) activity and stability of platinum (Pt) and PtM (M = Ni, Co, Cr, Pd) supported on polyaniline/carbon nanotube (PtM/PANI-CNT) were explored and compared with the commercial Pt/C catalyst (ETEK). The Pt/PANI-CNT catalyst exhibited higher ORR activity and stability than the commercial Pt/C catalyst even though it had larger crystallite/particle sizes, lower catalyst dispersion and lower electrochemical surface area (ESA), probably because of its high electrical conductivity. The addition of second metal (M) enhanced the ORR activity and stability of the Pt/PANI-CNT catalyst, because the added M induced the formation of a PtM alloy and shifted the d -band center to downfield, leading to a weak chemical interaction between oxygenated species and the catalyst surface and, therefore, affected positively the catalytic activity. Among all the tested M, the addition of Cr was optimal. Although it improved the ORR activity of the Pt/PANI-CNT catalyst slightly less than that of Pd (around 4.98%) in low temperature (60 °C)/pressure (1 atm abs), it reduced the ESA loss by around 14.8% after 1000 cycles of repetitive cyclic voltammetry (CV). In addition, it is cheaper than Pd metal. Thus, Cr was recommended as the second metal to alloy with Pt on the PANI-CNT support.

Mechanism of oxygen reduction reaction on Pt(111) in alkaline solution: Importance of chemisorbed water on surface

DOE PAGES

Liu, Shizhong; White, Michael G.; Liu, Ping

2016-06-30

Here, we report a detailed mechanistic study of the oxygen reduction reaction (ORR) on Pt(111) in alkaline solution, combining density functional theory and kinetic Monte Carlo simulations. A complex reaction network including four possible pathways via either 2e – or 4e – transfer is established and is able to reproduce the experimental measured polarization curve at both low- and high-potential regions. Our results show that it is essential to account for solvation by water and the dynamic coverage of *OH to describe the reaction kinetics well. In addition, a chemisorbed water (*H 2O)-mediated mechanism including 4e – transfers is identified,more » where the reduction steps via *H 2O on the surface are potential-independent and only the final removal of *OH from the surface in the form of OH –(aq) contributes to the current. For the ORR in alkaline solutions, such a mechanism is more competitive than the associative and dissociative mechanisms typically used to describe the ORR in acid solution. Finally, *OH and **O 2 intermediates are found to be critically important for tuning the ORR activity of Pt in alkaline solution. To enhance the activity, the binding of Pt should be tuned in such a way that *OH binding is weak enough to release more surface sites under working conditions, while **O 2 binding is strong enough to enable the ORR via the 4e – transfer mechanism.« less

Geochemistry and Mineralogy of Western Australian Salt Lake Sediments: Implications for Meridiani Planum on Mars.

PubMed

Ruecker, A; Schröder, C; Byrne, J; Weigold, P; Behrens, S; Kappler, A

2016-07-01

Hypersaline lakes are characteristic for Western Australia and display a rare combination of geochemical and mineralogical properties that make these lakes potential analogues for past conditions on Mars. In our study, we focused on the geochemistry and mineralogy of Lake Orr and Lake Whurr. While both lakes are poor in organic carbon (<1%), the sediments' pH values differ and range from 3.8 to 4.8 in Lake Orr and from 5.4 to 6.3 in Lake Whurr sediments. Lake Whurr sediments were dominated by orange and red sediment zones in which the main Fe minerals were identified as hematite, goethite, and tentatively jarosite and pyrite. Lake Orr was dominated by brownish and blackish sediments where the main Fe minerals were goethite and another paramagnetic Fe(III)-phase that could not be identified. Furthermore, a likely secondary Fe(II)-phase was observed in Lake Orr sediments. The mineralogy of these two salt lakes in the sampling area is strongly influenced by events such as flooding, evaporation, and desiccation, processes that explain at least to some extent the observed differences between Lake Orr and Lake Whurr. The iron mineralogy of Lake Whurr sediments and the high salinity make this lake a suitable analogue for Meridiani Planum on Mars, and in particular the tentative identification of pyrite in Lake Whurr sediments has implications for the interpretation of the Fe mineralogy of Meridiani Planum sediments. Western Australia-Salt lakes-Jarosite-Hematite-Pyrite-Mars analogue. Astrobiology 16, 525-538.

Comparative Study of the ORR Activity and Stability of Pt and PtM (M = Ni, Co, Cr, Pd) Supported on Polyaniline/Carbon Nanotubes in a PEM Fuel Cell

PubMed Central

Kaewsai, Duanghathai; Hunsom, Mali

2018-01-01

The oxygen reduction reaction (ORR) activity and stability of platinum (Pt) and PtM (M = Ni, Co, Cr, Pd) supported on polyaniline/carbon nanotube (PtM/PANI-CNT) were explored and compared with the commercial Pt/C catalyst (ETEK). The Pt/PANI-CNT catalyst exhibited higher ORR activity and stability than the commercial Pt/C catalyst even though it had larger crystallite/particle sizes, lower catalyst dispersion and lower electrochemical surface area (ESA), probably because of its high electrical conductivity. The addition of second metal (M) enhanced the ORR activity and stability of the Pt/PANI-CNT catalyst, because the added M induced the formation of a PtM alloy and shifted the d-band center to downfield, leading to a weak chemical interaction between oxygenated species and the catalyst surface and, therefore, affected positively the catalytic activity. Among all the tested M, the addition of Cr was optimal. Although it improved the ORR activity of the Pt/PANI-CNT catalyst slightly less than that of Pd (around 4.98%) in low temperature (60 °C)/pressure (1 atm abs), it reduced the ESA loss by around 14.8% after 1000 cycles of repetitive cyclic voltammetry (CV). In addition, it is cheaper than Pd metal. Thus, Cr was recommended as the second metal to alloy with Pt on the PANI-CNT support. PMID:29734719

Understanding the Dynamics of the South Indian Ocean Sea Surface Salinity Maximum Pool From Argo, Rama, Aquarius, SMOS & Other Satellites

NASA Astrophysics Data System (ADS)

Menezes, V. V.; Phillips, H. E.

2016-02-01

Subtropical salinity maximum regions are particularly important because the salty subtropical underwater (STW) is formed by subduction of surface waters in these areas. In all oceans, the STW is transported equatorward from the formation region and are tightly related to the Subtropical-Tropical Cell. In the South Indian Ocean (SIO), the salinity maximum pool is further poleward (25S-38S) and eastward (60E-120E). It significantly impacts the circulation of the eastern basin, because the STW forms a strong haline front with the fresh Indonesian Throughflow waters. This haline front overwhelms the temperature contribution establishing the eastward Eastern Gyral Current, an important upstream source for the Leeuwin Current. In the present work, we analyze the variability of the SSS maximum pool using Aquarius and SMOS satellites, an Argo gridded product and the RAMA mooring located at 25S-100E. OAFLUX, 3B42 TRMM, Ascat/Quikscat winds and OSCAR products complement this study. The salinity maximum pool has a strong seasonal cycle of contraction (min in Oct) and expansion (max in April), and most of this variation occurs in the pool poleward side. Advection and entrainment control the contraction, while expansion is due to atmospheric forcing (E-P). From 2004 to 2014, a clear reduction in the pool area is identified, which might be related to a decadal variability. In this case, the variation is in the equatorward side of the pool. Processes controlling this long-term variability are being investigated.

Long-term safety and efficacy of vismodegib in patients with advanced basal cell carcinoma: final update of the pivotal ERIVANCE BCC study.

PubMed

Sekulic, Aleksandar; Migden, Michael R; Basset-Seguin, Nicole; Garbe, Claus; Gesierich, Anja; Lao, Christopher D; Miller, Chris; Mortier, Laurent; Murrell, Dedee F; Hamid, Omid; Quevedo, Jorge F; Hou, Jeannie; McKenna, Edward; Dimier, Natalie; Williams, Sarah; Schadendorf, Dirk; Hauschild, Axel

2017-05-16

In the primary analysis of the ERIVANCE BCC trial, vismodegib, the first US Food and Drug Administration-approved Hedgehog pathway inhibitor, showed objective response rates (ORRs) by independent review facility (IRF) of 30% and 43% in metastatic basal cell carcinoma (mBCC) and locally advanced BCC (laBCC), respectively. ORRs by investigator review were 45% (mBCC) and 60% (laBCC). Herein, we present long-term safety and final investigator-assessed efficacy results in patients with mBCC or laBCC. One hundred four patients with measurable advanced BCC received oral vismodegib 150 mg once daily until disease progression or intolerable toxicity. The primary end point was IRF-assessed ORR. Secondary end points included ORR, duration of response (DOR), progression-free survival, overall survival (OS), and safety. At data cutoff (39 months after completion of accrual), 8 patients were receiving the study drug (69 patients in survival follow-up). Investigator-assessed ORR was 48.5% in the mBCC group (all partial responses) and 60.3% in the laBCC group (20 patients had complete response and 18 patients had partial response). ORRs were comparable across patient subgroups, including aggressive histologic subtypes (eg, infiltrative BCC). Median DOR was 14.8 months (mBCC) and 26.2 months (laBCC). Median OS was 33.4 months in the mBCC cohort and not estimable in the laBCC cohort. Adverse events remained consistent with clinical experience. Thirty-three deaths (31.7%) were reported; none were related to vismodegib. This long-term update of the ERIVANCE BCC trial demonstrated durability of response, efficacy across patient subgroups, and manageable long-term safety of vismodegib in patients with advanced BCC. This study was registered prospectively with Clinicaltrials.gov , number NCT00833417 on January 30, 2009.

The Opioid Rotation Ratio of Hydrocodone to Strong Opioids in Cancer Patients

PubMed Central

Yennurajalingam, Sriram; Desai, Hem; Reddy, Suresh; de la Cruz, Maxine; Wu, Jimin; Liu, Diane; Rodriguez, Eden Mae; Waletich, Jessica; Shin, Seong Hoon; Gayle, Vicki; Patel, Pritul; Dalal, Shalini; Vidal, Marieberta; Tanco, Kimberson; Arthur, Joseph; Tallie, Kimmie; Williams, Janet; Silvestre, Julio; Bruera, Eduardo

2014-01-01

Purpose. Cancer pain management guidelines recommend initial treatment with intermediate-strength analgesics such as hydrocodone and subsequent escalation to stronger opioids such as morphine. There are no published studies on the process of opioid rotation (OR) from hydrocodone to strong opioids in cancer patients. Our aim was to determine the opioid rotation ratio (ORR) of hydrocodone to morphine equivalent daily dose (MEDD) in cancer outpatients. Patients and Methods. We reviewed the records of consecutive patient visits at our supportive care center in 2011–2012 for OR from hydrocodone to stronger opioids. Data regarding demographics, Edmonton Symptom Assessment Scale (ESAS), and MEDD were collected from patients who returned for follow-up within 6 weeks. Linear regression analysis was used to estimate the ORR between hydrocodone and MEDD. Successful OR was defined as 2-point or 30% reduction in the pain score and continuation of the new opioid at follow-up. Results. Overall, 170 patients underwent OR from hydrocodone to stronger opioid. The median age was 59 years, and 81% had advanced cancer. The median time between OR and follow-up was 21 days. We found 53% had a successful OR with significant improvement in the ESAS pain and symptom distress scores. In 100 patients with complete OR and no worsening of pain at follow-up, the median ORR from hydrocodone to MEDD was 1.5 (quintiles 1–3: 0.9–2). The ORR was associated with hydrocodone dose (r = −.52; p < .0001) and was lower in patients receiving ≥40 mg of hydrocodone per day (p < .0001). The median ORR of hydrocodone to morphine was 1.5 (n = 44) and hydrocodone to oxycodone was 0.9 (n = 24). Conclusion. The median ORR from hydrocodone to MEDD was 1.5 and varied according to hydrocodone dose. PMID:25342316

Do Surrogate Endpoints Better Correlate with Overall Survival in Studies That Did Not Allow for Crossover or Reported Balanced Postprogression Treatments? An Application in Advanced Non-Small Cell Lung Cancer.

PubMed

Hashim, Mahmoud; Pfeiffer, Boris M; Bartsch, Robert; Postma, Maarten; Heeg, Bart

2018-01-01

In previous studies, correlation between overall survival (OS) and surrogate endpoints like objective response rate (ORR) or progression-free survival (PFS) in advanced non-small cell lung cancer (NSCLC) was poor. This can be biased by crossover and postprogression treatments. To evaluate the relationship between these two surrogate endpoints and OS in advanced NSCLC studies that did not allow for crossover or reported balanced post-progression treatments. A systematic review in patients with advanced NSCLC receiving second- and further-line therapy was performed. The relationship between the absolute difference in ORR or median PFS (mPFS) and the absolute difference in median OS (mOS) was assessed using the correlation coefficient (R) and weighted regression models. The analysis was repeated in predefined data cuts based on crossover and balance of postprogression treatments. When the upper limit of R's 95% confidence interval (CI) was more than 0.7, the surrogate threshold effect (STE) was estimated. In total, 146 randomized clinical trials (43,061 patients) were included. The mean ORR, mPFS, and mOS were 12.2% ± 11.2%, 3.2 ± 1.3 months, and 9.6 ± 4.1 months, respectively. The correlation coefficients of ORR and mPFS were 0.181 (95% CI 0.016-0.337) and 0.254 (95% CI 0.074-0.418), respectively, with mOS. Nevertheless, in trials that did not allow crossover and reported balanced postprogression treatments, the correlation coefficients of ORR and mPFS were 0.528 (95% CI 0.081-0.798) and 0.778 (95% CI 0.475-0.916), respectively, with mOS. On the basis of STE estimation, in trials showing significant treatment effect size of 41.0% or more ORR or 4.15 or more mPFS months, OS benefit can be expected with sufficient certainty. Crossover and postprogression treatments may bias the relationship between surrogate endpoints and OS. Presented STE calculation can be used to interpret treatment effect on either ORR or PFS when used as primary endpoints. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Recent advances in the design of tailored nanomaterials for efficient oxygen reduction reaction

DOE PAGES

Lv, Haifeng; Li, Dongguo; Strmcnik, Dusan; ...

2016-04-11

In the past decade, polymer electrolyte membrane fuels (PEMFCs) have been evaluated for both automotive and stationary applications. One of the main obstacles for large scale commercialization of this technology is related to the sluggish oxygen reduction reaction that takes place on the cathode side of fuel cell. Consequently, ongoing research efforts are focused on the design of cathode materials that could improve the kinetics and durability. Majority of these efforts rely on novel synthetic approaches that provide control over the structure, size, shape and composition of catalytically active materials. This article highlights the most recent advances that have beenmore » made to tailor critical parameters of the nanoscale materials in order to achieve more efficient performance of the oxygen reduction reaction (ORR).« less

"Malama I Ka 'Aina, Sustainability": Learning from Hawai'i's Displaced Place and Culture-Based Science Standard

ERIC Educational Resources Information Center

Chinn, Pauline W. U.

2011-01-01

This response to Mitchell and Mueller's "A philosophical analysis of David Orr's theory of ecological literacy" comments on their critique of Orr's use of the phrase "ecological crisis" and what I perceive as their conflicting views of "crisis." I present my views on ecological crisis informed by standpoint theory and…

BiOCl micro-assembles consisting of ultrafine nanoplates: A high performance electro-catalyst for air electrode of Al-air batteries

NASA Astrophysics Data System (ADS)

Yuan, Jinlan; Wang, Jin; She, Yiyi; Hu, Jing; Tao, Pengpeng; Lv, Fucong; Lu, Zhouguang; Gu, Yingying

2014-10-01

BiOCl micro-assembles appearing spherical and plate-like in shape consisting of ultrafine nanoplates were successfully synthesized by a simple hydrothermal method. The obtained BiOCl micro-assembles were characterized as oxygen reduction reaction (ORR) catalyst for air electrode of aluminum air batteries by using linear polarization and constant-current discharge techniques. The effect of precursor concentration on the electrochemical properties of the air electrodes based on the synthesized BiOCl micro-assembles was intensively investigated. The results demonstrated that the BiOCl catalyst exhibited promising ORR performance. Koutecky-Levich analysis indicated that a two-electron reaction was favored for the ORR mechanism of the BiOCl (0.18) sample.

Impact of KRAS codon subtypes from a randomised phase II trial of selumetinib plus docetaxel in KRAS mutant advanced non-small-cell lung cancer.

PubMed

Jänne, P A; Smith, I; McWalter, G; Mann, H; Dougherty, B; Walker, J; Orr, M C M; Hodgson, D R; Shaw, A T; Pereira, J R; Jeannin, G; Vansteenkiste, J; Barrios, C H; Franke, F A; Crinò, L; Smith, P

2015-07-14

Selumetinib (AZD6244, ARRY-142886)+docetaxel increases median overall survival (OS) and significantly improves progression-free survival (PFS) and objective response rate (ORR) compared with docetaxel alone in patients with KRAS mutant, stage IIIB/IV non-small-cell lung cancer (NSCLC; NCT00890825). Retrospective analysis of OS, PFS, ORR and change in tumour size at week 6 for different sub-populations of KRAS codon mutations. In patients receiving selumetinib+docetaxel and harbouring KRAS G12C or G12V mutations there were trends towards greater improvement in OS, PFS and ORR compared with other KRAS mutations. Different KRAS mutations in NSCLC may influence selumetinib/docetaxel sensitivity.

Linking structure to function: The search for active sites in non-platinum group metal oxygen reduction reaction catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holby, Edward F.; Zelenay, Piotr

Atomic-scale structures of oxygen reduction reaction (ORR) active sites in non-platinum group metal (non-PGM) catalysts, made from pyrolysis of carbon, nitrogen, and transition-metal (TM) precursors have been the subject of continuing discussion in the fuel cell electrocatalysis research community. We found that quantum chemical modeling is a path forward for understanding of these materials and how they catalyze the ORR. Here, we demonstrate through literature examples of how such modeling can be used to better understand non-PGM ORR active site relative stability and activity and how such efforts can also aid in the interpretation of experimental signatures produced by thesemore » materials.« less

Dissolution of Pt during Oxygen Reduction Reaction Produces Pt Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bae, Je Hyun; Brocenschi, Ricardo F.; Kisslinger, Kim

The loss of Pt during the oxygen reduction reaction (ORR) affects the performance and economic viability of fuel cells and sensors. Our group previously observed the dissolution of Pt nanoelectrodes at moderately negative potentials during the ORR. Here we report a more detailed study of this process and identify its product. The nanoporous Pt surface formed during the ORR was visualized by AFM and high-resolution SEM, which also showed ~5 nm sized Pt particles on the glass surface surrounding the electrode. Furthermore, the release of these nanoparticles into the solution was confirmed by monitoring their catalytically amplified collisions with amore » Hg-coated microelectrode used as the tip in the scanning electrochemical microscope (SECM).« less

Linking structure to function: The search for active sites in non-platinum group metal oxygen reduction reaction catalysts

DOE PAGES

Holby, Edward F.; Zelenay, Piotr

2016-05-17

Atomic-scale structures of oxygen reduction reaction (ORR) active sites in non-platinum group metal (non-PGM) catalysts, made from pyrolysis of carbon, nitrogen, and transition-metal (TM) precursors have been the subject of continuing discussion in the fuel cell electrocatalysis research community. We found that quantum chemical modeling is a path forward for understanding of these materials and how they catalyze the ORR. Here, we demonstrate through literature examples of how such modeling can be used to better understand non-PGM ORR active site relative stability and activity and how such efforts can also aid in the interpretation of experimental signatures produced by thesemore » materials.« less

Effect of ordering of PtCu₃ nanoparticle structure on the activity and stability for the oxygen reduction reaction.

PubMed

Hodnik, Nejc; Jeyabharathi, Chinnaiah; Meier, Josef C; Kostka, Alexander; Phani, Kanala L; Rečnik, Aleksander; Bele, Marjan; Hočevar, Stanko; Gaberšček, Miran; Mayrhofer, Karl J J

2014-07-21

In this study the performance enhancement effect of structural ordering for the oxygen reduction reaction (ORR) is systematically studied. Two samples of PtCu3 nanoparticles embedded on a graphitic carbon support are carefully prepared with identical initial composition, particle dispersion and size distribution, yet with different degrees of structural ordering. Thus we can eliminate all coinciding effects and unambiguously relate the improved activity of the ORR and more importantly the enhanced stability to the ordered nanostructure. Interestingly, the electrochemically induced morphological changes are common to both ordered and disordered samples. The observed effect could have a groundbreaking impact on the future directions in the rational design of active and stable platinum alloyed ORR catalysts.

Dissolution of Pt during Oxygen Reduction Reaction Produces Pt Nanoparticles

DOE PAGES

Bae, Je Hyun; Brocenschi, Ricardo F.; Kisslinger, Kim; ...

2017-11-15

The loss of Pt during the oxygen reduction reaction (ORR) affects the performance and economic viability of fuel cells and sensors. Our group previously observed the dissolution of Pt nanoelectrodes at moderately negative potentials during the ORR. Here we report a more detailed study of this process and identify its product. The nanoporous Pt surface formed during the ORR was visualized by AFM and high-resolution SEM, which also showed ~5 nm sized Pt particles on the glass surface surrounding the electrode. Furthermore, the release of these nanoparticles into the solution was confirmed by monitoring their catalytically amplified collisions with amore » Hg-coated microelectrode used as the tip in the scanning electrochemical microscope (SECM).« less

Survey of protected terrestrial vertebrates on the Oak Ridge Reservation. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, J.M.; Vail, E.R.; Webb, J.W.

1996-05-01

Surveys of protected terrestrial vertebrates on the Oak Ridge Reservation (ORR) were conducted from October 1994 through May 1996. The surveys were undertaken to help avoid or minimize the potential impacts of projects on the ORR to species listed by the state or federal government as endangered, threatened, or in need-of-management; federal species of concern were included. Results of the survey will also assist in effectively managing the ORR. Currently, there are 69 species of federal- or state-listed terrestrial vertebrates (20 reptiles and amphibians, 20 mammals, and 29 birds) that may occur in Tennessee. Listed animal species that might bemore » present on the ORR were targeted for survey using a prioritization system based on historical and recent sightings, known species distributions, presence of suitable habitat, literature reviews, and personal communications. Survey methods included trapping, seining, monitoring artificial covers, active searching, and avian surveys. Surveys were conducted during the time of year when each targeted species was most likely to be encountered. The report also includes ancillary information. Records are provided for nonlisted species (44 species of reptiles and amphibians, 155 species of birds, and 28 species of mammals). Categorization of survey sites into 1 or more of 19 habitat types, which are briefly described, is presented. Notes are summarized on the occurrence of threatened and endangered species on the ORR. The report also lists threatened and endangered species not found that might be located by additional surveys, recommends three survey areas for natural-area status due to wildlife value, and suggests several avenues for future work.« less

Cobalt-Doped Perovskite-Type Oxide LaMnO3 as Bifunctional Oxygen Catalysts for Hybrid Lithium-Oxygen Batteries.

PubMed

Liu, Xiao; Gong, Hao; Wang, Tao; Guo, Hu; Song, Li; Xia, Wei; Gao, Bin; Jiang, Zhongyi; Feng, Linfei; He, Jianping

2018-03-02

Perovskite-type oxides based on rare-earth metals containing lanthanum manganate are promising catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolyte. Perovskite-type LaMnO 3 shows excellent ORR performance, but poor OER activity. To improve the OER performance of LaMnO 3 , the element cobalt is doped into perovskite-type LaMnO 3 through a sol-gel method followed by a calcination process. To assess electrocatalytic activities for the ORR and OER, a series of LaMn 1-x Co x O 3 (x=0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5) perovskite oxides were synthesized. The results indicate that the amount of doped cobalt has a significant effect on the catalytic performance of LaMn 1-x Co x O 3 . If x=0.3, LaMn 0.7 Co 0.3 O 3 not only shows a tolerable electrocatalytic activity for the ORR, but also exhibits a great improvement (>200 mV) on the catalytic activity for the OER; this indicates that the doping of cobalt is an effective approach to improve the OER performance of LaMnO 3 . Furthermore, the results demonstrate that LaMn 0.7 Co 0.3 O 3 is a promising cost-effective bifunctional catalyst with high performance in the ORR and OER for application in hybrid Li-O 2 batteries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

77 FR 52752 - Notice of FY 2012 Refugee Social Services Formula Awards to States and Wilson/Fish Alternative...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-30

... allocations for Social Services are available on ORR's Web site at: http://www.acf.hhs.gov/programs/orr/policy...] Notice of FY 2012 Refugee Social Services Formula Awards to States and Wilson/Fish Alternative Project... allocation of Refugee Social Services formula awards to States and Wilson/Fish Alternative Project grantees...

A Chebyshev matrix method for spatial modes of the Orr-Sommerfeld equation

NASA Technical Reports Server (NTRS)

Danabasoglu, G.; Biringen, S.

1989-01-01

The Chebyshev matrix collocation method is applied to obtain the spatial modes of the Orr-Sommerfeld equation for Poiseuille flow and the Blausius boundary layer. The problem is linearized by the companion matrix technique for semi-infinite domain using a mapping transformation. The method can be easily adapted to problems with different boundary conditions requiring different transformations.

NPS-SCAT: A CubeSat Communications System Design, Test, and Integration

DTIC Science & Technology

2009-06-01

used two patch antennas for the S-Band transceiver and a quad-canted turnstile antenna for the downlink in the 70-centimeter band ( Tuli , Orr, & Zee...Service. Retrieved March 08, 2009, from Cute-1.7 + APD II Project: http://lss.mes.titech.ac.jp/ssp/cute1.7/amateur_servic e_e.html Tuli , T.S., Orr

CuCo 2O 4 ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

DOE PAGES

Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; ...

2015-02-07

A series of CuCo 2O 4 catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo 2O 4 and it was found that CuCo 2O 4 can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It wasmore » found that the sacrificial support method (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo 2O 4. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E 1/2) of CuCo 2O 4-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.« less

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.

We report that identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Furthermore, we report for the very first time, F doped Cu 1.5Mn 1.5O 4, identified by exploiting theoretical first principles calculations for ORR and OERmore » in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO 2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO 2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.« less

Metal-organic frameworks derived platinum-cobalt bimetallic nanoparticles in nitrogen-doped hollow porous carbon capsules as a highly active and durable catalyst for oxygen reduction reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ying, Jie; Li, Jing; Jiang, Gaopeng

Pt-based nanomaterials are regarded as the most efficient electrocatalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, widespread adoption of PEMFCs requires solutions to major challenges encountered with ORR catalysts, namely high cost, sluggish kinetics, and low durability. In this paper, a new efficient method utilizing Co-based metal-organic frameworks is developed to produce PtCo bimetallic nanoparticles embedded in unique nitrogen-doped hollow porous carbon capsules. The obtained catalyst demonstrates an outstanding ORR performance, with a mass activity that is 5.5 and 13.5 times greater than that of commercial Pt/C and Pt black, respectively. Most importantly,more » the product exhibits dramatically improved durability in terms of both electrochemically active surface area (ECAS) and mass activity compared to commercial Pt/C and Pt black catalysts. Finally, the remarkable ORR performance demonstrated here can be attributed to the structural features of the catalyst (its alloy structure, high dispersion and fine particle size) and the carbon support (its nitrogen dopant, large surface area and hollow porous structure).« less

In Situ Imaging the Oxygen Reduction Reactions of Solid State Na-O2 Batteries with CuO Nanowires as the Air Cathode.

PubMed

Liu, Qiunan; Yang, Tingting; Du, Congcong; Tang, Yongfu; Sun, Yong; Jia, Peng; Chen, Jingzhao; Ye, Hongjun; Shen, Tongde; Peng, Qiuming; Zhang, Liqiang; Huang, Jianyu

2018-06-13

We report real time imaging of the oxygen reduction reactions (ORRs) in all solid state sodium oxygen batteries (SOBs) with CuO nanowires (NWs) as the air cathode in an aberration-corrected environmental transmission electron microscope under an oxygen environment. The ORR occurred in a distinct two-step reaction, namely, a first conversion reaction followed by a second multiple ORR. In the former, CuO was first converted to Cu 2 O and then to Cu; in the latter, NaO 2 formed first, followed by its disproportionation to Na 2 O 2 and O 2 . Concurrent with the two distinct electrochemical reactions, the CuO NWs experienced multiple consecutive large volume expansions. It is evident that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter one-electron-transfer ORR, leading to the formation of NaO 2 . Remarkably, no carbonate formation was detected in the oxygen cathode after cycling due to the absence of carbon source in the whole battery setup. These results provide fundamental understanding into the oxygen chemistry in the carbonless air cathode in all solid state Na-O 2 batteries.

Remedial investigation/feasibility study of the Clinch River/Poplar Creek Operable Unit. Volume 3. Risk assessment information. Appendixes E, F

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-03-01

This report presents the findings of an investigation into contamination of the Clinch River and Poplar Creek near the U.S. Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) in eastern Tennessee. For more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities at the ORR. In 1989, the ORR was placed on the National Priorities List (NPL), established and maintained under the federal Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Under CERCLA, NPL sites must be investigated to determine the nature and extentmore » of contamination at the site, assess the risk to human health and the environment posed by the site, and, if necessary, identify feasible remedial alternatives that could be used to clean the site and reduce risk. To facilitate the overall environmental restoration effort at the ORR, CERCLA activities are being implemented individually as distinct operable units (OUs). This document is Volume 3 of the combined Remedial Investigation and Feasibility Study Report for the Clinch River/Poplar Creek OU.« less

Highly uniform and monodisperse carbon nanospheres enriched with cobalt-nitrogen active sites as a potential oxygen reduction electrocatalyst

NASA Astrophysics Data System (ADS)

Wan, Xing; Wang, Hongjuan; Yu, Hao; Peng, Feng

2017-04-01

Uniform cobalt and nitrogen co-doped carbon nanospheres (CoN-CNS) with high specific surface area (865 m2 g-1) have been prepared by a simple but efficient method. The prepared CoN-CNS catalyst exhibits outstanding catalytic performance for the oxygen reduction reaction (ORR) in both alkaline and acidic electrolytes. In alkaline electrolyte, the prepared CoN-CNS has more positive half-wave potential and larger kinetic current density than commercial Pt/C. In acidic electrolyte, CoN-CNS also shows good ORR activity with high electron transfer number, its onset and half-wave potentials are all close to those of commercial carbon supported platinum catalyst (Pt/C). CoN-CNS catalyst shows more superior stability and higher methanol-tolerance than commercial Pt/C both in alkaline and in acidic electrolytes. The potassium thiocyanate-poisoning test further confirms that the cobalt-nitrogen active sites exist in CoN-CNS, which are dominating to endow high ORR catalytic activity in acidic electrolyte. This study develops a new method to prepare non-precious metal catalyst with excellent ORR performances for direct methanol fuel cells.

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

DOE PAGES

Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; ...

2016-07-06

We report that identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Furthermore, we report for the very first time, F doped Cu 1.5Mn 1.5O 4, identified by exploiting theoretical first principles calculations for ORR and OERmore » in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO 2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO 2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.« less

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

PubMed Central

Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; Kuruba, Ramalinga; Damodaran, Krishnan; Jampani, Prashanth; Gattu, Bharat; Shanthi, Pavithra Murugavel; Damle, Sameer S.; Kumta, Prashant N.

2016-01-01

Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations. PMID:27380719

Structural Dynamics and Activity of Nanocatalysts Inside Fuel Cells by in-operando Atomic Pair Distribution Studies

NASA Astrophysics Data System (ADS)

Prasai, Binay

We present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). Using in-operando high-energy X-ray diffraction we tracked the evolution of the atomic structure and activity of noble metal-transition metal(NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Data were analyzed in terms of atomic pair distribution functions and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore, we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation.

Remedial investigation/feasibility study of the Clinch River/Poplar Creek operable unit. Volume 3: Appendixes E and F -- Risk assessment information

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-06-01

This report presents the findings of an investigation into contamination of the Clinch River and Poplar Creek near the US Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) in eastern Tennessee. For more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities at the ORR. In 1989, the ORR was placed on the National Priorities List (NPL), established and maintained under the federal Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Under CERCLA, NPL sites must be investigated to determine the nature and extentmore » of contamination at the site, assess the risk to human health and the environment posed by the site, and, if necessary, identify feasible remedial alternatives that could be used to clean the site and reduce risk. To facilitate the overall environmental restoration effort at the ORR, CERCLA activities are being implemented individually as distinct operable units (OUs). This document is the combined Remedial Investigation and Feasibility Study Report for the Clinch River/Poplar Creek OU.« less

N-doped graphene coupled with Co nanoparticles as an efficient electrocatalyst for oxygen reduction in alkaline media

NASA Astrophysics Data System (ADS)

Zhang, Geng; Lu, Wangting; Cao, Feifei; Xiao, Zhidong; Zheng, Xinsheng

2016-01-01

Development of low-cost and highly efficient electrocatalysts for oxygen reduction reaction (ORR) is still a great challenge for the large-scale application of fuel cells and metal-air batteries. Herein, a noble metal-free ORR electrocatalyst in the form of N-doped graphene coupled with part of Co nanoparticles encased in N-doped graphitic shells (named as SUCo-0.03-800) is prepared by facile one-step pyrolysis of the mixture of sucrose, urea and cobalt nitrate. The novel structure is confirmed by High Resolution-TEM, XRD, XPS and Raman spectroscopy. SUCo-0.03-800 presents comparable ORR catalytic activity to commercial Pt/C catalyst with a dominating four-electron pathway under alkaline conditions, and both of its mass activity and volume activity also outperform Co-free N-doped graphene and other Co/N-C hybrids with higher Co content, which may probably be ascribed to the high specific surface area, novel structure and synergistic effect between encased Co nanoparticles and N-doped graphitic shell. Additionally, SUCo-0.03-800 also shows outstanding stability and improved selectivity towards ORR, making it a promising alternative to Pt with potential application in fuel cells and metal-air batteries.

Remedial investigation/feasibility study of the Clinch River/Poplar Creek Operable Unit. Volume 2. Biota and representative concentrations of contaminants. Appendixes A, B, C, D

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-03-01

This report presents the findings of an investigation into contamination of the Clinch River and Poplar Creek near the U.S. Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) in eastern Tennessee. For more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities at the ORR. In 1989, the ORR was placed on the National Priorities List (NPL), established and maintained under the federal Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Under CERCLA, NPL sites must be investigated to determine the nature and extentmore » of contamination at the site, assess the risk to human health and the environment posed by the site, and, if necessary, identify feasible remedial alternatives that could be used to clean the site and reduce risk. To facilitate the overall environmental restoration effort at the ORR, CERCLA activities are being implemented individually as distinct operable units (OU`s). This document is the combined Remedial Investigation and Feasibility Study Report for the Clinch River/Poplar Creek OU.« less

Remedial investigation/feasibility study of the Clinch River/Poplar Creek Operable Unit. Volume 2. Appendixes A, B, C, and D-Biota and representative concentrations of contaminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-06-01

This report presents the findings of an investigation into contamination of the Clinch River and Poplar Creek near the U.S. Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) in eastern Tennessee. For more than 50 years, various hazardous and radioactive substances have been released to the environment as a result of operations and waste management activities at the ORR. In 1989, the ORR was placed on the National Priorities List (NPL), established and maintained under the federal Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Under CERCLA, NPL sites must be investigated to determine the nature and extentmore » of contamination at the site, assess the risk to human health and the environment posed by the site, and, if necessary, identify feasible remedial alternatives that could be used to clean the site and reduce risk. To facilitate the overall environmental restoration effort at the ORR, CERCLA activities are being implemented individually as distinct operable units (OUs). This document is Volume 2 of the combined Remedial Investigation and Feasibility Study Report for the Clinch River/Poplar Creek OU.« less

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

NASA Astrophysics Data System (ADS)

Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; Kuruba, Ramalinga; Damodaran, Krishnan; Jampani, Prashanth; Gattu, Bharat; Shanthi, Pavithra Murugavel; Damle, Sameer S.; Kumta, Prashant N.

2016-07-01

Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.

N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells

PubMed Central

Shui, Jianglan; Wang, Min; Du, Feng; Dai, Liming

2015-01-01

The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells. PMID:26601132

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts.

PubMed

Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I; Kuruba, Ramalinga; Damodaran, Krishnan; Jampani, Prashanth; Gattu, Bharat; Shanthi, Pavithra Murugavel; Damle, Sameer S; Kumta, Prashant N

2016-07-06

Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.

N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells.

PubMed

Shui, Jianglan; Wang, Min; Du, Feng; Dai, Liming

2015-02-01

The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells.

Metal-organic frameworks derived platinum-cobalt bimetallic nanoparticles in nitrogen-doped hollow porous carbon capsules as a highly active and durable catalyst for oxygen reduction reaction

DOE PAGES

Ying, Jie; Li, Jing; Jiang, Gaopeng; ...

2017-11-29

Pt-based nanomaterials are regarded as the most efficient electrocatalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, widespread adoption of PEMFCs requires solutions to major challenges encountered with ORR catalysts, namely high cost, sluggish kinetics, and low durability. In this paper, a new efficient method utilizing Co-based metal-organic frameworks is developed to produce PtCo bimetallic nanoparticles embedded in unique nitrogen-doped hollow porous carbon capsules. The obtained catalyst demonstrates an outstanding ORR performance, with a mass activity that is 5.5 and 13.5 times greater than that of commercial Pt/C and Pt black, respectively. Most importantly,more » the product exhibits dramatically improved durability in terms of both electrochemically active surface area (ECAS) and mass activity compared to commercial Pt/C and Pt black catalysts. Finally, the remarkable ORR performance demonstrated here can be attributed to the structural features of the catalyst (its alloy structure, high dispersion and fine particle size) and the carbon support (its nitrogen dopant, large surface area and hollow porous structure).« less

Impact of KRAS codon subtypes from a randomised phase II trial of selumetinib plus docetaxel in KRAS mutant advanced non-small-cell lung cancer

PubMed Central

Jänne, P A; Smith, I; McWalter, G; Mann, H; Dougherty, B; Walker, J; Orr, M C M; Hodgson, D R; Shaw, A T; Pereira, J R; Jeannin, G; Vansteenkiste, J; Barrios, C H; Franke, F A; Crinò, L; Smith, P

2015-01-01

Background: Selumetinib (AZD6244, ARRY-142886)+docetaxel increases median overall survival (OS) and significantly improves progression-free survival (PFS) and objective response rate (ORR) compared with docetaxel alone in patients with KRAS mutant, stage IIIB/IV non-small-cell lung cancer (NSCLC; NCT00890825). Methods: Retrospective analysis of OS, PFS, ORR and change in tumour size at week 6 for different sub-populations of KRAS codon mutations. Results: In patients receiving selumetinib+docetaxel and harbouring KRAS G12C or G12V mutations there were trends towards greater improvement in OS, PFS and ORR compared with other KRAS mutations. Conclusion: Different KRAS mutations in NSCLC may influence selumetinib/docetaxel sensitivity. PMID:26125448

Oxygen Reduction Reaction on PtCo Nanocatalyst: (Bi)sulfate Anion Poisoning

NASA Astrophysics Data System (ADS)

Liu, Jie; Huang, Yan

2018-05-01

Pt alloy electrocatalysts are susceptible to anion adsorption in the working environment of fuel cells. In this work, the unavoidable bisulfate and sulfate ((bi)sulfate) poisoning of the oxygen reduction reaction (ORR) on a common PtCo nanocatalyst was studied by the rotating disk electrode (RDE) technique, for the first time to the best of our knowledge. The specific activity decreases linearly with the logarithm of (bi)sulfate concentration under various high potentials. This demonstrates that the (bi)sulfate adsorption does not affect the free energy of ORR activation at a given potential. Moreover, it is speculated that these two conditions, the adsorption of one O2 molecule onto two Pt sites and this adsorption as a rate-determining step of ORR reaction, are unlikely to exist simultaneously.

Suppression of oxygen reduction reaction activity on Pt-based electrocatalysts from ionomer incorporation

NASA Astrophysics Data System (ADS)

Shinozaki, Kazuma; Morimoto, Yu; Pivovar, Bryan S.; Kocha, Shyam S.

2016-09-01

The impact of Nafion on the oxygen reduction reaction (ORR) activity is studied for Pt/C and Pt-alloy/C catalysts using thin-film rotating disk electrode (TF-RDE) methods in 0.1 M HClO4. Ultrathin uniform catalyst layers and standardized activity measurement protocols are employed to obtain accurate and reproducible ORR activity. Nafion lowers the ORR activity which plateaus with increasing loading on Pt catalysts. Pt particle size is found not to have significant influence on the extent of the SA decrease upon Nafion incorporation. Catalysts using high surface area carbon (HSC) support exhibit attenuated activity loss resulting from lower ionomer coverage on catalyst particles located within the deep pores. The impact of metallic composition on the activity loss due to Nafion incorporation is also discussed.

Apatorsen plus docetaxel versus docetaxel alone in platinum-resistant metastatic urothelial carcinoma (Borealis-2).

PubMed

Rosenberg, Jonathan E; Hahn, Noah M; Regan, Meredith M; Werner, Lillian; Alva, Ajjai; George, Saby; Picus, Joel; Alter, Robert; Balar, Arjun; Hoffman-Censits, Jean; Grivas, Petros; Lauer, Richard; Guancial, Elizabeth A; Hoimes, Christopher; Sonpavde, Guru; Albany, Constantine; Stein, Mark N; Breen, Tim; Jacobs, Cindy; Anderson, Kirsten; Bellmunt, Joaquim; Lalani, Aly-Khan A; Pal, Sumanta; Choueiri, Toni K

2018-05-16

A randomised study to assess the addition of apatorsen, an antisense oligonucleotide that inhibits Hsp27 expression, to docetaxel in patients with metastatic urothelial carcinoma (mUC) relapsed after prior platinum-based chemotherapy. Multicentre, phase II study with 1:1 randomisation to apatorsen (three loading doses at 600 mg intravenous followed by weekly doses) plus docetaxel (75 mg/m 2 intravenous every 21 days) (A/D) or docetaxel alone. Overall survival (OS) was the primary end point with a P value <0.1 (one-sided) being positive. Progression-free survival (PFS), objective response rate (ORR), safety, and effect of Hsp27 levels on outcomes were secondary end points. Patients randomised to A/D (n = 99) had improved OS compared to docetaxel alone (n = 101): HR: 0.80, 80% CI: 0.65-0.98, P = 0.0784, median 6.4 vs 5.9 months. PFS and ORR were similar in both arms. A/D had more incidence of sepsis and urinary tract infections. Patients with baseline Hsp27 levels <5.7 ng/mL had improved OS compared to those with levels ≥5.7 ng/mL. Patients with a decline or ≤20.5% increase in Hsp27 from baseline benefited more from A/D than those with >20.5% increase. A/D met its predefined OS end point in patients with platinum-refractory mUC in this phase II trial. This trial is hypothesis generating requiring further study before informing practice.

Cathodic current enhancement via manganese and oxygen related reactions in marine biofilms

NASA Astrophysics Data System (ADS)

Strom, Matthew James

Corrosion is a threat that has economic, and environmental impacts worldwide. Many types of corrosive attack are the subject of ongoing research. One of these areas of research is microbiologically influenced corrosion, which is the enhancement and/or initiation of corrosion events caused by microorganisms. It is well known that colonies of microorganisms can enhance cathodic currents through biofilm formation. The aim of the present work was to elucidate the role of manganese in enhancing cathodic currents in the presence of biofilms. Repeated polarizations conducted in Delaware Bay waters, on biofilm coated Cr identified potentially sustainable reduction reactions. The reduction of MnO2 and the enhancement of the oxygen reduction reaction (ORR) were proven to be factors that influence cathodic current enhancement. The removal of ambient oxygen during polarizations resulted in a shutdown of cathodic current enhancement. These field data led to an exploration of the synergistic relationship between MnO2 and the ORR. Laboratory studies of the catalysis of peroxide disproportionation by MnO2 were monitored using a hanging mercury drop electrode. Experiments were run at an ambient sweater pH of 8 and pH 9, which simulated the near-surface conditions typical of cathodes immersed in seawater. Rapid reoxidation at the more basic pH was shown to allow manganese to behave as a persistent catalyst under the typical electrochemical surface conditions of a cathode. As a result a mechanism for ORR enhancement by manganese was proposed as a unique mechanism for cathodic current enhancement in biofilms. A separate field study of Delaware biofilms on stainless steel coupled to a sacrificial Al anode was carried out to identify the ORR enhancement mechanism and sustainable redox reactions at the cathode. Chemical treatments of glutaraldehyde and formaldoxime were applied to cathodes with biofilms to distinguish between enzymatic and MnO2 related ORR enhancement. The results ruled out the enzymatic catalysis of ORR and supported the catalysis by MnO2. Sustainable redox reactions at the cathode were evaluated by monitoring the cathodic current of biofilm coated stainless steel for a year under different polarization intensities. The results showed that sustainable cathodic reactions were present in marine biofilms but their influence on the cathodic current was negligible until a potential was reached where the ORR could take place. Additionally seasonal variability was observed in the enhanced cathodic current in Delaware Bay biofilms. This was attributed to the seasonal variability of manganese in the water column.

Cumulative effect of transition metals on nitrogen and fluorine co-doped graphite nanofibers: an efficient and highly durable non-precious metal catalyst for the oxygen reduction reaction.

PubMed

Peera, S Gouse; Arunchander, A; Sahu, A K

2016-08-14

Nitrogen and fluorine co-doped graphite nanofibers (N/F-GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe-Co/NF-GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe-Co/NF-GNF catalyst compared to the simple N/F-GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe-Co/NF-GNF catalyst also exhibits complete tolerance to CH3OH and CO. The Fe-Co/NF-GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ∼110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe-Co/NF-GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe-Co/NF-GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe-Co/NF-GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M-N-C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity and long term durability of the Fe-Co/NF-GNF catalyst make it a promising ORR electrocatalyst for the fuel cell cathode reaction.

Flexible nitrogen-doped graphene/carbon nanotube/Co3O4 paper and its oxygen reduction activity

NASA Astrophysics Data System (ADS)

Li, Shan-Shan; Cong, Huai-Ping; Wang, Ping; Yu, Shu-Hong

2014-06-01

Due to the demand of an efficient, inexpensive and scalable synthesis of oxygen reduction reaction (ORR) catalyst for practical application in fuel cell, we demonstrate a facile strategy to fabricate the flexible nitrogen-doped graphene/carbon nanotube/Co3O4 (NG/CNT/Co3O4) paper catalyst. In the hydrothermal process, the in situ formation of Co3O4 nanoparticles, reduction of GO and doping of nitrogen species occur simultaneously in the assembled paper in ammonia solution. Because of the synergistic effects of three active components and the spacing effect of CNTs and Co3O4 nanoparticles on avoiding the re-aggregation of assembled graphene nanosheets, the free-standing NG/CNT/Co3O4 paper exhibits an enhanced ORR catalytic performance with stable durability and strong methanol-tolerant capability, indicating promising potential as ORR electrocatalyst in practical applications.Due to the demand of an efficient, inexpensive and scalable synthesis of oxygen reduction reaction (ORR) catalyst for practical application in fuel cell, we demonstrate a facile strategy to fabricate the flexible nitrogen-doped graphene/carbon nanotube/Co3O4 (NG/CNT/Co3O4) paper catalyst. In the hydrothermal process, the in situ formation of Co3O4 nanoparticles, reduction of GO and doping of nitrogen species occur simultaneously in the assembled paper in ammonia solution. Because of the synergistic effects of three active components and the spacing effect of CNTs and Co3O4 nanoparticles on avoiding the re-aggregation of assembled graphene nanosheets, the free-standing NG/CNT/Co3O4 paper exhibits an enhanced ORR catalytic performance with stable durability and strong methanol-tolerant capability, indicating promising potential as ORR electrocatalyst in practical applications. Electronic supplementary information (ESI) available: XRD patterns, elemental mapping images, DSC-TGA curves and XPS spectrum of NG/CNT/Co3O4 paper; SEM images and XPS spectra of NG/Co3O4 paper; RDE curves and corresponding K-L plots of different catalysts. See DOI: 10.1039/c4nr02101k

Maps of the Martian Landing Sites and Rover Traverses: Viking 1 and 2, Mars Pathfinder, and Phoenix Landers, and the Mars Exploration Rovers.

NASA Astrophysics Data System (ADS)

Parker, T. J.; Calef, F. J., III; Deen, R. G.; Gengl, H.

2016-12-01

The traverse maps produced tactically for the MER and MSL rover missions are the first step in placing the observations made by each vehicle into a local and regional geologic context. For the MER, Phoenix and MSL missions, 25cm/pixel HiRISE data is available for accurately localizing the vehicles. Viking and Mars Pathfinder, however, relied on Viking Orbiter images of several tens of m/pixel to triangulate to horizon features visible both from the ground and from orbit. After Pathfinder, MGS MOC images became available for these landing sites, enabling much better correlations to horizon features and localization predictions to be made, that were then corroborated with HiRISE images beginning 9 years ago. By combining topography data from MGS, Mars Express, and stereo processing of MRO CTX and HiRISE images into orthomosaics (ORRs) and digital elevation models (DEMs), it is possible to localize all the landers and rover positions to an accuracy of a few tens of meters with respect to the Mars global control net, and to better than half a meter with respect to other features within a HiRISE orthomosaic. JPL's MIPL produces point clouds of the MER Navcam stereo images that can be processed into 1cm/pixel ORR/DEMs that are then georeferenced to a HiRISE/CTX base map and DEM. This allows compilation of seamless mosaics of the lander and rover camera-based ORR/DEMs with the HiRISE ORR/DEM that can be viewed in 3 dimensions with GIS programs with that capability. We are re-processing the Viking Lander, Mars Pathfinder, and Phoenix lander data to allow similar ORR/DEM products to be made for those missions. For the fixed landers and Spirit, we will compile merged surface/CTX/HiRISE ORR/DEMs, that will enable accurate local and regional mapping of these landing sites, and allow comparisons of the results from these missions to be made with current and future surface missions.

2D molybdenum disulphide (2D-MoS2) modified electrodes explored towards the oxygen reduction reaction.

PubMed

Rowley-Neale, Samuel J; Fearn, Jamie M; Brownson, Dale A C; Smith, Graham C; Ji, Xiaobo; Banks, Craig E

2016-08-21

Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm(-2) modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.

Side-scan sonar imaging of the Colorado River, Grand Canyon

USGS Publications Warehouse

Anima, Roberto; Wong, Florence L.; Hogg, David; Galanis, Peter

2007-01-01

This paper presents data collection methods and side-scan sonar data collected along the Colorado River in Grand Canyon in August and September of 2000. The purpose of the data collection effort was to image the distribution of sand between Glen Canyon Dam and river mile 87.4 before and after the 31,600 cfs flow of September 6-8. The side-scan sonar imaging focused on pools between rapids but included smaller rapids where possible.

Beyond the "Rural Myth": The Business Side of Western Canadian History.

ERIC Educational Resources Information Center

Levine, Allan G.

1986-01-01

Argues that the conflict between elevator and railway operators and the grain farmers of western Canada was not so one-sided as typically presented in high school textbooks. Concludes that the 'courts' of Canadian history have promoted a 'rural myth' of the grain growers associations, the cooperative spirit of the 'Wheat Pools,' and the political…

Stabilization of Pt monolayer catalysts under harsh conditions of fuel cells

DOE PAGES

Zhang, Xiaoming; Liu, Ping; Yu, Shansheng; ...

2015-05-21

We employed density functional theory (DFT) to explore the stability of core (M = Cu, Ru, Rh, Pd, Ag, Os, Ir, Au)-shell (Pt) catalysts under harsh conditions, including solutions and reaction intermediates involved in the oxygen reduction reaction (ORR) in fuel cells. A pseudomorphic surface alloy (PSA) with a Pt monolayer (Pt 1ML) supported on an M surface, Pt 1ML/M(111) or (001), was considered as a model system. Different sets of candidate M cores were identified to achieve a stable Pt 1ML shell depending on the conditions. In vacuum conditions, the Pt 1ML shell can be stabilized on the mostmore » of M cores except Cu, Ag, and Au. The situation varies under various electrochemical conditions. Depending on the solutions and the operating reaction pathways of the ORR, different M should be considered. Pd and Ir are the only core metals studied, being able to keep the Pt ML shell intact in perchloric acid, sulfuric acid, phosphoric acid, and alkaline solutions as well as under the ORR conditions via different pathways. Ru and Os cores should also be paid attention, which only fall during the ORR via the *OOH intermediate. Rh core works well as long as the ORR does not undergo the pathway via *O intermediate. Our results show that PSAs can behave differently from the near surface alloy, Pt 1ML/M 1ML/Pt(111), highlighting the importance of considering both chemical environments and the atomic structures in rational design of highly stable core-shell nanocatalysts. Finally, the roles that d-band center of a core M played in determining the stability of supported Pt 1ML shell were also discussed.« less

Fe Stabilization by Intermetallic L1 0-FePt and Pt Catalysis Enhancement in L1 0-FePt/Pt Nanoparticles for Efficient Oxygen Reduction Reaction in Fuel Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Junrui; Xi, Zheng; Pan, Yung -Tin

We report in this article a detailed study on how to stabilize a first-row transition metal (M) in an intermetallic L1 0-MPt alloy nanoparticle (NP) structure and how to surround the L1 0-MPt with an atomic layer of Pt to enhance the electrocatalysis of Pt for oxygen reduction reaction (ORR) in fuel cell operation conditions. Using 8 nm FePt NPs as an example, we demonstrate that Fe can be stabilized more efficiently in a core/shell structured L1 0-FePt/Pt with a 5 Å Pt shell. The presence of Fe in the alloy core induces the desired compression of the thin Ptmore » shell, especially the 2 atomic layers of Pt shell, further improving the ORR catalysis. This leads to much enhanced Pt catalysis for ORR in 0.1 M HClO 4 solution (both at room temperature and 60°C) and in the membrane electrode assembly (MEA) at 80°C. The L1 0-FePt/Pt catalyst has a mass activity of 0.7 A/mg Pt from the half-cell ORR test and shows no obvious mass activity loss after 30,000 potential cycles between 0.6 V and 0.95 V at 80°C in the MEA, meeting the DOE 2020 target (<40% loss in mass activity). Here, we are extending the concept and preparing other L1 0-MPt/Pt NPs, such as L1 0-CoPt/Pt NPs, with reduced NP size as a highly efficient ORR catalyst for automotive fuel cell applications.« less

Comparison of the effectiveness of whole-brain radiotherapy plus temozolomide versus whole-brain radiotherapy in treating brain metastases based on a systematic review of randomized controlled trials.

PubMed

Bai, Gui-Rong; An, Jin-Bing; Chu, Yang; Wang, Xiang-Yang; Li, Shu-Ming; Yan, Kai-Jing; Lü, Fu-Rong; Gu, Ning; Griffin, Amanda N; Sun, Bin-Yuan; Li, Wei; Wang, Guo-Cheng; Zhou, Shui-Ping; Sun, He; Liu, Chang-Xiao

2016-01-01

Temozolomide (TMZ) combination with whole-brain radiotherapy (WBRT) has been tested by many randomized controlled trials in the treatment of brain metastases (BMs) in China and other countries. We performed an up-to-date meta-analysis to determine (i) the log odds ratios (LORs) of objective response (ORR) and adverse effects (AEs) for all-grade, and (ii) the T value of mean overall survival in patients with BMs treated with WBRT combined with TMZ versus WBRT alone. PubMed, Chinese National Knowledge Infrastructure, and WanFang Data were searched for articles published up to 28 January 2015. Eligible studies were selected according to the PRISMA statement. ORR, AEs, and 95% confidence intervals were calculated using random-effects models. Eighteen studies were included in our analysis. A total of 1028 participants were enrolled. Summary LORs of ORR were 1.0239 (P<0.0001) on comparing WBRT plus TMZ with WBRT ORR (n=17). The overall mean difference of mean overall survival (n=17) between TMZ plus WBRT and WBRT was 2.2505 weeks (P=0.02185). There was a significant difference between WBRT plus TMZ and WBRT alone with a LOR of AEs for all-grade of (i) 0.923 for gastrointestinal toxicity and (ii) 0.7978 for myelosuppression. Sensitivity analysis and subgroup analysis were also performed. The 18 eligible randomized controlled trials demonstrated that the combination of WBRT and TMZ significantly improves the ORR and is statistically insignificant in prolonging the survival of patients with BMs. In addition, an increase in the incidence of gastrointestinal toxicity and myelosuppression was significant for all-grade.

Homogeneous deposition-assisted synthesis of iron-nitrogen composites on graphene as highly efficient non-precious metal electrocatalysts for microbial fuel cell power generation

NASA Astrophysics Data System (ADS)

Liu, Yuan; Jin, Xiao-Jun; Dionysiou, Dionysios D.; Liu, Hong; Huang, Yu-Ming

2015-03-01

This work proposed a novel strategy for synthesizing highly efficient non-precious metal oxygen reduction reaction (ORR) electrocatalysts. Fe complexes were homogeneously deposited (HD) on graphene oxide through in situ hydrolysis of urea, followed by two-step pyrolysis under Ar and NH3 atmospheres, resulting in formation of Fe- and N-functionalized graphene (HD-FeN/G). The morphology, crystalline structure and elemental composition of HD-FeN/G were characterized. ORR activity was evaluated by using a rotary disk electrode (RDE) electrochemical system. HD improved the loading and distribution of the Fe-Nx composites on graphene. The ORR activity of the as-prepared HD-FeN/G in neutral medium was comparable to that of the state-of-the-art commercial Pt/C and significantly superior to a FeN/G counterpart produced via traditional approach. The ORR electron transfer number of HD-FeN/G was as high as 3.83 ± 0.08, which suggested that ORR catalysis proceeds through a four-electron pathway. HD-FeN/G was used as a cathodic electrocatalyst in microbial fuel cells (MFCs), and the resultant HD-FeN/G-MFC showed comparable voltage output and maximum power density to those of Pt/C-MFC. The HD-FeN/G-MFC achieved a maximum power density of 885 mW m-2, which was much higher than that of FeN/G-MFC (708 mW m-2). These findings demonstrate that HD-FeN/G produced through the novel synthesis strategy proposed in this work would be a good candidate as cathodic electrocatalyst in MFCs.

Nanoparticles of Ag with a Pt and Pd rich surface supported on carbon as a new catalyst for the oxygen electroreduction reaction (ORR) in acid electrolytes: Part 1

NASA Astrophysics Data System (ADS)

Pech-Pech, I. E.; Gervasio, Dominic F.; Godínez-Garcia, A.; Solorza-Feria, O.; Pérez-Robles, J. F.

2015-02-01

Silver (Ag) nanoparticles enriched with platinum (Pt) and palladium (Pd) on their surfaces (Ag@Pt0.1Pd0.1) are supported on Vulcan XC-72 carbon (C) to form a new catalyst (Ag@Pt0.1Pd0.1/C) for the oxygen reduction reaction (ORR) in acid electrolytes. This catalyst is prepared in one pot by reducing Ag and then Pt and Pd metal salts with sodium borohydride in the presence of trisodium citrate then adding XC-72 while applying intense ultrasound. The metallic Ag@Pt0.1Pd0.1 nanoparticles contain 2 weight percent of Pt, are spherical and have an average size less than 10 nm as determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). At the ORR potentials, Ag nanoparticles on carbon (Ag/C) rapidly lose Ag by dissolution and show no more catalytic activity for the ORR than the carbon support, whereas Ag@Pt0.1Pd0.1/C is a stable catalyst and exhibits 1.4 and 1.6 fold greater specific activity, also 3.6 and 2.8 fold greater mass activity for ORR in 0.5 M H2SO4 solution than comparable Pt/C and Pt0.5Pd0.5/C catalysts with the same Pt loading as determined for thin-films of these catalysts on a rotating-disk electrode (TF-RDE). Using silver nanoparticles increases Pt utilization and therefore decreases Pt-loading and cost of a catalyst for a proton exchange membrane fuel cell (PEMFC) electrode.

Fe Stabilization by Intermetallic L1 0-FePt and Pt Catalysis Enhancement in L1 0-FePt/Pt Nanoparticles for Efficient Oxygen Reduction Reaction in Fuel Cells

DOE PAGES

Li, Junrui; Xi, Zheng; Pan, Yung -Tin; ...

2018-02-07

We report in this article a detailed study on how to stabilize a first-row transition metal (M) in an intermetallic L1 0-MPt alloy nanoparticle (NP) structure and how to surround the L1 0-MPt with an atomic layer of Pt to enhance the electrocatalysis of Pt for oxygen reduction reaction (ORR) in fuel cell operation conditions. Using 8 nm FePt NPs as an example, we demonstrate that Fe can be stabilized more efficiently in a core/shell structured L1 0-FePt/Pt with a 5 Å Pt shell. The presence of Fe in the alloy core induces the desired compression of the thin Ptmore » shell, especially the 2 atomic layers of Pt shell, further improving the ORR catalysis. This leads to much enhanced Pt catalysis for ORR in 0.1 M HClO 4 solution (both at room temperature and 60°C) and in the membrane electrode assembly (MEA) at 80°C. The L1 0-FePt/Pt catalyst has a mass activity of 0.7 A/mg Pt from the half-cell ORR test and shows no obvious mass activity loss after 30,000 potential cycles between 0.6 V and 0.95 V at 80°C in the MEA, meeting the DOE 2020 target (<40% loss in mass activity). Here, we are extending the concept and preparing other L1 0-MPt/Pt NPs, such as L1 0-CoPt/Pt NPs, with reduced NP size as a highly efficient ORR catalyst for automotive fuel cell applications.« less

Oxygen reduction reaction (orr) on bimetallic AuPt and AuPd(1 0 0)-electrodes: Effects of the heteroatomic junction on the reaction paths

NASA Astrophysics Data System (ADS)

Schulte, E.; Belletti, G.; Arce, M.; Quaino, P.

2018-05-01

The seek for materials to enhance the oxygen reduction reaction (orr) rate is a highly relevant topic due to its implication in fuel cell devices. Herein, the orr on bimetallic electrocatalysts based on Au-M (M = Pt, Pd) has been studied computationally, by performing density functional theory calculations. Bimetallic (1 0 0) electrode surfaces with two different Au:M ratios were proposed, and two possible pathways, associative and dissociative, were considered for the orr. Changes in the electronic properties of these materials with respect to the pure metals were acknowledged to gain understanding in the overall reactivity trend. The effect of the bimetallic junction on the stability of the intermediates O2 and OOH was also evaluated by means of geometrical and energetic parameters; being the intermediates preferably adsorbed on Pt/Pd atoms, but presenting in some cases higher adsorption energies compared with bare metals. Finally, the kinetics of the Osbnd O bond breaking in O2∗ and OOH∗ adsorbed intermediates in the bimetallic materials and the influence of the Au-M junction were studied by means of the nudge elastic-band method. A barrierless process for the scission of O2∗ was found in Au-M for the higher M ratios. Surprisingly, for Au-M with lower M ratios, the barriers were much lower than for pure Au surfaces, suggesting a highly reactive surface towards the orr. The Osbnd O scission of the OOH∗ was found to be a barrierless process in Ausbnd Pt systems and nearly barrierless in all Ausbnd Pd systems, implying that the reduction ofO2 in these systems proceeds via the full reduction of O2 to H2O , avoiding H2O2 formation.

Stabilization of Pt monolayer catalysts under harsh conditions of fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xiaoming; Yu, Shansheng; Zheng, Weitao, E-mail: wtzheng@jlu.edu.cn, E-mail: pingliu3@bnl.gov

2015-05-21

We employed density functional theory to explore the stability of core (M = Cu, Ru, Rh, Pd, Ag, Os, Ir, Au)-shell (Pt) catalysts under harsh conditions, including solutions and reaction intermediates involved in the oxygen reduction reaction (ORR) in fuel cells. A pseudomorphic surface alloy (PSA) with a Pt monolayer (Pt{sub 1ML}) supported on an M surface, Pt{sub 1ML}/M(111) or (001), was considered as a model system. Different sets of candidate M cores were identified to achieve a stable Pt{sub 1ML} shell depending on the conditions. In vacuum conditions, the Pt{sub 1ML} shell can be stabilized on the most ofmore » M cores except Cu, Ag, and Au. The situation varies under various electrochemical conditions. Depending on the solutions and the operating reaction pathways of the ORR, different M should be considered. Pd and Ir are the only core metals studied, being able to keep the Pt{sub ML} shell intact in perchloric acid, sulfuric acid, phosphoric acid, and alkaline solutions as well as under the ORR conditions via different pathways. Ru and Os cores should also be paid attention, which only fall during the ORR via the *OOH intermediate. Rh core works well as long as the ORR does not undergo the pathway via *O intermediate. Our results show that PSAs can behave differently from the near surface alloy, Pt{sub 1ML}/M{sub 1ML}/Pt(111), highlighting the importance of considering both chemical environments and the atomic structures in rational design of highly stable core-shell nanocatalysts. Finally, the roles that d-band center of a core M played in determining the stability of supported Pt{sub 1ML} shell were also discussed.« less

Controlling the Interfacial Environment in the Electrosynthesis of MnOx Nanostructures for High-Performance Oxygen Reduction/Evolution Electrocatalysis.

PubMed

Hosseini-Benhangi, Pooya; Kung, Chun Haow; Alfantazi, Akram; Gyenge, Elöd L

2017-08-16

High-performance, nonprecious metal bifunctional electrocatalysts for the oxygen reduction and evolution reactions (ORR and OER, respectively) are of great importance for rechargeable metal-air batteries and regenerative fuel cells. A comprehensive study based on statistical design of experiments is presented to investigate and optimize the surfactant-assisted structure and the resultant bifunctional ORR/OER activity of anodically deposited manganese oxide (MnO x ) catalysts. Three classes of surfactants are studied: anionic (sodium dodecyl sulfate, SDS), non-ionic (t-octylphenoxypolyethoxyethanol, Triton X-100), and cationic (cetyltrimethylammonium bromide, CTAB). The adsorption of surfactants has two main effects: increased deposition current density due to higher Mn 2+ and Mn 3+ concentrations at the outer Helmholtz plane (Frumkin effect on the electrodeposition kinetics) and templating of the MnO x nanostructure. CTAB produces MnO x with nanoneedle (1D) morphology, whereas nanospherical- and nanopetal-like morphologies are obtained with SDS and Triton, respectively. The bifunctional performance is assessed based on three criteria: OER/ORR onset potential window (defined at 2 and -2 mA cm -2 ) and separately the ORR and OER mass activities. The best compromise among these three criteria is obtained either with Triton X-100 deposited catalyst composed of MnOOH and Mn 3 O 4 or SDS deposited catalyst containing a combination of α- and β-MnO 2 , MnOOH, and Mn 3 O 4 .The interaction effects among the deposition variables (surfactant type and concentration, anode potential, Mn 2+ concentration, and temperature) reveal the optimal strategy for high-activity bifunctional MnO x catalyst synthesis. Mass activities for OER and ORR up to 49 A g -1 (at 1556 mV RHE ) and -1.36 A g -1 (at 656 mV RHE ) are obtained, respectively.

[Investigation of the medical and social situation of patients managed by opiate replacement regimens for over 10 years by their GP].

PubMed

Messaadi, Nassir; Favre, Jonathan; Rolland, Benjamin; Cottencin, Olivier; Calafiore, Matthieu; Stalnikiewicz, Bertrand; Berkhout, Christophe

2016-10-01

Management with opiate replacement regimens (ORRs) of patients presenting to primary care settings with opiate addiction has become a long-term follow-up. The aim of this survey study was to describe patients who had been prescribed ORRs for at least 10 years by their general practitioner (GP). In 2011, two questionnaires were sent to a sample of 38 GPs prescribing ORRs in Northern France. Doctors' questionnaires collected their typology and opinions on their patients receiving opiate substitution treatments for over 10 years. Patients' questionnaires were completed in the presence of the patient. Twenty-three doctors' and 83 patients' questionnaires were suitable for analysis. The average number of listed ORR patients was 14.2 and 3.6 had been managed for 10 years or more. Misuse persisted: 30.5% of GPs considered that it was carried out by at least by 15% of patients. Average dosages were 60.3 mg for methadone and 7.0 mg for buprenorphine. Employment (46.3% of patients had a salary), dwelling and family live (46.3% of patients were in charge of children) were favored. Nevertheless, precariousness persisted: 32% of patients were indebted and help of social workers was not systematically searched. One third of the patients were alcohol and cannabis misusers, 70% were smoking and 34.5% multiple drug misusers. An important number of patients were taking anxiolytics (37.8%) and hypnotics (30.5%). After 10 years of follow-up for an ORR by a GP, the social situation of patients seems to have stabilized, but psychoactive drugs consumption remains important. Copyright © 2016 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

Superexchange Effects on Oxygen Reduction Activity of Edge-Sharing [Cox Mn1-x O6 ] Octahedra in Spinel Oxide.

PubMed

Zhou, Ye; Sun, Shengnan; Xi, Shibo; Duan, Yan; Sritharan, Thirumany; Du, Yonghua; Xu, Zhichuan J

2018-03-01

Mn-Co containing spinel oxides are promising, low-cost electrocatalysts for the oxygen reduction reaction (ORR). Most studies are devoted to the design of porous Mn-Co spinels or to strongly coupled hybrids (e.g., MnCo 2 O 4 /N-doped-rmGO) to maximize the mass efficiency. The lack of analyses by metal oxide intrinsic activity (activity normalized to catalysts' surface area) hinders the development of fundamental understanding of the physicochemical principles behind the catalytic activities. A systematic study on the composition dependence of ORR in ZnCo x Mn 2- x O 4 (x = 0.0-2.0) spinel is presented here with special attention to the role of edge sharing [Co x Mn 1- x O 6 ] octahedra in the spinel structure. The ORR specific activity of ZnCo x Mn 2- x O 4 spans across a potential window of 200 mV, indicating an activity difference of ≈3 orders of magnitude. The curve of composition-dependent ORR specific activity as a function of Co substitution exhibits a volcano shape with an optimum Mn/Co ratio of 0.43. It is revealed that the modulated e g occupancy of active Mn cations (0.3-0.9), as a consequence of the superexchange effect between edge sharing [CoO 6 ] and [MnO 6 ], reflects the ORR activity of edge sharing [Co x Mn 1- x O 6 ] octahedra in the ZnCo x Mn 2- x O 4 spinel oxide. These findings offer crucial insights in designing spinel oxide catalysts with fine-tuned e g occupancy for efficient catalysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modified Graphene as Electrocatalyst towards Oxygen Reduction Reaction for Fuel Cells

NASA Astrophysics Data System (ADS)

Qazzazie, D.; Beckert, M.; Mülhaupt, R.; Yurchenko, O.; Urban, G.

2014-11-01

This paper reports modified graphene-based materials as metal-free electrocatalysts for oxygen reduction reaction (ORR) with outstanding electrocatalytic activity in alkaline conditions. Nitrogen-doped graphene samples are synthesized by a novel procedure. The defect density in the structure of the prepared materials is investigated by Raman spectroscopy. Further structural characterization by X-ray photoelectron spectroscopy reveals the successful nitrogen doping of graphene. The electrochemical characterization of graphene and nitrogen-doped graphene in 0.1 M KOH solution demonstrates the material's electrocatalytic activity towards ORR. For graphene an onset potential of - 0.175 V vs. Ag/AgCl reference electrode is determined, while for nitrogen-doped graphene the determined onset potential is - 0.160 V. Thus, the electrocatalytic activity of nitrogen-doped graphene towards ORR is enhanced which can be ascribed to the effect of nitrogen doping.

Suppression of oxygen reduction reaction activity on Pt-based electrocatalysts from ionomer incorporation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shinozaki, Kazuma; Morimoto, Yu; Pivovar, Bryan S.

The impact of Nafion on the oxygen reduction reaction (ORR) activity is studied for Pt/C and Pt-alloy/C catalysts using thin-film rotating disk electrode (TF-RDE) methods in 0.1 M HClO4. Ultrathin uniform catalyst layers and standardized activity measurement protocols are employed to obtain accurate and reproducible ORR activity. Nafion lowers the ORR activity which plateaus with increasing loading on Pt catalysts. Pt particle size is found not to have significant influence on the extent of the SA decrease upon Nafion incorporation. Catalysts using high surface area carbon (HSC) support exhibit attenuated activity loss resulting from lower ionomer coverage on catalyst particlesmore » located within the deep pores. The impact of metallic composition on the activity loss due to Nafion incorporation is also discussed.« less

Shedding Light on the Oxygen Reduction Reaction Mechanism in Ether-Based Electrolyte Solutions: A Study Using Operando UV-Vis Spectroscopy.

PubMed

Hirshberg, Daniel; Sharon, Daniel; Afri, Michal; Lavi, Ronit; Frimer, Aryeh A; Metoki, Noa; Eliaz, Noam; Kwak, Won-Jin; Sun, Yang-Kook; Aurbach, Doron

2018-04-04

Using UV-vis spectroscopy in conjunction with various electrochemical techniques, we have developed a new effective operando methodology for investigating the oxygen reduction reactions (ORRs) and their mechanisms in nonaqueous solutions. We can follow the in situ formation and presence of superoxide moieties during ORR as a function of solvent, cations, anions, and additives in the solution. Thus, using operando UV-vis spectroscopy, we found evidence for the formation of superoxide radical anions during oxygen reduction in LiTFSI/diglyme electrolyte solutions. Nitro blue tetrazolium (NBT) was used to indicate the presence of superoxide moieties based on its unique spectral response. Indeed, the spectral response of NBT containing solutions undergoing ORR could provide a direct indication for the level of association of the Li cations with the electrolyte anions.

Axitinib after Sunitinib in Metastatic Renal Cancer: Preliminary Results from Italian "Real-World" SAX Study.

PubMed

D'Aniello, Carmine; Vitale, Maria G; Farnesi, Azzurra; Calvetti, Lorenzo; Laterza, Maria M; Cavaliere, Carla; Della Pepa, Chiara; Conteduca, Vincenza; Crispo, Anna; De Vita, Ferdinando; Grillone, Francesco; Ricevuto, Enrico; De Tursi, Michele; De Vivo, Rocco; Di Napoli, Marilena; Cecere, Sabrina C; Iovane, Gelsomina; Amore, Alfonso; Piscitelli, Raffaele; Quarto, Giuseppe; Pisconti, Salvatore; Ciliberto, Gennaro; Maiolino, Piera; Muto, Paolo; Perdonà, Sisto; Berretta, Massimiliano; Naglieri, Emanuele; Galli, Luca; Cartenì, Giacomo; De Giorgi, Ugo; Pignata, Sandro; Facchini, Gaetano; Rossetti, Sabrina

2016-01-01

Axitinib is an oral angiogenesis inhibitor, currently approved for treatment of metastatic renal cell carcinoma (mRCC) after failure of prior treatment with Sunitinib or cytokine. The present study is an Italian Multi-Institutional Retrospective Analysis that evaluated the outcomes of Axitinib, in second-line treatment of mRCC. The medical records of 62 patients treated with Axitinib, were retrospectively reviewed. The Progression Free Survival (PFS), the Overall Survival (OS), the Objective Response Rate (ORR), the Disease Control Rate (DCR), and the safety profile of axitinib and sunitinib-axitinib sequence, were the primary endpoint. The mPFS was 5.83 months (95% CI 3.93-7.73 months). When patients was stratified by Heng score, mPFS was 5.73, 5.83, 10.03 months according to poor, intermediate, and favorable risk group, respectively. The mOS from the start of axitinib was 13.3 months (95% CI 8.6-17.9 months); the observed ORR and DCR were 25 and 71%, respectively. When stratified patients by subgroups defined by duration of prior therapy with Sunitinib (≤ vs. >median duration), there was a statistically significant difference in mPFS with 8.9 (95% CI 4.39-13.40 months) vs. 5.46 months (95% CI 4.04-6.88 months) for patients with a median duration of Sunitinib >13.2 months. DCR and ORR to previous Sunitinib treatment was associated with longer statistically mPFS, 7.23 (95% CI 3.95-10.51 months, p = 0.01) and 8.67 (95% CI 4.0-13.33 months, p = 0.008) vs. 2.97 (95% CI 0.65-5.27 months, p = 0.01) and 2.97 months (95% CI 0.66-5.28 months, p = 0.01), respectively. Overall Axitinib at standard schedule of 5 mg bid, was well-tolerated. The most common adverse events of all grades were fatig (25.6%), hypertension (22.6%), gastro-intestinal disorders (25.9%), and hypothyroidism (16.1%). The sequence Sunitinib-Axitinib was well-tolerated without worsening in side effects, with a median OS of 34.7 months (95% CI 18.4-51.0 months). Our results are consistent with the available literature; this retrospective analysis confirms that Axitinib is effective and safe in routine clinical practice.

A Philosophical Analysis of David Orr's Theory of Ecological Literacy: Biophilia, Ecojustice and Moral Education in School Learning Communities

ERIC Educational Resources Information Center

Mitchell, Debra B.; Mueller, Michael P.

2011-01-01

In his writings, David Orr claims that the US is in an "ecological crisis" and that this stems from a crisis of education. He outlines a theory of ecological literacy, a mode by which we better learn the ecology of the Earth and live in a sustainable manner. While emphasizing a shock doctrine, the diagnosis of "crisis" may be…

Oxygen reduction reaction activity and structural stability of Pt-Au nanoparticles prepared by arc-plasma deposition.

PubMed

Takahashi, Shuntaro; Chiba, Hiroshi; Kato, Takashi; Endo, Shota; Hayashi, Takehiro; Todoroki, Naoto; Wadayama, Toshimasa

2015-07-28

The oxygen reduction reaction (ORR) activity and durability of various Au(x)/Pt100 nanoparticles (where x is the atomic ratio of Au against Pt) are evaluated herein. The samples were fabricated on a highly-oriented pyrolytic graphite substrate at 773 K through sequential arc-plasma depositions of Pt and Au. The electrochemical hydrogen adsorption charges (electrochemical surface area), particularly the characteristic currents caused by the corner and edge sites of the Pt nanoparticles, decrease with increasing Au atomic ratio (x). In contrast, the specific ORR activities of the Au(x)/Pt100 samples were dependent on the atomic ratios of Pt and Au: the Au28/Pt100 sample showed the highest specific activity among all the investigated samples (x = 0-42). As for ORR durability evaluated by applying potential cycles between 0.6 and 1.0 V in oxygen-saturated 0.1 M HClO4, Au28/Pt100 was the most durable sample against the electrochemical potential cycles. The results clearly showed that the Au atoms located at coordinatively-unsaturated sites, e.g. at the corners or edges of the Pt nanoparticles, can improve the ORR durability by suppressing unsaturated-site-induced degradation of the Pt nanoparticles.

Perovskite/Carbon Composites: Applications in Oxygen Electrocatalysis.

PubMed

Zhu, Yinlong; Zhou, Wei; Shao, Zongping

2017-03-01

Oxygen electrocatalysis, i.e., oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), plays an extremely important role in oxygen-based renewable-energy technologies such as rechargeable metal-air batteries, regenerative fuel cells and water splitting. Perovskite oxides have recently attracted increasing interest and hold great promise as efficient ORR and OER catalysts to replace noble-metal-based catalysts, owing to their high intrinsic catalytic activity, abundant variety, low cost, and rich resources. The introduction of perovskite-carbon interfaces by forming perovskite/carbon composites may bring a synergistic effect between the two phases, thus benefiting the oxygen electrocatalysis. This review provides a comprehensive overview of recent advances in perovskite/carbon composites for oxygen electrocatalysis in alkaline media, aiming to provide insights into the key parameters that influence the ORR/OER performance of the composites, including the physical/chemical properties and morphologies of the perovskites, the multiple roles of carbon, the synthetic method and the synergistic effect. A special emphasis is placed on the origin of the synergistic effect associated with the interfacial interaction between the perovskite and the carbon phases for enhanced ORR/OER performance. Finally, the existing challenges and the future directions for the synthesis and development of more efficient oxygen catalysts based on perovskite/carbon composites are proposed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-Potential Electrocatalytic O2 Reduction with Nitroxyl/NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

PubMed Central

2015-01-01

Efficient reduction of O2 to water is a central challenge in energy conversion and many aerobic oxidation reactions. Here, we show that the electrochemical oxygen reduction reaction (ORR) can be achieved at high potentials by using soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl (TEMPO), nor NOx species, such as sodium nitrite, are effective ORR mediators. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction with overpotentials as low as 300 mV in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The overpotentials accessible with this ORR system are significantly lower than widely studied molecular metal-macrocycle ORR catalysts and benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. PMID:27162977

Post-formation copper-nitrogen species on carbon black: their chemical structures and active sites for oxygen reduction reaction.

PubMed

Xie, Xin; Liu, Jingjun; Li, Tuanfeng; Song, Ye; Wang, Feng

2018-05-16

Note that 3d transition metal and nitrogen co-doped carbon materials (TM-N-C) are considered as the most promising next-generation electrocatalysts alternative to precious Pt for oxygen reduction reaction (ORR). Herein, we have fabricated a Cu-N-C catalyst through directly grafting copper-nitrogen complexes composed by cuprous chloride and ammonia water onto the surface of an industrial carbon black at 500℃. In an alkaline environment, the synthesized catalyst exhibits excellent ORR catalytic activity, which is comparable to the state-of-the-art Pt/C catalyst but far exceeding that obtained by the original carbon. Moreover, the catalyst displays much better stability than the Pt/C. The enhanced ORR performance is proven to originate from the post-formation Cu(I)-N2 and Cu(II)-N4 sites at the carbon surface, as evidenced by X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The possible ORR process catalyzed by these Cu-Nx species is discussed at atomic level. This work provides a simple and fast synthesis strategy for efficient TM-N-C catalysts on a large scale for energy storage and conversion systems. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemically reduced graphene-oxide supported bimetallic nanoparticles highly efficient for oxygen reduction reaction with excellent methanol tolerance

NASA Astrophysics Data System (ADS)

Yasmin, Sabina; Cho, Sung; Jeon, Seungwon

2018-03-01

We report a simple and facile method for the fabrication of bimetallic nanoparticles on electrochemically reduced graphene oxide (ErGO) for electrocatalytic oxygen reduction reaction (ORR) in alkaline media. First, reduced graphene oxide supported palladium and manganese oxide nanoparticle (rGO/Pd-Mn2O3) catalyst was synthesized via a simple chemical method at room temperature; then, it was electrochemically reduced for oxidation reduction reaction (ORR) in alkaline media. The chemical composition and morphological properties of ErGO/Pd-Mn2O3 was characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). The TEM images reveals that, nano-sized Pd and Mn2O3 particles were disperse on the ErGO sheet without aggregation. The as-prepared ErGO/Pd-Mn2O3 was employed for ORR in alkaline media which shows higher ORR activity with more positive onset and half-wave potential, respectively. Remarkably, ErGO/Pd-Mn2O3 reduced oxygen via four-electron transfer pathway with negligible amount of intermediate peroxide species (HO2-). Furthermore, the higher stability and excellent methanol tolerance of the ErGO/Pd-Mn2O3 compared to commercial Pt/C (20 wt%) catalyst, indicating its suitability for fuel cells.

Carbon-supported Pd-Co as cathode catalyst for APEMFCs and validation by DFT.

PubMed

Maheswari, S; Karthikeyan, S; Murugan, P; Sridhar, P; Pitchumani, S

2012-07-21

Carbon supported PdCo catalysts in varying atomic ratios of Pd to Co, namely 1 : 1, 2 : 1 and 3 : 1, were prepared. The oxygen reduction reaction (ORR) was studied on commercial carbon-supported Pd and carbon-supported PdCo nanocatalysts in aqueous 0.1 M KOH solution with and without methanol. The structure, dispersion, electrochemical characterization and surface area of PdCo/C were determined by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Cyclic Voltammetry (CV), respectively. The electrochemical activity for ORR was evaluated from Linear Sweep Voltammograms (LSV) obtained using a rotating ring disk electrode. The catalysts were evaluated for their electrocatalytic activity towards oxygen reduction reaction (ORR) in Alkaline Polymer Electrolyte Membrane Fuel Cells (APEMFCs). PdCo(3 : 1)/C gives higher performance (85 mW cm(-2)) than PdCo(1 : 1)/C, PdCo(2 : 1)/C and Pd/C. The maximum electrocatalytic activity for ORR in the presence of methanol was observed for PdCo(3 : 1)/C. First principles calculations within the framework of density functional theory were performed to understand the origin of its catalytic activity based on the energy of adsorption of an O(2) molecule on the cluster, structural variation and charge transfer mechanism.

Nitrogen-doped porous carbon nanosheets made from biomass as highly active electrocatalyst for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Pan, Fuping; Cao, Zhongyue; Zhao, Qiuping; Liang, Hongyu; Zhang, Junyan

2014-12-01

The successful commercialization of fuel cells requires the efficient electrocatalyst to make the oxygen reduction reaction (ORR) fast because of the sluggish nature of ORR and the high cost of the platinum catalysts. In this work, we report the excellent performance of metal-free nitrogen-doped porous carbon nanosheets (NPCN) with hierarchical porous structure and a high surface area of 1436.02 m2 g-1 for catalyzing ORR. The active NPCN is synthesized via facile high-temperature carbonization of natural ginkgo leaves followed by purification and ammonia post-treatment without using additional supporting templates and activation processes. In O2-saturated 0.1 M KOH solution, the resultant NPCN exhibits a high kinetic-limiting current density of 13.57 mA cm-2 at -0.25 V (vs. Ag/AgCl) approaching that of the commercial Pt/C catalyst (14 mA cm-2) and long-term electrochemical stability. Notably, the NPCN shows a slightly negative ORR half-wave potential in comparison with Pt/C (ΔE1/2 = 19 mV). The excellent electrocatalytic properties of NPCN originate from the combined effect of optimal nitrogen doping, high surface area, and porous architecture, which induce the high-density distribution of highly active and stable catalytic sites.

Hemoglobin-carbon nanotube derived noble-metal-free Fe5C2-based catalyst for highly efficient oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Vij, Varun; Tiwari, Jitendra N.; Lee, Wang-Geun; Yoon, Taeseung; Kim, Kwang S.

2016-02-01

High performance non-precious cathodic catalysts for oxygen reduction reaction (ORR) are vital for the development of energy materials and devices. Here, we report an noble metal free, Fe5C2 nanoparticles-studded sp2 carbon supported mesoporous material (CNTHb-700) as cathodic catalyst for ORR, which was prepared by pyrolizing the hybrid adduct of single walled carbon nanotubes (CNT) and lyophilized hemoglobin (Hb) at 700 °C. The catalyst shows onset potentials of 0.92 V in 0.1 M HClO4 and in 0.1 M KOH which are as good as commercial Pt/C catalyst, giving very high current density of 6.34 and 6.69 mA cm-2 at 0.55 V vs. reversible hydrogen electrode (RHE), respectively. This catalyst has been confirmed to follow 4-electron mechanism for ORR and shows high electrochemical stability in both acidic and basic media. Catalyst CNTHb-700 possesses much higher tolerance towards methanol than the commercial Pt/C catalyst. Highly efficient catalytic properties of CNTHb-700 could lead to fundamental understanding of utilization of biomolecules in ORR and materialization of proton exchange membrane fuel cells for clean energy production.

Improving Pool Fencing Legislation in Queensland, Australia: Attitudes and Impact on Child Drowning Fatalities

PubMed Central

2017-01-01

Four-sided, non-climbable pool fencing is an effective strategy for preventing children from drowning in home swimming pools. In 2009, the Queensland Government introduced legislation to improve the effectiveness of pool fencing. This study explores community attitudes towards the effectiveness of these legislative changes and examines child (<5 years) drowning deaths in pools. Data from the 2011 Queensland Computer-Assisted Telephone Interviewing (CATI) Social Survey include results from questions related to pool ownership and pool fencing legislation. Fatal child drowning cases between 1 January 2005 and 31 December 2015 were sourced from coronial data. Of the 1263 respondents, 26/100 households had a pool. A total of 58% believed tightening legislation would be effective in reducing child drowning deaths. Pool owners were more likely to doubt the effectiveness of legislation (p < 0.001) when compared to non-pool owners. Perceptions of effectiveness did not differ by presence of children under the age of five. There were 46 children who drowned in Queensland home pools (7.8/100,000 pools with children residing in the residence/annum) between 2005 and 2015. While pool owners were less likely to think that tightening the legislation would be effective, the number of children drowning in home swimming pools declined over the study period. Drowning prevention agencies have more work to do to ensure that the most vulnerable (young children in houses with swimming pools) are protected. PMID:29186787

Exploratory cohort study and meta-analysis of BIM deletion polymorphism in patients with epidermal growth factor receptor-mutant non-small-cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitors

PubMed Central

Sun, Si; Yu, Hui; Wang, Huijie; Zhao, Xinmin; Zhao, Xintai; Wu, Xianghua; Qiao, Jie; Chang, Jianhua; Wang, Jialei

2017-01-01

Background Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations might develop primary and secondary resistance to tyrosine kinase inhibitors (TKIs). The proapoptotic protein Bcl-2-like 11 (BIM) is a key modulator of apoptosis triggered by EGFR-TKIs. The recent studies have indicated that some patients with positive EGFR mutations were refractory to EGFR-TKIs if they harbored a BIM deletion polymorphism. The purpose of this study was to investigate whether BIM polymorphism predicts treatment efficacy of EGFR-TKIs in Chinese NSCLC patients. Patients and methods A cohort of advanced NSCLC patients with EGFR mutations and treated with EGFR-TKIs (gefitinib or erlotinib) were recruited. We drew peripheral blood to determinate BIM deletion status and then compared patients’ clinical outcomes according to the BIM deletion status. Additionally, we electronically searched eligible cohort studies and conducted a meta-analysis to pool event risk. Results The exploratory cohort study included 140 patients. Patients with and without the BIM deletion polymorphism had similar objective response rates (ORRs, 48.5 vs 63.0%, P=0.16), disease control rate (DCR, 93.9 vs 97.0%, P=0.60) and adverse reactions. Similar progression-free survival (PFS) and overall survival (OS) were noted in overall population (P=0.27 for PFS and P=0.61 for OS) and prespecified patient subgroups. The meta-analysis included 10 eligible cohort studies involving 1,317 NSCLC patients. It showed the positive BIM deletion was associated with shorter PFS (hazard ratio =1.45; P=0.02). Nonsignificant differences existed for ORR, DCR and OS. Conclusion The expanded meta-analysis results demonstrated the positive BIM deletion predicts shorter PFS in NSCLC patients after treatment with EGFR-TKIs while other clinical measures do not. A large multicenter well-designed cohort study involving other concurrent genetic alterations is warranted. PMID:28435285

Exploratory cohort study and meta-analysis of BIM deletion polymorphism in patients with epidermal growth factor receptor-mutant non-small-cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitors.

PubMed

Sun, Si; Yu, Hui; Wang, Huijie; Zhao, Xinmin; Zhao, Xintai; Wu, Xianghua; Qiao, Jie; Chang, Jianhua; Wang, Jialei

2017-01-01

Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor ( EGFR ) mutations might develop primary and secondary resistance to tyrosine kinase inhibitors (TKIs). The proapoptotic protein Bcl-2-like 11 (BIM) is a key modulator of apoptosis triggered by EGFR-TKIs. The recent studies have indicated that some patients with positive EGFR mutations were refractory to EGFR-TKIs if they harbored a BIM deletion polymorphism. The purpose of this study was to investigate whether BIM polymorphism predicts treatment efficacy of EGFR-TKIs in Chinese NSCLC patients. A cohort of advanced NSCLC patients with EGFR mutations and treated with EGFR-TKIs (gefitinib or erlotinib) were recruited. We drew peripheral blood to determinate BIM deletion status and then compared patients' clinical outcomes according to the BIM deletion status. Additionally, we electronically searched eligible cohort studies and conducted a meta-analysis to pool event risk. The exploratory cohort study included 140 patients. Patients with and without the BIM deletion polymorphism had similar objective response rates (ORRs, 48.5 vs 63.0%, P =0.16), disease control rate (DCR, 93.9 vs 97.0%, P =0.60) and adverse reactions. Similar progression-free survival (PFS) and overall survival (OS) were noted in overall population ( P =0.27 for PFS and P =0.61 for OS) and prespecified patient subgroups. The meta-analysis included 10 eligible cohort studies involving 1,317 NSCLC patients. It showed the positive BIM deletion was associated with shorter PFS (hazard ratio =1.45; P =0.02). Nonsignificant differences existed for ORR, DCR and OS. The expanded meta-analysis results demonstrated the positive BIM deletion predicts shorter PFS in NSCLC patients after treatment with EGFR-TKIs while other clinical measures do not. A large multicenter well-designed cohort study involving other concurrent genetic alterations is warranted.

Electrocatalytic activity of silver decorated ceria microspheres for the oxygen reduction reaction and their application in aluminium-air batteries.

PubMed

Sun, Shanshan; Xue, Yejian; Wang, Qin; Li, Shihua; Huang, Heran; Miao, He; Liu, Zhaoping

2017-07-11

Nanosheet-constructing porous CeO 2 microspheres with silver nanoparticles anchored on the surface were developed as a highly efficient oxygen reduction reaction (ORR) catalyst. The aluminum-air batteries applying Ag-CeO 2 as the ORR catalyst exhibit a high output power density and low degradation rate of 345 mW cm -2 and 2.6% per 100 h, respectively.

Three-Dimensional Structure of Boundary Layers in Transition to Turbulence

DTIC Science & Technology

1989-03-01

step-by-step Orr- Sommerfeld solution and integration. What is needed is an initial condition and initial wavenumber. These data can be obtained from a ...general than unsteady boundary-layer equations and Orr- Sommerfeld equation which are special cases. There- fore, the PSE will be a valuable tool for...spectra (discrete, continuous) result in a given problem is discussed in monographs and journal articles. Here, we try to find solutions to the

Janus structured Pt–FeNC nanoparticles as a catalyst for the oxygen reduction reaction

DOE PAGES

Kuttiyiel, Kurian A.; Sasaki, Kotaro; Park, Gu -Gon; ...

2017-01-03

Here, we present a new Janus structured catalyst consisting of Pt nanoparticles on Fe–N–C nanoparticles encapsulated by graphene layers for the ORR. The ORR activity of the catalyst increases under potential cycling as the unique Janus nanostructure is further bonded due to a synergetic effect. The present study describes an important advanced approach for the future design of efficient, stable, and low-cost Pt-based electrocatalytic systems.

Durability enhancement of intermetallics electrocatalysts via N-anchor effect for fuel cells.

PubMed

Li, Xiang; An, Li; Chen, Xin; Zhang, Nanlin; Xia, Dingguo; Huang, Weifeng; Chu, Wangsheng; Wu, Ziyu

2013-11-18

Insufficient durability and catalytic activity of oxygen reduction reaction (ORR) electrocatalyst are key issues that have to be solved for the practical application of low temperature fuel cell. This paper introduces a new catalyst design strategy using N-anchor to promote the corrosion resistance of electrocatalyst. The as-synthesized N-Pt3Fe1/C shows a high electrocatalytic activity and a superior durability towards ORR. The kinetic current density of N-Pt3Fe1/C as normalized by ECSA is still as high as 0.145 mA cm(-2) and only 7% loss after 20,000 potential cycles from 0.6 to 1.2 V (vs. NHE) in O2-bubbling perchloric acid solution, whereas Pt3Fe1/C shows 49% loss under the same tests. The N-anchor approach offers novel opportunities for the development of ORR catalyst with excellent electrochemical properties.

Nafion induced surface confinement of oxygen in carbon-supported oxygen reduction catalysts

DOE PAGES

Chlistunoff, Jerzy; Sansinena, Jose -Maria

2016-11-17

We studied the surface confinement of oxygen inside layers of Nafion self-assembled on carbon-supported oxygen reduction reaction (ORR) catalysts. It is demonstrated that oxygen accumulates in the hydrophobic component of the polymer remaining in contact with the carbon surface. Furthermore, the amount of surface confined oxygen increases with the degree of carbon surface graphitization, which promotes the self-assembly of the polymer. Planar macrocyclic ORR catalysts possessing a delocalized system of π electrons such as Co and Fe porphyrins and phthalocyanines have virtually no effect on the surface confinement of oxygen, in accordance with their structural similarity to graphitic carbon surfacesmore » where they adsorb. Platinum particles in carbon-supported ORR catalysts with high metal contents (20%) disrupt the self-assembly of Nafion and virtually eliminate the oxygen confinement, but the phenomenon is still observed for low Pt loading (4.8%) catalysts.« less

Bifunctional Nitrogen-Doped Microporous Carbon Microspheres Derived from Poly(o-methylaniline) for Oxygen Reduction and Supercapacitors.

PubMed

He, Yanzhen; Han, Xijiang; Du, Yunchen; Song, Bo; Xu, Ping; Zhang, Bin

2016-02-17

Heteroatom-doped carbon materials have attracted significant attention because of their applications in oxygen reduction reaction (ORR) and supercapacitors. Here we demonstrate a facile poly(o-methylaniline)-derived fabrication of bifunctional microporous nitrogen-doped carbon microspheres (NCMSs) with high electrocatalytic activity and stability for ORR and energy storage in supercapacitors. At a pyrolysis temperature of 900 °C, the highly dispersed NCMSs present a high surface area (727.1 m(2) g(-1)), proper total content of doping N, and high concentration of quaternary N, which exhibit superior electrocatalytic activities for ORR to the commercial Pt/C catalysts, high specific capacitance (414 F g(-1)), and excellent durability, making them very promising for advanced energy conversion and storage. The presented conducting polymer-derived strategy may provide a new way for the fabrication of heteroatom-doped carbon materials for energy device applications.

Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte

PubMed Central

Huang, K.; Bi, K.; Liang, C.; Lin, S.; Zhang, R.; Wang, W. J.; Tang, H. L.; Lei, M.

2015-01-01

A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells. PMID:26100367

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chlistunoff, Jerzy; Pivovar, Bryan

In this paper, the oxygen reduction reaction (ORR) at the interface between platinum and Nafion 1100 equivalent weight was studied as a function of temperature (20–80 °C), humidity (10–100%), scan rate, the manner in which Nafion film was deposited, and the state of the Pt surface using ultramicroelectrodes employing cyclic voltammetry and chronoamperometry. ORR on smooth electrodes was strongly inhibited under specific conditions dependent on temperature, humidity, and scan rate. From the data presented, we postulate that dynamic changes in the molecular structure of the ionomer at the platinum interface result in differences in ORR voltammetry for films prepared andmore » equilibrated under different conditions. The lack of similar changes for rough, platinized electrodes has been attributed to differences in initial ionomer structure and a higher energy barrier for ionomer restructuring. Finally, these model system studies yield insight into the ionomer-catalyst interface of particular interest for polymer electrolyte fuel cells.« less

Rational design of competitive electrocatalysts for the oxygen reduction reaction in hydrogen fuel cells

NASA Astrophysics Data System (ADS)

Stolbov, Sergey; Alcántara Ortigoza, Marisol

2012-02-01

The large-scale application of one of the most promising clean and renewable sources of energy, hydrogen fuel cells, still awaits efficient and cost-effective electrocatalysts for the oxygen reduction reaction (ORR) occurring on the cathode. We demonstrate that truly rational design renders electrocatalysts possessing both qualities. By unifying the knowledge on surface morphology, composition, electronic structure and reactivity, we solve that sandwich-like structures are an excellent choice for optimization. Their constituting species couple synergistically yielding reaction-environment stability, cost-effectiveness and tunable reactivity. This cooperative-action concept enabled us to predict two advantageous ORR electrocatalysts. Density functional theory calculations of the reaction free-energy diagrams confirm that these materials are more active toward ORR than the so far best Pt-based catalysts. Our designing concept advances also a general approach for engineering materials in heterogeneous catalysis.

The mechanisms of oxygen reduction and evolution reactions in nonaqueous lithium-oxygen batteries.

PubMed

Cao, Ruiguo; Walter, Eric D; Xu, Wu; Nasybulin, Eduard N; Bhattacharya, Priyanka; Bowden, Mark E; Engelhard, Mark H; Zhang, Ji-Guang

2014-09-01

A fundamental understanding of the mechanisms of both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in nonaqueous lithium-oxygen (Li-O2) batteries is essential for the further development of these batteries. In this work, we systematically investigate the mechanisms of the ORR/OER reactions in nonaqueous Li-O2 batteries by using electron paramagnetic resonance (EPR) spectroscopy, using 5,5-dimethyl-pyrroline N-oxide as a spin trap. The study provides direct verification of the formation of the superoxide radical anion (O2(˙-)) as an intermediate in the ORR during the discharge process, while no O2(˙-) was detected in the OER during the charge process. These findings provide insight into, and an understanding of, the fundamental reaction mechanisms involving oxygen and guide the further development of this field. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phosphine-functionalized graphene oxide, a high-performance electrocatalyst for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Ensafi, Ali A.; Golbon Haghighi, Mohsen; Jafari-Asl, Mehdi

2018-01-01

Here, a new approach for the synthesis of phosphine-functionalized graphene oxide (GO-PPh2) was developed. Using a simple method, diphenylphosphine group was linked to the hydroxyl group of OH-functionalized graphene that existing at the graphene surface. The electrochemical activity of GO-PPh2 for electrochemical oxygen reduction was checked. The results demonstrated that the new carbon hybrid material has a powerful potential for electrochemical oxygen reduction reaction (ORR). Moreover, GO-PPh2 as an electrocatalyst for ORR exhibited tolerance for methanol or ethanol as a result of crossover effect. In comparison with commercial Pt/C and Pt/rGO electrocatalysts, results showed that GO-PPh2 has a much higher selectivity, better durability, and much better electrochemical stability towards the ORR. The proposed method based on GO-PPh2 introduce an efficient electrocatalyst for further application in fuel cells.

Boron and oxygen-codoped porous carbon as efficient oxygen reduction catalysts

NASA Astrophysics Data System (ADS)

Lei, Zhidan; Chen, Hongbiao; Yang, Mei; Yang, Duanguang; Li, Huaming

2017-12-01

A low-cost boron- and oxygen-codoped porous carbon electrocatalyst towards oxygen reduction reaction (ORR) has been fabricated by a facile one-step pyrolysis approach, while a boron- and oxygen-rich polymer network was used as precursor. The boron- and oxygen-codoped carbon catalyst with high ORR electrocatalytic activity is comparable to that of Pt/C and is superior to that of catalysts doped solely with boron atoms or with oxygen atoms. Furthermore, the optimized boron- and oxygen-codoped carbon catalyst possesses excellent methanol tolerance and long-term durability in alkaline media. The high electrocatalytic activity of the dual-doped carbon catalysts can be attributed to the synergistic effects of high surface area, predominant mesostructure, abundant active oxygen-containing groups, and effective boron doping. The present results show that this boron- and oxygen-codoping strategy could be as a promising way for the preparation of highly efficient ORR catalysts.

Nafion induced surface confinement of oxygen in carbon-supported oxygen reduction catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chlistunoff, Jerzy; Sansinena, Jose -Maria

We studied the surface confinement of oxygen inside layers of Nafion self-assembled on carbon-supported oxygen reduction reaction (ORR) catalysts. It is demonstrated that oxygen accumulates in the hydrophobic component of the polymer remaining in contact with the carbon surface. Furthermore, the amount of surface confined oxygen increases with the degree of carbon surface graphitization, which promotes the self-assembly of the polymer. Planar macrocyclic ORR catalysts possessing a delocalized system of π electrons such as Co and Fe porphyrins and phthalocyanines have virtually no effect on the surface confinement of oxygen, in accordance with their structural similarity to graphitic carbon surfacesmore » where they adsorb. Platinum particles in carbon-supported ORR catalysts with high metal contents (20%) disrupt the self-assembly of Nafion and virtually eliminate the oxygen confinement, but the phenomenon is still observed for low Pt loading (4.8%) catalysts.« less

Co@Co3O4 nanoparticle embedded nitrogen-doped carbon architectures as efficient bicatalysts for oxygen reduction and evolution reactions

NASA Astrophysics Data System (ADS)

Qi, Chunling; Zhang, Li; Xu, Guancheng; Sun, Zhipeng; Zhao, Aihua; Jia, Dianzeng

2018-01-01

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play crucial roles in efficient energy conversion and storage solutions. Here, Co@Co3O4 nanoparticle embedded nitrogen-doped carbon architectures (denoted as Co@Co3O4/NCs) are prepared via a simple two-step and in situ approach by carbonization and subsequent oxidation of Co-MOF containing high contents of carbon and nitrogen. When evaluated as electrocatalyst towards both ORR and OER in a KOH electrolyte solution, the as-fabricated Co@Co3O4/NC-2 exhibits similar ORR catalytic activity to the commercial Pt/C catalyst, but superior stability and good methanol tolerance. Furthermore, the as-fabricated catalysts also show promising catalytic activity for OER. The effective catalytic activities originate from the synergistic effects between well wrapped Co@Co3O4 nanoparticles and nitrogen doped carbon structures.

Controllable synthesis of Co3O4 nanocrystals as efficient catalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Li, Baoying; Zhang, Yihe; Du, Ruifeng; Liu, Lei; Yu, Xuelian

2018-03-01

The electrochemical oxygen reduction reaction (ORR) has received great attention due to its importance in fuel cells and metal-air batteries. Here, we present a simple approach to prepare non-noble metal catalyst-Co3O4 nanocrystals (NCs). The particle size and shape were simply controlled by different types and concentrations of metal precursor. Furthermore, different sizes and shapes of Co3O4 NCs are explored as electrocatalysts for ORR, and it has been observed that particles with a similar shape, and smaller particle size led to greater catalytic current densities because of the greater surface area. For particles with a comparable size, the shape or crystalline structure governed the activity of the electrocatalytic reactions. Most importantly, the 9 nm-Co3O4 were demonstrated to act as low-cost catalysts for the ORR with a similar performance to that of Pt catalysts.

Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte

NASA Astrophysics Data System (ADS)

Huang, K.; Bi, K.; Liang, C.; Lin, S.; Zhang, R.; Wang, W. J.; Tang, H. L.; Lei, M.

2015-06-01

A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells.

Mass-Producible 2D-MoS2-Impregnated Screen-Printed Electrodes That Demonstrate Efficient Electrocatalysis toward the Oxygen Reduction Reaction.

PubMed

Rowley-Neale, Samuel J; Smith, Graham C; Banks, Craig E

2017-07-12

Two-dimensional molybdenum disulfide (2D-MoS 2 ) screen-printed electrodes (2D-MoS 2 -SPEs) have been designed, fabricated, and evaluated toward the electrochemical oxygen reduction reaction (ORR) within acidic aqueous media. A screen-printable ink has been developed that allows for the tailoring of the 2D-MoS 2 content/mass used in the fabrication of the 2D-MoS 2 -SPEs, which critically affects the observed ORR performance. In comparison to the graphite SPEs (G-SPEs), the 2D-MoS 2 -SPEs are shown to exhibit an electrocatalytic behavior toward the ORR which is found, critically, to be reliant upon the percentage mass incorporation of 2D-MoS 2 in the 2D-MoS 2 -SPEs; a greater percentage mass of 2D-MoS 2 incorporated into the 2D-MoS 2 -SPEs results in a significantly less electronegative ORR onset potential and a greater signal output (current density). Using optimally fabricated 2D-MoS 2 -SPEs, an ORR onset and a peak current of approximately +0.16 V [vs saturated calomel electrode (SCE)] and -1.62 mA cm -2 , respectively, are observed, which exceeds the -0.53 V (vs SCE) and -635 μA cm -2 performance of unmodified G-SPEs, indicating an electrocatalytic response toward the ORR utilizing the 2D-MoS 2 -SPEs. An investigation of the underlying electrochemical reaction mechanism of the ORR within acidic aqueous solutions reveals that the reaction proceeds via a direct four-electron process for all of the 2D-MoS 2 -SPE variants studied herein, where oxygen is electrochemically favorably reduced to water. The fabricated 2D-MoS 2 -SPEs are found to exhibit no degradation in the observed achievable current over the course of 1000 repeat scans. The production of such inks and the resultant mass-producible 2D-MoS 2 -SPEs mitigates the need to modify post hoc an electrode via the drop-casting technique that has been previously shown to result in a loss of achievable current over the course of 1000 repeat scans. The 2D-MoS 2 -SPEs designed, fabricated, and tested herein could have commercial viability as electrocatalytic fuel cell electrodes because of being economical as a result of their scales of economy and inherent tailorability. The technique utilized herein to produce the 2D-MoS 2 -SPEs could be adapted for the incorporation of different 2D nanomaterials, resulting in SPEs with the inherent advantages identified above.

Everolimus in Combination with Octreotide Long-Acting Repeatable in a First-Line Setting for Patients with Neuroendocrine Tumors: A 5-Year Update.

PubMed

Bajetta, Emilio; Catena, Laura; Pusceddu, Sara; Spada, Francesca; Iannacone, Claudio; Sarno, Italo; Di Menna, Giandomenico; Dottorini, Lorenzo; Marte, Anna Maria

2018-01-01

We previously presented data of this multicentric, phase II study showing that everolimus plus octreotide long-acting repeatable (LAR) for advanced neuroendocrine neoplasms (NENs), in the first line setting, is an active and safe treatment. We now present updated data at 5 years. Patients with advanced well-differentiated, previously untreated neuroendocrine tumors of the gastroenteropancreatic tract and of the lung received octreotide LAR 30 mg plus everolimus 10 mg/day. The primary endpoint was the objective response rate (ORR). We performed an analysis of "long responder" patients and of time to progression (TTP) and overall survival (OS) at 5 years. Fifty patients were enrolled; the primary tumor site was: pancreas (14 patients), lung (11 patients), ileum (9 patients), jejunum/duodenum (2 patients), and unknown (14 patients). Seventeen (34%) of these patients have received treatment for more than 2 years. The median exposure to study drugs was 519.5 days (range 48-2,024). Currently 3 patients are still in treatment. The ORR (partial response + complete response) was 18% (95% confidence interval [CI] 7.4-28.6): complete response 1 patient (2%), partial response 8 patients (16%), stable disease 37 patients (74%). The median TTP was 33.6 months (95% CI 18.7-41.2) and the median OS was 61.0 months (95% CI 49.8-not reached). In this update of clinical outcome at 5-year follow-up, everolimus plus octreotide has been shown to be active in advanced NENs. The current analysis showed a further prolongation of TTP and a long exposure to the study drug without major side effects in the long term. © 2017 S. Karger AG, Basel.

Modified biweekly cisplatin, docetaxel plus cetuximab (TPEx) as first-line treatment for patients with recurrent/metastatic head and neck cancer.

PubMed

Fuchs, Hannah; Pammer, Johannes; Minichsdorfer, Christoph; Posch, Doris; Kornek, Gabriela; Aretin, Marie-Bernadette; Fuereder, Thorsten

2018-02-07

Three weekly high-dose chemotherapy regimens in combination with weekly cetuximab are the treatment of choice for patients with recurrent/metastatic (R/M) head and neck squamous cell carcinoma (SCCHN), although the majority of patients suffer from severe side effects. Thus, we investigated the efficacy and safety of an alternative, more convenient and less toxic biweekly modified cisplatin, docetaxel plus cetuximab (TPEx) regimen in this retrospective analysis. Thirty-eight patients receiving off-protocol cisplatin (50 mg/m 2 ) in combination with docetaxel (50 mg/m 2 ) plus cetuximab (500 mg/m 2 ) every other week were included. Data collection included baseline demographic, response rate (ORR) and toxicity data as well as disease control rate, overall survival (OS) and progression-free survival (PFS). The median age was 60 years, and the majority of patients suffered from oral cavity carcinomas (44.7%) followed by oropharyngeal (28.9%) and laryngeal (17.9%) carcinomas. The ORR was 50%, and four (10.5%) patients achieved a complete response, while 15 (39.5%) patients had a partial response. The OS and PFS were 10.8 months (95% CI 6.7-14.2) and 6.3 months (95% CI 5.7-6.8), respectively. The one-year survival rate was 44.7%. The therapy was well tolerated, and the most common grade 3/4 adverse events were myelosuppression (13.2%), hypomagnesaemia (23.7%) and acne-like rash (13.1%). In conclusion, modified biweekly TPEx is of comparable efficacy with conventional TPEx and represents a well-tolerated regimen in R/M SCCHN patients. Further evaluation of this protocol in prospective clinical trials is warranted.

One Dimensional Graphitic Carbon Nitrides as Effective Metal-Free Oxygen Reduction Catalysts

PubMed Central

Tahir, Muhammad; Mahmood, Nasir; Zhu, Jinghan; Mahmood, Asif; Butt, Faheem K.; Rizwan, Syed; Aslam, Imran; Tanveer, M.; Idrees, Faryal; Shakir, Imran; Cao, Chuanbao; Hou, Yanglong

2015-01-01

To explore the effect of morphology on catalytic properties of graphitic carbon nitride (GCN), we have studied oxygen reduction reaction (ORR) performance of two different morphologies of GCN in alkaline media. Among both, tubular GCN react with dissolved oxygen in the ORR with an onset potential close to commercial Pt/C. Furthermore, the higher stability and excellent methanol tolerance of tubular GCN compared to Pt/C emphasizes its suitability for fuel cells. PMID:26201998

Roles of Mo Surface Dopants in Enhancing the ORR Performance of Octahedral PtNi Nanoparticles

DOE PAGES

Jia, Qingying; Zhao, Zipeng; Cao, Liang; ...

2017-12-22

Doping with a transition metal was recently shown to greatly boost the activity and durability of PtNi/C octahedral nanoparticles (NPs) for the oxygen reduction reaction (ORR), but its specific roles remain unclear. By combining electrochemistry, ex situ and in situ spectroscopic techniques, density functional theory calculations, and a newly developed kinetic Monte Carlo model, we showed that Mo atoms are preferentially located on the vertex and edge sites of Mo–PtNi/C in the form of oxides, which are stable within the wide potential window of the electrochemical cycle. These surface Mo oxides stabilize adjacent Pt sites, hereby stabilizing the octahedral shapemore » enriched with (111) facets, and lead to increased concentration of Ni in subsurface layers where they are protected against acid dissolution. Consequently, the favorable Pt 3Ni(111) structure for the ORR is stabilized on the surface of PtNi/C NPs in acid against voltage cycling. Significantly, the unusual potential-dependent oxygen coverage trend on Mo-doped PtNi/C NPs as revealed by the surface-sensitive Δμ analysis suggests that the Mo dopants may also improve the ORR kinetics by modifying the coordination environments of Pt atoms on the surface. Lastly, our studies point out a possible way to stabilize the favorable shape and composition established on conceptual catalytic models in practical nanoscale catalysts.« less

Environmentally Sensitive Areas Surveys Program threatened and endangered species survey: Progress report. Environmental Restoration Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, A.L.; Awl, D.J.; Gabrielsen, C.A.

The Endangered Species Act (originally passed in 1973) is a Federal statute that protects both animal and plant species. The Endangered Species Act identifies species which are, without careful management, in danger of becoming extinct and species that are considered threatened. Along with the designation of threatened or endangered, the Endangered Species Act provides for the identification of appropriate habitat for these species. Since 1993, the United States Department of Energy`s (DOE) Environmental Restoration (ER) Program has supported a program to survey the Oak Ridge Reservation (ORR) for threatened and endangered species. The Environmentally Sensitive Areas Surveys Program initiated vascularmore » plant surveys during fiscal year 1993 and vertebrate animal surveys during fiscal year 1994 to determine the baseline condition of threatened and endangered species on the ORR at the present time. Data collected during these surveys are currently aiding Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Remedial Investigations on the ORR. They also provide data for ER and Waste Management decision documents, ensure that decisions have technical and legal defensibility, provide a baseline for ensuring compliance with principal legal requirements and will increase public confidence in DOE`s adherence to all related environmental resources rules, laws, regulations, and instructions. This report discusses the progress to date of the threatened and endangered species surveys of the ORR.« less

Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique: I. Impact of Impurities, Measurement Protocols and Applied Corrections

DOE PAGES

Shinozaki, Kazuma; Zack, Jason W.; Richards, Ryan M.; ...

2015-07-22

The rotating disk electrode (RDE) technique is being extensively used as a screening tool to estimate the activity of novel PEMFC electrocatalysts synthesized in lab-scale (mg) quantities. Discrepancies in measured activity attributable to glassware and electrolyte impurity levels, as well as conditioning, protocols and corrections are prevalent in the literature. Moreover, the electrochemical response to a broad spectrum of commercially sourced perchloric acid and the effect of acid molarity on impurity levels and solution resistance were also assessed. Our findings reveal that an area specific activity (SA) exceeding 2.0 mA/cm 2 (20 mV/s, 25°C, 100 kPa, 0.1 M HClO 4)more » for polished poly-Pt is an indicator of impurity levels that do not impede the accurate measurement of the ORR activity of Pt based catalysts. After exploring various conditioning protocols to approach maximum utilization of the electrochemical area (ECA) and peak ORR activity without introducing catalyst degradation, an investigation of measurement protocols for ECA and ORR activity was conducted. Down-selected protocols were based on the criteria of reproducibility, duration of experiments, impurity effects and magnitude of pseudo-capacitive background correction. In sum, statistical reproducibility of ORR activity for poly-Pt and Pt supported on high surface area carbon was demonstrated.« less

Oak Ridge Reservation Bird Records and Population Trends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, W. K.; Giffen, N. R.; Wade, M. C.

Bird data have been collected through surveys, environmental assessments, and other observations for decades in the Oak Ridge National Environmental Research Park, located on the US Department of Energy’s Oak Ridge Reservation (ORR) in East Tennessee. Birds were recorded in a variety of habitats, including wetlands, interior forests, grasslands, ponds, corridors, forest edges, and more. Most of the information was gathered from waterfowl surveys conducted from 1990 to 2008, from Partners in Flight (PIF) breeding bird surveys conducted from 1995 to 2013, and from past publications and research on Reservation birds. We have also included our own observations and, inmore » a few instances, credible observations of ORR birds of which we have been made aware through eBird or discussions with area ornithologists and bird watchers. For the period 1950-2014, we were able to document 228 species of birds on the ORR. Several of these species are known from historic records only, while others were not known to have ever occurred on the Reservation until recently. This report does not include PIF breeding bird data from the 2014 season or any records after July 2014. Twenty-two species--approximately 10% of the total number of species observed--have state-listed status in Tennessee as endangered, threatened, or in need of management. Of the 228 species we documented, 120 are believed to be breeding birds on the ORR.« less

Oak Ridge Reservation Bird Records and Population Trends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, W. Kelly; Giffen, Neil R.; Wade, Murray

Bird data have been collected through surveys, environmental assessments, and other observations for decades in the Oak Ridge National Environmental Research Park, located on the US Department of Energy s Oak Ridge Reservation (ORR) in East Tennessee. Birds were recorded in a variety of habitats, including wetlands, interior forests, grasslands, ponds, corridors, forest edges, and more. Most of the information was gathered from waterfowl surveys conducted from 1990 to 2008, from Partners in Flight (PIF) breeding bird surveys conducted from 1995 to 2013, and from past publications and research on Reservation birds. We have also included our own observations and,more » in a few instances, credible observations of ORR birds of which we have been made aware through eBird or discussions with area ornithologists and bird watchers. For the period 1950 2014, we were able to document 228 species of birds on the ORR. Several of these species are known from historic records only, while others were not known to have ever occurred on the Reservation until recently. This report does not include PIF breeding bird data from the 2014 season or any records after July 2014. Twenty-two species approximately 10% of the total number of species observed have state-listed status in Tennessee as endangered, threatened, or in need of management. Of the 228 species we documented, 120 are believed to be breeding birds on the ORR.« less

Clinical value of circulating endothelial cell levels in metastatic colorectal cancer patients treated with first-line chemotherapy and bevacizumab.

PubMed

Malka, D; Boige, V; Jacques, N; Vimond, N; Adenis, A; Boucher, E; Pierga, J Y; Conroy, T; Chauffert, B; François, E; Guichard, P; Galais, M P; Cvitkovic, F; Ducreux, M; Farace, F

2012-04-01

We investigated whether circulating endothelial cells (CECs) predict clinical outcome of first-line chemotherapy and bevacizumab in metastatic colorectal cancer (mCRC) patients. In a substudy of the randomized phase II FNCLCC ACCORD 13/0503 trial, CECs (CD45- CD31+ CD146+ 7-amino-actinomycin- cells) were enumerated in 99 patients by four-color flow cytometry at baseline and after one cycle of treatment. We correlated CEC levels with objective response rate (ORR), 6-month progression-free survival (PFS) rate (primary end point of the trial), PFS, and overall survival (OS). Multivariate analyses of potential prognostic factors, including CEC counts and Köhne score, were carried out. By multivariate analysis, high baseline CEC levels were the only independent prognostic factor for 6-month PFS rate (P < 0.01) and were independently associated with worse PFS (P = 0.02). High CEC levels after one cycle were the only independent prognostic factor for ORR (P = 0.03). High CEC levels at both time points independently predicted worse ORR (P = 0.025), 6-month PFS rate (P = 0.007), and PFS (P = 0.02). Köhne score was the only variable associated with OS. CEC levels at baseline and after one treatment cycle may independently predict ORR and PFS in mCRC patients starting first-line bevacizumab and chemotherapy.

Electrocatalytic performances of LaNi1-xMgxO3 perovskite oxides as bi-functional catalysts for lithium air batteries

NASA Astrophysics Data System (ADS)

Du, Zhenzhen; Yang, Peng; Wang, Long; Lu, Yuhao; Goodenough, J. B.; Zhang, Jian; Zhang, Dawei

2014-11-01

Mg-doped perovskite oxides LaNi1-xMgxO3 (x = 0, 0.08, 0.15) electrocatalysts are synthesized by a sol-gel method using citric acid as complex agent and ethylene glycol as thickening agent. The intrinsic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity of as-prepared perovskite oxides in aqueous electrolyte are examined on a rotating disk electrode (RDE) set up. Li-air primary batteries on the basis of Mg-doped perovskite oxides LaNi1-xMgxO3 (x = 0, 0.08, 0.15) and nonaqueous electrolyte are also fabricated and tested. In terms of the ORR current densities and OER current densities, the performance is enhanced in the order of LaNiO3, LaNi0.92Mg0.08O3 and LaNi0.85Mg0.15O3. Most notably, partially substituting nickel with magnesium suppresses formation of Ni2+ and ensures high concentration of both OER and ORR reaction energy favorable Ni3+ (eg = 1) on the surface of perovskite catalysts. Nonaqueous Li-air primary battery using LaNi0.92Mg0.08O3 and LaNi0.85Mg0.15O3 as the cathode catalysts exhibit improved performances compared with LaNiO3 catalyst, which are consistent with the ORR current densities.

Enhanced electrocatalytic activity of PANI and CoFe2O4/PANI composite supported on graphene for fuel cell applications

NASA Astrophysics Data System (ADS)

Mohanraju, Karuppannan; Sreejith, Vasudevan; Ananth, Ramaiyan; Cindrella, Louis

2015-06-01

New catalysts of reduced graphene oxide (rGO) with poly aniline (PANI) and cobalt ferrite (CF) have been successfully prepared by simple chemical reduction method. Their electrocatalytic activity for oxygen reduction reaction (ORR) was evaluated. Semi-crystalline nature of CF was analyzed by X-ray diffraction (XRD) study. Surface morphology by HR-SEM showed features of CF particles and PANI film on graphene sheets. FT-IR studies revealed changes in C-N and Cdbnd N stretching vibrations of PANI confirming bonding of PANI to graphene sheets. Raman spectrum showed presence of PANI on distorted graphene layers. TG/DTA revealed thermal stability and extent of loading of CF in composite. ORR performance was studied using catalyst modified rotating disc electrode (RDE). A maximum kinetic current density of -3.46 mA cm-2 at -0.2 V was obtained for CF/PANI/rGO. Tafel slope, onset and half wave potentials for the catalyst were obtained from ORR response. Durability studies showed that synthesized electrocatalyst has better stability and methanol tolerance than commercial Pt/C catalyst. To the best of our knowledge, this is the first study aiming enhancement of ORR activity using PANI and CoFe2O4 on graphene support. A trace amount of Pt in the composite boosted the performance of single PEM fuel cell.

Facile preparation of efficient electrocatalysts for oxygen reduction reaction: One-dimensional meso/macroporous cobalt and nitrogen Co-doped carbon nanofibers

NASA Astrophysics Data System (ADS)

Yoon, Ki Ro; Choi, Jinho; Cho, Su-Ho; Jung, Ji-Won; Kim, Chanhoon; Cheong, Jun Young; Kim, Il-Doo

2018-03-01

Efficient electrocatalyst for oxygen reduction reaction (ORR) is an essential component for stable operation of various sustainable energy conversion and storage systems such as fuel cells and metal-air batteries. Herein, we report a facile preparation of meso/macroporous Co and N co-doped carbon nanofibers (Co-Nx@CNFs) as a high performance and cost-effective electrocatalyst toward ORR. Co-Nx@CNFs are simply obtained from electrospinning of Co precursor and bicomponent polymers (PVP/PAN) followed by temperature controlled carbonization and further activation step. The prepared Co-Nx@CNF catalyst carbonized at 700 °C (Co-Nx@CNF700) shows outstanding ORR performance, i.e., a low onset potential (0.941 V) and half wave potential (0.814 V) with almost four-electron transfer pathways (n= 3.9). In addition, Co-Nx@CNF700 exhibits a superior methanol tolerance and higher stability (>70 h) in Zn-air battery in comparison with Pt/C catalyst (∼30 h). The outstanding performance of Co-Nx@CNF700 catalysts is attributed to i) enlarged surface area with bimodal porosity achieved by leaching of inactive species, ii) increase of exposed ORR active Co-Nx moieties and graphitic edge sites, and iii) enhanced electrical conductivity and corrosion resistance due to the existence of numerous graphitic flakes in carbon matrix.

Green Synthesis of Three-Dimensional Hybrid N-Doped ORR Electro-Catalysts Derived from Apricot Sap

PubMed Central

Karunagaran, Ramesh; Coghlan, Campbell; Gulati, Karan; Tung, Tran Thanh; Doonan, Christian

2018-01-01

Rapid depletion of fossil fuel and increased energy demand has initiated a need for an alternative energy source to cater for the growing energy demand. Fuel cells are an enabling technology for the conversion of sustainable energy carriers (e.g., renewable hydrogen or bio-gas) into electrical power and heat. However, the hazardous raw materials and complicated experimental procedures used to produce electro-catalysts for the oxygen reduction reaction (ORR) in fuel cells has been a concern for the effective implementation of these catalysts. Therefore, environmentally friendly and low-cost oxygen reduction electro-catalysts synthesised from natural products are considered as an attractive alternative to currently used synthetic materials involving hazardous chemicals and waste. Herein, we describe a unique integrated oxygen reduction three-dimensional composite catalyst containing both nitrogen-doped carbon fibers (N-CF) and carbon microspheres (N-CMS) synthesised from apricot sap from an apricot tree. The synthesis was carried out via three-step process, including apricot sap resin preparation, hydrothermal treatment, and pyrolysis with a nitrogen precursor. The nitrogen-doped electro-catalysts synthesised were characterised by SEM, TEM, XRD, Raman, and BET techniques followed by electro-chemical testing for ORR catalysis activity. The obtained catalyst material shows high catalytic activity for ORR in the basic medium by facilitating the reaction via a four-electron transfer mechanism. PMID:29382103

Microbial fuel cells with highly active aerobic biocathodes

NASA Astrophysics Data System (ADS)

Milner, Edward M.; Popescu, Dorin; Curtis, Tom; Head, Ian M.; Scott, Keith; Yu, Eileen H.

2016-08-01

Microbial fuel cells (MFCs), which convert organic waste to electricity, could be used to make the wastewater infrastructure more energy efficient and sustainable. However, platinum and other non-platinum chemical catalysts used for the oxygen reduction reaction (ORR) at the cathode of MFCs are unsustainable due to their high cost and long-term degradation. Aerobic biocathodes, which use microorganisms as the biocatalysts for cathode ORR, are a good alternative to chemical catalysts. In the current work, high-performing aerobic biocathodes with an onset potential for the ORR of +0.4 V vs. Ag/AgCl were enriched from activated sludge in electrochemical half-cells poised at -0.1 and + 0.2 V vs. Ag/AgCl. Gammaproteobacteria, distantly related to any known cultivated gammaproteobacterial lineage, were identified as dominant in these working electrode biofilms (23.3-44.3% of reads in 16S rRNA gene Ion Torrent libraries), and were in very low abundance in non-polarised control working electrode biofilms (0.5-0.7%). These Gammaproteobacteria were therefore most likely responsible for the high activity of biologically catalysed ORR. In MFC tests, a high-performing aerobic biocathode increased peak power 9-fold from 7 to 62 μW cm-2 in comparison to an unmodified carbon cathode, which was similar to peak power with a platinum-doped cathode at 70 μW cm-2.

Hollow-spherical Co/N-C nanoparticle as an efficient electrocatalyst used in air cathode microbial fuel cell.

PubMed

Yang, Tingting; Li, Kexun; Pu, Liangtao; Liu, Ziqi; Ge, Baochao; Pan, Yajun; Liu, Ying

2016-12-15

The hollow-spherical Co/N-C nanoparticle, which is synthesized via a simple hydrothermal reaction followed by heat treatment, is firstly used as electrocatalyst for oxygen reduction reaction (ORR) in air-cathode microbial fuel cell (MFC). The maximum power density of MFC with 10% Co/N-C air-cathode is as high as 2514±59mWm(-2), which is almost 174% higher than the control. The exchange current density (i0) of cathode equipped with 10% Co/N-C is 238% higher than that of untreated AC. While the total resistance of treated samples decreases from 13.017 to 10.255Ω. The intensity ratio of Raman D to G band (ID/IG) decreases from 0.93 (N-C) to 0.73 (Co/N-C), indicating the catalyst forms graphite structure. Both XRD and XPS testify that Co is bonded to N within graphitic sheets and serves as the active sites in ORR. The four-electron pathway of the Co/N-C also plays a crucial role in electrochemical catalytic activity. As a result, it can be expected that the as-synthesized Co/N-C, with extraordinary electro-catalytic performance towards ORR, will be a promising alternative to the state-of-the-art non-precious metal ORR electro-catalysts for electrochemical energy applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Green Synthesis of Three-Dimensional Hybrid N-Doped ORR Electro-Catalysts Derived from Apricot Sap.

PubMed

Karunagaran, Ramesh; Coghlan, Campbell; Shearer, Cameron; Tran, Diana; Gulati, Karan; Tung, Tran Thanh; Doonan, Christian; Losic, Dusan

2018-01-28

Rapid depletion of fossil fuel and increased energy demand has initiated a need for an alternative energy source to cater for the growing energy demand. Fuel cells are an enabling technology for the conversion of sustainable energy carriers (e.g., renewable hydrogen or bio-gas) into electrical power and heat. However, the hazardous raw materials and complicated experimental procedures used to produce electro-catalysts for the oxygen reduction reaction (ORR) in fuel cells has been a concern for the effective implementation of these catalysts. Therefore, environmentally friendly and low-cost oxygen reduction electro-catalysts synthesised from natural products are considered as an attractive alternative to currently used synthetic materials involving hazardous chemicals and waste. Herein, we describe a unique integrated oxygen reduction three-dimensional composite catalyst containing both nitrogen-doped carbon fibers (N-CF) and carbon microspheres (N-CMS) synthesised from apricot sap from an apricot tree. The synthesis was carried out via three-step process, including apricot sap resin preparation, hydrothermal treatment, and pyrolysis with a nitrogen precursor. The nitrogen-doped electro-catalysts synthesised were characterised by SEM, TEM, XRD, Raman, and BET techniques followed by electro-chemical testing for ORR catalysis activity. The obtained catalyst material shows high catalytic activity for ORR in the basic medium by facilitating the reaction via a four-electron transfer mechanism.

Roles of Mo Surface Dopants in Enhancing the ORR Performance of Octahedral PtNi Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Qingying; Zhao, Zipeng; Cao, Liang

Doping with a transition metal was recently shown to greatly boost the activity and durability of PtNi/C octahedral nanoparticles (NPs) for the oxygen reduction reaction (ORR), but its specific roles remain unclear. By combining electrochemistry, ex situ and in situ spectroscopic techniques, density functional theory calculations, and a newly developed kinetic Monte Carlo model, we showed that Mo atoms are preferentially located on the vertex and edge sites of Mo–PtNi/C in the form of oxides, which are stable within the wide potential window of the electrochemical cycle. These surface Mo oxides stabilize adjacent Pt sites, hereby stabilizing the octahedral shapemore » enriched with (111) facets, and lead to increased concentration of Ni in subsurface layers where they are protected against acid dissolution. Consequently, the favorable Pt 3Ni(111) structure for the ORR is stabilized on the surface of PtNi/C NPs in acid against voltage cycling. Significantly, the unusual potential-dependent oxygen coverage trend on Mo-doped PtNi/C NPs as revealed by the surface-sensitive Δμ analysis suggests that the Mo dopants may also improve the ORR kinetics by modifying the coordination environments of Pt atoms on the surface. Lastly, our studies point out a possible way to stabilize the favorable shape and composition established on conceptual catalytic models in practical nanoscale catalysts.« less

A method for the evaluation of image quality according to the recognition effectiveness of objects in the optical remote sensing image using machine learning algorithm.

PubMed

Yuan, Tao; Zheng, Xinqi; Hu, Xuan; Zhou, Wei; Wang, Wei

2014-01-01

Objective and effective image quality assessment (IQA) is directly related to the application of optical remote sensing images (ORSI). In this study, a new IQA method of standardizing the target object recognition rate (ORR) is presented to reflect quality. First, several quality degradation treatments with high-resolution ORSIs are implemented to model the ORSIs obtained in different imaging conditions; then, a machine learning algorithm is adopted for recognition experiments on a chosen target object to obtain ORRs; finally, a comparison with commonly used IQA indicators was performed to reveal their applicability and limitations. The results showed that the ORR of the original ORSI was calculated to be up to 81.95%, whereas the ORR ratios of the quality-degraded images to the original images were 65.52%, 64.58%, 71.21%, and 73.11%. The results show that these data can more accurately reflect the advantages and disadvantages of different images in object identification and information extraction when compared with conventional digital image assessment indexes. By recognizing the difference in image quality from the application effect perspective, using a machine learning algorithm to extract regional gray scale features of typical objects in the image for analysis, and quantitatively assessing quality of ORSI according to the difference, this method provides a new approach for objective ORSI assessment.

Liquid Fuels: Pyrolytic Degradation and Fire Spread Behavior as Influenced by Buoyancy

NASA Technical Reports Server (NTRS)

Ross, Howard D. (Technical Monitor); Yeboah, Yaw D.

2003-01-01

This project was conducted by the Combustion and Emission Control Lab in the Engineering Department at Clark Atlanta University under NASA Grant No. NCC3-707. The work aimed at providing data to supplement the ongoing NASA research activities on flame spread across liquid pools by providing flow visualization and velocity measurements especially in the gas phase and gas-liquid interface. During this investigation, the detailed physics of flame spread across liquid pools was revealed using particle image velocimetry (PIV), 3-dimensional Laser Doppler velocimetry (LDV) and high-speed video imaging system (HSVS). Flow fields (front and side views) of both the liquid and gas phases were visually investigated for the three subflash regimes of flame spread behavior. Some interesting findings obtained from the front and side views on flame spread across butanol pools are presented. PIV results showed the size of the transient vortex in the liquid phase near the flame front varied with the initial pool temperature. The transient vortex ahead of the flame front in the gas phase was, for the first time, clearly observed located just within 0-3 mm above the liquid surface and its size was dependent on the initial pool temperature. We calculated the flow velocity at 1 mm below the liquid surface near the flame front and inferred the generation mechanism of the vortex in the gas phase. Finally, after comparison of the flow velocity of the liquid surface and the flame spread rate, a reasonable explanation to the formation mechanism of the pulsating characteristic was proposed. This explanation is compatible with the previous numerical calculations and deductions.

Metallated porphyrin based porous organic polymers as efficient electrocatalysts

NASA Astrophysics Data System (ADS)

Lu, Guolong; Zhu, Youlong; Xu, Kongliang; Jin, Yinghua; Ren, Zhiyong Jason; Liu, Zhenning; Zhang, Wei

2015-10-01

Developing efficient, stable and low-cost catalysts for Oxygen Reduction Reaction (ORR) is of great significance to many emerging technologies including fuel cells and metal-air batteries. Herein, we report the development of a cobalt(ii) porphyrin based porous organic polymer (CoPOP) and its pyrolyzed derivatives as highly active ORR catalysts. The as-synthesized CoPOP exhibits high porosity and excellent catalytic performance stability, retaining ~100% constant ORR current over 50 000 s in both alkaline and acidic media. Pyrolysis of CoPOP at various temperatures (600 °C, 800 °C, and 1000 °C) yields the materials consisting of graphitic carbon layers and cobalt nanoparticles, which show greatly enhanced catalytic activity compared to the as-synthesized CoPOP. Among them, CoPOP-800/C pyrolyzed at 800 °C shows the highest specific surface area and ORR activity, displaying the most positive half-wave potential (0.825 V vs. RHE) and the largest limited diffusion current density (5.35 mA cm-2) in an alkaline medium, which are comparable to those of commercial Pt/C (20 wt%) (half-wave potential 0.829 V vs. RHE, limited diffusion current density 5.10 mA cm-2). RDE and RRDE experiments indicate that CoPOP-800/C directly reduces molecular oxygen to water through a 4-e- pathway in both alkaline and acidic media. More importantly, CoPOP-800/C exhibits excellent durability and methanol-tolerance under acidic and alkaline conditions, which surpass the Pt/C (20 wt%) system.Developing efficient, stable and low-cost catalysts for Oxygen Reduction Reaction (ORR) is of great significance to many emerging technologies including fuel cells and metal-air batteries. Herein, we report the development of a cobalt(ii) porphyrin based porous organic polymer (CoPOP) and its pyrolyzed derivatives as highly active ORR catalysts. The as-synthesized CoPOP exhibits high porosity and excellent catalytic performance stability, retaining ~100% constant ORR current over 50 000 s in both alkaline and acidic media. Pyrolysis of CoPOP at various temperatures (600 °C, 800 °C, and 1000 °C) yields the materials consisting of graphitic carbon layers and cobalt nanoparticles, which show greatly enhanced catalytic activity compared to the as-synthesized CoPOP. Among them, CoPOP-800/C pyrolyzed at 800 °C shows the highest specific surface area and ORR activity, displaying the most positive half-wave potential (0.825 V vs. RHE) and the largest limited diffusion current density (5.35 mA cm-2) in an alkaline medium, which are comparable to those of commercial Pt/C (20 wt%) (half-wave potential 0.829 V vs. RHE, limited diffusion current density 5.10 mA cm-2). RDE and RRDE experiments indicate that CoPOP-800/C directly reduces molecular oxygen to water through a 4-e- pathway in both alkaline and acidic media. More importantly, CoPOP-800/C exhibits excellent durability and methanol-tolerance under acidic and alkaline conditions, which surpass the Pt/C (20 wt%) system. Electronic supplementary information (ESI) available: Details of the experimental section, powder X-ray diffraction (PXRD) data, scanning electron microscopy (FE-SEM) images, Fourier transform infrared spectroscopy (FT-IR) data, and additional electrochemical data. See DOI: 10.1039/c5nr05324b

Effects of age and sex ratios on offspring recruitment rates in translocated black rhinoceros.

PubMed

Gedir, Jay V; Law, Peter R; du Preez, Pierre; Linklater, Wayne L

2018-06-01

Success of animal translocations depends on improving postrelease demographic rates toward establishment and subsequent growth of released populations. Short-term metrics for evaluating translocation success and its drivers, like postrelease survival and fecundity, are unlikely to represent longer-term outcomes. We used information theory to investigate 25 years of data on black rhinoceros (Diceros bicornis) translocations. We used the offspring recruitment rate (ORR) of translocated females-a metric integrating survival, fecundity, and offspring recruitment at sexual maturity-to detect determinants of success. Our unambiguously best model (AICω = 0.986) predicted that ORR increases with female age at release as a function of lower postrelease adult rhinoceros sex ratio (males:females). Delay of first postrelease reproduction and failure of some females to recruit any calves to sexual maturity most influenced the pattern of ORRs, and the leading causes of recruitment failure were postrelease female death (23% of all females) and failure to calve (24% of surviving females). We recommend translocating older females (≥6 years old) because they do not exhibit the reproductive delay and low ORRs of juveniles (<4 years old) or the higher rates of recruitment failure of juveniles and young adults (4-5.9 years old). Where translocation of juveniles is necessary, they should be released into female-biased populations, where they have higher ORRs. Our study offers the unique advantage of a long-term analysis across a large number of replicate populations-a science-by-management experiment as a proxy for a manipulative experiment, and a rare opportunity, particularly for a large, critically endangered taxon such as the black rhinoceros. Our findings differ from previous recommendations, reinforce the importance of long-term data sets and comprehensive metrics of translocation success, and suggest attention be shifted from ecological to social constraints on population growth and species recovery, particularly when translocating species with polygynous breeding systems. © 2017 Society for Conservation Biology.

Oak Ridge Reservation Annual Site Environmental Report, 2003

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, JF

2004-08-24

This document is prepared annually to summarize environmental activities, primarily environmental-monitoring activities, on the ORR and within the ORR surroundings. The document fulfills the requirement of U.S. Department of Energy (DOE) Order 231.1, ''Environment, Safety and Health Reporting,'' for an annual summary of environmental data to characterize environmental performance. The environmental monitoring criteria are described in DOE Order 450.1, ''Environmental Protection Program''. The results summarized in this report are based on data collected prior to and through 2003. This report is not intended to provide the results of all sampling on the ORR. Additional data collected for other site andmore » regulatory purposes, such as environmental restoration remedial investigation reports, waste management characterization sampling data, and environmental permit compliance data, are presented in other documents that have been prepared in accordance with applicable DOE guidance and/or laws. Corrections to the report for the previous year are found in Appendix A. Environmental monitoring on the ORR consists primarily of two major activities: effluent monitoring and environmental surveillance. Effluent monitoring involves the collection and analysis of samples or measurements of liquid and gaseous effluents at the point of release to the environment; these measurements allow the quantification and official reporting of contaminants, assessment of radiation and chemical exposures to the public, and demonstration of compliance with applicable standards and permit requirements. Environmental surveillance consists of the collection and analysis of environmental samples from the site and its environs; these activities provide direct measurement of contaminants in air, water, groundwater, soil, foods, biota, and other media subsequent to effluent release into the environment. Environmental surveillance data provide information regarding conformity with applicable DOE orders and, combined with data from effluent monitoring, allow the determination of chemical and radiation dose/exposure assessments of ORR operations and effects, if any, on the local environment.« less

Oak Ridge Reservation Annual Site Environmental Report for 2006

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMahon, Wayne; Hughes, Joan; Coffey, Mike

2007-09-01

This document is prepared annually to summarize environmental activities, primarily environmental-monitoring activities, on the Oak Ridge Reservation (ORR) and within the ORR surroundings. The document fulfills the requirement of Department of Energy (DOE) Order 23l.IA, 'Environment, Safety and Health Reporting,' for an annual summary of environmental data to characterize environmental performance. The environmental-monitoring criteria are described in DOE Order 450.1, 'Environmental Protection Program.' The results summarized in this report are based on data collected prior to and through 2006. This report is not intended to provide the results of all sampling on the ORR. Additional data collected for other sitemore » and regulatory purposes, such as environmental restoration remedial investigation reports, waste management characterization sampling data, and environmental permit compliance data, are presented in other documents that have been prepared in accordance with applicable DOE guidance and/or laws and are referenced herein as appropriate. Corrections to the report for the previous year are found in Appendix A. Environmental monitoring on the ORR consists primarily of two major activities: effluent monitoring and environmental surveillance. Effluent monitoring involves the collection and analysis of samples or measurements of liquid and gaseous effluents at the point of release to the environment; these measurements allow the quantification and official reporting of contaminants, assessment of radiation and chemical exposures to the public, and demonstration of compliance with applicable standards and permit requirements. Environmental surveillance consists of the collection and analysis of environmental samples from the site and its environs; these activities provide direct measurement of contaminant concentrations in air, water, groundwater, soil, foods, biota, and other media. Environmental surveillance data provide information regarding conformity with applicable DOE orders and, combined with data from effluent monitoring, allow the determination of chemical and radiation dose/exposure assess ments of ORR operations and effects, if any, on the local environment.« less

Oak Ridge Reservation Annual Site Environmental Report for 2003

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2004-09-30

This document is prepared annually to summarize environmental activities, primarily environmental-monitoring activities, on the ORR and within the ORR surroundings. The document fulfills the requirement of U.S. Department of Energy (DOE) Order 231.1, “Environment, Safety and Health Reporting,” for an annual summary of environmental data to characterize environmental performance. The environmental monitoring criteria are described in DOE Order 450.1, “Environmental Protection Program.” The results summarized in this report are based on data collected prior to and through 2003. This report is not intended to provide the results of all sampling on the ORR. Additional data collected for other site andmore » regulatory purposes, such as environmental restoration remedial investigation reports, waste management characterization sampling data, and environmental permit compliance data, are presented in other documents that have been prepared in accordance with applicable DOE guidance and/or laws. Corrections to the report for the previous year are found in Appendix A. Environmental monitoring on the ORR consists primarily of two major activities: effluent monitoring and environmental surveillance. Effluent monitoring involves the collection and analysis of samples or measurements of liquid and gaseous effluents at the point of release to the environment; these measurements allow the quantification and official reporting of contaminants, assessment of radiation and chemical exposures to the public, and demonstration of compliance with applicable standards and permit requirements. Environmental surveillance consists of the collection and analysis of environmental samples from the site and its environs; these activities provide direct measurement of contaminants in air, water, groundwater, soil, foods, biota, and other media subsequent to effluent release into the environment. Environmental surveillance data provide information regarding conformity with applicable DOE orders and, combined with data from effluent monitoring, allow the determination of chemical and radiation dose/exposure assessments of ORR operations and effects, if any, on the local environment.« less

Oak Ridge Reservation annual site environmental report for 2008

DOE Office of Scientific and Technical Information (OSTI.GOV)

none,

2009-09-01

The Oak Ridge Reservation (ORR) consists of three major government-owned, contractor-operated facilities: the Y-12 National Security Complex, Oak Ridge National Laboratory, and East Tennessee Technology Park. The ORR was established in the early 1940s as part of the Manhattan Project, a secret undertaking that produced materials for the first atomic bombs. The reservation’s role has evolved over the years, and it continues to adapt to meet the changing defense, energy, and research needs of the United States. Both the work carried out for the war effort and subsequent research, development, and production activities have involved, and continue to involve, themore » use of radiological and hazardous materials. The Oak Ridge Reservation Annual Site Environmental Report and supporting data are available at http://www.ornl.gov/sci/env_rpt or from the project director. This document is prepared annually to summarize environmental activities, primarily environmental monitoring activities, on the Oak Ridge Reservation (ORR) and within the ORR surroundings. The document fulfills the requirement of Department of Energy (DOE) Order 231.1A, Environment, Safety and Health Reporting, for an annual summary of environmental data to characterize environmental performance. The environmental monitoring criteria are described in DOE Order 450.1A, Environmental Protection Program. The results summarized in this report are based on data collected prior to and through 2008. This report is not intended to provide the results of all sampling on the ORR. Additional data collected for other site and regulatory purposes, such as environmental restoration/remedial investigation reports, waste management characterization sampling data, and environmental permit compliance data, are presented in other documents that have been prepared in accordance with applicable DOE guidance and/or laws and are referenced herein as appropriate. Corrections to the report for the previous year are found in Appendix A. Appendix B contains a glossary of technical terms that may be useful for clarifying some of the language used in this document.« less

3D Nitrogen, Sulfur-Codoped Carbon Nanomaterial-Supported Cobalt Oxides with Polyhedron-Like Particles Grafted onto Graphene Layers as Highly Active Bicatalysts for Oxygen-Evolving Reactions.

PubMed

Huang, Xiaobo; Wang, Jianqiang; Bao, Hongliang; Zhang, Xiangkun; Huang, Yongmin

2018-02-28

The extensive research and developments of highly efficient oxygen electrode electrocatalysts to get rid of the kinetic barriers for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are very important in energy conversion and storage devices. Especially, exploring nonprecious metal alternatives to replace traditional noble metal catalysts with high cost and poor durability is the paramount mission. In this paper, we utilize property-flexible ZIF-67 and sulfur-functionalized graphene oxide to obtain a cobalt, nitrogen, and sulfur codoped nanomaterial with 3D hierarchical porous structures, owing to their rich dopant species and good conductivity. The crosslinked structures of polyhedron particles throughout the whole carbon framework speeds up the mass transportation and charge-delivery processes during oxygen-evolving reactions. Also, by exploring the location and coordination type of sulfur dopants, we emphasize the effects of sulfone and sulfide functional groups anchored into the graphitic structure on enhancing the catalytic abilities for ORR and OER. To note, compared to the noble metal electrocatalysts, the best-performing CoO@Co 3 O 4 /NSG-650 (0.79 V) is 40 mV less active than the commercial Pt/C catalyst (0.83 V) for ORR and merely 10 mV behind IrO 2 (1.68 V) for OER. Besides, the metric between ORR and OER difference for CoO@Co 3 O 4 /NSG-650 to evaluate its overall electrocatalytic activity is 0.90 V, surpassing 290 and 430 mV over Pt/C (1.19 V) and IrO 2 (1.33 V). Comprehensively, the as-prepared CoO@Co 3 O 4 /NSG-650 indicates excellent bifunctional catalytic activities for ORR and OER, which shows great potential for replacing noble metal catalysts in the application of fuel cells and metal-air batteries.

Side differences in cerebrovascular accidents after cardiac surgery: a statistical analysis of neurologic symptoms and possible implications for anatomic mechanisms of aortic particle embolization.

PubMed

Boivie, Patrik; Edström, Cecilia; Engström, Karl Gunnar

2005-03-01

Aortic manipulation and particle embolization have been identified to cause cerebrovascular accidents in cardiac surgery. Recent data suggest that left-hemispheric cerebrovascular accident (right-sided symptoms) is more common, and this has been interpreted as being caused by aortic cannula stream jets. Our aim was to evaluate symptoms of cerebrovascular accident and side differences from a retrospective statistical analysis. During a 2-year period, 2641 consecutive cardiac surgery cases were analyzed. Patients positive for cerebrovascular accident were extracted from a database designed to monitor clinical symptoms. A protocol was used to confirm symptom data with the correct diagnosis in patient records. Patients were subdivided into 3 groups: control, immediate cerebrovascular accident, and delayed cerebrovascular accident. Among pooled patients, immediate and delayed cerebrovascular accidents were 3.0% and 0.9%, respectively. The expected predisposing factors behind immediate cerebrovascular accidents were significant, although the type of operation affected this search. Aortic quality was a strong predictor ( P < .001). The rate of delayed cerebrovascular accident was unaffected by surgery group. Left-sided symptoms of immediate cerebrovascular accident were approximately twice as frequent ( P = .016) as on the contralateral side. This phenomenon was observed for pooled patients and for isolated coronary bypass procedures (n = 1882; P = .025). Immediate cerebrovascular accident and aortic calcifications are linked. The predominance of left-sided symptoms may suggest that aortic manipulation and anatomic mechanisms in the aortic arch are more likely to cause cerebrovascular accidents than effects from cannula stream jets.

The US National Transonic Facility, NTF

NASA Technical Reports Server (NTRS)

Bruce, Walter E., Jr.; Gloss, Blair B.

1989-01-01

The construction of the National Transonic Facility was completed in September 1982 and the start-up and checkout of tunnel systems were performed over the next two years. In August 1984, the Operational Readiness Review (ORR) was conducted and the facility was declared operational for final checkout of cryogenic instrumentation and control systems, and for the aerodynamic calibration and testing to commence. Also, the model access system for the cryogenic mode of operation would be placed into operation along with tunnel testing. Since the ORR, a host of operating problems resulting from the cryogenic environment were identified and solved. These range from making mechanical and electrical systems functional to eliminating temperature induced model vibration to coping with the outgassing of moisture from the thermal insulation. Additionally, a series of aerodynamic tests have demonstrated data quality and provided research data on several configurations. Some of the more significant efforts are reviewed since the ORR and the NTF status concerning hardware, instrumentation and process controls systems, operating constraints imposed by the cryogenic environment, and data quality are summarized.

An overview of safety assessment, regulation, and control of hazardous material use at NREL

NASA Astrophysics Data System (ADS)

Nelson, B. P.; Crandall, R. S.; Moskowitz, P. D.; Fthenakis, V. M.

1992-12-01

This paper summarizes the methodology we use to ensure the safe use of hazardous materials at the National Renewable Energy Laboratory (NREL). First, we analyze the processes and the materials used in those processes to identify the hazards presented. Then we study federal, state, and local regulations and apply the relevant requirements to our operations. When necessary, we generate internal safety documents to consolidate this information. We design research operations and support systems to conform to these requirements. Before we construct the systems, we perform a semiquantitative risk analysis on likely accident scenarios. All scenarios presenting an unacceptable risk require system or procedural modifications to reduce the risk. Following these modifications, we repeat the risk analysis to ensure that the respective accident scenarios present an acceptable risk. Once all risks are acceptable, we conduct an operational readiness review (ORR). A management-appointed panel performs the ORR ensuring compliance with all relevant requirements. After successful completion of the ORR, operations can begin.

Hollow structured carbon-supported nickel cobaltite nanoparticles as an efficient bifunctional electrocatalyst for the oxygen reduction and evolution reaction

DOE PAGES

Wang, Jie; Han, Lili; Lin, Ruoqian; ...

2016-01-05

Here, the exploration of efficient electrocatalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is essential for fuel cells and metal-air batteries. In this study, we developed 3D hollow-structured NiCo 2O 4/C nanoparticles with interconnected pores as bifunctional electrocatalysts, which are transformed from solid NiCo 2 alloy nanoparticles through the Kirkendall effect. The unique hollow structure of NiCo 2O 4 nanoparticles increases the number of active sites and improves contact with the electrolyte to result in excellent ORR and OER performances. In addition, the hollow-structured NiCo 2O 4/C nanoparticles exhibit superior long-term stability for both themore » ORR and OER compared to commercial Pt/C. The template- and surfactant-free synthetic strategy could be used for the low-cost and large-scale synthesis of hollow-structured materials, which would facilitate the screening of high-efficiency catalysts for energy conversion.« less

Label-free imaging and spectroscopy for early detection of cervical cancer.

PubMed

Jing, Yueyue; Wang, Yulan; Wang, Xinyi; Song, Chuan; Ma, Jiong; Xie, Yonghui; Fei, Yiyan; Zhang, Qinghua; Mi, Lan

2018-05-01

The label-free imaging and spectroscopy method was studied on cervical unstained tissue sections obtained from 36 patients. The native fluorescence spectra of tissues are analyzed by the optical redox ratio (ORR), which is defined as fluorescence intensity ratio between NADH and FAD, and indicates the metabolism change with the cancer development. The ORRs of normal tissues are consistently higher than those of precancer or cancerous tissues. A criterion line of ORR at 5.0 can be used to discriminate cervical precancer/cancer from normal tissues. The sensitivity and specificity of the native fluorescence spectroscopy method for cervical cancer diagnosis are determined as 100% and 91%. Moreover, the native fluorescence spectroscopy study is much more sensitive on the healthy region of cervical precancer/cancer patients compared with the traditional clinical staining method. The results suggest label-free imaging and spectroscopy is a fast, highly sensitive and specific method on the detection of cervical cancer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reduced-graphene-oxide supported tantalum-based electrocatalysts: Controlled nitrogen doping and oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Yang, Xiaoyun; Mo, Qijie; Guo, Yulin; Chen, Nana; Gao, Qingsheng

2018-03-01

Controlled N-doping is feasible to engineer the surface stoichiometry and the electronic configuration of metal-oxide electrocatalysts toward efficient oxygen reduction reactions (ORR). Taking reduced graphene oxide supported tantalum-oxides (TaOx/RGO) for example, this work illustrated the controlled N-doping in both metal-oxides and carbon supports, and the contribution to the improved ORR activity. The active N-doped TaOx/RGO electrocatalysts were fabricated via SiO2-assisted pyrolysis, in which the amount and kind of N-doping were tailored toward efficient electrocatalysis. The optimal nanocomposites showed a quite positive half-wave potential (0.80 V vs. RHE), the excellent long-term stability, and the outstanding tolerance to methanol crossing. The improvement in ORR was reasonably attributed to the synergy between N-doped TaOx and N-doped RGO. Elucidating the importance of controlled N-doping for electrocatalysis, this work will open up new opportunities to explore noble-metal-free materials for renewable energy applications.

Ordered PdCu-Based Nanoparticles as Bifunctional Oxygen-Reduction and Ethanol-Oxidation Electrocatalysts

DOE PAGES

Jiang, Kezhu; Wang, Pengtang; Guo, Shaojun; ...

2016-06-02

Here, the development of superior non-platinum electrocatalysts for enhancing the electrocatalytic activity and stability for the oxygen-reduction reaction (ORR) and liquid fuel oxidation reaction is very important for the commercialization of fuel cells,but still agreat challenge.Herein, we demonstrate a new colloidal chemistry technique for making structurally ordered PdCu-based nanoparticles (NPs) with composition control from PdCu to PdCuNi and PtCuCo.Under the dual tuning on the composition and intermetallic phase,the ordered PdCuCo NPs exhibit better activity and much enhanced stability for ORR and ethanol-oxidation reaction (EOR)than those of disordered PdCuM NPs,the commercial Pt/Cand Pd/C catalysts.The density functional theory (DFT)calculations reveal that themore » improved ORR activity on the PdCuM NPs stems from the catalytically active hollow sites arising from the ligand effect and the compressive strain on thePd surface owing to the smaller atomic size of Cu, Co,and Ni.« less

Is Ammonium Peroxydisulate Indispensable for Preparation of Aniline-Derived Iron-Nitrogen-Carbon Electrocatalysts?

PubMed

Xie, Nan-Hong; Yan, Xiang-Hui; Xu, Bo-Qing

2016-09-08

Iron and nitrogen co-doped carbon (Fe-N-C) materials are among the most active non-precious metal catalysts that could replace Pt-based electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries. The synthesis of the Fe-N-C catalysts often involves the use of aniline as the precursor for both N and C and ammonium peroxydisulfate (APS) as an indispensable oxidative initiator for aniline polymerization. Herein, a detailed structure and catalytic ORR performance comparison of aniline-derived Fe-N-C catalysts synthesized with and without the use of APS is reported. The APS-free preparation, which uses Fe(III) ions as the Fe source as well as the aniline polymerization initiator, results in a simple Fe-N-C catalyst with a high activity for the ORR. We show that APS is not necessary for the preparation and even detrimental to the performance of the catalyst. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ordered mesoporous porphyrinic carbons with very high electrocatalytic activity for the oxygen reduction reaction

PubMed Central

Cheon, Jae Yeong; Kim, Taeyoung; Choi, YongMan; Jeong, Hu Young; Kim, Min Gyu; Sa, Young Jin; Kim, Jaesik; Lee, Zonghoon; Yang, Tae-Hyun; Kwon, Kyungjung; Terasaki, Osamu; Park, Gu-Gon; Adzic, Radoslav R.; Joo, Sang Hoon

2013-01-01

The high cost of the platinum-based cathode catalysts for the oxygen reduction reaction (ORR) has impeded the widespread application of polymer electrolyte fuel cells. We report on a new family of non-precious metal catalysts based on ordered mesoporous porphyrinic carbons (M-OMPC; M = Fe, Co, or FeCo) with high surface areas and tunable pore structures, which were prepared by nanocasting mesoporous silica templates with metalloporphyrin precursors. The FeCo-OMPC catalyst exhibited an excellent ORR activity in an acidic medium, higher than other non-precious metal catalysts. It showed higher kinetic current at 0.9 V than Pt/C catalysts, as well as superior long-term durability and MeOH-tolerance. Density functional theory calculations in combination with extended X-ray absorption fine structure analysis revealed a weakening of the interaction between oxygen atom and FeCo-OMPC compared to Pt/C. This effect and high surface area of FeCo-OMPC appear responsible for its significantly high ORR activity. PMID:24056308

Highly Active and Stable Pt–Pd Alloy Catalysts Synthesized by Room‐Temperature Electron Reduction for Oxygen Reduction Reaction

PubMed Central

Wang, Wei; Wang, Zongyuan; Wang, Jiajun; Zhong, Chuan‐Jian

2017-01-01

Carbon‐supported platinum (Pt) and palladium (Pd) alloy catalyst has become a promising alternative electrocatalyst for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. In this work, the synthesis of highly active and stable carbon‐supported Pt–Pd alloy catalysts is reported with a room‐temperature electron reduction method. The alloy nanoparticles thus prepared show a particle size around 2.6 nm and a core–shell structure with Pt as the shell. With this structure, the breaking of O–O bands and desorption of OH are both promoted in electrocatalysis of ORR. In comparison with the commercial Pt/C catalyst prepared by conventional method, the mass activity of the Pt–Pd/C catalyst for ORR is shown to increase by a factor of ≈4. After 10 000‐cycle durability test, the Pt–Pd/C catalyst is shown to retain 96.5% of the mass activity, which is much more stable than that of the commercial Pt/C catalyst. PMID:28435780

Tuning electrocatalytic activity of Pt monolayer shell by bimetallic Ir-M (M=Fe, Co, Ni or Cu) cores for the oxygen reduction reaction

DOE PAGES

Kuttiyiel, Kurian A.; Choi, YongMan; Sasaki, Kotaro; ...

2016-05-18

Here, platinum monolayer electrocatalyst are known to exhibit excellent oxygen reduction reaction (ORR) activity depending on the type of substrate used. Here we demonstrate a relationship between the ORR electrocatalytic activity and the surface electronic structure of Pt monolayer shell induced by various IrM bimetallic cores (M=Fe, Co, Ni or Cu). The relationship is rationalized by comparing density functional theory calculations and experimental results. For an efficient Pt monolayer electrocatalyst, the core should induce sufficient contraction to the Pt shell leading to a downshift of the d-band center with respect to the Fermi level. Depending on the structure of themore » IrM, relative to that of pure Ir, this interaction not only alters the electronic and geometric structure but also induces segregation effects. Combined these effects significantly enhance the ORR activities of the Pt monolayer shell on bimetallic Ir cores electrocatalysts.« less

High Performance Heteroatoms Quaternary-doped Carbon Catalysts Derived from Shewanella Bacteria for Oxygen Reduction.

PubMed

Guo, Zhaoyan; Ren, Guangyuan; Jiang, Congcong; Lu, Xianyong; Zhu, Ying; Jiang, Lei; Dai, Liming

2015-11-25

A novel heteroatoms (N, P, S and Fe) quaternary-doped carbon (HQDC-X, X refers to the pyrolysis temperature) can be fabricated by directly pyrolyzing a gram-negative bacteria, S. oneidensis MR-1 as precursors at 800 °C, 900 °C and 1000 °C under argon atmosphere. These HQDC-X catalysts maintain the cylindrical shape of bacteria after pyrolysis under high temperatures, while heteroatoms including N, P, S and Fe distribute homogeneously on the carbon frameworks. As a result, HQDC-X catalysts exhibit excellent electrocatalytic activity for ORR via a dominant four-electron oxygen reduction pathway in alkaline medium, which is comparable with that of commercial Pt/C. More importantly, HQDC-X catalysts show better tolerance for methanol crossover and CO poisoning effects, long-term durability than commercial Pt/C, which could be promising alternatives to costly Pt-based electrocatalysts for ORR. The method may provide a promising avenue to develop cheap ORR catalysts from inexpensive, scalable and biological recursors.

Effects of ionomer morphology on oxygen reduction on Pt

DOE PAGES

Chlistunoff, Jerzy; Pivovar, Bryan

2015-05-21

In this paper, the oxygen reduction reaction (ORR) at the interface between platinum and Nafion 1100 equivalent weight was studied as a function of temperature (20–80 °C), humidity (10–100%), scan rate, the manner in which Nafion film was deposited, and the state of the Pt surface using ultramicroelectrodes employing cyclic voltammetry and chronoamperometry. ORR on smooth electrodes was strongly inhibited under specific conditions dependent on temperature, humidity, and scan rate. From the data presented, we postulate that dynamic changes in the molecular structure of the ionomer at the platinum interface result in differences in ORR voltammetry for films prepared andmore » equilibrated under different conditions. The lack of similar changes for rough, platinized electrodes has been attributed to differences in initial ionomer structure and a higher energy barrier for ionomer restructuring. Finally, these model system studies yield insight into the ionomer-catalyst interface of particular interest for polymer electrolyte fuel cells.« less

Simple-Cubic Carbon Frameworks with Atomically Dispersed Iron Dopants toward High-Efficiency Oxygen Reduction.

PubMed

Wang, Biwei; Wang, Xinxia; Zou, Jinxiang; Yan, Yancui; Xie, Songhai; Hu, Guangzhi; Li, Yanguang; Dong, Angang

2017-03-08

Iron and nitrogen codoped carbons (Fe-N-C) have attracted increasingly greater attention as electrocatalysts for oxygen reduction reaction (ORR). Although challenging, the synthesis of Fe-N-C catalysts with highly dispersed and fully exposed active sites is of critical importance for improving the ORR activity. Here, we report a new type of graphitic Fe-N-C catalysts featuring numerous Fe single atoms anchored on a three-dimensional simple-cubic carbon framework. The Fe-N-C catalyst, derived from self-assembled Fe 3 O 4 nanocube superlattices, was prepared by in situ ligand carbonization followed by acid etching and ammonia activation. Benefiting from its homogeneously dispersed and fully accessible active sites, highly graphitic nature, and enhanced mass transport, our Fe-N-C catalyst outperformed Pt/C and many previously reported Fe-N-C catalysts for ORR. Furthermore, when used for constructing the cathode for zinc-air batteries, our Fe-N-C catalyst exhibited current and power densities comparable to those of the state-of-the-art Pt/C catalyst.

Higher modes of the Orr-Sommerfeld problem for boundary layer flows

NASA Technical Reports Server (NTRS)

Lakin, W. D.; Grosch, C. E.

1983-01-01

The discrete spectrum of the Orr-Sommerfeld problem of hydrodynamic stability for boundary layer flows in semi-infinite regions is examined. Related questions concerning the continuous spectrum are also addressed. Emphasis is placed on the stability problem for the Blasius boundary layer profile. A general theoretical result is given which proves that the discrete spectrum of the Orr-Sommerfeld problem for boundary layer profiles (U(y), 0,0) has only a finite number of discrete modes when U(y) has derivatives of all orders. Details are given of a highly accurate numerical technique based on collocation with splines for the calculation of stability characteristics. The technique includes replacement of 'outer' boundary conditions by asymptotic forms based on the proper large parameter in the stability problem. Implementation of the asymptotic boundary conditions is such that there is no need to make apriori distinctions between subcases of the discrete spectrum or between the discrete and continuous spectrums. Typical calculations for the usual Blasius problem are presented.

Stability of Full Penetration, Flat Position Weld Pools

NASA Technical Reports Server (NTRS)

Nunes, Arthur C., Jr.; Coan, Al. B.

1999-01-01

The dynamics of the dropthrough distance of a full penetration, flat position weld pool is described. Close to incipient root side penetration the dropthrough is metastable, so that a small drop in power can cause a loss of penetration if not followed soon enough by a compensating rise in power. The SPA (Soft Plasma Arc) process with higher pressure on top of the weld pool loses penetration more quickly than the GTA (Gas Tungsten Arc) process. 2195 aluminum-lithium alloy with a lower surface tension loses penetration more quickly than 2219 aluminum alloy. An instance of loss of penetration of a SPA weld in 2195 aluminum-lithium alloy is discussed in the light of the model.

Synthesis of an excellent electrocatalyst for oxygen reduction reaction with supercritical fluid: Graphene cellular monolith with ultrafine and highly dispersive multimetallic nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yazhou; Cheng, Xiaonong; Yen, Clive H.

Graphene cellular monolith (GCM) can be used as an excellent support for nanoparticles in widespread applications. However, it's still a great challenge to deposit the desirable nanoparticles in GCM that have small size, controllable structure, composition, and high dispersion using the current methods. Here we demonstrate a green, efficient and large-scale method to address this challenge using supercritical fluid (SCF). By this superior method, graphene hydrogel can be transferred into GCM while being deposited with ultrafine and highly dispersive nanoparticles. Specifically, the bimetallic PtFe/GCM and the trimetallic PtFeCo/GCM catalysts are successfully synthesized, and their electrocatalytic performances toward oxygen reduction reactionmore » (ORR) are also studied. The resultant PtFe/GCM shows the significant enhancement in ORR activity, including a factor of 8.47 enhancement in mass activity (0.72 A mgPt-1), and a factor of 7.67 enhancement in specific activity (0.92 mA cm-2), comparing with those of the commercial Pt/C catalyst (0.085 A mgPt-1, 0.12 mA cm-2). Importantly, by introducing the Co, the trimetallic PtFeCo/GCM exhibits the further improved ORR activities (1.28 A mgPt-1, 1.80 mA cm-2). The high ORR activity is probably attributed to the alloying structure, ultrafine size, highly dispersive, well-defined, and a better interface with 3D porous graphene support.« less

Correlation of cetuximab-induced skin rash and outcomes of solid tumor patients treated with cetuximab: a systematic review and meta-analysis.

PubMed

Abdel-Rahman, Omar; Fouad, Mona

2015-02-01

We performed a systematic review and meta-analysis of the correlation between cetuximab-induced skin rash and outcomes of solid tumor patients treated with cetuximab. Eligible studies included phase I, II and III trials of patients with solid tumors on cetuximab; describing events of skin rash and correlating skin rash with overall survival (OS), progression free survival (PFS) and/or overall response rate (ORR). Our search strategy yielded 409 potentially relevant citations on CETUXIMAB from Pubmed/Medline, CENTRAL Cochrane registry and ASCO meeting library. After exclusion of ineligible studies, a total of 13 clinical trials were considered eligible for the meta-analysis, including 4 phase III trials, 8 phase II trials and one phase I trial. The occurrence of cetuximab-induced rash in patients was highly associated with improvements in PFS (HR=0.74; 95% CI: 0.63-0.86, P<0.0002), OS (HR=0.60; 95% CI: 0.47-0.76, P<0.0001), and ORR (RR=1.51, 95% CI: 1.26-1.81, P<0.00001), as compared to patients without rash. Exploratory subgroup analysis showed no effect of tumor types on the RR of ORR. Our meta-analysis has demonstrated that cetuximab-induced rash is associated with a significantly improved OS, PFS and ORR. Cetuximab-induced skin rash may represent a prognostic factor in patients with advanced solid tumors. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A combination of CoO and Co nanoparticles supported on electrospun carbon nanofibers as highly stable air electrodes

NASA Astrophysics Data System (ADS)

Alegre, Cinthia; Busacca, Concetta; Di Blasi, Orazio; Antonucci, Vincenzo; Aricò, Antonino Salvatore; Di Blasi, Alessandra; Baglio, Vincenzo

2017-10-01

Bifunctional materials able to catalyze both the oxygen reduction (ORR) and the oxygen evolution (OER) reactions in alkaline media are still a challenge for the progress of energy conversion and storage devices such as metal-air batteries or unitized regenerative fuel cells. In this work, carbon nanofibers synthesized by electrospinning are modified with a combination of cobalt oxide and metallic cobalt (CoO-Co/CNF) and studied as a bifunctional air electrode for metal-air batteries. The performance of CoO-Co/CNF for both reactions is compared with state-of-the-art catalysts such as Pt/C and IrO2. The combination of cobalt oxide and metallic cobalt, finely distributed on the surface of graphitic carbon nanofibers, leads to a bifunctional catalyst with a half-wave potential for the ORR slightly better than Pt/C and a reversibility (ΔEOER-ORR) of 809 mV. The stability of CoO-Co/CNF is assessed by means of different stress tests: polarizations at high electrochemical potentials (2 V vs. RHE), rapid charge-discharge cycles at ±80 mA cm-2 and long durability tests by charging for 12 h at 60 mA cm-2 and discharging for 8 h at -80 mA cm-2. CoO-Co/CNF shows a remarkable stability, maintaining, at least, an 82% of its performance for the ORR after the stress tests, even when cycled for more than 100 h.

Synthesis of an excellent electrocatalyst for oxygen reduction reaction with supercritical fluid: Graphene cellular monolith with ultrafine and highly dispersive multimetallic nanoparticles

NASA Astrophysics Data System (ADS)

Zhou, Yazhou; Cheng, Xiaonong; Yen, Clive H.; Wai, Chien M.; Wang, Chongmin; Yang, Juan; Lin, Yuehe

2017-04-01

Graphene cellular monolith (GCM) can be used as an excellent support for nanoparticles in widespread applications. However, it's still a great challenge to deposit the desirable nanoparticles in GCM that have small size, controllable structure, composition, and high dispersion using the current methods. Here we demonstrate a green, efficient and large-scale method to address this challenge using supercritical fluid (SCF). By this superior method, graphene hydrogel can be transferred into GCM while being deposited with ultrafine and highly dispersive nanoparticles. Specifically, the bimetallic PtFe/GCM and the trimetallic PtFeCo/GCM catalysts are successfully synthesized, and their electrocatalytic performances toward oxygen reduction reaction (ORR) are also studied. The resultant PtFe/GCM shows the significant enhancement in ORR activity, including a factor of 8.47 enhancement in mass activity (0.72 A mgPt-1), and a factor of 7.67 enhancement in specific activity (0.92 mA cm-2), comparing with those of the commercial Pt/C catalyst (0.085 A mgPt-1, 0.12 mA cm-2). Importantly, by introducing the Co, the trimetallic PtFeCo/GCM exhibits the further improved ORR activities (1.28 A mgPt-1, 1.80 mA cm-2). The high ORR activity is probably attributed to the alloying structure, ultrafine size, highly dispersive, well-defined, and a better interface with 3D porous graphene support.

Multicenter Phase II Study with Weekly Bendamustine and Paclitaxel as First- or Later-Line Therapy in Patients with Metastatic Breast Cancer: RiTa II Trial.

PubMed

Loibl, Sibylle; Doering, Gabriele; Müller, Lothar; Grote-Metke, Albert; Müller, Roberto; Tomé, Oliver; Wiest, Wolfgang; Maisch, Andrea; Nekljudova, Valentina; von Minckwitz, Gunter

2011-12-01

The combination of bendamustine (B) and paclitaxel (P) as anthracycline-free treatment option in patients with advanced breast cancer has been evaluated in the previous RiTa I trial. The regimen of weekly B 70 mg/m(2) and P 90 mg/m(2) with a pause every 4th week was established as an effective regimen with low toxicity. The aim of the present RiTa II study was to investigate the potential of BP as anthracycline-free combination therapy. The primary objective was to determine the progression-free survival (PFS); secondary endpoints were safety, tolerability, overall response rate (ORR) and overall survival (OS). 26 patients were available, 15 received BP as first-line, 11 as beyond first-line treatment. 27% patients had triple-negative breast cancer (TNBC). Median PFS and OS were 7.3 months (95% confidence interval (CI): 5.5-10.9) and 14.9 months (95% CI: 9.9-22.9), respectively. The 1-year PFS rate was 20.3% and the 1-year OS rate 71.2%. The ORR was 42.3%, including 4 complete and 7 partial remissions. TNBC patients reached an ORR of 71.4%. Anthracycline-pretreated patients showed an ORR of 43.8%, confirming bendamustine's lack of cross-resistance to anthracycline agents. BP represents a favorable option with moderate toxicity in pretreated metastatic breast cancer and offers a possibility for application in anthracycline-pretreated and TNBC patients.

Self-Assembled Nanomicelles as MRI Blood-Pool Contrast Agent.

PubMed

Babič, Andrej; Vorobiev, Vassily; Xayaphoummine, Céline; Lapicorey, Gaëlle; Chauvin, Anne-Sophie; Helm, Lothar; Allémann, Eric

2018-01-26

Gadolinium-loaded nanomicelles show promise as future magnetic resonance imaging (MRI) contrast agents (CAs). Their increased size and high gadolinium (Gd) loading gives them an edge in proton relaxivity over smaller molecular Gd-complexes. Their size and stealth properties are fundamental for their long blood residence time, opening the possibility for use as blood-pool contrast agents. Using l-tyrosine as a three-functional scaffold we synthesized a nanostructure building block 8. The double C18 aliphatic chain on one side, Gd-1,4,7,10-tetraazacyclododecane-1-4-7-triacetic acid (Gd-DO3A) with access to bulk water in the center and 2 kDa PEG on the hydrophilic side gave the amphiphilic properties required for the core-shell nanomicellar architecture. The self-assembly into Gd-loaded monodispersed 10-20 nm nanomicelles occurred spontaneously in water. These nanomicelles (Tyr-MRI) display very high relaxivity at 29 mm -1  s -1 at low field strength and low cytotoxicity. Good contrast enhancement of the blood vessels and the heart together with prolonged circulation time in vivo, makes Tyr-MRI an excellent candidate for a new supramolecular blood-pool MRI CA. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective financing of maternal health services: a review of the literature.

PubMed

Ensor, Tim; Ronoh, Jeptepkeny

2005-12-01

Health care can be funded in a number of ways ranging from direct user charges (out of pocket) payments to indirect methods that pool across time (prepayment) and across different risk and wealth groups (insurance and general taxation). All these methods can be used to finance maternal health services. When assessing the impact of financing mechanisms it is important to be aware of the different ways they effect service delivery patterns and utilisation. Specifically most systems have both equity and efficiency aspects that combine to impact on health service utilisation and health status. In general indirect methods that help families to pool the costs of maternal health services are preferable to direct methods of payment. It is also clear, however, that user charges may sometimes help to mitigate deficiencies in systems of pooled funding. Available literature suggests that financing mechanisms for maternal health services could be improved by systems that increase transparency, help to mitigate demand-side costs of services and provide funding for that promote transparent charging for services. While the limited experience of demand-side mechanisms for improving access to maternal health services more evaluation is required.

59. May 1985. DEPENDENCIES NORTHWEST OF MAIN HOUSE, LOOKING WEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

59. May 1985. DEPENDENCIES NORTHWEST OF MAIN HOUSE, LOOKING WEST FROM PORTE COCHERE OF NORTH WING (Path in center of view leads to northwestern quadrant of formal garden plan where swimming pool lies. Dependencies, from left to right: Kitchen-Storehouse, tool shed, cistern, pump house, then Smokehouse in right foreground) - Borough House, West Side State Route 261, about .1 mile south side of junction with old Garners Ferry Road, Stateburg, Sumter County, SC

Photoregenerative I⁻/I₃⁻ couple as a liquid cathode for proton exchange membrane fuel cell.

PubMed

Liu, Zhen; Wang, Yadong; Ai, Xinping; Tu, Wenmao; Pan, Mu

2014-10-28

A photoassisted oxygen reduction reaction (ORR) through I(-)/I3(-) redox couple was investigated for proton exchange membrane (PEM) fuel cell cathode reaction. The I(-)/I3(-)-based liquid cathode was used to replace conventional oxygen cathode, and its discharge product I(-) was regenerated to I3(-) by photocatalytic oxidation with the participation of oxygen. This new and innovative approach may provide a strategy to eliminate the usage of challenging ORR electrocatalysts, resulting in an avenue for developing low-cost and high-efficiency PEM fuel cells.

Advancements in rationally designed PGM-free fuel cell catalysts derived from metal–organic frameworks

DOE PAGES

Barkholtz, Heather M.; Liu, Di -Jia

2016-11-14

Over the past several years, metal-organic framework (MOF)-derived platinum group metal free (PGM-free) electrocatalysts have gained considerable attention due to their high efficiency and low cost as potential replacement for platinum in catalyzing oxygen reduction reaction (ORR). In this review, we summarize the recent advancements in design, synthesis and characterization of MOF-derived ORR catalysts and their performances in acidic and alkaline media. As a result, we also discuss the key challenges such as durability and activity enhancement critical in moving forward this emerging electrocatalyst science.

Dynamics of skirting droplets

NASA Astrophysics Data System (ADS)

Akers, Caleb; Hale, Jacob

2014-11-01

It has been observed that non-coalescence between a droplet and pool of like fluid can be prolonged or inhibited by sustained relative motion between the two fluids. In this study, we quantitatively describe the motion of freely moving droplets that skirt across the surface of a still pool of like fluid. Droplets of different sizes and small Weber number were directed horizontally onto the pool surface. After stabilization of the droplet shape after impact, the droplets smoothly moved across the surface, slowing until coalescence. Using high-speed imaging, we recorded the droplet's trajectory from a top-down view as well as side views both slightly above and below the fluid surface. The droplets' speed is observed to decrease exponentially, with the smaller droplets slowing down at a greater rate. Droplets infused with neutral density micro beads showed that the droplet rolls along the surface of the pool. A qualitative model of this motion is presented.

Aidi injection combined with radiation in the treatment of non-small cell lung cancer: A meta-analysis evaluation the efficacy and side effects.

PubMed

Zhang, Hongzhi; Jiang, Huijuan; Hu, Xigang; Jia, Zongling

2015-08-01

The purpose of this meta-analysis was to assess the clinical efficacy and side effects of Aidi injection combined with radiation in the treatment of non-small cell lung cancer (NSCLC). By searching PubMed, the Cochrane central register of controlled trials, EMBSE and CNKI databases, the efficacy and side effect data of Aidi injection combined with radiation in the treatment of NSCLC from the published clinical studies were collected. The data were pooled using Stata version 11.0 software (http://www.stata.com; Stata Corporation, College Station, TX). Ten clinical studies with 1084 subjects were included in this meta-analysis. The combined data showed the clinical efficacy in experiment group was higher than that of control group (risk ratio [RR] = 1.72, 95% confidence interval [CI]: 1.52-1.96, P = 0.00); four articles reported the life quality improvement. The pooled data showed that the use of Aidi can significantly improve the quality of life in the procedure of radiation (RR = 2.29, 95% CI: 1.76-2.98, P = 0.00); six studies reported the radiation toxicities. The pooled data showed that Aidi injection can significant decrease the radiation pneumonia (OR = 0.46, 95% CI: 0. 34-0.63), radiation esophagitis (OR = 0.53, 95% CI: 0.40-0.71), and marrow suppression (OR = 0.50, 95% CI: 0.42-0.59). Aidi injection can improve the clinical efficacy, quality of life, and decrease the radiation-related toxicities in NSCLC patients who received radiation.

Correlation of Hypertension and Proteinuria with Outcome in Elderly Bevacizumab-Treated Patients with Metastatic Colorectal Cancer

PubMed Central

Feliu, Jaime; Salud, Antonieta; Safont, Maria J.; García-Girón, Carlos; Aparicio, Jorge; Losa, Ferran; Bosch, Carlos; Escudero, Pilar; Casado, Enrique; Jorge, Monica; Bohn, Uriel; Pérez-Carrión, Ramon; Carmona, Alberto; Custodio, Ana B.; Maurel, Joan

2015-01-01

Background Studies suggest a relationship between hypertension and outcome in bevacizumab-treated patients with metastatic colorectal cancer (mCRC). We performed a retrospective analysis of two phase II studies (BECA and BECOX) to determine if hypertension and proteinuria predict outcome in elderly patients with mCRC treated with bevacizumab. Patients and Methods Patients ≥70 years of age received either capecitabine 1250 mg/m2 bid days 1–14 + bevacizumab 7.5 mg/kg day 1 every 21 days (BECA study) or capecitabine 1000 mg/m2 bid days 1–14 with bevacizumab 7.5 mg/kg and oxaliplatin 130 mg/m2 day 1 (BECOX study). The primary objective was to correlate hypertension and proteinuria with overall response rate (ORR), time to progression (TTP) and overall survival (OS). Secondary objectives included identification of risk factors associated with the development of hypertension and proteinuria and determining whether development of hypertension or proteinuria in the first 2 cycles was related to ORR, disease-control rate (DCR), TTP or OS. Results In total, 127 patients (median age 75.5 years) were included in the study. Hypertension correlated with DCR and OS; proteinuria correlated with ORR and DCR. Proteinuria or hypertension in the first 2 cycles did not correlate with efficacy. Risk factors for hypertension were female gender (odds ratio [OR] 0.241; P = 0.011) and more bevacizumab cycles (OR 1.112; P = 0.002); risk factors for proteinuria were diabetes (OR 3.869; P = 0.006) and more bevacizumab cycles (OR 1.181; P<0.0001). Multivariate analysis identified as having prognostic value: baseline lactate dehydrogenase, haemoglobin, number of metastatic lesions and DCR. Conclusion This analysis of two phase II studies suggests that hypertension is significantly correlated with OS but not with ORR and TTP, whereas proteinuria is correlated with ORR but not with OS and TTP. Both hypertension and proteinuria are associated with the duration of bevacizumab treatment and do not represent an independent prognostic factor. PMID:25602286

Emerging beliefs frustrate ecological literacy and meaning-making for students

NASA Astrophysics Data System (ADS)

Fleischer, Stuart

2011-03-01

In their treatise, Mitchell and Mueller extend David Orr's notions of ecological literacy (2005) to include biophilia (Wilson 1984) and ecojustice (Mueller 2009). In his writings, David Orr claims that the US is in an "ecological crisis" and that this stems from a crisis of education. The authors outline Orr's theory of ecological literacy as a lens to understand Earth's ecology in view of long-term survival. In their philosophical analysis of Orr's theory, Mitchell and Mueller argue that we move beyond the "shock doctrine" perspective of environmental crisis. By extending Orr's concept of ecological literacy to include biophilia and ecojustice, and by recognizing the importance of experience-in-learning, the authors envision science education as a means to incorporate values and morals within a sustainable ideology of educational reform. Through this forum, I reflect on the doxastic logic and certain moral and social epistemological concepts that may subsequently impact student understanding of ecojustice, biophilia, and moral education. In addition, I assert the need to examine myriad complexities of assisting learners to become ecologically literate at the conceptual and procedural level (Bybee in Achieving scientific literacy: from purposes to practices, Heinemann Educational Books, Portsmouth, 1997), including what Kegan (In over our heads: the mental demands of modern life, Harvard University Press, Cambridge, 1994) refers to as "Third Order" and "Fourth Order" thinking: notions of meaning-construction or meaning-organizational capacity to understand good stewardship of the Earth's environment. Learners who are still in the process of developing reflective and metacognitive skills "cannot have internal conversation about what is actual versus what is possible, because no `self' is yet organized that can put these two categories together" (p. 34). Mitchell and Mueller indicate that middle school learners should undergo a transformation in order to reflect critically about the environment with a view toward determining critical truths about the world. However, if this audience lacks "selective, interpretive, executive, construing capacities" (Kegan in In over our heads: The mental demands of modern life, 1994, p. 29), assimilating the notions of ecojustice and biophia may be problematic.

Total Skin Electron Beam for Primary Cutaneous T-cell Lymphoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elsayad, Khaled; Kriz, Jan; Moustakis, Christos

Purpose: Recent trials with low-dose total skin electron beam (TSEB) therapy demonstrated encouraging results for treating primary cutaneous T-cell lymphoma (PCTCL). In this study, we assessed the feasibility of different radiation doses and estimated survival rates of different pathologic entities and stages. Methods and Materials: We retrospectively identified 45 patients with PCTCL undergoing TSEB therapy between 2000 and 2015. Clinical characteristics, treatment outcomes, and toxicity were assessed. Results: A total of 49 courses of TSEB therapy were administered to the 45 patients. There were 26 pathologically confirmed cases of mycosis fungoides (MF) lymphoma, 10 cases of Sézary syndrome (SS), andmore » 9 non-MF/SS PCTCL patients. In the MF patients, the overall response rate (ORR) was 92% (50% complete remission [CR]), 70% ORR in SS patients (50% CR), and 89% ORR in non-MF/SS patients (78% CR). The ORR for MF/SS patients treated with conventional dose (30-36 Gy) regimens was 92% (63% CR) and 75% (25% CR) for low-dose (<30-Gy) regimens (P=.09). In MF patients, the overall survival (OS) was 77 months with conventional dose regimens versus 14 months with low-dose regimens (P=.553). In SS patients, the median OS was 48 versus 16 months (P=.219), respectively. Median event-free survival (EFS) for MF in conventional dose patients versus low-dose patients was 15 versus 8 months, respectively (P=.264) and 19 versus 3 months for SS patients (P=.457). Low-dose regimens had shorter treatment time (P=.009) and lower grade 2 adverse events (P=.043). A second TSEB course was administered in 4 MF patients with 100% ORR. There is a possible prognostic impact of supplemental/boost radiation (P<.001); adjuvant treatment (P<.001) and radiation tolerability (P=.021) were detected. Conclusions: TSEB therapy is an efficacious treatment modality in the treatment of several forms of cutaneous T-cell lymphoma. There is a nonsignificant trend to higher and longer clinical benefit for MF and SS patients receiving conventional dose. Low-dose TSEB regimens are well tolerated and achieve short-term palliation.« less

Efficacy and bleeding profile of a combined oral contraceptive containing oestradiol valerate/dienogest: a pooled analysis of three studies conducted in North America and Europe.

PubMed

Nelson, Anita; Parke, Susanne; Makalova, Dagmar; Serrani, Marco; Palacios, Santiago; Mellinger, Uwe

2013-08-01

To summarise all clinical data on the contraceptive efficacy and bleeding profile associated with an oestradiol valerate (E2V) and dienogest (DNG) [E2V/DNG] combined oral contraceptive (COC) derived from Phase III trials. Pooled analysis of three large-scale multicentre trials conducted in healthy women who received oral E2V/DNG for 7 to 28 cycles (28-day cycles). A total of 2266 women were included in this analysis. Overall, 19 pregnancies occurred over 13 cycles during 880,950 days of relevant exposure (Pearl Index [PI] of 0.79; upper limit of the two-sided 95% confidence interval [CI]: 1.23). Ten pregnancies attributed to method failure came about during 871,091 days of relevant exposure (adjusted PI of 0.42; upper limit of the two-sided 95% CI: 0.77). In women aged 18 to 35 years (n = 1687), the corresponding PI and adjusted PI were 1.01 (upper limit of the two-sided 95% CI: 1.59) and 0.51 (upper limit of the two-sided 95% CI: 0.97), respectively. In the first 13 cycles of treatment, 76 to 81% of women experienced scheduled withdrawal bleeding, and 13 to 23% experienced intracyclic bleeding. E2V/DNG provides reliable contraceptive efficacy in women aged 18 to 50 years.

Promotion of Oxygen Reduction by Exsolved Silver Nanoparticles on a Perovskite Scaffold for Low-Temperature Solid Oxide Fuel Cells.

PubMed

Zhu, Yinlong; Zhou, Wei; Ran, Ran; Chen, Yubo; Shao, Zongping; Liu, Meilin

2016-01-13

Solid oxide fuel cells (SOFCs) have potential to be the cleanest and most efficient electrochemical energy conversion devices with excellent fuel flexibility. To make SOFC systems more durable and economically competitive, however, the operation temperature must be significantly reduced, which depends sensitively on the development of highly active electrocatalysts for oxygen reduction reaction (ORR) at low temperatures. Here we report a novel silver nanoparticle-decorated perovskite oxide, prepared via a facile exsolution process from a Sr0.95Ag0.05Nb0.1Co0.9O3-δ (SANC) perovskite precursor, as a highly active and robust ORR electrocatalyst for low-temperature SOFCs. The exsolved Sr0.95Ag0.05Nb0.1Co0.9O3-δ (denoted as e-SANC) electrode is very active for ORR, achieving a very low area specific resistance (∼0.214 Ω cm(2) at 500 °C). An anode-supported cell with the new heterostructured cathode demonstrates very high peak power density (1116 mW cm(-2) at 500 °C) and stable operation for 140 h at a current density of 625 mA cm(-2). The superior ORR activity and stability are attributed to the fast oxygen surface exchange kinetics and the firm adhesion of the Ag nanoparticles to the Sr0.95Nb0.1Co0.9O3-δ (SNC0.95) support. Moreover, the e-SANC cathode displays improved tolerance to CO2. These unique features make the new heterostructured material a highly promising cathode for low-temperature SOFCs.

Bimetal–Organic Framework Self-Adjusted Synthesis of Support-Free Nonprecious Electrocatalysts for Efficient Oxygen Reduction

DOE PAGES

You, Bo; Jiang, Nan; Sheng, Meili; ...

2015-10-22

The development of low-cost catalysts with oxygen reduction reaction (ORR) activity superior to that of Pt for fuel cells is highly desirable but remains challenging. Herein, we report a bimetal-organic framework (bi-MOF) self-adjusted synthesis of support-free porous Co-N-C nanopolyhedron electrocatalysts by pyrolysis of a Zn/Co bi-MOF without any post-treatments. The presence of initial Zn forms a spatial isolation of Co that suppresses its sintering during pyrolysis, and Zn evaporation also promotes the surface area of the resultant catalysts. The composition, morphology, and hence ORR activity of Co-N-C could be tuned by the Zn/Co ratio. The optimal Co-N-C exhibited remarkable ORRmore » activity with a half-wave potential of 0.871 V versus the reversible hydrogen electrode (RHE) (30 mV more positive than that of commercial 20 wt % Pt/C) and a kinetic current density of 39.3 mA cm -2 at 0.80 V versus RHE (3.1 times that of Pt/C) in 0.1 M KOH, and excellent stability and methanol tolerance. It also demonstrated ORR activity comparable to and stability much higher than those of Pt/C in acidic and neutral electrolytes. Various characterization techniques, including X-ray absorption spectroscopy, revealed that the superior activity and strong stability of Co-N-C originated from the intense interaction between Co and N, the high content of ORR active pyridinic and pyrrolic N, and the large specific surface area.« less

Salt melt synthesis of curved nitrogen-doped carbon nanostructures: ORR kinetics boost

NASA Astrophysics Data System (ADS)

Rybarczyk, Maria K.; Gontarek, Emilia; Lieder, Marek; Titirici, Maria-Magdalena

2018-03-01

Implementing metal-free electrocatalysts for the oxygen reduction reaction (ORR) and revealing crucial chemical or topographical parameters driving their activity are vital for the development of power cells. The carbon-based catalysts are very often synthesized through carbonization of biopolymers, in particular, those one containing nitrogen groups such as chitosan. Unfortunately, the resulting carbonaceous materials usually lack specific porosity and exhibit low catalytic activity. Here, we demonstrate that pyrolysis of chitosan in a ZnCl2 melt assisted by the presence of LiCl results not only in a highly porous activated carbon material with a specific surface area of 1317.97 m2/g and the total nitrogen content of 6.5%, but also induces unexpected curvature in the grown graphitic layers. This is the first work that shows curved graphene layers obtained from a biopolymer precursor by its pyrolytic decomposition in the melted salt media. On the other hand, a carbonaceous material obtained from chitosan but without the salts has very low specific surface area of 7.8 m2/g, possesses no specific structural features, and contains 4.7% of nitrogen. The electrochemical studies show, that the former material is highly active towards four-electron pathway of the ORR in terms of an onset potential (0.89 V vs RHE) and the turnover frequency (TOFmax = 0.095 e site-1 s-1). We attribute this high catalytic performance to the presence of the pyridinic and pyrrolic sites in the structure. The ORR kinetics is probably further promoted by curvature in the graphitic layers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Wenqiang; School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003; Liu, Minmin

We present the synthesis and multifunctional utilization of core-satellite carbon-Fe{sub 3}O{sub 4} nanoparticles to serve as the enabling platform for a range of applications including oxygen reduction reaction (ORR) and magnetic adsorbent. Starting from polydopamine (PDA) nanoparticles and Fe(NO{sub 3}){sub 3}, carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. The synergistic combination of Fe{sub 3}O{sub 4} and N-doped carbon endows the nanocomposite with high electrochemical activity in ORR and mainly four electrons transferred in reaction process. Furthermore, carbon-Fe{sub 3}O{sub 4} nanoparticles used as magnetic adsorbent exhibit the efficient removal of Rhodamine B frommore » an aqueous solution. The recovery and reuse of the adsorbent is demonstrated 5 times without any detectible loss in activity. - Graphical abstract: Starting from polydopamine (PDA) nanoparticles and Fe(NO{sub 3}){sub 3}, carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. The nanocomposites serve as the enabling platform for a range of applications including oxygen reduction reaction (ORR) and magnetic adsorbent. - Highlights: • Carbon-Fe{sub 3}O{sub 4} core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. • Polydopamine and Fe(NO{sub 3}){sub 3} are precursors for N-doped carbon source and Fe{sub 3}O{sub 4} nanoparticles, respectively. • The nanocomposites exhibit high electrochemical activity in ORR. • The nanocomposites effectively adsorb organic dyes with magnetic recovery and good recycle property.« less

Comparison of Ifosfamide, Carboplatin and Etoposide versus Etoposide, Steroid, and Cytarabine Cisplatin as Salvage Chemotherapy in Patients with Refractory or Relapsed Hodgkin's lymphoma

PubMed Central

Mehrzad, Valiollah; Ashrafi, Farzaneh; Farrashi, Ali Reza; Pourmarjani, Reyhaneh; Dehghani, Mehdi; Shahsanaei, Armindokht

2017-01-01

Background: Refractory or relapsed Hodgkin's disease (HD) occurs in 10-50% of patients. The treatment of choice for these patients is high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). Response to salvage chemotherapy (SCT) partial remission (PR) is necessary before HDCT with ASCT. However, its applicability is restricted mostly to patients responding to salvage chemotherapy. Optimal salvage regimen for these patients is unclear. In this study, our aim was to compare the efficacy profiles of ifosfamide, carboplatin, and etoposide (ICE) and etoposide-steroid-cytarabine-cisplatin (ESHAP) (cytosine arabinoside, cisplatin, and dexamethasone) regimens in the salvage treatment of relapsed or refractory HD. Materials and Methods: In this retrospective analysis, 114 patients with primary refractory or relapsed HD who received ICE or ESHAP salvage regimen were included. Results: Of 114 patients, 47 (41.2%) were females and the median age was 31.5 years. Response could be evaluated in 114 patients. Of 114 patients, 38 (33%) achieved complete remission (CR) and 21 (18.4%) achieved PR, leading to an overall response rate (ORR: CR + PR) of 51.4%. In the evaluable ICE group (n = 41), rates of CR, PR, and ORR were 21.9%, 17.1%, and 39% and in the ESHAP group (n = 73), rates of CR, PR, and ORR were 39.7%, 19.2%, and 58.9% (for ORR, P = 0.04), respectively. Conclusion: In patients with relapsed or refractory HD, treatment with ESHAP seems to have higher rates of response than ICE regimen does. PMID:28401077

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model.

PubMed

Hikida, Takuji; Yamaguchi, Masaru; Shimizu, Mami; Kikuta, Jun; Yoshino, Tomokazu; Kasai, Kazutaka

2016-07-01

Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR.

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model

PubMed Central

Hikida, Takuji; Shimizu, Mami; Kikuta, Jun; Yoshino, Tomokazu; Kasai, Kazutaka

2016-01-01

Objective Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Methods Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. Results On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. Conclusions These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR. PMID:27478800

Boosting Bifunctional Oxygen Electrolysis for N-Doped Carbon via Bimetal Addition.

PubMed

Wang, Jian; Ciucci, Francesco

2017-04-01

The addition of transition metals, even in a trace amount, into heteroatom-doped carbon (M-N/C) is intensively investigated to further enhance oxygen reduction reaction (ORR) activity. However, the influence of metal decoration on the electrolysis of the reverse reaction of ORR, that is, oxygen evolution reaction (OER), is seldom reported. Moreover, further improving the bifunctional activity and corrosion tolerance for carbon-based materials remains a big challenge, especially in OER potential regions. Here, bimetal-decorated, pyridinic N-dominated large-size carbon tubes (MM'-N/C) are proposed for the first time as highly efficient and durable ORR and OER catalysts. FeFe-N/C, CoCo-N/C, NiNi-N/C, MnMn-N/C, FeCo-N/C, NiFe-N/C, FeMn-N/C, CoNi-N/C, MnCo-N/C, and NiMn-N/C are systematically investigated in terms of their structure, composition, morphology, surface area, and active site densities. In contrast to conventional monometal and N-decorated carbon, small amounts of bimetal (≈2 at%) added during the one-step template-free synthesis contribute to increased pyridinic N content, much longer and more robust carbon tubes, reduced metal particle size, and stronger coupling between the encapsulated metals and carbon support. The synergy of those factors accounts for the dramatically improved ORR and OER activity and stability. By comparison, NiFe-N/C and MnCo-N/C stand out and achieve superior bifunctional oxygen catalytic performance, exceeding most of state-of-the-art catalysts. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxygen reduction reaction catalyzed by platinum nanonetwork prepared by template free one step synthesis for polymer electrolyte membrane fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narayanamoorthy, B.; Kumar, B.V.V.S. Pavan; Eswaramoorthy, M.

2014-07-01

Highlights: • Supportless Pt nanonetwork (Pt NN) synthesized by novel template free one step method as per our earlier reported procedure. • Electrocatalytic activity of Pt NN studied taking oxygen reduction reaction in acid medium. • Kinetic and thermodynamic parameters were deduced under hydrodynamic conditions. • ORR mechanistic pathway was proposed based on kinetic rate constants. • ADT analysis found enhanced stability (5000 cycles) for Pt NN than Pt NN/VC and reported Pt/C. - Abstract: The reduction reaction of molecular oxygen (ORR) was investigated using supportless Pt nanonetwork (Pt NN) electrocatalyst in sulfuric acid medium. Pt NN was prepared bymore » template free borohydride reduction. The transmission electron microscope images revealed a network like nano-architecture having an average cluster size of 30 nm. The electrochemical characterization of supportless and Vulcan carbon supported Pt NN (Pt NN/VC) was carried out using rotating disc and ring disc electrodes at various temperatures. Kinetic and thermodynamic parameters were estimated under hydrodynamic conditions and compared with Pt NN/VC and reported Pt/C catalysts. The accelerated durability test revealed that supportless Pt NN is quite stable for 5000 potential cycles with 22% reduction in electrochemical surface area (ECSA). While the initial limiting current density has in fact increased by 11.6%, whereas Pt NN/VC suffered nearly 55% loss in ECSA and 13% loss in limiting current density confirming an enhanced stability of supportless Pt NN morphology for ORR compared to conventional Pt/C ORR catalysts in acid medium.« less

A&M. TAN607. Construction view, facing southwest. At upper left of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

A&M. TAN-607. Construction view, facing southwest. At upper left of view, north-wall equipment and operating galleries take shape on hot shop. Pumice-block side of storage pool section in center left of view. Water filter building (TAN-608) next to north wall of pool. Hot liquid waste building (TAN-616) at right of view. Note concrete construction of TAN-608 and 616. Date: January 18, 1954. INEEL negative no. 9604 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Multifunctional nanostructured electrocatalysts for energy conversion and storage: current status and perspectives.

PubMed

Ghosh, Srabanti; Basu, Rajendra N

2018-06-21

Electrocatalytic oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) have attracted widespread attention because of their important role in the application of various energy storage and conversion devices, such as fuel cells, metal-air batteries and water splitting devices. However, the sluggish kinetics of the HER/OER/ORR and their dependency on expensive noble metal catalysts (e.g., Pt) obstruct their large-scale application. Hence, the development of efficient and robust bifunctional or trifunctional electrocatalysts in nanodimension for both oxygen reduction/evolution and hydrogen evolution reactions is highly desired and challenging for their commercialization in renewable energy technologies. This review describes some recent developments in the discovery of bifunctional or trifunctional nanostructured catalysts with improved performances for application in rechargeable metal-air batteries and fuel cells. The role of the electronic structure and surface redox chemistry of nanocatalysts in the improvement of their performance for the ORR/OER/HER under an alkaline medium is highlighted and the associated reaction mechanisms developed in the recent literature are also summarized.

Mechlorethamine, vincristine, melphalan and prednisone (MOMP) for the treatment of relapsed lymphoma in dogs.

PubMed

Back, A R; Schleis, S E; Smrkovski, O A; Lee, J; Smith, A N; Phillips, J C

2015-12-01

Eighty-eight dogs with relapsed lymphoma were treated with the MOMP (mechlorethamine, vincristine, melphalan and prednisone) protocol on a 28-day treatment cycle. The overall response rate (ORR) to the MOMP protocol was 51.1% for a median of 56 days (range 7-858 days). Twelve percent of dogs experienced a complete response for a median of 81 days (range 42-274 days) and 38.6% experienced a partial response for a median of 49 days (range 7-858 days). Dogs with T-cell lymphoma had an ORR of 55% for a median of 60 days (range 49-858 days) while those with B-cell lymphoma had an ORR of 57% for a median of 81 days (range 7-274 days) (P = 0.783). The overall survival time for all dogs was 183 days (range 17-974 days). Fifty-four percent of dogs experienced toxicity with the majority classified as grade I. The MOMP protocol seems well-tolerated and is an option for dogs with relapsed lymphoma. © 2013 John Wiley & Sons Ltd.

The effect of high anionomer loading with silver nanowire catalysts on the oxygen reduction reaction in alkaline environment

NASA Astrophysics Data System (ADS)

Lemke, Adam J.; O'Toole, Alexander W.; Phillips, Richard S.; Eisenbraun, Eric T.

2014-06-01

The effect of ionomer content on the oxygen kinetics in fuel cells and metal-oxide batteries was investigated by varying ionomer loading with constant loadings of a silver nanowire catalyst. Silver nanowire inks were produced in which commercially available anionomer solution constituted 10, 25, 40, 50, and 75% of the total ink volume. Constant loadings of Ag nanowire catalyst were then deposited onto glassy carbon electrodes by varying the amount of ink deposited. These were then used in rotating disc electrode (RDE) experiments using a 0.1 M KOH electrolyte solution. From these experiments, using ORR polarization curves and Koutecky-Levich analysis, it was found that not only did the anionomer loading affect the total activity (given a constant Ag nanowire loading) but, that the anionomer content also had an impact upon the apparent kinetic limited current as well as whether the ORR proceeded through the 2e- or 4e- pathway. Although the total activity declined with very high anionomer loadings, the ORR appeared to proceed more through the 4e- pathway with increased anionomer content.

Porous Carbon-Hosted Atomically Dispersed Iron-Nitrogen Moiety as Enhanced Electrocatalysts for Oxygen Reduction Reaction in a Wide Range of pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Shaofang; Zhu, Chengzhou; Su, Dong

As one of the alternatives to replace precious metal catalysts, transition-metal–nitrogen–carbon (M–N–C) electrocatalysts have attracted great research interest due to their low cost and good catalytic activities. Despite nanostructured M–N–C catalysts can achieve good electrochemical perfor-mances, they are vulnerable to aggregation and insufficient catalytic sites upon continuous catalytic reaction. In this work, metal–organic frameworks derived porous single-atom electrocatalysts (SAEs) were successfully prepared by simple pyrolysis procedure without any further posttreatment. Combining the X-ray absorption near-edge spectroscopy and electrochemical measure-ments, the SAEs have been identified with superior oxygen reduction reaction (ORR) activity and stability compared with Pt/C catalysts in alkaline condition.more » More impressively, the SAEs also show excellent ORR electrocatalytic perfor-mance in both acid and neutral media. This study of nonprecious catalysts provides new insights on nanoengineering catalytically active sites and porous structures for nonprecious metal ORR catalysis in a wide range of pH.« less

Porous VOxNy nanoribbons supported on CNTs as efficient and stable non-noble electrocatalysts for the oxygen reduction reaction

PubMed Central

Huang, K.; Bi, K.; Lu, Y. K.; Zhang, R.; Liu, J.; Wang, W. J.; Tang, H. L.; Wang, Y. G.; Lei, M.

2015-01-01

Novel nanocomposites of carbon nanotubes supported porous VOxNy nonoribbons (VOxNy-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air. Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VOxNy-CNTs. Inspiringly, the results indicate that VOxNy-CNTs catalyst exhibits a 0.4 mA/cm2 larger diffusion-limited current density, a 0.10  V smaller onset potential value, a 10.73% less of ORR current decay and an excellent methanol-tolerance compared with commercial Pt/C catalyst. Therefore, we have reasonable grounds to believe that this new VOxNy-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells. PMID:26616719

Retrospective Evaluation of Hairy Cell Leukemia Patients Treated with Three Different First-Line Treatment Modalities in the Last Two Decades: A Single-Center Experience.

PubMed

Öngören, Şeniz; Eşkazan, Ahmet Emre; Berk, Selin; Elverdi, Tuğrul; Salihoğlu, Ayşe; Ar, Muhlis Cem; Başlar, Zafer; Aydın, Yıldız; Tüzüner, Nükhet; Soysal, Teoman

2017-12-01

In this study, we retrospectively analyzed the clinical outcome, treatment responses, infectious complications, and survival rates of 71 hairy cell leukemia (HCL) cases. Sixty-seven patients received a first-line treatment and 2-chlorodeoxyadenosine (cladribine-2-CdA) was administered in 31 cases, 19 patients received interferon-alpha (INF-α), splenectomy was performed in 16 cases, and rituximab was used in one. Although the highest overall response rate (ORR) was observed in patients receiving 2-CdA upfront, ORRs were comparable in the 2-CdA, INF-α, and splenectomy subgroups. Relapse rates were significantly lower in patients who received first-line 2-CdA. The progression-free survival (PFS) rate with 2-CdA was significantly higher than in patients with INF-α and splenectomy, but we found similar overall survival rates with all three upfront treatment modalities. Infections including tuberculosis were a major problem. Although purine analogues have improved the ORRs and PFS, there is still much progress to make with regard to overall survival and relapsed/refractory disease in patients with HCL.

Experimental identification of the active sites in pyrolyzed carbon-supported cobalt-polypyrrole-4-toluenesulfinic acid as electrocatalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Sha, Hao-Dong; Yuan, Xianxia; Li, Lin; Ma, Zhong; Ma, Zi-Feng; Zhang, Lei; Zhang, Jiujun

2014-06-01

A series of carbon supported cobalt-polypyrrole-4-toluenesulfinic acid have been pyrolyzed in an argon atmosphere at 800 °C, then structurally characterized and electrochemically evaluated as oxygen reduction reaction (ORR) catalysts in aqueous 0.5 M sulfuric acid. The structures are cobalt bonded to nitrogen species (Co-Nx) along with metallic cobalt and cobalt oxide. When the cobalt loading in the compound is less than 1.0 wt%, the predominate form is Co-Nx, when the loading is higher than 1.0 wt%, metallic Co and Co oxide particles co-exist with the Co-Nx compound. At a Co loading of ∼1.0 wt%, the catalyst gives the best ORR activity. Both metallic Co and Co oxide are not active for catalyzing ORR, and block the catalytically active Co-Nx species from the surface and reduce the catalytic activity since the diffusion limiting current density on a rotating disk electrode (RDE) increases when the electrode blocking agents are washed away with acid.

Porous VOxNy nanoribbons supported on CNTs as efficient and stable non-noble electrocatalysts for the oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Huang, K.; Bi, K.; Lu, Y. K.; Zhang, R.; Liu, J.; Wang, W. J.; Tang, H. L.; Wang, Y. G.; Lei, M.

2015-11-01

Novel nanocomposites of carbon nanotubes supported porous VOxNy nonoribbons (VOxNy-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air. Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VOxNy-CNTs. Inspiringly, the results indicate that VOxNy-CNTs catalyst exhibits a 0.4 mA/cm2 larger diffusion-limited current density, a 0.10  V smaller onset potential value, a 10.73% less of ORR current decay and an excellent methanol-tolerance compared with commercial Pt/C catalyst. Therefore, we have reasonable grounds to believe that this new VOxNy-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells.

Porous VO(x)N(y) nanoribbons supported on CNTs as efficient and stable non-noble electrocatalysts for the oxygen reduction reaction.

PubMed

Huang, K; Bi, K; Lu, Y K; Zhang, R; Liu, J; Wang, W J; Tang, H L; Wang, Y G; Lei, M

2015-11-30

Novel nanocomposites of carbon nanotubes supported porous VO(x)N(y) nonoribbons (VO(x)N(y)-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air. Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VO(x)N(y)-CNTs. Inspiringly, the results indicate that VO(x)N(y)-CNTs catalyst exhibits a 0.4 mA/cm(2) larger diffusion-limited current density, a 0.10  V smaller onset potential value, a 10.73% less of ORR current decay and an excellent methanol-tolerance compared with commercial Pt/C catalyst. Therefore, we have reasonable grounds to believe that this new VO(x)N(y)-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells.

Porous Carbon-Hosted Atomically Dispersed Iron–Nitrogen Moiety as Enhanced Electrocatalysts for Oxygen Reduction Reaction in a Wide Range of pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Shaofang; Zhu, Chengzhou; Su, Dong

2018-02-01

As one of the alternatives to replace precious metal catalysts, transition-metal–nitrogen–carbon (M–N–C) electrocatalysts have attracted great research interest due to their low cost and good catalytic activities. Despite nanostructured M–N–C catalysts can achieve good electrochemical perfor-mances, they are vulnerable to aggregation and insufficient catalytic sites upon continuous catalytic reaction. In this work, metal–organic frameworks derived porous single-atom electrocatalysts (SAEs) were successfully prepared by simple pyrolysis procedure without any further posttreatment. Combining the X-ray absorption near-edge spectroscopy and electrochemical measure-ments, the SAEs have been identified with superior oxygen reduction reaction (ORR) activity and stability compared with Pt/C catalysts in alkaline condition.more » More impressively, the SAEs also show excellent ORR electrocatalytic perfor-mance in both acid and neutral media. This study of nonprecious catalysts provides new insights on nanoengineering catalytically active sites and porous structures for nonprecious metal ORR catalysis in a wide range of pH.« less

One-pot synthesis of transition metal ion-chelating ordered mesoporous carbon/carbon nanotube composites for active and durable fuel cell catalysts

NASA Astrophysics Data System (ADS)

Dombrovskis, Johanna K.; Palmqvist, Anders E. C.

2017-07-01

Development of non-precious metal catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells with high activity and durability and with optimal water management properties is of outmost technological importance and highly challenging. Here we study the possibilities offered through judicious selection of small molecular precursors used for the formation of ordered mesoporous carbon-based non-precious metal ORR catalysts. By combining two complementary precursors, we present a one-pot synthesis that leads to a composite material consisting of transition metal ion-chelating ordered mesoporous carbon and multi-walled carbon nanotubes (TM-OMC/CNT). The resulting composite materials show high specific surface areas and a carbon structure that exhibits graphitic signatures. The synthesis procedure allows for tuning of the carbon structure, the surface area, the pore volume and the ratio of the two components of the composite. The TM-OMC/CNT composites were processed into membrane electrode assemblies and evaluated in single cell fuel cell measurements where they showed a combination of good ORR activity and very high durability.

Rapid room-temperature synthesis of nanocrystalline spinels as oxygen reduction and evolution electrocatalysts.

PubMed

Cheng, Fangyi; Shen, Jian; Peng, Bo; Pan, Yuede; Tao, Zhanliang; Chen, Jun

2011-01-01

Spinels can serve as alternative low-cost bifunctional electrocatalysts for oxygen reduction/evolution reactions (ORR/OER), which are the key barriers in various electrochemical devices such as metal-air batteries, fuel cells and electrolysers. However, conventional ceramic synthesis of crystalline spinels requires an elevated temperature, complicated procedures and prolonged heating time, and the resulting product exhibits limited electrocatalytic performance. It has been challenging to develop energy-saving, facile and rapid synthetic methodologies for highly active spinels. In this Article, we report the synthesis of nanocrystalline M(x)Mn(3-x)O(4) (M = divalent metals) spinels under ambient conditions and their electrocatalytic application. We show rapid and selective formation of tetragonal or cubic M(x)Mn(3-x)O(4) from the reduction of amorphous MnO(2) in aqueous M(2+) solution. The prepared Co(x)Mn(3-x)O(4) nanoparticles manifest considerable catalytic activity towards the ORR/OER as a result of their high surface areas and abundant defects. The newly discovered phase-dependent electrocatalytic ORR/OER characteristics of Co-Mn-O spinels are also interpreted by experiment and first-principle theoretical studies.

Critical role of intercalated water for electrocatalytically active nitrogen-doped graphitic systems

DOE PAGES

Martinez, Ulises; Dumont, Joseph H.; Holby, Edward F.; ...

2016-03-18

Graphitic materials are very essential in energy conversion and storage because of their excellent chemical and electrical properties. The strategy for obtaining functional graphitic materials involves graphite oxidation and subsequent dissolution in aqueous media, forming graphene-oxide nanosheets (GNs). Restacked GNs contain substantial intercalated water that can react with heteroatom dopants or the graphene lattice during reduction. We demonstrate that removal of intercalated water using simple solvent treatments causes significant structural reorganization, substantially affecting the oxygen reduction reaction (ORR) activity and stability of nitrogen-doped graphitic systems. Amid contrasting reports describing the ORR activity of GN-based catalysts in alkaline electrolytes, we demonstratemore » superior activity in an acidic electrolyte with an onset potential of ~0.9 V, a half-wave potential (E ½) of 0.71 V, and a selectivity for four-electron reduction of >95%. Finally and further, durability testing showed E ½ retention >95% in N 2- and O 2-saturated solutions after 2000 cycles, demonstrating the highest ORR activity and stability reported to date for GN-based electrocatalysts in acidic media.« less

Oxygen Reduction Reaction Affected by Sulfate-Reducing Bacteria: Different Roles of Bacterial Cells and Metabolites.

PubMed

Wu, Jiajia; Liu, Huaiqun; Wang, Peng; Zhang, Dun; Sun, Yan; Li, Ee

2017-09-01

Sulfate-reducing bacteria (SRB) were found to be capable of tolerating a certain amount of oxygen (O 2 ), but how they affect oxygen reduction reaction (ORR) has not been clear. The present work investigated the impact of SRB on ORR in 3.5 wt% sodium chloride solution with the cyclic voltammetry method. The addition of SRB culture solution hampered both the reduction of O 2 to superoxide (O 2 ·- ) and hydrogen peroxide (H 2 O 2 ) to water (H 2 O), and the influence of SRB metabolites was much larger than that of bacterial cells. Sulfide and extracellular polymeric substances (EPS), typical inorganic and organic metabolic products, had great impact on ORR. Sulfide played an important role in the decrease of cathodic current for H 2 O 2 reduction due to its hydrolysis and chemical reaction activity with H 2 O 2 . EPS were sticky, easy to adsorb on the electrode surface and abundant in functional groups, which hindered the transformation of O 2 into O 2 ·- and favored the reduction of H 2 O 2 to H 2 O.

Tailored Combination of Low Dimensional Catalysts for Efficient Oxygen Reduction and Evolution in Li-O2 Batteries.

PubMed

Yoon, Ki Ro; Kim, Dae Sik; Ryu, Won-Hee; Song, Sung Ho; Youn, Doo-Young; Jung, Ji-Won; Jeon, Seokwoo; Park, Yong Joon; Kim, Il-Doo

2016-08-23

The development of efficient bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is a key issue pertaining high performance Li-O2 batteries. Here, we propose a heterogeneous electrocatalyst consisting of LaMnO3 nanofibers (NFs) functionalized with RuO2 nanoparticles (NPs) and non-oxidized graphene nanoflakes (GNFs). The Li-O2 cell employing the tailored catalysts delivers an excellent electrochemical performance, affording significantly reduced discharge/charge voltage gaps (1.0 V at 400 mA g(-1) ), and superior cyclability for over 320 cycles. The outstanding performance arises from (1) the networked LaMnO3 NFs providing ORR/OER sites without severe aggregation, (2) the synergistic coupling of RuO2 NPs for further improving the OER activity and the electrical conductivity on the surface of the LaMnO3 NFs, and (3) the use of GNFs providing a fast electronic pathway as well as improved ORR kinetics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Clinical observation of icotinib hydrochloride in first-line therapy for pulmonary adenocarcinoma].

PubMed

Yang, Xinjie; Zhang, Hui; Qin, Na; Li, Xi; Nong, Jingying; Lv, Jialin; Wu, Yuhua; Zhang, Quan; Zhang, Shucai

2013-07-01

It has been proven that icotinib hydrochloride, as a molecule targeted drug, can be safely and efficiently used to treat advanced non-small cell lung cancer (NSCLC) for second-line or third-line. This research was aimed to investigate the efficacy and toxicity of icotinib hydrochloride as the first-line therapy for pulmonary adenocarcinoma. Among the 56 patients, the tumor objective response rate (ORR) and disease control rate (DCR) was 46.4% (26/56) and 78.6% (46/56), respectively. Among the 20 patients with EGFR analyses, 18 patients were positive for a mutation, ORR was 66.7% (12/18), DCR was 94.4% (17/18) respectively. The ORR with no history of smoke. EGFR positive mutation and appearance of rash were significantly higher than those with smoker, wild type EGFR, no information about EGFR and no appearance of rash (P<0.05). The most common drug-related adverse events were mild skin rash (28.5%) and diarrhea (12%). Single agent treatment with icotinib hydrochloride is effective and tolerable in first-line therapy for pulmonary adenocarcinoma, especially with EGFR mutation.

The Device Design of a Rural Domestic Sewage Treatment Performance

NASA Astrophysics Data System (ADS)

Liu, Zuhan; Wang, Lili; Deng, Chengzhi

2017-10-01

A kind of device for removing pollutant from rural domestic sewage isstudied in this paper, which belongs to the field of sewage treatment technology. The device include anaerobic pool, aerobiotic pool and aerating apparatus. Specifically, the aerobiotic pool is a sealed rectangular body with a rectangular groove on its top cover. The fixed wall is established on one side of the rectangular groove, and the wall is located in the middle of the top cover. The anaerobic pool is opposite to the fixed wall. And there is a aerating apparatusbetween the anaerobic pool and fixed wall, and the apparatus is situated right above the rectangular groove. The design is simple in structure and low in manufacturing cost. The biochemical ratio to the sewage could be improved through the anaerobic pool, and then the sewage is sufficiently aerated by means of natural ventilation and height of water. Theaerated sewage enter into aerobiotic pool, and then the organic matter is degraded into Carbon Dioxide and water under the action of aerobic bacteria, of which function is that the ammonia nitrogen is oxidized into nitrate and nitrite. The water that is far from the aerating apparatus inside of the aerobiotic pool enters into oxygen-deficient environment, and the nitrate is converted into nitrogen. After the effluent is checked qualified, the water is discharged into the drainage ditch or utilized for irrigation.

Impact and quantification of the sources of error in DNA pooling designs.

PubMed

Jawaid, A; Sham, P

2009-01-01

The analysis of genome wide variation offers the possibility of unravelling the genes involved in the pathogenesis of disease. Genome wide association studies are also particularly useful for identifying and validating targets for therapeutic intervention as well as for detecting markers for drug efficacy and side effects. The cost of such large-scale genetic association studies may be reduced substantially by the analysis of pooled DNA from multiple individuals. However, experimental errors inherent in pooling studies lead to a potential increase in the false positive rate and a loss in power compared to individual genotyping. Here we quantify various sources of experimental error using empirical data from typical pooling experiments and corresponding individual genotyping counts using two statistical methods. We provide analytical formulas for calculating these different errors in the absence of complete information, such as replicate pool formation, and for adjusting for the errors in the statistical analysis. We demonstrate that DNA pooling has the potential of estimating allele frequencies accurately, and adjusting the pooled allele frequency estimates for differential allelic amplification considerably improves accuracy. Estimates of the components of error show that differential allelic amplification is the most important contributor to the error variance in absolute allele frequency estimation, followed by allele frequency measurement and pool formation errors. Our results emphasise the importance of minimising experimental errors and obtaining correct error estimates in genetic association studies.

High air volume to low liquid volume aerosol collector

DOEpatents

Masquelier, Donald A.; Milanovich, Fred P.; Willeke, Klaus

2003-01-01

A high air volume to low liquid volume aerosol collector. A high volume flow of aerosol particles is drawn into an annular, centripetal slot in a collector which directs the aerosol flow into a small volume of liquid pool contained is a lower center section of the collector. The annular jet of air impinges into the liquid, imbedding initially airborne particles in the liquid. The liquid in the pool continuously circulates in the lower section of the collector by moving to the center line, then upwardly, and through assistance by a rotating deflector plate passes back into the liquid at the outer area adjacent the impinging air jet which passes upwardly through the liquid pool and through a hollow center of the collector, and is discharged via a side outlet opening. Any liquid droplets escaping with the effluent air are captured by a rotating mist eliminator and moved back toward the liquid pool. The collector includes a sensor assembly for determining, controlling, and maintaining the level of the liquid pool, and includes a lower centrally located valve assembly connected to a liquid reservoir and to an analyzer for analyzing the particles which are impinged into the liquid pool.

Testing the effectiveness and the contribution of experimental supercharge (reversed) end-to-side nerve transfer.

PubMed

Nadi, Mustafa; Ramachandran, Sudheesh; Islam, Abir; Forden, Joanne; Guo, Gui Fang; Midha, Rajiv

2018-05-18

OBJECTIVE Supercharge end-to-side (SETS) transfer, also referred to as reverse end-to-side transfer, distal to severe nerve compression neuropathy or in-continuity nerve injury is gaining clinical popularity despite questions about its effectiveness. Here, the authors examined SETS distal to experimental neuroma in-continuity (NIC) injuries for efficacy in enhancing neuronal regeneration and functional outcome, and, for the first time, they definitively evaluated the degree of contribution of the native and donor motor neuron pools. METHODS This study was conducted in 2 phases. In phase I, rats (n = 35) were assigned to one of 5 groups for unilateral sciatic nerve surgeries: group 1, tibial NIC with distal peroneal-tibial SETS; group 2, tibial NIC without SETS; group 3, intact tibial and severed peroneal nerves; group 4, tibial transection with SETS; and group 5, severed tibial and peroneal nerves. Recovery was evaluated biweekly using electrophysiology and locomotion tasks. At the phase I end point, after retrograde labeling, the spinal cords were analyzed to assess the degree of neuronal regeneration. In phase II, 20 new animals underwent primary retrograde labeling of the tibial nerve, following which they were assigned to one of the following 3 groups: group 1, group 2, and group 4. Then, secondary retrograde labeling from the tibial nerve was performed at the study end point to quantify the native versus donor regenerated neuronal pool. RESULTS In phase I studies, a significantly increased neuronal regeneration in group 1 (SETS) compared with all other groups was observed, but with modest (nonsignificant) improvement in electrophysiological and behavioral outcomes. In phase II experiments, the authors discovered that secondary labeling in group 1 was predominantly contributed from the donor (peroneal) pool. Double-labeling counts were dramatically higher in group 2 than in group 1, suggestive of hampered regeneration from the native tibial motor neuron pool across the NIC segment in the presence of SETS. CONCLUSIONS SETS is indeed an effective strategy to enhance axonal regeneration, which is mainly contributed by the donor neuronal pool. Moreover, the presence of a distal SETS coaptation appears to negatively influence neuronal regeneration across the NIC segment. The clinical significance is that SETS should only employ synergistic donors, as the use of antagonistic donors can downgrade recovery.

Standards to prevent, detect, and respond to sexual abuse and sexual harassment involving unaccompanied children. Interim final rule (IFR).

PubMed

2014-12-24

This IFR proposes standards and procedures to prevent, detect, and respond to sexual abuse and sexual harassment involving unaccompanied children (UCs) in ORR's care provider facilities. DATES: This IFR is effective on December 24, 2014. ORR care provider facilities must be in compliance with this IFR by June 24, 2015 but encourages care provider facilities to be in compliance sooner, if possible. HHS will work with facilities to implement and enforce the standards contained in this rule. Comments on this IFR must be received on or before February 23, 2015.

Photoregenerative I−/I3− couple as a liquid cathode for proton exchange membrane fuel cell

PubMed Central

Liu, Zhen; Wang, Yadong; Ai, Xinping; Tu, Wenmao; Pan, Mu

2014-01-01

A photoassisted oxygen reduction reaction (ORR) through I−/I3− redox couple was investigated for proton exchange membrane (PEM) fuel cell cathode reaction. The I−/I3−-based liquid cathode was used to replace conventional oxygen cathode, and its discharge product I− was regenerated to I3− by photocatalytic oxidation with the participation of oxygen. This new and innovative approach may provide a strategy to eliminate the usage of challenging ORR electrocatalysts, resulting in an avenue for developing low-cost and high-efficiency PEM fuel cells. PMID:25348812

Bat Acoustic Survey Report for ORNL: Bat Species Distribution on the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCracken, Kitty; Giffen, Neil R.; Haines, Angelina

This report summarizes results of a three-year acoustic survey of bat species on the US Department of Energy (DOE) Oak Ridge Reservation (ORR) in Oak Ridge, Tennessee. The survey was implemented through the Oak Ridge National Laboratory (ORNL) Natural Resources Management Program and included researchers from the ORNL Environmental Sciences Division and ORNL Facilities and Operations Directorate, Tennessee Wildlife Resources Agency’s ORR wildlife manager, a student from Tennessee Technological University, and a technician contracted through Excel Corp. One hundred and twenty-six sites were surveyed reservation-wide using Wildlife Acoustics SM2+ Acoustic Bat Detectors.

Oak Ridge Reservation environmental report for 1992. Volume 1: Narrative

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koncinski, W.S.

The two volumes of this report present data and supporting narratives regarding the impact of the US Department of Energy`s (DOE`s) Oak Ridge Reservation (ORR) on its environs and the public during 1992. This Volume (Volume 1) includes all narrative descriptions, summaries, and conclusions and is intended to be a ``stand-alone`` report for the reader who does not want to review in detail all of the 1992 data for the ORR. Volume 2 includes the detailed data in formats that ensure all the environmental data are represented. Narratives are not included in Vol. 2.

CSBF Engineering Overview

NASA Astrophysics Data System (ADS)

Orr, Dwayne

CSBF Engineering Overview Dwayne Orr (Presenting Author) Columbia Scientific Balloon Facility, Palestine, Texas (USA) Dwayne.Orr@csbf.nasa.gov The Columbia Scientific Balloon Facility (CSBF) at Palestine, Texas provides operational and engineering support for the launch of NASA Scientific Balloons. Over the years with the support of the NASA Balloon Program Office, CSBF has developed unique flight systems with the focus of providing a highly reliable, cost effective medium for giving Scientist’s access to a near space environment. This paper will provide an overview of the CSBF flight systems with an emphasis on recent developments and plans for the future.

The prognostic and predictive value of excision repair cross-complementation group 1 (ERCC1) protein in 1288 patients with head and neck squamous cell carcinoma treated with platinum-based therapy: a meta-analysis.

PubMed

Bišof, Vesna; Zajc Petranović, Matea; Rakušić, Zoran; Samardžić, Kristina Ruža; Juretić, Antonio

2016-09-01

Excision repair cross-complementation group 1 (ERCC1) protein has been extensively investigated as a prognostic and predictive factor for platinum-based treatment in head and neck squamous cell carcinoma (HNSCC) but with inconsistent results. We performed the present meta-analysis to better elucidate this issue in advanced HNSCC. A literature search was conducted using the PubMed and Web of Science databases. The inclusion criteria were head and neck cancer patients with platinum-based treatment and evaluation of the correlation between ERCC1 expression and clinical outcomes [objective response rate (ORR), progression-free survival (PFS), and overall survival (OS), both unadjusted and adjusted estimates]. In high vs. low pooled analyses, high ERCC1 expression was associated with unfavorable OS [hazard ratio (HR) = 1.95, 95 % confidence interval (CI) 1.18-3.21, p = 0.009], PFS (HR = 2.39, 95 % CI 1.74-3.28, p = 0.000) and ORR (odds ratio = 0.48, 95 % CI 0.23-0.98, p = 0.044). In the subgroup analysis of adjusted OS estimates, ERCC1 was a predictor of shorter survival in Asians (HR = 3.13, 95 % CI 2.09-4.70, p = 0.000) and Caucasians (HR = 2.02, 95 % CI 1.32-3.07, p = 0.001) but of longer survival in South Americans (HR = 0.17, 95 % CI 0.07-0.40, p = 0.000). Immunohistochemistry proved to be of predictive value irrespective of used antibody (p = 0.009). In the stratified analysis according to the tumor site, ERCC1 expression was associated with OS in nasopharyngeal cancer (HR = 2.72, 95 % CI 1.79-4.13, p = 0.000). ERCC1 has a potential to become predictive and prognostic factor enabling treatment tailoring in HNSCC patients.

Nanostructured nonprecious metal catalysts for oxygen reduction reaction.

PubMed

Wu, Gang; Zelenay, Piotr

2013-08-20

Platinum-based catalysts represent a state of the art in the electrocatalysis of oxygen reduction reaction (ORR) from the point of view of their activity and durability in harnessing the chemical energy via direct electrochemical conversion. However, because platinum is both expensive and scarce, its widespread implementation in such clean energy applications is limited. Recent breakthroughs in the synthesis of high-performance nonprecious metal catalysts (NPMCs) make replacement of Pt in ORR electrocatalysts with earth-abundant elements, such as Fe, Co, N, and C, a realistic possibility. In this Account, we discuss how we can obtain highly promising M-N-C (M: Fe and/or Co) catalysts by simultaneously heat-treating precursors of nitrogen, carbon, and transition metals at 800-1000 °C. The activity and durability of resulting catalysts depend greatly on the selection of precursors and synthesis chemistry. In addition, they correlate quite well with the catalyst nanostructure. While chemists have presented no conclusive description of the active catalytic site for this class of NPMCs, they have developed a designed approach to making active and durable materials, focusing on the catalyst nanostructure. The approach consists of nitrogen doping, in situ carbon graphitization, and the usage of graphitic structures (possibly graphene and graphene oxides) as carbon precursors. Various forms of nitrogen, particularly pyridinic and quaternary, can act as n-type carbon dopants in the M-N-C catalysts, assisting in the formation of disordered carbon nanostructures and donating electrons to the carbon. The CNx structures are likely a crucial part of the ORR active site(s). Noteworthy, the ORR activity is not necessarily governed by the amount of nitrogen, but by how the nitrogen is incorporated into the nanostructures. Apart from the possibility of a direct participation in the active site, the transition metal often plays an important role in the in situ formation of various carbon nanostructures by catalyzing the decomposition of the nitrogen/carbon precursor. We can control the formation of different nanostructures during the synthesis of M-N-C catalysts. For example, in situ formed nitrogen-doped graphene-sheets can only be derived from polyaniline (PANI), probably due to structural similarities between the aromatic structures of PANI and graphene. Highly-graphitized carbon nanostructures may serve as a matrix for the formation of ORR-active groups with improved catalytic activity and durability, containing nitrogen and most probably also metal atoms. In the future, we will likely focus NPMC synthesis approaches on precise control of interactions between precursors of the metal and carbon/nitrogen during the heat treatment. The main purposes will be to maximize the number of active sites, optimize nitrogen doping levels, and generate morphologies capable of hosting active and stable ORR sites.

Visualization of hump formation in high-speed gas metal arc welding

NASA Astrophysics Data System (ADS)

Wu, C. S.; Zhong, L. M.; Gao, J. Q.

2009-11-01

The hump bead is a typical weld defect observed in high-speed welding. Its occurrence limits the improvement of welding productivity. Visualization of hump formation during high-speed gas metal arc welding (GMAW) is helpful in the better understanding of the humping phenomena so that effective measures can be taken to suppress or decrease the tendency of hump formation and achieve higher productivity welding. In this study, an experimental system was developed to implement vision-based observation of the weld pool behavior during high-speed GMAW. Considering the weld pool characteristics in high-speed welding, a narrow band-pass and neutral density filter was equipped for the CCD camera, the suitable exposure time was selected and side view orientation of the CCD camera was employed. The events that took place at the rear portion of the weld pools were imaged during the welding processes with and without hump bead formation, respectively. It was found that the variation of the weld pool surface height and the solid-liquid interface at the pool trailing with time shows some useful information to judge whether the humping phenomenon occurs or not.

A Pooled Analysis on Crizotinib in Treating Chinese Patients with EML4-ALK Positive Non-small-cell Lung Cancer.

PubMed

Li, Yang; Huang, Xin-En

2015-01-01

This analysis was conducted to evaluate the efficacy and safety of crizotinib based regimens in treating Chinese patients with EML4-ALK positive non-small-cell lung cancer. Clinical studies evaluating the efficacy and safety of crizotinib based regimens on response and safety for Chinese patients with EML4-ALK positive non-small-cell lung cancer were identified by using a predefined search strategy. Pooled response rate (RR) of treatment were calculated. In crizotinib based regimens, 3 clinical studies which including 128 Chinese patients with EML4-ALK positive non-small-cell lung cancer and treated with crizotinib based regimen were considered eligible for inclusion. Pooled analysis suggested that, in all patients, the pooled RR was 59.3% (76/128) in crizotinib based regimens. ALT/AST mild visual disturbances, nausea, and vomiting were the main side effects. No treatment related death occurred in these crizotinib based treatments. This pooled analysis suggests that crizotinib based regimens are associated with good response rate and accepted toxicities in treating Chinese patients with EML4-ALK positive non-small-cell lung cancer.

Crossed reciprocal inhibition evoked by electrical stimulation of the lamprey spinal cord.

PubMed

Fagerstedt, P; Zelenin, P V; Deliagina, T G; Orlovsky, G N; Grillner, S

2000-09-01

Activation of a motoneuron pool is often accompanied by inhibition of the antagonistic pool through a system of reciprocal inhibition between the two parts of the neuronal network controlling the antagonistic pools. In the present study, we describe the activity of such a system in the isolated spinal cord of the lamprey, when a tonic motor output is evoked by extracellular stimulation (0.5-1 s train of pulses, 20 Hz) of either end of the spinal cord. With two electrodes symmetrically positioned in relation to the midline, stimulation with either of them separately elicited prolonged (1-5 s) ipsilateral ventral root activity. Activity could be abolished by stronger, simultaneously applied, stimulation of the contralateral side of the cord, suggesting that reciprocal inhibition between hemisegments operates when a tonic motor output is generated. Simultaneous stimulation of both sides of the spinal cord with a single electrode with a large tip (300-400 microm in diameter), positioned over the anatomical midline, elicited inconsistent right-side, leftside, or bilateral ventral root responses. A minor displacement (10-20 microm) to the left or right from the midline resulted in activation of ipsilateral motoneurons, whereas the contralateral motoneurons were silent. These findings indicate that a small asymmetry in the excitatory drive to the left and right spinal hemisegments can be further amplified by reciprocal inhibition between the hemisegments. Longitudinal splitting of the spinal cord along the midline resulted in reduced reciprocal inhibition between the hemisegments separated by the lesion. The reduction was proportional to the extent of the split. The inhibition was abolished when the split reached nine segments in length. From these experiments, the longitudinal distribution of the commissural axons responsible for inhibition of contralateral motor output could be estimated.

Facile Synthesis of Defect-Rich and S/N Co-Doped Graphene-Like Carbon Nanosheets as an Efficient Electrocatalyst for Primary and All-Solid-State Zn-Air Batteries.

PubMed

Zhang, Jian; Zhou, Huang; Zhu, Jiawei; Hu, Pei; Hang, Chao; Yang, Jinlong; Peng, Tao; Mu, Shichun; Huang, Yunhui

2017-07-26

Developing facile and low-cost porous graphene-based catalysts for highly efficient oxygen reduction reaction (ORR) remains an important matter for fuel cells. Here, a defect-enriched and dual heteroatom (S and N) doped hierarchically porous graphene-like carbon nanomaterial (D-S/N-GLC) was prepared by a simple and scalable strategy, and exhibits an outperformed ORR activity and stability as compared to commercial Pt/C catalyst in an alkaline condition (its half-wave potential is nearly 24 mV more positive than Pt/C). The excellent ORR performance of the catalyst can be attributed to the synergistic effect, which integrates the novel graphene-like architectures, 3D hierarchically porous structure, superhigh surface area, high content of active dopants, and abundant defective sites in D-S/N-GLC. As a result, the developed catalysts are used as the air electrode for primary and all-solid-state Zn-air batteries. The primary batteries demonstrate a higher peak power density of 252 mW cm -2 and high voltage of 1.32 and 1.24 V at discharge current densities of 5 and 20 mA cm -2 , respectively. Remarkably, the all-solid-state battery also exhibits a high peak power density of 81 mW cm -2 with good discharge performance. Moreover, such catalyst possesses a comparable ORR activity and higher stability than Pt/C in acidic condition. The present work not only provides a facile but cost-efficient strategy toward preparation of graphene-based materials, but also inspires an idea for promoting the electrocatalytic activity of carbon-based materials.

Enhanced Intrinsic Catalytic Activity of λ-MnO2 by Electrochemical Tuning and Oxygen Vacancy Generation.

PubMed

Lee, Sanghan; Nam, Gyutae; Sun, Jie; Lee, Jang-Soo; Lee, Hyun-Wook; Chen, Wei; Cho, Jaephil; Cui, Yi

2016-07-18

Chemically prepared λ-MnO2 has not been intensively studied as a material for metal-air batteries, fuel cells, or supercapacitors because of their relatively poor electrochemical properties compared to α- and δ-MnO2 . Herein, through the electrochemical removal of lithium from LiMn2 O4 , highly crystalline λ-MnO2 was prepared as an efficient electrocatalyst for the oxygen reduction reaction (ORR). The ORR activity of the material was further improved by introducing oxygen vacancies (OVs) that could be achieved by increasing the calcination temperature during LiMn2 O4 synthesis; a concentration of oxygen vacancies in LiMn2 O4 could be characterized by its voltage profile as the cathode in a lithiun-metal half-cell. λ-MnO2-z prepared with the highest OV exhibited the highest diffusion-limited ORR current (5.5 mA cm(-2) ) among a series of λ-MnO2-z electrocatalysts. Furthermore, the number of transferred electrons (n) involved in the ORR was >3.8, indicating a dominant quasi-4-electron pathway. Interestingly, the catalytic performances of the samples were not a function of their surface areas, and instead depended on the concentration of OVs, indicating enhancement in the intrinsic catalytic activity of λ-MnO2 by the generation of OVs. This study demonstrates that differences in the electrochemical behavior of λ-MnO2 depend on the preparation method and provides a mechanism for a unique catalytic behavior of cubic λ-MnO2 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ZIF-67 incorporated with carbon derived from pomelo peels: A highly efficient bifunctional catalyst for oxygen reduction/evolution reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hao; Yin, Feng-Xiang; Chen, Biao-Hua

Developing carbon catalyst materials using natural, abundant and renewable resources as precursors plays an increasingly important role in clean energy generation and environmental protection. In this work, N-doped pomelo-peel-derived carbon (NPC) materials were prepared using a widely available food waste-pomelo peels and melamine. The synthetic NPC exhibits well-defined porosities and a highly doped-N content (e.g. 6.38 at% for NPC-2), therefore affords excellent oxygen reduction reaction (ORR) catalytic activities in alkaline electrolytes. NPC was further integrated with ZIF-67 to form ZIF-67@NPC hybrids through solvothermal reactions. The hybrid catalysts show substantially enhanced ORR catalytic activities comparable to that of commercial 20 wamore » Pt/C. Furthermore, the catalysts also exhibit excellent oxygen evolution reaction (OER) catalytic activities. Among all prepared ZIF-67@NPC hybrids, the optimal composition with ZIF-67 to NPC ratio of 2:1 exhibits the best ORR and OER bifunctional catalytic performance and the smallest Delta E (E-OER@10 mA cm(-2)-E-ORR@-1 mA cm(-2)) value of 0.79 V. The catalyst also demonstrated desirable 4-electron transfer pathways and superior catalytic stabilities. The Co-N-4 in ZIF-67, electrochemical active surface area, and the strong interactions between ZIF-67 and NPC are attributed as the main contributors to the bifunctional catalytic activities. These factors act synergistically, resulting in substantially enhanced bifunctional catalytic activities and stabilities; consequently, this hybrid catalyst is among the best of the reported bifunctional electrocatalysts and is promising for use in metal-air batteries and fuel cells. (C) 2016 Elsevier B.V. All rights reserved.« less

Mechanisms of the oxygen reduction reaction on B- and/or N-doped carbon nanomaterials with curvature and edge effects.

PubMed

Zou, Xiaolong; Wang, Luqing; Yakobson, Boris I

2018-01-18

Despite recent increased research interest in hetero-atom (B and/or N) doping effects on the oxygen reduction reaction (ORR) performance of carbon nanomaterials, microscopic understanding of active catalytic sites and effects of B and/or N doping has not been conclusively reached. Here, through comparative first-principles simulations between BN codoping and isolated B or N doping in both graphene nanoribbons (GNRs) and carbon nanotubes (CNTs), we not only identify active sites in these doped carbon nanomaterials, but elucidate the underlying mechanism of ORR processes. While the distortion of C-C bonds in CNTs leads to strong binding of O 2 , spin density distribution along the edges plays a key role in enhancing the adsorption strength of O 2 on GNRs. The effective adsorption of O 2 facilitates the following elementary reduction reactions. Based on thermodynamic analyses, O 2 adsorption as well as the electron and proton transfer to O atom are identified as key rate-determining steps. For CNTs, a good linear scaling is found between the adsorption energies of key intermediate products and that of atomic O, and thus the latter serves as a good descriptor for ORR activities. Further, N-doped high-quality CNTs are shown to exhibit best performance. For GNRs, due to edge effects, the linear relationship is broken, which promotes the catalytic activities in the BN codoping case. These findings resolve the long-standing controversy on the synergetic effects of B and N codoping, which deepens our understanding of the reaction mechanism. This work might further facilitate the optimization of the doping strategies for high-efficiency carbon-based ORR catalysts.

Reactive template synthesis of nitrogen-doped graphene-like carbon nanosheets derived from hydroxypropyl methylcellulose and dicyandiamide as efficient oxygen reduction electrocatalysts

NASA Astrophysics Data System (ADS)

Hu, Chun; Zhou, Yao; Ma, Ruguang; Liu, Qian; Wang, Jiacheng

2017-03-01

Oxygen reduction reaction (ORR) plays a dominant role in proton exchange membrane fuel cells (PEMFCs). Thus, the design and preparation of efficient ORR electrocatalysts is of high importance. In this work, we successfully prepared a series of nitrogen-doped graphene-like carbon nanosheets (NCNSs) with large pore volumes of up to 1.244 cm3 g-1 and high level of N dopants (5.3-6.8 at%) via a one-step, in-situ reactive template strategy by co-pyrolysis of hydroxypropyl methylcellulose (HPMC) and dicyandiamide (DICY) as the precursors at 1000 °C. The DICY-derived graphitic carbon nitride (g-C3N4) nanosheets could act as the hard template for the confined growth of 2D carbon nanosheets, and the further increase in the pyrolysis temperature could directly remove off the g-C3N4 template by complete decomposition and simultaneously dope N atoms within the carbon nanosheets. The pyridinic and graphitic nitrogen groups are dominant among various N functional groups in the NCNSs. The NCNS_1:10 prepared with the HPMC/DICY mass ratio of 1/10 can be used as the metal-free ORR electrocatalysts with optimal activity (onset potential: -0.1 V vs. SCE; limiting current density: 4.8 mA cm-2) in O2-saturated 0.1 M KOH electrolyte among the NCNSs. Moreover, the NCNS_1:10 demonstrates a dominant four-electron reduction process, as well as excellent long-term operation stability and outstanding methanol crossover resistance. The excellent ORR activity of the NCNS_1:10 should be mainly owing to high contents of pyridinic and graphitic N dopants, large pore volume, hierarchical structures, and microstructural defects.

Ga-Doped Pt-Ni Octahedral Nanoparticles as a Highly Active and Durable Electrocatalyst for Oxygen Reduction Reaction.

PubMed

Lim, JeongHoon; Shin, Hyeyoung; Kim, MinJoong; Lee, Hoin; Lee, Kug-Seung; Kwon, YongKeun; Song, DongHoon; Oh, SeKwon; Kim, Hyungjun; Cho, EunAe

2018-04-11

Bimetallic PtNi nanoparticles have been considered as a promising electrocatalyst for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) owing to their high catalytic activity. However, under typical fuel cell operating conditions, Ni atoms easily dissolve into the electrolyte, resulting in degradation of the catalyst and the membrane-electrode assembly (MEA). Here, we report gallium-doped PtNi octahedral nanoparticles on a carbon support (Ga-PtNi/C). The Ga-PtNi/C shows high ORR activity, marking an 11.7-fold improvement in the mass activity (1.24 A mg Pt -1 ) and a 17.3-fold improvement in the specific activity (2.53 mA cm -2 ) compared to the commercial Pt/C (0.106 A mg Pt -1 and 0.146 mA cm -2 ). Density functional theory calculations demonstrate that addition of Ga to octahedral PtNi can cause an increase in the oxygen intermediate binding energy, leading to the enhanced catalytic activity toward ORR. In a voltage-cycling test, the Ga-PtNi/C exhibits superior stability to PtNi/C and the commercial Pt/C, maintaining the initial Ni concentration and octahedral shape of the nanoparticles. Single cell using the Ga-PtNi/C exhibits higher initial performance and durability than those using the PtNi/C and the commercial Pt/C. The majority of the Ga-PtNi nanoparticles well maintain the octahedral shape without agglomeration after the single cell durability test (30,000 cycles). This work demonstrates that the octahedral Ga-PtNi/C can be utilized as a highly active and durable ORR catalyst in practical fuel cell applications.

Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies.

PubMed

Petkov, Valeri; Prasai, Binay; Shan, Shiyao; Ren, Yang; Wu, Jinfang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian

2016-05-19

Here we present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). In particular, using in operando high-energy X-ray diffraction (HE-XRD) we tracked the evolution of the atomic structure and activity of noble metal-transition metal (NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum.

Environmental data and analyses for the proposed management of spent nuclear fuel on the DOE Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Socolof, M.L.; Curtis, A.H.; Blasing, T.J.

1995-08-01

DOE needs to continue the safe and efficient management of SNF on ORR, based on the requirement for future SNF storage capacity and implementation of the ROD for the PEIS. DOE is proposing to implement the ROD through proper management of SNF on ORR, including the possible construction and operation of a dry cask storage facility. This report describes the potentially affected environment and analyzes impacts on various resources due to the proposed action. The information provided in this report is intended to support the Environmental Assessment being prepared for the proposed activities. Construction of the dry cask storage facilitymore » would result in minimal or no impacts on groundwater, surface water, and ecological resources. Contaminated soils excavated during construction would result in negligible risk to human health and to biota. Except for noise from trucks and equipment, operation of the dry cask storage facility would not be expected to have any impact on vegetation, wildlife, or rare plants or animals. Noise impacts would be minimal. Operation exposures to the average SNF storage facility worker would not exceed approximately 0.40 mSv/year (40 mrem/year). The off-site population dose within an 80-km (50-mile) radius of ORR from SNF operations would be less than 0.052 person-Sv/year (5.2 person-rem/year). Impacts from incident-free transportation on ORR would be less than 1.36 X 10{sup -4} occupational fatal cancers and 4.28 X 10{sup -6} public fatal cancers. Credible accident scenarios that would result in the greatest probable risks would cause less than one in a million cancer fatalities to workers and the public.« less

Optimal Ranking Regime Analysis of TreeFlow Dendrohydrological Reconstructions

NASA Astrophysics Data System (ADS)

Mauget, S. A.

2017-12-01

The Optimal Ranking Regime (ORR) method was used to identify 6-100 year time windows containing significant ranking sequences in 55 western U.S. streamflow reconstructions, and reconstructions of the level of the Great Salt Lake and San Francisco Bay salinity during 1500-2007. The method's ability to identify optimally significant and non-overlapping runs of low and high rankings allows it to re-express a reconstruction time series as a simplified sequence of regime segments marking intra- to multi-decadal (IMD) periods of low or high streamflow, lake level, or salinity. Those ORR sequences, referred to here as Z-lines, can be plotted to identify consistent regime patterns in the analysis of numerous reconstructions. The Z-lines for the 57 reconstructions evaluated here show a common pattern of IMD cycles of drought and pluvial periods during the late 16th and 17th centuries, a relatively dormant period during the 18th century, and the reappearance of alternating dry and wet IMD periods during the 19th and early 20th centuries. Although this pattern suggests the possibility of similarly active and inactive oceanic modes in the North Pacific and North Atlantic, such centennial-scale patterns are not evident in the ORR analyses of reconstructed Pacific Decadal Oscillation (PDO), El Niño-Southern Oscillation, and North Atlantic seas-surface temperature variation. But given the inconsistency in the analyses of four PDO reconstructions the possible role of centennial-scale oceanic mechanisms is uncertain. In future research the ORR method might be applied to climate reconstructions around the Pacific Basin to try to resolve this uncertainty. Given its ability to compare regime patterns in climate reconstructions derived using different methods and proxies, the method may also be used in future research to evaluate long-term regional temperature reconstructions.

Baseline Tumor Size Is an Independent Prognostic Factor for Overall Survival in Patients With Melanoma Treated With Pembrolizumab.

PubMed

Joseph, Richard W; Elassaiss-Schaap, Jeroen; Kefford, Richard F; Hwu, Wen-Jen; Wolchok, Jedd D; Joshua, Anthony Michael; Ribas, Antoni; Hodi, F Stephen; Hamid, Omid; Robert, Caroline; Daud, Adil I; Dronca, Roxana S; Hersey, Peter; Weber, Jeffrey S; Patnaik, Amita; de Alwis, Dinesh P; Perrone, Andrea M; Zhang, Jin; Kang, Soonmo Peter; Ebbinghaus, Scot W; Anderson, Keaven M; Gangadhar, Tara

2018-04-23

To assess the association of baseline tumor size (BTS) with other baseline clinical factors and outcomes in pembrolizumab-treated patients with advanced melanoma in KEYNOTE-001 (NCT01295827). BTS was quantified by adding the sum of the longest dimensions of all measurable baseline target lesions. BTS as a dichotomous and continuous variable was evaluated with other baseline factors using logistic regression for objective response rate (ORR) and Cox regression for overall survival (OS). Nominal P values with no multiplicity adjustment describe the strength of observed associations. Per central review by RECIST v1.1, 583 of 655 patients had baseline measurable disease and were included in this post hoc analysis. Median BTS was 10.2 cm (range, 1-89.5). Larger median BTS was associated with Eastern Cooperative Oncology Group performance status 1, elevated lactate dehydrogenase (LDH), stage M1c disease, and liver metastases (with or without any other sites) (all P ≤ 0.001). In univariate analyses, BTS below the median was associated with higher ORR (44% vs 23%; P < 0.001) and improved OS (hazard ratio, 0.38; P < 0.001). In multivariate analyses, BTS below the median remained an independent prognostic marker of OS (P < 0.001) but not ORR. In 459 patients with available tumor programmed death ligand 1 (PD-L1) expression, BTS below the median and PD-L1-positive tumors were independently associated with higher ORR and longer OS. BTS is associated with many other baseline clinical factors but is also independently prognostic of survival in pembrolizumab-treated patients with advanced melanoma. Copyright ©2018, American Association for Cancer Research.

Molecular predictors of outcome with gefitinib and docetaxel in previously treated non-small-cell lung cancer: data from the randomized phase III INTEREST trial.

PubMed

Douillard, Jean-Yves; Shepherd, Frances A; Hirsh, Vera; Mok, Tony; Socinski, Mark A; Gervais, Radj; Liao, Mei-Lin; Bischoff, Helge; Reck, Martin; Sellers, Mark V; Watkins, Claire L; Speake, Georgina; Armour, Alison A; Kim, Edward S

2010-02-10

PURPOSE In the phase III INTEREST trial, 1,466 pretreated patients with advanced non-small cell lung cancer (NSCLC) were randomly assigned to receive gefitinib or docetaxel. As a preplanned analysis, we prospectively analyzed available tumor biopsies to investigate the relationship between biomarkers and clinical outcomes. METHODS Biomarkers included epidermal growth factor receptor (EGFR) copy number by fluorescent in situ hybridization (374 assessable samples), EGFR protein expression by immunohistochemistry (n = 380), and EGFR (n = 297) and KRAS (n = 275) mutations. Results For all biomarker subgroups analyzed, survival was similar for gefitinib and docetaxel, with no statistically significant differences between treatments and no significant treatment by biomarker status interaction tests. EGFR mutation-positive patients had longer progression-free survival (PFS; hazard ratio [HR], 0.16; 95% CI, 0.05 to 0.49; P = .001) and higher objective response rate (ORR; 42.1% v 21.1%; P = .04), and patients with high EGFR copy number had higher ORR (13.0% v 7.4%; P = .04) with gefitinib versus docetaxel. CONCLUSION These biomarkers do not appear to be predictive factors for differential survival between gefitinib and docetaxel in this setting of previously treated patients; however, subsequent treatments may have influenced the survival results. For secondary end points of PFS and ORR, some advantages for gefitinib over docetaxel were seen in EGFR mutation-positive and high EGFR copy number patients. There was no statistically significant difference between gefitinib and docetaxel in biomarker-negative patients. This suggests gefitinib can provide similar overall survival to docetaxel in patients across a broad range of clinical subgroups and that EGFR biomarkers such as mutation status may additionally identify which patients are likely to gain greatest PFS and ORR benefit from gefitinib.

Self-assembled dopamine nanolayers wrapped carbon nanotubes as carbon-carbon bi-functional nanocatalyst for highly efficient oxygen reduction reaction and antiviral drug monitoring

NASA Astrophysics Data System (ADS)

Khalafallah, Diab; Akhtar, Naeem; Alothman, Othman Y.; Fouad, H.; Abdelrazek khalil, Khalil

2017-09-01

Oxygen reduction reaction (ORR) catalysts are the heart of eco-friendly energy resources particularly low temperature fuel cells. Although valuable efforts have been devoted to synthesize high performance catalysts for ORR, considerable challenges are extremely desirable in the development of energy technologies. Herein, we report a simple self-polymerization method to build a thin film of dopamine along the tubular nanostructures of multi-walled carbon nanotubes (CNT) in a weak alkaline solution. The dopamine@CNT hybrid (denoted as DA@CNT) reveals an enhanced electrocatalytic activity towards ORR with highly positive onset potential and cathodic current as a result of their outstanding features of longitudinal mesoporous structure, high surface area, and ornamentation of DA layers with nitrogen moieties, which enable fast electron transport and fully exposed electroactive sites. Impressively, the as-obtained hybrid afford remarkable electrochemical durability for prolonged test time of 60,000 s compared to benchmark Pt/C (20 wt%) catalyst. Furthermore, the developed DA@CNT electrode was successfully applied to access the quality of antiviral drug named Valacyclovir (VCR). The DA@CNT electrode shows enhanced sensing performance in terms of large linear range (3-75 nM), low limit of detection (2.55 nM) than CNT based electrode, indicating the effectiveness of the DA coating. Interestingly, the synergetic effect of nanostructured DA and CNT can significantly boost the electronic configuration and exposure level of active species for ORR and biomolecule recognition. Therefore, the existing carbon-based porous electrocatalyst may find numerous translational applications as attractive alternative to noble metals in polymer electrolyte membrane fuel cells and quality control assessment of pharmaceutical and therapeutic drugs.

Dermatux: phase IV trial of Cetuximab plus FOLFIRI in first-line metastatic colorectal cancer receiving a pre-defined skin care.

PubMed

Schimanski, Carl Christoph; Staib, Frank; Göhler, Thomas; Hebart, Holger; Heike, Michael; Neise, Michael; Rudi, Jochen; Geer, Thomas; Dingeldein, Gerrit; Lang, Claudia; Ehscheidt, Peter; Flohr, Thomas; Josten, Klaus Maria; Karthaus, Meinolf; Schmittel, Alexander; Wierecky, Jan; Boller, Emil; Indorf, Martin; Wörns, Marcus-Alexander; Galle, Peter R; Moehler, Markus

2017-06-01

Cetuximab-induced skin rash Gd3+ occurs in ≥16% patients (pts) (Heinemann et al., Lancet Oncol 15(10):1065-1075, 2014; Van Cutsem et al. J Clin Oncol 27(19):3117-25; 2009b). Survival, response, and toxicity parameters were re-evaluated under a pre-defined skin prophylaxis consistent of vitamin K1 ointment and oral doxycycline. This is a national, multicenter, phase 4, first-line mCRC (K-RAS wt) trial. Pts received irinotecan 180 mg/m² (d1), FA 400 mg/m² (d1), 5-FU 400 mg/m² (d1), 5-FU 2400 mg/m² (d1-2), and cetuximab [400 mg/m² (d1), and then 250 mg/m² qw], prophylactic 0.1% vitamin K1 ointment qd, and oral doxycycline 100 mg bid. 1-year PFS rate; secondary objectives: skin side-effects (grade, onset), objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) time, and overall survival (OS) time and safety. Twenty centers recruited 55 patients. Recruitment started Q1 2011 and ended Q3 2013 due to slow accrual. Characteristics were in line with CRYSTAL trial except for age and colonic location. 1-year PFS rate was 25.9%, mOS 21.8 months (m), and mPFS 8.5 m. ORR was 63.0%, DCR 77.8%. Rash Gd2+ occurred in 42.6% [median onset was 4.0 weeks (w)]; paronychia Gd2+ occurred in 22.2% (median onset 15.4w.); skin fissures Gd2+ occurred in 31.5% (median onset 19.9 weeks) 7% pts abandoned cetuximab treatment due to toxicity. Our data reveal encouraging improvements in skin reactions and their time to occurrence due to a pre-defined skin care.

Spatial variation in fish species richness of the upper Mississippi River system

USGS Publications Warehouse

Koel, T.M.

2004-01-01

Important natural environmental gradients, including the connectivity of off-channel aquatic habitats to the main-stem river, have been lost in many reaches of the upper Mississippi River system, and an understanding of the consequences of this isolation is lacking in regard to native fish communities. The objectives of this study were to describe patterns of fish species richness, evenness, and diversity among representative habitats and river reaches and to examine the relationship between fish species richness and habitat diversity. Each year (1994-1999) fish communities of main-channel borders (MCB), side channel borders (SCB), and contiguous backwater shorelines (BWS) were sampled using boat-mounted electrofishing, mini-fyke-nets, tyke nets, hoop nets, and seines at a standardized number of sites. A total of 0.65 million fish were collected, representing 106 species from upper Mississippi River Pools 4, 8, 13, and 26; the open (unimpounded) river reach; and the La Grange Reach of the Illinois River. Within pools, species richness based on rarefaction differed significantly among habitats and was highest in BWS and lowest in MCB (P < 0.0001). At the reach scale, Pools 4, 8, and 13 consistently had the highest species richness and Pool 26, the open-river reach, and the La Grange Reach were significantly lower (P < 0.0001). Species evenness and diversity indices showed similar trends. The relationship between native fish species richness and habitat diversity was highly significant (r(2) = 0.85; P = 0.0091). These results support efforts aimed at the conservation and enhancement of connected side channels and backwaters. Although constrained by dams, pools with high native species richness could serve as a relative reference. The remnants of natural riverine dynamics that remain in these reaches should be preserved and enhanced; conditions could be used to guide restoration activities in more degraded reaches.

Testing and checkout experiences in the National Transonic Facility since becoming operational

NASA Technical Reports Server (NTRS)

Bruce, W. E., Jr.; Gloss, B. B.; Mckinney, L. W.

1988-01-01

The U.S. National Transonic Facility, constructed by NASA to meet the national needs for High Reynolds Number Testing, has been operational in a checkout and test mode since the operational readiness review (ORR) in late 1984. During this time, there have been problems centered around the effect of large temperature excursions on the mechanical movement of large components, the reliable performance of instrumentation systems, and an unexpected moisture problem with dry insulation. The more significant efforts since the ORR are reviewed and NTF status concerning hardware, instrumentation and process controls systems, operating constraints imposed by the cryogenic environment, and data quality and process controls is summarized.

On the solution of two-point linear differential eigenvalue problems. [numerical technique with application to Orr-Sommerfeld equation

NASA Technical Reports Server (NTRS)

Antar, B. N.

1976-01-01

A numerical technique is presented for locating the eigenvalues of two point linear differential eigenvalue problems. The technique is designed to search for complex eigenvalues belonging to complex operators. With this method, any domain of the complex eigenvalue plane could be scanned and the eigenvalues within it, if any, located. For an application of the method, the eigenvalues of the Orr-Sommerfeld equation of the plane Poiseuille flow are determined within a specified portion of the c-plane. The eigenvalues for alpha = 1 and R = 10,000 are tabulated and compared for accuracy with existing solutions.

Three dimensional metal/N-doped nanoplate carbon catalysts for oxygen reduction, the reason for using a layered nanoreactor.

PubMed

Yeganeh Ghotbi, Mohammad; Javanmard, Arash; Soleimani, Hassan

2018-02-21

A layered nanoreactor (zinc hydroxide gallate/nitrate nanohybrid) has been designed as a nano-vessel to confine the gallate/nitrate reaction inside zinc hydroxide layers for production of metal/nitrogen-doped carbon catalysts. Metals (Fe 2+ , Co 2+ and Ni 2+ ) doped and bare zinc hydroxide nitrates (ZHN) were synthesized as the α-phase hydroxide hosts. By an incomplete ion-exchange process, nitrate anions between the layers of the hosts were then partially replaced by the gallate anions to produce the layered nanoreactors. Under heat-treatment, the reaction between the remaining un-exchanged nitrate anions and the organic moiety inside the basal spacing of each nanohybrid plate resulted in obtaining highly porous 3D metal/nitrogen-doped carbon nanosheets. These catalysts were then used as extremely efficient electrocatalysts for catalyzing oxygen reduction reaction (ORR). This study is intended to show the way to get maximum electrocatalytic activity of the metal/N-doped carbon catalysts toward the ORR. This exceptionally high ORR performance originates from the increased available surface, the best pore size range and the uniform distribution of the active sites in the produced catalysts, all provided by the use of new idea of the layered nanoreactor.

Magnetic N-Enriched Fe3C/Graphitic Carbon instead of Pt as an Electrocatalyst for the Oxygen Reduction Reaction.

PubMed

Wang, Xiaobai; Zhang, Peng; Wang, Wei; Lei, Xiang; Yang, Hua

2016-03-24

A series of Fe3C/C-Nx nanoparticles (NPs) with different nitrogen content are prepared by a simple one-pot route. In the synthetic procedure, aniline and acetonitrile are simultaneously used as the carbon and nitrogen source. The effect of calcination temperature on the structural and functional properties of the materials is investigated. Magnetic measurement shows that the sample prepared at 800 °C (Fe3 C/C-N800 NPs) possesses the highest Ms value of 77.2 emu g(-1). On testing as oxygen reduction reaction (ORR) catalysts, the sample prepared at 750 °C (Fe3C/C-N750 NPs) shows the best ORR performance among the series, with a more positive onset potential (+0.99 V vs. RHE), higher selectivity (number of electron transfer n≈3.93), longer durability, and stronger tolerance against methanol crossover than commercial Pt/C catalysts in a 0.1 m KOH solution. Moreover, in acidic solution, the excellent ORR activity and stability are also exhibited. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Porous Carbon-Hosted Atomically Dispersed Iron-Nitrogen Moiety as Enhanced Electrocatalysts for Oxygen Reduction Reaction in a Wide Range of pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Shaofang; Zhu, Chengzhou; Su, Dong

As one of the alternatives to replace precious metal catalysts, transition metal-nitrogen-carbon (M-N-C) electrocatalysts have attracted great research interest due to their low cost and good catalytic activities. Despite nanostructured M-N-C catalysts can achieve good electrochemical performances, they are vulnerable to aggregation and insufficient catalytic sites upon continuous catalytic reaction. Thus, M-N-C’s stability and selectivity have not been comparable to their noble metal counterparts. In this work, metal-organic frameworks (MOFs)-derived porous single-atom electrocatalysts (SAEs) were successfully prepared by simple pyrolysis procedure without any further post-treatment. Combining the X-ray absorption near-edge spectroscopy (XANES) and electrochemical measurements, the SAEs have been identifiedmore » with superior ORR activity and stability compared with Pt/C catalysts in alkaline condition. More impressively, the SAEs also show excellent ORR electrocatalytic performance in both acid and neutral media. Furthermore, this study of nonprecious catalysts provides new insights on nano-engineering catalytically active sites and porous structures for nonprecious metal ORR catalysis in a wide range of pH.« less

Notes from the field: hospitalizations for respiratory disease among unaccompanied children from Central America - multiple States, June-July 2014.

PubMed

Nyangoma, Edith N; Arriola, Carmen Sofia; Hagan, Jose; Socias, Christina; Tomczyk, Sara; Watkins, Louise Francois; Westercamp, Matthew; Kim, Curi

2014-08-15

During October 2013-June 2014, approximately 54,000 unaccompanied children, mostly from the Central American countries of El Salvador, Guatemala, and Honduras, were identified attempting entry into the United States from Mexico, exceeding numbers reported in previous years. Once identified in the United States, U.S. Customs and Border Protection, an agency of the U.S. Department of Homeland Security, processes the unaccompanied children and transfers them to the Office of Refugee Resettlement (ORR), an office of the Administration for Children and Families, U.S. Department of Health and Human Services. ORR cares for the children in shelters until they can be released to a sponsor, typically a parent or relative, who can care for the child while their immigration case is processed. In June 2014, in response to the increased number of unaccompanied children, U.S. Customs and Border Protection expanded operations to accommodate children at a processing center in Nogales, Arizona. ORR, together with the U.S. Department of Defense, opened additional large temporary shelters for the children at Lackland Air Force Base, Texas; U.S. Army Garrison Ft. Sill, Oklahoma; and Naval Base Ventura County, California.

Characteristics of tuneable optical filters using optical ring resonator with PCF resonance loop

NASA Astrophysics Data System (ADS)

Shalmashi, K.; Seraji, F. E.; Mersagh, M. R.

2012-05-01

A theoretical analysis of a tuneable optical filter is presented by proposing an optical ring resonator (ORR) using photonic crystal fiber (PCF) as the resonance loop. The influences of the characteristic parameters of the PCF on the filter response have been analyzed under steady-state condition of the ORR. It is shown that the tuneability of the filter is mainly achieved by changing the modulation frequency of the light signal applied to the resonator. The analyses have shown that the sharpness and the depth of the filter response are controlled by parameters such as amplitude modulation index of applied field, the coupling coefficient of the ORR, and hole-spacing and air-filling ratio of the PCF, respectively. When transmission coefficient of the loop approaches the coupling coefficient, the filter response enhances sharply with PCF parameters. The depth and the full-width at half-maximum (FWHM) of the response strongly depend on the number of field circulations in the resonator loop. With the proposed tuneability scheme for optical filter, we achieved an FWHM of ~1.55 nm. The obtained results may be utilized in designing optical add/drop filters used in WDM communication systems.

High Performance Electrocatalytic Reaction of Hydrogen and Oxygen on Ruthenium Nanoclusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Ruquan; Liu, Yuanyue; Peng, Zhiwei

2017-01-18

The development of catalytic materials for the hydrogen oxidation, hydrogen evolution, oxygen reduction or oxygen evolution reactions with high reaction rates and low overpotentials are key goals for the development of renewable energy. We report here Ru(0) nanoclusters supported on nitrogen-doped graphene as high-performance multifunctional catalysts for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), showing activities similar to that of commercial Pt/C in alkaline solution. For HER performance in alkaline media, sample Ru/NG-750 reaches 10 mA cm-2 at an overpotential of 8 mV with a Tafel slope of 30 mV dec-1. The high HER performance in alkalinemore » solution is advantageous because most catalysts for ORR and oxygen evolution reaction (OER) also prefer alkaline solution environment whereas degrade in acidic electrolytes. For ORR performance, Ru/NG effectively catalyzes the conversion of O2 into OH- via a 4e process at a current density comparable to that of Pt/C. The unusual catalytic activities of Ru(0) nanoclusters reported here are important discoveries for the advancement of renewable energy conversion reactions.« less

High surface area synthesis, electrochemical activity, and stability of tungsten carbide supported Pt during oxygen reduction in proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Chhina, H.; Campbell, S.; Kesler, O.

The oxidation of carbon catalyst supports to carbon dioxide gas leads to degradation in catalyst performance over time in proton exchange membrane fuel cells (PEMFCs). The electrochemical stability of Pt supported on tungsten carbide has been evaluated on a carbon-based gas diffusion layer (GDL) at 80 °C and compared to that of HiSpec 4000™ Pt/Vulcan XC-72R in 0.5 M H 2SO 4. Due to other electrochemical processes occurring on the GDL, detailed studies were also performed on a gold mesh substrate. The oxygen reduction reaction (ORR) activity was measured both before and after accelerated oxidation cycles between +0.6 V and +1.8 V vs. RHE. Tafel plots show that the ORR activity remained high even after accelerated oxidation tests for Pt/tungsten carbide, while the ORR activity was extremely poor after accelerated oxidation tests for HiSpec 4000™. In order to make high surface area tungsten carbide, three synthesis routes were investigated. Magnetron sputtering of tungsten on carbon was found to be the most promising route, but needs further optimization.

Porous Carbon-Hosted Atomically Dispersed Iron-Nitrogen Moiety as Enhanced Electrocatalysts for Oxygen Reduction Reaction in a Wide Range of pH

DOE PAGES

Fu, Shaofang; Zhu, Chengzhou; Su, Dong; ...

2018-02-12

As one of the alternatives to replace precious metal catalysts, transition metal-nitrogen-carbon (M-N-C) electrocatalysts have attracted great research interest due to their low cost and good catalytic activities. Despite nanostructured M-N-C catalysts can achieve good electrochemical performances, they are vulnerable to aggregation and insufficient catalytic sites upon continuous catalytic reaction. Thus, M-N-C’s stability and selectivity have not been comparable to their noble metal counterparts. In this work, metal-organic frameworks (MOFs)-derived porous single-atom electrocatalysts (SAEs) were successfully prepared by simple pyrolysis procedure without any further post-treatment. Combining the X-ray absorption near-edge spectroscopy (XANES) and electrochemical measurements, the SAEs have been identifiedmore » with superior ORR activity and stability compared with Pt/C catalysts in alkaline condition. More impressively, the SAEs also show excellent ORR electrocatalytic performance in both acid and neutral media. Furthermore, this study of nonprecious catalysts provides new insights on nano-engineering catalytically active sites and porous structures for nonprecious metal ORR catalysis in a wide range of pH.« less

Pt-Ni/WC Alloy Nanorods Arrays as ORR Catalyst for PEM Fuel Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Begum, Mahbuba; Yurukcu, Mesut; Yurtsever, Fatma

Polymer electrolyte membrane fuel cells (PEMFCs) among the other types of fuel cell technology are attractive power sources, especially for electric vehicle applications. While significant progress and plausible prospects of PEMFCs have been achieved, there are still some challenges related to the performance, durability, and cost that need to be overcome to make them economically viable for widespread commercialization. Our strategy is to develop thin films of high-active and stable catalyst coated on vertically aligned nanorod arrays of conductive and stable support. In this work, we fabricated tungsten carbide (WC) nanorods as support and coated them with a platinum-nickel (Pt-Ni)more » alloy shell denoted as Pt-Ni/WC catalysts. The Pt- Ni/WC nanorods were deposited on glassy carbon disks as well as on silicon substrates for evaluation of their electrocatalytic oxygen reduction reaction (ORR) activity and physical properties. Cyclic voltammetry experiments using rotating disk electrode were performed in perchloric acid (0.1 M HClO4) electrolyte at room temperature to characterize the ORR activity and stability of Pt-Ni/WC nanorods catalysts. Scanning electron microscopy and X-ray diffraction techniques were utilized to study the morphology and crystallographic properties, respectively.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, Joan F.

The US Department of Energy’s (DOE’s) Oak Ridge Reservation (ORR) is located in Roane and Anderson counties in East Tennessee, about 40 km (25 miles) from Knoxville. ORR is one of DOE’s most unique and complex sites. It encompasses three major facilities and thousands of employees that perform every mission in the DOE portfolio—energy research, environmental restoration, national security, nuclear fuel supply, reindustrialization, science education, basic and applied research in areas important to US security, and technology transfer. ORR was established in the early 1940s as part of the Manhattan Project for the purposes of enriching uranium and pioneering methodsmore » for producing and separating plutonium. Today, scientists at the Oak Ridge National Laboratory (ORNL), DOE’s largest multipurpose national laboratory, conduct world-leading research in advanced materials, alternative fuels, climate change, and supercomputing. The Y-12 National Security Complex (Y-12 or Y-12 Complex) is vital to maintaining the safety, security, and effectiveness of the US nuclear weapons stockpile and reducing the global threat posed by nuclear proliferation and terrorism. The East Tennessee Technology Park (ETTP), a former uranium enrichment complex, is being transitioned to a clean, revitalized industrial park.« less

Correlation between oxygen adsorption energy and electronic structure of transition metal macrocyclic complexes.

PubMed

Liu, Kexi; Lei, Yinkai; Wang, Guofeng

2013-11-28

Oxygen adsorption energy is directly relevant to the catalytic activity of electrocatalysts for oxygen reduction reaction (ORR). In this study, we established the correlation between the O2 adsorption energy and the electronic structure of transition metal macrocyclic complexes which exhibit activity for ORR. To this end, we have predicted the molecular and electronic structures of a series of transition metal macrocyclic complexes with planar N4 chelation, as well as the molecular and electronic structures for the O2 adsorption on these macrocyclic molecules, using the density functional theory calculation method. We found that the calculated adsorption energy of O2 on the transition metal macrocyclic complexes was linearly related to the average position (relative to the lowest unoccupied molecular orbital of the macrocyclic complexes) of the non-bonding d orbitals (d(z(2)), d(xy), d(xz), and d(yz)) which belong to the central transition metal atom. Importantly, our results suggest that varying the energy level of the non-bonding d orbitals through changing the central transition metal atom and/or peripheral ligand groups could be an effective way to tuning their O2 adsorption energy for enhancing the ORR activity of transition metal macrocyclic complex catalysts.

Heteroatom-doped highly porous carbon from human urine.

PubMed

Chaudhari, Nitin Kaduba; Song, Min Young; Yu, Jong-Sung

2014-06-09

Human urine, otherwise potentially polluting waste, is an universal unused resource in organic form disposed by the human body. We present for the first time "proof of concept" of a convenient, perhaps economically beneficial, and innovative template-free route to synthesize highly porous carbon containing heteroatoms such as N, S, Si, and P from human urine waste as a single precursor for carbon and multiple heteroatoms. High porosity is created through removal of inherently-present salt particles in as-prepared "Urine Carbon" (URC), and multiple heteroatoms are naturally doped into the carbon, making it unnecessary to employ troublesome expensive pore-generating templates as well as extra costly heteroatom-containing organic precursors. Additionally, isolation of rock salts is an extra bonus of present work. The technique is simple, but successful, offering naturally doped conductive hierarchical porous URC, which leads to superior electrocatalytic ORR activity comparable to state of the art Pt/C catalyst along with much improved durability and methanol tolerance, demonstrating that the URC can be a promising alternative to costly Pt-based electrocatalyst for ORR. The ORR activity can be addressed in terms of heteroatom doping, surface properties and electrical conductivity of the carbon framework.

Heteroatom-doped highly porous carbon from human urine

NASA Astrophysics Data System (ADS)

Chaudhari, Nitin Kaduba; Song, Min Young; Yu, Jong-Sung

2014-06-01

Human urine, otherwise potentially polluting waste, is an universal unused resource in organic form disposed by the human body. We present for the first time ``proof of concept'' of a convenient, perhaps economically beneficial, and innovative template-free route to synthesize highly porous carbon containing heteroatoms such as N, S, Si, and P from human urine waste as a single precursor for carbon and multiple heteroatoms. High porosity is created through removal of inherently-present salt particles in as-prepared ``Urine Carbon'' (URC), and multiple heteroatoms are naturally doped into the carbon, making it unnecessary to employ troublesome expensive pore-generating templates as well as extra costly heteroatom-containing organic precursors. Additionally, isolation of rock salts is an extra bonus of present work. The technique is simple, but successful, offering naturally doped conductive hierarchical porous URC, which leads to superior electrocatalytic ORR activity comparable to state of the art Pt/C catalyst along with much improved durability and methanol tolerance, demonstrating that the URC can be a promising alternative to costly Pt-based electrocatalyst for ORR. The ORR activity can be addressed in terms of heteroatom doping, surface properties and electrical conductivity of the carbon framework.

Impact of Polymer Electrolyte Membrane Degradation Products on Oxygen Reduction Reaction Activity for Platinum Electrocatalysts

DOE PAGES

Christ, J. M.; Neyerlin, K. C.; Wang, H.; ...

2014-10-30

The impact of model membrane degradation compounds on the relevant electrochemical parameters for the oxygen reduction reaction (i.e. electrochemical surface area and catalytic activity), was studied for both polycrystalline Pt and carbon supported Pt electrocatalysts. Model compounds, representing previously published, experimentally determined polymer electrolyte membrane degradation products, were in the form of perfluorinated organic acids that contained combinations of carboxylic and/or sulfonic acid functionality. Perfluorinated carboxylic acids of carbon chain length C1 – C6 were found to have an impact on electrochemical surface area (ECA). The longest chain length acid also hindered the observed oxygen reduction reaction (ORR) performance, resultingmore » in a 17% loss in kinetic current (determined at 0.9 V). Model compounds containing sulfonic acid functional groups alone did not show an effect on Pt ECA or ORR activity. Lastly, greater than a 44% loss in ORR activity at 0.9V was observed for diacid model compounds DA-Naf (perfluoro(2-methyl-3-oxa-5-sulfonic pentanoic) acid) and DA-3M (perfluoro(4-sulfonic butanoic) acid), which contained both sulfonic and carboxylic acid functionalities.« less

Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction.

PubMed

Yang, Liu; Cheng, Daojian; Xu, Haoxiang; Zeng, Xiaofei; Wan, Xin; Shui, Jianglan; Xiang, Zhonghua; Cao, Dapeng

2018-06-26

It is still a grand challenge to develop a highly efficient nonprecious-metal electrocatalyst to replace the Pt-based catalysts for oxygen reduction reaction (ORR). Here, we propose a surfactant-assisted method to synthesize single-atom iron catalysts (SA-Fe/NG). The half-wave potential of SA-Fe/NG is only 30 mV less than 20% Pt/C in acidic medium, while it is 30 mV superior to 20% Pt/C in alkaline medium. Moreover, SA-Fe/NG shows extremely high stability with only 12 mV and 15 mV negative shifts after 5,000 cycles in acidic and alkaline media, respectively. Impressively, the SA-Fe/NG-based acidic proton exchange membrane fuel cell (PEMFC) exhibits a high power density of 823 mW cm -2 Combining experimental results and density-functional theory (DFT) calculations, we further reveal that the origin of high-ORR activity of SA-Fe/NG is from the Fe-pyrrolic-N species, because such molecular incorporation is the key, leading to the active site increase in an order of magnitude which successfully clarifies the bottleneck puzzle of why a small amount of iron in the SA-Fe catalysts can exhibit extremely superior ORR activity.

Excitatory strength of expressive faces: effects of happy and fear expressions and context on the extinction of a conditioned fear response.

PubMed

Lanzetta, J T; Orr, S P

1986-01-01

In a recent study, Orr and Lanzetta (1984) showed that the excitatory properties of fear facial expressions previously described (Lanzetta & Orr, 1981; Orr & Lanzetta, 1980) do not depend on associative mechanisms; even in the absence of reinforcement, fear faces intensify the emotional reaction to a previously conditioned stimulus and disrupt extinction of an acquired fear response. In conjunction with the findings on acquisition, the failure to obtain extinction suggests that fear faces have some of the functional properties of "prepared" (fear-relevant) stimuli. In the present study we compared the magnitude of conditioned fear responses to happy and fear faces when a potent danger signal, the shock electrodes, are attached or unattached. If fear faces are functionally analogous to prepared stimuli, then, even in the absence of veridical support for an expectation of shock, they should retain excitatory strength, whereas happy faces should not. The results are consistent with this view of fear expressions. In the absence of reinforcement, and with shock electrodes removed, conditioned fear responses and basal levels of arousal were of greater magnitude for the fear-face condition than for the happy-face condition.

Combinatorial high-throughput optical screening of high performance Pd alloy cathode for hybrid Li-air battery.

PubMed

Jun, Young Jin; Park, Sung Hyeon; Woo, Seong Ihl

2014-12-08

Combinatorial high-throughput optical screening method was developed to find the optimum composition of highly active Pd-based catalysts at the cathode of the hybrid Li-air battery. Pd alone, which is one-third the cost of Pt, has difficulty in replacing Pt; therefore, the integration of other metals was investigated to improve its performance toward oxygen reduction reaction (ORR). Among the binary Pd-based catalysts, the composition of Pd-Ir derived catalysts had higher performance toward ORR compared to other Pd-based binary combinations. The composition at 88:12 at. % (Pd: Ir) showed the highest activity toward ORR at the cathode of the hybrid Li-air battery. The prepared Pd(88)Ir(12)/C catalyst showed a current density of -2.58 mA cm(-2) at 0.8 V (vs RHE), which was around 30% higher compared to that of Pd/C (-1.97 mA cm(-2)). When the prepared Pd(88)Ir(12)/C catalyst was applied to the hybrid Li-air battery, the polarization of the cell was reduced and the energy efficiency of the cell was about 30% higher than that of the cell with Pd/C.

Heteroatom-doped highly porous carbon from human urine

PubMed Central

Chaudhari, Nitin Kaduba; Song, Min Young; Yu, Jong-Sung

2014-01-01

Human urine, otherwise potentially polluting waste, is an universal unused resource in organic form disposed by the human body. We present for the first time “proof of concept” of a convenient, perhaps economically beneficial, and innovative template-free route to synthesize highly porous carbon containing heteroatoms such as N, S, Si, and P from human urine waste as a single precursor for carbon and multiple heteroatoms. High porosity is created through removal of inherently-present salt particles in as-prepared “Urine Carbon” (URC), and multiple heteroatoms are naturally doped into the carbon, making it unnecessary to employ troublesome expensive pore-generating templates as well as extra costly heteroatom-containing organic precursors. Additionally, isolation of rock salts is an extra bonus of present work. The technique is simple, but successful, offering naturally doped conductive hierarchical porous URC, which leads to superior electrocatalytic ORR activity comparable to state of the art Pt/C catalyst along with much improved durability and methanol tolerance, demonstrating that the URC can be a promising alternative to costly Pt-based electrocatalyst for ORR. The ORR activity can be addressed in terms of heteroatom doping, surface properties and electrical conductivity of the carbon framework. PMID:24909133

Cobalt ion-coordinated self-assembly synthesis of nitrogen-doped ordered mesoporous carbon nanosheets for efficiently catalyzing oxygen reduction.

PubMed

Wang, Haitao; Wang, Wei; Asif, Muhammad; Yu, Yang; Wang, Zhengyun; Wang, Junlei; Liu, Hongfang; Xiao, Junwu

2017-10-19

The design and synthesis of a promising porous carbon-based electrocatalyst with an ordered and uninterrupted porous structure for oxygen reduction reaction (ORR) is still a significant challenge. Herein, an efficient catalyst based on cobalt-embedded nitrogen-doped ordered mesoporous carbon nanosheets (Co/N-OMCNS) is successfully prepared through a two-step procedure (cobalt ion-coordinated self-assembly and carbonization process) using 3-aminophenol as a nitrogen source, cobalt acetate as a cobalt source and Pluronic F127 as a mesoporous template. This work indicates that the formation of a two dimensional nanosheet structure is directly related to the extent of the cobalt ion coordination interaction. Moreover, the critical roles of pyrolysis temperature in nitrogen doping and ORR catalytic activity are also investigated. Benefiting from the high surface area and graphitic degree, high contents of graphitic N and pyridinic N, ordered interconnected mesoporous carbon framework, as well as synergetic interaction between the cobalt nanoparticles and protective nitrogen doped graphitic carbon layer, the resultant optimal catalyst Co/N-OMCNS-800 (pyrolyzed at 800 °C) exhibits comparable ORR catalytic activity to Pt/C, superior tolerance to methanol crossover and stability.

Facile synthesis of sewage sludge-derived in-situ multi-doped nanoporous carbon material for electrocatalytic oxygen reduction

NASA Astrophysics Data System (ADS)

Yuan, Shi-Jie; Dai, Xiao-Hu

2016-06-01

Developing efficient, low-cost, and stable carbon-based catalysts for oxygen reduction reaction (ORR) to replace the expensive platinum-based electrocatalysts remains a major challenge that hamper the practical application of fuel cells. Here, we report that N, Fe, and S co-doped nanoporous carbon material, derived via a facile one-step pyrolysis of sewage sludge, the major byproduct of wastewater treatment, can serve as an effective electrocatalyst for ORR. Except for the comparable catalytic activity with commercial 20% Pt/C via a nearly four-electron transfer pathway in both alkaline and acid medium, the as-synthesized co-doped electrocatalyst also exhibits excellent methanol crossover resistance and outstanding long-term operation stability. The organic compounds in sewage sludge act as the carbon source and the in-situ N and S dopant in the fabrication, while the inorganic compounds serve as the in-built template and the in-situ Fe dopant. Our protocol demonstrates a new approach in the economic and eco-friendly benign reuse of sewage sludge, and also provides a straightforward route for synthesizing excellent carbon-based electrocatalysts as promising candidates for ORR directly from a type of waste/pollution.

The role of hormonal therapy in patients with relapsed high-grade ovarian carcinoma: a retrospective series of tamoxifen and letrozole.

PubMed

George, Angela; McLachlan, Jennifer; Tunariu, Nina; Della Pepa, Chiara; Migali, Cristina; Gore, Martin; Kaye, Stan; Banerjee, Susana

2017-06-30

Hormonal therapy is used as a treatment option in high-grade ovarian carcinoma (HGOC), but the role and choice of treatment remains unclear. Agents used include tamoxifen and aromatase inhibitors. Our aim was to evaluate the efficacy of tamoxifen (T) and letrozole (L) in HGOC in clinical practice and investigate factors influencing clinical outcome. A retrospective review of patients with relapsed HGOC treated with either tamoxifen or letrozole at the Royal Marsden Hospital between 2007 and 2012 was performed. The primary endpoint of the study was objective response rate (ORR). Secondary endpoints included CA125 response, clinical benefit rate (CBR) and duration of response. Platinum-sensitivity and ER-status were evaluated as predictors of treatment response. 97 patients were included (43 T, 54 L); median age 63 years (20-92); 91% high-grade serous; median number of lines of prior chemotherapy 3 (1-8); 60% platinum-resistant, 40% platinum-sensitive; 52% ER + ve, 1% ER-ve, 47% unknown. 14 patients (6 T, 8 L) achieved a partial response, with ORR (RECIST) of 14% (T) and 15% (L). The CBR for ≥3 months was 65% (22/43) for tamoxifen and 56% (22/54) for letrozole. There was no significant difference in ORR (p = 0.99) or CBR (p = 0.14) between tamoxifen and letrozole. 22 patients (23%) had a CA-125 response with hormonal therapy (10 T - 23% and 12 L - 22%). ORR did not differ by platinum sensitivity (p = 0.42); or ER-status (positive vs unknown, p = 0.12). Responders to letrozole had longer durations of response than responders to tamoxifen (26 vs 11.5 months, p = 0.03), but equivalent disease stability duration (9.6 vs 7.2 months respectively, p = 0.11). Within the constraints of a retrospective study, we identified that patients treated with letrozole had a significantly longer duration of response than those treated with tamoxifen. Treatment with either tamoxifen or letrozole is a rational treatment option for patients with ER + ve HGOC, with equivalent ORR, CBR and disease stability.

Department of Energy Operational Readiness Review for the Waste Isolation Pilot Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

The U.S. Department of Energy (DOE) has completed an Operational Readiness Review (ORR) for the restart of Contact Handled (CH) waste emplacement at the Waste Isolation Pilot Plant (WIPP) located near Carlsbad, New Mexico. The ORR team assessed the readiness of Nuclear Waste Partnership, LLC (NWP) to manage and perform receipt through CH waste emplacement, and associated waste handling and management activities, including the ability of the National TRU Program (NTP) to evaluate the waste currently stored at the WIPP site against the revised and enhanced Waste Acceptance Criteria (WAC). Field work for this review began on November 14, 2015more » and was completed on November 30, 2016. The DOE ORR was conducted in accordance with the Department of Energy Operational Readiness Review Implementation Plan for the Waste Isolation Pilot Plant, dated November 8, 2016, and DOE Order 425.1D, Verification of Readiness to Start Up or Restart Nuclear Facilities. The review activities included personnel interviews, record reviews, direct observation of operations and maintenance demonstrations, and observation of multiple operational and emergency drills/exercises. The DOE ORR also evaluated the adequacy of the contractor’s ORR (CORR) and the readiness of the DOE Carlsbad field Office (CBFO) to oversee the startup and execution of CH waste emplacement activities at the WIPP facility. The WIPP facility is categorized as a Hazard Category 2 DOE Nonreactor Nuclear Facility for all surface and Underground (UG) operations per DOE-STD-1027-92, Hazard Categorization and Accident Analysis Techniques for Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports. In addition, the WIPP experienced two events in February, 2014 that resulted in Accident Investigations being performed in accordance with the requirements of DOE Order 225.1B, Accident Investigations. Based upon the results of the accident investigations and hazard categorization of the facility, the team placed significant emphasis on the following areas: fire protection, emergency preparedness, radiological protection, nuclear safety, and operations. The identification of specific focus areas was not intended to diminish the importance of other areas of the review, but to ensure that these areas received a particularly thorough and in-depth evaluation due to their significance with respect to the safe operation of the facility.« less

Physical Conditioning through Water Exercises.

ERIC Educational Resources Information Center

Conrad, C. Carson

This document describes activities in an aquatic program designed for an individual in sound health. Instructions for performing each activity are given in step-by-step outline form. The activities are arranged under the following categories: standing water drills; pool-side standing drills; gutter holding drills; bobbing (various forms);…

Methow River Studies, Washington: abundance estimates from Beaver Creek and the Chewuch River screw trap, methodology testing in the Whitefish Island side channel, and survival and detection estimates from hatchery fish releases, 2013

USGS Publications Warehouse

Martens, Kyle D.; Fish, Teresa M.; Watson, Grace A.; Connolly, Patrick J.

2014-01-01

Salmon and steelhead populations have been severely depleted in the Columbia River from factors such as the presence of tributary dams, unscreened irrigation diversions, and habitat degradation from logging, mining, grazing, and others (Raymond, 1988). The U.S. Geological Survey (USGS) has been funded by the Bureau of Reclamation (Reclamation) to provide evaluation of on-going Reclamation funded efforts to recover Endangered Species Act (ESA) listed anadromous salmonid populations in the Methow River watershed, a watershed of the Columbia River in the Upper Columbia River Basin, in north-central Washington State (fig. 1). This monitoring and evaluation program was funded to document Reclamation’s effort to partially fulfill the 2008 Federal Columbia River Power System Biological Opinion (BiOp) (National Oceanographic and Atmospheric Administration, Fisheries Division 2003). This Biological Opinion includes Reasonable and Prudent Alternatives (RPA) to protect listed salmon and steelhead across their life cycle. Species of concern in the Methow River include Upper Columbia River (UCR) spring Chinook salmon (Oncorhynchus tshawytscha), UCR summer steelhead (O. mykiss), and bull trout (Salvelinus confluentus), which are all listed as threatened or endangered under the ESA. The work done by the USGS since 2004 has encompassed three phases of work. The first phase started in 2004 and continued through 2012. This first phase involved the evaluation of stream colonization and fish production in Beaver Creek following the modification of several water diversions (2000–2006) that were acting as barriers to upstream fish movement. Products to date from this work include: Ruttenburg (2007), Connolly and others (2008), Martens and Connolly (2008), Connolly (2010), Connolly and others (2010), Martens and Connolly (2010), Benjamin and others (2012), Romine and others (2013a), Weigel and others (2013a, 2013b, 2013c), and Martens and others (2014). The second phase, initiated in 2008, focuses on the evaluation of the M2 reach (rkm 66– 80) of the mainstem Methow River prior to restoration actions planned by Reclamation and Yakama Nation. The M2 study was designed to help understand the inter-relationships between stream habitat and the life history of various fish species to explain potential success or limitations in response to restoration actions. To help document changes derived by restoration, two reference reaches (Upper Methow between rkm 85 and 90, and Chewuch River between rkm 4 and 11) were identified based on relative lack of disturbance, proximity to the restoration reach, and relative unconfined geomorphology. A control reach (Lower Methow between rkm 57 and 64, also referred to as “Silver Reach”) was 2 identified based on its similar disturbance as the reference reach, proximity to the restoration reach, and relatively unconfined geomorphology. Products to date include Barber and others (2011), Bellmore (2011), Tibbits and others (2012), Bellmore and others (2013), Benjamin and others (2013), Romine and others (2013b), Bellmore and other (2014), Martens and others (2014), and Martens and Connolly (2014). The third phase of work has been to help with the development and to provide data for modeling efforts. Most of the planned M2 reach restoration is focused on the creation or improvement of offchannel habitat, especially side channels. The pre-restoration portion of this study has been documented by Martens and Connolly (2014). Side channel restoration actions were initiated in 2012 (Whitefish Island side channel, also referred to as SC3; rkm 76) and are planned to continue over the next several years. The Whitefish Island side channel was modified to maintain hydrological connection with the mainstem throughout the year. In addition, several log structures were installed and pools were deepened to create fish habitat. Prior to restoration, this side channel would lose hydrological connection with the mainstem Methow River, leaving one large pool near the bottom of the side channel and several shallow isolated pools that may or may not go dry. In seasonally connected side channels, juvenile salmonid survival in pools less than 100 cm average depth was lower than in pools greater than 100 cm average depth (Martens and Connolly, 2014). In this report, we document our field work and analysis completed in 2013. During 2013, USGS sampling efforts were focused on resampling of three reaches in Beaver Creek, testing methodology in the Whitefish Island side channel, conducting hatchery survival estimates, and operating a screw trap on the Chewuch River (funded by Yakama Nation; fig. 1). The Beaver Creek sampling effort was a revisit of three index sites sampled continuously from 2004 to 2007 to look at the fish response to barrier removal. Methodology testing in Whitefish Island side channel was done to determine the best method for evaluating fish populations after restoration efforts in side channels (previous sampling methods were determined to be ineffective after pools were deepened). Hatchery survival estimates were completed to monitor fish survival in the Methow and Columbia Rivers, while the screw trap was operated to estimate migrating fish populations in the Chewuch River and track passive integrated transponder (PIT)-tagged fish. In addition, we maintained a network of PIT-tag interrogation systems (PTIS), assisted Reclamation with fish removal events associated with stream restoration (two people for 9 days; 14 percent of summer field season), and conducted a stream metabolism study designed to help parameterize and calibrate the stream productivity model (Bellmore and others, 2014) with model validation.

STS-35 Commander Brand listens to trainer during water egress exercises

NASA Technical Reports Server (NTRS)

1990-01-01

STS-35 Commander Vance D. Brand listens to training personnel during launch emergency egress procedures conducted in JSC's Weightless Environment Training Facility (WETF) Bldg 29. Brand, wearing a launch and entry suit (LES) and launch and entry helmet (LEH), is seated on the pool side while reviewing instructions.

Spinel CuCo2O4 nanoparticles supported on N-doped reduced graphene oxide: a highly active and stable hybrid electrocatalyst for the oxygen reduction reaction.

PubMed

Ning, Rui; Tian, Jingqi; Asiri, Abdullah M; Qusti, Abdullah H; Al-Youbi, Abdulrahman O; Sun, Xuping

2013-10-29

In this Letter, for the first time, we demonstrated the preparation of a highly efficient electrocatalyst, spinel CuCo2O4 nanoparticles supported on N-doped reduced graphene oxide (CuCo2O4/N-rGO), for an oxygen reduction reaction (ORR) under alkaline media. The hybrid exhibits higher ORR catalytic activity than CuCo2O4 or N-rGO alone, the physical mixture of CuCo2O4 nanoparticles and N-rGO, and Co3O4/N-rGO. Moreover, such a hybrid affords superior durability to the commercial Pt/C catalyst.

Carbon-based electrocatalysts for advanced energy conversion and storage

PubMed Central

Zhang, Jintao; Xia, Zhenhai; Dai, Liming

2015-01-01

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries. Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries. We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance. PMID:26601241

Non-platinum metal-organic framework based electro-catalyst for promoting oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Das, Dipanwita; Raut, Vrushali; Kireeti, Kota V. M. K.; Jha, Neetu

2018-04-01

We developed two non-precious Metal Organic Framework (MOF) based electrocatalysts, MOF-5 and MOF-i using solvothermal and refluxing methods. The MOFs prepared has been characterized by powder X-ray diffractometer (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) for structural and morphological insights. SEM images reveal cubic shape for solvothermally synthesized MOF-5, whereas refluxing method leads to platelet morphology of MOF-i. The synthesized MOFs has been investigated for Oxygen Reduction Reaction (ORR) studies using Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV), with MOF modified Glassy Carbon (GC) as working electrode. The electrochemical data suggests higher activity of MOF-5 towards ORR compared to MOF-i.

Effectiveness of medical treatment for Cushing's syndrome: a systematic review and meta-analysis.

PubMed

Broersen, Leonie H A; Jha, Meghna; Biermasz, Nienke R; Pereira, Alberto M; Dekkers, Olaf M

2018-05-31

To systematically review the effectiveness of medical treatment for Cushing's syndrome in clinical practice, regarding cortisol secretion, clinical symptom improvement, and quality of life. To assess the occurrence of side effects of these medical therapies. Eight electronic databases were searched in March 2017 to identify potentially relevant articles. Randomized controlled trials and cohort studies assessing the effectiveness of medical treatment in patients with Cushing's syndrome, were eligible. Pooled proportions were reported including 95% confidence intervals. We included 35 articles with in total 1520 patients in this meta-analysis. Most included patients had Cushing's disease. Pooled reported percentage of patients with normalization of cortisol ranged from 35.7% for cabergoline to 81.8% for mitotane in Cushing's disease. Patients using medication monotherapy showed a lower percentage of cortisol normalization compared to use of multiple medical agents (49.4 vs. 65.7%); this was even higher for patients with concurrent or previous radiotherapy (83.6%). Mild side effects were reported in 39.9%, and severe side effects were seen in 15.2% of patients after medical treatment. No meta-analyses were performed for clinical symptom improvement or quality of life due to lack of sufficient data. This meta-analysis shows that medication induces cortisol normalization effectively in a large percentage of patients. Medical treatment for Cushing's disease patients is thus a reasonable option in case of a contraindication for surgery, a recurrence, or in patients choosing not to have surgery. When experiencing side effects or no treatment effect, an alternate medical therapy or combination therapy can be considered.

Manganese oxide/poly(3,4-ethylenedioxythiophene) hybrid electrocatalysts for the oxygen reduction reaction in alkaline fuel cells

DOE PAGES

Lambert, Timothy N.; Vigil, Julian A.

2016-08-22

Manganese oxide/poly(3,4-ethylene-dioxythiophene) (MnO x/ PEDOT) nanostructured hybrid thin films were prepared using a simple anodic electrodeposition process from aqueous solution, and then tested for oxygen reduction reaction (ORR) activity in alkaline electrolyte using rotating disk electrode and rotating ring disk electrode methods. MnO x/PEDOT provided improvements over MnO x-only and PEDOT-only control films, with > 0.2 V decrease in onset and half-wave overpotentials, and > 1.5 times increase in terminal current density. The MnO x/PEDOT film exhibited only a slightly lower n value (n = 3.86-3.92) than the 20% Pt/C benchmark electrocatalyst (n = 3.98) across all potentials. MnO x/PEDOTmore » also displayed a more positive half-wave potential and superior electrocatalytic selectivity for the ORR upon methanol exposure than 20% Pt/C. Here, the high activity and synergism of MnO x/PEDOT towards the ORR is attributed to effective intermixing/dispersion of the two materials, intimate substrate contact with improved charge transfer processes attained by co-electrodepositing MnO x with PEDOT and due to the increase in Mn 3+ content at the surface of the oxide.« less

Hierarchical hybrid of Ni3N/N-doped reduced graphene oxide nanocomposite as a noble metal free catalyst for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Zhao, Qi; Li, Yingjun; Li, Yetong; Huang, Keke; Wang, Qin; Zhang, Jun

2017-04-01

Novel nickel nitride (Ni3N) nanoparticles supported on nitrogen-doped reduced graphene oxide nanosheets (N-RGOs) are synthesized via a facile strategy including hydrothermal and subsequent calcination methods, in which the reduced graphene oxide nanosheets (RGOs) are simultaneously doped with nitrogen species. By varying the content of the RGOs, a series of Ni3N/N-RGO nanocomposites are obtained. The Ni3N/N-RGO-30% hybrid nanocomposite exhibits superior catalytic activity towards oxygen reduction reaction (ORR) under alkaline condition (0.1 M KOH). Furthermore, this hybrid catalyst also demonstrates high tolerance to methanol poisoning. The RGO containing rich N confers the nanocomposite with large specific surface area and high electronic conduction ability, which can enhance the catalytic efficiency of Ni3N nanoparticles. The enhanced catalytic activity can be attributed to the synergistic effect between Ni3N and nitrogen doped reduced graphene oxide. In addition, the sufficient contact between Ni3N nanoparticles and the N-RGO nanosheets simultaneously promotes good nanoparticle dispersion and provides a consecutive activity sites to accelerate electron transport continuously, which further enhance the ORR performance. The Ni3N/N-RGO may be further an ideal candidate as efficient and inexpensive noble metal-free ORR electrocatalyst in fuel cells.

A hybrid DNA-templated gold nanocluster for enhanced enzymatic reduction of oxygen

DOE PAGES

Chakraborty, Saumen; Babanova, Sofia; Rocha, Reginaldo C.; ...

2015-08-19

We report the synthesis and characterization of a new DNA-templated gold nanocluster (AuNC) of ~1 nm in diameter and possessing ~7 Au atoms. When integrated with bilirubin oxidase (BOD) and single walled carbon nanotubes (SWNTs), the AuNC acts as an enhancer of electron transfer (ET) and lowers the overpotential of electrocatalytic oxygen reduction reaction (ORR) by ~15 mV as compared to the enzyme alone. In addition, the presence of AuNC causes significant enhancements in the electrocatalytic current densities at the electrode. Control experiments show that such enhancement of ORR by the AuNC is specific to nanoclusters and not to plasmonicmore » gold particles. Rotating ring disk electrode (RRDE) measurements confirm 4e– reduction of O 2 to H 2O with minimal production of H 2O 2, suggesting that the presence of AuNC does not perturb the mechanism of ORR catalyzed by the enzyme. This unique role of the AuNC as enhancer of ET at the enzyme-electrode interface makes it a potential candidate for the development of cathodes in enzymatic fuel cells, which often suffer from poor electronic communication between the electrode surface and the enzyme active site. In conclusion, the AuNC displays phosphorescence with large Stokes shift and microsecond lifetime.« less

Mechanism of H adatoms improving the O2 reduction reaction on the Zn-modified anatase TiO2 (101) surface studied by first principles calculation.

PubMed

Liu, Liangliang; Li, Chongyang; Jiang, Man; Li, Xiaodong; Huang, Xiaowei; Wang, Zhu; Jia, Yu

2018-06-05

First principles calculations were performed to cast insight into the mechanism of the improvement of O2 reduction reaction (ORR) activity by Zn and H interstitials on the anatase TiO2 (101) surface. For the Zn-modified anatase TiO2 (101) surface, both surface and subsurface Zn interstitials could contribute to O2 adsorption and dissociation, but the dissociation barriers of O2 molecules are still too high, which limits the ORR activity. After a H adatom is introduced onto the Zn-modified anatase TiO2 (101) surface, the highest energy barriers are greatly reduced compared with those of the Zn-modified surface. Meanwhile, it is observed that the dissociation barriers decrease almost linearly with the increase of the charge difference of adsorption O2 between initial and transition state configurations. Specifically, subsurface Zn and surface H interstitials facilitate O2 dissociation and subsequent oxidation reactions, and further frequency analysis shows that these dissociation processes are frequent even at the room temperature of 300 K. In a word, this work provides a theoretical support to design a high ORR activity catalyst of the TiO2 nanocrystal comparable to precious Pt catalysts.

Simultaneous reduction and nitrogen functionalization of graphene oxide using lemon for metal-free oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Begum, Halima; Ahmed, Mohammad Shamsuddin; Cho, Sung; Jeon, Seungwon

2017-12-01

Inspire by the vision of finding a simple and green method for simultaneous reduction and nitrogen (N)-functionalization of graphene oxide (GO), a N-rich reduced graphene oxide (rGO) has been synthesized through a facile and ecofriendly hydrothermal strategy while most of the existing methods are involving with multiple steps and highly toxic reducing agents that are harmful to human health and environment. In this paper, the simultaneous reduction and N-functionalization of GO using as available lemon juice (denoted as Lem-rGO) for metal-free electrocatalysis towards oxygen reduction reaction (ORR) is described. The proposed method is based on the reduction of GO using of the reducing and the N-precursor capability of ascorbic acid and citric acid as well as the nitrogenous compounds, respectively, that containing in lemon juice. The resultant Lem-rGO has higher reduction degree, higher specific surface area and better crystalline nature with N-incorporation than that of well investigated ascorbic acid and citric acid treated rGO. As a result, it shows better ORR electrocatalytic activity in respect to the improved onset potential, electron transfer rate and kinetics than those typical rGO catalysts. Moreover, it shows a significant tolerance to the anodic fuels and durability than the Pt/C during ORR.

A pilot study of durvalumab and tremelimumab and immunogenomic dynamics in metastatic breast cancer

PubMed Central

Santa-Maria, Cesar August; Kato, Taigo; Park, Jae-Hyun; Kiyotani, Kazuma; Rademaker, Alfred; Shah, Ami N.; Gross, Leeaht; Blanco, Luis Z.; Jain, Sarika; Flaum, Lisa; Tellez, Claudia; Stein, Regina; Uthe, Regina; Gradishar, William J.; Cristofanilli, Massimo; Nakamura, Yusuke; Giles, Francis J.

2018-01-01

Immune checkpoint inhibitors produce modest responses in metastatic breast cancer, however, combination approaches may improve responses. A single arm pilot study was designed to determine the overall response rate (ORR) of durvalumab and tremelimumab, and evaluate immunogenomic dynamics in metastatic endocrine receptor (ER) positive or triple negative breast cancer (TNBC). Simon two-stage design indicated at least four responses from the first 18 patients were needed to proceed with the second stage. T-cell receptor (TCR) sequencing and immune-gene expression profiling were conducted at baseline and two months, whole exome sequencing was conducted at baseline. Eighteen evaluable patients were accrued (11 ER-positive; seven TNBC). Only three patients had a response (ORR = 17%), thus the study did not proceed to the second stage. Responses were only observed in patients with TNBC (ORR = 43%). Responders versus non-responders had upregulation of CD8, granzyme A, and perforin 1 gene expression, and higher mutational and neoantigen burden. Patients with TNBC had an oligoclonal shift of the most abundant TCR-beta clonotypes compared to those with ER-positive disease, p = 0.004. We conclude responses are low in unselected metastatic breast cancer, however, higher rates of clinical benefit were observed in TNBC. Immunogenomic dynamics may help identify phenotypes most likely to respond to immunotherapy. PMID:29721177

A novel iron (Ⅱ) polyphthalocyanine catalyst assembled on graphene with significantly enhanced performance for oxygen reduction reaction in alkaline medium

NASA Astrophysics Data System (ADS)

Lin, Lin; Li, Meng; Jiang, Liqing; Li, Yongfeng; Liu, Dajun; He, Xingquan; Cui, Lili

2014-12-01

To realize the large-scale commercial application of direct methanol fuel cells (DMFCs), the catalysts for oxygen reduction reaction (ORR) are the crucial obstacle. Here, an efficient non-noble-metal catalyst for ORR, denoted FePPc/PSS-Gr, has been obtained by anchoring p-phenyl-bis(3,4-dicyanophenyl) ether iron(Ⅱ) polyphthalocyanine (FePPc) on poly(sodium-p-styrenesulfonate) (PSS) modified graphene (PSS-Gr) through a solvothermally assisted π-π assembling approach. The Ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results reveal the π-π interaction between FePPc and PSS-Gr. The rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) measurements show that the proposed catalyst possesses an excellent catalytic performance towards ORR comparable with the commercial Pt/C catalyst in alkaline medium, such as high onset potential (-0.08 V vs. SCE), half-wave potential (-0.19 V vs. SCE), better tolerance to methanol crossover, excellent stability (81.1%, retention after 10,000 s) and an efficient four-electron pathway. The enhanced electrocatalytic performance could be chiefly attributed to its large electrochemically accessible surface area, fast electron transfer rate of PSS-Gr, in particular, the synergistic effect between the FePPc moieties and the PSS-Gr sheets.

2,3-diaminopyridine functionalized reduced graphene oxide-supported palladium nanoparticles with high activity for electrocatalytic oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Yasmin, Sabina; Joo, Yuri; Jeon, Seungwon

2017-06-01

The electrochemical deposition of Pd nanoparticles (Pd NPs) on 2,3 diamino pyridine functionalized reduced graphene oxide (2,3 DAP-rGO/Pd) has been investigated for the oxygen reduction reaction (ORR) in alkaline media. First, 2,3 diaminopyridine functionalized graphene oxide (2,3 DAP-rGO) has been synthesized via simple hydrothermal method. Then, palladium is directly incorporated into the 2,3 DAP-rGO by electrochemical deposition method to generate 2,3 DAP-rGO/Pd composites. The as-prepared material 2,3 DAP-rGO/Pd has been characterized by various instrumental methods. The morphological analysis shows the cluster-like Pd nanoparticles are dispersed onto the 2,3 diamino pyridine functionalized reduced graphene oxide (2,3 DAP-rGO). The electrocatalytic activities have been verified using cyclic voltammetry (CV) and hydrodynamic voltammetry and chronoamperometry techniques in 0.1 M KOH electrolyte. The as-synthesized 2,3 DAP-rGO/Pd shows higher catalytic activity toward ORR with more positive onset potential and cathodic current density, superior methanol/ethanol tolerance and excellent stability in alkaline medium. It is also noteworthy that the 2,3 DAP-rGO/Pd exhibits a four-electron transfer pathway for ORR with lower H2O2 yield.

Oxidation of platinum nickel nanowires to improve durability of oxygen-reducing electrocatalysts

DOE PAGES

Alia, Shaun M.; Pylypenko, Svitlana; Dameron, Arrelaine; ...

2016-01-12

In this study, the impact of heat treating platinum-coated nickel (Pt-Ni) nanowires in oxygen is examined to determine the effect on oxygen reduction (ORR) activity and durability. Pt-Ni nanowires exhibit promising ORR mass activities (3 times greater than Pt nanoparticles, 1.5 times greater than U.S. Department of Energy target) both before and after potential cycling for all but the highest annealing temperatures explored. The annealing of Pt-Ni nanowires in oxygen with increasing temperature is found to reduce surface area and ORR activity in comparison to the untreated material, but also reduces activity losses following durability testing. Following potential cycling, unannealedmore » Pt-Ni nanowires show significant losses in surface area (23%) and specific activity (18%) while Pt-Ni nanowires annealed at 200°C show modest increases in surface area (2%) and specific activity (6%) after potential cycling. Increasing annealing temperatures also show a clear trend of decreasing Ni dissolution rates. While oxygen annealing has shown the ability to improve durability of Pt-Ni nanowires, significant Ni dissolution was observed in all samples and suggests oxide passivation while showing promise for improved durability, when employed by itself is insufficient to prevent all contamination concerns involving Ni dissolution.« less

3D interconnected hierarchical porous N-doped carbon constructed by flake-like nanostructure with Fe/Fe3C for efficient oxygen reduction reaction and supercapacitor.

PubMed

Li, Guoning; Zhang, Jiajun; Li, Weisong; Fan, Kai; Xu, Chunjian

2018-05-17

Hierarchical porous N-doped carbon with Fe/Fe3C nanoparticles, high content of N dopants (10.51 wt%), and a 3D interconnected porous architecture constructed by flake-like nanostructure was facilely prepared by carbonization of a zeolitic imidazolate framework-8 (ZIF-8) as a self-sacrificing template and potassium ferricyanide (PF) as a multifunctional iron precursor. The unique porous structure can offer a continuous pathway for electron transfer and shorten the mass transfer pathway, which contribute to both an oxygen reduction reaction (ORR) and a supercapacitor. The influence of the carbonization temperature and iron content on the performance of ORR and supercapacitor was investigated. The as-prepared composites carbonized at 800 °C (Fe-CZIF-800-10) displayed comparable ORR activity with Pt/C in alkaline media as well as excellent long-term stability, superb methanol tolerance, and appreciable onset potential in acid media. Moreover, Fe-CZIF-800-10 exhibited excellent capacity of 246 F g-1 at a current density of 0.5 A g-1 and stability in 6 M KOH. This report provides a facile approach to prepare hierarchical porous Fe/N-doped carbon as a promising electrode material for both fuel cell and supercapacitor applications.

Morphology inherence from hollow MOFs to hollow carbon polyhedrons in preparing carbon-based electrocatalysts

DOE PAGES

Pei, Yuchen; Qi, Zhiyuan; Li, Xinle; ...

2017-02-21

Hollow carbon nanostructures are emerging as advanced electrocatalysts for the oxygen reduction reaction (ORR) due to the effective usage of active sites and the reduced dependence on expensive noble metals. Conventional preparation of these hollow structures is achieved through templates (e.g. SiO 2, CdS, and Ni 3C), which serve to retain the void interiors during carbonization, leading to an essential template-removal procedure using hazardous chemical etchants. Herein, we demonstrate the direct carbonization of unique hollow zeolitic imidazolate frameworks (ZIFs) for the synthesis of hollow carbon polyhedrons (HCPs) with well-defined morphologies. The hollow ZIF particles behave bi-functionally as a carbon sourcemore » and a morphology directing agent. This method evidences the strong morphology inherence from the hollow ZIFs during the carbonization, advancing the significant simplicity and environmental friendliness of this synthesis strategy. The as-prepared HCPs show a uniform polyhedral morphology and large void interiors, which enable their superior ORR activity. Iron can be doped into the HCPs (Fe/HCPs), providing the Fe/HCPs with enhanced ORR properties ( E 1/2 = 0.850 V) in comparison with those of HCPs. As a result, we highlight the efficient structural engineering to transform ZIFs into advanced carbon nanostructures accomplishing morphological control and high electrocatalytic activity.« less

Manganese oxide/poly(3,4-ethylenedioxythiophene) hybrid electrocatalysts for the oxygen reduction reaction in alkaline fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, Timothy N.; Vigil, Julian A.

Manganese oxide/poly(3,4-ethylene-dioxythiophene) (MnO x/ PEDOT) nanostructured hybrid thin films were prepared using a simple anodic electrodeposition process from aqueous solution, and then tested for oxygen reduction reaction (ORR) activity in alkaline electrolyte using rotating disk electrode and rotating ring disk electrode methods. MnO x/PEDOT provided improvements over MnO x-only and PEDOT-only control films, with > 0.2 V decrease in onset and half-wave overpotentials, and > 1.5 times increase in terminal current density. The MnO x/PEDOT film exhibited only a slightly lower n value (n = 3.86-3.92) than the 20% Pt/C benchmark electrocatalyst (n = 3.98) across all potentials. MnO x/PEDOTmore » also displayed a more positive half-wave potential and superior electrocatalytic selectivity for the ORR upon methanol exposure than 20% Pt/C. Here, the high activity and synergism of MnO x/PEDOT towards the ORR is attributed to effective intermixing/dispersion of the two materials, intimate substrate contact with improved charge transfer processes attained by co-electrodepositing MnO x with PEDOT and due to the increase in Mn 3+ content at the surface of the oxide.« less

Remedial investigation work plan for the Upper East Fork Poplar Creek Characterization Area, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-03-01

More than 200 contaminated sites created by past waste management practices have been identified at the Y-12 Plant. Many of the sites have been grouped into operable units based on priority and on investigative and remediation requirements. The Y-12 Plant is one of three major facilities on the ORR. The ORR contains both hazardous and mixed-waste sites that are subject to regulations promulgated under the Resource Conservation and Recovery Act of 1976 (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and Reauthorization Act of 1986. Under RCRA guidelines andmore » requirements from the Tennessee Department of Environment and Conservation (TDEC), the Y-12 Plant initiated investigation and monitoring of various sites within its boundaries in the mid-1980s. The entire ORR was placed on the National Priorities List (NPL) of CERCLA sites in November 1989. Following CERCLA guidelines, sites under investigation require a remedial investigation (RI) to define the nature and extent of contamination, evaluate the risks to public health and the environment, and determine the goals for a feasibility study (FS) of potential remedial actions.« less

[Clinical observation of DECP combination chemotherapy for relapsing and refractory multiple myeloma patients with extramedullary plasmacytomas].

PubMed

Li, Xin; Sun, Wanjun; Jin, Fengyan; Chen, Shilun; Zhong, Yuping; Hu, Ying; Zhang, Jiajia; An, Na; Shen, Man; Huang, Zhongxia

2014-04-29

To explore the clinical effect and toxicity of (cisplatin, etoposide, ifosfamide & dexamethasone) DECP combination chemotherapy in the treatment of relapsing and refractory multiple myeloma (MM) with extramedullary plasmacytomas. A total of 20 relapsed and refractory MM patients with extramedullary plasmacytomas treated with DECP regimen from May 2005 to May 2013 were analyzed retrospectively. DECP protocols included cisplatin 20 mg/m(2), Day 1-3; etoposide 100 mg/d,Day 1-3; ifosfamide 500 mg·m(-2)·d(-1), Day 1-4; dexamethasone 20 mg/d, Day 1-4. Efficacy was evaluated after 2 therapeutic cycles. After 2 therapeutic cycles, the objective response rate (ORR) was 55% (11/20). After 3 therapeutic cycles, the ORR was 7/12.Seven patients completed 4 cycles with an ORR of 4/7. Two patients had finished 6 cycles and continued to maintain partial remission. The most common adverse events included gastrointestinal reaction and myelosuppression. The median follow-up time was 30 (12-80) months. The median time of overall survival (OS) was 30 (9-121) months. The 1-year OS was 73%, 2-year OS 28% and 3-year OS 21%. The DECP chemotherapy is both effective and safe in the treatment of relapsed and refractory MM patients with extramedullary plasmacytomas.

B and N isolate-doped graphitic carbon nanosheets from nitrogen-containing ion-exchanged resins for enhanced oxygen reduction

NASA Astrophysics Data System (ADS)

Wang, Lei; Yu, Peng; Zhao, Lu; Tian, Chungui; Zhao, Dongdong; Zhou, Wei; Yin, Jie; Wang, Ruihong; Fu, Honggang

2014-06-01

B,N-codoped carbon nanostructures (BNCS) can serve as alternative low-cost metal-free electrocatalysts for oxygen reduction reactions (ORR). However, the compensation effect between the p- (B atoms) and n-type (N atoms) dopants would make the covalent boron-nitride (BN) easily formed during the synthesis of BNCS, leading to a unsatisfactory ORR activity. Therefore, it has been challenging to develop facile and rapid synthetic strategies for highly active BNCS without forming the direct covalent BN. Here, a facile method is developed to prepare B and N isolate-doped graphitic nanosheets (BNGS) by using iron species for saving N element and simultaneous doping the B element from nitrogen-containing ion-exchanged resins (NR). The resulting BNGS exhibits much more onset potential (Eonset) compared with the B-doped graphitic carbon nanosheets (BGS), N-doped graphitic carbon nanosheets (NGS), as well as B,N-codoped disorder carbon (BNC). Moreover, the BNGS shows well methanol tolerance propery and excellent stability (a minimal loss of activity after 5,000 potential cycles) compared to that of commercial Pt/C catalyst. The goog performance for BNGS towards ORR is attributed to the synergistic effect between B and N, and the well electrons transport property of graphitic carbon in BNGS.

DFT Study of the Oxygen Reduction Reaction Activity on Fe−N4-Patched Carbon Nanotubes: The Influence of the Diameter and Length

PubMed Central

Chen, Xin; Hu, Rui; Bai, Fan

2017-01-01

The influences of diameter and length of the Fe−N4-patched carbon nanotubes (Fe−N4/CNTs) on oxygen reduction reaction (ORR) activity were investigated by density functional theory method using the BLYP/DZP basis set. The results indicate that the stability of the Fe−N4 catalytic site in Fe−N4/CNTs will be enhanced with a larger tube diameter, but reduced with shorter tube length. A tube with too small a diameter makes a Fe−N4 site unstable in acid medium since Fe−N and C−N bonds must be significantly bent at smaller diameters due to hoop strain. The adsorption energy of the ORR intermediates, especially of the OH group, becomes weaker with the increase of the tube diameter. The OH adsorption energy of Fe−N4/CNT with the largest tube diameter is close to that on Pt(111) surface, indicating that its catalytic property is similar to Pt. Electronic structure analysis shows that the OH adsorption energy is mainly controlled by the energy levels of Fe 3d orbital. The calculation results uncover that Fe−N4/CNTs with larger tube diameters and shorter lengths will exhibit better ORR activity and stability. PMID:28772903

Influence of various carbon nano-forms as supports for Pt catalyst on proton exchange membrane fuel cell performance

NASA Astrophysics Data System (ADS)

Bharti, Abha; Cheruvally, Gouri

2017-08-01

In this study, we discuss the influence of various carbon supports for Pt on proton exchange membrane (PEM) fuel cell performance. Here, Pt supported on various carbon nano-forms [Pt/carbon black (Pt/CB), Pt/single-walled carbon nanotubes (Pt/SWCNT), Pt/multi-walled carbon nanotubes (Pt/MWCNT) and Pt/graphene (Pt/G)] are synthesized by a facile, single step, microwave-assisted, modified chemical reduction route. Their physical, chemical and electrochemical characteristics pertaining to oxygen reduction reaction (ORR) catalytic activity and stability in PEM fuel cell are studied in detail by various techniques and compared. The study shows that the different carbon supports does not significantly affect the Pt particle size during synthesis, but leads to different amount of defective sites in the carbon framework which influence both the availability of active metal nano-catalysts and metal-support interaction. In-situ electrochemical investigations reveal that the different carbon supports influence both ORR catalytic activity and stability of the catalyst. This is further corroborated by the demonstration of varying polarization characteristics on PEM fuel cell performance by different carbon supported Pt catalysts. This study reveals MWCNT as the most suitable carbon support for Pt catalyst, exhibiting high activity and stability for ORR in PEM fuel cell.

Objective responses in relapsed T-cell lymphomas with single-agent brentuximab vedotin

PubMed Central

Advani, Ranjana H.; Bartlett, Nancy L.; Jacobsen, Eric D.; Sharman, Jeff P.; O’Connor, Owen A.; Siddiqi, Tanya; Kennedy, Dana A.; Oki, Yasuhiro

2014-01-01

This phase 2, open-label, multicenter study evaluated the efficacy and safety of brentuximab vedotin, a CD30-directed antibody-drug conjugate, in relapsed/refractory CD30+ non-Hodgkin lymphomas. The primary end point was objective response rate (ORR). Key secondary end points included safety, correlation of CD30 expression with response, response duration, and progression-free survival (PFS). Brentuximab vedotin 1.8 mg/kg was administered every 3 weeks until progression or unacceptable toxicity. This planned subset analysis included patients with peripheral T-cell lymphomas (PTCLs; n = 35), specifically angioimmunoblastic T-cell lymphoma (AITL; n = 13) and PTCL not otherwise specified (n = 22). Median age was 64 years; 63% were refractory to most recent therapy. Of 34 evaluable patients, ORR was 41% (8 complete remissions [CRs], 6 partial remissions [PRs]), and ORR was 54% in AITL (5 CRs, 2 PRs) with median PFS of 6.7 months thus far. No correlation between CD30 expression per central review and response was observed. Safety data were consistent with the known profile of brentuximab vedotin, and included at least grade 3 events of neutropenia (14%), peripheral sensory neuropathy, and hyperkalemia (9% each). In summary, brentuximab vedotin showed antitumor activity in patients with relapsed PTCL particularly AITL. This trial was registered at www.clinicaltrials.gov as #NCT01421667. PMID:24652992

Morphology inherence from hollow MOFs to hollow carbon polyhedrons in preparing carbon-based electrocatalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pei, Yuchen; Qi, Zhiyuan; Li, Xinle

Hollow carbon nanostructures are emerging as advanced electrocatalysts for the oxygen reduction reaction (ORR) due to the effective usage of active sites and the reduced dependence on expensive noble metals. Conventional preparation of these hollow structures is achieved through templates (e.g. SiO 2, CdS, and Ni 3C), which serve to retain the void interiors during carbonization, leading to an essential template-removal procedure using hazardous chemical etchants. Herein, we demonstrate the direct carbonization of unique hollow zeolitic imidazolate frameworks (ZIFs) for the synthesis of hollow carbon polyhedrons (HCPs) with well-defined morphologies. The hollow ZIF particles behave bi-functionally as a carbon sourcemore » and a morphology directing agent. This method evidences the strong morphology inherence from the hollow ZIFs during the carbonization, advancing the significant simplicity and environmental friendliness of this synthesis strategy. The as-prepared HCPs show a uniform polyhedral morphology and large void interiors, which enable their superior ORR activity. Iron can be doped into the HCPs (Fe/HCPs), providing the Fe/HCPs with enhanced ORR properties ( E 1/2 = 0.850 V) in comparison with those of HCPs. As a result, we highlight the efficient structural engineering to transform ZIFs into advanced carbon nanostructures accomplishing morphological control and high electrocatalytic activity.« less

Synthesis and Catalytic Activity of Pt Monolayer on Pd Tetrahedral Nanocrystals with CO-adsorption-induced Removal of Surfactants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong K.; Vukmirovic M.B.; Ma C.

2011-11-01

We synthesized the Pt monolayer shell-Pd tetrahedral core electrocatalysts that are notable for their high activity and stable performance. A small number of low-coordination sites and defects, and high content of the (1 1 1)-oriented facets on Pd tetrahedron makes them a suitable support for a Pt monolayer to obtain an active O{sub 2} reduction reaction (ORR) electrocatalyst. The surfactants, used to control size and shape of Pd tetrahedral nanoparticles, are difficult to remove and cause adverse effects on the ORR. We describe a simple and noninvasive method to synthesize high-purity tetrahedral Pd nanocrystals (TH Pd) by combining a hydrothermalmore » route and CO adsorption-induced removal of surfactants. Poly(vinylpyrrolidone) (PVP), used as a protecting and reducing agent in hydrothermal reactions, is strongly bonded to the surface of the resulting nanocrystals. We demonstrate that PVP was displaced efficiently by adsorbed CO. A clean surface was achieved upon CO stripping at a high potential (1.0 V vs RHE). It played a decisive role in improving the activity of the Pt monolayer/TH Pd electrocatalyst for the ORR. Furthermore, the results demonstrate a versatile method for removal of surfactants from various nanoparticles that severely limited their applications.« less

A Phase 1/1b Study Evaluating Trametinib Plus Docetaxel or Pemetrexed in Patients With Advanced Non-Small Cell Lung Cancer.

PubMed

Gandara, David R; Leighl, Natasha; Delord, Jean-Pierre; Barlesi, Fabrice; Bennouna, Jaafar; Zalcman, Gerald; Infante, Jeffrey R; Reckamp, Karen L; Kelly, Karen; Shepherd, Frances A; Mazieres, Julien; Janku, Filip; Gardner, Olivia S; Mookerjee, Bijoyesh; Wu, Yuehui; Cox, Donna S; Schramek, Dan; Peddareddigari, Vijay; Liu, Yuan; D'Amelio, Anthony M; Blumenschein, George

2017-03-01

This two-part study evaluated trametinib, a MEK1/2 inhibitor, in combination with anticancer agents. Inhibition of MEK, a downstream effector of KRAS, demonstrated preclinical synergy with chemotherapy in KRAS-mutant NSCLC cell lines. Part 1 of this study identified recommended phase 2 doses of trametinib combinations. Part 2, reported herein, evaluated the safety, tolerability, pharmacokinetics, and efficacy of trametinib combinations in patients with NSCLC with and without KRAS mutations. Phase 1b evaluated trametinib plus docetaxel with growth factor support (trametinib, 2.0 mg once daily, and docetaxel, 75 mg/m 2 every 3 weeks) or pemetrexed (trametinib, 1.5 mg once daily, and pemetrexed, 500 mg/m 2 every 3 weeks). Eligibility criteria for the expansion cohorts included metastatic NSCLC with measurable disease, known KRAS mutation status, Eastern Cooperative Oncology Group performance status of 1 or lower, and no more than two prior regimens. The primary end point of overall response rate (ORR) was met for both combinations. A confirmed partial response (PR) was observed in 10 of the 47 patients with NSCLC who received trametinib plus docetaxel (21%). The ORR was 18% (four PRs in 22 patients) in those with KRAS wild-type NSCLC versus 24% (six PRs in 25 patients) in those with KRAS-mutant NSCLC. Of the 42 patients with NSCLC treated with trametinib plus pemetrexed, six (14%) had a PR; the ORR was 17% (four of 23) in patients with KRAS-mutated NSCLC versus 11% (two of 19) in KRAS wild-type NSCLC. Adverse events-most commonly diarrhea, nausea, and fatigue-were manageable. Trametinib-plus-chemotherapy combinations were tolerable. Clinical activity exceeding the ORRs previously reported with docetaxel or pemetrexed alone in KRAS-mutated NSCLC and meeting prespecified criteria was observed. Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

[A prospective study of adenosine triphosphate-tumor chemosensitivity assay directed chemotherapy in patients with recurrent ovarian cancer].

PubMed

Gao, Yu-tao; Wu, Ling-ying; Zhang, Wei; Zhao, Dan; Li, Ning; Tian, Hai-mei; Wang, Xiao-bing; Li, Mo; Sun, Yang-chun; Li, Nan; Li, Xiao-guang

2013-05-01

To investigate the efficacy of adenosine triphosphate (ATP)-tumor chemosensitivity assay (TCA) directed chemotherapy in patients with recurrent epithelial ovarian cancer. From August 2010 to June 2012, recurrent epithelial ovarian cancer patients were prospectively enrollmented in Cancer Hospital, Peking Union Medical College,Chinese Academy of Medical Sciences.The entry criteria are as follows: (1) Histologically proven to be epithelial ovarian cancer. (2) Patients of recurrent ovarian cancer with bidimensionally measurable tumor, or ascitic or pleural fluid for testing. (3) Karnofsky performance status > 60. (4) A life expectancy of at least more than 6 months.According to patients desires, they were assigned into two groups: assay-directed therapy group and physician's-choice therapy group, patients' clinical and pathological characteristics, response rate to chemotherapy and progression-free survival (PFS) were compared between two groups. A total of 113 patients with recurrent epithelial ovarian cancer were prospectively enrollmented to assay-directed chemotherapy (n = 56) or physician's-choice chemotherapy (n = 57).There was no difference in median age,types of recurrence, surgical-pathological stage, pathological type, tumor grade, times of recurrence, residual disease at secondary cytoreductive surgery between assay-directed group and physician's-choice group. The overall response rate (ORR) and median PFS in the ATP-TCA group was 66% (37/56) and 7 months, while the ORR in the control group was 46% (26/57, P = 0.037), the median PFS was 4 months (P = 0.040). For platinum-resistant patients, the ORR between ATP-TCA directed chemotherapy 59% (16/27) and control group 25% (7/28) were significantly different (P = 0.010), and the median PFS between two groups were also significantly different (5 months and 2 months, respectively, P = 0.003). ATP-TCA directed chemotherapy could improve ORR and PFS in patients with recurrent epithelial ovarian cancer, especially in platinum-resistant patients.

Evaluation of Overall Response Rate and Progression-Free Survival as Potential Surrogate Endpoints for Overall Survival in Immunotherapy Trials.

PubMed

Mushti, Sirisha L; Mulkey, Flora; Sridhara, Rajeshwari

2018-05-15

Purpose: With the approval of immunotherapies for a variety of indications, methods to assess treatment benefit addressing the response patterns observed are important. We evaluated RECIST criteria-based overall response rate (ORR) and progression-free survival (PFS) as potential surrogate endpoints of overall survival (OS), and explored a modified definition of PFS by altering the threshold percentage determining disease progression to assess the association with survival benefit in immunotherapy trials. Experimental Design: Thirteen randomized, multicenter, active-control trials containing immunotherapeutic agents submitted to the FDA were analyzed. Associations between treatment effects of ORR, PFS, modified PFS, and OS were evaluated at individual and trial levels. Patient-level responder analysis was performed for PFS and OS. Results: The coefficient of determination ( R ²) measured the strength of associations, where values near 1 imply surrogacy and values close to 0 suggest no association. At the trial level, the association between hazard ratios (HR) of PFS and OS was R 2 = 0.1303, and between the odds ratio (OR) of ORR and HR of OS was R 2 = 0.1277. At the individual level, the Spearman rank correlation coefficient between PFS and OS was 0.61. Trial-level associations between modified PFS and OS ranged between 0.07 and 0.1, and individual-level correlations were approximately 0.6. HRs of PFS and OS for responders versus nonresponders were 0.129 [95% confidence interval (CI), 0.11-0.15] and 0.118 (95% CI, 0.11-0.13), respectively. Conclusions: Although responders exhibited longer survival and PFS than nonresponders, the trial-level and individual-level associations were weak between PFS/ORR and OS. Modifications to PFS did not improve associations. Clin Cancer Res; 24(10); 2268-75. ©2018 AACR See related commentary by Korn and Freidlin, p. 2239 . ©2018 American Association for Cancer Research.

Pt-Ni and Pt-Co Catalyst Synthesis Route for Fuel Cell Applications

NASA Technical Reports Server (NTRS)

Firdosy, Samad A.; Ravi, Vilupanur A.; Valdez, Thomas I.; Kisor, Adam; Narayan, Sri R.

2013-01-01

Oxygen reduction reactions (ORRs) at the cathode are the rate-limiting step in fuel cell performance. The ORR is 100 times slower than the corresponding hydrogen oxidation at the anode. Speeding up the reaction at the cathode will improve fuel cell efficiency. The cathode material is generally Pt powder painted onto a substrate (e.g., graphite paper). Recent efforts in the fuel cell area have focused on replacing Pt with Pt-X alloys (where X = Co, Ni, Zr, etc.) in order to (a) reduce cost, and (b) increase ORR rates. One of these strategies is to increase ORR rates by reducing the powder size, which would result in an increase in the surface area, thereby facilitating faster reaction rates. In this work, a process has been developed that creates Pt-Ni or Pt-Co alloys that are finely divided (on the nano scale) and provide equivalent performance at lower Pt loadings. Lower Pt loadings will translate to lower cost. Precursor salts of the metals are dissolved in water and mixed. Next, the salt mixtures are dried on a hot plate. Finally, the dried salt mixture is heattreated in a furnace under flowing reducing gas. The catalyst powder is then used to fabricate a membrane electrode assembly (MEA) for electrochemical performance testing. The Pt- Co catalyst-based MEA showed comparable performance to an MEA fabri cated using a standard Pt black fuel cell catalyst. The main objective of this program has been to increase the overall efficiencies of fuel cell systems to support power for manned lunar bases. This work may also have an impact on terrestrial programs, possibly to support the effort to develop a carbon-free energy source. This catalyst can be used to fabricate high-efficiency fuel cell units that can be used in space as regenerative fuel cell systems, and terrestrially as primary fuel cells. Terrestrially, this technology will become increasingly important when transition to a hydrogen economy occurs.

Metallic State FeS Anchored (Fe)/Fe3O4/N-Doped Graphitic Carbon with Porous Spongelike Structure as Durable Catalysts for Enhancing Bioelectricity Generation.

PubMed

Xu, Xin; Dai, Ying; Yu, Jia; Hao, Liang; Duan, Yaqiang; Sun, Ye; Zhang, Yanhong; Lin, Yuhui; Zou, Jinlong

2017-03-29

The critical issues in practical application of microbial fuel cells (MFCs) for wastewater treatment are the high cost and poor activity and durability of precious metal catalysts. To alleviate the activity loss and kinetic barriers for oxygen reduction reaction (ORR) on cathode, (Fe)/Fe 3 O 4 /FeS/N-doped graphitic carbon ((Fe)/Fe 3 O 4 /FeS/NGC) is prepared as ORR catalyst through a one-step method using waste pomelo skins as carbon source. Various characterization techniques and electrochemical analyses are conducted to illustrate the correlation between structural characteristics and catalytic activity. MFCs with Fe/Fe 3 O 4 /FeS/NGC (900 °C) cathode produces the maximum power density of 930 ± 10 mW m -2 (Pt/C of 489 mW m -2 ) and maintains a good long-term durability, which only declines 18% after 90 day operation. Coulombic efficiency (22.2%) obtained by Fe/Fe 3 O 4 /FeS/NGC (900 °C) cathode is significantly higher than that of Pt/C (17.3%). Metallic state FeS anchored in porous NGC skeleton can boost electron transport through the interconnected channels in spongelike structure to improve catalytic activity. Charge delocalization of C atoms can be strengthened by N atoms incorporation into carbon skeleton, which correspondingly contributes to the O 2 chemisorptions and O-O bond weakening during ORR. Energetically existed active components (Fe and N species) are more efficient than Pt to trap and consume electrons in catalyzing ORR in wastewater containing Pt-poisoning substances (bacterial metabolites). (Fe)/Fe 3 O 4 /FeS/NGC catalysts with the advantages of durable power outputs and environmental-friendly raw material can cover the shortages of Pt/C and provide an outlook for further applications of these catalysts.

Relevance of the Interaction between the M-Phthalocyanines and Carbon Nanotubes in the Electroactivity toward ORR.

PubMed

González-Gaitán, Carolina; Ruiz-Rosas, Ramiro; Morallón, Emilia; Cazorla-Amorós, Diego

2017-10-31

In this work, the influence of the interaction between the iron and cobalt-phthalocyanines (FePc and CoPc) and carbon nanotubes (CNTs) used as support in the electroactivity toward oxygen reduction reaction (ORR) in alkaline media has been investigated. A series of thermal treatments were performed on these materials in order to modify the interaction between the CNTs and the phthalocyanines. The FePc-based catalysts showed the highest activity, with comparable performance to the state-of-the-art Pt-Vulcan catalyst. A heat treatment at 400 °C improved the activity of FePc-based catalysts, while the use of higher temperatures or oxidative atmosphere rendered the decomposition of the macrocyclic compound and consequently the loss of the electrochemical activity of the complex. CoPc-based catalysts performance was negatively affected for all of the tested treatments. Thermogravimetric analyses demonstrated that the FePc was stabilized when loaded onto CNTs, while CoPc did not show such a feature, pointing to a better interaction of the FePc instead of the CoPc. Interestingly, electrochemical measurements demonstrated an improvement of the electron transfer rate in thermally treated FePc-based catalysts. They also allowed us to assess that only 15% of the iron in the catalyst was available for direct electron transfer. This is the same iron amount that remains on the catalyst after a strong acid washing with concentrated HCl (ca. 0.3 wt %), which is enough to deliver a comparable ORR activity. Durability tests confirmed that the catalysts deactivation occurs at a slower rate in those catalysts where FePc is strongly attached to the CNT surface. Thus, the highest ORR activity seems to be provided by those FePc molecules that are strongly attached to the CNT surface, pointing out the relevance of the interaction between the support and the FePc in these catalysts.

Retrospective study of RAS/PIK3CA/BRAF tumor mutations as predictors of response to first-line chemotherapy with bevacizumab in metastatic colorectal cancer patients.

PubMed

Nakayama, Izuma; Shinozaki, Eiji; Matsushima, Tomohiro; Wakatsuki, Takeru; Ogura, Mariko; Ichimura, Takashi; Ozaka, Masato; Takahari, Daisuke; Suenaga, Mitsukuni; Chin, Keisho; Mizunuma, Nobuyuki; Yamaguchi, Kensei

2017-01-09

After analysis of minor RAS mutations (KRAS exon 3, 4/NRAS) in the FIRE-3 and PRIME studies, an expanded range of RAS mutations were established as a negative predictive marker for the efficacy of anti-EGFR antibody treatment. BRAF and PIK3CA mutations may be candidate biomarkers for anti-EGFR targeted therapies. However, it remains unknown whether RAS/PIK3CA/BRAF tumor mutations can predict the efficacy of bevacizumab in metastatic colorectal cancer. We assessed whether selection according to RAS/PIK3CA/BRAF mutational status could be beneficial for patients treated with bevacizumab as first-line treatment for metastatic colorectal cancer. Of the 1001 consecutive colorectal cancer patients examined for RAS, PIK3CA, and BRAF tumor mutations using a multiplex kit (Luminex®), we studied 90 patients who received combination chemotherapy with bevacizumab as first-line treatment for metastatic colorectal cancer. The objective response rate (ORR) and progression-free survival (PFS) were evaluated according to mutational status. The ORR was higher among patients with wild-type tumors (64.3%) compared to those with tumors that were only wild type with respect to KRAS exon 2 (54.8%), and the differences in ORR between patients with wild-type and mutant-type tumors were greater when considering only KRAS exon 2 mutations (6.8%) rather than RAS/PIK3CA/BRAF mutations (18.4%). There were no statistically significant differences in ORR or PFS between all wild-type tumors and tumors carrying any of the mutations. Multivariate analysis revealed that liver metastasis and RAS and BRAF mutations were independent negative factors for disease progression after first-line treatment with bevacizumab. Patient selection according to RAS/PIK3CA/BRAF mutations could help select patients who will achieve a better response to bevacizumab treatment. We found no clinical benefit of restricting combination therapy with bevacizumab for metastatic colorectal cancer patients with EGFR-wild type tumors.

Alectinib in Crizotinib-Refractory ALK-Rearranged Non-Small-Cell Lung Cancer: A Phase II Global Study.

PubMed

Ou, Sai-Hong Ignatius; Ahn, Jin Seok; De Petris, Luigi; Govindan, Ramaswamy; Yang, James Chih-Hsin; Hughes, Brett; Lena, Hervé; Moro-Sibilot, Denis; Bearz, Alessandra; Ramirez, Santiago Viteri; Mekhail, Tarek; Spira, Alexander; Bordogna, Walter; Balas, Bogdana; Morcos, Peter N; Monnet, Annabelle; Zeaiter, Ali; Kim, Dong-Wan

2016-03-01

Crizotinib confers improved progression-free survival compared with chemotherapy in anaplastic lymphoma kinase (ALK)-rearranged non-small-cell lung cancer (NSCLC), but progression invariably occurs. We investigated the efficacy and safety of alectinib, a potent and selective ALK inhibitor with excellent CNS penetration, in patients with crizotinib-refractory ALK-positive NSCLC. Alectinib 600 mg was administered orally twice daily. The primary end point was objective response rate (ORR) by central independent review committee (IRC). Of the 138 patients treated, 84 patients (61%) had CNS metastases at baseline, and 122 were response evaluable (RE) by IRC. ORR by IRC was 50% (95% CI, 41% to 59%), and the median duration of response (DOR) was 11.2 months (95% CI, 9.6 months to not reached). In 96 patients (79%) previously treated with chemotherapy, the ORR was 45% (95% CI, 35% to 55%). Median IRC-assessed progression-free survival for all 138 patients was 8.9 months (95% CI, 5.6 to 11.3 months). CNS disease control rate was 83% (95% CI, 74% to 91%), and the median CNS DOR was 10.3 months (95% CI, 7.6 to 11.2 months). CNS ORR in 35 patients with baseline measurable CNS lesions was 57% (95% CI, 39% to 74%). Of the 23 patients with baseline CNS metastases (measurable or nonmeasurable) and no prior radiation, 10 (43%) had a complete CNS response. At 12 months, the cumulative CNS progression rate (24.8%) was lower than the cumulative non-CNS progression rate (33.2%) for all patients. Common adverse events were constipation (33%), fatigue (26%), and peripheral edema (25%); most were grade 1 to 2. Alectinib is highly active and well tolerated in patients with advanced, crizotinib-refractory ALK-positive NSCLC, including those with CNS metastases. © 2015 by American Society of Clinical Oncology.

TBCRC 019: A Phase II Trial of Nanoparticle Albumin-Bound Paclitaxel with or without the Anti-Death Receptor 5 Monoclonal Antibody Tigatuzumab in Patients with Triple-Negative Breast Cancer.

PubMed

Forero-Torres, Andres; Varley, Katherine E; Abramson, Vandana G; Li, Yufeng; Vaklavas, Christos; Lin, Nancy U; Liu, Minetta C; Rugo, Hope S; Nanda, Rita; Storniolo, Anna M; Traina, Tiffany A; Patil, Sujata; Van Poznak, Catherine H; Nangia, Julie R; Irvin, William J; Krontiras, Helen; De Los Santos, Jennifer F; Haluska, Paul; Grizzle, William; Myers, Richard M; Wolff, Antonio C

2015-06-15

Tigatuzumab (TIG), an agonistic anti-DR5 antibody, triggers apoptosis in DR5(+) human tumor cells without crosslinking. TIG has strong in vitro/in vivo activity against basal-like breast cancer cells enhanced by chemotherapy agents. This study evaluates activity of TIG and chemotherapy in patients with metastatic triple-negative breast cancer (TNBC). Randomized 2:1 phase II trial of albumin-bound paclitaxel (nab-PAC) ± TIG in patients with TNBC stratified by prior chemotherapy. Patients received nab-PAC weekly × 3 ± TIG every other week, every 28 days. Primary objective was within-arm objective response rate (ORR). Secondary objectives were safety, progression-free survival (PFS), clinical benefit, and TIG immunogenicity. Metastatic research biopsies were required. Among 64 patients (60 treated; TIG/nab-PAC n = 39 and nab-PAC n = 21), there were 3 complete remissions (CR), 8 partial remissions (PR; 1 almost CR), 11 stable diseases (SD), and 17 progressive diseases (PD) in the TIG/nab-PAC arm (ORR, 28%), and no CRs, 8 PRs, 4 SDs, and 9 PDs in the nab-PAC arm (ORR, 38%). There was a numerical increase in CRs and several patients had prolonged PFS (1,025+, 781, 672, 460, 334) in the TIG/nab-PAC arm. Grade 3 toxicities were 28% and 29%, respectively, with no grade 4-5. Exploratory analysis suggests an association of ROCK1 gene pathway activation with efficacy in the TIG/nab-PAC arm. ORR and PFS were similar in both. Preclinical activity of TIG in basal-like breast cancer and prolonged PFS in few patients in the combination arm support further investigation of anti-DR5 agents. ROCK pathway activation merits further evaluation. ©2015 American Association for Cancer Research.

Cross-Organizational Knowledge Sharing: Information Reuse in Small Organizations

ERIC Educational Resources Information Center

White, Kevin Forsyth

2010-01-01

Despite the potential value of leveraging organizational memory and expertise, small organizations have been unable to capitalize on its promised value. Existing solutions have largely side-stepped the unique needs of these organizations, which are relegated to systems designed to take advantage of large pools of experts or to use Internet sources…

Spectroscopic insights into the nature of active sites in iron–nitrogen–carbon electrocatalysts for oxygen reduction in acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Qingying; Ramaswamy, Nagappan; Tylus, Urszula

Developing efficient and inexpensive catalysts for the sluggish oxygen reduction reaction (ORR) constitutes one of the grand challenges in the fabrication of commercially viable fuel cell devices and metal–air batteries for future energy applications. Despite recent achievements in designing advanced Pt-based and Pt-free catalysts, current progress primarily involves an empirical approach of trial-and-error combination of precursors and synthesis conditions, which limits further progress. Rational design of catalyst materials requires proper understanding of the mechanistic origin of the ORR and the underlying surface properties under operating conditions that govern catalytic activity. Herein, several different groups of iron-based catalysts synthesized via differentmore » methods and/or precursors were systematically studied by combining multiple spectroscopic techniques under ex situ and in situ conditions in an effort to obtain a comprehensive understanding of the synthesis-products correlations, nature of active sites, and the reaction mechanisms. These catalysts include original macrocycles, macrocycle-pyrolyzed catalysts, and Fe-N–C catalysts synthesized from individual Fe, N, and C precursors including polymer-based catalysts, metal organic framework (MOF)-based catalysts, and sacrificial support method (SSM)-based catalysts. The latter group of catalysts is most promising as not only they exhibit exceptional ORR activity and/or durability, but also the final products are controllable. We show that the high activity observed for most pyrolyzed Fe-based catalysts can mainly be attributed to a single active site: non-planar Fe–N 4 moiety embedded in distorted carbon matrix characterized by a high potential for the Fe 2+/3+ redox transition in acidic electrolyte/environment. The high intrinsic ORR activity, or turnover frequency (TOF), of this site is shown to be accounted for by redox catalysis mechanism that highlights the dominant role of the site-blocking effect. Moreover, a highly active MOF-based catalyst without Fe–N moieties was developed, and the active sites were identified as nitrogen-doped carbon fibers with embedded iron particles that are not directly involved in the oxygen reduction pathway. The high ORR activity and durability of catalysts involving this second site, as demonstrated in fuel cell, are attributed to the high density of active sites and the elimination or reduction of Fenton-type processes. The latter are initiated by hydrogen peroxide but are known to be accelerated by iron ions exposed to the surface, resulting in the formation of damaging free-radicals.« less

Safety and efficacy of targeted hyperthermia treatment utilizing gold nanorod therapy in spontaneous canine neoplasia.

PubMed

Schuh, Elizabeth M; Portela, Roberta; Gardner, Heather L; Schoen, Christian; London, Cheryl A

2017-10-02

Hyperthermia is an established anti-cancer treatment but is limited by tolerance of adjacent normal tissues. Parenteral administration of gold nanorods (NRs) as a photosensitizer amplifies the effects of hyperthermia treatment while sparing normal tissues. This therapy is well tolerated and has demonstrated anti-tumor effects in mouse models. The purpose of this phase 1 study was to establish the safety and observe the anti-tumor impact of gold NR enhanced (plasmonic) photothermal therapy (PPTT) in client owned canine patients diagnosed with spontaneous neoplasia. Seven dogs underwent gold NR administration and subsequent NIR PPTT. Side effects were mild and limited to local reactions to NIR laser. All of the dogs enrolled in the study experienced stable disease, partial remission or complete remission. The overall response rate (ORR) was 28.6% with partial or complete remission of tumors at study end. PPTT utilizing gold nanorod therapy can be safely administered to canine patients. Further studies are needed to determine the true efficacy in a larger population of canine cancer patients and to and identify those patients most likely to benefit from this therapy.

Graphene oxide nanoplatforms to enhance catalytic performance of iron phthalocyanine for oxygen reduction reaction in bioelectrochemical systems

NASA Astrophysics Data System (ADS)

Costa de Oliveira, Maida Aysla; Mecheri, Barbara; D'Epifanio, Alessandra; Placidi, Ernesto; Arciprete, Fabrizio; Valentini, Federica; Perandini, Alessando; Valentini, Veronica; Licoccia, Silvia

2017-07-01

We report the development of electrocatalysts based on iron phthalocyanine (FePc) supported on graphene oxide (GO), obtained by electrochemical oxidation of graphite in aqueous solution of LiCl, LiClO4, and NaClO4. Structure, surface chemistry, morphology, and thermal stability of the prepared materials were investigated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic force microscopy (AFM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The catalytic activity toward oxygen reduction reaction (ORR) at neutral pH was evaluated by cyclic voltammetry. The experimental results demonstrate that the oxidation degree of GO supports affects the overall catalytic activity of FePc/GO, due to a modulation effect of the interaction between FePc and the basal plane of GO. On the basis of electrochemical, spectroscopic, and morphological investigations, FePc/GO_LiCl was selected to be assembled at the cathode side of a microbial fuel cell prototype, demonstrating a good electrochemical performance in terms of voltage and power generation.

Oxygen reduction reaction (ORR) on mixed oxy-nitride non-noble catalyst: Ab-initio simulation, elaboration and characterization

NASA Astrophysics Data System (ADS)

Seifitokaldani, Ali

In this project, titanium oxy-nitride (TiOxN y) has been studied as a new non-noble electrocatalyst for the oxygen reduction reaction (ORR). A comprehensive comparison between four different sol-gel methods was carried out to evaluate the physicochemical and electrochemical properties of the produced electro-catalysts. Among them, a new urea-based sol-gel method (simply called U method) is introduced to prepare TiOxNy at a fairly low temperature and duration, with higher electro-catalytic activity for the ORR. The prepared electro-catalysts with different N/O ratios showed different properties from a less conductive behavior in oxygen-rich (low N/O ratio) materials to more conductive electro-catalyst behavior in nitrogen-rich (high N/O ratio) oxy-nitrides, respectively. Generally, electro-catalysts prepared by the U method had more titanium nitride in their structures than the electro-catalysts prepared by the other methods. Nevertheless, heat treatment had a key role in this phase transferring from having high oxide structure to high nitride structure. According to the elemental analysis done by energy dispersive spectroscopy (EDS), nitrogen percentage in the bulk material increased from 9 to 24 percent by increasing the temperature from 700 to 1100 °C, while the oxygen percentage was decreasing inversely. In addition, based on the X-ray diffraction (XRD) data, in the case of U method, the TiN characteristic peaks were obvious, even at lower temperatures. Increasing the temperature also made the peaks much sharper indicating the growth of the crystallite size. The calculated crystallite size showed the crystallite size of samples prepared by U method (20 to 40 nm) was almost in the same range of the TiN crystallite size, but the crystallite size of the samples prepared by the other sol-gel methods (40 to 60 nm) was in the same range of the TiO2 crystallite size. Scanning electron microscopy (SEM) and B.E.T. surface area analyzer were used to evaluate the particle size and surface area of different samples, respectively. They indicated a smaller particle size and a higher surface area in the electro-catalysts produced by the U method. Besides the aforementioned physicochemical characterizations, cyclic voltammetry (CV), polarization, and electrochemical impedance spectroscopy (EIS) were used to evaluate the electrochemical properties of the electro-catalysts. Obtained Tafel slope, exchange current density and onset potential revealed that the electro-catalyst prepared by the U method which was annealed at 1100 °C, had the best electro-catalytic activity among all other samples with Tafel slope of -203 mV/decade, exchange current density around 4E-04 mA/mg and the onset potential close to 0.8 volt vs. NHE (normal hydrogen electrode). EIS measurements also supported this assertion through revealing the highest specific capacitance (˜ 3.3 F/g). This result was in agreement with the highest B.E.T. surface area and the lowest charge transfer resistance exhibited by this electro-catalyst among the other samples. Stability is one of the determinant factors in selecting an electro-catalyst for the ORR. In this regard, ICP-TOF-MS was used to evaluate the chemical stability of the prepared electro-catalysts under corrosive acidic environment, by measuring the concentration of the dissolved titanium after a certain time. Heretofore, measuring the dissolved metal concentration by ICP-TOF-MS was done just to evaluate its chemical stability. However, in this project this technique was also used during the CV, to evaluate the electro-catalyst's electrochemical stability as well, which is more realistic and similar to the PEMFC's working condition. Stability of the best electrocatalyst with the highest catalytic activity (prepared by the U method) was better than the commercially used Pt/C electro-catalyst, both chemically and electrochemically. Electrochemical stability of the prepared electro-catalysts has also been studied at a high oxidizing potential (more than 2 volts vs. NHE). X-ray Photoelectron Spectroscopy (XPS) showed that the nitrogen amount on the surface of the electro-catalyst decreased from 11 % before the oxidation to 5 % after the oxidation, whereas the catalytic activity for the ORR decreased after the oxidation. Thus, decreasing the titanium nitride's amount in the titanium oxy-nitride surface reduced its catalytic activity. In the second phase of this project, electro-catalytic activity of the titanium nitride for the ORR was investigated via a density functional theory (DFT) computation. To the best of our knowledge, there is no theoretical and computational quantum chemistry study of the transition metal's nitride as the electro-catalyst in PEM fuel cells. ORR was considered to take place in three different sequential steps namely oxygen adsorption, hydroxide production and water desorption. Based on the XRD results, TiN(111) and TiN(200) were considered as the two major facets of the TiN. Simulation was done by the Vienna ab initio Simulation Package (VASP) based on the Plane-Wave basis sets and periodic boundary condition, while the PBE exchangecorrelational functional was used to describe the interactions among electrons. Comparing the adsorption energies proved existence of a strong dissociative adsorption of oxygen on the TiN(111) regardless of the adsorption sites. However, because of a relatively strong OH adsorption, TiN(111) loses the active sites to proceed the ORR, while on the TiN(200) surface, water production and desorption came about easily. Electron density of states (DOS) was obtained to calculate the d-band center and fractional filling in different situations. Considering two possible bridge and top adsorption sites on the TiN(200), these information indicated the hydroxide production and water desorption as the rate determining steps for the ORR in bridge and top sites, respectively. Therefore, it was shown that the TiN, specially TiN(200) had exhibited good electro-catalytic activity for the ORR. Losing this TiN amount from the titanium oxy-nitride's surface might be responsible for the decrease of the electro-catalytic activity of the titanium oxy-nitride for the ORR.

The troublesome birth of hydrodynamic stability theory: Sommerfeld and the turbulence problem

NASA Astrophysics Data System (ADS)

Eckert, M.

2010-07-01

More than a hundred years ago William McFadden Orr and Arnold Sommerfeld conceived an approach to account for the transition from laminar to turbulent flow in terms of hydrodynamic stability theory. But the “turbulence problem”, as this challenge became notoriously famous, could not be solved by this method. By 1920, it was widely recognized as an outstanding riddle. Although famous theoretical physicists like Werner Heisenberg dedicated a considerable effort to this problem, the “Orr-Sommerfeld method” has never found the attention of historians of science. This article describes its early perception and development in Germany, and how the “turbulence problem” reached center stage after the First World war as a major challenge for theorists with different perspectives.

Trend in the Catalytic Activity of Transition Metals for the Oxygen Reduction Reaction by Lithium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dathar, Gopi Krishna Phani; Shelton Jr, William Allison; Xu, Ye

2012-01-01

Periodic density functional theory (DFT) calculations indicate that the intrinsic activity of Au, Ag, Pt, Pd, Ir, and Ru for the oxygen reduction reaction by Li (Li-ORR) forms a volcano-like trend with respect to the adsorption energy of oxygen, with Pt and Pd being the most active. The trend is based on two mechanisms: the reduction of molecular O{sub 2} on Au and Ag and of atomic O on the remaining metals. Step edges are found to be more active for catalyzing the Li-ORR than close-packed surfaces. Our findings identify important considerations in the design of catalyst-promoted air cathodes formore » nonaqueous Li-air batteries.« less

Surface tailored single walled carbon nanotubes as catalyst support for direct methanol fuel cell

NASA Astrophysics Data System (ADS)

Kireeti, Kota V. M. K.; Jha, Neetu

2017-10-01

A strategy for tuning the surface property of Single Walled Carbon Nanotubes (SWNTs) for enhanced methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) along with methanol tolerance is presented. The surface functionality is tailored using controlled acid and base treatment. Acid treatment leads to the attachment of carboxylic carbon (CC) fragments to SWNT making it hydrophilic (P3-SWNT). Base treatment of P3-SWNT with 0.05 M NaOH reduces the CCs and makes it hydrophobic (P33-SWNT). Pt catalyst supported on the P3-SWNT possesses enhanced MOR whereas that supported on P33-SWNT not only enhances ORR kinetics but also possess good tolerance towards methanol oxidation as verified by the electrochemical technique.

A high-performance mesoporous carbon supported nitrogen-doped carbon electrocatalyst for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Xu, Jingjing; Lu, Shiyao; Chen, Xu; Wang, Jianan; Zhang, Bo; Zhang, Xinyu; Xiao, Chunhui; Ding, Shujiang

2017-12-01

Investigating low-cost and highly active electrocatalysts for oxygen reduction reactions (ORR) is of crucial importance for energy conversion and storage devices. Herein, we design and prepare mesoporous carbon supported nitrogen-doped carbon by pyrolysis of polyaniline coated on CMK-3. This electrocatalyst exhibits excellent performance towards ORR in alkaline media. The optimized nitrogen-doped mesoporous electrocatalyst show an onset potential (E onset) of 0.95 V (versus reversible hydrogen electrode (RHE)) and half-wave potential (E 1/2) of 0.83 V (versus RHE) in 0.1 M KOH. Furthermore, the as-prepared catalyst presents superior durability and methanol tolerance compared to commercial Pt/C indicating its potential applications in fuel cells and metal-air batteries.

Egg derived nitrogen-self-doped carbon/carbon nanotube hybrids as noble-metal-free catalysts for oxygen reduction

NASA Astrophysics Data System (ADS)

Zhang, Jian; Wu, Siyu; Chen, Xu; Pan, Mu; Mu, Shichun

2014-12-01

Currently, the development of nitrogen (N) doped carbon based non-precious metal ORR catalysts has become one of the most attractive topics in low temperature fuel cells. Here, we demonstrate a green synthesis route of N-self-doped carbon materials by using eggs as N sources combining with iron sources and multi-walled carbon nanotubes (CE-Fe-MWNT). After carbonized, such hybrid materials possess an outstanding electrocatalytic activity towards ORR comparable to the commercial Pt/C catalyst in alkaline media, and both superior stability and fuel (methanol and CO) tolerance than the commercial Pt/C catalyst, which provide a promising alternative to noble metal catalysts by using abundant natural biological resources.

pH matters: The influence of the catalyst ink on the oxygen reduction activity determined in thin film rotating disk electrode measurements

NASA Astrophysics Data System (ADS)

Inaba, Masanori; Quinson, Jonathan; Arenz, Matthias

2017-06-01

We investigated the influence of the ink properties of proton exchange membrane fuel cell (PEMFC) catalysts on the oxygen reduction reaction (ORR) activity determined in thin film rotating disk electrode (TF-RDE) measurements. It was found that the adaption of a previously reported ink recipe to home-made catalysts does not lead to satisfying results, although reported work could be reproduced using commercial catalyst samples. It is demonstrated that the pH of the catalyst ink, which has not been addressed in previous TF-RDE studies, is an important parameter that needs to be carefully controlled to determine the intrinsic ORR activity of high surface area catalysts.

Electrochemical investigations of Co3Fe-RGO as a bifunctional catalyst for oxygen reduction and evolution reactions in alkaline media

NASA Astrophysics Data System (ADS)

Kumar, Surender; Kumar, Divyaratan; Kishore, Brij; Ranganatha, Sudhakar; Munichandraiah, Nookala; Venkataramanan, Natarajan S.

2017-10-01

Nanoparticles of Co3Fe alloy is prepared on reduced graphene oxide (RGO) sheets by modified polyol method. Synthesized alloy particles are characterized by various physicochemical techniques. TEM and SEM pictures showed homogeneously dispersed alloy nanoparticles on the RGO sheets. Electrochemistry of alloy nanoparticles is investigated in alkaline medium. The result shows that oxygen evaluation reaction (OER) activity of Co3Fe-RGO is higher than Pt-black particles. RDE studies in alkaline medium shows that oxygen reduction reaction (ORR) follow four electron pathway. It is suggest that Co3Fe-RGO is an efficient non-precious catalyst for oxygen (ORR/OER) reactions in alkaline electrolyte for PEMFC applications.

Construction Foundation Report for Cuchillo Negro Dam, New Mexico. Volume 2. Appendix B, Appendix C, and Appendix D

DTIC Science & Technology

1992-12-01

Orr. 15 dog - 49 - Irr.-, frac. op. hor. 50-7 CD 50.4 50.4- P-3 Irr. frc p o.Ran 10.2 R:C-. 10.2 -T- -intensely fr-ac. Loss 0.0 -HB U.L. 0.0 HIDrill...unwea. f. to milcro xin. med.RO 62.Go to thick bdd. fos. w/ oct. sht Ielaminae, Gry V/ red tint DIP- L./o, orr. C 265. Bdd. Pig. op, 0 dog . C 265...Vert, frac. err. Cot. hid. 63 - dd. Pigs. op. 5-10 dog , 58.6 59 -CD *59.3 59.3 P-10 Box Ren 10.2 6 Rec. 10.0 ldd.Ptg. IL.. 10-13 do%. 4 Loss 0.2 Idd.Ptq

Enhanced oxygen reduction activity and solid oxide fuel cell performance with a nanoparticles-loaded cathode.

PubMed

Zhang, Xiaomin; Liu, Li; Zhao, Zhe; Tu, Baofeng; Ou, Dingrong; Cui, Daan; Wei, Xuming; Chen, Xiaobo; Cheng, Mojie

2015-03-11

Reluctant oxygen-reduction-reaction (ORR) activity has been a long-standing challenge limiting cell performance for solid oxide fuel cells (SOFCs) in both centralized and distributed power applications. We report here that this challenge has been tackled with coloading of (La,Sr)MnO3 (LSM) and Y2O3 stabilized zirconia (YSZ) nanoparticles within a porous YSZ framework. This design dramatically improves ORR activity, enhances fuel cell output (200-300% power improvement), and enables superior stability (no observed degradation within 500 h of operation) from 600 to 800 °C. The improved performance is attributed to the intimate contacts between nanoparticulate YSZ and LSM particles in the three-phase boundaries in the cathode.

Adjusted Indirect Comparison Using Propensity Score Matching of Osimertinib to Platinum-Based Doublet Chemotherapy in Patients with EGFRm T790M NSCLC Who Have Progressed after EGFR-TKI.

PubMed

Mann, Helen; Andersohn, Frank; Bodnar, Carolyn; Mitsudomi, Tetsuya; Mok, Tony S K; Yang, James Chih-Hsin; Hoyle, Christopher

2018-04-01

An adjusted indirect comparison was conducted to assess efficacy outcomes, particularly overall survival (OS), of osimertinib versus platinum-based doublet chemotherapy in patients with epidermal growth factor receptor-mutated (EGFRm) T790M mutation-positive non-small-cell lung cancer (NSCLC) who had progressed following an EGFR tyrosine kinase inhibitor (TKI). Analysis of treatment effect from two separate trials had the potential to more accurately estimate the magnitude of OS benefit due to absence of confounding due to treatment switching from the control arm to the osimertinib arm of the ongoing randomized control trial, AURA3. Two non-randomized individual datasets were compared: pooled patients from the AURA extension and AURA2 trials (osimertinib 80 mg, n = 405, with a confirmed T790M mutation using tissue samples), and patients from the control arm of the IMPRESS study (platinum-based doublet chemotherapy, n = 61, with a confirmed T790M mutation using plasma circulating tumour DNA [ctDNA]). A propensity score-based approach was used to account for differences in baseline demographics and disease characteristics. After adjustment for baseline differences between the two groups, osimertinib demonstrated a statistically significant improvement in progression-free survival (PFS) versus platinum-based doublet chemotherapy (hazard ratio [HR] = 0.278, 95% confidence interval [CI] 0.188-0.409, p < 0.0001; median PFS 10.9 vs. 5.3 months). Improvements were also observed for objective response rate (ORR) and disease control rate (DCR) (ORR: 64.3 vs. 33.3%; odds ratio [OR] = 5.31, 95% CI 2.47-11.40, p < 0.001; DCR: 92.1 vs. 75.0%; OR = 4.72, 95% CI 1.92-11.58, p < 0.001). Similar results were obtained for patients who received osimertinib as second-line treatment only. A statistically significant improvement in OS was observed for the osimertinib group (HR = 0.412, 95% CI 0.273-0.622, p < 0.0001). Median OS for osimertinib was not reached. In this indirect comparison, osimertinib showed a statistically significant improvement in efficacy outcomes versus platinum-based doublet chemotherapy in patients with EGFRm T790M NSCLC who had progressed after EGFR-TKI therapy.

Molten Pool Behavior and Mechanical Properties of Pulsed Current Double-Sided Synchronization GTA Welded Fe-18Cr-17Mn-Ni-N

NASA Astrophysics Data System (ADS)

Qiang, Wei; Wang, Kehong; Feng, Yuehai; Chen, Jiahe

2017-02-01

Double-sided synchronization vertical gas tungsten arc welding (DSSVW) procedure was used to weld high-nitrogen low-nickel stainless steel Fe-18Cr-17Mn-Ni-N without groove and filler wire. First, the molten pool behaviors and appearances of pulsed current DSSVW (PC-DSSVW) and constant current DSSVW (CC-DSSVW) were comparatively analyzed. The periodic variation occurs in the width of both the anode region of the arc and the molten pool tail during PC-DSSVW, while the contact angle first increases and then decreases, and both the width of the anode region and the length of arc plume increase progressively in CC-DSSVW. It is found that the weld appearance of PC-DSSVW is superior to that of CC-DSSVW. Second, the forces of the DSSVW molten pool were analyzed. The result indicates that the molten pool of the DSSVW procedure is in a state of unstable equilibrium, and it will easily lose balance after being disturbed, resulting in the asymmetrical weld or hump bead. Third, the PC-DSSVW experiments at various welding speeds were conducted to study the influence of welding speed on the weld profile, microstructure, tensile strength and impact toughness. Furthermore, the solidification mode of Fe-18Cr-17Mn-Ni-N was predicted to help determine the microstructure of the welded joint. Results indicate that the weld width, weld reinforcement and melting area all increase with decreasing welding speed, and Fe-18Cr-17Mn-Ni-N solidifies as A mode. The microstructure of the base metal (BM) and heat-affected zone (HAZ) is equiaxed austenite and that of the fusion zone (FZ) is austenite dendrite with some chromium carbides dispersed in the grain boundary; with decreasing welding speed, grains become coarse. The maximum tensile strength (UTS) and elongation of PC-DSSVW joint are 860 MPa and 8.1%, and the elongation decreases dramatically with decreasing welding speed. The impact toughness decreases substantially compared to the BM, achieving 48.2% of the BM.

Efficacy and side-effect profiles of lactulose, docusate sodium, and sennosides compared to PEG in opioid-induced constipation: a systematic review.

PubMed

Ruston, Teresa; Hunter, Kathleen; Cummings, Greta; Lazarescu, Adriana

2013-01-01

Opioid-induced constipation (OIC) is a side effect of opioid therapy that can affect quality of life, adherence to treatment, and morbidity and possibly mortality. To investigate whether docusate sodium, sennosides, and lactulose have equal efficacy and side effect profiles compared to PEG in the management of OIC in adults. A systematic review was undertaken. Randomized controlled trials of adults taking opioids for cancer or non-cancer pain were considered if they met inclusion criteria. Statistical pooling was not possible as no studies met inclusion criteria. Large, well-powered, randomized controlled trials are feasible. Standard definitions of OIC would assist with the execution of these studies and contribute to their internal and external validity. Further research is strongly encouraged.

Photolytic removal of DBPs by medium pressure UV in swimming pool water.

PubMed

Hansen, Kamilla M S; Zortea, Raissa; Piketty, Aurelia; Vega, Sergio Rodriguez; Andersen, Henrik Rasmus

2013-01-15

Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported to be found in swimming pool water: chloroform, bromodichloromethane, dibromochloromethane, bromoform, dichloroacetonitrile, bromochloroacetonitrile, dibromoacetronitrile, trichloroacetonitrile, trichloronitromethane, dichloropropanone, trichloropropanone, and chloral hydrate. First order photolysis constants ranged 26-fold from 0.020 min(-1) for chloroform to 0.523 min(-1) for trichloronitromethane. The rate constants generally increased with bromine substitution. Using the UV removal of combined chlorine as an actinometer, the rate constants were recalculated to actual treatment doses of UV applied in a swimming pool. In an investigated public pool the UV dose was equivalent to an applied electrical energy of 1.34 kWh m(-3) d(-1) and the UV dose required to removed 90% of trichloronitromethane was 0.4 kWh m(-3) d(-1), while 2.6 kWh m(-3) d(-1) was required for chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes ranged from 0.6 to 3.1 kWh m(-3) d(-1). It was predicted thus that a beneficial side-effect of applying UV for removing combined chlorine from the pool water could be a significant removal of trichloronitromethane, chloral hydrate and the bromine containing haloacetonitriles and trihalomethanes. Copyright © 2012 Elsevier B.V. All rights reserved.

Electrocatalytic N-Doped Graphitic Nanofiber - Metal/Metal Oxide Nanoparticle Composites.

PubMed

Tang, Hongjie; Chen, Wei; Wang, Jiangyan; Dugger, Thomas; Cruz, Luz; Kisailus, David

2018-03-01

Carbon-based nanocomposites have shown promising results in replacing commercial Pt/C as high-performance, low cost, nonprecious metal-based oxygen reduction reaction (ORR) catalysts. Developing unique nanostructures of active components (e.g., metal oxides) and carbon materials is essential for their application in next generation electrode materials for fuel cells and metal-air batteries. Herein, a general approach for the production of 1D porous nitrogen-doped graphitic carbon fibers embedded with active ORR components, (M/MO x , i.e., metal or metal oxide nanoparticles) using a facile two-step electrospinning and annealing process is reported. Metal nanoparticles/nanoclusters nucleate within the polymer nanofibers and subsequently catalyze graphitization of the surrounding polymer matrix and following oxidation, create an interconnected graphite-metal oxide framework with large pore channels, considerable active sites, and high specific surface area. The metal/metal oxide@N-doped graphitic carbon fibers, especially Co 3 O 4 , exhibit comparable ORR catalytic activity but superior stability and methanol tolerance versus Pt in alkaline solutions, which can be ascribed to the synergistic chemical coupling effects between Co 3 O 4 and robust 1D porous structures composed of interconnected N-doped graphitic nanocarbon rings. This finding provides a novel insight into the design of functional electrocatalysts using electrospun carbon nanomaterials for their application in energy storage and conversion fields. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trends in Adsorption Energies of the Oxygenated Species on Single Platinum Atom Embedded in Carbon Nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siahrostami, Samira; Li, Guo-Ling; Nørskov, Jens K.

Herein we study the effect of strain on the catalytic activity of different Pt-doped single wall metallic carbon nanotubes (SWCNT) towards the oxygen reduction reaction (ORR). We consider the possibility of the Pt-doped at single vacancy inside the SWCNT to investigate the effect of confinement on the reaction mechanism. Density functional theory calculations indicate that for the SWCNTs with tube diameters below 7 Å, the strain energy varies significantly influencing the adsorption energies of the key intermediates of the ORR reaction. For the SWCNTs with tube diameters above 7 Å, on the other hand, both the calculated strain and themore » adsorption energies are almost constant. We furthermore find that the adsorption energies are strongly affected by confinement effects as shown for Pt-doped systems that are located inside the SWCNT. We show that the Pt-doped at single vacancy of the SWCNT strongly binds the oxygenated species under ORR potentials and therefore the active species is covered by oxo- or hydroxo group. Because the presence of Pt atoms doped at the single and double vacancies of the SWCNT is equivalently probable we also studied the Pt-doped at double vacancy. We find that the most active motif is the Pt-doped at double vacancy of SWCNT with 0.24V overpotenital.« less

Highly efficient transition metal and nitrogen co-doped carbide-derived carbon electrocatalysts for anion exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Ratso, Sander; Kruusenberg, Ivar; Käärik, Maike; Kook, Mati; Puust, Laurits; Saar, Rando; Leis, Jaan; Tammeveski, Kaido

2018-01-01

The search for an efficient electrocatalyst for oxygen reduction reaction (ORR) to replace platinum in fuel cell cathode materials is one of the hottest topics in electrocatalysis. Among the many non-noble metal catalysts, metal/nitrogen/carbon composites made by pyrolysis of cheap materials are the most promising with control over the porosity and final structure of the catalyst a crucial point. In this work we show a method of producing a highly active ORR catalyst in alkaline media with a controllable porous structure using titanium carbide derived carbon as a base structure and dicyandiamide along with FeCl3 or CoCl2 as the dopants. The resulting transition metal-nitrogen co-doped carbide derived carbon (M/N/CDC) catalyst is highly efficient for ORR electrocatalysis with the activity in 0.1 M KOH approaching that of commercial 46.1 wt.% Pt/C. The catalyst materials are also investigated by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy to characterise the changes in morphology and composition causing the raise in electrochemical activity. MEA performance of M/N/CDC cathode materials in H2/O2 alkaline membrane fuel cell is tested with the highest power density reached being 80 mW cm-2 compared to 90 mW cm-2 for Pt/C.

FDA Approval: Ibrutinib for Patients with Previously Treated Mantle Cell Lymphoma and Previously Treated Chronic Lymphocytic Leukemia.

PubMed

de Claro, R Angelo; McGinn, Karen M; Verdun, Nicole; Lee, Shwu-Luan; Chiu, Haw-Jyh; Saber, Haleh; Brower, Margaret E; Chang, C J George; Pfuma, Elimika; Habtemariam, Bahru; Bullock, Julie; Wang, Yun; Nie, Lei; Chen, Xiao-Hong; Lu, Donghao Robert; Al-Hakim, Ali; Kane, Robert C; Kaminskas, Edvardas; Justice, Robert; Farrell, Ann T; Pazdur, Richard

2015-08-15

On November 13, 2013, the FDA granted accelerated approval to ibrutinib (IMBRUVICA capsules; Pharmacyclics, Inc.) for the treatment of patients with mantle cell lymphoma (MCL) who have received at least one prior therapy. On February 12, 2014, the FDA granted accelerated approval for the treatment of patients with chronic lymphocytic leukemia (CLL) who have received at least one prior therapy. Ibrutinib is a first-in-class Bruton's tyrosine kinase (BTK) inhibitor that received all four expedited programs of the FDA: Fast-Track designation, Breakthrough Therapy designation, Priority Review, and Accelerated Approval. Both approvals were based on overall response rate (ORR) and duration of response (DOR) in single-arm clinical trials in patients with prior treatment. In MCL (N = 111), the complete and partial response rates were 17.1% and 48.6%, respectively, for an ORR of 65.8% [95% confidence interval (CI), 56.2%-74.5%]. The median DOR was 17.5 months (95% CI, 15.8-not reached). In CLL (N = 48), the ORR was 58.3% (95% CI, 43.2%-72.4%), and the DOR ranged from 5.6 to 24.2 months. The most common adverse reactions (≥ 30% in either trial) were thrombocytopenia, diarrhea, neutropenia, bruising, upper respiratory tract infection, anemia, fatigue, musculoskeletal pain, peripheral edema, and nausea. ©2015 American Association for Cancer Research.

O-, N-Atoms-Coordinated Mn Cofactors within a Graphene Framework as Bioinspired Oxygen Reduction Reaction Electrocatalysts.

PubMed

Yang, Yang; Mao, Kaitian; Gao, Shiqi; Huang, Hao; Xia, Guoliang; Lin, Zhiyu; Jiang, Peng; Wang, Changlai; Wang, Hui; Chen, Qianwang

2018-05-28

Manganese (Mn) is generally regarded as not being sufficiently active for the oxygen reduction reaction (ORR) compared to other transition metals such as Fe and Co. However, in biology, manganese-containing enzymes can catalyze oxygen-evolving reactions efficiently with a relative low onset potential. Here, atomically dispersed O and N atoms coordinated Mn active sites are incorporated within graphene frameworks to emulate both the structure and function of Mn cofactors in heme-copper oxidases superfamily. Unlike previous single-metal catalysts with general M-N-C structures, here, it is proved that a coordinated O atom can also play a significant role in tuning the intrinsic catalytic activities of transition metals. The biomimetic electrocatalyst exhibits superior performance for the ORR and zinc-air batteries under alkaline conditions, which is even better than that of commercial Pt/C. The excellent performance can be ascribed to the abundant atomically dispersed Mn cofactors in the graphene frameworks, confirmed by various characterization methods. Theoretical calculations reveal that the intrinsic catalytic activity of metal Mn can be significantly improved via changing local geometry of nearest coordinated O and N atoms. Especially, graphene frameworks containing the Mn-N 3 O 1 cofactor demonstrate the fastest ORR kinetics due to the tuning of the d electronic states to a reasonable state. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tunable Bifunctional Activity of Mnx Co3-x O4 Nanocrystals Decorated on Carbon Nanotubes for Oxygen Electrocatalysis.

PubMed

Zhao, Tingting; Gadipelli, Srinivas; He, Guanjie; Ward, Matthew J; Do, David; Zhang, Peng; Guo, Zhengxiao

2018-04-25

Noble-metal-free electrocatalysts are attractive for cathodic oxygen catalysis in alkaline membrane fuel cells, metal-air batteries, and electrolyzers. However, much of the structure-activity relationship is poorly understood. Herein, the comprehensive development of manganese cobalt oxide/nitrogen-doped multiwalled carbon nanotube hybrids (Mn x Co 3-x O 4 @NCNTs) is reported for highly reversible oxygen reduction and evolution reactions (ORR and OER, respectively). The hybrid structures are rationally designed by fine control of surface chemistry and synthesis conditions, including tuning of functional groups at surfaces, congruent growth of nanocrystals with controllable phases and particle sizes, and ensuring strong coupling across catalyst-support interfaces. Electrochemical tests reveal distinctly different oxygen catalytic activities among the hybrids, Mn x Co 3-x O 4 @NCNTs. Nanocrystalline MnCo 2 O 4 @NCNTs (MCO@NCNTs) hybrids show superior ORR activity, with a favorable potential to reach 3 mA cm -2 and a high current density response, equivalent to that of the commercial Pt/C standard. Moreover, the hybrid structure exhibits tunable and durable catalytic activities for both ORR and OER, with a lowest overall potential of 0.93 V. It is clear that the long-term electrochemical activities can be ensured by rational design of hybrid structures from the nanoscale. © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

N/S/B-doped graphitized carbon encased Fe species as a highly active and durable catalyst towards oxygen reduction reaction.

PubMed

Li, Guang-Lan; Cheng, Guang-Chun; Chen, Wen-Wen; Liu, Cai-Di; Yuan, Li-Fang; Yang, Bei-Bei; Hao, Ce

2018-03-15

Exploring cost-effective, high-performance and durable non-precious metal catalysts is of great significance for the acceleration of sluggish oxygen reduction reaction (ORR). Here, we report an intriguing heteroatom-doped graphitized carbon encased Fe species composite by introducing N, S and B sequentially. The experimental approach was designed ingeniously for that the FeCl 3 ·6H 2 O could catalyze thiourea to synthesize N, S co-doped carbon materials which would further react with H 3 BO 3 and NH 3 (emerged at the heat-treatment process) to prepare N, S and B co-doped carbon materials (Fe-N/S/B-C). The Fe-N/S/B-C exhibits an impressive ORR activity for its half-wave potential of -0.1 V, which is 36 mV or 19 mV higher than that of the corresponding single or dual doped counterparts (Fe-N-C or Fe-N/S-C) and 31 mV positive than that of Pt/C catalyst, respectively. Further chronoamperometric measurement and accelerated aging test confirm the excellent electrochemical durability of Fe-N/S/B-C with the stable core-shell structure. The remarkable ORR performance and facile preparation method enable Fe-N/S/B-C as a potential candidate in electrochemical energy devices. Copyright © 2017 Elsevier Inc. All rights reserved.

Controllable deposition of platinum layers on oxide surfaces for the synthesis of fuel cell catalysts

DOE PAGES

Vukmirovic, Miomir B.; Kuttiyiel, Kurian A.; Meng, Hui; ...

2016-09-13

Reducing the amount of Pt, the most costly component of both anode and cathode fuel cell catalysts, has attracted considerable attention from the research community. An approach is reported herein to deposit sub-monolayer to multilayer amounts of Pt and other noble metals on metal oxides and oxidized carbon materials. The process is exemplified by Pt deposition on RuO 2(110). The Pt deposit consists of Pt atoms arranged in a c(2×2) array, that is, a 0.25 monolayer (ML). The deposit has lower catalytic activity for the oxygen reduction reaction (ORR) and similar activity for the hydrogen oxidation reaction compared to Pt(111).more » These activities are explained by a large calculated upshift of the d-band center of Pt atoms and larger Pt–Pt interatomic distances than those of Pt(111). A catalyst with Pt coverage larger than 0.25 ML on oxide surfaces and oxidized carbon materials is shown to be active for the ORR as well as for other electrocatalytic reactions. A PtRhSnO 2/C catalyst shows high activity for ethanol oxidation as a result of its ability to effectively cleave the C–C bond in ethanol. Furthermore, Pt deposited on reduced graphene oxide shows high Pt mass ORR activity and good stability.« less

Self-assembly of cobalt-centered metal organic framework and multiwalled carbon nanotubes hybrids as a highly active and corrosion-resistant bifunctional oxygen catalyst

NASA Astrophysics Data System (ADS)

Fang, Yiyun; Li, Xinzhe; Li, Feng; Lin, Xiaoqing; Tian, Min; Long, Xuefeng; An, Xingcai; Fu, Yan; Jin, Jun; Ma, Jiantai

2016-09-01

Metal organic frameworks (MOF) derived carbonaceous materials have emerged as promising bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts for electrochemical energy conversion and storage. But previous attempts to overcome the poor electrical conductivity of MOFs hybrids involve a harsh high-template pyrolytic process to in situ form carbon, which suffer from extremely complex operation and inevitable carbon corrosion at high positive potentials when OER is operated. Herein, a self-assembly approach is presented to synthesize a non-precious metal-based, high active and strong durable Co-MOF@CNTs bifunctional catalyst for OER and ORR. CNTs not only improve the transportation of the electrons but also can sustain the harsh oxidative environment of OER without carbon corrosion. Meanwhile, the unique 3D hierarchical structure offers a large surface area and stable anchoring sites for active centers and CNTs, which enables the superior durability of hybrid. Moreover, a synergistic catalysis of Co(II), organic ligands and CNTs will enhance the bifunctional electrocatalytic performance. Impressively, the hybrid exhibits comparable OER and ORR catalytic activity to RuO2 and 20 wt% Pt/C catalysts and superior stability. This facile and versatile strategy to fabricating MOF-based hybrids may be extended to other electrode materials for fuel cell and water splitting applications.

Long-term stability of nanostructured thin film electrodes at operating potentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahluwalia, Rajesh K.; Peng, J. -K.; Wang, X.

Long-term stability of nanostructured thin film (NSTF) catalysts at operating potentials has been investigated. Compared to high surface area Pt/C catalysts, NSTF electrodes show 20–50x smaller F – emission rates (FER) because of their high specific activity for oxygen reduction reaction (ORR), but are susceptible to poisoning by the products of membrane degradation because of their low electrochemically active surface area (ECSA). The observed voltage degradation rates at potentials corresponding to 1–1.5 A/cm 2 current density are much higher than the allowable 13–14 μV/h. Although F – is not itself responsible for performance decay, cumulative fluoride release (CFR) is amore » good marker for catalyst surface contamination. The observed performance decay is not only due to loss of active Pt sites but also adsorbed impurities impeding ORR kinetics. There is a strong correlation between measured CFR and observed decrease in specific ORR activity and limiting current density and increase in mass transfer overpotentials. Furthermore, the correlations indicate that the target of <10% lifetime performance degradation can be achieved by restricting CFR in NSTF electrodes to 0.7 μg/cm 2, as may be possible with more stable membranes, higher surface area NSTF catalysts, and cell operation at lower temperatures and higher relative humidities.« less

Ultralow content of Pt on Pd–Co–Cu/C ternary nanoparticles with excellent electrocatalytic activity and durability for the oxygen reduction reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Sufen; Xiao, Weiping; Wang, Jie

Optimizing the utilization of Pt to catalyze the sluggish kinetics of the oxygen reduction reaction (ORR) is of vital importance in proton exchange membrane fuel cells. One of the strategies is to spread Pt atoms over the surface of a substrate to increase the surface area. We report a facile method to synthesize Pd6CoCu@Pt/C core-shell nanoparticles with an ultralow amount of Pt. It was found that Pt-coated layer on Pd6CoCu cores plays a vital role in enhancing the ORR activity and the cycling stability. The half-wave potential of Pd6CoCu@Pt/C positively shifts about 50 mV and 17 mV relative to Pd6CoCu/Cmore » and Pt/C, respectively. The Pt mass activity on Pd6CoCu@Pt/C was calculated to be about 27 times higher than that on Pt/C catalysts at 0.9 V. Furthermore, the Pd6CoCu@Pt/C nanoparticles exhibit superior stability with almost no decay for the ORR polarization curves during 10,000 potential cycles and the core-shell structure remains with only a slight increase in the thickness of the Pt overlayer. Our findings provide a methodology for synthesizing highly efficient catalytic materials for the cathodic application in fuel cells.« less

Correlation between theoretical descriptor and catalytic oxygen reduction activity of graphene supported palladium and palladium alloy electrocatalysts

NASA Astrophysics Data System (ADS)

Seo, Min Ho; Choi, Sung Mook; Lee, Dong Un; Kim, Won Bae; Chen, Zhongwei

2015-12-01

The oxygen reduction reaction, ORR, performances of graphene-supported palladium (Pd) and palladium alloys (Pd3X: X = Ag, Co and Fe) catalysts with highly dispersed catalyst particles are investigated in acidic and alkaline conditions using a rotating disk electrode, RDE. Graphene nanosheet, GNS, supported Pd based catalysts are fabricated without surfactant through the impregnation of Pd and 2nd metal precursors on GNS, leading to small and uniformly dispersed nanoparticles, even when high metal loading of up to 60 wt.% are deposited on supports. The ab-initio density functional theory, DFT, calculations, which are based on the d-band center theory, have been applied to correlate with the results of the ORR performances obtained by half-cell tests. Additionally, the cohesive energy, Ecoh, and dissolution potential, Um, for the Pd nanoparticles have been calculated to understand thermodynamic stability. To elucidate the d-band center shift, the Pd 3d5/2 core-level binding energies for Pd/GNS, Pd3Ag/GNS, Pd3Fe/GNS and Pd3Co/GNS have been investigated by X-ray photoelectron spectroscopy, XPS. The GNS-supported Pd, or Pd-based alloy-nanoparticle catalyst shows good ORR activity under acidic and alkaline conditions, suggesting it may offer potential replacement for Pt for use in cathode electrodes of anion-exchange membrane fuel cell, AEMFC, and acid based polymer electrolyte fuel cell, PEMFC.

Trends in Adsorption Energies of the Oxygenated Species on Single Platinum Atom Embedded in Carbon Nanotubes

DOE PAGES

Siahrostami, Samira; Li, Guo-Ling; Nørskov, Jens K.; ...

2017-09-30

Herein we study the effect of strain on the catalytic activity of different Pt-doped single wall metallic carbon nanotubes (SWCNT) towards the oxygen reduction reaction (ORR). We consider the possibility of the Pt-doped at single vacancy inside the SWCNT to investigate the effect of confinement on the reaction mechanism. Density functional theory calculations indicate that for the SWCNTs with tube diameters below 7 Å, the strain energy varies significantly influencing the adsorption energies of the key intermediates of the ORR reaction. For the SWCNTs with tube diameters above 7 Å, on the other hand, both the calculated strain and themore » adsorption energies are almost constant. We furthermore find that the adsorption energies are strongly affected by confinement effects as shown for Pt-doped systems that are located inside the SWCNT. We show that the Pt-doped at single vacancy of the SWCNT strongly binds the oxygenated species under ORR potentials and therefore the active species is covered by oxo- or hydroxo group. Because the presence of Pt atoms doped at the single and double vacancies of the SWCNT is equivalently probable we also studied the Pt-doped at double vacancy. We find that the most active motif is the Pt-doped at double vacancy of SWCNT with 0.24V overpotenital.« less

Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

NASA Astrophysics Data System (ADS)

Kim, In Gyeom; Nah, In Wook; Oh, In-Hwan; Park, Sehkyu

2017-10-01

Three-dimensional (3D) crumpled reduced graphene oxide supported Pt-Ir alloys that served as bifunctional oxygen catalysts for use in untized regenerative fuel cells were synthesized by a facile spray pyrolysis method. Pt-Ir catalysts supported on rGO (Pt-Ir/rGOs) were physically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) to observe change in composition by heat treatment, alloying, and morphological transition of the catalysts. Their catalytic activities and stabilities for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) conditions were electrochemically investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), potential cycling and hold tests on the rotating disk electrode (RDE). Pt-Ir/rGO with no post heat-treatment (Pt-Ir/rGO_NP) showed a lower activity for ORR and OER although metal nanoparticles decorated on the support are relatively small. However, Pt-Ir/rGO showed remarkably enhanced activity following heat treatment, depending on temperature. Pt-Ir/rGO heat-treated at 600 °C after spray pyrolysis (Pt-Ir/rGO_P600) exhibited a higher activity and stability than a commercially available Pt/C catalyst kept under the ORR condition, and it also revealed a comparable OER activity and durability versus the commercial unsupported Ir catalyst.

Iridium-decorated palladium-platinum core-shell catalysts for oxygen reduction reaction in proton exchange membrane fuel cell.

PubMed

Wang, Chen-Hao; Hsu, Hsin-Cheng; Wang, Kai-Ching

2014-08-01

Carbon-supported Pt, Pd, Pd-Pt core-shell (Pt(shell)-Pd(core)/C) and Ir-decorated Pd-Pt core-shell (Ir-decorated Pt(shell)-Pd(core)/C) catalysts were synthesized, and their physical properties, electrochemical behaviors, oxygen reduction reaction (ORR) characteristics and proton exchange membrane fuel cell (PEMFC) performances were investigated herein. From the XRD patterns and TEM images, Ir-decorated Pt(shell)-Pd(core)/C has been confirmed that Pt was deposited on the Pd nanoparticle which had the core-shell structure. Ir-decorated Pt(shell)-Pd(core)/C has more positive OH reduction peak than Pt/C, which is beneficial to weaken the binding energy of Pt-OH during the ORR. Thus, Ir-decorated Pt(shell)-Pd(core)/C has higher ORR activity than Pt/C. The maximum power density of H2-O2 PEMFC using Ir-decorated Pt(shell)-Pd(core)/C is 792.2 mW cm(-2) at 70°C, which is 24% higher than that using Pt/C. The single-cell accelerated degradation test of PEMFC using Ir-decorated Pt(shell)-Pd(core)/C shows good durability by the potential cycling of 40,000 cycles. This study concludes that Ir-decorated Pt(shell)-Pd(core)/C has the low Pt content, but it can facilitate the low-cost and high-efficient PEMFC. Copyright © 2013 Elsevier Inc. All rights reserved.

Pt skin coated hollow Ag-Pt bimetallic nanoparticles with high catalytic activity for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Fu, Tao; Huang, Jianxing; Lai, Shaobo; Zhang, Size; Fang, Jun; Zhao, Jinbao

2017-10-01

The catalytic activity and stability of electrocatalyst is critical for the commercialization of fuel cells, and recent reports reveal the great potential of the hollow structures with Pt skin coat for developing high-powered electrocatalysts due to their highly efficient utilization of the Pt atoms. Here, we provide a novel strategy to prepare the Pt skin coated hollow Ag-Pt structure (Ag-Pt@Pt) of ∼8 nm size at room temperature. As loaded on the graphene, the Ag-Pt@Pt exhibits a remarkable mass activity of 0.864 A/mgPt (at 0.9 V, vs. reversible hydrogen electrode (RHE)) towards oxygen reduction reaction (ORR), which is 5.30 times of the commercial Pt/C catalyst, and the Ag-Pt@Pt also shows a better stability during the ORR catalytic process. The mechanism of this significant enhancement can be attributed to the higher Pt utilization and the unique Pt on Ag-Pt surface structure, which is confirmed by the density functional theory (DFT) calculations and other characterization methods. In conclusion, this original work offers a low-cost and environment-friendly method to prepare a high active electrocatalyst with cheaper price, and this work also discloses the correlation between surface structures and ORR catalytic activity for the hollow structures with Pt skin coat, which can be instructive for designing novel advanced electrocatalysts for fuel cells.

MIL-100-Fe derived N-doped Fe/Fe3C@C electrocatalysts for efficient oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Guo, Dakai; Han, Sancan; Wang, Jiacheng; Zhu, Yufang

2018-03-01

N-doped porous Fe/Fe3C@C electrocatalysts were prepared by the pyrolysis of the hexamethylenetetramine (HMT)-incorporated MIL-100-Fe at different temperatures (700-1000 °C) under N2 atmosphere. Rotary evaporation of MIL-100-Fe and HMT solution could make more N-enriched HMT molecules enter into the pores of MIL-100-Fe, thus improving nitrogen contents of the final pyrolyzed samples. All pyrolyzed samples show porous textures with middle specific surface areas. The X-ray photoelectron spectroscopy (XPS) results demonstrate the successful introduction of N atoms into carbon framework. Sample Fe-N2-800 prepared by annealing the precursors with the HMT/MIL-100-Fe weight ratio of 2 at 800 °C exhibits the best electrocatalytic activity towards the oxygen reduction reaction (ORR) in terms of onset potential and current density because of high graphitic N and pyridinic N content. The enwrapped Fe/Fe3C nanoparticles and Fe-Nx active sites in these samples could also boost the ORR activity synergistically. Moreover, sample Fe-N2-800 demonstrates a dominant four electron reduction process, as well as excellent long-term operation stability and methanol crossover resistance. Thus, the N-doped Fe/Fe3C@C composites derived from the HMT-incorporated MIL-100-Fe are promising electrocatalysts to replace Pt/C for ORR in practical applications.

Oxygen reduction reaction of (C-PCTNB@CNTs): A nitrogen and phosphorus dual-doped carbon electro-catalyst derived from polyphosphazenes

NASA Astrophysics Data System (ADS)

Dar, Sami Ullah; Ud Din, Muhammad Aizaz; Hameed, Muhammad Usman; Ali, Shafqat; Akram, Raheel; Wu, Zhanpeng; Wu, Dezhen

2018-01-01

This research describes the synthesis of a novel type of poly [cyclotriphosphazene-co-1,3,5-triol nitrobenzene] (PCTNB) microspheres with uniform size and diameter of more than 2 μm having well characterization. These microspheres are further used to wrap the CNTs by a facile route using template based non-covalent method to form PCTNB@CNTs composite. This composite is further well analyzed before it is subjected to pyrolysis. The direct carbonization of the PCTNB@CNTs is performed at 600 °C at a rate of 5 °C/min under N2 atmosphere to render the N, P, O doped carbonized PCTNB@CNTs having enhanced electronic features to be applied as an ORR electrocatalysts in fuel cells accompanied by TEM, XPS, Raman, FT-IR, TGA and BET analyses. Here, we have designed a metal-free, N, P, O doped (C-PCTNB@CNTs) electro-catalyst which exhibit significantly high ORR performance in acidic PEM cells showing much higher onset potential of (0.94 V) and half-wave potential of (0.85 V) with electron transfer number (n) 3.9 at 0.4-0.7 V as compared to other non-metallic electro-catalysts. Thus, (C-PCTNB@CNTs) is a metal-free, methanol tolerant carbon-based ORR catalyst, and it opens up new avenues for clean energy generation for affordable and durable fuel cells.

Ultralow content of Pt on Pd–Co–Cu/C ternary nanoparticles with excellent electrocatalytic activity and durability for the oxygen reduction reaction

DOE PAGES

Liu, Sufen; Xiao, Weiping; Wang, Jie; ...

2016-08-01

Optimizing the utilization of Pt to catalyze the sluggish kinetics of the oxygen reduction reaction (ORR) is of vital importance in proton exchange membrane fuel cells. One of the strategies is to spread Pt atoms over the surface of a substrate to increase the surface area. We report a facile method to synthesize Pd6CoCu@Pt/C core-shell nanoparticles with an ultralow amount of Pt. It was found that Pt-coated layer on Pd6CoCu cores plays a vital role in enhancing the ORR activity and the cycling stability. The half-wave potential of Pd6CoCu@Pt/C positively shifts about 50 mV and 17 mV relative to Pd6CoCu/Cmore » and Pt/C, respectively. The Pt mass activity on Pd6CoCu@Pt/C was calculated to be about 27 times higher than that on Pt/C catalysts at 0.9 V. Furthermore, the Pd6CoCu@Pt/C nanoparticles exhibit superior stability with almost no decay for the ORR polarization curves during 10,000 potential cycles and the core-shell structure remains with only a slight increase in the thickness of the Pt overlayer. Our findings provide a methodology for synthesizing highly efficient catalytic materials for the cathodic application in fuel cells.« less

Long-term stability of nanostructured thin film electrodes at operating potentials

DOE PAGES

Ahluwalia, Rajesh K.; Peng, J. -K.; Wang, X.; ...

2017-02-09

Long-term stability of nanostructured thin film (NSTF) catalysts at operating potentials has been investigated. Compared to high surface area Pt/C catalysts, NSTF electrodes show 20–50x smaller F – emission rates (FER) because of their high specific activity for oxygen reduction reaction (ORR), but are susceptible to poisoning by the products of membrane degradation because of their low electrochemically active surface area (ECSA). The observed voltage degradation rates at potentials corresponding to 1–1.5 A/cm 2 current density are much higher than the allowable 13–14 μV/h. Although F – is not itself responsible for performance decay, cumulative fluoride release (CFR) is amore » good marker for catalyst surface contamination. The observed performance decay is not only due to loss of active Pt sites but also adsorbed impurities impeding ORR kinetics. There is a strong correlation between measured CFR and observed decrease in specific ORR activity and limiting current density and increase in mass transfer overpotentials. Furthermore, the correlations indicate that the target of <10% lifetime performance degradation can be achieved by restricting CFR in NSTF electrodes to 0.7 μg/cm 2, as may be possible with more stable membranes, higher surface area NSTF catalysts, and cell operation at lower temperatures and higher relative humidities.« less

Cobalt Nanoparticle-Embedded Porous Carbon Nanofibers with Inherent N- and F-Doping as Binder-Free Bifunctional Catalysts for Oxygen Reduction and Evolution Reactions.

PubMed

Singhal, Richa; Kalra, Vibha

2017-01-18

Efficient, low-cost, non-precious metal-based, and stable bifunctional electrocatalysts are key to various energy storage and conversion devices such as regenerative fuel cells and metal-air batteries. In this work, we report cobalt nanoparticle-embedded porous carbon nanofibers with inherent N- and F-doping as binder-free bifunctional electrocatalysts with excellent activity for both the oxygen reduction and oxygen evolution reaction (ORR/OER) in an alkaline medium. Single-step electrospinning of a solution of the polymer mixture (carbon precursor) and the cobalt precursor followed by controlled pyrolysis with an intermediate reduction step in H 2 (to reduce cobalt oxides to cobalt) was utilized to synthesize an integrated freestanding catalyst. The fabricated catalyst with effective structural and electronic interaction between the cobalt metal nanoparticles and the N- and F-doped carbon defect sites showed enhanced catalytic properties compared to the benchmark catalysts for ORR and OER (Pt, Ir, and Ru). The ORR potential at the current density of -3 mA cm -2 was 0.81 V RHE and the OER potential at a current density of 10 mA cm -2 was 1.595 V RHE , resulting in a ΔE of only 0.785 V. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc–Air Battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hui; Li, Qi; Wen, Peng

Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this paper, highly monodisperse CoP and Co 2P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co 2P NCs show higher OER performance owing to easier formation of plentiful Co 2P@COOH heterojunctions. Density functional theory calculation results indicate that themore » desorption of OH* from cobalt sites is the rate-limiting step for both CoP and Co 2P in ORR and that the high content of phosphide can lower the reaction barrier. A water electrolyzer constructed with a CoP NC cathode and a Co 2P NC anode can achieve a current density of 10 mA cm -2 at 1.56 V, comparable even to the noble metal-based Pt/C and RuO 2/C pair. Finally and furthermore, the CoP NCs are employed as an air cathode in a primary zinc–air battery, exhibiting a high power density of 62 mW cm -2 and good stability.« less

A Robust Hybrid Zn-Battery with Ultralong Cycle Life.

PubMed

Li, Bing; Quan, Junye; Loh, Adeline; Chai, Jianwei; Chen, Ye; Tan, Chaoliang; Ge, Xiaoming; Hor, T S Andy; Liu, Zhaolin; Zhang, Hua; Zong, Yun

2017-01-11

Advanced batteries with long cycle life and capable of harnessing more energies from multiple electrochemical reactions are both fundamentally interesting and practically attractive. Herein, we report a robust hybrid zinc-battery that makes use of transition-metal-based redox reaction (M-O-OH → M-O, M = Ni and Co) and oxygen reduction reaction (ORR) to deliver more electrochemical energies of comparably higher voltage with much longer cycle life. The hybrid battery was constructed using an integrated electrode of NiCo 2 O 4 nanowire arrays grown on carbon-coated nickel foam, coupled with a zinc plate anode in alkaline electrolyte. Benefitted from the M-O/M-O-OH redox reactions and rich ORR active sites in NiCo 2 O 4 , the battery has concurrently exhibited high working voltage (by M-O-OH → M-O) and high energy density (by ORR). The good oxygen evolution reaction (OER) activity of the electrode and the reversible M-O ↔ M-O-OH reactions also enabled smooth recharging of the batteries, leading to excellent cycling stabilities. Impressively, the hybrid batteries maintained highly stable charge-discharge voltage profile under various testing conditions, for example, almost no change was observed over 5000 cycles at a current density of 5 mA cm -2 after some initial stabilization. With merits of higher working voltage, high energy density, and ultralong cycle life, such hybrid batteries promise high potential for practical applications.

Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc–Air Battery

DOE PAGES

Li, Hui; Li, Qi; Wen, Peng; ...

2018-01-15

Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this paper, highly monodisperse CoP and Co 2P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co 2P NCs show higher OER performance owing to easier formation of plentiful Co 2P@COOH heterojunctions. Density functional theory calculation results indicate that themore » desorption of OH* from cobalt sites is the rate-limiting step for both CoP and Co 2P in ORR and that the high content of phosphide can lower the reaction barrier. A water electrolyzer constructed with a CoP NC cathode and a Co 2P NC anode can achieve a current density of 10 mA cm -2 at 1.56 V, comparable even to the noble metal-based Pt/C and RuO 2/C pair. Finally and furthermore, the CoP NCs are employed as an air cathode in a primary zinc–air battery, exhibiting a high power density of 62 mW cm -2 and good stability.« less

Reduced graphene oxide supported MnS nanotubes hybrid as a novel non-precious metal electrocatalyst for oxygen reduction reaction with high performance

NASA Astrophysics Data System (ADS)

Tang, Yongfu; Chen, Teng; Guo, Wenfeng; Chen, Shunji; Li, Yanshuai; Song, Jianzheng; Chang, Limin; Mu, Shichun; Zhao, Yufeng; Gao, Faming

2017-09-01

Electronic structure of Mn cations, electric conductivity of active materials and three dimensional structure for mass transport play vital roles in the electrocatalytic activity of Mn-based electrocatalysts for oxygen reduction reaction (ORR). To construct efficient and robust Mn-based electrocatalysts, MnS nanotubes anchored on reduced graphene oxide (MnS-NT@rGO) hybrid was synthesized and used as a novel non-precious metal electrocatalyst for ORR. The formation of nano-tubular structure, which offers more active sites and suitable channels for mass transport to enhance the electrocatalytic activity towards ORR, are carefully illustrated based on the core-dissolution/shell-recrystallization type Ostwald ripening effect. Tuned electronic structure of Mn cations, enhanced electric conductivity and suitable nano-tubular structure endow MnS-NT@rGO electrocatalyst comparative catalytic activity to commercial 20 wt % Pt/C in alkaline electrolyte. The MnS-NT@rGO electrocatalyst exhibits higher catalytic activity than rGO supported MnS nanoparticles (MnS-NP@rGO) and MnS nanotubes without rGO substrate (MnS-NT), as well as rGO supported Mn(OH)2 (Mn(OH)2@rGO) and rGO supported MnO (MnO@rGO). Moreover, the MnS-NT@rGO electrocatalyst shows superior durability and methanol tolerance to commercial Pt/C.

Rationalization of Au concentration and distribution in AuNi@Pt core-shell nanoparticles for oxygen reduction reaction

DOE PAGES

An, Wei; Liu, Ping

2015-09-18

Improving the activity and stability of Pt-based core–shell nanocatalysts for proton exchange membrane fuel cells while lowering Pt loading has been one of the big challenges in electrocatalysis. Here, using density functional theory, we report the effect of adding Au as the third element to enhance the durability and activity of Ni@Pt core–shell nanoparticles (NPs) during the oxygen reduction reaction (ORR). Our results show that the durability and activity of a Ni@Pt NP can be finely tuned by controlling Au concentration and distribution. For a NiAu@Pt NP, the durability can be greatly promoted by thermodynamically favorable segregation of Au tomore » replace the Pt atoms at vertex, edge, and (100) facets on the shell, while still keeping the ORR activity on the active Pt(111) shell as high as that of Ni@Pt nanoparticles. Such behavior strongly depends on a direct interaction with the Ni interlayer. The results not only highlight the importance of interplay between surface strain on the shell and the interlayer–shell interaction in determining the durability and activity but also provide guidance on how to maximize the usage of Au to optimize the performance of core–shell (Pt) nanoparticles. As a result, such understanding has allowed us to discover a novel NiAu@Pt nanocatalyst for the ORR.« less

Overweight is associated to a better prognosis in metastatic colorectal cancer: A pooled analysis of FFCD trials.

PubMed

Aparicio, Thomas; Ducreux, Michel; Faroux, Roger; Barbier, Emilie; Manfredi, Sylvain; Lecomte, Thierry; Etienne, Pierre-Luc; Bedenne, Laurent; Bennouna, Jaafar; Phelip, Jean-Marc; François, Eric; Michel, Pierre; Legoux, Jean-Louis; Gasmi, Mohamed; Breysacher, Gilles; Rougier, Philippe; De Gramont, Aimery; Lepage, Come; Bouché, Olivier; Seitz, Jean-François

2018-07-01

Previous studies showed that high and low body mass index (BMI) was associated with worse prognosis in early-stage colorectal cancer (CRC), and low BMI was associated with worse prognosis in metastatic CRC (mCRC). We aimed to assess efficacy outcomes according to BMI. A pooled analysis of individual data from 2085 patients enrolled in eight FFCD first-line mCRC trials from 1991 to 2013 was performed. Comparisons were made according to the BMI cut-off: Obese (BMI ≥30), overweight patients (BMI ≥ 25), normal BMI patients (BMI: 18.5-24) and thin patients (BMI <18.5). Interaction tests were performed between BMI effect and sex, age and the addition of antiangiogenics to chemotherapy. The rate of BMI ≥25 patients was 41.5%, ranging from 37.6% (1991-1999 period) to 41.5% (2000-2006 period) and 44.8% (2007-2013 period). Comparison of overweight patients versus normal BMI range patients revealed a significant improvement of median overall survival (OS) (18.5 versus 16.3 months, HR = 0.88 [0.80-0.98] p = 0.02) and objective response rate (ORR) (42% versus 36% OR = 1.23 [1.01-1.50] p = 0.04) but a comparable median progression-free survival (PFS) (7.8 versus 7.2 months, HR = 0.96 [0.87-1.05] p = 0.35). Subgroup analyses revealed that overweight was significantly associated with better OS in men. OS and PFS were significantly shorter in thin patients. Overweight patients had a prolonged OS compared with normal weight patients with mCRC. The association of overweight with better OS was only observed in men. The pejorative prognosis of BMI <18.5 was confirmed. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Synthesis and x-ray characterization of cobalt phosphide (Co₂P) nanorods for the oxygen reduction reaction

DOE PAGES

Doan-Nguyen, Vicky V.T.; Su, Dong; Zhang, Sen; ...

2015-07-14

Low temperature fuel cells are clean, effective alternative fuel conversion technology. Oxygen reduction reaction (ORR) at the fuel cell cathode has required Pt as the electrocatalyst for high activity and selectivity of the four-electron reaction pathway. Targeting a less expensive, earth abundant alternative, we have developed the synthesis of cobalt phosphide (Co₂P) nanorods for ORR. Characterization techniques that include total X-ray scattering and extended X-ray absorption fine structure revealed a deviation of the nanorods from bulk crystal structure with a contraction along the b orthorhombic lattice parameter. The carbon supported nanorods have comparable activity but are remarkably more stable thanmore » conventional Pt catalysts for the oxygen reduction reaction in alkaline environments.« less

A bio-inspired N-doped porous carbon electrocatalyst with hierarchical superstructure for efficient oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Miao, Yue-E.; Yan, Jiajie; Ouyang, Yue; Lu, Hengyi; Lai, Feili; Wu, Yue; Liu, Tianxi

2018-06-01

The bio-inspired hierarchical "grape cluster" superstructure provides an effective integration of one-dimensional carbon nanofibers (CNF) with isolated carbonaceous nanoparticles into three-dimensional (3D) conductive frameworks for efficient electron and mass transfer. Herein, a 3D N-doped porous carbon electrocatalyst consisting of carbon nanofibers with grape-like N-doped hollow carbon particles (CNF@NC) has been prepared through a simple electrospinning strategy combined with in-situ growth and carbonization processes. Such a bio-inspired hierarchically organized conductive network largely facilitates both the mass diffusion and electron transfer during the oxygen reduction reactions (ORR). Therefore, the metal-free CNF@NC catalyst demonstrates superior catalytic activity with an absolute four-electron transfer mechanism, strong methanol tolerance and good long-term stability towards ORR in alkaline media.