An all-organic conditioning method to achieve deep dewatering of waste activated sludge and the underlying mechanism.

Among the common treatment/disposal routes of excessive activated sludge from municipal wastewater treatment plant, dewatering process functions as an essential pre-/post-treatment for volume minimization and transportation facilitation. Since inorganic coagulants have long been criticized for their high dosage and solid residue in sludge cake, there is an urgent need for investigations regarding the potential of applying organic chemicals as the conditioner. In this study, combined use of poly dimethyldiallylammonium chloride (PDMD) and tannic acid (TA) were investigated as an all-organic co-conditioning method for sewage sludge pre-treatment. Results showed that this all-organic conditioning strategy can effectively improve the dewaterability of sewage sludge. The capillary suction time reduced from 128.8 s to 23.1 s, and the filtration resistance reduced from 1.24 × 1012 cm/g to 7.38 × 1010 cm/g. The moisture content of dewatered sludge cake decreased to as low as 55.83%, showing the highest dewatering efficiency reported so far. In addition, the combination of PDMD and TA maximized the treating efficiency with very limited consumption of conditioners (added up to 4% of total solid). Based on the physic-chemical and rheological property investigation, it was proposed that the intermediate molecular weight polymer-based flocculation process and the TA agent-based protein precipitation process, could remarkably strengthen the compactness and structure robustness of sludge. In all, this PDMD-TA-based conditioning method suggested practical significance in consideration of its cost-effectiveness and disposal convenience of sludge cake.

Jaw-muscle force and excursion scale with negative allometry in platyrrhine primates.

OBJECTIVES: Platyrrhines span two orders of magnitude in body size and are characterized by diverse feeding behaviors and diets. While size plays an important role in primate feeding behavior and masticatory apparatus morphology, we know little about size-correlated changes in the force-generating (physiologic cross-sectional area; PCSA) and excursion/stretch (fiber length; Lf ) capabilities of the jaw-closing muscles in platyrrhines. METHODS: We examined scaling relationships of the superficial masseter and temporalis muscles in 21 platyrrhine species. Previous work suggests that larger platyrrhines are at a mechanical disadvantage for generating bite forces compared with smaller platyrrhines. We hypothesize that scaling of jaw-muscle fiber architecture counters this size-correlated decrease in mechanical advantage. Thus, we predicted that jaw-muscle PCSAs and muscle weights scale with positive allometry while Lf s scale with negative allometry, relative to load-arm estimates for incisor/molar biting and chewing. RESULTS: Jaw-muscle PCSAs and Lf s appear to scale with negative allometry relative to load-arm estimates and body size. Negative allometry of jaw-muscle weights partially accounts for the size-correlated decreases in PCSA and Lf . Estimates of bite force also scale with negative allometry. CONCLUSION: Large-bodied platyrrhines (e.g., Alouatta) are at a relative disadvantage for generating jaw-muscle and bite force as well as jaw-muscle stretch, compared with smaller species (e.g., Callithrix). The net effect is that larger platyrrhines likely produce relatively smaller maximal bite forces compared with smaller taxa. Relative to small- and intermediate-sized platyrrhines, large-bodied platyrrhines feed on some of the least mechanically challenging foods, consistent with the size-correlated decrease in relative muscle and bite forces across the clade. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc. Am J Phys Anthropol 158:242-256, 2015. © 2015 Wiley Periodicals, Inc.

Porosity-permeability tensor relationship of closely and randomly packed fibrous biomaterials and biological tissues: Application to the brain white matter.

The constitutive model for the porosity-permeability relationship is a powerful tool to estimate and design the transport properties of porous materials, which has attracted significant attention for the advancement of novel materials. However, in comparison with other materials, biomaterials, especially natural and artificial tissues, have more complex microstructures e.g. high anisotropy, high randomness of cell/fibre dimensions/position and very low porosity. Consequently, a reliable microstructure-permeability relationship of fibrous biomaterials has proven elusive. To fill this gap, we start a mathematical derivation from the fundamental brain white matter (WM) formed by nerve fibres. This is augmented by a numerical characterisation and experimental validations to obtain an anisotropic permeability tensor of the brain WM as a function of the tissue porosity. A versatile microstructure generation software (MicroFiM) for fibrous biomaterial with complex microstructure and low porosity was built accordingly and made freely accessible here. Moreover, we propose an anisotropic poro-hyperelastic model enhanced by the newly defined porosity-permeability tensor relationship which precisely captures the tissues macro-scale permeability changes due to the microstructural deformation in an infusion scenario. The constitutive model, theories and protocols established in this study will both provide improved design strategies to tailor the transport properties of fibrous biomaterials and enable the non-invasive characterisation of the transport properties of biological tissues. This will lead to the provision of better patient-specific medical treatments, such as drug delivery. STATEMENT OF SIGNIFICANCE: Due to the microstructural complexity, a reliable microstructure-permeability relationship of fibrous biomaterials has proven elusive, which hinders our way of tuning the fluid transport property of the biomaterials by directly programming their microstructure. The same problem hinders non-invasive characterisations of fluid transport properties in biological tissues, which can significantly improve the efficiency of treatments e.g. drug delivery, directly from the tissues accessible microstructural information, e.g. porosity. Here, we developed a validated mathematical formulation to link the random microstructure to a fibrous material's macroscale permeability tensor. This will advance our capability to design complex biomaterials and make it possible to non-invasively characterise the permeability of living tissues for precise treatment planning. The newly established theory and protocol can be easily adapted to various types of fibrous biomaterials.

Waggle needling Yanglingquan (GB34) enhances cerebral blood flow and ameliorates condition of spastic paresis in rats with middle cerebral artery occlusion induced by surgical nylon suture.

OBJECTIVE: To evaluate the therapeutic efficacy and the influence on cerebral blood supply of waggle needling Yanglingquan (GB34) on spastic paresis (SP) rats after middle cerebral artery occlusion (MCAO) induced and investigate its mechanism of relieving neurobehavior deficiency. METHODS: SP rat model was produced by permanent MCAO. Rats were divided into five groups: blank control group (Control), sham operation group (Sham), model group (Model), waggle needling group (WN) and perpendicular needling group (PN). SP rats were treated with acupuncture from day 3 after MCAO, once a day for 6 d. The modified neurological severity score (mNSS) and modified Ashworth scale (MAS) were conducted on days 0, 1, 3, 5, 7 and 9. Cerebral blood flow (CBF) in ischemic cortex was measured by laser speckle imaging 5 min pre ischemia, 5 min post ischemia, and after intervention on day 9. All rats were sacrificed at day 9 and the protein and mRNA expressions of γ2 subunit of the γ-aminobutyric acid receptor A (GABAAγ2) and K+-Cl?cotransporter 2 (KCC2) in the ischemic cortex and lumber enlargement was measured by Western blotting and real-time quantitative polymerase chain reaction. RESULTS: Both Control and Sham groups showed no changes in mNSS and MAS scores and in the regional CBF. Compared with Model group, both WN and PN treatments significantly ameliorated neurological deficit ( 0.01), decreased muscle tone ( 0.05), and enhanced CBF ( 0.001) in SP rats; moreover, WN showed superior effects than PN ( 0.001). In line with the improvement in neurobehavior, acupuncture interventions up-regulated the expressions of GABAAγ2 and KCC2 in the ischemic cortex as well as lumber enlargement ( 0.01) in SP rats, and those changes were more obvious in WN ( 0.05). CONCLUSIONS: Acupuncture at Yanglingquan (GB34) enhanced cerebral blood flow and ameliorated SP in permanent MCAO rats, while waggle needling was superior to regular perpendicular needling. Waggle needling Yanglingquan (GB34) would be a potential complementary therapy for SP.

A review on recovery of extracellular biopolymers from flocculent and granular activated sludges: Cognition, key influencing factors, applications, and challenges.

A reasonable recovery of excess sludge may shift the waste into wealth. Recently an increasing attention has been paid to the recycling of extracellular biopolymers from conventional and advanced biological wastewater treatment systems such as flocculent activated sludge (AS), bacterial aerobic granular sludge (AGS), and algal-bacterial AGS processes. This review provides the first overview of current research developments and future directions in the recovery and utilization of high value-added biopolymers from the three types of sludge. It details the discussion on the recent evolvement of cognition or updated knowledge on functional extracellular biopolymers, as well as a comprehensive summary of the operating conditions and wastewater parameters influencing the yield, quality, and functionality of alginate-like exopolymer (ALE). In addition, recent attempts for potential practical applications of extracellular biopolymers are discussed, suggesting research priorities for overcoming identification challenges and future prospects.

Supramolecular medical antibacterial tissue adhesive prepared based on natural small molecules.

In the field of biomedicine, tissue bio-adhesives require the use of polymer materials with integrated functions to meet changing practical applications. However, the currently available tissue glues cannot balance mechanical properties and biocompatibility. Inspired by the conversion of lipoic acid from small molecular biological sources into high-performance supramolecular polymeric materials, thioctic acid (TA) was modified and polyethylene glycol diacrylate (PEGDA) was introduced. Successfully constructed a dry gel with antibacterial effect and promote infection for wound regeneration. The prepared modified lipoic acid is mixed with PEGDA, melted under mild heating and self-assembled, and then directly extruded on both sides of the wound. It quickly cures at 37 °C and firmly adheres to both sides of the wound. The material exhibits good processability and rapid self-healing ability due to the cross-linked structure of the internal disulfide bonds and thioether bonds. In addition, the characteristics of TA make the prepared xerogels have good tissue adhesion and good antibacterial properties. This work proposes an innovative material with mechanical strength and biocompatible tissue glue, which provides broad prospects for application in wound treatment.

Enhanced hydrolysis and acidification of cellulose at high loading for methane production via anaerobic digestion supplemented with high mobility nanobubble water.

In this study, CH4 production from anaerobic digestion (AD) of refractory cellulose was investigated at a high loading of 3.5 (VScellulose/VSinoculum) under nanobubble water (NBW) addition. A longer proton spin-spin relaxation time (2611-2906 ms) of NBW during 35 days' storage reflected its high mobility and diffusion of water molecules. Higher volatile fatty acids were yielded at the hydrolysis-acidification stage under NBW addition. Methanogenesis tests showed that Air-NBW and CO2-NBW supplementation accelerated the utilization of crystalline cellulose, achieving methane yields of 264 and 246 mL CH4/g-VSreduced, increasing by 18% and 10% compared to deionized water addition (the control), respectively. In addition, under NBW addition the cellulose crystallinity reduction was enhanced by 14-20% with microbial community being enriched with hydrolytic and methanogenic bacteria. Results from this work suggest that NBW environment with no chemical addition and relatively low energy consumption is advantageous for enhanced AD process of cellulosic biomass.

Silicone-covered biodegradable magnesium stent for treating benign esophageal stricture in a rabbit model.

BACKGROUND: Stent insertion can effective alleviate the symptoms of benign esophageal strictures (BES). Magnesium alloy stents are a good candidate because of biological safety, but show a poor corrosion resistance and a quick loss of mechanical support in vivo. AIM: To test the therapeutic and adverse effects of a silicone-covered magnesium alloy biodegradable esophageal stent. METHODS: Fifteen rabbits underwent silicone-covered biodegradable magnesium stent insertion into the benign esophageal stricture under fluoroscopic guidance (stent group). The wall reconstruction and tissue reaction of stenotic esophagus in the stent group were compared with those of six esophageal stricture models (control group). Esophagography was performed at 1, 2, and 3 weeks. Four, six, and five rabbits in the stent group and two rabbits in the control groups were euthanized, respectively, at each time point for histological examination. RESULTS: All stent insertions were well tolerated. The esophageal diameters at immediately, 1, 2 and 3 wk were 9.8 ± 0.3 mm, 9.7 ± 0.7 mm, 9.4 ± 0.8 mm, and 9.2 ± 0.5 mm, respectively (vs 4.9 ± 0.3 mm before stent insertion; P < 0.05). Magnesium stents migrated in eight rabbits [one at 1 wk (1/15), three at 2 wk (3/11), and four at 3 wk (4/5)]. Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was found significantly thinner in the stent group than in the control group (P < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ compared to rabbits with esophageal stricture and normal rabbits (P > 0.05). CONCLUSION: Esophageal silicone-covered biodegradable magnesium stent insertion is feasible for BES without causing severe injury or tissue reaction. Our study suggests that insertion of silicone-covered magnesium esophageal stent is a promising approach for treating BES.