Search

Purpose: To evaluate the safety and efficacy of intravitreal injections of 0.5 mg conbercept in patients with choroidal neovascularization secondary to pathological myopia (pmCNV). Methods: The 177 pmCNV patients were randomly assigned in a 3:1 ratio to receive conbercept or sham injection, respectively. The conbercept group receive conbercept intravitreal injections administered on a pro re nata (PRN) basis after 3 monthly loading doses. The sham group received three consecutive monthly sham injections and then one conbercept injection followed by PRN conbercept intravitreal injections. Results: At month 3, the mean BCVA for the two groups were improved by 12.0 letters (conbercept group, from 54.05 letters to 66.05 letters) and 0.6 letters (sham group, from 49.77 letters to 50.33 letters), respectively (p < 0.001). The mean central retinal thickness (CRT) at month 3 in the two groups decreased 62.0 μm (conbercept group, from 348.90 μm to 286.18 μm) and 4.4 μm (sham group, from 347.86 μm to 343.47 μm) (p < 0.001). At month 9, the mean BCVA improved by 13.3 letters in the conbercept group and 11.3 letters in the sham group. The mean CRT decreased 73.6 μm in the conbercept group and 55.9 μm in the sham group (p < 0.001). The most common ocular adverse events were associated with intravitreal injections, such as conjunctival haemorrhage and increased intraocular pressure. Conclusion: Intravitreal injections of 0.5 mg conbercept provided improvement in visual and anatomical outcomes in pmCNV patients with low rates of ocular and nonocular safety events. [ABSTRACT FROM AUTHOR]

Summary: With an input‐side boost inductor, current source inverter (CSI) naturally has the unique performance of voltage boosting and continuous input current, but its switching devices need to have reverse blocking capability. Switched‐capacitor (SC) multilevel inverter (MLI) features self‐balancing capacitor voltages and flexible structure, but it suffers the problems of inrush charging current of capacitors and pulse input current. By combining the CSI's input characteristics and the SC‐MLI's output features, this work presents a new five‐level inverter. Its input current is continuous, and there is no inrush current. In addition, the voltage gain is improved to 2/(1−d), where d is the duty ratio of the inductor's charging mode. With the unique structure, the duty ratio ranges from 0 to 1, and it is independent of the modulation ratio of the inverter. This makes the control more flexible. In addition to topology, operation, and modulation, parameter design, power loss, and comparison study are analyzed in detail. Finally, simulation results with fuel cell as input, and experimental results are provided to verify the superior performance of the proposed inverter. [ABSTRACT FROM AUTHOR]

The purpose of this work is to use fewer components to generate more output levels for power interfaces of low dc voltage sources such as fuel cells. First, two switched‐capacitor voltage lifters (SCVLs) with similar structure and same function are summarized. Each of them uses a single capacitor and has the advantage of identical voltage stress for all components. Then, the SCVLs are combined with a T‐type unit to develop two 17‐level inverters. The SCVLs is responsible for voltage boosting, while the T‐type unit uses two flying capacitors to increase the number of output levels. In addition to the use of three capacitors, the two 17‐level inverters employ 13 and 14 semiconductor switches respectively, and all components' voltage stresses do not exceed the dc input voltage. Simple structure, reduced capacitors' count, and low components' voltage stress are the main merits of the proposed inverters compared with other 17‐level inverters. Beyond theoretical analysis, both steady‐state and dynamic performances are verified experimentally, and the highest efficiency measured by the experiment is up to 97.8%. [ABSTRACT FROM AUTHOR]

A new bioadditive for poly(vinyl chloride) (PVC), diethylhexyl thiazolopyridine dicarboxylate (BTD), was designed and synthesized by the esterification between 2‐ethylhexanol and thiazolopyridine dicarboxylic acid. The chemical structure of BTD was characterized by Fourier transform infrared spectroscopy and NMR. As a main plasticizer, BTD had higher plasticizing efficiency, thermal stability and migration resistance than dioctyl phthalate. Furthermore, due to the thiazolopyridine conjugated structure, BTD possessed strong ultraviolet (UV) absorption that endowed its plasticized PVC film with excellent UV shielding property. The biomass resource combined with the above high performances make BTD a very promising additive for PVC plasticization and anti‐UV application. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Purpose: This retrospective study analyzed the polymorphisms and phenotypic frequencies of CYP2C9, CYP2C19 and CYP2D6 in a Han Chinese population. Methods: Tests for polymorphisms of CYP2C9, CYP2C19 and CYP2D6 were performed in over 3000 (3099‐3931) samples using an Illumina HiSeq X Ten sequencer. Following the guidance of the PharmGKB and PharmVar databases, the polymorphisms of CYP2C9, CYP2C19 and CYP2D6 were transformed into phenotypes, which included ultrarapid metabolizers (UMs), rapid metabolizers (RMs), normal metabolizers (NMs), intermediate metabolizers (IMs) and poor metabolizers (PMs). Results: A total of 3122 samples were tested for polymorphisms in CYP2C9 and the overall polymorphism frequency was found to be 8.8%; the phenotypic frequency for CYP2C9 was 91.2% NMs, 8.23% IMs and 0.16%, PMs. The overall polymorphism frequency of CYP2C19 was tested in 3099 samples and found to be 60.1%; the phenotypic frequency for CYP2C19 was 39.9% NMs, with 1.06% RMs, 45.62% IMs and 13.42% PMs. The overall polymorphism frequency of CYP2D6 was tested in 3931 samples and found to be 88.04%; the phenotypic frequency of CYP2D6 was 95.43% NMs, 3.35% IMs and 0.52% PMs. Using 2690 samples, the polymorphisms and phenotypic distributions of CYP2C9, CYP2C19 and CYP2D6 were examined simultaneously. We found that 96.36% of the samples contained mutations while 66.51% corresponded with phenotypic changes. Conclusions: Polymorphisms and phenotypic changes of CYP2C9, CYP2C19 and CYP2D6 are relatively frequent in the Han Chinese population. Thus, preemptive pharmacogenetic testing of CYP2C9, CYP2C19 and CYP2D6 should be recommended prior to dosing substrate drugs. [ABSTRACT FROM AUTHOR]

Genetic polymorphisms impact biological responses to drugs. Current pharmacogenomics guidelines formulated by different countries, such as the Clinical Pharmacogenetics Implementation Consortium, the Dutch Pharmacogenetics Working Group, the Canadian Pharmacogenomics Network for Drug Safety, and the French National Network (Réseau) of Pharmacogenetics, play important roles in clinical practices. However, the standards for these guidelines vary significantly, resulting in differences in recommendations. The present article discusses these differences by head‐to‐head comparison of the existing pharmacogenomics guidelines and proposes new strategies for their future development. [ABSTRACT FROM AUTHOR]

This study develops a new type of moisture-sensitive shape memory polymer based on zwitterionic copolymers synthesized with acrylic acid (AA) and 3-Dimethyl (methacryloyloxyethyl) ammonium propane sulfonate (DMAPS). The moisture absorption properties of zwitterionic copolymers are particularly investigated in this paper. The results demonstrate that the DMAPS/AA copolymers possess a sulfobetaine structure and form a two-phase separation structure. The zwitterionic copolymers show both good hydrophilic properties and moisture absorption properties. Both AA and DMAPS segments influence the hydrophilic properties and moisture absorption of the composite copolymer. The moisture absorption process is well modeled by Fick's second law in its initial stage. The moisture absorption is mainly determined by immersion conditions and the given materials' structure. Moisture absorption speed and saturated moisture absorption both increase with an increase in DMAPS content as well as the immersion temperature. The increased moisture absorption rate and higher saturated moisture absorption results from the higher activation energy of diffusion. The DMAPS/AA copolymers demonstrate adequate moisture-sensitive shape memory effects. Stain recovery is faster in the zwitterionic copolymers containing higher DMAPS content, whereas the final shape recovery decreases with an increase of DMAPS content. Finally, it is proposed that not only good moisture absorption units are required but also physical crosslinks should be improved for moisture-sensitive shape memory polymers. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Researchers are actively developing shape memory polymers (SMPs) for smart biomaterials. This paper reports a new SMP system synthesized from biocompatible 2-(dimethylamino) ethyl methacrylate (DMAEMA), butyl acrylate (BA) and tri(ethylene glycol) divinyl ether (TDE). Preliminary results show that the DMAEMA-co-BA-co-TDE copolymers form micelles in aqueous solution due to chemical crosslinking and hydrophobicity. The micelle size decreased with the increase in the BA content since the hydrophobicity of copolymers increases with the increase of BA content. The resulting polymer films contain-N(CH3)2 functional groups for further biomaterial applications. The thermal stability of DMAEMA-co-BA-co-TDE copolymers is determined by the DMAEMA structure and content. Moreover, the copolymers form micro-phase-separated structures containing a reversible amorphous soft phase, and the storage moduli decreases significantly around Tg. Therefore, good thermal-induced shape memory effects are achieved in the DMAEMA-co-BA-co-TDE copolymers by adjusting the BA content. This work proposes a new strategy for designing smart biomaterials using a biocompatible monomer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42312. [ABSTRACT FROM AUTHOR]

In this study, a series of shape memory polyurethanes ( SMPUs) were synthesized successfully by the bulk polymerization method from liquefied 4,4′-diphenylmethane diisocyanate (L- MDI), 1,4-butanediol ( BDO) and polyethylene glycol ( PEG). The influence of the hard segment content ( HSC) on the structure, morphology, properties and biocompatibility of PEG based SMPUs ( PEGSMPUs) was carefully investigated. The results show that a microphase separation structure composed of a semicrystalline soft phase and an amorphous hard phase is formed in the PEG6000/L- MDI/ BDO system. Crystallization of the PEG soft segment is influenced by the hard segments. The PEG semicrystalline soft phase serves as a reversible phase while the L- MDI− BDO hard segment acts as physical netpoints. Finally, a cyclic tensile test shows that all PEGSMPUs have good shape recovery (e.g. above 80%), whereas good shape fixity can only be achieved when the HSC is less than 35 wt%. The Cell Counting Kit 8 assay also demonstrates that only PEGSMPUs containing less than 40 wt% HSC have low cytotoxicity. It is thus concluded that PEGSMPUs bearing both good shape memory effects and good biocompatibility can be used as shape memory materials for biomedical applications when the HSC is less than 35 wt%. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Two-way shape changing polymers are attractive in recent years. In this short communication, carbon black (CB)/shape memory polyurethane (SMPU)-elastic polyurethane (EPU) laminated composite is prepared and electro-active two-way shape changing behavior is reported for the first time. First, the CB/SMPU composite demonstrates good electro-active shape recovery due to good electricity conduction. When the CB/SMPU composite film is elongated and form polymer laminates by combining with EPU substrate, the resulted CB/SMPU-EPU polymer laminate shows electro-active two-way shape changing behavior, e.g., bending by applying electric current, and reverse bending upon cooling without electric current. [ABSTRACT FROM AUTHOR]

ABSTRACT This article demonstrates a comparative investigation about the effect of diisocyanate on pyridine containing shape memory polyurethanes (Py-SMPUs), which are synthesized with N, N-bis(2-hydroxylethyl)isonicotinamide (BINA) and four different diisocyanates: 1,6-hexanediisocyante (HDI), isophorone diisocyanate (IPDI), methylene diphenyl diisocyanate (MDI), and tolylene diisocyanate (TDI). Results show that all BINA-SMPU systems have amorphous reversible phase. Comparatively, the MDI-BINA and TDI-BINA systems show higher Tg; and the HDI-BINA and IPDI-BINA systems show better thermal stability. In addition, the HDI-BINA and the IPDI-BINA systems exhibit good thermal-induced shape memory effect and good moisture-sensitive shape memory effect due to their better moisture absorption properties. Particularly, the HDI-BINA system has better response speed and better shape recovery. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40721. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents a facile preparation method of shape memory polyurethane (SMPU) by polyurethane blending from commercial thermoplastic polyurethane (PUA) with designed polyurethane (PUB). Structure, morphology, and shape memory behaviors of SMPU blends are investigated systematically. The results show that the PUB and PUA are miscible in the SMPU blends. When the PUB content is higher than 40 wt %, the Tg of SMPU blends is adjusted to above room temperature. As the PUA content increases, the PUA phase changes gradually from a droplet-like dispersion phase to continuous soft phase, whereas the PUB phase changes from a continuous hard phase to a droplet-like dispersion hard phase. SMPU blends show good shape memory effect when the PUA is blended with more than 40 wt % PUB. Thus, the commercialization of SMPU can be promoted greatly through the polyurethane blending from the commercial thermoplastic polyurethanes with polyurethane containing higher hard segment content. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4047-4053, 2013 [ABSTRACT FROM AUTHOR]

Background The spoilage bacterial community in oyster gill was investigated during storage at 4, 10 and 20°C. Aerobic plate counts and pH values were determined. Total bacterial DNA was extracted from oyster gill and bulk cells of plate count media. The major bacterial species during fresh or different temperatures storage were determined by polymerase chain reaction-denaturing gradient gel electrophoresis ( PCR-DGGE). Results The initial aerobic plate count in oyster gill reached 6.70 log CFU g−1. PCR-DGGE fingerprinting analysis of the 16S rRNA gene V3 region revealed that most of the strains in fresh oyster gill belonged to the genera Lactococcus and Enterobacter. The major spoilage bacteria at a storage temperature of 20°C were Leuconostoc pseudomesenteroides, an uncultured bacterium, Cytophaga fermentans, Lactococcus lactis, Pseudoalteromonas sp., Enterococcus mundtii, Clostridium difficile and an uncultured Fusobacteria; those at 10°C were Lactococcus spp., Lactobacillus curvatus, Weissella confusa and C. difficile; those at 4°C were Lactococcus, Weissella, Enterobacter and Aeromonas. The other minor species were L. curvatus, Pseudomonas sp. and E. mundtii. Lactococcus spp. was the most common main spoilage bacteria in oyster gill during chilled storage. Conclusion PCR-DGGE revealed the complexity of the bacterial microbiota and the major bacteria species in oyster gill for fresh and storage. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Shape memory polymers have been much researched in recent years. In the work reported, moisture-sensitive shape memory effects (SMEs) of novel pyridine-containing shape memory polyurethanes (Py-SMPUs) were investigated systematically. The results show that the strain recovery start immersion time ( ts), strain recovery immersion time ( tr) and final strain recovery immersion time ( te) are prolonged with a decrease of relative humidity as well as a decrease of temperature. The final strain recovery decreases with a decrease of relative humidity as well as an increase of temperature. The key component affecting the moisture-sensitive SME is the N, N-bis(2-hydroxyethyl)isonicotinamide (BINA) unit. The lower limit of BINA content for Py-SMPUs to exhibit a good moisture-sensitive SME is 30 wt%. The addition of diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) enhances the moisture-sensitive shape recovery. The final shape recovery decreases with a decrease of BINA content or an increase of MDI-BDO content. In addition, ts, tr and te become shorter in the Py-SMPUs with higher BINA content or with lower MDI-BDO content. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Non-covalent interactions are increasingly used in the molecular self-assembly of well-defined structures. In this study, a series of pyridine-containing polyurethanes (PUPys) were synthesized with diisocyanates and pyridine derivatives. Fourier transform infrared spectroscopy was employed to identify the vibration frequencies and investigate the relationship of shape memory effect (SME) and hydrogen-bonded supramolecular structure of the PUPys. The results show that a large fraction of strong hydrogen bonds are formed in the urethane group as well as in the pyridine ring. Moreover, the hydrogen bonding in the pyridine ring not only shows a response to a temperature stimulus in the PUPys, but is also responsive to moisture in N, N-bis(2-hydroxylethyl)isonicotinamine (BINA)/hexamethylene diisocyanate (HDI)-based PUPys; the hydrogen bonds in the urethane group have a higher dissociation temperature and show little response to moisture absorption. Accordingly, the PUPys are expected to show thermally induced and moisture-induced SMEs. Finally, the shape recovery process of films in the shape of flowers induced by temperature and moisture supports the idea that the PUPys could be used as thermally induced shape memory polymers (SMPs), and the BINA/HDI-based PUPys could be used as moisture-sensitive SMPs. Copyright © 2009 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The article presents a study which focused on the preparation of polyurethane (PU) nanofibers from PU/dimethylformamide (DMF) solutions using the electrospinning method. The study investigated the effects of various parameters including the applied voltage, feeding rate, and solution concentration on the diameters and morphology of PU nanofibers. The diameters and morphology of the nanofibers were found to be influenced greatly by the process parameters.

It is the first attempt to reveal the effect of reversible phase crystallization process on shape memory effect in shape memory polyurethane (PU) ionomer. Thereof the cyclic tensile testing was conducted with various cooling time to fix the temporary deformation for assessing shape memory function. The crystallization process of the reversible phase, poly ( ε-caprolactone) (PCL) in shape memory PU ionomers composed of different ionic group contents, 1,4-butanediol, 4,4′-methylenebis(phenyl isocyanate) and PCL, was investigated by using isothermal crystallization kinetics under the thermal routine similar to that for the cyclic tensile testing. The results demonstrate that the ionic groups within hard segments significantly slow down the crystal growth of the reversible phase. When the physical crosslink is strong enough, the crystallization rate would be a predominant factor determining the shape fixity ratio after various cooling time. Instead, when physical crosslink is weakening, the influence of crystallization rate is much less on the cooling time dependence of fixity. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article reports on the synthesis of shape-memory polyurethane (SMPU) ionomers using a prepolymerization method. According to the authors, the synthesis was done to demonstrate the crystallization properties of soft segments in the SMPU ionomers. They reveal that the more ionic groups there were within the hard segments, the lower the soft segments' crystallization rate become. Following isothermal crystallization, the melting behavior of the material indicated that the thermal history of the hard segments had a role in the crystallization mechanism.

In the present paper, a quasi-analytic method for solving structural optimization problems has been developed by co-ordinated use of mathematical transformations, high-quality approximation and a two-level approximation strategy. The method which has the advantages of both generality in applications and high efficiency in computations is especially of benefit to large practical design problems. Several typical examples of different sorts have been optimized to test its power. © 1998 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]