Preparation of dual-function starch-based flocculants for the simultaneous removal of turbidity and inhibition of Escherichia coli in water

A dual-function starch-based flocculant, carboxymethyl-starch-graft-aminomethylated-polyacrylamide (CMS-g-APAM), was designed and prepared by a simple method. The structure and solution properties of CMS-g-APAM were characterized by fourier transform infrared spectroscopy, (1)H nuclear magnetic resonance, and zeta-potential measurements. CMS-g-APAM was then applied to flocculate a kaolin suspension and an Escherichia coli suspension as well as a combination thereof. At suitable pH conditions, the starch-based flocculant not only effectively removed turbidity but it also disrupted bacterial cells. Interpretation of the zeta potential and floc properties (floc size and two-dimensional fractal structure) showed that, for the aforementioned three effluents, simple charge neutralization was the dominant mechanism of flocculation in acidic medium whereas an additional contribution from a patching effect was determined under neutral conditions. Three-dimensional excitation-emission matrix spectra and direct surface morphology observation under a scanning electron microscope both illuminated that the antibacterial activity of CMS-g-APAM involved the partial destruction of the cell wall of Escherichia coli. The mechanism can be attributed to the effective interaction between the tertiary amine group of the flocculant and the negatively charged surface of the bacterium.

Efficient adsorption of both methyl orange and chromium from their aqueous mixtures using a quaternary ammonium salt modified chitosan magnetic composite adsorbent

A quaternary ammonium salt modified chitosan magnetic composite adsorbent (CS-CTA-MCM) was prepared by combination of Fe3O4 nanoparticles. Various techniques were used to characterize the molecular structure, surface morphology, and magnetic feature of this composite adsorbent. CS-CTA-MCM was employed for the removal of Cr(VI) and methyl orange (MO), an anionic dye, from water in respective single and binary systems. Compared with chitosan magnetic adsorbent (CS-MCM) without modification, CS-CTA-MCM shows evidently improved adsorption capacities for both pollutants ascribed to the additional quaternary ammonium salt groups. Based on the adsorption equilibrium study, MO bears more affinity to CS-CTA-MCM than Cr(VI) causing a considerable extent of preferential adsorption of dye over metal ions in their aqueous mixture. However, at weak acidic solutions, Cr(VI) adsorption is evidently improved due to more efficient Cr(VI) forms, i.e. dichromate and monovalent chromate, binding to this chitosan-based adsorbent. Thus chromium could be efficient removal together with MO at suitable pH conditions. The adsorption isotherms and kinetics indicate that adsorptions of Cr(VI) and MO by CS-CTA-MCM both follow a homogeneous monolayer chemisorption process. This magnetic adsorbent after saturated adsorption could be rapidly separated from water and easily regenerated using dilute NaOH aqueous solutions then virtually reused with little adsorption capacity loss.

On the time value of absolute ruin with debit interest

Assume that the surplus of an insurer follows a compound Poisson surplus process. When the surplus is below zero or the insurer is on deficit, the insurer could borrow money at a debit interest rate to pay claims. Meanwhile, the insurer will repay the debts from her premium income. The negative surplus may return to a positive level. However, when the negative surplus is below a certain critical level, the surplus is no longer able to be positive. Absolute ruin occurs at this moment. In this paper, we study absolute ruin questions by defining an expected discounted penalty function at absolute ruin. The function includes the absolute ruin probability, the Laplace transform of the time to absolute ruin, the deficit at absolute ruin, the surplus just before absolute ruin, and many other quantities related to absolute ruin. First, we derive a system of integro-differential equations satisfied by the function and obtain a defective renewal equation that links the integro-differential equations in the system. Second, we show that when the initial surplus goes to infinity, the absolute ruin probability and the classical ruin probability are asymptotically equal for heavy-tailed claims while the ratio of the absolute ruin probability to the classical ruin probability goes to a positive constant that is less than one for light-tailed claims. Finally, we give explicit expressions for the function for exponential claims.

Propofol attenuated liver transplantation-induced acute lung injury via connexin43 gap junction inhibition

BACKGROUND

Postoperative acute lung injury (ALI) is a severe complication after liver transplantation, which influences patient survival rate obviously. However, its mechanisms are unclear and effective therapies are still lacking. The current study focused on effects of propofol on liver transplantation-induced ALI and whether its underlying mechanism was relative with connexin43 (Cx43) alternation. The authors postulated that endotoxin induced enhancement of Cx43 gap junction (GJ) plays a critical role in mediating post liver transplantation ALI and that pretreatment with the anesthetic propofol, known to inhibit gap junction, can confer effective protection.

METHODS

Male Sprague-Dawley rats underwent autologous orthotopic liver transplantation (AOLT) in the absence or presence of treatments with the selective Cx43 inhibitor, enanthol (0.1 mg/kg) and propofol (50 mg/kg), a commonly used anesthetic in clinical anesthesia. In vitro study, BEAS-2B cells, a kind of lung epithelial cell line expressing Cx43, exposed to lipopolysaccharide (LPS), which mainly contributed to ALI. Function of Cx43 GJ was regulated by Cx43 specific inhibitors, gap26 (300 μM) or enhancer, retinoic acid (10 μM) and two specific siRNAs.

RESULTS

Compared with the sham group, AOLT results in ALI obviously with plasma endotoxin increase. Cx43 inhibition decreased ALI through inflammatory reaction reduction. In vitro studies, LPS-induced BEAS-2B cells damage was attenuated by Cx43 function inhibition, but amplified by enhancement. Another important finding was propofol reduced Cx43 function and protected against LPS-mediated BEAS-2B cells damage or AOLT-induced ALI, mechanisms of which were also associated with inflammatory reaction decrease.

CONCLUSION

Cx43 plays a vital role in liver transplantation-induced ALI. Propofol decreased Cx43 function and protected against ALI in vivo and in vitro. This finding provide a new basis for targeted intervention of organ protection in liver transplantation, even in other kinds of operations.

Telmisartan Ameliorates Nephropathy in Metabolic Syndrome by Reducing Leptin Release From Perirenal Adipose Tissue

Metabolic syndrome (MetS) is associated with nephropathy. Along with common risk factors such as hypertension and hyperglycemia, adipocytokines released from perirenal adipose tissue (PRAT) are implicated in the pathogenesis of MetS nephropathy. The study was designed to elucidate the adverse effects of PRAT-derived leptin on nephropathy and to determine whether the angiotensin II type 1 receptor antagonist telmisartan exerts a renoprotective effect by decreasing the PRAT-derived leptin level in the high-fat diet-induced MetS rat. In MetS rats, PRAT-derived leptin expression increased concomitant with dysfunction of adipogenesis, and the activities of the angiotensin II-angiotensin II type 1 receptor and the angiotensin-converting enzyme 2-angiotensin (1-7)-Mas receptor axes were imbalanced in PRAT. PRAT-derived leptin from MetS rats promoted proliferation of rat glomerular endothelial cells (GERs) by activating the p38 MAPK (mitogen-activated protein kinase) pathway, thereby contributing to the development of nephropathy. Long-term telmisartan treatment improved metabolic parameters and renal function, decreased the amount of PRAT, promoted adipogenesis, increased the expression of angiotensin-converting enzyme 2, restored balanced activities of the angiotensin II-AT1R and angiotensin-converting enzyme 2-angiotensin (1-7)-Mas axes, and exerted an indirect renoprotective effect on MetS rats by decreasing PRAT-derived leptin release. Our results demonstrate a novel link between nephropathy and PRAT in MetS and show that telmisartan confers an underlying protective effect on visceral adipose tissue and the kidney, suggesting that it has potential as a therapeutic agent for the treatment of MetS-associated nephropathy.

Establishment of a new cell line from the snout tissue of golden pompano Trachinotus ovatus, and its application in virus susceptibility

A new marine-fish cell line, designated GPS, was established from the snout tissue of golden pompano Trachinotus ovatus. GPS cells multiplied well in Leibovitz's L-15 containing 10% foetal bovine serum (FBS) at 28° C and the cells have been subcultured for >60 passages. Polymerase chain reaction (PCR) amplification of 16S ribosomal (r)RNA confirmed the origin of this cell line from T. ovatus. Chromosome analysis showed that GPS cells exhibited chromosomal aneuploidy with a modal chromosome number of 54. Bright green fluorescence signal was observed in enhanced green fluorescent protein (EGFP)-N3 transfected cells, indicating that GPS cells could be used to investigate gene functions in vitro. The GPS cells were highly susceptible to Singapore grouper iridovirus (SGIV), which was demonstrated by the presence of severe cytopathic effect (CPE) and increased viral titres. Real-time quantitative PCR and Western blot analysis showed that the viral gene transcription and protein synthesis occurred during SGIV infection in GPS cells. Thus, this study described the characteristic of a new cell line from the snout tissue of T. ovatus that could be used as a tool for propagation of iridovirus and genetic manipulation to investigate host-pathogen interactions.

Orai1, a Direct Target of microRNA-519, Promotes Progression of Colorectal Cancer via Akt/GSK3β Signaling Pathway

BACKGROUND

Orai1, which is involved in store-operated calcium entry, has recently been implicated in cancer progression. However, the role of Orai1 in colorectal cancer (CRC) progression remains unclear.

METHODS

We used real-time PCR and western blot to measure Orai1 expression in four CRC cell lines, 60 tumor pairs, and corresponding non-tumor tissues from CRC patients. Immunohistochemistry was performed to examine Orai1 expression in CRC and corresponding non-tumor tissues. Statistical analyses were applied to evaluate the prognostic value and associations of Orai1 expression with clinical parameters. Furthermore, the Orai1 gene was overexpressed in HCT116 cell and silenced with siRNA in LOVO cell. Moreover, cell proliferation and apoptosis were measured using MTT assay and flow cytometry, and a molecular mechanism of Orai1 regulation by miR-519 was explored.

RESULTS

Orai1 expression was higher in CRC tissues than adjacent non-cancerous tissues, and this was positively correlated in CRC patients with distant metastasis and poor prognosis. Also, increased expression of Orai1 was observed in highly invasive CRC cell lines and ectopic expression of Orai1 enhanced cell proliferation and inhibited apoptosis; silencing Orai1 suppressed cell proliferation and induced apoptosis. The Akt/GSK3β pathway contributed to Orai1 effects in CRC cells, and Orai1 was a direct target of miR-519, a microRNA not previously reported to be involved in both CRC tissues and cell lines.

CONCLUSIONS

We identified a novel CRC regulatory circuit involving the miR-519-Orai1 axis, and dysfunction of this drives diverse aspects of CRC pathogenesis.