bluuebunny/crossref_metadata_2025 huggingface dataset:
Magneto-Electric Effect on Guided Waves in Functionally Graded Piezoelectric–Piezomagnetic Fan-Shaped Cylindrical Structures
Authors: Zhang Bo , Yu Jiangong , Elmaimouni Lahoucine , Zhang Xiaoming
Published: November 2018

Functionally graded piezoelectric–piezomagnetic (FGPP) material simultaneously consists of piezomagnetic and piezoelectric phases, which are able to convert energy among mechanical, electric, and magnetic fields. The magneto-electric effect on waves in FGPP fan-shaped cylindrical structures is studied by exploiting the double Legendre orthogonal polynomial method. By means of the Heaviside function, the initial conditions are brought into wave motion equations. Dispersion properties, electric and magnetic potential, and the Poynting vector are calculated. Subsequently, the effect of the graded variation and geometric size on wave characteristics is analyzed. The FGPP fan-shaped cylindrical structures are of complex geometrical shape and material inhomogeneity, so their influences on the magneto-electric effect are the focus of discussion. Results reveal that the cut-off frequencies have a negative relationship with the cross-section area of the structure. The magneto-electric effect could be adjusted via altering the geometric size of the cross-section. These results can be utilized to design and optimize piezoelectric–piezomagnetic fan-shaped transducers.
Electrospun Produced 3D Matrices for Covering of Vascular Stents: Paclitaxel Release Depending on Fiber Structure and Composition of the External Environment
Authors: Kuznetsov Konstantin A. , Stepanova Alena O. , Kvon Ren I. , Douglas Timothy E. L. , Kuznetsov Nikita A. , Chernonosova Vera S. , Zaporozhchenko Ivan A. , Kharkova Maria V. , Romanova Irina V. , Karpenko Andrey A. , Laktionov Pavel P.
Published: November 2018

Paclitaxel is a natural, highly lipophilic anti proliferative drug widely used in medicine. We have studied the release of tritium-labeled paclitaxel (3H-PTX) from matrices destined for the coating of vascular stents and produced by the electrospinning method from the solutions of polycaprolactone (PCL) with paclitaxel (PTX) in hexafluoisopropanol (HFIP) and/or solutions of PCL with PTX and human serum albumin (HSA) in HFIP or HIFP-dimethyl sulphoxide (DMSO) blend. The release of PTX has been shown to depend on the composition of electrospinning solution, as well as the surrounding medium, particularly the concentration of free PTX and PTX-binding biomolecules present in human serum. It was shown that 3D matrices can completely release PTX without weight loss. Two-phase PTX release from optimized 3D matrices was obtained: ~27% of PTX was released in the first day, another 8% were released over the next 26 days. Wherein ~2.8%, ~2.3%, and ~0.25% of PTX was released on day 3, 9, and 27, respectively. Considering PTX toxicity, the rate of its diffusion through the arterial wall, and the data obtained the minimum cytostatic dose of the drug in the arterial wall will be maintained for at least three months.
The Effect of Varying Almond Shell Flour (ASF) Loading in Composites with Poly(Butylene Succinate (PBS) Matrix Compatibilized with Maleinized Linseed Oil (MLO)
Authors: Liminana Patricia , Quiles-Carrillo Luis , Boronat Teodomiro , Balart Rafael , Montanes Nestor
Published: November 2018

In this work poly(butylene succinate) (PBS) composites with varying loads of almond shell flour (ASF) in the 10–50 wt % were manufactured by extrusion and subsequent injection molding thus showing the feasibility of these combined manufacturing processes for composites up to 50 wt % ASF. A vegetable oil-derived compatibilizer, maleinized linseed oil (MLO), was used in PBS/ASF composites with a constant ASF to MLO (wt/wt) ratio of 10.0:1.5. Mechanical properties of PBS/ASF/MLO composites were obtained by standard tensile, hardness, and impact tests. The morphology of these composites was studied by field emission scanning electron microscopy—FESEM) and the main thermal properties were obtained by differential scanning calorimetry (DSC), dynamical mechanical-thermal analysis (DMTA), thermomechanical analysis (TMA), and thermogravimetry (TGA). As the ASF loading increased, a decrease in maximum tensile strength could be detected due to the presence of ASF filler and a plasticization effect provided by MLO which also provided a compatibilization effect due to the interaction of succinic anhydride polar groups contained in MLO with hydroxyl groups in both PBS (hydroxyl terminal groups) and ASF (hydroxyl groups in cellulose). FESEM study reveals a positive contribution of MLO to embed ASF particles into the PBS matrix, thus leading to balanced mechanical properties. Varying ASF loading on PBS composites represents an environmentally-friendly solution to broaden PBS uses at the industrial level while the use of MLO contributes to overcome or minimize the lack of interaction between the hydrophobic PBS matrix and the highly hydrophilic ASF filler.
Optimization of Process Parameters for Preparing Metallic Matrix Diamond Tool Bits by Microwave Pressureless Sintering Using Response Surface Methodology
Authors: Yang Li , Wang Liang , Gao Jiyun , Guo Shenghui , Ye Xiaolei , Koppala Sivasankar , Hu Tu , Hou Ming , Hu Longtao
Published: November 2018

The process of preparing metallic matrix diamond tool bits by microwave pressureless sintering (MPS) was exclusively studied in this paper. The effects of the sintering temperature, the cold pressure, and the holding time on the mechanical properties of the bit were determined by using the response surface methodology (RSM) with Box-Behnken Design (BBD). In addition, with RSM, the second-order polynomial equation of mechanical properties was obtained. The solutions were well matched with the experimental values. This indicates that major variations in mechanical properties of the sintered sample could be predicted by the models, which shows that the applied model is accurate. Conventional pressureless sintering (CPS) experiments were also conducted to make a comparison. The experimental results showed that the MPS can enhance the mechanical properties of sintered samples. A possible MPS mechanism is proposed in this work after analyzing all the experimental results.
CO2 Uptake of Carbonation-Cured Cement Blended with Ground Volcanic Ash
Authors: Seo Joon Ho , Amr Issam T. , Park Sol Moi , Bamagain Rami A. , Fadhel Bandar A. , Kim Gwang Mok , Hunaidy Ali S. , Lee Haeng Ki
Published: November 2018

Accelerated carbonation curing (ACC) as well as partial replacement of cement with natural minerals are examples of many previous approaches, which aimed to produce cementitious products with better properties and environmental amicabilities. In this regard, the present study investigates CO2 uptake of carbonation-cured cement blended with ground Saudi Arabian volcanic ash (VA). Paste samples with cement replacement of 20%, 30%, 40%, and 50% by mass were prepared and carbonation-cured after initial curing of 24 h. A compressive strength test, X-ray diffractometry (XRD), and thermogravimetry were performed. Although pozzolanic reaction of VA hardly occurred, unlike other pozzolana in blended cement, the results revealed that incorporation of VA as a supplementary cementitious material significantly enhanced the compressive strength and diffusion of CO2 in the matrix. This increased the CO2 uptake capacity of cement, reducing the net CO2 emission upon carbonation curing.
Micro-Segregated Liquid Crystal Haze Films for Photovoltaic Applications: A Novel Strategy to Fabricate Haze Films Employing Liquid Crystal Technology
Authors: Bae Jae-Hyun , Jung Eui Dae , Nam Yun Seok , Kim Byeong-Cheon , Choi Hyeon-Joon , Kim Hyun Gi , Song Myoung Hoon , Choi Suk-Won
Published: November 2018

Herein, a novel strategy to fabricate haze films employing liquid crystal (LC) technology for photovoltaic (PV) applications is reported. We fabricated a high optical haze film composed of low-molecular LCs and polymer and applied the film to improve the energy conversion efficiency of PV module. The technique utilized to fabricate our haze film is based on spontaneous polymerization-induced phase separation between LCs and polymers. With optimized fabrication conditions, the haze film exhibited an optical haze value over 95% at 550 nm. By simply attaching our haze film onto the front surface of a silicon-based PV module, an overall average enhancement of 2.8% in power conversion efficiency was achieved in comparison with a PV module without our haze film.
Characterization and Corrosion Resistance of Boron-Containing-Austenitic Stainless Steels Produced by Rapid Solidification Techniques
Authors: Koga Guilherme Y. , Otani Lucas B. , Silva Ana M. B. , Roche Virginie , Nogueira Ricardo P. , Jorge Alberto M. , Bolfarini Claudemiro , Kiminami Claudio S. , Botta Walter J.
Published: November 2018

The composition of a commercial duplex stainless steel was modified with boron additions (3.5, 4.5, and 5.5 wt.%) and processed by rapid-quenching techniques: Melt-spinning, copper-mold casting, and high-velocity oxygen fuel (HVOF). Spray deposition was also used to produce alloys as the process may induce rapid-solidified-like microstructures. These processing routes led to microstructures with distinguished corrosion resistance. Among the alloys with different boron contents, the 63.5Fe25Cr7Ni4.5B composition enabled the production of fully amorphous ribbons by melt-spinning. The cooling rate experienced during copper-mold casting, high-velocity oxygen fuel, and spray deposition did not ensure complete amorphization. The crystalline phases thereby formed were (Fe,Cr)2B and (Fe,Mo)3B2 borides in an austenitic-matrix with morphology and refinement dependent of the cooling rates. Fully amorphous 63.5Fe25Cr7Ni4.5B ribbons exhibited outstanding corrosion resistance in chloride-rich alkaline and acid media with negligible corrosion current densities of about 10−8 A/cm² and a broad passivation plateau. Although the specimens of the same composition produced by HVOF process and spray deposition exhibited lower corrosion resistance because of intrinsic porosity and crystalline phases, their corrosion behaviors were superior to those of AISI 1045 steel used as substrate with the advantage to be reinforced with hard borides known to be resistant against wear.
Open-Ring Butenolides from a Marine-Derived Anti-Neuroinflammatory Fungus Aspergillus terreus Y10
Authors: Yang Long-He , Ou-Yang Han , Yan Xia , Tang Bo-Wen , Fang Mei-Juan , Wu Zhen , Chen Jing-Wei , Qiu Ying-Kun
Published: November 2018

To investigate structurally novel and anti-neuroinflammatory natural compounds from marine-derived microorganisms, the secondary metabolites of Aspergillus terreus Y10, a fungus separated from the sediment of the coast in the South China Sea, were studied. Three new compounds (2–4), with novel open-ring butenolide skeletons, were isolated from the ethyl acetate extract of the culture medium. In addition, a typical new butenolide, asperteretal F (1), was found to dose-dependently inhibit tumor necrosis factor (TNF-α) generation with an IC50 of 7.6 μg/mL. The present study shows the existence of open-ring butenolides, and suggests that butenolides such as asperteretal F (1) are a promising new anti-neuroinflammatroy candidate for neurodegenerative diseases.
Reclamation of Marine Chitinous Materials for Chitosanase Production via Microbial Conversion by Paenibacillus macerans
Authors: Doan Chien Thang , Tran Thi Ngoc , Nguyen Van Bon , Nguyen Anh Dzung , Wang San-Lang
Published: November 2018

Chitinous materials from marine byproducts elicit great interest among biotechnologists for their potential biomedical or agricultural applications. In this study, four kinds of marine chitinous materials (squid pens, shrimp heads, demineralized shrimp shells, and demineralized crab shells) were used to screen the best source for producing chitosanase by Paenibacillus macerans TKU029. Among them, the chitosanase activity was found to be highest in the culture using the medium containing squid pens as the sole carbon/nitrogen (C/N) source. A chitosanase which showed molecular weights at 63 kDa was isolated from P. macerans cultured on a squid pens medium. The purified TKU029 chitosanase exhibited optimum activity at 60 °C and pH 7, and was stable at temperatures under 50 °C and pH 3-8. An analysis by MALDI-TOF MS revealed that the chitosan oligosaccharides (COS) obtained from the hydrolysis of water-soluble chitosan by TKU029 crude enzyme showed various degrees of polymerization (DP), varying from 3–6. The obtained COS enhanced the growth of four lactic acid bacteria strains but exhibited no effect on the growth of E. coli. By specialized growth enhancing effects, the COS produced from hydrolyzing water soluble chitosan with TKU029 chitinolytic enzymes could have potential for use in medicine or nutraceuticals.
Influence of Preparation Methods of Chitooligosaccharides on Their Physicochemical Properties and Their Anti-Inflammatory Effects in Mice and in RAW264.7 Macrophages
Authors: Sánchez Ángela , Mengibar María , Fernández Margarita , Alemany Susana , Heras Angeles , Acosta Niuris
Published: November 2018

The methods to obtain chitooligosaccharides are tightly related to the physicochemical properties of the end products. Knowledge of these physicochemical characteristics is crucial to describing the biological functions of chitooligosaccharides. Chitooligosaccharides were prepared either in a single-step enzymatic hydrolysis using chitosanase, or in a two-step chemical-enzymatic hydrolysis. The hydrolyzed products obtained in the single-step preparation were composed mainly of 42% fully deacetylated oligomers plus 54% monoacetylated oligomers, and they attenuated the inflammation in lipopolysaccharide-induced mice and in RAW264.7 macrophages. However, chitooligosaccharides from the two-step preparation were composed of 50% fully deacetylated oligomers plus 27% monoacetylated oligomers and, conversely, they promoted the inflammatory response in both in vivo and in vitro models. Similar proportions of monoacetylated and deacetylated oligomers is necessary for the mixtures of chitooligosaccharides to achieve anti-inflammatory effects, and it directly depends on the preparation method to which chitosan was submitted.
The Antibacterial and Anti-Eukaryotic Type VI Secretion System MIX-Effector Repertoire in Vibrionaceae
Authors: Dar Yasmin , Salomon Dor , Bosis Eran
Published: November 2018

Vibrionaceae is a widespread family of aquatic bacteria that includes emerging pathogens and symbionts. Many Vibrionaceae harbor a type VI secretion system (T6SS), which is a secretion apparatus used to deliver toxins, termed effectors, into neighboring cells. T6SSs mediate both antibacterial and anti-eukaryotic activities. Notably, antibacterial effectors are encoded together with a gene that encodes a cognate immunity protein so as to antagonize the toxicity of the effector. The MIX (Marker for type sIX effectors) domain has been previously defined as a marker of T6SS effectors carrying polymorphic C-terminal toxins. Here, we set out to identify the Vibrionaceae MIX-effector repertoire and to analyze the various toxin domains they carry. We used a computational approach to search for the MIX-effectors in the Vibrionaceae genomes, and grouped them into clusters based on the C-terminal toxin domains. We classified MIX-effectors as either antibacterial or anti-eukaryotic, based on the presence or absence of adjacent putative immunity genes, respectively. Antibacterial MIX-effectors carrying pore-forming, phospholipase, nuclease, peptidoglycan hydrolase, and protease activities were found. Furthermore, we uncovered novel virulence MIX-effectors. These are encoded by “professional MIXologist” strains that employ a cocktail of antibacterial and anti-eukaryotic MIX-effectors. Our findings suggest that certain Vibrionaceae adapted their antibacterial T6SS to mediate interactions with eukaryotic hosts or predators.
Factors Associated with Perceived Life Chaos among Post-Myocardial Infarction Survivors in a Malaysian Cardiac Care Facility
Authors: Ganasegeran Kurubaran , Rashid Abdul
Published: November 2018

Background and objectives: Survivors of chronic life-threatening conditions like myocardial infarction (MI) are often confronted with multiple physical and psychological stressors as a consequence of elevated demands of lifestyle adjustments and modifications. Such stressors, collectively known as “life chaos”, cause disruption to one’s lifestyle equilibrium of having organized, calm, and regular routines. The objective of the current study was to determine the level of life chaos and its associated correlates among post-myocardial infarction (post-MI) survivors in Malaysia. Materials and Methods: An analytical cross-sectional study was conducted among 242 post-MI survivors in a Malaysian cardiac health facility from July to September 2016. A self-administered questionnaire in Malay that consisted of items on socio-demographics, health attributes, validated OSLO-3 Social Support Scale (OSS-3), and the Modified Confusion, Hubbub, and Order Scale (CHAOS-6) was utilized in this study. Descriptive, bivariate, and multivariate analyses were conducted. Results: The sample constituted of 208 (86%) men and 34 (14%) women. The average age was 55 years (SD = 11), and the age ranged between 24 and 96 years. Overall, 128 (52.9%) of the total post-MI survivors had highly chaotic lives. In multivariate analysis, younger age, lower household income, perceived financial insecurity, poor health status, and multiple comorbidities were related to the high chaos score, and these associations were statistically significant (p < 0.05). Conclusions: Highly chaotic lifestyles were prevalent in post-MI survivors. Demographic, health attributes, and socio-economic factors were important correlates of life chaos.
Anti-Adenoviral Activity of 2-(3-Chlorotetrahydrofuran-2-yl)-4-Tosyl-5-(Perfluoropropyl)-1,2,3-Triazole
Authors: Biliavska Liubov , Pankivska Yuliia , Povnitsa Olga , Zagorodnya Svitlana , Gudz Ganna , Shermolovich Yuriy
Published: November 2018

Background and objectives: A considerable increase in the levels of adenoviral diseases among both adults and children necessitate the development of effective methods for its prevention and treatment. The synthesis of the new fluorinated 1,2,3-triazoles, and the study of the mechanisms of their action, are promising for the development of efficient antiviral drugs of our time. Materials and Methods: Antiviral activity and cell cytotoxic effect of 2-(3-chlorotetrahydrofuran-2-yl)-4-tosyl-5-(perfluoropropyl)-1,2,3-triazole (G29) were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The influence of the compound on the infectivity of human adenovirus type 5 (HAdV-5) was carried out via the cytomorphology method. The influence of the compound on the cell cycle under a condition of adenovirus infection was studied using flow cytometric analysis of propidium iodide-stained cells. Results: It was found that G29 suppressed HAdV-5 reproduction by 50% in concentrations of 37 μg/mL. Furthermore, the compound reduced the titer of virus obtained de novo, and inhibited HAdV-5 inclusion bodies formation by 84–90%. The use of fluorinated compounds under the conditions of adenovirus infection decreased the number of apoptotic cells by 11% and the number of cells in S phase by 21–42% compared to the profile of infected cells. Conclusions: The fluorinated compound G29 showed moderate activity against HAdV-5 based on several mechanisms. It led to the normalization of the life cycle of cells infected with adenovirus to the level of non-infected cells and caused the obstruction of HAdV-5 reproduction, inducing the formation of non-infectious virus progeny.
Internet Mindfulness Meditation Intervention (IMMI) Improves Depression Symptoms in Older Adults
Authors: Wahbeh Helané
Published: November 2018

Background: Older adults have fewer physiological reserves and are more likely to be affected by stress. Mindfulness meditation has the potential to be an effective treatment for depression, but little research has been conducted on older adults. The primary objective of this study was to evaluate depression symptom changes in older adults (55–80 years old) taking an Internet Mindfulness Meditation Intervention (IMMI) compared to a waitlist control. The secondary aims were to collect data on pain, perceived stress, resilience, mindfulness, sleep quality, and spirituality. Methods: Fifty older adults were randomized to either the Internet Mindfulness Meditation Intervention, a six-week online intervention with daily home practice, or a waitlist control. Measures were collected at baseline, after the six-week intervention period, and again six weeks later after the waitlist participants completed IMMI. Adherence to home practice was objectively measured with iMINDr. Changes in outcomes for the IMMI and waitlist participants were compared. All participants who completed IMMI were then combined for a within-participant analysis. Results: Adherence to the intervention was low, likely due to a traumatic event in the local area of the participants. Compared to the waitlist participants, those in IMMI had improved depression symptoms (p < 0.00005), perceived stress (p = 0.0007), insomnia symptoms ((p = 0.0009), and pain severity (p = 0.05). In the within-participant analysis of all data before and after IMMI (i.e., those initially randomized to IMMI and waitlist participants who took it), we found improvements in depression symptoms (p = 0.0001), perceived stress (p = 0.0001), insomnia symptoms (p < 0.00005), pain interference (p = 0.003), and spirituality (p = 0.018). A seven-week follow-up after the original six-week IMMI program showed sustained improvements in the IMMI participants. Conclusions: IMMI improved depression and related symptoms compared to controls despite minimal support from study staff. IMMI offers a low-dose, low-cost, easily accessible mindfulness meditation intervention for older adults with depression symptoms.
Simulation of Crack Initiation and Propagation in the Crystals of a Beam Blank
Authors: Yang Gaiyan , Zhu Liguang , Chen Wei , Guo Gaoxiang , He Baomin
Published: November 2018

Surface cracking seriously affects the quality of beam blanks in continuous casting. To study the mechanism of surface crack initiation and propagation under beam blank mesoscopic condition, this study established a polycrystalline model using MATLAB. Based on mesoscopic damage mechanics, a full implicit stress iterative algorithm was used to simulate the crack propagation and the stress and strain of pores and inclusions of the polycrystalline model using ABAQUS software. The results show that the stress at the crystal boundary is much higher than that in the crystal, cracks occur earlier in the former than in the latter, and cracks extend along the direction perpendicular to the force. When a polycrystalline model with pores is subjected to tensile stress, a stress concentration occurs when the end of the pores is perpendicular to the stress direction, and the propagation and aggregation direction of the pores is basically perpendicular to the direction of the tensile stress. When a polycrystalline model with impurities is subjected to force, the stress concentrates around the impurity but the strain here is minimal, which leads to the crack propagating along the impurity direction. This study can provide theoretical guidance for controlling the generation of macroscopic cracks in beam blanks.
Endogenous Anti-Inflammatory Very-Long-Chain Dicarboxylic Acids: Potential Chemopreventive Lipids
Authors: Wood Paul L.
Published: November 2018

In a paradigm shift, cancer research efforts are being dedicated to the discovery of chemopreventive agents. The goal of this approach is to delay or prevent the progression of augmented cell division to established cancer. Research has focused on dietary supplements, drugs, and endogenous lipids that possess anti-inflammatory properties. We undertook a lipidomics analysis of potential endogenous anti-inflammatory/anti-proliferative lipids in human plasma. We performed high-resolution mass spectrometric lipidomics analyses of plasma samples from controls and patients with colorectal, kidney, pancreatic, glioblastoma, and breast cancers. We present evidence that endogenous very-long-chain dicarboxylic acids (VLCDCA) are anti-inflammatory lipids that possess chemopreventative properties. In a family of VLCDCAs, we characterized VLCDCA 28:4, which is decreased in the plasma of patients with colorectal, kidney, and pancreatic cancers. The structure of this biomarker was validated by derivatization strategies, synthesis of the analytical standard, and tandem mass spectrometry. Our data suggest that VLCDCA 28:4 may be a useful blood biomarker for a number of cancers and that resupplying this lipid, via a prodrug for example, may offer a new anti-inflammatory therapeutic strategy for delaying or preventing the progression of cancer and other inflammatory diseases.
Cutting Performance of Different Coated Micro End Mills in Machining of Ti-6Al-4V
Authors: Liang Zhiqiang , Gao Peng , Wang Xibin , Li Shidi , Zhou Tianfeng , Xiang Junfeng
Published: November 2018

Tool wear is a significant issue for the application of micro end mills. This can be significantly improved by coating materials on tool surfaces. This paper investigates the effects of different coating materials on tool wear in the micro milling of Ti-6Al-4V. A series of cutting experiments were conducted. The tool wear and workpiece surface morphology were investigated by analyzing the wear of the end flank surface and the total cutting edge. It was found that, without coating, serious tool wear and breakage occurred easily during milling. However, AlTiN-based and AlCrN-based coatings could highly reduce cutting edge chipping and flank wear. Specifically, The AlCrN-based coated mill presented less fracture resistance. For TiN coated micro end mill, only slight cutting edge chipping occurred. Compared with other types of tools, the AlTiN-based coated micro end mill could maximize tool life, bringing about an integrated cutting edges with the smallest surface roughness. In short, the AlTiN-based coating material is recommended for the micro end mill in the machining of Ti-6Al-4V.
Investigation on the I–V Kink Effect in Large Signal Modeling of AlGaN/GaN HEMTs
Authors: Mao Shuman , Xu Yuehang
Published: November 2018

The effect brought by the I–V kink effect on large signal performance of AlGaN/GaN high electron mobility transistors (HEMTs) was investigated in this paper. An improved compact model was proposed to accurately characterize the I–V kink effect. The bias dependence of the I–V kink effect has also been taken into consideration. AlGaN/GaN HEMTs with different gate width were utilized to validate the proposed model. Built on the proposed model, the effect brought by the I–V kink effect on large signal performance has been studied. Results show that the I–V kink effect will lead to the degradation of characteristics, including output power, gain, and power-added efficiency at the saturation region. Furthermore, the influence of the I–V kink effect was found to be related with the input power and the static bias point in this work. The time domain waveform and AC dynamic load line were used for validation of results based on simulation. The consequences of this paper will be useful for the optimization of practical circuit design.
Alkali-Activated Binder Based on Milled Antigorite
Authors: Kalinkina Elena V. , Gurevich Basya I. , Kalinkin Alexander M.
Published: November 2018

Antigorite is a very common rock-forming mineral and it is often present in mining wastes. Utilization of these wastes is a very important issue from the environmental point of view. A potential use for mining wastes is for the production of building materials. This study investigated the alkali activation of antigorite and antigorite-containing ore dressing tailings (AT) milled in a planetary ball mill in an air or CO2 atmosphere. The specific surface area, amorphisation, and dehydroxylation of milled antigorite and AT were examined, and their effect on the cementitious properties was investigated. Binders were prepared by mixing the milled antigorite or AT with liquid glass and curing at 20 ± 2 °C in dry (relative humidity of 65 ± 5%) or humid (relative humidity of 95 ± 5%) conditions for up to 28 days. Curing at dry conditions was found to produce binders with increased strengths. The compressive strength of the alkali-activated binder also increased with increased milling time. For AT milled in air for 4 min and cured in dry conditions for 28 days, the compressive strength was 49 MPa. The milling atmosphere (air or CO2) influenced the cementitious properties of the alkali activated binder to a small extent.
New Advances in General Biomedical Applications of PAMAM Dendrimers
Authors: Araújo Renan Vinicius de , Santos Soraya da Silva , Igne Ferreira Elizabeth , Giarolla Jeanine
Published: November 2018

Dendrimers are nanoscopic compounds, which are monodispersed, and they are generally considered as homogeneous. PAMAM (polyamidoamine) was introduced in 1985, by Donald A. Tomalia, as a new class of polymers, named ‘starburst polymers’. This important contribution of Professor Tomalia opened a new research field involving nanotechnological approaches. From then on, many groups have been using PAMAM for diverse applications in many areas, including biomedical applications. The possibility of either linking drugs and bioactive compounds, or entrapping them into the dendrimer frame can improve many relevant biological properties, such as bioavailability, solubility, and selectivity. Directing groups to reach selective delivery in a specific organ is one of the advanced applications of PAMAM. In this review, structural and safety aspects of PAMAM and its derivatives are discussed, and some relevant applications are briefly presented. Emphasis has been given to gene delivery and targeting drugs, as advanced delivery systems using PAMAM and an incentive for its use on neglected diseases are briefly mentioned.
2-(4-Methylsulfonylphenyl)pyrimidines as Prospective Radioligands for Imaging Cyclooxygenase-2 with PET—Synthesis, Triage, and Radiolabeling
Authors: Cortes-Salva Michelle Y. , Shrestha Stal , Singh Prachi , Morse Cheryl L. , Jenko Kimberly J. , Montero Santamaria Jose A. , Zoghbi Sami S. , Innis Robert B. , Pike Victor W.
Published: November 2018

Cyclooxygenase 2 (COX-2) is an inducible enzyme responsible for the conversion of arachidonic acid into the prostaglandins, PGG2 and PGH2. Expression of this enzyme increases in inflammation. Therefore, the development of probes for imaging COX-2 with positron emission tomography (PET) has gained interest because they could be useful for the study of inflammation in vivo, and for aiding anti-inflammatory drug development targeting COX-2. Nonetheless, effective PET radioligands are still lacking. We synthesized eleven COX-2 inhibitors based on a 2(4-methylsulfonylphenyl)pyrimidine core from which we selected three as prospective PET radioligands based on desirable factors, such as high inhibitory potency for COX-2, very low inhibitory potency for COX-1, moderate lipophilicity, and amenability to labeling with a positron-emitter. These inhibitors, namely 6-methoxy-2-(4-(methylsulfonyl)phenyl-N-(thiophen-2ylmethyl)pyrimidin-4-amine (17), the 6-fluoromethyl analogue (20), and the 6-(2-fluoroethoxy) analogue (27), were labeled in useful yields and with high molar activities by treating the 6-hydroxy analogue (26) with [11C]iodomethane, [18F]2-fluorobromoethane, and [d2-18F]fluorobromomethane, respectively. [11C]17, [18F]20, and [d2-18F]27 were readily purified with HPLC and formulated for intravenous injection. These methods allow these radioligands to be produced for comparative evaluation as PET radioligands for measuring COX-2 in healthy rhesus monkey and for assessing their abilities to detect inflammation.
Synthetic Methodologies to Gold Nanoshells: An Overview
Authors: Wang Yu-Chen , Rhéaume Éric , Lesage Frédéric , Kakkar Ashok
Published: November 2018

Gold nanostructures that can be synthetically articulated to adapt diverse morphologies, offer a versatile platform and tunable properties for applications in a variety of areas, including biomedicine and diagnostics. Among several conformational architectures, gold nanoshells provide a highly advantageous combination of properties that can be fine-tuned in designing single or multi-purpose nanomaterials, especially for applications in biology. One of the important parameters for evaluating the efficacy of gold nano-architectures is their reproducible synthesis and surface functionalization with desired moieties. A variety of methods now exist that allow fabrication and chemical manipulation of their structure and resulting properties. This review article provides an overview and a discussion of synthetic methodologies to a diverse range of gold nanoshells, and a brief summary of surface functionalization and characterization methods employed to evaluate their overall composition.
Pentafluorosulfanyl-containing Triclocarban Analogs with Potent Antimicrobial Activity
Authors: Pujol Eugènia , Blanco-Cabra Núria , Julián Esther , Leiva Rosana , Torrents Eduard , Vázquez Santiago
Published: November 2018

Concerns have been raised about the long-term accumulating effects of triclocarban, a polychlorinated diarylurea widely used as an antibacterial soap additive, in the environment and in human beings. Indeed, the Food and Drug Administration has recently banned it from personal care products. Herein, we report the synthesis, antibacterial activity and cytotoxicity of novel N,N′-diarylureas as triclocarban analogs, designed by reducing one or more chlorine atoms of the former and/or replacing them by the novel pentafluorosulfanyl group, a new bioisostere of the trifluoromethyl group, with growing importance in drug discovery. Interestingly, some of these pentafluorosulfanyl-bearing ureas exhibited high potency, broad spectrum of antimicrobial activity against Gram-positive bacterial pathogens, and high selectivity index, while displaying a lower spontaneous mutation frequency than triclocarban. Some lines of evidence suggest a bactericidal mode of action for this family of compounds.
Transcriptome Analysis of Gene Expression Patterns Potentially Associated with Premature Senescence in Nicotiana tabacum L.
Authors: Zhao Zhe , Li Yifan , Zhao Songchao , Zhang Jiawen , Zhang Hong , Fu Bo , He Fan , Zhao Mingqin , Liu Pengfei
Published: November 2018

Senescence affects the remobilization of nutrients and adaption of the plant to the environment. Combined stresses can result in premature senescence in plants which exist in the field. In this study, transcriptomic analysis was performed on mature leaves and leaves in three stages of premature senescence to understand the molecular mechanism. With progressive premature senescence, a declining chlorophyll (chl) content and an increasing malonaldehyde (MDA) content were observed, while plasmolysis and cell nucleus pyknosis occurred, mitochondria melted, thylakoid lamellae were dilated, starch grains in chloroplast decreased, and osmiophilic granules increased gradually. Moreover, in total 69 common differentially expressed genes (DEGs) in three stages of premature senescing leaves were found, which were significantly enriched in summarized Gene Ontology (GO) terms of membrane-bounded organelle, regulation of cellular component synthesis and metabolic and biosynthetic processes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that the plant hormone signal transduction pathway was significantly enriched. The common DEGs and four senescence-related pathways, including plant hormone signal transduction, porphyrin and chlorophyll metabolism, carotenoid biosynthesis, and regulation of autophagy were selected to be discussed further. This work aimed to provide potential genes signaling and modulating premature senescence as well as the possible dynamic network of gene expression patterns for further study.
The Many Ways by Which O-GlcNAcylation May Orchestrate the Diversity of Complex Glycosylations
Authors: Biwi James , Biot Christophe , Guerardel Yann , Vercoutter-Edouart Anne-Sophie , Lefebvre Tony
Published: November 2018

Unlike complex glycosylations, O-GlcNAcylation consists of the addition of a single N-acetylglucosamine unit to serine and threonine residues of target proteins, and is confined within the nucleocytoplasmic and mitochondrial compartments. Nevertheless, a number of clues tend to show that O-GlcNAcylation is a pivotal regulatory element of its complex counterparts. In this perspective, we gather the evidence reported to date regarding this connection. We propose different levels of regulation that encompass the competition for the nucleotide sugar UDP-GlcNAc, and that control the wide class of glycosylation enzymes via their expression, catalytic activity, and trafficking. We sought to better envision that nutrient fluxes control the elaboration of glycans, not only at the level of their structure composition, but also through sweet regulating actors.
Discovery of 3-Amino-2-Hydroxypropoxyisoflavone Derivatives as Potential Anti-HCV Agents
Authors: Lee Jin-Ching , Lin Chun-Kuang , Tseng Chin-Kai , Chen Yeh-Long , Tzeng Cherng-Chyi , Tseng Chih-Hua
Published: November 2018

Synthesis and anti-hepatitis C virus (anti-HCV) effects of certain 3-amino-2-hydroxy-propoxy isoflavone derivatives, 6a–i, were described. The known 3-(3,4-dimethoxyphenyl)-7-(oxiran-2-ylmethoxy)-4H-chromen-4-one (5) was reacted with substituted amines to give the desired isoflavone derivatives, 6a–i. Among them, 7-{3-[(3,4-dimethoxy-phenethyl)amino]-2-hydroxypropoxy}-3-(3,4-dimethoxyphenyl)-4H-chromen-4-one (6b) was the most active, exhibiting approximately 2-fold higher anti-HCV effects than standard antiviral drug ribavirin (EC50 of 6.53 vs. 13.16 μM). In addition, compound 6b was less cytotoxic than ribavirin. The selectivity index (SI) of 6b is approximately 2.6-fold higher than ribavirin. The compounds 6e, 6h, and 6i were also found to possess higher anti-HCV effects than ribavirin. Compound 6b was found to inhibit the HCV RNA expression in Ava5 cells in a dose-dependent manner; furthermore, we found that the antiviral mechanism of compounds 6b, 6e, 6h, and 6i gave rise to induction of HO-1 expression. With the HO-1 promoter-based analysis, we found compounds 6b, 6e, 6h, and 6i induced HO-1 expression through increasing Nrf-2 binding activity. Taken together, compound 6b may serve as a potential lead compound for developing novel anti-HCV agents.
Essential Oils from Humulus Lupulus scCO2 Extract by Hydrodistillation and Microwave-Assisted Hydrodistillation
Authors: Tyśkiewicz Katarzyna , Gieysztor Roman , Konkol Marcin , Szałas Jan , Rój Edward
Published: November 2018

Two different extraction methods were used for a comparative study of essential oils obtained from the Humulus lupulus scCO2 (sc-supercritical) extract: microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD). As a result, the best conditions for the maximum essential oil production were determined for the MAHD method at 335 W microwave power for 30 min at water to raw material ratio of 8:3. The obtained essential oils were enriched in β-myrcene in the amount of 74.13%–89.32% (wt%). Moreover, the first application for determination of the above-mentioned volatile compounds by supercritical fluid chromatography (SFC) with photo-diode array detection (PDA) is presented, which in comparison with gas chromatography coupled with mass spectrometry (GC-MS/MS) resulted in similar values for β-myrcene and α-humulene in obtained samples within less than 1 min.
Synthesis of Acridines through Alkyne Addition to Diarylamines
Authors: Berger Kristen E. , McCormick Grant M. , Jaye Joseph A. , Rozeske Christina M. , Fort Eric H.
Published: November 2018

A new synthesis of substituted acridines is achieved by palladium-catalyzed addition of terminal acetylenes between the aryl rings of bis(2-bromophenyl)amine. By including a diamine base and elevating the temperature, the reaction pathway favors the formation of acridine over a double Sonogashira reaction to form bis(tolan)amine. This method is demonstrated with several aryl-alkynes and alkyl-alkynes.
A Perspective on Reversibility in Controlled Polymerization Systems: Recent Progress and New Opportunities
Authors: Tang Houliang , Luan Yi , Yang Lu , Sun Hao
Published: November 2018

The field of controlled polymerization is growing and evolving at unprecedented rates, facilitating polymer scientists to engineer the structure and property of polymer materials for a variety of applications. However, the lack of degradability, particularly in vinyl polymers, is a general concern not only for environmental sustainability, but also for biomedical applications. In recent years, there has been a significant effort to develop reversible polymerization approaches in those well-established controlled polymerization systems. Reversible polymerization typically involves two steps, including (i) forward polymerization, which converts small monomers into macromolecule; and (ii) depolymerization, which is capable of regenerating original monomers. Furthermore, recycled monomers can be repolymerized into new polymers. In this perspective, we highlight recent developments of reversible polymerization in those controlled polymerization systems and offer insight into the promise and utility of reversible polymerization systems. More importantly, the current challenges and future directions to solve those problems are discussed. We hope this perspective can serve as an “initiator” to promote continuing innovations in this fairly new area.
Comparative Chemical Compositions of Fresh and Stored Vesuvian PDO “Pomodorino Del Piennolo” Tomato and the Ciliegino Variety
Authors: Manzo Nadia , Pizzolongo Fabiana , Meca Giuseppe , Aiello Alessandra , Marchetti Nicola , Romano Raffaele
Published: November 2018

The Vesuvian Piennolo cherry tomato (Lycopersicon esculentum Miller) (PdP) is an old and typical variety grown in the Campania region (Italy). PdP is referred to as a long-storage tomato due to its thick and coriaceous skin that allows long post-harvest storage and it has been granted Protected Designation of Origin (PDO) status since 2009. In this study, the chemical composition, focusing in particular on organic acids, antioxidant molecules and volatile compounds, were investigated in PdP and compared to another typical variety in Campania, the Ciliegino tomato (CIL). Chemical characterization was evaluated for both the CIL and PdP varieties during storage in the same environmental conditions until deterioration of 50% of the fruits; deterioration occurred in PdP after 6 months and in CIL tomatoes after 1 month. The results demonstrated variation in the chemical profiles of both varieties with storage length. Particularly, the PdP variety appears richer in antioxidants compounds (i.e., chlorogenic acids and lycopene) and organic acids (i.e., glutamic and malic acids) than does CIL. Additionally, both varieties display different profiles of volatile bioactive compounds and they are differently influenced by the storage time. The results indicate a typical chemical composition of this long-storage tomato closely linked to the geographic origin area.
New Metabolites from Endophytic Fungus Chaetomium globosum CDW7
Authors: Yan Wei , Cao Ling-Ling , Zhang Yang-Yang , Zhao Ran , Zhao Shuang-Shuang , Khan Babar , Ye Yong-Hao
Published: November 2018

Five metabolites including two new ones, prochaetoviridin A (1) and chaetoindolin A (2), were isolated from the endophytic fungus Chaetomium globosum CDW7. Compounds 1 and 2 were characterized as an isocoumarin and an indole alkaloid derivative, respectively, with their structures elucidated by comprehensive spectroscopic analyses including high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), NMR, and circular dichroism (CD) comparison. Compounds 3–5 were identified as chaetoviridin A, chaetoglobosin R, and chaetoglobosin T, respectively. Chaetoviridin A (3) exhibited antifungal activity against Sclerotinia sclerotiorum with an EC50 value of 1.97 μg/mL. In vivo test showed that 3 displayed a protective efficacy of 64.3% against rape Sclerotinia rot at the dosage of 200 μg/mL, comparable to that of carbendazim (69.2%).
Preparation of Functional Monomers as Precursors of Bioprobes from a Common Styrene Derivative and Polymer Synthesis
Authors: Hayama Riho , Koyama Tetsuo , Matsushita Takahiko , Hatano Ken , Matsuoka Koji
Published: November 2018

CM-Str (4-(Chloromethyl)styrene) was used as a useful starting material for the construction of a series of functional monomers. Substitution of the chlorine to the corresponding azide was performed, and the reduction of the azide proceeded smoothly to afford an aminostyrene, which was used as a common precursor for the preparation of functional monomers. Condensation of the amine with a fluorophore, biotin and carbohydrate was accomplished. Among the monomers, a carbohydrate monomer was polymerized with or without acrylamide as a model polymerization to yield the corresponding water-soluble glycopolymers, and biological evaluations of the glycopolymers for a lectin, and wheat germ agglutinin (WGA), were carried out on the basis of the fluorescence change of tryptophan in the WGA.
Biochemical and Functional Characterization of Anthocyanidin Reductase (ANR) from Mangifera indica L.
Authors: Tan Lin , Wang Mei , Kang Youfa , Azeem Farrukh , Zhou Zhaoxi , Tuo Decai , María Preciado Rojo Lina , Khan Ikhlas A. , Pan Zhiqiang
Published: November 2018

Mango (Mangifera indica L.) is abundant in proanthocyanidins (PAs) that are important for human health and plant response to abiotic stresses. However, the molecular mechanisms involved in PA biosynthesis still need to be elucidated. Anthocyanidin reductase (ANR) catalyzes a key step in PA biosynthesis. In this study, three ANR cDNAs (MiANR1-1,1-2,1-3) were isolated from mango, and expressed in Escherichia coli. In vitro enzyme assay showed MiANR proteins convert cyanidin to their corresponding flavan-3-ols, such as (−)-catechin and (−)-epicatechin. Despite high amino acid similarity, the recombinant ANR proteins exhibited differences in enzyme kinetics and cosubstrate preference. MiANR1-2 and MiANR1-3 have the same optimum pH of 4.0 in citrate buffer, while the optimum pH for MiANR1-1 is pH 3.0 in phosphate buffer. MiANR1-1 does not use either NADPH or NADH as co-substrate while MiANR1-2/1-3 use only NADPH as co-substrate. MiANR1-2 has the highest Km and Vmax for cyanidin, followed by MiANR1-3 and MiANR1-1. The overexpression of MiANRs in ban mutant reconstructed the biosynthetic pathway of PAs in the seed coat. These data demonstrate MiANRs can form the ANR pathway, leading to the formation of two types of isomeric flavan-3-ols and PAs in mango.
Synthetic Evaluation of Standard and Microwave-Assisted Solid Phase Peptide Synthesis of a Long Chimeric Peptide Derived from Four Plasmodium falciparum Proteins
Authors: Varela Yahson F. , Vanegas Murcia Magnolia , Patarroyo Manuel Elkin
Published: November 2018

An 82-residue-long chimeric peptide was synthesised by solid phase peptide synthesis (SPPS), following the Fmoc protocol. Microwave (MW) radiation-assisted synthesis was compared to standard synthesis using low loading (0.20 mmol/g) of polyethylene glycol (PEG) resin. Similar synthetic difficulties were found when the chimeric peptide was obtained via these two reaction conditions, indicating that such difficulties were inherent to the sequence and could not be resolved using MW; by contrast, the number of coupling cycles and total reaction time became reduced whilst crude yield and percentage recovery after purification were higher for MW radiation-assisted synthesis.