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This study investigates the microwave ignition behavior of a range of thermites of aluminum, boron, titanium, and tantalum fuels with oxides of Bi2O3, CuO, and Fe2O3. In order to gain insight into the modes of energy transfer leading to ignition, thermites are heated in either a purely electric or magnetic field environment within a single‐mode 2.45 GHz resonant cavity with electric field strengths of 40 to 110 kV/m and magnetic field strengths of 22 to 258 A/m. Thermite stoichiometry is varied as well as particle size and thermite mass. The shortest ignition delays in electric and magnetic fields were found to be 1.37 s (nAl and CuO) and 0.87 s (nAl and CuO), respectively. The use of a variety of carbon susceptors to shorten ignition delay is also studied. Carbon susceptors are found to appreciably shorten ignition delays to as short as 140 and 170 ms for the E and B field respectively (nAl and CuO with multiwalled carbon nanotubes). The results of this work are informative on thermite component choice and the preferred mechanism (electric vs magnetic field) of heating for various thermite compositions for consideration of the increasingly popular ignition via electromagnetic fields. [ABSTRACT FROM AUTHOR]

Cancer treatment remains a pressing global challenge, with magnetic hyperthermia emerging as a promising alternative approach. The article explores the potential of pure and doped magnetite nanoparticles for hyperthermia-based cancer treatment, aiming to enhance therapeutic efficacy while minimizing side effects. Key findings include the synthesis and characterization of NPs—Fe3O4, SnFe2O4, and CoFe2O4—using co-precipitation methods, with emphasis on their size, morphology, magnetic, structural and thermal properties confirmed through techniques like SEM, EDX, VSM, XRD and TGA. The nanoparticles' hyperthermic effects were assessed through infrared imaging, showing CoFe2O4 NPs induced the highest heating efficiency as compared to Fe3O4 and SnFe2O4 NPs. Importantly, all nanoparticles showed negligible hemolysis at a concentration of 0.2 mg/ml, indicating their compatibility with human blood. This study contributes valuable insights into optimizing MNP-based hyperthermia treatments, aiming for safer and more effective cancer therapies in the future. SnFe2O4 NPs haven't been extensively explored in the context of hyperthermia applications, making it a unique contribution to the field. The research employs an innovative and cost-effective method for evaluating the hyperthermic effect of nanoparticles using an infrared camera. This approach overcomes the potential limitations associated with probe-based temperature measurement, offering a more accurate assessment of nanoparticle-induced hyperthermia. The research thoroughly compares its findings with existing literature, highlighting the novelty of the achieved results in terms of maximum hyperthermia with minimal frequency and magnetic field strength without inducing toxicity in human blood. [ABSTRACT FROM AUTHOR]

Direct air capture (DAC) is a promising technology for decarbonization through the removal of CO2 from the atmosphere. In many DAC processes, the regeneration energy used to restore the capture capacity of sorbents accounts for a significant fraction of the energy required by the whole process. Here we report an effective and scalable sorbent regeneration method for liquid DAC solvents based on magnetic nanoparticles (MNPs) heating with AC magnetic fields. MNPs can be directly heated to provide uniform and rapid volumetric heating, as we demonstrate by promoting the release of captured CO2 from an aqueous solution of potassium sarcosinate. Our results showed that 90% of the solvent can be regenerated within 7.5 min of heating through proposed technique. The MNPs and solvent are found to be stable during the regeneration process and the MNPs showed long‐term stability in the CO2‐saturated solvent. Cyclic experiments showed that the nanoparticles can be reused for multiple cycles without performance deterioration. The process is operated in a noncontact mode through electromagnetic waves, making it an adoptable approach for existing carbon capture systems. The MNPs heating provides an effective regeneration strategy for liquid solvents used in carbon capture processes, in particular for DAC. [ABSTRACT FROM AUTHOR]

Magnetic Field Hyperthermia is a technique where tumours are treated through an increase in local temperature upon exposure to alternating magnetic fields (AMFs) that are mediated by magnetic nano-particles (MNPs). In an AMF, these particles heat-up and kill the cells. The relationship between an AMF and the heating-rate is complex, leading to confusion when comparing data for different MNP and AMF conditions. This work allows for the thermal-response to be monitored at multiple AMF amplitudes while keeping other parameters constant. An induction-heating coil was designed based on a Zero-Voltage-Zero-Current (ZVZC) resonant circuit. The coil operates at 93 kHz with a variable DC drive-voltage (12–30 V). NEC4 software was used to model the magnetic field distribution, and MNPs were synthesised by the coprecipitation method. The magnetic field was found to be uniform at the centre of the coil and ranged from 1 kAm−1 to 12 kAm−1, depending on the DC drive-voltage. The MNPs were found to have a specific absorption rate (SAR) of 1.37 Wg−1[Fe] and 6.13 Wg−1[Fe] at 93 kHz and 2.1 kAm−1 and 12.6 kAm−1, respectively. The measured SAR value was found to be directly proportional to the product of the frequency and field-strength (SARα f Ho). This leads to the recommendation that, when comparing data from various groups, the SAR value should be normalized following this relationship and not using the more common relationship based on the square of the field intensity (SARα f Ho2). [ABSTRACT FROM AUTHOR]

The improper treatment of crude oil will cause great harm to the ecological environment and biological health. Traditional oil spill clean-up methods have problems such as high cost and secondary pollution. Thermal-assisted oil absorption material can achieve rapid adsorption of high-viscosity crude oil. The design strategies of thermally assisted oil absorption materials were summarized, including improving hydrophobicity/lipophilicity, enhancing capillary force and increasing thermal effect (Joule heating, photothermal conversion, magnetic heating). The oil absorption mechanism was elaborated from three aspects, namely, heat conversion, heat transfer and oil spill adsorption mechanism. The materials are mainly commercialized sponges and aerogels as carriers to recover crude oil through distillation, extrusion, pumping, etc. Among the four types of thermally assisted oil absorption materials: Joule-heating type needs rapidly raise the temperature at a small voltage to improve safety; there are obvious limitations in solar-type, such as slow warming rate, limited heating uniformity, and highly susceptible to the influence of meteorological conditions; magnetic-heating type is less studied and has challenges in practical application; the combination of solar-assisted and Joule-heating-assisted is common in the composite type. The thermal responsiveness, reusability and recyclability of thermally assisted oil absorption materials need to improve in the future. [ABSTRACT FROM AUTHOR]

The use of global magnetic fields—typically produced by pairs of Maxwell and Helmholtz coils—offers the advantage of generating uniform magnetic fields and magnitude uniform gradient distributions over extensive volumes, while ensuring easy control. However, achieving selective control of multiple magnetic microrobots under such global fields remains problematic. In this study, we utilize a magnetic focus field generated by a pair of Maxwell coils to impede the magnetic torque-based movement of magnetic robots confined within channels. Although the magnetic field is null at the focus field’s center, it increases linearly in all directions. This exerts magnetic forces that push robots, which are situated away from the center, toward the channel walls. This not only restricts their positioning but also reduces their responsiveness to additional fields. By introducing uniform dc magnetic fields to the focus field, we can change the controlled robot. This mechanism for selective locomotion has been empirically validated with the selective movement of two helical magnetic robots and swarms of magnetic microparticles. Furthermore, leveraging the same focus field, we present a novel separation mechanism for magnetic particle swarms, enhancing the aforementioned selective locomotion mechanism. The practical implications of our proposed locomotion mechanism have been showcased in targeted delivery, drilling, and improved magnetic heating experiments.

Using magnetic nanoparticles for extracorporeal magnetic heating applications in bio-medical technology allows higher external field amplitudes and thereby the utilization of particles with higher coercivities (HC). In this study, we report the synthesis and characterization of high coercivity cobalt ferrite nanoparticles following a wet co-precipitation method. Particles are characterized with magnetometry, X-ray diffraction, Mössbauer spectroscopy, transmission electron microscopy (TEM) and calorimetric measurements for the determination of their specific absorption rate (SAR). In the first series, CoxFe3−xO4 particles were synthesized with x = 1 and a structured variation of synthesis conditions, including those of the used atmosphere (O2 or N2). In the second series, particles with x = 0 to 1 were synthesized to study the influence of the cobalt fraction on the resulting magnetic and structural properties. Crystallite sizes of the resulting particles ranged between 10 and 18 nm, while maximum coercivities at room temperatures of 60 kA/m for synthesis with O2 and 37 kA/m for N2 were reached. Magnetization values at room temperature and 2 T (MRT,2T) up to 60 Am2/kg under N2 for x = 1 can be achieved. Synthesis parameters that lead to the formation of an additional phase when they exceed specific thresholds have been identified. Based on XRD findings, the direct correlation between high-field magnetization, the fraction of this antiferromagnetic byphase and the estimated transition temperature of this byphase, extracted from the Mössbauer spectroscopy series, we were able to attribute this contribution to akageneite. When varying the cobalt fraction x, a non-monotonous correlation of HC and x was found, with a linear increase of HC up to x = 0.8 and a decrease for x > 0.8, while magnetometry and in-field Mössbauer experiments demonstrated a moderate degree of spin canting for all x, yielding high magnetization. SAR values up to 480 W/g (@290 kHz, 69 mT) were measured for immobilized particles with x = 0.3, whit the external field amplitude being the limiting factor due to the high coercivities of our particles. [ABSTRACT FROM AUTHOR]

The objective of this work is to study the changes in the physical and mechanical properties of strontium-doped lanthanum manganite (LSM) material and LSM-YSZ (ZrO 2 doped with 8 mol% yttria) composite, obtained by colloidal processing and sintered by 2.45 GHz microwave sintering at 1200 and 1300 °C using two different single-mode cavities. One circular cavity with TE 111 mode that has maximum in the electric field (E -field) and one rectangular cavity with TE 102 mode that has maximum in the magnetic field (H -field). As compared to conventional sintering at 1300 and 1400 °C, the microwave-heated samples exhibited a denser structure for shorter sintering times. LSM-based materials showed higher heating behavior in H -field, which translates into higher energy absorption. This fact can be attributed to an electromagnetic pressure induced by the combined effect of current loops subjected to H -field. Therefore, the interaction between the material and the electromagnetic waves depends on the dominant field of them. [ABSTRACT FROM AUTHOR]

Stable aqueous suspension of magnetic nanoparticles is essential for effective magnetic hyperthermia and other applications of magnetic heating in an alternating magnetic field. However, the alternating magnetic field causes strong agglomeration of magnetic nanoparticles, and this can lead to undesirable phenomena that deteriorate the bulk magnetic properties of the material. It has been shown how this magnetic field influences the distribution of magnetic agglomerates in the suspension. When investigating the influence of the sonication treatment on magnetic colloids, it turned out that the hydrodynamic diameter as a function of sonication time appeared to have a power-law character. The effect of magnetic colloid ageing on magnetic heating was discussed as well. It was shown how properly applied ultrasonic treatment could significantly improve the stability of the colloid of magnetic nanoparticles, ultimately leading to an increase in heating efficiency. The optimal sonication time for the preparation of the magnetic suspension turned out to be time-limited, and increasing it did not improve the stability of the colloid. The obtained results are important for the development of new materials where magnetic colloids are used and in biomedical applications. [ABSTRACT FROM AUTHOR]

Magnetic nanocomposites with a high surface area matrix are attractive materials for novel catalyst supports. They can be remotely and selectively heated inside the reactor vessel when exposed to a high-frequency alternating magnetic field (AMF). These so-called "magnetic" or "cold" catalysts can revolutionize the chemical industry's electrification, particularly for renewable energy applications such as hydrogen storage and release. In this study, we developed a scalable method for synthesizing magnetic Co x Ni 1-x -Al 2 O 3 nanocomposites. The synthesis is based on the co-precipitation of Co and Ni ions from an aqueous solution, coating the precipitated nanoparticles with a boehmite (AlOOH) shell via the in-situ hydrolysis of AlN powder and reduction at 850 °C in a flow of H 2. A combination of X-ray diffractometry (XRD) and scanning transmission electron microscopy (STEM/EDXS) showed the formation of nanocomposites containing globular Co x Ni 1-x nanoparticles (∼ 14 nm in size), homogenously distributed within the matrix composed of thin γ-Al 2 O 3 nanosheets (∼ 30 nm wide and up to 3 nm thick), providing a high specific surface area (∼ 140 m2 g−1). The reduction process was studied using high-temperature XRD, hydrogen-temperature programmed reduction (H 2 -TPR), and X-ray photoelectron spectroscopy (XPS). The magnetic properties were measured with a vibrating-sample magnetometer (VSM). The nanocomposites exhibited an excellent heating ability, exceeding 800 °C within a few minutes, even at relatively low AMF amplitudes (up to 58 mT) in a fixed-bed reactor. These results underscore the potential of Co x Ni 1-x -Al 2 O 3 nanocomposites for high-temperature catalytic processes, marking an advancement in magnetic catalyst support synthesis. [Display omitted] • Scalable synthesis of Co x Ni 1-x -Al 2 O 3 magnetic nanocomposites was developed. • Homogeneous dispersion of Co x Ni 1-x alloyed nanoparticles (∼15 nm) in γ-Al 2 O 3 nanosheets. • Nanocomposites exhibit a high surface area (140 m2 g−1) and soft magnetic properties. • Rapid heating to above 800 °C under low alternating magnetic field amplitudes. • Promising material for high-temperature catalytic processes. [ABSTRACT FROM AUTHOR]

The magnetic heating effect under alternating magnetic fields (AMFs) has recently gained attention in catalysis due to its potential to greatly boost catalytic activities by providing localized heating around magnetic nanoparticles. However, nanoparticles still suffer from low magnetic heating efficiency due to their low magnetic anisotropy and thermal fluctuation, which is a key barrier in the wide application of AMF-assisted catalysis. Herein, by introducing the pinning effect of ferromagnetic/antiferromagnetic (FM/AFM) coupling, NiO/NiOOH (AFM/FM) core-shell nanoparticles exhibit significantly enhanced oxygen evolution reaction activity and resistance to thermal fluctuations under AMF, compared to NiOOH nanoparticles. Notably, magnetized NiO/NiOOH nanoparticles provide an overpotential of 186 mV at 10 mA cm -2 , outperforming unmagnetized ones (218 mV) under the same conditions, further emphasizing the prominent role of the pinning effect in enhanced magnetic heating efficiency. This work provides valuable inspiration to design advanced magnetic catalysts and meet the challenge of the development of AMF-assisted catalysis.

A self-contained nanocapsule for nonspecific cytotoxic anticancer drug delivery and release activated by an enzyme and an alternating magnetic field (AMF) is introduced. This specific prodrug-like drug delivery platform is based on an esterase, an oligomer-based separating barrier, and an ester-linked anticancer peptide melittin encapsulated together in the enlarged pore spaces of the mesoporous silica nanoparticles. A superparamagnetic iron oxide nanoparticle core embedded in the center acts as a nanoheater to stimulate a cascade drug release. Each pore space was designed as a reaction nanovial for the activation of the drug release when the solution inside the nanovial is heated. By employing a thermoresponsive separating barrier as a shield of the peptide drug as well as a separator between the ester-containing peptides and the esterase, the nonspecific cytotoxic effect of the drug and off-target drug release are avoided because the drugs remain inactive in the absence of AMF stimulation. When AMF heating actuates the removal of the separating barrier and exposes the peptide drugs to the enzymes, drug release can be activated. In vivo antitumor experiments further revealed that the nanocapsules exhibited excellent biocompatibility and high tumor-targeting/inhibiting efficiency. The selected esterase, which is in close proximity to the ester-containing peptide drug, efficiently cleaves the ester bonds, thereby causing a catalytic release of peptide drugs and intensified anticancer efficacy. [ABSTRACT FROM AUTHOR]

Oil spills pose significant global environmental and resource wastage issues due to the slow flow of high-viscosity crude oil. Current cleanup methods, such as chemical dispersion, in situ burning, microbial degradation, and mechanical oil skimmers, have limitations such as low recovery rates, secondary pollution, and time consumption. To address these challenges, we developed an eco-friendly magneto-photothermal sponge combining magnetic and photothermal heating. This innovation enables safe, efficient, and continuous cleanup without direct contact. The magneto-photothermal sponge, fabricated through a simple dip-coating and template method, consists of nontoxic polydimethylsiloxane (PDMS) sponge with a biocompatible SiO 2 /Fe 3 O 4 /polydopamine layer. It exhibited rapid adsorption, high capacity (131–344 % for various oils), sustained superhydrophobicity, and reusability. Owing to its magnetothermal and photothermal properties, it was rapidly heated to 178 °C in 3 min under an alternating magnetic field and to 63.5 °C in 5 min under solar irradiation. The sponge efficiently absorbed viscous crude oils, with a recovery rate of 93.33 g h−1 cm−2, which surpasses that reported in previous studies. Combining solar and magnetic heating enhanced recovery, being 13 and 1.2 times more effective than individual solar and magnetic heating, respectively. This low-cost, high flame retardant, durable, dual-heating approach offers an efficient, safe, and eco-friendly solution for cleaning viscous heavy oil spills. [Display omitted] • An eco-friendly stimuli-responsive sponge with a magneto-photothermal effect was reported. • All the feedstock is biocompatible and employs a facile template method and dip-coating process. • The sponge quickly and safely absorbs different oils under magnetic fields, sunlight, or both. • The sponge exhibited a fast and continuous recovery rate of viscous crude oils to 93.33 g h−1 cm−2. [ABSTRACT FROM AUTHOR]

Magnetic heating by nanoparticles has recently been successfully employed in heterogeneous catalysis. In such processes, the maximum temperature that can be reached depends on the Curie temperature (Tc) of the heating material. Here, in order to extend the range of accessible temperatures and consequently the range of possible reactions, to those requiring high temperatures, we developed and fully characterized a series of FeCo nanoparticles containing different concentrations of cobalt, in order to tune their magnetic properties and Tc. Their efficiency is compared to that of iron carbide nanoparticles, which display a lower Tc. Specific absorption rate (SAR) measurements as a function of temperature, performed using a homemade pyrometer-based setup, clearly show that although the heating power of iron carbide nanoparticles is higher at room temperature it decreases more rapidly with temperature than that of iron cobalt nanoparticles, in agreement with their lower Tc. In a showcase, Fe0.5Co0.5 nanoparticles allow, in addition to CO2 hydrogenation, dry reforming of propane and methane, and dehydrogenation of propane, these reactions requiring temperatures of 350 °C, 600 °C, and 700 °C, respectively. Furthermore, the use of Fe0.5Co0.5 nanoparticles is less energy demanding, as it allows carrying out CO2 hydrogenation at lower magnetic fields and at frequencies as low as 100 kHz. Dry reforming of methane and propane were carried out in the presence of a Ni nanoparticle-based catalyst, whereas dehydrogenation of propane required as a catalyst PtSn nanoparticles synthesized through an organometallic route. Fe0.5Co0.5 nanoparticles can therefore be used as universal heating agents allowing reactions to be performed up to ca. 700 °C upon association with the appropriate catalyst. [ABSTRACT FROM AUTHOR]

Purpose: Technologies with low environmental impacts and promoting renewable energy sources are required to meet the energetic demand while facing the increase of gas emissions associated to the greenhouse effect and the depletion of fossil fuels. CO2 methanation activated by magnetic heating has recently been reported as a highly efficient and innovative power-to-gas technology in a perspective of successful renewable energy storage and carbon dioxide valorisation. In this work, the life cycle assessment (LCA) of this process is performed, in order to highlight the environmental potential of the technology, and its competitivity with in respect to conventional heating technologies. Methods: The IMPACT 2002+ was used for this LCA. The process studied integrates methanation, water electrolysis and CO2 capture and separation. This "cradle-to-gate" LCA study does not consider the use of methane, which is the reaction product. The functional unit used is the energy content of the produced CH4. The LCA was carried out using the energy mix data for the years 2020 and 2050 as given by the French Agency for Environment and Energy management (ADEME). Consumption data were either collected from literature or obtained from the LPCNO measurements as discussed by Marbaix (2019). The environmental impact of the CO2 methanation activated by magnetic heating was compared with the environmental impact of a power-to-gas plant using conventional heating (Helmeth) and considering the environmental impact of the natural gas extraction. Results: It is shown that the total flow rate of reactants, the source of CO2 and the energy mix play a major role on the environmental impact of sustainable CH4 production, whereas the lifetime of the considered catalyst has no significant influence. As a result of the possible improvements on the above-mentioned parameters, the whole process is expected to reduce by 75% in its environmental impact toward 2050. This illustrates the high environmental potential of the methanation activated by magnetic heating when coupled with industrial exhausts and renewable electricity production. Conclusions: The technology is expected to be environmentally competitive compared with existing similar processes using external heating sources with the additional interest of being extremely dynamic in response, in line with the intermittency of renewable energy production. [ABSTRACT FROM AUTHOR]

Marcus Stapf, Ulf Teichgräber, Ingrid Hilger Department of Experimental Radiology, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich-Schiller University Jena, Jena, Germany Abstract: Heat-based approaches have been considered as promising tools due to their ability to directly eradicate tumor cells and/or increase the sensitivity of tumors to radiation- or chemotherapy. In particular, the heating of magnetic nanoparticles (MNPs) via an alternating magnetic field can provide a handy alternative for a localized tumor treatment. To amplify the efficacy of magnetically induced thermal treatments, we elucidated the superior tumor-destructive effect of methotrexate-coupled MNPs (MTX/MNPs) in combination with magnetic heating (nanochemothermia) over the thermal treatment alone. Our studies in a murine bladder xenograft model revealed the enormous potential of nanochemothermia for a localized and relapse-free destruction of tumors which was superior to the thermal treatment alone. Nanochemothermia remarkably fostered the reduction of tumor volume. It impaired proapoptotic signaling (eg, p-p53), cell survival (eg, p-ERK1/2), and cell cycle (cyclins) pathways. Additionally, heat shock proteins (eg, HSP70) were remarkably affected. Moreover, nanochemothermia impaired the induction of angiogenic signaling by decreasing, for example, the levels of VEGF-R1 and MMP9, although an increasing tumor hypoxia was indicated by elevated Hif-1α levels. In contrast, tumor cells were able to recover after the thermal treatments alone. In conclusion, nanochemothermia on the basis of MTX/MNPs was superior to the thermal treatment due to a modification of cellular pathways, particularly those associated with the cellular survival and tumor vasculature. This allowed very efficient and relapse-free destruction of tumors. Keywords: bladder cancer, magnetic heating, magnetic nanoparticles, methotrexate, hyperthermia, mouse xenograft

Effective thawing of cryopreserved samples requires rapid and uniform heating. This is achievable through nanowarming, an approach that heats magnetic nanoparticles by using alternating magnetic fields. Here we demonstrate the synthesis and surface modification of magnetic nanoclusters for efficient nanowarming. Magnetite (Fe 3 O 4 ) nanoclusters with an optimal diameter of 58 nm exhibit a high specific absorption rate of 1499 W/g Fe under an alternating magnetic field at 43 kA/m and 413 kHz, more than twice that of commercial iron oxide cores used in prior nanowarming studies. Surface modification with a permeable resorcinol-formaldehyde resin (RFR) polymer layer significantly enhances their colloidal stability in complex cryoprotective solutions, while maintaining their excellent heating capacity. The Fe 3 O 4 @RFR nanoparticles achieved a high average heating rate of 175 °C/min in cryopreserved samples at a concentration of 10 mg Fe/mL and were successfully applied in nanowarming porcine iliac arteries, highlighting their potential for enhancing the efficacy of cryopreservation.

The study investigated the phenomenon of the fast aggregation of single-domain magnetic iron oxide nanoparticles in stable aqueous colloidal suspensions due to the presence of a radio-frequency (RF) magnetic field. Single-domain nanoparticles have specific magnetic properties, especially the unique property of absorbing the energy of such a field and releasing it in the form of heat. The localized heating causes the colloid to become unstable, leading to faster agglomeration of nanoparticles and, consequently, to rapid sedimentation. It has been shown that the destabilization of a stable magnetic nanoparticle colloid by the RF magnetic field can be used for the controlled filtration of larger agglomerates of the colloid solution. Two particular cases of stable colloidal suspensions were considered: a suspension of the bare nanoparticles in an alkaline solution and the silica-stabilized nanoparticles in a neutral solution. The obtained results are important primarily for biomedical applications and wastewater treatment.

Abstract The main goal of the ENOVHEAT project is to develop, build and test a prototype of an innovative heat pump based on active magnetic regenerator technology. This device can be coupled to a ground source heat exchanger and an under-floor heating system to provide for the space heating needs of a low-energy house in Denmark. However, the use of a simple controller leads to modest performances because the heating system is running mostly part-load. This numerical study has tested the possibility of using heat storage in the indoor environment and building thermal mass as an effective strategy to improve the operation of the magnetocaloric heat pump. Indoor temperature set point modulation can take advantage of the building energy flexibility potential to maximize the full-load operation time of the heating system and therefore improve its seasonal COP. Results show that this control strategy can significantly increase the seasonal COP, ranging from 2.90 to 3.51 depending on the building thermal mass. Although the indoor temperature stability is reduced, it allows the magnetocaloric heat pump to reach energy use efficiencies which are similar to the ones of conventional vapour-compression heat pumps. Highlights • Active magnetic regenerator device integrated in residential buildings as a magnetocaloric heat pump system. • Presentation of a heat storage strategy to improve the operation of the magnetocaloric heat pump. • Heat storage in the indoor environment can increase the performance of a magnetocaloric heat pump integrated in a building. [ABSTRACT FROM AUTHOR]

• Liquid marbles were exposed to the elevated temperature under an alternating magnetic field. • An alternating magnetic field facilitated the evaporation of the ferrofluid core. • Polymer particle shells were partially rigidified after liquid core evaporation. • The rigidified polymer structure acted as a precursor for the next generation of liquid marbles when refilled. • Liquid marbles with varying shapes and shell properties showed responsiveness to a static magnetic field. Liquid marbles, droplets entrapped in a solid particle shell at the air–liquid interface, can respond to stimuli such as alternating magnetic fields. In this study, we examined liquid marbles composed of the ferrofluid core covered by diverse particles, including thermo-responsive polymer microspheres. The temperature elevation induced by an alternating magnetic field provided the particle surface of the marbles with enhanced properties and broadened the functionality of the entire structure. The thermal response partially rigidified the particle shell, and despite temperature-induced evaporation of the liquid core, the residual shell could be easily refilled with an intended cargo, e.g., an additional portion of ferrofluid or an antibiotic suspension. Due to the presence of magnetic particles inside the droplets, liquid marbles were also responsive to static magnetic fields, enabling control over their position and spatial orientation using magnets. We also obtained patchy and Janus structures employing magneto-coalescence of two or more liquid marbles, underscoring the innovative use of alternating magnetic fields to modulate liquid marble properties potentially serving as delivery agents in various applications. [ABSTRACT FROM AUTHOR]

The present study explores the entropy generation, flow, and heat transfer characteristics of a dissipative nanofluid in the presence of transpiration effects at the boundary. The non-isothermal boundary conditions are taken into consideration to guarantee self-similar solutions. The electrically conducting nanofluid flow is influenced by a magnetic field of constant strength. The ultrafine particles (nanoparticles of Fe3O4/CuO) are dispersed in the technological fluid water (H2O). Both the base fluid and the nanofluid have the same bulk velocity and are assumed to be in thermal equilibrium. Tiwari and Dass’s idea is used for the mathematical modeling of the problem. Furthermore, the ultrafine particles are supposed to be spherical, and Maxwell Garnett’s model is used for the effective thermal conductivity of the nanofluid. Closed-form solutions are derived for boundary layer momentum and energy equations. These solutions are then utilized to access the entropy generation and the irreversibility parameter. The relative importance of different sources of entropy generation in the boundary layer is discussed through various graphs. The effects of space free physical parameters such as mass suction parameter (S), viscous dissipation parameter (Ec), magnetic heating parameter (M), and solid volume fraction (ϕ) of the ultrafine particles on the velocity, Bejan number, temperature, and entropy generation are elaborated through various graphs. It is found that the parabolic wall temperature facilitates similarity transformations so that self-similar equations can be achieved in the presence of viscous dissipation. It is observed that the entropy generation number is an increasing function of the Eckert number and solid volume fraction. The entropy production rate in the Fe3O4−H2O nanofluid is higher than that in the CuO−H2O nanofluid under the same circumstances.

Utilization of magnetic nanoparticle-mediated conversion of electromagnetic energy into heat is gaining attention in catalysis as a source of heat needed for a substrate’s chemical reaction (electrification of chemical conversions). We demonstrate that rapid and selective heating of magnetic nanoparticles opens a way to the rapid synthesis of a nanocatalyst. Magnetic heating caused rapid reduction of Ru3+ cations in the vicinity of the support material and enabled preparation of a Ru nanoparticle-bearing nanocatalyst. Comparative synthesis conducted under conventional heating revealed significantly faster Ru3+ reduction under magnetic heating. The faster kinetic was ascribed to the higher surface temperature of the support material caused by rapid magnetic heating. The nanocatalyst was rigorously tested in the hydrotreatment of furfural. The activity, selectivity and stability for furfural hydrogenation to furfuryl alcohol, a valuable biobased monomer, remained high even after four magnetic recycles.

Graphical abstract Highlights • Magnetic nanocomposites with shape memory properties are prepared by a simple casting procedure. • Nanocomposites present super-paramagnetic behavior with mean blocking temperatures between 21 and 27 K. • Nanocomposites' temperature increases when they are exposed to an alternant magnetic field. • Nanocomposites' original shape is recovered by applying magnetic heating as indirect triggering method. • A fast and almost complete recovery of the original shape of the samples containing more than 3 nominal wt.% MNP is obtained. Abstract Shape memory composites based on a commercial segmented polyurethane and magnetite (Fe 3 O 4) nanoparticles (MNPs) were prepared by a simple suspension casting method. The average sizes of individual magnetic particles/clusters were determined by TEM microscopy and corroborated from SAXS patterns. The magnetization properties of selected samples were evaluated using zero field cooling/field cooling (ZFC/FC) measurements and magnetization loops obtained at different temperatures. The results showed that magnetization at high field (20 k Oe) and coercitivity measured at 5 K increase with magnetite content and that all the composite films exhibit superparamagnetic behavior at 300 K. The specific absorption rate (SAR) of the nanocomposites was calculated by experimentally determining both the specific heat capacity and the heating rate of the films exposed to an alternant magnetic field. All nanocomposites were able to increase their temperature when exposed to an alternant magnetic field, although the final temperature reached resulted dependent of the MNPs concentration. What is more, a fast and almost complete recovery of the original shape of the nanocomposites containing more than 3 nominal wt.% MNP was obtained by this remote activation applied to the previously deformed samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • FeZrB MNFs exhibit much higher viscosity under fields compared with Fe 3 O 4 MNFs. • Amorphous FeZrB nanoparticles enable effective specific absorption rate. • MNFs with FeZrB nanoparticles give a larger k enhancement than that with Fe 3 O 4. • The solid-MNF Kapitza resistance significantly influences the k measurement of MNFs. Abstract Magnetic heating and thermal conductivity of magnetic nanofluids (MNFs) are of great interest for biomedicine and electronic heat transfer. Here, we report the enhanced magnetic heating efficiency and thermal conductivity of MNFs fabricated by amorphous FeZrB nanoparticles with high saturation magnetization and good magnetothermal stability. Under external magnetic fields, the viscosities of FeZrB MNFs are almost twice that of Fe 3 O 4 MNFs, enhancing the field-driving force in heat transfer applications. Under 250 Oe alternating current fields, the required time of heating FeZrB MNFs to the hyperthermic temperature (45 °C) is only 16.5% that of Fe 3 O 4 MNFs, amplifying the specific absorption rate of the magnetic nanoparticles by about 2.4 times. Benefiting from the higher thermal conductivity of amorphous, the thermal conductivity enhancement for FeZrB MNFs is also larger than that of Fe 3 O 4 MNFs—up to 34.0% enhancement for silicone oil-based FeZrB MNF at φ = 2 vol%. This investigation of amorphous-nanoparticle-including MNFs shall shed light on the potential of utilizing amorphous nanoparticles to fabricate MNFs for biomedicine or heat management applications. [ABSTRACT FROM AUTHOR]

The EnovHeat project aims at developing an innovative heat pump system based on the magnetocaloric effect and active magnetic regenerator technology to provide for the heating needs of a single family house in Denmark. Unlike vapor-compression devices, magnetocaloric heat pumps use the reversible magnetocaloric effect of a solid refrigerant to build a cooling/heating cycle. It has the potential for high coefficient of performance, more silent operation and efficient part-load control. After presenting the operation principles of the magnetocaloric device and the different models used in the current numerical study, this article demonstrates for the first time the possibility to utilize this novel heat pump in a building. This device can be integrated in a single hydronic loop including a ground source heat exchanger and a radiant under-floor heating system. At maximum capacity, this magnetocaloric heat pump can deliver 2600 W of heating power with an appreciable average seasonal system COP of 3.93. On variable part-load operation with a simple fluid flow controller, it can heat up an entire house with an average seasonal system COP of 1.84. [ABSTRACT FROM AUTHOR]

Whereas the application of optically or magnetically heated nanoparticles to destroy tumours is now well established, the extension of this concept to target pathogens has barely begun. Here we examine the challenge of targeting pathogens by this means and, in particular, explore the issues of power density and heat transfer. Depending on the rate of heating, either hyperthermia or thermoablation may occur. This division of the field is fundamental and implies very different sources of excitation and heat transfer for the two modes, and different strategies for their clinical application. Heating by isolated nanoparticles and by agglomerates of nanoparticles is compared: hyperthermia is much more readily achieved with agglomerates and for large target volumes, a factor which favours magnetic excitation and moderate power densities. In contrast, destruction of planktonic pathogens is best achieved by localised thermoablation and very high power density, a scenario that is best delivered by pulsed optical excitation. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles have been of great interest for various biomedical applications due to their controllability in the distance. Monodisperse superparamagnetic CoFe 2 O 4 (CFO) nanoparticles were synthesized by solvothermal method with oleic acid. The oleic acid ligands are exchanged with citric acid to obtain water-dispersible citric acid-coated CA (CFO–CA) nanoparticles. The M–H curve recorded at room temperature shows the superparamagnetic nature of CFO nanoparticles for both oleic- and citric-coated samples. The magnetic heating performance of CFO–CA shows an exciting dependence on the particle size and surface functionality. The hyperthermia efficiency of CFO–CA nanoparticles increases with increasing magnetic field strength and nanoparticle concentration. A specific absorption ratio value of 152.7 W/g obtained in this study is comparable to other investigations, demonstrating a great potential of CFO–CA nanoparticles for hyperthermia-based treatments. This controlled synthesis process can be applied to various functional biomedical nanoparticles to prepare nanoparticles with designed surface moieties for further potential applications. [Display omitted] • Superparamagnetic CoFe 2 O 4 nanoparticles have been solvothermally synthesized. • CoFe 2 O 4 particle size and magnetic property can be controlled by oleic acid coating. • Ligand exchange has been used to replace oleic acid with citric acid for coating. • Citric acid-coated CoFe 2 O 4 nanoparticles show improvements in magnetic heating. [ABSTRACT FROM AUTHOR]

Abstract Bio-compatible magnetic fluids having high saturation magnetization find immense applications in various biomedical fields. Aqueous ferrofluids of superparamagnetic iron oxide nanoparticles with narrow size distribution, high shelf life and good stability is realized by controlled chemical co-precipitation process. The crystal structure is verified by X-ray diffraction technique. Particle sizes are evaluated by employing Transmission electron microscopy. Room temperature and low-temperature magnetic measurements were carried out with Superconducting Quantum Interference Device. The fluid exhibits good magnetic response even at very high dilution (6.28 mg/cc). This is an advantage for biomedical applications, since only a small amount of iron is to be metabolised by body organs. Magnetic field induced transmission measurements carried out at photon energy of diode laser (670 nm) exhibited excellent linear dichroism. Based on the structural and magnetic measurements, the power loss for the magnetic nanoparticles under study is evaluated over a range of radiofrequencies.

Herein, we have developed nanohybrids (nHs) to remotely activate a therapeutic enzyme for its use in Directed Enzyme Prodrug Therapy (DEPT). The coencapsulation of magnetic nanoparticles (MNPs) with horseradish peroxidase (HRP) using biomimetic silica as an entrapment matrix was optimized to obtain nanosized hybrids (∼150 nm) for remote activation of the therapeutic enzyme. HRP converts indole-3-acetic acid (3IAA) into peroxylated radicals, whereas MNPs respond to alternating magnetic fields (AMFs) becoming local hotspots. The AMF application triggered an increase in the bioconversion rate of HRP matching the activity displayed at the optimal temperature of the nHs ( T opt = 50 °C) without altering the temperature of the reaction media. This showed that enzyme nanoactuation is possible with MNPs even if they are not covalently bound. After an extensive physicochemical/magnetic characterization, the spatial location of each component of the nH was deciphered, and an insulating role of the silica matrix was suggested as critical for introducing remote control over HRP. In vitro assays, using a human pancreatic cancer cell line (MIA PaCa-2), showed that only upon exposure to AMF and in the presence of the prodrug, the enzyme-loaded nHs triggered cell death. Moreover, in vivo experiments showed higher reductions in the tumor volume growth in those animals treated with nHs in the presence of 3IAA when exposed to AMF. Thus, this work demonstrates the feasibility of developing a spatiotemporally controlled DEPT strategy to overcome unwanted off-target effects.

The oxygen evolution reaction (OER) has significant effects on the water-splitting process and rechargeable metal-air batteries; however, the sluggish reaction kinetics caused by the four-electron transfer process for transition metal catalysts hinder large-scale commercialization in highly efficient electrochemical energy conversion devices. Herein, a magnetic heating-assisted enhancement design for low-cost carbonized wood with high OER activity is proposed, in which Ni nanoparticles are encapsulated in amorphous NiFe hydroxide nanosheets (a-NiFe@Ni-CW) via direct calcination and electroplating. The introduction of amorphous NiFe hydroxide nanosheets optimizes the electronic structure of a-NiFe@Ni-CW, accelerating electron transfer and reducing the energy barrier in the OER. More importantly, the Ni nanoparticles located on carbonized wood can function as magnetic heating centers under the effect of an alternating current (AC) magnetic field, further promoting the adsorption of reaction intermediates. Consequently, a-NiFe@Ni-CW demonstrated an overpotential of 268 mV at 100 mA cm -2 for the OER under an AC magnetic field, which is superior to that of most reported transition metal catalysts. Starting with sustainable and abundant wood, this work provides a reference for highly effective and low-cost electrocatalyst design with the assistance of a magnetic field., (© 2023 Wiley-VCH GmbH.)

Magnetic iron oxide nanoparticles (MNPs) have been developed for magnetic fluid hyperthermia (MFH) cancer therapy, where cancer cells are treated through the heat generated by application of a high frequency magnetic field. This heat has also been proposed as a mechanism to trigger release of chemotherapy agents. In each of these cases, MNPs with optimal heating performance can be used to maximize therapeutic effect while minimizing the required dosage of MNPs. In this study, the heating efficiencies (or specific absorption rate, SAR) of two types of MNPs were evaluated experimentally and then predicted from their magnetic properties. MNPs were also incorporated in the core of poly(ethylene glycol- b -caprolactone) micelles, co-localized with rhodamine B fluorescent dye attached to polycaprolactone to monitor local, nanoscale temperatures during magnetic heating. Despite a relatively high SAR produced by these MNPs, no significant temperature rise beyond that observed in the bulk solution was measured by fluorescence in the core of the magnetic micelles. MNPs were also incorporated into a macro-scale agarose gel system that mimicked a tumor targeted by MNPs and surrounded by healthy tissues. The agarose-based tumor models showed that targeted MNPs can reach hyperthermia temperatures inside a tumor with a sufficient MNP concentration, while causing minimal temperature rise in the healthy tissue surrounding the tumor. [ABSTRACT FROM AUTHOR]

Monodisperse magnetite nanospheres with hollow interior and porous shell structure were synthesized through one-pot solvothermal process. The chemical conversions of the Fe (III) compounds to generate Fe 3 O 4 simultaneously coupled with the Ostwald ripening process within the magnetite spheres were considered as underlying mechanism for evolution of the Fe 3 O 4 porous/hollow nanostructure. The morphology of Fe 3 O 4 nanoparticles could be controlled by adjusting the conditions of process variables. We investigated their potential in hyperthermia-based treatments, using an alternative magnetic field. Our study revealed that higher applied frequency resulted in the higher heat generation and thus faster temperature growth. The hyperthermia efficiency of the Fe 3 O 4 nanoparticles generally depended on particle structures and magnetic properties. The Fe 3 O 4 porous/hollow nanoparticles also exhibited an excellent heat generation for several continuous cycles of applied field for a long time. [ABSTRACT FROM AUTHOR]

Manganese ferrite nanoparticles were synthesized using the reverse micelle method; these particles were then coated with silica. The silica-coated nanoparticles were spherical in shape, with an average diameter of 14 nm. The inverse spinel crystalline structure was observed through X-ray diffraction patterns. The coating status of silica on the surface of the nanoparticles was confirmed with a Fourier transform infrared spectrometer. The superparamagnetic properties were revealed by the zero coercive force in the hysteresis curve. Controllable heating at a fixed temperature of 42 °C was achieved by changing either the concentration of nanoparticles in the aqueous solution or the intensity of the alternating magnetic field. We found that at a fixed field strength of 5.5 kA/m, the 2.6 mg/ml sample showed a saturation temperature of 42 °C for magnetic hyperthermia. On the other hand, at a fixed concentration of 3.6 mg/ml, a field intensity of 4.57 kA/m satisfied the required temperature of 42 °C. [ABSTRACT FROM AUTHOR]

Recently, potential applications of the magnetic heating for heterogeneous catalysis or organic synthesis have been reported. As these new applications are not limited by biocompatibility requirements, a wide range of possibilities for non-aqueous colloidal nanoparticles with enhanced magnetic properties is open. In this work, manganese and cobalt ferrite nanoparticles are synthesized by co-precipitation method with average particle size around 12 nm. The particles are either coated with tetramethylammonium hydroxide (TMAOH) and dispersed in water or with oleic acid (OA) and dispersed in hexane to produce aggregated or disaggregated nanoparticles, respectively. It is observed that the particle disaggregation improves significantly the heating efficiency from 12 to 96 W/g in the case of cobalt ferrite, and from 120 to 413 W/g for the manganese ferrite. The main responsible for this improvement is the reduction of hydrodynamic volume that allows a faster Brownian relaxation. This work also discusses the relevance of the size distribution. [ABSTRACT FROM AUTHOR]

Microwave heating is rapidly emerging as an effective and efficient tool in various technological and scientific fields. A comprehensive understanding of the fundamentals of microwave-matter interactions is the precondition for better utilization of microwave technology. However, microwave heating is usually only known as dielectric heating, and the contribution of the magnetic field component of microwaves is often ignored, which, in fact, contributes greatly to microwave heating of some aqueous electrolyte solutions, magnetic dielectric materials and certain conductive powder materials, etc. This paper focuses on this point and presents a careful review of microwave heating mechanisms in a comprehensive manner. Moreover, in addition to the acknowledged conventional microwave heating mechanisms, the special interaction mechanisms between microwave and metal-based materials are attracting increasing interest for a variety of metallurgical, plasma and discharge applications, and therefore are reviewed particularly regarding the aspects of the reflection, heating and discharge effects. Finally, several distinct strategies to improve microwave energy utilization efficiencies are proposed and discussed with the aim of tackling the energy-efficiency-related issues arising from the application of microwave heating. This work can present a strategic guideline for the developed understanding and utilization of the microwave heating technology. [ABSTRACT FROM AUTHOR]

Ferrofluids are nanomaterials consisting of magnetic nanoparticles that are dispersed in a carrier fluid. Their physical properties, and hence their field of application are determined by intertwined compositional, structural, and magnetic characteristics, including interparticle magnetic interactions. Magnetic nanoparticles were prepared by thermal decomposition of iron(III) chloride hexahydrate (FeCl3·6H2O) in 2-pyrrolidone, and were then dispersed in two different fluids, water and polyethylene glycol 400 (PEG). A number of experimental techniques (especially, transmission electron microscopy, Mössbauer spectroscopy and superconducting quantum interference device (SQUID) magnetometry) were employed to study both the as-prepared nanoparticles and the ferrofluids. We show that, with the adopted synthesis parameters of temperature and FeCl3 relative concentration, nanoparticles are obtained that mainly consist of maghemite and present a high degree of structural disorder and strong spin canting, resulting in a low saturation magnetization (~45 emu/g). A remarkable feature is that the nanoparticles, ultimately due to the presence of 2-pyrrolidone at their surface, are arranged in nanoflower-shape structures, which are substantially stable in water and tend to disaggregate in PEG. The different arrangement of the nanoparticles in the two fluids implies a different strength of dipolar magnetic interactions, as revealed by the analysis of their magnetothermal behavior. The comparison between the magnetic heating capacities of the two ferrofluids demonstrates the possibility of tailoring the performances of the produced nanoparticles by exploiting the interplay with the carrier fluid.

Macroscopic 3D porous materials are ideal solar evaporators for water purification. However, the limited sunlight intensity and penetrating depth during solar-driven evaporation cannot prevent the biofouling formation by photothermal effect, thus leading to the deterioration of evaporation rate. Herein, a magnetic heating strategy is reported for anti-biofouling solar steam generation based on a magnetic silk fibroin (SF) scaffold with bi-heating property. Under one sun, the solar-heated top surface of magnetic SF scaffolds accelerates water evaporation at 2.03 kg m -2 h -1 , while the unheated inner channels suffer from the formation of biofilm. When exposed to alternating magnetic field (AMF), the magnetic SF scaffold can be integrally heated, leading to an efficient inner temperature to prevent biofouling in channels for water transportation. Accordingly, magneto-heated scaffolds show steady water evaporation rates after exposure to S. aureus and E. coli, which maintained 93.6-94.6% of original performance. In contrast, the evaporation rates of the scaffolds without AMF treatment are reduced to 1.31 (S. aureus) and 1.32 (E. coli) kg m -2 h -1 , decreased by 35.5% and 35.0%, respectively. In addition, the magneto-heated scaffold inhibits biofouling formation in natural lake water, maintaining 99.5% original performance., (© 2023 Wiley-VCH GmbH.)

The magnetic heating treatment (MHT) is well known as a promising therapy for cancer diseases. Depending on concentration and specific heating power of the magnetic material as well as on parameters of the magnetic field, temperatures between 43 and 55 °C can be reached. This paper deals with the evaluation of heat distribution around such a heat source in a tissue model, thereby focusing on the heat transfer from tissue enriched with magnetic nanoparticles to regions of no or little enrichment of magnetic nanoparticles. We examined the temperature distribution with several tissue phantoms made of polyurethane (PUR) with similar thermal conductivity coefficient as biological tissue. These phantoms are composed of a cylinder with one sphere embedded, enriched with magnetic fluid. Thereby the spheres have different diameters in order to study the influence of the surface-to-volume ratio. The phantoms were exposed to an alternating magnetic field. The magnetically induced heat increase within the phantoms was measured with thermocouples. Those were placed at defined positions inside the phantoms. Based on the measured results a 3-dimensional simulation of each phantom was built. We achieved an agreement between the measured and simulated temperatures for all phantoms produced in this experimental study. The established experiment theoretically allows a prediction of temperature profiles in tumors and the surrounding tissue for the potential cancer treatment and therefore an optimization of e.g. the respective magnetic nanoparticles concentrations for the desirable rise of temperature. [ABSTRACT FROM AUTHOR]

Eco-friendly magnetophotothermal sponge for efficient recovery of highly viscous crude oil. [Display omitted] • An eco-friendly sponge with dual functionality of magnetic and photothermal heating for efficient recovery of heavy oil spill. • All the feedstock is biocompatible and the fabrication process is energy saving. • Superior magnetic-thermal and photo-thermal effect are demonstrated. • Fast oil recovery rate of 289.4 g h−1 cm−2 for heavy oil with viscosity of 6.2 × 104 mPa s and 50.6 g h−1 cm−2 for heavy oil with viscosity of 3.3 × 105 mPa s. The green remediation of crude oil spills is a global concern due to the high viscosity and low fluidity of such oil. Sorbents with heating functions are promising candidates for reducing the viscosity of crude oil and accelerating its cleanup. Herein, we introduce an eco-friendly sponge with the dual functionality of magnetic and photothermal heating for the rapid recovery of heavy oil spills with very high viscosity. The magneto-photothermal sponge was fabricated by the facile dip-coating of magnetoferritin (MPfFn) nanoparticles, polydopamine (PDA), and polydimethylsiloxane (PDMS) on a melamine sponge (MS). The resulting PDMS-MPfFn-MS exhibited excellent hydrophobicity and adequate flame-retardancy. Owing to the electromagnetic–thermal and photothermal conversion properties of the MPfFn/PDA coating, the surface of the functionalized sponge could be rapidly heated to 112.5 °C under alternating magnetic field (f = 502.05 kHz, H = 10.5 kA m−1) or 81.9 °C under light illumination (1 kW m−2). The fast and continuous recovery of extremely highly viscous oil was realized by a combination of solar and magnetic heating with a vacuum pump, and the recovery rate reached 50.6 g h−1 cm−2. The proposed approach integrates the safety and temperature controllability of magnetic heating and the energy-saving feature of solar heating, thereby serving as a new solution for addressing viscous crude oil spills. [ABSTRACT FROM AUTHOR]