Structural Characteristics Research Articles

Recent Development of Nanozymes for Combating Bacterial Drug Resistance: A Review.

The World Health Organization has warned that without effective action, deaths from drug-resistant bacteria can exceed 10 million annually, making it the leading cause of death. Conventional antibiotics are becoming less effective due to rapid bacterial drug resistance and slowed new antibiotic development, necessitating new strategies. Recently, materials with catalytic/enzymatic properties, known as nanozymes, have been developed, inspired by natural enzymes essential for bacterial eradication. Unlike recent literature reviews that broadly cover nanozyme design and biomedical applications, this review focuses on the latest advancements in nanozymes for combating bacterial drug resistance, emphasizing their design, structural characteristics, applications in combination therapy, and future prospects. This approach aims to promote nanozyme development for combating bacterial drug resistance, especially towards clinical translation.

Structural, vibrational, and luminescent properties of pure and Ce-doped magnesium lithium aluminoborate glass

The objective of this work was to study the properties of new vitreous samples of pure BAlMgLi and Ce-doped BAlMgLi produced by the melt-quenching method. The structural and vibrational characteristics of the samples were analyzed using x-ray diffraction (XRD), vibrational Raman spectroscopy, and vibrational Fourier transform infrared spectroscopy (FTIR). Optically stimulated luminescence (OSL) and thermoluminescence (TL) techniques were also used to identify whether the samples showed a response to ionizing radiation. XRD analyses confirmed the predominance of the amorphous phase of the samples. The Raman spectra revealed that the atomic bonds present in the material matrix are of the pyroborate and metaborate type, enabling stretching vibrations in isolated BO4 and/or Al–O or Al–O–B units. The band at approximately 810 cm−1 is characteristic of the formation of the boroxol ring, indicating that the presence of other elements in the matrix does not affect its glassy characteristics. The FTIR analyses reinforce the results found by Raman spectroscopy, because bands characteristic of low hygroscopic glasses were observed, due to the conversion of BO3 units into BO4 in triborate, tetraborate, and pentaborate groups. This conversion is due to dopant entrainment, which contributes to the high optical transparency of the samples. Their OSL and TL signals were reproducible with intensities dependent on the dopant concentration and radiation dose, with the most intense emissions resulting from 0.5% Ce concentrations.

Analysis of the Sr2GdTi2Nb3O15 ceramic: Investigation into its structural properties and complex impedance spectroscopy

In this study, we successfully synthesized tetragonal tungsten bronze with the nominal formula Sr2GdTi2Nb3O15 and systematically examined of its structure, dielectric, and electrical properties. The material was synthesized through the solid-state reaction technique at a temperature of 1350 °C. The formation of the tetragonal tungsten bronze in the P4/mbm space group was verified via Rietveld refinement using X-ray diffraction data. The electrical characteristics of the ceramic were examined using non-destructive complex impedance spectroscopy (CIS) across a range of frequencies (10–106 Hz) at various temperatures. The real component of impedance (Z') displayed a decrease with rising frequency, suggesting a negative temperature coefficient of resistance (NTCR) for this sample. The Cole-Cole plot of the compound exhibits two semicircles, with the compound's resistance gradually decreasing as the temperature increased. Moreover, the activation energy (Ea) was found to be approximately 0.9 eV, which confirms that oxygen vacancies are responsible for the observed relaxation behavior. Complex modulus analysis confirmed the presence of non-Debye relaxations. These results contribute to a thorough comprehension of the structural and electrical characteristics of Sr2GdTi2Nb3O15, opening avenues for potential applications in diverse electronic devices.

Synthesis and Local Characterization of CoO Nanoparticles in Distinct Phases: Unveiling Polymorphic Structures.

The advancement of functional nanomaterials has become a major focus of recent research, driven by the exceptional properties these materials display compared to their macroscopic (bulk) counterparts. Cobalt oxide nanoparticles (CoO-NPs) stand out primarily for their catalytic and magnetic properties, which can enable a range of technological applications, such as advanced catalysts, drug delivery systems, implants, prosthetics, sensors. However, in addition to the dependence on factors such as size, morphology, and functionalization, the properties of CoO-NPs are significantly influenced by the crystal structure. Therefore, local investigation into the polymorphic structures of CoO at the nanometric scale may provide new insights into the local structural and magnetic characteristics of these systems. In this report, we address the synthesis and local characterization of cobalt oxide (CoO) nanoparticles in the rock-salt cubic fcc-CoO and Wurtzite hpc-CoO phases, obtained through thermal decomposition. We analyze the influence of oleylamine and oleic acid ligands on the structural and morphological control of these systems. The obtained nanoparticles were characterized using conventional techniques such as X-ray diffraction (XRD), transmission electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Local characterization was carried out by the perturbed angular correlation (PAC) nuclear technique using the radioactive tracer 111In(111Cd). Measurements were conducted at 295 and 10 K to investigate possible magnetic phase transitions in these systems. XRD results confirmed the formation of fcc-CoO and hcp-CoO phases. The phase fcc was obtained with the pair of oleylamine and oleic acid ligands, while the phase hcp phase was synthesized using only oleylamine. Additionally, nanoparticles synthesized with oleylamine and oleic acid exhibited better morphological control compared to those produced with only oleylamine. Raman spectroscopy analyses suggest a phase transformation process resulting in Co3O4. PAC results for hyperfine interactions at the 111In(111Cd) probe nucleus, indicate that the hcp-CoO phase shows smaller hyperfine magnetic interactions (B hf = 1 T) compared to the fcc-CoO phase (B hf = 17 T). This suggests the mechanism of superexchange interactions, which are strongly influenced by the Co-O-Co bond angle, which is 110° for the hpc-CoO phase and 180° for the fcc-CoO phase due to the geometries of the systems.

Molecular insights into genistein-NSAID hybrids—synthesis, characterisation and DFT study

AbstractGenistein (GEN) is one of the pharmaceutically valuable phenolic compounds, which belongs to the isoflavone group of flavonoids and is a natural phytohormone found mainly in soybeans and red clover. It affects estrogen receptors, functioning as a selective estrogen receptor modulator (SERM) with anti-inflammatory and antioxidant activity. The presence of reactive phenolic groups in genistein provides an opportunity to expand its structure by introducing components responsible for anti-inflammatory properties. Such an innovative combination of a compound with anticancer and antioxidant potential with an anti-inflammatory compound (NSAID) may lead to interesting new derivatives with dual mechanisms of biological action. The synthesis and characterisation of genistein-NSAID hybrid compounds (ibuprofen, ketoprofen, naproxen, flurbiprofen) was conducted, together with a comprehensive structural and quantum chemistry DFT (density functional theory) computational analysis allowing the description of 1H-NMR and 13C-NMR spectroscopic properties of the starting compounds and the resulting hybrids. The study resulted in the formation of seven hybrid GEN-NSAID derivatives. In the case of ibuprofen, ketoprofen and flurbiprofen, a mixture of isomeric hybrid GEN-4’-NSAID and GEN-7-NSAID derivatives was obtained, whereas, for naproxen, only GEN-4’-NSAID was formed. The structural characteristics of the resulting compounds were determined using MS, IR, 1H-NMR and 13C-NMR spectroscopic methods. The most accurate DFT computational methods for predicting 1H-NMR and 13C-NMR spectra were also established with statistical parameters to assess their accuracy.

The influence of pore throat heterogeneity and fractal characteristics on reservoir quality: A case study of chang 8 member tight sandstones, Ordos Basin

The Chang 8 member of the Yanchang Formation in the Ordos Basin exhibits extensive development of tight sandstone reservoirs. In comparison to conventional reservoirs, these tight sandstone reservoirs demonstrate smaller pore-throat systems and stronger heterogeneity due to interactions between inherent sedimentary components and various diagenetic processes. To further investigate the influence of microscopic pore throat structure on macroscopic physical properties and oil content within the reservoir, a comprehensive study was conducted utilizing high pressure mercury injection, nuclear magnetic resonance, X-CT scanning, and other pore throat testing methods. This study was complemented by observation techniques such as polarizing microscope, scanning electron microscopy, and laser confocal imaging, to study the pore throat system of reservoirs under the influence of different sedimentary components and diagenesis. By comparison, it is observed that the radius of the primary pore throat system in the tight sandstone reservoir ranges from 0.01 to 1 μm. The structural characteristics of the pore throat system significantly impact the macroscopic physical properties of the reservoir. Due to variations in testing methods, high pressure mercury injection, nuclear magnetic resonance (NMR), and X-ray computed tomography (X-CT) reveal different fractal dimensions of the reservoir's pore throat system. Therefore, it is better to respectively utilize fractal dimension Df2, Df2-NMR, Df2-CT, and pore throat parameters to characterize the microscopic pore throat system with a radius ranging from 0.01 to 1 μm. The decrease in the average pore throat radius and the increased irregularity of pore shape contribute to heightened heterogeneity in the micro-pore throat structure within the reservoir. This negatively impacts its physical properties and oil content. Furthermore, it is important to note that the minimum threshold of pore throat radius plays a crucial role as a primary factor determining the fluid seepage capacity within this reservoir. Moreover, when isolated pores exist, reduced fluid mobility ensues, which further worsens the seepage conditions of the reservoir. The chlorite rims development reservoir shows a low fractal dimension in its micro-pore throats, contributing to superior macroscopic petrophysical properties and oil content. However, compression, siliceous cementation, and calcite cementation negatively impact the average pore throat radius by increasing micropores, inaccessible pores, and narrow throat content. This results in a stronger heterogeneity of the pore throat structure, leading to poor seepage conditions and lower oil content.

Avian diversity across guilds in North America versus vegetation structure as measured by the Global Ecosystem Dynamics Investigation (GEDI)

Avian diversity, a key indicator of ecosystem health, is closely related to canopy structure. Most avian diversity models are based on either optical remote sensing or airborne lidar data, but the latter is limited to small study areas. The launch of the Global Ecosystem Dynamics Investigation (GEDI) instrument in 2018 has opened new avenues for exploring the influence of vegetation structure on avian diversity. To examine how direct measurements of canopy structural characteristics explain bird diversity across North America, we analyzed 18 GEDI metrics from 2019 to 2022, along with corresponding Breeding Bird Survey (BBS) counts and AVONET morphological data, analyzing effects across broad regions and at varying spatial extents. We grouped 440 bird species into 20 ecological guilds under six guild categories and employed random forest algorithms to model avian diversity across eight spatial extents (1, 2, 3, 4, 5, 10, 20, and 39.2 km). The models predicted six diversity indices, including species richness (sRich), functional richness (fRich), evenness (fEve), dispersion (fDis), divergence (fDiv), and redundancy (fRed) across eight spatial extents. The best-predicted guilds varied for each diversity index. The most accurate models were sRich (pseudo-R2 = 0.71, RMSE = 4.28) and fRed (pseudo-R2 = 0.60, RMSE = 0.13) for forest specialists guilds; fRich (pseudo-R2 = 0.55, RMSE = 0.18) for urban guilds; fEve (pseudo-R2 = 0.28, RMSE = 0.08) for insectivore guilds; and fDiv (pseudo-R2 = 0.38, RMSE = 0.12) and fDis (pseudo-R2 = 0.53, RMSE = 0.87) for short distance migrants guilds. Our results highlight the critical role of canopy structure, including its horizontal and vertical distribution and variation, in predicting avian diversity, as measured by the mean number of detected modes (num_detectedmodes), the standard deviation of foliage height diversity (FHD), num_detectedmodes, canopy cover, and plant area index (PAI) across the spatial extents centered on BBS routes. Therefore, we recommend incorporating the GEDI metrics into avian diversity modeling and mapping across North America, thereby potentially enhancing bird habitat management and conservation efforts.

Structural and Dynamical Properties of Nucleic Acid Hairpins Implicated in Trinucleotide Repeat Expansion Diseases.

Dynamic mutations in some human genes containing trinucleotide repeats are associated with severe neurodegenerative and neuromuscular disorders-known as Trinucleotide (or Triplet) Repeat Expansion Diseases (TREDs)-which arise when the repeat number of triplets expands beyond a critical threshold. While the mechanisms causing the DNA triplet expansion are complex and remain largely unknown, it is now recognized that the expandable repeats lead to the formation of nucleotide configurations with atypical structural characteristics that play a crucial role in TREDs. These nonstandard nucleic acid forms include single-stranded hairpins, Z-DNA, triplex structures, G-quartets and slipped-stranded duplexes. Of these, hairpin structures are the most prolific and are associated with the largest number of TREDs and have therefore been the focus of recent single-molecule FRET experiments and molecular dynamics investigations. Here, we review the structural and dynamical properties of nucleic acid hairpins that have emerged from these studies and the implications for repeat expansion mechanisms. The focus will be on CAG, GAC, CTG and GTC hairpins and their stems, their atomistic structures, their stability, and the important role played by structural interrupts.

The instability of pectin-based emulsions in the upper digestive tract investigated based on the molecular structure and interfacial properties of pectin

Pectin is a widely used natural emulsifier that is thought to stabilize emulsions in the upper gastrointestinal tract (GIT). However, changes in the structural characteristics and interfacial properties of pectin during its digestive treatment in the upper GIT and the effects on the stability of pectin-based emulsions are still unclear. This study showed that the stability of pectin-based emulsions steadily decreased in the upper GIT. Reductions in the molecular weight of pectin (from 2.74× 105 to 1.61× 105 g/mol) occurred mainly in the stomach, whereas the degree of esterification (from 61.2 % to 42.1 %) decreased throughout the digestive treatment. The change in the structure of pectin reduced its hydrophobicity in the upper GIT, and led to form a cross-linked network with Ca2+ in small intestine rather than adsorbing to the oil-water interface. The behavior was reflected in the increased interfacial tension and the decreases in the interfacial modulus and thickness of pectin. Our insights into the structural characteristics and interfacial properties of pectin and thus into the mechanism of pectin instability in the upper GIT will contribute to the development of more efficient encapsulation methods and improved targeted delivery for active substances or probiotics using pectin-based emulsions.

An Adaptive Chirp Mode Decomposition-Based Method for Modal Identification of Time-Varying Structures

Modal parameters are inherent characteristics of civil structures. Due to the effect of environmental factors and ambient loads, the physical and modal characteristics of a structure tend to change over time. Therefore, the effective identification of time-varying modal parameters has become an essential topic. In this study, an instantaneous modal identification method based on an adaptive chirp mode decomposition (ACMD) technique was proposed. The ACMD technique is highly adaptable and can accurately estimate the instantaneous frequencies of a structure. However, it is important to highlight that an initial frequency value must be selected beforehand in ACMD. If the initial frequency is set incorrectly, the resulting instantaneous frequencies may lack accuracy. To address the aforementioned problem, the Welch power spectrum was initially developed to extract a high-resolution time–frequency distribution from the measured signals. Subsequently, the time–frequency ridge was identified based on the maximum energy position in the time–frequency distribution plot, with the frequencies associated with the time–frequency ridge serving as the initial frequencies. Based on the initial frequencies, the measured signals with multiple degrees of freedom could be decomposed into individual time-varying components with a single degree of freedom. Following that, the instantaneous frequencies of each time-varying component could be calculated directly. Subsequently, a sliding window principal component analysis (PCA) method was introduced to derive instantaneous mode shapes. Finally, vibration data collected under various operational scenarios were used to validate the proposed method. The results demonstrated the effective identification of time-varying modal parameters in real-world civil structures, without missing modes.

Structural characteristics, P-V-L theory, Raman spectra, and microwave dielectric properties of (La1-xNdx)2(Zr0.96Ti0.04)3(MoO4)9 ceramics for LTCC applications

This article explores the microwave dielectric properties of (La1-xNdx)2(Zr0.96Ti0.04)3(MoO4)9 (x=0.1,0.3,0.5, and 0.7) ceramics prepared by solid-state reaction. Utilizing the Rietveld refinement technique in XRD, the sample is identified as a trigonal crystal system belonging to the R3¯c space group. SEM analysis indicates that relative density has a significant impact on the εr and Q×f of ceramics. The Q×f values of ceramics are closely related to the FWHM of the Raman spectra. At 750℃, (La0.5Nd0.5)2(Zr0.96Ti0.04)3(MoO4)9 ceramic exhibited excellent dielectric properties: εr = 10.4 (±0.08), Q×f = 149,300 (±3211) GHz, τf = −34.8 (±0.7) ppm/℃. To gain a deeper understanding of the intrinsic mechanisms governing the microwave dielectric properties of ceramics, analysis based on the P-V-L theory reveals that the La(Nd)-O bond and Mo-O bond contribute significantly to εr and Q×f, respectively.

The collapse of the Ming Dynasty actually began with the Wanli megadrought: Insights from a hydroclimate reconstruction based on tree-ring δ18O over the past 460 years

Climate change has played a pivotal role in shaping Chinese history, especially during the Ming Dynasty. Previous studies have focused primarily on the Chongzhen megadrought, which is widely considered as the primary climatic perturbation behind the demise of the Ming Dynasty. However, relatively little is known about other severe drought events and their potential impact on the dynasty collapse. Additionally, the characteristics of an exceptional climatic anomaly termed the “Late Ming Weak Monsoon Period” are unclear. In this study, we reconstructed the historical variations of Palmer Drought Severity Index for July–September based on tree-ring stable oxygen isotopes (δ18O) from 1556 CE to 2015 CE in southwest Chinese Loess Plateau. Our study reveals a significant weakening of the Asian summer monsoon between 1561 CE and 1661 CE, consistent with the Late Ming Weak Monsoon Period, and unravels its structural characteristics in detail. Our reconstruction also captures a distinct humidification trend over northwest China since the early 2000s. Notably, in addition to the well-known Chongzhen megadrought, our study records the severe Wanli megdrought (1585–1590 CE) during the late Ming Dynasty, an event that rarely featured in earlier studies, exhibiting comparable duration and severity to the Chongzhen megadrought. Further analysis indicates that Wanli megadrought may have served as an early trigger for the collapse of the Ming Dynasty. Furthermore, our analysis implicates the El Niño–Southern Oscillation as a contributing factor in both the Wanli and Chongzhen megadroughts, and thus to the ultimate collapse of the Ming Dynasty by affecting the Asian summer monsoon intensity.

Degradation of thermoplastic polymers for fused filament fabrication under (S)TEM electron beam irradiation

The structural characterization of polymers and, in particular, of those used in Additive Manufacturing (AM) technologies, is essential to improve the understanding of their structure-property relationship for promising high-performance applications. For this, (scanning) transmission electron microscopy-electron energy loss spectroscopy, (S)TEM-EELS is an outstanding tool for exploring materials chemical and structural characteristics at high spatial resolution. However, the high beam-sensitivity of soft materials, such as polymers, hinders the possibility of probing in-depth analysis provided by (S)TEM-EELS. In this work, we analyse the electron beam irradiation damage of four polymers commonly used in Fused Filament Fabrication (FFF), namely polylactic acid (PLA), polycaprolactone (PCL), acrylonitrile butadiene styrene (ABS) and acrylonitrile styrene acrylate (ASA). For this, sequential low-loss and core-loss EEL spectra have been recorded, and the related signals have been monitored as a function of the accumulated dose. Our results show that the critical electron doses using the specimen thickness variations are larger for polymers containing aromatic groups (ABS and ASA) than for aliphatic polymers (PLA and PCL). Regarding the different elements, a larger sensitivity to the electron beam of oxygen regarding carbon and nitrogen is also evidenced. Our results have shown that polymer degradation occurs to a larger extent in the initial steps of electron irradiation, for very low accumulated electron doses, meaning that care should be taken in the selection of the microscopy settings to avoid artefacts produced by the electron beam. Degradation pathways for the four polymers studied are discussed.

Nano-MnOx prepared by redox method for toluene oxidation removal from air

Catalytic oxidation is an efficient VOCs removal technology with great potential and development advantages. The key to the oxidative elimination of VOCs lies in the development and application of the catalyst with high efficiency. In this work, the nano-MnOx catalysts were prepared by redox method and the catalytic oxidation performance of toluene was studied. The calcination temperature could effectively change the surface chemical composition and the nano-MnOx catalyst structures, which could effectively regulate the number of active centers on the catalyst surface to improve the adsorption, activation, and oxidation ability of the nano-MnOx catalysts for toluene molecules. The nano-MnOx catalyst dominated by the MnO2 phase, which was prepared at the calcination temperature of 400 °C, had a high specific surface area, developed porosity, abundant reactive oxygen species, and oxygen vacancies. The structural characteristics are conducive to the adsorption, activation, and oxidation of toluene molecules, and thus exhibited excellent toluene catalytic oxidation activity. At the reaction temperature of 140 °C, the toluene oxidation conversion was as high as 99.4 %, and the toluene conversion remained above 96.6 % after experiencing a 690 min stability test.

Analysis and Experimental Study for Fatigue Performance of Wing-Fuselage Connection Structure for Unmanned Aerial Vehicle

(1) Background: As the principal structural element of an unmanned aerial vehicle (UAV), a lightweight, high-performance wing-fuselage connection structure plays an important role in UAV structural integrity. Previous studies focused on the static strength characteristics of aluminum and high-strength steel wing-fuselage connection structures. With the widespread usage of titanium material in aviation, research should address the fatigue performance of titanium wing-fuselage connection structures. This paper aims to investigate the fatigue performance of the titanium wing-fuselage connection structure by using analysis and experimental methods, and to develop a reliable fatigue assessment method based on the experimental results. (2) Methods: General and detail finite element models were established, and the stress distribution at the detail fatigue design point was obtained via finite element analysis. Based on the equivalent life curve theory, a dimensionless value, detail fatigue value (DF), was proposed to characterize the fatigue performance for structure. By using detail fatigue value (DF) method, the theoretical fatigue performance value was calculated. The fatigue test of the wing-fuselage connection structure was conducted, and the fatigue life was determined according to the test results. (3) Results: For the wing joint with fatigue failure in the test, the test fatigue performance was close to the theoretical value. It can be concluded from the DF value that the analysis and test results are consistent, and the values obtained from the analysis are more conservative than test results. (4) Conclusions: The error between the test DF value and the theoretical analysis DF value is small, and the theoretical analysis of fatigue performance can represent the fatigue characteristics of the wing-fuselage connection structure. The detail fatigue value (DF) method can predict the fatigue performance of the structure quite well.

Comparison of energy absorption characteristics of novel lattice structures inspired by Helleborus petticoat flower and fish scale pattern for different loading orientations

In the present work, arc-shaped, thin-strut-based structures were developed by taking inspiration from the cup shaped Helleborus petticoat flower and fish scale pattern. The designed structures have been additively manufactured with a fused deposition modeling process. In this work, one fish scale pattern inspired structure was developed and named FS structure, whereas two flower-inspired structures were developed and named FL4 and FL8 structures. The static compression tests were conducted to study stress-strain behavior of the proposed structures in two different orientations, viz. orientation:1 (along z-axis) and orientation:2 (along x-axis). Furthermore, the mechanical responses and energy absorption characteristics are comprehensively examined for the proposed structures in both orientations. The structures exhibited higher specific energy absorption (SEA) in orientation:1 compared to orientation:2. The increment in SEA is ∼29 % for FS, ∼298% for FL4, and ∼115% for FL8 structures in orientation:1 compared to orientation:2. Meanwhile, the proposed bio-inspired structures are capable of absorbing energies in the range of 0.06-0.47 MJ/m3, up to densification. Finally, SEA of proposed structures is compared with the SEA of other structures in the available literature.

Experimental Study on the Vibration Characteristics of a Wave-Induced Oscillation Heaving Plate Energy Capture Device

In order to develop green energy, reduce carbon emissions, and alleviate global warming and the green energy crisis, many researchers focus on wave energy, using a device to convert wave energy into electricity. The three main types of wave energy converters are the overtopping type, the oscillating water column type, and the oscillating body type, and for most of them, the power generation efficiency is low. The research team in this paper proposed a wave energy converter for a wave-induced oscillation heave plate. The plate vibrates up and down under the action of waves, and the captured energy of the vibrating plate transfers the energy to the generator, so as to generate electricity. There is electricity only when there is vibration; therefore, the vibration characteristic of the converter is crucial to power generation. So, the vibration characteristics of the energy capture structure of the converter were studied experimentally. The test results show that the energy harvesting device can vibrate, and the vibration effect is good, which further indicates that the device can generate electricity. The effects of different wave conditions and system stiffnesses on amplitude and corresponding amplitude were studied, and the amplitude increases with the increase in wave height and period and decreases with the increase in system stiffness. The amplitude response decreases with the increase in wave height and system stiffness. Under the test conditions, the maximum amplitude of the system is 6.23 cm (when the wave period is 1.40 s, the wave height is 0.25 m, and the system stiffness is 1735.62 N/m), and the maximum amplitude ratio is 0.34 (when the wave period is 1.1 s, the wave height is 0.10 m, and the system stiffness is 1735.62 N/m).

Tailoring polypyrrole morphology and electronic properties through CTAB-SDS self-assembly

This study explores the polymerization of polypyrrole (PPy) within a self-assembled catanionic surfactant composed of cetyltrimethylammonium bromide (CTAB) - sodium dodecyl sulfate (SDS), aiming to control its morphology and electronic properties. The research systematically investigates how varying the compositions of CTAB and SDS surfactants influence the structural and electronic characteristics of PPy. Our findings indicate that the surfactant composition predominantly impacts the shape of PPy rather than its crystallinity. Despite the absence of significant crystallinity, variations in surfactant composition notably alter the electronic properties of PPy. Specifically, an increase in CTAB content results in electrical conductivity increasing from 0.34 to 0.01 S/m. Conversely, higher SDS content enhances the bipolaron-to-polaron ratio, particularly in the C−H deformation region, contributing to improved electronic characteristics. Additionally, packing density analysis reveals that the ordered or disordered acyl chain arrangement within the catanionic surfactant system varies significantly with surfactant composition, further influencing the morphology and electronic properties of PPy. These findings provide valuable pave for designing conductive polymers with tailored electronic properties by a catanionic surfactant, where precise control over such properties is crucial.

Effects of Al doping on structural, optical, morphological, and low-concentration CO2 gas sensing properties of ZnO nanoparticles synthesized by sol-gel method

Abstract This work examines the morphological, structural, optical, and gas-sensing characteristics of ZnO thin films doped with Al that were created by the sol-gel spin coating technique. The thin films, doped with varying aluminum concentrations (0%, 2%, and 5%), were characterized using XRD, UV-visible spectroscopy, and FE-SEM to assess their crystallinity, band gap, and surface morphology. XRD analysis confirmed the incorporation of Al into the ZnO lattice without forming secondary phases, while UV-visible spectroscopy revealed an increase in transmittance and band gap with higher Al doping. FE-SEM images showed a transition from agglomerated grains to smoother surfaces with increased Al content. Gas sensing performance was evaluated using low-concentration CO2 as the target gas. The results demonstrated that Al doping significantly enhances the CO2 sensing response, with the 5% Al-doped ZnO exhibiting the highest sensitivity due to increased carrier concentration and improved surface interaction. These findings suggest that Al-doped ZnO thin films are promising candidates for efficient CO2 gas sensors, combining enhanced structural and optical properties with superior gas sensing capabilities.

Quantum computational and experimental spectroscopic investigation (FT-IR, Raman, UV–Vis), PES, LHE and topological investigations of 7-[(2R)-2-hydroxypropyl]-1,3-dimethylpurine-2,6-dione

The current research explored the structural optimization, electrical and vibrational characteristics, and quantum chemical calculations via the procedure of DFT for a purine derivative, 7-[(2R)-2-hydroxypropyl]-1,3-dimethylpurine-2,6-dione (2HDPD). Functional groups were found by correlating FT-IR with simulated spectra. TD-DFT calculations were done for UV–vis absorption and to ascertain the electronic properties of both the solvent and the gas phase, enabling additional study of the compounds LHE. The experimental outcomes and theoretic parameters are in good agreement. LUMO and HOMO band gaps spectacle that the molecule is chemically reactive and that there is adequate charge transfer. Polar solvent exhibits the highest band gap value, 5.057 eV. Numerous topological considerations were accomplished using the Multiwfn tool. Charge transfer investigations have demonstrated the most imperative states. Weak intermolecular interactions were investigated using RDG analysis, LOL, NBO, and ELF. The 2HDPD compounds reactive areas were discovered by applying the MEP and Fukui investigations. Hyperpolarizability characteristics were used to calculate NLO behavior. The drug-like characteristics of the molecule follow Lipinski five rules. After docking with the proteins 1NG2, 2DVV, 3CAF, and 7OEX, the compound 2HDPD showed moderate binding affinities of −5.28, −5.04, −4.96, and −5.66 kcal/mol, in that order. The Ramachandran plot verified the proteins stability and advantageous locations. The Docking results show compound 2HDPD exhibited a COPD property.