EFFICIENT STEREOSELECTIVE SYNTHESIS OF CATECHIN TRIMER DERIVATIVE USING SILVER LEWIS ACID-MEDIATED EQUIMOLAR CONDENSATION

A stereoselective synthesis of benzylated catechin trimer under intermolecular condensasion is achieved using equimolar amount of dimeric catechin nucleophile and monomeric catechin electrophile catalyzed by AgOTf or AgBF(4). The coupled product can be transformed into procyanidin C2 by a known procedure.ArticleHETEROCYCLES. 83(4):739-742 (2011)journal articl

Atomic cluster expansion force field based thermal property material design with density functional theory level accuracy in non-equilibrium molecular dynamics calculations over sub-million atoms

Non-equilibrium molecular dynamics (NEMD) techniques are widely used for investigating lattice thermal conductivity. Recently, machine learning force fields (MLFFs) have emerged as a promising approach to enhance the precision in NEMD simulations. This study is aimed at demonstrating the potential of MLFFs in realizing NEMD calculations for large-scale systems containing over 100,000 atoms with density functional theory (DFT)-level accuracy. Specifically, the atomic cluster expansion (ACE) force field is employed, using Si as an example. The ACE potential incorporates 4-body interactions and features a training dataset consisting of 1000 order structures from first-principles molecular dynamics calculations, resulting in a highly accurate vibrational spectrum. Moreover, the ACE potential can reproduce thermal conductivity values comparable with those derived from DFT calculations via the Boltzmann equation. To demonstrate the application of MLFFs to systems containing over 100,000 atoms, NEMD simulations are conducted on thin films ranging from 100 nm to 500 nm, with the 100 nm films exhibiting defect rates of up to 1.5%. The results show that the thermal conductivity deviates by less than 5% from DFT or theoretical results in both scenarios, which highlights the ability of the ACE potential in calculating the thermal conductivity on a large scale with DFT-level accuracy. The proposed approach is expected to promote the application of MLFFs in various fields and serve as a feasible alternative to virtual experiments. Furthermore, this work demonstrates the potential of MLFFs in enhancing the accuracy of NEMD simulations for investigating lattice thermal conductivity for systems with over 100,000 atoms.Comment: 24 pages including with supporting infomatio

Spectrocolorimetric evaluation of repaired articular cartilage after a microfracture

<p>Abstract</p> <p>Background</p> <p>In clinical practice, surgeons differentiate color changes in repaired cartilage compared with surrounding intact cartilage, but cannot quantify these color changes. Objective assessments are required. A spectrocolorimeter was used to evaluate whether intact and repaired cartilage can be quantified.</p> <p>Findings</p> <p>We investigated the use of a spectrocolorimeter and the application of two color models (L* a* b* colorimetric system and spectral reflectance distribution) to describe and quantify articular cartilage. In this study, we measured the colors of intact and repaired cartilage after a microfracture. Histologically, the repaired cartilage was a mixture of fibrocartilage and hyaline cartilage. In the L* a* b* colorimetric system, the L* and a* values recovered to close to the values of intact cartilage, whereas the b* value decreased over time after the operation. Regarding the spectral reflectance distribution at 12 weeks after the operation, the repaired cartilage had a higher spectral reflectance ratio than intact cartilage between wavelengths of 400 to 470 nm.</p> <p>Conclusion</p> <p>This study reports the first results regarding the relationship between spectrocolorimetric evaluation and the histological findings of repair cartilage after a microfracture. Our findings demonstrate the ability of spectrocolorimetric measurement to judge the repair cartilage after treatment on the basis of objective data such as the L*, a* and b* values and the SRP as a coincidence index of the spectral reflectance curve.</p

Successful Endoscopic Resection of an Early Carcinoma of the Duodenum

We describe a patient in whom an early carcinoma of the duodenum was able to be resected endoscopically. A 77-year-old man presented with epigastric pain. Upper gastrointestinal endoscopy revealed a mass in the duodenum, and the patient was admitted. A whitish nodular aggregated lesion, measuring 20 mm in diameter, was found in the second portion of the duodenum. Examination of a biopsy specimen showed a Group III tubular adenoma. Endoscopic ultrasonography showed that the lesion was confined to the mucosa. The large size of the lesion suggested the possibility of malignancy. Endoscopic mucosal resection was therefore performed. Histopathologically, the diagnosis was carcinoma in adenoma. The depth of invasion was mucosal. We conclude that endoscopic muosal resection can be used to treat mucosal lesions arising in the duodenum

AN EFFICIENT SYNTHESIS OF PROCYANIDINS USING EQUIMOLAR CONDENSATION OF CATECHIN AND/OR EPICATECHIN CATALYZED BY YTTERBIUM TRIFLATE

Stereoselective synthesis of catechin and epicatechin dimers under intermolecular condensation of equimolar amount of catechin derivatives catalyzed by Yb(OTf)(3). The coupled products were successfully converted to procyanidins B1, B2, B3, and B4, respectively. Procyanidins B1, B2, B3, and B4 could be used as standard compounds for identifying the polyphenols in natural source.ArticleHETEROCYCLES. 79:549-563 (2009)journal articl