Analysis of liquid-vapor mixed migration mechanism in unsaturated soil based on the effect of temperature on soil microstructure.

Moisture migration in unsaturated soils is a result of the interaction between temperature and soil microstructure. In order to reveal the mechanism of moisture increase of subgrade soils under diurnal cycle conditions, a series of macro and microscopic tests were carried out on the unsaturated silty clay and sand soil, including liquid-vapor mixed migration tests simulating a one-dimensional subgrade, environmental scanning electron microscope (ESEM), and matrix suction test. Then, the soil microstructure in microscopic images was investigated using the particle (pores) and cracks analysis system (PACS). Next, the relationship between the thermal effects of the soil-water characteristic curve (SWCC) and changes in soil microstructure was analyzed. Finally, the change mechanism of liquid-vapor mixed migration based on the change in soil microstructural under thermal effects was analyzed. The results showed under the diurnal cycle, both the silty clay and sand soil columns appeared in the phenomenon of a "diurnal cycle of water vapor migration", which led to moisture accumulation at the top of the soil layer. In silty clay soil column, moisture was primarily driven by water vapor pressure and migrated upwards. Additionally, moisture redistribution led to changes in soil microstructure, which in turn influenced the process of moisture migration. The moisture content in the upper soil layer increased making both inter-aggregate and intra-aggregate pores decrease. The moisture content in the lower soil later decreased, leading to the water-holding capacity of the lower soil layer to increase. So, the moisture migration gradually decreased at night. In the sand soil column, moisture migration was mainly driven by gravity potential and migrated downwards. Moisture redistribution made inter-aggregate pore and matrix suction of the upper soil layer increase, leading to an increase in moisture migration at night.

Assessment of radiation doses and DNA damage in pediatric patients undergoing interventional procedures for vascular anomalies.

Interventional procedures (IPs) have been widely used to treat vascular anomalies (VA) in recent years. However, patients are exposed to low-dose X-ray ionizing radiation (IR) during these fluoroscopy-guided IPs. We collected clinical information and IR doses during IPs and measured biomarkers including γ-H2AX, chromosome aberrations (CA), and micronuclei (MN), which underpin radiation-induced DNA damage, from 74 pediatric patients before and after IPs. For the 74 children, the range of dose-area product (DAP) values was from 1.2 to 1754.6 Gy∙cm2, with a median value of 27.1 Gy∙cm2. DAP values were significantly higher in children with lesions in the head and neck than in the limbs and trunk; the age and weight of children revealed a strong positive correlation with DAP values. The treated patients as a group demonstrated an increase in all three endpoints relative to baseline following IPs. Children with vascular tumors have a higher risk of dicentric chromosome + centric ring (dic+r) and cytokinesis-block micronucleus (CBMN) after IPs than children with vascular malformations. The younger the patient, the greater the risk of CA after IPs. Moreover, rogue cells (RCs) were found in five children (approximately 10%) after IPs, and the rates of dic+r and CBMN were significantly higher than those of other children (Z = -3.576, p < 0.001). These results suggest that there may be some children with VA who are particularly sensitive to IR, but more data and more in-depth experiments will be needed to verify this in the future.

Point radiance calculation of GI-MMF and its application in a fiber connection.

Graded-index multimode fiber (GI-MMF) is advantageous for low modal dispersion over its counterpart step-index multimode fiber, which renders it highly suitable for high-speed data transmission in short-range data links. To date, several theories and calculation methods have been proposed for MMF transmission and connection, most of which are based on geometric optics. Although the basic principle is extremely simple, the manipulation of the modal power distribution (MPD) variation along the transmission line that considerably affects the channel bandwidth still poses several challenges. Currently, the radiance of a point on the emitting fiber is assumed to evaluate the MPD at fiber connections, as its measurement or calculation method has not been determined yet. Thus, this paper proposes a method to numerically estimate the point radiance of GI-MMF using the near-field pattern (NFP) and far-field pattern (FFP) of the fiber. The method used data based on analytic functions representing NFP and FFP and yielded accurate estimations for the point radiance of GI-MMF; the accuracy was verified by comparing the fiber NFP and FFP calculated from the derived point radiance with the NFP and FFP analytical functions. In addition, the numerical aperture of the points on the fiber end-face obtained from the point radiance was in accordance with the theoretical value. Subsequently, we substituted the point radiance function of the GI-MMF into the matrix model that was established to compute the MPD conversion at fiber connectors under generic misalignments, including lateral, longitudinal, and angular offsets. Accordingly, the influence of misalignments on the MPD in GI-MMF connectors was assessed, and the performance of the fiber channel linked by GI-MMF was evaluated.

Experimental study on shear characteristics of the silty clay soil-ice interface.

During the spring thawing, the decrease of soil-ice interface strength by temperature may lead to slope instability. For this reason, some researchers have explored the relationship between temperature and soil-ice interface strength. However, previous studies have not systematically explored the change law of strength at the soil-ice interface from negative temperature to 0 °C. Therefore, direct shear tests were conducted at different shear temperatures and different moisture contents. The effects of temperature and moisture content on strength, cohesion, and internal friction angle are analyzed, while the shear failure mechanism of specimens at different temperatures is discussed according to the location of the shear failure surface. The results show that: Shear properties of soil ice specimens are related to the unfrozen moisture content. The strength of the sample decreases with increasing temperature, and the change in strength is most significant from - 2 to - 0 °C. The strength reduction in this range is from 21.8 to 74.8%, and the higher the moisture content the more obvious this phenomenon is. The shear index tends to decrease with the increase of unfrozen water content, and the greater the increase of unfrozen water, the faster the decrease of both, especially in stage 2. When the temperature is higher than - 5℃, the failure surface is located above the soil-ice interface, and the strength of the specimen is similar to that of the frozen soil. When the temperature is - 10℃, the shear damage surface appears at the soil-ice interface, and the strength of the specimen is determined by the strength of the soil-ice interface.

Anxiety and Depression Among Imaging Doctors in Post-COVID-19 Period.

To investigate the mental state of medical imaging staff in Shandong Province, China, who have been on the forefront of the COVID-19 epidemic during its late stage in China. Questionnaires designed to assess anxiety and depression were administered on-location, and 5331 complete results were collected. SPSS software was used for statistical descriptions and analysis. Rates of anxiety disorders and depression among medical imaging workers in Shandong Province, China, were 6.1% and 6.5%, respectively, higher than those of anxiety and depression in Chinese residents before the epidemic. The outbreak in Xinjiang, China; virus mutation in Japan; and spread of the epidemic due to occupational errors were the primary reported causes of anxiety and depression among image workers. Medical imaging workers showed evidence of psychological abnormalities during the late stage of the epidemic in China.

Influence of Temperature and Sodium Sulfate Content on the Compaction Characteristics of Cement-Stabilized Macadam Base Materials.

This paper describes an experimental investigation into the compaction characteristics of cement-stabilized macadam base materials (CSMBM) in a saline soil area. Through the field tests, the main causes of arch expansion in an existing road were analyzed. Based on this, the compaction tests and microscopic tests were designed to analyze the impacts of temperature, sodium sulfate content and cement content on the compaction characteristics of CSMBM. Then, the orthogonal test was designed to analyze the effects of the degree of the temperature, the cement content, and the sodium sulfate content on the compaction results of the CSMBM. Feld tests results show that the temperature, sodium sulfate content and cement content may be the main causes of arch expansion. The compaction tests show that with the temperature increasing, the optimal water content (OWC) decreases, but the maximum dry density (MDD) increases; with the sodium sulfate content increasing, the OWC increases, but the MDD decreases; with the cement content increasing, both MDD and OWC increase. The microscopic tests show that the increase of temperature and cement content is beneficial to the compactness between cementitious materials and aggregates, while the increase of sodium sulfate content makes the whole structure of cementitious materials and aggregates increasingly rough. The orthogonal test shows that the temperature has the greatest influence on the MMD, and the sodium sulfate content has the greatest influence on the OWC. Thus, in a sulfate saline soil area, the construction temperature, the sodium sulfate content and the cement content should be controlled to ensure the compaction quality of CSMBM.

Assessment of Genomic Instability in Medical Workers Exposed to Chronic Low-Dose X-Rays in Northern China.

The increasing use of ionizing radiation (IR) in medical diagnosis and treatment has caused considerable concern regarding the effects of occupational exposure on human health. Despite this concern, little information is available regarding possible effects and the mechanism behind chronic low-dose irradiation. The present study assessed potential genomic damage in workers occupationally exposed to low-dose X-rays. A variety of analyses were conducted, including assessing the level of DNA damage and chromosomal aberrations (CA) as well as cytokinesis-block micronucleus (CBMN) assay, gene expression profiling, and antioxidant level determination. Here, we report that the level of DNA damage, CA, and CBMN were all significantly increased. Moreover, the gene expression and antioxidant activities were changed in the peripheral blood of men exposed to low-dose X-rays. Collectively, our findings indicated a strong correlation between genomic instability and duration of low-dose IR exposure. Our data also revealed the DNA damage repair and antioxidative mechanisms which could result in the observed genomic instability in health-care workers exposed to chronic low-dose IR.

Bi-soliton generation and its properties in stretched pulse fiber ring laser.

We studied the formation of bi-soliton pairs in Kerr-type stretched pulse fiber ring laser (SPFRL). By solving the modified Ginzburg-Landau (GL) equaition, which models the SPFRL, we show that anti-phase bi-soliton can be generated robustly if a low level Gaussian pulse is injected into the ring laser in the initial set-up stage. With the help of properly selected high order nonlinear gain coefficient, the observation of anti-phase bi-soliton pairs is expected to become feasible in experiments.

Nationwide desert highway assessment: a case study in China.

The natural environment affects the construction of desert highways. Conversely, highway construction affects the natural environment and puts the ecological environment at a disadvantage. To satisfy the variety and hierarchy of desert highway construction and discover the spatio-temporal distribution of the natural environment and its effect on highway construction engineering, an assessment of the natural regional divisions of desert highways in China is carried out for the first time. Based on the general principles and method for the natural region division, the principles, method and index system for desert highway assessment is put forward by combining the desert highway construction features and the azonal differentiation law. The index system combines the dominant indicator and four auxiliary indicators. The dominant indicator is defined by the desert's comprehensive state index and the auxiliary indicators include the sand dune height, the blown sand strength, the vegetation coverage ratio and the annual average temperature difference. First the region is divided according to the dominant indicator. Then the region boundaries are amended according to the four auxiliary indicators. Finally the natural region division map for desert highway assessment is presented. The Chinese desert highways can be divided into three sections: the east medium effect region, the middle medium-severe effect region, and the west slight-medium effect region. The natural region division map effectively paves the way for the route planning, design, construction, maintenance and ongoing management of desert highways, and further helps environmental protection.