Zn-site Substitution Effect in YbCo2Zn20

NASA Astrophysics Data System (ADS)

Kobayashi, Riki; Takamura, Haruki; Higa, Yasuyuki; Ikeda, Yoichi; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Yoshizawa, Hideki; Aso, Naofumi

2017-04-01

We have investigated the substitution effect of YbCo2(Zn1-xTx)20 (T = Cu, Ga, and Cd) systems by using the experiments of X-ray powder diffraction (XRPD), specific heat, magnetic susceptibility, magnetization, and electrical resistivity in order to find out a material that approaches a quantum critical point by chemical pressure. The XRPD and electrical resistivity measurements clarify that the Cu-substitution makes the lattice constants shrink and keeps the magnetic electrical resistivity high, while the Ga- and the Cd-substitution show opposite relation of the Cu-substitution. However, we could not detect clear substitution effect in the specific heat, magnetic susceptibility, and magnetization measurements of Cu-substitution system within our experiments. It is necessary that to study the Cu-substitution samples that have higher x value at lower temperature.

The effect of chemical modification on the physico-chemical characteristics of halloysite: FTIR, XRF, and XRD studies

NASA Astrophysics Data System (ADS)

Szczepanik, Beata; Słomkiewicz, Piotr; Garnuszek, Magdalena; Czech, Kamil; Banaś, Dariusz; Kubala-Kukuś, Aldona; Stabrawa, Ilona

2015-03-01

The effect of chemical modification of halloysite from a Polish strip mine "Dunino" on the chemical composition and structure of this clay mineral was studied using infrared spectroscopy (ATR FT-IR), wavelength dispersive X-ray fluorescence (WDXRF), and X-ray powder diffraction (XRPD) methods. The results obtained by the WDXRF technique confirm that the content of silica and alumina was the highest for bleached halloysite samples and the lowest for acid-treated halloysite. A higher content of Fe2O3 in comparison to halloysite samples coming from other countries was observed for raw halloysite samples. XRPD diffraction pattern obtained for raw halloysite confirmed the presence of halloysite, kaolinite, hematite, and calcite minerals in the sample. Bleaching the halloysite removes (or significantly reduces) the content of other minerals present in the raw halloysite. The FT-IR spectra of the studied halloysite samples show in the 3700-3600 cm-1 region well-defined hydroxyl stretching bands characteristic for the kaolin-group minerals and bands associated with the vibrations of the aluminium-silicon skeleton in the 1400-1000 cm-1 region. Modifying halloysite with 4-chloro-aniline causes successive incorporation of amine into the BH sample.

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.

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

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.

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, resulted in a preferential loss of form II (compared to form I). Loss was greater at 30 degrees C/75% RH than at 20 degrees C/75% RH. Form II was also preferentially lost under low humidity conditions created by a saturated solution of potassium carbonate (45% RH) at the elevated temperature of 42 degrees C. This environment was shown to be acidic.

Macroscopic X-ray Powder Diffraction Scanning: Possibilities for Quantitative and Depth-Selective Parchment Analysis.

PubMed

Vanmeert, Frederik; De Nolf, Wout; Dik, Joris; Janssens, Koen

2018-06-05

At or below the surface of painted works of art, valuable information is present that provides insights into an object's past, such as the artist's technique and the creative process that was followed or its conservation history but also on its current state of preservation. Various noninvasive techniques have been developed over the past 2 decades that can probe this information either locally (via point analysis) or on a macroscopic scale (e.g., full-field imaging and raster scanning). Recently macroscopic X-ray powder diffraction (MA-XRPD) mapping using laboratory X-ray sources was developed. This method can visualize highly specific chemical distributions at the macroscale (dm 2 ). In this work we demonstrate the synergy between the quantitative aspects of powder diffraction and the noninvasive scanning capability of MA-XRPD highlighting the potential of the method to reveal new types of information. Quantitative data derived from a 15th/16th century illuminated sheet of parchment revealed three lead white pigments with different hydrocerussite-cerussite compositions in specific pictorial elements, while quantification analysis of impurities in the blue azurite pigment revealed two distinct azurite types: one rich in barite and one in quartz. Furthermore, on the same artifact, the depth-selective possibilities of the method that stem from an exploitation of the shift of the measured diffraction peaks with respect to reference data are highlighted. The influence of different experimental parameters on the depth-selective analysis results is briefly discussed. Promising stratigraphic information could be obtained, even though the analysis is hampered by not completely understood variations in the unit cell dimensions of the crystalline pigment phases.

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.

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.

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.

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.

Probing Pharmaceutical Mixtures during Milling: The Potency of Low-Frequency Raman Spectroscopy in Identifying Disorder.

PubMed

Walker, Greg; Römann, Philipp; Poller, Bettina; Löbmann, Korbinian; Grohganz, Holger; Rooney, Jeremy S; Huff, Gregory S; Smith, Geoffrey P S; Rades, Thomas; Gordon, Keith C; Strachan, Clare J; Fraser-Miller, Sara J

2017-12-04

This study uses a multimodal analytical approach to evaluate the rates of (co)amorphization of milled drug and excipient and the effectiveness of different analytical methods in detecting these changes. Indomethacin and tryptophan were the model substances, and the analytical methods included low-frequency Raman spectroscopy (785 nm excitation and capable of measuring both low- (10 to 250 cm -1 ) and midfrequency (450 to 1800 cm -1 ) regimes, and a 830 nm system (5 to 250 cm -1 )), conventional (200-3000 cm -1 ) Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRPD). The kinetics of amorphization were found to be faster for the mixture, and indeed, for indomethacin, only partial amorphization occurred (after 360 min of milling). Each technique was capable of identifying the transformations, but some, such as low-frequency Raman spectroscopy and XRPD, provided less ambiguous signatures than the midvibrational frequency techniques (conventional Raman and FTIR). The low-frequency Raman spectra showed intense phonon mode bands for the crystalline and cocrystalline samples that could be used as a sensitive probe of order. Multivariate analysis has been used to further interpret the spectral changes. Overall, this study demonstrates the potential of low-frequency Raman spectroscopy, which has several practical advantages over XRPD, for probing (dis-)order during pharmaceutical processing, showcasing its potential for future development, and implementation as an in-line process monitoring method.

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

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.

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.

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.

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.

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.

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.

Restricting the high-temperature growth of nanocrystalline tin oxide

NASA Astrophysics Data System (ADS)

Savin, S.; Chadwick, A. V.

2003-01-01

The sensitivity of tin oxide is dependent on various factors, one of which is the grain size. Three methods have been investigated with the aim of stabilising the grain size in the nanometer range, namely; (i) encapsulation within a silica matrix, (ii) coating the crystallites with hexamethyldisilazane and (iii) pinning the grain boundaries with a second metal oxide nanocrystal. The resulting materials have been characterised by X-ray powder diffraction (XRPD), Extended X-ray absorption fine structure (EXAFS) and conductivity measurements.

Synthesis and anti-lung cancer activity of a novel arsenomolybdate compound

NASA Astrophysics Data System (ADS)

Zhu, Tian-Tian; Wang, Juan; Chen, Song-Hu

2017-12-01

The new compound based on Wells-Dawson-type arsenomolybdate: [{Cu10(pz)11Cl4}{As2IIIAs2VMo6VMo12VIO62}]·H2O (1) has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, X-ray powder diffraction (XRPD), XPS spectroscopy and thermogravimetric analysis (TG). Compound 1 is consisted of two As caps Wells-dawson-type arsenomolybdate and {Cu10(py)11} complexes by chloride bridge. In addition, the antitumor effects of the title compound 1 were studied on three human lung cancer cells (A549, SK-LU-1 and SW1573). The results showed that compared with the positive reference drug carboplatin, compound 1 displayed efficient antitumor activity.

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.

Host-guest interaction of ZnBDC-MOF + doxorubicin: A theoretical and experimental study

NASA Astrophysics Data System (ADS)

Vasconcelos, Iane B.; Wanderley, Kaline A.; Rodrigues, Nailton M.; da Costa, Nivan B.; Freire, Ricardo O.; Junior, Severino A.

2017-03-01

The incorporation of drugs in biodegradable polymeric particles is one of many processes that controllably and significantly increase their release and action. In this paper, we describe the synthesis and physicochemical characterization of ZnBDC-MOF + doxorubicin (DOXO@ZnBDC) and the system's effectiveness in the sustained release of the drug doxorubicin. An experimental and theoretical study is presented of the interaction between the [Zn(BDC)(H2O)2]n MOF and the drug doxorubicin (DOXO). The synthesis was characterized by elemental analysis and X-ray powder diffraction (XRPD). The experimental incorporation was accomplished and analyzed by Fourier transform infrared spectroscopy (FTIR), XRPD and UV-Vis (ultraviolet-visible) spectrophotometry. Based on an analysis of the doxorubicin release profile, our results suggest that the drug delivery system showed slower release than other systems under development. Studies of cytotoxicity by the MTT method showed good results for the system developed with antineoplastic doxorubicin, and together with the other results of this study, suggest the successful development of a MOF-based drug delivery system.

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.

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.

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.

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.

Structure of N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide by combined X-ray powder diffraction, 13C solid-state NMR and molecular modelling.

PubMed

Hangan, Adriana; Borodi, Gheorghe; Filip, Xenia; Tripon, Carmen; Morari, Cristian; Oprean, Luminita; Filip, Claudiu

2010-12-01

The crystal structure solution of the title compound is determined from microcrystalline powder using a multi-technique approach that combines X-ray powder diffraction (XRPD) data analysis based on direct-space methods with information from (13)C solid-state NMR (SSNMR), and molecular modelling using the GIPAW (gauge including projector augmented-wave) method. The space group is Pbca with one molecule in the asymmetric unit. The proposed methodology proves very useful for unambiguously characterizing the supramolecular arrangement adopted by the N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide molecules in the crystal, which consists of extended double strands held together by C-H···π non-covalent interactions.

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 Elsevier B.V. All rights reserved.

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.

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 processing. It was possible to produce and control the crystallinity, morphology, and aerodynamic properties of HC particles with the SEDS technique. This method may be useful for the processing of inhalation powders.

Fast surface crystallization of amorphous griseofulvin below T g.

PubMed

Zhu, Lei; Jona, Janan; Nagapudi, Karthik; Wu, Tian

2010-08-01

To study crystal growth rates of amorphous griseofulvin (GSF) below its glass transition temperature (T (g)) and the effect of surface crystallization on the overall crystallization kinetics of amorphous GSF. Amorphous GSF was generated by melt quenching. Surface and bulk crystal growth rates were determined using polarized light microscope. X-ray powder diffraction (XRPD) and Raman microscopy were used to identify the polymorph of the crystals. Crystallization kinetics of amorphous GSF powder stored at 40 degrees C (T (g)-48 degrees C) and room temperature (T (g)-66 degrees C) was monitored using XRPD. Crystal growth at the surface of amorphous GSF is 10- to 100-fold faster than that in the bulk. The surface crystal growth can be suppressed by an ultrathin gold coating. Below T (g), the crystallization of amorphous GSF powder was biphasic with a rapid initial crystallization stage dominated by the surface crystallization and a slow or suspended late stage controlled by the bulk crystallization. GSF exhibits the fastest surface crystallization kinetics among the known amorphous pharmaceutical solids. Well below T (g), surface crystallization dominated the overall crystallization kinetics of amorphous GSF powder. Thus, surface crystallization should be distinguished from bulk crystallization in studying, modeling and controlling the crystallization of amorphous solids.

Molecular structure of hybrid imino-chalcone in the solid state: X-ray diffraction, spectroscopy study and third-order nonlinear optical properties

NASA Astrophysics Data System (ADS)

Custodio, J. M. F.; Santos, F. G.; Vaz, W. F.; Cunha, C. E. P.; Silveira, R. G.; Anjos, M. M.; Campos, C. E. M.; Oliveira, G. R.; Martins, F. T.; da Silva, C. C.; Valverde, C.; Baseia, B.; Napolitano, H. B.

2018-04-01

A comprehensive structural study of the compound (2E)-1-((E)-4-(4-methoxybenzylideneamino)phenyl)-3-(4-methoxyphenyl)prop-2-en-1-one was carried out in this work. Single crystal X-ray diffraction (SCXRD), X-ray powder diffraction (XRPD), NMR, Raman and Infrared spectroscopies, and DFT calculations were performed for characterization of this iminochalcone hybrid. Intermolecular interactions were described by Hirshfeld surface analysis derived from crystal structure. Reactivity and intramolecular charge transfer were investigated using the frontier molecular orbitals and molecular electrostatic potential. In addition, we have calculated the Nonlinear Optical Properties at the CAM-B3LYP/6-311+g(d) level of theory in the presence of different solvents (gas-phase, acetone, chloroform, dichloromethane, dimethyl sulfoxide, ethanol, methanol, and water), being found meaningful NLO parameters for our compound. At last, there is a good agreement between calculated and experimental IR spectrum, allowing the assignment of some of normal vibrational modes of the iminochalcone hybrid.

Molecular structure studies of (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol

PubMed Central

Zhang, Tao; Paluch, Krzysztof; Scalabrino, Gaia; Frankish, Neil; Healy, Anne-Marie; Sheridan, Helen

2015-01-01

The single enantiomer (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol (2), has recently been synthesized and isolated from its corresponding diastereoisomer (1). The molecular and crystal structures of this novel compound have been fully analyzed. The relative and absolute configurations have been determined by using a combination of analytical tools including X-ray crystallography, X-ray Powder Diffraction (XRPD) analysis and Nuclear Magnetic Resonance (NMR) spectroscopy. PMID:25750458

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.

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.

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).

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.

An Investigation into the Polymorphism and Crystallization of Levetiracetam and the Stability of its Solid Form.

PubMed

Xu, Kailin; Xiong, Xinnuo; Guo, Liuqi; Wang, Lili; Li, Shanshan; Tang, Peixiao; Yan, Jin; Wu, Di; Li, Hui

2015-12-01

Levetiracetam (LEV) crystals were prepared using different solvents at different temperatures. The LEV crystals were systematically characterized by X-ray powder diffraction (XRPD) and morphological analysis. The results indicated that many kinds of crystal habits exist in a solid form of LEV. To investigate the effects of LEV concentration, crystallization temperature, and crystallization type on crystallization and solid phase transformation of LEV, multiple methods were performed for LEV aqueous solution to determine if a new solid form exists in solid-state LEV. However, XRPD data demonstrate that the LEV solid forms possess same spatial arrangements that are similar to the original solid form. This result indicates that the LEV concentration, crystallization temperature, and crystallization type in aqueous solution have no influence on the crystallization and solid phase transformation of LEV. Moreover, crystallization by sublimation, melt cooling, and quench cooling, as well as mechanical effect, did not result in the formation of new LEV solid state. During melt cooling, the transformation of solid form LEV is a direct process from melting amorphous phase to the original LEV crystal phase, and the conversion rate is very quick. In addition, stability investigation manifested that LEV solid state is very stable under various conditions. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Raman, SEM-EDS and XRPD investigations on pre-Columbian Central America "estucado" pottery

NASA Astrophysics Data System (ADS)

Casanova Municchia, Annalaura; Micheli, Mario; Ricci, Maria Antonietta; Toledo, Michelle; Bellatreccia, Fabio; Lo Mastro, Sergio; Sodo, Armida

2016-03-01

Seventeen different colored fragments from six selected pre-Columbian estucado ceramics from El Salvador have been investigated by Raman spectroscopy, scanning electron microscope coupled to an energy dispersive spectrometer (SEM/EDS) and X-ray powder diffraction (XRPD). The peculiarity of this kind of ceramics consist of the unusual presence of a white engobe, traditionally termed stucco, between the ceramic body and the decoration elements, hence the name estucado ceramics. The aim of this work was to study the unusual manufacturing technique and to identify the chemical composition of the engobe and of the pigment palette. The results showed that the stucco layer is made of clay (kaolinite) with traces of titanium oxide (anatase). Remarkably, this is the same composition of the white pigments used for the decoration layer, thus excluding an early use of natural titanium oxide as a white pigment in the estucado productions as suggested in previous investigations. Moreover, the presence of kaolinite and anatase both in the stucco and in the decoration layer suggests a cold-working or low temperature technique. The red, yellow and green decorations were realized by the use of natural ochre, while in all the blue and gray decorations Maya blue pigment was identified. Finally, an amorphous carbon pigment of vegetal origin and manganese oxide were used to obtain black pigments.

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 dissolution rate of all co-amorphous drug-amino acid mixtures was significantly increased over that of the respective crystalline and amorphous pure drugs. Amino acids thus appear as promising excipients to solve challenges connected with the stability and dissolution of amorphous drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

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

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.

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.

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.

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.

Aging-driven decomposition in zolpidem hemitartrate hemihydrate and the single-crystal structure of its decomposition products.

PubMed

Vega, Daniel R; Baggio, Ricardo; Roca, Mariana; Tombari, Dora

2011-04-01

The "aging-driven" decomposition of zolpidem hemitartrate hemihydrate (form A) has been followed by X-ray powder diffraction (XRPD), and the crystal and molecular structures of the decomposition products studied by single-crystal methods. The process is very similar to the "thermally driven" one, recently described in the literature for form E (Halasz and Dinnebier. 2010. J Pharm Sci 99(2): 871-874), resulting in a two-phase system: the neutral free base (common to both decomposition processes) and, in the present case, a novel zolpidem tartrate monohydrate, unique to the "aging-driven" decomposition. Our room-temperature single-crystal analysis gives for the free base comparable results as the high-temperature XRPD ones already reported by Halasz and Dinnebier: orthorhombic, Pcba, a = 9.6360(10) Å, b = 18.2690(5) Å, c = 18.4980(11) Å, and V = 3256.4(4) Å(3) . The unreported zolpidem tartrate monohydrate instead crystallizes in monoclinic P21 , which, for comparison purposes, we treated in the nonstandard setting P1121 with a = 20.7582(9) Å, b = 15.2331(5) Å, c = 7.2420(2) Å, γ = 90.826(2)°, and V = 2289.73(14) Å(3) . The structure presents two complete moieties in the asymmetric unit (z = 4, z' = 2). The different phases obtained in both decompositions are readily explained, considering the diverse genesis of both processes. Copyright © 2010 Wiley-Liss, Inc.

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

Liu Yingya; Grzywa, Maciej; Weil, Matthias

A novel metal-organic framework (MOF) based on a tetranuclear copper cluster and a linear organic ligand formulated as [Cu{sub 4}OCl{sub 6}(DABCO){sub 2}].0.5DABCO.4CH{sub 3}OH (denoted as MFU-5, MFU=Metal-Organic Framework, Ulm University; DABCO=1,4-diazabicyclo[2.2.2]octane), was prepared via solvothermal synthesis. In contrast with common MOF synthesis strategies, MFU-5 is assembled from pre-defined molecular secondary building units, i.e. {l_brace}Cu{sub 4}OCl{sub 6}{r_brace} moieties, which become the nodes of the coordination framework. The title compound was characterized by single crystal X-ray diffraction, variable temperature powder diffraction (VT-XRPD), thermal analysis, as well as IR- and UV/Vis spectroscopy. Crystal data for MFU-5: hexagonal, P6/mcc (no. 192), a=25.645(9), c=17.105(11) A,more » V=9742(8) A{sup 3}, Z=12, 1690 structure factors, R[F{sup 2}>2sigma(F{sup 2})]=0.049. MFU-5 is a 3D metal-organic framework with 1D channels running along the c-axis hosting DABCO and methanol solvent molecules. The framework displays a zeolite-like structure constructed from mso cages, which represents the composite building units in the zeolites SSF, MSO and SZR. Two-fold interpenetration is observed between these building units. TG/DTA-MS and VT-XRPD characterization reveal a stepwise release of methanol and DABCO molecules upon heating, eventually resulting in a structural change into a non-porous material. - Graphical abstract: The metal-organic framework [Cu{sub 4}OCl{sub 6}(DABCO){sub 2}].0.5DABCO.4CH{sub 3}OH (MFU-5) is constructed from a molecular precursor containing {l_brace}Cu{sub 4}OCl{sub 6}{r_brace} secondary building units which become cross-linked into a 3D zeolite-type network with hexagonal symmetry by linear DABCO ligands (DABCO=1,4-diazabicyclo[2.2.2]octane).« less

Determination of residual solvents and investigation of their effect on ampicillin trihydrate crystal structure.

PubMed

Nojavan, Saeed; Ghassempour, Alireza; Bashour, Yosef; Darbandi, Masoud Khalilian; Ahmadi, Seyyed Hamid

2005-01-04

In the present work, the relationship between residual solvents concentration and ampicillin trihydrate crystals stability has been investigated. The amounts of residual solvents determined by GC, X-ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR) were used for characterization of solid state. The obtained results have shown good relationship between concentration of methylene chloride (as a critical residue solvent) and degree of ampicillin trihydrate crystallinity. As with the increasing methylene chloride concentration in the sample the degree of crystallinity decreased after stability test. From this relationship, critical concentration of methylene chloride into the ampicillin trihydrate is obtained and the results can be used for improving the large-scale production of ampicillin trihydrate.

Impact of drying on pore structures in ettringite-rich cements

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

Galan, I., E-mail: isabelgalan@abdn.ac.uk; Beltagui, H.; García-Maté, M.

Drying techniques affect the properties of cement pastes to varying extents. The effect of different drying techniques on calcium sulfoaluminate-based (C$A) cements and their constituent phases is reported for a range of simulated and commercial C$A pastes which are benchmarked against an OPC paste. The recommended methodologies used to dry samples were identified from the literature and include D-drying and solvent exchange. These methods were used in conjunction with mercury intrusion porosimetry (MIP) and X-ray powder diffraction (XRPD) measurements to assess the changes in pore structure and the damage to crystalline phases, respectively. D-drying and isopropanol exchange are the mostmore » satisfactory and least damaging methods for drying C$A based pastes.« less

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.

Tandem transmission/reflection mode XRD instrument including XRF for in situ measurement of Martian rocks and soils

NASA Astrophysics Data System (ADS)

Delhez, Robert; Van der Gaast, S. J.; Wielders, Arno; de Boer, J. L.; Helmholdt, R. B.; van Mechelen, J.; Reiss, C.; Woning, L.; Schenk, H.

2003-02-01

The mineralogy of the surface material of Mars is the key to disclose its present and past life and climates. Clay mineral species, carbonates, and ice (water and CO2) are and/or contain their witnesses. X-ray powder diffraction (XRPD) is the most powerful analytical method to identify and quantitatively characterize minerals in complex mixtures. This paper discusses the development of a working model of an instrument consisting of a reflection mode diffractometer and a transmission mode CCD-XRPD instrument, combined with an XRF module. The CCD-XRD/XRF instrument is analogous to the instrument for Mars missions developed by Sarrazin et al. (1998). This part of the tandem instrument enables "quick and dirty" analysis of powdered (!) matter to monitor semi-quantitatively the presence of clay minerals as a group, carbonates, and ices and yields semi-quantitative chemical information from X-ray fluorescence (XRF). The reflection mode instrument (i) enables in-situ measurements of rocks and soils and quantitative information on the compounds identified, (ii) has a high resolution and reveals large spacings for accurate identification, in particular of clay mineral species, and (iii) the shape of the line profiles observed reveals the kind and approximate amounts of lattice imperfections present. It will be shown that the information obtained with the reflection mode diffractometer is crucial for finding signs of life and changes in the climate on Mars. Obviously this instrument can also be used for other extra-terrestrial research.

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.

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.

Systematic variations in sinter mineralogy, microtexture and diagenesis in modern siliceous hot springs: Clues for interpreting depositional conditions in ancient deposits

NASA Astrophysics Data System (ADS)

Mills, V. W.; Farmer, J. D.; Ruff, S. W.; Nunez, J.; Jahnke, L. L.

2011-12-01

The deposits of siliceous hydrothermal springs are known to capture and preserve a wide range of microbial fossil information. The recent discovery of hydrothermal silica at Home Plate, Columbia Hills, Mars has once again raised interest in the potential importance of ancient spring sinters as targets for future astrobiological mission to Mars. To create additional context information to support future in situ missions to Mars, we have documented systematic changes in the mineralogy and microtexture of modern siliceous hot spring deposits, observed along gradients in temperature, pH and flow velocity. Specific objectives are to: 1) identify chemical and physical factors that promote early diagenetic transformations of amorphous silica (opal-A), to progressively more ordered and crystalline phases (cristobalite, tridymite and quartz); 2) determine the composition and abundance of minor mineral phases, especially clays, in relationship to pH, temperature and paragenesis; and 3) to assess the usefulness of sinter mineralogy and microtexture in reconstructing the paleoenvironmental records preserved in ancient deposits. Study sites for acidic (pH 2-5) sinters included Nymph Creek, located in the Norris Geyser Basin of Yellowstone National Park (YNP). Active alkaline (pH 7-10) springs included Rabbit Creek, Steep Cone and Mound Spring located in the Lower Geyser Basin, YNP. Field measurements in active springs included pH, temperature and flow velocity, along with general microfacies assignments. To better constrain types and rates of silica diagenesis, the study also sampled older (Holocene-Pleistocene-aged) deposits. Laboratory analyses included X-ray powder diffraction (XRPD), thermal infrared spectroscopy (TIR) and thin section petrography for characterizing sinter microtextures and for placing mineral phases (identified by XRPD and TIR) into a time-ordered diagenetic framework. In analyzing the phyllosilicates present in sinters, we applied clay separation and glycolization methods, with XRPD. Results indicate that all of the acidic sinters we studied showed more extensive early diagenetic ordering of silica phases (opal-A to cristobalite and quartz) than the comparable microfacies of alkaline-neutral sinters. Clay analyses showed no evidence for smectitic (expansive) clays, but kaolin family clays (dickite, kaolinite and halloysite) were present in both acidic and alkaline sinters. The microfacies distribution observed for clays suggests: 1) dickite being more abundant in higher temperature (near-vent) microfacies, 2) kaolinite dominating mid-temperature outflow channels, slope and upper distal apron microfacies, and 3) halloysite being restricted to lower distal apron-marsh microfacies transitions. Future work will expand clay analyses to apply near-IR spectroscopy to a broader range of samples to assess the consistency with patterns suggested from XRPD.

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.

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

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

An XRPD and EPR spectroscopy study of microcrystalline calcite bioprecipitated by Bacillus subtilis

NASA Astrophysics Data System (ADS)

Perito, B.; Romanelli, M.; Buccianti, A.; Passaponti, M.; Montegrossi, G.; Di Benedetto, F.

2018-05-01

We report in this study the first XRPD and EPR spectroscopy characterisation of a biogenic calcite, obtained from the activity of the bacterium Bacillus subtilis. Microcrystalline calcite powders obtained from bacterial culture in a suitable precipitation liquid medium were analysed without further manipulation. Both techniques reveal unusual parameters, closely related to the biological source of the mineral, i.e., to the bioprecipitation process and in particular to the organic matrix observed inside calcite. In detail, XRPD analysis revealed that bacterial calcite has slightly higher c/a lattice parameters ratio than abiotic calcite. This correlation was already noticed in microcrystalline calcite samples grown by bio-mineralisation processes, but it had never been previously verified for bacterial biocalcites. EPR spectroscopy evidenced an anomalously large value of W 6, a parameter that can be linked to occupation by different chemical species in the next nearest neighbouring sites. This parameter allows to clearly distinguish bacterial and abiotic calcite. This latter achievement was obtained after having reduced the parameters space into an unbiased Euclidean one, through an isometric log-ratio transformation. We conclude that this approach enables the coupled use of XRPD and EPR for identifying the traces of bacterial activity in fossil carbonate deposits.

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 thermal analysis data, from S2 > form S3 > form S1 > form I > form II > form III. However, the results of the dissolution rate determination were inconsistent with the heat of solution data. The stable form I shows a higher initial dissolution rate than the metastable form II and unstable form III. All modifications were converted into the stable monohydrate, form S2, during the dissolution study, suggesting that the moisture level in solid formulations should be carefully controlled.

Enhanced dissolution and bioavailability of Nateglinide by microenvironmental pH-regulated ternary solid dispersion: in-vitro and in-vivo evaluation.

PubMed

Wairkar, Sarika; Gaud, Ram; Jadhav, Namdeo

2017-09-01

Nateglinide, an Antidiabetic drug (BCS II), shows pH-dependent solubility and variable bioavailability. The purpose of study was to increase dissolution and bioavailability of Nateglinide by development of its microenvironmental pH-regulated ternary solid dispersion (MeSD). MeSD formulation of Nateglinide, poloxamer-188 and Na 2 CO 3 was prepared by melt dispersion in 1 : 2 : 0.2 w/w ratio and further characterised for solubility, In-vitro dissolution, microenvironmental pH, crystallinity/amorphism, physicochemical interactions, bioavailability in Wistar rats. Solubility of Nateglinide was increased notably in MeSD, and its in-vitro dissolution study showed fourfold increase in the dissolution, particularly in 1.2 pH buffer. Prominent reduction in the peak intensity of X-ray powder diffraction (XRPD) and absence of endotherm in DSC thermogram confirmed the amorphism of Nateglinide in MeSD. Attenuated total reflectance Fourier transform infrared spectra revealed the hydrogen bond interactions between Nateglinide and poloxamer-188. In-vivo study indicated that MeSD exhibited fourfold increase in area under curve over Nateglinide. Tmax of MeSD was observed at 0.25 h, which is beneficial for efficient management of postprandial sugar. Instead of mere transformation of the Nateglinide to its amorphous form as evidenced by DSC and XRPD, formation of a soluble carboxylate compound of Nateglinide in MeSD was predominantly responsible for dissolution and bioavailability enhancement. The study demonstrates the utility of MeSD in achieving pH-independent dissolution, reduced T max and enhanced bioavailability of Nateglinide. © 2017 Royal Pharmaceutical Society.

Preparation of finasteride capsules-loaded drug nanoparticles: formulation, optimization, in vitro, and pharmacokinetic evaluation

PubMed Central

Ahmed, Tarek A

2016-01-01

In this study, optimized freeze-dried finasteride nanoparticles (NPs) were prepared from drug nanosuspension formulation that was developed using the bottom–up technique. The effects of four formulation and processing variables that affect the particle size and solubility enhancement of the NPs were explored using the response surface optimization design. The optimized formulation was morphologically characterized using transmission electron microscopy (TEM). Physicochemical interaction among the studied components was investigated. Crystalline change was investigated using X-ray powder diffraction (XRPD). Crystal growth of the freeze-dried NPs was compared to the corresponding aqueous drug nanosuspension. Freeze-dried NPs formulation was subsequently loaded into hard gelatin capsules that were examined for in vitro dissolution and pharmacokinetic behavior. Results revealed that in most of the studied variables, some of the quadratic and interaction effects had a significant effect on the studied responses. TEM image illustrated homogeneity and shape of the prepared NPs. No interaction among components was noticed. XRPD confirmed crystalline state change in the optimized NPs. An enhancement in the dissolution rate of more than 2.5 times from capsules filled with optimum drug NPs, when compared to capsules filled with pure drug, was obtained. Crystal growth, due to Ostwald ripening phenomenon and positive Gibbs free energy, was reduced following lyophilization of the nanosuspension formulation. Pharmacokinetic parameters from drug NPs were superior to that of pure drug and drug microparticles. In conclusion, freeze-dried NPs based on drug nanosuspension formulation is a successful technique in enhancing stability, solubility, and in vitro dissolution of poorly water-soluble drugs with possible impact on the drug bioavailability. PMID:26893559

The lateritic profile of Balkouin, Burkina Faso: Geochemistry, mineralogy and genesis

NASA Astrophysics Data System (ADS)

Giorgis, Ilaria; Bonetto, Sabrina; Giustetto, Roberto; Lawane, Abdou; Pantet, Anne; Rossetti, Piergiorgio; Thomassin, Jean-Hugues; Vinai, Raffaele

2014-02-01

This study reports on the geochemical and mineralogical characterization of a lateritic profile cropping out in the Balkouin area, Central Burkina Faso, aimed at obtaining a better understanding of the processes responsible for the formation of the laterite itself and the constraints to its development. The lateritic profile rests on a Paleoproterozoic basement mostly composed of granodioritic rocks related to the Eburnean magmatic cycle passing upwards to saprolite and consists of four main composite horizons (bottom to top): kaolinite and clay-rich horizons, mottled laterite and iron-rich duricrust. In order to achieve such a goal, a multi-disciplinary analytical approach was adopted, which includes inductively coupled plasma (ICP) atomic emission and mass spectrometries (ICP-AES and ICP-MS respectively), X-ray powder diffraction (XRPD), scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and micro-Raman spectroscopy.

The influence of Ni(II) on brushite structure stabilization

NASA Astrophysics Data System (ADS)

Guerra-López, J. R.; Güida, J. A.; Ramos, M. A.; Punte, G.

2017-06-01

Brushite samples doped with Ni(II) in different concentrations, from 5% to 20%, were prepared in aqueous solution at pH = 7 and at two temperatures: 25 and 37 °C. The solid samples were characterized by chemical analysis, infrared spectroscopy (FTIR) and x-ray powder diffraction (XRPD). Chemical analysis has shown Ni(II) almost complete incorporation to the solid phase up to 15%. X-ray diffraction patterns have allowed to identify brushite phase with almost no modification of the line breadth and only small shifts of lines positions with increasing Ni(II) incorporation up to 15%. For larger Ni(II) concentration, in solution, a mixture of phases has been detected. Infrared spectra have supported diffraction results. For Ni(II) 20% and over the characteristic bands of HPO42- anions tend to vanish, and the typical shaped PO43- bands are observed. These results have allowed to establish that the presence of low levels of Ni in the synthetic process not only helps brushite formation; but, also prevents brushite from apatite conversion and, in addition, preserves brushite crystallinity. According to these findings, it is possible to propose that nickel traces present in the urinary system might be a trigger to brushite stone formation and/or growth, rather than the expected brushite conversion to hydroxyapatite. This outcome would explain the recurrent detection of difficult to treat brushite stones, observed in the last three decades.

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

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.

Advanced surface chemical analysis of continuously manufactured drug loaded composite pellets.

PubMed

Hossain, Akter; Nandi, Uttom; Fule, Ritesh; Nokhodchi, Ali; Maniruzzaman, Mohammed

2017-04-15

The aim of the present study was to develop and characterise polymeric composite pellets by means of continuous melt extrusion techniques. Powder blends of a steroid hormone (SH) as a model drug and either ethyl cellulose (EC N10 and EC P7 grades) or hydroxypropyl methylcellulose (HPMC AS grade) as polymeric carrier were extruded using a Pharma 11mm twin screw extruder in a continuous mode of operation to manufacture extruded composite pellets of 1mm length. Molecular modelling study using commercial Gaussian 09 software outlined a possible drug-polymer interaction in the molecular level to develop solid dispersions of the drug in the pellets. Solid-state analysis conducted via a differential scanning calorimetry (DSC), hot stage microscopy (HSM) and X-ray powder diffraction (XRPD) analyses revealed the amorphous state of the drug in the polymer matrices. Surface analysis using SEM/energy dispersive X-ray (EDX) of the produced pellets arguably showed a homogenous distribution of the C and O atoms in the pellet matrices. Moreover, advanced chemical surface analysis conducted via atomic force microscopy (AFM) showed a homogenous phase system having the drug molecule dispersed onto the amorphous matrices while Raman mapping confirmed the homogenous single-phase drug distribution in the manufactured composite pellets. Such composite pellets are expected to deliver multidisciplinary applications in drug delivery and medical sciences by e.g. modifying drug solubility/dissolutions or stabilizing the unstable drug (e.g. hormone, protein) in the composite network. Copyright © 2016. Published by Elsevier Inc.

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.

Ag/CuO nanoparticles prepared from a novel trinuclear compound [Cu(Imdz)4(Ag(CN)2)2] (Imdz = imidazole) by a pyrolysis display excellent antimicrobial activity

NASA Astrophysics Data System (ADS)

Adhikary, Jaydeep; Das, Balaram; Chatterjee, Sourav; Dash, Sandeep Kumar; Chattopadhyay, Sourav; Roy, Somenath; Chen, Jeng-Wei; Chattopadhyay, Tanmay

2016-06-01

One copper and two silver containing one hetero tri-nuclear precursor compound [Cu(Imdz)4(Ag(CN)2)2] (1) (Imdz = Imidazole) has been synthesized and characterized by single crystal X-ray diffraction. Simple pyrolysis of the complex at 550 °C for 4 h afforded Ag/CuO nanoparticles (NPs). The synthesized nanoparticles were characterized by ultraviolet-visible (UV-Vis), Fourier transform infrared (FT-IR), X-ray powder diffraction (XRPD), dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray photo electron spectroscopy (XPS). Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) have been employed as model microbial species to study the anti-microbial activity of the synthesized NPs. The NPs showed potent anti-microbial activity evidenced from the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values. Very high level of cell uptake and then generation of reactive oxygen species (ROS) are the origin of such strong antimicrobial activity for the NPs. However, the cytotoxicity level of the NPs towards normal human cell is very low.

2D-1D structural phase transformation of Co(II) 3,5-pyridinedicarboxylate frameworks with chromotropism.

PubMed

Cheansirisomboon, Achareeya; Pakawatchai, Chaveng; Youngme, Sujittra

2012-09-21

Two new metal-organic frameworks [Co(pydc)(H(2)O)(2)](n) (1) and [Co(pydc)(H(2)O)(4)](n)(H(2)O)(n) (2), (pydc = 3,5-pyridinedicarboxylate) have been synthesized by a diffusion method and characterized by single-crystal X-ray diffraction. The structure of 1 reveals an infinite 2D layer with honeycomb-like cavities in which each pydc ligand bridges three Co(II) ions. The adjacent 2D layers are orderly packed in an ABAB-type array via intermolecular interactions of the combined π-π stacking and hydrogen bonds to form a 3D supramolecular architecture. Interestingly, compound 1 exhibits a water induced crystal-to-amorphous transformation with chromotropism confirmed by spectroscopic techniques, elemental analysis, TGA and XRPD. When this amorphous phase (1A) was exposed to water vapor, it was readily converted into the second crystalline phase 1B with a color change. Moreover, a reversible process between 1A and 1B was performed. In the case of compound 2, pydc acts as didentate bridging ligand connecting two Co(II) ions, leading to a 1D zig-zag chain. Guest water molecules fill the gaps in between chains and form hydrogen bonds with the host chains stabilizing the 3D network of 2. Additionally, compound 2 also exhibits a water induced crystal-to-amorphous transformation with chromotropism and the reversible process was also performed between the dehydrated (2A) and rehydrated (2') forms. Surprisingly, the IR and UV-vis spectra, elemental analysis, TGA curve and XRPD pattern of the rehydrated second phase 1B are found to be identical to that of 2 and 2', these results confirm that 2, 2' and 1B are the same compound.

Determination of the post mortem interval in skeletal remains by the comparative use of different physico-chemical methods: Are they reliable as an alternative to 14C?

PubMed

Amadasi, Alberto; Cappella, Annalisa; Cattaneo, Cristina; Cofrancesco, Pacifico; Cucca, Lucia; Merli, Daniele; Milanese, Chiara; Pinto, Andrea; Profumo, Antonella; Scarpulla, Valentina; Sguazza, Emanuela

2017-05-01

The determination of the post-mortem interval (PMI) of skeletal remains is a challenging aspect in the forensic field. Previous studies focused their attention on different macroscopic and morphological aspects but a thorough and complete evaluation of the potential of chemical and physical analyses in this field of research has not been performed. In addition to luminol test and Oxford histology index (OHI) reported in a recent paper, widely spread and accessible methods based on physical aspect and chemical characteristics of skeletal remains have been investigated as potential alternatives to dating by determination of 14 C. The investigation was performed on a total of 24 archeological and forensic bone samples with known PMI, with inductively coupled plasma optical emission spectrometer (ICP-OES), inductively coupled plasma quadruple mass spectrometry (ICP-MS), Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray analysis (EDX), powder X-ray diffraction analysis (XRPD) and scanning electron microscopy (SEM). Finally, the feasibility of such alternative methods was discussed. Some results such as carbonates/phosphates ratio from FT-IR, the amounts of organic and inorganic matter by EDX, crystallite sizes with XRPD, and surface morphology obtained by SEM, showed significant trends along with PMI. Though, from a chemical point of view cut-off values and gold-standard methods still present challenges, and rather different techniques together can provide useful information toward the assessment of the PMI of skeletal remains. It is however clear that in a hypothetical flowchart those methods may be placed practically at the same level and a choice should always consider the evaluation of results by each technique, execution times and a costs/benefits relationship. Copyright © 2017 Elsevier GmbH. All rights reserved.

Structural evolution of the double perovskites Sr{sub 2}B'UO{sub 6} (B' = Mn, Fe, Co, Ni, Zn) upon reduction: Magnetic behavior of the uranium cations

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

Pinacca, R.M., E-mail: rmp@unsl.edu.ar; Viola, M.C.; Pedregosa, J.C.

2011-11-15

Highlights: {yields} Evolution of the double perovskites Sr{sub 2}B'UO{sub 6} upon reduction were studied by XRPD. {yields} Orthorhombic (Pnma) disordered perovskites SrB'{sub 0.5-x}U{sub 0.5+x}O{sub 3} were obtained at 900 {sup o}C. {yields} U{sup 5+/4+} and Zn{sup 2+} cations are distributed at random over the octahedral positions. {yields} AFM ordering for the perovskite with B' = Zn appears below 30 K. -- Abstract: We describe the preparation of five perovskite oxides obtained upon reduction of Sr{sub 2}B'UO{sub 6} (B' = Mn, Fe, Co, Ni, Zn) with H{sub 2}/N{sub 2} (5%/95%) at 900 {sup o}C during 8 h, and their structural characterizationmore » by X-ray powder diffraction (XRPD). During the reduction process there is a partial segregation of the elemental metal when B' = Co, Ni, Fe, and the corresponding B'O oxide when B' = Mn, Zn. Whereas the parent, oxygen stoichiometric double perovskites Sr{sub 2}B'UO{sub 6} are long-range ordered concerning B' and U cations. The crystal structures of the reduced phases, SrB'{sub 0.5-x}U{sub 0.5+x}O{sub 3} with 0.37 < x < 0.27, correspond to simple, disordered perovskites; they are orthorhombic, space group Pnma (No. 62), with a full cationic disorder at the B site. Magnetic measurements performed on the phase with B' = Zn, indicate uncompensated antiferromagnetic ordering of the U{sup 5+}/U{sup 4+} sublattice below 30 K.« less

Assessment of cement kiln dust (CKD) for stabilization/solidification (S/S) of arsenic contaminated soils.

PubMed

Moon, Deok Hyun; Wazne, Mahmoud; Yoon, In-Ho; Grubb, Dennis G

2008-11-30

A stabilization/solidification (S/S) process for arsenic (As) contaminated soils was evaluated using cement kiln dust (CKD). Laboratory-prepared slurries, made of either kaolinite or montmorillonite, and field soils spiked with either As(3+) or As(5+) were prepared and treated with CKD ranging from 10 to 25 wt%. Sodium arsenite and sodium arsenate at 0.1 wt% were used to simulate arsenite (As(3+)) and arsenate (As(5+)) source contamination in soils, respectively. The effectiveness of treatment was evaluated at curing periods of 1- and 7-days based on the toxicity characteristic leaching procedure (TCLP). As-CKD and As-clay-CKD slurries were also spiked at 10 wt% to evaluate As immobilization mechanism using X-ray powder diffraction (XRPD) analyses. Overall, the TCLP results showed that only the As(5+) concentrations in kaolinite amended with 25 wt% CKD after 1 day of curing were less than the TCLP regulatory limit of 5mg/L. Moreover, at 7 days of curing, all As(3+) and As(5+) concentrations obtained from kaolinite soils were less than the TCLP criteria. However, none of the CKD-amended montmorillonite samples satisfied the TCLP-As criteria at 7 days. Only field soil samples amended with 20 wt% CKD complied with the TCLP criteria within 1 day of curing, where the source contamination was As(5+). XRPD and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results showed that Ca-As-O and NaCaAsO(4).7.5H(2)O were the primary phases responsible for As(3+) and As(5+) immobilization in the soils, respectively.

A 1:1 pharmaceutical cocrystal of myricetin in combination with uncommon piracetam conformer: X-ray single crystal analysis and mechanochemical synthesis

NASA Astrophysics Data System (ADS)

Sowa, Michał; Ślepokura, Katarzyna; Matczak-Jon, Ewa

2014-01-01

Combination of two Active Pharmaceutical Ingredients, myricetin and piracetam, yields a 1:1 cocrystal characterized by X-ray single-crystal and powder diffraction, Raman spectroscopy, 1H NMR, thermal analysis (DSC and TG-DTA) methods. Constituents of the cocrystalline phase were also investigated in terms of Hirshfeld surfaces. Compounds in their neutral forms cocrystallize in the Pna21 space group of orthorhombic system. Notably, piracetam adopts an uncommon conformation, not encountered in its cocrystals previously described. In the crystal lattice, a three-dimensional hydrogen-bonded network is observed, including formation of a 2D molecular scaffolding motif. A scale-up procedure is readily available with use of solvent-drop grinding method, in which application of a variety of common solvents leads to formation of the cocrystal, as confirmed by XRPD and Raman spectroscopy.

Syntheses, structures, and properties of two new zinc(II) metal-organic frameworks based on flexible 1,6-bis(2-methyl-imidazole-1-yl)hexane ligand

NASA Astrophysics Data System (ADS)

Jin, Jun-Cheng; Fu, Ai-Yun; Li, Dian; Chang, Wen-Gui; Wu, Ju; Yang, Mei; Xie, Cheng-Gen; Xu, Guang-Nian; Cai, An-Xing; Wu, Ai-Hua

2014-11-01

Two new zinc(II) metal-organic compounds of [Zn(ADC)(bimh)]n (1) and [Zn(ADA)(bimh)]n (2) (H2ADC = 1,3-adamantanedicarboxylic acid, H2ADA = 1,3-adamantanediacetic acid, bimh = 1,6-bis(2-methyl-imidazole-1-yl)-hexane, have been structurally characterized by X-ray diffraction analysis. In compound 1, the zinc(II) ions are bridged by ADC and bimh ligands to form a 1D looped chain. In compound 2, the ADA molecules alternately bridge Zn(II) atoms to form infinite chains, and then the 1D chain is connected through the bimh ligand resulting in an undulating infinite two-dimensional (2D) polymeric network. Additionally, TG analysis, XRPD and fluorescent properties for compounds 1 and 2 are also measured and discussed.

Synthesis, structures and properties of the new lithium cobalt(II) phosphate Li{sub 4}Co(PO{sub 4}){sub 2}

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

Glaum, R., E-mail: rglaum@uni-bonn.de; Gerber, K.; Schulz-Dobrick, M.

2012-04-15

{alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} has been synthesized and crystallized by solid-state reactions. The new phosphate crystallizes in the monoclinic system (P2{sub 1}/a, Z=4, a=8.117(3) Angstrom-Sign , b=10.303(8) Angstrom-Sign , c=8.118(8) Angstrom-Sign , {beta}=104.36(8) Angstrom-Sign ) and is isotypic to {alpha}-Li{sub 4}Zn(PO{sub 4}){sub 2}. The structure of {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} has been determined from single-crystal X-ray diffraction data {l_brace}R{sub 1}=0.040, wR{sub 2}=0.135, 2278 unique reflections with F{sub o}>4{sigma}(F{sub o}){r_brace}. The crystal structure, which might be regarded as a superstructure of the wurtzite structure type, is build of layers of regular CoO{sub 4}, PO{sub 4} and Li1O{sub 4} tetrahedra. Lithium atomsmore » Li2, Li3 and Li4 are located between these layers. Thermal investigations by in-situ XRPD, DTA/TG and quenching experiments suggest decomposition followed by formation and phase transformation of Li{sub 4}Co(PO{sub 4}){sub 2}: {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} Long-Rightwards-Double-Arrow {sup 442 Degree-Sign C}{beta}-Li{sub 3}PO{sub 4}+LiCoPO{sub 4} Rightwards-Harpoon-Over-Leftwards-Harpoon {sup 773 Degree-Sign C}{beta}-Li{sub 4}Co(PO{sub 4}){sub 2} Long-Rightwards-Double-Arrow {sup quenchingto25 Degree-Sign C}{alpha}-Li{sub 4} Co(PO{sub 4}){sub 2} According to HT-XRPD at {theta}=850 Degree-Sign C{beta}-Li{sub 4}Co(PO{sub 4}){sub 2} (Pnma, Z=2, 10.3341(8) A, b=6.5829(5) A, c=5.0428(3) Angstrom-Sign ) is isostructural to {gamma}-Li{sub 3}PO{sub 4}. The powder reflectance spectrum of {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2} shows the typical absorption bands for the tetrahedral chromophore [Co{sup II}O{sub 4}]. - Graphical abstract: The complex formation and decomposition behavior of Li{sub 4}Co(PO{sub 4}){sub 2} with temperature has been elucidated. The crystal structure of its {alpha}-phase was determined from single crystal data, HT-XRPD allowed derivation of a structure model for the {beta}-phase. Both modifications belong to the Li{sub 3}PO{sub 4} structure family. Highlights: Black-Right-Pointing-Pointer Li{sub 4}Co(PO{sub 4}){sub 2} exhibits complex thermal behavior. Black-Right-Pointing-Pointer The new phosphate belongs to the Li{sub 3}PO{sub 4} structure family. Black-Right-Pointing-Pointer A single-crystal structure analysis is provided for the metastable {alpha}-Li{sub 4}Co(PO{sub 4}){sub 2}. Black-Right-Pointing-Pointer From HT-XRPD data a cation distribution model is developed for {beta}-Li{sub 4}Co(PO{sub 4}){sub 2}. Black-Right-Pointing-Pointer No electrochemical delithiation is observed up to 5 V.« less

Pharmaceutical Cocrystal of Piroxicam: Design, Formulation and Evaluation

PubMed Central

Panzade, Prabhakar; Shendarkar, Giridhar; Shaikh, Sarfaraj; Balmukund Rathi, Pavan

2017-01-01

Purpose: Cocrystallisation of drug with coformers is a promising approach to alter the solid sate properties of drug substances like solubility and dissolution. The objective of the present work was to prepare, formulate and evaluate the piroxicam cocrystal by screening various coformers. Methods: Cocrystals of piroxicam were prepared by dry grinding method. The melting point and solubility of crystalline phase was determined. The potential cocrystal was characterized by DSC, IR, XRPD. Other pharmaceutical properties like solubility and dissolution rate were also evaluated. Orodispersible tablets of piroxicam cocrystal were formulated, optimized and evaluated using 32 factorial design. Results: Cocrystals of piroxicam-sodium acetate revealed the variation in melting points and solubility. The cocrystals were obtained in 1:1 ratio with sodium acetate. The analysis of Infrared explicitly indicated the shifting of characteristic bands of piroxicam. The X-Ray Powder Diffraction pattern denoted the crystallinity of cocrystals and noteworthy difference in 2θ value of intense peaks. Differential scanning calorimetry spectra of cocrystals indicated altered endotherms corresponding to melting point. The pH solubility profile of piroxicam showed sigmoidal curve, which authenticated the pKa-dependent solubility. Piroxicam cocrystals also exhibited a similar pH-solubility profile. The cocrystals exhibited faster dissolution rate owing to cocrystallization as evident from 30% increase in the extent of dissolution. The orodispersible tablets of piroxicam cocrystals were successfully prepared by direct compression method using crosscarmelose sodium as superdisintegrant with improved disintegration time (30 sec) and dissolution rate. Conclusion: The piroxicam cocrystal with modified properties was prepared with sodium acetate and formulated as orodispersible tablets having faster disintegration and greater dissolution rate. PMID:29071222

Pharmaceutical Cocrystal of Piroxicam: Design, Formulation and Evaluation.

PubMed

Panzade, Prabhakar; Shendarkar, Giridhar; Shaikh, Sarfaraj; Balmukund Rathi, Pavan

2017-09-01

Purpose: Cocrystallisation of drug with coformers is a promising approach to alter the solid sate properties of drug substances like solubility and dissolution. The objective of the present work was to prepare, formulate and evaluate the piroxicam cocrystal by screening various coformers. Methods: Cocrystals of piroxicam were prepared by dry grinding method. The melting point and solubility of crystalline phase was determined. The potential cocrystal was characterized by DSC, IR, XRPD. Other pharmaceutical properties like solubility and dissolution rate were also evaluated. Orodispersible tablets of piroxicam cocrystal were formulated, optimized and evaluated using 3 2 factorial design. Results: Cocrystals of piroxicam-sodium acetate revealed the variation in melting points and solubility. The cocrystals were obtained in 1:1 ratio with sodium acetate. The analysis of Infrared explicitly indicated the shifting of characteristic bands of piroxicam. The X-Ray Powder Diffraction pattern denoted the crystallinity of cocrystals and noteworthy difference in 2θ value of intense peaks. Differential scanning calorimetry spectra of cocrystals indicated altered endotherms corresponding to melting point. The pH solubility profile of piroxicam showed sigmoidal curve, which authenticated the pKa-dependent solubility. Piroxicam cocrystals also exhibited a similar pH-solubility profile. The cocrystals exhibited faster dissolution rate owing to cocrystallization as evident from 30% increase in the extent of dissolution. The orodispersible tablets of piroxicam cocrystals were successfully prepared by direct compression method using crosscarmelose sodium as superdisintegrant with improved disintegration time (30 sec) and dissolution rate. Conclusion: The piroxicam cocrystal with modified properties was prepared with sodium acetate and formulated as orodispersible tablets having faster disintegration and greater dissolution rate.

Establishment of the structural and enhanced physicochemical properties of the cocrystal-2-benzyl amino pyridine with oxalic acid

NASA Astrophysics Data System (ADS)

Sangeetha, M.; Mathammal, R.

2017-09-01

We report on a cocrystal of 2-(benzyl amino) pyridine (BAP) with oxalic acid (OA) in the ratio 1:1. The cocrystal was synthesised and single crystals were grown under slow evaporation technique at room temperature. Single crystal X-ray diffraction (SCXRD) analysis determined the structure of the cocrystal formed and it belongs to orthorhombic system with Cc space group. It was also subjected to X-ray Powder diffraction (XRPD) to confirm the cocrystal structure. Hirshfeld surfaces and fingerprints were plotted to analyze the intermolecular interactions. Spectroscopic techniques such as FTIR, FT-Raman and NMR were carried out to identify the functional groups present in the cocrystal. The bioactivity of the cocrystal was revealed from the UV-Vis analysis. Computational Density Functional Theory (DFT) was adopted at the B3LYP/6-31+G** level to calculate the optimized geometrical parameters and the vibrational frequencies of the cocrystal. The non-linear optical property of the cocrystal was revealed from the SHG test. The different types of interactions and delocalization of charge were analysed from Natural Bond Orbital (NBO) calculations. The HOMO-LUMO energies and MEP surface maps confirmed the pharmaceutical importance of the (1:1) BAPOA cocrystal. The cocrystal has been explored for the invitro antioxidant activity and insilico molecular docking studies.

Local structural relaxation around Co2+ along the hardystonite-Co-åkermanite melilite solid solution

NASA Astrophysics Data System (ADS)

Ardit, Matteo; Cruciani, Giuseppe; Dondi, Michele

2012-10-01

Six pure compounds belonging to the hardystonite (Ca2ZnSi2O7)-Co-åkermanite (Ca2CoSi2O7) solid solution were investigated by the combined application of X-ray powder diffraction and electronic absorption spectroscopy. Structural refinements of the XRPD data revealed a negative excess volume of mixing due to the single isovalent substitution of Co for Zn in the tetrahedral site. In agreement with the diffraction data, deconvolution of the optical spectra showed a progressive decreasing of the crystal field strength parameter 10 Dq moving toward the Co-åkermanite end-member, meaning that the local cobalt-oxygen bond distance, < {{Co}}{-}{{O}}rangle^{{local}} , increased along the join with the amount of cobalt. The calculated structural relaxation coefficient around the fourfold coordinated Co2+ in the Ca2(Zn1- x Co x )Si2O7 join was ɛ = 0.69, very far from the one predicted by the Vegard's law ( ɛ = 0) and at variance with ɛ = 0.47 previously found for tetrahedrally coordinated Co2+ in gahnite-Co-aluminate spinel solid solution. This difference is consistent with the largest constraints existing on the spinel structure, based on cubic closest packing, compared to the more flexible layered melilite structure.

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.

Amperometric ascorbic acid sensor based on doped ferrites nanoparticles modified glassy carbon paste electrode.

PubMed

Dimitrijević, Teodora; Vulić, Predrag; Manojlović, Dragan; Nikolić, Aleksandar S; Stanković, Dalibor M

2016-07-01

In this study, a novel electrochemical sensor for quantification of ascorbic acid with amperometric detection in physiological conditions was constructed. For this purpose, cobalt and nickel ferrites were synthesized using microwave and ultrasound assistance, characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRPD), and used for modification of glassy carbon paste electrode (GCPE). It was shown that introducing these nanoparticles to the structure of GCPE led to increasing analytical performance. Co ferrite modified GCPE (CoFeGCPE) showed better characteristics toward ascorbic acid sensing. The limit of detection (LOD) obtained by sensor was calculated to be 0.0270 mg/L, with linear range from 0.1758 to 2.6010 mg/L. This sensor was successfully applied for practical analysis, and the obtained results demonstrated that the proposed procedure could be a promising replacement for the conventional electrode materials and time-consuming and expensive separation methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Spectroscopic, microchemical and petrographic analyses of plasters from ancient buildings in Lamezia Terme (Calabria, Southern Italy)

NASA Astrophysics Data System (ADS)

De Luca, Raffaella; Gigliotti, Valentina; Panarello, Mario; Bloise, Andrea; Crisci, Gino M.; Miriello, Domenico

2016-01-01

This work shows the results of the spectroscopic, microchemical and petrographic study carried out on six plasters coming from three important residential buildings of the 18th century, located in Lamezia Terme (Catanzaro, Southern Italy). To study the provenance of the raw materials used to make the plasters, one sample of limestone and two samples of sand were also collected from the quarries near Lamezia Terme and compared with the historical plasters. Samples were studied by polarized optical microscopy (OM), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. The results of these analyses allowed to determine the mineralogical, petrographical and chemical characteristics of the plasters, identify the pigments used for their coloration and provide useful information about the building techniques, the raw materials employed and the production technology of plasters during the 18th century in Lamezia Terme. SEM-EDS microanalysis also revealed the presence of gold and silver on the surface of two samples.

Mechanochemical solvent-free in situ synthesis of drug-loaded {Cu2(1,4-bdc)2(dabco)}n MOFs for controlled drug delivery

NASA Astrophysics Data System (ADS)

Nadizadeh, Zahra; Naimi-Jamal, M. Reza; Panahi, Leila

2018-03-01

In the present study, ibuprofen-loaded nano metal-organic frameworks (NMOFs) {Cu2(1,4-bdc)2(dabco)}n and {Cu2(1,4-bdc-NH2)2(dabco)}n (bdc=benzenedicarboxylic acid, and dabco=diazabicyclooctane) were synthesized by ball-milling at room temperature in 2 h. The produced drug-loaded Cu-NMOFs were studied as ibuprofen drug delivery system and exhibited well-defined drug release behavior, exceptionally high drug loading capacities and the ability to entrap the model drug. The loading efficiency for ibuprofen was determined about 50.54% and 50.27%, respectively. The drug release of NMOFs was also monitored, and all of the loaded drug was released in 1 day. The NMOFs were characterized by FT-IR spectroscopy, X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA), SEM (scanning electron microscopy), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma (ICP), UV-vis spectroscopy and N2 adsorption porosimetry (BET&BJH).

Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin.

PubMed

Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian; Rades, Thomas; Leopold, Claudia S

2015-10-27

To benefit from the optimized dissolution properties of active pharmaceutical ingredients in their amorphous forms, co-amorphisation as a viable tool to stabilize these amorphous phases is of both academic and industrial interest. Reports dealing with the physical stability and recrystallization behavior of co-amorphous systems are however limited to qualitative evaluations based on the corresponding X-ray powder diffractograms. Therefore, the objective of the study was to develop a quantification model based on X-ray powder diffractometry (XRPD), followed by a multivariate partial least squares regression approach that enables the simultaneous determination of up to four solid state fractions: crystalline naproxen, γ-indomethacin, α-indomethacin as well as co-amorphous naproxen-indomethacin. For this purpose, a calibration set that covers the whole range of possible combinations of the four components was prepared and analyzed by XRPD. In order to test the model performances, leave-one-out cross validation was performed and revealed root mean square errors of validation between 3.11% and 3.45% for the crystalline molar fractions and 5.57% for the co-amorphous molar fraction. In summary, even four solid state phases, involving one co-amorphous phase, can be quantified with this XRPD data-based approach.

Synthesis, physicochemical characterization, DFT calculation and biological activities of Fe(III) and Co(II)-omeprazole complexes. Potential application in the Helicobacter pylori eradication

NASA Astrophysics Data System (ADS)

Russo, Marcos G.; Vega Hissi, Esteban G.; Rizzi, Alberto C.; Brondino, Carlos D.; Salinas Ibañez, Ángel G.; Vega, Alba E.; Silva, Humberto J.; Mercader, Roberto; Narda, Griselda E.

2014-03-01

The reaction between the antiulcer agent omeprazole (OMZ) with Fe(III) and Co(II) ions was studied, observing a high ability to form metal complexes. The isolated microcrystalline solid complexes were characterized by elemental analysis, X-ray powder diffraction (XRPD), Scanning Electron Microscopy (SEM), magnetic measurements, thermal study, FTIR, UV-Visible, Mössbauer, electronic paramagnetic resonance (EPR), and DFT calculations. The metal-ligand ratio for both complexes was 1:2 determined by elemental and thermal analysis. FTIR spectroscopy showed that OMZ acts as a neutral bidentate ligand through the pyridinic nitrogen of the benzimidazole ring and the oxygen atom of the sulfoxide group, forming a five-membered ring chelate. Electronic, Mössbauer, and EPR spectra together with magnetic measurements indicate a distorted octahedral geometry around the metal ions, where the coordination sphere is completed by two water molecules. SEM and XRPD were used to characterize the morphology and the crystal nature of the complexes. The most favorable conformation for the Fe(III)-OMZ and Co(II)-OMZ complexes was obtained by DFT calculations by using B3LYP/6-31G(d)&LanL2DZ//B3LYP/3-21G(d)&LanL2DZ basis set. Studies of solubility along with the antibacterial activity against Helicobacter pylori for OMZ and its Co(II) and Fe(III) complexes are also reported. Free OMZ and both metal complexes showed antibacterial activity against H. pylori. Co(II)-OMZ presented a minimal inhibitory concentration ˜32 times lower than that of OMZ and ˜65 lower than Fe(III)-OMZ, revealing its promising potential use for the treatment of gastric pathologies associated with the Gram negative bacteria. The morphological changes observed in the cell membrane of the bacteria after the incubation with the metal-complexes were also analyzed by SEM microscopy. The antimicrobial activity of the complexes was proved by the viability test.

Photoassisted reduction of metal ions and organic dye by titanium dioxide nanoparticles in aqueous solution under anoxic conditions.

PubMed

Doong, Ruey-An; Hsieh, Tien-Chin; Huang, Chin-Pao

2010-07-15

The photoassisted reduction of metal ions and organic dye by metal-deposited Degussa P25 TiO(2) nanoparticles was investigated. Copper and silver ions were selected as the target metal ions to modify the surface properties of TiO(2) and to enhance the photocatalytic activity of TiO(2) towards methylene blue (MB) degradation. X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used to characterize the crystallinity, chemical species and morphology of metal-deposited TiO(2), respectively. Results showed that the particle size of metal-deposited TiO(2) was larger than that of Degussa P25 TiO(2). Based on XRPD patterns and XPS spectra, it was observed that the addition of formate promoted the photoreduction of metal ion by lowering its oxidation number, and subsequently enhancing the photodegradation efficiency and rate of MB. The pseudo-first-order rate constant (k(obs)) for MB photodegradation by Degussa P25 TiO(2) was 3.94 x 10(-2) min(-1) and increased by 1.4-1.7 times in k(obs) with metal-deposited TiO(2) for MB photodegradation compared to simple Degussa P25 TiO(2). The increase in mass loading of metal ions significantly enhanced the photodegradation efficiency of MB; the k(obs) for MB degradation increased from 3.94 x 10(-2) min(-1) in the absence of metal ion to 4.64-7.28 x 10(-2) min(-1) for Ag/TiO(2) and to 5.14-7.61 x 10(-2) min(-1) for Cu/TiO(2). In addition, the electrons generated from TiO(2) can effectively reduce metal ions and MB simultaneously under anoxic conditions. However, metal ions and organic dye would compete for electrons from the illuminated TiO(2). Copyright 2010 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

Dielectric Properties of Ca0.7Bi0.3Ti0.7Cr0.3O3 (CBTC)-CaCu3Ti4O12 (CCTO) Composite

NASA Astrophysics Data System (ADS)

Mallmann, E. J. J.; Silva, M. A. S.; Sombra, A. S. B.; Botelho, M. A.; Mazzetto, S. E.; de Menezes, A. S.; Almeida, A. F. L.; Fechine, P. B. A.

2015-01-01

The main object of this work is to study two materials with giant dielectric constants: CaCu3Ti4O12 (CCTO) and Ca0.7Bi0.3Ti0.7Cr0.3O3 (CBTC). CBTC1- x -CCTO x composites were also obtained to create a new dielectric material with dielectric properties between these two phases. Structural properties were studied by x-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and dielectric measurements. CCTO showed a cubic phase and CBTC an orthorhombic phase. An interesting result was that the dielectric constant ( K) did not follow the rule of the mixture of Lichtnecker, and this happened due to the presence of other phases of its crystalline structure, which decreases the value of K when compared to the predicted values of Lichtnecker. It was also found that the dielectric properties of the composite are very promising for use in microelectronics, according to the miniaturization factor, which is crucial for those applications.

Assessment of the Effects Exerted by Acid and Alkaline Solutions on Bone: Is Chemistry the Answer?

PubMed

Amadasi, Alberto; Camici, Arianna; Porta, Davide; Cucca, Lucia; Merli, Daniele; Milanese, Chiara; Profumo, Antonella; Rassifi, Nabila; Cattaneo, Cristina

2017-09-01

The treatment of corpses with extremely acid or basic liquids is sometimes performed in criminal contexts. A thorough characterization by chemical analysis may provide further help to macroscopic and microscopic analysis; 63 porcine bone samples were treated with solutions at different pH (1-14) for immersion periods up to 70 days, as well as in extremely acidic sulfuric acid solutions (9 M/18 M) and extremely basic sodium hydroxide. Inductively coupled optical emission spectrometry (ICP-OES)/plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) showed that only the sulfuric acid solution 18 M was able to completely dissolve the sample. In addition, chemical analysis allowed to recognize the contact between bone and substances. Hydrated calcium sulfate arose from extreme pH. The possibility of detecting the presence of human material within the residual solution was demonstrated, especially with FT-IR, ICP-OES, and EDX. © 2017 American Academy of Forensic Sciences.

The Influence of Carbonaceous Matrices and Electrocatalytic MnO₂ Nanopowders on Lithium-Air Battery Performances.

PubMed

Minguzzi, Alessandro; Longoni, Gianluca; Cappelletti, Giuseppe; Pargoletti, Eleonora; Di Bari, Chiara; Locatelli, Cristina; Marelli, Marcello; Rondinini, Sandra; Vertova, Alberto

2016-01-06

Here, we report new gas diffusion electrodes (GDEs) prepared by mixing two different pore size carbonaceous matrices and pure and silver-doped manganese dioxide nanopowders, used as electrode supports and electrocatalytic materials, respectively. MnO₂ nanoparticles are finely characterized in terms of structural (X-ray powder diffraction (XRPD), energy dispersive X-ray (EDX)), morphological (SEM, high-angle annular dark field (HAADF)-scanning transmission electron microscopy (STEM)/TEM), surface (Brunauer Emmet Teller (BET)-Barrett Joyner Halenda (BJH) method) and electrochemical properties. Two mesoporous carbons, showing diverse surface areas and pore volume distributions, have been employed. The GDE performances are evaluated by chronopotentiometric measurements to highlight the effects induced by the adopted materials. The best combination, hollow core mesoporous shell carbon (HCMSC) with 1.0% Ag-doped hydrothermal MnO₂ (M_hydro_1.0%Ag) allows reaching very high specific capacity close to 1400 mAh·g -1 . Considerably high charge retention through cycles is also observed, due to the presence of silver as a dopant for the electrocatalytic MnO₂ nanoparticles.

The Influence of Carbonaceous Matrices and Electrocatalytic MnO2 Nanopowders on Lithium-Air Battery Performances

PubMed Central

Minguzzi, Alessandro; Longoni, Gianluca; Cappelletti, Giuseppe; Pargoletti, Eleonora; Di Bari, Chiara; Locatelli, Cristina; Marelli, Marcello; Rondinini, Sandra; Vertova, Alberto

2016-01-01

Here, we report new gas diffusion electrodes (GDEs) prepared by mixing two different pore size carbonaceous matrices and pure and silver-doped manganese dioxide nanopowders, used as electrode supports and electrocatalytic materials, respectively. MnO2 nanoparticles are finely characterized in terms of structural (X-ray powder diffraction (XRPD), energy dispersive X-ray (EDX)), morphological (SEM, high-angle annular dark field (HAADF)-scanning transmission electron microscopy (STEM)/TEM), surface (Brunauer Emmet Teller (BET)-Barrett Joyner Halenda (BJH) method) and electrochemical properties. Two mesoporous carbons, showing diverse surface areas and pore volume distributions, have been employed. The GDE performances are evaluated by chronopotentiometric measurements to highlight the effects induced by the adopted materials. The best combination, hollow core mesoporous shell carbon (HCMSC) with 1.0% Ag-doped hydrothermal MnO2 (M_hydro_1.0%Ag) allows reaching very high specific capacity close to  1400 mAh·g−1. Considerably high charge retention through cycles is also observed, due to the presence of silver as a dopant for the electrocatalytic MnO2 nanoparticles. PMID:28344267

Preparation, structural characterization, and decomposition studies of two new γ-octamolybdates of 4-methylpyridine.

PubMed

Szymańska, Anna; Nitek, Wojciech; Rutkowska-Zbik, Dorota; Łasocha, Wiesław

We synthesized two new γ-octamolybdates, and determined their crystal structures from single-crystal X-ray diffraction data. Orange-yellow tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate 1 crystallizes in space group P2 1 /c with a  = 11.586(2) Å, b  = 15.526(2) Å, c  = 16.247(2) Å, β  = 118.753(1)º, Z  = 2. White tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate hydrate 2 crystallizes in space group C2/c with a  = 27.086(4) Å, b  = 11.917(2) Å, c  = 19.332(2) Å, β  = 124.427(1)º, Z  = 4. Results of crystal structure determinations are presented and discussed in this paper. Thermal stability and decomposition studies of the obtained two new γ-octamolybdates were performed using TG/DSC and XRPD methods. Both compounds decomposed with the formation of 4-methylpyridinium β-octamolybdate. The two compounds are pseudo-polymorphs, exhibiting both striking similarities as well as significant differences in their structures and properties.

Protection of hydrophobic amino acids against moisture-induced deterioration in the aerosolization performance of highly hygroscopic spray-dried powders.

PubMed

Yu, Jiaqi; Chan, Hak-Kim; Gengenbach, Thomas; Denman, John A

2017-10-01

Inhalable particles containing amorphous form of drugs or excipients may absorb atmospheric moisture, causing powder aggregation and recrystallization, adversely affecting powder dispersion and lung deposition. The present study aims to explore hydrophobic amino acids for protection against moisture in spray-dried amorphous powders, using disodium cromoglycate (DSCG) as a model drug. DSCG powders were produced by co-spray drying with isoleucine (Ile), valine (Val) and methionine (Met) in various concentrations (10, 20 and 40%w/w). Particle size distribution and morphology were measured by laser diffraction and scanning electron microscopy (SEM). Physiochemical properties of the powders were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic vapor sorption (DVS). Particle surface chemistry was analyzed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). In vitro aerosolization performance was evaluated by a next generation impactor (NGI) after the powders were stored at 60% or 75% relative humidity (RH) for one month and three months. Ile, Val and Met significantly reduced the deleterious effect of moisture on aerosol performance, depending on the amount of amino acids in the formulation. Formulations containing 10% or 20% of Ile, Val and Met showed notable deterioration in aerosol performance, with fine particle fraction (FPF) reduced by 6-15% after one-month storage at both 60% and 75% RH. However, 40% Ile was able to maintain the aerosol performance of DSCG stored at 75% RH for one month, while the FPF dropped by 7.5% after three months of storage. In contrast, 40% Val or Met were able to maintain the aerosol performance at 60% RH storage but not at 75% RH. At 40%w/w ratio, these formulations had particle surface coverage of 94.5% (molar percent) of Ile, 87.1% of Val and 84.6% of Met, respectively, which may explain their moisture protection effects. Ile, Val and Met showed promising moisture protection effect on aerosol performance. The results broaden the understanding on the use of hydrophobic amino acids as an excipient for long-term storage of inhalation powders formulations that are hygroscopic. Copyright © 2017 Elsevier B.V. All rights reserved.

New approach towards the polyol route to fabricate MFe2O4 magnetic nanoparticles: The use of MCl2 and Fe(acac)3 as chemical precursors

NASA Astrophysics Data System (ADS)

Solano, Eduardo; Yáñez, Ramón; Ricart, Susagna; Ros, Josep

2015-05-01

A new more efficient approach of the polyol route to generate MFe2O4 (M=Mn, Fe, Co, Ni, Cu, Zn) nanoparticles in triethylene glycol (TREG) is presented. The selected thermal procedure is based on the Fe metalorganic precursor (iron(III) acetylacetonate) decomposition in presence of an inorganic transition metal chloride salt (MCl2, M=Mn, Fe, Co, Ni, Cu, Zn) to produce high quality polar dispersible nanoparticles with lower production cost. In addition, the nanoparticles are stabilized by ionic (from the Cl-) and steric (TREG as capping ligand) effects inducing into the nanoparticles an extraordinary stability in different polar solvents. As result of this optimized methodology, the colloidal polar dispersible nanoparticles present a size around 10 nm with an adequate size dispersion demonstrated by analyzing transmission electron microscopy (TEM) images. X-ray powder diffraction (XRPD) results corroborate the absence of secondary phases and the high crystalline degree obtained for the spinel structure, fact proved by using synchrotron X-ray diffraction. The high magnetic performance at low and room temperature of the nanoparticles studied by magnetometry proves the high internal crystal order of the spinel. Parallel to this, the influence of the heating ramp and annealing time in the thermal procedure were also investigated for the CuFe2O4 case, where a relationship between these two parameters and the final size and their associated diameter distribution was found, allowing a possible size control of the final ferrite magnetic nanoparticles synthesized.

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.

An example of how to handle amorphous fractions in API during early pharmaceutical development: SAR114137--a successful approach.

PubMed

Petzoldt, Christine; Bley, Oliver; Byard, Stephen J; Andert, Doris; Baumgartner, Bruno; Nagel, Norbert; Tappertzhofen, Christoph; Feth, Martin Philipp

2014-04-01

The so-called pharmaceutical solid chain, which encompasses drug substance micronisation to the final tablet production, at pilot plant scale is presented as a case study for a novel, highly potent, pharmaceutical compound: SAR114137. Various solid-state analytical methods, such as solid-state Nuclear Magnetic Resonance (ssNMR), Differential Scanning Calorimetry (DSC), Dynamic Water Vapour Sorption Gravimetry (DWVSG), hot-stage Raman spectroscopy and X-ray Powder Diffraction (XRPD) were applied and evaluated to characterise and quantify amorphous content during the course of the physical treatment of crystalline active pharmaceutical ingredient (API). DSC was successfully used to monitor the changes in amorphous content during micronisation of the API, as well as during stability studies. (19)F solid-state NMR was found to be the method of choice for the detection and quantification of low levels of amorphous API, even in the final drug product (DP), since compaction during tablet manufacture was identified as a further source for the formation of amorphous API. The application of different jet milling techniques was a critical factor with respect to amorphous content formation. In the present case, the change from spiral jet milling to loop jet milling led to a decrease in amorphous API content from 20-30 w/w% to nearly 0 w/w% respectively. The use of loop jet milling also improved the processability of the API. Stability investigations on both the milled API and the DP showed a marked tendency for recrystallisation of the amorphous API content on exposure to elevated levels of relative humidity. No significant impact of amorphous API on either the chemical stability or the dissolution rate of the API in drug formulation was observed. Therefore, the presence of amorphous content in the oral formulation was of no consequence for the clinical trial phases I and II. Copyright © 2013 Elsevier B.V. All rights reserved.

The structure of denisovite, a fibrous nanocrystalline polytypic disordered ‘very complex’ silicate, studied by a synergistic multi-disciplinary approach employing methods of electron crystallography and X-ray powder diffraction

PubMed Central

Schowalter, Marco; Schmidt, Martin U.; Czank, Michael; Depmeier, Wulf; Rosenauer, Andreas

2017-01-01

Denisovite is a rare mineral occurring as aggregates of fibres typically 200–500 nm diameter. It was confirmed as a new mineral in 1984, but important facts about its chemical formula, lattice parameters, symmetry and structure have remained incompletely known since then. Recently obtained results from studies using microprobe analysis, X-ray powder diffraction (XRPD), electron crystallography, modelling and Rietveld refinement will be reported. The electron crystallography methods include transmission electron microscopy (TEM), selected-area electron diffraction (SAED), high-angle annular dark-field imaging (HAADF), high-resolution transmission electron microscopy (HRTEM), precession electron diffraction (PED) and electron diffraction tomography (EDT). A structural model of denisovite was developed from HAADF images and later completed on the basis of quasi-kinematic EDT data by ab initio structure solution using direct methods and least-squares refinement. The model was confirmed by Rietveld refinement. The lattice parameters are a = 31.024 (1), b = 19.554 (1) and c = 7.1441 (5) Å, β = 95.99 (3)°, V = 4310.1 (5) Å3 and space group P12/a1. The structure consists of three topologically distinct dreier silicate chains, viz. two xonotlite-like dreier double chains, [Si6O17]10−, and a tubular loop-branched dreier triple chain, [Si12O30]12−. The silicate chains occur between three walls of edge-sharing (Ca,Na) octahedra. The chains of silicate tetrahedra and the octahedra walls extend parallel to the z axis and form a layer parallel to (100). Water molecules and K+ cations are located at the centre of the tubular silicate chain. The latter also occupy positions close to the centres of eight-membered rings in the silicate chains. The silicate chains are geometrically constrained by neighbouring octahedra walls and present an ambiguity with respect to their z position along these walls, with displacements between neighbouring layers being either Δz = c/4 or −c/4. Such behaviour is typical for polytypic sequences and leads to disorder along [100]. In fact, the diffraction pattern does not show any sharp reflections with l odd, but continuous diffuse streaks parallel to a* instead. Only reflections with l even are sharp. The diffuse scattering is caused by (100) nano­lamellae separated by stacking faults and twin boundaries. The structure can be described according to the order–disorder (OD) theory as a stacking of layers parallel to (100). PMID:28512570

SrMoO4:Er3+-Yb3+ upconverting phosphor for photonic and forensic applications

NASA Astrophysics Data System (ADS)

Soni, Abhishek Kumar; Rai, Vineet Kumar

2016-08-01

The Er3+-Yb3+ codoped strontium molybdate (SrMoO4) phosphors have been synthesized via chemical co-precipitation method by adding ammonium hydroxide as a base reagent. The phase, crystal structure and formation of spindle-like particles present in the prepared phosphors have been recognized by using the X-ray powder diffraction (XRPD) and Field emission scanning electron microscopy (FE-SEM) techniques. The Fourier transform infrared (FTIR) spectroscopy of the developed phosphors has been analyzed to mark the different functional groups present in synthesized phosphors. The multicolour upconversion emissions observed upon excitation with 980 nm and 808 nm laser diode have been explained on the basis of dopants ions concentration, pump power dependence, energy level structure and decay curve analysis. The colour co-ordinate study confirmed that the codoped phosphor emits non-tunable green colour when excited with the 980 nm laser diode, whereas it shows the colour tunability from yellow to green region upon excitation with the 808 nm laser diode. The applicability of non-tunable green colour emission has been demonstrated in the security ink and latent finger print detection. This shows the utility of the developed phosphors in the photonic and forensic applications.

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.

Effects of Sm3+ on Luminescent Properties of LiEu(0.55-x)Y0.45 (WO4)2Smx Red Phosphor

NASA Astrophysics Data System (ADS)

Zailani, N. S.; Ghazli, M. F.; Hussin, R.; Rahim, S. Z. Abd; Mat Saad, M. N.

2018-06-01

Phosphor materials have been widely applied in lighting and displays. Rare earth elements are amongst important elements in giving luminescent properties to the phosphor. The needs to reduce rare earth element in phosphor is of interest due to cost and environmental issue. The red phosphor LiEu(0.55-x)Y0.45(WO4)2 were synthesized by substituting Sm3+ in the lattice using solid-state reaction. The effect on the substitution of Sm3+ which acts as an activator will be analysed using X-ray powder diffraction (XRPD), scanning electron microscope (SEM) and photoluminescence spectra (PL). The structure of the compound was found to be as a monoclinic which referred to the reference patterns. The optimum amount was recorded for the activator to be obtained in the host lattice for replacing the Eu3+ place as well as enhancing the intensity of the emission. The findings reveal that LiEu(0.55-x)Y0.45(MoO4)2Smx can be a more efficient red phosphor candidate used white light emitting diodes (WLEDs) applications.

Critical evaluation of sequential leaching procedures for the determination of Ni and Mn species in welding fumes.

PubMed

Berlinger, B; Náray, M; Sajó, I; Záray, G

2009-06-01

In this work, welding fume samples were collected in a welding plant, where corrosion-resistant steel and unalloyed structural steel were welded by gas metal arc welding (GMAW) and manual metal arc welding (MMAW) techniques. The welding fumes were sampled with a fixed-point sampling strategy applying Higgins-Dewell cyclones. The following solutions were used to dissolve the different species of Ni and Mn: ammonium citrate solution [1.7% (m/v) diammonium hydrogen citrate and 0.5% (m/v) citric acid monohydrate] for 'soluble' Ni, 50:1 methanol-bromine solution for metallic Ni, 0.01 M ammonium acetate for soluble Mn, 25% acetic acid for Mn(0) and Mn(2+) and 0.5% hydroxylammonium chloride in 25% acetic acid for Mn(3+) and Mn(4+). 'Insoluble' Ni and Mn contents of the samples were determined after microwave-assisted digestion with the mixture of concentrated (cc). HNO(3), cc. HCl and cc. HF. The sample solutions were analysed by inductively coupled plasma quadrupole mass spectrometry and inductively coupled plasma atomic emission spectrometry. The levels of total Ni and Mn measured in the workplace air were different because of significant differences of the fume generation rates and the distributions of the components in the welding fumes between the welding processes. For quality control of the leaching process, dissolution of the pure stoichiometric Mn and Ni compounds and their mixtures weighing was investigated using the optimized leaching conditions. The results showed the adequacy of the procedure for the pure metal compounds. Based on the extraction procedures, the predominant oxidation states of Ni and Mn proved to be very different depending on the welding techniques and type of the welded steels. The largest amount of Mn in GMAW fumes were found as insoluble Mn (46 and 35% in case of corrosion-resistant steel and unalloyed structural steel, respectively), while MMAW fumes contain mainly soluble Mn, Mn(0) and Mn(2+) (78%) and Mn(3+) and Mn(4+) (54%) in case of corrosion-resistant steel and unalloyed structural steel, respectively. According to the results of the leaching procedures, GMAW fumes are rich in oxidic Ni (79%), while Ni compounds in welding fumes generated during MMAW are mainly in easily soluble form (44%). The crystalline phases were identified in each welding fume by X-ray powder diffraction (XRPD) technique as well. From the XRPD spectra, it is clear that GMAW fumes contain predominantly magnetite (FeFe(2)O(4)). In case of structural steel welding, there was a little amount of ferrite (alpha-Fe) also found. Welding fume generated during MMAW of structural steel contained a complex alkali-alkali earth fluoride phase (KCaF(3)-CaF(2)) and some magnetite and jakobsite (MnFe(2)O(4)). The XRPD results did not fully confirm the ones obtained from the extraction experiments. However, some results, for example the rate of soluble Ni and Mn compounds compared to the total, can be useful for further investigations of welding fumes.

Low Temperature Approach to Serpentinization Processes on Ocean Worlds

NASA Astrophysics Data System (ADS)

Neto-Lima, J.; Fernández-Sampedro, M.; Prieto-Ballesteros, O.

2018-05-01

MIR results from laboratory experiments at constant temperature of 90ºC. The monitoring of the mineral alterations is done in the presence of different amounts of a Fe-Ni catalyst (awaruite) and ammonia, using XRPD, IR, SEM-EDS, XPS,RAMAN and ICP-MS.

Comparative studies of mononuclear Ni(II) and UO2(II) complexes having bifunctional coordinated groups: Synthesis, thermal analysis, X-ray diffraction, surface morphology studies and biological evaluation

NASA Astrophysics Data System (ADS)

Fahem, Abeer A.

2012-03-01

Two Schiff base ligands derived from condensation of phthalaldehyde and o-phenylenediamine in 1:2 (L1) and 2:1 (L2) having bifunctional coordinated groups (NH2 and CHO groups, respectively) and their metal complexes with Ni(II) and UO2(II) have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibilities and spectral data (IR, 1H NMR, mass and solid reflectance) as well as thermal, XRPD and SEM analysis. The formula [Ni(L1)Cl2]·2.5H2O, [UO2(L1)(NO3)2]·2H2O, [Ni(L2)Cl2]·1.5H2O and [UO2(L2)(NO3)2] have been suggested for the complexes. The vibrational spectral data show that the ligands behave as neutral ligands and coordinated to the metal ions in a tetradentate manner. The Ni(II) complexes are six coordinate with octahedral geometry and the ligand field parameters: Dq, B, β and LFSE were calculated while, UO2(II) complexes are eight coordinate with dodecahedral geometry and the force constant, FUsbnd O and bond length, RUsbnd O were calculated. The thermal decomposition of complexes ended with metal chloride/nitrate as a final product and the highest thermal stability is displayed by [UO2(L2)(NO3)2] complex. The X-ray powder diffraction data revealed the formation of nano sized crystalline complexes. The SEM analysis provides the morphology of the synthesized compounds and SEM image of [UO2(L2)(NO3)2] complex exhibits nano rod structure. The growth-inhibiting potential of the ligands and their complexes has been assessed against a variety of bacterial and fungal strains.

Super-resolution differential interference contrast microscopy by structured illumination.

PubMed

Chen, Jianling; Xu, Yan; Lv, Xiaohua; Lai, Xiaomin; Zeng, Shaoqun

2013-01-14

We propose a structured illumination differential interference contrast (SI-DIC) microscopy, breaking the diffraction resolution limit of differential interference contrast (DIC) microscopy. SI-DIC extends the bandwidth of coherent transfer function of the DIC imaging system, thus the resolution is improved. With 0.8 numerical aperture condenser and objective, the reconstructed SI-DIC image of 53 nm polystyrene beads reveals lateral resolution of approximately 190 nm, doubling that of the conventional DIC image. We also demonstrate biological observations of label-free cells with improved spatial resolution. The SI-DIC microscopy can provide sub-diffraction resolution and high contrast images with marker-free specimens, and has the potential for achieving sub-diffraction resolution quantitative phase imaging.

Mesoporous Titania Powders: The Role of Precursors, Ligand Addition and Calcination Rate on Their Morphology, Crystalline Structure and Photocatalytic Activity

PubMed Central

Masolo, Elisabetta; Meloni, Manuela; Garroni, Sebastiano; Mulas, Gabriele; Enzo, Stefano; Baró, Maria Dolors; Rossinyol, Emma; Rzeszutek, Agnieszka; Herrmann-Geppert, Iris; Pilo, Maria

2014-01-01

We evaluate the influence of the use of different titania precursors, calcination rate, and ligand addition on the morphology, texture and phase content of synthesized mesoporous titania samples, parameters which, in turn, can play a key role in titania photocatalytic performances. The powders, obtained through the evaporation-induced self-assembly method, are characterized by means of ex situ X-Ray Powder Diffraction (XRPD) measurements, N2 physisorption isotherms and transmission electron microscopy. The precursors are selected basing on two different approaches: the acid-base pair, using TiCl4 and Ti(OBu)4, and a more classic route with Ti(OiPr)4 and HCl. For both precursors, different specimens were prepared by resorting to different calcination rates and with and without the addition of acetylacetone, that creates coordinated species with lower hydrolysis rates, and with different calcination rates. Each sample was employed as photoanode and tested in the water splitting reaction by recording I-V curves and comparing the results with commercial P25 powders. The complex data framework suggests that a narrow pore size distribution, due to the use of acetylacetone, plays a major role in the photoactivity, leading to a current density value higher than that of P25. PMID:28344237

Emplacement of pyroclastic density currents (PDCs) in a deep-sea environment: The Val d'Aveto Formation case (Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Di Capua, Andrea; Groppelli, Gianluca

2016-12-01

The occurrence of PDC deposits in a foredeep basin sequence, named Val d'Aveto Formation (32-29 Ma, Northern Apennines, Italy), provides new information on the behavior of pyroclastic density currents entering the water. In this work, stratigraphic, petrographic and mineralogical features that characterize three pyroclastic deposits have been described and analyzed in the field (facies and lithological analysis on the blocky-size fraction) and in the laboratory (image analyses on the blocky-size detritus, optical analyses of the microtextures, mineralogical analyses through X-ray powder diffraction (XRPD) and scanning electron microscope with energy dispersive X-ray spectometry (SEM-EDS). The deposits are lapilli- to blocky-size, with a blocky-size fraction constituted of accidental detritus. In thin sections, their groundmass texture varies from porphyritic to eutaxitic where coarser particles become close each others. Growth rims have been also detected around plagioclase crystals. Pyrite habits and oxidation, and plagioclase albitization are consistent with hydrothermal temperature conditions of 200 °C. All these results have been compared with the information provided by modern examples of PDC deposits and laboratory experiments on the behavior of water/hot particles mixing. Grain-to-grain collision has been considered as the main flow mechanism that sustained and avoided the disaggregation of the PDCs entering the water.

Synthesis, crystal structure, and protonation behaviour in solution of the recently-discovered drug metabolite, N1,N10-diacetyltriethylenetetramine

NASA Astrophysics Data System (ADS)

Wichmann, Kathrin A.; Söhnel, Tilo; Cooper, Garth J. S.

2012-03-01

N1,N10-diacetyltriethylenetetramine (DAT) is a recently-discovered major in vivo metabolite of triethylenetetramine (TETA), a highly-selective CuII chelator currently under clinical development as a novel first-in-class therapeutic for the cardiovascular, renal and retinal complications of diabetes mellitus. Characterisation of DAT is an integral aspect of the pharmacological work-up required to support this clinical development programme and, to our knowledge, no previous synthesis for it has been published. Here we report the synthesis of DAT dihydrochloride (DAT·2 HCl); its crystal structure as determined by X-ray single-crystal (XRD) and powder diffraction (XRPD); and protonation constants and species distribution in aqueous solution, which represents the different protonation states of DAT at different pH values. The crystal structure of DAT·2 HCl reveals 3D-assemblies of alternating 2D-layers comprising di-protonated DAT strands and anionic species, which form an extensive hydrogen-bond network between amine groups, acetyl groups, and chloride anions. Potentiometric titrations show that HDAT+ is the physiologically relevant state of DAT in solution. These findings contribute to the understanding of TETA's pharmacology and to its development for the experimental therapeutics of the diabetic complications.

Physico-chemical and Biological Evaluation of Flavonols: Fisetin, Quercetin and Kaempferol Alone and Incorporated in beta Cyclodextrins.

PubMed

Corina, Danciu; Bojin, Florina; Ambrus, Rita; Muntean, Delia; Soica, Codruta; Paunescu, Virgil; Cristea, Mirabela; Pinzaru, Iulia; Dehelean, Cristina

2017-01-01

Fisetin,quercetin and kaempferol are among the important representatives of flavonols, biological active phytocomounds, with low water solubility. To evaluate the antimicrobial effect, respectively the antiproliferative and pro apoptotic activity on the B164A5 murine melanoma cell line of pure flavonols and their beta cyclodextrins complexes. Incorporation of fisetin, quercetin and kaempferol in beta cyclodextrins was proved by scanning electron microscopy (SEM), differencial scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). Pure compounds and their complexes were tested for antiproliferative (MTT) and pro-apoptotic activity (Annexin V-PI) on the B164A5 murine melanoma cell line and for the antimicrobial properties (Disk Diffusion Method) on the selected strains. The phytocompounds presented in a different manner in vitro chemopreventive activity against B164A5 murine melanoma cell line and weak antimicrobial effect. The three flavonols: fisetin, quercetin and kaempferol were successfully incorporated in beta-cyclodextrin (BCD) and hydroxylpropyl-beta-cyclodextrin (HPBCD). Incorporation in beta cyclodextrins had a mix effect on the biological activity conducing to decrease, increase or consistent effect compared to pure phytocompound, depending on the screened process and on the chosen combination. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A microhydrodynamic rationale for selection of bead size in preparation of drug nanosuspensions via wet stirred media milling.

PubMed

Li, Meng; Alvarez, Paulina; Bilgili, Ecevit

2017-05-30

Although wet stirred media milling has proven to be a robust process for producing nanoparticle suspensions of poorly water-soluble drugs and thereby enhancing their bioavailability, selection of bead size has been largely empirical, lacking fundamental rationale. This study aims to establish such rationale by investigating the impact of bead size at various stirrer speeds on the drug breakage kinetics via a microhydrodynamic model. To this end, stable suspensions of griseofulvin, a model BCS Class II drug, were prepared using hydroxypropyl cellulose and sodium dodecyl sulfate. The suspensions were milled at four different stirrer speeds (1000-4000rpm) using various sizes (50-1500μm) of zirconia beads. Laser diffraction, SEM, and XRPD were used for characterization. Our results suggest that there is an optimal bead size that achieves fastest breakage at each stirrer speed and that it shifts to a smaller size at higher speed. Calculated microhydrodynamic parameters reveal two counteracting effects of bead size: more bead-bead collisions with less energy/force upon a decrease in bead size. The optimal bead size exhibits a negative power-law correlation with either specific energy consumption or the microhydrodynamic parameters. Overall, this study rationalizes the use of smaller beads for more energetic wet media milling. Copyright © 2017 Elsevier B.V. All rights reserved.

Amorphization of itraconazole by inorganic pharmaceutical excipients: comparison of excipients and processing methods.

PubMed

Grobelny, Pawel; Kazakevich, Irina; Zhang, Dan; Bogner, Robin

2015-01-01

The aim of this study was to investigate the effects of solid carriers and processing routes on the properties of amorphous solid dispersions of itraconazole. Three solid carriers with a range of surface properties were studied, (1) a mesoporous silicate, magnesium aluminum silicate (Neusilin US2), (2) a nonporous silicate of corresponding composition (Veegum) and (3) a non-silicate, inorganic excipient, calcium phosphate dibasic anhydrous (A-TAB). The drug was incorporated via either solvent-deposition or ball milling. Both the maximum drug deposited by solvent-based method that produced an amorphous composite and the time for complete amorphization by co-milling was determined by X-ray powder diffraction (XRPD). Changes in the drug and excipients were monitored by nitrogen adsorption and wettability of the powder. The ability of the excipients to amorphize the drug and enhance its dissolution was related to the powder characteristics. Neusilin provided the fastest amorphization time in the mill and highest drug loading by solvent-deposition, compared with the other two excipients. Solvent-deposition provided greater dissolution enhancement than milling, due to the reduction in Neusilin porosity during high energy milling.This study confirms that substrates as well as the processing routes have notable influence on the drug deposition, amorphization, physical stability and drug in vitro release.

Two New Sandwich-Type Polyoxomolybdates Functionalized with Diphosphonates: Efficient and Selective Oxidation of Sulfides to Sulfones

PubMed Central

Sun, Xiaopeng; Hu, Feng; Wan, Rong; Singh, Vikram; Ma, Pengtao; Wang, Jingping

2017-01-01

Two sandwich-type polyoxomolybdates Na8[MO2{Mo2O5(O3PCH3C(O)PO3)}2] (M = Ni2+ (1); Co2+ (2)) were synthesized by one-pot reaction of Na2HPMo12O40·14H2O, 1-hydroxy ethidene diphosphonic acid (HEDP=HOC(CH3)(PO3H2)2), and (1) NiCl2/CoCl2 (2). Compounds 1 and 2 were characterized by single crystal X-ray analysis, X-ray powder diffraction (XRPD), IR spectroscopy, 31P NMR spectra, UV-vis spectroscopy, and thermogravimetric analyses (TGA). Structural analysis reveals that 1 and 2 exhibit similar centrosymmetric structure, which consists of one transition metal (TM) ion sandwiched by two same subunits {Mo2O5(O3PCH3C(O)PO3)}. The clusters 1 and 2 show efficient catalytic activities for oxidation of thioanisole. Moreover, they are catalytically selective for oxidizing thioanisole. Both resuable polyoxomolybdates 1 and 2 catalysts show good thermo- and hydrolytic stability. It is noted that compound 1 shows outstanding catalytic activity for oxidation of various sulfides to corresponding sulfones with 93–100% selectivity at 97–100% conversion in one hour under mild conditions, which is potentially valuable to the removal of organic sulfides. PMID:29027947

Thermal, spectroscopic and laser properties of Nd3+ in gadolinium scandium gallium garnet crystal produced by optical floating zone method

NASA Astrophysics Data System (ADS)

Tian, Li; Wang, Shuxian; Wu, Kui; Wang, Baolin; Yu, Haohai; Zhang, Huaijin; Cai, Huaqiang; Huang, Hui

2013-12-01

A neodymium-doped gadolinium scandium gallium garnet (Nd:GSGG) single crystal with dimensions of Φ 5 × 20 mm2 has been grown by means of optical floating zone (OFZ). X-ray powder diffraction (XRPD) result shows that the as-grown Nd:GSGG crystal possesses a cubic structure with space group Ia3d and a cell parameter of a = 1.2561 nm. Effective elemental segregation coefficients of the Nd:GSGG as-grown crystal were calculated by using X-ray fluorescence (XRF). The thermal properties of the Nd:GSGG crystal were systematically studied by measuring the specific heat, thermal expansion and thermal diffusion coefficient, and the thermal conductivity of this crystal was calculated. The absorption and luminescence spectra of Nd:GSGG were measured at room temperature (RT). By using the Judd-Ofelt (J-O) theory, the theoretical radiative lifetime was calculated and compared with the experimental result. Continuous wave (CW) laser performance was achieved with the Nd:GSGG at the wavelength of 1062 nm when it was pumped by a laser diode (LD). A maximum output power of 0.792 W at 1062 nm was obtained with a slope efficiency of 11.89% under a pump power of 7.36 W, and an optical-optical conversion efficiency of 11.72%.

3D printing of tablets containing multiple drugs with defined release profiles.

PubMed

Khaled, Shaban A; Burley, Jonathan C; Alexander, Morgan R; Yang, Jing; Roberts, Clive J

2015-10-30

We have employed three-dimensional (3D) extrusion-based printing as a medicine manufacturing technique for the production of multi-active tablets with well-defined and separate controlled release profiles for three different drugs. This 'polypill' made by a 3D additive manufacture technique demonstrates that complex medication regimes can be combined in a single tablet and that it is viable to formulate and 'dial up' this single tablet for the particular needs of an individual. The tablets used to illustrate this concept incorporate an osmotic pump with the drug captopril and sustained release compartments with the drugs nifedipine and glipizide. This combination of medicines could potentially be used to treat diabetics suffering from hypertension. The room temperature extrusion process used to print the formulations used excipients commonly employed in the pharmaceutical industry. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray powder diffraction (XRPD) were used to assess drug-excipient interaction. The printed formulations were evaluated for drug release using USP dissolution testing. We found that the captopril portion showed the intended zero order drug release of an osmotic pump and noted that the nifedipine and glipizide portions showed either first order release or Korsmeyer-Peppas release kinetics dependent upon the active/excipient ratio used. Copyright © 2015. Published by Elsevier B.V.

A minitablet formulation made from electrospun nanofibers.

PubMed

Poller, Bettina; Strachan, Clare; Broadbent, Roland; Walker, Greg F

2017-05-01

The purpose of this study was to evaluate electrospun drug loaded nanofibers as a new matrix for minitablets. Prednisone, a poorly water-soluble drug, was loaded into povidone (polyvinylpyrrolidone, PVP) nanofibers using the process of electrospinning. The drug-loaded nanofiber mat was compressed into minitablets with a 2mm diameter and a height of 2.63±0.04mm. SEM analysis of the minitablet identified a nano-web structure with a nanofiber diameter in the range of 400-500nm. The minitablets met the requirements of the US Pharmacopeia with respect to content uniformity and friability. DSC and XRPD analysis of the minitablet indicated that the drug-polymer mixture was a one-phase amorphous system. XRPD analysis of the drug loaded nanofiber mat after 10-months of storage at ambient temperature showed no evidence of recrystallization of the drug. Solubility and dissolution properties of the drug formulated into a nanofiber mat and minitablet were evaluated. These results show that electrospun nanofibers may provide a useful matrix for the further development of minitablets. Copyright © 2017 Elsevier B.V. All rights reserved.

Implementation of a process analytical technology system in a freeze-drying process using Raman spectroscopy for in-line process monitoring.

PubMed

De Beer, T R M; Allesø, M; Goethals, F; Coppens, A; Heyden, Y Vander; De Diego, H Lopez; Rantanen, J; Verpoort, F; Vervaet, C; Remon, J P; Baeyens, W R G

2007-11-01

The aim of the present study was to propose a strategy for the implementation of a Process Analytical Technology system in freeze-drying processes. Mannitol solutions, some of them supplied with NaCl, were used as models to freeze-dry. Noninvasive and in-line Raman measurements were continuously performed during lyophilization of the solutions to monitor real time the mannitol solid state, the end points of the different process steps (freezing, primary drying, secondary drying), and physical phenomena occurring during the process. At-line near-infrared (NIR) and X-ray powder diffractometry (XRPD) measurements were done to confirm the Raman conclusions and to find out additional information. The collected spectra during the processes were analyzed using principal component analysis and multivariate curve resolution. A two-level full factorial design was used to study the significant influence of process (freezing rate) and formulation variables (concentration of mannitol, concentration of NaCl, volume of freeze-dried sample) upon freeze-drying. Raman spectroscopy was able to monitor (i) the mannitol solid state (amorphous, alpha, beta, delta, and hemihydrate), (ii) several process step end points (end of mannitol crystallization during freezing, primary drying), and (iii) physical phenomena occurring during freeze-drying (onset of ice nucleation, onset of mannitol crystallization during the freezing step, onset of ice sublimation). NIR proved to be a more sensitive tool to monitor sublimation than Raman spectroscopy, while XRPD helped to unravel the mannitol hemihydrate in the samples. The experimental design results showed that several process and formulation variables significantly influence different aspects of lyophilization and that both are interrelated. Raman spectroscopy (in-line) and NIR spectroscopy and XRPD (at-line) not only allowed the real-time monitoring of mannitol freeze-drying processes but also helped (in combination with experimental design) us to understand the process.

Diffractive Optical Analysis for Refractive Index Sensing using Transparent Phase Gratings

PubMed Central

Kumawat, Nityanand; Pal, Parama; Varma, Manoj

2015-01-01

We report the implementation of a micro-patterned, glass-based photonic sensing element that is capable of label-free biosensing. The diffractive optical analyzer is based on the differential response of diffracted orders to bulk as well as surface refractive index changes. The differential read-out suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6 × 10−7 was achieved with this technique with scope for further improvement. PMID:26578408

Preparation and in vitro evaluation of hydrophilic fenretinide nanoparticles.

PubMed

Ledet, Grace A; Graves, Richard A; Glotser, Elena Y; Mandal, Tarun K; Bostanian, Levon A

2015-02-20

Fenretinide is an effective anti-cancer drug with high in vitro cytotoxicity and low in vivo systemic toxicity. In clinical trials, fenretinide has shown poor therapeutic efficacy following oral administration - attributed to its low bioavailability and solubility. The long term goal of this project is to develop a formulation for the oral delivery of fenretinide. The purpose of this part of the study was to prepare and characterize hydrophilic nanoparticle formulations of fenretinide. Three different ratios of polyvinyl pyrrolidone (PVP) to fenretinide were used, namely, 3:1, 4:1, and 5:1. Both drug and polymer were dissolved in a mixture of methanol and dichloromethane (2:23 v/v). Rotary evaporation was used to remove the solvents, and, following reconstitution with water, a high pressure homogenizer was used to form nanoparticles. The particle size and polydispersity index were measured before and after lyophilization. The formulations were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD). The effectiveness of the formulations was assessed by release studies and Caco-2 cell permeability assays. As the PVP content increased, the recovered particle size following lyophilization became more consistent with the pre-lyophilization particle size, especially for those formulations with less lactose. The DSC scans of the formulations did not show any fenretinide melting endotherms, indicating that the drug was either present in an amorphous form in the formulation or that a solid solution of the drug in PVP had formed. For the release studies, the highest drug release among the formulations was 249.2±35.5ng/mL for the formulation with 4:1 polymer-to-drug. When the permeability of the formulations was evaluated in a Caco-2 cell model, the mean normalized flux for each treatment group was significantly higher (p<0.05) from the fenretinide control. The formulation containing 4:1 polymer-to-drug ratio and 6:5 lactose-to-formulation ratio emerged as the optimal choice for further evaluation as a potential oral delivery formulation for fenretinide. Copyright © 2014 Elsevier B.V. All rights reserved.

Exact solution for four-order acousto-optic Bragg diffraction with arbitrary initial conditions.

PubMed

Pieper, Ron; Koslover, Deborah; Poon, Ting-Chung

2009-03-01

An exact solution to the four-order acousto-optic (AO) Bragg diffraction problem with arbitrary initial conditions compatible with exact Bragg angle incident light is developed. The solution, obtained by solving a 4th-order differential equation, is formalized into a transition matrix operator predicting diffracted light orders at the exit of the AO cell in terms of the same diffracted light orders at the entrance. It is shown that the transition matrix is unitary and that this unitary matrix condition is sufficient to guarantee energy conservation. A comparison of analytical solutions with numerical predictions validates the formalism. Although not directly related to the approach used to obtain the solution, it was discovered that all four generated eigenvalues from the four-order AO differential matrix operator are expressed simply in terms of Euclid's Divine Proportion.

High-throughput and in situ EDXRD investigation on the formation of two new metal aminoethylphosphonates - Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}) and Ca(OH)(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3}){center_dot}2H{sub 2}O

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

Schmidt, Corinna; Feyand, Mark; Rothkirch, Andre

2012-04-15

The system Ca{sup 2+}/2-aminoethylphosphonic acid/H{sub 2}O/NaOH was systematically investigated using high-throughput methods. The experiments led to one new compound Ca(O{sub 3}PC{sub 2} H{sub 4}NH{sub 2}) (1) and the crystal structure was determined using in house X-ray powder diffraction data (monoclinic, P2{sub 1}/c, a=9.7753(3), b=6.4931(2), c=8.4473(2) A, {beta}=106.46(2) Degree-Sign , V=514.20(2) A{sup 3}, Z=4). The formation of 1 was investigated by in situ energy dispersive X-ray diffraction measurements (EDXRD) at beamline F3 at HASYLAB (light source DORIS III), DESY, Hamburg. An intermediate, Ca(OH)(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3}){center_dot}2H{sub 2}O (2), was observed and could be isolated from the reaction mixture at ambientmore » temperatures by quenching the reaction. The crystal structure of 2 was determined from XRPD data using synchrotron radiation (monoclinic, P2{sub 1}/m, a=11.2193(7), b=7.1488(3), c=5.0635(2) A, {beta}=100.13(4) Degree-Sign , V=399.78(3) A{sup 3}, Z=2). - Graphical abstarct: The detailed in situ energy dispersive X-ray diffraction (EDXRD) investigation on the formation of the new inorganic-organic hybrid compound Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}) leads to the discovery of a new crystalline intermediate phase. Both crystal structures were elucidated using X-ray powder diffraction data. Highlights: Black-Right-Pointing-Pointer High-throughput investigation led to new metal aminoethylphosphonate Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}). Black-Right-Pointing-Pointer The formation of Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 2}) was followed by in situ EDXRD measurements. Black-Right-Pointing-Pointer The crystalline intermediate Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3})(OH){center_dot}2H{sub 2}O was discovered. Black-Right-Pointing-Pointer Isolation of Ca(O{sub 3}PC{sub 2}H{sub 4}NH{sub 3})(OH){center_dot}2H{sub 2}O was accomplished by quenching experiments. Black-Right-Pointing-Pointer The structures were determined using X-ray powder diffraction data.« less

Co-grinding Effect on Crystalline Zaltoprofen with β-cyclodextrin/Cucurbit[7]uril in Tablet Formulation

PubMed Central

Li, Shanshan; Lin, Xiang; Xu, Kailin; He, Jiawei; Yang, Hongqin; Li, Hui

2017-01-01

This work aimed to investigate the co-grinding effects of β-cyclodextrin (β-CD) and cucurbit[7]uril (CB[7]) on crystalline zaltoprofen (ZPF) in tablet formulation. Crystalline ZPF was prepared through anti-solvent recrystallization and fully analyzed through single-crystal X-ray diffraction. Co-ground dispersions and mono-ground ZPF were prepared using a ball grinding process. Results revealed that mono-ground ZPF slightly affected the solid state, solubility, and dissolution of crystalline ZPF. Co-ground dispersions exhibited completely amorphous states and elicited a significant reinforcing effect on drug solubility. UV-vis spectroscopy, XRPD, FT-IR, DSC, ssNMR, and molecular docking demonstrated the interactions in the amorphous product. Hardness tests on blank tablets with different β-CD and CB[7] contents suggested the addition of β-CD or CB[7] could enhance the compressibility of the powder mixture. Disintegration tests showed that CB[7] could efficiently shorten the disintegrating time. Dissolution tests indicated that β-CD and CB[7] could accelerate the drug dissolution rate via different mechanisms. Specifically, CB[7] could accelerate the dissolution rate by improving disintegration and β-CD showed a distinct advantage in solubility enhancement. Based on the comparative study on β-CD and CB[7] for tablet formulation combined with co-grinding, we found that CB[7] could be considered a promising drug delivery, which acted as a disintegrant. PMID:28368030

Co-grinding Effect on Crystalline Zaltoprofen with β-cyclodextrin/Cucurbit[7]uril in Tablet Formulation.

PubMed

Li, Shanshan; Lin, Xiang; Xu, Kailin; He, Jiawei; Yang, Hongqin; Li, Hui

2017-04-03

This work aimed to investigate the co-grinding effects of β-cyclodextrin (β-CD) and cucurbit[7]uril (CB[7]) on crystalline zaltoprofen (ZPF) in tablet formulation. Crystalline ZPF was prepared through anti-solvent recrystallization and fully analyzed through single-crystal X-ray diffraction. Co-ground dispersions and mono-ground ZPF were prepared using a ball grinding process. Results revealed that mono-ground ZPF slightly affected the solid state, solubility, and dissolution of crystalline ZPF. Co-ground dispersions exhibited completely amorphous states and elicited a significant reinforcing effect on drug solubility. UV-vis spectroscopy, XRPD, FT-IR, DSC, ssNMR, and molecular docking demonstrated the interactions in the amorphous product. Hardness tests on blank tablets with different β-CD and CB[7] contents suggested the addition of β-CD or CB[7] could enhance the compressibility of the powder mixture. Disintegration tests showed that CB[7] could efficiently shorten the disintegrating time. Dissolution tests indicated that β-CD and CB[7] could accelerate the drug dissolution rate via different mechanisms. Specifically, CB[7] could accelerate the dissolution rate by improving disintegration and β-CD showed a distinct advantage in solubility enhancement. Based on the comparative study on β-CD and CB[7] for tablet formulation combined with co-grinding, we found that CB[7] could be considered a promising drug delivery, which acted as a disintegrant.

Syntheses, structures and luminescent properties of a series of 3D lanthanide coordination polymers with tripodal semirigid ligand

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

Qin Junsheng; Department of Applied Chemistry, Jilin Institute of Chemical Technology, Jilin 132022; Du Dongying

2011-02-15

Reactions of the tripodal bridging ligand 5-(4-carboxy-phenoxy)-isophthalic acid (abbreviated as H{sub 3}cpia) with lanthanide salts lead to the formation of a family of different coordination polymers, that is, [Ln(cpia)(H{sub 2}O){sub 2}]{sub n}.nH{sub 2}O (Ln=Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Dy (7), Er (8), Tm (9) and Y (10)) in the presence of formic acid or diethylamine, which are characterized by elemental analysis, IR spectrum, thermogravimetric analysis (TGA), XRPD spectrum and single-crystal X-ray diffraction. Compounds 1-10 are isostructural and exhibit three-dimensional microporous frameworks. Furthermore, the photoluminescent properties of 4, 5 and 7 have been studiedmore » in detail. -- Graphical abstract: Reactions of the tripodal bridging ligand (H{sub 3}cpia) with lanthanide ions lead to the formation of a series of coordination polymers in the presence of formic acid or diethylamine. Display Omitted Research Highlights: {yields} Ten new lanthanides-based coordination polymers (1-10) have been synthesized. {yields} 1-10 exhibit 3D (4,8)-connected fluorite topology networks with 1D channel parallel to the b-axis. {yields} Compounds 4, 5 and 7 exhibit characteristic luminescence of Sm{sup 3+}, Eu{sup 3+} and Dy{sup 3+} ions, respectively.« less

Co-grinding Effect on Crystalline Zaltoprofen with β-cyclodextrin/Cucurbit[7]uril in Tablet Formulation

NASA Astrophysics Data System (ADS)

Li, Shanshan; Lin, Xiang; Xu, Kailin; He, Jiawei; Yang, Hongqin; Li, Hui

2017-04-01

This work aimed to investigate the co-grinding effects of β-cyclodextrin (β-CD) and cucurbit[7]uril (CB[7]) on crystalline zaltoprofen (ZPF) in tablet formulation. Crystalline ZPF was prepared through anti-solvent recrystallization and fully analyzed through single-crystal X-ray diffraction. Co-ground dispersions and mono-ground ZPF were prepared using a ball grinding process. Results revealed that mono-ground ZPF slightly affected the solid state, solubility, and dissolution of crystalline ZPF. Co-ground dispersions exhibited completely amorphous states and elicited a significant reinforcing effect on drug solubility. UV-vis spectroscopy, XRPD, FT-IR, DSC, ssNMR, and molecular docking demonstrated the interactions in the amorphous product. Hardness tests on blank tablets with different β-CD and CB[7] contents suggested the addition of β-CD or CB[7] could enhance the compressibility of the powder mixture. Disintegration tests showed that CB[7] could efficiently shorten the disintegrating time. Dissolution tests indicated that β-CD and CB[7] could accelerate the drug dissolution rate via different mechanisms. Specifically, CB[7] could accelerate the dissolution rate by improving disintegration and β-CD showed a distinct advantage in solubility enhancement. Based on the comparative study on β-CD and CB[7] for tablet formulation combined with co-grinding, we found that CB[7] could be considered a promising drug delivery, which acted as a disintegrant.

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

Viani, Alberto, E-mail: viani@itam.cas.cz; Sotiriadis, Konstantinos; Len, Adél

Full characterization of fired-clay bricks is crucial for the improvement of process variables in manufacturing and, in case of old bricks, for restoration/replacement purposes. To this aim, five bricks produced in a plant in Czech Republic in the past have been investigated with a combination of analytical techniques in order to derive information on the firing process. An additional old brick from another brickyard was also used to study the influence of different raw materials on sample microstructure. The potential of X-ray diffraction with the Rietveld method and small angle neutron scattering technique has been exploited to describe the phasemore » transformations taking place during firing and characterize the brick microstructure. Unit-cell parameter of spinel and amount of hematite are proposed as indicators of the maximum firing temperature, although for the latter, limited to bricks produced from the same raw material. The fractal quality of the surface area of pores obtained from small angle neutron scattering is also suggested as a method to distinguish between bricks produced from different raw clays. - Highlights: • Rietveld method helps in describing microstructure and physical properties of bricks. • XRPD derived cell parameter of spinel is proposed as an indicator of firing temperature. • SANS effectively describes brick micro and nanostructure, including closed porosity. • Fractal quality of pore surface is proposed as ‘fingerprint’ of brick manufacturing.« less

The effect of amino acid excipients on morphology and solid-state properties of multi-component spray-dried formulations for pulmonary delivery of biomacromolecules.

PubMed

Sou, Tomás; Kaminskas, Lisa M; Nguyen, Tri-Hung; Carlberg, Renée; McIntosh, Michelle P; Morton, David A V

2013-02-01

For a dry powder carrier platform to be suitable for pulmonary delivery of potent biomacromolecules, it has to be aerosolisable and capable of stabilising the biomacromolecules. In the present study, strategies aiming to produce a multi-component spray-dried powder formulation with a stable amorphous glassy matrix containing mannitol, trehalose, glycine and alanine, while using leucine as a particle formation and aerosolisation enhancing agent were investigated. The results from in vitro aerosolisation studies demonstrated high fine particle fractions (FPFs) from several formulations. Scanning electronic micrographs (SEMs) revealed distinct morphological features of these formulations in response to increasing leucine concentration: from the apparent insufficiency for discrete particle formation, to reduced particle agglomeration, to increased surface corrugation. X-ray powder diffraction (XRPD) results indicated that partially ordered leucine resulting from self-assembly on the particle surface is important for the amino acid to function effectively as an encapsulating agent. This may also play a role in inhibiting crystallisation of other components within the formulation. In conclusion, the results suggest that with suitable particle size, good dispersibility and solid-state properties, selected trehalose/leucine combinations appear to have good potential for development into a universal carrier platform for pulmonary delivery of potent biomacromolecules and the work highlights areas deserving further investigation. Copyright © 2012 Elsevier B.V. All rights reserved.

Multi-component sorption of Pb(II), Cu(II) and Zn(II) onto low-cost mineral adsorbent.

PubMed

Prasad, Murari; Xu, Huan-yan; Saxena, Sona

2008-06-15

Multi-component sorption studies were carried out for attenuation of divalent heavy metal cations (Pb2+, Cu2+ and Zn2+) by a low-cost mineral adsorbent from the aqueous solution. Kinetic and equilibrium batch-type sorption experiments were conducted under variable conditions for multi-component using low-grade (<12%P2O5) phosphate rock. Percentage of multiple heavy metal species removal increases with decreasing initial metals concentration and particle size. The equilibrium data were well described to a lesser extent by Freundlich model but Langmuir model seemed to be more appropriate with the fixation capacity obtained at room temperature for Pb2+, Cu2+ and Zn2+ was 227.2, 769.2 and 666.6 micromol g(-1), respectively. Two simple kinetic models were tested to investigate the adsorption mechanism. Rate constants have been found nearly constant at all metal concentrations for first order. The comparison of adsorption capacity of low-grade phosphate rock decreases in multi-component system as compared to single component due to ionic interactions. X-ray powder diffraction (XRPD) technique was used to ascertain the formation of new metal phases followed by surface complexation. Used adsorbents have been converted into a value added product by utilizing innovative Zero-waste concept to solve the used adsorbents disposal problem and thus protecting the environment.

Ultrasonic green synthesis of an Ag/CP nanocomposite for enhanced photodegradation effectiveness.

PubMed

Chang, Hai Ning; Hou, Suo Xia; Hao, Zeng Chuan; Cui, Guang Hua

2018-01-01

A nanoparticle of cobalt(II) coordination polymer (CP), [Co(L)(npht)] n (1) (H 2 npht=4-nitrophthalic acid, L=1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene) and its nanocomposite (Ag/CP 1) were obtained by the sonochemical approach and characterized by IR, elemental analysis, thermogravimetric analyses (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRPD). CP 1 shows a 1D double chain containing two different helical chains, which is further extended into a two-dimensional supramolecular framework by C-H⋯O hydrogen bonding interactions. The photoluminescence properties and photocatalytic properties of the nanoparticles of CP 1 and Ag/CP 1 on the degradation of methylene blue (MB) were investigated, Ag/CP 1 exhibited excellent photocatalytic activity under UV and visible light, which can be attributed to the strong interactions between Ag nanorods and CP 1, which lead to electron-hole pair separation between Ag nanorods and CP 1. In addition, the photocatalytic mechanism is also carried out by introducing t-butyl alcohol (TBA) as a widely used ·OH scavenger. The influence of ultrasound irradiation time and power on the morphology and size of the nanostructure CP 1 were studied. The results indicated that a decrease in time and an increase in power led to a decrease of particle size. Copyright © 2017 Elsevier B.V. All rights reserved.

Syntheses, crystal structures, and water adsorption behaviors of jungle-gym-type porous coordination polymers containing nitro moieties

NASA Astrophysics Data System (ADS)

Uemura, Kazuhiro; Onishi, Fumiaki; Yamasaki, Yukari; Kita, Hidetoshi

2009-10-01

NO 2 containing dicarboxylate bridging ligands, nitroterephthalate (bdc-NO 2) and 2,5-dinitroterephthalate (bdc-(NO 2) 2), afford porous coordination polymers, {[Zn 2(bdc-NO 2) 2(dabco)]· solvents} n ( 2⊃ solvents) and {[Zn 2(bdc-(NO 2) 2) 2(dabco)]· solvents} n ( 3⊃ solvents). Both compounds form jungle-gym-type regularities, where a 2D square grid composed of dinuclear Zn 2 units and dicarboxylate ligands is bridged by dabco molecules to extend the 2D layers into a 3D structure. In 2⊃ solvents and 3⊃ solvents, a rectangle pore surrounded by eight Zn 2 corners contains two and four NO 2 moieties, respectively. Thermal gravimetry (TG) and X-ray powder diffraction (XRPD) measurements reveal that both compounds maintain the frameworks regularities without guest molecules and with solvents such as MeOH, EtOH, i-PrOH, and Me 2CO. Adsorption measurements reveal that dried 2 and 3 adsorb H 2O molecules to be {[Zn 2(bdc-NO 2) 2(dabco)]·4H 2O} n ( 2⊃4H 2O) and {[Zn 2(bdc-(NO 2) 2) 2(dabco)]·6H 2O} n ( 3⊃6H 2O), showing the pore hydrophilicity enhancement caused by NO 2 group introduction.

Nuclear surface diffuseness revealed in nucleon-nucleus diffraction

NASA Astrophysics Data System (ADS)

Hatakeyama, S.; Horiuchi, W.; Kohama, A.

2018-05-01

The nuclear surface provides useful information on nuclear radius, nuclear structure, as well as properties of nuclear matter. We discuss the relationship between the nuclear surface diffuseness and elastic scattering differential cross section at the first diffraction peak of high-energy nucleon-nucleus scattering as an efficient tool in order to extract the nuclear surface information from limited experimental data involving short-lived unstable nuclei. The high-energy reaction is described by a reliable microscopic reaction theory, the Glauber model. Extending the idea of the black sphere model, we find one-to-one correspondence between the nuclear bulk structure information and proton-nucleus elastic scattering diffraction peak. This implies that we can extract both the nuclear radius and diffuseness simultaneously, using the position of the first diffraction peak and its magnitude of the elastic scattering differential cross section. We confirm the reliability of this approach by using realistic density distributions obtained by a mean-field model.

Radiation damage and annealing in plutonium tetrafluoride

NASA Astrophysics Data System (ADS)

McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; Sweet, Lucas; McNamara, Bruce; Delegard, Calvin; Jevremovic, Tatjana

2017-12-01

A sample of plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an unusual color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, thermogravimetric/differential thermal analysis and X-ray diffraction evaluations were conducted to determine the plutonium's crystal structure, oxide content, and moisture content; these analyses reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial thermogravimetric/differential thermal analyses, it was discovered that an exothermic event occurred within the material near 414 °C. X-ray diffraction analyses were conducted on the annealed tetrafluoride. The X-ray diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414 °C event. The following commentary describes the series of thermogravimetric/differential thermal and X-ray diffraction analyses that were conducted as part of this investigation at PNNL.

Investigating the Effects of Low Temperature Annealing of Amorphous Corrosion Resistant Alloys.

DTIC Science & Technology

1980-11-01

Ray Diffraction.................................................... 6 Differential Scanning Calorimetry....................................... 9...17 LIST OF FIGURES Figure 1. X- Ray Diffraction Results From Fe32Ni 36Cr 4P 2 B Annealed for One Hour at...Various Temperatures (Cr Ka Radiation) ................................. 7 Figure 2. X- Ray Diffraction Results From FeU2NiaeCr14SieB Annealed for One

Zirconium phosphate nanoplatelets: a biocompatible nanomaterial for drug delivery to cancer

NASA Astrophysics Data System (ADS)

Saxena, Vipin; Diaz, Agustin; Clearfield, Abraham; Batteas, James D.; Hussain, Muhammad Delwar

2013-02-01

The objective of this study was to evaluate the biocompatibility of zirconium phosphate (ZrP) nanoplatelets (NPs), and their use in drug delivery. ZrP and doxorubicin-intercalated ZrP (DOX:ZrP) NPs were characterized by using X-Ray Powder Diffraction (XRPD), Thermogravimetric Analysis (TGA), Transmission Electron Micrography (TEM), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Biocompatibility of ZrP NPs was evaluated in human embryonic kidney (HEK-293), breast cancer (MCF-7), metastatic breast cancer (MDA-MB-231), ovarian cancer (OVCAR-3), resistant cancer (NCI-RES/ADR) cells and mouse macrophage (RAW 264.7) cell lines. Hemocompatibility of ZrP NPs was evaluated with human red blood cells. Simulated body fluid (SBF) of pH 7.4 was used to determine the in vitro release of doxorubicin from DOX:ZrP NPs. Cellular uptake and in vitro cytotoxicity studies of DOX:ZrP NPs were determined in MDA-MB-231. The ZrP nanomaterial can be prepared in the 100-200 nm size range with a platelet-like shape. The ZrP NPs themselves are biocompatible, hemocompatible and showed no toxicity to the macrophage cells. ZrP NPs can intercalate high loads (35% w/w) of doxorubicin between their layers. The release of DOX was sustained for about 2 weeks. DOX:ZrP NPs showed higher cellular uptake and increased cytotoxicity than free DOX in MDA-MB-231 cells. ZrP NPs are highly biocompatible, can intercalate large amounts of drugs and sustain the release of drugs. ZrP NPs improved the cellular uptake and cytotoxicity of DOX to MDA-MB-231 cells. ZrP NPs are promising nanocarriers for drug delivery in cancer therapy.The objective of this study was to evaluate the biocompatibility of zirconium phosphate (ZrP) nanoplatelets (NPs), and their use in drug delivery. ZrP and doxorubicin-intercalated ZrP (DOX:ZrP) NPs were characterized by using X-Ray Powder Diffraction (XRPD), Thermogravimetric Analysis (TGA), Transmission Electron Micrography (TEM), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Biocompatibility of ZrP NPs was evaluated in human embryonic kidney (HEK-293), breast cancer (MCF-7), metastatic breast cancer (MDA-MB-231), ovarian cancer (OVCAR-3), resistant cancer (NCI-RES/ADR) cells and mouse macrophage (RAW 264.7) cell lines. Hemocompatibility of ZrP NPs was evaluated with human red blood cells. Simulated body fluid (SBF) of pH 7.4 was used to determine the in vitro release of doxorubicin from DOX:ZrP NPs. Cellular uptake and in vitro cytotoxicity studies of DOX:ZrP NPs were determined in MDA-MB-231. The ZrP nanomaterial can be prepared in the 100-200 nm size range with a platelet-like shape. The ZrP NPs themselves are biocompatible, hemocompatible and showed no toxicity to the macrophage cells. ZrP NPs can intercalate high loads (35% w/w) of doxorubicin between their layers. The release of DOX was sustained for about 2 weeks. DOX:ZrP NPs showed higher cellular uptake and increased cytotoxicity than free DOX in MDA-MB-231 cells. ZrP NPs are highly biocompatible, can intercalate large amounts of drugs and sustain the release of drugs. ZrP NPs improved the cellular uptake and cytotoxicity of DOX to MDA-MB-231 cells. ZrP NPs are promising nanocarriers for drug delivery in cancer therapy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34242e

Diffractive shear interferometry for extreme ultraviolet high-resolution lensless imaging

NASA Astrophysics Data System (ADS)

Jansen, G. S. M.; de Beurs, A.; Liu, X.; Eikema, K. S. E.; Witte, S.

2018-05-01

We demonstrate a novel imaging approach and associated reconstruction algorithm for far-field coherent diffractive imaging, based on the measurement of a pair of laterally sheared diffraction patterns. The differential phase profile retrieved from such a measurement leads to improved reconstruction accuracy, increased robustness against noise, and faster convergence compared to traditional coherent diffractive imaging methods. We measure laterally sheared diffraction patterns using Fourier-transform spectroscopy with two phase-locked pulse pairs from a high harmonic source. Using this approach, we demonstrate spectrally resolved imaging at extreme ultraviolet wavelengths between 28 and 35 nm.

Radiation damage and annealing in plutonium tetrafluoride

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

McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey

Plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an off-normal color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, Thermogravimetric/Differential Thermal Analysis and X-ray Diffraction evaluations were conducted to determine the plutonium’s crystal structure, oxide content, and moisture content; these analyses reported that themore » plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. During the initial Thermogravimetric/Differential Thermal analyses, it was discovered that an exothermic event occurred within the material near 414°C. X-ray Diffraction analyses were conducted on the annealed tetrafluoride. The X-ray Diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414°C event. The following commentary describes the series of Thermogravimetric/Differential Thermal and X-ray Diffraction analyses that were conducted as part of this investigation at PNNL, in collaboration with the University of Utah Nuclear Engineering Program.« less

Radiation damage and annealing in plutonium tetrafluoride

DOE PAGES

McCoy, Kaylyn; Casella, Amanda; Sinkov, Sergey; ...

2017-08-03

A sample of plutonium tetrafluoride that was separated prior to 1966 at the Hanford Site in Washington State was analyzed at the Pacific Northwest National Laboratory (PNNL) in 2015 and 2016. The plutonium tetrafluoride, as received, was an unusual color and considering the age of the plutonium, there were questions about the condition of the material. These questions had to be answered in order to determine the suitability of the material for future use or long-term storage. Therefore, thermogravimetric/differential thermal analysis and X-ray diffraction evaluations were conducted to determine the plutonium's crystal structure, oxide content, and moisture content; these analysesmore » reported that the plutonium was predominately amorphous and tetrafluoride, with an oxide content near ten percent. Freshly fluorinated plutonium tetrafluoride is known to be monoclinic. And during the initial thermogravimetric/differential thermal analyses, it was discovered that an exothermic event occurred within the material near 414 °C. X-ray diffraction analyses were conducted on the annealed tetrafluoride. The X-ray diffraction analyses indicated that some degree of recrystallization occurred in conjunction with the 414 °C event. This commentary describes the series of thermogravimetric/differential thermal and X-ray diffraction analyses that were conducted as part of this investigation at PNNL.« less

A scheme for lensless X-ray microscopy combining coherent diffraction imaging and differential corner holography.

PubMed

Capotondi, F; Pedersoli, E; Kiskinova, M; Martin, A V; Barthelmess, M; Chapman, H N

2012-10-22

We successfully use the corners of a common silicon nitride supporting window in lensless X-ray microscopy as extended references in differential holography to obtain a real space hologram of the illuminated object. Moreover, we combine this method with the iterative phasing techniques of coherent diffraction imaging to enhance the spatial resolution on the reconstructed object, and overcome the problem of missing areas in the collected data due to the presence of a beam stop, achieving a resolution close to 85 nm.

Raman mapping of mannitol/lysozyme particles produced via spray drying and single droplet drying.

PubMed

Pajander, Jari Pekka; Matero, Sanni; Sloth, Jakob; Wan, Feng; Rantanen, Jukka; Yang, Mingshi

2015-06-01

This study aimed to investigate the effect of a model protein on the solid state of a commonly used bulk agent in spray-dried formulations. A series of lysozyme/mannitol formulations were spray-dried using a lab-scale spray dryer. Further, the surface temperature of drying droplet/particles was monitored using the DRYING KINETICS ANALYZER™ (DKA) with controllable drying conditions mimicking the spray-drying process to estimate the drying kinetics of the lysozyme/mannitol formulations. The mannitol polymorphism and the spatial distribution of lysozyme in the particles were examined using X-ray powder diffractometry (XRPD) and Raman microscopy. Partial Least Squares Discriminant Analysis was used for analyzing the Raman microscopy data. XRPD results indicated that a mixture of β-mannitol and α-mannitol was produced in the spray-drying process which was supported by the Raman analysis, whereas Raman analysis indicated that a mixture of α-mannitol and δ-mannitol was detected in the single particles from DKA. In addition Raman mapping indicated that the presence of lysozyme seemed to favor the appearance of α-mannitol in the particles from DKA evidenced by close proximity of lysozyme and mannitol in the particles. It suggested that the presence of lysozyme tend to induce metastable solid state forms upon the drying process.

Light Diffraction by Large Amplitude Ultrasonic Waves in Liquids

NASA Technical Reports Server (NTRS)

Adler, Laszlo; Cantrell, John H.; Yost, William T.

2016-01-01

Light diffraction from ultrasound, which can be used to investigate nonlinear acoustic phenomena in liquids, is reported for wave amplitudes larger than that typically reported in the literature. Large amplitude waves result in waveform distortion due to the nonlinearity of the medium that generates harmonics and produces asymmetries in the light diffraction pattern. For standing waves with amplitudes above a threshold value, subharmonics are generated in addition to the harmonics and produce additional diffraction orders of the incident light. With increasing drive amplitude above the threshold a cascade of period-doubling subharmonics are generated, terminating in a region characterized by a random, incoherent (chaotic) diffraction pattern. To explain the experimental results a toy model is introduced, which is derived from traveling wave solutions of the nonlinear wave equation corresponding to the fundamental and second harmonic standing waves. The toy model reduces the nonlinear partial differential equation to a mathematically more tractable nonlinear ordinary differential equation. The model predicts the experimentally observed cascade of period-doubling subharmonics terminating in chaos that occurs with increasing drive amplitudes above the threshold value. The calculated threshold amplitude is consistent with the value estimated from the experimental data.

New water soluble heterometallic complex showing unpredicted coordination modes of EDTA

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

Mudsainiyan, R.K., E-mail: mudsainiyanrk@gmail.com; Jassal, A.K.; Chawla, S.K., E-mail: sukhvinder.k.chawla@gmail.com

2015-10-15

A mesoporous 3D polymeric complex (I) having formula ([Zr(IV)O-μ{sup 3}-(EDTA)Fe(III)OH]·H{sub 2}O){sub n} has been crystallized and characterized by various techniques. Single-crystal X-ray diffraction analysis revealed that complex (I) crystallized in chiral monoclinic space group Cc (space group no. 9) with unexpected coordination modes of EDTA and mixture of two transition metal ions. In this complex, the coordination number of Zr(IV) ion is seven where four carboxylate oxygen atoms, two nitrogen atoms, one oxide atom are coordinating with Zr(IV). Fe(III) is four coordinated and its coordination environment is composed of three different carboxylic oxygen atoms from three different EDTA and onemore » oxygen atom of –OH group. The structure consists of 4-c and 16-c (2-nodal) net with new topology and point symbol for net is (3{sup 36}·4{sup 54}·5{sup 30})·(3{sup 6}). TGA study and XRPD pattern showed that the coordination polymer is quite stable even after losing water molecule and –OH ion. Quenching behavior in fluorescence of ligand is observed by complexation with transition metal ions is due to n–π⁎ transition. The SEM micrograph shows the morphology of complex (I) exhibits spherical shape with size ranging from 50 to 280 nm. The minimum N{sub 2} (S{sub BET}=8.7693 m{sup 2}/g) and a maximum amount of H{sub 2} (high surface area=1044.86 m{sup 2}/g (STP)) could be adsorbed at 77 K. From DLS study, zeta potential is calculated i.e. −7.94 shows the negative charges on the surface of complex. Hirshfeld surface analysis and fingerprint plots revealed influence of weak or non bonding interactions in crystal packing of complex. - Graphical abstract: The complex (I) crystallized with unexpected coordination modes of EDTA having 4-c, 16-c net with new topology and point symbol is (3{sup 36}·4{sup 54}·5{sup 30})·(3{sup 6}). TGA study and XRPD pattern proved its stability with high preference of H{sub 2} uptake by complex. - Highlights: • 3D complex having unexpected coordination modes of EDTA with Zr(IV) and Fe(III). • The structure consists of 4-c and 16-c (2-nodal) net with new topology. • Reasonable S{sub BET} (8.7693 m{sup 2}/g) but high H{sub 2} uptake (1044.86 m{sup 2}/g) due to limited pore size. • Quenching behavior due to n–π⁎ transition by complexation with transition metal ions. • From DLS study, zeta potential value is −7.94.« less

Formation of curcumin nanoparticles via solution-enhanced dispersion by supercritical CO2

PubMed Central

Zhao, Zheng; Xie, Maobin; Li, Yi; Chen, Aizheng; Li, Gang; Zhang, Jing; Hu, Huawen; Wang, Xinyu; Li, Shipu

2015-01-01

In order to enhance the bioavailability of poorly water-soluble curcumin, solution-enhanced dispersion by supercritical carbon dioxide (CO2) (SEDS) was employed to prepare curcumin nanoparticles for the first time. A 24 full factorial experiment was designed to determine optimal processing parameters and their influence on the size of the curcumin nanoparticles. Particle size was demonstrated to increase with increased temperature or flow rate of the solution, or with decreased precipitation pressure, under processing conditions with different parameters considered. The single effect of the concentration of the solution on particle size was not significant. Curcumin nanoparticles with a spherical shape and the smallest mean particle size of 325 nm were obtained when the following optimal processing conditions were adopted: P =20 MPa, T =35°C, flow rate of solution =0.5 mL·min−1, concentration of solution =0.5%. Fourier transform infrared (FTIR) spectroscopy measurement revealed that the chemical composition of curcumin basically remained unchanged. Nevertheless, X-ray powder diffraction (XRPD) and thermal analysis indicated that the crystalline state of the original curcumin decreased after the SEDS process. The solubility and dissolution rate of the curcumin nanoparticles were found to be higher than that of the original curcumin powder (approximately 1.4 μg/mL vs 0.2 μg/mL in 180 minutes). This study revealed that supercritical CO2 technologies had a great potential in fabricating nanoparticles and improving the bioavailability of poorly water-soluble drugs. PMID:25995627

Formation of curcumin nanoparticles via solution-enhanced dispersion by supercritical CO2.

PubMed

Zhao, Zheng; Xie, Maobin; Li, Yi; Chen, Aizheng; Li, Gang; Zhang, Jing; Hu, Huawen; Wang, Xinyu; Li, Shipu

2015-01-01

In order to enhance the bioavailability of poorly water-soluble curcumin, solution-enhanced dispersion by supercritical carbon dioxide (CO2) (SEDS) was employed to prepare curcumin nanoparticles for the first time. A 2(4) full factorial experiment was designed to determine optimal processing parameters and their influence on the size of the curcumin nanoparticles. Particle size was demonstrated to increase with increased temperature or flow rate of the solution, or with decreased precipitation pressure, under processing conditions with different parameters considered. The single effect of the concentration of the solution on particle size was not significant. Curcumin nanoparticles with a spherical shape and the smallest mean particle size of 325 nm were obtained when the following optimal processing conditions were adopted: P = 20 MPa, T = 35°C, flow rate of solution = 0.5 mL·min(-1), concentration of solution = 0.5%. Fourier transform infrared (FTIR) spectroscopy measurement revealed that the chemical composition of curcumin basically remained unchanged. Nevertheless, X-ray powder diffraction (XRPD) and thermal analysis indicated that the crystalline state of the original curcumin decreased after the SEDS process. The solubility and dissolution rate of the curcumin nanoparticles were found to be higher than that of the original curcumin powder (approximately 1.4 μg/mL vs 0.2 μg/mL in 180 minutes). This study revealed that supercritical CO2 technologies had a great potential in fabricating nanoparticles and improving the bioavailability of poorly water-soluble drugs.

Synthesis and piezoelectric properties of (1 - x)Bi0.5(Na0.8K0.2)0.5TiO3-xSr2ZrTiO6 ceramics

NASA Astrophysics Data System (ADS)

Onishi, Ryo; Ogawa, Hirotaka; Iida, Daiki; Kan, Akinori

2017-10-01

The effects of Sr2ZrTiO6 (SZT) addition on the piezoelectric properties of (1 - x)Bi0.5(Na0.8K0.2)0.5TiO3 (BNKT)-xSZT ceramics were characterized in this study. The X-ray powder diffraction (XRPD) profiles and Raman spectra of the ceramics in the composition range of 0-0.02 implies the presence of morphotropic phase boundary (MPB) which consists of the rhombohedral and tetragonal phases. Moreover, the temperature dependence of dielectric loss indicated a presence of the ferroelectric-relaxor transition temperature (T F-R) of around 75 °C for x = 0.005 and the temperature dependence shifted to a lower temperature at x = 0.01. The temperature dependence of the P-E hysteresis loop of the ceramics at the compositions of x = 0.005-0.02 showed pinched hysteresis loops above T F-R. Regarding the piezoelectric constant (d 33), it was increased by SZT addition in the MPB region (x = 0-0.01) and the highest d 33 of 202 pC/N was obtained at the composition of x = 0.0025. The S-E unipolar loop was also evaluated, the strain of the ceramic increased up to x = 0.02; and the highest d33* = 436 pm/V was obtained at the composition of x = 0.02.

Search for life on Mars: Evaluation of techniques

NASA Technical Reports Server (NTRS)

Schwartz, D. E.; Mancinelli, R. L.; White, M. R.

1995-01-01

An important question for exobiology is, did life evolve on Mars? To answer this question, experiments must be conducted on the martian surface. Given current mission constraints on mass, power, and volume, these experiments can only be performed using proposed analytical techniques such as: electron microscopy, X-ray fluorescence, X-ray diffraction, a-proton backscatter, g-ray spectrometry, differential thermal analysis, differential scanning calorimetry, pyrolysis gas chromatography, mass spectrometry, and specific element detectors. Using prepared test samples consisting of 1% organic matter (bovine serum albumin) in palagonite and a mixture of palagonite, clays, iron oxides, and evaporites, it was determined that a combination of X-ray diffraction and differential thermal analysis coupled with gas chromatography provides the best insight into the chemistry, mineralogy, and geological history of the samples.

Search for life on Mars: evaluation of techniques.

PubMed

Schwartz, D E; Mancinelli, R L; White, M R

1995-03-01

An important question for exobiology is, did life evolve on Mars? To answer this question, experiments must be conducted on the martian surface. Given current mission constraints on mass, power, and volume, these experiments can only be performed using proposed analytical techniques such as: electron microscopy, X-ray fluorescence, X-ray diffraction, alpha-proton backscatter, gamma-ray spectrometry, differential thermal analysis, differential scanning calorimetry, pyrolysis gas chromatography, mass spectrometry, and specific element detectors. Using prepared test samples consisting of 1% organic matter (bovine serum albumin) in palagonite and a mixture of palagonite, clays, iron oxides, and evaporites, it was determined that a combination of X-ray diffraction and differential thermal analysis coupled with gas chromatography provides the best insight into the chemistry, mineralogy, and geological history of the samples.

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.

Red soil as a regenerable sorbent for high temperature removal of hydrogen sulfide from coal gas.

PubMed

Ko, Tzu-Hsing; Chu, Hsin; Lin, Hsiao-Ping; Peng, Ching-Yu

2006-08-25

In this study, hydrogen sulfide (H(2)S) was removed from coal gas by red soil under high temperature in a fixed-bed reactor. Red soil powders were collected from the northern, center and southern of Taiwan. They were characterized by XRPD, porosity analysis and DCB chemical analysis. Results show that the greater sulfur content of LP red soils is attributed to the higher free iron oxides and suitable sulfidation temperature is around 773K. High temperature has a negative effect for use red soil as a desulfurization sorbent due to thermodynamic limitation in a reduction atmosphere. During 10 cycles of regeneration, after the first cycle the red soil remained stable with a breakthrough time between 31 and 36 min. Hydrogen adversely affects sulfidation reaction, whereas CO exhibits a positive effect due to a water-shift reaction. COS was formed during the sulfidation stage and this was attributed to the reaction of H(2)S and CO. Results of XRPD indicated that, hematite is the dominant active species in fresh red soil and iron sulfide (FeS) is a product of the reaction between hematite and hydrogen sulfide in red soils. The spinel phase FeAl(2)O(4) was found during regeneration, moreover, the amount of free iron oxides decreased after regeneration indicating the some of the free iron oxide formed a spinel phase, further reducting the overall desulfurization efficiency.

Diffracting aperture based differential phase contrast for scanning X-ray microscopy.

PubMed

Kaulich, Burkhard; Polack, Francois; Neuhaeusler, Ulrich; Susini, Jean; di Fabrizio, Enzo; Wilhein, Thomas

2002-10-07

It is demonstrated that in a zone plate based scanning X-ray microscope, used to image low absorbing, heterogeneous matter at a mesoscopic scale, differential phase contrast (DPC) can be implemented without adding any additional optical component to the normal scheme of the microscope. The DPC mode is simply generated by an appropriate positioning and alignment of microscope apertures. Diffraction from the apertures produces a wave front with a non-uniform intensity. The signal recorded by a pinhole photo diode located in the intensity gradient is highly sensitive to phase changes introduced by the specimen to be recorded. The feasibility of this novel DPC technique was proven with the scanning X-ray microscope at the ID21 beamline of the European Synchrotron Radiation facility (ESRF) operated at 6 keV photon energy. We observe a differential phase contrast, similar to Nomarski's differential interference contrast for the light microscope, which results in a tremendous increase in image contrast of up to 20 % when imaging low absorbing specimen.

High-throughput 96-well solvent mediated sonic blending synthesis and on-plate solid/solution stability characterization of pharmaceutical cocrystals.

PubMed

Luu, Van; Jona, Janan; Stanton, Mary K; Peterson, Matthew L; Morrison, Henry G; Nagapudi, Karthik; Tan, Helming

2013-01-30

A 96-well high-throughput cocrystal screening workflow has been developed consisting of solvent-mediated sonic blending synthesis and on-plate solid/solution stability characterization by XRPD. A strategy of cocrystallization screening in selected blend solvents including water mixtures is proposed to not only manipulate solubility of the cocrystal components but also differentiate physical stability of the cocrystal products. Caffeine-oxalic acid and theophylline-oxalic acid cocrystals were prepared and evaluated in relation to saturation levels of the cocrystal components and stability of the cocrystal products in anhydrous and hydrous solvents. AMG 517 was screened with a number of coformers, and solid/solution stability of the resulting cocrystals on the 96-well plate was investigated. A stability trend was observed and confirmed that cocrystals comprised of lower aqueous solubility coformers tended to be more stable in water. Furthermore, cocrystals which could be isolated under hydrous solvent blending condition exhibited superior physical stability to those which could only be obtained under anhydrous condition. This integrated HTS workflow provides an efficient route in an API-sparing approach to screen and identify cocrystal candidates with proper solubility and solid/solution stability properties. Copyright © 2012 Elsevier B.V. All rights reserved.

Mechanical design of a precision linear flexural stage for 3D x-ray diffraction microscope at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Shu, D.; Liu, W.; Kearney, S.; Anton, J.; Tischler, J. Z.

2015-09-01

The 3-D X-ray diffraction microscope is a new nondestructive tool for the three-dimensional characterization of mesoscopic materials structure. A flexural-pivot-based precision linear stage has been designed to perform a wire scan as a differential aperture for the 3-D diffraction microscope at the Advanced Photon Source, Argonne National Laboratory. The mechanical design and finite element analyses of the flexural stage, as well as its initial mechanical test results with laser interferometer are described in this paper.

Simple fiber-optic confocal microscopy with nanoscale depth resolution beyond the diffraction barrier.

PubMed

Ilev, Ilko; Waynant, Ronald; Gannot, Israel; Gandjbakhche, Amir

2007-09-01

A novel fiber-optic confocal approach for ultrahigh depth-resolution (

Use of natural clays as sorbent materials for rare earth ions: Materials characterization and set up of the operative parameters.

PubMed

Iannicelli-Zubiani, Elena Maria; Cristiani, Cinzia; Dotelli, Giovanni; Gallo Stampino, Paola; Pelosato, Renato; Mesto, Ernesto; Schingaro, Emanuela; Lacalamita, Maria

2015-12-01

Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH. The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption-desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk. The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analyses. The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture ≈ 50%, release ≈ 70%) is obtained when the uptake and release processes are performed at pH=5 and pH=1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coordination-organometallic hybrid materials based on the trinuclear M(II)-Ru(II) (M=Ni and Zn) complexes: Synthesis, structural characterization, luminescence and electrochemical properties

NASA Astrophysics Data System (ADS)

Pawal, S. B.; Lolage, S. R.; Chavan, S. S.

2018-02-01

A new series of trinuclear complexes of the type Ni[R-C6H4Ndbnd CH(O)C6H3Ctbnd CRu(dppe)2Cl]2 (1a-c) and Zn[Rsbnd C6H4Ndbnd CH(O)C6H3Ctbnd CRu(dppe)2Cl]2 (2a-c) have been prepared from the reaction of trans-[RuCl(dppe)2Ctbnd Csbnd C6H3(OH)(CHO)] (1) with aniline, 4-nitroaniline and 4-methoxyaniline (R1-3) in presence of nickel acetate and zinc acetate in CH2Cl2/MeOH (1:1) mixture. The structural properties of the complexes have been characterized by elemental analyses and spectroscopic techniques viz. FTIR, UV-Visible, 1H NMR and 31P NMR spectral studies. The crystal structure and morphology of the hybrid complexes was investigated with the help of X-ray powder diffraction (XRPD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The thermal properties of 1a-c and 2a-c were studied by thermogravimetric (TG) analysis. The electrochemical behaviour of the complexes reveals that all complexes displayed a quasireversible redox behaviour corresponding to Ru(II)/Ru(III) and Ni(II)/Ni(III) couples for 1a-c and only Ru(II)/Ru(III) couple for 2a-c. All complexes are emissive in solution at room temperature revealing the influence of substituents and solvent polarity on emission properties of the complexes.

New five coordinated supramolecular structured cadmium complex as precursor for CdO nanoparticles: Synthesis, crystal structure, theoretical and 3D Hirshfeld surface analyses

NASA Astrophysics Data System (ADS)

Ghanbari Niyaky, S.; Montazerozohori, M.; Masoudiasl, A.; White, J. M.

2017-03-01

In this paper, a combined experimental and theoretical study on a new CdLBr2 complex (L = N1-(2-bromobenzylidene)-N2-(2-((E)-(2-bromobenzylidene) amino)ethyl) ethane-1,2-diamine) synthesized via template method, is described. The crystal structure analysis of the complex indicates that, the Cd(II) ion is centered in a distorted square pyramidal space constructed by three iminic nitrogens of the ligand as well as two bromide anions. More analysis of crystal packing proposed a supramolecular structure stabilized by some non-covalent interactions such as Br⋯Br and Xsbnd H⋯Br (X = N and C) in solid state. Furthermore, 3D Hirshfeld surface analyses and DFT studies were applied for theoretical investigation of the complexes. Theoretical achievements were found in a good agreement with respect to the experimental data. To evaluate the nature of bonding and the strength of the intra and inter-molecular interactions a natural bond orbital (NBO) analysis on the complex structure was performed. Time dependent density functional theory (TD-DFT) was also applied to predict the electronic spectral data of the complex as compared with the experimental ones. CdLBr2 complex as nano-structure compound was also prepared under ultrasonic conditions and characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD). Finally, it was found that the cadmium complex can be used as a suitable precursor for preparation of CdO nanoparticles via calcination process at 600 °C under air atmosphere.

Assessment of ferrous chloride and Portland cement for the remediation of chromite ore processing residue.

PubMed

Jagupilla, Santhi C; Wazne, Mahmoud; Moon, Deok Hyun

2015-10-01

Chromite Ore Processing Residue (COPR) is an industrial waste containing up to 7% chromium (Cr) including up to 5% hexavalent chromium [Cr(VI)]. The remediation of COPR has been challenging due to the slow release of Cr(VI) from a clinker like material and thereby the incomplete detoxification of Cr(VI) by chemical reagents. The use of sulfur based reagents such as ferrous sulfate and calcium polysulfide to detoxify Cr(VI) has exasperated the swell potential of COPR upon treatment. This study investigated the use of ferrous chloride alone and in combination with Portland cement to address the detoxification of Cr(VI) in COPR and the potential swell of COPR. Chromium regulatory tests, X-ray powder diffraction (XRPD) analyses and X-ray absorption near edge structure (XANES) analyses were used to assess the treatment results. The treatment results indicated that Cr(VI) concentrations for the acid pretreated micronized COPR as measured by XANES analyses were below the New Jersey Department of Environmental Protection (NJDEP) standard of 20 mg kg(-1). The Toxicity characteristic leaching procedure (TCLP) Cr concentrations for all acid pretreated samples also were reduced below the TCLP regulatory limit of 5 mg L(-1). Moreover, the TCLP Cr concentration for the acid pretreated COPR with particle size ⩽0.010 mm were less than the universal treatment standard (UTS) of 0.6 mg L(-1). The treatment appears to have destabilized all COPR potential swell causing minerals. The unconfined compressive strength (UCS) for the treated samples increased significantly upon treatment with Portland cement. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

NASA Astrophysics Data System (ADS)

Kaludjerovic, Lazar; Tomic, Zorica; Djurovic, Rada; Milosevic, Maja

2016-04-01

Pesticides are recognized as an important source of potential pollution to soil and water due to their mobility and degradation in soils. Results presented in this paper show impact of the organic complex concentration on the adsorption of herbicides (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina, located near Boljevac municipality, was used for organic modification. Cation-exchange capacity of this montmorillonite was determined by extraction with ammonium acetate (86 mmol/100g of clay). Montmorillonite have been modified first with NaCl and than with two organic complexes, hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium chloride (PTMA). For both organic complexes, three saturation concentrations were selected for monitoring of the herbicide adsorption (43 mmol/100g of clay (0.5 CEC), 86 mmol/100g of clay (1 CEC) and 129 mmol/100g of clay (1.5 CEC)). Changes in the properties of the inorganic and organic bentonite have been examined using the X-ray powder diffraction (XRPD) and batch equilibrium method. Increase in basal spacing (d) of montmorillonites saturated with 1.5 CEC of organic cation indicate that sorption of PTMA and HDTMA can exceed the saturation of 1 CEC. Both organic montmorillonites have shown higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, (presented in the form of log Kf and 1/n), it can be seen that the sorption decreases in the series: 0.5CEC> 1CEC> 1.5CEC> NaM, for both organic montmorillonites.

Spatiotemporal optical pulse transformation by a resonant diffraction grating

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

Golovastikov, N. V.; Bykov, D. A., E-mail: bykovd@gmail.com; Doskolovich, L. L., E-mail: leonid@smr.ru

The diffraction of a spatiotemporal optical pulse by a resonant diffraction grating is considered. The pulse diffraction is described in terms of the signal (the spatiotemporal incident pulse envelope) passage through a linear system. An analytic approximation in the form of a rational function of two variables corresponding to the angular and spatial frequencies has been obtained for the transfer function of the system. A hyperbolic partial differential equation describing the general form of the incident pulse envelope transformation upon diffraction by a resonant diffraction grating has been derived from the transfer function. A solution of this equation has beenmore » obtained for the case of normal incidence of a pulse with a central frequency lying near the guided-mode resonance of a diffraction structure. The presented results of numerical simulations of pulse diffraction by a resonant grating show profound changes in the pulse envelope shape that closely correspond to the proposed theoretical description. The results of the paper can be applied in creating new devices for optical pulse shape transformation, in optical information processing problems, and analog optical computations.« less

Diffractive interference optical analyzer (DiOPTER)

NASA Astrophysics Data System (ADS)

Sasikumar, Harish; Prasad, Vishnu; Pal, Parama; Varma, Manoj M.

2016-03-01

This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6x10-7 RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4x10-4 RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products.

Diffraction-based optical correlator

NASA Technical Reports Server (NTRS)

Spremo, Stevan M. (Inventor); Fuhr, Peter L. (Inventor); Schipper, John F. (Inventor)

2005-01-01

Method and system for wavelength-based processing of a light beam. A light beam, produced at a chemical or physical reaction site and having at least first and second wavelengths, ?1 and ?2, is received and diffracted at a first diffraction grating to provide first and second diffracted beams, which are received and analyzed in terms of wavelength and/or time at two spaced apart light detectors. In a second embodiment, light from first and second sources is diffracted and compared in terms of wavelength and/or time to determine if the two beams arise from the same source. In a third embodiment, a light beam is split and diffracted and passed through first and second environments to study differential effects. In a fourth embodiment, diffracted light beam components, having first and second wavelengths, are received sequentially at a reaction site to determine whether a specified reaction is promoted, based on order of receipt of the beams. In a fifth embodiment, a cylindrically shaped diffraction grating (uniform or chirped) is rotated and translated to provide a sequence of diffracted beams with different wavelengths. In a sixth embodiment, incident light, representing one or more symbols, is successively diffracted from first and second diffraction gratings and is received at different light detectors, depending upon the wavelengths present in the incident light.

Instrument and method for focusing X-rays, gamma rays and neutrons

DOEpatents

Smither, Robert K.

1984-01-01

A crystal diffraction instrument or diffraction grating instrument with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the crystalline structure, by assembling a plurality of crystalline structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal diffraction case.

Instrument and method for focusing x rays, gamma rays, and neutrons

DOEpatents

Smither, R.K.

1982-03-25

A crystal-diffraction instrument or diffraction-grating instrument is described with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the line structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam, or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal-diffraction case.

Enhanced dissolution and stability of adefovir dipivoxil by cocrystal formation.

PubMed

Gao, Yuan; Zu, Hui; Zhang, Jianjun

2011-04-01

The objectives of this study were to prepare and characterize the novel adefovir dipivoxil-saccharin cocrystal and to demonstrate the enhanced dissolution and stability of adefovir dipivoxil by cocrystal formation. Adefovir dipivoxil-saccharin cocrystal was prepared using a novel solution crystallization approach and scaled up to 30 g for subsequent studies. DSC, IR and XRPD were used to characterize the novel solid form. The stoichiometry of the cocrystal was analysed by HPLC. Dissolution and chemical stability were assessed and compared with marketed adefovir dipivoxil (form 1) used in marketed Hepsera Tablets. A new solid adefovir dipivoxil-saccharin cocrystal with unique melting point, DSC, FTIR and XRPD data was obtained. The molar ratio of adefovir dipivoxil and saccharin in the cocrystal was determined to be 1 : 1. The cocrystal had a pH-independent dissolution profile and showed a two-fold increase in the dissolution efficiency in water and phosphate buffer (pH 6.8) compared with adefovir dipivoxil. The cocrystal was kinetically much more stable than form 1. Form 1 degraded almost completely at 60°C in 18 days, while adefovir dipivoxil-saccharin cocrystal remained unchanged for 47 days at 60°C. This study demonstrated that the dissolution and stability of adefovir dipivoxil could be significantly enhanced by its cocrystal formation with saccharin. The use of cocrystals could be a feasible and valuable approach for improving the physicochemical properties of adefovir dipivoxil. © 2011 The Authors. JPP © 2011 Royal Pharmaceutical Society.

Measurement of Neutrino-Induced Coherent Pion Production and the Diffractive Background in MINERvA

NASA Astrophysics Data System (ADS)

Gomez, Alicia; Minerva Collaboration

2015-04-01

Neutrino-induced coherent charged pion production is a unique neutrino-nucleus scattering process in which a muon and pion are produced while the nucleus is left in its ground state. The MINERvA experiment has made a model-independent differential cross section measurement of this process on carbon by selecting events with a muon and a pion, no evidence of nuclear break-up, and small momentum transfer to the nucleus | t | . A similar process which is a background to the measurement on carbon is diffractive pion production off the free protons in MINERvA's scintillator. This process is not modeled in the neutrino event generator GENIE. At low | t | these events have a similar final state to the aforementioned process. A study to quantify this diffractive event contribution to the background is done by emulating these diffractive events by reweighting all other GENIE-generated background events to the predicted | t | distribution of diffractive events, and then scaling to the diffractive cross section.

Employment of Adaptive Learning Techniques for the Discrimination of Acoustic Emissions.

DTIC Science & Technology

1983-11-01

Dereverberation Simulations ... ............ .. 96 Ŗ 4. ARRAY OPTIMIZATION ......... ...................... . 115 * 4.1 Phased Array Fundamentals... 115 4.2 Phased Array Diffraction Suboptimization ......... ... 121 , .i Page s 4.3 Diffraction Pattern Simulations of Phased Arrays...by differentiating (2.13.14) with respect to z and • -- equating equal powers of z , giving n-i c n bn + I/n kckbn-k (2.13.15)nk= This is very

A structural investigation into the compaction behavior of pharmaceutical composites using powder X-ray diffraction and total scattering analysis.

PubMed

Moore, Michael D; Steinbach, Alison M; Buckner, Ira S; Wildfong, Peter L D

2009-11-01

To use advanced powder X-ray diffraction (PXRD) to characterize the structure of anhydrous theophylline following compaction, alone, and as part of a binary mixture with either alpha-lactose monohydrate or microcrystalline cellulose. Compacts formed from (1) pure theophylline and (2) each type of binary mixture were analyzed intact using PXRD. A novel mathematical technique was used to accurately separate multi-component diffraction patterns. The pair distribution function (PDF) of isolated theophylline diffraction data was employed to assess structural differences induced by consolidation and evaluated by principal components analysis (PCA). Changes induced in PXRD patterns by increasing compaction pressure were amplified by the PDF. Simulated data suggest PDF dampening is attributable to molecular deviations from average crystalline position. Samples compacted at different pressures were identified and differentiated using PCA. Samples compacted at common pressures exhibited similar inter-atomic correlations, where excipient concentration factored in the analyses involving lactose. Practical real-space structural analysis of PXRD data by PDF was accomplished for intact, compacted crystalline drug with and without excipient. PCA was used to compare multiple PDFs and successfully differentiated pattern changes consistent with compaction-induced disordering of theophylline as a single component and in the presence of another material.

Diffraction-based BioCD biosensor for point-of-care diagnostics

NASA Astrophysics Data System (ADS)

Choi, H.; Chang, C.; Savran, C.; Nolte, D.

2018-02-01

The BioCD platform technology uses spinning-disk interferometry to detect molecular binding to target molecular probes in biological samples. Interferometric configurations have included differential phase contrast and in-line quadrature detection. For the detection of extremely low analyte concentrations, nano- or microparticles can enhance the signal through background-free diffraction detection. Diffraction signal measurements on BioCD biosensors are achieved by forming gratings on a disc surface. The grating pattern was printed with biotinylated bovine serum albumin (BSA) and streptavidin coated beads were deployed. The diameter of the beads was 1 micron and strong protein bonding occurs between BSA and streptavidin-coated beads at the printed location. The wavelength for the protein binding detection was 635 nm. The periodic pattern on the disc amplified scattered light into the first-order diffraction position. The diffracted signal contains Mie scattering and a randomly-distributed-bead noise contributions. Variation of the grating pattern periodicity modulates the diffraction efficiency. To test multiple spatial frequencies within a single scan, we designed a fan-shaped grating to perform frequency filter multiplexing on a diffraction-based BioCD.

Monitoring Natural Occurring Asbestos in ophiolite sequences and derived soils: implication with human activities

NASA Astrophysics Data System (ADS)

Punturo, Rosalda; Bloise, Andrea; Cirrincione, Rosolino

2016-04-01

The present contribution focuses on soils that developed on serpentinite-metabasite bedrocks, which could potentially be rich in asbestos minerals and, as a consequence, have a negative impact on agricultural activity and on environmental quality. In order to investigate the natural occurrences of asbestos (NOA) on the surface of the soil formed from serpentinites and metabasite, we selected a study area located in Sila Piccola (Calabrian Peloritani Orogen, southern Italy), where previous studies highlighted the presence of asbestiform minerals within the large ophiolitic sequences that crop out (Punturo et al., 2015; Bloise et al., 2015). Agricultural soil samples have been collected mainly close to urban centres and characterized by using different analytical techniques such as X-ray powder diffraction (XRPD), transmission electron microscopy combined with energy dispersive spectrometry (TEM-EDS), thermogravimetry (TG) and differential scanning calorimetry (DSC) Results pointed out as all the collected soil samples contain serpentine minerals (e.g., chrysotile), asbestos amphiboles, clays, chlorite, muscovite, plagioclase and iron oxides in various amounts. Electron microscope images of the soils show that their contain a variety of aggregating agents such as organic matter and clay in which individual fibres of chrysotile and tremolite-actinolite are trapped. The investigation showed that both serpentinite and metabasite rocks act as a perennial source of contamination for the agriculture lands because of the high amount of tremolite-actinolite found in the studied soil samples developed on such lithotypes. Even if asbestiform minerals usually occur in aggregates which cannot be suspended in the air, agricultural activities such as plowing can destroy these soil aggregates with the creation of dust containing inhalable asbestos fibres that evolve into airborne increasing the exposure of population to them. Since the dispersion of fibres could be associated with carcinogenic lung cancer, in our opinion further research is required to investigate the variation in the asbestos content in soils with increase in distance from serpentinites outcrops, in order to assess the non-occupational lifelong exposure of population to Natural Occurring Asbestos. References Punturo R., Bloise A., Critelli T., Catalano M., Fazio E., and Apollaro C. (2015). Environmental implications related to natural asbestos occurrences in the ophiolites of the Gimigliano-Mount Reventino unit (Calabria, southern Italy). Intern. J. of Environmental Research, 9(2), 405-418. Bloise A., Punturo R., Catalano M., Miriello D., and Cirrincione R. (2016). Naturally occurring asbestos (NOA) in rock and soil and relation with human activities: the monitoring example of selected sites in Calabria (southern Italy) Ital. J. Geosci., 135, 2, (doi: 10.3301/IJG.2015.24).

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

Jenkovszky, L. L., E-mail: jenk@bitp.kiev.ua; Kuprash, O. E., E-mail: oleg.kuprash@desy.de; Orava, R., E-mail: risto.orava@cern.ch

The cross sections for single and double diffraction dissociation at low missing masses are calculated for the LHC energies on the basis of the dual (Regge) model under the assumption of a dominant contribution of the exchange of the Pomeron Regge pole. The model reproduces the rich resonance structure in the region of low missing masses M{sub x}. Diffractively excited states lie on the nucleon trajectory M{sub x} supplemented with the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing-mass dependence of the differential and integrated single and double diffraction dissociation in the kinematical range of presentmore » and future LHC measurements are given.« less

Static strength of molybdenum to 92 GPa under radial X-ray diffraction

NASA Astrophysics Data System (ADS)

Xiong, L.; Tu, P.; Li, B.; Wu, S. Y.; Hao, J. B.; Bai, L. G.; Li, X. D.; Liu, J.

2018-06-01

The high-pressure strength of molybdenum (Mo) to 92 GPa has been studied by radial X-ray diffraction (RXRD) technique. The ratio of t/G is found to decrease above ˜24 GPa, showing the yield of Mo which is caused by plastic deformation at this pressure. Combined with high-pressure shear modulus, it was found that the differential stress corresponding to the yield of Mo at 24 GPa due to plastic deformation is 1.73 GPa. The second increase of t values occurs after ˜66 GPa, suggesting the strength of Mo with a differential stress of ˜1.93 GPa. In addition, the maximum difference stress of molybdenum at 87 GPa is 3.01 GPa.

New detoxification processes for asbestos fibers in the environment.

PubMed

Turci, Francesco; Colonna, Massimiliano; Tomatis, Maura; Mantegna, Stefano; Cravotto, Giancarlo; Fubini, Bice

2010-01-01

Airborne asbestos fibers are associated with many serious detrimental effects on human health, while the hazard posed by waterborne fibers remains an object of debate. In adopting a precautionary principle, asbestos content in water needs to be kept as low as possible and polluting waters with asbestos should be avoided. Turci et al. (2008) recently reported a method for the decontamination of asbestos-polluted waters or landfill leachates from chrysotile that combines power ultrasound (US) with oxalic acid (Ox), an acidic chelating molecule. In the previous study, the occurrence of antigorite, a polymorph of serpentine, the mineral group encompassing chrysotile asbestos, acted as a confounding factor for complete removal of chrysotile from water. The effects of US + Ox on pure chrysotile asbestos from Val Malenco, Italian Central Alps, were examined in this investigation. In the absence of mineral contaminants, a more rapid removal of pure chrysotile from water was undertaken with respect to the previous specimen. After only 12 h of combined US + Ox acid treatment, imaging (SEM) of mineral debris indicated complete loss of fibrous habit. In addition, crystallography and vibrational features of chrysotile were not detectable (x-ray powder diffraction [XRPD] and micro-Raman spectroscopy) and elemental analysis showed a low Mg/Si ratio, i.e., the loss of the brucitic layer in chrysotile (x-ray fluorescence, XRF). Some nanometric rod-shaped debris, observed in the previous study and tentatively recognized as serpentine antigorite, was now found to be made of amorphous silica, which is relatively safe and noncarcinogenic to humans, providing further assurance regarding the safety of treated product. Thus, data indicated the proposed method was effective in detoxifying waterborne chrysotile asbestos fibers.

Effects of source rocks, soil features and climate on natural gamma radioactivity in the Crati valley (Calabria, Southern Italy).

PubMed

Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; De Rosa, Rosanna; Scarciglia, Fabio; Buttafuoco, Gabriele

2016-05-01

The study, which represents an innovative scientific strategy to approach the study of natural radioactivity in terms of spatial and temporal variability, was aimed to characterize the background levels of natural radionuclides in soil and rock in the urban and peri-urban soil of a southern Italy area; to quantify their variations due to radionuclide bearing minerals and soil properties, taking into account nature and extent of seasonality influence. Its main novelty is taking into account the effect of climate in controlling natural gamma radioactivity as well as analysing soil radioactivity in terms of soil properties and pedogenetic processes. In different bedrocks and soils, activities of natural radionuclides ((238)U, (232)Th (4) K) and total radioactivity were measured at 181 locations by means of scintillation γ-ray spectrometry. In addition, selected rocks samples were collected and analysed, using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) and an X-Ray Powder Diffraction (XRPD), to assess the main sources of radionuclides. The natural-gamma background is intimately related to differing petrologic features of crystalline source rocks and to peculiar pedogenetic features and processes. The radioactivity survey was conducted during two different seasons with marked changes in the main climatic characteristics, namely dry summer and moist winter, to evaluate possible effects of seasonal climatic variations and soil properties on radioactivity measurements. Seasonal variations of radionuclides activities show their peak values in summer. The activities of (238)U, (232)Th and (4) K exhibit a positive correlation with the air temperature and are negatively correlated with precipitations. Copyright © 2016 Elsevier Ltd. All rights reserved.

New water soluble heterometallic complex showing unpredicted coordination modes of EDTA

NASA Astrophysics Data System (ADS)

Mudsainiyan, R. K.; Jassal, A. K.; Chawla, S. K.

2015-10-01

A mesoporous 3D polymeric complex (I) having formula {[Zr(IV)O-μ3-(EDTA)Fe(III)OH]·H2O}n has been crystallized and characterized by various techniques. Single-crystal X-ray diffraction analysis revealed that complex (I) crystallized in chiral monoclinic space group Cc (space group no. 9) with unexpected coordination modes of EDTA and mixture of two transition metal ions. In this complex, the coordination number of Zr(IV) ion is seven where four carboxylate oxygen atoms, two nitrogen atoms, one oxide atom are coordinating with Zr(IV). Fe(III) is four coordinated and its coordination environment is composed of three different carboxylic oxygen atoms from three different EDTA and one oxygen atom of -OH group. The structure consists of 4-c and 16-c (2-nodal) net with new topology and point symbol for net is (336·454·530)·(36). TGA study and XRPD pattern showed that the coordination polymer is quite stable even after losing water molecule and -OH ion. Quenching behavior in fluorescence of ligand is observed by complexation with transition metal ions is due to n-π* transition. The SEM micrograph shows the morphology of complex (I) exhibits spherical shape with size ranging from 50 to 280 nm. The minimum N2 (SBET=8.7693 m2/g) and a maximum amount of H2 (high surface area=1044.86 m2/g (STP)) could be adsorbed at 77 K. From DLS study, zeta potential is calculated i.e. -7.94 shows the negative charges on the surface of complex. Hirshfeld surface analysis and fingerprint plots revealed influence of weak or non bonding interactions in crystal packing of complex.

Structural variability in Cu(I) and Ag(I) coordination polymers with a flexible dithione ligand: Synthesis, crystal structure, microbiological and theoretical studies

NASA Astrophysics Data System (ADS)

Beheshti, Azizolla; Nozarian, Kimia; Babadi, Susan Soleymani; Noorizadeh, Siamak; Motamedi, Hossein; Mayer, Peter; Bruno, Giuseppe; Rudbari, Hadi Amiri

2017-05-01

Two new compounds namely [Cu(SCN)(μ-L)]n (1) and {[Ag (μ2-L)](ClO4)}n (2) have been synthesized at room temperature by one-pot reactions between the 1,1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole- 2-thione) (L) and appropriate copper(I) and silver(I) salts. These polymers have been characterized by single crystal X-ray diffraction, XRPD, TGA, elemental analysis, infrared spectroscopy, antibacterial activity and scanning probe microscopy studies. In the crystal structure of 1, copper atoms have a distorted trigonal planar geometry with a CuS2N coordination environment. Each of the ligands in the structure of 1 acting as a bidentate S-bridging ligand to form a 1D chain structure. Additionally, the adjacent 1D chains are interconnected by the intermolecular C-H…S interactions to create a 2D network structure. In contrast to 1, in the cationic 3D structure of 2 each of the silver atoms exhibits an AgS4 tetrahedral geometry with 4-membered Ag2S2 rings. In the structure of 2, the flexible ligand adopts two different conformations; gauche-anti-gauche and anti-anti-anti. The antibacterial studies of these polymers showed that polymer 2 is more potent antibacterial agent than 1. Scanning probe microscopy (SPM) study of the treated bacteria was carried out to investigate the structural changes cause by the interactions between the polymers and target bacteria. Theoretical study of polymer 1 investigated by the DFT calculations indicates that observed transitions at 266 nm and 302 nm in the UV-vis spectrum could be attributed to the π→π* and MLCT transitions, respectively.

Assembly and property research on seven 0D-3D complexes derived from imidazole dicarboxylate and 1,2-bi(pyridin-4-yl)ethene

NASA Astrophysics Data System (ADS)

Mu, Bao; Li, Qian; Lv, Lei; Yang, Dan-Dan; Wang, Qing; Huang, Ru-Dan

2015-03-01

The hydrothermal reaction of transition metals, 1H-imidazole-4,5-dicarboxylic acid (H3ImDC) and 1,2-bi(pyridin-4-yl)ethene (bpe) affords a series of new complexes, namely, [Mn(HImDC)(bpe)(H2O)] (1), [M(H2ImDC)2(H2O)2]·(bpe) (M=Fe(2), Co(3), Zn(4), Cd(6)), [Zn3(ImDC)2(bpe)(H2O)]·3H2O (5) and [Cd(H2ImDC)(bpe)] (7), which are characterized by elemental analyses, IR, TG, XRPD and single crystal X-ray diffraction. Complex 1 exhibits a one dimensional (1D) zigzag chain with two types of irregular rings, and the 1D chains are linked to form a three dimensional (3D) supramolecular framework by the hydrogen bonding interactions (O-H•••O and O-H•••N). Complexes 2-4 and 6 are isomorphous, and they display the mononuclear structures. In these complexes, the O-H•••O and O-H•••N hydrogen bonds play an important role in sustaining the whole 3D supramolecular frameworks. Complex 5 shows a (3,3)-connected 3D framework with (103) topology, and the lattice water molecules as guest molecules exist in the 3D framework. Complex 7 is a wave-like two dimensional (2D) structure, in which the adjacent 1D chains point at the opposite directions. Moreover, the fluorescent properties of complexes 1-7 and the magnetic property of 1 have been investigated. The water vapor adsorption for complex 5 has been researched at 298 K.

Dijet production in $$\\sqrt{s}$$ = 7 TeV $pp$ collisions with large rapidity gaps at the ATLAS experiment

DOE PAGES

Aad, G.

2016-01-18

A 6.8 nb -1 sample of pp collision data collected under low-luminosity conditions at √s = 7 TeV by the ATLAS detector at the Large Hadron Collider is used to study diffractive dijet production. Events containing at least two jets with p T > 20 GeV are selected and analysed in terms of variables which discriminate between diffractive and non-diffractive processes. Cross sections are measured differentially in Δη F, the size of the observable forward region of pseudorapidity which is devoid of hadronic activity, and in an estimator, ξ¯, of the fractional momentum loss of the proton assuming single diffractivemore » dissociation (pp → pX). Model comparisons indicate a dominant non-diffractive contribution up to moderately large Δη F and small ξ¯, with a diffractive contribution which is significant at the highest Δη F and the lowest ξ¯. As a result, the rapidity-gap survival probability is estimated from comparisons of the data in this latter region with predictions based on diffractive parton distribution functions.« less

X-ray diffraction studies of phase transformations in heavy-metal fluoride glasses

NASA Technical Reports Server (NTRS)

Bansal, N. P.; Doremus, R. H.

1985-01-01

Powder X-ray diffraction and differential scanning calorimetry studies of the crystallization properties of five ZrF4-based glass compositions have indicated that the crystalline phase in Zr-Ba-La-Pb fluoride glass is beta-BaZrF6; no such identification of crystal phases was obtainable, however, for the other glasses. Reversible polymorphic phase transformations occur in Zr-Ba-La-Li and Zr-Ba-La-Na fluoride glasses, upon heating to higher temperatures.

Influence of quantum diffraction and shielding on electron-ion collision in two-component semiclassical plasmas

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

Hong, Woo-Pyo; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr; Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791

2015-01-15

The influence of quantum diffraction and shielding on the electron-ion collision process is investigated in two-component semiclassical plasmas. The eikonal method and micropotential taking into account the quantum diffraction and shielding are used to obtain the eikonal scattering phase shift and the eikonal collision cross section as functions of the collision energy, density parameter, Debye length, electron de Broglie wavelength, and the impact parameter. The result shows that the quantum diffraction and shielding effects suppress the eikonal scattering phase shift as well as the differential eikonal collision cross section, especially, in small-impact parameter regions. It is also shown that themore » quantum shielding effect on the eikonal collision cross section is more important in low-collision energies. In addition, it is found that the eikonal collision cross section increases with an increase in the density parameter. The variations of the eikonal cross section due to the quantum diffraction and shielding effects are also discussed.« less

Lunar sample contracts

NASA Technical Reports Server (NTRS)

Walker, R. M.

1974-01-01

The major scientific accomplishments through 1971 are reported for the particle track studies of lunar samples. Results are discussed of nuclear track measurements by optical and electron microscopy, thermoluminescence, X-ray diffraction, and differential thermal analysis.

Incorporation of interfacial roughness into recursion matrix formalism of dynamical X-ray diffraction in multilayers and superlattices.

PubMed

Lobach, Ihar; Benediktovitch, Andrei; Ulyanenkov, Alexander

2017-06-01

Diffraction in multilayers in the presence of interfacial roughness is studied theoretically, the roughness being considered as a transition layer. Exact (within the framework of the two-beam dynamical diffraction theory) differential equations for field amplitudes in a crystalline structure with varying properties along its surface normal are obtained. An iterative scheme for approximate solution of the equations is developed. The presented approach to interfacial roughness is incorporated into the recursion matrix formalism in a way that obviates possible numerical problems. Fitting of the experimental rocking curve is performed in order to test the possibility of reconstructing the roughness value from a diffraction scan. The developed algorithm works substantially faster than the traditional approach to dealing with a transition layer (dividing it into a finite number of thin lamellae). Calculations by the proposed approach are only two to three times longer than calculations for corresponding structures with ideally sharp interfaces.

Effect of different conventional melt quenching technique on purity of lithium niobate (LiNbO3) nano crystal phase formed in lithium borate glass

NASA Astrophysics Data System (ADS)

Kashif, Ismail; Soliman, Ashia A.; Sakr, Elham M.; Ratep, Asmaa

2012-01-01

The glass system (45Li2O + 45B2O3 + 10Nb2O5) was fabricated by the conventional melt quenching technique poured in water, at air, between two hot plates and droplets at the cooled surface. The glass and glass ceramics were studied by differential thermal analysis (DTA) and X-ray diffraction (XRD). The as quenched samples poured in water and between two hot plates were amorphous. The samples poured at air and on cooled surface were crystalline as established via X-ray powder diffraction (XRD) studies. Differential thermal analysis was measured. The glass transition temperature (Tg) and the crystallization temperatures were calculated. Lithium niobate (LiNbO3) was the main phase in glass ceramic poured at air, droplets at the cooled surface and the heat treated glass sample at 500, 540 and 580 °C in addition to traces from LiNb3O8. Crystallite size of the main phases determined from the X-ray diffraction peaks is in the range of <100 nm. The fraction of crystalline (LiNbO3) phase decreases with increase in the heat treatment temperature.

Differentiation Between Organic and Non-Organic Apples Using Diffraction Grating and Image Processing-A Cost-Effective Approach.

PubMed

Jiang, Nanfeng; Song, Weiran; Wang, Hui; Guo, Gongde; Liu, Yuanyuan

2018-05-23

As the expectation for higher quality of life increases, consumers have higher demands for quality food. Food authentication is the technical means of ensuring food is what it says it is. A popular approach to food authentication is based on spectroscopy, which has been widely used for identifying and quantifying the chemical components of an object. This approach is non-destructive and effective but expensive. This paper presents a computer vision-based sensor system for food authentication, i.e., differentiating organic from non-organic apples. This sensor system consists of low-cost hardware and pattern recognition software. We use a flashlight to illuminate apples and capture their images through a diffraction grating. These diffraction images are then converted into a data matrix for classification by pattern recognition algorithms, including k -nearest neighbors ( k -NN), support vector machine (SVM) and three partial least squares discriminant analysis (PLS-DA)- based methods. We carry out experiments on a reasonable collection of apple samples and employ a proper pre-processing, resulting in a highest classification accuracy of 94%. Our studies conclude that this sensor system has the potential to provide a viable solution to empower consumers in food authentication.

Passive millimeter wave differential interference contrast polarimetry

DOEpatents

Bernacki, Bruce E; Kelly, James F; Sheen, David M; Tedeschi, Jonathan R; Hall, Thomas E; Hatchell, Brian K; Valdez, Patrick; McMakin, Douglas L

2014-04-29

Differential polarization imaging systems include an axicon configured to provide a displacement of ray bundles associated with different image patches. The displaced ray bundles are directed to antenna horns and orthomode transducers so as to provide outputs correspond to orthogonal linear states of polarization (SOPs). The outputs are directed to a differential radiometer so that Stokes parameter differences between image patches can be obtained. The ray bundle displacements can be selected to correspond to a mechanical spacing of antenna horns. In some examples, ray bundle displacement corresponds to a displacement less than the diffraction limit.

Crystal structure transformation in potassium acrylate

NASA Astrophysics Data System (ADS)

Pai Verneker, V. R.; Vasanthakumari, R.

1983-10-01

Potassium acrylate undergoes a reversible phase transformation around 335°K with an activation energy of 133 kcal/mole. Differential scanning calorimetry and high temperature X-ray powder diffraction techniques have been used to probe this phenomenon.

Sealed-tube synthesis and phase diagram of Li{sub x}TiS{sub 2} (0 ≤ x ≤1)

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

Zhang, Ziping; National Laboratory for Superconductivity, Institute of Physics, Chinese Academy of Science, Beijing 100190; Dong, Cheng, E-mail: chengdon@aphy.iphy.ac.cn

2015-01-15

Graphical abstract: We reported a new method to prepare Li{sub x}TiS{sub 2} (0 ≤ x ≤ 1) at 600 °C in sealed tube using Li{sub 2}S aslithium source. A schematic phase diagram of the Li{sub x}TiS{sub 2} system has been constructed based on the DTA and XRD data. - Abstract: We reported a new method to prepare Li{sub x}TiS{sub 2} (0 ≤ x ≤ 1) at 600 °C in sealed tube using Li{sub 2}S as lithium source. The Li{sub x}TiS{sub 2} samples were characterized by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and differential thermal analysis. Themore » variations of the lattice parameters with lithium content x in Li{sub x}TiS{sub 2} were determined by X-ray powder diffraction analysis for both 1T and 3R phases. The phase transition between low-temperature 1T phase and high-temperature 3R phase was confirmed by the powder X-ray diffraction analysis. Based on the differential thermal analysis and X-ray diffraction results, a schematic phase diagram of the Li{sub x}TiS{sub 2} system has been constructed, providing a guideline to synthesize Li{sub x}TiS{sub 2} in 1T structure or 3R structure.« less

Comparison of dislocation content measured with transmission electron microscopy and micro-Laue diffraction based streak analysis

DOE PAGES

Zhang, C.; Balachandran, S.; Eisenlohr, P.; ...

2017-10-04

The subsurface dislocation content in a Ti-5Al-2.5Sn (wt%) uniaxial tension sample deformed at ambient temperature was characterized by peak streak analysis of micro-Laue diffraction patterns collected non-destructively by differential aperture X-raymicroscopy, and with focused ion beam transmission electron microscopy of material in the same volume. This comparison reveals that micro-Laue diffraction streak analysis based on an edge dislocation assumption can accurately identify the dominant dislocation slip system history (Burgers vector and plane observed by TEM), despite the fact that dislocations have predominantly screw character. As a result, other dislocations identified by TEM were not convincingly discernible from the peak streakmore » analysis.« less

Comparison of dislocation content measured with transmission electron microscopy and micro-Laue diffraction based streak analysis

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

Zhang, C.; Balachandran, S.; Eisenlohr, P.

The subsurface dislocation content in a Ti-5Al-2.5Sn (wt%) uniaxial tension sample deformed at ambient temperature was characterized by peak streak analysis of micro-Laue diffraction patterns collected non-destructively by differential aperture X-raymicroscopy, and with focused ion beam transmission electron microscopy of material in the same volume. This comparison reveals that micro-Laue diffraction streak analysis based on an edge dislocation assumption can accurately identify the dominant dislocation slip system history (Burgers vector and plane observed by TEM), despite the fact that dislocations have predominantly screw character. As a result, other dislocations identified by TEM were not convincingly discernible from the peak streakmore » analysis.« less

Characterization and relevance of physicochemical interactions among components of a novel multiparticulate formulation for colonic delivery.

PubMed

Singh, Brahma N; Kim, Kwon H

2007-08-16

The primary objective of this study was to investigate potential interactions among a model drug (azathioprine; AZA), polymers and a divalent metal ion, which were utilized in the development of a novel multiparticulate formulation for colonic delivery. The approach involved preparation of beads by ionotropic gelation of deacylated gellan gum (DGG) in the presence of Ca(2+) ions, followed by coating with Eudragit S-100. Various possible physicochemical interactions among formulation components were characterized by DSC, FT-IR, XRPD, (1)H-NMR, and an isothermal stress test. Results of isothermal stress testing indicated that there was no significant interaction of AZA with DGG and Eudragit S-100. However, results of DSC and XRPD studies suggested that there could be interactions between AZA and DGG, and ionotropic gelation can affect the physical state of AZA, which may have implications for drug release characteristics and, physical and chemical stability. The results of FT-IR studies were suggestive of interactions of DGG with AZA and Eudragit S-100, and provided evidence for interactions of AZA and DGG with Ca(2+) ions. The electrostatic interaction of DGG with Ca(2+) was also supported by results of DSC studies while that between AZA and Ca(2+) was confirmed by (1)H-NMR studies. This study, to our knowledge, is first reported investigation in which the unique thermal property of gellan gum gels, and possible interactions between a drug and counter ions of an ionotropic agent have been demonstrated through bead characterization studies. The formation of AZA-Ca(2+) complex could have an impact on drug release kinetics, product stability and clinical efficacy for treatment of inflammatory bowel diseases or other diseases, which merit further investigation.

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

Grujić-Brojčin, M., E-mail: myramyra@ipb.ac.rs; Armaković, S.; Tomić, N.

The influence of La-doping in the range of 0.5–6.0 mol% on structural and morphological properties of TiO{sub 2} nanopowders synthesized by sol–gel routine has been investigated by XRPD, AFM, EDS and BET measurements, as well as Raman spectroscopy. The XRPD and Raman measurements have revealed the anatase phase as dominant in all nanopowders, with crystallite size decreasing from ∼ 15 nm in pure TiO{sub 2} to ∼ 12 nm in La-doped samples. The BET data suggest that all samples are fully mesoporous, with mean pore diameters in the range of ∼ 6–8 nm. The specific surface area and the complexitymore » of pore structure are greater in doped samples than in pure TiO{sub 2} sample. The spectroscopic ellipsometry has apparently shown that the band gap has been gradually increased with the increase of La content. The STM and STS techniques have been used successfully to evaluate the surface morphology and electronic properties of La-doped nanopowders. All investigated properties have been related to photocatalytic activity, tested in degradation of a metoprolol tartrate salt (0.05 mM), and induced by UV-radiation. All doped samples showed increased photocatalytic activity compared to pure TiO{sub 2}, among which the 0.65 mol% La-doped sample appeared to be the most efficient. - Highlights: • Effects of La-doping on structural, morphological and electronic properties of TiO{sub 2} nanopowders. • Surface morphology and electronic properties of La-doped nanopowders evaluated by STM/STS. • Spectroscopic ellipsometry shown gradual increase of bandgap with the increase of La content. • Photocatalytic activity of samples was tested in degradation of MET under UV light.« less

A Lower Temperature FDM 3D Printing for the Manufacture of Patient-Specific Immediate Release Tablets.

PubMed

Okwuosa, Tochukwu C; Stefaniak, Dominika; Arafat, Basel; Isreb, Abdullah; Wan, Ka-Wai; Alhnan, Mohamed A

2016-11-01

The fabrication of ready-to-use immediate release tablets via 3D printing provides a powerful tool to on-demand individualization of dosage form. This work aims to adapt a widely used pharmaceutical grade polymer, polyvinylpyrrolidone (PVP), for instant on-demand production of immediate release tablets via FDM 3D printing. Dipyridamole or theophylline loaded filaments were produced via processing a physical mixture of API (10%) and PVP in the presence of plasticizer through hot-melt extrusion (HME). Computer software was utilized to design a caplet-shaped tablet. The surface morphology of the printed tablet was assessed using scanning electron microscopy (SEM). The physical form of the drugs and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC. In vitro drug release studies for all 3D printed tablets were conducted in a USP II dissolution apparatus. Bridging 3D printing process with HME in the presence of a thermostable filler, talc, enabled the fabrication of immediate release tablets at temperatures as low as 110°C. The integrity of two model drugs was maintained following HME and FDM 3D printing. XRPD indicated that a portion of the loaded theophylline remained crystalline in the tablet. The fabricated tablets demonstrated excellent mechanical properties, acceptable in-batch variability and an immediate in vitro release pattern. Combining the advantages of PVP as an impeding polymer with FDM 3D printing at low temperatures, this approach holds a potential in expanding the spectrum of drugs that could be used in FDM 3D printing for on demand manufacturing of individualised dosage forms.

Solid-state, triboelectrostatic and dissolution characteristics of spray-dried piroxicam-glucosamine solid dispersions.

PubMed

Adebisi, Adeola O; Kaialy, Waseem; Hussain, Tariq; Al-Hamidi, Hiba; Nokhodchi, Ali; Conway, Barbara R; Asare-Addo, Kofi

2016-10-01

This work explores the use of both spray drying and d-glucosamine HCl (GLU) as a hydrophilic carrier to improve the dissolution rate of piroxicam (PXM) whilst investigating the electrostatic charges associated with the spray drying process. Spray dried PXM:GLU solid dispersions were prepared and characterised (XRPD, DSC, SEM). Dissolution and triboelectric charging were also conducted. The results showed that the spray dried PXM alone, without GLU produced some PXM form II (DSC results) with no enhancement in solubility relative to that of the parent PXM. XRPD results also showed the spray drying process to decrease the crystallinity of GLU and solid dispersions produced. The presence of GLU improved the dissolution rate of PXM. Spray dried PXM: GLU at a ratio of 2:1 had the most improved dissolution. The spray drying process generally yielded PXM-GLU spherical particles of around 2.5μm which may have contributed to the improved dissolution. PXM showed a higher tendency for charging in comparison to the carrier GLU (-3.8 versus 0.5nC/g for untreated material and -7.5 versus 3.1nC/g for spray dried materials). Spray dried PXM and spray dried GLU demonstrated higher charge densities than untreated PXM and untreated GLU, respectively. Regardless of PXM:GLU ratio, all spray dried PXM:GLU solid dispersions showed a negligible charge density (net-CMR: 0.1-0.3nC/g). Spray drying of PXM:GLU solid dispersions can be used to produce formulation powders with practically no charge and thereby improving handling as well as dissolution behaviour of PXM. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Fabricating a Shell-Core Delayed Release Tablet Using Dual FDM 3D Printing for Patient-Centred Therapy.

PubMed

Okwuosa, Tochukwu C; Pereira, Beatriz C; Arafat, Basel; Cieszynska, Milena; Isreb, Abdullah; Alhnan, Mohamed A

2017-02-01

Individualizing gastric-resistant tablets is associated with major challenges for clinical staff in hospitals and healthcare centres. This work aims to fabricate gastric-resistant 3D printed tablets using dual FDM 3D printing. The gastric-resistant tablets were engineered by employing a range of shell-core designs using polyvinylpyrrolidone (PVP) and methacrylic acid co-polymer for core and shell structures respectively. Filaments for both core and shell were compounded using a twin-screw hot-melt extruder (HME). CAD software was utilized to design a capsule-shaped core with a complementary shell of increasing thicknesses (0.17, 0.35, 0.52, 0.70 or 0.87 mm). The physical form of the drug and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC. A shell thickness ≥0.52 mm was deemed necessary in order to achieve sufficient core protection in the acid medium. The technology proved viable for incorporating different drug candidates; theophylline, budesonide and diclofenac sodium. XRPD indicated the presence of theophylline crystals whilst budesonide and diclofenac sodium remained amorphous in the PVP matrix of the filaments and 3D printed tablets. Fabricated tablets demonstrated gastric resistant properties and a pH responsive drug release pattern in both phosphate and bicarbonate buffers. Despite its relatively limited resolution, FDM 3D printing proved to be a suitable platform for a single-process fabrication of delayed release tablets. This work reveals the potential of dual FDM 3D printing as a unique platform for personalising delayed release tablets to suit an individual patient's needs.

Thermal and structural alternations in CuAlMnNi shape memory alloy by the effect of different pressure applications

NASA Astrophysics Data System (ADS)

Canbay, Canan Aksu; Polat, Tercan

2017-09-01

In this work the effects of the applied pressure on the characteristic transformation temperatures, the high temperature order-disorder phase transitions, the variation in diffraction peaks and the surface morphology of the CuAlMnNi shape memory alloy was investigated. The evolution of the transformation temperatures was studied by differential scanning calorimetry (DSC) with different heating and cooling rates. The differential thermal analysis measurements were performed to obtain the ordered-disordered phase transformations from room temperature to 900 °C. The characteristic transformation temperatures and the thermodynamic parameters were highly sensitive to variations in the applied pressure and also the applied pressure affected the thermodynamic parameters. The activation energy of the sample according to applied pressure values calculated by Kissinger method. The structural changes of the samples were studied by X-ray diffraction (XRD) measurements and by optical microscope observations at room temperature.

Femtosecond time-resolved MeV electron diffraction

DOE PAGES

Zhu, Pengfei; Zhu, Y.; Hidaka, Y.; ...

2015-06-02

We report the experimental demonstration of femtosecond electron diffraction using high-brightness MeV electron beams. High-quality, single-shot electron diffraction patterns for both polycrystalline aluminum and single-crystal 1T-TaS 2 are obtained utilizing a 5 fC (~3 × 10 4 electrons) pulse of electrons at 2.8 MeV. The high quality of the electron diffraction patterns confirms that electron beam has a normalized emittance of ~50 nm rad. The transverse and longitudinal coherence length is ~11 and ~2.5 nm, respectively. The timing jitter between the pump laser and probe electron beam was found to be ~100 fs (rms). The temporal resolution is demonstrated bymore » observing the evolution of Bragg and superlattice peaks of 1T-TaS 2 following an 800 nm optical pump and was found to be 130 fs. Lastly, our results demonstrate the advantages of MeV electrons, including large elastic differential scattering cross-section and access to high-order reflections, and the feasibility of ultimately realizing below 10 fs time-resolved electron diffraction.« less

Single and double diffractive dissociation and the problem of extraction of the proton-Pomeron cross-section

NASA Astrophysics Data System (ADS)

Petrov, V. A.; Ryutin, R. A.

2016-04-01

Diffractive dissociation processes are analyzed in the framework of covariant reggeization. We have considered the general form of hadronic tensor and its asymptotic behavior for t → 0 in the case of conserved tensor currents before reggeization. Resulting expressions for differential cross-sections of single dissociation (SD) process (pp → pM), double dissociation (DD) (pp → M1M2) and for the proton-Pomeron cross-section are given in detail, and corresponding problems of the approach are discussed.

Metastable and equilibrium phase formation in sputter-deposited Ti/Al multilayer thin films

NASA Astrophysics Data System (ADS)

Lucadamo, G.; Barmak, K.; Lavoie, C.; Cabral, C., Jr.; Michaelsen, C.

2002-06-01

The sequence and kinetics of metastable and equilibrium phase formation in sputter deposited multilayer thin films was investigated by combining in situ synchrotron x-ray diffraction (XRD) with ex situ electron diffraction and differential scanning calorimetry (DSC). The sequence included both cubic and tetragonal modifications of the equilibrium TiAl3 crystal structure. Values for the formation activation energies of the various phases in the sequence were determined using the XRD and DSC data obtained here, as well as activation energy data reported in the literature.

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.

Mapping of reciprocal space of La{sub 0.30}CoO{sub 2} in 3D: Analysis of superstructure diffractions and intergrowths with Co{sub 3}O{sub 4}

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

Brázda, Petr, E-mail: brazda@fzu.cz; Palatinus, Lukáš; Klementová, Mariana

2015-07-15

We have used electron diffraction tomography and powder X-ray diffraction to elucidate the structural properties of layered cobaltate γ-La{sub 0.30}CoO{sub 2}. The structure consists of hexagonal sheets of edge-sharing CoO{sub 6} octahedra interleaved by lanthanum monolayers. The La{sup 3+} cations occupy only one third of available P2 sites, forming a 2-dimensional a√3×a√3 superstructure in a–b plane. The results show that there exists no order in the mutual relative shift between the neighbouring La interlayers within the a–b plane. This is manifested in the observed monotonous decrease of the diffracted intensity of the superstructure diffractions along c{sup ⁎} in both X-raymore » and electron diffraction data. The observed lack of stacking order differentiates the La{sub x}CoO{sub 2} from its Ca and Sr analogues where at least a partial stacking order of the cationic interlayers is manifested in experimental data published in literature. - Highlights: • We use electron diffraction tomography for reciprocal space mapping of La{sub 0.30}CoO{sub 2}. • We observed a complete disorder of the stacking of Lanthanum interlayers. • Co{sub 3}O{sub 4} intergrown with La{sub 0.30}CoO{sub 2} crystals brings about fake superstructure diffractions. • Twinning of Co{sub 3}O{sub 4} enhances the problem of fake superstructure diffractions.« less

Neutron and X-ray Microbeam Diffraction Studies around a Fatigue-Crack Tip after Overload

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

Lee, Sooyeol; Barabash, Rozaliya; Chung, Jin-Seok

2008-01-01

An in-situ neutron diffraction technique was used to investigate the lattice-strain distributions and plastic deformation around a crack tip after overload. The lattice-strain profiles around a crack tip were measured as a function of the applied load during the tensile loading cycles after overload. Dislocation densities calculated from the diffraction peak broadening were presented as a function of the distance from the crack tip. Furthermore, the crystallographic orientation variations were examined near a crack tip using polychromatic X-ray microdiffraction combined with differential aperture microscopy. Crystallographic tilts are considerably observed beneath the surface around a crack tip, and these are consistentmore » with the high dislocation densities near the crack tip measured by neutron peak broadening.« less

Correlative Raman spectroscopy and focused ion beam for targeted phase boundary analysis of titania polymorphs

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

Mangum, John S.; Chan, Lisa H.; Schmidt, Ute

Site-specific preparation of specimens using focused ion beam instruments for transmission electron microscopy is at the forefront of targeting regions of interest for nanoscale characterization. Typical methods of pinpointing desired features include electron backscatter diffraction for differentiating crystal structures and energy-dispersive X-Ray spectroscopy for probing compositional variations. Yet there are situations, notably in the titanium dioxide system, where these techniques can fail. Differentiating between the brookite and anatase polymorphs of titania is either excessively laborious or impossible with the aforementioned techniques. However, due to differences in bonding structure, Raman spectroscopy serves as an ideal candidate for polymorph differentiation. In thismore » work, a correlative approach utilizing Raman spectroscopy for targeted focused ion beam specimen preparation was employed. Dark field imaging and diffraction in the transmission electron microscope confirmed the region of interest located via Raman spectroscopy and demonstrated the validity of this new method. Correlative Raman spectroscopy, scanning electron microscopy, and focused ion beam is shown to be a promising new technique for identifying site-specific preparation of nanoscale specimens in cases where conventional approaches do not suffice.« less

Correlative Raman spectroscopy and focused ion beam for targeted phase boundary analysis of titania polymorphs.

PubMed

Mangum, John S; Chan, Lisa H; Schmidt, Ute; Garten, Lauren M; Ginley, David S; Gorman, Brian P

2018-05-01

Site-specific preparation of specimens using focused ion beam instruments for transmission electron microscopy is at the forefront of targeting regions of interest for nanoscale characterization. Typical methods of pinpointing desired features include electron backscatter diffraction for differentiating crystal structures and energy-dispersive X-Ray spectroscopy for probing compositional variations. Yet there are situations, notably in the titanium dioxide system, where these techniques can fail. Differentiating between the brookite and anatase polymorphs of titania is either excessively laborious or impossible with the aforementioned techniques. However, due to differences in bonding structure, Raman spectroscopy serves as an ideal candidate for polymorph differentiation. In this work, a correlative approach utilizing Raman spectroscopy for targeted focused ion beam specimen preparation was employed. Dark field imaging and diffraction in the transmission electron microscope confirmed the region of interest located via Raman spectroscopy and demonstrated the validity of this new method. Correlative Raman spectroscopy, scanning electron microscopy, and focused ion beam is shown to be a promising new technique for identifying site-specific preparation of nanoscale specimens in cases where conventional approaches do not suffice. Copyright © 2018 Elsevier B.V. All rights reserved.

Correlative Raman spectroscopy and focused ion beam for targeted phase boundary analysis of titania polymorphs

DOE PAGES

Mangum, John S.; Chan, Lisa H.; Schmidt, Ute; ...

2018-02-23

Site-specific preparation of specimens using focused ion beam instruments for transmission electron microscopy is at the forefront of targeting regions of interest for nanoscale characterization. Typical methods of pinpointing desired features include electron backscatter diffraction for differentiating crystal structures and energy-dispersive X-Ray spectroscopy for probing compositional variations. Yet there are situations, notably in the titanium dioxide system, where these techniques can fail. Differentiating between the brookite and anatase polymorphs of titania is either excessively laborious or impossible with the aforementioned techniques. However, due to differences in bonding structure, Raman spectroscopy serves as an ideal candidate for polymorph differentiation. In thismore » work, a correlative approach utilizing Raman spectroscopy for targeted focused ion beam specimen preparation was employed. Dark field imaging and diffraction in the transmission electron microscope confirmed the region of interest located via Raman spectroscopy and demonstrated the validity of this new method. Correlative Raman spectroscopy, scanning electron microscopy, and focused ion beam is shown to be a promising new technique for identifying site-specific preparation of nanoscale specimens in cases where conventional approaches do not suffice.« less

Investigation on bandgap, diffraction, interference, and refraction effects of photonic crystal structure in GaN/InGaN LEDs for light extraction.

PubMed

Patra, Saroj Kanta; Adhikari, Sonachand; Pal, Suchandan

2014-06-20

In this paper, we have made a clear differentiation among bandgap, diffraction, interference, and refraction effects in photonic crystal structures (PhCs). For observing bandgap, diffraction, and refraction effects, PhCs are considered on the top p-GaN surface of light emitting diodes (LEDs), whereas for interference effect, hole type PhCs are considered to be embedded within n-GaN layer of LED. From analysis, it is observed that at a particular lattice periodicity, for which bandgap lies within the wavelength of interest shows a significant light extraction due to inhibition of guided mode. Beyond a certain periodicity, diffraction effect starts dominating and light extraction improves further. The interference effect is observed in embedded photonic crystal LEDs, where depth of etching supports constructive interference of outward light waves. We have also shed light on refraction effects exhibited by the PhCs and whether negative refraction properties of PhCs may be useful in case of LED light extraction.

Diffraction of a Gaussian beam in a three-dimensional smoothly inhomogeneous medium: an eikonal-based complex geometrical-optics approach.

PubMed

Berczynski, Pawel; Bliokh, Konstantin Yu; Kravtsov, Yuri A; Stateczny, Andrzej

2006-06-01

We present an ab initio account of the paraxial complex geometrical optics (CGO) in application to scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of the Riccati type. This substantially simplifies the description of Gaussian beam diffraction as compared with full-wave or parabolic (quasi-optics) equations. For a Gaussian beam propagating in a homogeneous medium or along the symmetry axis in a lenslike medium, the CGO equations possess analytical solutions; otherwise, they can be readily solved numerically. As a nontrivial example we consider Gaussian beam propagation and diffraction along a helical ray in an axially symmetric waveguide medium. It is shown that the major axis of the beam's elliptical cross section grows unboundedly; it is oriented predominantly in the azimuthal (binormal) direction and does not obey the parallel-transport law.

Evaluation of Two Computational Techniques of Calculating Multipath Using Global Positioning System Carrier Phase Measurements

NASA Technical Reports Server (NTRS)

Gomez, Susan F.; Hood, Laura; Panneton, Robert J.; Saunders, Penny E.; Adkins, Antha; Hwu, Shian U.; Lu, Ba P.

1996-01-01

Two computational techniques are used to calculate differential phase errors on Global Positioning System (GPS) carrier war phase measurements due to certain multipath-producing objects. The two computational techniques are a rigorous computati electromagnetics technique called Geometric Theory of Diffraction (GTD) and the other is a simple ray tracing method. The GTD technique has been used successfully to predict microwave propagation characteristics by taking into account the dominant multipath components due to reflections and diffractions from scattering structures. The ray tracing technique only solves for reflected signals. The results from the two techniques are compared to GPS differential carrier phase ns taken on the ground using a GPS receiver in the presence of typical International Space Station (ISS) interference structures. The calculations produced using the GTD code compared to the measured results better than the ray tracing technique. The agreement was good, demonstrating that the phase errors due to multipath can be modeled and characterized using the GTD technique and characterized to a lesser fidelity using the DECAT technique. However, some discrepancies were observed. Most of the discrepancies occurred at lower devations and were either due to phase center deviations of the antenna, the background multipath environment, or the receiver itself. Selected measured and predicted differential carrier phase error results are presented and compared. Results indicate that reflections and diffractions caused by the multipath producers, located near the GPS antennas, can produce phase shifts of greater than 10 mm, and as high as 95 mm. It should be noted tl the field test configuration was meant to simulate typical ISS structures, but the two environments are not identical. The GZ and DECAT techniques have been used to calculate phase errors due to multipath o the ISS configuration to quantify the expected attitude determination errors.

Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

DOE PAGES

Xie, Miao; Mohammadi, Reza; Turner, Christopher L.; ...

2015-07-29

In this paper, we explore the hardening mechanisms in WB4-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under nonhydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB 4 solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

Elastic scattering of low energy electrons in partially ionized dense semiclassical plasma

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

Dzhumagulova, K. N., E-mail: dzhumagulova.karlygash@gmail.com; Shalenov, E. O.; Ramazanov, T. S.

2015-08-15

Elastic scattering of electrons by hydrogen atoms in a dense semiclassical hydrogen plasma for low impact energies has been studied. Differential scattering cross sections were calculated within the effective model of electron-atom interaction taking into account the effect of screening as well as the quantum mechanical effect of diffraction. The calculations were carried out on the basis of the phase-function method. The influence of the diffraction effect on the Ramsauer–Townsend effect was studied on the basis of a comparison with results made within the effective polarization model of the Buckingham type.

Stress in recrystallized quartz by electron backscatter diffraction mapping

NASA Astrophysics Data System (ADS)

Llana-Fúnez, S.

2017-07-01

The long-term state of stress at middle and lower crustal depths can be estimated through the study of the microstructure of exhumed rocks from active and/or ancient shear zones. Constitutive equations for deformation mechanisms in experimentally deformed rocks relate differential stress to the size of recrystallized grains. Cross et al. (2017) take advantage of electron backscatter diffraction mapping to systematically separate new recrystallized grains from host grains on the basis of the measurable lattice distorsion within the grains. They produce the first calibrated piezometer for quartz with this technique, reproducing within error a previous calibration based on optical microscopy.

Growth and characterization of metal halide perovskite crystals: Benzyltributyl ammonium tetrachloro manganate(II) monohydrate

NASA Astrophysics Data System (ADS)

Dhandapani, M.; Sugandhi, K.; Nithya, S.; Muthuraja, P.; Balachandar, S.; Aranganayagam, K. R.

2018-05-01

The perovskite type organic-inorganic hybrid benzyltributyl ammoniumtetrachloro manganate (II) monohydrates (BTBA-Mn) are synthesized and the single crystals are grown by slow evaporation solution growth technique. The structure of the grown crystals are confirmed by using X-ray diffraction (XRD), unit cell parameter analysis, Fourier transform Infrared (FTIR), elemental analysis and 13C-NMR spectral studies. Thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning colorimetric (DSC) analysis were carried out to understand thermal stability and occurrence of phase transition.

Construction of noninterpenetrating and interpenetrating Co(ii) networks with halogenated carboxylate modulated by auxiliary N-donor co-ligands: structural diversity, electrochemical and photocatalytic properties.

PubMed

Hao, Shao Yun; Hou, Suo Xia; Van Hecke, Kristof; Cui, Guang Hua

2017-02-14

Six Co(ii)-based coordination polymers (CPs) with characteristic frameworks and topologies-namely, [Co(L1)(DCTP)] n (1), [Co(L2)(DCTP)] n (2), [Co(L3)(DCTP)] n (3), {[Co 3 (L4) 3 (DCTP) 3 ·H 2 O]·H 2 O} n (4), [Co(L5) 1.5 (DCTP)] n (5) and [Co(L6)(DCTP)] n (6)-were successfully hydrothermally synthesized by employing the halogenated linear ligand 2,5-dichloroterephthalic acid (H 2 DCTP). The interpenetrated structures could be rationally modulated by auxiliary N-donor co-ligands containing 1,1'-(1,4-butanediyl)bis-1H-benzimidazole (L1), 1,4-bis(5,6-dimethylbenzimidazol-1-yl)-2-butylene (L2), 1,2-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L3), 1,4-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L4), 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene (L5) and 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene (L6). These diaphanous crystals were clearly characterized by elemental analysis, infrared (IR) spectra and X-ray powder diffraction (XRPD) as well as single-crystal X-ray diffraction analysis. With the aid of the flexible N-donor co-ligands, CP 1 occupies a non-interpenetrated 2D sheet with the point symbol {4 4 ·6 2 } sql net topology, CP 2 possesses a 3D hexagon-shaped network with the point symbol {6 6 } three-fold interpenetrated sqc6 topology, CP 3 exhibits a 2D layer with the point symbol {4 4 ·6 2 } sql net topology, CP 4 reveals an unusual 3D framework with the point symbol {4 2 ·6 3 ·8} three-fold interpenetrated sra topology, CP 5 has a 3D hexagon-shaped network with the point symbol {6 6 } two-fold interpenetrated sqc6 topology, while CP 6 displays a 3D hexagon-shaped network with the point symbol {6 6 } three-fold interpenetrated sqc6 topology. The diverse structures of CPs 1-6 illustrate that the substitute group and position of the methyl group of the bis(benzimidazole) derivatives play a significant role in the assembly of such interpenetrated frameworks. Moreover, luminescence properties and thermal behavior, as well as the electrochemical and photocatalytic properties of CPs 1-6 on the degradation of methylene blue, are also presented.

OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. III. MEASURES BELOW THE DIFFRACTION LIMIT OF THE WIYN TELESCOPE

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

Horch, Elliott P.; Van Altena, William F.; Howell, Steve B.

2011-06-15

In this paper, we study the ability of CCD- and electron-multiplying-CCD-based speckle imaging to obtain reliable astrometry and photometry of binary stars below the diffraction limit of the WIYN 3.5 m Telescope. We present a total of 120 measures of binary stars, 75 of which are below the diffraction limit. The measures are divided into two groups that have different measurement accuracy and precision. The first group is composed of standard speckle observations, that is, a sequence of speckle images taken in a single filter, while the second group consists of paired observations where the two observations are taken onmore » the same observing run and in different filters. The more recent paired observations were taken simultaneously with the Differential Speckle Survey Instrument, which is a two-channel speckle imaging system. In comparing our results to the ephemeris positions of binaries with known orbits, we find that paired observations provide the opportunity to identify cases of systematic error in separation below the diffraction limit and after removing these from consideration, we obtain a linear measurement uncertainty of 3-4 mas. However, if observations are unpaired or if two observations taken in the same filter are paired, it becomes harder to identify cases of systematic error, presumably because the largest source of this error is residual atmospheric dispersion, which is color dependent. When observations are unpaired, we find that it is unwise to report separations below approximately 20 mas, as these are most susceptible to this effect. Using the final results obtained, we are able to update two older orbits in the literature and present preliminary orbits for three systems that were discovered by Hipparcos.« less

Physicochemical characterization and aerosol dispersion performance of organic solution advanced spray-dried cyclosporine A multifunctional particles for dry powder inhalation aerosol delivery

PubMed Central

Wu, Xiao; Zhang, Weifen; Hayes, Don; Mansour, Heidi M

2013-01-01

In this systematic and comprehensive study, inhalation powders of the polypeptide immunosuppressant drug – cyclosporine A – for lung delivery as dry powder inhalers (DPIs) were successfully designed, developed, and optimized. Several spray drying pump rates were rationally chosen. Comprehensive physicochemical characterization and imaging was carried out using scanning electron microscopy, hot-stage microscopy, differential scanning calorimetry, powder X-ray diffraction, Karl Fischer titration, laser size diffraction, and gravimetric vapor sorption. Aerosol dispersion performance was conducted using a next generation impactor with a Food and Drug Administration-approved DPI device. These DPIs displayed excellent aerosol dispersion performance with high values in emitted dose, respirable fraction, and fine particle fraction. In addition, novel multifunctional inhalation aerosol powder formulations of cyclosporine A with lung surfactant-mimic phospholipids were also successfully designed and developed by advanced organic solution cospray drying in closed mode. The lung surfactantmimic phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-snglycero- 3-(phosphor-rac-1-glycerol). These cyclosporine A lung surfactant-mimic aerosol powder formulations were comprehensively characterized. Powder X-ray diffraction and differential scanning calorimetry confirmed that the phospholipid bilayer structure in the solid state was preserved following advanced organic solution spray drying in closed mode. These novel multifunctional inhalation powders were optimized for DPI delivery with excellent aerosol dispersion performance and high aerosol performance parameters. PMID:23569375

Enhanced encapsulation and bioavailability of breviscapine in PLGA microparticles by nanocrystal and water-soluble polymer template techniques.

PubMed

Wang, Hong; Zhang, Guangxing; Ma, Xueqin; Liu, Yanhua; Feng, Jun; Park, Kinam; Wang, Wenping

2017-06-01

Poly (lactide-co-glycolide) (PLGA) microparticles are widely used for controlled drug delivery. Emulsion methods have been commonly used for preparation of PLGA microparticles, but they usually result in low loading capacity, especially for drugs with poor solubility in organic solvents. In the present study, the nanocrystal technology and a water-soluble polymer template method were used to fabricate nanocrystal-loaded microparticles with improved drug loading and encapsulation efficiency for prolonged delivery of breviscapine. Breviscapine nanocrystals were prepared using a precipitation-ultrasonication method and further loaded into PLGA microparticles by casting in a mold from a water-soluble polymer. The obtained disc-like particles were then characterized and compared with the spherical particles prepared by an emulsion-solvent evaporation method. X-ray powder diffraction (XRPD) and confocal laser scanning microscopy (CLSM) analysis confirmed a highly-dispersed state of breviscapine inside the microparticles. The drug form, loading percentage and fabrication techniques significantly affected the loading capacity and efficiency of breviscapine in PLGA microparticles, and their release performance as well. Drug loading was increased from 2.4% up to 15.3% when both nanocrystal and template methods were applied, and encapsulation efficiency increased from 48.5% to 91.9%. But loading efficiency was reduced as the drug loading was increased. All microparticles showed an initial burst release, and then a slow release period of 28days followed by an erosion-accelerated release phase, which provides a sustained delivery of breviscapine over a month. A relatively stable serum drug level for more than 30days was observed after intramuscular injection of microparticles in rats. Therefore, PLGA microparticles loaded with nanocrystals of poorly soluble drugs provided a promising approach for long-term therapeutic products characterized with preferable in vitro and in vivo performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and magnetic hyperthermia studies on high susceptible Fe1-xMgxFe2O4 superparamagnetic nanospheres

NASA Astrophysics Data System (ADS)

Manohar, A.; Krishnamoorthi, C.

2017-12-01

Majority studies on magnetic hyperthermia properties were carried out by modifying the saturation mass magnetization (Ms) of the samples. Here efforts were made to enhance the specific heat generation rate (SHGR) of single domain superparamagnetic (SP) material by modifying its magnetic susceptibility. Well crystallined, inverse spinel structured and close to monosize Fe1-xMgxFe2O4 (x = 0, 0.1, 0.2, 0.3, 0.4, & 0.5) compounds with nanosphere geometry (diameter 10 nm) were synthesized by solvothermal reflux method at ≈ 300 °C . In the literature it is reported that magnesium ferrites synthesized at high temperatures yield mixed (normal & inverse) spinel structures. The inverse spinel structure was confirmed by X-ray powder diffraction (XRPD), lattice vibrations and magnetic characteristics of the compounds. The Ms of the compounds decrease with increase of substituent Mg2+ concentration. Under high excitation energy the inter-valance charge transfer whereas under low excitation energy the intra-valance charge transfer process were predominant. The as-synthesized nanospheres were encapsulated by hydrophobic oleic acid and were exchanged by hydrophilic poly(acrylic acid) by chemical exchange process. Estimated magnetic hyperthermia power or SHGR of the x = 0, 0.3 & 0.5 were 11, 11.4 & 22.4 W per gram of respective compounds, respectively, under 63.4 kA m-1 field amplitude and 126 kHz frequency. The SHGR enhances with Mg2+ concentration though its Ms reduces and is attributed to reduced spin-orbital coupling in the compounds with enhanced Mg2+ concentration. This may pave a new way to develop magnetic hyperthermia material by modifying magnetic susceptibility of the compounds against to the reported Ms modification approach. The obtained high SHGR of the biocompatible compounds could be used in magnetic hyperthermia applications in biomedical field.

The Chemical Vapor Deposition of Thin Metal Oxide Films

NASA Astrophysics Data System (ADS)

Laurie, Angus Buchanan

1990-01-01

Chemical vapor deposition (CVD) is an important method of preparing thin films of materials. Copper (II) oxide is an important p-type semiconductor and a major component of high T_{rm c} superconducting oxides. By using a volatile copper (II) chelate precursor, copper (II) bishexafluoroacetylacetonate, it has been possible to prepare thin films of copper (II) oxide by low temperature normal pressure metalorganic chemical vapor deposition. In the metalorganic CVD (MOCVD) production of oxide thin films, oxygen gas saturated with water vapor has been used mainly to reduce residual carbon and fluorine content. This research has investigated the influence of water-saturated oxygen on the morphology of thin films of CuO produced by low temperature chemical vapor deposition onto quartz, magnesium oxide and cubic zirconia substrates. ZnO is a useful n-type semiconductor material and is commonly prepared by the MOCVD method using organometallic precursors such as dimethyl or diethylzinc. These compounds are difficult to handle under atmospheric conditions. In this research, thin polycrystalline films of zinc oxide were grown on a variety of substrates by normal pressure CVD using a zinc chelate complex with zinc(II) bishexafluoroacetylacetonate dihydrate (Zn(hfa)_2.2H _2O) as the zinc source. Zn(hfa) _2.2H_2O is not moisture - or air-sensitive and is thus more easily handled. By operating under reduced-pressure conditions (20-500 torr) it is possible to substantially reduce deposition times and improve film quality. This research has investigated the reduced-pressure CVD of thin films of CuO and ZnO. Sub-micron films of tin(IV) oxide (SnO _2) have been grown by normal pressure CVD on quartz substrates by using tetraphenyltin (TPT) as the source of tin. All CVD films were characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA).

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

Uemura, Kazuhiro, E-mail: k_uemura@gifu-u.ac.j; Onishi, Fumiaki; Yamasaki, Yukari

NO{sub 2} containing dicarboxylate bridging ligands, nitroterephthalate (bdc-NO{sub 2}) and 2,5-dinitroterephthalate (bdc-(NO{sub 2}){sub 2}), afford porous coordination polymers, {l_brace}[Zn{sub 2}(bdc-NO{sub 2}){sub 2}(dabco)].solvents{r_brace}{sub n} (2 contains solvents) and {l_brace}[Zn{sub 2}(bdc-(NO{sub 2}){sub 2}){sub 2}(dabco)].solvents{r_brace}{sub n} (3 contains solvents). Both compounds form jungle-gym-type regularities, where a 2D square grid composed of dinuclear Zn{sub 2} units and dicarboxylate ligands is bridged by dabco molecules to extend the 2D layers into a 3D structure. In 2 contains solvents and 3 contains solvents, a rectangle pore surrounded by eight Zn{sub 2} corners contains two and four NO{sub 2} moieties, respectively. Thermal gravimetry (TG) and X-ray powdermore » diffraction (XRPD) measurements reveal that both compounds maintain the frameworks regularities without guest molecules and with solvents such as MeOH, EtOH, i-PrOH, and Me{sub 2}CO. Adsorption measurements reveal that dried 2 and 3 adsorb H{sub 2}O molecules to be {l_brace}[Zn{sub 2}(bdc-NO{sub 2}){sub 2}(dabco)].4H{sub 2}O{r_brace}{sub n} (2 contains 4H{sub 2}O) and {l_brace}[Zn{sub 2}(bdc-(NO{sub 2}){sub 2}){sub 2}(dabco)].6H{sub 2}O{r_brace}{sub n} (3 contains 6H{sub 2}O), showing the pore hydrophilicity enhancement caused by NO{sub 2} group introduction. - Graphical abstract: Two hydrophilic porous coordination polymers, [Zn{sub 2}(bdc-NO{sub 2}){sub 2}(dabco)]{sub n} (2, bdc-NO{sub 2}=nitroterephthalate, dabco=1,4-diazabicyclo[2.2.2]octane) and [Zn{sub 2}(bdc-(NO{sub 2}){sub 2}){sub 2}(dabco)]{sub n} (3, bdc-(NO{sub 2}){sub 2}=2,5-dinitroterephthalate), have been synthesized and characterized by single X-ray analyses, thermal gravimetry, and adsorption measurements.« less

A multi-dataset data-collection strategy produces better diffraction data

PubMed Central

Liu, Zhi-Jie; Chen, Lirong; Wu, Dong; Ding, Wei; Zhang, Hua; Zhou, Weihong; Fu, Zheng-Qing; Wang, Bi-Cheng

2011-01-01

A multi-dataset (MDS) data-collection strategy is proposed and analyzed for macromolecular crystal diffraction data acquisition. The theoretical analysis indicated that the MDS strategy can reduce the standard deviation (background noise) of diffraction data compared with the commonly used single-dataset strategy for a fixed X-ray dose. In order to validate the hypothesis experimentally, a data-quality evaluation process, termed a readiness test of the X-ray data-collection system, was developed. The anomalous signals of sulfur atoms in zinc-free insulin crystals were used as the probe to differentiate the quality of data collected using different data-collection strategies. The data-collection results using home-laboratory-based rotating-anode X-ray and synchrotron X-ray systems indicate that the diffraction data collected with the MDS strategy contain more accurate anomalous signals from sulfur atoms than the data collected with a regular data-collection strategy. In addition, the MDS strategy offered more advantages with respect to radiation-damage-sensitive crystals and better usage of rotating-anode as well as synchrotron X-rays. PMID:22011470

Experimental determination of spin-dependent electron density by joint refinement of X-ray and polarized neutron diffraction data.

PubMed

Deutsch, Maxime; Claiser, Nicolas; Pillet, Sébastien; Chumakov, Yurii; Becker, Pierre; Gillet, Jean Michel; Gillon, Béatrice; Lecomte, Claude; Souhassou, Mohamed

2012-11-01

New crystallographic tools were developed to access a more precise description of the spin-dependent electron density of magnetic crystals. The method combines experimental information coming from high-resolution X-ray diffraction (XRD) and polarized neutron diffraction (PND) in a unified model. A new algorithm that allows for a simultaneous refinement of the charge- and spin-density parameters against XRD and PND data is described. The resulting software MOLLYNX is based on the well known Hansen-Coppens multipolar model, and makes it possible to differentiate the electron spins. This algorithm is validated and demonstrated with a molecular crystal formed by a bimetallic chain, MnCu(pba)(H(2)O)(3)·2H(2)O, for which XRD and PND data are available. The joint refinement provides a more detailed description of the spin density than the refinement from PND data alone.

Effect of variable parboiling on crystallinity of rice samples.

USDA-ARS?s Scientific Manuscript database

Rice parboiled at various combinations of cooking time and temperature, were analyzed by differential scanning calorimetry and X-Ray diffraction. Generally, gelatinization enthalpy decreased as the soaking temperature increased from 30ºC through 50ºC, and 70ºC to 90ºC, and gelatinization enthalpy d...

Synthesis and characterization of vanadiumoxidecatalysts supported on copper orthophosphates

NASA Astrophysics Data System (ADS)

Ouchabi, M.; Baalala, M.; Elaissi, A.; Loulidi, I.; Bensitel, M.

2017-03-01

Synthesis of a pure copper orthophosphate (CuP) prepared by Coprecipitation, and CuP modified by impregnation of vanadium (2-12 wt % of V2O5) have been carried out. The solids obtained were investigated as synthesized or after calcination by various physico-chemical techniques such as X-Ray Diffraction (XRD), Infrared Spectroscopy (IR), Thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The results revealed that the solids V/CuP consisted of copper orthophosphate Cu3(PO4)2 as major phases, together with V2O5 as minor phase. The diffraction lines of V2O5 increase by increasing the vanadium content.

Photoelectrochemical fabrication of spectroscopic diffraction gratings, phase 2

NASA Technical Reports Server (NTRS)

Rauh, R. David; Carrabba, Michael M.; Li, Jianguo; Cartland, Robert F.; Hachey, John P.; Mathew, Sam

1990-01-01

This program was directed toward the production of Echelle diffraction gratings by a light-driven, electrochemical etching technique (photoelectrochemical etching). Etching is carried out in single crystal materials, and the differential rate of etching of the different crystallographic planes used to define the groove profiles. Etching of V-groove profiles was first discovered by us during the first phase of this project, which was initially conceived as a general exploration of photoelectrochemical etching techniques for grating fabrication. This highly controllable V-groove etching process was considered to be of high significance for producing low pitch Echelles, and provided the basis for a more extensive Phase 2 investigation.

Instrument and method for focusing x rays, gamma rays, and neutrons

DOEpatents

Smither, R.K.

1981-04-20

A crystal diffraction instrument is described which has an improved crystalline structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg angle and thereby increasing the usable area and acceptance angle. The increased planar spacing is provided by the use of a temperature differential across the crystalline structure, by assembling a plurality of crystalline structure with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques.

Mechanochemical synthesis and structural characterization of three novel cocrystals of dimethylglyoxime with N-heterocyclic aromatic compounds and acetamide

NASA Astrophysics Data System (ADS)

Abidi, Syed Sibte Asghar; Azim, Yasser; Gupta, Abhishek Kumar; Pradeep, Chullikkattil P.

2017-12-01

With an aim to explore the interactions of (RR'Cdbnd Nsbnd OH) oxime moiety of dimethylglyoxime (DMG) with pyridyl ring of N-heterocyclic aromatic compounds and acetamide, three novel cocrystals of dimethylglyoxime with acridine (ACR), 1,10-phenanthroline monohydrate (PT) and acetamide (ACT) are reported. These three cocrystals were obtained with a mechanochemical synthesis approach and were characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), fourier transform-infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Additionally, Hirshfeld surface analysis is used to investigate the intermolecular interaction and the crystal packing of cocrystals.

Robust diffraction correction method for high-frequency ultrasonic tissue characterization

NASA Astrophysics Data System (ADS)

Raju, Balasundar

2004-05-01

The computation of quantitative ultrasonic parameters such as the attenuation or backscatter coefficient requires compensation for diffraction effects. In this work a simple and accurate diffraction correction method for skin characterization requiring only a single focal zone is developed. The advantage of this method is that the transducer need not be mechanically repositioned to collect data from several focal zones, thereby reducing the time of imaging and preventing motion artifacts. Data were first collected under controlled conditions from skin of volunteers using a high-frequency system (center frequency=33 MHz, BW=28 MHz) at 19 focal zones through axial translation. Using these data, mean backscatter power spectra were computed as a function of the distance between the transducer and the tissue, which then served as empirical diffraction correction curves for subsequent data. The method was demonstrated on patients patch-tested for contact dermatitis. The computed attenuation coefficient slope was significantly (p<0.05) lower at the affected site (0.13+/-0.02 dB/mm/MHz) compared to nearby normal skin (0.2+/-0.05 dB/mm/MHz). The mean backscatter level was also significantly lower at the affected site (6.7+/-2.1 in arbitrary units) compared to normal skin (11.3+/-3.2). These results show diffraction corrected ultrasonic parameters can differentiate normal from affected skin tissues.

Diffraction-controlled backscattering threshold and application to Raman gap

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

Rose, Harvey A.; Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544; Mounaix, Philippe

2011-04-15

In most classic analytical models of linear stimulated scatter, light diffraction is omitted, a priori. However, modern laser optic typically includes a variant of the random phase plate [Y. Kato et al., Phys. Rev. Lett. 53, 1057 (1984)], resulting in diffraction limited laser intensity fluctuations - or localized speckles - which may result in explosive reflectivity growth as the average laser intensity approaches a critical value [H. A. Rose and D. F. DuBois, Phys. Rev. Lett. 72, 2883 (1994)]. Among the differences between stimulated Raman scatter (SRS) and stimulated Brillouin scatter is that the SRS scattered light diffracts more stronglymore » than the laser light with increase of electron density. This weakens the tendency of the SRS light to closely follow the most amplified paths, diminishing gain. Let G{sub 0} be the one-dimensional power gain exponent of the stimulated scatter. In this paper we show that differential diffraction gives rise to an increase of G{sub 0} at the SRS physical threshold with increase of electron density up to a drastic disruption of SRS as electron density approaches one fourth of its critical value from below. For three wave interaction lengths not small compared to a speckle length, this is a physically robust Raman gap mechanism.« less

Solution combustion synthesis and characterization of nanosized bismuth ferrite

NASA Astrophysics Data System (ADS)

Sai Kumar, V. Sesha; Rao, K. Venkateswara; Krishnaveni, T.; Kishore Goud, A. Shiva; Reddy, P. Ranjith

2012-06-01

The present paper describes a simple method of nanosized BiFeO3 by the solution combustion synthesis using bismuth and iron nitrates as oxidizers and the combination fuel of citric acid and ammonium hydroxide, with fuel to oxidizer ratio (Ψ = 1) one. The X-ray Diffraction results indicated rhombohedral phase (R3m) with JCPDS data card no: 72-2035. The ferroelectric transition of the sample at 8310C was detected by differential thermal analysis. Thermal analysis was done by Thermal gravimetric-Differential thermal analyzer and obtained results were presented in this paper.

Reconstruction of Vertical Profile of Permittivity of Layered Media which is Probed Using Vertical Differential Antenna

NASA Astrophysics Data System (ADS)

Pochanin, Gennadiy P.; Poyedinchuk, Anatoliy Y.; Varianytsia-Roshchupkina, Liudmyla A.; Pochanina, Iryna Ye.

2016-04-01

Results of this research are intended to use at GPR investigations of layered media (for example, at roads' inspection) for the processing of collected data and reconstruction of dependence of permittivity on the depth. Recently, an antenna system with a vertical differential configuration of receiving module (Patent UA81652) for GPR was suggested and developed The main advantage of the differential antennas in comparison with bistatic antennas is a high electromagnetic decoupling between the transmitting and receiving modules. The new vertical differential configuration has an additional advantage because it allows collecting GPR data reflected by layered media without any losses of information about these layers [1] and, potentially, it is a more accurate instrument for the layers thickness measurements [2]. The developed antenna system is tested in practice with the GPR at asphalt thickness measurements [3] and shown an accuracy which is better than 0.5 cm. Since this antenna system is good for sounding from above the surface (air coupled technique), the mobile laboratory was equipped with the developed GPR [3]. In order to process big set of GPR data that collected during probing at long routes of the roads, for the data processing it was tested new algorithm of the inverse problem solution. It uses a fast algorithm for calculation of electromagnetic wave diffraction by non-uniform anisotropic layers [4]. The algorithm is based on constructing a special case solution to the Riccati equation for the Cauchy problem and enables a qualitative description of the wave diffraction by the electromagnetic structure of the type within a unitary framework. At this stage as initial data we used synthetic GPR data that were obtained as results of the FDTD simulation of the problem of UWB electromagnetic impulse diffraction on layered media. Differential and bistatic antenna configurations were tested at several different profiles of permittivity. Meanings of permittivity of each of layers were reconstructed successfully. Corresponding results are given in the presentation. Acknowledgement The authors acknowledge COST for funding Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar", supporting this work. References 1. L. Gurel, and U. Oguz, "Three-Dimensional FDTD modeling of a ground penetrating radar" IEEE Trans. Geosci. Remote Sensing, vol. 38, no. 4, pp. 1513-1521, 2000. 2. L. Varianytsia-Roshchupkina, Pochanin G., Pochanina I., Masalov Proc. of the 8th Int. Workshop on Advanced Ground Penetrating Radar (IWAGPR 15), Florence, Italy, July 2015. 3. Pochanin, G. P., Ruban, V. P., Kholod, P. V., Shuba, A. A., Pochanin, A. G., Orlenko, A.A., Batrakov, D. O., and Batrakova, A. G. GPR for pavement monitoring., Journal of Radio Electronics. No.1. 2013, Moscow, http://jre.cplire.ru/alt/jan13/8/text.pdf. 4. A. V. Brovenko, P. N. Melezhik, A. Y. Poyedinchuk A numerical analytical method for solving problems of electromagnetic wave diffraction by non-uniform anisotropic layers. Radiophysics and Electronics, Vol.19, No. 4. 2014. pp.12-20.

Chrysotile asbestos quantification in serpentinite quarries: a case study in Valmalenco, central Alps, northern Italy

NASA Astrophysics Data System (ADS)

Cavallo, Alessandro

2013-04-01

Outcrops of serpentinites are usually strongly fractured and cataclastic, and the rock can only be used as ballast. However, in rare cases, like in Valmalenco (Central Alps, Northern Italy), fractures are regular and well spaced, and the rock mass has good geotechnical quality, ideal conditions for the extraction of dimension stone blocks. The Valmalenco Serpentinite is marketed worldwide as dimension and decorative stone, with remarkable mechanical properties and pleasing colours and textures. However, the same area was once subject to chrysotile asbestos mining, in the form of discrete veins along the main discontinuities of the rock mass. For this reason, airborne asbestos contamination can occur during the extraction and processing cycle of the rocks, therefore it is essential to locate and quantify asbestos in the rock mass, to reduce as much as possible the exposure risk. The first step was a detailed geostructural survey of each quarry, in order to characterize the main discontinuities (orientation, spacing, linear persistence, opening, filling), with special attention to the identification of fibrous minerals. The surveys was followed by extensive sampling of massive rocks, mineralized veins and fillings of fractures, and the cutting sludge derived from diamond wire cutting. Preliminary qualitative XRPD was performed on all samples, while quantitative analysis was carried out on the most representative samples of the main rock mass discontinuities. On the other hand, XRPD is not effective in the identification of asbestos percentages of less than 2% by weight, and the accurate distinction among the various serpentine polymorphs (antigorite, lizardite, chrysotile) is very difficult (if not impossible) when they are simultaneously present, due to their very similar basic structure and the strong structural disorder. The same samples were then analyzed by SEM-EDS (fiber counting after filtration on a polycarbonate filter), for a better distinction between fibrous and lamellar polymorphs. A lot of minerals were identified in the mineralized veins: chrysotile, carbonates, talc, forsterite, brucite, chlorite, garnet (andradite), magnetite and sulphides. The quantitative XRPD and SEM-EDS analyses proved chrysotile percentages comprised between 11 and 100% by weight. On the other hand, chrysotile was never detected in the commercial massive rock. Considering the geostructural properties of the rock mass, the total asbestos content of the quarries is comprised between 0.23% and 0.02% by weight, very low percentages of no mining interest, classifiable as naturally occurring asbestos (NOA) occurrence. The SEM-EDS analyses also showed a slight chrysotile contamination close to the salvages of mineralized veins (in the form of chrysotile filled micro-fractures), for a thickness up to 5-6 cm. This study shows that the airborne asbestos exposure risk can be easily reduced by avoiding diamond wire or explosive cutting along the main mineralized veins, and by squaring off the blocks in the quarry (instead of processing plants). However, this study does not consider the possible asbestos occurrence in the form of micro-veins and micro-fractures, outside of the main discontinuities, and cannot be fully applied to highly fractured rock masses.

Physicochemical characterization of solid dispersions of carbamazepine formulated by supercritical carbon dioxide and conventional solvent evaporation method.

PubMed

Sethia, Sundeep; Squillante, Emilio

2002-09-01

Solid dispersions of carbamazepine (CBZ) were formulated by supercritical fluid processing (SCP) and conventional solvent evaporation in polyethylene glycol (PEG) 8000 with either Gelucire 44/14 or vitamin E TPGS NF (d-alpha-tocopheryl PEG 1000 succinate). Formulations were evaluated by dissolution, scanning electron microscopy, powder X-ray diffraction, and differential scanning calorimetry, and excipient cytotoxicity in Caco-2 cells by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay. CBZ release was enhanced from supercritical fluid-treated CBZ and the CBZ/PEG 8000 (1:5), CBZ/PEG 8000/TPGS or Gelucire 44/14 (1:4:1) solid dispersions. The radically altered morphologies of SCP samples seen by scanning electron microscopy suggested polymorphic change that was confirmed by the X-ray diffraction and differential scanning calorimetry. Disappearance of the characteristic CBZ melting peak indicated that CBZ was dissolved inside the carrier system. Polymorphic change of CBZ during SCP led to faster dissolution. Therefore, SCP provides advantages over solid dispersions prepared by conventional processes. Copyright 2002 Wiley-Liss Inc.

Air pollution levels reflected in deposits on building stone

NASA Astrophysics Data System (ADS)

Nord, Anders G.; Svärdh, Anna; Tronner, Kate

About 1400 samples of building stone have been collected in Sweden and other European countries, mainly from polluted areas but also from countryside districts. All samples have been analysed by SEM/EDS, and some selected by other techniques like XRPD, GC/MS, or ICP. In particular, we have determined concentrations of gypsum, iron and some other metals; chlorine, phosphorus, soot (carbon), and organic components. The results confirm a positive correlation between SO 2 concentrations and gypsum formation on calcareous stone. Polluted areas generate more metal particles and particles of soot, asphalt, car-tyre rubber, fly-ash, quartz, calcite, gypsum, and chlorides. On building façades in polluted cities about 100 constituents have been identified, including carcinogeneous organic compounds like benzopyrene.

Roman coloured and opaque glass: a chemical and spectroscopic study

NASA Astrophysics Data System (ADS)

Arletti, R.; Dalconi, M. C.; Quartieri, S.; Triscari, M.; Vezzalini, G.

2006-05-01

This work reports the results of an archaeometrical investigation of opaque Roman glass and is mainly focussed on the role of configuration and oxidation state of copper on the colour and opacity of red and green opaque finds (mosaic tesserae, game counters, and glass artefacts) from Sicily and Pompeii excavations. The glass fragments were characterised by EMPA, SEM-EDS, TEM, and XRPD analyses and the copper local environment was investigated using X-ray absorption spectroscopy. The analyses of high-resolution Cu-K edge XANES and EXAFS spectra suggest that, in red samples, copper is present as monovalent cations coordinated to the oxygen atoms of the glass framework, accompanied by metallic clusters. In green samples all the copper cations are incorporated in the glass matrix.

Pre-Columbian estucado pottery from El Salvador: A multi-technique investigation

NASA Astrophysics Data System (ADS)

Sodo, A.

2016-03-01

Pottery is one of the main productions of the pre-Columbian cultures in the Mesoamerican area. Among the others, the estucado pottery represents a very particular type of ceramic, widespread in Maya territory but still never investigated systematically. The peculiarity of this ceramic lies in the unusual application of the color decoration and in the excellent conservation conditions. Seventeen ceramic fragments from El Salvador have been analysed by Raman spectroscopy, SEM/EDS and XRPD, both as fragments and in cross-sections, in order to investigate the manufacturing technique and to understand the good and unexpected conservation state. In both cases, the presence and the chemical nature of a thin white layer (engobe) between the ceramic bulk and the colored decorations seems to be determinant.

Phase transitions of sodium niobate powder and ceramics, prepared by solid state synthesis

NASA Astrophysics Data System (ADS)

Koruza, J.; Tellier, J.; Malič, B.; Bobnar, V.; Kosec, M.

2010-12-01

Phase transitions of sodium niobate, prepared by the solid state synthesis method, were examined using dielectric measurements, differential scanning calorimetry, and high temperature x-ray diffraction, in order to contribute to the clarification of its structural behavior below 400 °C. Four phase transitions were detected in the ceramic sample using dielectric measurements and differential scanning calorimetry and the obtained temperatures were in a good agreement with previous reports for the transitions of the P polymorph. The anomaly observed by dielectric measurements in the vicinity of 150 °C was frequency dependent and could be related to the dynamics of the ferroelectric nanoregions. The phase transitions of the as-synthesized NaNbO3 powder were investigated using differential scanning calorimetry and high temperature x-ray diffraction. The results show the existence of the Q polymorph at room temperature, not previously reported for the powder, which undergoes a transition to the R polymorph upon heating through a temperature region between 265 and 326.5 °C. This transition is mainly related to the displacement of Na into a more symmetric position and a minor change in the tilting system. The structures at room temperature, 250, 300, and 420 °C were refined by the Rietveld method and the evolution of the tilting system of the octahedral network and cationic displacement are reported.

Extreme mechanical properties of materials under extreme pressure and temperature conditions (Invited)

NASA Astrophysics Data System (ADS)

Kavner, A.; Armentrout, M. M.; Xie, M.; Weinberger, M.; Kaner, R. B.; Tolbert, S. H.

2010-12-01

A strong synergy ties together the high-pressure subfields of mineral physics, solid-state physics, and materials engineering. The catalog of studies measuring the mechanical properties of materials subjected to large differential stresses in the diamond anvil cell demonstrates a significant pressure-enhancement of strength across many classes of materials, including elemental solids, salts, oxides, silicates, and borides and nitrides. High pressure techniques—both radial diffraction and laser heating in the diamond anvil cell—can be used to characterize the behavior of ultrahard materials under extreme conditions, and help test hypotheses about how composition, structure, and bonding work together to govern the mechanical properties of materials. The principles that are elucidated by these studies can then be used to help design engineering materials to encourage desired properties. Understanding Earth and planetary interiors requires measuring equations of state of relevant materials, including oxides, silicates, and metals under extreme conditions. If these minerals in the diamond anvil cell have any ability to support a differential stress, the assumption of quasi-hydrostaticity no longer applies, with a resulting non-salubrious effect on attempts to measure equation of state. We illustrate these applications with the results of variety of studies from our laboratory and others’ that have used high-pressure radial diffraction techniques and also laser heating in the diamond anvil cell to characterize the mechanical properties of a variety of ultrahard materials, especially osmium metal, osmium diboride, rhenium diboride, and tungsten tetraboride. We compare ambient condition strength studies such as hardness testing with high-pressure studies, especially radial diffraction under differential stress. In addition, we outline criteria for evaluating mechanical properties of materials at combination high pressures and temperatures. Finally, we synthesize our understanding of mechanical properties and composite behavior to suggest new approaches to designing high-pressure experiments to target specific measurements of a wide variety of mechanical properties.

Transmission in situ and operando high temperature X-ray powder diffraction in variable gaseous environments

NASA Astrophysics Data System (ADS)

Schlicker, Lukas; Doran, Andrew; Schneppmüller, Peter; Gili, Albert; Czasny, Mathias; Penner, Simon; Gurlo, Aleksander

2018-03-01

This work describes a device for time-resolved synchrotron-based in situ and operando X-ray powder diffraction measurements at elevated temperatures under controllable gaseous environments. The respective gaseous sample environment is realized via a gas-tight capillary-in-capillary design, where the gas flow is achieved through an open-end 0.5 mm capillary located inside a 0.7 mm capillary filled with a sample powder. Thermal mass flow controllers provide appropriate gas flows and computer-controlled on-the-fly gas mixing capabilities. The capillary system is centered inside an infrared heated, proportional integral differential-controlled capillary furnace allowing access to temperatures up to 1000 °C.

Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography.

PubMed

Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

2016-01-01

The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach to the subject.

Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography

PubMed Central

Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

2016-01-01

The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach to the subject. PMID:26943121

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

In-situ synchrotron wide-angle X-ray diffraction as a rapid method for cocrystal/salt screening.

PubMed

Dong, Pin; Lin, Ling; Li, Yongcheng; Huang, Zhengwei; Lang, Tianqun; Wu, Chuanbin; Lu, Ming

2015-12-30

The purpose of this work was to explore in-situ synchrotron wide-angle X-ray diffraction (WAXD) as a rapid and accurate tool to screen and monitor the formation of cocrystal/salts during heating. The active pharmaceutical ingredients (caffeine, carbamazepine and lamotrigine) were respectively mixed with the coformer (saccharin), and then heated by the hot stage. Real-time process monitoring was performed using synchrotron WAXD to assess cocrystal formation and subsequently compared to differential scanning calorimetry (DSC) measurements. The effect of heating rates and cocrystal growth behavior were investigated. Synchrotron WAXD was fast and sensitive to detect cocrystal formation with the appearance of characteristic diffraction rings, even at the heating rate of 30°C/min, while DSC curves showed overlapped peaks. Unlike the indirect characterization of DSC on endo/exothermic peaks, synchrotron WAXD can directly and qualitatively determine cocrystal by diffraction peaks. The diffraction intensity-temperature curves and the corresponding first-derivative curves clearly exhibited the growth behavior of cocrystal upon heating, providing useful information to optimize the process temperature of hot melt extrusion to continuously manufacture cocrystal. The study suggests that in-situ synchrotron WAXD could provide a one-step process to screen cocrystal at high efficiency and reveal the details of cocrystal/salts growth behavior. Copyright © 2015 Elsevier B.V. All rights reserved.

Color fluctuations in hadrons and proton coherent diffractive dissociation on helium

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

Strikman, M.; Guzey, V.

The differential cross section of inelastic coherent diffractive dissociation off nuclei {ital p}+{sup 4}He {r_arrow}{ital X}+{sup 4}He is expressed in terms of the relative cumulants of the cross-section distribution {ital P}{sub {ital N}}({sigma}). The theoretical result for the ratio {ital r}=({ital d}{sigma}{sub diff}/{ital dt}){sub {ital t}=0}{sup {ital p}He}/({ital d}{sigma}{sub diff}/{ital dt}) {sub {ital t}=0}{sup {ital pp}}=6.8--7.6 is close to the value {ital r}=7.1{plus_minus}0.7 which we extracted from the FNAL data. These are the only {ital A}{gt}2 data of this kind. The comparison provides the first confirmation of the color/cross-section fluctuation approach to the description of the absolute value of themore » inelastic diffraction cross section off nuclei. It provides also a new constraint on the first four cumulants of the cross-section distribution.« less

Structures and phase transitions in a new ferroelectric -- pyridinium chlorochromate -- studied by X-ray diffraction, DSC and dielectric methods.

PubMed

Małuszyńska, Hanna; Czarnecki, Piotr; Czarnecka, Anna; Pająk, Zdzisław

2012-04-01

Pyridinium chlorochromate, [C(5)H(5)NH](+)[ClCrO(3)](-) (hereafter referred to as PyClCrO(3)), was studied by X-ray diffraction, differential scanning calorimetry (DSC) and dielectric methods. Studies reveal three reversible phase transitions at 346, 316 and 170 K with the following phase sequence: R ̅3m (I) → R3m (II) → Cm (III) → Cc (IV), c' = 2c. PyClCrO(3) is the first pyridinium salt in which all four phases have been successfully characterized by a single-crystal X-ray diffraction method. Structural results together with dielectric and calorimetric studies allow the classification of the two intermediate phases (II) and (III) as ferroelectric with the Curie point at 346 K, and the lowest phase (IV) as most probably ferroelectric. The ferroelectric hysteresis loop was observed only in phase (III). The high ionic conductivity hindered its observation in phase (II).

Tropical sea snail shells: Possible exotic sources for ceramic biomaterial synthesis

NASA Astrophysics Data System (ADS)

Oktar, F. N.; Kiyici, I. A.; Gökçe, H.; Aǧaogulları, D.; Kayali, E. S.

2013-12-01

In this study, chemical and structural properties of sea snail shell based bioceramic materials (i.e. hydroxyapatite, whitlockite and other phases) are produced by using mechano-chemical (ultrasonic) conversion method. For this purpose, differential thermal and gravimetric analysis (DTA/TG), X-ray diffraction, infra-red (IR) and scanning electron microscope (SEM) studies are performed.

Influence of solvents on the habit modification of alpha lactose monohydrate single crystals

NASA Astrophysics Data System (ADS)

Parimaladevi, P.; Srinivasan, K.

2013-02-01

Restricted evaporation of solvent method was adopted for the growth of alpha lactose monohydrate single crystals from different solvents. The crystal habits of grown crystals were analysed. The form of crystallization was confirmed by powder x-ray diffraction analysis. Thermal behaviour of the grown crystals was studied by using differential scanning calorimetry.

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.

Hot Melt Extrusion: Development of an Amorphous Solid Dispersion for an Insoluble Drug from Mini-scale to Clinical Scale.

PubMed

Agrawal, Anjali M; Dudhedia, Mayur S; Zimny, Ewa

2016-02-01

The objective of the study was to develop an amorphous solid dispersion (ASD) for an insoluble compound X by hot melt extrusion (HME) process. The focus was to identify material-sparing approaches to develop bioavailable and stable ASD including scale up of HME process using minimal drug. Mixtures of compound X and polymers with and without surfactants or pH modifiers were evaluated by hot stage microscopy (HSM), polarized light microscopy (PLM), and modulated differential scanning calorimetry (mDSC), which enabled systematic selection of ASD components. Formulation blends of compound X with PVP K12 and PVP VA64 polymers were extruded through a 9-mm twin screw mini-extruder. Physical characterization of extrudates by PLM, XRPD, and mDSC indicated formation of single-phase ASD's. Accelerated stability testing was performed that allowed rapid selection of stable ASD's and suitable packaging configurations. Dissolution testing by a discriminating two-step non-sink dissolution method showed 70-80% drug release from prototype ASD's, which was around twofold higher compared to crystalline tablet formulations. The in vivo pharmacokinetic study in dogs showed that bioavailability from ASD of compound X with PVP VA64 was four times higher compared to crystalline tablet formulations. The HME process was scaled up from lab scale to clinical scale using volumetric scale up approach and scale-independent-specific energy parameter. The present study demonstrated systematic development of ASD dosage form and scale up of HME process to clinical scale using minimal drug (∼500 g), which allowed successful clinical batch manufacture of enabled formulation within 7 months.

Hydroxyapatite grafted carbon nanotubes and graphene nanosheets: Promising bone implant materials

NASA Astrophysics Data System (ADS)

Oyefusi, Adebola; Olanipekun, Opeyemi; Neelgund, Gururaj M.; Peterson, Deforest; Stone, Julia M.; Williams, Ebonee; Carson, Laura; Regisford, Gloria; Oki, Aderemi

2014-11-01

In the present study, hydroxyapatite (HA) was successfully grafted to carboxylated carbon nanotubes (CNTs) and graphene nanosheets. The HA grafted CNTs and HA-graphene nanosheets were characterized using FT-IR, TGA, SEM and X-ray diffraction. The HA grafted CNTs and graphene nanosheets (CNTs-HA and Gr-HA) were further used to examine the proliferation and differentiation rate of temperature-sensitive human fetal osteoblastic cell line (hFOB 1.19). Total protein assays and western blot analysis of osteocalcin expression were used as indicators of cell proliferation and differentiation. Results indicated that hFOB 1.19 cells proliferate and differentiate well in treatment media containing CNTs-HA and graphene-HA. Both CNTs-HA and graphene-HA could be promising nanomaterials for use as scaffolds in bone tissue engineering.

Reaching the Diffraction Limit - Differential Speckle and Wide-Field Imaging for the WIYN Telescope

NASA Technical Reports Server (NTRS)

Scott, Nic J.; Howell, Steve; Horch, Elliott

2016-01-01

Speckle imaging allows telescopes to achieve diffraction limited imaging performance. The technique requires cameras capable of reading out frames at a very fast rate, effectively 'freezing out' atmospheric seeing. The resulting speckles can be correlated and images reconstructed that are at the diffraction limit of the telescope. These new instruments are based on the successful performance and design of the Differential Speckle Survey Instrument (DSSI).The instruments are being built for the Gemini-N and WIYN telescopes and will be made available to the community via the peer review proposal process. We envision their primary use to be validation and characterization of exoplanet targets from the NASA, K2 and TESS missions and RV discovered exoplanets. Such targets will provide excellent follow-up candidates for both the WIYN and Gemini telescopes. We expect similar data quality in speckle imaging mode with the new instruments. Additionally, both cameras will have a wide-field mode and standard SDSS filters. They will be highly versatile instruments and it is that likely many other science programs will request time on the cameras. The limiting magnitude for speckle observations will remain around 13-14th at WIYN and 16-17th at Gemini, while wide-field, normal CCD imaging operation should be able to go to much fainter, providing usual CCD imaging and photometric capabilities. The instruments will also have high utility as scoring cameras for telescope engineering purposes, or other applications where high time resolution is needed. Instrument support will be provided, including a software pipeline that takes raw speckle data to fully reconstructed images.

Preparation, crystallization and preliminary X-ray diffraction analysis of two intestinal fatty-acid binding proteins in the presence of 11-(dansylamino)undecanoic acid

PubMed Central

Laguerre, Aisha; Wielens, Jerome; Parker, Michael W.; Porter, Christopher J. H.; Scanlon, Martin J.

2011-01-01

Fatty-acid binding proteins (FABPs) are abundantly expressed proteins that bind a range of lipophilic molecules. They have been implicated in the import and intracellular distribution of their ligands and have been linked with metabolic and inflammatory responses in the cells in which they are expressed. Despite their high sequence identity, human intestinal FABP (hIFABP) and rat intestinal FABP (rIFABP) bind some ligands with different affinities. In order to address the structural basis of this differential binding, diffraction-quality crystals have been obtained of hIFABP and rIFABP in complex with the fluorescent fatty-acid analogue 11-(dansylamino)undecanoic acid. PMID:21301109

Evidence of monotropic hexatic tilted smectic phase in the phase sequence of ferroelectric liquid crystal

NASA Astrophysics Data System (ADS)

Różycka, Anna; Deptuch, Aleksandra; Jaworska-Gołąb, Teresa; Węgłowska, Dorota; Marzec, Monika

2018-02-01

Physical properties of a new ferroelectric liquid crystal have been studied by complementary methods: differential scanning calorimetry, polarizing optical microscopy, dielectric and X-ray diffraction. It was found that next to enantiotropic ferroelectric smectic C* phase, the monotropic smectic phase appears at cooling. X-ray diffraction measurements allowed to identify this phase as hexatic tilted smectic. Temperature dependence of spontaneous polarization, tilt angle of molecules and switching time were found in both liquid crystalline phases at cooling. Based on the dielectric results, the dielectric processes were identified as Goldstone mode in the smectic C* phase, whereas as the bond-orientation-like phason and the bulk domain mode in the monotropic hexatic tilted smectic phase.

Multifit / Polydefix : a framework for the analysis of polycrystal deformation using X-rays

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

Merkel, Sébastien; Hilairet, Nadège

2015-06-27

Multifit/Polydefixis an open source IDL software package for the efficient processing of diffraction data obtained in deformation apparatuses at synchrotron beamlines.Multifitallows users to decompose two-dimensional diffraction images into azimuthal slices, fit peak positions, shapes and intensities, and propagate the results to other azimuths and images.Polydefixis for analysis of deformation experiments. Starting from output files created inMultifitor other packages, it will extract elastic lattice strains, evaluate sample pressure and differential stress, and prepare input files for further texture analysis. TheMultifit/Polydefixpackage is designed to make the tedious data analysis of synchrotron-based plasticity, rheology or other time-dependent experiments very straightforward and accessible tomore » a wider community.« less

Elastic break-up of 156 MeV 6Li projectiles with large asymptotic relative momenta of the fragments: . Experimental observations and the diffractive disintegration approach

NASA Astrophysics Data System (ADS)

Heide, N.; Rebel, H.; Corcalciuc, V.; Gils, H. J.; Jelitto, H.; Kiener, J.; Wentz, J.; Zagromski, S.; Srivastava, D. K.

1989-11-01

The triple-differential cross sections for elastic break-up of 156 MeV 6Li projectiles by the reactions 208Pb( 6Li, αd) 208Pb g.s. and 12C( 6Li, αd) 12C g.s. have been measured with large asymptotic relative momenta of the outgoing fragments. The data exhibit rather unfamiliar shapes of the energy spectra, often replacing the usual bell-shape distributions by double-peaked structures and varying rapidly with the relative emission angles. The origin of these features has been explored and the cross sections have been analysed on the basis of a diffractive disintegration approach.

Fatigue crack propagation behavior of ultrahigh molecular weight polyethylene.

PubMed

Connelly, G M; Rimnac, C M; Wright, T M; Hertzberg, R W; Manson, J A

1984-01-01

The relative fatigue crack propagation resistance of plain and carbon fiber-reinforced ultrahigh molecular weight polyethylene (UHMWPE) was determined from cyclic loading tests performed on compact tension specimens machined from the tibial components of total knee prostheses. Both materials were characterized by dynamic mechanical spectroscopy, X-ray diffraction, and differential scanning calorimetry. The cyclic tests used loading in laboratory air at 5 Hz using a sinusoidal wave form. Dynamic mechanical spectroscopy showed that the reinforced UHMWPE had a higher elastic storage modulus than the plain UHMWPE, whereas X-ray diffraction and differential scanning calorimetry showed that the percent crystallinity and degree of order in the crystalline regions were similar for the two materials. Fatigue crack propagation in both materials proved to be very sensitive to small changes in the applied cyclic stress intensity range. A 10% increase in stress intensity resulted in approximately an order of magnitude increase in fatigue crack growth rate. The fatigue crack propagation resistance of the reinforced UHMWPE was found to be significantly worse than that of the plain UHMWPE. This result was attributed to poor bonding between the carbon fibers and the UHMWPE matrix and the ductile nature of the matrix itself.

Phase diagram and electrical behavior of silicon-rich iridium silicide compounds

NASA Technical Reports Server (NTRS)

Allevato, C. E.; Vining, Cronin B.

1992-01-01

The iridium-silicon phase diagram on the silicon-rich side was investigated by means of X-ray powder diffraction, density, differential thermal analysis, metalography, microprobe analysis, and electrical resistivity. Attempts were made to prepare eight previously reported silicon-rich iridium silicide compounds by arc melting and Bridgman-like growth. However, microprobe analysis identified only four distinct compositions: IrSi, Ir3Si4, Ir3Si5 and IrSi sub about 3. The existence of Ir4Si5 could not be confirmed in this study, even though the crystal structure has been previously reported. Differential thermal analysis (DTA) in conjunction with X-ray powder diffraction confirm polymorphism in IrSi sub about 3, determined to have orthorhombic and monoclinic unit cells in the high and low temperature forms. A eutectic composition alloy of 83 +/- 1 atomic percent silicon was observed between IrSi sub about 3 and silicon. Ir3Si4 exhibits distinct metallic behavior while Ir3Si5 is semiconducting. Both and IrSi and IrSi sub about 3 exhibit nearly temperature independent electrical resistivities on the order of 5-10 x 10 exp -6 ohms-m.

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.

Imaging ultrafast dynamics of molecules with laser-induced electron diffraction.

PubMed

Lin, C D; Xu, Junliang

2012-10-14

We introduce a laser-induced electron diffraction method (LIED) for imaging ultrafast dynamics of small molecules with femtosecond mid-infrared lasers. When molecules are placed in an intense laser field, both low- and high-energy photoelectrons are generated. According to quantitative rescattering (QRS) theory, high-energy electrons are produced by a rescattering process where electrons born at the early phase of the laser pulse are driven back to rescatter with the parent ion. From the high-energy electron momentum spectra, field-free elastic electron-ion scattering differential cross sections (DCS), or diffraction images, can be extracted. With mid-infrared lasers as the driving pulses, it is further shown that the DCS can be used to extract atomic positions in a molecule with sub-angstrom spatial resolution, in close analogy to the standard electron diffraction method. Since infrared lasers with pulse duration of a few to several tens of femtoseconds are already available, LIED can be used for imaging dynamics of molecules with sub-angstrom spatial and a few-femtosecond temporal resolution. The first experiment with LIED has shown that the bond length of oxygen molecules shortens by 0.1 Å in five femtoseconds after single ionization. The principle behind LIED and its future outlook as a tool for dynamic imaging of molecules are presented.

Local structure of In0.5Ga0.5As from joint high-resolution and differential pair distribution function analysis

NASA Astrophysics Data System (ADS)

Petkov, V.; Jeong, I.-K.; Mohiuddin-Jacobs, F.; Proffen, Th.; Billinge, S. J. L.; Dmowski, W.

2000-07-01

High resolution total and indium differential atomic pair distribution functions (PDFs) for In0.5Ga0.5As alloys have been obtained by high energy and anomalous x-ray diffraction experiments, respectively. The first peak in the total PDF is resolved as a doublet due to the presence of two distinct bond lengths, In-As and Ga-As. The In differential PDF, which involves only atomic pairs containing In, yields chemical specific information and helps ease the structure data interpretation. Both PDFs have been fit with structure models and the way in that the underlying cubic zinc-blende lattice of In0.5Ga0.5As semiconductor alloy distorts locally to accommodate the distinct In-As and Ga-As bond lengths present has been quantified.

Crystal growth of cholesterol in hydrogels and its characterization

NASA Astrophysics Data System (ADS)

Manuel Bravo-Arredondo, J.; Moreno, A.; Mendoza, M. E.

2014-09-01

In this work, we report the crystallization of cholesterol in ethanol solution and in three different hydrogel media: tetramethyl orthosilane, sodium metasilicate, and poly(vinyl)alcohol, whose structures are similar to the gel-like polymer structure of mucin, which is found in the mucus present in bile stone formation. The monohydrated triclinic phase was identified in all the samples by means of X-ray powder diffraction. The characteristic polymorphic crystalline transition of the anhydrous cholesterol was detected by differential thermal analysis and modulated differential scanning calorimetry only in crystals grown in ethanol, sodium silicate, and tetramethyl orthosilane. Finally, hysteresis of the phase transition temperature was measured by modulated differential scanning calorimetry in crystals grown in ethanol. The biological implications of the crystallization of cholesterol for bile stones formation are discussed in the last part of this contribution.

Hydroxyapatite grafted carbon nanotubes and graphene nanosheets: promising bone implant materials.

PubMed

Oyefusi, Adebola; Olanipekun, Opeyemi; Neelgund, Gururaj M; Peterson, Deforest; Stone, Julia M; Williams, Ebonee; Carson, Laura; Regisford, Gloria; Oki, Aderemi

2014-11-11

In the present study, hydroxyapatite (HA) was successfully grafted to carboxylated carbon nanotubes (CNTs) and graphene nanosheets. The HA grafted CNTs and HA-graphene nanosheets were characterized using FT-IR, TGA, SEM and X-ray diffraction. The HA grafted CNTs and graphene nanosheets (CNTs-HA and Gr-HA) were further used to examine the proliferation and differentiation rate of temperature-sensitive human fetal osteoblastic cell line (hFOB 1.19). Total protein assays and western blot analysis of osteocalcin expression were used as indicators of cell proliferation and differentiation. Results indicated that hFOB 1.19 cells proliferate and differentiate well in treatment media containing CNTs-HA and graphene-HA. Both CNTs-HA and graphene-HA could be promising nanomaterials for use as scaffolds in bone tissue engineering. Copyright © 2014 Elsevier B.V. All rights reserved.

Extracting conformational structure information of benzene molecules via laser-induced electron diffraction

DOE PAGES

Ito, Yuta; Wang, Chuncheng; Le, Anh-Thu; ...

2016-05-01

Here, we have measured the angular distributions of high energy photoelectrons of benzene molecules generated by intense infrared femtosecond laser pulses. These electrons arise from the elastic collisions between the benzene ions with the previously tunnel-ionized electrons that have been driven back by the laser field. Theory shows that laser-free elastic differential cross sections (DCSs) can be extracted from these photoelectrons, and the DCS can be used to retrieve the bond lengths of gas-phase molecules similar to the conventional electron diffraction method. From our experimental results, we have obtained the C-C and C-H bond lengths of benzene with a spatialmore » resolution of about 10 pm. Our results demonstrate that laser induced electron diffraction (LIED) experiments can be carried out with the present-day ultrafast intense lasers already. Looking ahead, with aligned or oriented molecules, more complete spatial information of the molecule can be obtained from LIED, and applying LIED to probe photo-excited molecules, a “molecular movie” of the dynamic system may be created with sub-A°ngstrom spatial and few-ten femtosecond temporal resolutions.« less

Clay pigment structure characterisation as a guide for provenance determination--a comparison between laboratory powder micro-XRD and synchrotron radiation XRD.

PubMed

Švarcová, Silvie; Bezdička, Petr; Hradil, David; Hradilová, Janka; Žižak, Ivo

2011-01-01

Application of X-ray diffraction (XRD)-based techniques in the analysis of painted artworks is not only beneficial for indisputable identification of crystal constituents in colour layers, but it can also bring insight in material crystal structure, which can be affected by their geological formation, manufacturing procedure or secondary changes. This knowledge might be helpful for art historic evaluation of an artwork as well as for its conservation. By way of example of kaolinite, we show that classification of its crystal structure order based on XRD data is useful for estimation of its provenance. We found kaolinite in the preparation layer of a Gothic wall painting in a Czech church situated near Karlovy Vary, where there are important kaolin deposits. Comparing reference kaolin materials from eight various Czech deposits, we found that these can be differentiated just according to the kaolinite crystallinity. Within this study, we compared laboratory powder X-ray micro-diffraction (micro-XRD) with synchrotron radiation X-ray diffraction analysing the same real sample. We found that both techniques led to the same results.

Type I and type II residual stress in iron meteorites determined by neutron diffraction measurements

NASA Astrophysics Data System (ADS)

Caporali, Stefano; Pratesi, Giovanni; Kabra, Saurabh; Grazzi, Francesco

2018-04-01

In this work we present a preliminary investigation by means of neutron diffraction experiment to determine the residual stress state in three different iron meteorites (Chinga, Sikhote Alin and Nantan). Because of the very peculiar microstructural characteristic of this class of samples, all the systematic effects related to the measuring procedure - such as crystallite size and composition - were taken into account and a clear differentiation in the statistical distribution of residual stress in coarse and fine grained meteorites were highlighted. Moreover, the residual stress state was statistically analysed in three orthogonal directions finding evidence of the existence of both type I and type II residual stress components. Finally, the application of von Mises approach allowed to determine the distribution of type II stress.

Preparation of Al-Ti Master Alloys by Aluminothermic Reduction of TiO2 in Cryolite Melts at 960°C

NASA Astrophysics Data System (ADS)

Liu, Aimin; Xie, Kaiyu; Li, Liangxing; Shi, Zhongning; Hu, Xianwei; Xu, Junli; Gao, Bingliang; Wang, Zhaowen

Al-Ti master alloys were prepared by aluminothermic reduction between the dissolved titanium dioxide and aluminum in cryolite melts at 960°C. The kinetic analysis by differential scanning calorimetry indicated that the apparent activation energy of the reaction of reducing titanium dioxide by aluminium is 22.3 kJ/mol, and the reaction order is 0.5. The products were analyzed by means of X-ray diffraction, X-ray fluorescence, scanning electron microscopy and energy dispersive spectrometer. Results from X-ray diffraction showed that the phase compositions of produced alloys are Al and Al3Ti. In addition, Al-Ti master alloys containing 2-6 mass% Ti were formed at different reduction time of 2-5h in aluminothermic reduction experiment.

Effect of differential speed rolling on the texture evolution of Mg-4Zn-1Gd alloy

NASA Astrophysics Data System (ADS)

Shim, Myeong-Shik; Suh, Byeong-Chan; Kim, Jae H.; Kim, Nack J.

2015-05-01

The microstructural and texture evolution during differential speed rolling process of Mg 4Zn-1Gd (wt%) alloy have been investigated by means of electron backscatter diffraction observation and texture analysis. The angular distribution of basal poles are inclined about 10° from the normal direction towards the rolling direction and the maximum intensities of basal poles are decreased, compared to the conventional rolling process. Such an inclination of angular distribution of basal poles can be induced by the operation of shear stress along the rolling direction, as much as one quarter of tensile stress along the RD and one quarter of compressive stress along the ND. When the reduction ratios in differential speed rolling increase, there is no difference in texture evolution although there is a significant change in activated twinning systems. In addition, the engineering stresses after differential speed rolling are also similar to that after conventional rolling process, while ductility and stretch formability in the former are worse than those in the latter.

Compositional and Microtextural Analysis of Basaltic Feedstock Materials Used for the 2010 ISRU Field Tests, Mauna Kea, Hawaii

NASA Astrophysics Data System (ADS)

Marin, N.; Farmer, J. D.; Zacny, K.; Sellar, R. G.; Nunez, J.

2011-12-01

This study seeks to understand variations in composition and texture of basaltic pyroclastic materials used in the 2010 International Lunar Surface Operation-In-Situ Resource Utilization Analogue Test (ILSO-ISRU) held on the slopes of Mauna Kea Volcano, Hawaii (1). The quantity and quality of resources delivered by ISRU depends upon the nature of the materials processed (2). We obtained a one-meter deep auger cuttings sample of a basaltic regolith at the primary site for feed stock materials being mined for the ISRU field test. The auger sample was subdivided into six, ~16 cm depth increments and each interval was sampled and characterized in the field using the Multispectral Microscopic Imager (MMI; 3) and a portable X-ray Diffractometer (Terra, InXitu Instruments, Inc.). Splits from each sampled interval were returned to the lab and analyzed using more definitive methods, including high resolution Powder X-ray Diffraction and Thermal Infrared (TIR) spectroscopy. The mineralogy and microtexture (grain size, sorting, roundness and sphericity) of the auger samples were determined using petrographic point count measurements obtained from grain-mount thin sections. NIH Image J (http://rsb.info.nih.gov/ij/) was applied to digital images of thin sections to document changes in particle size with depth. Results from TIR showed a general predominance of volcanic glass, along with plagioclase, olivine, and clinopyroxene. In addition, thin section and XRPD analyses showed a down core increase in the abundance of hydrated iron oxides (as in situ weathering products). Quantitative point count analyses confirmed the abundance of volcanic glass in samples, but also revealed olivine and pyroxene to be minor components, that decreased in abundance with depth. Furthermore, point count and XRD analyses showed a decrease in magnetite and ilmenite with depth, accompanied by an increase in Fe3+phases, including hematite and ferrihydrite. Image J particle analysis showed that the average grain size decreased down the depth profile. This decrease in average grain size and increase in hydrated iron oxides down hole suggests that the most favorable ISRU feedstock materials were sampled in the lower half-meter of the mine section sampled.

Electrocatalytic properties of three new POMs-based inorganic–organic frameworks with flexible zwitterionic dicarboxylate ligands

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

Ren, Yanli; Li, Ling; Mu, Bao

2017-05-15

Three POMs–based inorganic–organic frameworks, namely, [Cu{sub 2}(L){sub 2}(SiW{sub 12}O{sub 40})(H{sub 2}O){sub 2}]·6H{sub 2}O (1), [Co{sub 2}(L){sub 2}(SiW{sub 12}O{sub 40})(H{sub 2}O){sub 8}]·8H{sub 2}O (2) and [Ni{sub 2}(L){sub 2}(SiW{sub 12}O{sub 40})(H{sub 2}O){sub 8}]·6H{sub 2}O (3), (L=1,1′-(1,4-phenylene-bis(methylene))-bis(pyridine-3-carboxylic acid)), have been synthesized and characterized by elemental analyses, IR, XRPD, TG, and single crystal X-ray diffraction. Compound 1 contains 1D double chains decorated by (Cu{sub 2}(L){sub 4}(H{sub 2}O){sub 2}) units and the 1D chains and POMs are stacked to yield 2D frameworks. Compound 2 displays a 2D network constructed from 1D zigzag chains and POMs arranged in ABAB mode. Compound 3 consists of big squaremore » girds and the POMs are dispersed in the middle of the two adjacent girds, forming 2D networks. Compounds 1–3 all show structural integrity in aqueous solutions at different pH values and in common organic solvents. Additionally, the fluorescence and electrochemical properties of compounds 1–3 are also investigated. Compounds 1–3 exhibit good electrocatalytic activities for the reduction of NaNO{sub 2} and H{sub 2}O{sub 2}. - Highlights: • Compound 1–3 all contain different 1D chains. The noncovalent interaction of metal–organic moieties from compounds 1–3 and POMs to construct three new host–guest supramolecular compounds. • Compounds 1–3 show good electrocatalytic activities towards the reduction of NaNO{sub 2} and H{sub 2}O{sub 2}. • Compounds 1–3 all show structural integrity in aqueous solutions at different pH values and in common organic solvents. • Compounds 1–3 may be promising luminescent materials due to their luminescent properties.« less

Measurement of diffraction dissociation cross sections in pp collisions at $$\\sqrt{s}$$ = 7 TeV

DOE PAGES

Khachatryan, Vardan

2015-07-06

Measurements of diffractive dissociation cross sections in pp collisions at √s=7 TeV are presented in kinematic regions defined by the masses M X and M Y of the two final-state hadronic systems separated by the largest rapidity gap in the event. The differential cross sections are measured as a function of ξ X = M2 X /s in the region -5.5 < log 10ξ X < -2.5, for log 10M Y < 0.5, dominated by single dissociation (SD), and 0.5 < log10M Y < 1.1, dominated by double dissociation (DD), where M X and M Y are given in GeV.more » The inclusive pp cross section is also measured as a function of the width of the central pseudorapidity gap Δη for Δη > 3, log 10 M X > 1.1, and log 10M Y > 1.1, a region dominated by DD. The cross sections integrated over these regions are found to be, respectively, 2.99 ± 0.02(stat) +0.32 -0.29(syst) mb, 1.18 ± 0.02(stat) ± 0.13(syst) mb, and 0.58 ± 0.01(stat) +0.13 -0.11(syst) mb, and are used to extract extrapolated total SD and DD cross sections. In addition, the inclusive differential cross section, dσ/dΔη F, for events with a pseudorapidity gap adjacent to the edge of the detector, is measured over Δη F = 8.4 units of pseudorapidity. The results are compared to those of other experiments and to theoretical predictions and found compatible with slowly rising diffractive cross sections as a function of center-of-mass energy.« less

Measurement of diffractive dissociation cross sections in p p collisions at √{s }=7 TeV

NASA Astrophysics Data System (ADS)

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Daci, N.; Heracleous, N.; Keaveney, J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Mora Herrera, C.; Pol, M. E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Du, R.; Jiang, C. H.; Plestina, R.; Tao, J.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Zou, W.; Avila, C.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Charlot, C.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Chabert, E. C.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Bontenackels, M.; Edelhoff, M.; Feld, L.; Hindrichs, O.; Klein, K.; Ostapchuk, A.; Perieanu, A.; Raupach, F.; Sammet, J.; Schael, S.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Erdmann, M.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Reithler, H.; Schmitz, S. A.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Weber, M.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Heister, A.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nowack, A.; Nugent, I. M.; Perchalla, L.; Pooth, O.; Stahl, A.; Asin, I.; Bartosik, N.; Behr, J.; Behrenhoff, W.; Behrens, U.; Bell, A. J.; Bergholz, M.; Bethani, A.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Garay Garcia, J.; Geiser, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Horton, D.; Jung, H.; Kalogeropoulos, A.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Krücker, D.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Lutz, B.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Novgorodova, O.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Ron, E.; Sahin, M. Ö.; Salfeld-Nebgen, J.; Saxena, P.; Schmidt, R.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Vargas Trevino, A. D. R.; Walsh, R.; Wissing, C.; Aldaya Martin, M.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Kirschenmann, H.; Klanner, R.; Kogler, R.; Lange, J.; Lapsien, T.; Lenz, T.; Marchesini, I.; Ott, J.; Peiffer, T.; Pietsch, N.; Poehlsen, J.; Poehlsen, T.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; De Boer, W.; Descroix, A.; Dierlamm, A.; Feindt, M.; Frensch, F.; Giffels, M.; Hartmann, F.; Hauth, T.; Husemann, U.; Katkov, I.; Kornmayer, A.; Kuznetsova, E.; Lobelle Pardo, P.; Mozer, M. U.; Müller, Th.; Nürnberg, A.; Quast, G.; Rabbertz, K.; Ratnikov, F.; Röcker, S.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Markou, A.; Markou, C.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Stiliaris, E.; Aslanoglou, X.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Bencze, G.; Hajdu, C.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Palinkas, J.; Szillasi, Z.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Swain, S. K.; Beri, S. B.; Bhatnagar, V.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, M.; Kumar, R.; Mittal, M.; Nishu, N.; Singh, J. B.; Kumar, Ashok; Kumar, Arun; Ahuja, S.; Bhardwaj, A.; Choudhary, B. C.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, V.; Banerjee, S.; Bhattacharya, S.; Chatterjee, K.; Dutta, S.; Gomber, B.; Jain, Sa.; Jain, Sh.; Khurana, R.; Modak, A.; Mukherjee, S.; Roy, D.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Dutta, D.; Kailas, S.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Mohanty, G. B.; Parida, B.; Sudhakar, K.; Wickramage, N.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Goldouzian, R.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Barbone, L.; Calabria, C.; Chhibra, S. S.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Selvaggi, G.; Silvestris, L.; Singh, G.; Venditti, R.; Zito, G.; Abbiendi, G.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Primavera, F.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Albergo, S.; Cappello, G.; Chiorboli, M.; Costa, S.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gallo, E.; Gonzi, S.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Tropiano, A.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Ferretti, R.; Ferro, F.; Lo Vetere, M.; Robutti, E.; Tosi, S.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Lucchini, M. T.; Malvezzi, S.; Manzoni, R. A.; Martelli, A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Fabozzi, F.; Iorio, A. O. M.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Azzi, P.; Bacchetta, N.; Bisello, D.; Branca, A.; Dall'Osso, M.; Dorigo, T.; Galanti, M.; Gasparini, F.; Giubilato, P.; Gozzelino, A.; Kanishchev, K.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Montecassiano, F.; Passaseo, M.; Pazzini, J.; Pegoraro, M.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Triossi, A.; Zotto, P.; Zucchetta, A.; Zumerle, G.; Gabusi, M.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vitulo, P.; Biasini, M.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Romeo, F.; Saha, A.; Santocchia, A.; Spiezia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Broccolo, G.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fiori, F.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Moon, C. S.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Squillacioti, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Vernieri, C.; Barone, L.; Cavallari, F.; D'imperio, G.; Del Re, D.; Diemoz, M.; Grassi, M.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Micheli, F.; Nourbakhsh, S.; Organtini, G.; Paramatti, R.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Soffi, L.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Casasso, S.; Costa, M.; Degano, A.; Demaria, N.; Finco, L.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Musich, M.; Obertino, M. M.; Ortona, G.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Potenza, A.; Romero, A.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Tamponi, U.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Gobbo, B.; La Licata, C.; Marone, M.; Schizzi, A.; Umer, T.; Zanetti, A.; Chang, S.; Kropivnitskaya, A.; Nam, S. K.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Kong, D. J.; Lee, S.; Oh, Y. D.; Park, H.; Sakharov, A.; Son, D. C.; Kim, T. J.; Kim, J. Y.; Song, S.; Choi, S.; Gyun, D.; Hong, B.; Jo, M.; Kim, H.; Kim, Y.; Lee, B.; Lee, K. S.; Park, S. K.; Roh, Y.; Choi, M.; Kim, J. H.; Park, I. C.; Ryu, G.; Ryu, M. S.; Choi, Y.; Choi, Y. K.; Goh, J.; Kim, D.; Kwon, E.; Lee, J.; Seo, H.; Yu, I.; Juodagalvis, A.; Komaragiri, J. R.; Md Ali, M. A. B.; Castilla-Valdez, H.; De La Cruz-Burelo, E.; Heredia-de La Cruz, I.; Hernandez-Almada, A.; Lopez-Fernandez, R.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Vazquez Valencia, F.; Pedraza, I.; Salazar Ibarguen, H. A.; Casimiro Linares, E.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Reucroft, S.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Khalid, S.; Khan, W. A.; Khurshid, T.; Shah, M. A.; Shoaib, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Romanowska-Rybinska, K.; Szleper, M.; Zalewski, P.; Brona, G.; Bunkowski, K.; Cwiok, M.; Dominik, W.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Wolszczak, W.; Bargassa, P.; Beirão Da Cruz E Silva, C.; Faccioli, P.; Ferreira Parracho, P. G.; Gallinaro, M.; Lloret Iglesias, L.; Nguyen, F.; Rodrigues Antunes, J.; Seixas, J.; Varela, J.; Vischia, P.; Gavrilenko, M.; Golutvin, I.; Gorbunov, I.; Karjavin, V.; Konoplyanikov, V.; Korenkov, V.; Kozlov, G.; Lanev, A.; Malakhov, A.; Matveev, V.; Mitsyn, V. V.; Moisenz, P.; Palichik, V.; Perelygin, V.; Shmatov, S.; Smirnov, V.; Tikhonenko, E.; Zarubin, A.; Golovtsov, V.; Ivanov, Y.; Kim, V.; Levchenko, P.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sulimov, V.; Uvarov, L.; Vavilov, S.; Vorobyev, A.; Vorobyev, An.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Safronov, G.; Semenov, S.; Spiridonov, A.; Stolin, V.; Vlasov, E.; Zhokin, A.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Mesyats, G.; Rusakov, S. V.; Vinogradov, A.; Belyaev, A.; Boos, E.; Ershov, A.; Gribushin, A.; Khein, L.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Lukina, O.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Tourtchanovitch, L.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Ekmedzic, M.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Battilana, C.; Calvo, E.; Cerrada, M.; Chamizo Llatas, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Domínguez Vázquez, D.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Navarro De Martino, E.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Soares, M. S.; Albajar, C.; de Trocóniz, J. F.; Missiroli, M.; Moran, D.; Brun, H.; Cuevas, J.; Fernandez Menendez, J.; Folgueras, S.; Gonzalez Caballero, I.; Brochero Cifuentes, J. A.; Cabrillo, I. J.; Calderon, A.; Duarte Campderros, J.; Fernandez, M.; Gomez, G.; Graziano, A.; Lopez Virto, A.; Marco, J.; Marco, R.; Martinez Rivero, C.; Matorras, F.; Munoz Sanchez, F. J.; Piedra Gomez, J.; Rodrigo, T.; Rodríguez-Marrero, A. Y.; Ruiz-Jimeno, A.; Scodellaro, L.; Vila, I.; Vilar Cortabitarte, R.; Abbaneo, D.; Auffray, E.; Auzinger, G.; Bachtis, M.; Baillon, P.; Ball, A. H.; Barney, D.; Benaglia, A.; Bendavid, J.; Benhabib, L.; Benitez, J. F.; Bernet, C.; Bianchi, G.; Bloch, P.; Bocci, A.; Bonato, A.; Bondu, O.; Botta, C.; Breuker, H.; Camporesi, T.; Cerminara, G.; Colafranceschi, S.; D'Alfonso, M.; d'Enterria, D.; Dabrowski, A.; David, A.; De Guio, F.; De Roeck, A.; De Visscher, S.; Di Marco, E.; Dobson, M.; Dordevic, M.; Dorney, B.; Dupont-Sagorin, N.; Elliott-Peisert, A.; Eugster, J.; Franzoni, G.; Funk, W.; Gigi, D.; Gill, K.; Giordano, D.; Girone, M.; Glege, F.; Guida, R.; Gundacker, S.; Guthoff, M.; Hammer, J.; Hansen, M.; Harris, P.; Hegeman, J.; Innocente, V.; Janot, P.; Kousouris, K.; Krajczar, K.; Lecoq, P.; Lourenço, C.; Magini, N.; Malgeri, L.; Mannelli, M.; Marrouche, J.; Masetti, L.; Meijers, F.; Mersi, S.; Meschi, E.; Moortgat, F.; Morovic, S.; Mulders, M.; Musella, P.; Orsini, L.; Pape, L.; Perez, E.; Perrozzi, L.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Pimiä, M.; Piparo, D.; Plagge, M.; Racz, A.; Rolandi, G.; Rovere, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Sharma, A.; Siegrist, P.; Silva, P.; Simon, M.; Sphicas, P.; Spiga, D.; Steggemann, J.; Stieger, B.; Stoye, M.; Takahashi, Y.; Treille, D.; Tsirou, A.; Veres, G. I.; Vlimant, J. R.; Wardle, N.; Wöhri, H. K.; Wollny, H.; Zeuner, W. D.; Bertl, W.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Renker, D.; Rohe, T.; Bachmair, F.; Bäni, L.; Bianchini, L.; Buchmann, M. A.; Casal, B.; Chanon, N.; Dissertori, G.; Dittmar, M.; Donegà, M.; Dünser, M.; Eller, P.; Grab, C.; Hits, D.; Hoss, J.; Lustermann, W.; Mangano, B.; Marini, A. C.; Martinez Ruiz del Arbol, P.; Masciovecchio, M.; Meister, D.; Mohr, N.; Nägeli, C.; Nessi-Tedaldi, F.; Pandolfi, F.; Pauss, F.; Peruzzi, M.; Quittnat, M.; Rebane, L.; Rossini, M.; Starodumov, A.; Takahashi, M.; Theofilatos, K.; Wallny, R.; Weber, H. A.; Amsler, C.; Canelli, M. F.; Chiochia, V.; De Cosa, A.; Hinzmann, A.; Hreus, T.; Kilminster, B.; Lange, C.; Millan Mejias, B.; Ngadiuba, J.; Robmann, P.; Ronga, F. J.; Taroni, S.; Verzetti, M.; Yang, Y.; Cardaci, M.; Chen, K. H.; Ferro, C.; Kuo, C. M.; Lin, W.; Lu, Y. J.; Volpe, R.; Yu, S. S.; Chang, P.; Chang, Y. H.; Chang, Y. W.; Chao, Y.; Chen, K. F.; Chen, P. H.; Dietz, C.; Grundler, U.; Hou, W.-S.; Kao, K. Y.; Lei, Y. J.; Liu, Y. F.; Lu, R.-S.; Majumder, D.; Petrakou, E.; Tzeng, Y. M.; Wilken, R.; Asavapibhop, B.; Srimanobhas, N.; Suwonjandee, N.; Adiguzel, A.; Bakirci, M. N.; Cerci, S.; Dozen, C.; Dumanoglu, I.; Eskut, E.; Girgis, S.; Gokbulut, G.; Gurpinar, E.; Hos, I.; Kangal, E. E.; Kayis Topaksu, A.; Onengut, G.; Ozdemir, K.; Ozturk, S.; Polatoz, A.; Sunar Cerci, D.; Tali, B.; Topakli, H.; Vergili, M.; Akin, I. V.; Bilin, B.; Bilmis, S.; Gamsizkan, H.; Karapinar, G.; Ocalan, K.; Sekmen, S.; Surat, U. E.; Yalvac, M.; Zeyrek, M.; Gülmez, E.; Isildak, B.; Kaya, M.; Kaya, O.; Cankocak, K.; Vardarlı, F. I.; Levchuk, L.; Sorokin, P.; Brooke, J. J.; Clement, E.; Cussans, D.; Flacher, H.; Goldstein, J.; Grimes, M.; Heath, G. P.; Heath, H. F.; Jacob, J.; Kreczko, L.; Lucas, C.; Meng, Z.; Newbold, D. M.; Paramesvaran, S.; Poll, A.; Senkin, S.; Smith, V. J.; Williams, T.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown, R. M.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Womersley, W. J.; Worm, S. D.; Baber, M.; Bainbridge, R.; Buchmuller, O.; Burton, D.; Colling, D.; Cripps, N.; Cutajar, M.; Dauncey, P.; Davies, G.; Della Negra, M.; Dunne, P.; Ferguson, W.; Fulcher, J.; Futyan, D.; Gilbert, A.; Hall, G.; Iles, G.; Jarvis, M.; Karapostoli, G.; Kenzie, M.; Lane, R.; Lucas, R.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mathias, B.; Nash, J.; Nikitenko, A.; Pela, J.; Pesaresi, M.; Petridis, K.; Raymond, D. M.; Rogerson, S.; Rose, A.; Seez, C.; Sharp, P.; Tapper, A.; Vazquez Acosta, M.; Virdee, T.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Leggat, D.; Leslie, D.; Martin, W.; Reid, I. D.; Symonds, P.; Teodorescu, L.; Turner, M.; Dittmann, J.; Hatakeyama, K.; Kasmi, A.; Liu, H.; Scarborough, T.; Charaf, O.; Cooper, S. I.; Henderson, C.; Rumerio, P.; Avetisyan, A.; Bose, T.; Fantasia, C.; Lawson, P.; Richardson, C.; Rohlf, J.; St. John, J.; Sulak, L.; Alimena, J.; Berry, E.; Bhattacharya, S.; Christopher, G.; Cutts, D.; Demiragli, Z.; Dhingra, N.; Ferapontov, A.; Garabedian, A.; Heintz, U.; Kukartsev, G.; Laird, E.; Landsberg, G.; Luk, M.; Narain, M.; Segala, M.; Sinthuprasith, T.; Speer, T.; Swanson, J.; Breedon, R.; Breto, G.; Calderon De La Barca Sanchez, M.; Chauhan, S.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Gardner, M.; Ko, W.; Lander, R.; Miceli, T.; Mulhearn, M.; Pellett, D.; Pilot, J.; Ricci-Tam, F.; Searle, M.; Shalhout, S.; Smith, J.; Squires, M.; Stolp, D.; Tripathi, M.; Wilbur, S.; Yohay, R.; Cousins, R.; Everaerts, P.; Farrell, C.; Hauser, J.; Ignatenko, M.; Rakness, G.; Takasugi, E.; Valuev, V.; Weber, M.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Hanson, G.; Heilman, J.; Ivova Rikova, M.; Jandir, P.; Kennedy, E.; Lacroix, F.; Long, O. R.; Luthra, A.; Malberti, M.; Nguyen, H.; Olmedo Negrete, M.; Shrinivas, A.; Sumowidagdo, S.; Wimpenny, S.; Andrews, W.; Branson, J. G.; Cerati, G. B.; Cittolin, S.; D'Agnolo, R. T.; Evans, D.; Holzner, A.; Kelley, R.; Klein, D.; Lebourgeois, M.; Letts, J.; Macneill, I.; Olivito, D.; Padhi, S.; Palmer, C.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Sudano, E.; Tadel, M.; Tu, Y.; Vartak, A.; Welke, C.; Würthwein, F.; Yagil, A.; Barge, D.; Bradmiller-Feld, J.; Campagnari, C.; Danielson, T.; Dishaw, A.; Flowers, K.; Franco Sevilla, M.; Geffert, P.; George, C.; Golf, F.; Gouskos, L.; Incandela, J.; Justus, C.; Mccoll, N.; Richman, J.; Stuart, D.; To, W.; West, C.; Yoo, J.; Apresyan, A.; Bornheim, A.; Bunn, J.; Chen, Y.; Duarte, J.; Mott, A.; Newman, H. B.; Pena, C.; Rogan, C.; Spiropulu, M.; Timciuc, V.; Wilkinson, R.; Xie, S.; Zhu, R. Y.; Azzolini, V.; Calamba, A.; Carlson, B.; Ferguson, T.; Iiyama, Y.; Paulini, M.; Russ, J.; Vogel, H.; Vorobiev, I.; Cumalat, J. P.; Ford, W. T.; Gaz, A.; Luiggi Lopez, E.; Nauenberg, U.; Smith, J. G.; Stenson, K.; Ulmer, K. A.; Wagner, S. R.; Alexander, J.; Chatterjee, A.; Chu, J.; Dittmer, S.; Eggert, N.; Mirman, N.; Nicolas Kaufman, G.; Patterson, J. R.; Ryd, A.; Salvati, E.; Skinnari, L.; Sun, W.; Teo, W. D.; Thom, J.; Thompson, J.; Tucker, J.; Weng, Y.; Winstrom, L.; Wittich, P.; Winn, D.; Abdullin, S.; Albrow, M.; Anderson, J.; Apollinari, G.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Cheung, H. W. K.; Chlebana, F.; Cihangir, S.; Elvira, V. D.; Fisk, I.; Freeman, J.; Gao, Y.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hanlon, J.; Hare, D.; Harris, R. M.; Hirschauer, J.; Hooberman, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Kaadze, K.; Klima, B.; Kreis, B.; Kwan, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, T.; Lykken, J.; Maeshima, K.; Marraffino, J. M.; Martinez Outschoorn, V. I.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mishra, K.; Mrenna, S.; Musienko, Y.; Nahn, S.; Newman-Holmes, C.; O'Dell, V.; Prokofyev, O.; Sexton-Kennedy, E.; Sharma, S.; Soha, A.; Spalding, W. J.; Spiegel, L.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vidal, R.; Whitbeck, A.; Whitmore, J.; Yang, F.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Carver, M.; Cheng, T.; Curry, D.; Das, S.; De Gruttola, M.; Di Giovanni, G. P.; Field, R. D.; Fisher, M.; Furic, I. K.; Hugon, J.; Konigsberg, J.; Korytov, A.; Kypreos, T.; Low, J. F.; Matchev, K.; Milenovic, P.; Mitselmakher, G.; Muniz, L.; Rinkevicius, A.; Shchutska, L.; Snowball, M.; Sperka, D.; Yelton, J.; Zakaria, M.; Hewamanage, S.; Linn, S.; Markowitz, P.; Martinez, G.; Rodriguez, J. L.; Adams, T.; Askew, A.; Bochenek, J.; Diamond, B.; Haas, J.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Prosper, H.; Veeraraghavan, V.; Weinberg, M.; Baarmand, M. M.; Hohlmann, M.; Kalakhety, H.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Bazterra, V. E.; Berry, D.; Betts, R. R.; Bucinskaite, I.; Cavanaugh, R.; Evdokimov, O.; Gauthier, L.; Gerber, C. E.; Hofman, D. J.; Khalatyan, S.; Kurt, P.; Moon, D. H.; O'Brien, C.; Silkworth, C.; Turner, P.; Varelas, N.; Albayrak, E. A.; Bilki, B.; Clarida, W.; Dilsiz, K.; Duru, F.; Haytmyradov, M.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Rahmat, R.; Sen, S.; Tan, P.; Tiras, E.; Wetzel, J.; Yetkin, T.; Yi, K.; Barnett, B. A.; Blumenfeld, B.; Bolognesi, S.; Fehling, D.; Gritsan, A. V.; Maksimovic, P.; Martin, C.; Swartz, M.; Baringer, P.; Bean, A.; Benelli, G.; Bruner, C.; Kenny, R. P.; Malek, M.; Murray, M.; Noonan, D.; Sanders, S.; Sekaric, J.; Stringer, R.; Wang, Q.; Wood, J. S.; Barfuss, A. F.; Chakaberia, I.; Ivanov, A.; Khalil, S.; Makouski, M.; Maravin, Y.; Saini, L. K.; Shrestha, S.; Skhirtladze, N.; Svintradze, I.; Gronberg, J.; Lange, D.; Rebassoo, F.; Wright, D.; Baden, A.; Belloni, A.; Calvert, B.; Eno, S. C.; Gomez, J. A.; Hadley, N. J.; Kellogg, R. G.; Kolberg, T.; Lu, Y.; Marionneau, M.; Mignerey, A. C.; Pedro, K.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Bauer, G.; Busza, W.; Cali, I. A.; Chan, M.; Di Matteo, L.; Dutta, V.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Klute, M.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Ma, T.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Stephans, G. S. F.; Stöckli, F.; Sumorok, K.; Velicanu, D.; Veverka, J.; Wyslouch, B.; Yang, M.; Zanetti, M.; Zhukova, V.; Dahmes, B.; Gude, A.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Mans, J.; Pastika, N.; Rusack, R.; Singovsky, A.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Gonzalez Suarez, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Malik, S.; Meier, F.; Snow, G. R.; Zvada, M.; Dolen, J.; Godshalk, A.; Iashvili, I.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Haley, J.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Velasco, M.; Won, S.; Brinkerhoff, A.; Chan, K. M.; Drozdetskiy, A.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Luo, W.; Lynch, S.; Marinelli, N.; Pearson, T.; Planer, M.; Ruchti, R.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hill, C.; Hughes, R.; Kotov, K.; Ling, T. Y.; Puigh, D.; Rodenburg, M.; Smith, G.; Winer, B. L.; Wolfe, H.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hebda, P.; Hunt, A.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Brownson, E.; Mendez, H.; Ramirez Vargas, J. E.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; De Mattia, M.; Gutay, L.; Hu, Z.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Leonardo, N.; Lopes Pegna, D.; Maroussov, V.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Yoo, H. D.; Zablocki, J.; Zheng, Y.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Ecklund, K. M.; Geurts, F. J. M.; Li, W.; Michlin, B.; Padley, B. P.; Redjimi, R.; Roberts, J.; Zabel, J.; Betchart, B.; Bodek, A.; Covarelli, R.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Khukhunaishvili, A.; Petrillo, G.; Vishnevskiy, D.; Ciesielski, R.; Demortier, L.; Goulianos, K.; Lungu, G.; Mesropian, C.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Kaplan, S.; Lath, A.; Panwalkar, S.; Park, M.; Patel, R.; Salur, S.; Schnetzer, S.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Khotilovich, V.; Krutelyov, V.; Montalvo, R.; Osipenkov, I.; Pakhotin, Y.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Sakuma, T.; Suarez, I.; Tatarinov, A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kovitanggoon, K.; Kunori, S.; Lee, S. W.; Libeiro, T.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sharma, M.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wood, J.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Lazaridis, C.; Levine, A.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Sarangi, T.; Savin, A.; Smith, W. H.; Taylor, D.; Verwilligen, P.; Vuosalo, C.; Woods, N.; CMS Collaboration

2015-07-01

Measurements of diffractive dissociation cross sections in p p collisions at √{s }=7 TeV are presented in kinematic regions defined by the masses MX and MY of the two final-state hadronic systems separated by the largest rapidity gap in the event. Differential cross sections are measured as a function of ξX=MX2/s in the region -5.5 3 , log10MX>1.1 , and log10MY>1.1 , a region dominated by DD. The cross sections integrated over these regions are found to be, respectively, 2.99 ±0.02 (stat)-0.29+0.32(syst) mb , 1.18 ±0.02 (stat) ±0.13 (syst) mb , and 0.58 ±0.01 (stat)-0.11+0.13(syst) mb , and are used to extract extrapolated total SD and DD cross sections. In addition, the inclusive differential cross section, d σ /d Δ ηF , for events with a pseudorapidity gap adjacent to the edge of the detector, is measured over Δ ηF=8.4 units of pseudorapidity. The results are compared to those of other experiments and to theoretical predictions and found compatible with slowly rising diffractive cross sections as a function of center-of-mass energy.

Quantitative measurements of magnetic vortices using position resolved diffraction in Lorentz STEM

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

Zaluzec, N. J.

2002-03-05

A number of electron column techniques have been developed over the last forty years to permit visualization of magnetic fields in specimens. These include: Fresnel imaging, Differential Phase Contrast, Electron Holography and Lorentz STEM. In this work we have extended the LSTEM methodology using Position Resolved Diffraction (PRD) to quantitatively measure the in-plane electromagnetic fields of thin film materials. The experimental work reported herein has been carried out using the ANL AAEM HB603Z 300 kV FEG instrument 5. In this instrument, the electron optical column was operated in a zero field mode, at the specimen, where the objective lens ismore » turned off and the probe forming lens functions were reallocated to the C1, C2, and C3 lenses. Post specimen lenses (P1, P2, P3, P4) were used to magnify the transmitted electrons to a YAG screen, which was then optically transferred to a Hamamatsu ORCA ER CCD array. This CCD was interfaced to an EmiSpec Data Acquisition System and the data was subsequently transferred to an external computer system for detailed quantitative analysis. In Position Resolved Diffraction mode, we digitally step a focused electron probe across the region of interest of the specimen while at the same time recording the complete diffraction pattern at each point in the scan.« less

Single-diffractive production of dijets within the kt-factorization approach

NASA Astrophysics Data System (ADS)

Łuszczak, Marta; Maciuła, Rafał; Szczurek, Antoni; Babiarz, Izabela

2017-09-01

We discuss single-diffractive production of dijets. The cross section is calculated within the resolved Pomeron picture, for the first time in the kt-factorization approach, neglecting transverse momentum of the Pomeron. We use Kimber-Martin-Ryskin unintegrated parton (gluon, quark, antiquark) distributions in both the proton as well as in the Pomeron or subleading Reggeon. The unintegrated parton distributions are calculated based on conventional mmht2014nlo parton distribution functions in the proton and H1 Collaboration diffractive parton distribution functions used previously in the analysis of diffractive structure function and dijets at HERA. For comparison, we present results of calculations performed within the collinear-factorization approach. Our results remain those obtained in the next-to-leading-order approach. The calculation is (must be) supplemented by the so-called gap survival factor, which may, in general, depend on kinematical variables. We try to describe the existing data from Tevatron and make detailed predictions for possible LHC measurements. Several differential distributions are calculated. The E¯T, η ¯ and xp ¯ distributions are compared with the Tevatron data. A reasonable agreement is obtained for the first two distributions. The last one requires introducing a gap survival factor which depends on kinematical variables. We discuss how the phenomenological dependence on one kinematical variable may influence dependence on other variables such as E¯T and η ¯. Several distributions for the LHC are shown.

Target Acquisition for Projectile Vision-Based Navigation

DTIC Science & Technology

2014-03-01

Future Work 20 8. References 21 Appendix A. Simulation Results 23 Appendix B. Derivation of Ground Resolution for a Diffraction-Limited Pinhole Camera...results for visual acquisition (left) and target recognition (right). ..........19 Figure B-1. Differential object and image areas for pinhole camera...projectile and target (measured in terms of the angle ) will depend on target heading. In particular, because we have aligned the x axis along the

Nanoscale contact resistance of V2O5 xerogel films developed by nanostructured powder

NASA Astrophysics Data System (ADS)

Bera, Biswajit; Sekhar Das, Pradip; Bhattacharya, Manjima; Ghosh, Swapankumar; Mukhopadhyay, Anoop Kumar; Dey, Arjun

2016-03-01

Here we report the synthesis of V2O5 nanostructures by a fast, simple, cost-effective, low-temperature chemical process; followed by the deposition of V2O5 xerogel thin films on a glass substrate by a sol-gel route. Phase analysis, phase transition, microstructural and electronic characterization studies are carried out by x-ray diffraction, texture coefficient analysis, field emission scanning electron microscopy, transmission electron microscopy (TEM), related selected area electron diffraction pattern (SAED) analysis, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis, differential scanning calorimetry, and x-ray photoelectron spectroscopy techniques. Confirmatory TEM and SAED data analysis prove further that in this polycrystalline powder there is a unique localized existence of purely single crystalline V2O5 powder with a preferred orientation in the (0 1 0) direction. The most interesting result obtained in the present work is that the xerogel thin films exhibit an inherent capability to enhance the intrinsic resistance against contact induced deformations as more external load is applied during the nanoindentation experiments. In addition, both the nanohardness and Young’s modulus of the films are found to be insensitive to load variations (e.g. 1 to 7 mN). These results are explained in terms of microstructural parameters, e.g. porosity and structural configuration.

Thermodynamics of mercaptopurine dehydration.

PubMed

Niazi, S

1978-04-01

The hydrate form of mercaptopurine was shown to undergo peritectic decomposition of its water molecule, localized dissolution, and dehydration around 125 degrees. The anhydrate form was prepared by a thermal method, whose effectiveness was confirmed by X-ray diffraction, NMR spectroscopy, and differential scanning calorimetry. The activation energy for mercaptopurine dehydration calculated by various methods ranged from 45.74 to 63.04 kcal/mole. The dehydration enthalpy was calculated to be 8.27 kcal/mole by differential scanning calorimetry. The solution enthalpy for the hydrate was calculated to be 4.85 kcal/mole from its saturation solubility and differential scanning calorimetry. Anhydrate solubility in water was calculated based on initial dissolution rate data since the anhydrate converts to hydrate in aqueous media. The high degree of stability against interconversion of the hydrate and anhydrate forms and the higher solubility of the anhydrate suggest that use of the anhydrate might improve mercaptopurine bioavailability.

Detection of compatibility between baclofen and excipients with aid of infrared spectroscopy and chemometry

NASA Astrophysics Data System (ADS)

Rojek, Barbara; Wesolowski, Marek; Suchacz, Bogdan

2013-12-01

In the paper infrared (IR) spectroscopy and multivariate exploration techniques: principal component analysis (PCA) and cluster analysis (CA) were applied as supportive methods for the detection of physicochemical incompatibilities between baclofen and excipients. In the course of research, the most useful rotational strategy in PCA proved to be varimax normalized, while in CA Ward's hierarchical agglomeration with Euclidean distance measure enabled to yield the most interpretable results. Chemometrical calculations confirmed the suitability of PCA and CA as the auxiliary methods for interpretation of infrared spectra in order to recognize whether compatibilities or incompatibilities between active substance and excipients occur. On the basis of IR spectra and the results of PCA and CA it was possible to demonstrate that the presence of lactose, β-cyclodextrin and meglumine in binary mixtures produce interactions with baclofen. The results were verified using differential scanning calorimetry, differential thermal analysis, thermogravimetry/differential thermogravimetry and X-ray powder diffraction analyses.

Evidence of an enhanced nuclear radius of the α -halo state via α +12C inelastic scattering

NASA Astrophysics Data System (ADS)

Ito, Makoto

2018-04-01

Evidence of the enhanced nuclear radius in the Hoyle rotational state, 22+, is derived from the differential cross sections in α +12C inelastic scattering. The prominent shrinkage is observed in the differential cross section of the 22+ state in comparison to the yrast 21+ state, and this shrinkage is the first evidence of the enhanced nuclear radius which originates from the 3 α structure in the 22+ state. A diffraction formula, that is, Blair's phase rule, is applied to the differential cross sections, and the present analysis predicts an enhancement of 0.6 to 1.0 fm in the nuclear radius of the 22+ state in comparison to the radius of the yrast 21+, which is considered to have a normal nuclear radius. Constraint on the recent ab initio calculation for 3 α states in 12C is also discussed.

OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. IV. OBSERVATIONS OF KEPLER, CoRoT, AND HIPPARCOS STARS FROM THE GEMINI NORTH TELESCOPE

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

Horch, Elliott P.; Howell, Steve B.; Everett, Mark E.

2012-12-01

We present the results of 71 speckle observations of binary and unresolved stars, most of which were observed with the DSSI speckle camera at the Gemini North Telescope in 2012 July. The main purpose of the run was to obtain diffraction-limited images of high-priority targets for the Kepler and CoRoT missions, but in addition, we observed a number of close binary stars where the resolution limit of Gemini was used to better determine orbital parameters and/or confirm results obtained at or below the diffraction limit of smaller telescopes. Five new binaries and one triple system were discovered, and first orbitsmore » are calculated for other two systems. Several systems are discussed in detail.« less

Crystallization of heavy metal fluoride glasses

NASA Technical Reports Server (NTRS)

Bansal, Narottam P.; Bruce, Allan J.; Doremus, R. H.; Moynihan, C. T.

1984-01-01

The kinetics of crystallization of a number of fluorozirconate glasses were studied using isothermal and dynamic differential scanning calorimetry and X-ray diffraction. The addition of the fluorides LiF, NaF, AlF3, LaF3 to a base glass composition of ZrF4-BaF2 reduced the tendency to crystallize, probably by modifying the viscosity-temperature relation. ZrF4-BaF2-LaF3-AlF3-NaF glass was the most stable against devitrification and perhaps is the best composition for optical fibers with low scattering loss. Some glasses first crystallize out into metastable beta-BaZr2F10 and beta-BaZrF6 phases, which transform into the most stable alpha-phases when heated to higher temperatures. The size of the crystallites was estimated to be about 600 A from X-ray diffraction.

Thermal, spectroscopic and structural characterization of isostructural phase transition in 4-hydroxybenzaldehyde

NASA Astrophysics Data System (ADS)

Panicker, Lata

2018-05-01

Polycrystalline samples of 4-hydroxybenzaldehyde (4-HOBAL) were investigated using differential scanning calorimeter (DSC), Raman spectroscopy and X-ray powder diffraction. The DSC data indicated that 4-HOBAL on heating undergoes a polymorphic transformation from polymorph I to polymorph II. The polymorph II formed remains metastable at ambient condition and transforms to polymorph I when annealed at ambient temperature for more than seven days. The structural information of polymorphs I and II obtained using its X-ray powder diffraction patterns indicated that 4-HOBAL undergoes an isostructural phase transition from polymorph I (monoclinic, P21/c) to polymorph II (monoclinic, P21/c). Raman data suggest that this structural change is associated with some change in its molecular interactions. Thus, in 4-HOBAL the polymorphic phase transformation (II to I) even though energetically favoured is kinetically hindered.

Thermal behaviour and microanalysis of coal subbituminus

NASA Astrophysics Data System (ADS)

Heriyanti; Prendika, W.; Ashyar, R.; Sutrisno

2018-04-01

Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) is used to study the thermal behaviour of sub-bituminous coal. The DSC experiment was performed in air atmosphere up to 125 °C at a heating rate of 25 °C min1. The DSC curve showed that the distinct transitional stages in the coal samples studied. Thermal heating temperature intervals, peak and dissociation energy of the coal samples were also determined. The XRD analysis was used to evaluate the diffraction pattern and crystal structure of the compounds in the coal sample at various temperatures (25-350 °C). The XRD analysis of various temperatures obtained compounds from the coal sample, dominated by quartz (SiO2) and corundum (Al2O3). The increase in temperature of the thermal treatment showed a better crystal formation.

Issues in Optical Diffraction Theory

PubMed Central

Mielenz, Klaus D.

2009-01-01

This paper focuses on unresolved or poorly documented issues pertaining to Fresnel’s scalar diffraction theory and its modifications. In Sec. 2 it is pointed out that all thermal sources used in practice are finite in size and errors can result from insufficient coherence of the optical field. A quarter-wave criterion is applied to show how such errors can be avoided by placing the source at a large distance from the aperture plane, and it is found that in many cases it may be necessary to use collimated light as on the source side of a Fraunhofer experiment. If these precautions are not taken the theory of partial coherence may have to be used for the computations. In Sec. 3 it is recalled that for near-zone computations the Kirchhoff or Rayleigh-Sommerfeld integrals are applicable, but fail to correctly describe the energy flux across the aperture plane because they are not continuously differentiable with respect to the assumed geometrical field on the source side. This is remedied by formulating an improved theory in which the field on either side of a semi-reflecting screen is expressed as the superposition of mutually incoherent components which propagate in the opposite directions of the incident and reflected light. These components are defined as linear combinations of the Rayleigh-Sommerfeld integrals, so that they are rigorous solutions of the wave equation as well as continuously differentiable in the aperture plane. Algorithms for using the new theory for computing the diffraction patterns of circular apertures and slits at arbitrary distances z from either side of the aperture (down to z = ± 0.0003 λ) are presented, and numerical examples of the results are given. These results show that the incident geometrical field is modulated by diffraction before it reaches the aperture plane while the reflected field is spilled into the dark space. At distances from the aperture which are large compared to the wavelength λ these field expressions are reduced to the usual ones specified by Fresnel’s theory. In the specific case of a diffracting half plane the numerical results obtained were practically the same as those given by Sommerfeld’s rigorous theory. The modified theory developed in this paper is based on the explicit assumption that the scalar theory of light cannot explain plolarization effects. This premise is justified in Sec. 4, where it is shown that previous attempts to do so have produced dubious results. PMID:27504215

Comparison of Plasma Exosomes by Differential Ultracentrifugation and Solvent Precipitation Methods.

PubMed

Peng, Qiao; Zhang, Jing; Zhou, Gang

2018-06-01

Emerging evidence has identified that exosomes play a pivotal role in intercellular signal transmission. However, the standardized purification techniques to isolate high quality exosomes are still deficient at present. This study was to evaluate reproducibility and efficiency of differential ultracentrifugation and solvent precipitation-based kits by isolating plasma-derived exosomes from oral lichen planus patients. Morphology, exosomal biomarkers, particle size distribution, proteomic components, and protein yield of isolated exosomes were evaluated by transmission electron microscope, western blot, laser diffraction instrument, Coomassie staining, and BCA protein assay kit, respectively. TEM displayed representative cup-shaped morphology of exosomes and western blot identified exosomal biomarkers CD9 and CD63. The size distribution showed that particles by differential ultracentrifugation were mainly from 26.15 nm to 166.5 nm, while some of the particles obtained by solvent precipitation kits were larger than 1,000 nm. In addition, exosomes isolated by solvent precipitation kits showed a significantly higher amount of protein yield due to plasma albumin contamination. Both differential ultracentrifugation and precipitation based kits could successfully isolate plasma exosomes, and exosomes by differential ultracentrifugation were purer and more appropriate for further proteomic analysis.

Microscopy of biological sample through advanced diffractive optics from visible to X-ray wavelength regime.

PubMed

Di Fabrizio, Enzo; Cojoc, Dan; Emiliani, Valentina; Cabrini, Stefano; Coppey-Moisan, Maite; Ferrari, Enrico; Garbin, Valeria; Altissimo, Matteo

2004-11-01

The aim of this report is to demonstrate a unified version of microscopy through the use of advanced diffractive optics. The unified scheme derives from the technical possibility of realizing front wave engineering in a wide range of electromagnetic spectrum. The unified treatment is realized through the design and nanofabrication of phase diffractive elements (PDE) through which wave front beam shaping is obtained. In particular, we will show applications, by using biological samples, ranging from micromanipulation using optical tweezers to X-ray differential interference contrast (DIC) microscopy combined with X-ray fluorescence. We report some details on the design and physical implementation of diffractive elements that besides focusing also perform other optical functions: beam splitting, beam intensity, and phase redistribution or mode conversion. Laser beam splitting is used for multiple trapping and independent manipulation of micro-beads surrounding a cell as an array of tweezers and for arraying and sorting microscopic size biological samples. Another application is the Gauss to Laguerre-Gauss mode conversion, which allows for trapping and transfering orbital angular momentum of light to micro-particles immersed in a fluid. These experiments are performed in an inverted optical microscope coupled with an infrared laser beam and a spatial light modulator for diffractive optics implementation. High-resolution optics, fabricated by means of e-beam lithography, are demonstrated to control the intensity and the phase of the sheared beams in x-ray DIC microscopy. DIC experiments with phase objects reveal a dramatic increase in image contrast compared to bright-field x-ray microscopy. Besides the topographic information, fluorescence allows detection of certain chemical elements (Cl, P, Sc, K) in the same setup, by changing the photon energy of the x-ray beam. (c) 2005 Wiley-Liss, Inc.

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

Asha, S.; Sangappa,; Sanjeev, Ganesh, E-mail: ganeshanjeev@rediffmail.com

Radiation-induced changes in Bombyx mori silk fibroin (SF) films under electron irradiation were investigated and correlated with dose. SF films were irradiated in air at room temperature using 8 MeV electron beam in the range 0-150 kGy. Various properties of the irradiated SF films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Electron irradiation was found to induce changes in the physical and thermal properties, depending on the radiation dose.

Thermal annealing of natural, radiation-damaged pyrochlore

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

Zietlow, Peter; Beirau, Tobias; Mihailova, Boriana

Abstract Radiation damage in minerals is caused by the α-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400–1000 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia [6.4 wt% Th, 23.1·10

Structural studies of crystalline forms of triamterene with carboxylic acid, GRAS and API molecules

PubMed Central

Rehman, Abida

2018-01-01

Pharmaceutical salt solvates (dimethyl sulfoxide, DMSO) of the drug triamterene with the coformers acetic, succinic, adipic, pimelic, azelaic and nicotinic acid and ibuprofen are prepared by liquid-assisted grinding and solvent-evaporative crystallization. The modified ΔpK a rule as proposed by Cruz-Cabeza [(2012 ▸). CrystEngComm, 14, 6362–6365] is in close agreement with the results of this study. All adducts were characterized by X-ray diffraction and thermal analytical techniques, including single-crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry and thermal gravimetric analysis. Hydrogen-bonded motifs combined to form a variety of extended tapes and sheets. Analysis of the crystal structures showed that all adducts existed as salt solvates and contained the amino­pyridinium–carboxyl­ate heterodimer, except for the solvate containing triamterene, ibuprofen and DMSO, as a result of the presence of a strong and stable hemitriamterenium duplex. A search of the Cambridge Structural Database (CSD 5.36, Version 1.18) to determine the frequency of occurrence of the putative supramolecular synthons found in this study showed good agreement with previous work. PMID:29755747

Characterisation of the wall-slip during extrusion of heavy-clay products

NASA Astrophysics Data System (ADS)

Kocserha, I.; Gömze, A. L.; Kulkov, S.; Kalatur, E.; Buyakova, S. P.; Géber, R.; Buzimov, A. Y.

2017-01-01

During extrusion through the extrusion die, heavy-clay compounds are usually show plug flow with extensive slip at the wall of the die. In this study, the viscosity and the thickness of the slip layer were investigated. For the examination a brick-clay from Malyi (Hungary) deposit was applied as a raw material. The clay was characterised by XRPD, BET, SEM and granulometry. As the slip layer consists of suspension of the fine clay fraction so the clay minerals content of the clay (d<2µm) was separated by the help of sedimentation. The viscosity of suspension with different water content was measured by means of rotational viscosimeter. The thickness of the slip layer was calculated from the measured viscosity and other data obtained from an earlier study with capillary rheometer. The calculated thickness value showed a tendency to reach a limit value by increasing the extrusion speed.

One-step continuous extrusion process for the manufacturing of solid dispersions.

PubMed

Maniruzzaman, M; Nair, A; Scoutaris, N; Bradley, Michael S A; Snowden, M J; Douroumis, D

2015-12-30

The purpose of this study was to evaluate the performance of synthetic magnesium aluminometasilicate (MAS) as a novel inorganic carrier in hot melt extrusion (HME) processing of indomethacin (IND) for the development of solid dispersions. A continuous extrusion process at various IND/excipient blend ratios (20%, 30% and 40%) was performed using a twin-screw extruder. Physicochemical characterization carried out by SEM, DSC, and XRPD demonstrated the presence of IND in amorphous nature within the porous network of the inorganic material for all extruded formulations. Further, AFM and FTIR studies revealed a single-phase amorphous system and intermolecular H-bonding formation. The IND/MAS extrudates showed enhanced INM dissolution rates within 100% been released within 1h. Stability studies under accelerated conditions (40°C, RH 75%) showed that MAS retained the physical stability of the amorphous solid dispersions even at high drug loadings for 12 months. Copyright © 2015 Elsevier B.V. All rights reserved.

Spectroscopic and theoretical study of the charge transfer interaction effect on the vibrational modes and nonlinear optical properties in L-asparaginium nitrate crystal

NASA Astrophysics Data System (ADS)

Elleuch, Nabil; Abid, Younes; Feki, Habib

2016-09-01

Single crystals of L-asparaginium nitrate (LAsnN) were grown by slow evaporation technique. To confirm the crystalline nature of the obtained compound, samples were the subject of an XRPD. The density functional theory (DFT) computations were carried out at B3LYP/6-31G (d) level to reach the optimized geometry, the vibrational spectra and the NLO properties. The excellent agreement between simulated and observed vibrational spectra led to a reliable vibrational assignment. To demonstrate the various charge transfer interactions that stabilize the compound and led to the high nonlinear optical activity, NBO analysis was performed. Also, owing to the hydrogen bond formation, a lowering in the HOMO-LUMO energy gap is noticed. Moreover, as a result of the charge transfer interactions, the symmetry of the nitrate ions was lost and some forbidden modes were excited.

In Situ Identification of Nanoparticle Structural Information Using Optical Microscopy.

PubMed

Culver, Kayla S B; Liu, Tingting; Hryn, Alexander J; Fang, Ning; Odom, Teri W

2018-05-11

Diffraction-limited optical microscopy lacks the resolution to characterize directly nanoscale features of single nanoparticles. This paper describes how surprisingly rich structural features of small gold nanostars can be identified using differential interference contrast (DIC) microscopy. First, we established a library of structure-property relationships between nanoparticle shape and DIC optical image and then validated the correlation with electrodynamic simulations and electron microscopy. We found that DIC image patterns of single nanostars could be differentiated between 2D and 3D geometries. Also, DIC images could elucidate the symmetry properties and orientation of nanoparticles. Finally, we demonstrated how this wide-field optical technique can be used for in situ characterization of single nanoparticles rotating at a glass-water interface.

Determination of thermoelastic material properties by differential heterodyne detection of impulsive stimulated thermal scattering

PubMed Central

Verstraeten, B.; Sermeus, J.; Salenbien, R.; Fivez, J.; Shkerdin, G.; Glorieux, C.

2015-01-01

The underlying working principle of detecting impulsive stimulated scattering signals in a differential configuration of heterodyne diffraction detection is unraveled by involving optical scattering theory. The feasibility of the method for the thermoelastic characterization of coating-substrate systems is demonstrated on the basis of simulated data containing typical levels of noise. Besides the classical analysis of the photoacoustic part of the signals, which involves fitting surface acoustic wave dispersion curves, the photothermal part of the signals is analyzed by introducing thermal wave dispersion curves to represent and interpret their grating wavelength dependence. The intrinsic possibilities and limitations of both inverse problems are quantified by making use of least and most squares analysis. PMID:26236643

Scattering on two Aharonov-Bohm vortices

NASA Astrophysics Data System (ADS)

Bogomolny, E.

2016-12-01

The problem of two Aharonov-Bohm (AB) vortices for the Helmholtz equation is examined in detail. It is demonstrated that the method proposed by Myers (1963 J. Math. Phys. 6 1839) for slit diffraction can be generalised to obtain an explicit solution for AB vortices. Due to the singular nature of AB interaction the Green function and scattering amplitude for two AB vortices obey a series of partial differential equations. Coefficients entering these equations, fulfil ordinary non-linear differential equations whose solutions can be obtained by solving the Painlevé III equation. The asymptotics of necessary functions for very large and very small vortex separations are calculated explicitly. Taken together, this means that the problem of two AB vortices is exactly solvable.

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

Zhang, Baozhuo; Young, Marcus L.

Many technological applications of austenitic shape memory alloys (SMAs) involve cyclical mechanical loading and unloading in order to take advantage of pseudoelasticity. In this paper, we investigated the effect of mechanical bending of pseudoelastic NiTi SMA wires using high-energy synchrotron radiation X-ray diffraction (SR-XRD). Differential scanning calorimetry was performed to identify the phase transformation temperatures. Scanning electron microscopy images show that micro-cracks in compressive regions of the wire propagate with increasing bend angle, while tensile regions tend not to exhibit crack propagation. SR-XRD patterns were analyzed to study the phase transformation and investigate micromechanical properties. By observing the various diffraction peaks such as the austenite (200) and the martensite (more » $${\\bar 1}12$$), ($${\\bar 1}03$$), ($${\\bar 1}11$$), and (101) planes, intensities and residual strain values exhibit strong anisotropy, depending upon whether the sample is in compression or tension during bending.« less

Synchrotron Study on Crystallization Kinetics of Milk Fat under Shear Flow

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

Mazzanti, G.; Marangoni, A; Idziak, S

A detailed synchrotron X-ray diffraction study on the kinetics of crystallization of anhydrous milk fat (AMF) and milk fat triacylglycerols (MFT) was done in a Couette cell at 17 C, 17.5 C and 20 C under shear rates between 0 and 2880 s-1. We observed shear-induced acceleration of the transition from phase ? to ?? and the presence of crystalline orientation, but no effect of shear on the onset time of phase ? was observed. A two stage regime was observed for the growth of phase ??. The first stage follows a series-parallel system of differential equations describing the conversionmore » between liquid and crystalline phases. The second stage follows a diffusion-controlled regime. These mechanisms are consistent with the crystalline orientation, the growth of the crystalline domains and the observed displacement of the diffraction peak positions. The absence of the polar lipids explains the faster kinetics of MFT.« less

Exclusive diffractive production of real photons and vector mesons in a factorized Regge-pole model with nonlinear Pomeron trajectory

NASA Astrophysics Data System (ADS)

Fazio, S.; Fiore, R.; Jenkovszky, L.; Lavorini, A.

2012-03-01

Exclusive diffractive production of real photons and vector mesons in ep collisions has been studied at HERA in a wide kinematic range. Here we present and discuss a Regge-type model of real photon production (deeply virtual Compton scattering), as well as production of vector mesons treated on the same footing by using an extension of a factorized Regge-pole model proposed earlier. The model has been fitted to the HERA data. Despite the very small number of the free parameters, the model gives a satisfactory description of the experimental data, both for the total cross section as a function of the photon virtuality Q2 or the energy W in the center of mass of the γ*p system, and the differential cross sections as a function of the squared four-momentum transfer t with fixed Q2 and W.

Poly(fumaric-co-sebacic anhydride). A degradation study as evaluated by FTIR, DSC, GPC and X-ray diffraction.

PubMed

Santos, C A; Freedman, B D; Leach, K J; Press, D L; Scarpulla, M; Mathiowitz, E

1999-06-28

The degradation of three poly(fumaric-co-sebacic anhydride) [P(FA:SA)] copolymers is examined in a composition of microspheres made by the hot melt encapsulation process. The emergence of low molecular weight oligomers occurs during degradation of the copolymer microspheres, as evidenced by a variety of characterization methods. Characterization was conducted to determine the extent of degradation of the polyanhydride microspheres using Fourier-transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and X-ray diffraction. It is demonstrated that degradation of P(FA:SA) is greatly accelerated at basic pH, yet there is little difference between degradation in neutral and acidic buffers. A good correlation exists between the results of each characterization method, which allows a better understanding of the degradation process and the resulting formation of low molecular weight oligomers in poly(fumaric-co-sebacic anhydride).

Room temperature synthesis of Cu₂O nanospheres: optical properties and thermal behavior.

PubMed

Nunes, Daniela; Santos, Lídia; Duarte, Paulo; Pimentel, Ana; Pinto, Joana V; Barquinha, Pedro; Carvalho, Patrícia A; Fortunato, Elvira; Martins, Rodrigo

2015-02-01

The present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.

A new polymorph of 4'-hydroxyvalerophenone revealed by thermoanalytical and X-ray diffraction studies

NASA Astrophysics Data System (ADS)

Lopes, Cátia S. D.; Bernardes, Carlos E. S.; Piedade, M. Fátima M.; Diogo, Hermínio P.; da Piedade, Manuel E. Minas

2017-04-01

A new polymorph of 1-(4-hydroxyphenyl)pentan-1-one (4'-hydroxyvalerophenone, HVP) was identified by using differential scanning calorimetry, hot stage microscopy, and X-ray powder diffraction. This novel crystal form (form II) was obtained by crystallization from melt. It has a fusion temperature of T fus = 324.3 ± 0.2 K and an enthalpy of fusion Δfus H m o = 18.14±0.18 kJ·mol-1. These values are significantly lower than those observed for the previously known phase (form I, monoclinic, space group P21/ c, T fus = 335.6 ± 0.7 K; Δfus H m o = 26.67±0.04 kJ·mol-1), which can be prepared by crystallization from ethanol. The results here obtained, therefore, suggest that form I is thermodynamically more stable than the newly identified form II and, furthermore, that the two polymorphs are monotropically related.

Advancing X-ray scattering metrology using inverse genetic algorithms.

PubMed

Hannon, Adam F; Sunday, Daniel F; Windover, Donald; Kline, R Joseph

2016-01-01

We compare the speed and effectiveness of two genetic optimization algorithms to the results of statistical sampling via a Markov chain Monte Carlo algorithm to find which is the most robust method for determining real space structure in periodic gratings measured using critical dimension small angle X-ray scattering. Both a covariance matrix adaptation evolutionary strategy and differential evolution algorithm are implemented and compared using various objective functions. The algorithms and objective functions are used to minimize differences between diffraction simulations and measured diffraction data. These simulations are parameterized with an electron density model known to roughly correspond to the real space structure of our nanogratings. The study shows that for X-ray scattering data, the covariance matrix adaptation coupled with a mean-absolute error log objective function is the most efficient combination of algorithm and goodness of fit criterion for finding structures with little foreknowledge about the underlying fine scale structure features of the nanograting.

Syntheses, structure characterization and dissolution of two novel cocrystals of febuxostat

NASA Astrophysics Data System (ADS)

Kang, Yanlei; Gu, Jianming; Hu, Xiurong

2017-02-01

Febuxostat was investigated due to its significant effect in the treatment of gout. However, its poor water solubility hinder its potential applications. In recent years, cocrystals have increasingly being applied to enhance the drug solubility. To improve the solubility, two cocrystals of Febuxostat were synthesized through the method of cooling crystallization. The prepared cocrystals febuxostat-isonicotinamide(FEB-INA) and febuxostat-arginine(FEB-Arg) were studied by microscopical observation, Powder X-Ray Diffraction(PXRD), Single Crystal X-ray Diffraction, Differential Scanning Calorimetry(DSC), and infrared spectrometry. At the same time, the cocrystals' solubility and dissolution rate were explored. Both the cocrystals showed higher solubility compared to the pure drug. The FEB-Arg cocrystal enhanced about 900 times of solubility compared to the pure drug. The current study proved that cocrystallization can be a better way to enhance the solubility of the poorly water-soluble drug.

Application of Electron Backscatter Diffraction to evaluate the ASR risk of concrete aggregates

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

Rößler, C., E-mail: christiane.roessler@uni-weimar.de; Möser, B.; Giebson, C.

Alkali-Silica Reaction (ASR) is a frequent cause of reduced concrete durability. Eliminating the application of alkali reactive aggregates would reduce the quantity of ASR concrete deterioration in the field. This study introduces an Electron Backscatter Diffraction (EBSD) technique to distinguish the ASR risk of slow-late reacting aggregates by measuring microstructural properties of quartz. Quantifying the amount of quartz grain boundaries and the associated misorientation of grains can thereby be used to differentiate microstructures bearing an ASR risk. It is also shown that dissolution of quartz in high pH environments occurs along quartz grain and subgrain boundaries. Results of EBSD analysismore » are compared with ASR performance testing on concrete prisms and optical light microscopy characterization of quartz microstructure. EBSD opens new possibilities to quantitatively characterize microstructure of quartz in concrete aggregates with respect to ASR. This leads to a better understanding on the actual cause of ASR.« less

X-ray diffraction, IR spectroscopy and thermal characterization of partially hydrolyzed guar gum.

PubMed

Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

2012-05-01

Guar gum was hydrolyzed using cellulase from Aspergillus niger at 5.6 pH and 50°C temperature. Hydrolyzed guar gum sample was characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, dilute solution viscometry and rotational viscometry. Viscometry analysis of native guar gum showed a molecular weight of 889742.06, whereas, after enzymatic hydrolysis, the resultant product had a molecular weight of 7936.5. IR spectral analysis suggests that after enzymatic hydrolysis of guar gum there was no major transformation of functional group. Thermal analysis revealed no major change in thermal behavior of hydrolyzed guar gum. It was shown that partial hydrolysis of guar gum could be achieved by inexpensive and food grade cellulase (Aspergillus niger) having commercial importance and utilization as a functional soluble dietary fiber for food industry. Copyright © 2012 Elsevier B.V. All rights reserved.

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

Rodriguez, Mark A.; Coker, Eric Nicholas; Griego, James J. M.

High-temperature X-ray diffraction with concurrent gas chromatography (GC) was used to study cobalt disulfide cathode pellets disassembled from thermal batteries. When CoS 2 cathode materials were analyzed in an air environment, oxidation of the K(Br, Cl) salt phase in the cathode led to the formation of K 2SO 4 that subsequently reacted with the pyrite-type CoS 2 phase leading to cathode decomposition between ~260 and 450 °C. Here, independent thermal analysis experiments, i.e. simultaneous thermogravimetric analysis/differential scanning calorimetry/mass spectrometry (MS), augmented the diffraction results and support the overall picture of CoS 2 decomposition. Both gas analysis measurements (i.e. GC andmore » MS) from the independent experiments confirmed the formation of SO 2 off-gas species during breakdown of the CoS 2. In contrast, characterization of the same cathode material under inert conditions showed the presence of CoS 2 throughout the entire temperature range of analysis.« less

Polarization-resolved second-harmonic generation microscopy as a method to visualize protein-crystal domains

PubMed Central

DeWalt, Emma L.; Begue, Victoria J.; Ronau, Judith A.; Sullivan, Shane Z.; Das, Chittaranjan; Simpson, Garth J.

2013-01-01

Polarization-resolved second-harmonic generation (PR-SHG) microscopy is described and applied to identify the presence of multiple crystallographic domains within protein-crystal conglomerates, which was confirmed by synchrotron X-ray diffraction. Principal component analysis (PCA) of PR-SHG images resulted in principal component 2 (PC2) images with areas of contrasting negative and positive values for conglomerated crystals and PC2 images exhibiting uniformly positive or uniformly negative values for single crystals. Qualitative assessment of PC2 images allowed the identification of domains of different internal ordering within protein-crystal samples as well as differentiation between multi-domain conglomerated crystals and single crystals. PR-SHG assessments of crystalline domains were in good agreement with spatially resolved synchrotron X-ray diffraction measurements. These results have implications for improving the productive throughput of protein structure determination through early identification of multi-domain crystals. PMID:23275165

Presence and dehydration of ikaite, calcium carbonate hexahydrate, in frozen shrimp shell.

PubMed

Mikkelsen, A; Andersen, A B; Engelsen, S B; Hansen, H C; Larsen, O; Skibsted, L H

1999-03-01

Ikaite, calcium carbonate hexahydrate, has by means of X-ray diffraction analyses of frozen samples been identified as the mineral component of the white spots formed in the shell of frozen shrimp during storage. When the shrimp thaw and the shell material is dried and kept at room temperature, ikaite rapidly transforms into a mixture of anhydrous calcium carbonate forms. X-ray diffraction analyses and Raman spectra of synthetic ikaite as well as the dehydration product confirm the assignments, and the rate constant for dehydration is approximately 7 x 10(-)(4) s(-)(1) at ambient temperature. Differential scanning calorimetry showed that dehydration of synthetic ikaite is an entropy-driven, athermal process and confirms that a single first-order reaction is rate-determining. Ikaite is found to be stable in aqueous solution at temperatures below 5 degrees C and in the shell of frozen shrimps but decomposes on thawing to form anhydrous calcium carbonates.

Fixed target matrix for femtosecond time-resolved and in situ serial micro-crystallography

PubMed Central

Mueller, C.; Marx, A.; Epp, S. W.; Zhong, Y.; Kuo, A.; Balo, A. R.; Soman, J.; Schotte, F.; Lemke, H. T.; Owen, R. L.; Pai, E. F.; Pearson, A. R.; Olson, J. S.; Anfinrud, P. A.; Ernst, O. P.; Dwayne Miller, R. J.

2015-01-01

We present a crystallography chip enabling in situ room temperature crystallography at microfocus synchrotron beamlines and X-ray free-electron laser (X-FEL) sources. Compared to other in situ approaches, we observe extremely low background and high diffraction data quality. The chip design is robust and allows fast and efficient loading of thousands of small crystals. The ability to load a large number of protein crystals, at room temperature and with high efficiency, into prescribed positions enables high throughput automated serial crystallography with microfocus synchrotron beamlines. In addition, we demonstrate the application of this chip for femtosecond time-resolved serial crystallography at the Linac Coherent Light Source (LCLS, Menlo Park, California, USA). The chip concept enables multiple images to be acquired from each crystal, allowing differential detection of changes in diffraction intensities in order to obtain high signal-to-noise and fully exploit the time resolution capabilities of XFELs. PMID:26798825

Structural analysis and martensitic transformation in equiatomic HfPd alloy

NASA Astrophysics Data System (ADS)

Hisada, S.; Matsuda, M.; Takashima, K.; Yamabe-Mitarai, Y.

2018-02-01

We investigated the crystal structure and the martensitic transformation in equiatomic HfPd alloy. The analysis of the crystal structure by electron diffraction and Rietveld refinement using X-ray diffraction data indicates that the space group of the martensitic phase is Cmcm, and the lattice parameters are a = 0.329 nm, b = 1.021 nm, and c = 0.438 nm. Martensitic variants are composed of the plate-like morphology of several hundred nm, and the boundaries between the variants have (021)Cmcm twin relations. This (021)Cmcm twin boundary seems to be sharp without ledge and steps. Differential scanning calorimetry measurement indicates that each martensitic transformation temperature is determined to be Ms = 819 K, Mf = 794 K, As = 928 K, and Af = 954 K. Based on the dimension change using a thermo-mechanical analyzer, the expansion and shrinkage of the sample occurred with the forward and reverse martensitic transformation, respectively.

Physical properties of new binary antiferroelectric liquid crystal mixtures

NASA Astrophysics Data System (ADS)

Fitas, Jakub; Jaworska-Gołąb, Teresa; Deptuch, Aleksandra; Tykarska, Marzena; Kurp, Katarzyna; Żurowska, Magdalena; Marzec, Monika

2018-02-01

Three newly prepared binary mixtures exhibiting chiral tilted smectic phases have been studied using differential scanning calorimetry, dielectric spectroscopy and electro-optic method, as well as X-ray diffraction. Broad temperature range of ferroelectric and antiferroelectric phases was detected in these mixtures and temperature dependence of spontaneous polarization, tilt angle and switching time were measured for all of them. It's occurred that all of the studied mixtures are orthoconic antiferroelectric liquid crystals. Based on the X-ray diffraction results, the temperature dependence of layer thickness in the paraelectric, ferroelectric and antiferroelectric phases was found. By using dielectric spectroscopy, Goldstone mode was identified in the ferroelectric phase, while antiphase fluctuations of azimuthal angle have been found in the antiferroelectric phase. Based on the results of the complementary methods, the transition temperatures were found as well as the order of the para-ferroelectric phase transition was determined as non-continuous one with critical parameter β equal to ca. 0.25.

Application of vibrational spectroscopy, thermal analyses and X-ray diffraction in the rapid evaluation of the stability in solid-state of ranitidine, famotidine and cimetidine.

PubMed

Jamrógiewicz, Marzena; Ciesielski, Aleksander

2015-03-25

This paper reports the study on applicability of Fourier transform infrared (FTIR), near-infrared (NIR) and Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) for the estimation of the chemical stability and photostability of histamine H2-receptor antagonist substances. Ranitidine hydrochloride (RAN), famotidine (FAM) and cimetidine (CIM) were tested and differences in sensitivity were measured via soft independence modeling of class analogies (Simca) model. The low values of variations for FAM and CIM and high variations obtained for RAN using FTIR and NIR techniques indicated that these methods were suitable and applicable to classify the degradation of RAN. Examined methods are recommendable in the first technological stage of drug production, and the preclinical and clinical development of pharmaceuticals or their quality control. Copyright © 2015 Elsevier B.V. All rights reserved.

Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis.

PubMed

Liu, Qun; Hendrickson, Wayne A

2017-01-01

The normal elastic X-ray scattering that depends only on electron density can be modulated by an "anomalous" component due to resonance between X-rays and electronic orbitals. Anomalous scattering thereby precisely identifies atomic species, since orbitals distinguish atomic elements, which enables the multi- and single-wavelength anomalous diffraction (MAD and SAD) methods. SAD now predominates in de novo structure determination of biological macromolecules, and we focus here on the prevailing SAD method. We describe the anomalous phasing theory and the periodic table of phasing elements that are available for SAD experiments, differentiating between those readily accessible for at-resonance experiments and those that can be effective away from an edge. We describe procedures for present-day SAD phasing experiments and we discuss optimization of anomalous signals for challenging applications. We also describe methods for using anomalous signals as molecular markers for tracing and element identification. Emerging developments and perspectives are discussed in brief.

Fixed target matrix for femtosecond time-resolved and in situ serial micro-crystallography.

PubMed

Mueller, C; Marx, A; Epp, S W; Zhong, Y; Kuo, A; Balo, A R; Soman, J; Schotte, F; Lemke, H T; Owen, R L; Pai, E F; Pearson, A R; Olson, J S; Anfinrud, P A; Ernst, O P; Dwayne Miller, R J

2015-09-01

We present a crystallography chip enabling in situ room temperature crystallography at microfocus synchrotron beamlines and X-ray free-electron laser (X-FEL) sources. Compared to other in situ approaches, we observe extremely low background and high diffraction data quality. The chip design is robust and allows fast and efficient loading of thousands of small crystals. The ability to load a large number of protein crystals, at room temperature and with high efficiency, into prescribed positions enables high throughput automated serial crystallography with microfocus synchrotron beamlines. In addition, we demonstrate the application of this chip for femtosecond time-resolved serial crystallography at the Linac Coherent Light Source (LCLS, Menlo Park, California, USA). The chip concept enables multiple images to be acquired from each crystal, allowing differential detection of changes in diffraction intensities in order to obtain high signal-to-noise and fully exploit the time resolution capabilities of XFELs.

Hydrothermal Synthesis, Crystal Structure, and Photoluminescent Properties of Li[UO2(CH3COO)3]3[Co(H2O)6

NASA Astrophysics Data System (ADS)

AlDamen, Murad A.; Juwhari, Hassan K.; Al-zuheiri, Aya M.; Alnazer, Louy A.

2017-12-01

Single crystal of Li[UO2(CH3COO)3]3[Co(H2O)6] was prepared and found to crystallize in the monoclinic crystal system in the sp. gr. C2/ c, with Z = 2, and unit cell parameters a = 22.1857(15) Å, b = 13.6477(8) Å, c = 15.6921(10) Å, β = 117.842(9)°, V = 4201.3(4) Å3. The crystal was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The single crystal X-ray diffraction analysis revealed that the crystal has a lamellar structure in which a cobalt hydrate is sandwiched within the Li[UO2(CH3COO)3]3 2- chains. Furthermore, the room temperature photoluminescence spectrum of the complex was investigated in the solid state.

Copper Refinement from Anode to Cathode and then to Wire Rod: Effects of Impurities on Recrystallization Kinetics and Wire Ductility.

PubMed

Helbert, Anne-Laure; Moya, Alice; Jil, Tomas; Andrieux, Michel; Ignat, Michel; Brisset, François; Baudin, Thierry

2015-10-01

In this paper, the traceability of copper from the anode to the cathode and then the wire rod has been studied in terms of impurity content, microstructure, texture, recrystallization kinetics, and ductility. These characterizations were obtained based on secondary ion mass spectrometry, differential scanning calorimetry (DSC), X-ray diffraction, HV hardness, and electron backscattered diffraction. It is shown that the recrystallization was delayed by the total amount of impurities. From tensile tests performed on cold drawn and subsequently annealed wires for a given time, a simplified model has been developed to link tensile elongation to the chemical composition. This model allowed quantification of the contribution of some additional elements, present in small quantity, on the recrystallization kinetics. The proposed model adjusted for the cold-drawn wires was also validated on both the cathode and wire rod used for the study of traceability.

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

Shivananda, C. S.; Rao, B. Lakshmeesha; Madhukumar, R.

In this work silk fibroin/pullulan blend films have been prepared by solution casting method. The blend films were examined for structural, and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results indicate that with the introduction of pullulan, the interaction between SF and pullulan in the blend films induced the conformation transition of SF films and amorphous phase increases with increasing pullulan ratio. The thermal properties of the blend films were improved significantly in the blend films.

Analysis of strain-induced crystallinity in neutron-irradiated amorphous PET fiber

NASA Astrophysics Data System (ADS)

Mallick, B.

2015-05-01

Polyethylene terephthalate (PET) fiber of 2.2 denier per filament has been irradiated with 4.44-MeV fast neutron beam at different low doses: 0.58-2,513.5 mGy. The variation of crystallinity because of neutron irradiation straining in PET filaments has been investigated. Study of the effects of irradiation by using X-ray diffraction and differential scanning calorimetry technique confirms the radiation-induced microstrain-dependent crystallinity of PET fiber.

Lithographically-Scribed Planar Holographic Optical CDMA Devices and Systems

DTIC Science & Technology

2007-02-15

operate with quite high refractive index contrast (order 0.5). Thin -filn filter devices are viewed as relatively low in chromatic dispersion. We have...stack consists of planar interfaces between materials of refractive index n, and n,. Let An = In2 - nil and n = (n, - n1)/2. The planar interfaces are... index ). It may be desirable to have a relatively large refractive index differential when diffractive elements are formed from cladding material at a

Polyimides with carbonyl and ether connecting groups between the aromatic rings

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Havens, Stephen J. (Inventor)

1992-01-01

New polyimides have been prepared from the reaction of aromatic dianhydrides with novel aromatic diamines containing carbonyl and ether connecting groups between the aromatic rings. Several of these polyimides are shown to be semi-crystalline as evidenced by wide angle x ray diffraction and differential scanning calorimetry. Most of the polyimides form tough solvent resistant films with high tensile properties. Several of these materials can be thermally processed to form solvent and base resistant moldings.

Shape Memory Characteristics of Rapidly Solidified Ti-37.8Cu-18.7Ni Alloy Ribbons

NASA Astrophysics Data System (ADS)

Ramos, Alana Pereira; de Castro, Walman Benicio

Amorphization and martensitic transformation (Ms) characteristics of Ti-Ni-Cu alloy ribbons prepared by melt spinning were investigated by means of differential scanning calorimetry and X-ray diffraction. In these experiments particular attention has been paid to change the wheel linear velocity from 21 to 63 m/s. Then the cooling rates of ribbons were controlled. The effect of this cooling rate and alloy composition on martensitic transformation behavior is discussed.

Nonlinear ring resonator: spatial pattern generation

NASA Astrophysics Data System (ADS)

Ivanov, Vladimir Y.; Lachinova, Svetlana L.; Irochnikov, Nikita G.

2000-03-01

We consider theoretically spatial pattern formation processes in a unidirectional ring cavity with thin layer of Kerr-type nonlinear medium. Our method is based on studying of two coupled equations. The first is a partial differential equation for temporal dynamics of phase modulation of light wave in the medium. It describes nonlinear interaction in the Kerr-type lice. The second is a free propagation equation for the intracavity field complex amplitude. It involves diffraction effects of light wave in the cavity.

Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-C x H(2 x+1)OSO3Li ( x = 12, 14, 16, 18, and 20)

NASA Astrophysics Data System (ADS)

Hirakawa, Satoru; Morimoto, Yoshiaki; Honda, Hisashi

2015-04-01

Electrical conductivity ( σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C x H (2 x+1) OSO 3Li ( x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C x H (2 x+1) OSO 3Na and n-C x H (2 x+1) OSO 3K ( x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (Δ S). For n-C 18 H 37 OSO 3Li and n-C 20 H 41 OSO 3Li salts, each melting point produced a small Δ S mp value compared with the total entropy change in the solid phases (Δ S tr1+Δ S tr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18 H 37 OSO 3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals.

Analysis of nanoparticles using photonic nanojet

NASA Astrophysics Data System (ADS)

Li, Xu; Chen, Zhigang; Siegel, Michael P.; Taflove, Allen; Backman, Vadim

2005-04-01

A photonic nanojet is a local field enhancement generated in the vicinity of a properly chosen microsphere or microcylinder illuminated by a collimated light beam. These photonic nanojets have waists smaller than the diffraction limit and propagate over several optical wavelengths without significant diffraction. We investigate the properties of photonic nanojets using rigorous solutions of Maxwell"s equations. A remarkable property we have found is that they can significantly enhance the backscattering of light by nanometer-scale particles (as small as ~1 nm) located within the jets. The enhancement factor for the backscattering intensity can be as high as five to six orders of magnitude. As a result, the observed intensity of the backscattered light from the dielectric microsphere can be substantially altered due to the presence of a nanoparticle within the light jet. Furthermore, the intensity and angular distribution of the backscattered signal is extremely sensitive to the size of the nanoparticle, which may enable differentiating particles with accuracy up to 1 nm. These properties of photonic nanojets make them an ideal tool for detecting, differentiating and sorting nanoparticles, which is of immense necessity for the field of nano-biotechnology. For example, they could yield potential novel ultramicroscopy techniques using visible light for detecting proteins, viral particles, and even single molecules; and monitoring molecular synthesis and aggregation processes of importance in many areas of biology, chemistry, material sciences, and tissue engineering.

Production of pure indinavir free base nanoparticles by a supercritical anti-solvent (SAS) method.

PubMed

Imperiale, Julieta C; Bevilacqua, Gabriela; Rosa, Paulo de Tarso Vieira E; Sosnik, Alejandro

2014-12-01

This work investigated the production of pure indinavir free base nanoparticles by a supercritical anti-solvent method to improve the drug dissolution in intestine-like medium. To increase the dissolution of the drug by means of a supercritical fluid processing method. Acetone was used as solvent and supercritical CO2 as antisolvent. Products were characterized by dynamic light scattering (size, size distribution), scanning electron microscopy (morphology), differential scanning calorimetry (thermal behaviour) and X-rays diffraction (crystallinity). Processed indinavir resulted in particles of significantly smaller size than the original drug. Particles showed at least one dimension at the nanometer scale with needle or rod-like morphology. Results of X-rays powder diffraction suggested the formation of a mixture of polymorphs. Differential scanning calorimetry analysis showed a main melting endotherm at 152 °C. Less prominent transitions due to the presence of small amounts of bound water (in the raw drug) or an unstable polymorph (in processed IDV) were also visible. Finally, drug particle size reduction significantly increased the dissolution rate with respect to the raw drug. Conversely, the slight increase of the intrinsic solubility of the nanoparticles was not significant. A supercritical anti-solvent method enabled the nanonization of indinavir free base in one single step with high yield. The processing led to faster dissolution that would improve the oral bioavailability of the drug.

Embryonic stem cells in scaffold-free three-dimensional cell culture: osteogenic differentiation and bone generation.

PubMed

Handschel, Jörg; Naujoks, Christian; Depprich, Rita; Lammers, Lydia; Kübler, Norbert; Meyer, Ulrich; Wiesmann, Hans-Peter

2011-07-14

Extracorporeal formation of mineralized bone-like tissue is still an unsolved challenge in tissue engineering. Embryonic stem cells may open up new therapeutic options for the future and should be an interesting model for the analysis of fetal organogenesis. Here we describe a technique for culturing embryonic stem cells (ESCs) in the absence of artificial scaffolds which generated mineralized miromasses. Embryonic stem cells were harvested and osteogenic differentiation was stimulated by the addition of dexamethasone, ascorbic acid, and ß-glycerolphosphate (DAG). After three days of cultivation microspheres were formed. These spherical three-dimensional cell units showed a peripheral zone consisting of densely packed cell layers surrounded by minerals that were embedded in the extracellular matrix. Alizarine red staining confirmed evidence of mineralization after 10 days of DAG stimulation in the stimulated but not in the control group. Transmission electron microscopy demonstrated scorching crystallites and collagenous fibrils as early indication of bone formation. These extracellular structures resembled hydroxyl apatite-like crystals as demonstrated by distinct diffraction patterns using electron diffraction analysis. The micromass culture technique is an appropriate model to form three-dimensional bone-like micro-units without the need for an underlying scaffold. Further studies will have to show whether the technique is applicable also to pluripotent stem cells of different origin. © 2011 Handschel et al; licensee BioMed Central Ltd.

Physical metallurgy of metastable Bcc lanthanide-magnesium alloys for R = La, Gd, and Dy

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

Herchenroeder, J.W.; Manfrinetti, P.; Gschneidner, K.A. Jr.

1989-09-01

Bcc La-Mg, Gd-Mg, and Dy-Mg alloys have been prepared by an ice water/acetone quench from liquid melts. Single-phase alloys could be retained in a window around the eutectoid composition: 13 to 22 at. pct Mg, 23.6 to 29 at. pct Mg, and 27 to 29 at. pct Mg for La, Gd, and Dy alloys, respectively. At the center of the windows, x-ray diffraction peaks are extremely sharp as in equilibrium bcc structures; however, as alloy composition is moved away from the eutectoid, line broadening is observed. Reversion of the bcc phase to the equilibrium microstructure for R-Mg alloys (R =more » La, Gd, or Dy) has been characterized by differential thermal analysis (DTA) or differential scanning calorimetry (DSC) and isothermal annealing. La-Mg alloys revert directly to {alpha}La (dhcp) + LaMg at about 350{degrees}C when heated at 10{degrees}C/min. In contrast, the Gd and Dy alloys revert by a two-step process: first, a transition to an intermediate distorted hcp phase between 300{degrees}C and 400{degrees}C, and, second, the relaxation of this phase to {alpha}R (hcp) + RMg at about 490{degrees}C when heated at 10{degrees}C/min. Isothermal annealing and high temperature x-ray diffraction confirm the nature of these reactions.« less

Optimization of sustained release aceclofenac microspheres using response surface methodology.

PubMed

Deshmukh, Rameshwar K; Naik, Jitendra B

2015-03-01

Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14±0.015% to 85.34±0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12h. The optimized microspheres formulation showed E.E. of 84.87±0.005 with small error value (1.39). The low magnitudes of error and the significant value of R(2) in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. Copyright © 2014 Elsevier B.V. All rights reserved.

A comparative study of diffraction of shallow-water waves by high-level IGN and GN equations

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

Zhao, B.B.; Ertekin, R.C.; College of Shipbuilding Engineering, Harbin Engineering University, 150001 Harbin

2015-02-15

This work is on the nonlinear diffraction analysis of shallow-water waves, impinging on submerged obstacles, by two related theories, namely the classical Green–Naghdi (GN) equations and the Irrotational Green–Naghdi (IGN) equations, both sets of equations being at high levels and derived for incompressible and inviscid flows. Recently, the high-level Green–Naghdi equations have been applied to some wave transformation problems. The high-level IGN equations have also been used in the last decade to study certain wave propagation problems. However, past works on these theories used different numerical methods to solve these nonlinear and unsteady sets of differential equations and at differentmore » levels. Moreover, different physical problems have been solved in the past. Therefore, it has not been possible to understand the differences produced by these two sets of theories and their range of applicability so far. We are thus motivated to make a direct comparison of the results produced by these theories by use of the same numerical method to solve physically the same wave diffraction problems. We focus on comparing these two theories by using similar codes; only the equations used are different but other parts of the codes, such as the wave-maker, damping zone, discretion method, matrix solver, etc., are exactly the same. This way, we eliminate many potential sources of differences that could be produced by the solution of different equations. The physical problems include the presence of various submerged obstacles that can be used for example as breakwaters or to represent the continental shelf. A numerical wave tank is created by placing a wavemaker on one end and a wave absorbing beach on the other. The nonlinear and unsteady sets of differential equations are solved by the finite-difference method. The results are compared with different equations as well as with the available experimental data.« less

Introducing a non-pixelated and fast centre of mass detector for differential phase contrast microscopy.

PubMed

Schwarzhuber, Felix; Melzl, Peter; Pöllath, Simon; Zweck, Josef

2018-06-10

With the advent of probe corrected STEM machines it became possible to probe specimens on a scale of less than 50 pm resolution. This opens completely new horizons for research, as it is e.g. possible to probe the electrostatic fields between individual rows of atoms, using differential phase contrast (DPC). However, in contrast to conventional DPC, where one deals with extended fields which can be assumed constant across the electron probe, this is not possible for sub-atomic probes in DPC. For the latter case it was shown [1,2], that the strongly inhomogeneous field distribution within the probe diameter, which usually is caused by the nuclear potentials of an atomic column, leads to a complicated intensity redistribution within the diffraction disk. The task is then to determine the intensity weighted centre of the diffraction disk pattern (frequently also called centre of mass, COM), which is proportional to the average lateral momentum gained by the average electron, transmitted through the probe diameter. In first reported measurements, the determination of this COM was achieved using a pixelated detector in combination with a software-based evaluation of the COM. This suffers from two disadvantages: first, the nowadays available pixelated detectors are still not very fast (approximately 1000 fps) and quite expensive, and second, the amount of data to be processed after acquisition is comparatively huge. In this paper we report on an alternative to a pixelated detector, which is able to directly deliver the COM of a diffraction disk's intensity distribution with frequencies up to 200 kHz. We present measurements on the sensitivity of this detector as well as first results from DPC imaging. From these results we expect the detector also to serve well in sub-atomic DPC field sensing, possibly replacing today's segmented or pixelated detectors. Copyright © 2018 Elsevier B.V. All rights reserved.

A comparative study of diffraction of shallow-water waves by high-level IGN and GN equations

NASA Astrophysics Data System (ADS)

Zhao, B. B.; Ertekin, R. C.; Duan, W. Y.

2015-02-01

This work is on the nonlinear diffraction analysis of shallow-water waves, impinging on submerged obstacles, by two related theories, namely the classical Green-Naghdi (GN) equations and the Irrotational Green-Naghdi (IGN) equations, both sets of equations being at high levels and derived for incompressible and inviscid flows. Recently, the high-level Green-Naghdi equations have been applied to some wave transformation problems. The high-level IGN equations have also been used in the last decade to study certain wave propagation problems. However, past works on these theories used different numerical methods to solve these nonlinear and unsteady sets of differential equations and at different levels. Moreover, different physical problems have been solved in the past. Therefore, it has not been possible to understand the differences produced by these two sets of theories and their range of applicability so far. We are thus motivated to make a direct comparison of the results produced by these theories by use of the same numerical method to solve physically the same wave diffraction problems. We focus on comparing these two theories by using similar codes; only the equations used are different but other parts of the codes, such as the wave-maker, damping zone, discretion method, matrix solver, etc., are exactly the same. This way, we eliminate many potential sources of differences that could be produced by the solution of different equations. The physical problems include the presence of various submerged obstacles that can be used for example as breakwaters or to represent the continental shelf. A numerical wave tank is created by placing a wavemaker on one end and a wave absorbing beach on the other. The nonlinear and unsteady sets of differential equations are solved by the finite-difference method. The results are compared with different equations as well as with the available experimental data.

A study of degradation resistance and cytocompatibility of super-hydrophobic coating on magnesium.

PubMed

Zhang, Yufen; Feyerabend, Frank; Tang, Shawei; Hu, Jin; Lu, Xiaopeng; Blawert, Carsten; Lin, Tiegui

2017-09-01

Calcium stearate based super-hydrophobic coating was deposited on plasma electrolytic oxidation (PEO) pre-treated magnesium substrate. The pre-treated magnesium and super-hydrophobic coating covered sample were characterized by scanning electron microscopy, X-ray diffraction and electrochemical corrosion measurements. The cytocompatibility and degradation resistance of magnesium, pre-treated magnesium and super-hydrophobic coating were analysed in terms of cell adhesion and osteoblast differentiation. The results indicate that the calcium stearate top coating shows super-hydrophobicity and that the surface is composed of micro/nanostructure. The super-hydrophobic coating covered sample shows higher barrier properties compared with the PEO pre-treated magnesium and bare magnesium. Human osteoblast proliferation, but not differentiation is enhanced by the PEO coating. Contrary, the super-hydrophobic coating reduces proliferation, but enhances differentiation of osteoblast, observable by the formation of hydroxyapatite. The combination of corrosion protection and cell reaction indicates that this system could be interesting for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Asymptotic Poincare lemma and its applications

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

Ziolkowski, R.W.; Deschamps, G.A.

1984-05-01

An asymptotic version of Poincare's lemma is defined and solutions are obtained with the calculus of exterior differential forms. They are used to construct the asymptotic approximations of multidimensional oscillatory integrals whose forms are commonly encountered, for example, in electromagnetic problems. In particular, the boundary and stationary point evaluations of these integrals are considered. The former is applied to the Kirchhoff representation of a scalar field diffracted through an aperture and simply recovers the Maggi-Rubinowicz-Miyamoto-Wolf results. Asymptotic approximations in the presence of other (standard) critical points are also discussed. Techniques developed for the asymptotic Poincare lemma are used to generatemore » a general representation of the Leray form. All of the (differential form) expressions presented are generalizations of known (vector calculus) results. 14 references, 4 figures.« less

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

Madhukumar, R.; Asha, S.; Rao, B. Lakshmeesha

The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

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

Xie, Miao; Mohammadi, Reza; Turner, Christopher L.

In this paper, we explore the hardening mechanisms in WB4-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under nonhydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB 4 solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

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

Xie, Miao; Turner, Christopher L.; Mohammadi, Reza

In this work, we explore the hardening mechanisms in WB{sub 4}-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under non-hydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB{sub 4} solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

Ion dynamics in nanocrystalline LiMnPO{sub 4} synthesised by novel template free hydrothermal approach

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

Vijayan, Lakshmi, E-mail: lakshmivijayan@gmail.com; Cheruku, Rajesh; Govindaraj, G.

A dense core rectangular shaped nanocrystalline LiMnPO{sub 4} material was synthesized by template free sucrose assisted hydrothermal synthesis. The material possess orthorhombic crystal structure with Pnma, space group having four formula units. The structural characterization was accomplished through X-ray diffraction, thermo gravimetry/differential thermal analysis. Morphology was identified by the SEM, VSM was used to verify the magnetic behavior of the material and electrical characterization was done through impedance spectroscopy and the results were reported.

Diffraction of Electromagnetic Waves on a Waveguide Joint

NASA Astrophysics Data System (ADS)

Malykh, Mikhail; Sevastianov, Leonid; Tyutyunnik, Anastasiya; Nikolaev, Nikolai

2018-02-01

In general, the investigation of the electromagnetic field in an inhomogeneous waveguide doesn't reduce to the study of two independent boundary value problems for the Helmholtz equation. We show how to rewrite the Helmholtz equations in the "Hamiltonian form" to express the connection between these two problems explicitly. The problem of finding monochromatic waves in an arbitrary waveguide is reduced to an infinite system of ordinary differential equations in a properly constructed Hilbert space. The calculations are performed in the computer algebra system Sage.

Synthesis of samarium doped gadolinium oxide nanorods, its spectroscopic and physical properties

NASA Astrophysics Data System (ADS)

Boopathi, G.; Gokul Raj, S.; Ramesh Kumar, G.; Mohan, R.; Mohan, S.

2018-06-01

One-dimensional samarium doped gadolinium oxide [Sm:Gd2O3] nanorods have been synthesized successfully through co-precipitation technique in aqueous solution. The as-synthesized and calcined products were characterized by using powder X-ray diffraction pattern, Fourier transform Raman spectroscopy, thermogravimetric/differential thermal analysis, scanning electron microscopy with energy-dispersive X-ray analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, Ultraviolet-Visible spectrometry, photoluminescence spectrophotometer and X-ray photoelectron spectroscopy techniques. The obtained results are discussed in detailed manner.

Influence of electron irradiation on the structural and thermal properties of silk fibroin films

NASA Astrophysics Data System (ADS)

Asha, S.; Sangappa, Sanjeev, Ganesh

2015-06-01

Radiation-induced changes in Bombyx mori silk fibroin (SF) films under electron irradiation were investigated and correlated with dose. SF films were irradiated in air at room temperature using 8 MeV electron beam in the range 0-150 kGy. Various properties of the irradiated SF films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Electron irradiation was found to induce changes in the physical and thermal properties, depending on the radiation dose.

Projection of the Liquidus Surface of the Co - Sn - Bi System

NASA Astrophysics Data System (ADS)

Abilov, Ch. I.; Allazov, M. R.; Sadygova, S. G.

2016-11-01

The crystallization behavior of phases in alloys of the Co - Sn - Bi system is studied by the methods of differential thermal (DTA), x-ray phase (XRP) and x-ray diffraction (XRD) analyses and hardness measurement. The projection of the liquidus surface is plotted. The boundaries of layering, the development of the monovariant processes, and the coordinates of the nonvariant equilibrium compositions are determined. Compositions of (Co3Sn2)1 - x Bi x solid solutions suitable for the production of antifriction materials are suggested.

Cu sbnd Al sbnd Fe layered double hydroxides with CO32- and anionic surfactants with different alkyl chains in the interlayer

NASA Astrophysics Data System (ADS)

Trujillano, Raquel; Holgado, María Jesús; González, José Luis; Rives, Vicente

2005-08-01

Layered double hydroxides (LDHs), with the hydrotalcite-like structure containing Cu(II), Al(III) and Fe(III) in the layers, and different alkyl sulfonates in the interlayer, have been prepared and characterized by powder X-ray diffraction, FT-IR spectroscopy, differential thermal analysis and thermogravimetric analysis. Pure crystalline phases have been obtained in all cases. Upon heating, combustion of the organic chain takes place at lower temperature than the corresponding sodium salts.

The practical Pomeron for high energy proton collimation

NASA Astrophysics Data System (ADS)

Appleby, R. B.; Barlow, R. J.; Molson, J. G.; Serluca, M.; Toader, A.

2016-10-01

We present a model which describes proton scattering data from ISR to Tevatron energies, and which can be applied to collimation in high energy accelerators, such as the LHC and FCC. Collimators remove beam halo particles, so that they do not impinge on vulnerable regions of the machine, such as the superconducting magnets and the experimental areas. In simulating the effect of the collimator jaws it is crucial to model the scattering of protons at small momentum transfer t, as these protons can subsequently survive several turns of the ring before being lost. At high energies these soft processes are well described by Pomeron exchange models. We study the behaviour of elastic and single-diffractive dissociation cross sections over a wide range of energy, and show that the model can be used as a global description of the wide variety of high energy elastic and diffractive data presently available. In particular it models low mass diffraction dissociation, where a rich resonance structure is present, and thus predicts the differential and integrated cross sections in the kinematical range appropriate to the LHC. We incorporate the physics of this model into the beam tracking code MERLIN and use it to simulate the resulting loss maps of the beam halo lost in the collimators in the LHC.

Growth, structural, spectral, mechanical, thermal and dielectric characterization of phosphoric acid admixtured L-alanine (PLA) single crystals.

PubMed

Rose, A S J Lucia; Selvarajan, P; Perumal, S

2011-10-15

Phosphoric acid admixtured L-alanine (PLA) single crystals were grown successfully by solution method with slow evaporation technique at room temperature. Crystals of size 18 mm×12 mm×8 mm have been obtained in 28 days. The grown crystals were colorless and transparent. The solubility of the grown samples has been found out at various temperatures. The lattice parameters of the grown crystals were determined by X-ray diffraction technique. The reflection planes of the sample were confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. Fourier transform infrared (FTIR) studies were used to confirm the presence of various functional groups in the crystals. UV-visible transmittance spectrum was recorded to study the optical transparency of grown crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz-Perry powder technique and a study of its second harmonic generation efficiency in comparison with potassium dihydrogen phosphate (KDP) has been made. The mechanical strength of the crystal was estimated by Vickers hardness test. The grown crystals were subjected to thermo gravimetric and differential thermal analysis (TG/DTA). The dielectric behavior of the sample was also studied. Copyright © 2011 Elsevier B.V. All rights reserved.

Coherent diffractive photoproduction of ρ0 mesons on gold nuclei at 200 GeV/nucleon-pair at the Relativistic Heavy Ion Collider

NASA Astrophysics Data System (ADS)

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Klein, S. R.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

2017-11-01

The STAR Collaboration reports on the photoproduction of π+π- pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly real photon emitted by one ion scatters from the other ion. We fit the π+π- invariant-mass spectrum with a combination of ρ0 and ω resonances and a direct π+π- continuum. This is the first observation of the ω in ultraperipheral collisions, and the first measurement of ρ -ω interference at energies where photoproduction is dominated by Pomeron exchange. The ω amplitude is consistent with the measured γ p →ω p cross section, a classical Glauber calculation, and the ω →π+π- branching ratio. The ω phase angle is similar to that observed at much lower energies, showing that the ρ -ω phase difference does not depend significantly on photon energy. The ρ0 differential cross section d σ /d t exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with two minima visible. The positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.

Integrated high-order surface diffraction gratings for diode lasers

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

Zolotarev, V V; Leshko, A Yu; Pikhtin, N A

2015-12-31

High-order surface diffraction gratings acting as a distributed Bragg reflector (DBR) in mesa stripe semiconductor lasers (λ = 1030 nm) have been studied theoretically and experimentally. Higher order interfering radiation modes (IRMs), which propagate off the plane of the waveguide, have been shown to have a crucial effect on the reflection and transmission spectra of the DBR. The decrease in the reflectivity of the DBR in response to the increase in the diffraction efficiency of these modes may reach 80% and more. According to theoretical analysis results, the intensity of the higher order IRMs is determined by the geometry ofmore » the DBR groove profile. Experimental data demonstrate that the noncavity modes are responsible for parasitic light leakage losses in the laser cavity. It has been shown that, in the case of nonoptimal geometry of the grating groove profile, the overall external differential quantum efficiency of the parasitic laser emission may exceed 45%, which is more than half of the laser output power. The optimal geometry of the DBR groove profile is trapezoidal, with the smallest possible lower base. Experimental evidence has been presented that this geometry considerably reduces the power of the higher order IRMs and minimises the parasitic light leakage loss. (lasers)« less

Design of a panoramic long-wave infrared athermal system

NASA Astrophysics Data System (ADS)

Yao, Yuan; Geng, Anbing; Bai, Jian; Wang, Haitao; Guo, Jie; Xiong, Tao; Luo, Yujie; Huang, Zhi; Hou, Xiyun

2016-12-01

A panoramic long-wave infrared athermal system is introduced in this paper. The proposed system includes a panoramic annular lens (PAL) block providing a stereo field of view of (30 deg - 100 deg) × 360 deg without the need to move its components. Moreover, to ensure the imaging quality at different temperatures, a refractive/diffractive hybrid lens is introduced to achieve optical passive athermalization. The system operates in a spectral band between 8 and 12 μm, with a total length of 175 mm and a focal length of 3.4 mm. To get a bright and clear image, the aperture of the system was set to f/1.15. The introduction of aspherical surface and even-order diffractive surface not only eliminates the differential thermal but also makes the structure simple and lightweight and improves the image quality. The results show that the modulation transfer function below 20 lp/mm of the system is above 0.2 at each temperature ranging from -20°C to +60°C, which is close to the diffraction limit. The system is suitable to be applied in an uncooled infrared focal plane array detector and will serve as a static alert system. It has a number of pixels of 640×480, and the pixel size is 25 μm.

Synthesis, characterization and dissolution of three pharmaceutical cocrystals based on deferiprone

NASA Astrophysics Data System (ADS)

Zhang, Xiaoming; Tian, Yuyang; Jia, Jiangtao; Zhang, Tingting; Zhu, Guangshan

2016-03-01

In this paper we present three new cocrystals based on deferiprone which is the first oral medicine as iron chelator. Solitary deferiprone possesses some known problems due to its good solubility and frequent dosing side effects. For these three novel co crystals, deferiprone is the active pharmaceutical ingredient (API), p-hydroxybenzoic acid (1, C7H9NO2·C7H6O3), 2, 5-dihydroxybenzoic acid (2, C7H9NO2·C7H6O4) and maleic acid (3, C7H9NO2·C4H4O4) are used as cocrystal formers (CCFs), respectively. Their structures were characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD) analysis, thermogravimetric analyses (TGA), differential thermal analysis (DTA), elemental analysis (EA) and infrared spectral analysis (IR). Single crystal X-ray diffraction demonstrates that all three cocrystals (1-3) possess strong hydrogen-bondings assembled through hydroxyl of API and carboxylic acids of CCFs. The PXRD results indicate their high purity of as-synthesized samples. TGA, DTA, EA, IR and dissolution study of API and cocrystals were also measured and discussed, respectively. The results suggest that the cocrystals exhibit low dissolution rates comparing with solitary deferiprone, which is very advantageous for the oral medicine with frequent dosing side effects.

Effect of gamma-irradiation on thermal decomposition kinetics, X-ray diffraction pattern and spectral properties of tris(1,2-diaminoethane)nickel(II)sulphate

NASA Astrophysics Data System (ADS)

Jayashri, T. A.; Krishnan, G.; Rema Rani, N.

2014-12-01

Tris(1,2-diaminoethane)nickel(II)sulphate was prepared, and characterised by various chemical and spectral techniques. The sample was irradiated with 60Co gamma rays for varying doses. Sulphite ion and ammonia were detected and estimated in the irradiated samples. Non-isothermal decomposition kinetics, X-ray diffraction pattern, Fourier transform infrared spectroscopy, electronic, fast atom bombardment mass spectra, and surface morphology of the complex were studied before and after irradiation. Kinetic parameters were evaluated by integral, differential, and approximation methods. Irradiation enhanced thermal decomposition, lowering thermal and kinetic parameters. The mechanism of decomposition is controlled by R3 function. From X-ray diffraction studies, change in lattice parameters and subsequent changes in unit cell volume and average crystallite size were observed. Both unirradiated and irradiated samples of the complex belong to trigonal crystal system. Decrease in the intensity of the peaks was observed in the infrared spectra of irradiated samples. Electronic spectral studies revealed that the M-L interaction is unaffected by irradiation. Mass spectral studies showed that the fragmentation patterns of the unirradiated and irradiated samples are similar. The additional fragment with m/z 256 found in the irradiated sample is attributed to S8+. Surface morphology of the complex changed upon irradiation.

Graphene Oxide–Silver Nanoparticles Nanocomposite Stimulates Differentiation in Human Neuroblastoma Cancer Cells (SH-SY5Y)

PubMed Central

Gurunathan, Sangiliyandi

2017-01-01

Recently, graphene and graphene related nanocomposite receive much attention due to high surface-to-volume ratio, and unique physiochemical and biological properties. The combination of metallic nanoparticles with graphene-based materials offers a promising method to fabricate novel graphene–silver hybrid nanomaterials with unique functions in biomedical nanotechnology, and nanomedicine. Therefore, this study was designed to prepare graphene oxide (GO) silver nanoparticles (AgNPs) nanocomposite (GO-AgNPs) containing two different nanomaterials in single platform with distinctive properties using luciferin as reducing agents. In addition, we investigated the effect of GO-AgNPs on differentiation in SH-SY5Y cells. The synthesized GO-AgNPs were characterized by ultraviolet-visible absorption spectroscopy (UV-vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The differentiation was confirmed by series of cellular and biochemical assays. The AgNPs were distributed uniformly on the surface of graphene oxide with an average size of 25 nm. As prepared GO-AgNPOs induces differentiation by increasing the expression of neuronal differentiation markers and decreasing the expression of stem cell markers. The results indicated that the redox biology involved the expression of various signaling molecules, which play an important role in differentiation. This study suggests that GO-AgNP nanocomposite could stimulate differentiation of SH-SY5Y cells. Furthermore, understanding the mechanisms of differentiation of neuroblastoma cells could provide new strategies for cancer and stem cell therapies. Therefore, these studies suggest that GO-AgNPs could target specific chemotherapy-resistant cells within a tumor. PMID:29182571

Probing ionospheric structures using the LOFAR radio telescope

NASA Astrophysics Data System (ADS)

Mevius, M.; van der Tol, S.; Pandey, V. N.; Vedantham, H. K.; Brentjens, M. A.; de Bruyn, A. G.; Abdalla, F. B.; Asad, K. M. B.; Bregman, J. D.; Brouw, W. N.; Bus, S.; Chapman, E.; Ciardi, B.; Fernandez, E. R.; Ghosh, A.; Harker, G.; Iliev, I. T.; Jelić, V.; Kazemi, S.; Koopmans, L. V. E.; Noordam, J. E.; Offringa, A. R.; Patil, A. H.; van Weeren, R. J.; Wijnholds, S.; Yatawatta, S.; Zaroubi, S.

2016-07-01

LOFAR is the LOw-Frequency Radio interferometer ARray located at midlatitude (52°53'N). Here we present results on ionospheric structures derived from 29 LOFAR nighttime observations during the winters of 2012/2013 and 2013/2014. We show that LOFAR is able to determine differential ionospheric total electron content values with an accuracy better than 0.001 total electron content unit = 1016m-2 over distances ranging between 1 and 100 km. For all observations the power law behavior of the phase structure function is confirmed over a long range of baseline lengths, between 1 and 80 km, with a slope that is, in general, larger than the 5/3 expected for pure Kolmogorov turbulence. The measured average slope is 1.89 with a one standard deviation spread of 0.1. The diffractive scale, i.e., the length scale where the phase variance is 1rad2, is shown to be an easily obtained single number that represents the ionospheric quality of a radio interferometric observation. A small diffractive scale is equivalent to high phase variability over the field of view as well as a short time coherence of the signal, which limits calibration and imaging quality. For the studied observations the diffractive scales at 150 MHz vary between 3.5 and 30 km. A diffractive scale above 5 km, pertinent to about 90% of the observations, is considered sufficient for the high dynamic range imaging needed for the LOFAR epoch of reionization project. For most nights the ionospheric irregularities were anisotropic, with the structures being aligned with the Earth magnetic field in about 60% of the observations.

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.

Assembly and property research on seven 0D–3D complexes derived from imidazole dicarboxylate and 1,2-bi(pyridin-4-yl)ethene

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

Mu, Bao; Li, Qian; Lv, Lei

2015-03-15

The hydrothermal reaction of transition metals, 1H-imidazole-4,5-dicarboxylic acid (H{sub 3}ImDC) and 1,2-bi(pyridin-4-yl)ethene (bpe) affords a series of new complexes, namely, [Mn(HImDC)(bpe)(H{sub 2}O)] (1), [M(H{sub 2}ImDC){sub 2}(H{sub 2}O){sub 2}]·(bpe) (M=Fe(2), Co(3), Zn(4), Cd(6)), [Zn{sub 3}(ImDC){sub 2}(bpe)(H{sub 2}O)]·3H{sub 2}O (5) and [Cd(H{sub 2}ImDC)(bpe)] (7), which are characterized by elemental analyses, IR, TG, XRPD and single crystal X-ray diffraction. Complex 1 exhibits a one dimensional (1D) zigzag chain with two types of irregular rings, and the 1D chains are linked to form a three dimensional (3D) supramolecular framework by the hydrogen bonding interactions (O–H∙∙∙O and O–H∙∙∙N). Complexes 2–4 and 6 are isomorphous, andmore » they display the mononuclear structures. In these complexes, the O–H∙∙∙O and O–H∙∙∙N hydrogen bonds play an important role in sustaining the whole 3D supramolecular frameworks. Complex 5 shows a (3,3)-connected 3D framework with (10{sup 3}) topology, and the lattice water molecules as guest molecules exist in the 3D framework. Complex 7 is a wave-like two dimensional (2D) structure, in which the adjacent 1D chains point at the opposite directions. Moreover, the fluorescent properties of complexes 1–7 and the magnetic property of 1 have been investigated. The water vapor adsorption for complex 5 has been researched at 298 K. - Graphical abstract: Seven new complexes based on different structural characteristics have been hydrothermally synthesized by the mixed ligands. The fluorescent properties, the magnetic property and the water vapor adsorption have been investigated. - Highlights: • The semi-rigid ligand with C=C bonds and imidazole dicarboxylates with some advantages have been used. • A series of new complexes with different structural characteristics have been discussed in detail. • The fluorescent properties, the magnetic property and the water vapor adsorption have been investigated.« less

Weathering of ordinary chondrites from the Atacama Desert, Chile, by Mössbauer spectroscopy and synchrotron radiation X-ray diffraction

NASA Astrophysics Data System (ADS)

Munayco, Pablo; Munayco, Jimmy; Avillez, Roberto R.; Valenzuela, Millarca; Rochette, Pierre; Gattacceca, JéRôMe; Scorzelli, Rosa B.

2013-03-01

Some terrestrial areas have climatic and geomorphologic features that favor the preservation, and therefore, accumulation of meteorites. The Atacama Desert in Chile is among the most important of such areas, known as DCA. This desert is the driest on Earth, one of the most arid, uninhabitable localities with semiarid, arid, and hyper-arid conditions. The meteorites studied here were collected from within the DCA of San Juan and Pampa de Mejillones, located, respectively, in the Central Depression and the Coastal Range of the Atacama Desert. 57Fe Mössbauer spectroscopy was used for quantitative analysis of the degree of weathering of the meteorites, through the determination of the proportions of the various Fe-bearing phases and in particular the amount of oxidized iron in terrestrial alteration products. The abundance of ferric ions in weathered chondrites can be related to specific precursor compositions and to the level of terrestrial weathering. The aim of the study was the identification, quantification, and differentiation of the weathering products in the ordinary chondrites found in the San Juan and the Pampa de Mejillones areas of the Atacama Desert. The 57Fe Mössbauer spectroscopy study was complemented by synchrotron radiation X-ray diffraction and magnetic susceptibility measurements. The results allow a clear differentiation of the rate of weathering in meteorite samples collected from the San Juan versus the Pampa de Mejillones areas of the Atacama Desert.

Modification of Optical, Structural and Dielectric Properties of MeV Ions Irradiated PS/Cu Nanocomposites.

PubMed

Gavade, Chaitali; Singh, N L; Khanna, P K; Shah, Sunil

2015-12-01

In order to study structural, thermal, optical and dielectric behaviors of composites, the films of Cu/polystyrene nanocomposites were synthesized at different concentrations of Cu-nanoparticles. These polymer nanocomposites were irradiated with carbon (85 MeV) and silicon (120 MeV) ions at different fluences. The samples were characterized using different techniques viz: X-ray diffraction, UV-visible spectroscopy, differential scanning calorimetry, and impedance gain phase analyzer. A noticeable increase in the intensity of X-ray diffraction peaks was observed after irradiation with 120 MeV Si-ions, which may be attributed to radiation-induced cross-linking in polymer. Optical properties like band gap was estimated for pure polymer and nanocomposite films from their optical absorption spectra in the wavelength region 200-800 nm. It was found that the band gap value shifted to lower energy (from 4.38 eV to 3.40 eV) on doping with silver nanoparticles and also upon irradiation. Differential scanning calorimetry analysis revealed an increase in the glass transition temperature upon irradiation, which may be attributed to cross linking of polymer chain due to ion beam irradiation which is also corroborated with XRD analysis. Dependence of dielectric properties on frequency, ions and filler concentration was studied. The results revealed the enhancement in dielectric properties after doping nanoparticles and also upon irradiation. It was observed that the effect of Si-beam is more effectual than the C-beam because of large electronic energy loss of heavy ion.

Studies of tin-transition metal-carbon and tin-cobalt-transition metal-carbon negative electrode materials prepared by mechanical attrition

NASA Astrophysics Data System (ADS)

Ferguson, P. P.; Martine, M. L.; George, A. E.; Dahn, J. R.

Samples of Sn 30TM 30C 40 and of Sn 30Co 15TM 15C 40, with TM = 3d transition metals, were prepared by vertical-axis attritor milling. The structure and performance of these samples were studied by X-ray diffraction (XRD) and by electrochemical testing. The XRD patterns of Sn 30TM 30C 40 show an amorphous-like diffraction pattern only for the sample with TM = Co. The other prepared samples show broadened Bragg peaks of their main starting material, along with an amorphous-like background, even after 32 h of milling. Samples with TM = Co and TM = Ni show stable differential capacity versus potential plots and stable cycling for at least 100 cycles with reversible capacities of 425 and 250 mAh g -1, respectively. All samples prepared with 15 at.% Co show good capacity retention for at least 100 cycles ranging from 270 mAh g -1 for samples with TM = Ni to 500 mAh g -1 for samples with TM = Ti. The differential capacity versus potential plots for all the prepared Sn 30Co 15TM 15C 40 samples show similar structure to that of Sn 30Co 30C 40 except when TM = Cu. This shows the possibility of preparing tin-based negative electrode materials using a combination of cobalt and TM, especially if one looks to reduce the cobalt content.

Supercooled smectic nanoparticles: a potential novel carrier system for poorly water soluble drugs.

PubMed

Kuntsche, J; Westesen, K; Drechsler, M; Koch, M H J; Bunjes, H

2004-10-01

The possibility of preparing nanoparticles in the supercooled thermotropic liquid crystalline state from cholesterol esters with saturated acyl chains as well as the incorporation of model drugs into the dispersions was investigated using cholesteryl myristate (CM) as a model cholesterol ester. Nanoparticles were prepared by high-pressure melt homogenization or solvent evaporation using phospholipids, phospholipid/ bile salt, or polyvinyl alcohol as emulsifiers. The physicochemical state and phase behavior of the particles was characterized by particle size measurements (photon correlation spectroscopy, laser diffraction with polarization intensity differential scattering), differential scanning calorimetry, X-ray diffraction, and electron and polarizing light microscopy. The viscosity of the isotropic and liquid crystalline phases of CM in the bulk was investigated in dependence on temperature and shear rate by rotational viscometry. CM nanoparticies can be obtained in the smectic phase and retained in this state for at least 12 months when stored at 230C in optimized systems. The recrystallization tendency of CM in the dispersions strongly depends on the stabilizer system and the particle size. Stable drug-loaded smectic nanoparticles were obtained after incorporation of 10% (related to CM) ibuprofen, miconazole, etomidate, and 1% progesterone. Due to their liquid crystalline state, colloidal smectic nanoparticles offer interesting possibilities as carrier system for lipophilic drugs. CM nanoparticles are suitable model systems for studying the crystallization behavior and investigating the influence of various parameters for the development of smectic nanoparticles resistant against recrystallization upon storage.

A study of the phase transition behaviour of [(NH4)0.63Li0.37]2TeBr6

NASA Astrophysics Data System (ADS)

Karray, R.; Linda, D.; Van Der Lee, A.; Ben Salah, A.; Kabadou, A.

2012-02-01

The mixed hexabromotellurate [(NH4)0.63Li0.37]2TeBr6, presenting at room temperature a K2PtCl6-type structure with space group Fm bar 3 m, exhibits three anomalies at 195, 395 and 498 K in the differential scanning calorimetry diagram. Different techniques: dielectric investigation, High-temperature X-ray powder diffraction and infrared spectroscopic study, in the range temperature (300-470) K are applied to explore the phase transition around 395 K. Combining XRD, dielectric and differential scanning calorimetry (DSC) results, no phase transition leading to a super-ionic conductivity phase is found. At high temperature, [(NH4)0.63Li0.37]2TeBr6 is characterized by a medium conductivity σ453≈ 10-4 Ω-1m-1.

Characterization of melt-quenched and milled amorphous solids of gatifloxacin.

PubMed

Hattori, Yusuke; Suzuki, Ayumi; Otsuka, Makoto

2016-11-01

The objectives of this study were to characterize and investigate the differences in amorphous states of gatifloxacin. We prepared two types of gatifloxacin amorphous solids coded as M and MQ using milling and melt-quenching methods, respectively. The amorphous solids were characterized via X-ray diffraction (XRD), nonisothermal differential scanning calorimetry (DSC) and time-resolved near-infrared (NIR) spectroscopy. Both the solids displayed halo XRD patterns, the characteristic of amorphous solids; however, in the non-isothermal DSC profiles, these amorphous solids were distinguished by their crystallization and melting temperatures. The Kissinger-Akahira-Sunose plots of non-isothermal crystallization temperatures at various heating rates indicated a lower activation energy of crystallization for the amorphous solid M than that of MQ. These results support the differentiation between two amorphous states with different physical and chemical properties.

Electromagnetic beam diffraction by a finite lamellar structure: an aperiodic coupled-wave method.

PubMed

Guizal, Brahim; Barchiesi, Dominique; Felbacq, Didier

2003-12-01

We have developed a new formulation of the coupled-wave method (CWM) to handle aperiodic lamellar structures, and it will be referred to as the aperiodic coupled-wave method (ACWM). The space is still divided into three regions, but the fields are written by use of their Fourier integrals instead of the Fourier series. In the modulated region the relative permittivity is represented by its Fourier transform, and then a set of integro-differential equations is derived. Discretizing the last system leads to a set of ordinary differential equations that is reduced to an eigenvalue problem, as is usually done in the CWM. To assess the method, we compare our results with three independent formalisms: the Rayleigh perturbation method for small samples, the volume integral method, and the finite-element method.

Thermal behavior of potato starch and water-vaporization behavior of its paste controlled with amino acid and peptide-rich food materials.

PubMed

Sakauchi, Satoshi; Hattori, Makoto; Yoshida, Tadashi; Yagishita, Takahiro; Ito, Koichi; Akemitsu, Shin-Ichi; Takahashi, Koji

2010-03-01

The particular effect of 4 kinds of amino acid and peptide-rich food material (APRM) containing different charged amino acid contents on the gelatinization and retrogradation behavior of potato starch granules and on the water-vaporization behavior was analyzed by differential scanning calorimetry, rapid viscoanalysis, x-ray diffractometry, thermal gravimetry-differential thermal analysis, and pulsed NMR. APRM with a high-charged amino acid content produced unique gelatinization and retrogradation behavior in terms of an elevated gelatinization temperature, reduced viscosity, higher setback, and lower retrograded starch melting enthalpy. The recovered x-ray diffraction intensity decreased with increasing charged amino acid content. APRM with high-charged amino acid content could provide an improved paste having easy vaporization of external water in the swollen starch granules due to the reduced swelling.

Accurate Modeling of X-ray Extinction by Interstellar Grains

NASA Astrophysics Data System (ADS)

Hoffman, John; Draine, B. T.

2016-02-01

Interstellar abundance determinations from fits to X-ray absorption edges often rely on the incorrect assumption that scattering is insignificant and can be ignored. We show instead that scattering contributes significantly to the attenuation of X-rays for realistic dust grain size distributions and substantially modifies the spectrum near absorption edges of elements present in grains. The dust attenuation modules used in major X-ray spectral fitting programs do not take this into account. We show that the consequences of neglecting scattering on the determination of interstellar elemental abundances are modest; however, scattering (along with uncertainties in the grain size distribution) must be taken into account when near-edge extinction fine structure is used to infer dust mineralogy. We advertise the benefits and accuracy of anomalous diffraction theory for both X-ray halo analysis and near edge absorption studies. We present an open source Fortran suite, General Geometry Anomalous Diffraction Theory (GGADT), that calculates X-ray absorption, scattering, and differential scattering cross sections for grains of arbitrary geometry and composition.

Growth and characterization of barium complex of 1,3,5-triazinane-2,4,6-trione in gel: a corrosion inhibiting material

NASA Astrophysics Data System (ADS)

Divya, R.; Nair, Lekshmi P.; Bijini, B. R.; Nair, C. M. K.; Babu, K. Rajendra

2018-05-01

Good quality prismatic crystals of industrially applicable corrosion inhibiting barium complex of 1,3,5-triazinane-2,4,6-trione have been grown by conventional gel method. The crystal structure, packing, and nature of bonds are revealed in the single crystal X-ray diffraction analysis. The crystal has a three-dimensional polymeric structure having a triclinic crystal system with the space group P-1. The powder X-ray diffraction analysis confirms its crystalline nature. The functional groups present in the crystal are identified by Fourier transform infrared spectroscopy. Elemental analysis confirms the stoichiometry of the elements present in the complex. Thermogravimetric analysis and differential thermal analysis reveal its good thermal stability. The optical properties like band gap, refractive index and extinction coefficient are evaluated from the UV-visible spectral analysis. The singular property of the material, corrosion inhibition efficiency achieved by the adsorption of the sample molecules is determined by the weight loss method.

Wavefront-aberration measurement and systematic-error analysis of a high numerical-aperture objective

NASA Astrophysics Data System (ADS)

Liu, Zhixiang; Xing, Tingwen; Jiang, Yadong; Lv, Baobin

2018-02-01

A two-dimensional (2-D) shearing interferometer based on an amplitude chessboard grating was designed to measure the wavefront aberration of a high numerical-aperture (NA) objective. Chessboard gratings offer better diffraction efficiencies and fewer disturbing diffraction orders than traditional cross gratings. The wavefront aberration of the tested objective was retrieved from the shearing interferogram using the Fourier transform and differential Zernike polynomial-fitting methods. Grating manufacturing errors, including the duty-cycle and pattern-deviation errors, were analyzed with the Fourier transform method. Then, according to the relation between the spherical pupil and planar detector coordinates, the influence of the distortion of the pupil coordinates was simulated. Finally, the systematic error attributable to grating alignment errors was deduced through the geometrical ray-tracing method. Experimental results indicate that the measuring repeatability (3σ) of the wavefront aberration of an objective with NA 0.4 was 3.4 mλ. The systematic-error results were consistent with previous analyses. Thus, the correct wavefront aberration can be obtained after calibration.

Diffractive dijet cross sections in photoproduction at HERA

NASA Astrophysics Data System (ADS)

Breitweg, J.; Derrick, M.; Krakauer, D.; Magill, S.; Mikunas, D.; Musgrave, B.; Repond, J.; Stanek, R.; Talaga, R. L.; Yoshida, R.; Zhang, H.; Mattingly, M. C. K.; Anselmo, F.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Romeo, G. Cara; Castellini, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Coppola, N.; Corradi, M.; de Pasquale, S.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Polini, A.; Sartorelli, G.; Garcia, Y. Zamora; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Coböken, K.; Crittenden, J.; Deffner, R.; Eckert, M.; Grothe, M.; Hartmann, H.; Heinloth, K.; Heinz, L.; Hilger, E.; Jakob, H.-P.; Kappes, A.; Katz, U. F.; Kerger, R.; Paul, E.; Pfeiffer, M.; Stamm, J.; Wieber, H.; Bailey, D. S.; Campbell-Robson, S.; Cottingham, W. N.; Foster, B.; Hall-Wilton, R.; Heath, G. P.; Heath, H. F.; McFall, J. D.; Piccioni, D.; Roff, D. G.; Tapper, R. J.; Ayad, R.; Capua, M.; Iannotti, L.; Schioppa, M.; Susinno, G.; Kim, J. Y.; Lee, J. H.; Lim, I. T.; Pac, M. Y.; Caldwell, A.; Cartiglia, N.; Jing, Z.; Liu, W.; Mellado, B.; Parsons, J. A.; Ritz, S.; Sampson, S.; Sciulli, F.; Straub, P. B.; Zhu, Q.; Borzemski, P.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Klimek, K.; Przybycień, M. B.; Zawiejski, L.; Adamczyk, L.; Bednarek, B.; Bukowy, M.; Czermak, A. M.; Jeleń, K.; Kisielewska, D.; Kowalski, T.; Przybycień, M.; Rulikowska-Zarbska, E.; Suszycki, L.; Zajc, J.; Duliński, Z.; Kotański, A.; Abbiendi, G.; Bauerdick, L. A. T.; Behrens, U.; Beier, H.; Bienlein, J. K.; Desler, K.; Drews, G.; Fricke, U.; Gialas, I.; Goebel, F.; Göttlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hasell, D.; Hebbel, K.; Johnson, K. F.; Kasemann, M.; Koch, W.; Kötz, U.; Kowalski, H.; Lindemann, L.; Löhr, B.; Milewski, J.; Milite, M.; Monteiro, T.; Ng, J. S. T.; Notz, D.; Park, I. H.; Pellegrino, A.; Pelucchi, F.; Piotrzkowski, K.; Rohde, M.; Roldán, J.; Ryan, J. J.; Savin, A. A.; Schneekloth, U.; Schwarzer, O.; Selonke, F.; Stonjek, S.; Surrow, B.; Tassi, E.; Westphal, D.; Wolf, G.; Wollmer, U.; Youngman, C.; Zeuner, W.; Burow, B. D.; Coldewey, C.; Grabosch, H. J.; Meyer, A.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P.; Maccarrone, G.; Votano, L.; Bamberger, A.; Eisenhardt, S.; Markun, P.; Raach, H.; Trefzger, T.; Wölfle, S.; Bromley, J. T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; MacDonald, N.; Saxon, D. H.; Sinclair, L. E.; Skillicorn, I. O.; Strickland, E.; Waugh, R.; Bohnet, I.; Gendner, N.; Holm, U.; Meyer-Larsen, A.; Salehi, H.; Wick, K.; Garfagnini, A.; Gladilin, L. K.; Horstmann, D.; Kçira, D.; Klanner, R.; Lohrmann, E.; Poelz, G.; Schott, W.; Zetsche, F.; Bacon, T. C.; Butterworth, I.; Cole, J. E.; Howell, G.; Lamberti, L.; Long, K. R.; Miller, D. B.; Pavel, N.; Prinias, A.; Sedgbeer, J. K.; Sideris, D.; Walker, R.; Mallik, U.; Wang, S. M.; Wu, J. T.; Cloth, P.; Filges, D.; Fleck, J. I.; Ishii, T.; Kuze, M.; Suzuki, I.; Tokushuku, K.; Yamada, S.; Yamauchi, K.; Yamazaki, Y.; Hong, S. J.; Lee, S. B.; Nam, S. W.; Park, S. K.; Barreiro, F.; Fernández, J. P.; García, G.; Glasman, C.; Hernández, J. M.; Hervás, L.; Labarga, L.; Martínez, M.; Peso, J. Del; Puga, J.; Terrón, J.; Trocóniz, J. F. De; Corriveau, F.; Hanna, D. S.; Hartmann, J.; Hung, L. W.; Murray, W. N.; Ochs, A.; Riveline, M.; Stairs, D. G.; St-Laurent, M.; Ullmann, R.; Tsurugai, T.; Bashkirov, V.; Dolgoshein, B. A.; Stifutkin, A.; Bashindzhagyan, G. L.; Ermolov, P. F.; Golubkov, Yu. A.; Khein, L. A.; Korotkova, N. A.; Korzhavina, I. A.; Kuzinin, V. A.; Lukina, O. Yu.; Proskuryakov, A. S.; Shcheglova, L. M.; Solomin, A. N.; Zotkin, S. A.; Bokel, C.; Botje, M.; Brümmer, N.; Engelen, J.; Koffeman, E.; Kooijman, P.; van Sighem, A.; Tiecke, H.; Tuning, N.; Verkerke, W.; Vossebeld, J.; Wiggers, L.; Wolf, E. De; Acosta, D.; Bylsma, B.; Durkin, L. S.; Gilmore, J.; Ginsburg, C. M.; Kim, C. L.; Ling, T. Y.; Nylander, P.; Romanowski, T. A.; Blaikley, H. E.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Edmonds, J. K.; Große-Knetter, J.; Harnew, N.; Nath, C.; Noyes, V. A.; Quadt, A.; Ruske, O.; Tickner, J. R.; Walczak, R.; Waters, D. S.; Bertolin, A.; Brugnera, R.; Carlin, R.; Corso, F. Dal; Dosselli, U.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Bulmahn, J.; Oh, B. Y.; Okrasiński, J. R.; Toothacker, W. S.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Raso, M.; Hart, J. C.; McCubbin, N. A.; Shah, T. P.; Epperson, D.; Heusch, C.; Rahn, J. T.; Sadrozinski, H. F.-W.; Seiden, A.; Wichmann, R.; Williams, D. C.; Abramowicz, H.; Briskin, G.; Dagan, S.; Kananov, S.; Levy, A.; Abe, T.; Fusayasu, T.; Inuzuka, M.; Nagano, K.; Umemori, K.; Yamashita, T.; Hamatsu, R.; Hirose, T.; Homma, K.; Kitamura, S.; Matsushita, T.; Arneodo, M.; Cirio, R.; Costa, M.; Ferrero, M. I.; Maselli, S.; Monaco, V.; Peroni, C.; Petrucci, M. C.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Dardo, M.; Bailey, D. C.; Fagerstroem, C.-P.; Galea, R.; Hartner, G. F.; Joo, K. K.; Levman, G. M.; Martin, J. F.; Orr, R. S.; Polenz, S.; Sabetfakhri, A.; Simmons, D.; Teuscher, R. J.; Butterworth, J. M.; Catterall, C. D.; Hayes, M. E.; Jones, T. W.; Lane, J. B.; Saunders, R. L.; Sutton, M. R.; Wing, M.; Ciborowski, J.; Grzelak, G.; Kasprzak, M.; Nowak, R. J.; Pawlak, J. M.; Pawlak, R.; Tymieniecka, T.; Wróblewski, A. K.; Zakrzewski, J. A.; Zarnecki, A. F.; Adamus, M.; Deppe, O.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Badgett, W. F.; Chapin, D.; Cross, R.; Dasu, S.; Foudas, C.; Loveless, R. J.; Mattingly, S.; Reeder, D. D.; Smith, W. H.; Vaiciulis, A.; Wodarczyk, M.; Deshpande, A.; Dhawan, S.; Hughes, V. W.; Bhadra, S.; Frisken, W. R.; Khakzad, M.; Schmidke, W. B.

1998-08-01

Differential dijet cross sections have been measured with the ZEUS detector for photoproduction events in which the hadronic final state containing the jets is separated with respect to the outgoing proton direction by a large rapidity gap. The cross section has been measured as a function of the fraction of the photon (ϰγ OBS) and pomeron (β OBS) momentum participating in the production of the dijet system. The observed ϰγ OBS dependence shows evidence for the presence of a resolved- as well as a direct-photon component. The measured cross section da/dβ OBS increases as β OBS increases indicating that there is a sizeable contribution to dijet production from those events in which a large fraction of the pomeron momentum participates in the hard scattering. These cross sections and the ZEUS measurements of the diffractive structure function can be described by calculations based on parton densities in the pomeron which evolve according to the QCD evolution equations and include a substantial hard momentum component of gluons in the pomeron.

Neutron diffraction study, magnetic properties and thermal stability of YMn 2D 6 synthesized under high deuterium pressure

NASA Astrophysics Data System (ADS)

Paul-Boncour, V.; Filipek, S. M.; Dorogova, M.; Bourée, F.; André, G.; Marchuk, I.; Percheron-Guégan, A.; Liu, R. S.

2005-01-01

A new phase YMn 2D 6 was synthesized by submitting YMn 2 to 1.7 kbar deuterium pressure at 473 K. According to X-ray and neutron powder diffraction experiments, YMn 2D 6 crystallizes in the Fm3¯m space group with a=6.709(1) Å at 300 K. The Y and half of the Mn atoms occupy statistically the 8 c site whereas the other Mn atoms are located in 4 a site and surrounded by 6 D atoms (24 e). This corresponds to a K 2PtCl 6-type structure with a partially disordered substructure which can be written as [YMn]MnH 6. No ordered magnetic moment is observed in the NPD patterns and the magnetization measurements display a paramagnetic behavior. The study of the thermal stability by Differential Scanning Calorimetry and XRD experiments indicates that this phase decomposes in YD 2 and Mn at 625 K, and is more stable than YMn 2H 4.5.

In Situ XRD Studies of the Process Dynamics During Annealing in Cold-Rolled Copper

NASA Astrophysics Data System (ADS)

Dey, Santu; Gayathri, N.; Bhattacharya, M.; Mukherjee, P.

2016-12-01

The dynamics of the release of stored energy during annealing along two different crystallographic planes, i.e., {111} and {220}, in deformed copper have been investigated using in situ X-ray diffraction measurements at 458 K and 473 K (185 °C and 200 °C). The study has been carried out on 50 and 80 pct cold-rolled Cu sheets. The microstructures of the rolled samples have been characterized using optical microscopy and electron backscattered diffraction measurements. The microstructural parameters were evaluated from the X-ray diffractogram using the Scherrer equation and the modified Rietveld method. The stored energy along different planes was determined using the modified Stibitz formula from the X-ray peak broadening, and the bulk stored energy was evaluated using differential scanning calorimetry. The process dynamics of recovery and recrystallization as observed through the release of stored energy have been modeled as the second-order and first-order processes, respectively.

Illite polytype quantification using Wildfire© calculated x-ray diffraction patterns

USGS Publications Warehouse

Grathoff, Georg H.; Moore, D.M.

1996-01-01

Illite polytype quantification allows the differentiation of diagenetic and detrital illite components. In Paleozoic shales from the Illinois Basin, we observe 3 polytypes: 1Md, 1M and 2M1. 1Md and 1M are of diagenetic origin and 2M1 is of detrital origin. In this paper, we compare experimental X-ray diffraction (XRD) traces with traces calculated using WILDFIRE© and quantify mixtures of all 3 polytypes, adjusting the effects of preferred orientation and overlapping peaks. The broad intensity (“illite hump”) around the illite 003, which is very common in illite from shales, is caused by the presence of 1Md illite and mixing of illite polytypes and is not an artifact of sample preparation or other impurities in the sample. Illite polytype quantification provides a tool to extrapolate the K/Ar age and chemistry of the detrital and diagenetic end-members by analysis of different size fractions containing different proportions of diagenetic and detrital illite polytypes.

Investigation of phase evolution of CaCu3Ti4O12 (CCTO) by in situ synchrotron high-temperature powder diffraction

NASA Astrophysics Data System (ADS)

Ouyang, Xin; Huang, Saifang; Zhang, Weijun; Cao, Peng; Huang, Zhaohui; Gao, Wei

2014-03-01

In situ synchrotron X-ray powder diffraction was used to study the high-temperature phase evolution of CaCu3Ti4O12 (CCTO) precursors prepared via solid-state and sol-gel methods. After the precursors are heated to 1225 °C, the CCTO phase is the main phase observed in the calcined powder, with the presence of some minor impurities. Comparing the two precursors, we found that the onset temperature for the CCTO phase formation is 800 °C in the sol-gel precursor, lower than that in the solid-state precursor (875 °C). Intermediate phases were only observed in the sol-gel precursor. Both precursors are able to be calcined to sub-micrometric sized powders. Based on the synchrotron data along with differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the phase formation sequence and mechanism during calcination are proposed in this study.

Crystallization and preliminary X-ray diffraction analysis of ScrY, a specific bacterial outer membrane porin.

PubMed

Forst, D; Schülein, K; Wacker, T; Diederichs, K; Kreutz, W; Benz, R; Welte, W

1993-01-05

The sucrose-specific outer membrane porin ScrY of Salmonella typhimurium was isolated from Escherichia coli K-12 strain KS 26 containing the plasmid pPSO112. The protein was purified to homogeneity by differential extraction of the cell envelope in the presence of the detergents sodium dodecyl sulfate and lauryl (dimethyl)-amine oxide (LDAO). The porin had apparent molecular weights of 58 kDa and 120 kDa for the monomer and for the trimer, respectively, on SDS/PAGE. The purified trimers were crystallized using poly(ethylene glycol) 2000 and the detergents octylglucoside (OG) and hexyl-(dimethyl)-amine oxide (C6DAO). X-ray diffraction of the crystals showed reflections to 2.3 A. The space group of the crystals was R3 and the lattice constants of the hexagonal axes were a = b = 112.85 A and c = 149.9 A. The crystal volume per unit of protein molecular weight was 3.47 A3/Da.

Driving forces of redistribution of elements during quasicrystalline phase formation under heating of mechanically alloyed Al65Cu23Fe12 powder

NASA Astrophysics Data System (ADS)

Tcherdyntsev, V. V.; Kaloshkin, S. D.; Shelekhov, E. V.; Principi, G.; Rodin, A. O.

2008-02-01

Al65Cu23Fe12 alloys were prepared by ball milling of the elemental powders mixture. Phase and structural transformations at heating of as-milled powders were investigated by X-ray diffraction analysis. Precision analysis of Mössbauer spectra was performed to check the adequacy of the fitting of X-ray diffraction patterns. The results were compared with the data of differential scanning and solution calorimetry, as well as with the thermodynamic literature data, in order to estimate the driving forces of redistribution of elements that preceded the formation of single-phase quasicrystalline structure. The heat of elements mixing, which is positive for Cu-Fe system and negative for Al-Fe and Al-Cu systems, was supposed to be a decisive factor for phase transformations during heating of the alloy. The correlation between sequence of phase transformations during heating and the thermodynamic data was discussed and the scheme describing phase transformations observed was proposed.

Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction.

PubMed

Müller, Knut; Krause, Florian F; Béché, Armand; Schowalter, Marco; Galioit, Vincent; Löffler, Stefan; Verbeeck, Johan; Zweck, Josef; Schattschneider, Peter; Rosenauer, Andreas

2014-12-15

By focusing electrons on probes with a diameter of 50 pm, aberration-corrected scanning transmission electron microscopy (STEM) is currently crossing the border to probing subatomic details. A major challenge is the measurement of atomic electric fields using differential phase contrast (DPC) microscopy, traditionally exploiting the concept of a field-induced shift of diffraction patterns. Here we present a simplified quantum theoretical interpretation of DPC. This enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright-field detectors. The methodical development yielding atomic electric field, charge and electron density is performed using simulations for binary GaN as an ideal model system. We then present a detailed experimental study of SrTiO3 yielding atomic electric fields, validated by comprehensive simulations. With this interpretation and upgraded instrumentation, STEM is capable of quantifying atomic electric fields and high-contrast imaging of light atoms.

Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction

NASA Astrophysics Data System (ADS)

Müller, Knut; Krause, Florian F.; Béché, Armand; Schowalter, Marco; Galioit, Vincent; Löffler, Stefan; Verbeeck, Johan; Zweck, Josef; Schattschneider, Peter; Rosenauer, Andreas

2014-12-01

By focusing electrons on probes with a diameter of 50 pm, aberration-corrected scanning transmission electron microscopy (STEM) is currently crossing the border to probing subatomic details. A major challenge is the measurement of atomic electric fields using differential phase contrast (DPC) microscopy, traditionally exploiting the concept of a field-induced shift of diffraction patterns. Here we present a simplified quantum theoretical interpretation of DPC. This enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright-field detectors. The methodical development yielding atomic electric field, charge and electron density is performed using simulations for binary GaN as an ideal model system. We then present a detailed experimental study of SrTiO3 yielding atomic electric fields, validated by comprehensive simulations. With this interpretation and upgraded instrumentation, STEM is capable of quantifying atomic electric fields and high-contrast imaging of light atoms.

Fixed target matrix for femtosecond time-resolved and in situ serial micro-crystallography

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

Mueller, C.; Marx, A.; Epp, S. W.

We present a crystallography chip enabling in situ room temperature crystallography at microfocus synchrotron beamlines and X-ray free-electron laser (X-FEL) sources. Compared to other in situ approaches, we observe extremely low background and high diffraction data quality. The chip design is robust and allows fast and efficient loading of thousands of small crystals. The ability to load a large number of protein crystals, at room temperature and with high efficiency, into prescribed positions enables high throughput automated serial crystallography with microfocus synchrotron beamlines. In addition, we demonstrate the application of this chip for femtosecond time-resolved serial crystallography at the Linacmore » Coherent Light Source (LCLS, Menlo Park, California, USA). As a result, the chip concept enables multiple images to be acquired from each crystal, allowing differential detection of changes in diffraction intensities in order to obtain high signal-to-noise and fully exploit the time resolution capabilities of XFELs.« less

Fixed target matrix for femtosecond time-resolved and in situ serial micro-crystallography

DOE PAGES

Mueller, C.; Marx, A.; Epp, S. W.; ...

2015-08-18

We present a crystallography chip enabling in situ room temperature crystallography at microfocus synchrotron beamlines and X-ray free-electron laser (X-FEL) sources. Compared to other in situ approaches, we observe extremely low background and high diffraction data quality. The chip design is robust and allows fast and efficient loading of thousands of small crystals. The ability to load a large number of protein crystals, at room temperature and with high efficiency, into prescribed positions enables high throughput automated serial crystallography with microfocus synchrotron beamlines. In addition, we demonstrate the application of this chip for femtosecond time-resolved serial crystallography at the Linacmore » Coherent Light Source (LCLS, Menlo Park, California, USA). As a result, the chip concept enables multiple images to be acquired from each crystal, allowing differential detection of changes in diffraction intensities in order to obtain high signal-to-noise and fully exploit the time resolution capabilities of XFELs.« less

Optical, electrochemical and thermal properties of Mn2+ doped CdS nanoparticles

NASA Astrophysics Data System (ADS)

Muruganandam, S.; Anbalagan, G.; Murugadoss, G.

2015-08-01

Mn2+ doped (1-5 and 10 %) CdS nanoparticles have been synthesized by the chemical precipitation method using polyvinylpyrrolidone as a capping agent. The particle size, morphology and optical properties have been studied by X-ray powder diffraction, transmission electron microscopy, UV-Visible and photoluminescence spectroscopy. Powder diffraction data have confirmed that the crystallite size is around 2-5 nm. The band gap of the nanoparticles has been calculated using UV-Visible absorption spectra. An optimum concentration, Mn2+ (3 %) has been selected by optical study. The functional groups of the capping agent have been identified by fourier transform infrared spectroscopy study. The presence of dopant (Mn2+) has been confirmed by electron paramagnetic resonance spectroscopy. Thermal properties of CdS:Mn2+ have been analyzed using thermogravimetric-differential thermal analyser. The electrochemical properties of the undoped and doped samples have been studied by cyclic voltammetry for electrode applications. In addition, magnetic properties of Mn2+ doped CdS have been studied using a vibrating sample magnetometer.

Analysis of submicron-sized niflumic acid crystals prepared by electrospray crystallization.

PubMed

Ambrus, Rita; Radacsi, Norbert; Szunyogh, Tímea; van der Heijden, Antoine E D M; Ter Horst, Joop H; Szabó-Révész, Piroska

2013-03-25

Interest in submicron-sized drug particles has emerged from both laboratory and industrial perspectives in the last decade. Production of crystals in the nano size scale offers a novel way to particles for drug formulation solving formulation problems of drugs with low solubility in class II of the Biopharmaceutical Classification System. In this work niflumic acid nanoparticles with a size range of 200-800nm were produced by the novel crystallization method, electrospray crystallization. Their properties were compared to those from evaporative and anti-solvent crystallizations, using the same organic solvent, acetone. There is a remarkable difference in the product crystal size depending on the applied methods. The size and morphology were analyzed by scanning electron microscopy and laser diffraction. The structure of the samples was investigated using differential scanning calorimetry, Fourier-transformed infrared spectroscopy and X-ray powder diffraction. The particles produced using electrospray crystallization process were probably changing from amorphous to crystalline state after the procedure. Copyright © 2012 Elsevier B.V. All rights reserved.

Search for dilute excited states in 16O

NASA Astrophysics Data System (ADS)

Ogloblin, A. A.; Danilov, A. N.; Demyanova, A. S.; Goncharov, S. A.; Belyaeva, T. L.

2016-11-01

The root mean square radii of 16O in the short-lived 0+ excited states were experimentally deduced for the first time from the analyses of α +16O diffraction scattering. Differential cross sections of the elastic and inelastic α +16O and 16O+16O scattering in the incident energy range from a few MeV/nucleon up to 100 MeV/nucleon were analyzed by the modified diffraction model. No significant radius enhancement in any state in comparison with the ground state was observed. This concerns, in particular, the 15.1-MeV 06+ state of 16O, located in the vicinity of the four-α -particle complete dissociation threshold, for which we did not confirm the "gigantic" size predicted by the α -particle condensation model. This result does not support the idea that 16O in the 06+ state has a dilute structure and can be considered as an analog of the famous 7.65-MeV 02+ Hoyle state of 12C.

Occurrence of amylose-lipid complexes in teff and maize starch biphasic pastes.

PubMed

Wokadala, Obiro Cuthbert; Ray, Suprakas Sinha; Emmambux, Mohammad Naushad

2012-09-01

The occurrence of amylose-lipid complexes was determined in maize and teff starch biphasic pastes i.e. peak viscosity pastes at short and prolonged pasting times. Maize and teff starches were pasted for 11.5 and 130 min with or without added stearic acid followed by thermo-stable alpha-amylase hydrolysis in a rapid visco-analyzer. X-ray diffraction analysis of pastes before and residues after hydrolysis showed crystalline V-amylose diffraction patterns for the starches pasted for a prolonged time with added stearic acid while less distinct V-amylose patterns with non-complexed stearic acid peaks were observed with a short pasting time. Differential scanning calorimetry of pastes before and residues after paste hydrolysis showed that Type I amylose-lipid complexes were formed after pasting for the short duration with added stearic acid, while Type II complexes are formed after pasting for the prolonged time. The present research provides evidence that amylose-lipid complexes play an important role in starch biphasic pasting. Copyright © 2012 Elsevier Ltd. All rights reserved.

Monitoring of CoS 2 reactions using high-temperature XRD coupled with gas chromatography (GC)

DOE PAGES

Rodriguez, Mark A.; Coker, Eric Nicholas; Griego, James J. M.; ...

2016-04-18

High-temperature X-ray diffraction with concurrent gas chromatography (GC) was used to study cobalt disulfide cathode pellets disassembled from thermal batteries. When CoS 2 cathode materials were analyzed in an air environment, oxidation of the K(Br, Cl) salt phase in the cathode led to the formation of K 2SO 4 that subsequently reacted with the pyrite-type CoS 2 phase leading to cathode decomposition between ~260 and 450 °C. Here, independent thermal analysis experiments, i.e. simultaneous thermogravimetric analysis/differential scanning calorimetry/mass spectrometry (MS), augmented the diffraction results and support the overall picture of CoS 2 decomposition. Both gas analysis measurements (i.e. GC andmore » MS) from the independent experiments confirmed the formation of SO 2 off-gas species during breakdown of the CoS 2. In contrast, characterization of the same cathode material under inert conditions showed the presence of CoS 2 throughout the entire temperature range of analysis.« less

Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction

PubMed Central

Müller, Knut; Krause, Florian F.; Béché, Armand; Schowalter, Marco; Galioit, Vincent; Löffler, Stefan; Verbeeck, Johan; Zweck, Josef; Schattschneider, Peter; Rosenauer, Andreas

2014-01-01

By focusing electrons on probes with a diameter of 50 pm, aberration-corrected scanning transmission electron microscopy (STEM) is currently crossing the border to probing subatomic details. A major challenge is the measurement of atomic electric fields using differential phase contrast (DPC) microscopy, traditionally exploiting the concept of a field-induced shift of diffraction patterns. Here we present a simplified quantum theoretical interpretation of DPC. This enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright-field detectors. The methodical development yielding atomic electric field, charge and electron density is performed using simulations for binary GaN as an ideal model system. We then present a detailed experimental study of SrTiO3 yielding atomic electric fields, validated by comprehensive simulations. With this interpretation and upgraded instrumentation, STEM is capable of quantifying atomic electric fields and high-contrast imaging of light atoms. PMID:25501385

Sulfaguanidine cocrystals: Synthesis, structural characterization and their antibacterial and hemolytic analysis.

PubMed

Abidi, Syed Sibte Asghar; Azim, Yasser; Khan, Shahper Nazeer; Khan, Asad U

2018-02-05

Sulfaguanidine (SG), belongs to the class of sulfonamide drug used as an effective antibiotic. In the present work, using crystal engineering approach two novel cocrystals of SG were synthesized (SG-TBA and SG-PT) with thiobarbutaric acid (TBA) and 1,10-phenanthroline (PT), characterized by solid state techniques viz., powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and the crystal structures were determined by single crystal X-ray diffraction studies. A comparative antibacterial activity and hemolytic potential was done on SG drug, coformers and their cocrystals. The tested cocrystals formulations showed almost two fold higher antibacterial activity against the tested strains of bacteria Gram-positive bacteria (S. mutans and E. faecalis) and Gram-negative bacteria (E. coli, K. pneumonia and E. clocae) over SG alone and their coformers. Cocrystal SG-TBA showed better antibacterial activity and reduced hemolysis, thereby, reduced cytotoxicity than SG-PT. Copyright © 2017 Elsevier B.V. All rights reserved.

Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis

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

Liu Q.; Hendrickson, W.

2017-01-01

The normal elastic X-ray scattering that depends only on electron density can be modulated by an ?anomalous? component due to resonance between X-rays and electronic orbitals. Anomalous scattering thereby precisely identifies atomic species, since orbitals distinguish atomic elements, which enables the multi- and single-wavelength anomalous diffraction (MAD and SAD) methods. SAD now predominates in de novo structure determination of biological macromolecules, and we focus here on the prevailing SAD method. We describe the anomalous phasing theory and the periodic table of phasing elements that are available for SAD experiments, differentiating between those readily accessible for at-resonance experiments and those thatmore » can be effective away from an edge. We describe procedures for present-day SAD phasing experiments and we discuss optimization of anomalous signals for challenging applications. We also describe methods for using anomalous signals as molecular markers for tracing and element identification. Emerging developments and perspectives are discussed in brief.« less

Optical determination of crystal phase in semiconductor nanocrystals

PubMed Central

Lim, Sung Jun; Schleife, André; Smith, Andrew M.

2017-01-01

Optical, electronic and structural properties of nanocrystals fundamentally derive from crystal phase. This is especially important for polymorphic II–VI, III–V and I-III-VI2 semiconductor materials such as cadmium selenide, which exist as two stable phases, cubic and hexagonal, each with distinct properties. However, standard crystallographic characterization through diffraction yields ambiguous phase signatures when nanocrystals are small or polytypic. Moreover, diffraction methods are low-throughput, incompatible with solution samples and require large sample quantities. Here we report the identification of unambiguous optical signatures of cubic and hexagonal phases in II–VI nanocrystals using absorption spectroscopy and first-principles electronic-structure theory. High-energy spectral features allow rapid identification of phase, even in small nanocrystals (∼2 nm), and may help predict polytypic nanocrystals from differential phase contributions. These theoretical and experimental insights provide simple and accurate optical crystallographic analysis for liquid-dispersed nanomaterials, to improve the precision of nanocrystal engineering and improve our understanding of nanocrystal reactions. PMID:28513577

Crystal Structure Variations of Sn Nanoparticles upon Heating

NASA Astrophysics Data System (ADS)

Mittal, Jagjiwan; Lin, Kwang-Lung

2018-04-01

Structural changes in Sn nanoparticles during heating below the melting point have been investigated using differential scanning calorimetry (DSC), x-ray diffraction (XRD) analysis, electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). DSC revealed that the heat required to melt the nanoparticles (28.43 J/g) was about half compared with Sn metal (52.80 J/g), which was attributed to the large surface energy contribution for the nanoparticles. ED and XRD analyses of the Sn nanoparticles revealed increased intensity for crystal planes having large interplaner distances compared with regular crystal planes with increasing heat treatment temperature (HTT). HRTEM revealed an increase in interlayer spacing at the surface and near joints between nanoparticles with the HTT, leading to an amorphous structure of nanoparticles at the surface at 220°C. These results highlight the changes that occur in the morphology and crystal structure of Sn nanoparticles at the surface and in the interior with increase of the heat treatment temperature.

Coplanar three-beam interference and phase edge dislocations

NASA Astrophysics Data System (ADS)

Patorski, Krzysztof; SłuŻewski, Łukasz; Trusiak, Maciej; Pokorski, Krzysztof

2016-12-01

We present a comprehensive analysis of grating three-beam interference to discover a broad range of the ratio of amplitudes A of +/-1 diffraction orders and the zero order amplitude C providing phase edge dislocations. We derive a condition A/C > 0.5 for the occurrence of phase edge dislocations in three-beam interference self-image planes. In the boundary case A/C = 0.5 singularity conditions are met in those planes (once per interference field period), but the zero amplitude condition is not accompanied by an abrupt phase change. For A/C > 0.5 two adjacent singularities in a single field period show opposite sign topological charges. The occurrence of edge dislocations for selected values of A/C was verified by processing fork fringes obtained by introducing the fourth beam in the plane perpendicular to the one containing three coplanar diffraction orders. Two fork pattern processing methods are described, 2D CWT (two-dimensional continuous wavelet transform) and 2D spatial differentiation.

First compositional evidences on the local production of Dressel 2-4 amphorae in Calabria (Southern Italy): characterization and mixing simulations

NASA Astrophysics Data System (ADS)

Miriello, D.; Bloise, A.; De Luca, R.; Apollaro, C.; Crisci, G. M.; Medaglia, S.; Taliano Grasso, A.

2015-06-01

Dressel 2-4 amphorae are a type of pottery, which was used to transport wine and produced in the Mediterranean area between the first century BC and the second century AD. This study shows, for the first time, that their production also occurred in Ionian Calabria. These results were achieved by studying 11 samples of archaeological pottery (five samples of Dressel 2-4 and six samples of other ceramic types) taken from Cariati (Calabria—Southern Italy). The composition of the pottery was compared with that of the local raw materials (clays and sands) potentially usable for their production. Samples were studied by polarized optical microscopy and analysed by XRF, XRPD and Raman spectroscopy. An innovative approach, based on Microsoft Excel optimizer "Solver" add-in on geochemical data, was used to define the provenance of archaeological pottery and to calculate the mixtures of local clay and sand needed for the production of the pottery itself.

Differential polarization nonlinear optical microscopy with adaptive optics controlled multiplexed beams.

PubMed

Samim, Masood; Sandkuijl, Daaf; Tretyakov, Ian; Cisek, Richard; Barzda, Virginijus

2013-09-09

Differential polarization nonlinear optical microscopy has the potential to become an indispensable tool for structural investigations of ordered biological assemblies and microcrystalline aggregates. Their microscopic organization can be probed through fast and sensitive measurements of nonlinear optical signal anisotropy, which can be achieved with microscopic spatial resolution by using time-multiplexed pulsed laser beams with perpendicular polarization orientations and photon-counting detection electronics for signal demultiplexing. In addition, deformable membrane mirrors can be used to correct for optical aberrations in the microscope and simultaneously optimize beam overlap using a genetic algorithm. The beam overlap can be achieved with better accuracy than diffraction limited point-spread function, which allows to perform polarization-resolved measurements on the pixel-by-pixel basis. We describe a newly developed differential polarization microscope and present applications of the differential microscopy technique for structural studies of collagen and cellulose. Both, second harmonic generation, and fluorescence-detected nonlinear absorption anisotropy are used in these investigations. It is shown that the orientation and structural properties of the fibers in biological tissue can be deduced and that the orientation of fluorescent molecules (Congo Red), which label the fibers, can be determined. Differential polarization microscopy sidesteps common issues such as photobleaching and sample movement. Due to tens of megahertz alternating polarization of excitation pulses fast data acquisition can be conveniently applied to measure changes in the nonlinear signal anisotropy in dynamically changing in vivo structures.

Crystal growth, differential gas adsorption, high thermal stability, and reversible coordination of two new barium-organic frameworks, Ba(SBA)(DMF){sub 4} and Ba{sub 2}(BTEC)(H{sub 2}O)

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

Halake, Shobha; Ok, Kang Min, E-mail: kmok@cau.ac.kr

2015-11-15

Single crystals of two barium-organic framework materials, Ba(SBA)(DMF){sub 4} (CAUMOF-15) and Ba{sub 2}(BTEC)(H{sub 2}O) (CAUMOF-16), have been grown through solvothermal reactions (H{sub 2}SBA=4,4′-sulfonyldibenzoic acid and H{sub 4}BTEC=1,2,4,5-benzenetetracarboxylic acid). The crystal structures of the reported frameworks have been determined by single-crystal X-ray diffraction. The materials have been fully characterized by powder X-ray diffraction (PXRD), elemental analyses, Infrared (IR) spectroscopy, and thermogravimetric analyses (TGA). CAUMOF-15 reveals a three-dimensional open-framework that comprises of an inorganic motif with one-dimensional chains and the SBA linkers. CAUMOF-16 shows another three-dimensional backbone consisting of layers of edge-shared BaO{sub 9} and BaO{sub 10} polyhedra, and BTEC pillars. Bothmore » of the 3D frameworks exhibit relatively high thermal stabilities. The PXRD and IR spectral data confirm that CAUMOF-15 and CAUMOF-16 reveal reversible coordinations of the respective solvent molecules, DMF and H{sub 2}O. Gas adsorption properties towards nitrogen, hydrogen, and carbon dioxide have been also investigated. - Graphical abstract: Crystals of two new barium-organic frameworks, Ba(SBA)(DMF){sub 4} and Ba{sub 2}(BTEC)(H{sub 2}O), exhibiting a differential gas adsorption, a high thermal stability, and a reversible coordination of solvent molecules have been grown. - Highlights: • Crystals of two new 3D Ba-MOFs are grown. • The two Ba-MOFs reveal very high thermal stabilities up to ca. 400 °C. • Ba(SBA)(DMF){sub 4} exhibits differential gas adsorption properties. • The two Ba-MOFs show reversible coordination of the solvent molecules.« less

Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

NASA Astrophysics Data System (ADS)

Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

2018-05-01

In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

Structural, thermal, optical, and photoacoustic study of nanocrystalline Bi{sub 2}Te{sub 3} produced by mechanical alloying

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

Souza, S. M.; Triches, D. M.; Poffo, C. M.

2011-01-01

Nanocrystalline Bi{sub 2}Te{sub 3} was produced by mechanical alloying and its properties were investigated by differential scanning calorimetry (DSC) x-ray diffraction (XRD), Raman spectroscopy (RS), and photoacoustic spectroscopy (PAS). Combining the XRD and RS results, the volume fraction of the interfacial component in as-milled and annealed samples was estimated. The PAS results suggest that the contribution of the interfacial component to the thermal diffusivity of nanostructured Bi{sub 2}Te{sub 3} is very significant.

Effect of Thermocycling on the Structure of Martensite and Kinetics of Martensitic Transformation in Alloy Fe - 30% Ni - 3% Pd

NASA Astrophysics Data System (ADS)

Yildiz, Yasin Gokturk; Yildiz, Gokcen Dikici

2017-11-01

The methods of scanning electron microscopy, differential scanning calorimetry and x-ray diffraction are used to study the morphological and thermal characteristics of cooling-induced martensite in alloy Fe - 30% Ni - 3% Pd. It is shown that the kinetics of the martensitic transformation is athermal and the morphology is lamellar. The mean values of the parameters of the austenite and martensite lattices are 0.35704 and 0.28614 nm respectively. The thermocycling leaves the points A s and A f invariable.

Characterization of the adsorption of water vapor and chlorine on microcrystalline silica

NASA Technical Reports Server (NTRS)

Skiles, J. A.; Wightman, J. P.

1979-01-01

The characterization of water adsorption on silica is necessary to an understanding of how hydrogen chloride interacts with silica. The adsorption as a function of outgas temperatures of silica and as a function of the isotherm temperature was studied. Characterization of the silica structure by infrared analysis, X-ray diffraction and differential scanning calorimetry, surface area determinations, characterization of the sample surface by electron spectroscopy for chemical analysis (ESCA), and determinations of the heat of immersion in water of silica were investigated. The silica with a scanning electron microscope was examined.

Studies on the structure of the plant wax nonacosan-10-ol, the main component of epicuticular wax conifers.

PubMed

Matas, Antonio J; Sanz, María José; Heredia, Antonio

2003-11-01

The main component presents in the epicuticular waxes of needles of Pinus halepensis and the most of conifers, the secondary alcohol nonacosan-10-ol, has been investigated by X-ray diffraction and differential scanning calorimetry. The results obtained from these physical techniques permitted to establish a definitive structural model of the molecular arrangement of this wax, basically in good agreement with the model formulated by other authors from theoretical formulations. Biological implications of the proposed structure have been also formulated.

A comparison of choline:urea and choline:oxalic acid deep eutectic solvents at 338 K

NASA Astrophysics Data System (ADS)

Gilmore, Mark; Moura, Leila M.; Turner, Adam H.; Swadźba-Kwaśny, Małgorzata; Callear, Samantha K.; McCune, Jade A.; Scherman, Oren A.; Holbrey, John D.

2018-05-01

1:2 choline chloride:urea and 1:1 choline chloride:oxalic acid deep eutectic solvents are compared at 338 K using liquid-phase neutron diffraction with H/D isotopic substitution to obtain differential neutron scattering cross sections and fitting of models to the experimental data using Empirical Potential Structure Refinement. In comparison to the previously reported study of choline chloride:urea at 303 K, we observed significant weakening and lengthening of choline-OH⋯Cl- and choline-OH⋯hydrogen-bond acceptor correlations.

Vector optical activity in the Weyl semimetal TaAs

DOE PAGES

Norman, M. R.

2015-12-15

Here, it is shown that the Weyl semimetal TaAs can have a significant polar vector contribution to its optical activity. This is quantified by ab initio calculations of the resonant x-ray diffraction at the Ta L1 edge. For the Bragg vector (400), this polar vector contribution to the circular intensity differential between left and right polarized x-rays is predicted to be comparable to that arising from linear dichroism. Implications this result has in regards to optical effects predicted for topological Weyl semimetals are discussed.

Tailoring oxidation of aluminum nanoparticles reinforced with carbon nanotubes

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

Sharma, Manjula; Sharma, Vimal, E-mail: manjula.physics@gmail.com

2016-05-23

In this report, the oxidation temperature and reaction enthalpy of Aluminum (Al) nanoparticles has been controlled by reinforcing with carbon nanotubes. The physical mixing method with ultrasonication was employed to synthesize CNT/Al nanocomposite powders. The micro-morphology of nanoconmposite powders has been analysed by scanning electron microscopy, energy dispersive spectroscopy, Raman spectroscopy and X-ray diffraction techniques. The oxidation behavior of nanocomposite powders analyzed by thermogravimetry/differential scanning calorimertry showed improvement in the exothermic enthalpy. Largest exothermic enthalpy of-1251J/g was observed for CNT (4 wt%)/Al nanocomposite.

Synthesis of Amorphous Powders of Ni-Si and Co-Si Alloys by Mechanical Alloying

NASA Astrophysics Data System (ADS)

Omuro, Keisuke; Miura, Harumatsu

1991-05-01

Amorphous powders of the Ni-Si and Co-Si alloys are synthesized by mechanical alloying (MA) from crystalline elemental powders using a high energy ball mill. The alloying and amorphization process is examined by X-ray diffraction, differential scanning calorimetry (DSC), and scanning electron microscopy. For the Ni-Si alloy, it is confirmed that the crystallization temperature of the MA powder, measured by DSC, is in good agreement with that of the powder sample prepared by mechanical grinding from the cast alloy ingot products of the same composition.

Transition operators in electromagnetic-wave diffraction theory - General theory

NASA Technical Reports Server (NTRS)

Hahne, G. E.

1992-01-01

A formal theory is developed for the scattering of time-harmonic electromagnetic waves from impenetrable immobile obstacles with given linear, homogeneous, and generally nonlocal boundary conditions of Leontovich (impedance) type for the wave of the obstacle's surface. The theory is modeled on the complete Green's function and the transition (T) operator in time-independent formal scattering theory of nonrelativistic quantum mechanics. An expression for the differential scattering cross section for plane electromagnetic waves is derived in terms of certain matrix elements of the T operator for the obstacle.

Structural and thermal properties of γ - irradiated Bombyx mori silk fibroin films

NASA Astrophysics Data System (ADS)

Madhukumar, R.; Asha, S.; Sarojini, B. K.; Somashekar, R.; Rao, B. Lakshmeesha; Shivananda, C. S.; Harish, K. V.; Sangappa

2015-06-01

The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

Coherent diffractive photoproduction of ρ 0 mesons on gold nuclei at 200 GeV/nucleon-pair at the Relativistic Heavy Ion Collider

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

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.

The STAR Collaboration reports on the photoproduction of π + π - pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly real photon emitted by one ion scatters from the other ion. In this work, we fit the π + π - invariant-mass spectrum with a combination of ρ 0 and ω resonances and a direct π + π - continuum. This is the first observation of the ω in ultraperipheral collisions, and the first measurement of ρ - ω interference at energies where photoproduction is dominated by Pomeron exchange.more » The ω amplitude is consistent with the measured γp → ωp cross section, a classical Glauber calculation, and the ω → π + π - branching ratio. The ω phase angle is similar to that observed at much lower energies, showing that the ρ - ω phase difference does not depend significantly on photon energy. The ρ 0 differential cross section dσ/dt exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with two minima visible. In conclusion, the positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.« less

Beam-smiling in bent-Laue monochromators

NASA Astrophysics Data System (ADS)

Ren, B.; Dilmanian, F. A.; Chapman, L. D.; Wu, X. Y.; Zhong, Z.; Ivanov, I.; Thomlinson, W. C.; Huang, X.

1997-07-01

When a wide fan-shaped x-ray beam is diffracted by a bent crystal in the Laue geometry, the profile of the diffracted beam generally does not appear as a straight line, but as a line with its ends curved up or curved down. This effect, referred to as "beam-smiling", has been a major obstacle in developing bent-Laue crystal monochromators for medical applications of synchrotron x-ray. We modeled a cylindrically bent crystal using the Finite Element Analysis (FEA) method, and we carried out experiments at the National Synchrotron Light Source and Cornell High Energy Synchrotron Source. Our studies show that, while beam-smiling exists in most of the crystal's area because of anticlastic bending effects, there is a region parallel to the bending axis of the crystal where the diffracted beam is "smile-free". By applying asymmetrical bending, this smile-free region can be shifted vertically away from the geometric center of the crystal, as desired. This leads to a novel method of compensating for beam-smiling. We will discuss the method of "differential bending" for smile removal, beam-smiling in the Cauchios and the polychromatic geometry, and the implications of the method on developing single- and double-bent Laue monochromators. The experimental results will be discussed, concentrating on specific beam-smiling observation and removal as applied to the new monochromator of the Multiple Energy Computed Tomography [MECT] project of the Medical Department, Brookhaven National Laboratory.

Wave front engineering by means of diffractive optical elements for applications in microscopy

NASA Astrophysics Data System (ADS)

Cojoc, Dan; Ferrari, Enrico; Garbin, Valeria; Cabrini, Stefano; Carpentiero, Alessandro; Prasciolu, Mauro; Businaro, Luca; Kaulich, Burchard; Di Fabrizio, Enzo

2006-05-01

We present a unified view regarding the use of diffractive optical elements (DOEs) for microscopy applications a wide range of electromagnetic spectrum. The unified treatment is realized through the design and fabrication of DOE through which wave front beam shaping is obtained. In particular we show applications ranging from micromanipulation using optical tweezers to X-ray differential interference contrast (DIC) microscopy. We report some details on the design and physical implementation of diffractive elements that beside focusing perform also other optical functions: beam splitting, beam intensity and phase redistribution or mode conversion. Laser beam splitting is used for multiple trapping and independent manipulation of spherical micro beads and for direct trapping and manipulation of biological cells with non-spherical shapes. Another application is the Gauss to Laguerre-Gaussian mode conversion, which allows to trap and transfer orbital angular momentum of light to micro particles with high refractive index and to trap and manipulate low index particles. These experiments are performed in an inverted optical microscope coupled with an infrared laser beam and a spatial light modulator for DOEs implementation. High resolution optics, fabricated by means of e-beam lithography, are demonstrated to control the intensity and the phase of the sheared beams in X-ray DIC microscopy. DIC experiments with phase objects reveal a dramatic increase in image contrast compared to bright-field X-ray microscopy.

Coherent diffractive photoproduction of ρ 0 mesons on gold nuclei at 200 GeV/nucleon-pair at the Relativistic Heavy Ion Collider

DOE PAGES

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

2017-11-13

The STAR Collaboration reports on the photoproduction of π + π - pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly real photon emitted by one ion scatters from the other ion. In this work, we fit the π + π - invariant-mass spectrum with a combination of ρ 0 and ω resonances and a direct π + π - continuum. This is the first observation of the ω in ultraperipheral collisions, and the first measurement of ρ - ω interference at energies where photoproduction is dominated by Pomeron exchange.more » The ω amplitude is consistent with the measured γp → ωp cross section, a classical Glauber calculation, and the ω → π + π - branching ratio. The ω phase angle is similar to that observed at much lower energies, showing that the ρ - ω phase difference does not depend significantly on photon energy. The ρ 0 differential cross section dσ/dt exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with two minima visible. In conclusion, the positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.« less

Rietveld analysis of X-ray powder diffraction patterns as a potential tool for the identification of impact-deformed carbonate rocks

NASA Astrophysics Data System (ADS)

Huson, S. A.; Foit, F. F.; Watkinson, A. J.; Pope, M. C.

2009-12-01

Previous X-ray powder diffraction (XRD) studies revealed that shock deformed carbonates and quartz have broader XRD patterns than those of unshocked samples. Entire XRD patterns, single peak profiles and Rietveld refined parameters of carbonate samples from the Sierra Madera impact crater, west Texas, unshocked equivalent samples from 95 miles north of the crater and the Mission Canyon Formation of southwest Montana and western Wyoming were used to evaluate the use of X-ray powder diffraction as a potential tool for distinguishing impact deformed rocks from unshocked and tectonically deformed rocks. At Sierra Madera dolostone and limestone samples were collected from the crater rim (lower shock intensity) and the central uplift (higher shock intensity). Unshocked equivalent dolostone samples were collected from well cores drilled outside of the impact crater. Carbonate rocks of the Mission Canyon Formation were sampled along a transect across the tectonic front of the Sevier and Laramide orogenic belts. Whereas calcite subjected to significant shock intensities at the Sierra Madera impact crater can be differentiated from tectonically deformed calcite from the Mission Canyon Formation using Rietveld refined peak profiles, weakly shocked calcite from the crater rim appears to be indistinguishable from the tectonically deformed calcite. In contrast, Rietveld analysis readily distinguishes shocked Sierra Madera dolomite from unshocked equivalent dolostone samples from outside the crater and tectonically deformed Mission Canyon Formation dolomite.

Fibers innovative burning and reuse by Self-propagating High temperature Synthesis (SHS)

NASA Astrophysics Data System (ADS)

Caratto, Valentina; Belfortini, Claudio; Musi, Luigi; Gaggero, Laura; Ferretti, Maurizio

2016-04-01

The treatment of asbestos containing waste deriving from civil building and industrial applications is a social alert and an environmental problem. The project LIFE12 ENV/IT 000295 FIBERS "Fibers innovative burning and reuse by Self-propagating High temperature Synthesis (SHS)" has developed an innovative technique alternative to conventional high T processes. The University of Genoa has developed an apparatus and a technique for triggering the breakdown reaction of chrysotile by means of an alumino-thermic reaction in a process of combustion synthesis well known as Self-propagating High temperature Synthesis or SHS. This approach yielded interesting results and allowed the development of an efficient method for inerting natural asbestos fibers and man-made products carrying fibers at the scale of some grams [1]. The experiments were based on the couples Fe2O3/Mg by implementation of two prototype plants. The varying parameters were: 1) different Asbestos-Containing Waste (ACW) massive (Eternit, linoleum) and friable asbestos; 2) ACW abundance; 3) size of the pellet 4) under two triggering systems (induction by a W coil and oxyacetylene torch). The reactions were carried in two configurations: a) discontinuous, allowed us to obtain data for the development and fine-tuning of the reaction, b) continuous, was indispensable for the development and fine-tuning of the process parameters towards industrial scale up. After the combustive reaction all samples were characterized by SEM-EDS and XRPD analysis. All experiments demonstrated effective in destructing the fibrous habit of chrysotile, turning its composition to stubby olivine grains. We optimized the parameters to achieve complete conversion of the asbestos to mineral grains in all the cases. The efficiency of the SHS reaction in the discontinuous and continuous configurations was highlighted by the characterization of the post-combustion material under SEM-EDS and XRPD that verified the absence of fibers within the limits established by the regulations. The SHS process in comparison with conventional thermal treatments, due to fast reaction time, low activation energy, particularly advantages the asbestos inertization and positively reflects into time and costs of the process. Finally, the product of this transformation is liable to be re-used, e.g. as abrasive, or refractory material; this represents the end of waste status and a second life as secondary raw material. This work was carried out in the frame of LIFE12 ENV/IT/000295 FIBERS co-funded by the European Commission. [1] Gaggero L., Ferretti M., Belfortini C., Isola E. (2010) GE2010A000032

Crystallization kinetics of bioactive glasses in the ZnO-Na2O-CaO-SiO2 system.

PubMed

Malavasi, Gianluca; Lusvardi, Gigliola; Pedone, Alfonso; Menziani, Maria Cristina; Dappiaggi, Monica; Gualtieri, Alessandro; Menabue, Ledi

2007-08-30

The crystallization kinetics of Na(2)O.CaO.2SiO(2) (x = 0) and 0.68ZnO.Na(2)O.CaO.2SiO(2) (x = 0.68, where x is the ZnO stoichiometric coefficient in the glass formula) bioactive glasses have been studied using both nonisothermal and isothermal methods. The results obtained from isothermal XRPD analyses have showed that the first glass crystallizes into the isochemical Na(2)CaSi(2)O(6) phase, whereas the Na(2)ZnSiO(4) crystalline phase is obtained from the Zn-rich glass, in addition to Na(2)CaSi(2)O(6). The activation energy (Ea) for the crystallization of the Na(2)O.CaO.2SiO(2) glass is 193 +/- 10 and 203 +/- 5 kJ/mol from the isothermal in situ XRPD and nonisothermal DSC experiments, respectively. The Avrami exponent n determined from the isothermal method is 1 at low temperature (530 degrees C), and its value increases linearly with temperature increase up to 2 at 607 degrees C. For the crystallization of Na(2)CaSi(2)O(6) from the Zn-containing glass, higher values of both the crystallization temperature (667 and 661 degrees C) and Ea (223 +/- 10 and 211 +/- 5 kJ/mol) have been found from the isothermal and nonisothermal methods, respectively. The Na(2)ZnSiO(4) crystalline phase crystallizes at lower temperature with respect to Na(2)CaSi(2)O(6), and the Ea value is 266 +/- 20 and 245 +/- 15 kJ/mol from the isothermal and nonisothermal methods, respectively. The results of this work show that the addition of Zn favors the crystallization from the glass at lower temperature with respect to the Zn-free glass. In fact, it causes an increase of Ea for the Na diffusion process, determined using MD simulations, and consequently an overall increase of Ea for the crystallization process of Na(2)CaSi(2)O(6). Our results show good agreement between the Ea and n values obtained with the two different methods and confirm the reliability of the nonisothermal method applied to kinetic crystallization of glassy systems. This study allows the determination of the temperature stability field of the crystalline phases with the view of creating a different glass ceramic useful in the field of bioactive materials.

Design and physicochemical characterization of advanced spray-dried tacrolimus multifunctional particles for inhalation

PubMed Central

Wu, Xiao; Hayes, Don; Zwischenberger, Joseph B; Kuhn, Robert J; Mansour, Heidi M

2013-01-01

The aim of this study was to design, develop, and optimize respirable tacrolimus microparticles and nanoparticles and multifunctional tacrolimus lung surfactant mimic particles for targeted dry powder inhalation delivery as a pulmonary nanomedicine. Particles were rationally designed and produced at different pump rates by advanced spray-drying particle engineering design from organic solution in closed mode. In addition, multifunctional tacrolimus lung surfactant mimic dry powder particles were prepared by co-dissolving tacrolimus and lung surfactant mimic phospholipids in methanol, followed by advanced co-spray-drying particle engineering design technology in closed mode. The lung surfactant mimic phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-[phosphor-rac-1-glycerol]. Laser diffraction particle sizing indicated that the particle size distributions were suitable for pulmonary delivery, whereas scanning electron microscopy imaging indicated that these particles had both optimal particle morphology and surface morphology. Increasing the pump rate percent of tacrolimus solution resulted in a larger particle size. X-ray powder diffraction patterns and differential scanning calorimetry thermograms indicated that spray drying produced particles with higher amounts of amorphous phase. X-ray powder diffraction and differential scanning calorimetry also confirmed the preservation of the phospholipid bilayer structure in the solid state for all engineered respirable particles. Furthermore, it was observed in hot-stage micrographs that raw tacrolimus displayed a liquid crystal transition following the main phase transition, which is consistent with its interfacial properties. Water vapor uptake and lyotropic phase transitions in the solid state at varying levels of relative humidity were determined by gravimetric vapor sorption technique. Water content in the various powders was very low and well within the levels necessary for dry powder inhalation, as quantified by Karl Fisher coulometric titration. Conclusively, advanced spray-drying particle engineering design from organic solution in closed mode was successfully used to design and optimize solid-state particles in the respirable size range necessary for targeted pulmonary delivery, particularly for the deep lung. These particles were dry, stable, and had optimal properties for dry powder inhalation as a novel pulmonary nanomedicine. PMID:23403805

Analytical caustic surfaces

NASA Technical Reports Server (NTRS)

Schmidt, R. F.

1987-01-01

This document discusses the determination of caustic surfaces in terms of rays, reflectors, and wavefronts. Analytical caustics are obtained as a family of lines, a set of points, and several types of equations for geometries encountered in optics and microwave applications. Standard methods of differential geometry are applied under different approaches: directly to reflector surfaces, and alternatively, to wavefronts, to obtain analytical caustics of two sheets or branches. Gauss/Seidel aberrations are introduced into the wavefront approach, forcing the retention of all three coefficients of both the first- and the second-fundamental forms of differential geometry. An existing method for obtaining caustic surfaces through exploitation of the singularities in flux density is examined, and several constant-intensity contour maps are developed using only the intrinsic Gaussian, mean, and normal curvatures of the reflector. Numerous references are provided for extending the material of the present document to the morphologies of caustics and their associated diffraction patterns.

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.

Probing the limits of the rigid-intensity-shift model in differential-phase-contrast scanning transmission electron microscopy

NASA Astrophysics Data System (ADS)

Clark, L.; Brown, H. G.; Paganin, D. M.; Morgan, M. J.; Matsumoto, T.; Shibata, N.; Petersen, T. C.; Findlay, S. D.

2018-04-01

The rigid-intensity-shift model of differential-phase-contrast imaging assumes that the phase gradient imposed on the transmitted probe by the sample causes the diffraction pattern intensity to shift rigidly by an amount proportional to that phase gradient. This behavior is seldom realized exactly in practice. Through a combination of experimental results, analytical modeling and numerical calculations, using as case studies electron microscope imaging of the built-in electric field in a p-n junction and nanoscale domains in a magnetic alloy, we explore the breakdown of rigid-intensity-shift behavior and how this depends on the magnitude of the phase gradient and the relative scale of features in the phase profile and the probe size. We present guidelines as to when the rigid-intensity-shift model can be applied for quantitative phase reconstruction using segmented detectors, and propose probe-shaping strategies to further improve the accuracy.

Calcification of MC3T3-E1 cells on titanium and zirconium.

PubMed

Umezawa, Takayuki; Chen, Peng; Tsutsumi, Yusuke; Doi, Hisashi; Ashida, Maki; Suzuki, Shoichi; Moriyama, Keiji; Hanawa, Takao

2015-01-01

To confirm similarity of hard tissue compatibility between titanium and zirconium, calcification of MC3T3-E1 cells on titanium and zirconium was evaluated in this study. Mirror-polished titanium (Ti) and zirconium (Zr) disks and zirconium-sputter deposited titanium (Zr/Ti) were employed in this study. The surface of specimens were characterized using scanning electron microscopy and X-ray diffraction. Then, the cellular proliferation, differentiation and calcification of MC3T3-E1 cells on specimens were investigated. The surface of Zr/Ti was much smoother and cleaner than those of Ti and Zr. The proliferation of the cell was the same among three specimens, while the differentiation and calcification on Zr/Ti were faster than those on Ti and Zr. Therefore, Ti and Zr showed the identical hard tissue compatibility according to the evaluation with MC3T3-E1 cells. Sputter deposition may improve cytocompatibility.

Study of the structural and thermal properties of plasma treated jute fibre

NASA Astrophysics Data System (ADS)

Sinha, E.; Rout, S. K.; Barhai, P. K.

2008-08-01

Jute fibres ( Corchorus olitorius), were treated with argon cold plasma for 5, 10 and 15 min. Structural macromolecular parameters of untreated and plasma treated fibres were investigated using small angle X-ray scattering (SAXS), and the crystallinity parameters of the same fibres were determined by using X-ray diffraction (XRD). Differential scanning calorimetry (DSC) was used to study the thermal behavior of the untreated and treated fibres. Comparison and analysis of the results confirmed the changes in the macromolecular structure after plasma treatment. This is due to the swelling of cellulosic particles constituting the fibres, caused by the bombardment of high energetic ions onto the fibre surface. Differential scanning calorimetry data demonstrated the thermal instability of the fibre after cold plasma treatment, as the thermal degradation temperature of hemicelluloses and cellulose was found lowered than that of raw fibre after plasma treatment.

Speciation of airborne dust from a nickel refinery roasting operation.

PubMed

Andersen, I; Berge, S R; Resmann, F

1998-04-01

Earlier work-related lung and nasal cancer studies included estimates of exposures to different nickel species in the refinery. Based on the metallurgy, only insoluble nickel was believed to be present around the roasters but mixed exposure was assumed in most areas, including the tankhouse. Occasional leaching tests of samples from the roaster area have indicated the presence of soluble nickel. This study reports on five parallel sets of dust samples collected from different floors with standard equipment and treated as follows. Two sets were leached with an ammonium citrate buffer at pH 4.4. Undissolved material was treated with HClO4/HNO3, evaporated to dryness and dissolved in HCl, Ni, Cu, Co, Fe, Se, and As were determined in both fractions. Water soluble Ni was found in all samples, ranging from 5-35%. Sulfate in the solutions correlated nearly stoichiometrically to the total metal content. The three remaining sets were investigated by, respectively, differential leaching, X-ray diffraction and scanning electron microscopy. The percentage of soluble nickel found by differential leaching corresponded well with those obtained by the simplified procedure. X-Ray diffraction analysis showed the presence of NiSO4.6H2O as well as oxides of Ni and Cu. This study indicates mixed exposures also in the roaster area. It also clearly indicates that basing exposure on the metallurgy alone can lead to serious misjudgements. The impact of this new information on the interpretation of cancer incidence at this refinery must await the analysis in an ongoing case-reference study.

Tuning Electrochemical Properties of Li-Rich Layered Oxide Cathodes by Adjusting Co/Ni Ratios and Mechanism Investigation Using in situ X-ray Diffraction and Online Continuous Flow Differential Electrochemical Mass Spectrometry.

PubMed

Shen, ShouYu; Hong, YuHao; Zhu, FuChun; Cao, ZhenMing; Li, YuYang; Ke, FuSheng; Fan, JingJing; Zhou, LiLi; Wu, LiNa; Dai, Peng; Cai, MingZhi; Huang, Ling; Zhou, ZhiYou; Li, JunTao; Wu, QiHui; Sun, ShiGang

2018-04-18

Owing to high specific capacity of ∼250 mA h g -1 , lithium-rich layered oxide cathode materials (Li 1+ x Ni y Co z Mn (3- x-2 y-3 z)/4 O 2 ) have been considered as one of the most promising candidates for the next-generation cathode materials of lithium ion batteries. However, the commercialization of this kind of cathode materials seriously restricted by voltage decay upon cycling though Li-rich materials with high cobalt content have been widely studied and show good capacity. This research successfully suppresses voltage decay upon cycling while maintaining high specific capacity with low Co/Ni ratio in Li-rich cathode materials. Online continuous flow differential electrochemical mass spectrometry (OEMS) and in situ X-ray diffraction (XRD) techniques have been applied to investigate the structure transformation of Li-rich layered oxide materials during charge-discharge process. The results of OEMS revealed that low Co/Ni ratio lithium-rich layered oxide cathode materials released no lattice oxygen at the first charge process, which will lead to the suppression of the voltage decay upon cycling. The in situ XRD results displayed the structure transition of lithium-rich layered oxide cathode materials during the charge-discharge process. The Li 1.13 Ni 0.275 Mn 0.580 O 2 cathode material exhibited a high initial medium discharge voltage of 3.710 and a 3.586 V medium discharge voltage with the lower voltage decay of 0.124 V after 100 cycles.

Effect of niobium content on the microstructure and thermal properties of fluorapatite glass-ceramics.

PubMed

Denry, I L; Holloway, J A; Nakkula, R J; Walters, J D

2005-10-01

Niobium oxide has been shown to improve biocompatibility and promote bioactivity. The purpose of this study was to evaluate the effect of niobium oxide additions on the microstructure and thermal properties of fluorapatite glass-ceramics for biomedical applications. Four glass-ceramic compositions with increasing amounts of niobium oxide from 0 to 5 wt % were prepared. The glass compositions were melted at 1,525 degrees C for 3 h, quenched, ground, melted again at 1,525 degrees C for 3 h and furnace cooled. The coefficient of thermal expansion was measured by dilatometry. The crystallization behavior was evaluated by differential thermal analysis. The nature of the crystalline phases was investigated by X-ray diffraction. The microstructure was studied by SEM. In addition, the cytotoxicity of the ceramics was evaluated according to the ASTM standard F895--84. The results from X-ray diffraction analyses showed that fluorapatite was the major crystalline phase in all glass-ceramics. Differential thermal analyses revealed that fluorapatite crystallization occurred between 800 and 934 degrees C depending on the composition. The coefficient of thermal expansion varied from 7.6 to 9.4 x 10(-6)/ degrees C. The microstructure after heat treatment at 975 degrees C for 30 min consisted of submicroscopic fluorapatite crystals (200--300 nm) for all niobium-containing glass-ceramics, whereas the niobium-free glass-ceramic contained needle-shaped fluorapatite crystals, 2 microm in length. None of the glass-ceramics tested exhibited any cytotoxic activity as tested by ASTM standard F895--84. (c) 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005.

Phenoxo bridged dinuclear Zn(II) Schiff base complex as new precursor for preparation zinc oxide nanoparticles: Synthesis, characterization, crystal structures and photoluminescence studies

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

Saeednia, S., E-mail: sami_saeednia@yahoo.com; Iranmanesh, P.; Ardakani, M. Hatefi

Highlights: • A novel nano-scale Zn(II) complex was synthesized by solvothermal method. • Chemical structure of the nanostructures was characterized as well as bulk complex. • The photoluminescence property of the complex was investigated at room temperature. • The thermogravimetry and differential thermal analysis were carried out. • Thermal decomposition of the nanostructures was prepared zinc oxide nanoparticles. - Abstract: Nanoparticles of a novel Zn(II) Schiff base complex, [Zn(HL)NO{sub 3}]{sub 2} (1), (H{sub 2}L = 2-[(2-hydroxy-propylimino) methyl] phenol), was synthesized by using solvothermal method. Shape, morphology and chemical structure of the synthesized nanoparticles were characterized by scanning electron microscopy (SEM),more » X-ray powder diffraction (XRD), Fourier Transform Infrared Spectoscopy (FT-IR) and UV–vis spectroscopy. Structural determination of compound 1 was determined by single-crystal X-ray diffraction. The results were revealed that the zinc complex is a centrosymmetric dimer in which deprotonated phenolates bridge the two five-coordinate metal atoms and link the two halves of the dimer. The thermal stability of compound 1 was analyzed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of the initial substrates concentration and reaction time on size and morphology of compound 1 nanostructure was investigated as well. Furthermore, the luminescent properties of the complex 1 were examined. ZnO nanoparticles with diameter between 15 and 20 nm were simply synthesized by solid-state transformation of compound 1 at 700 °C.« less

Tracking mechanical Dauphiné twin evolution with applied stress in axial compression experiments on a low-grade metamorphic quartzite

NASA Astrophysics Data System (ADS)

Minor, Alexander; Rybacki, Erik; Sintubin, Manuel; Vogel, Sven; Wenk, Hans-Rudolf

2018-07-01

The stress-dependent evolution of mechanical Dauphiné twinning has been investigated in axial compression experiments on a low-grade metamorphic quartzite, applying both time-of-flight neutron diffraction and electron backscatter diffraction. The data of the experimentally stressed quartzite samples were compared with those of the naturally deformed starting material to monitor Dauphiné twinning in relation to different experimental stress states. This comparison shows that in the experimental conditions of 500 °C temperature and 300 MPa confining pressure, Dauphiné twinning initiates below 145 MPa differential stress and saturates between 250 MPa and 460 MPa differential stress. A single grain orientation analysis (SGOA) has been developed based on the distinction of quartz grains free of Dauphiné twin boundaries (DTBs) and containing Dauphiné twin boundaries. Comparing pole figures and inverse pole figures of DTB-free grains of the starting material with those of the experimentally stressed samples shows a significantly different orientation distribution of the positive {10 1 bar 1} (r) and the negative {01 1 bar 1} (z) rhombs. In DTB-containing grains, the SGOA allows to distinguish between host and twin domains. Using DTB-free grains, the SGOA furthermore reveals a particular pattern, with one of the r rhomb maxima parallel to the axial compressive stress direction and a girdle with two r rhomb submaxima perpendicular to it. We believe that this relationship between the axial compressive stress direction and the rhomb orientation distribution shows the potential of the SGOA in the reconstruction of the paleostress state in naturally stressed quartz-bearing rocks.

Dual functions of silver nanoparticles in F9 teratocarcinoma stem cells, a suitable model for evaluating cytotoxicity- and differentiation-mediated cancer therapy.

PubMed

Han, Jae Woong; Gurunathan, Sangiliyandi; Choi, Yun-Jung; Kim, Jin-Hoi

2017-01-01

Silver nanoparticles (AgNPs) exhibit strong antibacterial and anticancer activity owing to their large surface-to-volume ratios and crystallographic surface structure. Owing to their various applications, understanding the mechanisms of action, biological interactions, potential toxicity, and beneficial effects of AgNPs is important. Here, we investigated the toxicity and differentiation-inducing effects of AgNPs in teratocarcinoma stem cells. AgNPs were synthesized and characterized using various analytical techniques such as UV-visible spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The cellular responses of AgNPs were analyzed by a series of cellular and biochemical assays. Gene and protein expressions were analyzed by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The AgNPs showed typical crystalline structures and spherical shapes (average size =20 nm). High concentration of AgNPs induced cytotoxicity in a dose-dependent manner by increasing lactate dehydrogenase leakage and reactive oxygen species. Furthermore, AgNPs caused mitochondrial dysfunction, DNA fragmentation, increased expression of apoptotic genes, and decreased expression of antiapoptotic genes. Lower concentrations of AgNPs induced neuronal differentiation by increasing the expression of differentiation markers and decreasing the expression of stem cell markers. Cisplatin reduced the viability of F9 cells that underwent AgNPs-induced differentiation. The results showed that AgNPs caused differentially regulated cytotoxicity and induced neuronal differentiation of F9 cells in a concentration-dependent manner. Therefore, AgNPs can be used for differentiation therapy, along with chemotherapeutic agents, for improving cancer treatment by targeting specific chemotherapy-resistant cells within a tumor. Furthermore, understanding the molecular mechanisms of apoptosis and differentiation in stem cells could also help in developing new strategies for cancer stem cell (CSC) therapies. The findings of this study could significantly contribute to the nanomedicine because this study is the first of its kind, and our results will lead to new strategies for cancer and CSC therapies.

Physicochemical characterization of tacrolimus-loaded solid dispersion with sodium carboxylmethyl cellulose and sodium lauryl sulfate.

PubMed

Park, Young-Joon; Ryu, Dong-Sung; Li, Dong Xun; Quan, Qi Zhe; Oh, Dong Hoon; Kim, Jong Oh; Seo, Youn Gee; Lee, Young-Im; Yong, Chul Soon; Woo, Jong Soo; Choi, Han-Gon

2009-06-01

To develop a novel tacrolimus-loaded solid dispersion with improved solubility, various solid dispersions were prepared with various ratios of water, sodium lauryl sulfate, citric acid and carboxylmethylcellulose-Na using spray drying technique. The physicochemical properties of solid dispersions were investigated using scanning electron microscopy, differential scanning calorimetery and powder X-ray diffraction. Furthermore, their solubility and dissolution were evaluated compared to drug powder. The solid dispersion at the tacrolimus/CMC-Na/sodium lauryl sulfate/citric acid ratio of 3/24/3/0.2 significantly improved the drug solubility and dissolution compared to powder. The scanning electron microscopy result suggested that carriers might be attached to the surface of drug in this solid dispersion. Unlike traditional solid dispersion systems, the crystal form of drug in this solid dispersion could not be converted to amorphous form, which was confirmed by the analysis of DSC and powder X-ray diffraction. Thus, the solid dispersion system with water, sodium lauryl sulfate, citric acid and CMC-Na should be a potential candidate for delivering a poorly water-soluble tacrolimus with enhanced solubility and no convertible crystalline.

Synthesis, growth, structural characterization, Hirshfeld analysis and nonlinear optical studies of a methyl substituted chalcone

NASA Astrophysics Data System (ADS)

Prabhu, Shobha R.; Jayarama, A.; Chandrasekharan, K.; Upadhyaya, V.; Ng, Seik Weng

2017-05-01

A new chalcone compound (2E)-3-(3-methylphenyl)-1-(4-nitrophenyl)prop-2-en-1-one (3MPNP) with molecular formula C16H13NO3 has been synthesized and crystallized by slow solvent evaporation technique. The Fourier transform infrared, Fourier transform Raman and nuclear magnetic resonance techniques were used for structural characterization. UV-visible absorption studies were carried out to study the transparency of the crystal in the visible region. Differential scanning calorimetry study shows thermal stability of crystals up to temperature 122 °C. Single crystal X-ray diffraction and powder X-ray diffraction techniques were used to study crystal structure and cell parameters. The Hirshfeld surface and 2-D fingerprint analysis were performed to study the nature of interactions and their quantitative contributions towards the crystal packing. The third order non-linear optical properties have been studied using single beam Z-scan technique and the results show that the material is a potential candidate for optical device applications such as optical limiters and optical switches.

Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D

DOE PAGES

Guo, Y.; Collins, D. M.; Tarleton, E.; ...

2015-06-24

The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished throughmore » the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.« less

Liquid structure of dibutyl sulfoxide

DOE PAGES

Lo Celso, Fabrizio; Aoun, Bachir; Triolo, Alessandro; ...

2016-05-16

We present experimental (x-ray diffraction) data on the structure of liquid dibutyl sulfoxide at 320 K and rationalize them by means of Molecular Dynamics simulations. Not unexpectedly, DBSO bearing a strong dipolar moiety and two medium length, apolar, butyl chains, this compound turns out to be characterised by a distinct degree of polar-vs-apolar structural differentiation at the nm spatial scale that is fingerprinted in a low Q peak in its x-ray diffraction pattern. Similarly to, but to a larger extent than its shorter chain family members (such as DMSO), DBSO is also characterised by an enhanced dipole-dipole correlation that ismore » responsible for the moderate Kirkwood correlation factor as well as for the self-association detected in this compound. In conclusion, we show however that the supposedly relevant hydrogen bonding correlations between oxygen and butyl chain hydrogens are of limited extent and only in the case of α-hydrogens appreciable indication of the existence of such an interaction is found, but it turns out to be a mere consequence of the strong dipole-dipole correlation.« less

ACCURATE MODELING OF X-RAY EXTINCTION BY INTERSTELLAR GRAINS

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

Hoffman, John; Draine, B. T., E-mail: jah5@astro.princeton.edu, E-mail: draine@astro.princeton.edu

Interstellar abundance determinations from fits to X-ray absorption edges often rely on the incorrect assumption that scattering is insignificant and can be ignored. We show instead that scattering contributes significantly to the attenuation of X-rays for realistic dust grain size distributions and substantially modifies the spectrum near absorption edges of elements present in grains. The dust attenuation modules used in major X-ray spectral fitting programs do not take this into account. We show that the consequences of neglecting scattering on the determination of interstellar elemental abundances are modest; however, scattering (along with uncertainties in the grain size distribution) must bemore » taken into account when near-edge extinction fine structure is used to infer dust mineralogy. We advertise the benefits and accuracy of anomalous diffraction theory for both X-ray halo analysis and near edge absorption studies. We present an open source Fortran suite, General Geometry Anomalous Diffraction Theory (GGADT), that calculates X-ray absorption, scattering, and differential scattering cross sections for grains of arbitrary geometry and composition.« less

Multimodal Spectral Imaging of Cells Using a Transmission Diffraction Grating on a Light Microscope

PubMed Central

Isailovic, Dragan; Xu, Yang; Copus, Tyler; Saraswat, Suraj; Nauli, Surya M.

2011-01-01

A multimodal methodology for spectral imaging of cells is presented. The spectral imaging setup uses a transmission diffraction grating on a light microscope to concurrently record spectral images of cells and cellular organelles by fluorescence, darkfield, brightfield, and differential interference contrast (DIC) spectral microscopy. Initially, the setup was applied for fluorescence spectral imaging of yeast and mammalian cells labeled with multiple fluorophores. Fluorescence signals originating from fluorescently labeled biomolecules in cells were collected through triple or single filter cubes, separated by the grating, and imaged using a charge-coupled device (CCD) camera. Cellular components such as nuclei, cytoskeleton, and mitochondria were spatially separated by the fluorescence spectra of the fluorophores present in them, providing detailed multi-colored spectral images of cells. Additionally, the grating-based spectral microscope enabled measurement of scattering and absorption spectra of unlabeled cells and stained tissue sections using darkfield and brightfield or DIC spectral microscopy, respectively. The presented spectral imaging methodology provides a readily affordable approach for multimodal spectral characterization of biological cells and other specimens. PMID:21639978

Identification of New Cocrystal Systems with Stoichiometric Diversity of Salicylic Acid Using Thermal Methods.

PubMed

Zhou, Zhengzheng; Chan, Hok Man; Sung, Herman H-Y; Tong, Henry H Y; Zheng, Ying

2016-04-01

The purpose of this work was to develop thermal methods to identify cocrystal systems with stoichiometric diversity. Differential scanning calorimetry (DSC) and hot stage microscopy (HSM) have been applied to study the stoichiometric diversity phenomenon on cocrystal systems of the model compound salicylic acid (SA) with different coformers (CCFs). The DSC method was particularly useful in the identification of cocrystal re-crystallization, especially to improve the temperature resolution using a slower heating rate. HSM was implemented as a complementary protocol to confirm the DSC results. The crystal structures were elucidated by single-crystal X-ray diffraction (SXRD). Two new cocrystal systems consisting of salicylic acid-benzamide (SA-BZD, 1:1, 1:2) and salicylic acid-isonicotinamide (SA-ISN, 1:1, 2:1) have been identified in the present work. The chemical structures of the newly discovered cocrystals SA-BZD (1:2) and SA-ISN (2:1) have been elucidated using X-ray single crystal and powder diffraction methods. The developed thermal methods could rapidly identify cocrystal systems with stoichiometric diversity, with the potential to discover new pharmaceutical cocrystals in the future.

A novel structure of gel grown strontium cyanurate crystal and its structural, optical, electrical characterization

NASA Astrophysics Data System (ADS)

Divya, R.; Nair, Lekshmi P.; Bijini, B. R.; Nair, C. M. K.; Gopakumar, N.; Babu, K. Rajendra

2017-12-01

Strontium cyanurate crystals with novel structure and unique optical property like mechanoluminescence have been grown by conventional gel method. Transparent crystals were obtained. The single crystal X-ray diffraction analysis reveals the exquisite structure of the grown crystal. The crystal is centrosymmetric and has a three dimensional polymeric structure. The powder X ray diffraction analysis confirms its crystalline nature. The functional groups present in the crystal were identified by Fourier transform infrared spectroscopy. Elemental analysis confirmed the composition of the complex. A study of thermal properties was done by thermo gravimetric analysis and differential thermal analysis. The optical properties like band gap, refractive index and extinction coefficient were evaluated from the UV visible spectral analysis. The etching study was done to reveal the dislocations in the crystal which in turn explains mechanoluminescence emission. The mechanoluminescence property exhibited by the crystal makes it suitable for stress sensing applications. Besides being a centrosymmetric crystal, it also exhibits NLO behavior. Dielectric properties were studied and theoretical calculations of Fermi energy, valence electron plasma energy, penn gap and polarisability have been done.

FTIR spectroscopic, thermal and XRD characterization of hydroxyapatite from new natural sources

NASA Astrophysics Data System (ADS)

Shaltout, Abdallah A.; Allam, Moussa A.; Moharram, Mohamed A.

2011-12-01

The inorganic constituents of 5 different plants (leaves and stalks) were investigated by using Fourier transformer infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal analysis including thermal gravimetric analysis (TGA), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). These plants are Catha edulis (Khat), basil, mint, green tea and trifolium. The absorption bands of carbonate ions CO 32- was exhibited at 1446 cm -1, and the phosphate ions PO 43- was assigned at 1105 and 1035 cm -1. At high temperatures (600, 700 and 600 °C) further absorption bands of the phosphate ions PO 43- was assigned at the frequencies 572, 617, 962, 1043 and 1110 cm -1 and the vibrational absorption band of the carbonate ions CO 32- was assigned at 871, 1416 and 1461 cm -1. X-ray diffraction and thermal analysis confirm the obtained results of FITR. Results showed that the main inorganic constituents of C. edulis and basil leaves are hydroxyapatite whereas the hydroxyapatite content in the other plant samples is less than that in case of C. edulis and basil plant leaves.

Synthesis and structural characterization of CdS nanoparticles

NASA Astrophysics Data System (ADS)

Kotkata, M. F.; Masoud, A. E.; Mohamed, M. B.; Mahmoud, E. A.

2009-08-01

Amorphous CdS nanoparticles capped with cetyltrimethyl ammonium bromide (CTAB) were synthesised under various conditions using a coprecipitation method. A blue shift in the band gap was observed in the UV-visible absorption spectra indicating the formation of nanoparticles of an approximate size of 8 nm. The recorded transmission electron micrographs confirmed this result. The phase-nature, phase transformation as well as the structure of the synthesised CdS nanoparticles have been extensively characterized using X-ray diffraction (XRD), radial distribution function (RDF), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Raman scattering (RS) and/or heat stage X-ray diffraction (HSXRD). Analysis of the obtained results revealed that the synthesised amorphous CdS nanoparticles could be transformed into CdS nanocrystals having a zinc blende or a wurtzite structure, relying on the applied heat treatment scheme. The rate of nanocrystal growth depends on the aging period, prior filtering the reacted materials, and its relation to the quality of the capping process. Five days aging period tends to enhance the stability of the grown phase with a remarkable surface stability.

A micromachined membrane-based active probe for biomolecular mechanics measurement

NASA Astrophysics Data System (ADS)

Torun, H.; Sutanto, J.; Sarangapani, K. K.; Joseph, P.; Degertekin, F. L.; Zhu, C.

2007-04-01

A novel micromachined, membrane-based probe has been developed and fabricated as assays to enable parallel measurements. Each probe in the array can be individually actuated, and the membrane displacement can be measured with high resolution using an integrated diffraction-based optical interferometer. To illustrate its application in single-molecule mechanics experiments, this membrane probe was used to measure unbinding forces between L-selectin reconstituted in a polymer-cushioned lipid bilayer on the probe membrane and an antibody adsorbed on an atomic force microscope cantilever. Piconewton range forces between single pairs of interacting molecules were measured from the cantilever bending while using the membrane probe as an actuator. The integrated diffraction-based optical interferometer of the probe was demonstrated to have <10 fm Hz-1/2 noise floor for frequencies as low as 3 Hz with a differential readout scheme. With soft probe membranes, this low noise level would be suitable for direct force measurements without the need for a cantilever. Furthermore, the probe membranes were shown to have 0.5 µm actuation range with a flat response up to 100 kHz, enabling measurements at fast speeds.

Crystal structure and thermal expansion of a CsCe 2Cl 7 scintillator

DOE PAGES

Zhuravleva, M.; Lindsey, A.; Chakoumakos, B. C.; ...

2015-04-06

Here we used single-crystal X-ray diffraction data to determine crystal structure of CsCe 2Cl 7. It crystallizes in a P112 1/b space group with a = 19.352(1) Å, b = 19.352(1) Å, c = 14.838(1) Å, γ = 119.87(2) ° , and V = 4818.6(5) Å 3. Differential scanning calorimetry measurements combined with the structural evolution of CsCe 2Cl 7 via X-ray diffractometry over a temperature range from room temperature to the melting point indicates no obvious intermediate solid-solid phase transitions. The anisotropy in the average linear coefficient of thermal expansion of the a axis (21.3 10 -6/ °C) withmore » respect to the b and c axes (27.0 10 -6/ °C) was determined through lattice parameter refinement of the temperature dependent diffraction patterns. Lastly, these findings suggest that the reported cracking behavior during melt growth of CsCe 2Cl 7 bulk crystals using conventional Bridgman and Czochralski techniques may be largely attributed to the anisotropy in thermal expansion.« less

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

Ito, Yuta; Wang, Chuncheng; Le, Anh-Thu

Here, we have measured the angular distributions of high energy photoelectrons of benzene molecules generated by intense infrared femtosecond laser pulses. These electrons arise from the elastic collisions between the benzene ions with the previously tunnel-ionized electrons that have been driven back by the laser field. Theory shows that laser-free elastic differential cross sections (DCSs) can be extracted from these photoelectrons, and the DCS can be used to retrieve the bond lengths of gas-phase molecules similar to the conventional electron diffraction method. From our experimental results, we have obtained the C-C and C-H bond lengths of benzene with a spatialmore » resolution of about 10 pm. Our results demonstrate that laser induced electron diffraction (LIED) experiments can be carried out with the present-day ultrafast intense lasers already. Looking ahead, with aligned or oriented molecules, more complete spatial information of the molecule can be obtained from LIED, and applying LIED to probe photo-excited molecules, a “molecular movie” of the dynamic system may be created with sub-A°ngstrom spatial and few-ten femtosecond temporal resolutions.« less

Mechanically activated synthesis of PZT and its electromechanical properties

NASA Astrophysics Data System (ADS)

Liu, X.; Akdogan, E. K.; Safari, A.; Riman, R. E.

2005-08-01

Mechanical activation was successfully used to synthesize nanostructured phase-pure Pb(Zr0.7Ti0.3)O3 (PZT) powders. Lead zirconium titanium (PbZrTi) hydrous oxide precursor, synthesized from chemical co-precipitation, was mechanically activated in a NaCl matrix. The synthesized PZT particles were characterized by using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, laser-light diffraction, and nitrogen adsorption. Thermogravimetric analysis and differential thermal analysis were used to monitor dehydration and phase transformation of PbZrTi hydrous oxide precursor during mechanical activation. The best mechanical activation conditions corresponded to mechanically activating PbZrTi hydrous oxide precursor in a NaCl matrix with a NaCl/precursor weight ratio of 4:1 for 8 h. These conditions resulted in a dispersible phase-pure PZT powder with a median secondary-particle size of ˜110 nm. The properties of PZT 70/30 from mechanically activated powder, as measured on discs sintered at 1150 °C for 2 h, were found to be in close conformity to those obtained by a conventional mixed oxide solid state reaction route.

Crystal growth, structural, optical, spectral and thermal studies of tris( L-phenylalanine) L-phenylalaninium nitrate: A new organic nonlinear optical material

NASA Astrophysics Data System (ADS)

Prakash, M.; Geetha, D.; Lydia Caroline, M.

2011-10-01

Tris( L-phenylalanine) L-phenylalaninium nitrate, C 9H 12NO 2+·NO 3-·3C 9H 11NO 2 (TPLPN), a new organic nonlinear optical material was grown from aqueous solution by slow evaporation solution growth at room temperature. The grown crystals were subjected to powder X-ray diffraction and single crystal X-ray diffraction studies to confirm the crystalline nature and crystal structure. The modes of vibration of different molecular groups present in TPLPN have been identified by FTIR spectral analysis. The presence of hydrogen and carbon in the grown crystal were confirmed by using proton and carbon nuclear magnetic resonance (NMR) spectral analyses. The optical transmission spectral study establishes good transmitting ability of the crystal in the entire visible region. The thermogravimetric (TG) and differential thermal analyses (DTA) were carried out to understand the thermal stability of the sample. The nonlinear optical property of the compound observed using Kurtz powder second harmonic generation test assets the suitability of the grown material for the frequency conversion of laser radiation of Nd:YAG.

Cocrystals of acyclovir with promising physicochemical properties.

PubMed

Sarkar, Anindita; Rohani, Sohrab

2015-01-01

Cocrystal forming ability of antiviral drug acyclovir (ACV) with different coformers was studied. Three cocrystals containing ACV with fumaric acid, malonic acid, and DL-tartaric acid were isolated. Methods of cocrystallization included grinding with dropwise solvent addition and solvent evaporation. The cocrystals were characterized by powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The crystal structure of the cocrystal with fumaric acid as conformer was determined by single crystal X-ray diffraction. Formation of supramolecular synthon was observed in the cocrystal. Stability with respect to relative humidity for the three cocrystals was evaluated. The aqueous solubility of the ACV-cocrystal materials was significantly improved with a maximum of malonic acid cocrystal, which was about six times more soluble at 35°C compared with that of parent ACV. The dissolution profile indicates that at any particular dissolution time, the concentration of cocrystals in the solution was higher than that of the parent ACV, and malonic acid cocrystals had a maximum release of about twice than the hydrated ACV. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Interfacial reflection enhanced optical extinction and thermal dynamics in polymer nanocomposite films

NASA Astrophysics Data System (ADS)

Dunklin, Jeremy R.; Forcherio, Gregory T.; Berry, Keith R.; Roper, D. Keith

2016-09-01

Polymer films containing plasmonic nanostructures are of increasing interest for development of responsive energy, sensing, and therapeutic systems. A series of novel gold nanoparticle (AuNP)-polydimethylsiloxane (PDMS) films were fabricated to elucidate enhanced optical extinction from diffractive and scattering induced internal reflection. AuNPs with dramatically different scattering-to-absorption ratios were compared at variable interparticle separations to differentiate light trapping from optical diffraction and Mie scattering. Description of interfacial optical and thermal effects due to these interrelated contributions has progressed beyond Mie theory, Beer's law, effective media, and conventional heat transfer descriptions. Thermal dissipation rates in AuNP-PDMS with this interfacial optical reflection was enhanced relative to films containing heterogeneous AuNPs and a developed thermal dissipation description. This heuristic, which accounts for contributions of both internal and external thermal dissipations, has been shown to accurately predict thermal dissipation rates from AuNP-containing insulating and conductive substrates in both two and three-dimensional systems. Enhanced thermal response rates could enable design and adaptive control of thermoplasmonic materials for a variety of implementations.

Direct structural evidence of commensurate-to-incommensurate transition of hydrocarbon adsorption in a microporous metal organic framework

DOE PAGES

Banerjee, Debasis; Wang, Hao; Gong, Qihan; ...

2015-10-27

Here, the efficiency of physisorption-based separation of gas-mixtures depends on the selectivity of adsorbent which is directly linked to size, shape, polarizability and other physical properties of adsorbed molecules. Commensurate adsorption is an interesting and important adsorption phenomenon, where the adsorbed amount, location, and orientation of an adsorbate are commensurate with the crystal symmetry of the adsorbent. Understanding this phenomenon is important and beneficial as it can provide vital information about adsorbate–adsorbent interaction and adsorption–desorption mechanism. So far, only sporadic examples of commensurate adsorption have been reported in porous materials such as zeolites and metal organic frameworks (MOFs). In thismore » work we show for the first time direct structural evidence of commensurate-to-incommensurate transition of linear hydrocarbon molecules (C 2–C7) in a microporous MOF, by employing a number of analytical techniques including single crystal X-ray diffraction (SCXRD), in situ powder X-ray diffraction coupled with differential scanning calorimetry (PXRD-DSC), gas adsorption and molecular simulations.« less

Synthesis and characterization of nano TiO2-SiO2: PVA composite - a novel route

NASA Astrophysics Data System (ADS)

Venckatesh, Rajendran; Balachandaran, Kartha; Sivaraj, Rajeshwari

2012-07-01

A novel, simple, less time consuming and cost-effective sol-gel method has been developed to synthesize nano titania-silica with polyvinyl alcohol (PVA) composite relatively at low temperature in acidic pH. Titania sol is prepared by hydrolysis of titanium tetrachloride and was mixed with silicic acid and tetrahydrofuran mixture. The reaction was carried out under vigorous stirring for 6 h and dried at room temperature with the addition of PVA solution. The resulting powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FT-IR), UV-visible spectroscopy and thermal techniques. The grain size of the particles was calculated by X-ray diffraction; surface morphology and chemical composition were determined from scanning electron microscopy-energy dispersive spectroscopy; metal oxide stretching was confirmed from FT-IR spectroscopy; bandgap was calculated using UV-visible spectroscopy, and thermal stability of the prepared composite was determined by thermogravimetric/differential thermal analysis. Since TiO2 got agglomerated on the surface of SiO2, effective absorptive sites increase which in turn increase the photocatalytic efficiency of the resulting composite.

A simple 2D composite image analysis technique for the crystal growth study of L-ascorbic acid.

PubMed

Kumar, Krishan; Kumar, Virender; Lal, Jatin; Kaur, Harmeet; Singh, Jasbir

2017-06-01

This work was destined for 2D crystal growth studies of L-ascorbic acid using the composite image analysis technique. Growth experiments on the L-ascorbic acid crystals were carried out by standard (optical) microscopy, laser diffraction analysis, and composite image analysis. For image analysis, the growth of L-ascorbic acid crystals was captured as digital 2D RGB images, which were then processed to composite images. After processing, the crystal boundaries emerged as white lines against the black (cancelled) background. The crystal boundaries were well differentiated by peaks in the intensity graphs generated for the composite images. The lengths of crystal boundaries measured from the intensity graphs of composite images were in good agreement (correlation coefficient "r" = 0.99) with the lengths measured by standard microscopy. On the contrary, the lengths measured by laser diffraction were poorly correlated with both techniques. Therefore, the composite image analysis can replace the standard microscopy technique for the crystal growth studies of L-ascorbic acid. © 2017 Wiley Periodicals, Inc.

x-y curvature wavefront sensor.

PubMed

Cagigal, Manuel P; Valle, Pedro J

2015-04-15

In this Letter, we propose a new curvature wavefront sensor based on the principles of optical differentiation. The theoretically modeled setup consists of a diffractive optical mask placed at the intermediate plane of a classical two-lens coherent optical processor. The resulting image is composed of a number of local derivatives of the entrance pupil function whose proper combination provides the wavefront curvature. In contrast to the common radial curvature sensors, this one is able to provide the x and y wavefront curvature maps simultaneously. The sensor offers other additional advantages like having high spatial resolution, adjustable dynamic range, and not being sensitive to misalignment.

Synthesis and Characterization of the First Liquid Single Source Precursors for the Deposition of Ternary Chalcopyrite (CuInS2) Thin Film Materials

NASA Technical Reports Server (NTRS)

Banger, Kulbinder K.; Cowen, Jonathan; Hepp, Aloysius

2002-01-01

Molecular engineering of ternary single source precursors based on the [{PBu3}2Cu(SR')2In(SR')2] architecture have afforded the first liquid CIS ternary single source precursors (when R = Et, n-Pr), which are suitable for low temperature deposition (< 350 C). Thermogravimetric analyses (TGA) and modulated-differential scanning calorimetry (DSC) confirm their liquid phase and reduced stability. X-ray diffraction studies, energy dispersive analyzer (EDS), and scanning electron microscopy (SEM) support the formation of the single-phase chalcopyrite CuInS2 at low temperatures.

Helium Atom Scattering from C2H6, F2HCCH3, F3CCH2F and C2F6 in Crossed Molecular Beams

NASA Astrophysics Data System (ADS)

Hammer, Markus; Seidel, Wolfhart

1997-10-01

Rotationally unresolved differential cross sections were measured in crossed molecular beam experiments by scattering Helium atoms from Ethane, 1,1-Difluoroethane, 1,1,1,2-Tetrafluoroethane and Hexafluoroethane. The damping of observed diffraction oscillations was used to extract anisotropic interaction potentials for these scattering systems applying the infinite order sudden approximation (IOSA). Binary macroscopic parameters such as second heterogeneous virial coefficients and the coefficients of diffusion and viscosity were computed from these potentials and compared to results from macroscopic experiments.

Crystal growth, structure analysis and characterisation of 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid single crystal

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

Sankari, R. Siva, E-mail: sivasankari.sh@act.edu.in; Perumal, Rajesh Narayana

2014-04-24

Single crystal of dielectric material 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid has been grown by slow evaporation solution growth method. The grown crystal was harvested in 25 days. The crystal structure was analyzed by Single crystal X - ray diffraction. UV-vis-NIR analysis was performed to examine the optical property of the grown crystal. The thermal property of the grown crystal was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The dielectric measurements were carried out and the dielectric constant was calculated and plotted at all frequencies.

Nm-scale spatial resolution x-ray imaging with MLL nanofocusing optics: instrumentational requirements and challenges

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

Nazaretski, E.; Yan, H.; Lauer, K.

2016-08-30

The Hard X-ray Nanoprobe (HXN) beamline at NSLS-II has been designed and constructed to enable imaging experiments with unprecedented spatial resolution and detection sensitivity. The HXN X-ray Microscope is a key instrument for the beamline, providing a suite of experimental capabilities which includes scanning fluorescence, diffraction, differential phase contrast and ptychography utilizing Multilayer Laue Lenses (MLL) and zoneplate (ZP) as nanofocusing optics. In this paper, we present technical requirements for the MLL-based scanning microscope, outline the development concept and present first ~15 x 15 nm 2 spatial resolution x-ray fluorescence images.

Preparation and Characterization of Cabamazepine Cocrystal in Polymer Solution.

PubMed

Zhang, Hao; Zhu, Ying; Qiao, Ning; Chen, Yang; Gao, Linghuan

2017-12-01

In this study, we attempted to prepare carbamazepine (CBZ) cocrystal through the solution method in ethanol-water solvent mixture (volume ratio 1:1) and polyvinyl pyrrolidone (PVP) solution. Nicotinamide (NIC) and saccharin (SAC) were selected as cocrystal coformers. Cocrystal screening products were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Powder X-ray Diffraction (PXRD) techniques. Characterization results show that in ethanol-water solvent mixture, pure CBZ-NIC cocrystal can be prepared, while CBZ-SAC cocrystal cannot be obtained. The addition of PVP can inhibit CBZ-NIC cocrystal formation and facilitate CBZ-SAC cocrystal formation.

Preparation and Characterization of Carbamazepine Cocrystal in Polymer Solution

PubMed Central

Zhang, Hao; Zhu, Ying; Chen, Yang; Gao, Linghuan

2017-01-01

In this study, we attempted to prepare carbamazepine (CBZ) cocrystal through the solution method in ethanol-water solvent mixture (volume ratio 1:1) and polyvinyl pyrrolidone (PVP) solution. Nicotinamide (NIC) and saccharin (SAC) were selected as cocrystal coformers. Cocrystal screening products were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Powder X-ray Diffraction (PXRD) techniques. Characterization results show that in ethanol-water solvent mixture, pure CBZ-NIC cocrystal can be prepared, while CBZ-SAC cocrystal cannot be obtained. The addition of PVP can inhibit CBZ-NIC cocrystal formation and facilitate CBZ-SAC cocrystal formation. PMID:29194387

Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals

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

Govindaiah, T. N., E-mail: tngovi.phy@gmail.com; Sreepad, H. R.; Sridhar, K. N.

2015-06-24

A binary mixture of abietic acid and orthophosphoric acid (H{sub 3}PO{sub 4}) exhibits co-existence of biphasic region of Nematic+Isotropic (N+I), lyotropic Nematic (ND) and Smectic-G (SmG) phases. The mixture exhibits N+I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I→N+I→N→SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.

Polyamideimides containing carbonyl and ether connecting groups

NASA Technical Reports Server (NTRS)

Havens, S. J.; Hergenrother, P. M.

1990-01-01

Polyamidenimides were prepared from the reaction of trimellitic anhydride chloride with seven diamines containing carbonyl and ether groups between the aromatic rings. Several of these polyamideimides were semicrystalline as evidenced by wide-angle X-ray diffraction and differential scanning calorimetry. Glass transition temperatures ranged between 187 and 245 C, and crystalline transition temperatures ranged between 317 and 416 C. A series of copolyamideimides from a mixture of 1,3-bis(4-aminophenoxy 4-prime-benzoyl) benzene and 1,4-bis(4-aminophenoxy 4-prime-benzoyl)benzene were similarly prepared. These copolyamideimides were semicrystalline and formed tough, solvent resistant films with good tensile properties.

Investigation of selected structural parameters in Fe 95Si 5 amorphous alloy during crystallization process

NASA Astrophysics Data System (ADS)

Fronczyk, Adam

2007-04-01

In this study, we report on a crystallization behavior of the Fe 95Si 5 metallic glasses using a differential scanning cabrimetry (DSC), and X-ray diffraction. The paper presents the results of experimental investigation of Fe 95Si 5 amorphous alloy, subjected to the crystallizing process by the isothermal annealing. The objective of the experiment was to determine changes in the structural parameters during crystallization process of the examined alloy. Crystalline diameter and the lattice constant of the crystallizing phase were used as parameters to evaluate structural changes in material.

Study of Carbide Evolution During Thermo-Mechanical Processing of AISI D2 Tool Steel

NASA Astrophysics Data System (ADS)

Bombac, D.; Fazarinc, M.; Podder, A. Saha; Kugler, G.

2013-03-01

The microstructure of a cold-worked tool steel (AISI D2) with various thermo-mechanical treatments was examined in the current study to identify the effects of these treatments on phases. X-ray diffraction was used to identify phases. Microstructural changes such as spheroidization and coarsening of carbides were studied. Thermodynamic calculations were used to verify the results of the differential thermal analysis. It was found that soaking temperature and time have a large influence on dissolution, precipitation, spheroidization, and coalescence of carbides present in the steel. This consequently influences the hot workability and final properties.

Phase transformations during the growth of paracetamol crystals from the vapor phase

NASA Astrophysics Data System (ADS)

Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.; Bordei, N. S.

2014-07-01

Phase transformations during the growth of paracetamol crystals from the vapor phase are studied by differential scanning calorimetry. It is found that the vapor-crystal phase transition is actually a superposition of two phase transitions: a first-order phase transition with variable density and a second-order phase transition with variable ordering. The latter, being a diffuse phase transition, results in the formation of a new, "pretransition," phase irreversibly spent in the course of the transition, which ends in the appearance of orthorhombic crystals. X-ray diffraction data and micrograph are presented.

Accurate expansion of cylindrical paraxial waves for its straightforward implementation in electromagnetic scattering

NASA Astrophysics Data System (ADS)

Naserpour, Mahin; Zapata-Rodríguez, Carlos J.

2018-01-01

The evaluation of vector wave fields can be accurately performed by means of diffraction integrals, differential equations and also series expansions. In this paper, a Bessel series expansion which basis relies on the exact solution of the Helmholtz equation in cylindrical coordinates is theoretically developed for the straightforward yet accurate description of low-numerical-aperture focal waves. The validity of this approach is confirmed by explicit application to Gaussian beams and apertured focused fields in the paraxial regime. Finally we discuss how our procedure can be favorably implemented in scattering problems.

Preparation and drug release behavior of temperature-responsive mesoporous carbons

NASA Astrophysics Data System (ADS)

Wang, Xiufang; Liu, Ping; Tian, Yong

2011-06-01

A temperature-responsive composite based on poly (N-isopropylacrylamide) (PNIPAAm) and ordered mesoporous carbons (OMCs) has been successfully prepared by a simple wetness impregnation technique. The structures and properties of the composite were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 sorption, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The results showed that the inclusion of PNIPAAm had not greatly changed the basic ordered pore structure of the OMCs. Ibuprofen (IBU) was selected as model drug, and in vitro test of IBU release exhibited a temperature-responsive controlled release delivery.

Study of the physical properties of a mesogenic mixture showing induced smectic A(d) phase by refractive index, density and x-ray diffraction measurements.

PubMed

Roy, P D; Prasad, A; Das, M K

2009-02-18

The binary mixture of 4-n-pentyl phenyl 4-n'-hexyloxy benzoate (ME6O.5) and p-cyanophenyl trans-4-pentyl cyclohexane carboxylate (CPPCC) shows the presence of an induced smectic A(d) phase in a certain concentration range 0.030.33, whereas there is a discontinuity in these values for mixtures with x<0.33, consistent with the density and transition entropy measurements done on this system. The orientational order parameter, measured from x-ray diffraction studies, are somewhat smaller than those obtained from refractive index measurement in the induced smectic phase for all the mixtures. In the smectic phase, the OOP values initially increases with molar concentration up to x = 0.24 and then decreases showing a broad minima around x = 0.4. The variation of layer thickness in the induced smectic phase with composition has been explained by assuming the formation of homo- and heterodimers. We conclude that the possible packing of molecules in the induced smectic A(d) phase stabilizes the layers but increases the orientational free volume, consistent with the lower orientational order parameter.

Lattice strain of osmium diboride under high pressure and nonhydrostatic stress

NASA Astrophysics Data System (ADS)

Kavner, Abby; Weinberger, Michelle B.; Shahar, Anat; Cumberland, Robert W.; Levine, Jonathan B.; Kaner, Richard B.; Tolbert, Sarah H.

2012-07-01

The lattice strain behavior of osmium diboride—a member of a group of third-row transition metal borides associated with hard/superhard behavior—has been studied using radial diffraction in a diamond anvil cell under high pressure and non-hydrostatic stress. We interpret the average values of the measured lattice strains as a lower-bound to the lattice-plane dependent yield strengths using existing estimates for the elastic constants of OsB2, with a yield strength of 11 GPa at 27.5 GPa of hydrostatic pressure. The measured differential lattice strains show significant plane-dependent anisotropy, with the (101) lattice plane showing the largest differential strain and the (001) lattice plane showing the least strain. At the highest pressure, the a-axis develops a larger compressive strain and supports a larger differential strain than either the b or c axes. This causes an increase in the c/a ratio and a decrease in the a/b ratio especially in the maximum stress direction. The large strength anisotropy of this material points to possible ways to modulate directional mechanical properties by taking advantage of the interplay between aggregate polycrystalline texture with directional mechanical properties.

Effect of Water-Glass Coating on HA and HA-TCP Samples for MSCs Adhesion, Proliferation, and Differentiation.

PubMed

Bajpai, Indu; Kim, Duk Yeon; Kyong-Jin, Jung; Song, In-Hwan; Kim, Sukyoung

2016-01-01

Ca-P and silicon based materials have become very popular as bone tissue engineering materials. In this study, water-glass (also known as sodium silicate glass) was coated on sintered hydroxyapatite (HA) and HA-TCP (TCP stands for tricalcium phosphate) samples and subsequently heat-treated at 600°C for 2 hrs. X-rays diffraction showed the presence of β- and α-TCP phases along with HA in the HA-TCP samples. Samples without coating, with water-glass coating, and heat-treated after water-glass coating were used to observe the adhesion and proliferation response of bone marrow derived-mesenchymal stem cells (MSCs). Cell culture was carried out for 4 hrs, 1 day, and 7 days. Interestingly, all samples showed similar response for cell adhesion and proliferation up to 7-day culture but fibronectin, E-cadherin, and osteogenic differentiation related genes (osteocalcin and osteopontin) were significantly induced in heat-treated water-glass coated HA-TCP samples. A water-glass coating on Ca-P samples was not found to influence the cell proliferation response significantly but activated some extracellular matrix genes and induced osteogenic differentiation in the MSCs.

Human Mesenchymal Stem Cell Behavior on Segmented Polyurethanes Prepared with Biologically Active Chain Extenders

PubMed Central

Kavanaugh, Taylor E.; Clark, Amy Y.; Chan-Chan, Lerma H.; Ramírez-Saldaña, Maricela; Vargas-Coronado, Rossana F.; Cervantes-Uc, José M.; Hernández-Sánchez, Fernando; García, Andrés J.; Cauich-Rodríguez, Juan V.

2016-01-01

The development of elastomeric, bioresorbable and biocompatible segmented polyurethanes (SPUs) for use in tissue-engineering applications has attracted considerable interest because of the existing need of mechanically tunable scaffolds for regeneration of different tissues, but the incorporation of osteoinductive molecules into SPUs has been limited. In this study, segmented polyurethanes were synthesized from poly (ε-caprolactone)diol, 4,4’-methylene bis(cyclohexyl isocyanate) (HMDI) using biologically active compounds such as ascorbic acid, L-glutamine, β-glycerol phosphate, and dexamethasone as chain extenders. Fourier Transform Infrared Spectroscopy (FTIR) revealed the formation of both urethanes and urea linkages while Differential Scanning Calorimetry, Dynamic Mechanical Analysis, X-ray Diffraction and mechanical testing showed that these polyurethanes were semi-crystalline polymers exhibiting high deformations. Cytocompatibility studies showed that only SPUs containing β-glycerol phosphate supported human mesenchymal stem cell (hMSC) adhesion, growth, and osteogenic differentiation, rendering them potentially suitable for bone tissue regeneration, whereas other SPUs failed to support either cell growth or osteogenic differentiation, or both. This study demonstrates that modification of SPUs with osteogenic compounds can lead to new cytocompatible polymers for regenerative medicine applications. PMID:26704555

Kinematical calculations of RHEED intensity oscillations during the growth of thin epitaxial films

NASA Astrophysics Data System (ADS)

Daniluk, Andrzej

2005-08-01

A practical computing algorithm working in real time has been developed for calculating the reflection high-energy electron diffraction (RHEED) from the molecular beam epitaxy (MBE) growing surface. The calculations are based on the use of kinematical diffraction theory. Simple mathematical models are used for the growth simulation in order to investigate the fundamental behaviors of reflectivity change during the growth of thin epitaxial films prepared using MBE. Program summaryTitle of program:GROWTH Catalogue identifier:ADVL Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVL Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Distribution format: tar.gz Computer for which the program is designed and others on which is has been tested:Pentium-based PC Operating systems or monitors under which the program has been tested:Windows 9x, XP, NT Programming language used:Object Pascal Memory required to execute with typical data:more than 1 MB Number of bits in a word: 64 bits Number of processors used: 1 Number of lines in distributed program, including test data, etc.: 10 989 Number of bytes in distributed program, including test data, etc.:103 048 Nature of the physical problem:Reflection high-energy electron diffraction (RHEED) is a very useful technique for studying growth and surface analysis of thin epitaxial structures prepared using the molecular beam epitaxy (MBE). The simplest approach to calculating the RHEED intensity during the growth of thin epitaxial films is the kinematical diffraction theory (often called kinematical approximation), in which only a single scattering event is taken into account. The biggest advantage of this approach is that we can calculate RHEED intensity in real time. Also, the approach facilitates intuitive understanding of the growth mechanism and surface morphology [P.I. Cohen, G.S. Petrich, P.R. Pukite, G.J. Whaley, A.S. Arrott, Surf. Sci. 216 (1989) 222]. Method of solution:Epitaxial growth of thin films is modeled by a set of non-linear differential equations [P.I. Cohen, G.S. Petrich, P.R. Pukite, G.J. Whaley, A.S. Arrott, Surf. Sci. 216 (1989) 222]. The Runge-Kutta method with adaptive stepsize control was used for solving initial value problem for non-linear differential equations [W.H. Press, B.P. Flannery, S.A. Teukolsky, W.T. Vetterling, Numerical Recipes in Pascal: The Art of Scientific Computing; first ed., Cambridge University Press, 1989; See also: Numerical Recipes in C++, second ed., Cambridge University Press, 1992]. Typical running time: The typical running time is machine and user-parameters dependent. Unusual features of the program: The program is distributed in the form of a main project Growth.dpr file and an independent Rhd.pas file and should be compiled using Object Pascal compilers, including Borland Delphi.

New Composites LnBDC@AC and CB[6]@AC: From Design toward Selective Adsorption of Methylene Blue or Methyl Orange

PubMed Central

Santos, Guilherme de C.; Barros, Amanda L.; de Oliveira, Carlos A. F.; da Luz, Leonis L.; da Silva, Fausthon F.; Demets, Grégoire J.-F.; Alves Júnior, Severino

2017-01-01

New porous composites LnBDC@AC (AC = Activated carbon, Ln = Eu and Gd and BDC = 1,4-benzenedicaboxylate) and CB[6]@AC (CB[6] = Cucurbit[6]uril) were obtained using hydrothermal route. The LnBDC and CB[B] are located inside the pore of the carbon materials as was observed in SEM-EDS, XRPD and FT-IR analysis. Porosimetry analysis showed values typically between AC and LnBDC material, with pore size and surface area, respectively, 29,56 Å and 353.98 m2g-1 for LnBDC@AC and 35,53 Å and 353.98 m2g-1 for CB[6]@AC. Both materials showed good absorptive capacity of metil orange (MO) and methylene blue (MB) with selectivity as a function of pH. For acid pH, both materials present selectivity by MB and alkaline pH for MO, with notable performance for CB[6]@AC. Additionally, europium luminescence was used as structural probe to investigate the coordination environment of Eu3+ ions in the EuBDC@AC composite after adsorption experiment. PMID:28107440

Physicochemical regeneration of high silica zeolite Y used to clean-up water polluted with sulfonamide antibiotics.

PubMed

Braschi, I; Blasioli, S; Buscaroli, E; Montecchio, D; Martucci, A

2016-05-01

High silica zeolite Y has been positively evaluated to clean-up water polluted with sulfonamides, an antibiotic family which is known to be involved in the antibiotic resistance evolution. To define possible strategies for the exhausted zeolite regeneration, the efficacy of some chemico-physical treatments on the zeolite loaded with four different sulfonamides was evaluated. The evolution of photolysis, Fenton-like reaction, thermal treatments, and solvent extractions and the occurrence in the zeolite pores of organic residues eventually entrapped was elucidated by a combined thermogravimetric (TGA-DTA), diffractometric (XRPD), and spectroscopic (FT-IR) approach. The chemical processes were not able to remove the organic guest from zeolite pores and a limited transformation on embedded molecules was observed. On the contrary, both thermal treatment and solvent extraction succeeded in the regeneration of the zeolite loaded from deionized and natural fresh water. The recyclability of regenerated zeolite was evaluated over several adsorption/regeneration cycles, due to the treatment efficacy and its stability as well as the ability to regain the structural features of the unloaded material. Copyright © 2015. Published by Elsevier B.V.

Development of megestrol acetate solid dispersion nanoparticles for enhanced oral delivery by using a supercritical antisolvent process.

PubMed

Ha, Eun-Sol; Kim, Jeong-Soo; Baek, In-Hwan; Yoo, Jin-Wook; Jung, Yunjin; Moon, Hyung Ryong; Kim, Min-Soo

2015-01-01

In the present study, solid dispersion nanoparticles with a hydrophilic polymer and surfactant were developed using the supercritical antisolvent (SAS) process to improve the dissolution and oral absorption of megestrol acetate. The physicochemical properties of the megestrol acetate solid dispersion nanoparticles were characterized using scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and a particle-size analyzer. The dissolution and oral bioavailability of the nanoparticles were also evaluated in rats. The mean particle size of all solid dispersion nanoparticles that were prepared was <500 nm. Powder X-ray diffraction and differential scanning calorimetry measurements showed that megestrol acetate was present in an amorphous or molecular dispersion state within the solid dispersion nanoparticles. Hydroxypropylmethyl cellulose (HPMC) solid dispersion nanoparticles significantly increased the maximum dissolution when compared with polyvinylpyrrolidone K30 solid dispersion nanoparticles. The extent and rate of dissolution of megestrol acetate increased after the addition of a surfactant into the HPMC solid dispersion nanoparticles. The most effective surfactant was Ryoto sugar ester L1695, followed by D-α-tocopheryl polyethylene glycol 1000 succinate. In this study, the solid dispersion nanoparticles with a drug:HPMC:Ryoto sugar ester L1695 ratio of 1:2:1 showed >95% rapid dissolution within 30 minutes, in addition to good oral bioavailability, with approximately 4.0- and 5.5-fold higher area under the curve (0-24 hours) and maximum concentration, respectively, than raw megestrol acetate powder. These results suggest that the preparation of megestrol acetate solid dispersion nanoparticles using the supercritical antisolvent process is a promising approach to improve the dissolution and absorption properties of megestrol acetate.

Temperature-dependent IR spectroscopic and structural study of 18-crown-6 chelating ligand in the complexation with sodium surfactant salts and potassium picrate.

PubMed

Mihelj, Tea; Tomašić, Vlasta; Biliškov, Nikola; Liu, Feng

2014-04-24

18-crown-6 ether (18C6) complexes with the following anionic surfactants: sodium n-dodecylsulfate (18C6-NaDS), sodium 4-(1-pentylheptyl)benzenesulfonate (18C6-NaDBS); and potassium picrate (18C6-KP) were synthesized and studied in terms of their thermal and structural properties. Physico-chemical properties of new solid 1:1 coordination complexes were characterized by infrared (IR) spectroscopy, thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray diffraction and microscopic observations. The strength of coordination between Na(+) and oxygen atoms of 18C6 ligand does not depend on anionic part of the surfactant, as established by thermodynamical parameters obtained by temperature-dependent IR spectroscopy. Each of these complexes exhibit different kinds of endothermic transitions in heating scan. Diffraction maxima obtained by SAXS and WAXS, refer the behavior of the compounds 18C6-NaDS and 18C6-NaDBS as smectic liquid crystalline. Distortion of 18C6-NaDS and 18C6-KP complexes occurs in two steps. Temperature of the decomplexation of solid crystal complex 18C6-KP is considerably higher than of mesophase complexes, 18C6-NaDS, and 18C6-NaDBS. The structural and liquid crystalline properties of novel 18-crown-ether complexes are function of anionic molecule geometry, type of chosen cation (Na(+), K(+)), as well as architecture of self-organized aggregates. A good combination of crown ether unit and amphiphile may provide a possibility for preparing new functionalized materials, opening the research field of ion complexation and of host-guest type behavior. Copyright © 2013 Elsevier B.V. All rights reserved.

High Pressure Strength Study on NaCl

NASA Astrophysics Data System (ADS)

Mi, Z.; Shieh, S. R.; High Pressure Mineral Physics Group

2010-12-01

Yield strength is regarded as one important property related to rheological characteristics of minerals in the Earth’s interior. The strength study of NaCl, a popular pressure medium in static high pressure experiments, has been carried out under non-hydrostatic conditions in a diamond anvil cell up to 43 GPa at room temperature using radial energy dispersive X-ray diffraction technique. Phase transformation from B1 (rock salt structure) to B2 (CsCl structure) starts at 29.4 GPa, and is complete at 32.1 GPa. Bulk modulus obtained by third order Birch-Manurgham equation of state is 25.5 GPa with pressure derivative 4.6 for B1 phase, and 30.78 GPa with pressure derivative 4.32 GPa for B2 phase, which are in a good agreement with previous studies. The differential stress of NaCl B1 phase shows very gentle increase with pressure, which indicates that NaCl is a very good pressure-transmitting medium at pressure below 30 GPa. However, the differential stress increases more abruptly for B2 phase and this may imply that NaCl can no longer be regarded as a “soft” pressure medium at very high pressures. For B1 phase, (111) is the strongest plane and (200) is the weakest plane, while (200) becomes the strongest plane in B2 phase. Pure NaCl is weaker than mixture MgO and NaCl, which indicates that soft material become stronger when mixed with hard material. The yield strength of B2 obtained through energy dispersive X-ray diffraction technique increase linearly, while the value derived by pressure gradient method shows jagged trend.

Manilkara zapota (Linn.) Seeds: A Potential Source of Natural Gum

PubMed Central

Singh, Sudarshan; Bothara, Sunil B.

2014-01-01

Mucilage isolated from seeds of Manilkara zapota (Linn.) P. Royen syn. is a plant growing naturally in the forests of India. This mucilage is yet to be commercially exploited, and characterized as polymer. Various physicochemical methods like particle size analysis, scanning electron microscopy, thermal analysis, gel permeation chromatography, X-ray diffraction spectrometry, zeta potential, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy have been employed to characterize this gum in the present study. Particle size analyses suggest that mucilage has particle size in nanometer. Scanning electron microscopy analysis suggests that the mucilage has irregular particle size. The glass transition temperature of the gum was observed to be 138°C and 136°C by differential scanning calorimetry and differential thermal analysis, respectively. The thermogravimetric analysis suggested that mucilage had good thermal stability. The average molecular weight of mucilage was determined to be 379180, by gel permeation chromatography, while the viscosity of mucilage was observed to be 219.1 cP. The X-ray diffraction spectrometry pattern of the mucilage indicates a completely amorphous structure. Elemental analysis of the gum revealed the contents of carbon, hydrogen, nitrogen, and sulfur to be 80.9 (%), 10.1 (%), 1.58 (%), and 512 (mg/kg), respectively. Mucilage had specific content of calcium, magnesium, potassium, lower concentrations of aluminum, cadmium, cobalt, lead, and nickel. The major functional groups identified from FT-IR spectrum include 3441 cm−1 (–OH), 1660 cm−1 (Alkenyl C–H & C=C Stretch), 1632 cm−1 (–COO–), 1414 cm−1 (–COO–), and 1219 cm−1 (–CH3CO). Analysis of mucilage by paper chromatography and 1D NMR, indicated the presence of rhamnose, xylose, arabinose, mannose, and fructose. PMID:24729907

Effect of SiO2/B2O3 Ratio on the Crystallization Behavior and Dielectric Properties of Barium Strontium Titanate Glass-Ceramics Prepared by Sol-Gel Process

NASA Astrophysics Data System (ADS)

Chen, Yongzhou; Zhang, Yong; Song, Xiaozhen; Shen, Ziqin; Zhang, Tianyuan

2018-05-01

Ferroelectric glass-ceramics, with a basic composition 90 wt.% (Ba0.65Sr0.35)TiO3-10 wt.% (B2O3-nSiO2) (n = 0.5, 1, 3, 5) were synthesized by the sol-gel method and their phase development and dielectric properties were investigated by differential thermal analysis, x-ray diffraction, field emission scanning electron microscopy, dielectric temperature curves and impedance spectroscopy. From the differential thermal analysis, glass transition and crystallization behavior can be observed. From the x-ray diffraction study, two crystalline phases (Ba,Sr)TiO3 and Ba2TiSi2O8 were formed over the entire composition range of the glass-ceramics. In addition, the main crystal phase has undergone a transformation from (Ba,Sr)TiO3 to Ba2TiSi2O8 with the increase of n. A typical structure in which the crystal phase was surrounded by a glassy matrix has been observed in the scanning electron microscope images. As a result of temperature dependent dielectric property measurements, the dielectric constant increased obviously with the increase of n from 0.5 to 1. Further increasing n led to a reduction of the dielectric constant, which is in coincidence with the variation of the intensity of (Ba,Sr)TiO3 phase with n. According to the impedance spectroscopy analysis and the activation energy calculation, the relaxation peak in both Z″ and M″ data should be attributed to the crystal-glass interface, and the change of conduction mechanism with the increase of SiO2/B2O3 ratio may be attributed to the corresponding transition of the main crystal phase.

Preparation and characterization of biomimetic silk fibroin/chitosan composite nanofibers by electrospinning for osteoblasts culture.

PubMed

Chen, Jyh-Ping; Chen, Shih-Hsien; Lai, Guo-Jyun

2012-03-06

In this study, we have successfully fabricated electrospun bead-free silk fibroin [SF]/chitosan [CS] composite nanofibers [NFs] covering the whole range of CS content (0%, 25%, 50%, 75%, and 100%). SF/CS spinning solutions were prepared in a mixed solvent system of trifluoroacetic acid [TFA] and dichloromethane. The morphology of the NFs was observed by scanning electron microscope, and the average fiber diameter ranges from 215 to 478 nm. Confocal laser scanning microscopy confirms the uniform distribution of SF and CS within the composite NFs. To increase biocompatibility and preserve nanostructure when seeded with cells in culture medium, NFs were treated with an ethanol/ammonia aqueous solution to remove residual TFA and to change SF protein conformation. After the chemical treatment, SF/CS NFs could maintain the original structure for up to 54 days in culture medium. Properties of pristine and chemically treated SF/CS NFs were investigated by Fourier transform infrared spectroscopy [FT-IR], X-ray diffraction [XRD], and thermogravimetry/differential scanning calorimetry [TG/DSC]. Shift of absorption peaks in FT-IR spectra confirms the conformation change of SF from random coil to β-sheet by the action of ethanol, which is also consistent with the SF crystalline diffraction patterns measured by XRD. From TG/DSC analysis, the decomposition temperature peaks due to salt formation from TFA and protonated amines disappeared after chemical treatment, indicating complete removal of TFA by binding with ammonium ions during the treatment. This was also confirmed with the disappearance of F1s peak in X-ray photoelectron spectroscopy spectra and disappearance of TFA salt peaks in FT-IR spectra. The composite NFs could support the growth and osteogenic differentiation of human fetal osteoblastic [hFOB] cells, but each component in the composite NF shows distinct effect on cell behavior. SF promotes hFOB proliferation while CS enhances hFOB differentiation. The composite SF/CS NFs will be suitable for bone tissue engineering applications by choosing a suitable blend composition.PACS: 87.85.jf; 87.85.Rs; 68.37.Hk.

Purification, crystallization and preliminary X-ray diffraction of human S100A15

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

Boeshans, Karen M.; Wolf, Ronald; Voscopoulos, Christopher

2006-05-01

S100 proteins are differentially expressed during epithelial cell maturation, tumorigenesis and inflammation. The novel human S100A15 protein has been cloned, expressed, purified and crystallized in two crystal forms, a triclinic and a monoclinic form, which diffract to 1.7 and 2.0 Å, respectively. Human S100A15 is a novel member of the S100 family of EF-hand calcium-binding proteins and was recently identified in psoriasis, where it is significantly upregulated in lesional skin. The protein is implicated as an effector in calcium-mediated signal transduction pathways. Although its biological function is unclear, the association of the 11.2 kDa S100A15 with psoriasis suggests that itmore » contributes to the pathogenesis of the disease and could provide a molecular target for therapy. To provide insight into the function of S100A15, the protein was crystallized to visualize its structure and to further the understanding of how the many similar calcium-binding mediator proteins in the cell distinguish their cognate target molecules. The S100A15 protein has been cloned, expressed and purified to homogeneity and produced two crystal forms. Crystals of form I are triclinic, with unit-cell parameters a = 33.5, b = 44.3, c = 44.8 Å, α = 71.2, β = 68.1, γ = 67.8° and an estimated two molecules in the asymmetric unit, and diffract to 1.7 Å resolution. Crystals of form II are monoclinic, with unit-cell parameters a = 82.1, b = 33.6, c = 52.2 Å, β = 128.2° and an estimated one molecule in the asymmetric unit, and diffract to 2.0 Å resolution. This structural analysis of the human S100A15 will further aid in the phylogenic comparison between the other members of the S100 protein family, especially the highly homologous paralog S100A7.« less

Structural variability in Cu(I) and Ag(I) coordination polymers with a flexible dithione ligand: Synthesis, crystal structure, microbiological and theoretical studies

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

Beheshti, Azizolla, E-mail: a.beheshti@scu.ac.ir; Nozarian, Kimia; Babadi, Susan Soleymani

Two new compounds namely [Cu(SCN)(µ-L)]{sub n} (1) and ([Ag (µ{sub 2}-L)](ClO{sub 4})){sub n} (2) have been synthesized at room temperature by one-pot reactions between the 1,1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole- 2-thione) (L) and appropriate copper(I) and silver(I) salts. These polymers have been characterized by single crystal X-ray diffraction, XRPD, TGA, elemental analysis, infrared spectroscopy, antibacterial activity and scanning probe microscopy studies. In the crystal structure of 1, copper atoms have a distorted trigonal planar geometry with a CuS{sub 2}N coordination environment. Each of the ligands in the structure of 1 acting as a bidentate S-bridging ligand to form a 1D chain structure. Additionally, themore » adjacent 1D chains are interconnected by the intermolecular C-H…S interactions to create a 2D network structure. In contrast to 1, in the cationic 3D structure of 2 each of the silver atoms exhibits an AgS{sub 4} tetrahedral geometry with 4-membered Ag{sub 2}S{sub 2} rings. In the structure of 2, the flexible ligand adopts two different conformations; gauche-anti-gauche and anti-anti-anti. The antibacterial studies of these polymers showed that polymer 2 is more potent antibacterial agent than 1. Scanning probe microscopy (SPM) study of the treated bacteria was carried out to investigate the structural changes cause by the interactions between the polymers and target bacteria. Theoretical study of polymer 1 investigated by the DFT calculations indicates that observed transitions at 266 nm and 302 nm in the UV–vis spectrum could be attributed to the π→π* and MLCT transitions, respectively. - Graphical abstract: Two new Cu(I) and Ag(I) coordination polymers have been have been synthesized by one-pot reactions. Copper complex has a 2D non-covalent structure, but silver compound is a 3D coordination compound. These compounds have effective antibacterial activity. - Highlights: • Cu(I) and Ag(I) based coordination polymers have different network structures. • Ag(I) polymer has more antibacterial activity than Cu(I) polymer. • DFT calculations of Cu(I) polymer has been investigated. • Cu(I) and Ag(I) polymers can destroy the structure of chromosomal and plasmid DNA.« less

Energy and Mass-Number Dependence of Hadron-Nucleus Total Reaction Cross Sections

NASA Astrophysics Data System (ADS)

Kohama, Akihisa; Iida, Kei; Oyamatsu, Kazuhiro

2016-09-01

We thoroughly investigate how proton-nucleus total reaction cross sections depend on the target mass number A and the proton incident energy. In doing so, we systematically analyze nuclear reaction data that are sensitive to nuclear size, namely, proton-nucleus total reaction cross sections and differential elastic cross sections, using a phenomenological black-sphere approximation of nuclei that we are developing. In this framework, the radius of the black sphere is found to be a useful length scale that simultaneously accounts for the observed proton-nucleus total reaction cross section and first diffraction peak in the proton elastic differential cross section. This framework, which is shown here to be applicable to antiprotons, is expected to be applicable to any kind of projectile that is strongly attenuated in the nucleus. On the basis of a cross-section formula constructed within this framework, we find that a less familiar A1/6 dependence plays a crucial role in describing the energy dependence of proton-nucleus total reaction cross sections.

Hydroxyapatite thin films grown by pulsed laser deposition and matrix assisted pulsed laser evaporation: Comparative study

NASA Astrophysics Data System (ADS)

Popescu-Pelin, G.; Sima, F.; Sima, L. E.; Mihailescu, C. N.; Luculescu, C.; Iordache, I.; Socol, M.; Socol, G.; Mihailescu, I. N.

2017-10-01

Pulsed Laser Deposition (PLD) and Matrix Assisted Pulsed Laser Evaporation (MAPLE) techniques were applied for growing hydroxyapatite (HA) thin films on titanium substrates. All experiments were conducted in a reaction chamber using a KrF* excimer laser source (λ = 248 nm, τFWHM ≈ 25 ns). Half of the samples were post-deposition thermally treated at 500 °C in a flux of water vapours in order to restore crystallinity and improve adherence. Coating surface morphologies and topographies specific to the deposition method were evidenced by scanning electron, atomic force microscopy investigations and profilometry. They were shown to depend on deposition technique and also on the post-deposition treatment. Crystalline structure of the coatings evaluated by X-ray diffraction was improved after thermal treatment. Biocompatibility of coatings, cellular adhesion, proliferation and differentiation tests were conducted using human mesenchymal stem cells (MSCs). Results showed that annealed MAPLE deposited HA coatings were supporting MSCs proliferation, while annealed PLD obtained films were stimulating osteogenic differentiation.

Effect of testosterone incorporation on cell proliferation and differentiation for polymer-bioceramic composites.

PubMed

da Costa, Kelen Jorge Rodrigues; Passos, Joel J; Gomes, Alinne D M; Sinisterra, Rubén D; Lanza, Célia R M; Cortés, Maria Esperanza

2012-11-01

In the current study, we characterized the polycaprolactone (PCL), poly(lactic acid-co-glycolic acid) (PLGA), and biphasic calcium phosphate (BCP) composites coated with testosterone propionate (T) using Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD). Osteoblastic cells were seeded with PCL/BCP, PCL/BCP/T, PLGA/PCL/BCP and PLGA/PCL/BCP/T scaffolds, and cell viability, proliferation, differentiation and adhesion were analyzed. The results of physic-chemical experiments showed no displacements or suppression of bands in the FTIR spectra of scaffolds. The XRD patterns of the scaffolds showed an amorphous profile. The osteoblastic cells viability and proliferation increased in the presence of composites with testosterone over 72 h, and were significantly greater when PLGA/PCL/BCP/T scaffold was tested against PCL/BCP/T. Furthermore alkaline phosphatase production was significantly greater in the same group. In conclusion, the PLGA/PCL/BCP scaffold with testosterone could be a promising option for bone tissue applications due to its biocompatibility and its stimulatory effect on cell proliferation.

Mono-Mercury Doping of Au25 and the HOMO/LUMO Energies Evaluation Employing Differential Pulse Voltammetry.

PubMed

Liao, Lingwen; Zhou, Shiming; Dai, Yafei; Liu, Liren; Yao, Chuanhao; Fu, Cenfeng; Yang, Jinlong; Wu, Zhikun

2015-08-05

Controlling the bimetal nanoparticle with atomic monodispersity is still challenging. Herein, a monodisperse bimetal nanoparticle is synthesized in 25% yield (on gold atom basis) by an unusual replacement method. The formula of the nanoparticle is determined to be Au24Hg1(PET)18 (PET: phenylethanethiolate) by high-resolution ESI-MS spectrometry in conjunction with multiple analyses including X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). X-ray single-crystal diffraction reveals that the structure of Au24Hg1(PET)18 remains the structural framework of Au25(PET)18 with one of the outer-shell gold atoms replaced by one Hg atom, which is further supported by theoretical calculations and experimental results as well. Importantly, differential pulse voltammetry (DPV) is first employed to estimate the highest occupied molecular orbit (HOMO) and the lowest unoccupied molecular orbit (LUMO) energies of Au24Hg1(PET)18 based on previous calculations.

A high-throughput differential filtration assay to screen and select detergents for membrane proteins

PubMed Central

Vergis, James M.; Purdy, Michael D.; Wiener, Michael C.

2015-01-01

Structural studies on integral membrane proteins are routinely performed on protein–detergent complexes (PDCs) consisting of purified protein solubilized in a particular detergent. Of all the membrane protein crystal structures solved to date, a subset of only four detergents has been used in more than half of these structures. Unfortunately, many membrane proteins are not well behaved in these four detergents and/or fail to yield well-diffracting crystals. Identification of detergents that maintain the solubility and stability of a membrane protein is a critical step and can be a lengthy and “protein-expensive” process. We have developed an assay that characterizes the stability and size of membrane proteins exchanged into a panel of 94 commercially available and chemically diverse detergents. This differential filtration assay (DFA), using a set of filtered microplates, requires sub-milligram quantities of purified protein and small quantities of detergents and other reagents and is performed in its entirety in several hours. PMID:20667442

Role of intensive milling in the processing of barium ferrite/magnetite/iron hybrid magnetic nano-composites via partial reduction of barium ferrite

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

Molaei, M.J., E-mail: mj.molaee@merc.ac.ir; Delft Chem Tech, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft; Ataie, A.

2015-03-15

In this research a mixture of barium ferrite and graphite was milled for different periods of time and then heat treated at different temperatures. The effects of milling time and heat treatment temperature on the phase composition, thermal behavior, morphology and magnetic properties of the samples have been investigated using X-ray diffraction, differential thermal analysis, high resolution transmission electron microscopy and vibrating sample magnetometer techniques, respectively. X-ray diffraction results revealed that BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} nanocomposites form after a 20 h milling due to the partial reduction of BaFe{sub 12}O{sub 19}. High resolution transmission electron microscope images of amore » 40 h milled sample showed agglomerated structure consisting of nanoparticles with a mean particle size of 30 nm. Thermal analysis of the samples via differential thermal analysis indicated that for un-milled samples, heat treatment up to 900 °C did not result in α-Fe formation, while for a 20 h milled sample heat treatment at 700 °C resulted in reduction process progress to the formation of α-Fe. Wustite was disappeared in an X-ray diffraction pattern of a heat treated sample at 850 °C, by increasing the milling time from 20 to 40 h. By increasing the milling time, the structure of heat treated samples becomes magnetically softer due to an increase in saturation magnetization and a decrease in coercivity. Saturation magnetization and coercivity of a sample milled for 20 h and heat treated at 850 °C were 126.3 emu/g and 149.5 Oe which by increasing the milling time to 40 h, alter to 169.1 emu/g and 24.3 Oe, respectively. High coercivity values of milled and heat treated samples were attributed to the nano-scale formed iron particles. - Graphical abstract: Display Omitted - Highlights: • Barium ferrite and graphite were treated mechano-thermally. • Increasing milling time increases reduction progress after heat treatment. • Composites including iron nano-crystals forms by milling and heat treatment. • Shorter milling time results in higher H{sub C} of the milled and heat treated samples.« less

Dual functions of silver nanoparticles in F9 teratocarcinoma stem cells, a suitable model for evaluating cytotoxicity- and differentiation-mediated cancer therapy

PubMed Central

Han, Jae Woong; Gurunathan, Sangiliyandi; Choi, Yun-Jung; Kim, Jin-Hoi

2017-01-01

Background Silver nanoparticles (AgNPs) exhibit strong antibacterial and anticancer activity owing to their large surface-to-volume ratios and crystallographic surface structure. Owing to their various applications, understanding the mechanisms of action, biological interactions, potential toxicity, and beneficial effects of AgNPs is important. Here, we investigated the toxicity and differentiation-inducing effects of AgNPs in teratocarcinoma stem cells. Materials and methods AgNPs were synthesized and characterized using various analytical techniques such as UV–visible spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The cellular responses of AgNPs were analyzed by a series of cellular and biochemical assays. Gene and protein expressions were analyzed by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. Results The AgNPs showed typical crystalline structures and spherical shapes (average size =20 nm). High concentration of AgNPs induced cytotoxicity in a dose-dependent manner by increasing lactate dehydrogenase leakage and reactive oxygen species. Furthermore, AgNPs caused mitochondrial dysfunction, DNA fragmentation, increased expression of apoptotic genes, and decreased expression of antiapoptotic genes. Lower concentrations of AgNPs induced neuronal differentiation by increasing the expression of differentiation markers and decreasing the expression of stem cell markers. Cisplatin reduced the viability of F9 cells that underwent AgNPs-induced differentiation. Conclusion The results showed that AgNPs caused differentially regulated cytotoxicity and induced neuronal differentiation of F9 cells in a concentration-dependent manner. Therefore, AgNPs can be used for differentiation therapy, along with chemotherapeutic agents, for improving cancer treatment by targeting specific chemotherapy-resistant cells within a tumor. Furthermore, understanding the molecular mechanisms of apoptosis and differentiation in stem cells could also help in developing new strategies for cancer stem cell (CSC) therapies. The findings of this study could significantly contribute to the nanomedicine because this study is the first of its kind, and our results will lead to new strategies for cancer and CSC therapies. PMID:29066898

Synthesis, crystal growth, structural, thermal and optical properties of naphthalene picrate an organic NLO material.

PubMed

Chandramohan, A; Bharathikannan, R; Kandavelu, V; Chandrasekaran, J; Kandhaswamy, M A

2008-12-01

Crystalline substance of naphthalene picrate (NP) was synthesized and single crystals were grown using slow evaporation solution growth technique. The solubility of the naphthalene picrate complex was estimated using different solvents such as chloroform and benzene. The material was characterized by elemental analysis, powder X-ray diffraction (XRD), nuclear magnetic resonance (NMR) and fourier transform-infrared (FT-IR) techniques. The electronic absorption was studied through UV-vis spectrophotometer. Thermal behavior and stability of the crystal were studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The second harmonic generation (SHG) of the material was confirmed using Nd:YAG laser.