Increase In Fiber Diameter Research Articles

Mechanical properties of steel fibre–UHPC interface: Experimental study and numerical simulation

The aim of this study was to investigate the interfacial mechanical attributes between steel fibre (SF) and an ultra-high-performance concrete (UHPC) matrix. Using both experimental testing and numerical simulation, a comprehensive analysis on the pull-out process of SF from the UHPC matrix was conducted. The effects of fibre embedment depth, fibre diameter and fibre embedment angle on the mechanical properties of the SF–UHPC interface were examined. In the fibre pull-out tests, the maximum pull-out force of the group of specimens with different embedment depths showed a trend of rapid rise and then slow development, and the pull-out work increased with an increase in embedment depth. The maximum pull-out force and pull-out work of the group with variable fibre diameters increased with an increase in fibre diameter. The maximum pull-out force and pull-out work of the group with different embedment angles increased first and then decreased with an increase in embedment angle. The maximum pull-out force was 72.5 N when the embedment angle was 45° and the maximum pull-out work was 214.4 N.mm when the embedment angle was 30°. The results of finite-element simulations were found to be in good agreement with the experimental results.

Transcriptome analysis identifies potential molecular mechanisms for growth of fast muscle in Chinese perch juvenile

Chinese perch (Siniperca chuatsi) is an important commercial fish species in China. Understanding the molecular mechanisms of growth and development of skeletal muscle is helpful for selection breeding and improving the growth rate of Chinese perch. We analyzed histological and transcriptomic differences in fast muscle of Chinese perch between 30 days post hatching (dph) and 60 dph using histological sections and high-throughput RNA-Seq. The results showed that the diameter of muscle fibers in 30 dph Chinese perch was mainly distributed in range of 30 − 40 μm, and that of 60 dph was primarily in the range of 40 − 50 μm. 34 differentially expressed genes (DEGs) were identified in the fast muscle of Chinese perch between 30 and 60 dph, of which 9 were up-regulated and 25 were down-regulated (60 dph vs 30 dph). The DEGs, including MYH4, ENO3, Bag3, krt13 and krt18, are associated with muscle cell differentiation and fusion in Chinese perch. The analysis of the protein–protein interaction network of DEGs revealed that FOS, junb and EGR1 may involve in the development of fast muscle. KEGG enrichment results showed that the up-regulated genes in the 60 dph were associated with several pathways related to metabolism and protein synthesis, such as glycosphingolipid biosynthesis and aminoacyl-tRNA biosynthesis. The results suggest that the development of fast muscle in Chinese perch from 30 to 60 dph is accompanied by an increase in muscle fiber diameter and changes in gene expression related to muscle cell differentiation and protein synthesis.Abbreviations: DEGs, differentially expressed genes; dph, days post hatching; FC, fold change; FDR, False Discovery Rate; GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; MyHCs, Myosin heavy chains; qRT-PCR, quantitative real-time PCR.

Comprehensive quantitative magnetic resonance imaging assessment of skeletal muscle pathophysiology in golden retriever muscular dystrophy: Insights from multicomponent water T2 and extracellular volume fraction.

Quantitative MRI and MRS have become important tools for the assessment and management of patients with neuromuscular disorders (NMDs). Despite significant progress, there is a need for new objective measures with improved specificity to the underlying pathophysiological alteration. This would enhance our ability to characterize disease evolution and improve therapeutic development. In this study, qMRI methods that are commonly used in clinical studies involving NMDs, like water T2 (T2H2O) and T1 and fat-fraction (FF) mapping, were employed to evaluate disease activity and progression in the skeletal muscle of golden retriever muscular dystrophy (GRMD) dogs. Additionally, extracellular volume (ECV) fraction and single-voxel bicomponent water T2 relaxometry were included as potential markers of specific histopathological changes within the tissue. Apart from FF, which was not significantly different between GRMD and control dogs and showed no trend with age, T2H2O, T1, ECV, and the relative fraction of the long-T2 component, A2, were significantly elevated in GRMD dogs across all age ranges. Moreover, longitudinal assessment starting at 2months of age revealed significant decreases in T2H2O, T1, ECV, A2, and the T2 of the shorter-T2 component, T21, in both control and GRMD dogs during their first year of life. Notably, insights from ECV and bicomponent water T2 indicate that (I) the elevated T2H2O and T1 values observed in dystrophic muscle are primarily driven by an expansion of the extracellular space, likely driven by the edematous component of inflammatory responses to tissue injury and (II) the significant decrease of T2H2O and T1 with age in control and GRMD dogs reflects primarily the progressive increase in fiber diameter and protein content during tissue development. Our study underscores the potential of multicomponent water T2 relaxometry and ECV to provide valuable insights into muscle pathology in NMDs.

Novel thermal-regulation and temperature-responsive controlled-release fibermats with porous sheath-core structures

Active regulation of the wound microenvironment as well as on-demand drug delivery have proven to be effective ways to accelerate wound healing, and the development of advanced textiles offers feasibility. A novel fibermat with thermal-regulation and temperature-responsive controlled-release properties was fabricated by using coaxial electrospinning, consisting of porous sheath-core polylactic acid (PLA)/ polyethylene glycol (PEG) fibers. The pore generation in the PLA shell of the PLA/PEG fiber was achieved through a phase separation method. The fiber diameter and pore size of the obtained fiber could be controlled by adjusting the flow rate of shell solution during electrospinning. Increasing the flow rate of shell solution form 0.8 mm·min-1 to 1.4 mm·min-1 resulted in an increase in fiber diameter from 4.8 μm to 15.3 μm, and an increase in pore size from 59.4 nm to 305.6 nm. Due to the high enthalpy and coverage of the PEG core, the PLA/PEG fibermats exhibited excellent thermal-regulation performance, with a surface temperature that was 2.5 °C- 5.6 °C lower than that of pure PLA fibermat during heating process. On-demand release was achieved by directly controlling the core layer of the coaxial PLA/PEG fiber through temperature. The hydrophobicity of the PLA shell initially reduced burst release, followed by increased release as the temperature reached the phase transition temperature of PEG. Furthermore, this advanced fibermat demonstrated desirable moisture permeability, appropriate mechanical properties and good thermal stability, indicating broad potential applications in medical and health fields.

Impact of concentration polarization on the performance of membrane gas separation processes: application to biogas upgrading

Through the illustrative application of biogas treatment, this paper investigates the impact of concentration polarization on the separation performance of emerging inorganic membranes in membrane gas separation processes. The results show that polarization may significantly reduce the biogas purification rate, although its effects on methane recovery remain moderate. Contrary to previous assumptions, the impact of polarization does not monotonously increase with increasing permeance to CO2 and selectivity. Material selectivity is shown to not significantly influence the polarization intensity, and the CO2 permeance at which peak polarization conditions occur is not constant but varies depending on the operating and geometric conditions considered. The impact of polarization impact intensifies with increasing fiber diameter and operating pressure, preventing taking full advantage of the exceptional permeances of inorganic membranes, and therefore, constitutes a major obstacle to their use as an alternative to conventional polymeric fibers.

A polynomial temperature profile model for suspended droplet evaporation over a wide range of ambient pressures and convection conditions

The suspended droplet technique has been widely applied in experimental droplet evaporation studies, but heat conduction caused by support fiber can change the evaporation characteristics. In the present study, a novel theoretical model is proposed to investigate the effect of a suspender on droplet heating and evaporation. Considering the vortex circulation inside the droplet and the heat diffusion along the support fiber, the temperature distribution is assumed to exhibit a polynomial profile. The effects of pressure on the thermodynamic and transport properties are also accounted for. The simulation results are consistent with previous experimental data over a wide range of ambient pressures and convection conditions. The performance of the new model is further compared with that of other models in terms of computational efficiency and accuracy. The new model requires an order of magnitude less CPU time than does the effective thermal conductivity model to preserve the key features of the temperature distribution accurately. In addition, a dual effect of the fiber diameter on the evaporation rate is demonstrated. With increasing fiber diameter, the evaporation rate increases and then decreases. There are two different patterns that can depict heat transfer between the suspended droplets and the fibers: an “immersed area pattern” and a “fiber temperature pattern”. A switchover in the two patterns is responsible for the dual effect, which occurs at a threshold fiber diameter related to the environment.

Influence of Fiber Dimensions on Bridging Performance of Polyvinyl Alcohol Fiber-Reinforced Cementitious Composite (PVA-FRCC)

This study investigates the influence of fiber dimensions on the bridging performance of polyvinyl alcohol fiber-reinforced cementitious composite (PVA-FRCC) through an experimental and analytical program. Bending tests, bridging law calculations, and section analysis are conducted. Bending tests of notched specimens of PVA-FRCC with six different PVA fiber dimensions are performed to determine the load–deflection (LPD) and bending moment–crack mouth opening displacement (CMOD) relationships. The fiber volume fraction for all PVA-FRCCs is set to 2%. It is found that the load capacity of PVA-FRCC with a 27 μm diameter fiber is much higher than that of the other fibers, and the load capacity decreases as the fiber diameter increases. The study proposes parameters for the characteristic points of the tri-linear model for the single-fiber pullout model as functions of diameter, bond fracture energy, elastic modulus, cross-sectional area, and perimeter of the fiber. These findings provide valuable insights into the behavior of PVA-FRCC under different fiber dimensions. Bridging law calculations are conducted to obtain tensile stress–crack width relationships using the developed single-fiber pullout models. The Popovics model for the complete tensile stress–crack width relationship is adopted to obtain a better fit with the bridging law calculation, and then section analysis is conducted. The bridging law calculation results show that the maximum tensile stress decreases as the fiber diameter increases. It is also determined that most of the smaller-diameter fibers ruptured, whereas the larger fiber diameters pulled out from the matrix. The section analysis results show good agreement with the maximum bending moments obtained from the bending test.

Cascaded geometric parametric process in a tapered air-silica graded-like multimode microstructure fiber.

We experimentally study the spatial beam profile and the spectral broadening at the output of a multimode air-silica microstructure fiber taper, used along the direction of an increasing fiber diameter. By using a laser pump at 1064 nm emitting 60 ps Gaussian beam pulses, we observed a competition between Raman beam cleanup and Kerr beam self-cleaning: the multimode frequency conversion process permits to generate spectral sidebands with frequency detuning from the pump that are difficult to obtain in standard graded-index multimode fibers. The generated supercontinuum spans from 500 nm up to 2.5 µm.

Enhancing therapeutic potential: Human adipose-derived mesenchymal stem cells modified with recombinant adeno-associated virus expressing VEGF165 gene for peripheral nerve injury.

This study aimed to investigate the therapeutic potential of human adipose-derived mesenchymal stem cells (hADSCs) modified with recombinant adeno-associated virus (rAAV) carrying the vascular endothelial growth factor 165 (VEGF165) gene in peripheral nerve injury (PNI). The hADSCs were categorized into blank, control (transduced with rAAV control vector), and VEGF165 (transduced with rAAV VEGF165 vector) groups. Subsequently, Schwann cell differentiation was induced, and Schwann cell markers were assessed. The sciatic nerve injury mouse model received injections of phosphate-buffered saline (PBS group), PBS containing hADSCs (hADSCs group), rAAV control vector (control-hADSCs group), or rAAV VEGF165 vector (VEGF165-hADSCs group) into the nerve defect site. Motor function recovery, evaluated through the sciatic function index (SFI), and nerve regeneration, assessed via toluidine blue staining along with scrutiny of Schwann cell markers and neurotrophic factors, were conducted. Modified hADSCs exhibited enhanced Schwann cell differentiation and elevated expression of Schwann cell markers [S100 calcium-binding protein B (S100B), NGF receptor (NGFR), and glial fibrillary acidic protein (GFAP)]. Mice in the VEGF165-hADSCs group demonstrated improved motor function recovery compared to those in the other three groups, accompanied by increased fiber diameter, axon diameter, and myelin thickness, as well as elevated expression of Schwann cell markers (S100B, NGFR, and GFAP) and neurotrophic factors [mature brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF)] in the distal nerve segment. rAAV-VEGF165 modification enhances hADSC potential in PNI, promoting motor recovery and nerve regeneration. Elevated Schwann cell markers and neurotrophic factors underscore therapy benefits, providing insights for nerve injury strategies.

Bifunctional naringenin-laden gelatin methacryloyl scaffolds with osteogenic and anti-inflammatory properties

ObjectiveTo fabricate and characterize an innovative gelatin methacryloyl/GelMA electrospun scaffold containing the citrus flavonoid naringenin/NA with osteogenic and anti-inflammatory properties. MethodsGelMA scaffolds (15 % w/v) containing 0/Control, 5, 10, or 20 % of NA w/w were obtained via electrospinning. The chemical composition, fiber morphology/diameter, swelling/degradation profile, and NA release were investigated. Cytotoxicity, cell proliferation, adhesion and spreading, total protein/TP production, alkaline phosphatase/ALP activity, osteogenic genes expression (OCN, OPN, RUNX2), and mineralized nodules deposition/MND with human alveolar bone-derived mesenchymal stem cells (aBMSCs) seeded on the scaffolds were assessed. Moreover, aBMSCs seeded on the scaffolds and stimulated with tumor necrosis factor-alpha/TNF-α were submitted to collagen, nitric oxide/NO, interleukin/IL-1α, and IL-6 production assessment. Data were analyzed using ANOVA and t-student/post-hoc tests (α = 5 %). ResultsNA-laden scaffolds presented increased fiber diameter, lower swelling capacity, and faster degradation profile over 28 days (p < 0.05). NA release was detected over time. Cell adhesion and spreading, and TP production were similar between GelMA and GelMA+NA5 % scaffolds, while cell proliferation, ALP activity, OCN/OPN/RUNX2 gene expression, and MND were higher for GelMA+NA5 % scaffolds (p < 0.05). Cells seeded on control scaffolds and TNF-α-stimulated presented higher levels of NO, IL-1α/IL-6, and lower levels of collagen (p < 0.05). In contrast, cells seeded on GelMA+NA5 % scaffolds showed downregulation of inflammatory markers and higher collagen synthesis (p < 0.05). SignificanceGelMA+NA5 % scaffold was cytocompatible, stimulated aBMSCs proliferation and differentiation, and downregulated inflammatory mediators’ synthesis, suggesting its therapeutic effect as a multi-target bifunctional scaffold with osteogenic and anti-inflammatory properties for bone tissue engineering.

Characterization of Blow-Spun Polyurethane Scaffolds-Influence of Fiber Alignment and Fiber Diameter on Pericyte Growth.

In this study, fibrous polyurethane (PU) materials with average fiber diameter of 200, 500, and 1000 nm were produced using a solution blow spinning (SBS) process. The effects of the rotation speed of the collector (in the range of 200-25 000 rpm) on the fiber alignment and diameter were investigated. The results showed that fiber alignment was influenced by the rotation speed of the collector, and such alignment was possible when the fiber diameter was within a specific range. Homogeneously oriented fibers were obtained only for a fiber diameter ≥500 nm. Moreover, the changes in fiber orientation and fiber diameter (resulting from changes in the rotation speed of the collector) were more noticeable for materials with an average fiber diameter of 1000 nm in comparison to 500 nm, which suggests that the larger the fiber diameter, the better the controlled architectures that can be obtained. The porosity of the produced scaffolds was about 65-70%, except for materials with a fiber diameter of 1000 nm and aligned fibers, which had a higher porosity (76%). Thus, the scaffold pore size increased with increasing fiber diameter but decreased with increasing fiber alignment. The mechanical properties of fibrous materials strongly depend on the direction of stretching, whereby the fiber orientation influences the mechanical strength only for materials with a fiber diameter of 1000 nm. Furthermore, the fiber diameter and alignment affected the pericyte growth. Significant differences in cell growth were observed after 7 days of cell culture between materials with a fiber diameter of 1000 nm (cell coverage 96-99%) and those with a fiber diameter of 500 nm (cell coverage 70-90%). By appropriately setting the SBS process parameters, scaffolds can be easily adapted to the cell requirements, which is of great importance in producing complex 3D structures for guided tissue regeneration.

Lactobacillus-derived protoporphyrin IX and SCFAs regulate the fiber size via glucose metabolism in the skeletal muscle of chickens.

The gut microbiota contributes to skeletal muscle energy metabolism and is an indirect factor affecting meat quality. However, the role of specific gut microbes in energy metabolism and fiber size of skeletal muscle in chickens remains largely unknown. In this study, we first performed cecal microbiota transplantation from Chinese indigenous Jingyuan chickens (JY) to Arbor Acres chickens (AA), to determine the effects of microbiota on skeletal muscle fiber and energy metabolism. Then, we used metagenomics, gas chromatography, and metabolomics analysis to identify functional microbes. Finally, we validated the role of these functional microbes in regulating the fiber size via glucose metabolism in the skeletal muscle of chickens through feeding experiments. The results showed that the skeletal muscle characteristics of AA after microbiota transplantation tended to be consistent with that of JY, as the fiber diameter was significantly increased, and glucose metabolism level was significantly enhanced in the pectoralis muscle. L. plantarum, L. ingluviei, L. salivarius, and their mixture could increase the production of the microbial metabolites protoporphyrin IX and short-chain fatty acids, therefore increasing the expression levels of genes related to the oxidative fiber type (MyHC SM and MyHC FRM), mitochondrial function (Tfam and CoxVa), and glucose metabolism (PFK, PK, PDH, IDH, and SDH), thereby increasing the fiber diameter and density. These three Lactobacillus species could be promising probiotics to improve the meat quality of chicken.IMPORTANCEThis study revealed that the L. plantarum, L. ingluviei, and L. salivarius could enhance the production of protoporphyrin IX and short-chain fatty acids in the cecum of chickens, improving glucose metabolism, and finally cause the increase in fiber diameter and density of skeletal muscle. These three microbes could be potential probiotic candidates to regulate glucose metabolism in skeletal muscle to improve the meat quality of chicken in broiler production.

Enhancing 3D poly[ɛ]caprolactone scaffold properties through alkaline hydrolysis for improved chondrocyte culture: Morphological, physicochemical, and biocompatibility evaluations

This study investigates the impact of alkaline hydrolysis on the morphology, physicochemical properties, and mechanical strength of poly[ε]caprolactone (PCL) scaffolds fabricated using a melt-based electrohydrodynamic process. We systematically analyzed how a brief, 5-min alkaline hydrolysis treatment influenced scaffold characteristics compared to longer durations (15 and 30 min). Results demonstrated that the short-duration treatment significantly increased fiber diameter and reduced pore size while modifying the scaffold's surface chemistry. Importantly, the 5-min treatment optimized the water contact angle to 55–65°, enhancing hydrophilicity which facilitated superior cell attachment and proliferation of the C28/I2 immortalized human chondrocyte cell line. Mechanical testing revealed that while alkaline hydrolysis decreased the scaffold's Young's modulus, a 5-min treatment maintained sufficient mechanical integrity for potential tissue engineering applications, in contrast to the more substantial degradation observed with longer treatments.Biocompatibility evaluations showed that the scaffolds, particularly those treated for 5 min, supported cell viability and proliferation without inducing cytotoxic effects. The molecular analysis indicated a favorable upregulation of chondrogenic genes such as SOX9 and COL2A1, and a downregulation of COL1A1, suggesting potential benefits for cartilage tissue engineering. These findings highlight that precise control over the duration of alkaline hydrolysis can significantly enhance PCL scaffold properties, suggesting a scalable and cost-effective method for scaffold optimization in regenerative medicine applications. The results pave the way for further in vivo studies to validate these promising in vitro findings and explore the clinical applicability of the optimized scaffolds.

In situ densification and heparin immobilization of bacterial cellulose vascular patch for potential vascular applications

Nowadays, developing vascular grafts (e.g., vascular patches and tubular grafts) is challenging. Bacterial cellulose (BC) with 3D fibrous network has been widely investigated for vascular applications. In this work, different from BC vascular patch cultured with the routine culture medium, dopamine (DA)-containing culture medium is employed to in situ synthesize dense BC fibrous structure with significantly increased fiber diameter and density. Simultaneously, BC fibers are modified by DA during in situ synthesis process. Then DA on BC fibers can self-polymerize into polydopamine (PDA) accompanied with the removal of bacteria in NaOH solution, obtaining PDA-modified dense BC (PDBC) vascular patch. Heparin (Hep) is subsequently covalently immobilized on PDBC fibers to form Hep-immobilized PDBC (Hep@PDBC) vascular patch. The obtained results indicate that Hep@PDBC vascular patch exhibits remarkable tensile and burst strength due to its dense fibrous structure. More importantly, compared with BC and PDBC vascular patches, Hep@PDBC vascular patch not only displays reduced platelet adhesion and improved anticoagulation activity, but also promotes the proliferation, adhesion, spreading, and protein expression of human umbilical vein endothelial cells, contributing to the endothelialization process. The combined strategy of in situ densification and Hep immobilization provides a feasible guidance for the construction of BC-based vascular patches.

An in vitro and in vivo study of electrospun polyvinyl alcohol/chitosan/sildenafil citrate mat on 3D-printed polycaprolactone membrane as a double layer wound dressing

Double-layer dermal substitutes (DS) generally provide more effective therapeutic outcomes than single-layer substitutes. The architectural design of DS incorporates an outer layer to protect against bacterial invasions and maintain wound hydration, thereby reducing the risk of infection and the frequency of dressing changes. Moreover, the outer layer is a mechanical support for the wound, preventing undue tension in the affected area. A 3D-printed polycaprolactone (PCL) membrane was utilized as the outer layer to fabricate DS wound dressing. Simultaneously, a polyvinyl alcohol/chitosan/sildenafil citrate (PVA/CS/SC) scaffold was electrospun onto the PCL membrane to facilitate cellular adhesion and proliferation. Scanning electron microscopy (SEM) analysis of the PCL filaments revealed a consistent cross-sectional surface and structure, with an average diameter of 562.72 ± 29.15 μm. SEM results also demonstrated uniform morphology and beadless structure for the PVA/CS/SC scaffold, with an average fiber diameter of 366.77 ± 1.81 nm for PVA/CS. The addition of SC led to an increase in fiber diameter while resulting in a reduction in tensile strength. However, drug release analysis indicated that the SC release from the sample can last up to 72 h. Animal experimentation confirmed that DS wound dressing positively accelerated wound closure and collagen deposition in the Wistar rat skin wound model.

Structural and sound absorption properties of polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) nanofibers

Sound-absorbing materials are used to reduce noise pollution since noise is one of the important environmental factors affecting human health. Due to their high porosity and large specific surface area, nanofibers can be preferred as a better sound absorption material. In this study, nanofiber-based sound-absorbing materials are produced using polyethylene terephthalate (PET) and recycled polyethylene terephthalate (r-PET) in the electrospinning method in order to obtain a thin and high-sound absorbing material. Another objective of this study is to investigate the performance of r-PET compared to PET from the sound absorbing properties points of view to contribute sustainability which is one of the most important issues of today. For these purposes, solutions of three different concentrations (10%, 15% and 20% owf) were prepared by dissolving PET and r-PET polymers in trifluoroacetic acid (TFA):dichloromethane (DCM) solvent mixture. It will also be possible to help sustainability issues by reducing environmental pollution and raw material costs by using r-PET. Samples were electrospun on a polypropylene based nonwoven structure using solutions at different flow rates (0.1-0.3-0.5 ml/h) and needle tip-collector distances (4–8 cm). The fiber diameter, thickness, bulk density, porosity and pore size properties of the produced samples were investigated. The sound absorption coefficient (SAC) was measured with a dual microphone impedance tube device. The relationship between the structural properties of the samples and the SAC was evaluated. SAC decreased with increasing fiber diameter, bulk density, pore size and increased with high porosity. These values were compared with different sound absorbing materials which are commonly used. According to the results, the developed nanofiber-based material with a 0.3 mm thickness has high SAC values compared to conventional sound absorbing materials with 10–16 mm thickness values, especially in middle frequency levels. Recycled polymer may be preferred when PET and r-PET nanofibers show similar results.

Skeletal muscle ULK1 and ULK2 modulate protein synthesis impacting fiber size

Maintenance of skeletal muscle homeostasis is largely influenced by the processes of protein synthesis and degradation. However, the regulation of these processes remains incompletely understood particularly in a tissue or cell type-specific manner. We have previously demonstrated that Unc-51 like autophagy activating kinases 1 and 2 (Ulk1/2) are among the top 5 mostly enriched putative autophagy genes in skeletal muscle when compared to &gt;90 other mouse tissues and cell lines (Fuqua et al., FASEB J, 2019). However, because protein kinases commonly have several downstream targets, here we hypothesized that skeletal muscle ULK1 and ULK2 redundantly modulate other important cellular processes. To begin to address this question, we generated mice with skeletal muscle-specific knockout of ULK1 and ULK2 (i.e., ULK1/2 skmDKO) and studied those at different ages. Muscle basal autophagy flux was impaired in ULK1/2 skmDKO mice. However, contrary to other models of autophagy impairment, which commonly leads to muscle atrophy, adult ULK1/2 skmDKO mice had increased muscle size (15-25%, P≤0.01). Hypertrophy occurred in all fiber types (6-20% increase in fiber diameter, P≤0.05) and in response to an acute (4-week) deficiency of ULK1/2 (via electroporations of plasmids encoding ULK1/2miR), where TA fiber diameter increased by 9% (p&lt;0.05). Further studies using D2O labeling and cellular fractionation revealed that ULK1/2 skmDKO mice have increased myofibrillar protein synthesis rates (~5%/day, p&lt;0.05). Examination of the molecular mechanisms involved suggests that ULK1/2 skmDKO mice have enhanced mTORC1-dependent signaling, particularly in the fed state. Altogether, our findings reveal for the first time that ULK1 and ULK2 collectively stimulate protein degradation and inhibit protein synthesis in skeletal muscle potentially impacting muscle mass and function in conditions of muscle atrophy and hypertrophy. Supported by the University of Iowa Fraternal Order of Eagles Diabetes Research Center (UIowa FOEDRC). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Functionalization of PCL-Based Fiber Scaffolds with Different Sources of Calcium and Phosphate and Odontogenic Potential on Human Dental Pulp Cells.

This study investigated the incorporation of sources of calcium, phosphate, or both into electrospun scaffolds and evaluated their bioactivity on human dental pulp cells (HDPCs). Additionally, scaffolds incorporated with calcium hydroxide (CH) were characterized for degradation, calcium release, and odontogenic differentiation by HDPCs. Polycaprolactone (PCL) was electrospun with or without 0.5% w/v of calcium hydroxide (PCL + CH), nano-hydroxyapatite (PCL + nHA), or β-glycerophosphate (PCL + βGP). SEM/EDS analysis confirmed fibrillar morphology and particle incorporation. HDPCs were cultured on the scaffolds to assess cell viability, adhesion, spreading, and mineralized matrix formation. PCL + CH was also evaluated for gene expression of odontogenic markers (RT-qPCR). Data were submitted to ANOVA and Student's t-test (α = 5%). Added CH increased fiber diameter and interfibrillar spacing, whereas βGP decreased both. PCL + CH and PCL + nHA improved HDPC viability, adhesion, and proliferation. Mineralization was increased eightfold with PCL + CH. Scaffolds containing CH gradually degraded over six months, with calcium release within the first 140 days. CH incorporation upregulated DSPP and DMP1 expression after 7 and 14 days. In conclusion, CH- and nHA-laden PCL fiber scaffolds were cytocompatible and promoted HDPC adhesion, proliferation, and mineralized matrix deposition. PCL + CH scaffolds exhibit a slow degradation profile, providing sustained calcium release and stimulating HDPCs to upregulate odontogenesis marker genes.

Characterization of Nanoporous Poly(Lactic Acid) Microfibers Using a Simplified Centrifugal Spinning Method

In recent years, great attention has been paid to the development of porous materials with excellent reactivity and absorbency. The poly(lactic acid) (PLA) microfibers with uniform nanopores were successfully prepared by rotary centrifugal spinning using PLA/chloroform solution. Previous research showed that PLA microfibers have extremely high oil absorbing capacity. In this study, the changes in fiber diameter and nanopore diameter of nanoporous PLA microfibers under different fabrication conditions and the adsorption capacity of Prussian blue nanoparticles were systematically evaluated. The results showed that the fiber diameter increased with increasing PLA/chloroform solution concentration. Furthermore, it was found that the amount of adsorbed Prussian blue nanoparticles increased with the increase in fiber diameter. Prussian blue nanoparticles are known to adsorb radioactive materials such as cesium, and are expected to be applied to the recovery of cesium diffused in the atmosphere and ocean.

Preparation of PEI/La2O3/Polypropylene fiber filter for household water purifiers and investigation of its phosphate reduction and bacterial control

It has been accepted that limiting phosphate is a prerequisite for bacterial inactivation in tap water. La2O3 nanoparticles were loaded onto polypropylene (PP) fibers through the method of melt spinning. Hydrophilic modification of the adsorbent surface was performed using polyethyleneimine (PEI) to prepare PEI/La2O3/PP. The results indicated that the optimal loading amount of La2O3 was 1 %, and the optimal concentration of PEI was 1 %. The successful loading of La2O3 resulted in a roughened fiber surface and increased fiber diameters. After PEI modification the water contact angle was reduced from 98° to 50°. The pHzpc of PEI/La2O3/PP was determined to be 8.3. The co-existing ions have little effect on phosphate adsorption. Phosphate adsorption can be well described by Redlich-Peterson model with a maximum KR-P of 3.98 × 10−5 L/mg. Adsorption kinetics fit well with the pseudo-second-order reaction equation. The activation energy (Ea) is determined to be 57.9 kJ/mol, providing the evidence of chemical nature of the reaction involving phosphate ions on the surface of PEI/La2O3/PP. The PEI/La2O3/PP adsorbent can reduce the phosphate concentration in tap water to below 0.01 mg/L, leading to a reduction in Escherichia coli concentration from approximately 10,000 CFU/mL to around 10 CFU/mL. The survival rates of Escherichia coli in a multi-nutrient environment are higher than in a single phosphate source environment. Our research provides a new feasible approach for ensuring microbial water quality safety in household water purifiers.