Molasses-based in situ bio-sequestration of Cr(VI) in groundwater under flow condition.

The in situ biosequestration of Cr(VI) in groundwater with molasses as the carbon source was studied based on column experiments and model simulation in this study. Compared with biological reduction, molasses-based chemical reduction did not cause significant Cr(VI) removal at molasses concentration as high as 1.14 g L-1. The molasses at a concentration as low as 0.57 g L-1 could support biofilm-based Cr(VI) sequestration under flow conditions and showed better sequestration performances than D-glucose and emulsified vegetable oil (8 g L-1). The existence of molasses (1.14 g L-1) decreased the pH of the effluent from 7.5 to 6.3 and the oxidation-reduction potential from 275 mV to 220 mV in the groundwater, which was responsible for reduction and thus the sequestration of Cr(VI). Advection-dispersion-reaction model well described the process of the Cr(VI) transport with biosequestration in the column (R2 ≥ 0.96). Owing to the Cr(VI) toxicity to the biofilms, the removal ratio decreased by 24% with a rise of Cr(VI) concentration from 8.6 to 43 mg L-1. The prolongation of hydraulic retention time could promote the performance of Cr(VI) biosequestration. The chemical form of Cr deposited as the product of bio-reduction was confirmed as Cr(OH)3·H2O and other complexes of Cr(III). Our work demonstrated the efficacy of molasses for in situ sequestration of Cr(VI) under the dynamic flow condition and provide some useful information for Cr-contaminated groundwater remediation.

Investigation and prediction of the biotoxicity of Cu2+ to Chlorella vulgaris: modification of the biotic ligand model.

The increased copper ion (Cu2+) concentrations in aquatic ecosystem significantly influence the environmental quality and ecosystem safety, while information on the Cu2+ biotoxicity to aquatic microorganisms and the models for biotoxicity prediction are still unclear. In this study, the toxicities of Cu2+ to Chlorella vulgaris under different environmental conditions (e.g., Na+, K+, Ca2+, Mg2+, pH, and dissolved organic matter) were explored, with the experimental results in comparison with those predicted by the biotic ligand model (BLM). Results showed that increased Cu2+ concentration caused obvious toxicities to C. vulgaris, whereas the commonly occurring cations and dissolved organic matters can protect the metabolism system of C. vulgaris. The presence of extracellular polymeric substances (EPS) matrix can alleviate the biotoxicity via increasing the surface biosorption but decreasing cell internalization of Cu2+ in C. vulgaris. Due to the presence of EPS matrix, the experimental biotoxicity results under each condition were significantly lower than those predicted by the BLM model, which was thus modified via taking the EPS matrix as the supplement of allochthonous organic matters. After that, the modified BLM was characterized with a higher degree of precision and can be used in natural waters for biotoxicity prediction. Results obtained can enhance our insights into the ecological effects and biotoxicity prediction of heavy metals in natural aquatic ecosystems.

Association of weight-adjusted-waist index with asthma prevalence and the age of first asthma onset in United States adults.

Objective: The objective of this study was to assess whether the weight-adjusted-waist index(WWI) is associated with the prevalence of asthma and age when first asthma onset appears in US adults. Methods: For analysis we selected participants from the National Health and Nutrition Examination Survey(NHANES)database between 2001 and 2018. A dose-response curve was calculated using logistic regression,subgroup analysis,and a dose-response curve. Results: The study included 44480 people over the age of 20,including 6061 reported with asthma, and the increase in asthma prevalence was 15% associated with each unit increase in the WWI, after adjusting for all confounders(odds ratio(OR)=1.15,95% CI:1.11,1.20). The sensitivity analysis was performed by trichotomizing the WWI, and compared to the lowest tertile, the highest tertile WWI group displayed a 29% increase in asthma prevalence(OR=1.29,95% CI:1.19,1.40). A nonlinear correlation was found between the WWI index and the risk of asthma onset, with a threshold saturation effect indicating an inflection point of 10.53 (log-likelihood ratio test, P<0.05), as well as a positive linear correlation with age at first asthma onset. Conclusions: A higher WWI index was associated with an increased prevalence of asthma and an older age of first asthma onset.

Spatiotemporal distribution, partitioning behavior and flux of per- and polyfluoroalkyl substances in surface water and sediment from Poyang Lake, China.

Thirty-five legacy and emerging per- and polyfluoroalkyl substances (PFAS) were analyzed in surface water and sediments collected from Poyang Lake, the largest freshwater lake in China. The Æ©PFAS concentrations ranged from 23 to 1000 ng/L in water dissolved phase, 1.3-9.8 ng/L in suspended particulate matters, and 0.26-2.9 ng/g dry weight in sediments. Short-chain and emerging PFAS were predominant in surface water and sediments, rather than legacy perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Hexafluoropropylene oxide dimer/trimer acid (HFPO-DA/TA), 6:2 and 8:2 chlorinated polyfluorinated ether sulfonic acids (6:2 and 8:2 Cl-PFESAs), 6:2 fluorotelomer sulfonate (6:2 FTS), and sodium p-perfluorous nonenoxybenzene sulfonate (OBS) were detected in all samples, indicating that these emerging PFAS have been widely produced and used in this region. The high concentrations of HFPO-DA/TA, 6:2 FTS, 6:2, 8:2 Cl-PFESAs, and OBS in sediments and their higher water-sediment distribution coefficients than those of predecessors (PFOA or PFOS) suggest that lake sediments could be an important long-term sink for these emerging alternatives. The positive matrix factorization model demonstrated that food packaging and textile treatments (50%) and fluoropolymer manufacturing (26% for alternative sources and 8.2% for legacy sources) were the two major sources of PFAS in Poyang Lake. The influx and outflux of total PFAS in Poyang Lake were 9.0 and 12.8 ton/year, respectively, and the OBS flux was estimated for the first time. The results provide insights into the environmental behavior and fate of emerging PFAS in freshwater ecosystems.

Metagenomics-based antibiotic resistance genes diversity and prevalence risk revealed by pathogenic bacterial host in Taihu Lake, China.

In recent decades, antibiotics and antibiotic resistance genes (ARGs) have been regarded as emerging pollutants. In Taihu Lake, as a typical representative of freshwater system in China, the ARGs occurrence and abundance was of great importance for ecological risk control and public health protection. In this research, high-throughput sequencing and metagenomics technique were used to investigate the seasonal ARGs profile in overlying water and sediment at typical area of Taihu Lake. Besides, taxonomy pattern of ARGs host bacteria and potential pathogens were identified. The results showed that 33 ARG subtypes and 11 ARG types were detected in research area, among which bacitracin, multidrug and sulfonamides resistance gene were with the highest abundance. The relative abundance of ARGs in overlying water and sediment ranged from 1.68 to 661.05 ppm and from 1.93 to 49.47 ppm, respectively. ARG host (18 bacteria genus) were identified and annotated, among which Clostridium botulinum, Pseudomonas aeruginosa and Klebsiella pneumonia were pathogenic bacteria. The pathogens were mostly detected at Xukou Bay in spring and fall, which might be caused by the inlet water from aquaculture area of Yangcheng Lake. Pseudomonas was the most abundant ARGs host (ant2ib, baca, bl2d_oxa2,mexb, mexf, mexw and oprn), which may facilitate the propagation of ARGs in freshwater system.

Characterization and biological evaluation of a novel silver nanoparticle-loaded collagen-chitosan dressing.

Effective coverage and protection is a priority in wound treatment. Collagen and chitosan have been widely used for wound dressings due to their excellent biological activity and biocompatibility. Silver nanoparticles (AgNPs) have a powerful antibacterial effect. In this study, a macromolecular and small-molecular collagen mixed solution, a macromolecular and small-molecular chitosan mixed solution were prepared, and a silver nanoparticle-loaded collagen-chitosan dressing (AgNP-CCD) has been proposed. First, the effects of a collagen-chitosan mixed solution on the proliferation of human umbilical vein endothelial cells and the secretion of cytokines were evaluated. Then, the characteristics and antibacterial effects of the AgNP-CCD were tested, and the effects on wound healing and the influence of wound cytokine expression were investigated via a deep second-degree burn wound model. The results showed that at the proper proportion and concentration, the collagen-chitosan mixed solution effectively promoted cell proliferation and regulated the levels of growth factors (vascular endothelial growth factor [VEGF], epidermal growth factor [EGF], platelet-derived growth factor [PDGF], transforming growth factor [TGF-ß1], basic fibroblastic growth factor [bFGF]) and inflammatory factors (TNF-α, IL-1ß, IL-6, IL-8). Moreover, AgNP solutions at lower concentrations exerted limited inhibitory effects on cell proliferation and had no effect on cytokine secretion. The AgNP-CCD demonstrated satisfactory morphological and physical properties as well as efficient antibacterial activities. An in vivo evaluation indicated that AgNP-CCD could accelerate the healing process of deep second-degree burn wounds and played an important role in the regulation of growth and inflammatory factors, including VEGF, EGFL-7, TGF-ß1, bFGF, TNF-α and IL-1ß. This AgNP-CCD exerted excellent biological effects on wound healing promotion and cytokine expression regulation.

[Principles of "ecological living water" to purify sewage and its application in black and smelly water treatment of Yangzhou].

To explore the fundamental way of black and odorous water treatment, based on the study of the purification function of natural water body and the analysis of root cause and direct cause of black and odorous water body, we elaborated the scientific connotation and ecological function of "ecological living water", and fully revealed the scientific principle and technical advantages of "ecological living water" for sewage treatment. "Ecological living water" was the original ecological water control in situ. Through the rapid water reaeration, the micro-ecosystem of living water was created. Meanwhile, with the support of micro-speed circulating water, the continuous and efficient purification was realized. The practice of black and odorous water treatment in Yangzhou showed that, 3-5 days after the treatment of "ecological living water", the black and odorous water was completely eliminated and transformed into "green water". 15-20 days after the treatment, water quality reached the national surface water class 3 water standard. Therefore, "ecological living water" may be a kind of sustainable water control technology system with investment of less resources and equipment, fast pollution control speed, low operation cost, good water control effect and both symptoms and treatment.

Effect of wheat-maize straw return on the fate of nitrate in groundwater in the Huaihe River Basin, China.

Straw return is becoming a routine practice in disposing of crop residues worldwide. However, the potential effect of such operation on the chemistry of local groundwater is not well documented. Here, shallow groundwater in an area where wheat-maize straw return is practiced was analyzed, and the seasonal changes in the nitrate concentration and the isotope compositions of NO3- and H2O were determined along two flow paths. Measured δD and δ18O in waters indicated that the groundwater was mainly recharged by atmospheric precipitation, while measured δ15N and δ18O in nitrate suggested that the sources for groundwater NO3- included urea fertilizer, soil nitrogen, and sewage/manure. Reduced NO3- concentrations coincided with an enrichment of organic matter in the groundwater of the straw return area, revealing an environmental condition that facilitates nitrate reduction, whereas increased δ15N-NO3- and δ18O-NO3- along the flow path suggested the occurrence of denitrification. Further analyses showed that, compared to the cases in the absence of straw return, as much as 80% and 90% of groundwater nitrate was removed in low and high water seasons in the straw return area, pointing to a potential positive effect of straw return to groundwater quality.

Illumina sequencing-based analysis of sediment bacteria community in different trophic status freshwater lakes.

Sediment bacterial community is the main driving force for nutrient cycling and energy transfer in aquatic ecosystem. A thorough understanding of the community's spatiotemporal variation is critical for us to understand the mechanisms of cycling and transfer. Here, we investigated the sediment bacterial community structures and their relations with environmental factors, using Lake Taihu as a model system to explore the dependence of biodiversity upon trophic level and seasonality. To combat the limitations of conventional techniques, we employed Illumina MiSeq Sequencing and LeFSe cladogram to obtain a more comprehensive view of the bacterial taxonomy and their variations of spatiotemporal distribution. The results uncovered a 1,000-fold increase in the total amount of sequences harvested and a reverse relationship between trophic level and the bacterial diversity in most seasons of a year. A total of 65 phyla, 221 classes, 436 orders, 624 families, and 864 genera were identified in the study area. Delta-proteobacteria and gamma-proteobacteria prevailed in spring/summer and winter, respectively, regardless trophic conditions; meanwhile, the two classes dominated in the eutrophication and mesotrophication lake regions, respectively, but exclusively in the Fall. For LEfSe analysis, bacterial taxon that showed the strongest seasonal or spatial variation, majority had the highest abundance in spring/summer or medium eutrophication region, respectively. Pearson's correlation analysis indicated that 5 major phyla and 18 sub-phylogenetic groups showed significant correlation with trophic status. Canonical correspondence analysis further revealed that porewater NH4+ -N as well as sediment TOM and NOx -N are likely the dominant environmental factors affecting bacterial community compositions.

Bone marrow-derived mesenchymal stem cell transplantation ameliorates oxidative stress and restores intestinal mucosal permeability in chemically induced colitis in mice.

BACKGROUND: Ulcerative colitis (UC) can be viewed as an autoimmune disease. Bone marrow-derived mesenchymal stem cells (MSCs) with its regenerative, cellular multi-lineage and immunomodulatory abilities can influence the repair of damaged tissues in UC. This study investigated the effects of MSCs transplantation on the mice intestinal barrier in response to oxidative stress injury. METHODS: Colitis was induced by daily consecutive administration of 5% dextran sulfate sodium (DSS) solution for 7 days. Male murine MSCs were isolated and transplanted into female mice via injection in the tail vein. Serum and colon specimens were collected at 12 h, 24 h, 3 d, 7 d and 14 d after injection. Serum levels of D-lactate (D-LAC), diamine oxidase (DAO), colonic levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were quantified. The SRY protein of the male sex determinant gene expression and E-cadherin were also ascertained intracellularly. RESULTS: Three days after receiving male MSCs transplantation, SRY protein expression was detected. The quantity increased on successive days. Serum levels of D-LAC and DAO, colonic MDA and SOD normalized in a shorter time period compared to controls (p<0.05). Not surprisingly, histological regeneration of tissue and E-cadherin expression in the colon of MSCs transplanted mice also occurred in a shorter time period than controls. CONCLUSIONS: Transplanted MSCs restored mucosal permeability, and minimized oxidative stress related injury.

Poly(allylamine)-encapsulated water-soluble CdSe nanocrystals.

Water-soluble CdSe nanocrystal/poly(allylamine) clusters with sizes ranging between 50 and 200 nm were prepared using 3-amino-1-propanol as a compatibilizing agent. Photoluminescence (PL) quantum yields (QY) up to 20% were achieved in water without the need to clad these CdSe nanocrystals (NCs) with higher band gap inorganic layers. The polymer-to-nanocrystal ratio plays an important role in the internal structure and stability of these polymer/NC clusters, as determined by static and dynamic light scattering in conjunction with PL studies. These results were modeled by using an effective-mass approximation and perturbation theory on the change in dielectric constant of the immediate NC environment. The time evolution of the average cluster radius of gyration and hydrodynamic radius revealed that a higher polymer-to-NC ratio leads to increased PL stability and QY. This is a result of a denser cluster configuration, which affords improved NC passivation. Increasing the ionic strength results in greater nanocluster compaction and higher PL QYs. Decreasing the pH value below 12 resulted in dramatic reduction in PL brightness, despite cluster densification, due to partial ionization and dissolution of the amine-based NC surface-capping agents.

[Study of the Raman spectrum of CCl4 Fermi resonance].

Fermi resonance is a very common phenomenon in molecule vibration spectra, especially in polyatomic molecule with complex structure. Fermi resonance appears when a fundamental vibration frequency lies closely to an overtone or combination frequencies. One can observe two peaks coming from Fermi resonance and the energy transfer also occurs between the two peaks. Fermi resonance phenomenon appears in both infrared spectrum and Raman spectrum. The Raman spectrum of CCl4 was measured. The frequency separation between the two peaks in a Fermi resonance doublet was observed and the integrated intensities were calculated with the software of Origin Pro 7.5. Fermi resonance interaction was caused by the CCl4 C-Cl f-symmetrical stretching fundamental nu3 coupling. The combination frequency (nu1 + nu4) of C-Cl a1-symmetrical stretching nu1 and band C-Cl2 f-symmetrical bending nu4 was calculated. Based on Bertran's theory, Fermi coupling coefficient W was calculated and the theoretical value nu3(0) of nu3 was estimated. The present article provided good reference for better understanding of the relationship between molecular vibration frequency and molecular structure.

Redox-assisted asymmetric ostwald ripening of CdSe dots to rods.

The redox-assisted asymmetric Ostwald ripening of dots to rods was observed upon annealing a concentrated dispersion of CdSe nanocrystals (NCs) containing 0.1 M CdCl2 in 3-amino-1-propanol (APOL)/H2O (v/v = 9/1) at 135 degrees C. Transmission electron microscopic investigation, along with UV-vis and photoluminescence results, revealed that, while the length of these NCs increased upon annealing, their diameter remained constant. The surface oxidation of NC Se atoms to SeO2 and its subsequent dissolution into the basic APOL/H2O mixture as SeO32- was found instrumental for such dot-to-rod transformation. The amine-assisted SeO2 reduction to Se0 (as confirmed by X-ray photoelectron spectroscopy and X-ray diffraction results) provides the Se source for further NC growth. The preferential growth along the c-axis leads to the formation of rods with zinc blende CdSe structure at its growing ends, due to the low-temperature growth conditions.

Amine-assisted facetted etching of CdSe nanocrystals.

The treatment of CdSe nanocrystals (NCs) in a 3-amino-1-propanol (APOL)/water (v/v = 10:1) mixture at 80 degrees C in the presence of O(2) causes them to undergo a slow chemical etching process, as evidenced by spectroscopic and structural investigations. Instead of the continuous blue shift expected from a gradual decrease in NC dimensions, a bottleneck behavior was observed with distinct plateaus in the peak position of photoluminescence (PL) and corresponding maxima in PL quantum yield (i.e., 34 +/-7%). It is presently argued that such etching behavior is a result of two competitive processes taking place on the surface of these CdSe NCs: (i) oxidation of the exposed Se-sites to acidic SeO(x)() entities, which are readily solubilized in the basic APOL/H(2)O mixture, and (ii) coordination of the underlying Cd-sites with both amines and hydroxyl moieties to temporally impede NC dissolution. This is consistent with the HRTEM results, which suggest that the etched NCs adopt pyramidal morphologies with Cd-terminated facets (i.e., (0001) bases and either {011} or {21} sides) and account for the apparent resistance to etching at the plateau regions.

Clonal expansion T cells identified in acute monoblastic leukemia by CDR3 size analysis of TCR V beta repertoire using RT-PCR and genescan.

OBJECTIVE: To investigate the distribution and clonality of T cell receptor (TCR) V beta repertoire in patients with acute monoblastic leukemia (AML-M5). METHODS: Expression of the TCR V beta repertoire was analyzed using reverse transcription-polymerase chain reaction (RT-PCR), which amplified the complementarity determining region 3 of 24 TCR V beta genes in peripheral blood from 9 cases with acute myclogenous leukemia subtype 5 or acute monoblastic leukemia (AML-M5). PCR products were further studied by genescan analysis to identify T cell clonality. RESULTS: Expression of 1-10 V beta subfamilies was found in samples from 9 patients. Genescan analysis showed that some V beta subfamily products from 8 of 9 cases contained an oligoclonal peak. Oligoclonal T cells of the V beta 2 subfamily could be found in 6 patients with AML-M5. CONCLUSIONS: T cell clonality expansion was found in AML-M5 cases and were tendentious in the V beta 2 subfamily, suggesting a the specific immune response for leukemia cell (M5) associated antigen and may display antileukemia activity.

[Study on clonal proliferation of TCR Vbeta subfamily T cells induced by AML-M(2a) cells in vivo and in vitro].

To observe the expression and clonal expansion of TCR Vbeta subfamily T cells induced by AML-M(2a) cells in vivo and in vitro, complementary determining region 3 (CDR3) of TCR beta with variable region genes was amplified by using RT-PCR in both peripheral blood mononuclear cells (PBMNC) and T cells from mixed lymphocyte and tumor culture (MLTC) from four AML-M(2a) patients. The positive products were further analyzed to identify the clonality of T cells by genescan. The results showed that the similarity distribution of TCR Vbeta subfamily T cells was found Vbeta in PBMNC and MLTC. One or two clonality expansions of T cells could be found in predominant TCR Vbeta subfamily T cells induced by A ML-M2a cells from 3 cases in vivo and in vitro. It was concluded that clonal expansion of TCR Vbeta subfamily T cells stimulated selectively by AML-M(2a) cells may be a specific immune response of patient's T cells to AML-M(2a) cells associated antigen. The clonal proliferation of TCR Vbeta subfamily T cells were affected somewhat by environmental difference in vivo and in vitro.

[The distribution feature of TCR Vbeta repertoire in peripheral blood T cells from patients with Ph(+) and Ph(-) CML].

To investigate the T cell distribution characters of TCR Vbeta repertoire in Ph(+) and Ph(-) CML. The 24 subfamilies of the TCR Vbeta genes were amplified in peripheral blood T cells from 13 patients with CML (Ph+ b3a2, 5 cases; Ph+ b2a2, 5 cases; Ph(-), 3 cases) by RT-PCR, to analyze the usage of Vbeta subfamilies in different CML patients. The results showed that the expression pattern of Vbeta repertoire was different in normal individuals and in patients with CML which only have part of Vbeta subfamily T cells. 4 - 16 (mean 10.2) Vbeta subfamily T cells were detected in the Ph+ b3a2 CML, 8 - 11 (mean 8.8) Vbeta subfamily T cells in the Ph(+) b2a2 CML and 5 - 6 (mean 5.7) in Ph(-) CML. Moreover, the expression of Vbeta subfamily T cells was different among these three types CML.Vbeta10 and Vbeta16 were detected in the all cases with Ph(+) b3a2 and Ph(+) b2a2 CML, whereas Vbeta9 and Vbeta22 could be found in the most cases with Ph(+) b3a2 CML or Vbeta24 and Vbeta8 in Ph(+) b2a2 CML. In patients with Ph(-) CML, Vbeta24 were detected in all samples, and Vbeta9, Vbeta10, Vbeta13 and Vbeta22 were found in the most cases. The results suggest that skew distribution of TCR Vbeta subfamily T cells was existed in peripheral blood of Ph(+) and Ph(-) CML patients. The selected usage of TCR Vbeta is different in various types of CML patients. It may relate to difference of CML cells associated antigen and individual special immunity reaction.

[Advance of Research on Treatment of Donor Lymphocyte Infusions in Relapse of Hematologic Malignancies after Allogeneic Bone Marrow Transplantation]

The applications of allogeneic bone marrow transplantation (allo-BMT) are limited by the high risk of relapse with primary malignancy. The newly adaptive immunotherapy with donor lymphocyte infusions (DLI) can induce an effective graft-versus-leukemia (GVL) reaction leading to molecular remission and prolonged disease free survival in the majority of patients with relapse of CML and some other hematologic malignancies. Little is known about the mechanisms and the kinetics of GVL, however, increasing evidences show that in the case of existence of chimerism the mature donor T lymphocytes are activated by the specific leukocyte artigen presented in the surface of host antigen presenting cells (APC), resulting in exclusively elimination of leukocyte. Undesired side-effects are the development of graft-versus-host disease (GVHD) and the occurrence of pancytopenia in some patients. Infusions with selective T lymphocytes and G-CSF-mobilized peripheral blood stem cells (PBSC) are the promising treatment of DLI for more patients.