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1.
Psychol Health Med ; 29(4): 778-790, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37455376

RESUMO

Although the association between self-regulation of fatigue and health-related quality of life (HRQoL) has been confirmed, the potential mechanism remains unclear. This study aimed to explore the role of health literacy, health behavior, and exercise frequency in the relationship among middle-aged and elderly patients with recurrent stroke. A cross-sectional survey was conducted. A total of 176 patients completed the survey, in which self-regulation of fatigue, HRQoL, health literacy and health behavior were measured by questionnaires. Based on Bootstrap analyses, a moderating sequential mediation model using PROCESS software was constructed with health literacy and health behavior as mediators and exercise frequency as the moderator. Of the participants, the mean age was 65.44 ± 12.43 years. Self-regulation of fatigue was found to affect HRQoL indirectly through two significant mediation pathways: (1) health literacy (ß=-0.11, 95%CI = -0.20, -0.03), which accounted for 28.79% of the total effect, and (2) health literacy and health behavior (ß=-0.02, 95%CI = -0.05, -0.00), which accounted for 4.80% of the total effect. Exercise frequency moderated the relationship between self-regulating fatigue and HRQoL. Specifically, the interaction term between self-regulating fatigue and exercise frequency significantly predicted HRQoL (ß = 0. 25, t = 2.55, p < 0.05). These findings highlight the role of health literacy and health behavior as sequential mediators of the relationship between self-regulating fatigue and HRQoL. Moreover, exercise frequency moderated the relationship between self-regulating fatigue and HRQoL. Encouraging patients with recurrent stroke to increase exercise frequency appropriately might improve HRQoL for patients with poor health literacy and health behavior.


Assuntos
Qualidade de Vida , Acidente Vascular Cerebral , Pessoa de Meia-Idade , Idoso , Humanos , Estudos Transversais , Inquéritos e Questionários , Fadiga/epidemiologia , Acidente Vascular Cerebral/epidemiologia
2.
Int J Hyperthermia ; 40(1): 2211269, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37474116

RESUMO

INTRODUCTION: The temperature control of magnetic hyperthermia therapy mainly relies on circulating water cooling and regulating magnetic field intensity, which increases complexity in clinical applications. Using magnetic materials with appropriate Curie temperature has become an effective means to solve temperature monitoring and potentially achieve self-regulating temperature. METHODS: A self-temperature-regulating Fe83Zr10B7 magnetic material was prepared. Based on this material, a simplified model of magnetic hyperthermia for arm tumors was established and verified using the finite- element method. The influence of magnetic field intensity and frequency on the heating power and temperature rise rate of different-sized and shaped magnetic media was studied. Additionally, factors such as the size, quantity, and spatial arrangement of the magnetic media were analyzed for their impact on the damage to tumors with different volumes and shapes. RESULTS: Spherical shape is the most suitable for magnetic hyperthermia media, and the radius of the spherical magnetic media can be chosen according to the size of the tumor. For tumors with a radius below 10 mm, using magnetic media with a particle size of 3.5 mm is recommended. The optimal magnetic field conditions are H0 (10-12 kA/m) and f (110-120 kHz). CONCLUSION: Based on the good magnetic properties and heating performance of the Fe83Zr10B7 magnetic material, it is feasible to use it as a magnetic medium for magnetic hyperthermia. The results of this study provide references for the selection of thermal seed size and magnetic field parameters in magnetic hyperthermia.


Assuntos
Hipertermia Induzida , Neoplasias , Humanos , Temperatura , Hipertermia Induzida/métodos , Magnetismo , Neoplasias/terapia , Campos Magnéticos
3.
Technol Forecast Soc Change ; 175: 121348, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34789950

RESUMO

Among many influences that the pandemic has and will have on society and the World System as a whole, one of the most important is the acceleration of the start of a new technological wave and a new technological paradigm in the near future. This impact is determined by the growing need for the development of a number of areas in medicine, bio- and nanotechnology, artificial intelligence and others, which we denote as "MANBRIC convergence". It is shown that the experience of dealing with the COVID-19 pandemic has confirmed that the final phase of the Cybernetic Revolution will begin in the 2030s at the intersection of a number of medical, bio, digital and several other technologies, with medical needs as an integrating link. Among the multitude of self-regulating systems in the economy and life (which, in our opinion, will flourish during the Cybernetic Revolution) socio-technical self-regulating systems (SSSs) will play a special role. Thus, COVID-19 becomes a powerful impetus not only in terms of accelerating technological development and approaching the final phase of the Cybernetic Revolution, but also in changing sociopolitical (and socio-administrative) relations in the forthcoming decades.

4.
Int J Hyperthermia ; 38(1): 13-21, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33491511

RESUMO

Aim: Magnetic hydrogels (MHGs) have been proposed to avoid the redistribution and loss of magnetic nanoparticles (MNPs) when administrated by intratumoral injection. However, the requirement of complex cooling systems and temperature monitoring systems still hinder the clinical application of MHGs. This study investigates the feasibility of developing an MHG to realize the self-regulation of hyperthermia temperature. Methods: The MHG was developed by dispersing the MNPs with self-regulating temperature property into the temperature-sensitive hydrogel through physical crosslinking. The MHG's gelation temperature was tested by measuring the storage modulus and loss modulus on a rotational rheometer. The biocompatibility of the MHG and MNPs was characterized by CCK-8 assay against HaCaT cells. The in vivo magnetic heating property was examined through monitoring the temperature in the MHG on mice back upon the application of the alternating magnetic field (400 ± 5 Oe, 100 ± 5 kHz) every week for successive six weeks. Results: The gelation temperature of the MHG falls in 28.4°C-37.4°C. At in vivo applied concentration of 80 mg/mL, the MHG exhibits over 80% cell viability after 72 h, significantly higher than 50% cell viability of the MNPs (p<0.001). The MHG's stable magnetic hyperthermia temperatures in vivo are in the range of 43.4°C-43.8°C. Conclusions: The developed MHG can be injected using a syringe and will solidify upon body temperature. The biocompatibility is improved after the MNPs being made into MHG. The MHG can self-regulate the temperature for six weeks, exhibiting application potential for self-regulating temperature hyperthermia.


Assuntos
Hipertermia Induzida , Nanopartículas de Magnetita , Animais , Hidrogéis , Hipertermia , Campos Magnéticos , Camundongos , Temperatura
5.
J Nanobiotechnology ; 19(1): 335, 2021 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-34689765

RESUMO

Photothermal therapy (PTT), which converts light energy to heat energy, has become a new research hotspot in cancer treatment. Although researchers have investigated various ways to improve the efficiency of tumor heat ablation to treat cancer, PTT may cause severe damage to normal tissue due to the systemic distribution of photothermal agents (PTAs) in the body and inaccurate laser exposure during treatment. To further improve the survival rate of cancer patients and reduce possible side effects on other parts of the body, it is still necessary to explore PTAs with high selectivity and precise treatment. In this review, we summarized strategies to improve the treatment selectivity of PTT, such as increasing the accumulation of PTAs at tumor sites and endowing PTAs with a self-regulating photothermal conversion function. The views and challenges of selective PTT were discussed, especially the prospects and challenges of their clinical applications.


Assuntos
Neoplasias/terapia , Terapia Fototérmica , Animais , Humanos , Camundongos
6.
Angew Chem Int Ed Engl ; 60(38): 21062-21068, 2021 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-34252251

RESUMO

Chemical reaction networks (CRN) embedded in hydrogels can transform responsive materials into complex self-regulating materials that generate feedback to counter the effect of external stimuli. This study presents hydrogels containing the ß-cyclodextrin (CD) and ferrocene (Fc) host-guest pair as supramolecular crosslinks where redox-responsive behavior is driven by the enzyme-fuel couples horse radish peroxidase (HRP)-H2 O2 and glucose oxidase (GOx)-d-glucose. The hydrogel can be tuned from a responsive to a self-regulating supramolecular system by varying the concentration of added reduction fuel d-glucose. The onset of self-regulating behavior is due to formation of oxidation fuel in the hydrogel by a cofactor intermediate GOx[FADH2 ]. UV/Vis spectroscopy, rheology, and kinetic modeling were employed to understand the emergence of out-of-equilibrium behavior and reveal the programmable negative feedback response of the hydrogel, including the adaptation of its elastic modulus and its potential as a glucose sensor.

7.
J Surg Res ; 251: 248-253, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32179277

RESUMO

BACKGROUND: Our group has shown that personalized video feedback (PVF) is better than a task demonstration video at increasing wound closure skills among incoming surgical interns. However, offering PVF can be time-consuming. We sought to compare the educational effects and time required for group video feedback (GVF) and PVF. METHODS: We have mailed our matched incoming "surgical" interns a "welcome package" in mid-March for the past 3 y. The package includes similar resources each year. Incoming interns were asked to video record themselves performing six tasks three separate times between April 1 and June 15. After each submission in 2016 and 2017, incoming interns received 2 min of personalized feedback on their three separate wound closure videos (PVF). In 2018, incoming interns received 5 min of group-based feedback three separate times covering all six tasks (GVF). We compared performance (July Surgical Olympics) of these six skills against the interns from the previous 2 y who received PVF on only one skill (suturing). RESULTS: Twenty-three incoming interns received the pre-residency package and participated in the 2018 Surgical Olympics. This 2018 GVF class had a higher overall mean score for six stations (31.5 [standard deviation = ±7.7]) than the 2016 and 2017 PVF classes (25.6 [standard deviation = ±8]; P < 0.0001). Knot tying ability and suturing skill were similar between the classes. The GVF group performed better on the remaining four skills . The total time of surgical staff and educators spent per class in 2018 (GVF class) was 30 min and includes six tasks compared with 276 min of effort in each of the 2016 and 2017 classes (PVF included one task). CONCLUSIONS: GVF and PVF as a component of preemptive training had the same effect on improving suturing skills among the interns. GVF required less educator editing and voice over time. GVF is effective and efficient in enhancing incoming interns' performance in multiple skills.


Assuntos
Competência Clínica , Feedback Formativo , Internato e Residência/métodos , Gravação em Vídeo , Técnicas de Fechamento de Ferimentos/educação , Currículo , Humanos , Técnicas de Sutura/educação
8.
Acta Neurochir (Wien) ; 159(12): 2351-2354, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28905154

RESUMO

BACKGROUND: A relevant irrigating and flushing maneuver during cerebral microsurgical procedures allows for a neat and optimal operative field. However, when operating on the deep region of the brain, a delicately created slim surgical corridor could unintentionally hinder the assisting surgeon from properly performing this routine maneuver. METHOD: To address this problem, the authors devised a useful and convenient irrigation system that can be used during cerebral microsurgery. RESULTS: This system only necessitates a readily available silastic feeding tube and a malleable wire. The advantages of our devised system include the convenience of free molding, good endurance of the molded contour, and easy control over the amount of irrigation. CONCLUSIONS: In this report, the authors demonstrated technical tips for using this newly devised system.


Assuntos
Catéteres , Microcirurgia/instrumentação , Dimetilpolisiloxanos , Humanos , Microcirurgia/métodos , Sucção/instrumentação , Irrigação Terapêutica/instrumentação
9.
Indian J Crit Care Med ; 21(8): 528-530, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28904484

RESUMO

BACKGROUND: The two most commonly used types of humidifiers are heated humidifiers and heat and moisture exchange humidifiers. Heated humidifiers provide adequate temperature and humidity without affecting the respiratory pattern, but overdose can cause high temperatures and humidity resulting in condensation, which increases the risk of bacteria in the circuit. These devices are expensive. Heat and moisture exchanger filter is a new concept of humidification, increasing the moisture content in inspired gases. AIMS: This study aims to determine the effectiveness of the heat and moisture exchanger (HME)-Booster system to humidify inspired air in patients under mechanical ventilation. MATERIALS AND METHODS: We evaluated the humidification provided by 10 HME-Booster for tracheostomized patients under mechanical ventilation using Servo I respirators, belonging to the Maquet company and Evita 4. RESULTS: There was an increase in the inspired air humidity after 1 h with the humidifier. CONCLUSION: The HME-Booster combines the advantages of heat and moisture exchange minimizing the negatives. It increases the amount of moisture in inspired gas in mechanically ventilated tracheostomized patients. It is easy and safe to use. The type of ventilator used has no influence on the result.

10.
J Theor Biol ; 408: 222-236, 2016 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-27528448

RESUMO

Using an analytically solvable stochastic model, we study the properties of a simple genetic circuit consisting of multiple copies of a self-regulating gene. We analyse how the variation in gene copy number and the mutations changing the auto-regulation strength affect the steady-state distribution of protein concentration. We predict that one-reporter assay, an experimental method where the extrinsic noise level is inferred from the comparison of expression variance of a single and duplicated reporter gene, may give an incorrect estimation of the extrinsic noise contribution when applied to self-regulating genes. We also show that an imperfect duplication of an auto-activated gene, changing the regulation strength of one of the copies, may lead to a hybrid, binary+graded response of these genes to external signal. The analysis of relative changes in mean gene expression before and after duplication suggests that evolutionary accumulation of gene duplications may, at a given mean burst size, non-trivially depend on the inherent noisiness of a given gene, quantified by the inverse of the maximal mean frequency of bursts. Moreover, we find that the dependence of gene expression noise on gene copy number and auto-regulation strength may qualitatively differ, e.g. in monotonicity, depending on whether the noise is measured by Fano factor or coefficient of variation. Thus, experimentally-based hypotheses linking gene expression noise and evolutionary optimisation in the context of gene copy number variation may be ambiguous as they are dependent on the particular function chosen to quantify noise.


Assuntos
Dosagem de Genes/genética , Regulação da Expressão Gênica , Homeostase/genética , Variações do Número de Cópias de DNA , Evolução Molecular , Redes Reguladoras de Genes
11.
Materials (Basel) ; 17(5)2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38473695

RESUMO

Electrical properties and electro-thermal behavior were studied in composites with carbon black (CB) or hybrid filler (CB and graphite) and a matrix of linear low-density polyethylene (LLDPE). LLDPE, a (co)polymer with low crystallinity but with high structural regularity, was less studied for Positive Temperature Coefficient (PTC) applications, but it would be of interest due to its higher flexibility as compared to HDPE. Structural characterization by scanning electron microscopy (SEM) confirmed a segregated structure resulted from preparation by solid state powder mixing followed by hot molding. Direct current (DC) conductivity measurements resulted in a percolation threshold of around 8% (w) for CB/LLDPE composites. Increased filler concentrations resulted in increased alternating current (AC) conductivity, electrical permittivity and loss factor. Resistivity-temperature curves indicate the dependence of the temperature at which the maximum of resistivity is reached (Tmax(R)) on the filler concentration, as well as a differentiation in the Tmax(R) from the crystalline transition temperatures determined by DSC. These results suggest that crystallinity is not the only determining factor of the PTC mechanism in this case. This behavior is different from similar high-crystallinity composites, and suggests a specific interaction between the conductive filler and the polymeric matrix. A strong dependence of the PTC effect on filler concentration and an optimal concentration range between 14 and 19% were also found. Graphite has a beneficial effect not only on conductivity, but also on PTC behavior. Temperature vs. time experiments, revealed good temperature self-regulation properties and current and voltage limitation, and irrespective of the applied voltage and composite type, the equilibrium superficial temperature did not exceed 80 °C, while the equilibrium current traversing the sample dropped from 22 mA at 35 V to 5 mA at 150 V, proving the limitation capacities of these materials. The concentration effects revealed in this work could open new perspectives for the compositional control of both the self-limiting and interrupting properties for various low-temperature applications.

12.
Int J Offender Ther Comp Criminol ; : 306624X241236717, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38500047

RESUMO

The dual systems model is a psychological framework centered on differential development of sensation-seeking and impulse control during adolescence and emerging adulthood with implications for understanding antisocial behavior. However, there is a dearth of research which has examined mental illness as a driver of differential development of these constructs. This study examined major depressive disorder as a risk factor for elevated sensation-seeking and diminished impulse control and tested to determine whether the salience differed by age. The Pathways to Desistance data were analyzed. Mixed effects models examined the direct effect of major depressive disorder on dual systems outcomes and test for moderation by age. Findings indicated that major depressive disorder at baseline was associated with increased sensation-seeking and diminished impulse control. Relationships did not differ in salience based on age. Results suggest that treatment effective for addressing depression may have relevance for mitigating the impact of the disorder on cognition.

13.
ACS Appl Mater Interfaces ; 16(26): 33539-33547, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38914535

RESUMO

The irreversible oxygen-redox reactions in the high-voltage region of sodium-layered cathode materials lead to poor capacity retention and structural instability during cycling, presenting a significant challenge in the development of high-energy-density sodium-ion batteries. This work introduces a high-entropy design for layered Na0.67Li0.1Co0.1Cu0.1Ni0.1Ti0.1Mn0.5O2 (Mn-HEO) cathode with a self-regulating mechanism to extend specific capacity and energy density. The oxygen redox reaction was activated during the initial charging process, accompanied by the self-regulation of active elements, enhancing the ionic bonds to form a vacancy wall near the TM vacancies and thus preventing the migration of transition metal elements. Systematic in situ/ex situ characterizations and theoretical calculations comprehensively support the understanding of the self-regulation mechanism of Mn-HEO. As a result, the Mn-HEO cathode exhibits a stable structure during cycling. It demonstrates almost zero strain within a wide voltage range of 2.0-4.5 V with a remarkable specific capacity (177 mAh g-1 at 0.05 C) and excellent long-term cycling stability (87.6% capacity retention after 200 cycles at 2 C). This work opens a new pathway for enhancing the stability of oxygen-redox chemistry and revealing a mechanism of crystal structure evolution for high-energy-density layered oxides.

14.
Eur J Soc Theory ; 27(1): 78-96, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38343560

RESUMO

Polanyi's (1957 [1944]) The Great Transformation stands as a towering analysis of the industrial revolution and a powerful social warning against social and natural damage driven by the pursuit of maximal economic value. Polanyi envisioned that the 'discovery of society', due to its radical neglect during the industrial revolution, led to this new social knowledge resulting in the end of laissez-faire and the self-regulating market. Yet, the most recent phase of the industrial revolution, the digital phase, suggests that many of the same failures to manage industrial revolutions are occurring again. In particular, looking at the emerging digital economy through the prism of Polanyi's social theory, this article argues that the changes driven by the digital economy, specifically in terms of the reshaping of attention and sociality and the increasing potential for 'normal catastrophes', suggests that Polanyi's lesson of the destructive power of the self-regulating market is again being neglected.

15.
Neural Netw ; 168: 123-142, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37748392

RESUMO

This paper makes a new breakthrough in deliberating the bifurcations of fractional-order bidirectional associative memory neural network (FOBAMNN). In the beginning, the corresponding bifurcation results are established according to self-regulating parameter, which is different from bifurcation outcomes available by using time delay as the bifurcation parameter, and greatly enriches the bifurcation results of continuous neural networks(NNs). The deived results manifest that a larger self-regulating parameter is more conducive to the stability of the system, which is consistent with the actual meaning of the self-regulating parameter representing the decay rate of activity. In addition to the innovation in the research object, this paper also has innovation in the procedure of calculating the bifurcation critical point. In the face of the quartic equation about the bifurcation parameters, this paper utilizes the methodology of implicit array to calculate the bifurcation critical point succinctly and effectively, which eschews the disadvantages of the conventional Ferrari approach, such as cumbersome formula and huge computational efforts. Our developed technique can be employed as a general method to solve the bifurcation point including the problem of dealing with the bifurcation critical point of delay. Ultimately, numerical experiments test the key theoretical fruits of this paper.


Assuntos
Algoritmos , Redes Neurais de Computação , Frutas
16.
Front Psychol ; 14: 1176477, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37519400

RESUMO

Experiencing school burnout symptoms can have negative consequences for learning. A growth mindset, the belief that human qualities such as intelligence are malleable, has previously been correlated with fewer school burnout symptoms in late adolescents. This might be because adolescents with a stronger growth mindset show more adaptive self-regulation strategies and thereby increasing resilience against academic setbacks. Here we confirmed in a sample of 426 Dutch young adolescents (11-14 years old; 48% female) that this relationship between growth mindset and school burnout symptoms holds after controlling for other potential predictors of school burnout symptoms such as academic achievement, school track, gender, and socio-economic status. Our second aim was to increase our understanding of the mechanism underlying the relation between mindset and school burnout, by measuring physiological resilience (vagal activity, a measure of parasympathetic activity, also known as heart rate variability or HRV) in a subsample (n = 50). We did not find any relation between vagal activity and growth mindset or school burnout symptoms, nor could we establish a mediating effect of vagal activity in their relation. In conclusion, we found evidence for a potential protective effect of a growth mindset on school burnout symptoms in young adolescents, but not for physiological resilience (vagal activity) as an underlying mechanism. The protective effect of growth mindset as confirmed in our younger sample can be leveraged in interventions to prevent increasing school burnout symptoms.

17.
Materials (Basel) ; 16(1)2022 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-36614495

RESUMO

A novel conductive composite material with homogeneous binary polymer matrix of HDPE (HD) and LLDPE (LLD), mixed with conductive filler consisting of carbon black (CB) and graphite (Gr), was tested against a HDPE composite with a similar conductive filler. Even the concentration of the conductive filler was deliberately lower for (CB + Gr)/(LLD + HD), and the properties of this composite are comparable or better to those of (CB + Gr)/HD. The kinetic parameters of the ρ-T curves and from the DSC curves indicate that the resistivity peak is obtained when the polymer matrix is fully melted. When subjected to repeated thermal cycles, the composite (CB + Gr)/(LLD + HD) presented a better electrical behavior than composite CB + Gr)/HD, with an increase in resistivity (ρmax) values with the number of cycles, as well as less intense NTC (Negative Temperature Coefficient) effects, both for the crosslinked and thermoplastic samples. Radiation crosslinking led to increased ρmax values, as well as to inhibition of NTC effects in both cases, thus having a clear beneficial effect. Limitation effects of surface temperature and current intensity through the sample were observed at different voltages, enabling the use of these materials as self-regulating heating elements at various temperatures below the melting temperature. The procedure based on physical mixing of the components appears more efficient in imparting lower resistivity in solid state and high PTC (Positive Temperature Coefficient) effects to the composites. This effect is probably due to the concentration of the conductive particles at the surface of the polymer domains, which would facilitate the formation of the conductive paths. Further work is still necessary to optimize both the procedure of composite preparation and the properties of such materials.

18.
Cancers (Basel) ; 14(20)2022 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-36291935

RESUMO

This paper reports a comprehensive investigation of a magnetic nanoparticle (MNP), named M55, which belongs to a class of innovative doped ferrite nanomaterials, characterized by a self-limiting temperature. M55 is obtained from M48, an MNP previously described by our group, by implementing an additional purification step in the synthesis. M55, after citrate and glucose coating, is named G-M55. The present study aimed to demonstrate the properties of G-M55 as a diagnostic contrast agent for MRI and magnetic particle imaging (MPI), and as an antitumoral agent in magnetic fluid hyperthermia (MFH). Similar specific absorption rate values were obtained by standard MFH and by an MPI apparatus. This result is of interest in relation to the application of localized MFH by MPI apparatus. We demonstrated the biocompatibility of G-M55 in a triple-negative human breast cancer line (MDA-MB-231), and its efficacy as an MFH agent in the same cell line. We also demonstrated the efficacy of MFH treatment with G-M55 in an experimental model of breast cancer. Overall, our results pave the way for the clinical application of G-M55 as an MFH agent in breast cancer therapy, allowing not only efficient treatment by both standard MFH apparatus and MPI but also temperature monitoring.

19.
Curr Opin Biotechnol ; 78: 102806, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36194920

RESUMO

Fed-batch culture of Chinese hamster ovary (CHO) cells remains the most commonly used method for producing biopharmaceuticals. Static CHO cell-line engineering approaches have incrementally improved productivity, growth and product quality through permanent knockout of genes with a negative impact on production, or constitutive overexpression of genes with a positive impact. However, during fed-batch culture, conditions (such as nutrient availability) are continually changing. Therefore, traits that are most beneficial during early-phase culture (such as high growth rate) may be less desirable in late phase. Unlike with static approaches, dynamic cell line engineering strategies can optimise such traits by implementing synthetic sense-and-respond programmes. Here, we review emerging synthetic biology tools that can be used to build dynamic, self-regulating CHO cells, capable of detecting intra-/extracellular cues and generating user-defined responses tailored to the stage-specific needs of the production process.


Assuntos
Técnicas de Cultura Celular por Lotes , Biologia Sintética , Cricetinae , Animais , Cricetulus , Células CHO , Técnicas de Cultura Celular por Lotes/métodos , Engenharia Celular , Proteínas Recombinantes/genética
20.
Nanotheranostics ; 5(3): 333-347, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732604

RESUMO

During the last few years, for therapeutic purposes in oncology, considerable attention has been focused on a method called magnetic fluid hyperthermia (MFH) based on local heating of tumor cells. In this paper, an innovative, promising nanomaterial, M48 composed of iron oxide-based phases has been tested. M48 shows self-regulating temperature due to the observable second order magnetic phase transition from ferromagnetic to paramagnetic state. A specific hydrophilic coating based on both citrate ions and glucose molecules allows high biocompatibility of the nanomaterial in biological matrices and its use in vivo. MFH mediator efficiency is demonstrated in vitro and in vivo in breast cancer cells and tumors, confirming excellent features for biomedical application. The temperature increase, up to the Curie temperature, gives rise to a phase transition from ferromagnetic to paramagnetic state, promoting a shortage of the r2 transversal relaxivity that allows a switch in the contrast in Magnetic Resonance Imaging (MRI). Combining this feature with a competitive high transversal (spin-spin) relaxivity, M48 paves the way for a new class of temperature sensitive T2 relaxing contrast agents. Overall, the results obtained in this study prepare for a more affordable and tunable heating mechanism preventing the damages of the surrounding healthy tissues and, at the same time, allowing monitoring of the temperature reached.


Assuntos
Hipertermia Induzida/métodos , Magnetismo , Nanopartículas Metálicas/química , Neoplasias/terapia , Temperatura , Animais , Neoplasias da Mama/terapia , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Difração de Pó , Ensaios Antitumorais Modelo de Xenoenxerto
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