Strong Band Research Articles

Bis(10-oxacorrole) with Fused Pyridine as a Linker: Synthesis, Structure, and Interaction between the Subunits in the Neutral, Mono- and Dicationic States.

Pyridine-fused bis(oxacorrole)s are obtained by a Hantzsch-type cyclization using arylaldehydes and 3-amino-10-oxacorrole. Spectroscopic characteristics, corroborated by DFT calculations, indicate aromaticity of the dimer and strong interaction between the subunits. Electrochemical and spectroelectrochemical analyses indicate facile access to cation radicals and dicationic species. The oxidized forms are characterized by electronic and electron spin resonance spectroscopies as well as by DFT calculations. Monocations give rise to strong absorption bands in the NIR region between 1500 and 2500 nm, while dications are characterized by a series of absorptions between 1000 and 2200 nm. ESR and VT NMR experiments indicate the presence of singlet-triplet spin equilibria for the solution of the dication. For the dication of bis(oxacorrole) in the singlet ground state, neither aromaticity nor antiaromaticity has been detected by low-temperature 1H NMR and GIAO calculations despite delocalization of π-electrons.

Prevalence Of Achilles Tendinopathy Among Young Basketball Players

Background: Achilles tendinopathy is a common overuse injury affecting the Achilles tendon, the strong band of tissue that connects the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus). This condition is typically characterized by pain, swelling, and limited functionality in the tendon, often occurring in athletes, especially those who engage in activities involving running, jumping, or repetitive stress on the lower legs. Aim: This study investigates prevalence of Achilles tendinopathy and its association with symptoms of population in young male basketball players. Settings & Designs: Cross sectional analytical study. Materials & Methods: This study involved 80 young male basketball players, with a mean age of 18 to 25 years participants from different sports stadiums in Cuddalore district. The royal London test was used to assess the presence of Achilles tendinopathy, while the Victorian institute of sports assessment Achilles questionnaire was used to evaluate the severity of pain in Achilles tendinopathy among the participants. Results: Our finding show that 63 % of the participants had Achilles tendinopathy. Out of 63%, 24% are at mild risk, 56% are at moderate risk and 20% are at severe risk. Height and weight showed no significant association with Achilles tendinopathy. However, the age of the participants showed a significant association with Achilles tendinopathy. Conclusion: prevalence of Achilles tendinopathy is common among young male basketball players. Age being a contributing factor while other physical characteristics had no significant impact.

Pyridine-Fused Bis(azacorrole)s: Easily Accessible NIR III Absorbing Cation Radicals and Biradicaloids of Antiaromatic Ground State.

A family of pyridine-fused bis(porphyrinoids) is obtained, including constitutionally isomeric bis(azacorrole)s, azacorrole-oxacorrole, as well as azacorrole-norcorrole heterodimers by two distinct synthetic approaches. Spectroscopic characteristics, corroborated by Density Functional Theory (DFT) calculations, indicate aromaticity of the bis(azacorrole) as well as azacorrole-oxacorrole products, while for the azacorrole-norcorrole heterodimers, the presence of both dia- and paratropic currents is detected. Electrochemical analyses indicate facile chemical access to cation radicals and dicationic species that have been characterized by electronic and electron spin resonance spectroscopy as well as by DFT calculations. Monocations give rise to the relatively strong absorption bands in the near infra red (NIR) region between 2400 and 3200nm, while dications are characterized by a series of absorptions between 1000 and 2200nm. Electron spin resonance (ESR) experiments indicate the presence of singlet-triplet spin equilibria for the dications. For the dication of bis(azacorrole) of the most planar structure, the singlet ground state is established, and low temperature nuclear magnetic resonance (NMR) as well as gauge-independent atomic orbital NMR calculations indicate its antiaromatic character.

Development of Orange-Emitting Sm2O3-Doped Tellurite Glasses Prepared for Solid State Lighting

A series of glass samples, with base composition of (40-x) TeO2: 30B2O3: 20ZnO: 10Li2O, was modified by incorporating varying concentrations of Sm2O3 (x = 0.00, 0.10, 0.50, 1.00, 1.50, and 2.00 mol%). X-ray diffraction analysis confirmed the amorphous nature of the prepared glasses. FTIR spectroscopy was used to investigate the structural arrangement of the glasses, revealing characteristic vibrational bands associated with Te-O, B-O, and Zn-O bonds. These bands provided insights into the glass network's evolution with changing Sm2O3 content. The optical properties of the glasses were investigated through absorption and photoluminescence studies. Absorption spectra, measured in the 400-1800 nm range, displayed seven peaks attributed to electronic transitions within the Sm3+ ion. These transitions originated from the 6H5/2 ground state to various excited states. Photoluminescence analysis, excited at 403 nm, revealed a strong emission band centered at 597 nm. This emission corresponded to the 4G5/2 → 6H7/2 transition of Sm3+, responsible for the characteristic orange luminescence. The emission intensity increased with increasing Sm2O3 concentration up to 1.00 mol%, after which concentration quenching led to a decrease in intensity. In conclusion, this study elucidates the composition-structure-property relationships in Sm2O3-doped TeO2-B2O3-ZnO-Li2O glasses. The tunable orange emission suggests their potential as phosphors for solid-state lighting applications, particularly in orange LEDs.

Dicyanovinyl Appended Carbazole Based Colorimetric Sensor for Volatile Organic Amines

AbstractHerein we report synthesis, photophysical properties and amine sensing applications of a carbazole‐dicyanovinyl based sensor (2). Sensor molecule 2 shows solid state fluorescence (φ=~41 %), mechanochromic fluorescence and aggregation induced emission. Presence of donor and acceptor groups in 2 resulted in strong absorption bands in the visible region of electromagnetic spectrum which is exploited for colorimetric sensing of primary amines. Amine sensing mechanism of 2 is established using 1H NMR titration studies. Test kit developed using probe 2 showed prominent color change in presence of biogenic amines generated from decomposed meat product.

Synthesis of silver nanoparticles using Azadirachta indica leaf extracts for heavy metal sensing

Silver nanoparticles (AgNPs) was synthesized via cheap bio-reduction and green method from leaf extracts of Azadirachta indica. The technique was optimized by studying variables such as pH, temperature and concentration of the plant extracts. Gas Chromatography Mass Spectroscopy (GC-MS) results indicated the presence of phytonutrients such as Piperidine, 2-Azacyclooctanone, 4-Dibenzofuranamine, Lauric anhydride, Cyclododecanol and Sorbic acid as the phytonutrients responsible for the reduction and resilience process. FT-IR results gave absorption bands indicating the presence of -OH, -NH and -C=O functional groups, while particle size analysis revealed an average particle size which is less than 100 nm, thus confirming the formation of a nanoparticle. UV-Vis investigation of the nanoparticles synthesized with concentration of 12.5 mg/mL produced a strong plasmon resonance band with an absorbance of 0.223 at 400 nm after 24 hrs incubation time and at a minimal concentration of 6.25 mg/mL, the absorbance further decreased with a hypsochromic shift to 600 nm. The synthesized silver nanoparticles showed excellent optical property towards the selected heavy metals with virtual color change and a shift in absorbance towards higher value. Selective detection of Pb2+, Cu2+ and Cd2+ was also confirmed by UV-visible spectra which is well pronounced with Pb2+ having the highest absorbance.

A Study of Emission Lines in Carbon Stars

Abstract Carbon stars are chemically peculiar stars with high carbon abundance, showing strong carbon molecule bands and rare emission lines in their spectra. This paper explores the stellar activity of carbon stars by identifying emission line features in their spectra. An outlier detection method based on morphological feature extraction and interval representation is used to identify 88 targets presenting emission lines from 3546 carbon star spectra. Of these, 55 targets present Balmer series emissions, 35 show forbidden lines ([O i]λ6301 Å, [O iii], [N ii], [S ii], with only 2 of the 35 spectra that present forbidden lines not showing [O i]) and only 2 objects presenting two types of emission lines, and 51 spectra showing Balmer series emissions are C-N stars. This indicates the existence of a continuous stellar wind forming shock waves around the star, suggesting the presence of mass loss or tidal effects and exchange of materials from the companion star. In addition, 23 spectra presenting [O i] emissions are from C-H carbon stars. These are mainly concentrated in a high-Galactic-latitude region with b > 3 0 ∘ , where the influence of halo clusters could lead to relatively strong magnetic activity. Other objects in the Galactic disk may also show stronger magnetic activity due to the influence of a dense medium or magnetic field, rotation, and convection within stars. In addition, one spectrum shows both [O i] and Balmer series emissions, probably caused by magnetic activity and wave shock. Another spectrum shows both Balmer series and [O iii] emissions, presumably contaminated by an unknown nebula.

Extraordinary SERS on nanostructured self-assembled silver films due to preliminary random nano-profiling of substrate and ultrasonic exposure of analyte during the deposition.

Extraordinary SERS on nanostructured self-assembled silver films due to preliminary random nano-profiling of substrate and ultrasonic exposure of analyte during the deposition.

Carrier Dynamics of Facet‐Dependent Heterogeneous Interfaces in High‐Performance Perovskite Solar Cells

AbstractUnderstanding carrier dynamics at interfaces and the interplay of surface structures is critical for improving perovskite solar cells. However, the competitive impact of facet‐dependent terminations and defects on carrier behavior remains unclear. Herein, carrier dynamics at all interfaces of quasi‐single‐crystal films with (001) and (111) preferred orientation are investigated. The carrier extraction time of the (001) top interface is the shortest (0.57 ns), followed by that of the (111) top interface (1.32 ns), while the (001)/(111) buried interfaces take longer times (3.61 and 5.87 ns), respectively. Carrier extraction at the top interface is observed to be markedly more efficient than that at the buried interface, attributed to the strong interfacial dipole and favorable band alignment induced by heterostructures involving phosphate group interactions. Moreover, the carrier extraction at the top interface of the (111) film is much lower than that of the (001) film due to severe defect‐assisted nonradiative recombination. It reveals that exposed surface terminations can influence the formation energy of interfacial defects, leading to the deep‐level defects. Ultimately, the (001)‐oriented device with excellent carrier extraction obtains a champion power conversion efficiency of 25.26% and a T90 lifetime of 400 h during maximum power point tracking.

Cellulose acetate from fast-growing hardwood – Trema orientalis: investigating acetylation parameters and viscosity

In this study, dissolving pulp from hardwood, Trema orientalis L. was used as cellulose pulp for the synthesis of cellulose acetate (CA). CA was prepared by varying time of swelling with acetic acid, duration of reaction and temperature of reaction. The degree of substitution (DS) of all prepared CA was higher than 2.5, indicating the formation of cellulose triacetate (CTA). The maximum yield of CTA was 157 wt-% after 3 hours of cellulose pulp swelling followed by a 1.5-hour acetylation reaction at 35 °C. The all prepared CA samples showed good solubility in dimethyl sulphoxide (DMSO), N,N-dimethyl formamide (DMF) and tetrahydrofuran (THF). The creation of strong absorption band at 1740 cm−1 for carbonyl (–C=O) group confirms successful acetylation reaction. The cellulose crystallinity diminishes as the acetylation progresses as observed by X-ray diffraction (XRD). The prepared CA samples were also characterised using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic viscosity measurements. The CA/DMSO solutions exhibited shear thinning property at lower shear rate and higher operating temperature. Increased dynamic viscosity was observed with the increase in concentration of CA in the DSMO solvent. The crystallinity and thermal stability of CA samples was highly influenced by the duration of acetylation and temperature of reaction.

ИСПОЛЬЗОВАНИЕ ИК- И ЭЛЕКТРОННОЙ СПЕКТРОСКОПИИ ДЛЯ АНАЛИЗА АКТИВАТОРА ПЕСТИЦИДОВ И АГРОХИМИКАТОВ

The purpose of the study is to evaluate the capabilities of IR and electron spectroscopy methods for analyzing the organosilicon activator of pesticides and agrochemicals based on polyalkylene oxide siloxane and determining its residual quantities on grape bunches during the harvest season. The objects of research are Aligote and Cabernet Sauvignon grape varieties, the organosilicon adjuvant Atomic and its model mixtures with distilled water, as well as grape rinsing water. The analysis was carried out using electron spectroscopy and Fourier transform infrared spectroscopy using an attenuated total internal reflection (ATR) attachment with a diamond element. It has been shown that in the Atomic IR spectrum there is a very strong characteristic absorption band of stretching vibrations of the Si–O and C–O bonds at 1077 cm-1, which may be a marker of the presence of this adjuvant in its mixtures with water. A wide absorption band for stretching vibrations of O–H bonds was also found at 3389 cm-1. The absorption band of stretching vibrations of the Si–O and C–O bonds of the Atomic adjuvant is observed in the IR spectra of its mixtures with water up to a ratio of 1:69 (by volume). In the Atomic electronic spectrum, absorption maxima were found at 276 and 310 nm. The absorption maximum at ≈270 nm remains with further dilution, but is practically no longer visible in the spectrum of the Atomic mixture with water in a ratio of 1:500 (by volume). Under experimental conditions, IR and electron spectroscopy methods did not reveal any residual amounts of the Atomic adjuvant in the rinsing water from Aligote and Cabernet Sauvignon grape varieties pre-treated with it. The results obtained can be used in the analysis of the Atomic activator and other products based on polyalkylene oxide siloxane in various mixtures used in agriculture for treating plants.

Phase‐Field Simulation of Carbon Diffusion during Banded Structure Formation in Low‐Carbon Steel

During the cooling process after rolling, low‐carbon steel frequently develops banded structures, primarily due to the segregation of alloying elements and the uneven diffusion of carbon under a slow cooling rate during phase transformation. The current work integrates experiment and simulation to discuss the influence of various cooling rates on ferrite and pearlite bands in Cr–Mn–Ti low‐carbon steel. Meanwhile, a multicomponent multiphase‐field model is established to quantitatively analyze carbon diffusion behavior during the evolution of austenite–ferrite. The results reveal that low cooling rates and the segregation of Mn, Si, and Cr elements can promote the formation of banded structure. Furthermore, in the solute‐poor regions, slow cooling rates allow sufficient time for carbon diffusion during austenite–ferrite transformation, which leads to the extension in both carbon diffusion distance and interface migration distance, thereby generating severe ferrite bands. Additionally, in the solute‐rich regions, as the cooling rate decreases, C concentrations at Ar3 temperature and Ar1 temperature increase, inhibiting the nucleation and growth of ferrite, thereby resulting in strong pearlite bands. This study further elucidates the formation mechanisms of ferrite and pearlite bands, enhancing the understanding of carbon diffusion behavior during banded structure formation.

Rotation symmetry mismatch and interlayer hybridization in MoS2-black phosphorus van der Waals heterostructures

Interlayer coupling in 2D heterostructures can result in a reduction of the rotation symmetry and the generation of quantum phenomena. Although these effects have been demonstrated in transition metal dichalcogenides (TMDs) with mismatched interfaces, the role of band hybridization remains unclear. In addition, the creation of flat bands at the valence band maximum (VBM) of TMDs is still an open challenge. In this work, we investigate the electronic structure of monolayer MoS2-black phosphorus heterojunctions with a combined experimental and theoretical approach. The disruption of the rotational symmetry of the MoS2 bands, the creation of anisotropic minigaps and the appearance of flat bands at the Γ valley, accompanied by the switch of VBM from K to Γ, are clearly observed with micro-ARPES. Unfolded band structures obtained from first principles simulations precisely describe these multiple effects – all independent of the twist angle – and demonstrates that they arise from strong band hybridization between Mo dz2 and P px orbitals. The underlying physics revealed by our results paves the way for innovative electronics and optoelectronics based on TMDs superlattices, adding further flexibility to the approaches adopted in twisted hexagonal superlattices.

PHANGS-ML: The Universal Relation between PAH Band and Optical Line Ratios across Nearby Star-forming Galaxies

Abstract The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on the local radiation field, gas composition, and dust grain properties. Of particular importance are polycyclic aromatic hydrocarbons (PAHs), which emit strong vibrational bands in the mid-infrared, and play a key role in the ISM energy balance. We recently identified global correlations between PAH band and optical line ratios across three nearby galaxies, suggesting a connection between PAH heating and gas ionization throughout the ISM. In this work, we perform a census of the PAH heating–gas ionization connection using ∼700,000 independent pixels that probe scales of 40–150 pc in 19 nearby star-forming galaxies from the PHANGS survey. We find a universal relation between log PAH(11.3 μm/7.7 μm) and log ([S ii]/Hα) with a slope of ∼0.2 and a scatter of ∼0.025 dex. The only exception is a group of anomalous pixels that show unusually high (11.3 μm/7.7 μm) PAH ratios in regions with old stellar populations and high starlight-to-dust emission ratios. Their mid-infrared spectra resemble those of elliptical galaxies. Active galactic nucleus hosts show modestly steeper slopes, with a ∼​​​​​​10% increase in PAH(11.3 μm/7.7 μm) in the diffuse gas on kiloparsec scales. This universal relation implies an emerging simplicity in the complex ISM, with a sequence that is driven by a single varying property: the spectral shape of the interstellar radiation field. This suggests that other properties, such as gas-phase abundances, gas ionization parameter, and grain charge distribution, are relatively uniform in all but specific cases.

Yellow fluorescent UV-curable epoxy acrylate/VTMS-modified GQDs coatings: study of UV-blocking and viscoelastic properties

Polymer coatings decompose in the presence of UV radiation from sunlight and beget economic and environmental losses. Hence, it is necessary to reinforce the polymer coatings with UV-blocking nanoparticles and to convert the UV light into visible light. In this research work, the surface of graphene quantum dots (GQDs) was modified by vinyltrimethoxysilane (VTMS). VTMS-modified GQDs (VmGQDs) including 0, 0.3 and 0.6 wt% were taken into account to synthesize UV-curable epoxy acrylate/VmGQDs (Ep/VmGQDs) nanocomposite coatings. Surface modification, UV-blockage, fluorescence features and viscoelastic properties of Ep/VmGQDs coatings were analyzed by various spectrometry tests. The existence of VmGQDs (0.3 wt% and 0.6 wt%) in the polymer matrix led to absorption of UV rays in UV regions and fluorescence emission in the visible area with 578 nm wavelength (yellow fluorescence). Appearance of strong absorption bands at 250, 285 and 365 nm by the coatings with VmGQDs confirmed that a large portion of UV rays was absorbed and blocked. The intensity of UV-blockage by Ep/VmGQDs 0.6 wt% was recorded >99%. Furthermore, reinforcement of the coatings with VmGQDs resulted in increase in storage modulus, cross-linking density and Tg value.

Commercial immunoassays in paraneoplastic neurological syndromes: an Australian laboratory perspective.

Paraneoplastic antibodies are implicated in heterogeneous clinical presentations. Commercial immunoassays include indirect immunofluorescence (IIF), and line immunoblot (LIB). LIB can be associated with false positives, and unfortunately, further confirmatory assays are not readily available in diagnostic laboratories. To determine frequency of positive LIB on serum or cerebrospinal fluid (CSF) using EUROLine paraneoplastic neurological syndromes (PNS) 12 Ag Test kit (EuroImmun, Germany) and establish concordance with IIF on Nova Lite kit (Inova Diagnostics, United States) and clinical presentation. A retrospective analysis of all LIB performed over a four-year period was undertaken. Healthy control samples were also analysed with IIF and LIB. Two thousand and eighty-one LIB samples were processed, 91 (4.4%) were positive from 69 patients with a median age of 64 years. There were 37 females (53.6%). Some samples had two antibody specificities (n = 6, 6.6%). Of those with one antibody, GAD65 (n = 22), Yo (n = 19), SOX1 (n = 17) and amphiphysin (n = 14) were most frequent. Of the positive LIBs, 80 (87.9%) had concurrent IIF and eight samples (10%) had a typical IIF pattern. Clinical relevance of a positive LIB, irrespective of IIF, was seen in 15/91 samples (14.3%) from nine patients; GAD65 (n = 3), Hu (n = 2), amphiphysin (n = 1), Yo (n = 1), Tr (n = 1) and CV2 (n = 1). Of the 71 healthy controls, five (7.0%) had a positive LIB: medium band (n = 4, 5.6%: amphiphysin, CV2, SOX1 and Yo) and strong band (n = 1, 1.4%: Yo). All IIF were negative. On average, signal intensity (SI) was higher in those with disease (SI 77.3/very strong band) compared to those without (SI 28.6/strong band) and healthy controls (SI 2/negative band) (p < 0.0001). LIB has a high false positive rate, and in this cohort, there were more false than true positive results. The assay must be used in those with a high clinical suspicion for PNS. While the commercial IIF kit is a useful test, it is insufficient to be used as a screening strategy in isolation.

Removal of Indigo Carmine Dye Using NiO Nanoparticles Extracted from Citrus Limon Leaf Extract.

In the current study a green approach was carried out to prepare nickel oxide nanoparticles (NiO-NPs) using Citrus limon leaf extract and nickel nitrate hexahydrate Ni(NO3)2.6H2O as a precursor. The synthesized NiO-NPs were characterized using the Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD). The FTIR spectrum showed a strong broad band at 422 cm-1 corresponding to Ni–O stretching vibration of the NiO nanocrystals. The XRD pattern revealed that NiO-NPs possess a cubic crystalline structure with an average crystallite size of 14.5 nm. The NiO-NPs were employed as an adsorbent for the removal of Indigo Carmine (IC) dye from aqueous solutions under different functional parameters, including adsorbent weight, adsorption duration, temperature, pH value, and initial IC dye concentration. The adsorption processes were monitored using UV-vis. spectrophotometry. The results obtained showed that the Langmuir model of adsorption isotherm analysis fits the equilibrium experimental data more accurately than the Freundlich model, and the pseudosecond order (PSO) kinetic model was more appropriate than the pseudo-first order (PFO) kinetic model. The thermodynamic estimation of the adsorption of IC onto NiO-NPs revealed a spontaneous exothermic process with an increase in randomness, with negative Gibbs free energy (Go ) and enthalpy (Ho ) values and a positive entropy (So ) value.

Sonochemical synthesis of CQDs from coffee husk: Insights in aggregation mechanism, optimization and sustainability analysis.

Sonochemical synthesis of CQDs from coffee husk: Insights in aggregation mechanism, optimization and sustainability analysis.

Role of outer membrane vesicles of hypervirulent Klebsiella pneumoniae isolated from bovine uterine discharge in pro-inflammatory dysregulation

Numerous research studies have established a connection between hypervirulent Klebsiella pneumoniae (hvKP) and bovine abortion, as well as other complications and clinical illnesses. These bacteria, which belong to the Gram-negative group, release outer membrane vesicles (OMVs), believed to play a crucial role in transporting effector molecules to their target cells. To investigate this further, OMVs of hvKP were collected from 47 clinical isolates from bovine uterine discharge samples using ultracentrifugation. Confirmation of the 47 isolates was carried out through a standard PCR test targeting the 16S rRNA gene. Subsequently, a multiplex PCR was used to verify positive 16S rRNA gene results by detecting specific virulence genes (fimH, acrAB, traT, and rmpA). The standard PCR test showed that 27 out of the 47 isolates (57.45%) tested positive for the 16S rRNA gene, with all 27 of these isolates also testing positive for the rmpA and traT genes. Additionally, 30% of the isolates (8.1 out of 27) tested positive for AcrAB, while 70% of the isolates (18.9 out of 27) tested positive for FimH. During SDS-Western blotting, ten protein bands with molecular weights ranging from 18 to &gt;60 kDa were identified in K. pneumoniae-derived OMV preparations. These bands included OmpX, flagellin, MipA, OmpA, OmpC, and OmpF (42-44 kDa), a strong OmpA band at 45 KDa, and a faint band at 60 kDa of GroEL as an oligomer of OmpA. Furthermore, hvKP OMVs displayed varying cytotoxic effects on the L929 and THP-1 cell lines. Notably, incubating THP-1 cells with high concentrations of hvKP OMVs inhibited IL-1β and TNF responses, indicating that these OMVs may not only facilitate the internalisation of the bacterium by THP-1 cells but also suppress the cells’ innate immune response to hvKP infection. This ability of hvKP OMVs to evade the immune system and modulate host responses contributes significantly to the bacterium’s pathogenicity.

D-band state control engineering over ZnIn2S4 for enhanced photoreduction of CO2 to CH4.

D-band state control engineering over ZnIn2S4 for enhanced photoreduction of CO2 to CH4.