Stability of freeze-dried products subjected to microcomputed tomography radiation doses

2021 ◽  
Vol 73 (2) ◽  
pp. 212-220
Author(s):  
Tim Wenzel ◽  
Achim Sack ◽  
Patrick Müller ◽  
Thorsten Poeschel ◽  
Sonja Schuldt-Lieb ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Structural Information ◽  
Microcomputed Tomography ◽  
Radiation Doses ◽  
Stability Testing ◽  
X Ray ◽  
Accelerated Stability ◽  
Freeze Dried ◽  
The Stability ◽  
Non Destructive

Abstract Objectives Microcomputed tomography (µCT) is a powerful analytical tool for non-invasive structural analysis. The stability of drug substances and formulations subjected to X-ray radiation may be a concern in the industry. This study examines the effect of X-ray radiation on the stability of freeze-dried pharmaceuticals. The investigation is a proof of concept study for the safety of µCT X-ray radiation doses during the non-destructive investigation of freeze-dried products. Methods Different formulations of clotrimazole, insulin and l-lactate dehydrogenase were freeze-dried and the products exposed to a defined dose of radiation by µCT. Conservative freeze-drying conditions were used. Irradiated and normal samples were analysed for their stability directly after freeze-drying and after stability testing. Key findings The stability of model compounds was well maintained during freeze-drying. Some degradation of all compounds occurred during accelerated stability testing. The results showed no differences between the irradiated and normal state directly after freeze-drying and accelerated stability testing. Conclusions No evidence of a detrimental effect of 100 Gy X-ray exposure on a model small molecule, peptide and protein compound was found while useful structural information could be obtained. Consequently, the technology may be useful as a non-destructive tool for product inspections if the formulation proves stable.

Revealing gross three-dimensional structure in the SEM

1987 ◽  
Vol 45 ◽  
pp. 656-657
Author(s):  
Sterling P. Newberry
Keyword(s):  
Freeze Drying ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Small Object ◽  
Final Solution ◽  
Dimensional Representation ◽  
X Ray ◽  
Three Dimensional Representation ◽  
Freeze Dried ◽  
Critical Point Drying

The beautiful three dimensional representation of small object surfaces by the SEM leads one to search for ways to open up the sample and look inside. Could this be the answer to a better microscopy for gross biological 3-D structure? We know from X-Ray microscope images that Freeze Drying and Critical Point Drying give promise of adequately preserving gross structure. Can we slice such preparations open for SEM inspection? In general these preparations crush more readily than they slice. Russell and Dagihlian got around the problem by “deembedding” a section before imaging. This some what defeats the advantages of direct dry preparation, thus we are reluctant to accept it as the final solution to our problem. Alternatively, consider fig 1 wherein a freeze dried onion root has a window cut in its surface by a micromanipulator during observation in the SEM.

X-RAY TOMOGRAPHY STUDIES OF PREHISTORIC CERAMIC ARTIFACTS

2014 ◽  
Vol 27 ◽  
pp. 1460135
Author(s):  
CARMEN PAVEL ◽  
FLORIN CONSTANTIN ◽  
COSMIN IOAN SUCIU ◽  
ROXANA BUGOI
Keyword(s):  
Computed Tomography ◽  
Cultural Heritage ◽  
Nuclear Physics ◽  
Structural Information ◽  
Ct Scans ◽  
Visual Examination ◽  
X Ray ◽  
X Ray Computed ◽  
Internal Configuration ◽  
Non Destructive

X-ray Computed Tomography (CT) is a powerful non-destructive technique that can yield interesting structural information not discernible through visual examination only. This paper presents the results of the CT scans of four objects belonging to the Romanian cultural heritage attributed to the Vinča, Cucuteni and Cruceni-Belegiš cultures. The study was performed with an X-ray tomographic device developed at the Department for Applied Nuclear Physics from Horia Hulubei National Institute for Nuclear Physics and Engineering in Măgurele, Romania. This apparatus was specially designed for archaeometric studies of low-Z artifacts: ceramic, wood, bone. The tomographic investigations revealed the internal configuration of the objects and provided information about the degree to which the previous manipulations affected the archaeological items. Based on the X-ray images resulting from the CT scans, hints about the techniques used in the manufacturing of the artifacts were obtained, as well as some indications useful for conservation/restoration purposes.

scholarly journals Study of Iron Gall Inks, Ingredients and Paper Composition Using Non-Destructive Techniques

Heritage ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 2691-2703 ◽  
Author(s):  
Victoria Corregidor ◽  
Rita Viegas ◽  
Luís M. Ferreira ◽  
Luís C. Alves
Keyword(s):  
Structural Information ◽  
Uv Light ◽  
Raw Materials ◽  
Structural Characteristics ◽  
Crystallinity Index ◽  
X Ray ◽  
Paper Degradation ◽  
Iron Gall ◽  
Non Destructive ◽  
Non Destructive Techniques

Old manuscripts are among the most important elements of the cultural and historical heritage of ancient knowledge. Unfortunately, many of them suffer from degradation, mostly those written with iron gall inks. In the present work, a study using non-destructive techniques was designed with the aim of analyzing the elemental composition and structural characteristics of iron gall inks, reproduced in laboratory, paper and their interaction when the ink is deposited on paper, inducing the paper degradation. Proton induced X-ray emission, X-ray diffraction and Fourier-transform infrared spectroscopy provided the elemental and structural information, and photography under infrared (IR) and ultraviolet (UV) light allowed the differentiation between manufactured inks. Results show that the first step of inked paper deterioration is due to acid-hydrolysis of the cellulose and the presence of reactive Fe(II) species by reducing the crystallinity index of the paper, which is affected depending on the ink recipe and the starting raw materials. These results will be useful to future studies on ancient documents written with iron gall inks, which suffer deterioration due to ink corrosion, and to differentiate between the different paper degradation mechanisms.

Synthesis of Porous Ceramics Through Directional Solidification and Freeze-Drying

2003 ◽  
Vol 788 ◽  
Author(s):  
Predrag Kisa ◽  
Patrick Fisher ◽  
Al Olszewski ◽  
Ian Nettleship ◽  
Nicholas G. Eror
Keyword(s):  
Freeze Drying ◽  
Three Dimensional ◽  
Porous Ceramics ◽  
Porous Structures ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Freeze Dried ◽  
Silica Sols

ABSTRACTThis study investigated the microstructural characteristics of directionally solidified freeze-dried silica sols. Porous structures were formed by depositing silica sol on silicon (100) single crystals. The deposited sols were unidirectionaly solidified by placing the silicon substrate on a copper block immersed in liquid nitrogen and then subsequently freeze-dried. Freeze drying removal of ice crystals created three-dimensional pore channels ranging from 3 to10 micrometers in diameter aggregated in grain like colonies 50–100 micrometers in diameter. Pore size, spacing, colony size and microstructure were determined using optical microscopy (OM) and scanning electron microscopy (SEM) while the structure of the amorphous SiO2 was characterized by X-ray diffraction (XRD). The microstructure results are compared and contrasted with silica aerogel obtained through conventional processing using supercritical CO2.

Defect structure and chemistry of (Ca x Sr 1-x ) n+1 Ti n 0 3n+1 layer perovskites

1991 ◽  
Vol 336 (1644) ◽  
pp. 541-569 ◽  
Keyword(s):  
Neutron Diffraction ◽  
Alkaline Earth ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Oxide Superconductors ◽  
Orthorhombic Symmetry ◽  
X Ray ◽  
Resolution Electron ◽  
The Stability

The Ruddlesden-Popper structural family is constructed from ordered intergrowths of rocksalt type (AX) layers with perovskite (ABX 3 ) blocks of varying widths, yielding phases with the general formula n ABX 3 AX where 1 < n < ∞ In this article, the characterization of (Ca x Sr 1-x ) n+1 Ti n O 3n+1 layer perovskites by powder X-ray and neutron diffraction and high resolution electron microscopy is described. These phases undergo a phase transition from tetragonal to orthorhombic symmetry at x = 0.65. Structure solutions of neutron diffraction data are presented for the end-member phases Sr 3 Ti 2 O 7 (I4/mmm), Ca 3 Ti 2 O 7 (Ccm2 1 ) and Ca 4 Ti 3 O 10 (Pcab). Refinement of the mixed alkaline earth preparation (Ca 0.85 Sr 0.15 ) 4 Ti 3 O 10 showed that Sr partitioned preferentially to the perovskite blocks rather than the rocksalt layers. Ordered and disordered intergrowths of rocksalt layers were found on the{101} orth = {100} tet perovskite planes with extensive disorder most prevalent in samples annealed for short periods (less than 24 hours). Evidence is presented for the existence of V"A and V"," point defects in the intermediate structures that precede the formation of ordered layer sequences. These data are discussed in terms of existing thermodynamic and structural information. For generalized Ruddlesden Popper phases the relation between chemistry and symmetry is reviewed and factors contributing to the stability of different n -members enunciated. For completeness, the (Ca x Sr 1-x ) n+1 Ti n O 3n+1 perovskites are considered as the structural prototypes of the oxide superconductors being a subset of an extended n ABX 3 mAX Ruddlesden-Popper family.

Pushing the limits: an instrument for hard X-ray imaging below 20 nm

2015 ◽  
Vol 22 (2) ◽  
pp. 336-341 ◽  
Author(s):  
E. Nazaretski ◽  
K. Lauer ◽  
H. Yan ◽  
N. Bouet ◽  
J. Zhou ◽  
...  
Keyword(s):  
3D Imaging ◽  
X Ray ◽  
Ongoing Effort ◽  
X Ray Imaging ◽  
Synchrotron Facility ◽  
Imaging Resolution ◽  
Materials Used ◽  
The Stability ◽  
20 Nm ◽  
Non Destructive

Hard X-ray microscopy is a prominent tool suitable for nanoscale-resolution non-destructive imaging of various materials used in different areas of science and technology. With an ongoing effort to push the 2D/3D imaging resolution down to 10 nm in the hard X-ray regime, both the fabrication of nano-focusing optics and the stability of the microscope using those optics become extremely challenging. In this work a microscopy system designed and constructed to accommodate multilayer Laue lenses as nanofocusing optics is presented. The developed apparatus has been thoroughly characterized in terms of resolution and stability followed by imaging experiments at a synchrotron facility. Drift rates of ∼2 nm h−1accompanied by 13 nm × 33 nm imaging resolution at 11.8 keV are reported.

scholarly journals Minimizing experimental artefacts in synchrotron-based X-ray analyses of Fe speciation in tissues of rice plants

2019 ◽  
Vol 26 (4) ◽  
pp. 1272-1279 ◽  
Author(s):  
Peng Wang ◽  
Brigid A. McKenna ◽  
Neal W. Menzies ◽  
Cui Li ◽  
Chris J. Glover ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Plant Root ◽  
Experimental Conditions ◽  
X Ray ◽  
Freeze Dried ◽  
Fe Speciation ◽  
Root Tissues ◽  
X Ray Absorption ◽  
Beam Damage

Iron (Fe) plays an important role within environmental systems. Synchrotron-based X-ray approaches, including X-ray absorption spectroscopy (XAS), provide powerful tools for in situ analyses of Fe speciation, but beam damage during analysis may alter Fe speciation during its measurement. XAS was used to examine whether experimental conditions affect the analysis of Fe speciation in plant tissues. Even when analyzed in a cryostat at 12 K, it was found that FeIII can rapidly (within 0.5–1 min) photoreduce to FeII, although the magnitude of photoreduction varied depending upon the hydration of the sample, the coordination chemistry of the Fe, as well as other properties. For example, photoreduction of FeIII was considerably higher for aqueous standard compounds than for hydrated plant-root tissues. The use of freeze-dried samples in the cryostat (12 K) markedly reduced the magnitude of this FeIII photoreduction, and there was no evidence that the freeze-drying process itself resulted in experimental artefacts under the current experimental conditions, such as through the oxidation of FeII, although some comparatively small differences were observed when comparing spectra of hydrated and freeze-dried FeII compounds. The results of this study have demonstrated that FeIII photoreduction can occur during X-ray analysis, and provides suitable conditions to preserve Fe speciation to minimize the extent of beam damage when analyzing environmental samples. All studies utilizing XAS are encouraged to include a preliminary experiment to determine if beam damage is occurring, and, where appropriate, to take the necessary steps (such as freeze drying) to overcome these issues.

scholarly journals Shelf-Life Evaluation and Lyophilization of PBCA-Based Polymeric Microbubbles

Pharmaceutics ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 433 ◽  
Author(s):  
Tarun Ojha ◽  
Vertika Pathak ◽  
Natascha Drude ◽  
Marek Weiler ◽  
Dirk Rommel ◽  
...  
Keyword(s):  
Shelf Life ◽  
Rhodamine B ◽  
Freeze Drying ◽  
Pharmaceutical Products ◽  
Acoustic Properties ◽  
Signal Generation ◽  
Freeze Dried ◽  
Different Temperatures ◽  
The Stability ◽  
Commercial Platform

Poly(n-butyl cyanoacrylate) microbubbles (PBCA-MB) are extensively employed for functional and molecular ultrasound (US) imaging, as well as for US-mediated drug delivery. To facilitate the use of PBCA-MB as a commercial platform for biomedical applications, it is important to systematically study and improve their stability and shelf-life. In this context, lyophilization (freeze drying) is widely used to increase shelf-life and promote product development. Here, we set out to analyze the stability of standard and rhodamine-B loaded PBCA-MB at three different temperatures (4 °C, 25 °C, and 37 °C), for a period of time of up to 20 weeks. In addition, using sucrose, glucose, polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG) as cryoprotectants, we investigated if PBCA-MB can be lyophilized without affecting their size, concentration, US signal generation properties, and dye retention. Stability assessment showed that PBCA-MB remain largely intact for three and four weeks at 4 °C and 25 °C, respectively, while they disintegrate within one to two weeks at 37 °C, thereby compromising their acoustic properties. Lyophilization analyses demonstrated that PBCA-MB can be efficiently freeze-dried with 5% sucrose and 5% PVP, without changing their size, concentration, and US signal generation properties. Experiments involving rhodamine-B loaded MB indicated that significant dye leakage from the polymeric shell takes place within two to four weeks in case of non-lyophilized PBCA-MB. Lyophilization of rhodamine-loaded PBCA-MB with sucrose and PVP showed that the presence of the dye does not affect the efficiency of freeze-drying, and that the dye is efficiently retained upon MB lyophilization. These findings contribute to the development of PBCA-MB as pharmaceutical products for preclinical and clinical applications.

Preparation and characterization of dried cellulose nanofibrils

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jianping Ni ◽  
Chen Gong ◽  
Zhenghua Su ◽  
Chao Tian
Keyword(s):  
Spray Drying ◽  
Freeze Drying ◽  
Cellulose Nanofibrils ◽  
Time Dependent ◽  
X Ray ◽  
Original State ◽  
Final Mass ◽  
Freeze Dried ◽  
Spray Dried

Abstract One of the main manufacturing challenges is to obtain dried cellulose nanofibrils (CNFs) so that they can be cost effectively transported to customers. This work presents a study on using two methods of drying: freeze drying and spray drying; these dried CNFs were then characterized. The dried CNFs from either freeze drying or spray drying could not recover their original state after simple re-dispersion in water. Compared to spray dried CNFs, the microstructure of the freeze dried CNFs remained in a better shape. This was because the packing of nanofibrils as a result of freeze drying was not as tight as that from spray drying. It was demonstrated by the lower final mass residue and crystallinity of the freeze-dried CNFs, which led to better re-dispersion in water. X-ray diffractometry proved the occurrence of aggregation/hornification of the dried CNFs with increased crystallinity. Time-dependent sedimentation confirmed that the dried CNFs were incapable of forming stable water-re-dispersible suspensions.

scholarly journals Soft X-ray induced radiation damage in thin freeze-dried brain samples studied by FTIR microscopy

2020 ◽  
Vol 27 (5) ◽  
pp. 1218-1226
Author(s):  
Artur D. Surowka ◽  
A. Gianoncelli ◽  
G. Birarda ◽  
S. Sala ◽  
N. Cefarin ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Biological Sample ◽  
Radiation Doses ◽  
Complex Interplay ◽  
Ftir Microscopy ◽  
Tissue Samples ◽  
X Ray ◽  
Freeze Dried ◽  
Resolution Limits ◽  
First Time

In order to push the spatial resolution limits to the nanoscale, synchrotron-based soft X-ray microscopy (XRM) experiments require higher radiation doses to be delivered to materials. Nevertheless, the associated radiation damage impacts on the integrity of delicate biological samples. Herein, the extent of soft X-ray radiation damage in popular thin freeze-dried brain tissue samples mounted onto Si3N4 membranes, as highlighted by Fourier transform infrared microscopy (FTIR), is reported. The freeze-dried tissue samples were found to be affected by general degradation of the vibrational architecture, though these effects were weaker than those observed in paraffin-embedded and hydrated systems reported in the literature. In addition, weak, reversible and specific features of the tissue–Si3N4 interaction could be identified for the first time upon routine soft X-ray exposures, further highlighting the complex interplay between the biological sample, its preparation protocol and X-ray probe.

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