Characterization of the SiO2 film deposited by using plasma enhanced chemical vapor deposition (PECVD) with TEOS/N2/O2

The purpose of this study was to examine how certain parameters like temperature, pressure, and gas composition affect the characteristics of SiO2 film by Plasma Enhanced Chemical Vapor Deposition (PECVD). We used of low temperature and an inductively coupled plasma (ICP) for various with gas mixtures of TEOS/N2/O2 at a given RF power and dc bias voltage. For the gas mixture with 40 sccm of N2 in TEOS, 100 standard cubic centimeters per minute (sccm) of N2, and 500 sccm of O2, transparent and scratch-resistant SiO2 could be deposited with a deposition rate of 30 nm/min when RF power of 500 W and a dc-bias voltage of 350V were applied. The characteristics of the deposited SiO2, such as the composition, the binding energy, etc. were compared with the SiO2 deposited by using thermal CVD and evaporation. It was found that the SiO2 deposited by PECVD with TEOS/N2/O2 exhibited properties typical of SiO2 deposited applying thermal CVD and evaporation. The surface roughness of the 100 nm-thick SiO2 deposited by PECVD was similar to that of the substrate

Properties of Silicon Dioxide Film Deposited By PECVD at Low Temperature/Pressure

conventional plasma enhanced chemical vapor deposition (PECVD) at low temperature/pressure with silane (SiH4) and nitrous oxide (N2O) as precursor gases. The ellipsometer and stress measurement system were used to test the thickness and refractive index uniformity of the SiO2 film fabricated. The effects of radio frequency (RF) power chamber pressure and N2O/SiH4 flow ratio on the properties of SiO2 film were studied. The results show that the refractive index of SiO2 film is mainly determined by N2O/SiH4 flow ratio .Moreover, the formation of SiO2 thin films is confirmed by Fourier transform infrared (FTIR) spectroscopy. The thickness and refractive indices of the films measured by ellipsometry C-V measurement show that the electrical properties are directly related to process parameters and Si/SiO2 interface. The MIS structures were also fabricated from optimized SiO2 layer to study C-V measurement and to estimate interface, oxide and effective border traps density. The deposited SiO2 films have good uniformity, compact structure, high deposition rate, low deposition temperature and controllable stress, which can be widely, used in semiconductor devices.  http://dx.doi.org/10.5937/metmateng1402089

Properties of Silicon Dioxide Film Deposited By PECVD at Low Temperature/Pressure

conventional plasma enhanced chemical vapor deposition (PECVD) at low temperature/pressure with silane (SiH4) and nitrous oxide (N2O) as precursor gases. The ellipsometer and stress measurement system were used to test the thickness and refractive index uniformity of the SiO2 film fabricated. The effects of radio frequency (RF) power chamber pressure and N2O/SiH4 flow ratio on the properties of SiO2 film were studied. The results show that the refractive index of SiO2 film is mainly determined by N2O/SiH4 flow ratio .Moreover, the formation of SiO2 thin films is confirmed by Fourier transform infrared (FTIR) spectroscopy. The thickness and refractive indices of the films measured by ellipsometry C-V measurement show that the electrical properties are directly related to process parameters and Si/SiO2 interface. The MIS structures were also fabricated from optimized SiO2 layer to study C-V measurement and to estimate interface, oxide and effective border traps density. The deposited SiO2 films have good uniformity, compact structure, high deposition rate, low deposition temperature and controllable stress, which can be widely, used in semiconductor devices. http://dx.doi.org/10.5937/metmateng1402089

Characterization of the SiO2 film deposited by using plasma enhanced chemical vapor deposition (PECVD) with TEOS/N2/O2

The purpose of this study was to examine how certain parameters like temperature, pressure, and gas composition affect the characteristics of SiO2 film by Plasma Enhanced Chemical Vapor Deposition (PECVD). We used of low temperature and an inductively coupled plasma (ICP) for various with gas mixtures of TEOS/N2/O2 at a given RF power and dc bias voltage. For the gas mixture with 40 sccm of N2 in TEOS, 100 standard cubic centimeters per minute (sccm) of N2, and 500 sccm of O2, transparent and scratch-resistant SiO2 could be deposited with a deposition rate of 30 nm/min when RF power of 500 W and a dc-bias voltage of 350V were applied. The characteristics of the deposited SiO2, such as the composition, the binding energy, etc. were compared with the SiO2 deposited by using thermal CVD and evaporation. It was found that the SiO2 deposited by PECVD with TEOS/N2/O2 exhibited properties typical of SiO2 deposited applying thermal CVD and evaporation. The surface roughness of the 100 nm-thick SiO2 deposited by PECVD was similar to that of the substrate

Growth kinetics and characterization of human dental pulp stem cells: comparison between third molar and first premolar teeth

Dental pulp stem cells (DPSCs) play an important role in tissue regeneration. This study compares the growth kinetics and characterization of third molar and first premolar human DPSCs. Dental pulp tissues were isolated from human first premolar and third molar teeth and were digested by treating them with collagenase type I. Single-cell suspensions from each dental pulp were seeded in T25 culture flasks and the media were replaced every 3 days until 70% confluence. The cells were enumerated to determine the population doubling time (PDT). Cells were characterized using flow cytometry, RT-PCR and osteogenic medium for differentiation of DPSCs. Karyotyping assay was also performed till passage 7th. The DPSCs had spindle-shaped morphology. There was an increase in PDT in third molar DPSCs when compared to first premolar teeth. Positive expression of CD44, CD73, and CD90 and negative expression of CD34 and CD45 were illustrated. A normal karyotype was visible for all seven passages. The Alizarin red staining was positive for osteogenic induction of DPSCs. When DPSCs are needed, third molar teeth can be a good and convenient candidate for cell transplantation, yielding high number of cells with mesenchymal characteristics. They can be a source for further investigations in vitro and work on tissue engineering protocols

Caprine Endometrial Mesenchymal Stromal Stem Cell: Multilineage Potential, Characterization, and Growth Kinetics in Breeding and Anestrous Stages

The endometrial layer of the uterus contains a population of cells with similar characteristics of mesenchymal stem cells (MSCs). In the present study, caprine endometrial mesenchymal stromal stem cells (En-MSCs) characters and differentiation potential to chondrogenic, osteogenic, and adipogenic cell lines as well as their growth kinetics in breeding and anestrous stages were evaluated. En-MSCs were enzymatically isolated from endometrial layer of the uterus of adult goats and were cultured and subcultured until passage 4. The growth kinetics and population doubling time (PDT) of caprine En-MSCs in breeding and anestrous stages were determined. En-MSCs in passage 4 were used for the karyotyping and differentiation into chondrocytes, osteocytes, and adipocytes. The PDT in anestrus phase was 40.6 h and in cyclic goats was 53 h. En-MSCs were fibroblast-like in all passages. The number of chromosomes was normal (2n=60) with no chromosomal instability. Chondrogenic, osteogenic, and adipogenic differentiation of En-MSCs was confirmed by staining with Alcian blue, Alizarin red, and Oil Red O, respectively. Caprine En-MSCs demonstrated to be an alternative source of MSCs for cell therapy purposes in regenerative medicine

Establishment, Culture, and Characterization of Guinea Pig Fetal Fibroblast Cell

Establishment of Guinea pig fetal fibroblast cells and their biological evaluation before and after cryopreservation were the main purposes of this study. After determination of the proper age of pregnancy by ultrasonography, 30 days old fetuses of Guinea pigs were recovered. Their skins were cut into small pieces (1 mm2) and were cultured. When reaching 80–90% confluence, the cells were passaged. Cells of the second and eighth passages were cultured in 24-well plates (4×104 cells/well) for 6 days and three wells per day were counted. The average cell counts at each time point were then plotted against time and the population doubling time (PDT) was determined. Then, vials of cells (2×106 cells/mL) were cryopreserved for 1 month and after thawing, the cell viability was evaluated. The PDT of the second passage was about 23 h and for the eighth passage was about 30 h. The viability of the cultures was 95% in the second passage and 74.5% in the eighth passage. It was shown that the Guinea pig fetal fibroblast cell culture can be established using the adherent culture method while, after freezing, the viability indices of these cells were favorable

Superparamagnetic Iron Oxide-Labeled Leishmania major Can Be Traced in Fibroblasts

Introduction. Leishmaniasis is still a neglected tropical disease that can endanger more than 350 million people among 98 countries. Leishmania can survive in fibroblasts as latent inactive forms. This study was conducted to evaluate the role of superparamagnetic iron oxide nanoparticles (SPIONs) in cell culture for tracking the labeled Leishmania major in fibroblasts. Methods. Dextran-coated SPIONs were used for labeling L. major in co-culture of fibroblasts with the parasite. To quantify and trace SPION-labeled Leishmania, Prussian blue staining was undertaken. Fibroblast characterization was undertaken by real time polymerase chain reaction. Transmission electron microscope (TEM) was used for confirming the entry of the labeled L. major to the cytoplasm and the nucleus of the fibroblast. Results. Fibroblasts were spindle-shaped and adherent to culture flasks. Promastigotes were with thin elongated lance-like morphology with an anterior kinetoplast and an emergent free flagellum. Prussian blue staining revealed that internalized SPIONs were localized within cytoplasm and nucleus of the fibroblasts after 24 hours of culture. Prussian blue staining successfully showed the presence of iron (stained blue) in labeled L. major within the fibroblasts. This finding was confirmed by TEM, and labeled L. major was detected in the fibroblast cytoplasm and nucleus too. Conclusion. We can conclude that SPIONs are safe, inexpensive, easy to use, and accurate, and a fast method to label Leishmania parasite in cells that the parasite can be latent, such as fibroblasts. These findings can open a new window in diagnosis, pathogenesis, and treatment of cutaneous leishmaniasis and can be added to the literature

The anti-Alzheimer potential of novel spiroindolin-1,2-diazepine derivatives as targeted cholinesterase inhibitors with modified substituents

Abstract In this study, a new series of spiro indolin-1,2-diazepine were designed, synthesized, and screened for their cholinesterase inhibitory activities. A novel, green, high-yielding approach was constructed to synthesize spiro indolin-1,2-diazepine derivatives through a cascade reaction of different isatins, malononitrile and 1,1-enediamines (EDAMs) via sequential four-component reactions to produce the target compounds with good to excellent yields. Next the inhibitory potencies of all derivatives were determined spectroscopically at 415 nm using the modified Ellman method. The results of the in vitro screening indicated that 5l with spiroindolin-1,2-diazepine core bearing 5-NO2 at R1 and 4-OH at R2 was the most potent and selective AChE inhibitor with an IC50 value of 3.98 ± 1.07 µM with no significant inhibition against BChE while 5j was the most active analog against both AChE and BChE enzymes. The structure–activity relationships suggested the variation in the inhibitory activities of derivatives was affected by different substitutions on the indolinone ring as well as the phenyl moiety. The enzyme kinetic studies of the most potent compound 5l at five different concentrations and acetylthiocholine substrate (0.1–1 mM) by Ellman's method revealed that it inhibited AChE in a mixed mode with a K i of 0.044 μM. A molecular docking study was performed via induced fit docking protocol to predict the putative binding interaction. It was shown that the moieties used in the initial structure design play a fundamental role in interacting with the enzyme's binding site. Further, molecular dynamics simulations with the Schrödinger package were performed for 5l in a complex with AChE and revealed that compound 5l formed the stable complex with the enzyme. The MTT toxicity assessments against the neuroblastoma cell line were executed, and no toxicity was seen for 5l under the tested concentrations

Epidemiological aspect of scorpion sting in Bandar Abbas, Iran, during 2009–2011

Introduction: People in tropical and semi-tropical areas are in danger of scorpion sting, and this can be a serious problem for them. Mortality due to scorpion sting in the tropical and semi-tropical areas of Iran is about 75%, and this makes scorpion sting in these areas a serious medical problem. Because of this problem, our aim was to assess the epidemiological aspects of scorpion sting in Bandar Abbas, Iran, during 2009-2011. Methods: In this cross-sectional retrospective study, epidemiologic data of 698 scorpion sting cases, who were referred to the Shahid Mohamadi Hospital of Bandar Abbas in Hormozgan Province collected from 2009 until 2011. The data included demographic and individual information, such as age, gender, geographic location, bite site, when the incident occurred, and anti-venom consumption. The required data were extracted from the patients’ recorded information in the Hospital, and we recorded data in a special checklist and imported the data into the computer for statistical analysis using of SPSS software, version 21.0. Descriptive statistics, including mean, standard deviation, frequency, and percentage, were used for data analysis. Results: Two hundred and sixty-one (37.4%) of the cases were urban and 437(62.6%) were rural. Males comprised 50.1% of the cases, and women comprised 49.9% (p >0.05). Twenty-five point two percent of scorpion sting cases occurred among people in the 21 to 30 age group, and there were very few cases among people in the 51 to 60 age range (p<0.05). Most of cases were recorded in April and October, and the fewest cases were recorded in July and January (p<0.05); also 32.2% of scorpion sting cases occurred after midnight and in the early morning hours. Conclusion: Our survey showed that there was a high incidence of scorpion stings in rural areas, among 21-30 age group, among housekeepers, and among students. These results indicate the need for public education programs and better sanitation services in the rural areas around Bandar Abbas city. Prospective studies can help to health and medicine organization for prevention and treatment of scorpion sting