Mechanical stress affects dynamics and rheology of the human genome

Soft Matter ◽  
2022 ◽  
Author(s):  
Christina M. Caragine ◽  
Nikitas Kanellakopoulos ◽  
Alexandra Zidovska
Keyword(s):  
Mechanical Stress ◽  
Human Genome ◽  
Material Properties ◽  
Human Cells ◽  
Before And After

Using a novel noninvasive approach, we measure dynamics and rheology of the genome in live human cells before and after applying mechanical stress. We find that mechanical stress alters both dynamics and material properties of the genome.

Evaluating Mechanical Properties of Ceramics by Relative Methods

2007 ◽  
Vol 336-338 ◽  
pp. 2406-2410
Author(s):  
Yi Wang Bao ◽  
Xiao Xue Bu ◽  
Yan Chun Zhou ◽  
Li Zhong Liu
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Ceramic Coatings ◽  
Relative Method ◽  
Tempered Glass ◽  
Theoretic Analysis ◽  
Surface Strength ◽  
Indirect Approach ◽  
Before And After ◽  
The Relationship

A relative method, defined as indirect approach to evaluate the material properties via the relationship between unknown properties and a known property, is proposed to estimate some properties that could not be measured by the traditional methods for ceramics. Experiments and theoretic analysis based on the relative method were carried out in this study to estimate the properties in following aspects: determining the temperature dependence of elastic modulus of some machineable ceramics by comparing the deflections; obtaining the modulus and strength of ceramic coatings supported by substrates, from the variation in properties of the rectangular beam samples before and after coating; estimating the residual stresses in tempered glass by comparing the change in the surface strength after strengthening.

scholarly journals Saliva Leptin Levels in Tooth Movement during Initial Stage of Orthodontic Alignment: A Pilot Study

2017 ◽  
Vol 16 ◽  
pp. 1-8
Author(s):  
Noraini Abu Bakar ◽  
Wisam Kamil ◽  
Lina Al Bayati ◽  
Basma Ezzat Mustafa
Keyword(s):  
Pilot Study ◽  
Mechanical Stress ◽  
Orthodontic Treatment ◽  
Tooth Movement ◽  
Orthodontic Tooth Movement ◽  
Biologically Active ◽  
Orthodontic Appliances ◽  
Initial Alignment ◽  
Periodontal Tissues ◽  
Before And After

Introduction: During orthodontic tooth movement, the early response of periodontal tissues to mechanical stress is an acute inflammatory reaction. Mechanical stress from orthodontic appliances is believed to induce cells in the periodontal ligament (PDL) to form biologically active substances, such as enzymes and cytokines, responsible for connective tissue remodeling (Nishijima Y et al 2006). Leptin, a polypeptide hormone has been classified as a cytokine (Zhang et al 1994). Earlier findings concluded that leptin at high local concentrations protects the host from inflammation and infection as well as maintaining bone levels. It has been also suggested that leptin plays a significant role in bone formation by its direct effect on osteoblasts (Alparslan et al 2010). This pilot study aimed to study leptin in saliva and its association with tooth movement during initial orthodontic alignment. Objectives: To determine if there are any differences in saliva leptin level before and after orthodontic alignment. Material and methods: Ten orthodontic patients (7 girls and 3 boys; mean age, 16.76 ± 1.1 years) with crowding (up to 5mm) that required orthodontic fixed appliances, on a non-extraction basis as part of the treatment plan, were recruited in this longitudinal study. Orthodontic study models were constructed at baseline and at 6- weeks after orthodontic treatment commenced. Full fixed orthodontic appliances with initial 0.014” Nickel Titanium archwire placed. The amount of crowding was measured, before and after initial alignment with an electronic digital caliper (Max-Cal, Japan Micrometer Ltd, Tokyo, Japan) with an accuracy of up to 0.01mm. Unstimulated morning saliva sample were collected at all visits, after at least an 8-hour period of fasting and no-toothbrushing. After centrifugation (4000x g;10min), the samples were stored at -25C and tested using Leptin Abnova LEP Human ELISA kit (KA3080) which was subsequently analyzed. Subjects’ periodontal health status was also monitored throughout the study. Ethical approval (ID IREC 262) was received on 7th April 2014 from International Islamic University Malaysia Research Ethics Committee (IREC). Results: Leptin concentration in saliva was significantly decreased in a time-dependant manner (t(9)=8.60, p<0.001), from before orthodontic treatment (7016.45± 425.15 pg/mL) and 6 weeks after bond-up (4901.92±  238.64 pg/mL). Conclusion: Leptin concentration in saliva is decreased during orthodontic tooth movement in initial alignment stage.

Generation of a new adenovirus type 12-inducible fragile site by insertion of an artificial U2 locus in the human genome

1993 ◽  
Vol 13 (10) ◽  
pp. 6064-6070
Author(s):  
Y P Li ◽  
R Tomanin ◽  
J R Smiley ◽  
S Bacchetti
Keyword(s):  
Human Genome ◽  
Gene Cluster ◽  
Fragile Site ◽  
Adenovirus Type ◽  
Fragile Sites ◽  
Human Cells ◽  
Major Site ◽  
Chromosome 13 ◽  
Direct Assessment

Infection with adenovirus type 12 (Ad12) induces four fragile sites in the human genome (H.F. Stich, G.L. van Hoosier, and J.J. Trentin, Exp. Cell Res. 34:400-403, 1964; H. zur Hausen, J. Virol. 1:1174-1185, 1967). The major site, at 17q21-22, contains the U2 gene cluster, which is specifically disrupted by infection in at least a percentage of the cells (D.M. Durnam, J.C. Menninger, S.H. Chandler, P.P. Smith, and J.K. McDougall, Mol. Cell. Biol. 8:1863-1867, 1988). For direct assessment of whether the U2 locus is the target of the Ad12 effect, an artificial locus, constructed in vitro and consisting of tandem arrays of the U2 6-kbp monomer, was transfected into human cells. We report that integration of this artificial locus on the p arm of chromosome 13 creates a new Ad12-inducible fragile site.

Experimental Investigation of Mechanical Behavior of a Polyamide before and after Constrained Groove Pressing Process

2018 ◽  
Vol 36 ◽  
pp. 25-36
Author(s):  
Mohammed Salah Bennouna ◽  
Benaoumeur Aour ◽  
Fatiha Bouaksa ◽  
Saad Hamzaoui
Keyword(s):  
Experimental Investigation ◽  
Mechanical Behavior ◽  
Tensile Properties ◽  
Material Properties ◽  
Hold Time ◽  
Thermoplastic Polymer ◽  
Processed Material ◽  
Before And After ◽  
Number Of Cycles ◽  
Number Of Passes

In this paper an experimental investigation of mechanical behavior of a thermoplastic polymer (polyamide PA 66) processed by constrained groove pressing (CGP) using several passes is presented. To this end, corrugating and straightening tools are designed and manufactured. The effects of the number of passes and the hold time on the mechanical behavior of the polyamide have been highlighted. The obtained results show that the material properties and the microstructure are significantly altered under CGP process. It has been found that the microhardness and the tensile properties have been progressed accordingly to the number of cycles, especially when the samples are processed using a hold time of five minutes. Hence, it can be concluded that this latter plays a very important role on the reorientation and stabilization of the microstructure when the processed material is a polymer.

The effects of the Mulligan concept in ankylosing spondylitis: a report of two cases

2019 ◽  
Vol 26 (5) ◽  
pp. 1-10
Author(s):  
Songül Baglan-Yentur ◽  
Oğuzhan Mete ◽  
Zeynep Tuna ◽  
Abdurrahman Tufan ◽  
Deran Oskay
Keyword(s):  
Ankylosing Spondylitis ◽  
Mechanical Stress ◽  
Sacroiliac Joint ◽  
Joint Pain ◽  
Functional Performance ◽  
Morning Stiffness ◽  
Joint Damage ◽  
Sacroiliac Joint Pain ◽  
Before And After ◽  
Mulligan Concept

Introduction/Aims The first complaint in ankylosing spondylitis is usually sacroiliac joint pain and morning stiffness. Aside from inflammation, sacroiliac joint pain is related to joint damage and mechanical stress. Many different methods are applied in the treatment of sacroiliac joint pain. This study aimed to investigate the effects of sacroiliac joint mobilisation on pain, function and mobility in patients with ankylosing spondylitis. Methods Two patients presented with sacroiliac joint pain: a 46-year-old male and a 34-year-old female. Both patients received eight sessions of mobilisation with movement, according to the Mulligan concept (sacroiliac joint mobilisation and mechanical correction). Sessions were held at 4-day intervals over a 28-day period. The patients were assessed for sacroiliac joint mobilisation immediately before and after the first session and their pain, function and mobility were assessed at the second and eighth sessions. Findings A decrease in pain and increases in functional performance and mobility were noted in both cases at the end of eight sessions. Conclusions Sacroiliac joint mobilisation might be effective in improving pain, function and mobility in patients with ankylosing spondylitis. Further studies should be conducted with an increased number of participants to confirm these findings.

Influence of Mechanical Stress at High Temperatures on the Properties of Steels Intended for the Manufacture of Fuel Cladding for Generation IV Reactors

2017 ◽  
Vol 270 ◽  
pp. 246-252
Author(s):  
Zbyněk Špirit ◽  
Michal Chocholoušek ◽  
Marek Šíma
Keyword(s):  
Mechanical Stress ◽  
Material Properties ◽  
Fracture Mechanism ◽  
Nuclear Reactors ◽  
Mechanical Tests ◽  
Basic Material ◽  
Oxide Dispersion ◽  
Fuel Cladding ◽  
Thin Walled ◽  
Miniature Specimens

This paper describes the testing of thin-walled tubes made of oxide dispersion-hardened steels based on yttrium oxides. Series of mechanical and metallographic tests were carried out on the steels to evaluate the basic material properties. These steels are the candidate materials for the manufacture of the fuel cladding for generation IV nuclear reactors. Mechanical tests were performed on miniature specimens of Fe-9Cr and Fe-14Cr steels at 20 °C, 500 °C, and 625 °C under vacuum. Metallographic, fractographic and EBSD analyses were used to describe microstructure and fracture mechanism of the tested materials.

Feasibility of lipid mechanical extraction from viable Monoraphidium minutum

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Xavier Dommange ◽  
Philippe A. Tanguy ◽  
Mario Jolicoeur
Keyword(s):  
Mechanical Stress ◽  
Algal Cell ◽  
Lipid Extraction ◽  
Biofuel Production ◽  
Proof Of Concept ◽  
Extracellular Medium ◽  
Intracellular Lipids ◽  
Before And After ◽  
Low Levels ◽  
Mechanical Extraction

AbstractBackground. Mechanical stress was investigated as a mean to harvest microalgal lipids without affecting algal cells’ viability. Monoraphidium minutum was cultivated in laboratory-scale photobioreactors and suspension cultures were submitted to mechanical stress to compare a cyclone, a centrifuge and a homogenizer. Lipid content within the extracellular medium was analyzed prior to and after treatment, and the amount of released lipids was quantified. Algal cell viability was also evaluated before and after treatment.Results. After mechanical-stress treatments, 7.0 to 12.7% of the intracellular lipids of Monoraphidium minutum were released and found in the extracellular medium, while recovered algal cells presented low levels of disruption after treatments.Conclusions. To the best of our knowledge, this is the first proof-of-concept demonstration on the use of mechanical stress for lipid extraction from viable microalgae. Certain level of centrifugation proved to make algae release around 10% of their lipids to the extracellular medium. This mostly exploratory work calls for deeper investigation, paving the way for a biofuel production based on continuous lipid recovery and microalgae reuses.

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