Hepatocyte Aggregate Culture Technique for Bioreactors in Hybrid Liver Support Systems

1993 ◽  
Vol 16 (12) ◽  
pp. 843-846 ◽  
Author(s):  
J.C. Gerlach ◽  
K. Klöppel ◽  
C. MÜller ◽  
N. Schnoy ◽  
M.D. Smith ◽  
...  
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Support Systems ◽  
Three Dimensional ◽  
Culture Technique ◽  
Dimensional Structure ◽  
Cell Aggregates ◽  
Liver Support ◽  
Aggregate Culture

Utilizing a modified culture technique for hepatocytes, a high performance suspension culture is possible in which hepatocytes spontaneously form cell aggregates. The aggregates of 20-100 cells have been histologically confirmed to hold a three-dimensional structure, they show a long-term external metabolism and a survival time comparable with standard adhesion cultures. This technique has several advantages in the construction of large scale bioreactors for hybrid liver support systems.

Interpenetrating Gels as Conducting/Adhering Matrices Enabling High-Performance Silicon Anodes

2021 ◽  
Author(s):  
Tingting Xia ◽  
Chengfei Xu ◽  
Pengfei Dai ◽  
Xiaoyun Li ◽  
Riming Lin ◽  
...  
Keyword(s):  
Energy Storage ◽  
High Performance ◽  
Electrode Materials ◽  
Three Dimensional ◽  
Electrochemical Energy Storage ◽  
Active Materials ◽  
Silicon Anodes ◽  
Weak Binding ◽  
Binding Forces

Three-dimensional (3D) conductive polymers are promising conductive matrices for electrode materials toward electrochemical energy storage. However, their fragile nature and weak binding forces with active materials could not guarantee long-term...

scholarly journals High-resolution three-dimensional probes of biomaterials and their interfaces

2012 ◽  
Vol 370 (1963) ◽  
pp. 1337-1351 ◽  
Author(s):  
Kathryn Grandfield ◽  
Anders Palmquist ◽  
Håkan Engqvist
Keyword(s):  
High Resolution ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Controlled Drug Release ◽  
Biological Tissues ◽  
Dimensional Structure ◽  
Bone Interface ◽  
Biomaterial Interfaces ◽  
Titania Coating

Interfacial relationships between biomaterials and tissues strongly influence the success of implant materials and their long-term functionality. Owing to the inhomogeneity of biological tissues at an interface, in particular bone tissue, two-dimensional images often lack detail on the interfacial morphological complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar length scale. Electron tomography (ET) can meet these challenges by enabling high-resolution three-dimensional imaging of biomaterial interfaces. In this article, we review the fundamentals of ET and highlight its recent applications in probing the three-dimensional structure of bioceramics and their interfaces, with particular focus on the hydroxyapatite–bone interface, titanium dioxide–bone interface and a mesoporous titania coating for controlled drug release.

scholarly journals Biophysical and biochemical investigations of RNA catalysis in the hammerhead ribozyme

1999 ◽  
Vol 32 (3) ◽  
pp. 241-284 ◽  
Author(s):  
William G. Scott
Keyword(s):  
Metal Ions ◽  
Conformational Change ◽  
Large Scale ◽  
Enzyme Inhibitor ◽  
Hammerhead Ribozyme ◽  
Three Dimensional ◽  
Chemical Mechanism ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Hammerhead Rna

1. How do ribozymes work? 2412. The hammerhead RNA as a prototype ribozyme 2422.1 RNA enzymes 2422.2 Satellite self-cleaving RNAs 2422.3 Hammerhead RNAs and hammerhead ribozymes 2443. The chemical mechanism of hammerhead RNA self-cleavage 2463.1 Phosphodiester isomerization via an SN2(P) reaction 2473.2 The canonical role of divalent metal ions in the hammerhead ribozyme reaction 2513.3 The hammerhead ribozyme does not actually require metal ions for catalysis 2543.4 Hammerhead RNA enzyme kinetics 2574. Sequence requirements for hammerhead RNA self-cleavage 2604.1 The conserved core, mutagenesis and functional group modifications 2604.2 Ground-state vs. transition-state effects 2615. The three-dimensional structure of the hammerhead ribozyme 2625.1 Enzyme–inhibitor complexes 2625.2 Enzyme–substrate complex in the initial state 2645.3 Hammerhead ribozyme self-cleavage in the crystal 2645.4 The requirement for a conformational change 2655.5 Capture of conformational intermediates using crystallographic freeze-trapping 2665.6 The structure of a hammerhead ribozyme ‘early’ conformational intermediate 2675.7 The structure of a hammerhead ribozyme ‘later’ conformational intermediate 2685.8 Is the conformational change pH dependent? 2695.9 Isolating the structure of the cleavage product 2715.10 Evidence for and against additional large-scale conformation changes 2745.11 NMR spectroscopic studies of the hammerhead ribozyme 2786. Concluding remarks 2807. Acknowledgements 2818. References 2811. How do ribozymes work? 241The discovery that RNA can be an enzyme (Guerrier-Takada et al. 1983; Zaug & Cech, 1986) has created the fundamental question of how RNA enzymes work. Before this discovery, it was generally assumed that proteins were the only biopolymers that had sufficient complexity and chemical heterogeneity to catalyze biochemical reactions. Clearly, RNA can adopt sufficiently complex tertiary structures that make catalysis possible. How does the three- dimensional structure of an RNA endow it with catalytic activity? What structural and functional principles are unique to RNA enzymes (or ribozymes), and what principles are so fundamental that they are shared with protein enzymes?

scholarly journals Crystal structure of a tankyrase 1–telomere repeat factor 1 complex

2016 ◽  
Vol 72 (4) ◽  
pp. 320-327 ◽  
Author(s):  
Bo Li ◽  
Ruihong Qiao ◽  
Zhizhi Wang ◽  
Weihong Zhou ◽  
Xin Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Large Scale ◽  
Sparse Matrix ◽  
Critical Role ◽  
Three Dimensional ◽  
Mitotic Cell ◽  
Ankyrin Repeat ◽  
Dimensional Structure ◽  
Telomere Repeat ◽  
Tankyrase 1

Telomere repeat factor 1 (TRF1) is a subunit of shelterin (also known as the telosome) and plays a critical role in inhibiting telomere elongation by telomerase. Tankyrase 1 (TNKS1) is a poly(ADP-ribose) polymerase that regulates the activity of TRF1 through poly(ADP-ribosyl)ation (PARylation). PARylation of TRF1 by TNKS1 leads to the release of TRF1 from telomeres and allows telomerase to access telomeres. The interaction between TRF1 and TNKS1 is thus important for telomere stability and the mitotic cell cycle. Here, the crystal structure of a complex between the N-terminal acidic domain of TRF1 (residues 1–55) and a fragment of TNKS1 covering the second and third ankyrin-repeat clusters (ARC2-3) is presented at 2.2 Å resolution. The TNKS1–TRF1 complex crystals were optimized using an `oriented rescreening' strategy, in which the initial crystallization condition was used as a guide for a second round of large-scale sparse-matrix screening. This crystallographic and biochemical analysis provides a better understanding of the TRF1–TNKS1 interaction and the three-dimensional structure of the ankyrin-repeat domain of TNKS.

scholarly journals SVFX: a machine-learning framework to quantify the pathogenicity of structural variants

2019 ◽  
Author(s):  
Sushant Kumar ◽  
Arif Harmanci ◽  
Jagath Vytheeswaran ◽  
Mark B. Gerstein
Keyword(s):  
Machine Learning ◽  
Large Scale ◽  
Three Dimensional ◽  
Point Mutations ◽  
Dimensional Structure ◽  
Rapid Decline ◽  
Ras Signaling ◽  
Cancer Genes ◽  
Structural Variations ◽  
Pathogenic Variants

AbstractA rapid decline in sequencing cost has made large-scale genome sequencing studies feasible. One of the fundamental goals of these studies is to catalog all pathogenic variants. Numerous methods and tools have been developed to interpret point mutations and small insertions and deletions. However, there is a lack of approaches for identifying pathogenic genomic structural variations (SVs). That said, SVs are known to play a crucial role in many diseases by altering the sequence and three-dimensional structure of the genome. Previous studies have suggested a complex interplay of genomic and epigenomic features in the emergence and distribution of SVs. However, the exact mechanism of pathogenesis for SVs in different diseases is not straightforward to decipher. Thus, we built an agnostic machine-learning-based workflow, called SVFX, to assign a “pathogenicity score” to somatic and germline SVs in various diseases. In particular, we generated somatic and germline training models, which included genomic, epigenomic, and conservation-based features for SV call sets in diseased and healthy individuals. We then applied SVFX to SVs in six different cancer cohorts and a cardiovascular disease (CVD) cohort. Overall, SVFX achieved high accuracy in identifying pathogenic SVs. Moreover, we found that predicted pathogenic SVs in cancer cohorts were enriched among known cancer genes and many cancer-related pathways (including Wnt signaling, Ras signaling, DNA repair, and ubiquitin-mediated proteolysis). Finally, we note that SVFX is flexible and can be easily extended to identify pathogenic SVs in additional disease cohorts.

scholarly journals Prediction of Residual Stresses in a Multipass Pipe Weld by a Novel 3D Finite Element Approach

2018 ◽  
Author(s):  
Hui Huang ◽  
Jian Chen ◽  
Blair Carlson ◽  
Hui-Ping Wang ◽  
Paul Crooker ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
High Performance ◽  
Large Scale ◽  
Graphics Processing Unit ◽  
Computational Cost ◽  
Three Dimensional ◽  
Processing Unit ◽  
Girth Welds ◽  
Welding Processes

Due to enormous computation cost, current residual stress simulation of multipass girth welds are mostly performed using two-dimensional (2D) axisymmetric models. The 2D model can only provide limited estimation on the residual stresses by assuming its axisymmetric distribution. In this study, a highly efficient thermal-mechanical finite element code for three dimensional (3D) model has been developed based on high performance Graphics Processing Unit (GPU) computers. Our code is further accelerated by considering the unique physics associated with welding processes that are characterized by steep temperature gradient and a moving arc heat source. It is capable of modeling large-scale welding problems that cannot be easily handled by the existing commercial simulation tools. To demonstrate the accuracy and efficiency, our code was compared with a commercial software by simulating a 3D multi-pass girth weld model with over 1 million elements. Our code achieved comparable solution accuracy with respect to the commercial one but with over 100 times saving on computational cost. Moreover, the three-dimensional analysis demonstrated more realistic stress distribution that is not axisymmetric in hoop direction.

scholarly journals Bioinspired nano-ordered liquid membrane for precise molecular separation

2020 ◽  
Author(s):  
Haozhen Dou ◽  
Mi Xu ◽  
Baoyu Wang ◽  
Zhen Zhang ◽  
Guobin Wen ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Liquid Membrane ◽  
Three Dimensional ◽  
Cellular Membrane ◽  
Liquid Structure ◽  
Long Term Stability ◽  
Separation Membranes ◽  
Molecular Separation

Abstract Cellular membranes provide ideal archetypes for molecule or ion separations with sub-angstrom scale precision, which are featured with both extremely high permeability and selectivity due to the well-defined membrane protein channels. However, the development of bioinspired membranes with artificial channels for sub-angstrom scale ethylene/ethane (0.416 nm / 0.443 nm) separation remains an uncharted territory and a significant challenge. Herein, a bioinspired nano-ordered liquid membrane is constructed by a facile ion/molecule self-assembly strategy for highly efficient ethylene/ethane separation, which mimics the structure of cellular membrane elegantly and possesses plenty of three-dimensional (3D) nanochannels. The elaborate regulation of non-covalent interactions by optimizing the ion/molecule compositions within membrane confers the nano-ordered liquid structure with interpenetrating and bi-continuous apolar domains and polar domains, which results in the formation of regular carrier wires and enormous 3D interconnected ethylene transport nanochannels. By virtue of these 3D nanochannels, the bioinspired nano-ordered liquid membrane manifests simultaneously super-high selectivity, excellent permeance and long-term stability, which exceeds previously reported ethylene/ethane separation membranes. This methodology in this work for construction of bioinspired membrane with tunable 3D nanochannels through ion/molecule self-assembly will enlighten the design and development of high-performance separation membranes for angstrom/sub-angstrom scale ion or molecule separations.

scholarly journals An Initiation Process of Tropical Depression-type Disturbances under the Influence of Upper-level Troughs

2021 ◽  
Author(s):  
Yuya Hamaguchi ◽  
Yukari N. Takayabu
Keyword(s):  
Large Scale ◽  
Convective Available Potential Energy ◽  
Three Dimensional ◽  
Lower Troposphere ◽  
Dimensional Structure ◽  
Convective Heating ◽  
Upper Troposphere ◽  
Tropical Depression ◽  
Upper Level ◽  
Extratropical Forcing

AbstractIn this study, the statistical relationship between tropical upper-tropospheric troughs (TUTTs) and the initiation of summertime tropical-depression type disturbances (TDDs) over the western and central North Pacific is investigated. By applying a spatiotemporal filter to the 34-year record of brightness temperature and using JRA-55 reanalysis products, TDD-event initiations are detected and classified as trough-related (TR) or non-trough-related (non-TR). The conventional understanding is that TDDs originate primarily in the lower-troposphere; our results refine this view by revealing that approximately 30% of TDDs in the 10°N-20°N latitude ranges are generated under the influence of TUTTs. Lead-lag composite analysis of both TR- and non-TR-TDDs clarifies that TR-TDDs occur under relatively dry and less convergent large-scale conditions in the lower-troposphere. This result suggests that TR-TDDs can form in a relatively unfavorable low-level environment. The three-dimensional structure of the wave activity flux reveals southward and downward propagation of wave energy in the upper troposphere that converges at the mid-troposphere around the region where TR-TDDs occur, suggesting the existence of extratropical forcing. Further, the role of dynamic forcing associated with the TUTT on the TR-TDD-initiation is analyzed using the quasi-geostrophic omega equation. The result reveals that moistening in the mid-to-upper troposphere takes place in association with the sustained dynamical ascent at the southeast side of the TUTT, which precedes the occurrence of deep convective heating. Along with a higher convective available potential energy due to the destabilizing effect of TUTTs, the moistening in the mid-to-upper troposphere also helps to prepare the environment favorable to TDDs initiation.

Three-Dimensional MoS2/Graphene Hybrid Aerogel as Free-Standing, High-Performance Electrode for Supercapacitor

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050062
Author(s):  
Zhaolei Meng ◽  
Xiaojian He ◽  
Song Han ◽  
Zijian Hu
Keyword(s):  
Porous Structure ◽  
Surface Area ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Hydrothermal Process ◽  
Three Dimensional ◽  
Rate Capability ◽  
Free Standing ◽  
Hybrid Aerogel

Carbon materials are generally employed as supercapacitor electrodes due to their low- cost, high-chemical stability and environmental friendliness. However, the design of carbon structures with large surface area and controllable porous structure remains a daunt challenge. In this work, a three-dimensional (3D) hybrid aerogel with different contents of MoS2 nanosheets in 3D graphene aerogel (MoS2-GA) was synthesized through a facial hydrothermal process. The influences of MoS2 content on microstructure and subsequently on electrochemical properties of MoS2-GA are systematically investigated and an optimized mass ratio with MoS2: GA of 1:2 is chosen to achieve high mechanical robustness and outstanding electrochemical performance in the hybrid structure. Due to the large specific surface area, porous structure and continuous charge transfer network, such MoS2-GA electrodes exhibit high specific capacitance, good rate capability and excellent cyclic stability, showing great potential in large-scale and low-cost fabrication of high-performance supercapacitors.

scholarly journals Superior Pseudocapacitive Storage of a Novel Ni3Si2/NiOOH/Graphene Nanostructure for an All-Solid-State Supercapacitor

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jing Ning ◽  
Maoyang Xia ◽  
Dong Wang ◽  
Xin Feng ◽  
Hong Zhou ◽  
...  
Keyword(s):  
Solid State ◽  
High Performance ◽  
Large Scale ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Specific Area ◽  
High Energy ◽  
Scale Production ◽  
Free Standing

Abstract Recent developments in the synthesis of graphene-based structures focus on continuous improvement of porous nanostructures, doping of thin films, and mechanisms for the construction of three-dimensional architectures. Herein, we synthesize creeper-like Ni3Si2/NiOOH/graphene nanostructures via low-pressure all-solid melting-reconstruction chemical vapor deposition. In a carbon-rich atmosphere, high-energy atoms bombard the Ni and Si surface, and reduce the free energy in the thermodynamic equilibrium of solid Ni–Si particles, considerably catalyzing the growth of Ni–Si nanocrystals. By controlling the carbon source content, a Ni3Si2 single crystal with high crystallinity and good homogeneity is stably synthesized. Electrochemical measurements indicate that the nanostructures exhibit an ultrahigh specific capacity of 835.3 C g−1 (1193.28 F g−1) at 1 A g−1; when integrated as an all-solid-state supercapacitor, it provides a remarkable energy density as high as 25.9 Wh kg−1 at 750 W kg−1, which can be attributed to the free-standing Ni3Si2/graphene skeleton providing a large specific area and NiOOH inhibits insulation on the electrode surface in an alkaline solution, thereby accelerating the electron exchange rate. The growth of the high-performance composite nanostructure is simple and controllable, enabling the large-scale production and application of microenergy storage devices.

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