Enhanced Detection in Droplet Microfluidics by Acoustic Vortex Modulation of Particle Rings and Particle Clusters via Asymmetric Propagation of Surface Acoustic Waves.

As a basis for biometric and chemical analysis, issues of how to dilute or concentrate substances such as particles or cells to specific concentrations have long been of interest to researchers. In this study, travelling surface acoustic wave (TSAW)-based devices with three frequencies (99.1, 48.8, 20.4 MHz) have been used to capture the suspended Polystyrene (PS) microspheres of various sizes (5, 20, 40 µm) in sessile droplets, which are controlled by acoustic field-induced fluid vortex (acoustic vortex) and aggregate into clusters or rings with particles. These phenomena can be explained by the interaction of three forces, which are drag force caused by ASF, ARF caused by Leaky-SAW and varying centrifugal force. Eventually, a novel approach of free transition between the particle ring and cluster was approached via modulating the acoustic amplitude of TSAW. By this method, multilayer particles agglomerate with 20 µm wrapped around 40 µm and 20 µm wrapped around 5 µm can be obtained, which provides the possibility to dilute or concentrate the particles to a specific concentration.

Effects of polystyrene nanoplastics (PSNPs) on the physiology and molecular metabolism of corn (Zea mays L.) seedlings.

The effects of polystyrene nanoplastics (PSNPs) on the physiological and molecular metabolism of corn seedlings were examined by treating corn (Zea mays L.) seedlings with 100, 300, and 500 nm diameter PSNPs and examining plant photosynthetic characteristics, antioxidant enzyme systems, and molecular metabolism. After 15 days of exposure to PSNPs with different particle sizes (50 mg·L-1), the photosynthetic characteristics of the plant remained stable, and the maximum photochemical quantum yield (Fv/Fm) and non-photochemical quenching coefficient (NPQ) had no significant effects. The root microstructure was damaged and the antioxidant enzyme system was activated, and the content of malondialdehyde (MDA) was significantly increased by 2.25-4.50-fold. In addition, 100 nm and 300 nm PSNPs exposure caused root superoxide dismutase (SOD) activity to increase 1.28-fold and 1.53-fold, and glutathione-peroxidase (GSH-PX) activity increased 1.30-fold and 1.58-fold. Non-targeted metabolomics analysis identified a total of 304 metabolites. Exposure to 100, 300, and 500 nm PSNPs led to the production of 85 (upregulated: 85, downregulated: 0), 73 (upregulated: 73, downregulated: 0), and 86 (upregulated: 84, downregulated: 2) differentially expressed metabolites, respectively, in the plant roots. Co-expressed differential metabolites accounted for 38.2% of the metabolites and indicated a metabolic imbalance primarily in organic acids and derivatives in the root system. The most significant enrichment pathways were those of alanine, aspartate, and glutamate metabolism. Overall, exposure to PSNPs of different particle sizes activated the root antioxidant enzyme system and interfered with plant basic metabolism. The alanine, aspartate, and glutamate metabolic pathways appear to be closely related to plant mechanisms for tolerance/detoxification of PSNPs.

Alterations of the rhizosphere soil microbial community composition and metabolite profiles of Zea mays by polyethylene-particles of different molecular weights.

Polyethylene film is the most widely used plastic film in agricultural production activities, and its depolymerization products are mainly polyethylene-particles (PE-particles) of different molecular weights. However, the impact of the molecular weights of the PE-particles on soil-crop microenvironment has not been elucidated. In this study, a potted microcosmic simulation system was used to evaluate the impact of low, medium and high molecular weight PE-particles on soil metabolism, microbial community structure, and crop growth. There were obvious differences in the shape and surface microstructure of PE-particles with different molecular weights. Soil sucrase and peroxidase had significant responses to PE-particles of different molecular weights. In the rhizosphere, the number of microorganisms and the microbial alpha diversity index increased with increasing PE-particles molecular weight. Rhizobacter, Nitrospira, and Sphingomonas were the dominant microorganisms induced by PE-particles to regulate the metabolism of elements. Carbohydrate and amino acid contents in rhizosphere soils were the key factors affecting the species abundance of Lysobacter, Polyclovorans, Rhizobacter, and Sphingomonas. In plants, PE-particles treatment reduced the plant biomass and photosynthetic rate and disrupted normal mineral nutrient metabolism. Different molecular weight PE-particles may therefore have adverse effects on the soil-plant system.

Transformation of polyvinyl chloride (PVC) into a versatile and efficient adsorbent of Cu(II) cations and Cr(VI) anions through hydrothermal treatment and sulfonation.

The reuse of waste polyvinyl chloride (PVC) has drawn much attention as it can reduce plastic waste and associated pollution, and provide valuable raw materials and products. In this study, sulfonated PVC-derived hydrochar (HS-PVC) was synthesized by two-stage hydrothermal treatment (HT) and sulfonation, and shown to be a versatile adsorbent. The removal of Cu(II) cations and Cr(VI) anions using HS-PVC reached 81.2 ± 1.6% and 60.3 ± 3.8%, respectively. The first stage of HT was crucial for the dichlorination of PVC and the formation of an aromatic structure. This stage guaranteed the introduction of -SO3H onto PVC-derived hydrochar through subsequent sulfonation. HT intensities (i.e., temperature and time) and sulfonation intensity strongly determined the adsorption capacity of HS-PVC. Competitive adsorption between Cu(II) and Cr(VI) onto HS-PVC was demonstrated by binary and preloading adsorption. The proposed Cu(II) cations adsorption mechanism was electrostatic adsorption, while Cr(VI) were possibly complexed by the phenolic -OH and reduced to Cr(III) cations by CC groups in HS-PVC. In addition, HS-PVC derived from PVC waste pipes performed better than PVC powder for Cu(II) and Cr(VI) removal (＞90%). This study provides an efficient method for recycling waste PVC and production of efficient adsorbents.

Autologous bionic tissue for inguinal hernia repair.

The prosthetic mesh, which is widely used in tension-free hernioplasty, often result in avascular stiff fibrotic scar or mesh shrinkage, causing chronic pain and infection. Here, we developed an autologous bionic tissue (ABT), which was composed of autologous bone marrow-derived mesenchymal stem cells (MSCs), poly (lactic-co-glycolic acid) (PLGA) porous scaffolds, and extracellular matrix (ECM) produced by MSCs for inguinal hernioplasty. In ABT, MSCs produced a variety of ECM composites, such as structural proteins (insoluble collagen, elastin) that provided mechanical properties, macromolecules (hyaluronic acid, glycosaminoglycan) as water and cytokines reservoir, and cell-engaging proteins (fibronectin, laminin). The above ECM composites reached the highest level in 21 days. ECM degradation related cytokines (MMP-9 and its inhibitor TIMP-1) reached the highest level on the 14th day. ECM increased the mechanical properties, elasticity, and flexibility of PLGA. Compared with the PLGA, ABT greatly inhibited inflammatory factors and promoted anti-inflammatory factors (p < 0.05), and gradually reduced the M1/M2 ratio in vivo (p < 0.05). After implantation, the thickness of tissue regeneration (p < 0.05), the number of capillaries or mature vessels (p < 0.05), the mechanical properties of ABT (p < 0.05) were greater than PLGA. MSCs and ECM could reduce the inflammation caused by PLGA, and prevent PLGA from earlier degradation and facilitate host cellular infiltration, thus ABT could greatly promote tissue regeneration in hernia repairs.

Vesselplasty using the Mesh-Hold™ bone-filling container for the treatment of pathological vertebral fractures due to osteolytic metastases: A retrospective study.

PURPOSE: To evaluate the clinical benefits and complications of vesselplasty using the Mesh-Hold™ bone-filling container in the treatment of vertebral osteolytic fractures. METHODS: This was a retrospective study of patients with vertebral osteolytic pathological fractures treated by vesselplasty at Sichuan Cancer Hospital between 09/2014 and 01/2018. VAS1 (Visual analog scale) scores and ODI2 (Oswestry disability index) were recorded routinely 1 day preoperative, at 1 day, 1 month, 3 months, 6 months, and 1 year postoperation, and at the last follow-up. V13 (The of bone cement injection volume) and V24 (vertebral body osteolytic volume) were evaluated, and the R5 (ratio) of bone cement filling was obtained according to the V1/V2. RESULTS: Sixty-three patients were included (105 segments with osteolytic fractures). The amount of bone cement for each vertebra was 2.4-5.2 ml (3.1 ± 0.7 ml). The ratio (R) of bone cement filling was not related to pain relief or functional recovery (all P > 0.05).The VAS scores and ODI at different time points after surgery were decreased compared with before surgery (all P < 0.05). The bone cement leakage rate was 16.2 % (17/105). The follow-up was 4-30 months (mean of 13 ± 6 months). Thirty patients had died by the last follow-up, all from their cancer. CONCLUSIONS: The Mesh-Hold™ bone-filling container in the treatment of vertebral fractures induced by osteolytic metastases could reduce pain, improve function, and reduce the bone cement leakage rate in the process of vesselplasty.

Determination of benzalkonium chloride partition in micelle solutions using ultrafiltration method.

The objectives of this study were to determine the concentrations of free benzalkonium chloride (BAC) and apparent partitions coefficients (Km) in micelle solutions and to explore its application in formulation development. Ultrafiltration (UF) was carried out using 10K Nanosep devices and centrifugation at 5,000 rpm for 5 min. The separation of free BAC from micellar solutions was also conducted using ultracentrifugation (UC) method for the comparison with UF method. Capillary electrophoresis method was used for the identification of micelles. Results showed that a UF method was applicable for quantitatively evaluating BAC-micelle interaction in micellar solutions. Unlike UF, UC could not completely separate free BAC from the micelles. The free BAC concentrations in the micelle solutions decreased with increasing surfactant concentrations. Among polysorbate 80, cremophor EL, and tyloxapol, BAC had the highest Km in polysorbate 80 solutions. The Km was significantly lower in non-buffered aqueous solutions than that in citric buffers. Moreover, increasing surfactant concentrations led to reducing antimicrobial activity. The UF is a rapid and accurate method that minimally alters the micellar equilibrium for the determination of free BAC and Km in micellar solutions. In conclusion, free BAC concentration, which is a function of surfactant type, surfactant concentration, and ion strength of solution, is likely associated with the antimicrobial activity.

[Distribution and Sources of n-alkanes in Surface Seawater of Jiaozhou Bay].

Hydrocarbons emitted by human activities probably constitute the largest class of contaminants that are present in coastal areas, because of widespread use of fossil fuels for power generation and logistics, and accidental spillages. The chemical composition of hydrocarbon mixtures found in the marine environment allowed the identification of relative contributions of different natural and anthropogenic sources. Identification of these hydrocarbons, especially n-alkanes, could act as tracers for the possible sources. To evaluate n-alkanes concentrations with emphasis on source analysis, surface water without visible oil was collected from the cruise in April 2016. Determination and quantification were performed by solvent extraction and gas chromatography-mass spectrometry. Various molecular diagnostic parameters were used to assess the contribution of different sources and origin of n-alkanes in surface seawater of Jiaozhou Bay. Concentrations of total dissolved n-alkanes(C11-C37) were between 1.756-39.09 µg·L-1 with a high carbon number predominance profile without odd-even carbon number preference. The n-alkane concentrations varied spatially depending on the distance away from main input sources and the ability of water exchange. It was at a higher concentration in the northeast and west coastal areas, as well as the mouth of Jiaozhou Bay. And concentrations were relatively lower in the inner area and outside of Jiaozhou Bay. In the sea area with strong water exchange, concentrations of total n-alkanes were around 2.196 µg·L-1, which could be considered as the environmental background level of n-alkanes in Jiaozhou Bay. Those n-alkanes were dominated with C24, with a slightly odd carbon number preference in low carbon n-alkanes and an even carbon number preference in high carbon n-alkanes. The values of CPI for the whole range of n-alkanes series, low carbon n-alkanes, and high carbon n-alkanes were 0.949, 1.026, and 0.980, respectively. Diagnostic indices and curves indicated that the dominant inputs of those n-alkanes were from marine biogenic input such as algae and marine bacteria. The concentration profiles of n-alkanes in other areas were characterized by no odd-even predominance in the range of C21-C33 with peaks center at C24 which were indicative of anthropic contributions as emission sources. N-alkanes dominating with anthropic sources comprised a high proportion(83.7%) of total n-alkanes. Activities of harbors and ships were the main contributors of Jiaozhou Bay n-alkanes. Physical processes, such as evaporation and dilution, were the principal weathering mechanisms. Because of its sufficient environmental capacity, Jiaozhou Bay was still moderately contaminated with petroleum.

Role of extracellular exopolymers on biological phosphorus removal.

Three sequencing batch reactors supplied with different carbon sources were investigated. The system supplied with glucose gained the best enhanced biological phosphorus removal although all of the three reactors were seeded from the same sludge. With the measurement of poly-beta-hydroxyalkanoate (PHA) concentration, phosphorus content in sludge and extracellular exopolymers (EPS) with scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS), it was found that the biosorption effect of EPS played an important role in phosphorus removal and that the amount of PHA at the end of anaerobic phase was not the only key factor to determine the following phosphorus removal efficiency.

Optic nerve regeneration in polyglycolic acid-chitosan conduits coated with recombinant L1-Fc.

Autografts have been extensively studied to facilitate optic nerve (ON) regeneration in animal experiments, but the clinical application of this approach to aid autoregeneration has not yet been attempted. This study aims to explore the guided regeneration by an artificial polyglycolic acid-chitosan conduit coated with recombinant L1-Fc. Consistent with previous studies; in vitro assay showed that both chitosan, a natural biomaterial, and the neural cell adhesion molecule L1-Fc enhanced neurite outgrowth. Rat optic nerve transection was used as an in vivo model. The implanted PGA-chitosan conduit was progressively degraded and absorbed, accompanied by significant axonal regeneration as revealed by immunohistochemistry, anterograde and retrograde tracing. The polyglycolic acid-chitosan conduit coated with L1-Fc showed more effective to promote axonal regeneration and remyelination. Taken together, our observations demonstrated that the L1-Fc coated PGA-chitosan conduits provided a compatible and supportive canal to guild the injured nerve regeneration and remyelination.

[Impacts of filamentous bulking on treatment effect and fouling characteristics of nonwoven bioreactor].

Sludge flocs morphology and effluent qualities of nonwoven bioreactor during filamentous bulking and normal sludge status were compared. Flux variations, analysis of filtration resistances and extracellular polymer substances (EPS) contents during filamentous bulking and normal sludge status were studied. The results showed that the average particle size of bulking sludge flocs and normal sludge flocs was 448.6 microm and 234.8 microm, respectively. During the bulking sludge status, the average COD and NH4(+) -N removal rate and effluent turbidity were 90.1%, 93.1% and 1.33 NTU, respectively, compared with 91.4% , 97.0% and 0.99 NTU during the normal sludge status. Filamentous bulking had little impact on COD removal, while it inhibited NH4(+) -N removal to a certain extent and had slight impact on effluent turbidity. Average membrane flux decay rates during the bulking sludge status and the normal sludge status were 3.29 L x (m2 x h2)(-1) and 4.87 L x (m2 x h2)(-1), respectively, and the fouling during bulking sludge status was slighter. Reversible fouling was the main fouling when sludge was bulking while irreversible fouling was the main fouling when the sludge was in normal status. The prior occurrence of reversible fouling could reduce irreversible fouling therefore slow down the flux decline. Soluble microbial products (SMP) contents in normal sludge mixed liquid and bulking sludge mixed liquid were 21.369 mg x L(-1) and 10.182 mg x L(-1), respectively, protein/polysaccharide (P/C) was 0.370 and 0.497, respectively, SMP gross was related to fouling resistance and P/C was associated with reversible fouling proportion. The relation between loosely bound EPS in mixed liquid sludge and membrane fouling was similar to SMP. Sludge with more EPS could accumulate on membrane more easily, and the EPS that accumulated on membrane was mainly protein. EPS gross in mixed liquid sludge, EPS in membrane surface sludge and their P/C all had positive correlations to reversible fouling.

Algal-based immobilization process to treat the effluent from a secondary wastewater treatment plant (WWTP).

Algal-based immobilization process was applied to treat the effluent from a secondary wastewater treatment plant. Batch test proved that algae could attach onto fiber-bundle carrier in 7 days, and then the algal-based immobilization reactor could reduce TN (total nitrogen) and TP (total phosphorus) significantly within 48 h. Based on the above investigations, the hydraulic retention time (HRT) of the algal-based immobilization reactor in continuous operation mode was determined to be 2 days. During the 91 days of experiment on the treating secondary effluent of Guang-Rao wastewater treatment plant, it was found that the fiber-bundle carrier could collect the heterobacteria and nitrifying bacteria gradually, and thus improved the COD removal efficiency and nitrification performance step by step. Results of the continuous operation indicated that the final effluent could meet the Chinese National First A-level Sewage Discharge Standard when the algal-based immobilization reactor reached steady state.

Factors affecting simultaneous nitrification and de-nitrification (SND) and its kinetics model in membrane bioreactor.

Experiments have been carried out to investigate the effect of biological factors such as dissolved oxygen (DO), food/microorganism (F/M) ratio, carbon/nitrogen (C/N) ratio and pH on performance of SND in membrane bioreactor (MBR). It was found that a low DO was advantageous to SND on condition that nitrification was not inhibited, while F/M ratio and C/N ratio have reverse effects on SND, and pH should also be controlled in a suitable range. Based on the conventional activated sludge model, a deduction was conducted to illustrate that SND could take place from the theoretical aspect, and it was proved that high organics was effective in improving SND. In addition, a kinetic model for SND was constituted on the basis of batch test result, and the simulation nitrate saturation coefficient K(NO)(3) was much higher than that in a single-sludge wastewater treatment system.

Multiplanar and combined distraction osteogenesis for three-dimensional and functional reconstruction of unilateral large maxillary defects.

We have developed a new way of three-dimensional and functional reconstruction of unilateral large maxillary defects by multiplanar and combined distraction osteogenesis of the zygoma, maxillary alveolar process, and hard palate. In the first procedure we started the internal curvilinear distraction osteogenesis of the left zygoma in one patient who had had a left maxillectomy to rebuild midfacial bony support. In the second procedure, the internal curvilinear distraction osteogenesis of the maxillary anterior alveolar process and straight distraction osteogenesis of the right hard palate were used to restore the posterior alveolar process and left palate. In the third procedure, the distracted zygoma and alveolar process were connected by a small local bone graft. The important lost maxillary bony architecture was re-established three-dimensionally and resulted in a natural facial appearance, normal speech and swallowing, and good foundation for chewing. This may be the first example of three-dimensional and functional reconstruction of unilateral large maxillary defects that did not require bone grafts from other anatomical areas.

Evaluation of a new semiburied curvilinear distraction device in dogs.

We developed a semiburied, curvilinear distraction device for use in osteogenesis in the reconstruction of maxillofacial defects. The device was tested in two dogs, which had segmental defects made in the maxilla and zygoma. The residual zygoma was distracted with the device. The bony transport discs were distracted about 12mm around an arc, and the new bone formed well in the distracted gap. The semiburied curvilinear distraction device has proved to be reliable for internal curvilinear distraction. Its clinical applicability needs to be studied further.

[Application of multislice helical computed tomography in maxillofacial distraction osteogenesis].

OBJECTIVE: To develop the method and investigate the value of the application of multislice helical computed tomography (CT) in the maxillofacial distraction osteogenesis. METHODS: Twelve cases of maxillofacial distraction osteogenesis (3 in zygoma, 2 in maxilla, and 7 in mandible) were scanned by the multislice helical CT, then the reconstruction of three dimensional and fault image and the relative measurement were carried out to study the effect of distraction and osteogenesis. RESULTS: The three dimensional image provided clear and high resolution stereoscopic view that the effect of distraction osteogenesis could be evaluated easily and exactly. The fault image could be set up in private computer by Mimics and the measurements, such as distance, thickness and density, could be performed as expected. The effect of 12 cases was satisfied, and the average distracted distance was 16.73 mm. CONCLUSION: Basing on multislice helical CT scanning, the high resolution image reconstruction and relative measurement data could be obtained which could meet the need of clear and direct observation. Its application in the maxillofacial distraction osteogenesis is expecting and promising.

[Effects of bagasse polysaccharide on the immune functions of immunosuppressed mice].

OBJECTIVE: To observe the effects of bagasse polysaccharide on the immune functions of immunosuppressed mice. METHODS: Immunosuppressed mouse models were established by intraperitoneal injections with cyclophosphamide followed by daily intragastric administration of bagasse polysaccharide. After the treatments, the mice were examined for immune organ weight index, phagocytotic function of the macrophages, delayed type hypersensitivity, serum IgM level following exposure to chicken red blood cells, formation of hemolytic plaques, T cell percentage and lymphocyte transformation. RESULTS: Treatment of the immunosuppressed mice with bagasse polysaccharide at the daily dose of 200 and 400 mg/kg significantly increased the weight of the immune organs, phagocytotic function of the macrophages, delayed type hypersensitivity, serum IgM level against chicken red blood cells, formation of hemolytic plaques, T cell percentage and lymphocyte transformation. CONCLUSION: Bagasse polysaccharide can enhance the immune functions of immunosuppressed mice.

[Segmental reconstruction of maxillary defects by arced distraction osteogenesis of zygoma].

OBJECTIVE: To study the possibility of segmental maxillary regeneration by arced distraction osteogenesis of zygoma. METHODS: The distraction of zygoma with the internal arced devices was performed in 2 dogs to simulate the reconstruction of maxillary defect. The zygoma was distracted about 12 mm, and the process of new bone formation was studied by histology and scanning electron microscopy. RESULTS: The transport disk was distracted about 12 mm around the arc. After 8 weeks of consolidation, the density of new bone was close to that of normal bone. CONCLUSIONS: The segmental maxillary regeneration by arced distraction osteogenesis of zygoma is possible.