866 results match your criteria dense pores


Experimental Study on the Salt Freezing Durability of Multi-Walled Carbon Nanotube Ultra-High-Performance Concrete.

Materials (Basel) 2022 Apr 28;15(9). Epub 2022 Apr 28.

Department of Civil Engineering, Changzhou University, Changzhou 213164, China.

Ultra-high-performance concrete (UHPC) is a new type of high-performance cement-based composite. It is widely used in important buildings, bridges, national defense construction, etc. because of its excellent mechanical properties and durability. Read More

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Evaluation of Mechanical and Microstructural Properties and Global Warming Potential of Green Concrete with Wheat Straw Ash and Silica Fume.

Materials (Basel) 2022 Apr 27;15(9). Epub 2022 Apr 27.

Al Bilad Bank Scholarly Chair for Food Security in Saudi Arabia, The Deanship of Scientific Research, The Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Al-Ahsa 31982, Saudi Arabia.

Cement and concrete are among the major contributors to CO emissions in modern society. Researchers have been investigating the possibility of replacing cement with industrial waste in concrete production to reduce its environmental impact. Therefore, the focus of this paper is on the effective use of wheat straw ash (WSA) together with silica fume (SF) as a cement substitute to produce high-performance and sustainable concrete. Read More

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Influence of Femtosecond Laser Modification on Biomechanical and Biofunctional Behavior of Porous Titanium Substrates.

Materials (Basel) 2022 Apr 19;15(9). Epub 2022 Apr 19.

Departamento de Ingeniería y Ciencia de los Materiales y del Transporte, Escuela Politécnica Superior, Universidad de Sevilla, 41011 Seville, Spain.

Bone resorption and inadequate osseointegration are considered the main problems of titanium implants. In this investigation, the texture and surface roughness of porous titanium samples obtained by the space holder technique were modified with a femtosecond Yb-doped fiber laser. Different percentages of porosity (30, 40, 50, and 60 vol. Read More

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Boundary-Monte Carlo Method for Neutral and Charged Confined Fluids.

J Chem Theory Comput 2022 May 16. Epub 2022 May 16.

School of Science, University of New South Wales, Canberra, Canberra ACT 2600, Australia.

In this work, we describe a new Monte Carlo (MC) simulation method to investigate highly coupled fluids in confined geometries at a constant chemical potential. This method is based on so-called multi-scale Hamiltonian methods, wherein the chemical potential is determined using a more amenable Hamiltonian for a fluid in an "outer" region, which facilitates standard methods, such as grand canonical MC simulations or Widom's particle insertion method. The (inner region) fluid of interest is placed in diffusive contact with the simpler outer fluid via a boundary zone wherein the Hamiltonian is transformed. Read More

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Silicalite-1/PDMS Hybrid Membranes on Porous PVDF Supports: Preparation, Structure and Pervaporation Separation of Dichlorobenzene Isomers.

Polymers (Basel) 2022 Apr 21;14(9). Epub 2022 Apr 21.

Institute of Photonics & Bio-Medicine, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.

Separation of dichlorobenzene (DCB) isomers with high purity by time- and energy-saving methods from their mixtures is still a great challenge in the fine chemical industry. Herein, silicalite-1 zeolites/polydimethylsiloxane (PDMS) hybrid membranes (silicalite-1/PDMS) have been successfully fabricated on the porous polyvinylidene fluoride (PVDF) supports to first investigate the pervaporation separation properties of DCB isomers. The morphology and structure of the silicalite-1 zeolites and the silicalite-1/PDMS/PVDF hybrid membranes were characterized by XRD, FTIR, SEM and BET. Read More

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Ultrafast Porous Carbon Activation Promises High-Energy Density Supercapacitors.

Small 2022 May 12:e2200954. Epub 2022 May 12.

School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China.

Activated porous carbons (APCs) are traditionally produced by heat treatment and KOH activation, where the production time can be as long as 2 h, and the produced activated porous carbons suffer from relatively low specific surface area and porosity. In this study, the fast high-temperature shock (HTS) carbonization and HTS-KOH activation method to synthesize activated porous carbons with high specific surface area of ≈843 m g , is proposed. During the HTS process, the instant Joule heating (at a heating speed of ≈1100 K s ) with high temperature and rapid quenching can effectively produce abundant pores with homogeneous size-distribution due to the instant melt of KOH into small droplets, which facilitates the interaction between carbon and KOH to form controllable, dense, and small pores. Read More

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Interaction mechanism between soybean protein isolate and citrus pectin.

J Food Sci 2022 May 5. Epub 2022 May 5.

Heilongjiang Bayi Agricultural University Food College, Daqing, China.

In this study, citrus pectin (CP) and soybean protein isolate (SPI) were used as raw materials to prepare a complex. The interaction mechanism and structural changes between SPI and CP were deeply studied by fluorescence spectroscopy and Fourier infrared spectroscopy. The results show that CP has a strong quenching effect on SPI's endogenous fluorescence, and with the addition of CP, the endogenous fluorescence intensity of SPI decreased from 13,565. Read More

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Enhanced removal of Pb from electrolytic manganese anode slime and preparation of chemical MnO.

Environ Technol 2022 Apr 28:1-22. Epub 2022 Apr 28.

South Manganese Group Limited, Nanning, Guangxi 530022, China.

Electrolytic manganese anode slime (EMAS) is produced during the production of electrolytic manganese metal. In this study, a method based on vacuum carbothermal reduction was used for Pb removal in EMAS. A Pb-removal efficiency of 99. Read More

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Effect of Pore Shape on Mechanical Properties of Porous Shape Memory Alloy.

Micromachines (Basel) 2022 Mar 31;13(4). Epub 2022 Mar 31.

Aviation Engineering Institute, Civil Aviation University of China, Tianjin 300300, China.

Porous shape memory alloys (SMAs) have been widely used in the aerospace, military, medical, and health fields due to its unique mechanical properties such as superelasticity, biocompatibility, and shape memory effect. In this work, the pore shape was considered in the constitutive model of the porous SMAs by respectively introducing the parameter of aspect ratio and for different pore shapes including oblate, sphere, and prolate shapes, so the expression of Young's modulus for the porous SMA can be derived. Then, the constitutive model for such a porous shape memory alloy was established. Read More

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Discrete Element Modeling of Instability Mechanisms of Unbound Permeable Aggregate Base Materials in Triaxial Compression.

Materials (Basel) 2022 Apr 7;15(8). Epub 2022 Apr 7.

School of Railway Engineering, Hunan Technical College of Railway High-Speed, Hengyang 421002, China.

Unbound permeable aggregate base (UPAB) materials with strong load-transmitting skeleton yet adequate inter-connected pores are desired for use in the sponge-city initiative. However, the micro-scale fabric evolution and instability mechanism of macroscopic strength behavior of such UPAB materials still remain unclear. In this study, virtual monotonic triaxial compression tests were conducted by using the discrete element method (DEM) modeling approach on specimens with different gradations quantified by the parameter of gravel-to-sand ratio (G/S). Read More

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Cell division in tissues enables macrophage infiltration.

Science 2022 04 21;376(6591):394-396. Epub 2022 Apr 21.

Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria.

Cells migrate through crowded microenvironments within tissues during normal development, immune response, and cancer metastasis. Although migration through pores and tracks in the extracellular matrix (ECM) has been well studied, little is known about cellular traversal into confining cell-dense tissues. We find that embryonic tissue invasion by macrophages requires division of an epithelial ectodermal cell at the site of entry. Read More

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Benefit of coconut-based hair oil via hair porosity quantification.

Int J Cosmet Sci 2022 Apr 4. Epub 2022 Apr 4.

Kamath Consulting Inc, Princeton, New Jersey, USA.

Objective: The present study is intended to characterize the surfactant damage suffered by the hair cortex in routine washing and the mechanistic effect of Coconut Based Hair Oils (CBHO) to mitigate the damage.

Methods: Surfactants which diffuse into the hair structure solubilize protein moieties, leading to an increase in porosity and internal surface area as well as the pore volume. The changes in hair pores occurring in the hair cortex are measured by nitrogen sorption method in line with the Brunauer-Emmett-Teller (BET) theory. Read More

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A SERS platform based on diatomite modified by gold nanoparticles using a combination of layer-by-layer assembly and a freezing-induced loading method.

Phys Chem Chem Phys 2022 Apr 13;24(15):8901-8912. Epub 2022 Apr 13.

Center for Photonic Science and Engineering, Skolkovo Institute of Science and Technology, 3 Nobel Str., Moscow, 121205, Russia.

Siliceous diatom frustules represent an up-and-coming platform for a range of bio-assisted nanofabrication processes able to overcome the complexity and high cost of current engineering technology solutions in terms of negligibly small power consumption and environmentally friendly processing combined with unique highly porous structures and properties. Herein, the modification of diatomite - a soft, loose, and fine-grained siliceous sedimentary rock composed of the remains of fossilized diatoms - with gold nanoparticles using layer-by-layer technology in combination with a freezing-induced loading approach is demonstrated. The obtained composite structures are characterized by dynamic light scattering, extinction spectroscopy, scanning (SEM) and transmission electron microscopy (TEM), and photoacoustic imaging techniques, and tested as a platform for surface-enhanced Raman scattering (SERS) using Rhodamine 6G. Read More

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Manufacturing of Open-Cell Aluminium Foams: Comparing the Sponge Replication Technique and Its Combination with the Freezing Method.

Materials (Basel) 2022 Mar 15;15(6). Epub 2022 Mar 15.

Department of Mechanical Engineering, Institute for Materials and Joining Technology, Otto-von-Guericke-University Magdeburg, Große Steinernetischstraße 6, 39104 Magdeburg, Germany.

The manufacturing of aluminium foams with a total porosity of 87% using the sponge replication method and a combination of the sponge replication and freezing technique is presented. Foams with different cell counts were prepared from polyurethane (PU) templates with a pore count per inch (ppi) of 10, 20 and 30; consolidation of the foams was performed in an argon atmosphere at 650 °C. The additional freezing steps resulted in lamellar pores in the foam struts. Read More

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Epithelial folding of alveolar cells derived from human induced pluripotent stem cells on artificial basement membrane.

Acta Biomater 2022 Mar 16. Epub 2022 Mar 16.

PASTEUR, Département de Chimie, École Normale Supérieure, CNRS, PSL University, Sorbonne Université, Paris 75005, France. Electronic address:

Epithelial folding depends on mechanical properties of both epithelial cells and underlying basement membrane (BM). While folding is essential for tissue morphogenesis and functions, it is difficult to recapitulate features of a growing epithelial monolayer for in vitro modeling due to lack of in vivo like BM. Herein, we report a method to overcome this difficulty by culturing on an artificial basement membrane (ABM) the primordial lung progenitors (PLPs) from human induced pluripotent stem cells (hiPSCs). Read More

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The root-like chitosan nanofiber porous scaffold cross-linked by genipin with type I collagen and its osteoblast compatibility.

Carbohydr Polym 2022 Jun 17;285:119255. Epub 2022 Feb 17.

School of Food Science and Engineering, South China University of Technology, Guangzhou 510644, China. Electronic address:

Bone tissue repair is difficult due to the dense structure of the extracellular matrix. To solve this problem, a porous chitosan nanofiber scaffold (CSNFS) with an extracellular matrix-like structure was prepared via a facile cross-linked reaction of root-like chitosan nanofiber (CSNF) and collagen (Col) by using genipin (Gen) as the cross-linker. The optimal preparation conditions of CSNFS is weight ratio of CSNF:Col:Gen =1:1:0. Read More

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Effects of the Separator MOF-AlO Coating on Battery Rate Performance and Solid-Electrolyte Interphase Formation.

ACS Appl Mater Interfaces 2022 Mar 11;14(11):13722-13732. Epub 2022 Mar 11.

Technical Institute of Physics and Chemistry, Chinese Academy of Science, 29 Zhong-guan-cun East Road, Haidian District, Beijing 100190, P. R. China.

Metal organic frameworks (MOFs) have unique advantages in optimizing the ionic conductivity of battery separators because of their rich cavity structure and highly ordered and connected pores. In this study, we used a hydrothermal method to synthesize a functional material, Ag-MOF crystal, as a separator coating content, and then studied the properties and application effect of the MOF-AlO-blended coating applying to a polyethylene (PE) separator (MOFAl/PE). Results show that MOFAl/PE (MOF/AlO = 0. Read More

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Synthesis of various dimensional metal organic frameworks (MOFs) and their hybrid composites for emerging applications - A review.

Chemosphere 2022 Jul 7;298:134184. Epub 2022 Mar 7.

Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Poonamallee High Road, Velappanchavadi, Chennai, 600 077, Tamil Nadu, India. Electronic address:

Metal organic frameworks (MOFs) represent the organic and inorganic hybrid porous materials. MOFs are low dense and highly porous materials which in turn provide large surface area that can accumulate and store numerous molecules within the pores. The pore size may also act as a mesh to separate molecules. Read More

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Surface-Enhanced Raman Scattering from Dye Molecules in Silicon Nanowire Structures Decorated by Gold Nanoparticles.

Int J Mol Sci 2022 Feb 26;23(5). Epub 2022 Feb 26.

Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.

Silicon nanowires (SiNWs) prepared by metal-assisted chemical etching of crystalline silicon wafers followed by deposition of plasmonic gold (Au) nanoparticles (NPs) were explored as templates for surface-enhanced Raman scattering (SERS) from probe molecules of Methylene blue and Rhodamine B. The filling factor by pores (porosity) of SiNW arrays was found to control the SERS efficiency, and the maximal enhancement was observed for the samples with porosity of 55%, which corresponded to dense arrays of SiNWs. The obtained results are discussed in terms of the electromagnetic enhancement of SERS related to the localized surface plasmon resonances in Au-NPs on SiNW's surfaces accompanied with light scattering in the SiNW arrays. Read More

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February 2022

Function of the Nuclear Transport Machinery in Maintaining the Distinctive Compositions of the Nucleus and Cytoplasm.

Authors:
Murray Stewart

Int J Mol Sci 2022 Feb 25;23(5). Epub 2022 Feb 25.

MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.

Although the separation of transcription and translation, mediated by the nuclear envelope, is the defining characteristic of Eukaryotes, the barrier between the nuclear and cytoplasmic compartments needs to be semipermeable to enable material to be moved between them. Moreover, each compartment needs to have a distinctive complement of macromolecules to mediate specific functions and so movement between them needs to be controlled. This is achieved through the selective active transport of macromolecules through the nuclear pores that stud the nuclear envelope, and which serve as a conduit between these compartments. Read More

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February 2022

Ultrahigh-Strength Porous Ceramic Composites via a Simple Directional Solidification Process.

Nano Lett 2022 Mar 8;22(6):2405-2411. Epub 2022 Mar 8.

State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, P. R. China.

Porous ceramics possess great application potential in various fields. However, the contradiction between their pores and their strength have significantly hampered their applications. In this study, we present a simple directional solidification process that relies on its in situ pore forming mechanism to fabricate AlO/YAlO/ZrO porous eutectic ceramic composites with a highly dense and nanostructured eutectic skeleton matrix and a lotus-type porous structure. Read More

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Developing Fused Deposition Modeling Additive Manufacturing Processing Strategies for Aluminum Alloy 7075: Sample Preparation and Metallographic Characterization.

Materials (Basel) 2022 Feb 11;15(4). Epub 2022 Feb 11.

Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.

Currently, no commercial aluminum 7000 series filaments are available for making aluminum parts using fused deposition modeling (FDM)-based additive manufacturing (AM). The key technical challenge associated with the FDM of aluminum alloy parts is consolidating the loosely packed alloy powders in the brown-body, separated by thin layers of surface oxides and polymer binders, into a dense structure. Classical pressing and sintering-based powder metallurgy (P/M) technologies are employed in this study to assist the development of FDM processing strategies for making strong Al7075 AM parts. Read More

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February 2022

Healing effect of carboxymethyl chitosan-plantamajoside hydrogel on burn wound skin.

Burns 2022 Jan 29. Epub 2022 Jan 29.

Department of Orthopedics, Shengjing Hospital of China Medical University, No. 36 Sanhao Road, Heping District, Shenyang l10004, China. Electronic address:

Background: It is known that hydrogels based on carboxymethyl chitosan (CMCS) have properties controling microbial growth, reducing inflammatory cell infiltration, and promoting collagen deposition. Plantamajoside (PMS), a natural Chinese herbal medicine with biological activity, has the properties of reducing inflammation, anti-oxidation, and promoting wound healing. However, the effects of carboxymethyl chitosan/plantamajoside hydrogel on partial thickness burn wounds remain unclear. Read More

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January 2022

Corrosion behavior and degradation mechanism of micro-extruded 3D printed ordered pore topological Fe scaffolds.

J Biomed Mater Res B Appl Biomater 2022 Jun 3;110(6):1439-1459. Epub 2022 Feb 3.

Department of Mechanical Engineering, Indian Institute of Technology, Delhi, India.

The fabrication of ordered pore topological structures (OPTS) with an improved biodegradation profile offers unique attributes required for bone reconstruction. These attributes consisted of fully interconnected porous structure, bone-mimicking mechanical properties, and the possibility of fully regenerating bony defects. Most of the biomaterials based on magnesium were associated with the problem of too fast degradation rate. Read More

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Use of Boundary-Driven Nonequilibrium Molecular Dynamics for Determining Transport Diffusivities of Multicomponent Mixtures in Nanoporous Materials.

J Phys Chem B 2022 Feb 1;126(5):1085-1100. Epub 2022 Feb 1.

Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom.

The boundary-driven molecular modeling strategy to evaluate mass transport coefficients of fluids in nanoconfined media is revisited and expanded to multicomponent mixtures. The method requires setting up a simulation with bulk fluid reservoirs upstream and downstream of a porous media. A fluid flow is induced by applying an external force at the periodic boundary between the upstream and downstream reservoirs. Read More

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February 2022

Structure of shear-induced platelet aggregated clot formed in an in vitro arterial thrombosis model.

Blood Adv 2022 May;6(9):2872-2883

George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA.

The structure of occlusive arterial thrombi is described herein. Macroscopic thrombi were made from whole blood in a collagen-coated, large-scale stenosis model with high shear flow similar to an atherosclerotic artery. The millimeter-sized thrombi were harvested for histology and scanning electron microscopy. Read More

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Polyamide-based membranes with structural homogeneity for ultrafast molecular sieving.

Nat Commun 2022 Jan 25;13(1):500. Epub 2022 Jan 25.

Key Laboratory of Material Chemistry for Energy Conversion and Storage (Huazhong University of Science and Technology), Ministry of Education, Wuhan, 430074, China.

Thin-film composite membranes formed by conventional interfacial polymerization generally suffer from the depth heterogeneity of the polyamide layer, i.e., nonuniformly distributed free volume pores, leading to the inefficient permselectivity. Read More

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January 2022

Fully connected network with multi-scale dilation convolution module in evaluating atrial septal defect based on MRI segmentation.

Comput Methods Programs Biomed 2022 Mar 11;215:106608. Epub 2022 Jan 11.

Faculty of Mathematics and Computer Science, Quanzhou Normal University, Quanzhou, 362000, China; Fujian Provincial Key Laboratory of Data Intensive Computing, Quanzhou 362000, China; Key Laboratory of Intelligent Computing and Information Processing, Fujian Province University, Quanzhou 362000, China. Electronic address:

Background And Objective: Atrial septal defect (ASD) is a common congenital heart disease. During embryonic development, abnormal atrial septal development leads to pores between the left and right atria. ASD accounts for the largest proportion of congenital heart disease. Read More

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Preparation and evaluation of a silk fibroin-polycaprolactone biodegradable biomimetic tracheal scaffold.

J Biomed Mater Res B Appl Biomater 2022 Jun 21;110(6):1292-1305. Epub 2022 Jan 21.

Department of Pediatrics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.

In tracheal tissue engineering, the construction of tracheal scaffolds with adequate biodegradable mechanical capacity and biological functions that mimic the structure of a natural trachea is challenging. To explore the feasibility of preparing biomimetic degradable scaffolds with C-type cartilage rings and an inner tracheal wall of polycaprolactone and silk fibroin. A mold was made according to the diameter of a rabbit trachea, and a silk fibroin tube and polycaprolactone ring attached to the tube were obtained by solution casting. Read More

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Borazatruxenes as precursors for hybrid C-BN 2D molecular networks.

Nanoscale 2022 Feb 3;14(5):1929-1943. Epub 2022 Feb 3.

Department of Physics, University of Bath, Bath, UK.

Synthesizing atomically thin, crystalline two-dimensional (2D) molecular materials which combine carbon with other elements is an emerging field requiring both custom-designed molecular precursors and their ability to organize into networks (hydrogen-bonded or covalent). Hybrid carbon-boron nitride (C-BN) networks face the additional challenge of needing hydrolytically-stable BN-containing molecular precursors. Here, we show that borazatruxenes (truxene-like molecules with a borazine core) and their halogenated derivatives are highly stable precursors suitable for on-surface assembly. Read More

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February 2022