Cytotoxicity and genome-wide microarray analysis of intestinal smooth muscle cells in response to hexavalent chromium induction

Chronic ingestion of high concentrations of hexavalent chromium[Cr(VI)]in drinking water induces intestinal tumors in mice;however,information on its toxicity on intestinal smooth muscle cells is limited.The present study aimed to assess the in vitro and in vivo toxicological effects of Cr(VI)on intestinal smooth muscle cells.Human intestinal smooth muscle cells(HISM cells)were cultured with different concentrations of Cr(VI)to evaluate effects on cell proliferation ability,oxidative stress levels,and antioxidant system.Furthermore,tissue sections in Cr(VI)exposed rabbits were analyzed to evaluate toxicity on intestinal muscle cells in vivo.Gene chips were utilized to assess differential gene expression profiles at the genome-wide level in 1μmol/L Cr(VI)treated cells.Intestinal tissue biopsy results showed that Cr(VI)increased the incidences of diffuse epithelial hyperplasia in intestinal jejunum but caused no obvious damage to the structure of the muscularis.Cell proliferation analysis revealed that high concentrations(≥64μmol/L)but not low concentrations of Cr(VI)(≤16μmol/L)significantly inhibited the growth of HISM cells.For oxidative stress levels,the expression of reactive oxygen species(ROS)and nitric oxide(NO)was elevated at high concentrations(≥64μmol/L)but not at low concentrations of Cr(VI)(≤16μmol/L).In addition,dose-dependent increases in the activity of oxidized glutathione(GSSH)/total-glutathione(T-GSH)were also observed.Gene chip screened 491 differentially expressed genes including genes associated with cell apoptosis,oxidations,and cytoskeletons.Some of these differentially expressed genes may be unique to smooth muscle cells in response to Cr(VI)induction.

Cytotoxicity and genome-wide microarray analysis of intestinal smooth muscle cells in response to hexavalent chromium induction

Chronic ingestion of high concentrations of hexavalent chromium [Cr（VI）] in drinking water induces intestinal tumors in mice; however, information on its toxicity on intestinal smooth muscle cells is limited. The present study aimed to assess the in vitro and in vivo toxicological effects of Cr（VI） on intestinal smooth muscle cells. Human intestinal smooth muscle cells （HISM cells） were cultured with different concentrations of Cr（VI） to evaluate effects on cell proliferation ability, oxidative stress levels, and antioxidant system. Furthermore, tissue sections in Cr（VI） exposed rabbits were analyzed to evaluate toxicity on intestinal muscle cells in vivo. Gene chips were utilized to assess differential gene expression profiles at the genome-wide level in 1 gmol/L Cr（VI） treated cells. Intestinal tissue biopsy results showed that Cr（VI） increased the incidences of diffuse epithelial hyperplasia in intestinal jejunum but caused no obvious damage to the structure of the muscularis. Cell proliferation analysis revealed that high concentrations （〉__64 gmol/L） but not low concentrations of Cr（VI） （〈16 ~tmol/L） significantly inhibited the growth of HISM cells. For oxidative stress levels, the expression of reactive oxygen species （ROS） and nitric oxide （NO） was elevated at high concentrations （〉64 pmol/L） but not at low concentrations of Cr（VI） （〈16 pmol/L）. In addition, dose-dependent increases in the activity of oxidized glutathione （GSSH）/total-glutathione （T-GSH） were also observed. Gene chip screened 491 differentially expressed genes including genes associated with cell apoptosis, oxidations, and cytoskeletons. Some of these differentially expressed genes may be unique to smooth muscle cells in response to Cr（VI） induction.

Carbon nanofibers embedded with Fe-Co alloy nanoparticles via electrospinning as lightweight high-performance electromagnetic wave absorbers

As a lot of electromagnetic pollution and interference issues have emerged,to overcome electromagnetic interference,prevent electromagnetic hazards,and develop new high-performance electromagnetic wave(EMW)absorbers have become a significant task in the field of materials science.In this paper,a three-dimensional(3D)carbon nanofibers network with core-shell structure,embedded with varied molar ratios of iron and cobalt(4:0,3:1,2:2,1:3,0:4),was effectively synthesized(Fe/Co@C-CNFs)via electrospinning.The phase,microstructure,magnetic and EMW absorption properties were studied.It is discovered that Fe/Co@C-CNFs doped with iron:cobalt=1:1 have excellent EMW absorption capacity.When the matching thickness is 1.08 mm,the minimum reflection loss(RL)value is-18.66 dB,while the maximum effective absorption bandwidth(EAB)reaches 4.2 GHz(13.9-18 GHz)at a thickness of 1.22 mm.This is owing to the absorbers'superior impedance matching and multiple reflections as well as the conductivity,dielectric,and magnetic losses of carbon nanofibers embedded with Fe-Co alloy particles.In addition,the radar cross section(RCS)of the absorbers has been calculated by CST Studio Suite,showing that the absorbing coating can effectively reduce the RCS at various angles,especially for Fe/Co@C-CNFs doped with iron:cobalt=1:1.These findings not only provide new insights for the preparation of light-weight and high-performance electromagnetic wave absorbers,but also contribute to energy storage and conversion.

Magnetic properties and special morphology of barium ferrite via electrospinning

Barium ferrite micro-/nanofibers with special morphology,nanowires with diameters of 100 nm,nanoribbons with diameters of 1μm,and nanotubes with outer diameter of about 300 nm while inner diameter of 100 nm were successfully prepared via electrospinning using different solvents（dimethyl formamide（DMF）,solutions of deionized water and ethyl alcohol,and solutions of deionized water and acetic acid,respectively）.The barium ferrite micro-/nanofibers were characterized by scanning electron microscope（SEM）,X-ray diffraction analysis（XRD）,and vibration sample magnetometer（VSM）.The results demonstrate that the pure BaFe12O19 ferrite phase is successfully formed.And the SEM results show excellent morphologies.The magnetic hysteresis loops demonstrate that their magnetic properties are quite different with different morphologies.The specific saturation magnetization is approximately the same（46.12-49.17 A·m^2·kg^-1）,but the coercivity of the BaFe12O19 increases from wires（190.08 kA·m^-1）,ribbons（224.16 kA·m^-1） to tubes（258.88 kA·m^-1）.

Electromagnetic attenuation property of multiphase Fe–Fe_3O_4–Al_2O_3 cermets near percolation threshold

Cermets are widely applied as attenuating materials due to high electromagnetic loss and better mechanical properties. In this paper, multiphase cermets composed of iron, iron oxide and alumina were successfully prepared by a two-step in situ synthesis process,which includes pressureless sintering and a selective reduction in hydrogen atmosphere. The phase composition and microstructure of cermets were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM), respectively. It is shown that nanosized cuboid Fe particles and octahedral FeOparticles are distributed in alumina matrix. The permittivity and permeability of composites were tested with radio frequency impedance analyzer(0.01–1.00 GHz). The results show that permittivity presents obvious frequency dispersion. Furthermore,dielectric constants of multiphase cermets get enlarged due to the enhancement of interfacial polarization. On the other hand, there is a magnetic loss peak in permeability spectra,which indicates typical relaxation behavior. It is possible to achieve better electromagnetic attenuation property by adjusting process parameters.