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Background It has been more than 2 years since the 2019 novel coronavirus disease (COVID-19) pandemic destabilized the world, adversely affecting not only physical health, but also mental health. During this time, frontline medical workers were at a greater health risk, especially female medical workers. Changes or abnormalities in the menstrual cycle—an important indicator of women’s health—may jeopardize female reproductive functioning. Considering that emotional health and sleep status may be related to the menstrual cycle, this study aimed to investigate the association between menstrual cycle changes, anxiety, sleep dysfunction, and other factors among female medical workers during the COVID-19 pandemic. Methods A cross-sectional survey was conducted by distributing online questionnaires to female medical workers in China from February to May 2022. The study included 160 women aged 18–45 years old. The questionnaires covered data related to the participants’ sociodemographic characteristics, medical and reproductive history, and lifestyle. The Rating Scale for Clinical Manifestations of Menopathy (SCMM), Self-Rating Anxiety Scale (SAS), and Sleep Dysfunction Rating Scale (SDRS) were utilized. Data were analyzed using chi-square tests, t-tests, and linear regression analysis. Results A total of 160 female medical staff were randomly selected in this research, of whom seven scored less than 3 points, 85 scored 3–11 points, and 68 scored more than 11 points on the total score of the SCMM. Compared to pre-pandemic scores, scores of dizziness and tinnitus were significantly higher during the COVID-19 pandemic. Scores corresponding to the following clinical symptoms were also higher during the pandemic: Menopathy, including hypaphrodisia, dim complexion, abnormal urination, languidness, dim menstruation, thin menstruation, dysmenorrhea, and empty or saggy lower abdomen (p Conclusions In this study, we found that menstruation in female medical workers was affected by the COVID-19 pandemic. Furthermore, regular exercise and good physical condition were protective factors, while anxiety and insomnia were risk factors for menstrual abnormalities.

Unidirectional SiCf/SiC minicomposite with a scheelite (CaWO4) interphase coating was fabricated through the precursor infiltration and pyrolysis method. Fractography of the SiCf/SiC minicomposites indicated that weak fiber/matrix bonding can be provided by the CaWO4 interphase. Furthermore, interfacial debonding stress of SiCf/CaWO4/SiC minicomposite was evaluated through the fiber push-out test, and estimated to be 80.7 ± 4.6 MPa. In-situ tensile SEM observation of SiCf/CaWO4/SiC minicomposite after oxidation at 1000–1100 °C was carried out, and thermal compatibility between CaWO4 interphase coating and SiC fiber or matrix after heat treatment at 1300 °C was investigated.

Exposure to urban birth, childhood trauma, and lower Intelligence Quotient (IQ) were the most well-established risk factors for schizophrenia in developed countries. In developing countries, whether urban birth is a risk factor for schizophrenia and how these factors are related to one another remain unclear. This study aimed to investigate whether IQ mediates the relationship between urban birth or childhood trauma and first-episode schizophrenia (FES) in China. Birthplace, childhood trauma questionnaire (CTQ), and IQ were collected from 144 patients with FES and 256 healthy controls (HCs). Hierarchical logistic regression analysis was conducted to investigate the associations between birthplace, childhood trauma, IQ, and FES. Furthermore, mediation analysis was used to explore the mediation of IQ in the relationship between birthplace or childhood trauma and FES. After adjusting for age, sex and educational attainment, the final model identified urban birth (odds ratio (OR) = 3.15, 95% CI = 1.54, 6.44) and childhood trauma (OR = 2.79, 95% CI = 1.92, 4.06) were associated an elevated risk for FES. The 52.94% total effect of birthplace on the risk of FES could be offset by IQ (indirect effect/direct effect). The association between childhood trauma and FES could be partly explained by IQ (22.5%). In total, the mediation model explained 70.5% of the total variance in FES. Our study provides evidence that urban birth and childhood trauma are associated with an increased risk of FES. Furthermore, IQ mediates the relationship between urban birth or childhood trauma and FES.

Dividing a network into communities has great benefits in understanding the characteristics of the network. The label propagation algorithm (LPA) is a fast and convenient community detection algorithm. However, the community initialization of LPA does not take advantage of topological information of networks, and its robustness is poor. In this paper, we propose a stable community detection algorithm based on density peak clustering and label propagation (DS-LPA). First, the local density calculation method in density peak clustering algorithm is improved in finding the community center of the network, so as to build a suitable initial community, which can improve the quality of community partition. Then, the label update order is determined reasonably by computing the information transmission power of nodes, and the solutions for multiple candidate labels are provided, which greatly improved the robustness of the algorithm. DS-LPA is compared with other seven algorithms on the synthetic network and real-world networks. NMI, ARI, and modularity are used to evaluate these algorithms. It can be concluded that DS-LPA has a higher performance than most comparison algorithms on synthetic network with ten different mixed parameters by statistical testing. And DS-LPA can quickly calculate the best community partition on different sizes of real-world networks.

The influence of the initial structure on formation of austenite, evolution of structure, and elevation of operating characteristics of steel SA508 Gr.3 (0.24% C, 1.40% Mn, 0.88% Ni, 0.54% Mo) after an intercritical heat treatment (IHT) is studied. After the IHT, the grain size of the hypoeutectoid ferrite in the steel with an initially ferritic-bainitic structure is much larger than in the initially bainitic or martensitic structures. The density of the low-angle and high-angle boundaries is much higher in the steel with initial bainitic or martensitic microstructure. The initial microstructure affects substantially the strength and the impact toughness of the steel subjected to IHT. The mechanical properties are increased as a result of refinement of the microstructure and growth of the density of grain boundaries.

People start to use heroin in different patterns. This study identified three initial heroin use patterns in a heroin use cohort: No-factor initial pattern (with no factors of initial heroin use), Single-factor initial pattern (with 1 of 3 factors of initial heroin use), and Multiple-factor initial pattern (with 2 or 3 factors of initial heroin use). The cumulative heroin relapse rate was 53.3%, 62.4%, and 72.7% respectively for No-factor, Single-factor, and Multiple-factor initial patterns during the 5-year follow-up. The adjusted hazard ratio (AHR) was 1.401 (95% CI: 1.091–1.799, p = 0.008) in Single-factor initial pattern and 2.381 (95% CI: 1.546–3.668, p

The low yield ratio and continuous yielding behavior of ferrite-martensite dual-phase (DP) steels are determined by their production process and microstructure. In this work, high-resolution in situ electron backscatter diffraction (EBSD) experiments were performed to study the deformation and hardening behavior of DP steel in uniaxial tensile, plane strain and shear stress states. In the EBSD experiments, we first collected the data for different deformation stages from the same area for each sample (loading was paused during EBSD data collection). Subsequently, we analyzed the strain contouring maps, geometrically necessary dislocation (GND) distribution and ferrite deformation of all the samples based on the postprocessing of the EBSD data. The results showed that (i) the volume expansion accompanying the austenite-to-martensitic transformation during annealing gives rise to ferrite plastic deformation, and the residual deformation after overaging of the fine ferrite grains near the martensite group is the largest; (ii) the high-density GND bands of the shear sample is the same as the shear stress/strain direction, and the high-density GND bands of the uniaxial tensile and plane strain samples are perpendicular to their maximum stress/strain directions; and (iii) in the shear state, the average strain of ferrite grains in each grain size range is similar; but the deformation tends to aggregate toward large-size grains in the uniaxial tensile and plane strain samples.

This study investigates the microstructure morphology in a single-track wall of Ti-47Al-2Cr-2Nb alloy produced by direct laser deposition. The as-deposited wall mainly exhibited an alternative-band microstructure containing a dendrite band and α2/γ lamellar band, which is considered to result from the influence of the heat affected zone. A tailoring method was proposed and alternative-band microstructures with various equiaxed colony fractions, and even nearly fully equiaxed colony microstructures, were successfully obtained.

Bainite transformation in steels is influenced by various factors. In the present work, bainite transformation in medium carbon high alloyed steel was investigated focusing on the influence of preexisting VC carbides on the morphology and transformation kinetics of the subsequently formed bainite. Hot-work die steels were held at 950 °C for various times to precipitate VC carbides, then rapidly cooled from 950 to 350 °C and held at this temperature for the bainite transformation. It is found that the bainite transformation was obviously accelerated by the preexisting VC carbides precipitated at the austenite region. The precipitation of carbides leads to a decrease in carbon concentration in the matrix, which decreases the effective activation energy and increases the highest temperature for the nucleation of bainite. Besides, bainite was observed to grow beside the VC carbides. It suggests that the VC carbides in the matrix act as nucleation sites for the bainite transformation. In the specimens, the bainite transformation is accelerated, and a higher fraction of bainite is formed when there are carbides in the matrix.

Dilatometry is a useful technique to obtain experimental data concerning transformation. In this paper, a dilation conversional model was established to calculate carbides fraction in AISI H13 hot-work tool steel based on the measured length changes. After carbides precipitation, the alloy contents in the matrix changed. In the usual models, the content of carbon atoms after precipitation is considered as the only element that affects the lattice constant and the content of the alloy elements such as Cr, Mo, Mn, V are often ignored. In the model introduced in this paper, the alloying elements (Cr, Mo, Mn, V) changes caused by carbides precipitation are incorporated. The carbides were identified using scanning electron microscope and transmission electron microscope. The relationship between lattice constant of carbides and temperature are measured by high-temperature X-ray diffraction. The results indicate that the carbides observed in all specimens cooled at different rates are V-rich MC and Cr-rich M23C6, and most of them are V-rich MC, only very few are Cr-rich M23C6. The model including the effects of substitutional alloying elements shows a good improvement on carbides fraction predictions. In addition, lower cooling rate advances the carbides precipitation for AISI H13 specimens. The results between experiments and mathematical model agree well.

Atom probe tomography was utilized to investigate Cu precipitation in a high-strength low-alloy steel isothermally aged at 500 °C for 1, 4, 16, and 64 h after water-quenching from 900 °C. With prolonged aging time, the Cu-rich precipitates (CRPs) increased in size and decreased in number density, and gradually evolved from spheroidal to elliptical in morphology. The small CRPs were rich in a high amount of Fe and a certain amount of Ni and Mn at their early nucleation stage. The large CRPs with increased size due to extensive aging contained less Fe and more Cu at their later growth stage. Additionally, Ni and Mn were both readily to segregate at the CRP/matrix heterophase interfaces, and Mn was higher in content than Ni in the precipitate interior especially when the CRPs were large in size.

Macrosegregation refers to the chemical segregation, which occurs quite commonly in the large forgings such as nuclear reactor pressure vessel. This work assesses the effect of macrosegregation and homogenization treatment on the mechanical properties of a pressure-vessel steel (SA508 Gr.3). It was found that the primary reason for the inhomogeneity of the microstructure was the segregation of Mn, Mo, and Ni. Martensite, and coarse upper bainite with M-A (martensite-austenite) islands have been obtained, respectively, in the positive and negative segregation zone during a simulated quenching process. During tempering, the carbon-rich M-A islands decomposed into a mixture of ferrite and numerous carbides which deteriorated the toughness of the material. The segregation has been substantially minimized by a homogenizing treatment. The results indicate that the material homogenized has a higher impact toughness than the material with segregation, due to the reduction in M-A island in the negative segregation zone. It can be concluded that the microstructure and mechanical properties have been improved remarkably by means of homogenization treatment.

We address the competitive precipitation and coprecipitation of three types of secondary phases, i.e., Cu-rich precipitates (CRPs), reverted austenite (RA), and alloyed carbide, in a high-strength low-alloy steel with austenite reversion treatment at 675 °C by using electron back-scatter diffraction, transmission electron microscopy, and atom probe tomography. There is a strong competitive diffusion of Ni and Cu participating in austenite reversion and Cu precipitation with the fact that no CRPs are detected in and around the RA. Meanwhile, there is also a strong competitive diffusion of austenite stabilizing element Ni and carbide-forming elements Cr and Mo into the pre-existing C-rich zone, leading to the formation of nonequilibrium alloyed carbide deviating from the stoichiometric composition. On the other hand, the alloyed carbide and CRPs provide constituent elements for each other and make the coprecipitation thermodynamically favorable. The knowledge on the interactive formation of these three features provides versatile access to tailor the distributional morphology of CRPs, RA, and alloyed carbide via a multistage heat treatment and thus realize their beneficial effect on strength and toughness.

The influence of Cu-rich precipitates (CRPs) and reverted austenite (RA) on the strength and impact toughness of a Cu-containing 3.5 wt pct Ni high-strength low-alloy (HSLA) steel after various heat treatments involving quenching (Q), lamellarization (L), and tempering (T) is studied using electron back-scatter diffraction, transmission electron microscopy, and atom probe tomography. The QT sample exhibits high strength but low impact toughness, whereas the QL samples mostly possess improved impact toughness but moderate strength, but the QLT samples again have degraded impact toughness due to additional tempering. The dispersion of nanoscale CRPs, which are formed during tempering, is responsible for the enhanced strength but simultaneously leads to the degraded impact toughness. The RA formed during lamellarization contributes to the improved impact toughness. Based on the present study, new heat treatment schedules are proposed to balance strength and impact toughness by optimizing the precipitation of CRPs and RA.

Effects of nitrogen and carbon content on precipitation behavior in two 9–12% Cr ferritic heat-resistant steels during isothermal transformation were investigated. Isothermal aging treatments at 700 °C after solution annealing were carried out for the different periods up to over 220 h. Microstructure characterization was performed by many characterization methods, such as physicochemical phase analysis, X-ray diffraction and scanning electron microscope etc. It was found that Cr-rich M2N nitride was formed as the main precipitate in the alloy A with content of 0.15% N and 0.03% C in wt%, together with some Cr-rich M23C6 carbide and Nb-rich MN nitride. Comparatively, the aged alloy B with 0.05% N and 0.11% C, predominantly contains Cr-rich M23C6 carbides. Besides, both alloys showed the similar microstructure evolution process: The precipitates were found to be formed initially along prior austenite grain boundaries, then grew toward interior of grain in the form of cell with the increasing aging time. Meanwhile, the cell growth feature was also discussed based on the experimental observation in well-controlled specimens.

A multistep heat treatment process consisting of intercritical tempering between quenching and conventional tempering contributed to the development of a ferrite–martensite dual-phase structure in a Ni- and Cu-containing high-strength low-alloy steel. By using electron backscatter diffraction and scanning transmission electron microscopy, the microstructures were found to have an elongated lathlike morphology with carbide and Cu precipitates located especially at the boundaries of ferrite and martensite crystals. Atom probe tomography reveals at atomic scale the existence of solute-diluted ferrite and solute-rich martensite, and the later phase was considered to be transformed from the reverse austenite that was formed during intercritical tempering. Cu precipitation greatly correlates with the microconstituents, resulting in different distributional characteristics of Cu precipitates within these two phases and at their boundaries. It is a promising process to utilize Cu precipitation strengthening and phase transformation toughening simultaneously in alloy steels.

Wrinkling and buckling of nano-films on the compliant substrate are always induced due to thermal deformation mismatch. This paper proposes effective means to control the surface wrinkling of thin film on the compliant substrate, which exploits the curvatures of the curve cracks designed on the stiff film. The procedures of the method are summarized as: 1) curve patterns are fabricated on the surface of PDMS (Polydimethylsiloxane) substrate and then the aluminum film with the thickness of several hundred nano-meters is deposited on the substrate; 2) the curve patterns are transferred onto the aluminum film and lead to cracking of the film along the curves. The cracking redistributes the stress in the compressed film on the substrate; 3) on the concave side of the curve, the wrinkling of the film surface is suppressed to be identified as shielding effect and on the convex side the wrinkling of the film surface is induced to be identified as inductive effect. The shielding and inductive effects make the dis-ordered wrinkling and buckling controllable. This phenomenon provides a potential application in the fabrication of flexible electronic devices.

Several studies have reported an association between enteric bacteria and atherosclerosis. Bacterial 16S ribosomal RNA (rRNA) gene belong to Enterobacteriaceae have been detected in atherosclerotic plaques. How intestinal bacteria go into blood is not known. Zonulin reversibly modulate intestinal permeability (IP), the circulating zonulin levels were increased in diabetes, obesity, all of which are risk factors for atherosclerosis. It is unclear whether the circulating zonulin levels were changed in coronary artery disease (CAD) patients and modulate IP. The 16S rRNA gene of bacteria in blood sample was checked by 454 pyrosequencing. The zonulin levels were determined by enzyme-linked immunosorbent assay (ELISA) methods. The distribution of zonulin was detected by confocal immunofluorescence microscopy. Bacteria and Caco-2 cell surface micro-structure were checked by transmission electron microscopy. A high diversity of bacterial 16S rRNA gene can be detected in samples from CAD patients, most of them (99.4%) belong to Enterobacteriaceaes, eg. Rahnella. The plasma zonulin levels were significantly higher in CAD patients. Pseudomonas fluorescens exposure significantly increased zonulin expression and decreased IP in a time dependent manner. The elevated zonulin increase IP and may facilitate enteric translocation by disassembling the tight junctions, which might explain the observed high diversity of bacterial 16S rRNA genes in blood samples.