Design and fabrication of a differential scanning nanocalorimeter

DOE PAGES

Zuo, Lei; Chen, Xiaoming; Yu, Shifeng; ...

2016-12-19

This paper describes the design, fabrication, and characterization of a differential scanning nanocalorimeter that significantly reduces the sample volume to microliters and can potentially improve the temperature sensitivity to 10 µK. The nanocalorimeter consists of a polymeric freestanding membrane, four high-sensitive low-noise thermistors based on silicon carbide (SiC), and a platinum heater and temperature sensor. With the integrated heater and sensors, temperature scanning and power compensation can be achieved for calorimetric measurement. Temperature sensing SiC film was prepared by using sintered SiC target and DC magnetron sputtering under different gas pressures and sputtering power. The SiC sensing material is characterizedmore » through the measurement of current–voltage curves and noise levels. The thermal performance of a fabricated nanocalorimeter is studied in simulation and experiment. The experiment results show the device has excellent thermal isolation to hold thermal energy. As a result, the noise test together with the simulation show the device is promising for micro 10 µK temperature sensitivity and nanowatt resolution which will lead to low-volume ultra-sensitive nanocalorimetry for biological processes, such as protein folding and ligand binding.« less

Micro-differential scanning calorimeter for liquid biological samples

DOE PAGES

Wang, Shuyu; Yu, Shifeng; Siedler, Michael S.; ...

2016-10-20

Here, we developed an ultrasensitive micro-DSC (differential scanning calorimeter) for liquid protein sample characterization. Our design integrated vanadium oxide thermistors and flexible polymer substrates with microfluidics chambers to achieve a high sensitivity (6 V/W), low thermal conductivity (0.7 mW/K), high power resolutions (40 nW), and well-defined liquid volume (1 μl) calorimeter sensor in a compact and cost-effective way. Furthermore, we demonstrated the performance of the sensor with lysozyme unfolding. The measured transition temperature and enthalpy change were in accordance with the previous literature data. This micro-DSC could potentially raise the prospect of high-throughput biochemical measurement by parallel operation with miniaturizedmore » sample consumption.« less

Determination of Heats of Fusion: Using Differential Scanning Calorimetry for the AP Chemistry Courses.

ERIC Educational Resources Information Center

Temme, Susan M.

1995-01-01

Describes an exercise designed to be used in an Advanced Placement (AP) chemistry course to accompany the study of thermodynamics. Uses Differential Scanning Calorimetry in teaching the concepts of thermochemistry and thermodynamics. (JRH)

DSC, X-ray and FTIR studies of a gemfibrozil/dimethyl-β-cyclodextrin inclusion complex produced by co-grinding.

PubMed

Aigner, Z; Berkesi, O; Farkas, G; Szabó-Révész, P

2012-01-05

The steps of formation of an inclusion complex produced by the co-grinding of gemfibrozil and dimethyl-β-cyclodextrin were investigated by differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD) and Fourier transform infrared (FTIR) spectroscopy with curve-fitting analysis. The endothermic peak at 59.25°C reflecting the melting of gemfibrozil progressively disappeared from the DSC curves of the products on increase of the duration of co-grinding. The crystallinity of the samples too gradually decreased, and after 35min of co-grinding the product was totally amorphous. Up to this co-grinding time, XRPD and FTIR investigations indicated a linear correlation between the cyclodextrin complexation and the co-grinding time. After co-grinding for 30min, the ratio of complex formation did not increase. These studies demonstrated that co-grinding is a suitable method for the complexation of gemfibrozil with dimethyl-β-cyclodextrin. XRPD analysis revealed the amorphous state of the gemfibrozil-dimethyl-β-cyclodextrin product. FTIR spectroscopy with curve-fitting analysis may be useful as a semiquantitative analytical method for discriminating the molecular and amorphous states of gemfibrozil. Copyright © 2011 Elsevier B.V. All rights reserved.

Re-evaluation of differential phase contrast (DPC) in a scanning laser microscope using a split detector as an alternative to differential interference contrast (DIC) optics.

PubMed

Amos, W B; Reichelt, S; Cattermole, D M; Laufer, J

2003-05-01

In this paper, differential phase imaging (DPC) with transmitted light is implemented by adding a suitable detection system to a standard commercially available scanning confocal microscope. DPC, a long-established method in scanning optical microscopy, depends on detecting the intensity difference between opposite halves or quadrants of a split photodiode detector placed in an aperture plane. Here, DPC is compared with scanned differential interference contrast (DIC) using a variety of biological specimens and objective lenses of high numerical aperture. While DPC and DIC images are generally similar, DPC seems to have a greater depth of field. DPC has several advantages over DIC. These include low cost (no polarizing or strain-free optics are required), absence of a double scanning spot, electronically variable direction of shading and the ability to image specimens in plastic dishes where birefringence prevents the use of DIC. DPC is also here found to need 20 times less laser power at the specimen than DIC.

Correlation between differential renal function estimation using CT-based functional renal parenchymal volume and (99m)Tc - DTPA renal scan.

PubMed

Sarma, Debanga; Barua, Sasanka K; Rajeev, T P; Baruah, Saumar J

2012-10-01

Nuclear renal scan is currently the gold standard imaging study to determine differential renal function. We propose helical CT as single modality for both the anatomical and functional evaluation of kidney with impaired function. In the present study renal parenchymal volume is measured and percent total renal volume is used as a surrogate marker for differential renal function. The objective of this study is to correlate between differential renal function estimation using CT-based renal parenchymal volume measurement with differential renal function estimation using (99m)TC - DTPA renal scan. Twenty-one patients with unilateral obstructive uropathy were enrolled in this prospective comparative study. They were subjected to (99m)Tc - DTPA renal scan and 64 slice helical CT scan which estimates the renal volume depending on the reconstruction of arterial phase images followed by volume rendering and percent renal volume was calculated. Percent renal volume was correlated with percent renal function, as determined by nuclear renal scan using Pearson coefficient. RESULTS AND OBSERVATION: A strong correlation is observed between percent renal volume and percent renal function in obstructed units (r = 0.828, P < 0.001) as well as in nonobstructed units (r = 0.827, P < 0.001). There is a strong correlation between percent renal volume determined by CT scan and percent renal function determined by (99m)TC - DTPA renal scan both in obstructed and in normal units. CT-based percent renal volume can be used as a single radiological tests for both functional and anatomical assessment of impaired renal units.

A power compensated differential scanning calorimeter for protein stability characterization

DOE PAGES

Wang, Shuyu; Yu, Shifeng; Siedler, Michael; ...

2017-10-07

This study presented a power compensated MEMS differential scanning calorimeter (DSC) for protein stability characterization. In this microfabricated sensor, PDMS (Polydimethylsiloxane) and polyimide were used to construct the adiabatic chamber (1 μL) and temperature sensitive vanadium oxide was used as the thermistor material. A power compensation system was implemented to maintain the sample and reference at the same temperature. The resolution study and step response characterization indicated the high sensitivity (6 V/W) and low noise level (60 μk) of the device. The test with IgG1 antibody (mAb1) samples showed clear phase transitions and the data was confirmed to be reasonablemore » by comparing it with the results of commercial DSC’s test. Finally, this device used ~1uL sample amount and could complete the scanning process in 4 min, significantly increasing the throughput of the bimolecular thermodynamics study like drug formulation process.« less

Differential polarization laser scanning microscopy: biological applications

NASA Astrophysics Data System (ADS)

Steinbach, G.; Besson, F.; Pomozi, I.; Garab, G.

2005-09-01

With the aid of a differential polarization (DP) apparatus, developed in our laboratory and attached to our laser scanning confocal microscope, we can measure the magnitude and spatial distribution of 8 different DP quantities: linear and circular dichroism (LD&CD), linear and circular anisotropy of the emission (R and CPL, confocal), fluorescence detected dichroisms (FDLD&FDCD, confocal), linear birefringence (LB), and the degree of polarization of fluorescence emission (P, confocal). The attachment uses high frequency modulation and subsequent demodulation, via lock-in amplifier, of the detected intensity values, and records and displays pixel-by-pixel the measured DP quantity. These microscopic DP data carry important physical information on the molecular architecture of anisotropically organized samples. Microscopic DP measurements are thought to be of particular importance in biology. In most biological samples anisotropy is difficult to determine with conventional, macroscopic DP measurements and microscopic variations are of special significance. In this paper, we describe the method of LB imaging. Using magnetically oriented isolated chloroplasts trapped in polyacrylamide gel, we demonstrate that LB can be determined with high sensitivity and good spatial resolution. Granal thylakoid membranes in edge-aligned orientation exhibited strong LB, with large variations in its sign and magnitude. In face-aligned position LB was considerably weaker, and tended to vanish when averaged for the whole image. The strong local variations are attributed to the inherent heterogeneity of the membranes, i.e. to their internal differentiation into multilamellar, stacked membranes (grana), and single thylakoids (stroma membranes). Further details and applications of our DP-LSM will be published elsewhere.

Differentiating Amino Acid Residues and Side Chain Orientations in Peptides Using Scanning Tunneling Microscopy

PubMed Central

Claridge, Shelley A.; Thomas, John C.; Silverman, Miles A.; Schwartz, Jeffrey J.; Yang, Yanlian; Wang, Chen; Weiss, Paul S.

2014-01-01

Single-molecule measurements of complex biological structures such as proteins are an attractive route for determining structures of the large number of important biomolecules that have proved refractory to analysis through standard techniques such as X-ray crystallography and nuclear magnetic resonance. We use a custom-built low-current scanning tunneling microscope to image peptide structure at the single-molecule scale in a model peptide that forms β sheets, a structural motif common in protein misfolding diseases. We successfully differentiate between histidine and alanine amino acid residues, and further differentiate side chain orientations in individual histidine residues, by correlating features in scanning tunneling microscope images with those in energy-optimized models. Beta sheets containing histidine residues are used as a model system due to the role histidine plays in transition metal binding associated with amyloid oligomerization in Alzheimer’s and other diseases. Such measurements are a first step toward analyzing peptide and protein structures at the single-molecule level. PMID:24219245

Investigating Freezing Point Depression and Cirrus Cloud Nucleation Mechanisms Using a Differential Scanning Calorimeter

ERIC Educational Resources Information Center

Bodzewski, Kentaro Y.; Caylor, Ryan L.; Comstock, Ashley M.; Hadley, Austin T.; Imholt, Felisha M.; Kirwan, Kory D.; Oyama, Kira S.; Wise, Matthew E.

2016-01-01

A differential scanning calorimeter was used to study homogeneous nucleation of ice from micron-sized aqueous ammonium sulfate aerosol particles. It is important to understand the conditions at which these particles nucleate ice because of their connection to cirrus cloud formation. Additionally, the concept of freezing point depression, a topic…

Comparison of spray drying, electroblowing and electrospinning for preparation of Eudragit E and itraconazole solid dispersions.

PubMed

Sóti, Péter Lajos; Bocz, Katalin; Pataki, Hajnalka; Eke, Zsuzsanna; Farkas, Attila; Verreck, Geert; Kiss, Éva; Fekete, Pál; Vigh, Tamás; Wagner, István; Nagy, Zsombor K; Marosi, György

2015-10-15

Three solvent based methods: spray drying (SD), electrospinning (ES) and air-assisted electrospinning (electroblowing; EB) were used to prepare solid dispersions of itraconazole and Eudragit E. Samples with the same API/polymer ratios were prepared in order to make the three technologies comparable. The structure and morphology of solid dispersions were identified by scanning electron microscopy and solid phase analytical methods such as, X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and Raman chemical mapping. Moreover, the residual organic solvents of the solid products were determined by static headspace-gas chromatography/mass spectroscopy measurements and the wettability of samples was characterized by contact angle measurement. The pharmaceutical performance of the three dispersion type, evaluated by dissolution tests, proved to be very similar. According to XRPD and DSC analyses, made after the production, all the solid dispersions were free of any API crystal clusters but about 10 wt% drug crystallinity was observed after three months of storage in the case of the SD samples in contrast to the samples produced by ES and EB in which the polymer matrix preserved the API in amorphous state. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved Differential Ion Mobility Separations Using Linked Scans of Carrier Gas Composition and Compensation Field

NASA Astrophysics Data System (ADS)

Santiago, Brandon G.; Harris, Rachel A.; Isenberg, Samantha L.; Ridgeway, Mark E.; Pilo, Alice L.; Kaplan, Desmond A.; Glish, Gary L.

2015-07-01

Differential ion mobility spectrometry (DIMS) separates ions based on differences in their mobilities in low and high electric fields. When coupled to mass spectrometric analyses, DIMS has the ability to improve signal-to-background by eliminating isobaric and isomeric compounds for analytes in complex mixtures. DIMS separation power, often measured by resolution and peak capacity, can be improved through increasing the fraction of helium in the nitrogen carrier gas. However, because the mobility of ions is higher in helium, a greater number of ions collide with the DIMS electrodes or housing, yielding losses in signal intensity. To take advantage of the benefits of helium addition on DIMS separations and reduce ion losses, linked scans were developed. In a linked scan the helium content of the carrier gas is reduced as the compensation field is increased. Linked scans were compared with conventional compensation field scans with constant helium content for the protein ubiquitin and a tryptic digest of bovine serum albumin (BSA). Linked scans yield better separation of ubiquitin charge states and enhanced peak capacities for the analysis of BSA compared with compensation field scans with constant helium carrier gas percentages. Linked scans also offer improved signal intensity retention in comparison to compensation field scans with constant helium percentages in the carrier gas.

Low cost, microcontroller based heating device for multi-wavelength differential scanning fluorimetry.

PubMed

Hoeser, Jo; Gnandt, Emmanuel; Friedrich, Thorsten

2018-01-23

Differential scanning fluorimetry is a popular method to estimate the stability of a protein in distinct buffer conditions by determining its 'melting point'. The method requires a temperature controlled fluorescence spectrometer or a RT-PCR machine. Here, we introduce a low-budget version of a microcontroller based heating device implemented into a 96-well plate reader that is connected to a standard fluorescence spectrometer. We demonstrate its potential to determine the 'melting point' of soluble and membranous proteins at various buffer conditions.

Evaluation of the interaction of coumarins with biomembrane models studied by differential scanning calorimetry and Langmuir-Blodgett techniques.

PubMed

Sarpietro, Maria Grazia; Giuffrida, Maria Chiara; Ottimo, Sara; Micieli, Dorotea; Castelli, Francesco

2011-04-25

Three coumarins, scopoletin (1), esculetin (2), and esculin (3), were investigated by differential scanning calorimetry and Langmuir-Blodgett techniques to gain information about the interaction of these compounds with cellular membranes. Phospholipids assembled as multilamellar vesicles or monolayers (at the air-water interface) were used as biomembrane models. Differential scanning calorimetry was employed to study the interaction of these coumarins with multilamellar vesicles and to evaluate their absorption by multilamellar vesicles. These experiments indicated that 1-3 interact in this manner to different extents. The Langmuir-Blodgett technique was used to study the effect of these coumarins on the organization of phospholipids assembled as a monolayer. The data obtained were in agreement with those obtained in the calorimetric experiments.

Method and apparatus for differential spectroscopic atomic-imaging using scanning tunneling microscopy

DOEpatents

Kazmerski, Lawrence L.

1990-01-01

A Method and apparatus for differential spectroscopic atomic-imaging is disclosed for spatial resolution and imaging for display not only individual atoms on a sample surface, but also bonding and the specific atomic species in such bond. The apparatus includes a scanning tunneling microscope (STM) that is modified to include photon biasing, preferably a tuneable laser, modulating electronic surface biasing for the sample, and temperature biasing, preferably a vibration-free refrigerated sample mounting stage. Computer control and data processing and visual display components are also included. The method includes modulating the electronic bias voltage with and without selected photon wavelengths and frequency biasing under a stabilizing (usually cold) bias temperature to detect bonding and specific atomic species in the bonds as the STM rasters the sample. This data is processed along with atomic spatial topography data obtained from the STM raster scan to create a real-time visual image of the atoms on the sample surface.

Measurement of ultrasonic fields in transparent media using a scanning differential interferometer

NASA Technical Reports Server (NTRS)

Dockery, G. D.; Claus, R. O.

1983-01-01

An experimental system for the detection of three dimensional acoustic fields in optically transparent media using a dual beam differential interferometer is described. In this system, two coherent, parallel, focused laser beams are passed through the specimen and the interference fringe pattern which results when these beams are combined shifts linearly by an amount which is related to the optical pathlength difference between the two beams. It is shown that for small signals, the detector output is directly proportional to the amplitude of the acoustic field integrated along the optical beam path through the specimen. A water tank and motorized optical platform were constructed to allow these dual beams to be scanned through an ultrasonic field generated by a piezoelectric transducer at various distances from the transducer. Scan data for the near, Fresnel, and far zones of a uniform, circular transducer are presented and an algorithm for constructing the radial field profile from this integrated optical data, assuming cylindrical symmetry, is described.

Irreversible denaturation of maltodextrin glucosidase studied by differential scanning calorimetry, circular dichroism, and turbidity measurements.

PubMed

Goyal, Megha; Chaudhuri, Tapan K; Kuwajima, Kunihiro

2014-01-01

Thermal denaturation of Escherichia coli maltodextrin glucosidase was studied by differential scanning calorimetry, circular dichroism (230 nm), and UV-absorption measurements (340 nm), which were respectively used to monitor heat absorption, conformational unfolding, and the production of solution turbidity. The denaturation was irreversible, and the thermal transition recorded at scan rates of 0.5-1.5 K/min was significantly scan-rate dependent, indicating that the thermal denaturation was kinetically controlled. The absence of a protein-concentration effect on the thermal transition indicated that the denaturation was rate-limited by a mono-molecular process. From the analysis of the calorimetric thermograms, a one-step irreversible model well represented the thermal denaturation of the protein. The calorimetrically observed thermal transitions showed excellent coincidence with the turbidity transitions monitored by UV-absorption as well as with the unfolding transitions monitored by circular dichroism. The thermal denaturation of the protein was thus rate-limited by conformational unfolding, which was followed by a rapid irreversible formation of aggregates that produced the solution turbidity. It is thus important to note that the absence of the protein-concentration effect on the irreversible thermal denaturation does not necessarily means the absence of protein aggregation itself. The turbidity measurements together with differential scanning calorimetry in the irreversible thermal denaturation of the protein provided a very effective approach for understanding the mechanisms of the irreversible denaturation. The Arrhenius-equation parameters obtained from analysis of the thermal denaturation were compared with those of other proteins that have been reported to show the one-step irreversible thermal denaturation. Maltodextrin glucosidase had sufficiently high kinetic stability with a half-life of 68 days at a physiological temperature (37°C).

Examination of water phase transitions in Loblolly pine and cell wall components by differential scanning calorimetry

Treesearch

Samuel L. Zelinka; Michael J. Lambrecht; Samuel V. Glass; Alex C. Wiedenhoeft; Daniel J. Yelle

2012-01-01

This paper examines phase transformations of water in wood and isolated wood cell wall components using differential scanning calorimetry with the purpose of better understanding "Type II water" or "freezable bound water" that has been reported for cellulose and other hydrophilic polymers. Solid loblolly pine (Pinus taeda...

Immersion ultrasonography: simultaneous A-scan and B-scan.

PubMed

Coleman, D J; Dallow, R L; Smith, M E

1979-01-01

In eyes with opaque media, ophthalmic ultrasound provides a unique source of information that can dramatically affect the course of patient management. In addition, when an ocular abnormality can be visualized, ultrasonography provides information that supplements and complements other diagnostic testing. It provides documentation and differentiation of abnormal states, such as vitreous hemorrhage and intraocular tumor, as well as differentiation of orbital tumors from inflammatory causes of exophthalmos. Additional capabilities of ultrasound are biometric determinations for calculation of intraocular lens implant powers and drug-effectiveness studies. Maximal information is derived from ultrasonography when A-scan and B-scan techniques are employed simultaneously. Flexibility of electronics, variable-frequency transducers, and the use of several different manual scanning patterns aid in detection and interpretation of results. The immersion system of ultrasonography provides these features optimally.

Differential scanning calorimetry of the effects of temperature and humidity on phenol-formaldehyde resin cure

Treesearch

X.-M. Wang; B. Riedl; A.W. Christiansen; R.L. Geimer

1994-01-01

Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31...

Preparation and characterization of adefovir dipivoxil-stearic acid cocrystal with enhanced physicochemical properties.

PubMed

Seo, Jeong-Woong; Hwang, Kyu-Min; Lee, Sung-Hoon; Kim, Dong-Wook; Park, Eun-Seok

2017-06-11

The objectives of this study were to prepare cocrystal composed of adefovir dipivoxil (AD) and stearic acid (SA) and to investigate the enhanced properties of the cocrystal. The cocrystal was prepared by antisolvent precipitation and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRPD), and differential scanning calorimetry (DSC). The enhanced properties were evaluated by dissolution testing, permeability studies, and powder rheology analysis. The AD raw material has a cuboid-like crystal and the cocrystal has a needle shape. In the FT-IR study, there were bathochromic shifts caused by the hydrogen bonding. The melting point of the cocrystal was 52.9 °C, which was lower than that of AD. The XRPD pattern also had distinct differences, supporting the formation of a new crystalline form. The cocrystal showed changes in the lattice energy and the solvation strength, which caused an enhanced dissolution. The permeability was increased due to the SA, which acts as a P-gp inhibitor. The tabletability was enhanced due to the altered crystal habit. In conclusion, cocrystal containing AD and SA was successfully prepared, presenting advantages such as enhanced solubility, tabletability, and permeability. The use of the cocrystal is a desirable approach for the improved physicochemical properties.

A novel hot-melt extrusion formulation of albendazole for increasing dissolution properties.

PubMed

Martinez-Marcos, Laura; Lamprou, Dimitrios A; McBurney, Roy T; Halbert, Gavin W

2016-02-29

The main aim of the research focused on the production of hot-melt extrusion (HME) formulations with increased dissolution properties of albendazole (ABZ). Therefore, HME was applied as a continuous manufacturing technique to produce amorphous solid dispersions of the poorly water soluble drug ABZ combined with the polymer matrix polyvinylpyrrolidone PVP K12. HME formulations of ABZ-PVP K12 comprised a drug content of 1%, 5% and 10% w/w. The main analytical characterisation techniques used were scanning electron microscopy (SEM), micro-computed tomography (μ-CT), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and dissolution profile studies. The application of SEM, XRPD and DSC evidenced drug physical transformation from crystalline to amorphous state and therefore, the achievement of an amorphous solid dispersion. The introduction of a novel technique, μ-CT, to characterise the internal structure of these materials revealed key information regarding materials distribution and void content. Dissolution profile studies evidenced a high increase in drug release profile compared to pure ABZ. These promising results can lead to a great enhancement of the oral bioavailability of ABZ dosage forms. Therefore, HME is a potential continuous manufacturing technique to overcome ABZ poor solubility properties and lead to a significant increase in the therapeutic effect. Copyright © 2016 Elsevier B.V. All rights reserved.

Using a Differential Scanning Calorimeter to Teach Phase Equilibria to Students of Igneous and Metamorphic Petrology

ERIC Educational Resources Information Center

Maria, Anton H.; Millam, Evan L.; Wright, Carrie L.

2011-01-01

As an aid for teaching phase equilibria to undergraduate students of igneous and metamorphic petrology, we have designed a laboratory exercise that allows them to create a phase diagram from data produced by differential scanning calorimetry. By preparing and analyzing samples of naphthalene and phenanthrene, students acquire hands-on insight into…

Irreversible Denaturation of Maltodextrin Glucosidase Studied by Differential Scanning Calorimetry, Circular Dichroism, and Turbidity Measurements

PubMed Central

Goyal, Megha; Chaudhuri, Tapan K.; Kuwajima, Kunihiro

2014-01-01

Thermal denaturation of Escherichia coli maltodextrin glucosidase was studied by differential scanning calorimetry, circular dichroism (230 nm), and UV-absorption measurements (340 nm), which were respectively used to monitor heat absorption, conformational unfolding, and the production of solution turbidity. The denaturation was irreversible, and the thermal transition recorded at scan rates of 0.5–1.5 K/min was significantly scan-rate dependent, indicating that the thermal denaturation was kinetically controlled. The absence of a protein-concentration effect on the thermal transition indicated that the denaturation was rate-limited by a mono-molecular process. From the analysis of the calorimetric thermograms, a one-step irreversible model well represented the thermal denaturation of the protein. The calorimetrically observed thermal transitions showed excellent coincidence with the turbidity transitions monitored by UV-absorption as well as with the unfolding transitions monitored by circular dichroism. The thermal denaturation of the protein was thus rate-limited by conformational unfolding, which was followed by a rapid irreversible formation of aggregates that produced the solution turbidity. It is thus important to note that the absence of the protein-concentration effect on the irreversible thermal denaturation does not necessarily means the absence of protein aggregation itself. The turbidity measurements together with differential scanning calorimetry in the irreversible thermal denaturation of the protein provided a very effective approach for understanding the mechanisms of the irreversible denaturation. The Arrhenius-equation parameters obtained from analysis of the thermal denaturation were compared with those of other proteins that have been reported to show the one-step irreversible thermal denaturation. Maltodextrin glucosidase had sufficiently high kinetic stability with a half-life of 68 days at a physiological temperature (37°C). PMID

Rapid and Adaptable Measurement of Protein Thermal Stability by Differential Scanning Fluorimetry: Updating a Common Biochemical Laboratory Experiment

ERIC Educational Resources Information Center

Johnson, R. Jeremy; Savas, Christopher J.; Kartje, Zachary; Hoops, Geoffrey C.

2014-01-01

Measurement of protein denaturation and protein folding is a common laboratory technique used in undergraduate biochemistry laboratories. Differential scanning fluorimetry (DSF) provides a rapid, sensitive, and general method for measuring protein thermal stability in an undergraduate biochemistry laboratory. In this method, the thermal…

Scanning the genome for gene single nucleotide polymorphisms involved in adaptive population differentiation in white spruce

PubMed Central

Namroud, Marie-Claire; Beaulieu, Jean; Juge, Nicolas; Laroche, Jérôme; Bousquet, Jean

2008-01-01

Conifers are characterized by a large genome size and a rapid decay of linkage disequilibrium, most often within gene limits. Genome scans based on noncoding markers are less likely to detect molecular adaptation linked to genes in these species. In this study, we assessed the effectiveness of a genome-wide single nucleotide polymorphism (SNP) scan focused on expressed genes in detecting local adaptation in a conifer species. Samples were collected from six natural populations of white spruce (Picea glauca) moderately differentiated for several quantitative characters. A total of 534 SNPs representing 345 expressed genes were analysed. Genes potentially under natural selection were identified by estimating the differentiation in SNP frequencies among populations (FST) and identifying outliers, and by estimating local differentiation using a Bayesian approach. Both average expected heterozygosity and population differentiation estimates (HE = 0.270 and FST = 0.006) were comparable to those obtained with other genetic markers. Of all genes, 5.5% were identified as outliers with FST at the 95% confidence level, while 14% were identified as candidates for local adaptation with the Bayesian method. There was some overlap between the two gene sets. More than half of the candidate genes for local adaptation were specific to the warmest population, about 20% to the most arid population, and 15% to the coldest and most humid higher altitude population. These adaptive trends were consistent with the genes’ putative functions and the divergence in quantitative traits noted among the populations. The results suggest that an approach separating the locus and population effects is useful to identify genes potentially under selection. These candidates are worth exploring in more details at the physiological and ecological levels. PMID:18662225

Polymorphism of Alprazolam (Xanax): a review of its crystalline phases and identification, crystallographic characterization, and crystal structure of a new polymorph (form III).

PubMed

de Armas, Héctor Novoa; Peeters, Oswald M; Van den Mooter, Guy; Blaton, Norbert

2007-05-01

A new polymorphic form of Alprazolam (Xanax), 8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo-[4,3-alpha][1,4]benzodiazepine, C(17)H(13)ClN(4), has been investigated by means of X-ray powder diffraction (XRPD), single crystal X-ray diffraction, and differential scanning calorimetry (DSC). This polymorphic form (form III) was obtained during DSC experiments after the exothermic recrystallization of the melt of form I. The crystal unit cell dimensions for form III were determined from diffractometer methods. The monoclinic unit cell found for this polymorph using XRPD after indexing the powder diffractogram was confirmed by the cell parameters obtained from single crystal X-ray diffractometry on a crystal isolated from the DSC pans. The single crystal unit cell parameters are: a = 28.929(9), b = 13.844(8), c = 7.361(3) angstroms, beta = 92.82(3) degrees , V = 2944(2) angstroms(3), Z = 8, space group P2(1) (No.4), Dx = 1.393 Mg/m(3). The structure obtained from single crystal X-ray diffraction was used as initial model for Rietveld refinement on the powder diffraction data of form III. The temperature phase transformations of alprazolam were also studied using high temperature XRPD. A review of the different phases available in the Powder Diffraction File (PDF) database for this drug is described bringing some clarification and corrections. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Thermal Properties of Organic Hydrocarbons

ERIC Educational Resources Information Center

D'Amelia, Ronald; Franks, Thomas; Nirode, William F.

2007-01-01

In first-year general chemistry undergraduate courses, thermodynamics and thermal properties such as melting points and changes in enthalpy ([Delta]H) and entropy ([Delta]S) of phase changes are frequently discussed. Typically, classical calorimetric methods of analysis are used to determine [Delta]H of reactions. Differential scanning calorimetry…

Solid-state evaluation and polymorphic quantification of venlafaxine hydrochloride raw materials using the Rietveld method.

PubMed

Bernardi, Larissa S; Ferreira, Fábio F; Cuffini, Silvia L; Campos, Carlos E M; Monti, Gustavo A; Kuminek, Gislaine; Oliveira, Paulo R; Cardoso, Simone G

2013-12-15

Venlafaxine hydrochloride (VEN) is an antidepressant drug widely used for the treatment of depression. The purpose of this study was to carry out the preparation and solid state characterization of the pure polymorphs (Forms 1 and 2) and the polymorphic identification and quantification of four commercially-available VEN raw materials. These two polymorphic forms were obtained from different crystallization methods and characterized by X-ray Powder Diffraction (XRPD), Diffuse Reflectance Infrared Fourier Transform (DRIFT), Raman Spectroscopy (RS), liquid and solid state Nuclear Magnetic Resonance (NMR and ssNMR) spectroscopies, Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) techniques. The main differences were observed by DSC and XRPD and the latter was chosen as the standard technique for the identification and quantification studies in combination with the Rietveld method for the commercial raw materials (VEN1-VEN4) acquired from different manufacturers. Additionally Form 1 and Form 2 can be clearly distinguished from their (13)C ssNMR spectra. Through the analysis, it was possible to conclude that VEN1 and VEN2 were composed only of Form 1, while VEN3 and VEN4 were a mixture of Forms 1 and 2. Additionally, the Rietveld refinement was successfully applied to quantify the polymorphic ratio for VEN3 and VEN4. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluation of optimized magnetic resonance perfusion imaging scanning time window after contrast agent injection for differentiating benign and malignant breast lesions

PubMed Central

Dong, Jie; Wang, Dawei; Ma, Zhenshen; Deng, Guodong; Wang, Lanhua; Zhang, Jiandong

2017-01-01

The aim of the study was evaluate the 3.0 T magnetic resonance (MR) perfusion imaging scanning time window following contrast injection for differentiating benign and malignant breast lesions and to determine the optimum scanning time window for increased scanner usage efficiency and reduced diagnostic adverse risk factors. A total of 52 women with breast abnormalities were selected for conventional MR imaging and T1 dynamic-enhanced imaging. Quantitative parameters [volume transfer constant (Ktrans), rate constant (Kep) and extravascular extracellular volume fraction (Ve)] were calculated at phases 10, 20, 30, 40 and 50, which represented time windows at 5, 10, 15, 20 and 25 min, respectively, following injection of contrast agent. The association of the parameters at different phases with benign and malignant tumor diagnosis was analyzed. MR perfusion imaging was verified as an effective modality in the diagnosis of breast malignancies and the best scanning time window was identified: i) Values of Ktrans and Kep at all phases were statistically significant in differentiating benign and malignant tumors (P<0.05), while the value of Ve had statistical significance only at stage 10, but not at any other stages (P>0.05); ii) values of Ve in benign tumors increased with phase number, but achieved no obvious changes at different phases in malignant tumors; iii) the optimum scanning time window of breast perfusion imaging with 3.0 T MR was between phases 10 and 30 (i.e., between 5 and 15 min after contrast agent injection). The variation trend of Ve values at different phases may serve as a diagnostic reference for differentiating benign and malignant breast abnormalities. The most efficient scanning time window was indicated to be 5 min after contrast injection, based on the observation that the Ve value only had statistical significance in diagnosis at stage 10. However, the optimal scanning time window is from 5 to 15 min following the injection of contrast agent

Evaluation of optimized magnetic resonance perfusion imaging scanning time window after contrast agent injection for differentiating benign and malignant breast lesions.

PubMed

Dong, Jie; Wang, Dawei; Ma, Zhenshen; Deng, Guodong; Wang, Lanhua; Zhang, Jiandong

2017-03-01

The aim of the study was evaluate the 3.0 T magnetic resonance (MR) perfusion imaging scanning time window following contrast injection for differentiating benign and malignant breast lesions and to determine the optimum scanning time window for increased scanner usage efficiency and reduced diagnostic adverse risk factors. A total of 52 women with breast abnormalities were selected for conventional MR imaging and T1 dynamic-enhanced imaging. Quantitative parameters [volume transfer constant (K trans ), rate constant (K ep ) and extravascular extracellular volume fraction (V e )] were calculated at phases 10, 20, 30, 40 and 50, which represented time windows at 5, 10, 15, 20 and 25 min, respectively, following injection of contrast agent. The association of the parameters at different phases with benign and malignant tumor diagnosis was analyzed. MR perfusion imaging was verified as an effective modality in the diagnosis of breast malignancies and the best scanning time window was identified: i) Values of K trans and K ep at all phases were statistically significant in differentiating benign and malignant tumors (P<0.05), while the value of V e had statistical significance only at stage 10, but not at any other stages (P>0.05); ii) values of V e in benign tumors increased with phase number, but achieved no obvious changes at different phases in malignant tumors; iii) the optimum scanning time window of breast perfusion imaging with 3.0 T MR was between phases 10 and 30 (i.e., between 5 and 15 min after contrast agent injection). The variation trend of V e values at different phases may serve as a diagnostic reference for differentiating benign and malignant breast abnormalities. The most efficient scanning time window was indicated to be 5 min after contrast injection, based on the observation that the V e value only had statistical significance in diagnosis at stage 10. However, the optimal scanning time window is from 5 to 15 min following the injection of

Functional imaging in differentiating bronchial masses: an initial experience with a combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan.

PubMed

Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh

2009-10-01

To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.

Removal of Differential Capacitive Interferences in Fast-Scan Cyclic Voltammetry.

PubMed

Johnson, Justin A; Hobbs, Caddy N; Wightman, R Mark

2017-06-06

Due to its high spatiotemporal resolution, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes enables the localized in vivo monitoring of subsecond fluctuations in electroactive neurotransmitter concentrations. In practice, resolution of the analytical signal relies on digital background subtraction for removal of the large current due to charging of the electrical double layer as well as surface faradaic reactions. However, fluctuations in this background current often occur with changes in the electrode state or ionic environment, leading to nonspecific contributions to the FSCV data that confound data analysis. Here, we both explore the origin of such shifts seen with local changes in cations and develop a model to account for their shape. Further, we describe a convolution-based method for removal of the differential capacitive contributions to the FSCV current. The method relies on the use of a small-amplitude pulse made prior to the FSCV sweep that probes the impedance of the system. To predict the nonfaradaic current response to the voltammetric sweep, the step current response is differentiated to provide an estimate of the system's impulse response function and is used to convolute the applied waveform. The generated prediction is then subtracted from the observed current to the voltammetric sweep, removing artifacts associated with electrode impedance changes. The technique is demonstrated to remove select contributions from capacitive characteristics changes of the electrode both in vitro (i.e., in flow-injection analysis) and in vivo (i.e., during a spreading depression event in an anesthetized rat).

Differential Scanning Calorimetric (DSC) Analysis of Rotary Nickel-Titanium (NiTi) Endodontic File (RNEF)

NASA Astrophysics Data System (ADS)

Wu, Ray Chun Tung; Chung, C. Y.

2012-12-01

To determine the variation of A f along the axial length of rotary nickel-titanium endodontic files (RNEF). Three commercial brands of 4% taper RNEF: GTX (#20, 25 mm, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), K3 (#25, 25 mm) and TF (Twisted File #25, 27 mm) (Sybron Kerr, Orange, CA, USA) were cut into segments at 4 mm increment from the working tip. Regional specimens were measured for differential heat-flow over thermal cycling, generally with continuous heating or cooling (5 °C/min) and 5 min hold at set temperatures (start, finish temperatures): GTX: -55, 90 °C; K3: -55, 45 °C; TF: -55, 60 °C; using differential scanning calorimeter. This experiment demonstrated regional differences in A f along the axial length of GTX and K3 files. Similar variation was not obvious in the TF samples. A contributory effect of regional difference in strain-hardening due to grinding and machining during manufacturing is proposed.

Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

NASA Astrophysics Data System (ADS)

Nokhodchi, A.; Bolourtchian, N.; Dinarvand, R.

2005-02-01

Carbamazepine (CBZ) crystals were grown from pure ethanol solutions containing various additives (PEG 4000, PVP K30 or Tween 80). Physical characteristics of the crystals were studied for the morphology of crystals using scanning electron microscope, for the identification of polymorphism by X-ray powder diffraction (XRPD) and FT-IR, and for thermodynamic properties using differential scanning calorimetery (DSC). The dissolution behaviour of various carbamazepine crystals was also studied by dissolution apparatus II at pH 7.4 containing 1% sodium lauryl sulphate (SLS). The scanning electron micrograph (SEM) studies showed that the presence of the additives in the solutions growth medium affected the morphology and size of carbamazepine crystals. SEMs of untreated and treated carbamazepine crystals obtained from alcohol containing PEG 4000, PVP K30 or Tween 80 showed that the crystal shape of untreated carbamazepine is flaky or thin plate-like, whereas the crystals obtained from alcohol containing no additive, PEG 4000, PVP K30 or Tween 80 are polyhedral prismatic, block-shaped, polyhedral or hexagonal, respectively. XRPD, FT-IR and DSC results showed that the untreated CBZ was form III and recrystallization of CBZ in the absence or presence of the additives did not cause any polymorphic changes. The results showed that the higher dissolution rate and compact strength were observed for the crystals obtained in the presence of PVP K30. The presence of the additives in crystallization medium alters crystal morphology of carbamazepine, but only the samples crystallized in the presence of PVP K30 showed an improvement in dissolution rate and tensile strength.

Step-scan T cell-based differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS) for detection of ambient air contaminants

NASA Astrophysics Data System (ADS)

Liu, Lixian; Mandelis, Andreas; Huan, Huiting; Melnikov, Alexander

2016-10-01

A step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS) using a commercial FTIR spectrometer was developed theoretically and experimentally for air contaminant monitoring. The configuration comprises two identical, small-size and low-resonance-frequency T cells satisfying the conflicting requirements of low chopping frequency and limited space in the sample compartment. Carbon dioxide (CO2) IR absorption spectra were used to demonstrate the capability of the DFTIR-PAS method to detect ambient pollutants. A linear amplitude response to CO2 concentrations from 100 to 10,000 ppmv was observed, leading to a theoretical detection limit of 2 ppmv. The differential mode was able to suppress the coherent noise, thereby imparting the DFTIR-PAS method with a better signal-to-noise ratio and lower theoretical detection limit than the single mode. The results indicate that it is possible to use step-scan DFTIR-PAS with T cells as a quantitative method for high sensitivity analysis of ambient contaminants.

Magnetic-field-controlled negative differential conductance in scanning tunneling spectroscopy of graphene npn junction resonators

NASA Astrophysics Data System (ADS)

Li, Si-Yu; Liu, Haiwen; Qiao, Jia-Bin; Jiang, Hua; He, Lin

2018-03-01

Negative differential conductance (NDC), characterized by the decreasing current with increasing voltage, has attracted continuous attention for its various novel applications. The NDC typically exists in a certain range of bias voltages for a selected system and controlling the regions of NDC in curves of current versus voltage (I -V ) is experimentally challenging. Here, we demonstrate a magnetic-field-controlled NDC in scanning tunneling spectroscopy of graphene npn junction resonators. The magnetic field not only can switch on and off the NDC, but also can continuously tune the regions of the NDC in the I -V curves. In the graphene npn junction resonators, magnetic fields generate sharp and pronounced Landau-level peaks with the help of the Klein tunneling of massless Dirac fermions. A tip of scanning tunneling microscope induces a relatively shift of the Landau levels in graphene beneath the tip. Tunneling between the misaligned Landau levels results in the magnetic-field-controlled NDC.

The oxidation of aluminum at high temperature studied by Thermogravimetric Analysis and Differential Scanning Calorimetry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coker, Eric Nicholas

2013-10-01

The oxidation in air of high-purity Al foil was studied as a function of temperature using Thermogravimetric Analysis with Differential Scanning Calorimetry (TGA/DSC). The rate and/or extent of oxidation was found to be a non-linear function of the temperature. Between 650 and 750 ÀC very little oxidation took place; at 850 ÀC oxidation occurred after an induction period, while at 950 ÀC oxidation occurred without an induction period. At oxidation temperatures between 1050 and 1150 ÀC rapid passivation of the surface of the aluminum foil occurred, while at 1250 ÀC and above, an initial rapid mass increase was observed, followedmore » by a more gradual increase in mass. The initial rapid increase was accompanied by a significant exotherm. Cross-sections of oxidized specimens were characterized by scanning electron microscopy (SEM); the observed alumina skin thicknesses correlated qualitatively with the observed mass increases.« less

Differentiation of Aedes aegypti and Aedes notoscriptus (Diptera: Culicidae) eggs using scanning electron microscopy.

PubMed

Faull, Katherine J; Williams, Craig R

2016-05-01

Aedes notoscriptus and Aedes aegypti are both peri-domestic, invasive container-breeding mosquitoes. While the two potential arboviral vectors are bionomically similar, their sympatric distribution in Australia is limited. In this study, analyses of Ae. aegypti and Ae. notoscriptus eggs were enabled using scanning electron microscopy. Significant variations in egg length to width ratio and outer chorionic cell field morphology between Ae. aegypti and Ae. notoscriptus enabled distinction of the two species. Intraspecific variations in cell field morphology also enabled differentiation of the separate populations of both species, highlighting regional and global variation. Our study provides a comprehensive comparative analysis of inter- and intraspecific egg morphological and morphometric variation between two invasive container-breeding mosquitoes. The results indicate a high degree of intraspecific variation in Ae. notoscriptus egg morphology when compared to the eggs of Ae. aegypti. Comparative morphological analyses of Ae. aegypti and Ae. notoscriptus egg attributes using SEM allows differentiation of the species and may be helpful in understanding egg biology in relation to biotope of origin. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sonochemical synthesis and characterization of a novel hetro-binuclear metal organic nano polymer based on picolinic acid ligand

NASA Astrophysics Data System (ADS)

Hayati, Payam; Souri, Bagher; Rezvani, Ali Reza; Morsali, Ali; Gutierrez, Angel

2017-12-01

Nanoparticles of one new lead and K coordination polymer (CP), {[Pb6(pyc)6(N3)7K].½H2O}n (1) Hpyc = picolinic acid ligand, has been synthesized by use of a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FTIR) spectroscopy and elemental analyses. The single crystal X-ray data of compound 1 imply that the Pb ion is seven coordinated. The thermal stability of compound 1 has been studied by thermogravimetric (TG) and differential scanning calorimetry (DSC). The role of temperature, reaction time and ultrasound irradiation power on the size and morphfology of the nano-structured compound obtained from 1, have been investigated. Results indicate that an increase of temperature and sonication power and a decrease in time reaction led to a decrease of particle size.

Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans.

PubMed

Okada, Kazunori; Rysavy, Steven; Flores, Arturo; Linguraru, Marius George

2015-04-01

This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon's state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon's conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.

Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okada, Kazunori, E-mail: kazokada@sfsu.edu; Rysavy, Steven; Flores, Arturo

Purpose: This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. Methods: The proposed semiautomatic solutionmore » combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. Results: A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon’s state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Conclusions: Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon’s conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.« less

Laboratory Annealing Experiments Of Refractory Silicate Grain Analogs Using Differential Scanning Calorimetry

NASA Technical Reports Server (NTRS)

Kimura, Yuki; Nuth, Joseph A., III; Tsukamota, Katsuo; Kaito, Chihiro

2010-01-01

Exothermic reactions during the annealing of laboratory synthesized amorphous magnesium-bearing silicate particles used as grain analogs of cosmic dust were detected by differential scanning calorimetry (DSC) in air. With infrared spectroscopy and transmission electron microscopy, we show that cosmic dust could possibly undergo fusion to larger particles, with oxidation of magnesium silicide and crystallization of forsterite as exothermic reactions in the early solar system. The reactions begin at approximately 425, approximately 625, and approximately 1000 K, respectively, and the reaction energies (enthalpies) are at least 727, 4151, and 160.22 J per gram, respectively. During the crystallization of forsterite particles, the spectral evolution of the 10 micrometer feature from amorphous to crystalline was observed to begin at lower temperature than the crystallization temperature of 1003 K. During spectral evolution at lower temperature, nucleation and/or the formation of nanocrystallites of forsterite at the surface of the grain analogs was observed.

Resolving glass transition in Te-based phase-change materials by modulated differential scanning calorimetry

NASA Astrophysics Data System (ADS)

Chen, Yimin; Mu, Sen; Wang, Guoxiang; Shen, Xiang; Wang, Junqiang; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua; Wang, Rongping

2017-10-01

Glass transitions of Te-based phase-change materials (PCMs) were studied by modulated differential scanning calorimetry. It was found that both Ge2Sb2Te5 and GeTe are marginal glass formers with ΔT (= T x - T g) less than 2.1 °C when the heating rate is below 3 °C min-1. The fragilities of Ge2Sb2Te5 and GeTe can be estimated as 46.0 and 39.7, respectively, around the glass transition temperature, implying that a fragile-to-strong transition would be presented in such Te-based PCMs. The above results provide direct experimental evidence to support the investigation of crystallization kinetics in supercooled liquid PCMs.

Slit-scanning differential phase-contrast mammography: first experimental results

NASA Astrophysics Data System (ADS)

Roessl, Ewald; Daerr, Heiner; Koehler, Thomas; Martens, Gerhard; van Stevendaal, Udo

2014-03-01

The demands for a large field-of-view (FOV) and the stringent requirements for a stable acquisition geometry rank among the major obstacles for the translation of grating-based, differential phase-contrast techniques from the laboratory to clinical applications. While for state-of-the-art Full-Field-Digital Mammography (FFDM) FOVs of 24 cm x 30 cm are common practice, the specifications for mechanical stability are naturally derived from the detector pixel size which ranges between 50 and 100 μm. However, in grating-based, phasecontrast imaging, the relative placement of the gratings in the interferometer must be guaranteed to within micro-meter precision. In this work we report on first experimental results on a phase-contrast x-ray imaging system based on the Philips MicroDose L30 mammography unit. With the proposed approach we achieve a FOV of about 65 mm x 175 mm by the use of the slit-scanning technique. The demand for mechanical stability on a micrometer scale was relaxed by the specific interferometer design, i.e., a rigid, actuator-free mount of the phase-grating G1 with respect to the analyzer-grating G2 onto a common steel frame. The image acquisition and formation processes are described and first phase-contrast images of a test object are presented. A brief discussion of the shortcomings of the current approach is given, including the level of remaining image artifacts and the relatively inefficient usage of the total available x-ray source output.

Applications of high pressure differential scanning calorimetry to aviation fuel thermal stability research

NASA Technical Reports Server (NTRS)

Neveu, M. C.; Stocker, D. P.

1985-01-01

High pressure differential scanning calorimetry (DSC) was studied as an alternate method for performing high temperature fuel thermal stability research. The DSC was used to measure the heat of reaction versus temperature of a fuel sample heated at a programmed rate in an oxygen pressurized cell. Pure hydrocarbons and model fuels were studied using typical DSC operating conditions of 600 psig of oxygen and a temperature range from ambient to 500 C. The DSC oxidation onset temperature was determined and was used to rate the fuels on thermal stability. Kinetic rate constants were determined for the global initial oxidation reaction. Fuel deposit formation is measured, and the high temperature volatility of some tetralin deposits is studied by thermogravimetric analysis. Gas chromatography and mass spectrometry are used to study the chemical composition of some DSC stressed fuels.

Differential scanning calorimetry: An invaluable tool for a detailed thermodynamic characterization of macromolecules and their interactions

PubMed Central

Chiu, Michael H.; Prenner, Elmar J.

2011-01-01

Differential Scanning Calorimetry (DSC) is a highly sensitive technique to study the thermotropic properties of many different biological macromolecules and extracts. Since its early development, DSC has been applied to the pharmaceutical field with excipient studies and DNA drugs. In recent times, more attention has been applied to lipid-based drug delivery systems and drug interactions with biomimetic membranes. Highly reproducible phase transitions have been used to determine values, such as, the type of binding interaction, purity, stability, and release from a drug delivery mechanism. This review focuses on the use of DSC for biochemical and pharmaceutical applications. PMID:21430954

Detection of a new 'nematic-like' phase in liquid crystal-amphiphile mixture by differential scanning calorimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dan, Kaustabh, E-mail: kaustabhdan@gmail.com; Roy, Madhusudan, E-mail: kaustabhdan@gmail.com; Datta, Alokmay, E-mail: kaustabhdan@gmail.com

2014-04-24

Differential Scanning Calorimetry (DSC) studies on phase transitions of the pure liquid crystalline material N-4-methoxybenzylidene-4-butylaniline (MBBA) and mixtures of MBBA and the amphiphile Stearic Acid (StA) show significant changes in the behavior of mixture from pure MBBA, as regards the nematic-isotropic (N-I) transition temperature (T{sub c}) and other thermodynamic parameters like enthalpy, specific heat and activation energy with concentration of StA. In particular, the convexity of the Arrhenius plot in pure MBBA vanishes with StA concentration pointing to the formation of a new, perhaps 'nematic-like', phase in the mixtures.

Study on the hydration and microstructure of Portland cement containing diethanol-isopropanolamine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Suhua, E-mail: yc982@163.com; Li, Weifeng; Zhang, Shenbiao

2015-01-15

Diethanol-isopropanolamine (DEIPA) is a tertiary alkanolamine used in the formulation of cement grinding-aid additives and concrete early-strength agents. In this research, isothermal calorimetry was used to study the hydration kinetics of Portland cement with DEIPA. A combination of X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC)–thermogravimetric (TG) analysis and micro-Raman spectroscopy was used to investigate the phase development in the process of hydration. Mercury intrusion porosimetry was used to study the pore size distribution and porosity. The results indicate that DEIPA promotes the formation of ettringite (AFt) and enhances the second hydration rate of the aluminatemore » and ferrite phases, the transformation of AFt into monosulfoaluminate (AFm) and the formation of microcrystalline portlandite (CH) at early stages. At later stages, DEIPA accelerates the hydration of alite and reduces the pore size and porosity.« less

Enhancement of solubility and antidiabetic effects of Repaglinide using spray drying technique in STZ-induced diabetic rats.

PubMed

Varshosaz, Jaleh; Minayian, Mohsen; Ahmadi, Mahdieh; Ghassami, Erfaneh

2017-09-01

The purpose of the study was to enhance the solubility of the poorly water-soluble drug, Repaglinide using spray drying based solid dispersion technique by different carriers including Eudragit E100, hydroxyl propyl cellulose Mw 80 000 and poly vinyl pyrollidone K30. Optimization of the best formulation was carried out according to drug solubility, release profile, particle size and angle of repose of the solid dispersions. The optimized sample was characterized using X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The morphology of the dispersions was studied by SEM. The blood glucose lowering effect of spray dried solid dispersions was studied in normal and streptozocin-induced diabetic rats. The results showed that Eudragit E100 in 1:3 ratio could enhance drug solubility by 100-fold. DSC studies indicated a marked change in melting point of the drug possibly due to strong hydrogen bonds between the drug and Eudragit, while FT-IR study did not show obvious interactions between them. According to XRPD results Repaglinide converted to an amorphous state in the spray dried dispersions. Spray dried Repaglinide reduced the blood glucose level significantly during the 8 h of obtaining blood samples in comparison with untreated drug (p < 0.05).

Interaction of vasicine with calf thymus DNA: Molecular docking, spectroscopic and differential scanning calorimetric insights

NASA Astrophysics Data System (ADS)

R. S., Sai Murali; R. S., Sai Siddhardha; Rajesh Babu, D.; Venketesh, S.; Basavaraju, R.; Nageswara Rao, G.

2017-06-01

The present study brings out the interaction between vasicine, an alkaloid and Adhatoda vasica Nees with double stranded DNA. The physico-chemical interaction between small molecules and nucleic acids is a major area of focus in screening drugs against various cancers. Molecular probing in our study using Molecular Operating Environment (MOE) has revealed interaction of vasicine with DNA double helix. Here we report the interaction of vasicine with Calf thymus DNA. We present for the first time the results obtained from UV-visible, fluorescence spectroscopic and differential scanning calorimetric techniques that suggest a moderate to strong electrostatic, hydrophobic and van der Waals interactions mediating the DNA binding properties of vasicine, leading to disruption of DNA secondary structure.

Amphiphilic naproxen prodrugs: differential scanning calorimetry study on their interaction with phospholipid bilayers.

PubMed

Giuffrida, Maria Chiara; Pignatello, Rosario; Castelli, Francesco; Sarpietro, Maria Grazia

2017-09-01

Naproxen, a nonsteroid anti-inflammatory drug studied for Alzheimer's disease, was conjugated with lipoamino acids (LAA) directly or through a diethylamine (EDA) spacer to improve the drug lipophilicity and the interaction with phospholipid bilayers. The interaction of naproxen and its prodrugs with biomembrane models consisting of dimyristoylphosphatidylcholine multilamellar vesicles was studied by differential scanning calorimetry. The transfer of prodrugs from a lipophilic carrier to a biomembrane model was also studied. Naproxen conjugation to lipoamino acids improves its interaction with biomembrane models and affects the transfer from a lipophilic carrier to biomembrane model. LAA portion may localize between the phospholipid chains; the entity of the interaction depends not only on the presence of the spacer but also on the LAA chain length. Variation of LAA portion can modulate the naproxen prodrugs affinity towards the biological membrane as well as towards the lipophilic carrier. © 2017 Royal Pharmaceutical Society.

Improvement of physicomechanical properties of carbamazepine by recrystallization at different pH values.

PubMed

Javadzadeh, Yousef; Mohammadi, Ameneh; Khoei, Nazaninossadat Seyed; Nokhodchi, Ali

2009-06-01

The morphology of crystals has an appreciable impact role on the physicochemical properties of drugs. Drug properties such as flowability, dissolution, hardness and bioavailability may be affected by crystallinity behaviours of drugs. The objective of this study was to achieve an improved physicomechanical property of carbamazepine powder through recrystallization from aqueous solutions at different pH values. For this purpose, carbamazapine was recrystallized from aqueous solutions at different pH values (1, 7, 11). The morphology of crystals was investigated using scanning electron microscopy; X-ray powder diffraction (XRPD) was used to identify polymorphism; thermodynamic properties were analyzed using differential scanning calorimetery (DSC). Dissolution rate was determined using USP dissolution apparatus. Mechanical behavior of recrystallized carbamazepine powders was investigated by making tablets under different compaction pressure and measuring their hardness. SEM studies showed that the carbamazepine crystallization in different media affected the morphology and size of carbamazepine crystals. The shape of carbamazepine crystals changed from flaky or thin plate-like to needle shape. XRPD and DSC results ruled out any crystallinity changes occurring due to the temperature during recrystallization procedure or pH of crystallization media. The crushing strength of tablets indicated that all of the recrystallized carbamazepine samples had better compactiblity than the original carbamazepine powder. In vitro dissolution studies of carbamazepine samples showed a higher dissolution rate for carbamazepine crystals obtained from media with pH 11 and 1. Carbamazepine particles recrystallized from aqueous solutions of different pH values (all media) appeared to have superior mechanical properties to those of the original carbamazepine sample.

Physicochemical properties of film-coated melt-extruded pellets.

PubMed

Young, Chistopher R; Crowley, Michael; Dietzsch, Caroline; McGinity, James W

2007-02-01

The purpose of this study was to investigate the physicochemical properties of poly(ethylene oxide) (PEO) and guaifenesin containing beads prepared by a melt-extrusion process and film-coated with a methacrylic acid copolymer. Solubility parameter calculations, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), modulated differential scanning calorimetry (MDSC), X-ray powder diffraction (XRPD) and high performance liquid chromatography (HPLC) were used to determine drug/polymer miscibility and/or the thermal processibility of the systems. Powder blends of guaifenesin, PEO and functional excipients were processed using a melt-extrusion and spheronization technique and then film-coated in a fluidized bed apparatus. Solubility parameter calculations were used to predict miscibility between PEO and guaifenesin, and miscibility was confirmed by SEM and observation of a single melting point for extruded drug/polymer blends during MDSC investigations. The drug was stable following melt-extrusion as determined by TGA and HPLC; however, drug release rate from pellets decreased upon storage in sealed HDPE containers with silica desiccants at 40 degrees C/75% RH. The weight loss on drying, porosity and tortuosity determinations were not influenced by storage. Recrystallization of guaifenesin and PEO was confirmed by SEM and XRPD. Additionally, the pellets exhibited a change in adhesion behaviour during dissolution testing. The addition of ethylcellulose to the extruded powder blend decreased and stabilized the drug release rate from the thermally processed pellets. The current study also demonstrated film-coating to be an efficient process for providing melt-extruded beads with pH-dependent drug release properties that were stable upon storage at accelerated conditions.

Neck and whole-body scanning with 5-mCi dose of (123)I as diagnostic tracer in patients with well-differentiated thyroid cancer.

PubMed

Gulzar, Z; Jana, S; Young, I; Bukberg, P; Yen, V; Naddaf, S; Abdel-Dayem, H M

2001-01-01

To determine whether a 5-mCi dose of 123I can be used as an effective radiotracer for assessing the presence of remnant thyroid tissue and for searching for metastatic lesions in patients with well-differentiated thyroid cancer as well as to attempt to ascertain whether a scan performed only at 4 hours is sufficient for accurate diagnosis and might replace the conventional protocol of scanning at both 4 hours and 24 hours. We prospectively studied 27 patients who had undergone near-total thyroidectomy and had a documented diagnosis of well-differentiated thyroid carcinoma. Patients underwent scanning after receiving a 5-mCi dose of 123I, at a time when they had discontinued thyroid replacement therapy and had a thyrotropin level in excess of 30 mIU/mL. Whole-body images at 4 hours and 24 hours were obtained and were compared with posttherapy scans obtained 5 to 7 days after administration of 131I. Scans were interpreted by two board-certified nuclear medicine physicians. Of the 27 patients, 2 (7.4%) showed discordance between the 123I scan performed at 24 hours and the posttherapy 131I scan. When 4-hour images after administration of 123I were compared with the posttherapy 131I scans, a discordance rate of 14.8% (4 of 27 patients) was noted. In addition, two of these four patients showed lesions on the 24-hour images that were not seen on the 4-hour images (one with new lung metastatic involvement and the other with a local recurrence in the lower neck area). The prognosis and treatment of these two patients were substantially changed by the result of the 24-hour images. On comparison of scans obtained after administration of a 5-mCi dose of 123I with those obtained after 131I therapy, we conclude that 5 mCi of 123I produces images that have excellent quality and resolution and also compare favorably with those obtained after 131I therapy. Furthermore, a decrease in the dose of 123I from 10 mCi to 5 mCi lowered the cost of the study without compromising the

Probing hydrogen bond networks in half-sandwich Ru(II) building blocks by a combined 1H DQ CRAMPS solid-state NMR, XRPD, and DFT approach.

PubMed

Chierotti, Michele R; Gobetto, Roberto; Nervi, Carlo; Bacchi, Alessia; Pelagatti, Paolo; Colombo, Valentina; Sironi, Angelo

2014-01-06

The hydrogen bond network of three polymorphs (1α, 1β, and 1γ) and one solvate form (1·H2O) arising from the hydration-dehydration process of the Ru(II) complex [(p-cymene)Ru(κN-INA)Cl2] (where INA is isonicotinic acid), has been ascertained by means of one-dimensional (1D) and two-dimensional (2D) double quantum (1)H CRAMPS (Combined Rotation and Multiple Pulses Sequences) and (13)C CPMAS solid-state NMR experiments. The resolution improvement provided by homonuclear decoupling pulse sequences, with respect to fast MAS experiments, has been highlighted. The solid-state structure of 1γ has been fully characterized by combining X-ray powder diffraction (XRPD), solid-state NMR, and periodic plane-wave first-principles calculations. None of the forms show the expected supramolecular cyclic dimerization of the carboxylic functions of INA, because of the presence of Cl atoms as strong hydrogen bond (HB) acceptors. The hydration-dehydration process of the complex has been discussed in terms of structure and HB rearrangements.

Wide scanning spherical antenna

NASA Technical Reports Server (NTRS)

Shen, Bing (Inventor); Stutzman, Warren L. (Inventor)

1995-01-01

A novel method for calculating the surface shapes for subreflectors in a suboptic assembly of a tri-reflector spherical antenna system is introduced, modeled from a generalization of Galindo-Israel's method of solving partial differential equations to correct for spherical aberration and provide uniform feed to aperture mapping. In a first embodiment, the suboptic assembly moves as a single unit to achieve scan while the main reflector remains stationary. A feed horn is tilted during scan to maintain the illuminated area on the main spherical reflector fixed throughout the scan thereby eliminating the need to oversize the main spherical reflector. In an alternate embodiment, both the main spherical reflector and the suboptic assembly are fixed. A flat mirror is used to create a virtual image of the suboptic assembly. Scan is achieved by rotating the mirror about the spherical center of the main reflector. The feed horn is tilted during scan to maintain the illuminated area on the main spherical reflector fixed throughout the scan.

Using differential scanning calorimetry, laser refractometry, electrical conductivity and spectrophotometry for discrimination of different types of Bulgarian honey

NASA Astrophysics Data System (ADS)

Vlaeva, I.; Nikolova, K.; Bodurov, I.; Marudova, M.; Tsankova, D.; Lekova, S.; Viraneva, A.; Yovcheva, T.

2017-01-01

The potential of several physical methods for investigation of the botanical origin of honey has been discussed. Samples from the three most prevalent types of honey in Bulgaria (acacia, linden and honeydew) have been used. They have been examined by laser refractometry, UV, VIS and FTIR spectroscopy, electric conductivity measurement and differential scanning calorimetry. The purpose of this study was to reveal the physical characterizations of honeys from different flora produced in Bulgaria and to identify honeys with a high apitherapy potential for future studies.

Study of the recrystallization in coated pellets - effect of coating on API crystallinity.

PubMed

Nikowitz, Krisztina; Pintye-Hódi, Klára; Regdon, Géza

2013-02-14

Coated diltiazem hydrochloride-containing pellets were prepared using the solution layering technique. Unusual thermal behavior was detected with differential scanning calorimetry (DSC) and its source was determined using thermogravimetry (TG), X-ray powder diffraction (XRPD) and hot-stage microscopy. The coated pellets contained diltiazem hydrochloride both in crystalline and amorphous form. Crystallization occurs on heat treatment causing an exothermic peak on the DSC curves that only appears in pellets containing both diltiazem hydrochloride and the coating. Results indicate that the amorphous fraction is situated in the coating layer. The migration of drugs into the coating layer can cause changes in its degree of crystallinity. Polymeric coating materials should therefore be investigated as possible crystallization inhibitors. Copyright © 2012 Elsevier B.V. All rights reserved.

Differential phase contrast with a segmented detector in a scanning X-ray microprobe

PubMed Central

Hornberger, B.; de Jonge, M. D.; Feser, M.; Holl, P.; Holzner, C.; Jacobsen, C.; Legnini, D.; Paterson, D.; Rehak, P.; Strüder, L.; Vogt, S.

2008-01-01

Scanning X-ray microprobes are unique tools for the nanoscale investigation of specimens from the life, environmental, materials and other fields of sciences. Typically they utilize absorption and fluorescence as contrast mechanisms. Phase contrast is a complementary technique that can provide strong contrast with reduced radiation dose for weakly absorbing structures in the multi-keV range. In this paper the development of a segmented charge-integrating silicon detector which provides simultaneous absorption and differential phase contrast is reported. The detector can be used together with a fluorescence detector for the simultaneous acquisition of transmission and fluorescence data. It can be used over a wide range of photon energies, photon rates and exposure times at third-generation synchrotron radiation sources, and is currently operating at two beamlines at the Advanced Photon Source. Images obtained at around 2 keV and 10 keV demonstrate the superiority of phase contrast over absorption for specimens composed of light elements. PMID:18552427

Characterization of Thermal Behavior of Epoxy Composites Reinforced with Curaua Fibers by Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Barcelos, Mariana A.; Ribeiro, Carolina Gomes D.; Ferreira, Jordana; Vieira, Janaina da S.; Margem, Frederico M.; Monteiro, Sergio N.

Epoxy composites reinforced with natural lignocellulosic fibers have, in recent times, been gaining attention in engineering areas as lighter and cheaper alternatives for traditional composites such as the "fiberglass". The curaua fiber is the one strongest today being considered as reinforcement of composites for automobile interior parts. In fact, several studies are currently being dedicated to curaua fiber composites since physical and mechanical properties are required for practical uses. In this work, the thermal behavior of epoxy composites reinforced with up to 30 % in volume of curaua fibers was investigated by differential scanning calorimetry, DSC. The results showed endothermic and exothermic events associated with water release and possible molecular chain amorphous transformation. Comparison with similar composites permitted to propose mechanism that explains this DSC thermal behavior.

Interaction of vasicine with calf thymus DNA: Molecular docking, spectroscopic and differential scanning calorimetric insights.

PubMed

R S, Sai Murali; R S, Sai Siddhardha; D, Rajesh Babu; S, Venketesh; R, Basavaraju; G, Nageswara Rao

2017-06-05

The present study brings out the interaction between vasicine, an alkaloid and Adhatoda vasica Nees with double stranded DNA. The physico-chemical interaction between small molecules and nucleic acids is a major area of focus in screening drugs against various cancers. Molecular probing in our study using Molecular Operating Environment (MOE) has revealed interaction of vasicine with DNA double helix. Here we report the interaction of vasicine with Calf thymus DNA. We present for the first time the results obtained from UV-visible, fluorescence spectroscopic and differential scanning calorimetric techniques that suggest a moderate to strong electrostatic, hydrophobic and van der Waals interactions mediating the DNA binding properties of vasicine, leading to disruption of DNA secondary structure. Copyright © 2017 Elsevier B.V. All rights reserved.

Stability of some Cactaceae proteins based on fluorescence, circular dichroism, and differential scanning calorimetry measurements.

PubMed

Gorinstein, S; Zemser, M; Vargas-Albores, F; Ochoa, J L; Paredes-Lopez, O; Scheler, C; Aksu, S; Salnikow, J

1999-02-01

Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of alpha-helix.

Evaluation of Thermal Stability of Ausferrite in Austempered Ductile Iron Using Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Warsinski, Karl C.

Austempered Ductile Iron (ADI) is prone to changes in microstructure and mechanical properties when exposed to elevated service temperatures. Differential Scanning Calorimetry has been used to evaluate the stabilizing effects of copper, nickel, molybdenum, and cobalt on the ausferrite structure. Previous studies have conflated the effects of various alloy additions, and little effort has been made to systematically catalog the effects of individual elements. The focus of the current research has been to identify alloying elements that more strongly stabilize the ausferrite structure in order to improve service life of ADI at elevated temperatures. Nickel has been shown to have a moderate stabilizing effect, while copper and molybdenum cause a much sharper increase in activation energy. Cobalt has a high stabilizing effect at 0.5% addition by weight, but a further increase to 2.36% results in a slight decrease in activation energy.

Differential phase acoustic microscope for micro-NDE

NASA Technical Reports Server (NTRS)

Waters, David D.; Pusateri, T. L.; Huang, S. R.

1992-01-01

A differential phase scanning acoustic microscope (DP-SAM) was developed, fabricated, and tested in this project. This includes the acoustic lens and transducers, driving and receiving electronics, scanning stage, scanning software, and display software. This DP-SAM can produce mechanically raster-scanned acoustic microscopic images of differential phase, differential amplitude, or amplitude of the time gated returned echoes of the samples. The differential phase and differential amplitude images provide better image contrast over the conventional amplitude images. A specially designed miniature dual beam lens was used to form two foci to obtain the differential phase and amplitude information of the echoes. High image resolution (1 micron) was achieved by applying high frequency (around 1 GHz) acoustic signals to the samples and placing two foci close to each other (1 micron). Tone burst was used in this system to obtain a good estimation of the phase differences between echoes from the two adjacent foci. The system can also be used to extract the V(z) acoustic signature. Since two acoustic beams and four receiving modes are available, there are 12 possible combinations to produce an image or a V(z) scan. This provides a unique feature of this system that none of the existing acoustic microscopic systems can provide for the micro-nondestructive evaluation applications. The entire system, including the lens, electronics, and scanning control software, has made a competitive industrial product for nondestructive material inspection and evaluation and has attracted interest from existing acoustic microscope manufacturers.

Step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS): a spectral deconvolution method for weak absorber detection in the presence of strongly overlapping background absorptions.

PubMed

Liu, Lixian; Mandelis, Andreas; Huan, Huiting; Michaelian, Kirk H

2017-04-01

The determination of small absorption coefficients of trace gases in the atmosphere constitutes a challenge for analytical air contaminant measurements, especially in the presence of strongly absorbing backgrounds. A step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS) method was developed to suppress the coherent external noise and spurious photoacoustic (PA) signals caused by strongly absorbing backgrounds. The infrared absorption spectra of acetylene (C₂H₂) and local air were used to verify the performance of the step-scan DFTIR-PAS method. A linear amplitude response to C₂H₂ concentrations from 100 to 5000 ppmv was observed, leading to a theoretical detection limit of 5 ppmv. The differential mode was capable of eliminating the coherent noise and dominant background gas signals, thereby revealing the presence of the otherwise hidden C₂H₂ weak absorption. Thus, the step-scan DFTIR-PAS modality was demonstrated to be an effective approach for monitoring weakly absorbing gases with absorption bands overlapped by strongly absorbing background species.

Theoretical analysis of Lumry-Eyring models in differential scanning calorimetry

PubMed Central

Sanchez-Ruiz, Jose M.

1992-01-01

A theoretical analysis of several protein denaturation models (Lumry-Eyring models) that include a rate-limited step leading to an irreversibly denatured state of the protein (the final state) has been carried out. The differential scanning calorimetry transitions predicted for these models can be broadly classified into four groups: situations A, B, C, and C′. (A) The transition is calorimetrically irreversible but the rate-limited, irreversible step takes place with significant rate only at temperatures slightly above those corresponding to the transition. Equilibrium thermodynamics analysis is permissible. (B) The transition is distorted by the occurrence of the rate-limited step; nevertheless, it contains thermodynamic information about the reversible unfolding of the protein, which could be obtained upon the appropriate data treatment. (C) The heat absorption is entirely determined by the kinetics of formation of the final state and no thermodynamic information can be extracted from the calorimetric transition; the rate-determining step is the irreversible process itself. (C′) same as C, but, in this case, the rate-determining step is a previous step in the unfolding pathway. It is shown that ligand and protein concentration effects on transitions corresponding to situation C (strongly rate-limited transitions) are similar to those predicted by equilibrium thermodynamics for simple reversible unfolding models. It has been widely held in recent literature that experimentally observed ligand and protein concentration effects support the applicability of equilibrium thermodynamics to irreversible protein denaturation. The theoretical analysis reported here disfavors this claim. PMID:19431826

Native denaturation differential scanning fluorimetry: Determining the effect of urea using a quantitative real-time thermocycler.

PubMed

Childers, Christine L; Green, Stuart R; Dawson, Neal J; Storey, Kenneth B

2016-09-01

The effect of protein stability on kinetic function is monitored with many techniques that often require large amounts of expensive substrates and specialized equipment not universally available. We present differential scanning fluorimetry (DSF), a simple high-throughput assay performed in real-time thermocyclers, as a technique for analysis of protein unfolding. Furthermore, we demonstrate a correlation between the half-maximal rate of protein unfolding (Knd), and protein unfolding by urea (I50). This demonstrates that DSF methods can determine the structural stability of an enzyme's active site and can compare the relative structural stability of homologous enzymes with a high degree of sequence similarity. Copyright © 2016 Elsevier Inc. All rights reserved.

The use of differential scanning calorimetry for the evaluation of dental materials. I. Cements, cavity lining materials and anterior restorative materials.

PubMed

McCabe, J F; Wilson, H J

1980-03-01

Thermal changes occurring during the setting of restorative materials have been measured accurately using a differential scanning calorimeter. The results were used to evaluate setting characteristics. The heat of reaction and rate of heat output may be significant in determining thermal damage to the pulp. The heat capacity is related to thermal insulation properties. These properties have been determined and their effect on the efficacy of restorative materials discussed.

Selective removal of monoterpenes from bergamot oil by inclusion in deoxycholic acid.

PubMed

Fantin, Giancarlo; Fogagnolo, Marco; Maietti, Silvia; Rossetti, Stefano

2010-05-12

A new approach for removing monoterpenes (MTs) from bergamot oil by selective inclusion in deoxycholic acid (DCA) is proposed. The inclusion process is very efficient, the included fraction being composed mainly of limonene (71.7%) and gamma-terpinene (19.8%). On the other hand, the deterpenated bergamot oil fraction showed for the linalool and linalyl acetate derivatives significant increases from 16.6 and 21.4% to 18.3 and 42.2%, respectively. The major advantages of this methodology are its simplicity, the mild conditions employed, and the quantitative recovery of both host (DCA) and guest (monoterpenes) compounds. Differential scanning calorimetry (DSC), thermal gravimetry (TG), powder X-ray diffractometry (XRPD), infrared spectroscopy (IR), and proton magnetic resonance ((1)H NMR) analysis were used to investigate and characterize the inclusion compounds.

Application of differential scanning calorimetry to measure the differential binding of ions, water and protons in the unfolding of DNA molecules.

PubMed

Olsen, Chris M; Shikiya, Ronald; Ganugula, Rajkumar; Reiling-Steffensmeier, Calliste; Khutsishvili, Irine; Johnson, Sarah E; Marky, Luis A

2016-05-01

The overall stability of DNA molecules globally depends on base-pair stacking, base-pairing, polyelectrolyte effect and hydration contributions. In order to understand how they carry out their biological roles, it is essential to have a complete physical description of how the folding of nucleic acids takes place, including their ion and water binding. To investigate the role of ions, water and protons in the stability and melting behavior of DNA structures, we report here an experimental approach i.e., mainly differential scanning calorimetry (DSC), to determine linking numbers: the differential binding of ions (Δnion), water (ΔnW) and protons (ΔnH(+)) in the helix-coil transition of DNA molecules. We use DSC and temperature-dependent UV spectroscopic techniques to measure the differential binding of ions, water, and protons for the unfolding of a variety of DNA molecules: salmon testes DNA (ST-DNA), one dodecamer, one undecamer and one decamer duplexes, nine hairpin loops, and two triplexes. These methods can be applied to any conformational transition of a biomolecule. We determined complete thermodynamic profiles, including all three linking numbers, for the unfolding of each molecule. The favorable folding of a DNA helix results from a favorable enthalpy-unfavorable entropy compensation. DSC thermograms and UV melts as a function of salt, osmolyte and proton concentrations yielded releases of ions and water. Therefore, the favorable folding of each DNA molecule results from the formation of base-pair stacks and uptake of both counterions and water molecules. In addition, the triplex with C(+)GC base triplets yielded an uptake of protons. Furthermore, the folding of a DNA duplex is accompanied by a lower uptake of ions and a similar uptake of four water molecules as the DNA helix gets shorter. In addition, the oligomer duplexes and hairpin thermodynamic data suggest ion and water binding depends on the DNA sequence rather than DNA composition. Copyright �

Hydrogen bonding Part 53. Correlation of differential scanning calorimetric data with IR and dissociation vapor pressure studies of transitions of hexamethonium chloride and bromide dihydrates and hexamethonium bromide monohydrate

NASA Astrophysics Data System (ADS)

Snider, Barbara L.; Harmon, Kenneth M.

1994-03-01

Differential scanning calorimetry of hexamethonium chloride dihydrate shows an endothermic transition of 2.70 kcal mol -1 at 36.81°C. This correlates well with the temperatures observed by IR spectra (36°C) and equilibrium dissociation vapor pressure studies (37°C) for the transition between Type I planar cluster and Type II extended linear HOH⋯Cl - hydrogen bonding, and with the value of 2.77 kcal mol -1 for this transition derived by Hess' law treatment of dissociation vapor pressure data. Differential scanning calorimetry of hexamethonium bromide shows a rapid endothermic transition of 2.38 kcal mol -1 at 35.15°C and a very slow endothermic transition of about 12-13 kcal mol -1 centered near 50°C. This latter endotherm corresponds to the transition between Type I and Type II HOH⋯Br - hydrogen bonding observed by IR and vapor pressure studies at 49°C. The nature of the 35.15°C endotherm is not known. Hexamethonium bromide also shows a third endotherm at 142.91°C, which presumably results from melting of hydrate in the sealed DSC cell. Combined analysis of differential scanning calorimetry and dissociation vapor pressure data predicts a value of about -13 kcal mol -1 for an exothermic disproportionation at 52°C of two hexamethonium bromide monohydrate to Type II dihydrate and anhydrous bromide.

Visual scanning with or without spatial uncertainty and time-sharing performance

NASA Technical Reports Server (NTRS)

Liu, Yili; Wickens, Christopher D.

1989-01-01

An experiment is reported that examines the pattern of task interference between visual scanning as a sequential and selective attention process and other concurrent spatial or verbal processing tasks. A distinction is proposed between visual scanning with or without spatial uncertainty regarding the possible differential effects of these two types of scanning on interference with other concurrent processes. The experiment required the subject to perform a simulated primary tracking task, which was time-shared with a secondary spatial or verbal decision task. The relevant information that was needed to perform the decision tasks were displayed with or without spatial uncertainty. The experiment employed a 2 x 2 x 2 design with types of scanning (with or without spatial uncertainty), expected scanning distance (low/high), and codes of concurrent processing (spatial/verbal) as the three experimental factors. The results provide strong evidence that visual scanning as a spatial exploratory activity produces greater task interference with concurrent spatial tasks than with concurrent verbal tasks. Furthermore, spatial uncertainty in visual scanning is identified to be the crucial factor in producing this differential effect.

A Differential Scanning Calorimetry Method for Construction of Continuous Cooling Transformation Diagram of Blast Furnace Slag

NASA Astrophysics Data System (ADS)

Gan, Lei; Zhang, Chunxia; Shangguan, Fangqin; Li, Xiuping

2012-06-01

The continuous cooling crystallization of a blast furnace slag was studied by the application of the differential scanning calorimetry (DSC) method. A kinetic model describing the correlation between the evolution of the degree of crystallization with time was obtained. Bulk cooling experiments of the molten slag coupled with numerical simulation of heat transfer were conducted to validate the results of the DSC methods. The degrees of crystallization of the samples from the bulk cooling experiments were estimated by means of the X-ray diffraction (XRD) and the DSC method. It was found that the results from the DSC cooling and bulk cooling experiments are in good agreement. The continuous cooling transformation (CCT) diagram of the blast furnace slag was constructed according to crystallization kinetic model and experimental data. The obtained CCT diagram characterizes with two crystallization noses at different temperature ranges.

Differential scanning calorimetric study of the binding between native DNA and its primary water of hydration.

NASA Astrophysics Data System (ADS)

Marlowe, R. L.; Lukan, A. M.; Lee, S. A.; Anthony, L.; Rupprecht, A.

1996-03-01

Differential scanning calorimetry was used to measure the binding strength between calf-thymus DNA and its primary water of hydration. The specific heat of wet-spun films was found to have a broad endothermic transition near 80 ^oC and a sharp exothermic transition near 250 ^oC. The broad transition is believed to be mainly due to the breaking of the bonds of the strongly bound water of hydration. This transition was found to be reversible, as expected. Kissinger analysis indicates that the activation barrier for breaking the bonds of these water molecules is about 0.6 eV. The sharp transition appeared to be an indication of a thermal decomposition of the DNA. Samples taken above this transition lost mass, showed evidence of having melted, and had turned black in color. This transition is irreversible.

Rapid detection of biofilms and adherent pathogens using scanning confocal laser microscopy and episcopic differential interference contrast microscopy.

PubMed

Keevil, C W

2003-01-01

Knowledge of biofilm structure and function has changed significantly in the last few years due to advances in light microscopy. One pertinent example is the use of scanning confocal laser microscopy (SCLM) to visualise corrosion pits caused by the biofilm mosaic footprint on corroding metal surfaces. Nevertheless, SCLM has some limitations as to its widespread use, including cost, inability to observe motile bacteria and eukaryotic grazers within biofilms, and difficulty to scan a curved surface. By contrast, episcopic differential interference contrast (EDIC) microscopy has provided a rapid, real time analysis of biofilms on opaque, curved, natural or man-made surfaces without the need for cover slips and oil. EDIC, coupled with epi-fluorescence (EDIC/EF), microscopy has been used successfully to visualise the 3-D biofilm structure, physiological niches, protozoal grazing and iron biomineralization, and the location of specific pathogens such as Legionella pneumophila, Campylobacter jejuni and Cryptosporidium parvum. These species were identified using gold nanoparticles or fluorophores coupled to monoclonal antibodies or 16S rRNA probes, respectively. Among its many potential uses, the EDIC technique will provide a rapid procedure to facilitate the calibration of the modern generation of biofilm-sensing electrodes.

Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

PubMed

Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

2012-04-12

Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

Ciprofloxacin HCl-loaded calcium carbonate nanoparticles: preparation, solid state characterization, and evaluation of antimicrobial effect against Staphylococcus aureus.

PubMed

Maleki Dizaj, Solmaz; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad-Hossein; Adibkia, Khosro

2017-05-01

Ciprofloxacin HCl-loaded calcium carbonate (CaCO 3 ) nanoparticles were prepared via a w/o microemulsion method and characterized by dynamic light scattering, scanning electron microscopy, X-ray powder diffraction (XRPD) analysis, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The in vitro drug release profiles as well as antimicrobial effect against Staphylococcus aureus (S. aureus) were also evaluated. The antibacterial effect was studied using serial dilution technique to determine the minimum inhibitory concentration (MIC) of the nanoparticles and was confirmed by streak cultures. The mean particle size, drug loading and entrapment efficiency were calculated to be 116.09 nm, 20.49% and 44.05%, respectively. PXRD and FTIR studies confirmed that both vaterite and calcite polymorphs of CaCO 3 were formed during the preparation process. In vitro release profiles of the nanoparticles showed slow release pattern for 12 h. The drug-loaded nanoparticles showed similar MICs against S. aureus compared to untreated drug. However, a preserved antimicrobial effect was observed for drug-loaded nanoparticles compared to untreated drug after 2 days of incubation.

Antisolvent precipitation technique: A very promising approach to crystallize curcumin in presence of polyvinyl pyrrolidon for solubility and dissolution enhancement.

PubMed

Sadeghi, Fatemeh; Ashofteh, Mohammad; Homayouni, Alireza; Abbaspour, Mohammadreza; Nokhodchi, Ali; Garekani, Hadi Afrasiabi

2016-11-01

Curcumin with a vast number of pharmacological activities is a poorly water soluble drug which its oral bioavailability is profoundly limited by its dissolution or solubility in GI tract. Curcumin could be a good anticancer drug if its solubility could be increased. Therefore, the aim of the present study was to increase the dissolution rate of curcumin by employing antisolvent crystallization technique and to investigate the effect of polyvinyl pyrrolidone K30 (PVP) as colloidal particles in crystallization medium on resultant particles. Curcumin was crystalized in the presence of different amounts of PVP by antisolvent crystallization method and their physical mixtures were prepared for comparison purposes. The samples were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR). The solubility and dissolution of the treated and untreated curcumin were also determined. Antisolvent crystallization of curcumin led to the formation of particles with no definite geometric shape. It was interesting to note that the DSC and XRPD studies indicated the formation of a new polymorph and less crystallinity for particles crystallized in the absence of PVP. However, the crystallized curcumin in the presence of PVP was completely amorphous. All crystalized curcumin samples showed much higher dissolution rate compared to untreated curcumin. The amount of curcumin dissolved within 10 for treated curcumin in the presence of PVP (1:1 curcumin:PVP) was 7 times higher than untreated curcumin and this enhancement in the dissolution for curcumin samples crystallized in the absence of PVP was around 5 times. Overall' the results of this study showed that antisolvent crystallization method in the absence or presence of small amounts of PVP is very efficient in increasing the dissolution rate of curcumin to achieve better efficiency for curcumin. Copyright © 2016

Novel inclusion complex of ibuprofen tromethamine with cyclodextrins: physico-chemical characterization.

PubMed

Al Omari, Mahmoud M; Daraghmeh, Nidal H; El-Barghouthi, Musa I; Zughul, Mohammad B; Chowdhry, Babur Z; Leharne, Stephen A; Badwan, Adnan A

2009-10-15

Guest-host interactions of ibuprofen tromethamine salt (Ibu.T) with native and modified cyclodextrins (CyDs) have been investigated using several techniques, namely phase solubility diagrams (PSDs), proton nuclear magnetic resonance ((1)H NMR), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffractometry (XRPD), scanning-electron microscopy (SEM) and molecular mechanics (MM). From the analysis of PSD data (A(L)-type) it is concluded that the anionic tromethamine salt of ibuprofen (pK(a)=4.55) forms 1:1 soluble complexes with all CyDs investigated in buffered water at pH 7.0, while the neutral form of Ibu forms an insoluble complex with beta-CyD (B(S)-type) in buffered water at pH 2.0. Ibu.T has a lower tendency to complex with beta-CyD (K(11)=58 M(-1) at pH 7.0) compared with the neutral Ibu (K(11)=4200 M(-1)) in water. Complex formation of Ibu.T with beta-CyD (DeltaG(o)=-20.4 kJ/mol) is enthalpy driven (DeltaH(o)=-22.9 kJ/mol) and is accompanied by a small unfavorable entropy (DeltaS(o)=-8.4 J/mol K) change. (1)H NMR studies and MM computations revealed that, on complexation, the hydrophobic central benzene ring of Ibu.T and part of the isobutyl group reside within the beta-CyD cavity leaving the peripheral groups (carboxylate, tromethamine and methyl groups) located near the hydroxyl group networks at either rim of beta-CyD. PSD, (1)H NMR, DSC, FT-IR, XRPD, SEM and MM studies confirmed the formation of Ibu.T/beta-CyD inclusion complex in solution and the solid state.

Preparation and characterisation of hydrocortisone particles using a supercritical fluids extraction process.

PubMed

Velaga, Sitaram P; Ghaderi, Raouf; Carlfors, Johan

2002-01-14

Crystallisation and subsequent milling of pharmaceutical powders by traditional methods often cause variations in physicochemical properties thereby influencing bioavailability of the formulation. Crystallisation of drug substances using supercritical fluids (SFs) offers some advantages over existing traditional methods in controlling particle characteristics. The novel particle formation method, solution enhanced dispersion by supercritical (SEDS) fluids was used for the preparation of hydrocortisone (HC) particles. The influence of processing conditions on the solid-state properties of the particles was studied. HC, an anti-inflammatory corticosteroid, particles were prepared from acetone and methanol solutions using the SEDS process. The solutions were dispersed with supercritical CO(2), acting as an anti-solvent, through a specially designed co-axial nozzle into a pressured vessel maintained at a specific constant temperature and pressure. The temperatures and pressures studied were 40-90 degrees C and 90-180 bar, respectively. The relative flow rates of drug solution to CO(2) were varied between 0.002 and 0.03. Solid-state characterisation of particles included differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), solubility studies and scanning electron microscopy (SEM) examination. The aerodynamic properties of SEDS prepared particles were determined by a multistage liquid impinger (MLI). Particles produced from acetone solutions were crystalline needles, melting at 221+/-2 degrees C. Their morphology was independent of processing conditions. With methanol solutions, particles were flakes or needles depending on the processing temperature and pressure. This material melted at 216+/-1 degrees C, indicating a different crystal structure from the original material, in agreement with observed differences in the position and intensity of the XRPD peaks. The simulated lung deposition, using the MLI, for HC powder was improved after SEDS

Investigation of nanosized crystalline form to improve the oral bioavailability of poorly water soluble cilostazol.

PubMed

Miao, Xiaoqing; Sun, Changshan; Jiang, Tongying; Zheng, Li; Wang, Tianyi; Wang, Siling

2011-01-01

The aim of this study was to develop cilostazol (CLT) nanocrystals intended to improve its dissolution rate and enhance its bioavailability. In this study, CLT nanosuspension was prepared by the anti-solvent and high-pressure homogenization method. The effects of the production parameters, such as the stabilizer concentration, pressure and number of cycles, were investigated. Characterization of the product was performed by scanning electron microscopy (SEM), Nitrogen adsorption, differential scanning calorimetry (DSC), X-ray powder diffraction analysis (XRPD), X-ray Photoelectron Spectroscopy (XPS), particle size analysis and dissolution testing. Additionally, the comparison studies of oral bioavailability in beagle dogs of three type tables were performed. The images of SEM showed a spherical smooth CLT powder, and Nitrogen adsorption test revealed spray dried powder were porous with high BET surface area compared with that of raw CLT. DSC and XRPD results demonstrated that the combination of preferred polymorph B and C of CLT were prepared successfully, the saturation solubility of the nanosized crystalline powder is about 5 fold greater than that of raw CLT, and the dissolution rate was enhanced 4 fold than that of raw CLT. The Cmax and AUC0-48h of CLT nanosized crystalline tablets were 2.1 fold and 1.9 fold, and 3.0 fold and 2.3 fold compared with those of the nanosized tablets and commercial tablets, respectively. The anti-solvent-high-pressure homogenization technique was employed successfully to produce cilostazol nanosuspensions. The bioavailability of CLT tablets prepared using spray dried nanosized crystalline powder after oral administration to dogs was markedly increased compared with that produced by nanosized tablets and commercial tablets, because of its greater dissolution rate owing to its transition of the crystalline state to form C and form B, reduced particle size and porous structure with increased surface area.

Deconvolution of complex differential scanning calorimetry profiles for protein transitions under kinetic control.

PubMed

Toledo-Núñez, Citlali; Vera-Robles, L Iraís; Arroyo-Maya, Izlia J; Hernández-Arana, Andrés

2016-09-15

A frequent outcome in differential scanning calorimetry (DSC) experiments carried out with large proteins is the irreversibility of the observed endothermic effects. In these cases, DSC profiles are analyzed according to methods developed for temperature-induced denaturation transitions occurring under kinetic control. In the one-step irreversible model (native → denatured) the characteristics of the observed single-peaked endotherm depend on the denaturation enthalpy and the temperature dependence of the reaction rate constant, k. Several procedures have been devised to obtain the parameters that determine the variation of k with temperature. Here, we have elaborated on one of these procedures in order to analyze more complex DSC profiles. Synthetic data for a heat capacity curve were generated according to a model with two sequential reactions; the temperature dependence of each of the two rate constants involved was determined, according to the Eyring's equation, by two fixed parameters. It was then shown that our deconvolution procedure, by making use of heat capacity data alone, permits to extract the parameter values that were initially used. Finally, experimental DSC traces showing two and three maxima were analyzed and reproduced with relative success according to two- and four-step sequential models. Copyright © 2016 Elsevier Inc. All rights reserved.

Stability of polymorphic forms of ranitidine hydrochloride.

PubMed

Wu, V; Rades, T; Saville, D J

2000-07-01

Ranitidine-HCl can exist in two different polymorphic forms: form I (m.p. 134-140 degrees C) and form II (m.p. 140-144 degrees C). In the present study the stability of form I of ranitidine-HCl to a selection of powder pretreatments, to reflect conditions which might occur in manufacturing procedures, and also to a limited range of storage conditions was investigated. The original samples of form I and form II used were characterised by X-ray powder diffraction (XRPD), hot stage microscopy (HSM) and differential scanning calorimetry (DSC). A quantitative XRPD method for determining the fraction of form II in the presence of form I was used. XRPD data were analysed using regression techniques and artificial neural networks (ANN). The quantitative XRPD technique was then used to monitor the relative proportion of form II in each treated sample. Pretreatments of form I included (i) mixing with form II or with common excipients (ii) compression and grinding (iii) contact with solvents (followed by drying) before storage. Storage conditions involved three temperatures (20 degrees C, 30 degrees C, 42 degrees C) and three relative humidities (45% RH; 55% RH; 75% RH). Samples were stored for a period of 6 months. A limited factorial design was used. No increase in the form II:form I ratio was observed in the following pretreatment processes: introduction of form II nuclei into form I; introduction of excipients to form I; compression of form I powder at 5 and 15 tons; normal mixing and grinding processes; addition of isopropanol (IPA) or water/IPA mix followed by drying. In the pretreatment process where water was added to form I powder (with most or all of the powder dissolving), drying of the liquefied mass led to a mix of form I and form II. On storage at room temperature (20-30 degrees C), low relative humidity (45-55% RH), and in an air-tight container there was no increase in the form II:form I ratio. Storage of form I/form II mixes, particularly at high humidity

Differential scanning fluorimetry illuminates silk feedstock stability and processability.

PubMed

Dicko, C; Kasoju, N; Hawkins, N; Vollrath, F

2016-01-07

The ability to design and implement silk feedstock formulations for tailored spinning has so far eluded the bioengineers. Recently, the high throughput screening technique of differential scanning fluorimetry (DSF) demonstrated the link between the instability transition temperature (Ti) and the processability of the silk feedstock. Using DSF we screened a large set of chemicals known to affect solvent quality. A multivariate analysis of the results shows that, regardless of the diversity of chemicals, three groupings are significantly distinguishable: G1 = similar to native silk; G2 = largely dominated by electrostatic interactions; and G3 = dominated by chelating interactions. We propose a thermodynamic analysis based on a pre- and post-transition fit to estimate the van't Hoff enthalpies (ΔHv) and the instability temperature (Ti). Our analysis shows that the ΔTi and ΔHv values were distinct: G1 (ΔTi = 0.23 ± 0.2; ΔHv = -159.1 ± 5.6 kcal mol(-1)), G2 (ΔTi = -7.3 ± 0.7; ΔHv = -191.4 ± 5.5 kcal mol(-1)), and G3 (ΔTi = -19.9 ± 3.3; ΔHv = -68.8 ± 6.0 kcal mol(-1)). Our analysis further combined the ΔTi value and the ΔHv value using stability ΔΔG to find that G1 only marginally stabilizes native silks (ΔΔG = -0.15 ± 0.04 kcal mol(-1)), whereas G2 and G3 destabilize native silk (ΔΔG = 3.8 ± 0.11 and ΔΔG = 3.8 ± 0.3 kcal mol(-1), respectively). Here our analysis shows that native silk has a complex multistep transition that is possibly non-cooperative. However, all three groupings also show a direct and cooperative transition with varied stabilization effects. This analysis suggests that native silks are able to sample multiple substates prior to undergoing (or to delay) the final transition. We conclude by hypothesizing that the observed energetic plasticity may be mediated by a fragile packaging of the silk tertiary structure that is readily lost when the solvent quality changes.

Effect of Copper Oxide, Titanium Dioxide, and Lithium Fluoride on the Thermal Behavior and Decomposition Kinetics of Ammonium Nitrate

NASA Astrophysics Data System (ADS)

Vargeese, Anuj A.; Mija, S. J.; Muralidharan, Krishnamurthi

2014-07-01

Ammonium nitrate (AN) is crystallized along with copper oxide, titanium dioxide, and lithium fluoride. Thermal kinetic constants for the decomposition reaction of the samples were calculated by model-free (Friedman's differential and Vyzovkins nonlinear integral) and model-fitting (Coats-Redfern) methods. To determine the decomposition mechanisms, 12 solid-state mechanisms were tested using the Coats-Redfern method. The results of the Coats-Redfern method show that the decomposition mechanism for all samples is the contracting cylinder mechanism. The phase behavior of the obtained samples was evaluated by differential scanning calorimetry (DSC), and structural properties were determined by X-ray powder diffraction (XRPD). The results indicate that copper oxide modifies the phase transition behavior and can catalyze AN decomposition, whereas LiF inhibits AN decomposition, and TiO2 shows no influence on the rate of decomposition. Possible explanations for these results are discussed. Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Energetic Materials to view the free supplemental file.

Identification and quantitation of semi-crystalline microplastics using image analysis and differential scanning calorimetry.

PubMed

Rodríguez Chialanza, Mauricio; Sierra, Ignacio; Pérez Parada, Andrés; Fornaro, Laura

2018-06-01

There are several techniques used to analyze microplastics. These are often based on a combination of visual and spectroscopic techniques. Here we introduce an alternative workflow for identification and mass quantitation through a combination of optical microscopy with image analysis (IA) and differential scanning calorimetry (DSC). We studied four synthetic polymers with environmental concern: low and high density polyethylene (LDPE and HDPE, respectively), polypropylene (PP), and polyethylene terephthalate (PET). Selected experiments were conducted to investigate (i) particle characterization and counting procedures based on image analysis with open-source software, (ii) chemical identification of microplastics based on DSC signal processing, (iii) dependence of particle size on DSC signal, and (iv) quantitation of microplastics mass based on DSC signal. We describe the potential and limitations of these techniques to increase reliability for microplastic analysis. Particle size demonstrated to have particular incidence in the qualitative and quantitative performance of DSC signals. Both, identification (based on characteristic onset temperature) and mass quantitation (based on heat flow) showed to be affected by particle size. As a result, a proper sample treatment which includes sieving of suspended particles is particularly required for this analytical approach.

PET scanning in head and neck oncology: a review.

PubMed

McGuirt, W F; Greven, K; Williams, D; Keyes, J W; Watson, N; Cappellari, J O; Geisinger, K R

1998-05-01

The objective of this study was to review and describe the usage of fluorine-labeled deoxyglucose (FDG) and positron emission tomography (PET) in the diagnosis and management of head and neck cancer. Several prospective series,-including 159 newly diagnosed and previously untreated and 23 previously irradiated head and neck squamous cell carcinoma patients initially seen at the Wake Forest University Medical Center and evaluated by clinical examination, conventional computed tomography/ magnetic resonance imaging (CT/MRI) scans, PET scans, and histopathologic studies,-were reviewed and the findings summarized for comparison of the correct differentiation of primary and metastatic cancers and for postirradiation tumor clearance in a subsegment of those cases. Positron emission tomography scanning using a fluorine-labeled deoxyglucose (FDG) radiotracer proved as reliable as conventional scanning for primary and metastatic tumor identification. Compared with clinical examination, PET was better for identification of nodal metastatic tumors but poorer for small primary tumors. For previously irradiated patients treated at least 4 months before the test, PET scanning was clearly superior to clinical examination and conventional imaging in differentiating tumor recurrence from soft-tissue irradiation effects. Fluorine-labeled deoxyglucose-PET scanning is comparable to conventional imaging of head and neck cancers in detecting primary and metastatic carcinoma. Lack of anatomic detail remains its major drawback. Currently, its greatest role is in the evaluation of the postradiotherapy patient.

Determination of the heat of hydride formation/decomposition by high-pressure differential scanning calorimetry (HP-DSC).

PubMed

Rongeat, Carine; Llamas-Jansa, Isabel; Doppiu, Stefania; Deledda, Stefano; Borgschulte, Andreas; Schultz, Ludwig; Gutfleisch, Oliver

2007-11-22

Among the thermodynamic properties of novel materials for solid-state hydrogen storage, the heat of formation/decomposition of hydrides is the most important parameter to evaluate the stability of the compound and its temperature and pressure of operation. In this work, the desorption and absorption behaviors of three different classes of hydrides are investigated under different hydrogen pressures using high-pressure differential scanning calorimetry (HP-DSC). The HP-DSC technique is used to estimate the equilibrium pressures as a function of temperature, from which the heat of formation is derived. The relevance of this procedure is demonstrated for (i) magnesium-based compounds (Ni-doped MgH2), (ii) Mg-Co-based ternary hydrides (Mg-CoHx) and (iii) Alanate complex hydrides (Ti-doped NaAlH4). From these results, it can be concluded that HP-DSC is a powerful tool to obtain a good approximation of the thermodynamic properties of hydride compounds by a simple and fast study of desorption and absorption properties under different pressures.

Melting temperature and enthalpy variations of phase change materials (PCMs): a differential scanning calorimetry (DSC) analysis

NASA Astrophysics Data System (ADS)

Sun, Xiaoqin; Lee, Kyoung Ok; Medina, Mario A.; Chu, Youhong; Li, Chuanchang

2018-06-01

Differential scanning calorimetry (DSC) analysis is a standard thermal analysis technique used to determine the phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy of phase change materials (PCMs). To determine the appropriate heating rate and sample mass, various DSC measurements were carried out using two kinds of PCMs, namely N-octadecane paraffin and calcium chloride hexahydrate. The variations in phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy were observed within applicable heating rates and sample masses. It was found that the phase transition temperature range increased with increasing heating rate and sample mass; while the heat of fusion varied without any established pattern. The specific heat decreased with the increase of heating rate and sample mass. For accuracy purpose, it is recommended that for PCMs with high thermal conductivity (e.g. hydrated salt) the focus will be on heating rate rather than sample mass.

Structural, Morphological, Differential Scanning Calorimetric and Thermogravimetric Studies of Ball Milled Fe Doped Nanoscale La0.67Sr0.33MnO3 Manganite

NASA Astrophysics Data System (ADS)

Astik, Nidhi; Jha, Prafulla K.; Pratap, Arun

2018-03-01

The ball milling route has been used to produce the La0.67Sr0.33Mn0.85Fe0.15O3 (LSMFO) nanocrystalline sample from oxide precursors. The sample was characterized using x-ray diffraction (XRD), a scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDAX), differential scanning calorimetry (DSC) and thermogravimetric (TGA) measurements. The x-ray diffraction confirms the phase purity of sample and shows that the sample crystallizes in the rhombohedral perovskite structure with a R-3c space group. The scanning electron micrograph shows the presence of well-faceted crystallites of LSMFO. The EDAX spectrum demonstrates the molar ratio of different elements of nanocrystalline LSMFO. Furthermore, the crystallite size using the Debye-Scherrer formula and William-Hall analysis has been found as 24 nm and 29 nm, respectively. Our results support the idea that a good quality nanocrystalline LSMFO sample can be obtained using the ball milling route. We also discuss the DSC and TGA curves and analyse the results in terms of phase transition, calcination temperature and activation barrier energies.

Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyzer (TEGA)

NASA Technical Reports Server (NTRS)

Musselwhite, D. S.; Boynton, W. V.; Ming, Douglas W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

2000-01-01

Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current C development and cutting edge research. The Thermal Evolved Gas Analyzer (MGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil.

Demonstration of intermediate cells during human prostate epithelial differentiation in situ and in vitro using triple-staining confocal scanning microscopy.

PubMed

van Leenders, G; Dijkman, H; Hulsbergen-van de Kaa, C; Ruiter, D; Schalken, J

2000-08-01

In human prostate epithelium, morphologically basal and luminal cells can be discriminated. The basal cell layer that putatively contains progenitor cells of the secretory epithelium is characterized by the expression of keratins (K) 5 and 14. Luminal cells represent the secretory compartment of the epithelium and express K8 and 18. We developed a technique for the simultaneous analysis of K5, 14, and 18 to identify intermediate cell stages in the prostate epithelium and to study the dynamic aspects of its differentiation in vitro. Nonmalignant prostate tissue and primary epithelial cultures were immunohistochemically characterized using triple staining with antibodies for K5, K14, and K18. Antibodies for K18 and K5 were conjugated directly with fluorochromes Alexa 488 and 546. K14 was visualized indirectly with streptavidin-Cy5. Keratin expression was analyzed by confocal scanning microscopy. The occurrence of exocrine and neuroendocrine differentiation in culture was determined via antibodies to prostate-specific antigen (PSA), chromogranin A, and serotonin. We found that basal cells expressed either K5(++)/14(++)/18+ or K5(++)/18+. The majority of luminal cells expressed K18(++), but colocalization of K5+/18(++) were recognized. Epithelial monolayer cultures predominantly revealed the basal cell phenotype K5(++)/14(++)/18+, whereas intermediate subpopulations expressing K5+/14+/18(++) and K5+/18(++) were also identified. On confluence, differentiation was induced as multicellular gland-like buds, and extensions became evident on top of the monolayer. These structures were composed of K18(++)- and K5+/18(+)-positive cell clusters surrounded by phenotypically basal cells. Few multicellular structures and cells in the monolayer showed exocrine differentiation (PSA+), but expression of chromogranin A and serotonin was absent. We conclude that simultaneous evaluation of keratin expression is useful for analyzing epithelial differentiation in the prostate. During this

Differential scanning calorimetric study of nonionic surfactant mixtures with a room temperature ionic liquid, bmimBF4.

PubMed

Inoue, Tohru; Higuchi, Yuka; Misono, Takeshi

2009-10-01

The melting behavior of polyethyleneglycol dodecyl ethers (C(12)E(6), C(12)E(7), and C(12)E(8)) in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), was investigated by means of differential scanning calorimetry (DSC). The melting temperature as a function of the surfactant concentration, combined with the cmc curve and cloud point curve, provided phase diagrams for the surfactant/bmimBF(4) mixtures in solvent-rich region. The characteristic feature of the mixtures is an existence of the Krafft temperature which is usually not observed with aqueous solutions of nonionic surfactants. The heat of fusion as a function of the surfactant concentration provided the interaction energy between the surfactant and bmimBF(4). The interaction energy shows a linear dependence on the length of polyoxyethylene (POE) chain of the surfactants, which suggests that the solvation takes place around the POE chain.

Gravimetric analysis and differential scanning calorimetric studies on glycerin-induced skin hydration.

PubMed

Lee, Ae-Ri Cho; Moon, Hee Kyung

2007-11-01

A thermal gravimetric analysis (TGA) and a differential scanning calorimetry (DSC) were carried out to characterize the water property and an alteration of lipid phase transition of stratum corneum (SC) by glycerin. In addition, the relationship between steady state skin permeation rate and skin hydration in various concentrations of glycerin was investigated. Water vapor absorption-desorption was studied in the hairless mouse stratum corneum. Dry SC samples were exposed to different conc. of glycerin (0-50%) followed by exposure to dry air and the change in weight property was monitored over time by use of TGA. In DSC study, significant decrease in DeltaH of the lipid transition in 10% glycerin and water treated sample: the heat of lipid transition of normal, water, 10% glycerin treated SC were 6.058, 4.412 and 4.316 mJ/mg, respectively. In 10% glycerin treated SCs, the Tc of water shifts around 129 degrees C, corresponding to the weakly bound secondary water. In 40% glycerin treated SC, the Tc of water shifts to 144 degrees C corresponding to strongly bound primary water. There was a good correlation between the hydration property of the skin and the steady state skin flux with the correlation coefficient (r2=0.94). As the hydration increased, the steady state flux increased. As glycerin concentration increased, hydration property decreased. High diffusivity induced by the hydration effect of glycerin and water could be the major contributing factor for the enhanced skin permeation of nicotinic acid (NA).

Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyser (TEGA)

NASA Technical Reports Server (NTRS)

Musselwhite, D. S.; Boynton, W. V.; Ming, D. W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

2000-01-01

Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current development and cutting edge research. The Thermal Evolved Gas Analyzer (TEGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil. Additional information is available in the original extended abstract.

Multitip scanning bio-Kelvin probe

NASA Astrophysics Data System (ADS)

Baikie, I. D.; Smith, P. J. S.; Porterfield, D. M.; Estrup, P. J.

1999-03-01

We have developed a novel multitip scanning Kelvin probe which can measure changes in biological surface potential ΔVs to within 2 mV and, quasisimultaneously monitor displacement to <1 μm. The control and measurement subcomponents are PC based and incorporate a flexible user interface permitting software control of each individual tip, measurement, and scan parameters. We review the mode of operation and design features of the scanning bio-Kelvin probe including tip steering, signal processing, tip calibration, and novel tip tracking/dithering routines. This system uniquely offers both tip-to-sample spacing control (which is essential to avoid spurious changes in ΔVs due to variations in mean spacing) and a dithering routine to maintain tip orientation to the biological specimen, irrespective of the latter's movement. These features permit long term (>48 h) "active" tracking of the displacement and biopotentials developed along and around a plant shoot in response to an environmental stimulus, e.g., differential illumination (phototropism) or changes in orientation (gravitropism).

Synthesis and interaction of sterol-uridine conjugate with DMPC liposomes studied by differential scanning calorimetry.

PubMed

Escobar, Jhon Fernando Berrío; Restrepo, Manuel Humberto Pastrana; Fernández, Diana Margarita Márquez; Martínez, Alejandro Martínez; Giordani, Cristiano; Castelli, Francesco; Sarpietro, Maria Grazia

2018-06-01

Differential scanning calorimetry (DSC) is a thermoanalytical technique which provides information on the interaction between drugs and models of cell membranes. Studies on the calorimetric behavior of hydrated phospholipids within liposomes are employed to shed light on the changes in the physico-chemical properties when interacting with drugs. In this report, new potential anti-cancer drugs such as uridine and uridine derivatives (acetonide and its succinate), 3β-5α,8α-endoperoxide-cholestan-6-en-3-ol (5,8-epidioxicholesterol) and conjugate (uridine acetonide-epidioxicholesterol succinate) have been synthesized. Steglich esterification method using coupling agents allowed to obtain the uridine acetonide-sterol conjugate. The study on the interaction between the drugs and dimiristoyl-phophatidilcholine (DMPC) liposomes has been conducted by the use of DSC. The analysis of the DSC curves indicated that the uridine and derivatives (acetonide and its succinate) present a very soft interaction with the DMPC liposomes, whereas the 5,8-epidioxicholesterol and the conjugate showed a strong effect on the thermotropic behavior. Our results suggested that the lipophilic character of uridine acetonide-sterol conjugate improves the affinity with the DMPC liposomes. Copyright © 2018 Elsevier B.V. All rights reserved.

18F-FDG SPECT/CT in the diagnosis of differentiated thyroid carcinoma with elevated thyroglobulin and negative iodine-131 scans.

PubMed

Ma, C; Wang, X; Shao, M; Zhao, L; Jiawei, X; Wu, Z; Wang, H

2015-06-01

Aim of the present study was to investigate the usefulness of 18F-FDG SPECT/CT in differentiated thyroid cancer (DTC) with elevated serum thyroglobulin (Tg) but negative iodine-131 scan. This retrospective review of patients with DTC recurrence who had 18F-FDG SPECT/CT and 18F-FDG PET/CT for elevated serum Tg but negative iodine-131 scan (March 2007-October 2012). After total thyroidectomy followed by radioiodine ablation, 86 consecutive patients with elevated Tg levels underwent 18F-FDG SPECT/CT or 18F-FDG PET/CT. Of these, 45 patients had 18F-FDG SPECT/CT, the other 41 patients had 18F-FDG PET/CT 3-4weeks after thyroid hormone withdrawal. The results of 18F-FDG PET/CT and SPECT/CT were correlated with patient follow-up information, which included the results from subsequent imaging modalities such as neck ultrasound, MRI and CT, Tg levels, and histologic examination of surgical specimens. The diagnostic accuracy of the two imaging modalities was evaluated. In 18F-FDG SPECT/CT scans, 24 (24/45) patients had positive findings, 22 true positive in 24 patients, false positive in 2 patients, true-negative and false-negative in 6, 15 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG SPECT/CT were 59.5%, 75% and 62.2%, respectively. Twenty six patients had positive findings on 18F-FDG PET/CT scans, 23 true positive in 26 (26/41) patients, false positive in 3 patients, true-negative and false-negative in 9, 6 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 79.3%, 81.8% and 78.1%, respectively. Clinical management changed for 13 (29%) of 45 patients by 18F-FDG SPECT/CT, 14 (34%) of 41 patients by 18F-FDG PET/CT including surgery, radiation therapy, or multikinase inhibitor. Based on the retrospective analysis of 86 patients, 18F-FDG SPECT/CT has lower sensitivity in the diagnosis of DTC recurrence with elevated Tg and negative iodine-131scan to 18F-FDG PET/CT. The clinical application of

Crystal structure determination of new antimitotic agent bis(p-fluorobenzyl)trisulfide.

PubMed

An, Haoyun; Hu, Xiurong; Gu, Jianming; Chen, Linshen; Xu, Weiming; Mo, Xiaopeng; Xu, Wanhong; Wang, Xiaobo; Xu, Xiao

2008-01-01

The purpose of this research was to investigate the physical characteristics and crystalline structure of bis(p-fluorobenzyl)trisulfide, a new anti-tumor agent. Methods used included X-ray single crystal diffraction, X-ray powder diffraction (XRPD), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetric (DSC) and thermogravimetric (TG) analyses. The findings obtained with X-ray single crystal diffraction showed that a monoclinic unit cell was a = 12.266(1) A, b = 4.7757(4) A, c = 25.510(1) A, beta = 104.25(1) degrees ; cell volume = 1,448.4(2) A(3), Z = 4, and space group C2/c. The XRPD studies of the four crystalline samples, obtained by recrystallization from four different solvents, indicated that they had the same diffraction patterns. The diffraction pattern stimulated from the crystal structure data is in excellent agreement with the experimental results. In addition, the identical FT-IR spectra of the four crystalline samples revealed absorption bands corresponding to S-S and C-S stretching as well as the characteristic aromatic substitution. Five percent weight loss at 163.3 degrees C was observed when TG was used to study the decomposition process in the temperature range of 20-200 degrees C. DSC also allowed for the determination of onset temperatures at 60.4(1)-60.7(3) degrees C and peak temperatures at 62.1(3)-62.4(3) degrees C for the four crystalline samples studied. The results verified that the single crystal structure shared the same crystal form with the four crystalline samples investigated.

3D extrusion printing of high drug loading immediate release paracetamol tablets.

PubMed

Khaled, Shaban A; Alexander, Morgan R; Wildman, Ricky D; Wallace, Martin J; Sharpe, Sonja; Yoo, Jae; Roberts, Clive J

2018-03-01

The manufacture of immediate release high drug loading paracetamol oral tablets was achieved using an extrusion based 3D printer from a premixed water based paste formulation. The 3D printed tablets demonstrate that a very high drug (paracetamol) loading formulation (80% w/w) can be printed as an acceptable tablet using a method suitable for personalisation and distributed manufacture. Paracetamol is an example of a drug whose physical form can present challenges to traditional powder compression tableting. Printing avoids these issues and facilitates the relatively high drug loading. The 3D printed tablets were evaluated for physical and mechanical properties including weight variation, friability, breaking force, disintegration time, and dimensions and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia (USP). X-ray Powder Diffraction (XRPD) was used to identify the physical form of the active. Additionally, XRPD, Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC) were used to assess possible drug-excipient interactions. The 3D printed tablets were evaluated for drug release using a USP dissolution testing type I apparatus. The tablets showed a profile characteristic of the immediate release profile as intended based upon the active/excipient ratio used with disintegration in less than 60 s and release of most of the drug within 5 min. The results demonstrate the capability of 3D extrusion based printing to produce acceptable high-drug loading tablets from approved materials that comply with current USP standards. Copyright © 2018 Elsevier B.V. All rights reserved.

Technetium phosphate bone scan in the diagnosis of septic arthritis in childhood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sundberg, S.B.; Savage, J.P.; Foster, B.K.

1989-09-01

The technetium phosphate bone scans of 106 children with suspected septic arthritis were reviewed to determine whether the bone scan can accurately differentiate septic from nonseptic arthropathy. Only 13% of children with proved septic arthritis had correct blind scan interpretation. The clinically adjusted interpretation did not identify septic arthritis in 30%. Septic arthritis was incorrectly identified in 32% of children with no evidence of septic arthritis. No statistically significant differences were noted between the scan findings in the septic and nonseptic groups and no scan findings correlated specifically with the presence or absence of joint sepsis.

Investigation of the effect of hydroxypropyl methylcellulose on the phase transformation and release profiles of carbamazepine-nicotinamide cocrystal.

PubMed

Li, Mingzhong; Qiu, Shi; Lu, Yan; Wang, Ke; Lai, Xiaojun; Rehan, Mohammad

2014-09-01

The aim of this work was to investigate the influence of hydroxypropyl methylcellulose (HPMC) on the phase transformation and release profile of carbamazepine-nicotinamide (CBZ-NIC) cocrystal in solution and in sustained release matrix tablets. The polymorphic transitions of the CBZ-NIC cocrystal and its crystalline properties were examined by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Raman spectroscopy, and scanning electron microscopy (SEM). The apparent CBZ solubility and dissolution rate of CBZ-NIC cocrystal were constant in different concentrations of HPMC solutions. In a lower percentage of HPMC in the matrix tablets, the CBZ release profile of the CBZ-NIC cocrystal was nonlinear and declined over time. With an increased HPMC content in the tablets, the CBZ-NIC cocrystal formulation showed a significantly higher CBZ release rate in comparison with the other two formulations of CBZ III and the physical mixture. Because of a significantly improved dissolution rate of the CBZ-NIC cocrystal, the rate of CBZ entering into solution is significantly faster than the rate of formation of the CBZ-HPMC soluble complex in solution, leading to a higher supersaturation level of CBZ and subsequently precipitation of CBZ dihydrate.

Synthesis and Characterization of Quantum Dot-Loaded Poly(lactic-co-glycolic) Acid Nanocomposite Fibers by an Electrospinning Process.

PubMed

Ankireddy, Seshadri Reddy; Kim, Jongsung

2017-04-01

Poly(lactic-co-glycolic) acid (PLGA) is one of the most successfully developed biodegradable polymers. PLGA is a copolymer of polylactic and glycolic acid. In this work, quantum dot (QD)-loaded PLGA nanofibers were fabricated via a simple one-step electrospinning process. The surface morphology of the fibers was characterized by scanning electron microscopy (SEM). It was shown that the PLGA nanofibers had both smooth and rough surfaces with an average fiber diameter of 150 ± 25 nm and 350 ± 60 nm for the PLGA and QD-loaded PLGA nanofibers, respectively. The needle size, applied voltage, and solvent flow rate in the syringe were maintained at 23 G, 20 kV, and 1.5 mL/h, respectively. The SEM analysis showed that nanofibers with a very thin and uniform size were formed and the InP/ZnS QDs were homogeneously loaded into the PLGA nanofiber matrix. The thermal properties of the PLGA-QD nanofibers were explored by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The surface chemical structure and functionalities were characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray powder diffraction (XRPD).

Solid state characterization of dehydroepiandrosterone.

PubMed

Chang, L C; Caira, M R; Guillory, J K

1995-10-01

Three polymorphs (forms I-III), a monohydrate (form S2), and three new solvates [4:1 hydrate (form S1), monohydrate (form S3), and methanol half-solvate (form S4)] were isolated and characterized by X-ray powder diffractometry (XRPD), IR spectroscopy, differential scanning calorimetry (DSC), hot stage microscopy, solution calorimetry, and their dissolution rates. A new polymorph, designated as form V, melting at 146.5-148 degrees C, was observed by hot stage microscopy. Our results indicate that only forms I and S4 exhibit reproducible DSC thermograms. Five of the isolated modifications undergo phase transformation on heating, and their DSC thermograms are not reproducible. Interpretation of DSC thermograms was facilitated by use of hot stage microscopy. The identification of each modification is based on XRPD patterns (except forms S3 and S4, for which the XRPD patterns are indistinguishable) and IR spectra. In the IR spectra, a significant difference was observed in the OH stretching region of all seven modifications. In a purity determination study, 5% of a contaminant modification in binary mixtures of several modifications could be detected by use of XRPD. To obtain a better understanding of the thermodynamic properties of these modifications, a series of increasing heating rates and different pan types were used in DSC. According to Burger's rule, forms I-III are monotropic polymorphs with decreasing stability in the order form I > form II > form III. The melting onsets and heats of fusion for forms I-III are 149.1 degrees C, 25.5 kJ/mol; 140.8 degrees C, 24.6 kJ/mol; and 137.8 degrees C, 24.0 kJ/mol, respectively. For form III the heat of fusion was calculated from heat of solution and DSC data. In the case of form S1 the melting point, 127.2 degrees C, was obtained by DSC using a hermetically sealed pan. The relative stabilities of the six modifications stored under high humidity conditions were predicted to be, on the basis of the heat of solution and

A hybrid scanning force and light microscope for surface imaging and three-dimensional optical sectioning in differential interference contrast.

PubMed

Stemmer, A

1995-04-01

The design of a scanned-cantilever-type force microscope is presented which is fully integrated into an inverted high-resolution video-enhanced light microscope. This set-up allows us to acquire thin optical sections in differential interference contrast (DIC) or polarization while the force microscope is in place. Such a hybrid microscope provides a unique platform to study how cell surface properties determine, or are affected by, the three-dimensional dynamic organization inside the living cell. The hybrid microscope presented in this paper has proven reliable and versatile for biological applications. It is the only instrument that can image a specimen by force microscopy and high-power DIC without having either to translate the specimen or to remove the force microscope. Adaptation of the design features could greatly enhance the suitability of other force microscopes for biological work.

Heat resistance of viable but non-culturable Escherichia coli cells determined by differential scanning calorimetry.

PubMed

Castro-Rosas, Javier; Gómez-Aldapa, Carlos Alberto; Villagómez Ibarra, José Roberto; Santos-López, Eva María; Rangel-Vargas, Esmeralda

2017-10-16

Several reports have suggested that the viable but non-culturable (VBNC) state is a resistant form of bacterial cells that allows them to remain in a dormant form in the environment. Nevertheless, studies on the resistance of VBNC bacterial cells to ecological factors are limited, mainly because techniques that allow this type of evaluation are lacking. Differential scanning calorimetry (DSC) has been used to study the thermal resistance of culturable bacteria but has never been used to study VBNC cells. In this work, the heat resistance of Escherichia coli cells in the VBNC state was studied using the DSC technique. The VBNC state was induced in E. coli ATCC 25922 by suspending bacterial cells in artificial sea water, followed by storage at 3 ± 2°C for 110 days. Periodically, the behaviour of E. coli cells was monitored by plate counts, direct viable counts and DSC. The entire bacterial population entered the VBNC state after 110 days of storage. The results obtained with DSC suggest that the VBNC state does not confer thermal resistance to E. coli cells in the temperature range analysed here. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Clinical determinants of fluorodeoxyglucose positron emission tomography/computed tomography in differentiated thyroid cancer patients with elevated thyroglobulin and negative (131)iodine whole body scans after (131)iodine therapy.

PubMed

Shamim, Syed Ejaz; Nang, Lee Boon; Shuaib, Ibrahim Lutfi; Muhamad, Nor Asiah

2014-05-01

A cross-sectional prospective study has been conducted on differentiated thyroid cancer (DTC) patients using negative (131)Iodine ((131)I) whole body scans and elevated thyroglobulin (Tg) levels. The main objective of this research was to determine the prevalence of the conversion of differentiated to dedifferentiated thyroid cancer patients during follow up at the Hospital Kuala Lumpur. It has been demonstrated that fluorodeoxyglucose (FDG) uptake is inversely proportional to the iodine concentration and to differentiation of the cells. Thirty-five patients with histologically proven DTC that have undergone total or near total thyroidectomy, and post (131)I radioactive iodine ablation therapy, were selected and prospectively analysed. The patients also had to show at least one negative whole body scan and Tg levels of 10 μg/L and above. The results of the FDG-Positron Emission Tomography/Computed Tomography (PET/CT) were then studied to determine the association and the predictors influencing the outcome by using univariable and multivariable analyses. Out of the thirty-five patients, 60% of them (twenty-one) showed positive results and 40% (fourteen) showed negative. Age, gender, and type of histopathology (HPE) showed significant associations with the positive results of the FDG-PET/CT. The results also showed no correlations observed between the Tg levels and standardised uptake value (SUV)max in the DTC patients with positive disease findings in the FDG-PET/CT. The predictor for this study was age. The prevalence of the conversion of differentiated to dedifferentiated thyroid cancer among patients with negative (131)I and elevated Tg was 60%, with age as the predictor. DTC patients aged 45 year-old and older were seven times more likely to have positive results of FDG-PET/CT imaging.

Clinical Determinants of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Differentiated Thyroid Cancer Patients with Elevated Thyroglobulin and Negative 131Iodine Whole Body Scans after 131Iodine Therapy

PubMed Central

SHAMIM, Syed Ejaz; NANG, Lee Boon; SHUAIB, Ibrahim Lutfi; MUHAMAD, Nor Asiah

2014-01-01

Background: A cross-sectional prospective study has been conducted on differentiated thyroid cancer (DTC) patients using negative 131Iodine (131I) whole body scans and elevated thyroglobulin (Tg) levels. The main objective of this research was to determine the prevalence of the conversion of differentiated to dedifferentiated thyroid cancer patients during follow up at the Hospital Kuala Lumpur. It has been demonstrated that fluorodeoxyglucose (FDG) uptake is inversely proportional to the iodine concentration and to differentiation of the cells. Methods: Thirty-five patients with histologically proven DTC that have undergone total or near total thyroidectomy, and post 131I radioactive iodine ablation therapy, were selected and prospectively analysed. The patients also had to show at least one negative whole body scan and Tg levels of 10 μg/L and above. The results of the FDG-Positron Emission Tomography/Computed Tomography (PET/CT) were then studied to determine the association and the predictors influencing the outcome by using univariable and multivariable analyses. Results: Out of the thirty-five patients, 60% of them (twenty-one) showed positive results and 40% (fourteen) showed negative. Age, gender, and type of histopathology (HPE) showed significant associations with the positive results of the FDG-PET/CT. The results also showed no correlations observed between the Tg levels and standardised uptake value (SUV)max in the DTC patients with positive disease findings in the FDG-PET/CT. The predictor for this study was age. Conclusion: The prevalence of the conversion of differentiated to dedifferentiated thyroid cancer among patients with negative 131I and elevated Tg was 60%, with age as the predictor. DTC patients aged 45 year-old and older were seven times more likely to have positive results of FDG-PET/CT imaging. PMID:25246834

Interaction of Environmental Moisture with Powdered Green Tea Formulations: Relationship between Catechin Stability and Moisture-Induced Phase Transformations

PubMed Central

Ortiz, Julieta; Kestur, Umesh S.; Taylor, Lynne S.; Mauer, Lisa J.

2009-01-01

This study investigated the effect of phase transformations of amorphous and deliquescent ingredients on catechin stability in green tea powder formulations. Blends of amorphous green tea and crystalline sucrose, citric acid, and/or ascorbic acid were analyzed by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), dynamic water vapor sorption, water activity measurements, and high-performance liquid chromatography (HPLC) after storage for up to 12 weeks at 0–75% relative humidity (RH) and 22 °C. The glass transition temperature (Tg) of green tea was reduced to below room temperature (<22 °C) at 68% RH. Dissolution of deliquescent ingredients commenced at RH values below deliquescence points in blends with amorphous green tea, and these blends had greater water uptake than predicted by an additive model of individual ingredient moisture sorption. Catechin degradation was affected by Tg of green tea powder and both dissolution and deliquescence of citric and ascorbic acids. PMID:19489621

Microstructure characterization of a food-grade U-type microemulsion system by differential scanning calorimetry and electrical conductivity techniques.

PubMed

Zhang, Hui; Taxipalati, Maierhaba; Que, Fei; Feng, Fengqin

2013-12-01

The microstructure transitions of a food-grade U-type microemulsion system containing glycerol monolaurate and propionic acid at a 1:1 mass ratio as oil phase and Tween 80 as surfactant were investigated along a water dilution line at a ratio of 80:20 mass% surfactant/oil phase, based on a previously studied phase diagram. From the water thermal behaviours detected by differential scanning calorimetry, three structural regions are identified along the dilution line. In the first region, all water molecules are confined to the water core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, transforms into bicontinuous in the second region, and finally the microemulsion become o/w in the third region. The thermal transition points coincide with the structural phase transitions by electrical conductivity measurements, indicating that the structural transitions occur at 35 and 65 mass% of water along the dilution line. Copyright © 2013 Elsevier Ltd. All rights reserved.

A study of mercuric iodide near melting using differential scanning calorimetry, Raman spectroscopy and X-ray diffraction

NASA Astrophysics Data System (ADS)

Burger, A.; Morgan, S.; Jiang, H.; Silberman, E.; Schieber, M.; Van Den Berg, L.; Keller, L.; Wagner, C. N. J.

1989-11-01

High-temperature studies of mercuric iodide (HgI2) involving differential scanning calorimetry (DSC), Raman spectroscopy and X-ray powder diffraction have failed to confirm the existence of a red-colored tetragonal high-temperature phase called α'-HgI2 reported by S.N. Toubektsis et al. [J. Appl. Phys. 58 (1988) 2070] using DSC measurements. The multiple DSC peaks near melting reported by Toubektsis are found by the present authors only if the sample is heated in a stainless-steel container. Using a Pyrex container or inserting a platinum foil between the HgI2 and the stainless-steel container yields only one sharp, single DSC peak at the melting point. The nonexistence of the α' phase is confirmed by high-temperature X-ray diffraction and Raman spectroscopy performed in the vicinity of the melting point. These methods clearly, indicate the existence of only the yellow orthorhombic β-HgI2 phase. The experimental high-temperature DSC, Raman and X-ray diffraction data are presented and discussed.

Phoenix Lander's Thermal Evolved Gas Analyzer: Differential Scanning Calorimeter and Mass Spectrometer Database Development

NASA Technical Reports Server (NTRS)

Sutter, B.; Lauer, H. V.; Golden, D. C.; Ming, D. W.; Boynton, W. V.

2008-01-01

The Mars Scout Phoenix lander will land in the north polar region of Mars in May, 2008. One objective of the Phoenix lander is to search for evidence of past life in the form of molecular organics that may be preserved in the subsurface soil. The Thermal Evolved Gas Analyzer (TEGA) was developed to detect these organics by coupling a simultaneous differential thermal analyzer (SDTA) with a mass spectrometer. Martian soil will be heated to approx.1000 C and potential organic decomposition products such as CO2, CH4 etc. will be examined for with the MS. TEGA s SDTA will also assess the presence of endothermic and exothermic reactions that are characteristic of soil organics and minerals as the soil is heated. The MS in addition to detecting organic decompositon products, will also assess the levels of soil inorganic volatiles such as H2O, SO2, and CO2. Organic detection has a high priority for this mission; however, TEGA has the ability to provide valuable insight into the mineralogical composition of the soil. The overall goal of this work is to develop a TEGA database of minerals that will serve as a reference for the interpretation of Phoenix-TEGA. Previous databases for the ill-fated Mars Polar Lander (MPL)-TEGA instrument only went to 725 C. Furthermore, the MPL-TEGA could only detect CO2 and H2O while the Phoenix-TEGA MS can examine up to 144 atomic mass units. The higher temperature Phoenix-TEGA SDTA coupled with the more capable MS indicates that a higher temperature database is required for TEGA interpretation. The overall goal of this work is to develop a differential scanning calorimeter (DSC) database of minerals along with corresponding MS data of evolved gases that can used to interpret TEGA data during and after mission operations. While SDTA and DSC measurement techniques are slightly different (SDTA does not use a reference pan), the results are fundamentally similar and thus DSC is a useful technique in providing comparative data for the TEGA

Thyroglobulin levels and thyroglobulin doubling time independently predict a positive 18F-FDG PET/CT scan in patients with biochemical recurrence of differentiated thyroid carcinoma.

PubMed

Giovanella, Luca; Trimboli, Pierpaolo; Verburg, Frederik A; Treglia, Giorgio; Piccardo, Arnoldo; Foppiani, Luca; Ceriani, Luca

2013-06-01

To assess the relationship between serum thyroglobulin (Tg) levels, Tg doubling time (Tg-DT) and the diagnostic performance of (18)F-FDG PET/CT in detecting recurrences of (131)I-negative differentiated thyroid carcinoma (DTC). Included in the present study were 102 patients with DTC. All patients were treated by thyroid ablation (e.g. thyroidectomy and (131)I), and underwent (18)F-FDG PET/CT due to detectable Tg levels and negative conventional imaging. Consecutive serum Tg measurements performed before the (18)F-FDG PET/CT examination were used for Tg-DT calculation. The (18)F-FDG PET/CT results were assessed as true or false after histological and/or clinical follow-up. Serum Tg levels were higher in patients with a positive (18)F-FDG PET/CT scan (median 6.7 ng/mL, range 0.7-73.6 ng/mL) than in patients with a negative scan (median 1.8 ng/mL, range 0.5-4.9 ng/mL; P < 0.001). In 43 (88 %) of 49 patients with a true-positive (18)F-FDG PET/CT scan, the Tg levels were >5.5 ng/mL, and in 31 (74 %) of 42 patients with a true-negative (18)F-FDG PET/CT scan, the Tg levels were ≤5.5 ng/mL. A Tg-DT of <1 year was found in 46 of 49 patients (94 %) with a true-positive (18)F-FDG PET/CT scan, and 40 of 42 patients (95 %) with a true-negative scan had a stable or increased Tg-DT. Moreover, combining Tg levels and Tg-DT as selection criteria correctly distinguished between patients with a positive and a negative scan (P<0.0001). The accuracy of (18)F-FDG PET/CT significantly improves when the serum Tg level is above 5.5 ng/mL during levothyroxine treatment or when the Tg-DT is less than 1 year, independent of the absolute value.

Differential investment in body girths by sex: Evidence from 3D photonic scanning in a Thai cohort.

PubMed

Shirley, Meghan K; Cole, Tim J; Charoensiriwath, Supiya; Treleaven, Philip; Wells, Jonathan C K

2017-08-01

Life history trade-offs may manifest between competing organs and tissues in the body. Sexual dimorphism in tissue investment is well-established in humans, with sex-associated body shape differences linked to natural and sexual selection. This study uses three-dimensional (3D) photonic scanning to test whether males and females differentially invest energy in various body regions in relation to two independent proxies of growth. Body shape data (multiple girths) came from a Thai cohort (n = 11,610; 53% female; age range 21-88 years). Weight was considered a proxy for recent energy acquisition. Stature represented completed growth, a proxy for energy acquisition earlier in life. The data were analyzed using growth-proxy by sex interaction log-log regression models adjusting for age, salary and number of children. For a given percentage increase in weight, females showed greater percentage increases than males in girths of the arm, chest, hip, thigh, knee and calf (p < 0.001), whilst males exceeded females in head and waist girths (also p < 0.001). For a given percentage increase in height, weight and all girths showed greater proportional changes in males than females (p < 0.001). These results indicate sex-specific life history strategies wherein the direction and timing of energy investment in girths varies between the sexes. The results add to literature suggesting that sexual dimorphism in body morphology is not a fixed trait; rather, differential energy allocation to specific body regions appears to be a plastic strategy adjusted in relation to energy acquisition across the life course. © 2017 Wiley Periodicals, Inc.

Homogeneity of ball milled ceramic powders: Effect of jar shape and milling conditions.

PubMed

Broseghini, M; D'Incau, M; Gelisio, L; Pugno, N M; Scardi, P

2017-02-01

This paper contains data and supporting information of and complementary to the research article entitled " Effect of jar shape on high-energy planetary ball milling efficiency: simulations and experiments " (Broseghini et al.,) [1]. Calcium fluoride (CaF 2 ) was ground using two jars of different shape (cylindrical and half-moon) installed on a planetary ball-mill, exploring different operating conditions (jar-to-plate angular velocity ratio and milling time). Scanning Electron Microscopy (SEM) images and X-Ray Powder Diffraction data (XRPD) were collected to assess the effect of milling conditions on the end-product crystallite size. Due to the inhomogeneity of the end product, the Whole Powder Pattern Model (WPPM, (Scardi, 2008) [2]) analysis of XRPD data required the hypothesis of a bimodal distribution of sizes - respectively ground (fine fraction) and less-to-not ground (coarse fraction) - confirmed by SEM images and suggested by the previous literature (Abdellatief et al., 2013) [3,4]. Predominance of fine fraction clearly indicates optimal milling conditions.

Are developments in mental scanning and mental rotation related?

PubMed Central

Wimmer, Marina C.; Robinson, Elizabeth J.; Doherty, Martin J.

2017-01-01

The development and relation of mental scanning and mental rotation were examined in 4-, 6-, 8-, 10-year old children and adults (N = 102). Based on previous findings from adults and ageing populations, the key question was whether they develop as a set of related abilities and become increasingly differentiated or are unrelated abilities per se. Findings revealed that both mental scanning and rotation abilities develop between 4- and 6 years of age. Specifically, 4-year-olds showed no difference in accuracy of mental scanning and no scanning trials whereas all older children and adults made more errors in scanning trials. Additionally, the minority of 4-year-olds showed a linear increase in response time with increasing rotation angle difference of two stimuli in contrast to all older participants. Despite similar developmental trajectories, mental scanning and rotation performances were unrelated. Thus, adding to research findings from adults, mental scanning and rotation appear to develop as a set of unrelated abilities from the outset. Different underlying abilities such as visual working memory and spatial coding versus representing past and future events are discussed. PMID:28207810

Selenomethionine Se 75 thymus scans in myasthenia gravis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toole, J.F.; Cowan, R.; Maynard, D.

1975-01-01

In 1966, Toole and Witcofski introduced selenomethionine Se 75 mediastinal scanning as a diagnostic test for thymomas. Since then we have performed such scans on patients with myasthenic syndrome. Because the technique is atraumatic, safe, and accurate, it can be performed on critically ill myasthenics. Two hundred and fifty microcuries of selenomethionine Se 75 is injected intravenously. Within 1 hour the mediastinum from the suprasternal notch to the ziphoid process is scanned, using a 2 x 3 inch scanner. Delayed scans have been made in a few instances but they have not increased the number of positive cases. Selenomethionine Semore » 75 is incorporated into tissues undergoing rapid protein synthesis such as thyroid, pancreas, liver, and lymphomas. Of the 34 mediastinal scans performed on myasthenics between 1966 and December 31, 1974, 4 were positive for thymoma. In addition, there was a positive scan with uptake in an area of atelectasis of the lung adjacent to the mediastinum. Of interest is the fact that 1 patient with carcinoma of the lung had a positive scan over the lesion. In 13 patients with chronic lymphatic leukemia the mediastinal scans were negative. In another patient with a mediastinal mass noted on chest x-ray, a variety of differential diagnostic possibilities were considered, such as pericardial cyst, dermoid, and aneurysm. A selenomethionine scan was strongly positive, suggesting a thymoma which subsequent surgery confirmed.« less

Melting, crystallization and storage stability of virgin coconut oil and its blends by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR).

PubMed

Srivastava, Yashi; Semwal, Anil Dutt; Sajeevkumar, Vallayil Appukuttan; Sharma, G K

2017-01-01

The blends were prepared of virgin coconut oil with refined soyabean oil (VCO-RSOY) and refined safflower oil (VCO-RSAFF). Blending with VCO improved the fatty acid composition which increased the shelf stability of 20:80 VCO-RSOY and VCO-RSAFF up to 12 months in different packaging systems such as low density polyethylene, linear low density polyethylene, metalized polyester pouches, polyethylene teteraphthalate, high density polyethylene (HDPE), Amber HDPE bottle. The specific spectral regions of FTIR proved to be very useful for the determination of adulteration as well as for the study of oxidation process. Band shifts observed at 3008, 1652, 1397, 1097, 912 and 845 cm -1 have been used to differentiate RSAFF from VCO. VCO spectrums did not have these chemical shifts. Further the spectrum of RSOY showed same band shifts as RSAFF except 1652, 1397, 869.6 and 845 cm -1 . Differential Scanning Calorimetry provided useful information regarding the nature of thermodynamic changes related to physical state of vegetable oil. The physical state changes included melting and crystallization events which require the intake and release of energy.

Algorithm-enabled partial-angular-scan configurations for dual-energy CT.

PubMed

Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan

2018-05-01

We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some

One-step simultaneous differential scanning calorimetry-FTIR microspectroscopy to quickly detect continuous pathways in the solid-state glucose/asparagine Maillard reaction.

PubMed

Hwang, Deng-Fwu; Hsieh, Tzu-Feng; Lin, Shan-Yang

2013-01-01

The stepwise reaction pathway of the solid-state Maillard reaction between glucose (Glc) and asparagine (Asn) was investigated using simultaneous differential scanning calorimetry (DSC)-FTIR microspectroscopy. The color change and FTIR spectra of Glc-Asn physical mixtures (molar ratio = 1:1) preheated to different temperatures followed by cooling were also examined. The successive reaction products such as Schiff base intermediate, Amadori product, and decarboxylated Amadori product in the solid-state Glc-Asn Maillard reaction were first simultaneously evidenced by this unique DSC-FTIR microspectroscopy. The color changed from white to yellow-brown to dark brown, and appearance of new IR peaks confirmed the formation of Maillard reaction products. The present study clearly indicates that this unique DSC-FTIR technique not only accelerates but also detects precursors and products of the Maillard reaction in real time.

An attempt to stabilize tanshinone IIA solid dispersion by the use of ternary systems with nano-CaCO3 and poloxamer 188.

PubMed

Yan, Hong-Mei; Zhang, Zhen-Hai; Jiang, Yan-Rong; Ding, Dong-Mei; Sun, E; Jia, Xiao-Bin

2014-04-01

Tanshinone IIA (TSIIA) on solid dispersions (SDs) has thermodynamical instability of amorphous drug. Ternary solid dispersions (tSDs) can extend the stability of the amorphous form of drug. Poloxamer 188 was used as a SD carrier. Nano-CaCO3 played an important role in adsorption of biomolecules and is being developed for a host of biotechnological applications. The aim of the present study was to investigate the dissolution behavior and accelerated stability of TSIIA on solid dispersions (SDs) by the use of ternary systems with nano-CaCO3 and poloxamer 188. The TSIIA tSDs were prepared by a spray-drying method. First, the effect of combination of poloxamer 188 and nano-CaCO3 on TSIIA dissolution was studied. Subsequently, a set of complementary techniques (DSC, XRPD, SEM and FTIR) was used to monitor the physical changes of TSIIA in the SDs. Finally, stability test was carried out under the conditions 40°C/75% RH for 6 months. The characterization of tSDs by differential scanning calorimetry analysis (DSC) and X-ray powder diffraction (XRPD) showed that TSIIA was present in its amorphous form. Fourier transforms infrared spectroscopy (FTIR) suggested the presence of interactions between TSIIA and carriers in tSDs. Improvement in the dissolution rate was observed for all SDs. The stability study conducted on SDs with nano-CaCO3 showed stable drug content and dissolution behavior, over the period of 6 months as compared with freshly prepared SDs. SDs preparation with nano-CaCO3 and poloxamer 188 may be a promising approach to enhance the dissolution and stability of TSIIA.

Assessment of degree of disorder (amorphicity) of lyophilized formulations of growth hormone using isothermal microcalorimetry.

PubMed

Mosharraf, Mitra

2004-05-01

When determining the degree of disorder of a lyophilized cake of a protein, it is important to use an appropriate analytical technique. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) are the most commonly used thermoanalytical techniques for characterizing freeze-dried protein formulations. Unfortunately, these methods are unable to detect solid-state disorder at levels < 10%. Also, interpretation of DSC results for freeze-dried protein formulations can be difficult, as a result of the more complex thermal events occurring with this technique. For example, proteins can inhibit the thermally induced recrystallization of the lyophilized cake, resulting in potential misinterpretation of DSC degree of disorder results. The aim of this investigation was to study the use of isothermal microcalorimetry (IMC) in the assessment of degree of solid-state disorder (amorphicity) of lyophilized formulations of proteins. For this purpose, two formulations of growth hormone were prepared by lyophilization. These formulations consisted of the same amounts of protein, mannitol, glycine, and phosphate buffer, but differed in the freeze-drying procedure. After lyophilization, the recrystallization of the samples was studied using IMC at 25 degrees C under different relative humidities (58-75%). The effect of available surface area was studied by determining the heat of recrystallization (Q) of the samples before and after disintegration of the cakes. The results showed that, in contrast to DSC, IMC allowed detection of the recrystallization event in the formulations. Although both formulations were completely disordered and indistinguishable according to XRPD method, IMC revealed that formulation B had a different solid-sate structure than formulation A. This difference was the result of differences in the freeze-drying parameters, demonstrating the importance of choosing appropriate analytical methodology.

Rheological Behavior, Granule Size Distribution and Differential Scanning Calorimetry of Cross-Linked Banana (Musa paradisiaca) Starch.

NASA Astrophysics Data System (ADS)

Núñez-Santiago, María C.; Maristany-Cáceres, Amira J.; Suárez, Francisco J. García; Bello-Pérez, Arturo

2008-07-01

Rheological behavior at 60 °C, granule size distribution and Differential Scanning Calorimetry (DSC) tests were employed to study the effect of diverse reaction conditions: adipic acid concentration, pH and temperature during cross-linking of banana (Musa paradisiaca) starch. These properties were determined in native banana starch pastes for the purpose of comparison. Rheological behavior from pastes of cross-linked starch at 60 °C did not show hysteresis, probably due the cross-linkage of starch that avoided disruption of granules, elsewhere, native starch showed hysteresis in a thixotropic loop. All pastes exhibited non-Newtonian shear thinning behavior. In all cases, size distribution showed a decrease in the median diameter in cross-linked starches. This condition produces a decrease in swelling capacity of cross-linked starch. The median diameter decreased with an increase of acid adipic concentration; however, an increase of pH and Temperature produced an increase in this variable. Finally, an increase in gelatinization temperature and entalphy (ΔH) were observed as an effect of cross-linkage. An increase in acid adipic concentration produced an increase in Tonset and a decrease in ΔH. pH and temperature. The cross-linked of banana starch produced granules more resistant during the pasting procedure.

Optimization of glibenclamide tablet composition through the combined use of differential scanning calorimetry and D-optimal mixture experimental design.

PubMed

Mura, P; Furlanetto, S; Cirri, M; Maestrelli, F; Marras, A M; Pinzauti, S

2005-02-07

A systematic analysis of the influence of different proportions of excipients on the stability of a solid dosage form was carried out. In particular, a d-optimal mixture experimental design was applied for the evaluation of glibenclamide compatibility in tablet formulations, consisting of four classic excipients (natrosol as binding agent, stearic acid as lubricant, sorbitol as diluent and cross-linked polyvinylpyrrolidone as disintegrant). The goal was to find the mixture component proportions which correspond to the optimal drug melting parameters, i.e. its maximum stability, using differential scanning calorimetry (DSC) to quickly obtain information about possible interactions among the formulation components. The absolute value of the difference between the melting peak temperature of pure drug endotherm and that in each analysed mixture and the absolute value of the difference between the enthalpy of the pure glibenclamide melting peak and that of its melting peak in the different analyzed mixtures, were chosen as indexes of the drug-excipient interaction degree.

High-resolution resonant and nonresonant fiber-scanning confocal microscope.

PubMed

Hendriks, Benno H W; Bierhoff, Walter C J; Horikx, Jeroen J L; Desjardins, Adrien E; Hezemans, Cees A; 't Hooft, Gert W; Lucassen, Gerald W; Mihajlovic, Nenad

2011-02-01

We present a novel, hand-held microscope probe for acquiring confocal images of biological tissue. This probe generates images by scanning a fiber-lens combination with a miniature electromagnetic actuator, which allows it to be operated in resonant and nonresonant scanning modes. In the resonant scanning mode, a circular field of view with a diameter of 190 μm and an angular frequency of 127 Hz can be achieved. In the nonresonant scanning mode, a maximum field of view with a width of 69 μm can be achieved. The measured transverse and axial resolutions are 0.60 and 7.4 μm, respectively. Images of biological tissue acquired in the resonant mode are presented, which demonstrate its potential for real-time tissue differentiation. With an outer diameter of 3 mm, the microscope probe could be utilized to visualize cellular microstructures in vivo across a broad range of minimally-invasive procedures.

Effect of polyglycerol esters additive on palm oil crystallization using focused beam reflectance measurement and differential scanning calorimetry.

PubMed

Saw, M H; Hishamuddin, E; Chong, C L; Yeoh, C B; Lim, W H

2017-01-01

The effect of 0.1-0.7% (w/w) of polyglycerol esters (PGEmix-8) on palm oil crystallization was studied using focused beam reflectance measurement (FBRM) to analyze the in-line changes of crystal size distribution during the crystallization. FBRM results show that 0.1-0.5% (w/w) of PGEmix-8 did not significantly affect nucleation but slightly retarded crystal growth. The use of 0.7% (w/w) additive showed greater heterogeneous nucleation compared to those with lower dosages of additive. Crystal growth was also greatly reduced when using 0.7% (w/w) dosage. The morphological study indicated that the palm oil crystals were smaller and more even in size than when more additive was added. Isothermal crystallization studies using differential scanning calorimetry (DSC) showed increased inhibitory effects on palm oil crystal growth with increasing concentration of PGEmix-8. These results imply that PGEmix-8 is a nucleation enhancing and crystal growth retarding additive in palm oil crystallization at 0.7% (w/w) dosage. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

cAMP-dependent protein kinase (PKA) complexes probed by complementary differential scanning fluorimetry and ion mobility–mass spectrometry

PubMed Central

Byrne, Dominic P.; Vonderach, Matthias; Ferries, Samantha; Brownridge, Philip J.; Eyers, Claire E.; Eyers, Patrick A.

2016-01-01

cAMP-dependent protein kinase (PKA) is an archetypal biological signaling module and a model for understanding the regulation of protein kinases. In the present study, we combine biochemistry with differential scanning fluorimetry (DSF) and ion mobility–mass spectrometry (IM–MS) to evaluate effects of phosphorylation and structure on the ligand binding, dynamics and stability of components of heteromeric PKA protein complexes in vitro. We uncover dynamic, conformationally distinct populations of the PKA catalytic subunit with distinct structural stability and susceptibility to the physiological protein inhibitor PKI. Native MS of reconstituted PKA R2C2 holoenzymes reveals variable subunit stoichiometry and holoenzyme ablation by PKI binding. Finally, we find that although a ‘kinase-dead’ PKA catalytic domain cannot bind to ATP in solution, it interacts with several prominent chemical kinase inhibitors. These data demonstrate the combined power of IM–MS and DSF to probe PKA dynamics and regulation, techniques that can be employed to evaluate other protein-ligand complexes, with broad implications for cellular signaling. PMID:27444646

A rapid micro quantification method of paracetamol in suppositories using differential scanning calorimetry.

PubMed

Noordin, Mohamed I; Chung, L Y

2004-01-01

This study adopts Differential Scanning Calorimetry (DSC) to analyze the thermal properties of samples (2.5-4.0 mg) from the tip, middle, and base sections of individual paracetamol suppositories, which were sampled carefully using a stainless steel scalpel. The contents of paracetamol present in the samples obtained from these sections were determined from the enthalpies of fusion of paracetamol and expressed as % w/w paracetamol to allow comparison of the amount of paracetamol found in each section. The tip, middle, and base sections contained 10.1+/-0.2%, 10.1+/-0.2%, and 10.3+/-0.2% w/w paracetamol, and are statistically similar (One-way anova; p>0.05). This indicates that the preparation technique adopted produces high quality suppositories in terms of content uniformity. The contents of paracetamol in the 120-mg paracetamol suppositories determined by DSC and UV spectrophotometry were statistically equivalent (Students's t-test; p>0.05), 120.8+/-2.6 mg and 120.8+/-1.5 mg, respectively, making DSC a clear alternative method for the measurement of content of drug in suppositories. The main advantages of the method are that samples of only 2.5-4.0 mg are required and the procedure does not require an extraction process, which allows for the analysis to be completed rapidly. In addition, it is highly sensitive and reproducible, with the lower detection limit at 4.0% w/w paracetamol, which is about 2.5 times lower than the content of paracetamol (10% w/w) present in our 120-mg paracetamol suppositories and commercial paracetamol suppositories, which contained about 125 mg paracetamol. Therefore, this method is particularly suited for determination of content uniformity in individual suppositories in quality control (QC) and in process quality control (PQC).

Comparative Study Of Various Grades Of Polyethylene By Differential Scanning Calorimetry (DSC) Correlated With Raman Spectroscopy

NASA Astrophysics Data System (ADS)

Jumeau, Richard; Bourson, Patrice; Ferriol, Michel; Lahure, François; Ducos, Franck; Ligneron, Jérôme

2011-05-01

Polyethylene (PE) is a very important material. In 2008, almost 30% of the world plastics production was dedicated to this polymer (70 million tons) [1]. It is a consumer polymer because of its moderate cost of manufacturing and its physical and mechanical properties compatible with various applications in everyday life. Indeed, PE is generally easily processable. It possesses an excellent electric insulation and shock resistance combined with a very good chemical and biological inertia [2]. For each application, there is a particular grade, i.e. a polyethylene with well defined rheological properties. Therefore, it is essential to know how to differentiate these different grades by suitable methods of characterization. Differential Scanning Calorimetry (DSC) is one of the techniques usually used for this purpose. The knowledge of characteristic temperatures such as melting, cold crystallization or glass transition gives information on the viscosity and thus, on the grade of the polymer. DSC also allows the detection of defects, (for example, presence of unmelted pieces). However DSC is a tedious method for on-line quality control, limiting its scope. The determination of the polymer structure represents a major challenge in the industrial world of polymers. Raman spectroscopy, another technique of polymer analysis, is nowadays growing fast because of the advantages it presents. It is a non-destructive method, capable of also giving useful information about the morphology of the polymer. This technique can be perfectly used in industry by means of adapted sensors and devices with more and more reduced dimensions [3]. That technique is used to obtain the characteristic temperatures of PE and information on the polymer structure. The purpose of this article is to establish the correlation between the viscosity of a polymer and its characteristic temperatures obtained by DSC and subsequent possibilities of quality control in industry. These measurements are correlated

Free Motion Scanning System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sword, Charles K.

The present invention relates to an ultrasonic scanner and method for the imaging of a part surface, the scanner comprising: a probe assembly spaced apart from the surface including at least two tracking signals for emitting electromagnetic radiation and a transmitter for emitting ultrasonic waves onto a surface in order to induce at least a portion of said waves to be reflected from the surface, at least one detector for receiving the electromagnetic radiation wherein the detector is positioned to receive said radiation from the tracking signals, an analyzing means for recognizing a three-dimensional location of the tracking signals basedmore » on said emitted electromagnetic radiation, a differential conversion means for generating an output signal representative of the waveform of the reflected waves, and a means for relating said tracking signal location with the output signal and projecting an image of the resulting data. The scanner and method are particularly useful to acquire ultrasonic inspection data by scanning the probe-over a complex part surface in an arbitrary scanning pattern.« less

Free motion scanning system

DOEpatents

Sword, Charles K.

2000-01-01

The present invention relates to an ultrasonic scanner system and method for the imaging of a part system, the scanner comprising: a probe assembly spaced apart from the surface of the part including at least two tracking signals for emitting radiation and a transmitter for emitting ultrasonic waves onto a surface in order to induce at least a portion of the waves to be reflected from the part, at least one detector for receiving the radiation wherein the detector is positioned to receive the radiation from the tracking signals, an analyzer for recognizing a three-dimensional location of the tracking signals based on the emitted radiation, a differential converter for generating an output signal representative of the waveform of the reflected waves, and a device such as a computer for relating said tracking signal location with the output signal and projecting an image of the resulting data. The scanner and method are particularly useful to acquire ultrasonic inspection data by scanning the probe over a complex part surface in an arbitrary scanning pattern.

Characterization of As-polluted soils by laboratory X-ray-based techniques coupled with sequential extractions and electron microscopy: the case of Crocette gold mine in the Monte Rosa mining district (Italy).

PubMed

Allegretta, Ignazio; Porfido, Carlo; Martin, Maria; Barberis, Elisabetta; Terzano, Roberto; Spagnuolo, Matteo

2018-06-24

Arsenic concentration and distribution were studied by combining laboratory X-ray-based techniques (wavelength dispersive X-ray fluorescence (WDXRF), micro X-ray fluorescence (μXRF), and X-ray powder diffraction (XRPD)), field emission scanning electron microscopy equipped with microanalysis (FE-SEM-EDX), and sequential extraction procedure (SEP) coupled to total reflection X-ray fluorescence (TXRF) analysis. This approach was applied to three contaminated soils and one mine tailing collected near the gold extraction plant at the Crocette gold mine (Macugnaga, VB) in the Monte Rosa mining district (Piedmont, Italy). Arsenic (As) concentration, measured with WDXRF, ranged from 145 to 40,200 mg/kg. XRPD analysis evidenced the presence of jarosite and the absence of any As-bearing mineral, suggesting a high weathering grade and strong oxidative conditions. However, small domains of Fe arsenate were identified by combining μXRF with FE-SEM-EDX. SEP results revealed that As was mainly associated to amorphous Fe oxides/hydroxides or hydroxysulfates (50-80%) and the combination of XRPD and FE-SEM-EDX suggested that this phase could be attributed to schwertmannite. On the basis of the reported results, As is scarcely mobile, even if a consistent As fraction (1-3 g As/kg of soil) is still potentially mobilizable. In general, the proposed combination of laboratory X-ray techniques could be successfully employed to unravel environmental issues related to metal(loid) pollution in soil and sediments.

Inter-satellite laser link acquisition with dual-way scanning for Space Advanced Gravity Measurements mission

NASA Astrophysics Data System (ADS)

Zhang, Jing-Yi; Ming, Min; Jiang, Yuan-Ze; Duan, Hui-Zong; Yeh, Hsien-Chi

2018-06-01

Laser link acquisition is a key technology for inter-satellite laser ranging and laser communication. In this paper, we present an acquisition scheme based on the differential power sensing method with dual-way scanning, which will be used in the next-generation gravity measurement mission proposed in China, called Space Advanced Gravity Measurements (SAGM). In this scheme, the laser beams emitted from two satellites are power-modulated at different frequencies to enable the signals of the two beams to be measured distinguishably, and their corresponding pointing angles are determined by using the differential power sensing method. As the master laser beam and the slave laser beam are decoupled, the dual-way scanning method, in which the laser beams of both the master and the slave satellites scan uncertainty cones simultaneously and independently, can be used, instead of the commonly used single-way scanning method, in which the laser beam of one satellite scans and that of the other one stares. Therefore, the acquisition time is reduced significantly. Numerical simulation and experiments of the acquisition process are performed using the design parameters of the SAGM mission. The results show that the average acquisition time is less than 10 s for a scanning range of 1-mrad radius with a success rate of more than 99%.

Robustness testing in pharmaceutical freeze-drying: inter-relation of process conditions and product quality attributes studied for a vaccine formulation.

PubMed

Schneid, Stefan C; Stärtzel, Peter M; Lettner, Patrick; Gieseler, Henning

2011-01-01

The recent US Food and Drug Administration (FDA) legislation has introduced the evaluation of the Design Space of critical process parameters in manufacturing processes. In freeze-drying, a "formulation" is expected to be robust when minor deviations of the product temperature do not negatively affect the final product quality attributes. To evaluate "formulation" robustness by investigating the effect of elevated product temperature on product quality using a bacterial vaccine solution. The vaccine solution was characterized by freeze-dry microscopy to determine the critical formulation temperature. A conservative cycle was developed using the SMART™ mode of a Lyostar II freeze dryer. Product temperature was elevated to imitate intermediate and aggressive cycle conditions. The final product was analyzed using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Karl Fischer, and modulated differential scanning calorimetry (MDSC), and the life cell count (LCC) during accelerated stability testing. The cakes processed at intermediate and aggressive conditions displayed larger pores with microcollapse of walls and stronger loss in LCC than the conservatively processed product, especially during stability testing. For all process conditions, a loss of the majority of cells was observed during storage. For freeze-drying of life bacterial vaccine solutions, the product temperature profile during primary drying appeared to be inter-related to product quality attributes.

Towards improved solubility of poorly water-soluble drugs: cryogenic co-grinding of piroxicam with carrier polymers.

PubMed

Penkina, Anna; Semjonov, Kristian; Hakola, Maija; Vuorinen, Sirpa; Repo, Timo; Yliruusi, Jouko; Aruväli, Jaan; Kogermann, Karin; Veski, Peep; Heinämäki, Jyrki

2016-01-01

Amorphous solid dispersions (SDs) open up exciting opportunities in formulating poorly water-soluble active pharmaceutical ingredients (APIs). In the present study, novel catalytic pretreated softwood cellulose (CPSC) and polyvinylpyrrolidone (PVP) were investigated as carrier polymers for preparing and stabilizing cryogenic co-ground SDs of poorly water-soluble piroxicam (PRX). CPSC was isolated from pine wood (Pinus sylvestris). Raman and Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) were used for characterizing the solid-state changes and drug-polymer interactions. High-resolution scanning electron microscope (SEM) was used to analyze the particle size and surface morphology of starting materials and final cryogenic co-ground SDs. In addition, the molecular aspects of drug-polymer interactions and stabilization mechanisms are presented. The results showed that the carrier polymer influenced both the degree of amorphization of PRX and stabilization against crystallization. The cryogenic co-ground SDs prepared from PVP showed an enhanced dissolution rate of PRX, while the corresponding SDs prepared from CPSC exhibited a clear sustained release behavior. In conclusion, cryogenic co-grinding provides a versatile method for preparing amorphous SDs of poorly water-soluble APIs. The solid-state stability and dissolution behavior of such co-ground SDs are to a great extent dependent on the carrier polymer used.

Water-mediated solid-state transformation of a polymorphic drug during aqueous-based drug-layer coating of pellets.

PubMed

Lust, Andres; Lakio, Satu; Vintsevits, Julia; Kozlova, Jekaterina; Veski, Peep; Heinämäki, Jyrki; Kogermann, Karin

2013-11-01

During aqueous drug-layer coating, drug substance(s) are exposed to water and elevated temperatures which can lead to water-mediated process induced transformations (PITs). The effects of aqueous drug-layer coating of pellets (Cellets(®)) on the anhydrous piroxicam, PRX, were investigated in the miniaturized coating equipment and with free films. Hydroxypropyl methylcellulose (HPMC) was used as a carrier coating polymer. Free films were prepared by using an in-house small-scale rotating plate system equipped with an atomization air nozzle. Raman spectroscopy, X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to characterize the solid-state properties and surface morphology of the pellets and free films. The results showed that anhydrous PRX form I (AH) and monohydrate (MH) were stable during drug-layer coating, but amorphous PRX in solid dispersion (SD) crystallized as MH already after 10 min of coating. Furthermore, the increase in a dissolution rate was achieved from the drug-layer coated inert pellets compared to powder forms. In conclusion, water-mediated solid-state PITs of amorphous PRX is evident during aqueous-based drug-layer coating of pellets, and solid-state change can be verified using Raman spectroscopy. Copyright © 2013 Elsevier B.V. All rights reserved.

Co-Processed Chitin-Mannitol as a New Excipient for Oro-Dispersible Tablets

PubMed Central

Daraghmeh, Nidal; Chowdhry, Babur Z.; Leharne, Stephen A.; Al Omari, Mahmoud M. H.; Badwan, Adnan A.

2015-01-01

This study describes the preparation, characterization and performance of a novel excipient for use in oro-dispersible tablets (ODT). The excipient (Cop–CM) consists of chitin and mannitol. The excipient with optimal physicochemical properties was obtained at a chitin: mannitol ratio of 2:8 (w/w) and produced by roll compaction (RC). Differential scanning calorimetry (DSC), Fourier transform-Infrared (FT-IR), X-ray powder diffraction (XRPD) and scanning electron microscope (SEM) techniques were used to characterize Cop–CM, in addition to characterization of its powder and ODT dosage form. The effect of particle size distribution of Cop–CM was investigated and found to have no significant influence on the overall tablet physical properties. The compressibility parameter (a) for Cop–CM was calculated from a Kawakita plot and found to be higher (0.661) than that of mannitol (0.576) due to the presence of the highly compressible chitin (0.818). Montelukast sodium and domperidone ODTs produced, using Cop–CM, displayed excellent physicochemical properties. The exceptional binding, fast wetting and superdisintegration properties of Cop–CM, in comparison with commercially available co-processed ODT excipients, results in a unique multifunctional base which can successfully be used in the formulation of oro-dispersible and fast immediate release tablets. PMID:25830680

Template-directed hydrothermal synthesis of hydroxyapatite as a drug delivery system for the poorly water-soluble drug carvedilol

NASA Astrophysics Data System (ADS)

Zhao, Qinfu; Wang, Tianyi; Wang, Jing; Zheng, Li; Jiang, Tongying; Cheng, Gang; Wang, Siling

2011-09-01

In order to improve the dissolution rate and increase the bioavailability of a poorly water-soluble drug, intended to be administered orally, the biocompatible and bioactive mesoporous hydroxyapatite (HA) was successfully synthesized. In the present study, mesoporous HA nanoparticles were produced using Pluronic block co-polymer F127 and cetyltrimethylammonium bromide (CTAB) as templates by the hydrothermal method. The obtained mesoporous HA was employed as a drug delivery carrier to investigate the drug storage/release properties using carvedilol (CAR) as a model drug. Characterizations of the raw CAR powder, mesoporous HA and CAR-loaded HA were carried out by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, N2 adsorption/desorption, thermogravimetric analysis (TGA), and UV-VIS spectrophotometry. The results demonstrated that CAR was successfully incorporated into the mesoporous HA host. In vitro drug release studies showed that mesoporous HA had a high drug load efficiency and provided immediate release of CAR compared with micronized raw drug in simulated gastric fluid (pH 1.2) and intestinal fluid (pH 6.8). Consequently, mesoporous HA is a good candidate as a drug carrier for the oral delivery of poorly water-soluble drugs.

Recrystallization of puerarin using the supercritical fluid antisolvent process

NASA Astrophysics Data System (ADS)

Li, Y.; Yang, D. J.; Zhou, W.; Chen, S. B.; Chen, S. L.

2012-02-01

The purpose of this study was to investigate the influence of supercritical fluid (SCF) processing on the polymorphism of puerarin (Pur), a poorly soluble drug. The gas anti-solvent (GAS) technique was used to crystalize the drug in different conditions. The samples were analyzed by scanning electron microscopy and laser granulometry for changes in the habitus and particle size. The solid state was studied by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and melting point determination. Finally, the dissolution and solubility tests were carried out. It was attested that compared with the commercial Pur in Crystal form I, at the optimum and most of conditions, Pur changed into crystal form II with more orderly and pure appearances. At the concentration of 60 mg/ml and at the solvent of methanol, two other new crystal forms (named form III and form IV) were produced. It was demonstrated that the particles mean diameter, size distribution and morphology can be strongly controlled through the manipulation of the process parameters and more importantly, Pur in the new crystal forms, which were not reported before with better physico-chemical properties could be produced by recrystalization by GAS.

A cryogenic scan mechanism for use in Fourier transform spectrometers

NASA Technical Reports Server (NTRS)

Hakun, Claef F.; Blumenstock, Kenneth A.

1995-01-01

This paper describes the requirements, design, assembly and testing of the linear Scan Mechanism (SM) of the Composite Infrared Spectrometer (CIRS) Instrument. The mechanism consists of an over constrained flexible structure, an innovative moving magnet actuator, passive eddy current dampers, a Differential Eddy Current (DEC) sensor, Optical Limit Sensors (OLS), and a launch lock. Although all the components of the mechanism are discussed, the flexible structure and the magnetic components are the primary focus. Several problems encountered and solutions implemented during the development of the scan mechanism are also described.

Flash Glucose Monitoring: Differences Between Intermittently Scanned and Continuously Stored Data.

PubMed

Pleus, Stefan; Kamecke, Ulrike; Link, Manuela; Haug, Cornelia; Freckmann, Guido

2018-03-01

The flash glucose monitoring system FreeStyle Libre (Abbott Diabetes Care Ltd., Witney, UK) measures interstitial glucose concentrations and continuously stores measurement values every 15 minutes. To obtain a current glucose reading, users have to scan the sensor with the reader. In a clinical trial, 5% of the scanned data showed relative differences of more than ±10% compared with continuously stored data points (median -0.5%). Such differences might impact results of studies using this system. It should be indicated whether scanned or continuously stored data were used for analyses. Health care professionals might have to differentiate between data reports from clinical software and the scanned data their patients are provided with. Additional information on these differences and their potential impact on therapeutic decisions would be helpful.

Quantitative crystallinity determination for E1010, a novel carbapenem antibiotic, using differential scanning calorimetry.

PubMed

Kushida, Ikuo

2012-03-01

The objective of this study was to develop a quantitative crystallinity analysis method for the bulk drug of E1010 ((+)-(4R,5S,6S)-6-[(R)-1-hydroxyethyl]-3-[(2S,4S)-2-[(R)-1-hydroxy-1-[(R)-pyrrolidin-3 -yl]methyl]pyrrolidin-4-yl]thio-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid monohydrochloride), a novel carbapenem antibiotic. X-ray analyses, thermal analyses and hygroscopicity measurements were used to elucidate the crystal structure and the solid state properties. To develop a quantitative method for the crystallinity of E1010 bulk drug, the relationship between enthalpy change obtained by differential scanning calorimetry (DSC) and crystalline form ratio was investigated. E1010 bulk drug was found to exist in a crystalline trihydrate formed in two layers, i.e. a layer of E1010 free form, and a layer consisting of chloride ions and water molecules. The thermal analysis showed an endothermic peak derived from dehydration with the loss of crystal lattices at around 100°C as an onset. The enthalpy change value for the endothermic peak correlated well with crystalline content in binary physical mixtures of the crystalline trihydrate and the amorphous form. In addition, for nine lots of the bulk drug, a positive correlation between the enthalpy change and chemical stability in the solid state was observed. This quantitative analysis of crystallinity using DSC could be applicable for the quality control of the bulk drug to detect variability among manufacturing batches and to estimate the chemical stability of partially amorphous samples. © 2011 The Author. JPP © 2011 Royal Pharmaceutical Society.

Thermal porosity analysis of croscarmellose sodium and sodium starch glycolate by differential scanning calorimetry.

PubMed

Faroongsarng, Damrongsak; Peck, Garnet E

2003-12-30

The aim of the study was to demonstrate the applicability of differential scanning calorimetry (DSC) on porosity analysis for cellulose and starch. Croscarmellose sodium (CCS) and sodium starch glycolate (SSG) were allowed to sorb moisture in 85%, 90%, 95%, and 100% relative humidity (RH) at 40 degrees C for 24 hours. The pretreated samples were then subjected to DSC running temperature ranging from 25 degrees C to -50 degrees C at a cooling rate of 10 degrees C/min. The cooling traces of water crystallization, if present, were transformed to porosity distribution via capillary condensation using Kelvin's equation. The porosity analysis of CCS and SSG was also done using nitrogen adsorption as a reference method. It was found that sorbed water could not be frozen (in cases of 85% and 90% RH) until the moisture content exceeded a cutoff value (in cases of 95% and 100% RH). The nonfreezable moisture content was referred to tightly bound, plasticizing water, whereas the frozen one may be attributed to loosely bound water condensation in pore structure of CCS and SSG surfaces. Not only capillary condensation but also the tightly bound, nonfreezable monolayer water lying along the inner pores of the surface contributed to porosity determination. Good agreement with less than 5% deviation of mean pore size was observed when the results were compared with nitrogen adsorption. The narrower pore size distributions, however, were obtained because of the limitations of the technique. It was concluded that pore analysis by DSC could be successful. Further research needs to be done to account for limitations and to extend the applicability of the technique.

The use of differential scanning fluorimetry in the rational design of plastic antibodies for protein targets.

PubMed

Ashley, Jon; Shukor, Yunus; Tothill, Ibtisam E

2016-11-14

The development of molecularly imprinted polymer nanoparticles (MIP-NPs), which specifically bind biomolecules, is of great interest in the area of biosensors, sample purification, therapeutic agents and biotechnology. Polymerisation techniques such as precipitation polymerisation, solid phase synthesis and core shell surface imprinting have allowed for significant improvements to be made in developing MIP-NPs which specifically recognise proteins. However, the development of MIP-NPs for protein templates (targets) still require lengthy optimisation and characterisation using different ratios of monomers in order to control their size, binding affinity and specificity. In this work we successfully demonstrated that differential scanning fluorimetry (DSF) can be used to rapidly determine the optimum imprinting conditions and monomer composition required for MIP-NP design and polymerisation. This is based on the stability of the protein template and shift in apparent melting points (Tm) upon interaction with different functional acrylic monomers. The method allows for the characterisation of molecularly imprinted nanoparticles (MIP-NPs) due to the observed differences in melting point profiles between, protein-MIP-NPs complexes, pre-polymerisation mixtures and non-imprinted nanoparticles (NIP-NPs) without the need for prior purification. The technique is simple, rapid and can be carried out on most quantitative polymerase chain reaction (qPCR) thermal cyclers which have the required filters for SYPRO © orange and could lead to the rapid development of MIPs nanoparticles for proteins.

L-phenylalanine binding and domain organization in human phenylalanine hydroxylase: a differential scanning calorimetry study.

PubMed

Thórólfsson, Matthías; Ibarra-Molero, Beatriz; Fojan, Peter; Petersen, Steffen B; Sanchez-Ruiz, Jose M; Martínez, Aurora

2002-06-18

Human phenylalanine hydroxylase (hPAH) is a tetrameric enzyme that catalyzes the hydroxylation of L-phenylalanine (L-Phe) to L-tyrosine; a dysfunction of this enzyme causes phenylketonuria. Each subunit in hPAH contains an N-terminal regulatory domain (Ser2-Ser110), a catalytic domain (Asp112-Arg410), and an oligomerization domain (Ser411-Lys452) including dimerization and tetramerization motifs. Two partially overlapping transitions are seen in differential scanning calorimetry (DSC) thermograms for wild-type hPAH in 0.1 M Na-Hepes buffer, 0.1 M NaCl, pH 7.0. Although these transitions are irreversible, studies on their scan-rate dependence support that the equilibrium thermodynamics analysis is permissible in this case. Comparison with the DSC thermograms for truncated forms of the enzyme, studies on the protein and L-Phe concentration effects on the transitions, and structure-energetic calculations based on a modeled structure support that the thermal denaturation of hPAH occurs in three stages: (i) unfolding of the four regulatory domains, which is responsible for the low-temperature calorimetric transition; (ii) unfolding of two (out of the four) catalytic domains, which is responsible for the high-temperature transition; and (iii) irreversible protein denaturation, which is likely responsible for the observed exothermic distortion in the high-temperature side of the high-temperature transition. Stages 1 and 2 do not appear to be two-state processes. We present an approach to the analysis of ligand effects on DSC transition temperatures, which is based on the general binding polynomial formalism and is not restricted to two-state transitions. Application of this approach to the L-Phe effect on the DSC thermograms for hPAH suggests that (i) there are no binding sites for L-Phe in the regulatory domains; therefore, contrary to the common belief, the activation of PAH by L-Phe seems to be the result of its homotropic cooperative binding to the active sites. (ii

Bone scans after total knee arthroplasty in asymptomatic patients. Cemented versus cementless

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofmann, A.A.; Wyatt, R.W.; Daniels, A.U.

1990-02-01

The natural history of bone scans after total knee arthroplasty (TKA) was studied in 26 patients with 28 cemented TKAs and 29 patients with 31 cementless TKAs. The bone scans were examined at specified postoperative intervals. Radionuclide activity of the femoral, tibial, and patellar regions was measured. Six patients who developed pain postoperatively were excluded. Bone scans immediately postoperative and at three months demonstrated increased uptake, which gradually decreased to baseline levels at ten to 12 months. Radioisotope uptake was comparable in the cemented and cementless groups, but was highly variable in individual patients and in each of the follow-upmore » periods. A single postoperative bone scan cannot differentiate component loosening from early bone remodeling. Sequential bone scans, as a supplement to the clinical examination and conventional radiography, may prove useful in the diagnosis of TKA failure.« less

Miscibility, Crystallization, and Rheological Behavior of Solution Casting Poly(3-hydroxybutyrate)/poly(ethylene succinate) Blends Probed by Differential Scanning Calorimetry, Rheology, and Optical Microscope Techniques

NASA Astrophysics Data System (ADS)

Sun, Wei-hua; Qiao, Xiao-ping; Cao, Qi-kun; Liu, Jie-ping

2010-02-01

The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybutyrate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry, rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. It was found that the PHB and PES can crystallize simultaneously or upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The influence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed.

Dynamic scan control in STEM: Spiral scans

DOE PAGES

Lupini, Andrew R.; Borisevich, Albina Y.; Kalinin, Sergei V.; ...

2016-06-13

Here, scanning transmission electron microscopy (STEM) has emerged as one of the foremost techniques to analyze materials at atomic resolution. However, two practical difficulties inherent to STEM imaging are: radiation damage imparted by the electron beam, which can potentially damage or otherwise modify the specimen and slow-scan image acquisition, which limits the ability to capture dynamic changes at high temporal resolution. Furthermore, due in part to scan flyback corrections, typical raster scan methods result in an uneven distribution of dose across the scanned area. A method to allow extremely fast scanning with a uniform residence time would enable imaging atmore » low electron doses, ameliorating radiation damage and at the same time permitting image acquisition at higher frame-rates while maintaining atomic resolution. The practical complication is that rastering the STEM probe at higher speeds causes significant image distortions. Non-square scan patterns provide a solution to this dilemma and can be tailored for low dose imaging conditions. Here, we develop a method for imaging with alternative scan patterns and investigate their performance at very high scan speeds. A general analysis for spiral scanning is presented here for the following spiral scan functions: Archimedean, Fermat, and constant linear velocity spirals, which were tested for STEM imaging. The quality of spiral scan STEM images is generally comparable with STEM images from conventional raster scans, and the dose uniformity can be improved.« less

Dynamic scan control in STEM: Spiral scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lupini, Andrew R.; Borisevich, Albina Y.; Kalinin, Sergei V.

Here, scanning transmission electron microscopy (STEM) has emerged as one of the foremost techniques to analyze materials at atomic resolution. However, two practical difficulties inherent to STEM imaging are: radiation damage imparted by the electron beam, which can potentially damage or otherwise modify the specimen and slow-scan image acquisition, which limits the ability to capture dynamic changes at high temporal resolution. Furthermore, due in part to scan flyback corrections, typical raster scan methods result in an uneven distribution of dose across the scanned area. A method to allow extremely fast scanning with a uniform residence time would enable imaging atmore » low electron doses, ameliorating radiation damage and at the same time permitting image acquisition at higher frame-rates while maintaining atomic resolution. The practical complication is that rastering the STEM probe at higher speeds causes significant image distortions. Non-square scan patterns provide a solution to this dilemma and can be tailored for low dose imaging conditions. Here, we develop a method for imaging with alternative scan patterns and investigate their performance at very high scan speeds. A general analysis for spiral scanning is presented here for the following spiral scan functions: Archimedean, Fermat, and constant linear velocity spirals, which were tested for STEM imaging. The quality of spiral scan STEM images is generally comparable with STEM images from conventional raster scans, and the dose uniformity can be improved.« less

Glass transition of anhydrous starch by fast scanning calorimetry.

PubMed

Monnier, Xavier; Maigret, Jean-Eudes; Lourdin, Denis; Saiter, Allisson

2017-10-01

By means of fast scanning calorimetry, the glass transition of anhydrous amorphous starch has been measured. With a scanning rate of 2000Ks -1 , thermal degradation of starch prior to the glass transition has been inhibited. To certify the glass transition measurement, structural relaxation of the glassy state has been investigated through physical aging as well as the concept of limiting fictive temperature. In both cases, characteristic enthalpy recovery peaks related to the structural relaxation of the glass have been observed. Thermal lag corrections based on the comparison of glass transition temperatures measured by means of differential and fast scanning calorimetry have been proposed. The complementary investigations give an anhydrous amorphous starch glass transition temperature of 312±7°C. This estimation correlates with previous extrapolation performed on hydrated starches. Copyright © 2017 Elsevier Ltd. All rights reserved.

A prospective study of radionuclide biliary scanning in acute pancreatitis.

PubMed Central

Neoptolemos, J. P.; Fossard, D. P.; Berry, J. M.

1983-01-01

Early surgery for biliary pancreatitis has resulted in a need for an accurate method of gallstone detection in acute pancreatitis. Fifty patients with acute pancreatitis were studied prospectively to assess the diagnostic value of Radionuclide Biliary Scanning (RBS) performed within 72 hours of an attack. To assess the general accuracy of RBS a further 154 patients with suspected acute cholecystitis or biliary colic were similarly studied. There were 34 patients with biliary pancreatitis and 18 (53%) had a positive scan (no gallbladder seen). There were 16 patients with non-biliary pancreatitis and 5 (31%) had a positive scan. All 51 patients with acute cholecystitis had a positive scan, as did 82% of the 51 patients with biliary colic. There were 52 patients with no biliary or pancreatic disease and none of these had a positive scan. RBS is highly accurate in confirming a diagnosis of acute cholecystitis or biliary colic. However, it cannot be relied on to differentiate between biliary and non-biliary pancreatitis and should certainly not be used as the basis for biliary surgery in these patients. PMID:6859781

Hyper-spectrum scanning laser optical tomography

NASA Astrophysics Data System (ADS)

Chen, Lingling; Li, Guiye; Li, Yingchao; Liu, Lina; Liu, Ang; Hu, Xuejuan; Ruan, Shuangchen

2018-02-01

We describe a quantitative fluorescence projection tomography technique which measures the three-dimensional fluorescence spectrum in biomedical samples with size up to several millimeters. This is achieved by acquiring a series of hyperspectral images, by using laser scanning scheme, at different projection angles. We demonstrate that this technique provide a quantitative measure of the fluorescence signal by comparing the spectrum and intensity profile of a fluorescent bead phantom and also demonstrate its application to differentiating the extrinsic label and the autofluorescence in a mouse embryo.

Interior reconstruction method based on rotation-translation scanning model.

PubMed

Wang, Xianchao; Tang, Ziyue; Yan, Bin; Li, Lei; Bao, Shanglian

2014-01-01

In various applications of computed tomography (CT), it is common that the reconstructed object is over the field of view (FOV) or we may intend to sue a FOV which only covers the region of interest (ROI) for the sake of reducing radiation dose. These kinds of imaging situations often lead to interior reconstruction problems which are difficult cases in the reconstruction field of CT, due to the truncated projection data at every view angle. In this paper, an interior reconstruction method is developed based on a rotation-translation (RT) scanning model. The method is implemented by first scanning the reconstructed region, and then scanning a small region outside the support of the reconstructed object after translating the rotation centre. The differentiated backprojection (DBP) images of the reconstruction region and the small region outside the object can be respectively obtained from the two-time scanning data without data rebinning process. At last, the projection onto convex sets (POCS) algorithm is applied to reconstruct the interior region. Numerical simulations are conducted to validate the proposed reconstruction method.

Immobilization of kojic acid in ZnAl-hydrotalcite like compounds

NASA Astrophysics Data System (ADS)

Ambrogi, Valeria; Perioli, Luana; Nocchetti, Morena; Latterini, Loredana; Pagano, Cinzia; Massetti, Elena; Rossi, Carlo

2012-01-01

Kojic acid (KOJ) is a melanin synthesis inhibitor widely used as skin lightening agent in topical preparations. Unfortunately it is easily susceptible to photo-oxidation, phenomenon responsible for chemical and organoleptic modifications. The aim of this work was the intercalation of KOJ in hydrotalcite-like compounds (HTlc) in order to stabilize KOJ and to reduce its photolability. Hydrotalcite containing Zn and Al (ZnAl-HTlc) was used as host to obtain the final compound ZnAl-HTlc-KOJ. The intercalation was carried out, after many attempts, by ionic exchange mechanism by means of the strong base EtO- in anhydrous ethanol/dimethylsulfoxide (DMSO) mixture as solvent in order to generate KOJ- anions. The final product was characterized by the X-ray powder diffraction (XRPD), FT-IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis. The intercalated compound was formulated in a siliconic water free self-emulsifying ointment and the in vitro release profile was evaluated. All samples (intercalation compound and its formulation) were submitted also to spectrophotometric assays in order to evaluate the matrix protective effect towards ultraviolet rays.

Characterization of naproxen-loaded solid SMEDDSs prepared by spray drying: the effect of the polysaccharide carrier and naproxen concentration.

PubMed

Čerpnjak, Katja; Zvonar, Alenka; Vrečer, Franc; Gašperlin, Mirjana

2015-05-15

The purpose of this study was to prepare solid SMEDDS (sSMEDDS) particles produced by spray-drying using maltodextrin (MD), hypromellose (HPMC), and a combination of the two as a solid carrier. Naproxen (NPX) as the model drug was dissolved (at 6% concentration) or partially suspended (at 18% concentration) in a liquid SMEDDS composed of Miglyol(®) 812, Peceol™, Gelucire(®) 44/14, and Solutol(®) HS 15. Among the sSMEDDSs tested, the MD-based sSMEDDSs (with a granular, smooth-surfaced, microspherical appearance) preserved the self-microemulsifying properties of liquid SMEDDSs and exhibited dissolution profiles similar to those of liquid SMEDDSs, irrespective of the concentration of NPX. In contrast, HPMC-based sSMEDDSs (irregular-shaped microparticles) exhibited slightly prolonged release times due to the polymeric nature of the carrier. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and Raman mapping analysis confirmed molecularly dissolved NPX (at 6% of drug loading), whereas at 18% NPX loading drug is partially molecularly dissolved and partially in the crystalline state. Copyright © 2015. Published by Elsevier B.V.

Fabrication and evaluation of nanoparticle-assembled BSA microparticles for enhanced liver delivery of glycyrrhetinic acid.

PubMed

Wang, Wenping; Lei, Yaya; Sui, Hong; Zhang, Wenping; Zhu, Rongyue; Feng, Jun; Wang, Hong

2017-06-01

The aim of the present study was to prepare and evaluate microparticle formulation encapsulated with glycyrrhetinic acid (GA) based on bovine serum albumin (BSA). The drug-loaded nanoparticles were firstly formed by a simple desolvation method, and were further assembled into microparticles using zinc chloride and glutaraldehyde as crosslinkers. The obtained microparticles contained approximately 30% (w/w) drug and showed as spherical particles with a size of about 2 μm. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) analysis indicated that GA lost its crystallinity during the nano/microencapsulation process. In vitro dissolution study demonstrated a typical sustained-release pattern for 24 h with a burst of 28.1% at the first 30 min, which fitted well by Higuchi model. After intravenous administration into mice, the microparticle formulation remained a higher drug level than the solution formulation in blood and liver for more than 18 h. These results suggested the potential benefit of using the prepared albumin microparticles as a promising vector for enhanced liver delivery of poorly water-soluble drug.

Development of quercetin-phospholipid complex to improve the bioavailability and protection effects against carbon tetrachloride-induced hepatotoxicity in SD rats.

PubMed

Zhang, Kexia; Zhang, Meiyu; Liu, Ziying; Zhang, Yuanyuan; Gu, Liqiang; Hu, Gaosheng; Chen, Xiaohui; Jia, Jingming

2016-09-01

Quercetin (QT) is a natural flavonoid with various biological activities and pharmacological actions. However, the bioavailability of QT is relatively low due to its low solubility which severely limits its use. In this study, we intended to improve the bioavailability of QT by preparing quercetin-phospholipid complex (QT-PC) and investigate the protective effect of QT-PC against carbon tetrachloride (CCl4) induced acute liver damage in Sprague-Dawley (SD) rats. The physicochemical properties of QT-PC were characterized in terms of infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (XRPD) and water/n-octanol solubility. FTIR, DSC and XRPD data confirmed the formation of QT-PC. The water solubility of QT was improved significantly in the prepared complex, indicating its increased hydrophilicity. Oral bioavailability of QT and QT-PC was evaluated in SD rats, and the plasma QT was estimated by HPLC-MS. QT-PC exhibited higher Cmax (1.58±0.11 vs. 0.67±0.08μg/mL), increased AUC0-∞ (8.60±1.25 vs. 2.41±0.51mg/Lh) and t1/2z (7.76±1.09 vs. 4.81±0.87h) when compared to free QT. The greater absorption of QT-PC group suggested the improved bioavailability. Moreover, biochemical changes and histopathological observations revealed that QT-PC provided better protection to rat liver than free QT at the same dose. Thus, phospholipid complexation might be one of the suitable approaches to improve the oral bioavailability of QT and obtain better protective effects against CCl4 induced acute liver damage in SD rats than free QT at the same dose level. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of extended-release patient-tailored prednisolone tablets via fused deposition modelling (FDM) 3D printing.

PubMed

Skowyra, Justyna; Pietrzak, Katarzyna; Alhnan, Mohamed A

2015-02-20

Rapid and reliable tailoring of the dose of controlled release tablets to suit an individual patient is a major challenge for personalized medicine. The aim of this work was to investigate the feasibility of using a fused deposition modelling (FDM) based 3D printer to fabricate extended release tablet using prednisolone loaded poly(vinyl alcohol) (PVA) filaments and to control its dose. Prednisolone was loaded into a PVA-based (1.75 mm) filament at approximately 1.9% w/w via incubation in a saturated methanolic solution of prednisolone. The physical form of the drug was assessed using differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). Dose accuracy and in vitro drug release patterns were assessed using HPLC and pH change flow-through dissolution test. Prednisolone loaded PVA filament demonstrated an ability to be fabricated into regular ellipse-shaped solid tablets using the FDM-based 3D printer. It was possible to control the mass of printed tablet through manipulating the volume of the design (R(2) = 0.9983). On printing tablets with target drug contents of 2, 3, 4, 5, 7.5 and 10mg, a good correlation between target and achieved dose was obtained (R(2) = 0.9904) with a dose accuracy range of 88.7-107%. Thermal analysis and XRPD indicated that the majority of prednisolone existed in amorphous form within the tablets. In vitro drug release from 3D printed tablets was extended up to 24h. FDM based 3D printing is a promising method to produce and control the dose of extended release tablets, providing a highly adjustable, affordable, minimally sized, digitally controlled platform for producing patient-tailored medicines. Copyright © 2015. Published by Elsevier B.V.

SCAN+

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenneth Krebs, John Svoboda

2009-11-01

SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing formore » automatic unattended cask scanning that may take several hours.« less

Shape Memory Alloys for Monitoring Minor Over-Heating/Cooling Based on the Temperature Memory Effect via Differential Scanning Calorimetry: A Review of Recent Progress

NASA Astrophysics Data System (ADS)

Wang, T. X.; Huang, W. M.

2017-12-01

The recent development in the temperature memory effect (TME) via differential scanning calorimetry in shape memory alloys is briefly discussed. This phenomenon was also called the thermal arrest memory effect in the literature. However, these names do not explicitly reveal the potential application of this phenomenon in temperature monitoring. On the other hand, the standard testing process of the TME has great limitation. Hence, it cannot be directly applied for temperature monitoring in most of the real engineering applications in which temperature fluctuation occurs mostly in a random manner within a certain range. However, as shown here, after proper modification, we are able to monitor the maximum or minimum temperature in either over-heating or over-cooling with reasonable accuracy.

Characteristics of rose hip (Rosa canina L.) cold-pressed oil and its oxidative stability studied by the differential scanning calorimetry method.

PubMed

Grajzer, Magdalena; Prescha, Anna; Korzonek, Katarzyna; Wojakowska, Anna; Dziadas, Mariusz; Kulma, Anna; Grajeta, Halina

2015-12-01

Two new commercially available high linolenic oils, pressed at low temperature from rose hip seeds, were characterised for their composition, quality and DPPH radical scavenging activity. The oxidative stability of oils was assessed using differential scanning calorimetry (DSC). Phytosterols, tocopherols and carotenoids contents were up to 6485.4; 1124.7; and 107.7 mg/kg, respectively. Phenolic compounds determined for the first time in rose hip oil totalled up to 783.55 μg/kg, with a predominant presence of p-coumaric acid methyl ester. Antiradical activity of the oils reached up to 3.00 mM/kg TEAC. The acid, peroxide and p-anisidine values as well as iron and copper contents indicated good quality of the oils. Relatively high protection against oxidative stress in the oils seemed to be a result of their high antioxidant capacity and the level of unsaturation of fatty acids. Copyright © 2015 Elsevier Ltd. All rights reserved.

[F-18-fluordeoxyglucose positron emission tomography on patients with differentiated thyroid cancer who present elevated human serum thyroglobulin levels and negative I-131 whole body scan].

PubMed

Ruiz Franco-Baux, J V; Borrego Dorado, I; Gómez Camarero, P; Rodríguez Rodríguez, J R; Vázquez Albertino, R J; Navarro González, E; Astorga Jiménez, R

2005-01-01

This study aimed to evaluate the role of Fluorine-18-fluorodeoxyglucose positron emission tomography (PET-FDG) in patients with elevated serum thyroglobulin (hTg) levels where thyroid cancer tissue does not concentrate radioiodine, rendering false-negative results on I-131 scanning. Whole-body PET imaging using FDG was performed in 54 patients (37 female, 17 male) aged 17-88 years: 45 with papillary tumors and 9 with follicular tumors who were suspected of having recurrent thyroid carcinoma due to elevated thyroglobulin levels (hTg > 2 ng/ml) under thyroid-stimulating hormone (TSH > or = 30 microIU/ml) in whom the iodine scan was negative. All whole body scans were obtained with diagnostic doses (185 MBq). Whole body PET imaging was performed in fasting patients following i.v. administration of 370 MBq FDG while the patients were receiving full thyroid hormone replacement. Before PET, 99mTc methoxyisobutylisonitrile scintigraphy (99mTc-MIBI) was done in 14 patients and morphologic imaging in 26 by CT scan. Positive PET results confirmed the presence of hypermetabolic foci in 25/54 patients (46.29 %). Positive findings were found for PET-FDG in patients with hTg levels higher than 10 ng/ml receiving full thyroid hormone replacement. 99mTc-MIBI demonstrated lesions in 7/14 patients (50 %). PET-FDG and 99mTc-MIBI had congruent positive results in 4/7 patients. All the lesions found by CT were detected by PET-FDG, while recurrent disease was found in 12/21 patients with previous negative CT. These results suggest that PET-FDG seems to be a promising tool in the follow-up of thyroid cancer and should be considered in patients suffering from differentiated thyroid cancer with suspected recurrence and/or metastases by elevated thyroglobulin levels, and negative I-131 whole body scans. PET-FDG might be more useful at hTg levels > 10 ng/ml.

X-ray phase scanning setup for non-destructive testing using Talbot-Lau interferometer

NASA Astrophysics Data System (ADS)

Bachche, S.; Nonoguchi, M.; Kato, K.; Kageyama, M.; Koike, T.; Kuribayashi, M.; Momose, A.

2016-09-01

X-ray grating interferometry has a great potential for X-ray phase imaging over conventional X-ray absorption imaging which does not provide significant contrast for weakly absorbing objects and soft biological tissues. X-ray Talbot and Talbot-Lau interferometers which are composed of transmission gratings and measure the differential X-ray phase shifts have gained popularity because they operate with polychromatic beams. In X-ray radiography, especially for nondestructive testing in industrial applications, the feasibility of continuous sample scanning is not yet completely revealed. A scanning setup is frequently advantageous when compared to a direct 2D static image acquisition in terms of field of view, exposure time, illuminating radiation, etc. This paper demonstrates an efficient scanning setup for grating-based Xray phase imaging using laboratory-based X-ray source. An apparatus consisting of an X-ray source that emits X-rays vertically, optical gratings and a photon-counting detector was used with which continuously moving objects across the field of view as that of conveyor belt system can be imaged. The imaging performance of phase scanner was tested by scanning a long continuous moving sample at a speed of 5 mm/s and absorption, differential-phase and visibility images were generated by processing non-uniform moire movie with our specially designed phase measurement algorithm. A brief discussion on the feasibility of phase scanner with scanning setup approach including X-ray phase imaging performance is reported. The successful results suggest a breakthrough for scanning objects those are moving continuously on conveyor belt system non-destructively using the scheme of X-ray phase imaging.

Raman scattering boson peak and differential scanning calorimetry studies of the glass transition in tellurium-zinc oxide glasses.

PubMed

Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S

2010-05-19

Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO(2))(1 - x)(ZnO)(x) (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T(g) has been determined for each glass, showing a monotonous decrease of T(g) with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T(d) very close to the respective T(g) values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T(g) in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T(g) and confirms the correlation between the BP and the MRO of glasses.

Mathematics in Physics Education: Scanning Historical Evolution of the Differential to Find a More Appropriate Model for Teaching Differential Calculus in Physics

ERIC Educational Resources Information Center

Martinez-Torregrosa, Joaquin; Lopez-Gay, Rafael; Gras-Marti, Albert

2006-01-01

Despite its frequent use, there is little understanding of the concept of differential among upper high school and undergraduate students of physics. As a first step to identify the origin of this situation and to revert it, we have done a historic and epistemological study aimed at clarifying the role and the meaning of the differential in…

Structural domains and conformational changes in nuclear chromatin: a quantitative thermodynamic approach by differential scanning calorimetry.

PubMed

Balbi, C; Abelmoschi, M L; Gogioso, L; Parodi, S; Barboro, P; Cavazza, B; Patrone, E

1989-04-18

A good deal of information on the thermodynamic properties of chromatin was derived in the last few years from optical melting experiments. The structural domains of the polynucleosomal chain, the linker, and the core particle denature as independent units. The differential scanning calorimetry profile of isolated chromatin is made up of three endotherms, at approximately 74, 90, and 107 degrees C, having an almost Gaussian shape. Previous work on this matter, however, was mainly concerned with the dependence of the transition enthalpy on external parameters, such as the ionic strength, or with the melting of nuclei from different sources. In this paper we report the structural assignment of the transitions of rat liver nuclei, observed at 58, 66, 75, 92, and 107 degrees C. They are representative of the quiescent state of the cell. The strategy adopted in this work builds on the method developed for the investigation of complex biological macromolecules. The heat absorption profile of the nucleus was related to the denaturation of isolated nuclear components; electron microscopy and electrophoretic techniques were used for their morphological and molecular characterization. The digestion of chromatin by endogenous nuclease mimics perfectly the decondensation of the higher order structure and represented the source of several misinterpretations. This point was carefully examined in order to define unambiguously the thermal profile of native nuclei. The low-temperature transitions, centered around 58 and 66 degrees C, arise from the melting of scaffolding structures and of the proteins associated with heterogeneous nuclear RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of differential scanning calorimetry to detect canola oil (Brassica napus L.) adulterated with lard stearin.

PubMed

Marikkar, Jalaldeen Mohammed Nazrim; Rana, Sohel

2014-01-01

A study was conducted to detect and quantify lard stearin (LS) content in canola oil (CaO) using differential scanning calorimetry (DSC). Authentic samples of CaO were obtained from a reliable supplier and the adulterant LS were obtained through a fractional crystallization procedure as reported previously. Pure CaO samples spiked with LS in levels ranging from 5 to 15% (w/w) were analyzed using DSC to obtain their cooling and heating profiles. The results showed that samples contaminated with LS at 5% (w/w) level can be detected using characteristic contaminant peaks appearing in the higher temperature regions (0 to 70°C) of the cooling and heating curves. Pearson correlation analysis of LS content against individual DSC parameters of the adulterant peak namely peak temperature, peak area, peak onset temperature indicated that there were strong correlations between these with the LS content of the CaO admixtures. When these three parameters were engaged as variables in the execution of the stepwise regression procedure, predictive models for determination of LS content in CaO were obtained. The predictive models obtained with single DSC parameter had relatively lower coefficient of determination (R(2) value) and higher standard error than the models obtained using two DSC parameters in combination. This study concluded that the predictive models obtained with peak area and peak onset temperature of the adulteration peak would be more accurate for prediction of LS content in CaO based on the highest coefficient of determination (R(2) value) and smallest standard error.

pH-dependent Differential Scanning Calorimetry and Dynamic Light Scattering Studies of 21:0 PC and 18:0 PS Lipid Binary System

NASA Astrophysics Data System (ADS)

Ali, Rejwan

2010-03-01

Large unilamallar vesicle has been a model system to study many membrane functions. High Tg lipid systems offer many potential biomedical applications in lipid-based delivery applications. While the optimized vesicle functionalities are achieved by Polyethylene Glycol (PEG) polymer, modified PEG and other functional molecule incorporation, however, the host binary lipid system plays the pivotal role in pH-dependent phase transition based lipid vehicular methods. We have investigated a lipid binary system composed of 21:0 PC (1,2-dihenarachidoyl-sn-glycero-3-phosphocholine) and 18:0 PS(1,2-distearoyl-sn-glycero-3-phospho-L-serine). Preliminary studies implementing differential scanning calorimetry shows pH plays key role in temperature shift and thermotropic phase behavior of the binary system. While dynamic light scattering study shows lipid vesicle size is almost independent of pH changes. We will also present pH-dependent thermodynamic parameters to correlate underlying molecular mechanism in relevant pH-range.

Optical methods and differential scanning calorimetry as a potential tool for discrimination of olive oils (extra virgin and mix with vegetable oils)

NASA Astrophysics Data System (ADS)

Nikolova, Kr.; Yovcheva, T.; Marudova, M.; Eftimov, T.; Bodurov, I.; Viraneva, A.; Vlaeva, I.

2016-03-01

Eleven samples from olive oil have been investigated using four physical methods - refractive index measurement, fluorescence spectra, color parameters and differential scanning colorimetry. In pomace olive oil (POO) and extra virgin olive oil (EVOO) the oleic acid (65.24 %-78.40 %) predominates over palmitic (10.47 %-15.07 %) and linoleic (5.26 %-13.92 %) acids. The fluorescence spectra contain three peaks related to oxidation products at about λ = (500-540) nm, chlorophyll content at about λ = (675-680) nm and non determined pigments at λ = (700-750) nm. The melting point for EVOO and POO is between -1 °C and -6 °C. In contrast, the salad olive oils melt between -24 °C and -30 °C. The refractive index for EVOO is lower than that for mixed olive oils. The proposed physical methods could be used for fast and simple detection of vegetable oils in EVOO without use of chemical substances. The experimental results are in accordance with those obtained by chemical analysis.

Supercritical fluid crystallization of griseofulvin: crystal habit modification with a selective growth inhibitor.

PubMed

Jarmer, Daniel J; Lengsfeld, Corinne S; Anseth, Kristi S; Randolph, Theodore W

2005-12-01

Poly (sebacic anhydride) (PSA) was used as a growth inhibitor to selectively modify habit of griseofulvin crystals formed via the Precipitation with a compressed-fluid antisolvent (PCA) process. PSA and griseofulvin were coprecipitated within a PCA injector, which provided efficient mixing between the solution and compressed antisolvent process streams. Griseofulvin crystal habit was modified from acicular to bipyramidal when the mass ratio of PSA/griseofulvin in the solution feed stream was Scanning electron microscopy (SEM) was used to characterize the griseofulvin and PSA particles, and gave results consistent with a selective growth inhibition mechanism. SEM micrographs showed regions on griseofulvin crystals where PSA microparticles had preferentially adsorbed. X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) analysis of the griseofulvin crystals indicated no changes in the crystalline form after the habit modification. Powder compressibility decreased from 49 +/- 3% to 28 +/- 7% with the modification in crystal habit. No change in the physical stability of the processed powder was observed after being stored at 25 degrees C/60% RH and 40 degrees C/70% RH for 23 days. Despite the change in crystal habit, griseofulvin crystals achieved 100% dissolution within 60 min in a simulated gastric fluid. (c) 2005 Wiley-Liss, Inc.

Effect of Extraction Method on the Oxidative Stability of Camelina Seed Oil Studied by Differential Scanning Calorimetry.

PubMed

Belayneh, Henok D; Wehling, Randy L; Cahoon, Edgar B; Ciftci, Ozan N

2017-03-01

Camelina seed is a new alternative omega-3 source attracting growing interest. However, it is susceptible to oxidation due to its high omega-3 content. The objective of this study was to improve the oxidative stability of the camelina seed oil at the extraction stage in order to eliminate or minimize the use of additive antioxidants. Camelina seed oil extracts were enriched in terms of natural antioxidants using ethanol-modified supercritical carbon dioxide (SC-CO 2 ) extraction. Oxidative stability of the camelina seed oils extracted by ethanol modified SC-CO 2 was studied by differential scanning calorimeter (DSC), and compared with cold press, hexane, and SC-CO 2 methods. Nonisothermal oxidation kinetics of the oils obtained by different extraction methods were studied by DSC at varying heating rates (2.5, 5, 10, and 15 °C/min). Increasing ethanol level in the ethanol-modified SC-CO 2 increased the oxidative stability. Based on oxidation onset temperatures (T on ), SC-CO 2 containing 10% ethanol yielded the most stable oil. Oxidative stability depended on the type and content of the polar fractions, namely, phenolic compounds and phospholipids. Phenolic compounds acted as natural antioxidants, whereas increased phospholipid contents decreased the stability. Study has shown that the oxidative stability of the oils can be improved at the extraction stage and this may eliminate the need for additive antioxidants. © 2017 Institute of Food Technologists®.

Femtosecond Z-scan measurements of the nonlinear refractive index of fused silica

NASA Astrophysics Data System (ADS)

Zhang, Lin; Shi, Zhendong; Ma, Hua; Ren, Huan; Yuan, Quan; Ma, Yurong; Feng, Xiaoxuan; Chen, Bo; Yang, Yi

2018-01-01

Z-scan technology is a popular experimental technique for determining the nonlinear refractive index of the material. However, it encounters a great difficulty in measuring the weak nonlinear material like fused silica which is about two orders of magnitude below the nonlinear refractive index of most of the materials studied with the nanosecond and picosecond Z-scan methods. In this case, the change of refractive index introduced by accumulation of thermal effects cannot be neglected. In order to have a reliable measurement of the nonlinear refractive index, a metrology bench based on the femtosecond Z-scan technology is developed. The intensity modulation component and the differential measurement system are applied to guarantee the accuracy of the measuring system. Based on the femtosecond Z-scan theory, the femtosecond laser Z-scan technique is performed on fused silica, and the nonlinear refractive index of Fused silica is determined to be 9.2039×10-14esu for 800nm, 37fs pulse duration at I0=50GW/cm2 with a good repeatability of 6.7%.

Visual scanning behavior is related to recognition performance for own- and other-age faces

PubMed Central

Proietti, Valentina; Macchi Cassia, Viola; dell’Amore, Francesca; Conte, Stefania; Bricolo, Emanuela

2015-01-01

It is well-established that our recognition ability is enhanced for faces belonging to familiar categories, such as own-race faces and own-age faces. Recent evidence suggests that, for race, the recognition bias is also accompanied by different visual scanning strategies for own- compared to other-race faces. Here, we tested the hypothesis that these differences in visual scanning patterns extend also to the comparison between own and other-age faces and contribute to the own-age recognition advantage. Participants (young adults with limited experience with infants) were tested in an old/new recognition memory task where they encoded and subsequently recognized a series of adult and infant faces while their eye movements were recorded. Consistent with findings on the other-race bias, we found evidence of an own-age bias in recognition which was accompanied by differential scanning patterns, and consequently differential encoding strategies, for own-compared to other-age faces. Gaze patterns for own-age faces involved a more dynamic sampling of the internal features and longer viewing time on the eye region compared to the other regions of the face. This latter strategy was extensively employed during learning (vs. recognition) and was positively correlated to discriminability. These results suggest that deeply encoding the eye region is functional for recognition and that the own-age bias is evident not only in differential recognition performance, but also in the employment of different sampling strategies found to be effective for accurate recognition. PMID:26579056

Differentiating Stress Fracture From Periostitis.

PubMed

Martire, J R

1994-10-01

In brief Even in the age of high-technology MRI and CT, the triple-phase bone scan (TPBS) remains an exceptionally useful and accurate tool in evaluating athletic injuries. This is perhaps best seen in active people with overuse injuries of the tibia, femur, or humerus when plain films are negative but bone pain persists. Differentiating periostitis from stress fracture requires analyzing distinctive TPBS appearances and patterns.

Fast scanning mode and its realization in a scanning acoustic microscope

NASA Astrophysics Data System (ADS)

Ju, Bing-Feng; Bai, Xiaolong; Chen, Jian

2012-03-01

The scanning speed of the two-dimensional stage dominates the efficiency of mechanical scanning measurement systems. This paper focused on a detailed scanning time analysis of conventional raster and spiral scan modes and then proposed two fast alternative scanning modes. Performed on a self-developed scanning acoustic microscope (SAM), the measured images obtained by using the conventional scan mode and fast scan modes are compared. The total scanning time is reduced by 29% of the two proposed fast scan modes. It will offer a better solution for high speed scanning without sacrificing the system stability, and will not introduce additional difficulties to the configuration of scanning measurement systems. They can be easily applied to the mechanical scanning measuring systems with different driving actuators such as piezoelectric, linear motor, dc motor, and so on. The proposed fast raster and square spiral scan modes are realized in SAM, but not specially designed for it. Therefore, they have universal adaptability and can be applied to other scanning measurement systems with two-dimensional mechanical scanning stages, such as atomic force microscope or scanning tunneling microscope.

Technical Considerations on Scanning and Image Analysis for Amyloid PET in Dementia.

PubMed

Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Yamamoto, Yasuji; Senda, Michio

2017-01-01

Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice.

Explicit Filtering Based Low-Dose Differential Phase Reconstruction Algorithm with the Grating Interferometry.

PubMed

Jiang, Xiaolei; Zhang, Li; Zhang, Ran; Yin, Hongxia; Wang, Zhenchang

2015-01-01

X-ray grating interferometry offers a novel framework for the study of weakly absorbing samples. Three kinds of information, that is, the attenuation, differential phase contrast (DPC), and dark-field images, can be obtained after a single scanning, providing additional and complementary information to the conventional attenuation image. Phase shifts of X-rays are measured by the DPC method; hence, DPC-CT reconstructs refraction indexes rather than attenuation coefficients. In this work, we propose an explicit filtering based low-dose differential phase reconstruction algorithm, which enables reconstruction from reduced scanning without artifacts. The algorithm adopts a differential algebraic reconstruction technique (DART) with the explicit filtering based sparse regularization rather than the commonly used total variation (TV) method. Both the numerical simulation and the biological sample experiment demonstrate the feasibility of the proposed algorithm.

Explicit Filtering Based Low-Dose Differential Phase Reconstruction Algorithm with the Grating Interferometry

PubMed Central

Zhang, Li; Zhang, Ran; Yin, Hongxia; Wang, Zhenchang

2015-01-01

X-ray grating interferometry offers a novel framework for the study of weakly absorbing samples. Three kinds of information, that is, the attenuation, differential phase contrast (DPC), and dark-field images, can be obtained after a single scanning, providing additional and complementary information to the conventional attenuation image. Phase shifts of X-rays are measured by the DPC method; hence, DPC-CT reconstructs refraction indexes rather than attenuation coefficients. In this work, we propose an explicit filtering based low-dose differential phase reconstruction algorithm, which enables reconstruction from reduced scanning without artifacts. The algorithm adopts a differential algebraic reconstruction technique (DART) with the explicit filtering based sparse regularization rather than the commonly used total variation (TV) method. Both the numerical simulation and the biological sample experiment demonstrate the feasibility of the proposed algorithm. PMID:26089971

Digital differential confocal microscopy based on spatial shift transformation.

PubMed

Liu, J; Wang, Y; Liu, C; Wilson, T; Wang, H; Tan, J

2014-11-01

Differential confocal microscopy is a particularly powerful surface profilometry technique in industrial metrology due to its high axial sensitivity and insensitivity to noise. However, the practical implementation of the technique requires the accurate positioning of point detectors in three-dimensions. We describe a simple alternative based on spatial transformation of a through-focus series of images obtained from a homemade beam scanning confocal microscope. This digital differential confocal microscopy approach is described and compared with the traditional Differential confocal microscopy approach. The ease of use of the digital differential confocal microscopy system is illustrated by performing measurements on a 3D standard specimen. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

CONSUMER PREFERENCES FOR SCANNING MODALITY TO DIAGNOSE FOCAL LIVER LESIONS.

PubMed

Whitty, Jennifer; Filby, Alexandra; Smith, Adam B; Carr, Louise M

2015-01-01

Differences in the process of using liver imaging technologies might be important to patients. This study aimed to investigate preferences for scanning modalities used in diagnosing focal liver lesions. A discrete choice experiment was administered to 504 adults aged 25 ≥years. Respondents made repeated choices between two hypothetical scans, described according to waiting time for scan and results, procedure type, the chance of minor side-effects, and whether further scanning procedures were likely to be required. Choice data were analyzed using mixed-logit models with respondent characteristics used to explain preference heterogeneity. Respondents preferred shorter waiting times, the procedure to be undertaken with a handheld scanner on a couch instead of within a body scanner, no side-effects, and no follow–up scans (p≤.01). The average respondent was willing to wait an additional 2 weeks for the scan if it resulted in avoiding side-effects, 1.5 weeks to avoid further procedures or to be told the results immediately, and 1 week to have the scan performed on a couch with a handheld scanner. However, substantial heterogeneity was observed in the strength of preference for desirable imaging characteristics. An average individual belonging to a general population sub–group most likely to require imaging to characterize focal liver lesions in the United Kingdom would prefer contrast–enhanced ultrasound over magnetic resonance imaging or computed tomography. Insights into the patient perspective around differential characteristics of imaging modalities have the potential to be used to guide recommendations around the use of these technologie

Pelvic CT scan

MedlinePlus

CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye CT scans do expose you to more radiation ...

Shoulder CT scan

MedlinePlus

CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye Birth defect if done during pregnancy CT scans ...

Sinus CT scan

MedlinePlus

CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... Risks for a CT scan includes: Being exposed to radiation Allergic reaction to contrast dye CT scans expose you to more radiation than regular ...

ScanImage: flexible software for operating laser scanning microscopes.

PubMed

Pologruto, Thomas A; Sabatini, Bernardo L; Svoboda, Karel

2003-05-17

Laser scanning microscopy is a powerful tool for analyzing the structure and function of biological specimens. Although numerous commercial laser scanning microscopes exist, some of the more interesting and challenging applications demand custom design. A major impediment to custom design is the difficulty of building custom data acquisition hardware and writing the complex software required to run the laser scanning microscope. We describe a simple, software-based approach to operating a laser scanning microscope without the need for custom data acquisition hardware. Data acquisition and control of laser scanning are achieved through standard data acquisition boards. The entire burden of signal integration and image processing is placed on the CPU of the computer. We quantitate the effectiveness of our data acquisition and signal conditioning algorithm under a variety of conditions. We implement our approach in an open source software package (ScanImage) and describe its functionality. We present ScanImage, software to run a flexible laser scanning microscope that allows easy custom design.

Line-scanning, stage scanning confocal microscope

NASA Astrophysics Data System (ADS)

Carucci, John A.; Stevenson, Mary; Gareau, Daniel

2016-03-01

We created a line-scanning, stage scanning confocal microscope as part of a new procedure: video assisted micrographic surgery (VAMS). The need for rapid pathological assessment of the tissue on the surface of skin excisions very large since there are 3.5 million new skin cancers diagnosed annually in the United States. The new design presented here is a confocal microscope without any scanning optics. Instead, a line is focused in space and the sample, which is flattened, is physically translated such that the line scans across its face in a direction perpendicular to the line its self. The line is 6mm long and the stage is capable of scanning 50 mm, hence the field of view is quite large. The theoretical diffraction-limited resolution is 0.7um lateral and 3.7um axial. However, in this preliminary report, we present initial results that are a factor of 5-7 poorer in resolution. The results are encouraging because they demonstrate that the linear array detector measures sufficient signal from fluorescently labeled tissue and also demonstrate the large field of view achievable with VAMS.

Cure Kinetics of Benzoxazine/Cycloaliphatic Epoxy Resin by Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Gouni, Sreeja Reddy

Understanding the curing kinetics of a thermoset resin has a significant importance in developing and optimizing curing cycles in various industrial manufacturing processes. This can assist in improving the quality of final product and minimizing the manufacturing-associated costs. One approach towards developing such an understanding is to formulate kinetic models that can be used to optimize curing time and temperature to reach a full cure state or to determine time to apply pressure in an autoclave process. Various phenomenological reaction models have been used in the literature to successfully predict the kinetic behavior of a thermoset system. The current research work was designed to investigate the cure kinetics of Bisphenol-A based Benzoxazine (BZ-a) and Cycloaliphatic epoxy resin (CER) system under isothermal and nonisothermal conditions by Differential Scanning Calorimetry (DSC). The cure characteristics of BZ-a/CER copolymer systems with 75/25 wt% and 50/50 wt% have been studied and compared to that of pure benzoxazine under nonisothermal conditions. The DSC thermograms exhibited by these BZ-a/CER copolymer systems showed a single exothermic peak, indicating that the reactions between benzoxazine-benzoxazine monomers and benzoxazine-cycloaliphatic epoxy resin were interactive and occurred simultaneously. The Kissinger method and isoconversional methods including Ozawa-Flynn-Wall and Freidman were employed to obtain the activation energy values and determine the nature of the reaction. The cure behavior and the kinetic parameters were determined by adopting a single step autocatalytic model based on Kamal and Sourour phenomenological reaction model. The model was found to suitably describe the cure kinetics of copolymer system prior to the diffusion-control reaction. Analyzing and understanding the thermoset resin system under isothermal conditions is also important since it is the most common practice in the industry. The BZ-a/CER copolymer system with

The effects of viscoelastic polymer substrates on adult stem cell differentiation

NASA Astrophysics Data System (ADS)

Chang, Chungchueh; Fields, Adam; Ramek, Alex; Jurukovski, Vladimir; Simon, Marcia; Rafailovich, Miriam

2009-03-01

Dental Pulp Stem Cells (DPSCs) are known to differentiate in either bone, dentine, or nerve tissue by different environment signals. In this study, we have determined whether differentiation could only through modification of the substrate mechanics. Atomic Force Microscopy (AFM) on Shear Modulation Force Microscopy (SMFM) mode indicated that the spun-cast polybutadiene (PB) thin films could be used to provide different stiffness substrates by changing the thicknesses of thin films. DPSCs were then plated on these substrates and cultured in standard media. After 28 days incubation, Lasar Scanning Confocal Microscopy (LSCM) with mercury lamp indicated that the crystals were observed only on hard surfaces. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX analysis) indicated that the crystals are calcium phosphates. The Glancing Incidence Diffraction (GID) was also used to determine the structure of crystals. These results indicate that DPSCs could be differentiated into osteoblasts by mechanical stimuli from substrate mechanics.

Thyroid scan

MedlinePlus

... thyroid; Radioactive iodine uptake and scan test - thyroid; Nuclear scan - thyroid ... the test. Ask your provider or the radiology/nuclear medicine team performing the scan about taking precautions.

An interchangeable scanning Hall probe/scanning SQUID microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin

2014-08-15

We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a widemore » range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.« less

Water absorption of freeze-dried meat at different water activities: a multianalytical approach using sorption isotherm, differential scanning calorimetry, and nuclear magnetic resonance.

PubMed

Venturi, Luca; Rocculi, Pietro; Cavani, Claudio; Placucci, Giuseppe; Dalla Rosa, Marco; Cremonini, Mauro A

2007-12-26

Hydration of freeze-dried chicken breast meat was followed in the water activity range of aw=0.12-0.99 by a multianalytical approach comprising of sorption isotherm, differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). The amount of frozen water and the shape of the T2-relaxogram were evaluated at each water content by DSC and NMR, respectively. Data revealed an agreement between sorption isotherm and DSC experiments about the onset of bulk water (aw=0.83-0.86), and NMR detected mobile water starting at aw=0.75. The origin of the short-transverse relaxation time part of the meat NMR signal was also reinvestigated through deuteration experiments and proposed to arise from protons belonging to plasticized matrix structures. It is proved both by D2O experiments and by gravimetry that the extra protons not contributing to the water content in the NMR experiments are about 6.4% of the total proton NMR CPMG signal of meat.

Leg CT scan

MedlinePlus

CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... CT scan makes detailed pictures of the body very quickly. The test may help look for: An abscess ...

Arm CT scan

MedlinePlus

CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Healing problems or scar tissue following surgery A CT scan may also be used to guide a surgeon ...

Nuclear Scans

MedlinePlus

Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

Accuracy of i-Scan for Optical Diagnosis of Colonic Polyps: A Meta-Analysis

PubMed Central

Guo, Chuan-Guo; Ji, Rui; Li, Yan-Qing

2015-01-01

Background i-Scan is a novel virtual chromoendoscopy system designed to enhance surface and vascular patterns to improve optical diagnostic performance. Numerous prospective studies have been done to evaluate the accuracy of i-Scan in differentiating colonic neoplasms from non-neoplasms. i-Scan could be an effective endoscopic technique for optical diagnosis of colonic polyps. Objective Our aim of this study was to perform a meta-analysis of published data to establish the diagnostic accuracy of i-Scan for optical diagnosis of colonic polyps. Methods We searched PubMed, Medline, Elsevier ScienceDirect and Cochrane Library databases. We used a bivariate meta-analysis following a random effects model to summarize the data and plotted hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve (AUC) serves as an indicator of the diagnostic accuracy. Results The meta-analysis included a total of 925 patients and 2312 polyps. For the overall studies, the area under the HSROC curve was 0.96. The summary sensitivity was 90.4% (95%CI 85%-94.1%) and specificity was 90.9% (95%CI 84.3%-94.9%). In 11 studies predicting polyps histology in real-time, the summary sensitivity and specificity was 91.5% (95%CI 85.7%-95.1%) and 92.1% (95%CI 84.5%-96.1%), respectively, with the AUC of 0.97. For three different diagnostic criteria (Kudo, NICE, others), the sensitivity was 86.3%, 93.0%, 85.0%, respectively and specificity was 84.8%, 94.4%, 91.8%, respectively. Conclusions Endoscopic diagnosis with i-Scan has accurate optical diagnostic performance to differentiate neoplastic from non-neoplastic polyps with an area under the HSROC curve exceeding 0.90. Both the sensitivity and specificity for diagnosing colonic polyps are over 90%. PMID:25978459

Static and (quasi)dynamic calibration of stroboscopic scanning white light interferometer

NASA Astrophysics Data System (ADS)

Seppä, Jeremias; Kassamakov, Ivan; Nolvi, Anton; Heikkinen, Ville; Paulin, Tor; Lassila, Antti; Hao, Ling; Hæggsröm, Edward

2013-04-01

A scanning white light interferometer can characterize out of plane features and motion in M(N)EMS devices. Like any other form and displacement measuring instrument, the scanning interferometer results should be linked to the metre definition to be comparable and unambiguous. Traceability is built up by careful error characterization and calibration of the interferometer. The main challenge in this calibration is to have a reference device producing accurate and reproducible dynamic out-of-plane displacement when submitted to standard loads. We use a flat mirror attached to a piezoelectric transducer for static and (quasi)dynamic calibration of a stroboscopic scanning light interferometer. First we calibrated the piezo-scanned flexure guided transducer stage using a symmetric differential heterodyne laser interferometer developed at the Centre for Metrology and Accreditation (MIKES). The standard uncertainty of the piezo stage motion calibration was 3.0 nm. Then we used the piezo-stage as a transfer standard to calibrate our stroboscopic interferometer whose light source was pulsed at 200 Hz and 400 Hz with 0.5% duty cycle. We measured the static position and (quasi)dynamic motion of the attached mirror relative to a reference surface. This methodology permits calibrating the vertical scale of the stroboscopic scanning white light interferometer.

Head CT scan

MedlinePlus

Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

Characterization of Gas Hydrate Samples from IODP 311 using High Resolution Raman Spectroscopy, X-ray Diffraction and Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Schicks, J. M.; Ziemann, M. A.; Naumann, R.; Erzinger, J.

2006-12-01

Investigations on hydrate bearing sediments taken from different locations (Gulf of Mexico, Sea of Okhotsk, etc.) lead to the conclusion that the coexistence of gas hydrates with different structures and compositions in nature is possible (Sassen et al. 2000, Takeya et al 2006). The aim of this study is to get more information about the variation in local composition of gas hydrates in samples from IODP Leg 311 (Hole 1328) using Raman spectroscopy. Therefore, in addition to investigations performed at the same samples by Lu et al., experiments in this study have been carried out with a confocal Raman microprobe in high lateral and spectral resolution mode. The samples have been analysed at 153 K and at atmospheric pressure (single spots, line scans, area mapping). The specified structure I hydrates contain methane and H2S. The Raman bands at 2569 cm-1 and 2593 cm-1 indicate H2S in large and small cages, respectively. Further information is provided about the variation of the CH4-H2S- composition and the cage occupancy of the sample. The samples have also been investigated with X-ray diffraction and differential scanning calorimetry (DSC). DSC measurements hint at the coexistence of two different gas hydrates with significantly different decomposition temperatures at atmospheric pressure (206 K and 247 K). This could be caused by variable amounts of H2S incorporated in the hydrate lattice. The results from the investigation on the IODP Leg 311 samples are compared and discussed with results of similar investigations on samples of structure I hydrate from Mallik 5L-38 drill hole in the permafrost of NW Canada. References: R. Sassen, S.T. Sweet, D.A. DeFreitas, A.V. Milkov, 2000. Organic Geochemistry, 31, 1257-1262. S. Takeya, M. Kida, H. Minami, H. Sakagami, A. Hachikubo, N. Takahashi, H. Shoji, V. Soloviev, K. Wallmann, N. Biebow, A. Obzhirov, A Salomatin, J. Poort, 2006. Chemical Engineering Science, 61, 2670- 2674.

Tetraether bolaform amphiphiles as models of archaebacterial membrane lipids: Synthesis, differential scanning calorimetry, and monolayer studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J.M.; Thompson, D.H.

Four racemic tetraether lipids containing a single 1,[omega]-polymethylene chain ([omega] = 16, 20) bridging two glycerophosphate headgroups (bolaform amphiphiles) have been synthesized. These materials have been characterized at the air-water interface by monolayer balance methods and in buffered solution by differential scanning calorimetry (DSC) and negative stain transmission electron microscopy (TEM). Molecular areas in excess of 100 [angstrom][sup 2]/molecule at 40 mN/m[sup 2] were observed for all bolaamphiphiles studied, suggesting a U-shaped molecular conformation that places both phosphate headgroups in the water subphase. Aqueous dispersions of these lipids have thermal and morphological properties that depend on molecular structure and solutionmore » pH. Phase transition temperatures (T[sub c]) of the structural isomers, 2,2[prime]-di-O-decyl-1, 1[prime]-O-eicosamethylene-rac-diglycero-3,3[prime]-diphosphate (PS20) and 1,1[prime]-di-O-decyl-2,2[prime]-O-eicosamethylene-3,3[prime]-diphosphate (SS20), were 49 and 38 [degrees]C, respectively, at pH 2.5. A reduction in the observed T[sub c] of [approximately] 14 [degrees]C occurred when the pH was raised to 8.1. The closely related structural analogue, 1,1[prime]-O-eicosamethylene-2-O-eicosyl-rac-diglycero-3,2[prime], 3[prime]-diphosphate (PA20), has a T[sub c] 85 [degrees]C. No phase transition was observed above 5 [degrees]C for 2,2[prime]-O-dioctyl-1,1 [prime]-O-hexadecylmethylene-rac-diglycero-3, 3[prime]-disphosphoric acid (PS16). Multilamellar structures with hydrocarbon-region spacings of 24-30 [angstrom] and overall lengths approaching 0.3 [mu]m were observed by negative stain electron microscopy. The observed lamellae distance is in good agreement with the membrane thickness expected for a bolaamphiphile in its all-anti conformation. 56 refs., 8 figs., 1 tab.« less

Ground Displacement Measurement of the 2013 Balochistan Earthquake with interferometric TerraSAR-X ScanSAR data

NASA Astrophysics Data System (ADS)

Yague-Martinez, N.; Fielding, E. J.; Haghshenas-Haghighi, M.; Cong, X.; Motagh, M.

2014-12-01

This presentation will address the 24 September 2013 Mw 7.7 Balochistan Earthquake in western Pakistan from the point of view of interferometric processing algorithms of wide-swath TerraSAR-X ScanSAR images. The algorithms are also valid for TOPS acquisition mode, the operational mode of the Sentinel-1A ESA satellite that was successfully launched in April 2014. Spectral properties of burst-mode data and an overview of the interferometric processing steps of burst-mode acquisitions, emphasizing the importance of the co-registration stage, will be provided. A co-registration approach based on incoherent cross-correlation will be presented and applied to seismic scenarios. Moreover geodynamic corrections due to differential atmospheric path delay and differential solid Earth tides are considered to achieve accuracy in the order of several centimeters. We previously derived a 3D displacement map using cross-correlation techniques applied to optical images from Landsat-8 satellite and TerraSAR-X ScanSAR amplitude images. The Landsat-8 cross-correlation measurements cover two horizontal directions, and the TerraSAR-X displacements include both horizontal along-track and slant-range (radar line-of-sight) measurements that are sensitive to vertical and horizontal deformation. It will be justified that the co-seismic displacement map from TerraSAR-X ScanSAR data may be contaminated by postseismic deformation due to the fact that the post-seismic acquisition took place one month after the main shock, confirmed in part by a TerraSAR-X stripmap interferogram (processed with conventional InSAR) covering part of the area starting on 27 September 2013. We have arranged the acquisition of a burst-synchronized stack of TerraSAR-X ScanSAR images over the affected area after the earthquake. It will be possible to apply interferometry to these data to measure the lower magnitude of the expected postseismic displacements. The processing of single interferograms will be discussed. A

Are All-Solid-State Lithium-Ion Batteries Really Safe?-Verification by Differential Scanning Calorimetry with an All-Inclusive Microcell.

PubMed

Inoue, Takao; Mukai, Kazuhiko

2017-01-18

Although all-solid-state lithium-ion batteries (ALIBs) have been believed as the ultimate safe battery, their true character has been an enigma so far. In this paper, we developed an all-inclusive-microcell (AIM) for differential scanning calorimetry (DSC) analysis to clarify the degree of safety (DOS) of ALIBs. Here AIM possesses all the battery components to work as a battery by itself, and DOS is determined by the total heat generation ratio (ΔH) of ALIB compared with the conventional LIB. When DOS = 100%, the safety of ALIB is exactly the same as that of LIB; when DOS = 0%, ALIB reaches the ultimate safety. We investigated two types of LIB-AIM and three types of ALIB-AIM. Surprisingly, all the ALIBs exhibit one or two exothermic peaks above 250 °C with 20-30% of DOS. The exothermic peak is attributed to the reaction between the released oxygen from the positive electrode and the Li metal in the negative electrode. Hence, ALIBs are found to be flammable as in the case of LIBs. We also attempted to improve the safety of ALIBs and succeeded in decreasing the DOS down to ∼16% by incorporating Ketjenblack into the positive electrode as an oxygen scavenger. Based on ΔH as a function of voltage window, a safety map for LIBs and ALIBs is proposed.

A comparison of sequential and spiral scanning techniques in brain CT.

PubMed

Pace, Ivana; Zarb, Francis

2015-01-01

To evaluate and compare image quality and radiation dose of sequential computed tomography (CT) examinations of the brain and spiral CT examinations of the brain imaged on a GE HiSpeed NX/I Dual Slice 2CT scanner. A random sample of 40 patients referred for CT examination of the brain was selected and divided into 2 groups. Half of the patients were scanned using the sequential technique; the other half were scanned using the spiral technique. Radiation dose data—both the computed tomography dose index (CTDI) and the dose length product (DLP)—were recorded on a checklist at the end of each examination. Using the European Guidelines on Quality Criteria for Computed Tomography, 4 radiologists conducted a visual grading analysis and rated the level of visibility of 6 anatomical structures considered necessary to produce images of high quality. The mean CTDI(vol) and DLP values were statistically significantly higher (P <.05) with the sequential scans (CTDI(vol): 22.06 mGy; DLP: 304.60 mGy • cm) than with the spiral scans (CTDI(vol): 14.94 mGy; DLP: 229.10 mGy • cm). The mean image quality rating scores for all criteria of the sequential scanning technique were statistically significantly higher (P <.05) in the visual grading analysis than those of the spiral scanning technique. In this local study, the sequential technique was preferred over the spiral technique for both overall image quality and differentiation between gray and white matter in brain CT scans. Other similar studies counter this finding. The radiation dose seen with the sequential CT scanning technique was significantly higher than that seen with the spiral CT scanning technique. However, image quality with the sequential technique was statistically significantly superior (P <.05).

[Scans without Evidence of Dopamine Deficit (SWEDDs)].

PubMed

Mukai, Yohei; Murata, Miho

2016-01-01

Dopamine transporter (DaT) single-photon emission computed tomography (SPECT) and [18F]fluoro-L-DOPA ([18F]DOPA) positron emission tomography (PET) facilitate the investigation of dopaminergic hypofunction in neurodegenerative diseases. DaT SPECT and [18F]DOPA PET have been adopted as survey tools in clinical trials. In a large study on Parkinson's disease, 4-15% of subjects clinically diagnosed with early-stage Parkinson's disease had normal dopaminergic functional imaging scans. These are called Scans without Evidence of Dopamine Deficit (SWEDDs), and are considered to represent a state different from Parkinson's disease. Neurological diseases that exhibit parkinsonism and have normal dopaminergic cells in the nigrostriatal system (e.g., essential tremor, psychogenic parkinsonism, DOPA-responsive dystonia, vascular parkinsonism, drug-induced parkinsonism, manganism, brain tumor, myoclonus-dystonia (DYT11), and fragile X syndrome) might be diagnosed with SWEDDs. True bradykinesia with fatigue or decrement may be useful for distinguishing between Parkinson's disease and SWEDDs. However, because SWEDDs encompass many diseases, their properties may not be uniform. In this review, we discuss DaT SPECT, the concept of SWEDDs, and differential diagnosis.

Tip/tilt-compensated through-focus scanning optical microscopy

NASA Astrophysics Data System (ADS)

Lee, Jun Ho; Park, Jun Hyung; Jeong, Dohwan; Shin, Eun Ji; Park, Chris

2016-11-01

Through-Focus Optical Microscopy (TSOM), with nanometer scale lateral and vertical sensitivity matching those of scanning electron microscopy, has been demonstrated to be utilized for 3D inspection and metrology. There have been sensitivity and instability issues in acquiring through-focus images because TSOM 3D information is indirectly extracted by differentiating a target TSOM image from reference TSOM images. This paper first reports on the optical axis instability that occurs during the scanning process of TSOM when implemented in an existing patterned wafer inspection tool by moving the wafer plane; this is followed by quantitative confirmation of the optical/mechanical instability using a new TSOM tool on an optical bench with a Shack-Hartmann wavefront sensor and a tip/tilt sensor. Then, this paper proposes two tip/tilt compensated TSOM optical acquisition methods that can be applied with adaptive optics. The first method simply adopts a tip/tilt mirror with a quad cell in a simple closed loop, while the second method adopts a highorder deformable mirror with a Shack-Hartmann sensor. The second method is able to correct high-order residual aberrations as well as to perform through-focus scanning without z-axis movement, while the first method is easier to implement in pre-existing wafer inspection systems with only minor modification.

A log-Weibull spatial scan statistic for time to event data.

PubMed

Usman, Iram; Rosychuk, Rhonda J

2018-06-13

Spatial scan statistics have been used for the identification of geographic clusters of elevated numbers of cases of a condition such as disease outbreaks. These statistics accompanied by the appropriate distribution can also identify geographic areas with either longer or shorter time to events. Other authors have proposed the spatial scan statistics based on the exponential and Weibull distributions. We propose the log-Weibull as an alternative distribution for the spatial scan statistic for time to events data and compare and contrast the log-Weibull and Weibull distributions through simulation studies. The effect of type I differential censoring and power have been investigated through simulated data. Methods are also illustrated on time to specialist visit data for discharged patients presenting to emergency departments for atrial fibrillation and flutter in Alberta during 2010-2011. We found northern regions of Alberta had longer times to specialist visit than other areas. We proposed the spatial scan statistic for the log-Weibull distribution as a new approach for detecting spatial clusters for time to event data. The simulation studies suggest that the test performs well for log-Weibull data.

Total nucleated cell and leukocyte differential counts in canine pleural and peritoneal fluid and equine synovial fluid samples: comparison of automated and manual methods.

PubMed

Brudvig, Jean M; Swenson, Cheryl L

2015-12-01

Rapid and precise measurement of total and differential nucleated cell counts is a crucial diagnostic component of cavitary and synovial fluid analyses. The objectives of this study included (1) evaluation of reliability and precision of canine and equine fluid total nucleated cell count (TNCC) determined by the benchtop Abaxis VetScan HM5, in comparison with the automated reference instruments ADVIA 120 and the scil Vet abc, respectively, and (2) comparison of automated with manual canine differential nucleated cell counts. The TNCC and differential counts in canine pleural and peritoneal, and equine synovial fluids were determined on the Abaxis VetScan HM5 and compared with the ADVIA 120 and Vet abc analyzer, respectively. Statistical analyses included correlation, least squares fit linear regression, Passing-Bablok regression, and Bland-Altman difference plots. In addition, precision of the total cell count generated by the VetScan HM5 was determined. Agreement was excellent without significant constant or proportional bias for canine cavitary fluid TNCC. Automated and manual differential counts had R(2)  < .5 for individual cell types (least squares fit linear regression). Equine synovial fluid TNCC agreed but with some bias due to the VetScan HM5 overestimating TNCC compared to the Vet abc. Intra-assay precision of the VetScan HM5 in 3 fluid samples was 2-31%. The Abaxis VetScan HM5 provided rapid, reliable TNCC for canine and equine fluid samples. The differential nucleated cell count should be verified microscopically as counts from the VetScan HM5 and also from the ADVIA 120 were often incorrect in canine fluid samples. © 2015 American Society for Veterinary Clinical Pathology.

Pulmonary aspergilloma: A rare differential diagnosis to lung cancer after positive FDG PET scan

PubMed Central

Spycher, Franziska; Kocher, Gregor J.; Gugger, Mathias; Geiser, Thomas; Ott, Sebastian R.

2014-01-01

Early diagnosis and treatment of lung cancer, one of the leading causes of cancer-related death, is important to improve morbidity and mortality. Therefore any suspect solitary pulmonary nodule should prompt the pursuit for a definitive histological diagnosis. We describe the case of a 55-years-old male ex-smoker, who was admitted to our hospital due to recurrent hemoptysis and dry cough. A CT scan showed an irregular nodule of increasing size (28 mm in diameter) in the left lower lobe (LLL). A whole body PET-CT scan (643 MBq F-18 FDG i.v.) was performed and confirmed an avid FDG uptake of the nodule in the LLL, highly suspicious of lung cancer, without any evidence of lymphogenic or hematogenic metastasis. Bronchoscopy was not diagnostic and due to severe adhesions after prior chest trauma and the central location of the nodule, a lobectomy of the LLL was performed. Surprisingly, histology showed a simple aspergilloma located in a circumscribed bronchiectasis with no evidence of malignancy. This is a report of an informative example of an aspergilloma, which presented with symptoms and radiological features of malignant lung cancer. PMID:26029524

Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro

2016-01-28

Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.

Preablation 131-I scans with SPECT/CT in postoperative thyroid cancer patients: what is the impact on staging?

PubMed

Avram, Anca M; Fig, Lorraine M; Frey, Kirk A; Gross, Milton D; Wong, Ka Kit

2013-03-01

The utility of preablation radioiodine scans for the management of differentiated thyroid cancer remains controversial. To determine the contribution of preablation Iodine 131 (131-I) planar with single-photon emission computed tomography/computed tomography (SPECT/CT; diagnostic [Dx] scans) to differentiated thyroid cancer staging. Prospective sequential series at university clinic. Using American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) staging, seventh edition 320 patients post-total thyroidectomy were initially staged based on clinical and pathology data (pTN) and then restaged after imaging (TNM). The impact of Dx scans with SPECT/CT on N and M scores, and TNM stage, was assessed in younger, age <45 years, n = 138 (43%), and older, age ≥ 45 years, n = 182 (57%) patients, with subgroup analysis for T1a and T1b tumors. In younger patients Dx scans detected distant metastases in 5 of 138 patients (4%), and nodal metastases in 61 of 138 patients (44%), including unsuspected nodal metastases in 24 of 63 (38%) patients initially assigned pathologic (p) N0 or pNx. In older patients distant metastases were detected in 18 of 182 patients (10%), and nodal metastases in 51 of 182 patients (28%), including unsuspected nodal metastases in 26 of 108 (24%) patients initially assigned pN0 or pNx. Dx scans detected distant metastases in 2 of 49 (4%) T1a, and 3 of 67 (4.5%) T1b patients. Dx scans detected regional metastases in 35% of patients, and distant metastases in 8% of patients. Information acquired with Dx scans changed staging in 4% of younger, and 25% of older patients. Preablation scans with SPECT/CT contribute to staging of thyroid cancer. Identification of regional and distant metastases prior to radioiodine therapy has significant potential to alter patient management.

Differentiating Ferroelectric and Nonferroelectric Electromechanical Effects with Scanning Probe Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balke, Nina; Maksymovych, Petro; Jesse, Stephen

Ferroelectricity in functional materials remains one of the most fascinating areas of modern science in the past several decades. In the last several years, the rapid development of piezoresponse force microscopy (PFM) and spectroscopy revealed the presence of electromechanical hysteresis loops and bias-induced remnant polar states in a broad variety of materials including many inorganic oxides, polymers, and biosystems. In many cases, this behavior was interpreted as the ample evidence for ferroelectric nature of the system. Here, we systematically analyze PFM responses on ferroelectric and nonferroelectric materials and demonstrate that mechanisms unrelated to ferroelectricity can induce ferroelectric-like characteristics through chargemore » injection and electrostatic forces on the tip. In this paper, we will focus on similarities and differences in various PFM measurement characteristics to provide an experimental guideline to differentiate between ferroelectric material properties and charge injection. In conclusion, we apply the developed measurement protocols to an unknown ferroelectric material.« less

Differentiating Ferroelectric and Nonferroelectric Electromechanical Effects with Scanning Probe Microscopy

DOE PAGES

Balke, Nina; Maksymovych, Petro; Jesse, Stephen; ...

2015-06-02

Ferroelectricity in functional materials remains one of the most fascinating areas of modern science in the past several decades. In the last several years, the rapid development of piezoresponse force microscopy (PFM) and spectroscopy revealed the presence of electromechanical hysteresis loops and bias-induced remnant polar states in a broad variety of materials including many inorganic oxides, polymers, and biosystems. In many cases, this behavior was interpreted as the ample evidence for ferroelectric nature of the system. Here, we systematically analyze PFM responses on ferroelectric and nonferroelectric materials and demonstrate that mechanisms unrelated to ferroelectricity can induce ferroelectric-like characteristics through chargemore » injection and electrostatic forces on the tip. In this paper, we will focus on similarities and differences in various PFM measurement characteristics to provide an experimental guideline to differentiate between ferroelectric material properties and charge injection. In conclusion, we apply the developed measurement protocols to an unknown ferroelectric material.« less

An Inquiry-Based Project Focused on the X-Ray Powder Diffraction Analysis of Common Household Solids

ERIC Educational Resources Information Center

Hulien, Molly L.; Lekse, Jonathan W.; Rosmus, Kimberly A.; Devlin, Kasey P.; Glenn, Jennifer R.; Wisneski, Stephen D.; Wildfong, Peter; Lake, Charles H.; MacNeil, Joseph H.; Aitken, Jennifer A.

2015-01-01

While X-ray powder diffraction (XRPD) is a fundamental analytical technique used by solid-state laboratories across a breadth of disciplines, it is still underrepresented in most undergraduate curricula. In this work, we incorporate XRPD analysis into an inquiry-based project that requires students to identify the crystalline component(s) of…

Effectiveness and usability of Scanning Wizard software: a tool for enhancing switch scanning.

PubMed

Koester, Heidi Horstmann; Simpson, Richard C

2017-11-24

Scanning Wizard software helps scanning users improve the setup of their switch and scanning system. This study evaluated Scanning Wizard's effectiveness and usability. Ten people who use switch scanning and ten practitioners used Scanning Wizard in the initial session. Usability was high, based on survey responses averaging over 4.5 out of 5, and qualitative feedback was very positive. Five switch users were able to complete the multi-week protocol, using settings on their own scanning system that were recommended from the Scanning Wizard session. Using these revised settings, text entry rates improved by an average of 71%, ranging from 29% to 172% improvement. Results suggest that Scanning Wizard is a useful tool for improving the configuration of scanning systems for people who use switch scanning to communicate. Implications for Rehabilitation Some individuals with severe physical impairments use switch scanning for spoken and written communication. Scanning Wizard software helps scanning users improve the setup of their switch and scanning system. This study demonstrated high usability of Scanning Wizard (with 10 switch userpractitioner teams) and increased text entry rate by an average of 71% (for five switch users). Results suggest that Scanning Wizard is a useful tool for improving the configuration of scanning systems for people who use switch scanning to communicate.

An evaluation of the transition temperature range of super-elastic orthodontic NiTi springs using differential scanning calorimetry.

PubMed

Barwart, O; Rollinger, J M; Burger, A

1999-10-01

Differential scanning calorimetry (DSC) was used to determine the transition temperature ranges (TTR) of four types of super-elastic orthodontic nickel-titanium coil springs (Sentalloy). A knowledge of the TTR provides information on the temperature at which a NiTi wire or spring can assume superelastic properties and when this quality disappears. The spring types in this study can be distinguished from each other by their characteristic TTR during cooling and heating. For each tested spring type a characteristic TTR during heating (austenite transformation) and cooling (martensite transformation) was evaluated. The hysteresis of the transition temperature, found between cooling and heating, was 3.4-5.2 K. Depending on the spring type the austenite transformation started (As) at 9.7-17.1 degrees C and finished (Af) at 29.2-37 degrees C. The martensite transformation starting temperature (Ms) was evaluated at 32.6-25.4 degrees C, while Mf (martensite transformation finishing temperature) was 12.7-6.5 degrees C. The results show that the springs become super-elastic when the temperature increases and As is reached. They undergo a loss of super-elastic properties and a rapid decrease in force delivery when they are cooled to Mf. For the tested springs, Mf and As were found to be below room temperature. Thus, at room temperature and some degrees lower, all the tested springs exert super-elastic properties. For orthodontic treatment this means the maintenance of super-elastic behaviour, even when mouth temperature decreases to about room temperature as can occur, for example, during meals.

Development and characterisation of semi-crystalline composite granules: The effect of particle chemistry and the electrostatic charging

NASA Astrophysics Data System (ADS)

Haque, Syed N.; Hussain, Tariq; Chowdhry, Babur Z.; Douroumis, Dennis; Scoutaris, Nikolaos; Nokhodchi, Ali; Maniruzzaman, Mohammed

2017-12-01

This study investigated the surface of semi-crystalline composite granules produced via a novel mechano-chemical process and assessed the effect of electrostatic charging. Ibuprofen (IBU), a model drug with low solubility and known associated processing challenges was loaded in composite granules to improve its processibility and dissolution rates. Synthetic amorphous mesoporous magnesium alumina metasilicate (MAS) was co-processed with hydrophilic HPMC polymer in the presence of polyethylene glycol 2000 (PEG) and deionised water. The solid state analyses conducted by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) revealed the existence of semi-crystalline IBU in the complex composite structures. Dynamic vapour sorption (DVS) study showed the water sorption and desorption profiles of the manufactured composite granules as well as the effect of water on the solid-state stability of IBU in various formulations. Advanced surface analysis conducted via energy dispersive X-ray (EDS) revealed homogenous distribution of the drug/excipients on the surface of the granules while atomic force microscopy (AFM) complemented the findings. The electrostatic charge analysis showed variable charge property which is affected by the size of the particles/granules. As expected, the in vitro dissolution study showed about 5 fold increase in the release rates of IBU compared to that of the bulk drug. The mechanochemical processing has been demonstrated as an efficient technique to develop semi-crystalline composite granules with enhanced dissolution rates of water insoluble drugs.

A New Ka-Band Scanning Radar Facility: Polarimetric and Doppler Spectra Measurements of Snow Events

NASA Astrophysics Data System (ADS)

Oue, M.; Kollias, P.; Luke, E. P.; Mead, J.

2017-12-01

Polarimetric radar analyses offer the capability of identification of ice hydrometeor species as well as their spatial distributions. In addition to polarimetric parameter observations, Doppler spectra measurements offer unique insights into ice particle properties according to particle fall velocities. In particular, millimeter-wavelength radar Doppler spectra can reveal supercooled liquid cloud droplets embedded in ice precipitation clouds. A Ka-band scanning polarimetric radar, named KASPR, was installed in an observation facility at Stony Brook University, located 22 km west of the KOKX NEXRAD radar at Upton, NY. The KASPR can measure Doppler spectra and full polarimetric variables, including radar reflectivity, differential reflectivity (ZDR), differential phase (φDP), specific differential phase (KDP), correlation coefficient (ρhv), and linear depolarization ratio (LDR). The facility also includes a micro-rain radar and a microwave radiometer capable of measuring reflectivity profiles and integrated liquid water path, respectively. The instruments collected initial datasets during two snowstorm events and two snow shower events in March 2017. The radar scan strategy was a combination of PPI scans at 4 elevation angles (10, 20, 45, and 60°) and RHI scans in polarimetry mode, and zenith pointing with Doppler spectra collection. During the snowstorm events the radar observed relatively larger ZDR (1-1.5 dB) and enhanced KDP (1-2 ° km-1) at heights corresponding to a plate/dendrite crystal growth regime. The Doppler spectra showed that slower-falling particles (< 0.5 m s-1) coexisted with faster-falling particles (> 1 m s-1). The weakly increased ZDR could be produced by large, faster falling particles such as quasi-spherical aggregates, while the enhanced KDP could be produced by highly-oriented oblate, slowly-falling particles. Below 2 km altitude, measurements of dual wavelength ratio (DWR) based on Ka and S-band reflectivities from the KASPR and NEXRAD

Differentiating defects in red oak lumber by discriminant analysis using color, shape, and density

Treesearch

B. H. Bond; D. Earl Kline; Philip A. Araman

2002-01-01

Defect color, shape, and density measures aid in the differentiation of knots, bark pockets, stain/mineral streak, and clearwood in red oak, (Quercus rubra). Various color, shape, and density measures were extracted for defects present in color and X-ray images captured using a color line scan camera and an X-ray line scan detector. Analysis of variance was used to...

Malignant mesothelioma with squamous differentiation.

PubMed

Tanaka, Hiroyuki; Akiyama, Yutaka; Kitamura, Akiko; Matsumoto, Nobuhiro; Tomita, Masaki; Kataoka, Hiroaki

2018-06-01

We report the autopsy findings of a 58-year-old man with malignant mesothelioma in the left pleural cavity. The patient had a history of asbestos exposure, and the chest computed tomography scan on initial admission demonstrated an extrapleural sign, suggesting a nodular lesion in the chest wall. However, no nodular lesions were detectable in either of his lungs. In spite of chemotherapy, he died 4 months after the initial admission. An autopsy revealed markedly thickened pleura in a large section of the left pleural cavity without visible intrapulmonary primary tumour lesions. Histological examination of a biopsy specimen obtained prior to chemotherapy and that of an autopsy specimen showed that the pleural tumour was composed of a mixture of mesothelioma and tumour cells with squamous differentiation mimicking squamous cell carcinoma. To the best of our knowledge, this is the first case report of mesothelioma with extensive squamous differentiation in the English-language literature. The extensive squamous differentiation reminiscent of squamous cell carcinoma can be a pitfall in the pathological diagnosis of pleural cytology and that of biopsy specimens from patients with mesothelioma. Here, we report autopsy findings of a case of malignant mesothelioma with portions of extensive squamous differentiation, mimicking a squamous cell carcinoma. © 2018 John Wiley & Sons Ltd.

The Scanning Nanoprobe Beamline Nanoscopium at Synchrotron Soleil

NASA Astrophysics Data System (ADS)

Somogyi, A.; Kewish, C. M.; Polack, F.; Moreno, T.

2011-09-01

The Nanoscopium beamline at Synchrotron Soleil will offer advanced scanning-based hard x-ray imaging techniques in the 5- to 20-keV energy range, for user communities working in the earth, environmental, and life sciences. Two dedicated end stations will exploit x-ray coherence to produce images in which contrast is based on a range of physical processes. In the first experiment hutch, coherent scatter imaging techniques will produce images in which contrast arises from spatial variations in the complex refractive index, and orientation in the nanostructure of samples. In the second experiment hutch, elemental mapping will be carried out at the trace (ppm) level by scanning x-ray fluorescence, speciation mapping by XANES, and phase gradient mapping by scanning differential phase contrast imaging. The beamline aims to reach sub-micrometric, down to 30 nm, spatial resolution. This ˜155-meter-long beamline will share the straight section with a future tomography beamline by using canted undulators having 6.5-mrad separation angle. The optical design of Nanoscopium aims to reduce the effect of instabilities on the probing nanobeam by utilizing an all-horizontal geometry for the reflections of the primary beamline mirrors, which focus onto a slit, creating an over-filled secondary source. Kirkpatrick-Baez mirrors and Fresnel zone plates will be used as focusing devices in the experiment hutches. Nanoscopium is expected to commence user operation in 2013.

Gallbladder radionuclide scan

MedlinePlus

... Gallbladder scan; Biliary scan; Cholescintigraphy; HIDA; Hepatobiliary nuclear imaging scan ... test results. This test is combined with other imaging (such as CT or ultrasound). After the gallbladder ...

Theoretical Aspects of Differential Scanning Calorimetry as a Tool for the Studies of Equilibrium Thermodynamics in Pharmaceutical Solid Phase Transitions.

PubMed

Faroongsarng, Damrongsak

2016-06-01

Although differential scanning calorimetry (DSC) is a non-equilibrium technique, it has been used to gain energetic information that involves phase equilibria. DSC has been widely used to characterize the equilibrium melting parameters of small organic pharmaceutical compounds. An understanding of how DSC measures an equilibrium event could make for a better interpretation of the results. The aim of this mini-review was to provide a theoretical insight into the DSC measurement to obtain the equilibrium thermodynamics of a phase transition especially the melting process. It was demonstrated that the heat quantity obtained from the DSC thermogram (ΔH) was related to the thermodynamic enthalpy of the phase transition (ΔH (P) ) via: ΔH = ΔH (P) /(1 + K (- 1)) where K was the equilibrium constant. In melting, the solid and liquefied phases presumably coexist resulting in a null Gibbs free energy that produces an infinitely larger K. Thus, ΔH could be interpreted as ΔH (P). Issues of DSC investigations on melting behavior of crystalline solids including polymorphism, degradation impurity due to heating in situ, and eutectic melting were discussed. In addition, DSC has been a tool for determination of the impurity based on an ideal solution of the melt that is one of the official methods used to establish the reference standard.

Cholesterol affects the interaction between an ionic liquid and phospholipid vesicles. A study by differential scanning calorimetry and nanoplasmonic sensing.

PubMed

Russo, Giacomo; Witos, Joanna; Rantamäki, Antti H; Wiedmer, Susanne K

2017-12-01

The present work aims at studying the interactions between cholesterol-rich phosphatidylcholine-based lipid vesicles and trioctylmethylphosphonium acetate ([P 8881 ][OAc]), a biomass dissolving ionic liquid (IL). The effect of cholesterol was assayed by using differential scanning calorimetry (DSC) and nanoplasmonic sensing (NPS) measurement techniques. Cholesterol-enriched dipalmitoyl-phosphatidylcholine vesicles were exposed to different concentrations of the IL, and the derived membrane perturbation was monitored by DSC. The calorimetric data could suggest that the binding and infiltration of the IL are delayed in the vesicles containing cholesterol. To clarify our findings, NPS was applied to quantitatively follow the resistance of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine incorporating 0, 10, and 50mol% of cholesterol toward the IL exposure over time. The membrane perturbation induced by different concentrations of IL was found to be a concentration dependent process on cholesterol-free lipid vesicles. Moreover, our results showed that lipid depletion in cholesterol-enriched lipid vesicles is inversely proportional to the increasing amount of cholesterol in the vesicles. These findings support that cholesterol-rich lipid bilayers are less susceptible toward membrane disrupting agents as compared to membranes that do not incorporate any sterols. This probably occurs because cholesterol tightens the phospholipid acyl chain packing of the plasma membranes, increasing their resistance and reducing their permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

Statistical image quantification toward optimal scan fusion and change quantification

NASA Astrophysics Data System (ADS)

Potesil, Vaclav; Zhou, Xiang Sean

2007-03-01

Recent advance of imaging technology has brought new challenges and opportunities for automatic and quantitative analysis of medical images. With broader accessibility of more imaging modalities for more patients, fusion of modalities/scans from one time point and longitudinal analysis of changes across time points have become the two most critical differentiators to support more informed, more reliable and more reproducible diagnosis and therapy decisions. Unfortunately, scan fusion and longitudinal analysis are both inherently plagued with increased levels of statistical errors. A lack of comprehensive analysis by imaging scientists and a lack of full awareness by physicians pose potential risks in clinical practice. In this paper, we discuss several key error factors affecting imaging quantification, studying their interactions, and introducing a simulation strategy to establish general error bounds for change quantification across time. We quantitatively show that image resolution, voxel anisotropy, lesion size, eccentricity, and orientation are all contributing factors to quantification error; and there is an intricate relationship between voxel anisotropy and lesion shape in affecting quantification error. Specifically, when two or more scans are to be fused at feature level, optimal linear fusion analysis reveals that scans with voxel anisotropy aligned with lesion elongation should receive a higher weight than other scans. As a result of such optimal linear fusion, we will achieve a lower variance than naïve averaging. Simulated experiments are used to validate theoretical predictions. Future work based on the proposed simulation methods may lead to general guidelines and error lower bounds for quantitative image analysis and change detection.

Measuring the temperature dependent thermal diffusivity of geomaterials using high-speed differential scanning calorimetry

NASA Astrophysics Data System (ADS)

von Aulock, Felix W.; Wadsworth, Fabian B.; Vasseur, Jeremie; Lavallée, Yan

2016-04-01

Heat diffusion in the Earth's crust is critical to fundamental geological processes, such as the cooling of magma, heat dissipation during and following transient heating events (e.g. during frictional heating along faults), and to the timescales of contact metamorphosis. The complex composition and multiphase nature of geomaterials prohibits the accurate modeling of thermal diffusivities and measurements over a range of temperatures are sparse due to the specialized nature of the equipment and lack of instrument availability. We present a novel method to measure the thermal diffusivity of geomaterials such as minerals and rocks with high precision and accuracy using a commercially available differential scanning calorimeter (DSC). A DSC 404 F1 Pegasus® equipped with a Netzsch high-speed furnace was used to apply a step-heating program to corundum single crystal standards of varying thicknesses. The standards were cylindrical discs of 0.25-1 mm thickness with 5.2-6 mm diameter. Heating between each 50 °C temperature interval was conducted at a rate of 100 °C/min over the temperature range 150-1050 °C. Such large heating rates induces temperature disequilibrium in the samples used. However, isothermal segments of 2 minutes were used during which the temperature variably equilibrated with the furnace between the heating segments and thus the directly-measured heat-flow relaxed to a constant value before the next heating step was applied. A finite-difference 2D conductive heat transfer model was used in cylindrical geometry for which the measured furnace temperature was directly applied as the boundary condition on the sample-cylinder surfaces. The model temperature was averaged over the sample volume per unit time and converted to heat-flow using the well constrained thermal properties for corundum single crystals. By adjusting the thermal diffusivity in the model solution and comparing the resultant heat-flow with the measured values, we obtain a model

Frequency-Agile Differential Cavity Ring-Down Spectroscopy

NASA Astrophysics Data System (ADS)

Reed, Zachary; Hodges, Joseph

2015-06-01

The ultimate precision of highly sensitive cavity-enhanced spectroscopic measurements is often limited by interferences (etalons) caused by weak coupled-cavity effects. Differential measurements of ring-down decay constants have previously been demonstrated to largely cancel these effects, but the measurement acquisition rates were relatively low [1,2]. We have previously demonstrated the use of frequency agile rapid scanning cavity ring-down spectroscopy (FARS-CRDS) for acquisition of absorption spectra [3]. Here, the method of rapidly scanned, frequency-agile differential cavity ring-down spectroscopy (FADS-CRDS) is presented for reducing the effect of these interferences and other shot-to-shot statistical variations in measured decay times. To this end, an electro-optic phase modulator (EOM) with a bandwidth of 20 GHz is driven by a microwave source, generating pairs of sidebands on the probe laser. The optical resonator acts as a highly selective optical filter to all laser frequencies except for one tunable sideband. This sideband may be stepped arbitrarily from mode-to-mode of the ring-down cavity, at a rate limited only by the cavity buildup/decay time. The ability to probe any cavity mode across the EOM bandwidth enables a variety of methods for generating differential spectra. The differential mode spacing may be changed, and the effect of this method on suppressing the various coupled-cavity interactions present in the system is discussed. Alternatively, each mode may also be differentially referenced to a single point, providing immunity to temporal variations in the base losses of the cavity while allowing for conventional spectral fitting approaches. Differential measurements of absorption are acquired at 3.3 kHz and a minimum detectable absorption coefficient of 5 x10-12 cm-1 in 1 s averaging time is achieved. 1. J. Courtois, K. Bielska, and J.T Hodges J. Opt. Soc. Am. B, 30, 1486-1495, 2013 2. H.F. Huang and K.K. Lehmann App. Optics 49, 1378

Development of fast parallel multi-technique scanning X-ray imaging at Synchrotron Soleil

NASA Astrophysics Data System (ADS)

Medjoubi, K.; Leclercq, N.; Langlois, F.; Buteau, A.; Lé, S.; Poirier, S.; Mercère, P.; Kewish, C. M.; Somogyi, A.

2013-10-01

A fast multimodal scanning X-ray imaging scheme is prototyped at Soleil Synchrotron. It permits the simultaneous acquisition of complementary information on the sample structure, composition and chemistry by measuring transmission, differential phase contrast, small-angle scattering, and X-ray fluorescence by dedicated detectors with ms dwell time per pixel. The results of the proof of principle experiments are presented in this paper.

A differential scanning calorimetric study of the effects of metal ions, substrate/product, substrate analogues and chaotropic anions on the thermal denaturation of yeast enolase 1.

PubMed

Brewer, J M; Wampler, J E

2001-03-14

The thermal denaturation of yeast enolase 1 was studied by differential scanning calorimetry (DSC) under conditions of subunit association/dissociation, enzymatic activity or substrate binding without turnover and substrate analogue binding. Subunit association stabilizes the enzyme, that is, the enzyme dissociates before denaturing. The conformational change produced by conformational metal ion binding increases thermal stability by reducing subunit dissociation. 'Substrate' or analogue binding additionally stabilizes the enzyme, irrespective of whether turnover is occurring, perhaps in part by the same mechanism. More strongly bound metal ions also stabilize the enzyme more, which we interpret as consistent with metal ion loss before denaturation, though possibly the denaturation pathway is different in the absence of metal ion. We suggest that some of the stabilization by 'substrate' and analogue binding is owing to the closure of moveable polypeptide loops about the active site, producing a more 'closed' and hence thermostable conformation.

Multi-scale Imaging of Cellular and Sub-cellular Structures using Scanning Probe Recognition Microscopy.

NASA Astrophysics Data System (ADS)

Chen, Q.; Rice, A. F.

2005-03-01

Scanning Probe Recognition Microscopy is a new scanning probe capability under development within our group to reliably return to and directly interact with a specific nanobiological feature of interest. In previous work, we have successfully recognized and classified tubular versus globular biological objects from experimental atomic force microscope images using a method based on normalized central moments [ref. 1]. In this paper we extend this work to include recognition schemes appropriate for cellular and sub-cellular structures. Globular cells containing tubular actin filaments are under investigation. Thus there are differences in external/internal shapes and scales. Continuous Wavelet Transform with a differential Gaussian mother wavelet is employed for multi- scale analysis. [ref. 1] Q. Chen, V. Ayres and L. Udpa, ``Biological Investigation Using Scanning Probe Recognition Microscopy,'' Proceedings 3rd IEEE Conference on Nanotechnology, vol. 2, p 863-865 (2003).

Abdominal CT scan

MedlinePlus

Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... An abdominal CT scan makes detailed pictures of the structures inside your belly very quickly. This test may be used to look ...

[MRI and CT-scan in presumed benign ovarian tumors].

PubMed

Thomassin-Naggara, I; Bazot, M

2013-12-01

Radiological examinations are required for the assessment of complex or indeterminate ovarian masses, mainly using MRI and CT-scan. MRI provides better tissue characterization than Doppler ultrasound or CT-scan (LE2). Pelvic MRI is recommended in case of an indeterminate or complex ovarian ultrasonographic mass (grade B). The protocol of a pelvic MRI should include morphological T1 and T2 sequences (grade B). In case of solid portion, perfusion and diffusion sequences are recommended (grade C). In case of doubt about the diagnosis of ovarian origin, pelvic MRI is preferred over the CT-scan (grade C). MRI is the technique of choice for the difference between functional and organic ovarian lesion diagnosis (grade C). It can be useful in case of clinical diagnostic uncertainty between polycystic ovary syndrome and ovarian hyperstimulation and multilocular ovarian tumor syndrome (grade C). No MRI classification for ovarian masses is currently validated. The establishment of a presumption of risk of malignancy is required in a MRI report of adnexal mass with if possible a guidance on the histological diagnosis. In the absence of clinical or sonographic diagnosis, pelvic CT-scan is recommended in the context of acute painful pelvic mass in non-pregnant patients (grade C). It specifies the anomalies and allows the differential diagnosis with digestive and urinary diseases (LE4). Given the lack of data in the literature, the precautionary principle must be applied to the realization of a pelvic MRI in a pregnant patient. A risk-benefit balance should be evaluated case by case by the clinician and the radiologist and information should be given to the patient. In an emergency situation during pregnancy, pelvic MRI is an alternative to CT-scan for the exploration of acute pelvic pain in case of uncertain sonographic diagnosis (grade C). Copyright © 2013. Published by Elsevier Masson SAS.

Application and interpretation of functional data analysis techniques to differential scanning calorimetry data from lupus patients.

PubMed

Kendrick, Sarah K; Zheng, Qi; Garbett, Nichola C; Brock, Guy N

2017-01-01

DSC is used to determine thermally-induced conformational changes of biomolecules within a blood plasma sample. Recent research has indicated that DSC curves (or thermograms) may have different characteristics based on disease status and, thus, may be useful as a monitoring and diagnostic tool for some diseases. Since thermograms are curves measured over a range of temperature values, they are considered functional data. In this paper we apply functional data analysis techniques to analyze differential scanning calorimetry (DSC) data from individuals from the Lupus Family Registry and Repository (LFRR). The aim was to assess the effect of lupus disease status as well as additional covariates on the thermogram profiles, and use FD analysis methods to create models for classifying lupus vs. control patients on the basis of the thermogram curves. Thermograms were collected for 300 lupus patients and 300 controls without lupus who were matched with diseased individuals based on sex, race, and age. First, functional regression with a functional response (DSC) and categorical predictor (disease status) was used to determine how thermogram curve structure varied according to disease status and other covariates including sex, race, and year of birth. Next, functional logistic regression with disease status as the response and functional principal component analysis (FPCA) scores as the predictors was used to model the effect of thermogram structure on disease status prediction. The prediction accuracy for patients with Osteoarthritis and Rheumatoid Arthritis but without Lupus was also calculated to determine the ability of the classifier to differentiate between Lupus and other diseases. Data were divided 1000 times into separate 2/3 training and 1/3 test data for evaluation of predictions. Finally, derivatives of thermogram curves were included in the models to determine whether they aided in prediction of disease status. Functional regression with thermogram as a

Hyperchromatic laser scanning cytometry

NASA Astrophysics Data System (ADS)

Tárnok, Attila; Mittag, Anja

2007-02-01

In the emerging fields of high-content and high-throughput single cell analysis for Systems Biology and Cytomics multi- and polychromatic analysis of biological specimens has become increasingly important. Combining different technologies and staining methods polychromatic analysis (i.e. using 8 or more fluorescent colors at a time) can be pushed forward to measure anything stainable in a cell, an approach termed hyperchromatic cytometry. For cytometric cell analysis microscope based Slide Based Cytometry (SBC) technologies are ideal as, unlike flow cytometry, they are non-consumptive, i.e. the analyzed sample is fixed on the slide. Based on the feature of relocation identical cells can be subsequently reanalyzed. In this manner data on the single cell level after manipulation steps can be collected. In this overview various components for hyperchromatic cytometry are demonstrated for a SBC instrument, the Laser Scanning Cytometer (Compucyte Corp., Cambridge, MA): 1) polychromatic cytometry, 2) iterative restaining (using the same fluorochrome for restaining and subsequent reanalysis), 3) differential photobleaching (differentiating fluorochromes by their different photostability), 4) photoactivation (activating fluorescent nanoparticles or photocaged dyes), and 5) photodestruction (destruction of FRET dyes). With the intelligent combination of several of these techniques hyperchromatic cytometry allows to quantify and analyze virtually all components of relevance on the identical cell. The combination of high-throughput and high-content SBC analysis with high-resolution confocal imaging allows clear verification of phenotypically distinct subpopulations of cells with structural information. The information gained per specimen is only limited by the number of available antibodies and by sterical hindrance.

Spectrum interrogation of fiber acoustic sensor based on self-fitting and differential method.

PubMed

Fu, Xin; Lu, Ping; Ni, Wenjun; Liao, Hao; Wang, Shun; Liu, Deming; Zhang, Jiangshan

2017-02-20

In this article, we propose an interrogation method of fiber acoustic sensor to recover the time-domain signal from the sensor spectrum. The optical spectrum of the sensor will show a ripple waveform when responding to acoustic signal due to the scanning process in a certain wavelength range. The reason behind this phenomenon is the dynamic variation of the sensor spectrum while the intensity of different wavelength is acquired at different time in a scanning period. The frequency components can be extracted from the ripple spectrum assisted by the wavelength scanning speed. The signal is able to be recovered by differential between the ripple spectrum and its self-fitted curve. The differential process can eliminate the interference caused by environmental perturbations such as temperature or refractive index (RI), etc. The proposed method is appropriate for fiber acoustic sensors based on gratings or interferometers. A long period grating (LPG) is adopted as an acoustic sensor head to prove the feasibility of the interrogation method in experiment. The ability to compensate the environmental fluctuations is also demonstrated.

CT scan

MedlinePlus

... this page: //medlineplus.gov/ency/article/003330.htm CT scan To use the sharing features on this page, please enable JavaScript. A computed tomography (CT) scan is an imaging method that uses x- ...

Precursor and Neutral Loss Scans in an RF Scanning Linear Quadrupole Ion Trap

NASA Astrophysics Data System (ADS)

Snyder, Dalton T.; Szalwinski, Lucas J.; Schrader, Robert L.; Pirro, Valentina; Hilger, Ryan; Cooks, R. Graham

2018-03-01

Methodology for performing precursor and neutral loss scans in an RF scanning linear quadrupole ion trap is described and compared to the unconventional ac frequency scan technique. In the RF scanning variant, precursor ions are mass selectively excited by a fixed frequency resonance excitation signal at low Mathieu q while the RF amplitude is ramped linearly to pass ions through the point of excitation such that the excited ion's m/z varies linearly with time. Ironically, a nonlinear ac frequency scan is still required for ejection of the product ions since their frequencies vary nonlinearly with the linearly varying RF amplitude. In the case of the precursor scan, the ejection frequency must be scanned so that it is fixed on a product ion m/z throughout the RF scan, whereas in the neutral loss scan, it must be scanned to maintain a constant mass offset from the excited precursor ions. Both simultaneous and sequential permutation scans are possible; only the former are demonstrated here. The scans described are performed on a variety of samples using different ionization sources: protonated amphetamine ions generated by nanoelectrospray ionization (nESI), explosives ionized by low-temperature plasma (LTP), and chemical warfare agent simulants sampled from a surface and analyzed with swab touch spray (TS). We lastly conclude that the ac frequency scan variant of these MS/MS scans is preferred due to electronic simplicity. In an accompanying manuscript, we thus describe the implementation of orthogonal double resonance precursor and neutral loss scans on the Mini 12 using constant RF voltage. [Figure not available: see fulltext.

Precision controlled atomic resolution scanning transmission electron microscopy using spiral scan pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai

Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with amore » constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.« less

Precision controlled atomic resolution scanning transmission electron microscopy using spiral scan pathways

NASA Astrophysics Data System (ADS)

Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai; Kalinin, Sergei V.; Jesse, Stephen; Unocic, Raymond R.

2017-03-01

Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with a constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.

Precision controlled atomic resolution scanning transmission electron microscopy using spiral scan pathways.

PubMed

Sang, Xiahan; Lupini, Andrew R; Ding, Jilai; Kalinin, Sergei V; Jesse, Stephen; Unocic, Raymond R

2017-03-08

Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. "Archimedean" spirals, with a constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.

Precision controlled atomic resolution scanning transmission electron microscopy using spiral scan pathways

DOE PAGES

Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai; ...

2017-03-08

Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with amore » constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.« less

CT Scans

MedlinePlus

... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

Bone scan

MedlinePlus

... scan is an imaging test used to diagnose bone diseases and find out how severe they are. How ... a 3-phase bone scan. To evaluate metastatic bone disease, images are taken only after the 3- to ...

Advantages and limitations of computed tomography scans for treatment planning of lung cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mira, J.G.; Potter, J.L.; Fullerton, G.D.

1982-09-01

Forty-five Chest computed tomography (CT) scans performed on patients with lung carcinoma (LC) were evaluated in an attempt to understand the pattern of intrathoracic tumor spread and the advantages and limitations this technique offers for treatment planning when compared to planning done by conventional X rays. The following findings can help treatment planning. (1) When regular X rays do not show location (i.e., hemithorax opacification), CT scan will show it in 68% of patients. If regular X rays show a well localized mass, unsuspected tumor extensions were disclosed in 78% of these patients. Hence, CT scans should be done inmore » all LC patients prior to treatment planning; (2) Mediastinal masses frequently spread anteriorly toward the sternum and posteriorly around the vertebral bodies toward the cord and costal pleura. This should be considered for radiotherapy boost techniques; (3) Lung masses spread in one third of cases toward the lateral costal pleura. Thus, the usual 1-2cm of safety margin around the LC are not sufficient in some cases; (4) Tumor size can appear much smaller in regular X rays than in CT scans. Hence, CT scans are necessary for accurate staging and evaluation of tumor response. Some CT scan limitations are: (1) Atelectasis blends with tumor in approximately half of the patients, thus obscuring tumor boundaries; (2) CT numbers and contrast enhancement did not help to differentiate between these two structures; and (3) Limited definition of CT scan prevents investigation of suspected microscopic spread around tumor masses.« less

Preliminary study on the differentiation between parapelvic cyst and hydronephrosis with non-calculous using only pre-contrast dual-energy spectral CT scans

PubMed Central

Han, Dong; Ma, Guangming; Wei, Lequn; Ren, Chenglong; Zhou, Jieli; Shen, Chen

2017-01-01

Objective: To investigate the value of using the quantitative parameters from only the pre-contrast dual-energy spectral CT imaging for distinguishing between parapelvic cyst and hydronephrosis with non-calculous (HNC). Methods: This retrospective study was approved by the institutional review board. 28 patients with parapelvic cyst and 24 patients with HNC who underwent standard pre-contrast and multiphase contrast-enhanced dual-energy spectral CT imaging were retrospectively identified. The parapelvic cyst and HNC were identified using the contrast-enhanced scans, and their CT number in the 70-keV monochromatic images, effective atomic number (Zeff), iodine concentration (IC) and water concentration in the pre-contrast images were measured. The slope of the spectral curve (λ) was calculated. The difference in the measurements between parapelvic cyst and HNC was statistically analyzed using SPSS® v. 19.0 (IBM Corp., New York, NY; formerly SPSS Inc., Chicago, IL) statistical software. Receiver-operating characteristic analysis was performed to assess the diagnostic performance. Results: The CT numbers in the 70-keV images, Zeff and IC values were statistically different between parapelvic cyst and HNC (all p < 0.05). The sensitivity, specificity and accuracy of these parameters for distinguishing between parapelvic cyst and HNC were 89.2%, 73.3% and 82.1%; 86.5%, 43.3% and 67.2%; 91.9%, 40.0% and 68.7%; and 64.9%, 73.3% and 83.6%, respectively, and the combined specificity was 92.9%. There was no statistical difference in λ between the two groups (p > 0.05). Conclusion: The quantitative parameters obtained in the pre-contrast dual-energy spectral CT imaging may be used to differentiate between parapelvic cyst and HNC. Advances in knowledge: The pre-contrast dual-energy spectral CT scans may be used to screen parapelvic cysts for patients who are asymptomatic, thereby avoiding contrast-enhanced CT or CT urography examination for these patients to reduce

Use of multidetector-row computed tomography scan to detect pannus formation in prosthetic mechanical aortic valves.

PubMed

Aladmawi, Mohamed A; Pragliola, Claudio; Vriz, Olga; Galzerano, Domenico

2017-04-01

Obstruction of a mechanical aortic valve by pannus formation at the subvalvular level is a major long-term complication of aortic valve replacement (AVR). In fact, pannus is sometime difficult to differentiate from patient-prosthesis mismatch or valve thrombosis. In most cases cine-angiography and echocardiography, either transthoracic or transesophageal, cannot correctly visualize the complication when the leaflets show a normal mobility. Recent technological refinements made this difficult diagnosis possible by ECG-gated computed tomography (CT) scan which shows adequate images in 90% of the cases and can differentiate pannus from fresh and organized thrombus.

False-positive iodine-131 whole-body scan findings in patients with differentiated thyroid carcinoma: report of 11 cases and review of the literature.

PubMed

Buton, Leckzinscka; Morel, Olivier; Gault, Patricia; Illouz, Frédéric; Rodien, Patrice; Rohmer, Vincent

2013-07-01

Iodine-131 (I-131) whole-body scan (WBS) plays an important role in the management of patients with differentiated thyroid carcinoma (DTC), to detect normal thyroid remnants and recurrent or metastatic disease. A focus of I-131 accumulation outside the thyroid bed and the areas of physiological uptake is strongly suggestive of a distant functioning metastasis. However, many false-positive I-131 WBS findings have been reported in the literature. We describe a series of 11 personal cases of patients with DTC, collected from 1992 to 2011, in whom diagnostic or post-treatment WBS showed false-positive retention of I-131 in various locations. False-positive accumulations of I-131 on WBS may be classified according to the underlying pathophysiological mechanisms: external and internal contaminations by body secretions, ectopic normal thyroid and gastric tissues, inflammatory and infectious diseases, benign and malignant tumors, cysts and effusions of serous cavities, thymic uptake, and other non classified causes. Clinicians must be aware of possible false-positive findings to avoid misinterpretations of the I-131 WBS, which could lead to inappropriate treatments. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Lumbar spine CT scan

MedlinePlus

CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... CT scans rapidly makes detailed pictures of the lower back. The test may be used to look for: ...

Differentiation of dental restorative materials combining energy-dispersive X-ray fluorescence spectroscopy and post-mortem CT.

PubMed

Merriam, Tim; Kaufmann, Rolf; Ebert, Lars; Figi, Renato; Erni, Rolf; Pauer, Robin; Sieberth, Till

2018-06-01

Today, post-mortem computed tomography (CT) is routinely used for forensic identification. Mobile energy-dispersive X-ray fluorescence (EDXRF) spectroscopy of a dentition is a method of identification that has the potential to be easier and cheaper than CT, although it cannot be used with every dentition. In challenging cases, combining both techniques could facilitate the process of identification and prove to be advantageous over chemical analyses. Nine dental restorative material brands were analyzed using EDXRF spectroscopy. Their differentiability was assessed by comparing each material's x-ray fluorescence spectrum and then comparing the spectra to previous research investigating differentiability in CT. To verify EDXRF's precision and accuracy, select dental specimens underwent comparative electron beam excited x-ray spectroscopy (EDS) scans, while the impact of the restorative surface area was studied by scanning a row of dental specimens with varying restorative surface areas (n = 10). EDXRF was able to differentiate all 36 possible pairs of dental filling materials; however, dual-energy CT was only able to differentiate 33 out of 36. The EDS scans showed correlating x-ray fluorescence peaks on the x-ray spectra compared to our EDXRF. In addition, the surface area showed no influence on the differentiability of the dental filling materials. EDXRF has the potential to facilitate corpse identification by differentiating and comparing restorative materials, providing more information compared to post-mortem CT alone. Despite not being able to explicitly identify a brand without a control sample or database, its fast and mobile use could accelerate daily routines or mass victim identification processes. To achieve this goal, further development of EDXRF scanners for this application and further studies evaluating the method within a specific routine need to be performed.

Small and cheap: accurate differential blood count with minimal sample volume by laser scanning cytometry (LSC)

NASA Astrophysics Data System (ADS)

Mittag, Anja; Lenz, Dominik; Smith, Paul J.; Pach, Susanne; Tarnok, Attila

2005-04-01

Aim: In patients, e.g. with congenital heart diseases, a differential blood count is needed for diagnosis. To this end by standard automatic analyzers 500 μl of blood is required from the patients. In case of newborns and infants this is a substantial volume, especially after operations associated with blood loss. Therefore, aim of this study was to develop a method to determine a differential blood picture with a substantially reduced specimen volume. Methods: To generate a differential blood picture 10 μl EDTA blood were mixed with 10 μl of a DRAQ5 solution (500μM, Biostatus) and 10 μl of an antibody mixture (CD45-FITC, CD14-PE, diluted with PBS). 20 μl of this cell suspension was filled into a Neubauer counting chamber. Due to the defined volume of the chamber it is possible to determine the cell count per volume. The trigger for leukocyte counting was set on DRAQ5 signal in order to be able to distinguish nucleated white blood cells from erythrocytes. Different leukocyte subsets could be distinguished due to the used fluorescence labeled antibodies. For erythrocyte counting cell suspension was diluted another 150 times. 20 μl of this dilution was analyzed in a microchamber by LSC with trigger set on forward scatter signal. Results: This method allows a substantial decrease of blood sample volume for generation of a differential blood picture (10 μl instead of 500μl). There was a high correlation between our method and the results of routine laboratory (r2=0.96, p<0.0001 n=40). For all parameters intra-assay variance was less than 7 %. Conclusions: In patients with low blood volume such as neonates and in critically ill infants every effort has to be taken to reduce the blood volume needed for diagnostics. With this method only 2% of standard sample volume is needed to generate a differential blood picture. Costs are below that of routine laboratory. We suggest this method to be established in paediatric cardiology for routine diagnostics and for

Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates.

PubMed

Zhang, Hao; Li, Xianqi; Chen, Yunmei; Park, Jewook; Li, An-Ping; Zhang, X-G

2017-01-01

We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a "rubber band" model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data.

Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates

PubMed Central

Zhang, Hao; Li, Xianqi; Park, Jewook; Li, An-Ping

2017-01-01

We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a “rubber band” model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data. PMID:29362664

SPECT/CT demonstrating 131I retention in Warthin tumor on thyroid cancer survey scan.

PubMed

Zhang, Yuyang; Minoshima, Satoshi

2013-09-01

A 48-year-old male patient of papillary thyroid cancer, status post-thyroidectomy and node dissection, was referred to (131)I scan prior to radioiodine treatment. The images showed 1 additional focus of (131)I uptake in the right upper neck outside of the thyroid bed. SPECT/CT demonstrated 2 separate foci of radioiodine uptake in the right parotid gland, instead of neck lymph nodes. Diagnostic CT showed 2 corresponding soft tissue nodules in the right parotid gland which were confirmed latter by fine-needle aspiration to be Warthin tumors. This case illustrates a pivotal role of SPECT/CT in differential diagnosis of abnormal neck uptake on (131)I thyroid cancer scan.

Correcting nonlinear drift distortion of scanning probe and scanning transmission electron microscopies from image pairs with orthogonal scan directions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ophus, Colin; Ciston, Jim; Nelson, Chris T.

Unwanted motion of the probe with respect to the sample is a ubiquitous problem in scanning probe and scanning transmission electron microscopies, causing both linear and nonlinear artifacts in experimental images. We have designed a procedure to correct these artifacts by using orthogonal scan pairs to align each measurement line-by-line along the slow scan direction, by fitting contrast variation along the lines. We demonstrate the accuracy of our algorithm on both synthetic and experimental data and provide an implementation of our method.

Correcting nonlinear drift distortion of scanning probe and scanning transmission electron microscopies from image pairs with orthogonal scan directions

DOE PAGES

Ophus, Colin; Ciston, Jim; Nelson, Chris T.

2015-12-10

Unwanted motion of the probe with respect to the sample is a ubiquitous problem in scanning probe and scanning transmission electron microscopies, causing both linear and nonlinear artifacts in experimental images. We have designed a procedure to correct these artifacts by using orthogonal scan pairs to align each measurement line-by-line along the slow scan direction, by fitting contrast variation along the lines. We demonstrate the accuracy of our algorithm on both synthetic and experimental data and provide an implementation of our method.

A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans

PubMed Central

Chen, Xu; Guo, Tengfei; Hou, Yubin; Zhang, Jing

2017-01-01

A new scan-head structure for the scanning tunneling microscope (STM) is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans) coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan). They are fixed at one end (called common end). A hollow tantalum shaft is coaxially housed in the XY-scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown. PMID:29270242

A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans.

PubMed

Chen, Xu; Guo, Tengfei; Hou, Yubin; Zhang, Jing; Meng, Wenjie; Lu, Qingyou

2017-01-01

A new scan-head structure for the scanning tunneling microscope (STM) is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans) coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan). They are fixed at one end (called common end). A hollow tantalum shaft is coaxially housed in the XY -scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown.

Special raster scanning for reduction of charging effects in scanning electron microscopy.

PubMed

Suzuki, Kazuhiko; Oho, Eisaku

2014-01-01

A special raster scanning (SRS) method for reduction of charging effects is developed for the field of SEM. Both a conventional fast scan (horizontal direction) and an unusual scan (vertical direction) are adopted for acquiring raw data consisting of many sub-images. These data are converted to a proper SEM image using digital image processing techniques. About sharpness of the image and reduction of charging effects, the SRS is compared with the conventional fast scan (with frame-averaging) and the conventional slow scan. Experimental results show the effectiveness of SRS images. By a successful combination of the proposed scanning method and low accelerating voltage (LV)-SEMs, it is expected that higher-quality SEM images can be more easily acquired by the considerable reduction of charging effects, while maintaining the resolution. © 2013 Wiley Periodicals, Inc.

Lidar arc scan uncertainty reduction through scanning geometry optimization

NASA Astrophysics Data System (ADS)

Wang, H.; Barthelmie, R. J.; Pryor, S. C.; Brown, G.

2015-10-01

Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation when arc scans are used for wind resource assessment.

Apparatus for controlling the scan width of a scanning laser beam

DOEpatents

Johnson, Gary W.

1996-01-01

Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board.

Crystallization kinetics and molecular mobility of an amorphous active pharmaceutical ingredient: A case study with Biclotymol.

PubMed

Schammé, Benjamin; Couvrat, Nicolas; Malpeli, Pascal; Delbreilh, Laurent; Dupray, Valérie; Dargent, Éric; Coquerel, Gérard

2015-07-25

The present case study focuses on the crystallization kinetics and molecular mobility of an amorphous mouth and throat drug namely Biclotymol, through differential scanning calorimetry (DSC), temperature resolved X-ray powder diffraction (TR-XRPD) and hot stage microscopy (HSM). Kinetics of crystallization above the glass transition through isothermal and non-isothermal cold crystallization were considered. Avrami model was used for isothermal crystallization process. Non-isothermal cold crystallization was investigated through Augis and Bennett model. Differences between crystallization processes have been ascribed to a site-saturated nucleation mechanism of the metastable form, confirmed by optical microscopy images. Regarding molecular mobility, a feature of molecular dynamics in glass-forming liquids as thermodynamic fragility index m was determined through calorimetric measurements. It turned out to be around m=100, describing Biclotymol as a fragile glass-former for Angell's classification. Relatively long-term stability of amorphous Biclotymol above Tg was analyzed indirectly by calorimetric monitoring to evaluate thermodynamic parameters and crystallization behavior of glassy Biclotymol. Within eight months of storage above Tg (T=Tg+2°C), amorphous Biclotymol does not show a strong inclination to crystallize and forms a relatively stable glass. This case study, involving a multidisciplinary approach, points out the importance of continuing looking for stability predictors. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying.

PubMed

Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas; Laitinen, Riikka

2015-12-03

In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS) revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a "spring and parachute" effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions) was observed when SLS was spray-dried with SVS (and LYS). In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

3D Printed "Starmix" Drug Loaded Dosage Forms for Paediatric Applications.

PubMed

Scoutaris, Nicolaos; Ross, Steven A; Douroumis, Dennis

2018-01-16

Three- dimensional (3D) printing has received significant attention as a manufacturing process for pharmaceutical dosage forms. In this study, we used Fusion Deposition Modelling (FDM) in order to print "candy - like" formulations by imitating Starmix® sweets to prepare paediatric medicines with enhanced palatability. Hot melt extrusion processing (HME) was coupled with FDM to prepare extruded filaments of indomethacin (IND), hypromellose acetate succinate (HPMCAS) and polyethylene glycol (PEG) formulations and subsequently feed them in the 3D printer. The shapes of the Starmix® objects were printed in the form of a heart, ring, bottle, ring, bear and lion. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Fourier Transform Infra-red Spectroscopy (FT-IR) and confocal Raman analysis were used to assess the drug - excipient interactions and the content uniformity. Physicochemical analysis showed the presence of molecularly dispersed IND in the printed tablets. In vivo taste masking evaluation demonstrated excellent masking of the drug bitterness. The printed forms were evaluated for drug dissolution and showed immediate IND release independently of the printed shape, within 60 min. 3D printing was used successfully to process drug loaded filaments for the development of paediatric printed tablets in the form of Starmix® designs.

Scan path entropy and arrow plots: capturing scanning behavior of multiple observers

PubMed Central

Hooge, Ignace; Camps, Guido

2013-01-01

Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures (1) “scan path entropy” to quantify gaze guidance and (2) the “arrow plot” to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50). The new measures were tested in an eye tracking study (48 observers, 39 advertisements). Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place. PMID:24399993

Apparatus for controlling the scan width of a scanning laser beam

DOEpatents

Johnson, G.W.

1996-10-22

Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board. 8 figs.

Radioisotope scanning of brain, liver, lung and bone with a note on tumour localizing agents

PubMed Central

Lavender, J. P.

1973-01-01

Radioisotopic scanning of brain, liver, lungs and the skeleton is briefly reviewed with a survey of recent developments of clinical significance. In brain scanning neoplasm detection rates of greater than 90% are claimed. The true figure is probably 70-80%. Autopsy data shows a number of false negatives, particularly with vascular lesions. Attempts to make scanning more specific in differentiating neoplasm from vascular lesions by rapid sequence blood flow studies are reviewed. In liver scanning by means of colloids again high success rate is claimed but small metastases are frequently missed and the false negative scan rate is probably quite high. Lung scanning still has its main place in investigating pulmonary embolic disease. Ventilation studies using Xenon 133 are useful, particularly combined with perfusion studies. The various radiopharmaceuticals for use in bone scanning are reviewed. The appearance of technetium labelled phosphate compounds will probably allow much wider use of total skeletal scanning. Research into tumour localizing agents continues, the most recent and interesting being Gallium citrate and labelled bleomycin. Neither agent is predictable however although Gallium may have a place in Hodgkins disease and bronchogenic neoplasm and both may have a place in the detection of cerebral tumours. ImagesFig. 1Fig. 2Fig. 3p452-bFig. 3bFig. 4Fig. 5Fig. 5bFig. 6Fig. 7Fig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 12c & 12dFig. 13Fig. 13 b,c,dFig. 14Fig. 14bFig. 15Fig. 15bFig. 16Fig. 17Fig. 18 PMID:4602127

Use of multidetector-row computed tomography scan to detect pannus formation in prosthetic mechanical aortic valves

PubMed Central

Aladmawi, Mohamed A.; Vriz, Olga; Galzerano, Domenico

2017-01-01

Obstruction of a mechanical aortic valve by pannus formation at the subvalvular level is a major long-term complication of aortic valve replacement (AVR). In fact, pannus is sometime difficult to differentiate from patient-prosthesis mismatch or valve thrombosis. In most cases cine-angiography and echocardiography, either transthoracic or transesophageal, cannot correctly visualize the complication when the leaflets show a normal mobility. Recent technological refinements made this difficult diagnosis possible by ECG-gated computed tomography (CT) scan which shows adequate images in 90% of the cases and can differentiate pannus from fresh and organized thrombus. PMID:28540078

Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments.

PubMed

Arias, Ana; Macorra, José C; Govindjee, Sanjay; Peters, Ove A

2018-04-01

The aim of this study was to assess differences in cyclic fatigue (CF) life of contemporary heat-treated nickel-titanium rotary instruments at room and body temperatures and to document corresponding phase transformations. Forty Hyflex EDM (H-EDM) files (Coltene, Cuyahoga Falls, OH [#25/.08, manufactured by electrical discharge machining]) and 40 TRUShape (TS) files (Dentsply Tulsa Dental Specialties, Tulsa, OK [#25/.06v, manufactured by grinding and shape setting]) were divided into 2 groups (n = 20) for CF resistance tests in a water bath either at room (22°C ± 0.5°C) or body temperature (37°C ± 0.5°C). Instruments were rotated in a simulated canal (angle = 60°, radius = 3 mm, and center of the curvature 5 mm from the tip) until fracture occurred. The motor was controlled by an electric circuit that was interrupted after instrument fracture. The mean half-life and beta and eta Weibull parameters were determined and compared. Two instruments of each brand were subjected to differential scanning calorimetry (DSC). While TS instruments lasted significantly longer at room temperature (mean life = 234.7 seconds; 95% confidence interval [CI], 209-263.6) than at body temperature (mean life = 83.2 seconds; 95% CI, 76-91.1), temperature did not affect H-EDM behavior (room temperature mean life = 725.4 seconds; 95% CI, 658.8-798.8 and body temperature mean life = 717.9 seconds; 95% CI, 636.8-809.3). H-EDM instruments significantly outlasted TS instruments at both temperatures. At body temperature, TS was predominantly austenitic, whereas H-EDM was martensitic or in R-phase. TS was in a mixed austenitic/martensitic phase at 22°C, whereas H-EDM was in the same state as at 37°C. H-EDM had a longer fatigue life than TS, which showed a marked decrease in fatigue life at body temperature; neither the life span nor the state of the microstructure in the DSC differed for H-EDM between room or body temperature. Copyright © 2017 American Association of

Conformational study of red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) by tryptophan fluorescence and differential scanning calorimetry.

PubMed

Yin, Shou-Wei; Tang, Chuan-He; Yang, Xiao-Quan; Wen, Qi-Biao

2011-01-12

Fluorescence and differential scanning calorimetry (DSC) were used to study changes in the conformation of red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) under various environmental conditions. The possible relationship between fluorescence data and DSC characteristics was also discussed. Tryptophan fluorescence and fluorescence quenching analyses indicated that the tryptophan residues in KPI, exhibiting multiple fluorophores with different accessibilities to acrylamide, are largely buried in the hydrophobic core of the protein matrix, with positively charged side chains close to at least some of the tryptophan residues. GdnHCl was more effective than urea and SDS in denaturing KPI. SDS and urea caused variable red shifts, 2-5 nm, in the emission λ(max), suggesting the conformational compactness of KPI. The result was further supported by DSC characteristics that a discernible endothermic peak was still detected up to 8 M urea or 30 mM SDS, also evidenced by the absence of any shift in emission maximum (λ(max)) at different pH conditions. Marked decreases in T(d) and enthalpy (ΔH) were observed at extreme alkaline and/or acidic pH, whereas the presence of NaCl resulted in higher T(d) and ΔH, along with greater cooperativity of the transition. Decreases in T(d) and ΔH were observed in the presence of protein perturbants, for example, SDS and urea, indicating partial denaturation and decrease in thermal stability. Dithiothreitol and N-ethylmaleimide have a slight effect on the thermal properties of KPI. Interestingly, a close linear relationship between the T(d) (or ΔH) and the λ(max) was observed for KPI in the presence of 0-6 M urea.

Influence of bending mode on the mechanical properties of nickel-titanium archwires and correlation to differential scanning calorimetry measurements.

PubMed

Brauchli, Lorenz M; Keller, Heidi; Senn, Christiane; Wichelhaus, Andrea

2011-05-01

Nickel-titanium orthodontic archwires are used with bonded appliances for initial leveling. However, precise bending of these archwires is difficult and can lead to changes within the crystal structure of the alloy, thus changing the mechanical properties unpredictably. The aim of this study was to evaluate different bending methods in relation to the subsequent mechanical characteristics of the alloy. The mechanical behaviors of 3 archwires (Copper NiTi 35°C [Ormco, Glendora, Calif], Neo Sentalloy F 80 [GAC International, Bohemia, NY], and Titanol Low Force [Forestadent, Pforzheim, Germany]) were investigated after heat-treatment in a dental furnace at 550-650°C, treatment with an electrical current (Memory-Maker, Forestadent), and cold forming. In addition, the change in A(f) temperature was registered by means of differential scanning calorimetry. Heat-treatment in the dental furnace as well as with the Memory-Maker led to widely varying force levels for each product. Cold forming resulted in similar or slightly reduced force levels when compared to the original state of the wires. A(f) temperatures were in general inversely proportional to force levels. Archwire shape can be modified by using either chair-side technique (Memory-Maker, cold forming) because the superelastic behavior of the archwires is not strongly affected. However it is important to know the specific changes in force levels induced for each individual archwire with heat-treatment. Cold forming resulted in more predictable forces for all products tested. Therefore, cold forming is recommended as a chair-side technique for the shaping of NiTi archwires. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

A comprehensive physicochemical, thermal, and spectroscopic characterization of zinc (II) chloride using X-ray diffraction, particle size distribution, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetric analysis, ultraviolet-visible, and Fourier transform-infrared spectroscopy

PubMed Central

Trivedi, Mahendra Kumar; Sethi, Kalyan Kumar; Panda, Parthasarathi; Jana, Snehasis

2017-01-01

Objective: Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. Materials and Methods: The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. Results: The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70–55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 (d10), 3.025 (d50), and 6.712 (d90) μm and average surface area of 2.71 m2/g. The span and relative span values were 5.849 μm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (ΔH) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ΔH of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed Tmax at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λmax), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn–Cl stretching. Conclusions: These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications. PMID:28405577

A comprehensive physicochemical, thermal, and spectroscopic characterization of zinc (II) chloride using X-ray diffraction, particle size distribution, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetric analysis, ultraviolet-visible, and Fourier transform-infrared spectroscopy.

PubMed

Trivedi, Mahendra Kumar; Sethi, Kalyan Kumar; Panda, Parthasarathi; Jana, Snehasis

2017-01-01

Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70-55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 ( d 10 ), 3.025 ( d 50 ), and 6.712 ( d 90 ) μm and average surface area of 2.71 m 2 /g. The span and relative span values were 5.849 μm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (ΔH) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ΔH of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed T max at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λ max ), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn-Cl stretching. These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications.

The use of Rheology Combined with Differential Scanning Calorimetry to Elucidate the Granulation Mechanism of an Immiscible Formulation During Continuous Twin-Screw Melt Granulation.

PubMed

Monteyne, Tinne; Heeze, Liza; Mortier, Severine Therese F C; Oldörp, Klaus; Cardinaels, Ruth; Nopens, Ingmar; Vervaet, Chris; Remon, Jean-Paul; De Beer, Thomas

2016-10-01

Twin screw hot melt granulation (TS HMG) is a valuable, but still unexplored alternative to continuous granulation of moisture sensitive drugs. However, knowledge of the material behavior during TS HMG is crucial to optimize the formulation, process and resulting granule properties. The aim of this study was to evaluate the agglomeration mechanism during TS HMG using a rheometer in combination with differential scanning calorimetry (DSC). An immiscible drug-binder formulation (caffeine-Soluplus(®)) was granulated via TS HMG in combination with thermal and rheological analysis (conventional and Rheoscope), granule characterization and Near Infrared chemical imaging (NIR-CI). A thin binder layer with restricted mobility was formed on the surface of the drug particles during granulation and is covered by a second layer with improved mobility when the Soluplus(®) concentration exceeded 15% (w/w). The formation of this second layer was facilitated at elevated granulation temperatures and resulted in smaller and more spherical granules. The combination of thermal and rheological analysis and NIR-CI images was advantageous to develop in-depth understanding of the agglomeration mechanism during continuous TS HMG and provided insight in the granule properties as function of process temperature and binder concentration.

A cryogenic multichannel electronically scanned pressure module

NASA Technical Reports Server (NTRS)

Shams, Qamar A.; Fox, Robert L.; Adcock, Edward E.; Kahng, Seun K.

1992-01-01

Consideration is given to a cryogenic multichannel electronically scanned pressure (ESP) module developed and tested over an extended temperature span from -184 to +50 C and a pressure range of 0 to 5 psig. The ESP module consists of 32 pressure sensor dice, four analog 8 differential-input multiplexers, and an amplifier circuit, all of which are packaged in a physical volume of 2 x 1 x 5/8 in with 32 pressure and two reference ports. Maximum nonrepeatability is measured at 0.21 percent of full-scale output. The ESP modules have performed consistently well over 15 times over the above temperature range and continue to work without any sign of degradation. These sensors are also immune to repeated thermal shock tests over a temperature change of 220 C/sec.

A scanning acoustic microscope discriminates cancer cells in fluid

NASA Astrophysics Data System (ADS)

Miura, Katsutoshi; Yamamoto, Seiji

2015-10-01

Scanning acoustic microscopy (SAM) discriminates lesions in sections by assessing the speed of sound (SOS) or attenuation of sound (AOS) through tissues within a few minutes without staining; however, its clinical use in cytological diagnosis is unknown. We applied a thin layer preparation method to observe benign and malignant effusions using SAM. Although SAM is inferior in detecting nuclear features than light microscopy, it can differentiate malignant from benign cells using the higher SOS and AOS values and large irregular cell clusters that are typical features of carcinomas. Moreover, each single malignant cell exhibits characteristic cytoplasmic features such as a large size, irregular borders and secretory or cytoskeletal content. By adjusting the observation range, malignant cells are differentiated from benign cells easily using SAM. Subtle changes in the functional and structural heterogeneity of tumour cells were pursuable with a different digital data of SAM. SAM can be a useful tool for screening malignant cells in effusions before light microscopic observation. Higher AOS values in malignant cells compared with those of benign cells support the feasibility of a novel sonodynamic therapy for malignant effusions.

Amorphous Sulfadoxine: A Physical Stability and Crystallization Kinetics Study.

PubMed

Aucamp, Marique; Milne, Marnus; Liebenberg, Wilna

2016-10-01

Poor aqueous solubility of drugs and the improvement thereof has always been a challenge for the pharmaceutical industry. With this, one of the focuses of the pharmaceutical research scientist involves investigating possible metastable forms of a given drug to be incorporated into solid dosage forms. The rationale being, the improved solubility offered by the metastable solid-state forms of drugs. Solubility remains a major challenge for formulation scientists, especially with antimicrobial agents where the emergence of resistance is directly dependent on the concentration and duration of the parasite exposed to the drug. Sulfadoxine-pyrimethamine combination therapies are still the recommended treatments for uncomplicated Plasmodium falciparum malaria. The aim of this study was to prepare an amorphous form of sulfadoxine and to investigate the stability and recrystallization behavior thereof. The amorphous form was prepared by the well-known quench cooling of the melt. The physico-chemical properties and stability of amorphous sulfadoxine were studied using hot-stage microscopy (HSM), scanning electron microscopy (SEM), x-ray powder diffractometry (XRPD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), as well as microcalorimetry. The recrystallization kinetics were studied isothermally by applying the Johnson-Mehl-Avrami model and non-isothermally by applying the Kissinger model. The physical stabilization of the amorphous form was investigated using physical mixtures of amorphous sulfadoxine with polyvinylpyrrolidone-25 (PVP-25). It was proved that sulfadoxine is a good glass former with relative high physical stability; however, water acts as a strong plasticizer for amorphous sulfadoxine, detrimentally affecting the stability during exposure to high moisture conditions.

Rapid-scan EPR imaging.

PubMed

Eaton, Sandra S; Shi, Yilin; Woodcock, Lukas; Buchanan, Laura A; McPeak, Joseph; Quine, Richard W; Rinard, George A; Epel, Boris; Halpern, Howard J; Eaton, Gareth R

2017-07-01

In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250MHz. Copyright © 2017 Elsevier Inc. All rights reserved.

Cervical spine CT scan

MedlinePlus

... cervical spine; Computed tomography scan of cervical spine; CT scan of cervical spine; Neck CT scan ... table that slides into the center of the CT scanner. Once you are inside the scanner, the ...

Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope.

PubMed

Nazin, G V; Wu, S W; Ho, W

2005-06-21

The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends.

Infrared zone-scanning system.

PubMed

Belousov, Aleksandr; Popov, Gennady

2006-03-20

Challenges encountered in designing an infrared viewing optical system that uses a small linear detector array based on a zone-scanning approach are discussed. Scanning is performed by a rotating refractive polygon prism with tilted facets, which, along with high-speed line scanning, makes the scanning gear as simple as possible. A method of calculation of a practical optical system to compensate for aberrations during prism rotation is described.

MutScan: fast detection and visualization of target mutations by scanning FASTQ data.

PubMed

Chen, Shifu; Huang, Tanxiao; Wen, Tiexiang; Li, Hong; Xu, Mingyan; Gu, Jia

2018-01-22

Some types of clinical genetic tests, such as cancer testing using circulating tumor DNA (ctDNA), require sensitive detection of known target mutations. However, conventional next-generation sequencing (NGS) data analysis pipelines typically involve different steps of filtering, which may cause miss-detection of key mutations with low frequencies. Variant validation is also indicated for key mutations detected by bioinformatics pipelines. Typically, this process can be executed using alignment visualization tools such as IGV or GenomeBrowse. However, these tools are too heavy and therefore unsuitable for validating mutations in ultra-deep sequencing data. We developed MutScan to address problems of sensitive detection and efficient validation for target mutations. MutScan involves highly optimized string-searching algorithms, which can scan input FASTQ files to grab all reads that support target mutations. The collected supporting reads for each target mutation will be piled up and visualized using web technologies such as HTML and JavaScript. Algorithms such as rolling hash and bloom filter are applied to accelerate scanning and make MutScan applicable to detect or visualize target mutations in a very fast way. MutScan is a tool for the detection and visualization of target mutations by only scanning FASTQ raw data directly. Compared to conventional pipelines, this offers a very high performance, executing about 20 times faster, and offering maximal sensitivity since it can grab mutations with even one single supporting read. MutScan visualizes detected mutations by generating interactive pile-ups using web technologies. These can serve to validate target mutations, thus avoiding false positives. Furthermore, MutScan can visualize all mutation records in a VCF file to HTML pages for cloud-friendly VCF validation. MutScan is an open source tool available at GitHub: https://github.com/OpenGene/MutScan.

Infrared spectroscopy of molecular submonolayers on surfaces by infrared scanning tunneling microscopy: tetramantane on Au111.

PubMed

Pechenezhskiy, Ivan V; Hong, Xiaoping; Nguyen, Giang D; Dahl, Jeremy E P; Carlson, Robert M K; Wang, Feng; Crommie, Michael F

2013-09-20

We have developed a new scanning-tunneling-microscopy-based spectroscopy technique to characterize infrared (IR) absorption of submonolayers of molecules on conducting crystals. The technique employs a scanning tunneling microscope as a precise detector to measure the expansion of a molecule-decorated crystal that is irradiated by IR light from a tunable laser source. Using this technique, we obtain the IR absorption spectra of [121]tetramantane and [123]tetramantane on Au(111). Significant differences between the IR spectra for these two isomers show the power of this new technique to differentiate chemical structures even when single-molecule-resolved scanning tunneling microscopy (STM) images look quite similar. Furthermore, the new technique was found to yield significantly better spectral resolution than STM-based inelastic electron tunneling spectroscopy, and to allow determination of optical absorption cross sections. Compared to IR spectroscopy of bulk tetramantane powders, infrared scanning tunneling microscopy (IRSTM) spectra reveal narrower and blueshifted vibrational peaks for an ordered tetramantane adlayer. Differences between bulk and surface tetramantane vibrational spectra are explained via molecule-molecule interactions.

Lung PET scan

MedlinePlus

... PET - chest; PET - lung; PET - tumor imaging; PET/CT - lung; Solitary pulmonary nodule - PET ... minutes. PET scans are performed along with a CT scan. This is because the combined information from ...

Lidar arc scan uncertainty reduction through scanning geometry optimization

NASA Astrophysics Data System (ADS)

Wang, Hui; Barthelmie, Rebecca J.; Pryor, Sara C.; Brown, Gareth.

2016-04-01

Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.

[Creation and Evaluation of Educational Programs for Additional Delayed Scan of FDG-PET/CT].

PubMed

Wada, Ryota; Kamiya, Takashi; Fujino, Kouichi; Ueda, Junpei; Isohashi, Kayako; Tatsumi, Mitsuaki; Hatazawa, Jun

Generally, FDG-PET/CT image is acquired at the 60th minute after tracer administration. Depending on the clinical case, additional delayed scans may be useful. However, it is difficult to judge whether additional delayed scan is useful or not. The purposes of this study were creation and evaluation of educational programs to help radiological technologists to decide the usefulness of additional delayed scan of FDG-PET/CT. Educational programs consisted of the instructional materials and the judgment test of clinical cases. The instructional materials provided the valuable findings for differentiation between uptake in the wall of the colon and colon content, distinction between uptake in the lymph node and urinary tract, and evaluation of malignancy. The judgment test of clinical cases consisted of 10 cases selected by a nuclear medicine physician (for 5 of that cases additional delayed scan was decided to be useful). Five experienced technologists and five inexperienced technologists scored the volubility of additional delayed scan pre- and post-training using the instructional materials (the full marks of score is 5). After the educational programs using the instructional materials, the score was improved with the significant difference in both experienced (pre: 3.6±1.4, post: 4.0±1.2) and inexperienced (pre: 2.8±1.5, post: 3.7±1.5) groups (p<0.05). According to the educational programs, technologist might be able to decide whether the additional delayed scan is useful or not. The successful results of this study may improve the interpretation or reduce the total exposure dose of the PET/CT scan.

RBC nuclear scan

MedlinePlus

... page: //medlineplus.gov/ency/article/003835.htm RBC nuclear scan To use the sharing features on this page, please enable JavaScript. An RBC nuclear scan uses small amounts of radioactive material to ...

Heart CT scan

MedlinePlus

... Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agatston ... table that slides into the center of the CT scanner. You will lie on your back with ...

DepositScan, a Scanning Program to Measure Spray Deposition Distributions

USDA-ARS?s Scientific Manuscript database

DepositScan, a scanning program was developed to quickly measure spray deposit distributions on water sensitive papers or Kromekote cards which are widely used for determinations of pesticide spray deposition quality on target areas. The program is installed in a portable computer and works with a ...

Laser Scanning In Inspection

NASA Astrophysics Data System (ADS)

West, Patricia; Baker, Lionel R.

1989-03-01

This paper is a review of the applications of laser scanning in inspection. The reasons for the choice of a laser in flying spot scanning and the optical properties of a laser beam which are of value in a scanning instrument will be given. The many methods of scanning laser beams in both one and two dimensions will be described. The use of one dimensional laser scanners for automatic surface inspection for transmitting and reflective products will be covered in detail, with particular emphasis on light collection techniques. On-line inspection applications which will be mentioned include: photographic film web, metal strip products, paper web, glass sheet, car body paint surfaces and internal cylinder bores. Two dimensional laser scanning is employed in applications where increased resolution, increased depth of focus, and better contrast are required compared with conventional vidicon TV or solid state array cameras. Such examples as special microscope laser scanning systems and a TV compatible system for use in restricted areas of a nuclear reactor will be described. The technical and economic benefits and limitations of laser scanning video systems will be compared with conventional TV and CCD array devices.

Fundamental radiological and geometric performance of two types of proton beam modulated discrete scanning systems.

PubMed

Farr, J B; Dessy, F; De Wilde, O; Bietzer, O; Schönenberg, D

2013-07-01

The purpose of this investigation was to compare and contrast the measured fundamental properties of two new types of modulated proton scanning systems. This provides a basis for clinical expectations based on the scanned beam quality and a benchmark for computational models. Because the relatively small beam and fast scanning gave challenges to the characterization, a secondary purpose was to develop and apply new approaches where necessary to do so. The following performances of the proton scanning systems were investigated: beamlet alignment, static in-air beamlet size and shape, scanned in-air penumbra, scanned fluence map accuracy, geometric alignment of scanning system to isocenter, maximum field size, lateral and longitudinal field uniformity of a 1 l cubic uniform field, output stability over time, gantry angle invariance, monitoring system linearity, and reproducibility. A range of detectors was used: film, ionization chambers, lateral multielement and longitudinal multilayer ionization chambers, and a scintillation screen combined with a digital video camera. Characterization of the scanned fluence maps was performed with a software analysis tool. The resulting measurements and analysis indicated that the two types of delivery systems performed within specification for those aspects investigated. The significant differences were observed between the two types of scanning systems where one type exhibits a smaller spot size and associated penumbra than the other. The differential is minimum at maximum energy and increases inversely with decreasing energy. Additionally, the large spot system showed an increase in dose precision to a static target with layer rescanning whereas the small spot system did not. The measured results from the two types of modulated scanning types of system were consistent with their designs under the conditions tested. The most significant difference between the types of system was their proton spot size and associated resolution

Clinical experience with recombinant human thyroid-stimulating hormone (rhTSH): whole-body scanning with iodine-131.

PubMed

Reiners, C; Luster, M; Lassmann, M

1999-01-01

Whole-body scanning (WBS) with iodine-131 (I-131) is currently used together with serum thyroglobulin (Tg) measurement in the diagnostic follow-up of well-differentiated thyroid carcinoma. One of the main disadvantages of I-131 WBS is its requirement of repeated weeks-long withdrawal of thyroid hormone suppression therapy (THST) to raise endogenous thyroid-stimulating hormone (TSH) production. This results in hypothyroidism and associated abnormalities, discomfort and morbidity. Recently, however, a series of multicentre clinical studies established the efficacy, safety, non-antigenicity, and quality of life benefits of recombinant human TSH (rhTSH, Thyrogen, thyrotropin alfa, Genzyme Corporation, Cambridge, MA, USA) in promoting radioiodine uptake and permitting sensitive I-131 WBS in patients on THST after initial therapy of well-differentiated thyroid cancer. Thus in everyday practice, rhTSH administration may in many cases supersede THST withdrawal as a preparative method for I-131 imaging. With the use of rhTSH, as whenever I-131 WBS is performed, useful and accurate imaging requires meticulous attention to good scanning practices. These include use of appropriate equipment, proper timing, sufficient scanning time, vigilance against artifacts and iodine contamination, and consideration of additional imaging in the case of ambiguous 48-hour scans. Whole-body retention of I-131 is approximately 50% greater during hypothyroidism after THST withdrawal than during euthyroidism on THST and rhTSH. Therefore, it is important to use an adequate diagnostic activity of > or =4 mCi (148 MBq) to compensate for the faster radioiodine clearance in the euthyroid state permitted by rhTSH administration. Ongoing dosimetric research eventually may provide more specific guidance regarding radioiodine activities for diagnostic, and, particularly, therapeutic purposes, with the use of rhTSH.

Lidar arc scan uncertainty reduction through scanning geometry optimization

DOE PAGES

Wang, Hui; Barthelmie, Rebecca J.; Pryor, Sara C.; ...

2016-04-13

Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annualmore » energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30% of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. As a result, large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.« less

Lidar arc scan uncertainty reduction through scanning geometry optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hui; Barthelmie, Rebecca J.; Pryor, Sara C.

Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annualmore » energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30% of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. As a result, large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.« less

Scanning Seismic Intrusion Detector

NASA Technical Reports Server (NTRS)

Lee, R. D.

1982-01-01

Scanning seismic intrusion detector employs array of automatically or manually scanned sensors to determine approximate location of intruder. Automatic-scanning feature enables one operator to tend system of many sensors. Typical sensors used with new system are moving-coil seismic pickups. Detector finds uses in industrial security systems.

Diagnostic performance of shear wave elastography of the breast according to scanning orientation.

PubMed

Kim, Solip; Choi, SeonHyeong; Choi, Yoonjung; Kook, Shin-Ho; Park, Hee Jin; Chung, Eun Chul

2014-10-01

To evaluate the influence of the scanning orientation on diagnostic performance measured by the mean elasticity, maximum elasticity, and fat-to-lesion elasticity ratio on ultrasound-based shear wave elastography in differentiating breast cancers from benign lesions. In this study, a total of 260 breast masses from 235 consecutive patients were observed from March 2012 to November 2012. For each lesion, the mean elasticity value, maximum elasticity value, and fat-to-lesion ratio were measured along two orthogonal directions, and all values were compared with pathologic results. There were 59 malignant and 201 benign lesions. Malignant masses showed higher mean elasticity, maximum elasticity, and fat-to-lesion ratio values than benign lesions (P < .0001). The areas under the receiver operating characteristic curves were as follows: average mean elasticity on both views, 0.870; mean elasticity on the transverse view, 0.866; maximum elasticity on both views, 0.865; maximum elasticity on the transverse view, 0.864; mean elasticity on the longitudinal view, 0.849; fat-to-lesion ratio on both views, 0.849; maximum elasticity on the longitudinal view, 0.845; fat-to-lesion ratio on the transverse view, 0.841; and fat-to-lesion ratio on the longitudinal view, 0.814. Intraclass correlation coefficients for agreement between the scanning directions were as follows: mean elasticity, 0.852; maximum elasticity, 0.842; fat-to-lesion ratio, 0.746, for masses; and mean elasticity, 0.392, for anterior mammary fat. Mean elasticity, maximum elasticity, and fat-to-lesion elasticity ratio values were helpful in differentiating benign and malignant breast masses. The scanning orientation did not significantly affect the diagnostic performance of shear wave elastography for breast masses. © 2014 by the American Institute of Ultrasound in Medicine.

Investigation of Energy-Dispersive X-ray Computed Tomography System with CdTe Scan Detector and Comparing-Differentiator and Its Application to Gadolinium K-Edge Imaging

NASA Astrophysics Data System (ADS)

Chiba, Hiraku; Sato, Yuichi; Sato, Eiichi; Maeda, Tomoko; Matsushita, Ryo; Yanbe, Yutaka; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2012-10-01

An energy-dispersive (ED) X-ray computed tomography (CT) system is useful for carrying out monochromatic imaging by selecting optimal energy photons. CT is performed by repeated linear scans and rotations of an object. X-ray photons from the object are detected by the cadmium telluride (CdTe) detector, and event pulses of X-ray photons are produced using charge-sensitive and shaping amplifiers. The lower photon energy is determined by a comparator, and the maximum photon energy of 70 keV corresponds to the tube voltage. Logical pulses from the comparator are counted by a counter card through a differentiator to reduce pulse width and rise time. In the ED-CT system, tube voltage and current were 70 kV and 0.30 mA, respectively, and X-ray intensity was 18.2 µGy/s at 1.0 m from the source at a tube voltage of 70 kV. Demonstration of gadolinium K-edge CT for cancer diagnosis was carried out by selecting photons with energies ranging from 50.4 to 70 keV, and photon-count energy subtraction imaging from 30 to 50.3 keV was also performed.

Using terrestrial laser scanning for differential measurement of interannual rock glacier movement in the Argentine Dry Andes

NASA Astrophysics Data System (ADS)

Kane, Renato R.

Argentina has recently implemented laws to protect glaciers and buried ice in the Andes to improve the sustainability of scarce, long-term water resources. Therefore, all glaciers and buried ice terrains must be located and avoided in any commercial alterations of the landscape. Buried ice in this remote and often dangerous terrain typically is located via the use of remote-sensing techniques. This thesis applies one such technique, Light Detection and Ranging (LiDAR) in the form of Terrestrial Laser Scanning (TLS), to detect rock glacier movement that is indicative of flowing, buried ice not visible in near surface excavations. TLS surveys were completed at two locales, Los Azules and El Altar, in both AD 2013 and AD 2014 on landscapes where buried ice is suspected to have produced the current surface forms. Multiple TLS scans were co-registered with the use of benchmarks, both between scans and between years, which introduced quantifiable positional errors. Digital Elevation Models (DEMs) were derived from the point cloud data by standardizing the spacing of the points in the horizontal direction, creating 0.1 m by 0.1 m cells with elevation as the cell value. The DEMs for each year were subtracted from each other to yield a change in elevation. The surface roughness of the rock glaciers (vertical variability within each cell) was empirically determined and evaluated as a threshold for results. Both sites showed sub-decimeter interannual movements, and the direction of their movement is typical of forms with buried ice. The results of the study were validated using independent GPS data showing annual movement rates. Despite the downslope movement of these rock glaciers, the volume of ice contained within them remains unclear, and further study is required to assess the volume of water contained.

Instrument scanning and controlling: Using eye movement data to understand pilot behavior and strategies

NASA Technical Reports Server (NTRS)

Dick, A. O.

1980-01-01

Eye movement data and other parameters including instrument readings, aircraft state and position variables, and control maneuvers were recorded while pilots flew ILS simulations in a B 737. The experiment itself employed seven airline pilots, each of whom flew approximately 40 approach/landing sequences. The simulator was equipped with a night visual scene but the scene was fogged out down to approximately 60 meters (200 ft). The instrument scanning appeared to follow aircraft parameters not physical position of instruments. One important implication of the results is: pilots look for categories or packets of information. Control inputs were tabulated according to throttle, wheel position, column, and pitch trim changes. Three seconds of eye movements before and after the control input were then obtained. Analysis of the eye movement data for the controlling periods showed clear patterns. The results suggest a set of miniscan patterns which are used according to the specific details of the situation. A model is developed which integrates scanning and controlling. Differentiations are made between monitoring and controlling scans.

Use of scanning calorimetry and microrespiration to determine effects of Bt toxin doses on Pandemis leafroller (Lepidoptera: Tortricidae) metabolism

USDA-ARS?s Scientific Manuscript database

Differential scanning calorimetry and microrespiration were used to determine the effects of the biopesticide, Bt toxin, on the metabolism of infected Pandemis leafroller, Pandemis purusana (Kearfott). The metabolic heat rate, CO2 evolution, O2 consumption of 2nd and 3rd instars following a 2 h expo...

Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope

PubMed Central

Nazin, G. V.; Wu, S. W.; Ho, W.

2005-01-01

The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends. PMID:15956189

Excitation-scanning hyperspectral imaging microscope

PubMed Central

Favreau, Peter F.; Hernandez, Clarissa; Heaster, Tiffany; Alvarez, Diego F.; Rich, Thomas C.; Prabhat, Prashant; Leavesley, Silas J.

2014-01-01

Abstract. Hyperspectral imaging is a versatile tool that has recently been applied to a variety of biomedical applications, notably live-cell and whole-tissue signaling. Traditional hyperspectral imaging approaches filter the fluorescence emission over a broad wavelength range while exciting at a single band. However, these emission-scanning approaches have shown reduced sensitivity due to light attenuation from spectral filtering. Consequently, emission scanning has limited applicability for time-sensitive studies and photosensitive applications. In this work, we have developed an excitation-scanning hyperspectral imaging microscope that overcomes these limitations by providing high transmission with short acquisition times. This is achieved by filtering the fluorescence excitation rather than the emission. We tested the efficacy of the excitation-scanning microscope in a side-by-side comparison with emission scanning for detection of green fluorescent protein (GFP)-expressing endothelial cells in highly autofluorescent lung tissue. Excitation scanning provided higher signal-to-noise characteristics, as well as shorter acquisition times (300  ms/wavelength band with excitation scanning versus 3  s/wavelength band with emission scanning). Excitation scanning also provided higher delineation of nuclear and cell borders, and increased identification of GFP regions in highly autofluorescent tissue. These results demonstrate excitation scanning has utility in a wide range of time-dependent and photosensitive applications. PMID:24727909

Excitation-scanning hyperspectral imaging microscope.

PubMed

Favreau, Peter F; Hernandez, Clarissa; Heaster, Tiffany; Alvarez, Diego F; Rich, Thomas C; Prabhat, Prashant; Leavesley, Silas J

2014-04-01

Hyperspectral imaging is a versatile tool that has recently been applied to a variety of biomedical applications, notably live-cell and whole-tissue signaling. Traditional hyperspectral imaging approaches filter the fluorescence emission over a broad wavelength range while exciting at a single band. However, these emission-scanning approaches have shown reduced sensitivity due to light attenuation from spectral filtering. Consequently, emission scanning has limited applicability for time-sensitive studies and photosensitive applications. In this work, we have developed an excitation-scanning hyperspectral imaging microscope that overcomes these limitations by providing high transmission with short acquisition times. This is achieved by filtering the fluorescence excitation rather than the emission. We tested the efficacy of the excitation-scanning microscope in a side-by-side comparison with emission scanning for detection of green fluorescent protein (GFP)-expressing endothelial cells in highly autofluorescent lung tissue. Excitation scanning provided higher signal-to-noise characteristics, as well as shorter acquisition times (300  ms/wavelength band with excitation scanning versus 3  s/wavelength band with emission scanning). Excitation scanning also provided higher delineation of nuclear and cell borders, and increased identification of GFP regions in highly autofluorescent tissue. These results demonstrate excitation scanning has utility in a wide range of time-dependent and photosensitive applications.

Cost-effectiveness and accuracy of the tests used in the differential diagnosis of Cushing's syndrome.

PubMed

Puig, J; Wägner, A; Caballero, A; Rodríguez-Espinosa, J; Webb, S M

1999-01-01

Establish the minimal biochemical and radiological examinations necessary and their cost-effectiveness to accurately diagnose the etiology of Cushing's syndrome (CS). In 71 patients with CS followed between 1982 and 1997 biochemical studies (basal ACTH, 8 mg dexamethasone suppression test-HDST-, metyrapone stimulation test-MST-, or inferior petrosal sinus catheterization-IPSC-) and radiological investigations (abdominal CT scan, pituitary CT scan or MRI) were performed. Once pathology confirmed the diagnosis (48 pituitary Cushing's disease-CD, 17 adrenal neoplasms, 2 bilateral macronodular hyperplasia-BMH-, and 4 ectopic ACTH syndrome-ES-), the sensitivity, specificity, positive and negative predictive value of the different studies was calculated to establish the most accurate and cost-effective diagnostic protocol. In ACTH-independent CS (ACTH < or = 9 pg/ml; normal 9 to 54) a unilateral tumor was identified on abdominal CT scanning in 17, and BMH in 1; the other BMH had detectable ACTH (43.2 pg/ml). In ACTH-dependent CS, ACTH was > 9 pg/ml and IPSC (performed in 22) correctly identified 20 patients with CD and differentiated them from 2 with an ES (100% specificity and sensitivity). Pituitary MRI or CT did not disclose an adenoma in 41.7% of patients with CD, and was reported to exhibit a microadenoma in 2 of the 4 patients with ES. HDST and MST were of no additional use in the differentiation between CD and ES. Once CS is diagnosed low ACTH and an abdominal CT scan correctly identified all patients of adrenal origin. In ACTH-dependent CS IPSC was the best predictive test to differentiate CD from ES. BMH may behave as ACTH-dependent or independent. The other biochemical and radiological studies performed are not cost-effective and may even be misleading, and should not be routinely performed.

Machine learning for the automatic localisation of foetal body parts in cine-MRI scans

NASA Astrophysics Data System (ADS)

Bowles, Christopher; Nowlan, Niamh C.; Hayat, Tayyib T. A.; Malamateniou, Christina; Rutherford, Mary; Hajnal, Joseph V.; Rueckert, Daniel; Kainz, Bernhard

2015-03-01

Being able to automate the location of individual foetal body parts has the potential to dramatically reduce the work required to analyse time resolved foetal Magnetic Resonance Imaging (cine-MRI) scans, for example, for use in the automatic evaluation of the foetal development. Currently, manual preprocessing of every scan is required to locate body parts before analysis can be performed, leading to a significant time overhead. With the volume of scans becoming available set to increase as cine-MRI scans become more prevalent in clinical practice, this stage of manual preprocessing is a bottleneck, limiting the data available for further analysis. Any tools which can automate this process will therefore save many hours of research time and increase the rate of new discoveries in what is a key area in understanding early human development. Here we present a series of techniques which can be applied to foetal cine-MRI scans in order to first locate and then differentiate between individual body parts. A novel approach to maternal movement suppression and segmentation using Fourier transforms is put forward as a preprocessing step, allowing for easy extraction of short movements of individual foetal body parts via the clustering of optical flow vector fields. These body part movements are compared to a labelled database and probabilistically classified before being spatially and temporally combined to give a final estimate for the location of each body part.

Slow Scan Telemedicine

NASA Technical Reports Server (NTRS)

1984-01-01

Originally developed under contract for NASA by Ball Bros. Research Corporation for acquiring visual information from lunar and planetary spacecraft, system uses standard closed circuit camera connected to a device called a scan converter, which slows the stream of images to match an audio circuit, such as a telephone line. Transmitted to its destination, the image is reconverted by another scan converter and displayed on a monitor. In addition to assist scans, technique allows transmission of x-rays, nuclear scans, ultrasonic imagery, thermograms, electrocardiograms or live views of patient. Also allows conferencing and consultation among medical centers, general practitioners, specialists and disease control centers. Commercialized by Colorado Video, Inc., major employment is in business and industry for teleconferencing, cable TV news, transmission of scientific/engineering data, security, information retrieval, insurance claim adjustment, instructional programs, and remote viewing of advertising layouts, real estate, construction sites or products.

High-throughput microfluidic line scan imaging for cytological characterization

NASA Astrophysics Data System (ADS)

Hutcheson, Joshua A.; Powless, Amy J.; Majid, Aneeka A.; Claycomb, Adair; Fritsch, Ingrid; Balachandran, Kartik; Muldoon, Timothy J.

2015-03-01

Imaging cells in a microfluidic chamber with an area scan camera is difficult due to motion blur and data loss during frame readout causing discontinuity of data acquisition as cells move at relatively high speeds through the chamber. We have developed a method to continuously acquire high-resolution images of cells in motion through a microfluidics chamber using a high-speed line scan camera. The sensor acquires images in a line-by-line fashion in order to continuously image moving objects without motion blur. The optical setup comprises an epi-illuminated microscope with a 40X oil immersion, 1.4 NA objective and a 150 mm tube lens focused on a microfluidic channel. Samples containing suspended cells fluorescently stained with 0.01% (w/v) proflavine in saline are introduced into the microfluidics chamber via a syringe pump; illumination is provided by a blue LED (455 nm). Images were taken of samples at the focal plane using an ELiiXA+ 8k/4k monochrome line-scan camera at a line rate of up to 40 kHz. The system's line rate and fluid velocity are tightly controlled to reduce image distortion and are validated using fluorescent microspheres. Image acquisition was controlled via MATLAB's Image Acquisition toolbox. Data sets comprise discrete images of every detectable cell which may be subsequently mined for morphological statistics and definable features by a custom texture analysis algorithm. This high-throughput screening method, comparable to cell counting by flow cytometry, provided efficient examination including counting, classification, and differentiation of saliva, blood, and cultured human cancer cells.

Non-linear optical measurements using a scanned, Bessel beam

NASA Astrophysics Data System (ADS)

Collier, Bradley B.; Awasthi, Samir; Lieu, Deborah K.; Chan, James W.

2015-03-01

Oftentimes cells are removed from the body for disease diagnosis or cellular research. This typically requires fluorescent labeling followed by sorting with a flow cytometer; however, possible disruption of cellular function or even cell death due to the presence of the label can occur. This may be acceptable for ex vivo applications, but as cells are more frequently moving from the lab to the body, label-free methods of cell sorting are needed to eliminate these issues. This is especially true of the growing field of stem cell research where specialized cells are needed for treatments. Because differentiation processes are not completely efficient, cells must be sorted to eliminate any unwanted cells (i.e. un-differentiated or differentiated into an unwanted cell type). In order to perform label-free measurements, non-linear optics (NLO) have been increasingly utilized for single cell analysis because of their ability to not disrupt cellular function. An optical system was developed for the measurement of NLO in a microfluidic channel similar to a flow cytometer. In order to improve the excitation efficiency of NLO, a scanned Bessel beam was utilized to create a light-sheet across the channel. The system was tested by monitoring twophoton fluorescence from polystyrene microbeads of different sizes. Fluorescence intensity obtained from light-sheet measurements were significantly greater than measurements made using a static Gaussian beam. In addition, the increase in intensity from larger sized beads was more evident for the light-sheet system.

Differential scanning calorimetry study and computer modeling of β ⇒ α phase transformation in a Ti-6Al-4V alloy

NASA Astrophysics Data System (ADS)

Malinov, S.; Guo, Z.; Sha, W.; Wilson, A.

2001-04-01

The relationship between heat-treatment parameters and microstructure in titanium alloys has so far been mainly studied empirically, using characterization techniques such as microscopy. Calculation and modeling of the kinetics of phase transformation have not yet been widely used for these alloys. Differential scanning calorimetry (DSC) has been widely used for the study of a variety of phase transformations. There has been much work done on the calculation and modeling of the kinetics of phase transformations for different systems based on the results from DSC study. In the present work, the kinetics of the β ⇒ α transformation in a Ti-6Al-4V titanium alloy were studied using DSC, at continuous cooling conditions with constant cooling rates of 5 °C, 10 °C, 20 °C, 30 °C, 40 °C, and 50 °C/min. The results from calorimetry were then used to trace and model the transformation kinetics in continuous cooling conditions. Based on suitably interpreted DSC results, continuous cooling-transformation (CCT) diagrams were calculated with lines of isotransformed fraction. The kinetics of transformation were modeled using the Johnson-Mehl-Avrami (JMA) theory and by applying the “concept of additivity.” The JMA kinetic parameters were derived. Good agreement between the calculated and experimental transformed fractions is demonstrated. Using the derived kinetic parameters, the β ⇒ α transformation in a Ti-6Al-4V alloy can be described for any cooling path and condition. An interpretation of the results from the point of view of activation energy for nucleation is also presented.

Re-scan confocal microscopy: scanning twice for better resolution

PubMed Central

De Luca, Giulia M.R.; Breedijk, Ronald M.P.; Brandt, Rick A.J.; Zeelenberg, Christiaan H.C.; de Jong, Babette E.; Timmermans, Wendy; Azar, Leila Nahidi; Hoebe, Ron A.; Stallinga, Sjoerd; Manders, Erik M.M.

2013-01-01

We present a new super-resolution technique, Re-scan Confocal Microscopy (RCM), based on standard confocal microscopy extended with an optical (re-scanning) unit that projects the image directly on a CCD-camera. This new microscope has improved lateral resolution and strongly improved sensitivity while maintaining the sectioning capability of a standard confocal microscope. This simple technology is typically useful for biological applications where the combination high-resolution and high-sensitivity is required. PMID:24298422

Re-scan confocal microscopy: scanning twice for better resolution.

PubMed

De Luca, Giulia M R; Breedijk, Ronald M P; Brandt, Rick A J; Zeelenberg, Christiaan H C; de Jong, Babette E; Timmermans, Wendy; Azar, Leila Nahidi; Hoebe, Ron A; Stallinga, Sjoerd; Manders, Erik M M

2013-01-01

We present a new super-resolution technique, Re-scan Confocal Microscopy (RCM), based on standard confocal microscopy extended with an optical (re-scanning) unit that projects the image directly on a CCD-camera. This new microscope has improved lateral resolution and strongly improved sensitivity while maintaining the sectioning capability of a standard confocal microscope. This simple technology is typically useful for biological applications where the combination high-resolution and high-sensitivity is required.

Advanced scanning probe lithography.

PubMed

Garcia, Ricardo; Knoll, Armin W; Riedo, Elisa

2014-08-01

The nanoscale control afforded by scanning probe microscopes has prompted the development of a wide variety of scanning-probe-based patterning methods. Some of these methods have demonstrated a high degree of robustness and patterning capabilities that are unmatched by other lithographic techniques. However, the limited throughput of scanning probe lithography has prevented its exploitation in technological applications. Here, we review the fundamentals of scanning probe lithography and its use in materials science and nanotechnology. We focus on robust methods, such as those based on thermal effects, chemical reactions and voltage-induced processes, that demonstrate a potential for applications.

In vivo differentiation of complementary contrast media at dual-energy CT.

PubMed

Mongan, John; Rathnayake, Samira; Fu, Yanjun; Wang, Runtang; Jones, Ella F; Gao, Dong-Wei; Yeh, Benjamin M

2012-10-01

To evaluate the feasibility of using a commercially available clinical dual-energy computed tomographic (CT) scanner to differentiate the in vivo enhancement due to two simultaneously administered contrast media with complementary x-ray attenuation ratios. Approval from the institutional animal care and use committee was obtained, and National Institutes of Health guidelines for the care and use of laboratory animals were observed. Dual-energy CT was performed in a set of iodine and tungsten solution phantoms and in a rabbit in which iodinated intravenous and bismuth subsalicylate oral contrast media were administered. In addition, a second rabbit was studied after intravenous administration of iodinated and tungsten cluster contrast media. Images were processed to produce virtual monochromatic images that simulated the appearance of conventional single-energy scans, as well as material decomposition images that separate the attenuation due to each contrast medium. Clear separation of each of the contrast media pairs was seen in the phantom and in both in vivo animal models. Separation of bowel lumen from vascular contrast medium allowed visualization of bowel wall enhancement that was obscured by intraluminal bowel contrast medium on conventional CT scans. Separation of two vascular contrast media in different vascular phases enabled acquisition of a perfectly coregistered CT angiogram and venous phase-enhanced CT scan simultaneously in a single examination. Commercially available clinical dual-energy CT scanners can help differentiate the enhancement of selected pairs of complementary contrast media in vivo. © RSNA, 2012.

Development and Testing of a Scanning Differential Absorption Lidar For Carbon Sequestration Site Monitoring

NASA Astrophysics Data System (ADS)

Soukup, B.; Johnson, W.; Repasky, K. S.; Carlsten, J. L.

2013-12-01

A scanning differential absorption lidar (DIAL) instrument for carbon sequestration site monitoring is under development and testing at Montana State University. The laser transmitter uses two tunable discrete mode laser diodes (DMLD) operating in the continuous wave (cw) mode with one locked to the on-line absorption wavelength at 1571.4067 nm and the second operating at the off-line wavelength at 1571.2585 nm. Two in-line fiber optic switches are used to switch between on-line and off-line operation. After the fiber optic switches, an acousto-optic modulator (AOM) is used to generate a pulse train used to injection seed an erbium doped fiber amplifier (EDFA) to produce eye-safe laser pulses with maximum pulse energies of 66 J and a pulse repetition frequency of 15 kHz. The DIAL receiver uses a 28 cm diameter Schmidt-Cassegrain telescope to collect that backscattered light, which is then monitored using a fiber coupled photo-multiplier tube (PMT) module operating in the photon counting mode. The PMT has a 3% quantum efficiency, a dark count rate of 90 kHz, and a maximum count rate of 1 MHz. Recently, a fiber coupled avalanche photodiode (APD) operating in the geiger mode has been incorporated into the DIAL receiver. The APD has a quantum efficiency of 10%, a dark count rate of 10 kHz, and a maximum count rate of 1 MHz and provides a much larger dynamic range than the PMT. Both the PMT and APD provide TTL logic pulses that are monitored using a multichannel scaler card used to count the return photons as a function of time of flight and are thus interchangeable. The DIAL instrument was developed at the 1.571 m wavelength to take advantage of commercial-off-the-shelf components. The instrument is operated using a custom Labview program that switches to the DMLD operating at the on-line wavelength, locks this laser to a user defined wavelength setting, and collects return signals for a user defined time. The control program switches to the DMLD operating at the off

Amino acids as co-amorphous stabilizers for poorly water soluble drugs--Part 1: preparation, stability and dissolution enhancement.

PubMed

Löbmann, Korbinian; Grohganz, Holger; Laitinen, Riikka; Strachan, Clare; Rades, Thomas

2013-11-01

Poor aqueous solubility of an active pharmaceutical ingredient (API) is one of the most pressing problems in pharmaceutical research and development because up to 90% of new API candidates under development are poorly water soluble. These drugs usually have a low and variable oral bioavailability, and therefore an unsatisfactory therapeutic effect. One of the most promising approaches to increase dissolution rate and solubility of these drugs is the conversion of a crystalline form of the drug into its respective amorphous form, usually by incorporation into hydrophilic polymers, forming glass solutions. However, this strategy only led to a small number of marketed products usually because of inadequate physical stability of the drug (crystallization). In this study, we investigated a fundamentally different approach to stabilize the amorphous form of drugs, namely the use of amino acids as small molecular weight excipients that form specific molecular interactions with the drug resulting in co-amorphous forms. The two poorly water soluble drugs carbamazepine and indomethacin were combined with amino acids from the binding sites of the biological receptors of these drugs. Mixtures of drug and the amino acids arginine, phenylalanine, tryptophan and tyrosine were prepared by vibrational ball milling. Solid-state characterization with X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) revealed that the various blends could be prepared as homogeneous, single phase co-amorphous formulations indicated by the appearance of an amorphous halo in the XRPD diffractograms and a single glass transition temperature (Tg) in the DSC measurements. In addition, the Tgs of the co-amorphous mixtures were significantly increased over those of the individual drugs. The drugs remained chemically stable during the milling process and the co-amorphous formulations were generally physically stable over at least 6 months at 40 °C under dry conditions. The

An efficient scan diagnosis methodology according to scan failure mode for yield enhancement

NASA Astrophysics Data System (ADS)

Kim, Jung-Tae; Seo, Nam-Sik; Oh, Ghil-Geun; Kim, Dae-Gue; Lee, Kyu-Taek; Choi, Chi-Young; Kim, InSoo; Min, Hyoung Bok

2008-12-01

Yield has always been a driving consideration during fabrication of modern semiconductor industry. Statistically, the largest portion of wafer yield loss is defective scan failure. This paper presents efficient failure analysis methods for initial yield ramp up and ongoing product with scan diagnosis. Result of our analysis shows that more than 60% of the scan failure dies fall into the category of shift mode in the very deep submicron (VDSM) devices. However, localization of scan shift mode failure is very difficult in comparison to capture mode failure because it is caused by the malfunction of scan chain. Addressing the biggest challenge, we propose the most suitable analysis method according to scan failure mode (capture / shift) for yield enhancement. In the event of capture failure mode, this paper describes the method that integrates scan diagnosis flow and backside probing technology to obtain more accurate candidates. We also describe several unique techniques, such as bulk back-grinding solution, efficient backside probing and signal analysis method. Lastly, we introduce blocked chain analysis algorithm for efficient analysis of shift failure mode. In this paper, we contribute to enhancement of the yield as a result of the combination of two methods. We confirm the failure candidates with physical failure analysis (PFA) method. The direct feedback of the defective visualization is useful to mass-produce devices in a shorter time. The experimental data on mass products show that our method produces average reduction by 13.7% in defective SCAN & SRAM-BIST failure rates and by 18.2% in wafer yield rates.

Environmental Scanning Report.

ERIC Educational Resources Information Center

Truckee Meadows Community Coll., Sparks, NV.

This report describes Truckee Meadows Community College's (Nevada) environmental scanning process and results. The college decided that environmental scanning and forecasting techniques should be used to plan for both short-term and long-term external factors that impact programs, enrollment, and budgets. Strategic goals include: (1) keeping pace…

Confocal laser scanning microscopy detection of chlorophylls and carotenoids in chloroplasts and chromoplasts of tomato fruit.

PubMed

D'Andrea, Lucio; Amenós, Montse; Rodríguez-Concepción, Manuel

2014-01-01

Plant cells are unique among eukaryotic cells because of the presence of plastids, including chloroplasts and chromoplasts. Chloroplasts are found in green tissues and harbor the photosynthetic machinery (including chlorophyll molecules), while chromoplasts are present in non-photosynthetic tissues and accumulate large amounts of carotenoids. During tomato fruit development, chloroplasts are converted into chromoplasts that accumulate high levels of lycopene, a linear carotenoid responsible for the characteristic red color of ripe fruit. Here, we describe a simple and fast method to detect both types of fully differentiated plastids (chloroplasts and chromoplasts), as well as intermediate stages, in fresh tomato fruits. The method is based on the differential autofluorescence of chlorophylls and carotenoids (lycopene) detected by Confocal Laser Scanning Microscopy.

In vivo flow cytometry for blood cell analysis using differential epi-detection of forward scattered light

NASA Astrophysics Data System (ADS)

Paudel, Hari P.; Jung, Yookyung; Raphael, Anthony; Alt, Clemens; Wu, Juwell; Runnels, Judith; Lin, Charles P.

2018-02-01

The present standard of blood cell analysis is an invasive procedure requiring the extraction of patient's blood, followed by ex-vivo analysis using a flow cytometer or a hemocytometer. We are developing a noninvasive optical technique that alleviates the need for blood extraction. For in-vivo blood analysis we need a high speed, high resolution and high contrast label-free imaging technique. In this proceeding report, we reported a label-free method based on differential epi-detection of forward scattered light, a method inspired by Jerome Mertz's oblique back-illumination microscopy (OBM) (Ford et al, Nat. Meth. 9(12) 2012). The differential epi-detection of forward light gives phase contrast image at diffraction-limited resolution. Unlike reflection confocal microscopy (RCM), which detects only sharp refractive index variation and suffers from speckle noise, this technique is suitable for detection of subtle variation of refractive index in biological tissue and it provides the shape and the size of cells. A custom built high speed electronic detection circuit board produces a real-time differential signal which yields image contrast based on phase gradient in the sample. We recorded blood flow in-vivo at 17.2k lines per second in line scan mode, or 30 frames per second (full frame), or 120 frame per second (quarter frame) in frame scan mode. The image contrast and speed of line scan data recording show the potential of the system for noninvasive blood cell analysis.

Environmental Scanning and the Information Manager.

ERIC Educational Resources Information Center

Newsome, James; McInerney, Claire

1990-01-01

Discusses nine components of an environmental scanning model: selecting the scanning team; selecting resources to scan; choosing criteria for scanning; scanning the resources; identifying signals of new issues; selecting key events/issues; monitoring and analyzing events/issues; disseminating information; and deciding on appropriate organizational…

Multiline radar scan

NASA Technical Reports Server (NTRS)

Levinson, S.

1977-01-01

Scanning scheme is more efficient than conventional scanning. Originally designed for optical radar in space vehicles, scheme may also find uses in site-surveillance security systems and in other industrial applications. It should be particularly useful when system must run on battery energy, as would be case in power outages.

Diffusion Weighted MRI and MRS to Differentiate Radiation Necrosis and Recurrent Disease in Gliomas

NASA Astrophysics Data System (ADS)

Ewell, Lars

2006-03-01

A difficulty encountered in the diagnosis of patients with gliomas is the differentiation between recurrent disease and Radiation Induced Necrosis (RIN). Both can appear as ‘enhancing lesions’ on a typical T2 weighted MRI scan. Magnetic Resonance Spectroscopy (MRS) and Diffusion Weighted MRI (DWMRI) have the potential to be helpful regarding this differentiation. MRS has the ability to measure the concentration of brain metabolites, such as Choline, Creatin and N- Acetyl Aspartate, the ratios of which have been shown to discriminate between RIN and recurrent disease. DWMRI has been linked via a rise in the Apparent Diffusion Coefficient (ADC) to successful treatment of disease. Using both of these complimentary non-invasive imaging modalities, we intend to initiate an imaging protocol whereby we will study how best to combine metabolite ratios and ADC values to obtain the most useful information in the least amount of scan time. We will look for correlations over time between ADC values, and MRS, among different sized voxels.

Infrared Scanning

NASA Technical Reports Server (NTRS)

1987-01-01

United Scanning Technologies, Inc.'s Infrared thermography is a relatively new noncontact, nondestructive inspection and testing tool which makes temperatures visible to the human eye. Infrared scanning devices produce images that show, by color or black and white shading differences, heat losses through damaged or inadequately insulated walls or roofs. The MISS Aeroscan services are designed to take the guesswork out of industrial roof maintenance and provide companies big savings by identifying the location of moisture damage from roof leaks, effectively targeting maintenance attention.

Self-calibrating d-scan: measuring ultrashort laser pulses on-target using an arbitrary pulse compressor.

PubMed

Alonso, Benjamín; Sola, Íñigo J; Crespo, Helder

2018-02-19

In most applications of ultrashort pulse lasers, temporal compressors are used to achieve a desired pulse duration in a target or sample, and precise temporal characterization is important. The dispersion-scan (d-scan) pulse characterization technique usually involves using glass wedges to impart variable, well-defined amounts of dispersion to the pulses, while measuring the spectrum of a nonlinear signal produced by those pulses. This works very well for broadband few-cycle pulses, but longer, narrower bandwidth pulses are much more difficult to measure this way. Here we demonstrate the concept of self-calibrating d-scan, which extends the applicability of the d-scan technique to pulses of arbitrary duration, enabling their complete measurement without prior knowledge of the introduced dispersion. In particular, we show that the pulse compressors already employed in chirped pulse amplification (CPA) systems can be used to simultaneously compress and measure the temporal profile of the output pulses on-target in a simple way, without the need of additional diagnostics or calibrations, while at the same time calibrating the often-unknown differential dispersion of the compressor itself. We demonstrate the technique through simulations and experiments under known conditions. Finally, we apply it to the measurement and compression of 27.5 fs pulses from a CPA laser.

Sub-nanometre resolution imaging of polymer–fullerene photovoltaic blends using energy-filtered scanning electron microscopy

PubMed Central

Masters, Robert C.; Pearson, Andrew J.; Glen, Tom S.; Sasam, Fabian-Cyril; Li, Letian; Dapor, Maurizio; Donald, Athene M.; Lidzey, David G.; Rodenburg, Cornelia

2015-01-01

The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials. PMID:25906738

Sub-nanometre resolution imaging of polymer-fullerene photovoltaic blends using energy-filtered scanning electron microscopy.

PubMed

Masters, Robert C; Pearson, Andrew J; Glen, Tom S; Sasam, Fabian-Cyril; Li, Letian; Dapor, Maurizio; Donald, Athene M; Lidzey, David G; Rodenburg, Cornelia

2015-04-24

The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials.

Codification of scan path parameters and development of perimeter scan strategies for 3D bowl-shaped laser forming

NASA Astrophysics Data System (ADS)

Tavakoli, A.; Naeini, H. Moslemi; Roohi, Amir H.; Gollo, M. Hoseinpour; Shahabad, Sh. Imani

2018-01-01

In the 3D laser forming process, developing an appropriate laser scan pattern for producing specimens with high quality and uniformity is critical. This study presents certain principles for developing scan paths. Seven scan path parameters are considered, including: (1) combined linear or curved path; (2) type of combined linear path; (3) order of scan sequences; (4) the position of the start point in each scan; (5) continuous or discontinuous scan path; (6) direction of scan path; and (7) angular arrangement of combined linear scan paths. Regarding these path parameters, ten combined linear scan patterns are presented. Numerical simulations show continuous hexagonal, scan pattern, scanning from outer to inner path, is the optimized. In addition, it is observed the position of the start point and the angular arrangement of scan paths is the most effective path parameters. Also, further experimentations show four sequences due to creat symmetric condition enhance the height of the bowl-shaped products and uniformity. Finally, the optimized hexagonal pattern was compared with the similar circular one. In the hexagonal scan path, distortion value and standard deviation rather to edge height of formed specimen is very low, and the edge height despite of decreasing length of scan path increases significantly compared to the circular scan path. As a result, four-sequence hexagonal scan pattern is proposed as the optimized perimeter scan path to produce bowl-shaped product.

Two-dimensional thermography image retrieval from zig-zag scanned data with TZ-SCAN

NASA Astrophysics Data System (ADS)

Okumura, Hiroshi; Yamasaki, Ryohei; Arai, Kohei

2008-10-01

TZ-SCAN is a simple and low cost thermal imaging device which consists of a single point radiation thermometer on a tripod with a pan-tilt rotator, a DC motor controller board with a USB interface, and a laptop computer for rotator control, data acquisition, and data processing. TZ-SCAN acquires a series of zig-zag scanned data and stores the data as CSV file. A 2-D thermal distribution image can be retrieved by using the second quefrency peak calculated from TZ-SCAN data. An experiment is conducted to confirm the validity of the thermal retrieval algorithm. The experimental result shows efficient accuracy for 2-D thermal distribution image retrieval.

Evaluation of Efficacy of Bone Scan With SPECT/CT in the Management of Low Back Pain: A Study Supported by Differential Diagnostic Local Anesthetic Blocks.

PubMed

Jain, Anuj; Jain, Suruchi; Agarwal, Anil; Gambhir, Sanjay; Shamshery, Chetna; Agarwal, Amita

2015-12-01

Conventional radiologic modalities provide details only about the anatomic aspect of the various structures of the spine. Frequently the structures that show abnormal morphology may not be the cause of low back pain (LBP). Functional imaging in the form of bone scan along with single photon emission computerized tomography (SPECT/CT) may be helpful in identifying structures causing pain, whether morphologically normal or not. The objective of this study is to evaluate the role of bone scan with SPECT/CT in management of patients with LBP. This is randomized double-blinded controlled study performed on 80 patients with LBP aged 20 to 80 years, ASA physical status I to III. Patients were randomized into bone scan and control groups consisting of 40 patients each. On the basis of the clinical features and radiologic findings a clinical diagnosis was made. After making a clinical diagnosis, the patients in bone scan group were subjected to bone scan with SPECT/CT. On the basis of the finding of the bone scan and SPECT/CT, a new working diagnosis was made and intervention was performed according to the new working diagnosis. Diagnostic blocks in the control group were given based on clinical diagnosis. Controlled comparative diagnostic blocks were performed with local anesthetic. The pain score just after the diagnostic block and at the time of discharge (approximately 4 h later) was recorded; the pain relief was recorded in percentage. In both the groups, sacroilitis was the most common diagnosis followed by facet joint arthropathy. The number of patients obtaining pain relief of >50% was significantly higher in the bone scan-positive group as compared with the control group. Three new clinical conditions were identified in the bone scan group. These conditions were multiple myeloma, avascular necrosis of the femoral head, and ankylosing spondylitis. Bone scan with SPECT/CT was found to complement the clinical workup of patients with LBP. Inclusion of bone scan with

SU-F-I-46: Optimizing Dose Reduction in Adult Head CT Protocols While Maintaining Image Quality in Postmortem Head Scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipnharski, I; Carranza, C; Quails, N

Purpose: To optimize adult head CT protocol by reducing dose to an appropriate level while providing CT images of diagnostic quality. Methods: Five cadavers were scanned from the skull base to the vertex using a routine adult head CT protocol (120 kVp, 270 mA, 0.75 s rotation, 0.5 mm × 32 detectors, 70.8 mGy CTDIvol) followed by seven reduced-dose protocols with varying combinations of reduced tube current, reduced rotation time, and increased detectors with CTDIvol ranging from 38.2 to 65.6 mGy. Organ doses were directly measured with 21 OSL dosimeters placed on the surface and implanted in the head bymore » a neurosurgeon. Two neuroradiologists assessed grey-white matter differentiation, fluid space, ventricular size, midline shift, brain mass, edema, ischemia, and skull fractures on a three point scale: (1) Unacceptable, (2) Borderline Acceptable, and (3) Acceptable. Results: For the standard scan, doses to the skin, lens of the eye, salivary glands, thyroid, and brain were 37.55 mGy, 49.65 mGy, 40.67 mGy, 4.63 mGy, and 27.33 mGy, respectively. Two cadavers had cerebral edema due to changing dynamics of postmortem effects, causing the grey-white matter differentiation to appear less distinct. Two cadavers with preserved grey-white matter received acceptable scores for all image quality features for the protocol with a CTDIvol of 57.3 mGy, allowing organ dose savings ranging from 34% to 45%. One cadaver allowed for greater dose reduction for the protocol with a CTDIvol of 42 mGy. Conclusion: Efforts to optimize scan protocol should consider both dose and clinical image quality. This is made possible with postmortem subjects, whose brains are similar to patients, allowing for an investigation of ideal scan parameters. Radiologists at our institution accepted scan protocols acquired with lower scan parameters, with CTDIvol values closer to the American College of Radiology’s (ACR) Achievable Dose level of 57 mGy.« less

The usefulness of fluorine-18 fluorodeoxyglucose PET in the detection of recurrence in patients with differentiated thyroid cancer with elevated thyroglobulin and negative radioiodine whole-body scan.

PubMed

Stangierski, Adam; Kaznowski, Jaroslaw; Wolinski, Kosma; Jodlowska, Elzbieta; Michaliszyn, Piotr; Kubiak, Katarzyna; Czepczynski, Rafal; Ruchala, Marek

2016-09-01

PET/computed tomography (CT) using fluorine-18 fluorodeoxyglucose (F-FDG) has been used in the diagnosis of recurrence and metastases of differentiated thyroid cancer (DTC) in cases of negative whole-body scan (WBS) despite elevated concentrations of stimulated thyroglobulin (Tg). To assess the utility of PET/CT in the detection of recurrence among patients with DTC with increased Tg levels and negative results of WBS. PET/CT results were retrospectively analyzed in patients with DTC with increased Tg and negative results of WBS as well as negative cervical ultrasonography and chest radiography. PET-CT was performed 1-2 weeks after recent diagnostics under conditions of endogenous or exogenous thyroid-stimulating hormone stimulation. PET/CT was performed using a Discovery ST scanner 1 h after an intravenously F-FDG injection (activity 4-5 MBq/kg). To determine the cutoff value of Tg, receiver operating characteristic curves were analyzed. Sixty-nine patients with DTC (48 women, 21 men) aged 22-83 years (mean 50.9±17.5 years) were qualified. In 44 patients (63.8%), PET/CT indicated lesions of DTC. Thirty (43.5%) patients had F-FDG positive findings. In the remaining 14 patients (20.3%), lesions were found in CT only. Patients with a positive PET/CT scan had significantly higher Tg values than patients with a negative PET/CT (mean 143.8 vs. 26.5 ng/ml, P=0.03). The cutoff value of Tg concentration measured with the receiver operating characteristic analysis was 32.9 ng/ml. PET/CT is a useful tool in the detection of recurrence among thyroid cancer patients in cases of conflicting results of standard procedures, particularly for those with high Tg levels and negative WBS. The probability of obtaining a positive PET-CT result increases with the level of Tg.

Through-focus scanning optical microscopy (TSOM) with adaptive optics

NASA Astrophysics Data System (ADS)

Lee, Jun Ho; Park, Gyunam; Jeong, Junhee; Park, Chris

2018-03-01

Through-focus optical microscopy (TSOM) with nanometer-scale lateral and vertical sensitivity levels matching those of scanning electron microscopy has been demonstrated to be useful both for 3D inspections and metrology assessments. In 2014, funded by two private companies (Nextin/Samsung Electronics) and the Korea Evaluation Institute of Industrial Technology (KEIT), a research team from four universities in South Korea set out to investigate core technologies for developing in-line TSOM inspection and metrology tools, with the respective teams focusing on optics implementation, defect inspection, computer simulation and high-speed metrology matching. We initially confirmed the reported validity of the TSOM operation through a computer simulation, after which we implemented the TSOM operation by throughfocus scanning of existing UV (355nm) and IR (800nm) inspection tools. These tools have an identical sampling distance of 150 nm but have different resolving distances (310 and 810 nm, respectively). We initially experienced some improvement in the defect inspection sensitivity level over TSV (through-silicon via) samples with 6.6 μm diameters. However, during the experiment, we noted sensitivity and instability issues when attempting to acquire TSOM images. As TSOM 3D information is indirectly extracted by differentiating a target TSOM image from reference TSOM images, any instability or mismatch in imaging conditions can result in measurement errors. As a remedy to such a situation, we proposed the application of adaptive optics to the TSOM operation and developed a closed-loop system with a tip/tilt mirror and a Shack-Hartmann sensor on an optical bench. We were able to keep the plane position within in RMS 0.4 pixel by actively compensating for any position instability which arose during the TSOM scanning process along the optical axis. Currently, we are also developing another TSOM tool with a deformable mirror instead of a tip/tilt mirror, in which case we

Three-dimensional scanning confocal laser microscope

DOEpatents

Anderson, R. Rox; Webb, Robert H.; Rajadhyaksha, Milind

1999-01-01

A confocal microscope for generating an image of a sample includes a first scanning element for scanning a light beam along a first axis, and a second scanning element for scanning the light beam at a predetermined amplitude along a second axis perpendicular to the first axis. A third scanning element scans the light beam at a predetermined amplitude along a third axis perpendicular to an imaging plane defined by the first and second axes. The second and third scanning element are synchronized to scan at the same frequency. The second and third predetermined amplitudes are percentages of their maximum amplitudes. A selector determines the second and third predetermined amplitudes such that the sum of the percentages is equal to one-hundred percent.

Correcting scan-to-scan response variability for a radiochromic film-based reference dosimetry system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, David, E-mail: rcfilmconsulting@gmail.com; Devic, Slobodan

Purpose: In radiochromic film dosimetry systems, measurements are usually obtained from film images acquired on a CCD-based flatbed scanner. The authors investigated factors affecting scan-to-scan response variability leading to increased dose measurement uncertainty. Methods: The authors used flatbed document scanners to repetitively scan EBT3 radiochromic films exposed to doses 0–1000 cGy, together with three neutral density filters and three blue optical filters. Scanning was performed under two conditions: scanner lid closed and scanner lid opened/closed between scans. The authors also placed a scanner in a cold room at 9 °C and later in a room at 22 °C and scanned EBT3 filmsmore » to explore temperature effects. Finally, the authors investigated the effect of altering the distance between the film and the scanner’s light source. Results: Using a measurement protocol to isolate the contribution of the CCD and electronic circuitry of the scanners, the authors found that the standard deviation of response measurements for the EBT3 film model was about 0.17% for one scanner and 0.09% for the second. When the lid of the first scanner was opened and closed between scans, the average scan-to-scan difference of responses increased from 0.12% to 0.27%. Increasing the sample temperature during scanning changed the RGB response values by about −0.17, −0.14, and −0.05%/°C, respectively. Reducing the film-to-light source distance increased the RBG response values about 1.1, 1.3, and 1.4%/mm, respectively. The authors observed that films and film samples were often not flat with some areas up to 8 mm away from the scanner’s glass window. Conclusions: In the absence of measures to deal with the response irregularities, each factor the authors investigated could lead to dose uncertainty >2%. Those factors related to the film-to-light source distance could be particularly impactful since the authors observed many instances where the curl of film samples

The coupling hypothesis: why genome scans may fail to map local adaptation genes.

PubMed

Bierne, Nicolas; Welch, John; Loire, Etienne; Bonhomme, François; David, Patrice

2011-05-01

Genomic scans of multiple populations often reveal marker loci with greatly increased differentiation between populations. Often this differentiation coincides in space with contrasts in ecological factors, forming a genetic-environment association (GEA). GEAs imply a role for local adaptation, and so it is tempting to conclude that the strongly differentiated markers are themselves under ecologically based divergent selection, or are closely linked to loci under such selection. Here, we highlight an alternative and neglected explanation: intrinsic (i.e. environment-independent) pre- or post-zygotic genetic incompatibilities rather than local adaptation can be responsible for increased differentiation. Intrinsic genetic incompatibilities create endogenous barriers to gene flow, also known as tension zones, whose location can shift over time. However, tension zones have a tendency to become trapped by, and therefore to coincide with, exogenous barriers due to ecological selection. This coupling of endogenous and exogenous barriers can occur easily in spatially subdivided populations, even if the loci involved are unlinked. The result is that local adaptation explains where genetic breaks are positioned, but not necessarily their existence, which can be best explained by endogenous incompatibilities. More precisely, we show that (i) the coupling of endogenous and exogenous barriers can easily occur even when ecological selection is weak; (ii) when environmental heterogeneity is fine-grained, GEAs can emerge at incompatibility loci, but only locally, in places where habitats and gene pools are sufficiently intermingled to maintain linkage disequilibria between genetic incompatibilities, local-adaptation genes and neutral loci. Furthermore, the association between the locally adapted and intrinsically incompatible alleles (i.e. the sign of linkage disequilibrium between endogenous and exogenous loci) is arbitrary and can form in either direction. Reviewing results from

The utility of repeat sestamibi scans in patients with primary hyperparathyroidism after an initial negative scan.

PubMed

Krishnamurthy, Vikram D; Sound, Sara; Okoh, Alexis K; Yazici, Pinar; Yigitbas, Hakan; Neumann, Donald; Doshi, Krupa; Berber, Eren

2017-06-01

We analyzed the utility of repeated sestambi scans in patients with primary hyperparathyroidism and its effects on operative referral. We carried out a retrospective review of patients with primary hyperparathyroidism who underwent repeated sestambi scans exclusively within our health system between 1996-2015. Patient demographic, presentation, laboratory, imaging, operative, and pathologic data were reviewed. Univariate analysis with JMP Pro v12 was used to identify factors associated with conversion from an initial negative to a subsequent positive scan. After exclusion criteria (including reoperations), we identified 49 patients in whom 59% (n = 29) of subsequent scans remained negative and 41% (n = 20) converted to positive. Factors associated with an initial negative to a subsequent positive scan included classic presentation and second scans with iodine subtraction (P = .04). Nonsurgeons were less likely to order an iodine-subtraction scan (P < .05). Fewer patients with negative imaging were referred to surgery (33% vs 100%, P = .005), and median time to operation after the first negative scan was 25 months (range 1.4-119). Surgeon-performed ultrasonography had greater sensitivity and positive predictive value than repeated sestamibi scans. Negative sestambi scans decreased and delayed operative referral. Consequently, we identified several process improvement initiatives, including education regarding superior institutional imaging. Combining all findings, we created an algorithm for evaluating patients with primary hyperparathyroidism after initially negative sestamibi scans, which incorporates surgeon-performed ultrasonography. Copyright © 2016 Elsevier Inc. All rights reserved.

Alendronate-Eluting Biphasic Calcium Phosphate (BCP) Scaffolds Stimulate Osteogenic Differentiation

PubMed Central

Kim, Sung Eun; Lee, Deok-Won; Kang, Eun Young; Jeong, Won Jae; Lee, Boram; Jeong, Myeong Seon; Kim, Hak Jun; Park, Kyeongsoon; Song, Hae-Ryong

2015-01-01

Biphasic calcium phosphate (BCP) scaffolds have been widely used in orthopedic and dental fields as osteoconductive bone substitutes. However, BCP scaffolds are not satisfactory for the stimulation of osteogenic differentiation and maturation. To enhance osteogenic differentiation, we prepared alendronate- (ALN-) eluting BCP scaffolds. The coating of ALN on BCP scaffolds was confirmed by scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). An in vitro release study showed that release of ALN from ALN-eluting BCP scaffolds was sustained for up to 28 days. In vitro results revealed that MG-63 cells grown on ALN-eluting BCP scaffolds exhibited increased ALP activity and calcium deposition and upregulated gene expression of Runx2, ALP, OCN, and OPN compared with the BCP scaffold alone. Therefore, this study suggests that ALN-eluting BCP scaffolds have the potential to effectively stimulate osteogenic differentiation. PMID:26221587

Internal scanning method as unique imaging method of optical vortex scanning microscope

NASA Astrophysics Data System (ADS)

Popiołek-Masajada, Agnieszka; Masajada, Jan; Szatkowski, Mateusz

2018-06-01

The internal scanning method is specific for the optical vortex microscope. It allows to move the vortex point inside the focused vortex beam with nanometer resolution while the whole beam stays in place. Thus the sample illuminated by the focused vortex beam can be scanned just by the vortex point. We show that this method enables high resolution imaging. The paper presents the preliminary experimental results obtained with the first basic image recovery procedure. A prospect of developing more powerful tools for topography recovery with the optical vortex scanning microscope is discussed shortly.

The mechanism of interactions between tea polyphenols and porcine pancreatic alpha‐amylase: Analysis by inhibition kinetics, fluorescence quenching, differential scanning calorimetry and isothermal titration calorimetry

PubMed Central

Sun, Lijun; Gidley, Michael J.

2017-01-01

Scope This study aims to use a combination of biochemical and biophysical methods to derive greater mechanistic understanding of the interactions between tea polyphenols and porcine pancreatic α‐amylase (PPA). Methods and results The interaction mechanism was studied through fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) and compared with inhibition kinetics. The results showed that a higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA. The red‐shift of maximum emission wavelength of PPA bound with some polyphenols indicated a potential structural unfolding of PPA. This was also suggested by the decreased thermostability of PPA with these polyphenols in DSC thermograms. Through thermodynamic binding analysis of ITC and inhibition kinetics, the equilibrium of competitive inhibition was shown to result from the binding of particularly galloylated polyphenols with specific sites on PPA. There were positive linear correlations between the reciprocal of competitive inhibition constant (1/K ic), quenching constant (K FQ) and binding constant (K itc). Conclusion The combination of inhibition kinetics, FQ, DSC and ITC can reasonably characterize the interactions between tea polyphenols and PPA. The galloyl moiety is an important group in catechins and theaflavins in terms of binding with and inhibiting the activity of PPA. PMID:28618113

Estimation of Crystallinity of Nifedipine-Polyvinylpyrrolidone Solid Dispersion by Usage of Terahertz Time-Domain Spectroscopy and of X-Ray Powder Diffractometer.

PubMed

Takeuchi, Issei; Shimakura, Kemmaro; Kuroda, Hideki; Nakajima, Takehisa; Goto, Satoru; Makino, Kimiko

2015-12-01

Crystalline state of pharmaceutical materials is of great importance in preparation of pharmaceutics, because their physicochemical properties affect bioavailability, quality of products, therapeutic level and manufacturing process. In this study, we have estimated time-dependent changes of nifedipine in nifedipine-polyvinylpyrrolidone (PVP) solid dispersion by measuring terahertz time-domain spectroscopy (THz-TDS) and by X-ray powder diffractometry (XRPD), and compared their correlativity. Crystallinity of nifedipine-PVP solid dispersion was changed by storing the amorphous sample at 25°C-75°C and relative humidity of over 80% for 0.25-24.00 h. To compare the results of two types of measurements, we have used a general method of linear regression analysis. Crystallinities estimated using THz-TDS were plotted on the x-axis and that of XRPD were on the y-axis. From the result of the calculation, the correlativity of them was confirmed. THz-TDS has the capability of becoming the replacement of XRPD. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Specific phobias in older adults: characteristics and differential diagnosis.

PubMed

Coelho, Carlos M; Gonçalves, Daniela C; Purkis, Helena; Pocinho, Margarida; Pachana, Nancy A; Byrne, Gerard J

2010-08-01

Differential diagnosis implies identifying shared and divergent characteristics between clinical states. Clinical work with older adults demands not only the knowledge of nosological features associated with differential diagnosis, but also recognition of idiosyncratic factors associated with this population. Several factors can interfere with an accurate diagnosis of specific phobia in older cohorts. The goal of this paper is to review criteria for specific phobia and its differential diagnosis with panic disorder, agoraphobia, post-traumatic stress disorder and obsessive compulsive disorder, while stressing the specific factors associated with aging. A literature search regarding specific phobia in older adults was carried out using PubMed. Relevant articles were selected and scanned for further pertinent references. In addition, relevant references related to differential diagnosis and assessment were used. Etiologic factors, specificity of feared stimulus or situation, fear predictability and the nature of phobic situations are key points to be assessed when implementing a differential diagnosis of specific phobia. First, age-related sensory impairments are common and interfere both with information processing and communication. Second, medical illnesses create symptoms that might cause, interfere with, or mimic anxiety. Third, cohort effects might result in underreporting, through the inability to communicate or recognize anxiety symptoms, misattributing them to physical conditions. Finally, diagnostic criteria and screening instruments were usually developed using younger samples and are therefore not adapted to the functional and behavioral characteristics of older samples.

Morphological observation and characterization of the Pseudoregma bambucicola with the scanning electron microscope.

PubMed

Nong, Xiang; Zeng, Xuemei; Yang, Yaojun; Liang, Zi; Tang, Mei; Liao, Lejuan; Luo, Chaobing

2017-11-01

Both leica microscopic camera system and scanning electron microscopy was used to observe and characterize the feet, back, abdomen, antennae and mouthparts of the Pseudoregma bambucicola from the bamboo, Bambusa multiplex . The possible functions of all the external morphological characteristics of the P. bambucicola were described and discussed in detail, which offers a basis for further enriching the biology, phylogeny and ecological niche of the P. bambucicola . Moreover, the morphological results should contribute to morphological identification and differentiation of the P. bambucicola from other aphids in the same family.

Understanding effect of formulation and manufacturing variables on the critical quality attributes of warfarin sodium product.

PubMed

Rahman, Ziyaur; Korang-Yeboah, Maxwell; Siddiqui, Akhtar; Mohammad, Adil; Khan, Mansoor A

2015-11-10

Warfarin sodium (WS) is a narrow therapeutic index drug and its product quality should be thoroughly understood and monitored in order to avoid clinical performance issues. This study was focused on understanding the effect of manufacturing and formulation variables on WS product critical quality attributes (CQAs). Eight formulations were developed with lactose monohydrate (LM) or lactose anhydrous (LA), and were either wet granulated or directly compressed. Formulations were granulated either with ethanol, isopropyl alcohol (IPA) and IPA-water mixture (50:50). Formulations were characterized for IPA, water content, hardness, disintegration time (DT), assay, dissolution and drug physical forms (scanning electron microscopy (SEM), near infrared chemical imaging (NIR-CI), X-ray powder diffraction (XRPD) and solid state nuclear magnetic resonance (ssNMR)), and performed accelerated stability studies at 40°C/75% RH for three days. The DT and dissolution of directly compressed formulations were faster than wet granulated formulations. This was due to phase transformation of crystalline drug into its amorphous form as indicated by SEM, NIR-CI, XRPD and ssNMR data which itself act as a binder. Similarly, LM showed faster disintegration and dissolution than LA containing formulations. Stability results indicated an increase in hardness and DT, and a decrease in dissolution rate and extent. This was due to phase transformation of the drug and consolidation with particles' bonding. In conclusion, the CQAs of WS product were significantly affected by manufacturing and formulation variables. Published by Elsevier B.V.

Chemical and mineralogical characterization of chromite ore processing residue from two recent Indian disposal sites.

PubMed

Matern, Katrin; Kletti, Holger; Mansfeldt, Tim

2016-07-01

Chromite ore processing residue (COPR) is a hazardous waste. Nevertheless, deposition of COPR in uncontrolled surface landfills is still common practice in some countries. Whereas old (between at least 40 and 180 years) COPR from the temperate zone has been intensively investigated, information on COPR in other regions is restricted. Relatively young (<25 years) COPR samples obtained from two abandoned landfill sites in India were investigated by a modified total microwave digestion method, X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) in order to determine their chemical and mineralogical nature. By the use of microwave digestion with acid mixtures of HNO3, H3PO4, and HBF4 (5:3:2 vol), COPR was completely dissolved and element contents similar to those obtained by X-ray fluorescence were found. Total Cr contents of the two COPR accounted for 81 and 74 g kg(-1), of which 20 and 13% were present in the carcinogenic hexavalent form (CrVI). Apart from the common major mineral phases present in COPR reported earlier, a further Cr host mineral, grimaldiite [CrO(OH)], could be identified by XRPD and SEM. Additionally, well soluble Na2CrO4 was present. Improving the effectiveness of chromite ore processing and preventing the migration of Cr(VI) into water bodies are the main challenges when dealing with these COPR. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative results of autogenous ignition temperature measurements by ASTM G 72 and pressurized scanning calorimetry in gaseous oxygen

NASA Technical Reports Server (NTRS)

Bryan, C. J.; Lowrie, R.

1986-01-01

The autogenous ignition temperature of four materials was determined by ASTM (G 72) and pressurized differential scanning calorimetry at 0.68-, 3.4-, and 6.8-MPa oxygen pressure. All four materials were found to ignite at lower temperatures in the ASTM method. The four materials evaluated in this program were Neoprene, Vespel SP-21, Fluorel E-2160, and nylon 6/6.

[Differential diagnosis of dental enamel focal demineralization and fluorosis by means of spectrophotometry].

PubMed

Makarova, N E; Vinnichenko, Yu A

2018-01-01

The article presents the results of spectrophotometric tooth enamel scanning for differential diagnosis of focal enamel demineralization and fluorosis. Research was conducted in vivo on teeth affected by these diseases. VITA EasyShade spectrophotometer measurements were made on the affected area and on the visually healthy part of enamel. The lightness appeared as the only one differential significant optical characteristics of tooth enamel. Lightness metrics were higher in the case of initial caries than on the healthy part of enamel when these metrics were lower in the case of fluorosis than on the healthy part of enamel.

Reversible amorphous-crystalline phase changes in a wide range of Se1-xTex alloys studied using ultrafast differential scanning calorimetry

NASA Astrophysics Data System (ADS)

Vermeulen, Paul. A.; Momand, Jamo; Kooi, Bart J.

2014-07-01

The reversible amorphous-crystalline phase change in a chalcogenide material, specifically the Se1-xTex alloy, has been investigated for the first time using ultrafast differential scanning calorimetry. Heating rates and cooling rates up to 5000 K/s were used. Repeated reversible amorphous-crystalline phase switching was achieved by consecutively melting, melt-quenching, and recrystallizing upon heating. Using a well-conditioned method, the composition of a single sample was allowed to shift slowly from 15 at. %Te to 60 at. %Te, eliminating sample-to-sample variability from the measurements. Using Energy Dispersive X-ray Spectroscopy composition analysis, the onset of melting for different Te-concentrations was confirmed to coincide with the literature solidus line, validating the use of the onset of melting Tm as a composition indicator. The glass transition Tg and crystallization temperature Tc could be determined accurately, allowing the construction of extended phase diagrams. It was found that Tm and Tg increase (but Tg/Tm decrease slightly) with increasing Te-concentration. Contrarily, the Tc decreases substantially, indicating that the amorphous phase becomes progressively unfavorable. This coincides well with the observation that the critical quench rate to prevent crystallization increases about three orders of magnitude with increasing Te concentration. Due to the employment of a large range of heating rates, non-Arrhenius behavior was detected, indicating that the undercooled liquid SeTe is a fragile liquid. The activation energy of crystallization was found to increase 0.5-0.6 eV when the Te concentration increases from 15 to 30 at. % Te, but it ceases to increase when approaching 50 at. % Te.

Colour measurements of pigmented rice grain using flatbed scanning and image analysis

NASA Astrophysics Data System (ADS)

Kaisaat, Khotchakorn; Keawdonree, Nuttapong; Chomkokard, Sakchai; Jinuntuya, Noparit; Pattanasiri, Busara

2017-09-01

Recently, the National Bureau of Agricultural Commodity and Food Standards (ACFS) have drafted a manual of Thai colour rice standards. However, there are no quantitative descriptions of rice colour and its measurement method. These drawbacks might lead to misunderstanding for people who use the manual. In this work, we proposed an inexpensive method, using flatbed scanning together with image analysis, to quantitatively measure rice colour and colour uniformity. To demonstrate its general applicability for colour differentiation of rice, we applied it to different kinds of pigmented rice, including Riceberry rice with and without uniform colour and Chinese black rice.

The Scanning Process: Getting Started.

ERIC Educational Resources Information Center

Renfro, William L.; Morrison, James L.

1983-01-01

Scanning the external environment will become more essential to colleges in the coming decade. Developing an environmental scanning system can identify important emerging issues that may constitute either threats or opportunities. The organizational features of a mature scanning process are described. (MLW)

Radioisotope scanning in osseous sarcoidosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohatgi, P.K.

1980-01-01

Technetium-99m (/sup 99m/Tc)-labeled pyrophosphate or diphosphonate compounds and gallium-67 citrate (/sup 67/Ga) are two radionuclide scanning agents that are in widespread use in clinical practice. Technetium-99m pyrophosphate is used extensively for bone scanning to detect metastatic bone disease, benign bone tumors, osteomyelitis, benign hypertrophic osteoarthropathy, and Paget's disease. Only two reports describe abnormal /sup 99m/Tc/ pyrophosphate bone scans in four patients with osseous sarcoidosis. Gallium-67 scans are used primarily to localize neoplastic or inflammatory lesions anywhere in the body. In recent years /sup 67/Ga scans have also been used to detect the presence of both pulmonary and extrapulmonary sarcoidosis, butmore » there are no reports describing abnormal uptake of gallium in patients with osseous sarcoidosis. This report describes experience with radioisotope scanning in two patients with osseous sarcoidosis.« less

Mouse manipulation through single-switch scanning.

PubMed

Blackstien-Adler, Susie; Shein, Fraser; Quintal, Janet; Birch, Shae; Weiss, Patrice L Tamar

2004-01-01

Given the current extensive reliance on the graphical user interface, independent access to computer software requires that users be able to manipulate a pointing device of some type (e.g., mouse, trackball) or be able to emulate a mouse by some other means (e.g., scanning). The purpose of the present study was to identify one or more optimal single-switch scanning mouse emulation strategies. Four alternative scanning strategies (continuous Cartesian, discrete Cartesian, rotational, and hybrid quadrant/continuous Cartesian) were selected for testing based on current market availability as well as on theoretical considerations of their potential speed and accuracy. Each strategy was evaluated using a repeated measures study design by means of a test program that permitted mouse emulation via any one of four scanning strategies in a motivating environment; response speed and accuracy could be automatically recorded and considered in view of the motor, cognitive, and perceptual demands of each scanning strategy. Ten individuals whose disabilities required them to operate a computer via single-switch scanning participated in the study. Results indicated that Cartesian scanning was the preferred and most effective scanning strategy. There were no significant differences between results from the Continuous Cartesian and Discrete Cartesian scanning strategies. Rotational scanning was quite slow with respect to the other strategies, although it was equally accurate. Hybrid Quadrant scanning improved access time but at the cost of fewer correct selections. These results demonstrated the importance of testing and comparing alternate single-switch scanning strategies.

Influence of spray drying and dispersing agent on surface and dissolution properties of griseofulvin micro and nanocrystals.

PubMed

Shah, Dhaval A; Patel, Manan; Murdande, Sharad B; Dave, Rutesh H

2016-11-01

The purpose for the current research is to compare and evaluate physiochemical properties of spray-dried (SD) microcrystals (MCs), nanocrystals (NCs), and nanocrystals with a dispersion agent (NCm) from a poorly soluble compound. The characterization was carried out by performing size and surface analysis, interfacial tension (at particle moisture interface), and in-vitro drug dissolution rate experiments. Nanosuspensions were prepared by media milling and were spray-dried. The SD powders that were obtained were characterized morphologically using scanning electron microscopy (SEM), polarized light microscopy (PLM), and Flowchem. Solid-state characterization was performed using X-ray powder diffraction (XRPD), Fourier transfer infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) for the identification of the crystalline nature of all the SD powders. The powders were characterized for their redispersion tendency in the water and in pH 1.2. Significant differences in redispersion were noted for both the NCs in both dissolution media. The interfacial tension for particle moisture interface was determined by applying the BET (Braunauer-Emmett-Teller) equation to the vapor sorption data. No significant reduction in the interfacial tension was observed between MCs and NCs; however, a significant reduction in the interfacial tension was observed for NCm at both 25 °C and 35 °C temperatures. The difference in interfacial tension and redispersion behavior can be attributed to a difference in the wetting tendency for all the SD powders. The dissolution studies were carried out under sink and under non-sink conditions. The non-sink dissolution approach was found suitable for quantification of the dissolution rate enhancement, and also for providing the rank order to the SD formulations.

Methylprednisolone acetate-loaded hydroxyapatite nanoparticles as a potential drug delivery system for treatment of rheumatoid arthritis: In vitro and in vivo evaluations.

PubMed

Jafari, Samira; Maleki-Dizaji, Nasrin; Barar, Jaleh; Barzegar-Jalali, Mohammad; Rameshrad, Maryam; Adibkia, Khosro

2016-08-25

The objective of this study was to improve the therapeutic efficacy of methylprednisolone acetate (MPA) in the treatment of rheumatoid arthritis (RA) by incorporating the drug into the hydroxyapatite (HAp) nanoparticles. The nanoparticles were synthesized using a chemical precipitation technique and their size and morphology were evaluated by dynamic light scattering and scanning electron microscopy (SEM). The solid-state behavior of the nanoparticles was also characterized by operating X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The Brunauer-Emmett-Teller and Barrett-Joyner-Halenda N2 adsorption/desorption analyses were also performed to determine the surface area, Vm (the volume of the N2 adsorbed on the one gram of the HAp when the monolayer is complete) and the pore size of the samples. Furthermore, the therapeutic efficacy of the prepared nanoformulation on the adjuvant induced arthritic rats was assessed. HAp mesoporous nanoparticles with a particle size of 70.45nm, pore size of 2.71nm and drug loading of 44.53% were obtained. The specific surface area of HAp as well as the Vm values were decreased after the drug loading process. The nanoformulation revealed the slower drug release profile compared to the pure drug. The MTT assay indicated that the MPA-loaded nanoparticles had a lower cytotoxic effect on NIH-3T3 and CAOV-4 cell lines compared to the pure drug. Interestingly, the in vivo study confirmed that the drug-loaded nanoparticles could considerably decrease the paw volume and normalize the hematological abnormalities in the arthritic rats. Copyright © 2016 Elsevier B.V. All rights reserved.

In Vivo Differentiation of Complementary Contrast Media at Dual-Energy CT

PubMed Central

Mongan, John; Rathnayake, Samira; Fu, Yanjun; Wang, Runtang; Jones, Ella F.; Gao, Dong-Wei

2012-01-01

Purpose: To evaluate the feasibility of using a commercially available clinical dual-energy computed tomographic (CT) scanner to differentiate the in vivo enhancement due to two simultaneously administered contrast media with complementary x-ray attenuation ratios. Materials and Methods: Approval from the institutional animal care and use committee was obtained, and National Institutes of Health guidelines for the care and use of laboratory animals were observed. Dual-energy CT was performed in a set of iodine and tungsten solution phantoms and in a rabbit in which iodinated intravenous and bismuth subsalicylate oral contrast media were administered. In addition, a second rabbit was studied after intravenous administration of iodinated and tungsten cluster contrast media. Images were processed to produce virtual monochromatic images that simulated the appearance of conventional single-energy scans, as well as material decomposition images that separate the attenuation due to each contrast medium. Results: Clear separation of each of the contrast media pairs was seen in the phantom and in both in vivo animal models. Separation of bowel lumen from vascular contrast medium allowed visualization of bowel wall enhancement that was obscured by intraluminal bowel contrast medium on conventional CT scans. Separation of two vascular contrast media in different vascular phases enabled acquisition of a perfectly coregistered CT angiogram and venous phase–enhanced CT scan simultaneously in a single examination. Conclusion: Commercially available clinical dual-energy CT scanners can help differentiate the enhancement of selected pairs of complementary contrast media in vivo. © RSNA, 2012 PMID:22778447

Prediction of Phase Behavior of Spray-Dried Amorphous Solid Dispersions: Assessment of Thermodynamic Models, Standard Screening Methods and a Novel Atomization Screening Device with Regard to Prediction Accuracy

PubMed Central

Chavez, Pierre-François; Meeus, Joke; Robin, Florent; Schubert, Martin Alexander; Somville, Pascal

2018-01-01

The evaluation of drug–polymer miscibility in the early phase of drug development is essential to ensure successful amorphous solid dispersion (ASD) manufacturing. This work investigates the comparison of thermodynamic models, conventional experimental screening methods (solvent casting, quench cooling), and a novel atomization screening device based on their ability to predict drug–polymer miscibility, solid state properties (Tg value and width), and adequate polymer selection during the development of spray-dried amorphous solid dispersions (SDASDs). Binary ASDs of four drugs and seven polymers were produced at 20:80, 40:60, 60:40, and 80:20 (w/w). Samples were systematically analyzed using modulated differential scanning calorimetry (mDSC) and X-ray powder diffraction (XRPD). Principal component analysis (PCA) was used to qualitatively assess the predictability of screening methods with regards to SDASD development. Poor correlation was found between theoretical models and experimentally-obtained results. Additionally, the limited ability of usual screening methods to predict the miscibility of SDASDs did not guarantee the appropriate selection of lead excipient for the manufacturing of robust SDASDs. Contrary to standard approaches, our novel screening device allowed the selection of optimal polymer and drug loading and established insight into the final properties and performance of SDASDs at an early stage, therefore enabling the optimization of the scaled-up late-stage development. PMID:29518936

Structure and physical stability of hydrates and thermotropic mesophase of calcium benzoate.

PubMed

Terakita, Akira; Byrn, Stephen R

2006-05-01

The aim of this study is to investigate the hydration and the dehydration processes of calcium benzoate hydrates (trihydrate and monohydrate), thermotropic mesophases (dehydrated mesophase and lyophilized mesophase) and amorphous state, and the influence of their molecular order on those processes. X-ray analysis revealed that trihydrate has a planar structure composed of two types of planes-one from benzoic acid, water, and calcium ion and another from benzoic acid and water-and that both planes are linked by three water molecules. It was found that calcium benzoate was able to exist as thermotropic mesophases by dehydration of trihydrate and lyophilization. These mesophases were characterized by polarizing-light microscopy (PLM), X-ray powder diffraction (XRPD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Both mesophases prepared by two procedures showed some similar physical properties, but lyophilized mesophase seemed to have molecular structure with higher order than dehydrated mesophase. The mesophases exhibited different hydration behavior. The dehydrated mesophase showed a stepwise rehydration process where it became monohydrate first and then trihydrate. The lyophilized mesophase became trihydrate without appearance of monohydrate. An amorphous form could also be prepared and it rehydrated first to the monohydrate and then trihydrate. The results suggest that the more disordered dehydrated mesophase and amorphous state change to monohydrate whereas the more ordered lyophilized mesophase cannot change to monohydrate but only to trihydrate.

Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

PubMed Central

Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

2013-01-01

Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

[Role of CD2-associated protein in podocyte differentiation.].

PubMed

Jiang, Hua-Jun; Chang, Ying; Zhu, Zhong-Hua; Liu, Jian-She; Deng, An-Guo; Zhang, Chun

2008-02-25

To study the cellular changes and the potential role of CD2-associated protein (CD2AP) in podocyte differentiation, conditionally immortalized murine podocyte cell line was cultured in RPMI 1640 medium under permissive condition at 33 °C. After transfection with CD2AP small interfering RNA (siRNA) the cells were shifted to non-permissive condition at 37 °C. Simultaneously, untransfected cells were taken as differentiation control. The podocyte proliferation rate was determined by MTT method. The expressions of CD2AP, WT1, synaptopodin and nephrin mRNAs were examined by RT-PCR. CD2AP, WT1 and nephrin protein expressions were examined by Western blot. The distribution of CD2AP, nephrin, F-actin and tubulin in differentiated and undifferentiated podocytes was detected by laser scanning confocal microscopy. The results showed: (1) CD2AP, WT1 and nephrin were stably expressed in differentiated and undifferentiated podocytes while synaptopodin was only expressed in differentiated podocytes. (2) CD2AP and nephrin mRNA and protein expressions were up-regulated during podocyte differentiation (P<0.05). (3) CD2AP and tubulin were distributed in the cytoplasm and perinulcear region in undifferentiated podocytes, and F-actin was predominantly localized to a cortical belt and paralleled to the cell axis. Under differentiation condition, CD2AP distribution profile was presented as peripheral accumulation, tubulin took on fascicular style and F-actin extended into foot processes in podocytes. CD2AP colocalized with nephrin and F-actin in undifferentiated podocytes. (4) After transfection with CD2AP siRNA, the expression of CD2AP was partially inhibited and cell growth was arrested; Synaptopodin, the differentiation podocyte marker, was apparently down-regulated; The differentiation of podocytes was delayed. The results demonstrate that podocyte differentiation is accompanied by cytoskeleton rearrangement and cell morphology change. CD2AP might play an essential role in podocyte

Body CT (CAT Scan)

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses ... of CT Scanning of the Body? What is CT Scanning of the Body? Computed tomography, more commonly ...

Hologic QDR 2000 whole-body scans: a comparison of three combinations of scan modes and analysis software

NASA Technical Reports Server (NTRS)

Spector, E.; LeBlanc, A.; Shackelford, L.

1995-01-01

This study reports on the short-term in vivo precision and absolute measurements of three combinations of whole-body scan modes and analysis software using a Hologic QDR 2000 dual-energy X-ray densitometer. A group of 21 normal, healthy volunteers (11 male and 10 female) were scanned six times, receiving one pencil-beam and one array whole-body scan on three occasions approximately 1 week apart. The following combinations of scan modes and analysis software were used: pencil-beam scans analyzed with Hologic's standard whole-body software (PB scans); the same pencil-beam analyzed with Hologic's newer "enhanced" software (EPB scans); and array scans analyzed with the enhanced software (EA scans). Precision values (% coefficient of variation, %CV) were calculated for whole-body and regional bone mineral content (BMC), bone mineral density (BMD), fat mass, lean mass, %fat and total mass. In general, there was no significant difference among the three scan types with respect to short-term precision of BMD and only slight differences in the precision of BMC. Precision of BMC and BMD for all three scan types was excellent: < 1% CV for whole-body values, with most regional values in the 1%-2% range. Pencil-beam scans demonstrated significantly better soft tissue precision than did array scans. Precision errors for whole-body lean mass were: 0.9% (PB), 1.1% (EPB) and 1.9% (EA). Precision errors for whole-body fat mass were: 1.7% (PB), 2.4% (EPB) and 5.6% (EA). EPB precision errors were slightly higher than PB precision errors for lean, fat and %fat measurements of all regions except the head, although these differences were significant only for the fat and % fat of the arms and legs. In addition EPB precision values exhibited greater individual variability than PB precision values. Finally, absolute values of bone and soft tissue were compared among the three combinations of scan and analysis modes. BMC, BMD, fat mass, %fat and lean mass were significantly different between

Morphological changes of the hair roots in alopecia areata: a scanning electron microscopic study.

PubMed

Karashima, Tadashi; Tsuruta, Daisuke; Hamada, Takahiro; Ishii, Norito; Ono, Fumitake; Ueda, Akihiro; Abe, Toshifumi; Nakama, Takekuni; Dainichi, Teruki; Hashimoto, Takashi

2013-12-01

Alopecia areata is a chronic inflammatory condition causing non-scarring patchy hair loss. Diagnosis of alopecia areata is made by clinical observations, hair pluck test and dermoscopic signs. However, because differentiation from other alopecia diseases is occasionally difficult, an invasive diagnostic method using a punch biopsy is performed. In this study, to develop a reliable, less invasive diagnostic method for alopecia areata, we performed scanning electron microscopy of the hair roots of alopecia areata patients. This study identified four patterns of hair morphology specific to alopecia areata: (I) long tapering structure with no accumulation of scales; (II) club-shaped hair root with fine scales; (III) proximal accumulation of scales; and (IV) sharp tapering of the proximal end of hair. On the basis of these results, we can distinguish alopecia areata by scanning electron microscopic observation of the proximal end of the hair shafts. © 2013 Japanese Dermatological Association.

Rapid-scan EPR of immobilized nitroxides

NASA Astrophysics Data System (ADS)

Yu, Zhelin; Quine, Richard W.; Rinard, George A.; Tseitlin, Mark; Elajaili, Hanan; Kathirvelu, Velavan; Clouston, Laura J.; Boratyński, Przemysław J.; Rajca, Andrzej; Stein, Richard; Mchaourab, Hassane; Eaton, Sandra S.; Eaton, Gareth R.

2014-10-01

X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for 14N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for 15N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10″ magnet to reduce resistive losses in the magnet pole faces. For the same data acquisition time, the signal-to-noise for the rapid-scan absorption spectra was about an order of magnitude higher than for continuous wave first-derivative spectra recorded with modulation amplitudes that do not broaden the lineshapes.

Nanoscopium: a Scanning Hard X-ray Nanoprobe Beamline at Synchrotron Soleil

NASA Astrophysics Data System (ADS)

Somogyi, A.; Polack, F.; Moreno, T.

2010-06-01

Nanoscopium is the single scanning hard X-ray nano-probe beamline planned at SOLEIL. This ˜155 m long beamline will fully exploit the high brilliance and coherence characteristics of the X-ray beam both for diffraction limited focusing and for contrast formation. It will offer the most advanced imaging techniques in multimodal mode and will be a research tool for a wide user community working in the fields of earth-, environmental-, and life-sciences. The different μ-μnano-probe techniques offered by the beamline will permit elemental mapping at trace (ppm) levels (scanning XRF), speciation mapping (XANES), phase gradient mapping (scanning differential phase contrast), and density-contrast based imaging of internal structures (coherent diffraction imaging) in the 30 nm to 1 μm spatial resolution range, also in "in situ conditions". Nanoscopium will cover the 5-20 keV energy range. The stability of the nanobeam will be ensured by horizontally reflecting beamline optics (a sagitally and a tangentially pre-focusing mirror, horizontally reflecting monochromators) in front of the overfilled secondary source. Trade-off between high energy resolution (ΔE/E˜10-4) and high flux (1011 ph/s with ΔE/E˜10-2) will be achieved by two interchangeable monochromators (a double crystal and a double multilayer one). KB mirror and FZP lenses will be used as focusing devices. The beamline is in the design and construction phase. It is foreseen to be open for users at the beginning of 2013.

Application of Sonoelastography in Differential Diagnosis of Benign and Malignant Thyroid Nodules.

PubMed

Esfahanian, Fatemeh; Aryan, Arvin; Ghajarzadeh, Mahsa; Yazdi, Meisam Hosein; Nobakht, Nasir; Burchi, Mehdi

2016-01-01

Sonoelastography is a new ultrasound method which could be helpful to determine which thyroid nodule is malignant. We designed this study to evaluate the accuracy of sonoelastography in differentiating of benign and malignant thyroid nodules in Iranian patients. Forty thyroid nodules in forty consecutive patients who had been referred for sonography-guided fine-needle aspiration biopsy were evaluated. Gray scale ultrasound and elastosonography by real-time, freehand technique applied for all patients. Elastography findings were classified into four groups. Nodules which were classified as patterns 1 or 2 in elastogram evaluation were classified as benign and probably malignant if elastogram scans were patterns 3 and 4 of elastogram scan. Mean age ± standard deviation (SD) was 42.2 ± 12.6 years, and mean ± SD thyroid-stimulating hormone level was 1.4 ± 1.9 IU/ml. Thirty-five cases (87.5%) were female and 5 (12.5%) were male. Histological examination indicated 27 (67.5%) benign and 13 (32.5%) malignant nodules. The most elastogram score was 2 (50%) followed by score 3. The cut-off point of 2 considered as the best value to differentiate benign and malignant thyroid nodules with sensitivity and specificity of 61% and 78% (area under the curve = 0.76, 95% confidence interval: 0.6-0.92, P = 0.007). Sonoelastography could help to differentiate benign and malignant thyroid nodules. As our sample size was limited, larger studies are recommended.

Scan posture definition and hip girth measurement: the impact on clothing design and body scanning.

PubMed

Gill, Simeon; Parker, Christopher J

2017-08-01

Ergonomic measurement is central to product design and development; especially for body worn products and clothing. However, there is a large variation in measurement definitions, complicated by new body scanning technology that captures measurements in a posture different to traditional manual methods. Investigations of hip measurement definitions in current clothing measurement practices supports analysis of the effect of scan posture and hip measurement definition on the circumferences of the hip. Here, the hip girth is a key clothing measurement that is not defined in current body scanning measurement standards. Sixty-four participants were scanned in the standard scan posture of a [TC] 2 body scanner, and also in a natural posture similar to that of traditional manual measurement collection. Results indicate that scan posture affects hip girth circumferences, and that some current clothing measurement practices may not define the largest lower body circumference. Recommendations are made concerning how the hip is defined in measurement practice and within body scanning for clothing product development. Practitioner Summary: The hip girth is an important measurement in garment design, yet its measurement protocol is not currently defined. We demonstrate that body posture during body scanning affects hip circumferences, and that current clothing measurement practices may not define the largest lower body circumference. This paper also provides future measurement practice recommendations.

Scanning microarray slides.

PubMed

Ares, Manuel

2014-02-01

Here we describe some practical concerns surrounding the scanning of microarray slides that have been hybridized with fluorescent dyes. We use a laser scanner that has two lasers, each set to excite a different fluor, and separate detectors to capture emission from each fluor. The laser passes over an address (position on the scanned surface) and the detectors capture photons emitted from each address. Two superimposed image files are written that carry intensities for each channel for each pixel of the image scan. These are the raw data. Image analysis software is used to identify and summarize the intensities of the pixels that make up each spot. After comparison to background pixels, the processed intensity levels representing the gene expression measurements are associated with the identity of each spot.

Fast two-dimensional grid and transmission X-ray microscopy scanning methods for visualizing and characterizing protein crystals

PubMed Central

Wojdyla, Justyna Aleksandra; Panepucci, Ezequiel; Martiel, Isabelle; Ebner, Simon; Huang, Chia-Ying; Caffrey, Martin; Bunk, Oliver; Wang, Meitian

2016-01-01

A fast continuous grid scan protocol has been incorporated into the Swiss Light Source (SLS) data acquisition and analysis software suite on the macromolecular crystallography (MX) beamlines. Its combination with fast readout single-photon counting hybrid pixel array detectors (PILATUS and EIGER) allows for diffraction-based identification of crystal diffraction hotspots and the location and centering of membrane protein microcrystals in the lipid cubic phase (LCP) in in meso in situ serial crystallography plates and silicon nitride supports. Diffraction-based continuous grid scans with both still and oscillation images are supported. Examples that include a grid scan of a large (50 nl) LCP bolus and analysis of the resulting diffraction images are presented. Scanning transmission X-ray microscopy (STXM) complements and benefits from fast grid scanning. STXM has been demonstrated at the SLS beamline X06SA for near-zero-dose detection of protein crystals mounted on different types of sample supports at room and cryogenic temperatures. Flash-cooled crystals in nylon loops were successfully identified in differential and integrated phase images. Crystals of just 10 µm thickness were visible in integrated phase images using data collected with the EIGER detector. STXM offers a truly low-dose method for locating crystals on solid supports prior to diffraction data collection at both synchrotron microfocusing and free-electron laser X-ray facilities. PMID:27275141

Are environmental scanning units effective?

PubMed

Stubbart, C

1982-06-01

Many authorities have urged companies to set up environmental scanning to assist corporate planning. Some advocates have recommended a unit at corporate level. This would give breadth of view and penetration into the future. It would arm decision makers with accurate forecasts. The information would be broad in scope and future directed. It could provide also assumptions for long-range planning. The Fahey and King study produced a model of corporate scanning types. The data showed that environmental information was built into the plan. Though the political environment was important, scanning was inadequate. The best location for scanning was not at corporate level and most firms used irregular methods. The Thomas study concluded that effective environmental scanning was permanent and multi level and that 'best practice' was continuous scanning. In 1978 the sample organizations were revisited. Five of the twelve have not changed their practice. The factors which encouraged a continuous model were the attitudes of academics and business media, demonstrated success of the units, the right kind of personnel. Contrary influences were changes in top management, decentralization moves, resource cuts, defining the environment and its significance, the availability of scanning competent personnel, surprise itself, and the availability of alternatives e.g. external forecasts.

A low-temperature scanning tunneling microscope capable of microscopy and spectroscopy in a Bitter magnet at up to 34 T.

PubMed

Tao, W; Singh, S; Rossi, L; Gerritsen, J W; Hendriksen, B L M; Khajetoorians, A A; Christianen, P C M; Maan, J C; Zeitler, U; Bryant, B

2017-09-01

We present the design and performance of a cryogenic scanning tunneling microscope (STM) which operates inside a water-cooled Bitter magnet, which can attain a magnetic field of up to 38 T. Due to the high vibration environment generated by the magnet cooling water, a uniquely designed STM and a vibration damping system are required. The STM scan head is designed to be as compact and rigid as possible, to minimize the effect of vibrational noise as well as fit the size constraints of the Bitter magnet. The STM uses a differential screw mechanism for coarse tip-sample approach, and operates in helium exchange gas at cryogenic temperatures. The reliability and performance of the STM are demonstrated through topographic imaging and scanning tunneling spectroscopy on highly oriented pyrolytic graphite at T = 4.2 K and in magnetic fields up to 34 T.

Measuring nanometre-scale electric fields in scanning transmission electron microscopy using segmented detectors.

PubMed

Brown, H G; Shibata, N; Sasaki, H; Petersen, T C; Paganin, D M; Morgan, M J; Findlay, S D

2017-11-01

Electric field mapping using segmented detectors in the scanning transmission electron microscope has recently been achieved at the nanometre scale. However, converting these results to quantitative field measurements involves assumptions whose validity is unclear for thick specimens. We consider three approaches to quantitative reconstruction of the projected electric potential using segmented detectors: a segmented detector approximation to differential phase contrast and two variants on ptychographical reconstruction. Limitations to these approaches are also studied, particularly errors arising from detector segment size, inelastic scattering, and non-periodic boundary conditions. A simple calibration experiment is described which corrects the differential phase contrast reconstruction to give reliable quantitative results despite the finite detector segment size and the effects of plasmon scattering in thick specimens. A plasmon scattering correction to the segmented detector ptychography approaches is also given. Avoiding the imposition of periodic boundary conditions on the reconstructed projected electric potential leads to more realistic reconstructions. Copyright © 2017 Elsevier B.V. All rights reserved.

Differential Multiphoton Laser Scanning Microscopy

PubMed Central

Field, Jeffrey J.; Sheetz, Kraig E.; Chandler, Eric V.; Hoover, Erich E.; Young, Michael D.; Ding, Shi-you; Sylvester, Anne W.; Kleinfeld, David; Squier, Jeff A.

2016-01-01

Multifocal multiphoton microscopy (MMM) in the biological and medical sciences has become an important tool for obtaining high resolution images at video rates. While current implementations of MMM achieve very high frame rates, they are limited in their applicability to essentially those biological samples that exhibit little or no scattering. In this paper, we report on a method for MMM in which imaging detection is not necessary (single element point detection is implemented), and is therefore fully compatible for use in imaging through scattering media. Further, we demonstrate that this method leads to a new type of MMM wherein it is possible to simultaneously obtain multiple images and view differences in excitation parameters in a single shot. PMID:27390511

An Introduction to PunchScan

NASA Astrophysics Data System (ADS)

Popoveniuc, Stefan; Hosp, Ben

PunchScan is a precinct-read optical-scan balloting system that allows voters to take their ballot with them after scanning. This does not violate the secret ballot principle because the ballots cannot be read without secret information held by the distributed authority in charge of the election. In fact, this election authority will publish the ballots for everyone to see, allowing voters whose ballots were incorrectly omitted to complain. PunchScan vote-counting is performed in private by the election authority - who uses their secret information to decode the ballots - but is verified in public by an auditor.In this paper we describe how and why PunchScan works. We have kept most of the description at an outline level so that it may be used as a straw model of a cryptographic voting system.

ASR-9 processor augmentation card (9-PAC) phase II scan-scan correlator algorithms

DOT National Transportation Integrated Search

2001-04-26

The report documents the scan-scan correlator (tracker) algorithm developed for Phase II of the ASR-9 Processor Augmentation Card (9-PAC) project. The improved correlation and tracking algorithms in 9-PAC Phase II decrease the incidence of false-alar...

Caucasian Infants Scan Own- and Other-Race Faces Differently

PubMed Central

Wheeler, Andrea; Anzures, Gizelle; Quinn, Paul C.; Pascalis, Olivier; Omrin, Danielle S.; Lee, Kang

2011-01-01

Young infants are known to prefer own-race faces to other race faces and recognize own-race faces better than other-race faces. However, it is entirely unclear as to whether infants also attend to different parts of own- and other-race faces differently, which may provide an important clue as to how and why the own-race face recognition advantage emerges so early. The present study used eye tracking methodology to investigate whether 6- to 10-month-old Caucasian infants (N = 37) have differential scanning patterns for dynamically displayed own- and other-race faces. We found that even though infants spent a similar amount of time looking at own- and other-race faces, with increased age, infants increasingly looked longer at the eyes of own-race faces and less at the mouths of own-race faces. These findings suggest experience-based tuning of the infant's face processing system to optimally process own-race faces that are different in physiognomy from other-race faces. In addition, the present results, taken together with recent own- and other-race eye tracking findings with infants and adults, provide strong support for an enculturation hypothesis that East Asians and Westerners may be socialized to scan faces differently due to each culture's conventions regarding mutual gaze during interpersonal communication. PMID:21533235

Simulation and Characterization of a Miniaturized Scanning Electron Microscope

NASA Technical Reports Server (NTRS)

Gaskin, Jessica A.; Jerman, Gregory A.; Medley, Stephanie; Gregory, Don; Abbott, Terry O.; Sampson, Allen R.

2011-01-01

A miniaturized Scanning Electron Microscope (mSEM) for in-situ lunar investigations is being developed at NASA Marshall Space Flight Center with colleagues from the University of Alabama in Huntsville (UAH), Advanced Research Systems (ARS), the University of Tennessee in Knoxville (UTK) and Case Western Reserve University (CWRU). This effort focuses on the characterization of individual components of the mSEM and simulation of the complete system. SEMs can provide information on the size, shape, morphology and chemical composition of lunar regolith. Understanding these basic properties will allow us to better estimate the challenges associated with In-Situ Resource Utilization and to improve our basic science knowledge of the lunar surface (either precluding the need for sample return or allowing differentiation of unique samples to be returned to Earth.) The main components of the mSEM prototype includes: a cold field emission electron gun (CFEG), focusing lens, deflection/scanning system and backscatter electron detector. Of these, the electron gun development is of particular importance as it dictates much of the design of the remaining components. A CFEG was chosen for use with the lunar mSEM as its emission does not depend on heating of the tungsten emitter (lower power), it offers a long operation lifetime, is orders of magnitude brighter than tungsten hairpin guns, has a small source size and exhibits low beam energy spread.

Unique phase identification of trimetallic copper iron manganese oxygen carrier using simultaneous differential scanning calorimetry/thermogravimetric analysis during chemical looping combustion reactions with methane

DOE PAGES

Benincosa, William; Siriwardane, Ranjani; Tian, Hanjing; ...

2017-07-05

Chemical looping combustion (CLC) is a promising combustion technology that generates heat and sequestration-ready carbon dioxide that is undiluted by nitrogen from the combustion of carbonaceous fuels with an oxygen carrier, or metal oxide. This process is highly dependent on the reactivity and stability of the oxygen carrier. The development of oxygen carriers remains one of the major barriers for commercialization of CLC. Synthetic oxygen carriers, consisting of multiple metal components, have demonstrated enhanced performance and improved CLC operation compared to single metal oxides. However, identification of the complex mixed metal oxide phases that form after calcination or during CLCmore » reactions has been challenging. Without an understanding of the dominant metal oxide phase, it is difficult to determine reaction parameters and the oxygen carrier reduction pathway, which are necessary for CLC reactor design. This is particularly challenging for complex multi-component oxygen carriers such as copper iron manganese oxide (CuFeMnO 4). This study aims to differentiate the unique phase formation of a highly reactive, complex trimetallic oxygen carrier, CuFeMnO 4, from its single and bimetallic counterparts using thermochemical and reaction data obtained from simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) during temperature programmed reductions (TPR) with methane. DSC/TGA experiments during TPR with methane provides heat flow data and corresponding reaction rate data that can be used to determine reaction routes and mechanisms during methane reduction. Furthermore, non-isothermal TPR data provides the advantage of distinguishing reactions that may not be observable in isothermal analysis. The detailed thermochemical and reaction data, obtained during TPR with methane, distinguished a unique reduction pathway for CuFeMnO 4 that differed from its single and bimetallic counterparts. This is remarkable since X

Unique phase identification of trimetallic copper iron manganese oxygen carrier using simultaneous differential scanning calorimetry/thermogravimetric analysis during chemical looping combustion reactions with methane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benincosa, William; Siriwardane, Ranjani; Tian, Hanjing

Chemical looping combustion (CLC) is a promising combustion technology that generates heat and sequestration-ready carbon dioxide that is undiluted by nitrogen from the combustion of carbonaceous fuels with an oxygen carrier, or metal oxide. This process is highly dependent on the reactivity and stability of the oxygen carrier. The development of oxygen carriers remains one of the major barriers for commercialization of CLC. Synthetic oxygen carriers, consisting of multiple metal components, have demonstrated enhanced performance and improved CLC operation compared to single metal oxides. However, identification of the complex mixed metal oxide phases that form after calcination or during CLCmore » reactions has been challenging. Without an understanding of the dominant metal oxide phase, it is difficult to determine reaction parameters and the oxygen carrier reduction pathway, which are necessary for CLC reactor design. This is particularly challenging for complex multi-component oxygen carriers such as copper iron manganese oxide (CuFeMnO 4). This study aims to differentiate the unique phase formation of a highly reactive, complex trimetallic oxygen carrier, CuFeMnO 4, from its single and bimetallic counterparts using thermochemical and reaction data obtained from simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) during temperature programmed reductions (TPR) with methane. DSC/TGA experiments during TPR with methane provides heat flow data and corresponding reaction rate data that can be used to determine reaction routes and mechanisms during methane reduction. Furthermore, non-isothermal TPR data provides the advantage of distinguishing reactions that may not be observable in isothermal analysis. The detailed thermochemical and reaction data, obtained during TPR with methane, distinguished a unique reduction pathway for CuFeMnO 4 that differed from its single and bimetallic counterparts. This is remarkable since X

Mössbauer Magnetic Scan experiments

NASA Astrophysics Data System (ADS)

Pasquevich, G. A.; Mendoza Zélis, P.; Lencina, A.; Veiga, A.; Fernández van Raap, M. B.; Sánchez, F. H.

2014-06-01

We report an application of the Mössbauer Effect designed to retrieve specific information on the magnetic response of iron-containing materials. It consists in the measurement of the nuclear absorption of gamma-rays as a function of an external magnetic field for a specific nuclear transition between magnetically-split nuclear levels. The experiments, here termed Mössbauer Magnetic Scan experiments, were carried out recording the absorption of 57Fe 14.4 keV gamma-ray in α-Fe at constant Doppler energies coincident with some of the spectral lines of the magnetically split Mössbauer spectrum. Due to the dependence of the transition probabilities on the relative orientation between the nuclear magnetic moment and the gamma-ray direction, the present application results in a useful method to study the magnetic-field evolution of the distribution of atomic-magnetic-moment orientations. The proposed technique inherit from the Mössbauer Spectroscopy the chemical-element selectiveness as well as the ability to differentiate responses from iron atoms located at inequivalent site or at different phases. In this work, we show that the data analysis for these experiments depends on the sample thickness that the gamma-ray has to cross. For thin samples (i.e.samples with Mössbauer effective thicknesses lower than one) the magnetic-field dependence of the second-order-moment of the orientation distribution in the direction of the gamma ray is obtained. On the other hand, for thicker samples, although the data analysis is more complex, the dependences of the three second-order-moments of the orientation distribution are obtained. The experiments were performed on two α-Fe foils of different Mössbauer effective thicknesses. They were chosen to represent the cases of thin and thick Mössbauer absorbers. The magnetic evolution of the orientations distribution is compared with results obtained from magnetometric measurements showing a good agreement as well indicating the

Bone scanning in severe external otitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levin, W.J.; Shary, J.H. 3d.; Nichols, L.T.

1986-11-01

Technetium99 Methylene Diphosphate bone scanning has been considered an early valuable tool to diagnose necrotizing progressive malignant external otitis. However, to our knowledge, no formal studies have actually compared bone scans of otherwise young, healthy patients with severe external otitis to scans of patients with clinical presentation of malignant external otitis. Twelve patients with only severe external otitis were studied with Technetium99 Diphosphate and were compared to known cases of malignant otitis. All scans were evaluated by two neuroradiologists with no prior knowledge of the clinical status of the patients. Nine of the 12 patients had positive bone scans withmore » many scans resembling those reported with malignant external otitis. Interestingly, there was no consistent correlation between the severity of clinical presentation and the amount of Technetium uptake. These findings suggest that a positive bone scan alone should not be interpreted as indicative of malignant external otitis.« less

Differentiating oral lesions in different carcinogenesis stages with optical coherence tomography

NASA Astrophysics Data System (ADS)

Tsai, Meng-Tsan; Lee, Cheng-Kuang; Lee, Hsiang-Chieh; Chen, Hsin-Ming; Chiang, Chun-Pin; Wang, Yih-Ming; Yang, Chih-Chung

2009-07-01

A swept-source optical coherence tomography (SS-OCT) system is used to clinically scan oral lesions in different oral carcinogenesis stages, including normal oral mucosa control, mild dysplasia (MiD), moderate dysplasia (MoD), early-stage squamous cell carcinoma (ES-SCC), and well-developed SCC (WD-SCC), for diagnosis purpose. On the basis of the analyses of the SS-OCT images, the stages of dysplasia (MiD and MoD), and SCC (ES-SCC and WD-SCC) can be differentiated from normal control by evaluating the depth-dependent standard deviation (SD) values of lateral variations. In the dysplasia stage, the boundary between the epithelium (EP) and lamina propria (LP) layers can still be identified and the EP layer becomes significantly thicker than that of normal control. Also, in a certain range of the EP layer above the EP/LP boundary, the SD value becomes larger than a certain percentage of the maximum level, which is observed around the EP/LP boundary. On the other hand, in the ES-SCC and WD-SCC stages, the EP/LP boundary disappears. Because of the higher density of connective tissue papillae in the ES-SCC stage, the SD values of the slowly varying lateral scan profiles in the ES-SCC samples are significantly larger than those in the WD-SCC sample. Also, ES-SCC can be differentiated from WD-SCC by comparing the exponential decay constants of averaged A-mode scan profiles. Because of the higher tissue absorption in the WD-SCC lesion, the decay constants in the WD-SCC samples are significantly higher than those in the ES-SCC samples.

Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.

2013-12-03

For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent massmore » loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.« less

Disproportionation of a crystalline citrate salt of a developmental pharmaceutical compound: characterization of the kinetics using pH monitoring and online Raman spectroscopy plus quantitation of the crystalline free base form in binary physical mixtures using FT-Raman, XRPD and DSC.

PubMed

Skrdla, Peter J; Zhang, Dan

2014-03-01

The crystalline citrate salt (CS) of a developmental pharmaceutical compound, MK-Q, was investigated in this work from two different, but related, perspectives. In the first part of the paper, the apparent disproportionation kinetics were surveyed using two different slurry systems, one containing water and the other a pH 6.9 phosphate buffer, using time-dependent measurements of the solution pH or by acquiring online Raman spectra of the solids. While the CS is generally stable when stored as a solid under ambient conditions of temperature and humidity, its low pHmax (<3) facilitates rapid disproportionation in aqueous solution, particularly at higher pH values. The rate of disappearance of the CS was found to obey first-order (Noyes-Whitney/dissolution rate-limited) kinetics, however, the formation of the crystalline product form in the slurry system was observed to exhibit kinetics consistent with a heterogeneous nucleation-and-growth mechanism. In the second part of this paper, more sensitive offline measurements made using XRPD, DSC and FT-Raman spectroscopy were applied to the characterization of binary physical mixtures of the CS and free base (FB) crystalline forms of MK-Q to obtain a calibration curve for each technique. It was found that all calibration plots exhibited good linearity of response, with the limit of detection (LOD) for each technique estimated to be ≤7 wt% FB. While additional calibration curves would need to be constructed to allow for accurate quantitation in various slurry systems, the general feasibility of these techniques is demonstrated for detecting low levels of CS disproportionation. Copyright © 2013 Elsevier B.V. All rights reserved.

AlaScan: A Graphical User Interface for Alanine Scanning Free-Energy Calculations.

PubMed

Ramadoss, Vijayaraj; Dehez, François; Chipot, Christophe

2016-06-27

Computation of the free-energy changes that underlie molecular recognition and association has gained significant importance due to its considerable potential in drug discovery. The massive increase of computational power in recent years substantiates the application of more accurate theoretical methods for the calculation of binding free energies. The impact of such advances is the application of parent approaches, like computational alanine scanning, to investigate in silico the effect of amino-acid replacement in protein-ligand and protein-protein complexes, or probe the thermostability of individual proteins. Because human effort represents a significant cost that precludes the routine use of this form of free-energy calculations, minimizing manual intervention constitutes a stringent prerequisite for any such systematic computation. With this objective in mind, we propose a new plug-in, referred to as AlaScan, developed within the popular visualization program VMD to automate the major steps in alanine-scanning calculations, employing free-energy perturbation as implemented in the widely used molecular dynamics code NAMD. The AlaScan plug-in can be utilized upstream, to prepare input files for selected alanine mutations. It can also be utilized downstream to perform the analysis of different alanine-scanning calculations and to report the free-energy estimates in a user-friendly graphical user interface, allowing favorable mutations to be identified at a glance. The plug-in also assists the end-user in assessing the reliability of the calculation through rapid visual inspection.

Obstacles to Industrial Implementation of Scanning Systems

Treesearch

Anders Astrom; Olog Broman; John Graffman; Anders Gronlund; Armas Jappinene; Jari Luostarinen; Jan Nystrom; Daniel L. Schmoldt

1998-01-01

Initially the group discussed what is meant by scanning systems. An operational definition was adopted to consider scanning system in the current context to be nontraditional scanning. Where, traditional scanning is defined as scanning that has been industrially operational and relatively common for several years-a mature technology. For example,...

WE-EF-207-09: Single-Scan Dual-Energy CT Using Primary Modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrongolo, M; Zhu, L

Purpose: Compared with conventional CT, dual energy CT (DECT) provides better material differentiation but requires projection data with two different effective x-ray spectra. Current DECT scanners use either a two-scan setting or costly imaging components, which are not feasible or available on open-gantry cone-beam CT systems. We propose a hardware-based method which utilizes primary modulation to enable single-scan DECT on a conventional CT scanner. The CT imaging geometry of primary modulation is identical to that used in our previous method for scatter removal, making it possible for future combination with effective scatter correction on the same CT scanner. Methods: Wemore » insert an attenuation sheet with a spatially-varying pattern - primary modulator-between the x-ray source and the imaged object. During the CT scan, the modulator selectively hardens the x-ray beam at specific detector locations. Thus, the proposed method simultaneously acquires high and low energy data. High and low energy CT images are then reconstructed from projections with missing data via an iterative CT reconstruction algorithm with gradient weighting. Proof-of-concept studies are performed using a copper modulator on a cone-beam CT system. Results: Our preliminary results on the Catphan(c) 600 phantom indicate that the proposed method for single-scan DECT is able to successfully generate high-quality high and low energy CT images and distinguish different materials through basis material decomposition. By applying correction algorithms and using all of the acquired projection data, we can reconstruct a single CT image of comparable image quality to conventional CT images, i.e., without primary modulation. Conclusion: This work shows great promise in using a primary modulator to perform high-quality single-scan DECT imaging. Future studies will test method performance on anthropomorphic phantoms and perform quantitative analyses on image qualities and DECT decomposition accuracy

The use of differential scintigraphy in the clinical diagnosis of osseous and soft tissue changes affecting the diabetic foot

DOE Office of Scientific and Technical Information (OSTI.GOV)

Visser, H.J.; Jacobs, A.M.; Oloff, L.

Prompt recognition of cellulitis, osteomyelitis, diabetic osteolysis, Charcot neuroarthropathy, septic synovitis, and deep plantar abscesses in the diabetic foot is essential because the therapy is drastically different. Differential diagnosis has been greatly facilitated by recently developed scanning techniques.

Children and Adults Scan Faces of Own and Other Races Differently

PubMed Central

Hu, Chao; Wang, Qiandong; Fu, Genyue; Quinn, Paul C.; Lee, Kang

2014-01-01

Extensive behavioral and neural evidence suggests that processing of own-race faces differs from that of other-race faces in both adults and infants. However, little research has examined whether and how children scan faces of own and other races differently for face recognition. In this eye-tracking study, Chinese children aged from 4 to 7 years and Chinese adults were asked to remember Chinese and Caucasian faces. None of the participants had any direct contact with foreign individuals. Multi-method analyses of eye-tracking data revealed that regardless of age group, proportional fixation duration on the eyes of Chinese faces was significantly lower than that on the eyes of Caucasian faces, whereas proportional fixation duration on the nose and mouth of Chinese faces was significantly higher than that on the nose and mouth of Caucasian faces. In addition, the amplitude of saccades on Chinese faces was significantly lower than that on Caucasian faces, potentially reflecting finer-grained processing for own-race faces. Moreover, adults’ fixation duration/saccade numbers on the whole faces, proportional fixation percentage on the nose, proportional number of saccades between AOIs, and accuracy in recognizing faces were higher than those of children. These results together demonstrated that an abundance of visual experience with own-race faces and a lack of it with other-race faces may result in differential facial scanning in both adults and children. Furthermore, the increased experience of processing faces may result in a more holistic and advanced scanning strategy in Chinese adults. PMID:24929225

Continuous scanning mode for ptychography

DOE PAGES

Clark, Jesse N.; Huang, Xiaojing; Harder, Ross J.; ...

2014-10-15

We outline how ptychographic imaging can be performed without the need for discrete scan positions. Through an idealized experiment, we demonstrate how a discrete-position scan regime can be replaced with a continuously scanned one with suitable modification of the reconstruction scheme based on coherent modes. Thus, the impact of this is that acquisition times can be reduced, significantly aiding ptychographic imaging with x rays, electrons, or visible light.

Wide-field reflective scanning optical systems

NASA Technical Reports Server (NTRS)

Abel, I. R.

1973-01-01

Catoptric optical scanning system provides relatively fast line-scan rate for two-dimensional coverage. Rapid scan rates require low focal ratios between components and smallest possible masses. System is relatively free from monochromatic defects and chromatic aberrations.

Differentiated norepinephrine spillover in human skeletal muscle.

PubMed

Karlsson, A K; Elam, M; Lönnroth, P; Sullivan, L; Friberg, P

1997-07-01

Most neurophysiological studies have shown similar sympathetic outflow to arm and leg. However, some direct microneurographic recordings indicate differentiated sympathetic outflow to limbs both at rest and during mental stress. Hence, differentiated levels of norepinephrine (NE) spillover could prevail. By steady-state infusion of [3H]NE and body composition determination by dual-energy X-ray absorptiometry-scan, we simultaneously assessed arm and leg NE spillover related to 100 g tissue and total limb weight. NE spillover was lower in leg than arm (0.26 vs. 1.51 pmol.min-1.100 g-1, P < 0.05), and the difference remained when expressed as a function of total limb weight (66 vs. 137 pmol/min, P < 0.05). Fractional extraction of [3H]NE was similar in arm and leg. Neuronal uptake blockade by desipramine was more effective in leg than arm; fractional extraction in leg decreased by 32% (P < 0.05) but was unaltered in arm. Thus a lower NE spillover was observed from leg than arm, possibly reflecting a lower sympathetic outflow and a more neuronally dependent reuptake.

Differential Electrochemical Conductance Imaging at the Nanoscale.

PubMed

López-Martínez, Montserrat; Artés, Juan Manuel; Sarasso, Veronica; Carminati, Marco; Díez-Pérez, Ismael; Sanz, Fausto; Gorostiza, Pau

2017-09-01

Electron transfer in proteins is essential in crucial biological processes. Although the fundamental aspects of biological electron transfer are well characterized, currently there are no experimental tools to determine the atomic-scale electronic pathways in redox proteins, and thus to fully understand their outstanding efficiency and environmental adaptability. This knowledge is also required to design and optimize biomolecular electronic devices. In order to measure the local conductance of an electrode surface immersed in an electrolyte, this study builds upon the current-potential spectroscopic capacity of electrochemical scanning tunneling microscopy, by adding an alternating current modulation technique. With this setup, spatially resolved, differential electrochemical conductance images under bipotentiostatic control are recorded. Differential electrochemical conductance imaging allows visualizing the reversible oxidation of an iron electrode in borate buffer and individual azurin proteins immobilized on atomically flat gold surfaces. In particular, this method reveals submolecular regions with high conductance within the protein. The direct observation of nanoscale conduction pathways in redox proteins and complexes enables important advances in biochemistry and bionanotechnology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multislice CT of the head and body routine scans: Are scanning protocols adjusted for paediatric patients?

PubMed Central

Sun, Z; Al Ghamdi, KS; Baroum, IH

2012-01-01

Purpose: To investigate whether the multislice CT scanning protocols of head, chest and abdomen are adjusted according to patient’s age in paediatric patients. Materials and Methods: Multislice CT examination records of paediatric patients undergoing head, chest and abdomen scans from three public hospitals during a one-year period were retrospectively reviewed. Patients were categorised into the following age groups: under 4 years, 5–8 years, 9–12 years and 13–16 years, while the tube current was classified into the following ranges: < 49 mA, 50–99 mA, 100–149 mA, 150–199 mA, > 200 mA and unknown. Results: A total of 4998 patient records, comprising a combination of head, chest and abdomen CT scans, were assessed, with head CT scans representing nearly half of the total scans. Age-based adjusted CT protocols were observed in most of the scans with higher tube current setting being used with increasing age. However, a high tube current (150–199 mA) was still used in younger patients (0–8 years) undergoing head CT scans. In one hospital, CT protocols remained constant across all age groups, indicating potential overexposure to the patients. Conclusion: This analysis shows that paediatric CT scans are adjusted according to the patient’s age in most of the routine CT examinations. This indicates increased awareness regarding radiation risks associated with CT. However, high tube current settings are still used in younger patient groups, thus, optimisation of paediatric CT protocols and implementation of current guidelines, such as age-and weight-based scanning, should be recommended in daily practice. PMID:22970059

Preablation 131-I scans with SPECT/CT contribute to thyroid cancer risk stratification and 131-I therapy planning.

PubMed

Avram, Anca M; Esfandiari, Nazanene H; Wong, Ka Kit

2015-05-01

The use of preablation diagnostic radioiodine scans for risk stratification and radioiodine therapy planning for differentiated thyroid cancer (DTC) remains controversial. The objective was to assess the contribution of preablation diagnostic 131-I scans with SPECT/CT (Dx 131-I scan) to (1) the risk stratification and (2) the postoperative management of DTC. The study was designed as a prospective sequential patient series. The study was conducted at a University hospital. Three hundred twenty patients (pts) with DTC (219F; 101M, mean age 47.3 ± 16.4 y, range 10-90) were studied. Using clinical and histopathology information an endocrinologist performed risk stratification and determined postoperative management with respect to radioiodine therapy (RAI) planning. The decision to withhold or to administer RAI, and the recommended low, medium or high therapeutic 131-I activity were recorded. Dx 131-I scans were performed and interpreted by two nuclear medicine physicians as showing thyroid remnant, cervical nodal, or distant metastases. The endocrinologist then reperformed risk stratification and reformulated management after consideration of Dx 131-I scans and stimulated thyroglobulin (Tg) information. Main outcome measures were changes in risk stratification and management after Dx 131-I scans. Detection of unsuspected nodal and distant metastases and elevated stimulated Tg levels resulted in a change in the estimated risk of recurrence in 15% of patients, and management in 31% of patients, as compared to initial risk stratification and management based on histopathology alone. Both imaging data and stimulated thyroglobulin levels acquired at the time of Dx 131-I scans are consequential for 131-I therapy planning, providing information that changes risk stratification in 15% of patients as compared to recurrence risk estimation based on histopathology alone. Dx 131-I scans contribute to risk stratification by defining residual nodal and distant metastatic disease

Gallium scans in myasthenia gravis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swick, H.M.; Preston, D.F.; McQuillen, M.P.

1976-01-01

A study was conducted to determine whether /sup 67/Ga scans could be used for the detection of thymomas and to investigate the activity of the thymus gland in patients with myasthenia gravis. Scans of the anterior mediastinum proved to be a reliable way to detect thymomas. The scans were positive in eight patients including three with myasthenia gravis and histologically proved thymomas, three others with severe myasthenia gravis and thymic tumors, and two with histologically proved thymomas not associated with myasthenia. Activity on /sup 67/Ga scans was not directly related to the increased activity of the thymus gland that ismore » presumed to be associated with myasthenia gravis. (HLW)« less

Electron beams scanning: A novel method

NASA Astrophysics Data System (ADS)

Askarbioki, M.; Zarandi, M. B.; Khakshournia, S.; Shirmardi, S. P.; Sharifian, M.

2018-06-01

In this research, a spatial electron beam scanning is reported. There are various methods for ion and electron beam scanning. The best known of these methods is the wire scanning wherein the parameters of beam are measured by one or more conductive wires. This article suggests a novel method for e-beam scanning without the previous errors of old wire scanning. In this method, the techniques of atomic physics are applied so that a knife edge has a scanner role and the wires have detector roles. It will determine the 2D e-beam profile readily when the positions of the scanner and detectors are specified.

Diagnostic Accuracy of B-mode USG and Doppler Scan for Ovarian Lesions

PubMed Central

Agarwal, Vinish Kumar

2016-01-01

Introduction Ultrasonography (USG) is considered as the primary imaging modality for confirmation of ovarian mass and to differentiate them in to benign or malignant. Aim The present study was conducted with the aim to evaluate accuracy of B- mode USG and Doppler scan (Colour Doppler + Spectral Doppler) for ovarian lesions. Materials and Methods The patients included in the study were from those referred with either palpable adnexal mass or incidentally detected adnexal masses. Total 250 women were evaluated by USG, Doppler scan. Only fifty patients who had true ovarian mass intraoperatively and on histopathology were included in study, rest masses were excluded. Study parameters were morphological indexing on B- Mode USG, flow study, vessel arrangement, and vessel morphology and vessel location in Colour Doppler and resistive index and pulsatility index in spectral Doppler. Results Total 50 women were included in present study. Out of these 46% were pre-menopausal while 54% were menopaused women, 66.7% of post-menopausal women had malignant ovarian masses compared to 8.7% of premenopausal. Sensitivity, specificity, positive predictive value and negative predictive value of B-Mode USG for ovarian masses were 94.44%, 48.15%, 54.84% and 92.86% respectively, with p-value = 0.007, while sensitivity, specificity, positive predictive value and negative predictive value of Doppler scan were 85%, 90%, 85% and 90% respectively, with p-value = 0.0001. Conclusion USG and its different techniques are accepted as the primary imaging modality for early stage diagnosis of an ovarian malignancy. Statistical analysis suggests that Doppler Scan (Colour + Spectral) was more accurate (88%) than B-Mode USG (67%), but author is in view that both of these modalities should be used in conjunction to screen the ovarian lesions. PMID:27790544

Atomic resolution ultrafast scanning tunneling microscope with scan rate breaking the resonant frequency of a quartz tuning fork resonator.

PubMed

Li, Quanfeng; Lu, Qingyou

2011-05-01

We present an ultra-fast scanning tunneling microscope with atomic resolution at 26 kHz scan rate which surpasses the resonant frequency of the quartz tuning fork resonator used as the fast scan actuator. The main improvements employed in achieving this new record are (1) fully low voltage design (2) independent scan control and data acquisition, where the tuning fork (carrying a tip) is blindly driven to scan by a function generator with the scan voltage and tunneling current (I(T)) being measured as image data (this is unlike the traditional point-by-point move and measure method where data acquisition and scan control are switched many times).

Ultrafast scanning probe microscopy

DOEpatents

Weiss, Shimon; Chemla, Daniel S.; Ogletree, D. Frank; Botkin, David

1995-01-01

An ultrafast scanning probe microscopy method for achieving subpicosecond-temporal resolution and submicron-spatial resolution of an observation sample. In one embodiment of the present claimed invention, a single short optical pulse is generated and is split into first and second pulses. One of the pulses is delayed using variable time delay means. The first pulse is then directed at an observation sample located proximate to the probe of a scanning probe microscope. The scanning probe microscope produces probe-sample signals indicative of the response of the probe to characteristics of the sample. The second pulse is used to modulate the probe of the scanning probe microscope. The time delay between the first and second pulses is then varied. The probe-sample response signal is recorded at each of the various time delays created between the first and second pulses. The probe-sample response signal is then plotted as a function of time delay to produce a cross-correlation of the probe sample response. In so doing, the present invention provides simultaneous subpicosecond-temporal resolution and submicron-spatial resolution of the sample.

Full cycle rapid scan EPR deconvolution algorithm.

PubMed

Tseytlin, Mark

2017-08-01

Rapid scan electron paramagnetic resonance (RS EPR) is a continuous-wave (CW) method that combines narrowband excitation and broadband detection. Sinusoidal magnetic field scans that span the entire EPR spectrum cause electron spin excitations twice during the scan period. Periodic transient RS signals are digitized and time-averaged. Deconvolution of absorption spectrum from the measured full-cycle signal is an ill-posed problem that does not have a stable solution because the magnetic field passes the same EPR line twice per sinusoidal scan during up- and down-field passages. As a result, RS signals consist of two contributions that need to be separated and postprocessed individually. Deconvolution of either of the contributions is a well-posed problem that has a stable solution. The current version of the RS EPR algorithm solves the separation problem by cutting the full-scan signal into two half-period pieces. This imposes a constraint on the experiment; the EPR signal must completely decay by the end of each half-scan in order to not be truncated. The constraint limits the maximum scan frequency and, therefore, the RS signal-to-noise gain. Faster scans permit the use of higher excitation powers without saturating the spin system, translating into a higher EPR sensitivity. A stable, full-scan algorithm is described in this paper that does not require truncation of the periodic response. This algorithm utilizes the additive property of linear systems: the response to a sum of two inputs is equal the sum of responses to each of the inputs separately. Based on this property, the mathematical model for CW RS EPR can be replaced by that of a sum of two independent full-cycle pulsed field-modulated experiments. In each of these experiments, the excitation power equals to zero during either up- or down-field scan. The full-cycle algorithm permits approaching the upper theoretical scan frequency limit; the transient spin system response must decay within the scan

Full cycle rapid scan EPR deconvolution algorithm

NASA Astrophysics Data System (ADS)

Tseytlin, Mark

2017-08-01

Rapid scan electron paramagnetic resonance (RS EPR) is a continuous-wave (CW) method that combines narrowband excitation and broadband detection. Sinusoidal magnetic field scans that span the entire EPR spectrum cause electron spin excitations twice during the scan period. Periodic transient RS signals are digitized and time-averaged. Deconvolution of absorption spectrum from the measured full-cycle signal is an ill-posed problem that does not have a stable solution because the magnetic field passes the same EPR line twice per sinusoidal scan during up- and down-field passages. As a result, RS signals consist of two contributions that need to be separated and postprocessed individually. Deconvolution of either of the contributions is a well-posed problem that has a stable solution. The current version of the RS EPR algorithm solves the separation problem by cutting the full-scan signal into two half-period pieces. This imposes a constraint on the experiment; the EPR signal must completely decay by the end of each half-scan in order to not be truncated. The constraint limits the maximum scan frequency and, therefore, the RS signal-to-noise gain. Faster scans permit the use of higher excitation powers without saturating the spin system, translating into a higher EPR sensitivity. A stable, full-scan algorithm is described in this paper that does not require truncation of the periodic response. This algorithm utilizes the additive property of linear systems: the response to a sum of two inputs is equal the sum of responses to each of the inputs separately. Based on this property, the mathematical model for CW RS EPR can be replaced by that of a sum of two independent full-cycle pulsed field-modulated experiments. In each of these experiments, the excitation power equals to zero during either up- or down-field scan. The full-cycle algorithm permits approaching the upper theoretical scan frequency limit; the transient spin system response must decay within the scan

Alternating current scanning electrochemical microscopy with simultaneous fast-scan cyclic voltammetry.

PubMed

Koch, Jason A; Baur, Melinda B; Woodall, Erica L; Baur, John E

2012-11-06

Fast-scan cyclic voltammetry (FSCV) is combined with alternating current scanning electrochemical microscopy (AC-SECM) for simultaneous measurements of impedance and faradaic current. Scan rates of 10-1000 V s(-1) were used for voltammetry, while a high-frequency (100 kHz), low-amplitude (10 mV rms) sine wave was added to the voltammetric waveform for the ac measurement. Both a lock-in amplifier and an analog circuit were used to measure the amplitude of the resultant ac signal. The effect of the added sine wave on the voltammetry at a carbon fiber electrode was investigated and found to have negligible effect. The combined FSCV and ac measurements were used to provide simultaneous chemical and topographical information about a substrate using a single carbon fiber probe. The technique is demonstrated in living cell culture, where cellular respiration and topography were simultaneously imaged without the addition of a redox mediator. This approach promises to be useful for the topographical and multidimensional chemical imaging of substrates.

3D light scanning macrography.

PubMed

Huber, D; Keller, M; Robert, D

2001-08-01

The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences.

AVIRIS scan drive design and performance

NASA Technical Reports Server (NTRS)

Miller, D. C.

1987-01-01

The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) images the ground with an instantaneous field of view (IFOV) of 1 mrad. The IFOV is scanned 30 deg from left to right to provide the cross-track dimension of the image, while the aircraft's motion provides the along-track dimension. The scanning frequency is 12 Hz, with a scan efficiency of 70 percent. The scan mirror has an effective diameter of 5.7 in, and its positional accuracy is a small fraction of a milliradian of the nominal position-time profile. Described are the design and performance of the scan drive mechanism. Tradeoffs among various approaches are discussed, and the reasons given for the selection of the cam drive.

Dental Wear: A Scanning Electron Microscope Study

PubMed Central

Levrini, Luca; Di Benedetto, Giulia

2014-01-01

Dental wear can be differentiated into different types on the basis of morphological and etiological factors. The present research was carried out on twelve extracted human teeth with dental wear (three teeth showing each type of wear: erosion, attrition, abrasion, and abfraction) studied by scanning electron microscopy (SEM). The study aimed, through analysis of the macro- and micromorphological features of the lesions (considering the enamel, dentin, enamel prisms, dentinal tubules, and pulp), to clarify the different clinical and diagnostic presentations of dental wear and their possible significance. Our results, which confirm current knowledge, provide a complete overview of the distinctive morphology of each lesion type. It is important to identify the type of dental wear lesion in order to recognize the contributing etiological factors and, consequently, identify other more complex, nondental disorders (such as gastroesophageal reflux, eating disorders). It is clear that each type of lesion has a specific morphology and mechanism, and further clinical studies are needed to clarify the etiological processes, particularly those underlying the onset of abfraction. PMID:25548769

Model PET Scan Activity

ERIC Educational Resources Information Center

Strunk, Amber; Gazdovich, Jennifer; Redouté, Oriane; Reverte, Juan Manuel; Shelley, Samantha; Todorova, Vesela

2018-01-01

This paper provides a brief introduction to antimatter and how it, along with other modern physics topics, is utilized in positron emission tomography (PET) scans. It further describes a hands-on activity for students to help them gain an understanding of how PET scans assist in detecting cancer. Modern physics topics provide an exciting way to…

The Scanning Theremin Microscope: A Model Scanning Probe Instrument for Hands-On Activities

ERIC Educational Resources Information Center

Quardokus, Rebecca C.; Wasio, Natalie A.; Kandel, S. Alex

2014-01-01

A model scanning probe microscope, designed using similar principles of operation to research instruments, is described. Proximity sensing is done using a capacitance probe, and a mechanical linkage is used to scan this probe across surfaces. The signal is transduced as an audio tone using a heterodyne detection circuit analogous to that used in…

Application of laser scanning confocal microscopy in the soft tissue exquisite structure for 3D scan

PubMed Central

Zhang, Zhaoqiang; Ibrahim, Mohamed; Fu, Yang; Wu, Xujia; Ren, Fei; Chen, Lei

2018-01-01

Three-dimensional (3D) printing is a new developing technology for printing individualized materials swiftly and precisely in the field of biological medicine (especially tissue-engineered materials). Prior to printing, it is necessary to scan the structure of the natural biological tissue, then construct the 3D printing digital model through optimizing the scanned data. By searching the literatures, magazines at home and abroad, this article reviewed the current status, main processes and matters needing attention of confocal laser scanning microscope (LSCM) in the application of soft tissue fine structure 3D scanning, empathizing the significance of LSCM in this field. PMID:29755838

Issue Scanning: Finding the Future...Maybe.

ERIC Educational Resources Information Center

Plog, Michael; Sweeney, Jim; Weiss, Barry

Issue Scanning, sometimes called Environmental Scanning, is used in many business, government, educational, and nonprofit organizations. The technique is supposed to monitor the "pulse" of the external environment. The scanning process should lessen the randomness of the information used in decision making, and it should alert managers…

MRI Scans

MedlinePlus

Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ...

Bone Scan

MedlinePlus

... your doctor might order additional imaging called single-photon emission computerized tomography (SPECT). This imaging can help ... radioactivity from the tracers is usually completely eliminated two days after the scan. Results A doctor who ...

Gallium scan

MedlinePlus

... material called gallium and is a type of nuclear medicine exam. A related test is gallium scan ... Brown ML, Forstrom LA, et al. Society of nuclear medicine procedure guideline for gallium scintigraphy in inflammation. ...

Engineering negative differential conductance with the Cu(111) surface state.

PubMed

Heinrich, B W; Rastei, M V; Choi, D-J; Frederiksen, T; Limot, L

2011-12-09

Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate electron tunneling from a C60-terminated tip into a Cu(111) surface. Tunneling between a C60 orbital and the Shockley surface states of copper is shown to produce negative differential conductance (NDC) contrary to conventional expectations. NDC can be tuned through barrier thickness or C60 orientation up to complete extinction. The orientation dependence of NDC is a result of a symmetry matching between the molecular tip and the surface states.

Preparation and characterization of progesterone dispersions using supercritical carbon dioxide.

PubMed

Falconer, James R; Wen, Jingyuan; Zargar-Shoshtari, Sara; Chen, John J; Farid, Mohammed; Tallon, Stephen J; Alany, Raid G

2014-04-01

Supercritical fluid methods offer an alternative to conventional mixing methods, particularly for heat sensitive drugs and where an organic solvent is undesirable. To design, develop and construct a unit for the particles from a gas-saturated suspension/solution (PGSS) method and form endogenous progesterone (PGN) dispersion systems using SC-CO2. The PGN dispersions were manufactured using three selected excipients: polyethylene glycol (PEG) 400/4000 (50:50), Gelucire 44/14 and D-α-tocopheryl PEG 1000 succinate (TPGS). Semisolid dispersions of PGN prepared by PGSS method were compared to the conventional methods; comelting (CM), cosolvent (CS) and physical mixing (PM). The dispersion systems made were characterized by Raman and Fourier transform infrared (FTIR) spectroscopies, X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), PGN recovery, uniformity and in vitro dissolution, analyzed by high-performance liquid chromatography (HPLC). Raman spectra revealed no changes in the crystalline structure of PGN treated with SC-CO2 compared to that of untreated PGN. XRPD and FTIR showed the presence of peaks and bands for PGN confirming that PGN has been incorporated well with each individual excipient. All PGN dispersions prepared by the PGSS method resulted in the improvement of PGN dissolution rates compared to that prepared by the conventional methods and untreated PGN after 60 min (p value < 0.05). The novel PGN dispersions prepared by the PGSS method offer the great potential to enhance PGN dissolution rate, reduce preparation time and form stable crystalline dispersion systems over those prepared by conventional methods.

Leonardo da Vinci's drapery studies: characterization of lead white pigments by µ-XRD and 2D scanning XRF

NASA Astrophysics Data System (ADS)

Gonzalez, Victor; Calligaro, Thomas; Pichon, Laurent; Wallez, Gilles; Mottin, Bruno

2015-11-01

This work focuses on the composition and microstructure of the lead white pigment employed in a set of paintworks, using a combination of µ-XRD and 2D scanning XRF, directly applied on five drapery studies attributed to Leonardo da Vinci (1452-1519) and conserved in the Département des Arts Graphiques, Musée du Louvre and in the Musée des Beaux- Arts de Rennes. Trace elements present in the composition as well as in the lead white highlights were imaged by 2D scanning XRF. Mineral phases were determined in a fully noninvasive way using a special µ-XRD diffractometer. Phase proportions were estimated by Rietveld refinement. The analytical results obtained will contribute to differentiate lead white qualities and to highlight the artist's technique.

Bone Densitometry (Bone Density Scan)

MedlinePlus

... News Physician Resources Professions Site Index A-Z Bone Densitometry (DEXA) Bone densitometry, also called dual-energy ... limitations of DEXA Bone Densitometry? What is a Bone Density Scan (DEXA)? Bone density scanning, also called ...

Model PET Scan Activity

NASA Astrophysics Data System (ADS)

Strunk, Amber; Gazdovich, Jennifer; Redouté, Oriane; Reverte, Juan Manuel; Shelley, Samantha; Todorova, Vesela

2018-05-01

This paper provides a brief introduction to antimatter and how it, along with other modern physics topics, is utilized in positron emission tomography (PET) scans. It further describes a hands-on activity for students to help them gain an understanding of how PET scans assist in detecting cancer. Modern physics topics provide an exciting way to introduce students to current applications of physics.

Sonication-assisted synthesis of a new cationic zinc nitrate complex with a tetradentate Schiff base ligand: Crystal structure, Hirshfeld surface analysis and investigation of different parameters influence on morphological properties.

PubMed

Mousavi, S A; Montazerozohori, M; Masoudiasl, A; Mahmoudi, G; White, J M

2018-09-01

A nanostructured cationic zinc nitrate complex with a formula of [ZnLNO 3 ]NO 3 (where L = (N 2 E,N 2' E)-N 1 ,N 1' -(ethane-1,2-diyl)bis(N 2 -((E)-3-phenylallylidene)ethane-1,2-diamine)) was prepared by sonochemical process and characterized by single crystal X-ray crystallography, scanning electron microscopy (SEM), FT-IR and NMR spectroscopy and X-ray powder diffraction (XRPD). The X-ray analysis demonstrates the formation of a cationic complex that metal center is five-coordinated by four nitrogen atom from Schiff base ligand and one oxygen atom from nitrate group. The crystal packing analysis demonstrates the essential role of the nitrate groups in the organization of supramolecular structure. The morphology and size of ultrasound-assisted synthesized zinc nitrate complex have been investigated using scanning electron microscopy (SEM) by changing parameters such as the concentration of initial reactants, the sonication power and reaction temperature. In addition the calcination of zinc nitrate complex in air atmosphere led to production of zinc oxide nanoparticles. Copyright © 2018. Published by Elsevier B.V.

Device-independent color scanning

NASA Astrophysics Data System (ADS)

Burger, Rudolph E.

1993-08-01

Color calibration technology is being incorporated into both Apple and Microsoft's operating systems. These color savvy operating systems will produce a market pull towards 'smart color' scanners and printers which, in turn, will lead towards a distributed architecture for color management systems (CMS). Today's desktop scanners produce red-green-blue color signals that do not accurately describe the color of the object being scanned. Future scanners will be self-calibrating and communicate their own 'device profile' to the operating system based CMS. This paper describes some of the key technologies required for this next generation of smart color scanners. Topics covered include a comparison of colorimetric and conventional scanning technologies, and the impact of metamerism, dye fluorescence and chromatic adaptation on device independent color scanning.

PREFACE: Time-resolved scanning tunnelling microscopy Time-resolved scanning tunnelling microscopy

NASA Astrophysics Data System (ADS)

Zandvliet, Harold J. W.; Lin, Nian

2010-07-01

Scanning tunnelling microscopy has revolutionized our ability to image, manipulate, and investigate solid surfaces on the length scale of individual atoms and molecules. The strength of this technique lies in its imaging capabilities, since for many scientists 'seeing is believing'. However, scanning tunnelling microscopy also suffers from a severe limitation, namely its poor time resolution. Recording a scanning tunnelling microscopy image typically requires a few tens of seconds for a conventional scanning tunnelling microscope to a fraction of a second for a specially designed fast scanning tunnelling microscope. Designing and building such a fast scanning tunnelling microscope is a formidable task in itself and therefore, only a limited number of these microscopes have been built [1]. There is, however, another alternative route to significantly enhance the time resolution of a scanning tunnelling microscope. In this alternative method, the tunnelling current is measured as a function of time with the feedback loop switched off. The time resolution is determined by the bandwidth of the IV converter rather than the cut-off frequency of the feedback electronics. Such an approach requires a stable microscope and goes, of course, at the expense of spatial information. In this issue, we have collected a set of papers that gives an impression of the current status of this rapidly emerging field [2]. One of the very first attempts to extract information from tunnel current fluctuations was reported by Tringides' group in the mid-1990s [3]. They showed that the collective diffusion coefficient can be extracted from the autocorrelation of the time-dependent tunnelling current fluctuations produced by atom motion in and out of the tunnelling junction. In general, current-time traces provide direct information on switching/conformation rates and distributions of residence times. In the case where these processes are thermally induced it is rather straightforward to map

Water-Immersible MEMS scanning mirror designed for wide-field fast-scanning photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Yao, Junjie; Huang, Chih-Hsien; Martel, Catherine; Maslov, Konstantin I.; Wang, Lidai; Yang, Joon-Mo; Gao, Liang; Randolph, Gwendalyn; Zou, Jun; Wang, Lihong V.

2013-03-01

By offering images with high spatial resolution and unique optical absorption contrast, optical-resolution photoacoustic microscopy (OR-PAM) has gained increasing attention in biomedical research. Recent developments in OR-PAM have improved its imaging speed, but have sacrificed either the detection sensitivity or field of view or both. We have developed a wide-field fast-scanning OR-PAM by using a water-immersible MEMS scanning mirror (MEMS-ORPAM). Made of silicon with a gold coating, the MEMS mirror plate can reflect both optical and acoustic beams. Because it uses an electromagnetic driving force, the whole MEMS scanning system can be submerged in water. In MEMS-ORPAM, the optical and acoustic beams are confocally configured and simultaneously steered, which ensures uniform detection sensitivity. A B-scan imaging speed as high as 400 Hz can be achieved over a 3 mm scanning range. A diffraction-limited lateral resolution of 2.4 μm in water and a maximum imaging depth of 1.1 mm in soft tissue have been experimentally determined. Using the system, we imaged the flow dynamics of both red blood cells and carbon particles in a mouse ear in vivo. By using Evans blue dye as the contrast agent, we also imaged the flow dynamics of lymphatic vessels in a mouse tail in vivo. The results show that MEMS-OR-PAM could be a powerful tool for studying highly dynamic and time-sensitive biological phenomena.

Comparison of Laser Scanning Diagnostic Devices for Early Glaucoma Detection.

PubMed

Schulze, Andreas; Lamparter, Julia; Pfeiffer, Norbert; Berisha, Fatmire; Schmidtmann, Irene; Hoffmann, Esther M

2015-08-01

To compare the diagnostic accuracy and to evaluate the correlation of optic nerve head and retinal nerve fiber layer thickness values between Fourier-Domain optical coherence tomography (FD-OCT), confocal scanning laser ophthalmoscopy (CSLO), and scanning laser polarimetry (SLP) for early glaucoma detection. Ninety-three patients with early open-angle glaucoma, 58 patients with ocular hypertension, and 60 healthy control subjects were included in this observational, cross-sectional study. All study participants underwent FD-OCT (RTVue-100), CSLO (HRT3), and SLP (GDx VCC) imaging of the optic nerve head and the retinal nerve fiber layer. Area under the receiver operating characteristic curves (AUROC) and Bland-Altman analysis were performed. The parameters with the highest diagnostic accuracy were found for FD-OCT cup-to-disc ratio (AUROC=0.841), for SLP NFI (AUROC=0.835), and for CSLO cup-to-disc ratio (AUROC=0.789). Diagnostic accuracy of the best CSLO and SLP parameter was similar (P=0.259). There was a small statistically significant difference between the best CSLO and FD-OCT parameters for differentiating between glaucoma and healthy eyes (P=0.047). FD-OCT and SLP have a similarly good diagnostic ability to distinguish between early glaucoma and healthy subjects. The diagnostic accuracy of CSLO was comparable with SLP and marginally lower compared with FD-OCT.

Genome-wide scans for loci under selection in humans

PubMed Central

2005-01-01

Natural selection, which can be defined as the differential contribution of genetic variants to future generations, is the driving force of Darwinian evolution. Identifying regions of the human genome that have been targets of natural selection is an important step in clarifying human evolutionary history and understanding how genetic variation results in phenotypic diversity, it may also facilitate the search for complex disease genes. Technological advances in high-throughput DNA sequencing and single nucleotide polymorphism genotyping have enabled several genome-wide scans of natural selection to be undertaken. Here, some of the observations that are beginning to emerge from these studies will be reviewed, including evidence for geographically restricted selective pressures (ie local adaptation) and a relationship between genes subject to natural selection and human disease. In addition, the paper will highlight several important problems that need to be addressed in future genome-wide studies of natural selection. PMID:16004726

4D computed tomography scans for conformal thoracic treatment planning: is a single scan sufficient to capture thoracic tumor motion?

NASA Astrophysics Data System (ADS)

Tseng, Yolanda D.; Wootton, Landon; Nyflot, Matthew; Apisarnthanarax, Smith; Rengan, Ramesh; Bloch, Charles; Sandison, George; St. James, Sara

2018-01-01

Four dimensional computed tomography (4DCT) scans are routinely used in radiation therapy to determine the internal treatment volume for targets that are moving (e.g. lung tumors). The use of these studies has allowed clinicians to create target volumes based upon the motion of the tumor during the imaging study. The purpose of this work is to determine if a target volume based on a single 4DCT scan at simulation is sufficient to capture thoracic motion. Phantom studies were performed to determine expected differences between volumes contoured on 4DCT scans and those on the evaluation CT scans (slow scans). Evaluation CT scans acquired during treatment of 11 patients were compared to the 4DCT scans used for treatment planning. The images were assessed to determine if the target remained within the target volume determined during the first 4DCT scan. A total of 55 slow scans were compared to the 11 planning 4DCT scans. Small differences were observed in phantom between the 4DCT volumes and the slow scan volumes, with a maximum of 2.9%, that can be attributed to minor differences in contouring and the ability of the 4DCT scan to adequately capture motion at the apex and base of the motion trajectory. Larger differences were observed in the patients studied, up to a maximum volume difference of 33.4%. These results demonstrate that a single 4DCT scan is not adequate to capture all thoracic motion throughout treatment.

Ultrafast scanning probe microscopy

DOEpatents

Weiss, S.; Chemla, D.S.; Ogletree, D.F.; Botkin, D.

1995-05-16

An ultrafast scanning probe microscopy method is described for achieving subpicosecond-temporal resolution and submicron-spatial resolution of an observation sample. In one embodiment of the present claimed invention, a single short optical pulse is generated and is split into first and second pulses. One of the pulses is delayed using variable time delay means. The first pulse is then directed at an observation sample located proximate to the probe of a scanning probe microscope. The scanning probe microscope produces probe-sample signals indicative of the response of the probe to characteristics of the sample. The second pulse is used to modulate the probe of the scanning probe microscope. The time delay between the first and second pulses is then varied. The probe-sample response signal is recorded at each of the various time delays created between the first and second pulses. The probe-sample response signal is then plotted as a function of time delay to produce a cross-correlation of the probe sample response. In so doing, the present invention provides simultaneous subpicosecond-temporal resolution and submicron-spatial resolution of the sample. 6 Figs.

Retrospective imaging study on the diagnosis of pathological false positive iodine-131 scans in patients with thyroid cancer.

PubMed

Jia, Qiang; Meng, Zhaowei; Tan, Jian; Zhang, Guizhi; He, Yajing; Sun, Haoran; Yu, Chunshui; Li, Dong; Zheng, Wei; Wang, Renfei; Wang, Shen; Li, Xue; Zhang, Jianping; Hu, Tianpeng; Liu, N A; Upadhyaya, Arun

2015-11-01

Iodine-131 (I-131) therapy and post-therapy I-131 scanning are essential in the management of differentiated thyroid cancer (DTC). However, pathological false positive I-131 scans can lead to misdiagnosis and inappropriate I-131 treatment. This retrospective study aimed to investigate the best imaging modality for the diagnosis of pathological false positive I-131 scans in a DTC patient cohort, and to determine its incidence. DTC patient data archived from January 2008 to January 2010 was retrieved. Post-therapeutic I-131 scans were conducted and interpreted. The imaging modalities of magnetic resonance imaging (MRI), computed tomography and ultrasonography were applied and compared to check all suspected lesions. Biopsy or needle aspiration was conducted for patients who consented to the acquisition of histopathological confirmation. Data for 156 DTC patients were retrieved. Only 6 cases of pathological false-positives were found among these (incidence, 3.85%), which included 3 cases of thymic hyperplasia in the mediastinum, 1 case of pleomorphic adenoma in the parapharyngeal space and 1 case of thyroglossal duct cyst in the neck. MRI was demonstrated as the best imaging modality for diagnosis due to its superior soft tissue resolution. However, no imaging modality was able to identify the abdominal false positive-lesions observed in 2 cases, one of whom also had thymic hyperplasia. In conclusion, pathological false positive I-131 scans occurred with an incidence of 3.85%. MRI was the best imaging modality for diagnosing these pathological false-positives.

Role of color Doppler in differentiation of Graves' disease and thyroiditis in thyrotoxicosis

PubMed Central

Donkol, Ragab Hani; Nada, Aml Mohamed; Boughattas, Sami

2013-01-01

AIM: To evaluate the role of thyroid blood flow assessment by color-flow Doppler ultrasonography in the differential diagnosis of thyrotoxicosis and compare it to technetium pertechnetate thyroid scanning. METHODS: Twenty-six patients with thyrotoxicosis were included in the study. Clinical history was taken and physical examination and thyroid function tests were performed for all patients. Thyroid autoantibodies were measured. The thyroid glands of all patients were evaluated by gray scale ultrasonography for size, shape and echotexture. Color-flow Doppler ultrasonography of the thyroid tissue was performed and spectral flow analysis of both inferior thyroid arteries was assessed. Technetium99 pertechnetate scanning of the thyroid gland was done for all patients. According to thyroid scintigraphy, the patients were divided into two groups: 18 cases with Graves’ disease and 8 cases with Hashimoto’s thyroiditis. All patients had suppressed thyrotropin. The diagnosis of Graves’ disease and Hashimoto’s thyroiditis was supported by the clinical picture and follow up of patients. RESULTS: Peak systolic velocities of the inferior thyroid arteries were significantly higher in patients with Graves’ disease than in patients with thyroiditis (P = 0.004 in the right inferior thyroid artery and P = 0.001 in left inferior thyroid artery). Color-flow Doppler ultrasonography parameters demonstrated a sensitivity of 88.9% and a specificity of 87.5% in the differential diagnosis of thyrotoxicosis. CONCLUSION: Color Doppler flow of the inferior thyroid artery can be used in the differential diagnosis of thyrotoxicosis, especially when there is a contraindication of thyroid scintigraphy by radioactive material in some patients. PMID:23671754

Transverse section radionuclide scanning system

DOEpatents

Kuhl, David E.; Edwards, Roy Q.

1976-01-01

This invention provides a transverse section radionuclide scanning system for high-sensitivity quantification of brain radioactivity in cross-section picture format in order to permit accurate assessment of regional brain function localized in three-dimensions. High sensitivity crucially depends on overcoming the heretofore known raster type scanning, which requires back and forth detector movement involving dead-time or partial enclosure of the scan field. Accordingly, this invention provides a detector array having no back and forth movement by interlaced detectors that enclose the scan field and rotate as an integral unit around one axis of rotation in a slip ring that continuously transmits the detector data by means of laser emitting diodes, with the advantages that increased amounts of data can be continuously collected, processed and displayed with increased sensitivity according to a suitable computer program.

Development of surface stabilized candesartan cilexetil nanocrystals with enhanced dissolution rate, permeation rate across CaCo-2, and oral bioavailability.

PubMed

Jain, Sanyog; Reddy, Venkata Appa; Arora, Sumit; Patel, Kamlesh

2016-10-01

Candesartan cilexetil (CC), an ester prodrug of candesartan, is BCS class II drug with extremely low aqueous solubility limiting its oral bioavailability. The present research aimed to develop a nanocrystalline formulation of CC with improved saturation solubility in gastrointestinal fluids and thereby, exhibiting enhanced oral bioavailability. CC nanocrystals were prepared using a low energy antisolvent precipitation methodology. A combination of hydroxypropyl methylcellulose (HPMC) and Pluronic® F 127 (50:50 w/w) was found to be optimum for the preparation of CC nanocrystals. The particle size, polydispersity index (PDI), and zeta potential of optimized formulation was found to be 159 ± 8.1 nm, 0.177 ± 0.043, and -23.7 ± 1.02 mV, respectively. Optimized formulation was found to possess irregular, plate-like morphology as evaluated by scanning electron microscopy and crystalline as evaluated by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). A significant increase in saturation solubility and dissolution rate of the optimized nanosuspension was observed at all the tested pH conditions. Optimized CC nanocrystals exhibited a storage stability of more than 3 months when stored under cold and room temperature conditions. In vitro Caco-2 permeability further revealed that CC nanocrystals exhibited nearly 4-fold increase in permeation rate compared to the free CC. In vivo oral bioavailability studies of optimized CC nanocrystals in murine model revealed 3.8-fold increase in the oral bioavailability and twice the C max as compared with the free CC when administered orally. In conclusion, this study has established a crystalline nanosuspension formulation of CC with improved oral bioavailability in murine model. Graphical Abstract Antisolvent precipitation methodology for the preparation of Candesartan Cilexetil nanocrystals for enhanced solubility and oral bioavailability.

Effects of crystalline state and self-nanoemulsifying drug delivery system (SNEDDS) on oral bioavailability of the novel anti-HIV compound 6-benzyl-1-benzyloxymethyl-5-iodouracil in rats.

PubMed

Lu, Ying-Yuan; Dai, Wen-Bing; Wang, Xin; Wang, Xiao-Wei; Liu, Jun-Yi; Li, Pu; Lou, Ya-Qing; Lu, Chuang; Zhang, Qiang; Zhang, Guo-Liang

2018-02-01

The objective of this study was to investigate the effect of crystalline state and a formulation of self-nanoemulsifying drug delivery system (SNEDDS) on oral bioavailability of 6-benzyl-1-benzyloxymethyl-5-iodouracil (W-1), a novel non-nucleoside reverse transcriptase inhibitor, in rats. The crystalline states of W-1 were characterized by scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). The SNEDDS was formulated by medium-chain lipids, characterized by droplet particle size. The plasma concentrations of W-1 were measured by high performance liquid chromatography (HPLC). The results indicated that W-1 compound were presented as crystalline forms, A and B, the degree of crystallization in form B was higher than that in form A. The SNEDDS of W-1 displayed a significant increase in the dissolution rate than W-1 powder. Furthermore, after oral administration of W-1 (100 mg/kg), the pharmacokinetic parameters of form A, form B, and W-1 SNEDDS were as follows: AUC 0-t 526.4 ± 123.5, 305.1 ± 58.5 and 2297 ± 451 ng h/mL (p < .05, when W-1 SNEDDS were compared with either form A or form B), respectively. With SNEDDS formulation, the relative bioavailabilities were enhanced by 4.36-fold and 7.53-fold over the form A and form B of W-1, respectively. In conclusion, the present results suggested that the crystalline states of W-1 might lead to the lower oral bioavailability, and SNEDDS formulation is a promising strategy of improving bioavailability, in spite of that crystalline states usually carry small lot-to-lot variability.

Reliability of cone beam computed tomography as a biopsy-independent tool in differential diagnosis of periapical cysts and granulomas: An In vivo Study.

PubMed

Chanani, Ankit; Adhikari, Haridas Das

2017-01-01

Differential diagnosis of periapical cysts and granulomas is required as their treatment modalities are different. The aim of this study was to evaluate the efficacy of cone beam computed tomography (CBCT) in the differential diagnosis of periapical cysts from granulomas. A single-centered observational study was carried out in the Department of Conservative Dentistry and Endodontics, Dr. R. Ahmed Dental College and Hospital, using CBCT and dental operating microscope. Forty-five lesions were analyzed using CBCT scans. One evaluator analyzed each CBCT scan for the presence of the following six characteristic radiological features: cyst like-location, shape, periphery, internal structure, effect on the surrounding structures, and cortical plate perforation. Another independent evaluator analyzed the CBCT scans. This process was repeated after 6 months, and inter- and intrarater reliability of CBCT diagnoses was evaluated. Periapical surgeries were performed and tissue samples were obtained for histopathological analysis. To evaluate the efficacy, CBCT diagnoses were compared with histopathological diagnoses, and six receiver operating characteristic (ROC) curve analyses were conducted. ROC curve, Cronbach's alpha (α) test, and Cohen Kappa (κ) test were used for statistical analysis. Both inter- and intrarater reliability were excellent (α = 0.94, κ = 0.75 and 0.77, respectively). ROC curve with regard to ≥4 positive findings revealed the highest area under curve (0.66). CBCT is moderately accurate in the differential diagnosis of periapical cysts and granulomas.

A scanning tunneling microscope with a scanning range from hundreds of micrometers down to nanometer resolution.

PubMed

Kalkan, Fatih; Zaum, Christopher; Morgenstern, Karina

2012-10-01

A beetle type stage and a flexure scanning stage are combined to form a two stages scanning tunneling microscope (STM). It operates at room temperature in ultrahigh vacuum and is capable of scanning areas up to 300 μm × 450 μm down to resolution on the nanometer scale. This multi-scale STM has been designed and constructed in order to investigate prestructured metallic or semiconducting micro- and nano-structures in real space from atomic-sized structures up to the large-scale environment. The principle of the instrument is demonstrated on two different systems. Gallium nitride based micropillars demonstrate scan areas up to hundreds of micrometers; a Au(111) surface demonstrates nanometer resolution.

Anthropometric data collection of Portuguese children using 3D body scanning: considerations about the scanning booth

NASA Astrophysics Data System (ADS)

de Campos, R.; Carvalho, M. A.; Lopes, H. P.; Xu, B.

2017-10-01

This paper presents some considerations regarding the scanning booth used in an anthropometric study done with a 3D body scanning technology. The data collected is part of a Ph.D. study conducted in Textile Engineering at University of Minho in Portugal, which aims to develop clothing for overweight and obese Portuguese children aged 2-11 years, of both genders. The challenges faced during data collection are described, and modifications of the scanning booth are proposed. It is possible to conclude that the importance of the scanning booth is key to an efficient anthropometric data collection, including the growth of this technology in the garment industry, Universities Research Institutes involved with anthropometric studies.

Relations between scanning and recognition of own- and other-race faces in 6- and 9-month-old infants.

PubMed

Liu, Shaoying; Quinn, Paul C; Xiao, Naiqi G; Wu, Zhijun; Liu, Guangxi; Lee, Kang

2018-06-01

Infants typically see more own-race faces than other-race faces. Existing evidence shows that this difference in face race experience has profound consequences for face processing: as early as 6 months of age, infants scan own- and other-race faces differently and display superior recognition for own- relative to other-race faces. However, it is unclear whether scanning of own-race faces is related to the own-race recognition advantage in infants. To bridge this gap in the literature, the current study used eye tracking to investigate the relation between own-race face scanning and recognition in 6- and 9-month-old Asian infants (N = 82). The infants were familiarized with dynamic own- and other-race faces, and then their face recognition was tested with static face images. Both age groups recognized own- but not other-race faces. Also, regardless of race, the more infants scanned the eyes of the novel versus familiar faces at test, the better their face-recognition performance. In addition, both 6- and 9-month-olds fixated significantly longer on the nose of own-race faces, and greater fixation on the nose during test trials correlated positively with individual novelty preference scores in the own- but not other-race condition. The results suggest that some aspects of the relation between recognition and scanning are independent of differential experience with face race, whereas other aspects are affected by such experience. More broadly, the findings imply that scanning and recognition may become linked during infancy at least in part through the influence of perceptual experience. © 2018 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

SU-E-T-133: Dosimetric Impact of Scan Orientation Relative to Target Motion During Spot Scanning Proton Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoker, J; Summers, P; Li, X

2014-06-01

Purpose: This study seeks to evaluate the dosimetric effects of intra-fraction motion during spot scanning proton beam therapy as a function of beam-scan orientation and target motion amplitude. Method: Multiple 4DCT scans were collected of a dynamic anthropomorphic phantom mimicking respiration amplitudes of 0 (static), 0.5, 1.0, and 1.5 cm. A spot-scanning treatment plan was developed on the maximum intensity projection image set, using an inverse-planning approach. Dynamic phantom motion was continuous throughout treatment plan delivery.The target nodule was designed to accommodate film and thermoluminescent dosimeters (TLD). Film and TLDs were uniquely labeled by location within the target. The phantommore » was localized on the treatment table using the clinically available orthogonal kV on-board imaging device. Film inserts provided data for dose uniformity; TLDs provided a 3% precision estimate of absolute dose. An inhouse script was developed to modify the delivery order of the beam spots, to orient the scanning direction parallel or perpendicular to target motion.TLD detector characterization and analysis was performed by the Imaging and Radiation Oncology Core group (IROC)-Houston. Film inserts, exhibiting a spatial resolution of 1mm, were analyzed to determine dose homogeneity within the radiation target. Results: Parallel scanning and target motions exhibited reduced target dose heterogeneity, relative to perpendicular scanning orientation. The average percent deviation in absolute dose for the motion deliveries relative to the static delivery was 4.9±1.1% for parallel scanning, and 11.7±3.5% (p<<0.05) for perpendicularly oriented scanning. Individual delivery dose deviations were not necessarily correlated to amplitude of motion for either scan orientation. Conclusions: Results demonstrate a quantifiable difference in dose heterogeneity as a function of scan orientation, more so than target amplitude. Comparison to the analyzed planar dose of a

Methods to Differentiate Radiation Necrosis and Recurrent Disease in Gliomas

NASA Astrophysics Data System (ADS)

Ewell, Lars

2007-03-01

Given the difficulty in differentiating Radiation Induced Necrosis (RIN) and recurrent disease in glioma patients using conventional techniques (CT scans, MRI scans), researchers have looked for different imaging modalities. Among these different modalities are Diffusion Weighted Magnetic Resonance Imaging (DWMRI) and Magnetic Resonance Spectroscopy (MRS). In DWMRI, an Apparent Diffusion Coefficient (ADC) is calculated for a Region Of Interest (ROI), and then monitored over time (longitudinally). In the brain, different anatomical features can complicate the interpretation of ADCs. In particular, the density and spatial variation of the cerebral spinal fluid filled fissures known as sulci can influence how a change in an ADC is explained. We have used the covariance of pixel intensity in T1 weighted MRI scans to study how intra-patient and inter-patient sulci density varies, and will present these results. MRS uses the shift in the MR signal due to the local chemical environment to determine the concentration of brain metabolites like choline and creatin. The ratio of metabolites such as these has been shown to have the power to discriminate between RIN and recurrent disease in glioma patients. At our institution, we have initiated a protocol whereby we will use DWMRI and MRS to study how best to utilize these complimentary forms of imaging.

Compact ultra-fast vertical nanopositioner for improving scanning probe microscope scan speed

NASA Astrophysics Data System (ADS)

Kenton, Brian J.; Fleming, Andrew J.; Leang, Kam K.

2011-12-01

The mechanical design of a high-bandwidth, short-range vertical positioning stage is described for integration with a commercial scanning probe microscope (SPM) for dual-stage actuation to significantly improve scanning performance. The vertical motion of the sample platform is driven by a stiff and compact piezo-stack actuator and guided by a novel circular flexure to minimize undesirable mechanical resonances that can limit the performance of the vertical feedback control loop. Finite element analysis is performed to study the key issues that affect performance. To relax the need for properly securing the stage to a working surface, such as a laboratory workbench, an inertial cancellation scheme is utilized. The measured dominant unloaded mechanical resonance of a prototype stage is above 150 kHz and the travel range is approximately 1.56 μm. The high-bandwidth stage is experimentally evaluated with a basic commercial SPM, and results show over 25-times improvement in the scanning performance.

Negative differential resistance in electron tunneling in ultrathin films near the two-dimensional limit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batabyal, R.; Abdul Wasey, A. H. M.; Mahato, J. C.

We report on our observation of negative differential resistance (NDR) in electron tunneling conductance in atomic-scale ultrathin Ag films on Si(111) substrates. NDR was observed by scanning tunneling spectroscopy measurements. The tunneling conductance depends on the electronic local density of states (LDOS) of the sample. We show that the sample bias voltage, at which negative differential resistance and peak negative conductance occur, depends on the film thickness. This can be understood from the variation in the LDOS of the Ag films as a function of film thickness down to the two-dimensional limit of one atomic layer. First principles density functionalmore » theory calculations have been used to explain the results.« less

Design concept for improved photo-scan tube

NASA Technical Reports Server (NTRS)

Malling, L. R.

1967-01-01

Conceptual photo-scan tube avoids complexity of internal beam scanning and beam-current adjustment by optical scan readout. It differs from a conventional image orthicon in its use of an external oscilloscope tube.

Investigating the Effects of Loading Factors on the In Vitro Pharmaceutical Performance of Mesoporous Materials as Drug Carriers for Ibuprofen

PubMed Central

Lai, Junmin; Lin, Wu; Scholes, Peter; Li, Mingzhong

2017-01-01

The aim of the study was to investigate the effects of the loading factors, i.e., the initial drug loading concentration and the ratio of the drug to carriers, on the in vitro pharmaceutical performance of drug-loaded mesoporous systems. Ibuprofen (IBU) was used as a model drug, and two non-ordered mesoporous materials of commercial silica Syloid® 244FP (S244FP) and Neusilin® US2 (NS2) were selected in the study. The IBU-loaded mesoporous samples were prepared by a solvent immersion method with a rotary evaporation drying technique and characterized by polarized light microscopy (PLM), Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). Dissolution experiments were performed in simulated gastric media at 37 °C under non-sink conditions. The concentration of IBU in solution was determined by HPLC. The study showed that the dissolution rate of IBU can be improved significantly using the mesoporous S224FP carriers due to the conversion of crystalline IBU into the amorphous form. Both of the loading factors affected the IBU dissolution kinetics. Due to the molecular interaction between the IBU and NS2 carriers, the loading factors had little effects on the drug release kinetics with incomplete drug desorption recovery and insignificant dissolution enhancement. Care and extensive evaluation must therefore be taken when mesoporous materials are chosen as carrier delivery systems. PMID:28772509

Polymorphic Transformation of Indomethacin during Hot Melt Extrusion Granulation: Process and Dissolution Control.

PubMed

Xu, Ting; Nahar, Kajalajit; Dave, Rutesh; Bates, Simon; Morris, Kenneth

2018-05-10

To study and elucidate the effect of the intensity and duration of processing stresses on the possible solid-state changes during a hot melt extrusion granulation process. Blends of α-indomethacin and PEG 3350 (w/w 4:1) were granulated using various screw sizes/designs on the melt extruder under different temperature regimes. Differential Scanning Calorimetry and X-ray Powder Diffraction were employed for characterization. The dissolution behavior of the pure polymorphs and the resulting granules was determined using in-situ fiber optic UV testing system. An XRPD quantitation method using Excel full pattern fitting was developed to determine the concentration of each constituent (amorphous, α and γ indomethacin and PEG) in samples collected from each functioning zone and in granules. Analysis of in-process samples and granules revealed that higher temperature (≥130°C) and shear stress accelerated the process induced phase transitions from amorphous and/or the α form to γ indomethacin during heating stage. However, rapid cooling resulted in an increased percentage of the α form allowing isolation of the meta-stable form. By determining the conditions that either prevent or facilitate process induced transformations of IMC polymorphs during melt granulation, a design space was developed to control the polymorph present in the resulting granules. This represents the conditions necessary to balance the thermodynamic relationships between the polymorphs of the IMC system and the kinetics of the possible transformations as a function of the processing stresses.

PSIDD (2): A Prototype Post-Scan Interactive Data Display System for Detailed Analysis of Ultrasonic Scans

NASA Technical Reports Server (NTRS)

Cao, Wei; Roth, Don J.

1997-01-01

This article presents the description of PSIDD(2), a post-scan interactive data display system for ultrasonic contact scan and single measurement analysis. PSIDD(2) was developed in conjunction with ASTM standards for ultrasonic velocity and attenuation coefficient contact measurements. This system has been upgraded from its original version PSIDD(1) and improvements are described in this article. PSIDD(2) implements a comparison mode where the display of time domain waveforms and ultrasonic properties versus frequency can be shown for up to five scan points on one plot. This allows the rapid contrasting of sample areas exhibiting different ultrasonic properties as initially indicated by the ultrasonic contact scan image. This improvement plus additional features to be described in the article greatly facilitate material microstructural appraisal.

TU-F-18A-06: Dual Energy CT Using One Full Scan and a Second Scan with Very Few Projections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, T; Zhu, L

Purpose: The conventional dual energy CT (DECT) requires two full CT scans at different energy levels, resulting in dose increase as well as imaging errors from patient motion between the two scans. To shorten the scan time of DECT and thus overcome these drawbacks, we propose a new DECT algorithm using one full scan and a second scan with very few projections by preserving structural information. Methods: We first reconstruct a CT image on the full scan using a standard filtered-backprojection (FBP) algorithm. We then use a compressed sensing (CS) based iterative algorithm on the second scan for reconstruction frommore » very few projections. The edges extracted from the first scan are used as weights in the Objectives: function of the CS-based reconstruction to substantially improve the image quality of CT reconstruction. The basis material images are then obtained by an iterative image-domain decomposition method and an electron density map is finally calculated. The proposed method is evaluated on phantoms. Results: On the Catphan 600 phantom, the CT reconstruction mean error using the proposed method on 20 and 5 projections are 4.76% and 5.02%, respectively. Compared with conventional iterative reconstruction, the proposed edge weighting preserves object structures and achieves a better spatial resolution. With basis materials of Iodine and Teflon, our method on 20 projections obtains similar quality of decomposed material images compared with FBP on a full scan and the mean error of electron density in the selected regions of interest is 0.29%. Conclusion: We propose an effective method for reducing projections and therefore scan time in DECT. We show that a full scan plus a 20-projection scan are sufficient to provide DECT images and electron density with similar quality compared with two full scans. Our future work includes more phantom studies to validate the performance of our method.« less

Use of technetium-99m methylene diphosphonate and gallium-67 citrate scans after intraarticular injection of Staphylococcus aureus into knee joints of rabbits with chronic antigen-induced arthritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahowald, M.L.; Raskind, J.R.; Peterson, L.

1986-08-01

Numerous clinical studies have questioned the ability of radionuclide scans to differentiate septic from aseptic joint inflammation. A clinical study may not be able to document an underlying disease process or duration of infection and, thus, may make conclusions about the accuracy of scan interpretations open to debate. In this study, the Dumonde-Glynn model of antigen-induced arthritis in rabbits was used as the experimental model to study technetium and gallium scans in Staphylococcus aureus infection of arthritic and normal joints. Gallium scans were negative in normal rabbits, usually negative in antigen-induced arthritis, but positive in septic arthritis. The bone scanmore » was usually negative in early infection but positive in late septic arthritis, a finding reflecting greater penetration of bacteria into subchondral bone because of the underlying inflammatory process.« less

Investigation of the nanoscale two-component ZnS-ZnO heterostructures by means of HR-TEM and X-ray based analysis

NASA Astrophysics Data System (ADS)

Pankin, I. A.; Polozhentsev, O. E.; Soldatov, M. A.; Bugaev, A. L.; Tsaturyan, A.; Lomachenko, K. A.; Guda, A. A.; Budnyk, A. P.; Lamberti, C.; Soldatov, A. V.

2018-06-01

This article is devoted to the spectroscopic characterization of ZnS-ZnO nanoscale heterostructures synthesized by the microwave-assisted solvothermal method. The synthesized samples were investigated by means of X-ray powder diffraction (XRPD), high energy resolution fluorescence detected X-ray absorption near-edge-structure (HERFD-XANES) spectroscopy, valence-to-core X-ray emission spectroscopy (VtC-XES) and high resolution transmission electron microscopy (HR-TEM) as well as energy dispersive X-ray spectroscopy (EDX). The average crystallite size estimated by the broadening of XRPD peaks increases from 2.7 nm to 3.7 nm in the temperature range from 100 °C to 150 °C. HR-TEM images show that nanoparticles are arranged in aggregates with the 60-200 nm size. Theoretical estimation shows that the systems synthesized at higher temperatures more prone to the agglomeration. The full profile Reitveld analysis of XRPD data reveals the formation of hexagonal zinc sulfide structure, whereas electron diffraction data reveal also the formation of cubic zinc sulfide and claim the polymorphous character of the system. High energy resolution Zn K-edge XANES data unambiguously demonstrate the presence of a certain amount of the zinc oxide which is likely to have an amorphous structure and could not be detected by XRPD. Qualitative analysis of XANES data allows deriving ZnS/ZnO ratio as a function of synthesis temperature. EDX analysis depicts homogeneous distribution of ZnS and amorphous ZnO phases across the conglomerates. A complementary element-selective valence to core X-ray emission spectroscopy evidences formation of two-component system and confirms estimations of ZnS/ZnO fractions obtained by linear combination fit of XANES data.

The combination of scanning electron and scanning probe microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapozhnikov, I. D.; Gorbenko, O. M., E-mail: gorolga64@gmail.com; Felshtyn, M. L.

2016-06-17

We suggest the SPM module to combine SEM and SPM methods for studying surfaces. The module is based on the original mechanical moving and scanning system. The examples of studies of the steel surface microstructure in both SEM and SPM modes are presented.

Scan converting video tape recorder

NASA Technical Reports Server (NTRS)

Holt, N. I. (Inventor)

1971-01-01

A video tape recorder is disclosed of sufficient bandwidth to record monochrome television signals or standard NTSC field sequential color at current European and American standards. The system includes scan conversion means for instantaneous playback at scanning standards different from those at which the recording is being made.

[Patients treated for differentiated thyroid cancer with negative 131I whole-body scans and elevated thyroglobulin levels: a possible course].

PubMed

Gutiérrez Cardo, A L; Rodríguez Rodríguez, J R; Borrego Dorado, I; Navarro González, E; Tirado Hospital, J L; Vázquez Albertino, R

2007-01-01

To verify the existence of patients with treated differentiated thyroid cancer (DTC) with negative 131I whole-body scanning (WBS) and high serum thyroglobulin (Tg) in the follow-up who evolve towards normalization without other therapy interventions. Retrospective revision of the periodic examinations established in the protocol for patients with DTC, analyzing the levels of Tg found with IRMA annually in those with hormonal treatment and every 1-5 years in absence of previous hormonal treatment to WBS. Minimum surveillance of 2 years. Those who had elevated levels of Tg and WBS and other negative imaging tests in their course were selected. The characteristics of the patients selected were analysed in those whose Tg levels evolved to normalization without specific medical or surgical treatment (Group I) and those who did not reach normalization of Tg (Group II). A total of 130 patients (17.93 %) with high levels of Tg and negative WBS were detected. Group I: 31 patients (4.28 %), 11 men and 20 women; average age at the moment of the diagnosis of 33.4 years (rank: 5-60); average surveillance: 12.4 years (+/- 7.4). 27 papillary and 4 follicular carcinoma. Average ablation dose: 3.260 GBq (88,1 mCi); average total I131 dose: 6.850 GBq (185.13 mCi). Tg normalization average time: 8.2 years. Group II: 99 patients (13.65 %), 27 men and 72 women. Average age of 40.4 years (rank: 7-76). Average surveillance: 9.8 years. 86 papillary and 13 follicular carcinoma. Average ablation dose: 3.266 GBq (88.28 mCi); average total 131I dose: 9.363 GBq (253,06 mCi). Two of the patients in group I had negative PET-FDG. There were 13 patients in whom progressive reduction of the levels of thyroglobulin without reaching normalization with negative PET-FDG was detected. In patients with radiated DTC, deferred normalization of the levels of the serum thyroglobulin is possible. Empirical treatments cannot be considered the only factor that contributes to this result, which can occur without

Structural rearrangements in chloroplast thylakoid membranes revealed by differential scanning calorimetry and circular dichroism spectroscopy. Thermo-optic effect.

PubMed

Dobrikova, Anelia G; Várkonyi, Zsuzsanna; Krumova, Sashka B; Kovács, László; Kostov, Georgi K; Todinova, Svetla J; Busheva, Mira C; Taneva, Stefka G; Garab, Gyozo

2003-09-30

The thermo-optic mechanism in thylakoid membranes was earlier identified by measuring the thermal and light stabilities of pigment arrays with different levels of structural complexity [Cseh, Z., et al. (2000) Biochemistry 39, 15250-15257]. (According to the thermo-optic mechanism, fast local thermal transients, arising from the dissipation of excess, photosynthetically not used, excitation energy, induce elementary structural changes due to the "built-in" thermal instabilities of the given structural units.) The same mechanism was found to be responsible for the light-induced trimer-to-monomer transition in LHCII, the main chlorophyll a/b light-harvesting antenna of photosystem II (PSII) [Garab, G., et al. (2002) Biochemistry 41, 15121-15129]. In this paper, differential scanning calorimetry (DSC) and circular dichroism (CD) spectroscopy on thylakoid membranes of barley and pea are used to correlate the thermo-optically inducible structural changes with well-discernible calorimetric transitions. The thylakoid membranes exhibited six major DSC bands, with maxima between about 43 and 87 degrees C. The heat sorption curves were analyzed both by mathematical deconvolution of the overall endotherm and by a successive annealing procedure; these yielded similar thermodynamic parameters, transition temperature and calorimetric enthalpy. A systematic comparison of the DSC and CD data on samples with different levels of complexity revealed that the heat-induced disassembly of chirally organized macrodomains contributes profoundly to the first endothermic event, a weak and broad DSC band between 43 and 48 degrees C. Similarly to the main macrodomain-associated CD signals, this low enthalpy band could be diminished by prolonged photoinhibitory preillumination, the extent of which depended on the temperature of preillumination. By means of nondenaturing, "green" gel electrophoresis and CD fingerprinting, it is shown that the second main endotherm, around 60 degrees C

A hybrid scanning mode for fast scanning ion conductance microscopy (SICM) imaging

PubMed Central

Zhukov, Alex; Richards, Owen; Ostanin, Victor; Korchev, Yuri; Klenerman, David

2012-01-01

We have developed a new method of controlling the pipette for scanning ion conductance microscopy to obtain high-resolution images faster. The method keeps the pipette close to the surface during a single line scan but does not follow the exact surface topography, which is calculated by using the ion current. Using an FPGA platform we demonstrate this new method on model test samples and then on live cells. This method will be particularly useful to follow changes occurring on relatively flat regions of the cell surface at high spatial and temporal resolutions. PMID:22902298

The application of dermal papillary rings in dermatology by in vivo confocal laser scanning microscopy

NASA Astrophysics Data System (ADS)

Xiang, W. Z.; Xu, A. E.; Xu, J.; Bi, Z. G.; Shang, Y. B.; Ren, Q. S.

2010-08-01

Confocal laser scanning microscopy (CLSM) allows noninvasive visualization of human skin in vivo, without needing to fix or section the tissue. Melanocytes and pigmented keratinocytes at the level of the basal layer form bright dermal papillary rings which are readily amenable to identify in confocal images. Our purpose was to explore the role of dermal papillary rings in assessment of lesion location, the diagnosis, differential diagnosis of lesions and assessment of therapeutic efficacy by in vivo CLSM. Seventy-one patients were imaged with the VivaScope 1500 reflectance confocal microscope provided by Lucid, Inc. The results indicate that dermal papillary rings can assess the location of lesion; the application of dermal papillary rings can provide diagnostic support and differential diagnosis for vitiligo, nevus depigmentosus, tinea versicolor, halo nevus, common nevi, and assess the therapeutic efficacy of NBUVB phototherapy plus topical 0.1 percent tacrolimus ointment for vitiligo. In conclusion, our findings indicate that the dermal papillary rings play an important role in the assessment the location of lesion, diagnosis, differential diagnosis of lesions and assessment of therapeutic efficacy by in vivo CLSM. CLSM may be a promising tool for noninvasive examination in dermatology. However, larger studies are needed to expand the application of dermal papillary rings in dermatology.

The Enhancement of 3D Scans Depth Resolution Obtained by Confocal Scanning of Porous Materials

NASA Astrophysics Data System (ADS)

Martisek, Dalibor; Prochazkova, Jana

2017-12-01

The 3D reconstruction of simple structured materials using a confocal microscope is widely used in many different areas including civil engineering. Nonetheless, scans of porous materials such as concrete or cement paste are highly problematic. The well-known problem of these scans is low depth resolution in comparison to the horizontal and vertical resolution. The degradation of the image depth resolution is caused by systematic errors and especially by different random events. Our method is focused on the elimination of such random events, mainly the additive noise. We use an averaging method based on the Lindeberg-Lévy theorem that improves the final depth resolution to a level comparable with horizontal and vertical resolution. Moreover, using the least square method, we also precisely determine the limit value of a depth resolution. Therefore, we can continuously evaluate the difference between current resolution and the optimal one. This substantially simplifies the scanning process because the operator can easily determine the required number of scans.

Position-sensitive scanning fluorescence correlation spectroscopy.

PubMed

Skinner, Joseph P; Chen, Yan; Müller, Joachim D

2005-08-01

Fluorescence correlation spectroscopy (FCS) uses a stationary laser beam to illuminate a small sample volume and analyze the temporal behavior of the fluorescence fluctuations within the stationary observation volume. In contrast, scanning FCS (SFCS) collects the fluorescence signal from a moving observation volume by scanning the laser beam. The fluctuations now contain both temporal and spatial information about the sample. To access the spatial information we synchronize scanning and data acquisition. Synchronization allows us to evaluate correlations for every position along the scanned trajectory. We use a circular scan trajectory in this study. Because the scan radius is constant, the phase angle is sufficient to characterize the position of the beam. We introduce position-sensitive SFCS (PSFCS), where correlations are calculated as a function of lag time and phase. We present the theory of PSFCS and derive expressions for diffusion, diffusion in the presence of flow, and for immobilization. To test PSFCS we compare experimental data with theory. We determine the direction and speed of a flowing dye solution and the position of an immobilized particle. To demonstrate the feasibility of the technique for applications in living cells we present data of enhanced green fluorescent protein measured in the nucleus of COS cells.

Implementation of a CT Scan Practice Guideline for Pediatric Trauma Patients Reduces Unnecessary Scans Without Impacting Outcomes.

PubMed

McGrew, Patrick R; Chestovich, Paul J; Fisher, Jay D; Kuhls, Deborah A; Fraser, Douglas R; Patel, Purvi P; Katona, Chad W; Saquib, Syed; Fildes, John J

2018-05-04

Computed Tomography (CT) scans are useful in the evaluation of trauma patients, but are costly and pose risks from ionizing radiation in children. Recent literature has demonstrated the utility of CT scan guidelines in the management of pediatric trauma. This study objective is to review our treatment of pediatric blunt trauma patients and evaluate CT utilization before and after CT-guideline implementation. Our Pediatric Level 2 Trauma Center (TC) implemented a CT scan practice guideline for pediatric trauma patients in March 2014. The guideline recommended for or against CT of the head and abdomen/pelvis utilizing published criteria from the Pediatric Emergency Care and Research Network (PECARN). There was no chest CT guideline. We reviewed all pediatric trauma patients for CT scans obtained during initial evaluation before and after guideline implementation, excluding inpatient scans. The Trauma Registry Database was queried to include all pediatric (age<15) trauma patients seen in our TC from 2010-2016, excluding penetrating mechanism and deaths in the TC. Scans were considered positive if organ injury was detected. Primary outcome was the proportion of patients undergoing CT and percent positive CTs. Secondary outcomes were hospital length of stay (LOS), readmissions, and mortality. Categorical and continuous variables were analyzed with Chi-square and Wilcoxon rank-sum tests, respectively. P<0.05 was considered significant. We identified 1934 patients: 1106 pre- and 828 post-guideline. Absolute reductions in head, chest, and abdomen/pelvis CT scans were 17.7%, 11.5%, and 18.8% respectively (p<0.001). Percent positive head CTs were equivalent, but percent positive chest and abdomen CT increased after implementation. Secondary outcomes were unchanged. Implementation of a pediatric CT guideline significantly decreases CT utilization, reducing the radiation exposure without a difference in outcome. Trauma centers treating pediatric patients should adopt similar

Scanning electron microscopy of Ancylostoma spp. dog infective larvae captured and destroyed by the nematophagous fungus Duddingtonia flagrans.

PubMed

Maciel, A S; Araújo, J V; Campos, A K; Benjamin, L A; Freitas, L G

2009-06-01

The interaction between the nematode-trapping fungus Duddingtonia flagrans (isolate CG768) against Ancylostoma spp. dog infective larvae (L(3)) was evaluated by means of scanning electron microscopy. Adhesive network trap formation was observed 6h after the beginning of the interaction, and the capture of Ancylostoma spp. L(3) was observed 8h after the inoculation these larvae on the cellulose membranes colonized by the fungus. Scanning electron micrographs were taken at 0, 12, 24, 36 and 48 h, where 0 is the time when Ancylostoma spp. L(3) was first captured by the fungus. Details of the capture structure formed by the fungus were described. Nematophagous Fungus Helper Bacteria (NHB) were found at interactions points between the D. flagrans and Ancylostoma spp. L(3). The cuticle penetration by the differentiated fungal hyphae with the exit of nematode internal contents was observed 36 h after the capture. Ancylostoma spp. L(3) were completely destroyed after 48 h of interaction with the fungus. The scanning electron microscopy technique was efficient on the study of this interaction, showing that the nematode-trapping fungus D. flagrans (isolate CG768) is a potential exterminator of Ancylostoma spp. L(3).

Defect scanning technology in the works

Treesearch

Philip A. Araman; R. Conners

1994-01-01

This article describes the defect scanning technology being developed by Virginia Tech and U.S. Forest Service scientists in Blacksburg, Virginia to scan full sized hardwood lumber at industrial speeds.

Technical errors in planar bone scanning.

PubMed

Naddaf, Sleiman Y; Collier, B David; Elgazzar, Abdelhamid H; Khalil, Magdy M

2004-09-01

Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

Vector generator scan converter

DOEpatents

Moore, James M.; Leighton, James F.

1990-01-01

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

Vector generator scan converter

DOEpatents

Moore, J.M.; Leighton, J.F.

1988-02-05

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

Scanning ultrafast electron microscopy.

PubMed

Yang, Ding-Shyue; Mohammed, Omar F; Zewail, Ahmed H

2010-08-24

Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.

Scanning ultrafast electron microscopy

PubMed Central

Yang, Ding-Shyue; Mohammed, Omar F.; Zewail, Ahmed H.

2010-01-01

Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability. PMID:20696933

Thermal radiation scanning tunnelling microscopy

NASA Astrophysics Data System (ADS)

de Wilde, Yannick; Formanek, Florian; Carminati, Rémi; Gralak, Boris; Lemoine, Paul-Arthur; Joulain, Karl; Mulet, Jean-Philippe; Chen, Yong; Greffet, Jean-Jacques

2006-12-01

In standard near-field scanning optical microscopy (NSOM), a subwavelength probe acts as an optical `stethoscope' to map the near field produced at the sample surface by external illumination. This technique has been applied using visible, infrared, terahertz and gigahertz radiation to illuminate the sample, providing a resolution well beyond the diffraction limit. NSOM is well suited to study surface waves such as surface plasmons or surface-phonon polaritons. Using an aperture NSOM with visible laser illumination, a near-field interference pattern around a corral structure has been observed, whose features were similar to the scanning tunnelling microscope image of the electronic waves in a quantum corral. Here we describe an infrared NSOM that operates without any external illumination: it is a near-field analogue of a night-vision camera, making use of the thermal infrared evanescent fields emitted by the surface, and behaves as an optical scanning tunnelling microscope. We therefore term this instrument a `thermal radiation scanning tunnelling microscope' (TRSTM). We show the first TRSTM images of thermally excited surface plasmons, and demonstrate spatial coherence effects in near-field thermal emission.

Reliability of cone beam computed tomography as a biopsy-independent tool in differential diagnosis of periapical cysts and granulomas: An In vivo Study

PubMed Central

Chanani, Ankit; Adhikari, Haridas Das

2017-01-01

Background: Differential diagnosis of periapical cysts and granulomas is required as their treatment modalities are different. Aim: The aim of this study was to evaluate the efficacy of cone beam computed tomography (CBCT) in the differential diagnosis of periapical cysts from granulomas. Settings and Design: A single-centered observational study was carried out in the Department of Conservative Dentistry and Endodontics, Dr. R. Ahmed Dental College and Hospital, using CBCT and dental operating microscope. Methods: Forty-five lesions were analyzed using CBCT scans. One evaluator analyzed each CBCT scan for the presence of the following six characteristic radiological features: cyst like-location, shape, periphery, internal structure, effect on the surrounding structures, and cortical plate perforation. Another independent evaluator analyzed the CBCT scans. This process was repeated after 6 months, and inter- and intrarater reliability of CBCT diagnoses was evaluated. Periapical surgeries were performed and tissue samples were obtained for histopathological analysis. To evaluate the efficacy, CBCT diagnoses were compared with histopathological diagnoses, and six receiver operating characteristic (ROC) curve analyses were conducted. Statistical Analysis Used: ROC curve, Cronbach's alpha (α) test, and Cohen Kappa (κ) test were used for statistical analysis. Results: Both inter- and intrarater reliability were excellent (α = 0.94, κ = 0.75 and 0.77, respectively). ROC curve with regard to ≥4 positive findings revealed the highest area under curve (0.66). Conclusion: CBCT is moderately accurate in the differential diagnosis of periapical cysts and granulomas. PMID:29386780

The need for environmental horizon scanning.

PubMed

Sutherland, William J; Woodroof, Harry J