Structural Disorder Research Articles

A prospective study of associations between accelerated biological aging and twenty musculoskeletal disorders

BackgroundMusculoskeletal disorders pose major public health challenges, and accelerated biological aging may increase their risk. This study investigates the association between biological aging and musculoskeletal disorders, with a focus on sex-related differences.MethodsWe analyzed data from 172,332 UK Biobank participants (mean age of 56.03 ± 8.10 years). Biological age was calculated using the KDM-BA and PhenoAge algorithms based on blood biomarkers. Musculoskeletal disorders were diagnosed using the ICD-10 criteria, with sample sizes ranging from 1,182 to 23,668. Logistic regression assessed cross-sectional associations between age acceleration (AA) metrics and musculoskeletal disorders. Accelerated Failure Time (AFT) model was used for survival analysis to evaluate the relationships between AAs and musculoskeletal disorders onset. Models were adjusted for demographic, lifestyle, and socio-economic covariates. The threshold of P-values were set by the Holm-Bonferroni correction.ResultsCross-sectional analyses reveal significant associations between AAs and fourteen musculoskeletal disorders. Survival analyses indicate that AAs significantly accelerate the onset of nine musculoskeletal disorders, including inflammatory polyarthropathies (RTKDM-BA = 0.993; RTPhenoAge = 0.983), systemic connective tissue disorders (RTKDM-BA = 0.987; RTPhenoAge = 0.980), spondylopathies (RTPhenoAge= 0.994), disorders of bone density and structure (RTPhenoAge= 0.991), gout (RTPhenoAge= 0.968), arthritis (RTPhenoAge= 0.991), pain in joint (RTPhenoAge= 0.989), low back pain (RTPhenoAge= 0.986), and osteoporosis (RTPhenoAge= 0.994). Sensitivity analyses are consistent with the primary findings. Sex-specific variations are observed, with AAs accelerating spondylopathies, arthritis, and low back pain in females, while osteoporosis is accelerated in males.ConclusionAccelerated biological aging is significantly associated with the incidence of several musculoskeletal disorders. These insights highlight the importance of biological age assessments in gauging musculoskeletal disorder risk, aiding early detection, prevention, and management.

The Effect of Nitrogen as a Co-Dopant in p-Type NiO:Nb Films on the Photovoltaic Performance of NiO/TiO2 Transparent Solar Cells

Doping engineering has been applied in niobium-doped NiO (NiO:Nb) by adding nitrogen (N) in its structure. The rf-sputtered films were made from a Ni-Nb composite target on unheated substrates at 300 W rf power and 5 mTorr total pressure. The plasma contained 50% Ar and 50% O2 for the fabrication of the single-doped NiO:Nb film (AΝ film), and N2 gas for the incorporation of N in the Ni-O-Nb structure. The N2 in plasma was introduced by keeping constant the flow rates of O2 and N2 gasses (O2/N2 = 1) and reducing the amount of Ar gas, namely 94% Ar, 3% O2, and 3% N2 (film AN1); 50% Ar, 25% O2, and 25% N2 (film AN2); and 6% Ar, 47% O2, and 47% N2 (film AN3). All films had the single phase of cubic NiO and both Nb and N in the Ni-O structure were revealed by XPS experiments. The roughness of the films was increased with the increase in N in plasma. Post-deposition thermal treatment improved the crystallinity and reduced the structural disorder of the films. The AN2 film was found to be the most transparent of all films, exhibiting the widest band gap, 3.72 eV, and the narrowest Urbach tail states’ width, 313 meV. The AN and the AN2 films were employed to form NiO/TiO2 heterostructures. The NiO:Nb/TiO2 and NiO:(Nb,N)/TiO2 heterostructures exhibited a visible transmittance of around 42% and 75%, respectively, and both showed rectification properties. Upon illumination with UV light, the NiO:(Nb,N)/TiO2 diode exhibited enhanced photovoltaic performance when compared to the NiO:Nb/TiO2 solar cell: the short-circuit current densities were 0.2 mA/cm2 versus 1.4 μA/cm2 and the open-circuit voltages were 0.5 V versus 0.2 V. The output characteristics of the p-NiO:(Nb,N)/n-TiO2 UV photovoltaics can be further improved by proper engineering of the individual layers and device processing procedures.

Hypoxic brain damage in Methadone misuse: insights from MRI imaging and comparative study.

This study aimed to investigate the potential presence of brain disorders, particularly hypoxia, via magnetic resonance imaging (MRI) in patients misusing methadone, with a comparison to regular opium users and a control group. Conducted as a cross-sectional comparative study at Kamali Hospital in Karaj, Iran, the research included male participants comprising methadone users, opium users, and controls. Inclusion criteria were stringent, focusing on substance use duration and absence of brain structural disorders. MRI scans were performed using a 1.5T MRI scanner. Qualitative MRI assessments and chi-square tests analyzed associations between substance use and hypoxia, while logistic regression examined potential confounding variables. Significant hypoxia was observed in the methadone group (16.7%, 5/24; p = 0.00057), with no cases in the opium or control groups. Logistic regression analysis showed no significant predictors of hypoxia regarding dose and duration of use. MRI findings in methadone users with hypoxia included varied ADC intensities, high signal intensities on T2-weighted and diffusion-weighted imaging (DWI) sequences, and angiogenesis patterns on TOF sequences. The co-use of methadone and alcohol was noted in three of the five hypoxia cases. Methadone misuse, particularly with alcohol, poses a significant risk of hypoxia, detectable via MRI. This study underscores the need for routine MRI monitoring, stricter regulation of non-prescribed methadone, and enhanced public health education to mitigate misuse risks. Future research should expand sample sizes and incorporate advanced imaging techniques to further elucidate methadone's neurological impact.

Reevaluation of the Suitability of 129Xe Nuclear Magnetic Resonance Spectroscopy for Pore Size Determination in Porous Carbon Materials.

Xenon isotope nuclear magnetic resonance (129Xe-NMR) spectroscopy has been widely used to evaluate the pore structure of materials. However, determining how to apply this technique to investigate porous carbon materials is sometimes challenging, partly due to the structural disorder and heterogeneity of the surface properties of these materials, and partly due to the lack of reliable methods for controlling and assessing the density of adsorbed Xe. In this study, we designed and constructed a temperature- and pressure-controllable 129Xe-NMR system to evaluate the interaction between activated carbon (AC) and adsorbed Xe molecules. Based on a confirmation of surface-covering adsorption form of Xe molecules in AC pores, the extrapolation to the ordinate in plots of the surface area-normalized Xe adsorption amount (ρXe) and measured 129Xe-NMR chemical shifts of adsorbed Xe molecules, δ(Xe), to remove the influence of the Xe-Xe interaction allowed us to estimate the interaction between the AC pore surface and a single Xe molecule. These data confirmed that interactions between the pore surface and adsorbed Xe molecules depend on a parameter related to the AC pore size, regardless of the content of oxygen-containing surface functional groups, and an empirical equation to estimate the average pore size of ACs from the 129Xe-NMR results was proposed. Downward deviations of the linear correlation between ρXe and δ(Xe) were attributed to the influence of paramagnetism presumably derived from oxygen-containing functional groups on the surfaces of ACs and to changes in the adsorption form in low- and high-ρXe regions, respectively. These findings confirm the suitability of 129Xe NMR for pore size determination in porous carbon materials.

Electronic properties of polyaniline–graphene nanocomposites synthesized via solution mixing method

A key advantage of combining the exceptional properties of graphene with conducting polymers, lies in their remarkable property tunability through filler additions into polymer matrices, with synthesis routes playing a crucial role in shaping their characteristics. In this work, we examine the electronic properties of polyaniline and graphene nanocomposites synthesized via a simple solution mixing method, which offers advantages such as ease of use and efficiency. Increasing graphene content enhances nanocomposite conductivity, and a percolation effect is observed. The percolation threshold is high and is consistent with a strong role played by voids in the structure. Temperature-dependent conductivity measurements highlight three distinct conduction regimes: insulating, critical, and metallic. These findings underscore the significant influence of synthesis method and structural disorder on shaping electronic properties, paving the way for engineering multifunctional nanocomposites with exceptional versatility and performance.

Einstein frequency of individual chalcogen bonds in Cu(In,Ga)Se2 and Cu(In,Ga)S2: Indicator of diffusion property of Cu, In, and Ga atoms

Elucidating the characteristics of the Cu-Se, In-Se, and Ga-Se bonds in chalcopyrite-type Cu(In,Ga)Se2-based semiconductors can aid the design and fabrication of highly efficient thin-film photovoltaic devices. In this study, we used extended X-ray absorption fine structure (EXAFS) analyses to evaluate the characteristics of chemical bonds in Cu(In,Ga)Se2 and Cu(In,Ga)S2 powder samples at low temperatures (10–300 K). The temperature dependence of the structural and vibrational disorder (Debye–Waller factor) provides the Einstein temperature of an individual bond in Cu(In,Ga)Se2-based materials. The analyzed Einstein temperature, which is proportional to the Einstein frequency, increased in the order of Cu–Se(S) < In–Se(S) ≤ Ga–Se(S), and the S-containing bond had a higher Einstein temperature than the corresponding Se-containing one. We also analyzed the effect of the Ga/(Ga + In) ratio on the Einstein temperature of each chemical bond. The force constant of the oscillator (i.e., the bond) was determined from the Einstein frequency using the reduced mass of the constituent atoms. The obtained bond properties were found to correlate with the diffusion characteristics of the constituent atoms in CuInSe2-based solar cell materials.

Challenges and Strategies for Continuous Cropping of Morchella spp.: A Review

Continuous cropping obstacles (CCOs) have increasingly become an important phenomenon affecting morel mushroom yield and quality. In this review, we summarize the current knowledge about the driving factors behind morel mushroom continuous cropping, including the increase in soil nutrients, disorder of the soil microbial structure, aggravation of diseases, and accumulation of allelochemicals and autotoxins. Furthermore, we analyze the interrelationships among these driving factors. To mitigate these adverse effects, we propose five potential strategic approaches aimed at optimizing existing interventions. This overview not only delineates the causative agents and their intricate interactions under continuous cropping scenarios but also consolidates prospective solutions to alleviate these constraints, thereby advancing our understanding and management of morel production sustainability.

Active doping controls the mode of failure in dense colloidal gels

Mechanical properties of disordered materials are governed by their underlying free energy landscape. In contrast to external fields, embedding a small fraction of active particles within a disordered material generates nonequilibrium internal fields, which can help to circumvent kinetic barriers and modulate the free energy landscape. In this work, we investigate through computer simulations how the activity of active particles alters the mechanical response of deeply annealed polydisperse colloidal gels. We show that the "swim force" generated by the embedded active particles is responsible for determining the mode of mechanical failure, i.e., brittle vs. ductile. We find, and theoretically justify, that at a critical swim force the mechanical properties of the gel decrease abruptly, signaling a change in the mode of mechanical failure. The weakening of the elastic modulus above the critical swim force results from the change in gel porosity and distribution of attractive forces among gel particles, while below the critical swim force, the ductility enhancement is caused by an increase of gel structural disorder. Above the critical swim force, the gel develops a pronounced heterogeneous structure characterized by multiple pore spaces, and the mechanical response is controlled by dynamical heterogeneities. We contrast these results with those of a simulated monodisperse gel that exhibits a nonmonotonic trend of ductility modulation with increasing swim force, revealing a complex interplay between the gel energy landscape and embedded activity.

КОРРЕКЦИЯ МИТОХОНДРИАЛЬНОЙ ДИСФУНКЦИИ ПРИ КОМБИНИРОВАННОМ ПРИМЕНЕНИИ ПРЕПАРАТОВ МЕТРОГИЛ И АИКАР В ЭКСПЕРИМЕНТАЛЬНОЙ МОДЕЛИ ПАРОДОНТИТА

Background: It is known that mitochondrial dysfunction is involved in the pathogenesis and progression of periodontitis, affecting oxidative stress and regulating inflammatory reactions. Therefore, in recent years, research on mitochondria-directed therapeutic approach to periodontal tissue diseases has been rapidly growing. AIM: Evaluate the effect of the drugs Metrogyl and Aicar on structural and functional disorders in the mitochondria of periodontal tissues in an experimental model of periodontitis in laboratory rats. Materials and methods: Male white Wistar rats weighing 221 ± 7.5 g at the age of 4 months were used in this work. The animals were divided by simple randomization into four groups, 10 animals in each: Group 1 – intact (control group); Group 2 – rats with modeled periodontitis; Group 3 – rats with modeled periodontitis and the use of Metrogyl; Group 4 – rats with modeled periodontitis and combined use of Metrogyl and Aicar. Experimental periodontitis (EP) in rats was modeled by the ligature method by suturing a polyfilament non-absorbable thread into the gum in the area of the lower incisors. The following molecular genetic and biochemical parameters were used: damage to nuclear DNA (nDNA) and mitochondrial DNA (mtDNA), mtDNA copy number and the level of heteroplasmy, as well as the levels of malondialdehyde (MDA) and reduced glutathione (GSH). Results: The data from this study showed that on the 14th day after ligation, animals in the periodontal tissue have an increased level of damage and mtDNA heteroplasmy, compared to the control group. The same animals showed a decrease in the GSH level, while the MDA level was increased compared to the control animals. In other groups of rats with EP, the modulation of these damages was assessed using Metrogyl, as well as the combined use of Metrogyl and Aicar. It was shown that for all the parameters studied, the combined use of Metrogyl and Aicar led to a more effective reduction in mitochondrial disorders, compared to the group of rats that received only Metrogyl. Conclusions: The combined use of Metrogyl and Aicar drugs had a more effective effect on reducing mitochondrial dysfunction in periodontal tissue in rats with EP, in contrast to the group in which only Metrogyl was used. Thus, the use of traditional drugs in combination with mitochondria-targeted compounds that reduce oxidative stress may serve as a new therapeutic approach to various periodontal tissue diseases.

Simultaneous structure and surface engineering of metal-organic framework derived LiNi0.5-xFe2xMn1.5-xO4 cathode material for improving high voltage performance of lithium-ion batteries

This study presents a novel material synthesis approach utilizing a terephthalic acid-based metal-organic framework as a precursor and employing an ethanol-assisted hydrothermal treatment to produce high-performance Fe-doped LiNi0.5Mn1.5O4 (LNMO) cathode material. This strategy yields a well-crystallized spinel structure with uniformly distributed transition metal ions. Additionally, the appropriate quantity of Fe dopant can achieve the desired Mn3+/Mn4+ ratio, level of structural disordering, and crystal phase purity for Fe-doped LNMO. The synthesis process also aids in forming an amorphous Li2CO3 surface layer, approximately 1 nm thick, which protects the active material from excessive reaction with electrolyte. The typical Fe-doped LNMO cathode (S-05) exhibits superior performance compared to a commercialized LNMO counterpart. It delivers an initial discharge capacity of 135 mAh g-1 at 1 C with exceptional cycling stability over 500 cycles (capacity retention of 90%) under high voltage (5.0 V vs. Li+/Li). Furthermore, its rate capability significantly improves, with a capacity retention of 85% (5 C/0.2 C). This enhanced performance aligns with evidence of activated Ni2+/Ni3+/Ni4+ redox reactions and suppressed cathode electrolyte interphase resistance, leading to promoted Li+ diffusion. Moreover, it is found the cathode helps alleviate electrolyte degradation at high voltages by inhibiting the formation of singlet oxygen in the electrolyte.

Electrical, Optical & Structural characteristics of reduced graphene oxide: A comparative analysis using different reducing agents

The study of optical and electrical properties of functionalised materials of GO and rGO are crucial for their different applications in energy storage, optoelectronics and biosensing. The structural disorder occurring during the synthesis process largely affects the optical properties of the materials. In this work we have tried to study the variation in optical and electrical properties of rGO by varying the synthesis parameters. Different rGO samples prepared from the same precursor (graphite powder) by using various reducing agents are studied. It is observed that the physical conditions during the synthesis process affect the bandgap of the synthesised samples. This study is correlated with the elemental analysis, surface morphology and defect studies.

Quasi-1D, rectangular-like and hexagonal moiré superlattices in exfoliated highly oriented pyrolytic graphite

Understanding the dynamics of structural collapse in hexagonal moiré superlattices is of importance towards the stabilization of exotic superconductive phenomena in quasi-1D superlattices. Here we investigate unusual exfoliation-induced structural transformations of hexagonal moiré superlattices, in a μm-thin lamella of highly oriented pyrolytic graphite (HOPG). By employing a combination of experimental techniques, namely transmission electron microscopy (TEM), high resolution TEM (HRTEM) and selective area electron diffraction (SAED) we systematically investigate the collapse of hexagonal moiré superlattices into rectangular-like and quasi-1D superlattices in an exfoliated lamella. Interestingly, the rectangular-like lattice reveals perpendicular super-periodicities D1 ~ 17 nm and D2 ~ 9 nm. The width of the quasi-1D channels was found to vary from ~5 nm to ~13 nm, with a super-periodicity D ~ 3 nm. Most importantly, systematic SAED acquisitions reveal a splitting of the electron diffraction signals into multiple components, consisting of doubled and tripled diffraction rings. We interpret these as a clear indicator of structural disorder which results from an interplay of exfoliation-induced structural transitions, namely interlayer-sliding, local layer-rotation (twisting) and significant wrinkling (strain) effects.

Tunable nonlinear optical properties in polyaniline-multiwalled carbon nanotube (PANI-MWCNT) system probed under pulsed Nd:YAG laser

The investigation of the nonlinear optical (NLO) properties of polyaniline (PANI) and polyaniline doped with multi-walled carbon nanotube (PANI-MWCNT) in both solution and film forms was conducted using the open-aperture z-scan approach. A Q-switched resonant Nd: YAG laser with a wavelength of 532nm and two different fluences was utilized in this study. Based on the z-scan experiments, it was observed that the NLO behaviour of PANI and PANI-MWCNT composites exhibited a transition from reverse saturable absorption (RSA) to saturable absorption (SA) when the samples changed from a liquid to a film state. Two photon absorption (TPA) and thermally induced nonlinear scattering are the main mechanisms behind the RSA behaviour of the materials in solution form. The reason for SA behaviour of these materials in film form is attributed as the ground-state free electron bleaching in the conduction band due to the increased laser intensity. Due to increased structural disorder and the defect states or trap levels created by the dopants in the PANI system, the NLO properties of the PANI-MWCNT composite in both solution and film forms have significantly improved compared to those of pure PANI. Urbach tail analysis and carbon cluster determination revealed the presence of defect states in the composites system. The composite between PANI and MWCNT was verified using Fourier transform infrared (FTIR) spectroscopy. The functional elements present in the composites are verified by X-ray photoelectron spectroscopy. The NLO parameters of the samples, viz., the nonlinear absorption coefficient (β), the imaginary part of the nonlinear, and susceptibility χi(3) the figure of merit (FOM) of PANI-MWCNT, exhibited a notable enhancement in their values over PANI. Moreover, the PANI-MWCNT film demonstrated superior SA performance and the PANI-MWCNT solution demonstrated better OL performance compared to that of the PANI film and solution respectively. Also the effects of dopant induced structural modifications and lattice disorder on the NLO behaviour of these materials are correlated with the obtained NLO parameters. The tunable NLO properties accomplished by controlling the structural phase and dopant-induced defects enhance the possibility of these nanostructures for applications in optical limiting, optical switching, optical modulation, optical pulse compression and laser pulse narrowing.

Investigation of physical properties of Mn doped lead phosphate glasses

Mn doped lead phosphate glasses (MnLPG) as (40-x)%P2O5-40 % PbO-16.5%Na2O-3.5%Al2O3-xMnO2 (x = 0, 1, 2, 3 and 4 %) matrix system are prepared by the melt-quenching method. The physical properties have been performed using several techniques such as X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform InfraRed spectroscopy (FTIR), Raman spectroscopy, UV–Visible properties, photoluminescence (PL) and EPR (electron paramagnetic resonance). XRD confirms the amorphous character of the glasses. DSC reveals an improvement of the glass transition temperature Tg values by increasing the density ρ and the oxygen packing density OPD and decreasing the molar volume Vm which leads to have a network glass more compact and tightly packed and reticulates the phosphate groups. The Infrared and Raman results show an opposite behaviour with a broken of the phosphate structure and the disruption of the P–O–P linkages. The optical spectra present absorption bands characteristic of Mn3+ and Mn2+ ions octahedral transition. Mott and Davis model presents a decrease of the band gap energy winth the MnO2 addition. The Urbach energy ΔEurb shows an increase with increase of manganese amount which is related to the increase of the structural disorder degree as the rate of manganese increases. The EPR spectrum of the 4 % Mn doped glass is characterized by a strong resonance signal centered at g near 2.0 another weak signal at g∼4.3 with no hyperfine structure. PL spectra exhibit emission bands corresponded to the oxygen defects presented in the glass and the appearance of a new band assigned to the Mn2+ ions as high as Mn increases.

Machine‐Learning‐Assisted Process Optimization for High‐Performance Organic Thermoelectrics

AbstractOptimizing the processing conditions of conjugated polymers is a key step in improving the performance of various organic electronic devices, including organic thermoelectric (TE) devices that are capable of harvesting energy from waste heat. However, the inherent structural and energetic disorders in these materials and their unpredictable property changes after processing complicate the optimization principles, requiring numerous trial‐and‐error experiments to maximize the TE performance. Here, a machine‐learning (ML)‐based design of experiments approach is introduced to address these challenges, and its effectiveness is demonstrated using a representative thiophene‐based doped polymer system for organic TE. This approach not only helps to quantitatively understand how each processing parameter affects the TE properties of the polymer but also facilitates the prediction of optimal processing conditions, leading to achieve maximum TE performance with minimal experiments within a large parameter space. Furthermore, the ML‐based approach is validated by revealing the origins of the power factor maximization at the ML‐predicted processing conditions through analysis of the morphology and electronic states of the doped polymer films. The proposed methodology is applicable to the majority of polymer systems for organic thermoelectric energy conversion and will provide guidelines for determining optimal process conditions and improving TE performance with minimal effort.

Taraxasterol Acetate From Taraxacum officinale Ameliorates Dextran Sulfate Sodium–Induced Ulcerative Colitis in Mice in Association With Changes of the Metabolism and Structure of Gut Microbiota

ABSTRACTUlcerative colitis (UC) is closely associated with the structural and metabolic disorders of gut microbiota. Taraxasterol acetate (TSA) from Taraxacum officinale (TO) has anti‐inflammatory activity. In this study, to investigate the therapeutic potential of TSA and its mechanism of action in dextran sulfate sodium (DSS)‐induced UC. The anti‐inflammatory effects of TSA were evaluated in vitro. DSS‐induced UC animal models and TSA gavage were employed for in vivo experiments. The results indicated that TSA showed good anti‐inflammatory effects both in vitro and in vivo, and the anti‐UC effect of TSA was better than that of the extract in vivo. TSA relieved clinical symptoms in DSS‐induced UC mice and repaired the intestinal barrier. TSA restored the structural disorder of gut microbiota and regulated metabolic levels in DSS‐induced UC mice. This study provides a fresh perspective on developing new therapeutic methods against UC using the traditional Chinese medicine TSA.

Global analysis of endogenous protein disorder in cells.

Disorder and flexibility in protein structures are essential for biological function but can also contribute to diseases, such as neurodegenerative disorders. However, characterizing protein folding on a proteome-wide scale within biological matrices remains challenging. Here we present a method using a bifunctional chemical probe, named TME, to capture in situ, enrich and quantify endogenous protein disorder in cells. TME exhibits a fluorescence turn-on effect upon selective conjugation with proteins with free cysteines in surface-exposed and flexible environments-a distinctive signature of protein disorder. Using an affinity-based proteomic approach, we identify both basal disordered proteins and those whose folding status changes under stress, with coverage to proteins even of low abundance. In lymphoblastoid cells from individuals with Parkinson's disease and healthy controls, our TME-based strategy distinguishes the two groups more effectively than lysate profiling methods. High-throughput TME fluorescence and proteomics further reveal a universal cellular quality-control mechanism in which cells adapt to proteostatic stress by adopting aggregation-prone distributions and sequestering disordered proteins, as illustrated in Huntington's disease cell models.

Tailoring glass characteristics: Unveiling the impact of PbO and ZnO in Titanium-Barium borate glasses for advanced radiation protection

This study focused on synthesizing glasses with the formula (70-x-y)B2O3-20BaO-10TiO2-xZnO-yPbO (where x = y = 5, 10, 15, and 20 mol %) using the melt-quenching approach and examined the impact of ZnO and PbO substitution on the mechanical, optical, and radiation shielding properties of these glasses. The mechanical moduli and micro-hardness decreased with higher ZnO and PbO concentrations, indicating reduced rigidity and elasticity. Optical analyses demonstrated that as ZnO and PbO contents increased, the absorption edge shifted to longer wavelengths, and the optical band gap (Eg) decreased. Furthermore, Urbach energy (EU) values increased from 0.212 to 0.431 eV, indicating a higher degree of structural disorder. Radiation shielding studies revealed that glasses with higher concentrations of ZnO and PbO demonstrated enhanced shielding capabilities. Among the glasses prepared, the sample with the composition 30B2O3 + 20BaO + 10TiO2 + 20ZnO + 20PbO exhibited the best performance, characterized by a high mass attenuation coefficient (MAC) and linear attenuation coefficient (LAC).

Enhancing photocatalytic performance in Bi₂WO₆ nanolayers via ultrasound-assisted oxygen vacancy engineering

High-quality two-dimensional Bi₂WO₆ nanolayers were synthesized via hydrothermal processes, with oxygen vacancies introduced through an ultrasound-assisted alkali etching treatment. Comprehensive characterization using Raman spectroscopy, X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and positron annihilation spectroscopy (PAS) confirmed the presence and effects of these vacancies on the structural and electronic properties of the nanolayers. Raman spectroscopy revealed shifts in vibrational modes, particularly a blue shift in the WO₆ octahedral vibration modes, indicative of oxygen vacancy formation. XPS analysis showed a reduction in the binding energies of the Bi 4f and W 4f orbitals, confirming an altered electronic environment. TEM images demonstrated significant lattice distortions in the oxygen-vacancy-rich regions, particularly disordered WO₆ octahedra and disrupted BiO bond lengths. These distortions are consistent with the structural disorder observed in XAS measurements, which highlighted a reduction in the coordination number of W atoms and a corresponding contraction of WO bond lengths. This charge redistribution between Bi and W atoms due to oxygen vacancies leads to localized structural perturbations, as further evidenced by PAS, which showed increased positron lifetimes associated with vacancy clusters, particularly around the Bi and W atoms. These vacancies create defective sites that trap photogenerated electrons, preventing their recombination with holes, thereby significantly enhancing photocatalytic performance. The enhanced photocatalytic activity was demonstrated by the nearly 98 % degradation of Rhodamine B dye under visible-light irradiation, a substantial improvement over the 70 % degradation achieved by the untreated sample. This work presents an innovative approach for generating stable oxygen vacancies in Bi₂WO₆ nanolayers and offers an in-depth understanding of the mechanisms that enhance photocatalytic performance, providing valuable insights for advancing photocatalysts designed for environmental remediation.

Structural Disorder of a Layered Lithium Manganese Oxide Cathode Paving a Reversible Phase Transition Route toward Its Theoretical Capacity.

Layered lithium manganese oxides suffer from irreversible phase transitions induced by Mn migration and/or dissolution associated with the Jahn-Teller effect (JTE) of Mn3+, leading to inevitable capacity fading during cycling. The popular doping strategy of oxidizing Mn3+ to Mn4+ to relieve the JTE cannot completely eliminate the detrimental structural collapse from the cooperative JTE. Therefore, they are considered to be impractical for commercial use as cathode materials. Here, we demonstrate a layered lithium manganese oxide that can be charged and discharged without any serious structural collapse using metastable Li-birnessite with controlled structural disorder. Although Li-birnessite is thermodynamically unstable under ambient conditions, Li ion exchange into Na-birnessite followed by an optimal dehydration resulted in a disordered Li-birnessite. The control over crystal water in the interlayer provides intriguing short-range order therein, which can help to suppress parasitic Mn migration and dissolution, thereby ensuring a reversible electrochemical cycling. The Mn redox behavior and local structure change of the Li-birnessite were investigated by ex situ soft X-ray absorption spectroscopy (sXAS) and X-ray pair distribution function (PDF) analysis. The combined sXAS and PDF with electrochemical analyses disclosed that the reversible Mn redox and suppressed phase transitions in Dh Li-birnessite contribute to dramatically improving its electrochemical reversiblity during cycling. Our findings underscore the substantial effects of controlled static disorder on the structural stability and electrochemical reversibility of a layered lithium manganese oxide, Li-birnessite, which extends the practical capacity of layered oxides close to their theoretical limit.