The impact of dairy consumption on salivary inoculum.

Quantitative levels of harmful oral microbes present following complex surgical excisions of head and neck cancer are important since wounds are often contaminated through direct connection to the oral cavity and its flora. This possibility is especially important in irradiated patients who have decreased protective salivary function. In addition, high oral microbial levels increase and intensify oral mucositis leading to significant morbidity in patients treated with radiation therapy. One previously untested surgical teaching to decrease the bacterial inoculum present in the oral cavity is to counsel patients against consuming otherwise nutritious dairy products, as they are thought to coat the oral cavity with rate-limiting nutrients vital for bacterial growth. This risk may extend to individuals with chronic laryngeal penetration or aspiration, since salivary bacterial load might represent a lethal threat in the presence of marginal pulmonary reserve. A crossover study using six healthy adult volunteers and six patients who had previously undergone radiation therapy to an oropharyngeal primary site was performed. Saliva samples were quantitatively cultured in both groups with and without the consumption of dairy products at 1-h and 5-h intervals. Analysis of quantitative cultures demonstrated that the consumption of dairy products had no influence on bacterial levels present in previously radiated subjects and nonirradiated controls. Additionally, the consumption of dairy did not affect the composition of microbes present. Due to the lack of changes in both quantity and composition of oral bacteria seen in this study, patients would not benefit from the avoidance of dairy products.

A reactive compatibilization with the compound containing four epoxy groups for polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch ternary bio-composites.

How to effectively improve the poor interfacial adhesion between polylactic acid/poly(butylene adipate-co-terephthalate) (PLA/PBAT) matrix and thermoplastic starch (TPS) is still a challenge. Therefore, this work aims to introduce a convenient method to enhance the performance of PLA/PBAT/TPS blend by melt reactive extrusion. Here, using 4,4'-methylene-bis(N,N-diglycidyl-aniline) (MBDG) containing four epoxy groups as a reactive compatibilizer, and respectively using 1-methylimidazole (MI) or triethylenediamine (TD) as a catalyzer, serial PLA/PBAT/TPS ternary bio-composites are successfully prepared via melt reactive extrusion. The results showed that, under the catalysis of organic base, especially MI, the epoxy groups of MBDG can effectively react with hydroxyl and carboxyl groups of PLA/PBAT and hydroxyl groups in TPS to form chain-expanded and cross-linked structures. The tensile strength of the composites is increased by 20.0 % from 21.1 MPa, and the elongation at break is increased by 182.4 % from 17.6 % owing to the chain extension and the forming of cross-linked structures. The molecular weight, thermal stability, crystallinity, and surface hydrophobicity of the materials are gradually improved with the increase of MBDG content. The melt fluidity of the composites is also improved due to the enhancement of compatibility. The obtained PLA/PBAT/TPS materials have the potential to be green plastic products with good properties.

Effect of cone angles of a hydrocyclone for the separation of waste plastics with low value of density difference.

The cone angle of a hydrocyclone is believed to be an important parameter to affect the separation performance. For the recycling of waste plastics, this paper focused on the study of the influence of cone angles on the separation of light dispersed plastics (PET) and heavy dispersed plastics (PVC) by experiments and numerical simulations. The cone angle was changed from 3° to 28° either at given length of the cylindrical section or at fixed total length of the hydrocyclone. The separation performance varied with cone angles at given length of the cylindrical section more greatly than that at fixed total length of the hydrocyclone. Results show that particles with different sizes in mixture exhibited discrepant separation behaviors at various cone angles. There was an optimum cone angle at which the Newton efficiency peaked as 90.2%, while the purity of PET could also reach the highest. The proportion of cylindrical section could be properly small for the enhancement of Newton efficiency.

Bioconversion of bamboo shoot shell to methane assisted by microwave irradiation and fungus metabolism.

Bamboo shoot shell (BSS), a major byproduct from bamboo shoot industries with a high amount of output annually, needs to be sustainably management due to its impact on environment and human health. Anaerobic digestion is an eco-friendly and sustainable option, but its efficiency is limited by recalcitrance of lignocellulose structure. A cascade pretreatment (CP) using microwave irradiation and fungus metabolism was developed in this work to reduce the recalcitrance of BSS and enhance its methane production. The results showed significant synergistic effects of microwave irradiation and fungus metabolism on anaerobic digestion of BBS. The methane yield by CP increased by 162.9% (reached to 223.4 mL/g VS) when compared to control group. This was higher than both the values of fungal pretreatment (101.0 mL/g VS, 18.9% increase), and microwave pretreatment (110.5 mL/g VS, 30.1% increase) alone. Further mechanisms of the synergistic effects were revealed. Microwave irradiation provided dissolved products and more accessible BBS for fungus action. In particular, the GC-MS analysis indicated the dissolved products induced fungal laccase activity effectively, and the highest activity in CP was 1.91-fold higher than that in fungal pretreatment alone. The fungus in cascade process further increased accessible surface area and reducing sugars (20.2-43.2%, which compared to fungal pretreatment alone), and reduced significantly the lignin content (42.2-49.1%) and crystallinity (4.5-8.1%) of BSS.

Effects of drought-stress on seed germination and growth physiology of quinclorac-resistant Echinochloa crusgalli.

Echinochloa crusgalli (L.) Beauv. (barnyard grass) is considered a noxious weed worldwide, and is the most pernicious weed decreasing rice yields in China. Recently, E. crusgalli has evolved quinclorac resistance, making it among the most serious herbicide resistant weeds in China. The present study explored differences in germination and growth between quinclorac-resistant and -susceptible E. crusgalli collected in Hunan Province. The order of the seven E. crusgalli biotypes assessed, from high to low quinclorac-resistance, was: quinclorac-resistant, Chunhua, Hanshou, Shimen, Hekou, Dingcheng, and quinclorac-susceptible. With an increased in the level of quinclorac-resistance, the germination rate, length of young shoots and roots, and fresh weight of E. crusgalli were all decreased compared with that in more susceptible biotypes. However, there were no significant differences between quinclorac-resistant and susceptible E. crusgalli biotypes without polyethylene glycol 6000 treatment. Drought had a more obvious effect on glutathione S-transferases (GST) activity, determined by spectrophotometric method, in quinclorac-resistant E. crusgalli. Higher resistance level biotypes showed greater activity, and when treated with polyethylene glycol 6000 for 3 days, all E. crusgalli biotypes showed the highest GST activity. This study demonstrated that as the level of quinclorac-resistance increased, the rate of seed germination decreased, while the growth of young buds, young roots, and fresh weight decreased. Increased quinclorac-resistance may be related to the increased metabolic activity of GST in E. crusgalli.

Effect of the medium's density on the hydrocyclonic separation of waste plastics with different densities.

Hydrocyclones can be applied to recycle waste plastics with different densities through separating plastics based on their differences in densities. In the process, the medium density is one of key parameters and the value of the medium's density is not just the average of the density of two kinds of plastics separated. Based on the force analysis and establishing the equation of motion of particles in the hydrocyclone, a formula to calculate the optimum separation medium density has been deduced. This value of the medium's density is a function of various parameters including the diameter, density, radial position and tangential velocity of particles, and viscosity of the medium. Tests on the separation performance of the hydrocyclone has been conducted with PET and PVC particles. The theoretical result appeared to be in good agreement with experimental results.

Development, physiochemical characterization and forming mechanism of Flammulina velutipes polysaccharide-based edible films.

Edible films of Flammulina velutipes polysaccharide were prepared and characterized in terms of rheological, optical, morphologic, mechanical and barrier properties to evaluate their potential application in food packaging. Results suggested that FVP film prepared by the solution of 1:150 (w/v) had the optimal mechanical property, smooth and uniform surface, and good barrier property to water (37.92±2.00gmm/m(2)hkPa) and oxygen (37.92±2.01meq/kg). The capacity of film-formation might be related to inter-molecular and intra-molecular hydrogen bonds of FVP and formation of ß-glycosidic bonds during the process of film-formation. These findings will contribute to a theoretical basis for the development of FVP film in food packaging.

Development of functional biointerfaces by surface modification of polydimethylsiloxane with bioactive chlorogenic acid.

The effect of physicochemical surface properties and chemical structure on the attachment and viability of bacteria and mammalian cells has been extensively studied for the development of biologically relevant applications. In this study, we report a new approach that uses chlorogenic acid (CA) to modify the surface wettability, anti-bacterial activity and cell adhesion properties of polydimethylsiloxane (PDMS). The chemical structure of the surface was obtained by X-ray photoelectron spectroscopy (XPS), the roughness was measured by atomic force microscopy (AFM), and the water contact angle was evaluated for PDMS substrates both before and after CA modification. Molecular modelling showed that the modification was predominately driven by van der Waals and electrostatic interactions. The exposed quinic-acid moiety improved the hydrophilicity of CA-modified PDMS substrates. The adhesion and viability of E. coli and HeLa cells were investigated using fluorescence and phase contrast microscopy. Few viable bacterial cells were found on CA-coated PDMS surfaces compared with unmodified PDMS surfaces. Moreover, HeLa cells exhibited enhanced adhesion and increased spreading on the modified PDMS surface. Thus, CA-coated PDMS surfaces reduced the ratio of viable bacterial cells and increased the adhesion of HeLa cells. These results contribute to the purposeful design of anti-bacterial surfaces for medical device use.

Aptamer-conjugated Mn3O4@SiO2 core-shell nanoprobes for targeted magnetic resonance imaging.

The objective of this study was to evaluate the targeted T1-magnetic resonance imaging (MRI), quantitative biodistribution and toxicity of aptamer (AS411) conjugated Mn3O4@SiO2 core-shell nanoprobes (NPs) in human cervical carcinoma tumor-bearing mice. The NPs were firstly prepared by encapsulating a hydrophobic Mn3O4 core within an amino functionalized silica shell. The fluorophore rhodamine (RB) was doped into the silica shell and the amphiphilic polymer poly(ethylene glycol) (PEG) was modified on the surface of the shell to improve its biocompatibility, then the aptamer AS411 was conjugated onto the end of the PEG chains as targeting ligands. The final NPs were abbreviated as Mn3O4@SiO2(RB)-PEG-Apt. By means of in vitro fluorescence confocal imaging and in vivo MRI, the NPs have been demonstrated to target cancer cells and prominent tumor aggregation effectively. The imaging results were further confirmed by a quantitative biodistribution study. In addition, histological, hematological and biochemistry analysis also proved the low toxicity of NPs in vivo. Our results showed the great potential of the Mn3O4@SiO2(RB)-PEG-Apt NPs could be used as a multifunctional nanoplatform for long-term targeted imaging and therapy of cancer.

[Photochemical tissue bonding technique for repairing limbal stem cell deficiency].

OBJECTIVE: To investigate the feasibility of photochemical tissue bonding (PTB) technique in repairing limbal stem cell (LSC) deficiency and the effect on cornea wound healing. METHODS: LSCs were isolated from limbus of New Zealand rabbits by tissue block culture method, and then the LSCs of 2nd passage were cultured on de-epithelialized human amniotic membrane (HAM) for 3 weeks to prepare the HAM/LSC grafts. The LSC deficiency models of the left eyes were established by 0.5 mol/L NaOH in 24 New Zealand female rabbits, aged 3-4 months and weighing 1.5-2.0 kg. HAM/LSC grafts were used to repair the cornea wounds by sutures (suture group, n = 12) or by PTB technique (PTB group, n = 12). The gross was observed including the corneal transparency, erythema, and new blood vessel formation after surgery. At 3 and 28 days, the inflammatory cytokine of interleukin 1beta (IL-1beta), IL-6, and tumor necrosis factor alpha (TNF-alpha) were assayed by ELISA method; and the amount of new blood vessels were quantified by immunohistochemistry staining at 28 days. RESULTS: All animals survived to the end of the experiment. At 3 days, there was no obvious difference in the corneal transparency between 2 groups; at 28 days, the corneal transparency of PTB group was higher than that of suture group, and new blood vessels decreased. HE staining showed that mass inflammatory cells infiltrated between graft and cornea basal layer at 3 days, and no new blood vessel formed. inflammatory cells infiltration significantly decreased at 28 days in PTB group; the amount of new blood vessels was (2.0 +/- 0.8)/HP in PTB group and was (6.3 +/- 1.3)/HP in suture group, showing significant difference (t = 7.966, P = 0.002). At 28 days, the concentrations of inflammatory cytokine of IL-1beta, IL-6, and TNF-alpha in suture group were significantly higher than those in PTB group (P < 0.05); however, no significant differences were observed between 2 groups at 3 days (P > 0.05). CONCLUSION: PTB technique can be used to fix HAM/LSC grafts, which can decrease inflammatory cell infiltration and new vessel formation, and improve the outcomes when compared with suture technique.

Regeneration of ischemic heart using hyaluronic acid-based injectable hydrogel.

An injectable hydrogel was applied to regenerate a myocardial infarction and functional recovery of the heart. A myocardial infarction was induced in rat by circumflex artery ligation. A hyaluronic acid-based hydrogel was injected into the epicardium of the infarcted area. Then, cardiac functions and regeneration of the myocardium in sham-operated (SHAM), myocardial infarction (MI), and gel-injected group (GEL) (n = 6) were evaluated 4 weeks after the injection. Measurements of the thickness of the wall showed that the thickness in the GEL group increased by up to 200% compared with that in the MI group (p < 0.001). The infarcted area of the left ventricular in the GEL group decreased by 53% compared with the MI group (p < 0.001). The number of arterioles and capillaries in the border zone of the GEL group increased by 152% and 148%, whereas the apoptotic index decreased by 42% (p < 0.05). Measurement of the heart functions, such as ejection fraction, arterial elastance (Ea), dP/dt max, and dP/dt min, indicated that the injection of a hydrogel significantly facilitated the functional recovery compared with the MI group. Because of its simplicity, easy applicability, and a great regenerating potential, this injectable hydrogel promises as a treatment for myocardial infarction.