Time Of Formation Research Articles

Wave ripples formed in ancient, ice-free lakes in Gale crater, Mars

Symmetrical wave ripples identified with NASA’s Curiosity rover in ancient lake deposits at Gale crater provide a key paleoclimate constraint for early Mars: At the time of ripple formation, climate conditions must have supported ice-free liquid water on the surface of Mars. These features are the most definitive examples of wave ripples on another planet. The ripples occur in two stratigraphic intervals within the orbitally defined Layered Sulfate Unit: a thin but laterally extensive unit at the base of the Amapari member of the Mirador formation, and a sandstone lens within the Contigo member of the Mirador formation. In both locations, the ripples have an average wavelength of ~4.5 centimeters. Internal laminae and ripple morphology show an architecture common in wave-influenced environments where wind-generated surface gravity waves mobilize bottom sediment in oscillatory flows. Their presence suggests formation in a shallow-water (<2 meters) setting that was open to the atmosphere, which requires atmospheric conditions that allow stable surface water.

Global Sn Isotope Compositions of Cassiterite Identify the Magmatic–Hydrothermal Evolution of Tin Ore Systems

Published Sn isotope data along with 150 new analyses of cassiterite and four granite analyses constrain two major tin isotope fractionation steps associated with (1) separation of tin from the magma/orthomagmatic transitional environment and (2) hydrothermal activity. A distinct Sn isotope difference across deposit type, geological host rocks, and time of ore deposit formation demonstrates that the difference in the mean δ124Sn value represents the operation of a unified process. The lower Sn isotope values present in both residual igneous rocks and pegmatite suggest that heavier Sn isotopes were extracted from the system during orthomagmatic fluid separation, likely by F ligands with Sn. Rayleigh distillation models this first F ligand-induced fractionation. The subsequent development of the hydrothermal system is characterized by heavier Sn isotope composition proximal to the intrusion, which persists in spite of Sn isotope fractionating towards isotopically lighter Sn during hydrothermal evolution.

Green Synthesis of Antibacterial CuO Nanoparticles Based on the Synergy Between Cornu aspersum Snail Mucus and Ascorbic Acid

Many biologically active compounds have been identified in the mucus of the garden snail Cornu aspersum, which are effective in the treatment of several diseases such as cancer, ulcers, wounds, etc. The incorporation of these compounds into the green synthesis of copper nanoparticles (CuONPs-Muc) was demonstrated in our previous study. Based on the synergistic effect of two reducing agents—C. aspersum snail mucus and ascorbic acid (AsA)—on CuSO4.5H2O, which also act as stabilizers of the resulting compound, a new method for the “green” synthesis of CuONPs-Muc is presented. Using two reducing agents has several advantages, such as forming spherical nanoparticles with a diameter of about 150 nm and reducing the formation time of CuONPs-Muc to 3 h. Analyses by ultraviolet–visible spectroscopy (UV-Vis) and Fourier transform infrared spectroscopy (FT-IR) show the formation of CuONPs-Muc, composed of a mixture of copper and copper oxide. This was confirmed by scanning electron microscopy combined with energy-dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). Another important advantage of CuONPs obtained by the new method with two reducing agents is the stronger inhibitory effect on the bacterial growth of some Gram-positive and Gram-negative bacterial strains, compared to CuONPs-Muc prepared with only one reducing agent, i.e., a fraction of mucus with an MW > 20 kDa.

Influence of Silica Fume (SF) Content on Passive Film Formation of Steel Reinforcement Inside Hardened Concrete

Corrosion is one of the causes of failure in reinforced concrete structures, and forming a passive film on the steel is essential for protection. Although several studies have looked at passive film formation in concrete pore solutions, few have considered its formation in hardened concrete and the influence of silica fume (SF) in the binder composition. This study aims to evaluate the influence of the SF content on passive film formation time in concrete. Periodic measurements assessed the electrical resistivity and corrosion current density of concrete samples containing 5%, 10%, 15%, and 20% SF. The alkalinity of the mixtures and the kinetics of the pozzolanic reaction were also monitored by XRD and titration tests. The control mixtures exhibited susceptibility to corrosion, regardless of the curing age evaluated. In contrast, the partial replacement of cement with SF accelerated the formation of the passive film on the steel surface, suggesting a delayed onset of corrosion due to modifications in the physical properties of the concrete. Also, the portlandite content and pH can predict passive film formation, with SF significantly accelerating this process.

Variability and coexistence of sexual and apomictic embryo sac development pathways in Fragaria x ananassa cv. ‘Camino real’

ABSTRACT While most apomictic plants have a defined type of gametophytic apomixis, the cultivars of strawberry reported various mechanisms of unreduced embryo sac formation. In this study, the main events of megasporogenesis and megagametogenesis during the sexual and apomictic processes of embryo sac formation were analyzed in the cultivar “Camino real”. Ovules at different developmental stages were sectioned and cleared and were observed using light microscopy and confocal laser scanning microscopy. Archesporial cells developed asynchronously and had diverse fates. These cells can alternatively be selected as mother cells, apomeiotic initials, persist in a resting stage, or degenerate. Other cells in the nucellus are able to acquire a functional megaspore identity. Apomixis did not involve callose deposition in their initial cells and derivatives. The initiation of apomixis was variable in time and eventually related to the interruption of the sexual process at pre-meiotic and post-meiotic stages of the ovule development. The occurrence of sexuality, apospory and diplospory of Antennaria and Taraxacum types is conserved across cultivars. The comparison with wild Fragaria species suggests that hybridization did not directly cause the observed phenotypic variation in apomixis mechanisms. An overview of the mode and time of unreduced sac formation can contribute to the development and management of clonal seed production in strawberry. The complex phenotypic variation additionally remains to be fully explained in light of emerging concepts regarding the regulatory mechanisms of plant reproductive development.

Formulation Study of a Poly(amino methacrylate) Film-Forming Solution for Transdermal Administration

Background/Objectives: The objective of this paper is to design a novel film-forming system (FFS) based on Eudragit® E PO (EuE) polymeric solutions, differing in volatile solvents (i.e., isopropanol and ethanol) and plasticizers (i.e., tributylcitrate, glycerine, triacetin and PEG 400). Methods: The physicochemical and mechanical properties of the FFS and dried films were evaluated in terms of formation time, stickiness, Tg, tensile strength, break elongation and Young’s modulus. The in vitro skin permeation studies were conducted on formulations containing caffeine and testosterone. Results: The FFS, consisting of EuE and PEG400 in isopropyl alcohol and ethanol (80:20, v/v), exhibited rapid film formation within about 5 min and the dried film allowed a high skin permeability compared to other formulations due to the ability to increase the thermodynamic activity of both drugs. When triiodothyronine (T3) was loaded as a model of a very low soluble drug, tocopherol polyethylene glycol succinate (TPGS) was added as a co-solvent and it allowed for the improvement of T3 retention in the skin. Conclusions: Among the formulative variables, the nature and the amount of plasticizer represent the most critical variables to obtain an EuE-based film with satisfying physical and biopharmaceutical properties.

Step characteristics and formation mechanism of strike slip faults in Wuerhe asphalt vein, Junggar Basin

In order to define the geometric characteristics, formation mechanism and fault wall movement direction of steps about mini-extensional shear strike-slip fault zone in Wuerhe asphalt vein. Field outcrop observation, 3D seismic data interpretation, fracture formation time and stress mechanism analysis were carried out. There is no friction in the vein section and the initial fracture shape is maintained. Not only negative steps but also steps is developed, and even steps and negative steps coexist in a cross section. The step is the microtension rupture surface associated with the strike-slip fault plane, which does not have the pointing significance of the fault wall relative movement. The outcrop features are typical, which overturns the consensus of domestic and foreign scholars based on the structural physics simulation experiments that the small steepness generated at the early stage of normal fault, reverse fault and strike-slip fault sections are all negative steps.

Evaluation of a Point-of-Care-Viscoelastic Coagulation Device in Hispaniolan Amazon Parrots (Amazona ventralis).

Viscoelastic testing evaluates the formation and lysis of a clot over time, allowing more complete assessment of patient hemostasis in real time, whereas traditional tests, such as prothrombin time and partial thromboplastin time, only measure coagulation factor function. Patient-side viscoelastic coagulation monitors are easy to use, portable, and provide faster turnaround time than commercial laboratories. Viscoelastic testing requires only 0.2 mL of blood and is useful in diagnosing and treating hemostatic disorders. Currently, there is no standardized coagulation testing method across bird species. In this cross-sectional study, a viscoelastic coagulation device, the Entegrion Viscoelastic Coagulation Monitor-Vet (VCM-Vet), was evaluated. Blood samples were obtained from 26 Hispaniolan Amazon parrots (HAPs) (Amazona ventralis) under manual restraint. Results were recorded on the device as graphical output with quantitative viscoelastic measurements. Results were reported using standard rotational thromboelastometry terminology, including clotting time, clot formation time, alpha angle, maximum clot firmness, clot firmness amplitude at 10 and 20 minutes after clot formation, and clot lysis at 30 and 45 minutes. The median clotting time was 463 seconds (reference interval: 56-1635 seconds), the mean clot formation time was 704.7 seconds (reference interval: 172-1697 seconds), the mean alpha angle was 27.3 (reference interval: 7-60), and the mean maximum clot firmness was 15.4 (reference interval: 7-25). Statistical analysis found that all parameters were normally distributed aside from clotting time in seconds. There was no appreciable breakdown of the clot during the 60-minute device runtime, and there was no significant difference in any parameter based on sex. The VCM-Vet produced clotting times for this population of HAPs and enabled the creation of reference intervals. Based on our findings, the VCM-Vet can be used to assess clot potential in HAPs and possibly other avian species.

Optimizing gelation time for cell shape control through active learning.

Hydrogels are popular platforms for cell encapsulation in biomedicine and tissue engineering due to their soft, porous structures, high water content, and excellent tunability. Recent studies highlight that the timing of network formation can be just as important as mechanical properties in influencing cell morphologies. Conventionally, time-dependent properties can be achieved through multi-step processes. In contrast, one-pot synthesis can improve both the efficiency and uniformity of cell encapsulation. Reaction kinetics are sensitive to temperatures and pH conditions, thus, monitoring gelation time across different conditions is essential for formulation. In this work, we choose tetra-poly(ethylene glycol) (TPEG) macromers as a model system to examine the relationship between the rate of polymer network formation and cell morphology. Previous studies of this system focused on reactions at neutral pH and room temperature, leaving much of the formulation space underexplored. We use Gaussian process regression (GPR) to minimize response surface errors by strategically selecting additional investigation points based on prior knowledge. Then we extend the knowledge from pre-trained data at neutral pH to a new surface at physiological pH. We find that the gelation time surface can effectively predict the aspect ratio of the encapsulated cells. Additionally, through focal adhesion kinase inhibition, we show that cell shape is influenced by the properties of the forming network in the initial hours as cells develop connections with the matrix. We demonstrate the utility of a high-throughput microrheology approach in enhancing fabrications of synthetic extracellular matrix and cell assemblies.

GENDERED RACIAL DISPARITIES IN FUNCTIONAL LIMITATIONS: EXPLORING THE ROLE OF LIFE-COURSE FAMILY CARE

Abstract Objectives This study addresses the dearth of research on culturally embodied factors influencing health disparities, focusing on cultural aspects such as family formation timing, living arrangements, familism, and family care responsibilities. By employing “intersectionality” and a life-course approach to “family care,” we aim to understand why minority women are vulnerable to functional limitations. Methods Data come from the MIDUS II, Refresher, and Milwaukee surveys, with a sample of Non-Hispanic Whites and Blacks (N=8,848; 18% Blacks; 53% Women). Measures of family care included age at first childbirth, number of biological children, single or nonmarital parenthood, child loss, co-residence with a disabled child, family caregiving history, and major grandparenting responsibilities. We identified racial disparities in family care profiles and assessed their contribution to health disparities. Results Adverse family care profiles were more common among women, particularly Blacks. Compared to White women, Black women were more likely to experience early and non-marital motherhood, current family care, and major grandparenting roles. Adverse family care profiles were linked to more functional limitations, with differing effects between Black and White women. While early childbearing was more detrimental to White women, caring for disabled family members had a greater adverse effect on Black women. Adverse family care profiles explained one-third of Black-White disparities in functional limitations. Discussion Our findings highlight the social costs of family care, disproportionately affecting minority women. They offer insights into public health policies and interventions aimed at easing the burdens of family care to improve their quality and length of life.

Hydrothermal uranium mineralization in the Tuyukan ore field (Northern Transbaikal region): time of formation of pitchblende mineralization and age of the source of the matter

Based on the study of local volumes of minerals using classical methods of isotope dilution and thermal ionization mass spectrometry (U–Pb ID TIMS), an isotopic study of pitchblende and galena was carried out at the Natali uranium ore occurrence (Northern Transbaikalia). For the first time, it was shown that pitchblende mineralization at the ore occurrence is Late Silurian (422±4 million years) age. Its formation is associated with early-mid Paleozoic collisional tectogenesis in the area of the Tonod uplift, accompanied by increased fluid activity. The results of analyzing the Pb isotopic composition in galena associated with pitchblende showed that it is enriched in the radiogenic isotopes 206Pb and 207Pb, the source of which was ancient (Precambrian) concentrations of uranium.

The persistent pool of HIV-1-infected cells is formed episodically during untreated infection.

Previous studies have shown that the majority of long-lived cells harboring persistent HIV-1 proviral genomes originates from viruses circulating in the year prior to antiretroviral therapy (ART) initiation, but a smaller proportion originates from viruses circulating much earlier in untreated infection. These observations suggest that discrete biological factors influence the entry and persistence of viruses into the persistent proviral pool, and there may be periods earlier in untreated infection with increased seeding. Therefore, we examined the timing of formation of the long-lived pool of infected cells that persists during ART in seven women (after a median of 5.1 years of suppressive ART) by comparing the phylogenetic distance between unique 3' half genome on-ART proviral sequences and longitudinally sampled pre-ART viral RNA sequences, focusing on the period >1 year prior to ART initiation (i.e., the "early" proviral pool). We constructed models of continuous entry into the persistent proviral pool prior to ART initiation and analyzed the fit of our experimentally derived data to these models. We found that the pattern of persistent proviral pool formation in five of seven participants is incongruent with a model of continuous entry, implying that persistent proviral pool formation can occur episodically during untreated infection. Notably, increased entry into the persistent proviral pool was not universally observed during acute infection, and the timing of enhanced early entry differed across the participants.IMPORTANCECells harboring HIV-1 proviruses that persist on antiretroviral therapy (ART) constitute the main barrier to an HIV-1 cure. Recent work has elucidated that the majority of persisting proviruses harbor HIV-1 variants circulating near the time of ART initiation, whether the proviruses are intact or defective, though a portion forms earlier in untreated infection. We examined the formation of the "early-forming" persistent proviral pool and found that in 5/7 participants, persistent proviral pool formation was episodic, rather than continuous, suggesting that there are host/biological factors that periodically enhance the formation of the persistent proviral pool. Further characterization of these factors will aid in the development of methods to abrogate their effect, thereby reducing the size of the persistent proviral pool.

Age Determination of Gem-Quality Green Vanadium Grossular (Var. Tsavorite) from the Neoproterozoic Metamorphic Mozambique Belt, Kenya and Tanzania

Gem-quality garnets, with their high closure temperature (750–800 °C), high transparency, uniform composition, and purity, offer promising prospects for U-Pb dating. Despite decades of recognition that garnets can be dated using the U-Pb method, direct dating remains extremely limited. Tsavorite is a rare gem-quality green vanadium-rich grossular hosted in the Neoproterozoic Metamorphic Mozambique Belt (NMMB). Until now, the accurate crystallization age of the tsavorite in Kenya and Lemshuku (Tanzania) has remained unknown. Here, we conducted in situ laser U-Pb geochronological analysis on gem-quality tsavorite samples from Tanzania and Kenya. U-Pb dating of tsavorite sourced from the Lemshuku mine (Tanzania) and the Tsavorite mine (Kenya) yielded ages of 643.9 ± 3.2 Ma and 617.4 ± 4.8 Ma, respectively. The high closure temperature of the U-Pb system within garnets renders it more inclined to preserve crystallization ages rather than documenting cooling events or metamorphic overprinting. Consequently, these ages are indicative of the tsavorite mineralization epochs. These findings align with the most significant metamorphic period documented in the Mozambique Belt, known as the East African Orogen, which occurred between 640 and 600 Ma. U-Pb data have revealed distinct formation times for each district. Dating specific deposits can provide more precise information about the origin of tsavorite, rather than solely relying on isotope or trace element data that have long been used for provenance studies of tsavorite.

Comparative analysis of the hemostatic effect of systemic recombinant Factor VIIa and exogenous fibrin monomer in an experimental model of heparinization and posttraumatic blood loss

This article presents the results of a study of the systemic hemostatic action of recombinant Factor VIIa in a rabbit model of heparin-induced coagulopathy and posttraumatic bleeding, compared to the administration of exogenous fibrin monomer. The coagulopathy was induced by a single intravenous injection of unfractionated heparin at a dose of 150 IU/kg 15 minutes before injury. Recombinant Factor VIIa (270 μg/kg) or fibrin monomer (0.25 mg/kg) was used as systemic hemostatic agents. One hour after administrating the agents, a standardized liver injury was inflicted, followed by an assessment of blood loss characteristics. Using rotational thromboelastometry and coagulation tests, animal venous blood was analyzed for coagulation time, alpha angle, clot formation time, maximum clot firmness, clot density at 10 minutes, activated partial thromboplastin time, prothrombin time, thrombin time, and fibrinogen concentration. Pharmacologically induced coagulopathy resulted in shifts to a hypocoagulable profile, associated with severe blood loss (1.9 times, p = 0.028) and high animal mortality (26.1%, p = 0.022) compared to the control group. Preventive administration of fibrin monomer or recombinant Factor VIIa reduced posttraumatic blood loss (by 5.4 times, p 0.001, and by 2.1 times, p = 0.009, respectively), resulting in a decrease in mortality rates. However, the administration of these agents did not correct the hypocoagulable profile as observed in thromboelastometry and coagulation tests. These data demonstrate the hemostatic effect of both agents, with a more pronounced effect after fibrin monomer administration, and suggest potential use of low doses of fibrin monomer in trauma-related hemorrhage. The mechanism of action of fibrin monomer requires further investigation. Therefore, fibrin monomer, a fibrinogen derivative obtained from blood plasma, could be a valuable candidate for managing wound bleeding in addition to recommended systemic hemostatics.

Increased sampling reveals the complex evolution of sauropod dinosaur tooth replacement rates.

Unlike most herbivores, sauropod dinosaurs evolved simple teeth that were replaced rapidly. Sauropod craniodental morphology is conserved relative to that of many archosaur clades, but tooth breadth and replacement rate vary substantially. Two neosauropod clades, Titanosauria and Diplodocoidea, independently evolved both narrow-crowned teeth and high tooth replacement rates among a suite of other convergent features. Brachiosaurids also evolved somewhat narrower-crowned teeth, but the two brachiosaurids whose tooth replacement rate has been examined to date have low replacement rates. Poor and uneven sampling across Sauropoda limits our understanding of the evolution of tooth replacement rate and related ecological inferences. To better understand the evolution of tooth replacement rate and tooth breadth, we integrated histological and tomographic data to nearly double the number of examined sauropod genera, focusing on improved sampling through the Cretaceous. We provide histological descriptions of the dentine and enamel of two Early Cretaceous taxa, Abydosaurus and Moabosaurus. The former has unusually thin daily increments in its dentine, indicating prolonged tooth formation times. The dentine of the latter is typical of what is observed in most sauropods, but it has enigmatic banding in its enamel. We performed ancestral state reconstruction on a time-calibrated phylogeny to show that the earliest macronarians and brachiosaurids retain the ancestral sauropod condition of relatively low tooth replacement rates (2-3 months to replace a tooth in each alveolus), whereas diplodocoids evolved much higher rates (2-5 weeks to replace a tooth in each alveolus). Early diverging somphospondylans had a broad range of tooth replacement rates. Broad-crowned teeth exhibit some correlation with low tooth replacement rates, whereas narrow-crowned teeth display a more variable relationship with replacement rate.

Age and origin of Bereinsky complex Granitoids of Kamensky Terrane of the Monghol-Okhotsk orogenic belt: results of U-Pb (ID tims) geochronological and Sm-Nd isotope-geochemical research

Dating of magmatic rocks from paleo-island arcs of orogenic belts helps to define the precise timing of subduction processes that took place during the formation of the orogen. Within the central (East Trans-Baikal) part of the Mongol-Okhotsk orogenic belt, the Kamensk island-arc terrane is an example of such paleo-island-arc complex. Its intrusive part is included into the Bereinsky complex, represented by a gabbro-diorite-tonalite-plagiogranite series of rocks demonstrating subduction geochemical characteristics. The dating of zircons from acidic rocks of this complex by the U–Pb classical method showed that they were produced in a narrow time interval – 203±1–205±1 Ma, which corresponds to Norian/Rhaetian boundary of the Late Triassic. Taking into account the previously obtained age of the diorites (254±5 Ma), the timing of formation of the entire series of intrusive rocks is about 50 Ma, thus indicating in the Late Permian – Late Triassic the subduction along the northern (in modern coordinates) margin of the Mongol-Okhotsk Paleocean beneath the Siberian paleocontinent. Diorites of the first phase have positive values ɛND(254MA) = 3.2–3.6 (TNd(DM) = 879–994 Ma), and plagiogranites – ɛND(205MA) = 2.3–3.5 (TNd(DM) = 859–1028 Ma), which points to the connection of these rocks with the substance of the depleted mantle source and is consistent with the Sm-Nd isotope characteristics of the juvenile crust of the Central Asian orogenic belt. This study was supported by Russian Science Foundation, grant no. 22-27-00775. The resources of the Shared Use Center for Isotope-Geochemical Research (Vinogradov Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk) were used in this work.

In preprints: oxygen and NFκB signals shift the timing of hindlimb formation.

In preprints: oxygen and NFκB signals shift the timing of hindlimb formation.

Problems of dating the Au-Pd mineralization of the Chudnoye deposit (the Subpolar Urals)

The ages values of the minerals that make up the ores of the Chudnoe deposit, established using isotope geochronology methods, do not allow us to correctly estimate the time of formation of Au-Pd mineralization due to the lack of reliable signs of their syngeneticity with gold. Based on linking isotope-geochronological data with the history of the geological development of the Subpolar Urals and the entire complex of endogenous and exogenous processes which determined the features of its geological structure and minerageny, the Early Paleozoic age of mineralization is substantiated. The similar age of the metarhyolites hosting the mineralization suggests not only a spatial, but also a paragenetic relations between ore mineralization and felsic volcanites. When studying the mineral composition and structural and textural features of ores, it is necessary to take into account the imposition of post-ore processes, especially the most powerful metamorphism manifested in the Subpolar Urals, the peak of which occurred in the Upper Paleozoic (~250 Ma).

Impact of direct oral anticoagulants on ROTEM® variables; a sample size-calculated experimental study

Direct oral anticoagulants (DOAC) are increasingly common, with bleeding events associated with elevated plasma concentrations. Rotational thromboelastometry (ROTEM), a point-of-care tool for assessing secondary hemostasis, has demonstrated a correlation with increasing concentrations of DOAC. However, previous studies have only partially explored this relationship. The primary aim in the current study was to investigate the impact of increasing rivaroxaban concentrations on clotting time (CT) in the EXTEM assay. The secondary aims were to investigate the impact of increasing rivaroxaban concentrations on clot formation time (CFT) and α-angle (AA) and to investigate the impact of increasing concentrations of dabigatran and apixaban on CT, CFT and AA. Blood from 12 healthy volunteers was spiked to anticipated concentrations of rivaroxaban, dabigatran and apixaban at 0, 50, 100, 200, 500 and 1000 µg/L each. Blood with these varying concentrations was analyzed in four different ROTEM assays and CT, CFT and AA were extracted. CT increased linearly with increasing concentrations of all three DOACs. Rivaroxaban and dabigatran spiked blood showed an increase in CT-EXTEM for the 200–1000µg/L concentrations, compared to baseline, and apixaban for the 500–1000 µg/L concentrations. CFT and AA were affected only in supratherapeutic concentrations for all tested DOACs and primarily in the INTEM assay. Among the tested DOACs, apixaban demonstrated the least impact on CT across all assays. In conclusion, ROTEM-derived CT measurements can serve as surrogate markers for DOAC concentrations.

EDGE: Dark matter core creation depends on the timing of star formation

EDGE: Dark matter core creation depends on the timing of star formation