Solid Samples Research Articles

An optimized protocol for pig intestinal mucosa proteomics

The overall well-being of organisms is widely recognized to be closely intertwined with their intestinal health. The intestinal mucosal layer plays a pivotal role in ensuring the proper functioning of the intestine, a fact observed not only in humans but also in animals like pigs. Any alterations to the mucosal layer of a pig's intestine can potentially disrupt its functionality, thereby impacting the animal's health and productivity. Mass spectrometry-based proteome analysis serves as a valuable tool in investigating the intricate dynamics of the proteome within the intestinal mucosa. Such studies hold promise in uncovering causal relationships between mucosal changes and overall health outcomes in pigs. It is anticipated that insights gathered from proteome studies will inform future strategies aimed at enhancing the health and productivity of pigs. However, the research field lacks a standardized and detailed method to extract proteins from pig intestinal mucosa and prepare proteins for proteome analysis. In the present study, we evaluated three alternative S-Trap-based protocols for analyzing ileal mucosal scrapings from pigs. Samples were either freeze-dried and treated as solid samples or ground in liquid nitrogen, categorized as either solid or liquid samples. In our analysis, a total of 2840 proteins were identified across all samples. Through statistical analysis and gene ontology examinations, we investigated potential differences between the three approaches. Even though our findings revealed no significant differences among the three methods, we propose the use of the protocol wherein samples are freeze-dried and treated as solid for protein extraction. This protocol stands out as the most convenient and practical option, offering ease of use and ensuring consistent and reliable results. By establishing a standardized approach, we aim to advance research efforts in understanding pig intestinal health. SignificanceThe development of an optimized protocol for protein extraction of intestinal mucosal scrapings in pigs addresses a gap in the field and enhances future research on pig intestinal health. By use of the protocol and mass spectrometry-based proteome analysis, valuable insights for improving the health and productivity of pigs can be presented. Studying the complex dynamics of the proteome within the intestinal mucosa, potentially identifying links between mucosal changes and health outcomes, provides us with information about the critical connection between intestinal health and the overall well-being and productivity of pigs. By creating a standardized approach, consistent, reliable, and reproducible results can be obtained for this type of research.

A reusable QCM biosensor with stable antifouling nano-coating for on-site reagent-free rapid detection of E. coli O157:H7 in food products

Numerous biosensors have shown exceptional analytical performance under laboratory conditions, yet only a few are capable of on-site use with complex, non-model samples while exhibiting reliable analytical performance. Here, we present a new portable biosensor for the rapid (30 min) and accurate detection of bacterial agents in “real-world” food samples, which are originally in either solid or liquid form. The biosensor combines well-established quartz crystal microbalance (QCM) technology, with innovative terpolymer brush nano-coatings on the sensing surface to efficiently reduce non-specific fouling from food samples. Following reagent-free sample preparation, where solid food samples are homogenized, we validated the sensor's detection capabilities on native pathogenic Escherichia coli O157:H7 (E. coli O157:H7) in hamburgers, Czech dumplings, and milk. We achieved limits of detection (LOD), as low as 7.5 × 102 CFU/mL in milk, a value approaching fundamental QCM limits, using a simple direct detection assay format. The biosensor's exceptional reusability was demonstrated through 60 sequential hamburger sample injections, resulting in only a minor LOD shift toward the end of series. A 10-min sonication treatment during sample preparation significantly enhanced sensitivity for E. coli O157:H7 in hamburgers and dumplings, yielding LODs as low as 3.1 × 10³ CFU/mL and 2.6 × 10⁴ CFU/mL, respectively. For on-site analysis, we integrated the nano-coated sensing chip into a custom-built four-channel portable QCM biosensor with an optimized microfluidic system, which can be produced on a scale suitable for practical deployment.

Cyclic Ion Mobility of Isomeric New Psychoactive Substances Employing Characteristic Arrival Time Distribution Profiles and Adduct Separation.

Analysis of new psychoactive substances (NPS), which is essential for toxicological and forensic reasons, can be made complicated by the presence of isomers. Ion mobility has been used as a standalone technique or coupled to mass spectrometry to detect and identify NPS. However, isomer separation has so far chiefly relied on chromatography. Here we report on the determination of isomeric ratios using cyclic ion mobility-mass spectrometry without any chromatographic separation. Isomers were distinguished by mobility separation of lithium adducts. Alternatively, we used arrival time distribution (ATD) profiles that were characteristic of individual isomers and were acquired for protonated molecules or fragment ions. Both approaches provided comparable results. Calculations were used to determine the structures and collision cross sections of both protonated and lithiated isomers that accurately characterized their ion mobility properties. The applicability of ATD profiles to isomer differentiation was demonstrated using direct infusion and flow injection analysis with electrospray of solutions, as well as desorption electrospray of solid samples. Data processing was performed by applying multiple linear regression to the ATD profiles. Using the proposed ATD profile-based approach, the relationships between the determined and given content of isomers showed good linearity with coefficients of determination typically greater than 0.99. Flow injection analysis using an autosampler allowed us to rapidly determine isomeric ratios in a sample containing two isomeric pairs with a minor isomer of 10% (determined 9.3% of 3-MMC and 11.0% of 3-FMC in a mixture with buphedrone and 4-FMC). The proposed approach is not only useful for NPS, but also may be applicable to small isomeric molecules analyzed by ion mobility when complete separation of isomers is not achieved.

STUDY OF NONVERBAL COMMUNICATION OF CONFERENCE INTERPRETERS’ LINGUISTIC PERSONALITY

The article is devoted to the relevance and significance of nonverbal communication in a comprehensive approach to the study of the linguistic personality of a conference interpreter. The author explains the use of the communicative-functional approach to the analysis of verbal and nonverbal behaviour of the interpreter’s linguistic personality. The hypothesis of the study brings out that the nonverbal behaviour of the interpreter’s linguistic personality is determined by the content of the translated utterance, the interpreter’s internal motivation and intention (the pragmatic level of the linguistic personality), and it is consistently proved that nonverbal means shall be considered as part of the structural model of the linguistic personality, influencing the verbal representation of the linguistic personality. The author analyses a nonverbal sign (at its beginning, middle and end of its expression) and a translation syntagm as minimal units of study. The units of the study were collected by solid sampling from 14 video recordings of interpretation series, total study includes 105 minutes with records of nonverbal signs used by linguistic personality the interpreters participated in the study. As a result, the author classified nonverbal signs into vegetatives and somatives, and she structurally described the content of the groups of kinesic somatives, oculesic somatives and prosodic somatives, presenting the semantic content of nonverbal signs; within kinesic somatives, the author described a subgroup of comfort-gestures. The paper concludes about the prospect of further study of nonverbal communication and its importance for the study of linguistic personality in general.

Effect of impurity concentration on the precipitation of atorvastatin calcium under microgravity on the International Space Station

The influence of the concentration of impurities on the precipitation of atorvastatin calcium (ATC) under microgravity conditions at the International Space Station was investigated. An ATC mixture containing 0.0, 0.1, 0.3, or 1.0 % w/w of rosuvastatin calcium as an impurity was added to methanol, which readily dissolved the compounds. Microcapillaries filled with the ATC mother liquor were loaded into counter-diffusion cell tubes filled with pure water, a poor solvent for the mixture, and prepared as ATC mother liquor. The counter-diffusion cell tubes were placed in a warming device and launched to the International Space Station aboard a rocket. After 30 days of precipitation under microgravity, the solids were separated from the liquids, and their Raman spectra were measured. The Raman spectra of the orbited and control solid samples, precipitated under microgravity and normal gravity, respectively, displayed different peak intensities depending on the impurity. To demonstrate the effect of microgravity on ATC precipitation, Raman spectra of ATC precipitated with and without the impurity under microgravity and normal gravity were analyzed using principal component analysis. The Raman spectra were also quantitatively analyzed using partial least squares regression, for which the impurity was the objective variable, to investigate the intermolecular interactions between ATC and the impurity during precipitation. Microgravity was found to affect the crystal morphology and precipitation of impurity-containing ATC.

Wellbore cement alteration and roles of CO2 and shale during underground hydrogen storage

To mitigate climate change and adopt renewable energy, energy storage is crucial and can be done in the form of hydrogen gas (H2). Subsurface geologic reservoirs are positioned to store H2 on the largest scales for the longest terms of all potential options. However, H2 injection may boost reactions that consume hydrogen, generate undesired gases, and alter pore structures of geomedia. To explore the extent of H2-associated biotic reactions at a near wellbore location, four experiments were conducted under underground storage conditions with wellbore cement cores and, in most instances, shale samples submerged in synthetic formation brine. Post-reaction gas, aqueous, and solid phase samples were analyzed using olfactory screening and, later, gas chromatography (GC-MS), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM), and synchrotron micro-scale x-ray fluorescence (μ-XRF). Within a period of 16 weeks, hydrogen sulfide (H2S) was generated in systems containing both H2 and shale. XRF mapping identified a zone enriched in iron(II) and reduced sulfur along the rim of cement cross sections that was largely associated with CO2-induced cement carbonation. Shale did not show noticeable alteration, but there is evidence it contributed to the initial inoculation of the system and provided nutrients for microbes via water-rock interactions. This study considers both rock formations and wellbore cement not previously evaluated concurrently. Findings support understanding and modeling of H2-associated biogeochemical reactions during underground hydrogen storage.

Monitoring residual solvents in pharmaceutical products using a portable pre-concentration GC-PID

Pharmaceutical manufacturing utilizes solvents at different stages of production. Some of the harmful solvent residuals may be retained in the final product; therefore, they need to be monitored for quality control and to meet the regulation requirement. Here, a novel method capable of rapidly analyzing residual solvents in pharmaceutical products was developed using a compact-portable gas chromatography with a photoionization detector (GC-PID). The method consists of modified Tedlar® bag sampling, online pre-concentration, separation of volatiles by miniaturized GC, and micro-PID detection. The method detection limits of selected residual solvents were in the range of 26.00 – 52.03 pg/mL which is much lower than the pharmaceutical compliance concentration limits. Limits of detection > 520 pg of analyte per grams of sample was also determined for the over-the-counter drugs. The method performance showed rapid speed (5 min), linear calibration (r2 < 0.99), and repeatable retention time (RSD < 0.4 %). Direct analysis of residual solvents in solid samples was conducted without the need for complex sample preparation. The method validation using over-the-counter pharmaceutical products yielded excellent accuracy (recovery > 91.2 %) and precision (RSD < 6.5 %) for the selected residual solvents, including 1,4-dioxane, benzene, chlorobenzene, cyclohexane, xylenes, and toluene. This portable and rapid method could be deployed during the pharmaceutical drug manufacturing processes for quality control.

Gold content determination in small core-samples by instrumental neutron activation analysis

Application of instrumental neutron activation analysis (INAA) based on the relative method of concentration standardization was considered to determine Au content in small solid core-samples of the gold-bearing ores and rocks up to 10 g of the mass. The small core-samples about 10 mm in diameter and 22-23 mm in length were cut from the previously collected ore lumps or in-situ using a handheld drilling rig. The studied small core-samples and the polyethylene capsules of the same dimensions filled up with the corresponding certified reference material (CRM) were irradiated for 2 min by a lower density neutron flux with the help of the automated pneumatic transport system (PTS). Maximum mass and dimensions of the core-samples corresponded to the PTS design and to the conditions of its safe operation. A special device was made to fix the transport capsules in the stable counting geometry making possible to eliminate the influence of the neutron flux gradient during irradiation. Due to the substantial differences in CRM and solid sample densities, corrections for neutron self-shielding and for gamma-ray self-absorption by the core-samples were applied. The method was tried to analyze Au content in 170 small core-samples presenting different gold-bearing ores and country rocks from the Kazakhstan’s gold-barite-polymetallic deposit Maikain. This approach, rather simple methodically and requiring no unique equipment, can be used to assess gold resources together with the methods of geostatistics.

Quartz Enhanced Photoacoustic Spectroscopy on Solid Samples.

Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) is a technique in which the sound wave is detected by a quartz tuning fork (QTF). It enables particularly high specificity with respect to the excitation frequency and is well known for an extraordinarily sensitive analysis of gaseous samples. We have developed the first photoacoustic (PA) cell for QEPAS on solid samples. Periodic heating of the sample is excited by modulated light from an interband cascade laser (ICL) in the infrared region. The cell represents a half-open cylinder that exhibits an acoustical resonance frequency equal to that of the QTF and, therefore, additionally amplifies the PA signal. The antinode of the sound pressure of the first longitudinal overtone can be accessed by the sound detector. A 3D finite element (FE) simulation confirms the optimal dimensions of the new cylindrical cell with the given QTF resonance frequency. An experimental verification is performed with an ultrasound micro-electromechanical system (MEMS) microphone. The presented frequency-dependent QEPAS measurement exhibits a low noise signal with a high-quality factor. The QEPAS-based investigation of three different solid synthetics resulted in a linearly dependent signal with respect to the absorption.

Effect of solutionizing heat treatment on the structure and mechanical properties of silicon bronze (Cu-10wt%Si-2wt%Ni)

The effect of solutionizing temperature, soaking time, and quenching media on the structure and mechanical properties of silicon bronze (Cu-10wt%Si-2wt%Ni) has been examined. The samples were produced using the sand casting technique, machined to the required dimensions, and solutionized at temperatures of 700 oC, 800 oC, and 900 oC for 0.5, 1.5, 2.5, and 3.5 hrs and quenched in brine and oil respectively. The prepared as-cast and solution heat-treated samples were subjected to mechanical tests (hardness, and impact strength tests) as well as microstructural analysis. The results of the microstructural analysis revealed the presence of coarse grains and coarse sparse distribution of Ni2Si precipitate in the as-cast sample while the surface morphology of the heat-treated samples consisted of fine grains of intermetallic compounds evenly dispersed in the copper matrix. It was also observed that the microstructures of samples solutionized at lower temperatures (700 oC) revealed finer grains with better grain distributions compared with samples solutionized at higher temperatures (800 oC and 900 oC). These microstructural changes led to the improvement of the hardness and impact strength of the alloy. The hardness value of the as-cast sample 48.5 HRB, increased to 53.7 HRB and 57.8 HRB after solid solution heat treatment at 700 oC for 3.5 h and cooled in brine and oil, respectively. It was also observed that the hardness of the brine-cooled samples increased further to 72.45 HRB after 3.5 h at 900 oC. The results obtained also showed that the solid solution heat-treated samples gave an optimum impact strength value of 214 J/m3 and 183 J/m3 from the samples solutionized at 900 oC and 800 oC for 3.5 h and 1.5 h and cooled in brine and oil respectively. This was concluded to be a result of solid solution alpha and beta phases formed which improve energy absorption in the alloy.

Effect of cooling rate on the precipitation characteristics and growth mechanism of Bi3Ni in liquid lead‑bismuth eutectic

Austenitic stainless steel is a promising candidate structural material for direct contact components with lead‑bismuth eutectic (LBE) in lead-cooled fast reactor (LFR). However, the preferential dissolution of Ni from austenitic steels at low oxygen concentrations will lead to the precipitation of Ni-containing phases in the low-temperature parts of reactors, which has a risk of pipe clogging. In this paper, three samples, comprising one extracted from a corrosion tank after prolonged operation and two prepared, respectively, by quenching in liquid nitrogen and cooling in the furnace, were obtained to investigate the effect of cooling rate on the precipitation characteristics and growth mechanism of Bi3Ni that forms by the reaction of dissolved Ni and Bi in LBE. The results showed that rod-like Bi3Ni was found in all three Ni-containing LBE samples. As the cooling rate increased, the width of Bi3Ni decreased. The Bi3Ni in all three samples displayed a pseudo-hexagonal prismatic shape and had a typical faceted growth character; the cooling rate had no effect on the morphology of them. The crystallographic analysis showed that the growth axis of Bi3Ni was in the 〈010〉 direction, and the prism planes were composed of {001} and {101}. In addition, the precipitation of Bi3Ni inevitably increased the content of Pb7Bi3, which would in turn enhance the volumetric expansion of solid LBE samples. For the growth mechanism, Bi3Ni phases were controlled by the screw dislocation mechanism, with the step growth rate of the dislocation core being greater than that of the outer edges. Given the low cooling rate and low Ni content in the LBE coolant of reactors, the precipitation of Bi3Ni with a rod-like morphology seems to be inevitable.

Extraction and preconcentration of lead (II) in various water and food samples by orbital shaker-assisted magnetic solid phase extraction method using a new magnetic poly linoleic acid-polystyrene-PDMS block copolymer

The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7–84 μg L−1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 μg L−1, 1.7 μg L−1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g−1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.

Plastic-sleeve test method to measure autogenous and drying shrinkage in paste, mortar, and concrete: Test Results

The Plastic-Sleeve Test (PST) method of molding cylindrical specimens in plastic sleeves enables the measurement of autogenous and total shrinkage of pastes, mortars, and concretes. Photogrammetric tests confirmed that the linear support of the specimens with a temporary bottom support mold does not restrain deformation. Tests were performed to compare the PST versus corrugated tube methods and similar relative humidity and autogenous shrinkage results were obtained. The PST shows comparable CoV values to those of the corrugated tube test. The method presented provides solid circular cross-section samples, enabling control over entrapped air content, specimen shape, and bleeding effects, thereby ensuring the measurement method’s high repeatability. The PST showed a tighter seal than prismatic samples molded for total shrinkage testing according to EN 1367-4. Results indicate that the PST can effectively be used for molding samples intended for total shrinkage measurement. It is concluded that the PST method is an effective method to measure autogenous shrinkage and total shrinkage of cementitious materials.

Efficient separation of catechyl lignin from castor seed coats via molten salt hydrate

The excellent acid-resistant property of catechyl lignin (C-lignin) allows for its isolation from biomass with intact structure, making it an “ideal lignin” for valorization. In this study, an effective method was developed to separate C-lignin from castor seed coats using acidic molten salt hydrate of LiBr (LiBr-AMSH). Under recommended conditions (60 wt% LiBr solution with 60 mM HCl, 150 °C, and 1 h), 96 wt% of solid sample (based on Klason lignin in castor seed coats) was obtained. Structural characterization indicated that isolated C-lignin consisted of 99 % benzodioxane (BD) structures. Additionally, the optimal conditions led to the achievement of a C-lignin yield of 12.8 wt% (based on raw material), demonstrating a notable accomplishment in terms of productivity. This study provides a green and efficient procedure for extracting C-lignin from castor seed coats while paving the way for valorization.

Fine-needle aspiration technique under endoscopic ultrasound guidance: A technical approach for RNA profiling of pancreatic neoplasms.

Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) has been a longstanding challenge. The prognosis of patients with PDAC depends on the stage at diagnosis. It is necessary to identify biomarkers for the detection and differentiation of pancreatic tumors and optimize PDAC sample preparation procedures for DNA and RNA analysis. Most molecular studies are done using paraffin-embedded blocks; however, the integrity of DNA and RNA is often compromised in this format. Moreover, RNA isolated from human pancreatic tissue samples is generally of low quality, in part, because of the high concentration of endogenous pancreatic RNAse activity present. To assess the potential of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) to obtain specimens from pancreatic neoplasms for subsequent RNA molecular profiling, including next-generation sequencing (NGS). Thirty-four EUS-FNA samples were included in this study: PDAC (n = 15), chronic pancreatitis (n = 5), pancreatic cysts (n = 14), mucinous cysts (mucinous cystic neoplasia/intraductal papillary mucinous neoplasia) n = 7, serous cystic neoplasms n = 5, and pseudocysts n = 2. Cyst material consisted of cyst fluid and cyst wall samples obtained by through-the-needle biopsy (TTNB). Samples were stored at -80 °C until analysis. RNA purity (A260/230, A260/280 ratios), concentration, and integrity (RIN) were assessed. Real-time polymerase chain reaction was conducted on all samples, and small RNA libraries were prepared from solid mass samples. RNA was successfully extracted from 29/34 (85%) EUS-FNA samples: 100% pancreatic adenocarcinoma samples, 100% chronic pancreatitis samples, 70% pancreatic fluid cyst samples, and 50% TTNB samples. The relative expression of GAPDH and HPRT were obtained for all successfully extracted RNA samples (n = 29) including low-quality RNA specimens. Low concentration and nonoptimal RIN values (no less than 3) of RNA extracted from EUS-FNA samples did not prevent NGS library preparation. The suitability of cyst fluid samples for RNA profiling varied. The quality of RNA extracted from mucinous cyst fluid had a median RIN of 7.7 (5.0-8.2), which was compatible with that from solid neoplasms [6.2 (0-7.8)], whereas the quality of the RNA extracted from all fluids of serous cystic neoplasms and TTNB samples had a RIN of 0. The results demonstrate the high potential of EUS-FNA material for RNA profiling of various pancreatic lesions, including low-quality RNA specimens.

Rapid determination of germanium in lignite coal and coal-related solid byproducts by graphite furnace digestion inductively coupled plasma emission spectroscopy

This study developed a rapid and efficient graphite furnace digestion combined with inductively coupled plasma emission spectrometry (ICP-OES) method, enabling precise quantification of germanium (Ge) in coal and various coal-derived metallurgical byproducts across a broad concentration level (∼ppm-n%). The graphite furnace digestion conditions were examined intensively as a function of the acid amounts of HNO3 and HF (5–10 mL), temperature (80–180 °C), time (1–5 h), and acid drive methods (H3BO3 neutralization versus heating). Coal references including SARM 19, SARM 20, NIST SRM 1632e, and fly ash standard NIST SRM 2689 were tested. The optimum recovery of germanium was obtained when the HNO3 dosage, HF dosage, solid sample mass, temperature, and duration time were 10 mL, 5 mL, 0.1 g, 80 °C and 1 h. Agreement of 95.15–96.54 % between the measured and certified value was obtained under the optimum conditions. The spiked recovery was 103.23–103.54 %, indicating the matrix-analytes interactions were negligible. Boric acid neutralization reduced the recovery rates to 47.2–49.3 % and was not be appropriate for driving HF. The optimal spectral line for determining Ge is at a wavelength of 265.117 nm, at which the limit of detect and the limit of quantification were 0.46 μg L−1 and 1.53 μg L−1, respectively. The applicability of the method was validated by quantifying Ge in Ge-rich lignite, fly ashes (FA), and chlorinated distillation residue (CR) samples. The concentration of Ge in coals was 44.75–225.41 μg g−1, the content in FA was 0.68%–2.3 %, and the content in CR was 0.18 %, with the uncertainty of the method obtained being less than 0.5 %. X-ray fluorescence spectrometer (XRF) was used to verify the results. The difference between XRF data and ICP-OES data was less than 5 %, confirming the accuracy and reproductivity of the analytical method.

A new framework for soft x-ray transient gratings

The capability to use extreme ultraviolet (EUV) light for generating transient gratings (TGs) has enabled the study of thermoelastic and magnetic dynamics at the nanoscale, in thin solid samples and surfaces, without the need of specially modifying them. However, the current mirror-based setup for generating EUV TG limits both its extension to the soft x-ray photon energy range and the attainment of few femtosecond time-resolution. Here we propose to overcome these limitations with an alternative experimental scheme based on diffractive optical elements that has become feasible with the current technology. In addition, some aspects of the discussed setup may facilitate the implementation of the EUV TG approach at table-top high-harmonic generation sources.

Effect of surface topography on the fatigue behavior of additively manufactured Ti6Al4V and CoCr alloys

Powder bed fusion (PBF), including selective laser melting and electron beam melting, fabricates complex, porous, osseointegrative implants for widespread clinical use. Fatigue testing is imperative for predicting long-term strength and durability of rough and surface porous implants while bone remodels around and grows into the implant. This study analyzes different materials (Ti6Al4V and Co28Cr6Mo) with varying topographies including as-printed surface roughness and the addition of a surface porous layer common to implants. The results are compared to wrought and PBF controls that are polished and machined. Moreover, different PBF techniques for titanium result in different as-printed surface roughness (∼0.07–17 μm) and microstructure. The fatigue data demonstrates that the surface finish impact was stronger in Ti6Al4V versus CoCr and SLM Ti6Al4V HIP + surface porous gyroid samples didn't perform worse than the roughest solid sample without surface porosity (EBM Ti6Al4V). With the same mechanical surface finishes, the SLM and wrought Ti6Al4V samples display similar fatigue resistance (800 and 850 MPa respectively), while EBM samples remain inferior (350 MPa). This study provides a foundation to compare fatigue resistance across materials and surface topographies through different fabrication techniques to optimize the lifespan of orthopedic implants while incorporating rough as printed surfaces and added surface porosity, both of which are essential for osseointegration.

Isolation of the contribution of viscous flow to initiation of pentaerythritol tetranitrate during sub-shock impact

The drop weight impact experiment is used routinely to provide an initial screening of the handling sensitivity of new explosives. Despite the ubiquity and simplicity of the drop weight impact test, the physical mechanisms responsible for generating temperatures sufficiently high for the initiation of explosive reactions are not well understood. Preliminary work has shown that temperatures sufficient for ignition are in theory achievable in steady-state Poiseuille flow at the flow velocities observed experimentally with temperature-dependent shear viscosities. However, it is far from certain that such steady-state flow conditions can be achieved in the drop weight impact test because of its short duration. Therefore, here we study heat generation both experimentally and numerically to quantify the temperature distributions in molten pentaerythritol tetranitrate (PETN). Drop weight experiments have been performed starting with PETN that has been melted on a transparent anvil. The experimental results are consistent with our finite element calculations that indicate that the temperature does not approach the level needed for ignition on the time scales of the experiment. Interestingly, ignition regularly occurs in solid samples under the same conditions, so we discuss the phenomenology of ignition of both solid and molten PETN in the drop weight test and provide constraints to numerical simulations.

Rapid and simultaneous detection of cadmium and mercury in foods based on solid sampling integrated electrothermal vaporization technique

This work presents an innovative solid sampling (SS) integrated electrothermal vaporization (ETV) approach for simultaneous determination of Cd and Hg based on differentiated elemental vaporization and transportation behavior characteristics. A miniature N2/H2 generator, only consuming electricity and H2O, was utilized to yield reducing atmosphere for Cd vaporization; MgO filler was modified to absorb matrix interferent and keep Hg and Cd transportation via 1st catalytic pyrolysis furnace (CPF); and a gearing was employed to move 2nd CPF to receive and trap (amalgamation) the vaporized Hg from ETV and then thermo-release them for simultaneous detection. Under optimized conditions, the limits of detection of Cd and Hg reached 0.02–0.04 ng/g using 0.4 g sample size. The linearities (R2) exceeded 0.998 and recoveries were 85.0–111.9%, indicating favorable analysis precision and accuracy within ∼3 min without sample digestion process. The proposed HgCd analyzer is suitable for rapid monitoring food with simplicity, green and safety.