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As an important ecosystem on the earth, forests not only provide habitat and food for organisms but also play an important role in regulating environmental elements such as water, atmosphere, and soil. The quality of forest waters directly affects the health and stability of aquatic ecosystems. Chemical oxygen demand (COD) is commonly used to assess the concentration of organic matter and the pollution status of water bodies, which is helpful in assessing the impact of human activities on forest ecosystems. To effectively measure the COD value, water samples were prepared from Purple Mountain in Nanjing and nearby rivers and lakes. Using ultraviolet–visible (UV–vis) and fluorescence (FLU) spectroscopy combined with data fusion, the COD values of the forest water were accurately measured. Due to the large dimensionality of spectral data, the successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) were applied to the selection of characteristic wavelengths. By establishing a discriminant model for single-level data and using the voting mechanism to fuse the output results of different models, a relatively high determination coefficient (R2) of 0.9932 and a low root-mean-square error (RMSE) of 0.4582 were obtained based on the decision-level data fusion model. Compared with the single-spectrum and feature-level fusion models, the decision-level fusion scheme achieves an efficient, comprehensive, and accurate quantification of the water COD value. This study has important applications in forest protection, water resources management, sewage treatment, and the food processing field.

Here, we prepared a series of novel osthole-type ester derivatives modified in the lactone ring of osthole, which is isolated from Cnidium monnieri. The positions of H-3 and H-4 of the representative compound 4z were determined by a 1H-1H COSY spectrum. By opening the lactone ring of osthole, the double bonds at the C-3 and C-4 positions of diol 3 and esters 4a-4z, 4a', and 4b' were still retained as a Z configuration. That is, H-3 and H-4 of compounds 3 and 4a-4z, 4a', and 4b' were all in the cis relationship. The steric configurations of 4k, 4v, and 4z were further undoubtedly determined by single-crystal X-ray diffraction. Against Tetranychus cinnabarinus Boisduval, four aliphatic esters 4c (R = n-C3H7; LC50: 0.31 mg/mL), 4d (R = CH3(CH2)10; LC50: 0.24 mg/mL), 4a' (R = CH3(CH2)9; LC50: 0.28 mg/mL), and 4b' (R = CH3(CH2)12; LC50: 0.32 mg/mL) showed the most promising acaricidal activity, and compounds 4c, 4d, and 4a' also exhibited a potent control efficiency. Especially, compound 4d exhibited greater than fivefold acaricidal activity of the precursor osthole (LC50: 1.22 mg/mL). Against Mythimna separata Walker, compounds 4g, 4l, and 4m displayed 1.6-1.8-fold potent insecticidal activity of osthole. It demonstrated that the lactone ring of osthole is not necessary for the agricultural activities, thiocarbonylation of osthole was not beneficial for the agricultural activities, introduction of R as an aliphatic chain is vital for the acaricidal activity, notably, the length of the aliphatic chain is related to the acaricidal activity, 4d could be further studied as a lead acaricidal agent, and to the aromatic series, R containing the fluorine atom(s) is important for the insecticidal activity.

Accurate engine performance models are important for model-based performance evaluation of aero engine. The accuracy of the model often depends on engine component maps, so there is a need for a method that can accurately correct the component maps of the model over a wide range. In this paper, a new method for modifying component maps is proposed, this method combines the correction of the scaling factors with the solution process of the off-design working point, and uses the adjustment of the variable geometric parameters of the engine to change the position of the working line, in order to obtain more correction results and guarantee high accuracy in a wider range. The method is validated by taking the main fan of the Adaptive Cycle Engine (ACE), an ideal power unit for a new generation of multi-purpose and ultra-wide working range aircraft, as an example. The results show that the maximum error between the corrected component maps and the target maps is less than 1%. New possibility for more precise component maps can be realized in this paper.

Background Spirodiclofen is a spirocyclic tetronic acid-type acaricidal agent. Nowadays, serious pests resistance to spirodiclofen and cross-resistance to other acaricides has appeared. To overcome pests resistance and discover new potential agrochemicals, a series of ether derivatives were prepared based on spirodiclofen as a lead compound. Their pesticidal activities were investigated against three typically agricultural pests, Mythimna separata Walker, Aphis citricola Van der Goot and Tetranychus cinnabarinus Boisduval. Results Four steric structures of products 5e, 5 f, 5i and 5j were determined by single-crystal X-ray diffraction. Against Tetranychus cinnabarinus, compounds 5b, 5 f and 5 L exhibited potent acaricidal activity, and their good control effects in the glasshouse were observed when compared with spirodiclofen, especially the control efficiency of compound 5b was comparable to that of spirodiclofen; against Mythimna separata, compound 5j showed >1.8-fold potent insecticidal activity of spirodiclofen; against Aphis citricola, compounds 5d and 5j displayed >2.0-fold potent aphicidal activity of spirodiclofen. The relationships between their structures and agricultural activities were also discussed. Conclusion Compounds 5b and 5d could be further studied as acaricidal and aphicidal agents, respectively; compound 5j can be considered as a lead compound for the insecticidal and aphicidal activities. This will pave the way for future application of these derivatives as pesticide substitutes for spirodiclofen. This article is protected by copyright. All rights reserved.

Abstract: Natural products are an invaluable source for the discovery of drug and pesticide candidates. Piperine, a simple and pungent alkaloid, is isolated from several plants of Piperaceae. Piperine and its derivatives displayed a wide range of biological properties, such as antitumor activity, anti-inflammatory activity, antioxidant activity, neuroprotective activity, insecticidal activity, etc. In recent years, lots of works focused on the biological activities, mechanisms of action, total synthesis, and structural modifications of piperine and its derivatives have been conducted. To the best of our knowledge, however, few review articles related to the biological activities, mechanisms of action, total synthesis, and structural modifications of piperine and its derivatives have been reported to date. Therefore, this review summarizes the research advances (from 2014 to 2020) of piperine and its derivatives regarding bioactivity, mechanisms of action, total synthesis, and structural modifications. Meanwhile, the structure-activity relationships of piperine and its derivatives are also discussed.

Ozonation is a significant technology for the mitigation of pollutants in water. The second-order reaction rate constant (k

In continuation of our program to develop natural-product-based pesticidal candidates, matrinic/oxymatrinic amides were obtained through structural optimization of matrine. N'-(4-Fluoro)phenyl-N-(4-bromo)phenylsulfonyloxymatrinic amide (IIm) showed potent insecticidal activity against Mythimna separata. N-(Un)substituted phenylsulfonylmatrinic acids (3a-c) exhibited promising acaricidal activity against Tetranychus cinnabarinus. By qRT-PCR analysis of nAChR subunits and AChE genes and determination of AChE activity of (un)treated T. cinnabarinus, it suggested that the open lactam ring of matrine and carboxyl group and (4-methyl)phenylsulfonyl of N-(4-methyl)phenylsulfonylmatrinic acid (3b) were necessary for action with α2, α4, α5, and β3 nAChR subunits; compound 3b was an inhibitor of AChE in T. cinnabarinus, and AChE was one possible target of action in T. cinnabarinus against 3b; and compound 3b may be an antagonist of nAChR and AChE in T. cinnabarinus.

Matrine, a quinolizidine alkaloid isolated from the roots of Sophora flavescens, is a naturally non-food bioactive product. To discover new non-food bioactive product-based pesticides, a series of 15-chloro-18-oximinoether derivatives of matrine were prepared by structural modifications of matrine. Compounds 7 m, 7o, 7q, 7 s, and 7 t display potent insecticidal activity against Mythimna separata Walker. Compounds 7b (R2 = n-butyl) and 7 l (R2 = p-methylbenzyl) exhibit greater than 6 folds more pronounced acaricidal activity than matrine against Tetranychus cinnabarinus Boisduval. Through reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time polymerase chain reaction (qRT-PCR) analysis, it is found that introduction of the chlorine atom and the oximinoether moiety at the C-15 and C-18 positions of matrine is important for acting with nAChR α1, α2 and α4 subunits in T. cinnabarinus; α1, α2, α4 and β3 subunits may be the target of action of compound 7b against T. cinnabarinus; structural modification on the lactam ring of compound 1 can lead to the change of mode of action on VGSC in T. cinnabarinus.

With the rapid development of the Internet, the wide circulation of disinformation has considerably disrupted the search and recognition of information. Despite intensive research devoted to fake text detection, studies on fake short videos that inundate the Internet are rare. Fake videos, because of their quick transmission and broad reach, can increase misunderstanding, impact decision-making, and lead to irrevocable losses. Therefore, it is important to detect fake videos that mislead users on the Internet. Since it is difficult to detect fake videos directly, we probed the detection of fake video uploaders in this study with a vision to provide a basis for the detection of fake videos. Specifically, a dataset consisting of 450 uploaders of videos on diabetes and traditional Chinese medicine was constructed, five features of the fake video uploaders were proposed, and a Naive Bayesian model was built. Through experiments, the optimal feature combination was identified, and the proposed model reached a maximum accuracy of 70.7%.

Celecoxib is commonly used for pain management after total hip arthroplasty (THA), while the optimal timing of analgesic celecoxib remains unclear. This randomized, controlled study aimed to investigate the pain control efficacy and safety of preoperative celecoxib versus postoperative celecoxib in osteoarthritis (OA) patients undergoing THA. Totally, 192 hip OA patients about to undergo THA were randomized into pre-treatment group (N = 96) and post-treatment group (N = 96). The former was given 400 mg celecoxib at 4 h before THA, 200 mg at 4 h after THA, and then 200 mg every 12 h until 72 h post-operation. The latter was given 400 mg celecoxib at 4 h after THA, and then 200 mg every 12 h until 72 h post-operation. Pain at rest visual analog scale (VAS) score at 6 h, and pain at flexion VAS scores at 6 h, 12 h, and on D1, D2 were decreased in pre-treatment group compared to post-treatment group (all P 0.05). Furthermore, additional consumption of patient-controlled analgesia (PCA) (P = 0.006) and total consumption of PCA (P = 0.006) were both reduced in pre-treatment group compared to post-treatment group. Meanwhile, compared to post-treatment group, patient satisfaction in pre-treatment group was higher on D1 (P = 0.010) and D2 (P = 0.039). While, Harris hip score showed no difference between pre-treatment group and post-treatment group on M1 or M3 (both P 0.05). In conclusion, preoperative celecoxib exhibits better analgesic efficacy and patients' satisfaction management with similar tolerance compared to postoperative celecoxib in hip OA patients undergoing THA.

Spirodiclofen is a spirocyclic tetronic acid-type acaricidal agent. Nowadays, serious pests resistance to spirodiclofen and cross-resistance to other acaricides has appeared. To overcome pests resistance and discover new potential agrochemicals, a series of ether derivatives were prepared based on spirodiclofen as a lead compound. Their pesticidal activities were investigated against three typically agricultural pests, Mythimna separata Walker, Aphis citricola Van der Goot and Tetranychus cinnabarinus Boisduval.Four steric structures of compounds 5e, 5f, 5i and 5j were determined by single-crystal X-ray diffraction. Against T. cinnabarinus, compounds 5b, 5f and 5l exhibited potent acaricidal activity, and their good control effects in the glasshouse were observed when compared with spirodiclofen, especially the control efficiency of compound 5b was comparable to that of spirodiclofen; against M. separata, compound 5j showed 1.8-fold potent insecticidal activity of spirodiclofen; against A. citricola, compounds 5d and 5j displayed 2.0-fold potent aphicidal activity of spirodiclofen. The relationships between their structures and agricultural activities were also discussed.Compounds 5b and 5d could be further studied as acaricidal and aphicidal agents, respectively; compound 5j can be considered as a lead compound for the insecticidal and aphicidal activities. This will pave the way for future application of these derivatives as pesticide substitutes for spirodiclofen. © 2021 Society of Chemical Industry.

Derivatives of monosaccharides and oligosaccharides play important roles in biological processes. Monosaccharides are the single carbohydrate building blocks, such as glucose, xylose, and fructose. Oligosaccharides are composed of 2-10 monosaccharides, including disaccharides and trisaccharides. Moreover, monosaccharides, oligosaccharides and their derivatives are vital molecules with various biological properties, including anticancer activity, antiviral activity, insecticidal activity, antimicrobial activity, and antioxidant activity. This review covers a survey of structural modifications, biological activities, and mechanisms of action of monosaccharides, oligosaccharides and their derivatives. Additionally, their structure-activity relationships are also concluded.

BACKGROUND In order to discover natural-product-based pesticidal candidates, a series of coumarin-like derivatives containing oxime ester fragments at the C-8 position were prepared by structural modification of osthole, a natural plant product isolated from Cnidium monnieri. Their pesticidal activities were evaluated against two typically fruit trees/crop-threatening agricultural pests, Mythimna separata Walker and Tetranychus cinnabarinus Boisduval. RESULTS Osthole was regioselectively oxidized by selenium dioxide to give the E-isomer, (2'E)-3'-formaldehydylosthole (2). Four key steric structures of 2, (2'E, 4'E)-(o-chloropyrid-3-ylcarbonyl)oximinylosthole (4o), (2'E, 4'E)-(styrylcarbonyl)oximinylosthole (4t), and (2'E, 4'E)-(acetyl)oximinylosthole (4w) were undoubtedly confirmed by X-ray crystallography. Against T. cinnabarinus, it is noteworthy that (2'E, 4'E)-(p-chlorophenylcarbonyl)oximinylosthole (4c) exhibited over three-fold more potent acaricidal activity of the precursor osthole, with especially good control efficiency observed in the glasshouse. Against M. separata, compounds 4c and (2'E, 4'E)-(p-nitrophenylcarbonyl)oximinylosthole (4f) showed the most pronounced growth inhibitory activity. The relationships between their structures and agricultural activities also were studied. CONCLUSION These results demonstrate that compound 4c could be further structurally modified as pesticidal agents. It will lay the foundation for future application of osthole derivatives as pesticides. © 2020 Society of Chemical Industry.

A total of 20 esters of fraxinellone C4/10-oxime were synthesized and determined by melting points, optical rotation, infrared spectra, proton nuclear magnetic resonance spectra, and high-resolution mass spectrometry spectra. Two steric configurations of compounds 7i and 8i were unambiguously confirmed by X-ray crystallography. Additionally, their pesticidal activities were assessed on two typical lepidopteran pests, Mythimna separata Walker and Plutella xylostella Linnaeus. Generally, all compounds exhibited less potent oral toxicity than toosendanin against third-instar larvae of P. xylostella. However, all compounds showed the growth inhibitory property against early third-instar larvae of M. separata. Notably, compounds 7m, 8b, 8k, 9, and 11 displayed more potent pesticidal activity than toosendanin. This demonstrated that introducing the C-4 carbonyl or oxime group on fraxinellone resulted in more promising derivatives than those bearing a C-10 carbonyl or oxime substituent.

To explore candidate pesticides from non-food bioactive products, twenty-five new matrine-type alkaloid analogs, 15-chloro-18-(acyl)oximinylmatrines (6a–6y), were semi-synthesized from matrine isolated from the roots of Sophora flavescens Aiton (Fabaceae). The spatial configurations of six derivatives were determined by X-ray crystallography. Analogs 6f (R = (CH2)9CH3) and 6g (R = (CH2)10CH3) all showing the pronounced insecticidal and acaricidal activities against two threatening pests Mythimna separata Walker and Tetranychus cinnabarinus Boisduval, could be used as the lead compounds for further structural optimization. It suggested that R as the aliphatic alkane with long straight chain was necessary for the insecticidal and acaricidal activities of matrine oximino esters.

To obtain novel potentially botanical insecticides from non-food bioactive products for an Integrated Pest Management system, a series of monosaccharides-matrine conjugates were prepared by modifications of the natural alkaloid matrine from Sophora flavescens under ultrasonic irradiation (yields were increased from 18 to 62% (without ultrasound) to 48–67 %, whereas the amount of reactants was reduced, especially the reaction time was sharply decreased from 3−16 h (without ultrasound) to 1 h). Against Mythimna separata, 3f and If (2.6 folds of that of matrine) exhibited the most promising insecticidal activity; against Tetranychus cinnabarinus, 3d and 3e (about 7.0 folds of that of matrine) showed the most pronounced acaricidal activity. Especially 3d and 3e displayed good control effects in the greenhouse.

Besides structural modification of natural bioactive products to afford promising agrochemical candidates, investigation of their mechanisms of action against pests is also an important strategy to obtain novel potentially botanical pesticides. N-(p-Ethyl)phenylsulfonylmatrinic acid (2), derived from an natural alkaloid matrine (1), exhibited about 5.9-fold more pronounced acaricidal activity than 1 against the adult females of Tetranychus cinnabarinus Boisduval, and good control efficiency in the greenhouse. By comparison of nAChR, AChE and VGSC of treated and untreated T. cinnabarinus via RT-PCR and qRT-PCR analysis, it was found that compound 2 could activate nAChR and VGSC via up-regulation of nAChR α1, α4 and α5 subunits and VGSC expressions; compound 2 may be the AChE and AChE enzyme inhibitor. Importantly, a scheme of compound 2 interaction with nAChR, AChE and VGSC of T. cinnabarinus was proposed. It will lay the foundation for future optimization and application of matrine derivatives as agrochemicals.

Nonlinear optical (NLO) materials have been widely investigated in view of the applications in optoelectronic devices, and so forth. Recently, it is revealed that the species involving the excess electron can exhibit the considerable NLO response, where the excess electron plays an important role in increasing the first hyperpolarizability. It is worth mentioning that the intriguing electride/alkalide compounds with excess electron have been realized in experiment. In this work, we have presented a summary of our insights on how to introduce the excess electron in the related systems to effectively improve their NLO properties by considering different crucial factors involving the complexant, doped metal atom and interaction mode between them, and so forth. It is of benefit for promoting the design of new high-performance NLO materials involving excess electron in the near future. © 2015 Wiley Periodicals, Inc.

Using DFT methods, the electronic properties and the first hyperpolarizabilities of boron-heterofullerene-(super)alkali dyads: M3O-BC59 (M = Li, Na and K) and K@n-BC59 (n = 5 and 6) were systematically investigated. It is found that both M3O and K can effectively bind to BC59 with high binding energies (2.50-2.69 eV for K and 4.24-5.14 eV for M3O). The interaction between K and BC59 in K@n-BC59 is identified as primarily ionic in nature, whereas that between the superalkali M3O unit and BC59 becomes much stronger owing to the formation of a strong chemical bond (B-O bond). Moreover, compared with the sole parent cluster BC59 (619 au), both K@n-BC59 (n = 5 and 6) and M3O-BC59 (M = Li, Na and K), possess large first hyperpolarizabilities (β0), which are 3352, 2621 and 4921, 5440 and 7800 au, respectively, where the superalkali doped dyads (M3O-BC59) are much superior to the simple alkali exo-hedral species (K@n-BC59), and heavier superalkali can be more powerful in enhancing the β0 values of M3O-BC59. Clearly, these superalkali doped dyads M3O-BC59, formal donor-acceptor (DA) chromophores, exhibit not only excellent stability but also large first hyperpolarizability; therefore, they are expected to be potential candidates for excellent second-order NLO materials.

The structures, energetics and stability of the [P, X, Y] (X = C, Si; Y = O, S) radicals are explored by means of the density functional theory and ab initio levels. Seventeen [P, X, Y] isomers and 14 interconversion transition states are obtained at the B3LYP/6-311G(d) level. At the CCSD(T)/6-311 + G(2df)//QCISD/6-311G(d) + ZPVE level, the lowest-lying isomers are the linear PCO 1a (0.0 kcal/mol), PCS 1b (0.0) and the three-membered ring cPSiO 1c (0.0), cPSiS 1d (0.0) on their respective potential energy surfaces. These four isomers exhibit considerably not only thermodynamic but also kinetic stabilities. Additionally, the cyclic cPCS 2b (32.8) and linear PSiS 2d (18.6) possess also high kinetic stability. All of six isomers 1a, 1b, 2b, 1c, 1d and 2d are considerably stabilized by a barrier of at least 20 kcal/mol, and may be detected in the laboratory or interstellar space. Their valence bond structures and possible formation strategies in the laboratory and space are discussed in detail. Finally, the s...

With characteristics of small volume, low cost and high reliability, MEMS inertial sensors are developing into one of the mainstream sensors in inertial navigation system, and its output precision has a great effect on the overall system precision. In this paper, the random error of inertial sensors output are mainly discussed and identified by Allan variance. To analysis the random error in the output of MEMS sensors, which contribute to improve the system precision, Mathematical simulations and actual tests are carried out.

Sentinel surveillance of Keshan disease (KD) is limited by unable to give the prevalence rates and their estimates. This study was to find the national KD prevalence and the estimated patient numbers to provide evidence toward modifying the policy of KD prevention and control.Using a probability proportional to population size, randomized, multistage, and cluster sampling, we surveyed 101,127, measured grain selenium levels; and surveyed household income with pre-designed questionnaires.The national prevalence rates of KD, chronic KD and latent KD were 2.21%, 0.50%, and 1.71% respectively. Chronic KD patients are mainly in the provinces where KD had been seriously epidemic. The KD prevalence rate was higher in females (2.20%) than in males (1.98%). These were also higher in older age groups. The cases younger than 30 years accounted for 13.6%, indicating the possibility that KD is still occurring. Nationally, the estimated numbers of KD and chronic KD patients are 1,675,500 (95% CI, 1,608,500-1,747,300) and 379,800 (95% CI, 346,700-412,800) respectively. Multiple logistic regression analysis indicated that family income was a significant dependent variable (OR: -0.258, 95% CI: -0.332 to -0.185, p0.001). More than 2000 chronic KD patients found in the study were treated in 2009-2011. The limitation of this study was that sampling size was determined at national level.KD is still a public health issue among the people of the historically severe endemic areas. Selenium supplementation, self-management program for chronic KD patients and translation epidemiology of KD surveillance should be strengthened.

This study explores whether the declining prevalence of Keshan disease is associated with increasing selenium levels in Keshan disease areas in Heilongjiang province. Six counties endemic with Keshan disease and three non-endemic counties were selected as study areas. In each county, two townships and in each township one village were chosen in which to survey ten families about head hair, grain, and soil samples and to obtain demographic information. Selenium was measured with hydride generation-atomic fluorescence spectrometry. In each county endemic with Keshan disease, one of the villages was chosen to investigate the prevalence of the disease. We collected 534 head hair samples, 446 staple food samples, and 180 soil samples. The selenium levels of head hair and corn in the endemic counties were significantly lower than those in non-endemic counties. Family demographic information was homologous except for the composition of staple food. More residents in Keshan disease areas preferred flour and corn. The detection rate for latent Keshan disease had a significantly negative correlation with the corn selenium level in six counties endemic with Keshan disease. As the population in this region is still at risk for Keshan disease, selenium surveillance measures should be intensified.