When plasmonics meets membrane technology

In this review, we present the applications of thermoplasmonics in membrane processes. We discuss the influence of the heat capacity of the solvent, the amount of plasmonic nanoparticles in the membrane, the intensity of the light source and the transmembrane flow rate on the increase of permeability. Remarkably, thermoplasmonic effects do not involve any noticeable loss of membrane rejection. Herein, we consider application feasibilities, including application fields, requirements of feed, alternatives of light sources, promising thermoplasmonic nanoparticles and scaling up issues.

Nanofiltration based water reclamation from tannery effluent following coagulation pretreatment

Coagulation-nanofiltration based integrated treatment scheme was employed in the present study to maximize the removal of toxic Cr(VI) species from tannery effluents. The coagulation pretreatment step using aluminium sulphate hexadecahydrate (alum) was optimized by response surface methodology (RSM). A nanofiltration unit was integrated with this coagulation pre-treatment unit and the resulting flux decline and permeate quality were investigated. Herein, the coagulation was conducted under response surface-optimized operating conditions. The hybrid process demonstrated high chromium(VI) removal efficiency over 98%. Besides, fouling of two of the tested nanofiltration membranes (NF1 and NF3) was relatively mitigated after feed pretreatment. Nanofiltration permeation fluxes as high as 80-100L/m(2)h were thereby obtained. The resulting permeate stream quality post nanofiltration (NF3) was found to be suitable for effective reuse in tanneries, keeping the Cr(VI) concentration (0.13mg/L), Biochemical Oxygen Demand (BOD) (65mg/L), Chemical Oxygen Demand (COD) (142mg/L), Total Dissolved Solids (TDS) (108mg/L), Total Solids (TS) (86mg/L) and conductivity levels (14mho/cm) in perspective. The process water reclaiming ability of nanofiltration was thereby substantiated and the effectiveness of the proposed hybrid system was thus affirmed.

Osteopontin deficiency impacts the pancreatic TH1/TH2 cytokine profile following multiple low dose streptozotocin-induced diabetes

Osteopontin (OPN) is a phosphorylated acidic glycoprotein that causes chemotaxis of macrophages and downregulation of nitric oxide synthesis. OPN has been shown to be involved in the pathogenesis of autoimmune diseases. Here, we tested the hypothesis that increased expression of pancreatic OPN in experimental diabetes has a protective role. The immune response phenotype associated with the induction of diabetes was evaluated in male OPN knockout (KO) and wild type (WT) mice. Multiple low dose streptozotocin (STZ) (MLDS), 40 mg/kg, was injected intraperitoneally for 5 days to establish a model for autoimmune diabetes. Glucose levels and body weight were evaluated in the vehicle and STZ treated groups. ELISA assay was used to monitor OPN serum levels in the WT diabetic mice. Histological studies evaluated insulitis development and Western blot analysis was employed to evaluate the expression levels of Th1 cytokines (TNF-alpha and IFN-gamma) and Th2 cytokines (IL-10 and IL-4). Immunohistochemistry was employed to localize IL-4 in the diabetic WT pancreata. Both WT and KO mice developed diabetes. In the WT, OPN serum levels were significantly upregulated 1 day after STZ injection. Pancreatic islets appeared larger in the KO group. Mild lymphocytic infiltrate and apoptosis were detected in the WT diabetic islets, while no signs of inflammation were detected in the KO group. WT diabetics showed upregulation of both Th1 and Th2 cytokines, whereas in the diabetic KO a mild upregulation of Th1 cytokines was detected with significant downregulation of IL-4. In the diabetic WT mice, IL-4 was localized in the interlobular connective tissue. Our studies show that the pancreatic immune response to MLDS diabetes is balanced between the Th1 and Th2 in the WT animals. KO mice show mild polarization towards the Th1 response. Although OPN is a known promoter for Th1 responses, it appears to have a regulatory control over the Th2 response in MLDS.

Streptozotocin (STZ) mediates acute upregulation of serum and pancreatic osteopontin (OPN): a novel islet-protective effect of OPN through inhibition of STZ-induced nitric oxide production

Osteopontin (OPN) is a secreted acidic phosphoprotein that binds to a cell-surface integrin-binding motif and is involved in many inflammatory and immune-modulating disorders. There is compelling evidence that soluble OPN can in a variety of situations help cells survive an otherwise lethal insult. In this study we show that OPN is localized in the rat pancreatic islets and ducts. Staining of pancreatic serial sections with islet hormone antibodies showed that all islet cells express OPN. Rats treated with a single dose of streptozotocin (STZ; 50 mg/kg) showed acute upregulation of serum OPN levels and pancreatic OPN mRNA and protein. Serum OPN dropped by the end of day 7 but was still higher than prediabetic levels. Pancreatic mRNA and protein showed a similar pattern. Twenty-four hours after STZ injection, the intensified OPN expression was localized towards the periphery of the islets and surrounded the remaining insulin-positive cells. To explore the significance of OPN acute upregulation, freshly isolated islets were pretreated with OPN (0.15-15 nM) before addition of STZ. OPN significantly reduced the STZ-induced NO levels in the islets through an Arg-Gly-Asp (RGD)-dependent reduction of inducible NO synthase (iNOS) mRNA levels. Addition of OPN to freshly isolated mildly diabetic islets (blood glucose <300 mg/dl) significantly improved their glucose-stimulated insulin secretion and reduced their NO levels. Next we investigated the regulation of OPN in beta-cells. When STZ (5 mM) was added to the beta-cell line RINm5F it significantly increased OPN mRNA levels within 6 h. To distinguish between the effect of STZ and high glucose on OPN transcription, RINm5F cells were transfected with luciferase-labeled rat OPN promoter and treated with STZ (0.05-5 mM) or with glucose (5-25 mM). STZ induced upregulation of OPN promoter activity within 3 h, while high glucose induced upregulation of OPN promoter activity after 48 h. Our data introduce OPN as a novel islet protein that is differentially regulated by STZ and glucose in the islets. OPN initial upregulation after diabetes induction was probably due to STZ-induced toxicity, while maintenance of the high OPN levels might be due to hyperglycemia. The acute induction of OPN after STZ-induced diabetes might represent an endogenous mechanism to protect the islets against STZ-induced cytotoxicity, partly via an RGD-dependent NO regulatory mechanism.

Osteopontin gene expression and immunolocalization in the rabbit urinary tract

PURPOSE

Osteopontin is a highly phosphorylated, calcium binding sialoprotein characterized by a conserved arginine-glycine-aspartate sequence. Vitronectin receptor (alphavbeta3 integrin) and hyaluronan receptor (CD44) are documented as receptors for osteopontin and their expression has been established in the bladder. Based on that finding and the fact that osteopontin protein is present in urine we hypothesized that osteopontin is expressed in the lower urinary tract.

MATERIALS AND METHODS

Osteopontin messenger (m)RNA and protein were analyzed in 5 adult urinary tracts and 5 neonatal bladders of New Zealand White rabbits using reverse transcriptase-polymerase chain reaction and immunohistochemical testing. Analysis of mRNA expression and localization of osteopontin receptors, alphavbeta3 integrin and CD44 were also performed in adult bladders and primary cultures of detrusor myocytes.

RESULTS

Adult renal pelvis, ureter, bladder and urethra, and neonatal bladders contained significant levels of osteopontin mRNA. Immunohistochemical staining revealed osteopontin expression in all layers of the transitional epithelium of the bladder, co-localizing with alphavbeta3 integrin mainly in the superficial layers and with CD44 mainly in the basal layers. Osteopontin was detected within the cytoplasm of smooth muscle cells, while alphavbeta3 integrin was located closer to the plasmalemma. Furthermore, primary cultured detrusor myocytes expressed osteopontin mRNA in stable fashion for up to 4 passages. Treating bladder myocyte cultures with insulin-like growth factor-1 and 17beta-estradiol resulted in up-regulation and down-regulation of osteopontin mRNA, respectively.

CONCLUSIONS

Adult and neonatal rabbit detrusors are a prominent source of osteopontin in vivo and in vitro. Epithelial osteopontin may be a source of osteopontin in urine. The co-localization of osteopontin in the bladder epithelium with alphavbeta3 integrin and CD44 suggests a role in maintaining the integrity of the transitional epithelium by providing the sealing and adhesiveness needed for the impermeable state of the bladder.

Heterogeneity of bladder myocytes in vitro: modulation of myosin isoform expression

We studied the expression of myosin heavy chain isoforms differing at the N-terminal (SM-A, SM-B) and the C-terminal (SM1, SM2) regions and non-muscle myosin heavy chain II-A and II-B (NMMHC II-A and B) in newborn and adult rabbit bladder smooth muscle cells (SMCs) and in cultures of enzymatically dissociated neonatal detrusor. RT-PCR analyses revealed that 94.5+/-3.27% of MHC transcripts of the adult bladder SMCs contained the 21-nucleotide insert (SM-B) compared with 83.8+/-3.2% in the newborn bladder, with the remainder of the mRNA being non-inserted (SM-A). In 3, 7, and 10 days of primary culture (proliferating, confluent, and post-confluent, respectively) and up to 4 subculture passages, bladder myocytes expressed predominantly SM-A. Immunofluorescence microscopy revealed heterogeneity in cultured myocytes, i.e. SM-B positive cells coexisting with negatively stained cells. In adult bladder, the C-terminal isoforms SM1 and SM2 represented, 43.1+/-4.3% and 56.89 + 4.3% of the mRNA, respectively, while newborn bladders expressed 72.5+/-7% SM1 and 27.5+/-7% SM2. Upon culturing, cells predominantly expressed SM1 at both the mRNA and protein levels. NMMHC II-A was expressed by both adult and newborn bladders and in culture, whereas NMMHC II-B was expressed at low levels only in newborn bladders, but upregulated in culture. These data indicate that bladder myocytes in vitro undergo modulation with relative overexpression of SM-A and SM1 and upregulation of NMMHC II-B. Information on the mechanisms responsible for this modulation in vitro might provide an understanding of the nature of altered myosin isoform expression associated with smooth muscle dysfunction in certain bladder diseases.

Decomposition of hazardous organic materials in the solidification/stabilization process using catalytic-activated carbon

The application of a catalytic-activated carbon to the solidification/stabilization (S/S) process for immobilization of phenol and 2-chlorophenol and catalytic decomposition was investigated. The effect of the catalytic-activated carbon, in amounts of 0.25-1% (by dry sand wt.), on the leaching of phenol and 2-chlorophenol was studied. H2O2 was added as a source of oxygen in the amounts of 1 or 5%, with respect to liquid solution weight. Toxicity characteristic leaching procedure (TCLP) leaching tests showed that adding the catalytic-activated carbon to the S/S matrix significantly reduced the leachability of both phenol and 2-chlorophenol. Only trace amounts of phenol were found in the leaching solution, while the concentration of 2-chlorophenol was below the detection limit of the gas chromatography (GC). Without addition of the catalytic-activated carbon, 87% of the phenol and 92% of the 2-chlorophenol leached. Additional tests on TCLP leachate solutions using GC-mass spectrometry indicated the existence of simple, less hazardous, hydrocarbons, including alcohol. Catalytic-activated carbons treated with phenol in the presence of H2O2 were also analyzed using time of flight-secondary ion mass spectroscopy (TOF-SIMS). Results indicate that the phenol aromatic ring was broken by the catalytic reaction.

Immobilization of phenol in cement-based solidified/stabilized hazardous wastes using regenerated activated carbon: leaching studies

In this research, we investigated the use of an inexpensive thermally regenerated activated carbon as a pre-adsorbent in the solidification/stabilization of phenol-contaminated sand. Our results show that even the addition of very low amounts of regenerated activated carbon (1%-2% w/w sand) resulted in the rapid adsorption of phenol in the Chemical solidification/stabilization (S/S) matrix, with phenol leaching reduced by as much as 600%. Adsorption studies indicated that the adsorption of phenol on the reactivated carbon was found to be partially irreversible over time in the S/S waste form, indicating possible chemical adsorption. Pore-fluid analyses of the cement paste containing phenol suggested the formation of a calcium-phenol complex, which further reduced the amount of free phenol present in the pores. Studies using several micro-structural techniques, including field emission scanning electron microscopy, X-ray diffraction, fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy, indicated significant morphological changes in the cement matrix upon the addition of phenol and reactivated carbon. The hydration of cement in the presence of phenol was retarded concomitant with formation of amorphous portlandite.

Immobilization of phenol in cement-based solidified/stabilized hazardous wastes using regenerated activated carbon: role of carbon

The use of regenerated activated carbon as an immobilizing additive for phenol in solidification/stabilization (S/S) processes was investigated. The adsorption capacity of regenerated carbon was compared to that of the virgin form and was found to be very close. The effects of pH and Ca(OH)(2) concentration within the S/S monolith on the adsorption process were also examined. Kinetic tests were performed to evaluate the adsorption of phenol on different forms of F400 carbon, including the regenerated form. Kinetic tests were performed in aqueous solutions as well as in liquid-sand mixtures. In both cases, it was found that phenol adsorption on F400 carbon was fairly fast. More than 60% of the equilibrium adsorption amount could be achieved within the first hour for aqueous solutions. For sand-solution kinetics, it was found that 1% carbon (based on dry sand weight) was capable of achieving more than 95% removal of the initial amount of phenol present in solution (1000 and 5000 ppm). Fourier transform infrared (FT-IR) spectroscopy and X-ray mapping tests indicated a homogenous mixing of the carbon into the cement matrix. The carbon was also found to enhance the hydration of cement, which was retarded by the existence of phenol.