Learning the signatures of the human grasp using a scalable tactile glove.

Humans can feel, weigh and grasp diverse objects, and simultaneously infer their material properties while applying the right amount of force-a challenging set of tasks for a modern robot1. Mechanoreceptor networks that provide sensory feedback and enable the dexterity of the human grasp2 remain difficult to replicate in robots. Whereas computer-vision-based robot grasping strategies3-5 have progressed substantially with the abundance of visual data and emerging machine-learning tools, there are as yet no equivalent sensing platforms and large-scale datasets with which to probe the use of the tactile information that humans rely on when grasping objects. Studying the mechanics of how humans grasp objects will complement vision-based robotic object handling. Importantly, the inability to record and analyse tactile signals currently limits our understanding of the role of tactile information in the human grasp itself-for example, how tactile maps are used to identify objects and infer their properties is unknown6. Here we use a scalable tactile glove and deep convolutional neural networks to show that sensors uniformly distributed over the hand can be used to identify individual objects, estimate their weight and explore the typical tactile patterns that emerge while grasping objects. The sensor array (548 sensors) is assembled on a knitted glove, and consists of a piezoresistive film connected by a network of conductive thread electrodes that are passively probed. Using a low-cost (about US$10) scalable tactile glove sensor array, we record a large-scale tactile dataset with 135,000 frames, each covering the full hand, while interacting with 26 different objects. This set of interactions with different objects reveals the key correspondences between different regions of a human hand while it is manipulating objects. Insights from the tactile signatures of the human grasp-through the lens of an artificial analogue of the natural mechanoreceptor network-can thus aid the future design of prosthetics7, robot grasping tools and human-robot interactions1,8-10.

Numerical investigation on the convergence of self-consistent Schrödinger-Poisson equations in semiconductor device transport simulation.

Semiconductor devices at the nanoscale with low-dimensional materials as channels exhibit quantum transport characteristics, thereby their electrical simulation relies on the self-consistent solution of the Schrödinger-Poisson equations. While the non-equilibrium Green's function (NEGF) method is widely used for solving this quantum many-body problem, its high computational cost and convergence challenges with the Poisson equation significantly limit its applicability. In this study, we investigate the stability of the NEGF method coupled with various forms of the Poisson equation, encompassing linear, analytical nonlinear, and numerical nonlinear forms Our focus lies on simulating carbon nanotube field-effect transistors (CNTFETs) under two distinct doping scenarios: electrostatic doping and ion implantation doping. The numerical experiments reveal that nonlinear formulas outperform linear counterpart. The numerical one demonstrates superior stability, particularly evident under high bias and ion implantation doping conditions. Additionally, we investigate different approaches for presolving potential, leveraging solutions from the Laplace equation and a piecewise guessing method tailored to each doping mode. These methods effectively reduce the number of iterations required for convergence.

First report of pepper chlorosis-associated virus infecting tobacco (Nicotiana tabacum) plants in Sichuan Province in China.

Tobacco (Nicotiana tabacum) is an economically important crop in China, and more than 30 viruses have been reported to infect tobacco (Yin et al. 2022). In July 2022, we observed interveinal necrosis on tobacco leaves in fields in Sichuan Province (N 27.9172, E 105.6662) (Fig. 1). Total RNA was isolated from multiple leaves of one plant using an RNAprep Pure Polysaccharide Polyphenol Plant Total RNA Extraction Kit (TIANGEN, Beijing, China). Total RNAs were pooled, and a TruSeq Stranded Total RNA with RiboZero Gold Kit (Illumina, San Diego, CA, USA) was used to eliminate ribosomal RNA. An RNA-Seq library was constructed using VAHTS Universal V6 RNA-seq Library Prep (Nanjing Vazyme, China). High-throughput sequencing was performed on the Illumina DNBseq platform (BGI-ShenZhen, China), which yielded 20,102,087 reads with an average length of 150 nt (total size >6 Gb). Unaligned reads were assembled de novo using SPAdes (Bankevich et al. 2012). Contigs with length ≥200 nt were subjected to local BLASTn and BLASTx analyses against the GenBank nt and nr databases, respectively (Wang et al. 2022). A total of 23 contigs were identified through BLASTx (e-value cut-off = 10 -3), ranging from 631 to 1555 bp long, with 82% to 96% coverage to partial genomic sequences of pepper chlorosis-associated virus (PepCaV-Higashitsuno_2021; Accessions: LC719619 to LC719621) and one contig (6459 bp) with 99% similarity to tobacco mosaic virus (Accession: OP525281) isolate DSMZ PV-0109 from Germany. The complete genome sequence of PepCaV was obtained using primers based on the assembled contigs. The 5'- and 3'-terminal regions of the RNA genome were obtained by 5'- and 3'-rapid amplification of cDNA ends. These amplicons were cloned using the pEASY-Blunt Zero Cloning Kit (TRANSGEN, Nangjing, China) and sequenced by Sanger sequencing. Complete genome sequences of tripartite PepCaV from tobacco samples were 7697, 1808, and 1557 nucleotides long (Accession: OR451987 to OR451989) and showed genome organization typical of the genus Ophiovirus in the family Aspiviridae. The complete sequences of RNA1, RNA2 and RNA3 genome segments shared 92.36%, 90.43%, and 95.24%, nucleotide sequence identities, respectively, with the isolate PepCaV-Higashitsuno_2021 pepper isolate (Accession: LC719619 to LC719621) (Shimomoto et al. 2023), but PepCaV has not been reported to infect N. tabacum. In June 2023, 10 plants collected from each place of Macheng (N 27.9094, E 105.6740), Xiangyang (N 28.0936, E 105.6249) and Moni (N 27.8899, E 105.5936) showing interveinal necrosis symptoms were tested using RT-PCR using PepCaV-MP610-F (5'-TGTTCTCTGCTATGCGGTTG -3') and PepCaV-MP610-R (5'-AGCAATCTCGCACCTGAAGT-3') to product 610bp amplicon. Twenty-five tobacco plants were positive for PepCaV. Single sequence from each location was submitted to GenBank (Accession: PP728631 to PP728633). Sap extracts from the original field leaf samples collected from Sichuan Province were used to mechanically inoculate tobacco plants (10 plants) at the four-leaf stage. After 7 days, leaf samples were tested using RT-PCR assay specific to PepCaV and TMV while samples were positive only for TMV but failed to transmit PepCaV by mechanical inoculation. According to previous literature, ophioviruses may be transmitted though soilborne fungus (Jeong et al. 2014). Further research is needed to understand the transmission, epidemiology, and pathological properties of the PepCaV. To our knowledge, this is the first report documenting natural PepCaV infection of tobacco plants in China, providing a scientific basis for PepCaV infection control in tobacco plantations.

Alternative splicing of CsJAZ1 negatively regulates flavan-3-ol biosynthesis in tea plants.

Flavan-3-ols are abundant in the tea plant (Camellia sinensis) and confer tea with flavor and health benefits. We recently found that alternative splicing of genes is likely involved in the regulation of flavan-3-ol biosynthesis; however, the underlying regulatory mechanisms remain unknown. Here, we integrated metabolomics and transcriptomics to construct metabolite-gene networks in tea leaves, collected over five different months and from five spatial positions, and found positive correlations between endogenous jasmonic acid (JA), flavan-3-ols, and numerous transcripts. Transcriptome mining further identified CsJAZ1, which is negatively associated with flavan-3-ols formation and has three CsJAZ1 transcripts, one full-length (CsJAZ1-1), and two splice variants (CsJAZ1-2 and -3) that lacked 3' coding sequences, with CsJAZ1-3 also lacking the coding region for the Jas domain. Confocal microscopy showed that CsJAZ1-1 was localized to the nucleus, while CsJAZ1-2 and CsJAZ1-3 were present in both the nucleus and the cytosol. In the absence of JA, CsJAZ1-1 was bound to CsMYC2, a positive regulator of flavan-3-ol biosynthesis; CsJAZ1-2 functioned as an alternative enhancer of CsJAZ1-1 and an antagonist of CsJAZ1-1 in binding to CsMYC2; and CsJAZ1-3 did not interact with CsMYC2. In the presence of JA, CsJAZ1-3 interacted with CsJAZ1-1 and CsJAZ1-2 to form heterodimers that stabilized the CsJAZ1-1-CsMYC2 and CsJAZ1-2-CsMYC2 complexes, thereby repressing the transcription of four genes that act late in the flavan-3-ol biosynthetic pathway. These data indicate that the alternative splicing variants of CsJAZ1 coordinately regulate flavan-3-ol biosynthesis in the tea plant and improve our understanding of JA-mediated flavan-3-ol biosynthesis.

Comprehensive analysis of the laccase gene family in tea plant highlights its roles in development and stress responses.

BACKGROUND: Laccase (LAC) is the pivotal enzyme responsible for the polymerization of monolignols and stress responses in plants. However, the roles of LAC genes in plant development and tolerance to diverse stresses are still largely unknown, especially in tea plant (Camellia sinensis), one of the most economically important crops worldwide. RESULTS: In total, 51 CsLAC genes were identified, they were unevenly distributed on different chromosomes and classified into six groups based on phylogenetic analysis. The CsLAC gene family had diverse intron-exon patterns and a highly conserved motif distribution. Cis-acting elements in the promoter demonstrated that promoter regions of CsLACs encode various elements associated with light, phytohormones, development and stresses. Collinearity analysis identified some orthologous gene pairs in C. sinensis and many paralogous gene pairs among C. sinensis, Arabidopsis and Populus. Tissue-specific expression profiles revealed that the majority of CsLACs had high expression in roots and stems and some members had specific expression patterns in other tissues, and the expression patterns of six genes by qRT‒PCR were highly consistent with the transcriptome data. Most CsLACs showed significant variation in their expression level under abiotic (cold and drought) and biotic (insect and fungus) stresses via transcriptome data. Among them, CsLAC3 was localized in the plasma membrane and its expression level increased significantly at 13 d under gray blight treatment. We found that 12 CsLACs were predicted to be targets of cs-miR397a, and most CsLACs showed opposite expression patterns compared to cs-miR397a under gray blight infection. Additionally, 18 highly polymorphic SSR markers were developed, these markers can be widely used for diverse genetic studies of tea plants. CONCLUSIONS: This study provides a comprehensive understanding of the classification, evolution, structure, tissue-specific profiles, and (a)biotic stress responses of CsLAC genes. It also provides valuable genetic resources for functional characterization towards enhancing tea plant tolerance to multiple (a)biotic stresses.

Association between infant birthweight and pelvic floor muscle strength: a population-based cohort study.

BACKGROUND: To assess the relationship between infant birthweight and pelvic floor muscle (PFM) strength in China. METHODS: We performed a retrospective, single-center cohort study of 1575 women delivering vaginally between January 2017 and May 2020. All participants completed pelvic floor examinations within 5-10 weeks after delivery and were evaluated for PFM strength, which was estimated by vaginal pressure. Data were collected from electronic records. We evaluated the association between infant birthweight and vaginal pressure through multivariable-adjusted linear regression analysis. We also performed subgroup analyses stratified by potential confounders. RESULTS: Vaginal pressure decreased as the quartile of birthweight increased (P for trend < 0.001). Beta coefficients were -5.04 (95%CI -7.98 to -2.1), -5.53 (95%CI -8.5 to -2.57), -6.07 (95%CI -9.08 to -3.07) for birthweight quartile 2-4, respectively (P for trend < 0.001), independent of age, postpartum hemorrhage, and the number of vaginal deliveries. In addition, the results of subgroup analyses showed the same patterns across strata. CONCLUSIONS: This study demonstrates that infant birthweight was associated with decreased vaginal pressure in women after vaginal delivery and could be considered a risk factor for decreased PFM strength in the population with vaginal delivery. This association may provide an extra basis for appropriate fetal weight control during pregnancy, and for earlier pelvic floor rehabilitation of postpartum women delivering babies with larger birthweight.

Extracellular vesicles: emerging roles, biomarkers and therapeutic strategies in fibrotic diseases.

Extracellular vesicles (EVs), a cluster of cell-secreted lipid bilayer nanoscale particles, universally exist in body fluids, as well as cell and tissue culture supernatants. Over the past years, increasing attention have been paid to the important role of EVs as effective intercellular communicators in fibrotic diseases. Notably, EV cargos, including proteins, lipids, nucleic acids, and metabolites, are reported to be disease-specific and can even contribute to fibrosis pathology. Thus, EVs are considered as effective biomarkers for disease diagnosis and prognosis. Emerging evidence shows that EVs derived from stem/progenitor cells have great prospects for cell-free therapy in various preclinical models of fibrotic diseases and engineered EVs can improve the targeting and effectiveness of their treatment. In this review, we will focus on the biological functions and mechanisms of EVs in the fibrotic diseases, as well as their potential as novel biomarkers and therapeutic strategies.

Multimodal ultrasound features of breast cancers: correlation with molecular subtypes.

OBJECTIVES: To investigate whether multimodal intratumour and peritumour ultrasound features correlate with specific breast cancer molecular subtypes. METHODS: From March to November 2021, a total of 85 patients with histologically proven breast cancer underwent B-mode, real-time elastography (RTE), colour Doppler flow imaging (CDFI) and contrast-enhanced ultrasound (CEUS). The time intensity curve (TIC) of CEUS was obtained, and the peak and time to peak (TTP) were analysed. Chi-square and binary logistic regression were used to analyse the connection between multimodal ultrasound imaging features and breast cancer molecular subtype. RESULTS: Among 85 breast cancers, the subtypes were as follows: luminal A (36 cases, 42.4%), luminal B (20 cases, 23.5%), human epidermal growth factor receptor-2 positive (HER2+) (16 cases, 18.8%), and triple negative breast cancer (TNBC) (13 cases, 15.3%). Binary logistic regression models showed that RTE (P < 0.001) and CDFI (P = 0.036) were associated with the luminal A cancer subtype (C-index: 0.741), RTE (P = 0.016) and the peak ratio between intratumour and corpus mamma (P = 0.036) were related to the luminal B cancer subtype (C-index: 0.788). The peak ratio between peritumour and intratumour (P = 0.039) was related to the HER2 + cancer subtype (C-index: 0.859), and CDFI (P = 0.002) was associated with the TNBC subtype (C-index: 0.847). CONCLUSIONS: Multimodal ultrasound features could be powerful predictors of specific breast cancer molecular subtypes. The intra- and peritumour CEUS features play assignable roles in separating luminal B and HER2 + breast cancer subtypes.

Understanding the role of individual units in a deep neural network.

Deep neural networks excel at finding hierarchical representations that solve complex tasks over large datasets. How can we humans understand these learned representations? In this work, we present network dissection, an analytic framework to systematically identify the semantics of individual hidden units within image classification and image generation networks. First, we analyze a convolutional neural network (CNN) trained on scene classification and discover units that match a diverse set of object concepts. We find evidence that the network has learned many object classes that play crucial roles in classifying scene classes. Second, we use a similar analytic method to analyze a generative adversarial network (GAN) model trained to generate scenes. By analyzing changes made when small sets of units are activated or deactivated, we find that objects can be added and removed from the output scenes while adapting to the context. Finally, we apply our analytic framework to understanding adversarial attacks and to semantic image editing.

Complete genome sequence of a new badnavirus infecting a tea plant in China.

The complete genome of a novel virus, provisionally named "Camellia sinensis badnavirus 1" (CSBV1), was identified in tea plant (Camellia sinensis) leaves collected in Anhui Province, China. The genome of CSBV1 consists of 8,195 bp and possesses three open reading frames (ORFs), sharing 68.6 % nucleotide sequence identity with the genome of Camellia lemon glow virus (CLGV) from Camellia japonica. The genome organization of CSBV1 is highly similar to that of members of the genus Badnavirus (family Caulimoviridae). Phylogenetic analysis revealed that CSBV1, CLGV, and cacao swollen shoot virus form a separate clade within the genus Badnavirus, suggesting that CSBV1 is the first badnavirus infecting C. sinensis.

Screening high-risk population of persistent postpartum hypertension in women with preeclampsia using latent class cluster analysis.

BACKGROUND: A significant proportion of women with preeclampsia (PE) exhibit persistent postpartum hypertension (PHTN) at 3 months postpartum associated with cardiovascular morbidity. This study aimed to screen patients with PE to identify the high-risk population with persistent PHTN. METHODS: This retrospective cohort study enrolled 1,000 PE patients with complete parturient and postpartum blood pressure (BP) profiles at 3 months postpartum. The enrolled patients exhibited new-onset hypertension after 20 weeks of pregnancy, while those with PE superimposed upon chronic hypertension were excluded. Latent class cluster analysis (LCCA), a method of unsupervised learning in machine learning, was performed to ascertain maternal exposure clusters from eight variables and 35 subordinate risk factors. Logistic regression was applied to calculate odds ratios (OR) indicating the association between clusters and PHTN. RESULTS: The 1,000 participants were classified into three exposure clusters (subpopulations with similar characteristics) according to persistent PHTN development: high-risk cluster (31.2%), medium-risk cluster (36.8%), and low-risk cluster (32.0%). Among the 1,000 PE patients, a total of 134 (13.4%) were diagnosed with persistent PHTN, while the percentages of persistent PHTN were24.68%, 10.05%, and 6.25% in the high-, medium-, and low-risk clusters, respectively. Persistent PHTN in the high-risk cluster was nearly five times higher (OR, 4.915; 95% confidence interval (CI), 2.92-8.27) and three times (OR, 2.931; 95% CI, 1.91-4.49) than in the low- and medium-risk clusters, respectively. Persistent PHTN did not differ between the medium- and low-risk clusters. Subjects in the high-risk cluster were older and showed higher BP, poorer prenatal organ function, more adverse pregnancy events, and greater medication requirement than the other two groups. CONCLUSION: Patients with PE can be classified into high-, medium-, and low-risk clusters according to persistent PHTN severity; each cluster has cognizable clinical features. This study's findings stress the importance of controlling persistent PHTN to prevent future cardiovascular disease.

CsLAZY1 mediates shoot gravitropism and branch angle in tea plants (Camellia sinensis).

BACKGROUND: Branch angle is a pivotal component of tea plant architecture. Tea plant architecture not only affects tea quality and yield but also influences the efficiency of automatic tea plant pruning. However, the molecular mechanism controlling the branch angle, which is an important aspect of plant architecture, is poorly understood in tea plants. RESULTS: In the present study, three CsLAZY genes were identified from tea plant genome data through sequence homology analysis. Phylogenetic tree displayed that the CsLAZY genes had high sequence similarity with LAZY genes from other plant species, especially those in woody plants. The expression patterns of the three CsLAZYs were surveyed in eight tissues. We further verified the expression levels of the key CsLAZY1 transcript in different tissues among eight tea cultivars and found that CsLAZY1 was highly expressed in stem. Subcellular localization analysis showed that the CsLAZY1 protein was localized in the plasma membrane. CsLAZY1 was transferred into Arabidopsis thaliana to investigate its potential role in regulating shoot development. Remarkably, the CsLAZY1 overexpressed plants responded more effectively than the wild-type plants to a gravity inversion treatment under light and dark conditions. The results indicate that CsLAZY1 plays an important role in regulating shoot gravitropism in tea plants. CONCLUSIONS: The results provide important evidence for understanding the functions of CsLAZY1 in regulating shoot gravitropism and influencing the stem branch angle in tea plants. This report identifies CsLAZY1 as a promising gene resource for the improvement of tea plant architecture.

Phosphine-Catalyzed Synthesis of 3-Allyl-4-pyrones by the Tandem Reaction of Diynones and Allylic Alcohols.

A simple and effective tandem reaction of diynones and allylic alcohols was developed to afford functionalized 3-allyl-4-pyrones in moderate to excellent yields. This protocol underwent a Michael addition─Claisen rearrangement─O-cyclization process, which exhibited broad substrate tolerance, high regioselectivity, and atom economy under a metal-free condition. Moreover, functional transformation of the products was also further studied.

Catalyst- and Additive-Free Annulation of Ynediones and (Iso)Quinoline N-Oxides: An Approach to Synthesis of Pyrrolo[2,1-a]Isoquinolines and Pyrrolo[1,2-a]Quinolines.

A simple and effective annulation of ynediones and (iso)quinoline N-oxides was developed to afford various functionalized pyrrolo[2,1-a]isoquinolines and pyrrolo[1,2-a]quinolines in moderate to excellent yields. This protocol underwent a tandem [3 + 2] cycloaddition/ring-opening/N-nucleophilic addition, which exhibited high regioselectivity, broad substrate tolerance, and atom economy under catalyst-, additive-free, and air conditions. Moreover, indolizine was also successfully prepared using pyridine N-oxide.

Transcriptomic analyses reveal a systemic defense role of the uninfested adjacent leaf in tea plant (Camellia sinensis) attacked by tea geometrids (Ectropis obliqua).

To get a more detailed understanding of the interaction between tea plant (Camellia sinensis) and tea geometrids (Ectropis obliqua), transcriptomic profile in undamaged adjacent leaf (TGL) of tea geometrids fed local leaves (LL) was investigated for the first time. Here, approximately 245 million clean reads contained 39.39 Gb of sequence data were obtained from TGL. Further analysis revealed that systemic response was induced in TGL after tea geometrids feeding on LL, although the defense response was weaker than that in LL. The differentially expressed genes (DEGs) identification analysis showed little overlap of DEGs between TGL and LL. Comparative transcriptome analysis suggested that JA signal regulated resistant pathway was induced in LL; whereas primary metabolism pathway was activated in TGL in response to tea geometrids feeding. This study reveals a novel resistance mechanism of TGL to tea geometrids feeding.

Comprehensive profiling of alternative splicing landscape during cold acclimation in tea plant.

BACKGROUND: Alternative splicing (AS) may generate multiple mRNA splicing isoforms from a single mRNA precursor using different splicing sites, leading to enhanced diversity of transcripts and proteins. AS has been implicated in cold acclimation by affecting gene expression in various ways, yet little information is known about how AS influences cold responses in tea plant (Camellia sinensis). RESULTS: In this study, the AS transcriptional landscape was characterized in the tea plant genome using high-throughput RNA-seq during cold acclimation. We found that more than 41% (14,103) of genes underwent AS events. We summarize the possible existence of 11 types of AS events, including the four common types of intron retention (IR), exon skipping (ES), alternative 5' splice site (A5SS), and alternative 3' splice site (A3SS); of these, IR was the major type in all samples. The number of AS events increased rapidly during cold treatment, but decreased significantly following de-acclimation (DA). It is notable that the number of differential AS genes gradually increased during cold acclimation, and these genes were enriched in pathways relating to oxidoreductase activity and sugar metabolism during acclimation and de-acclimation. Remarkably, the AS isoforms of bHLH transcription factors showed higher expression levels than their full-length ones during cold acclimation. Interestingly, the expression pattern of some AS transcripts of raffinose and sucrose synthase genes were significantly correlated with sugar contents. CONCLUSION: Our findings demonstrated that changes in AS numbers and transcript expression may contribute to rapid changes in gene expression and metabolite profile during cold acclimation, suggesting that AS events play an important regulatory role in response to cold acclimation in tea plant.

Evaluation of the anti-Thomsen-Friedenreich antibodies Nemod-TF1 and Nemod-TF2 as prognostic markers in breast cancer.

PURPOSE: The TF (Thomsen-Friedenreich, CD176, Galß1-3GalNAc) carbohydrate moiety is known as a specific oncofetal carbohydrate epitope present in fetal and neoplastic tissue as well as in stem cells. TF was demonstrated to mediate tumor-promoting features and to be highly immunogenic. The current study aimed to evaluate whether presence of the TF antigen is associated with clinico-pathological parameters and prognosis of early breast cancer (BC). METHODS: Primary BC tissue (n = 226) was stained for TF using two monoclonal anti-TF antibodies (Nemod-TF1, Nemod-TF2). Staining results were correlated to clinical data including survival. RESULTS: Nemod-TF1 staining was positively correlated to lymph node metastasis (p = 0.03) and the presence of tumor-associated MUC1 (TA-MUC1; p = 0.003). Further, the presence of the Nemod-TF1 epitope predicted worse prognosis in TA-MUC1 positive (overall survival: p = 0.026) as well as in triple negative (overall survival: p = 0.002; distant metastasis-free survival: p = 0.012) BC. CONCLUSIONS: The data presented here further support a role of TF in BC tumor biology. Whether anti-TF directed treatment approaches may gain clinical relevance in those cases determined as triple negative or TA-MUC1 positive remains to be determined.

Reversible Ligand-Gated Ion Channel via Interconversion between Hollow Single Helix and Intertwined Double Helix.

Ligand responsiveness is one of the typical mechanisms in biological organization to trigger sophisticated channel switching. Here, we report a new type of helical trimer which can undergo transition between a hollow single helix and an intertwined double helix with no cavity by complexation and decomplexation of Cu ions. In addition, the one dimensional (1D) hollow helical tubes spontaneously generated from single helices via π-π interactions embedded into the lipid bilayers and displayed satisfactory channel stability and efficiency. With the addition of CuI ions and further extraction with ammonia, the disassembly and reassembly of 1D hollow helical tubes gave rise to the reversible switching of channel activity in situ inside the bilayers. The synthetic helical system provides the first model of reversible ligand-gated ion channel by means of dynamic transition between single and double helices, which will be available for developing intelligent artificial nanochannels for potential biological and medicinal applications.

Synthesis of 1-Cyano-3-acylnaphthalenes via Formal [4+2] Benzannulation of 2-(2-Alkynylphenyl)acetonitriles and Alkynones.

Effective transition-metal-free formal [4+2] benzannulation for the preparation of 1-cyano-3-acylnaphthalenes from 2-(2-alkynylphenyl)acetonitriles and alkynones through sequential C-C bond coupling has been developed. This protocol is characterized by mild conditions, excellent functional group tolerance, complete regioselectivity, and atom economy. The plausible mechanism, gram-scale synthesis, and further transformations of the product were studied.

Rapid and simultaneous analysis of tetrabromobisphenol A and hexabromocyclododecane in water by direct immersion solid phase microextraction: Uniform design to explore factors.

Direct immersion solid phase microextraction (DI-SPME) coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) is of significant research interest because of its low solvent consumption, simple design, and efficient, sensitive, fast performance. In this work, a combination of these two methods (DI-SPME-LC-MS) for the determination of tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD) in water was developed. Important factors, which included temperature, stirring rate, salt concentration, pH value and adsorption time, were evaluated in for the optimization of solid phase microextraction (SPME) method. The method was developed using spiked natural waters in a concentration range of 0.1-10 ng mL-1, and showed notable linearity with regression coefficients ranging between 0.992 and 0.999. The limits of detection varied from 0.01 to 0.04 ng mL-1 (at S/N = 3) and relative standard deviation (RSD < 11%) were obtained showing that the precision of the method was reliable. Recoveries were in relatively high levels for both analytes and ranged from 88% to 108%. Moreover, in comparison with the performance time of traditional sample pretreatment methods such as solid-phase extraction (SPE), accelerated solvent extraction (ASE), and liquid-liquid extraction (LLE), DI-SPME-LC-MS takes only approximately 35 min to perform. The optimized method was successfully applied for monitoring concentrations of TBBPA and HBCD in water.