Contents Of Volume Research Articles

Effect of electroacupuncture of "Zusanli" (ST36) combined with capeOX on apoptosis and ferroptosis in nude mice with colorectal cancer.

To investigate the impact of combined treatment of colorectal cancer (CRC) with electroacupuncture (EA) and capeOX (combined administration of fluorouracil, oxaliplatin and capecitabine) on the tumor volume, weight, spleen coefficient, apoptosis and ferroptosis of tumor tissue, and liver and kidney functions in nude mice with CRC, so as to explore its mechanisms underlying inhibiting CRC and alleviating toxic reactions of capeOX. Female Balb/c nude mice were randomly assigned to 3 groups：model, capeOX, and EA+capeOX, with 8 nude mice in each group. The CRC model was established by subcutaneous injection of colon cancer cells at the right inguinal region. Nude mice of the capeOX group received intraperitoneal injection of oxaliplatin for 1 day and gavage of capecitabine from day 2 to day 7. EA (1 mA, 2 Hz/100 Hz) was applied to bilateral "Zusanli" (ST36) for 20 min, once daily for 7 days. During the interven-tion, the tumor volume and weight were measured every day, and at the end of intervention, the weight of the tumor tissue and spleen were measured, with tumor volume difference and spleen coefficient calculated. The proportion of apoptotic cells was measured by flow cytometry, and the contents of serum malondialdehyde (MDA), alanine aninotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) were detected using ELISA. The expression level of glutathione peroxidase 4 (GPX4, a key regulator for ferroptosis) protein of the tumor tissue was determined using Western blot. Compared to the model group, both the capeOX group and EA+capeOX group showed a decrease in the tumor volume (on day 3 and 4 in the capeOX group, and from day 2 to 7 in the EA+capeOX group) and body weight (P<0.05, on day 3 to 7 in the EA+capeOX group and on day 2 to 7 in the capeOX group), being evidently lower in the tumor volume on day 7 in the EA+capeOX than in the capeOX group (P<0.05), and evidently higher in the body weight on day 6 and 7 in the EA+capeOX group than in the capeOX group (P<0.05). In comparison with the model group, the tumor volume difference, tumor weight and spleen coefficient in both capeOX and EA+capeOX groups were significantly decreased (P<0.05), and MDA content in EA+capeOX group was significantly decreased (P<0.05), while the contents of ALT, BUN and Cr in the capeOX group, the proportion of apoptotic cells in both capeOX and EA+capeOX groups, and the GPX4 expression level in the EA+capeOX group were all significantly increased (P<0.05). The tumor volume difference, tumor weight, and contents of MDA, ALT, AST, BUN and Cr in the EA+capeOX group were markedly lower than in the capeOX group (P<0.05), while the spleen coefficient, proportion of apoptotic cells and GPX4 expression level in the EA+capeOX group were markedly higher than those in the capeOX group (P<0.05). EA of ST36 can enhance the effect of capeOX in inhibiting colorectal cancer growth in nude mice with CRC, which may be related with its functions in promoting tumor cell apoptosis, inhibiting ferroptosis, and modulating immune tolerance. In addition, EA can lower the side effects of capeOX in hematopoietic and immune, liver, and kidney functions.

Intestinal microbial and metabolite profile in infants with small bowel stomas after bowel resection.

Infants with small bowel stomas (SBstoma) frequently struggle with absorption and rely on parenteral nutrition (PN). Intestinal absorption is difficult to predict based solely on intestinal anatomy. The purpose of this study was to characterize the microbiota and metabolic by-products within stoma effluent and correlate with clinical features and intestinal absorption. Prospective cohort study collecting stoma samples from neonates with SBstoma (N = 23) or colostomy control (N = 6) at initial enteral feed (first sample) and before stoma closure (last sample). Gut bacteriome (16S rRNA sequencing), short-chain fatty acids (SCFAs) and bile acids (BAs) were characterized along with volume and energy content of a 48 h collection via bomb calorimetry (last sample). Hierarchical clustering and linear regression were used to compare the bacteriome and BAs/SCFAs, to bowel length, PN, and growth. Infants with ≤50% small bowel lost more fluid on average than those with >50% and controls (22, 18, 16 mL/kg/d, p = 0.013), but had similar energy losses (7, 10, 9 kcal/kg/d, p = 0.147). Infants growing poorly had enrichment of Proteobacteria compared to infants growing well (90% vs. 15%, p = 0.004). An increase in the ratio of secondary BAs within the small bowel over time, correlated with poor prognostic factors (≤50% small bowel, >50% of calories from PN, and poor growth). Infants with SBstoma and poor growth have a unique bacteriome community and those with poor enteral tolerance have metabolic differences compared to infants with improved absorption.

Experimental study on mechanical properties and dynamic compression performance of basalt/polypropylene fiber high strength concrete

Concrete is a typical brittle material. Although it has excellent compressive performance, its shortcomings such as poor tensile strength and easy cracking cannot resist the damage of dynamic loads such as explosion and impact to a certain extent. In order to improve the impact resistance of concrete, the φ100 × 50 SHPB was used to carry out the impact tests of high-strength concrete specimens with volume contents of 0.1%, 0.3%,0.5% basalt fiber (BF) and polypropylene fiber (PPF) under three different impact pressures. The compressive strength, splitting tensile strength, flexural strength and dynamic compression performance of basalt/polypropylene fiber high strength concrete (C60) were studied. With the increase of impact pressure, increasing the volume content of fiber can significantly improve the impact resistance of high-strength concrete, which can give full play to the crack resistance and bridging effect of fiber. BF and PPF are sensitive to strain rate. Within a certain range of strain rate, the relationship between peak stress and strain rate is positively correlated. Finally, the dynamic stress-strain curves of the optimal content of two kinds of fibers are obtained through dynamic compression test.

Dielectric percolation in ceramic matrix composites

This paper presents the results of an experimental study of the percolation behavior of the complex dielectric constant of ceramic matrix composites (CMC). Samples of piezoactive CMC were obtained by joint sintering of synthesized PZT piezoceramic powder (matrix) and crushed particles of sintered PZT piezoceramics (filler) of different compositions. The experimental dependencies of real and imaginary parts of the complex dielectric constant of CMC on the porosity of piezoceramic matrix and volume content of ceramic filler particles were measured and analyzed. It was shown that the additional porosity of the ceramic matrix resulting from sintering of the CMC masks the dielectric percolation transition, that actually occurs at the volume concentration of ceramic filler close to percolation threshold (V ∼ 1/3).

Bond Behavior and Failure Mechanisms of the Interface between Engineered Cementitious Composites and Shaped Steel

Due to their excellent ductility and crack-control ability, engineered cementitious composites (ECCs) combined with shaped steel can produce steel-reinforced engineering cementitious composite (SRECC) structures which exhibit significant advantages in prefabricated buildings. The interface bond behavior is the base for the cooperative working performance of the shaped steel and ECC. This study included push-out tests of one ordinary concrete control specimen and ten ECC specimens. The various parameters were the ECC compressive strength, fiber volume content, cover thickness, and the embedded length of shaped steel. The bond stress–slip curves at the loading and free end were obtained, and the effects of various parameters on the characteristic points of curves were analyzed. The results indicated that the ordinary concrete specimen failed in brittle splitting, with the cracks completely penetrating the surface of the specimen. Due to the fiber-bridging effect in ECCs effectively preventing the development and extension of cracks, the shaped steel at the free end was obviously pushed out, and the surrounding matrix maintained good integrity after testing finished. For ECC specimens, bond or splitting-bond failure occurred, exhibiting outstanding ductility. Compared with the ordinary concrete specimen, the standard ultimate and residual bond strength of ECC specimens improved by 37.9% and 27.4%, respectively. Besides the increase in ECC compressive strength, the fiber volume content and cover thickness had a significant positive influence on the ultimate and residual bond strength, whereas the effect of the embedded length was the opposite. Finally, the calculation equations of characteristic bond strength were proposed, and the calculated values matched well with the experimental values.

Bond behavior between highly ductile fiber-reinforced concrete (HDC) and deformed rebar under repeated and post-repeated monotonic loading

This paper tested nine groups of six specimens each to investigate the bond behavior between deformed steel reinforcing bars and highly ductile fiber-reinforced concrete (HDC) under repeated and post-repeated monotonic loading considering different compressive strengths, flexural toughnesses, fiber volume contents and cover thicknesses. The results indicate that fiber bridging of cracks allowed the bonds in the HDC specimens to exhibit more ductile failure mode and greater energy dissipation capacity than those in conventional concrete. Furthermore, an increase in compressive strength or cover thickness improved the bond strength, whereas excessive flexural toughness was detrimental to further improvement in the bond strength and energy dissipation capacity. Finally, the residual bond strength increased by 95.03 % as the fiber volume content increased from 1 % to 2 %. Specimens with insufficient flexural toughness and cover thickness exhibited the deterioration in their bond strength and residual bond strength, with the former degrading more than the latter. After repeated loading, the stiffness of the primary ascending branch of the monotonic bond stress–slip curve significantly increased, whereas that of descending branch generally decreased. These results were applied to derive an equation for the bond strength between deformed bars and the HDC in which they are embedded under post-repeated monotonic loading.

A facile and scalable fabrication method of scrolled graphene/boron nitride-based van der Waals superlattice heterostructure materials for highly stable supercapacitor electrode application.

Due to the increasing demand for the development of efficient renewable energy supply systems to reduce the mismatch between energy demand and utilization, supercapacitors have attracted increasing attention in the energy industry. However, the development of energy storage electrode materials to be applied at the industrial level is still challenging due to the unsatisfactory durability and scalable production issues. This study suggested a facile and scalable one-pot fabrication method of using graphene/hexagonal boron nitride (G/BN)-based one-dimensional (1D) van der Waals superlattice heterostructures (vdWSLs) as highly stable electrode materials to enhance the energy storage performance by improving the mesopore volume content, specific surface area, electrical properties, and interfacial interaction between the stacked G/BN layers. The G/BN-based vdWSLs were fabricated by a simple scrolling process through the electromagnetic interaction between the attached magnetic iron oxide nanoparticles (Fe3O4 NPs) on the surface of a G/BN vdW heterostructure (vdWH) and the applied magnetic field. The investigation results demonstrate that the changed morphology of the fabricated G/Fe/BN(NS) strongly affects the fine pore distribution, electrochemical performance, and electrical properties. Consequently, as a synergistic effect of an increased mesopore volume content, specific surface area, and C-B-N heterojunction interfacial area, the fabricated G/Fe/BN(NS) electrode showed a 100% enhancement of specific capacitance (207 F g-1 at 0.5 A g-1) and almost 7 times enhancement of electrical conductivity (800 S cm-1) with a nearly 2.3 times increase of carrier mobility (716 cm2 V-1 s-1) compared to that of the G/Fe/BN electrode. Furthermore, it exhibited outstanding long-term cycling stability with almost 119% capacitance retention even after 100 000 charge-discharge cycles. These results suggest that G/Fe/BN(NS) has tremendous potential as an electrode to fabricate high-performance supercapacitors with excellent cycling stability.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet is associated with lower visceral and hepatic lipid content in recent-onset type 1 diabetes and type 2 diabetes.

To investigate the associations of the Dietary Approaches to Stop Hypertension (DASH) score with subcutaneous (SAT) and visceral (VAT) adipose tissue volume and hepatic lipid content (HLC) in people with diabetes and to examine whether changes in the DASH diet were associated with changes in these outcomes. In total, 335 participants with recent-onset type 1 diabetes (T1D) and type 2 diabetes (T2D) from the German Diabetes Study were included in the cross-sectional analysis, and 111 participants in the analysis of changes during the 5-year follow-up. Associations between the DASH score and VAT, SAT and HLC and their changes were investigated using multivariable linear regression models by diabetes type. The proportion mediated by changes in potential mediators was determined using mediation analysis. A higher baseline DASH score was associated with lower HLC, especially in people with T2D (per 5 points: -1.5% [-2.7%; -0.3%]). Over 5 years, a 5-point increase in the DASH score was associated with decreased VAT in people with T2D (-514 [-800; -228] cm3). Similar, but imprecise, associations were observed for VAT changes in people with T1D (-403 [-861; 55] cm3) and for HLC in people with T2D (-1.3% [-2.8%; 0.3%]). Body mass index and waist circumference changes explained 8%-48% of the associations between DASH and VAT changes in both groups. In people with T2D, adipose tissue insulin resistance index (Adipo-IR) changes explained 47% of the association between DASH and HLC changes. A shift to a DASH-like diet was associated with favourable VAT and HLC changes, which were partly explained by changes in anthropometric measures and Adipo-IR.

Enhancing the PEEK composites-titanium interface performances through electrochemical treatment in fibre-metal laminates for aerospace applications

In this work, different surface treatments were investigated to improve the adhesion between grade 5 titanium alloy and carbon fibre-reinforced PEEK composites for aerospace applications. Three types of processes were compared: mechanical treatment (MT), carried out by sander with #80 grit sandpaper, chemical treatment, using a silane coupling agent (SIL) and electrochemical treatment, performed by anodic oxidation. The latter was performed by using an ethylene glycol solution composed of 0.5%wt of ammonium fluoride (NH4F) and variable volume content of deionized water: 5%v/v, 20 % v/v, 50 % v/v. The ammonium fluoride content was fixed, while the ethylene glycol percentage depend on the variation of water volume. Two values of electric potential were evaluated: 30V and 50V. Finally, for each potential and water content, three different anodizing times were studied: 10 min, 30 min, and 60 min. Morphology studies were performed through Scanning electron microscopy to evaluate how the anodizing parameters could affect the shape of the nanotubes (NTs) layers. Moreover, short beam shear tests were carried out to evaluate the achieved improvement given by the different surface treatments.

Novel Class of Crystal/Glass Ultrafine Nanolaminates with Large and Tunable Mechanical Properties.

The control of local heterogeneities in metallic glasses (MGs) represents an emerging field to improve their plasticity, preventing the propagation of catastrophic shear bands (SBs) responsible for the macroscopically brittle failure. To date, a nanoengineered approach aimed at finely tuning local heterogeneities controlling SB nucleation and propagation is still missing, hindering the potential to develop MGs with large and tunable strength/ductility balance and controlled deformation behavior. In this work, we exploited the potential of pulsed laser deposition (PLD) to synthesize a novel class of crystal/glass ultrafine nanolaminates (U-NLs) in which a ∼4 nm thick crystalline Al separates 6 and 9 nm thick Zr50Cu50 glass nanolayers, while reporting a high density of sharp interfaces and large chemical intermixing. In addition, we tune the morphology by synthesizing compact and nanogranular U-NLs, exploiting, respectively, atom-by-atom or cluster-assembled growth regimes. For compact U-NLs, we report high mass density (∼8.35 g/cm3) and enhanced and tunable mechanical behavior, reaching maximum values of hardness and yield strength of up to 9.3 and 3.6 GPa, respectively. In addition, we show up to 3.6% homogeneous elastoplastic deformation in compression as a result of SB blocking by the Al-rich sublayers. On the other hand, nanogranular U-NLs exhibit slightly lower yield strength (3.4 GPa) in combination with enhanced elastoplastic deformation (∼6%) followed by the formation of superficial SBs, which are not percolative even at deformations exceeding 15%, as a result of the larger free volume content within the cluster-assembled structure and the presence of crystal/glass nanointerfaces, enabling to accommodate SB events. Overall, we show how PLD enables the synthesis of crystal/glass U-NLs with ultimate control of local heterogeneities down to the atomic scale, providing new nanoengineered strategies capable of deep control of the deformation behavior, surpassing traditional trade-off between strength and ductility. Our approach can be extended to other combinations of metallic materials with clear interest for industrial applications such as structural coatings and microelectronics (MEMS and NEMS).

Mechanical properties of steel fiber-reinforced geopolymer concrete after high temperature exposure

Adding a certain amount of steel fibers can overcome the brittleness defects in geopolymer concrete and improve the mechanical properties, which has a broader application prospect. However, the research on the material properties of steel fiber-reinforced geopolymer concrete (SFGPC) after high temperature exposure is still very limited. Therefore, tests on 114 cubes and 57 prisms after exposure to high temperatures were conducted in this paper. The main variables were temperature (20 °C, 200 °C, 400 °C, 600 °C, and 800 °C), steel fiber volume content (0, 1 %, and 2 %), and concrete type (SFGPC and steel fiber-reinforced ordinary Portland cement concrete (SFOPC)). The results indicated that SFGPC with a steel fiber content of 1 % at 800 °C experienced a 53.6 % reduction in compressive strength, a 58 % reduction in splitting tensile strength, a 93.9 % reduction in elastic modulus, a 45.9 % reduction in toughness index, and a 274.5 % increase in peak strain, compared with room temperature. The 1 % fiber content enhanced the compressive strength by 10.3 %−36.5 %, the splitting tensile strength by more than 16 %, the peak strain by 9.6 %−32.7 %, and the toughness index by 24.4 %−64.6 % compared to the absence of fiber content. Based on the room temperature model, a constitutive model of SFGPC under uniaxial compression after high temperatures was developed.

Mechanical properties of steel fiber-reinforced geopolymer concrete after high temperature exposure

Adding a certain amount of steel fibers can overcome the brittleness defects in geopolymer concrete and improve the mechanical properties, which has a broader application prospect. However, the research on the material properties of steel fiber-reinforced geopolymer concrete (SFGPC) after high temperature exposure is still very limited. Therefore, tests on 114 cubes and 57 prisms after exposure to high temperatures were conducted in this paper. The main variables were temperature (20 °C, 200 °C, 400 °C, 600 °C, and 800 °C), steel fiber volume content (0, 1 %, and 2 %), and concrete type (SFGPC and steel fiber-reinforced ordinary Portland cement concrete (SFOPC)). The results indicated that SFGPC with a steel fiber content of 1 % at 800 °C experienced a 53.6 % reduction in compressive strength, a 58 % reduction in splitting tensile strength, a 93.9 % reduction in elastic modulus, a 45.9 % reduction in toughness index, and a 274.5 % increase in peak strain, compared with room temperature. The 1 % fiber content enhanced the compressive strength by 10.3 %−36.5 %, the splitting tensile strength by more than 16 %, the peak strain by 9.6 %−32.7 %, and the toughness index by 24.4 %−64.6 % compared to the absence of fiber content. Based on the room temperature model, a constitutive model of SFGPC under uniaxial compression after high temperatures was developed.

Preparation and characterization of high load‐bearing needled composite preform based on novel ordered short fiber network needling method

AbstractNeedled preform and its composite using felt and base cloth stacked needled have small fiber volume fraction and relatively weak mechanical properties, which are difficult to meet the service requirements of structural and functional integrated components of high‐speed aircraft. Responding to this issue, this paper proposed a new method for preparing high load‐bearing needled composite preform based on ordered short fiber network needling. The high load‐bearing needled preforms were prepared by designing different structural parameters of ordered short fiber network and forming process parameters, and then preform structure was characterized and mechanical properties were tested. The results showed that using ordered short fiber network as carrier of the short fibers, the formed needled fiber bundles were longer and denser, volume content of needled fiber bundles and mechanical properties of needled preform were greatly improved, and needled fiber bundles volume content of ordered short fiber network reinforced needled preform was 1.5 times and 46.3 times that of half‐cut cloth and felt respectively. Compared with traditional felt needled preform and half‐cut cloth needled preform, the interlaminar peeling strength of the ordered short fiber network reinforced needled preform increased by up to 246.4% and 49.2%, respectively. The tensile strength of ordered short fiber network reinforced needled preform was 12.9% higher than that of half‐cut cloth in X‐axis direction. In addition, the effects of ordered short fiber network structure, short fiber length, areal density and needling density on the needled preform structure and properties were also revealed.Highlights High load‐bearing needled composite preform was prepared based on novel ordered short fiber network needling method. The needled fiber bundles formed by using ordered short fiber network were longer and denser, and their volume content was 46.3 times that of felt needled preform. The interlaminar peeling strength of the ordered short fiber network reinforced needled preform increased by up to 246.4%. The tensile strength of ordered short fiber network reinforced needled preform was 12.9% greater than half‐cut cloth in the X‐axis direction.

Interpretable Machine Learning Models for Prediction of UHPC Creep Behavior

The creep behavior of Ultra-High-Performance Concrete (UHPC) was investigated by machine learning (ML) and SHapley Additive exPlanations (SHAP). Important features were selected by feature importance analysis, including water-to-binder ratio, aggregate-to-cement ratio, compressive strength at loading age, elastic modulus at loading age, loading duration, steel fiber volume content, and curing temperature. Four typical ML models—Random Forest (RF), Artificial Neural Network (ANN), Extreme Gradient Boosting Machine (XGBoost), and Light Gradient Boosting Machine (LGBM)—were studied to predict the creep behavior of UHPC. Via Bayesian optimization and 5-fold cross-validation, the ML models were tuned to achieve high accuracy (R2 = 0.9847, 0.9627, 0.9898, and 0.9933 for RF, ANN, XGBoost, and LGBM, respectively). The contribution of different features to the creep behavior was ranked. Additionally, SHAP was utilized to interpret the predictions by the ML models, and four parameters stood out as the most influential for the creep coefficient: loading duration, curing temperature, compressive strength at loading age, and water-to-binder ratio. The SHAP results were consistent with theoretical understanding. Finally, the UHPC creep curves for three different cases were plotted based on the ML model developed, and the prediction by the ML model was more accurate than that by fib Model Code 2010.

Mechanical strength of an hot-mix asphalt using recycled concrete aggregate: mass and volume proportioning

The generation of solid waste produced by the construction sector is considered a major problem worldwide. Several studies have been conducted to evaluate the use of construction and demolition wastes (CDW) in pavements. Within CDW, one material with great potential for use is recycled concrete aggregate (RCA). The present study evaluated the mechanical performance of a hot-mix asphalt (HMA) that used RCA as a partial substitute for the coarse fraction of the natural aggregate – Nag (particle size retained on 1/2” and 1/2"+3/8” sieves). The substitution was performed in a conventional way by mass and also by volume. To evaluate the performance under monotonic loading, the stability/flow ratio (S/F) of the Marshall test and the Indirect Tensile Strength (ITS) were measured on dry (ITSd) and conditioned (immersed in water, ITSw) samples. The tensile strength ratio (TSR) was calculated to evaluate the resistance to moisture damage. Under cyclic loading, tests of resilient modulus – RM (three temperatures and three loading frequencies), permanent deformation, and fatigue resistance under controlled-stress were performed. Cantabro tests were performed to measure the resistance to abrasive wear. Conventional characterization tests and imaging processing in a scanning electron microscope (SEM) were carried out on particles of RCA and Nag. A Life Cycle Cost Analysis (LCCA) was performed with the results obtained. The general conclusions were as follows: (i) RCA increases the asphalt content in the mixes, however, volume substitution could help to decrease it; (ii) the mixes with RCA met the volumetric and strength parameters established by the Colombian specification (especially for roads with low traffic volumes); (iii) mixes with RCA undergo better mechanical performance in all tests performed, however, resistance to moisture damage may be compromised when dosing by volume and asphalt content decreases; (iv) substitution by mass or volume did not generate clear trends in the results, but better overall performance is reported in mixes dosed by volume. It is recommended to carry out more studies where Nag is replaced by RCA in volume.

Experimental Study on Impact Performance of Basalt-Polypropylene Fiber Reinforced High-Performance Concrete.

To enhance the impact resistance of high-performance concrete (HPC), a novel efficient solution was adopted by incorporating basalt fibers (BF) and polypropylene fibers (PF) as reinforcement materials in this work. To this end, the effects of single BF (BHC) and PF (PHC) as well as their combinations (BPHPC) on the impact energy consumption, ductility ratio, and toughness factor were explored through drop weight impact test of concrete considering fiber volume contents (0.1%, 0.15%, 0.2%) to evaluate the impact resistance of the concrete. The Weibull distribution function model is used to fit the drop weight impact test results and predict the probability of failure. Moreover, the fracture-resistance enhancement mechanism of fiber is analyzed at a microscopic level. Test results showed that the number of impacts resisted by the HPC can follow well the two-parameter Weibull distribution. Compared with the single BF and single PF, the combination of 0.15% BF and 0.1% PF yields favorable impact resistance, thus exhibiting a positive hybrid effect.

Self-organization of C60 fullerene molecules in xylene/ethanol mixtures

Fullerene molecules have been intensively studied over the past few decades due to their unique chemical and physical properties, which have great potential in a wide range of applications. In this article, the formation and aging of C60 colloids in the xylene/ethanol system is considered. The peculiarities of these processes are studied by the methods of refractometry, optical absorption, Raman spectroscopy and dynamic light scattering (DLS). It has been experimentally established that the formation of colloidal particles in a C60/xylene/ethanol mixture depends on the volume content of the components and the storage time of the solution. The time required to achieve stability of self-organization of solute molecules in a C60/xylene/ethanol mixture is discussed.

Self-organization of C60 fullerene molecules in xylene/ethanol mixtures

Fullerene molecules have been intensively studied over the past few decades due to their unique chemical and physical properties, which have great potential in a wide range of applications. In this article, the formation and aging of C60 colloids in the xylene/ethanol system is considered. The peculiarities of these processes are studied by the methods of refractometry, optical absorption, Raman spectroscopy and dynamic light scattering (DLS). It has been experimentally established that the formation of colloidal particles in a C60/xylene/ethanol mixture depends on the volume content of the components and the storage time of the solution. The time required to achieve stability of self-organization of solute molecules in a C60/xylene/ethanol mixture is discussed.

Evaluation of Select Monarda Taxa in Montane and Piedmont Regions of Georgia: II. Floral Morphology and Nectar Production

We analyzed the floral morphology and nectar production of several cultivars and species of Monarda representing five cultivars and four species grown in Georgia Piedmont and Montane regions. Over the course of two seasons, we detected significant differences among the samples in terms of inflorescence size, petal lobe and corolla widths and lengths, and total sugar content. M. didyma had larger glomerules, longer corollas and petal lobes, and higher nectar volume and total sugar content per flower. M. fistulosa and M. punctata had smaller glomerules, corolla and petal lobe lengths, and total sugar content per flower. Petal lobe and corolla length strongly correlated with sucrose and nectar production. Combined with data on horticultural performance, these results could be valuable in informing breeding goals for conservation-oriented landscape plants.

A piece-wise linear model for modelling the tension-stiffening effect in steel-reinforced UHPC composites

This study examines the tensile behaviour of Ultra-High Performance Concrete (UHPC) specimens reinforced with varying steel fibre content and rebar diameters. An experimental campaign involving 18 reinforced UHPC specimens was conducted, following individual tensile response characterizations of UHPC and reinforcing steel. These specimens were designed and fabricated with threaded welded steel cages to transfer loads to the central measurement area. Force–displacement curves were measured to derive stress–strain curves for the UHPC component, evaluating the impact of reinforcement rebar and steel fibre content on UHPC’s mechanical response. The analysis revealed that steel fibre volume content significantly influences the tensile response of UHPC reinforcement more than the steel bar diameter and yield strength. Comparing the strain in steel bars to the average strain in reinforced UHPC specimens indicated that post-cracking deformation concentrates at the crack. At the same time, the bond between reinforcement and UHPC remains intact in uncracked sections, allowing effective load transfer. UHPC specimens reinforced with 14 mm diameter steel bars displayed a significant horizontal segment in the descending phase of the stress–strain curve. In contrast, specimens with 18 mm or 22 mm diameter bars exhibit a progressive stress reduction at a nearly constant rate. Stress–strain curves of UHPC were fitted with a five-fold piecewise empirical model applicable to UHPC with a reinforcement ratio higher than 0.09%. The resulting model can be used to model the axial behaviour in UHPC, considering the effects of steel reinforcement.