{"title":"Theoretical Study on TiOOH Production over Au/TiO<sub>2</sub> Catalyst — Support Dependency of Propylene Oxide Production—","authors":"Yasutaka Hamada, Yuki Mishima, Tomohisa Yonemori, Takashi Kawakami, Shusuke Yamanaka, Mitsutaka Okumura","doi":"10.1246/cl.230367","DOIUrl":"https://doi.org/10.1246/cl.230367","url":null,"abstract":"Au supported anatase TiO2 enables the selective synthesis of propylene oxide from propylene using O2 and H2. However, this reaction does not proceed on Au supported rutile TiO2. The origin of this difference in the catalytic activity was examined using DFT calculations. DFT calculations revealed that the stability of the TiOOH active species was directly related to the product selectivity. Au supported anatase TiO2 enables the selective synthesis of propylene oxide from propylene using O2 and H2, while this reaction does not proceed on Au supported rutile TiO2. This difference of the catalytic activity was examined using DFT calculation. From the calculation results, it was found that the stability of TiOOH is directly related to the product selectivity.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135252067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Selective Self-Assembly of Gold Nanocrystals using Complementary Leucine Zipper Peptides","authors":"Issei Nakao, Kento Sumida, Mizuki Kitamatsu, Tetsuro Soejima","doi":"10.1246/cl.230379","DOIUrl":"https://doi.org/10.1246/cl.230379","url":null,"abstract":"A heterodimeric leucine zipper (Lz)–based peptide hybrid was utilized as a molecular adhesive to bound two types of gold nanocrystals with different shapes. An acidic leucine zipper (LzE) and a basic leucine zipper (LzK) peptides with terminal cysteine are respectively adsorbed to the surface of spherical gold nanoparticles (LzE–Au NPs) and gold nanocubes (LzK–Au NCs). Transmission electron microscope (TEM) observation and visible (Vis) absorption spectroscopy were revealed that LzE–Au NPs and LzK–Au NCs are selectively self-assembled in water. The dynamic self-assembly behavior is also confirmed by in-situ fluorescence resonance energy transfer between fluorescence dyes connected to LzE and LzK peptides and other control experiments. Complementary acidic leucine zipper (LzE) and basic leucine zipper (LzK) peptides were successfully adsorbed to the surface of spherical gold nanoparticles (Au NPs) and gold nanocubes (Au NCs), respectively. Selective self-assembly of LzE–Au NPs and LzK–Au NCs was occurred by hydrophobic interaction between leucine residues and electrostatic interaction between K (Lys) and E (Glu) amino acids.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135303452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Novel Characteristic of a Water-soluble UV-B Absorber, 2-Phenylbenzimidazole-5-sulfonic Acid: Suppression of Riboflavin-sensitized Singlet Oxygen Generation","authors":"Soichiro Hisanaga, Kazuyuki Miyazawa, Mikio Yagi, Azusa Kikuchi","doi":"10.1246/cl.230330","DOIUrl":"https://doi.org/10.1246/cl.230330","url":null,"abstract":"2-Phenylbenzimidazole-5-sulfonic acid (PBSA) is a water-soluble UV-B absorber used in cosmetic sunscreens. Riboflavin (RF) is a water-soluble vitamin B2. RF is an efficient singlet oxygen photosensitizer. The effects of PBSA on RF-photosensitized singlet oxygen generation have been studied through measurements of transient absorption and time-resolved near-IR phosphorescence in phosphate buffer (pH 7.4). PBSA suppresses the RF-photosensitized singlet oxygen generation. The observed suppression can be ascribed to the quenching of the lowest excited triplet state of RF by PBSA. 2-Phenylbenzimidazole-5-sulfonic acid (PBSA) is a water-soluble UV-B absorber used in cosmetic sunscreens. Riboflavin (RF) is a water-soluble vitamin B2. RF is an efficient singlet oxygen photosensitizer. The effects of PBSA on RF-photosensitized singlet oxygen generation have been studied through measurements of transient absorption and time-resolved near-IR phosphorescence in phosphate buffer (pH 7.4). PBSA suppresses the RF-photosensitized singlet oxygen generation.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135547607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Au/Nb<sub>2</sub>O<sub>5</sub>-Catalyzed <i>N</i>-Formylation of Amines Utilizing High Selectivity to Formate Intermediate in CO<sub>2</sub> Hydrogenation","authors":"Mitsuyo Hidaka, Mingyue Lin, Hiroki Yamakawa, Akihiro Nakayama, Toru Murayama, Tetsuya Shimada, Shinsuke Takagi, Tamao Ishida","doi":"10.1246/cl.230365","DOIUrl":"https://doi.org/10.1246/cl.230365","url":null,"abstract":"Deformed orthorhombic niobium oxide-supported Au nanoparticles (Au/Nb2O5-DO) exhibited high catalytic activity for N-formylation of amines using CO2 and H2 compared to other Au/Nb2O5 catalysts having different crystalline structures. Au/Nb2O5-DO also showed high selectivity to methyl formate in CO2 hydrogenation. Nb2O5-DO possessed greater amount of acid sites than Au/Nb2O5-T (orthorhombic) and Au/Nb2O5-A (amorphous), which would be beneficial for the formate activation and amine adsorption. Deformed orthorhombic niobium oxide-supported Au nanoparticles (Au/Nb2O5-DO) exhibited high catalytic activity for N-formylation of amines using CO2 and H2 compared to other Au/Nb2O5 catalysts having different crystalline structures. Au/Nb2O5-DO also showed high selectivity to formate in CO2 hydrogenation. Nb2O5-DO possessed greater amount of acid sites than Au/Nb2O5-T (orthorhombic) and Au/Nb2O5-A (amorphous), which would be beneficial for the formate activation and amine adsorption.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Wrapping of Drug Assembly with Silica Layer and Confinement through Reversible Linkage with Copper(II) for Glutathione-Responsive Nanocapsule","authors":"Hideki Matsune, Ryoya Yoshida, Ren Ikemizu, Koichiro Shiomori, Tsuyoshi Yamamoto, Masahiro Kishida","doi":"10.1246/cl.230322","DOIUrl":"https://doi.org/10.1246/cl.230322","url":null,"abstract":"Colloidal nano-assembly containing doxorubicin (DOX) is prepared for the first time by co-precipitation with gluconate. The spherical assembly is wrapped with a porous silica layer via sol-gel process, and confined in the formed cage by treatment with copper(II) ions (Cu2+). The reversible linking of DOX with Cu2+ is allowed to suppress the leakage of DOX, but the quick release is turned on in response to glutathione (GSH). The synthesized stimulus-responsive nanocapsules are characterized, and examined in the release test with/without GSH and applied to living HeLa cells. Spherical molecular assembly containig doxorubicin (DOX) is prepared by co-precipitatinon of doxorubicin hydrochloride and sodium gluconate (NaGlc), and then wrapped with porous silica layer via sol-gel process. The permeation of Cu2+ is allowed to suppress the leaking of the contents due to the blocking of the microchannels in the surronding layer, but release DOX immediately in response to glutathione (GSH).","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134947749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mayu Shono, Fumika Fujita, Kenichi Yoshikawa, Akihisa Shioi
{"title":"Stabilization of DNA-encapsulating Droplets through Negative Charge at the Droplet Interface","authors":"Mayu Shono, Fumika Fujita, Kenichi Yoshikawa, Akihisa Shioi","doi":"10.1246/cl.230294","DOIUrl":"https://doi.org/10.1246/cl.230294","url":null,"abstract":"It was found that stable cell-sized droplets entrapping DNA molecules are spontaneously generated through micro segregation. To clarify the mechanism, we performed measurements of the electrification by adapting a polymer solution with polyethylene glycol/dextran. We determined the Donnan potential for macroscopic phase segregation in both the presence and absence of DNA, together with the measurements of Zeta potentials of the microphase solution with number of small droplets. We confirmed that the droplets entrapping DNA are negatively charged. Stable cell-sized droplets entrapping DNA are spontaneously generated through micro segregation of polyethylene glycol/dextran solution. To clarify the mechanism, we determined the Donnan potential for macroscopic phase segregation in both with and without DNA, together with the Zeta potential measurements of the microphase solution with number of small droplets. We confirmed that the DNA-encapsulating droplets are negatively charged.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135547606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quan Zou, Akiyoshi Kuzume, Masataka Yoshida, Takane Imaoka, Kimihisa Yamamoto
{"title":"Machine Learning Accelerated Discovery of Subnanoparticles for Electrocatalytic Hydrogen Evolution","authors":"Quan Zou, Akiyoshi Kuzume, Masataka Yoshida, Takane Imaoka, Kimihisa Yamamoto","doi":"10.1246/cl.230310","DOIUrl":"https://doi.org/10.1246/cl.230310","url":null,"abstract":"Metal and alloy subnanoparticles (SNPs) have been anticipated to be a class of promising catalysts because of their fundamental difference from nanoparticles (NPs). In general, the interaction among the surface and bulk atoms of SNPs is significant due to the higher degree of alloying in SNPs than that in NPs counterparts. This study compared the SNPs and NPs concerning their electrocatalytic activities of hydrogen evolution reaction (HER) to understand the essential difference between alloy SNPs and NPs by using machine learning. Phase segregation does not occur on multimetallic subnanoparticles (SNPs), but easily occurs on nanoparticles (NPs), which led to the homogeneously alloying of SNPs and unpredictable phase segregation of NPs. Because of this distinct behavior between SNPs and NPs, the HER activity of SNPs should be easier to predict than NPs. Therefore, machine learning was applied to accelerate the discovery of SNPs.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135547243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yaw Amo Wiafe, Emmanuel Acheamfour-Akowuah, Isaac Kofi Owusu
{"title":"Indications for echocardiography and confirmation rates of cardiovascular diseases: experience of a specialist cardiac outpatient clinic in Kumasi, Ghana.","authors":"Yaw Amo Wiafe, Emmanuel Acheamfour-Akowuah, Isaac Kofi Owusu","doi":"10.4103/aam.aam_151_22","DOIUrl":"10.4103/aam.aam_151_22","url":null,"abstract":"<p><strong>Background: </strong>Transthoracic echocardiography is a very helpful noninvasive cardiovascular imaging technique for the diagnosis and risk stratification in the management of patients with cardiovascular diseases. We aimed to review the clinical indications for transthoracic echocardiography and the confirmation rate of cardiovascular diseases by echocardiography at a specialist cardiac clinic in Ghana.</p><p><strong>Methods: </strong>Using a cross-sectional study design, the echocardiography reports of all patients above the age of 15 who were assessed at the clinic were analyzed. Data on patient demographics, clinical history, clinical indication for echocardiography, and the echocardiographic findings were analyzed using version 25.0 of the Statistical Package for Social Sciences (SPSS).</p><p><strong>Results: </strong>A total of 594 participants were studied. The age range of participants was 15-96 years, with a mean (± standard deviation) age of 53.72 (± 17.25) years. There were more females (50.17%) than males (49.83%). Most (54.21%) of the participants had echocardiography for cardiac evaluation. Other indications included hypertension/hypertensive heart disease (HHD) (n = 131; 22.06%), heart failure (n = 69; 11.62%), chest pains (n = 12; 2.02%), and valvular heart disease (VHD) (n = 11; 1.85%). Three hundred and eight-nine (70.30%) of the participants had their clinical diagnoses confirmed by echocardiography; echocardiographic confirmation rates for heart failure, VHD, and HHD were 92.75%, 90.91%, and 88.54%, respectively.</p><p><strong>Conclusion: </strong>Echocardiography showed high confirmation rates for our patients with heart failure, VHD, and HHD. Prompt usage of this noninvasive cardiovascular imaging for the initial evaluation of patients with cardiovascular diseases is highly recommended.</p>","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"4 1","pages":"440-445"},"PeriodicalIF":0.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10775930/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88490250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Antibacterial rattle-type polypyrrole-silver nanocomposite particles synthesized by aqueous chemical oxidative dispersion polymerization","authors":"Nattawut Rodtuk, Kazusa Takeuchi, Tomoyasu Hirai, Yoshinobu Nakamura, Warayuth Sajomsang, Preeyaporn Chaiyasat, Amorn Chaiyasat, Syuji Fujii","doi":"10.1246/cl.230318","DOIUrl":"https://doi.org/10.1246/cl.230318","url":null,"abstract":"Rattle-type polypyrrole-silver nanocomposite particles were synthesized by aqueous chemical oxidative dispersion polymerization in one step and one pot manner and were characterized in terms of particle size, morphology and chemical composition. The resulting nanocomposite particles could function as an antibacterial agent against Staphylococcus aureus and Escherichia coli. Rattle-type polypyrrole-silver nanocomposite particles were synthesized by aqueous chemical oxidative dispersion polymerization in one step and one pot manner and were characterized in terms of particle size, morphology and chemical composition. The resulting nanocomposite particles could function as an antibacterial agent against Staphylococcus aureus and Escherichia coli.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136279027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Effect of Mixed Ligands on the Polymerization Rate of SET-LRP in Aqueous Solution","authors":"Xiaojing Feng, Wenxia Yuan","doi":"10.1246/cl.230355","DOIUrl":"https://doi.org/10.1246/cl.230355","url":null,"abstract":"The mixed-ligand effect is investigated in single electron transfer-living radical polymerization (SET-LRP) of OEOMA in aqueous solution for the first time. Mediated by equimolar of tris(2-aminoethyl)amine (TREN) and tris(dimethylaminoethyl)amine (Me6-TREN), SET-LRP exhibits the highest polymerization rate while maintains living characteristics. The higher concentration of self-assembled micellar particles formed by amphiphilic initiator and monomer in aqueous solution under the influence of mixed ligands may be considered as one of factors for the mixed-ligand effect. A mixed-ligand effect is observed at 1:1 molar combination of tris(2-dimethylaminoethyl)amine (Me6-TREN) with tris(2-aminoethyl)amine (TREN) during Cu(0) wire-catalyzed single-electron transfer-living radical polymerization (SET-LRP) of OEOMA initiated with PEG-derived initiator in aqueous solution. A higher concentration of self-assembled micellar particles of monomer (or initiator) is proposed as one of the reasons for the mixed-ligand effect.","PeriodicalId":9862,"journal":{"name":"Chemistry Letters","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135132675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}