保定市PM_(2.5)中水溶性离子污染特征及来源分析

为研究保定市PM_(2.5)中水溶性离子污染特征及来源,利用中流量采样器采集保定市2017年秋、冬季10月—2017年12月污染天的PM_(2.5)样品(40个),进行水溶性离子组分分析,并辅以保定市同期气象数据及空气质量数据进行成因探讨。计算离子间相关性,采用离子平衡法衡量大气酸碱度,并对保定市日夜不同时段PM_(2.5)中水溶性离子污染特征进行细节分析,并利用主成分分析法分析PM_(2.5)中水溶性离子来源,且对二次离子来源及气象条件影响进行了深入分析。根据离子之间相关性,推测保定市K^(+)和NO_(3)^(-)、Cl^(−)具有同源性,主要源于生物质燃烧;NH+4在大气中主要以NH_(4)NO_(3)、(NH_(4))_(2)SO_(4)及NH_(4)HSO_(4)等形式存在;推测NO_(3)^(-)及SO_(4)^(2−)两离子主要来源均为工业排放污染物的化学转化;保定市非采暖期大气颗粒物呈酸性,采暖期大气颗粒物呈现碱性。多数水溶性离子含量均呈现夜间高于白天的现象,这一现象可能与气象变化及周围环境影响等诸多因素有关;污染天和清洁天大气PM_(2.5)中二次离子主要来源于移动源;二次离子与湿度均呈正相关趋势,而SO_(4)^(2−)与温度呈负相关趋势;水溶性离子浓度高低依次为NO_(3)^(-)>Na^(+)>SO_(4)^(2−)>Cl^(−)>NH_(4)^(+)>NO_(2)^(-)>Ca^(2+)>K^(+)>F^(−)>Mg^(2+),10—12月PM_(2.5)中多数水溶性离子含量均呈现夜间高于白天的现象;采暖季SOR、NOR均低于非采暖季,二次污染物转化效率较低,这可能与采暖季煤燃烧释放污染物有关;保定市PM_(2.5)水溶性离子主要来源为生物质燃烧、化石燃料燃烧及扬尘源及二次源。

单根锉WaveOne镍钛器械高效治疗弯曲根管的实验研究

目的研究单根锉Wave One镍钛器械治疗弯曲根管的疗效,并与不锈钢K锉、Pro Taper镍钛器械进行比较。方法选取根管弯曲度在20~40°的单根管离体前磨牙60颗,随机分为A、B、C 3组,每组20颗离体牙,3组分别采用Wave One/Crown-down法、K锉逐步后退法及Pro Taper/Crown-down法行根管预备,并采用口腔颌面锥形束计算机体层摄影分别于根管预备前后对离体牙行横向扫描。预备完成后,对3组中的60颗离体牙行冷牙胶侧方加压充填。测量3组中每颗离体牙的根管预备时间、根管充填时间;分析每颗离体牙根管预备前后,根管距根尖孔2、4和6 mm处的根管偏移量和轴中心率,并对以上结果进行统计学分析。结果 A组根管预备时间低于B、C组;在根管充填时间上,A组与C组比较差异无统计学意义(P>0.05),但A组短于B组(P<0.05)。在距根尖孔2、4和6 mm处,A组与B组间的根管偏移量及轴中心率比较,差异有统计学意义(P<0.05);A组与C组比较,差异无统计学意义(P>0.05)。结论与不锈钢K锉及Pro Taper相比,Wave One治疗弯曲根管具有效率高、根管成形效果好的优点,可广泛应用于临床弯曲根管的治疗。

非小细胞肺癌脑转移高危因素研究进展

非小细胞肺癌(non-small cell lung cancer,NSCLC)脑转移是常见的治疗失败模式,发生脑转移的NSCLC患者中位生存时间仅为1个月-2个月。预防性脑照射(prophylactic cranial irradiation,PCI)可延缓脑转移的发生,但对NSCLC患者的生存获益仍存在争议,因此,通过预测脑转移的风险筛选可能从PCI中获益的人群尤为重要。本文就NSCLC脑转移的高危因素进行综述。

Vertical MBE growth of Si fins on sub-10 nm patterned substrate for high-performance FinFET technology

A high quality epitaxial Si layer by molecular beam epitaxy(MBE)on Si(001)substrates was demonstrated to fabricate a channel with low density defects for high-performance Fin FET technology.In order to study the effects of fin width and crystallography orientation on the MBE behavior,a 30 nm thick Si layer was deposited on the top of an etched Si fin with different widths from 10 nm to 50 nm and orientations of 100 and 110.The result shows that a defect-free Si film was obtained on the fin by MBE,since the etching damage was confined in the bottom of the epitaxial layer.In addition,the vertical growth of the epitaxial Si layer was observed on sub-10 nm 100 Si fins,and this was explained by a kinetic mechanism.

Effect of inhibiting miR-155 expression on proliferation and migration of airway smooth muscle cell in patients with COPD

Objective:To investigate the effect of inhibiting miR-155 expression on the proliferation and migration of airway smooth muscle cells(ASMCs)in patients with chronic obstructive pulmonary disease(COPD).Methods:ASMCs were isolated and cultured from 8 patients with COPD(observation group)and 3 patients with benign lung cancer without COPD(control group).The ASMCs were transfected with miR-155 suppression expression plasmid(to detect the expression of miR-155;flow cytometry was used to detect the cell cycler of cell clones;Transwell was used to detect cell migration and invasion;Enzyme-linked immunosorbent aanti-miR-155)and the negative contre;clone formation experiment was used to detect the numbol plasmid(anti-miR-NC),and blank control group was set.Real-time quantitative PCR(RT-qPCR)was usedssay(ELISA)method was used to detect tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)level.Results:The expression level of miR-155 in ASMCs of observation group was significantly higher than that in the control group(P<0.05).The miR-155 expression level in inhibited miR-155 expression group was significantly lower,compared with the negative control group and the blank group(P<0.05).In the inhibited miR-155 expression group,the proportion of G0-G1 phase cells was increased,the proportion of S phase cells was decreased,the number of cell clones,migration,and the number of invasive cells were decreased,and the levels of TNF-αand IL-6 were increased(P<0.05).Conclusions:Inhibiting the expression of miR-155 can inhibit the proliferation and migration of airway smooth muscle cells in COPD patients,and inhibit the release of proinflammatory factors.

The Research of Anti-Swelling and Low Damage Killing Fluid System

In this paper, we introduced reservoir characteristics in Block Xiao-he-long and evaluate the performance of the existing killing fluid system. According to the production requirements, a anti-swelling and low damaging system of chemical agents suitable for this block was optimized, including anti-swelling agent, water lock inhibitor, fluid-loss agent additives, plus a corrosion inhibitor HS-1 developed by in the lab. The system is composed by base liquid (0.7%X + 2.0%KCl +0.05%SY-1+ 0.05%HS-1+2.0% DST-1 dissolved in water) and weighting material (NaCl) with its density adjustable range between 1.0g/ml and 1.2g/ml. Its anti-swelling ratio achieves 53.80%, and the reservoir permeability recovery ratio reaches more than 95.0%.

Altered Local Field Potential Relationship Between the Parafascicular Thalamic Nucleus and Dorsal Striatum in Hemiparkinsonian Rats

The thalamostriatal pathway is implicated in Parkinson's disease(PD); however, PD-related changes in the relationship between oscillatory activity in the centromedian-parafascicular complex(CM/Pf, or the Pf in rodents) and the dorsal striatum(DS) remain unclear.Therefore, we simultaneously recorded local field potentials(LFPs) in both the Pf and DS of hemiparkinsonian and control rats during epochs of rest or treadmill walking. The dopamine-lesioned rats showed increased LFP power in the beta band(12 Hz–35 Hz) in the Pf and DS during both epochs, but decreased LFP power in the delta(0.5 Hz–3 Hz) band in the Pf during rest epochs and in the DS during both epochs, compared to control rats. In addition,exaggerated low gamma(35 Hz–70 Hz) oscillations after dopamine loss were restricted to the Pf regardless of the behavioral state. Furthermore, enhanced synchronization of LFP oscillations was found between the Pf and DS after the dopamine lesion. Significant increases occurred in the mean coherence in both theta(3 Hz–7 Hz) and beta bands,and a significant increase was also noted in the phase coherence in the beta band between the Pf and DS during rest epochs. During the treadmill walking epochs, significant increases were found in both the alpha(7 Hz–12 Hz)and beta bands for two coherence measures. Collectively,dramatic changes in the relative LFP power and coherence in the thalamostriatal pathway may underlie the dysfunction of the basal ganglia-thalamocortical network circuits in PD, contributing to some of the motor and non-motor symptoms of the disease.

Perturbations of Moore–Penrose Metric Generalized Inverses of Linear Operators in Banach Spaces

In this paper, the perturbations of the Moore-Penrose metric generalized inverses of linear operators in Banach spaces are described. The Moore Penrose metric generalized inverse is homo- geneous and nonlinear in general, and the proofs of our results are different from linear generalized inverses. By using the quasi-additivity of Moore-Penrose metric generalized inverse and the theorem of generalized orthogonal decomposition, we show some error estimates of perturbations for the single- valued Moore-Penrose metric generalized inverses of bounded linear operators. Furthermore, by means of the continuity of the metric projection operator and the quasi-additivity of Moore-Penrose metric generalized inverse, an expression for Moore-Penrose metric generalized inverse is given.

ntravitreal Ranibizumab for Aggressive Posterior Retinopathy of Prematurity

Retinopathy ofprematurity （ROP） is a proliferative disease that affects infants of young gestational age （GA） and low birth weight （BW）. Aggressive posterior ROP （AP-ROP） is a rapidly progressing and severe presentation of ROP. It is characterized as posterior location （zone 1 or posterior zone I1）, Stage 3, and with plus disease （arterial tortuosity and venous dilation）. It can quickly lead to retinal detachment and blindness if not treated in time.

LILRB4 ITIMs mediate the T cell suppression and infiltration of acute myeloid leukemia cells

We recently demonstrated that leukocyte Ig-like receptor 4(LILRB4)expressed by monocytic acute myeloid leukemia(AML)cells mediates T-cell inhibition and leukemia cell infiltration via its intracellular domain.The cytoplasmic domain of LILRB4 contains three immunoreceptor tyrosine-based inhibitory motifs(ITIMs);the tyrosines at positions 360,412,and 442 are phosphorylation sites.Here,we analyzed how the ITIMs of LILRB4 in AML cells mediate its function.Our in vitro and in vivo data show that Y412 and Y442,but not Y360,of LILRB4 are required for T-cell inhibition,and all three ITIMs are needed for leukemia cell infiltration.We constructed chimeric proteins containing the extracellular domain of LILRB4 and the intracellular domain of LILRB1 and vice versa.The intracellular domain of LILRB4,but not that of LILRB1,mediates T-cell suppression and AML cell migration.Our studies thus defined the unique signaling roles of LILRB4 ITIMs in AML cells.

Assessment and improvement of Noah-MP for simulating water and heat exchange over alpine grassland in growing season

Alpine grassland is the main ecosystem of the Tibetan Plateau(TP),thus accurate simulation of water and heat exchange in the grassland will significantly enhance the understanding of the land-atmosphere interaction process on the TP.In this study,we assessed and improved the ensemble numerical simulations of the community Noah land surface model with multiparameterization options(Noah-MP)by using observations collected from four alpine grassland observation sites.The four observation sites belong to the upper Heihe River Basin Integrated Observatory Network located in the northeastern part of the TP.First,an ensemble of 1008 numerical simulation experiments,based on multiparameterization options of seven physical processes/variables in the Noah-MP,was carried out for the vegetation growing season.The Taylor skill score was then used to assess the model performance and select the optimal combination of parameterization options for a more exact simulation of the water and heat exchange in alpine grassland.The accuracy of Noah-MP simulation was further improved by introducing new parameterizations of thermal roughness length,soil hydraulic properties,and vertical root distribution.It was found that:(1)Simulation of water and heat exchange over alpine grassland in the growing season was mainly affected by the parameterizations of dynamic vegetation,canopy stomatal resistance,runoff and groundwater dynamics,and surface exchange coefficient for heat transfer.Selection of different parameterization options for these four physical processes/variables led to large differences in the simulation of water and heat fluxes.(2)The optimal combination of parameterization options selected in the current Noah-MP framework suffered from significant overestimation of sensible heat flux(H)and underestimation of soil moisture(θ)at all observation sites.(3)The overestimation of H was significantly improved by introducing a new parameterization of thermal roughness length.Furthermore,the underestimation ofθwas resolved by introducing a new parameterization of soil hydraulic properties that considered the organic matter effect and a new vertical distribution function for the vegetation root system.The results of this study provide an important reference for further improving the simulation of water and heat exchange by using the land surface model in alpine grassland.

Correction to: LILRB4 ITIMs mediate the T cell suppression and infiltration of acute myeloid leukemia cells

In this article,published online on 7 November 2019,there was an unintended error during image processing of Fig.1a and Fig.6c leading to wrong pictures to appear.These pictures have now been replaced with the appropriate pictures that were generated for this experiment.The corrected Fig.1 and Fig.6 are shown here.The conclusion made from the experiments remains unaltered.The inconvenience caused by this error is deeply regretted.