Search query: Mechanism of thermal stress

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abstract: Abstract We report the failure of copper through silicon via (TSV) under biased thermal stress. The time dependent dielectric breakdown (TDDB) of the oxide liner in the TSV was measured to detect the migration of copper from TSV to silicon. The breakdown of the oxide liner occurred by thermal cracking followed by fast drift of copper ions through the crack. For the TSV structure, there were an initial decrease in the leakage current and then the breakdown of oxide, which is different from the 3 stage TDDB behavior observed in the planar metal oxide semiconductor (MOS) structure. Micro cracks in the oxide liner at the top corner of TSV were observed after TDDB measurement, and the thermal cracking of the oxide was caused by the expansion of copper TSV at test condition. Finite element analysis showed the tensile stress of 670 MPa concentrated at the top corner of the TSV. The mechanism of TDDB in both TSV and planar MOS structures were also described comparatively.
author_names: Seung-ho Seo

Joo-Sun Hwang

Jun-Mo Yang

Wook-Jung Hwang

Jun Yeob Song

Won-Jun Lee
title: Failure mechanism of copper through silicon vias under biased thermal stress
year: 2012

abstract: To gain a deep understanding of yeast cell response to heat stress, multiple laboratory strains have been intensively studied via genome wide expression analysis for the mechanistic dissection of classical heat shock response (HSR) However, robust industrial strains of Saccharomyces cerevisiae have hardly been explored in global analysis for elucidation of the mechanism of thermotolerant response (TR) during fermentation. Herein, we employed data independent acquisition and sequential window acquisition of all theoretical mass spectra based proteomic workflows to characterize proteome remodeling of an industrial strain, ScY01, responding to prolonged thermal stress or transient heat shock. By comparing the proteomic signatures of ScY01 in TR versus HSR as well as the HSR of the industrial strain versus a laboratory strain, our study revealed disparate response mechanisms of ScY01 during thermotolerant growth or under heat shock. In addition, through proteomics data mining for decoding transcription factor interaction networks followed by validation experiments, we uncovered the functions of two novel transcription factors, Mig1 and Srb2, in enhancing the thermotolerance of the industrial strain. This study has demonstrated that accurate and high throughput quantitative proteomics not only provides new insights into the molecular basis for complex microbial phenotypes but also pinpoints upstream regulators that can be targeted for improving the desired traits of industrial microorganisms.
author_names: Weidi Xiao

Xiaoxiao Duan

Yuping Lin

Qichen Cao

Shanshan Li

Yufeng Guo

Yuman Gan

Xianni Qi

Yue Zhou

Lihai Guo

Peibin Qin

Qinhong Wang

Wenqing Shui
title: Distinct Proteome Remodeling of Industrial Saccharomyces cerevisiae in Response to Prolonged Thermal Stress or Transient Heat Shock.
venue: Journal of proteome research
year: 2018

abstract: Abstract The Double Ceramic Layer Thermal Barrier Coating (DCL TBC) consists of a top ceramic layer (TC1) an inside ceramic layer (TC2) bond coat (BC) and alloy substrate. The top ceramic layer is made by new ceramic materials which has the lower thermal conductivity, such as LZ, LZ7C3, LMA etc. Although these materials have good high temperature performance and thermal insulation properties, their thermal expansion coefficients are very low which cause higher degree of mismatch with material properties of alloy substrate. The behavior of the stress buffer effect of the layer of TC2 is investigated aiming at the DCL TBC with the two ceramic layers as LZ7C3(TC1) and 8YSZ(TC2) A FE model of the DCL TBC is established and the stress of the TC1 during the thermal cycles is calculated. Results show that the layer of TC2 has the behaviors of stress buffer effect on reducing the stress of TC1 and reducing the influence of the TGO growth upon the stress of TC1. The inner mechanism of the stress buffer effect is investigated based on the influence of the thermal expansion coefficient r of the TC2 layer. Results show that the TC1 layer varies with the TC2 layer, having different thermal expansion coefficients; and the stress buffer effect is dominant, affected by the thermal expansion coefficients of the TC2 layer. The thermal expansion coefficient should be neither too large nor too low; if its values are too low or too large, the stress levels of TC1 are all high. The reasonable range of the thermal expansion coefficient is investigated. Aiming at the DCL TBC with the two ceramic layer thicknesses as 150 mm, the reasonable range of the thermal expansion coefficient of TC2 is from 10.35 degC 1 (x10 6) to 10.887 degC 1 (x10 6)
author_names: Meng Wei Han

Jihua Huang

Shu-Hsing Chen
title: Behavior and mechanism of the stress buffer effect of the inside ceramic layer to the top ceramic layer in a double ceramic layer thermal barrier coating
year: 2014

abstract: Using an IgG1 antibody as a model system, we have studied the mechanisms by which multidomain proteins aggregate at physiological pH when incubated at temperatures just below their lowest thermal transition. In this temperature interval, only minor changes to the protein conformation are observed. Light scattering consistently showed two coupled phases: an initial fast phase followed by several hours of exponential growth of the scattered intensity. This is the exact opposite of the lag time behavior typically observed in protein fibrillation. Dynamic light scattering showed the rapid formation of an aggregate species with a hydrodynamic radius of about 25 nm, which then increased in size throughout the experiment. Theoretical analysis of our light scattering data showed that the aggregate number density goes through a maximum in time providing compelling evidence for a coagulation mechanism in which aggregates fuse together. Both the analysis as well as size exclusion chromatography of incubated samples showed the actual increase in aggregate mass to be linear and reach saturation long before all molecules had been converted to aggregates. The CH2 domain is the only domain partly unfolded in the temperature interval studied, suggesting a pivotal role of this least stable domain in the aggregation process. Our results show that for multidomain proteins at temperatures below their thermal denaturation, transient unfolding of a single domain can prime the molecule for aggregation, and that the formation of large aggregates is driven by coagulation.
author_names: Christian Beyschau Andersen

Mauro Manno

Christian Rischel

Matthias Thorolfsson

Vincenzo Martorana
title: Aggregation of a multidomain protein: A coagulation mechanism governs aggregation of a model IgG1 antibody under weak thermal stress
venue: Protein science a publication of the Protein Society
year: 2010

abstract: ABSTRACT Coral bleaching is intensifying with global climate change. Although the causes for these catastrophic events are well understood, the cellular mechanism that triggers bleaching is not well established. Our understanding of coral bleaching processes is hindered by the lack of robust methods for studying interactions between host and symbiont at the single cell level. Here, we exposed coral explants to acute thermal stress and measured oxidative stress, more specifically, reactive oxygen species (ROS) in individual symbiont cells. Furthermore, we measured concentrations of dimethylsulphoniopropionate (DMSP) and dimethylsulphoxide (DMSO) to elucidate the role of these compounds in coral antioxidant function. This work demonstrates the application of coral explants for investigating coral physiology and biochemistry under thermal stress and delivers a new approach to study host symbiont interactions at the microscale, allowing us to directly link intracellular ROS with DMSP and DMSO dynamics. Summary: We use coral explants to link intracellular ROS in vivo under thermal stress with dimethylated sulphur compounds (DMSP and DMSO) supporting the involvement of these compounds in oxidative stress regulation.
author_names: Stephanie G Gardner

Jean-Baptiste Raina

Peter J Ralph

Katherina Petrou
title: Reactive oxygen species (ROS) and dimethylated sulphur compounds in coral explants under acute thermal stress
venue: Journal of Experimental Biology
year: 2017

abstract: To obtain the inner damage mechanism of a new type of thermal stress precision cropping bar.A thermal stress coupling model of the bar with an annular V shaped notch in the course of cooling was established.The stress field in the inner of the bar was evaluated by means of ANSYS software.The numerical simulation results show that the axial tension stress gets maximum at 0.34 mm from the bottom of the tip of the V shaped notch on the bar cross section.As the maximal stress and its nearby stress exceed the ultimate yield strength of the material,an annular damage strip in the bar cross section of the V shaped notch and close to V shaped notch tip appears.At the same cycle cool water velocity,the damage strip increases and then decreases with the increase of width of adiabatic boundary,and reaches to the maximum when the width of adiabatic boundary is 2 mm.With the same width of adiabatic boundary,the damage strip increases with the increase of water velocity,and it changes feebly when the water velocity is greater than 5 m/s.The damage strip disappears when the water velocity is equal to 1 m/s.The cropping experimental results show that the cropping time,by heat stress prefabricating an ideal crack at V shaped notch bottom,is reduced by 15% compared with the simplex variable frequency vibration cropping method without the action of the heat stress,which validates the thermal stress behaviors.
author_names: Tang Yong
title: Inner Damage Mechanism of Metal Bar with Thermal Stress
year: 2009

abstract: Abstract The residual stress and failure mode of thermal barrier coating (TBC) containing metallic bond coat (BC) and ceramic top coat (TC) with and without thermally grown oxide (TGO) were predicted using a micromechanical based finite element method (FEM) Actual microstructures of the TBC taken by a scanning electron microscope (SEM) were utilized as the representative volume elements (RVEs) in the computational model. Failure mode of the representative volume was numerically simulated as thermal stress localization during thermal cycle. Computations were done on the representative volume to quantitatively assess the effects of thermal and mechanical properties of the TBC constituents as well as the presence of TGO on the macroscopic mechanical response of the TBC. Comparisons of computed results with experiments verified that, the computational method can successfully predict residual stress and crack initiation mode of the studied thermal barrier coatings. Moreover, based on the computed results, both shear and normal failure mode occur in the thermal barrier coating which is in good agreement with experimental findings.
author_names: N Nayebpashaee

S H Seyedein

Mohammad Reza Aboutalebi

H Sarpoolaky

S M M Hadavi
title: Finite element simulation of residual stress and failure mechanism in plasma sprayed thermal barrier coatings using actual microstructure as the representative volume
year: 2016

abstract: ABSTRACT A change in temperature may be responsible for a variety of physiological stress responses in organisms, which are often associated with enhanced generation of reactive oxygen species (ROS) leading to oxidative damage. In the present study, the lipid peroxidation (LPO) levels of the oriental fruit fly, Bactrocera dorsalis (Hendel) were measured under thermal stress conditions of the relatively low 5, 2.5, 0, and 5 degC) or high (35, 37.5, and 40 degC) temperatures. Subsequently, the time related effect of thermal stress on activity of antioxidant enzymes including catalase (CAT) glutathione S transferases (GSTs) peroxidase (POX) superoxide dismutase (SOD) and total antioxidant capacity (T AOC) were systematically determined. The results showed that LPO levels increased significantly in a time dependent manner under thermal stress. The activities of CAT, GSTs, and SOD were significantly enhanced and likely provided a defense mechanism against oxidative damage due to the accumulation of ROS. POX and T AOC levels were not significantly modified. These results suggest that thermal stress induces oxidative stress, and antioxidant enzymes likely play an important role in reducing oxidative damage in B. dorsalis.
author_names: Fu-Xian Jia

Wei Dou

Fei Hu

Jin-Jun Wang
title: Effects of Thermal Stress on Lipid Peroxidation and Antioxidant Enzyme Activities of Oriental Fruit Fly, Bactrocera dorsalis (Diptera: Tephritidae)
year: 2011

abstract: Size exclusion chromatography with light scattering detection (SEC MALLS) was assessed as a means to characterize the type of bevacizumab aggregates that form under mechanical and thermal stress, quantitatively monitoring the aggregation kinetics. The analytical method was monitored and verified during routine use at two levels: (1) the "pre study" validation shows that the method is specific, linear, accurate, precise, robust and stability indicating; (2) the "in study" validation was verified by inserting quality control samples and the use of control charts, indicating that the analytical method is in statistical control and stable. The aggregation kinetics data were interpreted using a modified Lumry Eyring model, but the quality of the fit can be considered poor (R(2)>0.96) especially at higher temperatures. This indicates that the order of the reaction could not be reliably determined, suggesting a different degradation mechanism. The kinetic data set also fit the minimalistic Finke Watzky (F W) 2 step model, with an excellent quality of fit (R(2)>0.99) yielding the first quantitative rate constant for the steps of nucleation and growth in bevacizumab aggregation. The bevacizumab pharmaceutical preparation contains (initially) dimers, approximately 1.6% of bevacizumab total concentration, and the effect on aggregation kinetics of seeding was analyzed using the F W 2 step model assuming [B]00 (for the seeded case) The results suggested that the seeding had no impact on aggregation kinetics. Furthermore, the Arrhenius equation cannot be used to extrapolate the shelf life since no linear temperature dependence of the rate constant was found within the temperature range. Although the real time stability data provides the basis for determining the product shelf life, predictive methodologies such as Vogel Tammann Fulcher (VFT) or the Arrhenius approach can be misleading and result in overestimates of the product shelf life. However, they can be successfully applied to fixing the lower and upper limits of the aggregation rate, i.e. the best and worst case scenarios regarding the aggregation potential of the product. In conclusion, the present study evaluates the first application of the F W 2 step model to fitting and interpretation of experimental aggregation data for bevacizumab pharmaceutical preparations, using SEC MALLS in this context.
author_names: Alexis Oliva

Matias Llabres

Jose B Farina
title: Fitting bevacizumab aggregation kinetic data with the Finke Watzky two step model: Effect of thermal and mechanical stress.
venue: European journal of pharmaceutical sciences official journal of the European Federation for Pharmaceutical Sciences
year: 2015

abstract: Abstract The two dimensional (2D) graphene nanoplatelets (GNPs) were adopted to enhance the thermal conductivity of PBX. The results indicated that, the thermal conductivity of PBX was only slightly improved with very low GNP loading (0.05 wt% and 0.15 wt% However, a remarkable enhanced effect was observed at a relatively high GNP loading (0.5 wt% and 1 wt% The thermal conductivity of PBX had a nonlinear dependence on the GNPs loading. The nonlinear dependence of the thermal conductivity on GNPs content was fitted by an analytical model which incorporated all the effects. And the thermal conduction mechanism of GNPs based composite could change from series thermal structure to parallel thermal structure with the GNP loading increasing. Additionally, the calculated thermal shock resistance and thermal stress distribution of PBX was both enhanced with the GNP loading. Finally, the sensitivity of sensitive hexanitrohexaazaisowurtzitane (CL 20) based PBX composition could be improved by GNPs due to enhanced thermal conductivity.
author_names: Guansong He

Zhijian Yang

Xiaoyu Zhou

Jianhu Zhang

Liping Pan

Shi-jun Liu
title: Polymer bonded explosives (PBXs) with reduced thermal stress and sensitivity by thermal conductivity enhancement with graphene nanoplatelets
year: 2016