Multivariate Analysis of Solubility Parameters for Drug-Polymer Miscibility Assessment in Preparing Raloxifene Hydrochloride Amorphous Solid Dispersions.

The success of obtaining solid dispersions for solubility improvement invariably depends on the miscibility of the drug and polymeric carriers. This study aimed to categorize and select polymeric carriers via the classical group contribution method using the multivariate analysis of the calculated solubility parameter of RX-HCl. The total, partial, and derivate parameters for RX-HCl were calculated. The data were compared with the results of excipients (N = 36), and a hierarchical clustering analysis was further performed. Solid dispersions of selected polymers in different drug loads were produced using solvent casting and characterized via X-ray diffraction, infrared spectroscopy and scanning electron microscopy. RX-HCl presented a Hansen solubility parameter (HSP) of 23.52 MPa1/2. The exploratory analysis of HSP and relative energy difference (RED) elicited a classification for miscible (n = 11), partially miscible (n = 15), and immiscible (n = 10) combinations. The experimental validation followed by a principal component regression exhibited a significant correlation between the crystallinity reduction and calculated parameters, whereas the spectroscopic evaluation highlighted the hydrogen-bonding contribution towards amorphization. The systematic approach presented a high discrimination ability, contributing to optimal excipient selection for the obtention of solid solutions of RX-HCl.

Formulation and Optimization of Diclofenac Sodium Loaded Ethylcellulose Nanoparticles

Abstract Design of experiment (DoE) is a useful time and cost-effective tool for analyzing the effect of independent variables on the formulation characteristics. The aim of this study is to evaluate the effect of the process variables on the characteristics involved in the preparation of Diclofenac Sodium (DC) loaded ethylcellulose (EC) nanoparticles (NP) using Central Composite Design (CCD). NP were prepared by W/O/W emulsion solvent evaporation method. Three factors were investigated (DC/EC mass ratio, PVA concentration, homogenization speed) in order to optimize the entrapment efficiency (EE) and the particle size of NP. The optimal formulation was characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), and in vitro release. Optimized formulation showed an EE of 49.09 % and an average particle size of 226.83 nm with a polydispersity index of 0.271. No drug-polymer interaction was observed in FTIR and DSC analysis. SEM images showed that the particles are spherical and uniform. The in vitro release study showed a sustained release nature, 53.98 % of the encapsulated drug has been released over 24hours period. This study demonstrated that statistical experimental design methodology can optimize the formulation and the process variables to achieve favorable responses.

Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy.

OBJECTIVE: This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. METHODS: 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F-, 4 min.); Laser+APF (Nd:YAG laser irradiation-0.6W, 84.9J/cm2, 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT (quantification of optical attenuation coefficient-OAC) and FTIR (analysis of carbonate and phosphate content) before treatments, after treatments, and on the 5th, 10th and 15th days of pH-cycling. The statistical analysis was performed (α = 5%). RESULTS: The Optical Attenuation Coefficient (OAC) assessed by OCT increases with the progression of demineralization, and the Laser+APF presented the highest values of OAC in 10th and 15th days of pH-cycling. Nd:YAG decreased the carbonate content after treatment regardless of the application order of the APF-gel, while APF-gel did not interfere in the composition of enamel. The carbonate content was also changed in the first 5 days of the pH-cycling in all groups. CONCLUSION: Nd:YAG laser irradiation before or after the application of APF-gel did not influence the appearance of incipient caries lesions, showing no synergistic effect. Regardless of the application order of the APF-gel, laser irradiation reduces the carbonate content of the enamel, which also changes during the demineralization process. However, irradiation before the application of APF-gel increased the speed of progression of the lesions, which positively impacts public health as it can prevent caries disease, even in high risk individuals. OCT and FTIR are suitable for assessing this effect.

Assessment of erythrocyte morphology in patients with type 2 diabetes mellitus: a pilot study of electron microscopy-based analysis in relation to healthy controls

Background/aim: The present study aimed to assess erythrocyte morphology in newly diagnosed type 2 diabetes mellitus patients using scanning electron microscopy. Materials and methods: In total, 30 patients admitted to endocrine outpatient clinics were included in the study. The patients were divided into two groups according to their fasting blood glucose levels: type 2 diabetes mellitus (n = 15, fasting blood glucose levels ≥ 126 mg/dL) and control (n = 15, fasting blood glucose levels < 99 mg/dL). The patient's demographic characteristics, haemoglobin A1c levels, and scanning electron microscopy findings regarding erythrocyte morphology were recorded. Results: There was no significant difference between the control and type 2 diabetes mellitus group in terms of the participants' age (51.13 ± 8.53 vs. 50.33 ± 8.72 years, p = 0.8) and the male/female ratio (9/6 vs. 9/6). In the control group, discocytes were abundant, echinocytes were rare, and spherocytes were absent. On the other hand, discocytes were less common and echinocyte-shaped erythrocytes were more common in the type 2 diabetes mellitus group than in the control group. In addition, spherocytes were detected in the type 2 diabetes mellitus group. Moreover, the diameter of discocytes was significantly lower (p = 0.014), and blood glucose and haemoglobin A1c levels were significantly higher (p < 0.05 for both) in the type 2 diabetes mellitus group than in the control group. Conclusion: Our findings indicate that high glucose levels in type 2 diabetes mellitus patients lead to significant alterations in erythrocyte morphology, including decreased erythrocyte deformability and the formation of echinocytes and spherocytes due to eryptosis. The possibility of decreased erythrocyte deformability due to excessive eryptosis may disturb microcirculation in newly diagnosed, treatment-naïve type 2 diabetes mellitus patients who do not have any complications.

Scanning Electron Microscopic Assessment of Stent Coating Integrity in Jailed Wire Technique for Bifurcation Treatment.

OBJECTIVES: To assess the impact of different guidewires on stent coating integrity in jailed wire technique (JWT) for bifurcation treatment. BACKGROUND: JWT is commonly adopted to protect side branch in provisional one-stent strategy for coronary bifurcation lesions. However, this technique may cause defects in stent coatings. The degree of coating damage caused by different types of jailed wires remains unknown. METHODS: A fluid model with a bifurcation was established to mimic the condition in vivo. One-stent strategy was performed with three types of guidewire (nonpolymer-jacketed wire, intermediate polymer-jacketed wire, and full polymer-jacketed wire) tested for JWT. Scanning electron microscopy (SEM) was used to evaluate stent coating integrity and wire structure. The degrees of coating defects were recorded as no, slight, moderate, and severe defects. RESULTS: A total of 27 samples were tested. Analyses of SEM images showed a significant difference in the degree of coating damage among the three types of wire after the procedure of JWT (P < 0.001). Nonpolymer-jacketed wire could inevitably cause a severe defect in stent coatings, while full polymer-jacketed wire caused the least coating damages. Besides, there were varying degrees of coil deformation in nonpolymer-jacketed wires, while no surface damage or jacket shearing was observed in full polymer-jacketed wires. CONCLUSIONS: Although nonpolymer-jacketed wire has long been recommended for JWT, our bench-side study suggests that full polymer-jacketed wire may be a better choice. Further clinical studies are needed to confirm our findings.

Backscattered Scanning Electron Microscopy Approach for Assessment of Microvessels under Conditions of Normal Microanatomy and Pathological Neovascularization.

We evaluated the efficiency of an original method for studying of the microvascular bed under conditions of normal microanatomy and pathological neovascularization. The blood vessels, tissues surrounding the stent in the pulmonary artery and subcutaneously implanted titanium nickelide plate, atherosclerotic plaque, and vascular stent with restenosis were examined. The specimens were fixed in formalin and stained in OsO4, embedded into fresh epoxy resin, grinded, polished, and counterstained with uranyl acetate and lead citrate. Numerous vasa vasorum were found in all native vessels. Around the pulmonary artery stent and metal plates, numerous newly formed vessels of small diameter were seen. The intensity of neovascularization in atherosclerosis and carotid stent restenosis differed significantly. Our technique can be successfully used for evaluation of the microvascular bed.

Multiple fingerprint and fingerprint-activity relationship for quality assessment of polysaccharides from Flammulina velutipes.

Polysaccharides are known as one of the most important bioactive compounds in Flammulina velutipes. However, there is no accurate and comprehensive assessment method to evaluate and authenticate F. velutipes polysaccharides (FVPs) from different sources. In this study, a multiple fingerprint analysis method including scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and high-performance liquid chromatography (HPLC) was established. The inhibitory activities of FVPs against HepG2 were measured and introduced into multiple linear regression (MLR) analysis to investigate fingerprint-activity relationship. The principal component analysis (PCA) scores showed that the polysaccharides extracted from 20 batches of different F. velutipes were highly similar, and substandard samples could be distinguished from the authentic polysaccharides clearly. The glucuronic acid could be considered as a marker for discrimination of white and yellow F. velutipes polysaccharides in HPLC fingerprints. Moreover, the HPLC fingerprint-growth inhibitory activity relationship illuminated that monosaccharides composition played an important role on the HepG2 growth inhibitory activity, and activity-associated markers (mannose, rhamnose, xylose, and galactose) were chosen to assess FVPs from different sources. The suggested HPLC fingerprint-activity relationship method provides an integrated strategy for the quality control of F. velutipes and its related products.

Correlative polarizing light and scanning electron microscopy for the assessment of talc in pelvic region lymph nodes.

Perineal talc use is associated with ovarian carcinoma in many case-control studies. Such talc may migrate to pelvic organs and regional lymph nodes, with both clinical and legal significance. Our goal was to differentiate talc in pelvic lymph nodes due to exposure, versus contamination with talc in the laboratory. We studied 22 lymph nodes from ovarian tumor patients, some of which had documented talc exposure, to quantify talc using digestion of tissue taken from paraffin blocks and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). Talc particles correlated significantly with surface contamination assessments using polarized light microscopy. After adjusting for surface contamination, talc burdens in nodes correlated strongly with perineal talc use. In a separate group of lymph nodes, birefringent particles within the same plane of focus as the tissues in histological sections were highly correlated with talc particles within the tissue by in situ SEM/EDX (r = 0.80; p < 0.0001). We conclude that since talc can be a surface contaminant from tissue collection/preparation, digestion measurements may be influenced by contamination. Instead, because they preserve anatomic landmarks and permit identification of particles in cells and tissues, polarized light microscopy and in situ SEM/EDX are recommended to assess talc in lymph nodes.

Choosing the number of images and image position when analyzing the UNC Passive Aerosol Sampler for occupational exposure assessment.

The University of North Carolina passive aerosol sampler (UNC sampler) could be an alternative when measuring occupational dust exposure, but the time required for microscopic imaging of the sampler needs to be reduced to make it more attractive. The aims of this study were to (1) characterize the effect on precision when reducing imaging, in order to shorten analysis time and (2) assess if the position of the images makes a difference. Eighty-eight samplers were deployed in different locations of an open pit mine. Sixty images were captured for each UNC sampler, covering 51% of its collection surface, using scanning electron microscopy. Bootstrapped samples were generated with different image combinations, to assess the within-sampler coefficient of variation (CVws) for different numbers of images. In addition, the particle concentration relative to the distance from the center of the sampler was studied. Reducing the number of images collected from the UNC sampler led to up to 8.3% CVws for 10 images when calculating respirable fraction. As the overall CV has previously been assessed to 36%, the additional contribution becomes minimal, increasing the overall CV to 37%. The mean concentrations of the images were modestly related to distance from the center of the sampler. The CVws changed from 8.26% to 8.13% for 10 images when applying rules for the image collection based on distance. Thus, the benefit of these rules on the precision is small and the images can therefore be chosen at random. In conclusion, reducing the number of images analyzed from 60 to 10, corresponding to a reduction of the imaged sampling area from 51% to 8.5%, results in a negligible loss in precision for respirable fraction dust measurements in occupational environments.

Biological serial block face scanning electron microscopy at improved z-resolution based on Monte Carlo model.

Serial block-face electron microscopy (SBEM) provides nanoscale 3D ultrastructure of embedded and stained cells and tissues in volumes of up to 107 µm3. In SBEM, electrons with 1-3 keV energies are incident on a specimen block, from which backscattered electron (BSE) images are collected with x, y resolution of 5-10 nm in the block-face plane, and successive layers are removed by an in situ ultramicrotome. Spatial resolution along the z-direction, however, is limited to around 25 nm by the minimum cutting thickness. To improve the z-resolution, we have extracted depth information from BSE images acquired at dual primary beam energies, using Monte Carlo simulations of electron scattering. The relationship between depth of stain and ratio of dual-energy BSE intensities enables us to determine 3D structure with a ×2 improvement in z-resolution. We demonstrate the technique by sub-slice imaging of hepatocyte membranes in liver tissue.

A novel electron-microscopic method for measurement of mineral content in enamel lesions.

OBJECTIVE: To assess Scanning Electron Microscopy in Back-Scattered Emission mode (BSE-SEM) for measurement of lesion mineral content as a function of depth. Direct comparison is made with Transverse Micro-Radiography (TMR) and Surface Micro-Hardness (SMH) on carious and erosive lesions. DESIGN: Caries lesions prepared from sound bovine enamel at 37 °C and pH 4.6 in unsaturated (7d) or part-saturated (8d, 4.1 mM Ca2+, 8 mM Pi) lactic acid /methyl cellulose gel system, followed by TMR analysis. Erosive lesions prepared from sound bovine enamel (1% citric acid, pH3.8, room temperature) for 5, 10, 15 or 20 min at n = 10 per treatment group. SMH readings (Vickers diamond, 1.9 N, 20 s) were taken from acid-treated and reference areas of each sample. BSE-SEM performed on polished cross-sections of lesioned samples (Jeol JSM6490LV SEM; high vacuum, 10 keV beam voltage, magnification x500 with constant working distance of 10 mm). Under identical SEM conditions, polished standards i.e. MgF2, alumina, Mg, Al and Si provided a calibration plot of BSE-SEM signal vs. atomic number (z¯). Mineral content vs. depth plots were derived from the cross-sectional BSE-SEM data. RESULTS: Cross-sectional BSE-SEM images clearly differentiate between caries and erosive lesions. Comparison of caries lesion mineral loss from BSE-SEM with TMR data showed good correlation (R2 = 0.98). Similarly, comparison of BSE-SEM data from erosive lesions showed good correlation (R2 = 0.99) with hardness loss data from SMH. CONCLUSION: BSE-SEM provides a relatively rapid and cost-effective method for the assessment of mineral content in demineralised tooth enamel and is applicable to both caries and erosive lesions.

Methodology for sample preparation and size measurement of commercial ZnO nanoparticles.

This study discusses the strategies on sample preparation to acquire images with sufficient quality for size characterization by scanning electron microscope (SEM) using two commercial ZnO nanoparticles of different surface properties as a demonstration. The central idea is that micrometer sized aggregates of ZnO in powdered forms need to firstly be broken down to nanosized particles through an appropriate process to generate nanoparticle dispersion before being deposited on a flat surface for SEM observation. Analytical tools such as contact angle, dynamic light scattering and zeta potential have been utilized to optimize the procedure for sample preparation and to check the quality of the results. Meanwhile, measurements of zeta potential values on flat surfaces also provide critical information and save lots of time and efforts in selection of suitable substrate for particles of different properties to be attracted and kept on the surface without further aggregation. This simple, low-cost methodology can be generally applied on size characterization of commercial ZnO nanoparticles with limited information from vendors.

Evaluation of Proctophyllodes huitzilopochtlii on feathers from Anna's (Calypte anna) and Black-chinned (Archilochus alexandri) Hummingbirds: Prevalence assessment and imaging analysis using light and tabletop scanning electron microscopy.

Proctophyllodes huitzilopochtlii Atyeo & Braasch 1966 (Acariformes: Astigmata: Proctophyllodidae), a feather mite, was found on feathers collected from five hummingbird species in California. This mite has not been previously documented on feathers from Anna's (Calypte anna [Lesson 1829]) or Black-chinned (Archilochus alexandri [Bourcier & Mulsant 1846]) Hummingbirds. A total of 753 hummingbirds were evaluated for the presence of mites by species (Allen's n = 112; Anna's n = 500; Black-chinned n = 122; Rufous n = 18; Calliope n = 1), sex (males n = 421; females n = 329; 3 unidentified), and age (juvenile n = 199; after-hatch-year n = 549; 5 unidentified). Of these 753 hummingbirds evaluated, mites were present on the rectrices of 40.9% of the birds. Significantly more Anna's Hummingbirds were positive for rectricial mites (59.2%) compared with 8.2% of Black-chinned, 0.9% of Allen's, 5.6% of Rufous Hummingbirds, and 0% for Calliope (p-value < 0.0001). Across all hummingbird species, male hummingbirds (44.9%) had a higher prevalence of rectricial mites compared to female hummingbirds (36.2%; p-value = 0.004), while juvenile hummingbirds (46.2%) had a non-significantly higher prevalence compared to after-hatch-year hummingbirds (39.0%; p-value = 0.089). On average, the percentage of the long axis of the rachis occupied by mites for the outer rectrices (R4 and R5) was 19%, compared to 11% for inner rectrices (R1 and R2), a significant difference (p-value = <0.0001). There was a marginal lack of significance for symmetrical distribution of tail mites with the mean left side percentage of long axis of the rachis occupied by mites being 16% and very close to the mean right side score of 18% (p-value = 0.003). The identification of the feather mite species was based on light microscopic morphometry, and mite distribution on feathers was further evaluated using tabletop scanning electron microscopy (TSEM). The hummingbird-feather mite relationship is not well understood, but the specialized TSEM technique may be especially useful in examining natural positioning and developmental aspects of the mites since it allows in situ feather examination of live mites.

Xyloglucan in the primary cell wall: assessment by FESEM, selective enzyme digestions and nanogold affinity tags.

Xyloglucan has been hypothesized to bind extensively to cellulose microfibril surfaces and to tether microfibrils into a load-bearing network, thereby playing a central role in wall mechanics and growth, but this view is challenged by newer results. Here we combined high-resolution imaging by field emission scanning electron microscopy (FESEM) with nanogold affinity tags and selective endoglucanase treatments to assess the spatial location and conformation of xyloglucan in onion cell walls. FESEM imaging of xyloglucanase-digested cell walls revealed an altered microfibril organization but did not yield clear evidence of xyloglucan conformations. Backscattered electron detection provided excellent detection of nanogold affinity tags in the context of wall fibrillar organization. Labelling with xyloglucan-specific CBM76 conjugated with nanogold showed that xyloglucans were associated with fibril surfaces in both extended and coiled conformations, but tethered configurations were not observed. Labelling with nanogold-conjugated CBM3, which binds the hydrophobic surface of crystalline cellulose, was infrequent until the wall was predigested with xyloglucanase, whereupon microfibril labelling was extensive. When tamarind xyloglucan was allowed to bind to xyloglucan-depleted onion walls, CBM76 labelling gave positive evidence for xyloglucans in both extended and coiled conformations, yet xyloglucan chains were not directly visible by FESEM. These results indicate that an appreciable, but still small, surface of cellulose microfibrils in the onion wall is tightly bound with extended xyloglucan chains and that some of the xyloglucan has a coiled conformation.

A New Approach Combining Analytical Methods for Workplace Exposure Assessment of Inhalable Multi-Walled Carbon Nanotubes.

To date there is no consensus about the most appropriate analytical method for measuring carbon nanotubes (CNTs), hampering the assessment and limiting the comparison of data. The goal of this study is to develop an approach for the assessment of the level and nature of inhalable multi-wall CNTs (MWCNTs) in an actual workplace setting by optimizing and evaluating existing analytical methods. In a company commercially producing MWCNTs, personal breathing zone samples were collected for the inhalable size fraction with IOM samplers; which were analyzed with carbon analysis, inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX). Analytical methods were optimized for carbon analysis and SEM/EDX. More specifically, methods were applied and evaluated for background correction using carbon analyses and SEM/EDX, CNT structure count with SEM/EDX and subsequent mass conversion based on both carbon analyses and SEM/EDX. A moderate-to-high concordance correlation coefficient (RC) between carbon analyses and SEM/EDX was observed [RC = 0.81, 95% confidence interval (CI): 0.59-0.92] with an absolute mean difference of 59 µg m-3. A low RC between carbon analyses and ICP-MS (RC = 0.41, 95% CI: 0.07-0.67) with an absolute mean difference of 570 µg m-3 was observed. The large absolute difference between EC and metals is due to the presence of non-embedded inhalable catalyst particles, as a result of which MWCNT concentrations were overestimated. Combining carbon analysis and SEM/EDX is the most suitable for quantitative exposure assessment of MWCNTs in an actual workplace situation.

A new method using Scanning Electron Microscopy (SEM) for preparation of anisopterous odonates.

Anisopterous odonate male's secondary genitalia is a complex of several structures, among them the vesica spermalis is the most informative with important specific characters. The observation of those characters, mostly of membranous nature, is difficult in the Scanning Electron Microscope due to dehydration and metallization processes. In this contribution, we discuss a new and low cost procedure for the observation of these characters in the SEM, compatible with the most common agents used for preserving specimens.

In-vitro assessment of the effect of dabigatran on thrombosis of adult and neonatal plasma: comparisons using thromboelastography and microscopic visualization of fibrin clot structure.

: Thromboelastography (TEG) is a global assay used for evaluating features of clot formation in vitro. Dabigatran is a reversible direct inhibitor of thrombin that has not been studied in neonates using a sophisticated global assay, such as TEG. Neonatal hemostasis differs from adult hemostasis in both quantitative and qualitative characteristics. Our aim was to compare the TEG clotting profile of neonatal and adult platelet-poor plasma when exposed to different concentrations of dabigatran. We used commercially collected adult pooled plasma and neonatal cord blood collected from placentas of healthy full term newborns. Platelet-poor plasma was isolated, pooled, and frozen. Prior to experiment, plasma was thawed and filtered. A reaction mixture of CaCl2, corn trypsin inhibitor, tissue factor, and dabigatran in imidazole buffer was mixed with plasma in a TEG cup. Time to clot initiation (R-time), speed of clot strengthening (α-angle), and maximum clot strength (maximal amplitude) were measured. Scanning electron microscopy was performed to evaluate fibrin clot structure. Without dabigatran, there was no significant difference in TEG measurements between neonatal and adult samples. However, neonatal plasma clotting with dabigatran had slower onset, slower speed, and weaker clots that were more porous with thicker fibers, compared with adult plasma clotting. Thus, neonatal plasma may be more sensitive to dabigatran as assessed by our in-vitro TEG study.

Exposure Assessment in a Single-Walled Carbon Nanotube Primary Manufacturer.

Objectives: This study was aimed at documenting and characterizing occupational exposure to single-walled carbon nanotubes (SWCNTs) generated in a primary manufacturing plant. It also compared various strategies of exposure monitoring. Methods: A 6-day measurement protocol was scheduled (D1-D6) including both (i) quasi-personal monitoring with an array of direct reading instruments (DRIs) and (ii) offline electron microscopy analyses of surface and breathing zone filter-based samples. The first step (D1 and D2) consisted of contamination screenings resulting from the various SWCNT production tasks using a multimetric approach. Surface sampling was also carried out to assess workplace cross-contamination. The second step (D3-D6) focused on the exposure monitoring during recovery/cleaning task, by comparing three personal elemental carbon (EC) measurements [respirable EC using a cyclone following the NIOSH 5040 method (REC-CYC), respirable and thoracic EC using parallel particle impactors [REC-PPI and TEC-PPI, respectively)] and gravimetric mass concentration measurements. Results: DustTrak DRX and electrical low-pressure impactor measurements indicated that particles were released during weighing, transferring, and recovery/cleaning tasks of the manufacturing process. Electron microscopy revealed the presence of agglomerated SWCNTs only during the recovery/cleaning task. REC-CYC concentrations remained under the limits of quantification; REC-PPI showed levels up to 58 µg m-3; and TEC-PPI ranged from 40 to 70 µg m-3. Ratios calculated between gravimetric measurements and estimated DustTrak mass concentrations ranged from 2.8 to 4.9. Cross-contamination appeared to be limited since SWCNTs was only found on surface samples collected close to the reactor in the production room. Conclusions: This case study showed that the DustTrak DRX should be the preferred device among DRIs to identify potential exposure to SWCNTs. However, there is a risk of false positive since it is a non-specific instrument; therefore, the actual release of SWCNTs must be confirmed with scanning electron microscopy/transmission electron microscopy analyses. Besides, using EC measurements as a proxy for SWCNT exposure assessments, as suggested by the NIOSH, is still challenging since interferences can occur with other EC sources such as carbon black, which is also present in the workplace.

The Diagnostic Value of Quantitative Assessment of Diatom Test for Drowning: An Analysis of 128 Water-related Death Cases using Microwave Digestion-Vacuum Filtration-Automated Scanning Electron Microscopy.

The value of diatom test for the diagnosis of drowning remains controversial. The conventional forensic diatom test with low sensitivity is not a useful tool to provide accurate information about diatom in the tissues and organs. To improve the sensitivity of the diatom test, we developed a novel method called the Microwave Digestion-Vacuum Filtration-Automated Scanning Electron Microscopy (MD-VF-Auto SEM) method which resulted in a high recovery of diatoms. In this article, we analyzed 128 water-related death cases. Our results showed that the MD-VF-Auto SEM method could achieve a much higher positive rate (0.97) in drowning cases. Large amounts of diatoms are retained, even concentrated, in the lung tissues during the intense breathing movement in drowning process. This might be useful for the diagnosis of drowning. Our research indicates that the MD-VF-Auto SEM method would be a valuable methodology in the study of diatom test for the forensic community.

Simultaneous arsenic and fluoride removal from synthetic and real groundwater by electrocoagulation process: Parametric and cost evaluation.

Co-existence of arsenic and fluoride in groundwater has raised severe health issues to living being. Thus, the present research has been conducted for simultaneous removal of arsenic and fluoride from synthetic groundwater by using electrocoagulation process with aluminum electrode. Effects of initial pH, current density, run time, inter electrode distance and NaCl concentration over percentage removal of arsenic and fluoride as well as operating cost have been studied. The optimum experimental conditions are found to be initial pH: 7, current density: 10 A/m2, run time: 95 min, inter electrode distance: 1 cm, NaCl concentration: 0.71 g/l for removal of 98.51% arsenic (initial concentration: 550 µg/l) and 88.33% fluoride (initial concentration: 12 mg/l). The concentration of arsenic and fluoride in treated water are found to be 8.19 µg/l and 1.4 mg/l, respectively, with an operating cost of 0.357 USD/m3 treated water. Pseudo first and second order kinetic model of individual and simultaneous arsenic and fluoride removal in electrocoagulation have also been studied. Produced sludge characterization studies also confirm the presence of arsenic in As(III) form, and fluoride in sludge. The present electrocoagulation process is able to reduce the arsenic and fluoride concentration of synthetic as well as real groundwater to below 10 µg/l and 1.5 mg/l, respectively, which are maximum contaminant level of these elements in drinking water according to WHO guidelines.