Standard Preparation Techniques Research Articles

A Novel Standard Sample Powder Preparation Method for Quantitative Analysis of Polymorphs

The purpose of this study was to improve the sensitivity and accuracy of the quantitative analysis of polymorphic mixtures. Calibration curve reliability has been improved through the advancement of standard mixture preparation techniques whereby samples at scales of several grams are homogeneously and accurately prepared without decrease in crystallinity. Crystalline powders are first micronized to anisotropic, nearly equal-sized (<10 μm) particles of almost random orientation in an air jet mill. These powders are then mixed in a vibration mill that includes rubber balls as mixing media. Using this technique, α and γ forms of indomethacin (IMC) were prepared in various proportions from 0.5% to 50% α content and subjected to X-ray powder diffraction analysis. The validation data showed that these precisely prepared standard mixtures resulted in superior analytical sensitivity and accuracy compared to those prepared by agate mortar. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association

Chemically Modified Glass Fiber as a Matrix-Free Reference Material for Volatile Compounds

Difficulties with obtaining suitable reference materials, which are applied for validation of analytical procedures and calibration of measured devices used in gaseous examinations (atmospheric air, indoor air, workplace atmosphere), are one of the most important challenges that stand in front of analytics. Known gaseous standard mixtures preparation techniques, both static and dynamic, are burdened with lots of inconveniences and disadvantages, which can be responsible for false analytical results. It appears that a very important step in the way of obtaining suitable reference materials useful in gaseous analysis is the technique of thermal decomposition of surface compounds. The paper describes a new type of matrix-free reference material-chemically modified glass fiber, which significantly makes it easier and simplifies the usage of reference materials produced using this technique.

A report on sample preparation at the ETH/PSI AMS facility in Zurich

This paper reports on the methods and results of sample preparation for 14C AMS measurements at the PSI/ETH facility in Zurich. Standard preparation techniques are described, which include chemical sample pretreatment and preparation of graphite targets. We report the results of measurements performed by our laboratory for the Fourth International Radiocarbon Inter-Comparison (FIRI).

A report on sample preparation at the ETH/PSI AMS facility in Zurich

This paper reports on the methods and results of sample preparation for 14 C AMS measurements at the PSI/ETH facility in Zurich. Standard preparation techniques are described, which include chemical sample pretreatment and preparation of graphite targets. We report the results of measurements performed by our laboratory for the Fourth International Radiocarbon Inter-Comparison (FIRI).

Clinical and Radiographic Evaluation of Root-canal Obturation with Obtura II

This study evaluated clinical and radiographic healing of 236 root-canal treatments in 131 cases obturated with the Obtura II system. One operator performed all canal preparation and obturation with sealer. A standardized apical-coronal preparation technique instrumented all canals. Clinical symptoms, periodontal condition, and radiographic findings were evaluated at 3, 6, and 12 months. Radiographs taken immediately postobturation were compared to recall radiographs. The level of the final root filling was classified as short (more than 2 mm short of the apex), flush (within 2 mm), or over (beyond) in 12.7%, 81.4%, and 5.9% of cases, respectively. More than 96% of cases were treated successfully by the Obtura II system. Where roots were filled flush, over, or short, lesions healed in 97%, 93%, and 93% of cases, respectively, with no significant differences (p < 0.05). Root filling excess had no impact on the healing process.

Separable balls around the maximally mixed multipartite quantum states

We show that for an m-partite quantum system, there is a ball of radius ${2}^{\ensuremath{-}(m/2\ensuremath{-}1)}$ in Frobenius norm, centered at the identity matrix, of separable (unentangled) positive semidefinite matrices. This can be used to derive an \ensuremath{\epsilon} below which mixtures of \ensuremath{\epsilon} of any density matrix with $1\ensuremath{-}\ensuremath{\epsilon}$ of the maximally mixed state will be separable. The \ensuremath{\epsilon} thus obtained is exponentially better (in the number of systems) than existing results. This gives a number of qubits below which nuclear magnetic resonance with standard pseudopure-state preparation techniques can access only unentangled states; with parameters realistic for current experiments, this is 23 qubits (compared to 13 qubits via earlier results). A ball of radius 1 is obtained for multipartite states separable over the reals.

Mechanical stress induced activity and phase composition changes in sulfated zirconia catalysts

Sulfated zirconia and Mn-promoted sulfated zirconia (0.5 and 2.0 wt% Mn) catalysts were subjected to mechanical stress. Pressing (10 min 540 MPa), milling (10 min vibrating mill), and grinding (manually, 10 min agate mortar) effected a partial phase transformation from the tetragonal to the monoclinic phase of ZrO 2. The mechanical stress also reduced the n-butane isomerization rate (1 kPa n-butane, 323–378 K, atmospheric pressure) to 30% and less of that measured for untreated catalyst. Standard sample preparation techniques for analytical methods thus alter the structural and catalytic properties of sulfated zirconia. Attempts to correlate data from different methods are futile unless the integrity of the sulfated zirconia is ensured.

Microstructural Indicators of Quality-related Characteristics of Blueberries—An Integrated Approach

Structure/function relationships associated with blueberry (Vaccinium corymbosum L.) fruit textural quality were studied using an approach which integrated microstructural, compositional and physical data. Microstructural preservation was optimized using standard and novel sample preparation techniques and equipment. A modified light microscopy (LM) technique most clearly illustrated differences among ‘Coville’, ‘Elliot’ and ‘Burlington’ highbush blueberry cultivars, in retention of flesh cell shape, cell wall integrity, degree of contact and amount of space between cells, and could account for storage life differences. Using the LM technique, parenchymal cell wall thickening in the flesh of ‘Burlington’ blueberries was observed in air stored fruit. The number and arrangement of flesh stone cells, and their cell wall thickness may also contribute to the firming effect observed. When berries lost water during storage, firming was reduced. Berry epidermal cells retained their integrity, and sub-epidermal cell walls appeared “corrugated”. The slight compression used to measure berry firmness caused separation between the sub-epidermal and flesh layers, while uncompressed berries showed no separation.An integrated approach can describe berry quality, aid in trait selection for breeding, and determine optimal storage conditions. Standard berry quality assessment methods may cause microstructural changes which could explain apparent inconsistencies in data.

Application of silicon substrates for high-Tc Josephson junctions and SQUIDs

We investigated the realization of YBCO Josephson junctions and SQUIDs on 10 x 10 mm 2 silicon bicrystal substrates and on 2 inch single crystalline silicon wafers. All buffer layers, YBCO films, passivation and metallization layers were deposited with the laser ablation technique. Bicrystal junctions with RSJ-like I-V characteristics, I C R N products of 150 μV at 77 K and microwave response up to the THz range were realized. DC-SQUIDs consisting of these junctions have working temperatures up to 80 K and transfer functions up to 30 μV/Φ 0 at 77 K. Further we enlarge our standard preparation technique of Josephson step-edge junctions on 5x10 mm 2 to 2 inch silicon wafers. YBCO films of this size have a critical temperature T C 87 K and critical current densities j C (77K) >3.10 6 A/cm 2 over the whole wafer area.

Rose bengal dye concentration and volume delivered via dye-impregnated paper strips.

The technique of administration and the resulting volume and concentration of the dye delivered to the eye via dye-impregnated paper strips are not standardized or known. The purpose of this study was to use a standard technique for preparation of rose bengal dye from commercially available paper strips to determine the variability in concentration based upon soak time, and to determine the volume delivered by such a technique to a model eye. Rose bengal filter paper strips were wetted for either 15, 30, or 45 s, and the resulting concentration of dye eluted was determined by spectrophotometry. With the same preparation technique and a 15-s soak time, the strip was applied to wetted filter paper, as a model for the moist surface of the eye. The volume of solution delivered was calculated by weight. Concentrations of rose bengal for the various soak times were: 15 s: 7.64 (+/- 1.11) by 10(-6) g/ml; 30 s: 9.70 (+/- 1.79) by 10(-6) g/ml; and 45 s: 10.27 (+/- 0.66) by 10(-6) g/ml. The volume delivered to the eye model with this technique was 17.43 microliters (+/- 3.09). The concentration of rose bengal dye delivered to the ocular surface by means of a wetted strip is relatively low and soak time/technique-dependent. This suggests a possibility that results in clinical studies with rose bengal strip application may be different than if controlled volume applications of commercially available 1% liquid rose bengal dye are used.

Scanning electron microscopy of polished, slightly etched rock surfaces: A method to observe palynomorphsin situ

Abstract Scanning electron microscopy of polished, slightly etched rock surfaces provides excellent observation conditions for palynomorphs. In the present study, samples from micritic limestone‐marl alternations in the Silurian of Gotland, Sweden, and from Pliocene limestones of the Bahamas are used. The Silurian limestones contain three‐dimensionally preserved acritarchs, chitinozoans, and prasinophytes, allowing the study of the outer and inner wall surfaces. In contrast, siltstones and marls provide slightly to strongly deformed, partly damaged specimens, which become completely flattened and crushed when the sediment is highly compacted. The observation of palynomorphs in polished surfaces can be considered as a complementary method to the standard preparation technique of hydrofluoric and hydrochloric digestion of rock samples, where it is possible that parts of the palynological spectrum may be lost during heavy‐liquid separation, filtering, centrifugation, or bleaching procedures. The detailed obs...

THE 36TH ANNUAL MEETING OF THE JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY-ABSTRACTS-

The methodology used in diagnostic pathology has for a long time been rather conventional. Macroscopical pathology is mostly a matter of skill and experience and for microscopical pathology standard tissue preparation techniques are still very important. Electronmicroscopy allowed further detail in the morphological analysis and morphometry allowed the quantitation of morphological characteristics. That situation has changed dramatically with the introduction of a large variety of histochemical tools which have provided possibilities for detailed biological and chemical analysis at the tissue, cell and subcellular level. Enzyme activities can be visualized; carbohydrate moieties can be analyzed using lectins; proteins can be specifically identified and localized by immunocytochemistry; nucleic acid content can be assessed by specific staining methods and the genome as well as the complex of cytoplasmic mRNA's can be probed by in situ hybridization. DNA quantitation (by flow or static cytometry) has gained enormously in popularity due to the fact that in many tumor types aneuploid cell populations occur and predict aggressive tumor behavior. Enzymehistochemistry is used for a limited number of specific applications (e.g. analysis of muscle diseases). In the last two decades immunocytochemistry has firmly rooted itself in the diagnostic pathology laboratory. Many diagnoses can no longer be made without support from immunocytochemical studies. In (auto)immune diseases specific patterns of immunoglobulin and complement deposition may reveal the pathogenesis of disease processes (as e.g. in glomerulonephritis). Inflammatory cells can be characterized by cell surface (CD) markers. Cancer cells can be classified using marker proteins. Proteins expressed in a cell cycle dependent manner allow analysis of proliferation at the cell and tissue level. Viral and bacterial antigens' can be detected in order to establish the cause of infectious disease. New possibilities have been provided by in situ hybridization techniques for the localization of DNA and RNA. DNA in situ hybridization has allowed the analysis of cytogenetic abnormalities in interphase nuclei. This is no longer limited to numerical aberrations but also includes complex structural abnormalities. Gene expression can be analyzed by probing for specific mRNA's. The latter techniques have carried diagnostic pathology into the molecular field.

Clustering across concentration gradients

Clustering experiments on surfaces are of fundamental interest to verify theoretical concepts for phase-separation processes such as statistical self-similarity and scaling behaviour. Unfortunately, often the differences between theoretical models are too small to be studied with standard sample preparation techniques, as experimental uncertainties result in variations in the results of the same order of magnitude as the effects that we want to study. In this paper we study a modified approach where two different initial morphologies are prepared on the same surface so that the dynamic processes occur in parallel under identical conditions. From observations of clustering near the concentration step we find that the material transfer during late stage ripening is limited to within a distance that is less than the diffusion length. This result is in agreement with a theoretical model that predicts that the interface is confined to a width of the order of the cluster–cluster distance. The two sides beyond this length evolve independently.

An image-directed robotic system for precise orthopaedic surgery

The authors have developed an image-directed robotic system to augment the performance of human surgeons in precise bone machining procedures in orthopaedic surgery, initially targeted at cementless total hip replacement surgery. The total system consists of an interactive CT-based presurgical planning component and a surgical system consisting of a robot, redundant motion monitoring, and man-machine interface components. In vitro experiments conducted with this system have demonstrated an order-of-magnitude improvement in implant fit and placement accuracy, compared to standard manual preparation techniques. The first generation system described in this paper was used in a successful veterinary clinical trial on 26 dogs needing hip replacement surgery. It was the basis for subsequent development of a second-generation system that is now in human clinical trials.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Automated morphometric analysis of stallion spermatozoa

Summary Tissue variation in microscope slides made for spermatozoon analysis and variation introduced by the subjective techniques used to analyze these slides reduce the statistical power of studies that seek to use spermatozoon morphology to predict fertility. A simple specimen preparation method was developed to standardize stallion spermatozoon morphologic smears, and a new, automated spermatozoa morphometry instrument was used to objectively analyze the efficacy of the specimen preparation technique. The method achieved a standard spermatozoon concentration and reduced field-to-field variation in the number of spermatozoa analyzed. Metric measurements of spermatozoon head dimensions from clinically normal, fertile stallions revealed small, but highly significant, differences between stallions. The variation in metric measurements between replicate slides within stallions was small, indicating that replicate slide analysis probably is not necessary for clinically normal stallions. Coefficients of variation were generally &lt; 11% for metric measurements between stallions, and were &lt; 4% within stallions. This study revealed that a high degree of statistical power can be achieved when using these new, standardized specimen preparation and objective analysis techniques. Such power makes possible the detection of subtle differences between clinically normal stallions, and may facilitate accurate detection of abnormal fertility (ie, subfertility) installions.

Cost effective diet instruction using a video developed for infants and children who require a specialized formula

In an economic arena where cost containment and productivity are critical for survival, many dietitians in acute care find that a large portion of their time is directed at providing diet education/instruction which is not reimbursable. Depending on the complexity of the diet the time required for a diet instruction (DI) may range from 30 – 90 minutes. Children with special nutritional requirements who need a special formula prepared after discharge were found to require the greatest amount of time to properly instruct the parents. In addition to concerns regarding staffing cost, the lack of standardization of the content of the DI was identified as a problem. In an attempt to develop time effective patient education methodologies and to standardize instructional materials, a video was developed for parents and health care professionals involved in the management of infants and children who require a special formula. The 15 minute video included basic nutrition principles, standard formula preparation techniques, and parental questions and concerns. Printed materials were developed to support the video. A study was conducted to compare the effectiveness of video instruction (VI) to individual DI; and the staffing time required for each method. Twenty-five adults were included in the study, 15 in the VI group, 10 in the DI group. Both groups were administered a pre and post test. The DI group received individual diet instruction based on a clinical protocol. The VI group viewed the video that was administered by a student and had no interaction with a dietitian. Results included: Tabled 1 Dietitian Instructed (DI) [n = 10] Video Instructed (VI) [n = 15] Correct Response [Mean Percent] Pre Test 65% 60% Post Test 89 91 Time Required 48 minutes 15 minutes Open table in a new tab The DI group pre/post test score increased by 24%, and VI group by 31%. The DI group required approximately 33 minutes more of staff time per instruction than the VI group. In addition, the staff competency required between the two groups differed significantly with the DI group requiring a staff RD with an expertise in pediatrics, whereby the VI group utilized a student/technician. This experience demonstrated that video education can be an effective method for providing diet instruction and a cost effective tool for inpatient services. Dietitians must direct efforts toward redefining the services they provide in the hospital arena to those that are revenue producing and demonstrate cost effective strategies.

Ion chromatographic investigation of brown algae ( Fucus vesiculosus) of the German Environmental Specimen Bank

An investigation of the inorganic anions and cations Cl −, HPO 4 2−, NO 3−, SO 4 2−, NH 4 +, K + and Na + in brown algae collected from various locations in the North Sea and Baltic Sea is presented. Ion chromatography was effectively used for the simultaneous determination of anions and cations after extraction of the homogenized algae samples with deionized water following the standard preparation technique of the German Environmental Specimen Bank (ESB). Acidic and enzymatic digestion was applied to investigate the completeness of cell disintegration in the homogenized algae samples. Results obtained with brown algae clearly indicate the influence of environmental pollution in the North Sea and the Baltic Sea.

An alternative procedure for ESR identification of irradiated chicken drumsticks

The ESR spectroscopy is, at present, the most established technique for quantitative analysis of irradiated chicken bone using the additive dose method. In this paper we tried a different approach to the problem analyzing the ESR behavior of a batch of chicken bone samples coming randomly from the market. Using a suitable and standardized sample preparation technique and sample positioning in the microwave cavity, we obtained a coefficient of variation of about 30% for the batch response. The calibration curve, obtained using the batch behavior up to 10 kGy, was used for a quantitative test on unknown samples.

TEM sample preparation with focused ion beams

The continuing reduction in the sizes of features of interest for integrated circuit failure analysis requires greater precision in transmission electron microscopy (TEM) sample preparation. With minimum feature sizes approaching 0.5 μm, the mere finding of such a feature at a polished edge, let alone preparing a TEM sample containing it becomes a formidable task. The required substantial thinning also increases the risk of loss of what may be a unique sample.We present in this paper a technique that allows localized thinning of cross-sectional TEM samples using a focused ion beam (FIB) machine. Standard preparation techniques are used to make a cross-sectional TEM sample that would otherwise be too thick to be very useful for TEM analysis. This sample is then placed in the FIB machine, which is used as a micromachining tool. No special surface preparation is necessary and the secondary electron signal generated by the ion beam provides an image that can be used to locate the feature of interest.

Etching studies of stress-induced surface polygonization in SI GaAs wafers

Surface etching studies have been performed on Si GaAs wafers grown by liquid encapsulated Czochralski (LEC) and vertical encapsulated zone melting (VZM) techniques. The wafers were sliced, mechanically polished and dipped in a bromine-methanol solution to remove surface damage, which is the standard wafer preparation technique. Surface polygonization has been seen using an eutectic etch in both the LEC and VZM wafers polished in this manner. The polygonized surface “cells” grew in size at higher etching temperatures and/or longer etching times at lower temperatures. If the wafers were dipped for a much longer time in the bromine-methanol solution, it was found that no surface polygonization occurred after the use of the eutectic etch. Thus, we conclude that this polygonization process is driven by relaxation of strain which was introduced in the initial cutting and polishing, and which was not fully relieved by the short bromine-methanol dip.