Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

scholarly journals Radiographic aspects of acute community-acquired bacterial pneumonia and pulmonary tuberculosis in children

2021 ◽  
Author(s):  
Rivo Lova Herilanto Rakotomalala ◽  
Harimino Mireille Rakotondravelo ◽  
Andrianina Harivelo Ranivoson ◽  
Annick Lalaina Robinson
Keyword(s):  
Community Acquired Pneumonia ◽  
University Hospital ◽  
Radiographic Images ◽  
X Ray ◽  
Male Predominance ◽  
Mother And Child ◽  
Chest X Ray ◽  
The Right ◽  
The University ◽  
Tuberculosis In Children

Background: The etiological diagnosis of pneumonia is often difficult because of the impossibility of microbiological confirmation most of the time. Therefore, chest X-ray is still essential for a positive diagnosis and etiological orientation. The main objective of our study was to describe the radiographic aspects of acute community-acquired pneumonia and tubercular pneumonia in children.Methods: This was a descriptive retrospective study conducted at the university hospital mother and child of Tsaralalana from January 1st to July 31st, 2017.Results: Sixty-nine cases of pneumonia were included, including 13 cases of TB pneumonia and 46 cases of acute community-acquired pneumonia. The average age was 36.68 months with a male predominance. Clinically, respiratory functional signs predominated in both cases. Alteration in general condition was mainly observed in tubercular pneumonia (26.08%). Alveolar syndromes were present in 43.47% of TB pneumonias and 36.94% of acute community-acquired pneumonia. With regard to the radiographic images, alveolar involvement was common to both types of pneumonia; the nodular image was present in 8.69% of the tubercular pneumonias and 2.17% of the acute community-acquired pneumonia; the cavity image was present only in the tubercular pneumonia (p=0.04); the right-sided location predominated in both cases.Conclusions: X-ray images were common to both TB pneumonia and acute community-acquired pneumonia; some images were specific to TB pneumonia. However, the etiologic orientation of pneumonia is based on a combination of epidemiologic, clinical, and radiographic evidence.

The Uptake and Distribution of Potassium in Roots of Duckweed (Lemna Minor L) As Measured using Low Temperature X-Ray Microanalysis

1982 ◽  
Vol 40 ◽  
pp. 408-411
Author(s):  
Patrick Echlin ◽  
Clifford Lai ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Background Subtraction ◽  
Cell Walls ◽  
Lemna Minor ◽  
Beam Current ◽  
X Ray ◽  
Dark Regime ◽  
Low Temperature Microscopy

Lemna minor L. plants were grown in a 14 H light and 10 H dark regime at 298 K in a medium containing 2 mM [K+]. Roots, 20 mm long and photosynthetically active, were removed and prepared for low temperature microscopy using methods described elsewhere. Fracture faces were made using the AMRAY Biochamber and the analysis carried out using an AMRAY 1000A SEM fitted with an LaB6 gun and a Kevex Si (Li) x-ray detector at 15-17 kV and a beam current of 1-2 nA. A reduced raster (1.0 μm2) was placed at the centre of the cell being analysed, care being taken to avoid any contact with the cell walls. Samples were maintained at 100-110 K throughout analysis and an LN2 cooled anti-contamination device was inserted close to the specimen. The spectra were analysed using the peak/background (P/B) ratio technique following use of background subtraction and peak de-convolution routines. Between eight and twelve fracture faces were analysed for each of the ten sites along the length of the root and the data pooled and presented in Table I.

The Early Years of X-Ray Diffraction and X-Ray Spectrometry

1995 ◽  
Vol 39 ◽  
pp. 1-11
Author(s):  
J. L. de Vries
Keyword(s):  
The Netherlands ◽  
Early Years ◽  
X Ray Diffraction ◽  
Parental Home ◽  
Only Child ◽  
Technical School ◽  
X Ray ◽  
The Family ◽  
The Right ◽  
The University

Wilhelm Conrad Röntgen was born on 27-03-1845, 150 years ago, in Lennep- Remscheid in Westphalen, Germany, from a German father and a Dutch mother. He remained an only child. When he was 3 years old, the family moved to Apeldoom in the Netherlands. His parental home exists and will be the Röntgen bar. After going to school in Apeldoorn, he went to a technical school in Utrecht, where he finished in 1865. He enrolled in the University of Utrecht in the Netherlands, but found that he did not have the right certificates to pass the examinations. He then went to Zurich to the newly stifted Eidgenössische Technische Hochschule, where restrictions were less severe. In 18869, he got his doctorate on ‘Thermodynamics of gases.’ He was a brilliant student with a wide variety of interests.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe

1990 ◽  
Vol 48 (2) ◽  
pp. 314-315
Author(s):  
K.K. Soni ◽  
D.B. Williams ◽  
J.M. Chabala ◽  
R. Levi-Setti ◽  
D.E. Newbury
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Equilibrium Phase ◽  
Icosahedral Symmetry ◽  
Ion Microprobe ◽  
X Ray ◽  
Cu Alloys ◽  
Two Phases ◽  
The University ◽  
Secondary Ion

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.

Discovery of intracellular 2,8 dihydroxyadenine crystals in bovine lymphatic and hepatic cells

1987 ◽  
Vol 45 ◽  
pp. 906-907
Author(s):  
W. E. Rigsby ◽  
D. M. Hinton ◽  
V. J. Hurst ◽  
P. C. McCaskey
Keyword(s):  
Polarized Light ◽  
Paraffin Sections ◽  
Tissue Samples ◽  
Whole Cells ◽  
Tissue Sections ◽  
Hepatic Cells ◽  
Slaughter House ◽  
Mammalian Tissues ◽  
Carbon Coated ◽  
Cellular Components

Crystalline intracellular inclusions are rarely seen in mammalian tissues and are often difficult to positively identify. Lymph node and liver tissue samples were obtained from two cows which had been rejected at the slaughter house due to the abnormal appearance of these organs in the animals. The samples were fixed in formaldehyde and some of the fixed material was embedded in paraffin. Examination of the paraffin sections with polarized light microscopy revealed the presence of numerous crystals in both hepatic and lymph tissue sections. Tissue sections were then deparaffinized in xylene, mounted, carbon coated, and examined in a Phillips 505T SEM equipped with a Tracor Northern X-ray Energy Dispersive Spectroscopy (EDS) system. Crystals were obscured by cellular components and membranes so that EDS spectra were only obtainable from whole cells. Tissue samples which had been fixed but not paraffin-embedded were dehydrated, embedded in Spurrs plastic, and sectioned.

Pyrotechnic Residues in Gunshot Residue Analysis

1985 ◽  
Vol 43 ◽  
pp. 128-129
Author(s):  
H. M. Sagara ◽  
S. A. Schliebe ◽  
M. C. Kong
Keyword(s):  
Law Enforcement ◽  
Residue Analysis ◽  
Gunshot Residue ◽  
Particle Analysis ◽  
Dry Skin ◽  
X Ray ◽  
Skin Cells ◽  
Smokeless Powder ◽  
Carbon Coated ◽  
Detailed List

Particle analysis by scanning electron microscopy with energy-dispersive x- ray analysis is one of the current methods used in crime laboratories to aid law enforcement in identifying individuals who have recently fired or handled a firearm. During the discharge of a firearm, the high pressure caused by the detonation of the cartridge materials forces a portion of the generated gases through leaks in the firing mechanism of the weapon. These gases contain residues of smokeless powder, primer mixture, and contributions from the projectile itself. The condensation of these hot gases form discrete, micrometer-sized particles, which can be collected, along with dry skin cells, salts, and other hand debris, from the hands of a shooter by a simple adhesive lift technique. The examination of the carbon-coated adhesive lifts consist of time consuming systematic searches for high contrast particles of spherical morphology with the characteristic elemental composition of antimony, barium and lead. A detailed list of the elemental compositions which match the criteria for gunshot residue are discussed in the Aerospace report.

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