Online soft measurement method for chemical oxygen demand based on CNN-BiLSTM-Attention algorithm.

The measurement of chemical oxygen demand (COD) is very important in the process of sewage treatment. The value of COD reflects the effectiveness and trend of sewage treatment to a certain extent, but obtaining accurate data requires high cost and labor intensity. To1 solve this problem, this paper proposes an online soft measurement method for COD based on Convolutional Neural Network-Bidirectional Long Short-Term Memory Network-Attention Mechanism (CNN-BiLSTM-Attention) algorithm. Firstly, by analyzing the mechanism of the aerobic tank stage in the Anaerobic-Anoxic-Oxic (A2O) wastewater treatment process, the selection range of input variables was preliminarily determined, and the collected sample dataset was subjected to correlation analysis. Finally, pH, dissolved oxygen (DO), electrical conductivity (EC), and water temperature (T) were determined as input variables for soft measurement prediction of COD.Then, based on the feature extraction ability of CNN and the advantage that BiLSTM is able to capture the backward and forward dependencies in time series data, combined with the attention mechanism that can assign higher weights to the key data, a CNN-BiLSTM-Attention algorithm model was established to soft measure COD in the effluent from the aerobic zone of the A2O wastewater treatment process. At the same time, root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and coefficient of determination (R2) were utilized Three indicators were used to evaluate the model, and the results showed that the model can accurately predict the value of COD and has a high accuracy. At the same time, compared with models such as CNN-LSTM-Attention, CNN-BiLSTM, CNN-LSTM, LSTM, RNN, BP, SVM, XGBoost, and RF etc., the results showed that the CNN-BiLSTM Attention model performed the best, proving the superiority of the algorithm model.The Wilcoxon signed-rank test indicates significant differences between the CNN-BiLSTM-Attention model and other models.

Information consumption city and carbon emission efficiency: Evidence from China's quasi-natural experiment.

The transformation of public consumption patterns has become a burning question, but there are few studies on public consumption patterns. Therefore, evaluating the impact of Information consumption city (ICC) policy on carbon emission efficiency holds significant implications. This study settles on 104 pilot cities in China from 2006 to 2020 to assess the impact and the response mechanism of ICC policy on carbon emission efficiency through the time-vary Difference-in-Difference (DID) model. The result shows that: (1) ICC policy significantly promotes the local carbon emission efficiency, which remains robust after a battery of sensitivity tests. (2) It improves carbon emission efficiency through production factors agglomeration effect, industrial structural changing effect, innovation promotion effect, and environmental attention effect; (3) The direct impact of ICC policy on carbon emission efficiency varies across regions with different information consumption and carbon emission base. (4) ICC can improve carbon emission efficiency through the joint implementation of smart city (SC), new urbanization (NU), ecological civilization city construction (EC), Belt and Road Initiative (BR), Broadband China (BC), low-carbon city pilot policy (LCC), and air quality standards (AQS) policy.

Enhanced Feature Extraction Network Based on Acoustic Signal Feature Learning for Bearing Fault Diagnosis.

The method of acoustic radiation signal detection not only enables contactless measurement but also provides comprehensive state information during equipment operation. This paper proposes an enhanced feature extraction network (EFEN) for fault diagnosis of rolling bearings based on acoustic signal feature learning. The EFEN network comprises four main components: the data preprocessing module, the information feature selection module (IFSM), the channel attention mechanism module (CAMM), and the convolutional neural network module (CNNM). Firstly, the one-dimensional acoustic signal is transformed into a two-dimensional grayscale image. Then, IFSM utilizes three different-sized convolution filters to process input image data and fuse and assign weights to feature information that can attenuate noise while highlighting effective fault information. Next, a channel attention mechanism module is introduced to assign weights to each channel. Finally, the convolutional neural network (CNN) fault diagnosis module is employed for accurate classification of rolling bearing faults. Experimental results demonstrate that the EFEN network achieves high accuracy in fault diagnosis and effectively detects rolling bearing faults based on acoustic signals. The proposed method achieves an accuracy of 98.52%, surpassing other methods in terms of performance. In comparative analysis of antinoise experiments, the average accuracy remains remarkably high at 96.62%, accompanied by a significantly reduced average iteration time of only 0.25 s. Furthermore, comparative analysis confirms that the proposed algorithm exhibits excellent accuracy and resistance against noise.

Radical-Induced Dissociation for Oligonucleotide Sequencing by TiO2/ZnAl-Layered Double Oxide-Assisted Laser Desorption/Ionization Mass Spectrometry.

De novo sequencing of oligonucleotides remains challenging, especially for oligonucleotides with post-transcriptional or synthetic modifications. Mass spectrometry (MS) sequencing can reliably detect and locate all of the modification sites in oligonucleotides via m/z variance. However, current MS-based sequencing methods exhibit complex spectra and low ion abundance and usually require coupled instrumentation. Herein, we demonstrate a method of oligonucleotide sequencing using TiO2/ZnAl-layered double oxide (LDO)-assisted laser desorption/ionization (LDI)-MS based on radical-induced dissociation (RID). ·CH2OH radicals can be produced on the surface of a TiO2/ZnAl-LDO matrix via ultraviolet light, inducing an attack on the active site of the oligonucleotide phosphate skeleton to create typical "a-, a-B-, c·-, d-, w-, and y"-type fragments. Compared with the spectra obtained via collision-based methods, such as collision-induced dissociation and higher-energy collisional dissociation, the LDI-MS spectra based on RID exhibit single-charged signals, fewer types of fragments, and a lower proportion of unknown noise peaks. We demonstrate full sequence coverage for a 6-mer 2'-O-methyl-modified oligonucleotide and a 21-mer small interfering RNA and show that RID can sequence oligonucleotides with modifications. Importantly, the mechanism responsible for the RID of the oligonucleotide phosphate skeleton was investigated through offline experiments, demonstrating consistent results with density functional theory calculations.

A PdPt nanoparticle-decorated thiol-functionalized MOF with high peroxidase-like activity for colorimetric sensing of D-glucose and chlorophenol isomers.

The peroxidase (POD)-like catalytic activity of various nanozymes was extensively applied in many significant fields. In this study, a thiol-functionalized MOF-loaded PdPt nanocomposite (UiO-66-(SH)2@PdPt) was fabricated, which possesses superior and selective POD-like activity with strong affinity towards H2O2 and 3,3',5,5'-tetramethylbenzidine under mild conditions. The POD-like property of UiO-66-(SH)2@PdPt was used to sensitively detect the concentration of D-glucose under near-neutral (pH = 6.5) conditions. The detection limit of D-glucose was as low as 2.7 µM, and the linear range of D-glucose was 5-700 µM. In addition, UiO-66-(SH)2@PdPt could accelerate the oxidative coupling chromogenic reaction of chlorophenol (CP) and 4-aminoantipyrine (4-AAP) in the presence of H2O2. Based on this phenomenon, a simple and visualized sensing array for the identification of chlorophenol contaminant isomers was further constructed to finally achieve the effective differentiation of three monochlorophenol isomers and six dichlorophenol isomers. Furthermore, a colorimetric detection method for 2-chlorophenol and 2,4-dichlorophenol was established. This work provides an effective means to improve the catalytic activity and selectivity of nanozymes by introducing an ideal carrier, which will be of significant value for the design of efficient nanozymes.

A nitrogen fixing symbiosis-specific pathway required for legume flowering.

Symbiotic nitrogen fixation boosts legume growth and production in nitrogen-poor soils. It has long been assumed that fixed nitrogen increases reproductive success, but until now, the regulatory mechanism was unknown. Here, we report a symbiotic flowering pathway that couples symbiotic and nutrient signals to the flowering induction pathway in legumes. We show that the symbiotic microRNA-microRNA172c (miR172c) and fixed nitrogen systemically and synergistically convey symbiotic and nutritional cues from roots to leaves to promote soybean (Glycine max) flowering. The combinations of symbiotic miR172c and local miR172c elicited by fixed nitrogen and development in leaves activate florigen-encoding FLOWERING LOCUS T (FT) homologs (GmFT2a/5a) by repressing TARGET OF EAT1-like 4a (GmTOE4a). Thus, FTs trigger reproductive development, which allows legumes to survive and reproduce under low-nitrogen conditions.

How to achieve sustainable development: From the perspective of science and technology financial policy in China.

To solve coordination between economic development and pollutant emissions, it is necessary to face the innovation problem of energy saving and emission reduction. Promoting the effective integration of tech and the financial system is an effective way to solve this problem. According to panel data for prefecture-level cities in China, this paper is based on the pilot policy of combining science and technology with finance implemented in 2011 as a quasi-natural experiment and uses the difference-in-differences (DID) method to evaluate the impact of Science and Technology Financial Policies (STFP) on the air pollutant emission, meanwhile, considering the spatial overflow effect of policy implementation. The research results show that: (1) The STFP has certain inhibitions on pollutant emissions, and this finding holds after a series of robustness tests. (2) The policy has different effects on cities that have different scale, different regions, and different government efficiency. (3) From the results of mechanism analysis, the policy mainly enhances regional pollutant emission reduction capacity through ways such as increasing regional green total factor productivity, enhancing regional science and technology levels, and promoting regional industrial structure optimization. (4) The policy shows a negative spatial spillover effect in reducing pollutant emissions.

Multidimensional identification of disaccharide isomers based on non-covalent complexes and tandem mass spectrometry.

Glycans are the most abundant organic polymers in nature. They are essential to living organisms and regulate a wide range of biological functions. However, mass spectrometry-based identification of glycan isomers remains challenging due to the complexity of their structures including their complex compositions, linkages, and anomeric configurations. In this study, two novel complex ions, the mononuclear copper-bound dimeric ions [(Cu2+)(A)(L-His)-H]+ and the mononuclear copper-bound quaternary ions [(Cu2+)(A)(L-Ser)3-H]+ (where A denotes a disaccharide, and L-Ser/His denotes l-serine/histidine), were designed for the collision-induced dissociation-based identification and relative quantification of 14 disaccharide isomers. When the unique fragmentation patterns of the above two types of complex ions were mapped into a three-dimensional vector, all the isomers were completely distinguished. Of note, the established method is able to identify mixtures of linkage isomers only using tandem mass spectrometry based on linkage-specific fragment ions of histidine-based complex ions. Finally, the method was successfully applied to the identification and relative quantification of two disaccharide isomers (lactose and sucrose) in dairy beverages. In conclusion, the established method is sensitive to subtle structural differences in disaccharide isomers and has the potential to be used for the differentiation of various glycans.

Pd nanoparticles decorated thiol-functionalized MOF as an efficient matrix for differentiation and quantitation of oligosaccharide isomers by laser desorption/ionization mass spectrometry.

Oligosaccharides play a key role in many biological functions, and the accurate identification of oligosaccharide structures is an important prerequisite for a comprehensive understanding of the biological functions of oligosaccharides. MALDI-TOF/TOF tandem mass spectrometry has been considered as a potential technique for the structural characterization of oligosaccharides. In this work, palladium nanoparticles decorated thiol-functionalized metal organic framework nanocomposite (UiO-66-(SH)2@Pd NPs) was fabricated as an efficient matrix to assist laser desorption/ionization mass spectrometry (LDI-MS) for oligosaccharides analysis. The ionization efficiency of oligosaccharides was significantly improved owning to the synergistic effect of MOF and Pd nanoparticles, which is favorable for further oligosaccharide structure identification. By combining LDI-LIFT-TOF/TOF, 24 oligosaccharide isomers including disaccharides, trisaccharides and tetrasaccharides, were effectively distinguished. In addition, the relative quantification curves for isomeric oligosaccharides were established with good linear correlations. The method was successfully applied to the identification and quantification of sucrose and maltose in three batches of Asian ginseng and American ginseng respectively, showing potentiality of MOF materials and metal nanomaterials assisted structural analysis of oligosaccharide isomers.

The miR156b-GmSPL9d module modulates nodulation by targeting multiple core nodulation genes in soybean.

Symbiotic nodulation is initiated in the roots of legumes in response to low nitrogen and rhizobial signal molecules and is dynamically regulated by a complex regulatory network that coordinates rhizobial infection and nodule organogenesis. It has been shown that the miR156-SPL module mediates nodulation in legumes; however, conclusive evidence of how this module exerts its function during nodulation remains elusive. Here, we report that the miR156b-GmSPL9d module regulates symbiotic nodulation by targeting multiple key regulatory genes in the nodulation signalling pathway of soybean. miR156 family members are differentially expressed during nodulation, and miR156b negatively regulates nodulation by mainly targeting soybean SQUAMOSA promoter-binding protein-like 9d (GmSPL9d), a positive regulator of soybean nodulation. GmSPL9d directly binds to the miR172c promoter and activates its expression, suggesting a conserved role of GmSPL9d. Furthermore, GmSPL9d was coexpressed with the soybean nodulation marker genes nodule inception a (GmNINa) and GmENOD40-1 during nodule formation and development. Intriguingly, GmSPL9d can bind to the promoters of GmNINa and GmENOD40-1 and regulate their expression. Our data demonstrate that the miR156b-GmSPL9d module acts as an upstream master regulator of soybean nodulation, which coordinates multiple marker genes involved in soybean nodulation.

One-pot synthesis of an anionic cyclodextrin-stabilized bifunctional gold nanoparticles for visual chiral sensing and catalytic reduction.

A facile one-pot synthetic method for preparing gold nanoparticles by employing sugammadex (SUG), a carboxylic acid functionalized γ-cyclodextrin derivative, as reducing-cum-stabilizing agent herein was reported for the first time. The SUG protected gold nanoparticles (SUG-AuNPs) can work as a colorimetric sensor for visual chiral recognition of α-amino acids enantiomers, especially for lysine (Lys) and asparagine (Asn) enantiomers. The chiral recognition assay was successfully applied to determining the enantiometric excess of L-Lys and L-Asn ranging from -100 % to 100 % respectively. Moreover, the prepared SUG-AuNPs was found to exhibit efficient catalytic activity towards the reduction of toxic 4-nitrophenol by NaBH4 and the efficiency of the system was further demonstrated through the reduction of other typical nitroaromatics under mild condition. The as-synthesized SUG-AuNPs shows good performance for both chiral sensing and reduction activity and thus may facilitate the practical application in the area of both chiral discrimination and catalysis.

Facile enantioseparation and recognition of mandelic acid and its derivatives in self-assembly interaction with chiral ionic liquids.

Mandelic acid and its derivatives are important medical intermediates in the pharmaceutical industry. Different stereoisomers exhibited distinct biological properties to human bodies. Given that, enantioselective recognition and separation of mandelic acid are of great importance. In this study, four novel different types of chiral ionic liquids bearing designed functional groups were synthesized and successful enantioselective precipitation with mandelic acid and its derivatives. That is, (R, R)-chiral ionic liquid 1 can coprecipitated with S-mandelic acid and its derivatives was observed. In addition, good correlation coefficient is achieved by using electrospray mass spectrum at negative ion pattern for quick analysis of the enantioselective precipitation, which could be served as a method of enantioselective recognition. The possible intermolecular interactions are established after systematical studies by NMR spectroscopy and DFT calculations.

Two New Compounds from Schisandra propinqua var. propinqua.

Schisanpropinoic acid (1), a new bergamotane sesquiterpenoid, and schisanpropinin (2), a new tetrahydrofuran lignan with a rare epoxyethane unit, were identified from the stems and leaves of Schisandra propinqua var. propinqua. Their structures were determined based on comprehensive spectroscopic and mass spectrometric analysis. The absolute configuration of 1 was determined by X-ray analysis. Compounds 1 and 2 were tested for their cytotoxic activity against five human tumor cell lines.

Dibenzocyclooctadiene lignans from Kadsura heteroclita.

Sixteen dibenzocyclooctadiene lignans, including eight new ones, kadheterins A-H (1-8), and a new natural product, 9-benzoyloxy-gomisin B (9), were isolated from the stems of K. heteroclita. The structures of 1-9 were elucidated by extensive spectroscopic methods, and their absolute configurations were determined by combining CD with ROESY experiments. Additionally, the absolute configuration of 1 was further confirmed by single crystal X-ray crystallographic analysis. In vitro activity assays showed that 1 exhibited moderate cytotoxicity against HL-60 with IC50 value at 14.59µM.

Triterpenoids from Schisandra propinqua var. propinqua.

Four new triterpenoids, propindilactone T (1), propindilactone U (2), changnanic acid 3-methyl ester (3) and schipropinic. acid (4), together with five known ones (5-9), were isolated and identified from the stems and leaves of Schisandra propinqua var. propinqua; their structures were determined based on spectroscopic and mass spectrometric analyses. The absolute configuration of 1 was confirmed by X-ray analysis. Compounds 1, 2, and 4-9 were tested for their cytotoxic activities against five human tumor cell lines; all were inactive except for 8, which showed weak activity against some of the cell lines.

Two New 18-Norschiartane-type Schinortriterpenoids from Schisandra lancifolia.

Two new 18-norschiartane-type schinortriterpenoids, namely wuwezidilactones Q (1) and R (2) were isolated from the stems of Schisandra lancifolia. Their structures were determined on the basis of extensive spectroscopic analysis. The absolute configurations of the new compounds were further determined by ROESY and an empirical comparison of their experimental ECD spectra with literature.