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Abstract: Cross coupling protocols were applied for the synthesis of 3-(4-heteroaryl-phenyl)-8-oxabicyclo[3.2.1]oct-2-ene-2-carboxylic acid methyl esters. Stille conditions produced the corresponding products in reasonable yields. Samarium iodide reduction of the resulting coupling products produced the 2β-carbomethoxy-3α-aryl-8-oxabicyclo[3.2.1]octane diastereoisomers as the major, and the 2β-carbomethoxy-3β-aryl-8-oxabicyclo[3.2.1]octane diastereoisomer as the minor products. Both diastereomers manifested inhibition of the dopamine (DAT) and serotonin (SERT) transporters, with some selectivity for SERT inhibition. [Copyright &y& Elsevier]

Cocaine is a powerful reinforcer and stimulant that binds to specific recognition sites associated with monoamine transporters in the mammalian brain. The search for a functional antagonist to the addictive properties of cocaine has focused on the discovery of a molecule that can inhibit cocaine binding to the dopamine transporter (DAT) but continue to allow dopamine transport by the DAT. No such dopamine-sparing cocaine antagonist has been reported and it is becoming evident that dopamine-sparing antagonism of the pharmacological effects of cocaine by a classical antagonist may not be possible. Herein we present a new concept for the design of dopamine-sparing cocaine antagonists. A unique approach is utilized to deliver an inhibitor that binds irreversibly to the DAT, then cleaves and leaves behind a small fragment attached to the DAT that blocks access by cocaine but permits dopamine transport. The design of these compounds takes advantage of a cysteinyl sulfhydryl group in the DAT. This group is hypothesized to attack the incoming inhibitor and lead to selective inhibition of the cocaine binding site while sparing dopamine transport. This concept of a mechanism based irreversible dopamine-sparing cocaine antagonist has now been demonstrated to be viable and, as example, the unsaturated 6 showed inhibition of cocaine (63%) at the DAT after 24 h incubation, while at that point considerably less inhibition of dopamine is manifested (23%). In contrast, the epoxide 7 showed a greater inhibition of dopamine reuptake than cocaine binding at 24 h (68% versus 18%). [Copyright &y& Elsevier]

Due to the superiority of convolutional neural networks, many deep learning methods have been used in image classification. The enormous difference between natural images and remote sensing images makes it difficult to directly utilize or modify existing CNN models for remote sensing scene classification tasks. In this article, a new paradigm is proposed that can automatically design a suitable CNN architecture for scene classification. A more efficient search framework, RS-DARTS, is adopted to find the optimal network architecture. This framework has two phases. In the search phase, some new strategies are presented, making the calculation process smoother, and better distinguishing the optimal and other operations. In addition, we added noise to suppress skip connections in order to close the gap between trained and validation processing and ensure classification accuracy. Moreover, a small part of the neural network is sampled to reduce the redundancy in exploring the network space and speed up the search processing. In the evaluation phase, the optimal cell architecture is stacked to construct the final network. Extensive experiments demonstrated the validity of the search strategy and the impressive classification performance of RS-DARTS on four public benchmark datasets. The proposed method showed more effectiveness than the manually designed CNN model and other methods of neural architecture search. Especially, in terms of search cost, RS-DARTS consumed less time than other NAS methods. [ABSTRACT FROM AUTHOR]

• The Krafft temperature was reduced by introducing double bond in the hydrophobic chain of surfactant. • The tertiary amine is protonated with a pH adjuster to obtain a low Krafft temperature of tertiary amine salt. • A thickener with low temperature stability at −5 °C was obtained. • A quantitative structure–activity relationship between the surfactant and its Krafft temperature was established. Solve the problem of freezing and blocking of clean fracturing fluid thickener during winter fracturing operations in the north, which is conducive to improving the efficiency of fracturing operations and oil and gas production rate. In this paper, four kinds of fatty acid amidopropyl dimethyl tertiary amine were successfully prepared and characterized with FT-IR and 1H NMR. Their acid values and Krafft temperature are discussed. The molecular structures of the four kinds of fatty acid amidopropyl dimethyl tertiary amine salts were optimized using Gaussian09 software, then their single point energies were calculated. A quantitative structure–property relationship (QSPR) model was established to predict Krafft temperature of the four kinds of fatty acid amidopropyl dimethyl tertiary amine salts. N -(3-(Dimethylamino)propyl)oleamide (PKO-O), (9 Z ,12 Z)- N -(3-(dimethylamino)propyl)octadeca-9,12-dienamide (PKO-LO) were selected as the main agent. The optimal thickener formulation O1-8 and O2-1 were optimized by single factor experiment and orthogonal test respectively. O2-1 thickener has high low-temperature stability at −5 °C. The viscosity increase property, gel breaking property, rheological property, and viscoelasticity of the clean fracturing fluid obtained by cross-linking O1-8 with O2-1 thickener were evaluated and the properties of O1-8 thickener are better. The result shows that the O1-8 thickener basically meets the conditions of the winter fracturing construction site, and has more practical application significance. [ABSTRACT FROM AUTHOR]

Macaque monkey is a rare substitute which plays an important role for human beings in relation to psychological and spiritual science research. It is essential for these studies to accurately estimate the pose information of macaque monkeys. Many large-scale models have achieved state-of-the-art results in pose macaque estimation. However, it is difficult to deploy when computing resources are limited. Combining the structure of high-resolution network and the design principle of light-weight network, we propose the attention-refined light-weight high-resolution network for macaque monkey pose estimation (HR-MPE). The multi-branch parallel structure is adopted to maintain high-resolution representation throughout the process. Moreover, a novel basic block is designed by a powerful transformer structure and polarized self-attention, where there is a simple structure and fewer parameters. Two attention refined blocks are added at the end of the parallel structure, which are composed of light-weight asymmetric convolutions and a triplet attention with almost no parameter, obtaining richer representation information. An unbiased data processing method is also utilized to obtain an accurate flipping result. The experiment is conducted on a macaque dataset containing more than 13,000 pictures. Our network has reached a 77.0 AP score, surpassing HRFormer with fewer parameters by 1.8 AP. [ABSTRACT FROM AUTHOR]

Within the current process of large-scale dairy-cattle breeding, to address the problems of low recognition-accuracy and significant recognition-error associated with existing visual methods, we propose a method for recognizing the feeding behavior of dairy cows, one based on an improved RefineMask instance-segmentation model, and using high-quality detection and segmentation results to realize the recognition of the feeding behavior of dairy cows. Firstly, the input features are better extracted by incorporating the convolutional block attention module into the residual module of the feature extraction network. Secondly, an efficient channel attention module is incorporated into the neck design to achieve efficient integration of feature extraction while avoiding the surge of parameter volume computation. Subsequently, the GIoU loss function is used to increase the area of the prediction frame to optimize the convergence speed of the loss function, thus improving the regression accuracy. Finally, the logic of using mask information to recognize foraging behavior was designed, and the accurate recognition of foraging behavior was achieved according to the segmentation results of the model. We constructed, trained, and tested a cow dataset consisting of 1000 images from 50 different individual cows at peak feeding times. The method's effectiveness, robustness, and accuracy were verified by comparing it with example segmentation algorithms such as MSRCNN, Point_Rend, Cascade_Mask, and ConvNet_V2. The experimental results show that the accuracy of the improved RefineMask algorithm in recognizing the bounding box and accurately determining the segmentation mask is 98.3%, which is higher than that of the benchmark model by 0.7 percentage points; for this, the model parameter count size was 49.96 M, which meets the practical needs of local deployment. In addition, the technologies under study performed well in a variety of scenarios and adapted to various light environments; this research can provide technical support for the analysis of the relationship between cow feeding behavior and feed intake during peak feeding periods. [ABSTRACT FROM AUTHOR]

The application of ionic liquids is prevalent in various industries, including pharmaceutical, chemical, and aerospace, especially in environments with high temperatures. Thus, the importance of researching the characteristics and mechanism of the pyrolysis hazard of ionic liquids cannot be overemphasized. This research presents a systematic study of a new versatile ionic liquid, 1-propyl-3-methylimidazolium nitrate ([Pmim][NO 3 ]). The flash-ignition temperature, thermal decomposition and thermal runaway characteristics of [Pmim][NO 3 ] were analyzed using various techniques, including thermogravimetric analyzer, differential scanning calorimetry, flash-ignition temperature tester, and accelerating rate calorimeter, for determining its major hazard characteristics. The main thermodynamic and safety parameters, as well as the reaction pattern of the pyrolysis process, were obtained. Additionally, an assessment was conducted to determine the potential occurrence and seriousness of a runaway reaction of [Pmim][NO 3 ] decompose. The present study is of significant importance in improving the intrinsic safety level of ionic liquids in the processes of synthesis, utilization, storage, and transportation. [ABSTRACT FROM AUTHOR]

Abstract: Cocaine is a potent stimulant of the central nervous system. Its reinforcing and stimulant properties have been associated with inhibition of the dopamine transporter (DAT) on presynaptic neurons. In the search for medications for cocaine abuse, we have prepared 2-carbomethoxy-3-aryl-8-thiabicyclo[3.2.1]octane analogues of cocaine. We report that this class of compounds provides potent and selective inhibitors of the DAT and SERT. The selectivity resulted from reduced activity at the SERT. The 3β-(3,4-dichlorophenyl) analogue inhibits the DAT and SERT with a potency of IC50 =5.7nM and 8.0nM, respectively. The 3-(3,4-dichlorophenyl)-2,3-unsaturated analogue inhibits the DAT potently (IC50 =4.5nM) and selectively (>800-fold vs SERT). Biological enantioselectivity of DAT inhibition was limited for both the 3-aryl-2,3-unsaturated and the 3α-aryl analogues (2-fold), but more robust (>10-fold) for the 3β-aryl analogues. The (1R)-configuration provided the eutomers. [Copyright &y& Elsevier]

Explosive vessels are vulnerable to shock wave impacts during operation processing. It is necessary to explore the vessel’s vibration characteristics. In this paper, acceleration sensors were adopted to collect vibration acceleration signals at the inner and outer surfaces of the composite double-layer explosive vessel under explosive loading. Then, the effective vibration velocity curve can be obtained by fitting polynomials to eliminate the acceleration integral trend. Thereafter, Hilbert-Huang Transform (HHT) was applied to analyze the time-frequency distribution of vibration velocity signals. The results showed that the special “steel plate–buffer interlayer–steel plate” structure can effectively attenuate the explosion vibration effect, and the frequency distribution range of vibration signal at the inner surface was wider than that at the outer surface, and furthermore the main vibration frequency was close to the natural frequency at the inner surface. Meanwhile, vibration amplitude and the main vibration frequency decreased obviously compared with the outer surface, and the vibration time of 0–200 Hz low-order frequency was shortened. The above researches closely linked the energy distribution with frequency of vibration signals and provided valuable reference for safer protection and vibration reduction design of explosive vessel. [ABSTRACT FROM AUTHOR]