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Lipopolysaccharide (LPS), as a stubborn contamination, should be monitored and kept in an acceptable level during the pharmaceutical production process. Recombinant hepatitis B surface antigen (r-HBsAg) is one of the recombinant biological products, which is probable to suffer from extrinsic endotoxin due to its long and complex production process. This research aims to assess the potential interaction between LPS and r-HBsAg by recruiting immunoaffinity chromatography (IAC) as a novel tool to quantify the interaction. Molecular modeling was performed on the HBsAg molecule to theoretically predict its potential binding and interaction sites. Then dynamic light scattering (DLS) analysis was implemented on HBsAg, LPS, and mixtures of them to reveal the interaction. The virus-like particle (VLP) structure of HBsAg and the ribbon-like structure of LPS were visualized by transmission electron microscopy (TEM). Finally, the interaction was quantified by applying various LPS/HBsAg ratios ranging from 1.67 to 120 EU/dose in the IAC. Consequently, the LPS/HBsAg ratios in the eluate were measured from 1.67 to a maximum of 92.5 EU/dose. The results indicated that 77 to 100% of total LPS interacted with HBsAg by an inverse relationship to the incubated LPS concentration. The findings implied that the introduced procedure is remarkably practical in the quantification of LPS interaction with a target recombinant protein.

Various industries ranging from water purification to pharmaceutical production have experienced multi separation steps that impose more process time and contamination possibility by batch operation. We propose a developed microfluidic particle sorter (miniaturized hydrocyclone) that adopts centrifugal force as it has ability to decline the number of separation steps and the risk of extrinsic contamination in continuous process. While biological industries have not relied on mini hydrocyclones considerably because of low efficiency and microfabrication difficulties, current work has been planned to conquer these obstacles. In this research, biomass separation from fermentation broth by 3 mm hydrocyclones was investigated. The effect of apex size, feed flow rate, hydrocyclone geometry were analyzed numerically in four mini-hydrocyclones. The most efficient mini-hydrocyclone was chosen to be made by elegant additive manufacturing technology and studied experimentally. The separation efficiency was achieved up to 90% while the concentration ratio of heavy stream (apex) to dilute stream (vortex finder) was reached more than twofold. The mini hydrocyclone performance in view of energy target was studied by Euler-Reynolds-Efficiency plots. The 4 μm cut size was achieved that is promising high throughput separation for biological particles.

Delay in inpatient discharge processes reduces patient satisfaction and increases hospital congestion and length of stay. Further, flow congestion manifests as patient boarding, where new patients awaiting admission are blocked by bed unavailability. Finally, length of stay is extended if the discharge delay incurs an extra overnight stay. These factors are often in conflict, thus, good hospital performance can only be achieved through careful balancing. We formulate the discharge planning problem as a two-stage stochastic program with uncertain discharge processing and bed request times. The model minimizes a combination of discharge lateness, patient boarding, and deviation from preferred discharge times. Patient boarding is integrated by aligning bed requests with bed releases. The model is solved for different instances generated using data from a large hospital in Texas. Stochastic decomposition is compared with the extensive form and the L-shaped algorithm. A shortest expected processing time heuristic is also investigated. Computational experiments indicate that stochastic decomposition outperforms the L-shaped algorithm and the heuristic, with a significantly shorter computational time and small deviation from optimal. The L-shaped method solves only small problems within the allotted time budget. Simulation experiments demonstrate that our model improves discharge lateness and patient boarding compared to current practice.

For a finite group G, let R(G) be the solvable radical of G. The character-graph Δ(G) of G is a graph whose vertices are the primes which divide the degrees of some irreducible complex characters o...

The aim of this research was to optimize and model the synthesis and application of a novel visible-light-driven Ag/C-TiO2 nanophotocatalyst for degradation of recombinant DNA in Hepatitis B surface antigen production plant wastewater. The synthesized nanoparticles were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis diffuse reflectance spectra, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The effects of the dopant content of silver and carbon, calcination temperature, heating rate, initial recombinant DNA copy number, pH value, and contact time were evaluated experimentally and optimized separately as the synthesis and operational parameters. Application of response surface methodology showed the optimum values of Ag content, C content, calcination temperature, and the heating rate as 2.2 wt%, 0.06 wt%, 444 °C, and 12 °C/min, respectively. Synthesized nanoparticles resulted in 60% recombinant DNA degradation at the optimized operation conditions experimentally (i.e., pH of 5.5, contact time of 24 h, and the maximum initial recombinant DNA concentration of 2.12E13 copy number in 200 mL wastewater). The synthesis and operating quadratic models adequately predicted the experimental data. The statistical analysis showed that the square of carbon dopant content, calcination temperature, initial recombinant DNA concentration, and contact time had the greatest effects on the recombinant DNA degradation.

There is a growing interest in the biopharmaceutical industry to enhance production efficiency via shifting batch to continuous manufacturing. In the previous study, we demonstrated that under identical operation condition, continuous fermentation of recombinant Pichia pastoris (P. pastoris) Mut+ producing intracellular hepatitis B surface antigen (HBsAg) has considerably higher efficiency compared to the conventional fed-batch process. In the current work, by examining various dilution rates, we further optimized the process efficiency, and also determined some strain-specific parameters. According to the results, continuous operation at the dilution rate of 0.015 1/h demonstrated the highest performance compared to other dilution rates of 0.009, 0.02, 0.25, 0.03 and 0.0417 1/h. In the optimum dilution rate, the average HBsAg titer, yield, specific and volumetric productivity were 283.9 mg HBsAg/L, 0.71 mg HBsAg/g MeOH, 0.0097 mg HBsAg/g wet cell weight (WCW)/h and 4.26 mg HBsAg/L/h, respectively. Compared to the continuous fermentation in the previous study, the volumetric and specific productivities were improved by the factors of 2.0 and 2.5, respectively. Following Herbert-Pirt linear relation between specific growth rate and methanol consumption rate, the obtained biomass yield and maintenance coefficient in the continuous fermentation were 1.22 (g WCW/g MeOH) and 0.008 (g MeOH/g WCW/h), respectively. The consistency in the process condition and efficiency without any genetic instability and contamination in the one-month operation- in each fermentation run- suggests that the studied recombinant strain could be one of the potential candidates for continuous biomanufacturing of hepatitis B vaccine.

The aggregation of recombinant proteins in the different stages of purification leads to the loss of a considerable portion of target protein and reduction in the process efficiency. As the active HBsAg used in Hepatitis B vaccine production is in the form of virus-like particle (VLP), therefore the time and stages at which the VLP assembling happened through the process would be important. The aim of this study was to explore the product aggregation during different stages of large scale production of rHBsAg in Pichia pastoris at production unit of the Pasteur Institute of Iran. Dynamic light scattering (DLS) and transmission electron microscopy (TEM), and also size exclusion-high-performance liquid chromatography (SE-HPLC) were carried out on samples taken from each downstream processes steps to determine the rate of VLPs formation as the desired product and the aggregated form at each stage of the purification. Based on the results, it was found that VLPs formation started at the acid precipitation stage and reached up to 80% at the thermal treatment stage. The ultrafiltration, ion exchange chromatography and immunoaffinity chromatography stages were disclosed to have the highest contribution in the formation of VLP (virus like particle) 22 nm.

In the current work, the attempt was made to apply best-fitted artificial neural network (ANN) architecture and the respective training process for predicting final titer of hepatitis B surface antigen (HBsAg), produced intracellularly by recombinant Pichia pastoris Mut+ in the commercial scale. For this purpose, in large-scale fed-batch fermentation, using methanol for HBsAg induction and cell growth, three parameters of average specific growth rate, biomass yield, and dry biomass concentration-in the definite integral form with respect to fermentation time-were selected as input vectors; the final concentration of HBsAg was selected for the ANN output. Used dataset consists of 38 runs from previous batches; feed-forward ANN 3:5:1 with training algorithm of backpropagation based on a Bayesian regularization was trained and tested with a high degree of accuracy. Implementing the verified ANN for predicting the HBsAg titer of the five new fermentation runs, excluded from the dataset, in the full-scale production, the coefficient of regression and root-mean-square error were found to be 0.969299 and 2.716774, respectively. These results suggest that this verified soft sensor could be an excellent alternative for the current relatively expensive and time-intensive analytical techniques such as enzyme-linked immunosorbent assay in the biopharmaceutical industry.

Production of recombinant HBsAg as a main component of the hepatitis B vaccine has already been established in commercial scale. So far, many studies have been performed to optimize the production process of this recombinant vaccine. However, still aggregation and dissociation of rHBsAg virus-like particles (VLPs) are major challenges in downstream processing of this biomedicine. The structural diversity of rHBsAg is dependent on many factors including cell types, molecular characteristics of the expressed recombinant rHBsAg, buffer composition as well as operation condition and specific characteristics of each downstream processing unit. Hence, it is not relatively easy to implement a single strategy to prevent aggregation formation in already established rHBsAg production processes. In this study, we examined the efficacy of weak anion exchange chromatography (IEC)- packed with DEAE Sepharose Fast Flow medium- on isolation of rHBsAg VLPs from aggregated structures. For this purpose, the influence of ionic strength of elution buffer as a key factor was investigated in isolation and recovery of rHBsAg VLPs. The elution buffer with electrical conductivity between 27 and 31 mS/cm showed the best results for removing aggregated rHBsAg based on SEC-HPLC analysis. The results showed that in the selected conductivity range, about 79% of rHBsAg was recovered with purity above 95%. The percentage of rHBsAg VLPs in the recovered sample was between 94% and 97.5% indicating that we could obtain highly homogeneous rHBsAg within the acceptable quality level. The TEM, SDS-PAGE and western blot analysis were also in agreement with our quantitative measurements.

In purification process of recombinant hepatitis B surface antigen (rHBsAg), immunoaffinity chromatography (IAF) is one of the most important and effective steps in rHBsAg purification. However, the buffer composition and the interaction of ligands-rHBsAg often lead to disassembly, deformation, and clumping of a portion of these virus-like particles (VLPs). Besides, the expensive media, variable biospecific ligand density and the possibility of product contamination are other reported drawbacks of using IAF which makes the production process of rHBsAg more challenging. This study investigated the possibility of substituting IAF with purification methods of size-exclusion chromatography (SEC) and ultracentrifugation. In the SEC, the efficacy of rHBsAg purification was examined by four different media in which Toyopearl HW 65S resin demonstrated the best results. By integrating Toyopearl HW 65S resin - with a bed height of 51 cm - and ultracentrifugation process at 47,000 rpm for 48 hr, 95% of protein impurities were removed. Compared to the IAF in rHBsAg production, the purified sample contained a higher percentage of multimeric rHBsAg particles without any noticeable monomer and aggregate forms. The result of this study indicates that the proposed integrated system could be an efficient mild purification alternative for conventional IAF.

In our previous study, we demonstrated that continuous power laser could be a clean, rapid, and convenient alternative to the other conventional disruption techniques for the release of recombinant hepatitis B surface antigen (rHBsAg) from Pichia pastoris. In the current work, we examined the effect of pulsed laser in the continuous laboratory-scale process on cell disruption. Design-of-experiments (DOE) methodology was used for optimization of cell disruption process to obtain the highest protein concentration in the disruption buffer. Our investigations for the pulsed laser at wavelength of 1,064 nm demonstrated that for disrupting P. pastoris cell and releasing rHBsAg, the laser power was the most influential factor, and laser pulse duration and cycle number were in the second and third places. According to the results, the effect of laser power and pulse duration (time) had a direct relationship with protein concentration. For the number of cycles, however, increasing the value from the lowest point at first led to the enhancement and then reduction of protein concentration. The maximum cell disruption and rHBsAg release were recorded for the laser system in the energy input of 284 mW and the pulse duration of 100 mSec after four complete rounds of circulation.

In the downstream process of recombinant hepatitis B surface antigen (rHBsAg), nano-colloidal silica adsorbent (Aerosil-380) is one of the possible methods to separate the antigen from other main impurities partially. The current study aimed to maximize the adsorptive capacity of Aerosil-380 as well as rHBsAg recovery for large-scale production of recombinant hepatitis B vaccine. The experimental design methodology was used to optimize the eight critical parameters influencing the efficiency, rHBsAg recovery, of the adsorption-desorption process in the lab-scale. These examined parameters were the adsorption-desorption temperature, pH, contact time, agitation speed, antigen concentration, and desorption buffer. Under optimal condition, the maximum adsorption capacity of Aerosil-380 was equal to 3333 μg.g

In the production process of recombinant Hepatitis B surface antigen (rHBsAg) various separation techniques are used to purify this virus-like particle (VLP). In this study, we developed antibody-conjugated super-paramagnetic Fe3O4/SiO2 core-shell nanoparticles as a highly selective method for isolation of expressed rHBsAg in yeast Pichia pastoris. For this purpose, first, iron oxide magnetic nanoparticles (MNPs) were prepared by co-precipitation method in alkali media and coated with silica. Then the surface was activated by amine groups and conjugated with oxidized antibodies. X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) were used to study the physical properties of MNPs. To evaluate the efficacy of these MNPs as a purification technique successfully synthesized MNPs were added to the rHBsAg sample to couple with the antigen and then be isolated based on their magnetic property. In the present research, in the optimum condition, we could isolate 65% of total rHBsAg from the final vaccine sample with purity above 95%. In this procedure, the maximum obtained specific yield (mg HBsAg/mg MNPs) was equal to 37.6. These results underline the potential application of the immune-magnetic separation (IMS) in the future bioseparation systems.

This paper describes the construction of a silver-based LSPR biosensor for endotoxin detection. We used GLAD method to procure reproducible silver nanocolumns. In this work, the silver nanostructures were considerably stabilized by a SAM of MPA, and the limit of detection of biosensor was measured to be 340 pg/ml for endotoxin E. coli. Considering endotoxin B. abortus as the second type of endotoxin contamination in our target samples (HBs-ag produced in Institute Pasteur, Iran), we investigated selectivity of the biosensor in various experiments. We showed that this biosensor can selectively detect both types of endotoxins compared to other biological species. Overall, this study proposes that LSPR biosensing can be considered as a sensitive, simple, and label-free method for endotoxin detection in the quality control laboratories.

In biotechnological processes, often cell disruption has been an inevitable step as current host cells express most of the desired products intracellularly. Thus, an appropriate cell disruption technique must be selected considering different factors including the target product, process scale, and cell wall structure. In the current study, as a novel method, the efficacy of cell disruption via laser was tested qualitatively and quantitatively in batch and continuous systems, respectively. Laser-induced cell lysis can be a clean, rapid and convenient alternative to the other conventional disruption techniques. Our investigations in the continuous system with a flow rate of 800 μL/sec proved efficient (~ 90%) Pichia pastoris cell disruption at the wavenumber 1,064 nm with the energy input of 284 mW after four complete rounds of circulation. The main mechanism of cell disruption is assumed to be thermolysis via instant heat increase in the laser-treated spot. The results of the current study showed that continuous laser system could be applied in laboratory and industry scale for cell disruption.

Let G be a finite group. An element g ∈ G is called a vanishing element if there exists an irreducible complex character χ of G such that χ(g)= 0. Denote by Vo(G) the set of orders of vanishing elements of G. Ghasemabadi, Iranmanesh, Mavadatpour (2015), in their paper presented the following conjecture: Let G be a finite group and M a finite nonabelian simple group such that Vo(G) = Vo(M) and |G| = |M|. Then G ≌ M. We answer in affirmative this conjecture for M = Sz(q), where q = 22n+1 and either q − 1, \(q - \sqrt {2q} + 1\) or q + \(\sqrt {2q} + 1\) is a prime number, and M = F4(q), where q = 2 n and either q4 + 1 or q4 − q2 + 1 is a prime number.

In biopharmaceutical science, ion-exchange chromatography (IEC) is a well-known purification technique to separate the impurities such as host cell proteins from recombinant proteins. However, IEC is one of the limiting steps in the purification process of recombinant hepatitis B surface antigen (rHBsAg), due to its low recovery rate (

Alpha-1-antitrypsin (A1AT) is a major serum protein in human with protease inhibitory activity. Because of its extensive application in medicine, recombinant DNA technology has been considered for its production. The current study examines coexpression of A1AT and soluble domain of v-SNARE in Pichia pastoris, which can prevent the secretion of A1AT after thoroughly passing the secretory pathway. This was done mainly to preserve the biological activity of A1AT, which in the secretory mode might be impaired in the fermentation and early clarification conditions. SNARE proteins are the driving force for vesicle docking and membrane fusion in the exocytosis. Intracellular expression of the cytoplasmic domain of v-SNARE and its subsequent interaction to form SNARE complex can intensify the competition for A1AT secretory vesicles to be fused and released to the media. Our investigation shows successful coexpression of A1AT in the form of post-Golgi vesicles and the cytoplasmic domain of v-SNARE. Our findings confirmed the reduction of A1AT secretion by 45% caused accumulation of post-Golgi secretory vesicles filled with A1AT inside the yeast cell. A1AT trapped in secretory vesicles were biologically more active than secretory A1AT. These results indicate that the inhibition of A1AT secretion can protect its biological activity in fermentation and clarification processes.

In mammalian cell culture technology, viral contamination is one of the main challenges; and, so far, various strategies have been taken to remove or inactivate viruses in the cell-line production process. The suitability and feasibility of each method are determined by different factors including effectiveness in target virus inactivation, maintaining recombinant protein stability, easiness-in terms of the process condition, cost-effectiveness, and eco-friendliness. In this research, Taguchi design-of-experiments (DOE) methodology was used to optimize a non-detergent viral inactivation method via considering four factors of temperature, time, pH, and alcohol concentration in an unbiased (orthogonal) fashion with low influence of nuisance factors. Herpes Simplex Virus-1 (HSV1) and Vero cell-line were used as models for enveloped viruses and cell-line, respectively. Examining the cytopathic effects (CPE) in different dilutions showed that pH (4), alcohol (15%), time (120 min), and temperature (25 °C) were the optimal points for viral inactivation. Evaluating the significance of each parameter in the HSV-1 inactivation using Taguchi and ANOVA analyses, the contributions of pH, alcohol, temperature and time were 56.5%, 19.2%, 12%, and 12%, respectively. Examining the impact of the optimal viral treatment condition on the stability of model recombinant protein-recombinant human erythropoietin, no destabilization was detected.

Let G be a finite group and cs(G) be the set of conjugacy class sizes of G. In 1987, J. G. Thompson conjectured that, if G is a finite group with Z(G) = 1 and M is a nonabelian simple group satisfying that cs(G) = cs(M), then G ≅ M. This conjecture has been proved for Suzuki groups in [5]. In this article, we improve this result by proving that, if G is a finite group such that cs(G) = cs(Sz(q)), for q = 22m+1, then G ≅ Sz(q) × A, where A is abelian. We avoid using classification of finite simple groups in our proofs.

For a finite group [Formula: see text], let [Formula: see text] be the character-graph which is built on the set of irreducible complex character degrees of [Formula: see text]. In this paper, we wish to determine the structure of finite groups [Formula: see text] such that [Formula: see text] is [Formula: see text]-connected with nonbipartite complement. Also, we classify all [Formula: see text]-connected graphs with nonbipartite complement that can occur as the character-graph [Formula: see text] of a finite group [Formula: see text].

The costly media, inconsistent ligand density, ligand leakage, and possible destabilization of recombinant hepatitis B surface antigen (rHBsAg) particles are main drawbacks of using immunoaffinity chromatography (IAF) in the large-scale downstream processing. In this study, we aimed to use an efficient large-scale purification system as an alternative purification method for immunoaffinity chromatography. For this purpose, we suggested integrating non-affinity chromatographic methods of hydrophobic interaction chromatography (HIC) and size-exclusion chromatography (SEC) for cost-effective purification of rHBsAg expressed in P. pastoris. The optimization of such process is not trivial and straightforward since diverse molecular characteristics of expressed rHBsAg in each type of host cell cause different interactions in non-affinity chromatography processes. The working buffer composition and chromatography parameters are the most influential factors in hydrophobic interaction chromatography. The best result for lab-scale HIC was achieved by using ammonium sulfate buffer in 10% of saturation concentration in pH 7.0 with Butyl-S Sepharose 6 Fast Flow medium and with subsequent Tween-100 and urea elution. In this process, the recovery, purity, and total yield were about 84%, 82%, and 69%, respectively. By scaling-up the HIC and integrating it with Sephacryl S-400 SEC, we obtained highly pure, i.e., 90%, rHBsAg virus-like particles (VLP).

In our previous study, we demonstrated that continuous power laser could be a clean, rapid, and convenient alternative to the other conventional disruption techniques for the release of recombinant hepatitis B surface antigen (rHBsAg) from Pichia pastoris. In the current work, we examined the effect of pulsed laser in the continuous laboratory-scale process on cell disruption. Design-of-experiments (DOE) methodology was used for optimization of cell disruption process to obtain the highest protein concentration in the disruption buffer. Our investigations for the pulsed laser at wavelength of 1,064 nm demonstrated that for disrupting P. pastoris cell and releasing rHBsAg, the laser power was the most influential factor, and laser pulse duration and cycle number were in the second and third places. According to the results, the effect of laser power and pulse duration (time) had a direct relationship with protein concentration. For the number of cycles, however, increasing the value from the lowest point at first led to the enhancement and then reduction of protein concentration. The maximum cell disruption and rHBsAg release were recorded for the laser system in the energy input of 284 mW and the pulse duration of 100 mSec after four complete rounds of circulation.

This paper attempts to design a reverse supply chain network (SCN), add it to an existing multi-product forward SCN and simultaneously redesign the existing forward supply chain (SC). The problem considers uncertainty on products demand and and also returned products in multi-period context. Benders’ decomposition is applied to solve the stochastic mixed-integer model to optimality. The scenarios are generated based on the demand distribution function using Cholesky’s factorization method to consider correlation among different products’ demands. To decrease the computational effort, the number of scenarios is reduced using k-means clustering algorithm. The method is tested on a cell phone SC.

In the production process of recombinant Hepatitis B surface antigen (rHBsAg) various separation techniques are used to purify this virus-like particle (VLP). In this study, we developed antibody-conjugated super-paramagnetic Fe

Alpha-1-antitrypsin (A1AT) is a major serum protein in human with protease inhibitory activity. Because of its extensive application in medicine, recombinant DNA technology has been considered for its production. The current study examines coexpression of A1AT and soluble domain of v-SNARE in Pichia pastoris, which can prevent the secretion of A1AT after thoroughly passing the secretory pathway. This was done mainly to preserve the biological activity of A1AT, which in the secretory mode might be impaired in the fermentation and early clarification conditions. SNARE proteins are the driving force for vesicle docking and membrane fusion in the exocytosis. Intracellular expression of the cytoplasmic domain of v-SNARE and its subsequent interaction to form SNARE complex can intensify the competition for A1AT secretory vesicles to be fused and released to the media. Our investigation shows successful coexpression of A1AT in the form of post-Golgi vesicles and the cytoplasmic domain of v-SNARE. Our findings confirmed the reduction of A1AT secretion by 45% caused accumulation of post-Golgi secretory vesicles filled with A1AT inside the yeast cell. A1AT trapped in secretory vesicles were biologically more active than secretory A1AT. These results indicate that the inhibition of A1AT secretion can protect its biological activity in fermentation and clarification processes.

This paper proposes a model for obnoxious waste location-routing problem (LRP) considering various types of wastes and several treatment technologies. The investigated distribution network includes three echelons of generation nodes, treatment and disposal facilities. A multi-objective LRP model is developed with three objective functions minimizing the treatment and disposal facility undesirability, different costs related to the problem, and eventually the risk associated with transportation of untreated materials. An effective memetic algorithm is developed in which a tabu search algorithm performs the local search. Comparison of exact and meta-heuristic methods run times confirms that the proposed method is effective. Eventually, the developed algorithm is tested on a real-life case study.

Considerable advances have been made in developing human papillomaviruses (HPV) prophylactic vaccines based on L1 virus-like particles (VLPs). However, there are limitations in the availability of these vaccines in developing countries, where most cases of cervical cancer occur. In the current study, the prime-boost immunization strategies were studied using a DNA vaccine carrying HPV-16 L1 gene (pcDNA/L1) and insect cell baculovirus-derived HPV-16 L1 VLP. The humoral immunity was evaluated by measuring the specific IgG levels, and the T-cell immune response was assessed by measuring different cytokines such as IFN-γ, TNF-α and IL-10. Results showed that although immunization with pcDNA/L1 alone could induce strong cellular immune responses, higher immunogenicity especially antibody response was achieved in pcDNA/L1 priming-VLP boosting regimen. Therefore, we suggest that prime-boost regimen can be considered as an efficient prophylactic and therapeutic vaccine.

The purpose of this study was to compare adsorptive capacity of three kinds of celite for r-HBsAg. The experimental design methodology was used to optimize the parameters which affect adsorption efficiency. The examined parameters were the adsorption/desorption temperature, pH, time, agitation speed and antigen concentration. Maximum adsorbed/desorbed efficiency for Celite-A, Celite-B and Celite-C were obtained in optimum parameters, 78%, 45% and 88% respectively. Batch shaking experiments were performed to examine the effects of initial solution pH, agitation speed, contact time and initial antigen concentrations. The maximum adsorption capacity for hepatitis B antigen was obtained 66.2 μg g −1 , 32.4 μg g −1 and 72.6 μg g −1 for Celite-A, Celite-B and Celite-C in case of experimental optimal conditions, respectively. The results indicated that Langmuir isotherm provide the best correlation of experimental data for Celite-A and Celite-C, while the Freundlich isotherm better fitted to experimental data for Celite-B. Results also indicated antigen adsorption onto the celite is best represented with a pseudo second-order kinetic model. Surface characterization was performed by FTIR and FESEM analysis.

Let G be a nite group. The prime graph Γ( G ) of G is de ned as follows. The vertices of Γ( G ) are the primes dividing the order of G and two distinct vertices p, p′ are joined by an edge if G has an element of order pp′ . Let L = D n ( q ) have disconnected prime graph and q ∈ {2; 5}. In this paper, we determine nite groups G with the same prime graph as L , i.e. Γ( G ) = Γ( L ). Keywords: Prime graph, simple group, recognition, quasirecognition Quaestiones Mathematicae 36(2013), 517-535

Muchos autores introdujeron algunas caracterizaciones de los grupos finitos. En este trabajo como principal resultado se demuestra que grupo finito PGL(2, q) es determinado nicamente por su grafica no conmutativa. Tambien se demuestra que PGL(2, q) es caracterizable por su grafico no ciclico. A lo largo de la prueba de estos resultados se demuestra que PGL(2,Q) es determinado unicamente por los componentes de su orden y con ello damos respuesta positiva a una conjetura de Thompson y otra conjetura de Shi Bi y para el grupo PGL(2, q)

Let G be a finite group and N be a normal subgroup of G. Suppose that the set of G-conjugacy class sizes of N is {1, m, n}, with m < n and m does not divide n. In this paper, we show that N is solvable, and we determine the structure of these subgroups., A. Beltran and M. J. Felipe are supported by Proyecto MTM2007-68010-C03-03, by Proyecto MTM2010-19938-C03-02 and by Proyecto GV-2009-021. A. Beltran is also supported by grant Fundacio Caixa-Castello P11B2008-09.

Let G be a nite group. The prime graph ..(G) of G is de ned as follows. The vertices of ..(G) are the primes dividing the order of G and two distinct vertices p and p�� are joined by an edge if there is an element in G of order pp��. It is proved that Dn(q), with disconnected prime graph, is quasirecognizable by their element orders. In this paper as the main result, we show that Dn(3), where n 2 fp; p+1g for an odd prime p > 3, is quasirecognizable by its prime graph.

Let G be a finite group. The prime graph Γ(G) of G is defined as follows. The vertices of Γ(G) are the primes dividing the order of G and two distinct vertices p, p′ are joined by an edge if there is an element in G of order pp′. In [G. Y. Chen et al., Recognition of the finite almost simple groups PGL2(q) by their spectrum, Journal of Group Theory, 10 (2007) 71–85], it is proved that PGL(2, pk), where p is an odd prime and k > 1 is an integer, is recognizable by its spectrum. It is proved that if p > 19 is a prime number which is not a Mersenne or Fermat prime and Γ(G) = Γ(PGL(2, p)), then G has a unique nonabelian composition factor which is isomorphic to PSL(2, p). In this paper as the main result, we show that if p is an odd prime and k > 1 is an odd integer, then PGL(2, pk) is uniquely determined by its prime graph and so these groups are characterizable by their prime graphs.

Let G be a group and π e (G) be the set of element orders of G. Let $${k\in\pi_e(G)}$$ and m k be the number of elements of order k in G. Let $${{\rm nse}(G) = \{m_k|k\in\pi_e(G)\}}$$ . In Shen et al. (Monatsh Math, 2009), the authors proved that $${A_4\cong {\rm PSL}(2, 3), A_5\cong \rm{PSL}(2, 4)\cong \rm{PSL}(2,5)}$$ and $${A_6\cong \rm{PSL}(2,9)}$$ are uniquely determined by nse(G). In this paper, we prove that if G is a group such that nse(G) = nse(PSL(2, q)), where $${q\in\{7,8,11,13\}}$$ , then $${G\cong {PSL}(2,q)}$$ .

As the main result, we show that if G is a finite group such that Γ(G) = Γ(2F4(q)), where q = 22m+1 for some m ≧ 1, then G has a unique nonabelian composition factor isomorphic to 2F4(q). We also show that if G is a finite group satisfying |G| =|2F4(q)| and Γ(G) = Γ(2F4(q)), then G ≅ 2F4(q). As a consequence of our result we give a new proof for a conjecture of W. Shi and J. Bi for 2F4(q).