scholarly journals Changes in Ultrastructure and Fourier Transform Infrared Spectrum of Salmonella enterica Serovar Typhimurium Cells after Exposure to Stress Conditions

2010 ◽  
Vol 76 (22) ◽  
pp. 7598-7607 ◽  
Author(s):  
A. Alvarez-Ordóñez ◽  
M. Prieto
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Stress Response ◽  
Salmonella Enterica ◽  
Fourier Transform Infrared ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
Serovar Typhimurium ◽  
Ft Ir

ABSTRACT The effect of exposure to acid (pH 2.5), alkaline (pH 11.0), heat (55°C), and oxidative (40 mM H2O2) lethal conditions on the ultrastructure and global chemical composition of Salmonella enterica serovar Typhimurium CECT 443 cells was studied using transmission electron microscopy and Fourier transform infrared spectroscopy (FT-IR) combined with multivariate statistical methods (hierarchical cluster analysis and factor analysis). Infrared spectra exhibited marked differences in the five spectral regions for all conditions tested compared to those of nontreated control cells, which suggests the existence of a complex bacterial stress response in which modifications in a wide variety of cellular compounds are involved. The visible spectral changes observed in all of the spectral regions, together with ultrastructural changes observed by transmission electron microscopy and data obtained from membrane integrity tests, indicate the existence of membrane damage or alterations in membrane composition after heat, acid, alkaline, and oxidative treatments. Results obtained in this study indicate the potential of FT-IR spectroscopy to discriminate between intact and injured bacterial cells and between treatment technologies, and they show the adequacy of this technique to study the molecular aspects of bacterial stress response.

Synthesis of Fe 3+-Dopped PANI Conductive Nanomaterials via Interfacial Polymerization

2011 ◽  
Vol 239-242 ◽  
pp. 2839-2842
Author(s):  
Hong Mei Mu ◽  
Peng Fei ◽  
Bi Tao Su ◽  
Zi Qiang Lei
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Interfacial Polymerization ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Conductive Nanomaterials ◽  
Ft Ir Spectroscopy

A series of Fe3+-dopped polyaniline (Fe3+/PANI) nanomaterials with different morphologies and a higher conductivity were successfully synthesized using a simple and static interfacial polymerization by using FeCl3 as both oxidant catalyst and dopant. The effect of surfactants CTAB and SDS and the concentration of FeCl3 on the morphology and conductivity of Fe3+/PANI nanomaterial were investigated. The samples were characterized by Transmission Electron Microscopy (TEM), SDY-4 probes conductivity meter, X-ray Diffractometry (XRD), Energy dispersive spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy techniques. TEM’s results showed that their morphologies changed with the type of the surfactant and the concentration of FeCl3. Introducing surfactants CTAB and SDS into Fe3+/PANI remarkably improved the conductivity of the material. The conductivities of CTAB/Fe3+/PANI and SDS /Fe3+/PANI nanomaterials were respectively about 4.8×10-2 and 1.3×10-2 S/cm while the conductivity of Fe3+/PANI was found to be 1.5×10-4 S/cm. The different morphology and high conductivity may be ascribed to the mutual effects of the surfactant and oxidant.

Preparation of carbon nanotubes/porous polyimide composites for effective adsorption of 2,4-dichlorophenol

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95825-95835 ◽  
Author(s):  
Hui Yuan ◽  
Qing liang You ◽  
Lin Jie Song ◽  
Gui ying Liao ◽  
Hua Xia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Thermogravimetric Analysis ◽  
Fourier Transform Infrared ◽  
Transmission Electron ◽  
Infrared Spectrometer ◽  
Polyimide Composites ◽  
Adsorption Desorption

The carbon nanotubes (CNT)/polyimide (PI) composites were prepared by blending and characterized by Fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and N2adsorption–desorption.

scholarly journals Sintesis Nanopartikel Nickel Ferrite (NiFe2O4) dengan Metode Kopresipitasi dan Karakterisasi Sifat Kemagnetannya (Halaman 20 s.d. 25)

2015 ◽  
Vol 19 (56) ◽  
Author(s):  
Muflihatun ◽  
Siti Shofiah ◽  
Edi Suharyadi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Nickel Ferrite ◽  
Fourier Transform Infrared ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Nanopartikel Nikel Ferit (NiFe2O4) telah disintesis dengan metode kopresipitasi dengan memvariasi konsentrasi NaOH dan suhu sintesis. Struktur kristal, ukuran partikel, dan morfologi dari sampel dianalisa menggunakan X-ray diffraction (XRD) dan transmission electron microscopy (TEM). Ukuran butir pada konsentrasi NaOH 3, 5, dan 10 M masing-masing adalah 5,7; 4,3; dan 4,2 nm, sedangkan pada suhu 60, 80, dan 150°C berturut-turut adalah 4,2; 4,9; dan 5,5 nm. Analisa fourier transform infrared (FTIR) menunjukkan dua puncak serapan pada rentang ~400-600 cm-1 yang terkait dengan site oktahedral dan tetrahedral pada struktur NiFe2O4. Sifat magnetik NiFe2O4 hasil analisa vibrating sample magnetometer (VSM) menunjukkan bahwa sampel berperilaku ferromagnetik dengan nilai koersivitasnya pada rentang 42-47 Oe. Sampel dengan variasi konsentrasi NaOH, koersivitasnya cenderung menurun dengan menurunnya ukuran partikel. Sementara sampel dengan variasi suhu, semakin kecil ukuran partikel, koersivitasnya cenderung meningkat. Pada 15 kOe, nilai magnetisasi terbesar (6,17 emu/g) diperoleh pada sampel dengan rasio fasa α-Fe2O3 paling rendah.

Carbonate and cation substitutions in hydroxylapatite in breast cancer micro-calcifications

2021 ◽  
pp. 1-11
Author(s):  
Yan Zhang ◽  
Changqiu Wang ◽  
Yan Li ◽  
Anhuai Lu ◽  
Fanlu Meng ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Synchrotron Radiation ◽  
Optical Microscopy ◽  
Fourier Transform Infrared ◽  
X Ray ◽  
Transmission Electron ◽  
Cation Substitutions

Abstract Calcification within breast cancer is a diagnostically significant radiological feature that generally consists of hydroxylapatite. Samples from 30 cases of breast carcinoma with calcification were investigated using optical microscopy, energy-dispersive X-ray analysis, transmission-electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, synchrotron radiation X-ray diffraction and X-ray fluorescence. Under optical microscopy, the calcifications were found to consist of either irregular aggregates with widths > 200 μm or spherical aggregates similar to psammoma bodies with an average diameter of 30 μm. Transmission-electron microscopy showed that short columnar or dumbbell-shaped crystals with widths of 10–15 nm and lengths of 20–50 nm were the most common morphology; spherical aggregates (~1 μm in diameter) with amorphous coatings of fibrous nanocrystals were also observed. Results indicated that hydroxylapatite was the dominant mineral phase in the calcifications, and both CO32– and cation substitutions (Na, Mg, Zn, Fe, Sr, Cu and Mn) were present in the hydroxylapatite structure. Fourier-transform infrared spectra show peaks at 872 and 880 cm–1 indicating that CO32– substituted both the OH– (A type) and PO43– (B type) sites of hydroxylapatite, making it an A and B mixed type. The ratio of B- to A-type substitution was estimated in the range of 1.1–18.7 from the ratio of peak intensities (I872/I880), accompanied with CO32– contents from 1.1% to 14.5%. Trace arsenic, detected in situ by synchrotron radiation X-ray fluorescence was found to be distributed uniformly in the calcifications in the form of AsO43– substituting for PO43–. It is therefore proposed that identifying these trace elements in breast cancer calcifications may be promising for future clinical diagnostics.

scholarly journals Extracellular Biofabrication, Characterization, and Antimicrobial Efficacy of Silver Nanoparticles Loaded on Cotton Fabrics Using Newly IsolatedStreptomycessp. SSHH-1E

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Noura El-Ahmady El-Naggar ◽  
Attiya Mohamedin ◽  
Sarah Shawqi Hamza ◽  
Abdel-Dayem Sherief
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Cell Free Supernatant ◽  
Transmission Electron ◽  
Vis Spectroscopy

Biological method for silver nanoparticles synthesis has been developed to obtain cost effective, clean, nontoxic, and ecofriendly size-controlled nanoparticles. The objective of this study is extracellular biosynthesis of antimicrobial AgNPs using cell-free supernatant of a localStreptomycessp. strain SSHH-1E. Different medium composition and fermentation conditions were screened for maximal AgNPs biosynthesis using Plackett-Burman experimental design and the variables with statistically significant effects were selected to study their combined effects and to find out the optimum values using a Box-Behnken design. The synthesized AgNPs were characterized using UV-visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. Rapid biosynthesis of AgNPs was achieved by addition of 1 mM AgNO3solution to the cell-free supernatant. The produced particles showed a single surface plasmon resonance peak at 400 nm by UV-Vis spectroscopy which confirmed the presence of AgNPs.Streptomycessp. SSHH-1E was identified asStreptomyces narbonensisSSHH-1E. Transmission electron microscopy study indicated that the shape of AgNPs is spherical and the size is ranging from 20 to 40 nm. Fourier transform infrared spectroscopy analysis provides evidence for proteins as possible reducing and capping agents. Furthermore, the biosynthesized AgNPs significantly inhibited the growth of medically important pathogenic Gram-positive and Gram-negative bacteria and yeast. The maximum biosynthesis of AgNPs was achieved at initial pH of 8, peptone of 0.5 g, and inoculum age of 48 h. The statistical optimization resulted in a 4.5-fold increase in the production of AgNPs byStreptomyces narbonensisSSHH-1E.

Polyoxometalate and copolymer-functionalized ionic liquid catalyst for esterification

2011 ◽  
Vol 84 (3) ◽  
pp. 541-551 ◽  
Author(s):  
Huan Li ◽  
Jizhong Chen ◽  
Li Hua ◽  
Yunxiang Qiao ◽  
Yinyin Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ionic Liquid ◽  
Fourier Transform ◽  
Room Temperature ◽  
Homogeneous Solution ◽  
Imidazolium Cation ◽  
Transmission Electron ◽  
Ft Ir ◽  
Halogen Free

A new room-temperature ionic liquid (RTIL) consisting of a polyoxometalate (POM) anion and tri-block copolymer (P123)-functionalized imidazolium cation was synthesized and utilized as a halogen-free catalyst for esterification. The catalytic system was a homogeneous solution at the beginning of the reaction, but an emulsion formed during the course of the reaction, and a progressive phase separation of the catalyst occurred at 0 °C over the course of 3 h. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform/infrared spectroscopy (FT/IR) have been used to characterize the properties of the IL during the reaction. The new IL catalyst was found to be highly efficient in the esterification of various alcohols and can be recycled at least seven times.

Organophilic Modification and Application of Nano-Fumed Silica in Pervaporation of Ethanol / Water Mixture

2011 ◽  
Vol 117-119 ◽  
pp. 679-682
Author(s):  
Bing Bing Li ◽  
Liang Wang ◽  
De Sun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fourier Transform ◽  
Fumed Silica ◽  
Water Mixture ◽  
Transmission Electron ◽  
Ft Ir ◽  
Scanning Electron ◽  
Better Than

Fumed Silica was modified with hexamethyldisiazane (HMDZ, modifier) and dimethyldiethoxysilane (DMDEOS, co-modifier) by grafting method. The structure of organo-functionnalized nanoparticles was characterized by fourier transform infrared spectrum (FT-IR) and transmission electron microscopy (TEM). Functional nanosilica-filled polydimethylsiloxane(PDMS) composites membrane were prepared. Scanning electron microscopy (SEM) observations of composites revealed good dispersion of the silica nanoparticles and the pervaporation performance of the filled PDMS membranes is better than that of the unfilled PDMS membranes.

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