bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Ethyl Acetate and Trichloromethane Extracts from Phoebe zhennan Wood Residues and Application on the Preparation of UV Shielding Films
Authors: Pan Fangya , Chen Lin , He Lu , Jiang Yongze , Qi Jinqiu , Xiao Hui , Chen Yuzhu , Huang Xingyan , Hu Hongling , Tu Lihua , Lin Tiantian , Chen Gang , Hao Jianfeng , Xiao Yinlong , Xie Jiulong
Published: March 2020

In this work, ethyl acetate (EA) and trichloromethane (TR) extracts were extracted from Phoebe zhennan wood residues and the extracts were then applied to the preparation of UV shielding films (UV-SF). The results revealed that substances including olefins, phenols and alcohols were found in both EA and TR extracts, accounting for about 45% of all the detected substances. The two extracts had similar thermal stability and both had strong UV shielding ability. When the relative percentage of the extract is 1 wt% in solution, the extract solution almost blocked 100% of the UV-B (280–315 nm), and UV-A (315–400 nm). Two kinds of UV-SF were successfully prepared by adding the two extracts into polylactic acid (PLA) matrix. The UV-SF with the addition of 24 wt% of the extractive blocked 100% of the UV-B (280–315 nm) and more than 80% of the UV-A (315–400 nm). Moreover, the UV shielding performance of the UV-SF was still stable even after strong UV irradiation. Though the addition of extracts could somewhat decrease the thermal stability of the film, its effect on the end-use of the film was ignorable. EA extracts had less effect on the tensile properties of the films than TR extracts as the content of the extract reached 18%. The results of this study could provide fundamental information on the potential utilization of the extracts from Phoebe zhennan wood residues on the preparation of biobased UV shielding materials.
Photoluminescent Spectral Broadening of Lead Halide Perovskite Nanocrystals Investigated by Emission Wavelength Dependent Lifetime
Authors: Zhang Jinlei , He Jiuyang , Yang Lun , Gan Zhixing
Published: March 2020

Despite intensive efforts, the fluorescence of perovskite nanocrystals (NCs) still suffers from a poor color purity, which limits the applications in light emitting and multicolor display. A deep understanding on the fundamental of the photoluminescent (PL) spectral broadening is thus of great significance. Herein, the PL decay curves of the CsPbClxBr3-x NCs are monitored at different wavelengths covering the entire PL band. Moreover, energy relaxation time τ and radiative recombination time β are obtained by numerical fittings. The dependences of τ and 1/β on the detection wavelength agree well with the steady-state PL spectrum, indicating the observed PL broadening is an intrinsic effect due to the resonance and off-resonance exciton radiative recombination processes. This work not only provides a new analysis method for time-resolved PL spectra of perovskites, but also gains a deep insight into the spectral broadening of the lead halide perovskite NCs.
Manganese and Graphene Included Titanium Dioxide Composite Nanowires: Fabrication, Characterization and Enhanced Photocatalytic Activities
Authors: Lee Jun-Cheol , Gopalan Anantha-Iyengar , Saianand Gopalan , Lee Kwang-Pill , Kim Wha-Jung
Published: March 2020

We report the detailed microstructural, morphological, optical and photocatalytic studies of graphene (G) and manganese (Mn) co-doped titanium dioxide nanowires (TiO2(G–Mn) NWs) prepared through facile combined electrospinning–hydrothermal processes. The as-prepared samples were thoroughly characterized using X-ray diffraction (XRD), transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and diffuse reflectance spectroscopy (DRS). XRD studies reveal the formation of mixed anatase-rutile phases or rutile phase depending on the dopant (Mn) precursor concentrations in the electrospinning dope and calcination temperature. The evaluation of lattice parameters revealed that the incorporation of Mn species and carbon atoms in to the lattice of anatase or rutile TiO2 could occur through substituting the sites of oxygen atoms. XPS results confirm the existence of Mn2+/Mn3+ within the TiO2 NW. Raman spectroscopy provides the evidence for structural modification because of the graphene inclusion in TiO2 NW. The optical band gap of G–Mn including TiO2 is much lower than pristine TiO2 as confirmed through UV-vis DRS. The photocatalytic activities were evaluated by nitric oxide (NOx) degradation tests under visible light irradiation. Superior catalytic activity was witnessed for rutile G–Mn-co-doped TiO2 NW over their anatase counterparts. The enhanced photocatalytic property was discussed based on the synergistic effects of doped G and Mn atoms and explained by plausible mechanisms.
Ultraviolet Photodetecting and Plasmon-to-Electric Conversion of Controlled Inkjet-Printing Thin-Film Transistors
Authors: Wang Cheng-Jyun , You Hsin-Chiang , Ou Jen-Hung , Chu Yun-Yi , Ko Fu-Hsiang
Published: March 2020

Direct ink-jet printing of a zinc-oxide-based thin-film transistor (ZnO-based TFT) with a three-dimensional (3-D) channel structure was demonstrated for ultraviolet light (UV) and visible light photodetection. Here, we demonstrated the channel structures by which temperature-induced Marangoni flow can be used to narrow the channel width from 318.9 ± 44.1 μm to 180.1 ± 13.9 μm via a temperature gradient. Furthermore, a simple and efficient oxygen plasma treatment was used to enhance the electrical characteristics of switching ION/IOFF ratio of approximately 105. Therefore, the stable and excellent gate bias-controlled photo-transistors were fabricated and characterized in detail for ultraviolet (UV) and visible light sensing. The photodetector exhibited a superior photoresponse with a significant increase of more than 2 orders of magnitude larger drain current generated upon UV illumination. The results could be useful for the development of UV photodetectors by the direct-patterning ink-jet printing technique. Additionally, we also have successfully demonstrated that a metal-semiconductor junction structure that enables plasmon energy detection by using the plasmonic effects is an efficient conversion of plasmon energy to an electrical signal. The device showed a significant variations negative shift of threshold voltage under different light power density with exposure of visible light. With the ZnO-based TFTs, only ultraviolet light detection extends to the visible light wavelength.
Pituitary Glycoprotein Hormones in Human Milk before and after Pasteurization or Refrigeration
Authors: Vass Réka A. , Roghair Robert D. , Bell Edward F. , Colaizy Tarah T. , Johnson Karen J. , Schmelzel Mendi L. , Walker Jacky R. , Ertl Tibor
Published: March 2020

Our aims were to investigate the presence of pituitary glycoprotein hormones in preterm and donor milk, and to examine the effects of Holder pasteurization and refrigeration on the levels of these hormones. We measured follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid-stimulating hormone (TSH) in milk samples from mothers who delivered prematurely (n = 27) and in samples of mothers who delivered at term and donated milk to the Mother’s Milk Bank of Iowa (n = 30). The gonadotropins and TSH were present in similar amounts within human milk produced for preterm and term infants. FSH increased 21% after refrigeration (p < 0.05), while LH declined by 39% (p < 0.05). Holder pasteurization decreased LH by 24% (p < 0.05) and increased TSH by 17% (p < 0.05). Holder pasteurization followed by refrigeration resulted in a 21% increase in FSH and a 41% decrease in LH (both p < 0.05), resulting in more than a 3-fold increase in donor milk FSH:LH ratios (p < 0.05 versus fresh donor milk). Despite structural similarities, the gonadotropins are differentially impacted by Holder pasteurization and refrigeration, and this results in marked alterations in the relative amount of FSH and LH that may be administered to preterm infants, potentially swinging hormonal balance towards ovarian hyperstimulation in females and hypogonadism in males.
Large-Scale Screening of 239 Traditional Chinese Medicinal Plant Extracts for Their Antibacterial Activities against Multidrug-Resistant Staphylococcus aureus and Cytotoxic Activities
Authors: Kim Gowoon , Gan Ren-You , Zhang Dan , Farha Arakkaveettil Kabeer , Habimana Olivier , Mavumengwana Vuyo , Li Hua-Bin , Wang Xiao-Hong , Corke Harold
Published: March 2020

Novel alternative antibacterial compounds have been persistently explored from plants as natural sources to overcome antibiotic resistance leading to serious foodborne bacterial illnesses. In this study, the ethanolic extracts from 239 traditional Chinese medicinal plants (TCMP)’ materials were screened to discover promising candidates that have strong antibacterial properties against multidrug-resistant Staphylococcus (S.) aureus and low cytotoxicity. The results revealed that 74 extracts exhibited good antibacterial activities (diameter of inhibition zone (DIZ) ≥ 15 mm). Furthermore, 18 extracts (DIZ ≥ 20 mm) were determined their minimum inhibitory concentrations (MIC) and minimum bactericide concentrations (MBC), ranging from 0.1 to 12.5 mg/mL and 0.78 to 25 mg/mL, respectively. In addition, most of the 18 extracts showed relatively low cytotoxicity (a median lethal concentration (LC50) >100 µg/mL). The 18 extracts were further determined to estimate possible correlation of their phenolic contents with antibacterial activity, and the results did not show any significant correlation. In conclusion, this study selected out some promising antibacterial TCMP extracts with low cytotoxicity, including Rhus chinensis Mill., Ilex rotunda Thunb., Leontice kiangnanensis P.L.Chiu, Oroxylum indicum Vent., Isatis tinctorial L., Terminalia chebula Retz., Acacia catechu (L.f.) Willd., Spatholobus suberectus Dunn, Rabdosia rubescens (Hemsl.) H.Hara, Salvia miltiorrhiza Bunge, Fraxinus fallax Lingelsh, Coptis chinensis Franch., Agrimonia Pilosa Ledeb., and Phellodendron chinense C.K.Schneid.
Nanoparticle-Mediated Therapeutic Application for Modulation of Lysosomal Ion Channels and Functions
Authors: Lee Dongun , Hong Jeong Hee
Published: March 2020

Applications of nanoparticles in various fields have been addressed. Nanomaterials serve as carriers for transporting conventional drugs or proteins through lysosomes to various cellular targets. The basic function of lysosomes is to trigger degradation of proteins and lipids. Understanding of lysosomal functions is essential for enhancing the efficacy of nanoparticles-mediated therapy and reducing the malfunctions of cellular metabolism. The lysosomal function is modulated by the movement of ions through various ion channels. Thus, in this review, we have focused on the recruited ion channels for lysosomal function, to understand the lysosomal modulation through the nanoparticles and its applications. In the future, lysosomal channels-based targets will expand the therapeutic application of nanoparticles-associated drugs.
Combined Effect of Midazolam and Bone Morphogenetic Protein-2 for Differentiation Induction from C2C12 Myoblast Cells to Osteoblasts
Authors: Hidaka Yukihiko , Chiba-Ohkuma Risako , Karakida Takeo , Onuma Kazuo , Yamamoto Ryuji , Fujii-Abe Keiko , Saito Mari M. , Yamakoshi Yasuo , Kawahara Hiroshi
Published: March 2020

In drug repositioning research, a new concept in drug discovery and new therapeutic opportunities have been identified for existing drugs. Midazolam (MDZ) is an anesthetic inducer used for general anesthesia. Here, we demonstrate the combined effects of bone morphogenetic protein-2 (BMP-2) and MDZ on osteogenic differentiation. An immortalized mouse myoblast cell line (C2C12 cell) was cultured in the combination of BMP-2 and MDZ (BMP-2+MDZ). The differentiation and signal transduction of C2C12 cells into osteoblasts were investigated at biological, immunohistochemical, and genetic cell levels. Mineralized nodules formed in C2C12 cells were characterized at the crystal engineering level. BMP-2+MDZ treatment decreased the myotube cell formation of C2C12 cells, and enhanced alkaline phosphatase activity and expression levels of osteoblastic differentiation marker genes. The precipitated nodules consisted of randomly oriented hydroxyapatite nanorods and nanoparticles. BMP-2+MDZ treatment reduced the immunostaining for both α1 and γ2 subunits antigens on the gamma-aminobutyric acid type A (GABAA) receptor in C2C12 cells, but enhanced that for BMP signal transducers. Our investigation showed that BMP-2+MDZ has a strong ability to induce the differentiation of C2C12 cells into osteoblasts and has the potential for drug repositioning in bone regeneration.
Doxorubicin–Loaded Human Serum Albumin Submicron Particles: Preparation, Characterization and In Vitro Cellular Uptake
Authors: Chaiwaree Saranya , Prapan Ausanai , Suwannasom Nittiya , Laporte Tomás , Neumann Tanja , Pruß Axel , Georgieva Radostina , Bäumler Hans
Published: March 2020

Doxorubicin (DOX) is an effective anthracycline antibiotic drug which is commonly used in a broad range cancer therapy. However, due to dose depending side effects and toxicity to non-cancerous tissues, its clinical applications are restricted. To overcome these limitations, human serum albumin (HSA) has been investigated as a biocompatible drug delivery vehicle. In this study, human serum albumin submicron particles (HSA-MPs) were fabricated by using the Co-precipitation–Crosslinking–Dissolution technique (CCD technique) and DOX was loaded into the protein particles by absorption. DOX-HSA-MPs showed uniform peanut-like shape, submicron size and negative zeta-potential (−13 mV). The DOX entrapment efficiency was 25% of the initial amount. The in vitro release in phosphate buffered saline pH 7.4 was less than 1% within 5 h. In contrast, up to 40% of the entrapped DOX was released in presence of a protein digesting enzyme mixture (Pronase®) within the same time. In addition, in vitro cytotoxicity and cellular uptake of DOX-HSA-MPs were evaluated using the lung carcinoma cell line A549. The results demonstrated that DOX-HSA-MPs reduced the cell metabolic activities after 72 h. Interestingly, DOX-HSA-MPs were taken up by A549 cells up to 98% and localized in the cell lysosomal compartment. This study suggests that DOX-HSA-MPs which was fabricated by CCD technique is seen as a promising biopolymer particle as well as a viable alternative for drug delivery application to use for cancer therapy.
Hierarchical Porous Carbon—PLLA and PLGA Hybrid Nanoparticles for Intranasal Delivery of Galantamine for Alzheimer’s Disease Therapy
Authors: Nanaki Stavroula G. , Spyrou Konstantinos , Bekiari Chryssa , Veneti Pelagia , Baroud Turki N. , Karouta Niki , Grivas Ioannis , Papadopoulos Georgios C. , Gournis Dimitrios , Bikiaris Dimitrios N.
Published: March 2020

In the present study, poly(l-lactic acid) (PLLA) and poly(lactide-co-glycolide) (PLGA) hybrid nanoparticles were developed for intranasal delivery of galantamine, a drug used in severe to moderate cases of Alzheimer’s disease. Galantamine (GAL) was adsorbed first in hierarchical porous carbon (HPC). Formulations were characterized by FT-IR, which showed hydrogen bond formation between GAL and HPC. Furthermore, GAL became amorphous after adsorption, as confirmed by XRD and differential scanning calorimetry (DSC) studies. GAL was quantified to be 21.5% w/w by TGA study. Adsorbed GAL was nanoencapsulated in PLLA and PLGA, and prepared nanoparticles were characterized by several techniques. Their sizes varied between 182 and 394 nm, with an exception that was observed in nanoparticles that were prepared by PLLA and adsorbed GAL that was found to be 1302 nm in size. DSC thermographs showed that GAL was present in its crystalline state in nanoparticles before its adsorption to HPC, while it remained in its amorphous phase after its adsorption in the prepared nanoparticles. It was found that the polymers controlled the release of GAL both when it was encapsulated alone and when it was adsorbed on HPC. Lastly, PLGA hybrid nanoparticles were intranasally-administered in healthy, adult, male Wistar rats. Administration led to successful delivery to the hippocampus, the brain area that is primarily and severely harmed in Alzheimer’s disease, just a few hours after a single dose.
The First Case of Glyphosate Resistance in Johnsongrass (Sorghum halepense (L.) Pers.) in Europe
Authors: Vazquez-Garcia Jose G. , Palma-Bautista Candelario , Rojano-Delgado Antonia Maria , De Prado Rafael , Menendez Julio
Published: March 2020

Six Johnsongrass populations suspected of being glyphosate resistant were collected from railways and freeways near Cordoba (SW Spain), where glyphosate is the main weed control tool. The 50% reduction in shoot fresh weight (GR50) values obtained for these six populations ranged from 550.4 to 1169 g ae ha−1, which were 4.2 to 9 times greater than the value obtained for the susceptible population. Glyphosate was equally metabolized to the same extent in both resistant and susceptible populations, with no significant differences in either 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibition or basal activity. No amino acid substitutions were observed in any of the resistant populations. Slight but significant differences in glyphosate penetration were observed among some but not all of the resistant populations and for the times of incubation assayed, although these differences were not considered further. The proposed primary mechanism of resistance in these six glyphosate-resistant Johnsongrass populations is reduced herbicide translocation, because the amount of glyphosate that translocated from treated leaves to shoots and roots in the susceptible population was double that observed in the resistant populations. As glyphosate multiple resistance due to more than one mechanism is not uncommon, this is the first time that glyphosate-resistant Johnsongrass populations have been fully described for all known mechanisms.
Potential Role of Lolium multiflorum Lam. in the Management of Rice Weeds
Authors: Vitalini Sara , Orlando Francesca , Vaglia Valentina , Bocchi Stefano , Iriti Marcello
Published: March 2020

The phytotoxic relationships between crops and weeds can cover a role in weed management, reducing the use of chemical herbicides. Starting from the organic farmers’ experience, the study aimed to define the inhibitory action of Lolium multiflorum Lam., used as a cover crop before rice sowing, against Echinochloa oryzoides (Ard.) Fritsch, one of the main rice weeds. In vitro 7-day assays were carried out in Petri dishes to compare the effect of different L. multiflorum Lam. parts, in the form of aqueous extract or powder, on the seed germination and seedling growth of Oryza sativa L. and E. oryzoides and to verify the hypothesis of a higher susceptibility of the weed. The total polyphenolic content, as the potential source of allelochemicals, in the L. multiflorum parts was measured. The results showed that both species suffer the phytotoxic action of L. multiflorum, but a more marked effect against E. oryzoides was recorded. In according with the polyphenol quantities, stem and inflorescence extracts showed the more significant species-specific inhibition. In all assays, the weed showed a stronger reduction in the root length and seedling vigor index, and, in some cases, also in the germination percentage and shoot length compared to rice.
One-Step Reverse-Transcription Digital PCR for Reliable Quantification of Different Pepino Mosaic Virus Genotypes
Authors: Mehle Nataša , Gregur Larisa , Bogožalec Košir Alexandra , Dobnik David
Published: March 2020

In recent years, pepino mosaic virus (PepMV) has rapidly evolved from an emerging virus to an endemic pathogen, as it causes significant loses to tomato crops worldwide. At present, the main control strategy for prevention of PepMV disease in tomato production remains based on strict hygiene measures. To prevent damage caused by PepMV, cross-protection is used in some countries. Reliable characterisation, detection and quantification of the pathogen are vital for disease control. At present, reverse-transcription real-time quantitative polymerase chain reaction (RT-qPCR) is generally used for this purpose. However, quantitative use of RT-qPCR is linked to standardised reference materials, which are not available for PepMV. In addition, many factors can influence RT-qPCR efficiencies and lead to lower accuracy of the quantification. In this study, well-characterised PepMV-genotype-specific RT-qPCR assays were transferred to two digital PCR (dPCR) platforms. dPCR-based assays allow absolute quantification without the need for standard curves, and due to the binary nature of the reaction, dPCR also overcomes many of the other drawbacks of RT-qPCR. We have shown that these newly developed and validated PepMV-genotype-specific dPCR assays are suitable candidates for higher-order methods for quantification of PepMV RNA, as they show lower measurement variability, with sensitivity and specificity comparable to RT-qPCR.
Phylogenetic Analysis and Development of Molecular Tool for Detection of Diaporthe citri Causing Melanose Disease of Citrus
Authors: Chaisiri Chingchai , Liu Xiang-Yu , Lin Yang , Li Jiang-Bo , Xiong Bin , Luo Chao-Xi
Published: March 2020

Melanose disease caused by Diaporthe citri is considered as one of the most important and destructive diseases of citrus worldwide. In this study, isolates from melanose samples were obtained and analyzed. Firstly, the internal transcribed spacer (ITS) sequences were used to measure Diaporthe-like boundary species. Then, a subset of thirty-eight representatives were selected to perform the phylogenetic analysis with combined sequences of ITS, beta-tubulin gene (TUB), translation elongation factor 1-α gene (TEF), calmodulin gene (CAL), and histone-3 gene (HIS). As a result, these representative isolates were identified belonging to D. citri, D. citriasiana, D. discoidispora, D. eres, D. sojae, and D. unshiuensis. Among these species, the D. citri was the predominant species that could be isolated at highest rate from different melanose diseased tissues. The morphological characteristics of representative isolates of D. citri were investigated on different media. Finally, a molecular tool based on the novel species-specific primer pair TUBDcitri-F1/TUBD-R1, which was designed from TUB gene, was developed to detect D. citri efficiently. A polymerase chain reaction (PCR) amplicon of 217 bp could be specifically amplified with the developed molecular tool. The sensitivity of the novel species-specific detection was upon to 10 pg of D. citri genomic DNA in a reaction. Therefore, the D. citri could be unequivocally identified from closely related Diaporthe species by using this simple PCR approach.
PEGylated Thermo-Sensitive Bionic Magnetic Core-Shell Structure Molecularly Imprinted Polymers Based on Halloysite Nanotubes for Specific Adsorption and Separation of Bovine Serum Albumin
Authors: Li Xiufang , Liu Hui , Deng Zhiwei , Chen Wenqing , Li Tianhao , Zhang Yunshan , Zhang Zhuomin , He Yao , Tan Zhijian , Zhong Shian
Published: March 2020

Novel PEGylated thermo-sensitive bionic magnetic core-shell structure molecularly imprinted polymers (PMMIPs) for the specific adsorption and separation of bovine serum albumin (BSA) were obtained via a surface-imprinting technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), and specific surface area (BET), were adopted to demonstrate that novel PMMIPs were successfully synthesized. Subsequently, the prepared PMMIPs were used as the extractor for BSA and were combined with magnetic solid-phase extraction. The concentrations of BSA were detected by UV-vis spectrophotometry at 278 nm. The maximum adsorption capacity of the PMMIPs was 258 mg g−1, which is much higher than that of non-imprinted polymer (PMNIPs). PMMIPs showed favorable selectivity for BSA against reference proteins, i.e., bovine hemoglobin, ovalbumin and lysozyme. PMMIPs were further used to recognize BSA in protein mixtures, milk, urine and sewage, these results revealed that approximately 96% of the ideal-state adsorption capacity of PMMIPs for BSA was achieved under complicated conditions. Regeneration and reusability studies demonstrated that adsorption capacity loss of the PMMIPs was not obvious after recycling for four times. Facile synthesis, excellent adsorption property and efficient selectivity for BSA trapping are features that highlight PMMIPs as an attractive candidate for biomacromolecular purification.
Exploring NIR Aza-BODIPY-Based Polarity Sensitive Probes with ON-and-OFF Fluorescence Switching in Pluronic Nanoparticles
Authors: Saremi Bahar , Bandi Venugopal , Kazemi Shahrzad , Hong Yi , D’Souza Francis , Yuan Baohong
Published: March 2020

Because of their deep penetration capability in tissue, red or near infrared (NIR) fluorophores attract much attention in bio-optical imaging. Among these fluorophores, the ones that respond to the immediate microenvironment (i.e., temperature, polarity, pH, viscosity, hypoxia, etc.) are highly desirable. We studied the response of six NIR aza-BODIPY-based and structurally similar fluorophores to polarity and viscosity for incorporation inside Pluronic nanoparticles as switchable fluorescent probes (SFPs). Based on our results, all of these fluorophores were moderately to strongly sensitive to the polarity of the microenvironment. We concluded that attaching amine groups to the fluorophore is not necessary for having strong polarity sensitive probes. We further studied the response of the fluorophores when embedded inside Pluronic nanoparticles and found that four of them qualified as SFPs. We also found that the switching ratio of the fluorophore-encapsulated Pluronic nanoparticles (ION-to-IOFF) is related to the length of the hydrophobic chain of the Pluronic tri-block copolymers. As such, the highest switching ratio pertained to F-68 with the lowest hydrophobic block poly (propylene oxide) (PPO chain of only 30 units).
Novel 3D Hybrid Nanofiber Scaffolds for Bone Regeneration
Authors: Kołbuk Dorota , Heljak Marcin , Choińska Emilia , Urbanek Olga
Published: March 2020

Development of hybrid scaffolds and their formation methods occupies an important place in tissue engineering. In this paper, a novel method of 3D hybrid scaffold formation is presented as well as an explanation of the differences in scaffold properties, which were a consequence of different crosslinking mechanisms. Scaffolds were formed from 3D freeze-dried gelatin and electrospun poly(lactide-co-glicolide) (PLGA) fibers in a ratio of 1:1 w/w. In order to enhance osteoblast proliferation, the fibers were coated with hydroxyapatite nanoparticles (HAp) using sonochemical processing. All scaffolds were crosslinked using an EDC/NHS solution. The scaffolds’ morphology was imaged using scanning electron microscopy (SEM). The chemical composition of the scaffolds was analyzed using several methods. Water absorption and mass loss investigations proved a higher crosslinking degree of the hybrid scaffolds than a pure gelatin scaffold, caused by additional interactions between gelatin, PLGA, and HAp. Additionally, mechanical properties of the 3D hybrid scaffolds were higher than traditional hydrogels. In vitro studies revealed that fibroblasts and osteoblasts proliferated and migrated well on the 3D hybrid scaffolds, and also penetrated their structure during the seven days of the experiment.
Permeability and Antifouling Augmentation of a Hybrid PVDF-PEG Membrane Using Nano-Magnesium Oxide as a Powerful Mediator for POME Decolorization
Authors: Abdulsalam Mohammed , Che Man Hasfalina , Goh Pei Sean , Yunos Khairul Faezah , Zainal Abidin Zurina , Isma M.I. Aida , Ismail Ahmad Fauzi
Published: March 2020

This study focused on developing a hydrophilic hybrid polyvinylidene fluoride (PVDF)-polyethylene glycol (PEG) hollow membrane by incorporating Nano-magnesium oxide (NMO) as a potent antifouling mediator. The Nano-hybrid hollow fibers with varied loading of NMO (0 g; 0.25 g; 0.50 g; 0.75 g and 1.25 g) were spun through phase inversion technique. The resultants Nano-hybrid fibers were characterized and compared based on SEM, EDX, contact angle, surface zeta-potential, permeability flux, fouling resistance and color rejection from palm oil mill effluent (POME). Noticeably, the permeability flux, fouling resistance and color rejection improved with the increase in NMO loading. PVDF-PEG with 0.50 g-NMO loading displayed an outstanding performance with 198.35 L/m2·h, 61.33 L/m2·h and 74.65% of water flux, POME flux and color rejection from POME, respectively. More so, a remarkable fouling resistance were obtained such that the flux recovery, reversible fouling percentage and irreversible fouling percentage remains relatively steady at 90.98%, 61.39% and 7.68%, respectively, even after 3 cycles of continuous filtrations for a total period of 9 h. However, at excess loading of 0.75 and 1.25 g-NMO, deterioration in the flux and fouling resistance was observed. This was due to the agglomeration of nanoparticles within the matrix structure at the excessive loading.
Post-Processing of FDM 3D-Printed Polylactic Acid Parts by Laser Beam Cutting
Authors: Moradi Mahmoud , Karami Moghadam Mojtaba , Shamsborhan Mahmoud , Bodaghi Mahdi , Falavandi Hamid
Published: March 2020

In this paper, the post-processing of 3D-printed poly lactic acid (PLA) parts is investigated. Workpieces are manufactured by fused deposition modeling (FDM) 3D printing, while they may have defects in some areas such as edges. A post-processing is introduced here for 3D-printed samples by low power CO2 laser. The thickness of the FDM samples are 3.2 mm and printed by optimum conditions. Effects of process parameters such as focal plane position (−3.2–3.2 mm), laser power (20–40 W), and laser cutting speed (1–13 mm/s) are examined based on the design of experiments (DOE). Geometrical features of the kerf; top and bottom kerf; taper; ratio of top to the bottom kerf are considered as output responses. An analysis of the experimental results by statistical software is conducted to survey the effects of process parameters and to obtain regression equations. By optimizing of the laser cutting process; an appropriate kerf quality is obtained and also optimum input parameters are suggested. Experimental verification tests show a good agreement between empirical results and statistical predictions. The best optimum sample with 1.19 mm/s cutting speed, 36.49 W power and 0.53 mm focal plane position shows excellent physical features after the laser cutting process when 276.9 μm top and 261.5 μm bottom kerf width is cut by laser.
Effect of Concentration of Thermochromic Ink on Performance of Waterborne Finish Films for the Surface of Cunninghamia Lanceolata
Authors: Yan Xiaoxing , Chang Yijuan , Qian Xingyu
Published: March 2020

Using Cunninghamia lanceolata as a substrate, the thermochromic ink was added to the waterborne finish to test the optical properties and mechanical properties of the finish film. The results showed that the discoloration performance of the finish film with 15.0% and 30.0% of the thermochromic ink was better. The gloss of the finish film changes irregularly when the concentration increases. The finish film with a thermochromic ink concentration of 10.0% has the highest gloss, and with a concentration of 30.0% has the lowest gloss. When the thermochromic ink concentration exceeds 15.0%, the impact resistance of the finish film is slightly enhanced. The concentration is not related to the liquid resistance of the finish film. When the thermochromic ink concentration was 0–15.0%, the particle distribution uniform reunion was not much. The discoloration mechanism of discolored finish film can be considered to be as follows. After adding thermochromic ink, when the finish film temperature rises, it fades from red to colorless. When the temperature is lowered, the thermochromic ink changes to its original colour again, and the thermochromic effect is stable and sustainable. On the basis of the above results, when the thermochromic ink concentration is 15.0%, the general performance of the waterborne finish film on the Cunninghamia lanceolata surface is the best. This study provides new prospects in using thermochromic ink for waterborne finish film.
A Self-Powered Flexible Thermoelectric Sensor and Its Application on the Basis of the Hollow PEDOT:PSS Fiber
Authors: Ruan Limin , Zhao Yanjie , Chen Zihao , Zeng Wei , Wang Siliang , Liang Dong , Zhao Jinling
Published: March 2020

The thermoelectric (TE) fiber, based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), which possesses good flexibility, a low cost, good environmental stability and non-toxicity, has attracted more attention due to its promising applications in energy harvesting. This study presents a self-powered flexible sensor based on the TE properties of the hollow PEDOT:PSS fiber. The hollow structure of the fiber was synthesized using traditional wet spinning. The sensor was applied to an application for finger touch, and showed both long-term stability and good reliability towards external force. The sensor had a high scalability and was simple to develop. When figures touched the sensors, a temperature difference of 6 °C was formed between the figure and the outside environment. The summit output voltages of the sensors with 1 to 5 legs gradually increased from 90.8 μV to 404 μV. The time needed for the output voltage to reach 90% of its peak value is only 2.7 s. Five sensors of legs ranging from 1 to 5 were used to assemble the selector. This study may provide a new proposal to produce a self-powered, long-term and stable skin sensor, which is suitable for wearable devices in personal electronic fields.
Prevention of Encrustation on Ureteral Stents: Which Surface Parameters Provide Guidance for the Development of Novel Stent Materials?
Authors: Rebl Henrike , Renner Jürgen , Kram Wolfgang , Springer Armin , Fritsch Nele , Hansmann Harald , Hakenberg Oliver W. , Nebe J. Barbara
Published: March 2020

Encrustations of ureteral stents are one of the biggest problems with urological implants. Crystalline biofilms can occur alone or in combination with bacterial biofilms. To identify which surface parameters provide guidance for the development of novel stent materials, we used an in vitro encrustation system. Synthetic urine with increasing pH to simulate an infection situation was pumped over the polymer samples with adjusted flow rates at 37 °C to mimic the native body urine flow. Chemical surface features (contact angle, surface charge), as well as encrustations were characterized. The encrustations on the materials were analyzed quantitatively (dry mass) and qualitatively using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR). The aim of this comparative study was to identify crucial surface parameters that might predict the quantity and type of mineral deposits in vitro and provide guidance for the development and screening of new polymer-based biomaterials for ureteral stent design. For the first time, we could identify that, within the range of our polymers, those materials with a slight hydrophilicity and a strong negative zeta potential (around −60 mV) were most favorable for use as ureteral stent materials, as the deposition of crystalline biofilms was minimized.
Plasticization of Polylactide after Solidification: An Effectiveness and Utilization for Correct Interpretation of Thermal Properties
Authors: Safandowska Marta , Rozanski Artur , Galeski Andrzej
Published: March 2020

Polylactide/triethyl citrate (PLA/TEC) systems were prepared in two ways by introducing TEC to solidified polymer matrix (SS) and by blending in a molten state (MS) to investigate the effectiveness of the plasticization process after solidification of polylactide. The plasticization processes, independent of the way of introducing the TEC into PLA matrix, leads to systems characterized by similar stability, morphology, and properties. Some differences in mechanical properties between MS and SS systems result primarily from the difference in the degree of crystallinity/crystal thickness of the PLA matrix itself. Based on the presented results, it was concluded that the plasticization process after solidification of polylactide is an alternative to the conventional method of modification-blending in a molten state. Then, this new approach to plasticization process was utilized for the interpretation of thermal properties of PLA and PLA/TEC systems. It turned out that double melting peak observed at differential scanning calorimetry (DSC) thermograms does not result from the melting of a double population of crystals with different lamellar thickness, or the melting of both the α′ and α crystalline phase (commonly used explanations in literature), but is associated with the improvement of perfection of crystalline structure of PLA during heating process.
Surface Studies of UV Irradiated Polypropylene Films Modified with Mineral Fillers Designed as Piezoelectric Materials
Authors: Chylińska Marta , Kaczmarek Halina , Moszyński Dariusz , Królikowski Bogusław , Kowalonek Jolanta
Published: March 2020

Isotactic-polypropylene (i-PP) films with inorganic minerals such as Sillikolloid, perlite, or glass beads were prepared. The obtained polymeric films were subjected to an orientation process. Moreover, this paper includes results how the artificial accelerated weathering influences surface properties of the unoriented and oriented i-PP films with the mineral fillers. Changes in the ultraviolet (UV) treated polymeric films were studied with attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and by measuring contact angles. The results revealed that photooxidation of i-PP was more effective in the presence of the fillers and depended on the type of the filler but not on its amount. Moreover, the oriented samples experienced more effective photooxidation compared with the unoriented ones. In all studied samples the same photoproducts were detected, suggesting the same route of polymer photooxidation with and without the filler. These polymeric films were produced for potential applications in the devices in which piezoelectric effect can be used.
Fluorescent SiO2@Tb3+(PET-TEG)3Phen Hybrids as Nucleating Additive for Enhancement of Crystallinity of PET
Authors: Zhang Yanna , Wang Yao , Li Hao , Gong Xuezhong , Liu Jixian , Huang Linjun , Wang Wei , Wang Yanxin , Zhao Zhihuan , Belfiore Laurence A. , Tang Jianguo
Published: March 2020

A hybrid polymer of SiO2@Tb3+(poly(ethylene terephthalate)-tetraglycol)3 phenanthroline (SiO2@Tb3+(PET–TEG)3Phen) was synthesized by mixing of inorganic SiO2 nanoparticles with polymeric segments of PET–TEG, whereas PET–TEG was achieved through multi-step functionalization strategy. Tb3+ ions and β-diketonate ligand Phen were added in resulting material. The experimental results demonstrated that it was well blended with PET as a robust additive, and not only promoted the crystallinity, but also possessed excellent luminescence properties. An investigation of the mechanism revealed that the SiO2 nanoparticles functioned as a crystallization promotor; the Tb3+ acted as the fluorescent centre; and the PET–TEG segments played the role of linker and buffer, providing better compatibility of PET matrix with the inorganic component. This work demonstrated that hybrid polymers are appealing as multifunctional additives in the polymer processing and polymer luminescence field.
Effect of Fructose and Ascorbic Acid on the Performance of Cross-Linked Fish Gelatin Films
Authors: Guerrero Pedro , Zugasti Iraitz , Etxabide Alaitz , Bao Huynh Nguyen Duy , Trang Si Trung , Peñalba Miriam , de la Caba Koro
Published: March 2020

Gelatin was extracted from fish scales in this work, in an attempt to valorise abundant and available fishery by-products as an approach towards a more circular economy. With this strategy in mind, fish scale gelatin was used to prepare active films. In this regard, the development of advanced materials from gelatin involves its modification to enhance functional properties, particularly barrier properties, to achieve the requirements for specific value-added purposes, such as food or pharmaceutical/biomedical applications. The improvement of those functional properties can be achieved by means of chemical cross-linking processes. In this context, non-enzymatic reactions were carried out with the addition of fructose and ascorbic acid into gelatin film forming formulations, and cross-linking was induced by a heat-treatment. These cross-linking reactions resulted in higher barrier features, especially for those films prepared with ascorbic acid.
Flow-Through Catalytic Reactors Based on Metal Nanoparticles Immobilized within Porous Polymeric Gels and Surfaces/Hollows of Polymeric Membranes
Authors: Kudaibergenov Sarkyt E. , Dzhardimalieva Gulzhian I.
Published: March 2020

State-of-the-art of flow-through catalytic reactors based on metal nanoparticles immobilized within the pores of nano-, micro- and macrosized polymeric gels and in the surface or hollow of polymeric membranes is discussed in this mini-review. The unique advantages of continuous flow-through nanocatalysis over the traditional batch-type analog are high activity, selectivity, productivity, recyclability, continuous operation, and purity of reaction products etc. The methods of fabrication of polymeric carriers and immobilization technique for metal nanoparticles on the surface of porous or hollow structures are considered. Several catalytic model reactions comprising of hydrolysis, decomposition, hydrogenation, oxidation, Suzuki coupling and enzymatic reactions in the flow system are exemplified. Realization of “on-off” switching mechanism for regulation of the rate of catalytic process through controlling the mass transfers of reactants in liquid media with the help of stimuli-responsive polymers is demonstrated. Comparative analysis of the efficiency of different flow-through catalytic reactors for various reactions is also surveyed.
A Self-Adaptive Damping Control Strategy of Virtual Synchronous Generator to Improve Frequency Stability
Authors: Li Tianyang , Wen Buying , Wang Huaiyuan
Published: March 2020

In a microgrid, grid-connected inverters, as the interface between the distributed power supply and grid, cannot provide inertia support for the system. The control strategy of virtual synchronous generator (VSG) based on grid-connected inverters can enhance the stability of system frequency. In order to make the frequency response that has a smaller overshoot and a shorter settling time, a self-adaptive damping control strategy based on the relationship between the damping and the maximum frequency deviation for microgrid VSG is presented. The small-signal mathematical model of VSG is established, and the range of the damping coefficient is determined. Finally, simulation experiments are carried out with MATLAB/Simulink, and the effectiveness of the proposed control strategy is verified by comparing it with various damping control methods.
NOAA Operational Microwave Sounding Radiometer Data Quality Monitoring and Anomaly Assessment Using COSMIC GNSS Radio-Occultation Soundings
Authors: Iacovazzi Robbie , Lin Lin , Sun Ninghai , Liu Quanhua
Published: March 2020

National Oceanic and Atmospheric Administration (NOAA) operational Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit-A (AMSU-A) data used in numerical weather prediction and climate analysis are essential to protect life and property and maintain safe and efficient commerce. Routine data quality monitoring and anomaly assessment is important to sustain data effectiveness. One valuable parameter used to monitor microwave sounder data quality is the antenna temperature (Ta) difference (O-B) computed between direct instrument Ta measurements and forward radiative transfer model (RTM) brightness temperature (Tb) simulations. This requires microwave radiometer data to be collocated with atmospheric temperature and moisture sounding profiles, so that representative boundary conditions are used to produce the RTM-simulated Tb values. In this study, Constellation Observing System for Meteorology, Ionosphere, and Climate/Formosa Satellite Mission 3 (COSMIC) Global Navigation Satellite System (GNSS) Radio Occultation (RO) soundings over the ocean and equatorward of 60° latitude are used as input to the Community RTM (CRTM) to generate simulated NOAA-18, NOAA-19, Metop-A, and Metop-B AMSU-A and S-NPP and NOAA-20 ATMS Tb values. These simulated Tb values, together with observed Ta values that are nearly simultaneous in space and time, are used to compute Ta O-B statistics on monthly time scales for each instrument. In addition, the CRTM-simulated Tb values based on the COSMIC GNSS RO soundings can be used as a transfer standard to inter-compare Ta values from different microwave radiometer makes and models that have the same bands. For example, monthly Ta O-B statistics for NOAA-18 AMSU-A Channels 4–12 and NOAA-20 ATMS Channels 5–13 can be differenced to estimate the “double-difference” Ta biases between these two instruments for the corresponding frequency bands. This study reveals that the GNSS RO soundings are critical to monitoring and trending individual instrument O-B Ta biases and inter-instrument “double-difference” Ta biases and also to estimate impacts of some sensor anomalies on instrument Ta values.
Synergistic Use of Multi-Temporal RADARSAT-2 and VENµS Data for Crop Classification Based on 1D Convolutional Neural Network
Authors: Liao Chunhua , Wang Jinfei , Xie Qinghua , Baz Ayman Al , Huang Xiaodong , Shang Jiali , He Yongjun
Published: March 2020

Annual crop inventory information is important for many agriculture applications and government statistics. The synergistic use of multi-temporal polarimetric synthetic aperture radar (SAR) and available multispectral remote sensing data can reduce the temporal gaps and provide the spectral and polarimetric information of the crops, which is effective for crop classification in areas with frequent cloud interference. The main objectives of this study are to develop a deep learning model to map agricultural areas using multi-temporal full polarimetric SAR and multi-spectral remote sensing data, and to evaluate the influence of different input features on the performance of deep learning methods in crop classification. In this study, a one-dimensional convolutional neural network (Conv1D) was proposed and tested on multi-temporal RADARSAT-2 and VENµS data for crop classification. Compared with the Multi-Layer Perceptron (MLP), Recurrent Neural Network (RNN) and non-deep learning methods including XGBoost, Random Forest (RF), and Support Vector Machina (SVM), the Conv1D performed the best when the multi-temporal RADARSAT-2 data (Pauli decomposition or coherency matrix) and VENµS multispectral data were fused by the Minimum Noise Fraction (MNF) transformation. The Pauli decomposition and coherency matrix gave similar overall accuracy (OA) for Conv1D when fused with the VENµS data by the MNF transformation (OA = 96.65 ± 1.03% and 96.72 ± 0.77%). The MNF transformation improved the OA and F-score for most classes when Conv1D was used. The results reveal that the coherency matrix has a great potential in crop classification and the MNF transformation of multi-temporal RADARSAT-2 and VENµS data can enhance the performance of Conv1D.