bluuebunny/crossref_metadata_2025 huggingface dataset:
An In Situ Incorporation of Acrylic Acid and ZnO Nanoparticles into Polyamide Thin Film Composite Membranes for Their Effect on Membrane pH Responsive Behavior
Authors: Malatjie Kgolofelo I. , Mbuli Bhekani S. , Moutloali Richard M. , Ngila Catherine J.
Published: November 2021

This paper focuses on an in situ interfacial polymerization modification of polyamide thin film composite membranes with acrylic acid (AA) and zinc oxide (ZnO) nanoparticles. Consequent to this modification, the modified polyamide thin film composite (PA–TFC) membranes exhibited enhanced water permeability and Pb (II) heavy metal rejection. For example, the 0.50:1.50% ZnO/AA modified membranes showed water permeability of 29.85 ± 0.06 L·m−2·h−1·kPa−1 (pH 3), 4.16 ± 0.39 L·m−2·h−1·kPa−1 (pH 7), and 2.80 ± 0.21 L·m−2·h−1·kPa−1 1 (pH 11). This demonstrated enhanced pH responsive properties, and improved water permeability properties against unmodified membranes (2.29 ± 0.59 L·m−2·h−1·kPa−1, 1.79 ± 0.27 L·m−2·h−1·kPa−1, and 0.90 ± 0.21 L·m−2·h−1·kPa−1, respectively). Furthermore, the rejection of Pb (II) ions by the modified PA–TFC membranes was found to be 16.11 ± 0.12% (pH 3), 30.58 ± 0.33% (pH 7), and 96.67 ± 0.09% (pH 11). Additionally, the membranes modified with AA and ZnO/AA demonstrated a significant pH responsiveness compared to membranes modified with only ZnO nanoparticles and unmodified membranes. As such, this demonstrated the swelling behavior due to the inherent “gate effect” of the modified membranes. This was illustrated by the rejection and water permeation behavior, hydrophilic properties, and ion exchange capacity of the modified membranes. The pH responsiveness for the modified membranes was due to the –COOH and –OH functional groups introduced by the AA hydrogel and ZnO nanoparticles.
Mixed Matrix Membranes Containing a Biphenyl-Based Knitting Aryl Polymer and Gas Separation Performance
Authors: Martinez-Tirado Raquel , Yuriychuk Nastasia , Iglesias Marta , López-González Mar , Maya Eva M.
Published: November 2021

Novel mixed matrix membranes (MMMs) were prepared using Matrimid (M), polysulfone (PSF) or polyphenylene oxide (PPO) as the continuous phase and a porous biphenyl-based knitting aryl polymer as a filler, synthesized through the Friedel–Craft reaction. The filler had little influence on the thermal and morphological properties of the membranes but affected the mechanical and gas transport properties, which were different depending on the type of matrix. Thus, in the case of MMMs based on Matrimid, the filler increased considerably the permeability to all gases, although no improvements in selectivity were achieved. A PSF-based MMM showed minor permeability increases, but not in all gases, while the selectivity was particularly improved for hydrogen separations. A PPO-based MMM did not exhibit variation in permeability nor in permselectivity with the addition of the filler.
The Effect of Flow-Induced Vibration on Heat and Mass Transfer Performance of Hollow Fiber Membranes in the Humidification/Dehumidification Process
Authors: Li Zhenxing , Chen Bo , Liang Caihang , Li Nanfeng , Zhao Yunyun , Dong Chuanshuai
Published: November 2021

Cross-flow hollow fiber membranes are commonly applied in humidification/dehumidification. Hollow fiber membranes vibrate and deform under the impinging force of incoming air and the gravity of liquid in the inner tube. In this study, fiber deformation was caused by the pulsating flow of air. With varied pulsating amplitudes and frequencies, single-fiber deformation was investigated numerically using the fluid–structure interaction technique and verified with experimental data testing with a laser vibrometer. Then, the effect of pulsating amplitude and frequency on heat and mass transfer performance of the hollow fiber membrane was analyzed. The maximum fiber deformation along the airflow direction was far larger than that perpendicular to the flow direction. Compared with the case where the fiber did not vibrate, increasing the pulsation amplitude could strengthen Nu by 14–87%. Flow-induced fiber vibration could raise the heat transfer enhancement index from 13.8% to 80%. The pulsating frequency could also enhance the heat transfer of hollow fiber membranes due to the continuously weakened thermal boundary layer. With the increase in pulsating amplitude or frequency, the Sh number or Em under vibrating conditions can reach about twice its value under non-vibrating conditions.
Lipids in Pathophysiology and Development of the Membrane Lipid Therapy: New Bioactive Lipids
Authors: Torres Manuel , Parets Sebastià , Fernández-Díaz Javier , Beteta-Göbel Roberto , Rodríguez-Lorca Raquel , Román Ramón , Lladó Victoria , Rosselló Catalina A. , Fernández-García Paula , Escribá Pablo V.
Published: November 2021

Membranes are mainly composed of a lipid bilayer and proteins, constituting a checkpoint for the entry and passage of signals and other molecules. Their composition can be modulated by diet, pathophysiological processes, and nutritional/pharmaceutical interventions. In addition to their use as an energy source, lipids have important structural and functional roles, e.g., fatty acyl moieties in phospholipids have distinct impacts on human health depending on their saturation, carbon length, and isometry. These and other membrane lipids have quite specific effects on the lipid bilayer structure, which regulates the interaction with signaling proteins. Alterations to lipids have been associated with important diseases, and, consequently, normalization of these alterations or regulatory interventions that control membrane lipid composition have therapeutic potential. This approach, termed membrane lipid therapy or membrane lipid replacement, has emerged as a novel technology platform for nutraceutical interventions and drug discovery. Several clinical trials and therapeutic products have validated this technology based on the understanding of membrane structure and function. The present review analyzes the molecular basis of this innovative approach, describing how membrane lipid composition and structure affects protein-lipid interactions, cell signaling, disease, and therapy (e.g., fatigue and cardiovascular, neurodegenerative, tumor, infectious diseases).
A Driving Method for Reducing Oil Film Splitting in Electrowetting Displays
Authors: Zeng Wenjun , Yi Zichuan , Zhao Yiming , Wang Li , Zhang Jitao , Zhou Xichen , Liu Liming , Chi Feng , Yang Jianjun , Zhang Chongfu
Published: November 2021

Electrowetting displays (EWDs) are one of the most potential electronic papers. However, they have the problem of oil film splitting, which could lead to a low aperture ratio of EWDs. In this paper, a driving waveform was proposed to reduce oil film splitting. The driving waveform was composed of a rising stage and a driving stage. First, the rupture voltage of oil film was analyzed by testing the voltage characteristic curve of EWDs. Then, a quadratic function waveform with an initial voltage was applied at the rising stage to suppress oil film splitting. Finally, a square wave was applied at the driving stage to maintain the aperture ratio of EWDs. The experimental results show that the luminance was increased by 8.78% and the aperture ratio was increased by 4.47% compared with an exponential function driving waveform.
Seawater Desalination by Modified Membrane Distillation: Effect of Hydrophilic Surface Modifying Macromolecules Addition into PVDF Hollow Fiber Membrane
Authors: Purwanto Mochammad , Kusuma Nindita Cahya , Sudrajat Ma’rup Ali , Jaafar Juhana , Nasir Atikah Mohd , Aziz Mohd Haiqal Abd , Othman Mohd Hafiz Dzarfan , Rahman Mukhlis A , Raharjo Yanuardi , Widiastuti Nurul
Published: November 2021

Hollow fiber membranes of polyvinylidene fluoride (PVDF) were prepared by incorporating varying concentrations of hydrophilic surface-modifying macromolecules (LSMM) and a constant amount of polyethylene glycol (PEG) additives. The membranes were fabricated by the dry-wet spinning technique. The prepared hollow fiber membranes were dip-coated by hydrophobic surface-modifying macromolecules (BSMM) as the final step fabrication. The additives combination is aimed to produce hollow fiber membranes with high flux permeation and high salt rejection in the matter of seawater desalination application. This study prepares hollow fiber membranes from the formulation of 18 wt. % of PVDF mixed with 5 wt. % of PEG and 3, 4, and 5 wt. % of LSMM. The membranes are then dip-coated with 1 wt. % of BSMM. The effect of LSMM loading on hydrophobicity, morphology, average pore size, surface porosity, and membrane performance is investigated. Coating modification on LSMM membranes showed an increase in contact angle up to 57% of pure, unmodified PVDF/PEG membranes, which made the fabricated membranes at least passable when hydrophobicity was considered as one main characteristic. Furthermore, The PVDF/PEG/4LSMM-BSMM membrane exhibits 161 °C of melting point as characterized by the DSC. This value indicates an improvement of thermal behavior shows so as the fabricated membranes are desirable for membrane distillation operation conditions range. Based on the results, it can be concluded that PVDF/PEG membranes with the use of LSMM and BSMM combination could enhance the permeate flux up to 81.32 kg·m−2·h−1 at the maximum, with stable salt rejection around 99.9%, and these are found to be potential for seawater desalination application.
Low- and High-Pressure Membrane Separation in the Production of Process Water for Coke Quenching
Authors: Trusek Anna , Wajsprych Maciej , Noworyta Andrzej
Published: November 2021

Although the time for operating mines and coking plants in many countries is coming to an end due to climate change, we must still ensure that the pollution generated by this source of the economy is minimized. Despite the several stages of treatment of the coke-oven effluent, completed with nitrification and denitrification processes preceding final sedimentation, the stream obtained does not meet the requirements of water for coke quenching. That is why the stream after biodegradation and sedimentation was treated on membrane units to ensure water reusing in the coking plant. As the subjected stream contained both solid and dissolved pollutants, a two-stage system was proposed: low- and high-pressure membrane filtration. Industrial modules were tested on pilot units operating under industrial plant conditions. In the case of the ultrafiltration process, all the tested ultrafiltration modules fulfilled the primary task. All of them separated almost completely the turbidities present in the stream, which would have disturbed the operation of the high-pressure plant. Considering the decrease in permeate flux and the possibility of cleaning, a PCI membrane made of PVDF tubes with a diameter of 12.5 mm and pore size of 20 μm was selected. Regarding the high-pressure membrane filtration, the reverse osmosis membrane was significantly better in the removal efficiency of both organic and inorganic dissolved substances. An operating pressure of 3 MPa was chosen for the system. Hence, membrane processes, which are not used as stand-alone treatment units for coke-oven effluents, function well as a final treatment stage.
Study of Tissue-Specific Reactive Oxygen Species Formation by Cell Membrane Microarrays for the Characterization of Bioactive Compounds
Authors: Elexpe Ane , Nieto Nerea , Fernández-Cuétara Claudia , Domínguez-Fernández Celtia , Morera-Herreras Teresa , Torrecilla María , Miguélez Cristina , Laso Antonio , Ochoa Eneko , Bailen María , González-Coloma Azucena , Angulo-Barturen Iñigo , Astigarraga Egoitz , Barreda-Gómez Gabriel
Published: November 2021

The production of reactive oxygen species (ROS) increases considerably in situations of cellular stress, inducing lipid peroxidation and multiple alterations in proteins and nucleic acids. However, sensitivity to oxidative damage varies between organs and tissues depending on the triggering process. Certain drugs used in the treatment of diverse diseases such as malaria have side effects similar to those produced by oxidative damage, although no specific study has been conducted. For this purpose, cell membrane microarrays were developed and the superoxide production evoked by the mitochondrial activity was assayed in the presence of specific inhibitors: rotenone, antimycin A and azide. Once the protocol was set up on cell membrane isolated from rat brain areas, the effect of six antimalarial drugs (atovaquone, quinidine, doxycycline, mefloquine, artemisinin, and tafenoquine) and two essential oils (Rosmarinus officinalis and Origanum majoricum) were evaluated in multiple human samples. The basal activity was different depending on the type of tissue, the liver, jejunum and adrenal gland being the ones with the highest amount of superoxide. The antimalarial drugs studied showed specific behavior according to the type of human tissue analyzed, with atovaquone and quinidine producing the highest percentage of superoxide formation, and doxycycline the lowest. In conclusion, the analysis of superoxide production evaluated in cell membranes of a collection of human tissues allowed for the characterization of the safety profile of these antimalarial drugs against toxicity mediated by oxidative stress.
A Sulfonated Polyimide/Nafion Blend Membrane with High Proton Selectivity and Remarkable Stability for Vanadium Redox Flow Battery
Authors: Li Jinchao , Liu Jun , Xu Wenjie , Long Jun , Huang Wenheng , He Zhen , Liu Suqin , Zhang Yaping
Published: November 2021

A sulfonated polyimide (SPI)/Nafion blend membrane composed of a designed and synthesized SPI polymer and the commercial Nafion polymer is prepared by a facile solution casting method for vanadium redox flow battery (VRFB). Similar molecular structures of both SPI and Nafion provide good compatibility and complementarity of the blend membrane. ATR-FTIR, 1H-NMR, AFM, and SEM are used to gain insights on the chemical structure and morphology of the blend membrane. Fortunately, the chemical stability of the SPI/Nafion blend membrane is effectively improved compared with reported SPI-based membranes for VRFB applications. In cycling charge-discharge tests, the VRFB with the as-prepared SPI/Nafion blend membrane shows excellent battery efficiencies and operational stability. Above results indicate that the SPI/Nafion blend membrane is a promising candidate for VRFB application. This work opens up a new possibility for fabricating high-performance SPI-based blend membrane by introduction of a polymer with a similar molecular structure and special functional groups into the SPI polymer.
Real-Time Defects Analyses Using High-Speed Imaging during Aluminum Magnesium Alloy Laser Welding
Authors: Mihai Sabin , Chioibasu Diana , Mahmood Muhammad Arif , Duta Liviu , Leparoux Marc , Popescu Andrei C.
Published: November 2021

In this study a continuous wave Ytterbium-doped Yttrium Aluminum Garnet (Yb: YAG) disk laser has been used for welding of AlMg3 casted alloy. A high-speed imaging camera has been employed to record hot vapor plume features during the process. The purpose was to identify a mechanism of pores detection in real-time based on correlations between metallographic analyses and area/intensity of the hot vapor in various locations of the samples. The pores formation and especially the position of these pores had to be kept under control in order to weld thick samples. Based on the characterization of the hot vapor, it has been found that the increase of the vapor area that exceeded a threshold value (18.5 ± 1 mm2) was a sign of pores formation within the weld seam. For identification of the pores’ locations during welding, the monitored element was the hot vapor intensity. The hot vapor core spots having a grayscale level reaching 255 was associated with the formation of a local pore. These findings have been devised based on correlation between pores placement in welds cross-section microscopy images and the hot vapor plume features in those respective positions.
The Effect of Subsequent Stress-Induced Martensite Aging on the Viscoelastic Properties of Aged NiTiHf Polycrystals
Authors: Tagiltsev Anton I. , Panchenko Elena Y. , Timofeeva Ekaterina E. , Chumlyakov Yuriy I. , Marchenko Ekaterina S. , Karaman Ibrahim
Published: November 2021

This study investigated the effect of stress-induced martensite aging under tensile and compressive stresses on the functional and viscoelastic properties in Ni50.3Ti32.2Hf17.5 polycrystals containing dispersed H-phase particles up to 70 nm in size obtained by preliminary austenite aging at 873 K for 3 h. It was found that stress-induced martensite aging at 428 K for 12 h results in the appearance of a two-way shape memory effect of −0.5% in compression and +1.8% in tension. Moreover, a significant change in viscoelastic properties can be observed: an increase in internal friction (by 25%) and a change in elastic modulus in tensile samples. The increase in internal friction during martensitic transformation after stress-induced martensite aging is associated with the oriented growth of thermal-induced martensite. After stress-induced martensite aging, the elastic modulus of martensite (EM) increased by 8 GPa, and the elastic modulus of austenite (EA) decreased by 8 GPa. It was shown that stress-induced martensite aging strongly affects the functional and viscoelastic properties of material and can be used to control them.
Preparation of a Nickel Layer with Bell-Mouthed Macropores via the Dual-Template Method
Authors: Yang Ruishan , Yao Weiguo , Qian Guangguang , Dou Yanli
Published: November 2021

A relatively static and unique bubble template is successfully realized on a microporous substrate by controlling the surface tensions of the electrodeposit solution, and a nickel layer containing macropores is prepared using this bubble template. When the surface tension of the solution is 50.2 mN/m, the desired bubble template can be formed, there are fewer bubbles attached to other areas on the substrate, and a good nickel layer is obtained. In the analysis of the macropore formation process, it is found that the size of the bell-mouthed macropores can be tailored by changing the solution stirring speed or the current density to adjust the growth rate of the bubble template. The size change of a macropore is measured by the profile angle of the longitudinal macropore, section. As the solution stirring speed increases from 160 to 480 r/min, the angle range of the bell-mouthed macropores cross-sectional profile is increased from 21.0° to 44.3°. In addition, the angle range of the bell-mouthed macropore cross-sectional profile is increased from 39.3° to 46.3° with the current density increasing from 1 to 2.5 A/dm2. Different from the dynamic hydrogen bubble template, the bubble template implemented in this paper stays attached on the deposition and grows slowly, which is novel and interesting, and the nickel layer containing macropores prepared using this bubble template is applied in completely different fields.
Pressure Dependence of Structural and Mechanical Properties of Single-Crystal Tungsten: A Molecular Dynamics Study
Authors: Liu Xuepeng , Xu Kezhong , Zhai Hua
Published: November 2021

In the current study, molecular dynamics (MD) simulations were performed to study the pressure dependence of the structural and mechanical properties of single-crystal tungsten. The results show that single-crystal tungsten possesses noteworthy high-pressure stability and exhibits linear lattice contraction with increasing external pressure. Consistent with the results of the performed experiments, the predicted elastic moduli, including Young’s modulus, shear modulus, and bulk modulus, as well as Poisson’s ratio and Pugh’s modulus ratio, show a clear increasing trend with the increase in pressure. Under uniaxial tensile loading, the single-crystal tungsten at high pressures experiences a phase transition from BCC to FCC and other disordered structures, which results in a stripe-like morphology in the tungsten crystal. These results are expected to deepen our understanding of the high-pressure structural and mechanical behaviors of tungsten materials.
Fatigue and Fracture Behavior of Cryogenic Materials Applied to LNG Fuel Storage Tanks for Coastal Ships
Authors: Kim Tae-Yeob , Yoon Sung-Won , Kim Ji-Hoon , Kim Myung-Hyun
Published: November 2021

The aim of this study is to investigate the applicability of automatic plasma arc welding (PAW) to cryogenic materials used in liquefied natural gas (LNG) fuel storage tanks based on experimental data. The mechanical properties of the materials were tested at room and cryogenic temperatures to investigate the fatigue and fracture performances of weld joints made by PAW. In addition, the influence of welding parameters on the welded joints such as material types and temperature were considered in this experimental study. Based on the results obtained by this experimental study, it was observed that the experimental results of all materials at room and cryogenic temperatures satisfied all the requirements of each mechanical test. Finally, we propose the experimental results of PAW that can be used in the structural design of LNG fuel storage tank applications.
Enhancement of the Mechanical and Tribological Properties of Aluminum-Based Alloys Fabricated by SPS and Alloyed with Mo and Cr
Authors: Grigoriev Sergey N. , Mironov Alexander , Kuznetsova Ekaterina , Pristinskiy Yuri , Podrabinnik Pavel , Pinargote Nestor Washington Solís , Gershman Iosif , Peretyagin Pavel , Smirnov Anton
Published: November 2021

Multicomponent aluminum-based alloys doped with chromium (Cr) and molybdenum (Mo), fabricated by spark plasma sintering (SPS), derived from a powder mixture prepared by mechanical alloying, were studied in this work. The morphology of the pristine and worn surfaces was analyzed using a scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy system. The obtained alloys exhibited higher hardness (73 and 72) for the Al–Mo and Al–Cr alloys, respectively, compared to reference bronze. Besides improved hardness, SPS-sintered alloys also showed a lower value of the weight and linear wear and the highest score-resistance compared to bronze. The enhanced tribological behavior is related to the formation of secondary structures on the friction surfaces of rubbing pairs, which in turn reduce wear. For the first time, the present research has demonstrated the effectiveness of the addition of Mo and Cr for the fabrication of sintered multicomponent Al-based alloys with a tailored microstructure that induces the formation of secondary structures on the tribosurfaces due to the self-organization processes during friction.
Conductance Quantization Behavior in Pt/SiN/TaN RRAM Device for Multilevel Cell
Authors: Park Jongmin , Lee Seungwook , Lee Kisong , Kim Sungjun
Published: November 2021

In this work, we fabricated a Pt/SiN/TaN memristor device and characterized its resistive switching by controlling the compliance current and switching polarity. The chemical and material properties of SiN and TaN were investigated by X-ray photoelectron spectroscopy. Compared with the case of a high compliance current (5 mA), the resistive switching was more gradual in the set and reset processes when a low compliance current (1 mA) was applied by DC sweep and pulse train. In particular, low-power resistive switching was demonstrated in the first reset process, and was achieved by employing the negative differential resistance effect. Furthermore, conductance quantization was observed in the reset process upon decreasing the DC sweep speed. These results have the potential for multilevel cell (MLC) operation. Additionally, the conduction mechanism of the memristor device was investigated by I-V fitting.
Development of Rapidly-Quenched Al-Ge-Si Filler Alloys for the Joining of Stainless Steel AISI 304 and Aluminum Alloy AA6082
Authors: Ivannikov Alexander , Fedorov Vasilii , Abramov Anton , Penyaz Milena , Bachurina Diana , Uhlig Thomas , Suchkov Alexey , Wagner Guntram , Morokhov Pavel , Sevryukov Oleg
Published: November 2021

Aluminum alloys based on the Al-Ge-Si system with a germanium content of up to 40 wt.%, promising for the brazing of aluminum alloy AA6082 with the stainless steel AISI 304, were studied. The temperature characteristics and microstructural and mechanical properties of the filler alloys were systematically investigated. Differential scanning calorimetry showed that with an increase in the germanium content from 28.0 to 40.0 wt.%, the liquidus temperature of the filler alloys decreased from 514.8 to 474.3 °C. X-ray diffraction analysis and electron microscopy data showed that the foil of the filler alloys reveals a homogeneous structure. The ingots of the alloys contain two eutectics, the first of which consists of a solid solution of (Al, Ge) with a solid solution of (Ge, Si), and the second consists of a solid solution of (Al, Ge) with a solid solution based on (Ge). When the content of germanium increases from 28.0 to 40.0 wt.%, a separation of the faceted solid solution particles (Ge, Si) and an increase in their number could be observed. Nanohardness measurements showed that the (Ge, Si) and (Ge) solid solutions had similar nanohardness, with values of 11.6 and 10.2 GPa, respectively. Simultaneously, the Al solid solution and the intermetallic Al7Ge2Fe phase exhibited significantly lower nanohardness values of 0.7 and 6.7 GPa, respectively. Brinell hardness measurements showed that the ingots of the filler alloys were sufficiently ductile and had a hardness comparable to that of AA6082, which is used for brazing with AISI 304 stainless steel. The obtained results for the studied ingots and the rapidly quenched foils can be used to predict the forming structure of the seam after brazing and adjusted for diffusion processes occurring between the brazed materials and the studied filler alloys.
Quasi-Static, Dynamic Compressive Properties and Deformation Mechanisms of Ti-6Al-4V Alloy with Gradient Structure
Authors: Lei Lei , Zhao Yongqing , Zhao Qinyang , Xin Shewei , Wu Cong , Jia Weiju , Zeng Weidong
Published: November 2021

Gradient structure metals have good comprehensive properties of strength and toughness and are expected to improve the dynamic mechanical properties of materials. However, there are few studies on the dynamic mechanical properties of gradient structured materials, especially titanium alloys. Therefore, in this study, ultrasonic surface rolling is used to prepare a gradient structure layer on the surface of Ti-6Al-4V, and the quasi-static and dynamic compressive properties of coarse-grained Ti-6Al-4V (CG Ti64) and gradient-structured Ti-6Al-4V (GS Ti64) are investigated. The results show that a GS with a thickness of 293 µm is formed. The quasi-static compressive strength of GS Ti64 is higher than that of CG Ti64. Both CG Ti64 and GS Ti64 exhibit weak strain hardening effects and strain rate insensitivity during dynamic compression, and the compressive strength is not significantly improved. The lateral expansion of CG Ti64 is more obvious, while the lateral side of GS Ti64 is relatively straight, indicating that uniform deformation occurs in GS Ti64. The α phase in the GS produces dislocation cells and local deformation bands, and the lamellar structure is transformed into ultrafine crystals after dynamic compression. Both of them produce an adiabatic shear band under 2700 s−1, a large crack forms in CG Ti64, while GS Ti64 forms a small crack, indicating that GS Ti64 has better resistance to damage. The synergistic deformation of GS and CG promotes Ti-6Al-4V to obtain good dynamic mechanical properties.
About the Memory of Transformation-Induced Plasticity in 35NCD16 Carbon Steel Subjected to Various Thermomechanical Histories
Authors: Jimenez Jose , Taleb Lakhdar
Published: November 2021

This study deals with Transformation-Induced Plasticity (TRIP) observed in the martensitic transformation of 35NCD16 ferritic steel. In this study, TRIP tests were carried out for two different cases: First, after only free dilatometric (FD) tests, which is used as the reference test for the considered applied stress; second, with TRIP tests being performed similarly to the first case (same thermal cycle, same applied stress) but with pre-thermomechanical loading histories applied. Such histories may be FD tests, TRIP tests, elastoplastic history, etc. The comparison between the results of TRIP test (a) and TRIP test (b) indicates if TRIP holds the memory of the applied loading histories. The current obtained results tell us that TRIP does not hold any significant memory. During the martensite → austenite transformation, the material may present recovery from strain hardening. Waiting for more details about the physical phenomena responsible for the absence of TRIP memory, one can point out the importance of this result as it enables one to use the same specimen for several TRIP tests. However, this result must be validated using other combinations of loading histories (such as multiaxial and cyclic, among others).
Research on Hydraulic Push-Pull Bending Process of Ultra-Thin-Walled Tubes
Authors: Zhang Xin , Zhao Changcai , Du Bing , Chen Duan , Li Yang , Han Zhaojian
Published: November 2021

Due to their high strength, high performance, and lightweight characteristics, bent tubes are widely used in many high-end industries, such as aviation, aerospace, shipbuilding, automobile, and petrochemical industries. Ultra-thin-walled (thickness-to-diameter ratio t/D < 0.01) bent tubes are more prone to wrinkling, fracture, and cross-section distortion than ordinary bent tubes, which are difficult to form integrally by traditional bending processes. In this paper, a new bending process with combined loading of hydraulic pressure, push, and pull was proposed to provide a new method for the bending of ultra-thin-walled tube. This process is characterized by the ability to optimize the combination of push, pull, and internal pressure according to the actual bending process in order to minimize the wrinkling of ultra-thin-walled tube during bending. Based on ABAQUS finite element (FE) software, the FE model of the hydraulic push-pull bending process for ultra-thin-walled tube was established. The influence of internal pressure, die clearance, and friction coefficient on the forming quality of bent tubes was discussed, and the optimum process parameters were obtained. Bent tubes with an initial thickness of 0.3 mm, diameter of 60 mm, and bending radius of 165 mm were manufactured in experiments. Through the comparative analysis of experiment and simulation, the accuracy of the FE simulation was verified.
Gold Compounds Inhibit the Ca2+-ATPase Activity of Brain PMCA and Human Neuroblastoma SH-SY5Y Cells and Decrease Cell Viability
Authors: Berrocal Maria , Cordoba-Granados Juan J. , Carabineiro Sónia A. C. , Gutierrez-Merino Carlos , Aureliano Manuel , Mata Ana M.
Published: November 2021

Plasma membrane calcium ATPases (PMCA) are key proteins in the maintenance of calcium (Ca2+) homeostasis. Dysregulation of PMCA function is associated with several human pathologies, including neurodegenerative diseases, and, therefore, these proteins are potential drug targets to counteract those diseases. Gold compounds, namely of Au(I), are well-known for their therapeutic use in rheumatoid arthritis and other diseases for centuries. Herein, we report the ability of dichloro(2-pyridinecarboxylate)gold(III) (1), chlorotrimethylphosphinegold(I) (2), 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidenegold(I) chloride (3), and chlorotriphenylphosphinegold(I) (4) compounds to interfere with the Ca2+-ATPase activity of pig brain purified PMCA and with membranes from SH-SY5Y neuroblastoma cell cultures. The Au(III) compound (1) inhibits PMCA activity with the IC50 value of 4.9 µM, while Au(I) compounds (2, 3, and 4) inhibit the protein activity with IC50 values of 2.8, 21, and 0.9 µM, respectively. Regarding the native substrate MgATP, gold compounds 1 and 4 showed a non-competitive type of inhibition, whereas compounds 2 and 3 showed a mixed type of inhibition. All gold complexes showed cytotoxic effects on human neuroblastoma SH-SY5Y cells, although compounds 1 and 3 were more cytotoxic than compounds 2 and 4. In summary, this work shows that both Au (I and III) compounds are high-affinity inhibitors of the Ca2+-ATPase activity in purified PMCA fractions and in membranes from SH-SY5Y human neuroblastoma cells. Additionally, they exert strong cytotoxic effects.
Pesticides and Male Fertility: A Dangerous Crosstalk
Authors: Moreira Sílvia , Pereira Sara C. , Seco-Rovira Vicente , Oliveira Pedro F. , Alves Marco G. , Pereira Maria de Lourdes
Published: November 2021

In recent decades, an increasing incidence of male infertility has been reported. Interestingly, and considering that pesticides have been used for a long time, the high incidence of this pathological state is concomitant with the increasing use of these chemicals, suggesting they are contributors for the development of human infertility. Data from literature highlight the ability of certain pesticides and/or their metabolites to persist in the environment for long periods of time, as well as to bioaccumulate in the food chain, thus contributing for their chronic exposure. Furthermore, pesticides can act as endocrine disrupting chemicals (EDCs), interfering with the normal function of natural hormones (which are responsible for the regulation of the reproductive system), or even as obesogens, promoting obesity and associated comorbidities, like infertility. Several in vitro and in vivo studies have focused on the effects and possible mechanisms of action of these pesticides on the male reproductive system that cause sundry negative effects, even though through diverse mechanisms, but all may lead to infertility. In this review, we present an up-to-date overview and discussion of the effects, and the metabolic and molecular features of pesticides on somatic cells and germinal tissues that affect germ cell differentiation.
Translational Application of Fluorescent Molecular Probes for the Detection of Reactive Oxygen and Nitrogen Species Associated with Intestinal Reperfusion Injury
Authors: de Holanda Gustavo Sampaio , dos Santos Valença Samuel , Carra Amabile Maran , Lichtenberger Renata Cristina Lopes , de Castilho Bianca , Franco Olavo Borges , de Moraes João Alfredo , Schanaider Alberto
Published: November 2021

Acute mesenteric ischemia, caused by an abrupt interruption of blood flow in the mesenteric vessels, is associated with high mortality. When treated with surgical interventions or drugs to re-open the vascular lumen, the reperfusion process itself can inflict damage to the intestinal wall. Ischemia and reperfusion injury comprise complex mechanisms involving disarrangement of the splanchnic microcirculatory flow and impairment of the mitochondrial respiratory chain due to initial hypoxemia and subsequent oxidative stress during the reperfusion phase. This pathophysiologic process results in the production of large amounts of reactive oxygen (ROS) and nitrogen (RNS) species, which damage deoxyribonucleic acid, protein, lipids, and carbohydrates by autophagy, mitoptosis, necrosis, necroptosis, and apoptosis. Fluorescence-based systems using molecular probes have emerged as highly effective tools to monitor the concentrations and locations of these often short-lived ROS and RNS. The timely and accurate detection of both ROS and RNS by such an approach would help to identify early injury events associated with ischemia and reperfusion and increase overall clinical diagnostic sensitivity. This abstract describes the pathophysiology of intestinal ischemia and reperfusion and the early biological laboratory diagnosis using fluorescent molecular probes anticipating clinical decisions in the face of an extremely morbid disease.
Hemorheological Parameters in Diabetic Patients: Role of Glucose Lowering Therapies
Authors: Biro Katalin , Feher Gergely , Vekasi Judit , Kenyeres Peter , Toth Kalman , Koltai Katalin
Published: November 2021

Diabetes mellitus influences several important hemorheological parameters including blood viscosity, erythrocyte aggregation and deformability. In the present study, 159 type-2 diabetic patients and 25 healthy controls were involved. Patient’s age, body weight, body mass index (BMI), smoking habits, physical activity, history of cardiovascular diseases, current antidiabetic therapy and concomitant medication were recorded. Patients were grouped according to their antidiabetic treatment with insulin, or with one or more of the following antidiabetic drugs: metformin, sulfonylureas, acarbose, or no antidiabetic therapy. Hemorheological measurements (hematocrit, erythrocyte aggregation, plasma fibrinogen, whole blood and plasma viscosity), von Willebrand factor activity, and platelet aggregation measurements were performed. Platelet aggregation was investigated with the method of Born. Plasma viscosity and red blood cell aggregation were significatly higher in diabetes. No significant difference was found in hemorheological parameters between different antidiabetic regimens. Whole blood and plasma viscosity and red blood cell aggregation correlated with glucose levels but not with HbA1C levels. In conclusion, plasma and whole blood viscosity, as well as red blood cell aggregation appear to be associated with concurrent hyperglycemia, but not with the quality of glycemic control or the applied antidiabetic treatment. Platelet aggregation induced by ADP or epinephrine does not seem to be associated with diabetes even at subthreshold doses.
Application of Sebum Lipidomics to Biomarkers Discovery in Neurodegenerative Diseases
Authors: Briganti Stefania , Truglio Mauro , Angiolillo Antonella , Lombardo Salvatore , Leccese Deborah , Camera Emanuela , Picardo Mauro , Di Costanzo Alfonso
Published: November 2021

Lipidomics is strategic in the discovery of biomarkers of neurodegenerative diseases (NDDs). The skin surface lipidome bears the potential to provide biomarker candidates in the detection of pathological processes occurring in distal organs. We investigated the sebum composition to search diagnostic and, possibly, prognostic, biomarkers of Alzheimer’s disease (AD) and Parkinson’s disease (PD). The observational study included 64 subjects: 20 characterized as “probable AD with documented decline”, 20 as “clinically established PD”, and 24 healthy subjects (HS) of comparable age. The analysis of sebum by GCMS and TLC retrieved the amounts (µg) of 41 free fatty acids (FFAs), 7 fatty alcohols (FOHs), vitamin E, cholesterol, squalene, and total triglycerides (TGs) and wax esters (WEs). Distributions of sebum lipids in NDDs and healthy conditions were investigated with multivariate ANOVA-simultaneous component analysis (ASCA). The deranged sebum composition associated with the PD group showed incretion of most composing lipids compared to HS, whereas only two lipid species (vitamin E and FOH14:0) were discriminant of AD samples and presented lower levels than HS sebum. Thus, sebum lipid biosynthetic pathways are differently affected in PD and AD. The characteristic sebum bio-signatures detected support the value of sebum lipidomics in the biomarkers search in NDDs.
Metabolite and Bioactive Compounds Profiling of Meteora Sea Buckthorn Berries through High-Resolution NMR Analysis
Authors: Zompra Aikaterini A. , Chasapi Styliani A. , Karagkouni Evdokia C. , Karamouzi Eugenia , Panopoulos Panagiotis , Spyroulias Georgios A.
Published: November 2021

Sea buckthorn berries (Hippophaë rhamnoides L.) (SB) are considered as a fruit with a high nutritional value with a plethora of bioactive ingredients. The present work focusses on the analysis of the whole NMR metabolic profile of SB berries grown in an organic orchard of Meteora/Greece. In parallel, this study validates/highlights qualitative characteristics of the osmotic processed berries according to the fresh fruit. The composition in bioactive metabolites of SB berries was elucidated through sophisticated high-resolution NMR spectroscopy. The lipophilic profile maintains the vitamins, flavonoid glycosides, phenolic esters and the essential lipid components of SB, while the polar profile reveals a variety of flavonoids, saccharides, organic acids, amino acids and esterified glycosides. This approach towards identification of SB bioactive ingredients may serve as basis for simultaneous profiling and quality assessment and may be applied to monitor fresh food quality regarding other food preservation methods.
Dynamic pH and Thermal Analysis of Paper-Based Microchip Electrophoresis
Authors: Hasan Muhammad Noman , An Ran , Akkus Asya , Akkaynak Derya , Minerick Adrienne R. , Kharangate Chirag R. , Gurkan Umut A.
Published: November 2021

Paper-based microchip electrophoresis has the potential to bring laboratory electrophoresis tests to the point of need. However, high electric potential and current values induce pH and temperature shifts, which may affect biomolecule electrophoretic mobility thus decrease test reproducibility and accuracy of paper-based microfluidic electrophoresis. We have previously developed a microchip electrophoresis system, HemeChip, which has the capability of providing low-cost, rapid, reproducible, and accurate point-of-care (POC) electrophoresis tests for hemoglobin analysis. Here, we report the methodologies we implemented for characterizing HemeChip system pH and temperature during the development process, including utilizing commercially available universal pH indicator and digital camera pH shift characterization, and infrared camera characterizing temperature shift characterization. The characterization results demonstrated that pH shifts up to 1.1 units, a pH gradient up to 0.11 units/mm, temperature shifts up to 40 °C, and a temperature gradient up to 0.5 °C/mm existed in the system. Finally, we report an acid pre-treatment of the separation media, a cellulose acetate paper, mitigated both pH and temperature shifts and provided a stable environment for reproducible HemeChip hemoglobin electrophoresis separation.
Total Harmonic Distortion of a Piezoelectric MEMS Loudspeaker in an IEC 60318-4 Coupler Estimation Using Static Measurements and a Nonlinear State Space Model
Authors: Liechti Romain , Durand Stéphane , Hilt Thierry , Casset Fabrice , Poulain Christophe , Le Rhun Gwenaël , Pavageau Franklin , Kuentz Hugo , Colin Mikaël
Published: November 2021

We propose a method to evaluate the Total Harmonic Distortion generated by a cantilever-based PZT loudspeaker inside an IEC 60318-4 coupler. The model is validated using experimental data of a commercial loudspeaker. Using the time domain equations of the equivalent electrical circuit of the loudspeaker inside the coupler and a state space formulation, the acoustic pressure response is calculated and compared to the measurement of the manufacturer. Next, the stiffness, transduction and capacitance nonlinear functions are evaluated with a Double-Beam Laser Interferometer (DBLI) and a nanoindenter on test devices and on the commercial loudspeaker. By introducing the nonlinear functions into the model as amplitude-dependent parameters, the THD generated by the loudspeaker is calculated and compared to the value provided by the manufacturer. The good agreement between the measurement and the simulation could allow for a rather quick simulation of the performance of similarly designed loudspeakers at the early stage of the design, by only estimating the static linearity of the main nonlinearity sources.
ADRC-Based Control Method for the Vascular Intervention Master–Slave Surgical Robotic System
Authors: Zhou Wei , Guo Shuxiang , Guo Jin , Meng Fanxu , Chen Zhengyang
Published: November 2021

In vascular interventional surgery, surgeons operate guidewires and catheters to diagnose and treat patients with the assistance of the digital subtraction angiography (DSA). Therefore, the surgeon will be exposed to X-rays for extended periods. To protect the surgeon, the development of a robot-assisted surgical system is of great significance. The displacement tracking accuracy is the most important issue to be considered in the development of the system. In this study, the active disturbance rejection control (ADRC) method is applied to guarantee displacement tracking accuracy. First, the core contents of the proportional–integral–derivative (PID) and ADRC methods are analyzed. Second, comparative evaluation experiments for incremental PID and ADRC methods are presented. The results show that the ADRC method has better performance of than that of the incremental PID method. Finally, the calibration experiments for the ADRC control method are implemented using the master–slave robotic system. These experiments demonstrate that the maximum tracking error is 0.87 mm using the ADRC method, effectively guaranteeing surgical safety.
Simulation, Modeling and Experimental Research on the Thermal Effect of the Motion Error of Hydrostatic Guideways
Authors: Lei Pengli , Wang Zhenzhong , Shi Chenchun , Peng Yunfeng , Lu Feng
Published: November 2021

Hydrostatic guideways are widely applied in ultra-precision machine tools, and motion errors undermine the machining accuracy. Among all the influence factors, the thermal effect distributes most to motion errors. Based on the kinematic theory and the finite element method, a 3-degrees-of-freedom quasi-static kinematics model for motion errors containing the thermal effect was established. In this model, the initial state of the closed rail as a “black box” is regarded, and a self-consistent setting method for the initial state of the guide rails is proposed. Experiments were carried out to verify the thermal motion errors simulated by the finite element method and our kinematics model. The deviation of the measured thermal vertical straightness error from the theoretical value is less than 1 μm, which ensured the effectiveness of the model we developed.
Investigation of the Feasibility of Ventricular Delivery of Resveratrol to the Microelectrode Tissue Interface
Authors: Kim Youjoung , Ereifej Evon S. , Schwartzman William E. , Meade Seth M. , Chen Keying , Rayyan Jacob , Feng He , Aluri Varoon , Mueller Natalie N. , Bhambra Raman , Bhambra Sahaj , Taylor Dawn M. , Capadona Jeffrey R.
Published: November 2021

(1) Background: Intracortical microelectrodes (IMEs) are essential to basic brain research and clinical brain–machine interfacing applications. However, the foreign body response to IMEs results in chronic inflammation and an increase in levels of reactive oxygen and nitrogen species (ROS/RNS). The current study builds on our previous work, by testing a new delivery method of a promising antioxidant as a means of extending intracortical microelectrodes performance. While resveratrol has shown efficacy in improving tissue response, chronic delivery has proven difficult because of its low solubility in water and low bioavailability due to extensive first pass metabolism. (2) Methods: Investigation of an intraventricular delivery of resveratrol in rats was performed herein to circumvent bioavailability hurdles of resveratrol delivery to the brain. (3) Results: Intraventricular delivery of resveratrol in rats delivered resveratrol to the electrode interface. However, intraventricular delivery did not have a significant impact on electrophysiological recordings over the six-week study. Histological findings indicated that rats receiving intraventricular delivery of resveratrol had a decrease of oxidative stress, yet other biomarkers of inflammation were found to be not significantly different from control groups. However, investigation of the bioavailability of resveratrol indicated a decrease in resveratrol accumulation in the brain with time coupled with inconsistent drug elution from the cannulas. Further inspection showed that there may be tissue or cellular debris clogging the cannulas, resulting in variable elution, which may have impacted the results of the study. (4) Conclusions: These results indicate that the intraventricular delivery approach described herein needs further optimization, or may not be well suited for this application.