BINA

Nuclear forward scattering (NFS) is a synchrotron-based technique relying on the recoil-free nuclear resonance effect similar to Mössbauer spectroscopy. In this work, we introduce NFS for in situ and operando measurements during electrocatalytic reactions. The technique enables faster data acquisition and better discrimination of certain iron sites in comparison to Mössbauer spectroscopy. It is directly accessible at various synchrotrons to a broad community of researchers and applicable to multiple metal isotopes. We demonstrate the power of this technique with the hydrogen evolution mechanism of an immobilized iron porphyrin supported on carbon. Such catalysts are often considered as model systems for iron-nitrogen-carbon (FeNC) catalysts. Using in situ and operando NFS in combination with theoretical predictions of spectroscopic data enables the identification of the intermediate that is formed prior to the rate determining step. The conclusions on the reaction mechanism can be used for future optimization of immobilized molecular catalysts and metal-nitrogen-carbon (MNC) catalysts.

In-cell electron paramagnetic resonance (EPR) spectroscopy experiments provide high-resolution data about conformational changes of proteins within the cell. However, one of the limitations of EPR is the requisite of stable paramagnetic centers in a reducing environment. We recently showed that histidine-rich sites in proteins hold a high affinity to Cu(II) ions complexed with a chelator. Using a chelator prevents the reduction of Cu(II) ions. Moreover, this spin-labeling methodology can be performed within the native cellular environment on any overexpressed protein without protein purification and delivery to the cell. Herein, we use this novel methodology to gain spatial information on the extracellular domain of the human copper transporter, hCtr1. Limited structural information on the transmembrane domain of the human Ctr1 (hCtr1) was obtained using X-ray crystallography and cryo-EM. However, these …

The performance of lithium–sulfur (Li–S) rechargeable batteries is strongly dependent on the entrapment of the higher‐order intermediate polysulfides at the sulfur cathode. An attracting way of preventing the polysulfide shuttle is by introducing a polar host which can form a Lewis acid–base complex with polysulfides. Herein, the Li–S battery by incorporating iron sulfides (FeS2) as a polar Lewis acid to entrap higher‐order polysulfides at the cathode center is investigated. FeS2/S cathode demonstrates largely improved retention of capacity compared to C/S cathode (capacity fading per cycle of 0.12% and 0.80% for FeS2/S and C/S respectively) and good rate performance in Li–S batteries compared to conventional carbon–sulfur (C/S) cathode. This is attributed to the decrease in polysulfide dissolution and better retention of active sulfur in the cathode during battery cycling which is due to the polar FeS2 additive …

Silica (SiO2) particles are widely used in various industries due to their chemical inertness, thermal stability, and wear resistance. The present study describes the preparation and potential use of porous hydrophobic and hydrophilic SiO2 microcapsules (MCs) of a narrow size distribution. First, various layers of SiO2 micro/nano-particles (M/NPs) were grafted onto monodispersed polystyrene (PS) microspheres of a narrow size distribution. Hydrophobic and hydrophilic sintered SiO2 MCs were then prepared by removing the core PS from the PS/SiO2 core–shell microspheres by burning off under normal atmospheric conditions or organic solvent dissolution, respectively. We examined how the size and quantity of the SiO2 M/NPs influence the MC’s properties. Additionally, we utilized two forms of hollow SiO2 MC for different applications; one form was incorporated into polymer films, and the other was free-floating …

Quantum query complexity mainly studies the number of queries needed to learn some property of a black box with high probability. A closely related question is how well an algorithm can succeed with this learning task using only a fixed number of queries. In this work, we propose measuring an algorithm's performance using the mutual information between the output and the actual value. A key observation is that if an algorithm is only allowed to make a single query and the goal is to optimize this mutual information, then we obtain a task which is similar to a basic task of quantum communication, where one attempts to maximize the mutual information of the sender and receiver. We make this analogy precise by formally considering the oracle as a separate subsystem, whose state records the unknown oracle identity. The oracle query prepares a state, which is then measured; and the target property of the oracle plays the role of a message that should be deduced from the measurement outcome. Thus we obtain a link between the optimal single-query algorithm and minimization of the extent of quantum correlations between the oracle and the computer subsystems. We also find a lower bound on this mutual information, which is related to quantum coherence. These results extend to multiple-query non-adaptive algorithms. As a result, we gain insight into the task of finding the optimal non-adaptive algorithm that uses at most a fixed number of queries, for any oracle problem.

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a cancer-causing virus that establishes life-long infection. KSHV is implicated in the etiology of Kaposi’s sarcoma, and a number of rare hematopoietic malignancies. The present study focuses on the KSHV open reading frame 20 (ORF20), a member of the conserved herpesvirus UL24 protein family containing five conserved homology domains and a conserved PD-(D/E)XK putative endonuclease motif, whose nuclease function has not been established to date. ORF20 encodes three co-linear protein isoforms, full length, intermediate, and short, though their differential functions are unknown. In an effort to determine the role of ORF20 during KSHV infection, we generated a recombinant ORF20-Null KSHV genome, which fails to express all three ORF20 isoforms. This genome was reconstituted in iSLK cells to establish a latent infection, which resulted in an accelerated transcription of viral mRNAs, an earlier accumulation of viral lytic proteins, an increase in the quantity of viral DNA copies, and a significant decrease in viral yield upon lytic reactivation. This was accompanied by early cell death of cells infected with the ORF20-Null virus. Functional complementation of the ORF20-Null mutant with the short ORF20 isoform rescued KSHV production, whereas its endonuclease mutant form failed to enhance lytic reactivation. Complementation with the short isoform further revealed a decrease in cell death as compared with ORF20-Null virus. Finally, expression of IL6 and CXCL8, previously shown to be affected by the hCMV UL24 homolog, was relatively low upon reactivation of cells infected with …

This study explores the effect of doping density on the performance of split-well resonant-phonon (SWRP) Terahertz Quantum Cascade Lasers (THz QCLs) through non-equilibrium Green’s functions (NEGF) analysis. Experimental research showed that increasing the doping concentration in these designs led to better results compared to the split-well direct-phonon (SWDP) design, which has a larger overlap between its active laser states and the doping profile. We also found that electron-electron (e-e) scattering is a major factor in performance limitation. By identifying key scattering mechanisms, we propose optimization strategies for doping profiles and material quality to enhance operational temperatures. This research offers insights into overcoming current limitations in THz QCLs, setting a foundation for future technological advancements.

In this research we investigate the issues that arise from line broadening in m-plane GaN Terahertz Quantum Cascade Lasers (THz QCLs). Our study using non-equilibrium Green’s functions (NEGF) shows that factors beyond longitudinal-optical (LO) phonon coupling contribute to line broadening. Despite these challenges, increased doping densities were found to increase gain, allowing for lasing at up to 280 K at 7.2 THz. This indicates the potential of practical GaN-based THz QCLs for high-temperature applications, suggesting avenues for achieving room temperature operation and advancing THz QCL development.

Despite their importance, there is an ongoing challenge characterizing multipartite quantum correlations. The Seevinck-Svetlichny (SS) and Mermin-Klyshko (MK) inequalities present constraints on correlations in multipartite systems, a violation of which allows to classify the correlations by using the nonseparability property. In this work we present refined Tsirelson (quantum) bounds on these inequalities, derived from inequalities stemming from a fundamental constraint, tightly akin to quantum uncertainty. Unlike the original, known inequalities, our bounds do not consist of a single constant point but rather depend on correlations in specific subsystems (being local correlations for our bounds on the SS operators and bipartite correlations for our bounds on the MK operators). We analyze concrete examples in which our bounds are strictly tighter than the known bounds, i.e., lie beneath the previously found constants …

Quantum tunneling (QT) is not an effect often considered in chemistry, and rightfully so. However, in many cases it is significant, and in some cases it is even considerable. In this chapter we will describe the basic tenets of QT with a focus on catalysis, followed by some of the most important tools to study and compute them. The chapter goes on to address the title of the chapter by discussing several clear cases of QT for hydrogen-based reactions in organometallic, enzymatic, astrochemical, and organic systems. The insights highlighted in the chapter showcase the importance of QT in specific catalyzed reactions and help uncover the instances that are worth of attention.

This research compares two two-well (TW) Terahertz Quantum Cascade Lasers (THz QCLs) using non-equilibrium Green’s functions (NEGF) in order to understand the discrepancy in their maximum operating temperatures (T max ). Despite similar designs and simulation findings, the devices show a substantial performance difference. This is connected to variations in interface roughness (IFR) caused by different Molecular Beam Epitaxy (MBE) reactors. Our findings highlight the necessity of accurate MBE growth control for high-performance THz QCLs and propose approaches for interface modification to improve device temperature performance, providing a clearer path to meeting and exceeding current T max records.

Modulation of electronic properties of materials by electric fields is central to the operation of modern semiconductor devices, providing access to complex electronic behaviors and greater freedom in tuning the energy bands of materials. Here, we explore one-dimensional superlattices induced by a confining electrostatic potential in monolayer MoS, a prototypical two-dimensional semiconductor. Using first-principles calculations, we show that periodic potentials applied to monolayer MoS induce electrostatic superlattices in which the response is dominated by structural distortions relative to purely electronic effects. These structural distortions reduce the intrinsic band gap of the monolayer substantially while also polarizing the monolayer through piezoelectric coupling, resulting in spatial separation of charge carriers as well as Stark shifts that produce dispersive minibands. Importantly, these minibands inherit the valley-selective magnetic properties of monolayer MoS, enabling fine control over spin-valley coupling in MoS and similar transition-metal dichalcogenides.

The ramp reversal memory (RRM) is a non-volatile memory effect previously observed in correlated oxides exhibiting temperature-driven metal-insulator transitions (MITs). In essence, when a system displaying RRM is heated to a specific temperature within the MIT regime - where metallic and insulating domains coexist - and then cooled by reversing the temperature ramp, the resistance increases in the subsequent heating cycle. Crucially, this increase occurs only in the vicinity of the reversal temperature, indicating that the system 'remembers' this temperature. However, this memory is erased in the next heating loop. While such an effect could potentially manifest in various systems, to date, it has only been reported in thin films of correlated transition metal oxides, including VO2, V2O3, and NdNiO3. In this work, we report the observation of RRM in macroscopic crystals of the layered material 1T-TaS2, which undergoes an MIT near 190 K along charge-density wave transitions. Our findings provide compelling evidence that RRM is a general phenomenon, extending beyond the previously studied oxides. Interestingly, the RRM in TaS2 displays significantly different characteristics: it is observed when reversing from cooling to heating (as opposed to heating to cooling), and its magnitude - representing the 'strength' of the memory - is nearly an order of magnitude larger than in correlated oxides. While we discuss potential mechanisms for the RRM in TaS2, a comprehensive first-principles model is still lacking. We hope that this study will prompt further investigation into the underlying mechanisms of ramp reversal memory, enhancing our …

Analyzing complex experimental data with multiple parameters is challenging. We propose using Singular Value Decomposition (SVD) as an effective solution. This method, demonstrated through real experimental data analysis, surpasses conventional approaches in understanding complex physics data. Singular values and vectors distinguish and highlight various physical mechanisms and scales, revealing previously challenging elements. SVD emerges as a powerful tool for navigating complex experimental landscapes, showing promise for diverse experimental measurements.

A-to-I RNA editing is a cellular mechanism that generates transcriptomic and proteomic diversity, which is essential for neuronal and immune functions. It involves the conversion of specific adenosines in RNA molecules to inosines, which are recognized as guanosines by cellular machinery. Despite the vast number of editing sites observed across the animal kingdom, pinpointing critical sites and understanding their in vivo functions remains challenging. Here, we study the function of an evolutionary conserved editing site in Drosophila, located in glutamate-gated chloride channel (GluClα). Our findings reveal that flies lacking editing at this site exhibit reduced olfactory responses to odors and impaired pheromone-dependent social interactions. Moreover, we demonstrate that editing of this site is crucial for the proper processing of olfactory information in projection neurons. Our results highlight the value of using …

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a cancer-causing virus that establishes life-long infection. KSHV is implicated in the etiology of Kaposi’s sarcoma, and a number of rare hematopoietic malignancies. The present study focuses on the KSHV open reading frame 20 (ORF20), a member of the conserved herpesvirus UL24 protein family containing five conserved homology domains and a conserved PD-(D/E)XK putative endonuclease motif, whose nuclease function has not been established to date. ORF20 encodes three co-linear protein isoforms, full length, intermediate, and short, though their differential functions are unknown. In an effort to determine the role of ORF20 during KSHV infection, we generated a recombinant ORF20-Null KSHV genome, which fails to express all three ORF20 isoforms. This genome was reconstituted in iSLK cells to establish a latent infection, which resulted in an accelerated transcription of viral mRNAs, an earlier accumulation of viral lytic proteins, an increase in the quantity of viral DNA copies, and a significant decrease in viral yield upon lytic reactivation. This was accompanied by early cell death of cells infected with the ORF20-Null virus. Functional complementation of the ORF20-Null mutant with the short ORF20 isoform rescued KSHV production, whereas its endonuclease mutant form failed to enhance lytic reactivation. Complementation with the short isoform further revealed a decrease in cell death as compared with ORF20-Null virus. Finally, expression of IL6 and CXCL8, previously shown to be affected by the hCMV UL24 homolog, was relatively low upon reactivation of cells infected with …

The noninvasive measurement and sensing of vital bio signs, such as respiration and cardiopulmonary parameters, has become an essential part of the evaluation of a patient’s physiological condition. The demand for new technologies that facilitate remote and noninvasive techniques for such measurements continues to grow. While previous research has made strides in the continuous monitoring of vital bio signs using lasers, this paper introduces a novel technique for remote noncontact measurements based on radio frequencies. Unlike laser-based methods, this innovative approach offers the advantage of penetrating through walls and tissues, enabling the measurement of respiration and heart rate. Our method, diverging from traditional radar systems, introduces a unique sensing concept that enables the detection of micro-movements in all directions, including those parallel to the antenna surface. The main goal of this work is to present a novel, simple, and cost-effective measurement tool capable of indicating changes in a subject’s condition. By leveraging the unique properties of radio frequencies, this technique allows for the noninvasive monitoring of vital bio signs without the need for physical contact or invasive procedures. Moreover, the ability to penetrate barriers such as walls and tissues opens new possibilities for remote monitoring in various settings, including home healthcare, hospital environments, and even search and rescue operations. In order to validate the effectiveness of this technique, a series of experiments were conducted using a prototype device. The results demonstrated the feasibility of accurately measuring …

Hard x-ray imaging is indispensable across diverse fields owing to its high penetrability. However, the resolution of traditional x-ray imaging modalities, such as computed tomography (CT) systems, is constrained by factors including beam properties, the limitations of optical components, and detection resolution. As a result, the typical resolution in commercial imaging systems that provide full-field imaging is limited to a few hundred microns, and scanning CT systems are too slow for many applications. This study advances high-photon-energy imaging by extending the concept of computational ghost imaging to multipixel ghost imaging with x-rays. We demonstrate a remarkable resolution of approximately 20 µm for an image spanning 0.9 by 1 cm^2, comprised of 400,000 pixels and involving only 1000 realizations. Furthermore, we present a high-resolution CT reconstruction using our method, revealing …

There is agreement that every colloidal structure produces its own set of unique characteristics, properties, and applications. A colloidal phenomenon of latex-bridged water in a dimethyl carbonate (DMC) Pickering emulsion stabilized by R202 hydrophobic silica was investigated for its ability to act as a superhydrophobic coating (SHC) for cellulose substrates. First, various emulsion compositions were screened for their stability and droplet size. The final composition was then cross-examined by cryogenic scanning electron microscopy and optical and fluorescent microscopy to verify the colloidal structure. The drying pattern of the coating was investigated by using labeled samples under a fluorescent microscope and by scanning electron microscopy on a paper substrate. After the final ∼3 μm of dry coating was applied, it exhibited superhydrophobicity (advancing contact angle = 155°) and full functionality after 5 …