Quantitative Analysis Of Distribution Research Articles

ATRA Can Correct Impaired Proplatelet Formation By Regulating HIF-1α/SPHK2/S1P Axis in ITP

Introduction Under normal physiological conditions, the bone marrow (BM) niche is hypoxic, and sustained and consistent oxygen gradients result in stable physiological hypoxia. Hypoxia inducible factor (HIF) is central to mediating the cellular response to hypoxia. Whether hypoxia gradients regulate megakaryocyte (MK) differentiation and maturation and the possible mechanisms of these actions remain unknown. Our previous data showed that impaired proplatelet formation (PPF) contributed to the development of thrombocytopenia in ITP. Recent studies suggest that the S1P signaling pathway in MKs plays a critical role in PPF ( Blood, 2013; J EXP MED, 2012). To further explore the underlying mechanism of impaired PPF in ITP, we found that HIF-1α/SPHK2/S1P axis-mediated cytoskeletal reorganization was defective in the PPF of ITP. All-trans retinoic acid (ATRA), which has been shown to be a promising treatment option for ITP patients in our clinical studies ( Blood, 2021; Lancet Haematology, 2017; Lancet Haematology, 2021), could restore cytoskeletal reorganization and correct impaired PPF. Methods Thirty patients with newly diagnosed ITP and 30 healthy donors were included in our study. The 30 ITP patients received ATRA at a dose of 10 mg orally twice daily for 12 weeks. Bone marrow samples were taken before the first medication (Day 0) and after 12 weeks of ATRA therapy (Day 85). We employed an imaging cytometry platform to perform a comprehensive quantitative analysis of MK distribution and hypoxic status in the bone marrow microenvironment of ITP. Targeted and untargeted metabolomic profiling through metabolomic analysis was performed to explore the relationship between the metabolome and ITP. Results We analyzed the hypoxic status of MKs in the endosteal niche and perivascular niche. In healthy controls, MKs in the perivascular niche exhibited a hypoxic profile, defined by robust HIF-1α expression and strong retention of pimonidazole. MKs in the endosteal region were less hypoxic. These results reflect a spatial hypoxia gradient in the bone marrow microenvironment. In contrast, we found that, irrespective of their location, ITP MKs displayed less hypoxia with no defined spatial gradients. ITP-MKs in the perivascular niche displayed altered cytoskeletal reorganization and impaired proplatelet formation (PPF). Metabolomics data revealed a decreased S1P level in ITP patients. Downregulated sphingosine kinase 2 (SPHK2) in MKs suppressed S1P production. S1P was essential for cytoskeletal reorganization and PPF regulation. In addition, we demonstrated that hypoxia inducible factor-1α (HIF-1α) mediated SPHK2 activation and S1P production. These data suggested that a disrupted hypoxia gradient contributed to impaired PPF via the HIF-1α/SPHK2/S1P axis. We then investigated the effect of ATRA on PPF. The ITP patients received ATRA at a dose of 10 mg orally twice daily for 12 weeks. For patients who received ATRA, S1P levels, HIF-1α and SPHK2 expression levels were increased compared with the pretreatment levels. And ATRA corrected impaired PPF and restored cytoskeletal reorganization by upregulating HIF-1α. Conclusions A disrupted hypoxia gradient contributed to impaired PPF in the ITP bone marrow environment via the HIF-1α/SPHK2/S1P axis. The ATRA-induced correction of impaired PPF is a potential mechanistic explanation for the clinical efficacy of ATRA in ITP.

Unpolarized transverse-momentum dependent distribution functions of a quark in a pion with Minkowskian dynamics

The unpolarized twist-2 (leading) and twist-3 (subleading), T-even, transverse-momentum dependent quark distributions in the pion are evaluated for the first time by using the actual solution of a dynamical equation in Minkowski space. The adopted theoretical framework is based on the 4D homogeneous Bethe–Salpeter integral equation with an interaction kernel given by a one-gluon exchange, featuring an extended quark-gluon vertex. The masses of quark and gluon as well as the interaction-vertex scale have been chosen in a range suggested by lattice-QCD calculations, and calibrated to reproduce both pion mass and decay constant. The sum rules to be fulfilled by the transverse-momentum dependent distributions are carefully investigated, particularly the leading-twist one, that has to match the collinear parton distribution function, and hence can be scrutinized in terms of existing data as well as theoretical predictions. Noteworthy, the joint use of the Fock expansion of the pion state facilitates an in-depth analysis of the content of the pion Bethe–Salpeter amplitude, allowing to calculate the gluon contribution to the quark average longitudinal fraction, that results to be ∼6%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim 6\\%$$\\end{document}. The current analysis highlights the role of the gluon exchanges through quantitative analysis of collinear and transverse-momentum distributions, showing, e.g. for both leading and subleading-twists, an early departure from the widely adopted exponential fall-off, for |k⊥|2>m2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|\ extbf{k}_\\perp |^2> m^2$$\\end{document}, with the quark mass ∼ΛQCD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim {\\varLambda }_{QCD}$$\\end{document}.

Transient behavior of liquid water distribution in a lung-inspired PEM fuel cell

Water management is a crucial aspect of hydrogen fuel cell operation because inadequate management can lead to significant losses in mass transport, limitations in oxygen diffusion, and membrane durability issues. This study investigates the impact of various operational conditions on the initial formation and evolution of liquid water content and distribution, as well as water evacuation, within a lung-inspired PEM fuel cell with a 50 cm2 active area. A series of experiments were conducted to assess the effects of cell pressure, relative humidity of the reactant (anode and cathode), temperature, and cell current density. Neutron imaging was utilized as it has been shown to be an effective technique for quantitative analysis of water distributions. The results indicate that water initially appears in the sponges located in the central region of the cathode, but due to considerable back-diffusion, water predominantly accumulates in the area of the anode channels in contact with the cathode sponges. The amount of water in the cell increases faster when the relative humidity of the cathode and anode is higher, and high pressure and low temperature also favours water accumulation. After the experiments, the design of the cathode sponge facilitates faster water evacuation compared to the anode side. Overall, this study offers valuable insights into the behaviour of water in a hydrogen fuel cell and the factors influencing its distribution.

Accurately 3D neuron localization using 2D conv‐LSTM super‐resolution segmentation network

AbstractNeuron localization is a fundamental step in the neuron morphology reconstruction and quantitative analysis of cell counting and spatial distribution. The recent development of labelling and imaging techniques has resulted in growing demand for automatic neuron localization methods of 3D neuronal microscopy images. However, accurately localizing touching neurons remains a challenge. To address this issue, a novel method utilizing a super‐resolution segmentation network based on 2D Conv‐LSTM and a region growing method are proposed. This network can map and detect individual neurons in higher resolution space, allowing for the separation of closely touching neurons with reduced resource consumption. Subsequently, a region growing method is employed to localize neurons accurately. This method is evaluated using neuronal images generated by TDI‐fMOST. This method achieved neuron localization with an F1 score of 0.91. In comparison, other automatic localization methods achieved F1 scores lower than 0.85. It is also demonstrated that our network has fewer computational requirements compared to 3D neural networks. This method is promising for accurately localizing neurons in large‐scale neuron images.

High-precision zircon age spectra record the dynamics and evolution of large open-system silicic magma reservoirs

The emplacement history and thermal evolution of subvolcanic magma reservoirs determine their longevity, size, and ability to feed volcanic eruptions. As zircon saturation is dependent on melt temperature and composition, quantitative analysis of zircon age distributions provides insight into the timing and magnitude of intensive parameter variations during the lifetime of a magma reservoir. Here we present chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon crystallization ages and in-situ zircon trace-element geochemistry for a suite of caldera-related, coeval plutonic and volcanic units of the Permian Sesia Magmatic System (northern Italy). This dataset documents the protracted growth and evolution (∼1 Myr) of a voluminous (>1000 km3), upper crustal (3.5–2.0 kbar) silicic magma reservoir. Systematic changes in zircon composition with time reveal episodic intrusions of new magma into a single, progressively differentiating reservoir which was dominantly kept at high crystallinity conditions (>60 vol.%). The volcanic and plutonic units both show dispersed and heterogeneous CA-ID-TIMS age distributions. A stochastic, thermodynamics-based zircon saturation model accounting for fractional crystallization, recharge and thermal rejuvenation effects on zircon growth and stability in a rhyolitic magma body reproduces the observed distributions of zircon U-Pb ages. Model results suggest that zircon compositional variability and crystallization age heterogeneity, characteristic of the Sesia and other large silicic systems, distinguish open- and closed-system magmatic processes. Specifically, an increase of the mass of crystallized zircons over time is the hallmark of thermally and chemically mature magma reservoirs, capable of producing voluminous eruptions upon changes in the thermal and mechanical state of the system. Conversely, a decrease in crystallized zircon mass over time characterizes systems where crystallization dominates over magma mobility, hindering substantial mass release during eruptive events. We suggest that quantitative analyses of dispersed zircon crystallization age distributions obtained with high-precision techniques can be applied to the plutonic and volcanic record to identify mature silicic magma reservoirs whose properties and storage conditions allowed for catastrophic caldera-forming eruptions. This work provides the petrologic community with a new tool to investigate the genesis and evolution of zircon-bearing intermediate to silicic intrusive magmatism and caldera-forming volcanism through time and across tectonic settings.

Thermal Deformation Characteristics and Dynamic Recrystallization Mechanism of Incoloy 800H Alloy under Different Deformations

Incoloy 800H alloy has excellent high‐temperature mechanical properties and broad application prospects. However, the dynamic recrystallization (DRX) behavior of this alloy at different deformations has been little studied. The thermal deformation characteristics and DRX mechanisms of Incoloy 800H alloy are studied by thermal compression tests. Quantitative analysis of grain size, DRX fraction, misorientation distribution, and twin boundaries under different deformation degrees is conducted using electron‐backscattered diffraction. Furthermore, the evolution characteristics of dislocations and grains are observed through transmission electron microscopy. It is found that the proportion of DRX improves with increasing deformation significantly. In the DRX process, discontinuous DRX (DDRX) is the main nucleation mechanism, while continuous DRX (CDRX) serves as an auxiliary nucleation mechanism. As the deformation increases, the CDRX + DDRX mechanisms can also be observed simultaneously in the high‐density dislocation region near the grain boundary. In addition, the ratio of ∑3 boundaries first decreases and then increases as the deformation increases. The initial twins gradually disappear due to the increase in deformation, and new twins are formed within the DRX grains. Twins can promote grain boundary bulging, provide more nucleation sites for DRX, and have a significant promoting effect on DRX.

PyCreas: a tool for quantification of localization and distribution of endocrine cell types in the islets of Langerhans.

Manifest diabetes, but also conditions of increased insulin resistance such as pregnancy or obesity can lead to islet architecture remodeling. The contributing mechanisms are as poorly understood as the consequences of altered cell arrangement. For the quantification of the different cell types but also the frequency of different cell-cell contacts within the islets, different approaches exist. However, few methods are available to characterize islet cell distribution in a statistically valid manner. Here we describe PyCreas, an open-source tool written in Python that allows semi-automated analysis of islet cell distribution based on images of pancreatic sections stained by immunohistochemistry or immunofluorescence. To ensure that the PyCreas tool is suitable for quantitative analysis of cell distribution in the islets at different metabolic states, we studied the localization and distribution of alpha, beta, and delta cells during gestation and prediabetes. We compared the islet cell distribution of pancreatic islets from metabolically healthy NMRI mice with that of New Zealand obese (NZO) mice, which exhibit impaired glucose tolerance (IGT) both preconceptionally and during gestation, and from C57BL/6N (B6) mice, which acquire this IGT only during gestation. Since substrain(s) of the NZO mice are known to show a variant in the Abcc8 gene, we additionally examined preconceptional SUR1 knock-out (SUR1-KO) mice. PyCreas provided quantitative evidence that alterations in the Abcc8 gene are associated with an altered distribution pattern of islet cells. Moreover, our data indicate that this cannot be a consequence of prolonged hyperglycemia, as islet architecture is already altered in the prediabetic state. Furthermore, the quantitative analysis suggests that states of transient IGT, such as during common gestational diabetes mellitus (GDM), are not associated with changes in islet architecture as observed during long-term IGT. PyCreas provides the ability to systematically analyze the localization and distribution of islet cells at different stages of metabolic disease to better understand the underlying pathophysiology.

839 A Retrospective, Multi-National, Longitudinal Study for Quantitative Analysis of Gender Distribution of Speakers at Major Neurosurgical Conferences

Abstract Aim To explore gender distribution of invited lecturers and panel speakers at major international neurosurgical conferences and investigate this as a potential contributor to lack of female representation in neurosurgery, known as a significant workforce problem, worldwide. Method We retrospectively analysed annual meetings organised by 4 major neurosurgical organisations between January 2016 and December 2021. Male and female faculty were academically stratified according to mean publications, citations, and H-index. A manel was defined as a session with 2 or more speakers, all of whom are men. Sex was determined by specific speaker title in conference program, online autobiography, or Gender Balance Assessment Tool (GBAT). Results Of the 21 conferences hosted by 4 major international neurosurgical societies/organisations analysed there were 5883 speakers, of which 10.93% (n = 643) were female. Of 885 panel sessions, 534 (60.34%) were manels. There were statistically significant changes between online and in-person conferences (45.45% (n = 60) manels online vs 62.95% (n = 474) manels in-person; p<0.05). Male invited lecturers had significantly higher mean H-index than female invited lecturers (male = 34.88, female = 18.95; p<0.05). There was a significant reduction in the proportion of manels over time (67.35% in 2016 vs 39.83% in 2021; p<0.05). Conclusions Despite encouraging findings that manels are becoming less prevalent in major neurosurgical meetings, they continue to comprise the majority, while female representation remains poor. This study hopes to highlight the need for greater gender diversity and female representation in neurosurgery.

1278 MANELS: A Retrospective, Multi-National, Longitudinal Study for Quantitative Analysis of Gender Distribution in Speakers at Major Pan-Specialty Surgical Conferences

Abstract Aim Although the proportion of female medical students worldwide is increasing, only an estimated 35% of UK surgical trainees are female, and only 14% of consultant surgeons – these statistics are similar globally. This study aims to quantify the gender distribution in invited speakers and panellists at international pan-specialty surgical conferences in recent years. Method Retrospective analysis of annual meetings organised by 5 international surgical organizations between January 2016 and December 2021 was conducted. Male and female faculty were academically stratified according to mean publications, citations, and H-index. A manel was defined as a session with ≥ 2 speakers, all of whom are men. Sex was determined by specific speaker title in conference program, online autobiography, or Gender Balance Assessment Tool (GBAT). Results Between 22 conferences, there were 1978 invited speakers, of which 25.6% (n = 506) were female. Of the included 74 panel sessions, 48.6% (n = 36) were manels. When considering the gender of invited lecture speakers, there was no significant difference in their mean H-indices (M = 33.4, F = 27.8, p = 0.063) or mean total publications (M = 205.6, F = 169.9). Male invited lecturers had a significantly higher number of citations (M = 7944.7, F = 4211.7, p = 0.025). There was a significant decrease in the proportion of manels between 2016 and 2021 (p = 0.01). Conclusions Despite the increasing representation of women in surgery, only one quarter of invited speakers were female and almost half of panels with two or more speakers were manels despite no difference in speaker H-index or publications. This study highlights the need for new strategies and concerted efforts to increase female representation at surgical conferences.

Core-Shell Au@Nanoplastics as a Quantitative Tracer to Investigate the Bioaccumulation of Nanoplastics in Freshwater Ecosystems.

Studies on the adverse effects of nanoplastics (NPs, particle diameter <1000 nm) including physical damage, oxidative stress, impaired cell signaling, altered metabolism, developmental defects, and possible genetic damage have intensified in recent years. However, the analytical detection of NPs is still a bottleneck. To overcome this bottleneck and obtain a reliable and quantitative distribution analysis in complex freshwater ecosystems, an easily applicable NP tracer to simulate their fate and behavior is needed. Here, size- and surface charge-tunable core-shell Au@Nanoplastics (Au@NPs) were synthesized to study the environmental fate of NPs in an artificial freshwater system. The Au core enables the quantitative detection of NPs, while the polystyrene shell exhibits NP properties. The Au@NPs showed excellent resistance to environmental factors (e.g., 1% hydrogen peroxide solution, simulating gastric fluid, acids, and alkalis) and high recovery rates (>80%) from seawater, lake water, sewage, waste sludge, soil, and sediment. Both positively and negatively charged NPs significantly inhibited the growth of duckweed (Lemna minor L.) but had little effect on the growth of cyanobacteria (Microcystis aeruginosa). In addition, the accumulation of positively and negatively charged NPs in cyanobacteria occurred in a concentration-dependent manner, with positively charged NPs more easily taken up by cyanobacteria. In contrast, negatively charged NPs were more readily internalized in duckweed. This study developed a model using a core-shell Au@NP tracer to study the environmental fate and behavior of NPs in various complex environmental systems.

Rotational Distributions and Imaging of Singlet O2 Following Spin-Forbidden Photodissociation of O3.

We report REMPI spectra and velocity-mapped ion images of the O2(a1Δg) and (b1Σg+) fragments arising from the spin-forbidden photodissociation of O3 near 320 and 330 nm. The O2(a1Δg, v = 0) REMPI spectrum following a 320 nm dissociation shows enhanced peak intensity for the odd rotational states relative to the even states, which is the opposite of the trend observed by Gunthardt et al. ( J. Chem. Phys. 2019, 151, 224302) for spin-allowed dissociation at 266 nm but is consistent with the couplings between the B state and 3A' and 3A″ states calculated by Grebenshchikov and Rosenwaks ( J. Phys. Chem. A 2010, 114, 9809-9819). There are no significant differences between the ion image angular distributions of fragments in odd and even rotational states, which indicates a cold distribution of O3 and supports the explanation that the alternation in peak intensities results from a difference in the couplings. Quantitative analysis of the image angular distributions was limited due to the single laser polarization geometry accessible in one-color experiments. Radial distributions of the 320 nm images indicate a broad rotational distribution, evidenced in bimodal speed distributions with peaks corresponding to both high (j = 35-43) and low (j = 17-20) rotational states. The REMPI spectrum of O2(a1Δg) near 330 nm was collected, and while quantitative population analysis is difficult because of the perturbed resonant state, the spectrum clearly supports a broad rotational distribution as well, consistent with the images collected at 320 nm. A 2D-REMPI spectrum was collected following dissociation of O3 near 330 nm, which showed evidence of contributions from O2 fragments in both the a1Δg and b1Σg+ states. The rotational distribution for the O2(b1Σg+, v = 0) product peaks at j = 32 and is narrower than that of the O2(a1Δg) fragment, consistent with distributions reported by O'Keeffe et al. at longer dissociation wavelengths ( J. Chem. Phys. 2002, 117, 8705-8709). At smaller radii in the 2D-REMPI spectrum, there is additional signal assigned to v = 1-4 of O2(b1Σg+), with rotational distributions similar to v = 0. The vibrational distribution of the O2(b1Σg+) fragment peaks at v = 0, with populations monotonically decreasing with increasing vibrational state. Ion image angular distributions of the O2(b1Σg+) fragment and the corresponding anisotropy parameters are also reported.

Three-Dimensional Imaging and Quantitative Analysis of Blood Vessel Distribution in The Meniscus of Transgenic Mouse after Tissue Clearing.

Blood supply to the meniscus determines its recovery and is a reference for treatment planning. This study aimed to apply tissue clearing and three-dimensional (3D) imaging in exploring the quantitative distribution of blood vessels in the mouse meniscus. In this experimental study, tissue clearing was performed to treat the bilateral knee joints of transgenic mice with fluorescent vascular endothelial cells. Images were acquired using a light sheet microscope and the vascular endothelial cells in the meniscus was analysed using 3D imaging. Quantitative methods were employed to further analyse the blood vessel distribution in the mouse meniscus. The traditional three-equal-width division of the meniscus is as follows: the outer one-third is the red-red zone (RR), the inner one-third is the white-white zone (WW), and the transition area is the red-white zone (RW). The division revealed significant signal differences between the RW and WW (P<0.05) zones, but no significant differences between the RR and RW zones, which indicated that the division might not accurately reflect the blood supply of the meniscus. According to the modified division (4:2:1) in which significant differences were ensured between the adjacent zones, we observed that the width ratio of each zone was 38 ± 1% (RR), 24 ± 1% (RW), and 38 ± 2% (WW). Furthermore, the blood supply to each region was verified. The anterior region had the most abundant blood supply. The fluorescence count in the anterior region was significantly higher than in the central and posterior regions (P<0.05). The blood supply of the medial meniscus was superior to the lateral meniscus (P<0.05). Analysis of the blood supply to the mouse meniscus under tissue clearing and 3D imaging reflect quantitative blood vessel distribution, which would facilitate future evaluations of the human meniscus and provide more anatomical references for clinicians.

A corpus-based study of the discourse functions of English tense: the co-occurrence of tense and lexical aspect at various textual positions of news reports

This study analyses the discourse functions of tense in the New York Times Corpus under a three-dimensional framework – the three dimensions being tense, verb and textual position. The texts are divided into ten 10 percent sub-sections and the distribution of the tenses along textual positions, the distribution of verb categories along textual positions as well as the distribution of tense-verb construction along textual positions are calculated to examine the features of tense use in news reports. The association between tense and verb categories is calculated using WordSmith log-likelihood statistics. Quantitative distribution analysis of the tenses reveals their distribution patterns. The distribution of the present and the present perfect follows a multi-peaked curve while there is a steady increase of preterit from the beginning to the end. The association between tense and verb shows that different tenses have attractions for different verb categories. The present tense attracts state verbs, the past tense attracts achievement verbs, and the present perfect prefers achievement and activity verbs. Analysis of tense-verb constructions along textual positions reveals that tense-verb constructions have localised functions – within different textual positions, tense-verb constructions take on various features and focus on different functions. All these findings constitute the stylistic use of tenses in news reports and reveal modern news values in the journalistic community.

Qualitative and Quantitative Analyses of the Enantiomers of Nicotine and Nornicotine Employing Chiral Supercritical Fluid Chromatography.

An optimized method employing chiral supercritical fluid chromatography with diode array UV-VIS detection has been developed for the quantitative analysis of nicotine and nornicotine enantiomer distributions. The method parameters that were optimized included: column type (stationary phases, Chiralpak IG-3), column temperature (40°C), modifier types and concentration (isopropyl alcohol, 10%), additive types and concentrations (diethylamine, 0.2%), elution times (<6min, flow rate 3mL/min) and resolution factor (>1.2). These optimized conditions led to nicotine and nornicotine enantiomer detection limits of ~5ng/μL with accompanying %RSD values of <2% from the analyses of commercially available nicotine-containing formulations.

Optimal slice thickness for improved accuracy of quantitative analysis of fluorescent cell and microsphere distribution in cryo-images

Cryo-imaging has been effectively used to study the biodistribution of fluorescent cells or microspheres in animal models. Sequential slice-by-slice fluorescent imaging enables detection of fluorescent cells or microspheres for corresponding quantification of their distribution in tissue. However, if slices are too thin, there will be data overload and excessive scan times. If slices are too thick, then cells can be missed. In this study, we developed a model for detection of fluorescent cells or microspheres to aid optimal slice thickness determination. Key factors include: section thickness (X), fluorescent cell intensity (Ifluo), effective tissue attenuation coefficient (μT), and a detection threshold (T). The model suggests an optimal slice thickness value that provides near-ideal sensitivity while minimizing scan time. The model also suggests a correction method to compensate for missed cells in the case that image data were acquired with overly large slice thickness. This approach allows cryo-imaging operators to use larger slice thickness to expedite the scan time without significant loss of cell count. We validated the model using real data from two independent studies: fluorescent microspheres in a pig heart and fluorescently labeled stem cells in a mouse model. Results show that slice thickness and detection sensitivity relationships from simulations and real data were well-matched with 99% correlation and 2% root-mean-square (RMS) error. We also discussed the detection characteristics in situations where key assumptions of the model were not met such as fluorescence intensity variation and spatial distribution. Finally, we show that with proper settings, cryo-imaging can provide accurate quantification of the fluorescent cell biodistribution with remarkably high recovery ratios (number of detections/delivery). As cryo-imaging technology has been used in many biological applications, our optimal slice thickness determination and data correction methods can play a crucial role in further advancing its usability and reliability.

Atomistic modelling and structural characterisation of coated gold nanoparticles for biomedical applications

This study presents the results of atomistic structural characterisation of 3.7-nm-diameter gold nanoparticles (NP) coated with polymer polyethylene glycol-based ligands of different lengths (containing 2–14 monomers) and solvated in water. The system size and composition are selected in connection to several experimental studies of radiosensitisation mechanisms of gold NPs. The coating structure and water distribution near the NP surface are characterised on the atomistic level by means of molecular dynamics simulations. The results of simulations carried out in this study, combined with the results of our recent study (Verkhovtsev et al. in J Phys Chem A 126:2170–2184, 2022) and those from the field of polymer physics, are used to calculate key structural parameters of the coatings of radiosensitising gold NPs. On this basis, connections between the coating structure and distribution of water are established for different NP sizes as well as lengths and surface densities of coating molecules. The quantitative analysis of water distribution in the vicinity of coated metal NPs can be used to evaluate the radiosensitising effectiveness of a particular NP system based on the proximity of water to the NP metal core, which should impact the production of hydroxyl radicals and reactive oxygen species in the vicinity of metal NPs exposed to ionising radiation.Graphical abstract

Analysis Method of Full-Scale Pore Distribution Based on MICP, CT Scanning, NMR, and Cast Thin Section Imaging—A Case Study of Paleogene Sandstone in Xihu Sag, East China Sea Basin

Using different experimental methods, the pore radius ranges vary greatly, and most scholars use a single experiment to study pore structure, which is rarely consistent with reality. Moreover, the numerical models used in different experiments vary and cannot be directly compared. This article uniformly revised all experimental data into a cylinder model. Quantitative analysis of the full-scale pore distribution is established by mercury withdrawal–CT data, and semi-quantitative distribution is obtained by mercury–NMR–cast thin section imaging. In this paper, we introduce the tortuosity index (τ) to convert the CT ball-and-stick model into a cylinder model, and the pore shape factor (η) of the cast is used to convert the plane model into the cylinder model; the mercury withdrawal data is applied to void the influence of narrow throat cavities, and the NMR pore radius distribution is obtained using the mercury-T2 calibration method. Studies have shown that the thickness of bound water is 0.35~0.4 μm, so the pores with different radius ranges were controlled by different mechanisms in the NMR tests, with pores &lt; 0.35~0.4 μm completely controlled by surface relaxation, including strong bound water and weak bound water; pores in the 0.4~4 μm reange were controlled by surface relaxation; and pores &gt; 10 μm were completely controlled by free relaxation. The surface relaxivity rate of fine sandstone was 18~20 μm/s. The tortuosity index τ was generally 1~7; the larger the value, the more irregular the pores. The pore shape factor η was generally 0.2~0.5; the smaller the value, the more irregular the pores. Mercury withdrawal–CT scan data can quantitatively determine the pore radius distribution curve. The coefficient of the logarithm is positive considering porosity, and the constant is negative considering porosity. Permeability controls the maximum pore radius, with a max pore radius &gt; 100 μm and a permeability &gt; 1 mD. Mercury withdrawal–NMR–cast thin section imaging data can semi-quantitatively establish a pore radius distribution histogram. The histogram represents quasi-normal, stepped, and unimodal data. When 60 μm is the inflection point, if a large proportion of pores measure &gt; 60 μm, good reservoir quality is indicated. If a large proportion of pores measures &lt; 60 μm, the permeability is generally &lt;0.5 mD.

Quantitative elemental imaging in eukaryotic algae.

All organisms, fundamentally, are made from the same raw material, namely the elements of the periodic table. Biochemical diversity is achieved by how these elements are utilized, for what purpose, and in which physical location. Determining elemental distributions, especially those of trace elements that facilitate metabolism as cofactors in the active centers of essential enzymes, can determine the state of metabolism, the nutritional status, or the developmental stage of an organism. Photosynthetic eukaryotes, especially algae, are excellent subjects for quantitative analysis of elemental distribution. These microbes utilize unique metabolic pathways that require various trace nutrients at their core to enable their operation. Photosynthetic microbes also have important environmental roles as primary producers in habitats with limited nutrient supplies or toxin contaminations. Accordingly, photosynthetic eukaryotes are of great interest for biotechnological exploitation, carbon sequestration, and bioremediation, with many of the applications involving various trace elements and consequently affecting their quota and intracellular distribution. A number of diverse applications were developed for elemental imaging, allowing subcellular resolution, with X-ray fluorescence microscopy (XFM, XRF) being at the forefront, enabling quantitative descriptions of intact cells in a non-destructive method. This Tutorial Review summarizes the workflow of a quantitative, single-cell elemental distribution analysis of a eukaryotic alga using XFM.

A new visual approach with the concentration calibration method for the hydrogen leakage and distribution research

Hydrogen security is an intrinsic requirement for the increasing development of hydrogen energy. The evolutional regularity of hydrogen leakage including hydrogen concentration and its distribution plays a key role in hydrogen leakage prevention, hence essential for safety research. It is difficult to measure hydrogen concentration distribution covering the whole area as a measurement plane due to the discreteness or invasiveness of the conventional sensing method. To solve the problem, this paper proposed a new method for quantitative analysis of hydrogen leakage distribution with a visual imaging experiment. Firstly, a series of imaging experiments under different leakage concentrations were performed based on the schlieren technique. A new calibration method is developed to deal with the mapping relationship between the jet leakage concentration and the gray value of the schlieren image. Therefore, the different gray values of the schlieren image are labeled as different hydrogen concentrations. Then, by extracting the quantitative concentration information in the axial and radial direction of the schlieren image, the concentration attenuation formulas in these two directions can be obtained. The proposed visual approach together with the gray calibration method are verified by comparative experiments, and the attenuation formula accurately represents the jet concentration distribution with an average error of less than 10%.

Laser scattering centrifugal liquid sedimentation method for the accurate quantitative analysis of mass-based size distributions of colloidal silica.

This paper proposes a laser scattering centrifugal liquid sedimentation (LS-CLS) method for the accurate quantitative analysis of the mass-based size distributions of colloidal silica. The optics comprised a laser diode light source and multi-pixel photon-counting detector for detecting scattered light intensity. The unique optics can only detect the light scattered by a sample through the interception of irradiated light. The developed centrifugal liquid sedimentation (CLS) method comprised a light-emitting diode and silicon photodiode detector for detecting transmittance light attenuation. The CLS apparatus could not accurately measure quantitative volume- or mass-based size distribution of poly-dispersed suspensions, such as colloidal silica, because the detecting signal includes both transmitted and scattered light. The LS-CLS method exhibited improved quantitative performance. Moreover, the LS-CLS system allowed the injection of samples with concentrations higher than that permitted by other particle size distribution measurement systems with particle size classification units using size-exclusion chromatography or centrifugal field-flow fractionation. The proposed LS-CLS method achieved an accurate quantitative analysis of the mass-based size distribution using both centrifugal classification and laser scattering optics. In particular, the system could measure the mass-based size distribution of approximately 20mgmL-1 poly-dispersed colloidal silica samples, such as in a mixture of the four mono-dispersed colloidal silica, with high resolution and precision, thereby demonstrating high quantitative performance. The measured size distributions were compared with those observed through transmission electron microscopy. The proposed system can be used in practical setups to achieve a reasonable degree of consistency for determining particle size distribution in industrial applications.