Revealing the Molecular Weight Effect on Highly Efficient Polythiophene Solar Cells.

Polythiophenes (PTs) are promising electron donors in organic solar cells (OSCs) due to their simple structures and excellent synthetic scalability. Benefiting from the rational molecular design, the power conversion efficiency (PCE) of PT solar cells has been greatly improved. Herein, five batches of the champion PT (P5TCN-F25) with molecular weights ranging from 30 to 87 kg mol-1 were prepared, and the effect of the molecular weight on the blend film morphology and photovoltaic performance of PT solar cells was systematically investigated. The results showed that the PCEs of the devices improved first and then maintained a high value with the increase of molecular weight, and the highest PCE of 16.7% in binary PT solar cells was obtained. Further characterizations revealed that the promotion in photovoltaic performance mainly comes from finer phase separation structures and more compact molecular packing in the blend film. The best device stabilities were also achieved by polymers with high molecular weights. Overall, this study highlights the importance of optimizing the molecular weight for PTs and offers directions to further improve the PCE of PT solar cells.

Genotoxicity of chloroacetamide herbicides and their metabolites in vitro and in vivo.

The toxicity of chloroacetamide herbicide in embryo development remains unclear. Acetochlor (AC) is a chloroacetamide that metabolizes into 2­ethyl­6­methyl-2-chloroacetanilide (CMEPA) and 6­ethyl­o­toluidine (MEA). The present study determined the potential effect of AC and its metabolites on embryo development. Both HepG2 cells and zebrafish embryos were exposed to AC, CMEPA and MEA in the presence or absence of co­treatment with anti­reactive oxygen species (ROS) reagent N­acetylcysteine. The generation of ROS, levels of superoxide dismutase (SOD) and glutathione (GSH) in HepG2 cells and lactate dehydrogenase (LDH) leakage from HepG2 cells were investigated. The effects of AC, CMEPA and MEA on DNA breakage, MAPK/ERK pathway activity, viability and apoptosis of HepG2 cells were examined by comet assay, western blotting, MTT assay and flow cytometry, respectively. Levels of LDH, SOD and GSH in zebrafish embryos exposed to AC, CMEPA and MEA were measured. The hatching and survival rates of zebrafish embryos exposed to AC, CMEPA and MEA, were determined, and apoptosis of hatched fish was investigated using acridine orange staining. The present data showed AC, CMEPA and MEA induced generation of ROS and decreased levels of SOD and GSH in HepG2 cells, which in turn promoted DNA breakage and LDH leakage from cells, ultimately inhibiting cell viability and inducing apoptosis, as well as phosphorylation of JNK and P38. However, co­treatment with N­acetylcysteine alleviated the pro­apoptosis effect of AC and its metabolites. Moreover, exposure to AC, CMEPA and MEA lead to toxicity of zebrafish embryos with decreased SOD and GSH and increased LDH levels and cell apoptosis, ultimately decreasing the hatching and survival rates of zebrafish, all of which was attenuated by treatment with N­acetylcysteine. Therefore, AC and its metabolites (CMEPA and MEA) showed cytotoxicity and embryo development toxicity.

Efficacy and safety of endostatin in combination with chemotherapy in small cell lung cancer: a phase 2 single-arm multicenter open-label trial.

BACKGROUND: Small-cell lung cancer (SCLC) is a type of lung cancer with high invasiveness and poor prognosis. Although SCLC is effective for initial treatment, the vast majority of patients will relapse, the efficacy of posterior line therapy is limited, and there is a lack of effective treatment. At the same time, in the past 30 years, there has been little progress in first-line treatment. With the progress of antiangiogenic therapy, whether it can be used in the treatment of SCLC is worth exploring. Therefore, a single-arm multicenter clinical study was conducted on the efficacy, optimization, and safety of endostatin combined chemotherapy in SCLC. METHODS: This study is a prospective non-blind single-arm multicenter study. From January 2016 to July 2019, a total of 22 patients with histologically diagnosed SCLC were enrolled in three centers. The treatment regimen was as follows: continuous intravenous pump infusion of endostatin (90 mg) for 72 hours, 3 days before chemotherapy, and continuous pump infusion of endostatin (120 mg) for 96 hours the next day following the infusion of chemotherapeutic drugs; the chemotherapy regimen was administered with standard platinum combined with etoposide once every 21 days. After six cycles, endostatin maintenance therapy was used until the disease progressed or intolerable adverse reactions occurred. The therapeutic effect was evaluated by imaging and oncology markers every two cycles, and the adverse reactions, tumor progression time, and patient survival time were recorded. RESULTS: Among the 21 patients analyzed, the median progression-free survival (PFS) was 8.0 months, the median overall survival (OS) was 13.6 months, the objective effective rate (ORR) was 61.9%, and the disease control rate (DCR) was 95.2%. All patients tolerated the treatment. The main adverse reactions were myelosuppression, albuminuria, nausea, and vomiting. The incidence of grade 3 or 4 adverse reactions was 7.2%, which could be relieved by symptomatic support treatment. There were no treatment-related deaths. CONCLUSIONS: Endostatin combined with platinum-etoposide is safe and effective in the treatment of SCLC.

A new carbon emission reduction mechanism: Carbon Generalized System of Preferences (CGSP).

Countries throughout the whole world, including China, are working together to curb the greenhouse effect, but the effects seem very limited in spite of the fact that various low-carbon development strategies have been adopted, particularly in industrial enterprises. Therefore, carbon emissions caused by the public should be taken seriously, and the public should be encouraged to engage in behavior that limits carbon emissions. Therefore, this article introduces a new incentive mechanism called the Carbon Generalized System of Preferences (CGSP), which was first introduced in Guangdong Province, China. It is believed that this new mechanism matches the role of leadership in Guangdong in the urbanization and economic development of China by addressing the small sources of greenhouse gases (GHGs) and by issuing carbon coins. Compared with Chinese Certified Emission Reduction (CCER), the development scope, management level, and novel criteria of CGSP are very different but relatively easy for the public to accept. The CGSP shows that the network platform, reduced carbon emissions, and urban pilots are all compatible with the goals of the nation and city, and they promote the CGSP in different ways. Because of its consistency with ecological civilization in China, the prospect of the CGSP is bright; however, there are some challenges, such as policy and economic factors, combined with pollution control.

Simultaneous determination of lactic acid and pyruvic acid in tissue and cell culture media by gas chromatography after in situ derivatization-ultrasound-assisted emulsification microextraction.

Lactic acid and pyruvic acid are important metabolites in the tricarboxylic acid cycle that can reflect the cytoplasmic redox state and mitochondrial respiratory chain function. The combination of these acids is considered as a screening index for mitochondrial disorders. Due to their biological effects, a derivatization method was developed to simultaneously detect pyruvic acid and lactic acid in tissue and cell culture media using gas chromatography. In this work, the combined derivatization method with methoxyamine hydrochloride and isobutyl chloroformate was first proposed. To improve the efficiency of derivatization, in situ derivatization-ultrasound-assisted emulsification microextraction (USAEME) was used in this study. After optimizing the volume of reagents and reaction times, good linearity values were obtained from 50 to 1000 µmol/L and 1 to 100 µmol/L for lactic acid and pyruvic acid, respectively. The limits of detection (LODs) were 0.12 µmol/L for lactic acid and 0.29 µmol/L for pyruvic acid. The recoveries of the two analytes were between 93.60 and 102.80%, and the precisions were less than 6.20%. This method was successfully applied to quantify pyruvic acid and lactic acid in the animal and cellular hypoxia models which provided an auxiliary means for the diagnosis of mitochondrial diseases. Graphical abstract ᅟ.

Author Correction: Cytotoxicity of Aconitum alkaloid and its interaction with calf thymus DNA by multi-spectroscopic techniques.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Derivatization method for the quantification of lactic acid in cell culture media via gas chromatography and applications in the study of cell glycometabolism.

Lactic acid represents an important metabolite that reflects mitochondria function and may further serve as energy source for cancer cells. In light of this physiological and pathological significance, we developed a novel and sensitive gas chromatography method to detect lactic acid in cell culture media. Here, ethyl chloroformate was selected as derivative reagent and the derivatization process was further optimized in terms of number of reagents and reaction time as well as extraction reagents. Under optimal conditions, good linearity was achieved in the tested calibration range. The limit of detection (LOD) was determined to be 0.67 µmol/L, the recovery rates were 99.6%-106% and the precision rate RSD was <5.49%. Furthermore, this method has been applied to quantify the secretion of lactic acid in cells exposed to mono­2­ethylhexyl phthalate at different doses and in cancer cells over time. Taken in concert, our method proved to be both sensitive and reliable and may be applied for studies on mitochondrial function and cell glycolysis conditions.

Determination of organophosphorus flame retardants in fish by freezing-lipid precipitation, solid-phase extraction and gas chromatography-mass spectrometry.

An analytical method has been developed for measuring 12 organophosphorus flame retardants (PFRs) in fish tissue samples. After the Soxhlet extraction of PFRs with dichloromethane. The experimental parameters of the clean-up were systematically optimized. Methanol was found to be a more effective solvent than acetonitrile used in freezing-lipid precipitation. Methanol (5%) in ultrapure water, was finally selected to perform solid-phase extraction (SPE, Oasis HLB cartridge), with mean lipid removal efficiency of 94% after freezing-lipid precipitation. Further purification followed by 200mg of Z-Sep and C18 dispersant to eliminate the remaining interferences. Quantification was performed using gas chromatography-mass spectrometry in selective ion monitoring mode. The recovery, precision, and the method detection limits (MDLs) were verified by spiking experiments. All chemicals except triethyl phosphate (TEP) showed satisfactory recoveries in the range of 73-107% and 56-108% in the spiked blanks samples and spiked fish tissue samples, respectively. MDLs for PFRs in the biological samples ranged from 0.004 to 0.059ng/g. The proposed method successfully applied to the determination of PFRs in real fish samples with recoveries of four internal standards varying from 75 to 97%. The results demonstrated that the proposed method is highly effective for analyzing PFRs in fish samples.

Cytotoxicity of Aconitum alkaloid and its interaction with calf thymus DNA by multi-spectroscopic techniques.

The cytotoxicities of three aconitum alkaloids- aconitine, hypaconitine and mesaconitine, and their abilities to bind DNA have been explored. Rat myocardial cells H9c2 were treated with aconitum alkaloids and assessed the cytotoxicities by using MTT assay and flow cytometry. Apoptosis was evidenced by the results of the annexin V/propidium iodide (PI) assay. Aconitine was found to be the most toxic in rat myocardial cells H9c2 in three aconitum alkaloids. At the same time, DNA adducts were isolated and then analyzed by UV-Vis spectroscopy after exposure to alkaloids, which indicated that three alkaloids could bind to DNA in rat myocardial cells H9c2. Furthermore, their binding modes were investigated by UV-Visible, fluorescence, DNA melting studies and ionic strength effect. Results indicated that the interaction between three alkaloids and DNA were intercalation coupled with electrostatic effect. The estimated binding constants were between 4.83 × 105 M-1 to 9.85 × 105 M-1 for three alkaloids at 298 K.

Development of a derivatization method for the quantification of hydrogen sulfide and its application in vascular calcification rats.

Hydrogen sulfide (H2S) plays major functional and structural roles in diverse physiological functions and the pathogenesis of a variety of disorders in biological matrices. The significance of H2S has prompted the development of sensitive and selective methods to determine its concentration in biological samples. The fluorescent reagent monobromobimane (MBB) has been widely used to measure various thiol-containing species through alkylation. MBB may prevent the oxidation of sulfide and the reaction of sulfide with several different species (such as superoxide radicals, hydrogen peroxide and peroxynitrite). An isomers of MBB, 3-(bromomethyl)-2, 6, 7-trimethyl-1H, 5H-pyrazolo [1,2-a] pyrazole-1, 5-dione (MMB), is cheaper than MBB and its use in the analysis of H2S has not previously been reported. In the present study, we compared the derivatization reactions of hydrogen sulfide with MMB and MBB and developed a sensitive method to quantify H2S in blood. In our method, H2S was incubated in the dark with excess MMB in 0.1M Tris-HCl buffer (pH 10.1) at 50°C for 120min. 50µL aliquots of the derivatized product were analyzed using HPLC system with gradient elution of 0.1% (v/v) formic acid-acetonitrile. The limit of detection for the derivatized product was 0.03nmol/mL. The derivatization reaction was suitable for detecting low concentrations of H2S. The derivate product is stable over time, permitting batch storage and analysis.

Distribution of organophosphorus flame retardants in sediments from the Pearl River Delta in South China.

Twelve organophosphorus flame retardants (PFRs) were identified in the sediments and the sediment core collected from the rivers and the estuary in the Pearl River Delta, with the aim of investigating their spatial and vertical distributions. The concentrations of PFRs ranged from 8.3 to 470 ng/g dry weight with high levels of PFRs in the urban area and the e-waste recycling region. Generally, TPhP, TCPP, TEHP, TCEP, and TBEP were the dominant compounds of the PFRs, the composition of which varied across the different regions, reflecting the different sources of PFRs. In the estuary, the PFRs mainly derived from the Xijiang River and the Shunde sections. Increased concentrations of halogen-containing PFRs have been observed in the upper layers of the sediment core. Conversely, relatively high concentrations of halogen-free PFRs were observed in the lower layers of the sediment core, indicating different usage patterns or environmental behaviors between the halogen and the non-halogen PFRs in the study area.

Legacy and emerging halogenated organic pollutants in marine organisms from the Pearl River Estuary, South China.

A suite of legacy and emerging halogenated organic pollutants (HOPs) were measured in marine organisms (coastal fish and invertebrates) from the Pearl River Estuary, South China, to investigate the current contamination status after the Stockholm Convention was implemented in China. Dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were detected in all samples at concentrations of 54-1500, 16-700, and 0.56-59ng/g lipid weight, respectively. Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), 2,3,5,6-tetrabromo-p-xylene (pTBX), and pentabromotoluene (PBT) were also found at concentrations of ND (non-detectable) to 37ng/g lipid weight. The concentrations of these investigated contaminants in the present study were at moderate levels, as compared with those reported in other regions. Significant interspecies differences were found in the levels of DDTs, PCBs, PBDEs and the alternative halogenated flame retardants (AHFRs). DDTs were the predominant HOPs in those species and represented >50% of the total HOPs, followed by PCBs, PBDEs, and AHFRs. The total estimated daily intakes (EDIs) of DDTs, PCBs, PBDEs, and AHFRs were 28, 12, 1.0, and 0.18 (ng/kg)/d, respectively, via seafood consumption. These concentrations are not expected to pose health risks to humans.

An eight year (2005-2013) temporal trend of halogenated organic pollutants in fish from the Pearl River Estuary, South China.

Dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), 2,3,5,6-tetrabromo-p-xylene (pTBX) and pentabromotoluene (PBT) were measured in baby croaker (Collichthys lucidus) and mullet (Osteomugil ophuyseni) collected in 2005 and 2013 from the Pearl River Estuary. DDTs, HCHs, PCBs, and PBDEs were detected in two fish species at concentrations of 150-8100, 1.4-120, 22-560, 2.2-280 ng/g lipid wt., respectively. The levels of these chemicals were significantly lower in 2013 than in 2005. The compositions for DDTs, HCHs, and PBDEs in 2013 differed from those in 2005, indicating source changes between the two sampling periods. DP, pTBX and PBT were detected at concentrations of ND-130 ng/g lipid wt. No clear temporal trends were found for these contaminants. Overall, these results indicated the effectiveness of regulations and source controls in substantively reducing inputs of these contaminants to the Pearl River Estuary.

Cytotoxicity and DNA interaction of brucine and strychnine-Two alkaloids of semen strychni.

The cytotoxicities of the two alkaloids strychnine and brucine from the seed of Strychnos nux-vomica and their interaction with DNA were investigated. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrasolium bromide (MTT) assay was used to examine the growth inhibitory effects of these alkaloids on Vero cells after 24, 48 and 72h of incubation. The cytotoxicities of strychnine and brucine were found to be time- and concentration-dependent. Strychnine was determined to be more toxic to Vero cells than brucine. At the same time, the interactions of strychnine and brucine with DNA were investigated using neutral red (NR) dye as a probe by UV-vis spectroscopy, fluorescence spectroscopy, and an examination of the ionic strength effect, and the effects of alkaloids on DNA melting were also examined. The results indicated that a DNA-brucine mixture but not a DNA-strychnine mixture could be extracted from Vero cells after treatment with brucine and strychnine, respectively. Brucine competitively intercalated into the DNA double-helix causing fluorescence quenching of the DNA-NR system. UV absorption spectroscopy and the melting temperature (Tm) curve also provided evidence that brucine interacted with DNA through intercalation. Furthermore, the results of the ionic strength effect experiment suggested that electrostatic interactions between brucine and phosphate groups in the DNA backbone might also play an important role in the binding of brucine to DNA.