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Silica sol is a high-performance nanomaterial widely used, and its synthesis methods mainly include ion exchange method, electrolytic electrodialysis method, dispersion method, etc. However, the performance of silica sol synthesized by different methods varies. In order to improve its drawbacks, it is often necessary to modify the silica sol, and common modification methods are mainly divided into physical modification and chemical modification. In this article, the synthesis methods, modification methods, and modified properties of silica sol were summarized, and its application in the field of wood was examined. The focus is on the relevant research on improving the mechanical properties and flame retardancy of wood. Finally, the development of silica sol in the field of wood was discussed. [ABSTRACT FROM AUTHOR]

Satellite‐to‐ground quantum communication constitutes the cornerstone of the global quantum network, heralding the advent of the future of quantum information. Continuous‐variable quantum key distribution is a strong candidate for the space‐ground quantum communication due to its simplicity, stability, and ease of implementation, especially for the robustness of space background light noise. Recently, the discrete‐modulated continuous‐variable protocol has garnered increased attention, owing to its lower implementation requirements, acceptable security key rate, and pronounced compatibility with extant infrastructures. Here, key rates are derived for discrete‐modulated continuous‐variable quantum key distribution protocols in free‐space channel environments across various conditions through numerical simulation, revealing the viability of its application in satellite‐to‐ground communication. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The azepine ring is a prominent structural scaffold in biologically significant molecules. In this study, we present a Ni(II)‐catalyzed asymmetric difunctionalization of alkynes, involving intermolecular regioselective arylation and intramolecular nitrile addition, enabling the synthesis of enantioenriched azepine derivatives. This reaction simultaneously installs an all‐carbon quaternary stereocenter and introduces an unprotected imine functionality, showing great promise for subsequent transformations. The reaction exhibits good tolerance toward various functional groups, resulting in high yields and enantioselectivities. The synthetic utility of this methodology is further demonstrated through gram‐scale synthesis and product derivatization. This research offers an efficient approach to the synthesis of seven‐membered nitrogen heterocycles. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Construction of axially chiral 1-azafluorenes via nickel-catalyzed [2+2+2] cycloaddition of alkynes and (o-alkynyl)benzyl nitriles is described. This strategy enables enantioselective discrimination of two sterically similar ortho substituents, such as H and F, during the construction of tri-ortho-substituted biaryl atropisomers. Mechanistic studies including the stereochemistry model and the stability of the atropenantiomers toward racemization are provided. The unique steric hindrance provided by 1-azafluorene skeleton and the fine chiral cavity of the nickel catalyst are key to achieving high enantioselectivity. [ABSTRACT FROM AUTHOR]

Spiking neural network (SNN) has attracted much attention due to its spatial–temporal information processing ability and high biological reliability. SNN is a hardware-friendly model based on event-driven and sparse triggering, which can achieve low power consumption and efficient information processing on neural morphological chips. However, SNN processes discrete spike trains, and its unique working mode makes it more difficult to train than traditional networks. Based on this, this paper proposes a spatiotemporal backpropagation (STBP) algorithm for directly training high-performance SNN. By narrowing the coding time window, we convert the leaky integrate-and-fire (LIF) into its explicit iterative version for direct SNN training. To solve the problem of non-differentiability of SNN discrete spikes, we introduce an approximate derivative of spike firing for gradient descent training. We propose a biologically reasonable channel reward (CR) mechanism integrated into the STBP algorithm. This method makes full use of the spatial domain (SD) and time domain (TD) information of input and does not require any additional complex techniques. We evaluate the proposed algorithm on traditional static MNIST, Fashion-MNIST datasets, and neuromorphological N-MNIST, DVS128 Gesture datasets. The experimental results show that the accuracy of this method in static and neuromorphological datasets exceeds the current advanced methods, and the time window used is small. This work provides a new perspective for directly training high-performance SNN. [ABSTRACT FROM AUTHOR]

A series of triangular nanorings, denoted BnN3–n-CPLY3 (n = 0, 1, 2, and 3), are designed by incorporating boron-/nitrogen-doped phenalenyl (B/N-PLY) units into cycloparaphenylene. These nanorings exhibit appropriate cavity size and shape complementarity to encapsulate fullerene (C60), resulting in the formation of supramolecular complexes termed BnN3–n-CPLY3@C60 (n = 0, 1, 2, 3). The geometric and electronic structures of nanorings and supramolecular complexes are investigated by density functional theory. Importantly, the self-assembly strategy effectively enhances the second-order nonlinear optical (NLO) response of the supramolecular complexes. The findings demonstrate that the first hyperpolarizabilities of BnN3–n-CPLY3@C60 (n = 0, 1, 2) are higher compared to that of B3-CPLY3@C60, which is attributed to the intra- and intermolecular charge transfer (CT) regulated by adjusting the amount of the B/N-PLY unit. By absorption spectrum analysis, the absorption peaks of BnN3–n-CPLY3@C60 (n = 0, 1, 2) are attributed to the host–guest interaction between BnN3–n-CPLY3 and C60. Furthermore, CT spectroscopy, main electron transition, and CT properties are studied to gain insights into the optical properties of BnN3–n-CPLY3@C60. This work not only emphasizes the importance of the B/N-PLY unit in supramolecular complexes to improve NLO properties but also shows that the BnN3–n-CPLY3@C60 complexes are important materials for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Spiking neural network (SNN) is a new generation of artificial neural networks (ANNs), which is more analogous with the brain. It has been widely considered with neural computing and brain-like intelligence. SNN is a sparse trigger event-driven model, and it has the characteristics of hardware friendliness and energy saving. SNN is more suitable for hardware implementation and rapid information processing. SNN is also a powerful method for deep learning (DL) to study brain-like computing. In this paper, the common SNN learning and training methods in the field of image classification are reviewed. In detail, we examine the SNN algorithms based on synaptic plasticity, approximate backpropagation (BP), and ANN to SNN. This paper comprehensively introduces and tracks the latest progress of SNN. On this basis, we also analyze and discuss the challenges and opportunities it faces. Finally, this paper prospects for the future development of SNN in the aspects of the biological mechanism, network training and design, computing platform, and interdisciplinary communication. This review can provide a reference for the research of SNN to promote its application in complex tasks. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quantum secret sharing (QSS) is one of the basic communication primitives in future quantum networks which addresses part of the basic cryptographic tasks of multiparty communication and computation. Nevertheless, it is a challenge to provide a practical QSS protocol with security against general attacks. A QSS protocol that balances security and practicality is still lacking. Here, we propose a QSS protocol with simple phase encoding of coherent states among three parties. Removing the requirement of impractical entangled resources and the need for phase randomization, our protocol can be implemented with accessible technology. We provide the finite-key analysis against coherent attacks and implement a proof-of-principle experiment to demonstrate our scheme’s feasibility. Our scheme achieves a key rate of 85.3 bps under a 35 dB channel loss. Combined with security against general attacks and accessible technology, our protocol is a promising candidate for practical multiparty quantum communication networks. [ABSTRACT FROM AUTHOR]

Quantum conference key agreement is an important cryptographic primitive for future quantum network. Realizing this primitive requires high-brightness and robust multiphoton entanglement sources, which is challenging in experiment and unpractical in application because of limited transmission distance caused by channel loss. Here we report a measurement-device-independent quantum conference key agreement protocol with enhanced transmission efficiency over lossy channel. With spatial multiplexing nature and adaptive operation, our protocol can break key rate bounds on quantum communication over quantum network without quantum memory. Compared with previous work, our protocol shows superiority in key rate and transmission distance within the state-of-the-art technology. Furthermore, we analyse the security of our protocol in the composable framework and evaluate its performance in the finite-size regime to show practicality. Based on our results, we anticipate that our protocol will play an important role in constructing multipartite quantum network. Realizing quantum conference key agreement is challenging in experiment and unpractical in application because of limited transmission distance caused by channel loss. The authors present here a quantum conference key agreement protocol with spatial multiplexing nature and adaptive operation, which can break limitations on quantum communication over network and thus shed some light on future global quantum network. [ABSTRACT FROM AUTHOR]

Swim bladder polypeptides (SBPs) of Acipenser schrencki were analyzed for their antioxidant activity and physicochemical properties. The results showed the optimal enzymatic conditions were alkaline protease with a solid-to-liquid ratio of 1:20, an incubation time of 4 h, a temperature of 55 °C, and an enzyme dosage of 5000 U/g. Three different molecular weight fractions (F1, F2, and F3) were obtained via ultrafiltration. F3 (912.44–2135.82 Da) showed 77.90%, 72.15%, and 66.25% removal of O2•-, DPPH•, and •OH, respectively, at 10 mg/mL, which was significantly higher than the F1 and F2 fractions (p < 0.05). F3 contained proline (6.17%), hydroxyproline (5.28%), and hydrophobic amino acids (51.39%). The UV spectrum of F3 showed maximum absorption at 224 nm. Peptide sequence analysis showed that F3 contained antioxidant peptides (MFGF, GPPGPRGPPGL, and GPGPSGERGPPGPM) and exhibited inhibitory activities on angiotensin-converting enzyme and dipeptidyl peptidase III/IV (FRF, FPFL and LPGLF). F3 was considered a good raw material for obtaining bioactive peptides. [ABSTRACT FROM AUTHOR]

Carbon nanohoop compounds have attracted extensive attention recently due to their aesthetically pleasing structures and unique properties. In order to reveal the structure–property relationship between the size-dependent effect and the nonlinear optical (NLO) response, a series of carbon nanohoops consisting of zigzag carbon nanotubes (CNTs), named D-CM2PnP-A (n = 4, 6, 8, 10, and 12), are systematically designed and investigated using density functional theory (DFT). Significantly, the first hyperpolarizability (βtot) of the system increases with the increasing structure size, which is primarily the result of the charge transfer transition. Subsequently, the major electronic transition changes from local excitation to charge transfer as the size of the structure increases, indicating that charge transfer becomes stronger significantly. Furthermore, a two-level model and the absorption spectrum can well explain the trend of the βtot value. In addition, the unit sphere representation (USR) and hyper-Rayleigh scattering (HRS) are used to further explain the nature of the second-order NLO response. More importantly, adding a π-bridge as an effective strategy further enhances the second-order NLO responses of the system. The relevant results are expected to provide a new perspective on the structure–NLO property correlation of donor (D)–conjugated bridge (π)–acceptor (A) type carbon nanohoops and theoretical guidance for the rational design and synthesis of fascinating carbon nanohoops as NLO materials. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed synthesis of enantiopure [1,1′-binaphthalene]-2,2′-dicarbonitriles from BINOL-bistriflates and zinc cyanide is reported. This cross-coupling reaction employs a 0.1–5 mol% catalyst loading, and is scalable and stereospecific. The synthetic applications of this reaction are demonstrated by product derivatizations and the synthesis of [1,1′-binaphthalene]-2,2′-bisoxazolines (BOXAX). [ABSTRACT FROM AUTHOR]

Numerical methods are widely used to calculate the secure key rate of many quantum key distribution protocols in practice, but they consume many computing resources and are too time-consuming. In this work, we take the homodyne detection discrete-modulated continuous-variable quantum key distribution (CV-QKD) as an example, and construct a neural network that can quickly predict the secure key rate based on the experimental parameters and experimental results. Compared to traditional numerical methods, the speed of the neural network is improved by several orders of magnitude. Importantly, the predicted key rates are not only highly accurate but also highly likely to be secure. This allows the secure key rate of discrete-modulated CV-QKD to be extracted in real time on a low-power platform. Furthermore, our method is versatile and can be extended to quickly calculate the complex secure key rates of various other unstructured quantum key distribution protocols. [ABSTRACT FROM AUTHOR]

Spiking neural network (SNN) is one of the most successful methods to imitate biological brain behavior and learning potential. The information processing mechanism of SNN combines the concepts of time and space. To address the performance dropping problem during the conversion process from the artificial neural network (ANN) to SNN, this paper proposes a proportional attenuation leaky integrate-and-fire (RA-LIF) neuron model to solve the problem of membrane potential loss caused by leaky integrate-and-fire (LIF) neurons. The accuracy of the SNN network based on RA-LIF neurons on MNIST is 98.76%. This paper also proposes a weight normalization method to help adjust the network spiking rate to reduce the loss. We evaluate and analyze the performance of SNN networks based on LIF, RA-LIF, and AD-LIF. By analyzing the spike firing rate and convergence rate, the effects of spike frequency and neuron threshold on the performance of the network are discussed. So far, the SNN transformed by ANN can only achieve worse or similar performance compared with the original network. For the first time, the performance of the SNN transformed by the proposed RA-LIF neuron model and weight normalization method is better than the original network, which shows the test accuracy of 98.88% on MNIST. The SNN obtained by converting the LeNet network using the above method achieves a test accuracy of 98.91% on MNIST. In conclusion, the RA-LIF neuron model and normalization method proposed in this paper have promising applicability. Moreover, this method has the characteristics of high precision and fast calculation speed, which can provide a reference for the research of the SNN framework. [ABSTRACT FROM AUTHOR]

A highly enantioselective NiH‐catalyzed hydrocyclization of alkynones with unparalleled anti‐ and endocyclic selectivities is described. The choice of the precatalysts has significant influence in tuning the regio‐ and enantioselectivity. Using Ni(OTs)2/Phox as a precatalyst and (EtO)2MeSiH as a hydride source, an array of enantioenriched O‐, N‐, and S‐containing heterocyclic tertiary allylic alcohols are obtained in 24–81 % yields with 80:20–99:1 er. Mechanistic investigations and synthetic application are also carried out. This study represents an efficient access to a set of allylic alcohols that are unable to access by the state‐of‐the‐art coupling reactions. [ABSTRACT FROM AUTHOR]

A highly enantioselective NiH‐catalyzed hydrocyclization of alkynones with unparalleled anti‐ and endocyclic selectivities is described. The choice of the precatalysts has significant influence in tuning the regio‐ and enantioselectivity. Using Ni(OTs)2/Phox as a precatalyst and (EtO)2MeSiH as a hydride source, an array of enantioenriched O‐, N‐, and S‐containing heterocyclic tertiary allylic alcohols are obtained in 24–81 % yields with 80:20–99:1 er. Mechanistic investigations and synthetic application are also carried out. This study represents an efficient access to a set of allylic alcohols that are unable to access by the state‐of‐the‐art coupling reactions. [ABSTRACT FROM AUTHOR]

Gene expression data has the characteristics of high dimensionality and a small sample size and contains a large number of redundant genes unrelated to a disease. The direct application of machine learning to classify this type of data will not only incur a great time cost but will also sometimes fail to improved classification performance. To counter this problem, this paper proposes a dimension-reduction algorithm based on weighted kernel principal component analysis (WKPCA), constructs kernel function weights according to kernel matrix eigenvalues, and combines multiple kernel functions to reduce the feature dimensions. To further improve the dimensional reduction efficiency of WKPCA, t-class kernel functions are constructed, and corresponding theoretical proofs are given. Moreover, the cumulative optimal performance rate is constructed to measure the overall performance of WKPCA combined with machine learning algorithms. Naive Bayes, K-nearest neighbour, random forest, iterative random forest and support vector machine approaches are used in classifiers to analyse 6 real gene expression dataset. Compared with the all-variable model, linear principal component dimension reduction and single kernel function dimension reduction, the results show that the classification performance of the 5 machine learning methods mentioned above can be improved effectively by WKPCA dimension reduction. [ABSTRACT FROM AUTHOR]

Numerous antitumor drugs exhibited excellent anti-proliferation activities, discovered from natural products. Oridonin is isolated from a traditional Chinese medicine Isodon rubescens, and it exhibit various biological functions including anticancer, anti-inflammation, antibacterial, and so on. The anticancer mechanisms of oridonin include apoptosis, autophagy, cell cycle arrest, and so on. However, clinical research and application of oridonin has been hampered, due to the poor pharmaceutical property. So many studies on oridonin have been explored in the purpose of improve the pharmaceutical property, including investigation of the mechanism of action in depth and structural modification. In this review, we summarized oridonin and oridonin derivatives as potential anticancer agents, and detailed discussion on biological properties, mechanism of actions and potential for overcoming therapeutic resistance. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Main observation and conclusion: A redox‐neutral Fe‐catalyzed intramolecular C—H amidation of N‐benzoyloxyureas is described. This methodology employs a simple iron complex in situ generated from Fe(OTf)2 and bipyridine as the catalyst and N‐benzoyloxyureas as the nitrene precursors without using exogenous oxidants. An array of cyclic ureas were synthesized via aliphatic C(sp3)—H amidation in excellent yields. In addition, this catalytic system is also amenable to aryl C(sp2)—H nitrene insertion to provide benzimidazolones in moderate yields. [ABSTRACT FROM AUTHOR]

Introduction: Perampanel is a highly selective and noncompetitive α‐amino‐3 ‐hydroxy‐5‐methyl‐4‐isoxazole propionate receptor (AMPAR) antagonist, which has been used as an orally administered antiepileptic drug in more than 55 countries. Recently, perampanel was shown to exert neuroprotective effects in hemorrhagic and ischemic stroke models via regulating blood–brain barrier (BBB) function. Aim: Here, the protective effects of perampanel were investigated in an in vitro neurovascular unit (NVU) system established using a triple cell co‐culture model (neurons, astrocytes, and brain microvascular endothelial cells) and in an in vivo traumatic brain injury (TBI) model. Results: Neurons in the NVU system exhibit a more mature morphological phenotype compared with neurons cultured alone, and the co‐culture system mimicked an impermeable barrier in vitro. Perampanel protects the NVU system against traumatic and excitotoxic injury, as evidenced by reduced lactate dehydrogenase (LDH) release and apoptotic rate. Treatment with perampanel attenuated lipid peroxidation and expression of inflammatory cytokines. In addition, perampanel increased Sirt3 protein expression, enhanced the activities of mitochondrial enzyme IDH2 and SOD2, and preserved BBB function in vitro. Knockdown of Sirt3 using specific siRNA (Si‐Sirt3) partially reserved the effects of perampanel on neuronal injury and BBB function. Treatment with perampanel in vivo attenuated brain edema, preserved neurological function, inhibited apoptosis and microglia activation after TBI. Furthermore, perampanel increased the expression of Sirt3 and preserved BBB function after TBI. The effect of perampanel on BBB function and brain edema was abolished by knockdown of Sirt3 in vivo. Conclusion: Our results indicate that the noncompetitive AMPAR antagonist perampanel protects the NVU system and reduces brain damage after TBI via activating the Sirt3 cascades. [ABSTRACT FROM AUTHOR]

Germ cells are vital for reproduction and heredity. However, the mechanisms underlying female germ cell development in primates, especially in late embryonic stages, remain elusive. Here, we performed single-cell RNA sequencing of 12,471 cells from whole fetal ovaries, and explored the communications between germ cells and niche cells. We depicted the two waves of oogenesis at single-cell resolution and demonstrated that progenitor theca cells exhibit similar characteristics to Leydig cells in fetal monkey ovaries. Notably, we found that ZGLP1 displays differentially expressed patterns between mouse and monkey, which is not overlapped with NANOG in monkey germ cells, suggesting its role in meiosis entry but not in activating oogenic program in primates. Furthermore, the majority of germ cell clusters that sharply express PRDM9 and SPO11 might undergo apoptosis after cyst breakdown, leading to germ cell attrition. Overall, our work provides new insights into the molecular and cellular basis of primate fetal ovary development at single-cell resolution. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: The direct amination of unactivated primary C—H bonds is extremely challenging due to their inert nature. Herein, we report an intramolecular primary C—H amination of sulfamate esters using an iron catalyst derived from iron(II) triflate and bipyridine. An array of oxathiazinanes were synthesized in moderate to good yields, which were further converted into biologically important azetidines by a one‐pot procedure. This research demonstrates the potential of applying simple nitrogen ligands in iron‐catalyzed C—H functionalization and offers an accessible alternative to state‐of‐the‐art iron‐nitrene chemistry. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed arylation/aza-Michael addition cascade reaction of β-substituted cyclic enones and 2-haloanilines has been reported. Using 1 mol% Pd(PPh3)4 as a catalyst, C2-spiroindolines are accessed via an intermolecular vinylogous arylation of β-alkyl cyclic enones and 2-haloanilines followed by an intramolecular aza-Michael addition. The functional group tolerance of this transformation is examined by 18 examples in up to 93% yield. In the second part, we developed an α′-arylation/aza-Michael addition cascade strategy to construct azabicyclo[3.2.2]nonanones catalyzed by Pd(MeCN)2Cl2·PPh3. This study provides a quick route to complex and useful spiro- and bridged-heterocycles from readily available starting materials in good yields with high regioselectivity. [ABSTRACT FROM AUTHOR]

Tetrahydrocarbazol‐4‐one represents a prevalent framework of numerous natural products and pharmaceuticals. This review summaries the recent synthetic progresses of this core structure, including Fischer indolization, oxidative and reductive coupling, α‐arylative cyclization by means of transition‐ metal catalysis or under metal‐free conditions, and other methods. The recently emerged enantioselective catalytic methods of tetrahydrocarbazol‐4‐ ones are also described. The mechanistic insights and applications of these strategies as a key step in the total (formal) synthesis of complex alkaloids are highlighted as well. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed intramolecular α‐arylation and defluorinative aromatization strategy for the synthesis of polysubstituted 2‐naphthols is reported. With ortho‐bromobenzyl‐substituted α‐fluoroketones as the substrates and palladium acetate/triphenylphosphine as the catalyst, this method features good functional group tolerance, readily available catalyst and starting materials, and high yields. The applications of the strategy are demonstrated by the synthesis of useful building blocks, such as naphtha[2,3‐b]furan, naphthol AS‐D, and ligands/catalysts. [ABSTRACT FROM AUTHOR]

Gastric cancer (GC) is one of the most common malignant tumors worldwide. Previous studies have reported that aldehyde dehydrogenase-1A1 (ALDH1A1) and cluster of differentiation (CD)-133 are considered to be cancer stem cell markers in GCs. The present study immunohistochemically examined the distribution and expression of two tumor stem cell markers, CD133 and ALDH1A1, in both primary tumors and para-tumor tissues. In 91 cases with stage III, 57 (62%) were positive for ALDH1A1 and 60 (66%) were positive for CD133. ALDH1A1 was detected in para-tumors and cancerous tissues of the stomach, and the immunoreactivity of the tumors was stronger than that in para-tumor tissues. CD133 was only detected in tumors. The expression of ALDH1A1 was significantly associated with advanced T/N stage (T stage, P=0.012; N stage, P=0.023) and poor differentiation (P=0.020), while CD133 was associated with advanced T stage (P=0.007). Univariate and multivariate Cox proportional hazards analysis revealed that tumor stage, CD133 expression, vascular invasion and sex were independent predictors of disease-free survival (DFS) time, and tumor size, vascular invasion and sex were independent predictors of overall survival (OS) time in patients with GC. Patients with CD133+ GC had poorer DFS (P=0.042), while ALDH1A1+ GC was not associated with poorer DFS. In regard to chemotherapy, improvements in survival were not observed after the addition of taxane compared with two-drug therapy. However, the subgroup analysis indicated that in the ALDH1A1− subgroup, and CD133+ and ALDH1A1− subgroups, an increased OS was observed in two-drug therapy (P=0.043). The results of the present study indicate that ALDH1A1 and CD133 may play an important role in tumor invasion, metastasis and prognosis, and ALDH1A1− expression does not benefit the taxane-based triple chemotherapeutic regimen in patients with GC. [ABSTRACT FROM AUTHOR]

Deuterated compounds are of great importance in chemistry and pharmaceuticals. Reductive dehalogenation is one of the most useful methods to incorporate deuterium into molecules. This article briefly discusses the historical development of dehalogenative deuteration reactions that involve transition-metal catalysis, radical halogen abstraction, alkali-metal reductive deuteration, and the recently developed potassium methoxide/hexamethyldisilane-mediated dehalogenation of aryl halides. [ABSTRACT FROM AUTHOR]

Recent advances in the use of silicon-tethered frameworks as directing groups for the efficient construction of C–C, C–B, C–O and C–X (X = halogen) bonds are discussed in this short review. In addition, mechanistic insights are briefly discussed. Hence, the goal of this short review is to give an overview of the state of the art in this field, encompassing the reactivity, selectivity and efficiency of different processes. 1 Introduction 2 Carbon–Carbon Bond Formation 2.1 Alkenylation 2.2 Arylation 2.3 Carbonylation 3 Carbon–Boron Bond Formation 4 Carbon–Oxygen and Carbon–Halogen Bond Formation 5 Conclusion [ABSTRACT FROM AUTHOR]

Colletotrichum gloeosporioides is the causal agent of rubber anthracnose, which is also one of the important biological factors threatening the development of natural rubber industry in the world. Regulators of G-protein signaling (RGS) are key negative regulators of G-proteins, which play important roles in growth, development and pathogenic processes of plant pathogens. In this study, a RGS gene CgRGS1 was functionally characterized in C. gloeosporioides. Compared to the wild type, the CgRGS1 deletion mutant had slow vegetative growth, reduced conidia with multi-end germination, low appressorium formation rate, high resistance to oxidative stress and SDS. Moreover, the mutant was sensitive to osmotic pressure and showed decreased virulence. In conclusion, CgRGS1 is involved in regulation of vegetative growth, conidiation, germination, appressorium formation, oxidative stress, osmotic pressure response and pathogenicity in C. gloeosporioides. [ABSTRACT FROM AUTHOR]

The first highly diastereo- and enantioselective synthesis of five-membered spiro-2 H-pyrroles was achieved using an Ir-catalyzed asymmetric allylic dearomatization reaction. The spiro-2 H-pyrrole derivatives readily undergo a controllable and stereospecific allylic migration under acid catalysis, providing polycyclic pyrrole derivatives in excellent yields and ee values. Additionally, the novel Ir-complex K1, derived from [Ir(cod)Cl]2 (cod=1,5-cyclooctadiene) and N-benzhydryl- N-phenyldinaphthophosphoramidite (BHPphos), showed excellent control of both diastereo- and enantioselectivities. [ABSTRACT FROM AUTHOR]

The first highly diastereo- and enantioselective synthesis of five-membered spiro-2 H-pyrroles was achieved using an Ir-catalyzed asymmetric allylic dearomatization reaction. The spiro-2 H-pyrrole derivatives readily undergo a controllable and stereospecific allylic migration under acid catalysis, providing polycyclic pyrrole derivatives in excellent yields and ee values. Additionally, the novel Ir-complex K1, derived from [Ir(cod)Cl]2 (cod=1,5-cyclooctadiene) and N-benzhydryl- N-phenyldinaphthophosphoramidite (BHPphos), showed excellent control of both diastereo- and enantioselectivities. [ABSTRACT FROM AUTHOR]

Heteroaromatic compounds containing carbon-silicon (C-Si) bonds are of great interest in the fields of organic electronics and photonics, drug discovery, nuclear medicine and complex molecule synthesis, because these compounds have very useful physicochemical properties. Many of the methods now used to construct heteroaromatic C-Si bonds involve stoichiometric reactions between heteroaryl organometallic species and silicon electrophiles or direct, transition-metal-catalysed intermolecular carbon-hydrogen (C-H) silylation using rhodium or iridium complexes in the presence of excess hydrogen acceptors. Both approaches are useful, but their limitations include functional group incompatibility, narrow scope of application, high cost and low availability of the catalysts, and unproven scalability. For this reason, a new and general catalytic approach to heteroaromatic C-Si bond construction that avoids such limitations is highly desirable. Here we report an example of cross-dehydrogenative heteroaromatic C-H functionalization catalysed by an Earth-abundant alkali metal species. We found that readily available and inexpensive potassium tert-butoxide catalyses the direct silylation of aromatic heterocycles with hydrosilanes, furnishing heteroarylsilanes in a single step. The silylation proceeds under mild conditions, in the absence of hydrogen acceptors, ligands or additives, and is scalable to greater than 100 grams under optionally solvent-free conditions. Substrate classes that are difficult to activate with precious metal catalysts are silylated in good yield and with excellent regioselectivity. The derived heteroarylsilane products readily engage in versatile transformations enabling new synthetic strategies for heteroaromatic elaboration, and are useful in their own right in pharmaceutical and materials science applications. [ABSTRACT FROM AUTHOR]

Owing to its unique function to release the progeny virus particles from the surface of an infected cell, neuraminidase has drawn special attention for developing new drugs to treat influenza viruses. The 150-cavity that is adjacent to the active pocket of the group-1 neuraminidase (N1) renders the conformational change from ‘open’ form to ‘closed’ form when enzyme is binding with a ligand. Consequently, it would be a better strategy to design multi-binding-site inhibitors including X and R groups with proper shapes, sizes and electronic charges fitting into the active site. The NCI and ZINC fragment databases were screened for finding the optimal fragments with de novo design technique. By doing so, 24 derivatives of oseltamivir were obtained by linking the fragments at two different sites of the scaffold of oseltamivir. Molecular docking and dynamics showed that these compounds not only adopt more favourable conformation but also have stronger binding interaction with receptor. Most importantly, all compounds skilfully pass through the cleft (formed by Glu119 and Arg156) and fit into 150-cavity. Therefore, the selected 24 derivatives may become promising candidates for treating influenza virus; in addition, the findings reported here may at least provide useful insights and stimulate new strategy in this area. [ABSTRACT FROM AUTHOR]

An ejector of low NO burner was designed for a gas instantaneous water heater in this work. The flowing and mixing process of the ejector was investigated by computational fluid dynamics (CFD) approach. A comprehensive study was conducted to understand the effects of the geometrical parameters on the static pressure of air and methane, and mole fraction uniformity of methane at the outlet of ejector. The distribution chamber was applied to balance the pressure and improve the mixing process of methane and air in front of the fire hole. A distribution orifice plate with seven distribution orifices was introduced at the outlet of the ejector to improve the flow organization. It is found that the nozzle exit position of 5 mm and nozzle diameter d >1.3 mm should be used to improve the flow organization and realize the well premixed combustion for this designed ejector. [ABSTRACT FROM AUTHOR]

Eeny, meeny, miny …︁ enaminones! Lactams and imides have been shown to consistently provide enantioselectivities substantially higher than other substrate classes previously investigated in the palladium‐catalyzed asymmetric decarboxylative allylic alkylation. Several new substrates have been designed to probe the contributions of electronic, steric, and stereoelectronic factors that distinguish the lactam/imide series as superior alkylation substrates (see scheme). These studies culminated in marked improvements on carbocyclic allylic alkylation substrates. [ABSTRACT FROM AUTHOR]