Bright Nonblinking Photoluminescence with Blinking Lifetime from a Nanocavity-Coupled Quantum Dot.

Colloidal quantum dots (QDs) are excellent luminescent nanomaterials for many optoelectronic applications. However, photoluminescence blinking has limited their practical use. Coupling QDs to plasmonic nanostructures shows potential in suppressing blinking. However, the underlying mechanism remains unclear and debated, hampering the development of bright nonblinking dots. Here, by deterministically coupling a QD to a plasmonic nanocavity, we clarify the mechanism and demonstrate unprecedented single-QD brightness. In particular, we report for the first time that a blinking QD could obtain nonblinking photoluminescence with a blinking lifetime through coupling to the nanocavity. We show that the plasmon-enhanced radiative decay outcompetes the nonradiative Auger process, enabling similar quantum yields for charged and neutral excitons in the same dot. Meanwhile, we demonstrate a record photon detection rate of 17 MHz from a colloidal QD, indicating an experimental photon generation rate of more than 500 MHz. These findings pave the way for ultrabright nonblinking QDs, benefiting diverse QD-based applications.

Weight-adaptive joint mixed-precision quantization and pruning for neural network-based equalization in short-reach direct detection links.

Neural network (NN)-based equalizers have been widely applied for dealing with nonlinear impairments in intensity-modulated direct detection (IM/DD) systems due to their excellent performance. However, the computational complexity (CC) is a major concern that limits the real-time application of NN-based receivers. In this Letter, we propose, to our knowledge, a novel weight-adaptive joint mixed-precision quantization and pruning approach to reduce the CC of NN-based equalizers, where only integer arithmetic is taken into account instead of floating-point operations. The NN connections are either directly cutoff or represented by a proper number of quantization bits by weight partitioning, leading to a hybrid compressed sparse network that computes much faster and consumes less hardware resources. The proposed approach is verified in a 50-Gb/s 25-km pulse amplitude modulation (PAM)-4 IM/DD link using a directly modulated laser (DML) in the C-band. Compared with the traditional fully connected NN-based equalizer operated with standard floating-point arithmetic, about 80% memory can be saved at a minimum network size without degrading the system performance. Quantization is also shown to be more suitable to over-parameterized NN-based equalizers compared with NNs selected at a minimum size.

Multiplication-free and hardware-efficient baud-rate timing error detector for Nyquist and faster than Nyquist optical IM/DD systems.

Clock recovery (CR) algorithms that support higher baud rates and advanced modulation formats are crucial for short-distance optical interconnections, and it is desirable to push CR to operate at baud rate with minimal computing resources and power. In this Letter, we proposed a hardware-efficient and multiplication operation-free baud-rate timing error detector (TED) as a solution to meet these demands. Our approach involves employing both the absolute value of samples and the nonlinear sign operation to emphasize the clock tone, which is deteriorated by severe bandwidth limitation in Nyquist and faster than Nyquist (FTN) systems. Through experimental investigations based on a transceiver system with a 3 dB bandwidth of 30 GHz, the proposed baud-rate TED exhibits excellent performance. The proposed scheme successfully achieves clock synchronization of the received signals with the transmitted signals, including 50 GBaud PAM4/8, 80 GBaud PAM4, and up to 120 GBaud PAM4 FTN signals. To the best of our knowledge, the CR based on the proposed baud-rate TED is the most optimal solution for ultrahigh-speed short-reach IM/DD transmission, comprehensively considering the timing jitter, bit error rate (BER), and implementation complexity.

Discovery of P450-Modified Sesquiterpenoids Levinoids A-D through Global Genome Mining.

Cytochrome P450-modified bacterial terpenoids remain in a vast chemical space to be explored. In the present study, we conducted global genome mining of 223,829 bacterial genomes and identified 2892 bacterial terpenoid biosynthetic gene clusters (BGCs) with cytochrome P450 genes. Among these, we selected 562 with multiple P450 enzymes, which were further clustered as 355 gene cluster families by sequence similarity analysis. We then chose lev, a BGC from Streptomyces levis MCCC1A01616, for heterologous expression and discovered four new α-amorphene-type sesquiterpenoids, levinoids A-D (1-4). The structures and absolute configurations of these four new compounds were determined by employing extensive NMR analysis, NMR chemical shift calculations with DP4+, and ECD calculations. Furthermore, levinoid C (3) exhibited a moderate level of neuroprotective activity (EC50 = 21 µM) in the glutamate-induced excitotoxicity cell model. Our findings highlight the untapped chemical diversity of P450-modified bacterial terpenoids, opening new avenues for further exploration and discovery.

Mutagenesis-Derived Resistance to Black Point in Wheat.

Black point, a severe global wheat disease, necessitates deploying resistant cultivars for effective control. However, susceptibility remains prevalent among most wheat cultivars. Identifying new sources of resistance and understanding their mechanisms are crucial for breeding resistant cultivars. This study pinpointed black point resistance in an ethyl methane sulfonate (EMS)-mutagenized wheat population of Wanyuanbai 1 (WYB) and analyzed resistant mutants using RNA-Seq. The findings revealed the following: (i) wyb-18, among 10,008 EMS-mutagenized lines, exhibited robust resistance with significantly lower black point incidence under artificial Bipolaris sorokiniana inoculation in 2020 and 2021 (average incidence of 5.2% over 2 years), markedly reduced compared with WYB (50.9%). (ii) wyb-18 kernels displayed black point symptoms at 12 days after inoculation (dai), 3 days later than WYB. At 15 dai, wyb-18 kernels had isolated black spots, unlike WYB kernels, where the entire embryo turned black. (iii) wyb-18 showed heightened antioxidant enzyme activity, including peroxidase, catalase, and superoxide dismutase. (iv) Analysis of 543 differentially expressed genes between wyb-18 and WYB at 9 dai identified enrichment in the MAPK signaling pathway through KEGG analysis. Ten genes in this pathway exhibited upregulated expression, while one was downregulated in wyb-18. Among these genes, PR1, WRKY11, SAPK5, and TraesCS1A02G326800 (chitin recognition protein) consistently showed upregulation in wyb-18, making them potential candidates for black point resistance. These results offer valuable germplasm resources for breeding and novel insights into the mechanisms of black point resistance.

Influence of Organic Impurities on Fractional Crystallization of NaCl and Na2SO4 from High-Salinity Coal Chemical Wastewater: Thermodynamics and Nucleation Kinetics Analysis.

It is a valid path to realize the zero discharge of coal chemical wastewater by using the fractional crystallization method to recycle the miscellaneous salt in high-salinity wastewater. In this study, the thermodynamics and nucleation kinetics of sodium chloride (NaCl) and sodium sulfate (Na2SO4) crystallization in coal chemical wastewater were systematically studied. Through analyses of solubility, metastable zone width, and induction period, it was found that the impurity dimethoxymethane would increase the solid-liquid interface energy and critical crystal size during the nucleation of Na2SO4. Ternary phase diagrams of the pseudo-ternary Na2SO4-NaCl-H2O systems in simulated wastewater were plotted in the temperature range of 303.15 to 333.15 K, indicating that a co-ionization effect existed between NaCl and Na2SO4, and NaCl had a strong salting out effect on Na2SO4. Finally, the nucleation rate and growth rate of Na2SO4 crystals under simulated wastewater conditions were determined by the intermittent dynamic method, and the crystallization kinetic models of Na2SO4 were established. The crystallization nucleation of Na2SO4 crystals was found to be secondary nucleation controlled by surface reactions. The basic theoretical research of crystallization in this study is expected to fundamentally promote the application of fractional crystallization to realize the resource utilization of high-salinity wastewater in the coal chemical industry.

Discovery of Natural Potent HMG-CoA Reductase Degraders for Lowering Cholesterol.

Exploitation of key protected wild plant resources makes great sense, but their limited populations become the major barrier. A particular strategy for breaking this barrier was inspired by the exploration of a resource-saving fungal endophyte Penicillium sp. DG23, which inhabits the key protected wild plant Schisandra macrocarpa. Chemical studies on the cultures of this strain afforded eight novel indole diterpenoids, schipenindolenes A-H (1-8), belonging to six diverse skeleton types. Importantly, semisyntheses suggested some key nonenzymatic reactions constructing these molecules and provided targeted compounds, in particular schipenindolene A (Spid A, 1) with low natural abundance. Remarkably, Spid A was the most potent HMG-CoA reductase (HMGCR) degrader among the indole diterpenoid family. It degraded statin-induced accumulation of HMGCR protein, decreased cholesterol levels and acted synergistically with statin to further lower cholesterol. Mechanistically, transcriptomic and proteomic profiling suggested that Spid A potentially activated the endoplasmic reticulum-associated degradation (ERAD) pathway to enhance the degradation of HMGCR, while simultaneously inhibiting the statin-activated expression of many key enzymes in the cholesterol and fatty acid synthesis pathways, thereby strengthening the efficacy of statins and potentially reducing the side effects of statins. Collectively, this study suggests the potential of Spid A for treating cardiovascular disease.

Low complexity joint clock recovery and adaptive equalization based on a baud-rate timing phase error detector for short-reach digital coherent transmission.

Digital coherent receivers adopting joint clock recovery and adaptive equalization (JCA) can avoid failures of the adaptive equalizer (AEQ) or clock recovery algorithm (CRA) due to clock asynchrony and chromatic dispersion (CD). But in the previous JCA scheme, the AEQ has a heavy computational load as it has to generate two samples per symbol (SPS) for the subsequent timing phase error detector (TPED) which is the core of the CRA. Furthermore, the previous JCA scheme cannot compensate for receiver skew or accommodate Nyquist signals with small roll-off factors (ROFs). These shortcomings hinder its practical applications in ultrahigh-speed short-reach coherent transmission requiring low power consumption, high spectral efficiency, whilst being sensitive to receiver skew. To solve this problem, we propose a new JCA scheme by integrating a two-section real-valued (RV) AEQ with an all-digital feedback CRA based on a baud-rate TPED versatile for different ROFs. Experiments for 61-GBaud dual-polarization (DP) Nyquist 16QAM signals with an ROF of 0.01 show that, compared with the previous JCA scheme, the proposed scheme can reduce the AEQ computational load by about 70% for 10-km transmission, whilst improving the receiver sensitivity by more than 1.7 dB for a receiver skew of 1.5 ps. As far as we know, the proposed JCA scheme is the most comprehensive and efficient solution for ultrahigh-speed short-reach coherent transmission where CD, receiver skew, clock asynchrony, and Nyquist signals with small ROFs have to be dealt with.

Mechanistic Insight into the Inhibitory Activity of Elasnin-Based Coating against Early Marine Biofilms.

Marine biofilms are multispecies microbial communities on surfaces that are crucial to the marine environment. They cause marine corrosion, biofouling, and transmission of marine pathogens and thus pose a great threat to public health and the maritime industry. To control marine biofilms, effective and environmentally friendly antibiofilm compounds are highly needed. Elasnin is a potent antibiofilm compound that exhibits high efficiency in inhibiting marine biofilms and biofouling, but its mode of action remains unclear. In the present study, multiomic analysis combined with quorum-sensing assays and in silico study revealed that elasnin acted as a signaling molecule in the microbial community. Elasnin promoted the growth of dominant species in the biofilm but deprived their ability of sensing and responding to environmental changes by disturbing their regulations of the two-component system, i.e., the ATP-binding cassette transport system and the bacterial secretion system. Consequently, biofilm maturation and subsequent biofouler settlement were inhibited. Elasnin also exhibited higher antibiofilm efficiency than dichlorooctylisothiazolinone and had low toxicity potential on the embryos and adults of marine medaka fish. Overall, this study provided molecular and ecological insights into elasnin's mode of action, highlighting its application potential in controlling marine biofilms and the feasibility and advantages of using signal molecules to develop eco-friendly technologies.

Quantitative trait loci for resistance to black point caused by Bipolaris sorokiniana in bread wheat.

Black point disease is a serious concern in wheat production worldwide. In this study, we aimed to identify the major quantitative trait loci (QTL) for resistance to black point caused by Bipolaris sorokiniana and develop molecular markers for marker-assisted selection (MAS). A recombinant inbred line (RIL) population derived from a cross between PZSCL6 (highly susceptible) and Yuyou1 (moderately resistant) was evaluated for black point resistance at four locations under artificial inoculation with B. sorokiniana. Thirty resistant and 30 susceptible RILs were selected to form resistant and susceptible bulks, respectively, which were genotyped by the wheat 660 K SNP array. Two hundred and four single-nucleotide polymorphisms (SNPs) were identified, among which 41(20.7%), 34 (17.2%), 22 (11.1%), and 22 (11.1%) were located on chromosomes 5A, 5B, 4B, and 5D, respectively. The genetic linkage map for the RIL population was constructed using 150 polymorphic SSR and dCAPS markers. Finally, five QTL were detected on chromosomes 5A, 5B, and 5D, designated QBB.hau-5A, QBB.hau-5B.1, QBB.hau-5B.2, QBB.hau-5D.1, and QBB.hau-5D.2, respectively. All resistance alleles were contributed by the resistant parent Yuyou1. QBB.hau-5D.1 is likely to be a new locus for black point resistance. The markers Xwmc654 and Xgwm174 linked to QBB.hau-5A and QBB.hau-5D.1, respectively, have potential utility in MAS-based breeding. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01356-6.

Biosynthesis and bioactivities of microbial genotoxin colibactins.

Covering: up to 2021Colibactin(s), a group of secondary metabolites produced by the pks island (clb cluster) of Escherichia coli, shows genotoxicity relevant to colorectal cancer and thus significantly affects human health. Over the last 15 years, substantial efforts have been exerted to reveal the molecular structure of colibactin, but progress is slow owing to its instability, low titer, and elusive and complex biosynthesis logic. Fortunately, benefiting from the discovery of the prodrug mechanism, over 40 precursors of colibactin have been reported. Some key biosynthesis genes located on the pks island have also been characterised. Using an integrated bioinformatics, metabolomics, and chemical synthesis approach, researchers have recently characterised the structure and possible biosynthesis processes of colibactin, thereby providing new insights into the unique biosynthesis logic and the underlying mechanism of the biological activity of colibactin. Early developments in the study of colibactin have been summarised in several previous reviews covering various study periods, whereas the two most recent reviews have focused primarily on the chemical synthesis of colibactin. The present review aims to provide an update on the biosynthesis and bioactivities of colibactin.

High receiver skew-tolerant and hardware-efficient clock recovery for short-reach coherent transmission.

The performance of the high-baud-rate and high-order-modulation-format short-reach coherent transmission systems is sensitive to the in-phase and quadrature (IQ) skew. The conventional receiver IQ skew compensation schemes based on adaptive equalizers (AEQs) suffer from the IQ skew enhanced timing jitter incurred by the clock recovery algorithm (CRA), resulting in a serious sensitivity degradation. In this paper, we first propose a novel multiplication-free timing phase error detector (TPED) with the gain insensitive to the receiver IQ skew and the capability to deal with the complex-valued Nyquist signal with an arbitrary roll-off factor and its real-valued IQ tributaries. Based on the TPED, we then propose a new all-digital feedback CRA able to compensate for the receiver IQ skew. With the novel CRA, the IQ skew enhanced timing jitter is eliminated and the receiver sensitivity can be improved by more than 1 dB for the 61 GBaud dual-polarization Nyquist 16QAM system for an IQ skew of 5 ps. Furthermore, the proposed CRA can reduce the computation complexity of the AEQ by more than 25% compared with the existing schemes by relieving the AEQ from IQ skew compensation. Both numerical simulations and experiments are carried out to validate the advantages of the proposed algorithms. The high-skew-tolerant and low-complexity CRA is a strong candidate for the power-sensitive high-speed short-reach coherent transmission systems.

Multiplication-free timing phase error detector for Nyquist and non-Nyquist optical signals.

A versatile digital coherent receiver capable of handling optical signals with different kinds of pulse shaping schemes (PSSs) is indispensable for future flexible and heterogeneous coherent optical communication networks. Therefore, a low-complexity timing phase error detector (TPED) versatile for all PSSs is of particular interest. In this paper, we propose a TPED suitable for both Nyquist signals with different roll-off factors and non-Nyquist signals. It requires two samples per symbol and involves no multiplications. As far as we know, it has the lowest computation complexity compared with the existing TPEDs used in coherent systems, while incurring no receiver sensitivity penalty. Numerical simulations and experiments are carried out to demonstrate the superior timing performance and PSS versatility of the proposed TPED in both open-loop and closed-loop working conditions. We also implement the novel TPED in a field programmable gate array (FPGA) and verify its real-time clock recovery performance using the 10 Gbaud very low roll-off Nyquist and non-Nyquist quadrature phase shift keying (QPSK) signals.

Bathiapeptides: Polythiazole-Containing Peptides from a Marine Biofilm-Derived Bacillus sp.

Bacteria in marine biofilms are a rich reservoir of natural products. To facilitate novel secondary metabolite discovery, we investigated the metabolic profile of a marine biofilm-derived Bacillus sp. B19-2 by combining bioinformatics and LC-UV-MS analyses. After dereplication and purification of putatively unknown compounds, a new family of compounds 1-8 was uncovered and named bathiapeptides. Structural elucidation using NMR, HRESIMS, ozonolysis, advanced Marfey's analysis, and X-ray diffraction revealed that bathiapeptides are polypeptides that contain a rare polythiazole moiety. These compounds exhibited strong cytotoxicity against Hep G2, HeLa, MCF-7, and MGC-803 cell lines, and the lowest IC50 value was 0.5 µM. An iterative biosynthesis logic in bathiapeptides' biosynthesis was proposed based on the identified chemical structures and putative gene cluster analysis.

Accelerated alkalinity regulation and long-term dry-wet aging durability for bauxite residue remediated with biomass pyrolysis.

Biomass fermentation provides a potential route toward the ecological disposal for the bauxite residue (BR) with high alkalinity issues. However, how to accelerate the remediation of the alkaline problem with a long-term durability is still a big challenge. Herein, we investigated the acceleration of the decomposition of straw toward organic acid species via a pyrolysis strategy as well as the pH stability during long-term dry-wet aging for the treated BR. The pH of pyrolytic BR at 300 °C is stabilized at around 8.90 after 70 days' dry-wet aging. During the aging, the main Ca-contained alkaline minerals of calcite and cancrinite are dissolved and the content of exchangeable Na+ is reduced. This pyrolysis process can decompose straw quickly and produce more organic matters that are easily degraded to fulvic and humic acid as evidenced by 3D fluorescence spectrum analysis. Compared to the fermentation with straw under natural conditions, the alkalinity regulation of BR after pyrolysis is featured with shorter period and lower pH as well as long-term pH stability. Therefore, the synergistic pyrolysis of BR with straw provides an alternative method to address the alkaline issues, which is conducive to promoting the soil formation of BR.

Chaetolactam A, an Azaphilone Derivative from the Endophytic Fungus Chaetomium sp. g1.

Chaetolactam A (1), an unprecedented azaphilone derivative bearing a unique 9-oxa-7-azabicyclo[4.2.1]octan-8-onering system, together with two new compounds, 11-epi-chaetomugilide B (2) and chaetomugilide D (3) was isolated from an endophytic fungus, Chaetomium sp. g1. Notably, extensive NMR data analyses, NMR calculations with DP4 and DP4+ analyses, ECD calculations, and the RDC method were employed to establish the structure of 1. Furthermore, 2 exhibited potent apoptosis induction activity by mediating caspase-3 activation and PARP degradation at 3 µM in HL-60.

3-Hydroxy-4-methyldecanoic Acid-Containing Cyclotetradepsipeptides from an Endolichenic Beauveria sp.

An investigation of an endolichenic Beauveria sp. led to the discovery of seven new cyclotetradepsipeptides, beauveamides A-G (2-8), along with the known beauverolide Ka (1). All incorporate a 3-hydroxy-4-methyldecanoic acid (HMDA) moiety in their structures. Their configuration was determined through Marfey's, J-based configuration analysis, and NMR computational methods, representing the first time that the stereostructures of HMDA-moiety-containing cyclotetradepsipeptides have been established. Compounds 1 and 2 exhibited protecting effects on HEI-OC1 cells at 10 µM, while 1, 4, and 5 could stimulate glucose uptake in cultured rat L6 myoblasts at 50 µM. Compound 1 showed dose-dependent activity in both L6 myoblasts and myotubes.

Challenges of the establishment of rubber-based agroforestry systems: Decreases in the diversity and abundance of ground arthropods.

The global land area devoted to rubber plantations has now reached 13 million hectares, and the further expansion of these rubber plantations at the expense of tropical forests will have significant adverse effects on the ecological environment. Rubber-based agroforestry systems are considered a preferable approach for ameliorating the ecological environment. Many researchers have focused on the positive effects of rubber-based agroforestry systems on the ecological environment, while ignoring the risks involved in the establishment of rubber-based agroforestry systems. The present study investigated the effects of different-aged rubber-based agroforestry systems on the abundance and diversity of ground arthropods. It has been observed that the abundance and taxon richness of ground arthropods generally showed no difference when comparing young and mature rubber plantations. The rubber-based agroforestry systems significantly decreased the understory vegetation species, along with the abundance and taxon richness of ground arthropods compared to the same aged-rubber monoculture plantations. In addition, the change in the abundance and taxon richness of ground arthropods was greatly affected by the understory vegetation species and soil temperature. The abundance and taxon richness of ground arthropods decreased with the decrease in number of species of understory vegetation. The study results indicate that the establishment of rubber-based agroforestry systems have adversely affected the abundance and richness of ground arthropods to an extant greater than expected. Therefore, single, large rubber-based agroforestry systems are not recommended, and the intercropping of rubber and rubber-based agroforestry systems must be designed to promote the migration of ground arthropods between different systems.

miR-204-5p regulates cell proliferation, invasion, and apoptosis by targeting IL-11 in esophageal squamous cell carcinoma.

Esophageal cancer (EC) is the world's eighth most common malignant neoplasm and is ranked as the sixth leading cause of death related to cancer. Aberrant microRNA (miRNA) expression has been reported to be associated with esophageal squamous cell carcinoma. However, the molecular mechanism of miR-204-5p in esophageal squamous cell carcinoma (ESCC) is not clear. Therefore, the aim of this study was to investigate the potential role of miR-204-5p in ESCC. In the present study, we found that miR-204-5p could affect ESCC proliferation, invasion, apoptosis, and cell cycle in cell and mouse models. A dual-luciferase reporter assay showed that miR-204-5p expression was negatively correlated with interleukin-11 (IL-11) expression. IL-11 overexpression reversed the suppressive effects of miR-204-5p in the cell lines. These results indicated that miR-204-5p functions as a tumor suppressor by directly targeting IL-11 in ESCC.

Discovery of isopenicin A, a meroterpenoid as a novel inhibitor of tubulin polymerization.

Microtubules are involved in celluar processes of movement, intracellular trafficking and mitosis, thus microtubule-targeting agents have been widely used in cancer therapy. Herein, we report isopenicin A, a novel meroterpenoid isolated from the plant endophytic fungus of Penicillium sp. sh18, as a novel microtubule binding molecule that efficiently depolymerizes microtubule polymerization to evoke G2/M cell cycle arrest and subsequent cell apoptosis, contributing to proliferation inhibition of human tumor cell lines. The discovery of isopenicin A provides a new chemotype for discovery and development of promising microtubule inhibitors.