12,861 results match your criteria polymers extended

Exploiting Ultrashort α,β-Peptides in the Colloidal Stabilization of Gold Nanoparticles.

Langmuir 2021 Sep 17. Epub 2021 Sep 17.

DISFARM-Dipartimento di Scienze Farmaceutiche, Sezione Chimica Generale e Organica "A. Marchesini", Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy.

Colloidal gold nanoparticles (GNPs) have found wide-ranging applications in nanomedicine due to their unique optical properties, ease of preparation, and functionalization. To avoid the formation of GNP aggregates in the physiological environment, molecules such as lipids, polysaccharides, or polymers are employed as GNP coatings. Here, we present the colloidal stabilization of GNPs using ultrashort α,β-peptides containing the repeating unit of a diaryl β-amino acid and characterized by an extended conformation. Read More

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September 2021

Design of Persistent and Stable Porous Radical Polymers by Electronical Isolation Strategy.

Angew Chem Int Ed Engl 2021 Sep 15. Epub 2021 Sep 15.

State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Institute of Polymer Optoelectronic Materials and Devices, No. 381 Wushan, Tianhe District, 510640, Guangzhou, CHINA.

Conjugated organic radical polymers with stable radical features are difficult to design because the π conjugation in the polymer backbones makes the radicals readily delocalize and tend to undergo covalent bonding processes. In this work, we report an electronical isolation strategy to design stable porous radical polymers by homocoupling reaction from a meta-position active monomer. The meta linkage ensures less conjugation in the polymer skeletons, localizes the resonant radicals, and prevent them from recombination. Read More

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September 2021

Constitutive Modelling of Polylactic Acid at Large Deformation Using Multiaxial Strains.

Polymers (Basel) 2021 Aug 31;13(17). Epub 2021 Aug 31.

IRC in Polymer Science and Technology, Mechanical and Energy Systems Engineering, Faculty of Engineering and Informatics, University of Bradford, Bradford BD7 1DP, UK.

Sheet specimens of a PLLA-based polymer have been extended at a temperature near to the glass transition in both uniaxial and planar tension, with stress relaxation observed for some time after reaching the final strain. Both axial and transverse stresses were recorded in the planar experiments. In all cases during loading, yielding at small strain was followed by a drop in true stress and then strain hardening. Read More

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Influence of Infill Pattern on Mechanical Behavior of Polymeric and Composites Specimens Manufactured Using Fused Filament Fabrication Technology.

Polymers (Basel) 2021 Aug 31;13(17). Epub 2021 Aug 31.

Department of Civil, Materials, and Manufacturing Engineering, University of Malaga, C/Dr. Ortiz Ramos s/n, 29071 Málaga, Spain.

This paper presents the results of a comparative evaluation of the tensile strength behaviors of parts obtained by additive manufacturing using fused filament fabrication (FFF) technology. The study investigated the influences of the deposition printing parameters for both polymers and fiber-reinforced polymers. Polymeric materials that are widely used in FFF were selected, including acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and nylon. Read More

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Postharvest Quality of Cherry Tomatoes Coated with Mucilage from Dragon Fruit and Irradiated with UV-C.

Polymers (Basel) 2021 Aug 30;13(17). Epub 2021 Aug 30.

Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.

Cherry tomatoes are climacteric fruits that have a limited shelf life. Over the years, many methods have been applied to preserve the fruit quality and safety of these fruits. In this study, a novel method of combining mucilage from dragon fruits and UV-C irradiation was carried out. Read More

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Polymer Vesicles for Antimicrobial Applications.

Polymers (Basel) 2021 Aug 28;13(17). Epub 2021 Aug 28.

Center of Scientific Technology, Ningxia Medical University, Yinchuan 750004, China.

Polymer vesicles, hollow nanostructures with hydrophilic cavity and hydrophobic membrane, have shown significant potentials in biomedical applications including drug delivery, gene therapy, cancer theranostics, and so forth, due to their unique cell membrane-like structure. Incorporation with antibacterial active components like antimicrobial peptides, etc., polymer vesicles exhibited enhanced antimicrobial activity, extended circulation time, and reduced cell toxicity. Read More

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Power discontinuity and shift of the energy onset of a molecular de-bromination reaction induced by hot-electron tunneling.

Nanoscale 2021 Sep 8. Epub 2021 Sep 8.

Donostia International Physics Center (DIPC), Paseo M Lardizabal 4, 20018 San Sebastián, Spain.

Understanding the mechanism of molecular dissociation under applied bias is a fundamental requirement to progress in (electro)-catalysis as well as in (opto)-electronics. The working conditions of a molecular-based device and the stability of chemical bonds can be addressed in metal-organic junctions by injecting electrons in tunneling conditions. Here, we have correlated the energy of de-bromination of an aryl group with its density of states in a self-assembled dimeric structure of 4'-bromo-4-mercaptobiphenyl adsorbed on a Au(111) surface. Read More

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September 2021

Functionalized polymeric patch for localized oxaliplatin delivery to treat gastric cancer.

Mater Sci Eng C Mater Biol Appl 2021 Sep 9;128:112302. Epub 2021 Jul 9.

Department of Pharmacy, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad Campus, Hyderabad 500078, Telangana State, India. Electronic address:

Localized delivery of chemotherapeutic agents allows extended drug exposure at the target site, thereby reducing systemic toxicity. We report the development of functionalized polymeric patch with unidirectional drug release to treat gastric cancer. The oxaliplatin-loaded patch was prepared by incorporating sodium carboxymethyl cellulose, hydroxypropyl cellulose and polyvinylpyrrolidone. Read More

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September 2021

Influence of solvent quality on depletion potentials in colloid-polymer mixtures.

J Chem Phys 2021 Aug;155(8):084904

Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050, USA.

As first explained by the classic Asakura-Oosawa (AO) model, effective attractive forces between colloidal particles induced by depletion of nonadsorbing polymers can drive demixing of colloid-polymer mixtures into colloid-rich and colloid-poor phases, with practical relevance for purification of water, stability of foods and pharmaceuticals, and macromolecular crowding in biological cells. By idealizing polymer coils as effective penetrable spheres, the AO model qualitatively captures the influence of polymer depletion on thermodynamic phase behavior of colloidal suspensions. In previous work, we extended the AO model to incorporate aspherical polymer conformations and showed that fluctuating shapes of random-walk coils can significantly modify depletion potentials [W. Read More

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Effect of Filler Particle Size on the Recyclability of Fly Ash Filled HDPE Composites.

Polymers (Basel) 2021 Aug 23;13(16). Epub 2021 Aug 23.

Department of Mechanical Engineering Technology, Yanbu Industrial College, Yanbu Al-Sinaiyah City 41912, Saudi Arabia.

Fly ash polymer composites are innovative high-performance materials that reduce the environmental worries and disposal complications of heavy industry produced fly ash. This study developed and characterized such composites of high-density polyethylene (HDPE) matrices and found that the use of small (50-90 µm) particles of fly ash could give rise to the tensile modulus (~95%) and tensile strength (~7%) of their reinforced composites when compared to neat HDPE materials. While these results themselves convey a strong message of how fly ash can be effectively utilized, this was not the key aim of the current study. Read More

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Improving Recycled Poly(lactic Acid) Biopolymer Properties by Chain Extension Using Block Copolymers Synthesized by Nitroxide-Mediated Polymerization (NMP).

Polymers (Basel) 2021 Aug 19;13(16). Epub 2021 Aug 19.

Polymer Synthesis Department, Centro de Investigación en Química Aplicada (CIQA), Blvd Enrique Reyna Hermosillo, Saltillo 25294, Coahuila, Mexico.

The aim of this contribution is to assess the use poly(styrene--glycidyl methacrylate--styrene) copolymers synthesized by nitroxide mediated polymerization (NMP) as chain extenders in the recycling of poly(lactic acid) biopolyester. Concisely, the addition of such block copolymers during the melt processing of recycled poly(lactic acid) (rPLA) leads to important increases in the viscosity average molecular weight of modified polymeric materials. Molar masses increase from 31,000 g/mol for rPLA to 48,000 g mol for the resulting rPLA/copolymer blends (bPLA). Read More

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Applications of Biopolymers for Drugs and Probiotics Delivery.

Polymers (Basel) 2021 Aug 15;13(16). Epub 2021 Aug 15.

Department of Health and Human Development, Stefan cel Mare University of Suceava, 720229 Suceava, Romania.

Research regarding the use of biopolymers has been of great interest to scientists, the medical community, and the industry especially in recent years. Initially used for food applications, the special properties extended their use to the pharmaceutical and medical industries. The practical applications of natural drug encapsulation materials have emerged as a result of the benefits of the use of biopolymers as edible coatings and films in the food industry. Read More

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Recent advances in synthesis and modification of carbon dots for optical sensing of pesticides.

J Hazard Mater 2021 Aug 10;422:126881. Epub 2021 Aug 10.

Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100193, China. Electronic address:

Serious threat from pesticide residues to the ecosystem and human health has become a global concern. Developing reliable methods for monitoring pesticides is a world-wide research hotspot. Carbon dots (CDs) with excellent photostability, low toxicity, and good biocompatibility have been regarded as the potential substitutes in fabricating various optical sensors for pesticide detection. Read More

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Selective Binding and Redox-Activity on Parallel G-Quadruplexes by Pegylated Naphthalene Diimide-Copper Complexes.

Molecules 2021 Aug 19;26(16). Epub 2021 Aug 19.

Department of Chemistry, University of Pavia, Via Taramelli 10, 27100 Pavia, Italy.

G-quadruplexes (G4s) are higher-order supramolecular structures, biologically important in the regulation of many key processes. Among all, the recent discoveries relating to RNA-G4s, including their potential involvement as antiviral targets against COVID-19, have triggered the ever-increasing need to develop selective molecules able to interact with parallel G4s. Naphthalene diimides (NDIs) are widely exploited as G4 ligands, being able to induce and strongly stabilize these structures. Read More

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Machine-Learning-Assisted Selective Synthesis of Semiconductive Silver Thiolate Coordination Polymer with Segregated Paths for Holes and Electrons.

Angew Chem Int Ed Engl 2021 Aug 24. Epub 2021 Aug 24.

Kwansei Gakuin University, School of Science and Technology, 2-1 Gakuen, 669-1337, Sanda, JAPAN.

Coordination polymers (CPs) with infinite metal-S bond networks have unique electrical conductivities and optical properties, thus drawing attention. However, the development of new (-M-S-) n -structured CPs is hindered by their crystallization difficulty. Herein, we use machine learning to optimize the synthesis of trithiocyanuric acid (H 3 ttc)-based semiconductive CPs with infinite Ag-S bond networks, report three CP crystal structures, and reveal that isomer selectivity is mainly determined by proton concentration in the reaction medium. Read More

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Ultra Sensitive Label-free Detection of Biomolecules Using Vertically Extended Drain Double Gate Si0.5Ge0.5 Source Tunnel FET.

IEEE Trans Nanobioscience 2021 Aug 23;PP. Epub 2021 Aug 23.

This work reports a vertically extended drain double gate Si0.5Ge0.5 source tunnel FET for the biomolecules detection using its electrical properties modulation in presence of biomolecules like cell, DNA, protein, etc. Read More

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Polymerization/depolymerization of actin cooperates with the morphology and stability of cell-sized droplets generated in a polymer solution under a depletion effect.

J Chem Phys 2021 Aug;155(7):075101

Faculty of Life and Medical Sciences, Doshisha University, Tatara, Kyotanabe, Kyoto 610-0394, Japan.

Intercellular fluids in living organisms contain high concentrations of macromolecules such as nucleic acid and protein. Over the past few decades, several studies have examined membraneless organelles in terms of liquid-liquid phase separation. These studies have investigated aggregation/attraction among a rich variety of biomolecules. Read More

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Infrared harmonic features of collagen models at B3LYP-D3: From amide bands to the THz region.

J Chem Phys 2021 Aug;155(7):075102

Department of Chemistry and NIS (Nanostructured Interfaces and Surfaces) Center, University of Torino, Via P. Giuria 7, 10125 Turin, Italy.

In this paper, we have studied the vibrational spectral features for the collagen triple helix using a dispersion corrected hybrid density functional theory (DFT-D) approach. The protein is simulated by an infinite extended polymer both in the gas phase and in a water micro-solvated environment. We have adopted proline-rich collagen models in line with the high content of proline in natural collagens. Read More

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Self-stick membrane based on grafted gum Arabic as active food packaging for cheese using cinnamon extract.

Int J Biol Macromol 2021 Aug 18;189:114-123. Epub 2021 Aug 18.

Dairy Science Department, Food Industries and Nutrition Research Division, National Research Centre, Dokki, Giza 12211, Egypt.

Encapsulation of volatile essential oils has been investigated to provide an active food packaging (AFP) material with more control over their fast release and pungent smell. In this work, Gum Arabic-based adhesive membrane was developed as a self-stick AFP material, delivering cinnamon essential oil (CEO) in vapor phase. Gum Arabic (GA) was grafted with butyl acrylate (BA) and hydroxyethyl methacrylate [GA-g-poly(BA-HEMA)]. Read More

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Dynamic Covalent Polyurethane Network Materials: Synthesis and Self-Healability.

Macromol Rapid Commun 2021 Aug 21:e2100391. Epub 2021 Aug 21.

Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, H4B 1R6, Canada.

Polyurethane (PU) has not only been widely used in the daily lives, but also extensively explored as an important class of the essential polymers for various applications. In recent years, significant efforts have been made on the development of self-healable PU materials that possess high performance, extended lifetime, great reliability, and recyclability. A promising approach is the incorporation of covalent dynamic bonds into the design of PU covalently crosslinked polymers and thermoplastic elastomers that can dissociate and reform indefinitely in response to external stimuli or autonomously. Read More

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Impact of macromolecular crowding on the mesomorphic behavior of lipid self-assemblies.

Biochim Biophys Acta Biomembr 2021 Aug 18;1863(12):183728. Epub 2021 Aug 18.

Instituto de Investigación Médica Mercedes y Martín Ferreyra - INIMEC (CONICET) - Universidad Nacional de Córdoba, Friuli 2434, 5016 Córdoba, Argentina; Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina. Electronic address:

Using LAURDAN fluorescence we observed that water dynamics measured at the interface of DOPC bilayers can be differentially regulated by the presence of crowded suspensions of different proteins (HSA, IgG, Gelatin) and PEG, under conditions where the polymers are not in direct molecular contact with the lipid interface. Specifically, we found that the decrease in water dipolar relaxation at the membrane interface correlates with an increased fraction of randomly oriented (or random coil) configurations in the polymers, as Gelatin > PEG > IgG > HSA. By using the same experimental strategy, we also demonstrated that structural transitions from globular to extended conformations in proteins can induce transitions between lamellar and non-lamellar phases in mixtures of DOPC and monoolein. Read More

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Mn -Phos-Tag Polyacrylamide for the Quantification of Protein Phosphorylation Levels.

Curr Protoc 2021 Aug;1(8):e221

Laboratory of Muscle and Cardiac Biophysics, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.

This paper provides a guideline for optimizing and utilizing Mn Phos-tag gel technology to separate phosphorylated proteins from their unphosphorylated counterparts. It provides key insights into methods for careful sample preparation and experimental directions for determining the appropriate Phos-tag gel compositions and electrophoresis and western blotting conditions. This protocol has been used to successfully resolve proteins extracted from cardiac and skeletal muscles. Read More

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N-Type Quinoidal Polymers Based on Dipyrrolopyrazinedione for Application in All-Polymer Solar Cells.

Chemistry 2021 Aug 18. Epub 2021 Aug 18.

Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China.

Conjugated molecules and polymers with intrinsic quinoidal structure are promising n-type organic semiconductors, which have been reported for application in field-effect transistors and thermoelectric devices. In principle, the molecular and electronic characteristics of quinoidal polymers can also enable their application in organic solar cells. Herein, two quinoidal polymers, named PzDP-T and PzDP-ffT, based on dipyrrolopyrazinedione were synthesized and used as electron acceptors in all-polymer solar cells (all-PSCs). Read More

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Synthetic Macrocycle Nanopore for Potassium-Selective Transmembrane Transport.

J Am Chem Soc 2021 Aug 17. Epub 2021 Aug 17.

Laboratory of Experimental Physical Biology, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.

Reproducing the structure and function of biological membrane channels, synthetic nanopores have been developed for applications in membrane filtration technologies and biomolecular sensing. Stable stand-alone synthetic nanopores have been created from a variety of materials, including peptides, nucleic acids, synthetic polymers, and solid-state membranes. In contrast to biological nanopores, however, furnishing such synthetic nanopores with an atomically defined shape, including deliberate placement of each and every chemical group, remains a major challenge. Read More

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Terpolymer-chitosan membranes as biomaterial.

J Biomed Mater Res A 2021 Aug 16. Epub 2021 Aug 16.

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP-CONICET, La Plata, Argentina.

The present study shows a novel copolymer synthesis, its application in the membrane design and the physicochemical and biological characterization of the biomaterial obtained. Terpolymer starting diisopropyl fumarate (F), vinyl benzoate (V) and 2-hydroxyethyl methacrylate (H) was prepared by thermal radical polymerization. This polymer (FVH) was obtained in several monomer ratios and characterized by spectroscopic and chromatographic methods (FTIR, H-NMR and SEC). Read More

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[ study of liposome-modified polyetheretherketone implant on bacteriostasis and osseointegration].

Beijing Da Xue Xue Bao Yi Xue Ban 2021 Aug;53(4):758-763

Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing 100081, China.

Objective: To develop dexamethasone plus minocycline-loaded liposomes (Dex/Mino liposomes) and apply them to improve bioinert polyetheretherketone (PEEK) surface, which could prevent post-operative bacterial contamination, enhance ossification for physiologic osseointegration, and finally reduce implant failure rates.

Methods: Dex/Mino liposomes were covalently grafted onto the PEEK surface using polydopamine (pDA) coating as a medium. Confocal laser scanning microscopy was used to confirm the binding of fluorescently labeled liposomes onto the PEEK substrate, and a microplate reader was used to semiquantitatively measure the average fluorescence intensity of fluorescently labeled liposome-decorated PEEK surfaces. Read More

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One-Pot Facile Synthesis of Double-Shelled Mesoporous Silica Microcapsules with an Improved Soft-Template Method for Sustainable Pest Management.

ACS Appl Mater Interfaces 2021 Aug 13;13(33):39066-39075. Epub 2021 Aug 13.

College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing 100193, China.

A controlled release formulation based on silica microcapsules is an ideal selection to improve both the effective utilization and duration of pesticides to decrease ecological damage. Herein, a simple and green method for preparing double-shelled microcapsules was developed using a newly prepared quaternary ammonium ionic liquid (IL) as the functional additive to entrap avermectin (Ave) in mesoporous silica nanospheres (MSNs) and tannic acid-Cu (TA-Cu) complex as the sealing agent to form the core-shell structure ([email protected]@TA-Cu). The obtained microcapsules with an average size of 538 nm had pH-responsive release property and good stability in soil. Read More

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Investigating Physio-Thermo-Mechanical Properties of Polyurethane and Thermoplastics Nanocomposite in Various Applications.

Polymers (Basel) 2021 Jul 27;13(15). Epub 2021 Jul 27.

Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor Darul Ehsan, Malaysia.

The effect of the soft and hard polyurethane (PU) segments caused by the hydrogen link in phase-separation kinetics was studied to investigate the morphological annealing of PU and thermoplastic polyurethane (TPU). The significance of the segmented PUs is to achieve enough stability for further applications in biomedical and environmental fields. In addition, other research focuses on widening the plastic features and adjusting the PU-polyimide ratio to create elastomer of the poly(urethane-imide). Read More

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Identification of a Chitooligosaccharide Mechanism against Bacterial Leaf Blight on Rice by In Vitro and In Silico Studies.

Int J Mol Sci 2021 Jul 27;22(15). Epub 2021 Jul 27.

School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.

This study focuses on a commercial plant elicitor based on chitooligosaccharides (BIG), which aids in rice plant growth and disease resistance to bacterial leaf blight (BLB). When the pathogen () vigorously attacks rice that has suffered yield losses, it can cause damage in up to 20% of the plant. Furthermore, is a seed-borne pathogen that can survive in rice seeds for an extended period. Read More

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Chitosan-Based Functional Films Integrated with Magnolol: Characterization, Antioxidant and Antimicrobial Activity and Pork Preservation.

Int J Mol Sci 2021 Jul 21;22(15). Epub 2021 Jul 21.

College of Food Engineering and Nutritional Science, Shanxi Normal University, Xi'an 710119, China.

The aims of this study were to develop the magnolol-chitosan films and study the positive effect of the combination of magnolol and chitosan. The addition of magnolol made the magnolol-chitosan films exhibit higher density (1.06-1. Read More

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