Homogeneous Sample Research Articles

Search for giant planets in M 67 V: A warm Jupiter orbiting the turn-off star S1429

Context. Planets orbiting members of open or globular clusters offer a great opportunity to study exoplanet populations systematically, as stars within clusters provide a mostly homogeneous sample, at least in chemical composition and stellar age. However, even though there have been coordinated efforts to search for exoplanets in stellar clusters, only a small number of planets have been detected. One successful example is the seven-year radial velocity (RV) survey ‘Search for giant planets in M 67’ of 88 stars in the open cluster M 67, which led to the discovery of five giant planets, including three close-in (P < 10 days) hot-Jupiters. Aims. In this work, we continue and extend the observation of stars in M 67, with the aim being to search for additional planets. Methods. We conducted spectroscopic observations with the Habitable Planet Finder (HPF), HARPS, HARPS-North, and SOPHIE spectrographs of 11 stars in M 67. Six of our targets showed a variation or long-term trends in their RV during the original survey, while the other five were not observed in the original sample, bringing the total number of stars to 93. Results. An analysis of the RVs reveals one additional planet around the turn-off point star S1429 and provides solutions for the orbits of stellar companions around S2207 and YBP2018. S1429 b is a warm-Jupiter on a likely circular orbit with a period of $\[\77.48_{-0.19}^{+0.18}\]$ days and a minimum mass of M sin i = 1.80 ± 0.2 MJ. We update the hot-Jupiter occurrence rate in M 67 to include the five new stars, deriving $\[\4.2_{-2.3}^{+4.1} \%\]$ when considering all stars, and $\[\5.4_{-3.0}^{+5.1} \%\]$ if binary star systems are removed.

A quality‐related distributed process monitoring framework for large‐scale manufacturing processes with multirate sampling measurements

SummaryQuality‐related process monitoring has become a research hot‐spot in the field of industrial control because it is essential to ensure the process safety and product quality. A great number of data driven quality‐related process monitoring methods have been developed for large‐scale manufacturing processes, and most of them are developed based on homogeneous sampling measurement. Therefore, it is necessary to develop quality‐related monitoring methods for large‐scale processes with multirate sampling measurements. In this paper, a new quality‐related distributed monitoring framework for large‐scale manufacturing processes with multirate sampling measurements is proposed. First, a new subsystem decomposition method for multirate sampling processes combining prior knowledge and mutual information is proposed by introducing mathematic expectations. Second, local monitoring model is designed for each subsystem. Multirate partial least squares regression is adopted for modeling among the process and quality variables. The monitoring metrics of the isolation‐based anomaly detection using nearest‐neighbor ensembles are built in prediction space and process space, respectively. Finally, Bayesian inference is introduced to obtain statistical indicators for the plant‐wide processes. The validity of the proposed framework is verified in Tennessee Eastman process and a real hot strip mill process. The results show that the proposed method has favorable effectiveness and significant performance gains compared with state‐of‐the‐art methods.

Qualitative Analysis of the Lived Experience of Reproductive and Pediatric Health Care in the Military Health Care System.

Persistent inequities exist in obstetric and neonatal outcomes in military families despite universal health care coverage. Though the exact underlying cause has not been identified, social determinants of health may uniquely impact military families. The purpose of this study was to qualitatively investigate the potential impact of social determinants of health and the lived experiences of military individuals seeking maternity care in the Military Health System. This was an Institutional Review Board-approved protocol. Nine providers conducted 31 semi-structured interviews with individuals who delivered within the last 5 years in the direct or purchased care market. Participants were recruited through social media blasts and clinic flyers with both maximum variation and homogenous sampling to ensure participation of diverse individuals. Data were coded and themes were identified using inductive qualitative research methods. Three main themes were identified: Requirements of Military Life (with subthemes of pregnancy notification and privacy during care, role of pregnancy instructions and policies, and role of command support), Sociocultural Aspects of the Military Experience (with subthemes of pregnancy as a burden on colleagues and a career detractor, postpartum adjustment, balancing personal and professional requirements, pregnancy timing and parenting challenges, and importance of friendship and camaraderie in pregnancy), and Navigating the Healthcare Experience (including subthemes of transfer between military and civilian care and TRICARE challenges, perception of military care as inferior to civilian, and remote duty stations and international care). The unique stressors of military life act synergistically with the existing health care challenges, presenting opportunities for improvements in care. Such opportunities may include increased consistency of policies across services and commands. Increased access to group prenatal care and support groups, and increased assistance with navigating the health care system to improve care transitions were frequently requested changes by participants.

Comparative Study of Collagen Density, Fibroblast, and Neovascularization in Tracheal Defect Reconstruction with Primary Repair and External Oblique Muscle Aponeurosis Patch (A Novel Study with New Zealand Rabbit)

Background: The lack of ideal materials and the high incidence of complications make tracheal defect reconstruction challenging. The use of aponeurosis as a surgical patch and flap in reconstruction is not uncommon, but no studies had been conducted to analyse its use in tracheal defect reconstruction, though its effectivity in wound healing was significant in reconstruction of other organs. Objective: This study aims to compare collagen density, fibroblast expression, and neovascularization in tracheal defect reconstruction using primary suture and using external oblique muscle aponeurosis patch. Methods: This randomized control trial is a laboratory experimental study using male New Zealand white rabbits. Randomization was carried out with permuted block randomization into a control group (primary suture) and a treatment group (reconstruction with external oblique muscle aponeurosis patch). Mascroscopic and histopathological assessments were carried out 14 days after surgery. Results: We got homogeneous samples in both groups (9 samples each) in terms of age (p = 0.763), weight before procedure (p = 0.347), and weight after procedure (p = 0.536). Macroscopically, no wound dehiscence, pus, or inflammation at the surgical site in either the control or treatment groups. Histopathological analysis showed that there were no differences in collagen density (p = 1.00), fibroblast expression (p = 0.414), and neovascularization (p = 0.558) between the two groups. Conclusion: It can be concluded that there are no differences in collagen density, fibroblast expression, and neovascularization in New Zealand rabbits with tracheal defect using primary suture and using external oblique muscle aponeurosis patch

Significantly Enhanced Thermal Conductivity of hBN/PTFE Composites: A Comprehensive Study of Filler Size and Dispersion.

High-temperature polymers are attractive for applications in extreme temperatures, where they maintain their mechanical flexibility and electrical insulating properties. However, their heat dissipation capability is limited due to their intrinsically low thermal conductivities. Hexagonal boron nitride (hBN) is a chemically inert, thermally stable, and electrically insulative compound with a high thermal conductivity, making it an ideal candidate as a filler within a high-temperature polymer matrix to increase the thermal conductivity. This study evaluates the effect of filler size and dispersion on thermal conductivity by producing homogeneous composite samples using a combination of solvent mixing and resonant acoustic mixing (RAM). We carefully characterized our samples, including the spread of the size distribution, and observed that the smaller sized hBN centered around 5 μm was able to integrate more seamlessly into the polytetrafluoroethylene (PTFE) matrix with particle size in the 15 μm range and hence outperformed 30 μm, in contrast to the conventional wisdom, which asserts that larger fillers universally perform better than smaller ones. Our thermal conductivity of hBN/PTFE composites at 30 wt % is 2× higher than the literature values. Notably, we reached the record-high value of 3.5 W/m K at 40 wt % with an onset of percolation at 20 wt %, attributed to optimized hBN dispersion that facilitates the formation of thermal percolation. Our findings provide general guidelines to enhance the thermal conductivity of polymer composites for thermal management, ranging from power transmission to microelectronics cooling.

Vitamin C Levels in Pregnant Women and the Efficacy of Vitamin C Supplements in Preventing Premature Rupture of Membranes: A Systematic Review and Meta-Analysis.

Premature rupture of membranes (PROM) is defined as the leakage of amniotic fluid before the onset of labor and delivery contractions. Some studies found that women who experienced PROM had significantly lower vitamin C blood levels than those who did not, while others found no significant differences. Previous systematic reviews and meta-analyses on the efficacy of vitamin C in the prevention of PROM had conflicting results. We aimed to conduct a systematic review and meta-analysis to determine if there was a significant difference in vitamin C blood levels in women who had PROM versus the control group who did not and to determine if vitamin C supplements could help prevent it. Systematic review and meta-analysis. We registered our protocol with PROSPERO (CRD42022371644). We searched PubMed/MEDLINE, Web of Science, and Scopus through February 15, 2024. Additionally, backward and forward citation searches were conducted. Studies were selected based on predetermined inclusion and exclusion criteria. Meta-Essentials: Workbooks for Meta-Analysis (Version 1.5) was used for analysis. Twenty-five studies (26 reports) met all eligibility criteria, with 18 studies (18 reports) assessing vitamin C levels and seven studies (eight reports) evaluating efficacy. Women with PROM, whether preterm or term, had significantly lower vitamin C levels [Hedges' g, -1.48; 95% confidence interval (CI): -2.82, -0.14; p = 0.020; I2 = 94.08%) and specifically preterm PROM after removing the outlying study [Hedges' g, -1.29; 95% CI: -1.85, -0.73; p < 0.001; I2 = 87.35%). Vitamin C supplementation significantly reduced the risk of preterm or term PROM [risk ratio (RR), 0.57; 95% CI: 0.39, 0.81; p < 0.001; I2 = 12.17%), particularly for preterm PROM (RR, 0.67; 95% CI: 0.45, 0.99; p = 0.001; I2 = 0.00%). There were no significant differences in vitamin C levels between women with term PROM and controls, and there were no differences in the risk of developing term PROM between women taking vitamin C supplements and controls. Results were not robust in all sensitivity analyses. Women with PROM, particularly those who developed it preterm, appear to have significantly lower vitamin C levels, and vitamin C supplementation appears to be effective in reducing the risk of PROM, particularly preterm PROM. More high-quality studies with low risk of bias, more homogenous, and larger samples are needed to confirm these findings.

A Sensitive Liquid Chromatography-Tandem Mass Spectrometry Method for Measuring Fosfomycin Concentrations in Human Prostatic Tissue.

The aim of this study was to develop and validate a fast and sensitive bioanalytical method for the accurate quantification of fosfomycin concentrations in human prostatic tissue. The sample preparation method only required milligrams of tissue sample. Each sample was mixed with two times its weight of water and homogenized. A methanol solution that was three times the volume of the internal standard (fosfomycin-13C3) was added, followed by vortex mixing and centrifugation. After its extraction from the homogenized prostatic tissue, fosfomycin was quantified by means of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) triple quadrupole system operating in negative electrospray ionization and multiple reaction monitoring detection mode. The analytical procedure was successfully validated in terms of specificity, sensitivity, linearity, precision, accuracy, matrix effect, extraction recovery, limit of quantification, and stability, according to EMA guidelines. The validation results, relative to three QC levels, were 9.9% for both the within-day and inter-day accuracy (BIAS%); 9.8% for within-day precision; and 9.9 for between-day precision. A marked matrix effect was observed in the measurements but was corrected by normalization with the internal standard. The average total recovery was high (approximatively 97% at the three control levels). The dynamic range of the method was 0.1-20 μg/g (R2 of 0.999). Negligible carry-over was observed after the injection of highly concentrated samples. F in the sample homogenate extracts was stable at 10 °C and 4 °C for at least 24 h. In the tissue sample freeze-thaw experiments, a significant decrease in F concentrations was observed after only two cycles from -80 °C to room temperature. The novel method was successfully applied to measure fosfomycin in prostatic tissue samples collected from 105 patients undergoing prostatectomy.

In situ investigation on the evolution mechanism of heterogeneous micro-scale structure in potassium-niobate microwave flash sintering

Heterogeneity in the final product of flash sintering is a significant limitation for massive development. Synchrotron radiation computed tomography (SR-CT) was initially used to investigate the in-situ experiment of potassium-niobate (KNbO3) prepared by microwave flash sintering, revealing the temporal evolution of KNbO3 microstructure. The study has revealed the critical role of spatial arrangement between incompact particles and sintered agglomerates in achieving homogeneity in flash-sintered samples. Particles located the angle formed by the sintered agglomerate are more likely to experience electric field concentration, resulting in densification, and the densification rate decreases as the increases of angle size formed by the dense sintered agglomerates. This letter highlights that the presence of particles between sintered agglomerates is a significant factor contributing to heterogeneous sintering. The phenomenon is explained through a combination of experiments and simulation, which holds promise for enhancing the homogeneity of the sintering process.

Gender and organizational commitment: evidence from a nationwide survey in Poland

Purpose The study examines whether affective organizational commitment and its drivers differ between Polish female and male employees.Design/methodology/approach Our proprietary data are from ongoing surveys conducted by a major Polish HR consulting firm. The nationwide survey of nearly 3,000 Polish workers in 2020 constitutes the data set in this analysis. Regression analysis is applied to analyze the relationship between organizational commitment, gender and other variables.Findings The study provides support for the job model, that is, women and men have similar levels of commitment once all other factors are controlled. Although the results show that, ceteris paribus, the organizational commitment of women is statistically significantly higher than that of men, the effect size is trivial in practical terms. The study also discloses the fact that the determinants of organizational commitment of men and women are similar, thus refuting a commonly held notion about gendered job attribute preferences. Support for gender as a moderator between organizational commitment and its antecedents is not found. COVID-19-related work adjustments do not seem to have affected the commitment of Polish male and female workers to their employers.Originality/value The study adds to the scarce empirical literature on organizational commitment in Poland. To date, only a small number of such studies exist for Poland, and all of them use small homogeneous samples and limited questionnaires. The results are of value to researchers as well as HR managers seeking to improve long-term commitment to organizations.

Challenges of implementing a climate-smart agriculture-based curriculum in agricultural vocational schools: evidence from Iran

The research aimed to identify the challenges of developing and implementing a climate-smart agriculture (CSA)-based curriculum in Iran’s agricultural vocational schools. It was exploratory descriptive-analytical in nature and applied in goal, in which data were collected with the library and deep interview method. The research methodology was based on grounded theory. The statistical population was composed of 16 researchers, authors, managers, and experts of the Office of Textbook Compilation of the Organization for Educational Research and Planning and the Research Center of Educational Studies. The participants were selected by the homogenous purposive sampling method. The interview with the target population continued until it reached theoretical saturation. Data were analyzed using the content analysis method. The data collected in the interviews were subjected to open, axial, and selective coding, which resulted in deriving 119 concepts and 28 categories. The results revealed a seven-dimension structure composed of the challenges related to determining educational goals, trainees, trainers’ professional process, teaching methods, curriculum content selection and organization, curriculum implementation, and curriculum appraisal. The results can help the experts in the Office of Textbook Compilation experts adopt smarter policies and solutions to solve the challenges of developing and implementing a CSA-based curriculum in agricultural vocational schools in Iran.

Nucleus pulposus structure and function assessed in shear using magnetic resonance elastography, quantitative MRI, and rheometry.

In vivo quantification of the structure-function relationship of the intervertebral disc (IVD) via quantitative MRI has the potential to aid objective stratification of disease and evaluation of restorative therapies. Magnetic resonance elastography (MRE) is an imaging technique that assesses tissue shear properties and combined with quantitative MRI metrics reflective of composition can inform structure-function of the IVD. The objectives of this study were to (1) compare MRE- and rheometry-derived shear modulus in agarose gels and nucleus pulposus (NP) tissue and (2) correlate MRE and rheological measures of NP tissue with composition and quantitative MRI. MRE and MRI assessment (i.e., T1ρ and T2 mapping) of agarose samples (2%, 3%, and 4% (w/v); n = 3-4/%) and of bovine caudal IVDs after equilibrium dialysis in 5% or 25% PEG (n = 13/PEG%) was conducted. Subsequently, agarose and NP tissue underwent torsional mechanical testing consisting of a frequency sweep from 1 to 100 Hz at a rotational strain of 0.05%. NP tissue was additionally evaluated under creep and stress relaxation conditions. Linear mixed-effects models and univariate regression analyses evaluated the effects of testing method, %agarose or %PEG, and frequency, as well as correlations between parameters. MRE- and rheometry-derived shear moduli were greater at 100 Hz than at 80 Hz in all agarose and NP tissue samples. Additionally, all samples with lower water content had higher complex shear moduli. There was a significant correlation between MRE- and rheometry-derived modulus values for homogenous agarose samples. T1ρ and T2 relaxation times for agarose and tissue were negatively correlated with complex shear modulus derived from both techniques. For NP tissue, shear modulus was positively correlated with GAG/wet-weight and negatively correlated with %water content. This work demonstrates that MRE can assess hydration-induced changes in IVD shear properties and further highlights the structure-function relationship between composition and shear mechanical behaviors of NP tissue.

Speed of sound measurement and mapping in transparent materials by impulsive stimulated Brillouin microscopy

Impulsive stimulated Brillouin scattering (ISBS) is a variant of stimulated Brillouin scattering, which can overcome the shortcomings of the long acquisition time of traditional Brillouin microscopy. We introduce the difference between ISBS and other Brillouin microscopies in calculating longitudinal modulus. The Brillouin frequency shift obtained by ISBS is only related to the system parameters and the speed of sound (SOS) in the sample, not to the refractive index. Non-contact SOS measurement of homogeneous samples is an important application of Brillouin scattering, used in the early study of Brillouin spectroscopy and the mechanical properties of liquids. However, the measurement requires prior knowledge of the sample refractive index, which limits the measurement of the unknown refractive index sample. Here, we propose a method to measure the SOS based on ISBS, which in principle avoids the need for refractive index parameters. The SOS of several liquids are measured and compared with the standard values. The mean relative standard deviation is 1.13%. Moreover, we measure the SOS of a mixture of ethanol and water to demonstrate an application of measuring SOS without refractive index information. We also demonstrate the high spatial resolution of ISBS with a methanol-filled PDMS sample.

Contrast between Brazil and other countries in nutraceutical components of Camelina sativa grains

Camelina sativa, also known as false flax, is a species can be cultivated in a variety of climates, seasons and soil types, due to its short development cycle and tolerance to drought and low temperatures. In the composition of its grains, it presents a high amount of oil and rich in unsaturated fatty acids. In view of this, the objective of this work was to compare the composition of the nutraceutical components of Camelina sativa L. grains cultivated in Brazil and countries in Europe, Asia and North America. About 20 kg of grains were collected and then a homogeneous sample of 1kg of grains was cleaned to perform the centesimal composition of the grains. Afterwards, a search for information was carried out on the cultivation of Camelina sativa L. in other countries and the collection of information on the centesimal composition of the grains of this oleaginous plant. The collection of information was based on obtaining published scientific articles on the nutraceutical composition of Camelina sativa in regions of Europe, Asia and North America. Brazil presents a promising environment for the cultivation of Camelina sativa, with superior performance for the content of stearic acid, linoleic acid, linolenic acid and palmitic acid. The fatty acids profile decreased with the reduction of the minimum air temperature. The mineral material, palmitic acid and linolenic acid are positively correlated.

Dosimetric characteristics of 3D-printed and epoxy-based materials for particle therapy phantoms

Objective3D printing has seen use in many fields of imaging and radiation oncology, but applications in (anthropomorphic) phantoms, especially for particle therapy, are still lacking. The aim of this work was to characterize various available 3D printing methods and epoxy-based materials with the specific goal of identifying suitable tissue surrogates for dosimetry applications in particle therapy.Methods3D-printed and epoxy-based mixtures of varying ratios combining epoxy resin, bone meal, and polyethylene powder were scanned in a single-energy computed tomography (CT), a dual-energy CT, and a µCT scanner. Their CT-predicted attenuation was compared to measurements in a 148.2 MeV proton and 284.7 MeV/u carbon ion beam. The sample homogeneity was evaluated in the respective CT images and in the carbon beam, additionally via widening of the Bragg peak. To assess long-term stability attenuation, size and weight measurements were repeated after 6–12 months.ResultsFour 3D-printed materials, acrylonitrile butadiene styrene polylactic acid, fused deposition modeling printed nylon, and selective laser sintering printed nylon, and various ratios of epoxy-based mixtures were found to be suitable tissue surrogates. The materials’ predicted stopping power ratio matched the measured stopping power ratio within 3% for all investigated CT machines and protocols, except for µCT scans employing cone beam CT technology. The heterogeneity of the suitable surrogate samples was adequate, with a maximum Bragg peak width increase of 11.5 ± 2.5%. The repeat measurements showed no signs of degradation after 6–12 months.ConclusionWe identified surrogates for soft tissue and low- to medium-density bone among the investigated materials. This allows low-cost, adaptable phantoms to be built for quality assurance and end-to-end tests for particle therapy.

Soil contribution to the cobalamin (vitamin B12) supply of terrestrial organisms

AbstractCobalamin (Vitamin B12) is a cofactor for many enzymes, including those in bacteria, archaea, algae, and mammals. In humans, cobalamin deficiency can lead to pernicious anaemia as well as gastrointestinal and neurological disorders. In contrast to marine ecosystems, there is a great paucity of information on the role of soils and terrestrial plants in the supply of cobalt and cobalamin to microorganisms and animals. The content of cobalt cations in most soils is usually sufficient to maintain growth, and the density of cobalamin-producing soil prokaryotes is high in comparison to water bodies. The cobalt content of most soils is usually sufficient in comparison with water, and the density of cobalamin-producing soil prokaryotes is high. Therefore, terrestrial plants are an important cobalt source for cobalamin-producing rumen and gut prokaryotes. The major source of cobalamin for most other animals is the meat of ruminants as well as other animal-derived products, bacteria in insects, and coprophagy, e.g., by rodents. In addition, faecal deposits, and fertilizers as well as soil bacteria add to the cobalamin supply. However, those archaea and bacteria that do not produce cobalamin obtain this coenzyme or its analogues from the environment. Therefore, presence or absence of cobalamin-producing species in soil affects the whole soil microbiome. However, our knowledge concerning microbial producers and consumers of cobalamin in soils is still limited, despite some recent advances. The main reasons are a low cobalamin content in soils and challenging methods of determination. In this regard, advanced analytical knowledge and technical equipment are required, which are usually unavailable in soil laboratories. This review provides relevant methodological information on sample homogenization, extraction, concentration, and purification as well as analysis of cobalamin.

High-harmonic spin-shearing interferometry for spatially resolved EUV magneto-optical spectroscopy

We present a method for achieving hyperspectral magnetic imaging in the extreme ultraviolet (EUV) region based on high-harmonic generation (HHG). By interfering two mutually coherent orthogonally-polarized and laterally-sheared HHG sources, we create an EUV illumination beam with spatially-dependent ellipticity. By placing a magnetic sample in the beamline and sweeping the relative time delay between the two sources, we record a spatially resolved interferogram that is sensitive to the EUV magnetic circular dichroism of the sample. This image contains the spatially-resolved magneto-optical response of the sample at each harmonic order, and can be used to measure the magnetic properties of spatially inhomogeneous magnetic samples.

The Chinese version of the general benefit finding scale (GBFS): Psychometric properties in a sample of college students.

Benefit finding has become a central construct in the evolution of positive psychology and attracted attention in recent literature. This study aimed to translate and validate the General Benefit Finding Scale (GBFS) in Chinese college students. Forward- and back-translation of the GBFS was followed by the assessment of semantic equivalence and content validity. A sample of 589 college students was recruited in China to conduct reliability and validity analysis. The construct validity was assessed using exploratory (EFA) and confirmatory factor analysis (CFA). Concurrent validity was assessed using Pearson's correlation coefficients of the GBFS with the Perceived Stress Scale (PSS) and World Health Organization-Five Well-Being (WHO-5). Internal consistency and two-week test-retest reliability were also evaluated. The content validity index for each item ranged from 0.83 to 1.00. EFA revealed a six-factor model, which exhibited acceptable goodness of fit in CFA (standardized root mean square residual = 0.031, root mean square error of approximation = 0.059, goodness-of-fit index = 0.860, comparative fit index = 0.904, Tucker-Lewis index = 0.890, chi-squared/degree of freedom = 2.07). The concurrent validity of the GBFS was supported by its statistically significant correlations with PSS (r = -0.271, p<0.001) and WHO-5 (r = 0.354, p<0.001). Moreover, the internal consistency for the overall scale was satisfactory, with Cronbach's α coefficient of 0.93 and McDonald's omega reliability of 0.94. The test-retest reliability was 0.82. Although the Chinese version of GBFS was examined in a homogeneous convenience sample of college students, it provides a reliable and valid instrument for assessing benefit finding in the Chinese context.

A green and facile direct ink writing technique for preparation calibration standards in laser ablation inductively coupled plasma mass spectrometry analysis

BackgroundLaser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful tool for microanalysis of solid materials. Nevertheless, one limitation of the method is the lack of well-characterized homogeneous reference materials (RMs), such as BaF2 crystal and BaCO3 ceramics samples, making direct quantification difficult. This work presents a novel Direct Ink Writing (DIW) method to produce RMs for microanalysis. The Mg, Cr, Fe, Co, Ni, Cu, Y, Mo, Pr, Gd, Dy, Ho, Er, Tm, Yb, and Lu solutions were gravimetrically doped into BaCO3 by mixing with the dispersant and then cured with DIW techniques. (94) ResultsBaCO3 powder was combined with a dopant analyte to produce a printable slurry, aided by the use of a dispersant and cellulose. The resulting mixture was then printed using DIW equipment. The retention rates of the doped elements were investigated by internal and external standard method, and the results showed that they were completely dispersed in the solid material. After further optimization, it was found that there was no significant heterogeneity among the printed samples. LA-ICP-MS was used to analyze printed samples, to evaluate micro-scale homogeneity. The mass concentration of the doped element was determined by ICP-MS, verify its move closer to nominal value. Compared with the traditional reference materials preparation methods, the DIW technology greatly increased the sample homogeneity and the accuracy of the desired concentration. (132) SignificanceAs far as we know, there are few reports on the application of DIW method to prepare calibration standards. In brief, it is proved that the proposed method of preparing calibration standard by DIW technique to quantify analytes is valid and robust. This procedure provides great potential for LA-ICP-MS in-situ analysis in the field of well-prepared products, such as ceramic and crystal samples.(63)

Non-destructive characterization of silicon nanowires and nanowire coatings using mid-infrared spectroscopy

Silicon nanowires (SiNWs) have attracted much attention owing to their potential applications in electronics and photonics, while remaining as a cost-effective material platform. Key material properties in engineering SiNWs for different applications include their length, density, and presence of oxides or other chemicals on the surface. However, monitoring these properties is challenging, as scanning electron microscopy and atomic force microscopy (AFM), which directly image the wires, require destructive cleaving of the sample. This paper uses polarized, variable-angle Fourier Transform IR reflectance spectroscopy as a nondestructive technique to characterize the areal density and length of metal-assisted chemically etched SiNW arrays. In addition to the ability to characterize “as-etched” wires, we show that IR spectroscopy can also measure few-nanometer thick layers of aluminum oxide (AlOx) grown radially around the length of the SiNWs utilizing atomic layer deposition. Despite sample inhomogeneities, an effective medium theory (EMT) model can determine the length and density of the NWs for a range of lengths between 3 and 14 μm. The EMT can also reproduce the experimentally measured vibrational bands for coated NWs, demonstrating that IR spectroscopy can also evaluate the presence of molecular contaminants on the wires.

How long can you store vitamins? Stability of tocopherols and tocotrienol during different storage conditions in broccoli and blueberries

Differences between the stability of α-, β-, γ-, and δ-tocopherol as well α-tocotrienol stored at −20 °C and −80 °C were studied in broccoli and blueberry samples. Before storage up to 28 days, they underwent different initializing processes such as freezing quickly with liquid nitrogen and freeze-drying, followed by homogenization. While α-tocopherol levels in blueberries did not significantly differ, levels in broccoli were substantially higher after homogenization of freeze-dried samples compared to fresh broccoli samples. This might be caused by higher extractability of α-tocopherol from the changed cell structure. Storage of fresh broccoli samples at −20 °C led to decreasing α-tocopherol levels. Nevertheless, the deviation between freeze-dried samples to the initial fresh samples and fresh samples frozen with liquid nitrogen stored at −20 °C for 7 days were in the same order of magnitude. In conclusion, storage up to 7 days for vitamin relevant samples before analysis seemed to be justifiable.