Unique Organic Crystal Skeleton Based on N-Phenyl-Carbazole Derivatives with Adjustable Room Temperature Phosphorescence and Highly Stable Inclusion Ability to Dichloromethane.

Monosubstituted 9-(2-bromophenyl)-carbazole (1Br1CZ) and disubstituted 9,9'-(2,4-dibromo-1,3-phenylene) bis(9H-carbazole) (2Br2CZ) are synthesized by introducing bromine into ortho-phenyl position of 9-phenyl-carbazole (PhCZ). The decomposition temperature with 5% mass loss and melting point of 2Br2CZ crystal are 360 and 230 °C. The highest occupied molecular orbital energy level of PhCZ is the highest, and that of 2Br2CZ is the lowest. The crystals of PhCZ, 1Br1CZ, and 2Br2CZ are monoclinic, orthorhombic, and triclinic system, which exhibit room temperature phosphorescence with lifetimes of 171.81, 37.15, and 28.77 ms, and their corresponding phosphorescence quantum yields are 0.83%, 0.16%, and 4.58%. It theoretically reveals that six triplet energy levels (T1-T6) exist under S1 in 2Br2CZ crystal, and the spin orbit coupling constants between S1 and Tn in 2Br2CZ are also greater than those in PhCZ and 1Br1CZ, which promotes the intersystem crossing. Meanwhile, through crystal structure and Hirshfeld surface analysis, the torsion angles between the carbazole unit of 2Br2CZ and the central phenyl group reached 85.28°. The 2Br2CZ crystal exhibits the richest intermolecular interactions. A cavity of 4.498 Å is formed within the crystal skeleton of 2Br2CZ, which can precisely fixe dichloromethane with a record-high desorption temperature over 145 °C.

From mec cassette to rdhA: a key Dehalobacter genomic neighborhood in a chloroform and dichloromethane-transforming microbial consortium.

Chloroform (CF) and dichloromethane (DCM) are groundwater contaminants of concern due to their high toxicity and inhibition of important biogeochemical processes such as methanogenesis. Anaerobic biotransformation of CF and DCM has been well documented but typically independently of one another. CF is the electron acceptor for certain organohalide-respiring bacteria that use reductive dehalogenases (RDases) to dechlorinate CF to DCM. In contrast, known DCM degraders use DCM as their electron donor, which is oxidized using a series of methyltransferases and associated proteins encoded by the mec cassette to facilitate the entry of DCM to the Wood-Ljungdahl pathway. The SC05 culture is an enrichment culture sold commercially for bioaugmentation, which transforms CF via DCM to CO2. This culture has the unique ability to dechlorinate CF to DCM using electron equivalents provided by the oxidation of DCM to CO2. Here, we use metagenomic and metaproteomic analyses to identify the functional genes involved in each of these transformations. Though 91 metagenome-assembled genomes were assembled, the genes for an RDase-named acdA-and a complete mec cassette were found to be encoded on a single contig belonging to Dehalobacter. AcdA and critical Mec proteins were also highly expressed by the culture. Heterologously expressed AcdA dechlorinated CF and other chloroalkanes but had 100-fold lower activity on DCM. Overall, the high expression of Mec proteins and the activity of AcdA suggest a Dehalobacter capable of dechlorination of CF to DCM and subsequent mineralization of DCM using the mec cassette. IMPORTANCE: Chloroform (CF) and dichloromethane (DCM) are regulated groundwater contaminants. A cost-effective approach to remove these pollutants from contaminated groundwater is to employ microbes that transform CF and DCM as part of their metabolism, thus depleting the contamination as the microbes continue to grow. In this work, we investigate bioaugmentation culture SC05, a mixed microbial consortium that effectively and simultaneously degrades both CF and DCM coupled to the growth of Dehalobacter. We identified the functional genes responsible for the transformation of CF and DCM in SC05. These genetic biomarkers provide a means to monitor the remediation process in the field.

Regulation of the co-transport of toluene and dichloromethane by adsorbed phase humic acid under different hydro-chemical conditions.

The transport behavior of combined organic pollutants in soil and groundwater has attracted significant attention in recent years. Research on the influence of humic acid (HA) on organic pollutant transport behavior mainly focuses on the study of the mobile phase HA, with less research on the adsorbed phase HA, especially regarding its interaction with combined pollutants. To enhance understanding of the regulation of co-transport and retention of combined pollutants by adsorbed phase HA, in this study, tests were conducted to investigate how toluene (TOL) and dichloromethane (DCM) are transported in the presence of adsorbed phase HA at different pH levels and ionic strengths. As the proportions of HA-coated sand increased, so did its adsorption capacity for TOL and DCM, which can be attributed to adsorbed phase HA providing more adsorption sites compared to plain sand, thereby reducing the transport potential of the pollutants. The presence of both TOL and DCM facilitated their mutual transportation due to competitive adsorption controlled by the adsorbed phase HA content in the porous medium. Furthermore, it was observed that pH levels influenced the transport behavior of TOL and DCM when adsorbed phase HA was present since adsorbed phase HA transformation into mobile phase was regulated by pH levels. The transport patterns can be effectively simulated using the chemical nonequilibrium two-site sorption model in HYDRUS-1D, accurately reflecting the retardation coefficients and transport distances based on model parameters. This work sheds new light on the regulatory role of adsorbed phase HA in TOL and DCM transport under diverse hydrochemical conditions, with implications for accurately depicting the behavior of combined pollutants, optimizing the remediation strategies and improving remediation efficiency in contaminated sites.

Efficient degradation of aqueous dichloromethane by an enhanced microbial electrolysis cell: Degradation kinetics, microbial community and metabolic mechanisms.

Dichloromethane (DCM) has been listed as a toxic and harmful water pollutant, and its removal needs attention. Microbial electrolysis cells (MECs) are viewed as a promising alternative for pollutant removal, which can be strengthened from two aspects: microbial inoculation and acclimation. In this study, the MEC for DCM degradation was inoculated with the active sludge enhanced by Methylobacterium rhodesianum H13 (strain H13) and then acclimated in the form of a microbial fuel cell (MFC). Both the introduction of strain H13 and the initiation in MFC form significantly promoted DCM degradation. The degradation kinetics were fitted by the Haldane model, with Vmax, Kh, Ki and vmax values of 103.2 mg/L/hr, 97.8 mg/L, 268.3 mg/L and 44.7 mg/L/hr/cm2, respectively. The cyclic voltammogram implies that DCM redox reactions became easier with the setup of MEC, and the electrochemical impedance spectrogram shows that the acclimated and enriched microbes reduced the charge transfer resistance from the electrode to the electrolyte. In the biofilm, the dominant genera shifted from Geobacter to Hyphomicrobium in acclimation stages. Moreover, Methylobacterium played an increasingly important role. DCM metabolism mainly occurred through the hydrolytic glutathione S-transferase pathway, given that the gene dcmA was identified rather than the dhlA and P450/MO. The exogenous electrons facilitated the reduction of GSSG, directly or indirectly accelerating the GSH-catalyzed dehalogenation. This study provides support for the construction of an efficient and stable MEC for DCM removal in water environment.

Dichloromethane as C1 Synthon for the Photoredox Catalytic Cyclopropanation of Aromatic Olefins.

Dichloromethane, as a readily available and inexpensive C1 synthon is proposed as a powerful building block for cyclopropanation of alkenes under mild conditions. Herein, we report a highly efficient and versatile dual photoredox system, involving a nickel aminopyridine coordination complex and a photocatalyst, for the cyclopropanation of aromatic olefins using dichloromethane, under visible-light irradiation. The cyclopropanation protocol has been successfully applied at gram scale. Mechanistic studies suggest a Ni(II) pyridyl radical complex as the key intermediate for the homolytic cleavage of the Csp3-Cl bond, generating a chloromethyl radical that is captured by the olefin coupling partner. Our findings also highlight the versatility of this methodology. By directing the radical/polar crossover process, we were able to selectively drive the reaction towards either the formation of cyclopropyl derivatives or the corresponding non-cyclic alkyl chloride products. The methodology also successfully apply to geminal dichloroalkanes, including the formation of spiro[2,2] compounds. Moreover, our methodology extends to the synthesis of deuterium-labelled cyclopropanes, demonstrating its utility in isotopic labelling and broadening its applicability in chemical synthesis and drug development.

Hydrochromic Perovskite System with Reversible Blue-Green Color for Advanced Anti-Counterfeiting.

The intrinsic instability of halide perovskites toward to external stimulus, has created a competitive advantage for designing stimuli-responsive materials. However, the external environment tuning reversibly fluorescence emission of perovskite system is still limited. In this work, humidity is verified to act as a new option to modulate the emission properties of mixed-halide perovskite. The perovskite nanocrystals (PNCs) photoirradiated in dichloromethane are easily and stably redispersed in water, and emit bright fluorescence which is quite different from the original. Moreover, the perovskites confined on glass slide can reversibly switch their fluorescence between blue and green colors under moisture. It is demonstrated that the factors of different solubilities of CsCl and CsBr in water, the structural transformation of perovskites and the confine of glass matrix play key roles in the reversible transformation. Finally, the combination of hydrochromic CsPb(Brx Cly )3 and water-resistant CsPb(Brx Cly )3 -polymethyl methacrylate have been applied in advanced anti-counterfeiting, which greatly improves the information security. This work not only give an insight into the effects of humidity on fluorescence and structures of PNCs, but also offer a new class of hydrochromic PNCs materials based on reversible emission transformation for potential application in sensors, anti-counterfeiting and information encryption.

A Multifunctional Dehalobacter? Tandem Chloroform and Dichloromethane Degradation in a Mixed Microbial Culture.

Chloroform (CF) and dichloromethane (DCM) contaminate groundwater sites around the world but can be cleaned up through bioremediation. Although several strains of Dehalobacter restrictus can reduce CF to DCM and multiple Peptococcaceae can ferment DCM, these processes cannot typically happen simultaneously due to CF sensitivity in the known DCM-degraders or electron donor competition. Here, we present a mixed microbial culture that can simultaneously metabolize CF and DCM and create an additional enrichment culture fed only DCM. Through genus-specific quantitative polymerase chain reaction, we find that Dehalobacter grows while either CF alone or DCM alone is converted, indicating its involvement in both metabolic steps. Additionally, the culture was maintained for over 1400 days without the addition of an exogenous electron donor, and through electron balance calculations, we show that DCM metabolism would produce sufficient reducing equivalents (likely hydrogen) for CF respiration. Together, these results suggest intraspecies electron transfer could occur to continually reduce CF in the culture. Minimizing the addition of electron donor reduces the cost of bioremediation, and "self-feeding" could prolong bioremediation activity long after donor addition ends. Overall, understanding this mechanism informs strategies for culture maintenance and scale-up and benefits contaminated sites where the culture is employed for remediation worldwide.

Compartment-related aspects of XoxF protein functionality in Methylorubrum extorquens DM4 analysed using its cytoplasmic targeting.

The impact of periplasmic localisation on the functioning of the XoxF protein was evaluated in the well-studied dichloromethane-utilising methylotroph Methylorubrum extorquens DM4, which harbors only one paralogue of the xoxF gene. It was found that the cytoplasmic targeting of XoxF by expression of the corresponding gene without the sequence encoding the N-terminal signal peptide does not impair the activation and lanthanide-dependent regulation of the MxaFI-methanol dehydrogenase genes. Analysis of the viability of ΔxoxF cells complemented with the full-length and truncated xoxF gene also showed that the expression of cytoplasmically targeted XoxF even increases the resistance to acids. These results contradict the proposed function of the XoxF protein as an extracytoplasmic signal sensor. At the same time, the observed dynamics of growth with methanol, as well as with dichloromethane of strains expressing cytoplasmic-targeted XoxF, indicate the probable enzymatic activity of lanthanide-dependent methanol dehydrogenase in this compartment. Herewith, the only available substrate for this enzyme in cells growing with dichloromethane was formaldehyde, which is produced during the primary metabolism of the mentioned halogenated toxicant directly in the cytosol. These findings suggest that the maturation of XoxF-methanol dehydrogenase may occur already in the cytoplasm, while the factors changing affinity of this enzyme for formaldehyde are apparently absent there. Together with the demonstrated functioning of an enhancer-like upstream activating sequence in the promoter region of the xoxF gene in M. extorquens DM4, the obtained information enriches our understanding of the regulation, synthesis and role of the XoxF protein.

New pyrrolo[3,2-b]pyrroles with AIE characteristics for detection of dichloromethane and chloroform.

Three new pyrrolo[3,2-b]pyrrole derivatives containing methoxyphenyl, pyrene or tetraphenylethylene (TPE) units (compounds 1-3) have been designed, synthesized and fully characterized. The aggregation-induced emission (AIE) properties of compounds 1-3 were tested in different water fraction (fw ) of tetrahydrofuran (THF). The pyrrolo[3,2-b]pyrrole derivative 3 containing TPE units exhibited typical AIE features with an enhanced emission (∼32-fold) in the solid state versus in solution; compounds 1 and 2 exhibited an aggregation-caused quenching effect. In addition, the steric and electronic effects of the peripheral moieties on the emission behavior, both in solution and in the solid state, have been investigated. Moreover, pyrrolo[3,2-b]pyrrole 1 exhibits high sensitivity and selectivity for dichloromethane and chloroform solvents, with the system displaying a new emission peak and fast response time under ultraviolet irradiation.

Anaerobic Biodegradation of Chloroform and Dichloromethane with a Dehalobacter Enrichment Culture.

Chloroform (CF) and dichloromethane (DCM) are among the more commonly identified chlorinated aliphatic compounds found in contaminated soil and groundwater. Complete dechlorination of CF has been reported under anaerobic conditions by microbes that respire CF to DCM and others that biodegrade DCM. The objectives of this study were to ascertain if a commercially available bioaugmentation enrichment culture (KB-1 Plus CF) uses an oxidative or fermentative pathway for biodegradation of DCM and to determine if the products from DCM biodegradation can support organohalide respiration of CF to DCM in the absence of an exogenous electron donor. In various treatments with the KB-1 Plus CF culture to which 14C-CF was added, the predominant product was 14CO2, indicating that oxidation is the predominant pathway for DCM. Recovery of 14C-DCM when biodegradation was still in progress confirmed that CF first undergoes reductive dechlorination to DCM. 14C-labeled organic acids, including acetate and propionate, were also recovered, suggesting that synthesis of organic acids provides a sink for the electron equivalents from oxidation of DCM. When the biomass was washed to remove organic acids from prior additions of exogenous electron donor and only CF and DCM were added, the culture completely dechlorinated CF. The total amount of DCM added was not sufficient to provide the electron equivalents needed to reduce CF to DCM. Thus, the additional reducing power came via the DCM generated from CF reduction. Nevertheless, the rate of CF consumption was considerably lower compared to that of treatments that received an exogenous electron donor. IMPORTANCE Chloroform (CF) and dichloromethane (DCM) are among the more commonly identified chlorinated aliphatic compounds found in contaminated soil and groundwater. One way to address this problem is to add microbes to the subsurface that can biodegrade these compounds. While microbes are known that can accomplish this task, less is known about the pathways used under anaerobic conditions. Some use an oxidative pathway, resulting mainly in carbon dioxide. Others use a fermentative pathway, resulting in formation of organic acids. In this study, a commercially available bioaugmentation enrichment culture (KB-1 Plus CF) was evaluated using carbon-14 labeled chloroform. The main product formed was carbon dioxide, indicating the use of an oxidative pathway. The reducing power gained from oxidation was shown to support reductive dechlorination of CF to DCM. The results demonstrate the potential to achieve full dechlorination of CF and DCM to nonhazardous products that are difficult to identify in the field.

Identification and widespread environmental distribution of a gene cassette implicated in anaerobic dichloromethane degradation.

Anthropogenic activities and natural processes release dichloromethane (DCM, methylene chloride), a toxic chemical with substantial ozone-depleting capacity. Specialized anaerobic bacteria metabolize DCM; however, the genetic basis for this process has remained elusive. Comparative genomics of the three known anaerobic DCM-degrading bacterial species revealed a homologous gene cluster, designated the methylene chloride catabolism (mec) gene cassette, comprising 8-10 genes encoding proteins with 79.6%-99.7% amino acid identities. Functional annotation identified genes encoding a corrinoid-dependent methyltransferase system, and shotgun proteomics applied to two DCM-catabolizing cultures revealed high expression of proteins encoded on the mec gene cluster during anaerobic growth with DCM. In a DCM-contaminated groundwater plume, the abundance of mec genes strongly correlated with DCM concentrations (R2  = 0.71-0.85) indicating their potential value as process-specific bioremediation biomarkers. mec gene clusters were identified in metagenomes representing peat bogs, the deep subsurface, and marine ecosystems including oxygen minimum zones (OMZs), suggesting a capacity for DCM degradation in diverse habitats. The broad distribution of anaerobic DCM catabolic potential infers a role for DCM as an energy source in various environmental systems, and implies that the global DCM flux (i.e., the rate of formation minus the rate of consumption) might be greater than emission measurements suggest.

Evaluation of the Flexibility for Catalytic Ozonation of Dichloromethane over Urchin-Like CuMnOx in Flue Gas with Complicated Components.

The evaluation of the poisoning effect of complex components in practical gas on DCM (dichloromethane) catalytic ozonation is of great significance for enhancing the technique's environmental flexibility. Herein, Ca, Pb, As, and NO/SO2 were selected as a typical alkaline-earth metal, heavy metal, metalloid, and acid gas, respectively, to evaluate their interferences on catalytic behaviors and surface properties of an optimized urchin-like CuMn catalyst. Ca/Pb loading weakens the formation of oxygen vacancies, oxygen mobility, and acidity due to the fusion of Mn-Ca/Pb-O, leading to their inferior catalytic performance with poor CO2 selectivity and mineralization rate. Noticeably, the presence of As induces excessively strong acidity, facilitating the inevitable formation of byproducts. Catalytic co-ozonation of NO/DCM is achieved with stoichiometric ozone addition. Unfortunately, SO2 introduction brings irreversible deactivation due to strong competition adsorption and the loss of active sites. Unexpectedly, Ca loading protects active sites from an attack by SO2. The formation of unstable sulfites and the released Mn-O structure offset the negative effect from SO2. Overall, the catalytic ozonation of DCM exhibits a distinctive priority in the antipoisoning of metals with the maintenance of DCM conversion. The construction of more stable acid sites should be the future direction of catalyst design; otherwise, catalytic ozonation should be arranged together with post heavy metal capture and a deacidification system.

Oxy-Anionic Doping: A New Strategy for Improving Selectivity of Ru/CeO2 with Synergetic Versatility and Thermal Stability for Catalytic Oxidation of Chlorinated Volatile Organic Compounds.

Understanding the formation and inhibition of more toxic polychlorinated byproducts from the catalytic oxidation elimination of chlorinated volatile organic compounds (Cl-VOCs) and unveiling efficient strategies have been essential and challenging. Here, RuOx supported on CePO4-doped CeO2 nanosheets (Ru/Pi-CeO2) is designed for boosting catalytic oxidation for the removal of dichloromethane (DCM) as a representative Cl-VOC. The promoted acid strength/number and sintering resistance due to the doping of electron-rich and thermally stable CePO4 are observed along with the undescended redox ability and the exposed multi-active sites, which demonstrates a high activity and durability of DCM oxidation (4000 mg/m3 and 15,000 mL/g·h, stable complete-oxidation at 300 °C), exceptional versatility for different Cl-VOCs, alkanes, aromatics, N-containing VOCs, CO and their multicomponent VOCs, and enhanced thermal stability. The suppression of polychlorinated byproducts is determined over Ru/Pi-CeO2 and oxy-anionic S, V, Mo, Nb, or W doping CeO2, thus the oxy-anionic doping strategy is proposed based on the quenching of the electron-rich oxy-anions on chlorine radicals. Moreover, the simple mechanical mixing with these oxy-anionic salts is also workable even for other catalysts such as Co, Sn, Mn, and noble metal-based catalysts. This work offers further insights into the inhibition of polychlorinated byproducts and contributes to the convenient manufacture of monolithic catalysts with superior chlorine-poisoning resistance for the catalytic oxidation of Cl-VOCs.

Dechlorination of dichloromethane by a biofilter enriched with electroactive bacteria: Performance, kinetics, and microbial community.

Dichloromethane (DCM) is a recalcitrant volatile organic compound that exhibits biological toxicity and bioaccumulation. In this study, gaseous DCM was removed using an electroactive bacterial biofilter (EBB) with graphite rod as the anode and carbon felt as the cathode. The highest removal efficiency (97.09%) was achieved at a cathodic potential of -600 mV (vs. Ag/AgCl). The EBB had a maximum elimination capacity of 79.29 g m-3 h-1 when the inlet load was 96.48 g m-3 h-1. There was no substrate inhibition phenomenon observed in the EBB, and the Michaelis-Menten model was used to describe the kinetics of the EBB. High-throughput sequencing indicated that electroactive genera such as Rhodanobacter sp., Sphingomonas sp., Pseudomonas sp., Chryseobacterium sp., Pseudochrobactrum sp., and Mycobacterium sp. dominated the EBB. The microbial communities were stable and were slightly affected by the DCM inlet concentration. The results can be applied for the effective treatment of recalcitrant volatile organic compounds (VOCs).

Pterocarpus mildbraedii leaf extract ebbs propanil-induced oxidative and apoptotic damage in the liver of rats.

Phytochemicals derived from plant sources are well recognized as sources of pharmacologically potent drugs in the treatment of several oxidative stress-related ailments. Dichloromethane/methanol (1:1) leaf extract of Pterocarpus mildbraedii was evaluated for its possible protection against oxidative stress and apoptosis in the liver of male Wistar rats exposed to propanil (PRP). In the experimental design, olive oil served as the vehicle, and rats were grouped into control (2 mL/kg olive oil), PRP (200 mg/kg/day), Pterocarpus mildbraedii extract (200 mg/kg/day), and Pterocarpus mildbraedii extract (200 mg/kg/day)+PRP (200 mg/kg/day), and treated daily, p.o., for seven days. Oxidative stress parameters, B-cell lymphoma 2 (Bcl-2), Bcl 2-associated X protein (Bax), p53, caspases (9/3), and terminal transferase dUTP nick end labeling (TUNEL) assays were observed in all groups. Propanil significantly elevated superoxide dismutase and lipid peroxidation levels, while concomitantly depleting GSH and p53 levels. Further, PRP enhanced the expressions of caspase-9, caspase-3, Bax, and TUNEL-positive cells in the liver of rats. However, these observed alterations were reversed following treatment with Pterocarpus mildbraedii extract. Our studies suggest that Pterocarpus mildbraedii extract protected against PRP toxicity by reducing oxidative stress and attenuating critical endpoints in the intrinsic apoptotic pathway.

Airlift two-phase partitioning bioreactor for dichloromethane removal: Silicone rubber stimulated biodegradation and its auto-circulation.

Solid non-aqueous phases (NAPs), such as silicone rubber, have been used extensively to improve the removal of volatile organic compounds (VOCs). However, the removal of VOCs is difficult to be further improved because the poor understanding of the mass transfer and reaction processes. Further, the conventional reactors were either complicated or uneconomical. In view of this, herein, an airlift bioreactor with silicone rubber was designed and investigated for dichloromethane (DCM) treatment. The removal efficiency of Reactor 1 (with silicone rubber) was significantly higher than that of Reactor 2 (without silicone rubber), with corresponding higher chloride ion and CO2 production. It was found that Reactor 1 achieved a much better DCM shock tolerance capability and biomass stability than Reactor 2. Silicone rubber not only enhanced the mass transfer in terms of both gas/liquid and gas/microbial phases, but also decreased the toxicity of DCM to microorganisms. Noteworthily, despite the identical inoculum used, the relative abundance of potential DCM-degrading bacteria in Reactor 1 (91.2%) was much higher than that in Reactor 2 (24.3%) at 216 h. Additionally, the silicone rubber could be automatically circulated in the airlift bioreactor due to the driven effect of the airflow, resulting in a significant reduction of energy consumption.

[Determination of Dichloromethane in Blood with Headspace Gas Chromatography and Gas Chromatography-Mass Spectrometry].

Objective: To establish a method for qualitative determination of dichloromethane (DCM) in blood by gas chromatography-mass spectrometry (GC-MS) and quantitative determination of DCM in blood by headspace gas chromatography (HS-GC), and to provide reliable support for forensic examination and analysis of poisoning or deaths caused by DCM. Methods: 0.5 mL blood sample was collected, added into headspace vial with chloroform as the internal standard, and processed by heating at 65 °C and evacuation treatment. The intermediate gas in the headspace vial was analyzed by GC-MS for qualitative validation of the method and by HS-GC for quantitative validation of the method. The method was then applied in forensic case analysis. Results: Qualitative validation of the examination method by GC-MS found that the chromatographic peak and mass spectral characteristic ions were specific in samples added with DCM, and that no interference was observed in the blank negative samples. The limit of detection (LOD) was 5 µg/mL. Quantitative method validation by HS-GC found that the chromatographic peak of DCM was well separated from those of eight other volatile compounds, with the resolution>1.5 in all cases; the lower limit of quantification (LOQ) was 20 µg/mL and good linearity was shown within the range of 20 and 1000 µg/mL, R>0.999; the intra-day test precision and inter-day test precision were good (relative standard deviation, or RSD<15% for both) and test accuracy was high (relative error, or δ<15%). With the method established in the study, DCM was detected successfully in the blood of two fatal cases caused by DCM poisoning, with the blood concentration being 470 µg/mL and 915 µg/mL, respectively. Conclusion: This method is shown to be a rapid, stable and accurate approach to the qualitative and quantitative forensic and toxicological analysis of DCM in blood in DCM poisoning cases or deaths caused by DCM.

[A report of 7 cases of toxic liver disease caused by mixed gas in a shoe factory].

Trichloromethane and dichloromethane have toxic effects on the liver, and incidents of toxic liver disease caused by them have been reported from time to time. In November 2021, an occupational chemical poisoning incident occurred in a shoe factory in Huidong County, Guangdong Province. After testing the air at the scene and analyzing the clinical data of the poisoning patients, it was preliminarily determined that the poisoning was caused by a mixed gas poisoning incident dominated by trichoromethane. At admission, the liver function of 7 patients was tested for different degrees of impairment (alanine aminotransferase 145-2501 IU/L, aspartate aminotransferase 66-1286 IU/L). The volatile organic components of on-site raw and auxiliary materials were analyzed. The percentages of trichloromethane and dichloromethane detected in 103A powder glue used in the poisoning workshop site accounted for 21.11% and 6.77% respectively.

Bruceine A induces cell growth inhibition and apoptosis through PFKFB4/GSK3ß signaling in pancreatic cancer.

Pancreatic cancer is one of the most aggressive cancers with a poor prognosis and 5-year low survival rate. In the present study, we report that bruceine A, a quassinoid found in Brucea javanica (L.) Merr. has a strong antitumor activity against human pancreatic cancer cells both in vitro and in vivo. Human proteome microarray reveals that 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4) is the candidate target of bruceine A and both fluorescence measurement and microscale thermophoresis suggest bruceine A binds to PFKFB4. Bruceine A suppresses glycolysis by inhibiting PFKFB4, leading to cell cycle arrest and apoptosis in MIA PaCa-2 cells. Furthermore, glycogen synthase kinase-3 ß (GSK3ß) is identified as a downstream target of PFKFB4 and an PFKFB4-interacting protein. Moreover, bruceine A induces cell growth inhibition and apoptosis through GSK3ß, which is dysregulated in pancreatic cancer and closely related to the prognosis. In all, these findings suggest that bruceine A inhibits human pancreatic cancer cell growth via PFKFB4/GSK3ß-mediated glycolysis, and it may serve as a potent agent for curing human pancreatic cancer.

Improvement of interfacial contact for efficient PCBM/MAPbI3planar heterojunction solar cells with a binary antisolvent mixture treatment.

Atomic-force microscopic images, x-ray diffraction patterns, Urbach energies and photoluminescence quenching experiments show that the interfacial contact quality between the hydrophobic [6,6]-phenyl-C61-buttric acid methyl ester (PCBM) thin film and hydrophilic CH3NH3PbI3(MAPbI3) thin film can be effectively improved by using a binary antisolvent mixture (toluene:dichloromethane or chlorobenzene:dichloromethane) in the anti-solvent mixture-mediated nucleation process, which increases the averaged power conversion efficiency of the resultant PEDOT:PSS (P3CT-Na) thin film based MAPbI3solar cells from 13.18% (18.52%) to 13.80% (19.55%). Beside, the use of 10% dichloromethane (DCM) in the binary antisolvent mixture results in a nano-textured MAPbI3thin film with multicrystalline micrometer-sized grains and thereby increasing the short-circuit current density and fill factor (FF) of the resultant solar cells. It is noted that a remarkable FF of 80.33% is achieved, which can be used to explain the stable photovoltaic performance without additional encapsulations.