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1.
Article de Anglais | MEDLINE | ID: mdl-38862391

RÉSUMÉ

PURPOSE: The duties of paramedics and emergency medical technicians (P&EMTs) are continuously changing due to developments in medical systems. This study presents evaluation goals for P&EMTs by analyzing their work, especially the tasks that new P&EMTs (with less than 3 years' experience) find difficult, to foster the training of P&EMTs who could adapt to emergency situations after graduation. METHODS: A questionnaire was created based on prior job analyses of P&EMTs. The survey questions were reviewed through focus group interviews, from which 253 task elements were derived. A survey was conducted from July 10, 2023 to October 13, 2023 on the frequency, importance, and difficulty of the 6 occupations in which P&EMTs were employed. RESULTS: The P&EMTs' most common tasks involved obtaining patients' medical histories and measuring vital signs, whereas the most important task was cardiopulmonary resuscitation (CPR). The task elements that the P&EMTs found most difficult were newborn delivery and infant CPR. New paramedics reported that treating patients with fractures, poisoning, and childhood fever was difficult, while new EMTs reported that they had difficulty keeping diaries, managing ambulances, and controlling infection. CONCLUSION: Communication was the most important item for P&EMTs, whereas CPR was the most important skill. It is important for P&EMTs to have knowledge of all tasks; however, they also need to master frequently performed tasks and those that pose difficulties in the field. By deriving goals for evaluating P&EMTs, changes could be made to their education, thereby making it possible to train more capable P&EMTs.


Sujet(s)
Auxiliaires de santé , Compétence clinique , Évaluation des acquis scolaires , Techniciens médicaux des services d'urgence , Humains , Techniciens médicaux des services d'urgence/enseignement et éducation , République de Corée , Enquêtes et questionnaires , Auxiliaires de santé/enseignement et éducation , Évaluation des acquis scolaires/méthodes , Femelle , Mâle , Groupes de discussion , Adulte , Services des urgences médicales , Réanimation cardiopulmonaire/enseignement et éducation , Communication , Paramédicaux
2.
Pharmaceutics ; 16(5)2024 May 20.
Article de Anglais | MEDLINE | ID: mdl-38794351

RÉSUMÉ

Zolpidem is a widely prescribed hypnotic Z-drug used to treat short-term insomnia. However, a growing number of individuals intentionally overdose on these drugs. This study aimed to develop a predictive tool for physicians to assess patients with zolpidem overdose. A population pharmacokinetic (PK) model was established using digitized data obtained from twenty-three healthy volunteers after a single oral administration of zolpidem. Based on the final PK model, a web application was developed using open-source R packages such as rxode2, nonmem2rx, and shiny. The final model was a one-compartment model with first-order absorption and elimination with PK parameters, including clearance (CL, 16.9 L/h), absorption rate constant (Ka, 5.41 h-1), volume of distribution (Vd, 61.7 L), and lag time (ALAG, 0.394 h). Using the established population PK model in the current study, we developed a web application that enables users to simulate plasma zolpidem concentrations and visualize their profiles. This user-friendly web application may provide essential clinical information to physicians, ultimately helping in the management of patients with zolpidem intoxication.

3.
Article de Anglais | MEDLINE | ID: mdl-38684017

RÉSUMÉ

High-Ni layered oxide cathodes are promising candidates for lithium-ion batteries due to their high energy density. However, their cycle stability is compromised by the poor mechanical durability of the particle microstructure. In this study, we investigate the impact of the calcination temperature on microstructural changes, including primary particle growth and pore evolution, using LiNi0.88Mn0.08Co0.04O2 (N884), with an emphasis on the critical calcination temperature for polycrystalline and single-crystal designs in high-Ni cathodes. As the calcination temperature increases, the primary particles undergo a rectangular growth pattern while the pore population decreases. Beyond a certain critical temperature (in this case, 850 °C), a sudden increase in primary particle size and a simultaneous rapid reduction in the pore population are observed. This sudden microstructure evolution leads to poor cycle retention in N884. In contrast, single-crystal particles, free of grain boundaries, synthesized at this critical temperature exhibit superior cycle retention, underscoring the significance of microstructural design over crystalline quality for achieving long-term cyclability. Our study sheds light on the interplay between calcination temperature and microstructural evolution, proposing the critical temperature as a key criterion for single-crystal synthesis.

4.
Sci Rep ; 14(1): 5250, 2024 03 04.
Article de Anglais | MEDLINE | ID: mdl-38438488

RÉSUMÉ

The frequency and intensity of summer extreme climate events are increasing over time, and have a substantial negative effect on plants, which may be evident in their impact on photosynthesis. Here, we examined the photosynthetic responses of Larix kaempferi and Pinus densiflora seedlings to extreme heat (+ 3 °C and + 6 °C), drought, and heavy rainfall by conducting an open-field multifactor experiment. Leaf gas exchange in L. kaempferi showed a decreasing trend under increasing temperature, showing a reduction in the stomatal conductance, transpiration rate, and net photosynthetic rate by 135.2%, 102.3%, and 24.8%, respectively, in the + 6 °C treatment compared to those in the control. In contrast, P. densiflora exhibited a peak function in the stomatal conductance and transpiration rate under + 3 °C treatment. Furthermore, both species exhibited increased total chlorophyll contents under extreme heat conditions. However, extreme precipitation had no marked effect on photosynthetic activities, given the overall favorable water availability for plants. These results indicate that while extreme heat generally reduces photosynthesis by triggering stomatal closure under high vapor pressure deficit, plants employ diverse stomatal strategies in response to increasing temperature, which vary among species. Our findings contribute to the understanding of mechanisms underlying the photosynthetic responses of conifer seedlings to summer extreme climate events.


Sujet(s)
Chaleur extrême , Larix , Pinus , Plant , Photosynthèse
6.
Nat Commun ; 15(1): 1185, 2024 Feb 08.
Article de Anglais | MEDLINE | ID: mdl-38332123

RÉSUMÉ

Recently, the cost of lithium-ion batteries has risen as the price of lithium raw materials has soared and fluctuated. Notably, the highest cost of lithium production comes from the impurity elimination process to satisfy the battery-grade purity of over 99.5%. Consequently, re-evaluating the impact of purity becomes imperative for affordable lithium-ion batteries. In this study, we unveil that a 1% Mg impurity in the lithium precursor proves beneficial for both the lithium production process and the electrochemical performance of resulting cathodes. This is attributed to the increased nucleation seeds and unexpected site-selective doping effects. Moreover, when extended to an industrial scale, low-grade lithium is found to reduce production costs and CO2 emissions by up to 19.4% and 9.0%, respectively. This work offers valuable insights into the genuine sustainability of lithium-ion batteries.

7.
Sci Rep ; 13(1): 22210, 2023 12 14.
Article de Anglais | MEDLINE | ID: mdl-38097646

RÉSUMÉ

Despite the importance of agroforestry parkland systems for ecosystem and livelihood benefits, evidence on determinants of carbon storage in parklands remains scarce. Here, we assessed the direct and indirect influence of human management (selective harvesting of trees), abiotic factors (climate, topography, and soil) and multiple attributes of species diversity (taxonomic, functional, and structural) on aboveground carbon (AGC) stocks in 51 parklands in drylands of Benin. We used linear mixed-effects regressions and structural equation modeling to test the relative effects of these predictors on AGC stocks. We found that structural diversity (tree size diversity, HDBH) had the strongest (effect size ß = 0.59, R2 = 54%) relationship with AGC stocks, followed by community-weighted mean of maximum height (CWMMAXH). Taxonomic diversity had no significant direct relationship with AGC stocks but influenced the latter indirectly through its negative effect on CWMMAXH, reflecting the impact of species selection by farmers. Elevation and soil total organic carbon content positively influenced AGC stocks both directly and indirectly via HDBH. No significant association was found between AGC stocks and tree harvesting factor. Our results suggest the mass ratio, niche complementarity and environmental favorability as underlying mechanisms of AGC storage in the parklands. Our findings also highlight the potential role of human-driven filtering of local species pool in regulating the effect of biodiversity on AGC storage in the parklands. We conclude that the promotion of AGC stocks in parklands is dependent on protecting tree regeneration in addition to enhancing tree size diversity and managing tall-stature trees.


Sujet(s)
Écosystème , Arbres , Humains , Arbres/physiologie , Forêts , Carbone , Biodiversité , Sol , Biomasse
8.
ACS Appl Mater Interfaces ; 15(48): 55837-55847, 2023 Dec 06.
Article de Anglais | MEDLINE | ID: mdl-37983538

RÉSUMÉ

The use of elemental doping in lithium cobalt oxide (LCO) cathode material at high cutoff voltage is a widely adopted technique in the field of rechargeable batteries to mitigate multiple unfavorable phase transitions. However, there is still a lack of fundamental understanding regarding the rationality of each doping element implemented in this method, specifically considering the various thermodynamic stability and phase transitions. Herein, we investigated the effect of Ti doping on an O2 phase LCO (LCTO) cathode material that exhibited enhanced rate performance. We suggest that the incorporation of Ti into an O2 phase LCO results in the mitigation of multiple-phase transitions and the improvement of phase stability, thereby yielding a high-rate-capable cathode material. Through a combination of experimental and computational calculations, we demonstrate that Ti doping improves the thermodynamic stability and kinetics of Li-ions during the cycling process.

9.
Iran J Public Health ; 52(10): 2055-2062, 2023 Oct.
Article de Anglais | MEDLINE | ID: mdl-37899915

RÉSUMÉ

Background: Suicide rate in South Korea is the highest among Organization for Economic Cooperation and Development countries. Particularly it is a major public health concern among adolescents. We investigated the factors affecting suicidal ideation among female Korean adolescents who had experienced sexual intercourse. Methods: This study was a secondary data analysis using the 18th Korea Youth Risk Behavior Survey, conducted using a complex sampling design in 2022. A complex sample multiple logistic regression was performed to analyze data of 1,166 female students who had experienced sexual intercourse. Results: Among the general characteristics, significant differences in suicidal ideation depending on grade, household income, living with family, academic achievement, and allergic dermatitis were observed (P<0.05). Additionally, the factors significantly associated with suicidal ideation were contraceptive use, mental health (generalized anxiety disorder, depressive symptoms, loneliness, and stress), current smoking, drinking, insufficient sleep, and insufficient breakfast consumption (P<0.05). Multiple logistic regression analysis revealed that the factors affecting suicidal ideation were generalized anxiety disorder, perceived stress, loneliness, depressive symptom, and smartphone addiction. Conclusion: For female adolescents with sexual experience, negative mental health and smartphone addiction needed to be managed to reduce suicidal ideation.

10.
Drug Des Devel Ther ; 17: 1107-1114, 2023.
Article de Anglais | MEDLINE | ID: mdl-37077410

RÉSUMÉ

Purpose: The combined administration of bazedoxifene, a tissue-selective estrogen receptor modulator, and cholecalciferol can be a promising therapeutic option for postmenopausal osteoporosis patients. This study aimed to examine the pharmacokinetic interactions between these two drugs and the tolerability of their combined administration in healthy male subjects. Patients and Methods: Thirty male volunteers were randomly assigned to one of the six sequences comprised of three treatments: bazedoxifene 20 mg monotherapy, cholecalciferol 1600 IU monotherapy, and combined bazedoxifene and cholecalciferol therapy. For each treatment, a single dose of the investigational drug(s) was administered orally, and serial blood samples were collected to measure the plasma concentrations of bazedoxifene and cholecalciferol. Pharmacokinetic parameters were calculated using the non-compartmental method. The point estimate and 90% confidence interval (CI) of the geometric mean ratio (GMR) were obtained to compare the exposures of combined therapy and monotherapy. The pharmacokinetic parameters compared were the maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUClast). The safety and tolerability of the combined therapy were assessed in terms of the frequency and severity of adverse events (AEs). Results: For bazedoxifene, the GMR (90% CI) of the combined therapy to monotherapy was 1.044 (0.9263-1.1765) for Cmax and 1.1329 (1.0232-1.2544) for AUClast. For baseline-adjusted cholecalciferol, the GMR (90% CI) of the combined therapy to monotherapy was 0.8543 (0.8005-0.9117) for Cmax and 0.8056 (0.7445-0.8717) for AUClast. The frequency of AEs observed was not significantly different between the combined therapy and monotherapy, and their severity was mild in all cases. Conclusion: A mild degree of pharmacokinetic interaction was observed when bazedoxifene and cholecalciferol were administered concomitantly to healthy male volunteers. This combined therapy was well tolerated at the dose levels used in the present study.


Sujet(s)
Cholécalciférol , Bénévoles , Humains , Mâle , Études croisées , Cholécalciférol/effets indésirables , Équivalence thérapeutique , Volontaires sains , Aire sous la courbe , Administration par voie orale
11.
Glob Chang Biol ; 29(10): 2759-2775, 2023 05.
Article de Anglais | MEDLINE | ID: mdl-36799318

RÉSUMÉ

Large across-model spread in simulating land carbon (C) dynamics has been ubiquitously demonstrated in model intercomparison projects (MIPs), and became a major impediment in advancing climate change prediction. Thus, it is imperative to identify underlying sources of the spread. Here, we used a novel matrix approach to analytically pin down the sources of across-model spread in transient peatland C dynamics in response to a factorial combination of two atmospheric CO2 levels and five temperature levels. We developed a matrix-based MIP by converting the C cycle module of eight land models (i.e., TEM, CENTURY4, DALEC2, TECO, FBDC, CASA, CLM4.5 and ORCHIDEE) into eight matrix models. While the model average of ecosystem C storage was comparable to the measurement, the simulation differed largely among models, mainly due to inter-model difference in baseline C residence time. Models generally overestimated net ecosystem production (NEP), with a large spread that was mainly attributed to inter-model difference in environmental scalar. Based on the sources of spreads identified, we sequentially standardized model parameters to shrink simulated ecosystem C storage and NEP to almost none. Models generally captured the observed negative response of NEP to warming, but differed largely in the magnitude of response, due to differences in baseline C residence time and temperature sensitivity of decomposition. While there was a lack of response of NEP to elevated CO2 (eCO2 ) concentrations in the measurements, simulated NEP responded positively to eCO2 concentrations in most models, due to the positive responses of simulated net primary production. Our study used one case study in Minnesota peatland to demonstrate that the sources of across-model spreads in simulating transient C dynamics can be precisely traced to model structures and parameters, regardless of their complexity, given the protocol that all the matrix models were driven by the same gross primary production and environmental variables.


Sujet(s)
Carbone , Écosystème , Dioxyde de carbone , Changement climatique , Simulation numérique
12.
Death Stud ; 47(2): 221-230, 2023.
Article de Anglais | MEDLINE | ID: mdl-35275034

RÉSUMÉ

The COVID-19 pandemic revealed a need for people and communities for death preparation. Few studies have examined community-level interventions for death preparation and education. This scoping review scrutinized the relevant literature following PRISMA 2018 guidelines. Six databases were searched for articles published between 2010 and 2020. We found that cultural, socioeconomic, and individual values affected death preparation and that online courses and life-death education were effective preparation methods. Additional research is needed to identify the population-specific effectiveness of interventions. To fully investigate death preparation and education at the community level, theory-based studies employing quantitative and qualitative methods are also needed.


Sujet(s)
COVID-19 , Pandémies , Humains
13.
Clin Pharmacol Drug Dev ; 12(1): 21-29, 2023 01.
Article de Anglais | MEDLINE | ID: mdl-36251178

RÉSUMÉ

This study evaluated the pharmacokinetics and pharmacodynamics of the antiplatelet agent prasugrel, and explored its optimal dose regimens via modeling and simulation using NONMEM. We measured platelet aggregation and the serial plasma concentrations of the inactive (R-95913) and active metabolites (R-138727) of prasugrel after a single oral dose of 10-60 mg in 20 healthy adult male volunteers. A pharmacokinetic model for R-95913 and R-138727, and a pharmacodynamic model between the concentration of R-138727 and maximal platelet aggregation measured by light transmittance were constructed. The predictability of the model for platelet aggregation was evaluated by comparing the model prediction values with the observed ones not used in the construction of the model. Pharmacokinetic data were best described by a 3-compartment models for R-95913, a 1-compartment model for R-138727 with transit compartment model for absorption delay, and first-pass metabolic conversion of R-95913 into R-138727 during absorption. The association-dissociation model between R-138727 and its receptor in platelets was applied for the inhibitory effect of prasugrel on platelet aggregation. Prasugrel rapidly inhibited platelet aggregation after oral administration, with a prolonged duration of action; however, the concentration of the active metabolite decreased rapidly, which may have been due to the slow dissociation rate of R-138727 from its target receptor in platelets. The external validation suggests that our model could be used to individualize prasugrel treatment in various clinical situations. Simulation showed rapid onset of inhibitory effect with great magnitude and consistent inhibition after therapeutic dose of prasugrel.


Sujet(s)
Antiagrégants plaquettaires , Agrégation plaquettaire , Adulte , Mâle , Humains , Chlorhydrate de prasugrel/pharmacocinétique , Antiagrégants plaquettaires/pharmacocinétique , Tests fonctionnels plaquettaires , Volontaires sains
14.
Nat Commun ; 13(1): 7638, 2022 Dec 10.
Article de Anglais | MEDLINE | ID: mdl-36496481

RÉSUMÉ

Garnet-type Li7La3Zr2O12 (LLZO) solid electrolytes (SE) demonstrates appealing ionic conductivity properties for all-solid-state lithium metal battery applications. However, LLZO (electro)chemical stability in contact with the lithium metal electrode is not satisfactory for developing practical batteries. To circumvent this issue, we report the preparation of various doped cubic-phase LLZO SEs without vacancy formation (i.e., Li = 7.0 such as Li7La3Zr0.5Hf0.5Sc0.5Nb0.5O12 and Li7La3Zr0.4Hf0.4Sn0.4Sc0.4Ta0.4O12). The entropy-driven synthetic approach allows access to hidden chemical space in cubic-phase garnet and enables lower solid-state synthesis temperature as the cubic-phase nucleation decreases from 750 to 400 °C. We demonstrate that the SEs with Li = 7.0 show better reduction stability against lithium metal compared to SE with low lithium contents and identical atomic species (i.e., Li = 6.6 such as Li6.6La3Zr0.4Hf0.4Sn0.4Sc0.2Ta0.6O12). Moreover, when a Li7La3Zr0.4Hf0.4Sn0.4Sc0.4Ta0.4O12 pellet is tested at 60 °C in coin cell configuration with a Li metal negative electrode, a LiNi1/3Co1/3Mn1/3O2-based positive electrode and an ionic liquid-based electrolyte at the cathode|SE interface, discharge capacity retention of about 92% is delivered after 700 cycles at 0.8 mA/cm2 and 60 °C.


Sujet(s)
Alimentations électriques , Lithium , Électrolytes , Électrodes , Conductivité électrique
15.
Nanotechnology ; 33(48)2022 Sep 09.
Article de Anglais | MEDLINE | ID: mdl-36001950

RÉSUMÉ

The physical role of magnetically semi-hard Co2+cation addition in enhancing the AC heat induction temperature (TAC) or specific loss power (SLP) of solid (CoxMn1-x)Fe2O4superparamagnetic iron oxide nanoparticles (SPIONPs) was systematically investigated at the biologically safe and physiologically tolerable range ofHAC(HAC,safe= 1.12 × 109A m-1s-1,fappl= 100 kHz,Happl= 140 Oe (11.2 A m-1)) to demonstrate which physical parameter would be the most critical and dominant in enhancing theTAC(SLP) of SPIONPs. According to the experimentally and theoretically analyzed results, it was clearly demonstrated that the enhancement of magnetic anisotropy (Ku)-dependent AC magnetic softness including the Néel relaxation time constantτN(≈τeff, effective relaxation time constant), and its dependent out-of-phase magnetic susceptibilityχ″primarily caused by the Co2+cation addition is the most dominant parameter to enhance theTAC(SLP). This clarified result strongly suggests that the development of new design and synthesis methods enabling to significantly enhance theKuby improving the crystalline anisotropy, shape anisotropy, stress (magnetoelastic) anisotropy, thermally-induced anisotropy, and exchange anisotropy is the most critical to enhance theTAC(SLP) of SPIONPs at theHAC,safe(particularly at the lowerfappl< 120 kHz) for clinically safe magnetic nanoparticle hyperthermia.

16.
Nat Chem ; 14(6): 614-622, 2022 Jun.
Article de Anglais | MEDLINE | ID: mdl-35449218

RÉSUMÉ

Nickel-rich layered oxides are envisaged as key near-future cathode materials for high-energy lithium-ion batteries. However, their practical application has been hindered by their inferior cycle stability, which originates from chemo-mechanical failures. Here we probe the solid-state synthesis of LiNi0.6Co0.2Mn0.2O2 in real time to better understand the structural and/or morphological changes during phase evolution. Multi-length-scale observations-using aberration-corrected transmission electron microscopy, in situ heating transmission electron microscopy and in situ X-ray diffraction-reveal that the overall synthesis is governed by the kinetic competition between the intrinsic thermal decomposition of the precursor at the core and the topotactic lithiation near the interface, which results in spatially heterogeneous intermediates. The thermal decomposition leads to the formation of intergranular voids and intragranular nanopores that are detrimental to cycling stability. Furthermore, we demonstrate that promoting topotactic lithiation during synthesis can mitigate the generation of defective structures and effectively suppress the chemo-mechanical failures.

17.
Nat Commun ; 13(1): 1883, 2022 Apr 06.
Article de Anglais | MEDLINE | ID: mdl-35388012

RÉSUMÉ

Lithium metal batteries using solid electrolytes are considered to be the next-generation lithium batteries due to their enhanced energy density and safety. However, interfacial instabilities between Li-metal and solid electrolytes limit their implementation in practical batteries. Herein, Li-metal batteries using tailored garnet-type Li7-xLa3-aZr2-bO12 (LLZO) solid electrolytes is reported, which shows remarkable stability and energy density, meeting the lifespan requirements of commercial applications. We demonstrate that the compatibility between LLZO and lithium metal is crucial for long-term stability, which is accomplished by bulk dopant regulating and dopant-specific interfacial treatment using protonation/etching. An all-solid-state with 5 mAh cm-2 cathode delivers a cumulative capacity of over 4000 mAh cm-2 at 3 mA cm-2, which to the best of our knowledge, is the highest cycling parameter reported for Li-metal batteries with LLZOs. These findings are expected to promote the development of solid-state Li-metal batteries by highlighting the efficacy of the coupled bulk and interface doping of solid electrolytes.

18.
Drug Des Devel Ther ; 16: 425-433, 2022.
Article de Anglais | MEDLINE | ID: mdl-35221673

RÉSUMÉ

PURPOSE: The combined administration of tadalafil, a phosphodiesterase-5 inhibitor, and amlodipine, a calcium channel blocker, can be a promising therapeutic option for hypertension patients with erectile dysfunction. This study aimed to examine the pharmacokinetic drug interaction between tadalafil and amlodipine and the tolerability of their combined administration in healthy male subjects. SUBJECTS AND METHODS: Healthy volunteers (N = 24) were randomly assigned to one of the six sequences that consisted of three treatments: tadalafil (5 mg) alone, amlodipine (10 mg) alone, and tadalafil plus amlodipine. The study drugs were administered orally for 9 d, and the collected serial blood samples were analyzed up to 72 h after the last dosing. Pharmacokinetic parameters were calculated using non-compartmental analysis. RESULTS: For tadalafil, geometric mean ratios (GMRs) (90% confidence interval (CI)) of the combined therapy over the monotherapy were 1.57 (1.46-1.68) for AUCτ,ss and 1.34 (1.24-1.45) for Cmax,ss. For amlodipine, the GMRs (90% CI) of AUCτ,ss and Cmax,ss were 0.93 (0.90-0.97) and 0.95 (0.91-0.99), respectively. The severity of all observed adverse events (AEs) related to the study drugs was mild, and the frequency of AEs of the combined administration was not significantly different from the monotherapy. CONCLUSION: A substantial pharmacokinetic drug interaction between tadalafil and amlodipine was observed with respect to the concentration of tadalafil when administered concomitantly. However, the dose range of the combined administration of tadalafil and amlodipine in the present study was well tolerated by the subjects.


Sujet(s)
Amlodipine , Administration par voie orale , Aire sous la courbe , Études croisées , Interactions médicamenteuses , Volontaires sains , Humains , Mâle , Tadalafil
19.
Nanotechnology ; 33(13)2022 Jan 05.
Article de Anglais | MEDLINE | ID: mdl-34911046

RÉSUMÉ

Magnetic resonance imaging (MRI)-guided magnetic nanofluid hyperthermia (MNFH) is highly desirable in cancer treatment because it can allow for diagnosis, therapeutics, and prognosis simultaneously. However, the application of currently developed iron-oxide based superparamagnetic nanoparticles (IOSPNPs) for an MRI-guided MNFH agent is technically limited by the low AC heat induction power at the physiologically tolerable range of AC magnetic field (HAC,safe), and the low transverser2-relaxivity responsible for the insufficient heating of cancers, and the low resolution of contrast imaging, respectively. Here, pseudo single domain colloidal NixZn1-x-γFe2O3(x = 0.6) superparamagnetic nanoparticle (NiZn-γFe2O3PSD-SPNP) physically and theoretically designed at theHAC,safe, specifically by the applied frequency, is proposed for a highly enhanced MRI-guided MNFH agent application. The NiZn-γFe2O3PSD-SPNP showed the superparamagnetic characteristics, significantly enhanced AC heat induction performance (ILP = 6.3 nHm2kg-1), highly improved saturation magnetization (Ms= 97 emu g-1Fe, 3.55 × 105A m-1) andr2-relaxivity (r2 = 396 mM-1s-1) that are desirable for highly efficient MRI-guided MNFH agent applications. According to the analyzed results, the remarkably enhanced effective relaxation time constant and its dependent out-of-phase magnetic susceptibility, as well as the DC/AC magnetic softness optimized by the PSD-SPNP at theHAC,safewere revealed as the main physical reason for the significance. All the fundamentalin vitroandin vivoexperimental results demonstrated that the physically designed NiZn-γFe2O3PSD-SPNP is bio-technically feasible for a highly efficient MRI-guided MNFH agent for future cancer nanomedicine.


Sujet(s)
Hyperthermie provoquée/méthodes , Imagerie par résonance magnétique/méthodes , Nanoparticules métalliques/composition chimique , Lignée cellulaire tumorale , Colloïdes/composition chimique , Composés du fer III/composition chimique , Humains , Nickel/composition chimique , Composés du zinc/composition chimique
20.
Nanoscale ; 13(46): 19484-19492, 2021 Dec 02.
Article de Anglais | MEDLINE | ID: mdl-34792055

RÉSUMÉ

Magnetic nanofluid hyperthermia (MNFH) with pure superparamagnetic nanoparticles (P-SPNPs) has drawn a huge attraction for cancer treatment modality. However, the low intrinsic loss power (ILP) and attributable degraded-biocompatibility resulting from the use of a heavy dose of P-SPNP agents as well as low heat induction efficiency in biologically safe AC magnetic field (HAC,safe) are challenging for clinical applications. Here, we report an innovatively designed pseudo-single domain-SPNP (PSD-SPNP), which has the same translational advantages as that of conventional P-SPNPs but generates significantly enhanced ILP at HAC,safe. According to the analyzed results, the optimized effective relaxation time, τeff, and magnetic out-of-phase susceptibility, χ'', precisely determined by the particle size at the specific frequency of HAC,safe are the main reasons for the significantly enhanced ILP. Additionally, in vivo MNFH studies with colloidal PSD-SPNPs strongly demonstrated that it can be a promising agent for clinically safe MNFH application with high efficacy.


Sujet(s)
Hyperthermie provoquée , Nanoparticules de magnétite , Nanoparticules , Champs magnétiques , Nanoparticules magnétiques d'oxyde de fer , Magnétisme
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