RESUMO
Chip-scale optical devices operated at wavelengths shorter than communication wavelengths, such as LiDAR for autonomous driving, bio-sensing, and quantum computation, have been developed in the field of photonics. In data processing involving optical devices, modulators are indispensable for the conversion of electronic signals into optical signals. However, existing modulators have a high half-wave voltage-length product (VπL) which is not sufficient at wavelengths below 1000 nm. Herein, we developed a significantly efficient optical modulator which has low VπL of 0.52 V·cm at λ = 640 nm using an electro-optic (EO) polymer, with a high glass transition temperature (Tg = 164 °C) and low optical absorption loss (2.6 dB/cm) at λ = 640 nm. This modulator is not only more efficient than any EO-polymer modulator reported thus far, but can also enable ultra-high-speed data communication and light manipulation for optical platforms operating in the ranges of visible and below 1000 nm infrared.
RESUMO
A convenient asymmetric reductive amination of benzylic ketones (α-arylated ketones) catalyzed by newly designed Cp*Ir complexes bearing a chiral N-(2-picolyl)sulfonamidato ligand was developed. Using readily available ß-amino alcohols as chiral aminating agents, a range of benzo-fused and acyclic ketones were successfully reduced with formic acid in methanol at 40 °C to afford amines with favorable chemo- and diastereoselectivities. The amino alcohol-derived chiral auxiliary was easily removed by mild periodic oxidants, leading to optically active primary ß-arylamines without erosion of the optical purity (up to 97% ee). The excellent catalytic performance was retained even upon lowering the amount of catalyst to a substrate/catalyst (S/C) ratio of 20,000, and the amination could be performed on a large scale exceeding 100 g. The precise hydride transfer to iminium species generated from the ketonic substrate and the chiral amine counterpart was suggested by the mechanistic studies on stoichiometric reactions of isolable hydridoiridium complexes and model intermediates such as N,O-acetal, enamine, and iminium compounds.
RESUMO
Cp*Ir complexes bearing a 2-picolinamide moiety serve as effective catalysts for the direct reductive amination of ketonic compounds to give primary amines under transfer hydrogenation conditions using ammonium formate as both the nitrogen and hydrogen source. The clean and operationally simple transformation proceeds with a substrate to catalyst molar ratio (S/C) of up to 20,000 at relatively low temperature and exhibits excellent chemoselectivity toward primary amines.
RESUMO
We propose a method for calculating the work of adhesion between a liquid and solid surface by using molecular simulations. Two ideas are introduced for efficient calculation when the proposed method is applied at the interface between a liquid and a polymer-grafted substrate. First, the liquid molecules are separated from the solid surface based on its shape by placing spherically symmetric potentials around the atoms selected from the substrate and the polymers grafted onto it. Second, to avoid deterioration of accuracy during numerical integration of the work, the parameters that appear in the potential are updated so that variations in the gradient of the work are suppressed. This method is applied to the interface between water and a gold substrate modified by poly(ethylene oxide) (PEO), and it is found that the work of adhesion is greater at intermediate PEO densities.
RESUMO
The recommended dose of imatinib for recurrent gastrointestinal stromal tumors (GIST) is 400mg/day. However, adverse effects limit the use of the standard dose in elderly patients. We report a case of an elderly patient with recurrent GIST, where long-term control of the disease was achieved with low-dose imatinib therapy. An 86-year-old man presenting with tarry stool was admitted to the hospital; upper GI endoscopy revealed a gastric submucosal tumor of the stomach at the posterior wall of the cardia. Partial gastrectomy was performed laparoscopically. The submucosal lesion was histopathologically diagnosed as malignant GIST. Administration of imatinib was initiated 17 months after surgery because of recurrence of GIST. The initial dose of imatinib was 400mg/day, which was later adjusted to 200mg or 300 mg/day because of adverse effects. Though imatinib was withdrawn several times due to strong side effects, the disease was well controlled for 6 years after surgery.
Assuntos
Antineoplásicos/uso terapêutico , Benzamidas/uso terapêutico , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Piperazinas/uso terapêutico , Pirimidinas/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Idoso de 80 Anos ou mais , Gastrectomia , Tumores do Estroma Gastrointestinal/cirurgia , Humanos , Mesilato de Imatinib , Masculino , Recidiva , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgiaRESUMO
A novel melanogenesis inhibitor, byelyankacin (1), was isolated from the fermentation broth of a bacterial strain. The producing organism, designated B20, was identified as a member of the genus Enterobacter based on taxonomic characteristics. 1 was obtained as a white powder from the culture medium by solvent extraction and serial chromatographic purification. The structure of 1 was determined as (E)-4-(2-isocyanovinyl)phenyl alpha-L-rhamnopyranoside on the basis of spectroscopic data. 1 potently inhibited mushroom tyrosinase and melanogenesis of B16-2D2 melanoma cells with IC50 value of 2.1 nM and 30 nM, respectively.
Assuntos
Enterobacter/metabolismo , Melaninas/biossíntese , Monossacarídeos/biossíntese , Monossacarídeos/farmacologia , Nitrilas/farmacologia , Linhagem Celular Tumoral , Meios de Cultura/química , Fermentação , Humanos , Espectroscopia de Ressonância Magnética , Melaninas/antagonistas & inibidores , Melanoma Experimental/metabolismo , Monofenol Mono-Oxigenase/antagonistas & inibidores , Espectrofotometria Infravermelho , Espectrofotometria UltravioletaRESUMO
BACKGROUND: We have previously demonstrated that therapy with orally administered L-glutamine improves nicotinamide adenosine dinucleotide (NAD) redox potential of sickle red blood cells (RBC). On further analysis of L-glutamine therapy for sickle cell anemia patients, the effect of L-glutamine on adhesion of sickle RBC to human umbilical vein endothelial cells (HUVEC) was examined. METHODS: The first part of the experiment was conducted with the blood samples of the 5 adult sickle cell anemia patients who had been on L-glutamine therapy for at least 4 weeks on a dosage of 30 grams per day compared to those of patient control group. In the second part of the experiment 6 patients with sickle cell anemia were studied longitudinally. Five of these patients were treated with oral L-glutamine 30 grams daily and one was observed without treatment as the control. t-test and paired t-test were used for determination of statistical significance in cross-sectional and longitudinal studies respectively. RESULTS: In the first study, the mean adhesion to endothelial cells with the autologous plasma incubated cells were 0.97 +/- 0.45 for the treated group and 1.91 +/- 0.53 for the nontreated group (p < 0.02). Similarly with lipopolysaccharide (LPS) incubated cells the mean adhesion to endothelial cells were 1.39 +/- 0.33 for the treated group and 2.80 +/- 0.47 for the untreated group (p < 0.001). With the longitudinal experiment, mean decrease in the adhesion to endothelial cells was 1.13 +/- 0.21 (p < 0.001) for the 5 treated patients whereas the control patient had slight increase in the adhesion to endothelial cells. CONCLUSION: In these studies, oral L-glutamine administration consistently resulted in improvement of sickle RBC adhesion to HUVEC. These data suggest positive physiological effects of L-glutamine in sickle cell disease.
RESUMO
BACKGROUND: Desferrioxamine (DFO) is an important iron chelating agent. It has also been thought of as an agent with anti-oxidant potential as it chelates ferric iron in various parts of the body. However, there is evidence suggesting that it may paradoxically affect red blood cells (RBC) by inducing intracellular oxidant stress. To further understand the mechanism of DFO's interaction with RBC, we conducted a study to determine the effect of DFO upon RBC's redox status. METHODS: We examined NAD redox potential in intact RBC (N = 5) incubated with DFO. RBC were incubated with 6 mM DFO for 2 hours. RESULTS: Significant decreases in NAD redox potential were observed after incubation of RBC with 6 mM DFO. The mean decrease was 10.01 PlusMinus; 1.98% (p < 0.0004). CONCLUSIONS: The data confirm the oxidant effect of DFO on RBC.
Assuntos
Desferroxamina/farmacologia , Eritrócitos/efeitos dos fármacos , Quelantes de Ferro/farmacologia , NAD/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Eritrócitos/metabolismo , Humanos , Oxirredução/efeitos dos fármacosRESUMO
A novel antifungal antibiotic, YM-193221, was found in the culture broth of a fungus, Pseudallescheria ellipsoidea. The structure of the antibiotic was determined through several spectroscopic experiments as 2-dimethylamino-1-(4-hydroxyphenyl)-8,10-dimethyl-6-dodecene-3-one. YM-193221 exhibited potent antifungal activity against Candida albicans and also inhibited mannan synthesis in the yeast cell wall.
Assuntos
Antifúngicos , Cetonas , Fenetilaminas , Pseudallescheria/metabolismo , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Antifúngicos/toxicidade , Candida albicans/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Fungos/efeitos dos fármacos , Células HeLa , Humanos , Cetonas/química , Cetonas/isolamento & purificação , Cetonas/farmacologia , Cetonas/toxicidade , Mananas/biossíntese , Testes de Sensibilidade Microbiana , Fenetilaminas/química , Fenetilaminas/isolamento & purificação , Fenetilaminas/farmacologia , Fenetilaminas/toxicidade , Relação Estrutura-AtividadeRESUMO
We present a case of inner head dislocation 11 years after the replacement of a bipolar prosthesis with a self-centering system. An 84-year-old woman with osteoarthritis of the left hip underwent a replacement of the Bateman UPF-II bipolar prosthesis in 1987. She fell off a chair on April 19 1998, and felt a sudden sharp pain in the left hip. Roentgenograms revealed that the inner head was dislocated from the outer head. Moreover, on June 19, when she stood up from the floor, the dislocation recurred. On July 23, a revision surgery was carried out. When the outer head was removed from the acetabulum, the bearing insert was markedly worn by the impingement of the femoral stem neck. Because there was no evidence of loosening of the femoral stem, a cemented replacement of the acetabular component was performed. At a 2-year follow-up, she had mild hip pain, but had returned fully to daily living. Our review of current published studies reveals that most inner head dislocations occurred in osteoarthritic patients. Thus, the occurrence of dislocations may be more dependent on patient selection than on failure of the bipolar prosthesis itself.
Assuntos
Prótese de Quadril , Falha de Prótese , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Osteoartrite/cirurgia , Desenho de PróteseRESUMO
We present two rare cases of volar and dorsal fractures of the middle phalanx at the proximal interphalangeal joint (PIPJ). The first case was a 16-year-old girl. She hurt her middle finger while playing basketball. A lateral radiograph revealed volar and dorsal fractures of the middle phalanx. She underwent external immobilization of the PIPJ in 30 degrees of flexion with a splint for 3 weeks. The fractures healed 7 weeks after the injury with neither tenderness nor limitation of range of motion. The second case was a 16-year-old boy. He injured his index finger while playing basketball, and underwent immobilization of the PIPJ for 3 weeks. At 10 weeks after the injury, the dorsal fracture was almost healed, but the displacement of the volar fragment had worsened. At a 3-year follow-up, the dorsal fragment was healed, but the volar fragment remained in a site of nonunion. However, there was neither residual deformity nor restriction of movement.
Assuntos
Basquetebol/lesões , Traumatismos dos Dedos/diagnóstico por imagem , Fraturas Ósseas/diagnóstico por imagem , Adolescente , Feminino , Humanos , Masculino , RadiografiaRESUMO
Aseptically prepared cold drinks based on tea have become popular worldwide. Contamination of these drinks with harmful microbes is a potential health problem because such drinks are kept free from preservatives to maximize aroma and flavour. Heat-tolerant conidia and ascospores of fungi can survive pasteurization, and need to be detected as quickly as possible. We were able to rapidly and accurately detect low numbers of conidia and ascospores in tea-based drinks using fluorescent staining followed by an automated counting system. Conidia or ascospores were inoculated into green tea and oolong tea, and samples were immediately filtered through nitrocellulose membranes (pore size: 0.8 µm) to concentrate fungal propagules. These were transferred onto potato dextrose agar and incubated for 23 h at 28 °C. Fungi germinating on the membranes were fluorescently stained for 30 min. The stained mycelia were counted selectively within 90s using an automated counting system (MGS-10LD; Chuo Electric Works, Osaka, Japan). Very low numbers (1 CFU/100ml) of conidia or ascospores could be rapidly counted, in contrast to traditional labour intensive techniques. All tested mould strains were detected within 24h while conventional plate counting required 72 h for colony enumeration. Counts of slow-growing fungi (Cladosporium cladosporioides) obtained by automated counting and by conventional plate counting were close (r(2) = 0.986). Our combination of methods enables counting of both fast- and slow-growing fungi, and should be useful for microbiological quality control of tea-based and also other drinks.
Assuntos
Contagem de Colônia Microbiana/métodos , Microbiologia de Alimentos/métodos , Fungos/isolamento & purificação , Esporos Fúngicos/isolamento & purificação , Chá/microbiologia , Automação Laboratorial , Filtração , Contaminação de AlimentosRESUMO
Stable alginate microcapsules in dried form containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (HA) were prepared by coating of fresh alginate microcapsules with chitosan or polyethyleneimine (PEI). The thickness of coatings was estimated by electron probe microanalysis (EPMA), along with electron microscopy (SEM), as well as comparison of uptake percentage of coated and uncoated hollow capsules. Characterization of microcapsules was carried out by Ag(+) uptake experiments, destructive chemical analyses and thermogravimetric methods (TG and DTA). Chemical stability tests in HNO(3) and NaNO(3) media indicated that the coating with 4-double layer chitosan or mono-layer PEI led to an appreciable enhancement of impermeability in the range of pH > 1 or [Na(+)] < 1 M (mol dm(-3)). Unfortunately, multiple coating causes some extractant losses due to effect of physical stress during the coating; however, PEI-coated microcapsules nearly completely hold their extractant content. Stable extractive microcapsules have an appreciable potential for the selective removal of heavy metal ions.
Assuntos
Alginatos/química , Quitosana/química , Metais Pesados/isolamento & purificação , Polietilenoimina/química , Cápsulas , Materiais Revestidos Biocompatíveis/química , Ácido Glucurônico/química , Íons Pesados , Ácidos Hexurônicos/química , Cinética , Microscopia Eletrônica de VarreduraRESUMO
Pulmonary complications are an important cause of the mortality associated with liver transplantation. The efficacy of noninvasive ventilation (NIV) in pediatric patients following transplantation is unknown. The purpose of this retrospective study is to investigate the effects of NIV for pediatric patients undergoing liver transplantation. Of 102 pediatric patients who underwent liver transplantation, 15 patients (aged 73 months; range 2.5-179) were supported by NIV because of atelectasis, hypercapnia, hypoxemia, pneumonia, massive effusion, or postextubation ventilatory support. Of 15 patients, 5 were under the age of 1 year (range 2.5-12 months). Of the 15 patients, 7 had required multiple intubations before NIV treatment because of pulmonary complications. NIV treatment was administered to 6 patients because of hypercapnia. Partial pressure of arterial carbon dioxide (PaCO(2)) levels improved from 56.9 (95% confidence interval [CI]: 48.4-65.4) to 41.5 (95% CI: 36.8-46.2) mmHg (P = .028) within 2 days. NIV treatment was very effective for patients with atelectasis with and without other pulmonary complications. Mean inspiratory positive pressure (IPAP) was 7.2 (95% CI: 6.0-8.3) cm H(2)O and expiratory positive pressure (EPAP) was 3.5 (95% CI: 3.2-3.9) cm of H(2)O. Mean duration of NIV was 18.5 (95% CI: 8.6-28.4) days. IPAP and EPAP levels were closely and significantly correlated with height (IPAP: r = .65, P = .016; EPAP: r = .77, P = .004). A total of 13 patients recovered and 2 patients died. However, no patient died of respiratory complications. In conclusion, NIV is effective in pediatric patients undergoing liver transplantation with subsequent pulmonary complications. The IPAP and EPAP levels may be predicted by the height of the patient.