Novel carbon nano-fibers (CNF)/polysulfone (PSf) mixed matrix membranes for gas separation

Mohsen Jahanshahi,Ahmad Rahimpour,Mohsen Jahanshahi,Ali Asghar Ghoreyshi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-

Mixedmatrixmembranes (MMM) included of carbon nanofibers (CNFs) fabricated and characterized forgas separation performance. For preparation of MMM, carbon nanofibers content was varied from 0.01 to1 wt% in polysulfone (PSf) casting solution. The fabricated CNFs/PSF MMMs characterized by scanningelectron microscopy (SEM), atomic force microscopy (AFM), ATR–FTIR spectra and pure gas permeationand sorption test. The gas transport properties ofMMMmeasured using single gas permeation set up (N2,O2, CO2, and CH4) at ambient temperature and different feed pressures. Additionally, sorption isothermsformixed matrixmembranesmade for CH4 and CO2. The sorption data were analyzed by the dual-modesorption model. Themorphological studies show that the incorporation of CNFs appreciably changed thesurface properties of membranes. The permeation test showed that the mixed matrix membraneexhibited high permeability. With increasing CNF concentration, CNFs/PSF membrane permeabilityraised from 2.134 to 12.04 Barrer for CO2. The results found that this unique membrane had increasedpermeability and enhanced selectivity. Also it has a great potential to be used practically in gasseparation technology.

Protective effects of Ginkgo biloba extract (EGB 761) on astrocytes of rat hippocampus after exposure with scopolamine

Mehrdad Jahanshahi,EmseGol Nikmahzar,Negin Yadollahi,Kamyar Ramazani 대한해부학회 2012 Anatomy & Cell Biology Vol.45 No.2

The regular extract of Ginkgo biloba has been shown to possess neuroprotective properties in disorders like hypoxia, ischemia, seizure activity and peripheral nerve damage. Also, G. biloba has received attention as a potential cognitive enhancer for the treatment of Alzheimer’s disease, but there is not any documentation about the effect of an extract of G. biloba on astrocytes. Th erefore, the aim of this study was examined the effects of G. biloba extract on the rat’s hippocampal astrocytes after scopolamine based amnesia. In this study, 36 adult male Wistar rats were used. Rats were randomly distributed into control, sham, protective and treatment groups. The rats in the sham group only received scopolamine hydrobromide (3 mg/kg)intraperitoneally. The rats in the protective and treatment groups received G. biloba extract (40, 80 mg/kg) for 7 days intraperitoneally before and after scopolamine injection. Forty eight hours after the last injection, the brains of the rats were withdrawn and fixed with paraformaldehide, and then after histological processing, the slices were stained with phosphotungstic acid-haematoxylin for astrocytes. Data were analyzed by the analysis of variance (ANOVA) post hoc Tukey test; P<0.05 was considered significant. Results showed that scopolamine can reduce the number of astrocytes in all areas of hippocampal formation compared with the control. However, G. biloba extract can compensate for the reduction in the number of astrocytes in the hippocampus before or after the encounter with scopolamine. We concluded that a pretreatment and treatment injection of G. biloba extract can have a protective effect for astrocytes in all areas of hippocampal formation.

Designing a Non-invasive Surface Acoustic Resonator for Ultra-high Sensitive Ethanol Detection for an On-the-spot Health Monitoring System

Peyman Jahanshahi,Qin Wei,Zhang Jie,Erfan Zal Nezhad 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.4

Surface acoustic wave (SAW) sensors – based on piezoelectric crystal resonators – are extremely sensitive to even very small perturbations in the external atmosphere, because the energy associated with the acoustic waves is confined to the crystal surface. In this study, we present a critical review of the recent researches and developments predominantly used for SAW-based organic vapor sensors, especially ethanol. Besides highlighting their potential to realize real-time ethanol sensing, their drawbacks such as indirect sensing, invasive, time initializing, and low reliability, are properly discussed. The study investigates a proposed YZ-lithium niobate piezoelectric substrate with interdigital transducers patterned on the surface. Design of the resonator plays an important role in improving mass sensitivity, particularly the sensing area. Accordingly, a tin dioxide (SnO2) layer with a specific thickness is generated on the surface of the sensor because of its high affinity to ethanol molecules. To determine the values of sensor configuration without facing the practical problems and the long theoretical calculation time, it is shown that the mass sensitivity of SAW sensors can be calculated by a simple three-dimensional (3-D) finite element analysis (FEA) using a commercial finite-element platform. In design validation step, different concentrations of ethanol are applied to investigate the acoustic wave properties of the sensor. The FEA data are used to obtain the surface and bulk total displacements of the sensor and fast Fourier transform (FFT) on output spectrum. The sensor could develop into highly sensitive and fast responsive structure so that a positive intensity shift of 0.18e-2 RIU is observed when the sensor is exposed to 15 ppm ethanol. It is capable of continuously monitoring the ethanol gas whether as an ultra-high sensitive sensor or switching applications for medical and industrial purposes.

FIBONACCI SEQUENCES ON MV -ALGEBRAS

Morteza Afshar Jahanshahi,Arsham Borumand Saeid 한국수학교육학회 2018 純粹 및 應用數學 Vol.25 No.4

In this paper, we introduce the concept of Fibonacci sequences on MV - algebras and study them accurately. Also, by introducing the concepts of periodic sequences and power-associative MV -algebras, other properties are also obtained. The relation between MV -algebras and Fibonacci sequences is investigated.

Free vibration analysis of combined system with variable cross section in tall buildings

Mohammad Reza Jahanshahi,Reza Rahgozar 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.5

This paper deals with determining the fundamental frequency of tall buildings that consist of framed tube, shear core, belt truss and outrigger systems in which the framed tube and shear core vary in size along the height of the structure. The effect of belt truss and outrigger system is modeled as a concentrated rotational linear spring at the belt truss and outrigger system location. Many cantilevered tall structures can be treated as cantilevered beams with variable cross-section in free vibration analysis. In this paper, the continuous approach, in which a tall building is replaced by an idealized cantilever continuum representing the structural characteristics, is employed and by using energy method and Hamilton’s variational principle, the governing equation for free vibration of tall building with variable distributed mass and stiffness is obtained. The general solution of governing equation is obtained by making appropriate selection for mass and stiffness distribution functions. By applying the separation of variables method for time and space, the governing partial differential equation of motion is reduced to an ordinary differential equation with variable coefficients with the assumption that the transverse displacement is harmonic. A power-series solution representing the mode shape function of tall building is used. Applying boundary conditions yields the boundary value problem; the frequency equation is established and solved through a numerical process to determine the natural frequencies. Computer program has been developed in Matlab (R2009b, Version 7.9.0.529, Mathworks Inc., California, USA). A numerical example has been solved to demonstrate the reliability of this method. The results of the proposed mathematical model give a good understanding of the structure’s dynamic characteristics; it is easy to use, yet reasonably accurate and suitable for quick evaluations during the preliminary design stages.

Antibacterial dynamic membranes loaded by cephalexin/amine-functionalized SBA_15 for Pb(II) ions removal

Maryam Darzipour,Mohsen Jahanshahi,Majid Peyravi,Soodabeh Khalili 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.12

Novel antibacterial dynamic membranes loaded by cephalexin/amine functionalized SBA_15 were fabricated for heavy metal removal from aqueous solution. The mesoporous CPX/NH2-SBA_15 nanocomposite was formed as a uniform adsorptive and hydrophilic layer on the ultrafiltration polymeric membrane (PVDF). The modified adsorbent and membranes were characterized by SEM, XRD, N2 adsorption-desorption analysis, FT-IR, TGA, DSC and contact angle. A number of qualitative (well diffusion, disk diffusion) antibacterial assays were conducted against grampositive S. aureus and gram-negative E. coli. In addition, to evaluate its anti-biofouling performance, the model concentrated bacteria suspension in liquid medium was used as a feed solution. 100% bacteria mortality for certain concentration and suitable inhibition zones up to 3.5cm were attained. An increment in the flux recovery from 55% (for UF) to 87% (for self-forming dynamic membrane (DM)) and 91% (for pre-coated DM) indicated that the dynamic layer improved the anti-biofouling property of the support membrane. High Pb(II) removal efficiency (99.8%) was achieved for the modified membrane during dynamic filtration test. CPX/NH2/SBA-15 dynamic membrane showed higher Pb2+ rejection than SBA-15 dynamic membrane because of amine groups located on the adsorbent surface. In general, membranes provide good performance like better flux and rejection besides antibacterial and anti-biofouling behavior.

Feasibility study of a novel copolyamide thin film composite membrane assisted by melamine in terms of acid and thermal stability

Hamzeh Hoseinpour,Mohsen Jahanshahi,Majid Peyravi,Ahmad Nozad 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.46 No.-

A new acid stable copolyamide [PEI-Mel]-PA membrane was developed via interfacial polymerizationassisted by melamine. The physico-chemical properties and separation ability were studied. It wascompared with an acid stable polysulfonamide membrane in terms of acid stability. Melamine improvedthe thermal and acid stability and made the surface of the membrane more positively charged. Thedecreases in MgSO4 rejections were 56% and 31% for [PEI-Mel]-PA membrane after H2SO4 and HNO3treatment, respectively. The stability of [PEI-Mel]-PA improved up to 16% and 48% in H2SO4 and HNO3,respectively in comparison with PEI-PA membrane. It recovered more than 97% of the acid.

A new electrochemical biosensor for hydrogen peroxide using HRP/AgNPs/cysteamine/p-ABSA/GCE self-assembly modified electrode

Ali Shokuhi Rad,Mohsen Jahanshahi,Mehdi Ardjmand,Ali-Akbar Safekordi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

An electrochemical hydrogen peroxide biosensor was designed by immobilizing horseradish peroxidase (HRP) on Ag nanoparticles/cysteamine/p-aminobenzene sulfonic acid/glassy carbon (GC) electrode. Ag nanoparticles can act as tiny conduction centers on electrodes that adsorb redox enzymes, facilitating the transfer of electrons with no requiring any loss of biological activity. The forerunner film was first electropolymerized on the glassy carbon electrode with p-aminobenzene sulfonic acid (p-ABSA) by cyclic voltammetry. The cysteamine (CA) was bound on the surface of the film by electrostatic force, then Ag nanoparticles were immobilized on the cysteamine monolayer, and lastly HRP was adsorbed onto the surfaces of the Ag nanoparticles. A dramatic decrease in the overvoltage of H2O2was observed with improved sensitivity, which makes the modified electrodes of great promise for oxidase-based amperometric biosensors. The biosensor responded to H2O2 in the linear range from 1.2×106 mol/L to 9.8×103 mol/L with a detection limit of 1.1×108 mol/L. Moreover, the obtained biosensor exhibited good accuracy and high sensitivity.

Hippocampal serotonin-2A receptor– immunoreactive neurons density increases after testosterone therapy in the gonadectomized male mice

Emsehgol Nikmahzar,Mehrdad Jahanshahi,Amir Ghaemi,Gholam Reza Naseri,Ali Reza Moharreri,Ahmad Ali Lotfinia 대한해부학회 2016 Anatomy & Cell Biology Vol.49 No.4

The change of steroid levels may also exert different modulatory effects on the number and class of serotonin receptors present in the plasma membrane. The effects of chronic treatment of testosterone for anxiety were examined and expression of 5-HT 2A serotonergic receptor, neuron, astrocyte, and dark neuron density in the hippocampus of gonadectomized male mice was determined. Thirty-six adult male NMRI mice were randomly divided into six groups: intact-no testosterone treatment (No T), gonadectomy (GDX)-No T, GDX-Vehicle, GDX-6.25 mg/kg testosterone (T), GDX-12.5 mg/kg T, and GDX-25 mg/kg T. Anxiety-related behavior was evaluated using elevated plus maze apparatus. The animals were anesthetized after 48 hours after behavioral testing, and decapitated and micron slices were prepared for immunohistochemical as well as histopathological assessment. Subcutaneous injection of testosterone (25 mg/kg) may induce anxiogenic-like behavior in male mice. In addition, immunohistochemical data reveal reduced expression of 5-HT 2A serotonergic receptor after gonadectomy in all areas of the hippocampus. However, treatment with testosterone could increase the mean number of dark neurons as well as immunoreactive neurons in CA1 and CA3 area, dose dependently. The density of 5-HT 2A receptor–immunoreactive neurons may play a crucial role in the induction of anxiety like behavior. As reduction in such receptor expression have shown to significantly enhance anxiety behaviors. However, replacement of testosterone dose dependently enhances the number of 5-HT 2A receptor–immunoreactive neurons and interestingly also reduced anxiety like behaviors.

Olfactory neuropathology in Alzheimer’s disease: a sign of ongoing neurodegeneration

( Gowoon Son ),( Ali Jahanshahi ),( Seung-jun Yoo ),( Jackson T. Boonstra ),( David A. Hopkins ),( Harry W. M. Steinbusch ),( Cheil Moon ) 생화학분자생물학회(구 한국생화학분자생물학회) 2021 BMB Reports Vol.54 No.6

Olfactory neuropathology is a cause of olfactory loss in Alzheimer’s disease (AD). Olfactory dysfunction is also associated with memory and cognitive dysfunction and is an incidental finding of AD dementia. Here we review neuropathological research on the olfactory system in AD, considering both structural and functional evidence. Experimental and clinical findings identify olfactory dysfunction as an early indicator of AD. In keeping with this, amyloid-β production and neuro-inflammation are related to underlying causes of impaired olfaction. Notably, physiological features of the spatial map in the olfactory system suggest the evidence of ongoing neurodegeneration. Our aim in this review is to examine olfactory pathology findings essential to identifying mechanisms of olfactory dysfunction in the development of AD in hopes of supporting investigations leading towards revealing potential diagnostic methods and causes of early pathogenesis in the olfactory system. [BMB Reports 2021; 54(6): 295-304]