scholarly journals Light promoted brown staining of protoplasm by Ag+ is ideal to test wheat pollen viability rapidly

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243856
Author(s):  
Abhishek Biswas ◽  
Subramaniyan Divya ◽  
Peddisetty Sharmila ◽  
Peddisetty Pardha-Saradhi
Keyword(s):  
Pollen Viability ◽  
Wheat Breeding ◽  
Live Cells ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Viable Pollen ◽  
X Ray ◽  
Transmission Electron ◽  
Resonance Band ◽  
Microscopic Studies

Pollen viability is crucial for wheat breeding programs. The unique potential of the protoplasm of live cells to turn brown due to the synthesis of silver nanoparticles (AgNPs) through rapid photoreduction of Ag+, was exploited for testing wheat pollen viability. Ag+-viability test medium (consisting of 0.5 mM AgNO3 and 300 mM KNO3) incubated with wheat pollen turned brown within 2 min under intense light (~600 μmol photon flux density m-2s-1), but not in dark. The brown medium displayed AgNPs-specific surface plasmon resonance band in its absorption spectrum. Light microscopic studies showed the presence of uniformly stained brown protoplasm in viable pollen incubated with Ag+-viability medium in the presence of light. Investigations with transmission electron microscope coupled with energy dispersive X-ray established the presence of distinct 5–35 nm NPs composed of Ag. Powder X-ray diffraction analysis revealed that AgNPs were crystalline and biphasic composed of Ag0 and Ag2O. Conversely, non-viable pollen and heat-killed pollen did not turn brown on incubation with Ag+-medium in light. We believe that the viable wheat pollen turn brown rapidly by bio-transforming Ag+ to AgNPs through photoreduction. Our findings furnish a novel simplest and rapid method for testing wheat pollen viability.

A high-throughput assembly of beam-shaping channel-cut monochromators for laboratory high-resolution X-ray diffraction and small-angle X-ray scattering experiments

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Peter Nadazdy ◽  
Jakub Hagara ◽  
Petr Mikulik ◽  
Zdenko Zaprazny ◽  
Dusan Korytar ◽  
...  
Keyword(s):  
High Resolution ◽  
Small Angle ◽  
Photon Flux ◽  
Photon Flux Density ◽  
X Ray Diffraction ◽  
High Beam ◽  
X Ray ◽  
X Ray Scattering ◽  
Beam Collimation ◽  
Ray Scattering

A four-bounce monochromator assembly composed of Ge(111) and Ge(220) monolithic channel-cut monochromators with V-shaped channels in a quasi-dispersive configuration is presented. The assembly provides an optimal design in terms of the highest transmittance and photon flux density per detector pixel while maintaining high beam collimation. A monochromator assembly optimized for the highest recorded intensity per detector pixel of a linear detector placed 2.5 m behind the assembly was realized and tested by high-resolution X-ray diffraction and small-angle X-ray scattering measurements using a microfocus X-ray source. Conventional symmetric and asymmetric Ge(220) Bartels monochromators were similarly tested and the results were compared. The new assembly provides a transmittance that is an order of magnitude higher and 2.5 times higher than those provided by the symmetric and asymmetric Bartels monochromators, respectively, while the output beam divergence is twice that of the asymmetric Bartels monochromator. These results demonstrate the advantage of the proposed monochromator assembly in cases where the resolution can be partially sacrificed in favour of higher transmittance while still maintaining high beam collimation. Weakly scattering samples such as nanostructures are an example. A general advantage of the new monochromator is a significant reduction in the exposure time required to collect usable experimental data. A comparison of the theoretical and experimental results also reveals the current limitations of the technology of polishing hard-to-reach surfaces in X-ray crystal optics.

scholarly journals Exploiting coherence for real-time studies by single-bunch imaging

2014 ◽  
Vol 21 (4) ◽  
pp. 815-818 ◽  
Author(s):  
A. Rack ◽  
M. Scheel ◽  
L. Hardy ◽  
C. Curfs ◽  
A. Bonnin ◽  
...  
Keyword(s):  
Real Time ◽  
European Synchrotron Radiation Facility ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Bunch Length ◽  
X Ray ◽  
Aqueous Foam ◽  
Insertion Device ◽  
X Ray Imaging ◽  
Absorption Contrast

First real-time studies of ultra-fast processes by single-bunch imaging at the European Synchrotron Radiation Facility are reported. By operating the storage ring of the ESRF in single-bunch mode with its correspondingly increased electron bunch charge density per singlet, the polychromatic photon flux density at insertion-device beamlines is sufficient to capture hard X-ray images exploiting the light from a single bunch (the corresponding bunch length is 140 ps FWHM). Hard X-ray imaging with absorption contrast as well as phase contrast in combination with large propagation distances is demonstrated using spatial samplings of 11 µm and 35 µm pixel size. The images acquired allow one to track crack propagation in a bursting piece of glass, breaking of an electrical fuse as well as cell wall rupture in an aqueous foam. Future developments and their potential in the frame of the proposed Phase II of the ESRF Upgrade Program are discussed.

Synthesis of nanometer-sized particles of barium orthotitanate prepared through a modified reverse micellar route: Structural characterization, phase stability and dielectric properties

2004 ◽  
Vol 19 (10) ◽  
pp. 2905-2912 ◽  
Author(s):  
Tokeer Ahmad ◽  
Ashok K. Ganguli
Keyword(s):  
Martensitic Transition ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Microscopic Studies ◽  
Size Of Particles ◽  
Reverse Micellar

Nanoparticles of barium orthotitanate (Ba2TiO4) was obtained using microemulsions (avoiding Ba-alkoxide). Powder x-ray diffraction studies of the powder after calcining at 800 °C resulted in a mixture of orthorhombic (70%) and monoclinic (30%) phases. The high-temperature orthorhombic form present at 800 °C was due to the small size of particles obtained by the reverse micellar route. Pure orthorhombic Ba2TiO4 was obtained on further sintering at 1000 °C with lattice parameters a = 6.101(2) Å, b =22.94(1) Å, c = 10.533(2) Å (space group, P21nb). The particle size obtained from x-ray line broadening studies and transmission electron microscopic studies was found to be 40–50 nm for the powder obtained after heating at 800 °C. Sintering at 1000 °C showed increase in grain size up to 150 nm. Our studies corroborate well with the presence of a martensitic transition in Ba2TiO4. The dielectric constant was found to be 40 for Ba2TiO4 (at 100 kHz) for samples sintered at 1000 °C. The dielectric loss obtained was low (0.06) at 100 kHz.

scholarly journals Ecofriendly Synthesis of Silver Nanoparticles from Garden Rhubarb (Rheum rhabarbarum)

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Palem Ramasubba Reddy ◽  
Shimoga D. Ganesh ◽  
Nabanita Saha ◽  
Oyunchimeg Zandraa ◽  
Petr Sáha
Keyword(s):  
Silver Nanoparticles ◽  
Silver Ions ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Plasmon Resonance Band ◽  
Transmission Electron ◽  
Resonance Band ◽  
Crystalline Nature

Bioreduction of silver ions following one pot process is described to achieveRheum rhabarbarum(RR) based silver nanoparticles (SNPs) which is termed as “RR-SNPs.” The Ultraviolet–visible spectroscopy (UV–vis) confirms the characteristic surface plasmon resonance band for RR-SNPs in the range of 420–460 nm. The crystalline nature of SNPs was confirmed by X-ray diffraction (XRD) peaks at 38.2°, 45.6°, 64.2°, and 76.8°. Transmission electron microscopy (TEM) and scanning electronic microscopy (SEM) confirm the shape of synthesized SNPs. They are roughly spherical but uniformly distributed, and size varies from 60 to 80 nm. These biogenic SNPs show persistent zeta potential value of 34.8 mV even after 120 days and exhibit potent antibacterial activity in presence ofEscherichia coli(CCM 4517) andStaphylococcus aureus(CCM 4516). In addition, cytotoxicity of RR-SNPs againstin vitrohuman epithelial carcinoma (HeLa) cell line showed a dose-response activity. The lethal concentration (LC50) value was found to be 28.5 μg/mL for RR-SNPs in the presence of HeLa cells. These findings help us to evaluate their appropriate applications in the field of nanotechnology and nanomedicine.

Low-cost Rolled X-ray Prism Lenses to increase photon flux density in diffractometry experiments

2014 ◽  
Vol 29 (2) ◽  
pp. 118-122 ◽  
Author(s):  
H. Vogt ◽  
A. Last ◽  
J. Mohr ◽  
F. Marschall ◽  
K.-U. Mettendorf ◽  
...  
Keyword(s):  
Low Cost ◽  
Steel Tube ◽  
Photon Flux ◽  
Photon Flux Density ◽  
X Rays ◽  
X Ray ◽  
Integrated Intensity ◽  
New Type ◽  
Institute Of Technology ◽  
Microstructure Technology

At the Institute of Microstructure Technology (IMT) of the Karlsruhe Institute of Technology (KIT), a new type of refractive X-ray optics has been developed. Owing to its comparably easy fabrication method and the large aperture, the so-called Rolled X-ray Prism Lenses (RXPL) have the potential to be used with X-ray tubes in an industrial environment as a low-cost alternative to existing optics. The lens itself is built out of a micro-structured foil which is cut into shape and rolled around a winding core to form a refracting element for X-rays. The resulting refractive structure can be used as illumination optics. Diffractometry experiments with an NIST 1976a sample were performed and showed up to an 18-fold enhanced integrated intensity compared to that acquired with a steel tube collimator.

Photoluminescent properties of nanocrystalline Sm3+-doped CaO–CeO2 system synthesized by an auto-igniting combustion synthesis technique

2018 ◽  
Vol 32 (22) ◽  
pp. 1850255 ◽  
Author(s):  
S. V. Aswathy ◽  
Meenu Venugopal ◽  
H. Padma Kumar
Keyword(s):  
Combustion Synthesis ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Solid State Method ◽  
X Ray ◽  
Transmission Electron ◽  
Microscopic Studies ◽  
Cie Chromaticity

This study investigates the optical properties of samarium-doped microstructured and nanostructured CaO–CeO2 mixed solutions. Conventional solid state method and auto-igniting combustion synthesis were used for the preparation of the samples. The as-prepared samples were characterized using X-ray diffraction, Fourier Transform Infrared spectroscopy, Transmission Electron Microscopy, UV-Visible spectroscopy and photoluminescence spectroscopy. A mixed phase formation with phases of CaO, CeO2 and Ca(OH)2 was observed form X-ray diffraction studies. The transmission electron microscopic studies have shown that the average particle size of the as-prepared powder was in the range of 30–40 nm. A blueshift is observed in the bandgap of the nanocrystalline samples. Strong orange–red emission was observed for Sm[Formula: see text]-doped samples and the chromaticity values were calculated using CIE chromaticity diagram.

scholarly journals High-dynamic-range transmission-mode detection of synchrotron radiation using X-ray excited optical luminescence in diamond

2020 ◽  
Vol 27 (3) ◽  
pp. 708-712
Author(s):  
Stanislav Stoupin ◽  
Sergey Antipov ◽  
Alexander M. Zaitsev
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Transmission Mode ◽  
Photon Flux ◽  
Photon Flux Density ◽  
X Rays ◽  
Defect States ◽  
X Ray ◽  
Diamond Plate ◽  
Optical Luminescence

Enhancement of X-ray excited optical luminescence in a 100 µm-thick diamond plate by introduction of defect states via electron beam irradiation and subsequent high-temperature annealing is demonstrated. The resulting X-ray transmission-mode scintillator features a linear response to incident photon flux in the range 7.6 × 108 to 1.26 × 1012 photons s−1 mm−2 for hard X-rays (15.9 keV) using exposure times from 0.01 to 5 s. These characteristics enable a real-time transmission-mode imaging of X-ray photon flux density without disruption of X-ray instrument operation.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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