Transmitted Light Microscopy Research Articles

Mineralogy and Geochemistry of Listvenite-Hosted Ni–Fe Sulfide Paragenesis—A Case Study from Janjevo and Melenica Listvenite Occurrences (Kosovo)

The main goal of this paper is to determine the order of the paragenetic sequence and phase transitions of the Ni–Fe sulfide association hosted in listvenites. Listvenites are hydrothermally altered mafic and ultramafic rocks that are often associated with active tectonic settings, such as transform faults, suture zones, and regional extensional faults, usually in contact with volcanic or carbonate rocks. Listvenitization is displayed by a carbonation process when the original olivine, pyroxene, and serpentine group minerals are altered to Mg–Fe–Ca carbonates (magnesite, calcite, dolomite, and siderite), talc, quartz, and accessory Cr spinel, fuchsite, and Ni–Fe sulfides. The formed rocks are highly reactive; therefore, very often, younger hydrothermal processes are observed, overprinting the mineralogy and geochemistry of the original listvenitization products, including accessory Ni–Fe sulfide paragenesis. The studied samples of listvenites were collected from two locations in Kosovo (Vardar Zone): Janjevo and Melenica. The Ni–Fe sulfide textures and relationships with the surrounding listvenite-hosted minerals were obtained using reflected and transmitted light microscopy, while their chemical composition was determined using an electron microprobe. They form accessory mono-or polymetallic aggregates that usually do not exceed 100 μm in size disseminated in the studied listvenites. Generally, the paragenetic sequence of Ni–Fe sulfides is divided into three stages. The first pre-listvenite magmatic phase is represented by pentlandite and millerite. The second listvenite stage consists of Ni–Co bearing pyrite I (Ni content up to 11.57 wt.% [0.24 apfu], and Co content up to 6.54 wt.% [0.14 apfu]) and differentiated thiospinels (violarite + siegenite ± polydymite). The last, late listvenite stage is represented by younger gersdorffite−ullmannite and base metal mineralization: pyrite + marcasite + sphalerite + galena ± chalcopyrite ± sulfosalts. The findings obtained should help in the interpretation of many disseminated accessory Ni–Fe–Co mineralizations associated with mafic and ultramafic rocks worldwide.

Impact of clay minerals on reservoir sandstone properties: comparative study in Colombian eastern cordillera and middle Magdalena valley basins

The aim of this study is to examine how mineralogy influences the petrophysical properties, particularly porosity and permeability, of potential sandstone reservoirs in Colombia. It seeks to comprehensively understand how the presence of clay minerals impacts the overall quality of hydrocarbon reservoirs in the country. Samples of sandstones from reservoirs at various outcrops in the Eastern Cordillera and Middle Magdalena Valley basins were collected. Detailed analysis of mineralogy and petrographic characteristics of the samples was conducted through various analytical techniques such as transmitted light microscopy, X-ray diffraction, and scanning electron microscopy. Porosity and permeability were measured using automated permeametry and porosimetry equipment. The predominant composition of the analyzed reservoir rocks comprises quartz (45-50%), feldspar (35-40%), and clays (10-20%). These rocks were categorized into two distinct groups based on their permeability (K) and porosity (Φ), ranging from 0.009 to 29.220 mD and 1.88 to 20.75%, respectively. The presence of illite correlated with a reduction in both porosity and permeability, highlighting its negative impact on reservoir quality. Conversely, an elevated concentration of kaolinite was associated with favorable porosity and permeability. Samples with feldspar sericitization demonstrated inferior hydrocarbon storage quality. This study provides a deeper understanding of how mineralogy affects the petrophysical properties of sandstone reservoirs in Colombia. These findings are crucial for guiding exploration and production strategies in the Colombian oil industry, especially in challenging geological environments like those studied.

Prototyping in Polymethylpentene to Enable Oxygen-Permeable On-a-Chip Cell Culture and Organ-on-a-Chip Devices Suitable for Microscopy.

With the rapid development and commercial interest in the organ-on-a-chip (OoC) field, there is a need for materials addressing key experimental demands and enabling both prototyping and large-scale production. Here, we utilized the gas-permeable, thermoplastic material polymethylpentene (PMP). Three methods were tested to prototype transparent PMP films suitable for transmission light microscopy: hot-press molding, extrusion, and polishing of a commercial, hazy extruded film. The transparent films (thickness 20, 125, 133, 356, and 653 µm) were assembled as the cell-adhering layer in sealed culture chamber devices, to assess resulting oxygen concentration after 4 days of A549 cell culture (cancerous lung epithelial cells). Oxygen concentrations stabilized between 15.6% and 11.6%, where the thicker the film, the lower the oxygen concentration. Cell adherence, proliferation, and viability were comparable to glass for all PMP films (coated with poly-L-lysine), and transparency was adequate for transmission light microscopy of adherent cells. Hot-press molding was concluded as the preferred film prototyping method, due to excellent and reproducible film transparency, the possibility to easily vary film thickness, and the equipment being commonly available. The molecular orientation in the PMP films was characterized by IR dichroism. As expected, the extruded films showed clear orientation, but a novel result was that hot-press molding may also induce some orientation. It has been reported that orientation affects the permeability, but with the films in this study, we conclude that the orientation is not a critical factor. With the obtained results, we find it likely that OoC models with relevant in vivo oxygen concentrations may be facilitated by PMP. Combined with established large-scale production methods for thermoplastics, we foresee a useful role for PMP within the OoC field.

A novel three-part pharynx and its parallel evolution within symbiotic marine nematodes (Desmodoroidea, Stilbonematinae)

Stilbonematinae are nematodes commonly found in shallow marine sands. They are overgrown by a genus- and species-specific coat of chemoautotrophic sulphur-oxidizing ectosymbiotic bacteria which profit from the vertical migration of their hosts through the chemocline by alternately gaining access to oxidizing and reducing chemical species, while in return, the host feeds on its symbionts. The subfamily exhibits a large morphological variability; e.g. the anterior pharynx is cylindrical in genera possessing a voluminous coat, but species with a bacterial monolayer possess a distinctly swollen corpus and therefore a tripartite pharynx. Since 18S-based phylogenetic analyses do not show close relationships between corpus-bearing species, we investigated the pharynx morphology using phalloidin staining in combination with confocal laser scanning microscopy, transmission electron microscopy and light microscopy in order to assess an independent evolution. The class-wide stable position of the subventral pharynx ampullae was used as a morphological marker. Ampullae are positioned at the anterior-most end of the isthmus in Cyathorobbea, further posterior in Catanema and Robbea and inside the corpus in Laxus oneistus. We therefore conclude an independent evolution of corpus enlargements within Stilbonematinae. This further suggests that pharynx morphology is driven by the volume of the symbiotic bacterial coat rather than phylogeny. Based on an existing mathematical model, an enlarged corpus should enable its bearer to ingest food in smaller quantities, in gourmet style, whereas a cylindrical pharynx would restrict its bearer to ancestral gourmand feeding. A review of pharynx types of Nematoda showed that the Stilbonematinae pharynx is substantially different compared to other tripartite pharynges. The lack of pharyngeal tubes and valves, the undivided corpus and evenly distributed nuclei in the isthmus warrant the definition of the “stilbonematoid” three-part pharynx.

A Microscope Medley for High School Students

ABSTRACT Microscopy is crucial to much of biophysics. The variety of approaches to imaging exemplified by contemporary microscopes is remarkable, yet this breadth is generally unknown to students, limiting perceptions of biology, physics, and related fields and of potential career paths. We therefore created and implemented an outreach activity as part of a day camp that especially targeted low-income high school students. The students engaged with 3 very different microscopes: a simple transmitted light microscope; a light sheet fluorescence microscope; and a newly invented multicamera array microscope. With these instruments, we examined subjects such as transgenic zebrafish larvae with fluorescent immune cells, contrasting the various instruments’ capabilities, including resolution and field of view. Pre- and postactivity questions showed that the activity succeeded in expanding students’ understanding and appreciation of the varied aims and abilities of modern microscopes and moreover led to discussions of model organisms, biophysics, and science funding. Additional activities briefly illustrated the nature of digital images and mathematic manipulation. I describe here the activities and goals, as well as ways they can be generalized and implemented at other institutions with access to different sorts of imaging tools.

A versatile automated pipeline for quantifying virus infectivity by label-free light microscopy and artificial intelligence

Virus infectivity is traditionally determined by endpoint titration in cell cultures, and requires complex processing steps and human annotation. Here we developed an artificial intelligence (AI)-powered automated framework for ready detection of virus-induced cytopathic effect (DVICE). DVICE uses the convolutional neural network EfficientNet-B0 and transmitted light microscopy images of infected cell cultures, including coronavirus, influenza virus, rhinovirus, herpes simplex virus, vaccinia virus, and adenovirus. DVICE robustly measures virus-induced cytopathic effects (CPE), as shown by class activation mapping. Leave-one-out cross-validation in different cell types demonstrates high accuracy for different viruses, including SARS-CoV-2 in human saliva. Strikingly, DVICE exhibits virus class specificity, as shown with adenovirus, herpesvirus, rhinovirus, vaccinia virus, and SARS-CoV-2. In sum, DVICE provides unbiased infectivity scores of infectious agents causing CPE, and can be adapted to laboratory diagnostics, drug screening, serum neutralization or clinical samples.

Antimicrobial and Anesthetic Niosomal Formulations Based on Amino Acid-Derived Surfactants.

This work proposes the development of new vesicular systems based on anesthetic compounds (lidocaine (LID) and capsaicin (CA)) and antimicrobial agents (amino acid-based surfactants from phenylalanine), with a focus on physicochemical characterization and the evaluation of antimicrobial and cytotoxic properties. Phenylalanine surfactants were characterized via high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). Different niosomal systems based on capsaicin, lidocaine, cationic phenylalanine surfactants, and dipalmitoyl phosphatidylcholine (DPPC) were characterized in terms of size, polydispersion index (PI), zeta potential, and encapsulation efficiency using dynamic light scattering (DLS), transmitted light microscopy (TEM), and small-angle X-ray scattering (SAXS). Furthermore, the interaction of the pure compounds used to prepare the niosomal formulations with DPPC monolayers was determined using a Langmuir balance. The antibacterial activity of the vesicular systems and their biocompatibility were evaluated, and molecular docking studies were carried out to obtain information about the mechanism by which these compounds interact with bacteria. The stability and reduced size of the analyzed niosomal formulations demonstrate their potential in pharmaceutical applications. The nanosystems exhibit promising antimicrobial activity, marking a significant advancement in pharmaceutical delivery systems with dual therapeutic properties. The biocompatibility of some formulations underscores their viability. The proposed niosomal formulations could constitute an important advance in the pharmaceutical field, offering delivery systems for combined therapies thanks to the pharmacological properties of the individual components.

Early onset of enamel formation in Baka pygmy’s deciduous canines

ObjectiveOur aim was to evaluate by enamel microstructure analysis two hypotheses that would explain the early dental eruption in the Bakaparticularity, a shorter crown formation time and/or earlier onset of crown formation. DesignDeciduous canines corresponds to the best teeth to perform the analysis of enamel microstructure. Longitudinal ground sections of 21 deciduous canines from 12 individuals were studied with transmitted light microscopy. Cross-striations, striaes of Retzius (SR) and the neonatal line (NNL) enable to establish the prenatal crown formation time (preCFT), the postnatal crown formation time (postCFT), the crown formation time (CFT) as well as the daily secretion rate (DSR) and the enamel extension rate (EER) and their variation along crown formation. ResultsThe DSR and the EER in the Baka are similar than in other populations with an average DSR of 3.26 µm and EER of 18.18 µm. The preCFT was 154 days, the postCFT 265 days and CFT 419 days. Comparison with other population does not show difference in CFT. However, the preCFT and the postCFT differ, the first is higher and the second lower in the Baka than in other populations. Furthermore, the number of prenatal areas of enamel was greater in the Baka. ConclusionOur analysis suggests that the Baka does not distinguish by a different CFT but the onset of crown formation is earlier than in other groups. Therefore, the early dental eruption in the Baka results from an earlier onset of crown formation.

Paleoproteomic identification of the species used in fourteenth century gut-skin garments from the archaeological site of Nuulliit, Greenland

Until recently, the identification of the species of origin for skin and fur materials used in the production of archaeological clothing has been based on the analysis of macro- and microscopic morphological features and on the traditional knowledge of Indigenous groups. This approach, however, is not always applicable due to the deterioration of the archaeological objects. Paleoproteomics was used as an alternative approach to identify the species of origin of fifteen samples of various tissues from approximately 600-year-old garments found in Nuulliit, northern Greenland. Proteomics revealed that a limited group of marine and terrestrial mammals were used for clothing production. The results obtained from the analysis of multiple types of clothing and elements, such as sinew thread and gut skin, suggest that their applications were based on their properties. When conclusive assignment of a sample to a species via proteomics was not possible, the observation by transmitted light microscopy of feather and hair micromorphology, if not affected by diagenesis, was used to improve the identification. The proteomic characterization of animal materials used for clothing production in the Nuulliit archaeological context provides an insight into the practical knowledge and the strategies adopted by the local Indigenous community to exploit natural resources.

Light transmission in knitted fabrics through polymeric optical fiber insertion for advanced textile applications

Smart textiles are prominent in the textile industry, with applications in various technical areas such as medicine, architecture, sports, and esthetic purposes, among others. Within this concept, optical fibers are classified as passive smart textiles and are highly attractive for clothing lighting and monitoring physiological parameters. This study aimed to present methods for inserting polymeric optical fibers into weft single knitted fabrics and verifying the loss of luminosity in them, analyzing the technical feasibility of developing e-textiles to be applied in monitoring. For such, weft knitted fabrics were produced by altering the optical fiber insertion methodology, defined as inlay insertion and insertion in the course direction, each subdivided into different methods. Light transmission was verified using a laser pen connected to the optical fiber. Images were captured and analyzed using LILP software to verify and quantify the loss of luminosity in each insertion method. Light transmission microscopy was performed to evaluate the surface of the polymeric optical fiber used. For the insertion techniques performed, inlay and by course direction, the result obtained for signal transmission was satisfactory; however, the inlay insertion methods presented lower light emission but lower luminosity loss than the insertion by course direction. This result is very interesting because it enables the development of weft knitted fabrics from the use of optical fibers for application in various types of monitoring.

Wavy grain in sycamore maple (Acer pseudoplatanus) — a structural analysis of xylem and phloem

Summary Wavy grain (fiddle back) in trees has attracted the interest of both science and industry due to its aesthetic and economic importance. As the underlying causes of this particular structural feature in trees remain uncertain, this study investigates the possibility of non-invasively detecting wavy grain patterns within tree bark tissue of sycamore maple (Acer pseudoplatanus). Wavy grain, characterized by alternating light and dark stripes on the wood surface, is highly valued in the production of musical instruments. This research explores the potential of employing transmission light microscopy and microcomputer tomography (μCT) to examine the internal structure of phloem tissue to inspect whether the wavy grain structure found in the xylem continues in the bark. The investigation of phloem tissue proved challenging due to its irregular cellular arrangement. Nonetheless, slight phloem fibre deviations were observed in individual trees. However, no definite connection was found between the periodic oscillations of the xylem fibre tissue and the structure of the phloem in a given area. Variability in wavy grain expression among the xylem of the trees posed an additional challenge, with amplitudes and wavelengths differing across specimens. The application of μCT offered advantages over traditional sample preparation, enabling the study of the anatomical structure across larger areas and multiple depths without altering the specimen. This study sheds light on the potential of employing advanced imaging techniques to detect wavy grain patterns, providing insights that could benefit industries reliant on high-quality wood, such as musical instrument crafting and forestry.

Label-Free Techniques for Probing Biomolecular Condensates.

Biomolecular condensates play important roles in a wide array of fundamental biological processes, such as cellular compartmentalization, cellular regulation, and other biochemical reactions. Since their discovery and first observations, an extensive and expansive library of tools has been developed to investigate various aspects and properties, encompassing structural and compositional information, material properties, and their evolution throughout the life cycle from formation to eventual dissolution. This Review presents an overview of the expanded set of tools and methods that researchers use to probe the properties of biomolecular condensates across diverse scales of length, concentration, stiffness, and time. In particular, we review recent years' exciting development of label-free techniques and methodologies. We broadly organize the set of tools into 3 categories: (1) imaging-based techniques, such as transmitted-light microscopy (TLM) and Brillouin microscopy (BM), (2) force spectroscopy techniques, such as atomic force microscopy (AFM) and the optical tweezer (OT), and (3) microfluidic platforms and emerging technologies. We point out the tools' key opportunities, challenges, and future perspectives and analyze their correlative potential as well as compatibility with other techniques. Additionally, we review emerging techniques, namely, differential dynamic microscopy (DDM) and interferometric scattering microscopy (iSCAT), that have huge potential for future applications in studying biomolecular condensates. Finally, we highlight how some of these techniques can be translated for diagnostics and therapy purposes. We hope this Review serves as a useful guide for new researchers in this field and aids in advancing the development of new biophysical tools to study biomolecular condensates.

Polarity-driven distribution of the non-aqueous tear components during microdesiccation on flat glass surfaces

Spontaneous desiccation of microvolumes of tear from a healthy subject on flat glass surfaces produces highly reproducible supramolecular structures called tear microdesiccate. In the process, non-aqueous tear components organize four main radially distributed morphological domains (zones I, II, III, and transition band or TB) through non-well understood mechanisms. Tear lipids have been located in the outermost domains (ZI, TB), thus suggesting that tear components in microdesiccate are partitioned according to electric polarities. Using a combination of dark-field and contrast phase transmitted-light microscopy, we have now studied the impact on preformed tear microdesiccate of a series of six small-sized monohydric alcohols (methanol, ethanol, n-propanol, n-butanol, n-pentanol, 2-propanol; C1 through I-C3) ranked according to polarity index (P.I. 0.762–0.546). Water (P.I. 1.000) served as control. The study aimed to assess the influence of the electric polarity of the alcohols on the organization of the microdesiccate domains.The study revealed self-assembly as a mechanism underlying formation of the entire microdesiccate as shown by the fully disruptive effect of water on preformed tear microdesiccate and their reorganization following a new desiccation cycle. Devastating effects of the most polar alcohol in the assay (methanol) were observed particularly on the centermost domain (zone III), and secondarily on zone II. Contrarily, the less polar alcohols (C2 to C5) showed both fixative effects on crystalloids of ZII and ZIII and differential unveiling of filamentous structures in ZI and TB probably due to selective extraction of lipid-like components from these latter two domains. Those effects on microdesiccate from different subjects were highly reproducible, thus supporting the view that these tear specimens bear a common design.Microdesiccates from normal tears produced on flat glass surfaces are self-assembled structures based on a design including a radial gradient of charge polarities spanning from the lipid-rich outermost hydrophobic domain (ZI) to the centermost hydrophilic fern-like crystalloid-rich domain (ZIII).

Multimodal imaging analysis in silver fir reveals coordination in cellulose and lignin deposition.

Despite lignin being a key component of wood, the dynamics of tracheid lignification are generally overlooked in xylogenesis studies, which hampers our understanding of environmental drivers and blurs the interpretation of isotopic and anatomical signals stored in tree rings. Here, we analyzed cell wall formation in silver fir (Abies alba Mill.) tracheids to determine if cell wall lignification lags behind secondary wall deposition. For this purpose, we applied a multimodal imaging approach combining transmitted light microscopy (TLM), confocal laser scanning microscopy (CLSM), and confocal Raman microspectroscopy (RMS) on anatomical sections of wood microcores collected in northeast France on 11 dates during the 2010 growing season. Wood autofluorescence after laser excitation at 405 nm and 488 nm associated with the RMS scattering of lignin and cellulose, respectively, which allowed identification of lignifying cells (cells showing lignified and non-lignified wall fractions at the same time) in CLSM images. The number of lignifying cells in CLSM images mirrored the number of wall-thickening birefringent cells in polarized TLM images, revealing highly synchronized kinetics for wall thickening and lignification (similar timings and durations at the cell level). CLSM images and RMS chemical maps revealed a substantial incorporation of lignin into the wall at early stages of secondary wall deposition. Our results show that most of the cellulose and lignin contained in the cell wall undergo concurrent periods of deposition. This suggests a strong synchronization between cellulose and lignin-related features in conifer tree-ring records, as they originated over highly overlapped time frames.

Species Identification of Inuit Skin and Fur Clothing: Analyses of DNA, Hair Microscopy, and Macroscopical Identification

From approximately 1830 to 1940, through various expeditions to Siberia, Arctic North America, and Greenland, and through donations, the National Museum of Denmark acquired its collection of historical Inuit skin clothing. Unfortunately, original provenance information has been lost for 14% of the garments. In order to document the extensive collection, this study investigates three methods for species identification of animal skin: microscopy of hair, macroscopic identification, and DNA validation. Thus, the present study has two aims: first, to optimise and test hair microscopy for species identification by validating identifications by DNA analyses, and second, to use species identification to estimate the geographic and cultural provenance of Inuit skin clothing. Based on a dataset of well-documented clothing (for positive controls), this study describes an optimised species identification protocol via hair microscopy using transmitted light microscopy (TLM). We demonstrate that the TLM hair protocol is a reliable and inexpensive alternative to molecular approaches when macroscopic identification is doubtful and DNA validation or protein analyses are impossible. In this study we used photomicrographs to document the identifications of caribou (Rangifer tarandus), musk ox (Ovibos moschatus), species of the true seal family (Phocidae), domestic dog (Canis lupus familiaris), wolf (Canis lupus), Arctic fox (Vulpes lagopus), polar bear (Ursus maritimus), wolverine (Gulo gulo), ground squirrel (Urocitellus parryii richardsonii), ermine (Mustela erminea), and cattle (Bos taurus); these identifications can be used for future reference. We conclude that species identification analyses secure the documentation of garments and allow most objects to be contextualized by culture and geography. The studied garments are accessible at the museum website.

Structure of the oral tentacles of early ontogeny stage in brachiopod Hemithiris psittacea (Rhynchonelliformea, Rhynchonellida).

Brachiopods have the most complex lophophore in comparison with other lophophorates, i.e., phoronids and bryozoans. However, at early ontogenetic stages, brachiopods have a lophophore of simple morphology, which consists of the oral tentacles. Data on the ultrastructure of the oral tentacles is mostly missing. Nonetheless, it has recently been suggested that the structure of oral tentacles is ancestral for all lophophorates in general, and for brachiopods in particular. The fine structure of the oral tentacles in the brachiopod Hemithiris psittacea is studied using light microscopy, transmission and scanning electron microscopy, cytochemistry and confocal laser scanning microscopy. The oral tentacles have a round shape in transverse section, and four ciliary zones, i.e., one frontal, two lateral, and one abfrontal. Latero-frontal sensory cells occur among the frontal epithelium. Four basiepithelial nerves in the ciliary epithelium are colocalized with ciliary zones. Lophophores of simple morphology in phoronids and brachiopods are characterized by non-specified round forms of tentacles. In phoronids and bryozoans, tentacles have additional latero-frontal ciliary zones that function as a sieve during filtration. In most brachiopods, lateral cilia are involved in the capture of food particles, whereas latero-frontal cells are retained in the frontal zone as sensory elements. The oral tentacles of H. psittacea contain a coelomic canal and have distinct frontal and abfrontal longitudinal muscles, which are separated from each other by peritoneal cells. A similar structure of tentacle muscles occurs in all bryozoans, whereas in phoronids, the frontal and abfrontal tentacle muscles are not separated by peritoneal cells. We suggest that the lophophorates' ancestor had tentacles, which were similar to the tentacles of some phoronids with lophophore of simple morphology. We also assume that the structure of the oral tentacles is ancestral for all brachiopods and the specialization of brachiopod tentacles correlates with the appearance of the double row of tentacles.

Effects of different heating strategies on the joint properties during infrared welding of glass fiber reinforced polyamide 6

In infrared welding, the heating phase is the phase offering the highest flexibility of choice regarding the process parameters. In this phase, the process parameters such as the heating time, emitter power, and emitter-component distance can be individually selected and combined with each other. The defined heating phases have a different influence on the joining components. In this work, the effects of four heating strategies and their influence on the resulting temperature distribution over the joining surface, the possible thermal material degradation, the morphology of the joining zone, and the short-term tensile strength of the welded samples are investigated. In order to investigate the morphology, microsections are prepared which enable transmitted light microscopy of the black PA6 GF50 used. In summary, it can be concluded that different heating strategies have a different influence on the material even if the generated melt layer thickness is kept the same. Three of the four strategies result in material degradation on the joining surface. However, this has almost no effect on the resulting short-term strength of the weld. The results allow the interpretation that a high joining pressure compensates for the influence of the material damage by pressing the damaged material into the bead.

GEOCHEMICAL, MINERALOGICAL, AND PETROGRAPHICAL STUDIES OF IRONSTONES AROUND MOUNT PATTI, SOUTHERN BIDA BASIN, NIGERIA: IMPLICATIONS FOR QUALITY ASSESSMENT, PROVENANCE AND ENVIRONMENT OF DEPOSITION

The mineralogical composition, geochemistry, and depositional environment of the ironstone exposed on Mount Patti in the southern Bida Basin of Nigeria were assessed using integrated geochemical, mineralogical, and petrographic techniques. X-ray fluorescence spectrometry, X-ray diffraction, and transmitted light microscopy were used in geochemical, and petrographical investigations of fourteen representative ironstone samples. Average chemical analysis results showed that the concentrations of SiO2 (5.93 wt%), TiO2 (0.09 wt%), Al2O3 (10.76 wt%), and Fe2O3 (77.47 wt%) were as follows. The ironstone may be found in a shallow marine environment or non-marine environment if the concentrations of CaO, Na2O, K2O, MnO, and CuO are less than 0.40. This assertion is supported by the absence of sulfur oxide (SO3) in the examined samples and the bivariate plot of SiO2 versus Al2O3 and triangular plot of Fe-Mn-(Cu+Zn). Low levels of CaO and the absence of CO3 indicate that the environment is oxidizing. The iron's grade was calculated and found to be approximately 54.180%, which has been classified as low grade. The study also revealed that the ironstone contains a high amount of gangue materials (Al2O3 and P2O5), its silica (SiO2) content is within permissible limits, and it is devoid of harmful materials like sulfur. Based on petrographic studies, the floating contact displayed by the framework grains indicates that the iron cements were eodiagenetic in origin. Although it can be used more effectively as cast iron, sufficient beneficiation (to remove excess silica) can make it useful for iron and steel production.

Nanocomposites Based on Thermoplastic Acrylic Resin with the Addition of Chemically Modified Multi-Walled Carbon Nanotubes.

The main goal of this work was an improvement in the mechanical and electrical properties of acrylic resin-based nanocomposites filled with chemically modified carbon nanotubes. For this purpose, the surface functionalization of multi-walled carbon nanotubes (MWCNTs) was carried out by means of aryl groups grafting via the diazotization reaction with selected aniline derivatives, and then nanocomposites based on ELIUM® resin were fabricated. FT-IR analysis confirmed the effectiveness of the carried-out chemical surface modification of MWCNTs as new bands on FT-IR spectra appeared in the measurements. TEM observations showed that carbon nanotube fragmentation did not occur during the modifications. According to the results from Raman spectroscopy, the least defective carbon nanotube structure was obtained for aniline modification. Transmission light microscopy analysis showed that the neat MWCNTs agglomerate strongly, while the proposed modifications improved their dispersion significantly. Viscosity tests confirmed, that as the nanofiller concentration increases, the viscosity of the mixture increases. The mixture with the highest dispersion of nanoparticles exhibited the most viscous behaviour. Finally, an enhancement in impact resistance and electrical conductivity was obtained for nanocomposites containing modified MWCNTs.

Marine microfossils: Tiny archives of ocean changes through deep time.

Microorganisms have inhabited the oceans since the dawn of Earth. Some of them have organic walls and some produce mineral tests that are usually composed of carbonate minerals or silica. They can therefore be preserved with original parts during sedimentary deposition or fossilized through permineralization or carbonization processes. The most common marine fossil groups studied by micropaleontologists are cyanobacteria, coccolithophores, dinoflagellates, diatoms, silicoflagellates, radiolarians, foraminifers, red and green algae, ostracods, and pteropods. Dormant or reproductive cysts can also be used for determinations of the fossil microbiota. Microfossils can be studied in petrographic slides prepared from rocks or separated from loosely consolidated rocks by disaggregation or dissolution and wet sieving. Their presence is sometimes recognized by biomarkers. Transmitted light microscopy and reflected light stereomicroscopy are necessary for micropaleontological studies whereas scanning electronic microscopy (SEM) aids research on the tiniest fossils and reveals fine skeletal details. Microorganisms have influenced the oxygenation of water and the atmosphere, as well as Earth's carbon cycle and have contributed to the formation of sedimentary rocks. By studying microfossils, paleontologists depict the age of the rock and identify depositional environments. Such studies help us recognize periods of stress in Earth's history and understand their influence on living organisms. Biogenic rocks, made of microfossils, can be used as raw materials, such as fossil fuels, building stone, or additives for the food industry, agricultural, or cosmetic purposes.