Rapid Volume Changes Research Articles

Mechano-osmotic signals control chromatin state and fate transitions in pluripotent stem cells.

Acquisition of specific cell shapes and morphologies is a central component of cell fate transitions. Although signaling circuits and gene regulatory networks that regulate pluripotent stem cell differentiation have been intensely studied, how these networks are integrated in space and time with morphological transitions and mechanical deformations to control state transitions remains a fundamental open question. Here, we focus on two distinct models of pluripotency, primed pluripotent stem cells and pre-implantation inner cell mass cells of human embryos to discover that cell fate transitions associate with rapid changes in nuclear shape and volume which collectively alter the nuclear mechanophenotype. Mechanistic studies in human induced pluripotent stem cells further reveal that these phenotypical changes and the associated active fluctuations of the nuclear envelope arise from growth factor signaling-controlled changes in chromatin mechanics and cytoskeletal confinement. These collective mechano-osmotic changes trigger global transcriptional repression and a condensation-prone environment that primes chromatin for a cell fate transition by attenuating repression of differentiation genes. However, while this mechano-osmotic chromatin priming has the potential to accelerate fate transitions and differentiation, sustained biochemical signals are required for robust induction of specific lineages. Our findings uncover a critical mechanochemical feedback mechanism that integrates nuclear mechanics, shape and volume with biochemical signaling and chromatin state to control cell fate transition dynamics.

RELATIONSHIP BETWEEN ELECTROCARDIOGRAPHY AND ELECTROLYTES BEFORE AND AFTER DIALYSIS IN HEMODIALYSIS PATIENTS

Background: Cardiovascular events are the most important cause of mortality in hemodialysis patients. Rapid volume changes and electrolyte shifts during dialysis lead to arrhythmias. Objective: We aimed to determine whether there is a relationship between electrocardiographic (ECG) wave and interval changes and electrolyte levels before and after hemodialysis in dialysis patients. Materials and Method: A total of 112 patients undergoing hemodialysis three times a week for four hours for more than six months were included in the study. Before and after hemodialysis, 12-lead ECG, weight, arterial blood pressure, hemogram, biochemistry, and demographic data were recorded. Waves and intervals were calculated from the 12-lead ECG taken before and immediately after dialysis, and the relationship with serum electrolyte levels was evaluated. P

Numerical simulation for pressure fluctuations caused by the growth of a single boiling bubble

The pressure fluctuations caused by the rapid volume changes during the initial growth stage for a single bubble are crucial excitations of boiling induced vibration. Therefore, it is necessary to accurately model the dynamic behavior of bubbles during this stage to obtain reasonable excitation forces, which can be used to estimate the vibration response of structures. The present study develops a dynamics model, which is verified and validated to be applicable to the growth of spherical bubbles in infinite superheated liquid and hemispherical bubbles growing on a vertical heated surface. The effects of mass transfer are considered for the vapor-liquid interface motion, and the temperature variations at the liquid side are determined by the finite difference method. The numerical data match well with the theoretical and experimental results, and the characteristics of the excitation forces caused by a single boiling bubble are obtained and analyzed. In addition, the influences of superheat, accommodation coefficient for phase change, and the temperature gradient at the liquid side on excitation forces caused by bubble growth are studied. The results show that the temperature distributions near the heated surface strongly affect the frequency domain characteristics of the excitation forces.

Synergistic Tailoring of Electronic and Thermal Transports in Thermoelectric Se-Free n-Type (Bi,Sb)2Te3.

Se-free n-type (Bi,Sb)2Te3 thermoelectric materials, outperforming traditional n-type Bi2(Te,Se)3, emerge as a compelling candidate for practical applications of recovering low-grade waste heat. A 100% improvement in the maximum ZT of n-type Bi1.7Sb0.3Te3 is demonstrated by using melt-spinning and excess Te-assisted transient liquid phase sintering (LPS). Te-rich sintering promotes the formation of intrinsic defects (TeBi), elevating the carrier concentration and enhancing the electrical conductivity. Melt-spinning with excess Te fine-tunes the electronic band, resulting in a high power-factor of 0.35 × 10-3 W·m-1 K-2 at 300 K. Rapid volume change during sintering induces the formation of dislocation networks, significantly suppressing the lattice thermal conductivity (0.4 W·m-1 K-1). The developed n-type legs achieve a high maximum ZT of 1.0 at 450 K resulting in a 70% improvement in the output power of the thermoelectric device (7.7 W at a temperature difference of 250 K). This work highlights the synergy between melt-spinning and transient LPS, advancing the tailored control of both electronic and thermal properties in thermoelectric technology.

Membraneless and membrane-bound organelles in an anhydrobiotic cell line are protected from desiccation-induced damage.

Anhydrobiotic species can survive virtually complete water loss by entering a reversible ametabolic glassy state that may persist for years in ambient conditions. The Pv11 cell line was derived from the egg mass of the anhydrobiotic midge, Polypedilum vanderplanki, and is currently the only available anhydrobiotic cell line. Our results demonstrate that the necessary preconditioning for Pv11 cells to enter anhydrobiosis causes autophagy and reduces mitochondrial respiration by over 70%. We speculate that reorganizing cellular bioenergetics to create and conserve energy stores may be valuable to successfully recover after rehydration. Furthermore, mitochondria in preconditioned cells lose their membrane potential during desiccation but rapidly restore it within 30min upon rehydration, demonstrating that the inner mitochondrial membrane integrity is well-preserved. Strikingly, the nucleolus remains visible immediately upon rehydration in preconditioned cells while absent in control cells. In contrast, a preconditioning-induced membraneless organelle reformed after rehydration, demonstrating that membraneless organelles in Pv11 cells can be either stabilized or recovered. Staining the endoplasmic reticulum and the Golgi apparatus revealed that these organelles fragment during preconditioning. We hypothesize that this process reduces sheering stress caused by rapid changes in cellular volume during desiccation and rehydration. Additionally, preconditioning was found to cause the filamentous-actin (F-actin) network to disassemble significantly and reduce the fusion of adjacent plasma membranes. This study offers several exciting avenues for future studies in the animal model and Pv11 cell line that will further our understanding of anhydrobiosis and may lead to advancements in storing sensitive biologics at ambient temperatures for months or years.

Prolonged Labor and Adverse Cardiac Outcomes in Pregnant Patients With Congenital Heart Disease

(Am J Obstet Gynecol. 2023;228(6):728.e1–728.e8) Congenital heart disease (CHD) is one of the most common types of birth defects and affects 8 to 9 per 1000 births. Many patients who have it are diagnosed in infancy, but some are not diagnosed until later in life. The number of patients with CHD who reach childbearing years has increased substantially. Pregnancy can pose difficult challenges, especially in labor and delivery. The physiologic changes that occur during delivery, including increased cardiac demand, rapid changes in intravascular volume, and blood loss, result in significant risk for patients with CHD. The European Registry of Pregnancy and Cardiac disease and the Cardiac Disease in Pregnancy 2 studies have demonstrated that the immediate postpartum period is the highest risk time for heart failure.

Exploring facial overfilled syndrome from the perspective of anatomy and the mismatched delivery of fillers.

Facial fillers and injectables have transformed the landscape of cosmetic procedures, offering rejuvenation possibilities. However, the emergence of "Facial Overfilled Syndrome (FOS)" presents a concerning trend attributed to excessive filler use and suboptimal injection techniques. Understanding the interplay between facial aging and augmentation techniques is crucial in addressing and preventing FOS. Facial overfilled syndrome is characterized by the excessive use of fillers, resulting in a distorted and heavy appearance. It manifests in various forms, including 'flowerhorn' foreheads, 'sunset' eyes, 'chipmunk' cheeks, 'witch' chins, and 'pillow' faces. The syndrome arises from attempts to combat anatomical aging with dramatic filler treatments, causing rapid volume changes and skin tightening. Skeletal structures and soft tissue distribution across different ethnicities play a significant role in FOS development. Understanding the aging process across facial tissues is essential, as fillers cannot entirely reverse aging manifestations. Tailored assessment and treatment plans should precede filler injections, involving muscle assessment, observation of facial movements during injection, and ultrasound imaging of fat layers. Attention should be given to filler pressure and migration risks, particularly in areas with elevated pressure. Additionally, alternative approaches like energy-based devices and polymer reinforcement of facial ligaments should be considered to minimize filler use. Ethnic variations in facial anatomy require careful consideration to avoid overcorrection. FOS predominantly affects individuals of East Asian descent due to specific facial characteristics. Prevention strategies involve minimizing filler use, addressing underlying bone changes, and considering ethnic and gender differences in facial anatomy. Recent MRI and ultrasound studies challenge the notion of filler breakdown, emphasizing the importance of filler selection and injection techniques. Education, individualized treatments, and a holistic understanding of facial anatomy are key to preventing and managing FOS and ensuring natural and harmonious facial aesthetics.

Abstract 18676: Aneurysmectomy or No Aneurysmectomy - An Unknown Heart Failure Terrain

Case Report: A 40-year male with a history of traumatic inferoapical ventricular septal rupture after a motor vehicle accident status post patch repair and left ventricular thrombus on Rivaroxaban presented to the ED with hemoptysis. The patient on arrival was hemodynamically stable. CTA revealed a new 6.9 cm left ventricular pseudoaneurysm and an echocardiogram revealed an EF of 30% with a pseudoaneurysm involving the entire distal septum, lateral wall, and apex and a ventricular septal rupture into the intraventricular septum. Cardiac MRI revealed a pseudoaneurysm from the inferoseptal wall measuring 9.6 x 6.9 x 10.0 cm and a stroke volume of 123 mL. A right heart catheterization revealed no evidence of left-to-right shunting. Given heart failure with reduced ejection fraction in the setting of a pseudoaneurysm and the complexity of aneurysm repair, advanced heart failure and cardiothoracic surgery teams were consulted for conventional surgical and transplant evaluation. Due to social barriers, the patient was declined from transplant and ultimately proceeded with patch repair. Intraoperative echocardiography revealed a post-operative EF of 25%. Discussion: This case highlights the need for further data on pseudoaneurysms that are confounded with concurrent heart failure. For this patient, the concerns were for adequate stroke volume given the extent of the pseudoaneurysm and whether improvement in systolic function could be seen with repair or result in further decline. It was postulated that surgical repair would raise his effective stroke volume, and thus improve cardiac function. Postoperative EF changes could have been further explained by myocardial stunning during anesthesia or rapid changes in end-diastolic volume with aneurysmectomy altering Frank-Starling hemodynamics. With isolated case report data, further aneurysmectomy outcome characterization is thus imperative to guide advanced heart failure treatment and improve patient mortality.

Sb/C composite embedded in SiOC buffer matrix via dispersion property control for novel anode material in sodium-ion batteries

Due to vast sodium reserves, sodium-ion batteries (SIBs) are more cost-efficient to produce than lithium-ion batteries. Therefore, they are actively researched as next-generation energy storage materials. Antimony is a promising anode material for SIB owing to its high theoretical capacity (660 mA h g−1) and an appropriate sodiation voltage. However, due to the rapid volume change during sodium intercalation and deintercalation, cycling stability is poor, presenting a significant obstacle to the practical application of SIBs. Alleviating the Sb volume expansion throughout the charging and discharging processes is the key to the practical implementation of Sb-based anodes. Herein, Sb/C–SiOC composites are prepared using the hydrogen bonding-based adsorption properties of metal-organic frameworks (MOFs). The final product, the Sb/C–SiOC composites, exhibited significantly improved cycle performance, such as maintaining the initial capacity after 200 cycles by the SiOC matrix acting as a conductive buffer. Additionally, the presence of MOF-derived mesoporous carbon and SiOC contributed to the improved rate performance. The hydrogen bond-based adsorption properties of the MOFs used in this study can be effectively applied to uniformly introduce a matrix or coating layer that relieves the volume expansion of high-capacity composite anodes, making it an effective strategy for developing alloy-based energy storage materials.

SurfFlow: A Flow-Based Approach for Rapid and Accurate Cortical Surface Reconstruction from Infant Brain MRI.

The infant brain undergoes rapid changes in volume, shape, and structural organization during the first postnatal year. Accurate cortical surface reconstruction (CSR) is essential for understanding rapid changes in cortical morphometry during early brain development. However, existing CSR methods, designed for adult brain MRI, fall short in reconstructing cortical surfaces from infant MRI, owing to the poor tissue contrasts, partial volume effects, and rapid changes in cortical folding patterns. Here, we introduce an infant-centric CSR method in light of these challenges. Our method, SurfFlow, utilizes three seamlessly connected deformation blocks to sequentially deform an initial template mesh to target cortical surfaces. Remarkably, our method can rapidly reconstruct a high-resolution cortical surface mesh with 360k vertices in approximately one second. Performance evaluation based on an MRI dataset of infants 0 to 12 months of age indicates that SurfFlow significantly reduces geometric errors and substantially improves mesh regularity compared with state-of-the-art deep learning approaches.

Recent advances of structural/interfacial engineering for Na metal anode protection in liquid/solid-state electrolytes.

Na metal anode is one of most promising anode materials for next-generation secondary batteries. However, the practical application of Na anode is limited by dendritic growth, rapid volume change, and serious interface problems in the process of Na electroplating/stripping, resulting in low coulombic efficiency, short life, and safety issues of sodium metal batteries (SMBs). Herein, the cyclic instability mechanisms of the Na anode and the corresponding advanced protection strategies including in situ solid-electrolyte-interphase (SEI), artificial SEI, and three-dimensional conductive frame, are systematically reviewed. Notably, this review summarizes the latest research progress on interface modification and electrode modification of all-solid-state SMBs. Finally, the outlooks of anode interphase in SMBs are summarized and prospected, providing a promising way for high-energy and safe SMBs.

The Hippo pathway drives the cellular response to hydrostatic pressure

Cells need to rapidly and precisely react to multiple mechanical and chemical stimuli in order to ensure precise context‐dependent responses. This requires dynamic cellular signalling events that ensure homeostasis and plasticity when needed. A less well‐understood process is cellular response to elevated interstitial fluid pressure, where the cell senses and responds to changes in extracellular hydrostatic pressure. Here, using quantitative label‐free digital holographic imaging, combined with genome editing, biochemical assays and confocal imaging, we analyse the temporal cellular response to hydrostatic pressure. Upon elevated cyclic hydrostatic pressure, the cell responds by rapid, dramatic and reversible changes in cellular volume. We show that YAP and TAZ, the co‐transcriptional regulators of the Hippo signalling pathway, control cell volume and that cells without YAP and TAZ have lower plasma membrane tension. We present direct evidence that YAP/TAZ drive the cellular response to hydrostatic pressure, a process that is at least partly mediated via clathrin‐dependent endocytosis. Additionally, upon elevated oscillating hydrostatic pressure, YAP/TAZ are activated and induce TEAD‐mediated transcription and expression of cellular components involved in dynamic regulation of cell volume and extracellular matrix. This cellular response confers a feedback loop that allows the cell to robustly respond to changes in interstitial fluid pressure.

Physical properties of the cytoplasm modulate the rates of microtubule polymerization and depolymerization.

The cytoplasm is a crowded, visco-elastic environment whose physical properties change according to physiological or developmental states. How the physical properties of the cytoplasm impact cellular functions invivo remains poorly understood. Here, we probe the effects of cytoplasmic concentration on microtubules by applying osmotic shifts to fission yeast, moss, and mammalian cells. We show that the rates of both microtubule polymerization and depolymerization scale linearly and inversely with cytoplasmic concentration; an increase in cytoplasmic concentration decreases the rates of microtubule polymerization and depolymerization proportionally, whereas a decrease in cytoplasmic concentration leads to the opposite. Numerous lines of evidence indicate that these effects are due to changes in cytoplasmic viscosity rather than cellular stress responses or macromolecular crowding per se. We reconstituted these effects on microtubules invitro by tuning viscosity. Our findings indicate that, even in normal conditions, the viscosity of the cytoplasm modulates the reactions that underlie microtubule dynamic behaviors.

A Repurposed Drug Screen for Compounds Regulating Aquaporin 5 Stability in Lung Epithelial Cells.

Aquaporin 5 (AQP5) is expressed in several cell types in the lung and regulates water transport, which contributes to barrier function during injury and the composition of glandular secretions. Reduced AQP5 expression is associated with barrier dysfunction during acute lung injury, and strategies to enhance its expression are associated with favorable phenotypes. Thus, pharmacologically enhancing AQP5 expression could be beneficial. Here, we optimized a high-throughput assay designed to detect AQP5 abundance using a cell line stably expressing bioluminescent-tagged AQP5. We then screened a library of 1153 compounds composed of FDA-approved drugs for their effects on AQP5 abundance. We show compounds Niclosamide, Panobinostat, and Candesartan Celexitil increased AQP5 abundance, and show that Niclosamide has favorable cellular toxicity profiles. We determine that AQP5 levels are regulated in part by ubiquitination and proteasomal degradation in lung epithelial cells, and mechanistically Niclosamide increases AQP5 levels by reducing AQP5 ubiquitination and proteasomal degradation. Functionally, Niclosamide stabilized AQP5 levels in response to hypotonic stress, a stimulus known to reduce AQP5 levels. In complementary assays, Niclosamide increased endogenous AQP5 in both A549 cells and in primary, polarized human bronchial epithelial cells compared to control-treated cells. Further, we measured rapid cell volume changes in A549 cells in response to osmotic stress, an effect controlled by aquaporin channels. Niclosamide-treated A549 cell volume changes occurred more rapidly compared to control-treated cells, suggesting that increased Niclosamide-mediated increases in AQP5 expression affects functional water transport. Taken together, we describe a strategy to identify repurposed compounds for their effect on AQP5 protein abundance. We validated the effects of Niclosamide on endogenous AQP5 levels and in regulating cell-volume changes in response to tonicity changes. Our findings highlight a unique approach to screen for drug effects on protein abundance, and our workflow can be applied broadly to study compound effects on protein abundance in lung epithelial cells.

Disassembly and Mislocalization of AQP4 in Incipient Scar Formation after Experimental Stroke.

There is an urgent need to better understand the mechanisms involved in scar formation in the brain. It is well known that astrocytes are critically engaged in this process. Here, we analyze incipient scar formation one week after a discrete ischemic insult to the cerebral cortex. We show that the infarct border zone is characterized by pronounced changes in the organization and subcellular localization of the major astrocytic protein AQP4. Specifically, there is a loss of AQP4 from astrocytic endfoot membranes that anchor astrocytes to pericapillary basal laminae and a disassembly of the supramolecular AQP4 complexes that normally abound in these membranes. This disassembly may be mechanistically coupled to a downregulation of the newly discovered AQP4 isoform AQP4ex. AQP4 has adhesive properties and is assumed to facilitate astrocyte mobility by permitting rapid volume changes at the leading edges of migrating astrocytes. Thus, the present findings provide new insight in the molecular basis of incipient scar formation.

A century of exercise physiology: key concepts in muscle cell volume regulation

Skeletal muscle cells can both gain and lose volume during periods of exercise and rest. Muscle cells do not behave as perfect osmometers because the cell volume changes are less than predicted from the change in extracellular osmolality. Therefore, there are mechanisms involved in regulating cell volume, and they are different for regulatory volume decreases and regulatory volume increases. Also, after an initial rapid change in cell volume, there is a gradual and partial recovery of cell volume that is effected by ion and water transport mechanisms. The mechanisms have been studied in non-contracting muscle cells, but remain to be fully elucidated in contracting muscle. Changes in muscle cell volume are known to affect the strength of contractile activity as well as anabolic/catabolic signaling, perhaps indicating that cell volume should be a regulated variable in skeletal muscle cells. Muscles contracting at moderate to high intensity gain intracellular volume because of increased intracellular osmolality. Concurrent increases in interstitial (extracellular) muscle volume occur from an increase in osmotically active molecules and increased vascular filtration pressure. At the same time, non-contracting muscles lose cell volume because of increased extracellular (blood) osmolality. This review provides the physiological foundations and highlights key concepts that underpin our current understanding of volume regulatory processes in skeletal muscle, beginning with consideration of osmosis more than 200years ago and continuing through to the process of regulatory volume decrease and regulatory volume increase.

DATA SOURCES IN BUSINESS ENVIRONMENT ANALYTICS AND THEIR TRANSFORMATION IN THE DIGITAL ECONOMY

Abstract. The massive data growth, the variety of its sources and analysis tools necessitates review and critical analysis of data types to analyze business environments and make decisions. These tasks are relevant for public authorities regulating the economy, groups engaged in business consulting, and analytical centers specializing in strategic analysis, economic security, and market and competitor studies. The article aims to summarize and systematize modern types and sources of data in the study of the business environment in Ukraine, as well as their formats in the context of transformation into analysis platforms and insights for organizational decision-making. The study used a systemic-structural approach, as well as general scientific research methods – analysis, synthesis, and comparison. The authors propose a classification of data types, systematize their sources and format, and summarize data and analytics platforms that can be used to analyse and regulate the business environment in Ukraine. The authors conclude that modern business environment analytics are characterized by rapid changes in volume and sources of data, as well as analytical tools. Indicators of such changes are 1) an increase in open data, primarily due to availability of public information in the Open Data format 2) diversification of data formats, allowing further processing and analysis, in particular Data Mining, and 3) the growth of opportunities for business entities to independently make analytics based on public registers and other sources of open data. Accurate definition and use of various types of data, taking into account their sources, access modes and formats, is a key determinant of the quality of economic analytics in the process of decision-making, including in the field of government regulation of the economy. Keywords: business environment, open data, information, data and analysis platform, statistical information.

Application of exfoliated graphene as conductive additive for lithium-ion secondary batteries

We established that the application of exfoliated graphene as the conductive additive in the anode active material of the secondary battery was effective in improving the charge/discharge cycle characteristics compared to commonly used carbon materials, such as Ketjenblack and graphite. Exfoliated synthetic graphene produced using a biaxial independently controlled three-dimensional rotary ball mill has a unique shape. In order to uniformly disperse it in the electrode, while maintaining a flake shape thinner than graphene, we develop a dispersion technology using a wet process that utilizes a homogenizer and jet mill. Although the resistance component of the electrode synthesized by mixing exfoliated graphene with powdered silicon is greater than those of the other carbon materials, it is considered advantageous as a conductive additive because it ensures physical contact with the active material, even when the anode matrix disintegrates due to the rapid volume changes in silicon by repeated charge/discharge.

Controlled drug release of levofloxacin from poly (acrylamide) hydrogel

Hydrogels are 3D polymer networks capable to absorb and release water or biological fluids. They are stimuli-responsive materials, which can show rapid volume changes with response to small changes in environmental parameters such as ionic strength, pH, and temperature. In this work, we performed a synthesis of Poly(acrylamide) hydrogel and tested for controlled release of levofloxacin hemihydrate as a model drug. We used sodium metabisulfite and potassium persulphate as free radical initiators to prepare hydrogel with methylenebisacrylamide as a crosslinker. Characterization of hydrogel was performed by TGA, SEM, and FT-IR. Swelling study and drug release were performed at pH 1.2 and 7.4 solutions, identical to the gastrointestinal fluid at 37°C (human body temperature) to examine possible site-specific drug delivery. UV-Visible spectrophotometer was used to measure the concentration of drug release. Results exhibited the pH and temperature-dependent drug release. The amount of drug release was found to be 17% and 99% in acidic and alkaline pH of 1.2 and 7.4, respectively, after 6 hours.

Methodology: Non-face-to-face teaching for formative art courses of the design majors

On this study, engineering properties of SGR method and SMI method, which are typical sodium silicate methods, were compared through the laboratory test and durability, strength, waterproof characteristic and environmental effects were compared and analyzed with period and condition of curing on each case. As a result of durability test, volume change of SGR is approximately 23-times greater than SMI and the effects on environment are appeared safe on all method. In case of waterproof characteristic test, permeability coefficient is decreased about 24% on SMI, whereas on SGR permeability coefficient is showed to increase because rapid volume change make wider void. Strength characteristics of SMI are appeared higher about 11-times in case of homogel and 3.9-times in case of sandgel than SGR. Which is because volume change of SMI, caused by leaching, is smaller than SGR.