Uniform Micellization: The Key to Enhanced Mechanical Strength and Swelling Efficiency of Chitosan Hydrogel

Bijan Nasri-Nasrabadi,Akif Kaynak,Cynthia Wong,Pejman Heidarian,Khashayar Badii,Abbas Z. Kouzani 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1

The fabrication of hydrophilic porous hydrogel, with high mechanical strength and good uptake capacity is desirable for a broad range of applications such as drug delivery and liquid sensors. The usual methods are limited to the production of structures with high density of covalently crosslinked networks that restricts the polymer chain rearrangement, resulting in non-uniformed pore size distribution. Covalent networks also limit the activity of functional groups and influence the uptake properties of the polymer. In this study, we proposed simple cyclic cryogelation for the fabrication of hydrogels with uniform pore sizes via controlling the micellization and crystal formation. The chitosan based hydrogels ionically crosslinked with 8 % (w/v) of tripoli phosphate sodium (TPP) displayed high Young’s modulus (63 MPa) after cyclic freezethawing. The liquid uptake capacity of the samples treated with 8 % (w/v) TPP solution at pH 4 showed a slight decrease of about 29 % in comparison to that of non-cyclic processed samples (36 %).

A Generalization of Cohen-Macaulay Modules by Torsion Theory

Bijan Zadeh, M . H .,Payrovi, SH . 호남수학회 1998 호남수학학술지 Vol.20 No.1

In this short note we study the torsion theories aver a commutative ring R and discuss a relative dimension related to such theories for R-modules. Let σ be a torsion functor and (T, F) be its corresponding partition of Spec(R). The concept of σ-Cohen Macaulay (abbr. σ-CM) module is defined and some of the main points concerning the usual Cohen-Macaulay modules are extended. In particular it is shown that if M is a non-zero σ-CM module over R and S is a multiplicatively closed subset of R such that, for all minimal element of T, S ∩ p = Φ, then S^(-1)M is a S^(-1)σ-CM module over S^(-1)R, where S^(-1)σ is the direct image of Q under the natural ring homomorphism R→S^(-1) R.

Quadratic residue codes over Z_9

Bijan Taeri 대한수학회 2009 대한수학회지 Vol.46 No.1

A subset of n tuples of elements of Z_9 is said to be a code over Z_9 if it is a Z_9-module. In this paper we consider an special family of cyclic codes over Z_9, namely quadratic residue codes. We define these codes in term of their idempotent generators and show that these codes also have many good properties which are analogous in many respects to properties of quadratic residue codes over finite fields. A subset of n tuples of elements of Z_9 is said to be a code over Z_9 if it is a Z_9-module. In this paper we consider an special family of cyclic codes over Z_9, namely quadratic residue codes. We define these codes in term of their idempotent generators and show that these codes also have many good properties which are analogous in many respects to properties of quadratic residue codes over finite fields.

IDEAL THEORY OF SUBTRACTION SEMIGROUPS BASED ON (3, 2)-FUZZY SETS

( Bijan Davvaz ),( John Britto Princivishvamalar ),( Neelamegarajan Rajesh ),( Balasubramaniyan Brundha ) 한국수학교육학회 2023 純粹 및 應用數學 Vol.30 No.3

In this paper, we define the notions of (3, 2)-fuzzy ideal of subtraction semigroup and near subtraction semigroup. Also, we discuss some of its properties with examples.

Designing Unicode-compliant Indic-script based Institutional Digital Repository with special reference to Bengali

Bijan Kumar Roy,Subal Chandra Biswas,Parthasarathi Mukhopadhyay 건국대학교 지식콘텐츠연구소 2018 International Journal of Knowledge Content Develop Vol.8 No.3

Molecular investigation of amine performance in the carbon capture process: Least squares support vector machine approach

Bijan Rezaei,Siavash Riahi,Ali Ebrahimpoor Gorji 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1

The growing threat of global warming has raised more attention towards carbon capture. Current amine plants used for carbon removal suffer from great costs inflicted by high energy demand of the solvent regeneration step. Recently, looking for amines with proper performance in reduced temperatures has been the subject of many researches. Clearly, conducting these researches without any criterion and based only on trial and error wastes large amounts of money and time; thus, it is highly needed that the effect of different amine structural parameters be studied on the amine’s cyclic capacity. Quantitative structure property relationship (QSPR) provides an effective method for predicting amines capacity for CO2 absorption. In this work, density functional theory (DFT) was employed for optimization of the molecular geometries, and linear and nonlinear models based on parameters related to the molecular structure are presented. The value of the square of the correlation coefficient (R2) for the MLR and SVM models are 0.894 and 0.973, respectively. Developed models can be used as a criterion for amine selection. Reliability and high predictability of the models are confirmed based on statistical tests. Moreover, mechanistic interpretation of models for better understanding of the reaction mechanism of carbon capture was discussed.

DERIVATION AND ACTOR OF CROSSED POLYMODULES

Bijan Davvaz,Murat Alp 한국수학교육학회 2018 純粹 및 應用數學 Vol.25 No.3

An old result of Whitehead says that the set of derivations of a group with values in a crossed G-module has a natural monoid structure. In this paper we introduce derivation of crossed polymodule and actor crossed polymodules by using Lue's and Norrie's constructions. We prove that the set of derivations of a crossed polygroup has a semihypergroup structure with identity. Then, we consider the polygroup of invertible and reversible elements of it and we obtain actor crossed polymodule.

Co-Administration of Subeffective Anxiolytic Doses of Diazepam and Hydroxyzine in Elevated Zero-Maze in Mice

Bijan Naghibi,Farhoud Rayatnia 대한신경정신의학회 2011 PSYCHIATRY INVESTIGATION Vol.8 No.2

Objective Benzodiazepines are from the most common drugs which are used for treatment of anxiety disorders. There are other drugs with antianxiety properties including antihistamines such as hydroxyzine, too. Body of evidence show that co-administration of two drugs which act through different mechanisms, makes the dose of each drug to be reduced, while preserving the desired effect with less adverse drug reactions. The aim of this study was to see whether co-administration of subeffective antianxiety doses of diazepam and hydroxyzine has any antianxiety effect in elevated zero-maze (EZM) in mice. Methods To find the highest subeffective dose of each drug, different doses of hydroxyzine from 1.5 to 24 mg/kg and diazepam in doses of 0.25, 0.5 and 1 mg/kg were injected to male mice. Thirty minutes later, the animals were placed on EZM and various parameters of an-xiety were recorded by a camera to assess later. After determination of subeffective antianxiety dose of the drugs, co-administration of hydroxyzine and diazepam was done and the anxiety parameters were measured. Results In co-administration of 0.25 mg/kg of diazepam and 12 mg/kg hydroxyzine, as subeffective antianxiety doses of either drug, there were not any significant differences in main anxiety parameters, i.e., time spent in open areas and open area entries compared to control group. Hence, no anxiolytic effect was seen. Conclusion It seems that subeffective doses of diazepam and hydroxyzine may not have any facilitating or synergistic effect on each other in antianxiety responses in mice. Objective Benzodiazepines are from the most common drugs which are used for treatment of anxiety disorders. There are other drugs with antianxiety properties including antihistamines such as hydroxyzine, too. Body of evidence show that co-administration of two drugs which act through different mechanisms, makes the dose of each drug to be reduced, while preserving the desired effect with less adverse drug reactions. The aim of this study was to see whether co-administration of subeffective antianxiety doses of diazepam and hydroxyzine has any antianxiety effect in elevated zero-maze (EZM) in mice. Methods To find the highest subeffective dose of each drug, different doses of hydroxyzine from 1.5 to 24 mg/kg and diazepam in doses of 0.25, 0.5 and 1 mg/kg were injected to male mice. Thirty minutes later, the animals were placed on EZM and various parameters of an-xiety were recorded by a camera to assess later. After determination of subeffective antianxiety dose of the drugs, co-administration of hydroxyzine and diazepam was done and the anxiety parameters were measured. Results In co-administration of 0.25 mg/kg of diazepam and 12 mg/kg hydroxyzine, as subeffective antianxiety doses of either drug, there were not any significant differences in main anxiety parameters, i.e., time spent in open areas and open area entries compared to control group. Hence, no anxiolytic effect was seen. Conclusion It seems that subeffective doses of diazepam and hydroxyzine may not have any facilitating or synergistic effect on each other in antianxiety responses in mice.

Cone-beam computed tomographic comparison of chin symphysis bone particles and allograft versus iliac crest bone graft alone for reconstruction of alveolar bone defects in cleft patients

Bijan Movahedian Attar,Parisa Soltani,Davood Davari,Mojdeh Mehdizadeh 대한구강악안면외과학회 2022 대한구강악안면외과학회지 Vol.48 No.2

Objectives: The aim of this study was to compare morbidities and duration of surgery, as well as bone formation in alveolar defects reconstructed with symphysis bone combined with allograft and iliac crest bone graft in patients with cleft palate. Patients and Methods: This randomized clinical trial was performed with 22 patients with unilateral alveolar cleft with a follow-up period of 12 months. In 12 patients, alveolar defects were reconstructed with chin bone graft plus allograft (Group A), while for the other 10 patients, iliac bone crest was used as donor site (Group B). Duration of surgery as well as occurrence of morbidities and complications were recorded. In addition, cone-beam computed tomographic (CBCT) scans were performed before surgery and 12 months after surgical procedures in order to compare bone forma-tion between the two groups. Results: Postoperative CBCT demonstrated a mean bone fill percentage of 76.9% of the alveolar defect in Group A, compared with 77.0% in Group B. Paresthesia in the lower lip or chin did not occur in any patients of Group A. The mean duration of the surgical process was significantly shorter for Group A (40 minutes vs 76 minutes, P<0.001). In addition, patients in Group A regained normal gait faster than patients in Group B (1 day vs 9.5 days). Conclusion: Mandibular symphysis bone graft in combination with allograft results in favorable outcomes in patients with unilateral alveolar clefts.

Effects of Constrained Groove Pressing (CGP) on the plane stress fracture toughness of pure copper

Bijan Mohammadi,Marzieh Tavoli,Faramarz Djavanroodi 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.5

Among severe plastic deformation methods, groove pressing is one of the prominent techniques for producing ultra-fine grained sheet materials. This process consists of imposing repetitive severe plastic deformation on the plate or sheet metals through alternate pressing. In the current study, a 2 mm pure Cu sheet has been subjected to repetitive shear deformation up to two passes. Hardness and tensile yield and ultimate stress were obtained after groove pressing. Fracture toughness tests have been performed and compared for three conditions of sheet material namely as received (initial annealed state), after one and two passes of groove pressing. Results of experiments indicate that a decrease in the values of fracture toughness attains as the number of constrained groove pressing (CGP) passes increase.