bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study on the 3D Deformation Behavior of Porous PDMS Flexible Electronic Composite Films Stretched under Different Temperatures
Authors: Chen Cheng , Li Ziyun , Wang Yanlai , Zhang Ze , Ren Chunhua
Published: October 2023

Flexible electronic films need to be applied in different ambient temperatures. The porous substrate of the composite film enhances air permeability. The lifespan of these composite films is significantly affected by variations in temperature and substrate porosity. To explore the impact of temperature and porosity on the performance of composite films, we developed a 3D deformation detection system utilizing the advanced three-dimensional digital image correlation (3D-DIC) method. This system enabled us to observe and analyze the 3D deformation behaviors of porous polydimethylsiloxane (PDMS) flexible composite films when they are subjected to uniaxial stretching at different temperatures. We proposed employing two parameters, namely the strain fluctuation coefficient (M) and off-plane displacement (w), to characterize the 3D deformation of the films. This holistic characterization of deformation through the combined utilization of parameters M and w held greater significance for composite films compared to the conventional practice of solely measuring mechanical properties like the elastic modulus. Through experimental analysis, we discovered that as the temperature increased, the M value of the film decreased while the w value increased for the same stretching distance. Furthermore, the porosity of the composite film depended on the doping mass ratio of PDMS to deionized water during the fabrication process. Specifically, when the ratio was set at 6:1, the composite film exhibited the smallest M value and w value, and the highest air permeability. Additionally, the 3D deformation behavior remained stable across different temperatures for this specific ratio. Moreover, our findings unveiled a remarkable association between the parameter w and the resistance value of the device. These findings provide valuable insights for optimizing the fabrication process of porous PDMS flexible electronic composite films.
A Route to Understanding the Ethane Adsorption Selectivity of the Zeolitic Imidazolate Framework-8 in Ethane–Ethylene Mixtures
Authors: Vargas-Bustamante Jaquebet , Salcedo Roberto , Balmaseda Jorge
Published: October 2023

Ethylene production has a negative environmental impact, with its separation step being one of the major contributors of pollution. This has encouraged the search for energy-efficient alternatives, among which the adsorptive separation of ethane and ethylene stands out. ZIF-8 is a molecular sieve that is potentially useful for this purpose. It is selective to ethane, an exceptional property that remains unexplained. Furthermore, the adsorption of ethane and ethylene above room temperature, such as at steam cracking process outlet temperatures, has not been addressed either. This work aims to fill this knowledge gap by combining experiments at very low volumetric fillings with density–functional theory modelling methods. Adsorption isotherms of ethane and ethylene on ZIF-8 at pressures below 0.3 bar and 311 K, 333 K, and 363 K were measured using zero-length column chromatography. The low-pressure domain of the isotherms contains information on the interactions between the adsorbate molecules and the adsorbent. This favors the understanding of their macroscopic behavior from simulations at the atomic level. The isosteric enthalpy of adsorption of ethane remained constant at approximately −10 kJ/mol. In contrast, the isosteric enthalpy of adsorption of ethylene decreased from −4 kJ/mol to values akin to those of ethane as temperature increased. ZIF-8 selectivity to ethane, estimated from ideal adsorbed solution theory, decreased from 2.8 to 2.0 with increasing pressure up to 0.19 bar. Quantum mechanical modelling suggested that ethylene had minimal interactions with ZIF-8, while ethane formed hydrogen bonds with nitrogen atoms within its structure. The findings of this research are a platform for designing new systems for the adsorptive separation of ethane and ethylene and thus, reducing the environmental impact of ethylene production.
Contribution of Various Loads to the Convex Shape of Rock Wool Insulation Slabs during Production
Authors: Hladnik Jurij , Jerman Boris
Published: October 2023

Rock wool insulation slabs are produced in special curing ovens, where molten rock wool fibres coated with binder are compressed between two slat conveyors and blown with hot air for vitrification. Often, the cross-section of the final slabs is slightly convex, which is undesirable. The degree of convexity depends on the deformation of the steel crossbars of the slat conveyors, which are subjected to combined pressure and nonlinear temperature loadings. Due to this complex loading state, it is difficult to determine the contribution of individual load to the total deformation. The main aim of the study was to determine these contributions. Temperature and stress measurements of the crossbars were performed during rock wool production. Upon collecting these measurements, a finite element (FE) model of a crossbar was established for the identification of the pressure loading acting on the crossbars, and finally for determination of their deformations. As a main result of the study, an inverse problem-based methodology for the identification of the deflection of a structure due to unknown temperature and pressure loadings was established and applied on the specific case. The deviations between the deformations of the FE crossbars and the final shape of the rock wool slabs were below 10%, which validates the novel methodology.
Mesoscopic Analysis of Rounded and Hybrid Aggregates in Recycled Rubber Concrete
Authors: Kamel Mahmoud M. A. , Fu Yu , Feng Xiaowei , Peng Yijiang
Published: October 2023

Recycled rubber concrete (RRC), a sustainable building material, provides a solution to the environmental issues posed by rubber waste. This research introduces a sophisticated hybrid random aggregate model for RRC. The model is established by combining convex polygon aggregates and rounded rubber co-casting schemes with supplemental tools developed in MATLAB and Fortran for processing. Numerical analyses, based on the base force element method (BFEM) of the complementary energy principle, are performed on RRC’s uniaxial tensile and compressive behaviors using the proposed aggregate models. This study identified the interfacial transition zone (ITZ) around the rubber as RRC’s weakest area. Here, cracks originate and progress to the aggregate, leading to widespread cracking. Primary cracks form perpendicular to the load under tension, whereas bifurcated cracks result from compression, echoing conventional concrete’s failure mechanisms. Additionally, the hybrid aggregate model outperformed the rounded aggregate model, exhibiting closer peak strengths and more accurate aggregate shapes. The method’s validity is supported by experimental findings, resulting In detailed stress–strain curves and damage contour diagrams.
Performance Improvement and Microstructure Characterization of Cement-Stabilized Roadbase Materials Containing Phosphogypsum/Recycled Concrete Aggregate
Authors: Wu Yang , Bian Xiaoya , Liu Jie , Chi Ruan , Chen Xuyong
Published: October 2023

The proper reutilization of the phosphogypsum (PG) by-product derived from the production of phosphoric acid and recycled concrete aggregate (RCA) from waste concrete in roadbase materials is of great necessity and importance. This investigation tried seeking a new approach to reuse them to high quality, including turning PG into calcinated PG (CPG) via washing and calcination, as well as adopting sodium metasilicate nonahydrate (SMN) to strengthen the roadbase materials of cement-stabilized CPG and RCA. Upon the mix design, with a series of experiments including unconfined compressive strength, the wet–dry cycle, freeze–thaw cycle, and scanning electron microscopy, the comprehensive effects of PG treatment, the CPG to RCA mix ratio, SMN dosage, wet–dry cycle and freeze–thaw cycle on the road performance of roadbase materials were well evaluated, and the traffic bearing capacity and microstructure characteristics were also analyzed. The results demonstrate that the 7 d unconfined compressive strength of CPG/RCA roadbase materials can reach 5.34 MPa as the CPG and SMN dosage are 20% and 11%, respectively, which meets the requirements of an extremely and very heavy traffic grade. After five wet–dry cycles and freeze–thaw cycles, the resistance of the CPG/RCA roadbase materials to moisture and frost was significantly improved as 11% SMN was added. Meanwhile, SMN contributes to the reduction in crack width and densifies the microstructure of CPG/RCA roadbase materials. The research results can be used to provide new guidance for building more durable roadbase materials.
Study on Porosity of Thermal-Sprayed Commercially Pure Aluminum Coating
Authors: Li Bo , Fan Lei , Bai Jie , He Jinhang , Su Jianfeng , Wang Song , Deng Chao , Liu Shifeng , Zhang Zhiqing
Published: October 2023

Porosity is closely related to the corrosion and wear properties of a coating processed by thermal-spraying technology, and the quantitative characterization of porosity is a crucial part of the research on coating structures. The current image analysis method often uses the mechanical polishing method recommended by ISO to measure a coating porosity. This method has been proved to be an effective method for the characterization of oxide coatings. However, due to the significant differences in the physical and chemical properties between aluminum and oxides, this method may not be suitable for aluminum coatings, and a more appropriate approach needs to be explored. In this paper, the effects of three polishing technologies (mechanical polishing, argon-ion-beam polishing, and electrolytic polishing) on the porosity measurement of pure aluminum coatings were compared and studied. The research results showed that the commonly used mechanical polishing method and more advanced argon-ion-beam polishing method could not completely reveal the pore structure because SiC particles would be embedded in the pure aluminum coatings during mechanical polishing, filling large pores. Although electrolytic polishing technology had advantages in revealing the macroporous structure, it would introduce a microporous structure and oxides, which would affect the measurement of the coating porosity. The composite polishing technology (electrolytic polishing + argon-ion-beam polishing) could perfectly reveal the pore structure in the pure-aluminum coating, and the porosity of arc-sprayed aluminum coating was 9.9%, which was close to the macroscopic true value measured using the weighing method of 10.2%.
Influence of Oil Viscosity on the Tribological Behavior of a Laser-Textured Ti6Al4V Alloy
Authors: Conradi Marjetka , Kocijan Aleksandra , Podgornik Bojan
Published: October 2023

Laser texturing with a dimple pattern was applied to modify a Ti6Al4V alloy at the micro level, aiming to improve its friction and wear resistance in combination with oil lubrication to optimize the performance in demanding industrial environments. The tribological analysis was performed on four different dimple-textured surfaces with varying dimple size and dimple-to-dimple distance and under lubrication with three different oils, i.e., T9, VG46, and VG100, to reflect the oil viscosity’s influence on the friction/wear of the laser-textured Ti6Al4V alloy. The results show that the surfaces with the highest texture density showed the most significant COF reduction of around 10% in a low-viscosity oil (T9). However, in high-viscosity oils (VG46 and VG100), the influence of the laser texturing on the COF was less pronounced. A wear analysis revealed that the laser texturing intensified the abrasive wear, especially on surfaces with a higher texture density. For low-texturing-density surfaces, less wear was observed for low- and medium-viscosity oils (T9 and VG46). For medium-to-high-texturing densities, the high-viscosity oil (VG100) provided the best contact conditions and wear results. Overall, reduced wear, even below the non-texturing case, was observed for sample 50–200 in VG100 lubrication, indicating the combined effect of oil reservoirs and increased oil-film thickness within the dimples due to the high viscosity.
Dextranase Production Using Marine Microbacterium sp. XD05 and Its Application
Authors: Boualis Hind , Wu Xudong , Wang Boyan , Li Qiang , Liu Mingwang , Zhang Lei , Lyu Mingsheng , Wang Shujun
Published: October 2023

Dextranase, also known as glucanase, is a hydrolase enzyme that cleaves α-1,6 glycosidic bonds. In this study, a dextranase-producing strain was isolated from water samples of the Qingdao Sea and identified as Microbacterium sp. This strain was further evaluated for growth conditions, enzyme-producing conditions, enzymatic properties, and hydrolysates. Yeast extract and sodium chloride were found to be the most suitable carbon and nitrogen sources for strain growth, while sucrose and ammonium sodium were found to be suitable carbon and nitrogen sources for fermentation. The optimal pH was 7.5, with a culture temperature of 40 °C and a culture time of 48 h. Dextranase produced by strain XD05 showed good thermal stability at 40 °C by retaining more than 70% relative enzyme activity. The pH stability of the enzyme was better under a weak alkaline condition (pH 6.0–8.0). The addition of NH4+ increased dextranase activity, while Co2+ and Mn2+ had slight inhibitory effects on dextranase activity. In addition, high-performance liquid chromatography showed that dextran is mainly hydrolyzed to maltoheptanose, maltohexanose, maltopentose, and maltootriose. Moreover, it can form corn porous starch. Dextranase can be used in various fields, such as food, medicine, chemical industry, cosmetics, and agriculture.
Metabolomic Phenotype of Hepatic Steatosis and Fibrosis in Mexican Children Living with Obesity
Authors: Garibay-Nieto Nayely , Pedraza-Escudero Karen , Omaña-Guzmán Isabel , Garcés-Hernández María José , Villanueva-Ortega Eréndira , Flores-Torres Mariana , Pérez-Hernández José Luis , León-Hernández Mireya , Laresgoiti-Servitje Estibalitz , Palacios-González Berenice , López-Alvarenga Juan Carlos , Lisker-Melman Mauricio , Vadillo-Ortega Felipe
Published: October 2023

Background and Objectives: Metabolic-dysfunction-associated steatotic liver disease or MASLD is the main cause of chronic liver diseases in children, and it is estimated to affect 35% of children living with obesity. This study aimed to identify metabolic phenotypes associated with two advanced stages of MASLD (hepatic steatosis and hepatic steatosis plus fibrosis) in Mexican children with obesity. Materials and Methods: This is a cross-sectional analysis derived from a randomized clinical trial conducted in children and adolescents with obesity aged 8 to 16 years. Anthropometric and biochemical data were measured, and targeted metabolomic analyses were carried out using mass spectrometry. Liver steatosis and fibrosis were estimated using transient elastography (Fibroscan® Echosens, Paris, France). Three groups were studied: a non-MASLD group, an MASLD group, and a group for MASLD + fibrosis. A partial least squares discriminant analysis (PLS-DA) was performed to identify the discrimination between the study groups and to visualize the differences between their heatmaps; also, Variable Importance Projection (VIP) plots were graphed. A VIP score of >1.5 was considered to establish the importance of metabolites and biochemical parameters that characterized each group. Logistic regression models were constructed considering VIP scores of >1.5, and the receiver operating characteristic (ROC) curves were estimated to evaluate different combinations of variables. Results: The metabolic MASLD phenotype was associated with increased concentrations of ALT and decreased arginine, glycine, and acylcarnitine (AC) AC5:1, while MASLD + fibrosis, an advanced stage of MASLD, was associated with a phenotype characterized by increased concentrations of ALT, proline, and alanine and a decreased Matsuda Index. Conclusions: The metabolic MASLD phenotype changes as this metabolic dysfunction progresses. Understanding metabolic disturbances in MASLD would allow for early identification and the development of intervention strategies focused on limiting the progression of liver damage in children and adolescents.
The Relationship between Serum Selenium Levels and Restless Leg Syndrome in Chronic Kidney Disease Patients
Authors: Tutan Duygu , Ulfberg Jan , Aydemir Nihal , Eser Barış , Doğan İbrahim
Published: October 2023

Background and Objectives: Chronic kidney disease (CKD) is a global public health issue with rising incidence linked to substantial morbidity and mortality. Selenium, an antioxidant trace element, has been linked to low serum levels in end-stage renal disease. Restless Leg Syndrome (RLS), a sleep disorder, is prevalent in CKD patients and significantly impacts their quality of life. The objective of this study was to examine the correlation between serum selenium levels and the prevalence of restless leg syndrome in individuals with chronic kidney disease. Materials and Methods: Forty-six CKD patients undergoing serum selenium level assessments between 1 January 2020 and 28 February 2022, at the Hitit University Faculty of Medicine Department of Nephrology Outpatient Clinic or Hemodialysis Unit, were included. Patients over 18 years of age with no history of hematological or oncological diseases or acute or chronic inflammatory conditions were included in the study groups. Patients taking selenium supplements were excluded. Demographic data, comorbidities, and laboratory values were collected, and RLS presence and severity were evaluated. Statistical analyses include descriptive statistics, correlation analysis, the Mann–Whitney U test, Student’s t test, and Chi-square test. Results: Among the 46 patients, 16 (34.78%) had RLS symptoms. The patient group included 34.78% predialysis, 34.78% peritoneal dialysis, and 30.44% hemodialysis patients, with a median age of 47.98 years. There was no difference in age, gender, and Charlson comorbidity between patients with or without RLS (p = 0.881, p = 0.702, p = 0.650). RLS prevalence varied across CKD subgroups, with hemodialysis patients having a higher prevalence (p = 0.036). Clinical parameters such as blood urea nitrogen, creatinine, calcium, phosphorus, platelet counts, and parathyroid hormone levels exhibited significant differences between patients with and without RLS (p < 0.05). Serum selenium levels were not significantly different between patients with and without RLS (p = 0.327). Conclusions: With an increased comorbidity burden, CKD poses a significant healthcare challenge. When accompanied by RLS, this burden can be debilitating. The difference in CKD stages between groups has shed light on a critical determinant of RLS in this population, emphasizing the role of the chronic kidney disease stage. In our study, serum selenium levels were not associated with the presence and severity of RLS. However, prospective studies with larger numbers of participants are needed to draw a definitive conclusion.
Effect of Pt Addition on the Oxidation and Corrosion Resistance of Al0.25CoCrFeNi High-Entropy Alloy
Authors: Samoilova Olga , Pratskova Svetlana , Suleymanova Ilsiya , Shaburova Nataliya , Ostovari Moghaddam Ahmad , Trofimov Evgeny
Published: October 2023

The effect of minor platinum alloying on the microstructure, phase composition, oxidation and corrosion resistance of Al0.25CoCrFeNi high-entropy alloy (HEA) has been studied. It was observed that Pt does not segregate as a separate phase, but it is incorporated into the fcc solid solution. High-temperature oxidation of the as-cast Al0.25CoCrFeNi and Al0.25CoCrFeNiPt0.1 high-entropy alloys was carried out in a muffle furnace under isothermal conditions at 900 °C for 0–50 h (weighing was carried out every 10 h) in air atmosphere. The specific weight gain decreased from 0.58 mg/cm2 for Al0.25CoCrFeNi to 0.31 mg/cm2 for the platinum-doped Al0.25CoCrFeNiPt0.1 sample. It was determined that Pt triggers the formation of an interlayer Al-rich oxide phase between the outer Cr-rich oxide layer and the interior of the alloy, significantly reducing the oxidation rate of Al0.25CoCrFeNiPt0.1 HEA. Electrochemical tests in 0.5 M H2SO4 solution demonstrated passive behavior with anodic control of the process.
Anisotropic Tensile and Compressive Strengths of Al–4 wt.%Cu Alloy Powder: Part 1—Effects of Compaction Loads and Heat Treatments
Authors: Bonatti Rodrigo S. , Bortolozo Ausdinir D. , Baldo Rodrigo F. G. , Poloni Erik , Osório Wislei R.
Published: October 2023

Powder metallurgy stands out as a preferred manufacturing method across various industries due to its advantages in design flexibility, material efficiency, and cost-effective production. In this work, we study the influence of different compaction directions on the strength characteristics of parts produced using powder metallurgy. Al–4 wt.%Cu alloys are used due to their recyclability. We use three distinctive compaction pressures. After sintering, samples are either air-cooled or water-quenched and naturally aged (T4 temper). Both the compressive and tensile strengths are characterized and thoroughly analyzed. This research highlights the significant impact of both heat treatments and compaction directions on anisotropic strengths. The novelty of this research lies in the use of powders that can be reclaimed from machining, turning, or foundry rejections. By eliminating or minimizing the melting stage and employing powder metallurgy, we achieve cost-effective and environmentally friendly processes. Furthermore, we underscore the critical role played by careful planning of compaction loads, compaction directions, and heat treatments in determining the final mechanical performance. This approach is not only economically viable but also aligns with the growing adoption of environmental, social, and governance (ESG) practices in industry.
Influence of High-Pressure Die Casting Process Parameters on the Compound Strength of Hybrid Components with Undercut Sheet Metal
Authors: Bruckmeier Lukas , Ringel Aron , Vroomen Uwe , Bailly David , Bührig-Polaczek Andreas
Published: October 2023

Reducing the weight of parts through lightweight designs impacts CO2 emissions, especially in the automotive and transportation sectors, which have significant fuel and electric energy consumption. Using multi-material design approaches, specific material properties can be combined to achieve effective lightweighting. Commonly used metals include aluminum, which is known for its high specific strength, and steel, which is valued for its strength and structural integrity. However, joining aluminum and steel presents challenges given their different thermophysical properties and the potential formation of brittle intermetallic phases, making common joining techniques like fusion welding unsuitable. In this study, a hybrid casting process for the production of a complex workpiece from dissimilar materials was investigated. Aluminum was die-cast around a steel sheet insert. Surface structures with undercuts on the steel sheet were applied through modified cold rolling, allowing molten aluminum to flow into the channels and interlock during solidification. It was found that elevated temperatures of the melt and tool were beneficial for the interlocking, resulting in a 30% increase in compound strength. Furthermore, a reduction in both the piston position at the changeover point, between the pre-filling and cavity filling, and the melt velocity at the gate reduced the compound’s strength by 41% and 30%. Up- and downstream processes did not show any significant influence on the conducted experiments. Based on this, two main detrimental effects were observed: pre-solidification of the aluminum melt and gas entrapment.
Advances in Stability of Metallic Implants
Authors: Pan Changjiang , Li Jingan
Published: October 2023

Metallic implants have attracted extensive attention because of their importance in enhancing the quality of human lives and treating human diseases [...]
A New Biomarker Profiling Strategy for Gut Microbiome Research: Valid Association of Metabolites to Metabolism of Microbiota Detected by Non-Targeted Metabolomics in Human Urine
Authors: Zheng Sijia , Zhou Lina , Hoene Miriam , Peter Andreas , Birkenfeld Andreas L. , Weigert Cora , Liu Xinyu , Zhao Xinjie , Xu Guowang , Lehmann Rainer
Published: October 2023

The gut microbiome is of tremendous relevance to human health and disease, so it is a hot topic of omics-driven biomedical research. However, a valid identification of gut microbiota-associated molecules in human blood or urine is difficult to achieve. We hypothesize that bowel evacuation is an easy-to-use approach to reveal such metabolites. A non-targeted and modifying group-assisted metabolomics approach (covering 40 types of modifications) was applied to investigate urine samples collected in two independent experiments at various time points before and after laxative use. Fasting over the same time period served as the control condition. As a result, depletion of the fecal microbiome significantly affected the levels of 331 metabolite ions in urine, including 100 modified metabolites. Dominating modifications were glucuronidations, carboxylations, sulfations, adenine conjugations, butyrylations, malonylations, and acetylations. A total of 32 compounds, including common, but also unexpected fecal microbiota-associated metabolites, were annotated. The applied strategy has potential to generate a microbiome-associated metabolite map (M3) of urine from healthy humans, and presumably also other body fluids. Comparative analyses of M3 vs. disease-related metabolite profiles, or therapy-dependent changes may open promising perspectives for human gut microbiome research and diagnostics beyond analyzing feces.
Assessment of the Nutritional Value of Stems and Leaves of Australian Adzuki Bean
Authors: Johnson Joel B. , Batley Ryan J. , Neupane Pasmita , Bhattarai Surya P. , Trotter Tieneke , Costa Diogo Fleury Azevedo , Naiker Mani
Published: October 2023

Adzuki bean has recently been proposed as a viable dual-purpose (grain-and-graze) crop for the Northern regions of Australia because of its successful use in semi-arid regions and its nitrogen fixation capacity to improve soil fertility and animal nutrition. However, there are very few studies on the phytochemical composition and nutritional value of the non-seed material. This study investigated the phenolic composition of the parts grown in the vegetative phase (leaves and stems) of nine Australian adzuki bean varieties for the first time. The total phenolic content (TPC) of the stem material (157–406 mg GAE/100 g) was 23–217% higher than that of commercial livestock feed, while the TPC of the leaf material (1158–1420 mg GAE/100 g) was 9–11 times higher. Using tandem liquid chromatography mass spectrometry (LC-MS), the major phenolic compounds identified were rutin, luteolin, salicylic acid, and quercetin-3-glucoside. The leaf and stem materials showed high levels of apparent in vitro dry matter digestibility, with no significant difference in total gas or methane production compared to lucerne hay. The results suggest that adzuki bean vegetative materials could be a high-value livestock fodder and support pursuing further in-depth studies into their nutritional value for livestock.
Fabrication of a Highly NO2-Sensitive Gas Sensor Based on a Defective ZnO Nanofilm and Using Electron Beam Lithography
Authors: Feng Zhifu , Giubertoni Damiano , Cian Alessandro , Valt Matteo , Ardit Matteo , Pedrielli Andrea , Vanzetti Lia , Fabbri Barbara , Guidi Vincenzo , Gaiardo Andrea
Published: October 2023

Hazardous substances produced by anthropic activities threaten human health and the green environment. Gas sensors, especially those based on metal oxides, are widely used to monitor toxic gases with low cost and efficient performance. In this study, electron beam lithography with two-step exposure was used to minimize the geometries of the gas sensor hotplate to a submicron size in order to reduce the power consumption, reaching 100 °C with 0.09 W. The sensing capabilities of the ZnO nanofilm against NO2 were optimized by introducing an enrichment of oxygen vacancies through N2 calcination at 650 °C. The presence of oxygen vacancies was proven using EDX and XPS. It was found that oxygen vacancies did not significantly change the crystallographic structure of ZnO, but they significantly improved the electrical conductivity and sensing behaviors of ZnO film toward 5 ppm of dry air.
Experimental Investigation of Electrochemical Capacitive Responses versus Pore Geometries through Artificial Nanotubes
Authors: Dai Jianyou , Xu Minghao , Li Zhangshanhao , Liu Shuoxiang , Wang Yuyao , Shan Lei , Wang Xiaohong , Xu Sixing
Published: October 2023

Electrochemical supercapacitors have attracted significant attention due to their large capacity, high-power output, and long cycle life. However, despite extensive studies and advancements in developing highly porous electrode materials, little quantitative research on the impact of pore geometry on electrochemical responses has been conducted. This paper presents the first quantitative investigation of the relationship between electrochemical capacitive responses and pore geometries at the nanoscale. To achieve this, we constructed a uniform cylindrical pore array with controllable pore diameter and depth by using anodized aluminum oxide (AAO) to serve as a template and atomic layer deposition (ALD) technology for TiN conductive layer decoration. Our findings reveal that, at the nanoscale, increasing the specific surface area through pore diameter and depth does not proportionally increase the capacitive response, even at low scan rates. Meanwhile, we observe a critical pore parameter (170/5000 nm, diameter/depth), where the specific capacitance density and characteristic frequency dramatically decrease with a further increase in the pore aspect ratio. These results indicate that blindly pursuing the absolute specific surface area of the electrode material is not advisable. Instead, optimal pore geometry should be designed based on the desired operational conditions, and this work may serve as valuable guidance.
Characterization of Mechanical Oscillations in Bismuth Selenide Nanowires at Low Temperatures
Authors: Jasulaneca Liga , Poplausks Raimonds , Prikulis Juris , Dzene Elza , Yager Tom , Erts Donats
Published: October 2023

A single transistor preamplifier circuit was designed to facilitate electrical detection of mechanical oscillations in nanoelectromechanical systems (NEMSs) at low temperatures. The amplifier was integrated in the close vicinity of the nanowire inside the cryostat to minimize cabling load and interference. The function of the circuit was impedance conversion for current flow measurements in NEMSs with a high internal resistance. The circuit was tested to operate at temperatures as low as 5 K and demonstrated the ability to detect oscillations in double-clamped bismuth selenide nanowires upon excitation by a 0.1 MHz–10 MHz AC signal applied to a mechanically separated gate electrode. A strong resonance frequency dependency on temperature was observed. A relatively weak shift in the oscillation amplitude and resonance frequency was measured when a DC bias voltage was applied to the gate electrode at a constant temperature.
Investigation of Erase Cycling Induced Joint Dummy Cell Disturbance in Dual-Deck 3D NAND Flash Memory
Authors: You Kaikai , Jin Lei , Jia Jianquan , Huo Zongliang
Published: October 2023

To satisfy the increasing demands for more word-line (WL) layers, the dual-deck even triple-deck architecture has emerged in 3D NAND Flash. However, the new reliability issues that occurred at the joint region of two decks became a severe challenge for developing multiple-deck technology. This work reported an abnormal reliability issue introduced by erasing disturbance of the dummy WLs at the joint region (Joint-DMYs) under multiple cycling. More specifically, after several erase cycling stresses, the increasing joint-DMY’s threshold voltage (Vt) due to the operational stress will finally result in additional disturbance to the adjacent data WLs. In this paper, we proposed this disturbance during erase originates from the backward injected electrons through FN tunneling based on our TCAD simulation result. Moreover, we also proposed an optimal erase scheme to reduce the backward electron injection and suppress the abnormal joint-DMY disturbance during the erase cycling.
Effect of Nanobubbles on the Flotation Behavior of Microfine-Grained Serpentine
Authors: Lu Bingang , Xu Weiguang , Luo Chunhua , Li Wenjuan , Su Xiaohui , Song Yongsheng , Zhou Jianhang , Li Kaiguo
Published: October 2023

At present, scholars mainly study the relationship between nanobubbles and useful minerals, often ignoring the influence of bubbles on fine gangue minerals. When selecting nickel sulfide ore, scholars often faced with mudded and irrepressible serpentine, which seriously affects the quality of the concentrate. This mudded serpentine mineral often enters foam products with bubbles. In this study, the role of nanobubbles in the flotation behavior of hydrophilic serpentine was examined. Nanobubbles were successfully prepared via ultrasonic cavitation, with sizes ranging from 50 to 250 nm. The size and number of bubbles produced at 1 min and 2 min of sonication were significantly better than those of the prolonged test group, and it was found that longer sonication time did not produce better results. The stability of the nanobubbles produced via ultrasound was studied, and it was found that the nanobubbles were stable, with no change in size and only a slight decrease in number as the resting time increased. Nanobubbles were introduced into serpentine flotation, we found that the presence of nanobubbles significantly reduced the flotation recovery of serpentine. The presence of nanobubbles reduced the froth entrainment rate of microfine-grained serpentine, which in turn reduced its flotation rate. In the depressant group trials, it was found that the nanobubbles also reduced the amount of depressant. In short, the presence of nanobubbles can prevent the floating of fine hydrophilic gangues during flotation.
Correlation of Flotation Recoveries and Bubble–Particle Attachment Time for Dodecyl Ammonium Hydrochloride/Frother/Quartz Flotation System
Authors: Batjargal Khandjamts , Güven Onur , Ozdemir Orhan , Boylu Feridun , Pural Yusuf Enes , Çelik Mehmet Sabri
Published: October 2023

Recent studies in the flotation of fine particles have necessitated new techniques and analyses for developing various strategies. Particularly, the improvements in flotation chemistry including the selection of the type of frother, collector, and other reagents have become very significant. In this study, the effect of different commercial polypropylene glycol frothers (PPG200, 400, and 600) in the presence of dodecylammonium hydrochloride (DAH) was investigated for their contribution to flotation recoveries and bubble–particle attachment time values of fine quartz minerals. Zeta potential measurements with DAH were also carried out as a function of pH and reagent concentration to justify the effect of collector usage alone on the charge of particles. A linear increase in flotation recoveries against collector concentration, e.g., 7.4% recovery at 1 × 10−5 mol/L DAH and 65.4% recovery at 1 × 10−3 mol/L DAH, was obtained. In this context, the contribution of frothers was particularly important in that a recovery of 15.91% in the absence of the frother and a modest increase to 19.70% was obtained upon the addition of PPG600 at its critical coalescence concentration (CCC) of 3 ppm. Finally, a strong correlation was found between the bubble–particle attachment time and flotation recovery as a function of collector concentration (lowest attachment time vs. highest flotation recovery). The latter correlation is very promising because bubble attachment time leads to various micro-mechanisms in flotation including bubble film thinning, bubble rupture, and induction time, and consequently, frother efficiency in the presence and absence of a collector. As a result, the experimental findings were gathered to achieve a consistent base for further fundamental studies on the application of the synergistic effect of frothers and collectors in the flotation of fine particles.
Nanohybrid Composites Based on TiO2 and Single-Walled Carbon Nanohorns as Promising Catalysts for Photodegradation of Amoxicillin
Authors: Cercel Radu , Androne Andreea , Florica Cristina Stefania , Lőrinczi Adam , Serbschi Constantin , Baibarac Mihaela
Published: October 2023

In this work, applications of nanohybrid composites based on titanium dioxide (TiO2) with anatase crystallin phase and single-walled carbon nanohorns (SWCNHs) as promising catalysts for the photodegradation of amoxicillin (AMOX) are reported. In this order, TiO2/SWCNH composites were prepared by the solid-state interaction of the two chemical compounds. The increase in the SWCNH concentration in the TiO2/SWCNH composite mass, from 1 wt.% to 5 wt.% and 10 wt.% induces (i) a change in the relative intensity ratio of the Raman lines located at 145 and 1595 cm−1, which are attributed to the Eg(1) vibrational mode of TiO2 and the graphitic structure of SWCNHs; and (ii) a gradual increase in the IR band absorbance at 1735 cm−1 because of the formation of new carboxylic groups on the SWCNHs’ surface. The best photocatalytic properties were obtained for the TiO2/SWCNH composite with a SWCNH concentration of 5 wt.%, when approx. 92.4% of AMOX removal was achieved after 90 min of UV irradiation. The TiO2/SWCNH composite is a more efficient catalyst in AMOX photodegradation than TiO2 as a consequence of the SWCNHs’ presence, which acts as a capture agent for the photogenerated electrons of TiO2 hindering the electron–hole recombination. The high stability of the TiO2/SWCNH composite with a SWCNH concentration of 5 wt.% is proved by the reusing of the catalyst in six photodegradation cycles of the 98.5 μM AMOX solution, when the efficiency decreases from 92.4% up to 78%.
Revisiting Supersaturation of a Biopharmaceutical Classification System IIB Drug: Evaluation via a Multi-Cup Dissolution Approach and Molecular Dynamic Simulation
Authors: Gan Yanxiong , Xu Yaxin , Zhang Xue , Hu Huiling , Xiao Wenke , Yu Zheng , Sun Tao , Zhang Jinming , Wen Chuanbiao , Zheng Shichao
Published: October 2023

As a subclass of the biopharmaceutical classification system (BCS) class II, basic drugs (BCS IIB) exhibit pH-dependent solubility and tend to generate supersaturation in the gastrointestinal tract, leading to less qualified in vitro–in vivo correlation (IVIVC). This study aims to develop a physiologically based multi-cup dissolution approach to improve the evaluation of the supersaturation for a higher quality of IVIVC and preliminarily explores the molecular mechanism of supersaturation and precipitation of ketoconazole affected by Polyvinylpyrrolidone–vinyl acetate copolymer (PVPVA) and hydroxypropyl methyl-cellulose (HPMC). The concentration of ketoconazole in each cup of the dynamic gastrointestinal model (DGIM) was measured using fiber optical probes. Molecular interactions between ketoconazole and PVPVA or HPMC were simulated by Materials Studio. The results demonstrated that PVPVA and HPMC improved and maintained the supersaturation of ketoconazole. PVPVA exhibited superior precipitation inhibitory effect on ketoconazole molecule aggregation due to slightly stronger van der Waals forces as well as unique electrostatic forces, thereby further enhancing in vitro drug absorption, which correlated well with in vivo drug absorption. Compared with a conventional dissolution apparatus paddle method, the DGIM improved the mean prediction error through the IVIVC from 19.30% to 9.96%, reaching the qualification criteria. In conclusion, the physiologically based multi-cup dissolution approach enables improved evaluation of supersaturation in gastrointestinal transportation of BCS IIB drug ketoconazole, enabling screening screen precipitation inhibitors and achieving qualified IVIVC for drug formulation studies.
Synthesis, Crystal Structure, Spectral Characterization and Antifungal Activity of Novel Phenolic Acid Triazole Derivatives
Authors: Xiao Pan-Lei , Song Xiu-Ying , Xiong Xin-Ting , Peng Da-Yong , Nie Xu-Liang
Published: October 2023

At present, phenolic acid derivatives and triazole derivatives have a good antifungal effect, which has attracted widespread attention. A series of novel phenolic acid triazole derivatives were synthesized, and their structures were characterized by IR, MS, NMR, and X-ray crystal diffraction. Compound methyl 4-(2-bromoethoxy)benzoate, methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate, 4-(2-(1H-1,2,4-triazol-1-yl)ethoxy)benzoic acid and 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)-3-methoxybenzoic acid crystallize in the monoclinic system with space group P21/n, the monoclinic system with space group P21, the monoclinic system with space group P21 and the orthorhombic system with space group Pca21, respectively. At a concentration of 100 μg/mL and 200 μg/mL, the antifungal activity against seven plant pathogen fungi was determined. Compound methyl 4-(2-bromoethoxy)benzoate has the best inhibitory effect on Rhizoctonia solani AG1, and the inhibitory rate reached 88.6% at 200 μg/mL. The inhibitory rates of compound methyl 4-(2-(1H-1,2,4-triazol-1-yl) ethoxy)benzoate against Fusarium moniliforme and Sphaeropsis sapinea at a concentration of 200 μg/mL were 76.1% and 75.4%, respectively, which were better than that of carbendazim.
Multifunctional Novel Nanoplatform for Effective Synergistic Chemo-Photodynamic Therapy of Breast Cancer by Enhancing DNA Damage and Disruptions of Its Reparation
Authors: Huang Zheng , Xian Tong , Meng Xiangyi , Hu Huaisong , Gao Lixia , Huang Jiuhong , Yang Donglin , Ou Kepeng , Wang Bochu , Zhang Yimei
Published: October 2023

Photodynamic therapy (PDT) is an effective noninvasive therapeutic strategy that has been widely used for anti-tumor therapy by the generation of excessive highly cytotoxic ROS. However, the poor water solubility of the photosensitizer, reactive oxygen species (ROS) depleting by high concentrations of glutathione (GSH) in the tumor microenvironment and the activation of DNA repair pathways to combat the oxidative damage, will significantly limit the therapeutic effect of PDT. Herein, we developed a photosensitizer prodrug (CSP) by conjugating the photosensitizer pyropheophorbide a (PPa) and the DNA-damaging agent Chlorambucil (Cb) with a GSH-responsive disulfide linkage and demonstrated a multifunctional co-delivery nanoplatform (CSP/Ola nanoparticles (NPs)) together with DSPE-PEG2000 and PARP inhibitor Olaparib (Ola). The CSP/Ola NPs features excellent physiological stability, efficient loading capacity, much better cellular uptake behavior and photodynamic performance. Specifically, the nanoplatform could induce elevated intracellular ROS levels upon the in situ generation of ROS during PDT, and decrease ROS consumption by reducing intracellular GSH level. Moreover, the CSP/Ola NPs could amplify DNA damage by released Cb and inhibit the activation of Poly(ADP-ribose) polymerase (PARP), promote the upregulation of γ-H2AX, thereby blocking the DNA repair pathway to sensitize tumor cells for PDT. In vitro investigations revealed that CSP/Ola NPs showed excellent phototoxicity and the IC50 values of CSP/Ola NPs against MDA-MB-231 breast cancer cells were as low as 0.05–01 μM after PDT. As a consequence, the co-delivery nanoplatform greatly promotes the tumor cell apoptosis and shows a high antitumor performance with combinational chemotherapy and PDT. Overall, this work provides a potential alternative to improve the therapeutic efficiency of triple negative breast cancer cell (TNBC) treatment by synergistically enhancing DNA damage and disrupting DNA damage repair.
Deep Eutectic Solvents Based on Carboxylic Acids and Glycerol or Propylene Glycol as Green Media for Extraction of Bioactive Substances from Chamaenerion angustifolium (L.) Scop.
Authors: Koigerova Alena , Gosteva Alevtina , Samarov Artemiy , Tsvetov Nikita
Published: October 2023

Chamaenerion angustifolium (L.) Scop. is one of the promising sources of biologically active compounds and a valuable industrial crop. Recently, green extraction methods have become more topical. One of them is the application of deep eutectic solvents (DESs). The aim of this work was the synthesis and characterization of DES consisting of glycerin or propylene glycol with malonic, malic, or citric acids, evaluation of their effectiveness for extracting useful substances from C. angustifolium during ultrasonic extraction, description of kinetics, and optimization of extraction conditions. DESs were obtained and characterized with FTIR. Their effectiveness in the process of ultrasound-assisted extraction of biologically active substances from C. angustifolium was estimated. Kinetic parameters describing the dependence of the total phenolic, flavonoids, and antioxidant content, free radical scavenging of DPPH, and concentration of flavonoid aglycons (myricetin, quercetin, and kaempferol) via time in the range of 5–60 min at 45 °C are obtained. Extraction conditions were optimized with the Box–Behnken design of experiment. The results of this work make it possible to expand the scope of DES applications and serve the development of C. angustifolium processing methods.
Investigating the Structural Evolution and Catalytic Activity of c-Co/Co3Mo Electrocatalysts for Alkaline Hydrogen Evolution Reaction
Authors: Chen Long , Jiang Li-Wen , Wang Jian-Jun
Published: October 2023

Transition metal alloys have emerged as promising electrocatalysts due to their ability to modulate key parameters, such as d-band electron filling, Fermi level energy, and interatomic spacing, thereby influencing their affinity towards reaction intermediates. However, the structural stability of alloy electrocatalysts during the alkaline hydrogen evolution reaction (HER) remains a subject of debate. In this study, we systematically investigated the structural evolution and catalytic activity of the c-Co/Co3Mo electrocatalyst under alkaline HER conditions. Our findings reveal that the Co3Mo alloy and H0.9MoO3 exhibit instability during alkaline HER, leading to the breakdown of the crystal structure. As a result, the cubic phase c-Co undergoes a conversion to the hexagonal phase h-Co, which exhibits strong catalytic activity. Additionally, we identified hexagonal phase Co(OH)2 as an intermediate product of this conversion process. Furthermore, we explored the readsorption and surface coordination of the Mo element, which contribute to the enhanced catalytic activity of the c-Co/Co3Mo catalyst in alkaline HER. This work provides valuable insights into the dynamic behavior of alloy-based electrocatalysts, shedding light on their structural stability and catalytic activity during electrochemical reduction processes.