BINA

We perform numerical studies of a thermally driven, overdamped particle in a random quenched force field, known as the Sinai model. We compare the unbounded motion on an infinite 1-dimensional domain to the motion in bounded domains with reflecting boundaries and show that the unbounded motion is at every time close to the equilibrium state of a finite system of growing size. This is due to time scale separation: Inside wells of the random potential, there is relatively fast equilibration, while the motion across major potential barriers is ultraslow. Quantities studied by us are the time dependent mean squared displacement, the time dependent mean energy of an ensemble of particles, and the time dependent entropy of the probability distribution. Using a very fast numerical algorithm, we can explore times up top steps and thereby also study finite-time crossover phenomena.

Carbon aerogels have been studied in the context of fuel cell electrodes mainly as catalyst support materials due to their high surface area, porosity, and electrical conductivity. Recently, aerogels composed solely of inorganic molecular complexes have shown to be promising materials for the electrocatalysis of oxygen reduction reaction (ORR). These aerogels consist of atomically dispersed catalytic sites. Herein, we report on the synthesis and characterization of an aerogel-based catalyst: iron phthalocyanine aerogel. It was synthesized by coupling of ethynyl-terminated phthalocyanine monomers and then heat-treated at 800 °C to increase its electrical conductivity and catalytic activity. The aerogels reported here were tested as catalysts for ORR in acidic conditions for the first time and found to have a ultra-high number of atomically dispersed catalytic sites (7.11 × 1020 sites g–1) and very good catalytic activity (E …

Integrated microwave photonic filters are becoming increasingly important for signal processing within advanced wireless and cellular networks. Filters with narrow transmission passbands mandate long time delays, which are difficult to accommodate within photonic circuits. Long delays may be obtained through slow moving acoustic waves instead. Input radio-frequency information can be converted from one optical carrier to another via surface acoustic waves and filtered in the process. However, the transfer functions of previously reported devices consisted of multiple periodic passbands, and the selection of a single transmission band was not possible. In this work, we demonstrate surface acoustic wave, silicon-photonic filters of microwave frequency with a single transmission passband. The filter response consists of up to 32 tap coefficients, and the transmission bandwidth is only 7 MHz. The results extend the capabilities of integrated microwave photonics in the standard silicon-on-insulator platform.

Developing high performance, cost-effective, and durable electrocatalysts that must be derived from non-noble metals is crucial for alkaline oxygen evolution reaction (OER). OER, which takes place at the anode, is accepted as a major obstacle for commercialization due to its sluggish kinetics. In this study, a two-step synthesis method, such as a hydrothermal process followed by the annealing of the reactants in an Ar-filled Swagelok cell, is briefly described to obtain a cubic type of Co3O4 core and CoP shell. As a result of synergy, Co3O4|CoP demonstrates an onset overpotential of 280 mV and reaches a current density of 10 mA cm–2 at an overpotential of 320 mV in an alkaline medium (pH = 13.5). The electronic property of the heterojunction is verified by the Tauc plot and valence band XPS. The band structure indicates that Co3O4|CoP exhibits a more metallic character than pristine Co3O4 due to the fact that …

Single-nucleotide polymorphism (SNP) markers have great potential to identify individuals, family relations, biogeographical ancestry, and phenotypic traits. In many forensic situations, DNA mixtures of a victim and an unknown suspect exist. Extracting SNP profiles from suspect’s samples can be used to assist investigation or gather intelligence. Computational tools to determine inclusion/exclusion of a known individual from a mixture exist, but no algorithm for extraction of an unknown SNP profile without a list of suspects is available. Here, we present an advanced haplotype-based HMM algorithm (AH-HA), a novel computational approach for extracting an unknown SNP profile from whole genome sequencing (WGS) of a two-person mixture. AH-HA utilizes techniques similar to the ones used in haplotype phasing. It constructs the inferred genotype as an imperfect mosaic of haplotypes from a reference panel of the target population. It outperforms more simplistic approaches, maintaining high performance through a wide range of sequencing depths (500×–5×). AH-HA can be applied in cases of victim–suspect mixtures and improves the capabilities of the investigating forces. This approach can be extended to more complex mixtures with more donors and less prior information, further motivating the development of SNP-based forensics technologies.

Carbon aerogels have been studied in the context of fuel cell electrodes mainly as catalyst support materials due to their high surface area, porosity, and electrical conductivity. Recently, aerogels composed solely of inorganic molecular complexes have shown to be promising materials for the electrocatalysis of oxygen reduction reaction (ORR). These aerogels consist of atomically dispersed catalytic sites. Herein, we report on the synthesis and characterization of an aerogel-based catalyst: iron phthalocyanine aerogel. It was synthesized by coupling of ethynyl-terminated phthalocyanine monomers and then heat-treated at 800 °C to increase its electrical conductivity and catalytic activity. The aerogels reported here were tested as catalysts for ORR in acidic conditions for the first time and found to have a ultra-high number of atomically dispersed catalytic sites (7.11 × 1020 sites g–1) and very good catalytic activity (E …

The rising interest in polymer electrolyte fuel cell (PEFC) technology, part of the global shift in energy production to clean sources, is accompanied by efforts to drive down the cost of this technology, which focus primarily on the cathode catalyst, the most expensive PEFC component. While platinum-group metals (PGMs) continues to be the materials of choice for oxygen reduction reaction (ORR) catalysts, use of these materials in PEFCs must be significantly reduced or eliminated without a penalty in the overall cell performance for PEFC technology to become fully viable.The most promising class ORR catalysts that do not utilize PGMs (i.e., PGM-free catalysts), involve first-row transition metals, such as iron and cobalt incorporated in a nitrogen-doped carbon (M-N-C catalysts). While advancements in M-N-C activity have been impressive, the much sought-after improvement in durability has been impeded by limited …

The two-dimensional electron system found between LaAlO3 and SrTiO3 hosts a variety of physical phenomena that can be tuned through external stimuli. This allows for electronic devices controlling magnetism, spin–orbit coupling, and superconductivity. Controlling the electron density by varying donor concentrations and using electrostatic gating are convenient handles to modify the electronic properties, but the impact on the microscopic scale, particularly of the former, remains underexplored. Here, we image the current distribution at 4.2 K in amorphous-LaAlO3/SrTiO3 using scanning superconducting quantum interference device microscopy while changing the carrier density in situ using electrostatic gating and oxygen annealing. We show how potential disorder affects the current and how homogeneous 2D flow evolves into several parallel conducting channels when approaching the metal-to-insulator …

Variation of grating amplitudes on a surface of amorphous chalcogenide films (ACF) As20Se80 has been studied under illumination by a band-gap light with the purpose to understand mechanism of photo-induced (PI) mass transfer. After holographic recording of surface relief gratings (SRGs) of various periods Λ (from 3 to 15 µm) they were illuminated by a diode laser (λ = 660 nm) and their profile variation was analyzed using optical microscopy, atomic force microscopy, light scattering, and optical profilometry. The SRGs with Λ < 8 µm exponentially flattened with time of illumination, whereas amplitudes of the SRGs with Λ > 8 µm exponentially grew. Theoretical analysis of the kinetics of PI mass transfer shows that the SRG profile variation occurs by bulk diffusion of As and Se atoms as a result of competition between capillary forces and electrostatic forces created by redistribution of electrons and holes generated …

Developing high performance, cost-effective, and durable electrocatalysts that must be derived from non-noble metals is crucial for alkaline oxygen evolution reaction (OER). OER, which takes place at the anode, is accepted as a major obstacle for commercialization due to its sluggish kinetics. In this study, a two-step synthesis method, such as a hydrothermal process followed by the annealing of the reactants in an Ar-filled Swagelok cell, is briefly described to obtain a cubic type of Co3O4 core and CoP shell. As a result of synergy, Co3O4 vertical bar CoP demonstrates an onset overpotential of 280 mV and reaches a current density of 10 mA cm(-2) at an overpotential of 320 mV in an alkaline medium (pH = 13.5). The electronic property of the heterojunction is verified by the Tauc plot and valence band XPS. The band structure indicates that Co3O4 vertical bar CoP exhibits a more metallic character than pristine …

Stress granules (SGs) can assemble in cancer cells upon chemotoxic stress. Glucocorticoids function during stress responses and are administered with chemotherapies. The roles of glucocorticoids in SG assembly and disassembly pathways are unknown. We examined whether combining glucocorticoids such as cortisone with chemotherapies from the vinca alkaloid family, which dismantle the microtubule network, affects SG assembly and disassembly pathways and influences cell viability in cancer cells and human-derived organoids. Cortisone augmented SG formation when combined with vinorelbine (VRB). Live-cell imaging showed that cortisone increased SG assembly rates but reduced SG clearance rates after stress, by increasing protein residence times within the SGs. Mechanistically, VRB and cortisone signaled through the integrated stress response mediated by eIF2α (also known as EIF2S1 …

Recent research points to mesenchymal stem cells’ potential for treating neurological disorders, especially drug addiction. We examined the longitudinal effect of placenta-derived mesenchymal stromal-like cells (PLX-PAD) in a rat model for cocaine addiction. Sprague–Dawley male rats were trained to self-administer cocaine or saline daily until stable maintenance. Before the extinction phase, PLX-PAD cells were administered by intracerebroventricular or intranasal routes. Neurogenesis was evaluated, as was behavioral monitoring for craving. We labeled the PLX-PAD cells with gold nanoparticles and followed their longitudinal migration in the brain parallel to their infiltration of essential peripheral organs both by micro-CT and by inductively coupled plasma-optical emission spectrometry. Cell locations in the brain were confirmed by immunohistochemistry. We found that PLX-PAD cells attenuated cocaine-seeking behavior through their capacity to migrate to specific mesolimbic regions, homed on the parenchyma in the dentate gyrus of the hippocampus, and restored neurogenesis. We believe that intranasal cell therapy is a safe and effective approach to treating addiction and may offer a novel and efficient approach to rehabilitation.

Fuel cells are already employed in commercial transportation even though their price is still too high to enable widespread production. A viable and promising pathway taken to lower this price is the replacement of expensive constitutes, namely the platinum-based catalysts at the cathode, by platinum group metal-free catalysts based on abundant materials, such as iron. This led to the development of iron-based catalysts that show high activity towards the oxygen reduction reaction. The extraction of the intrinsic catalytic activity of any catalyst is important both for finding relations between the chemical properties of the active sites and their activity, as well as a comparison measure between catalysts. An important parameter that has been elusive for many years is the turnover frequency, which is derived form the number of electrochemical active sites’ density (EASD). The ability to measure the EASD was very limited …

Performance, durability, and abundance/cost of electrocatalytic materials are fundamental parameters in for large electrochemical storage solutions like redox-flow batteries (RFB). The acidic environment in Hydrogen–Bromine RFB (HBRFB), which targets tens of thousands of hours in durability, makes the challenge even more acute. Continuous effort to find the most effective and stable catalyst can promote HBRFB goal to become sustainable for high power storage systems. Herein, we explore the lower limits in catalyst loading for the two most active precious group metals (PGMs) – platinum and iridium (individually and in a bimetallic catalyst). The catalyst has been structurally characterized and lab-scale redox-flow cells have been cycled with a decreasing loading of PGM. Carbon support and polymeric coating on Pt catalyst shows a significant increase in the utilization of the catalyst. It enables low platinum …

Developing high performance, cost-effective, and durable electrocatalysts that must be derived from non-noble metals is crucial for alkaline oxygen evolution reaction (OER). OER, which takes place at the anode, is accepted as a major obstacle for commercialization due to its sluggish kinetics. In this study, a two-step synthesis method, such as a hydrothermal process followed by the annealing of the reactants in an Ar-filled Swagelok cell, is briefly described to obtain a cubic type of Co3O4 core and CoP shell. As a result of synergy, Co3O4|CoP demonstrates an onset overpotential of 280 mV and reaches a current density of 10 mA cm–2 at an overpotential of 320 mV in an alkaline medium (pH = 13.5). The electronic property of the heterojunction is verified by the Tauc plot and valence band XPS. The band structure indicates that Co3O4|CoP exhibits a more metallic character than pristine Co3O4 due to the fact that …

Nuclear speckles are dynamic membraneless bodies located in the cell nucleus. They harbor RNAs and proteins, many of which are splicing factors, that together display complex biophysical properties dictating nuclear speckle formation and maintenance. Although these nuclear bodies were discovered decades ago, only recently has in-depth genomic analysis begun to unravel their essential functions in modulation of gene activity. Major advancements in genomic mapping techniques combined with microscopy approaches have enabled insights into the roles nuclear speckles may play in enhancing gene expression, and how gene positioning to specific nuclear landmarks can regulate gene expression and RNA processing. Some studies have drawn a link between nuclear speckles and disease. Certain maladies either involve nuclear speckles directly or dictate the localization and reorganization of many nuclear speckle factors. This is most striking during viral infection, as viruses alter the entire nuclear architecture and highjack host machinery. As discussed in this Review, nuclear speckles represent a fascinating target of study not only to reveal the links between gene positioning, genome subcompartments and gene activity, but also as a potential target for therapeutics.

Doped Mott insulators exhibit some of the most intriguing quantum phases of matter, including quantum spin liquids, unconventional superconductors and non-Fermi liquid metals–. Such phases often arise when itinerant electrons are close to a Mott insulating state, and thus experience strong spatial correlations. Proximity between different layers of van der Waals heterostructures naturally realizes a platform for experimentally studying the relationship between localized, correlated electrons and itinerant electrons. Here we explore this relationship by studying the magnetic landscape of tantalum disulfide 4Hb-TaS2, which realizes an alternating stacking of a candidate spin liquid and a superconductor. We report on a spontaneous vortex phase whose vortex density can be trained in the normal state. We show that time-reversal symmetry is broken in the normal state, indicating the presence of a magnetic phase …

Single-nucleotide polymorphism (SNP) markers have great potential to identify individuals, family relations, biogeographical ancestry, and phenotypic traits. In many forensic situations, DNA mixtures of a victim and an unknown suspect exist. Extracting SNP profiles from suspect’s samples can be used to assist investigation or gather intelligence. Computational tools to determine inclusion/exclusion of a known individual from a mixture exist, but no algorithm for extraction of an unknown SNP profile without a list of suspects is available. Here, we present an advanced haplotype-based HMM algorithm (AH-HA), a novel computational approach for extracting an unknown SNP profile from whole genome sequencing (WGS) of a two-person mixture. AH-HA utilizes techniques similar to the ones used in haplotype phasing. It constructs the inferred genotype as an imperfect mosaic of haplotypes from a reference panel of the target population. It outperforms more simplistic approaches, maintaining high performance through a wide range of sequencing depths (500×–5×). AH-HA can be applied in cases of victim–suspect mixtures and improves the capabilities of the investigating forces. This approach can be extended to more complex mixtures with more donors and less prior information, further motivating the development of SNP-based forensics technologies.

One of the most challenging tasks in analytical chemistry is the determination of the chirality (identi cation of an enantio-meric composition) in solids mainly because of the strict requirements of the pharmaceutical industry for enantiomerically pure drugs. Although there are a few methods available to accomplish enantio-differentiation in solids, for example: X-ray diffraction (XRD), differential scanning calorimetry (DSC), CD spectroscopy, and low-frequency (LF) Raman spectroscopy, this is still very challenging. In this work, we have developed a new method to measure the chirality of crystals, based on electron paramagnetic resonance (EPR) spectroscopy of chiral crystals doped with Cu2+ as the EPR active ion. Here, we demonstrate our approach using a model system of L-and DL-Histidine crystals doped with Cu2+. We show that EPR measurements of the Cu2+-doped Histidine crystals can accurately determine the chirality and enantiomeric composition of the crystals. We present a very preliminary example of this technique, and we hope that in the future it will be possible to re ne and develop this method for many other chiral organic crystal systems.

The physiological acrosome reaction occurs after mammalian spermatozoa undergo a process called capacitation in the female reproductive tract. Only acrosome reacted spermatozoon can penetrate the egg zona-pellucida and fertilize the egg. Sperm also contain several mechanisms that protect it from undergoing spontaneous acrosome reaction (sAR), a process that can occur in sperm before reaching proximity to the egg and that abrogates fertilization. We previously showed that calmodulin-kinase II (CaMKII) and phospholipase D (PLD) are involved in preventing sAR through two distinct pathways that enhance F-actin formation during capacitation. Here, we describe a novel additional pathway involving the tyrosine kinase Fer in a mechanism that also prevents sAR by enhancing actin polymerization during sperm capacitation. We further show that protein-kinase A (PKA) and the tyrosine-kinase Src, as well as …