127 research outputs found
Development Cabinet Formalized
Alzheimer's disease (AD) is a kind of brain disease that arises due to the aggregation and fibrillation of amyloid β-peptides (Aβ). The peptide Aβ17-42 forms U-shape protofilaments of amyloid mature fibrils by cross-β strands, detected in brain cells of individuals with AD. Targeting the structure of Aβ17-42 and destabilizing its β-strands by natural compounds could be effective in the treatment of AD patients. Therefore, the interaction features of monomeric U-shape Aβ17-42 with natural flavonoids including myricetin, morin and flavone at different mole ratios were comprehensively studied to recognize the mechanism of Aβ monomer instability using molecular dynamics (MD) simulations. We found that all flavonoids have tendency to interact and destabilize Aβ peptide structure with mole ratio-dependent effects. The interaction free energies of myricetin (with 6 OHs) and morin (with 5 OHs) were more negative compared to flavone, although the total binding energies of all flavonoids are favorable and negative. Myricetin, morin and flavone penetrated into the core of the Aβ17-42 and formed self-clusters of Aβ17-42-flavonoid complexes. Analysis of Aβ17-42-flavonoids interactions identified that the hydrophobic interactions related to SASA-dependent energy are weak in all complexes. However, the intermolecular H-bonds are a main binding factor for shifting U-shape rod-like state of Aβ17-42 to globular-like disordered state. Myricetin and morin polyphenols form H-bonds with both peptide's carbonyl and amine groups whereas flavone makes H-bonds only with amine substitution. As a result, polyphenols are more efficient in destabilizing β-sheet structures of peptide. Accordingly, the natural polyphenolic flavonoids are useful in forming stable Aβ17-42-flavonoid clusters to inhibit Aβ17-42 aggregation and these compounds could be an effective candidate for therapeutically targeting U-shape protofilaments' monomer in amyloid mature fibrils
Application of Chitosan Hydrogels in Traumatic Spinal Cord Injury; A Therapeutic Approach Based on the Anti-inflammatory and Antioxidant Properties of Selenium Nanoparticles
Abstract
Purpose: The pathophysiological progression of traumatic spinal cord injury (SCI) includes primary and secondary injury. Secondary injury causes the destruction of the spinal cord tissue and neurological disorders. After primary mechanical damage, inflammation is the most important factor inducing astrogliosis and scar formation. The activation of inflammatory cells in the area of damage causes the production of free radicals, all of which damage cell membranes. A significant level of oxygen free radical production is involved in the pathology of SCI; Therefore, limiting secondary damage is very important in the clinical treatment of acute traumatic spinal cord injury.
Materials and Methods: In this review article, the articles indexed in various databases were used. The collection of articles was evaluated without time constraints using keywords inducing traumatic spinal cord injury (SCI), inflammation, oxidative stress, chitosan, selenium nanoparticles.
Results: Inflammation and oxygen free radicals play a key role in secondary damage after SCI. Therefore, as a new therapeutic approach, the use of - hydrogels based on chitosan has been considered in SCI. The biocompatibility and biological properties of chitosan have made it considered as a suitable material for nerve regeneration.
Conclusion: The use of reactive oxygen species scavengers, including metal nanoparticles, can control inflammation and oxidative stress in spinal cord injuries. Selenium nanoparticles treatment may reduce secondary damage in SCI by using its anti-inflammatory and antioxidant properties. Therefore, the use of selenium nanoparticles in the chitosan hydrogel bed can control the degeneration and functional improvement of the nerve tissue of the spinal cord
Intracellular ROS Protection Efficiency and Free Radical-Scavenging Activity of Curcumin
Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin showed a powerful capacity for scavenging intracellular smaller oxidative molecules such as H2O2, HO•, ROO•. Cell viability and ROS assays demonstrated that curcumin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and lethal effects of cumene hydroperoxide. Curcumin also showed good electron-transfer capability, with greater activity than trolox in aqueous solution. Curcumin can readily transfer electron or easily donate H-atom from two phenolic sites to scavenge free radicals. The excellent electron transfer capability of curcumin is because of its unique structure and different functional groups, including a β-diketone and several π electrons that have the capacity to conjugate between two phenyl rings. Therfore, since curcumin is inherently a lipophilic compound, because of its superb intracellular ROS scavenging activity, it can be used as an effective antioxidant for ROS protection within the polar cytoplasm
Customer Experience of Electronic Services in Information Technology Organizations Based on Digital Developments
Purpose: Customer experience management is one of the most important activities for managers who are trying to grow and develop to achieve a favorable competitive position. The purpose of this study is to evaluate the dimensions of customer experience in the process of using electronic services in information technology organizations (Hamrah-e-Aval).
Method: The method of this study is quantitative. In this regard, a questionnaire was designed and distributed among the statistical population by the available sampling method. The data analysis method is structural equation modeling and the software used is SPSS25 and SMART PLS 3.0.
Findings: Findings show that awareness is the first step in managing customer experience. The second step deals with the active organizational actor. The third step, or evaluation, is based on service characteristics and service arrangements. The fourth step (buying decision). Purchasing and the resulting experience is the fifth step. Step 6 (Use) is a function of activities including delivery and use. The seventh step is to repeat the purchase, complain or not react to the use of the product (service). Finally, the customer's secondary response is the last step of the customer experience model.
Conclusion: Based on the findings of the present study, information interface can play a decisive role in shaping customer experiences. Therefore, it is suggested that in the active businesses in the information and communication technology industry, by studying the media and customer information tools, the most optimal and effective tools should be selected and used
Validation of the Persian Translation of the Swallowing Disturbance Questionnaire in Parkinson’s Disease Patients
Dysphagia, as a common finding in Parkinson’s disease (PD) patients, was estimated to be present in 80–95% of this population during different stages of the disease. The Swallowing Disturbance Questionnaire (SDQ) was created as a self-rated dysphagia screening tool in PD. According to the guidelines for cross-cultural adaptation, Persian version of this questionnaire (SDQ-P) was developed. 59 Persian patients (39 men and 20 women) participated in the study. They responded to the SDQ-P and underwent videofluoroscopic swallowing study (VFSS). Aspiration during VFSS was compared with questionnaire results for each individual. Cronbach’s alpha coefficient for the questionnaire was 0.86 and based on SDQ-P 15 patients (25.4%) were dysphagic, while 10 patients (16.9%) showed aspiration during VFSS. SDQ-P sensitivity and specificity in predicting aspiration were 96.7 and 91.2%; therefore, the SDQ-P could be a prognostic tool for aspiration. The positive predictive value (PPV), the negative predictive value (NPV), and the pre- and posttest probabilities of aspiration were 0.67, 1, 16.9%, and 66.7%, respectively. In summary, this study demonstrated the reliability and also the feasibility of SDQ-P for screening of aspiration in Iranian patients with PD. Further evaluation of SDQ-P in larger subject population would be suggested
Network-Based and Machine-Learning Approaches Identify Diagnostic and Prognostic Models for EMT-Type Gastric Tumors
The microsatellite stable/epithelial-mesenchymal transition (MSS/EMT) subtype of gastric cancer represents a highly aggressive class of tumors associated with low rates of survival and considerably high probabilities of recurrence. In the era of precision medicine, the accurate and prompt diagnosis of tumors of this subtype is of vital importance. In this study, we used Weighted Gene Co-expression Network Analysis (WGCNA) to identify a differentially expressed co-expression module of mRNAs in EMT-type gastric tumors. Using network analysis and linear discriminant analysis, we identified mRNA motifs and microRNA-based models with strong prognostic and diagnostic relevance: three models comprised of (i) the microRNAs miR-199a-5p and miR-141-3p, (ii) EVC/EVC2/GLI3, and (iii) PDE2A/GUCY1A1/GUCY1B1 gene expression profiles distinguish EMT-type tumors from other gastric tumors with high accuracy (Area Under the Receiver Operating Characteristic Curve (AUC) = 0.995, AUC = 0.9742, and AUC = 0.9717; respectively). Additionally, the DMD/ITGA1/CAV1 motif was identified as the top motif with consistent relevance to prognosis (hazard ratio > 3). Molecular functions of the members of the identified models highlight the central roles of MAPK, Hh, and cGMP/cAMP signaling in the pathology of the EMT subtype of gastric cancer and underscore their potential utility in precision therapeutic approaches
Development of a new sequential block finding strategy for detection of conserved sequences in riboswitches
Introduction: Some non-coding RNAs have an important role in the regulation of gene expression and consequently cellular function. Riboswitches are examples of these regulatory RNAs. Riboswitches are classified into various families according to sequential and structural similarities. Methods: In this study, a block finder algorithm for identification of frequently appearing sequential blocks in five families of riboswitches from Rfam 12.0 database, without the use of alignment methods, was developed. Results: The developed program identified 21 frequently appearing blocks in five families of riboswitches. Conclusion: Comparison of the results of the proposed algorithm with those of sequential alignment methods revealed that our method can recognize most of the patterns present in conserved areas of individual riboswitch families and determine them as specific blocks, implying potential of the developed program as a platform for further studies and developments
Preparation and Administration of a Controlled-Release Delivery System of Chitosan Hydrogel loaded with Methadone and Piroxicam in Experimental Defect of Tibial in Rats; Histopathological Evaluation
Purpose: In this study, a controlled release drug delivery system loaded with piroxicam and methadone was synthesized and used subcutaneously in rat with experimental tibial defect and healing were assessed histopathologically.
Materials and Methods: For this purpose 100 adult female rats were were randomly divided into five equal groups; group control, chitosan group, piroxicam group, methadone group, and piroxicam-methadone group. The morphological structure of the synthesized drug systems was studied by scanning electron microscope. In addition, the structure of the hydrogels was investigated by fourier transform infrared spectroscopy and while releasing the hydrogels gelation time, the release of piroxicam and methadone from the hydrogels were evaluated in vitro.
Results: Histological results of the 3rd day of the study showed the lowest extent and severity of inflammation in the chitosan, piroxicam, and piroxicam-methadone groups, while on the 7th day, tissue inflammation and the extent of bleeding was lower in the piroxicam, methadone, and piroxicam-methadone groups than in the other groups. Evaluation of new bone formation on day 21 showed that the chitosan, piroxicam, and methadone groups had better repair than the other groups.
Conclusion: It seems that in the control group that did not receive any treatment intervention, following the experimental bone defect, the highest inflammatory response was observed in histological examination and finally the weakest bone repair. On the other hand, the presence of piroxicam, methadone and chitosan in the piroxicam-methadone group (all of which have anti-inflammatory effects) also seems to have a negative effect on repair
Development and Characterization of a Functional Smart PVA/NC/PCL Nano-biocomposite Using E. Coli Phage: Insights into Physicochemical Properties and Antimicrobial Activity
Food packaging plays a critical role in preserving the freshness and quality of foods while preventing microbial spoilage. Advances in this field have led to the development of intelligent and active packaging systems incorporating nanotechnology. Among these, electrospinning has gained attention for producing nanofibrous materials with high surface-to-volume ratios, enabling the efficient loading of active agents.In response to the growing concern over antibiotic-resistant bacteria, this study investigates the use of bacteriophages as an alternative antimicrobial agent. Lytic bacteriophages targeting Escherichia coli were isolated from Caspian seawater and immobilized onto electrospun nanofibers composed of polyvinyl alcohol (PVA), polycaprolactone (PCL), and bacterial nanocellulose (BNC). SEM confirmed successful phage immobilization, while TEM revealed their classification within the Siphoviridae and Podoviridae families.The addition of PCL to PVA enhanced the fibers' mechanical strength, reduced defects, and improved water resistance. Incorporating BNC further strengthened the nanofiber structure and enhanced its matrix properties. Antimicrobial testing using the disc diffusion method revealed an inhibition halo of 13 mm, exceeding that of the antibiotic ampicillin. Notably, the functionalized nanofibers retained antimicrobial efficacy for up to one month, with stable phage viability at 24°C, 4°C, and -20°C.These findings demonstrate the potential of electrospun nanofibers functionalized with bacteriophages as a sustainable solution for combating bacterial contamination in food packaging, contributing to enhanced food safety and extended shelf life
Spectroscopic, thermodynamic and molecular docking studies of bovine serum albumin interaction with ascorbyl palmitate food additive
Introduction: Ascorbyl palmitate (AP) is an example of natural secondary food antioxidant, which has been used for oxidative rancidity prevention in food industry. In this study, the interaction of AP with bovine serum albumin (BSA) was investigated. Methods: The mechanism of BSA interaction with AP was investigated using spectroscopic methods (UV-Vis, fluorescence). The thermodynamic parameters including enthalpy change (ΔH), entropy change (ΔS), and Gibb’s free energy (ΔG) were calculated using Van’t Hoff equation at different temperatures. Results: The experimental results showed that UV-Vis absorption spectra of BSA decreased upon increasing AP concentration, indicating that the AP can bind to BSA. Formation of the AP-BSA complex was approved by quenching of fluorescence and the quenching mechanism was found to be resultant from dynamic procedure. The positive values of both ΔH and ΔS showed that hydrophobic forces were the major binding forces. The negative value of ΔG demonstrated that AP interacts with BSA spontaneously. Molecular docking results confirmed that AP binds to BSA through hydrophobic forces. Conclusion: The attained results showed that AP can bind to BSA and effectively distributed into the bloodstream
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