An injectable, chitosan-based hydrogel prepared by Schiff base reaction for anti-bacterial and sustained release applications.

Injectable hydrogels, providing sustained release as implanted materials, have received tremendous attention. In this study, chitosan-based hydrogels were prepared via Schiff base reaction of the aldehyde groups on Poly(NIPAM-co-FBEMA) and the amine groups on chitosan. Owing to the dynamic covalent linkage, the SC/PNF hydrogels exhibit pH-responsive, reversible sol-gel transition, injectable, and self-healing capacity. The mechanical strength of SC/PNF hydrogels can be operated simply by switching the composition or solid content of Poly(NIPAM-co-FBEMA) copolymers. Rheological analyses, including frequency sweeps, strain sweep scanning, and dynamic time sweeps, were employed to demonstrate the relationship between storage modulus (G'), loss modulus (G″), and composition of the SC/PNF hydrogels. In vitro release behaviors reveal that vancomycin-loaded SC/PNF hydrogel could contribute to both the initial burst release (over 1000 ppm within 4 h) and the sustained release (3000 ppm for at least 30 days). Pristine SC/PNF hydrogel holds good biocompatibility toward L929 cells and S. aureus that it degrades as incubated with S. aureus. However, vancomycin-wrapped SC/PNF hydrogel possesses a rapid bacterial-killing effect with a clear inhibition zone. In short, the SC/PNF hydrogels deliver not only sustainable release ability but also tunable physical properties, which are expected to be an outstanding candidate for non-invasive, anti-infection applications.

[Influence of Impervious Surface Roughness on Accumulation and Erosion of Urban Non-Point Source Particles].

At present, there are few reports about how impervious surface microstructure characteristics affect the runoff output process of street dust. Based on field observations of 12 rainfall events, this study quantified the microstructure characteristics of impervious surfaces by structural depth (roughness) and analyzed the correlation between roughness and accumulation characteristics of street dust on sunny days as well as scouring characteristics in rainy days. The results show that the roughness of the underlying surface notably affects dust accumulation on sunny days and scouring in rainy days. The correlation between roughness and street dust accumulation (r=0.664, P<0.01) was enhanced on sunny days, and the correlation between roughness and street dust erosion (r=0.527, P<0.01) was enhanced by rainfall. The correlation of street dust accumulation and roughness of each particle size segment increased as particle size increased (0.529 ≤ r<0.757), and the correlation between street dust scouring amount and roughness decreased as particle size increased (0.603 > R > 0.209). By establishing the linear regression model of roughness and rainfall, the cumulative pollution load of TSS in rainfall runoff can be well predicted. The effects of roughness and rainfall on the cumulative load of grain sizes<20 µm and >250 µm are significant. These results elucidate the role of roughness and rainfall analysis in predicting surface runoff pollution load characteristics, which can provide new information for predicting and evaluating urban non-point source pollution.

[Transition of Particulate Pollutant in the Parcel-based Catchment of Sponge City].

Most sponge city constructions in China are carried out in urban parcel-based catchments, and the quality and quantity of surface runoff can be controlled by several low impact development (LID) facilities. However, there are few reports on the generation and control of urban diffuse pollution. In this study, two areas with different hardening rates were compared to analyze the load conditions during the accumulation-wash-off-transport process of particulate pollutants. The results showed that the road surface in the catchment was the main underlying surface that the particulate pollutants contributed to. The road dust accumulation in the medium hardening rate (61.1%) and high hardening rate (73.6%) plots accounted for 88.4% (2.22-12.51 g ·m-2) and 90.1% (4.99-33.43 g ·m-2) of the catchment area unit, respectively. The contribution to the suspended solids (SS) load of runoff was 91.7% (0.97-7.34 g ·m-2) and 90.5% (0.92-18.77 g ·m-2), respectively. The SS load of road runoff accounted for approximately 95.2% and 83.1%, respectively. The pollution load (SS) after treatment by the LID facilities was approximately 24.0% and 40.2% of the surface runoff, respectively. The particle size distribution of road dust during the accumulation and wash-off processes was>150 µm, while that in surface and output runoff was <50 µm. With the increase in the impervious area, the distribution of finer particles (<105 µm) in the process of accumulation and wash-off increased (24.4%, 106.4%), while the distribution of particles <50 µm in road runoff decreased (12.4%). The particle size distribution of the accumulated, washed dust, and the rain runoff on the roof were roughly similar to those on the road. However, compared to the particle size distribution of road dust, in the accumulation and wash-off processes, the coarser particles (>1000 µm) of the medium hardening rate plot and the particles of size 250-450 µm and <45 µm of the high hardening rate plot increased significantly (>1000 µm: 58.1%, 108.5%; 250-450 µm: 72.9%, 41.8%; <45 µm: 59.2%, 64.8%). The results revealed the entire distribution process (accumulation-wash-off-transport) of particulate pollutants and the effect of LID facilities on the total SS pollution load of the catchment, which can provide an important reference for the scientific assessment of the project performance of LID installation in urban parcel-based catchments.

[Influence of Pervious/Impervious Pattern on Runoff and Pollution in Parcel-based Catchment].

Determining the influence of pervious/impervious underlying surface pattern (composition, position, proportion, etc.) on the generation capacity of surface runoff and pollution in the urban parcel-based catchment could aid in alleviating the urban waterlogging and control non-point source pollution significantly. Landscape metrics were used to analyze the relationship between the characteristics of pervious/impervious underlying surface pattern and total runoff (Q) and the cumulative load of dissolved pollutants (Ld) and particulate pollutants (Lp). The results showed that: ① For the metrics of fragmentation, the patch density (PD) was positively correlated with Q and Ld. and largest patch index (LPI) was negatively correlated with them. Especially, the PD exhibited a significantly positive correlation with Ld(r=0.59, P<0.05, calculated in COD). However, the LPI exhibited a significantly negative correlation with Ld (r=-0.60, P<0.05, calculated in COD). ② For the metrics of complexity, landscape shape index (LSI) was positively correlated with Q and Lp, and mean shape index (MSI) was negatively correlated with them. Especially, the LSI exhibited a significantly positive correlation with Lp (r=0.61, P<0.05, calculated in TP) significantly. However, the MSI exhibited a significantly negative correlation with Lp (r=-0.62, P<0.01, calculated in TP) significantly. ③ For the metrics of vergence, the split index (SPLIT) was positively correlated with Q and Ld, and the cohesion index (COHESION) was negatively correlated with them. The COHESION exhibited a significantly negative correlation with Ld(r=-0.59, P<0.05, calculated in COD), whereas the SPLIT exhibited a significantly positive correlation with Ld (r=0.6, P<0.05, calculated in COD). ④ In the planning on the distribution and pattern of pervious surface under small-scale catchment, it is suggested that the scattered small-regular patches should be transformed to large-irregular patches or patch group. The relationship of the fragmentation, complexity, and vergence of pervious/impervious surface, with the runoff generation, and pollution output in parcel-based catchment was analyzed, which provided a new method for rainfall runoff and pollution control by considering rational allocation of LID facilities in terms of its pattern characteristics (area, distance, shape, etc.).

Increased serum malondialdehyde levels are associated with grey matter volume loss in patients with non-alcoholic cirrhosis.

BACKGROUND: Grey matter volume (GMV) loss has been observed in patients with non-alcoholic cirrhosis, but the underlying mechanisms are unknown. Oxidative stress (OS) is a recognized feature and systemic phenomenon of cirrhosis. However, little is known about whether OS is associated with GMV loss in cirrhosis. This study aimed to assess the relationship between oxidative damage and GMV loss in patients with non-alcoholic cirrhosis. METHODS: Thirty-four patients with non-alcoholic cirrhosis and 27 age- and sex-matched healthy controls were enrolled in this prospective study. All subjects underwent brain magnetic resonance imaging (MRI), and voxel-based morphometry (VBM) was performed to assess normalized global GMV. As an OS marker, serum malondialdehyde (MDA) levels were determined in all subjects. In the patient group, a correlation analysis was used to investigate the relationship between serum MDA levels and normalized global GMV. RESULTS: Compared with healthy controls, cirrhotic patients displayed a significant decrease in normalized global GMV and a significant increase in serum MDA levels. In the patient group, serum MDA levels were negatively correlated with normalized global GMV adjusted for age, sex and Child-Pugh class. CONCLUSIONS: Increased serum MDA levels were associated with GMV loss in patients with non-alcoholic cirrhosis, suggesting that oxidative damage may be involved in GMV loss observed in cirrhotic patients.

[Evaluation of Effect of Urban Non-point Source Pollution Control on Porous Asphalt-Bio-retention Combined Roads].

Different combinations of low impact development (LID) technologies can be applied for control of urban non-point source pollution. There are currently few evaluations of urban non-point source pollution and pollution load reduction based on a combination of porous asphalt and bio-retention. Taking Shenzhen International Low Carbon City as an example, road-deposited sediments were collected prior to and after rainfall events. Runoff was monitored under six typical rainfall events, from porous asphalt and the inlet/outlet of bio-retention. Through analysis of changes in the process of "build-up-wash-off-transport" of pollutant loads, the average build-up of road-deposited sediments in the study area was found to be (15.80±3.79) g·m-2; the mass percentage of road-deposited sediments (size>250 µm) was approximately 65.14%. The average wash-off percentage of six different intensity rainfall events was 17.15%, and road-deposited sediments (size<105 µm) were carried by 62.71%-74.94%. The average pollution loads of surface runoff pollutants SS, TN, and TP were 2.02, 0.025, and 0.0013 g·m-2, respectively. The removal rates of SS, TN, and TP through porous asphalt under infiltration and filtration were 70.26%, 46.29%, and 19.27%, respectively. The secondary purification removal rates of runoff water in bio-retention were 85.25%, 20.22%, and 70.27%, respectively. Pollutant loads into Dingshan River totaled 0.08, 0.011, and 0.0003 g·m-2, representing 4.05%, 43.47%, and 24.39% of runoff. The combination thus had a significant effect on runoff purification. Through quantitative research on the formation of non-point source pollution, this paper provides a scientific basis for estimating pollution loads of urban non-point source pollution and evaluating the performance of LID projects. It makes suggestions for the popularization and application of LID and sponge city design in China.

Intra-arterial delivery of superparamagnetic iron-oxide nanoshell and polyvinyl alcohol based chemoembolization system for the treatment of liver tumor.

A superparamagnetic iron oxide (SPIO) nanoshell and polyvinyl alcohol (PVA) based chemoembolization system for anti-cancer drug doxorubicin (DOX) delivery has previously been presented. We have also previously confirmed the feasibility and safety of this multifunctional system for carrying both DOX and SPIO nanoparticles in vitro. However, the pharmacokinetic and the therapeutic efficacy of this novel drug-delivery system in vivo is not yet clear, and as such was the subject of this study. A rabbit liver tumor model was utilized, whereby the tumors were targeted by SPIO/DOX/PVA composite infused via a catheter into the hepatic arteries which supplying blood to the tumor. The result was compared to saline, DOX+PVA, or SPIO/DOX infusion alone. SPIO/DOX/PVA displayed sustained chemotherapeutic agent release into the tumor. In comparison to other treatment groups, tumor growth rate was significantly slowed down by SPIO/DOX/PVA with a smaller tumor volume and a prolonged survival time of the experimental rabbits. Liver function results demonstrated SPIO/DOX/PVA has no apparent toxicity to the normal liver. Pharmacokinetic studies and histological evaluations in SPIO/DOX/PVA group revealed that long-term retention and drug release within the tumor associated with SPIO/DOX/PVA therapy, and thereafter induced significantly enhanced tumor necrosis and apoptosis. We conclude SPIO/DOX/PVA provides a highly effective therapeutic strategy for management of liver tumors.