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GestureMeter: Design and Evaluation of a Gesture Password Strength Meter
No full textGestures drawn on touchscreens have been proposed as an authentication method to secure access to smartphones. They provide good usability and a theoretically large password space. However, recent work has demonstrated that users tend to select simple or similar gestures as their passwords, rendering them susceptible to dictionary based guessing attacks. To improve their security, this paper describes a novel gesture password strength meter that interactively provides security assessments and improvement suggestions based on a scoring algorithm that combines a probabilistic model, a gesture dictionary, and a set of novel stroke heuristics. We evaluate this system in both online and offline settings and show it supports creation of gestures that are significantly more resistant to guessing attacks (by up to 67%) while also maintaining performance on usability metrics such as recall success rate and time. We conclude that gesture password strength meters can help users select more secure gesture passwords. ?? 2023 ACM
MicroRNA-29 Ameliorates Fibro-Inflammation and Insulin Resistance in HIF1??-Deficient Obese Adipose Tissue by Inhibiting Endotrophin Generation
No full textThe metabolic roles of type VI collagen and its cleavage peptide endotrophin in obese adipose tissue (AT) are well established. However, the mechanisms regulating endotrophin generation remain elusive. Herein, we identified that several endotrophin containing peptides were generated from the COL6A3 chain through the action of hypoxia-induced matrix metalloproteinases. Hypoxia is an upstream regulator of COL6A3 expression and the proteolytic processing that regulates endotrophin generation. Hypoxia-inducible factor 1?? and the hypoxia-associated suppression of microRNA-29 cooperatively control the levels of COL6A3 and MMPs, responsible for endotrophin generation in hypoxic ATs. Adipocyte-specific Hif1?? knock-out (APN-HIF1??KO) mice fed a chronic high-fat diet exhibited the significant amelioration of both local fibro-inflammation in AT and systemic insulin resistance compared with their control littermates, partly through the inhibition of endotrophin generation. Strikingly, adenovirus-mediated miR-29 overexpression in the ATs of APN-HIF1??KO mice in obesity significantly decreased endotrophin levels
Solid-State Synthesis and Optical Studies of Water-Stable Pb<sup>2+</sup>-Doped Mn<sup>2+</sup> Complexes
No full textThe limited Mn2+ doping that occurs in lead halide perovskites has been widely described, while the Pb2+ doping that occurs in Mn2+ halide perovskites has not been studied well. Generally, a large amount of doping of Mn2+ in lead halide perovskite degrades the perovskite structure; eventually, high orange luminescence of Mn2+ dopant has not been achieved. In our present study, we followed a reverse strategy, i.e., Pb2+ doping in Mn2+ halide perovskites, to increase the amount of Mn2+ in halide perovskites through the high-energy ball milling method. This strategy yields bright-fluorescence orange light-emitting Mn2+-doped perovskite with a Mn/Pb ratio of 95%, which is the highest among Mn2+-doped perovskites. Zero-dimensional (0D) Mn2+ perovskites and two-dimensional (2D) Pb2+-doped Mn2+-based perovskites were successfully synthesized and characterized. During the mechanochemical engineering, Pb2+ ions partially occupy the site of Mn2+ ions and act as a luminescence activator. Mn2+-based 2D perovskites with the proper amounts of Pb2+ ions as dopant ions and phenylethylammonium (PEA(+)) as dielectric organic cations show enhanced stability in water. The dual-emissive properties of these 2D-Pb2+-doped Mn2+-based perovskites were also investigated by using single-particle imaging fluorescence. We believe that these findings will pave the way for designing eco-friendly dimension and bandgap tunable layered perovskites
First-Principles Study on the Electronic and Mechanical Properties of the Cr(001)/Al(001) Structure
No full textWe utilized spin-polarized density functional theory to analyze the properties of the Cr(001)/Al(001) structure. The interface was classified into three forms-bcc, bridge, and top-based on the bonding coordinates between Cr and Al atoms. The total density of states (DOS) of the structures is mainly influenced by the Cr (d) orbitals. The local DOS of the Cr atoms at the interface exhibits slight variations based on their coordination with neighboring Al atoms. The mechanical properties of a specific layer were analyzed by using the rigid grain shift (RGS) method, and the properties of all layers were analyzed by using the homogeneous lattice extension method. Our results confirmed that the bonding strength, as determined by the RGS method, follows a decreasing order from the strongest to the weakest: bcc, bridge, and top. We applied uniform deformation to the entire system in the thickness direction and allowed it to relax: we observed that deformation occurs mainly in the Al region and ultimately leads to failure regardless of the type of interface. Consequently, similar strain-stress curves were observed in all Cr(001)/Al(001) structures. The failure in the Al region is attributed to the lower stiffness of the Al-Al layers compared to the top interface despite the lower work of separation for the top interface
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Coating lithium titanate anodes with a mixed ionic-electronic conductor for high-rate lithium-ion batteries
No full textLithium titanate (Li4Ti5O12; LTO) is a promising anode material for fast (dis)charging Li-ion batteries (LIBs). However, its low Li diffusion coefficient and electronic conductivity limit its applications. Here, we uniformly coat the LTO surface with a 1.6 nm layer of partially lithiated titania (LixTiO2, x approximate to 0.5), which is found to be a mixed ionic-electronic conductor (MIEC), using a simple solid-state method. The MIEC layer simultaneously transfers electrons and Li-ions, facilitating efficient charge transfer to (de)lithiate LTO over the entire particle surface. MIEC-nanocoated LTO exhibits highly improved capacity retention and rate capability than pristine LTO; based on electrochemical simulations, MIEC nanocoating causes performance enhancement by maximum surface-area utilization for charge transfer. Furthermore, electrochemical impedance spectroscopy and density functional theory calculations confirm facile ionic transport and high electronic conductivity of LixTiO2 nano -layer. This general strategy of MIEC nanocoating can boost the electrochemical performances of various insu-lating electrodes, maximizing the materials utilization
Unveiling Hidden Zeolitic Imidazolate Frameworks Guided by Intuition???Based Geometrical Factors
No full textHerein, synthesizable candidate topologies to form zeolitic imidazolate frameworks (ZIFs) are efficiently identified from over 2 000 000 hypothetical structures in zeolite databases, using structural descriptors extracted from known ZIFs. A combination of intuition-based structural descriptors, such as ring patterns, node numbers, and T???O???T bridging angles (T = tetrahedral metal nodes in zeolites and ZIFs), is used as data filters to eliminate topologies infeasible for ZIF formation. Carefully chosen structural descriptors facilitate the prediction of plausible ZIF topologies. To investigate potential applications as porous ZIFs, this work performs hydrogen adsorption screening and suggested notable target ZIFs. The collection of new plausible ZIFs, derived from the combined descriptors, will be a structural blueprint for synthetic chemists
Heterometallic Gd-Dy Formate Frameworks for Enhanced Magnetocaloric Properties
No full textLanthanide-based metal-organic frameworks (MOFs) have great potential as magnetic refrigerants under cryogenic conditions and are comparable to conventional alloys and magnetic nanoparticles. In particular, MOFs with Gd3+ ions behave as excellent magnetic refrigerants because of their large spin ground states. However, the major drawback of Gd3+-based MOFs is that they are not affected by the ligand material owing to the excessively large spin-only magnetic moment; therefore, their application is limited to the cryogenic region in the magnetic cooling field. In this study, we report the magnetic properties and magnetocaloric effect (MCE) resulting from heterogenized MOFs obtained from the reaction of Gd3+ and Dy3+ ions and their varied molar composition with the formate ligand. For GdxDy1-x-(HCOO)3, where 0 < x < 1, the isothermal magnetic entropy change (Delta Sm) increased with the increase in the fraction of Gd in the heterogenized MOFs. Meanwhile, with increasing Dy contents, the maximum peak temperature of Delta Sm is shifted to a higher temperature while preserving a relatively high Delta Sm value of 22.35 J center dot kg-1 K-1 at T = 7 K for an applied field change (Delta H) of 7 T despite the anisotropy and crystalline electric field effects. Furthermore, it was confirmed that the samples with a Dy content of 75% or more maintained the Delta Sm operating temperature longer. Therefore, the current approach of including Dy3+ ions in lanthanide compounds provides the possibility of further extending the operating temperature of magnetic cooling materials from cryogenic temperatures
Cosmic-Ray Acceleration and Nonthermal Radiation at Accretion Shocks in the Outer Regions of Galaxy Clusters
No full textCosmology models predict that external accretion shocks form in the outer region of galaxy clusters owing to supersonic gas infall from filaments and voids in the cosmic web. They are characterized by high sonic and Alfvenic Mach numbers, M ( s ) similar to 10-10(2) and M (A) similar to 10(2)-10(3), and propagate into weakly magnetized plasmas of beta equivalent to P ( g )/P ( B ) greater than or similar to 10(2). Although strong accretion shocks are expected to be efficient accelerators of cosmic rays (CRs), nonthermal signatures of shock-accelerated CRs around clusters have not been confirmed, and detailed acceleration physics at such shocks has yet to be understood. In this study, we first establish through two-dimensional particle-in-cell simulations that at strong high-beta shocks electrons can be pre-energized via stochastic Fermi acceleration owing to the ion Weibel instability in the shock transition region, possibly followed by injection into diffusive shock acceleration. Hence, we propose that the models derived from conventional thermal leakage injection may be employed for the acceleration of electrons and ions at accretion shocks as well. Applying these analytic models to numerical shock zones identified in structure formation simulations, we estimate nonthermal radiation, such as synchrotron and inverse Compton (IC) emission due to CR electrons and pi (0)-decay gamma-rays due to CR protons, around simulated clusters. Our models with injection parameter Q approximate to 3.5-3.8 predict synthetic synchrotron maps, which seem consistent with recent radio observations of the Coma Cluster. However, the detection of nonthermal IC X-rays and gamma-rays from accretion shocks would be quite challenging. We suggest that the proposed analytic models may be adopted as generic recipes for CR production at cosmological shocks