scholarly journals Elasticity Changes in the Crystalline Lens during Oxidative Damage and the Antioxidant Effect of Alpha-Lipoic Acid Measured by Optical Coherence Elastography

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 207
Author(s):  
Hongqiu Zhang ◽  
Manmohan Singh ◽  
Achuth Nair ◽  
Kirill V. Larin ◽  
Salavat R. Aglyamov
Keyword(s):  
Oxidative Damage ◽  
Young’S Modulus ◽  
Lipoic Acid ◽  
Ex Vivo ◽  
Young's Modulus ◽  
Crystalline Lens ◽  
Biomechanical Properties ◽  
Optical Coherence ◽  
Age Related ◽  
Significant Difference

Age-related cataracts are one of the most prevalent causes of visual impairment around the world. Understanding the mechanisms of cataract development and progression is essential to enable early clinical diagnosis and treatment to preserve visual acuity. Reductive chemicals are potential medicines effective on cataract treatment. In this work, we investigated the cataract-induced oxidative damage in the crystalline lens and a kind of reductant, α-lipoic acid (ALA), ability to reduce the damage. We created oxidative environment to investigate the relationship between the progression of oxidative cataract and lenticular biomechanical properties measured by dynamic optical coherence elastography in porcine crystalline lenses ex vivo. The efficacy of ALA to minimize the stiffening of the lens was also quantified. The results showed a significant increase in Young’s modulus of the lens due to the formation of the oxidative cataract. We found a statistically significant difference between Young’s modulus of the lenses stored in phosphate-buffered saline and ALA solution after incubation in H2O2 solution for 3 h (43.0 ± 9.0 kPa versus 20.7 ± 3.5 kPa, respectively). These results show that the lens stiffness increases during oxidative cataract formation, and ALA has the potential to reverse stiffening of the lens caused by oxidative damage.

Quantification of biomechanical properties of human corneal scar using acoustic radiation force optical coherence elastography

2021 ◽  
pp. 153537022110618
Author(s):  
Xiao Han ◽  
Yubao Zhang ◽  
Yirui Zhu ◽  
Yanzhi Zhao ◽  
Hongwei Yang ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Acoustic Radiation ◽  
Ex Vivo ◽  
Young's Modulus ◽  
Radiation Force ◽  
Biomechanical Properties ◽  
Acoustic Radiation Force ◽  
Optical Coherence ◽  
Corneal Surgery ◽  
Corneal Scar

Biomechanical properties of corneal scar are strongly correlated with many corneal diseases and some types of corneal surgery, however, there is no elasticity information available about corneal scar to date. Here, we proposed an acoustic radiation force optical coherence elastography system to evaluate corneal scar elasticity. Elasticity quantification was first conducted on ex vivo rabbit corneas, and the results validate the efficacy of our system. Then, experiments were performed on an ex vivo human scarred cornea, where the structural features, the elastic wave propagations, and the corresponding Young’s modulus of both the scarred region and the normal region were achieved and based on this, 2D spatial distribution of Young’s modulus of the scarred cornea was depicted. Up to our knowledge, we realized the first elasticity quantification of corneal scar, which may provide a potent tool to promote clinical research on the disorders and surgery of the cornea.

scholarly journals Modulating physical properties of porcine urethra with injection of novel biomimetic proteoglycans ex vivo

2019 ◽  
Vol 9 (4) ◽  
pp. 20190013 ◽  
Author(s):  
Alicia S. Kriete ◽  
Katsiaryna Prudnikova ◽  
Michele S. Marcolongo
Keyword(s):  
Urinary Incontinence ◽  
Physical Properties ◽  
Young’S Modulus ◽  
Water Uptake ◽  
Ex Vivo ◽  
Young's Modulus ◽  
Radial Expansion ◽  
Significant Difference ◽  
Testing Data ◽  
Phosphate Buffered Saline

Urinary incontinence is a significant challenge for women who are affected by it. We propose augmenting the tissue structure to restore normal biomechanics by molecularly engineering the tissue using a novel family of biomimetic proteoglycans (BPGs). This work examines the ability of BPGs to modulate the mechanical and physical properties of porcine urethras ex vivo to determine the feasibility of BPGs to be implemented as molecular treatment for stress urinary incontinence (SUI). We investigated compliance by performing a unique radial expansion testing method using urethras from six- to nine-month-old pigs. The urethras were injected with 0.5 ml BPG solution at three sites every approximately 120° (conc.: 25 mg ml −1 , 50 mg ml −1 and 75 mg ml −1 in 1× phosphate-buffered saline (PBS); n = 4 per group) and compared them with PBS-injected controls. Young's modulus was calculated by treating the urethra as a thin-walled pressure vessel. A water uptake study was performed by soaking 10 mm urethra biopsy samples that were injected with 0.1 ml BPG solution (conc.: 50 mg ml −1 , 100 mg ml −1 and 200 mg ml −1 in 1× PBS; n = 6 per group) in 5 ml PBS for 24 h. Although there was no significant difference in Young's modulus data, there were differences between groups as can be seen in the raw radial expansion testing data. Results showed that BPGs have the potential to increase hydration in samples, and that there was a significant difference in water uptake between BPG-injected samples and the controls (100 mg ml −1 samples versus PBS samples, p < 0.05). This work shows that BPGs have the potential to be implemented as a molecular treatment for SUI, by restoring the diminished proteoglycan content and subsequently increasing hydration and improving the compliance of urethral tissue.

Evaluation of Young’s Modulus in Achilles Tendons with Diabetic Neuroarthropathy

2005 ◽  
Vol 95 (3) ◽  
pp. 242-246 ◽  
Author(s):  
William P. Grant ◽  
Eric J. Foreman ◽  
Anne S. Wilson ◽  
Dwayne A. Jacobus ◽  
Renee M. Kukla
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Normal Tendon ◽  
Significant Difference ◽  
New Finding ◽  
Tendo Achillis

The Achilles tendon of the patient with Charcot’s foot neuroarthropathy has significantly altered physical properties compared with a normal tendon. Twenty-nine Achilles tendons from patients with Charcot’s foot (n = 20) and non-Charcot’s foot controls (n = 9) were loaded onto a biomechanical testing instrument. The biomechanical properties of the Charcot and control tendons were determined and the tendons were evaluated for differences in ultimate tensile strength and elasticity (Young’s modulus). Biomechanical test data show that there is a significant difference in ultimate tensile strength and elasticity between tendons of patients with Charcot’s foot and those of non-Charcot’s controls. The term diabetic tendo Achillis equinus is introduced as a new finding in diabetic neuroarthropathy. (J Am Podiatr Med Assoc 95(3): 242–246, 2005)

The influence of osteopathic correction on the rate of various rhythms of the body

2019 ◽  
pp. 64-71 ◽  
Author(s):  
A. E. Chernikova ◽  
Yu. P. Potekhina
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Age Groups ◽  
Biomechanical Properties ◽  
Dispersion Analysis ◽  
The Body ◽  
Body Tissues ◽  
Age Related ◽  
Significant Difference ◽  
Before And After

Introduction. An osteopathic examination determines the rate, the amplitude and the strength of the main rhythms (cardiac, respiratory and cranial). However, there are relatively few studies in the available literature dedicated to the influence of osteopathic correction (OC) on the characteristics of these rhythms.Goal of research — to study the influence of OC on the rate characteristics of various rhythms of the human body.Materials and methods. 88 adult osteopathic patients aged from 18 to 81 years were examined, among them 30 men and 58 women. All patients received general osteopathic examination. The rate of the cranial rhythm (RCR), respiratory rate (RR) heart rate (HR), the mobility of the nervous processes (MNP) and the connective tissue mobility (CTM) were assessed before and after the OC session.Results. Since age varied greatly in the examined group, a correlation analysis of age-related changes of the assessed rhythms was carried out. Only the CTM correlated with age (r=–0,28; p<0,05) in a statistically significant way. The rank dispersion analysis of Kruskal–Wallis also showed statistically significant difference in this indicator in different age groups (p=0,043). With the increase of years, the CTM decreases gradually. After the OC, the CTM, increased in a statistically significant way (p<0,0001). The RCR varied from 5 to 12 cycles/min in the examined group, which corresponded to the norm. After the OC, the RCR has increased in a statistically significant way (p<0,0001), the MNP has also increased (p<0,0001). The initial heart rate in the subjects varied from 56 to 94 beats/min, and in 15 % it exceeded the norm. After the OC the heart rate corresponded to the norm in all patients. The heart rate and the respiratory rate significantly decreased after the OC (р<0,0001).Conclusion. The described biorhythm changes after the OC session may be indicative of the improvement of the nervous regulation, of the normalization of the autonomic balance, of the improvement of the biomechanical properties of body tissues and of the increase of their mobility. The assessed parameters can be measured quickly without any additional equipment and can be used in order to study the results of the OC.

scholarly journals Assessing the biomechanical properties of the porcine crystalline lens as a function of intraocular pressure with optical coherence elastography

2018 ◽  
Vol 9 (12) ◽  
pp. 6455 ◽  
Author(s):  
Chen Wu ◽  
Salavat R. Aglyamov ◽  
Zhaolong Han ◽  
Manmohan Singh ◽  
Chih-Hao Liu ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Crystalline Lens ◽  
Biomechanical Properties ◽  
Optical Coherence

scholarly journals Root Traits and Biomechanical Properties of Three Tropical Pioneer Tree Species for Forest Restoration in Landslide Areas

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 179 ◽  
Author(s):  
Lee ◽  
Chu ◽  
Lin ◽  
Kung ◽  
Lin ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Tree Species ◽  
Young's Modulus ◽  
Root Traits ◽  
Biomechanical Properties ◽  
Pioneer Species ◽  
Root Tensile Strength ◽  
Pioneer Tree ◽  
Macaranga Tanarius

Frequent earthquakes, monsoon torrential rains and typhoons cause severe landslides and soil erosion in Taiwan. Hibiscus taiwanensis, Macaranga tanarius, and Mallotus paniculatus are major pioneer tree species appearing on landslide-scarred areas. Thus, these species can be used to restore the self-sustaining native vegetation on forest landslides, to control erosion, and to stabilize slope. However, their growth performance, root traits and biomechanical properties have not been well characterized. In this study, root system and root traits were investigated using the excavation method, and biomechanical tests were performed to determine the uprooting resistance, root tensile strength and Young’s modulus of 1-year-old Hibiscus taiwanensis, Macaranga tanarius, and Mallotus paniculatus seedlings. The results reveal that relative to H. taiwanensis, M. tanarius and M. paniculatus seedlings had significantly larger root collar diameter, longer taproot length, higher root biomass, higher root density, higher root length density, heavier root mass, larger external root surface area, higher root tissue density, larger root volume, longer total root length, and a higher root tip number. Additionally, the height of M. paniculatus seedlings was significantly higher than those of H. taiwanensis and M. tanarius. Furthermore, the uprooting resistance and root tensile strength of M. paniculatus seedlings was significantly higher than those of H. taiwanensis and M. tanarius. Young’s modulus of M. paniculatus and M. tanarius seedlings was also significantly higher than that of H. taiwanensis. These growth characteristics and biomechanical properties demonstrate M. paniculatus and M. tanarius are superior than H. taiwanensis, considering growth performance, root anchorage capability, tensile strength and Young’s modulus. Taken as a whole, the rank order for species selection of these pioneer species for reforestation comes as: M. paniculatus M. tanarius H. taiwanensis. These results, along with knowledge on vegetation dynamics following landslides, allow us to better evaluate the effect of selective removal management of pioneer species on the resilience and sustainability of landslides.

Characterization of biomechanical properties of crystalline lens using Brillouin microscopy and optical coherence elastography

2020 ◽  
Author(s):  
Yogeshwari Ambekar ◽  
Manmohan Singh ◽  
Jitao Zhang ◽  
Achuth Nair ◽  
Salavat R. Aglyamov ◽  
...  
Keyword(s):  
Crystalline Lens ◽  
Biomechanical Properties ◽  
Optical Coherence

scholarly journals Role of Corneal Epithelium in Riboflavin/Ultraviolet-A Mediated Corneal Cross-Linking Treatment in Rabbit Eyes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Xiangchen Tao ◽  
Haiqun Yu ◽  
Yong Zhang ◽  
Zhiwei Li ◽  
Vishal Jhanji ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Corneal Epithelium ◽  
Young's Modulus ◽  
Biomechanical Properties ◽  
Cross Linking ◽  
Control Group ◽  
Ultraviolet A ◽  
Uva Irradiation ◽  
Maximal Stress

Purpose. To evaluate the role of corneal epithelium in riboflavin/ultraviolet-A (UVA) mediated corneal collagen cross-linking treatment.Methods. Fifty New Zealand rabbits were divided into 5 groups: UVA treatment with or without corneal epithelium, UVA+riboflavin treatment with or without corneal epithelium, and control without any treatment. All rabbits were sacrificed after irradiation and subsequently 4 mm × 10 mm corneal strips were harvested for biomechanical evaluation.Results. UVA irradiation alone did not enhance the maximal stress and Young’s modulus of corneal specimens with (3.15 ± 0.56 mpa, 1.00 ± 0.09 mpa) or without (3.53 ± 0.85 mpa, 0.94 ± 0.21 mpa) the corneal epithelium, compared to specimens in the control group (4.30 ± 0.68 mpa, 1.03 ± 0.24 mpa). However, UVA irradiation combined with riboflavin significantly increased the maximal stress and Young’s modulus of corneal specimens with (5.27 ± 1.09 mpa, 1.23 ± 0.23 mpa,P<0.05) or without (7.16 ± 1.88 mpa, 1.42 ± 0.16 mpa,P<0.05) corneal epithelium when compared to the control group. The maximal stress and Young’s modulus of cornea in UVA+riboflavin and “epithelium-off” group were 35.9% and 15.4% higher compared to the UVA+riboflavin and “epithelium-on” group, respectively (P<0.05).Conclusions. Our study shows that UVA+riboflavin treatment significantly affects the biomechanical properties of the cornea with and without epithelial removal. However, corneas without epithelium seem to benefit more compared to corneas with the epithelium.

scholarly journals Comparison of Riboflavin/Ultraviolet-A Cross-Linking in Porcine, Rabbit, and Human Sclera

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yali Zhang ◽  
Zhiwei Li ◽  
Lei Liu ◽  
Xuguang Han ◽  
Xiaomin Zhao ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Ultimate Stress ◽  
Cross Linking ◽  
Ultraviolet A ◽  
Rabbit Eye ◽  
Before And After ◽  
Biomechanical Parameters

Purpose. To compare the biomechanical properties of porcine, rabbit, and human sclera before and after riboflavin/ultraviolet-A (UVA) collagen cross-linking (CXL).Methods. Eight rabbits, 8 porcine eyeballs, and 8 human eyeballs were included. One rabbit eye and half of each bisected human and porcine eyeball were treated with riboflavin/UVA CXL. Untreated fellow rabbit eyes and eyeball halves served as controls. A 10 mm × 20 mm scleral band was harvested from each specimen. From this band, two 3.5 mm × 15.0 mm strips were prepared for biomechanical testing. The biomechanical parameters were ultimate stress, stress and Young’s modulus.Results. Values of stress, and Young’s modulus showed that human sclera was 4 times stiffer than porcine sclera and 3 times stiffer than rabbit sclera. In rabbit sclera, both the stress and Young’s modulus were significantly increased by CXL (P<0.05). In porcine sclera, only the ultimate stress was significantly increased by CXL (P<0.05). The biomechanical properties of human sclera were not statistically affected by CXL (P>0.05).Conclusions. Human sclera has higher biomechanical stiffness than porcine and rabbit sclera. With the same irradiation dose, riboflavin/UVA CXL increases the biomechanical stiffness of rabbit sclera but not porcine or human sclera.

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