Nickel-Catalyzed Chemoselective Carbomagnesiation for Atroposelective Ring-Opening Difunctionalization.

There is a pressing need for methods that can connect enantioenriched organic compounds with readily accessible building blocks via asymmetric functionalization of unreactive chemical bonds in organic synthesis and medicinal chemistry. Herein, the asymmetric chemoselective cleavage of two unactivated C(Ar)-O bonds in the same molecule is disclosed for the first time through an unusual nickel-catalyzed carbomagnesiation. This reaction facilitates the evolution of a novel atroposelective ring-opening difunctionalization. Utilizing readily available dibenzo bicyclic substrates, diverse valuable axially chiral biaryls are furnished with high efficiencies. Synthetic elaborations showcase the application potential of this method. The features of this method include good atom-economy, multiple roles of the nucleophile, and a simple catalytic system that enables the precise magnesiation of an α-C(Ar)-O bond and arylation of a ß-C(Ar)-O bond.

Associations between human cytomegalovirus infection and type 2 diabetes mellitus: a systematic review and meta-analysis.

OBJECTIVE: Multiple studies have reported a potential contribution of human cytomegalovirus (HCMV) to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, the association between HCMV and type 2 diabetes mellitus (T2DM) remains unclear. In this paper, we employ the meta-analysis approach to investigate the potential correlation between HCMV infection and T2DM. METHOD: The data of our study were collected from PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure and WAN FANG databases from inception to November 2022. Using the Review Manager V.5.4 software, the meta-analysis was performed. RESULTS: A total of 18 139 patients from 22 studies were included in our analysis. In the Asian subgroup, the patients with T2DM group had a significantly higher frequency of HCMV infection and older age compared with the healthy group. In the European, the frequency of HCMV infection in the T2DM was lower than the healthy group, although this difference was not statistically significant. After adjusting for demographic factors, the adjusted OR of T2DM for risk of by HCMV status was not found to be significant (adjusted OR=1.19, 95% CI=0.88 to 1.62, p>0.05). Additionally, T2DM with vasculopathy had a significantly higher rate of HCMV infection compared with those without vasculopathy (OR=1.87, 95% CI=1.24 to 2.83, p<0.05). Among T2DM with HCMV infection, there were significant increases in fasting blood glucose levels and the proportion of CD8+ T lymphocytes. Conversely, fasting blood insulin levels, the proportion of CD4+ T lymphocyte and the CD4+/CD8+ ratio were significantly decreased compared with the healthy group. CONCLUSION: At present, the available evidence does not provide a clear understanding of whether there is a significant association between T2DM and HCMV infection. Additionally, T2DM with HCMV infection exhibited significantly worse blood glucose regulation and immune markers, as well as a higher frequency of vasculopathy. PROSPERO REGISTRATION NUMBER: CRD42022342066.

Nickel-Catalyzed Enantioconvergent Transformation of Anisole Derivatives via Cleavage of C-OMe Bond.

Herein, a protocol for enantioconvergent transformation of anisole derivatives is disclosed via nickel-catalyzed dynamic kinetic asymmetric cross-coupling of the C(Ar)-OMe bond. Versatile axially chiral heterobiaryls are successfully assembled. Synthetic transformations demonstrate the application potential of this method. Mechanistic studies indicate that the enantioconvergence of this transformation might be accessed through a chiral ligand-controlled epimerization of diastereomeric 5-membered aza-nickelacycle species rather than a conventional dynamic kinetic resolution.

The Effect of Travel-Chain Complexity on Public Transport Travel Intention: A Mixed-Selection Model.

With urban expansion and traffic environment improvement, travel chains continue to grow, and the combination of travel purposes and modes becomes more complex. The promotion of mobility as a service (MaaS) has positive effects on facilitating the public transport traffic environment. However, public transport service optimization requires an accurate understanding of the travel environment, selection preferences, demand prediction, and systematic dispatch. Our study focused on the relationship between the trip-chain complexity environment and travel intention, combining the Theory of Planned Behavior (TPB) with travelers' preferences to construct a bounded rationality theory. First, this study used K-means clustering to transform the characteristics of the travel trip chain into the complexity of the trip chain. Then, based on the partial least squares structural equation model (PLS-SEM) and the generalized ordered Logit model, a mixed-selection model was established. Finally, the travel intention of PLS-SEM was compared with the travel sharing rate of the generalized ordered Logit model to determine the trip-chain complexity effects for different public transport modes. The results showed that (1) the proposed model, which transformed travel-chain characteristics into travel-chain complexity using K-means clustering and adopted a bounded rationality perspective, had the best fit and was the most effective with comparison to the previous prediction approaches. (2) Compared with service quality, trip-chain complexity negatively affected the intention of using public transport in a wider range of indirect paths. Gender, vehicle ownership, and with children/without children had significant moderating effects on certain paths of the SEM. (3) The research results obtained by PLS-SEM indicated that when travelers were more willing to travel by subway, the subway travel sharing rate corresponding to the generalized ordered Logit model was only 21.25-43.49%. Similarly, the sharing rate of travel by bus was only 32-44% as travelers were more willing to travel by bus obtained from PLS-SEM. Therefore, it is necessary to combine the qualitative results of PLS-SEM with the quantitative results of generalized ordered Logit. Moreover, when service quality, preferences, and subjective norms were based on the mean value, with each increase in trip-chain complexity, the subway travel sharing rate was reduced by 3.89-8.30%, while the bus travel sharing rate was reduced by 4.63-6.03%.

Enantioselective alkylative cross-coupling of unactivated aromatic C-O electrophiles.

Nonpolar alkyl moieties, especially methyl group, are frequently used to modify bioactive molecules during lead optimization in medicinal chemistry. Thus transition-metal catalyzed alkylative cross-coupling reactions by using readily available and environmentally benign C-O electrophiles have been established as powerful tools to install alkyl groups, however, the C(sp3)-C(sp2) cross-coupling via asymmetric activation of aromatic C-O bond for the synthesis of alkylated chiral compounds remains elusive. Here, we unlock a C(sp3)-C(sp2) cross-coupling via enantioselective activation of aromatic C-O bond for the efficient synthesis of versatile axially chiral 2-alkyl-2'-hydroxyl-biaryl compounds. By employing a unique chiral N-heterocyclic carbene ligand, this transformation is accomplished via nickel catalysis with good enantiocontrol. Mechanistic studies indicate that bis-ligated nickel complexes might be formed as catalytically active species in the enantioselective alkylative cross-coupling. Moreover, further derivation experiments suggest this developed methodology holds great promise for complex molecule synthesis and asymmetric catalysis.

Neutral Processes Provide an Insight Into the Structure and Function of Gut Microbiota in the Cotton Bollworm.

Gut-associated microbes can influence insect health and fitness. Understanding the structure of bacterial communities provides valuable insights on how different species may be selected and their functional characteristics in their hosts. The neutral model is powerful in predicting the structure of microbial communities, but its application in insects remains rare. Here, we examined the contribution of neutral processes to the gut-associated bacterial communities in Helicoverpa armigera caterpillars collected from different maize varieties at four locations. The gut-associated bacteria can be assigned to 37 Phyla, 119 orders, and 515 genera, with each individual gut containing 17-75% of the OTUs and 19-79% of the genera in the pooled samples of each population. The distribution patterns of most (75.59-83.74%) bacterial taxa were in good agreement with the neutral expectations. Of the remaining OTUs, some were detected in more individual hosts than would be predicted by the neutral model (i.e., above-partition), and others were detected in fewer individual hosts than predicted by the neutral model (i.e., below-partition). The bacterial taxa in the above-partitions were potentially selected by the caterpillar hosts, while the bacteria in the below-partitions may be preferentially eliminated by the hosts. Moreover, the gut-associated microbiota seemed to vary between maize varieties and locations, so ecological parameters outside hosts can affect the bacterial communities. Therefore, the structure of gut microbiota in the H. armigera caterpillar was mainly determined by stochastic processes, and the bacteria in the above-partition warrant further investigation for their potential roles in the caterpillar host.

Multi-Hop Question Generation Using Hierarchical Encoding-Decoding and Context Switch Mechanism.

Neural auto-regressive sequence-to-sequence models have been dominant in text generation tasks, especially the question generation task. However, neural generation models suffer from the global and local semantic semantic drift problems. Hence, we propose the hierarchical encoding-decoding mechanism that aims at encoding rich structure information of the input passages and reducing the variance in the decoding phase. In the encoder, we hierarchically encode the input passages according to its structure at four granularity-levels: [word, chunk, sentence, document]-level. Second, we progressively select the context vector from the document-level representations to the word-level representations at each decoding time step. At each time-step in the decoding phase, we progressively select the context vector from the document-level representations to word-level. We also propose the context switch mechanism that enables the decoder to use the context vector from the last step when generating the current word at each time-step.It provides a means of improving the stability of the text generation process during the decoding phase when generating a set of consecutive words. Additionally, we inject syntactic parsing knowledge to enrich the word representations. Experimental results show that our proposed model substantially improves the performance and outperforms previous baselines according to both automatic and human evaluation. Besides, we implement a deep and comprehensive analysis of generated questions based on their types.

Nickel-Catalyzed Enantioselective Arylative Activation of Aromatic C-O Bond.

The pioneering nickel-catalyzed cross-coupling of C-O electrophiles was unlocked by Wenkert in the 1970s; however, the transition-metal-catalyzed asymmetric activation of aromatic C-O bonds has never been reported. Herein the first enantioselective activation of an aromatic C-O bond is demonstrated via the catalytic arylative ring-opening cross-coupling of diarylfurans. This transformation is facilitated via nickel catalysis in the presence of chiral N-heterocyclic carbene ligands, and chiral 2-aryl-2'-hydroxy-1,1'-binaphthyl (ArOBIN) skeletons are delivered axially in high yields with high ee. Moreover, this versatile skeleton can be transformed into various synthetic useful intermediates, chiral catalysts, and ligands by using the CH- and OH-based modifiable sites. This chemistry features mild conditions and good atom economy.

Coordination Investigation of the Economic, Social and Environmental Benefits of Urban Public Transport Infrastructure in 13 Cities, Jiangsu Province, China.

This study proposed an investigation-based multiple-criteria coordinated model to evaluate the sustainable development of urban public transport (PT) infrastructure, based on economic, social and environmental data from 2009 to 2019. The main problem with the traditional approach for assessing urban PT development is that economic and social benefits are considered individually, but also attention to environmental factors and coordination among the three issues are nearly overlooked. This leads to the likelihood of inaccuracies in the handling/assessment of sustainable development or an imbalance among the attributes in different cities. An investigation-based coordinated model was introduced in which a survey of 35 sub-criteria was conducted to derive the criteria necessary for coupling/coordination. A case study involving 13 cities in Jiangsu Province, China, illustrated the problems in coordinating PT systems and verified the efficacy of the proposed approach. With employing the entropy method, this study validated coordination of the PT infrastructure development of various cities in a balanced manner and used panel regression formulas to analyse the theoretical gap and empirical bottlenecks existing among economic, social and environmental benefits. With the findings of the study, the data-based investigation from 13 cities enabled the city planners/managers (including ones from other cities with similar urban levels) to give the individual priority between the ternary benefits, advance technology, allow big data-based informatisation and implement near-future autonomous PT vehicles.

Wireless Systems and Networks in the IoT.

This Special Issue is focused on breakthrough developments in the field of Wireless Systems and Networks in the IoT. The selected contributions report current scientific progress in a wide range of topics covering clock error compensation in sensor networks, backscatter communication networks, Radio-Frequency Identification (RFID)-based inventory management, resource allocation in Long-Term Evolution (LTE)/LTE-A, (Long Range Wide-Area Network (LoRaWAN) modeling and key generation for the IoT.

Ni-Catalyzed Cross-Coupling of Dimethyl Aryl Amines with Arylboronic Esters under Reductive Conditions.

Herein, we reported a successful Suzuki-Miyaura coupling of dimethyl aryl amines to forge biaryl skeleton via Ni catalysis in the absence of directing groups and preactivation. This transformation proceeded with high efficiency in the presence of magnesium. Preliminary mechanism studies demonstrated dual roles of magnesium: (i) a reductant that reduced Ni(II) species to active Ni(I) catalyst; (ii) a unique promoter that facilitated the Ni(I)/Ni(III) catalytic cycle.

Direct Borylation of Tertiary Anilines via C-N Bond Activation.

The first successful catalytic borylation of unactivated aromatic C-N bonds of tertiary anilines without the preactivation or any directing groups is demonstrated. The reactivity of both N,N-dialkylarylamines and N-arylpyrroles were investigated systematically, and the targeted products were furnished in moderate to good yields. The DFT calculation results indicated that the catalytic cycle is furnished via a five-membered cyclic transition-state due to the steric hindrance of the Ni/NHC catalytic system.

Deoxygenation of Ethers To Form Carbon-Carbon Bonds via Nickel Catalysis.

In this article a successful protocol was developed to construct carbon-carbon bonds by the extrusion of the O atom of ethers via nickel catalysis in the presence of reductants. This methodology is featured as a highly economic route to construct sp3-sp3 C-C bonds through dual C-O activation of ethers with good functional group tolerance.

Practical Cross-Coupling between O-Based Electrophiles and Aryl Bromides via Ni Catalysis.

Cross-coupling of various O-based electrophiles with aryl bromides was developed through Ni-catalyzed C-O activation in the presence of magnesium. Beside carboxylates, carbamates, and ethers, phenols exhibited excellent reactivity under modified conditions. This chemistry was featured as a simple and environmentally benign process with low catalyst loading and easy manipulations. The method exhibited broad substrate scopes.

Performance Analysis of Stop-Skipping Scheduling Plans in Rail Transit under Time-Dependent Demand.

Stop-skipping is a key method for alleviating congestion in rail transit, where schedules are sometimes difficult to implement. Several mechanisms have been proposed and analyzed in the literature, but very few performance comparisons are available. This study formulated train choice behavior estimation into the model considering passengers' perception. If a passenger's train path can be identified, this information would be useful for improving the stop-skipping schedule service. Multi-performance is a key characteristic of our proposed five stop-skipping schedules, but quantified analysis can be used to illustrate the different effects of well-known deterministic and stochastic forms. Problems in the novel category of forms were justified in the context of a single line rather than transit network. We analyzed four deterministic forms based on the well-known A/B stop-skipping operating strategy. A stochastic form was innovatively modeled as a binary integer programming problem. We present a performance analysis of our proposed model to demonstrate that stop-skipping can feasibly be used to improve the service of passengers and enhance the elasticity of train operations under demand variations along with an explicit parametric discussion.

Cu-Catalyzed Alkynylation of Unactivated C(sp(3))-X Bonds with Terminal Alkynes through Directing Strategy.

In this letter, we report an efficient and concise protocol for Cu-catalyzed cross-coupling of unactivated alkyl halides/peusudohalides with terminal alkynes to afford internal alkynes with the assistance of various amides as directing groups. Different alkyl halides/pseudohalides exhibited excellent reactivities, and the inactivated alkyl chlorides and sulfonates showed better reactivity than bromides/iodides. This is the first successful example to apply alkyl chlorides and sulfonates directly in cross-coupling with terminal alkynes in the absence of any additives. A Cu catalyst was found to be more effective than other transition metal catalysts. This reaction also exhibited a broad substrate scope with respect to terminal alkynes.

Exploration of earth-abundant transition metals (Fe, Co, and Ni) as catalysts in unreactive chemical bond activations.

Activation of inert chemical bonds, such as C-H, C-O, C-C, and so on, is a very important area, to which has been drawn much attention by chemists for a long time and which is viewed as one of the most ideal ways to produce valuable chemicals. Under modern chemical bond activation logic, many conventionally viewed "inert" chemical bonds that were intact under traditional conditions can be reconsidered as novel functionalities, which not only avoids the tedious synthetic procedures for prefunctionalizations and the emission of undesirable wastes but also inspires chemists to create novel synthetic strategies in completely different manners. Although activation of "inert" chemical bonds using stoichiometric amounts of transition metals has been reported in the past, much more attractive and challenging catalytic transformations began to blossom decades ago. Compared with the broad application of late and noble transition metals in this field, the earth-abundant first-row transition-metals, such as Fe, Co, and Ni, have become much more attractive, due to their obvious advantages, including high abundance on earth, low price, low or no toxicity, and unique catalytic characteristics. In this Account, we summarize our recent efforts toward Fe, Co, and Ni catalyzed "inert" chemical bond activation. Our research first unveiled the unique catalytic ability of iron catalysts in C-O bond activation of both carboxylates and benzyl alcohols in the presence of Grignard reagents. The benzylic C-H functionalization was also developed via Fe catalysis with different nucleophiles, including both electron-rich arenes and 1-aryl-vinyl acetates. Cobalt catalysts also showed their uniqueness in both aromatic C-H activation and C-O activation in the presence of Grignard reagents. We reported the first cobalt-catalyzed sp(2) C-H activation/arylation and alkylation of benzo[h]quinoline and phenylpyridine, in which a new catalytic pathway via an oxidative addition process was demonstrated to be much preferable. Another interesting discovery was the Co-catalyzed magnesiation of benzylic alcohols in the presence of different Grignard reagents, which proceeded via Co-mediated selective C-O bond activation. In C-O activation, Ni catalysts were found to be most powerful, showing the high efficacy in different kinds of couplings starting form "inert" O-based electrophiles. In addition, Ni catalysts exhibited their power in C-H and C-C activation, which have been proven by us and pioneers in this field. Notably, our developments indicated that the catalytic efficacy in cross coupling between aryl bromides and arenes under mild conditions was not the privilege of several noble metals; most of the transition metals exhibited credible catalytic ability, including Fe, Co, and Ni. We hope our studies inspire more interest in the development of first row transition metal-catalyzed inert chemical bond functionalization.

Direct cross-coupling of benzyl alcohols to construct diarylmethanes via palladium catalysis.

A direct arylation to furnish diarylmethanes from benzyl alcohols was realized through Pd(PPh3)4-catalyzed Suzuki-Miyaura coupling via benzylic C-O activation in the absence of any additives. The arylation is compatible with various functional groups. This development provides an atom- and step-economic way to approach a diarylmethane scaffold under mild and environmentally benign conditions.

Silver-catalysed direct amination of unactivated C-H bonds of functionalized molecules.

Carbon-nitrogen bond formation from inert C-H bonds is an ideal organic transformation and a highly desirable method for the synthesis of N-containing molecules due to its high efficiency and atom economy. In this report, we develop a general reaction to achieve an unprecedented selective intramolecular amination of unactivated C-H bond in the absence of complex directing groups. Functionalized heterocyclic products are built up from readily available linear amines through simple and reliable silver catalysis, representing a new silver-based C-H functionalization. This method displays preference for primary sp(3) C-H bonds and exhibits distinct chemo- and regioselectivity compared to existing methods of direct amination (Hofmann-Löffler-Freytag reaction and nitrene insertion). The study highlights the manipulation of unfunctionalized groups in organic molecules to furnish complex structural units in the natural and bioactive molecules.

[The response characteristics of TM image reflectance to the arid region of soil moisture].

The response characteristics of TM image to the soil moisture in the Tarim River are the research object. Selected the image spectrum (R), spectrum reciprocal (1/R), the logarithm of reciprocal spectrum lg(1/R) and removal normalized difference vegetation index (R(c)) of four spectral index were selected to establish the soil moisture content prediction model, the variance test was used to validate the model significance, the model accuracy level was divided by the posterior variance examination. The results showed that: the model accuracy of the logarithm of reciprocal spectrum lg(1/R) prediction of soil moisture is the highest, and achieved a good level for the monitoring of soil moisture content (0 - 30 cm). The model accuracy of the spectral (R) and spectral reciprocal (1/R) prediction of soil moisture is lower than logarithm of reciprocal spectrum with only the individual layers (0-30, 0-50 cm, etc.) reaching the qualified level or narrouly qualified level. The model accuracy of the removal normalized difference vegetation index (R(c)) prediction of soil moisture is the lowest. Besides, the best prediction depth of every model is the depth of 0-30 cm, and if the soil depth is too deep or too shallow, the prediction accuracy will decrease.