bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anderson localization and the integer quantum Hall transition: a new perspective
Authors: Kettemann S. , Tsvelik A. 
Published: April 2022

AbstractThe autocorrelation function of spectral determinants (ASD) is used to probe a system of disordered electrons. It is represented as an effective partition function, and thus the problem is reduced to finding the spectrum of the respective effective Hamiltonian. A spectral gap above its ground state is argued to be a strong indication that all states are localized. This method is demonstrated for electrons in a quasi‐ 1– dimensional disordered metal wire as a function of a magnetic field, and for two‐dimensional disordered electrons in weak and strong magnetic fields.
Review of recent progress on numerical studies of the Anderson transition
Authors: Ohtsuki Tomi , Slevin Keith , Kawarabayashi Tohru 
Published: April 2022

AbstractA review of recent progress in numerical studies of the Anderson transition in three dimensional systems is presented. From high precision calculations the critical exponentνfor the divergence of the localization length is estimated to beν= 1.57 ± 0.02 for the orthogonal universality class, which is clearly distinguished fromν= 1.43 ± 0.03 for the unitary universality class. The boundary condition dependences of some quantities at the Anderson transition are also discussed.
Exact eigenstates and transmission for two interacting electrons on quantum dots
Authors: Aharony A. , Entin‐Wohlman O. , Levinson Y. , Imry Y. 
Published: April 2022

AbstractThe eigenstates and the scattering transmission for two interacting electrons are found exactly for I quantum dots, including the hybridization with the states on the leads. The results imply limitations on the validity of the Coulomb blockade picture. The ground states for I = 1, 2 on a one–dimensional chain (modeling single and double quantum dots) exhibit quantum delocalization and magnetic transitions. The effective transmission T of two interacting electrons through one impurity (I = 1) is enhanced by a renormalization of the repulsive interaction, when one of the electrons is captured in a strongly localized state.
Critical Hamiltonians with long range hopping
Authors: Levitov L.S. 
Published: April 2022

AbstractCritical states are studied by a real space RG in the problem with strong diagonal disorder and long range power law hopping. The RG ow of the distribution of coupling parameters is characterized by a family of non‐trivial fix points. We consider the RG flow of the distribution of participation ratios of eigenstates. Scaling of participation ratios is sensitive to the nature of the RG fix point. For some fix points, scaling of participation ratios is characterized by a distribution of exponents, rather than by a single exponent.The RG method can be generalized to treat certain fermionic Hamiltonians with disorder and long range hopping. We derive the RG for a model of interacting two‐level systems. Besides couplings, in this problem the RG includes the density of states. The density of states is renormalized so that it develops a singularity near zero energy.
Horizon problem in a closed universe dominated by fluid with negative pressure
Authors: Stelmach Jerzy 
Published: April 2022

AbstractWe discuss the horizon problem in a universe dominated by fluid with negative pressure. We show that for generally accepted value of nonrelativistic matter energy density parameter Ωm0 < 1, the horizon problem can be solved only if the fluid influencing negative pressure (the so‐called “X” component) violates the point‐wise strong energy condition and if its energy density is sufficiently large (ΩX0 > 1). The calculated value of the ΩX0 parameter allowing for the solution of the horizon problem is confronted with some recent observational data. Assuming that pX/ρX < —0.6 we find that the required amount of the “X” component is not ruled out by the supernova limits. Since the value of energy density parameter Ωv0 for cosmological constant larger than 1 is excluded by gravitational lensing observations the value of the ratio pX/ρX should lie between the values —1 and —0.6 if the model has to be free of the horizon problem beeing at the same time consistent with observations. The value of ΩX0 + Ωm0 in the model is consistent with the constraints 0.2 < Ωtot < 1.5 following from cosmic microwave background observations provided that Ωm0 is low (<0.2).
The Limited Palette for Photonic Block‐Copolymer Materials: A Historical Problem or a Practical Limitation?
Authors: Wang Zhen , Chan Chun Lam Clement , Parker Richard M. , Vignolini Silvia 
Published: April 2022

AbstractBlock‐copolymer self‐assembly has proven to be an effective route for the fabrication of photonic films and, more recently, photonic pigments. However, despite extensive research on this topic over the past two decades, the palette of monomers and polymers employed to produce such structurally colored materials has remained surprisingly limited. In this Scientific Perspective, the commonly used block‐copolymer systems reported in the literature are summarized (considering both linear and brush architectures) and their use is rationalized from the point of view of both their historical development and physicochemical constraints. Finally, the current challenges facing the field are discussed and promising new areas of research are highlighted to inspire the community to pursue new directions.
Photosensitized [2+2]‐Cycloadditions of Alkenylboronates and Alkenes
Authors: Liu Yanyao , Ni Dongshun , Stevenson Bernard G. , Tripathy Vikrant , Braley Sarah E. , Raghavachari Krishnan , Swierk John R. , Brown M. Kevin 
Published: April 2022

AbstractA new strategy for the synthesis of highly versatile cyclobutylboronates via the photosensitized [2+2]‐cycloaddition of alkenylboronates and alkenes is presented. The process is mechanistically different from other processes in that energy transfer occurs with the alkenylboronate as opposed to the other alkene. This strategy allows for the synthesis of an array of diverse cyclobutylboronates. The conversion of these adducts to other compounds as well as their utility in the synthesis of melicodenine C is demonstrated.
Toward Label‐Free Optical Multiplexing of Analytes in Indicator Release Lateral Flow Assays via Detection Zones Containing Tailored Capture Materials
Authors: Climent Estela , Wan Wei , Rurack Knut 
Published: April 2022

AbstractThe use of macromolecules and materials immobilized in the detection zone of test strips for indicator capture and focusing in label‐free lateral flow assays (LFAs) is described, with emphasis on its future use in low number multiplexing. Several materials such as polyelectrolytes, functionalized mesoporous silica micro‐ and nanoparticles, chemically modified cellulose or glass fibre (GF) membranes and molecularly imprinted polymer gels coated onto membranes were studied in model assays, before the most promising materials were combined with antibody‐gated indicator delivering (gAID) sensor materials. Cellulose, nitrocellulose and GF membranes were used as supports and highly fluorescent dyes of different charge states as model indicators. Combination of the best performing capture materials with gAID systems made it possible to distinctly increase the sensitivity and reduce the measurement uncertainty in the LFA testing of pentaerythritol tetranitrate (PETN) in aqueous samples. In addition, dual‐plexing of PETN and 2,4,6‐trinitrotoluene (TNT) was realized on a single test strip containing two dedicated capture zones.
Graft polymerization of methyl methacrylate on the surface of poly(ethylene‐co‐tetrafluoroethylene) using benzoyl peroxide as initiator
Authors: Mizuta Yusuke , Sugimoto Ryuichi , Okada Hiromu , Zhao Chao , Kobiro Kazuya , Nishiwaki Nagatoshi 
Published: April 2022

AbstractThe surface of a poly(ethylene‐co‐tetrafluoroethylene) (ETFE) film was modified by benzoyl peroxide (BPO)‐initiated graft polymerization of methyl methacrylate (MMA). After graft polymerization, the appearance of the ETFE film changed considerably, and the Fourier transform infrared (FT‐IR) spectra showed absorption peaks attributed to carbonyl functionalities. The efficiency of graft polymerization was strongly influenced by several factors such as the reaction temperature, reaction time, and concentration of BPO. The highest graft yield (69%) was obtained at 0.1 mol% BPO concentration and at a reaction temperature of 75°C for 24 h. The properties of the ETFE film surface were altered by the graft polymerization of MMA, which facilitated dyeing of the surface.
Development of ionic liquid plasticized high‐tensile starch‐protein‐sorghum bran composite films with antimicrobial activity
Authors: Tyagi Varee , Wang Yixiang , Bhattacharya Bhaswati 
Published: April 2022

AbstractIonic liquid (1‐butyl‐3‐methyl imidazolium chloride—[bmim]Cl) was used as a plasticizer alternative to enhance the mechanical strength of the starch‐zein composite films. Additionally, sorghum bran extract (SBE) was utilized as a sustainable source of bioactive compounds to introduce the antimicrobial activity to the composite films. [Bmim]Cl provided better solubilization capacity thereby enhancing the compatibility of film components. Thus, [bmim]Cl substantially improved the tensile strength and elongation at break of the ionic liquid plasticized (8.93 ± 1.59 MPa and 29.53 ± 0.86%) as well as sorghum bran functionalized films (8.99 ± 0.42 MPa and 21.91 ± 0.76%). Incorporation of SBE to the potato starch‐zein film solution enhanced opacity and attributed antioxidant properties to the composite film and that endorsed the possibility of inhibiting lipid peroxidation. Furthermore, the sorghum bran functionalized films possessed antimicrobial activity against Escherichia coli, making them appropriate for active packaging applications.
Structure–property relationships and constitutive viscoelastic behaviors of polyether‐block‐amide elastomers in melt and solid states
Authors: Ercan Nevra , Durmus Ali 
Published: April 2022

AbstractIn this study, effects of copolymer composition on the structural, thermal, and viscoelastic properties of segmented multi‐block polyamide elastomers (PEBAX® 3533, 5533, and 6333) and polyamide‐12 (PA12) were quantified by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, and dynamic mechanical analysis (DMA) methods and rheological measurements. Soft segment, poly(tetramethylene oxide) (PTMO), contents of copolymers were proved by FTIR analysis. It was found that the increase in PTMO content dramatically reduced the crystallization and melting temperatures and degree of crystallinity values of copolymers. Different rheological test protocols performed in melt state revealed that zero shear rate viscosity values of polyamide elastomers increased with the increasing amount of hard segment. On the other hand, increase in hard segment content yielded lower flow activation energy value. In this study, we mainly focused on understanding quantitative relationships between block copolymer structure and their rheological behaviors and found that the soft segment content of ~40 (mole %) is the critical point for changing the rheological behaviors of block copolymer PAEs, dramatically. DMA measurements implied that the solid‐state viscoelastic behaviors of samples were governed by the hard content of copolymers. Higher hard content decreased long‐term creep strain and creep rate.
Monoamine‐modified thin film composite nanofiltration membrane for permselective separation of fermentation bioproducts
Authors: Gonzales Ralph Rolly , Shintani Takuji , Sunami Shunsuke , Sasaki Yuji , Nakagawa Keizo , Yoshioka Tomohisa , Matsuyama Hideto 
Published: April 2022

AbstractOne process involved in biorefinery for generation of value‐added products is fermentation. After fermentation, the downstream bioproduct purification process is conventionally performed by organic solvent extraction, which is environmentally‐hazardous and costly. Membrane‐based separation is a cost‐efficient and environmentally‐benign method for bioproduct separation and purification. In this study, a thin film composite (TFC) nanofiltration (NF) membrane was prepared and the pore size and charge of the polyamide layer were controlled by introducing iminodiacetic acid (IDA), a charged monoamine monomer, with piperazine (PIP) during interfacial polymerization (IP). The newly‐developed NF membrane was found to have a molecular weight cut‐off (MWCO) of 500 to 1350 Da, allowing the permeation of the fermentation product, while rejecting other higher molecular weight compounds. IDA addition in the aqueous amine solution during IP effectively engineered the MWCO values and pore sizes of TFC NF membranes for specific applications, such as separation of fermentation bioproducts. This study successfully showed that IDA reduced the diffusivity of PIP during IP, which negatively affected the polyamide formation and membrane performance. The optimal PIP:IDA concentration ratio was determined by MWCO and effective pore diameter for effective bioproduct separation and purification, which could not be performed by the current commercially‐available NF membranes.
A comprehensive review of recent advances in the biological activities of 1,2,4‐oxadiazoles
Authors: Hendawy Omnia M. 
Published: April 2022

AbstractNitrogen heterocycles play an essential role in medication development. The 1,2,4‐oxadiazole heterocycle has been extensively studied, yielding a large variety of molecules with varied biological functions. The 1,2,4‐oxadiazole shows bioisosteric equivalency with ester and amide moieties. In recent years, the 1,2,4‐oxadiazole nucleus has received a lot of attention in medicinal chemistry. It was thought to be a pharmacophore component in the production of biologically intriguing drugs. This review presents a comprehensive overview of the recent achievements in the biological activities of 1,2,4‐oxadiazoles as potential antimicrobial, anticancer, anti‐inflammatory, neuroprotective, and antidiabetic agents. The structure–activity relationship and mechanisms of action are also reviewed.
C2‐Symmetric Bissulfoximine‐Based Metal Complexes: Synthesis, Characterization and Their Electrocatalytic Activity in Oxygen Reduction Reaction
Authors: Junaid Qazi Mohammad , Kumar Singh Devesh , Ganesan Vellaichamy , Sabiah Shahulhameed 
Published: April 2022

AbstractSulfoximine‐based metal complexes have gained much interest in recent years owing to their promising properties in synthetic organic chemistry. These sulfoximines have been recently introduced in the field of organometallics. However, the coordination properties of pincer sulfoximine ligands and their metal complexes have not been reported. Here, a C2‐symmetric bissulfoximine‐based pincer ligand ((pyridine‐2,6‐diylbis(methylene))bis(azaneylylidene))bis(diphenyl‐λ6‐sulfanone), namely S‐P ligand and its metal [M(SP)2]2+ {M=Fe (SC‐1), Co (SC‐2), Ni (SC‐3), Cu (SC‐4)} complexes, were synthesized. The complexes were characterized by different spectroscopic techniques like UV‐Vis, IR, NMR, ESI‐MS, and single‐crystal XRD. Complexes SC‐1 and SC‐3 exhibited octahedral geometry irrespective of the metal center. The complexes were systematically explored for electrocatalytic oxygen reduction reaction (ORR) by immobilizing them on a glassy carbon electrode using Nafion. These complexes showed selective two‐electron catalytic reduction of O2 to H2O2 in which complex SC‐2 showed the highest selectivity (≈90%) and complex SC‐4 showed the highest onset potential (0.75 V).
Single‐Molecule Classification of Aspartic Acid and Leucine by Molecular Recognition through Hydrogen Bonding and Time‐Series Analysis
Authors: Ryu Jiho , Komoto Yuki , Ohshiro Takahito , Taniguchi Masateru 
Published: April 2022

AbstractAmino acid detection/identification methods are important for understanding biological systems. In this study, we developed single‐molecule measurements for investigating quantum tunneling enhancement by chemical modification and carried out machine learning‐based time series analysis for developing accurate amino acid discrimination. We performed single‐molecule measurement of L‐aspartic acid (Asp) and L‐leucine (Leu) with a mercaptoacetic acid (MAA) chemical modified nano‐gap. The measured current was investigated by a machine learning‐based time series analysis method for accurate amino acid discrimination. Compared to measurements using a bare nano‐gap, it is found that MAA modification improves the difference in the conductance‐time profiles between Asp and Leu through the hydrogen bonding facilitated tunneling phenomena. It is also found that this method enables determination of relative concentration. even in the mixture of Asp and Leu. It improves selective analysis for amino acids and therefore would be applicable in medicine, diagnosis, and single‐molecule peptide sequencing.
Photoresponsive Small Molecule Inhibitors for the Remote Control of Enzyme Activity
Authors: Laczi Dóra , Johnstone Mark D. , Fleming Cassandra L. 
Published: April 2022

AbstractThe development of new and effective therapeutics is reliant on the ability to study the underlying mechanisms of potential drug targets in live cells and multicellular systems. A persistent challenge in many drug development programmes is poor selectivity, which can obscure the mechanisms involved and lead to poorly understood modes of action. In efforts to improve our understanding of these complex processes, small molecule inhibitors have been developed in which their OFF/ON therapeutic activity can be toggled using light. Photopharmacology is devoted to using light to modulate drugs. Herein, we highlight the recent progress made towards the development of light‐responsive small molecule inhibitors of selected enzymatic targets. Given the size of this field, literature from 2015 onwards has been reviewed.
Cribriform pattern disease over‐represented in pelvic lymph node metastases identified on 68GA PSMA‐PET/CT
Authors: Bolton Damien , Hong Anne , Papa Nathan , Perera Marlon , Kelly Brian , Duncan Catriona , Clouston David , Lawrentschuk Nathan 
Published: April 2022

AbstractObjectivesTo determine whether any specific histologic subtype of prostate cancer was preferentially represented in pelvic lymph node metastases identified on 68GA‐PSMA‐PET/CT.Subjects and MethodsA consecutive series of 66 men with biochemical recurrent prostate cancer was evaluated with 68GA‐PSMA‐PET/CT. Where disease was confined to pelvic lymph nodes, patients were offered salvage extended pelvic lymph node dissection. Twenty patients ultimately proceeded to extended bilateral template pelvic lymph node dissection. Lymph node positivity and the histologic subtype of apparent cancer were assessed, as was PSA response to this intervention.ResultsMean PSA at time of PSMA scanning for patients undergoing lymphadenectomy was 2.49 (n = 20, range 0.21–12.0). In 16 of 20 patients, there was evidence of metastatic cribriform pattern prostate cancer in excised nodes (100% cribriform pattern in 11/16). Only four of 20 patients had no evidence of this histologic subtype of disease. PSA response was not related to the presence or proportional amount of cribriform pattern disease identified.ConclusionsCribriform pattern adenocarcinoma appears to be the histologic subtype preferentially identified in pelvic lymph nodes on 68GA‐PSMA‐PET/CT. The use of PSMA‐PET may be particularly valuable in staging of primary or biochemically recurrent prostate cancer in patients with cribriform pattern disease detected on initial biopsy or radical prostatectomy. Further research is required to further confirm the observed association.
Interaction between caffeic acid phenethyl ester and protease: monitoring by spectroscopic and molecular docking approaches
Authors: Nai Xiao , Chen Yanrong , Zhang Qian , Hao Shengyu , Xuan Hongzhuan , Liu Jie 
Published: April 2022

AbstractThe interaction of one anticancer drug (caffeic acid phenethyl ester; CAPE) with three proteases (trypsin, pepsin and α‐chymotrypsin) has been investigated with multispectral methods and molecular docking. As an active components in propolis, the findings are of great benefit to metabolism, design, and structural modification of drugs. The results show that CAPE has an obvious ability to quench the trypsin, pepsin, or α‐chymotrypsin fluorescence mainly through a static quenching procedure. Trypsin has the largest binding affinity to CAPE, and α‐chymotrypsin has the smallest binding affinity to CAPE. The data obtained from thermodynamic parameters and molecular docking prove that the spontaneously interaction between CAPE and each protease is mainly due to a combination of van der Waals (vdW) force and hydrogen bond (H‐bond), controlled by an enthalpy‐driven process. The binding force, strength, position, and the number of H‐bond are further obtained from the results of molecular docking. Through ultraviolet spectroscopy, dynamic light scattering and circular dichroism experiments, the change in the protease secondary structure induced by CAPE was observed. Additionally, the addition of protease had a positive effect on the antioxidative activity of CAPE, and α‐chymotrypsin has the greatest effect on the removal of 2,2‐diphenyl‐1‐picrylhydrazyl free radicals by CAPE.
Systems metabolic engineering of Streptomyces venezuelae for the enhanced production of pikromycin
Authors: Cho Min Kyung , Lee Byung Tae , Kim Hyun Uk , Oh Min‐Kyu 
Published: April 2022

AbstractPikromycin is an important precursor of drugs, for example, erythromycin. Hence, systems metabolic engineering for the enhanced pikromycin production can contribute to the development of pikromycin‐related drugs. In this study, metabolic genes in Streptomyces venezuelae were systematically engineered for enhanced pikromycin production. For this, a genome‐scale metabolic model of S. venezuelae was reconstructed and simulated, which led to the selection of 11 metabolic gene targets. These metabolic genes, including four overexpression targets and seven knockdown targets, were individually engineered first. Next, two overexpression targets and two knockdown targets were selected based on the 11 strains' production performances to engineer two to four of these genes together for the potential synergistic effects on the pikromycin production. As a result, the NM1 strain with AQF52_RS24510 (methenyltetrahydrofolate cyclohydrolase/methylenetetrahydrofolate dehydrogenase) overexpression and AQF52_RS30320 (sulfite reductase) knockdown showed the best production performance among all the 22 strains constructed in this study. Fed‐batch fermentation of the NM1 strain produced 295.25 mg/L of pikromycin, by far the best production titer using the native producer S. venezuelae, to the best of our knowledge. The systems metabolic engineering strategy demonstrated herein can also be applied to the overproduction of other secondary metabolites using S. venezuelae.