bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Design of Recycled Ethylene Propylene Diene Monomer Rubber Modified Epoxy Based Composites Reinforced with Alumina Fiber: Fracture Behavior and Damage Analyses
Authors: Irez Alaeddin Burak , Zambelis Georges , Bayraktar Emin
Published: August 2019

This study proposes a new design of lightweight and cost-efficient composite materials for the automotive industry using recycled fresh scrap rubbers (EPDM (ethylene propylene diene monomer) rubbers), epoxy resin and alumina (Al2O3) fibers (AF). Three-point bending tests were conducted to investigate fundamental mechanical characteristics and then experimentally obtained moduli were compared with a modified Halpin–Tsai model. In addition, tests were carried out to study the fracture characteristics of the composites. Then, a practical numerical study was carried out to observe the evolution of the strain energy release rate along the crack front. Mechanical test results showed that the reinforcement with AF improved the fracture toughness of these novel composites for low rubber contents. Besides, increasing recycled EPDM rubber content degraded the mechanical resistance and strain at break of the composites. Moreover, numerical studies indicated that energy release rate showed some variations along the specimen thickness. Toughening mechanisms were evaluated by scanning electron microscope (SEM) fractography. Typical toughening mechanisms observed were fiber bridging and shear yielding. By considering the advantageous effects of AF on the novel composites and cost efficiency under favor of recycled rubbers, these composites are promising candidates to manufacture the various components in automotive industry.
A New Class of Iterative Processes for Solving Nonlinear Systems by Using One Divided Differences Operator
Authors: Cordero Alicia , Jordán Cristina , Sanabria Esther , Torregrosa Juan R.
Published: August 2019

In this manuscript, a new family of Jacobian-free iterative methods for solving nonlinear systems is presented. The fourth-order convergence for all the elements of the class is established, proving, in addition, that one element of this family has order five. The proposed methods have four steps and, in all of them, the same divided difference operator appears. Numerical problems, including systems of academic interest and the system resulting from the discretization of the boundary problem described by Fisher’s equation, are shown to compare the performance of the proposed schemes with other known ones. The numerical tests are in concordance with the theoretical results.
Iterative Algorithms for Split Common Fixed Point Problem Involved in Pseudo-Contractive Operators without Lipschitz Assumption
Authors: Chen Jinzuo , Postolache Mihai , Zhu Li-Jun
Published: August 2019

Two iterative algorithms are suggested for approximating a solution of the split common fixed point problem involved in pseudo-contractive operators without Lipschitz assumption. We prove that the sequence generated by the first algorithm converges weakly to a solution of the split common fixed point problem and the second one converges strongly. Moreover, the sequence { x n } generated by Algorithm 3 strongly converges to z = proj S 0 , which is the minimum-norm solution of problem (1). Numerical examples are included.
Cryptanalysis of an Authentication Scheme Using an Identity Based Generalized Signcryption
Authors: Waheed Abdul , Umar Arif Iqbal , Din Nizamud , Amin Noor Ul , Abdullah Saleem , Kumam Poom
Published: August 2019

Secure data transmission is a challenging issue in modern data communication. ID based generalized signcryption is a cost effective security primitive which provides authentication or confidentiality, or jointly confidentiality and authentication. Wei’s proposed an ID based generalized signcryption scheme for authentication and confidentiality of big data in a standard model, claiming that their scheme holds the security of indistinguishability against adaptive chosen-ciphertext attacks and existential unforgeability against adaptive chosen message attacks. In this paper, we analyzed Wei’s scheme by launching security attacks on the scheme to check its validity. As a result, it became clear and proved that the master secret key generated in the scheme is compromisable. Similarly, the mentioned scheme does not hold the security of indistinguishability against adaptive chosen-ciphertext attacks and existential unforgeability against adaptive chosen message attacks. Consequently, Wei’s schemes is prone to attacks and is insecure.
Complete Ensemble Empirical Mode Decomposition on FPGA for Condition Monitoring of Broken Bars in Induction Motors
Authors: Valtierra-Rodriguez Martin , Amezquita-Sanchez Juan , Garcia-Perez Arturo , Camarena-Martinez David
Published: August 2019

Empirical mode decomposition (EMD)-based methods are powerful digital signal processing techniques because they do not need a priori information of the target signal due to their intrinsic adaptive behavior. Moreover, they can deal with non-linear and non-stationary signals. This paper presents the field programmable gate array (FPGA) implementation for the complete ensemble empirical mode decomposition (CEEMD) method, which is applied to the condition monitoring of an induction motor. The CEEMD method is chosen since it overcomes the performance of EMD and EEMD (ensemble empirical mode decomposition) methods. As a first application of the proposed FPGA-based system, the proposal is used as a processing technique for feature extraction in order to detect and classify broken rotor bar faults in induction motors. In order to obtain a complete online monitoring system, the feature extraction and classification modules are also implemented on the FPGA. Results show that an average effectiveness of 96% is obtained during the fault detection.
Probability Functions on Posets
Authors: Kim Jae , Kim Hee , Neggers Joseph
Published: August 2019

In this paper, we define the notion of a probability function on a poset which is similar to the probability function discussed on d-algebras, and obtain three probability functions on posets. Moreover, we define a probability realizer of a poset, and we provide some examples to describe its role for the standard probability function. We apply the notion of a probability function to the ordered plane and obtain three probability functions on it.
Hopf Bifurcation of Heated Panels Flutter in Supersonic Flow
Authors: Cao Li-Na , Yao Guofeng
Published: August 2019

A differential equation of panel vibration in supersonic flow is established on the basis of the thin-plate large deflection theory under the assumption of a quasi-steady temperature field. The equation is dimensionless, and the derivation of its second-order Galerkin discretization yields a four-dimensional system. The algebraic criterion of the Hopf bifurcation is applied to study the motion stability of heated panels in supersonic flow. We provide a supplementary explanation for the proof process of a theorem, and analytical expressions of flutter dynamic pressure and panel vibration frequencies are derived. The conclusion is that the algebraic criterion of Hopf bifurcation can be applied in high-dimensional problems with many parameters. Moreover, the computational intensity of the method established in this work is less than that of conventional eigenvalue computation methods using parameter variation.
Synthesis and Antitumor Activity Evaluation of Compounds Based on Toluquinol
Authors: Cheng-Sánchez Iván , Torres-Vargas José A. , Martínez-Poveda Beatriz , Guerrero-Vásquez Guillermo A. , Medina Miguel Ángel , Sarabia Francisco , Quesada Ana R.
Published: August 2019

Encouraged by the promising antitumoral, antiangiogenic, and antilymphangiogenic properties of toluquinol, a set of analogues of this natural product of marine origin was synthesized to explore and evaluate the effects of structural modifications on their cytotoxic activity. We decided to investigate the effects of the substitution of the methyl group by other groups, the introduction of a second substituent, the relative position of the substituents, and the oxidation state. A set of analogues of 2-substituted, 2,3-disubstituted, and 2,6-disubstituted derived from hydroquinone were synthesized. The results revealed that the cytotoxic activity of this family of compounds could rely on the hydroquinone/benzoquinone part of the molecule, whereas the substituents might modulate the interaction of the molecule with their targets, changing either its activity or its selectivity. The methyl group is relevant for the cytotoxicity of toluquinol, since its replacement by other groups resulted in a significant loss of activity, and in general the introduction of a second substituent, preferentially in the para position with respect to the methyl group, was well tolerated. These findings provide guidance for the design of new toluquinol analogues with potentially better pharmacological properties.
Total Syntheses and Preliminary Biological Evaluation of Brominated Fascaplysin and Reticulatine Alkaloids and Their Analogues
Authors: Zhidkov Maxim E. , Smirnova Polina A. , Tryapkin Oleg A. , Kantemirov Alexey V. , Khudyakova Yuliya V. , Malyarenko Olesya S. , Ermakova Svetlana P. , Grigorchuk Valeria P. , Kaune Moritz , von Amsberg Gunhild , Dyshlovoy Sergey A.
Published: August 2019

A simple approach toward the synthesis of the marine sponge derived pigment fascaplysin was used to obtain the marine alkaloids 3-bromofascaplysin and 3,10-dibromofascaplysin. These compounds were used for first syntheses of the alkaloids 14-bromoreticulatate and 14-bromoreticulatine. Preliminary bioassays showed that 14-bromoreticulatine has a selective antibiotic (to Pseudomonas aeruginosa) activity and reveals cytotoxicity toward human melanoma, colon, and prostate cancer cells. 3,10-Dibromofascaplysin was able to target metabolic activity of the prostate cancer cells, without disrupting cell membrane’s integrity and had a wide therapeutic window amongst the fascaplysin alkaloids.
Opioids Preconditioning Upon Renal Function and Ischemia-Reperfusion Injury: A Narrative Review
Authors: Palomino Julio , Echavarria Raquel , Franco-Acevedo Adriana , Moreno-Carranza Bibiana , Melo Zesergio
Published: August 2019

Kidneys have an important role in regulating water volume, blood pressure, secretion of hormones and acid-base and electrolyte balance. Kidney dysfunction derived from acute injury can, under certain conditions, progress to chronic kidney disease. In the late stages of kidney disease, treatment is limited to replacement therapy: Dialysis and transplantation. After renal transplant, grafts suffer from activation of immune cells and generation of oxidant molecules. Anesthetic preconditioning has emerged as a promising strategy to ameliorate ischemia reperfusion injury. This review compiles some significant aspects of renal physiology and discusses current understanding of the effects of anesthetic preconditioning upon renal function and ischemia reperfusion injury, focusing on opioids and its properties ameliorating renal injury. According to the available evidence, opioid preconditioning appears to reduce inflammation and reactive oxygen species generation after ischemia reperfusion. Therefore, opioid preconditioning represents a promising strategy to reduce renal ischemia reperfusion injury and, its application on current clinical practice could be beneficial in events such as acute renal injury and kidney transplantation.
Hepatocellular Carcinoma: Molecular Mechanisms and Targeted Therapies
Authors: Alqahtani Ali , Khan Zubair , Alloghbi Abdurahman , S. Said Ahmed Tamer , Ashraf Mushtaq , M. Hammouda Danae
Published: August 2019

Hepatocellular carcinoma (HCC) is one of the most common and lethal malignant tumors worldwide. HCC is a complex process that is associated with several etiological factors, which in turn result in aberrant activation of different cellular and molecular pathways and the disruption of balance between activation and inactivation of protooncogenes and tumor suppressor genes, respectively. Since HCC most often occurs in the setting of a diseased or cirrhotic liver and most of the patients are diagnosed at the late stage of disease, prognosis is generally poor. At present, limited treatment options with marginal clinical benefits are available. Systemic therapy, particularly in the form of conventional cytotoxic drugs, are generally ineffective. In recent years, molecular-targeted therapies have been clinically used to treat various cancers, including liver cancer. This approach inhibits the growth of tumor cells by interfering with molecules that are involved in carcinogenesis, which makes it more selective and specific than cytotoxic chemotherapy. Many clinical trials have been carried out while using molecular targeted drugs in advanced HCC with many more in progress. The clinical trials in HCC to date have evaluated a single-targeted therapy alone, or two or more targeted therapies in parallel. The aim of this review is to provide insight of various molecular mechanisms, leading to HCC development and progression, and also the range of experimental therapeutics for patients with advanced HCC. The review will summarize different clinical trials data the successes and failures of these treatments, as well as the most effective and approved drugs designed against HCC.
The Extent of Extemporaneous Preparation and Regulatory Framework of Extemporaneous Compounding in Latvia
Authors: Kiseļova Olga , Mauriņa Baiba , Šidlovska Venta , Zvejnieks Jānis
Published: August 2019

Background and objectives: Extemporaneous preparations are pharmaceutical preparations individually prepared for a specific patient or patient group, but also high-risk products accompanied by doubts regarding their safety and quality. Legislation regulating the compounding of extemporaneous preparations is not harmonized among European countries. This problem is partially resolved by Resolution CM/Res(2016)1 on quality and safety assurance requirements for medicinal products prepared in pharmacies for the special needs of patients. In order to understand the relevance of extemporaneous compounding in Latvia and the fulfillment of the abovementioned resolution’s requirements, it is essential to get information about the volume and breakdown of sales of extemporaneous medicinal products in community pharmacies. The purpose of this survey is to identify the sales volume of extemporaneous preparations in community pharmacies in Latvia in 2017 by analyzing unpublished data of the State Agency of Medicines (SAM), as well as comparing Latvian laws with the requirements of the resolution. Materials and Methods: A separate Microsoft Excel spreadsheet was prepared for each statistical region in order to summarize the unpublished information of SAM on the turnover of extemporaneous preparations in 2017 in all Latvian statistical regions. In order to compare the regulatory framework in Latvia with the resolution, the Latvian Pharmaceutical Law and the Cabinet of Ministers Regulations regulating prescription, compounding and control of extemporaneous preparations in community pharmacies were analyzed. Results: Only 280 of 384 pharmacies submitted a report of sales of extemporaneous preparations for 2017 to the SAM. These pharmacies represented all Latvian statistical regions. Extemporaneous preparations were mostly sold in Riga (78.93%). The Latvian regulation does not include all paragraphs of the resolution. Most of the paragraphs of the resolution are described in Latvian regulatory enactments only partially. Conclusions: The total number of compounding pharmacies evidence that the service is needed. Latvian example highlights a necessity for European Union countries to compare their national legislation with the requirements of the resolution’s last version and, if necessary, implement relevant amendments.
Lack of Group Support and Burnout Syndrome in Workers of the State Security Forces and Corps: Moderating Role of Neuroticism
Authors: Farfán Jesús , Peña Marta , Topa Gabriela
Published: August 2019

Background and Objectives: This research analyzes the relationship between the lack of group support and burnout syndrome in workers of the State Security Forces and Corps, considering the role of personality traits in this relationship. In particular, it is hypothesized that neuroticism will moderate this relationship. Materials and Methods: Participants were 237 workers from the State Security Forces and Corps dedicated to tasks of citizen security. Results: The results show that neuroticism moderates the relationship between lack of group support and the three components of the burnout syndrome: emotional exhaustion, depersonalization, and personal fulfillment. Conclusions: The findings are discussed, suggesting intervention strategies for the improvement of the agents’ personal well-being.
Accelerated Ferrite-to-Austenite Transformation During Intercritical Annealing of Medium-Manganese Steels Due to Cold-Rolling
Authors: Mueller Josh , Matlock David , Speer John , De Moor Emmanuel
Published: August 2019

Prior cold deformation is known to influence the ferrite-to-austenite (α → γ) transformation in medium-manganese (Mn) steels that occurs during intercritical annealing. In the present study, a 7Mn steel with ultra-low residual carbon content and varying amounts of prior cold deformation was intercritically annealed using various heating rates in a dilatometer. The study was conducted using an ultra-low carbon steel so that assessments of austenite formation during intercritical annealing would reflect the effects of cold deformation on the α → γ transformation and Mn partitioning and not effect cementite formation and dissolution or paraequilibrium partitioning induced austenite growth from carbon. Increasing prior cold deformation was found to decrease the Ac1 temperature, increase austenite volume fraction during intercritical annealing, and increase the amount of austenite nucleation sites. Phase field simulations were also conducted in an attempt to simulate the apparent accelerated α → γ transformation with increasing prior cold deformation. Mechanisms for accelerated α → γ transformation explored with phase field simulations included an increase in the amount of austenite nucleation sites and an increased Mn diffusivity in ferrite. Simulations with different amounts of austenite nucleation sites and Mn diffusivity in ferrite predicted significant changes in the austenite volume fraction during intercritical annealing.
Influence of the Processing Method on the Properties of Ti-23 at.% Mo Alloy
Authors: Sochacka Patrycja , Miklaszewski Andrzej , Kowalski Kamil , Jurczyk Mieczyslaw
Published: August 2019

In this paper, binary β type Ti-23 at.% Mo alloys were obtained by arc melting as well as by mechanical alloying and powder metallurgical process with cold powder compaction and sintering or, interchangeably, hot pressing. The influence of the synthesis method on the microstructure and properties of bulk alloys were studied. The produced materials were characterized by an X-ray diffraction technique, scanning electron microscopy and chemical composition determination. Young’s modulus was evaluated with nanoindentation testing method based on the Oliver and Pharr approach. The mechanically alloyed Ti-23 at.% Mo powders, after inductively hot-pressed at 800 °C for 5 min, allowed the formation of single Ti(β) phase alloy. In this case, Young’s modulus and Vickers hardness were 127 GPa and 454 HV0.3, respectively. Among the examined materials, the porous (55%) single-phase scaffold showed the lowest indentation modulus (69.5 GPa). Analytical approach performed in this work focuses also on the surface properties. The estimation includes the corrosion resistance analyzed in the potentiodynamic test, and also some wettability properties as a contact angle, and surface free energy values measured in glycerol and diiodomethane testing fluids. Additionally, surface modification of processed material by micro-arc oxidation and electrophoretic deposition on the chosen samples was investigated. Proposed procedures led to the formation of apatite and fluorapatite layers, which influence both the corrosion resistance and surface wetting properties in comparison to unmodified samples. The realized research shows that a single-phase ultrafine-grained Ti-23 at.% Mo alloy for medical implant applications can be synthesized at a temperature lower than the transition point by the application of hot pressing of mechanically alloyed powders. The material processing, that includes starting powder preparation, bulk alloy transformation, and additional surface treatment functionalization, affect final properties by the obtained phase composition and internal structure.
An Improved 4H-SiC MESFET with a Partially Low Doped Channel
Authors: Jia Hujun , Tong Yibo , Li Tao , Zhu Shunwei , Liang Yuan , Wang Xingyu , Zeng Tonghui , Yang Yintang
Published: August 2019

An improved 4H-SiC metal semiconductor field effect transistor (MESFET) based on the double-recessed MESFET (DR-MESFET) for high power added efficiency (PAE) is designed and simulated in this paper and its mechanism is explored by co-simulation of ADS and ISE-TCAD software. This structure has a partially low doped channel (PLDC) under the gate, which increases the PAE of the device by decreasing the absolute value of the threshold voltage (Vt), gate-source capacitance (Cgs) and saturation current (Id). The simulated results show that with the increase of H, the PAE of the device increases and then decreases when the value of NPLDC is low enough. The doping concentration and thickness of the PLDC are respectively optimized to be NPLDC = 1 × 1015 cm−3 and H = 0.15 μm to obtain the best PAE. The maximum PAE obtained from the PLDC-MESFET is 43.67%, while the PAE of the DR-MESFET is 23.43%; the optimized PAE is increased by 86.38%.
Three-Dimensional Laser Printing of Macro-Scale Glass Objects at a Micro-Scale Resolution
Authors: Wang Peng , Chu Wei , Li Wenbo , Tan Yuanxin , Liu Fang , Wang Min , Qi Jia , Lin Jintian , Zhang Fangbo , Wang Zhanshan , Cheng Ya
Published: August 2019

Three-dimensional (3D) printing has allowed for the production of geometrically complex 3D objects with extreme flexibility, which is currently undergoing rapid expansion in terms of materials, functionalities, as well as areas of application. When attempting to print 3D microstructures in glass, femtosecond laser-induced chemical etching (FLICE)—which is a subtractive 3D printing technique—has proved itself a powerful approach. Here, we demonstrate the fabrication of macro-scale 3D glass objects of large heights up to ~3.8 cm with an identical lateral and longitudinal feature size of ~20 μm. The remarkable accomplishment is achieved by revealing an unexplored regime in the interaction of ultrafast laser pulses with fused silica, which results in depth-insensitive focusing of the laser pulses inside fused silica.
A Transcriptional Activator of Ascorbic Acid Transport in Streptococcus pneumoniae Is Required for Optimal Growth in Endophthalmitis in a Strain-Dependent Manner
Authors: Benton Angela H. , Jackson Mary Darby , Wong Sandy M. , Dees Justine L. , Akerley Brian J. , Marquart Mary E.
Published: August 2019

Streptococcus pneumoniae is among the top causes of bacterial endophthalmitis, an infectious disease of the intraocular fluids. The mechanisms by which S. pneumoniae grows and thrives in the intraocular cavity are not well understood. We used a bacterial genome-wide assessment tool (transposon insertion site sequencing) to determine genes essential for S. pneumoniae growth in vitreous humor. The results indicated that an ascorbic acid (AA) transport system subunit was important for growth. We created an isogenic gene deletion mutant of the AA transcriptional activator, ulaR2, in 2 strains of S. pneumoniae. Growth curve analysis indicated that ulaR2 deletion caused attenuated growth in vitro for both strains. However, in vivo vitreous humor infection in rabbits with either strain determined that ulaR2 was necessary for growth in one strain but not the other. These results demonstrate that ulaR2 may be important for fitness during S. pneumoniae endophthalmitis depending on the background of the strain.
A Coordinated Response at The Transcriptome and Interactome Level is Required to Ensure Uropathogenic Escherichia coli Survival during Bacteremia
Authors: de Groot Natalia Sanchez , Torrent Burgas Marc
Published: August 2019

Localized infections or disruption of the skin barrier can enable the entry of bacteria into the bloodstream, possibly leading to acute inflammation and sepsis. There is currently no holistic view on how bacteria can survive and spread in the bloodstream. In this context, we combined transposon mutagenesis, gene-expression profiling and a protein interaction network analysis to examine how uropathogenic Escherichia coli can proliferate in blood. Our results indicate that, upon migration from the urea to serum, E. coli reacts to the osmolarity difference, triggering a transcriptomic response in order to express survival genes. The proteins codified by these genes are precisely organized at the interactome level and specifically target short linear motifs located in disordered regions of host proteins. Such a coordinated response helps to explain how bacteria can adapt to and survive environmental changes within the host. Overall, our results provide a general framework for the study of bacteremia and reveal new targets for potential study as novel antimicrobials.
Mechanochemical Preparation of Slow Release Fertilizer Based on Glauconite–Urea Complexes
Authors: Rudmin Maxim , Abdullayev Elshan , Ruban Alexey , Buyakov Ales , Soktoev Bulat
Published: August 2019

We investigated the mechanochemical synthesis of complex slow release fertilizers (SRF) derived from glauconite. We studied the effectiveness of the mechanical intercalation of urea into glauconite using planetary and ring mills. The potassium-nitric complex SRFs were synthesized via a mechanochemical method mixing glauconite with urea in a 3:1 ratio. The obtained composites were analyzed using X-ray diffraction analysis, scanning electron microscopy, X-ray fluorescence analysis, and infrared spectroscopy. The results show that as duration of mechanochemical activation increases, the mineralogical, chemical, and structural characteristics of composites change. Essential modifications associated with a decrease in absorbed urea and the formation of microcrystallites were observed when the planetary milling time increased from 5 to 10 min and the ring milling from 15 to 30 min. Complete intercalation of urea into glauconite was achieved by 20 min grinding in a planetary mill or 60 min in a ring mill. Urea intercalation in glauconite occurs much faster when using a planetary mill compared to a ring mill.
Age and Origin of Silicocarbonate Pegmatites of the Adirondack Region
Authors: Chiarenzelli Jeffrey , Lupulescu Marian , Robinson George , Bailey David , Singer Jared
Published: August 2019

Silicocarbonate pegmatites from the southern Grenville Province have provided exceptionally large crystal specimens for more than a century. Their mineral parageneses include euhedral calc–silicate minerals such as amphibole, clinopyroxene, and scapolite within a calcite matrix. Crystals can reach a meter or more in long dimension. Minor and locally abundant phases reflect local bedrock compositions and include albite, apatite, perthitic microcline, phlogopite, zircon, tourmaline, titanite, danburite, uraninite, sulfides, and many other minerals. Across the Adirondack Region, individual exposures are of limited aerial extent (<10,000 m2), crosscut metasedimentary rocks, especially calc–silicate gneisses and marbles, are undeformed and are spatially and temporally associated with granitic pegmatites. Zircon U–Pb results include both Shawinigan (circa 1165 Ma) and Ottawan (circa 1050 Ma) intrusion ages, separated by the Carthage-Colton shear zone. Those of Shawinigan age (Lowlands) correspond with the timing of voluminous A-type granitic magmatism, whereas Ottawan ages (Highlands) are temporally related to orogenic collapse, voluminous leucogranite and granitic pegmatite intrusion, iron and garnet ore development, and pervasive localized hydrothermal alteration. Inherited zircon, where present, reflects the broad range of igneous and detrital ages of surrounding rocks. Carbon and oxygen isotopic ratios from calcite plot within a restricted field away from igneous carbonatite values to those of typical sedimentary carbonates and local marbles. Collectively, these exposures represent a continuum between vein-dyke and skarn occurrences involving the anatexis of metasedimentary country rocks. Those of Ottawan age can be tied to movement and fluid flow along structures accommodating orogenic collapse, particularly the Carthage-Colton shear zone.
CO2 Adsorption of Materials Synthesized from Clay Minerals: A Review
Authors: Chouikhi Nesrine , Cecilia Juan Antonio , Vilarrasa-García Enrique , Besghaier Sabrine , Chlendi Mohamed , Franco Duro Francisco Ignacio , Rodriguez Castellon Enrique , Bagane Mohamed
Published: August 2019

The aim of this work is to make a brief review of the adsorption of CO2 on modified clay minerals. Previous researchers have used different clay modifications, either by making changes in the structure by a reaction with another product or by the addition of a catalyst to improve their CO2 adsorption capacity. In order to obtain high values of CO2 uptake, some researchers have been incorporated amines-speices such as (3-aminopropyl)triethoxysilane (APTES), tetraethylenepentamine (TEPA) and a branched polyethylenimine (PEI) by grafting or impregnation. The synthesis of an adsorbent from mineral clays can generate an increase in its porosity and in its textural properties. These investigations differ in a number of factors such as the kind of clay, the operating conditions, y and the nature of the impregnated compound. The role of these factors in the CO2 adsorption capacity will be considered in detail in this review.
Untargeted Metabolomic Profile for the Detection of Prostate Carcinoma—Preliminary Results from PARAFAC2 and PLS–DA Models
Authors: Amante Eleonora , Salomone Alberto , Alladio Eugenio , Vincenti Marco , Porpiglia Francesco , Bro Rasmus
Published: August 2019

Prostate-specific antigen (PSA) is the main biomarker for the screening of prostate cancer (PCa), which has a high sensibility (higher than 80%) that is negatively offset by its poor specificity (only 30%, with the European cut-off of 4 ng/mL). This generates a large number of useless biopsies, involving both risks for the patients and costs for the national healthcare systems. Consequently, efforts were recently made to discover new biomarkers useful for PCa screening, including our proposal of interpreting a multi-parametric urinary steroidal profile with multivariate statistics. This approach has been expanded to investigate new alleged biomarkers by the application of untargeted urinary metabolomics. Urine samples from 91 patients (43 affected by PCa; 48 by benign hyperplasia) were deconjugated, extracted in both basic and acidic conditions, derivatized with different reagents, and analyzed with different gas chromatographic columns. Three-dimensional data were obtained from full-scan electron impact mass spectra. The PARADISe software, coupled with NIST libraries, was employed for the computation of PARAFAC2 models, the extraction of the significative components (alleged biomarkers), and the generation of a semiquantitative dataset. After variables selection, a partial least squares–discriminant analysis classification model was built, yielding promising performances. The selected biomarkers need further validation, possibly involving, yet again, a targeted approach.
An Original HPLC Method with Coulometric Detection to Monitor Hydroxyl Radical Generation via Fenton Chemistry
Authors: Catapano Maria Carmen , Protti Michele , Fontana Tommaso , Mandrioli Roberto , Mladěnka Přemysl , Mercolini Laura
Published: August 2019

Hydroxyl radicals (•OH) can be generated via Fenton chemistry catalyzed by transition metals. An in vitro Fenton system was developed to test both the inhibition and stimulation of •OH formation, by monitoring salicylate aromatic hydroxylation derivatives as markers of •OH production. The reaction was optimized with either iron or copper, and target analytes were determined by means of an original HPLC method coupled to coulometric detection. The method granted good sensitivity and precision, while method applicability was tested on antioxidant compounds with and without chelating properties in different substance to metal ratios. This analytical approach shows how Fenton’s reaction can be monitored by HPLC coupled to coulometric detection, as a powerful tool for studying molecules′ redox behavior.
Development of 11-DGA-3-O-Gal-Modified Cantharidin Liposomes for Treatment of Hepatocellular Carcinoma
Authors: Zhou Lili , Zou Manshu , Zhu Kun , Ning Shuangcheng , Xia Xinhua
Published: August 2019

Background: Liver cancer is a common malignant tumor worldwide, and its morbidity and mortality increase each year. The disease has a short course and high mortality, making it a serious threat to human health. Purpose: The objective of this study was to create novel liver-targeting nanoliposomes to encapsulate cantharidin (CTD) as a potential treatment for hepatic carcinoma. Methods: 3-Galactosidase-30-stearyl deoxyglycyrrhetinic acid (11-DGA-3-O-Gal)-modified liposomes (11-DGA-3-O-Gal-CTD-lip) for the liver-targeted delivery of CTD were prepared via the film-dispersion method and characterized. In vitro analyses of the effects on cellular cytotoxicity, cell migration, cell cycle, and cell apoptosis were carried out and an in vivo pharmacokinetics study and tissue distribution analysis were performed. Results: Compared with unmodified liposomes (CTD-lip), 11-DGA-3-O-Gal-CTD-lip showed higher cytotoxicity and increased the inhibition of HepG2 cell migration, but they did not increase the apoptotic rate of cells. The inhibition mechanism of 11-DGA-3-O-Gal-CTD-lip on hepatocellular carcinoma was partly through cell cycle arrest at the S phase. Analysis of pharmacokinetic parameters indicated that 11-DGA-3-O-Gal-CTD-lip were eliminated more rapidly than CTD-lip. Regarding tissue distribution, the targeting efficiency of 11-DGA-3-O-Gal-CTD-lip to the liver was (41.15 ± 3.28)%, relative targeting efficiency was (1.53 ± 0.31)%, relative uptake rate was( 1.69 ± 0.37)%, and peak concentration ratio was (2.68 ± 0.12)%. Conclusion: 11-DGA-3-O-Gal-CTD-lip represent a promising nanocarrier for the liver-targeted delivery of antitumor drugs to treat hepatocellular carcinoma.
A Comparative Study on the Phenolic Composition and Biological Activities of Morus alba L. Commercial Samples
Authors: Polumackanycz Milena , Sledzinski Tomasz , Goyke Elzbieta , Wesolowski Marek , Viapiana Agnieszka
Published: August 2019

Morus alba L. (white mulberry) has been commonly used as a functional food and for medicinal purposes. Hence, the aim of the study was to compare the phenolic profile of white mulberry commercial samples in relation to their antioxidant potential and acetylcholinesterase (AChE) inhibitory activity. It is of interest to determine whether herbal products originating from different commercial sources differ in their phenolic profiles. For this purpose, a simple and rapid high-performance liquid chromatography (HPLC) method was used for the separation and determination of ten major phenolic compounds. Total phenolic (TPC), total flavonoid (TFC), and total phenolic acid contents (TPAC), as well as l(+)-ascorbic acid (ASA) contents, were determined. The antioxidant potential was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl radical) scavenging activity and ferric-reducing/antioxidant power (FRAP) assay, while the AChE inhibitory activity was determined by the Ellman assay for water extracts. The study revealed that excluding two herbal products containing fruits and a sample containing leaves of white mulberry, yerba mate and lemon, the remaining samples were generally consistent in terms of phenolic composition as well as antioxidant potential and AChE inhibitory activity. This reflects the health-promoting properties of the samples under study. Moreover, the results showed that the water extracts of white mulberry were richer in phenolic compounds and presented higher antioxidant activity than the hydromethanolic extracts. However, the water extracts showed low inhibitory activity against AChE. Moreover, the correlation analysis indicated a high positive relationship between phenolic composition and antioxidant activity in extracts of white mulberry. Overall, the obtained results may be useful in the evaluation of new dietary supplements and food products. The water extracts of white mulberry could be used for antioxidant purposes, while the hydromethanolic extracts could be incorporated in antioxidant formulations.
Synthesis of Novel 2-(Het)arylpyrrolidine Derivatives and Evaluation of Their Anticancer and Anti-Biofilm Activity
Authors: Smolobochkin Andrey , Gazizov Almir , Sazykina Marina , Akylbekov Nurgali , Chugunova Elena , Sazykin Ivan , Gildebrant Anastasiya , Voronina Julia , Burilov Alexander , Karchava Shorena , Klimova Maria , Voloshina Alexandra , Sapunova Anastasia , Klimanova Elena , Sashenkova Tatyana , Allayarova Ugulzhan , Balakina Anastasiya , Mishchenko Denis
Published: August 2019

A library of novel 2-(het)arylpyrrolidine-1-carboxamides were obtained via a modular approach based on the intramolecular cyclization/Mannich-type reaction of N-(4,4-diethoxybutyl)ureas. Their anti-cancer activities both in vitro and in vivo were tested. The in vitro activity of some compounds towards M-Hela tumor cell lines was twice that of the reference drug tamoxifen, whereas cytotoxicity towards normal Chang liver cell did not exceed the tamoxifen toxicity. In vivo studies showed that the number of surviving animals on day 60 of observation was up to 83% and increased life span (ILS) was up to 447%. Additionally, some pyrrolidine-1-carboxamides possessing a benzofuroxan moiety obtained were found to effectively suppress bacterial biofilm growth. Thus, these compounds are promising candidates for further development both as anti-cancer and anti-bacterial agents.
Antibacterial and Antispore Activities of Isolated Compounds from Piper cubeba L.
Authors: Alqadeeri Fatimah , Rukayadi Yaya , Abbas Faridah , Shaari Khozirah
Published: August 2019

Piper cubeba L. is the berry of a shrub that is indigenous to Java, Southern Borneo, Sumatra, and other islands in the Indian Ocean. The plant is usually used in folk traditional medicine and is an important ingredient in cooking. The purpose of this study was to isolate and purify the bioactive compounds from P. cubeba L. fractions. In addition, the isolated compounds were tested for their antibacterial and antispore activities against vegetative cells and spores of Bacillus cereus ATCC33019, B. subtilis ATCC6633, B. pumilus ATCC14884, and B. megaterium ATCC14581. The phytochemical investigation of the DCM fraction yielded two known compounds: β-asarone (1), and asaronaldehyde (2) were successfully isolated and identified from the methanol extract and its fractions of P. cubeba L. Results showed that exposing the vegetative cells of Bacillus sp. to isolated compounds resulted in an inhibition zone with a large diameter ranging between 7.21 to 9.61 mm. The range of the minimum inhibitory concentration (MIC) was between 63.0 to 125.0 µg/mL and had minimum bactericidal concentration (MBC) at 250.0 to 500.0 µg/mL against Bacillus sp. Isolated compounds at a concentration of 0.05% inactivated more than 3-Log10 (90.99%) of the spores of Bacillus sp. after an incubation period of four hours, and all the spores were killed at a concentration of 0.1%. The structures were recognizably elucidated based on 1D and 2D-NMR analyses (1H, 13C, COSY, HSQC, and HMBC) and mass spectrometry data. Compounds 1, and 2 were isolated for the first time from this plant. In conclusion, the two compounds show a promising potential of antibacterial and sporicidal activities against Bacillus sp. and thus can be developed as an anti-Bacillus agent.
Prediction of Disease-related microRNAs through Integrating Attributes of microRNA Nodes and Multiple Kinds of Connecting Edges
Authors: Xuan Ping , Li Lingling , Zhang Tiangang , Zhang Yan , Song Yingying
Published: August 2019

Identifying disease-associated microRNAs (disease miRNAs) contributes to the understanding of disease pathogenesis. Most previous computational biology studies focused on multiple kinds of connecting edges of miRNAs and diseases, including miRNA–miRNA similarities, disease–disease similarities, and miRNA–disease associations. Few methods exploited the node attribute information related to miRNA family and cluster. The previous methods do not completely consider the sparsity of node attributes. Additionally, it is challenging to deeply integrate the node attributes of miRNAs and the similarities and associations related to miRNAs and diseases. In the present study, we propose a novel method, known as MDAPred, based on nonnegative matrix factorization to predict candidate disease miRNAs. MDAPred integrates the node attributes of miRNAs and the related similarities and associations of miRNAs and diseases. Since a miRNA is typically subordinate to a family or a cluster, the node attributes of miRNAs are sparse. Similarly, the data for miRNA and disease similarities are sparse. Projecting the miRNA and disease similarities and miRNA node attributes into a common low-dimensional space contributes to estimating miRNA-disease associations. Simultaneously, the possibility that a miRNA is associated with a disease depends on the miRNA’s neighbour information. Therefore, MDAPred deeply integrates projections of multiple kinds of connecting edges, projections of miRNAs node attributes, and neighbour information of miRNAs. The cross-validation results showed that MDAPred achieved superior performance compared to other state-of-the-art methods for predicting disease-miRNA associations. MDAPred can also retrieve more actual miRNA-disease associations at the top of prediction results, which is very important for biologists. Additionally, case studies of breast, lung, and pancreatic cancers further confirmed the ability of MDAPred to discover potential miRNA–disease associations.
The Synergistic Effect of Acidic Properties and Channel Systems of Zeolites on the Synthesis of Polyoxymethylene Dimethyl Ethers from Dimethoxymethane and Trioxymethylene
Authors: Wu Jianbing , Wang Sen , Li Haitao , Zhang Yin , Shi Ruiping , Zhao Yongxiang
Published: August 2019

A series of zeolites with different topology structures, including SAPO-34, SUZ-4, ZSM-5, USY, MOR, and beta, were used to synthesize polyoxymethylene dimethyl ethers (PODEn) from dimethoxymethane (DMM) and trioxymethylene (TOM). The influence of acidic properties and channel systems were studied by activity evaluation, characterization, and theoretical calculation. The results confirmed that pore mouth diameter larger than a TOM molecule was an essential prerequisite for the synthesis of PODEn over zeolites, and the synergistic effect between medium-strong Brønsted acid sites (Brønsted MAS) and the maximal space of zeolites available determined the catalytic performance of all studied zeolites. DMM and TOM were firstly decomposed into methoxymethoxy groups (MMZ) and monomer CH2O over Brønsted MAS. Subsequently, the steric constraint of the maximum included sphere, with an appropriate size in zeolite channels, can promote the combination of CH2O and MMZ to form transition species ZO(CH2O)nCH3, which reacted with the methyl-end group to form PODEn over Brønsted MAS. Moreover, the reaction temperature showed different effects on the product selectivity and distribution, which also mainly depends on the size of the maximum space available in zeolite channels.
Highly Efficient Wideband Microwave Absorbers Based on Zero-Valent Fe@γ-Fe2O3 and Fe/Co/Ni Carbon-Protected Alloy Nanoparticles Supported on Reduced Graphene Oxide
Authors: Mederos-Henry Francisco , Mahin Julien , Pichon Benoit P. , Dîrtu Marinela M. , Garcia Yann , Delcorte Arnaud , Bailly Christian , Huynen Isabelle , Hermans Sophie
Published: August 2019

Electronic systems and telecommunication devices based on low-power microwaves, ranging from 2 to 40 GHz, have massively developed in the last decades. Their extensive use has contributed to the emergence of diverse electromagnetic interference (EMI) phenomena. Consequently, EMI shielding has become a ubiquitous necessity and, in certain countries, a legal requirement. Broadband absorption is considered the only convincing EMI shielding solution when the complete disappearance of the unwanted microwave is required. In this study, a new type of microwave absorber materials (MAMs) based on reduced graphene oxide (rGO) decorated with zero-valent Fe@γ-Fe2O3 and Fe/Co/Ni carbon-protected alloy nanoparticles (NPs) were synthesized using the Pechini sol-gel method. Synthetic parameters were varied to determine their influence on the deposited NPs size and spatial distribution. The deposited superparamagnetic nanoparticles were found to induce a ferromagnetic resonance (FMR) absorption process in all cases. Furthermore, a direct relationship between the nanocomposites’ natural FMR frequency and their composition-dependent saturation magnetization (Ms) was established. Finally, the microwave absorption efficiency (0.4 MHz to 20 GHz) of these new materials was found to range from 60% to 100%, depending on the nature of the metallic particles grafted onto rGO.
Understanding the Role of Rutile TiO2 Surface Orientation on Molecular Hydrogen Activation
Authors: Wei Baohuan , Tielens Frederik , Calatayud Monica
Published: August 2019

Titanium oxide (TiO2) has been widely used in many fields, such as photocatalysis, photovoltaics, catalysis, and sensors, where its interaction with molecular H2 with TiO2 surface plays an important role. However, the activation of hydrogen over rutile TiO2 surfaces has not been systematically studied regarding the surface termination dependence. In this work, we use density functional theory (PBE+U) to identify the pathways for two processes: the heterolytic dissociation of H2 as a hydride–proton pair, and the subsequent H transfer from Ti to near O accompanied by reduction of the Ti sites. Four stoichiometric surface orientations were considered: (001), (100), (110), and (101). The lowest activation barriers are found for hydrogen dissociation on (001) and (110), with energies of 0.56 eV and 0.50 eV, respectively. The highest activation barriers are found on (100) and (101), with energies of 1.08 eV and 0.79 eV, respectively. For hydrogen transfer from Ti to near O, the activation barriers are higher (from 1.40 to 1.86 eV). Our results indicate that the dissociation step is kinetically more favorable than the H transfer process, although the latter is thermodynamically more favorable. We discuss the implications in the stability of the hydride–proton pair, and provide structures, electronic structure, vibrational analysis, and temperature effects to characterize the reactivity of the four TiO2 orientations.
1.34 µm Q-Switched Nd:YVO4 Laser with a Reflective WS2 Saturable Absorber
Authors: Wang Taijin , Wang Yonggang , Wang Jiang , Bai Jing , Li Guangying , Lou Rui , Cheng Guanghua
Published: August 2019

In this work, a Tungsten disulfide (WS2) reflective saturable absorber (SA) fabricated using the Langmuir–Blodgett technique was used in a solid state Nd:YVO4 laser operating at 1.34 µm. A Q-switched laser was constructed. The shortest pulse width was 409 ns with the repetition rate of 159 kHz, and the maximum output power was 338 mW. To the best of our knowledge, it is the first time that short laser pulses have been generated in a solid state laser at 1.34 µm using a reflective WS2 SA fabricated by the Langmuir–Blodgett method.