Optimization of the fermentation conditions and partial characterization for acido-thermophilic α-amylase from Aspergillus niger NCIM 548

Ghasem Najafpour Darzi,Pouya Sirous Rezaei,Hoda Shafaghat 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.3

A high performance thermostable α-amylase at low pH values has been synthesized. Sugarcane bagasse was hydrolyzed in a dilute acid solution and utilized as carbon source for the growth of Aspergillus niger strain NCIM 548. Glucose, xylose and arabinose with the ratio of 1.0 : 0.9 : 0.3 (w/w/w) were detected in the hydrolyzate by HPLC analysis. Optimization of the fermentation conditions for α-amylase production was performed by varying four influential parameters such as Sugarcane bagasse hydrolyzate (SBH), NH4Cl, pH and incubation time using a central composite design (CCD) under response surface methodology (RSM). The optimum values of SBH, NH4Cl, pH and incubation time were 20.49, 2.34 g/l, 5.65 and 76.67 h, respectively. The acido-thermophilic enzyme showed maximum stability at 70 oC and pH value of 4. The rate constant, Km and maximum reaction rate, Vmax were 18.79 g/l and 15.85 g/l·min,respectively.

Conceptual Design and Analysis of Steel-Concrete

Suhaib Yahya Kasim Al-Darzi,Airong Chen 한국강구조학회 2006 International Journal of Steel Structures Vol.6 No.5

deck connections and the effects of their interaction. First, analysis and design methods of composite bridge structures,conections betwen components, the reliability and life cycle of bridges, new concrete-steel bridge system forms, and thedevelopment of alternative materials used in composite bridges were reviewed with some potential applications. The conceptualideas on new forms of connectors and the application of holow core slab decks in composite bridge structures were alsopresented.

Quantum Chemical Studies of Some Sulphanilamide Schiff Bases Inhibitor Activity Using QSAR Methods

Baher, Elham,Darzi, Naser,Morsali, Ali,Beyramabadi, Safar Ali Korean Chemical Society 2015 대한화학회지 Vol.59 No.6

The different calculated quantum chemical descriptors by DFT method were used for prediction of some sulphanilamide Schiff bases inhibitor activity as a binding constant (log K). Multiple linear regression (MLR) and artificial neural network (ANN) were employed for developing the useful quantitative structure activity relationship (QSAR) model. The obtained results presented superiority of ANN model over the MLR one. The offering QSAR model is very easy to computation and Physico-Chemically interpretable. Sensitivity analysis was used to determine the relative importance of each descriptor in ANN model. The order of importance of each descriptor according to this analysis is: molecular volume, molecular weight and dipole moment, respectively. These descriptors appear good information related to different structure of sulphanilamide Schiff bases can participate in their inhibitor activity.

Removal of melanoidin from molasses spent wash using fly ash-clay adsorbents

Ali Ramezani,Ghasem Najafpour Darzi,Maedeh Mohammadi 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4

Removal of melanoidin pigment from molasses spent wash was investigated using a new adsorbent. Solid adsorbents were fabricated from charcoal fly ash and clay. The effect of various molasses concentration (6 to 12 g/l)on removal efficiency was studied. The obtained results revealed that maximum removal efficiency of 82% was achieved at the molasses concentration of 6 g/l and contact time of 7 h. The saturated porous adsorbents were regenerated and reused to conduct similar experiments. The achieved data showed that more than 90% of the capacity of the fresh adsorbent was recovered after regeneration. Various adsorption isotherms of Langmuir, Freundlich, Temkin and Harkins-Jura were applied to interpret the obtained experimental data. The obtained results revealed that the sorption data were well described by the Harkins-Jura model. Also, various kinetic models of pseudo-first order, pseudo-second order,Elovich and intra-particle diffusion were used to predict the characteristic parameters which are useful in process design. It was concluded that the best fit was obtained with pseudo-second order kinetic model at low molasses concentrations.

Thionine Increases Electricity Generation from Microbial Fuel Cell Using Saccharomyces cerevisiae and Exoelectrogenic Mixed Culture

Mostafa Rahimnejad,Ghasem Darzi Najafpour,Ali Asghar Ghoreyshi,Farid Talebnia,Giuliano C. Premier,Gholamreza Bakeri,김중래,오상은 한국미생물학회 2012 The journal of microbiology Vol.50 No.4

Microbial fuel cells (MFCs) have been shown to be capable of clean energy production through the oxidation of biodegradable organic waste using various bacterial species as biocatalysts. In this study we found Saccharomyces cerevisiae,previously known electrochemcially inactive or less active species, can be acclimated with an electron mediator thionine for electrogenic biofilm formation in MFC, and electricity production is improved with facilitation of electron transfer. Power generation of MFC was also significantly increased by thionine with both aerated and non-aerated cathode. With electrochemically active biofilm enriched with swine wastewater, MFC power increased more significantly by addition of thionine. The optimum mediator concentration was 500 mM of thionine with S. cerevisae in MFC with the maximum voltage and current generation in the microbial fuel cell were 420 mV and 700 mA/m2, respectively. Cyclic voltametry shows that thionine improves oxidizing and reducing capability in both pure culture and acclimated biofilm as compared to non-mediated cell. The results obtained indicated that thionine has great potential to enhance power generation from unmediated yeast or electrochemically active biofilm in MFC.

Manganese ferrite (MnFe2O4) Nanoparticles: From synthesis to application -A review

Neda Akhlaghi,Ghasem Najafpour Darzi 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Manganese ferrite (MnFe2O4) nanoparticle, a spinel ferrite nanomaterial, is one of the important magneticmetal oxide nanoparticles with distinctive physical and chemical properties. This nanoparticlecan be easily synthesized through various methods with controllable size and desired morphology. MnFe2O4 is an efficient candidate for various applications like biomedical, analytical, and storage devices. In this review, several synthesis methods and physicochemical properties of MnFe2O4 nanoparticles arediscussed. Then, a comprehensive overview of the latest and most promising researches on massiveapplications of MnFe2O4-based nanostructures, including hyperthermia cancer therapy, magnetic resonanceimaging (MRI), energy conversion and storage devices like Lithium-ion batteries and supercapacitors,as well as catalytic activities, sensors, hydrogen production, heavy metal removal, and drug deliveryare presented. Overall, herein, a deep understanding of the unlimited ability of MnFe2O4 nanoparticles indiverse applications is provided.

Design of novel hyper-branched dendritic boehmite/gallic acid alumoxane for methylene blue removal: Adsorption mechanism and reusability

Fatemeh Banisheykholeslami,Morteza Hosseini,Ghasem Najafpour Darzi,Mohammad Reza Shirzad Kebria 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.4

A novel hyper-branched alumoxane with dendritic structure (Alu-Den) was prepared via a polycondensation reaction between hydroxyl groups of boehmite and carboxylic groups of gallic acid for use as an adsorbent for elimination of cationic Methylene blue from aqueous media. The successful formation of tree-like structure of Alu-Den was confirmed by several analyses, including FTIR, XRD, FE-SEM, BET, DLS and TGA. Adsorption variables, such as adsorbent dosage and pH, were optimized to acquire the maximum efficiency for dye removal. The results indicated that 0.02 g Alu-Den can totally eliminate 10 ml Methylene blue with concentration of 20 mg/l at 288 K and pH=10. In case of visionary investigation, the sorption process conformed to the pseudo-second-order kinetic model for all prepared concentrations. The Langmuir, Freundlich and Sips isotherms were evaluated to define the interaction between dye molecules and dendritic alumoxane structures. The results showed that the empirical data were in agreement with the Sips isotherm. Additionally, the spontaneous and exothermic quiddity of Methylene blue adsorption onto Alu-Den surface was divulged by thermodynamics assessments. Eventually, the Alu-Den was regenerated following four time adsorption-desorption cycles without significant loss in adsorption capacity. Hence, owing to its biocompatibility, simply accessible precursors, and high recyclability, the present novel adsorbent offered superior potential for the elimination of cationic dyes from aqueous phase.

Optimization of protease production process using bran waste using Bacillus licheniformis

Amin Heydari Espoui,Saeedeh Gilani Larimi,Ghasem Najafpour Darzi 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.3

Protease enzyme production by Bacillus licheniformis bacteria was investigated. Various agricultural wastes as substrate such as wheat bran, rice bran, and sugarcane bagasse were considered. The most important effective parameters on enzyme production, like incubation time, various substrates and solid substrate particle size, media pH, different nitrogen sources in a bench-scale designed bioreactor, were optimized. The optimum protease production conditions, for both Erlenmeyer flask and batch bioreactor, at 37 oC, pH of 8, incubation time of 48h, wheat bran (5 wt%) with the particle size of 1mm, an equal amount of peptone and yeast extract (1% w/w) and agitation rate of 180 rpm were defined. In addition, maximum protease activity in the Erlenmeyer flask and batch bioreactor was 596 and 683.93U/mL, respectively. The pH and thermal stability of produced protease were studied; the highest amount of remaining activities at pH 8 and 60 oC were 97 and 63% of initial activities, respectively. Also, shelf-life of the produced protease enzyme retained up to 88% of its initial activity after 30 days of storage at 4 oC. However, the produced enzyme was exposed remarkably compatible with the commercial detergent; the enzyme perfectly washed and removed the stains from the sample cotton textile.

Dry-powder form of chitosan nanospheres containing influenza virus and adjuvants for nasal immunization

S. Dehghan,M. Tavassoti Kheiri,M. Tabatabaiean,S. Darzi,M. Tafaghodi 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.8

The objective of this study was to develop andstatistically optimize chitosan nanospheres. For this purposechitosan powder was turned into nanospheres using tripolyphosphateas a crosslinker and through ionic gelation. D-optimal response surface design was applied to optimizethe nanospheres. Their size and polydispersity index (PDI)were measured as the dependant variables. Then the inactivatedinfluenza virus and/or CpG ODN or Quillaja saponin(QS) were incorporated into the chitosan nanospheres. Therelease profiles of the antigen and both adjuvants wereobtained. The toxicity of the formulations was tested byXTT using Calu 6 cell lines. The size distribution and PDIof plain chitosan nanospheres was 581.1 ± 32.6 and0.478 ± 0.04. After 4 h the release of antigen, QS and CpGfrom the chitosan matrix were 33, 36 and 62 %, respectively. The inactivated virus remained intact during preparation,as revealed by the SDS-PAGE method. Differentialscanning calorimetry and Fourier Transform InfraredSpectroscopy indicated no serious structural changes in thechitosan carrier in the presence of either the antigen or theimmunoadjuvants. Although the antigen loaded into chitosannanospheres showed slight cytotoxicity on lung-cancercells, co-encapsulation of the adjuvant (especially CpG)lowered this effect. The results demonstrated that chitosanas a carrier and immunostimulator, along with CpG or QSadjuvants, creates a potential influenza vaccine deliverysystem which can be administered nasally.

Fifty Years of Innovation in Plastic Surgery

Kwasnicki, Richard M,Hughes-Hallett, Archie,Marcus, Hani J,Yang, Guang-Zhong,Darzi, Ara,Hettiaratchy, Shehan Korean Society of Plastic and Reconstructive Surge 2016 Archives of Plastic Surgery Vol.43 No.2

Background Innovation has molded the current landscape of plastic surgery. However, documentation of this process only exists scattered throughout the literature as individual articles. The few attempts made to profile innovation in plastic surgery have been narrative, and therefore qualitative and inherently biased. Through the implementation of a novel innovation metric, this work aims to identify and characterise the most prevalent innovations in plastic surgery over the last 50 years. Methods Patents and publications related to plastic surgery (1960 to 2010) were retrieved from patent and MEDLINE databases, respectively. The most active patent codes were identified and grouped into technology areas, which were subsequently plotted graphically against publication data. Expert-derived technologies outside of the top performing patents areas were additionally explored. Results Between 1960 and 2010, 4,651 patents and 43,118 publications related to plastic surgery were identified. The most active patent codes were grouped under reconstructive prostheses, implants, instruments, non-invasive techniques, and tissue engineering. Of these areas and other expert-derived technologies, those currently undergoing growth include surgical instruments, implants, non-invasive practices, transplantation and breast surgery. Innovations related to microvascular surgery, liposuction, tissue engineering, lasers and prostheses have all plateaued. Conclusions The application of a novel metric for evaluating innovation quantitatively outlines the natural history of technologies fundamental to the evolution of plastic surgery. Analysis of current innovation trends provides some insight into which technology domains are the most active.