Standard Sample Holder Research Articles

ASMI: An automated, low-cost indenter for soft matter

The automated soft matter indenter (ASMI) is a platform for rapidly performing mechanical characterization of samples with elastic moduli in the range 7 kPa to 67 MPa with a sample acquisition time between 1 and 10 min. It is a low-cost system based upon open-source software, a modified mill, and an educational force sensor with a total bill of materials <$500. This system tests batches of up to 96 samples based on a standard well-plate sample holder without requiring any human intervention. Using the ASMI, users can obtain mechanical data in a programmable manner that enables high-throughput workflows, precisely testing time-dependent phenomena, and integration with other processing steps for closed-loop optimization.

SOLEIL: single-objective lens inclined light sheet localization microscopy.

High-NA light sheet illumination can improve the resolution of single-molecule localization microscopy (SMLM) by reducing the background fluorescence. These approaches currently require custom-made sample holders or additional specialized objectives, which makes the sample mounting or the optical system complex and therefore reduces the usability of these approaches. Here, we developed a single-objective lens-inclined light sheet microscope (SOLEIL) that is capable of 2D and 3D SMLM in thick samples. SOLEIL combines oblique illumination with point spread function PSF engineering to enable dSTORM imaging in a wide variety of samples. SOLEIL is compatible with standard sample holders and off-the-shelve optics and standard high NA objectives. To accomplish optimal optical sectioning we show that there is an ideal oblique angle and sheet thickness. Furthermore, to show what optical sectioning delivers for SMLM we benchmark SOLEIL against widefield and HILO microscopy with several biological samples. SOLEIL delivers in 15 μm thick Caco2-BBE cells a 374% higher intensity to background ratio and a 54% improvement in the estimated CRLB compared to widefield illumination, and a 184% higher intensity to background ratio and a 20% improvement in the estimated CRLB compared to HILO illumination.

SpheroidPicker for automated 3D cell culture manipulation using deep learning

Recent statistics report that more than 3.7 million new cases of cancer occur in Europe yearly, and the disease accounts for approximately 20% of all deaths. High-throughput screening of cancer cell cultures has dominated the search for novel, effective anticancer therapies in the past decades. Recently, functional assays with patient-derived ex vivo 3D cell culture have gained importance for drug discovery and precision medicine. We recently evaluated the major advancements and needs for the 3D cell culture screening, and concluded that strictly standardized and robust sample preparation is the most desired development. Here we propose an artificial intelligence-guided low-cost 3D cell culture delivery system. It consists of a light microscope, a micromanipulator, a syringe pump, and a controller computer. The system performs morphology-based feature analysis on spheroids and can select uniform sized or shaped spheroids to transfer them between various sample holders. It can select the samples from standard sample holders, including Petri dishes and microwell plates, and then transfer them to a variety of holders up to 384 well plates. The device performs reliable semi- and fully automated spheroid transfer. This results in highly controlled experimental conditions and eliminates non-trivial side effects of sample variability that is a key aspect towards next-generation precision medicine.

Automated device for continuous stirring while sampling in liquid chromatography systems

Ultra-performance liquid chromatography is a common analysis tool, and stirring is common in many laboratory setups. Here we show a device which enables continuous stirring of samples whilst inside an ultra-performance liquid chromatography system. Utilizing standard magnetic stirring bars that fit standard vials, the device allows for the automation of experimental setups that require stirring. The device is designed such that it can replace the standard sample holder and fits in its place, while being battery operated. The use of three-dimensional (3D) printing and commercially available parts enables low-effort and low-cost device production, as well as easy modifications. Testing the device was performed by video analysis and by following the kinetics of a dynamic combinatorial library that is known to be exquisitely sensitive to agitation, as a result of involving a fiber growth-breakage mechanism. Design files and schematics are provided.

The Evaluation of Syngas Loss from Disposable Syringe Sampling System: A Case Study

The main advantage of standard gas sampling methods is their capability to keep a consistent gas composition from sampling till analysis. On the other hand, the disadvantages include the price and possible fragility of the sampling equipment, and the speed of sampling. Thus, a new tool was required that should have low cost, could be used for fast sampling and during fieldwork. Disposable plastic syringes fulfil all these requirements with the additional advantage that they can be used multiple times to take gas samples. With the utilisation of 3-way stopcocks, a filter media and a butterfly needle, a simple but efficient sampling system was prepared. Even though the holding time of certain components is not as high as it is for a standard sample holder, the precise analysis of the gas samples is possible. Syringes have been successfully utilised in the field of applied pyrolysis, for small and pilot scale experiments, and can even be used in industrial environment.

Quantification of melamine in infant formula using a handheld Raman spectrometer – Performance boost with customized Arduino-controlled rotation setup

This study investigated the performance of a handheld Raman spectrometer in quantifying melamine in infant formula. Furthermore, the spectrometer's standard stationary sample holder was compared to a custom-built sample rotation unit. The Raman spectra were divided into a calibration set, which was used to construct the partial least squares regression (PLS-R) models, and a test set, which served the purpose of evaluating the model performance with independent samples. It was found that it was possible to reduce the prediction error of melamine in infant formula by up to about 70% using the simple in-house constructed rotation setup. Compared to the rotation setup, even an increased number of point measurements using the spectrometer's standard sample holder was not able to compensate for the lack of representative sample presentation of the inhomogeneous solid mixture to the Raman spectrometer. Moreover, it was found that the custom-built rotation unit enabled faster sample measurements by an adaption of spectrometer parameters. At the same time, the prediction error of the test set samples was kept far lower than with the stationary setup.

Interferometric characterization of rotation stages for X-ray nanotomography.

The field of three-dimensional multi-modal X-ray nanoimaging relies not only on high-brilliance X-rays but also on high-precision mechanics and position metrology. Currently available state-of-the-art linear and rotary drives can provide 3D position accuracy within tens to hundreds of nm, which is often insufficient for high resolution imaging with nanofocused X-ray beams. Motion errors are especially troublesome in the case of rotation drives and their correction is more complicated and relies on the metrology grade reference objects. Here we present a method which allows the characterisation and correction of the radial and angular errors of the rotary drives without the need for a highly accurate metrology object. The method is based on multi-probe error separation using fiber-laser interferometry and uses a standard cylindrical sample holder as a reference. The obtained runout and shape measurements are then used to perform the position corrections using additional drives. We demonstrate the results of the characterization for a piezo-driven small rotation stage. The error separation allowed us to measure the axis runout to be approximately ±1.25 μm, and with active runout compensation this could be reduced down to ±42 nm.

Small‐Scale Thermal Studies of Volatile Homemade Explosives

AbstractSeveral homemade or improvised explosive mixtures that either contained volatile components or produced volatile products were examined using standard small‐scale safety and thermal (SSST) testing that employed differential scanning calorimetry (DSC) techniques (constant heating rate and standard sample holders). KClO3 and KClO4 mixtures with dodecane exhibited different enthalpy behavior when using a vented sample holder in contrast to a sealed sample holder. The standard configuration produced profiles that exhibited only endothermic transitions. The sealed system produced profiles that exhibited additional exothermic transitions absent in the standard configuration produced profiles. When H2O2/fuel mixtures were examined, the volatilization of the peroxide (endothermic) dominated the profiles. When a sealed sample holder was used, the energetic releases of the mixture could be clearly observed. For AN and AN mixtures, the high temperature decomposition appears as an intense endothermic event. Using a nominally sealed sample holder also did not adequately contain the system. Only when a high‐pressure rated sample holder was used the high temperature decomposition of the AN could be detected as an exothermic release. The testing was conducted during a proficiency (or round‐robin type) test that included three U.S. Department of Energy and two U.S. Department of Defense laboratories. In the course of this proficiency test, certain HMEs exhibited thermal behavior that was not adequately accounted for by standard techniques. Further examination of this atypical behavior highlighted issues that may have not been recognized previously because some of these materials are not routinely tested. More importantly, if not recognized, the SSST testing results could lead to inaccurate safety assessments. This study provides examples, where standard techniques can be applied, and results can be obtained, but these results may be misleading in establishing thermal properties.

Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system

We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (~1 eV) in the core level binding energies was observed.

Versatile scanning tunneling microscopy with 120 ps time resolution

We describe a fully ultra-high vacuum compatible scanning tunneling microscope (STM) optimized for radio-frequency signals. It includes in-situ exchangeable tips adapted to high frequency cabling and a standard sample holder, which offer access to the whole range of samples typically investigated by STM. We demonstrate a time resolution of 120 ps using the nonlinear I(V)-characteristic of the surface of highly oriented pyrolithic graphite. We provide atomically resolved images in pulse mode related to a spatially varying nonlinearity of the local density of states of the sample, thus, demonstrating the possible spatial resolution of the instrument in pulse mode. Analysis of the noise reveals that changes in the tunneling junction of 50 pA are dynamically detectable at 120 ps time resolution.

Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy

The recent development for in situ transmission electron microscopy, which allows imaging through liquids with high spatial resolution, has attracted significant interests across the research fields of materials science, physics, chemistry and biology. The key enabling technology is a liquid cell. We fabricate liquid cells with thin viewing windows through a sequential microfabrication process, including silicon nitride membrane deposition, photolithographic patterning, wafer etching, cell bonding, etc. A liquid cell with the dimensions of a regular TEM grid can fit in any standard TEM sample holder. About 100 nanoliters reaction solution is loaded into the reservoirs and about 30 picoliters liquid is drawn into the viewing windows by capillary force. Subsequently, the cell is sealed and loaded into a microscope for in situ imaging. Inside the TEM, the electron beam goes through the thin liquid layer sandwiched between two silicon nitride membranes. Dynamic processes of nanoparticles in liquids, such as nucleation and growth of nanocrystals, diffusion and assembly of nanoparticles, etc., have been imaged in real time with sub-nanometer resolution. We have also applied this method to other research areas, e.g., imaging proteins in water. Liquid cell TEM is poised to play a major role in revealing dynamic processes of materials in their working environments. It may also bring high impact in the study of biological processes in their native environment.

Revealing Dynamic Processes of Materials in Liquids Using Liquid Cell Transmission Electron Microscopy

The recent development for in situ transmission electron microscopy, which allows imaging through liquids with high spatial resolution, has attracted significant interests across the research fields of materials science, physics, chemistry and biology. The key enabling technology is a liquid cell. We fabricate liquid cells with thin viewing windows through a sequential microfabrication process, including silicon nitride membrane deposition, photolithographic patterning, wafer etching, cell bonding, etc. A liquid cell with the dimensions of a regular TEM grid can fit in any standard TEM sample holder. About 100 nanoliters reaction solution is loaded into the reservoirs and about 30 picoliters liquid is drawn into the viewing windows by capillary force. Subsequently, the cell is sealed and loaded into a microscope for in situ imaging. Inside the TEM, the electron beam goes through the thin liquid layer sandwiched between two silicon nitride membranes. Dynamic processes of nanoparticles in liquids, such as nucleation and growth of nanocrystals, diffusion and assembly of nanoparticles, etc., have been imaged in real time with sub-nanometer resolution. We have also applied this method to other research areas, e.g., imaging proteins in water. Liquid cell TEM is poised to play a major role in revealing dynamic processes of materials in their working environments. It may also bring high impact in the study of biological processes in their native environment.

Influence of Colour Filter on Reaction Products from Mo and W Heated to 2000&amp;deg;C by Concentrated Solar Beam in N&lt;SUB&gt;2&lt;/SUB&gt; Gas Environment in a Solar Furnace at PROMES-CNRS

In a preceding work, we reported attempts of synthesizing nitride of d-group transition metals including Ti, V, Nb and Ta using a solar furnace at PROMES-CNRS. In standard solar furnace experimental setup, graphite crucible is used as the sample holder on account of its resistance against high temperature and thermal shock. Plume of C2 radical with high chemical activity a(C) of C was reported to yield from graphite crucible under irradiation of concentrated solar beam. Thus, synthesis of pure metal nitride MN was not successful in the preceding work done in N2 gas environment heated by solar beam irradiation under standard experimental setup. To overcome this problem of undesired carburization in solar furnace, insertion of colour filter in the path of solar beam was tried and it was found that the C2 radical yield from the graphite crucible was effectively suppressed by insertion of Sky blue filter and carbo-nitride M(C,N) with comparatively low C-content was synthesized for Ti, V, Nb and Ta at 2000°C in N2 gas environment while, without the Sky blue filter, M(C,N) with high C-content and low N-content was synthesized under the otherwise comparable conditions of temperature and nitrogen partial pressure. These evidences appeared to suggest that nitride synthesis might be realized in standard solar furnace experimental setup using standard sample holder made of graphite by insertion of Sky blue filter. In the present work, reaction products from Mo and W in N2 gas environment under solar heating to 2000°C were characterized and effectiveness of the Sky blue filter for suppression of C2 radical yield from the graphite crucible was ascertained.

Determination of the flammability properties of polymeric materials: A novel method

Standard flammability tests, like the Cone Calorimeter, were developed several decades ago and provided sufficient flammability data for the purposes of the time. However, recent pyrolysis models have revealed the limitations of the standard test in providing adequate data for current flammability analysis and modelling. This paper reviews the assumptions in the standard test and proposes a novel sample holder for the cone calorimeter which incorporates a large block of aluminium at the rear face of the sample under test. This allows the heat losses at the rear face of the sample to be measured precisely and enables more accurate calculation of the material flammability properties. Tests of PA6 and a nano-composite of PA6 & Cloisite 30B, carried out using the standard and new sample holders, are presented and discussed. The peak of high heat release rate observed in standard tests of PA6 is not observed using the novel sample holder, where the burning behaviour of PA6 and the nano-composite material are largely similar. The implications of these observations are discussed.

High-pressure optical cell system for online luminescence spectrum research

An optical cell system was developed for online research into the luminescence spectrum under conditions of extremely high hydrostatic pressure up to 60 MPa. The optical cell, which had three 8 mm thick sapphire windows 16 mm in diameter, was mounted directly onto a fluorescence spectrometer. Hydrostatic pressure was achieved through a hand pump and monitored through a pressure sensor. The optical cell system could be used separately. And more importantly, the system could be connected to a high-pressure flowing system for online flowing luminescence measurement. For system validation, fluorescence spectra of Rose Bengal solution using the high-pressure cell were compared with the standard sample holder. Using the system, fluorescence spectra of Rose Bengal dissolved in distilled water were measured under different pressures at room temperature. The fluorescence intensity of Rose Bengal solution changed with pressures, but the peak positions were almost the same.

Design of a compensated signal rod for low magnetic moment sample measurements with a vibrating sample magnetometer

A zero-signal sample holder is proposed for the measurement of weak magnetic signals with vibrating sample magnetometers. With proper shape of the support rod, a nearly vanishing signal can be obtained as a function of the magnetic field and the temperature. In particular, it is shown that the addition of an extra part to a standard glass sample holder can reduce the diamagnetic signal by more than three orders of magnitude with no noise increase. The proposed method is applicable to field, temperature, and angular measurements; it is also ideally suited to direct measurement of nanometer thick magnetic layers deposited on much thicker diamagnetic substrates.

Vapor Pressure and Enthalpy of Vaporization of Fentanyl

This paper describes the application of thermogravimetry including conventional thermobalance and standard sample holders for the estimation of vapor pressure and related thermodynamic properties of a potent narcotic analgesic, fentanyl (CAS No. 437-38-7). For this study, benzoic acid was used as a reference material to calibrate the thermogravimetric analysis (TGA) instrument and experimental conditions used. The relationship between the isothermal sublimation rates of benzoic acid determined at different temperatures and the corresponding literature vapor pressure values was established, and the correlation equation thus obtained was used for the estimation of vapor pressure of fentanyl. By adopting this procedure, the vapor pressure of fentanyl was estimated at different temperatures from T = (423.15 to 493.15) K. Extrapolation of the measured data to T = 298.15 K gave the vapor pressure of subcooled fentanyl and estimated it to be (4.6 ± 2.7)·10−6 Pa. The corresponding solid phase vapor pressure of fentanyl was calculated to be (5.9 ± 4.7)·10−7 Pa after taking the enthalpy of fusion into consideration. Related thermodynamic properties, viz., enthaply of vaporization and normal boiling points, were also estimated from the vapor pressure−temperature curve.

A calorimetric study of wildland fuels

The burning of two species of pine needles: Pinus halepensis and Pinus pinaster, was studied to characterize the behavior of the forest floor in wildland fires. These fuels are representative of the Mediterranean ecosystem and have very different shapes and surface-to-volume ratios. Calorimetry was performed using the FM-global fire propagation apparatus (FPA). To better understand the effects of transport in the fuel beds, the standard sample holder was replaced by a holder that allowed for the porous properties of the fuel to be studied in a systematic manner. These holders were designed with holes on the surface to allow for different air flow rates to pass through the holder and into the fuel sample. These characteristics created different internal fuel bed conditions and were the first such tests that could be identified that examined transport on this level in these types of wildland fuels. Tests were conducted under natural convection and forced flow. The test series results were analyzed with respect to the direct values of the measured variables and calculated values of heat release rate. Discrete variables of time to ignition, duration of flaming combustion and peak heat release rate were compared using an analysis of variance method. As the experiments were conducted under well-ventilated conditions, the heat release rate calculated by calorimetry was compared to mass loss rate and heat of combustion. CO concentration in time proved to be a good indicator of the combustion dynamics in the fuel bed. Heat release rate, time to ignition and time to reach peak heat release rate indicated a strong dependence on flow conditions and on fuel specie. It was shown that the transport processes in the fuel beds had a significant effect on the burning characteristics.

Automation of sample mounting for macromolecular crystallography

A standard sample holder and vial for cryocooled macromolecular crystals has been defined for use with robotic sample changers. This SPINE standard sample holder is a modified version, with added features and specifications, of sample holders in common use. In particular, the SPINE standard meets the precision required for automatic sample exchange and includes a cap that is identified by a two-dimensional datamatrix code as well as an optional vial. At the ESRF, the sample holder standard is in use with the EMBL/ESRF/BM14 robotic sample changer (SC3) which is installed on eight beamlines. The SC3 can hold up to 50 crystals stored in five baskets. A datamatrix reader in the SC3 ensures safe management of the sample flow and facilitates fully automatic screening and characterization of samples. Tools for handling and transporting 50 samples in a dry shipping dewar have been developed. In addition to the SC3, the SPINE sample holder is currently compatible with a number of other robotic sample changers.

Design of a UHV-compatible rf plasma source and its application to self-assembled layers of CoPt3 nanoparticles

A compact, versatile, and simple rf plasma source with capacitive coupling compatible to ultrahigh vacuum (UHV) requirements was designed and built to allow sequences of sample surface modification in plasma and surface preparation and analysis in vacuum without breaking the vacuum. The plasma source was operated at working pressures of less than 1 to a few millibars. Sample transfer to UHV was performed at pressures around 10−9mbar. For easy integration into an existing UHV setup, the sample recipient and transfer system were made to accept standard commercial sample holders. Preliminary experiments were performed by exposing monolayers of colloidal CoPt3 nanoparticles to oxygen and hydrogen plasmas. The structural and chemical effects of the plasma treatments were analyzed with scanning electron microscopy and x-ray photoelectron spectroscopy.