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1.
Protein Sci ; 33(8): e5107, 2024 Aug.
Article de Anglais | MEDLINE | ID: mdl-38989549

RÉSUMÉ

Interactions between proteins and osmolytes are ubiquitous within cells, assisting in response to environmental stresses. However, our understanding of protein-osmolyte interactions underlying desiccation tolerance is limited. Here, we employ solid-state NMR (ssNMR) to derive information about protein conformation and site-specific interactions between the model protein, SH3, and the osmolyte trimethylamine N-oxide (TMAO). The data show that SH3-TMAO interactions maintain key structured regions during desiccation and facilitate reversion to the protein's native state once desiccation stress is even slightly relieved. We identify 10 types of residues at 28 sites involved in the SH3-TMAO interactions. These sites comprise hydrophobic, positively charged, and aromatic amino acids located in SH3's hydrophobic core and surface clusters. TMAO locks both the hydrophobic core and surface clusters through its zwitterionic and trimethyl ends. This double locking is responsible for desiccation tolerance and differs from ideas based on exclusion, vitrification, and water replacement. ssNMR is a powerful tool for deepening our understanding of extremely weak protein-osmolyte interactions and providing insight into the evolutionary mechanism of environmental tolerance.


Sujet(s)
Dessiccation , Interactions hydrophobes et hydrophiles , Méthylamines , Méthylamines/composition chimique , Résonance magnétique nucléaire biomoléculaire , Modèles moléculaires , Conformation des protéines
2.
ACS Nano ; 2024 Jul 11.
Article de Anglais | MEDLINE | ID: mdl-38989607

RÉSUMÉ

Lewis base molecules bind the undercoordinated lead atoms at interfaces and grain boundaries, leading to the high efficiency and stability of flexible perovskite solar cells (PSCs). We demonstrated a highly efficient, stable, and flexible PSC via interface passivation using a Lewis base of tri(o-tolyl)phosphine (TTP). It not only induced an intimate interface contact and a complete deposition of the perovskite thin layers on hole transport layers (HTLs) but also led to a better perovskite with a raised crystallinity, fewer defects, and a better morphology, including fewer gullies, high uniformity, and low roughness. Furthermore, the TTP treatments induced a good alignment of energy levels among the perovskites, HTLs, and C60. The resultant flexible inverted PSCs exhibited a high power conversion efficiency (PCE) of 23.81%, which is one of the highest PCEs among these flexible inverted PSCs. Moreover, the optimized flexible PSCs exhibited high storage stability, superior operation stability, and enhanced mechanical flexibility. This study presents an effective method to substantially raise the PCE, stability, and mechanical flexibility of the flexible inverted perovskite photovoltaics.

3.
J Sci Food Agric ; 2024 Jul 11.
Article de Anglais | MEDLINE | ID: mdl-38989609

RÉSUMÉ

BACKGROUND: Algae oil has garnered widespread acclaim due as a result of its high purity of docosahexaenoic acid (DHA) and excellent safety profile. The present study aimed to develop stable nanoemulsions (NEs) systems containing DHA from algae oil through thermal sterilization by combining modified whey protein concentrate (WPC) with low methoxyl pectin (LMP), as well as to investigate the impact of LMP concentration on the thermal stability and the gastrointestinal delivery efficiency of DHA NEs. RESULTS: The addition of LMP enhanced the stability of the emulsion after sterilization, at the same time as improving the protective and sustained release effects of DHA in the gastrointestinal tract. Optimal effect was achieved at a LMP concentration of 1% (10 g kg-1 sample), the stability of the emulsion after centrifugation increased by 17.21 ± 5.65% compared to the group without LMP, and the loss of DHA after sterilization decreased by only 0.92 ± 0.09%. Furthermore, the addition of 1% LMP resulted in a substantial reduction in the release of fatty acids from the NEs after gastrointestinal digestion simulation, achieving the desired sustained-release effect. However, excessive addition of 2% (20 g kg-1 sample) LMP negatively impacted all aspects of the NEs system, primarily because of the occurrence of depletion effects. CONCLUSION: The construction of the LMP/WPC-NEs system is conducive to the protection of DHA in algae oil and its sustained-release in the gastrointestinal tract. The results of the present study can provide reference guidance for the application of algae oil NEs in the food field. © 2024 Society of Chemical Industry.

4.
Small ; : e2400641, 2024 Jul 11.
Article de Anglais | MEDLINE | ID: mdl-38989690

RÉSUMÉ

Li-rich manganese-based cathode (LRMC) has attracted intense attention to developing advanced lithium-ion batteries with high energy density. However, LRMC is still plagued by poor cyclic stability, undesired rate capacity, and irreversible oxygen release. To address these issues, herein, a feasible polyvinylidene fluoride (PVDF)-assisted interface modification strategy is proposed for modulating the surface architecture and electronic conductivity of LRMC by intruding the F-doped carbon coating, spinel structure, and oxygen vacancy on the LRMC, which can greatly enhance the cyclic stability and rate capacity, and restrain the oxygen release for LRMC. As a result, the modified material delivers satisfactory cyclic performance with a capacity retention of 90.22% after 200 cycles at 1 C, an enhanced rate capacity of 153.58 mAh g-1 at 5 C and 126.32 mAh g-1 at 10 C, and an elevated initial Coulombic efficiency of 85.63%. Moreover, the thermal stability, electronic conductivity, and structure stability of LRMC are also significantly improved by the PVDF-assisted interface modification strategy. Therefore, the strategy of simultaneously modulating the surface architecture and the electronic conductivity of LRMC provides a valuable idea to improve the comprehensive electrochemical performance of LRMC, which offers a promising reference for designing LRMC with high electrochemical performance.

5.
Small ; : e2402114, 2024 Jul 11.
Article de Anglais | MEDLINE | ID: mdl-38989698

RÉSUMÉ

Designing effective antifog coatings poses challenges in resisting physical and chemical damage, with persistent susceptibility to decomposition in aggressive environments. As their robustness is dictated by physicochemical structural features, precise control through unique fabrication strategies is crucial. To address this challenge, a novel method for crafting nanoscale antifog films with simultaneous directional growth and cross-linking is presented, utilizing solid-state continuous assembly of polymers via ring-opening metathesis polymerization (ssCAPROMP). A new amphiphilic copolymer (specified as macrocross-linker) is designed by incorporating polydimethylsiloxane, poly(2-(methacryloyloxy)ethyl) trimethylammonium chloride (PMETAC), and polymerizable norbornene (NB) pendant groups, allowing ssCAPROMP to produce antifog films under ambient conditions. This novel approach results in distinctive surface and molecular characteristics. Adjusting water-absorption and nanoscale assembly parameters produced ultra-thin (≤100 nm) antifog films with enhanced durability, particularly against strong acidic and alkaline environments, surpassing commercial antifog glasses. Thickness loss analysis against external disturbances further validated the stable surface-tethered chemistries introduced through ssCAPROMP, even with the incorporation of minimal content of cross-linkable NB moieties (5 mol%). Additionally, a potential zwitter-wettability mechanism elucidates antifog observations. This work establishes a unique avenue for exploring nanoengineered antifog coatings through facile and robust surface chemistries.

6.
Attach Hum Dev ; 26(3): 233-252, 2024 Jun.
Article de Anglais | MEDLINE | ID: mdl-38989771

RÉSUMÉ

This study examined the stability of Attachment Script Assessment (ASA) deactivation, hyperactivation, and anomalous content and their significance for parenting outcomes in mothers (Mage = 31 years; 78% White/European American) and 6-month-old infants. Comparable to ASA secure base script knowledge (SBSK), mothers' ASA deactivation, hyperactivation, and anomalous content were significantly, moderately stable over two years (r's = .40 - .43). Mothers' ASA hyperactivation and anomalous content were associated with greater maternal intrusiveness, whereas ASA deactivation was associated with greater detachment and less intrusiveness. Only ASA anomalous content was associated with lower maternal sensitivity. Mothers' ASA deactivation was associated with less dynamic change in respiratory sinus arrhythmia during the Still-Face Procedure-reflective of limited mobilization of physiological resources to support responding to infants. Findings support the validity of ASA deactivation, hyperactivation, and anomalous content scripts, and demonstrate their utility in examining adult attachment stability and predictive significance for parent-child outcomes.


Sujet(s)
Relations mère-enfant , Attachement à l'objet , Pratiques éducatives parentales , Humains , Femelle , Nourrisson , Relations mère-enfant/psychologie , Adulte , Pratiques éducatives parentales/psychologie , Mâle , Mères/psychologie , Comportement maternel/psychologie , Arythmie sinusale respiratoire/physiologie
7.
Cell Rep ; 43(7): 114419, 2024 Jul 08.
Article de Anglais | MEDLINE | ID: mdl-38985672

RÉSUMÉ

The compaction of chromatin into mitotic chromosomes is essential for faithful transmission of the genome during cell division. In eukaryotes, chromosome morphogenesis is regulated by the condensin complex, though the exact mechanism used to target condensin to chromatin and initiate condensation is not understood. Here, we reveal that condensin contains an intrinsically disordered region (IDR) that modulates its association with chromatin in early mitosis and exhibits phase separation. We describe DNA-binding motifs within the IDR that, upon deletion, inflict striking defects in chromosome condensation and segregation, ill-timed condensin turnover on chromatin, and cell death. Importantly, we demonstrate that the condensin IDR can impart cell cycle regulatory functions when transferred to other subunits within the complex, indicating its autonomous nature. Collectively, our study unveils the molecular basis for the initiation of chromosome condensation in early mitosis and how this process ultimately promotes genomic stability and faultless cell division.

8.
Int J Biol Macromol ; 275(Pt 1): 133454, 2024 Jul 02.
Article de Anglais | MEDLINE | ID: mdl-38964692

RÉSUMÉ

In the realization of the goal of circular economy, cellulose as one of sustainable biomass resources, have attracted much attention because of their abundant sources, biodegradability and renewability. However, the mechanical and waterproof performance of cellulose-based materials are usually not satisfying, which limits their high-value utilization. In this study, cellulose membrane with high-performance from the aspects of mechanical properties, water-resistance ability, oxygen barrier capacity and biodegradability, was prepared from bleached hardwood pulp (HBKP) in a AlCl3/ZnCl2/H2O solution. The AlCl3/ZnCl2/H2O acted as both solvent and catalyst to dissolve cellulose and facilitate the chemical crosslinking of epichlorohydrin (EPI) with cellulose, thus improved the overall performance of the obtained cellulose membrane. The addition sequence, amount and crosslinking time of EPI during chemical crosslinking had important effects on the properties of the membranes. When 7 wt% EPI was crosslinked for 24 h, the tensile stress reached 133 MPa and the strain reached 17 %. Moreover, the membrane had excellent oxygen insulation down to (1.1 ± 0.31) × 10-4 cm3/m2·d·Pa, and good water-resistance ability, no obvious swelling behavior after 450 days of immersion in distilled water. Furthermore, the membrane could be degraded by microorganisms in about 20 days. This cellulose-based membrane offers a sustainable and biodegradable packaging material.

9.
Behav Anal Pract ; 17(2): 500-513, 2024 Jun.
Article de Anglais | MEDLINE | ID: mdl-38966265

RÉSUMÉ

Characteristics of emotional and behavioral disorders (EBD) include learning difficulties that cannot be explained by intellectual, sensory, or health factors and difficulties in building or maintaining interpersonal relationships with peers and teachers. Children with or at risk for an EBD often have a tendency to have negative experiences in school and engage in challenging behavior in the classroom including out-of-seat behavior. One possible antecedent manipulation, alternative seating, may reduce challenging behavior and involves exchanging the typical seating in classrooms for different types of seating options. The purpose of this study was to evaluate the use of stability stools and scoop rocker chairs on in-seat behavior and on-task behavior in classrooms with kindergarten students who engaged in challenging behavior and were at risk for EBD. All three participants demonstrated improvements in in-seat behavior using both types of alternative seating compared to a standard classroom chair. On-task behavior improved for all students but was variable for two students. Teachers indicated a preference for the stability stool, whereas results were mixed between the stool and the rockers for student preference.

10.
Front Psychol ; 15: 1297058, 2024.
Article de Anglais | MEDLINE | ID: mdl-38966721

RÉSUMÉ

Dishonesty, including lying, cheating, deception, and deviating from societal norms, has far-reaching implications across various aspects of modern society. From minor consequences like social discontent to severe outcomes such as economic damage through tax evasion, dishonest behavior affects us in multiple ways. This study investigates whether gender and psychological traits contribute to dishonest behavior, and whether unethical conduct is stable across diverse tasks. We examined 63 participants using a "Difference Spotting Task" (DST) and two motor tasks (1. coordinative throwing; 2. isometric strength). Dishonesty was measured by comparing self-reported performance with actual performance, allowing for a comprehensive analysis of both occurrence and extent of dishonesty. Our findings indicate that gender does not significantly influence the occurrence or extent of dishonest behavior. Moreover, we discovered that "Social Desirability" positively influences the extent of dishonesty, while "Task Orientation" increases the likelihood of engaging in dishonest acts. The study also reveals that the level of dishonesty remains relatively stable across all three tasks at an intrapersonal level.

11.
Front Psychol ; 15: 1379651, 2024.
Article de Anglais | MEDLINE | ID: mdl-38966735

RÉSUMÉ

Objective: The aims of this study were to examine changes in habitual optimism over a six-year period and to analyze the relationship between changes in optimism and changes in other quality of life-related variables. Method: A randomly selected community sample of the German adult general population (N = 4,965) was surveyed twice, with a time interval of 6.04 years. Results: During the course of the 6 years, the mean score of the LOT-R total scale improved (effect size d = 0.11). The temporal stability in terms of the test-retest correlation was r = 0.61 for the total sample. There were only marginal gender differences in this temporal stability, however, the stability in the oldest age group ≥70 years (r = 0.50) was lower than the stability of the other age groups. The cross-sectional correlations showed clear relationships between optimism on the one hand and quality of life, life satisfaction, social support, and low levels of anxiety and physical complaints on the other. The corresponding longitudinal correlations between changes in optimism and changes in the other variables were less pronounced, but in the same direction. Conclusion: The study confirmed the applicability of the LOT-R in longitudinal studies. In samples with participants of 70 years and above, the limited stability in the optimism assessments needs to be considered in clinical practice and epidemiologic research.

12.
J Food Sci Technol ; 61(8): 1439-1456, 2024 Aug.
Article de Anglais | MEDLINE | ID: mdl-38966796

RÉSUMÉ

Aquafaba is the residual water from cooking chickpea in water. It has a high gelling ability, allowing it to create stable gels. However, those functional properties depend on the legume composition, genotype, cooking time, pressure, and temperature. This study aimed to evaluate the different processes for obtaining aquafaba and compare their nutritional composition and technological characteristics using a systematic review. The authors performed the systematic review by performing specific search strategies for Scopus, Web of Science, Pubmed, Lilacs, Google Scholar, and ProQuest. A total of 17 studies were analyzed. Of them, 17.64% (n = 3) used the wastewater from canned chickpeas, 17.64% (n = 3) compared the wastewater of canned chickpeas and dry grains, and 58.82% (n = 10) used dry chickpeas. Studies used different methods to analyze the protein content. The most used (n = 5) was the Association of Official Analytical Chemists (AOAC). The aquafaba presented carbohydrates at 2.03-2.59 g/100ml; protein at 0.0.8-2.8 g/100ml; and fat at 0.07-0.1 g/100ml. In general, preparing aquafaba followed: soaking (8-10 h at 4 °C-1 chickpea: 4 water), pressure cooking (30 min-2 chickpea: 3 water), and refrigerating (24h/4 °C). In general, the results showed the following steps to prepare aquafaba: soaking for 8-10 h at 4 °C at the proportion of 1:4 (chickpea:water), pressure cooking for 30 min in the proportion of 2:3 (chickpea: water), and refrigerating 24 h/4 °C. These procedures in a homemade aquafaba presented the best results, considering foam development and higher stability. The aquafaba from canned chickpeas has a higher foam-ability and lower emulsion properties than homemade cooking aquafaba. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05920-y.

13.
Proc Natl Acad Sci U S A ; 121(28): e2400084121, 2024 Jul 09.
Article de Anglais | MEDLINE | ID: mdl-38968114

RÉSUMÉ

MXenes have demonstrated potential for various applications owing to their tunable surface chemistry and metallic conductivity. However, high temperatures can accelerate MXene film oxidation in air. Understanding the mechanisms of MXene oxidation at elevated temperatures, which is still limited, is critical in improving their thermal stability for high-temperature applications. Here, we demonstrate that Ti[Formula: see text]C[Formula: see text]T[Formula: see text] MXene monoflakes have exceptional thermal stability at temperatures up to 600[Formula: see text]C in air, while multiflakes readily oxidize in air at 300[Formula: see text]C. Density functional theory calculations indicate that confined water between Ti[Formula: see text]C[Formula: see text]T[Formula: see text] flakes has higher removal energy than surface water and can thus persist to higher temperatures, leading to oxidation. We demonstrate that the amount of confined water correlates with the degree of oxidation in stacked flakes. Confined water can be fully removed by vacuum annealing Ti[Formula: see text]C[Formula: see text]T[Formula: see text] films at 600[Formula: see text]C, resulting in substantial stability improvement in multiflake films (can withstand 600[Formula: see text]C in air). These findings provide fundamental insights into the kinetics of confined water and its role in Ti[Formula: see text]C[Formula: see text]T[Formula: see text] oxidation. This work enables the use of stable monoflake MXenes in high-temperature applications and provides guidelines for proper vacuum annealing of multiflake films to enhance their stability.

14.
Comput Methods Programs Biomed ; 254: 108306, 2024 Jun 28.
Article de Anglais | MEDLINE | ID: mdl-38968828

RÉSUMÉ

BACKGROUND AND OBJECTIVE: Hepatitis virus infections are affecting millions of people worldwide, causing death, disability, and considerable expenditure. Chronic infection with hepatitis C virus (HCV) can cause severe public health problems because of their high prevalence and poor long-term clinical outcomes. Thus a fractional-order epidemic model of the hepatitis C virus involving partial immunity under the influence of memory effect to know the transmission patterns and prevalence of HCV infection is studied. Investigating the transmission dynamics of HCV makes the issue more interesting. The HCV epidemic model and worldwide dynamics are examined in this study. Calculate the basic reproduction number for the HCV model using the next-generation matrix technique. We determine the model's global dynamics using reproduction numbers, the Lyapunov functional approach, and the Routh-Hurwitz criterion. The model's reproduction number shows how the disease progresses. METHODS: A fractional differential equation model of HCV infection has been created. Maximum relevant parameters, such as fractional power, HCV transmission rate, reproduction number, etc., influencing the dynamic process, have been incorporated. The model's numerical solutions are obtained using the fractional Adams method. Finally, numerical simulations support the theoretical conclusions, showing the great agreement between the two. RESULTS: In the fractional-order HCV infection model, the memory effect, which is not seen in the classical model, was shown on graphs so that disease dynamics and vector compartments could be seen. We found that the fractional-order HCV infection model has more stages of freedom than regular derivatives. Fractional-order derivations, which may be the best and most reliable, explained bodily approaches better than classical order. CONCLUSION: The current study modeled and analyzed a fractional-order HCV infection model. The current approach results in a much better understanding of HCV transmission in a population, which leads to important insights into its spread and control, such as better treatment dosage for different age groups, identifying the best control measure, improving health, prolonging life, reducing the risk of HCV transmission, and effectively increasing the quality of life of HCV patients. The creation of a fractional-order HCV infection model, which provides a better understanding of HCV transmission dynamics and leads to significant insights for better treatment dosages, identification of optimal control measures, and ultimately improvement of the quality of life for HCV patients, is the study's major outcome.

15.
Article de Anglais | MEDLINE | ID: mdl-38969008

RÉSUMÉ

BACKGROUND: The peanut basophil activation test (BAT) has demonstrated excellent diagnostic accuracy with heparinized blood, but its clinical utility is limited by the short stability of samples stored in this anticoagulant. OBJECTIVE: Using EDTA anticoagulated blood, these investigations determined if Peanut BAT sample stability can be extended to 2 days, the minimum stability requirement for diagnostic tests currently offered through American reference laboratories. METHODS: Peanut non-allergic control (NAC), peanut IgE sensitized (PS), and peanut allergic (PA) children aged 6 months through 17 years were recruited from members of Kaiser Permanente Southern California. EDTA anti-coagulated blood samples were collected from participants, shipped to a centralized laboratory, and stored at 4oC for peanut BAT testing 1 and 2 days later. RESULTS: Peanut BAT results for 23 unblinded participants were used to establish sample rejection and interpretation criteria that were subsequently validated in a prospective double-blind study involving 112 additional children (39-NAC, 36-PS, 37-PA). Of 105 blinded blood samples tested on each study day, 88 (84%) day-1 and 90 (86%) day-2 peanut BAT results were considered interpretable, with diagnostic accuracies of 95.5% and 94.4%, respectively. Moreover, all interpretable PA results were considered positive (100% sensitivity). CONCLUSION: Using EDTA anti-coagulated blood samples collected remotely, 1 and 2 days before testing, study results highlight the favorable diagnostic performance characteristics of the peanut BAT and provide further evidence that the test could be readily operationalized for clinical use by interested commercial reference laboratories.

16.
Math Biosci ; : 109247, 2024 Jul 03.
Article de Anglais | MEDLINE | ID: mdl-38969058

RÉSUMÉ

The human papillomavirus (HPV) is threatening human health as it spreads globally in varying degrees. On the other hand, the speed and scope of information transmission continues to increase, as well as the significant increase in the number of HPV-related news reports, it has never been more important to explore the role of media news coverage in the spread and control of the virus. Using a decreasing factor that captures the impact of media on the actions of people, this paper develops a model that characterizes the dynamics of HPV transmission with media impact, vaccination and recovery. We obtain global stability of equilibrium points employing geometric method, and further yield effective methods to contain the HPV pandemic by sensitivity analysis. With the center manifold theory, we show that there is a forward bifurcation when R0=1. Our study suggested that, besides controlling contact between infected and susceptible populations and improving effective vaccine coverage, a better intervention would be to strengthen media coverage. In addition, we demonstrated that contact rate and the effect of media coverage result in multiple epidemics of infection when certain conditions are met, implying that interventions need to be tailored to specific situations.

17.
J Environ Sci (China) ; 146: 67-80, 2024 Dec.
Article de Anglais | MEDLINE | ID: mdl-38969463

RÉSUMÉ

Groundwater is the main source of drinking water for the rural population in the chronic kidney disease of unknown etiology (CKDu) zone of the North Central Province (NCP) in Sri Lanka. In this study, a total of 334 groundwater samples (311 dug wells, 21 tube wells and 2 springs) during the wet season from two aquifers in the NCP were collected, and investigated their chemical characteristics and evaluate their water quality, including groundwater chemistry, main ion sources, the corrosion and scaling potential of groundwater. The results showed that the two hydrochemical types of groundwater in the NCP were mainly of the Ca-HCO3, Na·Ca-HCO3 types, with the main HCO3-, Na+ and Ca2+ ions in both types of groundwater originating from silicate and evaporite salt dissolution and influenced by alternating cation adsorption, while the presence of NO3- was mainly anthropogenic. Evaluation of water stability using namely Langelier saturation index (LSI), Ryznar stability index (RSI), Puckorius scaling index (PSI) and Larson-Skold index (LS), indicated that most groundwater presents corrosion potential and has corrosion behavior tendency of metals to some degrees. The water quality of Polonnaruwa was better than that of Anuradhapura in the NCP, and when the groundwater was worse than the "good" grade, which must be properly treated before it is used as drinking water.


Sujet(s)
Surveillance de l'environnement , Nappe phréatique , Polluants chimiques de l'eau , Sri Lanka , Nappe phréatique/composition chimique , Polluants chimiques de l'eau/analyse , Qualité de l'eau , Insuffisance rénale chronique , Eau de boisson/composition chimique , Eau de boisson/analyse , Alimentation en eau
18.
Stem Cell Res Ther ; 15(1): 191, 2024 Jul 02.
Article de Anglais | MEDLINE | ID: mdl-38956608

RÉSUMÉ

BACKGROUND: Stem cell-derived therapies hold the potential for treatment of regenerative clinical indications. Static culture has a limited ability to scale up thus restricting its use. Suspension culturing can be used to produce target cells in large quantities, but also presents challenges related to stress and aggregation stability. METHODS: Utilizing a design of experiments (DoE) approach in vertical wheel bioreactors, we evaluated media additives that have versatile properties. The additives evaluated are Heparin sodium salt (HS), polyethylene glycol (PEG), poly (vinyl alcohol) (PVA), Pluronic F68 and dextran sulfate (DS). Multiple response variables were chosen to assess cell growth, pluripotency maintenance and aggregate stability in response to the additive inputs, and mathematical models were generated and tuned for maximal predictive power. RESULTS: Expansion of iPSCs using 100 ml vertical wheel bioreactor assay for 4 days on 19 different media combinations resulted in models that can optimize pluripotency, stability, and expansion. The expansion optimization resulted in the combination of PA, PVA and PEG with E8. This mixture resulted in an expansion doubling time that was 40% shorter than that of E8 alone. Pluripotency optimizer highlighted the importance of adding 1% PEG to the E8 medium. Aggregate stability optimization that minimizes aggregate fusion in 3D culture indicated that the interaction of both Heparin and PEG can limit aggregation as well as increase the maintenance capacity and expansion of hiPSCs, suggesting that controlling fusion is a critical parameter for expansion and maintenance. Validation of optimized solution on two cell lines in bioreactors with decreased speed of 40 RPM, showed consistency and prolonged control over aggregates that have high frequency of pluripotency markers of OCT4 and SOX2 (> 90%). A doubling time of around 1-1.4 days was maintained after passaging as clumps in the optimized medium. Controlling aggregate fusion allowed for a decrease in bioreactor speed and therefore shear stress exerted on the cells in a large-scale expansion. CONCLUSION: This study resulted in a control of aggregate size within suspension cultures, while informing about concomitant state control of the iPSC state. Wider application of this approach can address media optimization complexity and bioreactor scale-up challenges.


Sujet(s)
Bioréacteurs , Cellules souches pluripotentes induites , Humains , Cellules souches pluripotentes induites/métabolisme , Cellules souches pluripotentes induites/cytologie , Techniques de culture cellulaire/méthodes , Prolifération cellulaire , Agrégation cellulaire/effets des médicaments et des substances chimiques , Polyéthylène glycols/composition chimique , Polyéthylène glycols/pharmacologie , Différenciation cellulaire
19.
Heliyon ; 10(11): e32228, 2024 Jun 15.
Article de Anglais | MEDLINE | ID: mdl-38961950

RÉSUMÉ

In this research, an innovative protocol is introduced to address crucial deficiencies in the formulation of chitosan nanoparticles (Cs NPs). While NPs show potential in drug delivery systems (DDSs), their application in the clinic is hindered by various drawbacks, such as toxicity, high material costs, and time-consuming and challenging preparation procedures. Within polymer-based NPs, Cs is a plentiful natural substance derived from the deacetylation of chitin, which can be sourced from the shells of shrimp or crab. Cs NPs can be formulated using the ionic gelation technique, which involves the use of a negatively charged agent, such as tripolyphosphate (TPP), as a crosslinking agent. Even though Cs is a cost-effective and biocompatible material, the formulation of Cs NPs with the correct size and surface electrical charge (zeta potential) presents a persistent challenge. In this study, various techniques were employed to analyze the prepared Cs NPs. The size and surface charge of the NPs were evaluated using dynamic light scattering (DLS). Morphological analysis was conducted using field emission-scanning electron microscopy (FE-SEM). The chemical composition and formation of Cs NPs were investigated using Fourier transform infrared (FTIR). The stability analysis was confirmed through X-ray diffraction (XRD) analysis. Lastly, the biocompatibility of the NPs was assessed through cell cytotoxicity evaluation using the MTT assay. Moreover, here, 11 formulations with different parameters such as reaction pH, Cs:TPP ratio, type of Cs/TPP, and ultrasonication procedure were prepared. Formulation 11 was chosen as the optimized formulation based on its high stability of more than three months, biocompatibility, nanosize of 75.6 ± 18.24 nm, and zeta potential of +26.7 mV. To conclude, the method described here is easy and reproducible and can be used for facile preparation of Cs NPs with desirable physicochemical characteristics and engineering ideal platforms for drug delivery purposes.

20.
Front Netw Physiol ; 4: 1399352, 2024.
Article de Anglais | MEDLINE | ID: mdl-38962160

RÉSUMÉ

Physiological networks are usually made of a large number of biological oscillators evolving on a multitude of different timescales. Phase oscillators are particularly useful in the modelling of the synchronization dynamics of such systems. If the coupling is strong enough compared to the heterogeneity of the internal parameters, synchronized states might emerge where phase oscillators start to behave coherently. Here, we focus on the case where synchronized oscillators are divided into a fast and a slow component so that the two subsets evolve on separated timescales. We assess the resilience of the slow component by, first, reducing the dynamics of the fast one using Mori-Zwanzig formalism. Second, we evaluate the variance of the phase deviations when the oscillators in the two components are subject to noise with possibly distinct correlation times. From the general expression for the variance, we consider specific network structures and show how the noise transmission between the fast and slow components is affected. Interestingly, we find that oscillators that are among the most robust when there is only a single timescale, might become the most vulnerable when the system undergoes a timescale separation. We also find that layered networks seem to be insensitive to such timescale separations.

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