High-resolution Scanning Electron Microscopy Images Research Articles

Evaluating nickel removal efficacy of Filtralite under laboratory conditions: Implications for sustainable urban drainage systems

Our study deals with the critical issue of heavy metal pollution in urban runoff; we focused particularly on the threat posed by heavy metals such as nickel to living organisms and water resources owing to their toxicity at low concentrations and non-biodegradability. In this study, we evaluated the efficacy of Filtralite, a filtration medium with excellent hydraulic properties, in removing nickel from water through laboratory experiments and advanced simulation tools. We analysed the geochemical processes involved in nickel removal, including precipitation and adsorption. Importantly, we implemented an innovative approach for numerical modelling using HP1, by combining HYDRUS-1D and PHREEQC for modelling solute transport in porous media and geochemical reactions, respectively. The experimental results revealed that the Filtralite-laden column achieved a removal efficiency of 93.5 % for injected nickel. We observed a significant increase in the effluent pH from 7.0 to 11.5 during the interaction with Filtralite, affecting the solubility of the nickel phases. The model showed the highest nickel concentration in the initial column layers because of rapid chemical precipitation and adsorption upon contact with Filtralite. High-resolution scanning electron microscopy images confirmed the presence of amorphous precipitates around the soil particles, aligning with the changes in pH. This study contributes significantly to environmental engineering and urban water management by introducing an innovative numerical model in HP1 to accurately simulate the removal of nickel using Filtralite. These findings validate the efficiency of Filtralite in extracting nickel from aqueous solutions. Thus, Filtralite is a strong candidate for inclusion in sustainable urban drainage systems.

Green synthesis of nanocomposite based on magnetic hydroxyapatite using Falcaria vulgaris Bernh leaf extract to remove tartrazine dye from aqueous solution

To mitigate the adverse impacts of water pollution, the application of nanotechnology in dye removal and by-product reduction has the potential to establish a sustainable potable water supply. For these methodologies, the materials must involve exhibit qualities such as simplicity, high efficiency, eco-friendliness, reusability, and affordability. This study presents a novel porous magnetic hydroxyapatite nanocomposite coated with zinc oxide (Fe3O4@HAP@ZnO). Initially, zinc oxide nanoparticles were generated via a green synthesis method, where a zinc nitrate solution was combined with an aqueous extract from the Falcaria Vulgaris Bernh plant, serving as a reducing and stabilizing agent. These were then coated onto the magnetic hydroxyapatite.Verification of successful nanocomposite synthesis was obtained through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray spectroscopy (EDS), vibrating-sample magnetometer (VSM), High-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) images further substantiated these results. The synthesized nanocomposite exhibited a normal particle size distribution of approximately 89 nm. To achieve maximal decolorization efficiency, pertinent parameters were scrutinized and optimized through a detailed experimental design. Under optimal conditions, the nanocomposite's ability to decolorize tartrazine dye in an aqueous solution was evaluated. Remarkably, the highest observed efficiency approached 98 %, employing 0.07 g of the nanocomposite at 90 degrees Celsius, pH 6.4, over a span of 30 min. Further exploration of the nanocomposite's reusability revealed it could sustain an efficiency exceeding 90 % across 11 successive cycles, boasting an impressive capacity of 1398 (mgg-1).

SARS-CoV-2 Spike Protein Stimulates Macropinocytosis in Murine and Human Macrophages via PKC-NADPH Oxidase Signaling.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While recent studies have demonstrated that SARS-CoV-2 may enter kidney and colon epithelial cells by inducing receptor-independent macropinocytosis, it remains unknown whether this process also occurs in cell types directly relevant to SARS-CoV-2-associated lung pneumonia, such as alveolar epithelial cells and macrophages. The goal of our study was to investigate the ability of SARS-CoV-2 spike protein subunits to stimulate macropinocytosis in human alveolar epithelial cells and primary human and murine macrophages. Flow cytometry analysis of fluid-phase marker internalization demonstrated that SARS-CoV-2 spike protein subunits S1, the receptor-binding domain (RBD) of S1, and S2 stimulate macropinocytosis in both human and murine macrophages in an angiotensin-converting enzyme 2 (ACE2)-independent manner. Pharmacological and genetic inhibition of macropinocytosis substantially decreased spike-protein-induced fluid-phase marker internalization in macrophages both in vitro and in vivo. High-resolution scanning electron microscopy (SEM) imaging confirmed that spike protein subunits promote the formation of membrane ruffles on the dorsal surface of macrophages. Mechanistic studies demonstrated that SARS-CoV-2 spike protein stimulated macropinocytosis via NADPH oxidase 2 (Nox2)-derived reactive oxygen species (ROS) generation. In addition, inhibition of protein kinase C (PKC) and phosphoinositide 3-kinase (PI3K) in macrophages blocked SARS-CoV-2 spike-protein-induced macropinocytosis. To our knowledge, these results demonstrate for the first time that SARS-CoV-2 spike protein subunits stimulate macropinocytosis in macrophages. These results may contribute to a better understanding of SARS-CoV-2 infection and COVID-19 pathogenesis.

Adsorptive Removal of Selected Toxic Metals from Pharmaceutical Wastewater using Fe<sup>3</sup>O<sup>4</sup>/ZnO Nanocomposite

Pharmaceutical wastewater is a major source of environmental contamination, often containing toxic metals that pose significant threats to ecosystems and public health. This study explores the potential of magnetite/zinc oxide (Fe3O4/ZnO) nanocomposites prepared using a sol-gel method for the removal of lead, cadmium, and copper ions from pharmaceutical wastewater. The nanocomposite was characterized using X-ray diffraction (XRD), High-resolution scanning electron microscopy (HRSEM)/energy dispersive spectroscopy (EDS) and Fourier transmission infrared spectroscopy (FTIR). The XRD analysis of the nanocomposite identified 2θ (theta), of 31.7º, 34.4º, 36.2º, 47.5º, 56.6º, 62.8º, 66.3º, and 67.9º which correspond to the crystal planes of (100), (002), (101), (102), (110), (103), (200), and (112), respectively. The diffraction peaks associated with Fe3O4 at 2θ of 18.02º, 29.4º, and 43.3º, related to the crystal planes of (111), (220), and (400), respectively of the Fe3O4 phase. The HRSEM image of the nanocomposite exhibited spherical-shaped structures of Fe3O4/ZnO, and some irregular shapes. The effects of the contact time, dosage and temperature on the removal percentage of toxic metal ions were studied. Freundlich and Langmuir isotherm constants and correlation coefficients were determined and the equilibrium process was better described by the Langmuir isotherm. The adsorption process followed a second order kinetics and the thermodynamic parameters showed that the involved process was spontaneous. These findings contribute to the advancement of environmentally friendly technologies for the pharmaceutical industry and the broader field of wastewater remediation.

Efficient photocatalytic degradation of water pollutant Brufen using lutetium doped cerium oxide nanoparticles synthesized by chemical precipitation method

BackgroundPlants act the foremost source of molecules for the advancement of new drugs regarding anti-inflammatory action. In recent years, pharmaceutical compounds have been categorized as the emerging pollutants and have grabbed the attention of the researchers due to their existence in wastewater. They have been detected in drinking water which shows that the wastewater treatment plants are always not efficacious. These contaminants are pernicious if present in higher dosage and cause several risk factors to humans, animals, and aquatic systems. Ibuprofen, one of the most prescribed analgesics found to cause severe damage to stomach and intestine has been subjected to photocatalytic degradation using Lutetium doped Cerium oxide nanoparticles. The nanoparticles were synthesized using chemical precipitation method which is cost effective, simple, and ecofriendly. MethodsThe synthesized nanomaterial was characterized and confirmed using several analytical techniques like X-Ray Diffraction studies (XRD), Fourier Transform-Infrared Spectroscopy (FT-IR), UV-Diffuse Reflectance Spectroscopy (UV-DRS), High Resolution Scanning Electron Microscopy (HRSEM), X-Ray energy dispersive spectroscopy (EDAX), High Resolution Transmission Electron Microscopy (HRTEM), and X-ray Photoelectron Spectroscopy (XPS). Significant findingsXRD data revealed the cubic shape of the nanoparticles with approximate size of 6–12 nm. FT-IR study confirmed the presence of metal oxide peak at 550 cm−1 along with the peaks of other functional groups. HRSEM and HRTEM images confirmed cubic structure validating the XRD results. The band gap of the synthesized nanoparticles decreased from 3.25 eV to 2.90 eV in comparison with the pristine CeO2 with LuCeO2. XPS results revealed the oxidation state of lutetium as +3. The photocatalytic conditions were optimized and the optimization study confirms that the catalyst effectively degrades the drug. The degradation efficiency was calculated and was observed to be 92%. Real sample analysis was also performed using Brufen 200 tablet which confirms the practical application of the photocatalyst.

Reproducible Quantification of the Microstructure of Complex Quenched and Quenched and Tempered Steels Using Modern Methods of Machine Learning

Current conventional methods of evaluating microstructures are characterized by a high degree of subjectivity and a lack of reproducibility. Modern machine learning (ML) approaches have already shown great potential in overcoming these challenges. Once trained with representative data in combination with objective ground truth, the ML model is able to perform a task properly in a reproducible and automated manner. However, in highly complex use cases, it is often not possible to create a definite ground truth. This study addresses this problem using the underlying showcase of microstructures of highly complex quenched and quenched and tempered (Q/QT) steels. A patch-wise classification approach combined with a sliding window technique provides a solution for segmenting entire microphotographs where pixel-wise segmentation is not applicable since it is hardly feasible to create reproducible training masks. Using correlative microscopy, consisting of light optical microscope (LOM) and scanning electron microscope (SEM) micrographs, as well as corresponding data from electron backscatter diffraction (EBSD), a training dataset of reference states that covers a wide range of microstructures was acquired in order to train accurate and robust ML models in order to classify LOM or SEM images. Despite the enormous complexity associated with the steels treated here, classification accuracies of 88.8% in the case of LOM images and 93.7% for high-resolution SEM images were achieved. These high accuracies are close to super-human performance, especially in consideration of the reproducibility of the automated ML approaches compared to conventional methods based on subjective evaluations through experts.

Ultra-thin silver films grown by sputtering with a soft ion beam-treated intermediate layer

Silver thin films have wide-ranging applications in optical coatings and optoelectronic devices. However, their poor wettability to substrates such as glass often leads to an island growth mode, known as the Volmer–Weber mode. This study demonstrates a method that utilizes a low-energy ion beam (IB) treatment in conjunction with magnetron sputtering to fabricate continuous silver films as thin as 6 nm. A single-beam ion source generates low-energy soft ions to establish a nominal 1 nm seed silver layer, which significantly enhances the wettability of the subsequently deposited silver films, resulting in a continuous film of approximately 6 nm with a resistivity as low as 11.4 µΩ.cm. The transmittance spectra of these films were found to be comparable to simulated results, and the standard 100-grid tape test showed a marked improvement in adhesion to glass compared to silver films sputter-deposited without the IB treatment. High-resolution scanning electron microscopy images of the early growth stage indicate that the IB treatment promotes nucleation, while films without the IB treatment tend to form isolated islands. X-ray diffraction patterns indicate that the (111) crystallization is suppressed by the soft IB treatment, while growth of large crystals with (200) orientation is strengthened. This method is a promising approach for the fabrication of silver thin films with improved properties for use in optical coatings and optoelectronics.

Efficiency enhancement of perovskite-sensitized solar cell based on electrospun titania nanofibers coated in organic-inorganic hybrid metal trihalide nanocrystals

In this work, we have developed highly efficient, flexible, and thermally stable photoanode materials for perovskite-sensitized solar cells (PSCs). Methylammonium lead iodide (MAPbI3 or CH3NH3PbI3) coated TiO2 nanofibers (TNFs) were prepared by two step process. The cubic crystalline nature of MAPbI3 and the semi-crystalline nature of TNFs were confirmed by X-ray diffraction. The functional groups present in the photoanode materials were identified by Fourier-transform infrared spectroscopy. From UV–visible spectral studies, the absorption maximum of MAPbI3-coated TNFs was observed at 754 nm. High-resolution transmission electron microscopy and scanning electron microscopy images of MAPbI3 and TNFs showed a polycrystalline nature and uniform fiber structures, respectively. The highest electrical conductivity of 5.29 × 10−4 S/cm was achieved by the MAPbI3-coated TNFs photoanode, as measured by electrochemical impedance spectroscopy at room temperature. MAPbI3-coated TNFs, Spiro-OMeTAD, and gold chloride were used as the photoanode, hole transport material, and back electrode, respectively, in a PSC. A PSC constructed with MAPbI3-coated TNFs yielded an efficiency of 13.12%, bettering the 11.48% efficiency of a PSCs constructed from MAPbI3-coated TiO2 nanoparticles.

The study of CO2 reforming of methane over Ce/Sm-promoted NiCaAl catalysts

In this work, we synthesized Ce and Sm-promoted NiCaAl layered catalysts via co-precipitation and freeze-drying strategies for alleviating some problems, such as coke deposition and agglomeration of active sites, in dry reforming of methane. Employing such promoters leads to rising O2 vacancies on the catalyst's surface, resulting from adsorbing CO2 gas under the reaction. X-ray diffraction (XRD) analysis confirmed the formation of a hydrotalcite network. High-resolution transmission electron microscopy (HR-TEM) and field emission scanning electron microscopy (FE-SEM) images also indicated a wealth of nanocatalysts, well distributed on the surface and within a porous scaffold structure. The temperature-programmed reduction (H2-TPR) proved that cerium (H2 consumption = 1.2 mmol.g-1) could weaken the interactions between nickel and Ca/Al, leading to better reducibility than samarium (H2 consumption = 1.35 mmol.g-1). Moreover, the temperature-programmed deposition (CO2-TPD) showed the Ce-promoted catalyst possesses more basic sites (0.41 mmol.g-1) on its surface than the Sm-enhanced one (0.25 mmol.g-1). Consequently, the Ce-enhanced catalyst with a smaller crystallite size (8.9 nm), higher dispersion of Ni (10.8%), better reducibility, and more basic sites, which caused the highest methane conversion (82%), and H2/CO ratio (0.9) at 700 °C without any coke deposition after 5 h of time on stream.

Growth and characterization of gold nanoislands & quantum dots on marker-based SiO2/Si substrate for SEM resolution intercomparison studies

A scanning electron microscope (SEM) is the powerhouse tool of nanoscience & nanotechnology and the high resolution is one of the important parameters that decide the instrument’s quality. The reference materials (RM) like gold nanoislands or tin spheres on carbon substrate separated by a nanogap are often used to get the practically attainable resolution of the SEM instrument. Such RM contains millions of gold nanoislands and nanogaps but all of these RMs are non-traceable. Hence the practically obtained high resolution of an SEM remains doubtful unless and until intercompared with traceable RM. The development of a new SEM resolution test specimen sample with localized markers for the identification of a traceable critical dimension of a nanogap on a user-friendly SiO2/Si or Si3N4/Si chip is reported here. First, thin films of gold with thickness < 5 nm (ultra-thin film) and of about 10 nm (thin film) were deposited on a pre-patterned marker SiO2/Si chip to form the gold nanoparticles (Au NPs) by thermal annealing technique. The high-resolution SEM images show the formation of gold quantum dots (Au QDs) (average particle diameter <D> ∼ (18 ± 1) nm and average gap between two particles <S> ∼ (6 ± 1) nm) and gold nano-islands (Au NIs) (<D> ∼ (101 ± 3) nm and <S> ∼ (104 ± 2) nm). FESEM images show densely packed nano-islands exhibiting spherical geometry which is explained using dewetting mechanism followed by Ostwald ripening and coalescence resulting formation of Au QDs and Au NPs. Further, these marker-based resolution test chips can be used in inter or intra-comparison studies due to pre-patterned markers. First-time development of QDs on marker chip gives access to a particular nanogap among the millions of nanogaps present on the substrate, this type of RM will be used for inter-laboratory comparison studies in the future.

High-Resolution Scanning Electron Microscopy Imaging to Understand the Growth Kinetics of Nickel Nanorods.

In the present work, the growth kinetics of nickel nanorods inside commercially available Whatman nanoporous membrane is explored to achieve uniform deposition over a large area of the membrane. Uniform electrodeposition inside nanopores requires continuous presence of solute ions near the deposition site and reduction of ions. To control ion diffusion and reduction near the deposition site, the effect of DC potential and pulsed potential with various duty cycles and solution temperatures is analyzed. Time-dependent variation in deposition current is recorded for all experiments. For different experimental conditions, high-resolution scanning electron microscopy (SEM) image is acquired. SEM along with the current density profile helped to understand the deposition mechanism for various growth conditions. Experiments confirmed that pulse deposition with a small duty cycle is promising to achieve uniform deposition. Also, by changing the pulse duty cycle, a sectioned nanostructure can be obtained. Based on the electron microscopic observation for various deposition conditions used in this work, it is concluded that initially nickel ions adhere to the pore surfaces due to high surface energy. When a potential is applied, ions reduce and a hollow nanotube structure forms. With time, concentric growth continues by forming a solid nanorod structure.

Photovoltaic studies on iodine incorporated titania aerogel nanocomposites

Iodine incorporated titania aerogel nanocomposites were synthesized by the sol–gel method. The nanocomposites were obtained by varying the concentration of iodine as 0, 5, 10, and 20% with respect to the weight percentage of titania. All the synthesized nanocomposites retained the crystallinity and anatase phase, confirmed by X-ray diffraction studies. High-resolution scanning electron microscope images of nanocomposites showed the porous structure with agglomeration by increasing the concentration of iodine. The energy dispersive spectrum revealed the entry of the iodine into the titania aerogel. The absorption edge of the nanocomposites from the UV–Visible spectroscopy showed the red-shifted and thereby reducing the band gap with increasing iodine concentration. The photovoltaic performance of the synthesized iodine-incorporated titania aerogel nanocomposites was performed using as photoanode in the quasi-solid dye-sensitized solar cell and found that the efficiency is increasing with increasing iodine in titania aerogel. The photostability and reproducibility of the device were greater than the pristine aerogel.

Shale Oil Occurrence Mechanisms: A Comprehensive Review of the Occurrence State, Occurrence Space, and Movability of Shale Oil

Shale oil resources are important supplements for the gradually decreasing oil production from conventional reservoirs. Although the exploitation and development of shale oil have achieved considerable progress in the last decade, the commercial extraction of hydrocarbons from shales is still difficult, especially in the lacustrine sedimentary basins of China. One of the key points controlling the successful extraction of hydrocarbons from shale systems is the understanding of the occurrence mechanism of shale oil. This study comprehensively summarizes the theories and techniques to characterize oil occurrence state, occurrence space, oil content, and oil movability in shale systems. Sophisticated instruments, such as high-resolution scanning electron microscopy and high-energy ray imaging, were utilized to qualitatively analyze the pore networks of shales. Advanced physical experiments and numerical simulation techniques, including step-by-step rock pyrolysis, solvent extraction, and NMR, were introduced to characterize shale oil adsorption and movability. By the comparative analysis of the occurrence space, it is found that the image observation technique especially focuses on concentrated pores, such as organic matter-hosted pores. The fluid injection technology yields particular pore size information, which should be calibrated using other information. The 3D digital core, demonstrating the spatial distribution of minerals and pores, is an effective input for shale oil flow simulation. Geological controls analysis about oil retention in organic-rich shales has found that the inorganic matter pores and fractures are probably the “sweet spot” of shale oil, due to the low oil adsorption and high light hydrocarbons content. Many physical experiments measure the total free oil content but neglect the hydrocarbon–rock interaction and the sequential migration of hydrocarbon compounds. Thus, micro-scaled experiments measuring the hydrocarbon adhesion forces are needed to uncover the occurrence mechanism of shale oil in the future.

Challenges Confronted by Electron Microscopy in Microbe Detection

Electron microscopy has been contributing significantly to the study of microbes for biomedical, biological, and material science purposes in the world. Besides providing structural information, precise chemical analysis can be carried out by determining sample composition in thin films by Energy- Dispersive X-ray Spectroscopy (EDS) or Electron Energy Loss Spectroscopy (EELS), along with observing materials and specimens in the nano-level. It can also help in formulating new technologies to aid humans in countless applications. At times, when focusing an electron beam on any surface, various elastic and inelastic interactions occur within the material. A couple of essential issues that occur with obtaining high-resolution Scanning Electron Microscope images of microbes are - a) to get adequate contrast, one need to condense the charging time for small organic particles such as bacteria and viruses that require magnifications greater than 1000x, thus, an appropriate conducting surface is essential; &amp; b) biological specimens need to be first dehydrated from original condition, for the appropriate imaging performance for the Scanning electron Microscope. The prominent limitation to date yet to be unraveled in electron microscopy is that none of them reveal the phylogenetic diversity of the microorganisms present in the study habitat. Unless detection schemes are developed allowing at least 3 orders of magnitude lower electron doses, the ability of electron microscopy to study life cell processes at the nanoscale, although very attractive, probably remains an idea concept. This review summarizes the difficulty in microbe detection and numerous encounters faced by Electron Microscopy in doing so.

Microstructural effect of various polyaniline-carbon nanotube core-shell nanocomposites on electrochemical supercapacitor electrode performance

Various carbon nanotubes-polyaniline (CNT-PANI) core-shell nanocomposites such as multiwalled carbon nanotube-PANI (PAM), carboxylic acid functionalized MWCNT (cMWCNT)-PANI (PACM) and amine-functionalized MWCNT (nMWCNT)-PANI (PANM) core-shell composites are successfully prepared by in-situ chemical oxidation process using ammonium persulphate (APS). Fourier transform infrared spectrum (FTIR) analysis proves the bonding nature between CNT core and PANI shell in nanocomposites. High-resolution transmission electron microscopy (HRTEM) and Field emission scanning electron microscopy (FESEM) images confirm the nanometer-sized PANI layer over CNT or core-shell structure of CNT-PANI nanocomposites. Further, the specific capacitance of the PAM electrode is 647 Fg−1 at scan rate 1 mV s−1 and 491 Fg−1 at current density 1 Ag−1 through cyclic voltammetry (CV) and galvanostatic charge-discharge respectively (GCD) in H2SO4 (1 M) medium under an applied potential between −0.2 to +0.8 V. Among the other CNT-PANI core-sell electrodes, the PAM electrode exhibits the highest retention of specific capacitance of 98 % and maximum Coulombic efficiency of 100 % after 5000th cycles of galvanostatic charge-discharge in the same applied potential. Due to its high specific capacitance and exceptional capacitance retention, PAM composite was fabricated as symmetric supercapacitors. The highest specific capacitance of 483 Fg−1 at a scan rate of 1 mV s−1 and 268 Fg−1 at a current density of 1 Ag−1 in 6 M H2SO4 is found for PAM composite. The symmetric device delivered the maximum energy density of 37 Wh kg−1 at a power density of 166 W kg−1.

Optical analysis of Sr3 Gd(PO4 )3 :Pr3+ phosphors for lighting applications.

A series of praseodymium (Pr3+ ) ion activated Sr3 Gd(1-x) (PO4 )3 :xPr3+ (0 ≤ x ≤ 2.0mol%) phosphors were prepared and their structural, compositional and luminescence properties were investigated. The X-ray diffraction profiles indicate that the studied phosphors crystallized into body centred cubic structure and the Pr3+ ions have no influence on Sr3 Gd(PO4 )3 phase. The high-resolution scanning electron microscopy images show the agglomeration of particles that are inter-connected and form irregular shape Sr3 Gd(PO4 )3 structures. The excitation transitions corresponding to Pr3+ :3 H4 → 3 P2,1,0 transitions at 445, 471 and 483 nm, respectively, matched well with the emission of blue-light-emitting diode (LED) chip. The emission spectra show strong reddish-orange luminescence through 1 D2 → 3 H4 transition when excited at 445 nm blue wavelength. The synthesized phosphors have the potential to be used as reddish-orange lighting devices.

Effect of organic loading rates on the membrane performance of a thermophilic submerged anaerobic membrane bioreactor for primary sludge treatment from a pulp and paper mill

The effect of organic loading rates (OLRs) on membrane performance and mixed-liquor suspended solids (MLSS) properties were examined using a laboratory-scale thermophilic submerged anaerobic membrane bioreactor (ThSAnMBR) that treats primary sludge from a thermomechanical pulp mill. Membrane performance was evaluated by monitoring its flux and corresponding transmembrane pressure (TMP). Changes in membrane chemical and physical properties resulting from operating conditions were investigated using Fourier transform infrared (FTIR), scanning electron microscopy (SEM), contact angle, energy-dispersive X-ray analyzer (EDX), and pore size measurement. While MLSS properties are analyzed by X-ray photoelectron spectroscopy (XPS), zeta potential, and particle size distribution (PSD) analysis. Membrane performance and MLSS properties were studied at different OLRs ranging from 1.5 to 3.9 kg-TSS/m3d, and hydraulic retention times (HRTs) of 3–8 d. This study showed that the increased OLR reduced the membrane performance and degradation of the primary sludge, as well as the biogas yield. This result indicates that OLR of less than 1.5 kg TSS/m3d, HRT of 8d, and solids retention time (SRT) of 32d should be maintained to achieve stable membrane performance and better biogas production. Also, results showed that important changes occurred on the membrane morphology and MLSS characteristics under the tested operating conditions. High-resolution SEM images reveal distinct differences in the pore morphology between the virgin and used membranes indicating the effect induced by the operating conditions. Thermophilic temperature led to an expansion of membrane pores. Overall, the primary sludge from pulp and paper mills can be treated successfully by ThSAnMBR for methane production with stable membrane performance and high treatment efficiency.

Non contrast enhanced volumetric histology of blood clots through high resolution propagation-based X-ray microtomography

We have demonstrated the capability of laboratory propagation-based microtomography (miroCT) in non-destructive 3D virtual histopathology of human blood clots without any contrast agent. The volumetric information are valuable to understand the mechanical properties of clots which are crucial in selecting the most efficient mechanical thrombectomy method for clot extraction. Different clot types retrieved by mechanical thrombectomy from patient victims of acute ischemic stroke were evaluated through propagation-based microCT. The results were correlated with high-resolution scanning electron microscopy (SEM) images, confirming detected cellular and fibrillary structures. Calcifications appeared as glassy opacity areas with relatively intense signal on microCT images, also proved by energy-dispersive spectroscopy and X-ray diffraction. Hyperintense regions on the microCT corresponded to individual or compact aggregates of red blood cells, whereas fibrin dominated volumes appeared at consistently moderate to low normalized microCT values. Red blood cell shapes and sizes are consistent with the SEM observations. Together with other potential parameters, 3D porosity distribution and volume fraction of structures can be easily measured by microCT data. Further development of automated post-processing techniques for X-ray propagation-based micro/nanoCT, also based on machine learning algorithms, can enable high throughput analysis of blood clot composition and their 3D histological features on large sample cohorts.

Development and characterization of lime-based stucco for modern construction and restoration applications based on ancient stuccoes from the “El Cerrito” pyramid, Querétaro, Mexico

This work studied the physical-chemical characteristics of two lime-based stucco samples extracted from the “El Cerrito” archeological site in Querétaro, Mexico. Their compositional analyses are consistent with calcite, labradorite (clay mineral), sand size quartz and volcanic lithics, and organic compounds. Scanning Electron Microscopy (SEM) images confirmed the use of micro and submicron natural fibers. Energy Dispersive Spectroscopy semi-quantitative analysis (EDS-SEM) showed Al, Mg, Ca, C, Si, K, and O as the major element components. Inductively Coupled Plasma (ICP) quantitative analysis found Ca, Al, Fe, Mg, and K as the major components, and Ba, P, S, Sr, Mn, Cr, and V, as minor and trace elements that produce a compelling fingerprint. X-ray diffraction patterns reveal that these stuccoes are formed by calcite and labradorite crystalline phases. These analyses were used to develop and reproduce a new stucco formulation that can be used to conserve and restore archeological buildings and as modern wall finishing. The new stucco is a heterogeneous mixture of calcium hydroxide, pozzolan (alunite-kaolinite), fine quartz sand, and volcanic lithics as an aggregate, and soluble and insoluble natural fibers obtained from nopal pads as additives. A step-by-step methodology to prepare and apply the newly formulated stucco in a modern house as a wall finishing is reported. Pozzolan, calcium hydroxide, and water react to produce the pozzolanic effect acting as a non-hydraulic cement, while calcium hydroxide reacts with the atmospheric CO2 to form calcium carbonate. Portlandite conversion to calcite and the pozzolanic effect to obtain labradorite were shown by X-ray analysis and high-resolution SEM images of the newly applied stucco.

Poseidonamicus (Ostracoda) from the North Atlantic Ocean

Poseidonamicus is one of the most intensively studied genera among marine fossil ostracods due to its common occurrence in the world deep oceans and its distinctive morphological features. Many studies using Poseidonamicus have contributed to our understanding in a wide range of research topics, from evolutionary developmental biology to paleoenvironmental reconstruction. However, taxonomic confusion with Poseidonamicus species remains widespread because of subtle interspecific differences within this genus and limited taxonomic work on deep-sea faunas. The objectives of this paper are to update taxonomic information about Poseidonamicus species in the Pliocene–Quaternary North Atlantic, and to summarize paleobiogeographical distribution of all known Poseidonamicus species.We describe one new species, Poseidonamicus parasculptus n. sp., and present high-resolution scanning electron microscope images of North Atlantic Poseidonamicus major for the first time. Our distributional compilation shows that many Poseidonamicus species are confined to either the Indo-Pacific, theAtlantic, or the Southern Oceans. This information may provide identification guidance for future regional studies.