Standard Preparation Techniques Research Articles

Comparison of Otolith Readability and Reproducibility of Counts of Translucent Zones Using Different Otolith Preparation Methods for Four Endemic Labeobarbus Species in Lake Tana, Ethiopia

The analysis of fish age data is vital for the successful conservation of fish. Attempts to develop optimal management strategies for effective conservation of the endemic Labeobarbus species are strongly affected by the lack of accurate age estimates. Although methodological studies are key to acquiring a good insight into the age of fishes, up to now, there have not been any studies comparing different methods for these species. Thus, this study aimed at determining the best method for the endemic Labeobarbus species. Samples were collected from May 2016 to April 2017. Asteriscus otoliths from 150 specimens each of L. intermedius, L. tsanensis, L. platydorsus, and L. megastoma were examined. Six methods were evaluated; however, only three methods resulted in readable images. The procedure in which whole otoliths were first submerged in water, and subsequently placed in glycerol to take the image (MO1), was generally best. Except for L. megastoma, this method produced the clearest image as both the coefficient of variation and average percentage error between readers were lowest. Furthermore, except for L. megastoma, MO1 had high otolith readability and no systematic bias. Therefore, we suggest that MO1 should be used as the standard otolith preparation technique for the first three species, while for L. megastoma, other preparation techniques should be evaluated. This study provides a reference for researchers from Africa, particularly Ethiopia, to develop a suitable otolith preparation method for the different tropical fish species.

Dentists’ Knowledge, Attitude and Practice of Root Canal Treatment Procedure: Survey-based Research

The aim of this survey was to assess the dentists' knowledge, attitude and practice of endodontic treatment procedures and materials in Damascus city (capital of Syria), and the effect of endodontic specialty and years of experience on the survey findings. Two hundred direct contacts (25 multiple-choice questions containing) questionnaires were distributed to randomly selected dentists practicing in Damascus city in 11 different areas, and a questionnaire contained questions regarding dentists' knowledge, attitude, and practice of root canal treatment procedure. The collected data were entered into a personal computer and analyzed using the statistical package for the social sciences (SPSS), 25 edition. One hundred eighty-eight questionnaires were collected with a 94% response rate. About 71.8% were general dental practitioners (GDPs), 25.5% were not practicing molar endodontics, and only 5.3% were referring difficult cases to endodontists. 32.4% and 21.8% of respondents were practicing vital and necrotic single visit root canal treatment, respectively. Only 6.9% were using rubber dam isolation, and more than half of the respondents used the standardized preparation technique. Non-setting calcium hydroxide was used 100% as an intra-canal medicament during necrotic root canal treatment sessions.96.3% of our respondents prefer delaying final restoration to next visit for symptoms disappearance. It was evident that more practicing experience does not improve treatment options selections of endodontic treatment. So the continuous educational programs are a very important way to change the old or wrong concepts in dental offices. The sample covered a large number of dentists who are working in Damascus; the most developed place in Syria. It is also considered that for carrying out such kind of surveys as long as the dentists are familiar with this type of studies.

Molecular Breast Imaging: Administered Activity Does Not Require Adjustment Based on Patient Size.

At our institution, molecular breast imaging (MBI) is performed with 300 MBq of 99mTc-sestamibi for all patients. For some nuclear medicine procedures, administered activity or imaging time is increased for patients of larger size to obtain adequate counts. Our objective was to assess whether uptake of 99mTc-sestamibi in the breast is influenced by patient size. Methods: Records from patients who underwent a clinical MBI examination between July and November 2016 were reviewed. Those in whom our standard injection and preparation techniques were followed were included in the analysis. Patients were injected with approximately 300 MBq of 99mTc-sestamibi. Residual activity was measured to allow calculation of exact administered activity for each patient. Breast images were acquired at 10 min/view using a dual-head cadmium zinc telluride-based γ-camera. Breast thickness was measured as the distance between the 2 detectors. Patient height, weight, body surface area, and body mass index were obtained from records. Lean body mass with the James equation (LBMJames) and Janmahasatian correction (LBMJanma) was calculated. Count density in the breast tissue was measured by drawing a region of interest around the central breast tissue of the right breast mediolateral-oblique view of the lower detector. Count density was expressed as cts/cm2/MBq of administered activity. Spearman correlation coefficient (rs) was calculated. Results: A total of 200 patients were analyzed. No dose infiltration was suspected at any injection. Average administered activity was 292 MBq (SD, 13.8 MBq; range, 247-326 MBq). Average count density was 7.2 cts/cm2/MBq (SD, 2.7 cts/cm2/MBq; range, 3.1-17.8 cts/cm2/MBq). MBI count density was weakly negatively correlated with height (rs = -0.18; P = 0.01), weight (rs = -0.23; p = <0.001), body mass index (rs = -0.16; P = 0.02), body surface area (rs = -0.22; P = 0.002), LBMJames (rs = -0.23; P = 0.001), and LBMJanma (rs = -0.23; P = 0.001). No correlation was observed between count density and breast thickness (rs = 0.06; P = 0.37). Conclusion: Our results suggest a lack of relationship between uptake of 99mTc-sestamibi in breast tissue and body size or compressed breast thickness. Altering from the standard 300 MBq of administered activity for larger patients is likely unnecessary.

Selectively Electron-Transparent Microstamping Toward Concurrent Digital Image Correlation and High-Angular Resolution Electron Backscatter Diffraction (EBSD) Analysis.

Digital image correlation (DIC) in a scanning electron microscope and high-angular resolution electron backscatter diffraction (HREBSD) provide valuable and complementary data concerning local deformation at the microscale. However, standard surface preparation techniques are mutually exclusive, which makes combining these techniques in situ impossible. This paper introduces a new method of applying surface patterning for DIC, namely a urethane microstamp, that provides a pattern with enough contrast for DIC at low accelerating voltages, but is virtually transparent at the higher voltages necessary for HREBSD and conventional EBSD analysis. Furthermore, microstamping is inexpensive and repeatable, and is more suitable to the analysis of patterns from complex surface geometries and larger surface areas than other patterning techniques.

Femtosecond laser machining for characterization of local mechanical properties of biomaterials: a case study on wood

The standard preparation technique for micro-sized samples is focused ion beam milling, most frequently using Ga+ ions. The main drawbacks are the required processing time and the possibility and risks of ion implantation. In contrast, ultrashort pulsed laser ablation can process any type of material with ideally negligible damage to the surrounding volume and provides 4 to 6 orders of magnitude higher ablation rates than the ion beam technique. In this work, a femtosecond laser was used to prepare wood samples from spruce for mechanical testing at the micrometre level. After optimization of the different laser parameters, tensile and compressive specimens were produced from microtomed radial-tangential and longitudinal-tangential sections. Additionally, laser-processed samples were exposed to an electron beam prior to testing to study possible beam damage. The specimens originating from these different preparation conditions were mechanically tested. Advantages and limitations of the femtosecond laser preparation technique and the deformation and fracture behaviour of the samples are discussed. The results prove that femtosecond laser processing is a fast and precise preparation technique, which enables the fabrication of pristine biological samples with dimensions at the microscale.

A new Cheirolepidiaceae (Coniferales) from the Early Jurassic of Patagonia (Argentina): Reconciling the records of impression and permineralized fossils.

Plants preserved in different fossil modes provide complementary data concerning the paleobiology and evolutionary relationships among plant groups. New material from the Early Jurassic of Patagonia shows the importance of combining these sources of information, as we describe the first compression/impression fossils of Pararaucaria, a genus of the extinct conifer family Cheirolepidiaceae previously known from permineralized fossils. These fossils extend the temporal range of this genus and may allow its wider recognition in the fossil record. We studied fossil plants from the Early Jurassic (Pleinsbachian-Toarcian) locality of Taquetrén in Patagonia, Argentina using standard paleobotanical preparation and description techniques. Pararaucaria taquetrensis consists of isolated ovuliferous scales and small seed cones with helically arranged bract-scale complexes attached to scale-leaf foliage. Bract-scale complexes consist of separated bracts and ovuliferous scales with two seeds and three broad distal lobes. Pararaucaria taquetrensis represents the oldest known Cheirolepidiaceae seed cones from the Southern Hemisphere, and this material highlights the importance of compression and impression fossils in understanding the distribution of fossil taxa. This material also suggests that Cheirolepidiaceae cone scales can be easily confused with those of another common conifer family, the Araucariaceae, which has important implications for accurately understanding Mesozoic conifer diversity and paleoecology.

A Study on Denoising of Poisson Noise in Pap Smear Microscopic Image

Objectives: To study and implement various spatial domain denoising filters on various Pap Smear microscopic images. Methods/Statistical Analysis: In this paper, we calculated the performance metrics to estimate best fit filtering technique among the filters considered for this study. Study of around 300 microscopic Pap Smear images with low and high color densities are considered which includes images from two different standard slide preparation techniques i.e. Conventional Based Cytology (CBC) and Liquid Based Cytology (LBC). Performance of different filters is analyses based on performance metrics like PSNR, MSE, NAE and SNR. Findings: Poisson noise is more likely in Pap Smear images as it is captured using CCD camera at microscopic eye piece. From this study it was found that adaptive wiener filter can be used to reduce Poisson noise in both LBC and CBC Pap Smear Microscopic image. Application/Improvements: This helps to improve analysis result for pathologists using computer aided diagnosis system.

EVALUATION OF SINGLE TRACKS OF 17-4PH STEEL MANUFACTURED AT DIFFERENT POWER DENSITIES AND SCANNING SPEEDS BY SELECTIVE LASER MELTING

In Selective Laser Melting, the initial units produced are single tracks that overlap to create a single layer; from the sequence of layers, a 3D object is manufactured. The properties of the parts produced by SLM depend heavily on the properties of each single track and each layer formed by these tracks. This study evaluates the effect of processing parameters on the geometrical characteristics of single tracks manufactured from 17-4PH stainless steel powder. A single-mode continuous-wave ytterbium fibre laser was used to manufacture single tracks at laser powers in the range of 100-300 W with a constant spot size of ∼ 80μm. The single tracks produced were subjected to standard metallographic preparation techniques for further analysis with an optical microscope. Deep molten pool shapes were observed at low scan speeds, while shallow molten pool shapes were observed at high scan speeds. At higher laser power densities, under-cutting and humping effects were also observed. The dimensions of single tracks processed without powder generally decrease with increasing scan speed at constant laser power. However, the geometrical features of the single tracks processed with powder revealed pronounced irregularities believed to be caused by non-homogeneity in the deposited powder layer.

Assessment of head gunshot wounds by means of post-mortem computed tomography in exhumed anonymous cadaver

Autopsy of corpses with advanced post-mortem changes is the most challenging aspect of medico-legal activities. In many cases, owing to soft tissue decomposition, making a final diagnosis as to the mechanism and cause of death is very difficult, and sometimes impossible (Carcione P, Argo G, Pincone D, Zgo S, Scopelliti L, Sortino C, Procaccianti P. Role of MCT vitropsy in evaluation of burned bodies and its comparison with traditional autopsy. Poster No.: C-1156, ECR 2014, Scientific exhibit). In such cases, the diagnostic process can be supported by post-mortem CT imaging. Post-mortem multislice CT imaging used in the field of forensic medicine is widely reported to be a good method for visualizing injuries and natural pathologies; however, only a limited number of forensic departments use this method in everyday practice. This method enables accurate assessment of bony injuries (fracture type, degree of bone displacement); has the ability to detect radiopaque foreign bodies, most frequently fragments of bullets; and in some cases enables soft tissue delineation (Hardy K. CT autopsy. Radiology Today 2008; 9: 20. Available from: http://www.radiologytoday.net/archive/rt01282008p20.shtml). In cadavers with advanced post-mortem changes, it is extremely difficult to retrieve the whole bullet or its parts. Owing to decomposition and reduced cohesion of the tissues, standard autopsy preparation techniques are impossible to perform. Post-mortem changes may also cause displacement of the bullet within the body in the long term, as well as at the time of transport following exhumation (Maiese A, Gitto L, De Matteis A, Panebianco V, Bolino G. Post mortem computed tomography: useful or unnecessary in gunshot wounds deaths? Two case reports. Leg Med (Tokyo) 2014; 16: 357–63). It is therefore important to perform post-mortem CT imaging directly after extraction of corpses in a similar position to how the dead body was exhumed. Interpretation of the images requires cooperation of forensic medicine specialists and radiologists to correlate radiological findings with autopsy.

Near surface latent track morphology of SHI irradiated TiO2

The material response to SHI irradiation of simple oxides such as TiO2 is markedly different in the near surface volume than in the bulk. In this subsurface region, several tens of nanometers in thickness, the material exhibits a much higher sensitivity to damage creation. The enhanced sensitivity of the material in this region is related to the proximity of a free surface and not strongly dependent on electronic stopping power. At least for these materials, the assumption of cylindrical latent tracks is dubious and great care should be taken when inferring track radii from indirect techniques. Direct observation by TEM can also easily lead to grossly over estimated track radii when most standard specimen preparation techniques are employed. We suggest reduced internal pressure in the crystal in the vicinity of a free surface as the enabling factor for this enhanced sensitivity. Lower pressure leads to increased probability of a phase change due to elevated temperatures in the track core and volume expansion leads to the formation of hillock on the surface of the crystal.

Fast all-optical nuclear spin echo technique based on EIT

We demonstrate an all-optical Raman spin echo technique, using Electromagnetically Induced Transparency (EIT) to create the different pulses of the spin echo sequence: initialization, pi-rotation, and readout. The first pulse of the sequence induces coherence directly from a mixed state, and the technique is used to measure the nuclear spin coherence of an inhomogeneously broadened ensemble of rare-earth ions (Pr$^{3+}$). In contrast to previous experiments it does not require any preparatory hole burning pulse sequences, which greatly shortens the total duration of the sequence. The effect of the different pulses is characterized by quantum state tomography and is compared with simulations. We demonstrate two applications of the technique by using the spin echo sequence to accurately compensate a magnetic field across our sample, and to measure the coherence time at high temperatures up to 11 K, where standard preparation techniques are difficult to implement. We explore the potential of the technique and possible applications.

An Optimized Preparation Technique for Saphenous Vein Graft

An Optimized Preparation Technique for Saphenous Vein Graft

The ReactorAFM: non-contact atomic force microscope operating under high-pressure and high-temperature catalytic conditions.

An Atomic Force Microscope (AFM) has been integrated in a miniature high-pressure flow reactor for in-situ observations of heterogeneous catalytic reactions under conditions similar to those of industrial processes. The AFM can image model catalysts such as those consisting of metal nanoparticles on flat oxide supports in a gas atmosphere up to 6 bar and at a temperature up to 600 K, while the catalytic activity can be measured using mass spectrometry. The high-pressure reactor is placed inside an Ultrahigh Vacuum (UHV) system to supplement it with standard UHV sample preparation and characterization techniques. To demonstrate that this instrument successfully bridges both the pressure gap and the materials gap, images have been recorded of supported palladium nanoparticles catalyzing the oxidation of carbon monoxide under high-pressure, high-temperature conditions.

A silver-stain modification of standard histological slide preparation for use in anthropology analyses.

The traditional histology method typically employed by forensic anthropologists involves plastic embedding of undecalcified bone. The embedded sample is then cut by a diamond blade saw and ground to the required thickness of ~50-100 microns using a grinder. There are several limitations to this method: Cement lines may be blurred; depth-of-field artifacts may result from viewing thick sections; and medicolegal offices with limited budgets may not be able to invest in additional equipment or training for this method. A silver nitrate stain modification of the standard histology preparation technique of decalcified bone is presented. The benefits of this technique are that: Cement lines are viewed clearly; no depth-of-field artifacts are present; and because this is a modification of the standard technique used by histology laboratories typically employed by medicolegal offices, no additional equipment or training is required.

Investigation into alternative sample preparation techniques for the determination of heavy metals in stationary source emission samples collected on quartz filters.

Monitoring stationary source emissions for heavy metals generally requires the use of quartz filters to collect samples because of the high temperature and high moisture sampling environment. The documentary standard method sample preparation technique in Europe, EN 14385, uses digestion in hydrofluoric acid and nitric acid (HF/HNO3) followed by complexing with boric acid (H3BO3) prior to analysis. However, the use of this method presents a number of problems, including significant instrumental drift during analysis caused by the matrix components, often leading to instrument breakdown and downtime for repairs, as well as posing significant health and safety risks. The aim of this work was to develop an alternative sample preparation technique for emissions samples on quartz filters. The alternative techniques considered were: (i) acid digestion in a fluoroboric acid (HBF4) and HNO3 mixture and (ii) acid extraction in an aqua regia (AR) mixture (HCl and HNO3). Assessment of the effectiveness of these options included determination of interferences and signal drift, as well as validating the different methods by measurement of matrix certified reference materials (CRMs), and comparing the results obtained from real test samples and sample blanks to determine limits of detection. The results showed that the HBF4/HNO3 mixture provides the most viable alternative to the documentary standard preparation technique.

나노구조 표면에 관한 문헌고찰

The nano-surface modification techniques could be classified; internal modifications which enhance surface roughness and porosity in nano level and external modifications as nano particle coating. Nano-modified implant surface has various morphograpies such as nanotube, nanopit, nanonodule and polymorphic structures. Creating surface depends upon preparation method and material, however, there is no standard preparation technique not yet. The nano-modified surfacet is electrochemically stable comparing with the surface modified in micron level. Nano-modified surface has little cytotoxicity, stimulates osteoblast proliferation and differentiation. Moreover, it decreases soft tissue intervention by interrupting the proliferation of fibroblast. Nanostructure has similar size and shape with cells and proteins, consequently leads to good biocompatibility and enhanced osseointegration. However, the actual effect in vivo is limited, due to the distance of effect. Even if nano-modified surface has antibiotic property due to photocatalysis, short duration time makes clinical application questionable. Further investigations should focus on the optimal nano-modified surface, which has many potentials.

Reduction in Surface Contamination with Cyclophosphamide in 30 US Hospital Pharmacies following Implementation of a Closed-System Drug Transfer Device

In a follow-up to a previous study, surface contamination with the antineoplastic drug cyclophosphamide was compared in 30 US hospital pharmacies from 2004 to 2010 following preparation with standard drug preparation techniques or the PhaSeal closed system drug transfer device (CSTD). Wipe samples were taken from biological safety cabinet (BSC) surfaces, BSC airfoils (the front leading edge of the BSC), floors in front of BSCs, and countertops in the pharmacy, and they were analyzed for contamination with cyclophosphamide. Contamination was reassessed after a minimum of 6 months following the implementation of the CSTD. Surface contamination (ng/cm(2)) was compared between the 2 techniques and between the previous and current test periods and evaluated with the Kruskal-Wallis test. With the use of CSTD compared to the standard preparation techniques, a significant reduction in levels of contamination with cyclophosphamide was observed (P < .0001). Median values for surface contamination with cyclophosphamide were reduced by 86% compared to 95% in the previous study. The CSTD significantly reduced, but did not totally eliminate, surface contamination with cyclophosphamide. In addition to other protective measures, increased usage of CSTDs should be employed to help protect health care workers from exposure to hazardous drugs.

Route towards cylindrical cloaking at visible frequencies using an optimization algorithm

We derive a model based on the Maxwell-Garnett effective-medium theory that describes a cylindrical cloaking shell composed of metal rods which are radially aligned in a dielectric host medium. We propose and demonstrate a minimization algorithm that calculates for given material parameters the optimal geometrical parameters of the cloaking shell such that its effective optical parameters fit the best to the required permittivity distribution for cylindrical cloaking. By means of sophisticated full-wave simulations we find that a cylindrical cloak with good performance using silver as the metal can be designed with our algorithm for wavelengths in the red part of the visible spectrum ($623\phantom{\rule{0.28em}{0ex}}$nm $&lt;\ensuremath{\lambda}&lt;773\phantom{\rule{0.28em}{0ex}}$nm). We also present a full-wave simulation of such a cloak at an exemplary wavelength of $\ensuremath{\lambda}=729\phantom{\rule{0.28em}{0ex}}$nm ($\ensuremath{\hbar}\ensuremath{\omega}=1.7\phantom{\rule{0.28em}{0ex}}$eV) which indicates that our model is useful to find design rules of cloaks with good cloaking performance. Our calculations investigate a structure that is easy to fabricate using standard preparation techniques and therefore pave the way to a realization of guiding light around an object at visible frequencies, thus rendering it invisible.

A Randomized, Double‐blinded Placebo‐controlled Clinical Trial of the Routine Use of Preoperative Antibiotic Prophylaxis in Modified Radical Mastectomy

The effectiveness of antibiotic prophylaxis for prevention of surgical site infection (SSI) following specific types of breast cancer surgery remains uncertain. This study assessed the effectiveness of prophylaxis in modified radical mastectomy (MRM). Women undergoing MRM for breast cancer were recruited. Women were excluded who had diabetes mellitus, severe malnutrition or known allergy to cephalosporins; were receiving corticosteroid therapy or were treated with antibiotics within one week prior to surgery; were scheduled for simultaneous breast reconstruction or bilateral oophorectomy; had existing local infection. Participants were randomized to receive either intravenous cefazolin 1 g or placebo within 30 min prior to skin incision. Standard skin preparation and operative technique for MRM were carried out. Wounds were assessed for SSI and other complications weekly for 30 days. A total of 254 women were recruited. Age, clinical stage, prior chemotherapy, and operative time were similar for antibiotic and placebo groups. The overall incidence of SSI was 14.2 %. There were no significant differences in the infection rate over the 30-day follow-up period between the placebo and antibiotic groups (15 % vs 13.4 %; p = 0.719) or at each week. The majority of SSI were either cellulitis or superficial infection for both groups. There were no significant differences between groups in treatments required for SSI, incidence of hematoma or seroma. The findings of this study, alone and when meta-analyzed with data from studies in similar surgical populations, do not support the use of antibiotic prophylaxis in MRM.

Standard karyotyping concentrates microfilaria and can be a valid concentrating technique for their detection

During karyotype preparation from the bone marrow aspirates of 209 haematological malignancy cases, microfilaria were detected in four samples, whereas routine marrow and peripheral blood smears of these four cases did not show any parasite. The patients were recalled, and their peripheral blood was processed by karyotyping and standard concentration techniques. Karyotype preparation from peripheral blood was performed with and without addition of colchicine. When the blood was processed for karyotyping with colchicine, microfilaria were detected in the peripheral blood of all four patients. In samples without added colchicine, no parasite was observed. The same samples were processed by Knott's concentration technique, which showed microfilariae only in one of the four patients. Routine thick and thin smears of these patients showed no parasite. It seems that the standard karyotype preparation technique with colchicine concentrates the microfilariae in samples where parasite load is small and not demonstrable with standard techniques. Serological tests are available for W.bancrofti and costly, whereas no regular serodiagnosis is available for B.malayi. In a country like India, both parasites are endemic and patients are treated on clinical suspicion when parasitaemia could be low. Low parasitaemia is common because of repeated infection and partial immunity. In such circumstances, a cost-effective concentration technique like this may be useful.