Toxicity evaluation of a heavy-metal-polluted river: Pollution identification and bacterial community assessment.

The Salt River is an important urban river in Kaohsiung, Taiwan. In this study, the source identification and risk and toxicity assessment of the heavy-metal-contaminated sediments in the Salt River were investigated. The geo-accumulation index (Igeo), enrichment factor (EF), sediment quality guidelines (SQGs), potential ecological risk index (RI), pollution load index (PLI), and toxic units (TU) were applied to determine effects of heavy metals on microbial diversities and ecosystems. Results from the ecological and environmental risk assessment show that high concentrations of Zn, Cr, and Ni were detected in the midstream area and the sum of toxic units (ΣTUs) in the midstream (7.2-32.0) is higher than in the downstream (14.0-19.7) and upstream (9.2-17.1). It could be because of the continuous inputs of heavy-metal-contained wastewaters from adjacent industrial parks. Results also inferred that the detected heavy metals in the upstream residential and commercial areas were possibly caused by nearby vehicle emissions, non-point source pollution, and domestic wastewater discharges. Results of metagenomic assays show that the sediments contained significant microbial diversities. Metal-tolerant bacterial phyla (Proteobacteria: 24.4%-46.4%, Bacteroidetes: 1.3%-14.8%, and Actinobacteria: 2.3%-11.1%) and pathogenic bacterial phyla (Chlamydiae: 0.5%-37.6% and Chloroflexi: 5.8%-7.2%) with relatively high abundance were detected. Metal-tolerant bacteria would adsorb metals and cause the increased metal concentrations in sediments. Results indicate that the bacterial composition in sediment environments was affected by anthropogenic pollution and human activities and the heavy-metal-polluted ecosystem caused the variations in bacterial communities. PRACTITIONER POINTS: Microbial community in sediments is highly affected by heavy metal pollution. Wastewaters and vehicle traffic contribute to river sediments pollution by heavy metals. Proteobacteria, Bacteroidota, and Actinobacteria are dominant heavy-metal-tolerant bacterial phyla in sediments. Toxicity assessment is required to study risk levels of heavy-metal contained sediments.

Toxicity determination, pollution source delineation, and microbial diversity evaluation of PAHs-contaminated sediments for an urban river.

The Feng-Sang River is a metropolitan river in Kaohsiung City, Taiwan. In this study, Feng-Sang River sediments were analyzed to investigate the distributions and sources of polycyclic aromatic hydrocarbons (PAHs). The Sediment Quality Guidelines (SQGs), potentially carcinogenic PAHs (TEQcarc ), and toxic equivalence quotient (TEQ) were applied to evaluate influences of PAHs on ecosystems and microbial diversities. Results indicate that PAHs concentrations varied between seasons and locations. The concentrations of ∑16 PAHs ranged from 73.6 to 603.8 ng/kg in dry seasons and from 2.3 to 199.3 ng/kg in wet seasons. This could be because of the flushing effect during wet seasons, which caused the movement and dilution of the PAH-contaminated sediments. Diagnostic ratio analysis infers that high PAHs levels were generated by combustion processes and vehicle traffic, and results from multivariate descriptive statistical analysis also demonstrate that the vehicular traffic pollution could be the major emission source of PAHs contamination. Comparisons of PAHs with SQGs indicate that PAHs concentrations in sediment were below the effects range low (ERL) values, and thus, the immediate threat to organisms might not be significant. The diagnostic ratio analyses are effective methods for PAH source appointment. The metagenomic assay results imply that sediments contained essential microbial species with eminent diversity. The detected PAH-degrading bacteria (Desulfatiglans, Dechloromonas, Sphingomonas, Methylobacterium, Rhodobacter, Clostridium, and Exiguobacterium) played a key role in PAHs biotransformation, and Dechloromonas and Rhodobacter had a higher relative abundance. Results of microbial diversity analyses indicate that the contaminated environment induced the changes of governing microbial groups in sediments. PRACTITIONER POINTS: Diagnostic ratio analyses are effective methods for PAHs source appointment. Microbial composition in sediments are highly affected by anthropogenic pollution. Combustion and vehicle traffic contribute to urban river sediments pollution by PAHs. Dechloromonas and Rhodobacter are dominant PAHs-degrading bacteria in sediments.

Enhancement of the modulation bandwidth for GaN-based light-emitting diode by surface plasmons.

We have fabricated the surface plasmon (SP) coupled GaN-based nanorod LEDs with Ag nanoparticles (Nps), and demonstrate the enhancement of the optical modulation bandwidth by SPs. Compared with the LED without Ag Nps, the optical modulation bandwidth of the LED with Ag Nps increases by a factor of ~2 at 57 A/cm2. The photoluminescence (PL) and electroluminescence (EL) experimental results are consistent with each other, and both suggest the effective coupling between quantum wells (QWs) and SPs. Furthermore, the current dependent modulation frequency characteristics show that the QW-SP coupling can increase the modulation bandwidth, especially for LEDs with high intrinsic internal quantum efficiency (IQE). These findings will help to open a new solution to design the ultrafast LED light source for the application of the visible light communication.

Silk structure and degradation.

To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk.

Surface plasmon-enhanced nanoporous GaN-based green light-emitting diodes with Al2O3 passivation layer.

A surface plasmon (SP)-enhanced nanoporous GaN-based green LED based on top-down processing technology has been successfully fabricated. This SP-enhanced LED consists of nanopores passing through the multiple quantum wells (MQWs) region, with Ag nanorod array filled in the nanopores for SP-MQWs coupling and thin Al(2)O(3) passivation layer for electrical protection. Compared with nanoporous LED without Ag nanorods, the electroluminescence (EL) peak intensity for the SP-enhanced LED was greatly enhanced by 380% and 220% at an injection current density of 1 and 20A/cm(2), respectively. Our results show that the increased EL intensity is mainly attributed to the improved internal quantum efficiency of LED due to the SP coupling between Ag nanorods and MQWs.

Cloning and expression analysis of a novel high-mobility group box 2 homologue from Lampetra japonica.

High-mobility group box 2 (HMGB2) is a nonhistone architectural protein that plays important roles in many biological processes. In this study, we cloned a homologue of the HMGB2 from the lymphocyte-like cells of Lampetra japonica (L. japonica). Sequence analysis reveals that L. japonica HMGB2 contains two highly conserved motifs and shares more than 70 % identity with the homologues from other vertebrate species. Subsequently, Lj-HMGB2 was subcloned into the pET-28a(+) and pIRES2 AcGFP1-Nuc vector and expressed in Rosetta blue (DE3) and Hela cell lines, respectively. The recombinant L. japonica HMGB2 (rLj-HMGB2) with apparent molecular mass of 22 kDa was further purified by His-Bind affinity chromatography. Real-time quantitative PCR indicates that the expression level of Lj-HMGB2 was particularly up-regulated in intestines after challenged with lipopolysaccharide, while up-regulated in lymphocyte-like cells and heart after challenged with concanavalin A in vivo. In addition, rLj-HMGB2 could induce the generation of proinflammatory mediators in the activated human acute monocytic leukemia cell line (THP1), which suggested that Lj-HMGB2 may participate in the immune response of the lampreys.

[Effects of acupuncture on different acupoints in combination with rehabilitation on hemiplegic muscle spasticity in hemiplegia patients].

OBJECTIVE: To observe the clinical effect of hemiplegic muscle spasticity treated with acupuncture on different acupoints in combination with rehabilitation. METHODS: Ninety cases of post-stroke muscle spasticity were randomized into a corresponding and central axis acupuncture group (group A), a conventional acupuncture group (group B) and a rehabilitation group (group C), 30 cases in each one. In group A, the acupoints on the Governor Vessel were mainly selected, as well as those on Hand-Shaoyang meridian and Foot-Taiyang meridian. In group B, the conventional needling and rehabilitation training were applied in combination, of which, the acupoints were mainly from Hand and Foot-Yangming meridians, associated with the acupoints of Shaoyang meridian. In group C, only rehabilitation training was applied. The assessments according to modified Ashworth scale and CSS score were performed before treatment, after 2 weeks and 4 weeks treatment respectively. RESULTS: The level of modified Ashworth scale of the flexor of elbow and wrist was reduced apparently after treatment in group A as compared with that before treatment (P < 0.01). The level of modified Ashworth scale of the flexor of elbow was reduced apparently after treatment in group C as compared with that before treatment (P < 0.05). There was significant difference on the level change in modified Ashworth scale for the flexor of elbow between group A and group C after 4 weeks treatment (P < 0.05). CSS score decreased significantly in group A as compared with that before treatment (P < 0.01), the improvement after treatment in group A was apparent as compared with the other two groups (P < 0.01). CONCLUSION: The corresponding and central axis acupuncture can improve muscle tone of hemiplegic limb, which is superior to the effect achieved by the conventional acupuncture in combination with rehabilitation training and the simple rehabilitation training.

catena-Poly[[[diaqua-bis(8-hydroxy-quinoline N-oxide-κO)cobalt(II)]-µ-2,5-dimethyl-pyrazine 1,4-dioxide-κO:O] bis-(perchlorate)].

In the title complex, {[Co(C(6)H(8)N(2)O(2))(C(9)H(7)NO(2))(H(2)O)(2)](ClO(4))(2)}(n), the Co(II) ion lies on an inversion centre and is coordinated in a slightly distorted octa-hedral environment. The 2,5-dimethyl-pyrazine 1,4-dioxide ligand, which also lies on an inversion center, acts as a bridging ligand, linking symmetry-related Co(II) ions [Co⋯Co = 8.669 (3) Å] and forming one-dimensional chains along the b axis. In the crystal structure, these chains are linked by inter-molecular aqua-perchlorate O-H⋯O hydrogen bonds, forming two-dimensional layers which are in turn connected into a three-dimensional network via π-π stacking inter-actions between quinoline rings, with a centroid-centroid distance of 3.580 (3) Å. An intermolecular O-H⋯Cl inter-action is also present.

2,2'-(1,10-Phenanthrolin-2-ylimino)di-ethanol.

In the title compound, C(16)H(17)N(3)O(2), symmetry-related mol-ecules are linked into one-dimensional chains along the a axis by a combination of inter-molecular O-H⋯N and O-H⋯O hydrogen bonds and weak π-π stacking inter-actions with a centroid-centroid distance of 3.5494 (12) Å.

Tetra-µ-acetato-bis-{[9-(pyrazin-2-yl)-9H-carbazole]copper(II)}.

The title complex, [Cu(2)(CH(3)COO)(4)(C(16)H(11)N(3))(2)], lies on an inversion centre, with four acetate ligands bridging two symmetry-related Cu(II) ions and two monodentate 9-(pyrazin-2-yl)-9H-carbazole ligands coordinating each Cu(II) ion via the N atoms of the pyrazine rings, forming slightly distorted square-pyramidal geometries. There are weak π-π stacking inter-actions between the pyrrole rings of symmetry-related mol-ecules, with a centroid-to-centroid distance of 3.692 (2) Å.

[The effect of cold stress on DNA oxidative damage of lung in chicken].

AIM: To explore the influence of cold strss on DNA oxidative damage of lung in chicken. METHODS: Took 15-day-old healthy chicks as the experimental object, carried on the cold stress (12 +/- 1 degrees C) to process. Detected the change of the MDA content, SOD and GSH-Px activity of the lung, and performed KCl-SDS precipitation method and fluorescence detection method to identify the influence of cold strss on DNA-protein crosslinks (DPC) and DNA-DNA crosslinks (DDC) of lung cell in different time. RESULTS: The results were as follow: with the time lapsing during acute cold stress, MDA content gradually increased, the SOD and GSH-Px activity of the lung increased compared with their control group at each stress time point, and the lung cell DPC and DDC coefficient were all gradually increased with the time lapsing. CONCLUSION: Cold stress could bring about destruction in the lung tissue oxidation-antioxidant balance, and causes the oxidation damage of DNA.

[Effects of glutamine on the colon of mice subjected to colitis gravis].

AIM: To investigate the effects of glutamine on the colonic mucosa of mice subjected to colitis gravis. METHODS: 64 Kunming mice were divided randomly into 4 groups (n=16): healthy group: animals not subjected to colitis; model group: animals subjected to colitis gravis but without glutamine supplementation; low-Gln group: animals subjected to colitis gravis and with low dose of glutamine supplementation; high-Gln group: animals subjected to colitis gravis and with high dose of glutamine supplementation. Animals belonging to the control, the low-Gln, the high-Gin groups were subjected to coloclysis by HAC to be colitis gravis animals. When the models were established, the healthy and the control groups were given some isotonic Na chloride by intragastric administration. The low-Gln group and the high-Gln group were given the same volume but different concentration of glutamine(low-Gln group--2 mmol x Kg(-1) bw, high-Gln group--2 mmol x Kg(-1) bw) for 7 days. Then the mice were sacrificed, the pathohistological changes of the colon were observed, besides, the content of endotoxin in the blood serum, the level of counteracting oxidation and the activities of MPO of the colon tissue were determined. RESULTS: The glutamine lessened the pathological injures in the colon and relieved the step up of the content of endotoxin in the blood serum , the step down level of counteracting oxidation and the step up activity of MPO in the colon tissue, which were caused by colitis gravis. CONCLUSION: The glutamine can protect the colon of mice subjected to colitis gravis.

Dichlorido[1-(1,10-phenanthrolin-2-yl)-2-pyridone]copper(II).

In the title mononuclear complex, [CuCl(2)(C(17)H(11)N(3)O)], the Cu(II) ion is in a distorted square-pyramidal coordination environment. The crystal structure is stabilized by various π-π stacking inter-actions in which the benzene ring, a pyridine ring and the five-membered CuN(2)C(2) ring are involved. The centroid-centroid distances range from 3.5631 (15) to 3.5666 (16) Å.

Dichlorido[1-(1,10-phenanthrolin-2-yl)-2-pyridone]cadmium(II).

In the title mononuclear complex, [CdCl(2)(C(17)H(11)N(3)O)], the Cd(II) ion assumes a distorted trigonal-bipyramidal coordination geometry. The pyridone plane is twisted out of the 1,10-phenanthroline mean plane by 43.8 (3)°. In the crystal structure, short inter-molecular distances [3.627 (4)-3.671 (4) Å] between the centroids of the six- and five-membered Cd-containing rings suggest the existence of π-π inter-actions, which link the mol-ecules into stacks along the a axis.

Dichlorido[2,2'-(oxydimethyl-ene)dipyridine]copper(II).

In the title complex, [CuCl(2)(C(12)H(12)N(2)O)], the Cu(II) ion is coordinated in a distorted trigonal-bipyramidal environment. In the crystal structure, there is a weak π-π stacking inter-action between symmetry-related pyridine rings, with a centroid-to-centroid distance of 3.8134 (17) Å. In addition, there is relatively close contact between the pyridine ring π-system and a symmetry-related Cu(II) ion (Cu⋯centroid distance of 3.868 Å).

Dichlorido[2,2'-(oxydimethyl-ene)dipyridine]zinc(II).

In the title complex, [ZnCl(2)(C(12)H(12)N(2)O)], the Zn(II) atom is coordinated in a distorted trigonal-bipyramidal geometry by two Cl atoms, and one O atom and two N atoms from the 2,2'-(oxydimethyl-ene)dipyridine ligand. In the complex, the two pyridine rings make a dihedral angle of 15.44 (14)°. There is a weak inter-molecular π-π stacking inter-action between pyridine rings; the centroid-centroid distance is 3.8079 (17) Å.