Life Sciences Commons^™

Vascular Changes In Popliteal Lymph Nodes Due To Antigen Challenge In Normal And Lethally Irradiated Mice, Douglas A. Steeber, Chris M. Erickson, Kees C. Hodde, Ralph M. Albrecht

Scanning Microscopy

The microvascular system of the murine popliteal lymph node was investigated using scanning electron microscopy of microcorrosion casts. Time-dependent changes in the microvasculature following regional antigen challenge in normal and lymphocyte-depleted mice were studied. Normal lymph node microvasculature exhibited a significant increase in both the vascular bed and post-capillary venules containing high-endothelium in response to antigen challenge. Lymph nodes of lymphocyte-depleted mice showed no microvascular size increase following antigen challenge and a reduction in the amount of high-endothelium was observed.

Theory Of Electron Beam Induced Current And Cathodoluminescence Contrasts From Structural Defects Of Semiconductor Crystals; Steady-State And Time-Resolved Problems, A. Jakubowicz

Scanning Microscopy

Electron-beam-induced current and cathodoluminescence are powerful tools for revealing and characterizing point-like defects, dislocations, and grain boundaries in semiconductor crystals.

This paper reviews the theoretical studies of electron-beam-induced current and cathodoluminescence contrasts from local structure defects of semiconductor crystals (the geometrical aspects of both contrasts, the assessment of the defect properties from the contrast, the evaluation of bulk parameters in the presence of defects, and time-resolved characterization of defects), including recent developments in this area.

The Effect Of Controlled Diffusion Of Ions On The Formation Of Hydrated Calcium Oxalate Crystals, H. Lachance, R. Tawashi

Scanning Microscopy

Calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD) and calcium oxalate trihydrate (COT) were grown from solutions under controlled release of the reacting ions. The mass transfer kinetics of ions released from an insoluble polyethylene matrix, from an osmotic pump system and from the hydrolysis of diethyl oxalate were studied under different experimental conditions. It was possible with simple laboratory techniques to grow well-formed crystals of COM, COD and COT, suitable for single crystal work. Results obtained show that the degree of hydration, size, and morphology of the crystals formed, are controlled by interfacial kinetic factors.

Electron Energy Loss Spectroscopy And Biology, C. Jeanguillaume

Scanning Microscopy

Although most of the recent work concerning EELS in electron microscopy is related to instrumental developments, there are a number of papers relating to biological applications. The aim of this paper is to attempt to present in a pedagogical manner the subject of EELS and biology. The biologist will be taught about EELS and the physicist about the possible biological applications of this technique. The paper thus consists of: 1) a presentation of a minimum background on EELS required for biologists to realize what its potential is; 2) a description of why EELS is a useful tool in biology; 3) …

Correlative Light And Electron Microscopy Of Platelet Adhesion And Fibrinogen Receptor Expression Using Colloidal-Gold Labeling, Steven L. Goodman, Ralph M. Albrecht

Scanning Microscopy

Differences in the shape change responses of platelets to various polymers may determine the thrombotic potential of these materials. Substrate-dependent variation in the expression and motility of the platelet fibrinogen receptor may underlie these differences due to this ligand's essential role in platelet aggregation. In this study we examine platelet activation on polyetherurethaneureas (PEUUs) presently being evaulated for vascular prosthetic applications. These polymers are prepared as 50-100nm thin films suitable as substrates for consecutive light microscopy, high voltage electron microscopy (HVEM), and SEM. 18nm colloidal gold coupled to fibrinogen permits visualization of that receptor's motility in living cells by video-enhanced …

Immuno-Scanning Electron Microscopy Of Normal And Leukemic Leukocytes Labeled With Colloidal Gold, D. Soligo, G. Lambertenghi-Deliliers, E. De Harven

Scanning Microscopy

The immunogold method, utilizing 40 nm colloidal gold particles which can be selectively visualized with the scanning electron microscope (SEM) in the backscattered electron imaging mode was used for the study of blood cells incubated with various monoclonal antibodies. Numerous antileukocyte monoclonal antibodies still recognize lightly glutaraldehyde prefixed antigens and can be used to identify various blood cell types and even to recognize their different maturation stages.

Clearcut differences in surface morphology exist among peripheral blood normal leukocytes and even among the principal lymphocyte subclasses. Marked heterogeneity in surface morphology is, on the other hand, evident when studying precursors or …

The Application Of Micro-Raman Spectroscopy To Analysis And Identification Of Minerals In Thin Section, H. Mao, R. J. Hemley, E. C. T. Chao

Scanning Microscopy

Micro-Raman spectroscopy is a useful analytical tool for studying minerals in thin section. The advantages of this technique as a structural probe for analysis of micron-size minerals are demonstrated with a study of polymorphism of SiO₂ and MgSiO₃. Three polymorphs of silica, 𝝰-quartz, coesite, and glass, in a thin section of Coconino sandstone were identified in situ with a Raman microprobe. The Raman spectra of these phases were compared to that measured for stishovite obtained from the same rock. Spectra of protoenstatite, orthoenstatite, and clinoenstatite, three polymorphs of MgSiO₃, are consistent with their similar pyroxene …

The Cytotoxic Effects Of Trimethylpentane On Rat Renal Tissue, William N. Norton, David R. Mattie

Scanning Microscopy

The primary objective of the investigation was to determine the acute cytopathologic effects of 2,3,4 -trimethylpentane, a major constituent of gasoline, on renal tissue of the mature male rat. Three groups of 9 Fischer-344 rats each were administered trimethylpentane by gavage twice weekly for 7, 14, or 28 days at a concentration of 1.5 ml/kg body weight. The tissues were fixed by perfusion, and subsequently processed for scanning and transmission electron microscopy. Al though the manifestations of hydrocarbon toxicity were evident in all experimental tissues examined, the extent and magnitude of cellular lesions increased as the exposure period progressed. The …