149 research outputs found
ZnO nanorods prepared via ablation of Zn with millisecond laser in liquid media
ZnO nanomaterials with controlled size, shape and surface chemistry are required for applications in diverse areas, such as optoelectronics, photocatalysis, biomedicine and so on. Here, we report on ZnO nanostructures with rod-like and spherical shapes prepared via laser ablation in liquid using a laser with millisecond-long pulses. By changing laser parameters (such as pulse width and peak power), the size or aspect ratio of such nanostructures could be tuned. The surface chemistry and defects of the products were also strongly affected by applied laser conditions. The preparation of different structures is explained by the intense heating of liquid media caused by millisecond-long pulses and secondary irradiation of already-formed nanostructures
Defects in ZnO nanoparticles laser-ablated in water-ethanol mixtures at different pressures
The effect of liquid medium and its pressure on the photoluminescence of ZnO nanoparticles prepared via laser ablation of Zn targets in various water-ethanol mixtures is studied. As the ethanol content increases, the photoluminescence of the product changes, while metallic zinc is observed to emerge in nanomaterials prepared in ethanol-rich environments. The applied pressure had a less profound effect, mainly affecting materials produced in water or water-ethanol, and much less those generated in pressurized ethanol. Tuning the reactivity of the liquid and pressurizing it during laser ablation is demonstrated to be promising for tailoring the emission properties of the product
Crystal structures of racemic and enantiomeric 5-isopropyl-5-methylhydantoin
Crystal structures of racemic and enantiomeric 5-isopropyl-5-methylhydantoin (IPrMH) have been determined by single crystal X-ray diffraction. Melting temperatures and solid state infrared spectra are also measured. Racemic IPrMH has a lower melting temperature than the pure enantiomer by 25 °C. The infrared spectrum of racemic IPrMH is identical with that of the pure enantiomer. Nevertheless, the racemic IPrMH doesn’t crystallize as a conglomerate but as a racemic compound. The racemic and the enantiomeric crystals are very similar to each other in molecular geometries and intermolecular interactions. In the both cases, the molecules are connected via N−H···O hydrogen bonds to form R22(8) rings, and these rings are linked into infinite one-dimensional tapes. In the racemic crystal, a single tape is composed of single enantiomer and itself is homochiral
Synthesis and crystal structure of (S)-5-isopropyl-5-methyl-2-thiohydantoin
(S)-5-Isopropyl-5-methyl-2-thiohydantoin was synthesized by one-pot reaction of α-methyl-L-valine and thiourea in the absence of solvent. The crystal structure of this compound has been determined from single crystal X-ray diffraction data. This is the first report on the crystal structure of a homochiral 5-substituted 2-thiohydantoin with the unsubstituted NH groups. This compound, C7H12N2OS crystallizes in the chiral orthorhombic space group P212121 with four molecules in the unit cell. The unit cell parameters are: a = 8.2798(12) Å, b = 8.6024(13) Å, c = 12.826(2) Å and V = 913.6(2) Å3. In the crystals, the thioamide and amide N-H of one molecule are hydrogen-bonded to the thioamide C=S group of neighboring molecules to form rings with the R22(8) graph-set motif, and these rings are linked into infinite one-dimensional tapes
Conditioned medium from stem cells derived from human exfoliated deciduous teeth ameliorates NASH via the Gut-Liver axis
Non-alcoholic steatohepatitis (NASH) occurrence has been increasing and is becoming a major cause of liver cirrhosis and liver cancer. However, effective treatments for NASH are still lacking. We examined the benefits of serum-free conditioned medium from stem cells derived from human exfoliated deciduous teeth (SHED-CM) on a murine non-alcoholic steatohepatitis (NASH) model induced by a combination of Western diet (WD) and repeated administration of low doses of carbon tetrachloride intraperitoneally, focusing on the gut-liver axis. We showed that repeated intravenous administration of SHED-CM significantly ameliorated histological liver fibrosis and inflammation in a murine NASH model. SHED-CM inhibited parenchymal cell apoptosis and reduced the activation of inflammatory macrophages. Gene expression of pro-inflammatory and pro-fibrotic mediators (such as Tnf-α, Tgf-β, and Ccl-2) in the liver was reduced in mice treated with SHED-CM. Furthermore, SHED-CM protected intestinal tight junctions and maintained intestinal barrier function, while suppressing gene expression of the receptor for endotoxin, Toll-like receptor 4, in the liver. SHED-CM promoted the recovery of Caco-2 monolayer dysfunction induced by IFN-γ and TNF-α in vitro. Our findings suggest that SHED-CM may inhibit NASH fibrosis via the gut-liver axis, in addition to its protective effect on hepatocytes and the induction of macrophages with unique anti-inflammatory phenotypes
Persimmon Tannin Gel: Formation by Autoxidation and Caffeine Adsorption Properties
金沢大学理工研究域物質化学系Water-insoluble gel was prepared from persimmon tannin (PT) solution by the autoxidation process. The gelation reaction proceeded by applying oxygen gas and natural light to the aqueous PT solution, without using harmful reagents or catalysts. Adsorption behavior of the PT gel was assessed using caffeine. Batch adsorption studies were conducted to evaluate the influence of experimental parameters such as contact time, initial concentration of adsorbates, adsorbent dose and temperature. The equilibrium data were analyzed using Freundlich and Langmuir isotherm models. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy changes were also calculated, showing that caffeine adsorption on the PT gel is an exothermic process and feasible at lower temperatures. The present results suggest that the PT gel can be used as an effective adsorbent for removing caffeine from solutions.出版者照会後に全文公
Augmentation of Positive Valence System–Focused Cognitive Behavioral Therapy by Inaudible High-Frequency Sounds for Anhedonia : A Trial Protocol for a Pilot Study
Importance Recent conceptualizations in Research Domain Criteria have indicated that anhedonia, 1 of 2 core symptoms of depression, which can be treatment resistant, is associated with deficits in the positive valence system, and inaudible high-frequency sound therapy has been shown to enhance reward-related brain circuitry. Hence, cognitive behavioral therapy focusing on the positive valence system enhanced with sound therapy could have a synergistic effect on anhedonia.Objective To test the augmentation effect of inaudible high-frequency sounds on the efficacy of positive valence system–focused cognitive behavioral therapy to treat anhedonia.Design, Setting, and Participants In this individual-level allocation, exploratory, single-center randomized superiority pilot trial, patients, therapists, and evaluators will be masked to intervention or placebo assignment. The trial will take place at a national psychiatric referral hospital in Tokyo, Japan, among 44 adult patients with clinically significant anhedonia and moderate to severe depression. Outcomes will be analyzed following the intent-to-treat principle using a repeated-measures mixed model.Intervention The intervention group will participate in 8 weekly sessions of positive valence system–focused cognitive behavioral therapy with in-session exposure to an inaudible high-frequency sound; the comparison group will undergo cognitive behavioral therapy with in-session exposure to a placebo sound.Main Outcomes and Measures The primary outcome is anhedonia assessed using the self-reported Snaith-Hamilton Pleasure Scale. The secondary outcome is anhedonia assessed using the clinician-administered version of the Snaith-Hamilton Pleasure Scale.Discussion Recruitment for this study began in May 2018, and the projected date of final allocation is January 2020. A total of 21 eligible patients were registered for participation as of May 30, 2019. To date, treatments for depression do not guarantee clinically successful outcomes. This pilot trial will provide preliminary evidence of the augmentation effect of high-frequency inaudible sounds on cognitive behavioral therapy for anhedonia. Overall, exposure to an inaudible high-frequency sounds does not require attentional or cognitive effort from either patients or therapists; therefore, results from a future confirmative trial could indicate that cognitive behavioral therapy can be augmented in an effortless manner
A new experimental system for irradiating tumors in mice using a linear accelerator under specific pathogen-free conditions.
We developed a reliable system for the irradiation of xenografted tumors in mice which allows for accurate local irradiation under specific pathogen-free conditions. The system presented here consists of acrylic supports for mice and an acrylic box connected to a pump through 0.22 microns pore-sized filters. Mice with xenotransplanted tumors growing on their right hind legs were set on the supports and put into the box in a laminar flow hood. The tumors of 7 mice were irradiated simultaneously with X-rays of 6 and 10 MV generated by a linear accelerator at a dose rate of 3.1-4.7 Gy/min. The air was ventilated through filters during irradiation in the closed box. Microorganism tests confirmed that no bacteria entered or left the box. One of the significant characteristics of this setup is that it allows for irradiation under conditions of acute hypoxia, which is obtained using an integrated tourniquet. The dose variation among 7 tumors was less than 1%. The rest of the mouse's body was shielded effectively by a half-field technique and a lead block. As a result, the whole body dose for the mice was 0-4% of the total dose absorbed by the tumor. Due to the high dose rate and the ability to irradiate 7 mice simultaneously under specific pathogen-free conditions, this new system can be considered a time-saving and valuable tool for radiation oncology research.</p
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