Hasil untuk "Microscopy"

D. Nečas, P. Klapetek

In this article, we review special features of Gwyddion—a modular, multiplatform, open-source software for scanning probe microscopy data processing, which is available at http://gwyddion.net/. We describe its architecture with emphasis on modularity and easy integration of the provided algorithms into other software. Special functionalities, such as data processing from non-rectangular areas, grain and particle analysis, and metrology support are discussed as well. It is shown that on the basis of open-source software development, a fully functional software package can be created that covers the needs of a large part of the scanning probe microscopy user community.

M. Holz, S. R. Heil, A. Sacco

Elham M. Ali, Ashraf Elsayed, Ahlam S. El Shehawy

Abstract A novel green and eco-friendly approach has been used to biosynthesize Ag–Fe bimetallic nanoparticles (Ag–FeBNPs) by using the water extract of the red alga species; Galaxaura rugosa. The surface plasmon resonance band of Ag–FeBNPs is positioned at 327 nm. X-ray diffraction analysis (XRD) illustrated the crystalline nature of biogenic nanoparticles with average diameters of 32.6 nm. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) showed that the particles have a crystalline spherical shape with a size range from 19.95 to 37.11 nm. Scanning electron microscopy (SEM) and Energy dispersive analysis (EDAX) give the surface morphology and elemental composition of Ag–FeBNPs, which are spherical in high intensity. Fourier transmittance infrared spectroscopy (FTIR) showed various stretching vibrations at 3421, 1598, 1384, 1035, and 865 cm−1. These findings suggest that biomolecules play a crucial role in forming and stabilizing Ag–FeBNPs. Zeta potential values show − 16.1 mV. This study demonstrates the promising future of Ag–FeBNPs for nanobiotechnology and nanoscience, offering an environmentally friendly and simple approach for nanoparticles biosynthesizing. In addition, the synthesized Ag–FeBNPs exhibit properties that make them suitable for potential applications in biomedical fields, environmental remediation, and catalysis.

Amanda M. Lopez, Yoonjung Choi, Zhi Zhou

Chlorella is a promising biofuel source due to its high lipid accumulation, rapid growth, and suitability for inland cultivation. However, how the Paramecium bursaria Chlorella virus 1 (PBCV-1) influences its triacylglycerol (TAG) accumulation remains underexplored. This data article provides a detailed description of the dataset generated to investigate TAG accumulation profiles in Chlorella infected with PBCV-1. The data, collected via high-resolution epifluorescence microscopy of over 4000 single cells across a full lytic cycle, includes measurements of TAG accumulation, chlorophyll fluorescence, and nuclear morphology, along with extracellular nutrient concentrations to rule out nutrient stress as a confounding factor. This dataset can be reused by researchers to develop new image analysis algorithms, train machine learning models, investigate virus-host interactions, and inform the development of more cost-effective biofuel production strategies.

Yujin Zhang, Evance Obara, Shuai Wang et al.

This paper focuses on the high-temperature tensile failure mechanism of RTM (resin transfer moulding)-made symmetric and asymmetric composite T-joints. The failure modes as well as the load-displacement curves of symmetric (three specimens) and asymmetric (three specimens) composite T-joints were determined by tensile tests at room and high temperatures. Progressive damage models (PDMs) of symmetric and asymmetric composite T-joints at room and high temperatures were established based on mixed criteria, and the result predicted from the aforementioned PDMs were compared with experimental data. The predicted initial and final failure loads and failure modes are in good agreement with the experimental results. The failure mechanisms of composite T-joints at different temperatures were investigated by scanning electron microscopy. The results reveal that while the failure mode of asymmetric T-joints at high temperatures resembles that at room temperature, there is a difference in the failure modes of symmetric T-joints. The ultimate failure load of symmetric and asymmetric T-joints at elevated temperatures increases and reduces by 18.4% and 4.97%, albeit with a more discrete distribution. This work is expected to provide us with more knowledge about the usability of composite T-joints in elevated temperature environments.

Yuantiao Xie, Dajian Huang, Wenjie Tang et al.

High drying shrinkage remains a major challenge in alkali-activated materials (AAM). In this study, porous palm fiber (PF) was modified with NaOH solution, saturated with water via vacuum impregnation, and incorporated as an internal curing agent into metakaolin-based AAM. The influence of PF on hydration behavior and microstructure was examined using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Vicat setting tests, and low-field nuclear magnetic resonance (LF NMR). The results showed that PF incorporation promoted the formation of additional hydration products and enhanced microstructural densification. Flexural strength was significantly improved, with the sample containing 1.5 % of 6 mm PF achieving the highest enhancement—an increase of 66.7 % compared with the control. After 28 days, a small amount of PF slightly increased the compressive strength. Vertical mortar expansion tests confirmed that PF effectively reduced drying shrinkage, with the most pronounced reductions observed in mixtures containing 1 % of 3 mm PF and 1.5 % of 6 mm PF, which decreased shrinkage by 42.9 % and 41.1 %, respectively, compared with the MK-AAM control sample (P0, 0 % PF). Overall, PF markedly mitigates drying shrinkage, improves flexural performance, and shows strong potential as a sustainable and environmentally friendly internal curing agent for AAM.

Elias Wagari Gabisa, Chavalit Ratanatamskul

Abstract The aim of this study was to develop a photothermal material modified with carbonization and ZnCl2 impregnation and supported by polyvinyl alcohol (PVA) for water purification using the waste coffee grounds. Scanning electron microscopy (SEM) characterization of the prepared material revealed that a significant surface modification was achieved due to the carbonization and ZnCl2 impregnation. X-ray diffraction analysis (XRD) pattern of the samples showed two broad peaks at 18.4° and 22.2°, this is due to the crystal planes of β-crystal phase structure, which indicates the existence of strong hydrogen bonds between the micro-structures and therefore less suspectable to chemical attack. Additionally, thermogravimetric analysis (TGA) result suggests a slight mass reduction between the temperature range of 65–75 °C implying the thermal stability of the prepared material. The produced modified material had a photothermal conversion efficiency of 74% and could produce vapor at a rate of 1.12 kg/m2h under 980 W/m2 irradiation at 1 sun. A significant reduction in Cu2+ ion concentration (83%), turbidity (91%), total dissolved solids (TDS) (61%), microbial load (95.6%), and total hardness (41.2%) were achieved. Therefore, waste coffee grounds can be considered as a future eco-friendly and low-cost candidate for water purification.

George T Mensah, Patrick F Ayeh-Kumi, Abraham K Annang et al.

<h4>Background</h4>Cryptosporidium is a ubiquitous enteric protozoan pathogen infecting humans, domestic animals, and wildlife worldwide. It is a waterborne pathogen with recognized zoonotic potential and a definite cause of diarrhea and nutritional disorders in institutional and community settings. One challenge facing the world's supply of clean drinking water is contamination from feces and soil. It has been established that small quantities of oocysts, the infective stage, can cause human disease. Also, their resistance to chlorination and other water treatment procedures has been demonstrated. Kpong, a community in the Lower Manya Krobo Municipality of the Eastern Region of Ghana, is one of the primary sources of water supply to Accra, the capital city of Ghana. Being able to determine the effectiveness of water treatment processes and identifying sources of contamination of this pathogen in our water bodies is thus of public health importance. The study aimed to conduct molecular epidemiology of Cryptosporidium spp. in the Lower Manya Krobo Municipality.<h4>Methodology/principal findings</h4>A total of 230 samples, 180 fecal samples from cattle and 50 water samples (tap water and well water) were collected from the following communities: Kpong, Akwernor, Ablotsi, Nuaso, and Atua, all in the Lower Manya Krobo Municipality. Samples were screened for Cryptosporidium by microscopy and PCR. The 18S rRNA gene was amplified by nested polymerase chain reaction (PCR), and the final product was sequenced. The prevalence of Cryptosporidium from the fecal samples was estimated as 10% (18/180) by microscopy, while all 50 water samples were negative. However, PCR gave the prevalence of Cryptosporidium as 47.8% (86/180) for fecal samples and 20% (10/50) for water samples. Based on the 18S rRNA gene, three sequenced samples showed high homology to C. parvum species. The phylogenetic analysis confirmed this as these sequences clustered with C. parvum sequences from other countries.<h4>Conclusion/significance</h4>Cryptosporidium parvum was identified as the persistent species in the study communities. This outcome supports the evidence that domesticated animals serve as potential reservoirs of zoonotic transmission of cryptosporidiosis. The persistence of cryptosporidiosis in cattle indicates its presence in the human population. In addition, the presence of Cryptosporidium parvum in the wells makes it alarming and necessary to consider a holistic approach such as One Health Strategies to identify and control cases in humans.

Bramantyo Bayu Aji, Yu-Hsiuan Huang, Masatsugu Oishi et al.

Selective emission of green light phosphor powder Y₄SiAlO₈N as the host material and Tb³⁺ as the activator was successfully achieved using spray pyrolysis (SP). Samples synthesized with various calcination temperatures and precursor concentrations indicated that the most suitable parameter for the synthesized powder is the calcination of 0.05 M Y_3.92SiAlO₈N:0.08Tb³⁺ at a temperature of 1600 °C. The effect of the selected parameters was substantiated by the high purity of the Y_3.92SiAlO₈N:0.08Tb³⁺ phase, as confirmed by X-ray diffraction (XRD) analysis. The Scherrer equation was used to calculate grain size. In addition, scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS) confirmed the presence of micron-sized particles, which matched well with the theoretical chemical composition. The specific surface area of the phosphor powder was determined using the Brunauer–Emmett–Teller method. Finally, fluorescence spectrometry was used to determine the luminescence properties. The correlation between the crystallinity of the phosphor powder and narrowing emission is also discussed.

Amir Hossein Salimi, Ali Shamshiri, Ehsan Jaberi et al.

Nanotechnologies present a promising application in the production of water to obtain potable water from natural sources by treatment. Clinoptilolite is an abundant and low-cost natural zeolite, which has adsorbent properties. Moreover, this study introduces a simple method for non-harmful natural adsorbent preparation and modification using different acids and bases with convenient and accessible desorption. The characterization methods used in this study are X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Response Surface Method (RSM) has been utilized to reflect the influence of operations variables in Design Expert 7.0. Other Variables, including the Effect of Modifications, contact time, the percentage of the dosage of adsorbent to the beginning (initial) pollutants concentration (D/C), and pH on total iron, were researched during the research procedure. The characterization results indicated that clinoptilolite nanoparticles were well prepared, and the preparation method was effective. Best modification Performance was shown in Z10(0.1 M Hydrochloric Acid dried by Air) at 24 h Setting time. The achieved results from Design Expert showed that at D/C and pH equal to 81.53 and 6.5, respectively, the optimal percentage of the iron removal is obtained with a value equal to 97.97%. In addition, Freundlich isothermal model best described the total iron adsorption process, and it has been observed that the maximum adsorption capacity is 50 mg/g for the total iron removal.

Emmalee J. Northrop‐Albrecht, William R. Taylor, Bing Q. Huang et al.

Abstract Extracellular vesicles (EVs) are of growing interest due to their potential diagnostic, disease surveillance, and therapeutic applications. While several studies have evaluated EV isolation methods in various biofluids, there are few if any data on these techniques when applied to stool. The latter is an ideal biospecimen for studying EVs and colorectal cancer (CRC) because the release of tumour markers by luminal exfoliation into stool occurs earlier than vascular invasion. Since EV release is a conserved mechanism, bacteria in stool contribute to the overall EV population. In this study, we assessed five EV separation methods (ultracentrifugation [UC], precipitation [EQ‐O, EQ‐TC], size exclusion chromatography [SEC], and ultrafiltration [UF]) for total recovery, reproducibility, purity, RNA composition, and protein expression in stool supernatant. CD63, TSG101, and ompA proteins were present in EV fractions from all methods except UC. Human (18s) and bacterial (16s) rRNA was detected in stool EV preparations. Enzymatic treatment prior to extraction is necessary to avoid non‐vesicular RNA contamination. Ultrafiltration had the highest recovery, RNA, and protein yield. After assessing purity further, SEC was the isolation method of choice. These findings serve as the groundwork for future studies that use high throughput omics technologies to investigate the potential of stool‐derived EVs as a source for novel biomarkers for early CRC detection.

G. Patterson, D. Piston

A. Bachtold, M. Fuhrer, S. Plyasunov et al.

We use electrostatic force microscopy and scanned gate microscopy to probe the conducting properties of carbon nanotubes at room temperature. Multiwalled carbon nanotubes are shown to be diffusive conductors, while metallic single-walled carbon nanotubes are ballistic conductors over micron lengths. Semiconducting single-walled carbon nanotubes are shown to have a series of large barriers to conduction along their length. These measurements are also used to probe the contact resistance and locate breaks in carbon nanotube circuits.

Xiaoyi Qu, Atul Kumar, Francesca Bartolini

Summary: Analyses of microtubule (MT) plus end dynamics at glutamatergic en passant boutons can be carried out in cultured primary neurons isolated from mouse or rat embryos or ex vivo in acute slices isolated from mice that had been electroporated in utero. Here, we describe a protocol for setting up and analyzing live image recordings of primary neurons and acute hippocampal slices expressing tagged versions of the MT plus end binding protein EB3 and the presynaptic vesicle markers vGlut1 or VAMP2.For complete information on the use and execution of this protocol, please refer to Qu et al. (2019).

Philipp Grosse, Aram Yoon, Clara Rettenmaier et al.

Understanding the changes that occur in catalysts during reaction are key to the rational design. Here, the authors use electrochemical transmission electron microscopy and time-resolved product analysis to unveil how cubic copper oxide catalysts evolve during electrochemical CO2 reduction, linking their structural transformations with their selectivity.

Zoya Zaheer, Samia A. Kosa, Mohd Akram

Crocin and CR interaction was studied by using UV–visible absorption spectroscopy, dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectroscopy and selected area election diffraction patterns. In an aqueous solution crocin as well as CR self-aggregated independently to form vesicles and truncated squares, respectively. The critical micellar concentration (=2.0 × 10−4 mol/L) of crocin was determined by using CR. Two breaks were observed in the wavelength maxima-[crocin] curves indicating that the vesicles and elongated aggregates exist in the crocin-CR system.TEM images and DLS results indicate that the shape, size, and the size distribution of crocin and CR aggregates depend on the experimental conditions. CR changed the morphology of crocin aggregates in aqueous solution. At high concentration, CR formed complex with crocin (formation constant = 492 mol−1 dm3) through intercalation interactions, whereas, CR encapsulated into the vesicles at lower concentrations.

Vahid A. Hosseini, Kjell Hurtig, Daniel Gonzalez et al.

Complex precipitation behavior of Cu-rich particles (CRPs) was investigated and simulated in continuously cooled and quench-aged super duplex stainless steel. Atom probe tomography (APT) and scanning electron microscopy showed that slow cooling resulted in nonuniform multimodal CRP precipitation and spinodal decomposition, while in the fast cooled and quench-aged conditions, more uniform precipitation of CRPs with no visible spinodal decomposition was found. Depletion of Cu, Ni, and Mn was observed in the ferrite next to the CRPs during growth, but not during dissolution. Some evidence of Ostwald ripening was seen after slow cooling, but in the quench-aged condition, particle coalescence was observed. Large CRPs disappeared next to a ferrite–austenite phase boundary after slow cooling when Cu was depleted due to the diffusion to austenite as also predicted by moving boundary Dictra simulation. Comparing Cu depleted areas next to CRPs analyzed by APT and moving boundary Dictra simulation of CRP–ferrite showed that the effective Cu diffusion coefficient during the early-stage precipitation was about 300 times higher than the Cu diffusion coefficient in ferrite at 475 °C. Using the effective diffusion coefficient and a size-dependent interfacial energy equation, CRP size distribution was successfully predicted by the Langer–Schwartz model implemented in Thermo-Calc Prisma. Applying a short aging time and continuous cooling increased the hardness and decreased the toughness values compared to the solution annealed condition. A nonuniform distribution of Cu in ferrite, the duplex structure, and partitioning of alloying elements among different phases are factors making CRP precipitation in duplex stainless steels complex.

Martin J. Booth

Tariq Aqeel, Heather F. Greer

A modified facile method is presented to synthesise quantum-sized zinc oxide nanoparticles within the pores of a mesoporous silica host (SBA-11). This method eliminates the 3 h alcohol reflux and the basic solution reaction steps of zinc acetate. The mesoporous structure and the ZnO nanoparticles were analysed by X-ray diffractometry, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, nitrogen sorption analysis and UV–VIS spectroscopy. These tests confirm the synthesis of ~1 nm sized ZnO within the pores of SBA-11 and that the porous structure remained intact after ZnO synthesis.

Nyaba Luthando, Dubazana Buyile, Mpupa Anele et al.

The main objective of this study was to develop an ultrasound-assisted dispersive solid-phase microextraction (UADSPME) method for separation and preconcentration of tellurium (Te) and thallium (Tl) in environmental samples prior to inductively coupled plasma-optical emission spectrometry determination. The MPC@SiO2@Fe3O4 nanocomposite was used as a nanoadsorbent in the UADSPME method. The nanocomposite was prepared using a coprecipitation and sol–gel method, and it was characterized using scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy and X-ray powder diffraction techniques. The Box–Behnken design and response surface methodology were used for the optimization of experimental parameters (such as pH, extraction time and mass of adsorbent) affecting the preconcentration procedure. Under optimized conditions, the limits of detection were 0.05 and 0.02 µg L−1 and the limits of quantification were 0.17 and 0.07 µg L−1 for Te and Tl, respectively. The precision expressed as the relative standard deviation (%RSD) was 2.5% and 2.8% for Te and Tl, respectively. Finally, the developed method was applied for the analysis of Tl and Te in real samples.