Exploring the pyro-phototronic effect for giant lateral photoresponse in an ITO/CdS/Si heterojunction position-sensitive detector.

The demand for a high-performance position sensitive detector (PSD), a novel type of photoelectric sensor, is increasing due to advancements in digitization and automation technology. Cadmium sulfide (CdS), a non-centrosymmetric material, holds significant potential in photoelectric devices. However, the pyroelectric effect of CdS in PSDs and its influence on lateral photoresponse are still unknown. In this work, we fabricated an ITO/CdS/Si heterojunction using chemical bath deposition (CBD) and investigated the pyro-phototronic effect under nonuniform illumination. The theory of electron-hole pairs' generation, separation, and carrier diffusion was carefully considered to understand the underlying mechanisms. Our experimental findings revealed that the device exhibited an exceptionally high position sensitivity (PS) of 1061.3 mV/mm, surpassing the generally observed PS of 655.1 mV/mm induced by single photovoltaic effect by 160.5%. Meanwhile, the PSD demonstrated rapid response times of 0.01 and 0.04 ms, respectively. Moreover, the influence of ambient temperature and electrode distance on the pyro-phototronic effect was well analyzed. Notably, the PSD exhibited remarkable stability even at ambient temperatures up to 150 °C. Despite the considerable working distance of 11 mm, the PS of the PSD remained at 128.99 mV/mm. These findings provide valuable theoretical and experimental foundations for optimizing the design and implementation of high-performance large working distance PSDs.

Self-Powered MAPbI3 Heterojunction Photodetector with Gradient-Level Electron Transport Layers and Dual Pyro-Phototronic Effects.

An electron transport layer (ETL) with a suitable gradient energy level can enhance electron transfer, suppress carrier recombination, and effectively improve the photoresponse of photodetectors (PDs). In this letter, a series of ITO/ZnO/CdS/MAPbI3/Spiro-OMeTAD heterojunction PDs were prepared by incorporating a ZnO layer at the CdS/ITO interface upon varying the thickness from 0 to 95 nm. The optimized band arrangement in the PD results in an excellent self-powering ability and improved photoresponse. Moreover, both the photovoltaic and pyroelectric responses strongly correlate with the thickness of the ZnO layer. The PD with an optimal ZnO thin film thickness of 50 nm achieves a huge responsivity (R) of 1.19 × 104 V/W and detectivity (D) of 2.22 × 109 Jones, primarily due to the strengthened pyro-phototronic effects enabled by the dual ETL layers. In addition, the enhanced pyroelectric effect broadens the spectral range of the PD to 360-1550 nm, largely surpassing the band gap of the heterojunction.

Dynamic remodeling of actin networks by cyclase-associated protein and CAP-Abp1 complexes.

How actin filaments are spatially organized and remodeled into diverse higher-order networks in vivo is still not well understood. Here, we report an unexpected F-actin "coalescence" activity driven by cyclase-associated protein (CAP) and enhanced by its interactions with actin-binding protein 1 (Abp1). We directly observe S. cerevisiae CAP and Abp1 rapidly transforming branched or linear actin networks by bundling and sliding filaments past each other, maximizing filament overlap, and promoting compaction into bundles. This activity does not require ATP and is conserved, as similar behaviors are observed for the mammalian homologs of CAP and Abp1. Coalescence depends on the CAP oligomerization domain but not the helical folded domain (HFD) that mediates its functions in F-actin severing and depolymerization. Coalescence by CAP-Abp1 further depends on interactions between CAP and Abp1 and interactions between Abp1 and F-actin. Our results are consistent with a mechanism in which the formation of energetically favorable sliding CAP and CAP-Abp1 crosslinks drives F-actin bundle compaction. Roles for CAP and CAP-Abp1 in actin remodeling in vivo are supported by strong phenotypes arising from deletion of the CAP oligomerization domain and by genetic interactions between sac6Δ and an srv2-301 mutant that does not bind Abp1. Together, these observations identify a new actin filament remodeling function for CAP, which is further enhanced by its direct interactions with Abp1.

Broadband Self-Powered CdS ETL-Based MAPbI3 Heterojunction Photodetector Induced by a Photovoltaic-Pyroelectric-Thermoelectric Effect.

CdS, with a noncentrosymmetric structure, is thought as an important electron transport layer (ETL) in perovskite-based devices, but its pyroelectric effect, which can efficiently modulate the optoelectronic processes, is not well explored. In this work, a MAPbI3 heterojunction of CdS/MAPbI3/Spiro-OMeTAD with a c-axis preferred oxygen-doped CdS ETL is developed as a high-performance photodetector (PD). This PD exhibits a stable self-powered property in the spectral range of ∼360-780 nm due to its excellent photovoltaic effect. Moreover, the light-induced pyroelectric potential in the CdS ETL is demonstrated to be an efficient approach for improving the photoresponses, and different effects are observed for different laser irradiations, which can be well understood from their working mechanisms. Upon 450 nm laser irradiation, the photovoltage responsivity (R) is greatly improved from 596.9 to 6383.6 V/W with an increment of 1069.54%. In addition, the response spectrum is also extended outside the bandgap restriction of the MAPbI3 to 1550 nm due to both the pyroelectric and photothermoelectric effects, which is a big breakthrough for the perovskite heterojunction PD. Through turning the external bias voltage and ambient temperature, the coupling mechanisms of the pyroelectric and photovoltaic effects are further analyzed. This work provides an important understanding of designing the CdS ETL-based perovskite heterojunction for broadband high-performance photoelectric devices by introducing the pyroelectric effect.

Greatly improved photoresponse in the MAPbBr3/Si heterojunction by introducing an ITO layer and optimizing MAPbBr3 layer thickness.

In this paper, a CH3NH3(MA)PbBr3/Si heterojunction photodetector (PD) is prepared, and a simple method is proposed to improve the performance by introducing an ITO conductive layer and modulating thickness of the MAPbBr3 layer. The results indicate that the MAPbBr3/Si heterojunction PD exhibits an ultra-broadband photoresponse ranging from 405 to 1064 nm, and excellent performances with the responsivity (R) of 0.394 mA/W, detectivity (D) of 0.11×1010 Jones, and response times of ∼2176/∼257 ms. When adding the ITO layer, the R and D are greatly improved to 0.426 A/W and 5.17×1010 Jones, which gets an increment of 1.08×105% and 4.7×103%, respectively. Meanwhile, the response times are reduced to ∼130/∼125 ms, and a good environmental stability is obtained. Moreover, it is found that the photoresponse is strongly dependent on the thickness of the MAPbBr3 layer. By modulating the MAPbBr3 layer thickness from ∼85 to ∼590 nm, the performances are further improved with the best R of ∼0.87 A/W, D of ∼1.92×1011 Jones, and response times of ∼129/∼130 ms achieved in the ∼215 nm-thick PD.

Synthesis and structure-bactericidal activity relationships of non-ketolides: 9-Oxime clarithromycin 11,12-cyclic carbonate featured with three-to eight-atom-length spacers at 3-OH.

In general, potent non-ketolide versions of erythromycin possessed conformationally constricted two- or three-atom-length sidechains at 3-OH. Novel 14-membered non-ketolides possessing long spacers beyond three-atom length were evaluated for antibacterial activity. The most potent one is 34a, featuring a five-atom-length flexible linker from of a pyridine ring to the aglycone. Conversion of the pyridine of 34a to other aryl groups, changing the linker's length of 34a to longer or shorter ones, and variation of the linker flexibility to a rigid olefin or alkyne led to decreased antibacterial activity. The hybrids of macrolides and quinolones 28b, 31 and 34b possessing various sidechains, unlike their 15-membered counterparts, were ineffective compared to 34a. Similar to the marketed ketolide telithromycin, the non-ketolide 34a proved to be a time-dependent bactericidal agent, but it exhibited superior in vivo pharmacokinetic properties such as longer half-life, higher plasma concentration, lower clearance and shorter time to reach the highest drug concentration relative to telithromycin. Molecular docking suggested 34a might π - π interact with the bacterial ribosomal RNA base G2505Ec. This study suggested that the bacteriostatic agent erythromycin can be structurally modified to afford a new bactericidal chemotype that targets the ribosome and is superior to ciprofloxacin with regard to its minimum bactericidal concentration.

Abp1 promotes Arp2/3 complex-dependent actin nucleation and stabilizes branch junctions by antagonizing GMF.

Formation and turnover of branched actin networks underlies cell migration and other essential force-driven processes. Type I nucleation-promoting factors (NPFs) such as WASP recruit actin monomers to Arp2/3 complex to stimulate nucleation. In contrast, mechanisms of type II NPFs such as Abp1 (also known as HIP55 and Drebrin-like protein) are less well understood. Here, we use single-molecule analysis to investigate yeast Abp1 effects on Arp2/3 complex, and find that Abp1 strongly enhances Arp2/3-dependent branch nucleation by stabilizing Arp2/3 on sides of mother filaments. Abp1 binds dynamically to filament sides, with sub-second lifetimes, yet associates stably with branch junctions. Further, we uncover a role for Abp1 in protecting filament junctions from GMF-induced debranching by competing with GMF for Arp2/3 binding. These data, combined with EM structures of Abp1 dimers bound to Arp2/3 complex in two different conformations, expand our mechanistic understanding of type II NPFs.

Structural basis of actin monomer re-charging by cyclase-associated protein.

Actin polymerization powers key cellular processes, including motility, morphogenesis, and endocytosis. The actin turnover cycle depends critically on "re-charging" of ADP-actin monomers with ATP, but whether this reaction requires dedicated proteins in cells, and the underlying mechanism, have remained elusive. Here we report that nucleotide exchange catalyzed by the ubiquitous cytoskeletal regulator cyclase-associated protein (CAP) is critical for actin-based processes in vivo. We determine the structure of the CAP-actin complex, which reveals that nucleotide exchange occurs in a compact, sandwich-like complex formed between the dimeric actin-binding domain of CAP and two ADP-actin monomers. In the crystal structure, the C-terminal tail of CAP associates with the nucleotide-sensing region of actin, and this interaction is required for rapid re-charging of actin by both yeast and mammalian CAPs. These data uncover the conserved structural basis and biological role of protein-catalyzed re-charging of actin monomers.

Structural Basis of Arp2/3 Complex Inhibition by GMF, Coronin, and Arpin.

The evolutionarily conserved Arp2/3 complex plays a central role in nucleating the branched actin filament arrays that drive cell migration, endocytosis, and other processes. To better understand Arp2/3 complex regulation, we used single-particle electron microscopy to compare the structures of Arp2/3 complex bound to three different inhibitory ligands: glia maturation factor (GMF), Coronin, and Arpin. Although the three inhibitors have distinct binding sites on Arp2/3 complex, they each induced an "open" nucleation-inactive conformation. Coronin promoted a standard (previously described) open conformation of Arp2/3 complex, with the N-terminal ß-propeller domain of Coronin positioned near the p35/ARPC2 subunit of Arp2/3 complex. GMF induced two distinct open conformations of Arp2/3 complex, which correlated with the two suggested binding sites for GMF. Furthermore, GMF synergized with Coronin in inhibiting actin nucleation by Arp2/3 complex. Arpin, which uses VCA-related acidic (A) motifs to interact with the Arp2/3 complex, induced the standard open conformation, and two new masses appeared at positions near Arp2 and Arp3. Furthermore, Arpin showed additive inhibitory effects on Arp2/3 complex with Coronin and GMF. Together, these data suggest that Arp2/3 complex conformation is highly polymorphic and that its activities can be controlled combinatorially by different inhibitory ligands.

Synthesis and structure-activity relationships of novel 9-oxime acylides with improved bactericidal activity.

9-Oxime acylides have different SAR and binding modes from 9-oxime ketolides. An aminopyridyl or carbamoylpyridyl group anchored at the end of the 9-oxime 2-propargyl group is beneficial for antimicrobial activity. Both the 2-pyridyl and 3-pyridyl groups derived from 3-OH have stacking interactions with the base pair G2505/C2610 (Escherichia coli numbering) of the bacterial rRNA. Compounds 3 presented characteristic features that belong to bactericidal agents when used against constitutive-erm resistant Staphylococcus aureus, susceptible and mef-encoded Streptococcus pneumoniae, inducible-erm resistant Streptococcus pyogenes, and Moraxella catarrhalis. A docking model indicated that the carbamoylpyridyl group of 3h may hydrogen bond to G2061 in addition to π-π stacking over the adenine of A2062 that proved to gate the tunnel for the egress of the nascent peptide. This study suggests that the 9-oxime acylides possess a bactericidal mechanism that is different from the traditional near-complete inhibition of protein synthesis. These studies provide a foundation for the rational design of macrolide antibiotics.