Transepithelial transport of 6-O-caffeoylsophorose across Caco-2 cell monolayers

The aim of this study was to clarify the transport behaviour and mechanism of caffeic acid analogue bearing a sugar-moiety, 6-O-caffeoylsophorose (CS), in Caco-2 cells. The absorption of CS was investigated by its transport across Caco-2 cell monolayers using a high-performance liquid chromatography-time-of-flight-mass spectrometry (LC–TOF-MS). The permeation of CS was concentration-dependent and reached the plateau at >6 mM. The apparent permeability (P_app) of CS in the apical-to-basolateral direction was 5.4 × 10⁻⁷ cm/s, while in the reversed direction the P_app value was significantly reduced (1.9 × 10⁻⁷ cm/s). CS transport was competitively inhibited by phloretin, an inhibitor of monocarboxylic acid transporter (MCT). Benzoic acid, an MCT substrate, also reduced CS transport. A less significant change of CS transport was observed across Caco-2 cell monolayers pretreated with quercetin, a suppressor of tight-junction. These findings strongly indicate that CS, a caffeic acid analogue bearing sophorose moiety, can be transported across Caco-2 cell monolayers via the MCT pathway.     

Electrochemical Direct Fluorination of Lactams

The electrochemical fluorination of a variety of N-protected lactams was carried out and Et₃N–5HF was found to be superior to Et₃N–3HF as the electrolyte. When 5- and 6-membered N-acetyl or ethoxycarbonyl lactams were used as substrates, the fluorination reaction selectively took place at the α-position of the lactam nitrogen and the corresponding monofluoro products could be obtained in good yields.     

A new lead alloy current-collector manufactured by a powder rolling process and its corrosion behavior under lead-acid battery conditions

A new powder rolling process for manufacturing current-collector sheets for lead-acid batteries has been developed. Gas-atomized lead–tin and lead–tin–calcium alloy powders obtained by a rapid solidification process in air were employed as raw materials for the powder rolling process. The corrosion behavior of powder-rolled lead–tin alloys with various compositions of tin has been investigated. A dipping corrosion test of square plain sheets of the alloys was performed in H₂SO₄ at 75 °C. The test was repeated up to 20 cycles with each cycle consisting of a controlled 10 mA cm⁻² oxidation current for 6 h and a rest under open circuit voltage for 6 h. The extent of corrosion–elongation and the appearance of the corroded surface of the tested specimens were the main observations. The corrosion–elongation of the corroded sheet of a powder-rolled lead alloy containing 1.5 wt% tin with ca. 200 μm initial thickness was less than 5%, whereas that of the corroded sheet of the cast-rolled lead alloy containing 1.5 wt% tin with the same initial thickness was 25–30% under the same corrosion test conditions. The corroded powder-rolled sheet of the 1.5 wt% tin lead alloy has uniform corrosion, but the cast-rolled sheet of lead alloy containing 1.5 wt% tin was much distorted and was perforated by the corrosion. Intergranular corrosion of the powder-rolled lead–tin alloys was much suppressed as compared with that of the cast-rolled lead–tin alloys.     

Localization of D-��-Aspartyl Residue-Containing Proteins in Various Tissues

Prior to the emergence of life, it is believed that only l-amino acids were selected for formation of protein and that d-amino acids were eliminated on the primitive Earth. Whilst homochirality is essential for life, the occurrence of proteins containing d-β-aspartyl (Asp) residues in various tissues from elderly subjects has been reported recently. Here, we demonstrate the presence of a d-β-Asp-containing protein in the cardiac muscle of heart, blood vessels of the lung, chief cells of the stomach, longitudinal and circular muscle of the stomach, small intestine and large intestine. Since the d-β-Asp residue occurs through a succinimide intermediate, this isomer may potentially be generated in proteins more easily than initially thought. Formation of the d-β-Asp residue in proteins may be related to stress.     

A Phenylfurocoumarin Derivative Reverses ABCG2-Mediated Multidrug Resistance In Vitro and In Vivo

The ATP-binding cassette subfamily G member 2 (ABCG2) transporter is involved in the development of multidrug resistance in cancer patients. Many inhibitors of ABCG2 have been reported to enhance the chemosensitivity of cancer cells. However, none of these inhibitors are being used clinically. The aim of this study was to identify novel ABCG2 inhibitors by high-throughput screening of a chemical library. Among the 5812 compounds in the library, 23 compounds were selected in the first screening, using a fluorescent plate reader-based pheophorbide a (PhA) efflux assay. Thereafter, to validate these compounds, a flow cytometry-based PhA efflux assay was performed and 16 compounds were identified as potential inhibitors. A cytotoxic assay was then performed to assess the effect these 16 compounds had on ABCG2-mediated chemosensitivity. We found that the phenylfurocoumarin derivative (R)-9-(3,4-dimethoxyphenyl)-4-((3,3-dimethyloxiran-2-yl)methoxy)-7H-furo [3,2-g]chromen-7-one (PFC) significantly decreased the IC₅₀ of SN-38 in HCT-116/BCRP colon cancer cells. In addition, PFC stimulated ABCG2-mediated ATP hydrolysis, suggesting that this compound interacts with the substrate-binding site of ABCG2. Furthermore, PFC reversed the resistance to irinotecan without causing toxicity in the ABCG2-overexpressing HCT-116/BCRP cell xenograft mouse model. In conclusion, PFC is a novel inhibitor of ABCG2 and has promise as a therapeutic to overcome ABCG2-mediated MDR, to improve the efficiency of cancer chemotherapy.     

Effects of Surface-Deacetylated Chitin Nanofibers in an Experimental Model of Hypercholesterolemia

This study evaluated the effects of oral administration of surface-deacetylated chitin nanofibers (SDACNFs) on hypercholesterolemia using an experimental model. All rats were fed a high cholesterol diet with 1% w/w cholesterol and 0.5% w/w cholic acid for 28 days. Rats were divided equally into four groups: the control group was administered 0.05% acetic acid dissolved in tap water, and the SDACNF, chitosan (CS), and cellulose nanofiber (CLNF) groups were administered 0.1% CNF, CS, or CLNF dissolved in the tap water, respectively, during the experimental period. Changes in body weight, intake of food and water, and organ weight were measured. Serum blood chemistry and histopathological examination of the liver were performed. Administration of SDACNF did not affect body weight change, food and water intake, or organ weights. Administration of SDACNF and CS decreased the diet-induced increase in serum total cholesterol, chylomicron, very-low-density lipoprotein, and phospholipid levels on day 14. Moreover, oral administration of SDACNFs suppressed the increase of alanine transaminase levels on day 29 and suppressed vacuolar degeneration and accumulation of lipid droplets in liver tissue. These data indicate that SDACNF has potential as a functional food for patients with hypercholesterolemia.     

Formation of Expandable Mica from Talc Using the Intercalation Procedure

To investigate the transformation process from talc to expandable micas, mixtures of talc and Na₂SiF₆ were heated from 600° to 900°C and air-quenched at 50°C intervals. The air-quenched product at 800°C mainly consisted of expandable micas with a basal spacing of 1.25 nm, nonexpandable materials with a basal spacing of 0.96 nm, and a small amount of talc used as the starting material. A lattice fringe image by HRTEM of the product shows that the layer spacing at the edges surfaces is about 1.2 nm, but the layer spacing inside of the particles is close to that of talc. Such a nanostructure indicates a topotactic reaction from talc to expandable micas and confirms that Na⁺ ions intercalate into the structure from the edge to the core.     

Optical compensation for hologram distortion using wavefront interpolation in angle-multiplexed holograms

Distortion of the hologram may occur when the photopolymer material used in the medium shrinks or expands. We analyzed interference fringe distortion for plane waves and a reference beam with an angular gap between recording and reproducing for the purpose of compensating for the distortion. We found that the wavefronts that could compensate for the distortion could approximately be obtained by linear interpolation of such angle-multiplexed holograms. We recorded 80 data pages with the angle-multiplexing method and obtained an optimized wavefront to compensate for hologram distortion on the first, fortieth, and eightieth data pages using adaptive optics with genetic algorithms and linear interpolated wavefronts at the other data pages. The calculation time for 80 wavefronts to compensate for distortion fell to 3/80th of that of having to calculate optimizations for all pages. The bit error rates were lower than 1.0?×?10^?2 on all data pages reproduced using these wavefronts.     

Low-temperature deposition of ZnO thin films on PET and glass substrates by DC-sputtering technique

The structural, optical and electrical properties of ZnO thin films (260 - 490 nm thick) deposited by direct-current sputtering technique, at a relatively low-substrate temperature (363 K), onto polyethylene terephthalate and glass substrates have been investigated. X-ray diffraction patterns confirm the proper phase formation of the material. Optical transmittance data show high transparency (80% to more than 98%) of the films in the visible portion of solar radiation. Slight variation in the transparency of the films is observed with a variation in the deposition time. Electrical characterizations show the room-temperature conductivity of the films deposited onto polyethylene terephthalate substrates for 4 and 5 h around 0.05 and 0.25 S cm^− 1, respectively. On the other hand, for the films deposited on glass substrates, these values are 8.5 and 9.6 S cm^− 1 for similar variation in the deposition time. Room-temperature conductivity of the ZnO films deposited on glass substrates is at least two orders of magnitude higher than that of ZnO films deposited onto polyethylene terephthalate substrates under identical conditions. Hall-measurements show the maximum carrier concentration of the films on PET and glass substrate around 2.8 × 10¹⁶ and 3.1 × 10²⁰ cm^− 3, respectively. This report will provide newer applications of ZnO thin films in flexible display technology.