A DiffeRential Evolution Adaptive Metropolis (DREAM)-based inverse model for continuous release source identification in river pollution incidents: Quantitative evaluation and sensitivity analysis.

The identification of continuous pollution sources for rivers is of great concern for emergency response. Most studies focused on instantaneous river pollution sources and associated incidents. There is a dire need to address continuous pollution sources, as pollutant discharge may impose a major impact on the water ecosystem. Therefore, in this study, a novel inverse model is proposed to identify the continuous point sources in river pollution incidents that would estimate the source strength, location, release time, and spill time. The proposed inverse model combines the advanced DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm and the forward transport advection-dispersion equation to infer the posterior probability distribution of source parameters for quantifying uncertainties. In addition, the performance of the DREAM-based model is compared with those of the Metropolis-Hastings (MH)-based and genetic algorithm (GA)-based models. The results show that the DREAM-based model performs accurately for both the hypothetical and the field tracer cases. The comparative analysis shows that the DREAM-based model performs better in saving computation time, improving the accuracy of results, and reconstructing pollutant concentrations. Observation errors significantly influence the accuracy of the identification results from the DREAM-based model. In addition, a comprehensive sensitivity analysis of the DREAM-based model is conducted. The identification results from the DREAM-based model are sensitive to the dispersion coefficient and river velocity. The accuracy of the inverse model could be improved by increasing the monitoring number and by monitoring locations closer to the spill site. The findings of this study can improve decision-making during emergency responses to sudden river pollution incidents.

Spatial and temporal variability and risk assessment of organophosphate esters in seawater and sediments of the Yangtze River estuary.

Organophosphate esters (OPEs) as substitutes for PBDEs have been widely detected in the marine environment, while little is known about the pollution characteristics and variation of OPEs in estuarine environments with complex hydrodynamic conditions and land-based input. Yangtze River Estuary (YRE) is a typical highly urbanized and industrialized estuary, with a complex hydrological environment and geochemical behavior. This study found that the concentrations of OPEs in both seawater and sediments in the YRE were higher in spring than in summer. Alkyl OPEs were the first contributor, with TnBP and TiBP as the main components, where the contribution of alkyl OPEs had exceeded 75 % in both seawater and sediments in spring, and 60 % in summer seawater, and even 80 % in sediments. In spring, OPEs peaked in the central to southern region near the YRE. In summer, OPEs were mainly concentrated in the southern branch waterway and southern nearshore area of the YRE and showed a decreasing trend to the northeast. The OPEs in the sediments were mainly concentrated in the Yangtze River Mud Area (YREMA) and the Zhe-Min Coastal Mud Area (ZMCMA). Based on the fugacity model and principal component analysis, sediments could be released into the aquatic environment as an endogenous source, and exogenous sources were mainly municipal and industrial sewage discharge sources, urban and marine traffic discharge sources, and atmospheric deposition sources. The ecological risk analysis showed that the Σ14OPEs had exhibited a low to moderate ecological risk in the southern branch waterway and the south-central region offshore.

Designing of a functional paper-tip substrate for sensitive surface-enhanced Raman spectroscopy (SERS) detection.

A simple and flexible fabrication method of paper SERS substrate was developed by nanoparticles (NPs) droplet self-assembly at the paper tip with a temperature gradient (PTTG). We turned the drawback of the coffee ring effect into an effective way of preparing paper SERS substrate. When the NPs droplets were continuously dripped onto the PTTG, NPs were densely and uniformly distributed at the paper-tip front based on the combination of gravity and the coffee ring effect, which could achieve 91.2-fold improvement of SERS performance compared to a flat filter paper. Meanwhile, the analytes could also be enriched at the paper-tip front, which could achieve 9.3-fold signal enhancement compared to the paper-tip tail. Thus, the PTTG realized an excellent signal amplification for SERS detection. The paper-tip SERS substrate combined with a portable Raman spectrometer yielded an excellent analytical enhancement factor of 1.15 × 105 with the detection limit of 10 nM Rhodamine 6G (R6G). The whole fabrication procedure was completed within 2 h, and the paper-tip substrate showed a satisfactory substrate-to-substrate reproducibility with a relative standard deviation (RSD) of 5.13% (n = 10). It was successfully applied for quantitatively detecting real samples of oxytetracycline and malachite green with recoveries of 83.84-105.25% (n = 3). Meanwhile, we further evaluated the SERS performance of the PTTG using a laboratory-based Raman spectrometer, and it could realize the detection as low as 10 pM R6G. The proposed paper-tip substrate would offer a promising potential application for the on-site SERS analysis of food safety and environmental health.

Bent-Capillary-Centrifugal-Driven Monodisperse Droplet Generator with Its Application for Digital LAMP Assay.

We developed a bent-capillary-centrifugal-driven (BCCD) monodisperse droplet generator, which could achieve a perfect combination of driving and segmentation for the dispersed phase only using a rotating bent capillary immersed in the continuous phase (mineral oil). The sample could flow continuously to the bent-capillary outlet to form the droplet precursors, which were segmented into homogeneous droplets in the continuous phase. Through the investigation of influence factors on droplet size and stability, we found that the droplet size could be conveniently controlled by the rotational speed of the bent capillary. The droplet volumes could be adjusted with the range from 34 pL to 1 µL, and the coefficient variations (CVs) were less than 3%. Meanwhile, the BCCD droplet generator could realize the controllable droplet output with a high-efficiency sample utilization of 99.75 ± 1.15%, which offered a significant advantage in reducing the waste of precious samples in the droplet generation process. We validated this system with a digital loop-mediated isothermal amplification (dLAMP) assay for the absolute quantification of Mycobacterium tuberculosis complex nucleic acids. The results demonstrated that the BCCD droplet generator was easy to build, was of low cost, and was convenient to operate, as well as avoided sample loss and cross-contamination by coupling with a 96-well plate. Overall, the present platform, as a simple chip-free droplet generator, will provide an especially valuable droplet generation solution for biochemical applications based on droplets.

Target-induced gold nanoparticles colorimetric sensing coupled with aptamer for rapid and high-sensitivity detecting kanamycin.

Herein we report a novel colorimetric sensing strategy for the detection of kanamycin (kana) based on target-induced gold nanoparticles (AuNPs) coupled with aptamers. Aptamer-functionalized AuNPs, as the colorimetric probe, showed a distinct red shift with addition of kana, which avoiding the tedious and unnecessary additive-induced process. To study the interaction between kana and AuNPs and the effects of the specific aptamer adsorption, a series of experiments including UV-vis absorbance and surface enhanced Raman spectroscopy (SERS) were performed. Based on the results, a new alternative view is proposed that kana can directly induce the aggregation of aptamer-wrapped AuNPs, attributed to the co-adsorption of kana and aptamer on the surface of AuNPs. The proposed colorimetric sensing exhibited high selectivity and sensitivity for kanamycin assay with a wide linear range from 10.0 nM to 4.0 µM, and the limit of detection (LOD) reached 4.0 nM. Moreover, the whole detection process could be completed within 5 min, and it also achieved excellent performance in real samples detection with recoveries in the range of 86.22-109.89%. The results indicate that target-induced AuNPs colorimetric sensing coupled with aptamers for the direct detection of kana is simple, rapid and high-sensitivity, has the promising potential applications in the fields of food safety and environmental monitoring.

Interactions of microplastics with organic, inorganic and bio-pollutants and the ecotoxicological effects on terrestrial and aquatic organisms.

As emerging contaminants, microplastics (MPs) have attracted global attention. They are a potential risk to organisms, ecosystems and human health. MPs are characterized by small particle sizes, weak photodegradability, and are good environmental carriers. They can physically adsorb or chemically react with organic, inorganic and bio-pollutants to generate complex binary pollutants or change the environmental behaviors of these pollutants. We systematically reviewed the following aspects of MPs: (i) Adsorption of heavy metals and organic pollutants by MPs and the key environmental factors affecting adsorption behaviors; (ii) Enrichment and release of antibiotic resistance genes (ARGs) on MPs and the effects of MPs on ARG migration in the environment; (iii) Formation of "plastisphere" and interactions between MPs and microorganisms; (iv) Ecotoxicological effects of MPs and their co-exposures with other pollutants. Finally, scientific knowledge gaps and future research areas on MPs are summarized, including standardization of study methodologies, ecological effects and human health risks of MPs and their combination with other pollutants.

A new method for quantifying the value of ecological environment damage caused by illegal fishing: A case study.

Illegal fishing may trigger structural disruption of the food chain and even damage the entire marine ecosystem. This paper proposes a new method for quantifying the value of eco-environment damage caused by illegal fishing; as an example, we used an illegal fishing case of anchovies in the vicinity of the Yellow River Delta National Nature Reserve. Based on the data from the field investigation and literature, we estimated the number and age distribution of illegally harvested anchovies. Additionally, the potential number of the offspring was calculated according to the potential number and survival rate of anchovy eggs. Due to the unavailability of commercial anchovy fries, "alternative stock enhancement" was recommended to restore the damaged eco-environment. Notably, the alternative species should have similar economic value, status in the food chain, and living areas to anchovies. Eventually, we selected Liza haematocheilus as the alternative species and calculated the total eco-environment recovery cost.

Saponin 1 induces apoptosis and suppresses NF-κB-mediated survival signaling in glioblastoma multiforme (GBM).

Saponin 1 is a triterpeniod saponin extracted from Anemone taipaiensis, a traditional Chinese medicine against rheumatism and phlebitis. It has also been shown to exhibit significant anti-tumor activity against human leukemia (HL-60 cells) and human hepatocellular carcinoma (Hep-G2 cells). Herein we investigated the effect of saponin 1 in human glioblastoma multiforme (GBM) U251MG and U87MG cells. Saponin 1 induced significant growth inhibition in both glioblastoma cell lines, with a 50% inhibitory concentration at 24 h of 7.4 µg/ml in U251MG cells and 8.6 µg/ml in U87MG cells, respectively. Nuclear fluorescent staining and electron microscopy showed that saponin 1 caused characteristic apoptotic morphological changes in the GBM cell lines. Saponin 1-induced apoptosis was also verified by DNA ladder electrophoresis and flow cytometry. Additionally, immunocytochemistry and western blotting analyses revealed a time-dependent decrease in the expression and nuclear location of NF-κB following saponin 1 treatment. Western blotting data indicated a significant decreased expression of inhibitors of apoptosis (IAP) family members,(e.g., survivin and XIAP) by saponin 1. Moreover, saponin 1 caused a decrease in the Bcl-2/Bax ratio and initiated apoptosis by activating caspase-9 and caspase-3 in the GBM cell lines. These findings indicate that saponin 1 inhibits cell growth of GBM cells at least partially by inducing apoptosis and inhibiting survival signaling mediated by NF-κB. In addition, in vivo study also demonstrated an obvious inhibition of saponin 1 treatment on the tumor growth of U251MG and U87MG cells-produced xenograft tumors in nude mice. Given the minimal toxicities of saponin 1 in non-neoplastic astrocytes, our results suggest that saponin 1 exhibits significant in vitro and in vivo anti-tumor efficacy and merits further investigation as a potential therapeutic agent for GBM.

Saponin B, a novel cytostatic compound purified from Anemone taipaiensis, induces apoptosis in a human glioblastoma cell line.

Glioblastoma multiforme (GBM) is one of the most common malignant brain tumors. Saponin B, a novel compound isolated from the medicinal plant, Anemone taipaiensis, has been found to have a strong time- and dose-dependent cytostatic effect on human glioma cells and to suppress the growth of U87MG GBM cells. In this study, we investigated whether saponin B induces the apoptosis of glioblastoma cells and examined the underlying mechanism(s) of action of saponin B. Saponin B significantly suppressed U87MG cell proliferation. Flow cytometric analysis of DNA in the U87MG cells confirmed that saponin B blocked the cell cycle at the S phase. Furthermore, treatment of the U87MG cells with saponin B induced chromatin condensation and led to the formation of apoptotic bodies, as observed under a fluorescence microscope, and Annexin V/PI assay further suggested that phosphatidylserine (PS) externalization was apparent at higher drug concentrations. Treatment with saponin B activated the receptor-mediated pathway of apoptosis, as western blot analysis revealed the activation of Fas-l. Saponin B increased the Bax and caspase-3 ratio and decreased the protein expression of Bcl-2. The results from the present study demonstrate that the novel compound, saponin B, effectively induces the apoptosis of GBM cells and inhibits glioma cell growth and survival. Therefore, saponin B may be a potential candidate for the development of novel cancer therapeutics with antitumor activity against gliomas.

Plexin-B1: a potential diagnostic biomarker for glioma and a future target for glioma immunotherapy.

Gliomas are the most common tumors in the central nervous system. Plexin-B1 is abundantly expressed in the nervous system as an axonal guidance molecule during neuronal development. However, the correlation between its expression and the clinical characteristics of gliomas, and its therapeutic significance, remain largely unexplored. In this study, we detected the expression of Plexin-B1 in clinical glioma tissue samples. Plexin-B1 was highly expressed in the cytoplasm and on the membrane of glioma tissues, while only trace levels of Plexin-B1 were present in normal brain tissue. The expression level of Plexin-B1 in glioma tissue was associated with the pathological grade of the glioma. In addition, we used flow cytometry to analyze the expression of Plexin-B1 in glioma cell lines and its ligand, semaphorin 4D (Sema4D), in natural killer (NK) cell lines. Cytotoxicity assays showed cytolysis of the U251 glioma cell line by the NK cell line, NK92, and this was markedly downregulated when the neutralizing antibody to Plexin-B1 was added. This study demonstrates that Plexin-B1 could be used as a diagnostic biomarker, and also suggests that it may be involved in the cytotoxicity of NK cells to glioma cells. Plexin-B1 could be a useful future target for glioma immunotherapy.

[Preliminary study on identification of oil products using laser-Raman fingerprint spectrum].

Laser-Raman spectroscopy technology was used for measuring and analyzing properties of oil products. Through comparing with the Raman shifts and relative Raman intensity ratios of the main fingerprint peaks, different kinds of oil products were identified successfully. Furthermore, the Raman spectra of the same type of petroleum products obtained from different private gas stations were measured and the petroleum qualities were detected. The favorable results were obtained in both oil identification and quality test. The present work provides a feasible method for quick, sensitive and nondestructive identification of oil products.

[The study of fluorescence spectrum using ultraviolet-laser for several typical oil pollutants].

In order to realize the fast and non-contact detection of oil pollution in costal zone, the ultraviolet laser was used as the exciting source, a system used for oil pollution based on laser-induced-fluorescence (LIF) technology was established. The fluorescence spectra of several oil samples were measured through this system. The measurement results show that there are obvious differences among the fluorescence spectra of these samples, which can be used as a reference for oil pollution classification and recognition.

[Autogenous platelet-rich plasma gel with acellular xenogeneic dermal matrix for treatment of deep II degree burns].

OBJECTIVE: To investigate the effectiveness of autogenous platelet-rich plasma (PRP) gel with acellular xenogeneic dermal matrix in the treatment of deep II degree burns. METHODS: From January 2007 to December 2009, 30 cases of deep II degree burns were treated. There were 19 males and 11 females with an average age of 42.5 years (range, 32-57 years). The burn area was 10% to 48% of total body surface area. The time from burn to hospitalization was 30 minutes to 8 hours. All patients were treated with tangential excision surgery, one side of the wounds were covered with autogenous PRP gel and acellular xenogeneic dermal matrix (PRP group), the other side of the wounds were covered with acellular xenogeneic dermal matrix only (control group). The healing rate, healing time, infection condition, and scar formation were observed. RESULTS: At 7 days after operation, the infection rate in PRP group (6.7%, 2/30) was significantly lower than that in control group (16.7%, 5/30, P < 0.05). The healing times were (18 +/- 4) days and (22 +/- 4) days respectively in PRP group and control group, showing significant difference (P < 0.05). The healing rates at 14 days and 21 days were 75% +/- 7% and 88% +/- 5% in PRP group, were 62% +/- 15% and 73% +/- 7% in control group, showing significant difference (P < 0.05). RPR group was superior to control group in elasticity, color, appearance, softness, scar formation, and healing quality. CONCLUSION: Autogenous PRP gel with acellular xenogeneic dermal matrix can accelerate the wound healing of deep II degree burns as well as alleviate the scar proliferation.

[Application of damage control surgery strategy in treatment of burn-trauma combined injury].

OBJECTIVE: To explore the application of damage control surgery (DCS) strategy in the treatment of severe burn-trauma combined injury. METHODS: From January 2004 to December 2009, 28 patients with severe burn-trauma combined injury received salvage treatment according to DCS, including 12 cases of burn combining injury at 2 sites, 6 cases of burn combining injury at 3 sites, and 10 cases of burn combining injury at 4 sites or above. There were 18 males and 10 females with a median age of 39.5 years (range, 8-56 years). The burn area was 15% to 56% of total body surface area. The injury severity score a (ISS) was 25 to 56, and the traumatic index was 17 to 24. Lethal triad syndrome occurred in all patients. Of them, 16 cases were on admission immediately after first-aid, and 12 cases were transferred from other hospitals. The time from injury to hospitalization was 20 minutes to 36 hours. All patients were treated by immediate fluid resuscitation and emergent operation to control hemorrhage and contaminations. Biological dressings were used to seal the wounds provisionally. The systemic therapy was carried out as soon as the vital signs of the patients became stable. RESULTS: In 26 survivors, 23 achieved wound healing by first intention, 3 had a little residual wound at discharge. The hospitalization days were 31 to 398 days (62 days on average). However, 1 patient died of multiple organ failure, another 1 patient died of severe cerebral trauma with refractory shock. CONCLUSION: The DCS strategy is effective in reducing mortality of patients with severe burn-trauma combined injury.

[Classification of oils by attenuated total reflectance-Fourier transform infrared spectrometry combined with pattern recognition techniques].

In the present work, the combination of attenuated total reflectance-Fourier transform infrared spectrometry (ATR-FTIR) and pattern recognition, including principal components analysis (PCA) and hierarchical cluster analysis (HCA), is used as a fast and convenient analytical tool to classify oil samples. Twenty five samples including crude oils and fuel oils with different total contents of n-alkanes were analyzed. It was found that multiplicative scatter correction (MSC) and continuous wavelet transform (CWT) as a pretreatment method could improve the classification results of pattern recognition. The classification results were proved to be in agreement with the origin of the oil samples. The oils with high content of n-alkanes and those with low content were classified clearly by this developed method, but it still had some constraint to differentiating oils with little difference. The present work provides a feasible method for quick classification of oils, which can be used for the initial identification of spill oils and afford useful information for the further identification of the oils.

[Identification of crude oils in Bohai Sea by polycyclic aromatic hydrocarbon fingerprinting].

Crude oils from different sources have quite different polycyclic aromatic hydrocarbon (PAH) distributions. Also, many PAH compounds are more resistant to weathering than their saturated counterparts (n-alkanes and isoprenoids) and volatile alkylbenzene compounds, thus PAils become one of the most valuable classes of hydrocarbons for oil identification using fingerprinting. A reliable, effective, and accurate gas chromatography/mass spectrometry (GC/MS) method for the differentiation and source identification of crude oils by the use of PAH compounds is described. PAll components of 6 crude oil samples from 5 different platforms in 4 different oil fields in Bohal Sea were analyzed by GC/MS. Using different methods, such as the comparisons of original fingerprinting, characteristic information, and diagnostic ratios of PAHs, 6 crude oil samples were identified completely, which showed distinctive characteristics of the same platform oils. Although distinction was diminutive, it can still be identified by GC/MS. PAHs could be used in weathering check of spilled oils in identification and to ensure the correctness of the identification.