Analysis of Transient Thermoacoustic Characteristics and Performance in Carbon Nanotube Sponge Underwater Transducers.

Recent advancements in marine technology have highlighted the urgent need for enhanced underwater acoustic applications, from sonar detection to communication and noise cancellation, driving the pursuit of innovative transducer technologies. In this paper, a new underwater thermoacoustic (TA) transducer made from carbon nanotube (CNT) sponge is designed to achieve wide bandwidth, high energy conversion efficiency, simple structure, good transient response, and stable sound response, utilizing the TA effect through electro-thermal modulation. The transducer has potential application in underwater acoustic communication. An electro-thermal-acoustic coupled simulation for the open model, sandwich model, and encapsulated model is presented to analyze the transient behaviors of CNT sponge TA transducers in liquid environments. The effects of key design parameters on the acoustic performances of both systems are revealed. The results demonstrate that a short pulse excitation with a low duty cycle could greatly improve the heat dissipation of the encapsulated transducer, especially when the thermoacoustic response time becomes comparable to thermal relaxation time.

Gas Graph Convolutional Transformer for Robust Generalization in Adaptive Gas Mixture Concentration Estimation.

Gas concentration estimation has a tremendous research significance in various fields. However, existing methods for estimating the concentration of mixed gases generally depend on specific data-preprocessing methods and suffer from poor generalizability to diverse types of gases. This paper proposes a graph neural network-based gas graph convolutional transformer model (GGCT) incorporating the information propagation properties and the physical characteristics of temporal sensor data. GGCT accurately predicts mixed gas concentrations and enhances its generalizability by analyzing the concentration tokens. The experimental results highlight the GGCT's robust performance, achieving exceptional levels of accuracy across most tested gas components, underscoring its strong potential for practical applications in mixed gas analysis.

Integrative pharmacology reveals the mechanisms of Erzhi pills, A traditional Chinese formulation, stimulating melanogenesis.

ETHNOPHARMACOLOGICAL RELEVANCE: Erzhi pills (EZP), a traditional Chinese medicine formula prescribed for the treatment of vitiligo, has shown promising efficacy. However, the oral bioactive components and mechanisms underlying the promotion of melanogenesis by EZP remain unclear. AIM OF THE STUDY: This study aimed to investigate the pharmacological basis and mechanism of EZP in promoting melanogenesis. MATERIALS AND METHODS: UHPLC-TOF-MS analysis was used to identify absorbed phytochemicals in serum after oral administration of EZP. Network pharmacology methods were used to predict potential targets and pathways involved in the melanogenic activity of EZP, resulting in the construction of a "compound-target-pathway" network. Zebrafish and B16F10 cells were used to evaluate the effects of EZP on tyrosinase activity and melanin content. Western blot and ELISA analyses were used to validate the effects of EZP on melanogenesis-related proteins, including MITF, TYR, CREB, p-CREB, and cAMP. RESULTS: UHPLC-TOF-MS analysis identified 36 compounds derived from EZP in serum samples. Network pharmacology predictions revealed 89 target proteins associated with the identified compounds and closely related to vitiligo. GO and KEGG analyses indicated the involvement of the cAMP/PKA signaling pathway in the promotion of melanogenesis by EZP. Experimental results showed that EZP increased tyrosinase activity and melanin content in zebrafish and B16F10 cells without inducing toxicity. Western blot and ELISA results suggested that the melanogenic effect of EZP may be related to the activation of the cAMP/PKA signaling pathway. These results confirm the feasibility of combining serum pharmacological and network pharmacological approaches. CONCLUSIONS: EZP have the potential to increase tyrosinase activity and melanin content in zebrafish and cells possibly through activation of the cAMP/PKA pathway.

Comparison of wideband acoustic immittance in Chinese infants under three months of age with normal and abnormal middle ear function.

OBJECTIVES: This study aims to compare the characteristics of Wideband Acoustic Immittance (WAI) in Chinese infants under three months of age, with either normal or abnormal middle ear function. METHODS: We recruited 98 infants with either normal or abnormal middle ear function, and subsequently divided them into four groups based on their middle ear function and chronological age. The absorbances at tympanometric peak pressure (TPP) were collected across 1/3rd octave frequencies ranging from 226 to 8000 Hz. RESULTS: Among infants with normal middle ear function, no significant differences were observed concerning ear laterality. However, significant differences were noted at 3364 Hz and 4000 Hz with respect to age. For infants with either normal or abnormal middle ear function, we found significant differences at the majority of frequencies. Additionally, the receiver operating characteristic (ROC) curves and maxima Youden index indicated that absorbances at 1682 Hz and 1297 Hz could be employed to evaluate the middle ear function of infants at 1 and 2 months of age. CONCLUSION: This study demonstrates that WAI holds promise as a valuable tool for assessing the middle ear condition of infants at 1 and 2 months of age. Infants aged 1 and 2 years, having absorbance values equal to or greater than 0.7470 at 1682 Hz and 0.6775 at 1297 Hz respectively, may indicate normal middle ear function. Furthermore, it underscores the necessity of establishing ethnicity- and age-specific norms for WAI in infants under 3 months of age.

[A preliminary study on wideband acoustic immittance of infants with normal bilateral middle ear function at the age of 1-5 months].

Objective:To explore preliminary characteristics of wideband acoustic immittance of 1- to 5-month-old infants who have bilateral normal middle ear function, so as to contribute to the clinical application of WAI test in the evaluation of middle ear function in infants. Methods:1- to 5-month-old infants were included. After the normal function of bilateral middle ear was determined by otoacoustic emission and high frequency acoustic immittance test, WAI test was performed and the relevant data were collected and analyzed. Results:There was no statistical difference in absorbance at the same frequency between the left ear and right ear of each group（P>0.05）. Absorbance of 4000 Hz increased at first and then decreased with the growth of physiological age, and the sound energy absorption rate of other frequencies decreased except 2670 Hz and 3364 Hz. Conclusion:The outcome of this study shows that it is necessary to establish the national normal value of WAI in 1- to 5-month-old infants who have bilateral normal middle ear function. The purpose of the development of middle ear system is to ensure that sounds in the speech frequency range can be transmitted and heard more effectively.

[Diagnostic value of IT-MAIS scores by logistic regression and ROC curve in predicting the degree of hearing loss in infants and toddlers aged 0-36 months].

Objective:This study is inorder to compare the early prelingual auditory development trajectory of infants and toddlers with normal hearing and different degrees of hearing loss, and to explore the value of the Infant-Toddler Meaningful Auditory Integration Scale （IT-MAIS） scores in the diagnosis of hearing loss severity in infants and toddlers aged 0-36 months. Methods:Eight hundred and forty-two cases of infant-toddler from March 2009 to March 2021 were selected as participants, including 231 cases with normal hearing and 611 cases with hearing loss. The IT-MAIS scores of participants with different degrees of hearing loss were fitted with nonlinear regression with age. By respectively constructing three logistic regression models of IT-MAIS total scores, perception scores, discrimination scores and evaluation age, the ROC curve was drawn to evaluate the diagnostic efficacy. Results:The IT-MAIS scores of children with mild, moderate, severe, and profound hearing loss participants changes with age are similar to the development of infants with normal hearing, and they all increase with age. And the more severe the hearing loss, the slower the growth rate, and the lower the peak value that can be reached. The logistic model constructed by combining IT-MAIS total score and evaluation age is the best to distinguish mild and above, moderate and above, severe and above, and profound hearing loss, whose AUC are 0.827, 0.889, 0.948, 0.946. The diagnostic efficiency is the best for infant-toddlers with profound hearing loss, with a sensitivity of 89.6% and a specificity of 88.4%. The more severe the hearing loss, the higher the discrimination accuracy of IT-MAIS and the better the diagnostic efficiency. Conclusion:The logistic model based on the IT-MAIS scale and the ROC curve method have a good efficiency in the diagnosis of hearing loss severity in infants and toddlers aged 0-36 months. When the child cannot cooperate with behavioral audiometry, the results of behavioral audiometry are unreliable, and there is no electrophysiological condition, the IT-MAIS scale is expected to evaluate the degree of infants' hearing loss as an auxiliary tool. It can understand the children's auditory function state more and provides a basis for the subsequent formulation of rehabilitation intervention strategies with certain clinical application value.

Prevalence of sleep impairment in patients with tinnitus: a systematic review and single-arm meta-analysis.

PURPOSE: This study aimed to comprehensively review the literature and synthesize relevant data to examine the pooled prevalence of poor sleep quality (sleep impairment) and assess overall sleep quality in patients with tinnitus. METHODS: This meta-analysis systematically searched both English (PubMed, Embase, and Web of Science) and Chinese (Wanfang Data Chinese database, Veep Chinese Database, and Chinese National Knowledge Infrastructure) databases. Data extraction and quality assessment were independently performed by two authors. The pooled prevalence of sleep impairment and poor sleep quality was calculated via a random-effects model. Sub-group and sensitivity analyses were performed to explore the source of heterogeneity. RESULTS: A total of seven studies were included with a total sample of 3041 tinnitus participants. The pooled prevalence of sleep impairment was 53.5% (95% confidence interval: 40.2-66.8%) and the I2 was 97.8% (Q = 7.90, p = 0.000). There were significant differences in the prevalence of poor sleep quality between males and females (39.1% vs. 44.6%, P = 0.034), between different PSQI cut-off values ≥ 7 and > 5 (53.1% vs. 53.8%, P = 0.000), and between sample sizes > 200 and ≤ 200 (54.0% vs. 52.7%, P = 0.000). In non-Asia area, the prevalence (56.6%, 95% CI: 42.6-70.5%) was lower than that in Asia areas (34.5%, 95% CI: 25.7-43.3%). CONCLUSION: Sleep impairment is common among patients with tinnitus. Development of interventions for conditions associated with poor sleep quality should be recommended to offer a safe and efficacious solution for this population.

Mechanism and modeling of hexavalent chromium interaction with a typical black soil: the importance of the relationship between adsorption and reduction.

Black soils have a significant retention effect on the migration of Cr(vi) towards groundwater, and Cr(vi) adsorption and reduction are both involved in this process. However, the adsorption and reduction of Cr(vi) were always investigated separately in previous studies resulting in an unclear relationship between them. In this study, the adsorption and reduction kinetic processes of Cr(vi) by a typical black soil were separately investigated under different initial Cr(vi) concentrations (40-400 mg L-1) and pH conditions (3.5-7.0) by the means of desorption treatment, and the equilibrium relationship between aqueous and adsorbed Cr(vi) was innovatively established based on the kinetic data. It was found that under pH 5.7 the adsorbed Cr(vi) content on soil particles was linearly correlated with the remaining Cr(vi) concentration in solution with time (R 2 = 0.98), and the reduction rate of Cr(vi) in the reaction system was linearly correlated with the adsorbed Cr(vi) content on soil particles with time (R 2 = 0.99). With pH decreasing from 7.0 to 3.5, the partition of Cr(vi) between solid and aqueous phases turned out to be of a non-linear nature, which can be fitted better by the Freundlich model. The retention of Cr(vi) by black soil was determined to follow the "adsorption-reduction" mechanism, where the Cr(vi) was first rapidly adsorbed onto the soil particles by a reversible adsorption reaction, and then the adsorbed Cr(vi) was gradually reduced into Cr(iii). A two-step kinetic model was developed accordingly, and the experimental data were fitted much better by the two-step adsorption-reduction kinetic model (R 2 = 0.89 on average) compared with the traditional first-order and second-order kinetic models (R 2 = 0.66 and 0.76 on average respectively). This paper highlights the novel two step kinetic model developed based on the proposed "adsorption-reduction" mechanism of Cr(vi) retention by a typical black soil.

Molecular structure-reactivity correlations of humic acid and humin fractions from a typical black soil for hexavalent chromium reduction.

Different soil humus fractions are structurally distinct from each other molecularly, however, the relationship between their microscopic molecular structures and the macroscopic reduction of Cr(VI) is still unknown, especially for the humin fraction. In this study, different humus fractions (HA, humic acid; HMi, humin linked to iron oxides; HMc, humin linked to clay; and HMr, humin residue) were sequentially extracted from a typical black soil and well characterized. It was found that HA, HMi and HMc were the same type of humus with similar molecular structures, while HMr was structurally different from the other fractions with a high cellulose content. The removal rate of Cr(VI) in solution decreased with progressive humus fractionation, namely, HA > HMi > HMc > HMr. Based on the two-dimensional correlation spectroscopic analysis (2DCOS) of the FTIR data, the changing functional groups of all humus fractions during reacting with Cr(VI) followed a similar order: carboxyl > phenol > hydroxyl > methyl > methylene. According to the correlation analysis, Cr(VI) reduction rates by different humus fractions were mainly determined by the content of phenol (R2 = 0.99) instead of carboxyl (R2 = 0.28). Except for HMr, the Cr(VI) reduction rates of different humus fractions were also positively correlated with surface and bulk polarity (R2 = 0.98 and 0.99) but not with aromaticity or aliphaticity (R2 = 0.21).

The influence of pH, co-existing ions, ionic strength, and temperature on the adsorption and reduction of hexavalent chromium by undissolved humic acid.

The retention of Cr(VI) in subsurface environment is highly dependent on humic acid (HA), however, the undissolved form is poorly investigated, the amount of which can be of two magnitude higher compared with the dissolved one in soils and sediments. In this study, the effects of time, initial concentration, pH, ionic strength, ion species and temperature on the adsorption and reduction respective processes by undissolved self-extracted peat soil HA from Northeast China (EHA) and from Sigma Aldrich (CHA) were investigated by batch experiments. Cr(VI) removal rates by EHA were higher than CHA and the maximum Cr(VI) removal amount for EHA and CHA were 0.77 (±0.01) and 0.61 (±0.02) mmol/g. Of these, 98% and 54% were reduced to Cr(III) by EHA and CHA respectively, which were related to the phenolic group content of HA. With time, the adsorbed Cr(VI) on HA increased to a maximum level (equilibrium) beyond which Cr(VI) reduction dominated the removal process. Cr(VI) adsorption and reduction by undissolved HA increased as pH decreased. Co-existing ion species had varying effect on Cr(VI) adsorption and indirectly on reduction especially divalent cations which was suggestive of cation bridging between Cr anions and ionized carboxyl group of HA. The positive effect of ionic strength (Ca2+) on Cr(VI) adsorption through complexation corroborated the cation bridge effect of divalent cations. Temperature increased both Cr(VI) adsorption (complexation) and reduction with enhancing reduction rate constants and partitioning. ΔHo, ΔSo, and ΔG° parameters showed that Cr(VI) adsorption and reduction processes were endothermic, irreversible and spontaneous.

Reduction mechanism of hexavalent chromium by functional groups of undissolved humic acid and humin fractions of typical black soil from Northeast China.

Soil organic matters (SOM) have a great retention effect on Cr(VI) migration in subsurface environment, which act as the main electron donors for Cr(VI) reduction; however, Cr(VI) reduction mechanism by different SOM fractions is still unclear, such as undissolved humic acid (HA) and humin (HM). In this study, HA and HM fractions extracted from typical black soil from Northeast China were used to investigate the reaction mechanism between humus functional groups and Cr(VI). According to the results, phenol and hydroxyl were determined as the main electron donors for Cr(VI) reduction by HA and HM instead of carboxyl and carbonyl, which were more likely involved in Cr complexation. Furthermore, Cr(VI) reduction was more dependent on aromatic carbon, rather than aliphatic carbon, and functional groups on the particle surfaces of HA and HM were much more active for Cr(VI) reduction than their interior part. Additionally, HM was found to have a relatively low Cr(VI) reduction capability compared with HA resulting from its high content of cellulose structures that are quite resistant to Cr(VI) oxidation. These results suggest that in the soil environment, undissolved HA tends to play a much more important role than HM in Cr(VI) reduction and retention in the condition that their mass contents are comparable.

The role of different functional groups in a novel adsorption-complexation-reduction multi-step kinetic model for hexavalent chromium retention by undissolved humic acid.

Undissolved humic acid (HA) has a great retention effect on the migration of hexavalent chromium [Cr(VI)] in soil, and HA functional groups play a predominant role in this process. However, the coupled mode between Cr(VI) retention and HA functional groups reaction is still unclear. In this study, it was found that a fair amount of Cr on HA existed in the forms of ion exchangeable and binding Cr(VI) during the reaction resulting from the ion exchange adsorption and complexation of Cr(VI). According to the results of two-dimensional correlation spectroscopic analysis (2DCOS), HA functional groups participated in the reaction with Cr(VI) in the order of carboxyl ≈ chelated carboxyl > phenol > polysaccharide > methyl, and all the functional groups were more likely to be located at aromatic domains. Based on the results of XPS spectra, rather than to be oxidized by Cr(VI), carboxyl more tended to be complexed by chromium, which is regarded as the precondition for Cr(VI) reduction. Phenol, polysaccharide and methyl with distinct reaction activities successively acted as major electron donors for Cr(VI) reduction in different reaction stages. Consequently, it was determined that the retention of Cr(VI) by undissolved HA followed an adsorption-complexation-reduction mechanism, and based on this, a multi-step kinetic model with multiple types of complexation/reduction sites was developed to simulate the retention processes resulting in a much better fitting effect (R2 > 0.99) compared with traditional first-order and second-order kinetic models (R2 < 0.95). This demonstrated that the multi-step kinetic model is of great potential in accurately simulating the migration and transformation of Cr(VI) in soil environment.

A novel method of three-dimensional hetero-spectral correlation analysis for the fingerprint identification of humic acid functional groups for hexavalent chromium retention.

Two-dimensional hetero-spectral correlation analysis has been widely used for the interpretation of spectral changes of humic substances involved in various environmental processes. However, when three different types of spectroscopies are utilised, only a pairwise correlation can be achieved. In order to overcome this problem, a novel method of three-dimensional hetero-spectral correlation analysis with scaling technique was developed in this study, which can further establish a direct correlation between three different types of spectroscopies, including FTIR, 13C CP/MAS NMR, and XPS. The proposed method was applied to the fingerprint identification of undissolved humic acid functional groups for Cr(vi) retention, which is one of the most important points for understanding the migration and transformation of Cr(vi) in a subsurface environment. The results indicated that mainly free and dissociated carboxylic groups, phenolic groups, and polysaccharide participated in the reaction with Cr(vi), and these functional groups were mainly located at aromatic domains. Besides, the variations of functional groups were related to the reduction of Cr(vi), and the reduced Cr(iii) mainly bound to aromatic domains. The successful application of the proposed method demonstrated that it can serve as a promising tool for further investigations concerning more complicated environmental processes and even other scientific fields by supplying more detailed, reliable and visualised spectral information.

Mechanism study of humic acid functional groups for Cr(VI) retention: Two-dimensional FTIR and 13C CP/MAS NMR correlation spectroscopic analysis.

Undissolved humic acid (HA) is known to substantially effect the migration and transformation of hexavalent chromium [Cr(VI)] in soils. The mechanisms of Cr(VI) retention in soils by undissolved HA have been reported; however, past studies are inconclusive about the types of HA functional groups that are involved in Cr(VI) retention and the retention mechanisms. Utilizing a two-dimensional correlation spectroscopy (2DCOS) analysis for FTIR and 13C CP/MAS NMR, this study investigated the variations of HA function groups and molecular structures after reactions with aqueous Cr(VI) under different pH conditions. Based on the changing sequence of functional groups interpreted from the 2DCOS results, a four-step mechanism for Cr(VI) retention was determined as follows: (1) electrostatic adsorption of Cr(VI) to HA surface, (2) complexation of adsorbed Cr(VI) by carboxyl and ester, (3) reduction of complexed Cr(VI) to Cr(III) by phenol and polysaccharide, and (4) complexation of reduced Cr(III) by carboxylic groups. These functional groups that are involved in Cr(VI) retention were determined to occur in aromatic domains.