Giant Magnetic Heat Induction of Magnesium‐Doped γ‐Fe2O3 Superparamagnetic Nanoparticles for Completely Killing Tumors

Magnetic fluid hyperthermia has been recently considered as a Renaissance of cancer treatment modality due to its remarkably low side effects and high treatment efficacy compared to conventional chemotheraphy or radiotheraphy. However, insufficient AC induction heating power at a biological safe range of AC magnetic field (H_appl·f_appl < 3.0–5.0 × 10⁹ A m^?1 s^?1), and highly required biocompatibility of superparamagnetic nanoparticle (SPNP) hyperthermia agents are still remained as critical challenges for successful clinical hyperthermia applications. Here, newly developed highly biocompatible magnesium shallow doped γ‐Fe₂O₃ (Mg_0.13‐γFe₂O₃) SPNPs with exceptionally high intrinsic loss power (ILP) in a range of 14 nH m² kg^?1, which is an ≈100 times higher than that of commercial Fe₃O₄ (Feridex, ILP = 0.15 nH m² kg^?1) at H_appl·f_appl = 1.23 × 10⁹ A m^?1 s^?1 are reported. The significantly enhanced heat induction characteristics of Mg_0.13‐γFe₂O₃ are primarily due to the dramatically enhanced out‐of‐phase magnetic susceptibility and magnetically tailored AC/DC magnetic softness resulted from the systematically controlled Mg²⁺ cations distribution and concentrations in octahedral site Fe vacancies of γ‐Fe₂O₃ instead of well‐known Fe₃O₄ SPNPs. In vitro and in vivo magnetic hyperthermia studies using Mg_0.13‐γFe₂O₃ nanofluids are conducted to estimate bioavailability and biofeasibility. Mg_0.13‐γFe₂O₃ nanofluids show promising hyperthermia effects to completely kill the tumors.     

Facile Synthesis of γ‐In2Se3 Nanoflowers toward High Performance Self‐Powered Broadband γ‐In2Se3/Si Heterojunction Photodiode

An effective colloidal process involving the hot‐injection method is developed to synthesize uniform nanoflowers consisting of 2D γ‐In₂Se₃ nanosheets. By exploiting the narrow direct bandgap and high absorption coefficient in the visible light range of In₂Se₃, a high‐quality γ‐In₂Se₃/Si heterojunction photodiode is fabricated. This photodiode shows a high photoresponse under light illumination, short response/recovery times, and long‐term durability. In addition, the γ‐In₂Se₃/Si heterojunction photodiode is self‐powered and displays a broadband spectral response ranging from UV to IR with a high responsivity and detectivity. These excellent performances make the γ‐In₂Se₃/Si heterojunction very interesting as highly efficient photodetectors.     

Patterning π‐Conjugated Polymers

π‐Conjugated polymers show promise as active materials in application areas such as microelectronics, electro‐optics, opto‐electronics, and photonics. A critical feature in this emerging technology is device fabrication and the reproducible deposition of active material. This review focuses on current trends in the spatial deposition of conjugated polymers.     

Oxidation protective coatings for γ‐TiAl – recent trends

Engine designers show continued interest in γ‐TiAl based titanium aluminides as light–weight structural materials to be used at moderately elevated temperatures. Although alloy development has made significant progress in terms of mechanical properties and environmental resistance, protective coatings have been developed that help to extend the lifetime of these alloys significantly. The major challenge of coating development is to prevent the formation of fast growing titania. Furthermore, changes of coating chemistries at high temperatures have to be considered in order to avoid rapid degradation of the coatings due to interdiffusion between substrate and coating. The paper describes recent work of the authors on different coatings produced by means of magnetron sputter technique. Thin ceramic Ti‐Al‐Cr‐Y‐N layers tested at 900 °C exhibited poor oxidation resistance. In contrast, intermetallic Ti‐Al‐Cr, Si‐based and aluminum rich Ti‐Al coatings were tested at exposure temperatures up to 950 °C for 1000h resulting in reasonable and partially excellent oxidation behaviour.     

Nitrogen Doped γ‐Graphyne: A Novel Anode for High‐Capacity Rechargeable Alkali‐Ion Batteries

High energy density is the major demand for next‐generation rechargeable batteries, while the intrinsic low alkali metal adsorption of traditional carbon–based electrode remains the main challenge. Here, the mechanochemical route is proposed to prepare nitrogen doped γ‐graphyne (NGY) and its high capacity is demonstrated in lithium (LIBs)/sodium (SIBs) ion batteries. The sample delivers large reversible Li (1037 mAh g^?1) and Na (570.4 mAh g^?1) storage capacities at 100 mA g^?1 and presents excellent rate capabilities (526 mAh g^?1 for LIBs and 180.2 mAh g^?1 for SIBs) at 5 A g^?1. The superior Li/Na storage mechanisms of NGY are revealed by its 2D morphology evolution, quantitative kinetics, and theoretical calculations. The effects on the diffusion barriers (E_b) and adsorption energies (E_ad) of Li/Na atoms in NGY are also studied and imine‐N is demonstrated to be the ideal doping format to enhance the Li/Na storage performance. Besides, the Li/Na adsorption routes in NGY are optimized according to the experimental and the first‐principles calculation results. This work provides a facile way to fabricate high capacity electrodes in LIBs/SIBs, which is also instructive for the design of other heteroatomic doped electrodes.     

Mechanochemical Synthesis of γ‐Graphyne with Enhanced Lithium Storage Performance

γ‐Graphyne is a new nanostructured carbon material with large theoretical Li⁺ storage due to its unique large conjugate rings, which makes it a potential anode for high‐capacity lithium‐ion batteries (LIBs). In this work, γ‐graphyne‐based high‐capacity LIBs are demonstrated experimentally. γ‐Graphyne is synthesized through mechanochemical and calcination processes by using CaC₂ and C₆Br₆. Brunauer–Emmett–Teller, atomic force microscopy, X‐ray photoelectron spectroscopy, solid‐state ¹³C NMR and Raman spectra are conducted to confirm its morphology and chemical structure. The sample presents 2D mesoporous structure and is exactly composed of sp and sp²‐hybridized carbon atoms as the γ‐graphyne structure. The electrode shows high Li⁺ storage (1104.5 mAh g^?1 at 100 mA g^?1) and rate capability (435.1 mAh g^?1 at 5 A g^?1). The capacity retention can be up to 948.6 (200 mA g^?1 for 350 cycles) and 730.4 mAh g^?1 (1 A g^?1 for 600 cycles), respectively. These excellent electrochemical performances are ascribed to the mesoporous architecture, large conjugate rings, enlarged interplanar distance, and high structural integrity for fast Li⁺ diffusion and improved cycling stability in γ‐graphyne. This work provides an environmentally benign and cost‐effective mechanochemical method to synthesize γ‐graphyne and demonstrates its superior Li⁺ storage experimentally.     

High Detectivity Solar‐Blind High‐Temperature Deep‐Ultraviolet Photodetector Based on Multi‐Layered (l00) Facet‐Oriented β‐Ga2O3 Nanobelts

Fabrication of a high‐temperature deep‐ultraviolet photodetector working in the solar‐blind spectrum range (190–280 nm) is a challenge due to the degradation in the dark current and photoresponse properties. Herein, β‐Ga₂O₃ multi‐layered nanobelts with (l00) facet‐oriented were synthesized, and were demonstrated for the first time to possess excellent mechanical, electrical properties and stability at a high temperature inside a TEM studies. As‐fabricated DUV solar‐blind photodetectors using (l00) facet‐oriented β‐Ga₂O₃ multi‐layered nanobelts demonstrated enhanced photodetective performances, that is, high sensitivity, high signal‐to‐noise ratio, high spectral selectivity, high speed, and high stability, importantly, at a temperature as high as 433 K, which are comparable to other reported semiconducting nanomaterial photodetectors. In particular, the characteristics of the photoresponsivity of the β‐Ga₂O₃ nanobelt devices include a high photoexcited current (>21 nA), an ultralow dark current (below the detection limit of 10^?14 A), a fast time response (<0.3 s), a high R_λ (≈851 A/W), and a high EQE (～4.2 × 10³). The present fabricated facet‐oriented β‐Ga₂O₃ multi‐layered nanobelt based devices will find practical applications in photodetectors or optical switches for high‐temperature environment.     

H+‐Insertion Boosted α‐MnO2 for an Aqueous Zn‐Ion Battery

Rechargeable Zn/MnO₂ batteries using mild aqueous electrolytes are attracting extensive attention due to their low cost, high safety, and environmental friendliness. However, the charge‐storage mechanism involved remains a topic of controversy so far. Also, the practical energy density and cycling stability are still major issues for their applications. Herein, a free‐standing α‐MnO₂ cathode for aqueous zinc‐ion batteries (ZIBs) is directly constructed with ultralong nanowires, leading to a rather high energy density of 384 mWh g^?1 for the entire electrode. Greatly, the H⁺/Zn²⁺ coinsertion mechanism of α‐MnO₂ cathode for aqueous ZIBs is confirmed by a combined analysis of in situ X‐ray diffractometry, ex situ transmission electron microscopy, and electrochemical methods. More interestingly, the Zn²⁺‐insertion is found to be less reversible than H⁺‐insertion in view of the dramatic capacity fading occurring in the Zn²⁺‐insertion step, which is further evidenced by the discovery of an irreversible ZnMn₂O₄ layer at the surface of α‐MnO₂. Hence, the H⁺‐insertion process actually plays a crucial role in maintaining the cycling performance of the aqueous Zn/α‐MnO₂ battery. This work is believed to provide an insight into the charge‐storage mechanism of α‐MnO₂ in aqueous systems and paves the way for designing aqueous ZIBs with high energy density and long‐term cycling ability.     

Modelling three‐dimensional piece‐wise homogeneous domains using the α‐shape‐based natural element method

In this paper, the application of the natural element method (NEM) to the numerical analysis of two‐ and three‐dimensional piece‐wise homogeneous domains is presented. The NEM differs from other meshless methods in its capability to accurately reproduce essential boundary conditions along convex boundaries. The α‐shape‐based extension of this method (α‐NEM) generalizes this behaviour to non‐convex domains, enables us to construct models entirely in terms of the initial cloud of points and allows us to simulate material discontinuities in a straightforward manner. In the following sections, simple and effective algorithms are presented for the construction of α‐shapes in domains composed of various materials. Examples are presented in two‐ and three‐dimensional cases in the context of linear elastostatics showing good performance even with the simple numerical quadrature used. Copyright © 2002 John Wiley & Sons, Ltd.     

Identification of the anthelix motif in the TGF‐β superfamily by molecular 3D‐Rapid Prototyping

3D‐Rapid Prototyping (3D‐RP) is a novel technique for the construction of highly accurate three‐dimensional polyamide models of biomolecules. This method has been shown to be a valuable tool in the modeling of protein‐protein‐interactions as well as in the analysis of surface topography. Using this technique we were recently able to identify a so far unknown structure on the concave side of bone morphogenetic protein 2 (BMP‐2). Since this structure is the imprint of a left‐handed helix we have called this negative an unthelix. Obviously this novel structural feature of BMP‐2 may act as a binding side for endogenous ligands. BMP‐2 belongs to the highly conserved Transforming Growth Factor‐β (TGF‐β) superfamily, a large group of multifunctional peptides controlling differentiation, proliferation and repair in multicellular organism. The protomer structures of all members share a cystine‐knot motif as a characteristic feature. The question therefore arose whether a) the novel anthelical motif found in BMP‐2 is a common structural feature of this family and b) if there are any differences in terms of pitch and radius of the anthelix. As anthelical structures are difficult to visualize and nearly impossible to quantify using 3D molecular visualization software we constructed models of BMP‐2, BMP‐7 and TGF‐β2 from X‐ray crystallographic data by 3D‐Rapid Prototyping (3D‐RP). The anthelix motif was found in BMP‐2, BMP‐7 and TGF‐β2 with similar values for pitch (ca. 8‐10 nm) and radius (ca. 0.5‐0.7 nm). In contrast the anthelical motif was not found in a 3D‐RP model of human chorionic gonadotropin (HCG) which is also a member of the cystine‐knot family but doesn’t belong to the TGF‐β superfamily. These results were corroborated by measurements of the intersubunit angle of these dimeric proteins (141‐149°) and the distances between the center of mass (1.68‐1.96 nm) of the subunits both of which appear to be determinants of the anthelical pitch. We conclude that the anthelical groove on the concave side is a common structural motif of BMP‐2, BMP‐7 and TGF‐β2 and maybe of the whole group of the TGF‐β superfamily.     

Coaggregation of κ‐Casein and β‐Lactoglobulin Produces Morphologically Distinct Amyloid Fibrils

The unfolding, misfolding, and aggregation of proteins lead to a variety of structural species. One form is the amyloid fibril, a highly aligned, stable, nanofibrillar structure composed of β‐sheets running perpendicular to the fibril axis. β‐Lactoglobulin (β‐Lg) and κ‐casein (κ‐CN) are two milk proteins that not only individually form amyloid fibrillar aggregates, but can also coaggregate under environmental stress conditions such as elevated temperature. The aggregation between β‐Lg and κ‐CN is proposed to proceed via disulfide bond formation leading to amorphous aggregates, although the exact mechanism is not known. Herein, using a range of biophysical techniques, it is shown that β‐Lg and κ‐CN coaggregate to form morphologically distinct co‐amyloid fibrillar structures, a phenomenon previously limited to protein isoforms from different species or different peptide sequences from an individual protein. A new mechanism of aggregation is proposed whereby β‐Lg and κ‐CN not only form disulfide‐linked aggregates, but also amyloid fibrillar coaggregates. The coaggregation of two structurally unrelated proteins into cofibrils suggests that the mechanism can be a generic feature of protein aggregation as long as the prerequisites for sequence similarity are met.     

The effect of heat treatment on superconductivity of Zn‐doped YBa2Cu3‐xZnxO7‐y

YBa₂Cu_3‐xZn_xO_7‐y compounds with x = 0, 0.05, 0.15, and 0.30 have been synthesized by standard solid state reaction method. The crystal structure, lattice parameters, and oxygen content are not changed by the substitution of Zn for Cu since both valence state and ionic radius are almost identical for Zn and Cu elements in YBa₂Cu_3‐xZn_xO_7‐y. However, the superconducting transition temperature T_c decreases with the increase of Zn content, reflecting the T_c‐suppression effect of Zn substitution. Heat treatment experiments indicate that the heat treatment at low temperature is beneficial to improve the superconductivity of the sample. But T_c decreases with the increase of annealing temperature when the treatment temperature is above 300°C, and finally the superconductivity disappears at approximately 920°C, 700°C and 550°C for the samples with x = 0.0, 0.05 and 0.15, respectively. Our experiments indicate that the superconductivity of the sample with higher Zn content is more sensitive to the oxygen content, and a small decrease in the oxygen content can lead to a considerable decrease of T_c.