Kyanamide,a new Ahp-containing depsipeptide from marine cyanobacterium Caldora penicillata

Kyanamide (1), a new depsipeptide containing 3-amino-6-hydroxy-2-piperidone moiety, was isolated from the Caldora penicillata marine cyanobacterium collected in Okinawa. Its structure was determined by spectroscopic analysis and Marfey's analysis of acid hydrolysate. Kyanamide exhibited moderate cytotoxicity against HeLa S3 cells. 1 also exhibited potent protease inhibitory activity against elastase and chymotrypsin with IC₅₀ values of 0.13 nM and 1.1 μM.     

Intrauterine devices and uterine peristalsis: evaluation with MRI

Intrauterine devices (IUDs) have been viewed as an effective form of contraception. However, the mechanism by which IUDs disturb fertility remains controversial. This study aimed to evaluate the effects of IUDs on uterine contractility using cine MR. Eleven healthy female volunteers of reproductive age bearing IUDs and 12 women not bearing IUDs were evaluated during the periovulatory phase. MR images were obtained with a 1.5-T magnet, acquiring 60 serial images every 3 s via half-Fourier acquisition single-shot turbo spin echo to be displayed on cine mode. Assessments were based on (a) the presence of peristaltic waves, (b) the frequency and direction of peristaltic waves and (c) the extent of peristaltic waves. Static images were evaluated for thickness of the junctional zone (JZ) and myometrium. A fundo-cervical (FC)-directed peristaltic wave was identified in 4 of 11 IUD-bearing subjects and in only 1 of 12 subjects from the control group. FC waves extended through more than half of the thickness of the myometrium. Peristaltic frequency in IUD users (5.0/3 min) was less than that of the control group (6.5/3 min). The JZ and myometrium were significantly thicker in IUD users. FC-directed waves were more often observed in IUD-bearing subjects, which might explain the inhibition of active sperm transport.     

Mapping of the cationic starch adsorbed on pulp fibers by ToF-SIMS

Cationic starch (CS) is routinely used in the papermaking process to improve the dry strength or printability of paper. The effectiveness depends on the distribution of the starch on the pulp fiber, and in this study, time-of-flight secondary ion mass spectrometry was used to investigate this distribution. The characteristic peak at 58m/z was applied to map the CS. Based on the imaging analysis of the handsheets with the CS as an internal additive, the distribution of CS became more uniform with decreasing freeness. The amount of adsorbed CS increased with increasing fiber length and was lower on vessels than on other fibers. These results were related to fibrillation. From the analysis of handsheets with CS as an external additive, the penetration depth of the starch into base paper increased with decreases in the sizing degree of the base paper.     

STM/STS study on nondispersive checkerboard superstructure in superconducting Bi2212 and La-Bi2201

We performed STM/STS measurements on superconducting Bi2212 and La-Bi2201 in order to study the nondispersive two-dimensional (2D) electronic superstructure, namely the so-called checkerboard. The nondispersive checkerboard clearly appears within the pairing gap in both systems, although the period is different between Bi2212 (∼4a×4a) and La-Bi2201 (∼5a×5a). We point out that the nondispersive checkerboard originates in hole-pairs and/or quasiparticles around the antinodes of the d-wave gap, and interrelates with the spatially inhomogeneous pairing gap.     

Utilization of Sodium Nitroprusside as an Intestinal Permeation Enhancer for Lipophilic Drug Absorption Improvement in the Rat Proximal Intestine

As advanced synthetic technology has enabled drug candidate development with complex structure, resulting in low solubility and membrane permeability, the strategies to improve poorly absorbed drug bioavailability have attracted the attention of pharmaceutical companies. It has been demonstrated that nitric oxide (NO), a vital signaling molecule that plays an important role in various physiological systems, affects intestinal drug absorption. However, NO and its oxidants are directly toxic to the gastrointestinal tract, thereby limiting their potential clinical application as absorption enhancers. In this study, we show that sodium nitroprusside (SNP), an FDA-approved vasodilator, enhances the intestinal absorption of lipophilic drugs in the proximal parts of the small intestine in rats. The SNP pretreatment of the rat gastrointestinal sacs significantly increased griseofulvin and flurbiprofen permeation in the duodenum and jejunum but not in the ileum and colon. These SNP-related enhancement effects were attenuated by the co-pretreatment with dithiothreitol or c-PTIO, an NO scavenger. The permeation-enhancing effects were not observed in the case of antipyrine, theophylline, and propranolol in the duodenum and jejunum. Furthermore, the SNP treatment significantly increased acidic glycoprotein release from the mucosal layers specifically in the duodenum and jejunum but not in the ileum and colon. These results suggest that SNP increases lipophilic drug membrane permeability specifically in the proximal region of the small intestine through disruption of the mucosal layer.     

Variations of natural 15N abundances in the tissues and digesta of domestic animals

The natural abundance of 15N (expressed as delta 15N per mil relative to air N2) in the tissues and the change of 15N abundance during the digestion processess in cattle, pig, and goat were investigated. The 15N abundances of cattle tissues differed by about 3.5% with high values in heart, urinary bladder and diaphragm. The ages of cattle did not affect on the 15N abundances of liver and kidney in cattle. The 15N abundances of urine were lower, and those of feces were a little higher than the values of diets in cattle and pigs. The delta 15N values of milk and blood were higher than the value of diets. Two peaks of 15N abundances at forestomach and caecum were observed during the digestion processes of diet in goats. The mechanisms of the variation of 15N abundances in animal bodies were briefly discussed.     

Photoelastic Analysis with a Single Tricolor Image

A new approach to simultaneous measurement of isochromatics and isoclinics from a single image using a tricolor light, called as the tricolor photoelastic technique, is proposed in order to enable and facilitate the analysis of time varying phenomena. Not only an apparatus of experiment but the whole analysis system and procedure are developed. Using a color digital camera and a tricolor light source under linear polarization, fringe order and the principal direction of birefringence are obtained from a piece of color image data by a single shot using the method proposed. It is emphasized that this method can be applicable to time varying phenomena in which good repeatability and reproducibility of experiments are not expected, since multiple exposures are not necessary for sufficient data acquisition in the completion of stress analysis.     

Cyclotrisilenylium ion: the persilaaromatic compound

The highly crowded 3,3-bis(di-tert-butylmethylsilyl)-1,2-bis(tri-tert-butylsilyl)cyclotrisilene (3) was newly designed as a precursor of the cyclotrisilenylium ion and prepared by the reaction of 2 equiv of dilithiosilane (tBu2MeSi)2SiLi2 (1) with 2,2,3,3-tetrabromo-1,1,1,4,4,4-hexa-tert-butyltetrasilane. The reaction of 3 with triphenylmethylium tetraarylborate in toluene produced (di-tert-butylmethylsilyl)bis(tri-tert-butylsilyl)cyclotrisilenylium ion (4+), which was isolated in the form of the tetraarylborate salt as extremely air- and moisture-sensitive yellow crystals, representing the first isolable silicon congener of the cyclopropenylium ion. The molecular structure of 4+.TSFPB- (TSFPB- = tetrakis[4-(tert-butyldimethylsilyl)-2,3,5,6-tetrafluorophenyl]borate) was established by X-ray crystallographic analysis, showing that the three-membered ring constitutes an almost equilateral triangle with average Si-Si bond lengths of 2.216(3) A. The X-ray crystal structure and spectral data show that 4+ is not only a free silyl cation but also a 2pi electron aromatic species with delocalization of the positive charge over the three-membered skeleton.     

Preparation and properties of polyarylates and copolyarylates from phenylindanedicarbonyl chloride and bisphenols

A series of polyarylates having inherent viscosities of 0.4–1.1 dL/g was prepared by the two phase polycondensation of 1,1,3-trimethyl-3-(4-chloroformylphenyl)indanecarbonyl chloride with various bisphenols in an organic solvent–aqueous alkaline solution system in the presence of a phase transfer catalyst. Similarly, copolyarylates of high molecular weights were prepared from a mixture of the phenylindanedicarbonyl chloride, terephthaloyl chloride, and 2,2-bis(4-hydroxy-phenyl)propane. All the polyarylates were characterized by their amorphous nature and high solubility in organic solvents. They gave transparent and tough films by the solution casting. The films had tensile strength of 33–46 MPa, elongation at break of 3–16%, and tensile modulus of 1.2–1.6 GPa. These polyarylates had glass transition temperatures in the range of 205–310°C, and began to decompose at ca. 350°C in air.