Regenerative braking system effectively reduces the formation of brake wear particles

Brake wear particles (BWPs) are considered one of the most significant non-exhaust particle emission sources from motor vehicles. Previous studies have primarily focused on BWPs from conventional fuel vehicles (CFVs), with limited research available on BWPs from new energy vehicles (NEVs). We developed an independent BWP emission testing system applicable to NEVs and conducted BWP emission tests on representative NEVs and CFVs under various testing cycles via a chassis dynamometer. The BWP emission characteristics of the NEVs equipped with regenerative braking system significantly differed from those of gasoline vehicles. For transient emission characteristics, gasoline vehicles exhibited higher peak concentrations during brake events than brake drag events, while those with regenerative braking exhibited the opposite feature. Under continuous braking, the concentration of ultrafine particles emitted by NEVs was reduced by more than 3 orders of magnitude compared to gasoline vehicles. In terms of single-particle morphology, BWPs could be mainly divided into three categories: carbonaceous particles, iron-rich particles, and mixed metal particles. We obtained realistic emission characteristics of BWPs from NEVs, which could provide data support and a scientific basis for the formulation of relevant emission standards and control measures in the future.

Transforming waste brake pads from automobiles into Nano-Catalyst: Synergistic Fe-C-Cu triple sites for efficient fenton-like oxidation of organic pollutants

The arbitrary disposal of used brake pads from motor vehicles has resulted in severe heavy metal pollution and resource wastage, highlighting the urgent need to explore the significant untapped potential of these discarded materials. In this study, The in-situ growth of highly dispersed Fe2O3 nanocrystals was achieved by simple oxidation annealing of brake pad debris(BPD). Interestingly, Cu remained unoxidized and acted as a "valence state transformation bridge of Fe2O3" to construct the "triple Fe-C-Cu sites". The Fenton degradation experiment of pollutants was conducted under constant temperature conditions at 40 °C, a stirring rate of 1300 rpm, a pH value of 3, a catalyst dosage of 0.5 g/L, pollutant dosage ranging from 50 to 400 mg/L, and H2O2 dosage of 0.25 g/L. Experimental results showed that BPD treated at 300 °C for 2 h exhibited optimal Fenton-like oxidation activity, achieving rapid degradation of over 90 % of refractory antibiotics, such as tetracycline and ciprofloxacin, in organic wastewater within 10 min. This remarkable performance was mainly attributed to the synergistic effect of "Fe-C-Cu triple sites", where the electron-donating role of C in the Fe-C and Cu-C interfaces facilitated the conversion of the Fe(III) to Fe(II) and Cu(II) to Cu(I). In addition, the ability of Cu2+ to accept electrons at the Fe-Cu interface promoted the transition from Fe (II) to Fe (III). This "balance of electron gain and loss" accelerated the interfacial electron transfer and the recycle of dual Fenton sites, Fe(II)/Fe(III) and Cu(I)/Cu(II), to generate more ·OH from H2O2. Therefore, this strategy of functionalizing BPD as Fenton-like catalysts without the addition of external Fe provides intriguing prospects for understanding the construction of Fe-based Fenton catalysts and resource utilization of Fe-containing solid waste materials.

[Research on epidemiological characteristics of pneumonia and correlative factors of length of hospitalization in the elderly aged 60 years and older in Ningbo]

Objective: To investigate the epidemiological characteristics of pneumonia and the related factors of the length of hospitalization of pneumonia in the elderly aged 60 years and older in Ningbo in 2019. Methods: Data on hospitalized cases of pneumonia in the elderly aged 60 years and older in Ningbo in 2019 were collected through the regional health information platform, and the population data of Ningbo in 2019 were obtained through the Zhejiang Provincial Bureau of Statistics. A descriptive epidemiological analysis was conducted on hospitalized cases of pneumonia in the elderly population, and factors related to the length of hospitalization were explored. Results: A total of 15 956 hospitalized cases of pneumonia aged 60 years and older were reported in Ningbo in 2019, and the incidence of pneumonia requiring hospitalization was 1.02% (15 956/1 571 431). The incidence was 1.13% (8 613/760 357) in males and 0.83% (6 759/811 074) in females, and the ratio of male to female cases was 1.27∶1. The highest incidence was found in the ≥80 age group (2.52%), and the lowest incidence was found in the 60-69 age group (0.58%). March, February, and January were the peak period of pneumonia hospitalization. The main types of pneumonia diagnosed were not specified (65.12%), followed by bacterial pneumonia (34.60%). The M(Q1, Q3) of hospitalized patients with pneumonia was 9 (7, 13) days. The results of multivariate logistic regression analysis showed that gender (female: OR=0.911, 95%CI: 0.849-0.978) and older age (70-79 years old: OR=1.211, 95%CI: 1.111-1.321; ≥80 years old group: OR=1.486, 95%CI: 1.365-1.617), settlement method (self-payment: OR=0.567, 95%CI: 0.464-0.691), higher level of hospitals (Grade Ⅱ: OR=1.902,95%CI:1.723-2.100; Grade Ⅲ: OR=1.546,95%CI:1.407-1.698) were associated with the length of hospitalization for pneumonia in people aged 60 years and older in Ningbo. Conclusions: Hospitalization with pneumonia in people aged 60 years and older was high in winter and spring, men and older adults were in high-risk groups in Ningbo in 2019. Gender, age, billing method, and level of hospitals may be related factors to the length of hospitalization for pneumonia.

Effects of heat waves and cold spells on blood parameters: a cohort study of blood donors in Tianjin, China

BACKGROUND

With the increasing occurrence of extreme temperature events due to climate change, the attention has been predominantly focused on the effects of heat waves and cold spells on morbidity and mortality. However, the influence of these temperature extremes on blood parameters has been overlooked.

METHODS

We conducted a cohort study involving 2,752 adult blood donors in Tianjin, China, between January 18, 2013, and June 25, 2021. The generalized additive mixed model was used to investigate the effects and lagged effects of heat waves and cold spells on six blood parameters of blood donors, including alanine aminotransferase (ALT), white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HB), hematocrit (HCT), and platelet count (PLT). Subgroup analyses were stratified by sex, age, and BMI.

RESULTS

Heat waves and cold spells are associated with changes in blood parameters, particularly HB and PLT. Heat waves increased HB and PLT, while cold spells increased HB and decreased PLT. The effect of heat waves is greater than that of cold spells. The largest effect of heat waves on HB and PLT occurred at lag1 with 2.6 g/L (95% CI: 1.76 to 3.45) and lag7 with 9.71 × 10^9/L (95% CI: 6.26 to 13.17), respectively, while the largest effect of cold spells on HB and PLT occurred at lag0 with 1.02 g/L (95% CI: 0.71 to 1.33) and lag2 with -3.85 × 10^9/L (95% CI: -5.00 to -2.70), respectively. In subgroup analysis, the effect of cold spells on ALT was greater in the 40-49 age group.

CONCLUSION

We indicated that heat waves and cold spells can impact hemoglobin and platelet counts in the human body. These findings provide evidence linking heat waves or cold spells to diseases and may reduce health risks caused by extreme temperature events.

Direct measurement of brake and tire wear particles based on real-world driving conditions

With implementing vehicle emission control policies, tailpipe particulate emissions have been gradually controlled, and the relative contribution of non-tailpipe particulate emissions, such as brake and tire wear, has further increased. A unified and scientific method for sampling non-tailpipe particulate matter (PM) emissions is essential to improve the accuracy of the emission characteristics and factors. This study proposes a novel sampling method based on real-world driving conditions to obtain information on emissions and extract characteristic conditions for tire and brake pad wear. We extracted 200 representative braking segments for simulation experiments based on road type, initial and final velocities, temperature, and deceleration rate. Two standard test cycles to simulate the tire wear conditions of the front and rear wheels were constructed based on velocity, lateral, and vertical forces. Under the real-world driving condition test cycle, the emission factors of PM2.5 and PM10 for brake wear particles of passenger vehicles were 2.66 mg/km and 11.65 mg/km, respectively. In contrast, the emission factors of PM2.5 and PM10 for tire wear particles were 0.21 mg/km and 1.27 mg/km, respectively. Moreover, this study provides insights and basic data for localizing and improving the emission model, which can enhance its applicability and accuracy.

[Epidemiological characteristics and spatiotemporal distribution of schizophrenia in Ningbo, 2018-2022]

Objective: To explore the temporal and spatial distribution characteristics of reported incidence of schizophrenia in Ningbo from 2018 to 2022 and to provide a scientific basis for rational allocation of mental health resources and comprehensive prevention and treatment of schizophrenia. Methods: The reported incidence data of schizophrenia from 2018 to 2022 were collected from Ningbo's mental health information management system, and the reported incidence was calculated by township. The spatial correlation analysis and the spatiotemporal scan analysis were used to study the spatiotemporal distribution of schizophrenia. Results: The reported incidence of schizophrenia decreased from 2018 to 2022, with 4 133 new cases reported, and the annual average reported incidence was 9.76/100 000. Global and local spatial autocorrelation analysis showed positive spatial correlations and hot spots in 2018-2020. The space-time scan analysis showed an incidence cluster in Dongqiao Town, Haishu District, during 2018-2019. The RR was 2.46, and the log-likelihood ratio was 256.89. Conclusions: The reported incidence of schizophrenia in Ningbo has obvious temporal and spatial aggregation, and the high incidence area explored can provide clues for further research on the correlation between environmental factors and the incidence of schizophrenia and has certain guiding significance for the rational allocation of mental health resources in Ningbo.

Chemical and Cellular Formation of Reactive Oxygen Species from Secondary Organic Aerosols in Epithelial Lining Fluid

INTRODUCTION

Oxidative stress mediated by reactive oxygen species (ROS) is a key process for adverse aerosol health effects. Secondary organic aerosols (SOA) account for a major fraction of particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5). PM2.5 inhalation and deposition into the respiratory tract causes the formation of ROS by chemical reactions and phagocytosis of macrophages in the epithelial lining fluid (ELF), but their relative contributions are not well quantified and their link to oxidative stress remains uncertain. The specific aims of this project were (1) elucidating the chemical mechanism and quantifying the formation kinetics of ROS in the ELF by SOA; (2) quantifying the relative importance of ROS formation by chemical reactions and macrophages in the ELF.

METHODS

SOA particles were generated using reaction chambers from oxidation of various precursors including isoprene, terpenes, and aromatic compounds with or without nitrogen oxides (NOx). We collected size-segregated PM at two highway sites in Anaheim, CA, and Long Beach, CA, and at an urban site in Irvine, CA, during two wildfire events. The collected particles were extracted into water or surrogate ELF that contained lung antioxidants. ROS generation was quantified using electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique. PM oxidative potential (OP) was also quantified using the dithiothreitol assay. In addition, kinetic modeling was applied for analysis and interpretation of experimental data. Finally, we quantified cellular superoxide release by RAW264.7 macrophage cells upon exposure to quinones and isoprene SOA using a chemiluminescence assay as calibrated with an EPR spin-probing technique. We also applied cellular imaging techniques to study the cellular mechanism of superoxide release and oxidative damage on cell membranes.

RESULTS

Superoxide radicals (·O2-) were formed from aqueous reactions of biogenic SOA generated by hydroxy radical (·OH) photooxidation of isoprene, β-pinene, α-terpineol, and d-limonene. The temporal evolution of ·OH and ·O2- formation was elucidated by kinetic modeling with a cascade of aqueous reactions, including the decomposition of organic hydroperoxides (ROOH), ·OH oxidation of primary or secondary alcohols, and unimolecular decomposition of α-hydroxyperoxyl radicals. Relative yields of various types of ROS reflected the relative abundance of ROOH and alcohols contained in SOA, which generated under high NOx conditions, exhibited lower ROS yields. ROS formation by SOA was also affected by pH. Isoprene SOA had higher ·OH and organic radical yields at neutral than at acidic pH. At low pH ·O2- was the dominant species generated by all types of SOA. At neutral pH, α-terpineol SOA exhibited a substantial yield of carbon-centered organic radicals (R·), while no radical formation was observed by aromatic SOA.

Organic radicals in the ELF were formed by mixtures of Fe2+ and SOA generated from photooxidation of isoprene, α-terpineol, and toluene. The molar yields of organic radicals by SOA were 5-10 times higher in ELF than in water. Fe2+ enhanced organic radical yields by a factor of 20-80. Ascorbate mediated redox cycling of iron ions and sustained organic peroxide decomposition, as supported by kinetic modeling reproducing time- and concentration-dependence of organic radical formation, as well as by additional experiments observing the formation of Fe2+ and ascorbate radicals in mixtures of ascorbate and Fe3+. ·OH and superoxide were found to be efficiently scavenged by antioxidants.

Wildfire PM mainly generated ·OH and R· with minor contributions from superoxide and oxygen-centered organic radicals (RO·). PM OP was high in wildfire PM, exhibiting very weak correlation with radical forms of ROS. These results were in stark contrast with PM collected at highway and urban sites, which generated much higher amounts of radicals dominated by ·OH radicals that correlated well with OP. By combining field measurements of size-segregated chemical composition, a human respiratory tract model, and kinetic modeling, we quantified production rates and concentrations of different types of ROS in different regions of the ELF by considering particle-size-dependent respiratory deposition. While hydrogen peroxide (H2O2) and ·O2- production were governed by Fe and Cu ions, ·OH radicals were mainly generated by organic compounds and Fenton-like reactions of metal ions. We obtained mixed results for correlations between PM OP and ROS formation, providing rationale and limitations of the use of oxidative potential as an indicator for PM toxicity in epidemiological and toxicological studies.

Quinones and isoprene SOA activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in macrophages, releasing massive amounts of superoxide via respiratory burst and overwhelming the superoxide formation by aqueous chemical reactions in the ELF. The threshold dose for macrophage activation was much smaller for quinones compared with isoprene SOA. The released ROS caused lipid peroxidation to increase cell membrane fluidity, inducing oxidative damage and stress. Further increases of doses led to the activation of antioxidant response elements, reducing the net cellular superoxide production. At very high doses and long exposure times, chemical production became comparably important or dominant if the escalation of oxidative stress led to cell death.

CONCLUSIONS

The mechanistic understandings and quantitative information on ROS generation by SOA particles provided a basis for further elucidation of adverse aerosol health effects and oxidative stress by PM2.5. For a comprehensive assessment of PM toxicity and health effects via oxidative stress, it is important to consider both chemical reactions and cellular processes for the formation of ROS in the ELF. Chemical composition of PM strongly influences ROS formation; further investigations are required to study ROS formation from various PM sources. Such research will provide critical information to environmental agencies and policymakers for the development of air quality policy and regulation.

Chemical characteristics of fine tire wear particles generated on a tire simulator

Tire wear is one of the major sources of traffic-related particle emissions, however, laboratory data on the components of tire wear particles (TWPs) is scarce. In this study, ten brands of tires, including two types and four-speed grades, were chosen for wear tests using a tire simulator in a closed chamber. The chemical components of PM2.5 were characterized in detail, including inorganic elements, water-soluble ions (WSIs), organic carbon (OC), elemental carbon (EC), and polycyclic aromatic hydrocarbons (PAHs). Inorganic elements, WSIs, OC, and EC accounted for 8.7 ± 2.1%, 3.1 ± 0.7%, 44.0 ± 0.9%, and 9.6 ± 2.3% of the mass of PM2.5, respectively. The OC/EC ratio ranged from 2.8 to 7.6. The inorganic elements were dominated by Si and Zn. The primary ions were SO42- and NO3-, and TWPs were proven to be acidic by applying an ionic balance. The total PAHs content was 113 ± 45.0 μg g-1, with pyrene being dominant. In addition, the relationship between the chemical components and tire parameters was analyzed. Inorganic elements and WSIs in TWPs were more abundant in all-season tires than those in winter tires, whereas the content of PAHs was the opposite. The mass fractions of OC, Si, and Al in the TWPs all showed increasing trends with increasing tire speed grade, but the PAHs levels showed a decreasing trend. Ultimately, to provide more data for further research, a TWPs source profile was constructed considering the tire weighting factor.

Heavy vehicles' non-exhaust exhibits competitive contribution to PM2.5 compared with exhaust in port and nearby areas

Heavy port transportation networks are increasingly considered as significant contributors of PM2.5 pollution compared to vessels in recent decades. In addition, evidence points to the non-exhaust emission of port traffic as the real driver. This study linked PM2.5 concentrations to varied locations and traffic fleet characteristics in port area through filter sampling. The coupled emission ratio-positive matrix factorisation (ER-PMF) method resolves source factors by avoiding direct overlap from collinear sources. In the port central and entrance areas, freight delivery activity emissions including vehicle exhaust and non-exhaust particles, as well as induced road dust resuspension, accounted for nearly half of the total contribution (42.5%-49.9%). In particular, the contribution of non-exhaust from denser traffic with high proportion of trucks was competitive and equivalent to 52.3% of that from exhaust. Backward trajectory statistical models further interpreted the notably larger-scale coverage of non-exhaust emissions in the port's central area. The distribution of PM2.5 were interpolated within the scope of the port and nearby urban areas, displaying the potential contribution of non-exhaust within 1.15 μg/m3-4.68 μg/m3, slightly higher than the urban detections reported nearby. This study may provide useful insights into the increasing percentage of non-exhaust from trucks in ports and nearby urban areas and facilitate supplementary data collection on Euro-VII type-approval limit settings.

Brake wear-derived particles: Single-particle mass spectral signatures and real-world emissions

Brake wear is an important but unregulated vehicle-related source of atmospheric particulate matter (PM). The single-particle spectral fingerprints of brake wear particles (BWPs) provide essential information for understanding their formation mechanism and atmospheric contributions. Herein, we obtained the single-particle mass spectra of BWPs by combining a brake dynamometer with an online single particle aerosol mass spectrometer and quantified real-world BWP emissions through a tunnel observation in Tianjin, China. The pure BWPs mainly include three distinct types of particles, namely, Ba-containing particles, mineral particles, and carbon-containing particles, accounting for 44.2%, 43.4%, and 10.3% of the total BWP number concentration, respectively. The diversified mass spectra indicate complex BWP formation pathways, such as mechanical, phase transition, and chemical processes. Notably, the mass spectra of Ba-containing particles are unique, which allows them to serve as an excellent indicator for estimating ambient BWP concentrations. By evaluating this indicator, we find that approximately 4.0% of the PM in the tunnel could be attributable to brake wear; the real-world fleet-average emission factor of 0.28 mg km^-1 veh^-1 is consistent with the estimation obtained using the receptor model. The results presented herein can be used to inform assessments of the environmental and health impacts of BWPs to formulate effective emissions control policies.

Determining factors and parameterization of brake wear particle emission

Brake wear emission contributes to an increasingly significant proportion of vehicle-related particulate matter, but knowledge of its emission features and determining factors is still highly insufficient. Here, brake dynamometer experiments were conducted under controlled variables tests and real-world driving conditions to systematically investigate brake wear particle (BWP) emission. Compared to the decelerating process, the separating of pads and disc releases more BWPs, accounting for 47-76% of the total PM_2.5 mass. Particle number and mass distributions exhibit bimodal (< 0.01 µm and 0.8-1.2 µm) and unimodal (2-5 µm) patterns, respectively. Larger speed reduction exponentially amplifies BWP emission, and the significant enhancement of nanoparticles is proved to be related to the evaporation of organic constituents in the pads with threshold ranging from 170 °C to 270 °C. Emissions from front and rear brake assemblies don't agree with braking torque distribution, mainly attributive to the different braking pressures. A parameterization scheme for BWP emission based on kinetic energy loss is further established and proved to sufficiently predict the variation of BWP under real-world driving conditions. Being corrected by 1.8th power of the initial speed, the scheme improves the prediction.

[Effectiveness of precise prevention and control strategies of dynamic zero COVID-19 in Ningbo, Zhejiang province]

Objective: To evaluate effectiveness of the precise prevention and control strategies of dynamic zero COVID-19 in Ningbo, Zhejiang province. Methods: Based on the incidence data of COVID-19 and case epidemiological survey report in Ningbo in December 2021, the incidence curve of COVID-19 was generated and a dynamics model was developed to estimate the case number of under different intervention measures. The basic reproduction number (R₀) and real-time reproduction number (R_t) were calculated to evaluate intervention effect. Results: A total of 74 cases of COVID-19 had been confirmed in Ningbo as of 17 December, 2021. The R₀ was estimated to be 4.3. With the strengthening of prevention and control measures, the R_t showed a gradual downward trend, dropping to below 1.0 on December 11 and 0.4 on December 14. The model fitting results showed that the actual case number was close to the estimated case number (76 cases) when the effectiveness of intervention was 90%. The number of cases decreased by 98.4% compared with that if no intervention was taken. Conclusion: The precise prevention and control strategies of dynamic zero COVID-19 have obvious effect, which can facilitate the rapid control of COVID-19 epidemic in Ningbo.

Research Progress on Pathological Fibrosis of Sinoatrial Node

Abstract

Human heart rhythm is mainly regulated and controlled by the sinoatrial node. Fibrosis plays an important regulating role in adjusting the structural and functional integrity of the sinoatrial node pacemaker complex. In physiological state, the fibrosis degree of sinoatrial node is negatively correlated with heart rate, positively correlated with age and heart size, and can maintain a relatively stable heart rate. Pathological fibrosis of sinoatrial node can induce various types of arrhythmias which can result in sudden death. Determination of the mechanisms related to sinoatrial node pathological fibrosis could provide a target for clinical treatment of sinoatrial node fibrosis and diagnosis basis for forensic pathologists. This paper reviews the main mechanism of sinoatrial node pathological fibrosis, including abnormal activation of cardiac fibroblast cells in sinoatrial node, hyperplasia of epicardial adipose tissue, calcium clock disorder, artery stenosis, etc., introduces the test methods, diagnostic criteria as well as its role in sudden cardiac death and discusses the potential application, to provide reference for relevant research and application.

[Seroepidemiology of pertussis in healthy population in Ningbo, 2019]

Objective: To understand the seroepidemiological characteristics of pertussis in healthy population in Ningbo, and estimate the overall incidence of pertussis. Methods: A cross-sectional survey method was used in this study. A total of 1 206 healthy residents in 9 age groups were stratified randomly selected from 3 counties of Ningbo. Serum samples were collected from the subjects, and the pertussis toxin immunoglobulin G antibody (PT-IgG) levels were measured quantitatively by enzyme-linked immunosorbent assay (ELISA). Results: The mean PT-IgG seropositive rate in the subjects was 0.91% (95%CI:0.45%-1.63%) with a geometric mean titer (GMT) of 3.10 (95%CI:2.86-3.36) IU/ml. The seropositive rates ranged from 0.00% to 1.68%, and the GMTs ranged from 2.08 IU/ml to 5.28 IU/ml in 9 age groups. The incidence rate of pertussis was estimated to be 4 572.81 per 100 000 in age group ≥5 years (95%CI:1 807.30 per 100 000-9 348.12 per 100 000), and the peak of estimated incidence rates were found in age group 5- years (9 301.62 per 100 000, 95%CI:1 121.77 per 100 000-33 154.68 per 100 000) and age group ≥50 years old (8 967.02 per 100 000, 95%CI: 1 059.45 per 100 000-31 845.94 per 100 000). Conclusions: The actual incidence of pertussis was high in Ningbo in 2019. As a result of waning immunity after vaccination, pertussis can occur in adolescents and adults. The pertussis surveillance should be strengthened and the pertussis vaccination strategy should be improved.

[Study on transmission dynamic of 15 clusters of COVID-2019 cases in Ningbo]

Objective: To describe the basic characteristics of clusters of coronavirus diseases 2019 (COVID-19) cases in Ningbo, Zhejiang province, and evaluate the generation time (Tg) and basic reproduction number (R(0)) of COVID-19. Methods: The basic information and onset times of the clusters of COVID-19 cases in Ningbo were investigated, the inter-generational interval of the cases were fitted by using gamma distribution, and the R(0) was calculated based on the SEIR model. Results: In the 15 clusters of COVID-19 cases, a total of 52 confirmed cases, 5 cases of nucleic acid-positive asymptomatic cases. The cases occurred from January 23 to February 4, the cases were mainly women. The incubation period was (6.11±3.38) days, and the median was 5 days. The Tg was (6.93±3.70) days. There were no significant differences in Tg between age group<60 years and age group 60 years and above, and between men and women (P=0.551). According to the Tg calculated in this paper, the R(0) of COVID-19 in Ningbo was 3.06 (95%CI: 2.64- 3.51); according to the reported case transmission interval of 7.5 days in the literature, the R(0) was 3.32 (95%CI: 2.51-9.38). Conclusion: There is no age and gender specific differences in the Tg of clusters of COVID-19 cases in Ningbo, and COVID-19 has high infectivity and spreading power in early phase.

[The mechanism study of ouabain in inhibiting the growth of hepatocellular carcinoma cells by inhibiting the laser kinase signaling pathway]

Objective: To investigate the effect of Na(+)/K(+)-ATPase inhibitor ouabain on the proliferation and division of liver cancer HepG2 cells, and to explore the anticancer mechanism. Methods: HepG2 cells were exposed with different concentrations of ouabain (0.1, 1, 10 μmol/L) for 24 h, the proliferation ability was appraised using CCK-8, and the HepG2 cells was as a control group. The status of chromosome separation was detected with cell immunofluorescence (ICC) coupled to confocal microscope. The expression levels of AURKA, mTOR, p-mTOR, ERK and p-ERK protein were analyzed using western blot. Results: After treating with 0.1, 1 and 10 μmol/L of ouabain for 24 h, the inhibitory rate of cells were (23.5±4.57)%, (49.80±5.32)%, and (72.10±5.62)%, respectively. Ouabain could significantly inhibit the proliferation of HepG2, and presented in a dose-dependent manner(F=32.8, P<0.05). The ICC results showed that the chromosome separation disorders occurred in HepG2 cells treated with 1 μmol/L for 24 h, and the spindle diameter of HepG2 cells with ouabain treatment was decreased significantly compared with the control group(t=9.58, P<0.05). The results of western blot showed that the expression levels of AURKA, p-mTOR and p-ERK expressions in HepG2 cells treated with 1 μmol/L of ouabain were significantly decreased compared with the control group(F=16.26, 8.32, 33.59, P<0.05). Ouabain inhibited the growth of hepatocellular carcinoma cells in nude mice(F=370.20, P<0.05). Conclusion: Ouabain can induce chromosome division disorder and inhibit the proliferation in liver cancer HepG2 cells by inhibiting AURKA signaling pathway.

[Comparison on efficacy and safety of different bridging anticoagulation therapies in patients undergoing mechanical heart valve replacement surgery]

Objective: To evaluate the efficacy and safety of different bridging anticoagulant therapies in patients undergoing mechanical heart valve replacement (MHVR) surgery. Methods: Consecutive patients undergoing MHVR surgery from January 2018 to December 2018 in First Hospital of Lanzhou University were prospectively enrolled in this study. Patients were divided into unfractionated heparin (UFH) group and low molecular weight heparin (LMWH) group according to the postoperative bridging anticoagulation methods. Preoperative clinical data and postoperative related time and cost parameters, including drainage time, duration of stay in intensive care unit (ICU), postoperative time (interval from end of operation to discharge) and INR stabilization time (interval from start of bridge anticoagulation to INR value reaching the standard for 2 consecutive days) of all enrolled patients were collected, and all patients were followed up for 4 weeks and thromboembolic or bleeding events were analyzed. Multivariate logistic regression was used to determine the independent prognostic factors of thromboembolic or bleeding events after MHVR receiving various bridging anticoagulant therapies. Results: A total of 217 patients were included in the study, including 120 patients in the UFH group and 97 patients in the LMWH group. Stroke occurred in two patients in the UFH group, while no stroke event occurred in the LMWH group. The incidence of bleeding events was significantly higher (9.28%(9/97) vs. 1.67%(2/120), P=0.02), while the drainage time, duration of stay in ICU, postoperative time, INR stabilization time were all significantly shorter in LMWH group than in UFH group (all P<0.05). Multivariate logistic regression analysis showed that bridging anticoagulation therapies (OR=0.18, 95%CI 0.04-0.86, P=0.03), fibrinogen level (OR=1.99, 95%CI 1.16-3.41, P=0.01) and creatinine level (OR=1.05, 95%CI 1.01-1.08, P=0.04) were independent prognostic factors for bleeding events. Conclusion: LMWH use is associated with increased risk of bleeding events, but can significantly reduce the drainage time, duration of stay in ICU, postoperative time, INR stabilization time in patients post MHVR surgery.

VDJ Gene Usage of B Cell Receptors in Peripheral Blood of ABO-incompatible Kidney Transplantation Patients

INTRODUCTION

B cell subtypes and immunoglobulin variable (V), diversity (D), joining (J) gene segment usage of B cell receptors in ABO-incompatible (ABOi) kidney transplantation (KT) in comparison to ABO-compatible KT have not been studied. The aims of this study were to analyze the VDJ gene segment usages of B cell receptors in peripheral blood of ABOi KT recipients.

METHODS

Eighteen ABOi KT patients with accommodation (ABOiA), 10 ABO-compatible stable KT patients (ABOcS), and 10 ABOi KT patients with biopsy-proven acute antibody-mediated rejection (ABOiR) at day 10 after transplantation were selected. Complete transcriptomes of their peripheral blood samples were sequenced and analyzed through RNA sequencing.

RESULTS

By family, immunoglobulin heavy chain variable 3 (IGHV3), immunoglobulin light kappa chain variable 1 (IGKV1), immunoglobulin light lambda chain variable 2 (IGLV2), and immunoglobulin light lambda chain joining 3 (IGLJ3) gene segments were most frequently used in all groups, and their usage was not statistically different among the three groups except for IGHV3 and IGKV1. IGKV1 was more frequently used in the ABOiA group than in the ABOcS group. According to individual gene segments, IGHV3-7, IGHV3-15, IGHV4-59, IGKV3-11, IGLV1-44, IGLV2-14, IGLV4-69, and IGLV7-46 were more frequently used in the ABOcS group than other groups, and IGKV3-7 was more frequently used in the ABOiR group than other groups. IGLV5-52 and IGLV7-43 were more frequently used in the ABOiA group than in ABOcS group.

CONCLUSIONS

Our findings suggest that RNA sequencing transcriptomic analyses of peripheral blood can provide information on the VDJ gene usage of B cell receptors and the mechanisms of accommodation and immune reaction in ABOi KT.

[Effect of different parts of skull thickness on stereotactic electroencephalogram in children]

Objective: To investigate the thickness of cranial bone in different parts of children skull during stereotactic electroencephalogram (SEEG) and its effect on electrode fixation. Methods: From October 2016 to March 2017, 13 children with SEEG by robot of surgery assistant (ROSA) were selected. The basic case information and electrode design scheme were collected. The skull thickness of each electrode channel was measured on post-operation CT, and the loosening of the fixed screws were recorded. The thickness of skull in frontal bone, temporal bone, parietal bone and occipital bone was statistically processed by SPSS statistical software. Results: There were total 113 electrodes in 13 children with epilepsy. There were 45 electrodes at frontal bone, of which the thickness was (5.7±2.8)mm. There were 34 electrodes at temporal bone, of which the thickness was (3.5±1.3)mm.There were 16 electrodes at parietal bone, of which the thickness was (6.0±2.5)mm.There were 18 electrodes at occipital bone, of which the thickness was (6.9±0.5)mm. Statistics showed that there was significant difference between differnt bone (F=15.340, P<0.01). There were 4 electrodes loosening, 1 at frontal bone and 3 at temporal bone, when the screws were removed. There was no adverse event related to the implantation of electrodes. Conclusions: The children's skull thickness is thinner than adults. The screw loosening is exist in some cases, but it has no effect on SEEG recording. No SEEG related adverse events are found in this group. Therefore, ROSA guided SEEG is safe and reliable in children with epilepsy.

Effect of an acetylene bond on hydrogen adsorption in diamond-like carbon allotropes: from first principles to atomic simulation

Diamond-like diacetylene theoretically exhibits exceptional gravimetric and volumetric hydrogen storage capacities due to its abundant adsorption sites.

LXW7 ameliorates focal cerebral ischemia injury and attenuates inflammatory responses in activated microglia in rats

Inflammation plays a pivotal role in ischemic stroke, when activated microglia release excessive pro-inflammatory mediators. The inhibition of integrin αvβ3 improves outcomes in rat focal cerebral ischemia models. However, the mechanisms by which microglia are neuroprotective remain unclear. This study evaluated whether post-ischemic treatment with another integrin αvβ3 inhibitor, the cyclic arginine-glycine-aspartic acid (RGD) peptide-cGRGDdvc (LXW7), alleviates cerebral ischemic injury. The anti-inflammatory effect of LXW7 in activated microglia within rat focal cerebral ischemia models was examined. A total of 108 Sprague-Dawley rats (250–280 g) were subjected to middle cerebral artery occlusion (MCAO). After 2 h, the rats were given an intravenous injection of LXW7 (100 μg/kg) or phosphate-buffered saline (PBS). Neurological scores, infarct volumes, brain water content (BWC) and histology alterations were determined. The expressions of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)], and Iba1-positive activated microglia, within peri-ischemic brain tissue, were assessed with ELISA, western blot and immunofluorescence staining. Infarct volumes and BWC were significantly lower in LXW7-treated rats compared to those in the MCAO + PBS (control) group. The LXW7 treatment lowered the expression of pro-inflammatory cytokines. There was a reduction of Iba1-positive activated microglia, and the TNF-α and IL-1β expressions were attenuated. However, there was no difference in the Zea Longa scores between the ischemia and LXW7 groups. The results suggest that LXW7 protected against focal cerebral ischemia and attenuated inflammation in activated microglia. LXW7 may be neuroprotective during acute MCAO-induced brain damage and microglia-related neurodegenerative diseases.

[Efficiency of integrin αvβ3 inhibitor Cilengitide in acute cerebral ischemia in rats]

OBJECTIVE

To explore the effect of the integrin αvβ3 inhibitor Cilengitide on the blood brain barrier (BBB) permeability, brain edema, neuronal cell apoptosis and the relation with the vascular endothelial growth factor (VEGF)expression in acute cerebral ischemia rats.

METHODS

A rat focal cerebral ischemia/reperfusion model was established by middle cerebral artery occlusion. Rats with middle cerebral artery occlusion, in accordance with the random number table, were divided into four groups: (1) the rats in Cilengitide group A (n=30) were treated with Cilengitide at a dose of 100 μg/kg; (2) the rats in Cilengitide group B (n=28) were treated with Cilengitide at a dose of 200 μg/kg; (3) the rats in sham group (n=31), without inserting thread into middle cerebral artery, were treated with normal saline; (4) the rats in control group (n=27) were treated with normal saline.All rats were treated with Cilengitide or saline 1 hour after infarction, given reperfusion 2 hours after infarction and were sacrificed 22 hours after reperfusion.The brain-water content was measured by dry/wet weight method. The permeability of BBB was measured by quantifying Evans Blue. The infarction volume was measured by 2, 3, 5-tripheyl tetrazolium Chloride (TTC) staining. Expression level of VEGF, P-Flk, Cleaved-Caspase-3 was measured by immunohistochemistry and Western blot, respectively.The neuronal cell apoptosis was evaluated by terminal deoxynucleotidyl transferased UTP nick end labeling (TUNEL).

RESULTS

Compared with Control group, treatment groups with cilengitide at the dose of 100 μg/kg and 200 μg/kg reduced brain-water content [(80.8±1.1)% vs (84.8±1.4)%, (81.0±1.4)% vs (84.8±1.4)%, P<0.05], reduced exudation of Evans blue[(9.2±1.1) μg/g vs (12.2±0.8) μg/g, (8.6±0.6) μg/g vs (12.2±0.8) g/g, P<0.05], reduced infarction volume[(31.9±4.9) mm(3) vs(43.0±2.2) mm(3), (29.2±3.5) mm(3) vs(43.0±2.2) mm(3), P<0.05] , reduced neuronal cell apoptosis [(36±4)vs(69±6)、(35±3)vs (69±6), P<0.05]. Compared with sham group, Cilengitide group A and Cilengitide group B had lower brain-water content, permeability of BBB, infarction volume, expression level of VEGF, P-Flk, Cleaved-Caspase-3 and neuronal cell apoptosis (P<0.05). When Cilengitide group A was compared with Cilengitide group B, there were no significant differences in brain-water content, permeability of BBB, infarction volume, expression level of VEGF, P-Flk, Cleaved-Caspase-3 and neuronal cell apoptosis (P>0.05).

CONCLUSION

The integrin αvβ3 inhibitor Cilengitide improves outcomes in the MCAO model by preserving the blood-brain barrier, attenuating brain edema and inhibiting neuronal cell apoptosis, which may occur in a VEGF-and VEGF-receptor-dependent manner, with the same efficacy between Cilengitide 100 μg/kg and 200 μg/kg after 23 hours treatment.

Effects of humic acid and ionic strength on TiO₂ nanoparticles sublethal toxicity to zebrafish

The stability and bioavailability of titanium dioxide nanoparticles (TiO2 NPs) suspension could be modified by the physicochemical properties of solution. In the present study, the effect of humic acid (HA) and ionic strength (by adding NaCl) on aggregation and sedimentation of TiO2 NPs suspension were investigated. Accordingly, the sublethal toxicity of TiO2 NPs suspensions with different HA and NaCl concentrations toward zebrafish (Danio rerio) was evaluated by monitoring the changes of superoxide dismutase, catalase, malonaldehyde and glutathione in gill, liver and intestine. The results showed that the aggregations formation and hydrodynamic diameter of TiO2 NPs in suspensions are not essential characteristics to decide toxicity. The varied oxidative stress responses detected in gill, liver and intestine derived from different toxicity mechanisms of TiO2 NPs. Nevertheless, the oxidative stress could be suppressed by the adding of HA and/or the increase of ionic strength, which can decrease the bioavailability of TiO2 NPs in water. The study suggests that the environmental factors, such as HA and ionic strength, are important for the fate (aggregation and sedimentation) and toxicity of nanomaterials in aquatic environment.

Liquid immiscibility in an Fe-Cu alloy by molecular dynamics simulation

Liquid-liquid phase segregation in an Fe-Cu melt is investigated by molecular dynamics (MD) simulation based upon a newly developed embedded atom method due to Bonny. The partial pair correlation functions (PPCF) of liquid Fe(50)Cu(50) at a temperature of 1873 K show stronger interaction of homogeneous atom pairs. The coordination number (CN) of Cu-Cu and Fe-Fe in Fe(50)Cu(50) melt is about 11, much higher than that of Fe-Cu. Liquid-liquid phase segregation has also been observed clearly by the atom snapshot method. The calculated enthalpy of mixing is positive in the whole concentration range and the Bhatia-Thornton (BT) structure factor S(CC)(q) increases sharply at lower q, which are all typical features of dense fluid that exhibits a phase segregation tendency. Our present work provides an understanding of atomic-scale phase segregation in liquid Fe-Cu alloy.

Effects of Molecular Rigidity on Electric Field Induced Alignment and Orientational Stability of Dipolar Chromophore Composites

The relationship between the supramolecular conformational structure of assembled chromophores and their susceptibility to electric field poling is of interest for maximizing the bulk alignment achievable in an electro-optic material. We have employed solution phase dielectric constant measurements to investigate possible enhancements in dipolar susceptibility as a function of connectivity and state of aggregation in rationally synthesized chromophore assemblies, including conformationally defined head-to-tail oligomers. On the other hand, conformationally unrestricted, highly dipolar azo dyes behave as relatively isolated molecules even when present in supersaturated solutions and in close proximity on polymer chains.

Abstract P3-15-05: Muscle and Joint Symptoms in Breast Cancer Patients Receiving Taxane-Based Chemotherapy

Background: Docetaxel, paclitaxel, and (nab)-paclitaxel are taxanes used in treating breast cancer at various stages. While fairly well tolerated, they can cause distressing side effects. Both the prevalence and severity of muscle and joint symptoms (M&JS) in patients receiving taxane-based chemotherapies are poorly documented. We prospectively investigated the prevalence and severity of M&JS in women receiving taxane chemotherapy for breast cancer.

Methods: A total of 275 taxane-naive patients were enrolled in the study. This analysis presents data for 95 patients. For three consecutive treatmentcycles patients completed a baseline questionnaire as well as a diary, days 1 through 7 and on days 14 and 21 following treatment. Patient interviews were done by telephone days 2 to 3, and days 5 to 7 following treatment. They were then contacted at approximately three month intervals for one year. Data collection and data entry are ongoing; long term follow-up will conclude in August 2010.

Results: The average age of patients was 53 years. Disease status was classified as early for 50%, locally advanced for 35.34 %, and metastatic for 15.51% of patients. Overall 41.4% and 39.6% of patients reported muscle and joint pain, respectively, in their diaries on days 1 to 7. Muscle pain was most commonly reported in the legs, back, and arms and joint pain in the knees, ankles, and hips. The pain was most often described as aching, tiring, nagging, exhausting, and tender. The following scores are derived from a 10 cm visual analog scale. Of those who experienced pain in the seven days after treatment, the mean rating for pain at its worst was 5.15 and 5.02 for muscle and joint pain, respectively. Pain at its least had an average rating of 3.42 and 3.41 for muscle and joint pain, respectively. With respect to interference, patients who experienced pain had a mean score of 5.39, 4.86, 5.5, 4.12, 5.36, and 5.44 for interference with basic activities in daily life, mood, working or housework, relationships, sleeping and enjoyment of life, respectively. One, 3, 6, 9 and 12 months after taxane treatment ended, 27.2% (22/81), 31% (13/42), 45.5% (20/44), 37.2% (16/43), and 26.9% (7/26) reported muscle pain, respectively. Joint pain was reported by 26% (21/81), 38.1% (16/42), 43.2% (19/44), 48.8% (21/43) and 34.6% (9/26) of patients 1, 3, 6, 9 and 12 months following treatment, respectively. Data entry and analysis is ongoing and the final analysis will report on pain in relation to the taxane used, steroid tapering, role of anti-hormonal therapy, and effect of menopause on incidence of M&JS.

Discussion: Our preliminary data analysis indicates incidence rates of M&JS higher than previously reported during taxane treatment, and persistence of symptoms in a large proportion of patients up to a year following therapy completion. High pain scores and considerable interference with many aspects of life were reported. This study confirms the significant burden of M&JS during taxane chemotherapy. Conclusions: M&JS during taxane treatment is a common occurrence, and is significantly debilitating to the women who experience it. More research should be done regarding preventative measures and treatment options.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-15-05.

Immunoglobulin superfamily is conserved but evolved rapidly and is active in the silkworm, Bombyx mori

Immunoglobulin superfamily (IgSF) proteins are known for their abilities to specifically recognize and adhere to cells. In this paper, we predicted the presence of 133 IgSF proteins in the silkworm (Bombyx mori) genome. Comparison with similar proteins in other model organisms (Caenorhabditis elegans, Drosophila melanogaster, Anopheles gambiae, Apis mellifera and Homo sapiens) indicated that IgSF proteins are conserved but have rapidly evolved from worms to human beings. However, these proteins are well conserved amongst insects. Silkworm microarray-based expression data showed tissue expression of 57 IgSF genes and microbe-induced differential expression of 37 genes. Based on the expression data, we can conclude that the silkworm IgSF is active.

Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital of the Chinese People's Liberation Army

A worldwide outbreak of severe acute respiratory syndrome (SARS) had been reported. Over 8439 SARS cases and 812 SARS-related deaths were reported to the World Health Organization from 32 countries around the world up to 5 July 2003. The mechanism of transmission of SARS-CoV has been limited only to close contacts with patients. Attention was focused on possible transmission by the sewage system because laboratory studies showed that patients excreted coronavirus RNA in their stools in Amoy Gardens in Hong Kong. To explore whether the stool of SARS patients or the sewage containing the stool of patients would transmit SARS-CoV or not, we used a style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing, as well as cell culture, semi-nested RT-PCR and sequencing of genes to detect and identify the viruses from sewage. There was no live SARS-CoV detected in the sewage in these assays. The nucleic acid of SARS-CoV was found in the sewage before disinfection from both hospitals by PCR. After disinfection, SARS-CoV RNA could be detected from some samples from the 309th Hospital of the Chinese People's Liberation Army, but not from Xiao Tang Shan Hospital after disinfection. In this study, we found that the virus can survive for 14 days in sewage at 4 degrees C, 2 days at 20 degrees C, and its RNA can be detected for 8 days though the virus had been inactivated. In conclusion, this study demonstrates that the RNA of SARS-CoV could be detected from the concentrates of sewage of both hospitals receiving SARS patients before disinfection and occasionally after disinfection though there was no live SARS-CoV; thus much attention should be paid to the treatment of stools of patients and the sewage of hospitals receiving SARS patients.

Adoptive immunotherapy with donor lymphocyte infusions and interleukin-2 after high-dose therapy and autologous stem cell rescue for multiple myeloma

In an attempt to induce a graft-versus-myeloma effect, we administered donor lymphocyte infusions (DLI) after high-dose therapy with autologous stem cell transplant rescue to seven patients with refractory or relapsed multiple myeloma. High-dose therapy consisted of melphalan, idarubicin and etoposide (days -9 to -6) followed by autologous stem cell infusion on day 0. DLI (five of seven donors with two or three HLA antigens mismatched) were administered on days +1, +5 and +10 along with IL-2 (from day +1 through +12). Six of the seven patients developed acute graft-versus-host disease (GVHD), which resolved spontaneously, coincidentally with autologous hematopoietic reconstitution. One patient failed to engraft and received a second autologous graft. One patient died from complications of a pulmonary hemorrhage after experiencing GVHD. With a minimum follow-up of 38 months, five patients remain without disease progression in complete remission or with minimal residual disease. In this setting, DLI/IL-2 is biologically active resulting in GVHD. A graft-versus-myeloma effect is suggested by the improved outcome of our small cohort of high-risk patients. The use of partially mismatched related donors makes this approach potentially available to nearly all patients.

Conventional and surrogate light chains differentially regulate Ig mu and Dmu heavy chain maturation and surface expression

Positive selection of precursor (pre-) B cells by Ig membrane mu H chains (mum HC) and counterselection mediated by the truncated HC Dmu depend on the ability of each HC to form a pre-B cell receptor (pre-BCR) signaling complex with the surrogate L chain (SLC) components lambda5 and Vpre-B. To better understand how pre-BCR signaling output is determined by its Ig components and the SLC, we investigated the regulation of pre-BCR surface expression and HC secretory maturation in a new nonlymphoid system. We took this approach as a means to distinguish B-lineage-specific effects from pre-BCR-intrinsic properties that may influence these aspects of pre-BCR homeostasis necessary for signaling. As in pre-B cells, the SLC in nonlymphoid cells supported only a limited degree of mum HC maturation and low pre-BCR surface expression levels compared with conventional LCs, indicating that this was due to an intrinsic property of the SLC. We identified the non-Ig region of lambda5 as harboring the restrictive activity responsible for this phenotype. This property of lambda5 was also evident with Dmu, but the overall SLC- and L chain-dependent requirements for Dmu maturation and surface expression were markedly different from those for mum. Surprisingly, Dmu was modified in an unusual manner that was only dependent on Vpre-B. These results establish a novel function of lambda5 in limiting surface pre-BCR levels and reveal biochemical properties of Ig molecules that may underlie the diverse consequences of pre-BCR signaling in vivo by different HCs.