bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromagnetic Pulse Welding of Tubular Products: Influence of Process Parameters and Workpiece Geometry on the Joint Characteristics and Investigation of Suitable Support Systems for the Target Tube
Authors: Faes Koen , Kwee Irene , De Waele Wim
Published: May 2019

In this experimental research, copper to steel tubular joints were produced by electromagnetic pulse welding. In a first phase, non-supported target tubes were used in order to investigate the influence of the workpiece geometry on the weld formation and joint characteristics. For this purpose, different joint configurations were used, more specific the tube-to-rod and the tube-to-tube configurations, with target workpieces with different diameters and wall thicknesses. Also, some preliminary investigations were performed to examine a support method for the target tubes. In a second phase, suitable support systems for the target tubes were identified. The resulting welds were evaluated in terms of their leak tightness, weld length and deformation of the target tube. It can be concluded that polyurethane (PU), polymethylmethacrylaat (PMMA), polyamide (PA6.6) and steel rods can be considered as valuable internal supports leading to high-quality welds and a sufficient cross-sectional area after welding. Welds with a steel bar support exhibit the highest cross-sectional area after welding, but at the same time the obtained weld quality is lower compared to welds with a PA6.6 or PMMA support. In contrast, welds with a PA6.6 or PU support show the highest weld quality, but also have a lower cross-sectional area after welding compared to steel internal supports.
Innovative Alcoholic Drinks Obtained by Co-Fermenting Grape Must and Fruit Juice
Authors: Fracassetti Daniela , Bottelli Paolo , Corona Onofrio , Foschino Roberto , Vigentini Ileana
Published: May 2019

In this study, Cabernet Sauvignon and Chardonnay musts, and fruit juices from cherry, kiwi, peach, and strawberry were co-fermented with Saccharomyces cerevisiae EC1118 and Torulaspora delbrueckii UMY196 at two different proportions (80:20 (v/v) and 60:40 (v/v)). The most pleasant fruit-based drink was obtained with Cabernet Sauvignon must and kiwi juice in a proportion of 60:40 and fermented with T. delbrueckii. This beverage was produced in higher volume to simulate a scale-up, and the aromatic profile, sensory description, and consumer acceptability were determined. The most powerful odorants of the kiwi-based drink were ethyl octanoate, phenylethanal, ethyl hexanoate, vinyl-guaiacol, benzaldehyde, and nonanal, for which the odor activity values were 21.1, 3.3, 2.6, 2.2, 1.9, and 1.6, respectively. These findings were in accordance with the sensory analysis, since the emerged descriptors were fruity (ethyl octanoate), honey and floral (phenylethanal), apple and peach (ethyl hexanoate), and citrus (nonanal). The consumers judged the kiwi-based drink acceptable (67%) and 39% of them would buy it. The reliable fermentation of a grape must/fruit juice was demonstrated. The kiwi-based drink represents an innovative and pleasant beverage with a positive impact on sustainability as its production can limit the loss of fresh fruits, as well as contribute to the enological field.
Development of a Spherical Model with a 3D Microchannel: An Application to Glaucoma Surgery
Authors: Gallab Mahmoud , Omata Seiji , Harada Kanako , Mitsuishi Mamoru , Sugimoto Koichiro , Ueta Takashi , Totsuka Kiyohito , Araki Fumiyuki , Takao Muneyuki , Aihara Makoto , Arai Fumihito
Published: May 2019

Three-dimensional (3D) microfluidic channels, which simulate human tissues such as blood vessels, are useful in surgical simulator models for evaluating surgical devices and training novice surgeons. However, animal models and current artificial models do not sufficiently mimic the anatomical and mechanical properties of human tissues. Therefore, we established a novel fabrication method to fabricate an eye model for use as a surgical simulator. For the glaucoma surgery task, the eye model consists of a sclera with a clear cornea; a 3D microchannel with a width of 200–500 µm, representing the Schlemm’s canal (SC); and a thin membrane with a thickness of 40–132 µm, representing the trabecular meshwork (TM). The sclera model with a clear cornea and SC was fabricated by 3D molding. Blow molding was used to fabricate the TM to cover the inner surface of the sclera part. Soft materials with controllable mechanical behaviors were used to fabricate the sclera and TM parts to mimic the mechanical properties of human tissues. Additionally, to simulate the surgery with constraints similar to those in a real operation, the eye model was installed on a skull platform. Therefore, in this paper, we propose an integration method for fabricating an eye model that has a 3D microchannel representing the SC and a membrane representing the TM, to develop a glaucoma model for training novice surgeons.
Influence of MgO on Low Temperature Reduction and Mineralogical Changes of Sinter in Simulated COREX Shaft Furnace Reducing Conditions
Authors: Zhu Deqing , Chou Jianlei , Shi Benjing , Pan Jian
Published: May 2019

COREX (Coal-Reduction-Extreme) smelting reduction process provides a sustainable developing way for ironmaking industry, but the sources of iron ore materials restrict its development in China. Meanwhile, the application of sinter, which is marked by low manufacture cost and overcapacity in China, to COREX furnace faced proportion limitation due to its worse low temperature reduction degradation performance. This work explored the influence of MgO content on the low-temperature (550 °C) reduction of sinter in reducing conditions simulating COREX shaft furnace. The mineralogical change of sinter containing different content of MgO before and after reduction was analyzed by X-ray diffraction (XRD), optical microscopy, and scanning electron microscopy for revealing the action mechanism of MgO on the low-temperature-reduction of sinter. The results show that increasing MgO (1.36–3.10%) improved the low temperature reduction degradation performance of sinter, and decreased its reduction degree and reduction rate at low temperature. More MgO the sinter contained, less Fe2O3 and SFCA was observed in sinter. Meantime, less Fe2O3 was reduced and the generation of innerstress was restrained during reduction process. The improved RDI (reduction degradation index) in COREX process of sinter by increasing MgO content is a comprehensive result of lowering strength and inhibiting probable reduction of sinter.
Consideration of Influential Factors on Bioleaching of Gold Ore Using Iodide-Oxidizing Bacteria
Authors: Khaing San Yee , Sugai Yuichi , Sasaki Kyuro , Tun Myo Min
Published: May 2019

Iodide-oxidizing bacteria (IOB) oxidize iodide into iodine and triiodide which can be utilized for gold dissolution. IOB can be therefore useful for gold leaching. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the performance of the gold dissolution through the experiments incubating IOB in the culture medium containing the marine broth, potassium iodide and gold ore. The minimum necessary concentration of marine broth and potassium iodide for the complete gold dissolution were determined to be 18.7 g/L and 10.9 g/L respectively. The initial bacterial cell number had no effect on gold dissolution when it was 1 × 104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 °C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under static conditions. Shaking incubation effectively shortened the contact time compared to the static incubation. According to the pH and redox potential of the culture solution, the stable gold complex in the culture solution of this study could be designated as gold (I) diiodide.
Deep-sea Hydrothermal Vent Bacteria as a Source of Glycosaminoglycan-Mimetic Exopolysaccharides
Authors: Zykwinska Agata , Marchand Laëtitia , Bonnetot Sandrine , Sinquin Corinne , Colliec-Jouault Sylvia , Delbarre-Ladrat Christine
Published: May 2019

Bacteria have developed a unique strategy to survive in extreme environmental conditions through the synthesis of an extracellular polymeric matrix conferring upon the cells a protective microenvironment. The main structural component of this complex network constitutes high-molecular weight hydrophilic macromolecules, namely exopolysaccharides (EPS). EPS composition with the presence of particular chemical features may closely be related to the specific conditions in which bacteria evolve. Deep-sea hydrothermal vent bacteria have already been shown to produce EPS rich in hexosamines and uronic acids, frequently bearing some sulfate groups. Such a particular composition ensures interesting functional properties, including biological activities mimicking those known for glycosaminoglycans (GAG). The aim of the present study was to go further into the exploration of the deep-sea hydrothermal vent IFREMER (French Research Institute for Exploitation of the Sea) collection of bacteria to discover new strains able to excrete EPS endowed with GAG-like structural features. After the screening of our whole collection containing 692 strains, 38 bacteria have been selected for EPS production at the laboratory scale. EPS-producing strains were identified according to 16S rDNA phylogeny. Chemical characterization of the obtained EPS highlighted their high chemical diversity with the presence of atypical compositional patterns. These EPS constitute potential bioactives for a number of biomedical applications, including regenerative medicines and cancer treatment.
Evaluating the In Vivo Specificity of [18F]UCB-H for the SV2A Protein, Compared with SV2B and SV2C in Rats Using microPET
Authors: Serrano Maria Elisa , Becker Guillaume , Bahri Mohamed Ali , Seret Alain , Mestdagh Nathalie , Mercier Joël , Mievis Frédéric , Giacomelli Fabrice , Lemaire Christian , Salmon Eric , Luxen André , Plenevaux Alain
Published: May 2019

The synaptic vesicle protein 2 (SV2) is involved in synaptic vesicle trafficking. The SV2A isoform is the most studied and its implication in epilepsy therapy led to the development of the first SV2A PET radiotracer [18F]UCB-H. The objective of this study was to evaluate in vivo, using microPET in rats, the specificity of [18F]UCB-H for SV2 isoform A in comparison with the other two isoforms (B and C) through a blocking assay. Twenty Sprague Dawley rats were pre-treated either with the vehicle, or with specific competitors against SV2A (levetiracetam), SV2B (UCB5203) and SV2C (UCB0949). The distribution volume (Vt, Logan plot, t* 15 min) was obtained with a population-based input function. The Vt analysis for the entire brain showed statistically significant differences between the levetiracetam group and the other groups (p < 0.001), but also between the vehicle and the SV2B group (p < 0.05). An in-depth Vt analysis conducted for eight relevant brain structures confirmed the statistically significant differences between the levetiracetam group and the other groups (p < 0.001) and highlighted the superior and the inferior colliculi along with the cortex as regions also displaying statistically significant differences between the vehicle and SV2B groups (p < 0.05). These results emphasize the in vivo specificity of [18F]UCB-H for SV2A against SV2B and SV2C, confirming that [18F]UCB-H is a suitable radiotracer for in vivo imaging of the SV2A proteins with PET.
Enhancement of Single-Photon Emission Rate from InGaAs/GaAs Quantum-Dot/Nanowire Heterostructure by Wire-Groove Nanocavity
Authors: Wei Wei , Yan Xin , Liu Jie , Shen Bing , Luo Wei , Ma Xiaofeng , Zhang Xia
Published: May 2019

Spontaneous emission of luminescent material is strongly dependent on the surrounding electromagnetic environment. To enhance the emission rate of a single-photon emitter, we proposed a wire-groove resonant nanocavity around the single-photon emitter. An InGaAs quantum dot embedded in a GaAs nanowire was employed as a site-control single-photon emitter. The nanoscale cavity built by a wire-groove perpendicular to the quantum dot with an extremely narrow width of 10 nm exhibited an extremely small volume of 10 × 40 × 259 nm3. Theoretical analysis showed that the emission rate of the quantum dot was dramatically enhanced by 617x due to the Purcell effect induced by the wire-groove cavity. A fast single-photon emitter with a rate of 50.2 GHz can be obtained that speeds up the data rate of the single-photon emitter. This ultrafast single-photon source would be of great significance in quantum information systems and networks.
High Catalytic Performance of Mn-Doped Ce-Zr Catalysts for Chlorobenzene Elimination
Authors: Zhu Lei , Li Xi , Liu Zhiying , Yao Lin , Yu Peng , Wei Ping , Xu Yanhua , Jiang Xingmao
Published: May 2019

Mn-Ce-Zr-O catalysts doped with varying Mn content were prepared and assessed for the catalytic combustion of chlorobenzene (CB). Nanosized MCZ-0.67 catalyst with amorphous phase exhibited a high and stable catalytic activity among the studied catalysts, achieving 90% CB conversion at 226 °C and withstanding stability tests, including time-based stability and the successive influence of various operating conditions. Meanwhile, the MCZ-0.67 catalyst used showed good recyclability by calcination in air. Characterization results suggested that Mn doping played a dominant role in improving the catalytic performance, resulting in larger surface area, better redox properties and greater amounts of surface active oxygen. In addition, the introduction of Zr was also indispensable for maintaining the good catalytic performance of catalysts. Finally, trace amounts of polychlorinated by-products during CB oxidation were monitored and the oxidation process was discussed.
Laser-Synthesized SERS Substrates as Sensors toward Therapeutic Drug Monitoring
Authors: Tommasini Matteo , Zanchi Chiara , Lucotti Andrea , Bombelli Alessandro , Villa Nicolò S. , Casazza Marina , Ciusani Emilio , de Grazia Ugo , Santoro Marco , Fazio Enza , Neri Fortunato , Trusso Sebastiano , Ossi Paolo M.
Published: May 2019

The synthesis by pulsed laser ablation and the characterization of both the surface nanostructure and the optical properties of noble metal nanoparticle-based substrates used in Surface Enhanced Raman Spectroscopy are discussed with reference to application in the detection of anti-epileptic drugs. Results on two representative drugs, namely Carbamazepine and Perampanel, are critically addressed.
Small-Angle Scattering as a Structural Probe for Nucleic Acid Nanoparticles (NANPs) in a Dynamic Solution Environment
Authors: Oliver Ryan C. , Rolband Lewis A. , Hutchinson-Lundy Alanna M. , Afonin Kirill A. , Krueger Joanna K.
Published: May 2019

Nucleic acid-based technologies are an emerging research focus area for pharmacological and biological studies because they are biocompatible and can be designed to produce a variety of scaffolds at the nanometer scale. The use of nucleic acids (ribonucleic acid (RNA) and/or deoxyribonucleic acid (DNA)) as building materials in programming the assemblies and their further functionalization has recently established a new exciting field of RNA and DNA nanotechnology, which have both already produced a variety of different functional nanostructures and nanodevices. It is evident that the resultant architectures require detailed structural and functional characterization and that a variety of technical approaches must be employed to promote the development of the emerging fields. Small-angle X-ray and neutron scattering (SAS) are structural characterization techniques that are well placed to determine the conformation of nucleic acid nanoparticles (NANPs) under varying solution conditions, thus allowing for the optimization of their design. SAS experiments provide information on the overall shapes and particle dimensions of macromolecules and are ideal for following conformational changes of the molecular ensemble as it behaves in solution. In addition, the inherent differences in the neutron scattering of nucleic acids, lipids, and proteins, as well as the different neutron scattering properties of the isotopes of hydrogen, combined with the ability to uniformly label biological macromolecules with deuterium, allow one to characterize the conformations and relative dispositions of the individual components within an assembly of biomolecules. This article will review the application of SAS methods and provide a summary of their successful utilization in the emerging field of NANP technology to date, as well as share our vision on its use in complementing a broad suite of structural characterization tools with some simulated results that have never been shared before.
Over Restriction of Dietary Protein Allowance: The Importance of Ongoing Reassessment of Natural Protein Tolerance in Phenylketonuria
Authors: Pinto Alex , Ferreira Almeida Manuela , MacDonald Anita , Cristina Ramos Paula , Rocha Sara , Guimas Arlindo , Ribeiro Rosa , Martins Esmeralda , Bandeira Anabela , Jackson Richard , van Spronsen Francjan , Payne Anne , César Rocha Júlio
Published: May 2019

Phenylalanine (Phe) tolerance is highly variable in phenylketonuria (PKU) and rarely described in patients aged ≥12 years. Patients ≥12 years of age with PKU were systematically challenged with additional natural protein (NP) if blood Phe levels remained below 480 µmol/L (i.e., upper target blood Phe level for patients aged ≥12 years using Portuguese PKU guidelines). In PKU patients, NP tolerance was calculated at baseline and a median of 6 months after systematic challenge with NP whilst patients were maintaining a blood Phe ≤480 μmol/L. Anthropometry was assessed at both times. Routine blood Phe levels were collected. We studied 40 well-controlled PKU patients (10 hyperphenylalaninemia (HPA), 23 mild and 7 classic PKU), on a low-Phe diet with a mean age of 17 years (12–29 years). Median daily NP intake significantly increased between assessments (35 vs. 40 g/day, p = 0.01). Twenty-six patients (65%) were able to increase their median NP intake by a median 12 g/day (2–42 g)/day and still maintain blood Phe within target range. Out of the previous 26 patients, 20 (77%) (8 HPA, 11 mild and 1 classical PKU) increased NP from animal sources (e.g., dairy products, fish and meat) and 6 patients (23%) (3 mild and 3 classical PKU) from plant foods (bread, pasta, potatoes). Median protein equivalent intake from Phe-free/low-Phe protein substitute decreased (0.82 vs. 0.75 g/kg, p = 0.01), while median blood Phe levels remained unchanged (279 vs. 288 μmol/L, p = 0.06). Almost two-thirds of patients with PKU tolerated additional NP when challenged and still maintained blood Phe within the national target range. This suggests that some patients with PKU treated by a low-Phe diet only may over restrict their NP intake. In order to minimise the burden of treatment and optimise NP intake, it is important to challenge with additional NP at periodic intervals.
Laminaria japonica Extract Enhances Intestinal Barrier Function by Altering Inflammatory Response and Tight Junction-Related Protein in Lipopolysaccharide-Stimulated Caco-2 Cells
Authors: Yang Hyo-Seon , Haj Fawaz G , Lee Myoungsook , Kang Inhae , Zhang Guiguo , Lee Yunkyoung
Published: May 2019

In the normal physiological state, intestinal epithelial cells act as a defensive frontline of host mucosal immunity to tolerate constant exposure to external stimuli. In this study, we investigated the potential anti-inflammatory and gut permeability protective effects of Laminaria japonica (LJ) water extract (LJE) and three types of fermented Laminaria japonica water extracts (LJE-F1, LJE-F2, and LJE-F3) in lipopolysaccharide (LPS)-stimulated Caco-2, human intestinal epithelial cells. All four extracts significantly decreased the production of nitric oxide and interleukin-6 induced by LPS stimulus. In addition, LJE and the three types of LJE-Fs also inhibited LPS-induced loss of monolayer permeability, as assessed by changes in transepithelial electrical resistance. All four LJ extracts significantly prevented the inhibition of the protein levels of occludin, whereas LJE, LJE-F1, and LJE-F3 significantly attenuated the reduction in phosphorylation of adenosine monophosphate-activated protein kinase compared with the LPS-treated group in Caco-2 cells. In conclusion, LJE and its fermented water extracts appear to have potential gut health-promoting effects by reducing inflammation and partially regulating the tight junction-related proteins in human intestinal epithelial cells. Thus, additional studies are warranted to evaluate Laminaria japonica as a therapeutic agent for inflammatory bowel diseases.
Putative Periodontal Pathogens, Filifactor alocis and Peptoanaerobacter stomatis, Induce Differential Cytokine and Chemokine Production by Human Neutrophils
Authors: Vashishta Aruna , Jimenez-Flores Emeri , Klaes Christopher , Tian Shifu , Miralda Irina , Lamont Richard , Uriarte Silvia
Published: May 2019

Periodontitis is a highly prevalent infectious disease that affects ~ 50% of the adults in the USA alone. Two Gram-positive anaerobic oral bacteria, Filifactor alocis and Peptoanaerobacter stomatis, have emerged as important periodontal pathogens. Neutrophils are a major component of the innate host response in the gingival tissue, and the contribution of neutrophil-derived cytokines and chemokines plays a central role in disease progression. The pattern of cytokines and chemokines released by human neutrophils upon stimulation with newly appreciated periodontal bacteria compared to the keystone oral pathogen Porphyromonas gingivalis was investigated. Our results showed that both F. alocis and P. stomatis triggered TLR2/6 activation. F. alocis induced significant changes in gene expression of cytokines and chemokines in human neutrophils compared to unstimulated cells. However, except for IL-1ra, neutrophils released lower levels of cytokines and chemokines in response to F. alocis compared to P. stomatis. Furthermore, bacteria-free conditioned supernatant collected from neutrophils challenged with P. stomatis, but not from P. gingivalis or F. alocis, was chemotactic towards both neutrophils and monocytes. Elucidating stimuli-specific modulation of human neutrophil effector functions in the context of dysbiotic microbial community constituents provides valuable information for understanding the pathogenesis of periodontal diseases.
Targeting the Serine Pathway: A Promising Approach against Tuberculosis?
Authors: Haufroid Marie , Wouters Johan
Published: May 2019

Tuberculosis is still the leading cause of death by a single infectious agent. Effective chemotherapy has been used and improved since the 1950s, but strains resistant to this therapy and most antibacterial drugs on the market are emerging. Only 10 new drugs are in clinical trials, and two of them have already demonstrated resistance. This paper gives an overview of current treatment options against tuberculosis and points out a promising approach of discovering new effective drugs. The serine production pathway is composed of three enzymes (SerA1, SerC and SerB2), which are considered essential for bacterial growth, and all of them are considered as a therapeutic drug target. Their crystal structure are described and essential regulatory domains pointed out. Sequence alignment with similar enzymes in other host would help to identify key residues to target in order to achieve selective inhibition. Currently, only inhibitors of SerB2 are described in the literature. However, inhibitors of human enzymes are discussed, and could be used as a good starting point for a drug discovery program. The aim of this paper is to give some guidance for the design of new hits for every enzyme in this pathway.
Exploring Light-Sensitive Nanocarriers for Simultaneous Triggered Antibiotic Release and Disruption of Biofilms Upon Generation of Laser-Induced Vapor Nanobubbles
Authors: Teirlinck Eline , Barras Alexandre , Liu Jing , Fraire Juan C. , Lajunen Tatu , Xiong Ranhua , Forier Katrien , Li Chengnan , Urtti Arto , Boukherroub Rabah , Szunerits Sabine , De Smedt Stefaan C. , Coenye Tom , Braeckmans Kevin
Published: May 2019

Impaired penetration of antibiotics through bacterial biofilms is one of the reasons for failure of antimicrobial therapy. Hindered drug diffusion is caused on the one hand by interactions with the sticky biofilm matrix and on the other hand by the fact that bacterial cells are organized in densely packed clusters of cells. Binding interactions with the biofilm matrix can be avoided by encapsulating the antibiotics into nanocarriers, while interfering with the integrity of the dense cell clusters can enhance drug transport deep into the biofilm. Vapor nanobubbles (VNB), generated from laser irradiated nanoparticles, are a recently reported effective way to loosen up the biofilm structure in order to enhance drug transport and efficacy. In the present study, we explored if the disruptive force of VNB can be used simultaneously to interfere with the biofilm structure and trigger antibiotic release from light-responsive nanocarriers. The antibiotic tobramycin was incorporated in two types of light-responsive nanocarriers—liposomes functionalized with gold nanoparticles (Lip-AuNP) and graphene quantum dots (GQD)—and their efficacy was evaluated on Pseudomonas aeruginosa biofilms. Even though the anti-biofilm efficacy of tobramycin was improved by liposomal encapsulation, electrostatic functionalization with 70 nm AuNP unfortunately resulted in premature leakage of tobramycin in a matter of hours. Laser-irradiation consequently did not further improve P. aeruginosa biofilm eradication. Adsorption of tobramycin to GQD, on the other hand, did result in a stable formulation with high encapsulation efficiency, without burst release of tobramycin from the nanocarriers. However, even though laser-induced VNB formation from GQD resulted in biofilm disruption, an enhanced anti-biofilm effect was not achieved due to tobramycin not being efficiently released from GQD. Even though this study was unsuccessful in designing suitable nanocarriers for simultaneous biofilm disruption and light-triggered release of tobramycin, it provides insights into the difficulties and challenges that need to be considered for future developments in this regard.
Crystallization Tendency of Pharmaceutical Glasses: Relevance to Compound Properties, Impact of Formulation Process, and Implications for Design of Amorphous Solid Dispersions
Authors: Kawakami Kohsaku
Published: May 2019

Amorphous solid dispersions (ASDs) are important formulation strategies for improving the dissolution process and oral bioavailability of poorly soluble drugs. Physical stability of a candidate drug must be clearly understood to design ASDs with superior properties. The crystallization tendency of small organics is frequently estimated by applying rapid cooling or a cooling/reheating cycle to their melt using differential scanning calorimetry. The crystallization tendency determined in this way does not directly correlate with the physical stability during isothermal storage, which is of great interest to pharmaceutical researchers. Nevertheless, it provides important insights into strategy for the formulation design and the crystallization mechanism of the drug molecules. The initiation time for isothermal crystallization can be explained using the ratio of the glass transition and storage temperatures (Tg/T). Although some formulation processes such as milling and compaction can enhance nucleation, the Tg/T ratio still works for roughly predicting the crystallization behavior. Thus, design of accelerated physical stability test may be possible for ASDs. The crystallization tendency during the formulation process and the supersaturation ability of ASDs may also be related to the crystallization tendency determined by thermal analysis. In this review, the assessment of the crystallization tendency of pharmaceutical glasses and its relevance to developmental studies of ASDs are discussed.
Sodium Hyaluronate Nanocomposite Respirable Microparticles to Tackle Antibiotic Resistance with Potential Application in Treatment of Mycobacterial Pulmonary Infections
Authors: Rossi Irene , Buttini Francesca , Sonvico Fabio , Affaticati Filippo , Martinelli Francesco , Annunziato Giannamaria , Machado Diana , Viveiros Miguel , Pieroni Marco , Bettini Ruggero
Published: May 2019

Tuberculosis resistant cases have been estimated to grow every year. Besides Mycobacterium tuberculosis, other mycobacterial species are responsible for an increasing number of difficult-to-treat infections. To increase efficacy of pulmonary treatment of mycobacterial infections an inhalable antibiotic powder targeting infected alveolar macrophages (AMs) and including an efflux pump inhibitor was developed. Low molecular weight sodium hyaluronate sub-micron particles were efficiently loaded with rifampicin, isoniazid and verapamil, and transformed in highly respirable microparticles (mean volume diameter: 1 μm) by spray drying. These particles were able to regenerate their original size upon contact with aqueous environment with mechanical stirring or sonication. The in vitro drugs release profile from the powder was characterized by a slow release rate, favorable to maintain a high drug level inside AMs. In vitro antimicrobial activity and ex vivo macrophage infection assays employing susceptible and drug resistant strains were carried out. No significant differences were observed when the powder, which did not compromise the AMs viability after a five-day exposure, was compared to the same formulation without verapamil. However, both preparations achieved more than 80% reduction in bacterial viability irrespective of the drug resistance profile. This approach can be considered appropriate to treat mycobacterial respiratory infections, regardless the level of drug resistance.
Advantages and Limitations of Integrated Flagellin Adjuvants for HIV-Based Nanoparticle B-Cell Vaccines
Authors: Barnowski Cornelia , Kadzioch Nicole , Damm Dominik , Yan Huimin , Temchura Vladimir
Published: May 2019

The great advantage of virus-like particle (VLP) nano-vaccines is their structural identity to wild-type viruses, ensuring that antigen-specific B-cells encounter viral proteins in their natural conformation. “Wild-type” viral nanoparticles can be further genetically or biochemically functionalized with biomolecules (antigens and adjuvants). Flagellin is a potent inducer of innate immunity and it has demonstrated adjuvant effectiveness due to its affinity for toll-like receptor 5 (TLR5). In contrast to most TLR ligands, flagellin is a protein and can induce an immune response against itself. To avoid side-effects, we incorporated a less inflammatory and less immunogenic form of flagellin as an adjuvant into HIV-based nanoparticle B-cell-targeting vaccines that display either the HIV-1 envelope protein (Env) or a model antigen, hen egg lysozyme (HEL). While flagellin significantly enhanced HEL-specific IgG responses, anti-Env antibody responses were suppressed. We demonstrated that flagellin did not activate B-cells directly in vitro, but might compete for CD4+ T-cell help in vivo. Therefore, we hypothesize that in the context of VLP-based B-cell nano-vaccines, flagellin serves as an antigen itself and may outcompete a less immunogenic antigen with its antibody response. In contrast, in combination with a strong immunogen, the adjuvant activity of flagellin may dominate over its immunogenicity.
Wound Healing Property of Curcuminoids as a Microcapsule-Incorporated Cream
Authors: Ang Lee , Darwis Yusrida , Koh Rhun , Gah Leong Kenny , Yew Mei , Por Lip , Yam Mun
Published: May 2019

Curcuminoids have been used for the management of burns and wound healing in traditional Chinese medicine practices but the wide application of curcuminoids as a healing agent for wounds has always been a known problem due to their poor solubility, bioavailability, colour staining properties, as well as due to their intense photosensitivity and the need for further formulation approaches to maximise their various properties in order for them to considerably contribute towards the wound healing process. In the present study, a complex coacervation microencapsulation was used to encapsulate curcuminoids using gelatin B and chitosan. This study also focused on studying and confirming the potential of curcuminoids in a microencapsulated form as a wound healing agent. The potential of curcuminoids for wound management was evaluated using an in vitro human keratinocyte cell (HaCaT) model and the in vivo heater-inflicted burn wound model, providing evidence that the antioxidant activities of both forms of curcuminoids, encapsulated or not, are higher than those of butylated hydroxyanisole and butylated hydroxytoluene in trolox equivalent antioxidant capacity (TEAC) and (2,2-diphenyl-1-picryl-hydrazyl-hydrate) (DPPH) studies. However, curcuminoids did not have much impact towards cell migration and proliferation in comparison with the negative control in the in vitro HaCaT study. The micoencapsulation formulation was shown to significantly influence wound healing in terms of increasing the wound contraction rate, hydroxyproline synthesis, and greater epithelialisation, which in turn provides strong justification for the incorporation of the microencapsulated formulation of curcuminoids as a topical treatment for burns and wound healing management as it has the potential to act as a crucial wound healing agent in healthcare settings.
Description of the Droplet Size Evolution in Flowing Immiscible Polymer Blends
Authors: Fortelný Ivan , Jůza Josef
Published: May 2019

Control of the phase structure evolution in flowing immiscible polymer blends during their mixing and processing is fundamental for tailoring of their performance. This review summarizes present state of understanding and predictability of the phase structure evolution in flowing immiscible polymer blends with dispersed structure. Results of the studies of the droplet breakup in flow, important for determination of the droplet breakup frequency and of the size distribution of the daughter droplets, are reviewed. Theories of the flow-induced coalescence providing equations for collision efficiency are discussed. Approximate analytic expressions reliably describing dependence of the collision efficiency on system parameters are presented. Available theories describing the competition between the droplet breakup and coalescence in flow are summarized and approximations used in their derivation are discussed. Problems with applicability of available theories on prediction of the droplet size evolution during mixing and processing of immiscible polymer blends, which have not been broadly discussed so far, are addressed.
Facile Fabrication of Environmentally-Friendly Hydroxyl-Functionalized Multiwalled Carbon Nanotubes/Soy Oil-Based Polyurethane Nanocomposite Bioplastics with Enhanced Mechanical, Thermal, and Electrical Conductivity Properties
Authors: Luo Xiaogang , Yu Zengcheng , Cai Yixin , Wu Qiangxian , Zeng Jian
Published: May 2019

It is challenging to prepare polyurethane bioplastics from renewable resources in a sustainable world. In this work, polyurethane nanocomposite bioplastics are fabricated by blending up to 80 wt % of soy-based polyol and petrochemical polyol with hydroxyl-functionalized multiwalled carbon nanotubes (MWCNTs-OH). The scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR) analyses reveal homogeneous dispersion of the MWCNTs-OH in the matrix, as well as interaction or reaction of MWCNTs-OH with the matrix or polymeric methylene diphenyl diisocyanate (pMDI) in forming the organic–inorganic hybrid bioplastic with a three-dimensional (3D) macromolecule network structure. Mechanical properties and electrical conductivity are remarkably enhanced with the increase of the multiwalled carbon nanotube (MWCNTs) loading. Dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) results show that the bioplastics with MWCNTs-OH have a better thermal stability compared with the bioplastics without MWCNTs-OH. The composition of the nanocomposites, which defines the characteristics of the material and its thermal and electrical conductivity properties, can be precisely controlled by simply varying the concentration of MWCNTs-OH in the polyol mixture solution.
Controlling the Performance of Polymer Lasers via the Cavity Coupling
Authors: Zhang Shuai , Tong Junhua , Chen Chao , Cao Fengzhao , Liang Chengbin , Song Yanrong , Zhai Tianrui , Zhang Xinping
Published: May 2019

The polarization and threshold of distributed feedback (DFB) polymer lasers were controlled by adjusting the cavity coupling. The cavity of DFB polymer lasers consisted of two gratings, which was fabricated by a two-beam multi-exposure holographic technique. The coupling strength of the cavity modes was tuned by changing the angle between the two gratings. The threshold of the polymer lasers decreased with reducing the coupling strength of the cavity modes. A minimum threshold was observed at the lowest coupling strength. Moreover, the azimuthally polarized output of the polymer lasers was modified by changing the cavity coupling. These results may provide additional perspectives to improve the performance of DFB polymer lasers.
Synthesis of Thermo-Responsive Block-Graft Copolymer Based on PCL and PEG Analogs, and Preparation of Hydrogel via Click Chemistry
Authors: Shang Pei , Wu Jie , Shi Xiaoyu , Wang Zhidan , Song Fei , Liu Shouxin
Published: May 2019

Thermo-responsive cross-linkable mPEG-b-[PCL-g-(MEO2MA-co-OEGMA)]-b-mPEG was synthesized by ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). Then, the cross-linkable block-graft copolymer was used to prepare hydrogel via a copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition reaction. The chemical structure and composition of copolymer were characterized by proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behaviors of the copolymer in aqueous solution were studied by UV spectrophotometer, fluorescence probes, the surface tension method, dynamic light scattering, and transmission electron microscopy. The results proved that the copolymer has excellent solubility and better temperature response. The three-dimensional network structure of the gels, observed by scanning electron microscopy at different temperatures, indicated that the gels have temperature response.
Poly(arylene ether nitrile) Composites with Surface-Hydroxylated Calcium Copper Titanate Particles for High-Temperature-Resistant Dielectric Applications
Authors: Yang Junyi , Tang Zili , Yin Hang , Liu Yan , Wang Ling , Tang Hailong , Li Youbing
Published: May 2019

In order to develop high-performance dielectric materials, poly(arylene ether nitrile)-based composites were fabricated by employing surface-hydroxylated calcium copper titanate (CCTO) particles. The results indicated that the surface hydroxylation of CCTO effectively improved the interfacial compatibility between inorganic fillers and the polymer matrix. The composites exhibit not only high glass transition temperatures and an excellent thermal stability, but also excellent flexibility and good mechanical properties, with a tensile strength over 60 MPa. Furthermore, the composites possess enhanced permittivity, relatively low loss tangent, good permittivity-frequency stability and dielectric-temperature stability under 160 °C. Therefore, it furnishes an effective path to acquire high-temperature-resistant dielectric materials for various engineering applications.
Polyacrylamide Microspheres-Derived Fe3C@N-doped Carbon Nanospheres as Efficient Catalyst for Oxygen Reduction Reaction
Authors: Chen Ming , Jiang Yu , Mei Ping , Zhang Yan , Zheng Xianfeng , Xiao Wei , You Qinliang , Yan Xuemin , Tang Haolin
Published: May 2019

High-performance non-precious metal catalysts exhibit high electrocatalytic activity for the oxygen-reduction reaction (ORR), which is indispensable for facilitating the development of multifarious renewable energy systems. In this work; N-doped carbon-encapsulated Fe3C nanosphere ORR catalysts were prepared through simple carbonization of iron precursors loaded with polyacrylamide microspheres. The effect of iron precursors loading on the electrocatalytic activity for ORR was investigated in detail. The electrochemical measurements revealed that the N-doped carbon-encapsulated Fe3C nanospheres exhibited outstanding electrocatalytic activity for ORR in alkaline solutions. The optimized catalyst possessed more positive onset potential (0.94 V vs. reversible hydrogen electrode (RHE)), higher diffusion limiting current (5.78 mA cm−2), better selectivity (the transferred electron number n > 3.98 at 0.19 V vs. RHE) and higher durability towards ORR than a commercial Pt/C catalyst. The efficient electrocatalytic performance towards ORR can be attributed to the synergistic effect between N-doped carbon and Fe3C as catalytic active sites; and the excellent stability results from the core-shell structure of the catalysts.
Effects of an Organic-Inorganic Hybrid Containing Allyl Benzoxazine and POSS on Thermal Properties and Flame Retardancy of Epoxy Resin
Authors: Liu Benben , Wang Huiling , Guo Xiaoyan , Yang Rongjie , Li Xiangmei
Published: May 2019

A novel organic-inorganic hybrid containing allyl benzoxazine and polyhedral oligomeric silsesquioxane (POSS) was synthesized by the thiol-ene (click) reaction. The benzoxazine (BOZ)-containing POSS (SPOSS-BOZ) copolymerized with benzoxazine/epoxy resin was used to prepare composites of SPOSS-PBZ-E nanocomposites(NPs). The polymerization behavior was monitored by FTIR and non-isothermal differential scanning calorimetry (DSC), which showed that the composites had completely cured with multiple polymerization mechanisms according to the oxazine ring-opening and epoxy resin (EP) polymerization. The thermal properties of the organic–inorganic polybenzoxazine (PBZ) nanocomposites were analyzed by DSC and thermogravimetric analysis (TGA). Furthermore, the X-ray diffraction analysis and the scanning electron microscopy (SEM) micrographs of the SPOSS-PBZ-E nanocomposites indicated that SPOSS was chemically incorporated into the hybrid nanocomposites in the size range of 80–200 nm. The flame retardancy of the benzoxazine epoxy resin composites was investigated by limiting oxygen index (LOI), UL 94 vertical burn test, and cone calorimeter tests. When the amount of SPOSS reached 10% or more, the vertical burning rating of the curing system arrived at V-1, and when the SPOSS-BOZ content reached 20 wt %, the thermal stability and flame retardancy of the material were both improved. Moreover, in the cone calorimeter testing, the addition of SPOSS-BOZ hindered the decomposition of the composites and led to a reduction in the peak heat release rate (pHRR), the average heat release rate (aHRR), and the total heat release (THR) values by about 20%, 25%, and 25%, respectively. The morphologies of the chars were also studied by SEM and energy dispersive X-ray spectroscopy (EDX), and the flame-retardant mechanism of POSS was mainly a condensed-phase flame retardant. The ceramic layer was formed by the enrichment of silicon on the char surface. When there are enough POSS nanoparticles, it can effectively protect the combustion of internal polymers.
Thermal Degradation and Combustion Behaviors of Polyethylene/Alumina Trihydrate/Graphene Nanoplatelets
Authors: Wang Chunfeng , Wang Jihua , Men Zhenlong , Wang Yongliang , Han Zhidong
Published: May 2019

Graphene nanoplatelets (GNPs) were prepared from expanded graphite (EG) with fully exfoliated structure via ball milling coupled with ultrasonication. The structure of multi-layered GNPs was characterized with transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and Raman spectroscopy. By compounding alumina trihydrate (ATH) with GNPs, the well dispersed mixture of ATH/GNP was obtained, and it showed high flame retardant effectiveness in polyethylene (PE). The peak heat release rate (peak-HRR) decreased by 20% was proven by a cone calorimeter with the addition of GNPs as low as 0.2 wt % in PE/ATH. The results of thermogravimetric analysis (TG) illustrated the improved thermal stability and lower weight loss rate of PE/ATH/GNP than PE/ATH. A protective char with GNPs was evidenced by SEM and X-ray photoelectron spectroscopy (XPS). The well exfoliated structure and good dispersion of GNPs accounted for the formation of effective barrier, which made a profound contribution to the enhanced flame retardancy.
Recyclable Self-Healing Polyurethane Cross-Linked by Alkyl Diselenide with Enhanced Mechanical Properties
Authors: Qian Yuqing , An Xiaowei , Huang Xiaofei , Pan Xiangqiang , Zhu Jian , Zhu Xiulin
Published: May 2019

Dynamic structures containing polymers can behave as thermosets at room temperature while maintaining good mechanical properties, showing good reprocessability, repairability, and recyclability. In this work, alkyl diselenide is effectively used as a dynamic cross-linker for the design of self-healing poly(urea–urethane) elastomers, which show quantitative healing efficiency at room temperature, without the need for any catalysts or external interventions. Due to the combined action of the urea bond and amide bond, the material has better mechanical properties. We also compared the self-healing effect of alkyl diselenide-based polyurethanes and alkyl disulfide-based polyurethanes. The alkyl diselenide has been incorporated into polyurethane networks using a para-substituted amine diphenyl alkyl diselenide. The resulting materials not only exhibit faster self-healing properties than the corresponding disulfide-based materials, but also show the ability to be processed at temperatures as low as 60 °C.
Synthesis and Characterization of Graphene Oxide/Chitosan Composite Aerogels with High Mechanical Performance
Authors: Gong Yang , Yu Yingchun , Kang Huixuan , Chen Xiaohong , Liu Hao , Zhang Yue , Sun Yimeng , Song Huaihe
Published: May 2019

Chitosan, a semi-crystalline biomolecule, has attracted wide attention due to its high synthesis flexibility. In this study, to improve the mechanical properties of chitosan aerogels (CSAs), graphene oxide (GO) was extracted and introduced into chitosan aerogels as fillers. The porous CSAs/GO composite aerogels were fabricated by an environmentally friendly freeze-drying process with different GO contents (0, 0.5, 1.0, 1.5, wt.%). The characteristics of the CSAs/GO were investigated by scanning electron microscopy (SEM), mechanical measurements and mercury porosimeter. The crystallinity of samples was characterized by X-ray diffraction (XRD). The mechanism of the effect of graphene oxide on chitosan was studied by Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the microstructure of the samples is developed in the network structure. The porosity of CSAs/GO aerogels is as high as 87.6%, and the tensile strength of the films increased from 6.60 MPa to 10.56 MPa with the recombination of graphene oxide. The crystallinity (CrI) of composite aerogels increased from 27% to 81%, which indicates that graphene oxide improves the mechanical properties of chitosan by chemical crosslinking.