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1.
RSC Adv ; 13(15): 10379-10383, 2023 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-37020882

RESUMEN

The ring-opening polymerization of ß-lactones into polyhydroxyalkanoates (PHA), biodegradable polymers with high molecular weight and narrow polydispersity, is of significant interest. The mononuclear zirconium compound containing sterically hindered N,O-chelate and anionic dimethylamide ligands was used as an initiator for the polymerization of ß-butyrolactone (BBL), resulting in polyhydroxylbutyrate (PHB) with a number-average molecular weight of 12 000 g mol-1. Kinetic studies demonstrate a first-order dependence on ß-butyrolactone (BBL) concentration at room temperature, accompanied by narrow molecular weight distributions (ca. 1.03-1.07), indicating a well-controlled living polymerization.

2.
Langmuir ; 39(14): 4984-4992, 2023 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-36947443

RESUMEN

Extreme gradient boosting (XGBoost) is an artificial intelligence algorithm capable of high accuracy and low inference time. The current study applies this XGBoost to the production of platinum nano-film coating through atomic layer deposition (ALD). In order to generate a database for model development, platinum is coated on α-Al2O3 using a rotary-type ALD equipment. The process is controlled by four parameters: process temperature, stop valve time, precursor pulse time, and reactant pulse time. A total of 625 samples according to different process conditions are obtained. The ALD coating index is used as the Al/Pt component ratio through ICP-AES analysis during postprocessing. The four process parameters serve as the input data and produces the Al/Pt component ratio as the output data. The postprocessed data set is randomly divided into 500 training samples and 125 test samples. XGBoost demonstrates 99.9% accuracy and a coefficient of determination of 0.99. The inference time is lower than that of random forest regression, in addition to a higher prediction safety than that of the light gradient boosting machine.

3.
J Org Chem ; 88(8): 5127-5134, 2023 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-36649592

RESUMEN

A phenanthroline-based porous organic polymer-supported heterogeneous Pd catalyst (Pd@Phen-POP) is facilely synthesized by the solvent knitting of a Phen scaffold via the Lewis-acid-catalyzed Friedel-Crafts reaction using dichloromethane as a source for linker in the presence of AlCl3. The catalyst very effectively catalyzes the alkoxycarbonylation of various substituted aryl iodides with various alcohols to give corresponding products in good to excellent yields. Owing to the heterotic nature of the catalyst, it can be easily separated by simple filtration from the reaction mixture and recycled.

4.
Materials (Basel) ; 15(12)2022 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-35744248

RESUMEN

Silicon-based anodes can increase the energy density of Li-ion batteries (LIBs) owing to their large weights and volumetric capacities. However, repeated charging and discharging can rapidly deteriorate the electrochemical properties because of a large volume change in the electrode. In this study, a commercial Fe-Si powder was coated with Al2O3 layers of different thicknesses via atomic layer deposition (ALD) to prevent the volume expansion of Si and suppress the formation of crack-induced solid electrolyte interfaces. The Al2O3 content was controlled by adjusting the trimethyl aluminum exposure time, and higher Al2O3 contents significantly improved the electrochemical properties. In 300 cycles, the capacity retention rate of a pouch full-cell containing the fabricated anodes increased from 69.8% to 72.3% and 79.1% depending on the Al2O3 content. The powder characterization and coin and pouch cell cycle evaluation results confirmed the formation of an Al2O3 layer on the powder surface. Furthermore, the expansion rate observed during the charging/discharging of the pouch cell indicated that the deposited layer suppressed the powder expansion and improved the cell stability. Thus, the performance of an LIB containing Si-alloy anodes can be improved by coating an ALD-synthesized protective Al2O3 layer.

5.
Inorg Chem ; 61(15): 5683-5690, 2022 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-35389623

RESUMEN

Regeneration of nicotinamide adenine dinucleotide (NADH) has been the primary interest in the field of enzymatic transformation, especially associating oxidoreductases given the stoichiometric consumption. The synthesized carbene-ligated rhodium complex [(η5-Cp*)Rh(MDI)Cl]+ [Cp* = pentamethylcyclopentadienyl; MDI = 1,1'-methylenebis(3,3'-dimethylimidazolium)] acts as an exceptional catalyst in the reduction of NAD+ to NADH with a turnover frequency of 1730 h-1, which is over twice that of the higher catalytic activity of the commercially available catalyst [Cp*Rh(bpy)Cl]+ (bpy = 2,2'-bipyridine). Offsetting the contentious atmosphere currently taking place over the specific intermediate of the NADH regeneration, this study presents pivotal evidence of a metal hydride intermediate with a bis(carbene) ligand: a stable form of the rhodium hydride intermediate, [(η5-Cp*)Rh(MDI)H]+, was isolated and fully characterized. This enables thorough insight into the possible mechanism and exact intermediate structure in the NAD+ reduction process.


Asunto(s)
Rodio , Metano/análogos & derivados , NAD/química , Oxidación-Reducción , Regeneración , Rodio/química
6.
Dalton Trans ; 51(13): 5315-5321, 2022 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-35293395

RESUMEN

A zirconium complex containing an N,O-chelate and alkylamide ligand has great potential for application in atomic layer deposition (ALD). However, the synthesis of this mononuclear Zr complex remains a major challenge because of the highly electrophilic nature and rich coordination of the Zr(IV) atom. Herein, a nonclassical and highly effective route for synthesizing the mononuclear N,O-chelate Zr complex was envisaged and verified using rationally designed reactions, involving the ring-opening insertion of epoxide into tetrakis(dimethylamido)zirconium(IV) (TDMAZ) at room temperature. To the best of our knowledge, very few studies in which mononuclear Zr complexes comprising alkylamide in combination with aminoalkoxide are structurally characterized. This method is extremely simple, atom economical, and easily scalable. Importantly, the produced precursor complex enables ALD of ZrO2 at a satisfactory growth rate (0.93 Å per cycle), close to that of the commercial ALD precursor CpZr(NMe2)3 (0.9 Å per cycle).

7.
Materials (Basel) ; 15(3)2022 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-35160706

RESUMEN

Among silicone oligomers, polydimethylsiloxane (PDMS) is widely used industrially and has the advantage of improving the properties of other compounds, such as flame-retardant polyurethane (PU). However, as there are barriers to the synthesis of PU-grafted siloxane, owing to the polarity difference between isocyanate and PDMS, numerous research efforts are being aimed at improving the hydrophilicity of PDMS. To improve the hydrophilicity and reactivity of hydroxyl PDMS, bis(propane-1,2-diol)-terminated PDMS (G-PDMS-G) with four hydroxy (-OH) groups was synthesized through ring-opening addition to replace both ends of linear α,ω-hydroxyl PDMS (HO-PDMS-OH) with glycidol, resulting in hydrophilic PDMS rather than dihydroxy PDMS. In all cases of G-PDMS-G, the contact angle and viscosity both decreased by more than 20%, confirming the improved hydrophilicity. In particular, G-PDMS-G-3, which has the largest molecular weight, demonstrated the greatest decrease in viscosity and contact angle (33%).

8.
Inorg Chem ; 61(3): 1552-1561, 2022 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-34989233

RESUMEN

The reductive carbonylation of nitroarenes in the presence of MeOH and CO(g) is one of the interesting alternative routes without utilizing toxic phosgene and corrosive HCl generation for the synthesis of industrially useful carbamate compounds that serve as important intermediates for polyurethane production. Since homogeneous palladium catalysts supported by phen (phen = 1,10-phenanthroline) are known to be effective for this catalysis, the heterogenized Pd catalyst was developed using the phen-containing solid support. In this study, we report the synthesis of a phen-based heterogeneous Pd catalyst, Pd@phen-POP, which involves the solvent knitting of a phen scaffold via the Lewis-acid-catalyzed Friedel-Crafts reaction using dichloromethane as a source for linker in the presence of AlCl3 as a catalyst. The resulting solid material has been thoroughly characterized by various physical methods revealing high porosity and surface area. Similar to the homogeneous pallidum catalyst, this heterogeneous catalyst shows efficient reductive carbonylation of various nitroarenes. The catalytic reaction using nitrobenzene as a model compound presents a high turnover number (TON = 530) and a reasonable turnover frequency (TOF = 45 h-1), with a high selectivity (92%) for the carbamate formation. According to the recycling study, the heterogeneous catalyst is recyclable and retains ∼90% of the original reactivity in each cycle.

9.
Chem Sci ; 12(10): 3551-3557, 2021 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-34163628

RESUMEN

We investigate oxidative methane activation on a wide range of single transition metal atom catalysts embedded on N-doped graphene derivatives using density functional theory calculations. An inverse scaling relationship between *O formation and its hydrogen affinity is observed, consistent with a previous report. However, we find that the latter scaling line can be shifted towards a more reactive region by tuning the coordination number (CN) of the active metal sites. Specifically, we find that lowering the CN plays an important role in increasing the reactivity for methane activation via a radical-like transition state by moving the scaling lines. Thus, in the new design strategy suggested here, different from the conventional efforts focusing mainly on breaking the scaling relations, one maintains the scaling relations but moves them towards more reactive regions by controlling the coordination number of the active sites. With this design principle, we suggest several single atom catalysts with lower C-H activation barriers than some of the most active methane activation catalysts in the literature such as Cu-based zeolites.

10.
World J Clin Cases ; 9(8): 2015-2021, 2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-33748255

RESUMEN

BACKGROUND: The roots of Achyranthes japonica Nakai (AJN), called "Useul-puli," has been traditionally used to control pain and improve dysfunction in osteoarthritis patients in South Korea. CASE SUMMARY: We described 3 patients diagnosed with herbal medicine induced interstitial lung disease after consuming boiled the roots of AJN. They were referred to our hospital because of the modified Medical Research Council grade 4 dyspnea. Chest computed tomography showed bilateral ground-glass opacities with patchy consolidation. After treatment with systemic glucocorticoid therapy and discontinuation of the roots of AJN, their symptoms improved, and almost all ground-glass opacities and patchy consolidations on chest radiography and chest computed tomography resolved. CONCLUSION: We present three cases of interstitial lung disease induced by the roots of AJN.

11.
Inorg Chem ; 60(10): 6881-6888, 2021 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-33576602

RESUMEN

In this study, a commercially available homogeneous pincer-type complex, Ru-Macho, was directly heterogenized via the Lewis acid-catalyzed Friedel-Crafts reaction using dichloromethane as the cross-linker to obtain a heterogeneous, pincer-type Ru porous organometallic polymer (Ru-Macho-POMP) with a high surface area. Notably, Ru-Macho-POMP was demonstrated to be an efficient heterogeneous catalyst for the chemoselective hydrogenation of α,ß-unsaturated carbonyl compounds to their corresponding allylic alcohols using cinnamaldehyde as a model compound. The Ru-Macho-POMP catalyst showed a high turnover frequency (TOF = 920 h-1) and a high turnover number (TON = 2750), with high chemoselectivity (99%) and recyclability during the selective hydrogenation of α,ß-unsaturated carbonyl compounds.

12.
Respir Med Case Rep ; 31: 101225, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33005565

RESUMEN

Pulmonary pleomorphic carcinoma (PPC) is a poorly differentiated non-small cell lung carcinoma, including squamous cell carcinoma, adenocarcinoma, or undifferentiated non-small cell lung carcinoma with at least 10% spindle and/or giant cells. Here, we report a case of PPC showing undifferentiated non-small cell lung carcinoma with giant cells. A 71-year-old man with dyspnea underwent right lobectomy because of a mass in the right upper lobe of the lung. A 5.0 × 3.0 × 1.5 cm-sized tumor was identified; microscopically, the tumor composed of undifferentiated large sized tumor cells admixed with syncytial tumor giant cells and emperipoletic giant cells. Immunohistochemically, the tumor cells were reactive for pan-cytokeratin, but negative for P40, thyroid transcription factor 1 (TTF-1), and vimentin. The tumor cells were also positive for 3 clones of programmed death-ligand 1 (PD-L1). The clinical and histologic findings supported the diagnosis of an undifferentiated non-small cell lung carcinoma with giant cells, which is a subtype of pulmonary pleomorphic carcinoma. Unfortunately, after surgery, multifocal lymph node metastasis was identified in radiologic examination. Only palliative chemotherapy was administered to the patient, although he was indicated for immunochemotherapy. Pulmonary pleomorphic carcinoma is known to have a poor prognosis, even in early stages of the disease, therefore, we should be careful in the diagnosis to ensure optimal treatment.

13.
Sci Rep ; 10(1): 13127, 2020 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-32753578

RESUMEN

Diffuse optical tomography (DOT) non-invasively measures the functional characteristics of breast lesions using near infrared light to probe tissue optical properties. This study aimed to evaluate a new digital breast tomosynthesis (DBT)/DOT fusion imaging technique and obtain preliminary data for breast cancer detection. Twenty-eight women were prospectively enrolled and underwent both DBT and DOT examinations. DBT/DOT fusion imaging was created after acquisition of both examinations. Two breast radiologists analyzed DBT and DOT images independently, and then finally evaluated the fusion images. The diagnostic performance of each reading session was compared and interobserver agreement was assessed. The technical success rate was 96.4%, with one failure due to an error during DOT data storage. Among the 27 women finally included in the analysis, 13 had breast cancer. The areas under the receiver operating characteristic curve (AUCs) for DBT were 0.783 and 0.854 for readers 1 and 2, respectively. DOT showed comparable diagnostic performance to DBT for both readers. The AUCs were significantly improved (P = 0.004) when the DBT/DOT fusion images were used. Interobserver agreements were highest for the DBT/DOT fusion images. In conclusion, this study suggests that DBT/DOT fusion imaging technique appears to be a promising tool for breast cancer diagnosis.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador , Mamografía , Tomografía Óptica , Adulto , Femenino , Humanos , Persona de Mediana Edad
14.
Inorg Chem ; 59(5): 2881-2889, 2020 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-32048846

RESUMEN

Salen and salphens are important ligands in coordination chemistry due to their ability to form various metal complexes that can be used for a variety of organic transformations. However, salen/salphen complexes are difficult to separate from the reaction mixture, thereby limiting their application to homogeneous systems. Accordingly, considerable effort has been spent to heterogenize the metallosalen/salphen complexes; however, this has resulted in compromised activities and selectivities. Direct heterogenization of metallosalens to form porous organic polymers (POPs) shows promise for heterogeneous catalysis, because it would allow easy separation while retaining catalytic function. Thus, a facile synthetic strategy for preparing metallosalen/salphen-based porous organic polymers through direct molecular knitting using a Friedel-Crafts reaction is presented herein for the first time. As representative candidates, salphenM(III)Cl (M = Al3+ and Cr3+) complexes are knitted by covalent cross-linking using this facile, scalable, one-pot method to synthesize highly POPs in high yields. When incorporated with [Co(CO)4]- anions, the resulting heterogeneous Lewis acidic metal (Al3+ and Cr3+) POPs exhibit propylene oxide ring-expansion carbonylation activity on par with those of their homogeneous counterparts.

15.
ChemSusChem ; 13(7): 1735-1739, 2020 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-31970875

RESUMEN

In the context of CO2 utilization, a number of CO2 conversion methods have been identified in laboratory-scale research; however, only a very few transformations have been successfully scaled up and implemented industrially. The main bottleneck in realizing industrial application of these CO2 conversions is the lack of industrially viable catalytic systems and the need for practically implementable process developments. In this study, a simple, highly efficient and recyclable ruthenium-grafted bisphosphine-based porous organic polymer (Ru@PP-POP) catalyst has been developed for the hydrogenation of CO2 to N,N-dimethylformamide, which affords a highest ever turnover number of 160 000 and an initial turnover frequency of 29 000 h-1 in a batch process. The catalyst is successfully applied in a trickle-bed reactor and utilized in an industrially feasible continuous-flow process with an excellent durability and productivity of 915 mmol h-1 gRu -1 .

16.
Int J Syst Evol Microbiol ; 70(2): 721-731, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31833829

RESUMEN

Strain F21T, a marine, aerobic, Gram-negative, rod-shaped bacterium, was isolated from seashore sand sampled in Pohang, Republic of Korea. Cells of strain F21T were non-motile, catalase-positive, oxidase-positive, non-spore-forming and formed pinkish-red colonies on marine agar. The strain grew optimally at 37°C, pH 7 and in the presence of 2-3 % NaCl (w/v). Analysis of the 16S rRNA gene sequence of strain F21T revealed that it belonged to the genus Algoriphagus, family Cyclobacteriaceae, with similarity values of 98.1 and 96.8 % to Algoriphagus marincola DSM 16067T and Algoriphagus ornithinivorans IMSNU 14014T, respectively. When comparing the genome sequence of F21 T with those of the type strains of six species of the genus Algoriphagus, the values obtained were below the thresholds for analyses of average nucleotide identity (71.8-92.7 %) and in silico DNA-DNA hybridization using the Genome-to-Genome Distance Calculator (14.7-75.2 %). The DNA G+C content of strain F21T was 42.0 mol%. The chemotaxonomic characteristics of F21T included MK-7 as the predominant isoprenoid quinone, iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) as major cellular fatty acids, and phosphatidylcholine and phosphatidylethanolamine as major polar lipids. On the basis of phenotypic and chemotaxonomic properties, phylogenetic distinctiveness, and genomic data, we named strain F21T as Algoriphagus aquimaris sp. nov. and proposed that strain F21T (=KEMB 2250-007T= KCTC 72106T=JCM 33187T) in the genus Algoriphagus represents a novel species.


Asunto(s)
Bacteroidetes/clasificación , Filogenia , Arena/microbiología , Técnicas de Tipificación Bacteriana , Bacteroidetes/aislamiento & purificación , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Hibridación de Ácido Nucleico , Fosfolípidos/química , Pigmentación , ARN Ribosómico 16S/genética , República de Corea , Agua de Mar/microbiología , Análisis de Secuencia de ADN , Vitamina K 2/análogos & derivados , Vitamina K 2/química
17.
ACS Appl Mater Interfaces ; 11(20): 18609-18616, 2019 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-31039304

RESUMEN

Development of an industrially viable catalyst for the ring-expansion carbonylation of epoxides remains challenging in the view of facile product separation and recyclability. Herein, we report a heterogenized porous porphyrin Al(III) tetracarbonylcobaltate bimetallic catalyst for the ring-expansion carbonylation of epoxides. The catalyst was synthesized using a hyper-cross-linking strategy involving methylene bridges introduced by the Friedel-Crafts reaction and incorporated with cobaltate anions. The catalyst effectively converts epoxides into the corresponding ß-lactones with an excellent site time yield of 360 h-1, which is comparable to that of the corresponding homogeneous catalysts and is the highest of any heterogeneous catalyst reported so far for this reaction.

18.
Food Sci Anim Resour ; 39(1): 54-64, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30882074

RESUMEN

Wet and dry aging methods were applied to improve the quality of three different beef cuts (butt, rump, and sirloin) from Hanwoo cows (quality grade 2, approximately 50-mon-old). After 28 d of wet aging (vacuum packaged; temperature, 2±1°C) and dry aging (air velocity, 2-7 m/s; temperature, 1±1°C; humidity, 85±10%), proximate composition, cooking loss, water holding capacity, shear force, color, nucleotides content, and sensory properties were compared with a non-aged control (2 d postmortem). Both wet and dry aging significantly increased the water holding capacity of the butt cuts. Dry aging in all beef cuts induced lower cooking loss than that in wet-aged cuts. Shear force of all beef cuts was decreased after both wet and dry aging and CIE L*, a*, and b* color values in butt and sirloin cuts were higher in both wet and dry aging (p<0.05) groups than those in the non-aged control. Regardless of the aging method used, inosine-5'-monophosphate content among beef cuts was the same. The sensory panel scored significantly higher values in tenderness, flavor, and overall acceptability for dry-aged beef regardless of the beef cuts tested compared to non- and wet-aged cuts. In addition, dry-aged beef resulted in similar overall acceptability among the different beef cuts, whereas that in wet-aged meat was significantly different by different beef cuts. In conclusion, both wet and dry aging improved the quality of different beef cuts; however, dry aging was more suitable for improving the quality of less preferred beef cuts.

19.
Inorg Chem ; 58(6): 3717-3723, 2019 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-30821970

RESUMEN

Today, one of the most imperative targets to realize the conversions of CO2 in industry is the development of practically viable catalytic systems that demonstrate excellent activity, selectivity, and durability. Herein, a simple heterogeneous Ru(III) catalyst is prepared by immobilizing commercially available RuCl3· xH2O onto a bipyridine-functionalized covalent triazine framework, [bpy-CTF-RuCl3], for the first time. This novel catalyst efficiently hydrogenates CO2 into formate with an unprecedented turnover frequency (38800 h-1) and selectivity. In addition, the catalyst excellently maintains its efficiency over successive runs and produces a maximum final formate concentration of ∼2.1 M in just 2.5 h with a conversion of 12% in regard to CO2 feed. The apparent advantages of air stability, ease of handling, simplicity, the use of a readily available metal precursor, and the outstanding catalytic performance make [bpy-CTF-RuCl3] one of the possible candidates for realizing the large-scale production of formic acid/formate by CO2 hydrogenation.

20.
J Nanosci Nanotechnol ; 19(7): 4282-4286, 2019 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-30765006

RESUMEN

In this study, the effects of etching time and temperature on the adhesion of plated layers of acrylonitrile butadiene styrene (ABS) were investigated. The ABS surface micropores, which act as anchors to improve the adhesion of the plated layer, increased in numbers as the etching temperature increased. Adhesion was maximum at the etching time of 9 min at etching temperatures of 60 and 70 °C. For the etching times of 12 and 15 min, micropores on the ABS surface were incompletely filled during electroplating because the pores were both deep and narrow. The adhesion strength was decreased by these unfilled micropores, which further reduced the anchor effect. The ratio of the increased surface area ratio of the ABS to that of the plated surface was maximized at 9 min etching time, at which point the plating adhesion was also maximized.

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