scholarly journals Dehydration and stabilization of unconsolidated laminated lake sediments using gypsum for the preparation of thin sections

2020 ◽  
Vol 12 (1) ◽  
pp. 1486-1496
Author(s):  
Ramachandran Dhavamani ◽  
Golej Marián ◽  
Starek Dušan ◽  
Pipík Radovan
Keyword(s):  
Lake Sediments ◽  
Room Temperature ◽  
Methodological Approach ◽  
Important Change ◽  
Thin Sections ◽  
Laminated Sediment ◽  
Change Concerns

AbstractAn improved Lamoureux method for subsampling of unconsolidated laminated sediment is described. Here, we describe a new methodological approach that changes the Lamoureux method in four steps of which the most important change concerns dehydration and stabilization. In this step, we adopted gypsum embedding of the subsample, which took about 1 h to harden and keeps the sediment partially moist. After drying of the gypsum, the subsamples are impregnated with Epoxy 2000 resin under room temperature. This method requires commonly available equipment and can be implemented cost-effectively within 3–4 days.

Lattice imaging and pore structure of β ferric oxyhydroxide

1978 ◽  
Vol 36 (1) ◽  
pp. 264-265
Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bulk Material ◽  
Model Structure ◽  
Bulk Crystals ◽  
Lattice Imaging ◽  
Thin Sections ◽  
Ferric Oxyhydroxide ◽  
Resolution Electron ◽  
Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

Immunogold localization of HMB-45 antigen in pulmonary lymphangiomyomatosis

1995 ◽  
Vol 53 ◽  
pp. 998-999
Author(s):  
J.M. Minda ◽  
E. Dessy ◽  
G. G. Pietra
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Muscle Cells ◽  
Ultrastructural Localization ◽  
Reproductive Age ◽  
Thin Sections ◽  
Smooth Muscle Proliferation ◽  
Hmb 45

Pulmonary lymphangiomyomatosis (PLAM) is a rare disease occurring exclusively in women of reproductive age. It involves the lungs, lymph nodes and lymphatic ducts. In the lungs, it is characterized by the proliferation of smooth muscle cells around lymphatics in the bronchovascular bundles, lobular septa and pleura The nature of smooth muscle proliferation in PLAM is still unclear. Recently, reactivity of the smooth muscle cells for HMB-45, a melanoma-related antigen has been reported by immunohistochemistry. The purpose of this study was the ultrastructural localization of HMB-45 immunoreactivity in these cells using gold-labeled antibodies.Lung tissue from three cases of PLAM, referred to our Institution for lung transplantation, was embedded in either Poly/Bed 812 post-fixed in 1% osmium tetroxide, or in LR White, without osmication. For the immunogold technique, thin sections were placed on Nickel grids and incubated with affinity purified, monoclonal anti-melanoma antibody HMB-45 (1:1) (Enzo Diag. Co) overnight at 4°C. After extensive washing with PBS, grids were treated with Goat-anti-mouse-IgG-Gold (5nm) (1:10) (Amersham Life Sci) for 1 hour, at room temperature.

Observations of thick and thin sections in a field-emission SEM

1994 ◽  
Vol 52 ◽  
pp. 1018-1019
Author(s):  
W. P. Wergin ◽  
S. Roy ◽  
E. F. Erbe ◽  
C. A. Murphy ◽  
C. D. Pooley
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.

scholarly journals LOCALIZATION OF MACROMOLECULES IN ESCHERICHIA COLI

1961 ◽  
Vol 9 (3) ◽  
pp. 539-553 ◽  
Author(s):  
Lucien G. Caro
Keyword(s):  
Escherichia Coli ◽  
Poisson Distribution ◽  
Cross Sections ◽  
Morphological Changes ◽  
Nuclear Region ◽  
High Concentration ◽  
Short Pulses ◽  
Thin Sections ◽  
Change Concerns ◽  
Very Short Pulses

If thin sections of Escherichia coli, labeled uniformly with tritium, are radioautographed calculations, based on the distribution of section sizes show that the number of H3 decays per section should be very close to a Poisson distribution. We might, therefore, expect that the distribution of radioautographic grain counts among random cross-sections should follow a Poisson distribution. It can then be inferred that a deviation from a Poisson indicates a high concentration of label in a preferred region. This region can then be identified by analysis of serial section and comparison with electron micrographs. Sections of cells labeled with leucine-H3 gave a Poisson distribution of grain counts, and it was concluded that proteins were distributed fairly uniformly throughout the cell. The situation was not changed if labeled cells were placed in chloramphenicol or if very short pulses of label were used. When Escherichia coli is grown in presence of chloramphenicol a major morphological change concerns the nuclear region: it becomes more regular in outline, nearly spherical, and occupies a smaller proportion of the cell length. The previously described association between DNA labeled with thymidine-H3 and the nuclear region was confirmed by showing that the distribution of the label in the cell followed exactly the morphological changes of the nuclear region. It was also shown that the concentration of DNA in the nuclear region was at least 45 times higher than that of the cytoplasm. Several morphological features of cells grown in chloramphenicol and examined in the electron microscope are discussed.

A novel methodological approach for thin-section description and its application to periglacially disturbed Pleistocene deposits from Danbury, Essex, UK

2011 ◽  
Vol 90 (4) ◽  
pp. 271-291 ◽  
Author(s):  
K. Leszczynska ◽  
J. Boreham ◽  
S. Boreham
Keyword(s):  
Thin Section ◽  
Systematic Approach ◽  
Methodological Approach ◽  
Main Process ◽  
Freezing And Thawing ◽  
Quaternary Deposits ◽  
Thin Sections ◽  
New Approach ◽  
C 50 ◽  
New Hypothesis

AbstractAlthough micromorphological terminology has been evolving since 1960, there have been few attempts to create a systematic approach to the description of thin-sections which would serve as a guiding tool for inexperienced researchers, students, and all new to the field of micromorphology. In this paper we present a novel, decision tree based systematic approach for thin-section description. This new approach attempts to unify micromorphological descriptions of Quaternary deposits, regardless of the character of the deposit and the purpose of the analysis.In this research project, named ‘Hidden Ice Worlds’, the micromorphology of an 8 m thick sequence of periglacially disturbed deposits from the Royal Oak Pit, Danbury hill, Essex, UK is described. This sequence is situated on the eastern side of Danbury hill, at c. 50 m OD. Based on micromorphological analyses, a new hypothesis for the evolution of this sequence is presented. Multiple phases of physical reworking associated with freezing and thawing of the deposit, subsequent to Elsterian (Anglian) glaciation (480-420 ka BP) is proposed as the main process responsible for the evolution of the sequence. As periglacially derived deposits are usually removed from such elevated locations on hill' slopes, inversion of the topography is proposed as a necessary factor for the formation and preservation of the sequence described in this atypical location.

Tephra anchored floating varve chronology covering ca. 19.0-11.0 ka BP in new core from Lake Lago Grande di Monticchio: preliminary results

2020 ◽  
Author(s):  
Xueru Zhao ◽  
Sabine Wulf ◽  
Markus J. Schwab ◽  
Rik Tjallingii ◽  
Achim Brauer
Keyword(s):  
High Resolution ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Methodological Approach ◽  
Radiocarbon Dates ◽  
Thin Sections ◽  
Last Glacial ◽  
Varve Chronology ◽  
Varve Counting ◽  
The Last Glacial

<p>The high-resolution Monticchio (MON) sediment record has been demonstrated to be a key archive for reconstructing climate and environmental changes in the central Mediterranean for the last glacial-interglacial cycle. New sediment cores have been retrieved in April 2016 to investigate particularly the transition from the Last Glacial Maximum into the Holocene with a new high-resolution methodological approach. A floating varve chronology spanning ca. 8,000 years has been established by varve counting on thin sections using a petrographic microscope and layer thickness based sedimentation rate estimates for non- or poorly varved intervals. Varve counting is based on detailed seasonal deposition models of five different varve types. The resulting floating chronology consist of 66.6% individually counted varves and 33.4% interpolated years. The uncertainty estimate of the floating chronology has been determined by double counting and amounts to ±5.8%.</p><p>The floating chronology is anchored to an absolute chronology using the Agnano Pomici Principali tephra, dated at 11,999±52 cal yrs BP from paleosols overlying proximal tephra (Bronk Ramsey et al. 2015), is a suitable anchoring point to cross correlation. The resulting varve-based chronology has been compared with several other marker tephras dated elsewhere including the Soccavo 4 tephra (11,700±150 cal yrs BP), the Neapolitan Yellow Tuff (NYT; 14,194±172 cal yrs BP) and the Greenish tephra (19226±104 cal yrs BP). Further comparison with published (Hajdas et al. 1997) and new radiocarbon dates from different terrestrial macro remains are discussed in this paper. This study presents an independent chronology for the last glacial/interglacial transition for a comparison of MON data with high-resolution lake records western and central Europe.</p><p>References</p><p>Bronk Ramsey, C., P. G. Albert, S. P. E. Blockley, M. Hardiman, R. A. Housley, C. S. Lane, S. Lee, I. P. Matthews, V. C. Smith & J. J. Lowe (2015) Improved age estimates for key Late Quaternary European tephra horizons in the RESET lattice. Quaternary Science Reviews, 118<strong>,</strong> 18-32.</p><p>Hajdas, I., G. Bonani, B. Zolitschka, A. Brauer & J. Negendank (1997) 14C Ages of Terrestrial Macrofossils from Lago Grande Di Monticchio (Italy). Radiocarbon, 40<strong>,</strong> 803-807.</p>

scholarly journals A Methodological Approach for Testing the Viability of Seeds Stored in Short-Term Seed Banks

2017 ◽  
Vol 9 (4) ◽  
pp. 563-570 ◽  
Author(s):  
Jose A. FORTE GIL ◽  
Lourdes YABOR ◽  
Antonio BELLIDO NADAL ◽  
Francisco COLLADO ◽  
Pablo FERRER-GALLEGO ◽  
...  
Keyword(s):  
Seed Bank ◽  
Salt Marshes ◽  
Room Temperature ◽  
Methodological Approach ◽  
Seed Banks ◽  
The Other ◽  
In Vitro Tests ◽  
Short Term ◽  
Natural Park ◽  
Short Period

Efficient management of ‘active’ seed banks – specifically aimed at the short-term storage at room temperature of seeds to be used locally in conservation/regeneration programmes of endemic or endangered plant species – requires establishing the optimal storage time to maintain high seed viability, for each stored species. In this work, germination of seeds of the halophytes Thalictrum maritimum, Centaurea dracunculifolia and Linum maritimum has been investigated. The seeds had been stored for different periods of time in the seed bank of ‘La Albufera’ Natural Park (Valencia, SE Spain) after collection in salt marshes of the Park, where small populations of the three species are present. Seeds of T. maritimum and C. dracunculifolia have a relatively short period of viability at room temperature, and should not be stored for more than three years. On the other hand, L. maritimum seeds maintain a high germination percentage and can be kept at room temperature for up to 10 years. T. maritimum seeds, in contrast to those of the other two species, did not germinate in in vitro tests nor when sown directly on a standard substrate, unless a pre-treatment of the seeds was applied, mechanical scarification being the most effective. These results will help to improve the management of the seed bank, to generate more efficiently new plants for reintroduction and reinforcement of populations of these species in their natural ecosystems within the Natural Park.

scholarly journals Rapid embedding of tissues in Lowicryl K4M for immunoelectron microscopy.

1984 ◽  
Vol 32 (11) ◽  
pp. 1217-1223 ◽  
Author(s):  
L G Altman ◽  
B G Schneider ◽  
D S Papermaster
Keyword(s):  
Room Temperature ◽  
Dimethyl Formamide ◽  
Point Counting ◽  
Rabbit Antibody ◽  
Electron Microscope Level ◽  
Thin Sections ◽  
Kidney Microsomes ◽  
Embedding Medium ◽  
Lowicryl K4m ◽  
Accelerated Protocol

Lowicryl K4M (K4M) was recently introduced as an embedding medium for immunocytochemistry at the electron microscope level (BL Armbruster, E Carlemalm, R Chiovetti, RM Garavito, JA Hobot, E Kellenberger, W Villiger (1982):J Microsc 126:77 and E Carlemalm, M Garavito, W Villiger (1982):J Microsc 126:123). While earlier protocols of fixation and embedding required 4-6 days, the present method has reduced the processing time by accelerating both dehydration of tissues and polymerization of K4M so that tissues can be prepared for sectioning within 4 hr. The immunocytochemical labeling density was quantitated in order to determine relative antigen preservation in tissues embedded by the accelerated protocol as compared to slower K4M embedding techniques and to tissues embedded in glutaraldehyde-cross-linked bovine serum albumin (BSA). Thin sections of Bufo marinus kidney were labeled with rabbit antibody to Na+,K+ATPase alpha chain catalytic subunit isolated from B. marinus kidney microsomes (M Girardet, K Geering, JM Frantes, D Geser, BC Rossier, JP Kraehenbuhl, C Bron (1981):Biochemistry 20:6684). B. marinus retinas were labeled with rabbit anti-opsin. After fixation in paraformaldehyde(3%)-glutaraldehyde(3%), tissues were washed in buffer, dehydrated in 50, 75, and 90% dimethyl-formamide (DMF, 10 min each); K4M:DMF, 1:2 (15 min); K4M:DMF, 1:1, (20 min); K4M (25 min); K4M (30 min) at room temperature and transferred in fresh K4M to BEEM capsules for exposure to ultraviolet light (GE 15 watt, Black-lite, 10 cm, 45 min or less) at 4 degrees C. Thin sections were labeled successively with antibody, biotinylated sheep anti-rabbit F(ab')2 and avidin-ferritin. Ferritin labeling densities were determined by point counting. High labeling densities were observed with both antibodies, equaling or exceeding levels of labeling by slower protocols or embedment in BSA.

scholarly journals Thin Sectioning and Surface Replication of Ice at Low Temperature

1984 ◽  
Vol 30 (105) ◽  
pp. 248-250 ◽  
Author(s):  
Margaret A. Daley ◽  
Stephen H. Kirby
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Sample Material ◽  
Cyanoacrylate Glue ◽  
Thin Sections ◽  
Strong Bond ◽  
Thin Sectioning ◽  
Annealing Effects ◽  
A New Technique ◽  
Microstructural Studies

AbstractWe have developed a new technique for making thin sections and surface replicas of ice at temperatures well below 273 K. Cyanoacrylate glue forms a strong bond with ice and glass at 245 K, eliminating the need to fix the sample to the thin-section slide by melting and freezing. Surface replicas are made by melting away sample material once the glue has cured. Glue replicas are permanent and highly detailed, making them suitable for microstructural and textural studies at room temperature. Thin sections glued with cyanoacrylate glue are comparable in quality to melted-on sections. The ability to make thin sections without melting sample material is important in textural and microstructural studies of ice deformed at low temperatures because of annealing effects we have observed during conventional section making.

scholarly journals Scanning Magnetic Microscope Using A Hall-Effect Sensor for Images of Remanent Magnetization Fields

2019 ◽  
Author(s):  
Jefferson F. D. F. Araujo ◽  
Angela A. P. Correa ◽  
Elder Yokoyama ◽  
Andre L. A. dos Reis ◽  
Vanderlei C. Oliveira Jr. ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Spatial Resolution ◽  
Room Temperature ◽  
Rock Magnetism ◽  
Magnetization Distribution ◽  
Geological Samples ◽  
Thin Sections ◽  
Magnetic Carriers ◽  
Magnetic Microscopy

Scanning magnetic microscopy is a new tool that has recently been used to map magnetic fields with good spatial resolution and field sensitivity. This technology has great advantages over other instruments; for example, its operation does not require cryogenic technology, which reduces its operational cost and complexity. Here, we describe the construction of a customizing scanning magnetic microscope based on commercial Hall-effect sensors at room temperature that achieves a spatial resolution of 200 µm. Two scanning stages on the x- and y-axes of precision, consisting of two coupled actuators, control the position of the sample, and this microscope can operate inside or outside a magnetic shield. We obtained magnetic field sensitivities better than 521 nTrms/√Hz between 1 and 10 Hz, which correspond to a magnetic momentum sensitivity of 9.20 × 10–10 Am2. In order to demonstrate the capability of the microscopy, polished thin sections of geological samples, samples containing microparticles and magnetic nanoparticles were measured. For the geological samples, a theoretical model was adapted from the magnetic maps obtained by the equipment. Vector field maps are valuable tools for the magnetic interpretation of samples with a high spatial variability of magnetization. These maps can provide comprehensive information regarding the spatial distribution of magnetic carriers. In addition, this model may be useful for characterizing isolated areas over samples or investigating the spatial magnetization distribution of bulk samples at the micro and millimeter scales. As an auxiliary technique, a magnetic sweep map was created using Raman spectroscopy; this map allowed the verification of different minerals in the samples. This equipment can be useful for many applications that require samples that need to be mapped without a magnetic field at room temperature, including rock magnetism, the nondestructive testing of steel materials and the testing of biological samples. The equipment can not only be used in cutting-edge research but also serve as a teaching tool to introduce undergraduate, master's and Ph.D. students to the measurement methods and processing techniques used in scanning magnetic microscopy.

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