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Rock Engineering

Liang Ma, Cheng Huang, Zhong-Sheng Liu, Kevin A Morin, Mike Aziz, Cody Meints
Geochemical reactions taking place at the rock surface and pore water interface, and rapid preferential water flow through waste rock piles are identified as two primary steps for acid rock drainage (ARD) and metal leaching (ML) processes. This paper (Part I) develops a water film model to describe the interactions among sulphide minerals, pore water and oxygen, which considers the reactive surface areas as the primary sites to capture geochemical reactions including sulphide oxidation and neutralization reactions, and also considers acid and metal ion storage in pore water...
December 6, 2018: Journal of Contaminant Hydrology
Jonathan Barés, Daniel Bonamy
Crack growth is the basic mechanism leading to the failure of brittle materials. Engineering addresses this problem within the framework of continuum mechanics, which links deterministically the crack motion to the applied loading. Such an idealization, however, fails in several situations and in particular cannot capture the highly erratic (earthquake-like) dynamics sometimes observed in slowly fracturing heterogeneous solids. Here, we examine this problem by means of innovative experiments of crack growth in artificial rocks of controlled microstructure...
November 26, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Hiroyoshi Y Tanaka, Kentaro Kitahara, Naoki Sasaki, Natsumi Nakao, Kae Sato, Hirokazu Narita, Hiroshi Shimoda, Michiya Matsusaki, Hiroshi Nishihara, Atsushi Masamune, Mitsunobu R Kano
Desmoplasia is a hallmark of pancreatic cancer and consists of fibrotic cells and secreted extracellular matrix (ECM) components. Various in vitro three-dimensional (3D) models of desmoplasia have been reported, but little is known about the relevant thickness of the engineered fibrotic tissue. We thus measured the thickness of fibrotic tissue in human pancreatic cancer, as defined by the distance from the blood vessel wall to tumor cells. We then generated a 3D fibrosis model with a thickness reaching the clinically observed range using pancreatic stellate cells (PSCs), the main cellular constituent of pancreatic cancer desmoplasia...
November 17, 2018: Biomaterials
Abdulhameed Al-Ghabkari, Lori D Moffat, Michael P Walsh, Justin A MacDonald
Zipper-interacting protein kinase (ZIPK) is a Ser/Thr kinase that mediates a variety of cellular functions. Analogue-sensitive kinase technology was applied to the study of ZIPK signaling in coronary artery smooth muscle cells. ZIPK was engineered in the ATP-binding pocket by substitution of a bulky gatekeeper amino acid (Leu93) with glycine. Cell-permeable derivatives of pyrazolo[3,4-d]pyrimidine provided effective inhibition of L93G-ZIPK (1NM-PP1, IC50 , 1.0 μM; 3MB-PP1, IC50 , 2.0 μM; and 1NA-PP1, IC50 , 8...
November 1, 2018: Proteins
Gavin T Knight, Brady F Lundin, Nisha Iyer, Lydia Mt Ashton, William A Sethares, Rebecca M Willett, Randolph Scott Ashton
Human pluripotent stem cell (hPSC)-derived neural organoids display unprecedented emergent properties. Yet in contrast to the singular neuroepithelial tube from which the entire central nervous system (CNS) develops in vivo, current organoid protocols yield tissues with multiple neuroepithelial units, a.k.a. neural rosettes, each acting as independent morphogenesis centers and thereby confounding coordinated, reproducible tissue development. Here, we discover that controlling initial tissue morphology can effectively (>80%) induce single neural rosette emergence within hPSC-derived forebrain and spinal tissues...
October 29, 2018: ELife
Yara A Alzahid, Peyman Mostaghimi, Alireza Gerami, Ankita Singh, Karen Privat, Tammy Amirian, Ryan T Armstrong
Fluid flow in porous rocks is commonly capillary driven and thus, dependent on the surface characteristics of rock grains and in particular the connectivity of corners and crevices in which fluids reside. Traditional microfluidic fabrication techniques do not provide a connected pathway of crevices that are essential to mimic multiphase flow in rocks. Here, geo-material microfluidic devices with connected pathways of corners and crevices were created by functionalising Polydimethylsiloxane (PDMS) with rock minerals...
October 19, 2018: Scientific Reports
Jeffrey T Wright, Zachary C Holmes, James E Byers
Ecosystem engineers are predicted to have stronger facilitative effects when environmental stress is higher. Here we examined whether facilitation of the invasive porcelain crab Petrolisthes elongatus by the ecosystem engineering serpulid tube worm Galeolaria caespitosa increased with wave exposure. Petrolisthes occurs beneath intertidal boulders which often have a high cover of Galeolaria on their underside. Surveys across nine sites demonstrated Petrolisthes abundance beneath boulders increased with wave exposure and Galeolaria cover, although only when the habitat matrix beneath boulders was rock or mixed rock and sand...
September 28, 2018: Marine Environmental Research
Laura Hyväri, Miina Ojansivu, Miia Juntunen, Kimmo Kartasalo, Susanna Miettinen, Sari Vanhatupa
Adipose tissue is an attractive stem cell source for soft and bone tissue engineering applications and stem cell therapies. The adipose-derived stromal/stem cells (ASCs) have a multilineage differentiation capacity that is regulated through extracellular signals. The cellular events related to cell adhesion and cytoskeleton have been suggested as central regulators of differentiation fate decision. However, the detailed knowledge of these molecular mechanisms in human ASCs remains limited. This study examined the significance of focal adhesion kinase (FAK), Rho-Rho-associated protein kinase (Rho-ROCK), and their downstream target extracellular signal-regulated kinase 1/2 (ERK1/2) on hASCs differentiation towards osteoblasts and adipocytes...
2018: Stem Cells International
Andrew R Davis, Mikel Becerro, Xavier Turon
The distribution of intertidal organisms can depend on processes operating early in their life history. The ascidian Pyura praeputialis, a mid- to low-intertidal habitat-forming ecosystem engineer, was strongly associated with specific types of habitat (biogenic vs. bare rock). We examined field patterns and performed laboratory and field experiments to assess the nature of this association. Recruits were frequently found on the tunics of conspecifics and clumps of turfing coralline algae. Larvae preferred these same habitats in a series of laboratory settlement assays...
September 22, 2018: Marine Environmental Research
Yingchao Wang, Fan Geng, Shengqi Yang, Hongwen Jing, Bo Meng
Groundwater inrush through fault fracture zones is caused by small particle migration from fractured rocks of the faults. To investigate particle migration with the water flow, a 3D model was established for the solid-water two-phase flow. First, the simulated crushed sandstone was represented by certain different-sized particles with a novel cohesive force. The discrete element method (DEM) was applied for particles considering the cohesive force, the collisions, the friction, and other conventional forces...
January 15, 2019: Journal of Hazardous Materials
Donglin Li, Pengzhen Cheng, Huijie Jiang, Tianqing Cao, Jimeng Wang, Yi Gao, Yangjing Lin, Chunmei Wang, Shuaishuai Zhang, Junqin Li, Bin Liu, Yue Song, Liu Yang, Guoxian Pei
The prevascularization of tissue-engineered bone grafts (TEBGs) has been shown to accelerate capillary vessel ingrowth in bone defect remodeling and to enhance new bone formation. However, the exact mechanisms behind this positive effect remain unknown. Here, we report that basic fibroblast growth factor (FGF2)-Ras homolog gene family member A (RhoA)/Rho-associated protein kinase (ROCK) signaling functions as a molecular switch to regulate the lineage fate of bone mesenchymal stem cells (BMSCs) and that prevascularization promotes the cell fate switch, which contributes to increased bone regeneration with the use of prevascularized TEBGs compared with control TEBGs...
September 20, 2018: Cell Death & Disease
Y Yang, S Bruns, S L S Stipp, H O Sørensen
The tendency for irreversible processes to generate entropy is the ultimate driving force for structure evolution in nature. In engineering, entropy production is often used as an indicator for loss of usable energy. In this study, we show that the analysis of entropy production patterns can provide insight into the diverse observations from experiments that investigate porous medium dissolution in imposed flow field. We first present a numerical scheme for the analysis of entropy production in dissolving porous media...
2018: PloS One
Grainne El Mountassir, James M Minto, Leon A van Paassen, Emmanuel Salifu, Rebecca J Lunn
Over the last 10-15 years, a new field of "biogeotechnics" has emerged as geotechnical engineers seek to find ground improvement technologies which have the potential to be lower carbon, more ecologically friendly, and more cost-effective than existing practices. This review summarizes the developments which have occurred in this new field, outlining in particular the microbial processes which have been shown to be most promising for altering the hydraulic and mechanical responses of soils and rocks...
2018: Advances in Applied Microbiology
Rebecca L Morris, Aline S Martinez, Louise B Firth, Ross A Coleman
The field of eco-engineering has burgeoned in recent years in response to the proliferation of artificial structures. Adding water-retaining features to seawalls has been successful in increasing biodiversity relative to the surrounding structure. Artificial rock pools may not, however, completely mimic natural rock pools. Here, we compared natural colonisation, through dispersal and recruitment, of intertidal mobile species to water-retaining flowerpots on seawalls with that into rock pools. This represents the more usual 'passive' approach to eco-engineering where features are built to enhance biodiversity and are allowed to colonise naturally, as opposed to seeding or transplanting organisms to features...
August 13, 2018: Marine Environmental Research
Camilla Campanati, Sam Dupont, Gray A Williams, Vengatesen Thiyagarajan
Anthropogenically-induced ocean acidification (OA) scenarios of decreased pH and altered carbonate chemistry are threatening the fitness of coastal species and hence near-shore ecosystems' biodiversity. Differential tolerances to OA between species at different trophic levels, for example, may alter species interactions and impact community stability. Here we evaluate the effect of OA on the larval stages of the rock oyster, Saccostrea cucullata, a dominant Indo-Pacific ecosystem engineer, and its key predator, the whelk, Reishia clavigera...
August 11, 2018: Marine Environmental Research
Biao Kong, Enyuan Wang, Zenghua Li
High temperature causes thermal damage to rock; the macrofracture and microfracture of rock can be produced under the action of temperature treatment. Under the influence of high temperature, the surrounding rock of deep underground engineering will suffer instability damage and cause serious harm to the people. In order to use the electromagnetic radiation (EMR) technology (a non-contact geophysical method) for evaluating the thermal stability of rock in underground thermal engineering applications, we established the EMR testing experimental system of rock under the action of a continuous heat source...
October 2018: Environmental Science and Pollution Research International
Kasparas Spokas, Catherine A Peters, Laura Pyrak-Nolte
Fractures present environmental risks for subsurface engineering activities, such as geologic storage of greenhouse gases, because of the possibility of unwanted upward fluid migration. The risks of fluid leakage may be exacerbated if fractures are subjected to physical and chemical perturbations that alter their geometry. This study investigated this by constructing a 2D fracture model to numerically simulate fluid flow, acid-driven reactions, and mechanical deformation. Three rock mineralogies were simulated: a limestone with 100% calcite, a limestone with 68% calcite, and a banded shale with 34% calcite...
September 4, 2018: Environmental Science & Technology
Changbin Tian, Zhengfang Wang, Qingmei Sui, Jing Wang, Yanan Dong, Yijia Li, Mingjuan Han, Lei Jia, Hanpeng Wang
The measurement accuracy of the intelligent flexible morphological sensor based on fiber Bragg grating (FBG) structure was limited in the application of geotechnical engineering and other fields. In order to improve the precision of intellisense for displacement, an FBG implantable flexible morphological sensor was designed in this study, and the classification morphological correction method based on conjugate gradient method and extreme learning machine (ELM) algorithm was proposed. This study utilized finite element simulations and experiments, in order to analyze the feasibility of the proposed method...
July 19, 2018: Sensors
Nilesh Kolhe, Smita Zinjarde, Celin Acharya
There is a strong interest in knowing how various microbial systems respond to the presence of uranium (U), largely in the context of bioremediation. There is no known biological role for uranium so far. Uranium is naturally present in rocks and minerals. The insoluble nature of the U(IV) minerals keeps uranium firmly bound in the earth's crust minimizing its bioavailability. However, anthropogenic nuclear reaction processes over the last few decades have resulted in introduction of uranium into the environment in soluble and toxic forms...
November 15, 2018: Biotechnology Advances
Swambabu Varanasi, Uthpala Garusinghe, George P Simon, Gil Garnier, Warren Batchelor
Inspired by the natural precipitation of minerals in soil and rocks, a novel, simple and industrially scalable in-situ precipitation process to produce low permeability porous composites is presented. This process relies on capillary flow in wettable porous composites to absorb and store liquid. In this process, a porous composite first absorbs a salt solution, after which the composite is dipped in a second salt solution. Salts are selected such as they react to form an insoluble precipitate. As big pores absorb more liquid than small pores, the precipitated particles are formed specifically for each pore...
July 16, 2018: Scientific Reports
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