Characteristics of aerosol aminiums over a coastal city in North China: Insights from the divergent impacts of marine and terrestrial influences

Aminium ions, as crucial alkaline components within fine atmospheric particles, have a notable influence on new particle formation and haze occurrence. Their concentrations within coastal atmosphere depict considerable variation due to the interplay of distinctive marine and terrestrial sources, further complicated by dynamic meteorological conditions. This study conducted a comprehensive examination of aminiums ions concentrations, with a particular focus on methylaminium (MMAH+), dimethylaminium (DMAH+), trimethylaminium (TMAH+), and triethylaminium (TEAH+) within PM2.5, over varying seasons (summer, autumn, and winter of 2019 and summer of 2021), at an urban site in the coastal megacity of Qingdao, Northern China. The investigations revealed that the total concentration of particulate aminium ions (∑Aminium) was 21.6 ± 23.6 ng/m3, exhibiting higher values in the autumn and winter compared to the two summer periods. Considering diurnal variations during autumn and winter, concentrations of particulate aminium ions (excluding TEAH+) exhibited a slight increase during the day compared to night, with a notable peak during the morning hours. However, it was not the case for TEAH+, which was argued to be readily oxidized by ambient oxidants in the afternoon. Additionally, the ∑Aminium within the summer demonstrated markedly elevated levels during the day compared to night, potentially attributed to daytime sea fog associated with sea-land breeze interactions. Positive matrix factorization results indicate terrestrial anthropogenic emissions, including vehicle emission mixed with road dust and primary pollution, as the primary sources of MMAH+ and DMAH+. Conversely, TMAH+ was predominantly emitted from agricultural and marine sources. With the dominance of sea breeze in summer, TMAH+ was identified as a primary marine emission correlated with sea salt, while MMAH+, DMAH+, and TEAH+ were postulated to undergo secondary formation. Furthermore, a notable inverse correlation was observed between TMAH+ and methanesulfonate in PM2.5, consistent with dynamic emissions of sulfur-content and nitrogen-content gases reported in the literature.

Impact of COVID-19 emission reduction on dust aerosols and marine chlorophyll-a concentration

The long-range transport of dust aerosols plays a crucial role in biogeochemical cycling, and dust deposition is an important source of nutrients for marine phytoplankton growth. To study the impact of COVID-19 emission reduction on dust aerosols and marine chlorophyll-a (Chl-a) concentration, we selected two similar dust processes from the COVID-19 period (10-15 March 2020) and the non-COVID-19 period (15-20 March 2019) using the Euclidean distance calculation method in combination with the HYSPLIT model and multiple satellite data. During the non-COVID-19 period, the proportion of dust was 6.68 %, approximately half that of the COVID-19 period. Meanwhile, the proportion of polluted dust during the non-COVID-19 period was 4.95 %, which was more than tenfold compared to the COVID-19 period. Furthermore, noticeable discrepancies in Chl-a concentration were observed between the two periods. In the non-COVID-19 period, the maximum daily deposition of dust aerosols can reach 16.23 mg/m2, resulting in a 39-85 % increase in Chl-a concentration. However, during COVID-19 period, the maximum daily dust deposition can reach 33.33 mg/m2, while the increase in Chl-a concentration was <30 %. This conclusion suggests that reductions in anthropogenic emissions during the COVID-19 period have influenced the nutrient content of dust aerosols, resulting in a lesser impact on Chl-a concentrations in the ocean.

Unveiling the overlooked direct emissions of particulate organic nitrates from ship

Particulate organic nitrates (pONs) have drawn growing interests due to their effects on nitrogen cycling, air pollution, and regional climate. While secondary formation is typically considered as the major source of pONs, direct emissions from various sources remain poorly explored. Ship exhausts have been known as an important source of reactive nitrogen species, yet pONs emissions from ship have been rarely characterized. In this study, we conducted atmospheric measurement of pONs during a ship-based cruise measurement campaign in the East China Sea and also emission measurement of pONs from ship exhausts. During the ship-based cruise, total five typical kinds of pONs were determined and the average total concentrations of five pONs were 479 ± 193 and 250 ± 139 ng m-3 when sampling was influenced by ship emissions or not, respectively, indicating the notable impact of ship exhaust plumes on ambient pONs. Further, five typical pONs were successfully identified and quantified from ship exhausts, with the average total concentration of 1123 ± 406 μg m-3. The much higher pONs levels in ship exhausts than in ambient particulate matters demonstrated ship emission as an important source for pONs. Additionally, their emission factors from ship exhausts were determined as at a range of 0.1-12.6 mg kWh-1. The chemical transport model simulations indicate that direct pONs emissions from ship exert a significant contribution to atmospheric pONs, especially in the clean marine atmosphere. These findings provide compelling evidence for direct emission of pONs from ship and its considerable effects. We call for further studies to better characterize the direct pONs emissions from ship and other potential sources, which should be incorporated into global and regional models.

An Immune-Related Gene Prognostic Prediction Risk Model for Neoadjuvant Chemoradiotherapy in Rectal Cancer Using Artificial Intelligence

PURPOSE/OBJECTIVE(S)

To develop and validate an immune-related gene prognostic model (IRGPM) that can predict disease-free survival (DFS) in patients with locally advanced rectal cancer (LARC) who received neoadjuvant chemoradiotherapy and to clarify the immune characteristics of patients with different prognostic risks.

MATERIALS/METHODS

In this study, we obtained transcriptomic and clinical data from the Gene Expression Omnibus (GEO) database and rectal cancer database of West China Hospital. Genes in the RNA immune-oncology panel were extracted. Elastic net was used to identify the immune-related genes that significantly affected the DFS of patients. A prognostic risk model (IRGPM) for rectal cancer was constructed with the random forest method. The prognostic risk score was calculated by the model, and the patients were divided into high- and low-risk groups according to the median risk score. Immune characteristics were analyzed and compared between the high- and low-risk groups.

RESULTS

A total of 407 LARC samples were used in this study. A 20-gene signature was identified by elastic net and was found to be significantly correlated with DFS. The IRGPM was constructed on the basis of the 20 immune-related genes. Kaplan‒Meier survival analysis showed poorer 5-year DFS in the high-risk group than in the low-risk group, and the receiver operating characteristic (ROC) curve suggested good model prediction (areas under the curve (AUCs) of 0.87, 0.94, 0.95 at 1, 3, and 5 years, respectively). The model was validated in the GSE190826 cohort (AUCs of 0.79, 0.64, and 0.63 at 1, 3, and 5 years, respectively) and the cohort from our institution (AUCs of 0.64, 0.66, and 0. 64 at 1, 3, and 5 years, respectively). The differentially expressed genes between the high- and low-risk groups were enriched in cytokine‒cytokine receptor interactions. The patients in the low-risk group had higher immune scores than the patients in the high-risk group. Subsequently, we found that activated B cells, activated CD8 T cells, central memory CD8 T cells, macrophages, T follicular helper cells and type 2 helper cells were more abundant in the low-risk group. Moreover, we compared the expression of immune checkpoints and found that the low-risk group had a higher PDCD1 expression level.

CONCLUSION

The IRGPM, which was constructed based on the random forest and elastic net methods, is a promising method to distinguish DFS in LARC patients treated with a standard strategy. The low-risk group identified by IRGPM was characterized by the activation of adaptive immunity in tumor microenvironment.

Important Roles and Formation of Atmospheric Organosulfates in Marine Organic Aerosols: Influence of Phytoplankton Emissions and Anthropogenic Pollutants

Organosulfates (OSs) could be potentially important compounds in marine organic aerosols, while their formation in marine atmospheres is far from clear due to a lack of cruise observations. In this work, shipboard atmospheric observations were conducted over the Yellow Sea and Bohai Sea to investigate the abundance and formation of biogenic isoprene/monoterpene-OSs in marine aerosols. The quantified OSs and NOSs accounted for 0.04-6.9% of marine organic aerosols and were 0.07-2.2% of the non-sea-salt (nss) sulfate in terms of sulfur content. Isoprene-related (nitrooxy-)OSs occupied 27-87% of the total quantified OSs, following the abundance order of summer > autumn > spring or winter. This order was driven by the marine phytoplankton biomass and sea surface temperature (SST), which controlled the seawater and atmospheric isoprene concentration levels. Under the severe impacts of anthropogenic pollutants from the East Asia continent in winter, monoterpene nitrooxy-OSs, generated with NO_x involved in, increased to 34.4 ± 35.5 ng/m³ and contributed 68% of the quantified (nitrooxy-)OSs. Our results highlight the notable roles of biogenic OSs in marine organic aerosols over regions with high biological activity and high SST. The formation of biogenic OSs and their roles in altering marine aerosol properties calls for elaboration through cruise observations in different marine environments.

[Associations between various lipid components and premature myocardial infarction: a cross-sectional study]

Objective: Hyperlipidemia is closely related to premature acute myocardial infarction (AMI). The present study was performed to explore the correlation between various blood lipid components and the risk of premature AMI. Methods: This is a cross-sectional retrospective study. Consecutive patients with acute ST-segment elevation myocardial infarction (STEMI), who completed coronary angiography from October 1, 2020 to September 30, 2022 in our hospital, were enrolled and divided into premature AMI group (male<55 years old, female<65 years old) and late-onset AMI group. Total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), non-HDL-C, lipoprotein (a) (Lp (a)), apolipoprotein B (ApoB), apolipoprotein A-1 (ApoA-1), non-HDL-C/HDL-C and ApoB/ApoA-1 were analyzed. The correlation between the above blood lipid indexes and premature AMI was analyzed and compared by logistic regression, restricted cubic spline and receiver operating characteristic curve (ROC). Results: A total of 1 626 patients with STEMI were enrolled in this study, including 409 patients with premature AMI and 1 217 patients with late-onset AMI. Logistic regression analysis showed that the risk of premature AMI increased significantly with the increase of TG, non-HDL-C/HDL-C, non-HDL-C, ApoB/ApoA-1, TC and ApoB quintiles; while LDL-C, ApoA-1 and Lp (a) had no significant correlation with premature AMI. The restricted cubic spline graph showed that except Lp (a), LDL-C, ApoA-1 and ApoB/ApoA-1, other blood lipid indicators were significantly correlated with premature AMI. The ROC curve showed that TG and non-HDL-C/HDL-C had better predictive value for premature AMI. Inconsistency analysis found that the incidence and risk of premature AMI were the highest in patients with high TG and high non-HDL-C/HDL-C. Conclusion: TG, non-HDL-C/HDL-C and other blood lipid indexes are significantly increased in patients with premature AMI, among which TG is the parameter, most closely related to premature AMI, and future studies are needed to explore the impact of controlling TG on incidence of premature AMI.

Dual-channel compressed ultrafast photography for Z-pinch dynamic imaging

The compressed ultrafast photography (CUP) can capture non-repetitive time-evolving events at 7 × 10¹³ fps, which is anticipated to find a diverse range of applications in physics, biomedical imaging, and materials science. The feasibility of diagnosing ultrafast phenomenon of Z-pinch by using the CUP has been analyzed in this article. Specifically, a dual-channel CUP design has been adopted for acquiring high quality reconstructed images and the strategies of identical masks, uncorrelated masks, and complementary masks have been compared. Furthermore, the image of the first channel was rotated by 90° to balance the spatial resolution between the sweep direction and the non-sweep direction. Both five synthetic videos and two simulated Z-pinch videos were chosen as the ground truth to validate this approach. The average peak signal to noise ratio of the reconstruction results is 50.55 dB for the self-emission visible light video and 32.53 dB for the laser shadowgraph video with unrelated masks (rotated channel 1). The simulation results show that the time-space-evolving process of plasma distribution can be well retold, and the phenomenon of plasma instability can be accurately diagnosed by the dual-channel CUP with unrelated masks (rotated channel 1). This study may promote the practical applications of the CUP in the field of accelerator physics.

PM2.5 source apportionment identified with total and soluble elements in positive matrix factorization

Source apportionments of urban aerosols identified with positive matrix factorization (PMF) are sensitive to input variables. So far, total elements were frequently included as effective factors in PMF-based source apportionment. We investigated the advances to involve soluble parts of elements in the source apportionment with four data sets of PM_2.5 composition observed at a coastal city (Qingdao) in northern China: water-soluble ions plus organic and elemental carbon (IC set), the IC set plus total elements (ICTE set), the IC set plus soluble elements (ICSE set), and the IC set plus both total elements and soluble elements (ICAE set). The apportionments of six sources, including secondary sulfate, secondary nitrate, secondary oxalate, sea salt, biomass burning and dust, were identified with the IC set. In comparison, pollutants from vehicle + coal combustion, ship emissions, waste incineration and industrial activities were also identified with the ICTE, ICSE, or ICAE sets. We found that the PMF solutions of the ICAE set could distinguish aged and fresh dust, and identify fly ash and aged pollutants from industrial sources. The profiles and corresponding time series of vehicle + coal combustion, secondary aerosols, ship emissions, sea salt, and biomass burning emissions identified with the four data sets were very similar, while discrepancies were encountered for waste incineration, dust, and industrial sources. These results indicate the benefits and potentials with total and soluble elements involved in PMF-based source apportionments.

Association between Frailty Assessed Using Two Electronic Medical Record-Based Frailty Assessment Tools and Long-Term Adverse Prognosis in Older Critically Ill Survivors

OBJECTIVES

Frailty has become an independent risk factor for adverse outcomes in critically ill patients. This study aimed to explore the predictive ability of two electronic medical record-based frailty assessment tools, the Hospital Frailty Risk Score (HFRS) and Frailty Index based on physiological and laboratory tests (FI-lab), for long-term adverse prognosis in older critically ill survivors.

DESIGN

Retrospective observational study.

SETTING AND PARTICIPANTS

9,082 critically ill survivors aged ≥ 65 years.

MEASUREMENTS

The HFRS and the 33-item FI-lab were constructed based on the published literature. Cox and logistic regression models assessed the association between frailty and 1-year mortality and post-discharge care needs.

RESULTS

2,586 patients died within 1 year of follow-up. In fully adjusted models, frailty assessed using both the HFRS (per point, hazard ratio [HR] 1.06, 95% confidential interval [CI] 1.05-1.06; intermediate frailty risk, HR 2.00, 95% CI 1.78-2.25; high frailty risk, HR 3.06, 95% CI 2.68-3.50) and FI-lab (per 0.01 points, HR 1.03, 95% CI 1.03-1.03; intermediate frailty risk, HR 1.59, 95% CI 1.44-1.76; high frailty risk, HR 2.30, 95% CI 2.06-2.57) was associated with mortality. Addition of frailty indicators improved the predictive validity of the Sequential Organ Failure Assessment score for mortality (HFRS alone ∆ C-index 0.034; FI-lab alone ∆ C-index 0.016; HFRS and FI-lab combined ∆ C-index 0.042). The HFRS but not the FI-lab was associated with higher probability of post-discharge care needs.

CONCLUSION

Both the HFRS and FI-lab could independently predict 1-year mortality in older critically ill survivors. Adding the HFRS to the SOFA score model improved it more than adding the FI-lab. The greatest improvement was achieved when both frailty indicators were used together. These findings suggest that electronic medical record-based frailty assessment methods can be useful tools for predicting long-term outcomes in older critically ill patients.

Investigation of a haze-to-dust and dust swing process at a coastal city in northern China part I: Chemical composition and contributions of anthropogenic and natural sources

The long retention of dust air masses in polluted areas, especially in winter, may efficiently change the physicochemical properties of aerosols, causing additional health and ecological effects. A large-scale haze-to-dust weather event occurred in the North China Plain (NCP) region during the autumn-to-winter transition period in 2018, affecting the coastal city Qingdao several times between Nov. 27th and Dec. 1st. To study the evolution of the pollution process, we analyzed the chemical characteristics of PM_2.5 and PM_10-2.5 and source apportionments of PM_2.5 and PM_10, The dust stagnated around NCP and moved out and back to the site, noted as dust swing process, promoting SO₄^2- formation in PM_2.5 and NO₃^- formation in PM_10-2.5. Source apportionments were analyzed using the Positive Matrix Factorization (PMF) receptor model and weighted potential source contribution function (WPSCF). Before the dust invasion, Qingdao was influenced by severe haze; waste incineration and coal burning were the major contributors (~80 %) to PM_2.5, and the source region was in the southwest of Shandong Province. During the initial dust event, mineral dust and the mixed factor of dust and sea salt were the major contributors (46.0 % of PM_2.5 and 86.5 % of PM₁₀). During the polluted dust period, the contributions of regional transported biomass burning (22.3 %), vehicle emissions (20.8 %), and secondary aerosols (33.8 %) to PM_2.5 from the Beijing-Tianjin-Hebei region significantly increased. The secondary aerosols source was more regional than that of vehicle emissions and biomass burning and contributed considerably to PM₁₀ (30.8 %) during the dust swing process. Our findings demonstrate that environmental managers should consider the possible adverse effects of winter dust on regional and local pollution.

Numerical study of the amplification effects of cold-front passage on air pollution over the North China Plain

Cold-front systems provide scavenging mechanisms for air pollution in the North China Plain (NCP), but the transport of pollutants with cold fronts aggravates air quality downstream. The impact of cold fronts on PM_2.5 concentrations over the NCP during 8-14 December 2019 was studied using the WRF-Chem model. Results indicate that cold fronts directly influence PM_2.5 concentration through regional transport of pollutants and adjustment of meteorological systems, and they indirectly affect air quality by influencing aerosol-radiation interaction. Pollutants affecting downstream areas may be transported to altitudes of ~3 km along the frontal surface, with near-surface PM_2.5 concentrations increasing temporarily at up to 15 μg·m^-3·h^-1 behind the surface frontal line owing to the inversion layer triggered by the oblique frontal surface. The transport process plays an essential role in affecting air pollution levels, more than vertical mixing and chemical reaction processes. Changes in the meteorological system (eastward shift of the high-pressure center) occurring with the passage of cold fronts facilitate the accumulation and transport of pollutants in the NCP, reducing air quality in the western and northern NCP. Cold fronts may also indirectly exacerbate near-surface pollutant diffusion conditions by affecting solar radiation incidence, with a reduction of the 2-m temperature by as much as 1 °C, increasing near-surface (<1 and 0.5 km agl on the pre- and post-frontal sides, respectively) PM_2.5 concentrations by up to 40 μg·m^-3, while reducing upper-layer concentrations by up to 30 μg·m^-3. This study emphasizes the amplification effect of cold fronts on air pollution, with inter-regional cooperation being essential in improving air quality in the NCP region.

The striking effect of vertical mixing in the planetary boundary layer on new particle formation in the Yangtze River Delta

New particle formation (NPF) induces a sharp increase in ultrafine particle number concentrations and potentially acts as an important source of cloud condensation nuclei (CCN). As the densely populated area of China, the Yangtze River Delta (YRD) region shows a high frequency of observed NPF events at the ground level, especially in spring. Although recent observational studies suggested a possible connection between NPF at the higher altitudes and ground level, the role played by vertical mixing, particularly in the planetary boundary layer (PBL) is not fully understood. Here we integrate measurements in Nanjing on 15-20 April 2018, and the NPF-explicit Weather Research and Forecast coupled with chemistry (WRF-Chem) model simulations to better understand the governing mechanisms of the NPF and CCN. Our results indicate that newly formed particles at the boundary layer top could be transported downward by vertical mixing as the PBL develops. A numerical sensitivity simulation created by eliminating aerosol vertical mixing suppresses both the downward transport of particles formed at a higher altitude and the dilution of particles at the ground level. The resulting higher Fuchs surface area at the ground level, together with the lack of downward transport, yields a sharp weakening of NPF strength and delayed start of NPF therein. The aerosol vertical mixing, therefore, leads to a more than double increase of surface CN_10-40 and a one third decrease of boundary layer top CN_10-40. Additionally, the continuous growth of nucleated ultrafine particles at the boundary layer top is strongly steered by the upward transport of condensable gases, with close to half increase of particle number concentrations in Aitken mode and CCN at a supersaturation rate of 0.75%. The findings may bridge the gap in understanding the complex interaction between PBL dynamics and NPF events, reducing the uncertainty in assessing the climate impact of aerosols.

Characterizing the distinct modulation of future emissions on summer ozone concentrations between urban and rural areas over China

Previous studies on ozone pollution primarily focus on the characterization of ozone on a large regional scale, yet much less attention has been paid towards the contrast between urban and surrounding suburban-rural areas. As anthropogenic emissions are projected to decrease in the coming decades, the evolutions of ozone concentrations over urban and suburban-rural areas are compared using the Community Multiscale Air Quality (CMAQ) model coupled with the Weather Research and Forecasting (WRF). The top 25 city clusters are firstly identified across China based on the amount of NO_x emissions and population size. At present, the averages of maximum daily 8-h (MDA8) ozone concentrations over the suburban-rural areas (65.74 ppbv) among these city clusters are higher than the corresponding urban areas (62.00 ppbv). The projections in 2050s depend on the scenarios. Under the Shared Socioeconomic Pathways (SSPs) scenarios such as SSP1-2.6, SSP2-4.5 and SSP5-8.5 indicative of primary decreases in anthropogenic emissions, the mean MDA8 ozone concentrations in suburban-rural areas decrease more than urban areas. In contrast, the gap of higher MDA8 ozone concentrations in suburban-rural than urban areas increases under SSP3-7.0 concomitant with increase in anthropogenic emissions. The strongest response to emission changes is found in SSP1-2.6, in which anthropogenic emission reduction leads to lower MDA8 ozone concentrations in the suburban-rural than urban areas, reversing the present state of higher ozone concentrations in the suburban-rural areas. The feature abovementioned regarding changes of mean MDA8 ozone concentrations is largely reproduced in the response of ozone exceedance. The finding highlights different efficacies of anthropogenic emissions in urban from suburban-rural areas. In a region like China where the population density is much higher in urban than suburban-rural regions, the benefit of ozone reduction due to large emission reductions (e.g., SSP1-2.6) is diminished to some extent because the effect is larger in suburban-rural areas.

A high-speed radiation imaging system based on liquid scintillator filled capillary arrays

A high-speed radiation imaging system based on an image converter of liquid scintillator filled capillary arrays has been developed, which is sensitive to x rays, gamma rays, and neutrons. This imaging system has advantages of both high spatial resolution and high sensitivity because increasing the thickness of the image converter only leads to little deterioration on imaging resolution. The capillary arrays have dimensions of 150 mm diameter and 50 mm thickness, with 100 µm diameter of each capillary. The fluorescence decay time of the filled liquid scintillator based on the mixture of p-xylene and 2,5-diphenyloxazole has been evaluated to be ∼3 ns with the single photon method under the gamma ray excitation. The spatial resolution has been experimentally evaluated to be about 1.15 and 0.6 mm, under excitation of x rays and neutrons, respectively. The imaging system has been applied for diagnosing the dynamic x-ray spot generated by the rod pinch. Two frames in single shot with 15 ns temporal resolution and 20 ns inter-frame separation time have been obtained, which show the spatiotemporal distribution of the electrons bombarding the tungsten rod, indicating the ability of this imaging system in diagnosing dynamic radiation objects. In addition, the technique of capillary arrays provides a promising path for applications of advanced liquid scintillators in the field of radiation imaging.

Study of the intentional replantation procedure used to treat a tooth with a palatogingival groove: A case report

In order to clarify the prognosis of intentional replantation used for palatogingival groove treatment for long-term follow-up observation, the case of a patient with a maxillary lateral incisor with palatogingival groove was investigated. The intentional replantation was carried out to preserve the tooth. The periodontal pocket and the apical bone defect were almost completely repaired at 12-month follow-up. However, the infection was reoccurred after 25-month follow-up examinations. The infected tooth was extracted, of which the root was investigated by histological analysis. Therefore, the reason of the replant failure and the pathways of bacterial infection was investigated.

Key words:Palatogingival groove, intentional tooth replantation, bacterial infection, maxillary lateral incisor.

Optimal estimation of initial concentrations and emission sources with 4D-Var for air pollution prediction in a 2D transport model

Attributing sources of air pollution events by deploying an efficient observational network is an important and interesting problem in air quality control and forecast studies, but it is very challenging. In order to estimate the sensitivities of pollution events to emission sources, a comprehensive framework is built based on a horizontal 2-dimensional transport model and its adjoint in solving this problem. In an analysis of an idealized air pollution event of PM_2.5 over the region of North China, an objective function is defined to optimally estimate the initial concentrations and emission sources through a series of minimization procedures. Results by means of the 4-dimensional variational approach show that, with the optimal initial conditions and emission sources, the model can successfully forecast the pollution event in a few days. The optimal observing network based on sensitivity analysis takes only one third of the cost but greatly retains predictability skill compared to the full-grid observing system, while nearly no predictability skill is detectable if the same number of observational sites is randomly deployed. We evaluate air pollution predictability in the point of focusing on to what degree the root mean square errors between the modeled concentration and the targeted air pollution are limited by the optimal observational network. Results show that air pollution predictability in association with the optimal observational network is limited in the time scales about 6 days. With the high efficiency and in an economic fashion, such a sensitivity-based optimal observing system holds promise for accurately predicting an air pollution event in the targeted area once the adjoint and variational procedure of a realistic atmosphere model including transport and chemical processes is performed.

Liposome-paclitaxel and carboplatin combination chemoradiotherapy for patients with locally advanced esophageal squamous cell carcinoma

PURPOSE

The aim of this study was to evaluate the efficacy of liposome-paclitaxel and carboplatin combination chemoradiotherapy for patients with locally advanced esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

Seventy-nine consecutive patients treated with liposome-paclitaxel based concurrent chemoradiotherapy between January 2015 and December 2019 at Cancer hospital of the University of Chinese Academy of Sciences (Zhejiang cancer hospital) were enrolled in this study. The overall response, toxicities, progression-free survival and overall survival were analyzed with SPSS software.

RESULTS

A total of 302 cycles of weekly chemotherapy were delivered, with a median 4 courses. After concurrent chemoradiotherapy (CCRT), the efficacy was classified as CR in 4 cases (5.1%), PR in 22 cases (28.2%) and SD in 51 cases (65.4%). The median PFS and OS time were 18.2 months and 23.4 months. The 3-year PFS and OS rates were 45.1% and 43.6%, respectively.

CONCLUSIONS

Liposome-paclitaxel and carboplatin concurrent with radiotherapy is a safe and effective modality for locally advanced ESCC. Further clinical investigation are warranted to evaluate the efficacy of this regimen.

The climate impact on atmospheric stagnation and capability of stagnation indices in elucidating the haze events over North China Plain and Northeast China

In this study, the spatial pattern and temporal evolution of PM_2.5 over North China Plain (NCP) and Northeast China (NEC) during 2014-2018 was investigated. The annual mean PM_2.5 shows clear decreasing trends over time, but the seasonal mean PM_2.5 as well as the seasonal total duration and frequency of haze days shows large inter-annual fluctuation. Based on the atmospheric stagnation index (ASI), this study examined the correlation between ASI and haze events over NCP and NEC. Detailed analysis indicates that location dependency exists of ASI in the capability of capturing the haze events, and the ability is limited in NCP. Therefore, we first propose two alternative methods in defining the ASI to either account for the lag effect or enlarge the threshold value of wind speed at 500 hPa. The new methods can improve the ability of ASI to explain the haze events over NEC, though marginal improvement was achieved in NCP. Furthermore, this study constructed the equation based on the boundary layer height and wind speed at 10-meter, apparently improving the ability in haze capture rate (HCR), a ratio of haze days during the stagnation to the total haze days. Based on a multi-model ensemble analyses under Representative Concentration Pathway (RCP) 8.5, we found that by the end of this century, climate change may lead to increases in both the duration and frequency of wintertime stagnation events over NCP. In contrast, the models predict a decrease in stagnant events and the total duration of stagnation in winter over NEC.

Ship emission of nitrous acid (HONO) and its impacts on the marine atmospheric oxidation chemistry

Nitrous acid (HONO) is an important reservoir of the hydroxyl radical (OH) and thus plays a central role in tropospheric chemistry. Exhaust from engines has long been known as a major primary source of HONO, yet most previous studies focused on vehicle emissions on land. In comparison, ship emissions of HONO have been rarely characterized, and their impacts on the tropospheric oxidation chemistry have not been quantified. In this study, we conducted cruise measurements of HONO and related species over the East China Sea. Contrasting air masses from pristine marine background air to highly polluted ship plumes were encountered. The emission ratio of ΔHONO/ΔNO_x (0.51 ± 0.18%) was derived from a large number of fresh ship plumes. Using the in-situ measured emission ratio, a global ship emission inventory of HONO was developed based on the international shipping emissions of NO_x in the Community Emission Data System inventory. The global shipping voyage emits approximately 63.9 ± 22.2 Gg yr^-1 of HONO to the atmosphere. GEOS-Chem modelling with the addition of ship-emitted HONO showed that HONO concentrations could increase up to 40-100% over the navigation areas, leading to about 5-15% increases of primary OH production in the early-morning time. This study elucidates the potentially considerable effects of ship HONO emissions on the marine atmospheric chemistry, and calls for further studies to better characterize the ship emissions of HONO and other reactive species, which should be taken into account by global and regional models.

Characteristics and sources of PM2.5 with focus on two severe pollution events in a coastal city of Qingdao, China

In this study, the seasonal mean PM_2.5 concentration in Qingdao, a coastal city, during 2014-2018 was first analyzed and the winter, in particular of 2015, showed the highest concentration. To elucidate the sources and control factors of PM_2.5, three dimensional model Weather Research and Forecasting (WRF), Community Multiscale Air Quality model (CMAQ), as well as Flexible Particle model (FLEXPART), were used. During December 2015 and January 2016, modeling results showed that the mean contribution to PM_2.5 mass concentrations from local emissions in Qingdao was 25%, and the transport from north and west accounted for almost half. Over the two episodically polluted periods (29-31 December 2015; 15-17 January 2016), the local emissions in Qingdao surprisingly contributed to only 18% and 24% to PM_2.5 mass concentrations, respectively, indicating the dominant contributions from other regions, such as areas outside Qingdao in Shandong and Beijing-Tianjin-Hebei (BTH). The results show the sources region and contribution may vary remarkably along with the change in the pathways of the air parcel, inferred by the FLEXPART, while the near-surface PM_2.5 enhancement is largely caused by downward vertical advection and enhanced aerosol chemistry reactions, accompanied by simultaneous drop in the boundary layer height. This study also reveals that the transport contribution is sensitive to the air parcel trajectories. We, therefore, recommend the efficient emission control based on transport trajectories in short-term air quality improvement in Qingdao.

Study Frequency Shift Evaluation of Ultrasound in Fresh and Frozen-thawed Tissues of Cryosurgery by AR Model

BACKGROUND

Noninvasive monitoring of cryosurgery is important for performing precise monitoring of the freezing process in situ and evaluating postoperative effects after therapy. One potential approach is to monitor the normal and freeze-thawed tissues through ultrasonic backscattered signal processing.

OBJECTIVE

A noninvasive method for cryosurgery monitoring based on the analysis of microstructural characteristics of in vitro porcine liver tissues at different state including normal and freeze-thawed tissues by estimating the center frequency of scatterers (CFS) using the autoregressive (AR) cepstrum of ultrasonic backscattered signals.

MATERIALS AND METHODS

The method is based on the discrete scattering model described in the tissue characterization literature and the observation that most biological tissues are semi-regular scattering lattices. A total of ten in vitro porcine liver samples were used and freeze by water bath in the experiments.

RESULTS

Experimental results show that the CFS in porcine liver tissues decreases after pre-frozen and then thawed.

CONCLUSION

The CFS obtained using this method may be used as a characteristic parameter for tissue characterization in noninvasive monitoring the transition zone between frozen and unfrozen tissues during the surgical therapy, and evaluating postoperative effects.

Photon-Induced Weyl Half-Metal Phase and Spin Filter Effect from Topological Dirac Semimetals

Recently discovered Dirac semimetals (DSMs) with two Dirac nodes, such as Na_{3}Bi and Cd_{2}As_{3}, are regarded as carrying the Z_{2} topological charge in addition to the chiral charge. We study the Floquet phase transition of Z_{2} topological DSMs subjected to a beam of circularly polarized light. Owing to the resulting interplay of the chiral and Z_{2} charges, the Weyl nodes are not only chirality dependent but also spin dependent, which constrains the behavior in creation and annihilation of the pair of Weyl nodes. Interestingly, we find a novel phase: One spin band is in the Weyl semimetal phase while the other is in the insulator phase, and we dub it the Weyl half-metal (WHM) phase. We further study the spin-dependent transport in a Dirac-Weyl semimetal junction and find a spin filter effect as a fingerprint of the existence of the WHM phase. The proposed spin filter effect, based on the WHM bulk band, is highly tunable in a broad parameter regime and robust against magnetic disorder, which is expected to overcome the shortcomings of the previously proposed spin filter based on the topological edge or surface states. Our results offer a unique opportunity to explore the potential applications of topological DSMs in spintronics.

MicroRNA-378 acts as a prognosis marker and inhibits cell migration, invasion and epithelial-mesenchymal transition in human glioma by targeting IRG1

OBJECTIVE

Glioma is one common intracranial malignancy. Recently, there has been a large volume of published studies describing the functions of microRNAs as potential diagnostic markers for glioma. Data from several sources revealed that miR-378 played crucial roles in multiple tumors. However, much uncertainty still exists about the functions and underlying mechanism of miR-378. The purpose of the present work was to evaluate the potential effect of miR-378 and verify its influence on the function of IRG1 in glioma.

PATIENTS AND METHODS

The miR-378 expression was examined in 52 pairs of glioma tissues using quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). Transwell assays were conducted to detect the capability of glioma cell migration and invasion with different transfections. Luciferase reporter was used to confirm whether miR-378 could regulate immune responsive gene 1 (IRG1). Western blot was used to measure the expressions of EMT-related markers.

RESULTS

miR 378 expressions were notably reduced in glioma cells and tissues in comparison with controls. The declined miR-378 expressions were correlated with the poor OS and worse clinicopathological parameters of glioma patients. Overexpression of miR-378 repressed glioma cell epithelial-mesenchymal transition (EMT) and metastasis as well as the tumor growth rate and tumor size of glioma mice. Additionally, IRG1 was markedly up-regulated in glioma and was confirmed as a direct target for miR 378 in glioma.

CONCLUSIONS

We showed that the suppressive role of miR-378 in glioma, which was regulated by IRG1, suggested that the miR-378/IRG1 axis may be an effective target for glioma treatment.

[High level of hemoglobin during the first trimester of pregnancy associated with the risk of gestational diabetes mellitus]

Objective: To explore the relationship between hemoglobin (Hb) level during the first trimester of pregnancy and gestational diabetes mellitus (GDM). Methods: A total of 1 276 participants, who underwent scheduled prenatal examination and normal singleton delivery at the Fifth People's Hospital of Shanghai and Hospital of Intergrated Chinese and Western Medicine in Minhang District, from January 2016 to May 2018 were included. There were 99 cases of GDM (GDM group) and 1 177 cases of normal (control group) pregnant women.Based on the serum Hb level during the first trimester of pregnancy, participants were divided into three groups, 236 cases of low Hb level group (Hb<110 g/L), 868 cases of normal Hb level group (110 g/L≤Hb<130 g/L), and 172 cases of high Hb level group (Hb≥130 g/L). Maternal clinical data were collected, including Hb level during the first trimester of pregnancy, three-point blood glucose (BG) of oral glucose tolerance test (OGTT) and fasting insulin during the second trimester of pregnancy. Homeostasis model assessment of insulin resistance index (HOMA-IR) and homeostasis model assessment of pancreatic β cell function index (HOMA-β) were used to evaluate insulin resistance and pancreatic β cell function. Results: (1) Hb level during the first trimester of pregnancy in GDM group was significantly higher than that in control group [(123±10),(119±11) g/L, P<0.05]. There were no significant difference in gravidity, parity, index of liver and renal function (all P>0.05). (2) Pre-pregnancy body mass index (BMI), 1-hour BG and 2-hour BG of OGTT were significantly increased in the high Hb level group during the first trimester of pregnancy, which were (23±4) kg/m(2), (7.3±2.0) mmol/L, and (6.5±1.4) mmol/L (P<0.05), respectively. The pre-pregnancy BMI, 1-hour BG and 2-hour BG of the normal or low Hb level group were (22±3) kg/m(2), (6.7±1.6) mmol/L, (6.1±1.2) mmol/L; (22±3) kg/m(2), (6.5±1.5) mmol/L, (5.9±1.1) mmol/L, respectively. There were no statistically significant difference in levels of fasting blood glucose, fasting insulin, HOMA-IR and HOMA-β within 3 groups (all P>0.05). (3) In the high Hb level group, prevalence of pregnancy overweight or obesity and GDM were the highest, which were 37.2%(64/172) and 15.1%(26/172), respectively; the differences were statistically significant (all P<0.05). (4) The serum Hb level in the first trimester was positively related with pre-pregnancy BMI (r=0.130, P<0.05), 1-hour BG (r=0.129, P<0.05), 2-hour BG (r=0.134, P<0.05), fasting insulin (r=0.096, P<0.05), and HOMA-IR (r=0.101, P<0.05).Logistic regression indicated that Hb≥130 g/L during the first trimester of pregnancy was an independent risk factor for GDM (OR=2.799, 95%CI: 1.186-6.604; P<0.05). Conclusion: The high level of Hb (Hb≥130 g/L) during the first trimester of pregnancy is associated with GDM.

Topological valley pumping in Weyl semimetals

We investigate the topological pumping effect in Weyl semimetals, subject to the modulation of two ac electric fields along y  and z directions, respectively. We show that the pumping effect originates from the anomalous velocity related to the Berry curvature. The direction of the pumping current is dependent on the chirality of the Weyl fermions. While the total particle current is vanishing because the Weyl points of opposite chirality always come in pairs in Weyl semimetals, the pump gives rise to a net chirality current or valley current. The noiseless valley current generated can be useful in valleytronic applications.

Quantum Oscillations of the Positive Longitudinal Magnetoconductivity: A Fingerprint for Identifying Weyl Semimetals

Weyl semimetals (WSMs) host charged Weyl fermions as emergent quasiparticles. We develop a unified analytical theory for the anomalous positive longitudinal magnetoconductivity (LMC) in a WSM, which bridges the gap between the classical and ultraquantum approaches. More interestingly, the LMC is found to exhibit periodic-in-1/B quantum oscillations, originating from the oscillations of the nonequilibrium chiral chemical potential. The quantum oscillations, superposed on the positive LMC, are a remarkable fingerprint of a WSM phase with a chiral anomaly, whose observation is a valid criteria for identifying a WSM material. In fact, such quantum oscillations were already observed by several experiments.

Texture Feature Differences between Fresh and Frozen-thawed Ex-vivo Porcine Liver Tissue in B-mode Ultrasonic Imaging

BACKGROUND

Ultrasound guidance of cryotherapy could be improved if changes of tissue characterization parameters during freezing could be used to monitor freezing profiles and estimate frostbite distributions.

OBJECTIVE

To investigate if B-mode ultrasonic imaging can provide sufficient information to define the damaged zone during cryotherapy by quantifying the differences of texture features between fresh and frozen-thawed porcine liver tissue.

MATERIALS AND METHODS

The B-mode ultrasonic images were obtained from ten porcine liver tissue samples before and after frozen-thawing treatment, then 20 texture parameters of the grey level histogram (GLH) and the grey level co-occurrence matrix (GLCM) from each image were extracted and analyzed statistically.

RESULTS

It was found that the differences in two texture parameters between the fresh and frozen-thawed tissue are significant enough for diagnostic purpose (variance: 317.0%, contrast: 144.4%).

CONCLUSION

Texture feature analysis of B-mode ultrasonic images can effectively differentiate the fresh and frozen-thawed porcine liver tissues, which offers a prospect for the future practice of evaluating the effectiveness of cryotherapy using Ultrasound.

Clinical management and prevention of dental caries in athletes: A four-year randomized controlled clinical trial

The aims of this four-year randomized controlled clinical trial were to gain insights into management and prevention of dental caries and the effect of stannous fluoride products in athletes. Fifty-four participants were randomized into test and control groups. The test group used special stannous fluoride products. The primary endpoint dental caries was assessed by the ICDAS-II-System and analyzed both by a linear mixed model for repeated measures and a generalized linear mixed model. During the observation period an increase in caries-free surfaces from 64.91 ± 6.42 at baseline to 73.22 ± 4.43 was observed. In surfaces with caries superficialis and caries media, a decrease from 13.94 ± 5.70 and 2.96 ± 2.55 surfaces at baseline to 7.89 ± 3.18 and 0.46 ± 0.78 after 2.5 years was noted, respectively. The analysis showed no effect of stannous fluoride products, but a significant difference for the time of examination (p < 0.0001). In addition, it could be shown that at any time of examination, the odds of developing caries media on a new surface was significantly lower than at baseline (up to 25-times). Due to biannual dental examinations, professional tooth cleaning and restorative treatment the number of caries-free surfaces increased and the odds of a new surface to be afflicted with caries media decreased 25-fold.

Time-reversal invariant resonant backscattering on a topological insulator surface driven by a time-periodic gate voltage

We study the scattering of the Dirac electrons by a point-like nonmagnetic impurity on the surface of a topological insulator, driven by a time-periodic gate voltage. It is found that, due to the doublet degenerate crossing points of different Floquet sidebands, resonant backscattering can happen for the surface electrons, even without breaking the time-reversal (TR) symmetry of the topological surface states (TSSs). The energy spectrum is reshuffled in a way quite different from that for the circularly polarized light, so that new features are exhibited in the Friedel oscillations of the local charge and spin density of states. Although the electron scattering is dramatically modified by the driving voltage, the 1/ρ scale law of the spin precession persists for the TSSs. The TR invariant backscattering provides a possible way to engineer the Dirac electronic spectrum of the TSSs, without destroying the unique property of spin-momentum interlocking of the TSSs.

Anti-hepatitis G E2 Antibody Detection and Its Relation to Serum HGV-RNA in Patients with Clotting Disorders: High Prevalence of HGV Infection and Spontaneous Remission

In a previous study, we have determined the prevalence of serum HGV-RNA in patients with congenital clotting disorders. Twenty-six (15%) of 175 patients investigated were serum HGV-RNA positive. In addition, HGV-RNA was detectable in peripheral blood mononuclear cells (PBMC) in ten percent of the cases, three of these patients were serum HGV-RNA negative.

In the present study, we have determined the prevalence of anti-HGV-E2 antibodies in the same patient population. Anti-HGV-E2 as determined by ELISA was detected in 45 patients (25.7%). Forty of these patients were serum HGV-RNA negative.

Ninety-two percent of the 26 HGV viremic patients and all but one patient (44 patients) with detectable anti-HGV-E2 had coinfection with the hepatitis C virus (HCV). Of these coinfected patients, 62.5% of HGV viremic patients and 53% of anti-HGV-E2 positive patients showed elevated serum ALT levels. Anti-HGV-E2 seroconversion is thus not associated with HCV infection. Two patients who were solely infected with HGV had normal serum ALT levels. In a retrospective longitudinal study, we have observed in 15 patients that serum HGV-RNA persisted during one to 19 years of follow-up, while anti-HGV-E2 was repeatedly negative. Five additional patients who were anti-HGV-E2 positive with concomitant detectable HGV-RNA (4 patients in serum and 1 patient in PBMC) became HGV-RNA negative during follow-up, ranging from 1 to 8 years after the first detection of anti-HGV-E2 antibodies. Two patients had lost anti-HGV-E2 antibodies 3 to 6 years after the seroconversion without the re-appearance of serum HGV-RNA. From these findings, it is clear that the prevalence rate of HGV infection in patients with clotting disorders as determined by PCR assay for HGV-RNA and anti-HGV-E2 by ELISA is actually higher than the prevalence of HGV viremia. Although HGV viremia may persist for longer than 19 years, most of the patients infected with HGV may clear the viremia spontaneously. The clearance of viremia is usually associated with seroconversion to anti-HGVE2. In addition, anti-HGV-E2 may be lost during years of follow-up without the reappearance of the HGV-RNA. Although HGV infection does not seem to influence the fate of HCV infection and does not induce increased levels of serum ALT, the clinical significance of long-term infection remains to be established.

Analytical theory and possible detection of the ac quantum spin Hall effect

We develop an analytical theory of the low-frequency ac quantum spin Hall (QSH) effect based upon the scattering matrix formalism. It is shown that the ac QSH effect can be interpreted as a bulk quantum pumping effect. When the electron spin is conserved, the integer-quantized ac spin Hall conductivity can be linked to the winding numbers of the reflection matrices in the electrodes, which also equal to the bulk spin Chern numbers of the QSH material. Furthermore, a possible experimental scheme by using ferromagnetic metals as electrodes is proposed to detect the topological ac spin current by electrical means.

Theory of Inverse Edelstein Effect of The Surface States of A Topological Insulator

The surface states of three-dimensional topological insulators possess the unique property of spin-momentum interlocking. This property gives rise to the interesting inverse Edelstein effect (IEE), in which an applied spin bias μ is converted to a measurable charge voltage difference V. We develop a semiclassical theory for the IEE of the surface states of Bi2Se3 thin films, which is applicable from the ballistic regime to diffusive regime. We find that the efficiency of the spin-charge conversion, defined as γ = V/μ, exhibits a universal dependence on the ratio between sample size and electron mean free path. The efficiency increases from γ = π/4 in the ballistic limit to γ = π in the diffusive limit, suggesting that sufficient strength of impurity scattering is favorable for the IEE.

The further exploration of hidden blood loss in posterior lumbar fusion surgery

PURPOSE

Hidden blood loss (HBL) plays an important role in lumbar fusion surgery. However, there was huge computation error when calculating hidden loss in previous studies because they regarded the volume of drainage as postoperative blood loss. We should not ignore the fact that the composition of drainage varies from person to person and also with time-lapse after operation. The purpose of this study was to demonstrate a more accurate HBL calculation formula by comparing it with previous formula and to address the importance of HBL in patients undergoing posterior lumbar fusion surgeries.

METHODS

For each patient, the HBL was calculated by previous formula and our recommendable formula. We compared the result of HBL calculated by two different methods. At the same time, we explored the HBL in patients undergoing posterior lumbar fusion surgeries with various levels.

RESULTS

In our study, the average total blood loss was 771ml. The mean intraoperative blood loss was 268ml, and the total volume of post-operative drainage is 276ml. The mean hidden loss of 90 patients calculated with previous method was 227ml and 29.4% of total loss. When taking change of drainage HCT into account, the mean hidden loss calculated with our recommendable method was 362.8ml and 47% of total loss. The results were significantly different (P<0.01). There was no significant difference in the percentage of the HBL between patients with single or multiple surgical levels.

CONCLUSIONS

There is often a substantial unmeasured blood loss in lumbar fusion surgeries. However, the component of drainage changed radically with time, we should take the true blood contained in drainage into considerations when calculating the HBL.

LEVEL OF EVIDENCE

Our research is a case-control study and the level of proof is III.

Mutant p53 upregulates alpha-1 antitrypsin expression and promotes invasion in lung cancer

Missense mutations in the TP53 tumor-suppressor gene inactivate its antitumorigenic properties and endow the incipient cells with newly acquired oncogenic properties that drive invasion and metastasis. Although the oncogenic effect of mutant p53 transcriptome has been widely acknowledged, the global influence of mutant p53 on cancer cell proteome remains to be fully elucidated. Here, we show that mutant p53 drives the release of invasive extracellular factors (the 'secretome') that facilitates the invasion of lung cancer cell lines. Proteomic characterization of the secretome from mutant p53-inducible H1299 human non-small cell lung cancer cell line discovered that the mutant p53 drives its oncogenic pathways through modulating the gene expression of numerous targets that are subsequently secreted from the cells. Of these genes, alpha-1 antitrypsin (A1AT) was identified as a critical effector of mutant p53 that drives invasion in vitro and in vivo, together with induction of epithelial-mesenchymal transition markers expression. Mutant p53 upregulated A1AT transcriptionally through the involvement with its family member p63. Conditioned medium containing secreted A1AT enhanced cell invasion, while an A1AT-blocking antibody attenuated the mutant p53-driven migration and invasion. Importantly, high A1AT expression correlated with increased tumor stage, elevated p53 staining and shorter overall survival in lung adenocarcinoma patients. Collectively, these findings suggest that A1AT is an indispensable target of mutant p53 with prognostic and therapeutic potential in mutant p53-expressing tumors.

Experimental Observation of Anisotropic Adler-Bell-Jackiw Anomaly in Type-II Weyl Semimetal WTe_{1.98} Crystals at the Quasiclassical Regime

The asymmetric electron dispersion in type-II Weyl semimetal theoretically hosts anisotropic transport properties. Here, we observe the significant anisotropic Adler-Bell-Jackiw (ABJ) anomaly in the Fermi-level delicately adjusted WTe_{1.98} crystals. Quantitatively, C_{W}, a coefficient representing the intensity of the ABJ anomaly along the a and b axis of WTe_{1.98} are 0.030 and 0.051  T^{-2} at 2 K, respectively. We found that the temperature-sensitive ABJ anomaly is attributed to a topological phase transition from a type-II Weyl semimetal to a trivial semimetal, which is verified by a first-principles calculation using experimentally determined lattice parameters at different temperatures. Theoretical electrical transport study reveals that the observation of an anisotropic ABJ along both the a and b axes in WTe_{1.98} is attributed to electrical transport in the quasiclassical regime. Our work may suggest that electron-doped WTe_{2} is an ideal playground to explore the novel properties in type-II Weyl semimetals.

Investigation of an InP-based image converter with optical excitation

An image converter based on an indium phosphide has been developed to measure the two-dimensional spatial profile of the incident photon flux by probing the rapid change of the refractive index in the semiconductor. The spatial resolution, dynamic range, and temporal response of this image converter have been investigated with optical methods. The results show that the spatial resolution is ∼15 cycles/mm at the percent modulation transfer function of 0.5, the dynamic range is about 100, and the time response is in the order of 600 ps. This scheme can provide an alternative choice as an imaging diagnostic for experiments in the area of high-energy density physics.

The risk predictive values of UK-PBC and GLOBE scoring system in Chinese patients with primary biliary cholangitis: the additional effect of anti-gp210

BACKGROUND

Adequate risk stratification is critical for the management of the patients with primary biliary cholangitis (PBC). The UK-PBC and GLOBE scoring systems for prognosis of PBC have been proposed recently, but have not been validated in Asian population.

AIM

To validate the UK-PBC and GLOBE scoring systems in Chinese patients for prognosis of PBC. To clarify the role of anti-gp210 as a biomarker, and to investigate whether anti-gp210 could affect the prognostic values of UK-PBC and GLOBE scoring systems.

METHODS

We retrospectively analysed 276 patients with PBC evaluated between September 2004 and May 2016, including 133 anti-gp210+ and 143 anti-gp210- patients.

RESULTS

The 5-year adverse outcome-free survivals of anti-gp210+ vs. anti-gp210- patients were 70% and 85%, respectively (P = 0.005). Cirrhosis (P = 0.001), albumin level ≤40 g/L (P = 0.011) and platelet count ≤153 × 10⁹ (P < 0.001) had a superimposition effect on anti-gp210 antibody as a risk factor. Furthermore, long-term prognoses were evaluated using the UK-PBC and GLOBE scores. For UK-PBC scoring system, the area under receiver operating characteristic curve (AUROC) was 0.924 for all patients with PBC (n = 223), 0.940 for anti-gp210+ patients (n = 110) and 0.888 for anti-gp210- patients (n = 113). For GLOBE scoring system, the area under receiver operating characteristic curve was 0.901 for all patients with PBC (n = 223), 0.924 for anti-gp210+ patients (n = 110) and 0.848 for anti-gp210- patients (n = 113). UK-PBC score >0.0578 (P < 0.001, HR: 32.736, 95% CI: 11.368-94.267) and GLOBE score <0.850 (P < 0.001, HR: 18.763, 95% CI: 7.968-44.180) were associated with poorer outcomes in the whole cohort.

CONCLUSIONS

The UK-PBC and GLOBE scoring systems were good 5-year prognostic predictors in Chinese patients with PBC, especially in anti-gp210+ patients. As a biomarker, anti-gp210 antibody was associated with a more severe cholestatic manifestation and a worse long-term prognosis. The anti-gp210 antibody could be added to further optimise the UK-PBC and GLOBE scoring systems.

Time-reversal-breaking induced quantum spin Hall effect

We show that quantum spin Hall (QSH) effect does not occur in a square lattice model due to cancellation of the intrinsic spin-orbit coupling coming from different hopping paths. However, we show that QSH effect can be induced by the presence of staggered magnetic fluxes alternating directions square by square. When the resulting Peierls phase takes a special value , the system has a composite symmetry ΘΡ₋ with Θ the time-reversal operator and Ρ₋ transforming the Peierls phase from γ to γ − , which protects the gapless edge states. Once the phase deviates from , the edge states open a gap, as the composite symmetry is broken. We further investigate the effect of a Zeeman field on the QSH state, and find that the edge states remain gapless for . This indicates that the QSH effect is immune to the magnetic perturbation.

Abstract P4-05-02: Conditional inactivation of the 25-hydroxyvitamin D-24-hydroxylase (Cyp24a1) in the mouse mammary epithelium alters mammary gland development

The biologically active form of vitamin D (1,25(OH)2D) regulates proliferation, differentiation, and apoptosis in diverse cell types. We have previously identified anti-proliferative activities of 1,25(OH)2D in human breast tissue, as well as 1,25(OH)2D target gene expression consistent with reports that elevated vitamin D levels may protect against cancer. In mouse studies, vitamin D signaling modulates normal mammary gland development, including ductal outgrowth and branching, and protects against tumorigenesis. Degradation of 1,25(OH)2D is initiated by the enzyme Cyp24a1 in target tissues, providing critical local control of 1,25(OH)2D bioactivity. In vitro, blockade of Cyp24a1 activity potentiates the anti-proliferative effects of 1,25(OH)2D. However, the extent to which endogenous Cyp24a1 activity within the mammary epithelium regulates local 1,25(OH)2D levels to modulate normal mammary gland development, with possible implications for cancer, has not been investigated. We generated a novel mouse model with conditional knockout of the Cyp24a1 gene specifically in the mammary epithelium (MMTV-Cre x Cyp24a1lox/lox). Ablation of Cyp24a1 activity in the mammary epithelium does not alter either gland or body weight at 4, 6 or 10 weeks of age. Preliminary analyses of mammary gland whole mounts indicate that virgin knockout mice form fewer terminal end buds compared to glands from wild-type littermates at 4 and 6 weeks of age (P&lt;0.05). Moreover, the width of the ducts proximal to the central lymph node of knockout mice was less than that of wild-type mice at 4 and 10 weeks of age (P&lt;0.05 and P&lt;0.01, respectively). In addition, the number of secondary and tertiary branching points is reduced in mammary glands from knockout mice at 6 weeks of age (P&lt;0.05 and P&lt;0.01, respectively). In summary, our findings suggest that Cyp24a1 activity within epithelial cells plays a crucial role to modulate postnatal mammary gland development, presumably by limiting the local accumulation of 1,25(OH)2D.

Topological phases of the kicked Harper-Kitaev model with ultracold atoms

We propose using ultracold atoms trapped in a one-dimensional periodically driven optical lattice to realize the Harper-Kitaev model, where the on-site energies are periodically kicked. Such a system provides a natural platform to study both Chern insulators and Majorana fermions. Based on calculating the quasienergy spectra, we find that both Floquet Majorana modes and Hall chiral edge modes could appear at the sample boundary in the gaps between the quasienergy bands. We also study the competition of topological superconductor and Chern insulator states in the model. We calculate the [Formula: see text] index and Floquet Chern number to characterize the above two different topological states, including the topological phase transitions in the kicked Harper-Kitaev model with the increase in the strength of the kick.

π Spin Berry Phase in a Quantum-Spin-Hall-Insulator-Based Interferometer: Evidence for the Helical Spin Texture of the Edge States

The quantum spin Hall insulator is characterized by helical edge states, with the spin polarization of the electron being locked to its direction of motion. Although the edge-state conduction has been observed, unambiguous evidence of the helical spin texture is still lacking. Here, we investigate the coherent edge-state transport in an interference loop pinched by two point contacts. Because of the helical character, the forward interedge scattering enforces a π spin rotation. Two successive processes can only produce a nontrivial 2π or trivial 0 spin rotation, which can be controlled by the Rashba spin-orbit coupling. The nontrivial spin rotation results in a geometric π Berry phase, which can be detected by a π phase shift of the conductance oscillation relative to the trivial case. Our results provide smoking gun evidence for the helical spin texture of the edge states. Moreover, it also provides the opportunity to all electrically explore the trajectory-dependent spin Berry phase in condensed matter.

Topological spin and valley pumping in silicene

We propose to realize adiabatic topological spin and valley pumping by using silicene, subject to the modulation of an in-plane ac electric field with amplitude Ey and a vertical electric field consisting of an electrostatic component and an ac component with amplitudes and . By tuning and , topological valley pumping or spin-valley pumping can be achieved. The low-noise valley and spin currents generated can be useful in valleytronic and spintronic applications. Our work also demonstrates that bulk topological spin or valley pumping is a general characteristic effect of two-dimensional topological insulators, irrelevant to the edge state physics.