High-Speed Broadband Real-Time Monitoring of Cell Viscoelasticity Reveals Oscillatory Myosin Activity

2016 ◽  
Author(s):  
Bo Yan ◽  
Juan Ren ◽  
Xi Zheng ◽  
Yue Liu ◽  
Qingze Zou
Keyword(s):  
Elastic Modulus ◽  
High Speed ◽  
Biological Species ◽  
Live Cells ◽  
Viscoelastic Modulus ◽  
Acceleration Force ◽  
Probe Microscope ◽  
Second Period ◽  
Large Frequency ◽  
Cellular Measurements

This article presents the investigation of the dynamic behavior of the cytoskeleton of live human cells, enabled by a recently-developed control-based approach on scanning probe microscope (SPM). Mechanical behaviors of live cells play an important role in various cell physiological and pathological activities, and have been studied via various techniques and approaches. Studies of evolutions of mechanical properties of live cell, however, are still rather limited and scarce, due to the limitations of current instruments including SPM for single cellular measurements. Particularly, currently nanomechanical measurements using SPM is too slow to excite the mechanical behavior and then measure the corresponding response of life biological species over a large frequency range (broadband). Moreover, large uncertainty is induced in the in-liquid nanomechanical measurement using SPM, as in the indentation quantification, the effects of the acceleration force from the cantilever motion and the hydrodynamic force are not accounted for. The main contribution of this article is the use of a control-based nanomechanical protocol to interrogate the viscoelasticity oscillation of live human prostate cancer cell (PC-3 cells) and its dependence on myosin activities. The experiment results show that as the oscillation of static elastic modulus reported earlier in the literature, the oscillation of dynamic viscoelastic modulus measured is also periodic with a 200-second period. Moreover, as the elastic modulus oscillation, both the amplitude and the period of the viscoelasticity oscillation also strongly depend on the myosin activities, and closely regulated by the calcium density of the cytoskeleton.

Быстродействующая атомно-силовая и сканирующая капиллярная микроскопия в решении задач материаловедения, биологии и медицины

2020 ◽  
Vol 13 (3-4) ◽  
pp. 222-228
Author(s):  
И.В. Яминский ◽  
А.И. Ахметова
Keyword(s):  
Antibiotic Resistance ◽  
Early Detection ◽  
Biomedical Research ◽  
Drug Screening ◽  
Targeted Delivery ◽  
High Speed ◽  
Scanning Probe ◽  
Biological Processes ◽  
Atomic Force ◽  
Probe Microscope

Разработка высокоэффективных режимов быстродействующего сканирующего зондового микроскопа, в первую очередь атомно-силовой и сканирующей капиллярной микроскопии, представляет особый интерес для успешного проведения биомедицинских исследований: изучения биологических процессов и морфологии биополимеров, определения антибио­тикорезистентности бактерий, адресной доставки биомакромолекул, скринингу лекарств, раннему обнаружению биологических агентов (вирусов и бактерий) и др. The development of highly efficient modes of a high-speed scanning probe microscope, primarily atomic force and scanning capillary microscopy, is of particular interest for successful biomedical research: studying biological processes and the morphology of biopolymers, determining antibiotic resistance of bacteria, targeted delivery of biomacromolecules, drug screening, early detection agents (viruses and bacteria), etc.

scholarly journals Dynamic Triaxial Test and Microscopic Study of Solidified Muddy Soil With Different Mixing Ratios and Curing Ages

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhou Chen ◽  
Haocheng Xu ◽  
Mayao Cheng ◽  
Hanwen Lu ◽  
Zhijian Wang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Triaxial Test ◽  
High Speed ◽  
Dynamic Strength ◽  
Dynamic Strain ◽  
Hydration Reaction ◽  
Curing Agent ◽  
Mixture Ratio ◽  
Dynamic Triaxial Test ◽  
Curing Age

Aiming to explore the optimal mixture ratio and curing age of solidified muddy soil under dynamic load, the paper intends to investigate whether the solidified muddy soil can be used as filling of high-speed railway subgrade. Based on the dynamic triaxial test, the investigation measured the dynamic strain and dynamic elastic modulus of solidified muddy soil under different mix ratios and curing ages, and also observed the microscopic morphology of solidified muddy soil samples by using scanning electron microscope. The results show that the addition of cement and curing agent significantly increases the dynamic strength and elastic modulus of muddy soil, which effectively improve the dynamic characteristics of muddy soil. The curing effect of the curing agent is more obvious with the increase of the dosage of cement and curing agent under different mix ratio. The content of curing agent plays a leading role in the hydration reaction between cement, curing agent and soil particles. Additionally, in case of the same test conditions, when the ratio of cement mass to dry silt mass is 1:20, the ratio of diluent volume to dry silt mass is 1:20, with 28 days of curing age, its curing effect will reach the best.

scholarly journals Achieving High-Speed Retraction in a Stretchable Hydrogel

2020 ◽  
Author(s):  
Rosa Maria Badani Prado ◽  
Satish Mishra ◽  
Buckston Morgan ◽  
Rangana Wijayapala ◽  
Seyed Meysam Hashemnejad ◽  
...  
Keyword(s):  
High Speed ◽  
Biological Tissues ◽  
Biological Species ◽  
Vital Role ◽  
Polypropylene Glycol ◽  
Glycol Diacrylate ◽  
Mantis Shrimp ◽  
Power Amplification ◽  
Short Period ◽  
Very High

Many biological species apply the power amplification mechanism for locomotion, feeding, and protection. In power amplification, a biological system rapidly releases stored-energy by achieving a very high velocity over a short period of time, resulting in high power output. Such power amplification allows insects such as locust to jump and Mantis shrimp to kill prey by its appendage strike. Biological elastomeric polymers such as resilin play a vital role in the power amplification process because of their high stretchability and resilience. In synthetic materials, although<br>crosslinked rubbers display high stretchability and resilience, such is difficult to achieve in the water-containing systems such as in hydrogels, commonly considered materials for mimicking biological tissues. Here, we have used a simple free-radical polymerization of acrylic acid (AAc), methacrylamide (MAAm), and polypropylene glycol diacrylate (PPGDA) to obtain hydrogels. In these gels, the polymerized AAc and MAAm act as hydrophilic blocks and PPG as hydrophobic, and the gel structure resemble that of resilin consisting of hydrophilic and hydrophobic components. The bioinspired gels display very high stretchability, as high as eight times the original length, and greater than 90% resilience. In addition, the gel samples can reach a retraction velocity of 16 m/s with an acceleration of 4X10^3 m/s2. These values are similar or better than those observed in water containing biological systems, such as appendage strikes in Mantis shrimp, etc. To the best of our knowledge, such performance has not been reported in the<br>literature for any water containing networks.

Fatigue Behavior of Cement Asphalt Emulsion Mortar

2016 ◽  
Vol 847 ◽  
pp. 25-30 ◽  
Author(s):  
Dong Mei Tian ◽  
Jian Yin
Keyword(s):  
Elastic Modulus ◽  
Yield Strength ◽  
High Speed ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Permanent Deformation ◽  
Negative Temperature ◽  
Fatigue Tests ◽  
Asphalt Emulsion ◽  
Slab Track

As one of the key components of non-ballast slab track in high speed railway, cement asphalt emulsion mortar (CAM) has low compressive strength and low elastic modulus. This makes CAM possible to be served as supporting, height-adjusting, vibration-dissipating and deformation-fitting sandwich-layer between pre-stress slab and concrete roadbed. To study the fatigue behavior of the CAM, fatigue tests were conducted at room temperature and negative temperature, respectively. The permanent strain, elastic modulus and yield strength of fatigue-tested specimens were compared to the reference one. The results showed that the small permanent deformation lead to very little displacement differences among the slab track system. Secondly, the elastic modulus and yield strength of fatigue test specimens were both higher than that of reference one. Because the fatigue process might strengthen the CAM by compacting micro-cracks. Additionally, arising from the temperature sensitivity of asphalt, viscosity behavior of asphalt mortar at room temperature is changed to brittleness behavior at negative temperature.

Strains in Aluminum-Adhesive-Ceramic Trilayers

1990 ◽  
Vol 112 (4) ◽  
pp. 288-302 ◽  
Author(s):  
P. M. Hall ◽  
F. L. Howland ◽  
Y. S. Kim ◽  
L. H. Herring
Keyword(s):  
Elastic Modulus ◽  
High Speed ◽  
Theoretical Study ◽  
Alumina Ceramic ◽  
Strain Gages ◽  
Wire Bonds ◽  
Large Expansion ◽  
Trilayer Structure ◽  
Almost All ◽  
Increasing Temperature

In many of today’s high speed, high density circuits, there is a need to remove large amounts of heat. To facilitate this removal of heat, it is common to adhere a sheet of a high thermal conductivity material (such as aluminum or copper) to the substrate (which may be alumina ceramic). This can result in large expansion mismatches which cause stresses and bowing, with the possibility of delamination, cracking, stressing solder joints, loss of hermeticity, or shorting of a metal lid to wire bonds inside a cavity. One approach to this problem is to use a compliant adhesive to decouple the materials. The present paper is an experimental and theoretical study of the strains as a function of temperature from −40° C to 140° C in a trilayer structure of 0.030 in. or 0.76 mm thick aluminum, 0.006 in. or 0.15 mm thick adhesive, and 0.021 in. or 0.5 mm thick low-temperature cofired (glassy) ceramic. The strains are analyzed using E. Suhir’s theory, and they are measured using strain gages for three adhesives: an epoxy, a fabric-reinforced epoxy, and a silcone elastopolymer. If the adhesive has an elastic modulus below 10 psi or 70 kPa, theory predicts almost complete de-coupling. Between 100 and 105 psi or 700 kPa and 700 MPa, there is partial decoupling, depending on the in-plane dimensions. Above 10,000 psi or 700 MPa, the decoupling is negligible, and the same bowing results for any elastic modulus between 10,000 and 1,000,000 psi or 70 MPa and 7 GPa. For temperatures below 80° C, only the elastomer has enough compliance to provide any de-coupling. Above 80° C, the elastomer de-couples the most, and the unreinforced epoxy the least. Almost all of the observed effects are understandable in terms of the Suhir theory, along with the fact that the elastic modulus of the epoxy materials decreases with increasing temperature. In particular, when there is some decoupling of the materials, the amount of decoupling depends on the in-plane dimensions of the sample.

scholarly journals Effect of Heating Rate on the Dynamic Compressive Properties of Granite

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ronghua Shu ◽  
Tubing Yin ◽  
Xibing Li
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Heating Rate ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Quadratic Function ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Compressive Properties ◽  
Dynamic Compressive Strength

Variation in the heating rate due to different geothermal gradients is a cause of much concern in underground rock engineering such as deep sea and underground tunnels, nuclear waste disposal, and deep mining. By using a split Hopkinson pressure bar (SHPB) and variable-speed heating furnace, the dynamic compressive properties of granite were obtained after treatments at different heating rates and temperatures; these properties mainly included the dynamic compressive strength, peak strain, and dynamic elastic modulus. The mechanism of heating rate action on the granite was simultaneously analyzed, and the macroscopic physical properties were discussed. The microscopic morphological features were obtained by scanning electron microscopy (SEM), and the crack propagation was determined by high-speed video camera. The experimental results show that the dynamic compressive strength and elastic modulus both show an obvious trend of a decrease with the increasing heating rate and temperature; the opposite phenomenon is observed for the peak strain. The relationships among the dynamic compressive properties and temperature could be described by the quadratic function. The ductility of granite is enhanced, and the number and size of cracks increase gradually when the heating rate and temperature increase. The microstructure of rock is weakened by the increased thermal stress, which finally affects the dynamic compressive properties of rock.

Resonance compensating chirp mode for mapping the rheology of live cells by high-speed atomic force microscopy

2018 ◽  
Vol 113 (9) ◽  
pp. 093701 ◽  
Author(s):  
Marc Schächtele ◽  
Erik Hänel ◽  
Tilman E. Schäffer
Keyword(s):  
Atomic Force Microscopy ◽  
High Speed ◽  
Live Cells ◽  
Force Microscopy ◽  
Atomic Force
Sign in / Sign up

Export Citation Format

Share Document