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Analytical Sciences : the International... Jun 2024Organotin compounds (OTC), mainly tributyltin (TBT), have been used since the 1970s as biocides in the composition of antifouling paints. Due to its physical-chemical...
Organotin compounds (OTC), mainly tributyltin (TBT), have been used since the 1970s as biocides in the composition of antifouling paints. Due to its physical-chemical characteristics, TBT has high toxicity to the marine environment affecting non-target organisms. The present study aims to develop a method of direct visual identification of TBT in antifouling paints using the cyclopalladate complex, 4- (2-thiazolylazo) resorcinol (TAR-Pd), synthesized in our laboratory. Tests were performed in blank and in the paint matrix with the following OTC: TBT-O; TBT-Cl; TPT-Cl; DBT-Cl (tributyltin oxide, tributyltin chloride, triphenyltin chloride, dibutyltin chloride), in addition to the SnCl and SnCl compounds (tin IV chloride and tin II chloride), all at a concentration of approximately 20 g/ kg of dry paint). The test was performed by applying paint samples to test bodies and scraping a few tens of milligrams of the dry paint film. The scraped paint samples were submitted to the test, showing a different staining reaction for the TBT-Cl and SnCl samples concerning blank and other samples (TBT-O, TPT, DBT-Cl, and SnCl). Solution tests were performed to characterize reaction products by spectroscopy in the visible band. The method developed has potential for application in real samples, being selective for TBT-Cl and SnCl in an acid medium, obtaining a limit of detection, in the range of 1-10 mg/kg dry paint.
PubMed: 38907795
DOI: 10.1007/s44211-024-00620-9 -
Spectrochimica Acta. Part A, Molecular... Jun 2024A stable and efficient hole-transport material (HTM) is crucial for high-performance perovskite solar cells (PSCs). A...
A stable and efficient hole-transport material (HTM) is crucial for high-performance perovskite solar cells (PSCs). A 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-MeOTAD) being used widely to prepare highly efficient PSCs. However, Spiro-MeOTAD has some limitations due to its complex synthesis, which increases its cost, and it also requires dopants to improve its performance. Therefore, we designed thirteen unique small-molecule-based HTMs (MK1-MK13), which are easy to synthesize, highly cost-effective, and don't require dopants to prepare efficient PSCs. Their electrical and optical properties are then investigated theoretically using advanced quantum chemical approaches. The designed molecules showed lower energy gaps and improved optical and optoelectronic characteristics because of the improved phase inversion geometry. The detailed photo-physical and optoelectronic characteristics have been studied using density functional theory (DFT) and time-dependent (TD-DFT) calculations. Moreover, we investigated the impact of holes and electrons and the density of states, open-circuit voltage, frontier molecular orbital, transition density matrix, and other structural and photovoltaic characteristics of these materials. Among these, the MK3 molecule possesses the much narrower optical band gap of 1.04 eV and absorbance (λ ) of 684 nm, respectively. In addition, a profound investigation of the MK3/PCBM blend shows excellent charge transfer at the acceptor-donor interface. Therefore, our proposed technique is necessary for generating appropriate photovoltaic materials for efficient optoelectronic devices and is helpful in further advancing the field.
PubMed: 38906061
DOI: 10.1016/j.saa.2024.124615 -
Noise & HealthDigital noise reduction (DNR) minimizes the effect of noise on speech signals by continuously monitoring frequency bands in the presence of noise. In the present study,...
AIMS
Digital noise reduction (DNR) minimizes the effect of noise on speech signals by continuously monitoring frequency bands in the presence of noise. In the present study, we explored the effect of DNR technology on speech intelligibility in individuals using hearing aids (HAs) and investigated implications for daily use.
METHODS AND MATERIAL
Eighteen participants with bilateral moderate sensorineural hearing loss (aged 16-45 years) were included. Bilateral receiver-in-the-ear HAs were fitted in the participants. The adaptive and nonadaptive (with a signal-to-noise ratio (SNR) of +5 and -5 dB, respectively) Turkish matrix sentence test (TURMatrix) in noise and free-field hearing assessments, including hearing thresholds with hearing aids, speech recognition thresholds (SRT), and speech discrimination scores, were conducted in two different conditions: HA in the DNR-on and DNR-off conditions.
RESULTS
No significant difference was observed between free-field hearing assessments with the HA in the DNR-off and DNR-on conditions (P > 0.05). Furthermore, the adaptive and nonadaptive TURMatrix revealed significant differences between the scores under the DNR-on and DNR-off conditions (P < 0.05). Nevertheless, under the DNR-on condition, there was no correlation between free-field hearing assessments with HA and TURMatrix results (P > 0.05). However, a significant correlation was observed between SRT scores with HA and TURMatrix scores (adaptive and nonadaptive, +5 and -5 dB SNR, respectively) under the DNR-off condition (P < 0.05).
CONCLUSION
Our study findings suggest that DNR can improve speech intelligibility in noisy environments. Therefore, DNR can enhance an individual's auditory comfort by improving their capacity to grasp speech in background noise.
Topics: Humans; Hearing Aids; Adult; Noise; Male; Middle Aged; Hearing Loss, Sensorineural; Female; Young Adult; Adolescent; Speech Intelligibility; Signal-To-Noise Ratio; Auditory Threshold; Speech Perception; Speech Reception Threshold Test
PubMed: 38904826
DOI: 10.4103/nah.nah_67_23 -
Journal of Environmental Management Jun 2024Anaerobic oxidation of methane (AOM) is a microbial process of importance in the global carbon cycle. AOM is predominantly mediated by anaerobic methanotrophic archaea...
Anaerobic oxidation of methane (AOM) is a microbial process of importance in the global carbon cycle. AOM is predominantly mediated by anaerobic methanotrophic archaea (ANME), the physiology of which is still poorly understood. Here we present a new addition to the current physiological understanding of ANME by examining, for the first time, the biochemical and redox-active properties of the extracellular polymeric substances (EPS) of an ANME enrichment culture. Using a 'Candidatus Methanoperedens nitroreducens'-dominated methanotrophic consortium as the representative, we found it can produce an EPS matrix featuring a high protein-to-polysaccharide ratio of ∼8. Characterization of EPS using FTIR revealed the dominance of protein-associated amide I and amide II bands in the EPS. XPS characterization revealed the functional group of C-(O/N) from proteins accounted for 63.7% of total carbon. Heme-reactive staining and spectroscopic characterization confirmed the distribution of c-type cytochromes in this protein-dominated EPS, which potentially enabled its electroactive characteristic. Redox-active c-type cytochromes in EPS mediated the EET of 'Ca. M. nitroreducens' for the reduction of Ag to metallic Ag, which was confirmed by both ex-situ experiments with extracted soluble EPS and in-situ experiments with pristine EPS matrix surrounding cells. The formation of nanoparticles in the EPS matrix during in-situ extracellular Ag reduction resulted in a relatively lower intracellular Ag distribution fraction, beneficial for alleviating the Ag toxicity to cells. The results of this study provide the first biochemical information on EPS of anaerobic methanotrophic consortia and a new insight into its physiological role in AOM process.
PubMed: 38901321
DOI: 10.1016/j.jenvman.2024.121523 -
Ultrasonics Jun 2024Features of an application of a High-overtone Bulk Acoustic Resonator (HBAR) as a high-pressure sensor have been considered. In this way, the second version of an...
Features of an application of a High-overtone Bulk Acoustic Resonator (HBAR) as a high-pressure sensor have been considered. In this way, the second version of an integrated measurement system combining a Diamond Anvil Cell (DAC) and an HBAR operating in the microwave frequency band from 1.3 to 3.7 GHz was developed. A specific configuration of HBAR based on a piezoelectric layered structure as "Al/ASN/Mo/(100) diamond" was proposed. Two independent methods of pressure control were used to calibrate the embedded HBAR as a pressure sensor: a stress-induced shift of the diamond Raman line and the shift of the R1 luminescence line of Cr in the ruby matrix. A stable correlation between the frequency shifts of the acoustic overtones in the HBAR, the shift of the diamond Raman line and the shift of the R1 line with a change in pressure applied to the W-gasket with embedded ruby particles was established in the range of 0 … 30 GPa. The sensitivity of an investigated sensor to the pressure variation was found to be equal 1ΔPΔff=4.8∙10GPa. The maximal value of 30 GPa obtained in a given work can be easily increased after a minor reconfiguration of the DAC. Considering the range of 0 - 5 GPa a proposed built-in DAC acoustoelectronic sensor has the better performance and sensitivity compared with known methods of a pressure measurement.
PubMed: 38897038
DOI: 10.1016/j.ultras.2024.107380 -
Materials (Basel, Switzerland) May 2024It is generally known that the incorporation of crystals in the glass matrix can enhance the ductility of metallic glasses (MGs), at the expense of reduced strength, and...
It is generally known that the incorporation of crystals in the glass matrix can enhance the ductility of metallic glasses (MGs), at the expense of reduced strength, and that the deformation of MGs, particularly during shear banding, can induce crystal formation/growth. Here, we show that these known trends for the interplay between crystals and deformation of MGs may hold true or become depending on the size of the crystals relative to the shear bands. We performed molecular dynamics simulations of tensile tests on nanocrystal-bearing MGs. When the crystals are relatively small, they bolster the strength rather than the ductility of MGs, and the crystals within a shear band undergo redissolution as the shear band propagates. In contrast, larger crystals tend to enhance ductility at the cost of strength, and the crystal volume fraction increases during deformation. These insights offer a more comprehensive understanding of the intricate relationship between deformation and crystals/crystallization in MGs, useful for fine-tuning the structure and mechanical properties of both MGs and MG-crystal composites.
PubMed: 38893831
DOI: 10.3390/ma17112567 -
Molecules (Basel, Switzerland) Jun 20244,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based molecules have emerged as interesting materials for optoelectronic applications due to the possibility to...
4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based molecules have emerged as interesting materials for optoelectronic applications due to the possibility to easily fine-tune their photophysical and optical properties, dominated by two main absorption bands in the visible range. However, no studies have been reported on the nature of these spectral features. By means of ultrafast spectroscopy, we detect intramolecular energy transfer in a spin-coated film of di-thieno-phenyl BODIPY (DTPBDP) dispersed in a polystyrene matrix after pumping the high-energy absorption band. The same effect is not present upon pumping the lowest-energy band, which instead allows the achievement of efficient amplified spontaneous emission. Density functional calculations indicate the different nature of the two main absorption bands, explaining their different photophysical behavior.
PubMed: 38893501
DOI: 10.3390/molecules29112625 -
International Journal of Biological... Jun 2024Multifunctional transparent woods have recently attracted a great interest as efficient products for many applications, such as smart window and smart packaging. Herein,...
Multifunctional transparent woods have recently attracted a great interest as efficient products for many applications, such as smart window and smart packaging. Herein, a transparent wood with several desirable properties, including flame-retardant activity, ultraviolet shielding, superhydrophobicity, good roughness, durability and photostability was developed. The current photoluminescent wood showed a remarkable capacity to keep releasing light in the dark for extended durations. Multifunctional transparent wood was prepared by infiltrating a delignified wooden bulk with a combination of polyvinyl alcohol (PVA), ammonium polyphosphate (APP), cellulose nanocrystals, and rare-earth strontium aluminate nanoparticles (RSAN). Cellulose nanocrystals were prepared from microcrystalline cellulose, and used as reinforcement nanofiller to enhance the mechanical strength of the polyvinyl alcohol matrix and a dispersant agent to avoid agglomeration of RSAN. RSAN displayed diameters of 8-16 nm, while cellulose nanocrystals displayed lengths of 75-150 nm and diameters of 5-10 nm. According to photoluminescence spectra and the colorimetric space coordinates reported by the CIE Lab parameters, the transparent wood changed color to bright green when exposed to UV irradiation. For the produced phosphorescent wood surfaces, an absorption band was detected at 365 nm to generate an emission band at 519 nm.
PubMed: 38889827
DOI: 10.1016/j.ijbiomac.2024.133226 -
Journal of Psychiatric Research Jun 2024Suicide in youth and young adults is a serious public health problem. However, the biological mechanisms of suicidal ideation (SI) remain poorly understood. The primary...
Suicide in youth and young adults is a serious public health problem. However, the biological mechanisms of suicidal ideation (SI) remain poorly understood. The primary goal of these analyses was to identify the connectome profile of suicidal ideation using resting state electroencephalography (EEG). We evaluated the neurocircuitry of SI in a sample of youths and young adults (aged 10-26 years, n = 111) with current or past diagnoses of either a depressive disorder or bipolar disorder who were enrolled in the Texas Resilience Against Depression Study (T-RAD). Neurocircuitry was analyzed using orthogonalized power envelope connectivity computed from resting state EEG. Suicidal ideation was assessed with the 3-item Suicidal Thoughts factor of the Concise Health Risk Tracking self-report scale. The statistical pipeline involved dimension reduction using principal component analysis, and the association of neuroimaging data with SI using regularized canonical correlation analysis. From the original 111 participants and the correlation matrix of 4950 EEG connectivity pairs in each band (alpha, beta, theta), dimension reduction generated 1305 EEG connectivity pairs in the theta band, 2337 EEG pairs in the alpha band, and 914 EEG connectivity pairs in the beta band. Overall, SI was consistently involved with dysfunction of the default mode network (DMN). This report provides preliminary evidence of DMN dysfunction associated with active suicidal ideation in adolescents. Using EEG using power envelopes to compute connectivity moves us closer to using neurocircuit dysfunction in the clinical setting to identify suicidal ideation.
PubMed: 38889554
DOI: 10.1016/j.jpsychires.2024.06.016 -
Physical Chemistry Chemical Physics :... Jun 2024The investigation of new properties in two-dimensional (2D) multiferroic heterostructures is significant. In this work, the electronic properties and magnetic anisotropy...
The investigation of new properties in two-dimensional (2D) multiferroic heterostructures is significant. In this work, the electronic properties and magnetic anisotropy energies (MAEs) of 2D multiferroic RuClF/AgBiPS van der Waals (vdW) heterostructures are systematically studied by first principles calculations based on density functional theory (DFT). The Hubbard on-site Coulomb parameter () of Ru atoms is necessary to account for the strong correlation among the three-dimensional electrons of Ru. RuClF/AgBiPS heterostructures in different polarizations (RuClF/AgBiPS-P↑ and RuClF/AgBiPS-P↓) are ferromagnetic semiconductors with stable structures. Valley polarizations are present in the band structures of RuClF/AgBiPS heterostructures with spin-orbit coupling (SOC), the valley splitting energies of which are 279 meV and 263 meV, respectively. The MAEs of RuClF/AgBiPS heterostructures indicate perpendicular magnetic anisotropy (PMA), which are primarily attributed to the differences in matrix elements within Ru (d, d) orbitals. In addition, valley splittings and MAEs of RuClF/AgBiPS heterostructures are modified at different biaxial strains. Specifically, the highest valley splittings are 283 meV and 287 meV at = 2%, while they disappear at = -6%. The PMA of RuClF/AgBiPS-P↑ is gradually decreased at biaxial strains of -6% to 2%, and MAE is transformed into in-plane magnetic anisotropy (IMA) at = 4%. RuClF/AgBiPS-P↓ maintains PMA at different strains. The study of non-volatile electrical control of valley splitting phenomena in multiferroic RuClF/AgBiPS heterostructures is crucial in the field of valleytronic devices, which has important theoretical significance.
PubMed: 38887794
DOI: 10.1039/d4cp01059k