Preliminary assessment of various additives on the specific reactivity of anti- rHBsAg monoclonal antibodies

Background: Antibodies have a wide application in diagnosis and treatment. In order to maintain optimal stability of various functional parts of antibodies such as antigen binding sites, several approaches have been suggested. Using additives such as polysaccharides and polyols is one of the main methods in protecting antibodies against aggregation or degradation in the formulation. The aim of this study was to evaluate the protective effect of various additives on the specific reactivity of monoclonal antibodies (mAbs) against recombinant HBsAg (rHBsAg) epitopes. Methods: To estimate the protective effect of different additives on the stability of antibody against conformational epitopes (S3 antibody) and linear epitopes (S7 and S11 antibodies) of rHBsAg, heat shock at 37°C was performed in liquid and solid phases. Environmental factors were considered to be constant. The specific reactivity of antibodies was evaluated using ELISA method. The data were analyzed using SPSS software by Mann-Whitney nonparametric test with the confidence interval of 95%. Results: Our results showed that 0.25 M sucrose, 0.04 M trehalose and 0.5% BSA had the most protective effect on maintaining the reactivity of mAbs (S3) against conformational epitopes of rHBsAg. Results obtained from S7 and S11 mAbs against linear characteristics showed minor differences. The most efficient protective additives were 0.04 M trehalose and 1 M sucrose. Conclusion: Nowadays, application of appropriate additives is important for increasing the stability of antibodies. It was concluded that sucrose, trehalose and BSA have considerable effects on the specific reactivity of anti rHBsAg mAbs during long storage. © 2015, Avicenna Journal of Medical Biotechnology. All rights reserved

SMOKE AND VAPOR PLUME MERGENCE

Observations at power plants have indicated that vapor plumes emitted from cooling towers frequently merge with smoke plumes released from stacks. Mergence of cooling tower and stack plume leads to formation of acidic compounds which have adverse effects on the en- vironment. Wind speed and direction play an important role in merging smoke and vapor plume. This paper lists some arguments to verify that studies have not sufficiently addressed stack and cooling tower plume mergence. In conclusion, the present authors hope to find more information in the future with regard to vapor and smoke plume mergence

On a Linear Program for Minimum-Weight Triangulation

Minimum-weight triangulation (MWT) is NP-hard. It has a polynomial-time constant-factor approximation algorithm, and a variety of effective polynomial- time heuristics that, for many instances, can find the exact MWT. Linear programs (LPs) for MWT are well-studied, but previously no connection was known between any LP and any approximation algorithm or heuristic for MWT. Here we show the first such connections: for an LP formulation due to Dantzig et al. (1985): (i) the integrality gap is bounded by a constant; (ii) given any instance, if the aforementioned heuristics find the MWT, then so does the LP.Comment: To appear in SICOMP. Extended abstract appeared in SODA 201

A novel hydrogen peroxide biosensor based on modified electrode with hemoglobin and zinc oxide nanoparticles

In this study, direct electron transfer between immobilized hemoglobin (Hb) and zinc oxide nanoparticles modified carbon paste electrode was studied. Direct electrochemical response of Hb on the modified electrode can be achieved and a couple of well-defined and nearly reversible cyclic voltammetric peaks of Hb can be observed in a phosphate solution. The Hb immobilized on the Modified electrode with Zno Nps displayed a pair of redox peaks in 0.1 M pH 7.0 PBS with a formal potential of + (292 ± 2) mV (vs. SCE). Hb adsorbed on the modified electrode surface shows a good activity for the reduction of hydrogen peroxide (H2O2). The reduction peak currents were proportional linearly to the concentration of hydrogen peroxide. The Hb/ Zno Nps/ CPE had good repeatability and stability for the determination of H2O2

Synthesis of the erythromycin-conjugated nanodendrimer and its antibacterial activity

Abstract The development and spread of bacterial resistance to antimicrobial drugs necessitates the need to search for novel and effective antimicrobial agents. In the last few decades, innovative nanomaterials are attracting increasing attention and, among them, dendrimers have shown wide application in the various fields. In the current study, the two generations of an anionic linear- spherical nanodendrimer G1 and G2 were synthetized and compound G2 of nanodendrimer conjugated with erythromycin. The structures of the nanodendrimers were characterized by FTIR spectroscopy, zetasizer, and scanning electron microscopy (SEM). The antibacterial activity of the erythromycin-conjugated nanodendrimer and erythromycin alone were evaluated by the microdilution method against Staphylococcus aureus, S. epidermidis, S. saprophyticus, and Pseudomonas aeruginosa. The size of first and second generation of nanodendrimer, and the erythromycin-conjugated nanodendrimer was 75, 95, and 65.6 nm, respectively. The drug loading percentage of the nanodendrimer conjugates was obtained to be in 35.2%. In our study, the erythromycin-conjugated nanodendrimer showed significantly more bacteriostatic and bactericidal activities against all four studied bacteria than erythromycin alone. Our study's results highlight that the erythromycin-conjugated nanodendrimer is a highly effective agent against Gram positive and negative bacteria. The antibacterial properties of erythromycin combined with the targeting potential of the nanodendrimer can lead to sustained intracellular delivery of therapeutic agent Keywords: Nanostructures Erythromycin Dendrimers Antibacterial agents

Folate-conjugated nanoparticles as a potent therapeutic approach in targeted cancer therapy

The selective and efficient drug delivery to tumor cells can remarkably improve different cancer therapeutic approaches. There are several nanoparticles (NPs) which can act as a potent drug carrier for cancer therapy. However, the specific drug delivery to cancer cells is an important issue which should be considered before designing new NPs for in vivo application. It has been shown that cancer cells over-express folate receptor (FR) in order to improve their growth. As normal cells express a significantly lower levels of FR compared to tumor cells, it seems that folate molecules can be used as potent targeting moieties in different nanocarrier-based therapeutic approaches. Moreover, there is evidence which implies folate-conjugated NPs can selectively deliver anti-tumor drugs into cancer cells both in vitro and in vivo. In this review, we will discuss about the efficiency of different folate-conjugated NPs in cancer therapy. © 2015, International Society of Oncology and BioMarkers (ISOBM)

A Near-Global Atmospheric Distribution of N2O Isotopologues

The distributions of the four most abundant isotopologues and isotopomers (N2O, 15NNO, N15NO, and NN18O of nitrous oxide have been measured in the Earth\u27s stratosphere by infrared remote sensing with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer. These satellite observations have provided a near-global picture of N2O isotopic fractionation. The relative abundances of the heavier species increase with altitude and with latitude in the stratosphere as the air becomes older. The heavy isotopologues are enriched by 20-30% in the upper stratosphere and even more over the poles. These observations are in general agreement with model predictions made with the Whole Atmosphere Community Climate Model (WACCM). A detailed 3-D chemical transport model is needed to account for the global isotopic distributions of N2O and to infer sources and sinks

Anticancer activity of Sargassum oligocystum water extract against human cancer cell lines

Background and Objectives: Antitumor drug resistance and side effects of antitumor compounds are the most common problems in medicine. Therefore, finding new antitumor agents with low side effects could be interesting. This study was designed to assay antitumor activity of the extract from brown alga Sargassum oligocystum, gathered from Persian Gulf seashore, against K562 and Daudi human cancer cell lines. Materials and Methods: The research was performed as an in vitro study. The effect of the alga extract on proliferation of cell lines were measured by two methods: MTT assay and trypan blue exclusion test. Results and Conclusion: The most effective antitumor activity has been shown at concentrations 500 μg/ml and 400 μg/ml of the alga extract against Daudi and K562 cell lines, respectively. The results showed that the extracts of brown alga Sargassum oligocystum have remarkable antitumor activity against K562 and Daudi cell lines. It is justified to be suggested for further research such as algal extract fractionation and purification and in vivo studies in order to formulate natural compounds with antitumor activities