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Performance appraisal is an important means to assess employees' work performance. It serves to enhance the production competence of frontline employees through feedback in order to promote green and low-carbon development of coal enterprises. The current performance appraisal system of coal enterprises is still limited as it is mostly result-oriented, overlooking assessment on environmental protection, individual skills and learning capabilities. In this light, this study adopts the key performance indicators(KPI)method and analytic hierarchy process(AHP)in optimizing the present indicators in the performance appraisal system to highlight the "dual carbon" objective. Specifically, this study proposes environmental indicators as part of the new performance appraisal system, and suggests detailed measures to ensure its implementation.

Cancer of unknown primary (CUP) is a heterogeneous tumor type that has been diagnosed as a metastatic tumor by pathological examination, but the primary tumor cannot be identified through comprehensive clinical examination. The incidence of CUP accounts for approximately 1%–2% of all tumors. CUP progresses rapidly and has a short course. The treatment and prognosis of patients with CUP are closely linked to the primary site. In clinical settings, identifying the primary tumor remains challenging. Scholars have focused on improving the detection rate. Novel technologies, such as gene expression profiling, high-throughput sequencing, epigenetics, and liquid biopsy, have been successively applied to identify the primary tumor of CUP accurately, sensitively and specifically. With the guidance of molecular diagnosis, targeted therapy, immunotherapy, and combination therapy will usher in the era of precision treatment for CUP, which may become a typical example for individualized therapy.

BackgroundDibutyl phthalate (DBP) is a common plasticizer in daily life and has been proved to be related to the exacerbation of allergic asthma. Domestic and foreign studies have shown that lipid peroxidation is closely related to the severity of asthma, which can be used as a basis for the diagnosis and treatment of asthma. Whether DBP can induce lipid peroxidation in allergic asthma remains to be further studied.ObjectiveTo investigate whether DBP aggravates allergic asthma by inducing lipid peroxidation in allergic asthma mice.MethodsEighty male BALB/c mice were randomly divided into 4 groups, namely control group, DBP group (40 mg·kg−1), 50 μg ovalbumin (OVA) group (allergic asthma model group), and DBP+OVA group. The DBP group and the DBP+OVA group were given DBP by gavage from Day 1 to 28, and the OVA group and the DBP+OVA group were sensitized by intraperitoneal injection of OVA, once every 3 d, a total of 5 injections, from Day 9 to 21. From Day 29 to 35, the OVA group and the DBP+OVA group were challenged by OVA atomization. After the exposure, samples of blood and lung were collected. The airway hyperresponsiveness of mice was observed by lung function analysis. The serum contents of immunoglobulin E (IgE), OVA-specific immunoglobulin E (OVA-IgE), and lung homogenate levels of interleukin 4 (IL-4) were detected by enzyme-linked immunosorbent assay (ELISA) to evaluate airway allergic inflammation. The pathological changes of lung tissues were observed after hematoxylin-eosin (HE) staining and collagen fiber (Masson) staining. The contents of reactive oxygen species (ROS), lipid ROS, glutathione peroxidase 4 (GPX4), reduced glutathione (GSH), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) in lung homogenates were detected by ELISA to evaluate lipid peroxidation.ResultsThe results of lung function analysis showed that compared with the control group, the inspiratory resistance (Ri) and expiratory resistance (Re) of the OVA group and the DBP+OVA group were increased, and the lung compliance (Cldyn) was decreased. The DBP + OVA group was more severe, and the difference between the OVA group and the DBP + OVA group was statistically significant (P

Traditional orchard production is facing problems of labor shortage due to the aging, difficulties in the management of agricultural equipment and production materials, and low production efficiency which can be expected to be solved by building a smart orchard that integrates technologies of Internet of Things(IoT), big data, equipment intelligence, et al. In this study, based on the objectives of full mechanization and intelligent management, a smart orchard was built in Pinggu district, an important peaches and pears fruit producing area of Beijing. The orchard covers an aera of more than 30 hm2 in Xiying village, Yukou town. In the orchard, more than 10 kinds of information acquisition sensors for pests, diseases, water, fertilizers and medicines are applied, 28 kinds of agricultural machineries with intelligent technical support are equipped. The key technologies used include: intelligent information acquisition system, integrated water and fertilizer management system and intelligent pest management system. The intelligent operation equipment system includes: unmanned lawn mower, intelligent anti-freeze machine, trenching and fertilizer machine, automatic driving crawler, intelligent profiling variable sprayer, six-rotor branch-to-target drone, multi-functional picking platform and finishing and pruning machine, etc. At the same time, an intelligent management platform has been built in the smart orchard. The comparison results showed that, smart orchard production can reduce labor costs by more than 50%, save pesticide dosage by 30% ~ 40%, fertilizer dosage by 25% ~ 35%, irrigation water consumption by 60% ~ 70%, and comprehensive economic benefits increased by 32.5%. The popularization and application of smart orchards will further promote China's fruit production level and facilitate the development of smart agriculture in China.

Tibetan Plateau (TP) has high impact on weather, climate, and water cycle of China, and it also affects the flood and drought in south China by modulating the onset and retreat of the Asian monsoon. However, owning to the lack of direct observations, the knowledge of microphysical characteristics and mechanisms inside the clouds over TP is still seriously lacking. During the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX-Ⅲ), field observations is carried out in the summer of 2014, which employed ground-based and airborne instruments. By using the aircraft measurements collected during the TIPEX-Ⅲ, the microphysical characteristics and precipitation formation mechanisms of summertime clouds are studied. The results show that clouds detected by the aircraft are mainly newly born or developing mixed-phase convective clouds, as well as some residual clouds. The maximum and average concentrations of cloud drops are 1.1×105 L-1 and (9±10)×103 L-1, respectively, and the order of magnitude is 104 L-1, which is lower than clouds of plain and maritime regions by 1-2 orders. The maximum concentration for larger cloud particles is 28.82 L-1, and the order of magnitude is 100-101 L-1, which is also lower than other regions. The maximum liquid and total water content are 0.25 g·m-3 and 1.33 g·m-3, respectively, and the order of magnitude is 10-1-100 g·m-3, with abundant supercooled liquid water content in the clouds. The uplifting velocity distributes mainly in the range of 1-4 m·s-1 with a maximum of 4.3 m·s-1, indicating the convective clouds over the TP are weaker than other regions. The cloud drop size distributions (DSD) are mostly bimodal with different second peaks at the larger end, and some of the DSDs are unimodal, which are mainly found in newly borne clouds. There are more large cloud drops and drizzles in the clouds over the TP, which is the result of active warm rain processes. And the ice particles mainly consist of opaque and dense graupels as well as some needles and plates, indicating active rimming processes. The warm rain processes do not generate rain directly, but contribute to the subsequent glaciation and rimming processes, leading to the quick formation of precipitation over the TP. The residual clouds show similar ice characteristics with convective clouds, but much drier and weaker, and they also maintain small amount of supercooled liquid water.

Pesticide application using UAV sprayer has become a new highlight in the development of agricultural machinery and plant protection in China. Spray droplets from UAV could reach the crop canopy and deposit on the control target surface under the assistance of rotor's downwash airflow after atomization, including a secondary atomization effect of airflow on the droplets, so the spray performance of aerial pesticide application is inseparable from the effect of the rotor's downwash airflow field. In order to explore the effect of downwash airflow field on UAV's spray deposition characteristics, taking the main model of eight-rotor UAV with "X-type" as the research object and designing the actual measuring test, a multi-channel micro-meteorology measurement system(MMMS) was used to determine the downwash airflow speed at different horizontal positions, and meanwhile the tracer Allura Red solution was applied instead of chemicals to obtain the distribution characteristics of spray deposition. The visual analysis of the measured results of the downwash airflow field distribution was focused, and then the distribution characteristics of both the downwash airflow field and the droplet deposition at a certain flight height and speed, and the correlation relationship between them were analyzed. During the flight operation of the 8-rotor UAV, as the flight speed increased from 1.0 to 6.0 m/s and the flight height increased from 1 to 2 m, the intensity of the downwash airflow field in directions of X, Y, and Z generally changed from strong to weak, and the distribution state changed from concentration to dispersion; the X direction airflow was the vortex generated by the interaction between the downwash airflow and the outside air and its effect on droplets was reversed flight direction; the airflow in Y direction was to the both sides from flight path, caused by the combination of downwash airflow and ground effect; the airflow in Z direction, the vertical downward component of the downwash airflow, had a direct promotion effect on spray deposition. Significant negative correlations were shown between both the flying speed and the peak value in the range of the downwash airflow field (P 0), that was, the stronger the downwash airflow field in the vertical ground direction, the more droplets deposited in the effective spray swath. When the flight speed increased to 6.0 m/s, the wind speed was significantly reduced, and the promotion effect of the downwash airflow field on the droplet deposition disappeared(P> 0.05). The operation speed of UAV should not be set faster than 6.0 m/s to avoid the chemicals loss caused by the weakened effect of the downwash airflow field. The findings of this study are expected to provide theoretical basis and data support for improving the quality of low-altitude and low-volume application operations and the formulation of UAV field operations specifications.

How to extract characteristic parameters from vibration signals with noise is a key problem of bearing fault diagnosis. A novel method based on Morlet wavelet-Singular Value Decomposition（ SVD） and Variable Predictive Model based Class Discriminate（ VPMCD） was proposed in this paper aiming to solve this problem. Firstly,Morlet wavelet transform was used to pre-process the signals in the time domain to obtain a time-frequency coefficient matrix,then SVD was applied to the matrix to remove noise and extract the weak fault information in the corresponding dimensions according to the singular value curvature spectrum; Secondly,the signal components near the optimal meature were selected,and the Shannon energy entropy were used as the characteristic parameters to construct the feature vectors,which were then used to establish the fault identification model based on VPMCD. Finally,5-fold cross validation method and Jackknife test method were adopted to verify the proposed method,and the results have demonstrated its effectiveness.

Traditional annular laminar flow analysis method applied in drilling engineering has poor accuracy and does not apply to complicated rheological models. A general method of calculating annular laminar pressure drop of drilling fluids with different rheological models was proposed, compared with traditional method, and verified using experiment data in published articles. Based on annular slot flow model, the pipe flow equation was popularized in annular and an annular flow equation was established, and the relationship between annular flow and shear stress at pipe wall was established by combining annular flow equation and fluid's rheological equation. If annular flow is given, shear stress at pipe wall can be got, and then the annular pressure drop is also available. Compared with traditional methods, the general method is adapt to any rheological model of annular laminar flow, and has good universality, simple modeling process and high accuracy. The calculation results based on experiment data in published articles show: no matter the flow rate is high or low, the results of the general method match the measured results well, which makes up the error of traditional method. Key words: annular laminar pressure drop, annular flow equation, non-newtonian fluid, rheological equation, traditional method, general method, drilling fluids

The use of ethephon can achieve early and concentrated the machine-harvested cotton boll opening. The purpose of this study is to analyze the effect of the boll-period shortening on the boll weight, fiber quality, and relationship, when the ethephon was sprayed at different stages of the boll development with a selection of 18 materials. The results showed that when the period of cotton was 47--69 days, spraying ethephon at the age of boll was 40.5--49.7 days, which could advance boll opening by 3.5--5.7 days. It took 64.1--69.7 days for fiber to fully mature under ethephon, while it took 54.8--60.5 days for cotton seed. When boll was opened 1.5--6.2 days earlier, the probability of boll weight and fiber quality decreasing was up to 58.0%--76.5%. To achieve an early opening of the boll, ethephon can be applied at the boll age of 34.8--44.1 days, when the boll weight (< 0.26 g) and fiber quality damage (length reduction < 0.28 mm and fiber strength < 0.30 cN tex--1) at the top of cotton plant are reduced by 5% and 1%, respectively. In addition, the boll period was shortened in some materials, but the boll weight, fiber length, and strength were increased, with the 9.5%--23.5% probability. Therefore, the reasonable use of ethephon in some cotton varieties can shorten the boll period and improve the boll weight and quality. [ABSTRACT FROM AUTHOR]

Localized tooth breakage is one of the common failures of spur gears, which affects the smooth and safe operation of spur gear transmission systems. The tooth collision cannot be neglected, and it is especially important to reveal the meshing-impacting dynamic characteristics of the gear system under localized tooth breakage to improve the safe and stable operation of the gear system. Based on the gear meshing principle and the dissipative collision contact force model, the drive-side tooth meshing model and back-side tooth impacting model are established with considering the transient nature of tooth back-side contact. The tooth surface meshing model and tooth back collision model under partial breakage are established. According to the contact state and force environment of the gear pair, the multi-state meshing-impacting behaviour under local breakage is classified, and the discrete meshing-impact dynamics model of an involute spur gear system under local breakage is established to explore the influence of local breakage on the meshing stiffness and load distribution. The mechanism of contact force under partial tooth breakage is revealed, and the influence of load coefficient and meshing frequency on the nonlinear dynamics is studied by defining two Poincaré maps. It is found that local tooth breakage affects the contact force of single-and double-tooth meshes and reduces gear load carrying capacity. Larger loads inhibit back-side impact, and smaller loads induce the coexistence behaviour and back-side impact. Larger or smaller meshing frequency induce back-side impact behaviour. The coexistence of chaotic and periodic motions induces back-side impact behaviour, and localized tooth breakage affects the coexistence phenomenon and aggravates the complexity of the dynamic behaviour. The dynamic model of gear system considering energy dissipation and nonlinear vibration under the presence of local tooth breakage of the pinion is explored, and the conditions of back-side impact are studied. This research provides new methods and ideas for nonlinear dynamic modelling and analysis of faulty gear systems.

In order to optimize the preparation method of antibacterial polypropylene materials and improve the performance of antibacterial polypropylene, so that it has potential application in daily life. The preparation conditions of typical antibacterial polypropylene materials were summarized from melt blending, impregnation and coating methods. The research progress on the performance improvement of antibacterial polypropylene was introduced from the aspects of grafting chemical modification, block chemical modification and crosslinking chemical modification. The application of antibacterial polypropylene in household appliance industry, packaging industry and medical biomaterials in recent years was summarized. The research show that different preparation methods and chemical modification have different effects on the properties of antibacterial polypropylene. [ABSTRACT FROM AUTHOR]

Objective To explore whether occlusion site affects success rate, methods of recanalization, perioperative complications, and prognosis of the recanalization in chronic internal carotid artery occlusion (CICAO). Methods Thirty - nine patients diagnosed as CICAO from January 2017 to January 2020, and treated by endovascular recanalization were retrospectively reviewed. Baseline information, endovascular procedures, complications, clinical and angiographic prognosis were collected. Effects of occlusion site were analyzed. Results Thirty patients (76.92% ) achieved successful endovascular recanalization. Successful recanalization rates varied among groups with different occlusion sites of extracranial short segment (CI, CI-C2 or CI-C3), medium segment (CI-C4), long segment (CI-C5 or CI-C6) and intracranial short segment (C6 or C6-C7), were 9/11, 8/10, 9/14 and 4/4, respectively. Sole angioplasty with balloon was applied in 7 patients (23.33%), sole stenting in 15 (50%), angioplasty with balloon and stents in 8 (26.67%). Among different occlusion sites of extracranial short, medium, long segment, and intracranial short segment, sole angioplasty with balloon was applied in 0/9, 1/8, 3/9 and 3/4, respectively; while sole stenting was applied in 9/9, 4/8, 1/9 and 1/4, showing a gradually increasing trend. Procedure-related complications were not related with occlusion site. One patient (33.33%) died, while 29 surviving patients during a median clinical follow-up of 16 (4, 27) months with successful recanalization, but one (3.45%) developed ipsilateral minor stroke due to restenosis. With a median angiographic follow-up of 5.50 (3.50, 8.00) months, 2 restenosis and 3 reoclusion were found in 21 patients, all of which came from medium and long segment occlusion. Conclusions Endovascular recanalization is feasible and effective in CICAO with relatively low procedure - related complications. However, success rate of recanalization decreases in groups of long segment occlusion. Application of angioplasty methods differs in groups with varying occlusion sites. Procedure - related complications seems relatively low. While, restenosis and re-occlusion are mostly found in long segment occlusion site. [ABSTRACT FROM AUTHOR]

The dynamic change of the solid filling hydraulic support's spatial pose state is difficult to directly identify under complex geological conditions. The existing pose measurement system has some missing pose parameters. In order to solve the above problems, a full pose measurement system of the solid filling hydraulic support is designed. The 3D model of the solid filling hydraulic support is established by using 3D Max modeling software. Based on different characteristic nodes of the solid filling hydraulic support, nine parameters reflecting the full spatial pose are obtained by using the multi-sensor fusion measurement method. The nine parameters include the inclination angle of the support base (included angle with the horizontal plane), the attitude angle of the top beam (included angle with the horizontal plane), the support height, the pushing distance, the status of the guard plate, the inclination angle of the pushing and compacting mechanism (included angle with the rear top beam), the pushing distance of the pushing and compacting mechanism, the distance between the guard plates of the support group, and the included angle between scraper conveyor central groove and support pushing gear. The inclination angle sensors are arranged at the front top beam, the rear top beam, the base, and the jack of pushing and compacting mechanism. They are used for measuring the inclination angle of the base of the support, the attitude angles of the front top beam and the rear top beam. The displacement sensors are arranged on the pushing gear and pushing and compacting mechanism of the support. The sensors are used for measuring the pushing distance. The vision sensors are used for collecting image data. The monocular vision measurement model is established. The converting of a global coordinate system into a local coordinate system is obtained. Therefore, the distance between the guard plates of the solid filling hydraulic support set, the angle between the support pushing gear and the center groove of the scrap conveyor, the state of the guard plates and the support height can be analyzed and calculated. The existing virtual simulation system of solid filling hydraulic support lacks in-depth research in data analysis, motion relationship constraints and other aspects. In order to solve these problems, a virtual simulation system of solid filling hydraulic support based on Unity3D is designed. The system realizes the motion simulation of the support by using Unity3D. The system reflects the change of the pose state of the running support in real time. The virtual simulation system of solid filling hydraulic support based on Unity3D is used together with the full pose measurement system of solid filling hydraulic support, which can truly reflect the running state of solid filling hydraulic support, and ensure the stability and the reliability of data of solid filling hydraulic support simulation. The systems can provide technical support for the smooth running of solid filling hydraulic support.

We selected the grid of 5 m × 5 m in a dynamic monitoring plot (340 m × 300 m) as the sampling unites and chose 5 structural characteristics (density, average crown breadth, coverage, conspicuousness and average height) to study the spatial heterogeneity of community structure of Picea crassifolia forest in Dayekou Basin of Qilian Mountains by the fractal geometry and geostatistics methods. The results showed that the order of spatial variation in these characteristics was: density > average crown breadth > conspicuousness > coverage > average height, with the variation coefficient ranging from 43.7% to 79.6%. Moran's I index indicated that the structural variables had different degrees of spatial autocorrelation, and the order of autocorrelation was density > average height> coverage > average crown breadth > conspicuousness, with the range of –0.047–0.382. The exponential semivariation model well fitted the spatial variability in different structural features, and the range was 24.6–68.1 m. The variables displayed moderate spatial autocorrelation except for coverage, while the other variables had strong spatial autocorrelation, and the fractal dimension of the variables was close to 2, indicating a low spatial dependence among variables. The variables presented a superposing characteristic of zonal and patchy structures except for density and coverage, while the other variables presented strong patchiness property. Density and coverage had a certain spatial dependence on average crown breadth, conspicuousness and average height. Density and coverage for the spatial heterogeneity of community structural of P. crassifolia forests were 10 m and 0.5 hm2, respectively. [ABSTRACT FROM AUTHOR]

At present, wired networks, wireless networks, satellite networks and high - speed networks all can carry the data payload, and the main features of heterogeneous networks are high BER (Bit Error Rate), long delay, asymmetry of bandwidth in some links, and so on. Since TCP is designed for normal wired networks so as not to work very well in heterogeneous networks. OPNET is used to simulate heterogeneous networks, and obtain the regular of how the BER, delay and asymmetry affect the TCP performance. The obtained regular can provide a reference for experiments on optimization of TCP performance in challenged networks. [ABSTRACT FROM AUTHOR]

Background Carotid endarterectomy (CEA) is currently the preferred treatment for severe carotid kinking and stenosis. Kinking is generally believed to be a relative contraindication for endovascular stent placement. This article aims to study the necessity, feasibility and security of carotid angioplasty and stenting (CAS) for symptomatic carotid kinking combined with stenosis, and summarize clinical experience of this disease according to therapeutic results. Methods Twenty - two cases with symptomatic carotid kinking and high-grade stenosis demonstrated by digital subtraction angiography (DSA) were performed CAS. Their clinical manifestations, imaging features, procedure safety and follow-up data were collected and retrospectively analyzed. All patients understood CEA and voluntarily received CAS. Results Twenty - two cases with carotid kinking and stenosis were all successfully performed CAS (the success rate was 100%) without stent-related disability or mortality. Twenty-four self-expandable stents were implanted. The mean degree of stenosis was reduced from 85.63% before stenting to 11.25% after stenting and the angles of kinking were improved from < 90° to > 120° (Metz' category). During the period of hospitalization, no transient ischemic attack (TIA) or cerebral infarction occurred, and the clinical symptoms and signs of ischemia, such as dizziness and headache, were improved or disappeared. Besides, no permenant complications or deaths happened. All cases were followed up from 6 to 72 months, among whom 1 patient experienced contralateral carotid TIA, and 2 patients experienced ipsilateral carotid TIA (one indicated aspirin resistance in platelet aggregation test and the other showed restenosis in DSA). Computed tomography angiography (CTA) of 10 patients and Duplex scan of 7 patients during the follow-up demonstrated carotid in good morphology and fluent blood flow, without kinking or restenosis. Conclusion CAS is a feasible and safe therapeutic method and maybe helpful to lower the risk of cerebral ischemia for the patients with symptomatic kinking and stenosis. However, further study is still needed. [ABSTRACT FROM AUTHOR]

PURPOSE: To evaluate the role 18F-FDG PET in the identification of head and neck neoplasm in contrast to CT/MRI. METHODS: Fifty four patients with head and neck primary tumors underwent PET and CT/MRI with two weeks before surgery. Hispathology analysis was used as the gold standard for diagnosis. Difference of sensitivity, specificity and accuracy between PET and CT/MRI was analyzed using SPSS13.0 software package for Chi-square test. RESULTS: PET correctly identified the primary tumors in 48/54 patients and CT/MRI identified the primary tumors 43/54 patients. The sensitivity, specificity and accuracy of PET for the identification of primary tumors were 7.4%, 15.3% and 9.3%, higher than those of CT/MRI, but not significantly. CONCLUSIONS: The sensitivity, specificity and accuracy of PET for identification of head and neck primary tumors is higher than those of CT/MRI, but the difference was not statistically significant. [ABSTRACT FROM AUTHOR]

In this study, the effects of the addition of different amounts of salt (0%, 1%, 2% and 3%) at five stages of processing: raw shrimp, blanching, marination, soaking for 2 h and soaking at 4 ℃ for 24 h, on the quality and volatile flavor compounds of marinated crayfish were investigated. The results showed that L* values increased and then decreased as the processing stages proceeded, while a* and b* values both continued to increase. But salt addition had little effect on the color difference. Additionally, moisture content decreased and then increased, and was affected little by salt addition. For 1%, 2% and 3% salt addition, hardness, elasticity, chewiness and adhesion showed an initial increasing and subsequent decreasing trend. Without salt addition, hardness and chewiness continued to increase. For each group, elasticity and cohesiveness increased and then did not show any significant change. The electronic nose results could be roughly divided into four parts, raw shrimp and blanching, marination, soaking for 2 h, and soaking at 4 ℃ for 24 h. There were also some differences between the less and more salt addition groups. The electronic tongue results showed that as salt addition increased or the processing stages proceeded, saltiness, astringency, and umami taste increased, and other taste attributes changed little. Gas chromatography-ion mobility spectrometry (GC-IMS) analysis showed that salt addition and marination had a positive effect on the volatile flavor of crayfish. However, excessive salt addition and too long processing time were detrimental to volatile flavors. In conclusion, the addition of salt and processing stages can affect the quality and flavor of marinated crayfish.

Offering the advantages of easy preparation and low cost, polymer systems account for many of the high-performance materials used in industry. With the widespread application of polymer materials, higher requirements for the properties of polymer products have been proposed. Recently, polymer-based functional composites have been a worldwide research focus, and the structure of the composites directly affects their properties. The special multilayer structure of shells and trees often brings excellent performance or special functions. Discussing the strength and toughness mechanism of natural materials helps guide new functional composite preparation. In recent decades, a novel micro/nano-lamination technology has attracted the interest of academia and industry. Micro/nano-lamination technology is a layer-by-layer assembly (LbL) technology, which can combine two or more types of polymers into tens of thousands of layers alternately arranged, and each microlayer thickness can reach nanometer level to form composite materials with an alternating layered structure. Compared with solution LbL assembly methods, such as dip coating, spin coating, and spray coating, it is a continuous melt processing technique that involves no solvent, which has the advantages of flexibility, versatility, economy, and eco-friendliness. Compared with the composites prepared by blending melt extrusion or with fewer layers, the shape memory properties, electrical properties, barrier properties, and mechanical properties of composites prepared by micro/nano-lamination technology are considerably improved. As an application of biomimetic materials in the polymer research field, multilayer alternating composites prepared using micro/nano-lamination have a special multilayer structure, rich layer interface, and micro/nano-scale layer confined space. The multilayer composites prepared by micro/nano-lamination have an important positive synergistic effect on mechanical properties, and the unique multilayer structure can adjust stress distribution, stress transfer, and microcrack propagation. In this paper, according to the research status of micro/nano-lamination, the principle and process of micro/nano-lamination are briefly introduced. The mechanical property enhancement mechanism of multilayer alternating composites is reviewed, including interlayer interface interaction, layer interface-induced crystallization, regulation of polymer phase morphology, regulation of the dispersion orientation of inorganic particles, and in situ fiber formation. Micro/nano-lamination technology can coordinate the properties of different materials, integrate the excellent properties of many types of polymer materials, and make composite materials with good comprehensive properties. This model of high-performance functional materials has a broad market application prospect.

Porous media are widely found in underground rocks, biomimetic, and engineering materials. However, the current flow theory of fluids (liquid and gas, etc.) is incomplete to study flows in small and complex pores, thus a new theory is urgently needed for studying a large number of fluid flows in porous media. The theory of meso-scale flow in porous media is a “mysterious key” to unlock the flow of nano-micron porous media. At present, a large number of fluid flow problems need an immediate solution in porous media such as shale oil and gas development, soil seepage, human capillary network, and carbon nanotube (CNT). With the advancement of world petroleum engineering technology, unconventional oil and gas reservoirs have become the main areas of development in the petroleum industry. There are a large number of nano-scale pores in unconventional oil and gas reservoirs, and the existing macro-statistical methods of Darcy and non-Darcy percolation cannot reveal the nonlinear flow mechanism and effective production mechanism of fluid in mesopores. Thus, it is urgent to carry out theoretical research on meso-flow in porous media to provide a theoretical basis for unconventional oil and gas development. This paper summarizes the research results in this area, including those of the authors. The current research status of fine and meso flow in porous media is summarized from three aspects: (1) theoretical analysis, (2) experimental research, and (3) numerical model, focusing on key issues such as the relationship and characterization of meso-scale fluid flow interface and micro-mechanical properties, meso–macro network simulation, meso-scale fluid (oil/water, gas/water) flow, meso-dynamic mechanism, and mathematical models. On this basis, the importance of the research on the interface effect and meso-mechanical characteristics of fine and micro-scale fluid flow, the nonlinear flow mechanism of the fine and meso-scale fluids, the construction of a mathematical model reflecting the meso-scale flow under the action of micro-forces, and the formation of a network simulation method are introduced. The study provides certain guiding significance for unconventional oil and gas development processes, revealing the meso-causes affecting flow, clarifying the production mechanism under different conditions, and promoting further development of the discipline of seepage mechanics.

With the development of material design theories and synthesis technologies, clay-based composite materials have been controllably prepared and successfully applied in many fields, such as biomedicine, the automotive industry, petrochemical engineering, and wastewater treatment. To date, for the preparation of clay-based composite materials, the physical and chemical properties of clay must be fully considered, including the chemical composition, crystal structure, particle size, morphology, and surface charge. Halloysite, which has a tubular crystal structure, is a curly layered aluminosilicate clay with abundant reserves and a low price for constructing composite materials. The inner and outer surfaces of halloysite nanotubes are composed of Al−OH octahedrons and Si−O tetrahedrons, respectively, which ionize in opposite ways in water, resulting in opposite charges on the inner and outer surfaces. Therefore, the selective modification of halloysite can be achieved by chemical or electrostatic adsorption of the required chemical reagent. Additionally, the modified halloysite nanotubes can be used in catalysis and the loading and release of drug molecules. Moreover, because of its nanotube structure, the halloysite can be used to construct rough structures in micro- or nano-scale. By incorporation with low-surface-energy materials, the hydrophobic halloysite-based composite materials can be prepared for self-cleaning and oil-water separation. In this review, we introduced the rational design and preparation strategies of the hydrophobic halloysite-based composite materials. Then, we summarized the applications of these prepared composite materials in oil-water separation, hydrophobic self-cleaning coating, and the loading and sustained release of drug molecules. In addition, the related mechanisms and strategies for performance improvement were systematically discussed. Finally, the existing challenges and promising future directions in this research field were proposed. The halloysite-based composite materials have enhanced properties that are highly required, including enhanced mechanical and adhesive strength, excellent scratch and wear resistance, self-healing, and higher compatibility with living organisms. We believe fruitful promising results can be achieved in this field with more effort.

The existing design methods of strip coal pillar are conservative. Therefore a more rational and effective design method of strip coal pillar is needed to improve the coal recovery rate. Based on the unified strength theory (UST),a formula of limit strength for strip coal pillar was derived, which can take intermediate principal stress into account rationally. Then, analytical solutions of yielding width and remained width for strip coal pillar were presented and compared with the extended results of Wilson formula and generalized SMP criterion. Finally, parametric studies were discussed. The results show that the unified formula of limit strength, yielding width and remained width for strip coal pillar obtained in this paper is a series of results and has very broad theoretical values; the effects of intermediate principal stress and strength parameters (cohesion and inner friction angle) of coal seam on the strip coal pillar design are significant and should be fully considered; the result of Wilson formula is too conservative and the result of generalized SMP criterion is a linear approximation of the unified formula. [ABSTRACT FROM AUTHOR]

Roller wear is an important cause of pilverizer failure.Roller wear is affected by many factors.In this paper, combined with the research on the abrasion of grinding roller, the wear mechanism of the soft roller caused by the soft particles of wheat was reviewed.The paper points out the influencing factors of the grinding roller wear from the characteristics of abrasive and grinding roller as well as the working conditions,and expounds the antifriction technology, which provides a reference for the study of the grinding and wear reduction technology of the grinding machine.

Currently the majority of water quality assessment in China is based on comparison parameters of water with those of drinking water standards.However, to what extent the pollutants influence human health is less known.Herein, Shuangcun karst water samples in central-southern Shandong province were chosen to evaluate human health risk.Using the risk assessment model of USEPA, the risk induced by two carcinogenic substances, such as As, Cr(Ⅵ) and seven non-carcinogenic substances(Hg, F, CN-, NO2--N, NH4+-N, NO3--N, phenols) are evaluated.Results show that concentration of NO3--N and NO2--N in samples from several sites exceeds the limiting value of Hygienic Standard for Drinking Water(GB5749-2006).In terms of annual personal health risk caused by gene toxic substances through water drinking, Cr(Ⅵ) shows greater risk than As.In terms of risk caused by non-gene toxic substances, the induced risk has the sequence of NO3--N> F> NO2--N> Hg> CN-> NH4+-N> phenols.Moreover, the hazard of carcinogenic substances is much stronger than that of non-carcinogenic substances.Cr(Ⅵ) is the primary pollutant.For all the sampling sites, total risk values range from 5.0×10-5 to 10.0×10-5 a-1, and the risk level is Ⅳ(fair).It means that underground water in the sampling area is harmful to human health to some extent.Therefore, it is worth more attention when the studied water serves as the drinking water source.

Taking Handan, Xingtai, Hengshui, and Cangzhou, four cities in southwest Hebei Province along the Beijing-Tianjin-Hebei typical transport route, as examples, we analyzed the variation characteristics of 3a meteorological conditions and PM 2.5 concentration in winter from 2019 to 2021 and used potential source contribution analysis (PSCF) and concentration weight analysis (CWT) to identify the transport characteristics of PM 2.5 in the four cities during the study period. Based on the meteorological air quality model (WRF-CMAQ) transmission matrix method and transport flux method, the contribution of PM 2.5 transport between Handan, Xingtai, Hengshui, and Cangzhou and the surrounding areas was quantitatively assessed; the vertical distribution characteristics of PM 2.5 net transport flux were revealed; and the two main transport routes of PM 2.5 pollution were further identified. The results showed that during the study period, the PM 2.5 concentration decreased by 45.85%, 49.45%, 42.40%, and 31.65%, respectively. The potential source contribution of Handan and Xingtai was mainly distributed in south-central Shanxi (Linfen, Changzhi, and Jinzhong), northern Henan (Xinxiang, Kaifeng, and Zhengzhou), and a small part of Inner Mongolia (PSCF &gt; 0.9). The potential contribution areas of Hengshui and Cangzhou were mainly concentrated in southern Hebei (Handan and Shijiazhuang), central Shanxi (Taiyuan and Yangquan), and some Shandong regions (PSCF &gt; 0.7), and the CWT results were similar to those of PSCF. During the study period, the local contribution (51.11%-62.99%) was slightly higher than the regional contribution (37.01%-48.89%) during winter in the four cities. Affected by horizontal turbulence and vertical diffusion, the impact of regional transmission in 2020 was slightly higher than that in other years (0.50%-9.52%). In 2021, the influence of regional transmission was slightly lower than that of other years (-2.15%--9.52%) due to low PM 2.5 concentration and meteorological factors. For Handan, Xingtai, Hengshui, and Cangzhou, the total inflow (outflow) flux intensity of the four cities during winter and the surrounding areas was in 2020 &gt; 2021 &gt; 2019. For the total net flux, the total inflow (outflow) flux intensity of the four cities in winter was 0.094, -0.070, and 0.087 kt·d -1 (Xingtai:0.212, 0.395, and 0.544 kt·d -1 ; Hengshui:-0.040, -0.228, and 0.185 kt·d -1 ; Cangzhou:0.062, 0.126, and 0.128 kt·d -1 ). During the study, Handan, Xingtai, and Cangzhou were mostly used as transport receptors, whereas Hengshui was mostly used as a transport source. In the range of 0-1 260 m, the net transport flux intensity of PM 2.5 increased basically with the increase in height, and the maximum net flux of the various cities in different periods was different. The maximum net flux of Handan, Xingtai, and Hengshui was 252-1 261 m, 817 m, and 252-817 m, respectively. The maximum net flux in Cangzhou was 252-359 m. By analyzing the transmission characteristics of the four cities, it was found that there were two main transport directions of PM 2.5 , that is, the northwest-southeast direction (Shanxi → Handan → Henan and Shandong; Shijiazhuang → Xingtai → Handan and Shandong; Baoding → Cangzhou → Shandong) and the southwest-northeast direction (Shanxi → Xingtai → Hengshui → Cangzhou → Bohai Bay).

Based on multi-source observation data, such as lidar ceilometer, aircraft AMDAR, and conventional sites, combined with numerical simulation (CAMx-PSAT), this study took the typical cities of the Beijing-Tianjin-Hebei region-Beijing (BJ) urban area and suburbs (Miyun) and Shijiazhuang (SJZ) urban area and suburbs (Pingshan) as the case study areas. The differences in boundary layer height between urban areas and suburbs (ΔPBLH), surface PM 2.5 mass concentration (ΔSurf&#95;PM 2.5 ), vertical PM 2.5 mass concentration (ΔVert&#95;PM 2.5 ), and transmission flux intensity and height distribution characteristics were analyzed. The results showed:due to factors such as anthropogenic heat sources, short-wave radiation, and thermal turbulence, the annual average planetary boundary layer height in urban areas was 8%-29% higher than that in the suburbs, and in different seasons, the monthly average planetary boundary layer height in urban areas was 2% (April in SJZ)-47% (July in BJ) higher than that in the suburbs. Due to the combined effects of anthropogenic emissions, inversions, and atmospheric turbulence, the annual average ρ (PM 2.5 ) in urban areas between 0-1260 m was higher than that in suburbs by 0.1 (SJZ)-29.7 (BJ) μg·m -3 and decreased with the increase in height. The annual average total net flux intensity in urban areas was much greater than that in suburbs, with outflows in urban areas and inflows in suburbs; due to the urban low pressure and the suburban high pressure, suburban thermal circulation was formed. The annual average total net flux intensity in BJ (44.77 t·d -1 ) was greater than that in SJZ (34.44 t·d -1 ). Affected by wind speed and PM 2.5 mass concentration, between 0-1260 m, the fluxes in urban areas and suburbs and surrounding areas showed an obvious trend of increasing net flux intensity with the increase in height above the ground. Furthermore, the transmission exchange between urban areas and suburbs and surrounding areas in January and April had the most obvious impact on the environment. The intensity of the maximum net flux in the lower urban areas and the suburbs in different seasons was significantly different, and the difference between the two was 2.23-4.48 times; however, the height characteristic difference in the intensity of the maximum net flux was small, mainly located at 611-1260 m.

The main function of quartz sand in drinking water treatment has been to remove turbidity, while the microbial effect of its solid-liquid interface has been ignored. In order to solve the limitations of control of the disinfection by-products (DBPs) and opportunistic pathogens (OPs) in common quartz sand, the common quartz sand was modified to iron sand. The maximum DBPs formation potential of typical nitrogenous disinfection by-products (N-DBPs) and carbonaceous disinfection by-products was determined using gas chromatography-ECD. Compared with those of sand, the inhibition effects of halonitromethanes, haloacetamides, and haloacetonitriles by the Fe-sand were increased by 51.51%, 43.66%, and 90.6%, respectively. In addition, the gene copy numbers of Hartmanella vermiformis, Legionella spp., Mycobacterium spp., M. avium , and Naegleria spp. were detected via quantitative qPCR, and the results indicated that the Fe-sand did have a similar significant inhibitory effect on OPs. The Fe-sand had limited ability to enhance the removal of NOM. However, the Fe-sand effectively inhibited the continuous contribution of biofilm to N-DBPs and opportunistic pathogens. The distribution of biofilms on the surface of the Fe-sand filter media was uniform, not likely to fall off, and more stable; however, the suspended biofilms in the effluent were more difficult to aggregate. In addition, the α -helix of the secondary structure in the extracellular protein disappeared in the effluent of the Fe-sand. Therefore, the whole suspended biofilm was easily penetrated by chlorine. The Fe-sand solid-liquid interface did significantly change the microbial community structure and suspended biofilm characteristics, which provides a new concept to ensure the safety of drinking water quality and plays a good theoretical supporting role in the improvement and transformation of the existing process in drinking water treatment plants.

Transposable elements (TEs) are DNA elements that can change their position within or between chromosomes. Most active TEs are retrotransposons, which transpose through a RNA intermediate. Since retrotransposons comprise high proportions in cell genomes, their frequent transposition may cause deleterious effects on the structure and function of the host cell genomes, thus causing serious genetic diseases such as cancer. Host cells therefore developed defense strategies to restrict these mobile elements. piRNA, which belongs to non-coding interfering RNAs, can efficiently decrease the level of retrotransposon RNA intermediates at transcriptional or post-transcriptional stages. In this review, we summarize the progress in mechanisms of piRNA-mediated retrotransposon inhibition. We hope that this review may shed light on the research of transposon and genome regulation.

The aim of this study was to develop cost-saving and efficiency-improving technologies in whole plastic mulching and double ridge-furrow maize in semi-arid region of Loess Plateau. The objective was to investigate soil water balance in farming system with one film used two years. A field experiment was conducted to investigate the effects of different mulching and tillage patterns under one film used two years conditions on the yield, economic benefits, and water use efficiency of maize. There are four treatments: Ridge-furrow planting with complete plastic film mulching, F 1 M; flat-planting with complete plastic film mulching, F 2 M; flat-planting with half plastic film mulching, F 3 M; and flat-planting without mulching, F 4 M, the control. The results showed that the F 1 M and F 2 M treatments had significant effects on the improvement of the production and efficiency compared with the control. The F 1 M and F 2 M treatments improved biomass by 32.8% and 32.9%, enhanced grain yield by 60.0% and 51.7%. Water use efficiency and rainfall use efficiency in F 1 M and F 2 M treatments were increased by 59.8%, 35.9% and 87.6%, 64.4%, respectively. Furthermore, gross output value and input-output ratio of F 1 M and F 2 M treatments under every new plastic film mulched pattern were enhanced by 51.0%, 41.2% and 15.1%, 16.2%, respectively. The production pattern on cost-saving and efficiency-increasing of the system on double ridge-furrow and flat planting with one film used two years, this pattern increased gross output value by 40.8%, 42.2%, and increased input-output ratio by 40.3%, 42.2%, respectively. Under the condition of low precipitation (606.5 mm), total water consumption of ridge-furrow and flat planting under the system of one film used within two years was 731.3 mm and 746.8 mm, the soil moisture deficit was 124.8 mm and 140.3 mm, with enhancement of 22.7% and 38.0%, respectively. The total water consumption of ridge-furrow and flat planting treatments was reduced by 28.6% and 30.0%, and the fallow efficiency was improved by 178.9% and 148.3%. In conclusion, whole plastic mulching with double ridge-furrow and flat planting farming system had positive effects on yield and water use efficiency in semi-arid region of Loess Plateau. Combined with the technology of one film used within two years, this cropping system could be cost saving and efficiency increasing. However, the water deficit under low water condition should be seriously considered in practice.

Blood constituent examination is an important means of health diagnosis. For blood constituent examination, we usually adopt the method of drawing blood, which bring pain and the risk of cross infection to the patient. Near infrared spectrum spectroscopy (NIRS) is a research hotspot in noninvasive blood constituent examination. The spectral data acquisition system of existing instruments is using a Single Chip Microcomputer (SCM) as its microcontroller. The spectral data acquisition system cannot realize the high speed multi-channel acquisition and storage of large amounts of data because of the SCM itself has certain deficiency. So a high speed multi-channel spectral data acquisition system based on Field Programmable Gate Array (FPGA) was designed in this paper in order to realize the system of high speed, multi-channel and high signal-to-noise ratio (SNR) in the area of noninvasive blood constituent examination by near infrared spectroscopy. An Altera Cyclone IV series FPGA was used as the microcontroller in this spectral data acquisition system, which simultaneously controlled two pieces of eight channels AD conversion chip acquiring 16 channels blood pulse wave signal parallel. Under the control of FPGA, the data was cached in FPGA internal ping-pong RAM first, after that it was transferred to an SRAM chip, finally it was sent to the computer via the USB port. Experiment result shows that the spectral data acquisition system can collect 16 channels signal parallel and fast under the sampling frequency of 19 531 Hz and the repetitive signal-to-noise ratio is over 40 000∶1. The system can collect 305 spectrograms per second, more over it can get high SNR human body blood pulse wave signal under the same circumstances. The spectral data acquisition system satisfies the basic requirements of the noninvasive blood constituent examination instrument by NIRS and it can make the instrument collect the human body blood pulse wave data at a high speed. The main innovation point of this article is applying FPGA to the spectral data acquisition system of near infrared noninvasive blood constituent examination instrument. FPGA is able to simultaneously control two pieces of eight channels AD conversion chip acquiring 16 channels blood pulse wave signal parallel. By using FPGA as the microcontroller of the spectral data acquisition system, we solve the problem that SCM as the microcontroller can’t realize multi-channel high speed data acquisition and storage of large amounts of data. The acquisition speed is greatly faster than the system before. The second innovation point of this article is we use FPGA internal resources establish a ping-pong RAM buffer. The spectral data from the AD chip is 24 bit, however, the SRAM chip has only 16 bit data bus. Via the ping-pang RAM buffer, the spectral data can transfer from AD chip to SRAM chip. The ping-pong RAM can realize different digits data seamless transfer from AD chip to SRAM chip.

Objective: To explore the feasibility, safety and efficacy of endovascular reconstructive treatment by multiple overlapping stents with or without coils., Methods: Totally 17 patients of vertebrobasilar fusiform aneurysms treated by multiple overlapping stents with or without coils between September 2011 and September 2015 in Department of Neurosurgery, Beijing Hospital were retrospectively reviewed. There were 15 male and 2 female patients with mean age of (47±13) years. Clinical manifestations included subarachnoid hemorrhage in 5 patients, cerebral ischemia or infarction in the posterior circulation in 5 patients, mass effect accompanied with brainstem infarction in 1 patients, headache or dizziness in 4, and incidental findings in 2 patients. Aneurysm located in intracranial vertebral artery in 11 patients, vertebrobasilar junction in 2 patients, and basilar trunk in 4 patients. Mean aneurysmal size was 18.5 mm×8.0 mm(length×width)., Results: Sole stenting with overlapping stents was performed in 8 patients, and overlapping stents with coils was applied in 9 patients. Post-procedural hemorrhage occurred in a patient with a giant basilar trunk fusiform aneurysm and led to death. The 16 surviving patients were clinically followed up for a mean of 21.1 months. One patient had a modified Rankin score of 4, and the other patients had a good recovery. Among 15 patients with a mean angiographic follow-up of 8.6 months, 9 patients had their aneurysms further thrombosed, 3 patients were stable, and 3 patients with a recurred aneurysm. Final complete occlusion was achieved in 7 patients., Conclusion: Reconstructive treatment by overlapping stents with or without coils is feasible and relative safe in vertebrobasilar fusiform aneurysms.

In order to understand the pollution characteristics of heavy metals in surface water sediments of Yongkang, we analyzed the concentrations of 10 heavy metals including Ti, Cr, Mn, Co, Ni, Cu, Zn, As, Pb and Fe in 122 sediment samples, explored the underlying source of heavy metals and then assessed the potential ecological risks of those metals by methods of the index of geo-accumulation and the potential ecological risk. The study results showed that: 10 heavy metal contents followed the order: Fe > Ti > Mn > Zn > Cr > Cu > Ph > Ni > As > Co, all heavy metals except for Ti were 1. 17 to 3.78 times higher than those of Zhejiang Jinhua- Quzhou basin natural soils background values; The concentrations of all heavy metals had a significantly correlation between each other, indicating that those heavy metals had similar sources of pollution, and it mainly came from industrial and vehicle pollutions; The pollution extent of heavy metals in sediments by geo-accumulation index (Igeo) followed the order: Cr > Zn > Ni > Cu > Fe > As > Pb >Mn > Ti, thereinto, Cr, Zn, Cu and Ni were moderately polluted or heavily polluted at some sampling sites; The potential ecological risk of 9 heavy metals in sediments were in the following order: Cu > As > Ni > Cr > Pb > Co > Zn > Mn > Ti, Cu and As contributed the most to the total potential ecological risk, accounting for 22.84% and 21. 62% , others had a total of 55.54% , through the ecological risk assessment, 89. 34% of the potential ecological risk indexes ( RI) were low and 10. 66% were higher. The contamination level of heavy metals in Yongkang was slight in total, but was heavy in local areas.

We selected the grid of 5 m x 5 m in a dynamic monitoring plot (340 m x 300 m) as the sampling unites and chose 5 structural characteristics (density, average crown breadth, coverage, conspicuousness and average height) to study the spatial heterogeneity of community structure of Picea crassifolia forest in Dayekou Basin of Qilian Mountains by the fractal geometry and geostatistics methods. The results showed that the order of spatial variation in these characteristics was: density > average crown breadth > conspicuousness > coverage > average height, with the variation coefficient ranging from 43.7% to 79.6%. Moran's I index indicated that the structural variables had different degrees of spatial autocorrelation, and the order of autocorrelation was density > average height> coverage > average crown breadth > conspicuousness, with the range of -0.047-0.382. The exponential semivariation model well fitted the spatial variability in different structural features, and the range was 24.6-68.1 m. The variables displayed moderate spatial autocorrelation except for coverage, while the other variables had strong spatial autocorrelation, and the fractal dimension of the variables was close to 2, indicating a low spatial dependence among variables. The variables presented a superposing characteristic of zonal and patchy structures except for density and coverage, while the other variables presented strong patchiness property. Density and coverage had a certain spatial dependence on average crown breadth, conspicuousness and average height. Density and coverage for the spatial heterogeneity of community structural of P. crassifolia forests were 10 m and 0.5 hm2, respectively.

Objective: To evaluate the short-term outcome of single stenting technique for unruptured, wide-necked, tiny aneurysms of the anterior circulation., Methods: Eleven unruptured, wide-necked, tiny aneurysms of the anterior circulation were treated by a single stent deployed in the parent artery between January 2008 and July 2013 in Department of Neurosurgery in Beijing Hospital. The maximum diameter of the aneurysms ranged from 2.0 to 3.0 mm, mean (2.4 ± 0.4) mm, and the dome-to-neck ratios were all ≤ 1.2. The locations were clinoid segment of internal carotid artery (n=2), posterior communicating artery origin (n=4), anterior choroidal artery origin (n=2) and middle cerebral artery bifurcation (n=3). All internal carotid aneurysms were located in the medial and/or ventral wall of the internal carotid artery. The rate of aneurysm obliteration and rupture during follow-up was obtained by repeat angiography and clinic or telephone interview respectively., Results: Sole stent placement in the parent artery was intentionally performed for nine aneurysms, while attempt of coiling after stent deployment for the other two aneurysms failed due to unsuccessful microcatherization. Ten stents were successfully deployed, of which one was used to treat two tandem lesions simultaneously. Only one aneurysm became smaller immediately postprocedure. No perioperative complications occurred. Angiographic follow-up after a mean period of (13 ± 6) months (range 8-24 months) revealed that 8 aneurysms did no change in size, 2 became smaller and only one was totally occluded. Asymptomatic in-stent stenosis of the parent artery was found in all 3 shrinking or occluded aneurysms. No aneurysm rupture was observed in the clinical follow-up., Conclusion: For those unruptured, wide-necked, tiny aneurysms arising at branching sites in the anterior circulation, single stenting technique seems to be a safe alternative treatment, while the short-term rate of aneurysm occlusion is low.

The present paper studies the best detector-distance to improve the near-infrared spectrum signal intensity of the dermis layer and eliminate the interference of the epidermis and subcutaneous layer. First, we analyzed the organizational structure of the skin and calculated the tissue optical parameters of different layers. And we established the Monte Carlo model with the example of glucose absorption peak at 2 270 nm. Then, we used the Monte Carlo method to simulate the light transmission rules in the skin, obtaining the average path length, the average visit depth and the fractions of absorbed energy at each layer with the change in critical angle and detector-distance. The results show that when the photons are incident at an angle less than 45 degrees, you can ignore the effect of the incident angle on photon transmission path, and when the detector-distance is 1 mm, the fraction of absorbed photon energy by the dermis layer is the largest, while it can ensure more energy received by detector. We determined that the best detector-distance is 1mm, which successfully avoids the interference of the epidermis spectral information and obtains large amounts of blood in the dermis layer, which is conducive to the near-infrared non-invasive measurement of biochemical components and the subsequent experiments.

Near-infrared spectroscopy (NIRS) is a reliable, rapid, and non-destructive analytical method widely applied in as a number of fields such as agriculture, food, chemical and oil industry. In order to suit different applications, near-infrared spectrometers are now varied. Portable near-infrared spectrometers are needed for rapid on-site identification and analysis. Instruments of this kind are rugged, compact and easy to be transported. In this paper, the current states of portable near-infrared spectrometers are reviewed. Portable near-infrared spectrometers are built of different monochromator systems: filter, grating, Fourier-transform methods, acousto-optic tunable filter (AOTF) and a large number of new methods based on micro-electro-mechanical systems (MEMS). The first part focuses on working principles of different monochromator systems. Advantages and disadvantages of different systems are also briefly mentioned. Descriptions of each method are given in turn. Typical spectrometers of each kind are introduced, and some parameters of these instruments are listed. In the next part we discuss sampling adapters, display, power supply and some other parts, which are designed to make the spectrometer more portable and easier to use. In the end, the current states of portable near-infrared spectrometers are summarized. Future trends of development of portable near-infrared spectrometers in China and abroad are discussed.

Objective: To explore the imaging findings of non-contrast CT scan, enhancement and HRCT of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma., Methods: All the patients with pathologically proven pulmonary MALT lymphoma underwent non-contrast CT scan, of which 7 underwent CT enhancement and 9 had HRCT. CT features of 16 patients were retrospectively reviewed., Results: Major CT signs of 16 cases were consolidations, nodules and masses, of which 11 had two or more signs and 5 had only one. Together with them, normal or dilated air bronchograms were seen in 13 cases, ground-glass opacity (GGO) in 10, interstitial changes and cysts in respective 5, partial atelectasis and mediastinal and hilar lymphoadenopathy in respective 4, pleural effusion in 2 and MALT lymphoma of tracheobronchial tree in 1. Multiple lesions were found in 12 cases and solitary lesion in 4 cases. Consolidations, greater tubercles and masses mostly had a peribronchovascular distribution. Micronodules occurred in a perilymphatic distribution, of which 8 accompanied other signs.On CT enhancement scans, greater tubercles in the trachea had mild enhancement; most of the consolidations and masses had obvious enhancement, while greater tubercles mostly mild enhancement. CT angiogram sign was found in 3 cases., Conclusion: Most cases with pulmonary MALT lymphoma have consolidations, greater tubercles and masses with normal or dilated air bronchograms which have a peribronchovascular distribution, together with GGO and micronodules in a perilymphatic distribution; the distinctive manifestations are obvious enhancement with CT angiogram sign. Minority cases have interstitial changes, cysts, partial atelectasis, mediastinal and hilar lymphoadenopathy, pleural effusion and MALT lymphoma of tracheobronchial tree.

High signal-to-noise ratio (SNR) of system is necessary to obtain accurate blood components in near infrared noninvasive biochemical analysis. In order to improve SNR of analytical system, high-efficiency double compound parabolic concentrator (DCPC) system was researched, which was aimed at increasing light utilization efficiency. Firstly, with the request of collection efficiency in near infrared noninvasive biochemical analysis, the characteristic of emergent rays through compound parabolic concentrator (CPC) was analyzed. Then the maximum focusing angle range of the first stage CPC was determined. Secondly, the light utilization efficiency of truncated type was compared with standard DCPC, thus the best structure parameters of DCPC system were optimized. Lastly, combined with optical parameters of skin tissue, calculations were operated when incident wavelength is 1 000 nm. The light utilization efficiency of DCPC system, CPC-focusing mirror system, and non-optical collecting system was calculated. The results show that the light utilization efficiency of the three optical systems is 1.46%, 0.84% and 0.26% respectively. So DCPC system enhances collecting ability for human diffuse reflection light, and helps improve SNR of noninvasive biochemical analysis system and overall analysis accuracy effectively.

To increase the signal-to-noise ratio (SNR) of human near infrared (NIR) spectra, so as to improve the stability and precision of calibration model, the empirical mode decomposition (EMD) method was applied. Eighty-one fingertip absorption curves were collected, with the corresponding clinical examination results obtained immediately. By means of outliers detection and removal, finally 78 samples were determined as the research objects. A three-layer back-propagation artificial neutron network (BP-ANN) model was established and worked for prediction. The results turned out that, through EMD method, the prediction correlation coefficient increased greatly from 0.74 to 0.87. RMSEP was reduced from 12.85 to 8.08 g x L(-1). Other indexes were also obviously improved. The overall results sufficiently demonstrate that it is feasible to use EMD method forhigh SNR pulse wave signals, thus improving the performance of noninvasive hemoglobin calibration models. The application of EMD method can help promote the development of noninvasive hemoglobin monitoring technology.

In noninvasive biochemical detection, the differential spectrum method based on the change in blood volume can eliminate the interference of human tissue background in theory, and obtain effective spectrum information of blood. In order to demonstrate the effectiveness of the differential spectrum method, simulated experiment was designed. Biological molecules solutions were used for simulating serum sample, filters with different absorption characteristic were used for simulating interference of tissue background, and an adjustable path-length cell was used for simulating blood volume change. Model accuracies of pre- and post-treatment with differential spectrum method were compared. Thus treated, the root mean square error of cross validation (RMSECV) reduced from 437 to 301 mg x dL(-1). The experimental results indicate that using the differential spectrum method can effectively restrain the interference of tissue background, and greatly improve the prediction precision of calibration model.

The spectral subtraction approach with different flow blood volume in near infrared noninvasive biochemical sensing can eliminate human tissue background interference, but at the same time the pathlength of subtracted spectrum is unknown. Thus, the model will be insufficiently effective if established directly with pathlength-unknown spectra, which is a big problem for subtracted blood volume spectrometry. In the present paper, a simulated experiment was designed to simulate this issue. The orthogonal signal correction method was proposed to eliminate the influence brought by pathlength. Compared with the PLS model before and after orthogonal signal correction, the root mean square error of cross validation (RMSECV) was from 90.17 mg x dL(-1) down to 31.62 mg x dL(-1), and the correlation coefficient was improved from 0.9787 to 0.9968. The experimental results show that using the orthogonal signal correction method can effectively restrain the interference information of path-length, and improve the prediction precision of calibration model. The conclusion in this paper sets the stage for the practical application of the spectral subtraction approach with different flow blood volume.

To establish the on-line near infrared spectral correction model for the jujube quality of Southern Xinjiang, the main influence factors of online testing results were analyzed, and the corresponding parameters were studied. First of all, the collecting conditions of different jujube were set, such as measurement condition, spectral region, and the parameters of the apparatus. With near infrared spectrometer and self-designed jujube batch collecting attachment, the quality spectrum of jujube was obtained, and combining spectral preprocessing and detection precision, condition parameters were selected. Secondly, through PLS spectrum correction with different modeling parameters and two-dimensional correlation spectroscopy analysis, Brix characteristic spectral parameters were selected. The results showed that with sugar degree central wavelength 9116, 9 418 and 10,500 cm(-1), acquisition resolution 16 cm(-1), and scan number 8, the sugar degree relative error was 8%-10%, the size of single grain jujube spectra was reduced to 1/10 of the original, and the time was reduced to 3 seconds. It was concluded that with the experimental parameters, the spectra were compressed, a primary online correction model was established, and the jujube quality online detection with near infrared spectroscopy was basically realized.

In noninvasive blood glucose measurement, it is difficult to keep the contact area between skin and internal reflectance element uniform while the mid-infrared spectra of human skin are taken, and this would lead to path-length variations. To study the effect of path-length variations on PLSR calibration model, in the present paper, according to the correlation coefficients between path-lengths and glucose concentrations, two PLSR models were achieved respectively and RMSECV were 31.3 and 4.52 mg x dL(-1), RMSEP were 30.3 and 98.7 mg x dL(-1) for the validation set. The results show that the chance correlations between path-lengths and glucose concentrations will lead to calibration models with different accuracy and robustness. This is useful to improving the reliability of noninvasive measurement of blood glucose by mid-infrared spectroscopy.

In the present paper, both the physical characteristics and spectral signatures of southern Xinjiang jujube were studied. With the methods of repetitive adjustment and stepwise refinement, the analysis diagram of jujube quality subdivision and characteristic factors were obtained. In actual practice, the spectra repeatability and quality can be improved by setting an optimum acquisition parameter according to different experimental requirements. Through experiments the characteristic factors of crack browning, luster and compositions were obtained, which demonstrates a distinguishing downing characteristic spectral line at the wave number of 10 170 cm(-1). Through characteristic analysis of jujube NIR spectra, the correspondence between the jujube spectra and their qualities was established, which lays the foundation for jujube qualities' characteristic coding in the future. The application of near-infrared topology method in the quality analysis of southern Xinjiang jujube is cost saving, which has a broad application prospect in establishing the NIR analytical standard and model database sharing of the jujube's quality in the future.

"Digital agriculture" or "precision agriculture" is an important direction of modern agriculture technique. It is the combination of the modern information technique and traditional agriculture and becomes a hotspot field in international agriculture research in recent years. As a nondestructive, real-time, effective and exact analysis technique, near infrared spectroscopy, by which precision agriculture could be carried out, has vast prospect in agrology and gradually gained the recognition. The present paper intends to review the basic theory of near infrared spectroscopy and its applications in the field of agrology, pointing out that the direction of NIR in agrology should based on portable NIR spectrograph in order to acquire qualitative or quantitative information from real-time measuring in field. In addition, NIRS could be combined with space remote sensing to macroscopically control the way crop is growing and the nutrition crops need, to change the current state of our country's agriculture radically.

Objectives: To study the relationship between serum levels of some inflammatory markers and stability of carotid plaques in the patients with carotid plaques and evaluate the ability of each serum marker in identifying vulnerable carotid plaques., Methods: The study included 65 consecutive patients with carotid plaques confirmed by imaging examinations from March 2008 to March 2010. All the patients were classified as stable plaques group (n = 21) and unstable plaques group (n = 44) according to the characteristic findings of the plaques in MRI such as the thickness of fibrous cap, the existence of large lipid core and the intra-plaque hemorrhage. The patients of unstable plaques group were further classified as unruptured plaques group (n = 29) and rupture plaques group (n = 15) according to the integrity of fibrous cap. Serum levels of soluble cluster of differentiation 40 ligand (sCD40L), matrix metalloproteinase 9 (MMP-9) and pregnancy-associated plasma protein A (PAPP-A) were determined by ELISA., Results: Serum levels of sCD40L and MMP-9 in patients of unstable plaques group, unruptured plaques group and rupture plaques group were all significantly enhanced compared to individuals of stable plaques group (SCD40L: χ(2) = 6.45, 12.04 and 16.23, P < 0.01; MMP-9; F = 2.55, 5.10 and 4.69, P < 0.05). Serum levels of PAPP-A in patients of unstable plaques group and rupture plaques group were all significantly enhanced compared to individuals of stable plaques group (χ(2) = 11.71 and 13.55, P < 0.05). Serum levels of PAPP-A in patients of rupture plaques group were significantly enhanced compared to individuals of unruptured plaques group (χ(2) = 13.19, P = 0.000). sCD40L ≥ 673.22 ng/L (OR = 22.47, 95%CI: 2.11 - 239.81, P = 0.010), MMP-9 ≥ 84.09 µg/L (OR = 10.01, 95%CI: 1.74 - 57.78, P = 0.010) and PAPP-A ≥ 0.101 µg/L (OR = 14.29, 95%CI: 2.69 - 75.90, P = 0.002) were all significantly correlated with the vulnerability of carotid plaques., Conclusions: There appear to be a relationship between the serum levels of sCD40L, MMP-9 and PAPP-A and the stability of carotid plaques in patients with carotid plaques. High serum levels of the above-mentioned markers may indicate that the plaques were vulnerable or ruptured.

Soil is the foundation of agricultural production. Rapid analysis of soil nutrients, using near infrared spectral analysis technology, can guide process of agricultural production. Developing near-infrared measuring system with discrete wavelength will change the extensive operation situation of agricultural production. First, the spectra of 85 black soil samples of northeast China, collected by FOSS XDS near-infrared spectrometer were analyzed using the correlation spectra and successive projection algorithm. Then, the characteristic wavelengths of total nitrogen and organic matter were obtained. After that the authors collected the spectra of soil samples using the measuring system with high signal to noise ratio (SNR) that the authors developed. The calibration models for total nitrogen and organic matter were established. The root mean square error of prediction (RMSEP) of total nitrogen and organic matter is 0.019% and 0.36% respectively, and the correlation coefficient of prediction (R(P)) is 0.851 and 0.923, respectively. Experimental results indicate that the characteristic wavelengths for total nitrogen and organic matter can be obtained through the near infrared spectra analyses. The measuring system can be used for soil nutrient analysis and lays the foundation for the industrial applications.

Objective: To study the change of the blood coagulation function of guinea pigs exposed to 16 Hz/120 dB, 16 Hz/125 dB infrasound and to explore the mechanism of circulation system damage., Methods: Seventy-two guinea pigs were divided into 3 groups: the control group, the group exposed to 16 Hz/120 dB infrasound for 1.5 h a day and the group exposed to 16 Hz/125 dB infrasound for 1.5 h a day. Each exposure group was divided into 4 sub-groups (8 guinea pigs a sub-group) which were exposed to infrasound for 1, 7, 14 and 21 d, respectively. The coagulation function and serum nitric oxide (NO) were measured for control group and all sub-groups after exposure to infrasound., Results: The prothrombin time (PT), international normalized ratio (INR) and serum NO of group exposed to 16 Hz/125 dB infrasound were (31.16 ± 3.05) s, 2.53 ± 1.21 and (88.304 ± 52.601) µmol/L, respectively, which were significantly higher than those [(21.36 ± 0.10) s, 1.65 ± 0.07 and (30.943 ± 26.864) µmol/L] of control group (P < 0.05). PT and INR of sub-groups exposed to 16 Hz/125 dB infrasound for 14 and 21 d were significantly higher than those of control group. NO of sub-groups exposed to 16 Hz/125 dB infrasound for 1 week and 2 weeks were significantly higher than that of control group (P < 0.05), but NO of sub-group exposed to 16 Hz/125 dB infrasound for 3 weeks decreased slightly., Conclusion: The blood coagulation function of guinea pigs exposed to 16 Hz/125 dB infrasound decreased, PT and INR may be used as the indexes to assess of blood coagulation function change induced by the infrasound exposure.

To study rapid analysis of cholesterol concentration in human serum with no reagent, near-infrared spectroscopy was used. Applicability of analytical models was studied. Spectra of serum were measured by a FT-NIR spectrometer with 1, 2 and 6. 5 mm optical path length respectively. Partial least-square (PLS) models were calibrated for cholesterol in combination, first overtone and second overtone spectral regions. Root mean square error of prediction (RMSEP) of these models is 0.15, 0.16 and 0.29 mmol x L(-1), and mean percent error of prediction (MPEP) is 2.9%, 3.1% and 4.8%, respectively. To validate applicability of these models, other two groups of serum spectra were measured in one month after the models were calibrated. These two sample groups were calculated using calibrated models. Prediction result of 1 mm model is the best. The result of this experiment indicates that it's possible to calibrate precise models for cholesterol. If model is based on thinner samples, applicability is better.