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We propose an efficient version of ensemble Hartree–Fock/density functional theory to calculate a set of two charge-transfer states for systems with odd-numbers of electrons. The approach does require definitions of donor/acceptor fragments; however, the approach is not very sensitive to such definitions—even in the limit of very strong electronic coupling. The key ansatz is that, by mandating that the vector space spanned by the active orbitals projects equally onto the donor and acceptor fragments, such a constraint eliminates all intra-molecular local excitations and makes it far easier to generate potential energy surfaces that are smooth over a wide region of configuration space. The method is fast, working with only two electron configurations, and should be useful for ab initio non-adiabatic dynamics in the near future. [ABSTRACT FROM AUTHOR]

Within the context of fewest-switch surface hopping (FSSH) dynamics, one often wishes to remove the angular component of the derivative coupling between states J and K . In a previous set of papers, Shu et al. [J. Phys. Chem. Lett. 11, 1135–1140 (2020)] posited one approach for such a removal based on direct projection, while we isolated a second approach by constructing and differentiating a rotationally invariant basis. Unfortunately, neither approach was able to demonstrate a one-electron operator O ̂ whose matrix element J O ̂ K was the angular component of the derivative coupling. Here, we show that a one-electron operator can, in fact, be constructed efficiently in a semi-local fashion. The present results yield physical insight into designing new surface hopping algorithms and are of immediate use for FSSH calculations. [ABSTRACT FROM AUTHOR]

Modern electronic structure theory is built around the Born–Oppenheimer approximation and the construction of an electronic Hamiltonian H ̂ e l (X) that depends on the nuclear position X (and not the nuclear momentum P). In this article, using the well-known theory of electron translation (Γ′) and rotational (Γ″) factors to couple electronic transitions to nuclear motion, we construct a practical phase-space electronic Hamiltonian that depends on both nuclear position and momentum, H ̂ P S (X , P). While classical Born–Oppenheimer dynamics that run along the eigensurfaces of the operator H ̂ e l (X) can recover many nuclear properties correctly, we present some evidence that motion along the eigensurfaces of H ̂ P S (X , P) can better capture both nuclear and electronic properties (including the elusive electronic momentum studied by Nafie). Moreover, only the latter (as opposed to the former) conserves the total linear and angular momentum in general. [ABSTRACT FROM AUTHOR]

Archaeological discoveries and historical documents show that the Chengdu Plain was the most important iron production center in the southwest region of China during the Qin and Han dynasties. However, due to the lack of archaeological evidence, the iron production technology of cities in the Chengdu Plain during the Qin and Han dynasties remains unclear. The Xindu city site is located in Qingbaijiang District, Chengdu Sichuan Province. It was an important city site in the Chengdu Plain during the Han and Jin dynasties. During excavation of the Xindu city site, archaeologists unearthed a large number of metallurgical remains such as slags and tuyeres, as well as two severely damaged hearth bases near the western city wall. Scientific analysis results suggest that the metallurgical remains are related to the steel fining process and could be dated back to the Western Han Dynasty. The metallurgical remains in the Xindu city are the earliest known artifacts associated with the steel fining process in southwest China. This discovery also marks the first identification of iron industry workshops in a Han Dynasty city in the Chengdu Plain. The findings reveal a different industrial layout pattern from previously discovered Han Dynasty metallurgical sites in the Chengdu Plain. Additionally, this discovery provides archaeometallurgical evidence for the central government's development in southwest China during the Han Dynasty. [ABSTRACT FROM AUTHOR]

Metalized film capacitors in a.c. applications suffer high frequency and high voltage, which will induce electrode corrosion, leading to capacitance degradation. The intrinsic mechanism of the corrosion is oxidation caused by ionic migration in the oxide film formed on the electrode surface. In this work, a D–M–O illustration structure for the nanoelectrode corrosion process is established, and thereby, an analytical model is derived to study the influences of frequency and electric stress on corrosion speed in a quantitative approach. The analytical results well conform to the experimental facts. It is found the corrosion rate rises with frequency and finally tends to reach a saturation value. The electric field in oxide has an exponential-like contribution to the corrosion rate. In the case of aluminum metalized films, the saturation frequency and minimum field required for corrosion initiation are, respectively, 3434 Hz and 0.35 V/nm calculated by the proposed equations. [ABSTRACT FROM AUTHOR]

This paper conducts the analytical investigation on the buckling of cylindrical shells with axially variable elastic modulus subjected to axial compressive load for the first time. First, it proves that the axially distributed elastic modulus can be expressed as the combination of constant and variable component. Then, governing differential equations for buckling analysis are derived and exactly solved by the combined perturbation method and Fourier analysis. Accordingly, the closed analytical solutions for the cylinder with arbitrarily variable elastic modulus are obtained, which reveal the explicit relations among buckling load, shell sizes and elastic modulus functions. Based on the presented analytical formulas, four types of elastic modulus variations for shell material which are uniform, periodic, linear and combined are studied in detail, and the results are also well verified. The derived analytical solutions in this paper can serve as benchmarks for buckling analyses of thin-walled cylinders with elastic modulus variations resulted from design, material manufacturing process, material imperfections and so on. [ABSTRACT FROM AUTHOR]

School bullying among primary and secondary school students has received increasing attention, and identifying relevant factors is a crucial way to reduce the risk of bullying victimization. Machine learning methods can help researchers predict and identify individual risk behaviors. Through a machine learning approach (i.e., the gradient boosting decision tree model, GBDT), the present longitudinal study aims to systematically examine individual, family, and school environment factors that can predict the risk of bullying victimization among primary and secondary school students a year later. A total of 2767 participants (2065 secondary school students, 702 primary school students, 55.20% female students, mean age at T1 was 12.22) completed measures of 24 predictors at the first wave, including individual factors (e.g., self-control, gender, grade), family factors (family cohesion, parental control, parenting style), peer factor (peer relationship), and school factors (teacher–student relationship, learning capacity). A year later (i.e., T2), they completed the Olweus Bullying Questionnaire. The GBDT model predicted whether primary and secondary school students would be exposed to school bullying after one year by training a series of base learners and outputting the importance ranking of predictors. The GBDT model performed well. The GBDT model yielded the top 6 predictors: teacher–student relationship, peer relationship, family cohesion, negative affect, anxiety, and denying parenting style. The protective factors (i.e., teacher–student relationship, peer relationship, and family cohesion) and risk factors (i.e., negative affect, anxiety, and denying parenting style) associated with the risk of bullying victimization a year later among primary and secondary school students are identified by using a machine learning approach. The GBDT model can be used as a tool to predict the future risk of bullying victimization for children and adolescents and to help improve the effectiveness of school bullying interventions. [ABSTRACT FROM AUTHOR]

To effectively suppress the longitudinal vibration of the car under the conditions of high-speed operation and emergency braking, and improve the ride comfort of the car system, this paper proposes an adaptive fuzzy inverse optimal output feedback control strategy. Firstly, the dynamic model of the high-speed elevator system is established and the nonlinear dynamic model is approximated by the fuzzy logic system, and the auxiliary system model is established. Fuzzy state observer is designed to estimate the unmeasurable state. Furthermore, an adaptive inverse optimal output feedback controller based on fuzzy observer is designed by using adaptive backstepping technology and inverse optimal control principle. The stability analysis shows that the proposed adaptive fuzzy inverse optimal output feedback control strategy not only ensures the stability of the car attitude of high-speed elevator but also realizes the inverse optimization of the target cost function. Finally, the acceleration time–frequency response analysis of the two typical stages of high-speed elevator uniform running and emergency braking is carried out, and the numerical results are compared with the linear quadratic controller optimized by stepping quantum genetic algorithm (GA-LQR) and controller based on the state-dependent Ricatti equation (SDRE). The analysis verifies the effectiveness of the controller. [ABSTRACT FROM AUTHOR]

We show that the Berry force as computed by an approximate, mean-field electronic structure can be meaningful if properly interpreted. In particular, for a model Hamiltonian representing a molecular system with an even number of electrons interacting via a two-body (Hubbard) interaction and a spin–orbit coupling, we show that a meaningful nonzero Berry force emerges whenever there is spin unrestriction—even though the Hamiltonian is real-valued and formally the on-diagonal single-surface Berry force must be zero. Moreover, if properly applied, this mean-field Berry force yields roughly the correct asymptotic motion for scattering through an avoided crossing. That being said, within the context of a ground-state calculation, several nuances do arise as far interpreting the Berry force correctly, and as a practical matter, the Berry force diverges near the Coulson–Fischer point (which can lead to numerical instabilities). We do not address magnetic fields here. [ABSTRACT FROM AUTHOR]

Identifying high‐efficiency photocatalysts for producing hydrogen peroxide from H2O and O2 is a promising yet challenging research direction for achieving solar‐to‐chemical energy conversion and storage. Herein, 14 experimentally feasible 2D covalent triazine/heptazine‐based frameworks (CTFs/CHFs) are constructed with phosphorus‐alkynyl/phosphorus‐alkynyl‐phenyl functional moieties through topological assembly and four promising visible‐light‐driven photocatalysts for H2O2 production from H2O and O2 via first‐principles computations are filtered out: CTF‐1 based on triazine and phosphorus‐acetylene, CTF‐2 based on triazine and phosphorus‐diacetylene, CHF‐1 based on heptazine and phosphorus‐acetylene, and CHF‐2 based on heptazine and phosphorus‐diacetylene. The computational results show that introducing electron‐rich phosphorus‐alkynyl moieties into CTFs/CHFs can effectively modulate their electronic structures, provide sufficient driving force for water oxidation, and facilitate O2 adsorption and activation, thereby significantly boosting the overall photocatalytic process. Among them, CHF‐1 and CHF‐2 exhibit the highest photocatalytic activity for H2O2 production at pH 7, and their ideal solar‐to‐chemical conversion (SCC) efficiency for H2O2 generation are theoretically estimated to be 26.06% and 35.37%, respectively, implying their great promise as photocatalysts for industrialized production of H2O2. The work presents a promising way for rationally designing and developing novel photocatalysts for H2O2 production, and provides new inspiration and reference for experimental research in this field. [ABSTRACT FROM AUTHOR]

The Jiangkou site is located in the Min River channel in Pengshan County, Sichuan Province, China. One hundred and four bronze weapons and tools of the First millennium to the second century BCE were found throughout five excavations from 2016 to 2022. Typology and radiocarbon dating suggest that the bronze objects could be dated as early as the early Western Zhou dynasty. There is a great variety of object types, and some types have not been discovered before. In order to study the technical characteristics and the sources of raw materials of these bronze objects, through analysis of observation of the wood handles in the socket of the axes and alloy composition, we found that the wood handles were most likely sourced locally, and the people at that time consciously chose tree species suitable for tool and agricultural implement handles. Compositional analysis shows that Jiangkou bronzes have diachronic differences in alloy compositions, Western Zhou bronzes exhibited the highest copper content, with lower lead and tin content, but the copper content in the bronzes of the Eastern Zhou dynasty declined significantly, while lead and tin content increased to varying degrees. Furthermore, the alloy compositions of the Jiangkou bronzes were directly related to their forms and functions. The lead isotope study indicates that the copper materials used in the Western Zhou bronzes from Jiangkou were found to be diverse, including both Central Plains-type materials and local materials. Moreover, six bronzes displayed highly radiogenic lead. Compared with the Western Zhou bronzes, the lead isotope ratios of Eastern Zhou bronzes from Jiangkou site are more concentrated, some of the copper used in Eastern Zhou bronzes may have originated from local sources in Sichuan. Through scientific analysis, this research provides new understandings and a new perspective for the study of early bronzes in the Chengdu Plain. [ABSTRACT FROM AUTHOR]

Three-dimensional thermal-mechanical analytical solutions to the elastic half-space pressed by an inclined rigid cylindrical structure are presented in this article for the first time, based on the recent thermo-elastic general solutions in terms of harmonic functions and potential theory method. The obtained solutions are proved to be closed. The adequate validations are provided by comparing contact displacement and contact pressure on the contact plane from the presented solutions with those without heat effect in literatures. The geometric distribution of temperature on the contact region is also in accordance with that by previous researcher for the composite material under uniform heat flux. In addition, for the purpose of engineering application, a numerical example which is thermal contact problem between an inclined rigid circular displacement restrictor and elastic half-space is given, and the distributions of key field variables and effects of heat flux on contact pressure and normal displacement are discussed in detail. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to investigate the clinical and molecular differences between diffuse large B-cell lymphoma (DLBCL) patients with MYD88L265P and MYD88other. Methods: DLBCL patients with MYD88 variations were collected from the Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College (CHCAMS), and Suzhou Municipal Hospital from February 6th, 2007 to May 20th, 2022. Clinicopathological parameters and treatment outcomes between MYD88L265P and MYD88other were investigated. Results: A total of 132 patients with MYD88 variations from a cohort of 475 DLBCL patients were included, among which, 78 were MYD88L265P, while 54 were MYD88other. MYD88L265P was more common in non-GCB subtype than MYD88other (83% vs. 60%, P = 0.004). Besides, MYD88L265P was significantly related to higher proportion of testicle/ central nervous system involvement (31% vs. 6%, P < 0.001), PIM1 mutation (71% vs. 39%, P < 0.001), and PIM1 hypermutation (28% vs. 11%, P = 0.018), compared with MYD88other. Compared with MYD88L265P, MYD88other were more likely to have higher percentage of advanced stage (60% vs. 42%, P = 0.044), extranodal site ≥ 2 (45% vs. 28%, P = 0.044), elevated LDH (55% vs. 35%, P = 0.033), positive CD10 expression (36% vs. 16%, P = 0.009), BCL-6 translocation (20% vs. 8%, P = 0.033), and NOTCH pathway gene alteration (24% vs. 13%, P = 0.040). In non-GCB DLBCL subtype, patients with MYD88other were significantly associated with worse progression free survival (PFS) than those with MYD88L265P when treated initially with R-CHOP/R-CHOP-like regimen (P = 0.010). Conclusion: The findings of this study indicate that DLBCL patients with MYD88L265P and MYD88other are likely to be two subgroups with different clinical and molecular characteristics. The survival of patients with MYD88other is not superior than those with MYD88L265P, even poorer when focusing on the non-GCB subtype. [ABSTRACT FROM AUTHOR]

Microbiome-derived metabolites are important for the microbiome-gut-brain axis and the discovery of new disease treatments. d-Alanine (d-Ala) is found in many animals as a potential co-agonist of the N-methyl-d-aspartate receptors (NMDAR), receptors widely used in the nervous and endocrine systems. The gut microbiome, diet and putative endogenous synthesis are the potential sources of d-Ala in animals, although there is no direct evidence to show the distribution and racemization of gut-absorbed l-/d-Ala with regards to host-microbe interactions in mammals. In this work, we utilized germ-free mice to control the interference from microbiota and isotopically labeled l-/d-Ala to track their biodistribution and racemization in vivo. Results showed time-dependent biodistribution of gut-absorbed d-Ala, particularly accumulation of gut-absorbed d-Ala in pancreatic tissues, brain, and pituitary. No endogenous synthesis of d-Ala via racemization was observed in germ-free mice. The sources of d-Ala in mice were revealed as microbiota and diet, but not endogenous racemization. This work indicates the importance of further investigating the in vivo biological functions of gut-microbiome derived d-Ala, particularly on NMDAR-related activities, for d-Ala as a potential signaling molecules in the microbiome-gut-brain axis. The microbial metabolite, d-alanine, cannot be endogenously synthesized by mice, and is instead derived from the food and gut microbiota, with gut-absorbed d-alanine accumulating in the mouse pancreas, brain, and pituitary. [ABSTRACT FROM AUTHOR]

International Classification of Diseases (ICD) serves as the foundation for generating comparable global disease statistics across regions and over time. The process of ICD coding involves assigning codes to diseases based on clinical notes, which can describe a patient's condition in a standard way. However, this process is complicated by the vast number of codes and the intricate taxonomy of ICD codes, which are hierarchically organized into various levels, including chapter, category, subcategory, and its subdivisions. Many existing studies focus solely on predicting subcategory codes, ignoring the hierarchical relationships among codes. To address this limitation, we propose a multitask learning model that trains multiple classifiers for different code levels, while also capturing the relations between coarser and finer-grained labels through a reinforcement mechanism. Our approach is evaluated on both English and Chinese benchmark dataset, and we demonstrate that our method achieves competitive performance with baseline models, particularly in terms of macro-F1 results. These findings suggest that our approach effectively leverages the hierarchical structure of ICD codes to improve disease code prediction accuracy. Analysis of attention mechanism shows that multigranularity attention of our model captures crucial feature of input text on different granularity levels, which can provide reasonable explanations for the prediction results. [ABSTRACT FROM AUTHOR]

In this paper, a pioneering study of the electronic and optical properties of QPHT-graphene after adsorbing three types of alkali metal atoms (Li/Na/K) was conducted using first-principles calculations based on density functional theory. The electronic properties study covers TDOS, PDOS, and Bader charge analyses, in addition to charge density difference. The optical properties study considers the complex dielectric function, complex refractive function, absorption coefficient, reflection coefficient and energy loss function under three types of polarization. The results show that all configurations exhibit a good optical response within a wide energy range of 0–25 eV and are anisotropic under all three polarization types. Under E x and E y polarizations, the adsorption of alkali metal atoms significantly enhances the absorptivity, reflectivity, and refractivity of the pristine QPHT-graphene. As the atomic number increases, it shows a regular oscillatory behavior. Under E z polarization, the QPHT-graphene optical response is concentrated in the high-frequency ultraviolet region, i.e., higher than 10 eV, and alkali metal atom adsorption has little effect on its optical properties. These results show that alkali metal atom adsorption can effectively modulate the optical properties of QPHT-graphene. This research can help to further understand the electronic and optical properties of QPHT-graphene and is instructive in promoting the application of new two-dimensional nanocarbon materials in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

An erratum has been issued for an article titled "On the meaning of Berry force for unrestricted systems treated with mean-field electronic structure." The mistake is in Equation (9), which should read as h1 = 0.1 tanh(x), h2 = -0.1 (tanh(x) - 1). However, this typo does not impact the conclusions of the article. The authors acknowledge the error and thank those who brought it to their attention. [Extracted from the article]

Cryogenic CO2-assisted minimum quantity lubrication milling technology is a green processing technology with broad application prospects. Aiming at the problem of tool wear in the application of cryogenic CO2-assisted minimum quantity lubrication in difficult-to-machine materials and the influence of relevant parameters on tool wear, this study used coated cemented carbide tools to perform milling experiments under cryogenic CO2-assisted minimum quantity lubrication technology conditions. The micro-morphology of the tool and chip was observed, and the energy spectrum of the tool chip contact area was analyzed. The results show that reducing CO2 temperature and increasing the oil flow of minimum quantity lubrication can improve the tool wear. The tool wear mechanisms under cryogenic CO2-assisted minimum quantity lubrication are mainly abrasive wear, diffusion wear, and oxidation wear. The chip sawtooth degree of the optimal parameter group is more conducive to chip breaking than that of dry-cutting and wet-cutting groups. The temperature of the tool-chip contact area is an important factor affecting tool wear; the higher the temperature, the faster the tool wear. At the same time, it is verified that cryogenic CO2-assisted minimum quantity lubrication technology can replace cutting fluid in hard-to-machine materials under certain conditions. [ABSTRACT FROM AUTHOR]

We analyzed the prognostic factors for treatment outcomes amongst 34 patients with adult Burkitt lymphoma (BL) who received rituximab with standard first-line chemotherapy. Seven patients had human immunodeficiency virus (HIV)-associated BL. Overall, we observed a complete remission (CR) rate of 91.2%, and 10-year progression-free survival (PFS) and overall survival (OS) was 84.8 and 88.2%, respectively. In patients with concomitant HIV, the prognosis was not different with 10-year PFS of 100% and OS of 88.2%. The majority (71.4%) of HIV-associated BL patients received dose-adjusted EPOCH-R (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab) and had excellent outcomes with 100% CR and no relapses. Central nervous system (CNS) disease, bone marrow involvement and elevated serum lactate dehydrogenase (LDH) levels more than 3 times upper limit of normal (ULN) were associated with poorer survival outcomes. Patients with refractory disease, whilst uncommon (n = 4), had dismal outcomes. Patients with adult BL, including HIV-related cases, harbor generally good prognosis in the modern era. [ABSTRACT FROM AUTHOR]

Jiangkou, China, is the battleground site where, in 1646, Zhang Xianzhong, the peasant uprising leader, fought against Yang Zhan, the general of the Southern Ming government. The fierce and powerful Zhang Xianzhong was defeated in this battle, and his enormous quantities of gold and silver objects sank to the bottom of the Min River. From archaeological excavations conducted from 2016 to 2020, the excavators have confirmed that Zhang Xianzhong's objects are dominated by gold and silver items, ingots, coins, and jewels. The discovery at the battleground of Jiangkou is important because almost all of the remains are firsthand historical materials that are useful in studying the politics, economy, and military affairs of the Ming dynasty during the 17th century. [ABSTRACT FROM AUTHOR]

An electric-liquid active guide shoe is designed to aim at the problem of car horizontal vibration caused by guide unevenness excitation. Considering the imprecision of system dynamic modeling caused by the change of load during high-speed elevator operation and the nonlinear factors of active guide shoe, the Takagi-Sugeno (T-S) fuzzy reasoning method is adopted to approximate the nonlinear car system model. Further, taking the car acceleration, displacement and actuator saturation as the controlled performance indexes, an adaptive gain H∞ output feedback control strategy is proposed based on the parallel distributed compensation rule (PDC) to attenuate the horizontal vibration of the car system. To illustrate the effectiveness of the controller and its robustness to load changes, the acceleration time-frequency response of 4 m/s high-speed elevator car system under light load and heavy load was analyzed, and compared with the numerical results under H2/H∞ robust control, It is further verified that the proposed H∞ output feedback controller with adaptive gain can effectively suppress the horizontal vibration of the high-speed elevator car system. [ABSTRACT FROM AUTHOR]

This paper analytically studies the buckling of a cylindrical shell having varying thickness under non-uniform axial compressive loads for the first time, which widely exists in engineering practice. A novel quadratic perturbation technique is developed to establish general buckling load formulas for the shell. This method overcomes the difficulties of traditional energy methods in solving high order determinants and deriving direct expressions for buckling loads when shell thickness and axial load are unknown. Applying presented formulas, various shell thicknesses and axial loads are analyzed, and a series of new results for buckling loads are obtained and validated. Even for classical cosine thickness variation under uniform axial compression, we also give general conclusions compared with Koiter's results by the energy method. The effects of thickness variations and load distribution parameters on buckling loads are analyzed in detail. The presented study in this paper fills the gap and establishes a foundation of buckling analysis for non-uniformly loading cylindrical shells with variable thickness. Certainly, the established formulas are general and available for buckling resistance capacity evaluation for the shells under all circumstances involving thickness variations or/and non-uniform axial compressive loads. [ABSTRACT FROM AUTHOR]

Background. Shu Gan Jie Yu (SGJY) capsule has a good effect on relieving depressive symptoms in China. However, the mechanism of action is still unclear. Therefore, systemic pharmacology and molecular docking approaches were used to clarify its corresponding antidepressant mechanisms. Methods. Traditional Chinese Medicine Database and Analysis Platform (TCMSP), the Encyclopedia of Traditional Chinese Medicine (ETCM), and Swiss Target Prediction servers were used to screen and predict the bioactive components of the SGJY capsule and their antidepressive targets. Mild to moderate depression (MMD) related genes were obtained from GeneCards and DisGeNET databases. A network of bioactive components-therapeutic targets of the SGJY capsule was established by STRING 11.5 and Cytoscape 3.9.0 software. Gene function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed by utilizing Database for Annotation, Visualization, and Integrated Discovery (DAVID) platform. Active components were taken to dock with the hypothetical proteins by iGEMDOCK and SwissDock, and the docking details were visually displayed by UCSF Chimera software. Then, the related research literature of the SGJY capsule was reviewed, summarized, sorted, and analyzed, including experimental evidence and clinical experience. Results. Seven active components and 45 intersection targets were included in the study. PPI network had genuinely uncovered the potential therapeutic targets, such as AKT1, HSP90AA1, ESR1, EGFR, and PTGS2. KEGG pathway analysis showed that the mechanism of the SGJY capsule on MMD was mainly involved in the PI3K-Akt signaling pathway. Conclusions. In this study, we have successfully predicted the biochemically active constituents, potential therapeutic targets, and comprehensively predicted the related drug-gene interaction of the SGJY capsule for treating MMD and provided a basis for subsequent experiments. [ABSTRACT FROM AUTHOR]

• The mechanical properties of nacreous structure exhibit significant anisotropy. • Nacreous structure loaded to different faces exhibits different fracture morphologies. • The different cracking modes play an essential role in anisotropy. • The critical parameters to characterize the anisotropy were proposed. Nacreous structure holds significant promise for biomimetic design applications due to its excellent mechanical properties. In this paper, the influence of loading direction on the mechanical properties of nacreous structure was investigated to understand its mechanisms of anisotropic fracture resistance. The results revealed significant anisotropy in the mechanical properties of nacre when loaded along different directions (perpendicular to y and z axes). When loaded perpendicular to the top face, nacre exhibits better mechanical properties and greater resistance to fracture compared to loading perpendicular to the side face. This distinction can be attributed to different cracking modes of organic interfaces in nacreous structure, where the nacreous structure loaded perpendicular to the top face exhibits more tortuous crack deflection, larger fracture stepped surface area and microcrack zones. Furthermore, the theoretical analysis indicates that the differences in the volume fraction of organic interfaces and the main crack deflection along organic interfaces are important factors leading to different cracking modes of organic interfaces in nacreous structure. Based on the analysis of the mechanisms of anisotropic fracture resistance, the critical parameters to characterize the anisotropic mechanical properties of the nacreous structure were proposed. The research results provide a reference and basis for future biomimetic application design. [ABSTRACT FROM AUTHOR]

• Neural network regularization is completed using wall temperature first-order derivative as prior knowledge to reduce the ill-posedness of inverse heat transfer problem. • The RBF + BP approximation method with uncertain regularization coefficient is proposed. • The heat flux relative error can be reduced by 1 ∼ 2 orders of magnitude compared with several traditional data fitting methods. • The demand for measurement points can be reduced by approximately 44 ∼ 60 % compared with Bayesian inference method. Solving the heat conduction equation using surface measurement temperature as boundary conditions to obtain surface heat flux is an ill-posed inverse heat transfer problem, in which small temperature errors can create large uncertainties in heat flux. This paper proposes a RBF (Radial Basis Function) + BP (Back Propagation) neural network approximation method that uses the wall temperature characteristics as priori knowledge to reduce the ill-posedness of the inverse heat transfer problem in rotating disc cavities of aero-engines. The wall temperature characteristics are described using first-order derivative, which are discussed and obtained through analytical solution and fluid-thermal coupling numerical simulation. Bayesian inference theory is used to construct neural network training objective function with regularization term and the RBF + BP neural network approximation method with uncertain regularization coefficient is proposed. Numerical experiments were conducted based on numerical simulation data to verify the effectiveness of the proposed method. The results show that the method can effectively suppress the ill-posed nature of the inverse heat transfer problem and can reduce the heat flux relative error level by 1 ∼ 2 orders of magnitude compared with several traditional data fitting methods commonly used in rotating disc cavities. The method of densifying measurement points combined with priori knowledge revision near the air impact point can effectively capture the local heat flux characteristics caused by airflow impact. The RBF + BP approximation method can reduce the demand for measurement points by approximately 44 ∼ 60 % under the error of 3 σ = 0 K ∼ 0.9 K compared with Bayesian inference method. [ABSTRACT FROM AUTHOR]

In the two-dimensional heat transfer experiments of aero-engine rotating disk cavities, the inverse heat transfer problem method can be used to obtain the wall heat flux numerically, which uses the two-dimensional measured wall temperature to solve the rotating disk heat conduction equation. A back propagation (BP) neural network data approximation method is proposed to reduce the ill-posedness of the two-dimensional inverse heat transfer problems in rotating disk cavities in this paper. The priori knowledge of wall temperature characteristics expressed by two-dimensional wall temperature first-order radial partial derivative distribution is used for BP neural networks' regularization. The distribution characteristics of the wall temperature first-order radial partial derivative in a typical preswirl rotating disk cavity were investigated by the flow-thermal coupling numerical simulation. Based on these characteristics, the BP neural network construction and training method with uncertain regularization coefficient is adopted. The numerical experiment results show that compared with the traditional polynomial fitting methods, the BP neural network approximation methods in this paper show significant advantages in data processing performance and stability; The fluctuation amplitude of the wall heat flux relative error on the disk surface can be reduced by 1–3 orders of magnitude, reducing the relative error of wall heat flux in most areas of the disk to within 20 % of the original value; The maximum wall heat flux relative error suppression area where | δq r ,cal / δq r ,mea × 100 %| < 100 % of BP neural network approximation method can reach 1.93 times that of the traditional fitting method, and 3.18 times for the area where | δq r ,cal / δq r ,mea × 100 %| < 30 % in the current study. • Wall temperature first-order radial partial derivative priori knowledge is used for BP neural network regularization. • The construction and training method of BP neural network with uncertain regularization coefficient is proposed. • The two-dimensional heat flux relative error fluctuation amplitude can be reduced by 1–3 orders of magnitude. • BP neural network shows significant advantages in data processing effect and stability compared with polynomial fitting. [ABSTRACT FROM AUTHOR]

• CHO cytotoxicity of HKs were comparable with other priority aliphatic DBPs. • HK cytotoxicity followed the order of mono- > di- > tri-haloHKs. • HKs in drinking water samples of South Carolina and Suzhou were 12.4 and 0.9 µg/L. • HKs contributed about 14% of ovearll drinking water cytotoxicity of South Carolina. Although unregulated aliphatic disinfection byproducts (DBPs) had a much higher concentration and cytotoxicity than known aromatic DBPs, a recent study indicated that seven classes of regulated and unregulated priority DBPs (one and two-carbon-atom DBPs) just accounted for 16.2% of disinfected water cytotoxicity in the U.S., meaning some of the highly toxic aliphatic DBPs may be overlooked. Haloketones (HKs) are an essential class of priority DBPs with a 1–100 µg/L concentration in drinking water but lack cytotoxicity data. This study investigated the cytotoxicity of seven HKs using Chinese hamster ovary (CHO) cells. The order for cytotoxicity of HKs from most to least toxic was: 1,3-dichloroacetone (LC 50 : 1.0 ± 0.20 μM) ≈ 1,3-dibromoacetone (1.5 ± 0.19 μM) ≈ bromoacetone (1.9 ± 0.49 μM) > chloroacetone (4.3 ± 0.22 μM) > 1,1,3-trichloropropanone (6.6 ± 0.46 μM) > 1,1,1-trichloroacetone (222 ± 7.7 μM) > hexachloroacetone (3269 ± 344 μM). The cytotoxicity of HKs was higher than most regulated and priority aliphatic DBPs in mono-halogenated, di-halogenated, and tri-halogenated categories. A prediction model of HK cytotoxicity was developed based on the quantitative structure-activity relationship (QSAR), optimizing structures and computing descriptors with Gaussian 09 W. The average concentrations of HKs in representative drinking water samples from South Carolina (U.S.) and Suzhou (China) were 12.4 and 0.9 μg/L, respectively, accounting for 18.8% and 1.7% of their specific total DBPs measured (i.e. not TOX). For South Carolina drinking water, their contributions to total calculated additive cytotoxicity of aliphatic DBPs and overall drinking water cytotoxicity were 86.7% and 14.0%, respectively, demonstrating that HKs are an essential class of overlooked DBPs with a high contribution to drinking water cytotoxicity. Our study can help to explain the conflict that why regulated and priority DBPs (except HKs) just accounted for 16% of chlorinated drinking water cytotoxicity even enough they had much higher concentration and cytotoxicity than known aromatic DBPs. [Display omitted] [ABSTRACT FROM AUTHOR]

Size effect refers to alterations in material properties as their size varies, garnering significant attention as a cutting-edge issue. Graphite sheets, known for their exceptional thermal and electrical conductivity, the thickness effect on their mechanical properties is a notable gap in research. In this paper, the tensile strength, damage rate, and micro-fracture mechanism of graphite sheets with different thicknesses were studied through uniaxial tensile, digital image correlation (DIC) tests, and scanning electron microscope (SEM). The results reveal a significant thickness effect on the tensile strength of graphite sheets: thinner graphite sheets exhibit higher tensile strength and greater resistance to tensile fracture. Additionally, the thickness effect on the tensile strength was elucidated through the modified Weibull scaling law and Bažant size effect law. The thickness effect on the damage rate was revealed through strain evolution measured by DIC and the damage model. Thicker graphite sheets exhibit a more accelerated damage rate. It is noteworthy that the different fracture modes of layered structures are a crucial factor affecting the thickness effect of graphite sheets. Thinner graphite sheets exhibit more layers of stepped-like fracture, longer crack length, and a higher critical energy release rate. This study provides valuable insights for choosing the appropriate thickness of graphite sheets in practical applications and has the potential to enhance the safety performance of devices employing graphite sheets. [Display omitted] [ABSTRACT FROM AUTHOR]

• Silicon nanowires were in-situ grown on basalt fibers via chemical vapor deposition. • Tensile force of basalt fiber monofilament was enhanced by 19.0% after modification. • Interfacial shear strength between basalt fiber and epoxy was increased by 18.5%. In this work, the interface interaction between basalt fiber (BF) and epoxy resin (EP) is improved using the in-situ growth of polysiloxane nanowires (SiNWs) on the BF surface. First, the pristine BFs were treated by piranha solution to obtain numerous active hydroxyl groups. Subsequently, the hydrolysis of ethyl trichlorosilane (ETCS) under varying humidity facilitated the formation of self-assembled silanols, resulting in the stable one-dimensional nanostructure on the BF through chemical vapor deposition (CVD) for different durations. The results show the significance of both the humidity level during ETCS hydrolysis and deposition time in achieving the in-situ growth of SiNWs on BF. Furthermore, the effects of surface modification on BF strength and BF-EP interface adhesion were investigated. At a relative humidity of 62% and a deposition time of 4 h, the tensile force of BF monofilament and interfacial shear strength (IFSS) between BF and EP were enhanced by 19.0% and 18.5% respectively. [ABSTRACT FROM AUTHOR]

This retrospective study aimed to evaluate clinical outcomes of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR). MCDA twins, either sIUGR and non-sIUGR, underwent expectant management from 2016 to 2019 in our hospital were included. sIUGR fetuses were classified into three types according to umbilical artery Doppler assessment. Non-sIUGR were considered as the control group. Outcomes were pregnancy outcomes and maternal complications. Forty-three sIUGR (type I: 23; type II: 14, and type III: 6) and 282 non-sIUGR fetuses were included. The sIUGR group had a significantly earlier birth, lower birth weight of the twins, larger inter-twin weight difference, lower Apgar score of the twins, and higher intrauterine fetal death (IUFD) than the non-sIUGR group (all p < 0.001). The same trend was found in the sIUGR type II group compared to type I and III groups. A significantly lower gestational diabetes rate (p = 0.01) and placenta weight (p < 0.001), and higher proportions of abnormal placental umbilical cord insertion (p < 0.001), and ultrasound Doppler monitoring indicators (p = 0.006) were found in the sIUGR group than the non-sIUGR group. The MCDA twins with sIUGR showed poorer outcomes than the non-sIUGR group. Doppler interrogation was a useful clinical marker for fetal outcome. • Predicting and reducing earlier birth, fetal and neonatal deaths are crucial for MCDA sIUGR twins. • Doppler investigation of blood flow can serve as a predictor of outcomes for MCDA sIUGR twins. • Ultrasound diagnosis of fetal blood flow indicates neonatal prognosis or early delivery for MCDA sIUGR twins. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developed a method based on LLE-SPE and GC–MS/MS to determine POCPs in human serum. • Improved extraction efficiency and reduced ME with optimized sample pretreatment. • GC–MS/MS exhibited high sensitivity and was cost-effective compared with HRMS. • The method is ideal for measuring serum POCPs in population studies. Persistent organochlorine pollutants (POCPs) are a group of "forever chemicals" that are ubiquitous in the environment and pose adverse health effects to humans. However, the lack of sensitive and widely applicable analytical method for internal POCPs exposure assessment puts limits on the researches of health risk evaluations. Therefore, we developed a method for the measurement of 43 POCPs in human serum using gas chromatography-tandem mass spectrometry (GC-MS/MS). Serum samples were treated with methanol and acid to precipitate protein and remove lipids, respectively. 13C-labeled analogue was spiked and liquid-liquid extraction (LLE) was performed to extract target analytes by hexane and methyl tert -butyl ether. The extract was purified by solid-phase extraction (SPE) and eluted with dichloromethane. The eluate was concentrated under nitrogen stream and reconstituted with toluene. Samples were analyzed by GC-MS/MS operated in electron impact (EI) and multiple reaction monitoring (MRM) mode. Calibration curves of all target analytes showed favorable linearity within the concentration range of 0.008 to 10 μg/L for different POCPs, with regression coefficients above 0.991. The method detection limits and limits of quantification ranged from 0.005 to 0.10 μg/L and 0.017 to 0.34 μg/L, respectively. The recoveries and precision of all analytes at 3 different spike levels were in the range of 65.3 % to 121.8 % and 1.8 % to 13.9 %, respectively. The matrix effects (ME) ranged from 74.9 % to 125.6 %. The results of measuring quality control samples from the National Institute of Standards and Technology (NIST) were with relative deviations of less than 30 %. With an optimized sample preparation procedure, the proposed method has successfully achieved in improving extraction efficiency and reducing ME. It was applied in the simultaneous determination of POCPs in a small volume of human serum in China National Human Biomonitoring. [ABSTRACT FROM AUTHOR]

The mechanisms underlying heritable phenotypic divergence associated with adaptation in response to environmental stresses may involve both genetic and epigenetic variations. Several prior studies have revealed even higher levels of epigenetic variation than genetic variation. However, few population‐level studies have explored the effects of epigenetic variation on species with high levels of genetic diversity distributed across different habitats. Using AFLP and methylation‐sensitive AFLP markers, we tested the hypothesis that epigenetic variation may contribute to differences in plants occupying different habitats when genetic variation alone cannot fully explain adaptation. As a cosmopolitan invasive species, Phragmites australis (common reed) together with high genetic diversity and remarkable adaptability has been suggested as a model for responses to global change and indicators of environmental fluctuations. We found high levels of genetic and epigenetic diversity and significant genetic/epigenetic structure within each of 12 studied populations sampled from four natural habitats of P. australis. Possible adaptive epigenetic variation was suggested by significant correlations between DNA methylation‐based epigenetic differentiation and adaptive genetic divergence in populations across the habitats. Meanwhile, various AMOVAs indicated that some epigenetic differences may respond to various local habitats. A partial Mantel test was used to tease out the correlations between genetic/epigenetic variation and habitat after controlling for the correlation between genetic and epigenetic variations. We found that epigenetic diversity was affected mostly by soil nutrient availability, suggesting that at least some epigenetic differentiation occurred independently of genetic variation. We also found stronger correlations between epigenetic variation and phenotypic traits than between genetic variation and such traits. Overall, our findings indicate that genetically based differentiation correlates with heterogeneous habitats, while epigenetic variation plays an important role in ecological differentiation in natural populations of P. australis. In addition, our results suggest that when assessing global change responses of plant species, intraspecific variation needs to be considered. [ABSTRACT FROM AUTHOR]

We investigate the correlations between two qubits in the Grover search algorithm with arbitrary initial states by numerical simulation. Using a set of suitable bases, we construct the reduced density matrix and give the numerical expression of correlations relating to the iterations. For different initial states, we obtain the concurrence and quantum discord compared with the success probability in the algorithm. The results show that the initial states affect the correlations and the limit point of the correlations in the searching process. However, the initial states do not influence the whole cyclical trend. [ABSTRACT FROM AUTHOR]

Aiming at the poor transient convergence and real-time performance of the horizontal vibration state variables of the high-speed elevator car system, and the low control accuracy and stability, this paper proposes an adaptive control strategy to ensure the transient response of the elevator car system. First, a prescribed preset transient performance function is introduced into the controller design to control the variation range of the state variables and ensure the steady transient performance of the elevator car; Second, representing the information of observation error/control error through algebraic operations, designing an adaptive law based on e-correction, estimating unknown parameters in the elevator car system, and achieving online parameter updates; Then, using neural networks to learn and compensate for unknown dynamics in the elevator car system, and solving the online estimation problem of neural network weights through adaptive laws, so that the tracking error and weight estimation error converge to a tight set near zero; Finally, using MATLAB/SIMULINK to compare and analyze the four control algorithms of passive control, PID control, adaptive control based on gradient descent method and transient response adaptive control proposed in this paper under two different rail excitations: Random excitation and pulse excitation. The simulation results show that the adaptive control strategy proposed in this paper effectively suppresses the horizontal vibration of the elevator car, makes the state variables have faster convergence speed and smaller convergence error, and ensures the stable and transient performance of the elevator car system. [ABSTRACT FROM AUTHOR]

High precision polycrystalline diamond (PCD) micro cutting tools with complex geometrical features which widely used in the field of aerospace, automotive, electronics, etc. are difficult to fabricate by traditional processes. Ultrashort pulse laser (ULPL) with extremely high peak power and short pulse duration is the ideal tool for processing PCD materials. In this study, an industrial picosecond laser source with the wavelength of 1064 nm and the pulse duration less than 10 ps was used to fabricate PCD micro drills. A graphical user interface (GUI) and a computer-aided manufacturing (CAM) module have been developed. A twist PCD micro drill with a diameter of 0.75 mm was successfully fabricated by picosecond pulsed laser roughing and grinding finishing. The mechanisms of ablation removal and surface integrity generation in picosecond pulsed laser processing of PCD materials were discussed. The results show that PCD micro drills roughed by a picosecond pulsed laser have sharp geometric edges. The thickness of thermal damage layer induced by the picosecond pulsed laser is very small, which could be completely removed in the grinding finishing process. Compared to conventional grinding, the fabricate time of PCD micro drill based on the newly proposed method is reduced by 48.2%. [ABSTRACT FROM AUTHOR]

We use the state-mandated stay-at-home orders during the coronavirus pandemic as a setting to study whether political beliefs inhibit compliance with government orders. Using geolocation data sourced from smartphones, we find residents in Republican counties are less likely to completely stay at home after a state order has been implemented relative to those in Democratic counties. Debit card transaction data shows that Democrats are more likely to switch to remote spending after state orders are implemented. Heterogeneity in factors such as Covid-19 risk exposure, geography, and county characteristics do not completely rule out our findings, suggesting political beliefs are an important determinant in the effectiveness of government mandates. Political alignment with officials giving orders may partially explain these partisan differences. [ABSTRACT FROM AUTHOR]

Anthracite can be used to produce graphite. This paper takes Taixi anthracite as the research sample. The changes of micro-morphology and lattice structure of carbon during graphitization were characterized using scanning electron microscope (SEM) and transmission electron microscope (TEM), to explore the change from stereo organic complex structure to planar ordered structure. The results showed: carbon atoms in different chemical environments in the original anthracite would have different microstructures after the heat treatment at high temperature. We found polycrystalline graphite, monocrystalline graphite, and microsphere intermediates. This means that the graphitization process of anthracite is a complex process with multiple conversion mechanisms. By adjusting the content of coal ash, the products of coal-based graphite with different crystal structure can be obtained. [ABSTRACT FROM AUTHOR]

The magnetic microrobots actuated by an external magnetic field can access distant, enclosed, and small spaces under fuel‐free conditions, which is apromising technology for manipulation and delivery under microenvironment; however, the complicated fabrication method limits their applications. Herein, three techniques including melt electrospinning writing (MEW), micromolding, and skiving process are combined to successfully mass‐produce tadpole‐like magnetic polycaprolactone/Fe3O4 (PCL/Fe3O4) microrobot. Importantly, the tadpole‐like microrobots under an external magnetic field can achieve two locomotions: rolling mode and propulsion mode. The rolling motion can approach the working destination quickly with a speed of ≈2 mm s−1. The propulsion motion (0−340 µm s−1) can handle a microcargo. Such a simple and cost‐effective production method shows a great potential for scale‐up fabrication of advanced shape‐design, mass‐production, and multifunctionality microrobot. [ABSTRACT FROM AUTHOR]

An experimental apparatus was designed to study the non-shock initiation reaction evolution process of a HMX (cyclotetramethylenete-tranitramine)-based pressed PBX (Plastic Bonded Explosive)-A column under the main constraint of the inertial mass of the explosive bulk, with strong bottom and circumferential confinements and with the strength of a PMMA plate cover as the threshold to control the internal reaction pressure. The HMX-based pressed PBX-A column was ignited by black powder. The experimental results show that the reaction violence was quite mild, and the estimated amount of explosive consumed at the time of the PMMA plate cracking was only 1.8% of the thickness. The velocity curve of the constrained surface shows that the internal reaction pressure at the initial stage of the structural deformation shows the "quasi-isobaric" characteristic, and the estimated reaction pressure at this stage was about 157.41 MPa. [ABSTRACT FROM AUTHOR]

In recent years, the exploration of natural compounds possessing both immunostimulatory and antiviral activities has attracted growing attention in aquaculture research. Consequently, the pursuit of identifying natural products exhibiting anti-SVCV potential as immunostimulants holds significant promise, offering a pathway to mitigate the economic ramifications inflicted by SVCV outbreaks in aquaculture settings. Among them, rhein emerges as a particularly compelling contender. Boasting a widespread distribution, well-established extraction methods, and multiple biological activities, it has exhibited the capacity to enhance the antiviral activity of host cells in vitro by blocking the viral internalization process, with a peak inhibition rate of 44.0%. Based on this intervention, rhein inhibited apoptosis and mitochondrial damage triggered by SVCV infection, ultimately producing a significant antiviral effect. Moving beyond the laboratory setting, rhein's efficacy translates effectively into in vivo scenarios. It has demonstrated substantial antiviral potency by increasing the expression of antiviral-related genes, most notably, retinoic acid-inducible gene I (RIG-I), interferon-φ (IFN-φ) and IFN-stimulated gene product 15 (ISG15). In concert with this genetic modulation, rhein efficiently reduces the viral load, precipitating a consequential enhancement in the survival rate of SVCV-infected fish, elevating it to an encouraging 16%. In conclusion, the outcomes of our investigation offer a compelling testament to rhein's potential as a valuable immunomodulator in the battle against SVCV infections in aquaculture, and the remarkable attributes exhibited by rhein underscore its viability for future commercial deployment. • Rhein exhibits anti-SVCV activities both in vitro and in vivo. • Rhein blocks the viral internalization process in vitro. • Rhein reduces mortality and viral load in SVCV-infected zebrafish. • Rhein enhances the expression of antiviral-related genes. [ABSTRACT FROM AUTHOR]

The microstructure of a material determines its macroscopic properties. In this study, coal with varying degrees of metamorphism was selected as raw materials. High-temperature graphitization was carried out under the same heat treatment conditions following different pretreatment. The coal-based graphite with different microstructure (polycrystalline graphite, monocrystalline graphite, spherical graphite, honeycomb graphite, and rod-like graphite) were obtained. The results show that the graphitization effect of high-rank coal is better than that of low-rank coal but the graphitization degree of products can be greatly improved after pretreated by pickling. Their resistivity is the same order of magnitude as that of natural graphite, and they all have porous structures with large specific surface areas. They are not only good semeconductor materials but also have potential applications in other fields based on their interesting microstructrues. [ABSTRACT FROM AUTHOR]

Background: Pregnancy can be stressful for women and families, so the life satisfaction of pregnant women may face significant challenges. This study aimed to identify the relationship among anxiety symptoms, perceived social support and life satisfaction, and to further explore whether perceived social support can play a mediating role.Methods: This cross-sectional study was conducted from June to September in Shenyang City, China in 2019. 290 effective questionnaires were collected. The Satisfaction with Life Scale (SWLS), the Zung's Self-Rating Anxiety Scale (SAS), the Multi-Dimensional Scale of Perceived Social Support (MSPSS) as well as demographic variables were included in each questionnaire. Hierarchical multiple regression was conducted to explore the mediating role of perceived social support in the relationship between anxiety symptoms and life satisfaction. Then the mediation model was examined by the PROCESS macro for SPSS.Results: After adjusting control variables, anxiety symptoms were negatively associated with life satisfaction and explained 14.7% of the variance. Higher level of perceived social support was related to higher level of life satisfaction, explaining 21.0% of the variance. Perceived social support partly mediated the relationship between anxiety symptoms and life satisfaction for pregnant women.Conclusions: Perceived social support played a mediating role between anxiety symptoms and life satisfaction among pregnant women. Strategies and measures to improve perceived social support may be expected to buffer the impact of anxiety symptoms on pregnant women's life satisfaction. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are a class of organic compounds that have attracted global attention for their persistence in the environment, exposure to biological organisms, and their adverse health effects. There is an urgent need to develop analytical methodologies for the characterization of PFAS in various sample matrices. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) represents a chromatography-free MS method that performs laser-based ionization and in situ analysis on samples. In this study, we present PFAS analysis by MALDI-time-of-flight (TOF) MS with trapped ion mobility spectrometry (TIMS), which provides an additional dimension of gas phase separation based on the size-to-charge ratios. MALDI matrix composition and key instrument parameters were optimized to produce different ranges of calibration curves. Parts per billion (ppb) range of calibration curves were achieved for a list of legacy and alternative perfluorosulfonic acids (PFSAs) and perfluorocarboxylic acids (PFCAs), while ion mobility spectrum filtering enabled parts per trillion (ppt) range of calibration curves for PFSAs. We also successfully demonstrated the separation of three perfluorooctanesulfonic acid (PFOS) structural isomers in the gas phase using TIMS. Our results demonstrated the new development of utilizing MALDI-TOF-MS coupled with TIMS for fast, quantitative, and sensitive analysis of PFAS, paving ways to future high-throughput and in situ analysis of PFAS such as MS imaging applications. [ABSTRACT FROM AUTHOR]

Surfaces and interfaces of ferroelectric oxides exhibit enhanced functionality, and therefore serve as a platform for novel nano and quantum technologies. Experimental and theoretical challenges associated with examining the subtle electro‐chemo‐mechanical balance at metal‐oxide surfaces have hindered the understanding and control of their structure and behavior. Here, combined are advanced electron‐microscopy and first‐principles thermodynamics methods to reveal the atomic‐scale chemical and crystallographic structure of the surface of the seminal ferroelectric BaTiO3. It is shown that the surface is composed of a native <2 nm thick TiOx rock‐salt layer in epitaxial registry with the BaTiO3. Using electron‐beam irradiation, artificial TiOx sites with sub‐nanometer resolution are successfully patterned, by inducing Ba escape. Therefore, this work offers electro‐chemo‐mechanical insights into ferroelectric surface behavior in addition to a method for scalable high‐resolution beam‐induced chemical lithography for selectively driving surface phase transitions, and thereby functionalizing metal‐oxide surfaces. [ABSTRACT FROM AUTHOR]

Background: Fatigue influences doctors' physical and mental health seriously, additionally, the topic has received wide attention recently. This study aimed to identify the association among resilience, perceived organizational support (POS) and fatigue, and to further explore whether POS could be a moderator in the association between resilience and fatigue in Chinese doctors.Methods: A cross-sectional study was conducted in Liaoning Province in China in 2018. Out of 1000 randomly selected doctors, 866 completed the Chalder Fatigue Scale, the Connor-Davidson Resilience Scale, Survey of Perceived Organizational Support, and the questions about demographic characteristics and job condition variables. The association among resilience, POS and resilience × POS interaction with physical and mental fatigue were examined by hierarchical multiple regression. Simple slope analysis was conducted to visualize the interaction.Results: The association between resilience and physical fatigue was gradually increased in the low (1 standard deviation [SD] below the mean, β = -0.127, P< 0.05), mean (β = -0.292, P < 0.05) and high (1 SD above the mean, β = -0.457, P < 0.05) groups of POS. Additionally, the association was also different in the low (1 SD below the mean, β = -0.240, P < 0.01), mean (β = -0.357, P < 0.01) and high (1 SD above the mean, β = -0.474, P < 0.01) groups of POS.Limitations: Due to the cross-sectional design, the study cannot draw any conclusion of causal relationships among study variables.Conclusions: POS could moderate the association among resilience, physical and mental fatigue. More interventions related to resilience and POS will be helpful to alleviate fatigue among Chinese doctors. [ABSTRACT FROM AUTHOR]

Background: Many patients with advanced non-small cell lung cancer manifested with metastasis, and molecular heterogeneity may exhibit between primary and metastatic tumors. We sought to investigate the clinical detection strategy of primary and metastatic tumors in Chinese patients with NSCLC. Methods: Here, 77 paired tumors of Chinese patients with lung adenocarcinoma were analyzed, and 1836 mutation in hotspot regions of 22 genes were identified by next-generation sequencing. The expression of ALK in these paired tumors was also detected by immunohistochemistry. Results: The results showed that the concordance rate in multiple pulmonary nodules, primary-LN metastasis pairs and primary-distant metastasis pairs was 67.7%, 94.1% and 86.7%, respectively. In multiple pulmonary nodules, the concordance rate was 100% when the pathologic diagnosis was intrapulmonary metastasis, whereas the concordance rate was 23.1% when the pathologic diagnosis was multiple primary tumors. TP53 and CTNNB1 mutations were detected as the recurrent alterations in LN metastasis. Moreover, the concordance of ALK status was observed in these pairs. Conclusions: Our data suggested that hotspot mutations and ALK status in the primary-metastasis pairs had a high concordance in lung adenocarcinoma. Clinical detection of one lesion may be enough to identify the key alterations except that patients are diagnosed with multiple primary tumors or have disease progression after benefiting from target therapy. [ABSTRACT FROM AUTHOR]

It is still a challenging task to segment ultrasound medical images automatically and accurately because of the poor quality of images. To address these problems, a two-stage automatic segmentation scheme based on local entropy and a proposed active contour model for ultrasound images are put forward in this paper. First, a new region-based active contour model in the level set formulation, driven by global and local intensity information, is established for the segmentation. Furthermore, for automatically segmenting the ultrasound images, a coarse segmentation is performed utilizing local entropy information of the ultrasound images, then the coarse segmentation result is used as the initial value of the explicit segmentation based on the proposed model. Several experiments on real ultrasound images demonstrate that the proposed method outperforms other methods on both visual perception and objective evaluation metrics. [ABSTRACT FROM AUTHOR]

Four real recommender system datasets, the Netflix , SMovieLens , LMovieLens and RYM datasets, are analyzed to gain an insight into their user interest characteristics. A preference of active users to cold objects and a diverse interest of inactive users are revealed, which characteristics are introduced to improve the personalized recommendation algorithms. Based on seven different algorithms, we propose a general improvement formula for them, and finally four new algorithms are obtained. Tested on the four datasets, all the new algorithms are found to outperform the original ones in recommendation accuracy, diversity and novelty, except for the diversity and novelty compared with a heat conduction algorithm. And the recommendation accuracy for the cold objects, referring to the objects with small degrees, is also improved. Moreover, one of the new algorithms shows better performance than two other excellent algorithms in many aspects, i.e., the hybrid algorithm of heat conduction and mass diffusion, and the biased heat conduction algorithm. Our work may shed a new light on personalized recommendation from the perspective of connecting empirical study with algorithm design. • Four real recommender system datasets are analyzed. • A preference of active users to cold objects and a diverse interest of inactive users are revealed. • User interest characteristics are introduced to improve recommendation algorithms. • Four improved algorithms are proposed. • The new algorithms are found to be more effective than their previous ones. [ABSTRACT FROM AUTHOR]