scholarly journals Batch preparation and characterization of ZnO/PLGA/PCL nanofiber membranes for antibacterial materials

2021 ◽  
Author(s):  
Siqi Li ◽  
Jing Yin ◽  
Lan Xu
Keyword(s):  
Antibacterial Effect ◽  
Weight Ratio ◽  
Batch Preparation ◽  
Antibacterial Materials ◽  
Antibacterial Performance ◽  
Surgical Suture ◽  
Low Toxicity ◽  
Nanofiber Membranes ◽  
High Output

As biomaterials with excellent biocompatibility, biodegradation and low toxicity, poly(ε-caprolactone) (PCL) and poly(lactic-co-glycolic acid) (PLGA) are widely applied as wound dressing and surgical suture in biomedical field. In this paper, an oblique section free surface eletrospinning (OSFSE) apparatus was utilized to prepare high-quality and high-output ZnO/PLGA/PCL nanofiber membranes (NFMs) for antibacterial materials. The effects of the weight ratio of PLGA and PCL on the viscosity and conductivity of electrospinning solutions as well as the yield, morphology and wettability of PLGA/PCL NFMs were researched, and the optimal weight ratio of 6:4 was determined. Then the effects of ZnO contents on the electrospinning solution properties as well as the yield, morphology, structure, wettability, mechanical property and antibacterial performance of ZnO/PLGA/PCL NFMs with the optimal ratio of PLGA and PCL were studied. The results indicated that the addition of ZnO could improve significantly the antibacterial effect of NFMs, and the NFMs with 3 wt% ZnO had excellent antibacterial activity against E. coli (95.3%) and S. aureus (95.7%).

Antibacterial performance of Berberine loaded carrageenan/konjac glucomannan hydrogels

2021 ◽  
Vol 11 (9) ◽  
pp. 1516-1522
Author(s):  
Lei Jiang ◽  
Qiuxian Chen ◽  
Jia Liu ◽  
Zhongjie Zhu ◽  
Wei Shao
Keyword(s):  
Antibacterial Effect ◽  
Three Dimensional ◽  
Konjac Glucomannan ◽  
High Porosity ◽  
Release Behavior ◽  
Cell Compatibility ◽  
Antibacterial Materials ◽  
Antibacterial Performance ◽  
Dimensional Network ◽  
Good Cell

Carrageenan and konjac glucomannan are non-toxic polysaccharides which have been widely applied in the biomedical fields. Berberine as the antibacterial agent was successfully loaded into carrageenan/konjac glucomannan hydrogels. The Berberine loaded carrageenan/konjac glucomannan dried hydrogels display three-dimensional network structure, good swelling behavior and high porosity. These dried hydrogels also show controlled release behavior of Berberine. A good antibacterial effect towards S. aureus and C. albicans with good cell compatibility is exhibited. Thus, the fabricated Berberine loaded carrageenan/konjac glucomannan dried hydrogels could be considered as novel antibiotic alternative antibacterial materials.

Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE
Keyword(s):  
Normal Force ◽  
Weight Ratio ◽  
Good Combination ◽  
Rheological Characterization ◽  
Nonlinear Viscoelastic ◽  
Coating Composition ◽  
Linear And Nonlinear ◽  
Work Done ◽  
Tissue Production

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.

Carbon Dots for Bacterial Detection and Antibacterial Applications-A Minireview

2020 ◽  
Vol 25 (46) ◽  
pp. 4848-4860 ◽  
Author(s):  
Anisha Anand ◽  
Gopinathan Manavalan ◽  
Ranju Prasad Mandal ◽  
Huan-Tsung Chang ◽  
Yi-Ru Chiou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Antibacterial Effect ◽  
Bacterial Detection ◽  
High Brightness ◽  
Photo Catalysis ◽  
Wide Range ◽  
Prevention And Treatment ◽  
Low Toxicity ◽  
Conventional Antibiotics

: The prevention and treatment of various infections caused by microbes through antibiotics are becoming less effective due to antimicrobial resistance. Researches are focused on antimicrobial nanomaterials to inhibit bacterial growth and destroy the cells, to replace conventional antibiotics. Recently, carbon dots (C-Dots) become attractive candidates for a wide range of applications, including the detection and treatment of pathogens. In addition to low toxicity, ease of synthesis and functionalization, and high biocompatibility, C-Dots show excellent optical properties such as multi-emission, high brightness, and photostability. C-Dots have shown great potential in various fields, such as biosensing, nanomedicine, photo-catalysis, and bioimaging. This review focuses on the origin and synthesis of various C-Dots with special emphasis on bacterial detection, the antibacterial effect of CDots, and their mechanism.

scholarly journals Fabrication and Characterization of Electrospun Poly(acrylonitrile-co-Methyl Acrylate)/Lignin Nanofibers: Effects of Lignin Type and Total Polymer Concentration

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 992
Author(s):  
Suchitha Devadas ◽  
Saja M. Nabat Al-Ajrash ◽  
Donald A. Klosterman ◽  
Kenya M. Crosson ◽  
Garry S. Crosson ◽  
...  
Keyword(s):  
Methyl Acrylate ◽  
Lignin Content ◽  
Polymer Concentration ◽  
Weight Ratio ◽  
Electrospun Nanofibers ◽  
Polymer Content ◽  
Blend Ratio ◽  
Blend Ratios ◽  
Poly Acrylonitrile

Lignin macromolecules are potential precursor materials for producing electrospun nanofibers for composite applications. However, little is known about the effect of lignin type and blend ratios with synthetic polymers. This study analyzed blends of poly(acrylonitrile-co-methyl acrylate) (PAN-MA) with two types of commercially available lignin, low sulfonate (LSL) and alkali, kraft lignin (AL), in DMF solvent. The electrospinning and polymer blend solution conditions were optimized to produce thermally stable, smooth lignin-based nanofibers with total polymer content of up to 20 wt % in solution and a 50/50 blend weight ratio. Microscopy studies revealed that AL blends possess good solubility, miscibility, and dispersibility compared to LSL blends. Despite the lignin content or type, rheological studies demonstrated that PAN-MA concentration in solution dictated the blend’s viscosity. Smooth electrospun nanofibers were fabricated using AL depending upon the total polymer content and blend ratio. AL’s addition to PAN-MA did not affect the glass transition or degradation temperatures of the nanofibers compared to neat PAN-MA. We confirmed the presence of each lignin type within PAN-MA nanofibers through infrared spectroscopy. PAN-MA/AL nanofibers possessed similar morphological and thermal properties as PAN-MA; thus, these lignin-based nanofibers can replace PAN in future applications, including production of carbon fibers and supercapacitors.

scholarly journals Fabrication and Characterization of Electrospun Polycaprolactone Blended with Chitosan-Gelatin Complex Nanofibrous Mats

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongfang Qian ◽  
Zhen Zhang ◽  
Laijiu Zheng ◽  
Ruoyuan Song ◽  
Yuping Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Weight Ratio ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Tissue Engineering Scaffolds ◽  
Elongation At Break ◽  
Nanofibrous Scaffolds ◽  
Two Peaks

Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL) blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θof 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.

Abstract 1372: Characterization Of The Rejuvenation Of Cardiac Sympathetic Nerves In Cardiac Hypertrophy

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Kensuke Kimura ◽  
Masaki Ieda ◽  
Hideaki Kanazawa ◽  
Takahide Arai ◽  
Takashi Kawakami ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Fluorescent Protein ◽  
Sympathetic Neurons ◽  
Weight Ratio ◽  
Sympathetic Nerves ◽  
Marker Genes ◽  
List Type ◽  
Stellate Ganglia ◽  
Immature Neuron

Background : Cardiac hypertrophy induces the fetal isoform of genes (rejuvenation), including contractile proteins, ion channels, and natriuretic peptides. Cardiac sympathetic nerve function is known to be altered in cardiac hypertrophy and congestive heart failure. We recently reported that alteration of cardiac sympathetic nerves (CSN) was caused by their rejuvenation (Circ Res, 2007). The present study was designed to examine the precise characterization of the rejuvenation of CSN in cardiac hypertrophy. Methods and Results : RV hypertrophy was produced by consistent hypoxia (10% O 2 ) in C57/BL6 mice. RV pressure increased to 47 mmHg, and RV/(body weight) ratio increased by 1.6 fold. Nerve growth factor protein was augmented in hypertrophic RV, but was unchanged in LV. Double-transgenic mice, which specifically express eGFP (enhanced green fluorescent protein) in the sympathetic neurons, was generated by crossing dopamine β-hydroxylase (DBH)-Cre mice with Floxed-eGFP mice. The eGFP-positive CSN were markedly increased in hypertrophic RV, but not in LV. Nerve density, quantitated by immunostained area with eGFP and GAP43 (growth-associated corn marker), increased by 8.1 and 9.3 fold, respectively, in RV, but not in LV. (4) Catecholamine content was attenuated in RV. (5) Western blot revealed that tyrosine hydroxylase was markedly down-regulated in RV. (6) Immunostaining clearly demonstrated that the immature neuron markers, PSA-NCAM (highly polysialylated neural cell adhesion molecule) and Ulip-1 (Unc-33-like phosphoprotein 1), were expressed in CSN in hypertrophic RV and stellate ganglia. Basic helix-loop-helix transcription factor, Mash-1 (mammalian achaete-scute complex homolog 1) was strongly expressed in the stellate ganglia. (7) Immature neuron marker-immunopositive cells in stellate ganglia had a markedly decreased TH expression. Conclusion : The rejuvenated CSN showed various immature and fetal neuron marker genes at not only the peripheral axons but also the cellular bodies at the stellate ganglia. Rejuvenation of CSN might be critically involved in the alteration of sympathetic neuronal function in cardiac hypertrophy, including depressed norepinephrine synthesis and hyperinnervation.

The Elastic Characterization of Composite Based on Ultrasonic Waves

2021 ◽  
Author(s):  
Y. H. Park ◽  
J. Dana
Keyword(s):  
Composite Materials ◽  
Fatigue Failure ◽  
Elastic Constants ◽  
Material Properties ◽  
Weight Ratio ◽  
Transversely Isotropic ◽  
Ultrasonic Waves ◽  
Material Strength ◽  
Isotropic Composite

Abstract Anisotropic composite materials have been extensively utilized in mechanical, automotive, aerospace and other engineering areas due to high strength-to-weight ratio, superb corrosion resistance, and exceptional thermal performance. As the use of composite materials increases, determination of material properties, mechanical analysis and failure of the structure become important for the design of composite structure. In particular, the fatigue failure is important to ensure that structures can survive in harsh environmental conditions. Despite technical advances, fatigue failure and the monitoring and prediction of component life remain major problems. In general, cyclic loadings cause the accumulation of micro-damage in the structure and material properties degrade as the number of loading cycles increases. Repeated subfailure loading cycles cause eventual fatigue failure as the material strength and stiffness fall below the applied stress level. Hence, the stiffness degradation measurement can be a good indication for damage evaluation. The elastic characterization of composite material using mechanical testing, however, is complex, destructive, and not all the elastic constants can be determined. In this work, an in-situ method to non-destructively determine the elastic constants will be studied based on the time of flight measurement of ultrasonic waves. This method will be validated on an isotropic metal sheet and a transversely isotropic composite plate.

Characterization of Hot-Pressed Silicon Nitride Ceramics with Alkoxide-Derived Oxide Mixtures As the Sintering Aid

1992 ◽  
Vol 287 ◽  
Author(s):  
Y. Sato ◽  
C. Sakurai ◽  
M. Ueki ◽  
K. Sugita
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Weight Ratio ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Oxide Powders ◽  
Nitride Ceramics ◽  
Final Weight ◽  
Alkoxide Method

ABSTRACTA homogeneous mixture of Y2O3, CeO2 and MgO with a final weight ratio of 3:1: 2 was prepared by the alkoxide method. The powder mixture was then added into Si3N4 powder in amounts ranging from 4 to 12 wt%, andconsolidated by hot-pressing. Microstructure and mechanical properties of the sintered bodies were determined and compared to those of materials prepared by the conventional route of mixing the oxide powders as sintering aids individually in essentially same composition. The β-fraction (modification ratio) in same composition was higher in thesintered bodies made through the alkoxide method than those made through the conventional one. The room temperature flexural strength was maximized with 6wt% addition of the alkoxide derived oxide, whereas, 12wt% addition of the total oxide was required to maximize the strength by conventional processing.

scholarly journals Discovery and Characterization of Low-Molecular Weight Inhibitors of Erwinia tracheiphila

2020 ◽  
Vol 110 (5) ◽  
pp. 989-998
Author(s):  
Cláudio M. Vrisman ◽  
Loïc Deblais ◽  
Yosra A. Helmy ◽  
Reed Johnson ◽  
Gireesh Rajashekara ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
High Throughput Screening ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Bacillus Species ◽  
Erwinia Tracheiphila ◽  
Static Activity ◽  
Low Toxicity

Plant pathogenic bacteria in the genus Erwinia cause economically important diseases, including bacterial wilt of cucurbits caused by Erwinia tracheiphila. Conventional bactericides are insufficient to control this disease. Using high-throughput screening, 464 small molecules (SMs) with either cidal or static activity at 100 µM against a cucumber strain of E. tracheiphila were identified. Among them, 20 SMs (SM1 to SM20), composed of nine distinct chemical moiety structures, were cidal to multiple E. tracheiphila strains at 100 µM. These lead SMs had low toxicity to human cells and honey bees at 100 µM. No phytotoxicity was observed on melon plants at 100 µM, except when SM12 was either mixed with Silwet L-77 and foliar sprayed or when delivered through the roots. Lead SMs did not inhibit the growth of beneficial Pseudomonas and Enterobacter species but inhibited the growth of Bacillus species. Nineteen SMs were cidal to Xanthomonas cucurbitae and showed >50% growth inhibition against Pseudomonas syringae pv. lachrymans. In addition, 19 SMs were cidal or static against Erwinia amylovora in vitro. Five SMs demonstrated potential to suppress E. tracheiphila when foliar sprayed on melon plants at 2× the minimum bactericidal concentration. Thirteen SMs reduced Et load in melon plants when delivered via roots. Temperature and light did not affect the activity of SMs. In vitro cidal activity was observed after 3 to 10 h of exposure to these five SMs. Here, we report 19 SMs that provide chemical scaffolds for future development of bactericides against plant pathogenic bacterial species.

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