Temperature-dependent excitonic emission characteristics of highly crystallized carbon nitride nanosheets.

Highly-crystallized carbon nitride (HCCN) nanosheets exhibit significant potential for advancements in the field of photoelectric conversion. However, to fully exploit their potential, a thorough understanding of the fundamental excitonic photophysical processes is crucial. Here, the temperature-dependent excitonic photoluminescence (PL) of HCCN nanosheets and amorphous polymeric carbon nitride (PCN) is investigated using steady-state and time-resolved PL spectroscopy. The exciton binding energy of HCCN is determined to be 109.26 meV, lower than that of PCN (207.39 meV), which is attributed to the ordered stacking structure of HCCN with a weaker Coulomb interaction between electrons and holes. As the temperature increases, a noticeable reduction in PL lifetime is observed on both the HCCN and PCN, which is ascribed to the thermal activation of carrier trapping by the enhanced electron-phonon coupling effect. The thermal activation energy of HCCN is determined to be 102.9 meV, close to the value of PCN, due to their same band structures. Through wavelength-dependent PL dynamics analysis, we have identified the PL emission of HCCN as deriving from the transitions:σ*-LP,π*-π, andπ*-LP, where theπ*-LP transition dominants the emission because of the high excited state density of the LP state. These results demonstrate the impact of high-crystallinity on the excitonic emission of HCCN materials, thereby expanding their potential applications in the field of photoelectric conversion.

Potential source and health risks of black carbon based on MERRA-2 reanalysis data in a typical industrial city of North China Plain.

Black carbon (BC) significantly affects climate, environmental quality, and human health. This study utilised Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), which can compensate for the shortcomings of ground BC monitoring in spatial-temporal distribution to study the pollution characteristics of BC and potential pollution sources in a typical industrial city (Xinxiang) with serious air pollution in northern China. The results showed that average daily ground observation and MERRA-2 concentration of BC of 7.33 µg m-3 and 9.52 µg m-3. The mean BC concentration derived from MERRA-2 reanalysis data was higher than ground measurement due to resolution limitations and pollution from the northern regions. The reliability of the MERRA-2 data was confirmed through correlation analysis. Consideration of the spatial distribution of BC from MERRA-2 and incorporating the potential source contribution function (PSCF), concentration-weighted trajectory (CWT), and emission inventory, other possible source areas and primary sources of BC in Xinxiang were investigated. The results indicated that implementing transportation and residential emission control measures in Henan Province and its surrounding provinces, such as Hebei Province, will effectively decrease the BC level in Xinxiang City. A passively smoked cigarettes model was used to evaluate the risk of BC exposure. The percentage of lung function decrement (PLFD) was the highest in school-age children, while the impact on lung cancer (LC) health risk was comparatively lower. Notably, the BC health risk in Xinxiang was lower than in most cities across Asia.

SLC1A3 contributes to L-asparaginase resistance in solid tumors.

L-asparaginase (ASNase) serves as an effective drug for adolescent acute lymphoblastic leukemia. However, many clinical trials indicated severe ASNase toxicity in patients with solid tumors, with resistant mechanisms not well understood. Here, we took a functional genetic approach and identified SLC1A3 as a novel contributor to ASNase resistance in cancer cells. In combination with ASNase, SLC1A3 inhibition caused cell cycle arrest or apoptosis, and myriads of metabolic vulnerabilities in tricarboxylic acid (TCA) cycle, urea cycle, nucleotides biosynthesis, energy production, redox homeostasis, and lipid biosynthesis. SLC1A3 is an aspartate and glutamate transporter, mainly expressed in brain tissues, but high expression levels were also observed in some tumor types. Here, we demonstrate that ASNase stimulates aspartate and glutamate consumptions, and their refilling through SLC1A3 promotes cancer cell proliferation. Lastly, in vivo experiments indicated that SLC1A3 expression promoted tumor development and metastasis while negating the suppressive effects of ASNase by fueling aspartate, glutamate, and glutamine metabolisms despite of asparagine shortage. Altogether, our findings identify a novel role for SLC1A3 in ASNase resistance and suggest that restrictive aspartate and glutamate uptake might improve ASNase efficacy with solid tumors.

CTGF promotes the repair and regeneration of alveoli after acute lung injury by promoting the proliferation of subpopulation of AEC2s.

BACKGROUND: Functional alveolar regeneration is essential for the restoration of normal lung homeostasis after acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Lung is a relatively quiescent organ and a variety of stem cells are recruited to participate in lung repair and regeneration after lung tissue injury. However, there is still no effective method for promoting the proliferation of endogenous lung stem cells to promote repair and regeneration. METHODS: Using protein mass spectrometry analysis, we analyzed the microenvironment after acute lung injury. RNA sequencing and image cytometry were used in the alveolar epithelial type 2 cells (AEC2s) subgroup identification. Then we used Sftpc+AEC2 lineage tracking mice and purified AEC2s to further elucidate the molecular mechanism by which CTGF regulates AEC2s proliferation both in vitro and in vivo. Bronchoalveolar lavage fluid (BALF) from thirty ARDS patients who underwent bronchoalveolar lavage was collected for the analysis of the correlation between the expressing of Krt5 in BALF and patients' prognosis. RESULTS: Here, we elucidate that AEC2s are the main facultative stem cells of the distal lung after ALI and ARDS. The increase of connective tissue growth factor (CTGF) in the microenvironment after ALI promoted the proliferation of AEC2s subpopulations. Proliferated AEC2s rapidly expanded and differentiated into alveolar epithelial type 1 cells (AEC1s) in the regeneration after ALI. CTGF initiates the phosphorylation of LRP6 by promoting the interaction between Krt5 and LRP6 of AEC2s, thus activating the Wnt signaling pathway, which is the molecular mechanism of CTGF promoting the proliferation of AEC2s subpopulation. CONCLUSIONS: Our study verifies that CTGF promotes the repair and regeneration of alveoli after acute lung injury by promoting the proliferation of AEC2s subpopulation.

Cytokine Biomarker Phenotype for Early Prediction and Triage of Sepsis in Blunt Trauma Patients.

BACKGROUND: Altered levels of inflammatory markers secondary to severe trauma present a major problem to physicians and are prone to interfering with the clinical identification of sepsis events. This study aimed to establish the profiles of cytokines in trauma patients to characterize the nature of immune responses to sepsis, which might enable early prediction and individualized treatments to be developed for targeted intervention. METHODS: A 15-plex human cytokine magnetic bead assay system was used to measure analytes in citrated plasma samples. Analysis of the kinetics of these cytokines was performed in 40 patients with severe blunt trauma admitted to our trauma center between March 2016 and February 2017, with an Injury Severity Score (ISS) greater than 20 with regard to sepsis (Sepsis-3) over a 14-d time course. RESULTS: In total, the levels of six cytokines were altered in trauma patients across the 1-, 3-, 5-, 7-, and 14-d time points. Additionally, IL-6, IL-10, IL-15, macrophage derived chemokine (MDC), GRO, sCD40 L, granulocyte colony-stimulating factor (G-CSF), and fibroblast growth factor (FGF)-2 levels could be used to provide a significant discrimination between sepsis and nonsepsis patients at day 3 and afterward, with an area under the curve (AUC) of up to 0.90 through a combined analysis of the eight biomarkers (P < 0.001). Event-related analysis demonstrated 1.5- to 4-fold serum level changes for these cytokines within 72 h before clinically apparent sepsis. CONCLUSIONS: Cytokine profiles demonstrate a high discriminatory ability enabling the timely identification of evolving sepsis in trauma patients. These abrupt changes enable sepsis to be detected up to 72 h before clinically overt deterioration. Defining cytokine release patterns that distinguish sepsis risk from trauma patients might enable physicians to initiate timely treatment and reduce mortality. Large prospective studies are needed to validate and operationalize the findings. TRIAL REGISTRATION: Clinicaltrials, NCT01713205. Registered October 22, 2012, https://register. CLINICALTRIALS: gov/NCT01713205.

Tim-3 regulates sepsis-induced immunosuppression by inhibiting the NF-κB signaling pathway in CD4 T cells.

Immunosuppression in response to severe sepsis remains a serious human health concern. Evidence of sepsis-induced immunosuppression includes impaired T lymphocyte function, T lymphocyte depletion or exhaustion, increased susceptibility to opportunistic nosocomial infection, and imbalanced cytokine secretion. CD4 T cells play a critical role in cellular and humoral immune responses during sepsis. Here, using an RNA sequencing assay, we found that the expression of T cell-containing immunoglobulin and mucin domain-3 (Tim-3) on CD4 T cells in sepsis-induced immunosuppression patients was significantly elevated. Furthermore, the percentage of Tim-3+ CD4 T cells from sepsis patients was correlated with the mortality of sepsis-induced immunosuppression. Conditional deletion of Tim-3 in CD4 T cells and systemic Tim-3 deletion both reduced mortality in response to sepsis in mice by preserving organ function. Tim-3+ CD4 T cells exhibited reduced proliferative ability and elevated expression of inhibitory markers compared with Tim-3-CD4 T cells. Colocalization analyses indicated that HMGB1 was a ligand that binds to Tim-3 on CD4 T cells and that its binding inhibited the NF-κB signaling pathway in Tim-3+ CD4 T cells during sepsis-induced immunosuppression. Together, our findings reveal the mechanism of Tim-3 in regulating sepsis-induced immunosuppression and provide a novel therapeutic target for this condition.

A New Method for Programmable RNA Editing Using CRISPR Effector Cas13X.1.

Type VI CRISPR-Cas13 is the only CRISPR system that can bind and cleave RNA without DNase activity. We used the newly discovered, smaller Cas13X.1 protein to construct an editing system in mammalian cells, aiming to break the delivery restrictions of CRISPR-Cas13 system in vivo and promote the application of Cas13X system in clinical therapy. We employed exogenous fluorescence reporter gene mCherry and endogenous gene transketolase (TKT) closely related to cancer cell metabolism as target genes to evaluate the Cas13X.1 system. The recombinant plasmids targeting exogenous gene mCherry and endogenous gene TKT were constructed based on Cas13X.1 backbone plasmid. The editing efficiency, protein expression level, downstream gene transcript level and safety of Cas13X.1 system were evaluated. Both TKT transcripts of endogenous genes and mCherry transcripts of exogenous genes were significantly degraded by Cas13X.1 system with a knockdown efficiency up to 50%. At the same time, Cas13X.1 down-regulated the expression of the corresponding protein level in the editing of transcripts. In addition, the transcripts of key metabolic enzymes related to TKT were also down-regulated synchronously, suggesting that the degradation of TKT transcripts by Cas13X.1 system affected the main metabolic pathways related to TKT. The morphology, RNA integrity and apoptosis of cells loaded with Cas13X.1 system were not affected. The Cas13X.1 system we constructed had strong RNA knockdown ability in mammalian cells with low cellular toxicity. Compared with other CRISPR-Cas13 systems, Cas13X.1 system with smaller molecular weight has more advantages in vivo delivery. The Cas13X.1 system targeting TKT transcripts also provides an alternative method for the study of anti-cancer therapy.

Magnetic Biochar Derived from Fenton Sludge/CMC for High-Efficiency Removal of Pb(II): Synthesis, Application, and Mechanism.

Magnetic biochar composites (MBC) were developed by a simple one-step pyrolysis method using Fenton sludge waste solid and carboxymethyl cellulose sodium. Detailed morphological, chemical, and magnetic characterizations corroborate the successful fabrication of MBC. Batch adsorption experiments show that the synthesized MBC owns high-efficiency removal of Pb(II), accompanied by ease-of-separation from aqueous solution using magnetic field. The experiment shows that the equilibrium adsorption capacity of MBC for Pb(II) can reach 199.9 mg g-1, corresponding to a removal rate of 99.9%, and the maximum adsorption capacity (qm) reaches 570.7 mg g-1, which is significantly better than that of the recently reported magnetic similar materials. The adsorption of Pb(II) by MBC complies with the pseudo second-order equation and Langmuir isotherm model, and the adsorption is a spontaneous, endothermic chemical process. Investigations on the adsorption mechanism show that the combination of Pb(II) with the oxygen-containing functional groups (carboxyl, hydroxyl, etc.) on biochar with a higher specific surface area are the decisive factors. The merits of reusing solid waste resource, namely excellent selectivity, easy separation, and simple preparation make the MBC a promising candidate of Pb(II) purifier.

A Bifunctional BiOBr/ZIF-8/ZnO Photocatalyst with Rich Oxygen Vacancy for Enhanced Wastewater Treatment and H2O2 Generation.

Photocatalytic technology is considered an ideal approach for clean energy conversion and environmental pollution applications. In this work, a bifunctional BiOBr/ZIF-8/ZnO photocatalyst was proposed for removing phenols in wastewater and generating hydrogen peroxide. Insights from scanning electron microscopy measurements revealed the well-dispersion of ZIF-8/ZnO was on the BiOBr layer, which could effectively prevent agglomeration of ZIF-8 and facilitate the separation of carriers. In addition, the optimal H2O2 yield of the BiOBr/ZIF-8/ZnO sample could reach 116 mmol·L-1·g-1 within 2 h, much higher than that of pure BiOBr (with the value of 82 mmol·L-1·g-1). The optimal BiOBr/ZIF-8/ZnO sample could also remove 90% of the phenol or bisphenol A in 2 h, and its kinetic constants were 3.8 times and 2.3 times that of pure BiOBr, respectively. Based on the analysis of the various experimental characterizations, the photocatalytic mechanism of the S-scheme BiOBr/ZIF-8/ZnO composite for the degradation of phenolic pollutants and generation of H2O2 was proposed. The formation of the heterojunction and the oxygen vacancy work together to significantly improve its photocatalytic efficiency. In addition, the BiOBr/ZIF-8/ZnO catalyst has a certain impact on the degradation of phenol in actual wastewater, providing a way to effectively remove refractory pollutants and generate H2O2 in actual water.

Electrotaxis of alveolar epithelial cells in direct-current electric fields.

PURPOSE: This study aims to elucidate the electrotaxis response of alveolar epithelial cells (AECs) in direct-current electric fields (EFs), explore the impact of EFs on the cell fate of AECs, and lay the foundation for future exploitation of EFs for the treatment of acute lung injury. METHODS: AECs were extracted from rat lung tissues using magnetic-activated cell sorting. To elucidate the electrotaxis responses of AECs, different voltages of EFs (0, 50, 100, and 200 mV/mm) were applied to two types of AECs, respectively. Cell migrations were recorded and trajectories were pooled to better demonstrate cellular activities through graphs. Cell directionality was calculated as the cosine value of the angle formed by the EF vector and cell migration. To further demonstrate the impact of EFs on the pulmonary tissue, the human bronchial epithelial cells transformed with Ad12-SV40 2B (BEAS-2B cells) were obtained and experimented under the same conditions as AECs. To determine the influence on cell fate, cells underwent electric stimulation were collected to perform Western blot analysis. RESULTS: The successful separation and culturing of AECs were confirmed through immunofluorescence staining. Compared with the control, AECs in EFs demonstrated a significant directionality in a voltage-dependent way. In general, type Ⅰ alveolar epithelial cells migrated faster than type Ⅱ alveolar epithelial cells, and under EFs, these two types of cells exhibited different response threshold. For type Ⅱ alveolar epithelial cells, only EFs at 200 mV/mm resulted a significant difference to the velocity, whereas for, EFs at both 100 mV/mm and 200 mV/mm gave rise to a significant difference. Western blotting suggested that EFs led to an increased expression of a AKT and myeloid leukemia 1 and a decreased expression of Bcl-2-associated X protein and Bcl-2-like protein 11. CONCLUSION: EFs could guide and accelerate the directional migration of AECs and exert antiapoptotic effects, which indicated that EFs are important biophysical signals in the re-epithelialization of alveolar epithelium in lung injury.

Pharmacokinetics and metabolites of glycosides and lignans of the stem bark of Magnolia officinalis in functional dyspepsia and normal rats using liquid chromatography-tandem mass spectrometry.

The stem bark of Magnolia officinalis is a traditional Chinese medicine for the treatment of abdominal distention and functional dyspepsia. The pharmacokinetics of three glycosides (magnoloside A, magnoloside B, and syringin) and two lignans (honokiol and magnolol) in both normal and functional dyspepsia rats were firstly investigated by ultra-performance liquid chromatography-triple quadrupole mass spectrometry method and the influences of the coexisting compounds on the pharmacokinetic parameters of honokiol and magnolol were also studied. It was found that all of the five target compounds were quickly absorbed and eliminated in both normal and functional dyspepsia rats, while, their residence time was significantly decreased in pathological states except magnoloside A. The coexisting compounds in the stem bark of M. officinalis significantly reduced absorption and increased elimination of honokiol in vivo. It's worth noticing that the volume of distribution of lignan was quite lower than that of a glycoside. Moreover, the metabolic profiling of magnoloside A, honokiol, and magnolol in vivo was analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry method, from which three prototypes were identified and 35 metabolites were putatively characterized, and 18 unknown metabolites were reasonably characterized for the first time. The results indicated that sulfation and glucuronidation were the main metabolic pathways of honokiol and magnolol.

Continuous purification and culture of rat type 1 and type 2 alveolar epithelial cells by magnetic cell sorting.

PURPOSE: The incidence of acute lung injury (ALI) in severe trauma patients is 48% and the mortality rate following acute respiratory distress syndrome evolved from ALI is up to 68.5%. Alveolar epithelial type 1 cells (AEC1s) and type 2 cells (AEC2s) are the key cells in the repair of injured lungs as well as fetal lung development. Therefore, the purification and culture of AEC1s and AEC2s play an important role in the research of repair and regeneration of lung tissue. METHODS: Sprague-Dawley rats (3-4 weeks, 120-150 g) were purchased for experiment. Dispase and DNase I were jointly used to digest lung tissue to obtain a single-cell suspension of whole lung cells, and then magnetic bead cell sorting was performed to isolate T1α positive cells as AEC1s from the single-cell suspension by using polyclonal rabbit anti-T1a (a specific AEC1s membrane protein) antibodies combined with anti-rabbit IgG microbeads. Afterwards, alveolar epithelial cell membrane marker protein EpCAM was designed as a key label to sort AEC2s from the remaining T1α-neg cells by another positive immunomagnetic selection using monoclonal mouse anti-EpCAM antibodies and anti-mouse IgG microbeads. Cell purity was identified by immunofluorescence staining and flow cytometry. RESULTS: The purity of AEC1s and AEC2s was 88.3% ± 3.8% and 92.6% ± 2.7%, respectively. The cell growth was observed as follows: AEC1s stretched within the 12-16 h, but the cells proliferated slowly; while AEC2s began to stretch after 24 h and proliferated rapidly from the 2nd day and began to differentiate after 3 days. CONCLUSION: AEC1s and AEC2s sorted by this method have high purity and good viability. Therefore, our method provides a new approach for the isolation and culture of AEC1s and AEC2s as well as a new strategy for the research of lung repair and regeneration.

[Effect of modified Danggui Shaoyao Powder on SOCS3/TLR4 signaling pathway in rats with chronic atrophic gastritis].

This study aims to investigate the effect of modified Danggui Shaoyao Powder on the suppressor of cytokine signaling 3(SOCS3)/Toll-like receptor 4(TLR4) signaling pathway in gastric tissue of rats with chronic atrophic gastritis(CAG).Sixty SPF-grade SD rats were randomly assigned into the normal group, model group, Moluo Pills group, and high-, medium-, and low-dose groups of modified Danggui Shaoyao Powder.The rats in other groups except the normal group were treated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) to establish the CAG model.After 12 weeks of modeling, the rats in each group were administrated with corresponding drugs by gavage for 8 weeks.After the last administration, the histopathological changes of rat gastric mucosa were observed via hematoxylin-eosin(HE) staining.The serum levels of IL-6, TNF-α, and CRP were determined by enzyme-linked immunosorbent assay(ELISA).The mRNA levels of SOCS3 and TLR4 were determined by real-time PCR.The protein levels of SOCS3, TLR4, JAK2, p-JAK2, STAT3, and p-STAT3 in rat gastric tissue were measured by Western blot.Immunohistochemical method was employed to determine the protein levels of NF-κB, MyD88, NLRP3, Bcl-2, Bax, and Bad in rat gastric tissue.The results showed that modified Danggui Shaoyao Powder alleviated gastric mucosal atrophy of rats, significantly lowered the levels of IL-6, TNF-α, and CRP in rat serum, up-regulated the mRNA level of SOCS3, and down-regulated the mRNA level of TLR4 in rat gastric tissue.Furthermore, modified Danggui Shaoyao Powder up-regulated the protein level of SOCS3, down-regulated the protein levels of TLR4, p-JAK2, p-STAT3, NF-κB, MyD88, NLRP3, Bax, and Bad, and promoted the expression of Bcl-2 protein.Therefore, modified Danggui Shaoyao Powder may mitigate the gastric mucosal atrophy of rats by regulating the SOCS3/TLR4 signaling pathway.

In situ preparation of g-C3N4/polyaniline hybrid composites with enhanced visible-light photocatalytic performance.

The graphic carbon nitride/polyaniline (g-C3N4/PANI) hybrid composites were successfully synthesized by a facile in situ polymerization process under ice water bath. The photocatalytic activities of the g-C3N4/PANI composites were evaluated by using oxytetracycline (OTC) as model pollutants. The optimal g-C3N4/PANI composite (5%PANI: the g-C3N4/PANI hybrid with 5 wt.% of PANI) showed an enhancement degradation rate of 5-fold compared to that of conventional g-C3N4 under simulated-sunlight irradiation. In addition, the 5%PANI demonstrate significantly photocatalytic evolution H2 rate (163.2 µmol/(g⋅hr)) under the visible light irradiation. Furthermore, based on the results of optical performance and electrochemical testing, a possible mechanism was proposed, indicating that the incorporation of PANI into the traditional g-C3N4 can effectively tune the electronic structures, improve the photo-generated electrons-holes separation and enhance extensive absorption of visible light. Such a g-C3N4/PANI hybrid nanocomposites could be envisaged to possess great potentials in practical wastewater treatment and water splitting.

The predictive value of heart rate variability indices tested in early period after radiofrequency catheter ablation for the recurrence of atrial fibrillation.

INTRODUCTION: To explore the relationship between recurrence of atrial fibrillation (AF) and the autonomic nervous activity evaluated by heart rate variability (HRV) indices after radiofrequency catheter ablation (RFCA) in the early period. METHODS: We enrolled 102 patients with paroxysmal AF and tested the HRV indices by the high-resolution Holter electrocardiogram the next morning after RFCA. The HRV indices were compared between the non-recurrence group (n = 85) and the recurrence group (n = 17). RESULTS: The HRV indices included standard deviation of normal to normal intervals (SDNN), SDNN index, root-mean square successive differences (RMSSD), the proportion of normal to normal intervals differing by >50 millisecond (ms) (pNN50), high-frequency components (HF), low-frequency components (LF) and very low-frequency components were significantly higher in recurrence group than that in non-recurrence group, while no such difference was found for LF/HF. Based on the median value of the recurrent time (9 months), RMSSD (P = .012), pNN50 (P < .0001) and HF (P = .033) were lower in late recurrence group than that in early recurrence group. The Cox regression analyses indicated that higher values of RMSSD (P = .01), pNN50 (P = .02) and HF (P = .02) were associated with a higher risk of recurrence after adjusted for covariates. The receiver operating characteristic curves showed higher rates of clinical recurrence of AF after RFCA in patients with RMSSD ≥27.5 ms, pNN50 ≥4.5%, and HF ≥178.25 ms2 . CONCLUSIONS: Values of RMSSD, pNN50, and HF tested in the early period after RFCA could independently predict the recurrence of AF.

Wavefunction engineering for efficient photoinduced-electron transfer in CuInS2 quantum dot-sensitized solar cells.

The high efficiency of quantum dot-sensitized solar cells (QDSSCs) is a benefit of the highly efficient photoinduced-electron transfer (PET) to external electrodes. Here, we investigated how the surface defects and conduction-band (CB) offsets between core and shell materials affect the PET from CuInS2 quantum dots (QDs) by means of time-resolved femtosecond transient absorption and nanosecond photoluminescence spectroscopy. The transfer of 1S excited electrons from CuInS2 QDs to TiO2 films is demonstrated and we find that the surface-electron trapping can significantly reduce the efficiency of the PET. Though the electron trapping can be suppressed after ZnS surface passivation, the PET decreases significantly to a low efficiency of ∼33% from the type I CuInS2/ZnS core/shell QDs because of their low electron density at the surface of the QDs. The surface-electron density is increased with the strategy of wavefunction engineering by reducing the CB offset, which allows us to achieve a quasi-type II carrier confinement in CuInS2/CdS core/shell QDs. The PET efficiency appears to be as high as ∼95% from the CuInS2/CdS core/shell QDs, which is ascribed to synergistic effects of the surface passivation and enhanced delocalization of the electron wavefunction from the CuInS2 core to the CdS shell. Finally, we demonstrate that these new mechanistic understandings of the PET processes are crucial to improving the efficiency of CuInS2 QDSSCs.

Viability and distribution of bacteria immobilized on Sawdust@silica: The removal mechanism of phenanthrene in soil.

Immobilized cells (ICs) have been widely used to enhance the remediation of organic-contaminated soil (e.g., polycyclic aromatic hydrocarbons, PAHs). Once ICs are added to the heterogeneous soil, degradation hotspots are immediately formed near the carrier, leaving the remaining soil lack of degrading bacteria. Therefore, it remains unclear how ICs efficiently utilize PAHs in soil. In this study, the viability of Silica-IC (Cells@Sawdust@Silica) and the distribution of inoculated ICs and phenanthrene (Phe) in a slurry system (soil to water ratio 1:2) were investigated to explore the removal mechanism of PAHs by the ICs. Results showed that the Silica-IC maintained (i) good reproductive ability (displayed by the growth curve in soil and water phase), (ii) excellent stability, which was identified by the ratio of colony forming units in the soil phase to the water phase, the difference between the colony number and the DNA copies, and characteristics of the biomaterial observed by the FESEM, and (iii) high metabolic activity (the removal percentages of Phe in soil by the ICs were more than 95% after 48 h). Finally, the possible pathways for the ICs to efficiently utilize Phe in soil are proposed based on the distribution and correlation of Phe and ICs between the soil and water phase. The adsorption-degradation process was dominant, i.e., the enhanced degradation occurred between the ICs and carrier-adsorbed Phe. This study provided new insights on developing a bio-material for efficient bio-remediation of PAHs-contaminated soil.

Effects of hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure during activated sludge process.

Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N2O) generation during activated sludge processes. The hydrodynamic shear stress induced by aeration has a significant influence on sludge properties and is inevitable for wastewater treatment plants (WWTPs). In this study, the effects of aerobic induced hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure were investigated using three parallel sequencing batch reactors (SBRs) with identical dissolved oxygen (DO) concentrations. Results showed that with a shear stress increase from 1.5 × 10-2 N/m2 to 5.0 × 10-2 N/m2, the COD and NH4+-N removal rates were enhanced from 89.4% to 94.0% and from 93.9% to 98.0%, respectively, while the TN removal rate decreased from 66.0% to 56.5%. Settleability of the activated sludge flocs (ASFs) also increased with the enhancement of shear stress, due to variation in sludge properties including particle size, regularity, compactibility, and EPS (extracellular polymeric substances) composition. The increase in shear stress promoted oxygen diffusion within the ASFs and mitigated NO2--N accumulation, leading to a decrease in the N2O-N conversion rate from (4.8 ± 0.3)% to (2.2 ± 0.6)% (based on TN removal). Microbial analysis results showed that the functional bacteria involved in the biological nitrogen removal was closely related with shear stress. The increase in shear stress favored the enrichment of nitrite oxidizing bacteria (NOB) while suppressed the accumulation of ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (DNB).

A seriously air pollution area affected by anthropogenic in the central China: temporal-spatial distribution and potential sources.

This study used the officially released data by the Chinese air quality monitoring network to analyze the pollution characteristics of six air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3) for 29 cities in the Central Plains Economic Zone (CPEZ; China) in 2015. During 2015, serious particulate matter (PM) pollution often occurred, and the concentrations of PM2.5 and PM10 were 77 µg m-3 and 128 µg m-3, respectively. Air pollutants were at higher concentrations in the northern cities than those in the southern region of the CPEZ, and the correlation among the cities indicated that there was regional pollution in CPEZ. Generally, PM, SO2, NO2, and CO showed similar seasonal characteristics and the highest and lowest concentrations appeared in winter and summer, respectively. In addition, we used the HYSPLIT model and trajStat model to identify the potential source contribution function and concentration-weighted trajectory of Zhengzhou, the central city of CPEZ. More serious air pollution occurred when air masses were transported from the west of the CPEZ. Shaanxi Province, Hubei Province, Anhui Province and the northwest of the CPEZ were found to be the main exogenous sources of total PM with contributions of > 100 µg m-3 PM2.5 and > 180 µg m-3 PM10. Therefore, the concentrations of PM in 2015 at Zhengzhou were probably influenced by both long-distance transmission and local emissions.

Value of lung ultrasound score for evaluation of blast lung injury in goats.

PURPOSE: To establish a severe blast lung injury model of goats and investigate the feasibility of lung ultrasonic score in the evaluation of blast lung injury. METHODS: Twenty female healthy goats were randomly divided into three groups by different driving pressures: 4.0 MPa group (n = 4), 4.5 MPa group (n = 12) and 5.0 MPa group (n = 4). The severe blast lung injury model of goats was established using a BST-I bio-shock tube. Vital signs (respiration, heart rate and blood pressure), lung ultrasound score (LUS), PO2/FiO2 and extravascular lung water (EVLW) were measured before injury (0 h) and at 0.5 h, 3 h, 6 h, 9 h, 12 h after injury. Computed tomography scan was performed before injury (0 h) and at 12 h after injury for dynamic monitoring of blast lung injury and measurement of lung volume. The correlation of LUS with PaO2/FiO2, EVLW, and lung injury ratio (lesion volume/total lung volume*100%) was analyzed. All animals were sacrificed at 12 h after injury for gross observation of lung injury and histopathological examination. Statistical analysis was performed by the SPSS 22.0 software. The measurement data were expressed as mean ± standard deviation. The means of two samples were compared using independent-sample t-test. Pearson correlation analysis was conducted. RESULTS: (1) At 12 h after injury, the mortality of goats was 0, 41.67% and 100% in the 4.0 Mpa, 4.5 MPa and 5.0 MPa groups, respectively; the area of pulmonary hemorrhage was 20.00% ± 13.14% in the 4.0 Mpa group and 42.14% ± 15.33% in the 4.5 MPa group. A severe lung shock injury model was established under the driving pressure of 4.5 MPa. (2) The respiratory rate, heart rate, LUS and EVLW were significantly increased, while PaO2/FiO2 was significantly reduced immediately after injury, and then they gradually recovered and became stabilized at 3 h after injury. (3) LUS was positively correlated with EVLW (3 h: r = 0.597, 6 h: r = 0.698, 9 h: r = 0.729; p < 0.05) and lung injury ratio (12 h: r = 0.884, p < 0.05), negatively correlated with PaO2/FiO2 (3 h: r = -0.871, 6 h: r = -0.637, 9 h: r = -0.658; p < 0.05). CONCLUSION: We established a severe blast lung injury model of goats using the BST-I bio-shock tube under the driving pressure of 4.5 MPa and confirmed that ultrasound can be used for quick evaluation and dynamic monitoring of blast lung injury.