ESEM

The materials used in the decoration of three painted astragaloi (knucklebones) from the Koroneia cave (Greece) were investigated by means of sequential application of non-destructive and destructive techniques: optical microscopy, environmental scanning electron microscopy coupled with X-ray microanalysis (ESEM–EDX), Fourier transform infrared spectroscopy (FTIR) with micro-attenuated total reflection (μ-ATR) technique, high performance liquid chromatography (HPLC) coupled with UV-fluorescence and gas chromatography–mass spectrometry (GC–MS) were used.The main results highlighted that the three astragaloi were prepared with a ground of ochre or iron clay and painted with a proteinaceous matter such as binder egg tempera. Both FTIR and GC–MS agree in the detection of lipids that can be related to egg. Organic dyestuffs identified as madder lake and shellfish purple were used together with inorganic pigments.

Nanotechnology, which deals with features as small as a 1 billionth of a meter, began to enter into mainstream physical sciences and engineering some 20 years ago. Recent applications of nanoscience include the use of nanoscale materials in electronics, catalysis, and biomedical research. Among these applications, strong interest has been shown to biological processes such as blood coagulation control and multimodal bioimaging, which has brought about a new and exciting research field called nanobiotechnology. Biotechnology, which itself also dates back ∼30 years, involves the manipulation of macroscopic biological systems such as cells and mice in order to understand why and how molecular level mechanisms affect specific biological functions, e.g., the role of APP (amyloid precursor protein) in Alzheimer’s disease (AD). This review aims (1) to introduce key concepts and materials from nanotechnology to a non-physical sciences community; (2) to introduce several state-of-the-art examples of current nanotechnology that were either constructed for use in biological systems or that can, in time, be utilized for biomedical research; (3) to provide recent excerpts in nanotoxicology and multifunctional nanoparticle systems (MFNPSs); and (4) to propose areas in neuroscience that may benefit from research at the interface of neurobiologically important systems and nanostructured materials.

Observations of sodium sulfate hydration, dehydration, dissolution and crystallization at magnifications of 200-10,000x have revealed previously undescribed material behaviors that help explain the destructive effects of this salt in wall paintings, historic structures and monuments. Experiments performed in the environmental scanning electron microscope show that large crystals of anhydrous sodium sulfate, when exposed to water vapor, initially form a skin of sodium sulfate decahydrate that prevents the complete hydration of the crystal until sufficient liquid water is present to dissolve the skin. Hydration of sodium sulfate is also initially much slower than dehydration during similar rates of humidity change. Sodium sulfate decahydrate consistently breaks down during dehydration to form sub-micron aggregates of anhydrous sodium sulfate. Provided that the decahydrate form is not dissolved by excess liquid water, subsequent hydration-dehydration cycles result in a highly porous, high-surface area salt structure consisting of sub-micron particles. Once this porous sodium sulfate structure is established, hydration and dehydration occur at roughly the same rate. Dissolution of the fine-grained structure by liquid water, followed by drying, results in the rapid crystallization of much larger (10-100µm) sodium sulfate decahydrate crystals with well-defined crystal faces.

The materials used in the decoration of three painted astragaloi (knucklebones) from the Koroneia cave (Greece) were investigated by means of sequential application of non-destructive and destructive techniques: optical microscopy, environmental scanning electron microscopy coupled with X-ray microanalysis (ESEM–EDX), Fourier transform infrared spectroscopy (FTIR) with micro-attenuated total reflection (μ-ATR) technique, high performance liquid chromatography (HPLC) coupled with UV-fluorescence and gas chromatography–mass spectrometry (GC–MS) were used.The main results highlighted that the three astragaloi were prepared with a ground of ochre or iron clay and painted with a proteinaceous matter such as binder egg tempera. Both FTIR and GC–MS agree in the detection of lipids that can be related to egg. Organic dyestuffs identified as madder lake and shellfish purple were used together with inorganic pigments.

The observation of asphalt binder microstructure with the Environmental Scanning Electron Microscope (ESEM) has yielded promising results. There have been findings that show the microstructure evolving with aging and certain loading applications. The goal of this study was to observe the PMA microstructure using ESEM analysis. Four PMA binders of varying PG grades were observed in ESEM, comparing them to a straight run binder. The binders were compared in terms of the fibril diameter and shape observed visually, along with the fibril structure. The initial ‘bee’ structures before the appearance of the fibrils were also compared. It was found that the PMA binders had a denser fibril structure, corresponding to their higher PG grades indicating stiffer binders, although this varied with different PMAs. The images were also analyzed by calculating the area and length of the fibrils through an image analysis protocol. This study is a step towards the further understanding of the microstructure of PMAs.

Modern cell biology is reliant on light and fluorescence microscopy for analysis of cells, tissues and protein localisation. However, these powerful techniques are ultimately limited in resolution by the wavelength of light. Electron microscopes offer much greater resolution due to the shorter effective wavelength of electrons, allowing direct imaging of sub-cellular architecture. The harsh environment of the electron microscope chamber and the properties of the electron beam have led to complex chemical and mechanical preparation techniques, which distance biological samples from their native state and complicate data interpretation. Here we describe recent advances in sample preparation and instrumentation, which push the boundaries of high-resolution imaging. Cryopreparation, cryoelectron microscopy and environmental scanning electron microscopy strive to image samples in near native state. Advances in correlative microscopy and markers enable high-resolution localisation of proteins. Innovation in microscope design has pushed the boundaries of resolution to atomic scale, whilst automatic acquisition of high-resolution electron microscopy data through large volumes is finally able to place ultrastructure in biological context.

We have developed two integrated thermocouple (TC) crucible systems that allow precise measurement of sample temperature when using a furnace associated with an environmental scanning electron microscope (ESEM). Sample temperatures measured with these systems are precise (±5°C) and reliable. The TC crucible systems allow working with solids and liquids (silicate melts or ionic liquids), independent of the gas composition and pressure. These sample holder designs will allow end users to perform experiments at high temperature in the ESEM chamber with high precision control of the sample temperature.

Concrete with adequately soaring compressive strength has been in use for building skyscrapers, pavements, two-dimensional elements like plates and slab-decks, threedimensional solid masses like retaining walls and dams. However, majority of these structural elements continue to be brittle in nature. Generally, the compressive strength is directly proportional to brittleness. This creates prospective restrictions on the use of high strength concrete. A high stress concentration at junctions of concrete and steel is not uncommon that may cause a fracture of the concrete. Therefore, use of high ductile concrete becomes necessary for increasing the durability of the concrete structures. This paper focuses on development of Crack-free and High Ductile bendable concrete which has a tensile strain capacity of 1.67 percent for a Polyvinyl Alcohol fiber content of 2.0 percent by volume of concrete and the specimens revealed microcracks less than 153µm when subjected to Uniaxial test. Various transport properties like Rapid Chloride Penetration, Sorptivity, and Permeability of Bendable Concrete at the age of 28 days are also studied

Spurious x-ray signals, which previously prevented high-resolution energy-dispersive x-ray analysis (EDS) in the environmental scanning electron microscope (ESEM), can be corrected using a simple method presented here. As the primary electron beam travels through the gas in the ESEM chamber, a significant fraction of the primary electrons is scattered during collisions with gas molecules. These scattered electrons form a broad skirt that surrounds the primary electron beam as it impacts the sample. The correction method assumes that changes in the width of the electron skirt with pressure are less important than changes in the skirt intensity; this method works as follows: The influence of the gas on the overall x-ray data is determined by acquiring EDS spectra at two pressures. Subtracting the two spectra provides us with a difference spectrum which is then used to correct the original data, using extrapolation, back to the x-ray spectrum expected under high-vacuum conditions. Low-noise data are required to resolve small spectral peaks; however, the principle should apply equally to x-ray maps and even to low-magnification images.

El siguiente ensayo hace una reflexión respecto a las condiciones actuales que vive el país y la posibilidad de instauración de un modelo de economía social de mercado en el contexto de una serie de reformas políticas, sociales y económicas que buscan lograr un nuevo modelo de desarrollo para el país.

Energy saving estimation model (ESEM) use normal distribution (Gaussian) probability theory to predict potential savings for previously determined system improvements. Those improvements are low/high cost investments based on data gathered during one year monitoring of typical hypermarket facility HVAC system. The consumption of electrical energy and natural gas has been monitored and system segments with largest amount of energy consumption have been marked. Gathered data pointed out to fan units as the biggest energy consumers and suggested that system energy-saving improvement must be focused on fans energy consumption control. This paper deals with ESEM inputs and outputs in order to provide correct financial estimation of specific investment.

The use of cyclodextrins (CDs) for controlled delivery of drugs is largely presented in the literature. However, the question of whether CDs themselves linked to a polymeric network are able to sustain the release of drugs still persists. Here, CD immobilization within dextran microspheres is reported, and CD-dextran complexes were packed in a glass column and then, the retention time of different drugs and drug model compounds was determined by liquid chromatography. The release profiles of drugs and of drug model compounds (indole, 3-nitrophenol, p-hydroxybenzoic acid, diclofenac), characterized by different values of the retention time (high, moderate or low), were investigated. The release rates were quite high even for drugs that exhibit very high retention time (high association equilibrium constant). Moreover, the volume of the release fluid strongly influences the rate of drug release. As a whole, "the sink conditions" must be continuously maintained, since at each...

Abstract. Realism, resolution, and portrayal of spatial relationships are three conditions for iconic representations in formal taxonomic descriptions. Hand drawing is a painstaking and time-consuming technique. The environmental scanning electron microscope (ESEM) is an alternative that can provide detailed images without damaging the specimen, thus allowing it to be used for further study either in light microscopy or molecular analysis. In this work, we evaluate the suitability of ESEM for basic taxonomic study with specimens of two arthropods groups: water mites and bathynelids. The ESEM provides enough resolution to classify even to the species level. Different kinds of curatorial adhesive strips were used with satisfactory results. We foresee that the ESEM will be a common taxonomic tool in the near future.

Novel modifications of an environmental scanning electron microscope (ESEM) were made in order to measure the local deformations in drying cement paste. These nondestructively determined moisture-induced plane strains, obtained in 1 mm thick cement paste samples, are orthotropic. They vary with variations of relative humidity between 70%-80% and 40%-50%, being the highest at 20% RH. Both drying shrinkage and expansion of cement paste microstructure occur in early-age and mature samples. Microcracking due to moisture gradient could not be avoided, although very thin samples were examined with gradual reduction of relative humidity in drying steps of 10%. The coefficient of deformation of cement paste is directly proportional to shrinkage/expansion. It depends on variations of relative humidity during drying in ESEM and the sample age.

The newer generation of environmental scanning electron microscopes (ESEMs) allows samples to be viewed under a range of different vacuum conditions. No specific sample preparation protocols are required with the ESEMs, as fresh, unfixed samples are used and discarded later. We have worked out a method that preserves aerial hyphae on biltong that closely resemble fresh specimens and may be stored for viewing at a later date. Another advantage is that fixed samples are more resilient to the variable vacuum encountered in the ESEM. When biltong samples with fungal growth were first studied, we observed that vacuum-related artifacts were induced unless vacuum conditions and changes in pressure were carefully controlled. Damage readily occured in conidia and its delicate hyphae. Fresh, unfixed samples are very vulnerable to these artifacts. In addition, biltong proved to be a problematic study sample because of its high salt content, its hygroscopic nature as well as being laden with spices. To eliminate these artifacts, the preservation of specimens by OsO4 vapor fixation combined with a special sputter-coating technique is described. Previous studies confirmed that OsO4 vapor fixation is superior to traditional immersion fixation methods for the examination of hyphae and conidia of various fungi in a conventional SEM. However, both preparation methods induce sample shrinkage. We observed that OsO4 vapor fixation followed by Au coating under strictly controlled vacuum conditions induced fewer artifacts and gave the best images with minimum distortion in low pressure (LP) mode. The proposed method allows samples to be viewed both in ESEM and LP mode. There are however some disadvantages inherent to ESEM mode. Even when viewing fixed, coated samples, care should be taken to maintain a pressure of not lower than 0.2 Torr in the specimen chamber. It is critical that different samples have the same vacuum exposure history, as shrinkage and collapse were found to be directly related to the lowest pressure the samples were subjected to, both in the sputter coater chamber and in the electron microscope specimen chamber. Microsc. Res. Tech. 67:265–270, 2005. © 2005 Wiley-Liss, Inc.

We performed single pulses current measurement on single cells using dual nanoprobe through environmental scanning electron microscope nanomanipulator system. The ability to characterize the electrical property of single cells can be used as a novel method for cell viability detection in quantitative and instantaneous manners. The nanoprobe was successfully fabricated using focused ion beam tungsten deposition and etching processes. The characteristics of the nanoprobe were examined from the energy dispersion spectrometry and noise analyses. In this paper, for the first time, the electrical property of single cells under their native condition was presented. In order to apply this method for cell viability detection, two types of cells were used, i.e., dead cells and live cells. The results showed that there is a significant difference on the electrical measurement data between dead and live cells.