In the present work, ZnO·PbO·B2O3 glasses are prepared to be used as g-ray shielding materials. The attenuation properties of these glasses with different concentrations of PbO (20% - 70%) have been investig...In the present work, ZnO·PbO·B2O3 glasses are prepared to be used as g-ray shielding materials. The attenuation properties of these glasses with different concentrations of PbO (20% - 70%) have been investigated at photon energies 662, 1173, 1332 and 2614 keV. The optical absorption spectra of some glass samples have been measured from 200 to 1100 nm before and after g-ray irradiation. The analyses of these spectra have been interpreted and discussed.展开更多
Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug delivery.Herein,novel hollow bioactive glass nanospheres(HBGn)with large hollow cavity and large mes...Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug delivery.Herein,novel hollow bioactive glass nanospheres(HBGn)with large hollow cavity and large mesopores in their outer shells were synthesized by a simple and facile one-pot ultrasound assisted sol-gel method using PEG as the core soft-template.Interestingly,the produced HBGn exhibited large hollow cavity with ~43 nm in diameter and mesoporous shell of ~37 nm in thickness and 7 nm pore size along with nanosphere size around 117 nm.XPS confirmed the presence of Si and Ca elements at the surface of the HBGn outer shell.Notably,HBGn showed high protein loading capacity(~570 mg of Cyto c per 1 g of HBGn)in addition to controlled protein release over 5 d.HBGn also demonstrated a good in vitro capability of releasing calcium(Ca^(2+):170 ppm)and silicate(SiO_(4)^(4-):78 ppm)ions in an aqueous medium over 2 weeks under physiological-like conditions.Excellent in vitro growth of bone-like hydroxyapatite nanocrystals was exhibited by HBGn during the soaking in SBF.A possible underlying mechanism involving the formation of spherical aggregates(coils)of PEG was proposed for the formation process of HBGn.展开更多
The influence of adding Fe_(2)O_(3) at the expense of Na_(2)O in sodium lead borate glasses on the structural,physical and electrical properties have been investigated.Results obtained from Fourier transform infrared(...The influence of adding Fe_(2)O_(3) at the expense of Na_(2)O in sodium lead borate glasses on the structural,physical and electrical properties have been investigated.Results obtained from Fourier transform infrared(FTIR)spectra indicated that Fe_(2)O_(3) plays an important role in converting three coordinated boron atoms[BO_(3)]to four coordinated boron atoms[BO4].The physical properties such as density and molar volume helped to evaluate the compact structure of the prepared glass samples due to presence of[BO4]groups.The increase of Fe_(2)O_(3)/Na_(2)O replacements led to increasing the microhardness values and decreasing the thermal expansion coefficients of the studied glasses.The increase of Fe_(2)O_(3)/Na_(2)O replacements generally decreased the AC conductivity.That decrease might be due to converting of the three coordinated boron atoms[BO_(3)]to four coordinated boron atoms[BO_(4)].Dielectric constants of the samples might be an indication of the distortion in the coordinated boron atoms.The obtained experimental data indicated the internal structure of glass network and the change of the structure of the samples from three[BO_(3)]to four coordinated boron atoms[BO4].展开更多
About 8%of the imported iron oxide pellets burdens to Egypt are wasted.In this paper,broken pellets waste(BPW)is used as raw material for the preparation of hard magnetic glass ceramics(HMGC)as well as soft magnetic g...About 8%of the imported iron oxide pellets burdens to Egypt are wasted.In this paper,broken pellets waste(BPW)is used as raw material for the preparation of hard magnetic glass ceramics(HMGC)as well as soft magnetic glass ceramics(SMGC).About 54 wt%and 37 wt%of BPW are used to prepare SMGC and HMGC,respectively.Differential thermal analysis(DTA)reveals two broad exothermic peaks for HMGC at 591℃and 697℃,whereas one exothermic peak at 820℃is detected for SMGC.X-ray diffraction(XRD)shows the crystallization of hematite as the sol phase in BPW,and meanwhile,Zn-ferrite and Ba-hexaferrite are identified in SMGC and HMGC,respectively.Transmission electron microscopy(TEM)reveals the crystallization of nanosize particles of~20 nm for SMGC and~12 nm for HMGC.Vibrating scanning magnetometer(VSM)reveals an increase in saturation magnetization from~1 emu/g for BPW to~77 emu/g for SMGC and 21 emu/g for HMGC.展开更多
Processing biomaterials into porous scaffolds for bone tissueengineering is a critical and a key step in defining and controlling their physicochemical,mechanical,and biological properties.Biomaterials such as polymer...Processing biomaterials into porous scaffolds for bone tissueengineering is a critical and a key step in defining and controlling their physicochemical,mechanical,and biological properties.Biomaterials such as polymers are commonlyprocessed into porous scaffolds using conventional processing techniques,e.g.,saltleaching.However,these traditional techniques have shown unavoidable limitations andseveral shortcomings.For instance,tissue-engineered porous scaffolds with a complexthree-dimensional(3D)geometric architecture mimicking the complexity of theextracellular matrix of native tissues and with the ability to fit into irregular tissue defectscannot be produced using the conventional processing techniques.3D printing hasrecently emerged as an advanced processing technology that enables the processing ofbiomaterials into 3D porous scaffolds with highly complex architectures and tunableshapes to precisely fit into irregular and complex tissue defects.3D printing providescomputer-based layer-by-layer additive manufacturing processes of highly precise andcomplex 3D structures with well-defined porosity and controlled mechanical propertiesin a highly reproducible manner.Furthermore,3D printing technology provides anaccurate patient-specific tissue defect model and enables the fabrication of a patientspecifictissue-engineered porous scaffold with pre-customized properties.展开更多
Therapeutic options are quite limited in clinics for the successful repair of infected/degenerated tissues.Although the prevalent treatment is the complete removal of the whole infected tissue,this leads to a loss of ...Therapeutic options are quite limited in clinics for the successful repair of infected/degenerated tissues.Although the prevalent treatment is the complete removal of the whole infected tissue,this leads to a loss of tissue function and serious complications.Herein the dental pulp infection,as one of the most common dental problems,was selected as a clinically relevant case to regenerate using a multifunctional nanotherapeutic approach.For this,a mesoporous bioactive glass nano-delivery system incorporating silicate,calcium,and copper as well as loading epidermal growth factor(EGF)was designed to provide antibacterial/pro-angiogenic and osteo/odontogenic multiple therapeutic effects.Amine-functionalized Cu-doped bioactive glass nanospheres(Cu-BGn)were prepared to be 50–60 nm in size,mesoporous,positive-charged and bone-bioactive.The Cu-BGn could release bioactive ions(copper,calcium and silicate ions)with therapeutically-effective doses.The Cu-BGn treatment to human umbilical vein endothelial cells(HUVEC)led to significant enhancement of the migration,tubule formation and expression of angiogenic gene(e.g.vascular endothelial growth factor,VEGF).Furthermore,the EGF-loaded Cu-BGn(EGF@Cu-BGn)showed pro-angiogenic effects with antibacterial activity against E.faecalis,a pathogen commonly involved in the pulp infection.Of note,under the co-culture condition of HUVEC with E.faecalis,the secretion of VEGF was up-regulated.In addition,the osteo/odontogenic stimulation of the EGF@Cu-BGn was evidenced with human dental pulp stem cells.The local administration of the EGF@Cu-BGn in a rat molar tooth defect infected with E.faecalis revealed significant in vivo regenerative capacity,highlighting the nanotherapeutic uses of the multifunctional nanoparticles for regenerating infected/damaged hard tissues.展开更多
文摘In the present work, ZnO·PbO·B2O3 glasses are prepared to be used as g-ray shielding materials. The attenuation properties of these glasses with different concentrations of PbO (20% - 70%) have been investigated at photon energies 662, 1173, 1332 and 2614 keV. The optical absorption spectra of some glass samples have been measured from 200 to 1100 nm before and after g-ray irradiation. The analyses of these spectra have been interpreted and discussed.
文摘Hollow nanospheres exhibit unique properties and find a wide interest in several potential applications such as drug delivery.Herein,novel hollow bioactive glass nanospheres(HBGn)with large hollow cavity and large mesopores in their outer shells were synthesized by a simple and facile one-pot ultrasound assisted sol-gel method using PEG as the core soft-template.Interestingly,the produced HBGn exhibited large hollow cavity with ~43 nm in diameter and mesoporous shell of ~37 nm in thickness and 7 nm pore size along with nanosphere size around 117 nm.XPS confirmed the presence of Si and Ca elements at the surface of the HBGn outer shell.Notably,HBGn showed high protein loading capacity(~570 mg of Cyto c per 1 g of HBGn)in addition to controlled protein release over 5 d.HBGn also demonstrated a good in vitro capability of releasing calcium(Ca^(2+):170 ppm)and silicate(SiO_(4)^(4-):78 ppm)ions in an aqueous medium over 2 weeks under physiological-like conditions.Excellent in vitro growth of bone-like hydroxyapatite nanocrystals was exhibited by HBGn during the soaking in SBF.A possible underlying mechanism involving the formation of spherical aggregates(coils)of PEG was proposed for the formation process of HBGn.
文摘The influence of adding Fe_(2)O_(3) at the expense of Na_(2)O in sodium lead borate glasses on the structural,physical and electrical properties have been investigated.Results obtained from Fourier transform infrared(FTIR)spectra indicated that Fe_(2)O_(3) plays an important role in converting three coordinated boron atoms[BO_(3)]to four coordinated boron atoms[BO4].The physical properties such as density and molar volume helped to evaluate the compact structure of the prepared glass samples due to presence of[BO4]groups.The increase of Fe_(2)O_(3)/Na_(2)O replacements led to increasing the microhardness values and decreasing the thermal expansion coefficients of the studied glasses.The increase of Fe_(2)O_(3)/Na_(2)O replacements generally decreased the AC conductivity.That decrease might be due to converting of the three coordinated boron atoms[BO_(3)]to four coordinated boron atoms[BO_(4)].Dielectric constants of the samples might be an indication of the distortion in the coordinated boron atoms.The obtained experimental data indicated the internal structure of glass network and the change of the structure of the samples from three[BO_(3)]to four coordinated boron atoms[BO4].
文摘About 8%of the imported iron oxide pellets burdens to Egypt are wasted.In this paper,broken pellets waste(BPW)is used as raw material for the preparation of hard magnetic glass ceramics(HMGC)as well as soft magnetic glass ceramics(SMGC).About 54 wt%and 37 wt%of BPW are used to prepare SMGC and HMGC,respectively.Differential thermal analysis(DTA)reveals two broad exothermic peaks for HMGC at 591℃and 697℃,whereas one exothermic peak at 820℃is detected for SMGC.X-ray diffraction(XRD)shows the crystallization of hematite as the sol phase in BPW,and meanwhile,Zn-ferrite and Ba-hexaferrite are identified in SMGC and HMGC,respectively.Transmission electron microscopy(TEM)reveals the crystallization of nanosize particles of~20 nm for SMGC and~12 nm for HMGC.Vibrating scanning magnetometer(VSM)reveals an increase in saturation magnetization from~1 emu/g for BPW to~77 emu/g for SMGC and 21 emu/g for HMGC.
文摘Processing biomaterials into porous scaffolds for bone tissueengineering is a critical and a key step in defining and controlling their physicochemical,mechanical,and biological properties.Biomaterials such as polymers are commonlyprocessed into porous scaffolds using conventional processing techniques,e.g.,saltleaching.However,these traditional techniques have shown unavoidable limitations andseveral shortcomings.For instance,tissue-engineered porous scaffolds with a complexthree-dimensional(3D)geometric architecture mimicking the complexity of theextracellular matrix of native tissues and with the ability to fit into irregular tissue defectscannot be produced using the conventional processing techniques.3D printing hasrecently emerged as an advanced processing technology that enables the processing ofbiomaterials into 3D porous scaffolds with highly complex architectures and tunableshapes to precisely fit into irregular and complex tissue defects.3D printing providescomputer-based layer-by-layer additive manufacturing processes of highly precise andcomplex 3D structures with well-defined porosity and controlled mechanical propertiesin a highly reproducible manner.Furthermore,3D printing technology provides anaccurate patient-specific tissue defect model and enables the fabrication of a patientspecifictissue-engineered porous scaffold with pre-customized properties.
基金a National Research Foundation of Korea(NRF)grant funded by the Ministry of Science and ICT(2019R1C1C1002490,2018R1A2B3003446)by the Global Research Development Center Program(2018K1A4A3A01064257)by the Priority Research Center Program provided by the Ministry of Education(2019R1A6A1A11034536)。
文摘Therapeutic options are quite limited in clinics for the successful repair of infected/degenerated tissues.Although the prevalent treatment is the complete removal of the whole infected tissue,this leads to a loss of tissue function and serious complications.Herein the dental pulp infection,as one of the most common dental problems,was selected as a clinically relevant case to regenerate using a multifunctional nanotherapeutic approach.For this,a mesoporous bioactive glass nano-delivery system incorporating silicate,calcium,and copper as well as loading epidermal growth factor(EGF)was designed to provide antibacterial/pro-angiogenic and osteo/odontogenic multiple therapeutic effects.Amine-functionalized Cu-doped bioactive glass nanospheres(Cu-BGn)were prepared to be 50–60 nm in size,mesoporous,positive-charged and bone-bioactive.The Cu-BGn could release bioactive ions(copper,calcium and silicate ions)with therapeutically-effective doses.The Cu-BGn treatment to human umbilical vein endothelial cells(HUVEC)led to significant enhancement of the migration,tubule formation and expression of angiogenic gene(e.g.vascular endothelial growth factor,VEGF).Furthermore,the EGF-loaded Cu-BGn(EGF@Cu-BGn)showed pro-angiogenic effects with antibacterial activity against E.faecalis,a pathogen commonly involved in the pulp infection.Of note,under the co-culture condition of HUVEC with E.faecalis,the secretion of VEGF was up-regulated.In addition,the osteo/odontogenic stimulation of the EGF@Cu-BGn was evidenced with human dental pulp stem cells.The local administration of the EGF@Cu-BGn in a rat molar tooth defect infected with E.faecalis revealed significant in vivo regenerative capacity,highlighting the nanotherapeutic uses of the multifunctional nanoparticles for regenerating infected/damaged hard tissues.
