bluuebunny/crossref_metadata_2025 huggingface dataset:
Abrupt Spin Crossover Behavior in a Linear N1,N2-Triazole Bridged Trinuclear Fe(II) Complex
Authors: Li Ai-Min , Hochdörffer Tim , Wolny Juliusz A. , Schünemann Volker , Rentschler Eva
Published: August 2018

The synthesis, structures and magnetic properties of a new trinuclear spin crossover complex [FeII3(pyrtrz)6(TsO)6]·10H2O·2CH3OH (C2) and its analogue binuclear [FeII2(pyrtrz)5(SCN)4]·7H2O (C1), are reported here. These two compounds are synthesized based on the pyrrolyl functionalized Schiff base 1,2,4-triazole ligand 4-((1H-pyrrol-2-yl)methylene-amino)-4H-1,2,4-triazole (pyrtrz), which represent rare discrete multi-nuclear species, with µ2-N1,N2-triazole bridges linking the FeII centers. DC magnetic susceptibility measurements revealed an abrupt single-step spin crossover (SCO) behavior for compound 2 on the central FeII site and single-crystal X-ray diffraction (173 K) showed that this compound crystallizes in the monoclinic space group (P21/c), and multiple intramolecular interactions were found responsible for the abrupt transition. Compound 1 is a binuclear complex with thiocyanate as terminal ligands. This compound stays in high spin state over the whole temperature range and displays weak antiferromagnetic exchange coupling.
First Evidence of Dehydroabietic Acid Production by a Marine Phototrophic Gammaproteobacterium, the Purple Sulfur Bacterium Allochromatium vinosum MT86
Authors: Imhoff Johannes , Sun Mingshuang , Wiese Jutta , Tank Marcus , Zeeck Axel
Published: August 2018

The production of secondary metabolites by a new isolate of the purple sulfur bacterium Allochromatium vinosum, which had shown antibiotic activities during a preliminary study, revealed the production of several metabolites. Growth conditions suitable for the production of one of the compounds shown in the metabolite profile were established and compound 1 was purified. The molecular formula of compound 1 (C20H28O2) was determined by high resolution mass spectra, and its chemical structure by means of spectroscopic methods. The evaluation of these data revealed that the structure of the compound was identical to dehydroabietic acid, a compound known to be characteristically produced by conifer trees, but so far not known from bacteria, except cyanobacteria. The purified substance showed weak antibiotic activities against Bacillus subtilis and Staphylococcus lentus with IC50 values of 70.5 µM (±2.9) and 57.0 µM (±3.3), respectively.
Novel Natural Angiotensin Converting Enzyme (ACE)-Inhibitory Peptides Derived from Sea Cucumber-Modified Hydrolysates by Adding Exogenous Proline and a Study of Their Structure–Activity Relationship
Authors: Li Jianpeng , Liu Zunying , Zhao Yuanhui , Zhu Xiaojie , Yu Rilei , Dong Shiyuan , Wu Haohao
Published: August 2018

Natural angiotensin converting enzyme (ACE)-inhibitory peptides, which are derived from marine products, are useful as antihypertensive drugs. Nevertheless, the activities of these natural peptides are relatively low, which limits their applications. The aim of this study was to prepare efficient ACE-inhibitory peptides from sea cucumber-modified hydrolysates by adding exogenous proline according to a facile plastein reaction. When 40% proline (w/w, proline/free amino groups) was added, the modified hydrolysates exhibited higher ACE-inhibitory activity than the original hydrolysates. Among the modified hydrolysates, two novel efficient ACE-inhibitory peptides, which are namely PNVA and PNLG, were purified and identified by a sequential approach combining a sephadex G-15 gel column, reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS), before we conducted confirmatory studies with synthetic peptides. The ACE-inhibitory activity assay showed that PNVA and PNLG exhibited lower IC50 values of 8.18 ± 0.24 and 13.16 ± 0.39 μM than their corresponding truncated analogs (NVA and NLG), respectively. Molecular docking showed that PNVA and PNLG formed a larger number of hydrogen bonds with ACE than NVA and NLG, while the proline at the N-terminal of peptides can affect the orientation of the binding site of ACE. The method developed in this study may potentially be applied to prepare efficient ACE-inhibitory peptides, which may play a key role in hypertension management.
Green Synthesis of Gold Nanoparticles Using Carrageenan Oligosaccharide and Their In Vitro Antitumor Activity
Authors: Chen Xiangyan , Zhao Xia , Gao Yanyun , Yin Jiaqi , Bai Mingyue , Wang Fahe
Published: August 2018

Gold nanoparticles (AuNPs) have been widely used in catalysis, photothermal therapy, and targeted drug delivery. Carrageenan oligosaccharide (CAO) derived from marine red algae was used as a reducing and capping agent to obtain AuNPs by an eco-friendly, efficient, and simple synthetic route for the first time. The synthetic conditions of AuNPs were optimized by response surface methodology (RSM), and the CAO-AuNPs obtained were demonstrated to be ellipsoidal, stable and crystalline by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The CAO-AuNPs showed localized surface plasmon resonance (LSPR) oscillation at about 530 nm with a mean diameter of 35 ± 8 nm. The zeta potential of CAO-AuNPs was around −20 mV, which was related to the negatively charged CAO around AuNPs. The CAO-AuNPs exhibited significant cytotoxic activities to HCT-116 and MDA-MB-231 cells, which could be a promising nanomaterial for drug delivery.
Total Polyphenol Content and Antioxidant Capacity of Rosehips of Some Rosa Species
Authors: Koczka Noémi , Stefanovits-Bányai Éva , Ombódi Attila
Published: August 2018

Background: Rosehips, the fruits of Rosa species, are well known for their various health benefits like strengthening the immune system and treating digestive disorders. Antioxidant, anti-inflammatory, and cell regenerative effects are also among their health enhancing impacts. Rosehips are rich in compounds having antioxidant properties, like vitamin C, carotenoids, and phenolics. Methods: Total polyphenol content (Folin-Ciocalteu’s method), and in vitro total antioxidant capacity (ferric-reducing ability of plasma, FRAP) in rosehips of four Rosa species (R. canina, R. gallica, R. rugosa, R. spinosissima) were determined and compared. Ripe fruits were harvested at two locations. Water and ethanolic extracts of dried fruit flesh were analyzed. Results:R. spinosissima had the highest total phenolic content and antioxidant capacity, significantly higher than the other investigated Rosa species. Both parameters were reported in decreasing order for R. spinosissima > R. canina > R. rugosa > R. gallica. Ethanolic extracts of rosehips showed higher phenolic content and antioxidant activity than water extracts. Antioxidant properties were influenced by the growing site of Rosa species. Conclusions: This study indicates that R. spinosissima exhibited the greatest phenolic and antioxidant content, and therefore can be used as a reliable source of natural antioxidants, and serve as a suitable species for further plant breeding activities. Furthermore, investigations of various Rosa species for their antioxidant properties may draw more attention to their potential as functional foods.
Care Bundles after Discharging Patients with Chronic Obstructive Pulmonary Disease Exacerbation from the Emergency Department
Authors: Gómez-Angelats Elisenda , Sánchez Carolina
Published: August 2018

Chronic obstructive pulmonary disease (COPD) is the second leading cause of emergency department (ED) admissions to hospital, and nearly a third of patients with acute exacerbation (AE) of COPD are re-admitted to hospital within 28 days after discharge. It has been suggested that nearly a third of COPD admissions could be avoided through the implementation of evidence-based care interventions. A COPD discharge bundle is a set of evidence-based practices, aimed at improving patient outcomes after discharge from AE COPD; body of evidence supports the usefulness of discharge care bundles after AE of COPD, although there is a lack of consensus of what interventions should be implemented. On the other hand, the implementation of those interventions also involves different challenges. Important care gaps remain regarding discharge care bundles for patients with acute exacerbation of COPD discharged from EDs There is an urgent need for investigations to guide future implementation of care bundles for those patients discharged from EDs.
Low Dispersity and High Conductivity Poly(4-styrenesulfonic acid) Membranes Obtained by Inexpensive Free Radical Polymerization of Sodium 4-styrenesulfonate
Authors: Sepulveda Victor , Sierra Ligia , López Betty
Published: August 2018

Controlled polymerizations are often used to synthesize polymers with low dispersity, which involves expensive initiators, constrained atmospheres, and multi-step purifying processes, especially with water soluble monomers. These drawbacks make the synthesis very expensive and of little industrial value. In this report, an inexpensive free radical polymerization of sodium 4-styrenesulfonate, using benzoyl peroxide as initiator in water/N,N-dimethylformamide solutions, is presented. After polymerization, an easy fiber precipitation method is implemented to extract and purify the polymer, obtaining conversions up to 99%, recoveries up to 98%, and molecular weight dispersities in the range of 1.15–1.85, where the pseudo-controlled behavior is attributed to a thermodynamic limiting molecular weight solubility. Three different methods were used to bring the polymer to its acid form, obtaining Ion Exchange Capacities as high as 4.8 meq/g. Finally, polymeric membranes were prepared and reached conductivities up to 164 mS/cm, which makes them good candidates as proton exchange membranes in fuel cells.
High-Temperature Deformability of a Fe-Cr-Mn-Ni Austenite Stainless Steel with High Nitrogen and High Carbon Contents
Authors: Lee Byung Ju , Song Jae Sook , Hong Sun Ig
Published: August 2018

High temperature deformability and fracture behavior of deformation-processed high nitrogen high carbon Fe-Cr-Mn-Ni stainless steel rods were studied. The effective fracture elongation increased rapidly from 1000 °C, and reached high values (>45%) at 1100–1200 °C, accompanied by strain softening and stress serrations, supporting periodic dynamic recrystallization (DRX). Dynamically recrystallized grains were observed close to the fracture surface, suggesting that active DRX worked until its fracture. Pre-deformation-annealing of Fe-Cr-Mn-Ni stainless steel rods at 1200 °C was found to deteriorate in deformability above 1000 °C, while it enhanced ductility below 950 °C. Pre-deformation annealing had a negative effect on the deformability above 1000 °C due to the reduction of driving forces for DRX, but it exhibited a beneficial effect on the ductility at lower temperatures because of the ease of slip in large-grained structures. The fracture surface at 1250 °C exhibited intergranular fractures due to partial melting at grain boundaries, supported by the thermodynamic calculation of the solidus temperature of Fe-Cr-Mn-Ni austenite stainless steel. In this study, effective fracture elongation, defined based on the assumption that the effective gage length decreases with straining, was found to be an accurate measure of hot deformability.
Joining of Aluminium Alloy Sheets to Aluminium Alloy Foam Using Metal Glasses
Authors: Bangash Muhammad Kashif , Ubertalli Graziano , Di Saverio Davide , Ferraris Monica , Jitai Niu
Published: August 2018

Aluminium alloy foam is a lightweight material with high energy absorption properties and can potentially replace bulk Al-components. The aim of this work is to develop a brazing technique to join aluminium facing sheets to aluminium alloy foam to obtain aluminium foam sandwich panels for applications where high service temperature is a requirement. Al-6016 alloy sheets were brazed to aluminium alloy foam using two aluminium based (Al-Cu-Mg and Al-Si-Mg-Ti) metal glasses at 560 °C–590 °C in an argon atmosphere. Microstructure and microhardness profiles of the aluminium alloy sheet/aluminium alloy foam brazed joints were analysed using a microhardness tester and scanning electron microscope equipped with electron dispersion spectroscopy. A three-point bending test was conducted to study the flexural behaviour of the aluminium foam sandwich composite panels.
Effect of Mg Treatment on Refining the Microstructure and Improving the Toughness of the Heat-Affected Zone in Shipbuilding Steel
Authors: Wang Yan , Zhu Liguang , Zhang Qingjun , Zhang Caijun , Wang Shuoming
Published: August 2018

The effect of Mg treatment on the microstructure and toughness of the heat-affected zone (HAZ) of shipbuilding steel after high-heat-input welding was investigated via laboratory and industrial testing. The welding process and Charpy impact tests were also carried out to evaluate the HAZ toughness of steel plates. First, typical inclusion characteristics were characterised with an ASPEX PSEM Explorer. Then, confocal laser scanning microscopy (CLSM) was used to observe the diameters of austenite grains under different holding times. The results showed that when the addition of microalloy elements were in the order of Al–Mg–Ti, this had an effect on dispersing inclusions, the largest proportion of which were micro-inclusions that had a particle size range of 1.0–1.5 μm. This accounted for 25.4% of the total inclusions, which was the highest amount. The micro inclusion particle size that was mainly distributed in the range of 0.5–3.5 μm accounted for 82.8% of all the micro-inclusions. The inclusion structure induced intragranular acicular ferrite (IAF) in austenite as follows: MgO and Al2O3 formed the core and Ti2O3 adhered to the Al–Mg complex inclusions to produce smaller particle sizes and dispersions of Al, Mg, and Ti complex inclusions. The 40-mm-thick plate obtained in the industrial test after welding had an average impact absorbed energy 2 mm from the weld joint in the heat-affected zone of 198.9 J at −20 °C, while the welding heat input was 150 kJ/cm, compared with the parent material’s low-temperature performance, which exceeded 88%.
Additional Phases at High Boron Content in High-Temperature Co–Re–Cr Alloys
Authors: Beran Přemysl , Mukherji Debashis , Strunz Pavel , Gilles Ralph , Karge Lukas , Hofmann Michael , Hoelzel Markus , Rösler Joachim , Farkas Gergely
Published: August 2018

Boron largely increases the ductility of polycrystalline high-temperature Co–Re–Cr alloys. Therefore, the effect of boron addition on the alloy structural characteristics is of large importance for the stability of the alloy at operational temperatures. Along with the Co-solid solution matrix phase transformation from hcp to fcc structure, additional structural effects were observed in situ at very high temperatures (up to 1500 °C) using neutron diffraction (ND) in boron-containing Co–17Re–23Cr alloys. Increasing boron content up to 1000 wt. ppm lowers the temperature at which sublimation of Co and Cr from the matrix occurs. As a result, the composition of the matrix in the surface region is changed leading to the formation of a second and a third matrix hcp phases at high temperatures. The consideration on the lattice parameter dependence on composition was used to identify the new phases appearing at high temperatures. Energy-dispersive spectroscopy and ND results were used to estimate the amount of Co and Cr which sublimated from the surface region of the high-boron sample. In the sense of alloy development, the sublimation of Co and Cr is not critical as the temperature range where it is observed (≥1430 °C) is significantly above the foreseen operation temperature of the alloys (1200 °C).
Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation
Authors: Toshiyuki Matsumi Carlos , José da Silva Wilson , Kurt Schneider Fábio , Miguel Maia Joaquim , E. M. Morales Rigoberto , Duarte Araújo Filho Walter
Published: August 2018

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.
The Compressive Strength and Microstructure of Alkali-Activated Binary Cements Developed by Combining Ceramic Sanitaryware with Fly Ash or Blast Furnace Slag
Authors: Cosa Juan , Soriano Lourdes , Borrachero María Victoria , Reig Lucía , Payá Jordi , Monzó José María
Published: August 2018

The properties of a binder developed by the alkali-activation of a single waste material can improve when it is blended with different industrial by-products. This research aimed to investigate the influence of blast furnace slag (BFS) and fly ash (FA) (0–50 wt %) on the microstructure and compressive strength of alkali-activated ceramic sanitaryware (CSW). 4 wt % Ca(OH)2 was added to the CSW/FA blended samples and, given the high calcium content of BFS, the influence of BFS was analyzed with and without adding Ca(OH)2. Mortars were used to assess the compressive strength of the blended cements, and their microstructure was investigated in pastes by X-ray diffraction, thermogravimetry, and field emission scanning electron microscopy. All the samples were cured at 20 °C for 28 and 90 days and at 65 °C for 7 days. The results show that the partial replacement of CSW with BFS or FA allowed CSW to be activated at 20 °C. The CSW/BFS systems exhibited better mechanical properties than the CSW/FA blended mortars, so that maximum strength values of 54.3 MPa and 29.4 MPa were obtained in the samples prepared with 50 wt % BFS and FA, respectively, cured at 20 °C for 90 days.
AIE/ACQ Effects in Two DR/NIR Emitters: A Structural and DFT Comparative Analysis
Authors: Caruso Ugo , Panunzi Barbara , Diana Rosita , Concilio Simona , Sessa Lucia , Shikler Rafi , Nabha Shiran , Tuzi Angela , Piotto Stefano
Published: August 2018

The effects of aggregation-induced emission (AIE) and of aggregation caused quenching (ACQ) were observed and discussed on two solid materials based on a phenylenevinylene (PV) and a dicyano-PV structure. The brightest emitter in solid films shows a high fluorescence quantum yield in the deep red/near IR (DR/NIR) region (75%). The spectroscopic properties of the two crystalline solids have been described and compared in terms of crystallographic data and time dependent DFT analysis. The influence of the cyano-substituents on AIE/ACQ mechanism activation was discussed.
tert-Butylphenolic Derivatives from Paenibacillus odorifer—A Case of Bioconversion
Authors: Nguyen Thi-Bach-Le , Delalande Olivier , Rouaud Isabelle , Ferron Solenn , Chaillot Laura , Pedeux Rémy , Tomasi Sophie
Published: August 2018

Two compounds (1) and (2) containing tert-butylphenol groups were, for the first time, produced during the culture of Paenibacillus odorifer, a bacterial strain associated with the crustose lichen, Rhizocarpon geographicum. Their entire structures were identified by one-dimensional (1D) and two-dimensional (2D) NMR and high-resolution electrospray ionisation mass spectrometry (HRESIMS) spectroscopic analyses. Among them, Compound 1 exhibited significant cytotoxicity against B16 murine melanoma and HaCaT human keratinocyte cell lines with micromolar half maximal inhibitory concentration (IC50) values. Furthermore, after supplementation studies, a putative biosynthesis pathway was proposed for Compound 1 throughout a bioconversion by this bacterial strain of butylated hydroxyanisole (BHA), an antioxidant polymer additive.
A Simple, Sensitive, and Reliable Method for the Simultaneous Determination of Multiple Antibiotics in Vegetables through SPE-HPLC-MS/MS
Authors: Feng Yao , Zhang Wen-Juan , Liu Yuan-Wang , Xue Jian-Ming , Zhang Shu-Qing , Li Zhao-Jun
Published: August 2018

Antibiotics, widely used in livestock breeding, enter the environment through animal manure because of incomplete absorption in animals, especially the farmland ecosystem. Therefore, antibiotics may be adsorbed by plants and even become hazardous to human health through the food chain. In this study, a simple, sensitive, and reliable method was developed for the simultaneous determination of eleven antibiotics, including four sulfonamides, two tetracyclines, three fluoroquinolones, tylosin, and chloramphenicol in different vegetable samples using SPE-HPLC-MS/MS. Vegetable samples were extracted by acetonitrile added with hydrochloric acid (125:4, v/v). The extracts were enriched by circumrotating evaporation, and then cleaned through SPE on a hydrophilic-lipophilic balance (HLB) cartridge. All compounds were determined on a C18 reverse phase column through HPLC-MS/MS. The mean recoveries of 11 antibiotics from spiked samples of vegetables ranged from 71.4% to 104.0%. The limits of detection and quantification were 0.06–1.88 μg/kg and 0.20–6.25 μg/kg, respectively. The applicability of this technique demonstrated its good selectivity, high efficiency, and convenience by the analysis of 35 vegetable samples available from a vegetable greenhouse. Antibiotic residues in vegetables have aroused wide concern from the public. Therefore, standards should be established for antibiotic residues in vegetables to ensure food safety and human health.
Truly Target-Focused Pharmacophore Modeling: A Novel Tool for Mapping Intermolecular Surfaces
Authors: Mortier Jérémie , Dhakal Pratik , Volkamer Andrea
Published: August 2018

Pharmacophore models are an accurate and minimal tridimensional abstraction of intermolecular interactions between chemical structures, usually derived from a group of molecules or from a ligand-target complex. Only a limited amount of solutions exists to model comprehensive pharmacophores using the information of a particular target structure without knowledge of any binding ligand. In this work, an automated and customable tool for truly target-focused (T²F) pharmacophore modeling is introduced. Key molecular interaction fields of a macromolecular structure are calculated using the AutoGRID energy functions. The most relevant points are selected by a newly developed filtering cascade and clustered to pharmacophore features with a density-based algorithm. Using five different protein classes, the ability of this method to identify essential pharmacophore features was compared to structure-based pharmacophores derived from ligand-target interactions. This method represents an extremely valuable instrument for drug design in a situation of scarce ligand information available, but also in the case of underexplored therapeutic targets, as well as to investigate protein allosteric pockets and protein-protein interactions.
Atriplex mollis Desf. Aerial Parts: Extraction Procedures, Secondary Metabolites and Color Analysis
Authors: Boutaoui Nassima , Zaiter Lahcene , Benayache Fadila , Benayache Samir , Cacciagrano Francesco , Cesa Stefania , Secci Daniela , Carradori Simone , Giusti Anna Maria , Campestre Cristina , Menghini Luigi , Locatelli Marcello
Published: August 2018

A method using high-performance liquid chromatography coupled with a photodiode array detector was proposed for the rapid characterization of different phenolic constituents from the extracts of Atriplex mollis aerial parts. Atriplex species are known for their multiple biological activities, but no information is available in the literature about A. mollis. With the aim to firstly characterize the main secondary metabolites of this plant, so as to orient better the biological evaluation, we applied three different extraction procedures and compared the chromatographic results. Microwave-assisted extraction gave the best yield and recovery of important compounds such as gallic acid, catechin, chlorogenic acid, p-OH benzoic acid, rutin, sinapinic acid, t-ferulic acid, naringenin and benzoic acid. These constituents belong to three important chemical classes: phenolic acids, flavonoids and monoterpenes. Color evaluation and analysis of chlorophylls (a and b) and carotenoids complete the preliminary profile of this plant. From these analyses, Atriplex mollis is a source of bioactive compounds (especially rutin, t-ferulic acid and gallic acid) and could be recommended as a plant of phyto-pharmaceutical relevance, opening new perspectives on this salt-tolerant plant.
Evolution of In Silico Strategies for Protein-Protein Interaction Drug Discovery
Authors: Macalino Stephani Joy Y. , Basith Shaherin , Clavio Nina Abigail B. , Chang Hyerim , Kang Soosung , Choi Sun
Published: August 2018

The advent of advanced molecular modeling software, big data analytics, and high-speed processing units has led to the exponential evolution of modern drug discovery and better insights into complex biological processes and disease networks. This has progressively steered current research interests to understanding protein-protein interaction (PPI) systems that are related to a number of relevant diseases, such as cancer, neurological illnesses, metabolic disorders, etc. However, targeting PPIs are challenging due to their “undruggable” binding interfaces. In this review, we focus on the current obstacles that impede PPI drug discovery, and how recent discoveries and advances in in silico approaches can alleviate these barriers to expedite the search for potential leads, as shown in several exemplary studies. We will also discuss about currently available information on PPI compounds and systems, along with their usefulness in molecular modeling. Finally, we conclude by presenting the limits of in silico application in drug discovery and offer a perspective in the field of computer-aided PPI drug discovery.
Design, Synthesis, and Antiproliferative Evaluation of Novel Coumarin/2-Cyanoacryloyl Hybrids as Apoptosis Inducing Agents by Activation of Caspase-Dependent Pathway
Authors: Zhang Yu-Ying , Zhang Qian-Qian , Song Jia-Li , Zhang Liang , Jiang Cheng-Shi , Zhang Hua
Published: August 2018

A series of novel coumarin/2-cyanoacryloyl hybrids were prepared and evaluated for their in vitro anticancer activity. Among them, two analogs 5p and 5q showed promising antiproliferative activity against a panel of cancer cell lines, including A549, H157, HepG2, MCF7, MG63, and U2OS. Particularly, 5q showed the most potent activity towards MG63 cells with an IC50 value of 5.06 ± 0.25 μM. Morphological observation and 4,6-diamidino-2-phenylindole (DAPI) staining assay showed that 5q-treated MG63 cells displayed significant apoptosis characteristics. Moreover, flow cytometric detection of phosphatidylserine externalization revealed that 5q induced MG63 apoptosis in a dose-dependent manner. Real-time PCR and western blot assay further confirmed that 5q had strong effects to induce MG63 cell apoptosis, suggesting that the action was associated with down-regulation of the anti-apoptotic protein Bcl-2, upregulation of pro-apoptotic protein Bax, and induced activation of caspase-3, 8, and 9. The present results provide a new chemotype for anticancer drug development and continuing investigation into candidates with coumarin/2-cyanoacryloyl scaffold is warranted.
In-Situ Conversion of ZnO/Ni3ZnC0.7/CNT Composite from NiZn Bimetallic MOF Precursor with Enhanced Electromagnetic Property
Authors: Huang Lina , Huang Shaolong , Yang Ziyu , Zhao Ailun , Liu Chengxiang , Lu Jianguo , Ruan Shuangchen , Zeng Yu-jia
Published: August 2018

ZnO/Ni3ZnC0.7/x% CNT (x = 0, 2, 5, 10) urchin-like structures have been synthesized using a facile method based on metal-organic frameworks (MOFs) and applied as the electromagnetic absorber. The results of the experiments demonstrate that the content of multi-wall carbon nanotubes (MWCNT) has a great influence on the absorbing performance of the hybrid material. Conduction loss, interfacial polarization and ferromagnetic resonance all contribute to the electromagnetic absorption. The urchin-like ZnO/Ni3ZnC0.7/5% CNT composite presents excellent absorbing properties. When the filler loading of ZnO/Ni3ZnC0.7/5% CNT composite in paraffin matrix is only 10 wt.%, a minimum reflection loss of −33.2 dB is achieved at a layer thickness of 4.9 mm.
A Low FODMAP Gluten-Free Diet Improves Functional Gastrointestinal Disorders and Overall Mental Health of Celiac Disease Patients: A Randomized Controlled Trial
Authors: Roncoroni Leda , Bascuñán Karla A. , Doneda Luisa , Scricciolo Alice , Lombardo Vincenza , Branchi Federica , Ferretti Francesca , Dell’Osso Bernardo , Montanari Valeria , Bardella Maria Teresa , Elli Luca
Published: August 2018

A subset of patients with celiac disease (CD) on a gluten-free diet (GFD) reported the persistence of functional gastrointestinal disorders. Foods containing fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) can trigger a broad range of gastrointestinal symptoms in sensitive individuals. We evaluated the effects of a low FODMAP diet (LFD) on gastrointestinal and psychological symptomatology in CD patients. A total of 50 celiac patients on GFDs and with persistence of gastrointestinal symptoms were included. The patients were randomly allocated to one of two dietary groups—one on a low FODMAP GFD (LF-GFD, n = 25) and the other on a regular GFD (R-GFD, n = 25)—for 21 days. Psychological symptomatology and quality of life were evaluated by the Symptom Checklist-90-R (SCL-90) and the Short Form (36) Health Survey (SF-36) questionnaires, respectively. Gastrointestinal symptomatology and general well-being were evaluated by visual analogue scale (VAS) scores. After 21 days, 21 and 23 patients completed the dietary treatment on LF-GFD and R-GFD, respectively. A reduced global SCL-90 index (p < 0.0003) was found in the LF-GFD group but not in the R-GFD one. However, the SF-36 scores did not differ between groups after treatment. The VAS for abdominal pain was much lower, and the VAS for fecal consistency enhanced after treatment in the LF-GFD group. General well-being increased in both groups but with a much higher improvement in the LF-GFD (p = 0.03). A short-term LFD regimen helps to improve the psychological health and gastrointestinal symptomatology with enhanced well-being of CD patients with persisting functional gastrointestinal symptomatology. The long-term clinical effects of LFD in particular subgroups of CD patients need further evaluation.
The Potential Protective Effect of Oligoribonucleotides-d-Mannitol Complexes against Thioacetamide-Induced Hepatotoxicity in Mice
Authors: Marchyshak Tetiana , Yakovenko Tetiana , Shmarakov Igor , Tkachuk Zenoviy
Published: August 2018

This study investigated the potential hepatoprotective effect of oligoribonucleotides-d-mannitol complexes (ORNs-d-M) against thioacetamide (TAA)-induced hepatotoxicity in mice. The hepatoprotective activity of ORNs-d-M was evaluated in thioacetamide (TAA)-treated C57BL/6J. Results indicate that treatment with ORNs-d-M displayed a protective effect at the TAA-induced liver injury. Treatment with ORNs-d-M, starting at 0 h after the administration of TAA, decreased TAA-elevated serum alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (GGT). Activities of glutathione S-transferase (GST) and glutathione peroxidase (GPx), and levels of glutathione (GSH), were enhanced with ORNs-d-M administration, while the hepatic oxidative biomarkers (TBA-reactive substances, protein carbonyl derivatives, protein-SH group) and myeloperoxidase (MPO) activity were reduced. Furthermore, genetic analysis has shown that the ORNs-d-M decreases the expression of mRNA pro-inflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6), profibrogenic cytokine-transforming growth factor β1 (TGF-β1), as well as the principal protein of the extracellular matrix—collagen I. The present study demonstrates that ORNs-d-M exerts a protective effect against TAA-induced liver injury, which may be associated with its anti-inflammatory effects, inhibition of overexpression of mRNA cytokines, and direct effects on the metabolism of the toxin.
Electrically and Ultrasonically Enhanced Transdermal Delivery of Methotrexate
Authors: Nguyen Hiep X. , Banga Ajay K.
Published: August 2018

In this study, we used sonophoresis and iontophoresis to enhance the in vitro delivery of methotrexate through human cadaver skin. Iontophoresis was applied for 60 min at a 0.4 mA/sq·cm current density, while low-frequency sonophoresis was applied at a 20 kHz frequency (2 min application, and 6.9 W/sq·cm intensity). The treated skin was characterized by dye binding, transepidermal water loss, skin electrical resistance, and skin temperature measurement. Both sonophoresis and iontophoresis resulted in a significant reduction in skin electrical resistance as well as a marked increase in transepidermal water loss value (p < 0.05). Furthermore, the ultrasonic waves resulted in a significant increase in skin temperature (p < 0.05). In permeation studies, the use of iontophoresis led to a significantly higher drug permeability than the untreated group (n = 4, p < 0.05). The skin became markedly more permeable to methotrexate after the treatment by sonophoresis than by iontophoresis (p < 0.01). A synergistic effect for the combined application of sonophoresis and iontophoresis was also observed. Drug distribution in the skin layers revealed a significantly higher level of methotrexate in the sonicated skin than that in iontophoresis and untreated groups. Iontophoresis and low-frequency sonophoresis were found to enhance the transdermal and intradermal delivery of methotrexate in vitro.
Hydrogels of Polycationic Acetohydrazone-Modified Phosphorus Dendrimers for Biomedical Applications: Gelation Studies and Nucleic Acid Loading
Authors: Apartsin Evgeny K. , Grigoryeva Alina E. , Malrin-Fournol Audrey , Ryabchikova Elena I. , Venyaminova Alya G. , Mignani Serge , Caminade Anne-Marie , Majoral Jean-Pierre
Published: August 2018

In this work, we report the assemblage of hydrogels from phosphorus dendrimers in the presence of biocompatible additives and the study of their interactions with nucleic acids. As precursors for hydrogels, phosphorus dendrimers of generations 1–3 based on the cyclotriphosphazene core and bearing ammonium or pyridinium acetohydrazones (Girard reagents) on the periphery have been synthesized. The gelation was done by the incubation of dendrimer solutions in water or phosphate-buffered saline in the presence of biocompatible additives (glucose, glycine or polyethylene glycol) to form physical gels. Physical properties of gels have been shown to depend on the gelation conditions. Transmission electron microscopy revealed structural units and well-developed network structures of the hydrogels. The hydrogels were shown to bind nucleic acids efficiently. In summary, hydrogels of phosphorus dendrimers represent a useful tool for biomedical applications.
A Randomized Crossover Comparison between Team-Based Learning and Lecture Format on Long-Term Learning Outcomes
Authors: Bleske Barry E. , Remington Tami L. , Wells Trisha D. , Klein Kristin C. , Tingen Jeffrey M. , Dorsch Michael P.
Published: August 2018

There are limited data evaluating the effectiveness of different teaching pedagogies to maintain gains in learning achieved over the short term. The purpose of this study is to compare long-term learning outcomes between two different teaching pedagogies, team-based learning (TBL) and lecture. Within a therapeutic elective course a randomized crossover study was conducted with 30 students divided into two sections. Each section was taught six therapeutic topics (three TBL and three lecture). Six months following completion of the course, 47 assessment questions (application and recall multiple-choice questions) were re-administered to 16 students from the class with no prior announcement of the assessment. The results showed no significant difference in long-term assessment scores between TBL and lecture formats (67 ± 14% vs. 63 ± 16%, p = 0.2, respectively). In addition, there was a significant (p < 0.0001) and similar decline in short-term gains for TBL (90 ± 9% vs. 67 ± 14%) and lecture (86 ± 11% vs. 63 ± 16%) in assessment scores. In conclusion, there was no advantage gained by employing an active-learning pedagogy when assessing multiple-choice questions six months following end of a therapeutics course in a limited sample size. Neither pedagogy was able to maintain short-term gains in learning outcomes as assessed by multiple-choice questions.
Assignment of Regioirregular Sequences in the 13C NMR Spectrum of Syndiotactic Polypropylene
Authors: Cipullo Roberta , Vittoria Antonio , Busico Vincenzo
Published: August 2018

The 13C NMR microstructure of a polypropylene (PP) sample is a fundamental source of information on its properties, and also a ‘fingerprint’ of the catalytic species used to produce it. Likely due to a much greater technological importance, isotactic polymers (i-PP) have been more thoroughly investigated that syndiotactic ones (s-PP). In this paper, we report the first full assignment of regioirregular sequences in s-PP samples made with two well-known molecular catalysts, namely a Cs-symmetric (cyclopentadienyl)(fluorenyl) ansa-zirconocene and a fluxional bis(phenoxyimine)Ti species. The results shed more light on the mechanism of chain propagation at the two catalysts, and open the door to the investigation of more elusive cases like the formation of s-PP blocks in the presence of multi-sited heterogeneous Ziegler-Natta systems.
PDDA-Montmorillonite Composites Loaded with Ru Nanoparticles: Synthesis, Characterization, and Catalytic Properties in Hydrogenation of 2-Butanone
Authors: Serwicka Ewa M. , Zimowska Małgorzata , Duraczyńska Dorota , Napruszewska Bogna D. , Nattich-Rak Małgorzata , Mordarski Grzegorz , Lityńska-Dobrzyńska Lidia , Palkova Helena
Published: August 2018

The effect of synthesis parameters on the physicochemical properties of clay/ polydiallyldimethylammonium (PDDA)/Ru composites and their applicability in hydrogenation of 2-butanone under very mild conditions (room temperature, atmospheric pressure, and aqueous solution) was studied. Three synthetic procedures were employed, differing in the order of addition of components and the stage at which metallic Ru species were generated. The materials were characterized with XRD (X-ray diffraction), XRF (X-ray fluorescence), EDS (energy-dispersive spectroscopy), AFM (atomic force microscopy), TEM/HRTEM (transmission electron microscopy/high resolution transmission electron microscopy), and TG/DSC (thermal gravimetry/differential scanning microscopy techniques. The study revealed that the method of composite preparation affects its structural and thermal properties, and controls the distribution and size of Ru particles. All catalysts are active in hydrogenation of 2-butanone. For best catalytic performance (100% conversion within 30 min) both the size of Ru particles and the load of polymer had to be optimized. Superior catalytic properties were obtained over the composite with intermediate crystal size and intermediate PDDA load, prepared by generation of metallic Ru species in the polymer solution prior to intercalation. This method offers an easy way of controlling the crystal size by modification of Ru/PDDA ratio.
Development and Characterization of Polyamide-Supported Chitosan Nanocomposite Membranes for Hydrophilic Pervaporation
Authors: Chrzanowska Ewelina , Gierszewska Magdalena , Kujawa Joanna , Raszkowska-Kaczor Aneta , Kujawski Wojciech
Published: August 2018

An experimental protocol of preparation of homogeneous and nanocomposite chitosan (Ch) based membranes supported on polyamide-6 (PA6) films was developed and described in detail. Montmorillonite (MMT) and Cloisite 30B (C30B) nanoclays were used as nanofillers to improve mechanical properties of chitosan films. The surface, mechanical, and transport properties of PA6 supported Ch, Ch/MMT and Ch/C30B membranes were studied and compared with a pristine, non-supported chitosan membrane. Implementation of advanced analytical techniques e.g., SEM reveal the clays nanoparticles are well dispersed in the chitosan matrix. According to AFM images, composite chitosan/nanoclay membranes possess higher roughness compared with unfilled ones. On the other hand, an incorporation of clay particles insignificantly changed the mechanical and thermal properties of the membranes. It was also found that all membranes are hydrophilic and water is preferentially removed from EtOH/H2O and iPrOH/H2O mixtures by pervaporation. Supporting of chitosan and chitosan/nanoclay thin films onto PA6 porous substrate enhanced permeate flux and pervaporation separation index, in comparison to the pristine Ch membrane. Concerning separation factor (β), the highest value equal to 4500 has been found for a chitosan composite membrane containing Cloisite 30B contacting 85/15 wt % iPrOH/H2O mixture. The mentioned membrane was characterized by the normalized flux of 0.5 μm·kg·m−2·h−1. Based on the established data, it was possible to conclude that chitosan membranes are meaningful material in dehydration of azeotropic mixtures. Nevertheless, to boost up the membrane efficiency, the further modification process is required.
Characterization of Lignin Extracted from Willow by Deep Eutectic Solvent Treatments
Authors: Lyu Gaojin , Li Tengfei , Ji Xingxiang , Yang Guihua , Liu Yu , Lucia Lucian A. , Chen Jiachuan
Published: August 2018

Purity, morphology, and structural characterization of synthesized deep eutectic solvent (DES)-lignins (D6h, D9h, D12h, D18h, D24h) extracted from willow (Salix matsudana cv. Zhuliu) after treatment with a 1:10 molar ratio of choline chloride and lactic acid at 120 °C for 6, 9, 12, 18, and 24 h were carried out. The purity of DES-lignin was ~95.4%. The proportion of hydrogen (H) in DES-lignin samples increased from 4.22% to 6.90% with lignin extraction time. The DES-lignin samples had low number/weight average molecular weights (1348.1/1806.7 to 920.2/1042.5 g/mol, from D6h to D24h) and low particle sizes (702–400 nm). Atomic force microscopy (AFM) analysis demonstrated that DES-lignin nanoparticles had smooth surfaces and diameters of 200–420 nm. Syringyl (S) units were dominant, and total phenolic hydroxyl content and total hydroxyl content reached their highest values of 2.05 and 3.42 mmol·g−1 in D12h and D6h, respectively. β-Aryl ether (β-O-4) linkages were eliminated during DES treatment.
Novel Dihydroxy-Containing Ammonium Phosphate Based Poly(Lactic Acid): Synthesis, Characterization and Flame Retardancy
Authors: Jian Rong-Kun , Xia Long , Ai Yuan-Fang , Wang De-Yi
Published: August 2018

The aim of this work is to prepare flame-retardant biobased poly(lactic acid) materials through incorporating a novel flame retardant dihydroxy-containing ammonium phosphate (DAP) derived from 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphinane-2-oxide (DOP) and 2-amino-2-methyl-1,3-propanediol (AMPD). Interestingly, PLA modified with only 0.5% DAP passed UL-94 V-0 rating, and possessed a limiting oxygen index (LOI) value of 24.6%, which would further increase with the increasing loading of DAP. PLA/DAP did not exhibit obviously improved results in terms of heat release rate (HRR), as the loading of DAP was relatively low. It was found that DAP showed little effect on the thermal stability of PLA and the onset decomposition temperatures of PLA and PLA/DAP blends were very close. Besides, the degree of crystallization increased because of the plasticized effect of DAP. Based on the analyses of flame-retardant mechanism of DAP, it disclosed that DAP decomposed to generate incombustible compounds, such as water and ammonia, to dilute the concentration of oxygen and fuels, and then release some phosphorus-containing fragments that could produce phosphorus-containing free radicals to interrupt free-radical reactions, and finally noncombustible melt dripping was produced so as to bring away large amount of heat and stop the feedback of heat to the matrix.
Effect of Thermal Processing and Heat Treatment Condition on 3D Printing PPS Properties
Authors: Geng Peng , Zhao Ji , Wu Wenzheng , Wang Yulei , Wang Bofan , Wang Shuobang , Li Guiwei
Published: August 2018

Polyphenylene sulfide (PPS) is a high-performance semi-crystalline thermoplastic polymer that is widely used in the automotive, electronics, and aerospace industries, as well as other fields. However, PPS introduces several challenges in fused deposition modeling owing to its inherent properties of crystallization and thermal crosslinking. The present study demonstrates the effects of the thermal processing and heat treatment conditions on the accuracy and mechanical properties of PPS samples three-dimensionally printed through fused deposition modeling. By measuring the degree of crystallinity and thermal crosslinking of three-dimensionally printed PPS samples, we found that the thermal history affects the three-dimensionally printed PPS properties. Results show that the accuracy of three-dimensionally printed PPS samples can be improved by means of air-forced cooling in fused deposition modeling. The balance between mechanical strength and ductility was regulated by altering the heat treatment conditions. This approach is applicable to eliminating the warpage of semi-crystalline polymer in three-dimensional printing (not only for PPS) and provides a method of improving the mechanical properties of three-dimensionally printed PPS samples.
Advances in Flame Retardant Poly(Lactic Acid)
Authors: Tawiah Benjamin , Yu Bin , Fei Bin
Published: August 2018

PLA has become a commodity polymer with wide applications in a number of fields. However, its high flammability with the tendency to flow in fire has limited its viability as a perfect replacement for the petrochemically-engineered plastics. Traditional flame retardants, which may be incorporated into PLA without severely degrading the mechanical properties, are the organo-halogen compounds. Meanwhile, these compounds tend to bioaccumulate and pose a risk to flora and fauna due to their restricted use. Research into PLA flame retardants has largely focused on organic and inorganic compounds for the past few years. Meanwhile, the renewed interest in the development of environmentally sustainable flame retardants (FRs) for PLA has increased significantly in a bid to maintain the integrity of the polymer. A review on the development of new flame retardants for PLA is presented herein. The focus is on metal oxides, phosphorus-based systems, 2D and 1D nanomaterials, hyperbranched polymers, and their combinations, which have been applied for flame retarding PLA are discussed. The paper also reviews briefly the correlation between FR loadings and efficiency for various FR systems, and their effects on processing and mechanical properties.