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https://www.readbyqxmd.com/read/28641405/biotransformation-of-ferulic-acid-to-protocatechuic-acid-by-corynebacterium-glutamicum-atcc-21420-engineered-to-express-vanillate-o-demethylase
#1
Naoko Okai, Takaya Masuda, Yasunobu Takeshima, Kosei Tanaka, Ken-Ichi Yoshida, Masanori Miyamoto, Chiaki Ogino, Akihiko Kondo
Ferulic acid (4-hydroxy-3-methoxycinnamic acid, FA) is a lignin-derived phenolic compound abundant in plant biomass. The utilization of FA and its conversion to valuable compounds is desired. Protocatechuic acid (3,4-dihydroxybenzoic acid, PCA) is a precursor of polymers and plastics and a constituent of food. A microbial conversion system to produce PCA from FA was developed in this study using a PCA-producing strain of Corynebacterium glutamicum F (ATCC 21420). C. glutamicum strain F grown at 30 °C for 48 h utilized 2 mM each of FA and vanillic acid (4-hydroxy-3-methoxybenzoic acid, VA) to produce PCA, which was secreted into the medium...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28641000/magnetic-properties-of-the-distorted-kagom%C3%A3-lattice-mn3-1-2-4-o2c-3c6h3-2
#2
Richard A Mole, Stephen Greene, Paul F Henry, Simon M Humphrey, Kirrily C Rule, Tobias Unruh, Gerald F Weldon, Dehong Yu, John A Stride, Paul T Wood
Kagomé lattice types have been of intense interest as idealized examples of extended frustrated spin systems. Here we demonstrate how the use of neutron diffraction and inelastic neutron scattering coupled with spin wave theory calculations can be used to elucidate the complex magnetic interactions of extended spin networks. We show that the magnetic properties of the coordination polymer Mn3(1,2,4-(O2C)3C6H3)2, a highly distorted kagomé lattice, have been erroneously characterized as a canted antiferromagnet in previous works...
June 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28640998/oximes-and-hydrazones-in-bioconjugation-mechanism-and-catalysis
#3
Dominik K Kölmel, Eric T Kool
The formation of oximes and hydrazones is employed in numerous scientific fields as a simple and versatile conjugation strategy. This imine-forming reaction is applied in fields as diverse as polymer chemistry, biomaterials and hydrogels, dynamic combinatorial chemistry, organic synthesis, and chemical biology. Here we outline chemical developments in this field, with special focus on the past ∼10 years of developments. Recent strategies for installing reactive carbonyl groups and α-nucleophiles into biomolecules are described...
June 22, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28640997/from-1d-polymers-to-2d-polymers-preparation-of-free-standing-single-monomer-thick-two-dimensional-conjugated-polymers-in-water
#4
Na Zhang, Taisheng Wang, Xing Wu, Chen Jiang, Taiming Zhang, Bangkun Jin, Hengxing Ji, Wei Bai, Ruke Bai
Recently, investigation on two-dimensional (2D) organic polymers has been made a great progress and conjugated 2D polymers already play a dynamic role in both academic and practical applications. However, a convenient, non-interfacial approach to obtain single-layer 2D polymers in solution, especially in aqueous media remains challenging. Herein, we present a facile, highly efficient and versatile "1D to 2D" strategy for preparation of free-standing single-monomer-thick conjugated 2D polymers in water without any aid...
June 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28640995/colloidal-gold-nanoparticles-induce-changes-in-cellular-and-subcellular-morphology
#5
Xiaowei Ma, Raimo Hartmann, Dorleta Jimenez de Aberasturi, Fang Yang, Stefaan J H Soenen, Bella B Manshian, Jonas Franz, Daniel Valdeperez, Beatriz Pelaz, Neus Feliu, Norbert Hampp, Christoph Riethmüller, Henning Vieker, Natalie Frese, Armin Gölzhäuser, Michael Simonich, Robert L Tanguay, Xing-Jie Liang, Wolfgang J Parak
Exposure of cells to colloidal nanoparticles (NPs) can have concentration-dependent harmful effects. Mostly, such effects are monitored with biochemical assays or probes from molecular biology, i.e. viability assays, gene expression profiles, etc., neglecting that the presence of NPs can also drastically affect cellular morphology. In the case of polymer-coated Au NPs we demonstrate that upon NP internalization, cells undergo lysosomal swelling, alterations in mitochondrial morphology, disturbances in actin and tubulin cytoskeleton and associated signaling, and reduction of focal adhesion contact area and number of filopodia...
June 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28640993/locking-in-optimal-nanoscale-structure-induced-by-naphthalenediimide-based-polymeric-additive-enables-efficient-and-stable-inverted-polymer-solar-cells
#6
Kwang Hyun Park, Yujin An, Seungon Jung, Hyesung Park, Changduk Yang
Operational stability and high performance are the most critical issues that must be addressed in order to propel and advance the current polymer solar cell (PSC) technology to the next level such as manufacturing and mass production. Herein, we report a high power conversion efficiency (PCE) of 11.2% together with an excellent device stability in PTB7-Th:PC71BM-based PSCs in the inverted structure by introducing the n-type P(NDI2OD-T2) macromolecular additive (>75% PCE retention at high temperature up to 120 °C, >97% PCE retention after 6 months in inert conditions, >93% PCE retention after 2 months in air with encapsulation, and >80% PCE retention after 140 h in air without encapsulation)...
June 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28640936/preparation-single-molecule-manipulation-and-energy-transfer-investigation-of-a-polyfluorene-graft-dna-polymer
#7
Mikael Madsen, Rasmus S Christensen, Abhichart Krissanaprasit, Mette R Bakke, Camilla F Riber, Karina S Nielsen, Alexander Zelikin, Kurt Vesterager Gothelf
Conjugated polymers have been intensively studied due to their unique optical and electronic properties combined with their physical flexibility and scalable bottom up synthesis. While the bulk qualities of conjugated polymers have been extensively utilized in research and industry, the ability to handle and manipulate conjugated polymers at the nanoscale lacks significantly behind. Here we extend the toolbox for controlled manipulation of conjugated polymers through the synthesis of a polyfluorene-DNA graft type polymer (poly(F-DNA))...
June 22, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28640627/chemical-modification-of-n-type-material-naphthalene-diimide-on-ito-for-efficient-and-stable-inverted-polymer-solar-cells
#8
Zhendong Li, Yanfeng Liu, Kai-Cheng Zhang, Zhao-Wei Wang, Peng Huang, Dahua Li, Yi Zhou, Bo Song
In order to provide orthogonal solvent processible surface modification and improve device stability of bulk-heterojunction polymer solar cells (PSCs), n-type semiconducting material naphthalene diimide (NDI) was chemically introduced on ITO surface as cathode interlayer (CIL) using 3-bromopropyltrimethoxysilane (BrTMS) as coupling agent. After modification, the work function of ITO can be decreased from 4.70 eV to 4.23 eV. The modified ITO cathode was applied in inverted PSCs based on PTB7-Th:PC71BM. With the CIL modification, a champion power conversion efficiency (PCE) of 5...
June 22, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28640614/role-of-polymeric-coating-on-the-phosphate-availability-as-fertilizer-insight-from-phosphate-release-in-soil-castor-polyurethane-coatings
#9
Diego Cruz, Ricardo Bortoletto-Santos, Gelton Guimarães, Wagner Luiz Polito, Caue Ribeiro
The coating of fertilizers with polymers is an acknowledged strategy for controlling the release of nutrients and their availability in soil. However, its effectiveness in the case of soluble phosphate fertilizers is still uncertain, and information is lacking concerning the chemical properties and structures of such coatings. Here, an oil-based hydrophobic polymer system (polyurethane) is proposed for control of the release of phosphorus from diammonium phosphate (DAP) granules. This material was systematically characterized, with evaluation of the delivery mechanism and the availability of phosphate in an acid soil...
June 22, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28640589/ru-bpy-32-incorporated-luminescent-polymer-dots-double-enhanced-electrochemiluminescence-for-detection-of-single-nucleotide-polymorphism
#10
Yaqiang Feng, Feng Sun, Ningning Wang, Jianping Lei, Huangxian Ju
Encapsulating a large amount of electrochemiluminescence (ECL) active molecules into one nanoparticle for single target recognition can greatly improve the sensitivity of ECL assay. This work used luminescent conjugated polymer as a carrier to synthesize Ru(bpy)32+ doped polymer dots (RuPdots). The RuPdots with an average size of 20 nm and encapsulation of about 1354 Ru(bpy)32+ showed greatly enhanced ECL emission. Using tripropylamine as a co-reactant, the resonance energy transfer from the excited polymer dots to the encapsulated Ru(bpy)32+ was demonstrated, which led to 15...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28640585/thermally-and-electrically-triggered-triple-shape-memory-behavior-of-poly-vinyl-acetate-poly-lactic-acid-due-to-graphene-induced-phase-separation
#11
Mohammad Sabzi, Masoud Babaahmadi, Mohammadreza Rahnama
This work aimed to develop a facile and broadly applicable method for fabricating a multi-stimuli responsive triple-shape memory polymer (SMP). Hence, herein the SMPs were prepared through the simple physical blending of two commercially available biopolymers, poly(lactic acid) (PLA) and poly(vinyl acetate) (PVAc), in the presence of robust and conductive graphene nanoplatelets. Interestingly, atomic force microscopy (AFM) observations and thermal analyses revealed that the presence of nanofillers led to phase separation and appearance of two well-separated transition temperatures in the blend of these two miscible polymers...
June 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28634933/3d-cell-culture-in-interpenetrating-networks-of-alginate-and-rbm-matrix
#12
Katrina Wisdom, Ovijit Chaudhuri
Altered tissue mechanical properties have been implicated in many key physiological and pathological processes. Hydrogel-based materials systems, made with native extracellular matrix (ECM) proteins, nonnative biopolymers, or synthetic polymers are often used to study these processes in vitro in 3D cell culture experiments. However, each of these materials systems present major limitations when used in mechanobiological studies. While native ECM-based hydrogels may enable good recapitulation of physiological behavior, the mechanics of these hydrogels are often manipulated by increasing or decreasing the protein concentration...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28637350/structural-peculiarities-of-ion-conductive-organic-inorganic-polymer-composites-based-on-aliphatic-epoxy-resin-and-salt-of-lithium-perchlorate
#13
Liubov Matkovska, Maksym Iurzhenko, Yevgen Mamunya, Igor Tkachenko, Valeriy Demchenko, Volodymyr Synyuk, Andriy Shadrin, Gisele Boiteux
The article is concerned with hybrid amorphous polymers synthesized basing on epoxy oligomer of diglycide aliphatic ester of polyethylene glycol that was cured by polyethylene polyamine and lithium perchlorate salt. Structural peculiarities of organic-inorganic polymer composites were studied by differential scanning calorimetry, wide-angle X-ray spectra, infrared spectroscopic, scanning electron microscopy, elemental analysis, and transmission and reflective optical microscopy. On the one hand, the results showed that the introduction of LiClO4 salt into epoxy polymer leads to formation of the coordinative metal-polymer complexes of donor-acceptor type between central Li(+) ion and ligand...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28636894/effects-of-hpmc-substituent-pattern-on-water-up-take-polymer-and-drug-release-an-experimental-and-modelling-study
#14
Diego Caccavo, Gaetano Lamberti, Anna Angela Barba, Susanna Abrahmsén-Alami, Anna Viridén, Anette Larsson
The purpose of this study was to investigate the hydration behavior of two matrix formulations containing the cellulose derivative hydroxypropyl methylcellulose (HPMC). The two HPMC batches investigated had different substitution pattern along the backbone; the first one is referred to as heterogeneous and the second as homogenous. The release of both the drug molecule theophylline and the polymer was determined. Additionally, the water concentrations at different positions in the swollen gel layers were determined by Magnetic Resonance Imaging...
June 18, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28636893/controlled-release-from-aspirin-based-linear-biodegradable-poly-anhydride-esters-for-anti-inflammatory-activity
#15
Queeny Dasgupta, Sahitya Movva, Kaushik Chatterjee, Giridhar Madras
This work reports the synthesis of a novel, aspirin-loaded, linear poly (anhydride ester) and provides mechanistic insights into the release of aspirin from this polymer for anti-inflammatory activity. As compared to conventional drug delivery systems that rely on diffusion based release, incorporation of bioactives in the polymer backbone is challenging and high loading is difficult to achieve. In the present study, we exploit the pentafunctional sugar alcohol (xylitol) to provide sites for drug (aspirin) attachment at its non-terminal OH groups...
June 18, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28636820/experimental-and-theoretical-study-of-ionic-pair-dissociation-in-lithium-ion-linear-polyethyleneimine-polyacrylonitrile-blend-for-solid-polymer-electrolytes
#16
Fernando Pignanelli, Mariano Romero, Ricardo Faccio, Álvaro W Mombrú
Herein, we report the preparation and characterization of novel polymeric blend between linear polyethylene imine (PEI) and polyacrylonitrile (PAN), with the purpose to facilitate the dissociation of lithium perchlorate salt (LiClO4) and thus to enhance Li-ion transport. It is a joint theoretical and experimental procedure for evaluating and thus demonstrating, the lithium salt dissociation. The procedure implies the correlation between theoretical pair distribution function (PDF) and conventional X-rays diffraction (XRD) by means of molecular dynamics (MD) approach...
June 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28636657/novel-sirna-formulation-to-effectively-knockdown-mutant-p53-in-osteosarcoma
#17
Anup K Kundu, Swathi V Iyer, Sruti Chandra, Amit S Adhikari, Tomoo Iwakuma, Tarun K Mandal
OBJECTIVES: The tumor suppressor p53 plays a crucial role in the development of osteosarcoma. The primary objective of this study is to develop and optimize lipid based nanoparticle formulations that can carry siRNA and effectively silence mutant p53 in 318-1, a murine osteosarcoma cell line. METHODS: The nanoparticles were composed of a mixture of two lipids (cholesterol and DOTAP) and either PLGA or PLGA-PEG and prepared by using an EmulsiFlex-B3 high pressure homogenizer...
2017: PloS One
https://www.readbyqxmd.com/read/28636622/inhibition-of-hepatitis-b-viral-entry-by-nucleic-acid-polymers-in-heparg-cells-and-primary-human-hepatocytes
#18
Clément Guillot, Nora Martel, Françoise Berby, Isabelle Bordes, Olivier Hantz, Matthieu Blanchet, Camille Sureau, Andrew Vaillant, Isabelle Chemin
Hepatitis B virus (HBV) infection remains a major public health concern worldwide with 240 million individuals chronically infected and at risk of developing cirrhosis and hepatocellular carcinoma. Current treatments rarely cure chronic hepatitis B infection, highlighting the need for new anti-HBV drugs. Nucleic acid polymers (NAPs) are phosphorothioated oligonucleotides that have demonstrated a great potential to inhibit infection with several viruses. In chronically infected human patients, NAPs administration lead to a decline of blood HBsAg and HBV DNA and to HBsAg seroconversion, the expected signs of functional cure...
2017: PloS One
https://www.readbyqxmd.com/read/28636400/click-biotinylation-of-plga-template-for-biotin-receptor-oriented-delivery-of-doxorubicin-hydrochloride-in-4t1-cell-induced-breast-cancer
#19
Yuvraj Singh, K K Durga Rao Viswanadham, Arun Kumar Jajoriya, Jayagopal Meher, Kavit Raval, Swati Jaiswal, Jayant Dewangan, H K Bora, Srikanta Kumar Rath, Jawahar Lal, Durga Prasad Mishra, Manish Kumar Chourasia
PLGA was functionalized with PEG and biotin using click chemistry to generate a biotin receptor targeted copolymer (Biotinylated-PEG-PLGA) which in turn was used to fabricate ultrafine nanoparticles (BPNP) of doxorubicin hydrochloride (DOX) for effective delivery in 4T1 cell induced breast cancer. However adequate entrapment of a hydrophilic bioactive like DOX in a hydrophobic polymer system made of PLGA is not usually possible. We therefore modified a conventional W/O/W emulsion method by utilizing ammonium chloride in the external phase to constrain DOX in dissolved polymer phase by supressing its inherent aqueous solubility as per common ion effect...
June 21, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28636389/tumor-microenvironment-responsive-multistaged-nanoplatform-for-systemic-rnai-and-cancer-therapy
#20
Xiaoding Xu, Phei Er Saw, Wei Tao, Yujing Li, Xiaoyuan Ji, Mikyung Yu, Morteza Mahmoudi, Jonathan Rasmussen, Dana Ayyash, Yuxiao Zhou, Omid C Farokhzad, Jinjun Shi
While RNA interference (RNAi) therapy has demonstrated significant potential for cancer treatment, effective and safe systemic delivery of RNAi agents such as small interfering RNA (siRNA) into tumor cells in vivo remains challenging. We herein reported a unique multistaged siRNA delivery nanoparticle (NP) platform, which is comprised of (i) a polyethylene glycol (PEG) surface shell, (ii) a sharp tumor microenvironment (TME) pH-responsive polymer that forms the NP core, and (iii) charge-mediated complexes of siRNA and tumor cell-targeting- and penetrating-peptide-amphiphile (TCPA) that are encapsulated in the NP core...
June 21, 2017: Nano Letters
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