Surface Area Parameters Research Articles

Intra-Aneurysmal High-Resolution 4D MR Flow Imaging for Hemodynamic Imaging Markers in Intracranial Aneurysm Instability.

Prediction of aneurysm instability is crucial to guide treatment decisions and to select appropriate patients with unruptured intracranial aneurysms (IAs) for preventive treatment. High-resolution 4D MR flow imaging and 3D quantification of aneurysm morphology could offer insights and new imaging markers for aneurysm instability. In this cross-sectional study, we aim to identify 4D MR flow imaging markers for aneurysm instability by relating hemodynamics in the aneurysm sac to 3D morphologic proxy parameters for aneurysm instability. In 35 patients with 37 unruptured IAs, a 3T MRA and a 7T 4D MRI flow scan were performed. Five hemodynamic parameters-peak-systolic wall shear stress (WSSMAX) and time-averaged wall shear stress (WSSMEAN), oscillatory shear index (OSI), mean velocity, and velocity pulsatility index-were correlated to 6 3D morphology proxy parameters of aneurysm instability-major axis length, volume, surface area (all 3 size parameters), flatness, shape index, and curvedness-by Pearson correlation with 95% CI. Scatterplots of hemodynamic parameters that correlated with IA size (major axis length) were created. WSSMAX and WSSMEAN correlated negatively with all 3 size parameters (strongest for WSSMEAN with volume (r = -0.70, 95% CI -0.83 to -0.49) and OSI positively (strongest with major axis length [r = 0.87, 95% CI 0.76-0.93]). WSSMAX and WSSMEAN correlated positively with shape index (r = 0.61, 95% CI 0.36-0.78 and r = 0.49, 95% CI 0.20-0.70, respectively) and OSI negatively (r = -0.82, 95% CI -0.9 to -0.68). WSSMEAN and mean velocity correlated negatively with flatness (r = -0.35, 95% CI -0.61 to -0.029 and r = -0.33, 95% CI -0.59 to 0.007, respectively) and OSI positively (r = 0.54, 95% CI 0.26-0.74). Velocity pulsatility index did not show any statistically relevant correlation. Out of the 5 included hemodynamic parameters, WSSMAX, WSSMEAN, and OSI showed the strongest correlation with morphologic 3D proxy parameters of aneurysm instability. Future studies should assess these promising new imaging marker parameters for predicting aneurysm instability in longitudinal cohorts of patients with IA.

Co@NC Chainmail Nanowires for Thermo- and Electrocatalytic Oxidation of 2,5-Bis(hydroxymethyl)furan to 2,5-Furandicarboxylic Acid.

2,5-Furandicarboxylic acid (FDCA) has emerged as an important bio-based furanic compound, which has broad application prospects in renewable energy and materials, especially in the preparation of polyethylene 2,5-furandicarboxylate (PEF). While the conventional synthesis of FDCA involves oxidation of 5-hydroxymethylfurfural (HMF) as a substitute, the thermal and chemical instability of HMF due to its aldehyde group poses challenges. A more favorable alternative is the utilization of 2,5-bis(hydroxymethyl)furan (BHMF), a non-aldehyde and more stable precursor. This study pioneeringly reports nitrogen-doped-carbon encapsulated cobalt (Co@NC) chainmail nanowires for the thermal and electrocatalytic oxidation of BHMF to FDCA. The Co@NC/NF achieved a 97.9 % conversion of BHMF with a 93.3 % yield of FDCA at 1.475 V vs. RHE, whereas thermal catalysis only obtained 14.9 % FDCA yield after 10 hours. Kinetic studies indicated that the large electrochemically active surface area and excellent kinetic parameters contribute its superior electrochemical performance. Mechanistic analysis revealed that the migration of inner electrons to the exterior modified the electronic properties of the carbon layer, thereby facilitating the oxidation of BHMF. Furthermore, the in-situ generation of high-valent cobalt species markedly accelerated the BHMF oxidation. This research underscores the potential of carbon-encapsulated metal chainmail catalysts in thermal and electrochemical biomass conversion.

Metabolic pathways regulated by strigolactones foliar spraying enhance osmoregulation and antioxidant defense in drought-prone soybean

BackgroundDrought stress is a significant abiotic stressor that hinders growth, development, and crop yield in soybeans. Strigolactones (SLs) positively regulate plant resistance to drought stress. However, the impact of foliar application of SLs having different concentrations on soybean growth and metabolic pathways related to osmoregulation remains unknown. Therefore, to clarify the impact of SLs on soybean root growth and cellular osmoregulation under drought stress, we initially identified optimal concentrations and assessed key leaf and root indices. Furthermore, we conducted transcriptomic and metabolic analyses to identify differential metabolites and up-regulated genes.ResultsThe results demonstrated that drought stress had a significant impact on soybean biomass, root length, root surface area, water content and photosynthetic parameters. However, when SLs were applied through foliar application at appropriate concentrations, the accumulation of ABA and soluble protein increased, which enhanced drought tolerance of soybean seedlings by regulating osmotic balance, protecting membrane integrity, photosynthesis and activating ROS scavenging system. This also led to an increase in soybean root length, lateral root number and root surface area. Furthermore, the effects of different concentrations of SLs on soybean leaves and roots were found to be time-sensitive. However, the application of 0.5 µM SLs had the greatest beneficial impact on soybean growth and root morphogenesis under drought stress. A total of 368 differential metabolites were screened in drought and drought plus SLs treatments. The up-regulated genes were mainly involved in nitrogen compound utilization, and the down-regulated metabolic pathways were mainly involved in maintaining cellular osmoregulation and antioxidant defenses.ConclusionsSLs enhance osmoregulation in soybean plants under drought stress by regulating key metabolic pathways including Arachidonic acid metabolism, Glycerophospholipid metabolism, Linoleic acid metabolism, and Flavone and flavonol biosynthesis. This study contributes to the theoretical understanding of improving soybean adaptability and survival in response to drought stress.

Dual admixtures for cement-based composites comprising steel slag powder and residual lignin-based liquor

Steel slag is a by-product of the steel industry that can be used as an aggregate and/or mineral admixture, conferring physical and mechanical benefits to cement-based composites. In parallel, sugarcane bagasse is a by-product of the sugar/alcohol industry used in biorefineries to produce bioethanol. The delignification processes, employed as a pretreatment in biorefineries, generate residual liquors that contain lignin. Lignin is a natural polymer with plasticizing properties when incorporated into cement mixtures. Given this scenario, this work sought to produce and evaluate dual admixtures containing a residual lignin-based liquor and a steel slag powder. The proposed dual admixtures were prepared from two strategies and incorporated in cement pastes and mortars at different dosages. Mixtures containing a commercial silica suspension and a reference mixture (without admixtures) were also evaluated. The flow test showed that the dual admixtures promoted higher spreading than the silica suspension in all the proposed dosages. Also, the mortars containing the dual admixtures had significantly higher compressive strengths and more refined pore structures than the reference mortar. The residual lignin-based liquor enhanced the workability of the composites and favored the dispersion of the steel slag powder into the matrix. The liquor's plasticizing and set-retarding capacities were attributed to its anionic functional groups and sugar content, respectively. Additionally, the high-efficiency grinding of the steel slag powder contributed to improving its specific surface area and fineness parameters, justifying its performance as a filler and a supplementary cementitious material. This study presents a new route for developing more eco-efficient cement-based composites. It also complies with the principles of circular economy by offering a feasible strategy for valorizing large-scale industrial wastes in civil construction.

The Concept of Ideal Lips of Caucasian Female: An Anthropometric Analysis of the Lower Third of the Face.

The demand for lip-redefining procedures has been rising in recent years, thus creating the need for reliable and detailed reference sources on aesthetic female lips. This study investigates the morphology of the lower third of the face, including the lips and jawline, of attractive young Caucasian females. A semi-automatic photogrammetric analysis of the faces of professional female photograph models (n=400) of the Caucasian race aged 18-39 was performed. Angular, linear, and surface area parameters were evaluated. A graphical summarization of the average facial shape of all analyzed attractive females was generated as an average body contours (ABC) image. The height of the lower third of the face equaled 0.32 ± 0.02 of the total facial height. The average lip width was 48.06 ± 3.34mm. The upper vermilion height was found to be significantly lower than the lower vermilion height (6.47 ± 1.36 vs. 11.64 ± 1.46mm, p < 0.01). The lip obliquity angle was found to be 1.05° ± 0.79°. The area surface of the upper lip vermilion was considerably smaller than the vermilion of the lower lip (p < 0.01). This is one of the largest studies on attractive Caucasian females' lips and lower face morphology. The data it provides, including the graphical presentation of the aesthetic lower face as an ABC image, may provide physicians with valuable guidelines for lips rejuvenation and reconstruction procedures. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Sustainable Recycling Approach to Regenerate Graphite from Industrially Sourced Failed Anodes

Recycling graphite from Li-ion battery (LIB) waste plays an important role in increasing the accessibility of graphite resources and sustainable recovery. This presentation describes our work to purify graphite from failed (i.e., out-of-specification) anodes in LIB manufacturing by focusing on the most common contaminant: copper, used as the current collector in LIB anodes.A new, three-step scalable and environmentally friendly approach was used to provide a cost-effective and sustainable method in industrial settings to recycle failed anodes during the early stages of battery manufacturing.The study aimed to understand the differences between new, battery-grade graphite and recycled graphite from anode production waste. In particular, focus was placed on the effect of metallic Cu residues on electrochemical performance. The efficiency of Cu removal from graphite was quantified by Microwave Plasma – Atomic Emission Spectroscopy (MP-AES) analysis of leachates. The following experimental parameters were studied to maximize Cu leaching efficiency: solid-to-liquid ratio, temperature, acid concentration, time and stirring speed.The surface morphology and elemental composition of leached and thermally treated purified graphite were analysed by Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS) and Laser Induced Breakdown Spectroscopy (LIBS). The specific surface area and crystallographic parameters were measured by Braunauer–Emmett–Teller Analysis (BET) and X-Ray Diffraction (XRD), respectively. The electrochemical performance was evaluated by galvanostatic cycling with potential limitation versus Li+/Li. These five techniques were carried out on the solid residues after each stage of the regeneration procedure. The results were compared with battery-grade graphite to assess the effectiveness of our sustainable recycling approach to reuse graphite from failed anodes in LIBs.

The relationship between sphenoidal sinus and sella turcica morphometry in the Turkish population: a retrospective study.

The anatomical position of the sphenoidal sinus (SS) is very important for neurosurgeons because of the transsphenoidal approach to the pituitary gland. Therefore, the aim of this study was to determine the volume and shape of the SS and its relationship with the morphometry of the sella turcica. This study included CT images of 282 males and 258 females with a mean age of 50.52 years (range 18-75) who underwent head CT. The morphometric values of the sella turcica and the volume of the SS were measured on the included radiologic images. Measurements were made on the sagittal slice closest to the midline in T1 sequence. Morphometric measurements were made with Micro Dicom Viewers software program and volume measurements were made with ITK SNAP software program. In this study, 4 types of SS shapes were obtained in the whole population: amorphous, pentagonal, triangular and quadrilateral. The mean SS volume was 7055.88 mm3 in males and 5694.48 mm3 in females and a statistically significant difference was observed (p < 0.001). In addition, a statistically significant difference was found between the sexes in the width and surface area parameters of the sella turcica (p < 0.05). In this study, the morphometric relationship between the shape of the sinus sphenoidale and sella turcica was demonstrated between men and women. In particular, the shape of the sinus sphenoidale was found to be anthropometrically different between men and women in the Turkish population. It is hypothesised that the data obtained in our study will guide surgeons performing transsphenoidal approach.

Laser treated novel textures for adhesion performance of aluminum alloy joints exposed to corrosion

The aim of this study was to investigate novel laser-treated structures designed to improve the adhesion performance and corrosion resistance of AA7075-T6 bonded joints. The spacing, position, and surface area parameters of the laser-treated grooves were investigated to understand their role in adhesion performance even under corrosion conditions. Laser-treated surfaces were analyzed using microscopic, topographic, and chemical methods to determine their scientific contribution to adhesion and corrosion performance. Laser-treated adherends were also bonded to mechanically test their bond strength both before and after exposure to corrosion for varying periods of time. Roughness and therefore surface area have a significant effect on adhesion performance; however, it is worth noting that the best adhesion performance both before and after corrosion exposure was achieved when the required surface area was properly designed and, laser treated according to the salt water exposure directions to inhibit its diffusion into the adhesion interface. The performance of the novel laser-treated structures in terms of adhesion performance under corrosive atmosphere was also supported by failure analysis. The mixed failure mode was significantly shifted to the cohesive failure mode, especially for bonded joints with box-type laser-treated structures.

Quantitative morphological analysis framework of infant cranial sutures and fontanelles based on CT images.

Characterizing the suture morphological variation is a crucial step to investigate the influence of sutures on infant head biomechanics. This study aimed to establish a comprehensive quantitative framework for accurately capturing the cranial suture and fontanelle morphologies in infants. A total of 69 CT scans of 2-4 month-old infant heads were segmented to identify semilandmarks at the borders of cranial sutures and fontanelles. Morphological characteristics, including length, width, sinuosity index (SI), and surface area, were measured. For this, an automatic method was developed to determine the junction points between sutures and fontanelles, and thin-plate-spline (TPS) was utilized for area calculation. Different dimensionality reduction methods were compared, including nonlinear and linear principal component analysis (PCA), as well as deep-learning-based variational autoencoder (VAE). Finally, the significance of various covariates was analyzed, and regression analysis was performed to establish a statistical model relating morphological parameters with global parameters. This study successfully developed a quantitative morphological framework and demonstrate its application in quantifying morphologies of infant sutures and fontanelles, which were shown to significantly relate to global parameters of cranial size, suture SI, and surface area for infants aged 2-4 months. The developed framework proved to be reliable and applicable in extracting infant suture morphology features from CT scans. The demonstrated application highlighted its potential to provide valuable insights into the morphologies of infant cranial sutures and fontanelles, aiding in the diagnosis of suture-related skull fractures. Infant suture, Infant fontanelle, Morphological variation, Morphology analysis framework, Statistical model.

Characterization of Pediatric Rectal Absorption, Drug Disposition, and Sedation Level for Midazolam Gel Using Physiologically Based Pharmacokinetic/Pharmacodynamic Modeling.

This study aims to explore and characterize the role of pediatric sedation via rectal route. A pediatric physiologically based pharmacokinetic-pharmacodynamic (PBPK/PD) model of midazolam gel was built and validated to support dose selection for pediatric clinical trials. Before developing the rectal PBPK model, an intravenous PBPK model was developed to determine drug disposition, specifically by describing the ontogeny model of the metabolic enzyme. Pediatric rectal absorption was developed based on the rectal PBPK model of adults. The improved Weibull function with permeability, surface area, and fluid volume parameters was used to extrapolate pediatric rectal absorption. A logistic regression model was used to characterize the relationship between the free concentrations of midazolam and the probability of sedation. All models successfully described the PK profiles with absolute average fold error (AAFE) < 2, especially our intravenous PBPK model that extended the predicted age to preterm. The simulation results of the PD model showed that when the free concentrations of midazolam ranged from 3.9 to 18.4 ng/mL, the probability of "Sedation" was greater than that of "Not-sedation" states. Combined with the rectal PBPK model, the recommended sedation doses were in the ranges of 0.44-2.08 mg/kg for children aged 2-3 years, 0.35-1.65 mg/kg for children aged 4-7 years, 0.24-1.27 mg/kg for children aged 8-12 years, and 0.20-1.10 mg/kg for adolescents aged 13-18 years. Overall, this model mechanistically quantified drug disposition and effect of midazolam gel in the pediatric population, accurately predicted the observed clinical data, and simulated the drug exposure for sedation that will inform dose selection for following pediatric clinical trials.

Bioactive glass doped with zinc-based metal–organic frameworks (Zn/MOF) nanoparticles for antibiotic delivery applications

Zn-MOF/bioactive glass nanoparticles were successfully prepared using quick–alkali-modified sol–gel and tested for gentamicin drug delivery. Samples of 0 and 0.8 mol% Zn MOF contents (BG and BG/Zn MOF, respectively) were characterized using XRD, FTIR, TEM, and SEM/EDX. In addition, zeta characteristics and surface area parameters were also evaluated. Moreover, the cell viability of the prepared samples was tested against the osteosarcoma MG-63 cell line to evaluate the ability of prepared samples for bone regeneration. In addition, the antimicrobial activity of glass samples with and without antibiotics was determined against different microorganisms. Finally, the samples were loaded with gentamicin drug, and drug release profile and kinetics were studied too. XRD and FTIR results confirmed the physicochemical properties of the prepared samples. TEM results showed that particles were in the nano-sized range in both samples; however, the presence of Zn MOF increased the dispersity of particles. Both samples were bioactive, as indicated by hydroxyapatite formation on their surfaces. Cytotoxicity estimation of prepared materials exhibited their safe and nontoxic nature. BG/Zn MOF sample demonstrated prolonged drug release and excellent antimicrobial activity in comparison to BG alone. Therefore, the present study provides promising preliminary results regarding the usage of BG/Zn MOF nanoparticles loaded with gentamicin as an effective approach for bone regeneration.Graphical

Three-dimensional modelling and morphometric analysis of skull of badger (Meles meles) with computed tomography images.

Morphometric measurements help to understand the skull morphology in different animal species, detect skull deformations and figure out their causes. The aim of this study is to make a three-dimensional (3D) modelling of the badger skull using computed tomography, to show its anatomical structures and to reveal the morphometric measurement values. Skull measurements were carried out using a digital calliper at 27 measurement points based on metric measurement points. After the scanned images were stored in Digital Imaging and Communications in Medicine format, they were transferred to MIMICS 20.1 (The Materialize Group) programme and 3D models the skulls were created. The surface area and volume values of the skulls were calculated on these models. The volume and surface area parameters were expressed as mean±SE. Four different indices were calculated using osteometric measurements. Statistical analyses were made by determining the mean value and standard deviation of the examined properties and the correlation coefficients among these properties. In the metric measurement points taken as a basis, the longest measurement in the skulls was the total length and its mean value was 124.60±0.64mm. The shortest measurement was the breadth dorsal to the external auditory meatus, and its mean value was 6.75±0.24mm. Consequently, statistical differences in the craniometric values of badgers' skulls were determined by using CT and 3D modelling software. In addition, it was concluded that the badger skull can be easily distinguished from other carnivore species by carrying out morphometric measurements.

Influence of Heat Stress on Body Surface Temperature and Blood Metabolic, Endocrine, and Inflammatory Parameters and Their Correlation in Cows.

This study aimed to determine whether heat stress affected the values and correlations of metabolic, endocrinological, and inflammatory parameters as well as the rectal and body surface temperature of cows in the early and middle stages of lactation. This experiment was conducted in May (thermoneutral period), June (mild heat stress), and July (moderate to severe heat stress). In each period we included 15 cows in early lactation and 15 in mid-lactation. The increase in rectal and body surface temperatures (°C) in moderate to severe heat stress compared to the thermoneutral period in different regions was significant (p < 0.01) and the results are presented as mean and [95%CI]: rectal + 0.9 [0.81-1.02], eye + 6 [5.74-6.25], ear + 13 [11.9-14.0], nose + 3.5 [3.22-3.71], forehead + 6.6 [6.43-6.75], whole head + 7.5 [7.36-7.68], abdomen + 8.5 [8.25-8.77], udder + 7.5 [7.38-7.65], front limb + 6 [5.89-6.12], hind limb + 3.6 [3.46-3.72], and whole body + 9 [8.80-9.21]. During heat stress (in both mild and moderate to severe stress compared to a thermoneutral period), an increase in the values of extracellular heat shock protein 70 (eHsp70), tumor necrosis factor α (TNFα), cortisol (CORT), insulin (INS), revised quantitative insulin sensitivity check index (RQUICKI), urea, creatinine, total bilirubin, aspartate transpaminase (AST), gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), and creatin kinase (CK) occurred, as well as a decrease in the values of triiodothyronine (T3), thyroxine (T4), non-esterified fatty acids (NEFA), glucose (GLU), β-Hydroxybutyrate (BHB), calcium, phosphorus, total protein (TPROT), albumin (ALB), triglycerides (TGCs), and cholesterol (CHOL). In cows in early lactation compared to cows in mid-lactation, there was a significantly larger increase (p < 0.01) in the values of eHsp70, TNFα, GLU, RQUICKI, and GGT, while the INS increase was smaller during the three experimental periods. The decrease in the values of Ca, CHOL, and TGC was more pronounced in cows in early lactation compared to cows in mid-lactation during the three experimental periods. Rectal temperature was related to eHsp70 (r = 0.38, p < 0.001) and TNFα (r = 0.36, p < 0.01) and showed non-significant poor correlations with other blood parameters. Blood parameters correlate with body surface temperature, with the following most common results: eHsp70 and TNFα showed a moderately to strongly significant positive correlation (r = 0.79-0.96, p < 0.001); CORT, INS, and Creat showed fairly to moderately significant positive correlations; T3, T4, NEFA and GLU showed fairly to moderately significant negative correlations (r = 0.3-0.79; p < 0.01); RQUICKI, urea, AST, and GGT showed fairly and significantly positive correlations; and TGC, CHOL, TPROT, and ALB showed fairly and significantly negative correlations (r = 0.3-0.59; p < 0.01). Measuring the surface temperature of the whole body or head can be a useful tool in evaluating the metabolic response of cows because it has demonstrated an association with inflammation (TNFα, eHsp70), endocrine response (CORT, T3, T4), the increased use of glucose and decreased use of lipids for energy purposes (INS, NEFA, GLU, and RQUICKI), and protein catabolism (ALB, TPROT, urea, Creat), which underlies thermolysis and thermogenesis in cows under heat stress. In future research, it is necessary to examine the causality between body surface area and metabolic parameters.

Biocrude extraction from human-excreta-derived hydrochar for sustainable energy and agricultural applications

Hydrothermal carbonization may be a sustainable sanitary treatment for wet organic waste including human excreta. Human-excreta-derived hydrochar properties differ from those of typical wet biomass due to the formation of a biocrude-like phase at low reaction temperatures. This study characterized the importance of this phase in terms of hydrochar combustion properties and potential agricultural use. Hydrothermal carbonization of raw human excreta was undertaken at 180, 210, and 240 °C, after which the biocrude phase was extracted with dichloromethane. Physicochemical properties, surface-area parameters, combustion profiles, and gas emissions of non-extracted hydrochar, biocrude, and extracted hydrochar were compared. The potential agricultural use of extracted hydrochar was assessed in germination experiments. Biocrude comprised up to 49.5% of hydrochar mass with a calorific value of >60% that of extracted hydrochar. Biocrude combustion properties were better than those of hydrochar, before and after extraction as demonstrated by higher combustion index value (Si). The extracted hydrochar surface area (34.7 m2 g−1) was greater than that of non-extracted hydrochar (<2 m2 g−1), and seeds germinated more readily due to the lower phytotoxin content. Most macro and micronutrients required for plant growth were retained in the extracted hydrochar. The extraction of biocrude from human-excreta-derived hydrochar not only provided a higher-quality fuel with enhanced combustion properties but also improved hydrochar characteristics, suggesting its potential as a soil additive for enhanced plant growth.

Osteometric and topographic measurement of the skull and mandible of Siirt coloured mohair goat with three-dimensional (3D) modelling technique.

The Siirt coloured mohair goat is one of the breeds that has contributed significantly to the existence of mohair goats reared in Türkiye. Morphological and morphometric characteristics of the Siirt coloured mohair goat remained vague owing to a lack of studies. Recent advances in high-tech imaging have replaced conventional two-dimensional anatomical structures with three-dimensional (3D) models. In our study, morphometric features were determined by 3D modelling from computed tomography images obtained from the skull and mandibular bones of Siirt coloured mohair goats. For this purpose, the skulls and mandibular bones of 20 Siirt coloured mohair goats (10 females and 10 males) were used. The images were reconstructed with the help of the 3D Slicer (5.0.2) software program. The craniometric data were analysed in terms of sexual dimorphism, and statistically significant difference was found in the A5, A18, and A31 measurement parameters (p < 0.05) and skull index (p < 0.01) parameters. In the mandible measurements, there was a statistically significant difference between the sexes in C5, C10 measurement points (p < 0.05), C2, C8, C12, C18, and C21 measurement points (p < 0.001) and surface area parameter (p < 0.01). The morphometric data obtained is a resource in the fields of zoo archaeology, anatomy, forensics, anaesthesia, surgery, and treatment.

Nitrogen and sulphur co-doped carbon-based composites as electrocatalysts for the anion-exchange membrane fuel cell cathode

Nitrogen and sulphur co-doped nanocarbon composites based on silicon carbide-derived carbon (SiCDC), carbon nanotubes (CNT) and/or mesoporous carbon (MPC) are prepared for oxygen reduction reaction (ORR) and anion-exchange membrane fuel cell (AEMFC) studies. Thiosemicarbazide is used as nitrogen and sulphur doping agent. The rotating ring-disc electrode (RRDE) measurements exhibit good electrocatalytic activity towards the ORR for all the prepared catalysts in alkaline solution. Obtained materials are rich in pyridinic-N and consist of thiophene-S, which could improve the ORR performance due to the synergistic effect of N and S. Textural properties, including specific surface area (SSA) and porosity parameters are different amongst the three studied N,S-doped nanocomposite materials, which also affect the outcome of AEMFC test results. In AEMFC testing using Aemion+ (AF2-HLE8-10-X, 10 μm) anion-exchange membrane, N,S-SiCDC/MPC (with SSAdft = 952 m2 g−1) shows the highest performance with the peak power density (Pmax) of 379 mW cm–2. This result is comparable with the performance of Pt/C catalyst in AEMFC (Pmax = 347 mW cm–2), making N,S-doped nanocomposite materials promising cathode catalyst for AEMFCs.

Adsorption Of Methylene Blue Using Active Charcoal From Empty Fruit Bunch (EFB)

Research on the adsorption of methylene blue by activated charcoal from Empty Fruit Bunch (EFB) has been carried out. This study aimed to synthesize activated charcoal from EFB, characterize it, and use it as an adsorbent for methylene blue. Activated charcoal was synthesized by carbonation in a furnace at 300oC for 1 hour. Chemically, activation was carried out by immersion in HCl solution for 24 hours. Characterization was carried out by proximate test, determination of functional groups using Fourier Transform Infrared (FT-IR), and determining material shape with X-Ray Diffraction (XRD). The study of activated charcoal adsorption as methylene blue adsorbent was carried out by treating variations in contact time, adsorbent weight, and concentration. The results of the proximate test with the parameters of surface area, moisture content, and ash content were 162.12 m2/g, 0.52%, and 5.27%, respectively. The results of the FT-IR characterization test showed an aromatic C–H, C=C and C–O. Based on the results of characterization with XRD giving a pattern at a diffraction angle of 2 20 - 30o, it was seen that there was a wide peak, which indicated that it had an amorphous structure. The optimum conditions for methylene blue adsorption occurred at a contact time of 40 minutes, and the adsorbent weight was 0.1 g for 10 mL of 50 ppm methylene blue. The adsorption of methylene blue followed the Freundlich isotherm adsorption pattern and had a maximum adsorption capacity of 8.92 mg/g.

Mechanics of ascending aortic aneurysms based on a modulus of elasticity dependent on aneurysm diameter and pressure

The mechanical stresses and strains are examined, in ascending thoracic aortic aneurysm (aTAA) models, in a patient-specific aTAA as well as in healthy thoracic aortic models, via Finite Element Analysis. The aneurysms are assumed spherical, 1.5 mm thick, with diameters between 47 mm and 80 mm, eccentrically positioned. The geometry and wall thickness distribution of the aorta along its length are based on open literature data for an average patient age of 66.25 years, accounting for the Body Surface Area (BSA) parameter. The vessel wall material is assumed isotropic and incompressible, with its Young’s modulus varying with the aneurysm diameter and the applied intraluminal pressure (120 mmHg to 240 mmHg). In the aTAAs, peak stresses were found to increase nonlinearly with aneurysm diameter (for a given pressure) tending to reach a plateau, appearing at the proximal area of the aneurysm, whereas lower stresses were found at its distal part and even smaller at the aneurysm maximum diameter. Regarding the patient-specific aTAA model, the peak stresses appeared at the distal part of the aneurysm where a tear of the intima layer was detected during surgical intervention. Peak strains exhibited for each pressure a maximum at a certain aneurysm diameter beyond which they dropped so that essentially the vessel wall’s distensibility was thus reduced. Examining more than 100 geometry cases and employing a failure stress criterion, the rupture diameter thresholds were estimated to be 65, 52.5, 50 and 47.5 mm for a pressure of 120, 160, 200 and 240 mmHg respectively.

Assessment of longitudinal brain development using super-resolution magnetic resonance imaging following fetal surgery for open spina bifida.

Prenatal surgery is offered for selected fetuses with open spina bifida (OSB) to improve long-term outcome. We studied the effect of fetal OSB surgery on brain development using advanced magnetic resonance imaging (MRI) techniques to quantify the volume, surface area and shape of cerebral structures and to analyze surface curvature by means of parameters that correspond to gyrification. We compared MRI data from 29 fetuses with OSB before fetal surgery (mean gestational age (GA), 23 + 3 weeks) and at 1 and 6 weeks after surgery, with that of 36 GA-matched control fetuses (GA range, 21 + 2 to 36 + 2 weeks). Automated super-resolution reconstruction provided three-dimensional isotropic volumetric brain images. Unmyelinated white matter, cerebellum and ventricles were segmented automatically and refined manually, after which volume, surface area and shape parameter (volume/surface area) were quantified. Mathematical markers (shape index (SI) and curvedness) were used to measure gyrification. Parameters were assessed according to lesion type (myelomeningocele vs myeloschisis (MS)), postoperative persistence of hindbrain herniation (HH) and the presence of supratentorial anomalies, namely partial agenesis of the corpus callosum (pACC) and heterotopia (HT). Growth in ventricular volume per week and change in shape parameter per week were higher at 6 weeks after surgery in fetuses with OSB compared with controls (median, 2500.94 (interquartile range (IQR), 1689.70-3580.80) mm3 /week vs 708.21 (IQR, 474.50-925.00) mm3 /week; P < 0.001 and 0.075 (IQR, 0.047-0.112) mm/week vs 0.022 (IQR, 0.009-0.042) mm/week; P = 0.046, respectively). Ventricular volume growth increased 6 weeks after surgery in cases with pACC (P < 0.001) and those with persistent HH (P = 0.002). During that time period, the change in unmyelinated white-matter shape parameter per week was decreased in OSB fetuses compared with controls (0.056 (IQR, 0.044-0.092) mm/week vs 0.159 (IQR, 0.100-0.247) mm/week; P = 0.002), particularly in cases with persistent HH (P = 0.011), MS (P = 0.015), HT (P = 0.022), HT with corpus callosum anomaly (P = 0.017) and persistent HH with corpus callosum anomaly (P = 0.007). At 6 weeks postoperatively, despite OSB fetuses having a lower rate of change in curvedness compared with controls (0.061 (IQR, 0.040-0.093) mm-1 /week vs 0.094 (IQR, 0.070-0.146) mm-1 /week; P < 0.001), reversing the trend seen at 1 week after surgery (0.144 (IQR, 0.099-0.236) mm-1 /week vs 0.072 (IQR, 0.059-0.081) mm-1 /week; P < 0.001), gyrification, as determined using SI, appeared to be increased in OSB fetuses overall compared with controls. This observation was more prominent in fetuses with pACC and those with severe ventriculomegaly (P-value range, < 0.001 to 0.006). Following fetal OSB repair, volume, shape and curvedness of ventricles and unmyelinated white matter differed significantly compared with those of normal fetuses. Morphological brain changes after fetal surgery were not limited to effects on the circulation of cerebrospinal fluid. These observations may have implications for postnatal neurocognitive outcome. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Anthropometric features and functional state of the cardiovascular system in qualified athletes of various sports

Aim. To assess the anthropometric characteristics and functional state of the cardiovascular system in qualified athletes of various sports.Material and methods. A total of 136 male athletes were examined. Qualified athletes (n=116) (age, 22,07±4,10 years, sports experience 9,56±3,08 years) were divided into groups: I (n=30) — wrestling, judo, II (n=27) — cross-country skiing, biathlon, III (n=33) — powerlifting, IV (n=26) — volleyball. Control group (n=20) consisted of those training less than 3 years. We performed anthropometry with assessment of body height and weight, chest circumference, body surface area, body mass index (BMI), Pignet index, Erisman index, grip and back strength test. Echocardiography, cycle ergometry with assessment of physical working capacity (PWC170) and maximum oxygen consumption (MOC). The relationship between traits was assessed using the Spearman rank correlation coefficient (rs). Critical significance level was p=0,05.Results. According to echocardiography, qualified athletes had significant differences in structural parameters. Group II was characterized by an increase in left ventricular (LV) volumetric dimensions and identified correlations of BMI and body surface area with end-diastolic dimension (r=0,602), end-diastolic volume (r=0,591), end-systolic volume (ESV) (r=0,429), stroke volume (r=0,597), PWC170 (r=0,550). Groups I and III were characterized by an increase in LV posterior wall (LVPWT) and interventricular septal (IVST) thickness. In group I, there was a relationship between body surface area and LVPWT (r=0,413); Pignet index with MOC (r=0,623); PWC170 with Erisman index (r=0,573), strength of the right (r=0,610) and left hand (r=0,515), back muscles (r=0,445). Group III had the highest BMI and body surface area, while relationships were identified with LVPWT (r=0,426), IVST (r=0,409), LV mass (LVM) (r=0,453), and back muscle strength (r=0,464); the Erisman index correlated with LVM index (r=0,359). In group IV, the parameters of height, body weight and body surface area are interrelated with LVM (r=0,731), LVPWT (r=0,523), IVST (r=0,399), ESV (r=0,504), end-systolic dimension (r=0,467), right hand strength (r=0,583).Conclusion. The relationships established by correlation analysis showed that anthropometric features are important components and criteria for assessing cardiac hemodynamics function in qualified athletes, depending on the type of sport and the duration of training, which must be taken into account when achieving sports results.