KYNU Expression Promotes Cisplatin Resistance in Esophageal Cancer.

Background: Chemotherapy resistance is a barrier to effective cancer prognoses. Cisplatin (CDDP) resistance is a major challenge for esophageal cancer (EC) therapy. A deeper understanding of the fundamental mechanisms of cisplatin resistance and improved targeting strategies are required in clinical settings. This study was performed to identify and characterize a marker of cisplatin resistance in EC cells. Method: KYSE140 and Eca-109 cells were subjected to escalating concentrations of cisplatin, resulting in the development of cisplatin-resistant KYSE140/CDDP and Eca-109/CDDP cell lines, respectively. RNA Sequencing (RNA-seq) was utilized to screen for the genes exhibiting differential expression between cisplatin-resistant and parental cells. Reverse transcription quantitative PCR was conducted to assess gene expression, and western blotting was employed to analyze protein levels. A sphere-formation assay was performed to validate tumor cell stemness. Cell counting kit-8 (CCK-8) experiments were conducted to confirm the sensitivity of cells to cisplatin. We examined the relationship between target genes and the clinicopathological features of patients with EC. Furthermore, the expression of target genes in EC tissues was evaluated via western blotting and fluorescence probe in situ hybridization (FISH). Results: KYNU was upregulated in cisplatin-resistant EC cells (KYSE140/CDDP and Eca-109/CDDP cells) and in EC tissues compared to that in the respective parental cell lines (KYSE140 and Eca-109 cells) and non-carcinoma tissues. Downregulation of KYNU increased cell sensitivity to cisplatin and suppressed tumor stemness, whereas abnormal KYNU expression had the opposite effect. KYNU expression was correlated with the expression of tumor stemness-associated factors (SOX2, Nanog, and OCT4) and the tumor size. Conclusions: KYNU may promote drug resistance in EC by regulating cancer stemness, and could serve as a biomarker and therapeutic target for EC.

Enhanced adsorption performance of oxytetracycline in aqueous solutions by Mg-Fe modified suaeda-based magnetic biochar.

Oxytetracycline (OTC) in the waste water can be removed by biochar adsorption. How to separate the biochar adsorbed antibiotics from the wastewater was also a problem. The nontoxic magnetic biochar was prepared from Suaeda biochar (800SBC) by mafic bimetal modification, and used for the removal of OTC. The results of XRD and VSM indicated that the main composition of biochar was ferrite. Then through batch adsorption experiments, the adsorption kinetics, isothermal adsorption, thermodynamics, and coexisting ion and adsorbent regeneration experiments were studied. Through the fitting of the adsorption model, it was found that Mg-Fe@800SBC(1:1) and 800SBC belonged to chemisorption. 800SBC was consistent with the Langmuir model, mainly monolayer adsorption, and Mg-Fe@800SBC(1:1) was consistent with the Freundlich model, mainly multilayer adsorption. The adsorption processes of the two materials were spontaneous, endothermic and entropic decreasing processes. The maximum adsorption capacity of the Mg-Fe@800SBC(1:1) for OTC from the Sips L-F model was 82.83 mg/g. Through various characterizations of magnetic biochar, it was found that the adsorption mechanism of the modified biochar included the hydrogen bonds between the oxygen-containing functional group of biochar and the -NH2 group of OTC, π-π EDA interaction, electrostatic attraction and complexation. Coexistence anions (CO32- and PO43-) have a negative effect on the adsorption process.

Gastric mucosal precancerous lesions in Helicobacter pylori-infected pediatric patients in central China: A single-center, retrospective investigation.

BACKGROUND: Helicobacter pylori (H. pylori) infects about 50% of the world population and is the major cause of chronic gastritis, peptic ulcers, and gastric cancer. Chronic H. pylori infection induces gastric mucosal precancerous lesions mostly in adulthood, and it is debatable whether these pathological conditions can occur in childhood and adolescents as well. Since this is a critical issue to determine if intervention should be offered for this population group, we investigated the gastric mucosal precancerous lesions in pediatric patients in an area in central China with a high prevalence of H. pylori and gastric cancer. AIM: To investigate the relationship of H. pylori infection and gastric mucosal precancerous lesions in children and adolescents in central China. METHODS: We screened 4258 ward-admitted children and adolescent patients with upper gastrointestinal symptoms, and finally enrolled 1015 pediatric patients with H. pylori infection and endoscopic and histological data. H. pylori infection status was determined by rapid urease test and histopathological examination. Both clinical and pathological data were collected and analyzed retrospectively. Occurrence of gastric mucosal precancerous lesions, inflammatory activity and degree of inflammatory cell infiltration between H. pylori-positive and -negative groups were compared. RESULTS: Among the 1015 eligible children and adolescents, the overall H. pylori infection rate was 84.14% (854/1015). The infection rate increased with age. The incidence of gastric mucosal precancerous lesions in H. pylori-infected children was 4.33% (37/854), which included atrophic gastritis (17 cases), intestinal metaplasia (11 cases) and dysplasia (9 cases). In H. pylori-negative patients, only 1 atrophic gastritis case [0.62%, (1/161)] was found (P < 0.05). Active inflammation in H. pylori-infected patients was significantly higher than that in non-infected patients, and the H. pylori-infected group showed more severe lymphocyte and neutrophil granulocyte infiltration (P < 0.001). In addition, endoscopy revealed that the most common findings in H. pylori-positive patients were antral nodularity, but in H. pylori-negative patients only superficial gastritis was observed. CONCLUSION: In children and adolescents, gastric mucosal precancerous lesions occurred in 4.33% of H. pylori-infected patients in central China. These cases included atrophic gastritis, intestinal metaplasia, and dysplasia. The data revealed an obvious critical issue requiring future investigation and intervention for this population group.

Family-based Helicobacter pylori infection status and transmission pattern in central China, and its clinical implications for related disease prevention.

BACKGROUND: Helicobacter pylori (H. pylori) has characteristics of family cluster infection; however, its family-based infection status, related factors, and transmission pattern in central China, a high-risk area for H. pylori infection and gastric cancer, have not been evaluated. We investigated family-based H. pylori infection in healthy households to understand its infection status, related factors, and patterns of transmission for related disease prevention. AIM: To investigate family-based H. pylori infection status, related factors, and patterns of transmission in healthy households for related disease prevention. METHODS: Blood samples and survey questionnaires were collected from 282 families including 772 individuals. The recruited families were from 10 selected communities in the greater Zhengzhou area with different living standards, and the family members' general data, H. pylori infection status, related factors, and transmission pattern were analyzed. H. pylori infection was confirmed primarily by serum H. pylori antibody arrays; if patients previously underwent H. pylori eradication therapy, an additional 13C-urea breath test was performed to obtain their current infection status. Serum gastrin and pepsinogens (PGs) were also analyzed. RESULTS: Among the 772 individuals examined, H. pylori infection rate was 54.27%. These infected individuals were from 246 families, accounting for 87.23% of all 282 families examined, and 34.55% of these families were infected by the same strains. In 27.24% of infected families, all members were infected, and 68.66% of them were infected with type I strains. Among the 244 families that included both husband and wife, spouse co-infection rate was 34.84%, and in only 17.21% of these spouses, none were infected. The infection rate increased with duration of marriage, but annual household income, history of smoking, history of alcohol consumption, dining location, presence of gastrointestinal symptoms, and family history of gastric disease or GC did not affect infection rates; however, individuals who had a higher education level showed lower infection rates. The levels of gastrin-17, PGI, and PGII were significantly higher, and PGI/II ratio was significantly lower in H. pylori-infected groups than in H. pylori-negative groups. CONCLUSION: In our study sample from the general public of central China, H. pylori infection rate was 54.27%, but in 87.23% of healthy households, there was at least 1 H. pylori-infected person; in 27.24% of these infected families, all members were infected. Type I H. pylori was the dominant strain in this area. Individuals with a higher education level showed significantly lower infection rates; no other variables affected infection rates.

Both family-based Helicobacter pylori infection control and management strategy and screen-and-treat strategy are cost-effective for gastric cancer prevention.

BACKGROUND: Helicobacter pylori (H. pylori) infection and its related diseases are substantial public health burden for highly infected areas. Recently, a novel family-based H. pylori infection control and management (FBCM) strategy is introduced for H. pylori infection prevention and control. However, its cost-effectiveness has not been evaluated. We conducted this health economic evaluation to investigate the cost-effectiveness of FBCM, screen-and-treat, and no-screen strategies in Chinese population. MATERIALS AND METHODS: Cost-effectiveness analysis was performed using decision tree and Markov model. Parameters required for the model were from published literatures and public databases, including health state utility, screening characteristics, treatment effectiveness, and medical costs for the three strategies. Outcomes were cost, quality-adjusted life year (QALY), incremental cost-effectiveness ratio (ICER). Uncertainty analysis was performed to verify the robustness of this model. RESULTS: To prevent gastric cancer in a cohort of 1 million asymptomatic Chinese families, FBCM and screen-and-treat strategies prevented 1010 and 1201 new gastric cancer cases, reduced 2809 and 3339 gastric cancer-related death, and saved 956,971 and 1,137,549 QALYs, respectively, when compared with no-screen strategy. Cost-effectiveness analysis showed that FBCM strategy cost $9.18/QALY, and screen-and-treat strategy cost $12.08/QALY for gastric cancer prevention when compared with no-screen strategy. One-way sensitivity analysis revealed that screening from younger age by both strategies are more cost-effective. When compared with FBCM strategy, screen-and-treat strategy saved 5.98% gastric cancer cases and 5.78% of gastric cancer deaths, but costed $9348 to reduce a gastric cancer case. Results are not sensitive to any variables, and probabilistic sensitivity analysis confirmed robustness of the results. CONCLUSIONS: Both FBCM and screen-and-treat strategies are cost-effective for gastric cancer prevention compared with no-screen strategy. Since FBCM is more practical and convenient, it may be an efficient and excellent cost-effective strategy for gastric cancer prevention in H. pylori and gastric cancer prevalent areas.

Metabolic profiling of lysophosphatidylcholines in chlorpromazine hydrochloride- and N-acetyl-p-amino-phenoltriptolide-induced liver injured rats based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry.

Chlorpromazine hydrochloride (CH) and N-acetyl-p-amino-phenoltriptolide (APAP) are typical acentral dopamine receptor antagonists and antipyretic analgesics in clinical applications, respectively. However, it has been reported that these 2 drugs could cause liver damage. Lysophosphatidylcholines (LPCs) have multiple physiological functions and are metabolized primarily in the liver, where it undergoes significant changes when the liver is damaged. In the study, 15 LPCs in the rat serum with CH- and APAP-induced liver injury were quantified based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry, and multivariate statistical analyses including principal component analysis (PCA) and orthogonal partial least squares discriminate analysis (OPLS-DA) were combined to understand CH- and APAP-induced liver injury from the perspective of LPC metabolic profiling. The quantitative results showed that there were significant changes in 10 LPCs and 5 LPCs after CH- and APAP-administration, separately. The results of PCA and OPLS-DA indicated that CH- and APAP-induced liver injury could be well distinguished by the LPC metabolic profiling, and 7 LPCs and 1 LPC biomarkers that could characterize CH- and APAP-induced liver damage in turn had been screened. This study will not only provide a new perspective for the clinical diagnosis of CH- and APAP-induced liver injury, but also offer a reference for further study of their hepatotoxicity mechanisms.

Rabeprazole plus amoxicillin dual therapy is equally effective to bismuth-containing quadruple therapy for Helicobacter pylori eradication in central China: A single-center, prospective, open-label, randomized-controlled trial.

BACKGROUND: Antibiotic resistance emerges as a major issue for Helicobacter pylori (H. pylori) treatment. High-dose dual therapy has recently shown encouraging results in H. pylori eradication, but it has yet to be validated in this H. pylori highly infected area; it is also not known if this concept can be extended to antibiotics other than amoxicillin, and factors that affect the eradication. We investigate if rabeprazole plus amoxicillin or furazolidone regimens could be a first-line therapy for H. pylori eradication, and factors that affect the curing rate. METHODS: This is a single-center, prospective, open-label, randomized-controlled trial. Naive patients (n=292) were randomly treated with bismuth-containing quadruple therapy (BQT), rabeprazole plus amoxicillin (RADT), or furazolidone (RFDT) groups. RADT and FADT use three times daily regimens. H. pylori diagnosis and eradication were determined and confirmed by 13 C-urea breath test. RESULTS: In per-protocol (PP) analysis, H. pylori eradication rate was 91.2% in BQT group, 89.6% in RADT, and 51.0% in RFDT group. In intention-to-treat (ITT) analysis, infection was eradicated in 86.7% of patients in BQT group, 85.8% in RADT, and 48.1% in RFDT groups, respectively. Noninferiority was confirmed between BQT and RADT groups. The incidence of side effects in BQT group was significantly higher than that in RADT group. Successful eradication was associated with lower body surface area (BSA) and low body mass index (BMI) in BQT group. Smoking and high BSA index reduced H. pylori eradication rate in RADT group. CONCLUSIONS: Rabeprazole-amoxicillin dual therapy is equally effective to the bismuth-containing quadruple therapy for H. pylori eradication with fewer side effects and saves use of one antibiotic per each treatment. Successful eradication is also associated with low BSA and non-smoking condition, which deserves future stratified analysis for refinement and optimization.

Metabolic profiling of 19 amino acids in triptolide-induced liver injured rats by gas chromatography-triple quadrupole mass spectrometry.

The liver is an important organ for amino acid metabolism, and its damage can be reflected in the changes of amino acid level in the body. Triptolide (TP) has broad anti-inflammatory and anti-tumor activities, but its clinical application is limited due to hepatotoxicity. In this work, a simple, accurate and sensitive gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS) method was developed and validated for evaluating the serum levels of amino acids from control and TP-induced liver injured rats, and chemometric analysis was employed for amino acid metabolic profiles analysis. It was found that 11 amino acids showed significant changes after TP administration, and they were mainly involved in 5 metabolic pathways that are phenylalanine, tyrosine and tryptophan biosynthesis, alanine, aspartate and glutamate metabolism, glutamine and glutamate metabolism, phenylalanine metabolism and arginine biosynthesis. Five amino acids including tyrosine, glutamine, glutamic acid, tryptophan and alanine were identified as biomarkers of TP hepatotoxicity by further analysis. These results indicated that the novel amino acid metabolic profiling study based on the GC-QqQ-MS/MS provided not only exact concentrations of serum amino acids, but also a prospective methodology for evaluation of chemically induced liver injury.

Whole family-based Helicobacter pylori eradication is a superior strategy to single-infected patient treatment approach: A systematic review and meta-analysis.

BACKGROUND: Two critical concerns during Helicobacter pylori (H. pylori) eradication are the successful eradication and recurrence. It is debatable whether whole family-based H. pylori treatment regimen might have any advantage over single-infected patient treatment approach in increasing eradication rate and reducing recurrence rate. We conduct systematic review and meta-analysis to compare the efficacy of these two treatment regimens in order to provide clinical practice a better option for H. pylori eradication. METHODS: Randomized controlled trials evaluating H. pylori eradication and recurrence in whole family-based treatment group (WFTG) versus single-infected patient treatment group (SPTG) were collected from published literature up to July 2020 from common databases. Pooled results were analyzed using either fixed-effect or random-effect model. Results were expressed as the odds ratio (OR) and 95% confidence interval (CI). RESULTS: A total of 1751 relevant articles were identified, and 12 studies were eligible for analysis. Among them: (a) Eight articles including 1198 patients were selected to analyze H. pylori eradication rate, pooled result showed that eradication rate of WFTG was higher than that of SPTG (OR=2.93; 95% CI 1.68-5.13). Stratified analysis showed that H. pylori eradication rate in WFTG were higher over SPTG in children subgroup, but had no difference in spouse subgroup. (b) Six studies including 881 patients were analyzed for recurrence rate between the two groups, pooled analysis showed that the overall recurrence rate of WFTG was lower than that of SPTG (OR=0.3; 95% CI 0.19-0.48). Stratified analysis showed that the recurrence rate in WFTG was lower over SPTG at 6, 12, 18, and more than 24 months post-treatment subgroups. CONCLUSION: Whole family-based H. pylori treatment can partially increase eradication rate and reduce recurrence rate over single-infected patient treatment approach, the results provide clinical practice a novel notion for H. pylori eradication and infection prevention.

Fouling analysis and permeate quality evaluation of mulberry wine in microfiltration process.

Sterilization and clarification are essential to produce wine of high quality and stability, microfiltration is a serious candidate for both purposes. In this work, microfiltration of fermented mulberry wine was evaluated for the first time. Four different commercial membranes, of two different materials (PES, PVDF) and two different nominal pore sizes (0.22 µm and 0.45 µm) were employed. Pore blocking model was used to identify the fouling mechanism, foulant constituents were revealed by FT-IR spectra. The effect of microfiltration on permeate quality of mulberry wine was also involved. The results indicated that cake formation was the dominant mechanism during steady-state of mulberry wine microfiltration, independently on the membrane property. The fouling layer was mainly composed of protein and polysaccharides, which induced basically reversible overall filtration resistance. Microfiltration delivered a superior clarity, highly polydisperse and light-color mulberry wine with a satisfactory sterilization stability. It preserved the main basic properties and organic acid contents of mulberry wine while resulted in certain loss of volatile compounds, especially esters and alcohols. This work has provided a scientific reference for producing mulberry wine, a modern functional beverage.

MicroRNA-139 inhibits the proliferation, migration and invasion of gastric cancer cells by directly targeting ρ-associated protein kinase 1.

The expression, function and underlying mechanisms of microRNA-139 (miR-139) in gastric cancer were investigated in the present study. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect miR-139 expression in gastric cancer tissues and cell lines. The effects of miR-139 overexpression on gastric cancer cell proliferation, migration and invasion were evaluated. ρ-associated protein kinase 1 (ROCK1) was predicted as a downstream target of miR-139 and its role in gastric cancer was assessed by bioinformatics analysis, luciferase reporter assay, RT-qPCR and western blot analysis. ROCK1 overexpression was established to investigate if the effects of miR-139 on gastric cancer cells may be attenuated. The results indicated that miR-139 was aberrantly downregulated in gastric cancer tissues and cell lines. Increased miR-139 expression reduced gastric cancer cell proliferation, migration and invasion. ROCK1 was demonstrated to be a direct target of miR-139 in gastric cancer and ROCK1 overexpression reversed the suppressive effects on gastric cancer cell proliferation, migration and invasion induced by miR-139 overexpression. The present study provides clear evidence demonstrating the anti-oncogenic activity of miR-139 in human gastric cancer, as mediated by the targeted downregulation of ROCK1.

MicroRNA-363-3p is downregulated in hepatocellular carcinoma and inhibits tumorigenesis by directly targeting specificity protein 1.

microRNAs exhibit important regulatory roles in tumorigenesis and tumor development, such as in hepatocellular carcinoma (HCC). The present study aimed to investigate the expression and functional roles of microRNA (miR)­363­3p in HCC. miR-363-3p expression levels in a number of HCC tissues and cell lines were measured by reverse transcription-quantitative PCR (RT­qPCR). The effects of miR­363­3p expression on HCC cell proliferation, migration and invasion were exa-mined by MTT assay, Transwell migration and invasion assay, respectively. The effects of miR­363­3p on its downstream target gene, specificity protein 1 (SP1), were examined by bioinformatics analysis, luciferase reporter assay, RT­qPCR and western blotting. An SP1 overexpression vector was subsequently transfected into HCC cells to assess any selective effects on miR­363­3p in modulating HCC. The results revealed that miR­363­3p expression levels were downregulated in both HCC tissues and cell lines, and this low expression level was correlated with tumor size, tumor­node­metastasis stage and venous infiltration in patients with HCC. Upregulation of miR­363­3p inhibited cell proliferation, migration and invasion in HCC cell cultures. In HCC cells transfected with an SP1 expression vector the miR­363­3p­induced tumor suppressive roles on cell proliferation, migration and invasion were reversed. In conclusion, results from the present study indicated that miR­363­3p is a tumor suppressor in HCC and functions through a mechanism involving SP1, suggesting that miR­363­3p may be a potential new therapeutic target for the treatment of HCC.

Cap formation engineering: from opened C60 to single-walled carbon nanotubes.

Structural control, and especially chirality control, remains a significant challenge in the synthesis of single-walled carbon nanotubes (SWNTs). We report herein a rational approach to engineering fullerene caps for growing SWNTs with controlled structures via chemical vapor deposition (CVD). Opening of fullerendione via thermal oxidation yields hemispherical caps which can initiate SWNT growth at their open ends. The size and structure of these caps can be engineered by tuning the temperature of thermal oxidation. Results show that pregrowth treatment of the cap is indispensable to successful growth of SWNTs. The temperature used for thermal oxidation strongly affects the size and structure of the cap and further determines the diameter distribution of the as-grown SWNTs. Stronger oxidation treatments (450 degrees C oxidation in air) promote formation of thinner SWNTs, while weaker oxidation treatments (350 degrees C oxidation in air) lead to wider SWNTs. Interestingly, SWNTs made using fullerene caps show steplike diameter distributions relative to SWNTs catalyzed by Fe nanoparticles. This cap engineering using opened C(60) provides a potential approach to grow SWNTs with controlled structures.

Diurnal variation of number concentration and size distribution of ultrafine particles in the urban atmosphere of Beijing in winter.

Number concentration and distribution of airborne particles in the size range 5.6 to 560 nm diameter were measured in Beijing for a 15-d period in winter 2005. Daily average number concentrations of nucleation mode (5.6-20 nm), Aitken mode (20-100 nm), and accumulation mode (100-560 nm) particles, and total particles were 17500, 32000, 4000, and 53500 cm(-3), respectively. Average particle size distribution was monomodal with a mode diameter of about 40 nm at night and bimodal with mode diameters of about 10 and about 40 nm during the daytime. New particle formation events, which were connected to diurnal variation of nucleation mode particles, were observed in more than half of the observation days. The events often started around 10:00-11:00 Chinese Standard Time (CST) and ended up after 3-4 h. Concentrations of Aitken and accumulation mode particles increased from midnight and reached their maxima at about 10:00 CST, and then decreased and became the lowest in the afternoon. Analysis of diurnal cycles in traffic volume and meteorological parameters revealed that the accumulation of the particles in Aitken and accumulation modes in the morning was influenced by formation of an inversion and increase in vehicle emission, and dispersion of such particles in the afternoon was associated with more effective vertical mixing and higher wind speed.

Cantilever dynamics and quality factor control in AC mode AFM height measurements.

We show that inconsistent-imaging dynamics, in which the cantilever oscillates in the attractive regime on substrate background but in the repulsive regime on sample, leads to artifacts in apparent height in AC mode Atomic force microscopy. Active Q control can be used to effectively tune the imaging dynamics. Increased effective Q promotes the attractive regime, improves imaging sensitivity, and results in less invasive imaging of soft biological molecules.

Thermochemical hole burning on a triethylammonium bis-7,7,8,8-tetracyanoquinodimethane charge-transfer complex using single-walled carbon nanotube scanning tunneling microscopy tips.

The present article describes a thermochemical hole burning (THB) effect on a charge-transfer complex triethylammonium bis-7,7,8,8-tetracyanoquinodimethane (TEA(TCNQ)(2)) using single-walled carbon nanotube (SWNT) scanning tunneling microscopy (STM) tips, which demonstrates the possibility of optimizing the THB storage materials and the writing tips for ultrahigh-density data storage. TEA(TCNQ)(2) is proven to be a high-performance THB storage material, which gives deeper holes and larger hole depth-to-diameter ratio as compared to the previous materials dipropylammonium bis-7,7,8,8-tetracyanoquinodimethane and N-methyl-N-ethylmorpholinium bis-7,7,8,8-tetracyanoquinodimethane. Instead of conventional Pt/Ir STM tips, SWNT tips made by a unique chemical assembly technique we developed have been shown to be excellent writing tips for greatly decreasing the hole sizes and increasing the storage density. Possible reasons for the improvements on the storage performance were discussed.

Thermochemical hole burning on a series of N-substituted morpholinium 7,7,8,8-tetracyanoquinodimethane charge-transfer complexes for data storage.

We demonstrate here the thermochemical hole burning (THB) effect on a series of N-substituted morpholinium 7,7,8,8-tetracyanoquinodimethane charge-transfer (C-T) complexes for ultra-high-density data storage. A correlation between the decomposition temperature of the charge-transfer complex and the threshold voltage of hole burning was observed: the higher the decomposition temperature, the larger the writing threshold value, suggesting the possibility of molecular design for optimizing the hole burning performance. The macroscopic decomposition properties of these charge-transfer complexes were studied by thermal gravimetry combined with mass spectrometry. Theoretical estimation of the temperature rise induced by scanning tunneling microscopy current heating was also conducted, which indicated that the maximum temperature certainly exceeds the decomposition temperatures of these C-T complexes. These observations are consistent with the thermochemical hole burning mechanism.

Application of ion chromatography to the determination of water-soluble inorganic and organic ions in atmospheric aerosols.

A simple, sensitive and convenient ion chromatography(IC) method was established for the simultaneous determination of twelve water-soluble inorganic anions(F- , Cl- , NO2(-), NO3(-), SO3(2-), SO4(2-) , PO4(3-)), and fifteen water-soluble organic ions(formate, acetate, MSA, oxalate, malonate, succinate, phthalates, etc.) in atmospheric aerosols. The linear concentrations ranged from 0.005 microg/m3 to 500 microg/m3 ( r = 0.999-0.9999). The relative standard deviation (RSD) were 0.43%-2.00% and the detection limits were from 2.7 ng/m3 to 88 ng/m3. The proposed method was successfully applied to the simultaneous determination of those inorganic ions and organic ions in PM2.5 of Beijing.

Daily concentrations of trace metals in aerosols in Beijing, China, determined by using inductively coupled plasma mass spectrometry equipped with laser ablation analysis, and source identification of aerosols.

This paper describes the daily concentrations of trace metals and ionic constituents in the aerosol of Beijing, China from March 2001 to August 2003. Daily PM10 concentrations were also measured from September 2001 to August 2003. The daily average PM10 concentration at Beijing, China from September 2001 to August 2003 was 171+/-117 microg m(-3) (n = 673), which is 5-fold higher than at Yokohama, Japan. Trace metal concentrations were analyzed by using inductively coupled plasma mass spectrometry equipped with a laser ablation sample introduction (LA/ICP-MS), which is a rapid and simultaneous method for multi-element analysis. The daily average metal concentrations in TSP in Beijing from March 2001 to August 2003 were: Al: 3.5+/-2.4 (n = 727), Ti: 0.47+/-0.35 (n = 720), V: 0.013+/-0.010 (n = 716), Cr: 0.019+/-0.015 (n = 618), Mn: 0.24+/-0.16 (n = 730), Fe: 5.5+/-3.9 (n = 728), Co: 0.0046+/-0.0055 (n = 629), Ni: 0.022+/-0.024 (n = 680), Cu: 0.11+/-0.11 (n = 660), Zn: 0.77+/-0.60 (n = 726), As: 0.048+/-0.047 (n = 731), Se: 0.010+/-0.010 (n = 550), Cd: 0.0068+/-0.0082 (n = 709), Sb: 0.033+/-0.036 (n = 687), and Pb: 0.43+/-0.50 (n = 728) (unit, microg m(-3)). All the metal concentrations in TSP in Beijing, China were 1.7-21.8 times higher than those in TSP in the center of Tokyo, Japan. Notably, As concentrations in TSP in Beijing were 20-fold higher than those in Tokyo. Source identification of aerosols in Beijing was carried out by using the chemical mass balance (CMB) receptor model, with the daily concentration of metals in the aerosol. The major primary sources of the aerosol of Beijing were considered to be soil dust and coal combustion. Vehicle exhaust contribution tended to increase.

[Environmental effect analysis for four stage measures of short-term air pollution control in Beijing].

The new emission inventories of Beijing city were developed based on the Four Stage Measures of Short-term Air Pollution Control implemented by Beijing municipal government. The concentrations of primary air pollutants SO2, NOx and PM10 in urban area during the time period of the Four Stages were simulated by an air quality model. It was shown that those measures have significant effects on the reductions of emissions and environmental concentrations of SO2 and NOx, while for PM10, the control strategies were not so effective.