Historical emission and reduction of VOCs from the petroleum refining industry and their potential for secondary pollution formation in Guangdong, China.

China became the world leader in crude oil processing capacity in 2021. However, petroleum refining generates significant volatile organic compound (VOC) emissions, and the composite source profile, source-specific emission factors, and emission inventories of VOCs in the petroleum refining industry remain poorly understood. In this study, we focused on Guangdong, China's major province for crude oil processing, and systematically evaluated the historical emissions and reduction of VOCs in the petroleum refining industry from 2001 to 2020. We accomplished this by establishing local source-specific emission factors and composite source profiles. Finally, we quantitatively assessed the potential impact of these emissions on ozone and secondary organic aerosol formation. Our results revealed that VOC emissions from the petroleum refining industry in Guangdong followed an increasing-then-decreasing trend from 2001 to 2020, peaking at 37.3 Gg in 2016 and declining to 18.7 Gg in 2020. Storage tanks and wastewater collection and treatment remained the two largest sources, accounting for 41.9 %-53.4 % and 20.6 %-27.5 % of total emissions, respectively. Initially, Guangzhou and Maoming made the most significant contributions, with Huizhou becoming a notable contributor after 2008. Emission reduction efforts for VOCs in Guangdong's petroleum refining industry began showing results in 2017, with an average annual VOC emission reduction of 21.5 Gg from 2017 to 2020 compared to the unabated scenario. Storage tanks, wastewater collection and treatment, and loading operations were the primary sources of emission reduction, with significant contributions from Maoming, Huizhou, and Guangzhou. Alkanes made the largest contribution to VOC emissions, while alkenes/alkynes and aromatics comprised the most significant portions of ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAP). We also estimated VOC emissions and reduction from petroleum refining for China from 2001 to 2020, and measures such as "one enterprise, one policy" and deep control strategies could reduce emissions by at least 103.9 Gg.

Supercritical Fluid-Assisted Fabrication of Pd Nanoparticles/Graphene Using a Choline Chloride-Oxalic Acid Deep Eutectic Solvent for Enhancing the Electrochemical Oxidation of Glycerol.

A green method for synthesizing Pd nanoparticles/graphene composites from a choline chloride-oxalic acid deep eutectic solvent (DES) without a reducing agent or a surfactant is reported. Deep eutectic solvents are usually composed of halide salts and hydrogen-bond donors, and many are biocompatible and biodegradable. The merits of deep eutectic solvents include that they serve as reducing agents and dispersants, and Pd nanoparticles are tightly anchored to graphene. The size and dispersion of Pd particles are improved when supercritical carbon dioxide (scCO2) is used because it has gaslike diffusivity and near-zero surface tension, which results in excellent wettability between the scCO2 and the carbon surface. The prepared sc-Pd NPs/GR/SPCE shows excellent activity toward glycerol oxidation compared to composites not fabricated by scCO2 processes. This study demonstrates the potential of using this scCO2-assisted protocol combined with deep eutectic solvents to further construct nanoparticles/graphene composites.

Optimized neural network for daily-scale ozone prediction based on transfer learning.

Tropospheric ozone (O3) pollution is worsening in China, and an accurate forecast is a prerequisite to lower the O3 peak level. In recent years, machine learning techniques have attracted increasing attention in O3 prediction owing to their high efficiency and simple operation. However, the accuracy of predicting the daily O3 level is low. This study proposed a novel model by coupling long short-term memory neural network with transfer learning (TL-LSTM), with meteorology and pollutant concentration information as the model input. L2 regularization was applied to reduce the risk of overfitting and to improve the accuracy and generalization ability of the model prediction. Our results indicated that by transferring the knowledge in the model configuration from the hourly LSTM module, TL-LSTM greatly improves the predictability of the daily maximum 8 h average (MDA8) of O3 in Hong Kong. The coefficient of determination (R2) increased from 0.684 to 0.783 and the mean square error (MSE) reduced from 1.36 × 10-2 to 1.05 × 10-2. Furthermore, R2 and MSE were the highest in summer, indicating an under-prediction of peak O3 levels. This was a result of the limited number of high O3 days, which did not provide sufficient knowledge for the model to make an accurate prediction. Sobol analysis indicated that wind speed was the most sensitive factor in O3 prediction, largely due to the development of land-sea breeze circulation which effectively traps pollutants and expedites O3 formation. The results clearly demonstrate the effectiveness of the TL-LSTM in predicting the daily O3 concentration in Hong Kong. Thus, TL-LSTM can be promulgated into other photochemically active regions to assist in O3 pollution forecasting and management.

Identification of close relationship between large-scale circulation patterns and ozone-precursor sensitivity in the Pearl River Delta, China.

To curb the continuous deterioration of ozone (O3) pollution in China, identifying the O3-precursor sensitivity (OPS) and its driving factors is a prerequisite for formulating effective O3 pollution control measures. Traditional OPS identification methods have limitations in terms of spatiotemporal representation and timeliness; therefore, they are not appropriate for making OPS forecasts for O3 contingency control. OPS is not only influenced by local precursor emissions but is also closely related to meteorological conditions governed by large-scale circulation (LSC). In this study, a localized three-dimensional numerical modeling system was used to investigate the relationship between LSC and OPS in the Pearl River Delta (PRD) of China during September 2017, a month with continuous O3 pollution. Our results highlighted that there was a close relationship between LSC and OPS over the PRD, and the four dominant LSC patterns corresponded well to the NOx-limited, NOx-limited, VOC-limited, and transitional regimes, respectively. The clear linkage between LSC and OPS was mainly driven by the spatial heterogeneity of NOx and VOC emissions within and beyond the PRD along the prevailing winds under different LSC patterns. A conceptual model was developed to highlight the intrinsic causality between the LSC and OPS. Because current technology can accurately forecast LSC 48-72 h in advance, the LSC-based OPS forecast method provided us with a novel approach to guide contingency control and management measures to reduce peak O3 at a regional scale.

The potential of adoptive transfer of γ9δ2 T cells to enhance blinatumomab's antitumor activity against B-cell malignancy.

Blinatumomab, a bispecific T cell engager (BiTE) antibody targeting CD19 and CD3ε, can redirect T cells toward CD19-positive tumor cells and has been approved to treat relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL). However, chemotherapeutic regimens can severely reduce T cells' number and cytotoxic function, leading to an inadequate response to blinatumomab treatment in patients. In addition, it was reported that a substantial portion of R/R B-ALL patients failing blinatumomab treatment had the extramedullary disease, indicating the poor ability of blinatumomab in treating extramedullary disease. In this study, we investigated whether the adoptive transfer of ex vivo expanded γ9δ2 T cells could act as the effector of blinatumomab to enhance blinatumomab's antitumor activity against B-cell malignancies in vivo. Repeated infusion of blinatumomab and human γ9δ2 T cells led to more prolonged survival than that of blinatumomab or human γ9δ2 T cells alone in the mice xenografted with Raji cells. Furthermore, adoptive transfer of γ9δ2 T cells reduced tumor mass outside the bone marrow, indicating the potential of γ9δ2 T cells to eradicate the extramedullary disease. Our results suggest that the addition of γ9δ2 T cells to the blinatumomab treatment regimens could be an effective approach to enhancing blinatumomab's therapeutic efficacy. The concept of this strategy may also be applied to other antigen-specific BiTE therapies for other malignancies.

[Optimization Method and Case Study of Air Pollution Emission Spatial Pattern].

Few of the current methods of improving air quality, including end-pipe treatment, industrial, energy and transportation structure adjustments, are from the viewpoint of the spatial pattern optimization of pollutant emissions. Therefore, based on factors such as natural environment, human health, pollutant transmission capability, and meteorological diffusion conditions, our research group used the threshold approach, natural breaks, spatial erasure, and other methods to define the layout area suitable for atmospheric pollution sources. Based on these results, the emissions pattern was optimized to achieve air quality improvement. Taking Guangdong Province as an example, we examined the application of the emissions pattern optimization of air quality improvement and atmospheric environment zoning. The results indicate that the first class area of environmental air quality accounts for 9% of total province area, the densely populated area accounts for 3%, the sensitive area of the national air quality monitor stations accounts for 15%, the pollutant accumulation area accounts for 22%, and the layout area suitable for atmospheric pollution sources primarily distributed in the west part of the province accounts for 60%. By shifting the non-thermal power industrial sources into those area, the concentration level of PM2.5 will decrease by 4% at the provincial scale and 10% at the city scale. Emissions pattern optimization has become an innovative aided support technology for the continuous improvement of air quality. In practical applications, it can be combined with energy and industrial structure adjustments, pollution control technology enhancements, and cross-regional prevention and control to formulate the most feasible air quality improvement plan.

Association of change in air quality with hospital admission for acute exacerbation of chronic obstructive pulmonary disease in Guangdong, China: A province-wide ecological study.

AIMS: To assess possible effect of air quality improvements, we investigated the temporal change in hospital admissions for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) associated with pollutant concentrations. METHODS: We collected daily concentrations of particulate matter (i.e., PM2.5, PM10 and PMcoarse), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and admissions for AECOPD for 21 cities in Guangdong from 2013 to 2017. We examined the association of air pollution with AECOPD admissions using two-stage time-series analysis, and estimated the annual attributable fractions, numbers, and direct hospitalization costs of AECOPD admissions with principal component analysis. RESULTS: From 2013-2017, mean daily concentrations of SO2, PM10 and PM2.5 declined by nearly 40%, 30%, and 26% respectively. As the average daily 8 h O3 concentration increased considerably, the number of days exceeding WHO target (i.e.,100 µg/m³) increased from 103 in 2015-152 in 2017. For each interquartile range increase in pollutant concentration, the relative risks of AECOPD admission at lag 0-3 were 1.093 (95% CI 1.06-1.13) for PM2.5, 1.092 (95% CI 1.08-1.11) for O3, and 1.092 (95% CI 1.05-1.14) for SO2. Attributable fractions of AECOPD admission advanced by air pollution declined from 9.5% in 2013 to 4.9% in 2016, then increased to 6.0% in 2017. A similar declining trend was observed for direct AECOPD hospitalization costs. CONCLUSION: Declined attributable hospital admissions for AECOPD may be associated with the reduction in concentrations of PM2.5, PM10 and SO2 in Guangdong, while O3 has emerged as an important risk factor. Summarizes the main finding of the work： Reduction in PM may result in declined attributable hospitalizations for AECOPD, while O3 has emerged as an important risk factor following an intervention.

Association of hospital admission for bronchiectasis with air pollution: A province-wide time-series study in southern China.

The relation of acute fluctuations of air pollution to hospital admission for bronchiectasis remained uncertain, and large-scale studies were needed. We collected daily concentrations of particulate matter (PM), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and daily hospitalizations for bronchiectasis for 21 cities across Guangdong Province from 2013 through 2017. We examined their association using two-stage time-series analysis. Our analysis was stratified by specific sub-diagnosis, sex and age group to assess potential effect modifications. Relative risks of hospitalization for bronchiectasis were 1.060 (95%CI 1.014-1.108) for PM10 at lag0-6, 1.067 (95%CI 1.020-1.116) for PM2.5 at lag0-6, 1.038 (95%CI 1.005-1.073) for PMcoarse at lag0-6, 1.058 (95%CI 1.015-1.103) for SO2 at lag0-4, 1.057 (95%CI 1.030-1.084) for NO2 at lag0 and 1.055 (95%CI 1.025-1.085) for CO at lag0-6 per interquartile range increase of air pollution. Specifically, acute fluctuations of air pollution might be a risk factor for bronchiectasis patients with lower respiratory infection but not with hemoptysis. Patients aged ≥65 years, and female patients appeared to be particularly susceptible to air pollution. Acute fluctuations of air pollution, particularly PM may increase the risk of hospital admission for bronchiectasis exacerbations, especially for the patients complicated with lower respiratory infection. This study strengthens the importance of reducing adverse impact on respiratory health of air pollution to protect vulnerable populations.

Association of diurnal temperature range with daily hospitalization for exacerbation of chronic respiratory diseases in 21 cities, China.

BACKGROUND: The association between diurnal temperature range (DTR) and hospitalization for exacerbation of chronic respiratory diseases (CRD) was rarely reported. OBJECTIVES: To examine the association between DTR and daily hospital admissions for exacerbation of CRD and find out the potential effect of modifications on this association. METHOD: Data on daily hospitalization for exacerbation of chronic obstructive pulmonary disease (COPD), asthma and bronchiectasis and meteorology measures from 2013 through 2017 were obtained from 21 cities in South China. After controlling the effects of daily mean temperature, relative humidity (RH), particulate matter < 2.5 µm diameter (PM2.5) and other confounding factors, a standard generalized additive model (GAM) with a quasi-Poisson distribution was performed to evaluate the relationships between DTR and daily hospital admissions of CRD in a two-stage strategy. Subgroup analysis was performed to find potential modifications, including seasonality and population characteristics. RESULT: Elevated risk of hospitalization for exacerbation of CRD (RR = 1.09 [95%CI: 1.08 to 1.11]) was associated with the increase in DTR (the 75th percentile versus the 25th percentile of DTR at lag0-6). The effects of DTR on hospital admissions for CRD were strong at low DTR in the hot season and high DTR in the cold season. The RR (the 75th percentile versus the 25th percentile of DTR at lag0-6) of hospitalization was 1.11 (95%CI: 1.08 to 1.12) for exacerbations of COPD and 1.09 (95%CI: 1.05 to 1.13) for asthma. The adverse effect of DTR on hospitalization for bronchiectasis was only observed in female patients (RR = 1.06 [95%CI: 1.03 to 1.10]). CONCLUSION: Our study provided additional evidence for the association between DTR and daily hospitalization for exacerbation of CRD, and these associations are especially stronger in COPD patients and in the cold season than the hot season. Preventive measures to reduce the adverse impacts of DTR were needed for CRD patients.

[Source Apportionment of Air Pollutants for a Typical Pollution Event in Zhaoqing].

Based on observational data for pollutants and meteorology, this study analyzed the pollution episode that occurred during Dec 17th to 23th in 2018 in Zhaoqing, Guangdong Province, China. Using the source apportionment model CMAQ-ISAM and the hybrid receptor model, the regional contributions to air pollution were examined. The results showed that low-pressure conditions had an adverse effect on the diffusion of pollutants during this pollution episode in Zhaoqing. Prior to the pollution episode, pollutants were mainly derived from Zhaoqing and Qingyuan, accounting for 19.2% and 10.7% of pollutants, respectively. As well as pollutants from Guangdong Province, long-distance transport of pollutants from Jiangxi, Hunan, Hubei, and Shaanxi accounted for approximately 64.5% of the total during the non-pollution period. During the polluted episode, major cities in Pearl River Delta and the eastern part of Guangdong Province contributed more pollutants as a surface high-pressure field moved southward. Zhaoqing, Foshan, Dongguan, Guangzhou, and Huizhou contributed 25.5%, 14.8%, 9.8%, 9.5%, and 5.3% of the pollutants, respectively. Cities in the eastern part of Guangdong Province including Heyuan, Meizhou, Shanwei, Jieyang, Shantou, and Chaozhou contributed 13.7% of the total pollutants. In addition, pollutants from Fujian, Jiangxi, and the Yangtze River Delta accounted for approximately 32.9%. Furthermore, pollutants transported under marine influences were one of the main causes of this pollution episode in Zhaoqing.

[Emission Inventory of Atmospheric Pollutants and VOC Species from Crop Residue Burning in Guangdong Province].

An emission inventory of atmospheric pollutants from crop residue burning in Guangdong for the period 2008-2016 was developed, based on crop yield data. Emissions of species of volatile organic compounds(VOCs)and corresponding ozone formation potential (OFP) in 2016 were also estimated. Results showed that emissions of atmospheric pollutants from crop residue burning in 2013-2016 were lower than in 2008-2012. This was mainly due to the policy of prohibiting open burning of straw and to improvement of rural living standards, which reduced the proportion of straw burning. In 2016, emissions of SO2, NOx, NH3, CH4, EC, OC, NMVOC, CO, and PM2.5 were 2443.7, 16187.9, 6943.8, 29174.4, 3625.5, 14830.7, 65612.6, 591613.9, and 49463.0 t, respectively. Rice straw burning was the main source of pollutants, accounting for about 68.55% of total pollutant emissions. The five municipalities with highest atmospheric pollutant emissions were Zhanjiang, Maoming, Meizhou, Zhaoqing, and Shaoguan, together accounting for about 58.63% of total emissions. The top 10 VOC species for mass-based emissions consisted of ethylene, acetaldehyde, formaldehyde, benzene, ethyne, propylene, ethane, toluene, propane, and propionaldehyde, together contributing 67.91% to total emissions. The top ten OFP-based VOC species were ethylene, formaldehyde, acetaldehyde, propylene, 1-butylene, propionaldehyde, toluene, acrolein, isoprene, and crotonaldehyde, accounting for 80.83% of total OFP.

[Air Quality Subarea Management:A Case Study of Guangdong Province].

To meet the requirements of regional air quality management (AQM), the Air Quality Subarea Management (AQSM) system was proposed. A case study was conducted for Guangdong Province. By using the method of air quality numerical simulation and satellite remote sensing inversion analysis, the key factors were selected from the meteorological simulation field, the pollutant concentration simulation field, and the satellite image interpretation to form the index system for AQSM. On this basis, a hierarchical cluster analysis method was used to divide Guangdong Province into three types of AQSM:Strict Control Subarea, Continuous Improvement Subarea, and Coordinated Development Subarea. It was shown that the Strict Control Subarea, Continuous Improvement Subarea, and Coordinated Development Subarea in Guangdong Province covered 16.3%, 28.0%, and 55.7%, respectively. The Strict Control Subarea in the Pearl River Delta, Eastern Guangdong, Western Guangdong, and Northern Guangdong accounted for 27.9%, 19.3%, 4.4%, and 12.5%, respectively, and the subarea should implement the most stringent AQM policies to promote air quality improvement. The Continuous Improvement Subarea in the Pearl River Delta, Eastern Guangdong, Western Guangdong, and Northern Guangdong accounted for 34.4%, 15.8%, 7.8%, and 34.5%, respectively, and the subarea should implement relatively strict AQM policies to ensure sustained and stable standards. The Coordinated Development Subarea in the Pearl River Delta, Eastern Guangdong, Western Guangdong, and Northern Guangdong accounted for 37.7%, 64.9%, 87.8%, and 53.0%, respectively, and the subarea could implement more liberal AQM policies to ensure relatively good air quality. In general, the strict AQM policies in Guangdong Province should be mainly concentrated in the Pearl River Delta region, followed by Northern Guangdong, Eastern Guangdong, and Western Guangdong in order.

[Capacity Simulation Method Based on Regional Transfer Matrix and PM2.5 Concentration Target Constraint].

Atmospheric environmental capacity is an important reference in environmental planning. To meet the PM2.5 standard, a new method is proposed to balance the capacity among cities of Guangdong, with screening of the most unfavorable meteorological year and combining it with the regional transportation calculated by the CAMx-PSAT module. Pollutant overloading and capacity scenarios were also calculated. The results showed that, under the constraints of the cities' annual PM2.5 ≤ 35 µg·m-3, the capacities of SO2, NOx, NH3, and PM2.5 in Guangdong were about 6.8×105 tons, 1.35×106 tons, 4.6×105 tons, and 5.1×105 tons, respectively. Based on the benchmark scenario, SO2 emissions in Guangdong were overloaded by 10%, and the emissions of NOx, NH3, and PM2.5 exceeded by 12%, 9%, and 20%, respectively, compared to those of the capacity scenario. Ranked by the number of overloaded species in Guangdong, the cities of Guangzhou, Foshan, Zhongshan, and Qingyuan were on top. When achieving the capacity scenario, the annual PM2.5 concentration in Guangdong was about 30 µg·m-3, which meets the national secondary ambient air quality standard.

Evidence of preserved collagen in an Early Jurassic sauropodomorph dinosaur revealed by synchrotron FTIR microspectroscopy.

Fossilized organic remains are important sources of information because they provide a unique form of biological and evolutionary information, and have the long-term potential for genomic explorations. Here we report evidence of protein preservation in a terrestrial vertebrate found inside the vascular canals of a rib of a 195-million-year-old sauropodomorph dinosaur, where blood vessels and nerves would normally have been present in the living organism. The in situ synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectra exhibit the characteristic infrared absorption bands for amide A and B, amide I, II and III of collagen. Aggregated haematite particles (α-Fe2O3) about 6∼8 µm in diameter are also identified inside the vascular canals using confocal Raman microscopy, where the organic remains were preserved. We propose that these particles likely had a crucial role in the preservation of the proteins, and may be remnants partially contributed from haemoglobin and other iron-rich proteins from the original blood.

A p-i-n junction diode based on locally doped carbon nanotube network.

A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field in the SWNTs. The results showed that the forward current and the rectification ratio of the diode increased as the doping degree increased. The forward current of the device could also be increased by decreasing the channel length. A high-performance p-i-n junction diode with a high rectification ratio (~10(4)), large forward current (~12.2 µA) and low reverse saturated current (~1.8 nA) was achieved with the OA and PEI doping time of 5 h and 18 h for a channel length of ~6 µm.

Carbon nanotube intramolecular p-i-n junction diodes with symmetric and asymmetric contacts.

A p-i-n junction diode based on the selectively doped single-walled carbon nanotube (SWCNT) had been investigated, in which two opposite ends of individual SWCNT channel were doped into the p- and n-type SWCNT respectively while the middle segment of SWCNT was kept as the intrinsic. The symmetric and asymmetric contacts were used to fabricate the p-i-n junction diodes respectively and studied the effect of the contact on the device characteristics. It was shown that a low reverse saturation current of ~20 pA could be achieved by these both diodes. We found that the use of the asymmetric contact can effectively improve the performance of the p-i-n diode, with the rectification ratio enhanced from ~10(2) for the device with the Au/Au symmetric contact to >10(3) for the one with the Pd/Al asymmetric contact. The improvement of the device performance by the asymmetric-contact structure was attributed to the decrease of the effective Schottky-barrier height at the contacts under forward bias, increasing the forward current of the diode. The p-i-n diode with asymmetric contact also had a higher rectification ratio than its counterpart before doping the SWCNT channel, which is because that the p-i-n junction in the device decreased the reverse saturated current.

The development of ecological impact assessment in China.

The balance between economic development and ecological conservation in China has become a critical issue in recent decades. Ecological impact assessment (EcoIA) was established beginning in the 1980s as a component of environmental impact assessment (EIA) that focuses specifically on human-related changes in ecosystem structure and function. EcoIA has since been widely applied throughout the country with continuous refinements in theory and practice. As compared to EIA, EcoIA is often performed at a larger scale in the long-term, and thus requires more advanced tools and techniques to quantify and assess. This paper reviews the development of EcoIA over the past 30years in China, with specific consideration given to refinements in legislation and methodology. Three stages in the development of EcoIA in China are identified, along with their achievements and limitations. Supplementing this qualitative analysis, the paper also provides a quantitative bibliometrics review of academic publications concerning EcoIA in China over the three identified stages. Lastly, general trends in the development of EcoIA are summarized with the aim of conveying potential future trajectories. This review is intended to introduce the EcoIA system to scholars interested in the growing field of environmental management in China.

Assessing Long-Term Trend of Particulate Matter Pollution in the Pearl River Delta Region Using Satellite Remote Sensing.

Serious particulate matter (PM) pollution problems in many polluted regions of China have been frequently reported in recent years. Long-term exposure to ambient PM pollution is significantly associated with adverse health effects. Characterizing the long-term trends and variation in PM pollution is a basic requirement for evaluating long-term exposure and for guiding future policies to reduce the effects of air pollution on health. However, long-term, ground-based PM measurements are only available at a few fixed stations. In this study, an algorithm is developed and validated to estimate PM concentrations based on the satellite atmospheric optical depth with 1 km spatial resolution. The long-term trends of PM10 concentrations in the entire Pearl River Delta (PRD) region and different cities are quantified and discussed. From 2001 to 2013, the PM10 pollution of the entire PRD region was dominated by a decreasing trend of -0.15 ± 0.23 µg/m(3)·yr. This decreasing PM10 trend was apparent over 75% of the PRD area, with the most significant decreases observed in the center of the region. However, the remaining 25%, mostly located in the outskirts of the region, showed an increasing PM10 trend. This overall decreasing trend indicates the effectiveness of the control measures applied in the past decade for the primary pollutants.

Human acellular cartilage matrix powders as a biological scaffold for cartilage tissue engineering with synovium-derived mesenchymal stem cells.

In our previous study, we found that cartilage fragments from osteoarthritic knee promoted chondrogenesis of mesenchymal stem cells. In this study, we further transformed the cartilage tissues into acellular cartilage matrix (ACM) and explored the feasibility of using ACM as a biological scaffold. Nonworn parts of cartilage tissues were obtained during total knee arthroplasty (TKA) surgery and were successfully fabricated into ACM powders. The ACM powders and human synovium-derived mesenchymal stem cells (SMSCs) were mixed into collagen gel for in vitro culture. Histological results showed a synergistic effect of ACM powders and chondrogenic growth factors in the formation of engineered cartilage. The findings of real-time polymerase chain reaction (PCR) suggested that ACM powders had the potential of promoting type II collagen gene expression in the growth factors-absent environment. Moreover, with growth factors induction, the ACM powders could reduce the hypertrophy in chondrogenesis of SMSCs. In summary, ACM powders could serve as a functional scaffold that benefited the chondrogenesis of SMSCs for cartilage tissue engineering.

Cartilage fragments from osteoarthritic knee promote chondrogenesis of mesenchymal stem cells without exogenous growth factor induction.

Extracellular matrix (ECM) is thought to participate significantly in guiding the differentiation process of mesenchymal stem cells (MSCs). In this study, we hypothesized that cartilage fragments from osteoarthritic knee could promote chondrogenesis of MSCs. Nonworn parts of cartilage tissues were obtained during total knee arthroplasty (TKA) surgery. Cartilage fragments and MSCs were wrapped into fibrin glue; and the constructs were implanted subcutaneously into nude mice. Histological analysis showed neocartilage-like structure with positive Alcian blue staining in the cartilage fragment-fibrin-MSC constructs. However, constructs with only MSCs in fibrin showed condensed appearance like MSCs in the pellet culture. Gene expression of type II collagen in the constructs with 60 mg cartilage fragments were significantly elevated after 4 weeks of implantation. Conversely, the constructs without cartilage fragments failed to express type II collagen, which indicated MSCs did not differentiate into a chondrogenic lineage. In conclusion, we demonstrated the effect of cartilage fragments from osteoarthritic knee in promoting chondrogenic differentiation of MSCs. This may be a favorable strategy for MSC chondrogenesis without exogenous growth factor induction.