- Chemopreventive effect of Toona sinensis leaf extract on 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch squamous cell carcinogenesis. [JOURNAL ARTICLE]
- Arch Oral Biol 2016 Jun 15.:130-142.
Toona sinensis leaf extract (TSL) has been shown to have anti-tumor effects on cancer cell lines. This study aimed to investigate the chemopreventive potential and the underlying mechanism of TSL during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis.One hundred hamsters were divided into control (n=30), carcinogenic (n=20), preventive (n=42), and therapeutic (n=8) groups. The animals in carcinogenic and preventive groups were administered reverse osmosis water (carcinogenic group) or TSL (1g/kg bw) (preventive group) by gavage daily for 4 weeks, and their bilateral pouches were painted with a 0.5% DMBA solution for 4, 9, and 12 weeks. The animals in the therapeutic group were treated with DMBA for 12 weeks prior to TSL administration for 4 weeks. Expression levels of survivin, X chromosome-linked inhibitor of apoptosis (XIAP), proliferating cell nuclear antigen (PCNA), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) proteins were analyzed by immunohistochemistry. Apoptotic activity was examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method, cytochrome C, and poly (ADP-ribose) polymerase (PARP).In the preventive group, the results showed significant decreases not only in the incidences of squamous cell carcinoma (SCC) (50%) and epithelial dysplasia (62.5%) but also in the tumor number, tumor volume, tumor burden, and the severity of dysplastic lesions. The down-regulation of survivin, XIAP, PCNA, iNOS, and COX-2 proteins and the increased apoptotic activity indicated anti-proliferative and apoptosis-inducing abilities of TSL on DMBA-induced HBP carcinogenesis.The results suggested that TSL might be a promising candidate for the prevention of oral cancer.
- BcMtg2 is required for multiple stress tolerance, vegetative development and virulence in Botrytis cinerea. [Journal Article]
- Sci Rep 2016.:28673.
In Saccharomyces cerevisiae, the Mtg2 gene encodes the Obg protein, which has an important function in assembling ribosomal subunits. However, little is known about the role of the Obg GTPase in filamentous fungi. In this study, we identified an Mtg2 ortholog, BcMtg2, in B. cinerea. The BcMtg2 deletion mutant showed a defect in spore production, conidial germination and sclerotial formation. Additionally, the mutant increased sensitivity to various environmental stresses. The BcMtg2 mutant exhibited dramatically decreased virulence on host plant tissues. BcMtg2 mutant showed increased sensitivity to osmotic and oxidative stresses, and to Congo red (cell wall stress agent). In the yeast complement assay, growth defects of yeast BY4741ΔMTG2 mutant were partly restored by genetic complementation of BcMtg2 under these environmental stresses. Additionally, compared with the parental strain and complement strain, the BcMtg2 deletion mutant displayed a minor glycerol response to osmosis stress. These defective phenotypes were recovered in the complement strain ΔBcMtg2C, which was created by adding the wild-type BcMtg2 gene to the ΔBcMtg2 mutant. The results of this study indicate that BcMtg2 has a necessary role in asexual development, environmental stress response and pathogenicity in B. cinerea.
- Basic concepts and practical equations on osmolality: Biochemical approach. [REVIEW, JOURNAL ARTICLE]
- Clin Biochem 2016 Jun 22.
The terms osmotic pressure, osmotic coefficient, osmole, osmolarity, osmolality, effective osmolality and delta osmolality are formally defined. Osmole is unit of the amount of substance, one mole of nonionized impermeant solute is one osmole. Assuming an ideal solution, osmotic pressure (π) in mmHg is 19.3 times the osmolarity. Osmolarity is defined as the number of milliosmoles of the solutes per liter of solution. Suitable equations are presented for the rapid calculation of the osmolarity of different solutions. The concentrations of electrolytes are expressed by mEq/L that is, equal to their osmolarity as mOsm/L. If the solute concentration (C) is expressed as mg/L, mg/dL and g%, osmolarity is calculated as: C.n' /MW, C.n' (10)/MW and C.n' (10(4))/MW respectively. Osmolality is milliosmoles of solutes per one kilogram (or liter) of water of solution (plasma) and is calculated by osmolarity divided to plasma water. The osmolal concentration is corrected to osmolal activity by using the osmotic coefficient, φ. The salts of sodium (choloride and bicarbonate) and nonelectrolyte glucose and urea are the major five osmoles of plasma. The simplest equation: Posm =2 [Na(+)]+glucose (mg/dL)/18+BUN (mg/dL)//2.8 is also the simplest and best formula to calculate plasma osmolality. The concentration of only effective osmoles evaluates effective osmolality or tonicity as: Eosm =2 [Na(+)]+glucose/18. The normal range of plasma tonicity is 275-295mOsm/kg of water. The difference between the measured and calculated osmolality is called osmolal gap. It is recommended to withdraw the formula of Dorwart-Chalmers from the textbooks and autoanalyzers and to use the simplest equation of Worthley et al. as the best equation for calculating serum osmolality. Furthermore the normal ranges of osmolal gap also must be corrected to 0±2mOsm/L.
- Chemisorption of Perfluorooctanoic Acid on Powdered Activated Carbon Initiated by Persulfate in Aqueous Solution. [JOURNAL ARTICLE]
- Environ Sci Technol 2016 Jun 23.
Perfluorooctanoic acid (PFOA) is a perfluorocarboxylic acid that is difficult to treat by most conventional methods. As a result, it is often removed from solution by adsorption on powdered activated carbon (PAC), followed by incineration of the spent carbon. To provide a new approach for treatment, PFOA was exposed to sulfate radicals (SO4(-•)) produced by thermolysis of persulfate (S2O8(2-)) in the presence of PAC. Under acidic conditions, thermal activation of persulfate resulted in transformation of PFOA to shorter-chain-length perfluorinated compounds, as previously reported. However, when thermolysis of persulfate occurred under circumneutral pH conditions in the presence of PAC, a new removal pathway for PFOA was observed. Under these conditions, the removal of PFOA was attributable to chemisorption, a process in which PAC catalyzed persulfate decomposition and reacted with the transformation products to produce covalently bound PFOA. At PAC concentrations between 200 and 1000 mg/L and an initial PFOA concentration of 0.5 μM, covalent bonding resulted in removal of 10-40% of the PFOA. Under these conditions, the process resulted in removal of more than half of a more hydrophilic perfluoroalkyl acid (i.e., perfluorobutanoic acid, PFBA), which was greater than the amount of PFBA removed by physical adsorption on PAC. Although the high reaction temperatures (i.e., 80 °C) and relatively high doses of PAC used in this study may be impractical for drinking water treatment, this process may be applied to the treatment of these recalcitrant compounds in industrial wastewater, reverse osmosis concentrate, and other waters that contain high concentrations of PFOA and other perfluorocarboxylic acids.
- Energy Consumption by Recirculation: A Missing Parameter When Evaluating Forward Osmosis. [JOURNAL ARTICLE]
- Environ Sci Technol 2016 Jun 23.
- Characterization of spherical domains at the polystyrene thin film-water interface. [Journal Article]
- Beilstein J Nanotechnol 2016.:581-90.
Spherical domains that readily form at the polystyrene (PS)-water interface were studied and characterized using atomic force microscopy (AFM). The study showed that these domains have similar characteristics to micro- and nanobubbles, such as a spherical shape, smaller contact angle, low line tension, and they exhibit phase contrast and the coalescence phenomenon. However, their insensitivity to lateral force, absence of long-range hydrophobic attraction, and the presence of possible contaminants and scratches on these domains suggested that these objects are most likely blisters formed by the stretched PS film. Furthermore, the analysis of the PS film before and after contact with water suggested that the film stretches and deforms after being exposed to water. The permeation of water at the PS-silicon interface, caused by osmosis or defects present on the film, can be a reasonable explanation for the nucleation of these spherical domains.
- Rapid novel test for the determination of biofouling potential on reverse osmosis membranes. [Journal Article]
- Water Sci Technol 2016; 73(12):2978-85.
A novel method was proposed to determine biofouling potential by direct analysis of a reverse osmosis (RO) membrane through fluorescence intensity analysis of biofilm formed on the membrane surface, thereby incorporating fouling tendencies of both feedwater and membrane. Evaluation of the biofouling potential on the RO membrane was done by accelerated biofilm formation through soaking of membranes in high biofouling potential waters obtained by adding microorganisms and glucose in test waters. The biofilm formed on the soaked membrane was quantified by fluorescence intensity microplate analysis. The soaking method's capability in detecting biofilm formation was confirmed when percentage coverage obtained through fluorescence microscopy and intensity values exhibited a linear correlation (R(2) = 0.96). Continuous cross-flow experiments confirmed the ability and reliability of the soaking method in giving biofouling potential on RO membranes when a good correlation (R(2) = 0.87) between intensity values of biofilms formed on the membrane during soaking and filtration conditions was obtained. Applicability of the test developed was shown when three commercially available polyamide (PA) RO membranes were assessed for biofouling potential. This new method can also be applied for the determination of biofouling potential in water with more than 3.6 mg L(-1) easily degradable organic carbon.
- Influence of concentration polarization on DNA translocation through a nanopore. [JOURNAL ARTICLE]
- Phys Rev E 2016 May; 93(5-1):052409.
Concentration polarization can be induced by the unique ion-perm selectivity of small nanopores, leading to a salt concentration gradient across nanopores. This concentration gradient can create diffusio-osmosis and induce an electric field, affecting ionic currents on DNA that translocates through a nanopore. Here this influence is theoretically investigated by solving the continuum Poisson-Nernst-Planck model for different salt concentrations, DNA surface charge densities, and pore properties. By implementing the perturbation method, we can explicitly compute the contribution of concentration polarization to the ionic current. The induced electric field by concentration polarization is opposite to the imposed electric field and decreases the migration current, and the induced diffusio-osmosis can decrease the convection current as well. Our studies suggest that the importance of the concentration polarization can be determined by the parameter λ/G where λ is the double-layer thickness and G is the gap size. When λ/G is larger than a critical value, the influence of concentration polarization becomes more prominent. This conclusion is supported by the studies on the dependence of the ionic current on salt concentration and pore properties, showing that the difference between two models with and without accounting for concentration polarization is larger for low salts and small pores, which correspond to larger λ/G.
- Single-step Assembly of Multifunctional Poly Tannic Acid-Graphene Oxide Coating to Reduce Biofouling of Forward Osmosis Membranes. [JOURNAL ARTICLE]
- ACS Appl Mater Interfaces 2016 Jun 13.
Graphene oxide (GO) nanosheets have anti-bacterial properties that have been exploited as a biocidal agent used on desalination membrane surfaces in recent research. Nonetheless, improved strategies for efficient and stable attachment of GO nanosheets onto the membrane surface are still required for this idea to be commercially viable. To address this challenge, we adopted a novel, single-step surface modification approach using tannic acid cross-linked with polyethylene imine as a versatile platform to immobilize GO nanosheets to the surface of polyamide (PA) thin film composite (TFC) forward osmosis (FO) membranes. An experimental design based on Taguchi's statistical method was applied to optimize the FO processing conditions in terms of water and reverse solute fluxes. Modified membranes were analyzed using water contact angle (WCA), adenosine triphosphate (ATP) bioluminescence, total organic carbon (TOC), Fourier transform infrared spectroscopy (FTIR), zeta potential, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). These results show that membranes were modified with a nanoscale (< 10 nm), smooth, hydrophilic coating that, compared to pristine membranes, improved filtration and significantly mitigated biofouling by 33% due to its extraordinary, synergistic antibacterial properties (99.9%).
- Membranes technology used in water treatment: Chemical, microbiological and ecotoxicological analysis. [JOURNAL ARTICLE]
- Sci Total Environ 2016 Jun 7.