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1.
Article in English | LILACS, BBO - Dentistry | ID: biblio-1351206

ABSTRACT

ABSTRACT Objective To compare the capacity of silver diamine fluoride (30%) and the bioactive giomer light-curing varnish for arresting ICDAS score 5 non-retentive caries lesions. Material and Methods An in vitro analytical study was conducted using 36 healthy primary teeth, in which a cavity was created, divided into 3 groups: control (distilled and deionized water), giomer-based light-curing varnish - Barrier Coat, and Silver Diamine Fluoride 30% - Cariestop (SDF). The samples were analyzed for mineral loss as measured by surface microhardness (SMH).The Knoop microhardness test was performed using the HVS-1000 microhardness tester. The data were compared by two-way analysis of variance - treatment and time (before and after treatment) followed by Tukey's post-test. The significance level adopted in all analyzes was 5%. Results The specimens treated with giomer showed higher SMH compared to the untreated group but were similar to those of the SDF group. The SDF group, on the other hand, showed no statistically significant difference from the control group (p=0.010). Conclusion The giomer varnish had a remineralizing effect on artificial dentinal caries.


Subject(s)
Tooth, Deciduous , In Vitro Techniques , Diamines , Hardness Tests/instrumentation , Analysis of Variance , Statistics, Nonparametric , Dental Caries
2.
World J Surg ; 44(8): 2777-2783, 2020 08.
Article in English | MEDLINE | ID: mdl-32322938

ABSTRACT

BACKGROUND: Severity of liver cirrhosis plays an important role in determining the safe extents of hepatectomy in patients with hepatocellular carcinoma (HCC). The aim of this study was to investigate whether direct liver stiffness measurement can help surgeons to evaluate the severity of liver cirrhosis in HCC patients. METHODS: Overall, 119 HCC patients who underwent open hepatectomy were retrospectively studied. The severity of liver cirrhosis was histologically staged using the Laennec staging system. Direct liver stiffness measurement was performed during operation using a sclerometer device named LX-C Shaw hardmeter, and its efficacy in assessing the severity of liver cirrhosis was compared with that of transient elastography (TE) and cirrhotic severity scoring (CSS) previously proposed by our team. RESULTS: Liver stiffness measured by LX-C Shaw hardmeter was significantly correlated with the severity of liver cirrhosis. Spearman correlation coefficients for the correlation between the severity of liver cirrhosis and direct liver stiffness measurement, TE, and CSS were 0.751, 0.454, and 0.705, respectively (all P < 0.001). The areas under the receiver operating characteristic curves (AUCs) of direct liver stiffness measurement were 0.891 for moderate cirrhosis and 0.944 for severe cirrhosis and superior to those of TE (0.735 and 0.776, respectively) and CSS (0.888 and 0.905, respectively). CONCLUSIONS: Direct liver stiffness measurement is a useful method in evaluating the severity of liver cirrhosis in HCC patients.


Subject(s)
Carcinoma, Hepatocellular/surgery , Elasticity Imaging Techniques/methods , Hardness Tests/instrumentation , Liver Cirrhosis/diagnosis , Liver Neoplasms/surgery , Liver , Adult , Biomechanical Phenomena , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/physiopathology , Female , Hardness , Hardness Tests/methods , Hepatectomy , Humans , Liver/diagnostic imaging , Liver/pathology , Liver/physiopathology , Liver/surgery , Liver Cirrhosis/diagnostic imaging , Liver Cirrhosis/pathology , Liver Cirrhosis/surgery , Liver Neoplasms/pathology , Liver Neoplasms/physiopathology , Male , Middle Aged , Retrospective Studies , Severity of Illness Index
3.
Article in English | LILACS, BBO - Dentistry | ID: biblio-1135499

ABSTRACT

Abstract Objective: To evaluate the effect of immersion and acid challenge with cola drink on color change (ΔE), Vickers hardness (VHN) and surface roughness (Ra) of artificial acrylic resin teeth. Material and Methods: The artificial teeth were divided into 6 groups (n= 8): TC (Trilux/Control), BC (Biotone/Control), TAC (Trilux/Acid challenge), BAC (Biotone/Acid challenge), TI (Trilux/Immersion) and BI (Biotone/Immersion). The teeth were embedded in acrylic resin and the labial side was serially polished to provide appropriate flat surface. The samples of TC, BC, TI, BI groups were immersed in artificial saliva and cola drink (coke) for 7 days, respectively. The acid challenge was performed with immersion of samples in coke for 5 min, and subsequently immersion in artificial saliva for 2h. This cycle was repeated at 4 times/day, during 7 days. The tests of VHN, ΔE and Ra were analyzed before and after the challenge and immersion groups. Data was analyzed by ANOVA, Tukey and T test (α = 0.05). Results: There was no difference in Ra values between groups after treatments. However, there was a decrease in VHN for all groups. BI (19.2 ± 0.3) presented significantly lower hardness than BAC (19.5 ± 0.9) and BC (20.2 ± 0.5). Groups BI (2.18 ± 0.41) and TI (1.50 ± 0.43) had statistically higher ΔE compared to the other groups. Conclusion: The hardness of resin teeth decreased after acid challenges, but the roughness surface was not affected. The color was more affected by the times of exposure in cola beverage and remineralization in artificial saliva, which were associated to the material degradation (AU).


Subject(s)
Tooth, Artificial , Acrylic Resins/chemistry , In Vitro Techniques/methods , Dental Prosthesis , Beverages , Brazil , Analysis of Variance , Cola/chemistry , Hardness Tests/instrumentation
4.
J Obstet Gynaecol ; 39(6): 757-762, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31020886

ABSTRACT

Postpartum haemorrhage (PPH) is a potentially life-threatening condition. Women undergoing caesarean section (CS) are at particular risk, and improvements in the management of PPH during CS are required. We investigated the use of a tissue hardness metre to quantify uterine contractions during CS with a view to its application for obstetric bleeding management. Fifty pregnant women at term who underwent elective CS were recruited. Using a tissue hardness metre, we measured uterine hardness twice during CS: after placental removal and before peritoneum closure. Each measurement was conducted at two standardised points: fundus and corpus uteri. Concurrently, obstetricians subjectively graded uterine contractions as weak, medium, or strong. The hardness metre accurately quantified the degree of uterine contraction assessed by the obstetricians, and could be an effective clinical tool for early recognition of intra-operative massive bleeding. IMPACT STATEMENT What is already known on this subject? Maintaining adequate uterine contraction leads to prevention of excessive blood loss, which decreases the incidence and severity of PPH. However, the assessment of uterine contraction is currently judged by obstetricians, who manually and subjectively evaluate uterine contraction according to uterine hardness. Therefore, uterine atony remains a clinical diagnosis without a universal definition. What do the results of this study add? The present study investigated the use of a tissue hardness metre to quantify uterine contractions during CS with a view to its application for obstetric bleeding management. The hardness metre was able to quantify the degree of uterine contraction perceived by obstetricians. Quantifying uterine hardness during CS correlates with the amount of intra-operative bleeding and is useful for early recognition of massive haemorrhage. What are the implications of these findings for clinical practice and/or further research? To improve the management of atonic PPH and avoid serious complications, the tissue hardness metre should be considered as a potential clinical tool during CS.


Subject(s)
Biomechanical Phenomena/physiology , Cesarean Section , Feasibility Studies , Postpartum Hemorrhage/therapy , Uterine Contraction/physiology , Uterus/physiopathology , Adult , Female , Hardness Tests/instrumentation , Humans , Middle Aged , Postpartum Hemorrhage/diagnosis , Postpartum Hemorrhage/physiopathology , Pregnancy
5.
ACS Sens ; 3(11): 2246-2253, 2018 11 26.
Article in English | MEDLINE | ID: mdl-30354079

ABSTRACT

This study proposes a skin analysis device using a truncate hollow cone (THC) probe for measuring both transepidermal water loss (TEWL) and skin hardness. Because skin health is closely related to the epidermal barrier function and skin mechanical property, it is important to measure their biophysical indicators at the same time, to understand skin conditions and diagnose skin disorders such as atopic dermatitis and systemic sclerosis. Previous skin analyzers, however, required different probes with different protocols for each biophysical indicators, which makes the measurement inconvenient and increases the measurement uncertainty. The present device consists of a THC probe equipped with humidity and force sensors, and an actuator that simultaneously measure both TEWL and skin hardness which indicate the integrity of the epidermal barrier function and the skin mechanical property, respectively. Using artificial reference skins, the prototype device showed the TEWL with a sensitivity and linearity of 0.011 (%/s)/(g/m2/h) and 99.5%, and the hardness with 0.075 N/(Shore 00) and 97.6%, respectively, which are within the appropriate range for the properties of human skin. The on-body measurement of five subjects showed that the proposed device could measure both the TEWL and skin hardness without any crosstalk from each other. The proposed device has great potential for in-depth analysis of the health status of the skin which could indicate various skin diseases.


Subject(s)
Epidermis/metabolism , Hardness Tests/instrumentation , Hardness , Humidity , Water Loss, Insensible , Adult , Equipment Design , Hardness Tests/methods , Humans , Male , Regression Analysis , Water/analysis , Water/metabolism
6.
J Acupunct Meridian Stud ; 10(5): 340-345, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29078969

ABSTRACT

INTRODUCTION: For developing a hardness multipoint measurement system for understanding hardness distribution on biological body surfaces, we investigated the spring strength of the contact portion main axis of a biological tissue hardness meter (product name: PEK). METHODS: We measured the hardness of three-layered sheets of six types of gel sheets (90 mm × 60 mm × 6 mm) constituting the acupuncture practice pads, with PEK measurements of 1.96 N, 2.94 N, 3.92 N, 4.90 N, 5.88 N, 6.86 N, 7.84 N, 8.82 N, and 9.81 N of the main axis spring strength. We obtained measurements 10 times for the gel sheets and simultaneously measured the load using a digital scale. We measured the hardness distribution of induration embedded and breast cancer palpation models, with a main axis with 1.96 N, 4.90 N, and 9.81 N spring strengths, to create a two-dimensional Contour Fill Chart. RESULTS: Using 4.90 N spring strength, we could obtain measurement loads of ≤3.0 N, and the mean hardness was 5.14 mm. This was close to the median of the total measurement range 0.0-10.0 mm, making the measurement range the largest for this spring strength. We could image the induration of the induration-embedded model regardless of the spring strength. CONCLUSION: Overall, 4.90 N spring strength was best suited for imaging cancer in the breast cancer palpation model.


Subject(s)
Breast/physiology , Hardness Tests/instrumentation , Hardness Tests/methods , Models, Biological , Acupuncture Therapy , Breast Neoplasms , Female , Humans
7.
IEEE Trans Biomed Eng ; 64(7): 1535-1546, 2017 07.
Article in English | MEDLINE | ID: mdl-28113299

ABSTRACT

Noninvasive measurement of tissue viscoelastic properties is gaining more attention for screening and diagnostic purposes. Recently, measuring dynamic response of tissue under a constant force has been studied for estimation of tissue viscoelastic properties in terms of retardation times. The essential part of such a test is an instrument that is capable of creating a controlled axial force and is suitable for clinical applications. Such a device should be lightweight, portable, and easy to use for patient studies to capture tissue dynamics under external stress. In this paper, we present the design of an automated compression device for studying the creep response of materials with tissue-like behaviors. The device can be used to apply a ramp-and-hold force excitation for a predetermined duration of time and it houses an ultrasound probe for monitoring the creep response of the underlying tissue. To validate the performance of the device, several creep tests were performed on tissue-mimicking phantoms, and the results were compared against those from a commercial mechanical testing instrument. Using a second-order Kelvin-Voigt model and surface measurement of the forces and displacements, retardation times T1 and T2 were estimated from each test. These tests showed strong agreement between our automated compression device and the commercial mechanical testing system, with an average relative error of 2.9% and 12.4%, for T1 and T2, respectively. Also, we present the application of compression device to measure local retardation times for four different phantoms with different size and stiffness.


Subject(s)
Elastic Modulus/physiology , Elasticity Imaging Techniques/instrumentation , Hardness Tests/instrumentation , Micro-Electrical-Mechanical Systems/instrumentation , Physical Stimulation/instrumentation , Transducers, Pressure , Viscosity , Equipment Design , Equipment Failure Analysis , Hardness Tests/methods , Humans , Phantoms, Imaging , Physical Stimulation/methods , Reproducibility of Results , Sensitivity and Specificity
8.
Skin Res Technol ; 23(3): 272-282, 2017 Aug.
Article in English | MEDLINE | ID: mdl-27896851

ABSTRACT

BACKGROUND: A new electro-mechanical device for measuring the lateral stiffness of the skin is now available. It basically allows to recording the forces that the skin opposes to a lateral displacement (1-2 mm) of a pinching type movement. Preliminary assays of this device to various skin sites and an artificial substrate aimed at defining its major characteristics (sensitivity, reproducibility, variations according to skin site). METHODS: The calibration of the device (Khelometer® ) and assessment of its reproducibility were carried out through the use of elastometer substrates of various stiffness's. The device was then used, in vivo, at different skin sites (scalp, inner and outer forearms, cheeks) of 213 healthy Japanese women of various ages. The short-time effect of a hydrating regimen (7% glycerol) was recorded on the outer forearm. RESULTS: This new device offers an appreciable reproducibility in vitro and in vivo (coefficient of variation of 2-4% and 5-14%, respectively). Unlike other biophysical methods, the Khelometer® can be easily applied onto the human scalp that shows a higher stiffness than the two other skin sites, increasing with age and presence of alopecia. In all the three studied skin sites, the impact of age leads to significantly higher lateral skin stiffness (LSS, expressed as N/mm) values. The latter were found significantly different between the two sides of the forearms where the outer (sun-exposed) side showed statistically slightly higher LSS, than the unexposed inner side. LSS values found on cheeks (≈0.5 N/mm) were about four times lower than those of the scalp (≈2 N/mm) and about half those of forearms (≈1 N/mm). The effect of a 7% glycerol based formula was recorded 20 min post application onto the forearm, leading to a slight drop in LSS (approx. 15%) as compared to a vehicle-applied skin site. CONCLUSION: These preliminary studies clearly indicate that this new device, applicable to any skin site, offers appreciable assets such as sensitivity and reproducibility. Accordingly, it appears as a new approach in the non-invasive biophysical measurements of the skin surface, in both advanced and applied research investigations.


Subject(s)
Biomechanical Phenomena/physiology , Hardness Tests/instrumentation , Skin Abnormalities/pathology , Skin/pathology , Adult , Aged , Aging/physiology , Asian People , Cryoprotective Agents/pharmacology , Elastomers , Female , Forearm/physiology , Glycerol/administration & dosage , Glycerol/pharmacology , Humans , Middle Aged , Preliminary Data , Reproducibility of Results , Scalp/physiology , Skin/drug effects , Skin Physiological Phenomena
9.
Skin Res Technol ; 23(2): 155-168, 2017 May.
Article in English | MEDLINE | ID: mdl-27546316

ABSTRACT

BACKGROUND: One of the key strategies for anti-ageing in the cosmetics industry today is to target the structural changes responsible for ptosis of the skin, given its impact on age perception. Several objective and non-invasive methods are available to characterise the biomechanical properties of the skin, which are operator-dependent, involving skin contact and providing single-dimensional numerical descriptions of skin behaviour. The research introduces the DynaSKIN, a device using non-contact mechanical pressure in combination with fringe projection to quantify and visualise the skin response in 3-dimensions. We examine the age correlation of the measurements, how they compare with the Cutometer® , and measure skin dynamics following application of a skincare regimen containing established anti-ageing ingredients. METHODS: DynaSKIN and Cutometer® measurements were made on the cheek of 80 Caucasian women (18-64 years). DynaSKIN volume, mean depth and maximum depth parameters were correlated with age and 15 Cutometer® parameters. Subsequently, the firming efficacy of a skincare regimen featuring acetyl aspartic acid (AAA) and a peptide complex was examined in a cohort of 41 volunteers. RESULTS: DynaSKIN volume, mean depth and maximum depth parameters correlate with age and the Cutometer® parameters that are associated with the skin relaxation phase (R1, R2, R4, R5, R7 and F3). Furthermore, the DynaSKIN captured significant improvements in skin firmness delivered by the skincare regimen. CONCLUSION: The DynaSKIN is a novel device capable of capturing skin biomechanics at a high level of specificity and successfully detected the firming properties of a skincare regimen. Its independent measuring principle, consumer relevance and skin firmness 3D visualisation capabilities bring objectivity and novelty to product efficacy substantiation evaluation.


Subject(s)
Aspartic Acid/administration & dosage , Hardness Tests/instrumentation , Hardness/drug effects , Hardness/physiology , Skin Cream/administration & dosage , Skin Physiological Phenomena/drug effects , Administration, Cutaneous , Adolescent , Adult , Compressive Strength/drug effects , Compressive Strength/physiology , Equipment Design , Equipment Failure Analysis , Female , Humans , Middle Aged , Physical Stimulation/instrumentation , Physical Stimulation/methods , Reproducibility of Results , Sensitivity and Specificity , Skin Care/methods , Treatment Outcome , Young Adult
10.
Pharm Dev Technol ; 22(2): 246-255, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27607150

ABSTRACT

Tablet hardness, a measure of the breaking force of a tablet, is based on numerous factors. These include the shape of the tablet and the mode of the application of force. For instance, when a pentagonal-shaped tablet was tested with a traditional hardness tester with flat platens, there was a large variation in hardness measurements. This was due to the propensity of vertices of the tablet to crush, referred to as an "improper break". This article describes a novel approach to measure the hardness of pentagonal-shaped tablets using modified platens. The modified platens have more uniform loading than flat platens. This is because they reduce loading on the vertex of the pentagon and apply forces on tablet edges to generate reproducible tablet fracture. The robustness of modified platens was assessed using a series of studies, which included feasibility and Gauge Repeatability & Reproducibility (R&R) studies. A key finding was that improper breaks, generated frequently with a traditional hardness tester using flat platens, were eliminated. The Gauge R&R study revealed that the tablets tested with novel platens generated consistent values in hardness measurements, independent of batch, hardness level, and day of testing, operator and tablet dosage strength.


Subject(s)
Hardness Tests/instrumentation , Tablets/chemistry , Drug Compounding , Equipment Design , Hardness , Hardness Tests/methods , Reproducibility of Results
11.
J Biomech Eng ; 139(1)2017 01 01.
Article in English | MEDLINE | ID: mdl-27760249

ABSTRACT

A triaxial force-sensitive microrobot was developed to dynamically perturb skin in multiple deformation modes, in vivo. Wiener static nonlinear identification was used to extract the linear dynamics and static nonlinearity of the force-displacement behavior of skin. Stochastic input forces were applied to the volar forearm and thenar eminence of the hand, producing probe tip perturbations in indentation and tangential extension. Wiener static nonlinear approaches reproduced the resulting displacements with variances accounted for (VAF) ranging 94-97%, indicating a good fit to the data. These approaches provided VAF improvements of 0.1-3.4% over linear models. Thenar eminence stiffness measures were approximately twice those measured on the forearm. Damping was shown to be significantly higher on the palm, whereas the perturbed mass typically was lower. Coefficients of variation (CVs) for nonlinear parameters were assessed within and across individuals. Individual CVs ranged from 2% to 11% for indentation and from 2% to 19% for extension. Stochastic perturbations with incrementally increasing mean amplitudes were applied to the same test areas. Differences between full-scale and incremental reduced-scale perturbations were investigated. Different incremental preloading schemes were investigated. However, no significant difference in parameters was found between different incremental preloading schemes. Incremental schemes provided depth-dependent estimates of stiffness and damping, ranging from 300 N/m and 2 Ns/m, respectively, at the surface to 5 kN/m and 50 Ns/m at greater depths. The device and techniques used in this research have potential applications in areas, such as evaluating skincare products, assessing skin hydration, or analyzing wound healing.


Subject(s)
Hardness Tests/methods , Hardness/physiology , Models, Biological , Models, Statistical , Physical Stimulation/methods , Skin Physiological Phenomena , Anisotropy , Computer Simulation , Hardness Tests/instrumentation , Humans , Nonlinear Dynamics , Physical Stimulation/instrumentation , Reproducibility of Results , Robotics/instrumentation , Robotics/methods , Sensitivity and Specificity , Stochastic Processes , Stress, Mechanical , Viscosity
12.
IEEE Trans Neural Syst Rehabil Eng ; 25(5): 426-435, 2017 05.
Article in English | MEDLINE | ID: mdl-27244744

ABSTRACT

Biomechanical tissue properties have been hypothesized to play a critical role in the quantification of prosthetic socket production for individuals with limb amputation. In this investigation, a novel indenter platform is presented and its performance evaluated for the purposes of residual-limb tissue characterization. The indenter comprised 14 position- and force-controllable actuators that circumferentially surround a biological residuum to form an actuator ring. Each indenter actuator was individually controllable in position ( [Formula: see text] accuracy) and force (330 mN accuracy) at a PC controller feedback rate of 500 Hz, allowing for a range of measurement across a residual stump. Data were collected from 162 sensors over an EtherCAT fieldbus to characterize the mechanical hyperviscoelastic tissue response of two transtibial residual-limbs from a study participant with bilateral amputations. At five distinct anatomical locations across the residual-limb, force versus deflection data-including hyperviscoelastic tissue properties-are presented, demonstrating the accuracy and versatility of the multi-indenter platform for residual-limb tissue characterization.


Subject(s)
Amputation Stumps/physiopathology , Elastic Modulus , Hardness Tests/instrumentation , Palpation/instrumentation , Physical Stimulation/instrumentation , Viscosity , Equipment Design , Equipment Failure Analysis , Hardness Tests/methods , Humans , Knee Joint/physiopathology , Micro-Electrical-Mechanical Systems/instrumentation , Micro-Electrical-Mechanical Systems/methods , Physical Stimulation/methods , Reproducibility of Results , Sensitivity and Specificity
13.
Ultrasound Med Biol ; 41(8): 2266-71, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25944285

ABSTRACT

The goals of this study were to compare neck and shoulder stiffness values determined by shear wave ultrasound elastography with those obtained with a muscle hardness meter and to verify the correspondence between objective and subjective stiffness in the neck and shoulder. Twenty-four young men and women participated in the study. Their neck and shoulder stiffness was determined at six sites. Before the start of the measurements, patients rated their present subjective symptoms of neck and shoulder stiffness on a 6-point verbal scale. At all measurement sites, the correlation coefficients between the values of muscle hardness indices determined by the muscle hardness meter and shear wave ultrasound elastography were not significant. Furthermore, individuals' subjective neck and shoulder stiffness did not correspond to their objective symptoms. These results suggest that the use of shear wave ultrasound elastography is essential to more precisely assess neck and shoulder stiffness.


Subject(s)
Elasticity Imaging Techniques/methods , Hardness Tests/methods , Muscle, Skeletal/diagnostic imaging , Muscle, Skeletal/physiology , Neck/physiopathology , Shoulder/physiopathology , Elastic Modulus/physiology , Female , Hardness/physiology , Hardness Tests/instrumentation , Humans , Male , Neck/diagnostic imaging , Physical Examination/instrumentation , Physical Examination/methods , Reproducibility of Results , Sensitivity and Specificity , Shoulder/diagnostic imaging , Young Adult
15.
J Surg Res ; 192(2): 521-30, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25214261

ABSTRACT

BACKGROUND: We aimed to test whether testis rigidity (hardness) measured using a newly-designed device we previously introduced would offer more reliable assessment of histologic damage in undescended testes than conventional methods (consistency feel at palpation, volume measurement). MATERIALS AND METHODS: Forty-five 18-d-old Lewis rats underwent surgical inhibition of descent of left testes and were followed to 40 (n = 16), 63 (n = 14), or 90 days (n = 15). Another 45 18-d-old Lewis rats were sham operated (left side) and followed likewise (n = 14, n = 15, and n = 16). At the designated time points, testes were exposed bilaterally, rigidity was measured, and consistency at palpation was scored; testes were removed and subjected to length, width, weight measurements, volume calculation, and histomorphometry (mean Johnsen score [MJS], mean tubular diameter [MTD], and mean capsule width [MCW]). Testes of experimental group were compared with ipsilateral testes of sham-operated rats. RESULTS: At all time points, undescended testes had decreased rigidity, MJS, and MTD, increased MCW, decreased volume and weight; contralateral testes remained unaffected. Rigidity was associated only with MJS and MTD, and most strongly with MJS (multiple stepwise linear regression, F = 694.44, P < 0.0005). MJS could be precisely predicted from rigidity: MJS = 0.699 × testis rigidity (F = 1358.82, P < 0.0005). This model showed good fit between predicted and actual MJS values (R(2) = 0.94), low error, nonsignificant bias, sensitivity 75% and specificity 90%. Model validation showed low prediction error and nonsignificant bias, indicating generalizability. Testis volume and palpation proved imprecise MJS predictors. CONCLUSIONS: Testis rigidity is an effective predictor of histologic damage in rat undescended testes, with diagnostic value superior to testis palpation scoring and volume measurement.


Subject(s)
Cryptorchidism , Hardness Tests/methods , Testis/pathology , Testis/physiopathology , Animals , Biopsy , Calibration , Cryptorchidism/diagnosis , Cryptorchidism/pathology , Cryptorchidism/physiopathology , Elasticity , Equipment Design , Hardness Tests/instrumentation , Male , Palpation , Predictive Value of Tests , Rats, Inbred Lew , Spermatids/cytology , Spermatocytes/cytology , Spermatogenesis , Torque
16.
Opt Lett ; 39(16): 4835-8, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-25121887

ABSTRACT

We demonstrate an interferometric fiber-optic bending/nano-displacement sensor based on a plastic dual-core fiber. The light coupled into the two fiber cores is first guided along the fiber, and then reflected by the mirror coated at the fiber end. Reflected light coming out of the fiber produces interference that shifts as the fiber bends. The interference shift is interrogated using a slit and a photodetector. The resolution of our sensor is ∼3×10(-4) m(-1) for sensing the bending curvature, and ∼70 nm for sensing the displacement.


Subject(s)
Fiber Optic Technology/instrumentation , Hardness Tests/instrumentation , Interferometry/instrumentation , Lenses , Plastics/chemistry , Refractometry/instrumentation , Transducers , Elastic Modulus , Equipment Design , Equipment Failure Analysis , Light , Motion , Nanotechnology/instrumentation , Scattering, Radiation , Stress, Mechanical
17.
ScientificWorldJournal ; 2014: 248792, 2014.
Article in English | MEDLINE | ID: mdl-24995354

ABSTRACT

The initiating explosive devices are prohibited in rock breaking near the goaf of the highly gassy mine. It is effective and applicable to cracking the hard roof with static cracking agent. By testing the static cracking of cubic limestone (size: 200 × 200 × 200 mm) with true triaxial rock mechanics testing machine under the effect of bidirectional stress and by monitoring the evolution process of the cracks generated during the acoustic emission experiment of static cracking, we conclude the following: the experiment results of the acoustic emission show that the cracks start from the lower part of the hole wall until they spread all over the sample. The crack growth rate follows a trend of "from rapidness to slowness." The expansion time is different for the two bunches of cracks. The growth rates can be divided into the rapid increasing period and the rapid declining period, of which the growth rate in declining period is less than that in the increasing period. Also, the growth rate along the vertical direction is greater than that of the horizontal direction. Then the extended model for the static cracking is built according to the theories of elastic mechanics and fracture mechanics. Thus the relation formula between the applied forces of cracks and crack expansion radius is obtained. By comparison with the test results, the model proves to be applicable. In accordance with the actual geological situation of Yangquan No. 3 Mine, the basic parameters of manpower manipulated caving breaking with static crushing are settled, which reaps bumper industrial effects.


Subject(s)
Coal Mining/methods , Environment , Hardness Tests/methods , Renewable Energy , Acoustics/instrumentation , Coal Mining/instrumentation , Hardness Tests/instrumentation , Humans
18.
Skin Res Technol ; 20(4): 422-8, 2014 Nov.
Article in English | MEDLINE | ID: mdl-24506419

ABSTRACT

BACKGROUND: Long-term exposure to sunlight changes skin features like amount of facial wrinkling and skin elasticity, which is useful in estimating skin health and age-related changes. Skin elasticity is evaluated by quantitative methods such as the noninvasive suction device Cutometer(®) , which is widely used to evaluate regional body-elasticity differences and correlate these findings with the results of other instrumental data. Few field studies have been done with the Ballistometer(®) device, another noninvasive method for measuring skin elasticity. METHOD: In this study, we measured the skin elasticity of each subject's forehead, cheek, and volar forearm using two devices with different means of obtaining quantitative measurements - Ballistometer(®) (Diastron Ltd.) and Cutometer(®) (CK electronics). RESULTS: The results from testing with the Ballistometer(®) and Cutometer(®) devices showed that the degree of skin elasticity of the volar forearm is greater than those found on the cheek and forehead. The parameters measured by the Ballistometer(®) showed high correlation patterns. On the cheek skin, the correlation coefficient between Ballisto-parameters and R parameters (R0, R3, R8) was higher than other skin sites. CONCLUSION: Taken together, R parameters measured by the Cutometer(®) device have been widely distributed in the evaluation of skin elasticity in research and cosmetics. Although the methodologies are different, the Ballistometer(®) device is also a useful tool to evaluate skin elasticity.


Subject(s)
Elastic Modulus/physiology , Hardness Tests/instrumentation , Manometry/instrumentation , Physical Stimulation/instrumentation , Skin Physiological Phenomena , Adult , Equipment Design , Equipment Failure Analysis , Female , Humans , Reproducibility of Results , Sensitivity and Specificity , Stress, Mechanical
19.
Skin Res Technol ; 20(3): 347-54, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24267492

ABSTRACT

BACKGROUND: Indentation techniques haves been applied to measure stiffness of human soft tissues. Tissue properties and geometry of the indentation instrument control the measured response. METHODS: Mechanical roles of different soft tissues were characterized to understand the performance of the indentation instrument. An optimal instrument design was investigated. Experimental indentations in forearm of human subjects (N = 11) were conducted. Based on peripheral quantitative computed tomography imaging, a finite element (FE) model for indentation was created. The model response was matched with the experimental data. RESULTS: Optimized values for the elastic modulus of skin and adipose tissue were 130.2 and 2.5 kPa, respectively. The simulated indentation response was 3.9 ± 1.2 (mean ± SD) and 4.9 ± 2.0 times more sensitive to changes in the elastic modulus of the skin than to changes in the elastic modulus of adipose tissue and muscle, respectively. Skin thickness affected sensitivity of the instrument to detect changes in stiffness of the underlying tissues. CONCLUSION: Finite element modeling provides a feasible method to quantitatively evaluate the geometrical aspects and the sensitivity of an indentation measurement device. Systematically, the skin predominantly controlled the indentation response regardless of the indenter geometry or variations in the volume of different soft tissues.


Subject(s)
Adipose Tissue/physiology , Hardness Tests/instrumentation , Hardness/physiology , Models, Biological , Muscle, Skeletal/physiology , Skin Physiological Phenomena , Adult , Computer Simulation , Elastic Modulus/physiology , Equipment Design , Equipment Failure Analysis , Female , Humans , Male , Physical Examination/instrumentation , Reproducibility of Results , Sensitivity and Specificity , Stress, Mechanical
20.
J Biomech Eng ; 136(2): 021025, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24317364

ABSTRACT

Preservation of structural integrity inside cells and at cell-extracellular matrix (ECM) interfaces is a key challenge during freezing of biomaterials. Since the post-thaw functionality of cells depends on the extent of change in the cytoskeletal structure caused by complex cell-ECM adhesion, spatiotemporal deformation inside the cell was measured using a newly developed microbead-mediated particle tracking deformetry (PTD) technique using fibroblast-seeded dermal equivalents as a model tissue. Fibronectin-coated 500 nm diameter microbeads were internalized in cells, and the microbead-labeled cells were used to prepare engineered tissue with type I collagen matrices. After a 24 h incubation the engineered tissues were directionally frozen, and the cells were imaged during the process. The microbeads were tracked, and spatiotemporal deformation inside the cells was computed from the tracking data using the PTD method. Effects of particle size on the deformation measurement method were tested, and it was found that microbeads represent cell deformation to acceptable accuracy. The results showed complex spatiotemporal deformation patterns in the cells. Large deformation in the cells and detachments of cells from the ECM were observed. At the cellular scale, variable directionality of the deformation was found in contrast to the one-dimensional deformation pattern observed at the tissue scale, as found from earlier studies. In summary, this method can quantify the spatiotemporal deformation in cells and can be correlated to the freezing-induced change in the structure of cytosplasm and of the cell-ECM interface. As a broader application, this method may be used to compute deformation of cells in the ECM environment for physiological processes, namely cell migration, stem cell differentiation, vasculogenesis, and cancer metastasis, which have relevance to quantify mechanotransduction.


Subject(s)
Cell Adhesion/physiology , Cryopreservation/methods , Extracellular Matrix/metabolism , Fibrillar Collagens/metabolism , Fibroblasts/physiology , Freezing , Hardness Tests/methods , Cell Separation/instrumentation , Cell Separation/methods , Cell Size , Cells, Cultured , Elastic Modulus/physiology , Equipment Design , Fibroblasts/cytology , Hardness Tests/instrumentation , Humans , Materials Testing , Reproducibility of Results , Sensitivity and Specificity , Spatio-Temporal Analysis
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