Search

The decision-making of generator start-up sequence plays a pivotal role in the power system restoration process following the blackout. In this paper, an optimized deep Q-learning network (DQN) algorithm is proposed to address this challenge. The generator start-up process is modeled as a Markov Decision Process (MDP) based on its characteristics. The DQN is tasked with deciding both the generator start-up sequence and the corresponding restoration path. To address the limitations of DQN, such as low exploration efficiency and slow convergence, the study incorporates the Artificial Potential Field (APF) algorithm to refine the reward function of it. This integration results in the development of the F-DQN (APF-DQN) algorithm, which enhances training efficiency. The effectiveness of this proposed method is demonstrated through the IEEE 39-bus test system. The results reveal that the DQN algorithm is capable of efficiently solving the model of the generator start-up sequence after the blackout. Moreover, the F-DQN algorithm exhibits superior learning efficiency, faster convergence, and higher-quality optimal solutions compared to the DQN. This paper also discusses the applicability of this method under partial blackouts. When compared to other decision-making algorithms, the proposed method offers a restoration scheme that is both time-efficient and results in increased electricity generation. [ABSTRACT FROM AUTHOR]

Marine biofouling is an urgent global problem in the process of ocean exploitation and utilization. In our work, a series of zinc-based acrylate copolymers (ACZn-x) were designed and synthesized using benzoic acid, zinc oxide (ZnO) and a random quaternion copolymer consisting of ethyl acrylate (EA), butyl acrylate (BA), acrylic acid (AA) and methacrylic acid (MAA) by free radical polymerization and dehydration condensation. The ACZn-x with a zinc benzoate side chain is able to hydrolyze in natural seawater under static conditions, resulting in the formation of a smooth surface. We investigated and confirmed the antifouling (AF) behavior of ACZn-x in the laboratory and revealed that they have better antibacterial (86% for S. aureus and 72% for E. coli) and anti-algal (≥60.1% for N. closterium and ≥67.5% for P. subcordiformis) activities. We also assessed the marine AF properties of ACZn-x and corresponding coatings in Qingdao, China; the ACZn-x exhibited ideal AF properties with little silt and biological mucosa adhered to the ACZn-x surface after 6 months, and corresponding coatings exhibited little biofouling after 16 months in the ocean. Importantly, possible AF mechanisms were further proposed at the cellular level. These results could be helpful for the development and application of effective AF coatings. [ABSTRACT FROM AUTHOR]

In order to compare the compensation effect of expansive materials with different mineral sources on the temperature stress of concrete, we investigated the temperature stress of concrete when adding calcium sulfoaluminate type expansive materials (CSA) or CaO and calcium sulfoaluminate mixed type expansive materials (HCSA) at different temperatures by temperature-stress testing machine (TSTM) considering the influence of temperature history on the expansion. The experimental results show that the expansion characteristics of the two kinds of expansive materials with different mineral sources significantly vary. When adding expansive materials, the growth rate of compressive stress during the heating stage increases obviously, the maximum compressive stress is higher, while the decline rate of tensile stress in the late cooling stage becomes slow, and finally cracking temperature decreases. It is proved that concrete with HCSA has lower cracking temperatures and better temperature shrinkage compensation effect. Therefore, it is rational to choose HCSA when preparing concrete with high expansion energy to reduce thermal cracking. [ABSTRACT FROM AUTHOR]

Hydration-heat-inhibiting materials(HIM) with polysaccharide as core material was prepared using microcapsule sustained-releasing technology, through a centrifugal spray granulation process after melting together. The preparation process parameters of HIM were selected by the semi-adiabatic temperature rise test of cement paste. TAM air microcalorimeter was used to investigate the regulation performance of HIM on the hydration of cement. The influence of HIM on the microstructure of cement was investigated by XRD, SEM, and TG-DSC.The results showed that the most suitable wall material for HIM was polyethylene wax, the optimum polyethylene wax/polysaccharide mass ratio was 1, and the most effective particle size was 0.16–0.30 mm. Polysaccharide coated by polyethylene wax released slowly, and the peak heat release rate of cement could be reduced by 55.2% after continuous regulaion. The regulation period continued to 120 h. HIM mainly decreased the C3S reaction rate, which resulted in a 39.2% peak value reduction of hydration heat release rate. However, HIM had little regulation on C3A. The hydration heat release process of cement-based materials can be designed by adjusting the dosage of HIM. [ABSTRACT FROM AUTHOR]

In 3D frequency domain seismic forward and inversion calculation, the huge amount of calculation and storage is one of the main factors that restrict the processing speed and calculation efficiency. The frequency domain finite-difference forward simulation algorithm based on the acoustic wave equation establishes a large bandwidth complex matrix according to the discretized acoustic wave equation, and then the frequency domain wave field value is obtained by solving the matrix equation. In this study, the predecessor's optimized five-point method is extended to a 3D seven-point finite-difference scheme, and then a perfectly matched layer absorbing boundary condition (PML) is added to establish the corresponding matrix equation. In order to solve the complex matrix, we transform it to the equivalent real number domain to expand the solvable range of the matrix, and establish two objective functions to transform the matrix solving problem into an optimization problem that can be solved using gradient methods, and then use conjugate gradient algorithm to solve the problem. Previous studies have shown that in the conjugate gradient algorithm, the product of the matrix and the vector is the main factor that affects the calculation efficiency. Therefore, this study proposes a method that transform bandwidth matrix and vector product problem into some equivalent vector and vector product algorithm, thereby reducing the amount of calculation and storage. [ABSTRACT FROM AUTHOR]

MucA and MucB are critical negative modulators of sigma factor AlgU and regulate the mucoid conversion of Pseudomonas aeruginosa. Previous studies have revealed that lipid signals antagonize MucA-MucB binding. Here we report the crystal structure of MucB in complex with the periplasmic domain of MucA and polyethylene glycol (PEG), which unveiled an intermediate state preceding the MucA-MucB dissociation. Based on the biochemical experiments, the aliphatic side chain with a polar group was found to be of primary importance for inducing MucA cleavage. These results provide evidence that the hydrophobic cavity of MucB is a primary site for sensing lipid molecules and illustrates the detailed control of conformational switching within MucA-MucB in response to lipophilic effectors. Tao Li et al. report crystal structure of MucA-MucB complex and identify a cavity region of MucB that binds PEG molecule. They further show that this hydrophobic cavity of MucB is a primary site for sensing lipid molecules and that lipid A stimulates MucB to release MucA for AlgW cleavage, helping to understand the regulation mechanism of alginate biosynthesis. [ABSTRACT FROM AUTHOR]

Key message : Using bulk segregant analysis (BSA) coupling with RNA-seq and DNA markers identified a potentially novel nitrogen-dependent lesion mimic gene Ndhrl1 on 2BS in wheat. Abstract: Lesion mimic (LM) refers to hypersensitive reaction-like (HRL) traits that appear on leaf tissue in the absence of plant pathogens. In a wheat line P7001, LM showed up on the leaves under the 0 g nitrogen (N) treatment, but disappeared when sufficient N was supplied, suggesting that LM is N-responsive and N dosage dependent. Using BSA strategy together with RNA-seq and DNA markers, we identified an N-dependent LM gene ( Ndhrl1) and mapped it to the short arm of chromosome 2B using an F recombinant inbred population developed from the cross of P7001 × P216. The putative gene was delimited into an interval of 8.1 cM flanked by the CAPS/dCAPS markers 7hrC9 and 7hr2dc14, and co-segregated with the dCAPS marker 7hrdc2. This gene is most likely a novel gene for LM in wheat based on its chromosomal location. Further analysis of RNA-seq data showed that plant-pathogen interaction, nitrogen metabolism, zeatin biosynthesis and plant hormone signal transduction pathways were significantly differentially expressed between LM and non-LM lines. [ABSTRACT FROM AUTHOR]

It has been demonstrated that dentin matrix protein 1 (DMP1) is an essential regulator in the formation of bone and tooth. In addition to the mineralized tissues, DMP1 is also expressed in the non-mineralized tissues such as kidney, brain and salivary glands. Some studies have shown that the expression of DMP1 is significantly elevated in cancerous glands, while details about the expression and localization patterns of DMP1 in these glandular tissues still remain largely unknown. In this study, with multiple approaches, we systematically analyzed the expression and localization of DMP1 in mouse submandibular glands (SMGs). The results showed that although DMP1 was expressed in both female and male mouse SMGs, the mRNA levels of DMP1 in male mice were higher than those in female mice after the appearance of granular convoluted tubule (GCT). In mouse SMGs, DMP1 was primarily present as the 46 kDa C-terminal fragment and the 37 kDa N-terminal fragment. The C-terminal fragment was mainly localized in the nuclei of acinar and ductal cells, while the N-terminal fragment was restricted to the cytoplasm of ductal cells. This study showed the expression of DMP1 in the GCT of male mice, a novel finding different from the result of previous reports. Collectively, the differential localization patterns of DMP1 fragments indicate that different forms of DMP1 may play distinct roles in the SMGs. [ABSTRACT FROM AUTHOR]

A series of novel α,ω-bis(4-methylphenoxy) alkane functionalized cyclen ligands were synthesized by the nucleophilic substitution reaction of 1,4,7-tris( tert-butyloxycarbonyl)-1,4,7,10-tetraazacyclododecane and α,ω-bis(4-bromomethylphenoxy) alkanes. The corresponding dimeric Zn(II)-cyclen complexes were obtained by reaction of these ligands with Zn(ClO)·6HO. Ligands and complexes were characterized by FT-IR, H NMR, and elemental analysis. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the efficacy of changes in enhancement pattern in assessing no-surgical treatment response in bronchogenic carcinoma preliminarily. Methods: Thirty-three patients with bronchogenic carcinoma underwent two-phase contrast material-enhanced computed tomography prior to and after stopping no-surgical treatment more than one-month respectively. Two spiral CT scans were obtained at 25 and 90 s respectively after nonionic contrast material was administrated via the antecubital vein at a rate of 3 mL/s by using an autoinjector. The sum of the tumor longest diameters (LD) prior to treatment, after treatment and the sum of the post-treatment tumor enhancement area LD on the images obtained at 90 s after injection of contrast medium were recorded. Precontrast and postcontrast attenuation on every scan was recorded and peak height was calculated. The significance of the difference among groups was analyzed by means of ANOVA, student t test and chi-square test. Results: The sum of the tumor LD prior to treatment, that of after treatment and the sum of the post-treatment tumor enhancement area LD on the images obtained at 90 s after injection of contrast medium were (4.49 ± 1.32), (4.05 ± 1.63), (3.36 ± 1.22) cm respectively and there were statistically significant differences among them ( f = 5.467, P = 0.006). The sum of the tumor LD prior to treatment was significantly higher than that of the post-treatment tumor enhancement area ( P = 0.001). No statistically significant difference in the sum of the tumor LD was found between the pre-treatment and the post-treatment ( P = 0.207). There was no statistically significant difference between the sum of the tumors LD and that of tumor enhancement area after treatment ( P = 0.086). The response rate (RR) (21.21%) according to changes in sum of the tumor LD was significantly lower than that (30.30%) according to changes in the sum of the post-treatment tumor enhancement area LD (χ = 15.12, P < 0.05), and the progressive diseases (PD) rate (21.21%) was significantly higher than that (12.12%; χ = 14.12, P < 0.05). No statistically significant difference was found between precontrast attenuation prior to treatment [(41.77±7.03) HU] and that after treatment [(41.89 ±7.63) HU; t = 0.335, P = 0.740 > 0.05]. Peak height of bronchogenic carcinoma prior to treatment [(36.50 ± 11.21) HU] were significantly higher than that after treatment [(29.91 ± 10.35) HU; t = 10.081, P = 0.001]. Conclusion: Therapeutic effect may be underestimated with use of changes in sum of the tumor LD. The changes in sum of tumor enhancement area LD in addition to peak height is suggested to be used in assessing no-surgical treatment response in bronchogenic carcinoma. [ABSTRACT FROM AUTHOR]

Objective: The aim of our study was to determine an optimal slice thickness that was efficient in revealing bronchial imageology of pulmonary nodules (PNs) on multi-slice spiral computed tomography (MSCT) images preliminarily. Methods: Fifty-four patients with 62 PNs (diameter ≤ 3 cm) underwent multidetector-row computed tomography of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 0.625 mm. Three sets of contiguous images were reconstructed with 1-, 2-, and 5-mm slice thickness, respectively. Bronchial imageology of SPNs on the CT images presented in 1-, 2-, and 5-mm slice thickness was compared. Using the 1-mm sections as the gold standard, an optimal slice thickness in revealing bronchial imageology of PNs was determined. Results: Bronchial imageology of PNs on the CT images presented in 1 mm slice thickness involved 85 bronchi (35 second-fourth generation bronchi; 50 fifth-eighth generation bronchi). Bronchial imageology on 2-mm-thick sections was as same as that on 1-mm-thick sections in 34 second-fourth generation bronchi. No statistically significant difference in number of second-fourth generation bronchi with same bronchial imageology was found between that on 2-mm-thick images and 1-mm-thick images ( P = 0.836 > 0.05). Bronchial imageology on 5-mm-thick sections was as same as that on 1-mm-thick sections in 24 second-fourth generation bronchi. There was statistically significant difference in number of second-fourth generation bronchi with same bronchial imageology between that on 5-mm-thick images and 1-mm-thick images ( P = 0.026 < 0.05). Bronchial imageology on 2-mm-thick sections was as same as that on 1-mm-thick sections in 38 fifth-eighth generation bronchi. There was statistically significant difference in number of fifth-eighth generation bronchi with same bronchial imageology between that on 2-mm-thick images and 1-mmthick images ( P = 0.029 < 0.05). Bronchial imageology on 5-mm-thick images was as same as that on 1-mm-thick images in 31 fifth-eighth generation bronchi. There was statistically significant difference in number of fifth-eighth generation bronchi with same bronchial imageology between that on 5-mm-thick sections and 1-mm-thick sections ( P = 0.001 < 0.05). Conclusion: It is suggested that the use of 2-mm slice thickness is suitable in revealing second-fourth generation bronchi and the use of 1-mm slice thickness is suitable in revealing fifth-eighth generation bronchi. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine an optimal slice thickness that was efficient in revealing lobulation of malignant solitary pulmonary nodules (SPNs) on multi-slice spiral computed tomography (MSCT) images preliminarily. Methods: Fifty patients with malignant SPNs (diameter ≤ 3 cm) underwent multidetector-row computed tomography of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 0.625 mm. Three sets of contiguous images were reconstructed with 1-, 2-, and 5-mm slice thickness, respectively. The lobulation sign of SPNs on the computed tomography (CT) images presented in 1-, 2-, and 5-mm slice thickness was compared. Using the 1-mm sections as the gold standard, an optimal slice thickness in revealing lobulation sign of SPNs was determined. Results: The 1-mm-thick images CT revealed 98 lobulations (25 with chord distance < 1 mm; 30 with chord distance 1-2 mm; 43 with chord distance > 2 mm) of 45 malignant SPNs. 18 lobulations with chord distance < 1 mm presented in 2-mm-thick sections were as same as those in 1-mm-thick sections. Statistically significant difference in lobulations number was found between that revealed in 2-mm-thick images and that in 1-mm-thick images ( P = 0.023 < 0.05). 16 lobulations with chord distance < 1 mm presented in 5-mm-thick sections were as same as that in 1-mm-thick sections. There was statistically significant difference in lobulations number between that revealed in 5-mm-thick images and that in 1-mm-thick images ( P = 0.004 < 0.05). The 24 lobulations with chord distance 1-2 mm presented in 2-mm-thick sections were as same as that in 1-mm-thick sections. No statistically significant difference in lobulations number were found between that revealed in 2-mm-thick images and that in 1-mm-thick images ( P = 0.261 > 0.05). 13 lobulations with chord distance 1-2 mm presented in 5-mm-thick sections were as same as that in 1- mm-thick sections. There was statistically significant difference in lobulations number between that revealed in 5-mm-thick images and that in 1-mm-thick images ( P = 0.003 < 0.05). 40 lobulations with chord distance s>2 mm presented in 2-mm-thick sections were as same as that in 1-mm-thick sections. No statistically significant difference in lobulations number was found between that revealed in 2-mm-thick images and that in 1-mm-thick images ( P = 0.631 > 0.05). 36 lobulations with chord distance >2 mm presented in 5-mm-thick sections were as same as that in 1-mm-thick sections. There was no statistically significant difference in lobulations number between that revealed in 5-mm-thick images and that in 1-mm-thick images ( P = 0.264 > 0.05). Conclusion: It is suggested that the use of 1-mm slice thickness is suitable in revealing lobulations with chord distance < 1 mm. A 2-mm slice thickness is suggested to be used in revealing lobulations with chord distance 1-2 mm and 5-mm slice thickness to be used in revealing lobulations with chord distance > 2 mm. [ABSTRACT FROM AUTHOR]