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arXiv 2020年

作者： Liu, Changjiang Elvati, Paolo Violi, Angela Biophysics Program University of Michigan Ann ArborMI48109-2125 United States Department of Mechanical Engineering University of Michigan Ann ArborMI48109-2125 United States Department of Chemical Engineering University of Michigan Ann ArborMI48109-2125 United States

To shorten the time required to find effective new drugs, like antivirals, a key parameter to consider is membrane permeability, as a compound intended for an intracellular target with poor permeability will have low efficacy. Here, we present a computational model that considers both drug characteristics and membrane properties for the rapid assessment of drugs permeability through the coronavirus envelope and various cellular membranes. We analyze 79 drugs that are considered as potential candidates for the treatment of SARS-CoV-2 and determine their time of permeation in different organelle membranes grouped by viral baits and mammalian processes. The computational results are correlated with experimental data, present in the literature, on bioavailability of the drugs, showing a negative correlation between fast permeation and most promising drugs. This model represents an important tool capable of evaluating how permeability affects the ability of compounds to reach both intended and unintended intracellular targets in an accurate and rapid way. The method is general and flexible and can be employed for a variety of molecules, from small drugs to nanoparticles, as well to a variety of biological membranes. Copyright © 2020, The Authors. All rights reserved.

关键词： Molecular dynamics

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Origami lattices and folding-induced lattice transformations

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Physical Review Research 2019年第2期1卷 023010-023010页

作者： Hongbin Fang Suyi Li Manoj Thota K. W. Wang Institute of AI and Robotics Fudan University Shanghai 200433 China Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109 USA Department of Mechanical Engineering Clemson University Clemson South Carolina 29634 USA

Lattices and their underlying symmetries play a central role in determining the physical properties and applications of many natural and engineered materials. This research offers a comprehensive solution to a long-standing challenge regarding the lattice-based materials: how to systematically construct a lattice and transform it among different symmetric configurations in a predictable, scalable, and reversible way. By bridging the lattice geometry and rigid-folding kinematics of a group of origamis consisting of generic degree-4 vertices, we successfully construct all types of two- and three-dimensional Bravais lattices, and demonstrate that they can undergo all diffusionless phase transformations via rigid folding (i.e., dilation, extension, contraction, shear, and shuffle). Such folding-induced lattice transformations can trigger fundamental lattice-symmetry switches, which can either maintain or reconstruct the nearest-neighbor relationships according to a continuous symmetry measure. This study can foster the next generation of transformable lattice structures and materials with on-demand property tuning capabilities.

关键词： Microstructure Origami & Kirigami Phase transitions Metamaterials Symmetries Geometry Lattice models in condensed matter

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The Effects of Rain Intensity and Water Elevation with Energy Productivity of Kracak Hydro Power Plant, Bogor Regency – West Java

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Journal of Physics: Conference Series 2021年第1期2111卷

作者： I A Rahardjo Suyitno M Subekti W Gunawan R P Wijayanto I Mahir Sakirah Electrical Engineering Education Program Universitas Negeri Jakarta Rawamangun Indonesia BPPT Indonesia Mechanical Engineering Department Universitas Negeri Jakarta Rawamangun Indonesia Electrical Engineering Program Taruna Bangsa of Vocational High School Bekasi Indonesia

This paper was aimed to know the effects of rain intensity and water elevation with energy productivity of Kracak Hydro Power Plant, Bogor Regency – West Java. The method used multiple regression analysis with a quantitative approach to describe the effects of rain intensity and water elevation with energy productivity of Kracak Hydro Power Plant. Based on the data, the highest rain intensity was in February of 13,35 mm with water elevation of 346,09 cm and produced electrical energy of 198.296 kWh. The lowest rain intensity was in July of 0,86 mm with water elevation of 194,02 cm and produced electrical energy of 49.772 kWh. The average rain intensity was 8,9 mm with water elevation of 324,12 cm and produced electrical energy of 156.010 kWh. The results of testing the effect of rain intensity with energy productivity at the Kracak hydropower plant resulted in a significance value of 0.002 (p <0.05) and a t value of 4.306. This value indicates that the significance value is below 0.05 and has a positive coefficient direction. It means that rain intensity has a significant positive effect with energy productivity at the Kracak hydropower plant. And the results of testing the effect of water elevation with energy productivity at the Kracak hydropower plant resulted in a significance value of 0.003 (p <0.05) and a t value of 3.864. This value indicates that the significance value is below 0.05 and has a positive coefficient direction. It means that water elevation has a significant positive effect with energy productivity at the Kracak hydropower plant. The conclusion on this research is the rain intensity and water elevation have effects with energy productivity of Kracak Hydro Power Plant.

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Ultra-Cold Cryogenic TEM Sample Holder with Liquid Helium and High Stability

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Microscopy and Microanalysis 2024年第SUPPLEMENT_1期30卷

作者： Gates, Maya Rennich, Emily Sung, Suk Hyun Agarwal, Nishkarsh Kerns, Robert Hovden, Robert Baggari, Ismail El Department of Mechanical Engineerin University of Michigan Ann Arbor MI USA Rowland Institute at Harvard University Cambridge MA USA Department of Materials Science & Engineering University of Michigan Ann Arbor MI USA Michigan Center for Materials Characterization University of Michigan Ann Arbor MI USA Applied Physics Program University of Michigan Ann Arbor MI USA

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Activated carbon characteristics of tabah bamboo that physically activated under different activation time 1

Activated carbon characteristics of tabah bamboo that physic...

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1st International Conference on Design, Energy, Materials and Manufacture, ICDEMM 2018

作者： Negara, D.N.K.P. Nindhia, T.G.T. Surata, I.W. Sucipta, M. Hidajat, F. Doctoral Study Program of Engineering Science Faculty of Engineering Udayana University Kampus Sudirman Denpasar-Bali Indonesia Mechanical Engineering Department Udayana University Street of Bukit Jimbaran Bali Badung Indonesia PPPTMGB Lemigas Jl. Ciledug Raya Kav. 109 Jakarta Selatan12230 Indonesia

Activated carbon is a versatile porous material that widely applied to purify, deodorize, decolorize, remove or reduce some gases harmful constituents and storage of gas. For different application different characteristics of activated carbon is required. This paper concerns to find out the characteristics of activated carbons derived from tabah bamboo (Gigantochloc nigrociliata) that physically activated with different activation holding time. Prepared tabah bamboo was carbonized by heating up to the temperature of 800 °C for two hours. The char produced was powdered and then activated physically by heating up to 800 °C, soaked at that temperature during each 1, 1.5 and 2 hours under 100 mL/min N2 flow. Activated carbons manufactured were characterized by proximate and ultimate analyses and SEM observation. The results show that the highest fix carbon (82.52%) and lowest ash (5.91 %) was obtained at 1 hour soaking time with moisture and volatile contents were 3.56% and 8.00 % respectively;the highest carbon (C) content of 84.16 % was yielded at soaked time of 1.5 hours;SEM observation shows that there were significant differences of morphology structure between raw material and activated carbons for all of the soaking time variations. The pores structures have been formed in the activated carbons produced. © Published under licence by IOP Publishing Ltd.

关键词： Activated carbon

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Modeling liquid water by climbing up Jacob’s ladder in density functional theory facilitated by using deep neural network potentials

arXiv

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arXiv 2021年

作者： Zhang, Chunyi Tang, Fujie Chen, Mohan Zhang, Linfeng Qiu, Diana Y. Perdew, John P. Klein, Michael L. Wu, Xifan Department of Physics Temple University PhiladelphiaPA19122 United States HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing100871 China Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Department of Chemistry Temple University PhiladelphiaPA19122 United States Institute for Computational Molecular Science Temple University PhiladelphiaPA19122 United States

Within the framework of Kohn-Sham density functional theory (DFT), the ability to provide good predictions of water properties by employing a strongly constrained and appropriately normed (SCAN) functional has been extensively demonstrated in recent years. Here, we further advance the modeling of water by building a more accurate model on the fourth rung of Jacob’s ladder with the hybrid functional, SCAN0. In particular, we carry out both classical and Feynman path-integral molecular dynamics calculations of water with the SCAN0 functional and the isobaric-isothermal ensemble. In order to generate the equilibrated structure of water, a deep neural network potential is trained from the atomic potential energy surface based on ab initio data obtained from SCAN0 DFT calculations. For the electronic properties of water, a separate deep neural network potential is trained using the Deep Wannier method based on the maximally localized Wannier functions of the equilibrated trajectory at the SCAN0 level. The structural, dynamic, and electric properties of water were analyzed. The hydrogen-bond structures, density, infrared spectra, diffusion coefficients, and dielectric constants of water, in the electronic ground state, are computed using a large simulation box and long simulation time. For the properties involving electronic excitations, we apply the GW approximation within many-body perturbation theory to calculate the quasiparticle density of states and bandgap of water. Compared to the SCAN functional, mixing exact exchange mitigates the self-interaction error in the meta-generalized-gradient approximation and further softens liquid water towards the experimental direction. For most of the water properties, the SCAN0 functional shows a systematic improvement over the SCAN functional. © 2021, CC BY.

关键词： Deep neural networks

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Influence of third element of TiNi alloy on tribological behavior in dry and wet conditions for orthodontic applications 9th

Influence of third element of TiNi alloy on tribological beh...

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9th International Conference on Advanced Materials Research, ICAMR 2019

作者： Phukaoluan, A. Khantachawana, A. Kaewtatip, P. Dechkunakorn, S. Program in Energy and Environmental Management Faculty of Technology Siam Technology College Bangkok10600 Thailand Department of Mechanical Engineering Faculty of Engineering King Mongkut's University of Technology Thonburi Bangkok10140 Thailand Department of Orthodontics Faculty of Dentistry Mahidol University Bangkok10400 Thailand

ISBN: (纸本)9783035714845

The tribological behavior of Ti49.4Ni50.6, Ti49Ni46Cu5 and Ti50Ni47Co3 (at%) alloy in dry and wet conditions was studied. The alloy was prepared in a Vacuum Arc Re-melting (VAR), homogenized at 800oC for 3600 s and quenched in water. The phase transformation temperatures were measured by differential scanning calorimetry. Before a tribology test, it is necessary to determine surface roughness, because high surface roughness affects friction. The hardness behavior, based on the load over residual indent area, was determined by a Vickers hardness tester. The sliding friction tests were performed using a ball-on-disk tribometer in dry condition at room temperature and wet condition in artificial saliva (pH 5.35) at 37oC (Oral temperature). The results showed that transformation temperature (Af) lowered oral temperature (37oC), this was mainly attributed to the superelastic properties that can be taken into orthodontic applications. The studies showed significant influences in dry condition of coefficient of friction. Caused by the force between the ball and the disk, contact pressure of surface area effect in wear occurred. The debris could not be removed from the surface area tested. TiNiCu and TiNiCo generated significantly lower average coefficient of friction when tested under dry condition, which may have been due to the addition of Cu and Co. Wet condition decreased coefficient of friction more than dry condition, owing to the lubricating effects of artificial saliva. © 2019 Trans Tech Publications Ltd, Switzerland.

关键词： Surface roughness

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Global health front-end medical device design: The use of prototypes to engage stakeholders

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Development engineering 2020年 5卷

作者： Coulentianos, Marianna J. Rodriguez-Calero, Ilka Daly, Shanna R. Sienko, Kathleen H. Design Science Program University of Michigan 1075 Beal Ave Ann ArborMI48109 United States Department of Mechanical Engineering University of Michigan 2350 Hayward Street Ann ArborMI48109 United States

Availability, accessibility, affordability, and appropriateness are among several factors that significantly affect the adoption and diffusion of medical devices in low- and middle-income countries. Design processes that promote early and frequent engagement with stakeholders may increase the impact of medical devices aimed at addressing global health challenges by improving the uptake and sustained use of such devices. Prototypes are tools that can be leveraged to engage stakeholders during front-end design to define the problem, elicit requirements, and obtain feedback on early design concepts. Given the lack of literature that examines the practices for stakeholder engagement with prototypes during front-end design, this study was guided by the following research question: How do global health design practitioners approach stakeholder engagement with prototypes during front-end medical device design? Eleven design practitioners from industry were interviewed;transcripts were analyzed using thematic analysis to uncover prototyping behaviors. Transcript level counts of stakeholder groups, prototype forms, and strategies leveraged during stakeholder engagement with prototypes are reported. Based on the analysis of stakeholders, prototypes, and strategies, engagement events that reflect how the global health setting influenced decisions of stakeholder, prototype, and strategy are presented. Participants described challenges associated with: cross-cultural and remote design;the elicitation of contextual requirements;and limited access to resources. Participants devised approaches to overcome these challenges such as: engaging a wide range of stakeholders including proxy users and government stakeholders;developing long-term relationships with community partners;leveraging communication technologies;engaging stakeholders in the real use environment with physical prototypes;using prototypes to bridge the language barrier;‘polishing’ prototypes;and inviting stakeholders

关键词： Availability

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Stereolithographic (SLA) 3D Printing of Microfluidic Flow Cells to Encapsulate EM Grids Used to Culture Cells for Correlative Imaging Studies

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Microscopy and Microanalysis 2024年第SUPPLEMENT_1期30卷

作者： Rienstra, Nicholas M Sanchez, Juan C Garvis, Steve Fischer, Heather Wright, Elizabeth R Department of Biochemistry University of Wisconsin-Madison Madison WI USA Department of Mechanical Engineering University of Wisconsin-Madison Madison WI USA Biophysics Graduate Program University of Wisconsin-Madison Madison WI USA Cryo-Electron Microscopy Research Center University of Wisconsin Madison WI USA Mortgridge Institute for Research University of Wisconsin-Madison Madison WI USA

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Spotlight-based 3D instrument guidance for retinal surgery

arXiv

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arXiv 2020年

作者： Zhou, Mingchuan Wu, Jiahao Ebrahimi, Ali Patel, Niravkumar He, Changyan Gehlbach, Peter Taylor, Russell H. Knoll, Alois Nasseri, M. Ali Iordachita, Iulian Department of Mechanical Engineering and Laboratoryfor Computational Sensing and Robotics The Johns Hopkins University BaltimoreMD21218 United States Chair of Robotics Artificial Intelligence and Real-time Systems Technische Universität München München85748 Germany T Stone Robotics Institute The Department of Mechanical and Automation Engineering The Chinese University of HongKong Hong Kong The Wilmer Eye Institute Johns Hopkins Hospital BaltimoreMD21287 United States Augenklinik und Poliklinik Klinikum rechts der Isar der Technische Universität München München81675 Germany

Retinal surgery is a complex activity that can be challenging for a surgeon to perform effectively and safely. Image guided robot-assisted surgery is one of the promising solutions that bring significant surgical enhancement in treatment outcome and reduce the physical limitations of human surgeons. In this paper, we demonstrate a novel method for 3D guidance of the instrument based on the projection of spotlight in the single microscope images. The spotlight projection mechanism is firstly analyzed and modeled with a projection on both a plane and a sphere surface. To test the feasibility of the proposed method, a light fiber is integrated into the instrument which is driven by the Steady-Hand Eye Robot (SHER). The spot of light is segmented and tracked on a phantom retina using the proposed algorithm. The static calibration and dynamic test results both show that the proposed method can easily archive 0.5 mm of tip-to-surface distance which is within the clinically acceptable accuracy for intraocular visual guidance. © 2020, CC BY.

关键词： Ophthalmology

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