Macroscopic Changes Research Articles

(Invited) Multimodal Operando Studies of Dynamic Cu Nanocatalysts for CO2 Electroreduction

In an era of shifting the energy paradigm from fossil fuels to renewable energy, CO2 reduction reaction (CO2RR) emerges as a promising approach to covert greenhouse gas into valuable chemical fuels and close the carbon cycle for a sustainable energy supply. Since Cu remains the sole element for CO2RR to multicarbon products (C2+), significant efforts have been devoted to developing Cu electrocatalysts with higher selectivity and activity. However, the complex nature of active sites and the intrinsic structures under reaction conditions have remained largely elusive due to the lack of operando/in situ methods.1-3 In our previous studies, we reported that small Cu nanoparticles (sub-10 nm NPs) showed superior C2+ superior C2+ selectivity, relative to the larger sized Cu NPs, especially at low overpotentials.4,5 In this work, we present a comprehensive operando correlative study of dynamic evolution during the life cycle of a family of monodisperse Cu NP ensemble electrocatalysts under CO2RR.1 Operando electrochemical liquid-cell scanning transmission electron microscopy (EC-STEM) and 4D-STEM resolves microscopic dynamic morphological and structural evolution at the nm scale. Correlated operando high-energy-resolution fluorescence-detector (HERFD) X-ray absorption spectroscopy (XAS)6 reveals dynamic macroscopic changes in valence states and coordination environment. Statistical analysis of interparticle dynamics was probed by operando resonant soft X-ray-based small-angle X-ray scattering (SAXS).2 The operando correlative strategies, described herein, elucidates the longstanding enigmatic nature of Cu active sites as metallic Cu nanograins for selective CO2 electroreduction (Fig. 1). The strategy described herein can serve as a general platform to resolve the electrocatalytic interface of nanoparticle catalysts under real-time operating conditions across multiple time and length scales, thus serving the fundamental understanding necessary to development of many other electrochemical reactions for renewable energy technologies.

Cardiac alterations induced by Heloderma horridum horridum venom in rats: An experimental study with ECG analysis using a linear regression algorithm

Envenomation by reptile venom, particularly from lizards, poses significant health risks and can lead to physiological and cardiovascular changes. The venom of Heloderma horridum horridum, endemic to Colima, Mexico, was tested on Wistar rats. Electrocardiographic (ECG) data were collected pre-treatment and at 5-min intervals for 1 h post-envenomation. A specially designed computational linear regression algorithm (LRA) was used for the segmentation analysis of the ECG data to improve the detection of fiducial points (P, Q, R, S, and T) in ECG waves. Additionally, heart tissue was analyzed for macroscopic and microscopic changes. The results revealed significant electrocardiographic alterations, including pacemaker migration, junctional extrasystoles, and intraventricular conduction aberrations. By applying a linear regression algorithm, the study compensated for noise and anomalies in the isoelectric line in an ECG signal, improving the detection of P and T waves and the QRS complex with an efficiency of 97.5%. Cardiac enzyme evaluation indicated no statistically significant differences between the control and experimental groups. Macroscopic and microscopic examination revealed no apparent signs of damage or inflammatory responses in heart tissues. This study enhances our understanding of the cardiovascular impact of Heloderma venom, suggesting a greater influence on changes in conduction and arrhythmias than on direct cardiac damage to the myocardium.

NOVEL METHODOLOGY FOR DEVELOPING A MACHINE LEARNING-BASED IMAGING TOOL FOR HYBRID VISUALIZATION OF MACROSCOPIC AND MICROSCOPIC DEGENERATIVE CHANGES IN THE INTERVERTEBRAL DISC

BackgroundMagnetic resonance imaging (MRI) algorithm identifies end stage severely degenerated disc as ‘black’, and a moderately degenerate to non-degenerated disc as ‘white’. MRI is based on signal intensity changes that identifies loss of proteoglycans, water, and general radial bulging but lacks association with microscopic features such as fissure, endplate damage, persistent inflammatory catabolism that facilitates proteoglycan loss leading to ultimate collapse of annulus with neo-innervation and vascularization, as an indicator of pain. Thus, we propose a novel machine learning based imaging tool that combines quantifiable microscopic histopathological features with macroscopic signal intensities changes for hybrid assessment of disc degeneration.Methods100-disc tissue were collected from patients undergoing surgeries and cadaveric controls, age range of 35–75 years. MRI Pfirrmann grades were collected in each case, and each disc specimen were processed to identify the 1) region of interest 2) analytical imaging vector 3) data assimilation, grading and scoring pattern 4) identification of machine learning algorithm 5) predictive learning parameters to form an interface between hardware and software operating system.ResultsKernel algorithm defines non-linear data in xy histogram. X,Y values are scored histological spatial variables that signifies loss of proteoglycans, blood vessels ingrowth, and occurrence of tears or fissures in the inner and outer annulus regions mapped with the dampening and graded series of signal intensity changes.ConclusionTo our knowledge this study is the first to propose a machine learning method between microscopic spatial tissue changes and macroscopic signal intensity grades in the intervertebral disc.No conflict of interest declared. Sources of FundingICMR/5/4-5/3/42/Neuro/2022-NCD-1, Dr TMA PAI SMU/ 131/ REG/ TMA PURK/ 164/2020.A part of the above study was presented as an oral paper at the International Society for the Study of Lumbar Spine (ISSLS) meeting held on 1–5th May 2023, Melbourne, Australia.

The thermal stability mechanism of MBA-crosslinked PPGs: Insights from macroscopic phenomena to chemical reactions

Preformed particle gels (PPGs) is one of the most efficient enhanced oil recovery techniques used for conformance control. Evaluating the thermal stability of PPGs and understanding their thermal stability mechanism are crucial for the development and application of high-temperature-resistant PPGs. We focused on conventional N, N′-methylene-bis-acrylamide (MBA) crosslinked PPGs, systematically analyzing the macroscopic state changes, microstructural changes, and chemical reactions occurring during the ageing process in 1 % NaCl solution at different temperatures, and delved into their thermal stability mechanism. Our findings revealed that the swelling ratio (SR) of PPGs during ageing is correlated with temperature, showing three distinct patterns: a stable SR at low temperatures (<60 °C), a period of unchanged swelling followed by a continuous increase within the intermediate temperature range (70–90 °C), and a rapid swelling leading to sol conversion at high temperatures (>95 °C). Scanning electron microscope observations and elastic modulus analysis confirmed that the microstructure of PPGs remains stable when the SR was unchanged, while continuous increases in the SR indicated damage to the gel's micro-network structure. X-ray photoelectron spectrum and carbon nuclear magnetic resonance spectroscopy indicated that no chemical reactions occurred in PPGs at temperatures not exceeding 60 °C. When temperature was 70–100 °C, a small amount of acrylamide (AM) hydrolysis occurred initially, which then sequentially triggered the hydrolysis of MBA crosslinkers and 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) due to the catalytic effect of undissociated carboxyl. At temperatures above 100 °C, hydrolysis reactions occurred simultaneously in AM, MBA crosslinkers, and AMPS. The thermal stability of MBA-crosslinked PPGs is indeed related to the thermal stability of the MBA, but it can be reduced by the influence of other non-temperature-resistant monomers, such as AM. This study provides insights into the thermal stability mechanisms of PPGs and guidance for the development of high-temperature-resistant PPGs.

Arylazo-3,5-diphenylpyrazole Derivatives: Molecular Probes Exhibiting Reversible Light-induced Phase Transitions for Energy Storage and Direct Photolithographic Patterning.

We report azopyrazole photoswitches decorated with variable N-alkyl and alkoxy chains (for hydrophobic interactions) and phenyl substituents on the pyrazoles (enabling π-π stacking), showing efficient bidirectional photoswitching and reversible light-induced phase transition (LIPT). Extensive spectroscopic, microscopic, and diffraction studies and computations confirmed the manifestation of molecular-level interactions and photoisomerization into macroscopic changes leading to the LIPT phenomena. Using differential scanning calorimetric (DSC) studies, the energetics associated with those accompanying processes were estimated. The long half-lives of Z isomers, high energy contents for isomerization and phase transitions, and the stability of phases over an extended temperature range (-60 to 80 °C) make them excellent candidates for energy storage and release applications. Remarkably, the difference in the solubility of the distinct phases in one of the derivatives allowed us to utilize it as a photoresist in photolithography applications on diverse substrates.

Macroscopic and Histological Effects of Polycaprolactone Dermal Filler in the Orofacial Region: A Study in Rats

The objective of our study was to evaluate early and late macroscopic and histological changes associated with the use of polycaprolactone dermal filler (PCL) in the orofacial region. Forty-eight female Wistar rats were divided into the PCL group and the control group. The material was applied to the ventral tongue and submandibular region, and the animals were euthanized at three time points—24 h, and 30 and 90 days. In the PCL group, yellowish nodules were observed on the tongue at all experimental time points. At the 24 h mark, the histological analysis revealed the presence of the PCL and a predominance of lymphocytes, plasma cells, and neutrophils. At 30 and 90 days, macrophages and multinucleated giant cells predominated around the PCL spheres. Collagen density in the dermis was higher in the PCL group when compared to the control at 30 and 90 days. In the submandibular glands, an inflammatory process similar to that observed at other sites was noted, with no alterations in acinar or ductal morphology. The results of this study highlight the effectiveness of PCL as a collagen biostimulator. Nevertheless, the development of nodular lesions on the tongue signals the potential risk of complications in mobile anatomical structures.

Water and brain function: effects of hydration status on neurostimulation with transcranial magnetic stimulation.

Neurostimulation/neurorecording are tools to study, diagnose, and treat neurological/psychiatric conditions. Both techniques depend on volume conduction between scalp and excitable brain tissue. Here, we examine how neurostimulation with transcranial magnetic stimulation (TMS) is affected by hydration status, a physiological variable that can influence the volume of fluid spaces/cells, excitability, and cellular/global brain functioning. Normal healthy adult participants (32, 9 males) had common motor TMS measures taken in a repeated-measures design from dehydrated (12-h overnight fast/thirst) and rehydrated (identical dehydration protocol followed by rehydration with 1 L water in 1 h) testing days. The target region was left primary motor cortex hand area. Response at the target muscle was recorded with electromyography. Urinalysis confirmed hydration status. Motor hotspot shifted in half of participants. Motor threshold decreased in rehydration, indicating increased excitability. Even after redosing/relocalizing TMS to the new threshold/hotspot, rehydration still showed evidence of increased excitability: recruitment curve measures generally shifted upward and the glutamate-dependent paired-pulse protocol, short intracortical facilitation (SICF), was increased. Short intracortical inhibition (SICI), long intracortical inhibition (LICI), long intracortical facilitation (LICF), and cortical silent period (CSP) were relatively unaffected. The hydration perturbations were mild/subclinical based on the magnitude/speed and urinalysis. Motor TMS measures showed evidence of expected physiological changes of osmotic challenges. Rehydration showed signs of macroscopic and microscopic volume changes including decreased scalp-cortex distance (brain closer to stimulator) and astrocyte swelling-induced glutamate release. Hydration may be a source of variability affecting any techniques dependent on brain volumes/volume conduction. These concepts are important for researchers/clinicians using such techniques or dealing with the wide variety of disease processes involving water balance.NEW & NOTEWORTHY Hydration status can affect brain volumes and excitability, which should affect techniques dependent on electrical volume conduction, including neurostimulation/recording. We test the previously unknown effects of hydration on neurostimulation with TMS and briefly review relevant physiology of hydration. Rehydration showed lower motor threshold, shifted motor hotspot, and generally larger responses even after compensating for threshold/hotspot changes. This is important for clinical and research applications of neurostimulation/neurorecording and the many clinical disorders related to water balance.

Superior performance of hierarchical 3D microflower CuS grown on carbon cloth as binder free electrode for supercapacitor applications

Copper sulfide (CuS) was grown on the carbon cloth (CC) utilizing the traditional hydrothermal method. The role of different reaction time of 5 h, 10 h, and 15 h (C15) were investigated with fixed reaction time of 150 °C. XRD confirmed the growth of pure CuS on CC. Macroscopic changes in morphology were observed with increasing the reaction time and C15 showed ∼3.08 μm diameter of CuS microflowers with ∼ 34.68 nm thickness of nanosheets embedded in the microflowers. C15 showed a lowest bandgap of 1.8 eV with high copper content of 34 % and the copper content increases fast electron movement and maintains structural stability. The supercapacitor behavior was investigated in 1 M Mg(NO3)2 aqueous electrolyte and C15 demonstrated the highest specific capacitance of 83.70 F/g at 5 mV/s. An aqueous symmetric electrode made with C15 displays 149 F/g specific capacitance and 87.2 % retention at 1 A/g for 1000 cycles.

Deformation-based morphometry: a sensitive imaging approach to detect radiation-induced brain injury?

BackgroundRadiotherapy is a major therapeutic approach in patients with brain tumors. However, it leads to cognitive impairments. To improve the management of radiation-induced brain sequalae, deformation-based morphometry (DBM) could be relevant. Here, we analyzed the significance of DBM using Jacobian determinants (JD) obtained by non-linear registration of MRI images to detect local vulnerability of healthy cerebral tissue in an animal model of brain irradiation.MethodsRats were exposed to fractionated whole-brain irradiation (WBI, 30 Gy). A multiparametric MRI (anatomical, diffusion and vascular) study was conducted longitudinally from 1 month up to 6 months after WBI. From the registration of MRI images, macroscopic changes were analyzed by DBM and microscopic changes at the cellular and vascular levels were evaluated by quantification of cerebral blood volume (CBV) and diffusion metrics including mean diffusivity (MD). Voxel-wise comparisons were performed on the entire brain and in specific brain areas identified by DBM. Immunohistology analyses were undertaken to visualize the vessels and astrocytes.ResultsDBM analysis evidenced time-course of local macrostructural changes; some of which were transient and some were long lasting after WBI. DBM revealed two vulnerable brain areas, namely the corpus callosum and the cortex. DBM changes were spatially associated to microstructural alterations as revealed by both diffusion metrics and CBV changes, and confirmed by immunohistology analyses. Finally, matrix correlations demonstrated correlations between JD/MD in the early phase after WBI and JD/CBV in the late phase both in the corpus callosum and the cortex.ConclusionsBrain irradiation induces local macrostructural changes detected by DBM which could be relevant to identify brain structures prone to radiation-induced tissue changes. The translation of these data in patients could represent an added value in imaging studies on brain radiotoxicity.

Dynamic stress characterization and instability risk identification using multisource acoustic signals in cut-and-fill stopes

The quantitative characterization of rock mass and stress changes induced by mining activities is crucial for structural stability monitoring and disaster early warning. This paper investigates the time–space–intensity distribution of microseismic sources during the pillar-free large-area continuous extraction. Furthermore, it explores a method involving collaborative evolution patterns of the velocity field and spatial b-value to identify stress and structural changes at the panel stope. Results show that anomalous zones in wave velocities and b-values form at the intersections of extraction drifts, strike drifts, cross drifts, and connection roadways influenced by mining activities, as well as in footwall ore-rock contacts, often accompanied by the nucleation of microseismic events. The synergistic use of wave velocity fields and spatial b-value models reveals the relationship between stress migration behavior and stope structure changes due to mining disturbances. The velocity field primarily reflects macroscopic changes in the structure and stress distribution, while spatial b-values further explain stress gradients in specific areas. Additionally, we have advanced the identification of an instability disaster at the connection roadway and cross drift intersection based on increases in wave velocity and abnormal changes in b-value. This paper demonstrates the potential of risk identification using the proposed method, providing insights into predicting geotechnical engineering disasters in complex stress environments.

Exploring pNIPAM lyogels: Experimental study on swelling equilibria in various organic solvents and mixtures, supported by COSMO-RS analysis

Stimuli-responsive lyogels are considered to be smart materials due to their capability of undergoing significant macroscopic changes in response to external triggers. Due to their versatile and unique properties, smart lyogels exhibit great potential in various applications such as drug delivery or actuation processes. While Poly-N-isopropylacrylamide (pNIPAM) is widely known as a thermo-responsive material, it also shows significant solvent-responsive swelling behavior. For the systems tested, polar solvents induce strong swelling due to hydrogen bonding with the amide group, nonpolar solvents lead to significant shrinkage of the lyogels. The aim of this study is to investigate and to model this behavior for future application in chemical or biochemical reactors. As a current area of research, incorporating smart lyogel technology into (bio-)chemical reactors facilitates the development of smart reactor systems. Applying thermodynamic modelling with the gE model COSMO-RS on the monomer or oligomers of pNIPAM, the correlation between solvent-polymer interactions and the degree of swelling can be observed. pNIPAM derivatives exhibit low infinite dilution activity coefficients (IDACs) in polar solvents with large degrees of swelling, while displaying an increase of IDACs in nonpolar solvents. Hydrogen bonds dominate the swelling behavior of lyogels not only in pure solvents but also in mixtures of solvents with varying polarity. Even in mixtures containing high amounts of nonpolar solvents, large degrees of swelling were observed due to the uptake of the polar solvent in the lyogel matrix. This effect can be observed in binary solvent mixtures but also in representative mixtures along an esterification reaction with varying carboxylic chain length of alcohol and carboxylic acids.

Unifying the temperature dependent dynamics of glass formers.

Strong changes in bulk properties, such as modulus and viscosity, are observed near the glass transition temperature, Tg, of amorphous materials. For more than a century, intense efforts have been made to define a microscopic origin for these macroscopic changes in properties. Using transition state theory (TST), we delve into the atomic/molecular level picture of how microscopic localized unit relaxations, or "cage rattles," evolve to macroscopic structural relaxations above Tg. Unit motion is broken down into two populations: (1) simultaneous rearrangement occurs among a critical number of units, nα, which ranges from 1 to 4, allowing a systematic classification of glass formers, GFs, that is compared to fragility; and (2) near Tg, adjacent units provide additional free volume for rearrangement, not simultaneously, but within the "primitive" lifetime, τ1, of one unit rattling in its cage. Relaxation maps illustrate how Johari-Goldstein β-relaxations stem from the rattle of nα units. We analyzed a wide variety of glassy materials and materials with a glassy response using literature data. Our four-parameter equation fits "strong" and "weak" GFs over the entire range of temperatures and also extends to other glassy systems, such as ion-transporting polymers and ferroelectric relaxors. The role of activation entropy in boosting preexponential factors to high "unphysical" apparent frequencies is discussed. Enthalpy-entropy compensation is clearly illustrated using the TST approach.

Enhancing the engineering performance of lightweight limestone calcined clay cement concrete using used engine oil as a foam stabilizer

Lightweight foam concrete is an appealing thermal insulation material with great potential for decarbonizing the building sector, given that its superior thermal insulation and reduced material usage promote energy-efficient and low-carbon constructions. However, traditional foam concrete largely depends on carbon-intensive ordinary Portland cement (OPC) and costly foam stabilizers, e.g., nanomaterials. To address these issues, this study developed an eco-friendly foam concrete formula incorporating limestone calcined clay cement as a low-carbon cement substitute and used engine oil (UEO) as a foam stabilizer. The viability of this formula was confirmed by assessing foam stability performance of UEO-enhanced foam and crucial engineering performance – thermal conductivity and compressive strength – of foam concrete. Experiments demonstrate that 1 % UEO notably boosts foam stability, with prolonged stable time by 75 % and enhanced remaining foam fraction by 43 %. Additionally, 1 % UEO-containing foam concrete exhibits superior compressive strength of 3.2 MPa and reduced thermal conductivity of 0.162 W⋅m-1K-1, outperforming foam concrete without UEO. The mechanisms of macroscopic performance changes were revealed through scanning electron microscopy (SEM), which disclosed a uniformly established UEO-enhanced pore system and UEO-driven hydration process as the microscale origins. These findings provide waste-enhanced foam stabilizers and present an environmentally appealing alternative to traditional foam concrete, with implications for clean waste management and building decarbonization.

Structure and dynamics of amphiphilic patchy cubes in a nanoslit under shear.

Patchy nanocubes are intriguing materials with simple shapes and space-filling and multidirectional bonding properties. Previous studies have revealed various mesoscopic structures such as colloidal crystals in the solid regime and rod-like or fractal-like aggregates in the liquid regime of the phase diagram. Recent studies have also shown that mesoscopic structural properties, such as an average cluster size M and orientational order, in amphiphilic nanocube suspensions are associated with macroscopic viscosity changes, mainly owing to differences in cluster shape among patch arrangements. Although many studies have been conducted on the self-assembled structures of nanocubes in bulk, little is known about their self-assembly in nanoscale spaces or structural changes under shear. In this study, we investigated mixtures of one- and two-patch amphiphilic nanocubes confined in two flat parallel plates at rest and under shear using molecular dynamics simulations coupled with multiparticle collision dynamics. We considered two different patch arrangements for the two-patch particles and two different slit widths H to determine the degree of confinement in constant volume fractions in the liquid regime of the phase diagram. We revealed two unique cluster morphologies that have not been previously observed under bulk conditions. At rest, the size of the rod-like aggregates increased with decreasing H, whereas that of the fractal-like aggregates remained constant. Under weak shear with strong confinement, the rod-like aggregates maintained a larger M than the fractal-like aggregates, which were more rigid and maintained a larger M than the rod-like aggregates under bulk conditions.

The role of upper gastrointestinal endoscopy in the diagnosis of pediatric inflammatory bowel disease.

Upper gastrointestinal (UGI) tract involvement is frequently reported in pediatric Crohn disease (CD) and ulcerative colitis (UC). Aside from granulomas, most findings are nonspecific. The aims of this study were to review the prevalence of UGI tract findings in pediatric patients with CD or UC at diagnosis and to describe differences in endoscopic and histologic features. Patients with CD and UC aged 2 to 17 years diagnosed between 2000 and 2015 who had upper and lower endoscopy at diagnosis were randomly chosen from the BC Children's Hospital inflammatory bowel disease (IBD) registry. Pathology review of the UGI biopsy specimens was blinded to IBD diagnosis. Of the 198 patients, 102 with CD and 96 with UC were included, with a mean age of 11.7 years (range, 2.3-17 years). Patients with CD were more likely to have aphthous ulcers (20.4% vs 3.5%, P = .002) and erosions (16.3% vs 3.5%, P =.018), most commonly affecting the antrum. Macroscopically normal UGI endoscopy was present in 60% of patients. Microscopic disease was reported in 100% of patients with CD and 87% of patients with UC. In both groups, nonspecific inflammation was the most common finding. Chronic deep, superficial, and diffuse inflammation were more frequent among patients with CD than UC (42% vs 4%, P < .001; 60% vs 17%, P < .001; 50% vs 34%, P = .04, respectively). The UGI tract macroscopic changes were common in pediatric IBD, especially in CD. Despite macroscopically normal endoscopy, histologic abnormalities were frequent. Although chronic inflammation was more often reported in patients with CD, aside from granulomas there were no unique histologic abnormalities unique to CD.

Macroscopic Differences of Pig Eye after Death: A Veterinary Forensic Study

The study of veterinary forensics is a field of science that is developing rapidly in the world of veterinary medicine. Veterinary forensics plays a crucial role in investigating and resolving cases involving animals, either as subjects or objects in incidents and ensuring the collection of all possible biological and physical evidence. Given the close relationship between humans and animals, numerous significant cases arise that are pertinent to veterinary forensics. The current research aimed to determine early post-mortem changes in pigs, providing insights into animal mortality in real-world scenarios. Observations were made on seven male Yorkshire pigs, aged 3 months old, with an average weight of 30.1 kg. Pigs were observed at four different post-mortem intervals, including 2,4,6, and 8 hours after death, with initial observations at the time of death serving as the control. Observations of changes in the eye sclera, eye lens, eyeball temperature, and eyeball pressure were carried out at each time interval. Results at the 2nd and 4th hours post-mortem showed no macroscopic changes in the eye sclera and eye lens, but there were changes in eye pressure. By the 6th and 8th hours, changes in the sclera and eye lens showed desiccation in the area of the sclera and the eye lens, which became increasingly cloudy. The eyeball temperature measurement values from the 2nd to 8th hour of the study revealed a significant decrease in eyeball pressure. The results of this study indicated observable changes in the eyes can be used as a basic alternative method for calculating the introductory post-mortem interval in animals in the future. There was a significant decrease in eyeball temperature, and eyeball compactness, as significant differences in the eye sclera, and eye lens at 2, 4, 6, and 8 hours post-mortem, compared to the time of death. These variables offer crucial insights into early post-mortem changes in pigs, using the eyes as the primary focus of observation.

Is It Safe to Operate without Frozen Section Biopsies in Short-Segment Hirschsprung's Disease? An Overview of 60 Cases.

Background: Advancements in surgical management in a single-stage procedure made intraoperative frozen section biopsies critical for determining of level of resection to avoid the potential risk of leaving a retained aganglionic segment. However, in most low-income countries, due to the lack of this facility, the surgeon's intraoperative judgment is used for the determination of the resection level. Objective: This study aims to evaluate the accuracy of determining the level of bowel resection in short-segment Hirschsprung's disease based on macroscopic changes. Materials and methods: Intraoperative macroscopic evaluations were assessed using postoperative microscopic findings to determine whether the surgeons' intraoperative judgments were accurate in determining the level of bowel resection in 60 cases of operated short-segment Hirschsprung's disease. In addition, Pearson's correlation coefficient was used to determine whether the sensitivity and specificity of both methods were significantly correlated. Results: The microscopic results showed that the level of resection based on the macroscopic evaluation was performed in normally ganglionated segment in cases of short-segment Hirschsprung's disease. Conclusions: Macroscopic intraoperative assessment by an experienced surgeon is highly accurate method of determining the level of bowel resection in short-segment HSCR.

Multiscale Dynamic Diffusion Model for Ions in Micro- and Nano-Porous Structures of Fly Ash: Mineralization Experimental Research

The leaching concentration of alkaline ions plays a crucial role in the efficiency of the CO2 mineralization reaction in fly ash. The multi-scale structural characteristics of micro–nano pores in fly ash are the primary factors that control the leaching and diffusion rate of alkaline ions. However, the existing theoretical models do not account for the multi-scale pore structure, leading to challenges in accurately describing the ion diffusion in fly ash and predicting the reaction rate and efficiency of CO2 mineralization. To address this issue, a multi-scale dynamic diffusion model of ions was developed based on the micro–nano pore structure of fly ash. This model established the relationship between the ionic leaching rate and pore structure, as well as macroscopic changes over time, which were validated through experiments. Mineralization experiments with varying soaking times and uniaxial compression experiments on mineralized specimens were conducted to investigate the relationships among soaking time, ion leaching concentration, mineralization degree, and mechanical strength. The results elucidated the impact of alkaline ion concentration on the mineralization degree and mechanical strength of fly ash materials, offering theoretical insights to enhance mineralization and material properties.

Surface-Grafted Single-Atomic Pt-Nx Complex with a Precisely Regulating Coordination Sphere for Efficient Electron Acceptor-Inducing Interfacial Electron Transfer.

Based on the electron-withdrawing effect of the Pt(bpy)Cl2 molecule, a simple post-modification amide reaction was firstly used to graft it onto the surface of NH2-MIL-125, which performed as a highly efficient electron acceptor that induced the conversion of the photoinduced charge migration pathway from internal BDC→TiOx migration to external BDC→PtNx migration, significantly improving the efficiency of photoinduced electron transfer and separation. Furthermore, precisely regulating over the first coordination sphere of Pt single atoms was achieved using further post-modification with additional bipyridine to investigate the effect of Pt-Nx coordination numbers on reaction activity. The as-synthesized NML-PtN2 exhibited superior photocatalytic hydrogen evolution activity of 7.608 mmol g-1 h-1, a remarkable improvement of 225 and 2.26 times compared to pristine NH2-MIL-125 and NML-PtN4, respectively. In addition, the superior apparent quantum yield of 4.01 % (390 nm) and turnover frequency of 190.3 h-1 (0.78 wt % Pt SA; 129 times compared to Pt nanoparticles/NML) revealed the high solar utilization efficiency and hydrogen evolution activity of the material. And macroscopic color changes caused by the transition of carrier migration paths was first observed. It holds profound significance for the design of MOF-Molecule catalysts with efficient charge carrier separation and precise regulation of single-atom coordination sphere.

Surface‐Grafted Single‐Atomic Pt−Nx Complex with a Precisely Regulating Coordination Sphere for Efficient Electron Acceptor‐Inducing Interfacial Electron Transfer

AbstractBased on the electron‐withdrawing effect of the Pt(bpy)Cl2 molecule, a simple post‐modification amide reaction was firstly used to graft it onto the surface of NH2‐MIL‐125, which performed as a highly efficient electron acceptor that induced the conversion of the photoinduced charge migration pathway from internal BDC→TiOx migration to external BDC→PtNx migration, significantly improving the efficiency of photoinduced electron transfer and separation. Furthermore, precisely regulating over the first coordination sphere of Pt single atoms was achieved using further post‐modification with additional bipyridine to investigate the effect of Pt−Nx coordination numbers on reaction activity. The as‐synthesized NML‐PtN2 exhibited superior photocatalytic hydrogen evolution activity of 7.608 mmol g−1 h−1, a remarkable improvement of 225 and 2.26 times compared to pristine NH2‐MIL‐125 and NML‐PtN4, respectively. In addition, the superior apparent quantum yield of 4.01 % (390 nm) and turnover frequency of 190.3 h−1 (0.78 wt % Pt SA; 129 times compared to Pt nanoparticles/NML) revealed the high solar utilization efficiency and hydrogen evolution activity of the material. And macroscopic color changes caused by the transition of carrier migration paths was first observed. It holds profound significance for the design of MOF‐Molecule catalysts with efficient charge carrier separation and precise regulation of single‐atom coordination sphere.