Advances in the design of macroporous polymer scaffolds for potential applications in dentistry

Bencherif, Sidi A.,Braschler, Thomas M.,Renaud, Philippe Korean Academy of Periodontology 2013 Journal of Periodontal & Implant Science Vol.43 No.6

A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications.

Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross‑Correlation Assessment

Y. A. Bencherif,A. Mekhaldi,J. Lobry,M. Olivier,M. Poorteman,L. Bonnaud 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1

The aim of this study is to highlight the joint evolution of the chemical, morphological, thermal and dielectric behaviors upon the UV weathering of an industrial ethylene-propylene-diene monomer (EPDM) rubber. This latter is used as a housing of composite high voltage insulators which are installed in the Algerian desert. This material was submitted to photochemical aging by irradiating UVA rays (λ=340 nm) at a temperature of 45 °C in order to simulate the witnessed site conditions. It was shown that the degradation process leading to the formation of oxygenated species and the depolymerization of the material are responsible of the coupling which may appear between the realized measurements. Using Kendall rank correlation analysis, joint evolution models were established. Those models introduce a novel assessment approach of the chemical and morphological status of the aged rubber using electrical and dielectric measurements.

Advances in the design of macroporous polymer scaffolds for potential applications in dentistry

Sidi A. Bencherif,Thomas M. Braschler,Philippe Renaud 대한치주과학회 2013 Journal of Periodontal & Implant Science Vol.43 No.6

A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size,thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissueengineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications. A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size,thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissueengineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications.

RF/analog Performance Assessment of High Frequency, Low Power In 0.3 Al 0.7As/InAs/InSb/In0.3 Al0.7 As HEMT Under High Temperature Effect

M. Khaouani,H. Bencherif,A. Hamdoune,A. Belarbi,Z. Kourdi 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.4

In this paper, we performed a Pseudo-morphic High Electron Mobility Transistors (pHEMT) In0.3 Al0.7 As/InAs/InSb/In0.3 Al0.7 using Silvaco-TCAD. RF and analog electrical characteristics are assessed under high temperature eff ect. The impact of the temperature is evaluated referring to a device at room temperature. In particular, the threshold voltage ( V th ), transconductance ( g m ), and I on / I off ratio are calculated in the temperature range of 300 K to 700 K. The primary device exhibits a drain current of 950 mA, a threshold voltage of −1.75 V, a high value of transconductance g m of 650 mS/mm, I on / I off ratio of 1 × 10 6 , a transition frequency ( f t ) of 790 GHz, and a maximum frequency ( f max ) of 1.4 THZ. The achieved results show that increasing temperature act to decrease current, reduce g m , and I on / I off ratio. In more detail high temperature causes a phonon scattering mechanism happening that determine in turn a reduced drain current and shift positively the threshold voltage resulting in hindering the device DC/AC capability.

Boosted Perovskite Photodetector Performance Using Graphene as Transparent Electrode

M. Khaouani,H. Bencherif,A. Meddour 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.2

In this paper, a new perovskite photodetector based on Graphene/reduced Graphene oxide/Perovskite material system has been investigated. A rigorous study through design of high speed and high sensitivity photodetector has been conducted to achieve an optimum device performance. The proposed photodetector was studied using 3D Atlas Silvaco simulator with regard to dark current, energy band diagram, electric fi eld profi le, photo to dark current ratio (PDCR), responsivity, sensitivity and detectivity. Our fi ndings demonstrate the outstanding ability of the proposed Graphene electrode scheme to reduce the undesirable shadowing eff ect and enhance the collection mechanism. Besides, reduced graphene oxide interlayer with high conductivity plays a crucial role for high effi cient charge transportation. The proposed design displays 10 times photocurrent improvement when compared to the conventional design Au/TiO 2 /Perovskite photodetector. The proposed device displays a high value of responsivity of 340 A/W, a 100 GHz bandwidth with 10 μs transient response, and signifi cant PDCR of 646.4, high detectivity of 2.61 × 10 13 (Jones) and high sensitivity of 6.46 × 10 4 . In addition, the proposed photodetector shows ruggedness under high temperature condition. This modeling strategy is able to direct other researchers in the design and development of effi cient perovskite optoelectronic devices.

Brain mu-opioid receptor binding: relationship to relapse to cocaine use after monitored abstinence.

Gorelick, David A,Kim, Yu Kyeong,Bencherif, Badreddine,Boyd, Susan J,Nelson, Richard,Copersino, Marc L,Dannals, Robert F,Frost, J James Springer-Verlag 2008 Psychophamacology Vol.200 No.4

<P>Cocaine users have increased regional brain mu-opioid receptor (mOR) binding which correlates with cocaine craving. The relationship of mOR binding to relapse is unknown.</P>

Performance Evaluation and Comparison of Monolithic and Mechanically Stacked Dual Tandem InGaP/GaAs Heterojunction on Ge Cell: A TCAD Study

O. Terghini,L. Dehimi,A. M. Mefteh,H. Bencherif 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.4

The photovoltaic characteristics of a mechanically and monolithic stacked tandem solar cell of the heterojunction InGaP/GaAs and Ge sub cells, were numerically simulated under 1-sun air mass 1.5 global spectrum (AM1.5G) at ambient temperature (300 K) using the two-dimensional device simulator Silvaco–Atlas. Our tandem structure consists of a thin upper cell with heterojunction of indium and gallium phosphide on gallium arsenide ( In 0.49 Ga 0.51 P/GaAs ), on a relatively thick germanium ( Ge ) substrate which acts as a lower cell in order to obtain good performances of such a structure. We studied both cells, stacked mechanically (four terminal:4T) and monolithic (two terminal:2T) using Silvaco ATLAS Virtual Wafer FabricationTool. First, we have simulated the single InGaP/GaAs and Ge solar cells with fi xed thicknesses at 1.4 μm and 210 μm respectively. They presented a conversion effi ciencies ( ) of 30.32% and 10.96% respectively. The effi ciency of mechanically stacked tandem solar is 30.96% and short current density of 26.16 mA/cm 2 which is limited by the lower short current density of both sub-cells. Using the method of current matching, by varying the base thicknesses of the InGaP/GaAs top and Ge bottom sub-cells, the numerical simulation results presented a matched maximum current J sc value of 29.12 mA/cm 2 obtained at base thicknesses of 0.605 and 209.9 μ m for the InGaP/GaAs top and Ge bottom sub-cells respectively, leading to a high power conversion effi ciency ( ) of the mechanically stacked sub cells of 34.77%, the open-circuit voltage and the fi ll factor are 1.329 V and 88.96%, respectively. Next, the sub-cells were interconnected with tunnel junctions (TJs), p - GaAs/n - GaAs to allow carrier transport, the results of the monolithic stacked sub-cells are converged with results of themechanically stacked sub-cells, and are represented in the following results of the tandem cell: power conversion effi ciency ( ) of 32.96%, the open-circuit voltage of 1.343 V, the short current of 29.19 mA/cm 2 and the fi ll factor of 84.05%.