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Nature Cell Biology Sep 2023The nuclear envelope (NE) is a spherical double membrane with elastic properties. How NE shape and elasticity are regulated by lipid chemistry is unknown. Here we...
The nuclear envelope (NE) is a spherical double membrane with elastic properties. How NE shape and elasticity are regulated by lipid chemistry is unknown. Here we discover lipid acyl chain unsaturation as essential for NE and nuclear pore complex (NPC) architecture and function. Increased lipid saturation rigidifies the NE and the endoplasmic reticulum into planar, polygonal membranes, which are fracture prone. These membranes exhibit a micron-scale segregation of lipids into ordered and disordered phases, excluding NPCs from the ordered phase. Balanced lipid saturation is required for NPC integrity, pore membrane curvature and nucleocytoplasmic transport. Oxygen deprivation amplifies the impact of saturated lipids, causing NE rigidification and rupture. Conversely, lipid droplets buffer saturated lipids to preserve NE architecture. Our study uncovers a fundamental link between lipid acyl chain structure and the integrity of the cell nucleus with implications for nuclear membrane malfunction in ischaemic tissues.
Topics: Nuclear Envelope; Nuclear Pore; Cell Nucleus; Elasticity; Lipids
PubMed: 37591950
DOI: 10.1038/s41556-023-01207-8 -
Plastic and Reconstructive Surgery Apr 2019Injectable hyaluronic acid fillers are routinely used for correction of soft-tissue volume loss and facial rejuvenation. Product differentiation has primarily been based...
BACKGROUND
Injectable hyaluronic acid fillers are routinely used for correction of soft-tissue volume loss and facial rejuvenation. Product differentiation has primarily been based on the rheologic parameter known as elastic modulus (G'), although other physicochemical properties are being explored to characterize potential product performance. As clinical data regarding product performance are lacking, the practical experience of injectors provides a valuable bridge in the knowledge gap between product rheologic data and product use.
METHODS
Rheologic and physicochemical measurements (swelling factor and cohesion) were collected for 18 products. To observe the impact of G' and hyaluronic acid concentration on swelling factor and cohesion, proportional relationships were evaluated. Contributing authors were queried regarding their G'-based selection of products when considering skin quality, degree of correction, injection depth, and anatomical location.
RESULTS
Relationships were observable between G' and swelling factor and G' and cohesion only when limited to products manufactured by the same crosslinking technology and the same concentration. No relationship between isolated hyaluronic acid concentration and swelling factor or cohesion was apparent. Although rheological parameters and the assumptions of ex vivo data translating to in vivo performance are oftentimes not completely aligned, in the clinical experience of the authors, in general, higher G' products are better suited for thicker skin and deeper injection planes, whereas lower G' products are better for more superficial planes, although exceptions to these trends are also made based on technical experience.
CONCLUSIONS
While rheologic and physicochemical characteristics can vary widely between products and the methods and measurements of these parameters are often difficult to correlate, G' represents a useful and consistent parameter for product differentiation. Understanding how to select products based on G' is valuable knowledge for customizing injection plans and contributes to an optimal aesthetic outcome.
Topics: Dermal Fillers; Elasticity; Face; Gels; Humans; Hyaluronic Acid; Injections; Rheology
PubMed: 30921116
DOI: 10.1097/PRS.0000000000005429 -
Advanced Science (Weinheim,... Dec 2022Wearables and bioelectronics rely on breathable interface devices with bioaffinity, biocompatibility, and smart functionality for interactions between beings and things... (Review)
Review
Wearables and bioelectronics rely on breathable interface devices with bioaffinity, biocompatibility, and smart functionality for interactions between beings and things and the surrounding environment. Elastic fibers/fabrics with mechanical adaptivity to various deformations and complex substrates, are promising to act as fillers, carriers, substrates, dressings, and scaffolds in the construction of biointerfaces for the human body, skins, organs, and plants, realizing functions such as energy exchange, sensing, perception, augmented virtuality, health monitoring, disease diagnosis, and intervention therapy. This review summarizes and highlights the latest breakthroughs of elastic fibers/fabrics for wearables and bioelectronics, aiming to offer insights into elasticity mechanisms, production methods, and electrical components integration strategies with fibers/fabrics, presenting a profile of elastic fibers/fabrics for energy management, sensors, e-skins, thermal management, personal protection, wound healing, biosensing, and drug delivery. The trans-disciplinary application of elastic fibers/fabrics from wearables to biomedicine provides important inspiration for technology transplantation and function integration to adapt different application systems. As a discussion platform, here the main challenges and possible solutions in the field are proposed, hopefully can provide guidance for promoting the development of elastic e-textiles in consideration of the trade-off between mechanical/electrical performance, industrial-scale production, diverse environmental adaptivity, and multiscenario on-spot applications.
Topics: Humans; Elastic Tissue; Textiles; Wound Healing; Elasticity; Wearable Electronic Devices
PubMed: 36253094
DOI: 10.1002/advs.202203808 -
Nature Materials Aug 2022Elastic properties of classical bulk materials can hardly be changed or adjusted in operando, while such tunable elasticity is highly desired for robots and smart...
Elastic properties of classical bulk materials can hardly be changed or adjusted in operando, while such tunable elasticity is highly desired for robots and smart machinery. Although possible in reconfigurable metamaterials, continuous tunability in existing designs is plagued by issues such as structural instability, weak robustness, plastic failure and slow response. Here we report a metamaterial design paradigm using gears with encoded stiffness gradients as the constituent elements and organizing gear clusters for versatile functionalities. The design enables continuously tunable elastic properties while preserving stability and robust manoeuvrability, even under a heavy load. Such gear-based metamaterials enable excellent properties such as continuous modulation of Young's modulus by two orders of magnitude, shape morphing between ultrasoft and solid states, and fast response. This allows for metamaterial customization and brings fully programmable materials and adaptive robots within reach.
Topics: Elastic Modulus; Elasticity
PubMed: 35681063
DOI: 10.1038/s41563-022-01269-3 -
Annual Review of Biophysics May 2022Cellular membranes self-assemble from and interact with various molecular species. Each molecule locally shapes the lipid bilayer, the soft elastic core of cellular... (Review)
Review
Cellular membranes self-assemble from and interact with various molecular species. Each molecule locally shapes the lipid bilayer, the soft elastic core of cellular membranes. The dynamic architecture of intracellular membrane systems is based on elastic transformations and lateral redistribution of these elementary shapes, driven by chemical and curvature stress gradients. The minimization of the total elastic stress by such redistribution composes the most basic, primordial mechanism of membrane curvature-composition coupling (CCC). Although CCC is generally considered in the context of dynamic compositional heterogeneity of cellular membrane systems, in this article we discuss a broader involvement of CCC in controlling membrane deformations. We focus specifically on the mesoscale membrane transformations in open, reservoir-governed systems, such as membrane budding, tubulation, and the emergence of highly curved sites of membrane fusion and fission. We reveal that the reshuffling of molecular shapes constitutes an independent deformation mode with complex rheological properties.This mode controls effective elasticity of local deformations as well as stationary elastic stress, thus emerging as a major regulator of intracellular membrane remodeling.
Topics: Cell Membrane; Elasticity; Lipid Bilayers; Membrane Fusion
PubMed: 35239417
DOI: 10.1146/annurev-biophys-011422-100054 -
Current Opinion in Ophthalmology Jul 2018Assessment of corneal biomechanics has been an unmet clinical need in ophthalmology for many years. Many researchers and clinicians have identified corneal biomechanics... (Review)
Review
PURPOSE OF REVIEW
Assessment of corneal biomechanics has been an unmet clinical need in ophthalmology for many years. Many researchers and clinicians have identified corneal biomechanics as source of variability in refractive procedures and one of the main factors in keratoconus. However, it has been difficult to accurately characterize corneal biomechanics in patients. The recent development of Brillouin light scattering microscopy heightens the promise of bringing biomechanics into the clinic. The aim of this review is to overview the progress and discuss prospective applications of this new technology.
RECENT FINDINGS
Brillouin microscopy uses a low-power near-infrared laser beam to determine longitudinal modulus or mechanical compressibility of tissue by analyzing the return signal spectrum. Human clinical studies have demonstrated significant difference in the elastic properties of normal corneas versus corneas diagnosed with mild and severe keratoconus. Clinical data have also shown biomechanical changes after corneal cross-linking treatment of keratoconus patients. Brillouin measurements of the crystalline lens and sclera have also been demonstrated.
SUMMARY
Brillouin microscopy is a promising technology under commercial development at present. The technique enables physicians to characterize the biomechanical properties of ocular tissues.
Topics: Biomechanical Phenomena; Cornea; Elasticity; Humans; Keratoconus; Microscopy
PubMed: 29771749
DOI: 10.1097/ICU.0000000000000489 -
BMC Public Health Jul 2022The sale of aerated or sugar-sweetened beverages (ASBs) has been consistently growing in India which has also experienced a major increase in non-communicable diseases....
BACKGROUND
The sale of aerated or sugar-sweetened beverages (ASBs) has been consistently growing in India which has also experienced a major increase in non-communicable diseases. This study estimates the price elasticities of ASBs by different household-income groups in India and examine the trends in their affordability.
METHODS
The price elasticity for ASBs were estimated using a nationally representative household sample survey on consumption of ASBs in India and with Deaton's method which is robust to self-reported household expenditure surveys. Trends in affordability of ASBs were estimated using relative income price (RIP) which measured the proportion of per capita gross domestic product (GDP) required to purchase 100 L of ASBs in a given year. The elasticity parameters were used to estimate the incremental tax needed for a 10% reduction in ASB consumption.
RESULTS
The own-price elasticity of ASBs is - 0.94 in the overall sample and varied between - 1.04 to - 0.83 from low- to high-income households. There has been an annual average decline of about 6.8% in RIP of ASBs or an increase in their affordability over the last 13 years. Increasing the compensation cess on ASBs under the current Goods and Services Tax (GST) to 29%, will have the effect of decreasing ASB consumption by 10% and increasing the tax revenue by about 27%.
CONCLUSION
The taxation policy on ASBs in India has largely been ineffective at increasing the real retail prices of ASBs as a result of which ASB consumption grew. ASBs should be classified along with other unhealthy products like tobacco and alcohol as demerit products for the purpose of taxation and their taxes should be regularly increased sufficiently enough to compensates for both general price inflation and income growth so as to decreases their affordability.
Topics: Beverages; Commerce; Costs and Cost Analysis; Elasticity; Humans; Sugar-Sweetened Beverages; Taxes
PubMed: 35842635
DOI: 10.1186/s12889-022-13736-2 -
Journal of Medical Ultrasonics (2001) Oct 2021It has been recognized that tissue stiffness provides useful diagnostic information, as with palpation as a screening for diseases such as cancer. In recent years, shear... (Review)
Review
It has been recognized that tissue stiffness provides useful diagnostic information, as with palpation as a screening for diseases such as cancer. In recent years, shear wave elastography (SWE), a technique for evaluating and imaging tissue elasticity quantitatively and objectively in diagnostic imaging, has been put into practical use, and the amount of clinical knowledge about SWE has increased. In addition, some guidelines and review papers regarding technology and clinical applications have been published, and the status as a diagnostic technology is in the process of being established. However, there are still unclear points about the interpretation of shear wave speed (SWS) and converted elastic modulus in SWE. To clarify these, it is important to investigate the factors that affect the SWS and elastic modulus. Therefore, physical and engineering factors that potentially affect the SWS and elastic modulus are discussed in this review paper, based on the principles of SWE and a literature review. The physical factors include the propagation properties of shear waves, mechanical properties (viscoelasticity, nonlinearity, and anisotropy), and size and shape of target tissues. The engineering factors include the region of interest depth and signal processing. The aim of this review paper is not to provide an answer to the interpretation of SWS. It is to provide information for readers to formulate and verify the hypothesis for the interpretation. Therefore, methods to verify the hypothesis for the interpretation are also reviewed. Finally, studies on the safety of SWE are discussed.
Topics: Elastic Modulus; Elasticity Imaging Techniques; Humans
PubMed: 34453649
DOI: 10.1007/s10396-021-01127-w -
BMJ Open Jul 2022This study assessed the extent to which the elasticity of cigarette and waterpipe tobacco products differs between men and women. We also explored the levels of...
OBJECTIVES
This study assessed the extent to which the elasticity of cigarette and waterpipe tobacco products differs between men and women. We also explored the levels of substitution and complementarity in tobacco products among men and women.
SETTING
The study examines tobacco elasticities in three Arab countries: Lebanon, Jordan and the West Bank of Palestine.
PARTICIPANTS
We used data from nationally representative surveys of adults aged ≥18 years in Lebanon (n=1680), Jordan (n=1925) and Palestine (n=1679). The proportion of women was 50.0% of the sample in Lebanon and Palestine, and 44.6% in Jordan.
PRIMARY AND SECONDARY OUTCOME MEASURES
A zero-inflated Poisson regression model estimated own-price and cross-price elasticities for two variations of cigarettes and five variations of waterpipe tobacco products. Elasticities were measured based on eight scenarios of prices.
RESULTS
Demand for waterpipe tobacco products was elastic for both men and women. The cross-price elasticities in the three countries indicate the existence of substitution between cigarettes and waterpipe products and by different varieties within each of the two tobacco products. Gender differences varied across the three countries whereby higher cross-price elasticities were observed for women in Jordan and Palestine. For example, the price elasticity for discount waterpipe was -1.4 and -0.6 for women and men in Jordan, respectively.
CONCLUSIONS
Results on the elasticity of demand for tobacco products and the existence of substitution between tobacco products reveal the higher responsiveness of men and women to changes in tobacco prices. This should be taken into consideration in tobacco control strategies particularly when reducing tobacco consumption via taxation policies.
Topics: Adolescent; Adult; Arabs; Cigarette Smoking; Commerce; Elasticity; Female; Humans; Jordan; Lebanon; Male; Sex Factors; Taxes; Nicotiana; Tobacco Products; Water Pipe Smoking
PubMed: 35851023
DOI: 10.1136/bmjopen-2021-058495 -
IEEE Transactions on Ultrasonics,... Jun 2020Viscoelastic response (VisR) ultrasound characterizes the viscoelastic properties of tissue by fitting acoustic radiation force (ARF)-induced displacements in the region...
Viscoelastic response (VisR) ultrasound characterizes the viscoelastic properties of tissue by fitting acoustic radiation force (ARF)-induced displacements in the region of ARF excitation to a 1-D mass-spring-damper (MSD) model. Elasticity and viscosity are calculated separately but relative to the applied ARF amplitude. We refer to these parameters as "relative elasticity (RE)" and "relative viscosity (RV)." We herein test the hypothesis that RE and RV linearly correlate to true elasticity and viscosity in tissue. VisR imaging was simulated in 144 homogeneous viscoelastic materials with varying elasticities and viscosities. Derived RE linearly correlated with material elasticity and varied by an average of 2.52% when the material viscosity changed from 0.1 to 1.3 Pa · s. Derived RV linearly correlated with material viscosity but varied by an average of 102.5% when material elasticity changed from 3.33 to 20 kPa. The effect of elasticity on RV measurement was compensated using the slope of the linear relationship between RV and natural frequency ( ω ). After compensation, RV [Formula: see text] (elasticity compensated RV) linearly correlated with material viscosity and varied by less than 1.00% on average when the modeled shear elastic modulus changed from 3.3 to 20 kPa. In addition to elasticity compensation, variation in ARF amplitude over depth was compensated, yielding RE and [Formula: see text]. RE and [Formula: see text] successfully contrasted elastic and viscous inclusions, respectively, in three simulated phantoms. Experimentally, in the homogeneous oil-in-gelatin phantoms and excised livers, RE linearly correlated with shear wave dispersion ultrasound vibrometry (SDUV) derived shear elastic modulus, and [Formula: see text] linearly correlated with SDUV-derived shear viscosity. In excised livers containing viscoelastic oil-in-gelatin inclusions, the inclusions were successfully contrasted from the liver background by both RE and [Formula: see text]. These results suggest that RE and RV are relevant for qualitatively assessing the elastic and viscous properties of tissue.
Topics: Animals; Computer Simulation; Dogs; Elasticity; Elasticity Imaging Techniques; Image Processing, Computer-Assisted; Liver; Phantoms, Imaging; Viscosity
PubMed: 31899421
DOI: 10.1109/TUFFC.2019.2962789