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1.
Acute Med Surg ; 11(1): e946, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38584667

RESUMO

Background: Penetrating thoracic trauma with coronary artery transection is a lethal injury, but is rare. We report a case of a cardiac stab wound with coronary artery transection that was successfully treated after preoperative diagnosis. Case Presentation: A 36-year-old man was transferred to our emergency department with a left chest stab wound. A coronary computed tomography-angiography scan, including coronary angiography, revealed left hemopneumothorax and left anterior descending branch transection, with ischemic changes in the left ventricular myocardium. Given the diagnosis of coronary artery transection and the absence of injury to the surrounding arteries, we were able to perform coronary artery bypass surgery using the left internal thoracic artery. The patient's postoperative course was good, and he was discharged on foot without major complications 18 days after surgery. Conclusion: Unless a resuscitative thoracotomy is required, a preoperative computed tomography scan, including coronary angiography, may be useful for accurate preoperative diagnosis for patients at high risk of myocardial or coronary artery injury.

2.
RSC Adv ; 13(20): 13472-13476, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37143913

RESUMO

Production of aromatic compounds from lignocellulosic biomass has recently been one goal of efforts to establish a sustainable society. We studied cellulose conversion into aromatic compounds over charcoal-supported metal catalysts (Pt/C, Pd/C, Rh/C, and Ru/C) in water at temperatures of 473-673 K. We found that charcoal-supported metal catalysts enhanced conversion of cellulose to aromatic compounds such as benzene, toluene, phenol, and cresol. The total yields of aromatic compounds produced from cellulose decreased in the order: Pt/C > Pd/C > Rh/C > no catalyst > Ru/C. This conversion could proceed even at 523 K. The total yield of aromatic compounds reached 5.8% with Pt/C at 673 K. The charcoal-supported metal catalysts also enhanced conversion of hemicellulose to aromatic compounds.

3.
ChemistryOpen ; 10(3): 307, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33590696

RESUMO

Invited for this month's cover are the groups of Prasert Reubroycharoen at the Chulalongkorn University (Thailand) and Aritomo Yamaguchi at the National Institute of Advanced Industrial Science and Technology (Japan). The cover picture shows the the conversion of chitin, which is generated by food processing, into lactic acid with catalysis by magnesium oxides. Although chitin, a main component of the shells of crustaceans, can be converted to valuable products by means of homogeneous catalysis, most of the chitin is treated as industrial waste because use of homogeneous catalysts is compromised by difficulties associated with product separation from the catalysts and the recyclability of the catalysts. Thus, a method for converting chitin to useful chemicals, such as lactic acid, by using solid catalysts would be beneficial. Magnesium oxide catalysts can be reused twice without loss of activity. Read the full text of their Full Paper at 10.1002/open.202000303.

4.
ChemistryOpen ; 10(3): 308-315, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33492785

RESUMO

Although chitin, an N-acetyl-D-glucosamine polysaccharide, can be converted to valuable products by means of homogeneous catalysis, most of the chitin generated by food processing is treated as industrial waste. Thus, a method for converting this abundant source of biomass to useful chemicals, such as lactic acid, would be beneficial. In this study, we determined the catalytic activities of various metal oxides for chitin conversion at 533 K and found that MgO showed the highest activity for lactic acid production. X-ray diffraction analysis and thermogravimetry-differential thermal analysis showed that the MgO was transformed to Mg(OH)2 during chitin conversion. The highest yield of lactic acid (10.8 %) was obtained when the reaction was carried out for 6 h with 0.5 g of the MgO catalyst. The catalyst could be recovered as a solid residue after the reaction and reused twice with no decrease in the lactic acid yield.


Assuntos
Quitina/química , Ácido Láctico/síntese química , Óxido de Magnésio/química , Catálise , Reutilização de Equipamento , Modelos Químicos
5.
Carbohydr Res ; 487: 107880, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31785566

RESUMO

Intramolecular dehydration of the biomass-derived hexitols D-sorbitol, D-mannitol, and galactitol was investigated. These reactions were performed in high-temperature water at 523-573 K without added acid catalyst. The rate constants for the dehydration steps in the reaction networks were determined at various reaction temperatures, and the activation energies and pre-exponential factors were calculated from Arrhenius plots. The yield of each product was estimated as a function of reaction time and temperature using the calculated rate constants and activation energies. The maximum yield of each product from the dehydration reactions was predicted over a range of reaction time and temperature, allowing the selective production of these important platform chemicals.


Assuntos
Álcoois Açúcares/química , Temperatura , Água/química , Desidratação , Cinética , Estrutura Molecular
6.
Gan To Kagaku Ryoho ; 45(4): 731-733, 2018 Apr.
Artigo em Japonês | MEDLINE | ID: mdl-29650850

RESUMO

INTRODUCTION: The indication of hepatectomy for liver metastasis from gastric cancer has not been definitely established. PATIENTS AND METHODS: Among 12 cases that were performed hepatectomy for liver metastasis from gastric cancer in our institute from 2008 to 2016, we analysed prognosis and the benefit of surgical resection. RESULTS: The overall 5-year survival rates of all cases were 42.3%, and median survival time was 2 years. The overall survival rates of synchronous metastasis was 59.3%and of metachronous metastasis was 0%. Recurrence rate of all cases within 1 year was 75%. There was no long-term survivor for metachronous metastasis because of its early recurrence though it was solitary liver tumor. CONCLUSION: We should carefully indicate surgical resection for liver metastasis from gastric cancer.


Assuntos
Neoplasias Hepáticas/secundário , Neoplasias Gástricas/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Gastrectomia , Hepatectomia , Humanos , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico
7.
ACS Chem Biol ; 13(5): 1313-1321, 2018 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-29620349

RESUMO

In Arabidopsis, signaling of the stress hormone abscisic acid (ABA) is mediated by PYR/PYL/RCAR receptors (PYLs), which bind to and inhibit group-A protein phosphatases 2C (PP2Cs), the negative regulators of ABA. X-ray structures of several PYL-ABA and PYL-ABA-PP2C complexes have revealed that a conserved tryptophan in PP2Cs is inserted into a small tunnel adjacent to the C4' of ABA in the PYL-ABA complex and plays a crucial role in the formation and stabilization of the PYL-ABA-PP2C complex. Here, 4'-modified ABA analogues were designed to prevent the insertion of the tryptophan into the tunnel adjacent to the C4' of ABA in these complexes. These analogues were predicted to block PYL-PP2C receptor interactions and thus block ABA signaling. To test this, 4'- O-phenylpropynyl ABA analogues were synthesized as novel PYL antagonists (PANs). Structural, thermodynamic, biochemical, and physiological studies demonstrated that PANs completely abolished ABA-induced PYL-PP2C interactions in vitro and suppressed stress-induced ABA responses in vivo more strongly than did 3'-hexylsulfanyl-ABA (AS6), a PYL antagonist we developed previously. The PANs and AS6 antagonized the effects of ABA to different degrees in different plants, suggesting that these PANs can function as chemical scalpels to dissect the complicated regulatory mechanism of ABA signaling in plants.


Assuntos
Ácido Abscísico/antagonistas & inibidores , Proteínas de Arabidopsis/metabolismo , Desenho de Fármacos , Fosfoproteínas Fosfatases/metabolismo , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Estrutura Molecular
8.
ACS Omega ; 3(10): 13862-13868, 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31458084

RESUMO

Here, we report the development of catalysts comprising highly dispersed Au on an alumina (Al2O3) support for the oxidation of glycerol to high-value carboxylic acids in a liquid-phase flow reactor. The catalysts were prepared by means of a deposition-precipitation method. To ensure that the catalysts could be used for long-term catalytic conversions in a liquid-phase flow reactor, we chose an alumina support with high temperature stability and a particle size (50-200 µm) large enough to prevent leakage of the catalyst from the reactor. One of the five catalysts had a high catalytic activity for the conversion of glycerol to the high-value carboxylic acids, glyceric acid and tartronic acid (conversion of glycerol >70%), and the catalyst retained its catalytic activity over long-term use (up to 1770 min). Pretreatment of the catalyst with fructose, a mild reductant, increased the activity of the catalyst. Scanning transmission electron microscopy revealed three Au species highly dispersed on the surface of the alumina support-Au nanoparticles (mode = 7.5-10 nm), Au clusters (1-2 nm), and atomic Au.

9.
Sci Rep ; 7: 46172, 2017 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-28387304

RESUMO

More efficient use of lignin carbon is necessary for carbon-efficient utilization of lignocellulosic biomass. Conversion of lignin into valuable aromatic compounds requires the cleavage of C-O ether bonds and C-C bonds between lignin monomer units. The catalytic cleavage of C-O bonds is still challenging, and cleavage of C-C bonds is even more difficult. Here, we report cleavage of the aromatic C-O bonds in lignin model compounds using supported metal catalysts in supercritical water without adding hydrogen gas and without causing hydrogenation of the aromatic rings. The cleavage of the C-C bond in bibenzyl was also achieved with Rh/C as a catalyst. Use of this technique may greatly facilitate the conversion of lignin into valuable aromatic compounds.

10.
Phys Chem Chem Phys ; 19(4): 2714-2722, 2017 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-27896339

RESUMO

The intramolecular dehydration of biomass-derived sugar alcohols d-sorbitol, d-mannitol, galactitol, xylitol, ribitol, l-arabitol, erythritol, l-threitol, and dl-threitol was investigated in high-temperature water at 523-573 K without the addition of any acid catalysts. d-Sorbitol and d-mannitol were dehydrated into isosorbide and isomannide, respectively, as dianhydrohexitol products. Galactitol was dehydrated into anhydrogalactitols; however, the anhydrogalactitols could not be dehydrated into dianhydrogalactitol products because of the orientation of the hydroxyl groups at the C-3 and C-6 positions. Pentitols such as xylitol, ribitol, and l-arabitol were dehydrated into anhydropentitols. The dehydration rates of the pentitols containing hydroxyl groups in the trans form, which remained as hydroxyl groups in the product tetrahydrofuran, were larger than those containing hydroxyl groups in the cis form because of the structural hindrance caused by the hydroxyl groups in the cis form during the dehydration process. In the case of the tetritols, the dehydration of erythritol was slower than that of threitol, which could also be explained by the structural hindrance of the hydroxyl groups. The dehydration of l-threitol was faster than that of dl-threitol, which implies that molecular clusters were formed by hydrogen bonding between the sugar alcohols in water, which could be an important factor that affects the dehydration process.


Assuntos
Biomassa , Temperatura Alta , Álcoois Açúcares/química , Água/química , Desidratação , Álcoois Açúcares/metabolismo
11.
Gan To Kagaku Ryoho ; 43(12): 1430-1431, 2016 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-28133013

RESUMO

INTRODUCTION: The risk of perforation following endoscopic resection is high. We analyzed the outcome of partial duodenectomy and discussed the therapeutic strategy for duodenal mucosal tumor(DMT). PATIENTS AND METHODS: We analyzed 19 cases who have undergone endoscopic resection, and 11 cases who have undergone partial duodenectomy for DMT in our institute since 2007. We divided them into the first period(ESD actively indicated)and late period(ESD carefully indicated according to the alteration of indication of ESD for DMT in 2013)groups. RESULTS: In the first period, all 17 cases initially underwent endoscopic resection and 4 cases were complicated by perforation. On the other hand, in the late period, 6 of 12 cases initially underwent endoscopic resection and 1 case was complicated by perforation. Emergent partial duodenectomy was performed with additional resection in the perforation cases. There were no complications associated with surgery, and all 29 cases achieved curative resection, based on the histology results. CONCLUSION: We can safely indicate endoscopic resection for DMT with surgical back-up and cooperation with the endoscopic internal department.


Assuntos
Neoplasias Duodenais/cirurgia , Duodenoscopia , Mucosa Intestinal , Humanos , Mucosa Intestinal/patologia , Mucosa Intestinal/cirurgia
12.
Gan To Kagaku Ryoho ; 43(12): 2205-2207, 2016 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-28133270

RESUMO

The patient was a 49-year-old woman with advanced gastric cancer.CT and PET-CT revealed para-aortic lymph node metastases.She was diagnosed with Stage IV T4aN3M1(LYM)and underwent neoadjuvant chemotherapy with S-1 plus CDDP.After 3 courses, both the tumor and para-aortic lymph node metastases decreased in size.Because radical resection was considered possible, she underwent distal gastrectomy with D3(D2+No.1 6a2-b1)dissection and Roux-en-Y reconstruction. Histopathological findings revealed the cancer was Stage I B(yp T1b N1)with the disappearance of cancer cells in the para-aortic lymph nodes.She was discharged on POD 32.She underwent adjuvant chemotherapy with S-1 and was followed up for 3 years with no recurrence.Para -aortic lymph node metastases are factors predicting a poor outcome; however, when neoadjuvant chemotherapy is effective, long-term survival can be expected from gastrectomy with curative PAND.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Terapia Neoadjuvante , Neoplasias Gástricas/tratamento farmacológico , Aorta/patologia , Aorta/cirurgia , Cisplatino/administração & dosagem , Combinação de Medicamentos , Feminino , Humanos , Excisão de Linfonodo , Linfonodos/patologia , Linfonodos/cirurgia , Metástase Linfática , Pessoa de Meia-Idade , Ácido Oxônico/administração & dosagem , Neoplasias Gástricas/irrigação sanguínea , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Tegafur/administração & dosagem
13.
Gan To Kagaku Ryoho ; 43(12): 2301-2303, 2016 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-28133302

RESUMO

We report 2 cases of locally recurrent rectal cancer after intersphincteric resection(ISR)that were controlled with a combination of chemoradiotherapy and abdominoperineal resection(APR). In Case 1, we performed preoperative chemoradiotherapy( TS-1 plus RT 45 Gy)and APR for the local recurrence of ISR. On pathology, viable neoplastic cells were noted. In Case 2, we performed preoperative chemotherapy(Bmab plus mFOLFOX6)and APR for the local recurrence of ISR. On pathology, no viable neoplastic cells were noted. However, a local recurrence developed again 3 months later. Therefore, we performed chemoradiotherapy(TS-1 plus RT 53 Gy). The 2 patients survived without recurrence until now. Their pathology tissues and clinical courses showed that control of local recurrence with only chemoradiotherapy or surgical resection was likely to be difficult. We might be able to improve the prognosis of patients with a combination of chemoradiotherapy and surgical resection.


Assuntos
Quimiorradioterapia , Neoplasias Peritoneais/terapia , Neoplasias Retais/terapia , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Peritoneais/secundário , Neoplasias Retais/patologia , Recidiva , Resultado do Tratamento
14.
Gan To Kagaku Ryoho ; 43(12): 2089-2091, 2016 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-28133231

RESUMO

We report a 5-year surviving patient with unresectable gall bladder carcinoma treated with gemcitabine(GEM)-based chemotherapy. A 64-year-old man was diagnosed with unresectable gall bladder carcinoma with peritoneal dissemination based on laparotomy findings. Two months later, he started to receive GEM chemotherapy. Twelve months after surgery, the patient chose to suspend GEM treatment. One year and 10 months later, multiple lung metastases appeared and GEM was restarted in combination with UFT. Although the primary lesion and lung metastases gradually progressed, the patient maintained a good quality of life. After 3 years and 2 months, chemotherapy was changed to GEM plus S-1 because of progressive disease. Five years and 2 months after surgery, his condition was complicated by a secondary pneumothorax, and the patient received home oxygen therapy. Five years and 8 months after surgery he died of respiratory distress caused by the progression of lung metastases. Even in the case of unresectable advanced gall bladder carcinoma, effective chemotherapy could improve quality of life and prolong survival.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Vesícula Biliar/tratamento farmacológico , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Evolução Fatal , Neoplasias da Vesícula Biliar/patologia , Neoplasias da Vesícula Biliar/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Fatores de Tempo , Gencitabina
15.
Gan To Kagaku Ryoho ; 43(12): 2154-2156, 2016 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-28133253

RESUMO

Multidisciplinary therapy is necessary to prevent recurrence of advanced rectal cancer and advanced cancer with metastases. Here we report a case of long-term survival of a patient with advanced rectal cancer with multiple liver metastases. An 80's woman had previously undergone both Hartmann's operation and a partial hepatectomy for advanced rectal cancer with multiple liver metastases. A year after chemotherapy, a CT scan revealed multiple liver metastases. Thus, we performed partial liver resection. After another round of chemotherapy, a CT scan revealed lung metastases and local recurrence of the rectal cancer; therefore, we performed partial lung resection and a Miles operation. These procedures were conducted 4 years after her first operation. The following year, PET-CT revealed a mediastinum lymph node metastasis; consequently, we performed radiation therapy. New lung metastases and local recurrences of rectal cancer were identified after the radiation therapy; thus, we resumed the therapy, including a molecular targeting drug. Although the patient is in a tumor-bearing state, she is still alive 10 years after her first operation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Retais/tratamento farmacológico , Idoso de 80 Anos ou mais , Colectomia , Terapia Combinada , Feminino , Hepatectomia , Humanos , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/cirurgia , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Recidiva
16.
Gan To Kagaku Ryoho ; 41(12): 2089-91, 2014 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-25731432

RESUMO

A 72-year-old woman was diagnosed with liver dysfunction during a medical examination. An abdominal computed tomography (CT) scan showed multiple nodules in the left lobe, anterior segment, andposterior segment of the liver, leading to a diagnosis of intrahepatic cholangiocarcinoma (ICC). Extended left lobectomy and partial hepatectomy in the anterior and posterior segment with lymph node dissection was performed. At the time of the operation, small nodules on the peritoneum near the stomach were resected; these nodules were diagnosed as peritoneal disseminations of ICC. The histopathological diagnosis was moderately differentiated tubular adenocarcinoma (T4N0M1, Stage IVB). Adjuvant chemotherapy with S-1 was administered for 18 months. Thirty months after the operation, multiple lung metastases were detected by using CT, and chemotherapy with gemcitabine was initiated. Thirty-six months after chemotherapy with gemcitabine, the patient is alive and at home despite her lung metastases, which grew slightly in size. Herein, we report a long-term survival case of ICC with peritoneal dissemination that was successfully treated with surgical resection and adjuvant chemotherapy.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Neoplasias dos Ductos Biliares/tratamento farmacológico , Ductos Biliares Intra-Hepáticos/patologia , Colangiocarcinoma/tratamento farmacológico , Desoxicitidina/análogos & derivados , Ácido Oxônico/uso terapêutico , Neoplasias Peritoneais/tratamento farmacológico , Tegafur/uso terapêutico , Idoso , Neoplasias dos Ductos Biliares/patologia , Neoplasias dos Ductos Biliares/cirurgia , Ductos Biliares Intra-Hepáticos/cirurgia , Quimioterapia Adjuvante , Colangiocarcinoma/patologia , Colangiocarcinoma/cirurgia , Desoxicitidina/uso terapêutico , Combinação de Medicamentos , Feminino , Hepatectomia , Humanos , Excisão de Linfonodo , Neoplasias Peritoneais/secundário , Gencitabina
17.
Gan To Kagaku Ryoho ; 41(12): 2098-100, 2014 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-25731435

RESUMO

We report 3 cases of recurrent hepatic cancer in patients who underwent laparoscopic repeat hepatectomy (LRH). Case 1: A 70-year-old female with ascending colon cancer and liver metastases underwent open right colectomy followed by open S5 resection. Seven months later, the patient experienced a recurrence in the lateral segment and underwent laparoscopy-assisted ( L-A) partial resection. The adhesiolysis around the left liver was performed through a 7-cm upper median incision. Partial resection of the lateral segment was performed by hand-assisted laparoscopic surgery (HALS) using a median incision. Case 2: A 63-year-old female with metachronous liver metastases from rectal cancer underwent open S4a and S5 resection. Nineteen months later, she experienced a recurrence in S4b and underwent an L-A S4b resection. Adhesiolysis around the previous hepatic transection was performed through a small upper median incision. Mobilization of the liver was performed by HALS. A hepatic transection of S4b was also performed in the upper median incision. Case 3: An 80-year-old female with hepatocellular carcinoma (HCC) recurrence in the lateral segment after open S4 resection underwent L-A lateral segmentectomy. An adhesiolysis, mobilization of the liver, and a hepatic transection were performed by HALS and hybrid technique as described in case 2. In a patient with a history of open hepatectomy, LRH may be extensively indicated by utilizing HALS or a hybrid procedure.


Assuntos
Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/cirurgia , Idoso , Idoso de 80 Anos ou mais , Colectomia , Neoplasias do Colo/patologia , Neoplasias do Colo/cirurgia , Feminino , Hepatectomia/métodos , Humanos , Laparoscopia , Pessoa de Meia-Idade , Recidiva
18.
J Phys Chem B ; 110(46): 22995-9, 2006 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-17107135

RESUMO

In recent years, there have been great experimental and theoretical advances in the understanding of the epoxidation of propylene by O(2) and H(2) over Au supported on titanium-containing oxidic supports; however, thus far spectroscopic evidence of reacting species for proposed mechanisms has been lacking. Hydroperoxide species have been postulated as an intermediate responsible for the epoxidation of propylene with O(2) and H(2). In order to obtain direct evidence for the different type of active oxygen species, in situ UV-vis and EPR measurements were carried out during the epoxidation of propylene with O(2) and H(2) over a Au/Ti-SiO(2) (Ti/Si = 3:100) catalyst. It was determined that the adsorbed species of oxygen (O(2)(-)) resided on Au, more likely at a perimeter site, and it led to the formation of titanium hydroperoxo species. These results support the possible mechanism of formation of these hydroperoxo species via H(2)O(2) produced from O(2) and H(2) adsorbed on the Au surfaces.

19.
J Phys Chem B ; 110(43): 21764-70, 2006 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-17064137

RESUMO

Highly active catalysts for oxidative dehydrogenation of ethane with CO2 were characterized by temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), Fourier transform infrared (FTIR) spectroscopy, and X-ray absorption fine-structure (XAFS) analysis. In the active catalysts, Cr/H-ZSM-5 (SiO2/Al2O3 > 190), Cr6+ = O, or possibly Cr5+ = O was the catalytic species on the zeolite support. In contrast, little Cr6+ (or Cr5+) was detected in the less-active catalysts. The Cr6+ (or Cr5+) species was reduced to an octahedral Cr3+ species by treatment with ethane at 773 K, and the reduced Cr species was reoxidized to the Cr6+ (or Cr5+) species by treatment with CO2 at 673-773 K. The Cr redox cycle played an important role in the catalyst's high activity.

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