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1.
Nano Lett ; 24(28): 8717-8722, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-38976791

RESUMEN

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.

2.
Methods Enzymol ; 701: 175-236, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39025572

RESUMEN

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.


Asunto(s)
Membrana Dobles de Lípidos , Simulación de Dinámica Molecular , Membrana Dobles de Lípidos/química , Membrana Celular/química , Membrana Celular/metabolismo , Fusión de Membrana/fisiología , Retículo Endoplásmico/metabolismo , Retículo Endoplásmico/ultraestructura , Animales , Humanos
3.
Abdom Radiol (NY) ; 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38990302

RESUMEN

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.

4.
Philos Trans A Math Phys Eng Sci ; 382(2277): 20240115, 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39005011

RESUMEN

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'.

5.
Philos Trans A Math Phys Eng Sci ; 382(2277): 20230308, 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39005023

RESUMEN

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'.

6.
J Orthop Surg Res ; 19(1): 394, 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38978119

RESUMEN

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.


Asunto(s)
Terapia por Acupuntura , Osteoartritis de la Rodilla , Humanos , Osteoartritis de la Rodilla/terapia , Terapia por Acupuntura/métodos , Estudios Prospectivos , Femenino , Masculino , Anciano , Resultado del Tratamiento , Fenómenos Biomecánicos , Persona de Mediana Edad , Celecoxib/administración & dosificación , Rango del Movimiento Articular , Ensayos Clínicos Controlados Aleatorios como Asunto , Marcha
7.
Sci Rep ; 14(1): 16189, 2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-39003291

RESUMEN

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.

8.
Int J Gen Med ; 17: 3015-3025, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39006910

RESUMEN

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.

9.
Exp Eye Res ; 246: 109992, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38972445

RESUMEN

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.

10.
Heliyon ; 10(11): e32616, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38961961

RESUMEN

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.

11.
Health SA ; 29: 2419, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38962295

RESUMEN

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.

12.
Int J Biol Macromol ; 275(Pt 1): 133600, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38960237

RESUMEN

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.

13.
Adv Colloid Interface Sci ; 331: 103165, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38964197

RESUMEN

Colloid particles (CP, 10-8-10-6 m = 10-1000 nm) are used as models for atom scale processes, such as crystallization since the process is experimentally observable. Packing of atoms in crystals resemble mono-, bi-, and trimodal packing of noncharged hard spheres (particles). When the size of one particle exceeds the two others an excluded volume consisting of small particles is created around large particles. This is also the case when colloid particles are dispersed in water. The formation of an excluded volume does not require attraction forces, but it is enforced by the presence of dissolved primary (cations) and secondary (protons of surface hydroxyls) potential determining ions. The outcome is an interfacial solid-liquid charge. This excluded volume, denoted Stern layer is characterized by the surface potential and charge density. Charge neutrality is identified by point of zero charge (pHpzc and pcpzc). Outside Stern layer another excluded volume is formed of loosely bound counterions which interact with Stern layer. The extent of this diffuse layer is given by inverse Debye length and effective ζ-potential. The overall balance between attractive and repulsive energies is provided by Derjaguin-Landau-Veerwey-Overbeek (DLVO) model. Charge neutrality is identified at isoelectric point (pHiep and pciep). The dependence of viscosity and yield stress on shear rate may be modeled by von Smoluchowski's volumetric collision frequency multiplied by some total interaction energy given by DLVO model. Equilibrium and dynamic models for settling and enforced particle movement (viscosity) are presented. Both compressive yield stress (sedimentation) and cohesive energy (viscoelasticity) are characterized by power law exponents of volume fraction. The transition of disperse suspensions (sols) to spanning clusters (gels) is identified by oscillatory rheology. The slope of linear plots of logarithmic storage (G´) and loss (G") moduli against logarithm of frequency or logarithm of volume fraction provide power law exponents from the slopes. These exponents relate to percolation and fractal dimensions characterizing the particle network. Moreover, it identifies the structure formation process either as diffusion limited cluster-cluster (DLCCA) or as reaction limited cluster-cluster (RLCCA) aggregation.

14.
Quant Imaging Med Surg ; 14(7): 4987-4997, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-39022243

RESUMEN

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.

15.
Quant Imaging Med Surg ; 14(7): 4815-4824, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-39022240

RESUMEN

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.

16.
Heliyon ; 10(13): e33540, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39027519

RESUMEN

The main objectives of this study are to estimate the biased technical progress in China considering heterogeneity in human capital and labor force, examine how this heterogeneity quantitatively impacts the elasticity of substitution and biased technical progress compared to homogeneous labor assumptions, and compare the growth rates of human capital-augmenting and labor-augmenting technical progress. The estimation procedure involves a constrained Seemingly Unrelated Regression (SUR) using provincial-level panel data from 1985 to 2021. By comparing results with and without accounting for labor force heterogeneity and human capital, the analysis quantifies their impact on the estimated elasticity of substitution between factors and the magnitude and direction of technical bias. Results found that the elasticity of capital-labor (human capital) substitution is between 0.7 and 0.8, and the elements are generally complementary. Although it does not affect the overall trend of elasticity of substitution and biased technical progress, the heterogeneity of human capital and labor force has a quantitative impact on them. It means that the elasticity of substitution increased, and the biased technological progress decreased. Moreover, the growth rate of human capital-augmenting technical progress was significantly lower than that of labor-augmenting technological progress. This study estimates the biased technical progress in China, where the human capital and labor force are heterogeneous. The findings suggest that policymakers should prioritize human capital investments and technological upgrades in industries to rebalance China's technical progress and boost productivity growth.

17.
Nutr Res Pract ; 18(3): 357-371, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38854476

RESUMEN

BACKGROUND/OBJECTIVES: Collagen is commonly used in diverse forms as a functional component in skincare products. On the other hand, the effects of collagen on human skin are controversial. Dietary collagen hydrolysates from freshwater Pangasius hypophthalmus fish skin ameliorated photo-aged skin of hairless mice. This study conducted a randomized, double-blind, placebo-controlled clinical trial to determine if liquid fish collagen (Collagen-Tripep20™, Tripep20) as a drink strengthens skin health and quality. SUBJECTS/METHODS: In this clinical trial, 85 subjects aged 35-60 yrs were diagnosed with photo-aged skin. Eighty-five subjects were randomized to receive either Tripep20 (n = 44) or placebo (n = 41). Seventy-eight subjects fully participating for a 12-week period consumed 1,000 mg of Tripep20 (n = 41) or placebo (n = 37) in a 50-mL bottle as a daily drink. The intend-to-treat and per-protocol populations were 85 and 78, respectively. Skin hydration, wrinkles, and elasticity were assessed at 0 (baseline), 6, and 12 weeks during the study period. RESULTS: Skin hydration in the Tripep20 group was significantly higher from 6 weeks (P < 0.001) than the baseline. After 12 weeks, the Crow's-feet visual score and skin roughness (Ra, Rq, and Rmax) were significantly improved in the Tripep20 group than in the placebo group (P < 0.05). Consuming liquid collagen Tripep20 greatly enhanced skin elasticity (Gross R2, Net R5, and Biological elasticity R7) in 6 weeks compared to the placebo group. The Tripep20 group showed a significant increase in skin elasticity from the baseline after 6 and 12 weeks (P < 0.001). Neither abnormal symptoms nor adverse events were encountered during the study period in subjects ingesting Tripep20 or placebo. The changes in parameters related to hematology and clinical chemistry were within the normal ranges. CONCLUSION: Oral consumption of liquid collagen Tripep20 was safe and well-tolerated. The results of this study show that freshwater fish-derived liquid collagen Tripep20 can be used as a healthy functional food ingredient to improve skin moisturizing, anti-wrinkling, and elasticity in an aging population.

18.
Exploration (Beijing) ; 4(2): 20230057, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38855621

RESUMEN

3D graphene porous materials (3GPM), which have low density, large porosity, excellent compressibility, high conductivity, hold huge promise for a wide range of applications. Nevertheless, most 3GPM have brittle and weak network structures, which limits their widespread use. Therefore, the preparation of a robust and elastic graphene porous network is critical for the functionalization of 3GPM. Herein, the recent research of 3GPM with excellent mechanical properties are summarized and the focus is on the effect factors that affect the mechanical properties of 3GPM. Moreover, the applications of elastic 3GPM in various fields, such as adsorption, energy storage, solar steam generation, sensors, flexible electronics, and electromagnetic wave shielding are comprehensively reviewed. At last, the new challenges and perspective for fabrication and functionalization of robust and elastic 3GPM are outlined. It is expected that the perspective will inspire more new ideas in preparation and functionalization of 3GPM.

19.
Eur J Radiol Open ; 12: 100573, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38855720

RESUMEN

Purpose: Shear wave elastography (SWE), an ultrasonographic technique to measure the elasticity of mass lesions to evaluate breast mass. This study aimed to find out the cutoff values identifying breast malignancy using the mean elasticity (E-mean) and elasticity ratio (E-ratio) of breast masses. Methods: This retrospective study included women underwent SWE and US-guided biopsy of breast masses. During conventional US, the SWE mode was also performed, determining elasticity measurements, E-mean and E-ratio. Histopathological reports were obtained to identify mass status. The optimal and alternative cutoff values for E-mean and E-ratio to determine malignancy were assessed by receiver operating characteristic (ROC) curve analysis and Youden's index score. Results: Among 147 benign and 93 malignant masses, the median of E-means were 26.20 (IQR 15.70-56.60) and 141.60 (IQR 119.80-154.60) kPa and the median E-ratios were 3.11 (IQR 1.83-5.23) and 9.24 (IQR 6.76-12.44), respectively. Using Youden's index, the optimal cutoff values for E-mean and E-ratio were 90.35 and 5.89, with sensitivity of 87.1 % and 82.8 %, specificity of 89.1 % and 83.7 %, positive predictive value (PPV) of 83.5 % and 76.2 %, negative predictive value (NPV) of 91.6 % and 88.5 %, positive likelihood ratio (LR+) of 8.00 and 5.07, and negative likelihood ratio (LR-) of 0.14 and 0.21, respectively. Conclusion: This study revealed that SWE is useful in predicting malignancy. With the optimal cutoff values of E-mean and E-ratio at 90.35 kPa and 5.89, the sensitivity was nearly 90 % with E-mean and slightly over 80 % with E-ratio, respectively. These findings could be used in conjunction with conventional US.

20.
Carbohydr Polym ; 340: 122234, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-38858015

RESUMEN

Porous starch materials are promising in several applications as renewable natural biomaterials. This study reports an approach combining methacrylation of starch and chemical crosslinked cryogelation to fabricate highly elastic macroporous starch (ST-MA) cryogels with impressed water/oil absorption capacity and wet thermal stability among starch based porous materials. Five different types of starch, including pea, normal corn, high amylose corn, tapioca, and waxy maize starch with different amylose content, have been studied. The methacrylation degree is not related with amylose content. All cryogels exhibited excellent compressive elasticity enduring 90 % deformation without failure and good robustness in cyclic tests. The ST-MA cryogels from pea starch exhibited the highest Young's modulus and compressive strength among five types of starch. These covalent cryogels exhibit high wet-thermal stability and enzymatic hydrolysis stability, while still are biodegradable. The dry ST-MA sponges (2 wt%) showed outstanding liquid absorption capacity, absorbing ~40 folds (g/g) of water or ~ 36 folds (g/g) of oil respectively. All types of starch have similar liquid absorption performance. This study provides a universal approach to fabricate highly elastic covalent starch macroporous materials with impressed liquid absorption capacity and outstanding stability, especially wet-thermal stability, and may expand their applications.

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