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1.
Article in English | MEDLINE | ID: mdl-39093341

ABSTRACT

Overdose deaths from prescription opioids remain elevated, and policymakers seek solutions to curb opioid misuse. Recent proposals call for price-based solutions, such as opioid taxes and removal of opioids from insurance formularies. However, there is limited evidence on how opioid consumption responds to price stimuli. This study addresses that gap by estimating the effects of prices on the utilization of opioids, as well as other prescription painkillers. I use nationally representative individual-level data on prescription drug purchases and exploit the introduction of Medicare Part D in 2006 as an exogenous change in out-of-pocket drug prices. I find that new users have a relatively high price elasticity of demand for prescription opioids, and that consumers treat over-the-counter painkillers as substitutes for prescription painkillers. My results suggest that increasing out-of-pocket prices of opioids, through formulary design or taxes, may be effective in reducing new opioid use.

2.
Jpn J Ophthalmol ; 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39088115

ABSTRACT

PURPOSE: This study evaluated the role of shear wave elastography imaging (SWEΙ) in uveal melanomas and the associations between SWEI and clinical and hemodynamic findings. STUDY DESIGN: Prospective, clinical study METHODS: Twelve patients with uveal melanomas, scheduled to undergo Ru-106 brachytherapy, were prospectively recruited from the Department of Ophthalmology of the University Hospital of Heraklion (September-December 2022). B-mode, hemodynamic and SWEI ultrasonography examinations were performed with the HiScan (OPTIKON 2000) and the LOGIQ E9 (GE Healthcare) sonographic systems, respectively. Differences in SWEI scores (kPa) between tumor (TS) and adjacent non-affected choroid (CS), as well as between TS and orbital fat (FS) were examined. Correlations between SWEI and intra-tumoral hemodynamic parameters, including peak systolic and end diastolic velocities and resistivity index (RI) were also examined. RESULTS: TS was significantly correlated with intra-tumoral RI (Pearson's bivariate correlation coefficient 0.681, p=0.015) and with maximal tumor height (Pearson's bivariate correlation coefficient 0.620, p=0.031). TS was significantly higher than both FS and CS scores (paired-samples t-test, p=0.003 and p=0.006, respectively). CONCLUSIONS: SWEI score is applicable as a quantitative biomechanical marker in the assessment of choroidal melanoma. Choroidal melanomas are stiffer than both adjacent choroid and orbital fat. Moreover, choroidal melanomas with higher RI as well as those with higher apical elevations display higher SWEI scores.

3.
Skin Res Technol ; 30(8): e13861, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39096185

ABSTRACT

BACKGROUND: Skin conditions in patients with lymphedema have been identified according to changes in skin mechanical properties. The skin elasticity meter is a non-invasive tool for measuring the mechanical properties of the skin; however, its potential use in patients with lymphedema has received little attention. This review aimed to provide an overview of studies measuring the skin mechanical properties of patients with lymphedema using a skin elasticity meter. MATERIALS AND METHODS: Search terms and synonyms related to lymphedema and skin mechanical property measurement using a skin elasticity meter were identified, and electronic databases containing articles in English were searched. RESULTS: A total of 621 articles were retrieved, and four articles were analyzed after screening. Despite this research subject receiving increasing attention, no consensus has been reached regarding the best methods. CONCLUSION: Measurement methods are expected to be standardized in the future to elucidate the skin mechanical properties of patients with lymphedema.


Subject(s)
Elasticity , Lymphedema , Skin Physiological Phenomena , Humans , Lymphedema/physiopathology , Elasticity/physiology , Skin/physiopathology , Skin/diagnostic imaging
4.
Comput Biol Med ; 179: 108916, 2024 Jul 24.
Article in English | MEDLINE | ID: mdl-39053330

ABSTRACT

The present work studies the variation in the nature of Rayleigh waves due to change in age, gender and morphological region of human skin tissue in the context of three-phase-lag (TPL) nonlocal thermoelastic theory. The secular equations are derived using the stress free, thermally insulated or isothermal boundary conditions. These secular equations are solved numerically and two significant modes of Rayleigh wave are noted to propagate simultaneously. The phase speeds, attenuation coefficients and path of the particle motion for both modes are presented graphically. These results are compared for different age, gender and morphological region of the source skin tissue. We have observed that the phase speeds increase with the increases of stiffness of the skin and vice versa. Certain specific angular frequencies and phase speeds are obtained which can be used for the detection and thermal therapy of skin disorders. Some published results are recovered as special cases to validate the current results.

5.
Regen Biomater ; 11: rbae069, 2024.
Article in English | MEDLINE | ID: mdl-39055305

ABSTRACT

As we age, our skin loses elasticity and wrinkles form. To prevent this, most people try to improve skin wrinkles by performing procedures such as fillers, and absorbable lifting threads. Another way to solve this structural problem is to use an elastic thread. Although elastic sutures made of polymer materials (such as silicone) are widely used, data regarding their properties and potential effectiveness are lacking. This study aimed to investigate the effects of inserting non-absorbable elastic threads, with different manufacturing requirements and methods, on the skin and subcutaneous tissue. In this study, non-absorbable elastic threads ELATENS and Elasticum using different manufacturing methods were compared. Each thread was transplanted into the subcutaneous layer of the back of a rat to induce wrinkles. After inducing wrinkles in the skin of rat, the degree of skin maintenance by each thread and the thickness of the capsule formed around the suture were measured. Through ex-vivo experiments on each thread, the fixation force in the tissue was confirmed. In a comparison of inflammatory response and collagen formation through histological analysis, it was confirmed that there was no significant difference from the equivalent comparative product. In conclusion, the degree of encapsulation between tissues and collagen fiber formation for improving skin wrinkles was superior in elastic threads compared to non-elastic threads. It is believed that this provides certain elasticity to the skin layer and can induce cell influx to improve wrinkles.

6.
Int J Biol Macromol ; 276(Pt 2): 133983, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39029850

ABSTRACT

This study examined the influence of nanomaterials (NMs) on the organization of membrane lipids and the resulting morphological changes. The cell plasma membrane is heterogeneous, featuring specialized lipid domains in the liquid-ordered (Lo) phase surrounded by regions in the liquid-disordered (Ld) phase. We utilized model membranes composed of various lipids and lipid mixtures in different phase states to investigate the interactions between the NMs and membrane lipids. Specifically, we explored the interactions of pure chitosan (CS) and CS-modified nanocomposites (NCs) with ZnO, CuO, and SiO2 with four lipid mixtures: egg-phosphatidylcholine (EggPC), egg-sphingomyelin/cholesterol (EggSM/Chol), EggPC/Chol, and EggPC/EggSM/Chol, which represent the coexistence of Ld, Lo, and Ld/Lo, respectively. The data show that CS NMs increase the membrane lipid order at glycerol level probed by Laurdan spectroscopy. Additionally, the interaction of CS-based NMs with membranes leads to an increase in bending elasticity modulus, zeta potential, and vesicle size. The lipid order changes are most significant in the highly fluid Ld phase, followed by the Lo/Ld coexistence phase, and are less pronounced in the tightly packed Lo phase. CS NMs induced egg PC vesicle adhesion, fusion, and shrinking. In heterogeneous Lo/Ld membranes, inward invaginations and vesicle shrinking via the Ld phase were observed. These findings highlight mechanisms involved in CS NM-lipid interactions in membranes that mimic plasma membrane heterogeneity.

7.
Abdom Radiol (NY) ; 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-38990302

ABSTRACT

PURPOSE: To assess the feasibility and performance of MR elastography (MRE) for quantifying liver fibrosis in patients with and without hepatic iron overload. METHODS: This retrospective single-center study analyzed 139 patients who underwent liver MRI at 3 Tesla including MRE (2D spin-echo EPI sequence) and R2* mapping for liver iron content (LIC) estimation. MRE feasibility and diagnostic performance between patients with normal and elevated LIC were compared. RESULTS: Patients with elevated LIC (21%) had significantly higher MRE failure rates (24.1% vs. 3.6%, p < 0.001) compared to patients with normal LIC (79%). For those with only insignificant to mild iron overload (LIC < 5.4 mg/g; 17%), MRE failure rate did not differ significantly from patients without iron overload (8.3% vs. 3.6%, p = 0.315). R2* predicted MRE failure with fair accuracy at a threshold of R2* ≥ 269 s-1 (LIC of approximately 4.6 mg/g). MRE showed good diagnostic performance for detecting significant (≥ F2) and severe fibrosis (≥ F3) in patients without (AUC 0.835 and 0.900) and with iron overload (AUC 0.818 and 0.889) without significant difference between the cohorts (p = 0.884 and p = 0.913). For detecting cirrhosis MRE showed an excellent diagnostic performance in both groups (AUC 0.944 and 1.000, p = 0.009). CONCLUSION: Spin-echo EPI MRE at 3 Tesla is feasible in patients with mild iron overload with good to excellent performance for detecting hepatic fibrosis with a failure rate comparable to patients without iron overload.

8.
Philos Trans A Math Phys Eng Sci ; 382(2277): 20240115, 2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39005011

ABSTRACT

The paper investigates a problem concerning the equilibrium of a solid body containing a thin rigid inclusion and a crack. It is assumed that the body is hyperelastic, therefore, it is described within the framework of finite strain theory. One of the peculiarities of this problem is a global injectivity constraint, which prevents the body, the crack faces and the inclusion from both mutual and self penetration. First, the paper deals with the differential formulation of the problem. Next, we consider energy minimization, showing that the latter provides the weak formulation of the former. Finally, the existence of the weak solution is demonstrated through the use of the variational technique.This article is part of the theme issue 'Non-smooth variational problems with applications in mechanics'.

9.
Philos Trans A Math Phys Eng Sci ; 382(2277): 20230308, 2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39005023

ABSTRACT

As the size of a layered structure scales down, the adhesive layer thickness correspondingly decreases from macro- to micro-scale. The influence of the material microstructure of the adhesive becomes more pronounced, and possible size effect phenomena can appear. This paper describes the mechanical behaviour of composites made of two solids, bonded together by a thin layer, in the framework of strain gradient and micropolar elasticity. The adhesive layer is assumed to have the same stiffness properties as the adherents. By means of the asymptotic methods, the contact laws are derived at order 0 and order 1. These conditions represent a formal generalization of the hard elastic interface conditions. A simple benchmark equilibrium problem (a three-layer composite micro-bar subjected to an axial load) is developed to numerically assess the asymptotic model. Size effects and non-local phenomena, owing to high strain concentrations at the edges, are highlighted. The example proves the efficiency of the proposed approach in designing micro-scale-layered devices.This article is part of the theme issue 'Non-smooth variational problems with applications in mechanics'.

10.
Nano Lett ; 24(28): 8717-8722, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-38976791

ABSTRACT

Crystalline monolayers prevalent in nature and technology possess elusive elastic properties with important implications in fundamental physics, biology, and nanotechnology. Leveraging the recently discovered shape transitions of oil-in-water emulsion droplets, upon which these droplets adopt cylindrical shapes and elongate, we investigate the elastic characteristics of the crystalline monolayers covering their interfaces. To unravel the conditions governing Euler buckling and Brazier kink formation in these cylindrical tubular interfacial crystals, we strain the elongating cylindrical droplets within confining microfluidic wells. Our experiments unveil a nonclassical relation between the Young's modulus and the bending modulus of these crystals. Intriguingly, this relation varies with the radius of the cylindrical crystal, presenting a nonclassical mechanism for tuning of elasticity in nanotechnology applications.

11.
Int J Gen Med ; 17: 3015-3025, 2024.
Article in English | MEDLINE | ID: mdl-39006910

ABSTRACT

Background: Thyroid disorders, relatively common diseases of the endocrine system, have risen gradually in recent years. Early detection and accurate diagnosis of thyroid cancer hold exceptional importance. This study aimed to determine the efficacy of a modified TI-RADS and BRAFV600E mutation testing for thyroid cancer (PTC) diagnosis. Methods: Ninety five thyroid nodules (48 benign and 47 malignant) from 81 patients were examined using Kwak Thyroid Imaging Reporting and Data System (TI-RADS) were subjected to shear wave elasticity (SWE), BRAFV600E genotyping and fine needle aspiration (FNA) cytology. Results: The modified TI-RADS exhibited superior diagnostic accuracy compared to TI-RADS in differentiating benign nodules from malignant thyroid nodules. Moreover, the AUC of modified TI-RADS in conjunction with BRAFV600E was the highest at 95% CI (0.898-0.992, p=0.003), surpassing other diagnostic methods in enhanced sensitivity and maintaining high specificity. Conclusion: The diagnostic efficiency of this combination surpassed that of individual diagnostic methods.

12.
J Orthop Surg Res ; 19(1): 394, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38978119

ABSTRACT

INTRODUCTION: Fu's subcutaneous needling (FSN) is a new type of acupuncture that uses subcutaneous tissue to oscillate from side to side to improve muscle pathology status and can be effective in treating Knee osteoarthritis. Nonetheless, whether the clinical effect is similar to that of most commonly used drugs is unclear. Thus, this study aims to determine the pain-relieving effect and improvement in the joint function of the FSN therapy by comparing it with that of a positive control drug (celecoxib). Furthermore, this clinical trial also aims to evaluate the effect of FSN on gait and lower limb muscle flexibility, which can further explore the scientific mechanisms of the FSN therapy. METHODS AND ANALYSIS: This study is a randomized, parallel-controlled, single-center prospective clinical study that includes 60 participants, with an FSN group (n = 30) and a drug group (n = 30). The Fu's subcutaneous needling (FSN) group undergo the FSN therapy 3 times a week for 2 weeks, while the drug group receives 0.2 g/day oral celecoxib for 2 weeks, with a follow-up period of 4 weeks after the completion of treatment. The primary outcome is the difference in the visual analog scale score after 2 weeks of treatment compared with baseline. The Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, joint active range of motion test, three-dimensional gait analysis, and shear wave elastic imaging technology analysis in lower limb muscles are also performed to demonstrate clinical efficacy. ETHICS AND DISSEMINATION: The trial is performed following the Declaration of Helsinki. The study protocol and consent form have been approved by the Ethics Committee of Guangdong Provincial Hospital of Chinese Medicine. All patients will give informed consent before participation and the trial is initiated after approval. The results of this trial will be disseminated through publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT06328153.


Subject(s)
Acupuncture Therapy , Osteoarthritis, Knee , Humans , Osteoarthritis, Knee/therapy , Acupuncture Therapy/methods , Prospective Studies , Female , Male , Aged , Treatment Outcome , Biomechanical Phenomena , Middle Aged , Celecoxib/administration & dosage , Range of Motion, Articular , Randomized Controlled Trials as Topic , Gait
13.
Quant Imaging Med Surg ; 14(7): 4987-4997, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-39022243

ABSTRACT

Background: Varicocele is a major correctable cause of male infertility. Shear wave elastography (SWE) represents a valuable approach for assessing spermatogenesis in infertile men; however, its application in infertile men with varicocele remains unreported in the literature to date. The objective of this study was to investigate the correlation between testicular stiffness and spermatogenesis in individuals with varicocele. Methods: A total of 568 participants with left-side varicocele and 475 age-matched healthy controls were enrolled. The mean, left, and right testicular volumes (Volume-mean, Volume-L, and Volume-R), the mean elastic modulus of bilateral, left, and right testes (Emean, Emean-L, and Emean-R); the maximum elastic modulus of bilateral, left, and right testes (Emax, Emax-L, and Emax-R); the minimum elastic modulus of bilateral, left, and right testes (Emin, Emin-L, and Emin-R) were calculated. Results: Receiver operating characteristic (ROC) curves for Volume-R and Emax were constructed to identify participants with sperm concentrations below 5 million/mL. The areas under the ROC curves (AUCs) were 0.801 and 0.775, respectively. Combining these 2 markers improved their diagnostic value with an AUC of 0.820 and sensitivity and specificity of 94.6% and 59.8% [95% confidence interval (CI): 0.772-0.867, P<0.01], respectively. A total of 69 participants underwent microsurgical varicocelectomy (including 42 cases with improved semen results and 27 without). The ROC curves of Emax-L and Volume-L were constructed for the differential diagnosis between the improved and unimproved groups; the AUCs were 0.723 and 0.855, respectively. Combining these 2 markers improved their diagnostic value with an AUC of 0.867 (95% CI: 0.772-0.961, P<0.01) and sensitivity and specificity of 81.5% and 81.0%, respectively. Conclusions: Our findings suggest that SWE can be used for varicocele to assess testicular parenchyma damage and Volume-L combined with Emax-L offers a more accurate method for predicting semen parameter improvement after microscopic subinguinal varicocelectomy in men with varicocele.

14.
Quant Imaging Med Surg ; 14(7): 4815-4824, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-39022240

ABSTRACT

Background: Intraplaque neovascularization (IPN) is a biomarker for vulnerable atherosclerotic plaques and can be effectively visualized via contrast-enhanced ultrasound (CEUS). Plaque elasticity is influenced by elements such as lipid core and fibrosis and can be quantitatively assessed on shear wave elastography (SWE). Studies combining the use of CEUS and SWE for the assessment of stroke risk are currently lacking. Our study thus aimed to determine the predictive value of IPN combined with plaque elasticity among patients with asymptomatic carotid plaque. Methods: Consecutive patients with mild carotid stenosis who underwent CEUS and SWE were retrospectively analyzed. IPN was graded according to the presence and location of microbubbles within the plaque, while plaque elasticity was measured in terms of mean shear wave velocity (SWV). All patients were followed up for 6 months to monitor the development of ischemic stroke. The predictive values of IPN and SWV, individually and in combination, were assessed. Results: A total of 121 patients were included, of whom 95 (78.5%) were male. The mean age was 63.1±10.7 years. Both grade 2 IPN [hazard ratio (HR) =2.37, 95% confidence interval (CI): 1.58-9.65; P=0.039] and SWV (HR =0.43, 95% CI: 0.20-0.95; P=0.038) were independently associated with future ischemic stroke events. The combined model demonstrated a significantly better predictive performance (HR =3.243, 95% CI: 1.87-6.17; P=0.027). Conclusions: The combination of IPN and SWV demonstrated significantly better predictive value for the risk of stroke. Our combined model thereby has the potential to guide the clinical stratification and management of patients with asymptomatic mild carotid stenosis.

15.
Methods Enzymol ; 701: 175-236, 2024.
Article in English | MEDLINE | ID: mdl-39025572

ABSTRACT

Biomembranes and vesicles cover a wide range of length scales. Indeed, small nanovesicles have a diameter of a few tens of nanometers whereas giant vesicles can have diameters up to hundreds of micrometers. The remodeling of giant vesicles on the micron scale can be observed by light microscopy and understood by the theory of curvature elasticity, which represents a top-down approach. The theory predicts the formation of multispherical shapes as recently observed experimentally. On the nanometer scale, much insight has been obtained via coarse-grained molecular dynamics simulations of nanovesicles, which provides a bottom-up approach based on the lipid numbers assembled in the two bilayer leaflets and the resulting leaflet tensions. The remodeling processes discussed here include the shape transformations of vesicles, their morphological responses to the adhesion of condensate droplets, the instabilities of lipid bilayers and nanovesicles, as well as the topological transformations of vesicles by membrane fission and fusion. The latter processes determine the complex topology of the endoplasmic reticulum.


Subject(s)
Lipid Bilayers , Molecular Dynamics Simulation , Lipid Bilayers/chemistry , Cell Membrane/chemistry , Cell Membrane/metabolism , Membrane Fusion/physiology , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum/ultrastructure , Animals , Humans
16.
Sci Rep ; 14(1): 16189, 2024 Jul 13.
Article in English | MEDLINE | ID: mdl-39003291

ABSTRACT

Concrete, the construction industry's most utilized construction material, has transformed the environment and the modern built-up lifestyle. Although concrete is a first-rate supplier to the carbon footprint, it is imperative for buildings to display sustainable characteristics. Scholars have explored techniques to lessen the carbon footprint and the way to put into effect strategic waste control plans in which waste is reused. This study explores the dual benefits wherein concrete ingredients are replaced through abandoned waste which reduces the unwanted waste materials that have a substantial carbon footprint and thus results in the recycling of waste as part of a sustainable economic system. In this study, timber ash is utilized as a partial substitute for sand and cement, crumb rubber and waste glass as a partial substitute for sand, recycled concrete, and waste glass as a substitute for gravel. Characteristics studies were done to check the influence of each waste replacement on the modulus of elasticity of concrete. More than sixty-five combinations of waste have been examined to attain the modulus of elasticity of concrete. A total of about 200 concrete cylinders were cast to provide at least three cylinders for each generated data point. Three different ASTM standards were utilized to determine the modulus of elasticity of each mix. Four mixes comprising of the combination of two waste materials and two mixes comprising of the combination of three waste materials replacing natural materials were determined to exhibit an equal or superior modulus of elasticity of the control mix of 25 GPa.

17.
Exp Eye Res ; 246: 109992, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38972445

ABSTRACT

Previous studies have shown that pharmaceutical agents such as lipoic acid have the ability to soften the lens, presenting a promising avenue for treating presbyopia. One obstacle encountered in the preclinical stage of such agents is the need for precise measurements of lens elasticity in experimental models. This study aimed to evaluate the effects of 25-hydroxycholesterol, lipoic acid, and obeticholic acid on the viscoelastic properties of mouse lenses using a custom-built elastometer system. Data were acquired on lenses from C57BL/6J female mice from two age groups: young (age: 8-10 weeks) and old (age: 32-43 weeks). OD lenses were used as the control and OS lenses were treated. Control lenses were immersed in Dulbecco's Modified Eagle Medium (DMEM) and treatment lenses were immersed in a compound solution containing 25-hydroxycholesterol (5 young and 5 old), lipoic acid at 2.35 mM (5 young and 5 old), lipoic acid at 0.66 mM (5 old), or obeticholic acid (5 old) at 37 °C for 18 h. After treatment, the mouse lenses were placed in a DMEM-filled chamber within a custom-built elastometer system that recorded the load and lens shape as the lens was compressed by 600 µm at a speed of 50 µm/s. The load was continuously recorded during compression and during stress-relaxation. The compression phase was fit with a linear function to quantify lens stiffness. The stress-relaxation phase was fit with a 3-term exponential relaxation model providing relaxation time constants (t1, t2, t3), and equilibrium load. The lens stiffness, time constants and equilibrium load were compared for the control and treated groups. Results revealed an increase in stiffness with age for the control group (young: 1.16 ± 0.11 g/mm, old: 1.29 ± 0.14 g/mm) and relaxation time constants decreased with age (young: t1 = 221.9 ± 29.0 s, t2 = 24.7 ± 3.8 s, t3 = 3.12 ± 0.87 s, old: t1 = 183.0 ± 22.0 s, t2 = 20.6 ± 2.6 s and t3 = 2.24 ± 0.43 s). Among the compounds tested, only 25-hydroxycholesterol produced statistically significant changes in the lens stiffness, relaxation time constants, and equilibrium load. In conclusion, older mouse lenses are stiffer and less viscous than young mouse lenses. Notably, no significant change in lens stiffness was observed following treatment with lipoic acid, contrary to previous findings.

18.
Int J Biol Macromol ; 275(Pt 1): 133600, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38960237

ABSTRACT

In situ forming poly(dimethylaminoethyl methacrylate-co-glycidylmethacrylate)/Chitosan, P(DMAEMA-co-GMA)/Chitosan, (PDG/CS) cryobeads based on "dropwise freezing into cryogenic liquid method" combined with "blending with polymer method" are promising for applications due to their pH-responsiveness and stability under physiological conditions. Based on classical contact mechanics, Hertzian elasticity of semi-interpenetrated network (semi-IPN) cryobeads was analyzed to examine whether there is a direct correlation between elastic properties of single particle and its macroscopic behavior. A one-step procedure has been proposed to design chitosan-interpenetrated cryobeads with a cationic nature via combination of structural properties as well as functionality of chitosan containing primary and secondary hydroxyl and amino groups. The study is focused on characterization of network formation kinetics in different shapes and how different production variables affect the elasticity/swelling performance of cross-linked system. The elastic properties of semi-IPN cryobeads were improved by both adding chitosan to copolymer PDG structure and lowering the gelation temperature to cryogelation conditions. The results obtained highlighted the importance of composition to modulate elasticity, the influence of preparation temperature and shape of cryobeads on their elasticity. Findings regarding the topography-dependent local elastic properties of chitosan-incorporated semi-IPN gels offer possibilities for modulating the behavior of chitosan-based soft materials.

19.
Heliyon ; 10(11): e32616, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38961961

ABSTRACT

The study aimed to evaluate the impact of varying modulus of elasticity (MOE) values of dental implants on the deformation and von Mises stress distribution in implant systems and peri-implant bone tissues under dynamic cyclic loading. The implant-bone interface was characterised as frictional contact, and the initial stress was induced using the interference fit method to effectively develop a finite element model for an immediately loaded implant-supported denture. Using the Ansys Workbench 2021 R2 software, an analysis was conducted to examine the deformation and von Mises stress experienced by the implant-supported dentures, peri-implant bone tissue, and implants under dynamic loading across three simulated masticatory cycles. These findings were subsequently evaluated through a comparative analysis. The suprastructures showed varying degrees of maximum deformation across zirconia (Zr), titanium (Ti), low-MOE-Ti, and polyetheretherketone (PEEK) implant systems, registering values of 103.1 µm, 125.68 µm, 169.52 µm, and 844.06 µm, respectively. The Zr implant system demonstrated the lowest values for both maximum deformation and von Mises stress (14.96 µm, 86.71 MPa) in cortical bone. As the MOE increased, the maximum deformation in cancellous bone decreased. The PEEK implant system exhibited the highest maximum von Mises stress (59.12 MPa), whereas the Ti implant system exhibited the lowest stress (22.48 MPa). Elevating the MOE resulted in reductions in both maximum deformation and maximum von Mises stress experienced by the implant. Based on this research, adjusting the MOE of the implant emerged as a viable approach to effectively modify the biomechanical characteristics of the implant system. The Zr implant system demonstrated the least maximum von Mises stress and deformation, presenting a more favourable quality for preserving the stability of the implant-bone interface under immediate loading.

20.
Health SA ; 29: 2419, 2024.
Article in English | MEDLINE | ID: mdl-38962295

ABSTRACT

Background: Pro-inflammatory markers are linked with the development and progression of type 2 diabetes mellitus and arterial stiffening. Pulse Wave Velocity (PWV) and Augmentation Index (Aix) are non-invasive standard markers of arterial elasticity and predictors of cardiovascular mortality and morbidity. Aim: To investigate the effects of metformin alone and in combination with glimepiride on arterial elasticity, pro-inflammatory cytokines in black type 2 diabetes mellitus patients. Settings: Participants were enrolled from Sefako Makgatho Health Sciences University community, Gauteng, South Africa. Methods: PWV and Aix were measured using the AtCor SphygmoCor® system (AtCor Medical, Inc., Sydney, Australia). Cytokines levels were measured using Multiplexing with Bio-Plex Pro™ human inflammation panel I assay. Treatment naïve type 2 diabetes participants were divided into two groups: metformin (M) (n = 10) and metformin glimepiride (MS) (n = 14). The study participants were followed up at 4 and 8 months after treatment initiation. Results: In the M and MS, IL-1ß increased significantly at four months (58.19 ± 0.03 pg/ml, 58.35 ± 0.30 pg/ml) when compared to baseline (33.05 ± 18.56 pg/ml, 34.79 ± 18.77 pg/ml) then decreased significantly at eight months (29.25 ± 11.64 pg/ml, 32.54 ± 14.26 pg/ml) when compared to four months (58.19 ± 0.03 pg/ml, 58.35 ± 0.3 pg/ml) (p < 0.05). There were no significant changes in PWV, Aix, IL-1ra, IL-2, IL-6, IL-8, TNF-α and hs-CRP levels at both treatment intervals. Conclusion: Metformin alone or in combination with glimepiride did not improve arterial elasticity and did not reduce pro-inflammatory cytokines levels in T2DM black South African patients. Contribution: The context-based knowledge generated by the current study is expected to enhance the continuum of care for T2DM patients.

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