bluuebunny/crossref_metadata_2025 huggingface dataset:
Interstitial Flow Recapitulates Gemcitabine Chemoresistance in A 3D Microfluidic Pancreatic Ductal Adenocarcinoma Model by Induction of Multidrug Resistance Proteins
Authors: Kramer Bart , Haan Luuk de , Vermeer Marjolein , Olivier Thomas , Hankemeier Thomas , Vulto Paul , Joore Jos , Lanz Henriëtte L.
Published: September 2019

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the most lethal cancers due to a high chemoresistance and poor vascularization, which results in an ineffective systemic therapy. PDAC is characterized by a high intratumoral pressure, which is not captured by current 2D and 3D in vitro models. Here, we demonstrated a 3D microfluidic interstitial flow model to mimic the intratumoral pressure in PDAC. We found that subjecting the S2-028 PDAC cell line to interstitial flow inhibits the proliferation, while maintaining a high viability. We observed increased gemcitabine chemoresistance, with an almost nine-fold higher EC50 as compared to a monolayer culture (31 nM versus 277 nM), and an alleviated expression and function of the multidrug resistance protein (MRP) family. In conclusion, we developed a 3D cell culture modality for studying intratissue pressure and flow that exhibits more predictive capabilities than conventional 2D cell culture and is less time-consuming, and more scalable and accessible than animal models. This increase in microphysiological relevance might support improved efficiency in the drug development pipeline.
Hydroxyapatite Formation on Self-Assembling Peptides with Differing Secondary Structures and Their Selective Adsorption for Proteins
Authors: Kojima Suzuka , Nakamura Hitomi , Lee Sungho , Nagata Fukue , Kato Katsuya
Published: September 2019

Self-assembling peptides have been employed as biotemplates for biomineralization, as the morphologies and sizes of the inorganic materials can be easily controlled. We synthesized two types of highly ordered self-assembling peptides with different secondary structures and investigated the effects of secondary structures on hydroxyapatite (HAp) biomineralization of peptide templates. All as-synthesized HAp-peptides have a selective protein adsorption capacity for basic protein (e.g., cytochrome c and lysozyme). Moreover, the selectivity was improved as peptide amounts increased. In particular, peptide–HAp templated on β-sheet peptides adsorbed more cytochrome c than peptide–HAp with α-helix structures, due to the greater than 2-times carboxyl group density at their surfaces. It can be expected that self-assembled peptide-templated HAp may be used as carriers for protein immobilization in biosensing and bioseparation applications and as enzyme-stabilizing agents.
Regulatory Effects and Interactions of the Wnt and OPG-RANKL-RANK Signaling at the Bone-Cartilage Interface in Osteoarthritis
Authors: Kovács Béla , Vajda Enikő , Nagy Előd Ernő
Published: September 2019

Cartilage and the bordering subchondral bone form a functionally active regulatory interface with a prominent role in osteoarthritis pathways. The Wnt and the OPG-RANKL-RANK signaling systems, as key mediators, interact in subchondral bone remodeling. Osteoarthritic osteoblasts polarize into two distinct phenotypes: a low secretory and an activated, pro-inflammatory and anti-resorptive subclass producing high quantities of IL-6, PGE2, and osteoprotegerin, but low levels of RANKL, thus acting as putative effectors of subchondral bone sclerosis. Wnt agonists, Wnt5a, Wisp-1 initiate excessive bone remodeling, while Wnt3a and 5a simultaneously cause loss of proteoglycans and phenotype shift in chondrocytes, with decreased expression of COL2A, aggrecan, and Sox-9. Sclerostin, a Wnt antagonist possesses a protective effect for the cartilage, while DKK-1 inhibits VEGF, suspending neoangiogenesis in the subchondral bone. Experimental conditions mimicking abnormal mechanical load, the pro-inflammatory milieu, but also a decreased OPG/RANKL ratio in the cartilage, trigger chondrocyte apoptosis and loss of the matrix via degradative matrix metalloproteinases, like MMP-13 or MMP-9. Hypoxia, an important cofactor exerts a dual role, promoting matrix synthesis via HIF-1α, a Wnt silencer, but turning on HIF-2α that enhances VEGF and MMP-13, along with aberrant collagen expression and extracellular matrix deterioration in the presence of pro-inflammatory cytokines.
Molecular Modeling Studies on the Binding Mode of the PD-1/PD-L1 Complex Inhibitors
Authors: Almahmoud Suliman , Zhong Haizhen A.
Published: September 2019

The programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) is an immune checkpoint (ICP) overexpressed in various types of tumors; thus, it has been considered as an important target for cancer therapy. To determine important residues for ligand binding, we applied molecular docking studies to PD-1/PD-L1 complex inhibitors against the PD-L1 protein. Our data revealed that the residues Tyr56, Asp122, and Lys124 play critical roles in ligand binding to the PD-L1 protein and they could be used to design ligands that are active against the PD-1/PD-L1 complex. The formation of H-bonds with Arg125 of the PD-L1 protein may enhance the potency of the PD-1/PD-L1 binding.
Impact of RNA Virus Evolution on Quasispecies Formation and Virulence
Authors: Mandary Madiiha Bibi , Masomian Malihe , Poh Chit Laa
Published: September 2019

RNA viruses are known to replicate by low fidelity polymerases and have high mutation rates whereby the resulting virus population tends to exist as a distribution of mutants. In this review, we aim to explore how genetic events such as spontaneous mutations could alter the genomic organization of RNA viruses in such a way that they impact virus replications and plaque morphology. The phenomenon of quasispecies within a viral population is also discussed to reflect virulence and its implications for RNA viruses. An understanding of how such events occur will provide further evidence about whether there are molecular determinants for plaque morphology of RNA viruses or whether different plaque phenotypes arise due to the presence of quasispecies within a population. Ultimately this review gives an insight into whether the intrinsically high error rates due to the low fidelity of RNA polymerases is responsible for the variation in plaque morphology and diversity in virulence. This can be a useful tool in characterizing mechanisms that facilitate virus adaptation and evolution.
Isolation of a Pericentromeric Satellite DNA Family in Chnootriba argus (Henosepilachna argus) with an Unusual Short Repeat Unit (TTAAAA) for Beetles
Authors: Mora Pablo , Vela Jesús , Ruiz-Mena Areli , Palomeque Teresa , Lorite Pedro
Published: September 2019

Ladybird beetles (Coccinellidae) are one of the largest groups of beetles. Among them, some species are of economic interest since they can act as a biological control for some agricultural pests whereas other species are phytophagous and can damage crops. Chnootriba argus (Coccinellidae, Epilachnini) has large heterochromatic pericentromeric blocks on all chromosomes, including both sexual chromosomes. Classical digestion of total genomic DNA using restriction endonucleases failed to find the satellite DNA located on these heterochromatic regions. Cloning of C0t-1 DNA resulted in the isolation of a repetitive DNA with a repeat unit of six base pairs, TTAAAA. The amount of TTAAAA repeat in the C. argus genome was about 20%. Fluorescence in situ hybridization (FISH) analysis and digestion of chromosomes with the endonuclease Tru9I revealed that this repetitive DNA could be considered as the putative pericentromeric satellite DNA (satDNA) in this species. The presence of this satellite DNA was tested in other species of the tribe Epilachnini and it is also present in Epilachna paenulata. In both species, the TTAAAA repeat seems to be the main satellite DNA and it is located on the pericentromeric region on all chromosomes. The size of this satDNA, which has only six base pairs is unusual in Coleoptera satellite DNAs, where satDNAs usually have repeat units of a much larger size. Southern hybridization and FISH proved that this satDNA is conserved in some Epilachnini species but not in others. This result is in concordance with the controversial phylogenetic relationships among the genera of the tribe Epilachnini, where the limits between genera are unclear.
Impact of Hierarchy on Multidisciplinary Heart-Team Recommendations in Patients with Isolated Multivessel Coronary Artery Disease
Authors: Abdulrahman Mohamed , Alsabbagh Alaa , Kuntze Thomas , Lauer Bernward , Ohlow Marc A.
Published: September 2019

Background: The Heart Team (HT) discussion has been incorporated in the current guidelines for myocardial revascularization in order to optimize treatment decisions for patients with multivessel coronary disease (MVD). There are no data in the literature, whether hierarchical issues do have an impact on HT decisions. We aimed to analyze the therapeutic recommendations of the multidisciplinary “Heart Team” (HT) for coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) if: (a) The head of cardiovascular surgery (HOS) and the head of cardiology (HOC) were present during the HT meeting, (b) both directors were absent, (c) only HOS or HOC was present. Methods: Retrospective analysis of all HT discussions between 2012 and 2015 in patients with isolated MVD (without any other cardiac problems requiring surgery). Results: During the study period, we analyzed 209 HT discussions in patients with isolated MVD. If neither HOS nor HOC was present at the HT discussion, the therapeutic recommendation was in 69% CABG and 31% PCI. If HOS and HOC were present in 77% CABG and 23% PCI was recommended (p = 0.34). If only HOS was present therapeutic recommendation was in 83% CABG and 17% PCI, and if only HOC was present the recommendation was in 54% CABG and 46% PCI (p < 0.0001). This difference did not attenuate during the study period. Conclusions: The hierarchy of the participating physicians significantly impacts treatment recommendations of a multidisciplinary HT in patients with isolated MVD. This impact did not attenuate after several years of Heart Team interaction.
NK Cell Plasticity in Cancer
Authors: Liu Sizhe , Dhar Payal , Wu Jennifer D.
Published: September 2019

Natural killer (NK) cells are critical immune components in controlling tumor growth and dissemination. Given their innate capacity to eliminate tumor cells without prior sensitization, NK-based therapies for cancer are actively pursued pre-clinically and clinically. However, recent data suggest that tumors could induce functional alterations in NK cells, polarizing them to tumor-promoting phenotypes. The potential functional plasticity of NK cells in the context of tumors could lead to undesirable outcomes of NK-cell based therapies. In this review, we will summarize to-date evidence of tumor-associated NK cell plasticity and provide our insights for future investigations and therapy development.
Metoclopramide and Levosulpiride Use and Subsequent Levodopa Prescription in the Korean Elderly: The Prescribing Cascade
Authors: Huh Youn , Kim Do-Hoon , Choi Moonyoung , Park Joo-Hyun , Kwon Do-Young , Jung Jin-Hyung , Han Kyungdo , Park Yong-Gyu
Published: September 2019

The aim of this study was to investigate the prescribing cascade phenomenon of dopaminergic drugs such as levodopa in the management of gastroprokinetic drugs induced parkinsonism. Based on the Korea National Health Insurance Service (NHIS)-Senior Cohort Database, we analyzed patients aged ≥65 years, between 2009 and 2013, who obtained new prescriptions for levodopa through the NHIS during this period. Those who were prescribed levodopa from 2002 to 2008 were excluded, only patients who were prescribed metoclopramide and levosulpiride within 90 days of receiving the levodopa prescription were included. Those who did not receive levodopa were used as a control group for 1:3 age and sex matching. We assessed 1824 and 1197 levodopa cases for metoclopramide and levosulpiride use, respectively. The matched controls for each levodopa case were 5472 and 3591, respectively. We used conditional logistic regression to determine the odds ratio (OR) for initiation of levodopa therapy in patients using metoclopramide and levosulpiride, relative to nonusers, after adjusting for age, sex, and exposure to antipsychotic medication. Both metoclopramide (OR = 3.04; 95% confidence interval, CI, 2.46–3.77) and levosulpiride (OR = 3.32; 95% CI, 2.56–4.3) users were three times more likely to begin using medication containing levodopa, compared to nonusers. Metoclopramide and levosulpiride were frequently prescribed within 90 days of receiving a prescription for levodopa. Before prescribing levodopa, it should be considered whether the adverse event is actually a side effect caused by metoclopramide and levosulpiride.
Efficiency of the Inclusion of Rebamipide in the Eradication Therapy for Helicobacter pylori Infection: Meta-Analysis of Randomized Controlled Studies
Authors: Andreev Dmitrii N. , Maev Igor V. , Dicheva Diana T.
Published: September 2019

Background: There has been a negative trend in the effectiveness of classic eradication therapy regimens for Helicobacter pylori (H. pylori), which has largely been determined from the emergence and spread of antibiotic resistance. Several studies have shown that adding rebamipide to eradication regimens leads to an increase in the effectiveness of treatment. Aim: To evaluate the efficacy and safety of including rebamipide in the eradication regimens for H. pylori infection. Methods: The literature search was conducted in the MEDLINE/PubMed, EMBASE, Cochrane Central Register, Korean Medical Citation Index, and Russian Science Citation Index databases. All identified randomized controlled trials comparing rebamipide supplementation with non-rebamipide-containing eradication regimens for the treatment of H. pylori infection were included in the final analysis. Results: We identified 11 randomized controlled trials (RCTs) involving 1227 patients (631 in groups with rebamipide and 596 in groups without rebamipide). The meta-analysis showed that the addition of rebamipide to eradication regimens significantly increased the effectiveness of treatment (odds ratio (OR) 1.753, 95% confidence interval (CI) 1.312–2.333, p < 0.001). The subgroup analysis demonstrated that rebamipide significantly increased the effectiveness of eradication when added to a dual therapy regimen (OR 1.766, 95% CI: 1.167–2.495, p = 0.006); however, no significant improvement in effectiveness was observed when it was added to the triple therapy regimen (OR 1.638, 95% CI 0.833–3.219, p = 0.152). Conclusion: This meta-analysis demonstrated that the addition of rebamipide to H. pylori eradication regimens significantly increases the effectiveness of treatment.
Subtyping Lung Cancer Using DNA Methylation in Liquid Biopsies
Authors: Nunes Sandra P. , Diniz Francisca , Moreira-Barbosa Catarina , Constâncio Vera , Silva Ana Victor , Oliveira Júlio , Soares Marta , Paulino Sofia , Cunha Ana Luísa , Rodrigues Jéssica , Antunes Luís , Henrique Rui , Jerónimo Carmen
Published: September 2019

Background: Lung cancer (LCa) is the most frequently diagnosed and lethal cancer worldwide. Histopathological subtyping, which has important therapeutic and prognostic implications, requires material collection through invasive procedures, which might be insufficient to enable definitive diagnosis. Aberrant DNA methylation is an early event in carcinogenesis, detectable in circulating cell-free DNA (ccfDNA). Herein, we aimed to assess methylation of selected genes in ccfDNA from LCa patients and determine its accuracy for tumor subtyping. Methods: Methylation levels of APC, HOXA9, RARβ2, and RASSF1A were assessed in three independent study groups (study group #1: 152 tissue samples; study group #2: 129 plasma samples; study group #3: 28 benign lesions of lung) using quantitative methylation-specific PCR. Associations between gene promoter methylation levels and LCa subtypes were evaluated using non-parametric tests. Receiver operating characteristic (ROC) curve analysis was performed. Results: In study group #2, HOXA9 and RASSF1A displayed higher methylation levels in small-cell lung cancer (SCLC) than in non-small-cell lung cancer (NSCLC). HOXA9 displayed high sensitivity (63.8%), whereas RASSF1A disclosed high specificity (96.2%) for SCLC detection in ccfDNA. Furthermore, HOXA9 methylation levels showed to be higher in squamous cell carcinoma in comparison with adenocarcinoma in study group #1. Conclusions: Methylation level assessments in ccfDNA may provide a minimally invasive procedure for LCa subtyping, complementing standard diagnostic procedures.
Current Characteristics Estimation of Si PV Modules Based on Artificial Neural Network Modeling
Authors: Xu Xiaobo , Zhang Xiaocheng , Huang Zhaowu , Xie Shaoyou , Gu Wenping , Wang Xiaoyan , Zhang Lin , Zhang Zan
Published: September 2019

In the photovoltaic (PV) field, the outdoor evaluation of a PV system is quite complex, due to the variations of temperature and irradiance. In fact, the diagnosis of the PV modules is extremely required in order to maintain the optimum performance. In this paper, an artificial neural network (ANN) is proposed to build and train the model, and evaluate the PV module performance by mean bias error, mean square error and the regression analysis. We take temperature, irradiance and a specific voltage for input, and a specific current value for output, repeat several times in order to obtain an I-V curve. The main feature lies to the data-driven black-box method, with the ignorance of any analytical equations and hence the conventional five parameters (serial resistance, shunt resistance, non-ideal factor, reverse saturation current, and photon current). The ANN is able to predict the I-V curves of the Si PV module at arbitrary irradiance and temperature. Finally, the proposed algorithm has proved to be valid in terms of comparison with the testing dataset.
Corrosion Behavior of SMA490BW Steel and Welded Joints for High-Speed Trains in Atmospheric Environments
Authors: Wu Xiangyang , Zhang Zhiyi , Qi Weichuang , Tian Renyong , Huang Shiming , Shi Chunyuan
Published: September 2019

Currently, high-speed trains work under various atmospheric environments, and the bogie as a key component suffers serious corrosion. To investigate the corrosion behavior of bogies in industrial atmospheric environments, the periodic immersion wet/dry cyclic corrosion test for SMA490BW steel and automatic metal active gas (MAG) welded joints used for bogies was conducted in the present work. Corrosion weight loss rate, structure, and composition of rust layers as well as electrochemistry parameters were investigated. The results showed that the corrosion weight loss rate decreased with increasing corrosion time; furthermore, the corrosion weight loss rate of the welded joints was lower than that of SMA490BW steel. The XRD results showed that the rust layers formed on SMA490BW steel and its welded joints were mainly composed of α-FeOOH, γ-FeOOH, Fe2O3, and Fe3O4. The observation of surface morphology indicated that the rust layers of the welded joints were much denser and had a much finer microstructure compared with those of SMA490BW steel. After corrosion for 150 h, the corrosion potential of the welded joints with rust layers was higher than that of SMA490BW steel. In short, the welded joints exhibited better corrosion resistance than SMA490BW steel because of the higher content of alloy elements, as shown in this work.
Homogenization and Localization of Ratcheting Behavior of Composite Materials and Structures with the Thermal Residual Stress Effect
Authors: Yang Danhui , Yang Zhibo , Zhai Zhi , Chen Xuefeng
Published: September 2019

In this contribution, the ratcheting behavior and local field distribution of unidirectional metal matrix composites are investigated under cyclic loading. To that end, we extended the finite-volume direct averaging micromechanics (FVDAM) theory by incorporating the rule of nonlinear kinematic hardening. The proposed method enables efficient and accurate simulation of the ratcheting behavior of unidirectional composites. The local satisfaction of equilibrium equations of the FVDAM theory facilitates quick and rapid convergence during the plastic iterations. To verify the proposed theory, a finite-element (FE) based unit cell model is constructed with the same mesh discretization. The remarkable correlation of the transverse response and local field distribution generated by the FVDAM and FE techniques demonstrates the effectiveness and accuracy of the proposed models. The stress discontinuities along the fiber/matrix interface that are generic to the finite-element theory are absent in the FVDAM prediction. The effects of thermal residual stresses induced during the consolidation process, as well as fiber orientations, are revealed. The generated results indicate that the FVDAM is well suited for simulating the elastic-plastic ratcheting behavior of metal matrix composites, which will provide the conventional finite-element based technique with an attractive alternative.
Lung Cryobiopsy for the Diagnosis of Interstitial Lung Diseases: A Series Contribution to a Debated Procedure
Authors: Harari Sergio , Cereda Francesca , Pane Federico , Cavazza Alberto , Papanikolaou Nikolaos , Pelosi Giuseppe , Scarioni Monica , Uslenghi Elisabetta , Zompatori Maurizio , Caminati Antonella
Published: September 2019

Introduction: Transbronchial cryobiopsy is an alternative to surgical biopsy for the diagnosis of fibrosing interstitial lung diseases, although the role of this relatively new method is rather controversial. Aim of this study is to evaluate the diagnostic performance and the safety of transbronchial cryobiopsy in patients with fibrosing interstitial lung disease. Materials and methods: The population in this study included patients with interstitial lung diseases who underwent cryobiopsy from May 2015 to May 2018 at the Division of Pneumology of San Giuseppe Hospital in Milan and who were retrospectively studied. All cryobiopsy procedures were performed under fluoroscopic guidance using a flexible video bronchoscope and an endobronchial blocking system in the operating room with patients under general anaesthesia. The diagnostic performance and safety of the procedure were assessed. The main complications evaluated were endobronchial bleeding and pneumothorax. All cases were studied with a multidisciplinary approach, before and after cryobiopsy. Results: Seventy-three patients were admitted to this study. A specific diagnosis was reached in 64 cases, with a diagnostic sensitivity of 88%; 5 cases (7%) were considered inadequate, 4 cases (5%) were found to be non-diagnostic. Only one major bleeding event occurred (1.4%), while 14 patients (19%) experienced mild/moderate bleeding events while undergoing bronchoscopy; 8 cases of pneumothorax (10.9%) were reported, of which 2 (2.7%) required surgical drainage. Conclusions: When performed under safe conditions and in an experienced center, cryobiopsy is a procedure with limited complications having a high diagnostic yield in fibrotic interstitial lung disease.
Spectral Characterization of Copper and Iron Sulfide Combustion: A Multivariate Data Analysis Approach for Mineral Identification on the Blend
Authors: Díaz Walter , Toro Carlos , Balladares Eduardo , Parra Victor , Coelho Pablo , Reyes Gonzalo , Parra Roberto
Published: September 2019

The pyrometallurgical processes for primary copper production have only off-line and time-demanding analytical techniques to characterize the in and out streams of the smelting and converting steps. Since these processes are highly exothermic, relevant process information could potentially be obtained from the visible and near-infrared radiation emitted to the environment. In this work, we apply spectral sensing and multivariate data analysis methodologies to identify and classify copper and iron sulfide minerals present in the blend from spectra measured during their combustion in a laboratory drop-tube setup, in which chemical reactions that take place in flash smelting furnaces can be reproduced. Controlled combustion experiments were conducted with two industrial concentrates and with high-grade mineral species as well, with a focus on pyrite and chalcopyrite. Exploratory analysis by means of Principal Component Analysis (PCA) applied on the spectral data depicted high correlation features among species with similar elemental compositions. Classification algorithms were tested on the spectral data, and a classification accuracy of 95.3% with a support vector machine (SVM) algorithm with a Gaussian kernel was achieved. The results obtained by the described procedures are shown to be very promising as a first step in the development of a predictive and analytical tool in search of fitting the current need for real-time control of pyrometallurgical processes.
The Role of Microstructure on the Tensile Plastic Behaviour of Ductile Iron GJS 400 Produced through Different Cooling Rates—Part II: Tensile Modelling
Authors: Angella Giuliano , Donnini Riccardo , Ripamonti Dario , Górny Marcin , Zanardi Franco
Published: September 2019

Tensile testing on ductile iron GJS 400 with different microstructures produced through four different cooling rates was performed in order to investigate the relevance of the microstructure’s parameters on its plastic behaviour. Tensile flow curve modelling was carried out with the Follansbee and Estrin-Kocks-Mecking approach that allowed for an explicit correlation between plastic behaviour and some microstructure parameters. In the model, the ferritic grain size and volume fraction of pearlite and ferrite gathered in the first part of this investigation were used as inputs, while other parameters, like nodule count and interlamellar spacing in pearlite, were neglected. The model matched very well with the experimental flow curves at high strains, while some mismatch was found only at small strains, which was ascribed to the decohesion between the graphite nodules and the ferritic matrix that occurred just after yielding. It can be concluded that the plastic behaviour of GJS 400 depends mainly on the ferritic grain size and pearlitic volume fraction, and other microstructure parameters can be neglected, primarily because of their high nodularity and few defects.
Light-Weight Topological Optimization for Upper Arm of an Industrial Welding Robot
Authors: Yao Ping , Zhou Kang , Lin Yuan , Tang Yong
Published: September 2019

To reduce weight and improve overall performance of the industrial welding robot, light-weight design using the finite element method and structural topological optimization is presented in this paper. The work analyzed an upper arm of an industrial welding robot in the most unfavorable working condition, both under static and dynamic working situations, using ABAQUS and ADAMS software tools. Then the Tosca unit in ABAQUS was employed to accomplish the structural topological optimization, in order to reduce weight and improve the natural frequencies under the situation of low orders. The analyses results showed that the actual weight had been reduced to 17.9%, and the natural frequencies in low orders had increased. The maximum Mises stress, tensile stress, and elastic displacement of the gyration center had decreased. Lastly, an actual product was produced according to the model obtained from preceding analyses. The experiments of the repeatability tests showed that the overall performance of the optimized upper arm had been improved when compared to the original one. This research can present references and foundations for the kinetic analyses under the static and dynamic working conditions, and structural topological optimization designs for relative industrial welding robots.
Efficient and Precise Grinding of Sapphire Glass Based on Dry Electrical Discharge Dressed Coarse Diamond Grinding Wheel
Authors: Lu Yanjun , Luo Wang , Wu Xiaoyu , Zhou Chaolan , Xu Bin , Zhao Hang , Li Liejun
Published: September 2019

In this paper, in view of low grinding efficiency and poor ground surface quality of sapphire glass, the coarse diamond grinding wheel dressed by dry impulse electrical discharge was proposed to perform efficient and precise grinding machining of sapphire glass. The dry electrical discharge dressing technology was employed to obtain high grain protrusion and sharp micro-grain cutting edges. The influences of grinding process parameters such as wheel speed, depth of cut and feed speed on the ground surface quality, grinding force and grinding force ratio on sapphire glass were investigated, and the relationship between grinding force and ground surface quality was also revealed. The experimental results show that the grain protrusion height on the surface of a coarse diamond grinding wheel dressed by dry electrical discharge can reach 168.5 µm. The minimum line roughness Ra and surface roughness Sa of ground sapphire glass surface were 0.194 µm and 0.736 µm, respectively. In order to achieve highly efficient ground quality of sapphire glass, the depth of cut was controlled within 7 µm, and the wheel speed and feed speed were 3000–5000 r/min and 10–20 mm/min, respectively. The influences of feed speed and wheel speed on grinding force ratio were more significant, but the influence of depth of cut was little.
A Monte Carlo Method for Determining the Response Relationship between Two Commonly Used Detectors to Indirectly Measure Alpha Particle Radiation Activity
Authors: Tichacek Christopher J. , Budzevich Mikalai M. , Wadas Thaddeus J. , Morse David L. , Moros Eduardo G.
Published: September 2019

Using targeted ligands to deliver alpha-emitting radionuclides directly to tumor cells has become a promising therapeutic strategy. To calculate the radiation dose to patients, activities of parent and daughter radionuclides must be measured. Scintillation detectors can be used to quantify these activities; however, activities found in pre-clinical and clinical studies can exceed their optimal performance range. Therefore, a method of correcting scintillation detector measurements at higher activities was developed using Monte Carlo modeling. Because there are currently no National Institute of Standards and Technology traceable Actinium-225 (225Ac) standards available, a well-type ionization chamber was used to measure 70.3 ± 7.0, 144.3 ± 14.4, 222.0 ± 22.2, 299.7 ± 30.0, 370.0 ± 37.0, and 447.7 ± 44.7 kBq samples of 225Ac obtained from Oak Ridge National Lab. Samples were then placed in a well-type NaI(Tl) scintillation detector and spectra were obtained. Alpha particle activity for each species was calculated using gamma abundance per alpha decay. MCNP6 Monte Carlo software was used to simulate the 4π-geometry of the NaI(Tl) detector. Using the ionization chamber reading as activity input to the Monte Carlo model, spectra were obtained and compared to NaI(Tl) spectra. Successive simulations of different activities were run until a spectrum minimizing the mean percent difference between the two was identified. This was repeated for each sample activity. Ionization chamber calibration measurements showed increase in error from 3% to 10% as activities decreased, resulting from decreasing detection efficiency. Measurements of 225Ac using both detector types agreed within 7% of Oak Ridge stated activities. Simulated Monte Carlo spectra of 225Ac were successfully generated. Activities obtained from these spectra differed with ionization chamber readings up to 156% at 147.7 kBq. Simulated spectra were then adjusted to correct NaI(Tl) measurements to be within 1%. These were compared to ionization chamber readings and a response relationship was determined between the two instruments. Measurements of 225Ac and daughter activity were conducted using a NaI(Tl) scintillation detector calibrated for energy and efficiency and an ionization chamber calibrated for efficiency using a surrogate calibration reference. Corrections provided by Monte Carlo modeling improve the accuracy of activity quantification for alpha-particle emitting radiopharmaceuticals in pre-clinical and clinical studies.
Petroleum Hydrocarbon Contamination in Terrestrial Ecosystems—Fate and Microbial Responses
Authors: Truskewycz Adam , Gundry Taylor D. , Khudur Leadin S. , Kolobaric Adam , Taha Mohamed , Aburto-Medina Arturo , Ball Andrew S. , Shahsavari Esmaeil
Published: September 2019

Petroleum hydrocarbons represent the most frequent environmental contaminant. The introduction of petroleum hydrocarbons into a pristine environment immediately changes the nature of that environment, resulting in reduced ecosystem functionality. Natural attenuation represents the single, most important biological process which removes petroleum hydrocarbons from the environment. It is a process where microorganisms present at the site degrade the organic contaminants without the input of external bioremediation enhancers (i.e., electron donors, electron acceptors, other microorganisms or nutrients). So successful is this natural attenuation process that in environmental biotechnology, bioremediation has developed steadily over the past 50 years based on this natural biodegradation process. Bioremediation is recognized as the most environmentally friendly remediation approach for the removal of petroleum hydrocarbons from an environment as it does not require intensive chemical, mechanical, and costly interventions. However, it is under-utilized as a commercial remediation strategy due to incomplete hydrocarbon catabolism and lengthy remediation times when compared with rival technologies. This review aims to describe the fate of petroleum hydrocarbons in the environment and discuss their interactions with abiotic and biotic components of the environment under both aerobic and anaerobic conditions. Furthermore, the mechanisms for dealing with petroleum hydrocarbon contamination in the environment will be examined. When petroleum hydrocarbons contaminate land, they start to interact with its surrounding, including physical (dispersion), physiochemical (evaporation, dissolution, sorption), chemical (photo-oxidation, auto-oxidation), and biological (plant and microbial catabolism of hydrocarbons) interactions. As microorganism (including bacteria and fungi) play an important role in the degradation of petroleum hydrocarbons, investigations into the microbial communities within contaminated soils is essential for any bioremediation project. This review highlights the fate of petroleum hydrocarbons in tertial environments, as well as the contributions of different microbial consortia for optimum petroleum hydrocarbon bioremediation potential. The impact of high-throughput metagenomic sequencing in determining the underlying degradation mechanisms is also discussed. This knowledge will aid the development of more efficient, cost-effective commercial bioremediation technologies.
Castanea sativa Mill. Shells Aqueous Extract Exhibits Anticancer Properties Inducing Cytotoxic and Pro-Apoptotic Effects
Authors: Cacciola Nunzio Antonio , Squillaci Giuseppe , D’Apolito Mariella , Petillo Orsolina , Veraldi Francesco , La Cara Francesco , Peluso Gianfranco , Margarucci Sabrina , Morana Alessandra
Published: September 2019

In this study, chestnut shells (CS) were used in order to obtain bioactive compounds through different extraction procedures. The aqueous extracts were chemically characterized. The highest extraction yield and total phenolic content was obtained by conventional liquid extraction (CLE). Gallic and protocatechuic acids were the main simple phenols in the extract, with 86.97 and 11.20 mg/g chestnut shells dry extract (CSDE), respectively. Six tumor cell lines (DU 145, PC-3, LNCaP, MDA-MB-231, MCF-7, and HepG2) and one normal prostate epithelial cell line (PNT2) were exposed to increasing concentration of CSDE (1–100 µg/mL) for 24 h, and cell viability was evaluated using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide MTT assay. A reduced rate in cell viability was observed in DU 145, PC-3, LNCaP, and MCF-7 cells, while viability of the other assessed cells was not affected, except for PNT2 cells at a concentration of 100 μg/mL. Furthermore, CSDE—at concentrations of 55.5 and 100 µg/mL—lead to a significant increase of apoptotic cells in DU 145 cells of 28.2% and 61%, respectively. In conclusion, these outcomes suggested that CS might be used for the extraction of several polyphenols that may represent good candidates for alternative therapies or in combination with current chemotherapeutics.
Fractionated Antioxidant and Anti-inflammatory Kernel Oil from Torreya fargesii
Authors: Zhou Xianrong , Shang Jin , Qin Mingyi , Wang Jianhua , Jiang Bo , Yang Hui , Zhang Yan
Published: September 2019

Polymethylene-interrupted polyunsaturated fatty acids (PMI-PUFAs) are emerging functional lipids with proven antioxidant and anti-inflammatory effects. In this study, a typical PMI-PUFA, sciadonic acid (C20:3, 5c 11c 14c), was enriched in the kernel oil of Torreya fargesii (T. fargesii) by fractionation. Fractionated kernel oil of T. fargesii (containing 25% sciadonic acid) showed equal stability and similar radical scavenging ability compared with the non-fractionated oil. In anti-inflammatory tests, fractionated kernel oil was shown to inhibit the activity of phosphodiesterase (PDE-5, efficiency 80% at 133.7 μg/mL) and lipoxygenase-5 (LOX-5, efficiency 65% at 66.7 μg/mL) more effectively than the non-fractionated oil. This shows that increasing the amount of sciadonic acid can enhance the anti-inflammatory effect of the kernel oil. This research also indicates that fractionation is a feasible way to obtain sciadonic acid–rich functional oil with potential pharmacological effects.
Deepening Inside the Pictorial Layers of Etruscan Sarcophagus of Hasti Afunei: An Innovative Micro-Sampling Technique for Raman/SERS Analyses
Authors: Gagliano Candela Rossella , Lombardi Livia , Ciccola Alessandro , Serafini Ilaria , Bianco Armandodoriano , Postorino Paolo , Pellegrino Lorella , Bruno Maurizio
Published: September 2019

The Hasti Afunei sarcophagus is a large Etruscan urn, made up of two chalky alabaster monoliths. Dated from the last quarter of the third century BC, it was found in 1826 in the small town of Chiusi (Tuscany- Il Colle place) by a landowner, Pietro Bonci Casuccini, who made it part of his private collection. The noble owner’s collection was sold in 1865 to the Royal Museum of Palermo (today under the name of Antonino Salinas Regional Archaeological Museum), where it is still displayed. The sarcophagus is characterized by a complex iconography that is meticulously illustrated through an excellent sculptural technique, despite having subjected to anthropic degradation and numerous restorative actions during the last century. During the restoration campaign carried out between 2016 and 2017, a targeted diagnostic campaign was carried out to identify the constituent materials of the artefact, the pigments employed and the executive technique, in order to get an overall picture of conservation status and conservative criticalities. In particular, this last intervention has allowed the use of the innovative micro-sampling technique, patented by the Cultural Heritage research group of Sapienza, in order to identify the employee of lake pigments through SERS analyses. Together with this analysis, Raman and NMR technique have completed the information requested by restorers, for what concerns the wax employed as protective layers, and allowed to rebuild the conservation history of the sarcophagus. In fact, together with the identification of red ocher and yellow ocher, carbon black, Egyptian blue and madder lake, pigments compatible with the historical period of the work, modern pigments (probably green Paris, chrome orange, barium yellow, blue phtalocyanine) have been recognized, attributable with not documented intervention during the eighteenth and twentieth centuries.
Targeted Delivery of Plasminogen Activators for Thrombolytic Therapy: An Integrative Evaluation
Authors: Ma Yunn-Hwa , Liu Chih-Hsin , Liang Yueh , Chen Jyh-Ping , Wu Tony
Published: September 2019

In thrombolytic therapy, plasminogen activators (PAs) are still the only group of drug approved to induce thrombolysis, and therefore, critical for treatment of arterial thromboembolism, such as stroke, in the acute phase. Functionalized nanocomposites have attracted great attention in achieving target thrombolysis due to favorable characteristics associated with the size, surface properties and targeting effects. Many PA-conjugated nanocomposites have been prepared and characterized, and some of them has been demonstrated with therapeutic efficacy in animal models. To facilitate future translation, this paper reviews recent progress of this area, especially focus on how to achieve reproducible thrombolysis efficacy in vivo.
Water Extraction Kinetics of Bioactive Compounds of Fucus vesiculosus
Authors: Ferreira Ricardo M. , Ramalho Ribeiro Ana , Patinha Carla , Silva Artur M. S. , Cardoso Susana M. , Costa Rui
Published: September 2019

Brown macroalgae, particularly those from Fucus genus, are a rich and balanced source of bioactive nutrients and phytochemicals, such as dietary fibres (fucoidans, laminarins, and/or alginates), phlorotannins, and fucoxanthin, and some minerals, such as iodine, which have been demonstrated to possess numerous health-promoting properties. In fact, aqueous extracts of Fucus vesiculosus have been used as food supplements due to its rich content in bioactive compounds, though no study has been published on the optimization of this operation. Therefore, this study aimed to evaluate the impact of different extraction temperatures (25 °C, 50 °C, 75 °C, 100 °C, and 120 °C) and times (5 min, 1 h, 2 h, and 4 h) on the recovery of those bioactive compounds. The temperature was observed to positively influence the extraction of crude mass and of fucose polysaccharides only at 75 °C and above, and of iodine extraction at 50 °C and above. At these temperatures, time also showed to increase yields. Yields of crude extract, fucose, and iodine were successfully mathematically modelled with a power law, and its maximum yields were obtained at the highest temperature studied (120 °C) and longest extraction time (4 h). Iodine yield at these conditions provided extracts with relevant content to contribute to the recommended daily ingestion. Phlorotannins were significantly recovered at 120 °C though evidence of degradation was observed during time.
Selectively Charged and Zwitterionic Analogues of the Smallest Immunogenic Structure of Streptococcus Pneumoniae Type 14
Authors: Gragnani Tiziana , Cuffaro Doretta , Fallarini Silvia , Lombardi Grazia , D’Andrea Felicia , Guazzelli Lorenzo
Published: September 2019

Zwitterionic polysaccharides (ZPs) have been shown in recent years to display peculiar immunological properties, thus attracting the interest of the carbohydrate research community. To fully elucidate the mechanisms underlying these properties and exploit the potential of this kind of structures, in depth studies are still required. In this context, the preparation of two cationic, an anionic, as well as two zwitterionic tetrasaccharide analogues of the smallest immunogenic structure of Streptococcus pneumoniae type 14 (SP14) capsular polysaccharide are presented. By exploiting a block strategy, the negative charge has been installed on the non-reducing end of the lactose unit of the tetrasaccharide and the positive charge either on the non-reducing end of the lactosamine moiety or on an external linker. These structures have then been tested by competitive ELISA, showing that the structural variations we made do not modify the affinity of the neutral compound to binding to a specific antibody. However, lower efficacies than the natural SP14 compound were observed. The results obtained, although promising, point to the need to further elongate the polysaccharide structure, which is likely too short to cover the entire epitopes.
Effect of Graphene Oxide Nano-Sheets on Structural, Morphological and Photocatalytic Activity of BiFeO3-Based Nanostructures
Authors: Irfan Syed , Liang Guang-xing , Li Fu , Chen Yue-xing , Rizwan Syed , Jin Jingcheng , Zhuanghao Zheng , Ping Fan
Published: September 2019

Photocatalysts are widely used for the elimination of organic contaminants from waste-water and H2 evaluation by water-splitting. Herein, the nanohybrids of lanthanum (La) and selenium (Se) co-doped bismuth ferrites with graphene oxide were synthesized. A structural analysis from X-ray diffraction confirmed the transition of phases from rhombohedral to the distorted orthorhombic. Scanning electron microscopy (SEM) revealed that the graphene nano-sheets homogenously covered La–Se co-doped bismuth ferrites nanoparticles, particularly the (Bi0.92La0.08Fe0.50Se0.50O3–graphene oxide) LBFSe50-G sample. Moreover, the band-gap nanohybrids of La–Se co-doped bismuth ferrites were estimated from diffuse reflectance spectra (DRS), which showed a variation from 1.84 to 2.09 eV, because the lowering of the band-gap can enhance photocatalytic degradation efficiency. Additionally, the photo-degradation efficiencies increased after the incorporation of graphene nano-sheets onto the La–Se co-doped bismuth ferrite. The maximum degradation efficiency of the LBFSe50-G sample was up to 80%, which may have been due to reduced band-gap and availability of enhanced surface area for incoming photons at the surface of the photocatalyst. Furthermore, photoluminescence spectra confirmed that the graphene oxide provided more electron-capturing sites, which decreased the recombination time of the photo-generated charge carriers. Thus, we can propose that the use of nanohybrids of La–Se co-doped bismuth ferrite with graphene oxide nano-sheets is a promising approach for both water-treatment and water-splitting, with better efficiencies of BiFeO3.
A Facile Method of Preparing the Asymmetric Supercapacitor with Two Electrodes Assembled on a Sheet of Filter Paper
Authors: Jiao Shasha , Li Tiehu , Xiong Chuanyin , Tang Chen , Dang Alei , Li Hao , Zhao Tingkai
Published: September 2019

An asymmetric supercapacitor was prepared on a sheet of filter paper with two modified surfaces acting as electrodes in 1 M potassium hydroxide aqueous solution. By choosing carbon nanotubes and two different kinds of metal oxides (zinc oxide and ferro ferric oxide) as electrode materials, the asymmetric supercapacitor was successfully fabricated. The results showed that this device exhibited a wide potential window of 1.8 V and significantly improved electrochemical performances of its counterparts. Particularly, the one-sheet asymmetric supercapacitor demonstrated high energy density of 116.11 W h/kg and power density 27.48 kW/kg, which was attributed to the combined action and shortened distance between the two electrodes, respectively. Besides, it showed superior electrochemical cycling stability with 87.1% capacitance retention under room temperature. These outstanding results can not only give researchers new insights into compact energy storage systems, but they also provide a good prospect for flexible asymmetric supercapacitors.