In vitro assessment of cytotoxicity of giomer on human gingival fibroblasts

Root coverage on restored root surfaces has been considered as a challenging issue. The evaluation of cytotoxic effects of restorative materials is a fundamental requirement for sustaining the cell attachment and the clinical success of root coverage. The aim of the present study was to compare the human gingival fibroblast cytotoxicity of the recently introduced giomer composite (GC) with resin ionomer (RI) restorative material. Discs (6x2 mm) of GC and RI restorative materials were prepared using sterile Teflon mold. Extracts from the materials were incubated to cell culture medium for 24, 48 and 72 h. Human gingival fibroblasts (HGF) were exposed to the extracts of the materials while the un-incubated media served as the control group. The cytotoxicity of the materials were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In order to compare the mean values of the measured parameters a Kruskal-Walis test was carried out. MTT assay indicated that human gingival fibroblasts proliferated well in the presence of GC extract. The proliferation rate was higher in cells incubated with GC compared to RI extracts but the differences were not statistically significant (p= 0.09). This in vitro study indicated that GC is a non-toxic material for HGF. However, further studies are needed to assess the other biologic and clinical behavior of this material prior to it being considered as a potentially suitable restorative material to restore the carious root lesions candidated to root coverage procedures

A hybrid approach to achieve organizational agility: An empirical study of a food company

Purpose: In today’s intense global competition, agility is advocated as a fundamental characteristic for business survival and competitiveness. The purpose of this paper is to propose a practical methodology to achieve and enhance organizational agility based on strategic objectives. Design/methodology/approach: In the first step, a set of key performance indicators (KPIs) of the organization being studied are recognized and classified under the perspectives of balanced scorecard (BSC). Critical success factors are then identified by ranking the KPIs according to their importance in achieving organizational strategic objectives using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). In the second step, three houses of quality (HOQs) are constructed sequentially to identify and rank the main agile attributes, agile enablers, and improvement paths. In addition, in order to translate linguistics judgments of practitioners into numerical values in building HOQs, fuzzy logic is employed. Findings: The capability of the proposed methodology is demonstrated by applying it to a case of a multi-national food company in Iran. Through the application, the company could find the most suitable improvement paths to improve its organizational agility. Research limitations/implications: A limited number of KPIs were chosen due to computational and visual constraints related to HOQs. Another limitation, similar to other agility studies, which facilitate decision making among agility metrics, was that the metrics were more industry-specific and less inclusive. Practical implications: A strong practical advantage for the application of the methodology over directly choosing agility metrics without linking them is that through the methodology, the right metrics were selected that match organization’s core values and marketing objectives. While metrics may ostensibly seem unrelated or inappropriate, they actually contributed to the right areas where there were gaps between the current and desired level of agility. It would otherwise be impossible to choose the right metrics without a structured methodology. Originality/value: This paper proposes a novel methodology for achieving organizational agility. By utilizing and linking several tools such as BSC, fuzzy TOPSIS, and quality function deployment (QFD), the proposed approach enables organizations to identify the most appropriate agile attributes, agile enablers, and subsequently agile improvement paths

In vitro assessment of cytotoxicity of giomer on human gingival fibroblasts

Root coverage on restored root surfaces has been considered as a challenging issue. The evaluation of cytotoxic effects of restorative materials is a fundamental requirement for sustaining the cellattachment and the clinical success of root coverage. The aim of the present study was to compare the human gingival fibroblast cytotoxicity of the recently introduced giomer composite (GC) with resinionomer (RI) restorative material. Discs (6×2 mm) of GC and RI restorative materials were prepared using sterile Teflon mold. Extracts from the materials were incubated to cell culture medium for 24, 48and 72 h. Human gingival fibroblasts (HGF) were exposed to the extracts of the materials while the unincubated media served as the control group. The cytotoxicity of the materials were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In order to compare the mean values of the measured parameters a Kruskal-Walis test was carried out. MTT assay indicated that human gingival fibroblasts proliferated well in the presence of GC extract. The proliferation rate washigher in cells incubated with GC compared to RI extracts but the differences were not statistically significant (p= 0.09). This in vitro study indicated that GC is a non-toxic material for HGF. However, further studies are needed to assess the other biologic and clinical behavior of this material prior to it being considered as a potentially suitable restorative material to restore the carious root lesions candidated to root coverage procedures

Fuzzy Based PC-PUSH in CR-MANETs

In cognitive radio (CR), the secondary user (SU) needs to hand off its ongoing communication to an idle channel in order to avoid interference to the primary user (PU). Spectrum hand off issue becomes challenging in CR mobile ad hoc networks (CR-MANETs) because of the uncertainty in spectrum availability, broad range of spectrum bands and lack of central entity. The purpose of this study is to design a unified spectrum handoff (USH) scheme for CR-MANETs that considers the spectrum heterogeneity and its availability over time and space. A local flow hand off is performed when spectrum hand off cannot be carried out due to the SUs mobility. To improve further USH, preemptive unified spectrum handoff (PUSH) algorithm is proposed in which two different preemptive hand off threshold regions are defined. The PUSH algorithm also predicts the cognitive link availability considering the PU interference boundary. Although the PUSH scheme improves the hand off performance, the number of spectrum hand offs due to the PU activity should be reduced in this scheme. Therefore, the PC-PUSH (Power Controller-PUSH) scheme is proposed in which the fuzzy logic is used to improve the PUSH in terms of the number of spectrum handoffs because of the PU activity. The PC-PUSH decreases the interference to the PUs, while reducing the number of spectrum handoffs. The results show that the proposed scheme improves the link maintenance probability, decreases the hand off delay, and reduces the number of spectrum handoffs

Characterization of End-to-end Path Selection for Cognitive Radio Wireless Mesh Networks

Abstract: The Cognitive Radio (CR) can delivers the environment to Secondary Users (SUs) of Wireless Mesh Network (WMN) to utilize unused spectrum of Primary Users (PUs) opportunistically. The CR can improve the spectrum usage of the WMN. However, this rises the some additional complexities for the SUs such as spectrum heterogeneity, unpredictable PU activity and interference constraints. In this paper an analytical model has been developed to analyse these complexities for each SU node and link characteristics for end-to-end optimal Path and channel assignment. Numerical results show that the analytical model is an effective tool to investigate the effects of the PU activities and channel heterogeneity on the network performance

Enhancing Controlled Environment Agriculture in Desert Ecosystems with AC/DC Hybrid Solar Technology

Received: 29 March 2023. Accepted: 26 May 2023.Controlled Environment Agriculture (CEA) plays a crucial role in promoting sustainable farming practices within the challenging climate of the Arabian Peninsula. Traditional CEAs, however, are confronted with excessive water and electricity consumption due to the region's elevated temperatures and humidity levels. To address these challenges, an innovative project was carried out at the Al Dhaid Research Station, United Arab Emirates, integrating solar-powered cooling and irrigation, closed hydroponic systems, net-house structures, root zone cooling, and ultra-low-energy drippers. The study employed a cooled greenhouse alongside two net houses, one of which was equipped with a solar-powered cooling and irrigation system. Cucumber crops were cultivated within each structure, demonstrating that the combined technologies could prolong production periods despite increasing temperatures, while simultaneously reducing energy consumption by 95% and water usage by 80%, without compromising crop yield. The findings of this study suggest that the implementation of this novel approach holds significant potential for boosting crop productivity and water efficiency in desert agriculture systems.This publication showcases a collaborative effort between ICARDA and NARS in the countries of the Arabian Peninsula. The contributions and efforts of the NARS, particularly in the UAE where this study was conducted, are highly acknowledged and appreciated. We extend our heartfelt gratitude to the Arab Fund for Economic and Social Development (AFESD) and The Kuwait Fund for Arab Economic Development (KFAED) for their invaluable financial support to ICARDA-APRP. Their generous contributions have played a crucial role in facilitating the research and implementation of this project

Multilayer diffusion-based molecular communication

Diffusion-based molecular communication (DBMC) has emerged as a promising communication option, particularly for biomedical and healthcare applications. Although, numerous studies have been conducted to evaluate and analyse DBMC system, investigation on DBMC through multilayer channels has had less attention. In this paper, a closed-form expression is derived for the mean molecular concentration over an n-layer channel. An averaged diffusion coefficient for thin, dissimilar and multilayer propagation channels is determined through the addition of a diffusion resistance for each medium analogously to the sum of series resistors in circuit theory. The channel characteristics such as impulse response, time delay and attenuation are analytically obtained using amplitude detection technique. The effects of layer thickness and the distance between a transmitter nanomachine and a receiver nanomachine on the channel time delay and channel attenuation under the pulse modulation scheme are evaluated and discussed. The results show that increasing the diffusion coefficient leads to time delay decrements; however, the channel attenuation remains unchanged. Moreover, lengthening the transmission distance increases the time delay and decreases the channel attenuation. Copyright © 2015 John Wiley & Sons, Ltd

Investigation of Frost Tolerance of Flower in Two Iranian Cornelian Cherry Clones

In many areas, low temperature is an important environmental limiting factor in production and distribution of horticultural trees and plants. This study was conducted to study the frost tolerance of main local clones of cornelian cherry in Tarom Sofla region, Qazvin, Iran. Cold treatments at 5 levels (+4, +2, 0, -2 and -4 ˚C) at two cooling periods (3 and 5 hours) were arranged as a factorial experiment, based on completely randomized design with 4 replications, at flowering stage of Golabie Siah (black pear) and Paeizi (autumn) clones in 2009-2010. For each treatment, the electrical conductivity (EC) and acidity (pH) were measured just after shaking (t=0), every 3 hours in the first 24 hours, and once daily in the 2nd to 8th day. After a week, the samples were autoclaved at 105˚C for 4 minutes and the changes were recorded. Results showed that the range of EC in flower was 92.2-846.2 µS/cm, and the range of pH varied from 6.4 to 7.7. Based on the results, the effect of frost intensity on EC changes was ascending, and on pH was slowly ascending and sometimes fixed. The highest value of EC due to destruction of tissues, as an index of frost damage of the flower, was obtained at +4 ˚C. Therefore, tolerance range of cornelian cherry flower has been estimated to be more than +4 ˚C

Handoff management in cognitive radio networks: concepts, protocols, metrics and challenges

In Cognitive Radio (CR) networks, Secondary Users (SUs) use the unused spectrum bands. Once the band of the spectrum, which is occupied by the SU, is claimed by a Primary user (PU), the SU transfers its data transmission into another empty band of the spectrum. Changing the operation frequency is called spectrum handoff. During the spectrum handoff, the SUs transfer their ongoing calls to an unused spectrum band upon the presence of the PU. In this paper, we investigate a brief overview of spectrum mobility and handoff management in cognitive radio. The main concepts, protocols, and tools are also proposed in this literature. We also introduce the concept of integrated mobility and handoff management. In addition, we illustrate the most challenging and open issues of spectrum mobility and handoff management in CR networks