Sample Volume Research Articles

Behavioral risk assessment of work-related musculoskeletal disorders among workers of petrochemical industries: protocol of a mixed method study

BackgroundMusculoskeletal disorders (MSDs) are one of the most common occupational diseases and the main cause of disability worldwide. Work-related musculoskeletal disorders (WMSDs) are one of the common health risks and the most important cause of absenteeism due to disability in various industries, including the petrochemical industry, in developed and developing countries. These disorders have important social economic, and significant financial consequences due to direct and hidden costs. Health behaviors play a role in both creating and preventing musculoskeletal disorders in employees. Therefore, by identifying the influencing factors on these behaviors, it is possible to strengthen and improve the preventive behaviors of musculoskeletal disorders through educational intervention programs. This study aims to assess the behavioral risk of work-related musculoskeletal disorders, and design and implement an educational intervention to teach effective behaviors in the prevention of musculoskeletal disorders in petrochemical industry workers.MethodsThis study is a mixed-method study implemented in four stages involving the qualitative study, the design and evaluation of an instrument, the design of an experimental randomized clinical trial, and the psychometric evaluation of the instrument and the evaluation of the program. The research community consists of employees working in the petrochemical industry. The volume of samples in the qualitative study with the purposeful sampling method, in the instrument design stage based on the available sampling method, and also in the experimental study, the samples are employees suffering from work-related musculoskeletal disorders, who were selected based on a simple random method from among the employees of the petrochemical industry. Then they will be divided into intervention and control groups. The instruments of this research include a demographic questionnaire, a researcher-made questionnaire for measuring behavior, and two auxiliary instruments including the visual analog scale (VAS) and the Quebec Disability Scale. Evaluation is done in 4 stages: pre-test, immediately, 3, and 6 months after the intervention of both groups. The obtained data will be analyzed using SPSS software.DiscussionMusculoskeletal disorders related (WMSDs) to work can harm employees’ health in various industries, including the petrochemical industry. This study attempts to evaluate the behavioral risk of work-related musculoskeletal disorders among petrochemical industry workers and design and implement an appropriate educational intervention program.Trial registrationIranian Registry of Clinical Trial (IRCT20240321061346N1). Registered on 2024–04-10.Ethics Status: Ethics code: IR.MODARES.REC.1402.251.

Novel Simple Approach for Production of Elastic Poly(propylene carbonate)

The simple approach of increasing the elastic properties of atactic poly(propylene carbonate) (PPC) with Mn = 71.4 kDa, ĐM = Mw/Mn = 1.86, and predominantly carbonate units (>99%) is suggested by selecting the appropriate hot pressing temperature for PPC between 110 and 140 °C. Atactic PPC is synthesized through ring-opening copolymerization of (rac)-propylene oxide and CO2 mediated by racemic salen complex of Co(III). Hot pressing PPC results in the release of a small amount of propylene carbonate (PC), sufficient to lower the glass transition temperature from 39.4 to 26.1 °C. Consequently, increasing the pressing temperature from 110 to 140 °C generates materials with a reduced modulus of elasticity (from 1.94 to 0.09 GPa), yield strength (from 38 to 2 MPa) and increased tensile elongation (from 140 to 940%). Thermomechanical analysis has shown a significant expansion in sample volume by hundreds of percent within the 80–130 °C range. PPC also displays large, reversible deformations, which can be utilized by creating shape memory materials.

Benchmarking of a multi-biomarker low-volume panel for Alzheimer's disease and related dementia research.

In the research setting, obtaining accurate established biomarker measurements and maximizing use of the precious samples is key. Accurate technologies are available for Alzheimer's disease (AD), but no platform can measure all the established and emerging biomarkers in one run. The NUcleic acid Linked Immuno-Sandwich Assay (NULISA) is a technology that requires 15µL of sample to measure more than 100 analytes. We compared AD-relevant biomarkers included in the NULISA against validated assays in cerebrospinal fluid (CSF) and plasma. CSF measures of amyloid beta 42/40, and phosphorylated tau (p-tau)217 are highly correlated when measured by immunoassay, mass spectrometry, or NULISA. In plasma, p-tau217 performance is similar to that reported with other technologies when predicting amyloidosis. Other biomarkers show a wide range of correlation values depending on the fluid and the platform. The NULISA multiplexed platform produces reliable results for established biomarkers in CSF that are useful in research settings, with the advantage of measuring additional biomarkers using minimal sample volume. We tested the novel technology NUcleic acid Linked Immuno-Sandwich Assay (NULISA) in the dementia research setting. NULISA multiplexed platform produces reliable results for established and emerging biomarkers using minimal sample volume. Cerebrospinal fluid measures of amyloid beta 42/40, and phosphorylated tau (p-tau)217 are highly correlated when measured by immunoassay, mass spectrometry, or NULISA. In plasma, p-tau217 performance is similar to that reported with other technologies when predicting amyloidosis. NULISA measures are useful in research settings, with the advantage of measuring additional biomarkers using minimal sample volume.

Integrated dual-biomarker detection: Transforming proteins and nucleic acids into ssDNA for enhanced disease diagnosis

Integrating information from protein and nucleic acid biomarkers enhances detection sensitivity and specificity, offering valuable insights for disease management compared to single biomarkers alone. Thus, there is an increasing demand for a unified diagnostic approach by introducing an innovative assay that simultaneously detects protein and nucleic acid biomarkers within a single test. Here we developed a method that uniquely transforms both protein and nucleic acid markers into single-stranded DNAs (ssDNAs), utilizing a novel combination of aptamers and the CRISPR/Cas9 system. Subsequent amplification of these ssDNAs through both linear and exponential rolling circle amplification enables simultaneous and efficient detection. This approach not only simplifies the diagnostic process but also conserves valuable sample volume, reduces the time required for detection, and minimizes the consumption of reagents and the need for extensive instrumentation. In a critical proof-of-concept application, we employed this assay to detect programmed cell death-ligand 1 (PD-L1) protein and epidermal growth factor receptor (EGFR) L858R circulating tumor DNA (ctDNA) in plasma of patients with non-small cell lung cancer (NSCLC), which helps to guide the selection of the most appropriate treatment for NSCLC patients, whether immunotherapy (based on PD-L1 expression) or targeted therapy (based on EGFR mutation). The remarkable results demonstrated high sensitivity (83.3% for EGFR L858R ctDNA and 88.2% for PD-L1) and specificity (100% for EGFR L858R ctDNA and 87.5% for PD-L1). These findings not only validate the effectiveness of our method but also underscore its potential as a transformative tool in the simultaneous monitoring of multiple types of biomarkers, paving the way for more nuanced and effective disease management strategies.

Repetitive ultramicrotome trimming and SEM imaging for characterizing printed multilayer structures

Ultramicrotomy is a well-established technique that has been applied in biology and medical research to produce thin sections or a blockface of an embedded sample for microscopy. Recently, this technique has also been applied in materials science or micro- and nanotechnology as a sample preparation method for subsequent characterization. In this work, an application of ultramicrotomy for the cross-section preparation of an inkjet-printed multilayer structure is demonstrated. The investigated device is a capacitor consisting of three layers. The top and bottom electrodes are printed with silver nanoparticle ink and the dielectric layer with a ceramic nanoparticle/polymer ink. A 3D profilometer is initially used to study the surface morphology of the printed multilayer. The measurements show that both electrodes exhibit a coffee-ring effect, which results in an inhomogeneous layer structure of the device. To obtain precise 3D information on the multilayer, cross-sections must be prepared. Argon ion beam milling is the current gold standard to produce a single cross-section in good quality, however, the cross-section position within the multilayer volume is poorly defined. Moreover, the milling process requires a significant investment of time and resources. Herein, we develop an efficient method to realize repetitive cross-section preparation at well-defined positions in the multilayer volume. Repetitive cross-sections are exposed by trimming with an ultramicrotome (UM) and this blockface is subsequently transferred into a scanning electron microscope (SEM) for imaging. A combination of custom-modified UM and SEM specimen holders allows repeated transfer of the clamped multilayer sample between instruments without damage and with high positioning accuracy. This novel approach enhances the combination of an established ultramicrotome and a SEM for multilayer sample volume investigation. Thus, a comprehensive understanding of printed multilayer structures can be gained, to derive insights for optimization of device architecture and printing process.

Optimization of a disposable pipette tips extraction (DPX) for the analysis of psychoactive substances in sweat specimens using Design of Experiments.

Novel psychoactive substances (NPS) continue to emerge in the marketplace and are often found as substances in traditional illicit drug materials, and users are often unaware of the presence of other drugs. The proper identification and confirmation of the exposure to a drug is made possible when a biological specimen is collected and tested. Sweat is an alternative biological matrix of great interest for clinical, and forensic analysis. One of the reasons is attributed to its expanded drug detection window, enabling a greater monitoring capacity, and provision of information on prospective drug use. However, the concentrations of drugs in sweat samples are often low, which requires highly sensitive and selective methods. Disposable pipette tips extraction (DPX) is a new miniaturized solid phase extraction technique capable of efficiently extracting analytes from biological specimens, providing high recoveries, and requiring minimized solvent use. This study describes the development and optimization of two methods for the extraction of basic and neutral psychoactive substances from sweat samples using GC-MS and Design of Experiments (DoE). The following extraction parameters were optimized by DoE techniques: sample volume, elution solvent volume, washing solvent volume, sample aspiration time, elution solvent aspiration time, and number of cycles performed, including the elution step. It was possible to design a simple extraction protocol that provided optimized recoveries for both basic and neutral compounds. The sum of analyte areas increased at a rate of 54.7% for compounds of basic character and 39.2% for compounds of neutral character. Therefore, our results were satisfactory, demonstrating that DPX can be successfully used for extracting the target drugs from sweat samples.

Fluorescence resonance energy transfer system coupled with photonic crystals labeling strategy for multiplexed detection of microRNAs from breast cancer

MicroRNAs (miRNAs) play a crucial role in post-transcriptional gene expression and freely circulate in the body. Dysregulation of miRNA signaling is associated with various diseases, including breast cancer (BC). The miRNA profiles from liquid biopsies offer a promising strategy for cancer diagnosis, prognosis and monitoring. Particularly, the simultaneous profiling of multiple miRNA levels greatly enhances the accuracy of cancer diagnosis. In this study, photonic crystals (PhCs) serve as both labels and carriers enabling synchronous optical detection of multiple miRNA targets overexpressed in BC. The process is achieved by triggering enzyme-free amplification reactions through target interactions, generating fluorescence resonance energy transfer (FRET). The method offers high sensitivity, sequence specificity, and the capability to detect multiple targets. The limits of detection (LOD) of the sensor for miRNA-21, miRNA-155 and miRNA-10b were 6.36 fM, 8.52 fM and 6.06 fM, respectively. Moreover, the sensor can be directly applied to untreated human serum with a minimal sample volume requirement of only 1 μL. The simultaneous detection of miRNAs in clinical serum samples from healthy individuals and BC patients was carried out. The results show that the average relative expression levels of miRNA-21, miRNA-155 and miRNA-10b in the BC patient group were 12.18 ± 3.20, 17.27 ± 2.17 and 12.17 ± 1.59 times that of the healthy group, respectively. Therefore, the developed multi-detection strategy can precisely identify these cancer biomarkers and offer a crucial pathway for minimally invasive cancer diagnostics, cancer prevention, early intervention and treatment.

Diagnostic and prognostic value of time to positivity in blood cultures. An opinion paper

Time to positivity (TTP) refers to the duration required for a microbiological culture test to indicate a positive result, marking the onset of detectable bacterial or fungal growth in the sample. Numerous variables, including patient characteristics, infection source, former antimicrobial therapy, blood sample volume, and sample transportation time can influence the value of TTP. Several studies have been conducted on bloodstream infections, whereas studies on the clinical significance of yeast TTP are quite limited in the literature. Furthermore, many studies are retrospective and have a small sample size. In this opinion paper, we have formulated some questions and attempted to provide answers based on the available literature and our perspective. The objective of this opinion paper is to summarise current knowledge based on the literature, aiming to offer a critical perspective, particularly on aspects with weaker evidence, which could guide future studies in this area. We believe that TTP of blood cultures appears to exhibit considerable potential and may prove to be a valuable tool in clinical practice for estimating patient mortality risk and guiding antimicrobial therapy choices. Topics discussed include the diagnostic and prognostic role of TTP in Gram-positive and Gram-negative bacteremias and in candidemias, and the significance of differential time to positivity (DTTP). In summary, our opinion is that, based on the available literature, it is not possible to determine whether TTP provides prognostic information, particularly concerning candidemia. Therefore, clinical decisions cannot be systematically based on this parameter.

Environmentally friendly LLME-LTP of the bisphenol A from bovine milk samples

This paper developed a novel and environmental microextraction for bisphenol A from milk samples using liquid-liquid microextraction with low-temperature partitioning, which is a sample clean-up step for endocrine disruptors, being a suitable alternative. Furthermore, the microextraction and determination steps were optimized to determine and quantify the bisphenol A from milk. Thus, the determination of it was made using HPLC with fluorescence detection, obtaining the analytical with a linear range from 5.0 to 150 µg L−1 bisphenol (Area = 11,894 C (µg L−1) + 22,595) with good linearity (r = 0.9983), quantification (5.0 µg L−1) limit, and variation coefficient (4.4%), which were according to the established by regulatory agencies. The bisphenol A microextraction employed only 500 µL of the bovine milk sample and 1000 µL of acetonitrile, obtaining excellent recovery values for (89 − 105%) in UHT and pasteurized milk. This proposed methodology had several advantages in determining the bisphenol A, such as quick analysis, miniaturization of the process, decreasing the solvent and sample volume, and following the Green Analytical Chemistry.

Acoustotaxis‑based pump-less separation of highly motile human sperm by a SAW-in-capillary acoustofluidic platform

In artificial reproductive technologies mirroring in vivo fertilization, there is a correlation between sperm motility and fertilization outcomes. Here, we present a technology for separating sperm based on motility, which uses a biocompatible, pump-less, and simple acoustofluidic approach. Our developed and fabricated sperm separation configuration is an acoustofluidic platform consisting of a circular glass capillary tube mounted on top of a ZnO-based surface acoustic wave (SAW) device. It can separate highly motile sperm from small volumes of normal raw human semen samples. This configuration allows the generated traveling SAW to couple into the capillary, causing highly motile sperm cells to swim against the propagation direction of the traveling SAW along the capillary tube. We term this fascinating acoustic-induced sperm swimming behavior acoustotaxis in analogy with the well-known rheotaxis, in which sperm orientate to swim against a continuous fluid flow frequently generated by using an external pump in the microfluidic systems. Here, we benefit from the acoustotaxis for a pump-less separation of an effective highly motile sperm concentration from raw human semen samples at low volumes of up to 20–30 µL within a short period of about 4 minutes free from any centrifugation step. This sperm separation device exhibits a successful selection capability that leads to sperm progressive motility increase by 45 %, sperm curvilinear velocity by 23 %, sperm average path velocity by 69 %, and sperm linearity by 78 % in the selected cells in comparison with the raw sample. This acoustotaxic sperm selection separation approach provides an easy-to-use and effective method for the selection of highly motile sperm cells without adversely affecting sperm viability, paving the way for efficient and rapid sperm separation platforms, applicable for patients with low semen volumes, and up-scalable for a large volume of raw semen processing in a short time.

A dual-band microwave sensor for liquid permittivity characterization based on multiple complementary split-ring resonators

Abstract This article presents a dual-band planar microwave sensor to characterize the permittivity of liquid samples. The sensor utilizes a splitter–combiner microstrip segment loaded with two pairs of triangular-shaped complementary split-ring resonators (CSRRs). By integrating a meander slot into the CSRRs and incorporating inter-resonator coupling between the CSRRs, the proposed sensor achieves enhanced frequency shifts, resulting in improved sensitivity. An adulteration detection experiment is conducted to validate the sensor’s performance by mixing mineral oil into castor oil with a polydimethylsiloxane container placed on the sensing area. The variations in resonant frequency and peak attenuation are employed to extract the permittivity of the loaded liquid sample. The peak sensitivities in determining the real permittivity are measured to be 6.34% and 5.7% for the first and second frequency bands, respectively. The measured errors for extracting the real and imaginary parts of the complex permittivity are approximately 3.95% and 7.47% for the first frequency band and 3.67% and 6.28% for the second frequency band, respectively. The proposed dual-band microwave sensor, with its high sensitivity, compact size, small sample volume, and low cost, demonstrates great potential for applications in the quality monitoring of agricultural and industrial products.

Cement Board Using Discarded Peanut Shell (Arachis Hypogaea)

This study investigates the use of powdered peanut shells as a sustainable alternative in cement board production. With the growing emphasis on eco-friendly construction materials, exploring alternative resources is essential. Cement boards were fabricated incorporating powdered peanut shells at varying percentages (5%, 10%, and 15% by weight) relative to the total weight of the cement mixture. The preparation involved calculating the sample volume, adjusting the mixture weight to account for the peanut shells, and setting the water-cement ratio to 0.46. The process included grinding the peanut shells, measuring all components, and thoroughly mixing them before molding. The mixtures were cured in a controlled environment to promote proper setting. The physical, mechanical, and thermal properties of the resulting boards were evaluated according to ASTM standards and analyzed using SPSS. Notably, the 5% mix achieved the highest density (1.60 g/cm³) and demonstrated excellent heat resistance, while the 15% mix exhibited the greatest thickness (1.24 cm) and lowest water absorption (10.99%). The 10% mix resulted in the highest compressive (11.28 MN/m²) and tensile strengths (0.24 N/cm²). The findings suggest that incorporating powdered peanut shells significantly improves the properties of cement boards, presenting a viable and sustainable construction option. Future studies should focus on optimizing these mixtures and assessing their long-term durability.

Repurposing eggshell membrane, a natural food waste, for in-syringe membrane solid phase extraction: Mercury determination in water samples

A rapid, simple, and cost-effective method for the determination of mercury in water samples using an eggshell membrane (ESM) as a sorbent material in the in-syringe membrane solid-phase extraction (ISMSPE) technique has been developed. The utilization of ESM, a natural waste product and a cost-effective sorbent material for ISMSPE, presents a promising approach for the determination of mercury ions, Hg(II), in water samples prior to cold vapor AAS (CV-AAS) analysis. The selectivity study of ESM shows that ESM's adsorption performance for Hg(II) is the highest among other metals, by 44.2%. The optimization for Hg(II) preconcentration, which includes the choice of eluting reagent, concentration, and volume of the eluting reagent, the number of cycles of adsorption and desorption, and sample volume, is discussed in this study. The range of linearity of this method was 0.5–100 μg/L, with a preconcentration factor of 80. This method exhibited good sensitivity, with an LOD and LOQ of 0.44 μg/L and 1.32 μg/L, respectively. The precision and accuracy of the method were also satisfactory, as indicated by the recoveries for three real water samples in the range of 89.3–99.7% and RSD% (n = 3), ranging from 1.0 to 8.0%. These findings demonstrate that the developed method is reliable and performs well in determining Hg(II) ions in real water samples. This study has successfully demonstrated ESM's potential as a valuable material for the preconcentration of Hg(II), offering an environmentally friendly approach that promotes sustainability.

Ketogenic diet and its treatment for brain and other nervous system cancers

Abstract. A growing body of empirical evidence indicates the paramount importance of nutrition in cancer treatment, especially glioma. Among the various strategies proposed to enhance traditional anticancer therapy, ketogenic diets (KD) have emerged as a noteworthy approach. In this review, seven papers highly relevant to the effects of ketogenic diet on glioma are selected and the factors involved are summarized. A Google Scholar search with the subject terms ketogenic diet and brain cancer or ketone bodies and glioma results in the selection of seven papers highly relevant to the topic. Animals injected with tumor cells or patients diagnosed with glioma, which had received a ketogenic diet for at least ten days, are included in the analysis. The metabolism-related measurements are also taken. The seven papers show that the ketogenic diet can lower glucose levels, increase -OHB levels, and reduce tumor size or weight. Additionally, it can also impact brain tumor vascularity and gene expression and potentially influence survival time, making it a promising approach for managing brain cancer in humans. In conclusion, there is evidence showing that the Ketogenic diet has the potential to treat brain cancer. Due to the duration and sample volume of the previous studies, future research still needs to continue.

Gold-coated Impedance Biosensors on PCB and PET for Real-Time Monitoring of Cancer Cells

Abstract Electrical cell-substrate impedance sensing (ECIS) biosensors are widely used for in vitro cancer cell monitoring as they are label-free, require small sample volumes, and allow real-time monitoring. ECIS electrodes are typically made of pure gold, but the usage of pure gold electrodes is too costly for single-use applications. As an alternative, this work proposes the use of gold coatings on a printed sensor's electrodes. The interdigitated electrode design was used on glass fiber-reinforced epoxy resin for printed circuit boards (PCB), and polyethylene terephthalate (PET). The Cu/Ni electrodes on PCB were electroplated with Au, while the Cu/Ni electrodes on PET were coated with Au using an electroless technique. The physicochemical properties were studied using optical microscopy, scanning electron microscopy, and energy-dispersive spectroscopy. Electrochemical characterization was done using cyclic voltammetry and electrochemical impedance spectroscopy. Biocompatibility assessment and sensor functionality tests were done by culturing SiHa cervical cancer cell lines on these sensors and impedance measurements. The results show that both electroplated and electroless sensors were biocompatible and suitable to monitor SiHa cell growth. Electrochemical migration effect was observed on the sensors where the reaction occurred at 1.2V DC for the PCB sensor and 1.0V DC for the PET sensor.

Evaluation of various mass spectrometry mode based on gas chromatography for quantifying the polycyclic aromatic hydrocarbon metabolites in human urine

Hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) are frequently used as biomarkers to assess human exposure to polycyclic aromatic hydrocarbons (PAHs), which are typically present in minute concentrations in the human body. Although several studies have outlined methods for measuring OH-PAHs in human urine, these approaches may have limitations concerning the range of compounds detected, the sample volume required for pre-treatment, accuracy, and instrument maintenance costs. Advances in mass spectrometry technology have facilitated the use of various mass spectrometry modes based on gas chromatography. It is essential to evaluate different mass spectrometry modes to identify a more reliable and practical method for quantifying OH-PAHs in urine. Our comparative analysis of three gas chromatography-mass spectrometry modes revealed that advanced electron ionization (AEI) mode exhibited greater sensitivity for determination compared to electron ionization (EI) mode in tandem mass spectrometry. The method validation criteria were satisfied by GC-AEI-MS/MS, which demonstrated acceptable measurement errors (MEs) ranging from -23.0 % to 19.5 %, recoveries between 81.6 % and 112.1 %, and precision levels below 10.1 %. Furthermore, the reliability and accuracy of the GC-AEI-MS/MS method were corroborated through Intraclass Correlation Coefficient (ICC) evaluation (values > 0.75), participation in external proficiency testing programs (G-EQUAS), and analysis of certified reference materials, which exhibited a relative deviation of <6.1 %. In summary, GC-AEI-MS/MS is a robust and reliable method for analyzing urine samples and conducting large-scale human biological monitoring. It was employed to determine 16 OH-PAHs in human urine as part of the China National Human Biomonitoring Program (CNHBM).

Development of compact electrolytic enrichment system for environmental tritium analysis.

The new electrolytic enrichment system with compact glass cell was designed. Three (Ni-Fe-Ni) electrodes are used, and electrolysis is carried out at a rate of 2.45g per h with constant current density of 120mA per cm2. This enrichment system allows the enrichment for small, limited sample volumes (e.g. Tritiated Water (HTO) recovered from air). With an initial water volume of 100ml, the tritium enrichment factor of 7 within 2days and a detection limit of 0.12Bq per L can be obtained by Liquid Scintillation Counter (LSC) measurement for 1000minutes, which is better than the direct measurement with 50ml sample water using large vial. It is also possible to perform the high enrichment process. The initial sample volume of 700ml enriched for 12days by manual refilling yields a tritium enrichment factor of around 43 and detection limit of 0.02Bq per L for 1000minutes of LSC measurement.

Microstructure and tribological property of laser cladding Stellite 6 alloy by laser remelting and ultrasonic surface rolling

Stellite 6 alloy was deposited onto the surface of 27SiMn steel using the laser cladding (LC) technique, which was then followed by laser remelting (LR) and ultrasonic surface rolling (USR).The surface roughness, microstructure, microhardness, surface residual stress, and wear resistance of LC, LR, and LR-USR samples were studied using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray stress analyzer, Vickers hardness tester, and material surface performance tester. The results showed that compared with LC, LR-USR significantly refined the surface dendrites of the cladding layer, with the average dendrite size decreasing from 16.37 μm to 6.92 μm. After USR, the samples converted from tensile residual stress (TRS) to compressive residual stress (CRS), and the high-density dislocations and strain generated in the grains near the surface of the cladding layer. The wear depth volume of the LR-USR samples was the smallest, showing typical abrasive wear.

Cloud detection sample generation algorithm for nighttime satellite imagery based on daytime data and machine learning application

Highly accurate nighttime cloud detection in satellite imagery is challenging due to the absence of visible to near-infrared (0.38–3 μm, VNI) data, which is critical for distinguishing clouds from other ground features. Fortunately, Machine learning (ML) techniques can more effectively leverage the limited wavelength information and show high-accuracy cloud detection based on vast sample volume. However, accurately distinguishing cloud pixels solely through thermal infrared bands (8–14 μm, TIR) is challenging, and acquiring numerous, high-quality and representative samples of nighttime images for ML proves to be unattainable in practice. Given the thermal infrared radiation transmission process and the fact that daytime and nighttime have the same source of radiance in TIR, we propose a sample generation idea that uses daytime images to provide samples of nighttime cloud detection, which is different from the traditional sample construction methods (e.g., manually label, simulation and transfer learning method), and can obtain samples effectively. Based on this idea, nighttime cloud detection experiments were carried out for MODIS, GF-5 (02) and Himawari-8 satellites, respectively. The results were validated by the Lidar cloud product and manual labels and show that our nighttime cloud detection result has higher accuracy than MYD35 (78.17%) and the ML model trained by nighttime manual labels (75.86%). The accuracy of the three sensors is 82.19%, 88.71%, and 79.34%, respectively. Moreover, we validated and discussed the performance of our algorithm on various surface types (vegetation, urban, barren and water). The results revealed that the accuracy of the three sensors over barren was found to be poor and varied with surface types but overall high. Our study can provide a novel perspective on nighttime cloud detection of muti-spectral satellite imagery.

Single-Molecule Detection of Serum MicroRNAs for Medulloblastoma with Biphasic Sandwich Hybridization-Assisted Plasmonic Resonant Scattering Imaging.

MicroRNA (miRNA) dysregulation is closely related to the occurrence and progression of medulloblastoma (MB). However, the full potential of serum circulating miRNAs in MB diagnosis is restricted by their ultralow abundance in peripheral blood due to blood-brain barrier. Here, we report the direct preamplification-free detection of aberrant expression of oncogenic miRNAs in serum from MB patients by proposing a simple yet robust single-molecule assay that combines biphasic sandwich hybridization in nucleic acids and the dark-field single-particle plasmonic imaging (B2S2PI). In this strategy, signal DNA was prehybridized with target miRNA in homogeneous solution to form sDNA-RNA complexes. Then the captured DNA strands with rationally adjusted surface densities could efficiently capture the sDNA-RNA complexes to generate a well-separated DNA-RNA sandwich structure. The combination of homogeneous and heterogeneous reactions enabled interface-mediated hybridization reactions to maintain molecular stability with fewer bases, making it suitable for the direct amplification-free assays of short miRNA targets. Labeling the DNA-RNA hybrids with plasmatic gold nanotags allowed nondestructive recognition and imaging of individual miRNA targets under mild conditions with high signal-to-noise ratio. By digitally counting and analyzing the bright plasmonic resonant scattering spots, B2S2PI enabled both the measurement of a low femtomolar concentration of circulating miRNA-21 in 5 μL sample volume within a turnaround of 2 h and the discrimination of single base mismatches. Moreover, B2S2PI was universal for detecting miRNAs with different sequences and secondary structures. Further analysis of clinical serum samples revealed that B2S2PI was capable of accurately distinguishing MB patients from noncancer controls with an area under the curve (AUC) of 0.99, which was superior to that of qRT-PCR. B2S2PI holds promise as a novel alternative means for single-molecule miRNA assay and sheds light on the circulating nucleic acid-based liquid biopsy of intracranial malignant tumors.