Structural Isomeric Effect on Spin Transport in Molecular Semiconductors.

Molecular semiconductor (MSC) is a promising candidate for spintronic applications benefiting from its long spin lifetime caused by light elemental-composition essence and thus weak spin-orbit coupling (SOC). According to current knowledge, the SOC effect, normally dominated by the elemental composition, is the main spin-relaxation causation in MSCs, and thus the molecular structure-induced SOC change is one of the most concerned issues. In theoretical study, molecular isomerism, a most prototype phenomenon, has long been considered to possess little difference on spin transport previously, since elemental compositions of isomers are totally the same. However, here in this study, quite different spin-transport performances are demonstrated in ITIC and its structural isomers BDTIC experimentally, for the first time, though the charge transport and molecular stacking of the two films are very similar. By further experiments of electron-paramagnetic resonance and density-functional-theory calculations, it is revealed that noncovalent-conformational locks (NCLs) formed in BDTIC can lead to enhancement of SOC and thus decrease the spin lifetime. Hence, this study suggests the influences from the structural-isomeric effect must be considered for developing highly efficient spin-transport MSCs, which also provides a reliable theoretical basis for solving the great challenge of quantificational measurement of NCLs in films in the future.

Two natural compounds as potential inhibitors against the Helicobacter pylori and Acinetobacter baumannii IspD enzymes.

In a vast majority of bacteria, protozoa and plants, the methylerythritol phosphate (MEP) pathway is utilized for the synthesis of isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), which are precursors for isoprenoids. Isoprenoids, such as cholesterol and coenzyme Q, play a variety of crucial roles in physiological activities, including cell-membrane formation, protein degradation, cell apoptosis, and transcription regulation. In contrast, humans employ the mevalonate (MVA) pathway for the production of IDP and DMADP, rendering proteins in the MEP pathway appealing targets for antimicrobial agents. This pathway consists of seven consecutive enzymatic reactions, of which 4-diphosphocytidyl-2C-methyl-D-erythritol synthase (IspD) and 2C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (IspF) catalyze the third and fifth steps, respectively. In this study, we characterized the enzymatic activities and protein structures of Helicobacter pylori IspDF and Acinetobacter baumannii IspD. Then, using the direct interaction-based thermal shift assay, we conducted a compound screening of an approved drug library and identified 27 hit compounds potentially binding to AbIspD. Among them, two natural products, rosmarinic acid and tanshinone IIA sodium sulfonate, exhibited inhibitory activities against HpIspDF and AbIspD, by competing with one of the substrates, MEP. Moreover, tanshinone IIA sodium sulfonate also demonstrated certain antibacterial effects against H. pylori. In summary, we identified two IspD inhibitors from approved ingredients, broadening the scope for antibiotic discovery targeting the MEP pathway.

Cyclic peptides discriminate BCL-2 and its clinical mutants from BCL-XL by engaging a single-residue discrepancy.

Overexpressed pro-survival B-cell lymphoma-2 (BCL-2) family proteins BCL-2 and BCL-XL can render tumor cells malignant. Leukemia drug venetoclax is currently the only approved selective BCL-2 inhibitor. However, its application has led to an emergence of resistant mutations, calling for drugs with an innovative mechanism of action. Herein we present cyclic peptides (CPs) with nanomolar-level binding affinities to BCL-2 or BCL-XL, and further reveal the structural and functional mechanisms of how these CPs target two proteins in a fashion that is remarkably different from traditional small-molecule inhibitors. In addition, these CPs can bind to the venetoclax-resistant clinical BCL-2 mutants with similar affinities as to the wild-type protein. Furthermore, we identify a single-residue discrepancy between BCL-2 D111 and BCL-XL A104 as a molecular "switch" that can differently engage CPs. Our study suggests that CPs may inhibit BCL-2 or BCL-XL by delicately modulating protein-protein interactions, potentially benefiting the development of next-generation therapeutics.

Strain-restricted transfer of ferromagnetic electrodes for constructing reproducibly superior-quality spintronic devices.

Spintronic device is the fundamental platform for spin-related academic and practical studies. However, conventional techniques with energetic deposition or boorish transfer of ferromagnetic metal inevitably introduce uncontrollable damage and undesired contamination in various spin-transport-channel materials, leading to partially attenuated and widely distributed spintronic device performances. These issues will eventually confuse the conclusions of academic studies and limit the practical applications of spintronics. Here we propose a polymer-assistant strain-restricted transfer technique that allows perfectly transferring the pre-patterned ferromagnetic electrodes onto channel materials without any damage and change on the properties of magnetism, interface, and channel. This technique is found productive for pursuing superior-quality spintronic devices with high controllability and reproducibility. It can also apply to various-kind (organic, inorganic, organic-inorganic hybrid, or carbon-based) and diverse-morphology (smooth, rough, even discontinuous) channel materials. This technique can be very useful for reliable device construction and will facilitate the technological transition of spintronic study.

Metagenomic next-generation sequencing on bronchoalveolar lavage fluid to contribute to diagnosis of subclinical pulmonary tuberculosis with scarce sputum and negative smear in a patient mimicking adult- onset still's disease: A case report.

Extremely high serum ferritin, which is regarded as a marker of adult-onset still's disease (AOSD), has been rarely observed in patients with TB. We report a case of TB diagnose by metagenomic next-generation sequencing(mNGS) who presented with clinical criteria of AOSD and extreme hyperferritinemia, which posed a diagnostic confusion. TB presenting with major clinical criteria of AOSD should be notable. Since TB remains a potentially curable disease, an awareness of its' protean manifestations is essential. A typical or even normal outcomes of clinical, microbiochemical, and radiologic evaluation should not be overlooked and dedicated diagnostic work-up should be performed for TB diagnosis. For equivocal cases, mNGS could be helpful.

All-polarization-maintaining, efficiently wavelength-tunable, Er-doped mode-locked fiber laser with a compact reflective Lyot filter.

Wavelength tunable mode-locked fiber lasers have highly potential applications in precision spectroscopy, nonlinear microscopy and photonic sensing. Here, we present a compact and thermal-sensitive reflective Lyot filter and utilize it for all-polarization-maintaining efficiently wavelength-tunable Er-doped carbon-nanotube-mode-locked laser for the first time, to the best of our knowledge. The output wavelength of the laser can be tuned from 1544.46 nm to 1572.71 nm, with a wide tuning range of 28.25 nm, and a remarkable tuning efficiency of 0.589 nm/°C, when the angle-spliced fiber is only 8.2 cm and the free spectral range of the filter is 31.32 nm. Dual-wavelength mode-locking is also achieved at boundary temperatures when increasing the pump power. Due to its compact size and reflection configuration, the proposed reflective Lyot filter is promising for realizing highly efficient wavelength tuning and multiwavelength generation in all-polarization-maintaining fiber lasers where reflective filters are needed.

Strategies and applications of generating spin polarization in organic semiconductors.

The advent of spintronics has undoubtedly revolutionized data storage, processing, and sensing applications. Organic semiconductors (OSCs), characterized by long spin relaxation times (>µs) and abundant spin-dependent properties, have emerged as promising materials for advanced spintronic applications. To successfully implement spin-related functions in organic spintronic devices, the four fundamental processes of spin generation, transport, manipulation, and detection form the main building blocks and are commonly in demand. Thereinto, the effective generation of spin polarization in OSCs is a precondition, but in practice, this has not been an easy task. In this context, considerable efforts have been made on this topic, covering novel materials systems, spin-dependent theories, and device fabrication technologies. In this review, we underline recent advances in external spin injection and organic property-induced spin polarization, according to the distinction between the sources of spin polarization. We focused mainly on summarizing and discussing both the physical mechanism and representative research on spin generation in OSCs, especially for various spin injection methods, organic magnetic materials, the chiral-induced spin selectivity effect, and the spinterface effect. Finally, the challenges and prospects that allow this topic to continue to be dynamic were outlined.

Emerging Spintronic Materials and Functionalities.

The explosive growth of the information era has put forward urgent requirements for ultrahigh-speed and extremely efficient computations. In direct contrary to charge-based computations, spintronics aims to use spins as information carriers for data storage, transmission, and decoding, to help fully realize electronic device miniaturization and high integration for next-generation computing technologies. Currently, many novel spintronic materials have been developed with unique properties and multifunctionalities, including organic semiconductors (OSCs), organic-inorganic hybrid perovskites (OIHPs), and 2D materials (2DMs). These materials are useful to fulfill the demand for developing diverse and advanced spintronic devices. Herein, these promising materials are systematically reviewed for advanced spintronic applications. Due to the distinct chemical and physical structures of OSCs, OIHPs, and 2DMs, their spintronic properties (spin transport and spin manipulation) are discussed separately. In addition, some multifunctionalities due to photoelectric and chiral-induced spin selectivity (CISS) are overviewed, including the spin-filter effect, spin-photovoltaics, spin-light emitting devices, and spin-transistor functions. Subsequently, challenges and future perspectives of using these multifunctional materials for the development of advanced spintronics are presented.

Recent Advances in Organic Photovoltaic Materials Based on Thiazole-Containing Heterocycles.

Organic solar cells (OSCs) have achieved great progress, driven by the rapid development of wide bandgap electron donors and narrow bandgap non-fullerene acceptors (NFAs). Among a large number of electron-accepting (A) building blocks, thiazole (Tz) and its derived fused heterocycles have been widely used to construct photovoltaic materials, especially conjugated polymers. Benefiting from the electron deficiency, rigidity, high planarity, and enhanced intra/intermolecular interactions of Tz-containing heterocycles, some related photovoltaic materials exhibit proper energy levels, optimized molecular aggregation, and active layer morphology, leading to excellent photovoltaic performance. This review focuses on the progress of Tz-based photovoltaic materials in the field of OSCs. First, the Tz-based donor and acceptor photovoltaic materials are reviewed. Then, the materials based on promising Tz-containing heterocycles, mainly including thiazolo[5,4-d]thiazole (TzTz), benzo[1,2-d:4,5-d']bis(thiazole) (BBTz), and benzo[d]thiazole (BTz) are summarized and discussed. In addition, the new emerging Tz-fused structures and their application in OSCs are introduced. Finally, perspectives and outlooks for the further development of Tz-containing heterocycle-based photovoltaic materials are proposed.

Fast wavelength-swept polarization maintaining all-fiber mode-locked laser based on a piezo-stretched fiber Lyot filter.

We demonstrate for the first time a strain-controlled all polarization-maintaining (PM) fiber Lyot filter based on a piezoelectric lead zirconate titanate (PZT) fiber stretcher. This filter is implemented in an all-PM mode-locked fiber laser to serve as a novel wavelength-tuning mechanism for fast wavelength sweeping. The center wavelength of the output laser can be tuned across a range from 1540 nm to 1567 nm linearly. And the strain sensitivity achieved in the proposed all-PM fiber Lyot filter is 0.052nm/µÎµ, which is 43 times higher than that achievable by other strain-controlled filters such as a fiber Bragg grating filter (0.0012nm/µÎµ). Wavelength-swept rates up to 500 Hz and wavelength tuning speeds up to 13,000 nm/s are demonstrated, which is hundreds of times faster than what is attainable with conventional sub-picosecond mode-locked lasers based on mechanical tuning methods. This highly repeatable and swift wavelength-tunable all-PM fiber mode-locked laser is a promising source for applications requiring fast wavelength tunability, such as coherent Raman microscopy.

Continuous Room-Temperature Spin-Injection Modulation Achieved by Spin-Filtering Competition in Molecular Spin Valves.

Abundant spin-related phenomena that originate from interfaces between ferromagnetic electrodes and molecular semiconductors have greatly enriched research in spintronics, and they are considered promising for realizing novel spintronic functionalities in the future. However, despite great effort, the interfacial effect cannot be precisely controlled to achieve steady and predictable functions, especially at room temperature, and this has gradually become a significant bottleneck in the development of molecular spintronics. In this study, an innovative spin-filtering-competition mechanism is proposed to continuously modulate the interfacial effect in molecular spin valves at room temperature. To form this novel mechanism, the original spin-filtering effect from pure cobalt competes with the newly generated one, which is induced by the bonding effect between cobalt and lithium fluoride. Subsequently, by precisely controlling competition through lithium fluoride coverage on the cobalt surface, continuous modulation of the spin-injection process can be successfully achieved at room temperature. Spin polarization of the injected current and magnetoresistance effect can be actively controlled or their sign can be completely reversed through this novel mechanism. This study provides an innovative approach and theory for precisely controlling spin-related interfacial effects, which may further promote the scientific and technological development of spintronics.

Room-Temperature Spin Transport in Metal Nanocluster-Based Spin Valves.

As a new type of inorganic-organic hybrid semiconductor, quantum-confined atomically precise metal nanoclusters (MNCs) have been widely applied in the fields of chemical sensing, optical imaging, biomedicine and catalysis. Herein, we successfully design and fabricate the first example of MNC-based spin valves (SVs) that exhibit remarkable magnetoresistance (MR) value up to 1.6 % even at room temperature (300 K). The concomitant photoresponse of MNC-based SVs unambiguously confirms that the spin-polarized electron transmission takes place across the MNC interlayer. Furthermore, the spin-dependent transport property of MNC-based SVs is largely varied by changing the atomic structure of MNCs. Both experimental proofs and quantum chemistry calculations reveal that the atomic structure-discriminative spin transport behavior is attributed to the distinct spin-orbit coupling (SOC) effect of MNCs.

Structures of NPAS4-ARNT and NPAS4-ARNT2 heterodimers reveal new dimerization modalities in the bHLH-PAS transcription factor family.

Neuronal PER-ARNT-SIM (PAS) domain protein 4 (NPAS4) is a protective transcriptional regulator whose dysfunction has been linked to a variety of neuropsychiatric and metabolic diseases. As a member of the basic helix-loop-helix PER-ARNT-SIM (bHLH-PAS) transcription factor family, NPAS4 is distinguished by an ability to form functional heterodimers with aryl hydrocarbon receptor nuclear translocator (ARNT) and ARNT2, both of which are also bHLH-PAS family members. Here, we describe the quaternary architectures of NPAS4-ARNT and NPAS4-ARNT2 heterodimers in complexes involving DNA response elements. Our crystallographic studies reveal a uniquely interconnected domain conformation for the NPAS4 protein itself, as well as its differentially configured heterodimeric arrangements with both ARNT and ARNT2. Notably, the PAS-A domains of ARNT and ARNT2 exhibit variable conformations within these two heterodimers. The ARNT PAS-A domain also forms a set of interfaces with the PAS-A and PAS-B domains of NPAS4, different from those previously noted in ARNT heterodimers formed with other class I bHLH-PAS family proteins. Our structural observations together with biochemical and cell-based interrogations of these NPAS4 heterodimers provide molecular glimpses of the NPAS4 protein architecture and extend the known repertoire of heterodimerization patterns within the bHLH-PAS family. The PAS-B domains of NPAS4, ARNT, and ARNT2 all contain ligand-accessible pockets with appropriate volumes required for small-molecule binding. Given NPAS4's linkage to human diseases, the direct visualization of these PAS domains and the further understanding of their relative positioning and interconnections within the NPAS4-ARNT and NPAS4-ARNT2 heterodimers may provide a road map for therapeutic discovery targeting these complexes.

Full Life-Cycle Lead Management and Recycling Transparent Conductors for Low-Cost Perovskite Solar Cell.

Realizing a full life-cycle management for toxic lead (Pb) and reducing material/manufacture cost are the key steps in determining the commercialization process of perovskite photovoltaics. In this work, we develop full lifecycle material management for a carbon-based perovskite solar cell (C-PSC) to immobilize and recover Pb against environmental pollution, followed by refabrication of C-PSC based on recovered materials and recycled transparent conductors from obsolete devices. Pb immobilization is first achieved by a strong coordination interaction between undercoordinated Pb ions from perovskite and a C═O bond from green pseudohalide ions (pseudo-X), and the resulting C-PSC with the structure of ITO/SnO2/pseudo-X-perovskite/carbon yields an efficiency of 16.63%. Pb from an end-of-life C-PSC is then recovered by dissolving the obsolete perovskite layer into DMF/DMSO precursor solvent, followed by replenishing a certain amount of MAI to guarantee new perovskite layer formation. The refabricated C-PSC based on recovered perovskite and a recycled transparent conductor displays comparable efficiency (15.30%) to that of C-PSC with commercial raw materials, also exceeding the previous efficiency record for C-PSCs based on recycled materials. Such refabricated C-PSC is relatively low-cost.

Improving the Photovoltaic Performance of Dithienobenzodithiophene-Based Polymers via Addition of an Additional Eluent in the Soxhlet Extraction Process.

Dithieno[2,3-d;2',3'-d']benzo[1,2-b;4,5-b']dithiophene (DTBDT) is a kind of pentacyclic aromatic electron-donating unit with unique optoelectronic properties, but it has received less attention in the design of photovoltaic polymers. In this work, we copolymerized DTBDT with the electron-deficient unit of dithieno[3',2':3,4;2″,3″:5,6]benzo[1,2-c][1,2,5]thiadiazole (DTBT) and obtained two polymers, PE55 and PE56, with a synergistic heteroatom substitution strategy. When blended with the classic nonfullerene acceptor Y6, PE55 and PE56 achieve power conversion efficiencies (PCEs) of 13.78% and 14.49%, respectively, which indicates that the introduction of sulfur atoms on the conjugated side chain of the D unit is a promising method to enhance the performance of DTBDT-based polymers. Besides, we utilize dichloromethane and chloroform to separate the low molecular weight (Mw) fractions in the solvent extraction process to obtain PE55-CF and PE56-CB, and the PCEs are further improved to 15.00% and 16.11%, respectively. The stronger π-π stacking, optimized blend film morphology, and higher charge mobilities contribute to the enhanced PCEs for polymers with higher Mw obtained via the multistep solvent extraction strategy. Our results not only provide a simple and effective way to improve the photovoltaic performance of conjugated polymers but also imply that some reported polymers purified from the traditional one-step solvent extraction method might be seriously underestimated.

Polarization-maintaining all-fiber tunable mode-locked laser based on a thermally controlled Lyot filter.

We propose and demonstrate for the first time, to the best of our knowledge, a thermally controlled all polarization-maintaining (PM) fiber Lyot filter. This filter is implemented in an all-PM mode-locked fiber laser to achieve wavelength tunability. When operating in the single-wavelength tunable mode, the center wavelength can be tuned across a range from 1546 nm to 1571 nm. Furthermore, the laser can also operate in a dual-wavelength mode with center wavelengths at 1545 nm and 1571 nm. The temperature sensitivity achieved in our all-PM fiber Lyot filter is 0.602 nm/°C, which is over 46 times higher than other fiber-based filters such as a fiber Bragg grating filter (0.013 nm/°C). This highly stable and versatile wavelength-tunable all-PM fiber mode-locked laser is a promising source for various applications requiring wavelength tunability and/or dual-wavelength output, such as coherent Raman microscopy and dual-comb spectroscopy.

Identification of oleoylethanolamide as an endogenous ligand for HIF-3α.

Hypoxia-inducible factors (HIFs) are α/ß heterodimeric transcription factors modulating cellular responses to the low oxygen condition. Among three HIF-α isoforms, HIF-3α is the least studied to date. Here we show that oleoylethanolamide (OEA), a physiological lipid known to regulate food intake and metabolism, binds selectively to HIF-3α. Through crystallographic analysis of HIF-3 α/ß heterodimer in both apo and OEA-bound forms, hydrogen-deuterium exchange mass spectrometry (HDX-MS), molecular dynamics (MD) simulations, and biochemical and cell-based assays, we unveil the molecular mechanism of OEA entry and binding to the PAS-B pocket of HIF-3α, and show that it leads to enhanced heterodimer stability and functional modulation of HIF-3. The identification of HIF-3α as a selective lipid sensor is consistent with recent human genetic findings linking HIF-3α with obesity, and demonstrates that endogenous metabolites can directly interact with HIF-α proteins to modulate their activities, potentially as a regulatory mechanism supplementary to the well-known oxygen-dependent HIF-α hydroxylation.

A novel energy level detector for molecular semiconductors.

The multifunction of molecule-based devices is always achieved by improving their charge transport characteristics. These characteristics depend strongly on the energy levels of molecular semiconductors, which fundamentally govern the working principle and device performance. Therefore, an accurate measurement of these energy levels is crucial for evaluating the availability of the prepared materials and thus optimizing the device performance. Here, an easy-to-operate three-terminal hot electron transistor has been developed, which comprises a molecular optoelectronic device that records the charge transport. It achieves exceptional properties including the lowest unoccupied molecular orbit level, highest occupied molecular orbit level, higher energy states, and higher electronic bandgap. When compared with existing techniques such as cyclic voltammetry, inverse photoemission spectroscopy, and ultraviolet photoemission spectroscopy, the hot electron transistor provides in-situ characterization and categorizes the measured energy information as intrinsic properties of the molecular semiconductor. Furthermore, we provide an in-depth understanding of the fundamental device-physics, which provides promising guidance for performance optimization.

Electron-deficient TVT unit-based D-A polymer donor for high-efficiency thick-film OSCs.

As the power conversion efficiencies of organic solar cells (OSCs) have been improved continuously in recent years, more attention will be paid to the industrial production and practical application of OSCs. However, there are still many problems to be solved in the process of large-scale production. Among them, reducing the costs of the materials and enhancing the film-thickness tolerance of the active layer are the two key points. Therefore, it is urgent to develop organic semiconductor materials which are easy to synthesize and suitable for the construction of high-efficiency, thick-film OSCs. In this work, we have focused on the (E)-2-[2-(thiophen-2-yl)vinyl]thiophene (TVT) unit because of its unique coplanar structure. And we noticed that TVT was mostly used as an electron-donating unit in the previous reports. However, we have modified TVT into electron-withdrawing unit by the introduction of fluorine atoms/ester groups. And two new donor-acceptor (D-A) copolymers have been obtained by combining the electron-withdrawing TVT unit with benzo[2,1-b:4,5-b']dithiophene (BDT) unit. Among them, the polymer based on the ester modified TVT unit presents excellent photovoltaic performance by virtue of its good solubility and preferable molecular stacking mode, and the corresponding devices also show extraordinarily high-thickness tolerance. The emergence of this new electron-withdrawing TVT unit will undoubtedly further promote the development of low-cost, high-efficiency, thick-film OSCs.

The Application of Organic Semiconductor Materials in Spintronics.

π-Conjugated semiconductors, primarily composed of elements with low atomic number, are regarded as promising spin-transport materials due to the weak spin-orbit coupling interaction and hence long spin relaxation time. Moreover, a large number of additional functions of organic semiconductors (OSCs), such as the abundant photo-electric properties, flexibility, and tailorability, endow the organic spintronic devices more unique properties and functionalities. Particularly, the integration of the photo-electric functionality and excellent spin transport property of OSCs in a single spintronic device has even shown great potential for the realization of spin manipulation in OSCs. In this review, the application of OSCs in spintronic study will be succinctly discussed. As the most important and extensive application, the long-distance spin transport property of OSCs will be discussed first. Subsequently, several multifunctional spintronic devices based on OSCs will be summarized. After that, the organic-based magnets used for the electrodes of spintronic devices will be introduced. Finally, according to the latest progress, spin manipulation in OSCs via novel spintronic devices together with other prospects and challenges will be outlined.