Epitaxial growth of isotactic polypropylene on oriented polyethylene from solution

Oriented polyethylene (PE) films with surfaces bounded by the (100) plane were prepared. On the film surfaces, isotactic polypropylene (iPP) was crystallized epitaxially from solution as quadrits with their sides parallel and perpendicular to the polyethylene chain axis. In the through wide-angle x-ray diffraction pattern (taken with incident x-rays normal to the polyethylene film surface), the 111 iPP reflections was observed on the meridian (Parallel to the polyethylene chain axis). In the edge patterns (taken with x-rays incident on the edge of the polyethylene film), 040 and 060 reflections were observed on the equator. From the diffraction patterns, the following lattice coincidence was observed between polyethylene and isotactic polypropylene: (010)iPP//(100) PE, [101]iPP//[001] PE. The Small-angle x-ray scattering patterns showed that edge-on isotactic polypropylene lamellae 9 nm thick were arranged with their long axes inclined at an angle of 40° from the polyethylene axis. Molecular chains were oriented within the lamellae normal to the surfaces.     

Environment-induced morphological changes of polyethylene lamellae during crystallization in solution

Polyethylene (PE) lamellar crystals were grown by two dual-staged crystallization methods: (1) Fractionated PE was first crystallized from n-octane by the self-seeding method, the solvent of the resulting suspension of crystals was exchanged for p-xylene, and thereafter, the suspension was mixed with a solution in p-xylene at various temperatures so that PE grew from p-xylene onto the lamellae pregrown from n-octane, and (2) according to the similar procedure, PE lamellae were first grown from p-xylene and subsequently, PE was deposited from n-octane onto the lamellae pre-grown from p-xylene. In the crystallization procedure (1), triangular lamellae with the 〈010〉 chain folding developed randomly on the {100} lateral surfaces of truncated parent lamellae so that the surfaces were serrated, and otherwise, thin daughter lamellae bordered the parent lamellae along the {110} surfaces, retaining the flat growth fronts with the 〈110〉 folding. In the procedure (2), the {100} sectors with the 〈010〉 folding developed at the apexes of the long diagonal of lozengeshaped parent lamellae, and consequently, their morphology was transfigured into a truncated crystal. These morphological transformations are discussed on the basis of the change in the interfacial free energy between the parent crystal and the surrounding phase due to the substitution of solvent. © 1994 John Wiley & Sons, Inc.     

Steric acceleration of reductive desulfonation of 1,8-naphthalenedisulfonate by an NADH model compound

1,8-Naphthalenedisulfonate was reductively desulfonated by N-benzyl-1,4-dihydronicotinamide, whereas no desulfonation was observed for the 1,6-isomer. The high reactivity of the 1,8-isomer is attributed to the steric-strain that enforces the shift of the initial state with the sp² -carbon close to the transition state with the sp³ - carbon.     

A dynamical study of the melting behavior of polypivalolactone single crystals by the X-ray diffraction method

Wide-angle and small-angle X-ray diffraction patterns of polypivalolactone single crystals were recorded as a function of temperature while heating at a constant rate. Long periods were found to increase abruptly at a certain temperature, while the degree of crystallinity decreased up to that temperature and then recovered on further heating, to an extent depending on the rate of heating. Multiple endotherms were observed in DSC measurements. The temperature at which the first endotherm peak was observed corresponded exactly to the temperature of the long period jump mentioned above. From these data, it is concluded that the original lamellar crystals melt at each peak temperature in the DSC thermogram and new lamellae are produced by subsequent crystallization. Multiple endotherms in the DSC thermogram are thus considered to represent repeated melt-recrystallization processes.     

A facile synthesis of p- and m-(amidinomethyl)phenyl esters derived from amino acid and tryptic hydrolysis of these synthetic inverse substrates

A facile synthetic method for p- and m-(amidinomethyl)phenyl esters derived from a variety of amino acids is presented. We analyzed the kinetic behavior of trypsin towards these synthetic esters, which are inverse substrates. The substituent (meta- and para-isomers) and isosteric effects of (amidinomethyl)phenyl esters are discussed.     

Synthesis of the EF-ring of ciguatoxin 3C based on the [2,3]-Wittig rearrangement and ring-closing olefin metathesis

The EF-ring segment of ciguatoxin 3C, a causative toxin of ciguatera fish poisoning, was synthesized in three major steps: 1,4-addition for the C20O-C27 bond connection, chirality transferring anti selective [2,3]-Wittig rearrangement for the construction of the anti-2-hydroxyalkyl ether part, and ring-closing olefin metathesis for the F-ring formation.     

Multimodal evaluation of an interphotoreceptor retinoid-binding protein-induced mouse model of experimental autoimmune uveitis

We aimed to characterize the vascular phenotypes of an experimental autoimmune retinal uveitis (EAU) model induced by interphotoreceptor retinoid-binding protein (IRBP) using multimodal imaging techniques. We systemically administered IRBP or vehicle to adult C57BL/6 mice. Fundus photography, optical coherence tomography (OCT), in vivo live confocal imaging using different tracers, OCT angiography (OCTA), and electroretinography (ERG) were performed after IRBP immunization. Hematoxylin and eosin and immunofluorescence staining were performed to characterize the immune response and vascular permeability. Mice with EAU exhibited perivascular inflammation, vitritis, and superficial retinal inflammation on fundus photography and OCT. H&E revealed immune cell infiltration in the perivascular area of the retina and choroid accompanied by a significant degree of perivasculitis that subsequently damaged photoreceptors 3 weeks postimmunization. Immunofluorescence staining showed subsequent transcytosis induction after local microglial activation followed by neutrophil recruitment in the perivascular area. Transcytosis in the superficial and deep vascular areas was improved by immune cell suppression. Intravital in vivo confocal imaging showed signs of neutrophil infiltration and obstructive vasculitis with perivascular leakage 3 weeks postimmunization. OCTA revealed a significant decrease in vascular flow in the deep capillary layer of the retina. Functional analysis showed that scotopic responses were intact at 2 weeks; however, normal photopic and scotopic responses were hardly detected in mice with EAU mice at 3 weeks postimmunization. Our data suggest that inflammatory cell activation and subsequent transcytosis induction in endothelial cells might be a major pathogenic factor for vascular leakage in uveitis, providing new insights into the pathophysiology of retinal vasculitis in noninfectious uveitis.Subject terms: Vasculitis, Imaging, Retina, Retina     

Cytotoxicity of Callerya speciosa Fractions against Myeloma and Lymphoma Cell Lines

Callerya speciosa is widely distributed in tropical and subtropical countries and is traditionally used for preventing numerous disorders. In this study, a bioguided fractionation of ethyl acetate extract (SE) from C. speciosa root was carried out to target antioxidant and cytotoxic activities. Of the four fractions (SE1-SE4) obtained by column chromatography, SE4 had the strongest anti-radical ability in the DPPH and ABTS assays (IC₅₀ = 0.05 and 0.17 mg/mL, respectively), with results close to butylated hydroxytoluene (BHT), a common antioxidant agent. The cytotoxic activities against the selected cells were analyzed in this study by MTT assay. Accordingly, SE2, SE3, and SE4 significantly inhibited the viability of multiple myeloma cell lines, comprising U266 (IC₅₀ = 0.38, 0.09, and 0.11 mg/mL, respectively) and KMS11 (IC₅₀ = 0.09, 0.17, and 0.15 mg/mL, respectively), mantle cell lymphoma Mino (IC₅₀ = 0.08, 0.16, and 0.15 mg/mL, respectively), and the noncancerous cell line LCL (IC₅₀ = 0.40, 0.32, and 0.21 mg/mL, respectively). At a concentration of 125 µg/mL, SE2, SE3, and SE4 induced the cell apoptosis of U266 (32.2%, 53.2%, and 55.6%, respectively), KMS11 (36.9%, 40.8%, and 47.9%, respectively), Mino (36.6%, 39.8%, and 22.0%, respectively), and LCL (12.4%, 17.5%, and 23.5%, respectively) via annexin V assay. The dominant compounds detected in fractions by high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC-ESI-MS/MS), were identified as isoflavones. This is the first report describing C. speciosa as a promising natural source of antileukemia and antimyeloma agents, which may be useful for the development of blood cancer treatments.