Structure-based development of 3,5-dihydroxybenzoyl-hydrazineylidene as tyrosinase inhibitor; in vitro and in silico study.

A series of new analogs of 3,5-dihydroxybenzoyl-hydrazineylidene conjugated to different methoxyphenyl triazole (11a-n) synthesized using click reaction. The structures of all synthesized compounds were characterized by FTIR, 1H, 13C-NMR spectroscopy, and CHO analysis. The tyrosinase inhibitory potential of the synthesized compounds was studied. The newly synthesized scaffolds were found to illustrate the variable degree of the inhibitory profile, and the most potent analog of this series was that one bearing 4-methoxyphenyl moiety, and exhibited an IC50 value of 55.39 ± 4.93 µM. The kinetic study of the most potent derivative reveals a competitive mode of inhibition. Next, molecular docking studies were performed to understand the potent inhibitor's binding mode within the enzyme's binding site. Molecular dynamics simulations were accomplished to further investigate the orientation and binding interaction over time and the stability of the 11m-tyrosinase complex.

Synthesis and characterization of new biocatalyst based on LDH functionalized with l-asparagine amino acid for the synthesis of tri-substituted derivatives of 2, 4, 5-(H1)-imidazoles.

In this study, a new and recyclable biocatalyst (MgAl CO3-LDH@Asn) was synthesized by immobilizing l-asparagine amino acid (Asn) on the surface of 3-(chloropropyl)-trimethoxysilane modified MgAl CO3-layered double hydroxide (LDH). The physicochemical properties of the samples were identified by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and thermogravimetric analysis (TGA) techniques. The MgAl CO3-LDH@Asn was employed in the multi-component assembly process for the synthesis of tri-substituted derivatives of 2,4,5-(H1)-imidazoles from benzyl, various benzaldehyde derivatives, and ammonium acetate. For optimizing the reaction, the main factors, including the amount of MgAl CO3-LDH@Asn, type of solvent, reaction time, and temperature were evaluated. The optimum conditions of the model reaction were achieved using 20 mg of MgAl CO3-LDH@Asn biocatalyst in ethanol solvent after 20 min at reflux temperature. According to the findings above, the results indicated that high-yield products are achieved within a short time frame. Moreover, the high catalytic activity of the MgAl CO3-LDH@Asn was maintained for four cycles without significantly diminishing its performance.

Efficient synthesis of 3-alkyl-2-(-1H-1,2,3-triazolyl)methyl)thio)-2,3-dihydroquinazolin-4(1H)-one derivative via multistep synthesis approach by novel Cu@Py-Oxa@SPION catalyst.

In this pared, an efficient method is introduced for the synthesis of 3-alkyl-2-(((4-(2-oxopropyl)-1H-1,2,3-triazol-1-yl)alkyl)thio)-2,3-dihydroquinazolin-4(1H)-one derivatives. These novel products have both 1,2,3-triazole and quinazolinone in their structures. For the synthesis of these products, a novel catalyst is designed, synthesized, and characterized by the immobilization of copper onto modified magnetic iron oxide. The catalyst (denoted: Cu@Py-Oxa@SPION) was characterized by several characterization techniques. In this regard, 16 3-alkyl-2-(((4-(2-oxopropyl)-1H-1,2,3-triazol-1-yl)alkyl)thio)-2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized in high isolated yields (77-86%). As an advantage, the catalyst is highly recoverable and its activity has not decreased after 7 sequential runs. The method is very efficient for the synthesis of the products in high isolated yields under mild reaction conditions in a green solvent. The scope of the method is broad and several examples were successfully synthesized using starting materials with different functional groups.

Thiazolopyrimidine derivatives as novel class of small molecule tyrosinase inhibitor.

Tyrosinase, the rate-limiting enzyme of melanogenesis, plays a crucial role in hyperpigmentation. As a result, in this study, a novel class of thiazolopyrimidine derivatives was developed and synthesized as tyrosinase inhibitor. The structure of derivatives was characterized using various spectroscopy techniques, including FTIR, Mass, 1H-NMR, and 13C-NMR. Next, the inhibitory activities of all derivatives were examined against tyrosinase, and, 6a as the most potent compound, exhibited an IC50 value of 28.50 µM. Furthermore, the kinetic study of 6a was performed to better understand the inhibitory mechanism and its type of inhibition. The UV/Vis spectra analysis was also executed to provide valuable evidence supporting the inhibitory mechanism of compound 6a in the context of tyrosinase inhibition. Also, molecular docking and dynamic molecular study of 6a were executed to study its interactions within the enzyme's binding site.

High-Throughput Exploration of Triple-Cation Perovskites via All-in-One Compositionally-Graded Films.

Many devices heavily rely on combinatorial material optimization. However, new material alloys are classically developed by studying only a fraction of giant chemical space, while many intermediate compositions remain unmade in light of the lack of methods to synthesize gapless material libraries. Here report a high-throughput all-in-one material platform to obtain and study compositionally-tunable alloys from solution is reported. This strategy is applied to make all Csx MAy FAz PbI3 perovskite alloys (MA and FA stand for methylammonium and formamidinium, respectively), in less than 10 min, on a single film, on which 520 unique alloys are then studied. Through stability mapping of all these alloys in air supersaturated with moisture, a range of targeted perovskites are found, which are then chosen to make efficient and stable solar cells in relaxed fabrication conditions, in ambient air. This all-in-one platform provides access to an unprecedented library of compositional space with no unmade alloys, and hence aids in a comprehensive accelerated discovery of efficient energy materials.

Perceptual Doping: A Hypothesis on How Early Audiovisual Speech Stimulation Enhances Subsequent Auditory Speech Processing.

Face-to-face communication is one of the most common means of communication in daily life. We benefit from both auditory and visual speech signals that lead to better language understanding. People prefer face-to-face communication when access to auditory speech cues is limited because of background noise in the surrounding environment or in the case of hearing impairment. We demonstrated that an early, short period of exposure to audiovisual speech stimuli facilitates subsequent auditory processing of speech stimuli for correct identification, but early auditory exposure does not. We called this effect "perceptual doping" as an early audiovisual speech stimulation dopes or recalibrates auditory phonological and lexical maps in the mental lexicon in a way that results in better processing of auditory speech signals for correct identification. This short opinion paper provides an overview of perceptual doping and how it differs from similar auditory perceptual aftereffects following exposure to audiovisual speech materials, its underlying cognitive mechanism, and its potential usefulness in the aural rehabilitation of people with hearing difficulties.

The contribution of transdiagnostic vulnerability factors in patients with chronic insomnia.

Introduction: Various transdiagnostic factors have been associated with insomnia severity. The current study aimed to predict insomnia severity based on a group of transdiagnostic factors including neuroticism, emotion regulation, perfectionism, psychological inflexibility, anxiety sensitivity, and repetitive negative thinking after controlling for depression/anxiety symptoms and demographic characteristics. Methods: Two hundred patients with chronic insomnia disorder were recruited from a sleep disorder clinic. Participants completed the Insomnia Severity Index (ISI), Clinical Perfectionism Questionnaire (CPQ), Acceptance and Action Questionnaire-II (AAQ-II), Anxiety Sensitivity Index-3 (ASI-3), Repetitive Thinking Questionnaire (RTQ-10), Big Five Inventory (BFI-10), Emotion Regulation Questionnaire (ERQ), and Depression Anxiety Stress Scale (DASS-21). Results: After controlling for the confounding variables (depression/anxiety symptoms and demographic characteristics), hierarchical multiple linear regression suggested the significant association of neuroticism (BFI), cognitive reappraisal (ERQ), personal standards (CPQ), evaluative concerns (CPQ), physical concerns (ASI), cognitive concerns (ASI), and repetitive negative thinking (RTQ) with insomnia severity. Discussion: The findings support the role of transdiagnostic factors, especially physical concerns, repetitive negative thinking, and neuroticism in chronic insomnia. Future research using longitudinal designs is required to verify the causal status of transdiagnostic variables.

Electron ionization mass spectrometry fragmentation routes of Chemical Weapons Convention-related organoarsenic compounds: Electron ionization and density functional theory studies.

RATIONALE: For unambiguous identification of Chemical Weapons Convention (CWC)-related chemicals in environmental and biological samples, access to mass spectra and expertise in spectral interpretation is required. As of today, there is no mass spectrum available for dialkyl alkylarsonodithioites in the literature. Therefore, it is essential to obtain spectral information about these compounds. METHODS: CWC-related organoarsenic compounds were synthesized and analyzed by gas chromatography combined with mass spectrometry (MS), and their retention index (RI) was calculated by Van Den Dool's method. The relationship between RI and density functional theory (DFT)-calculated polarizability (⍺) and molecular weight was also studied. Electron ionization (EI) mode was used to investigate the general fragmentation patterns of the synthesized compounds. A DFT analysis of some major fragment ions was performed in order to confirm the fragmentation pathways. RESULTS: A linear relationship between RI and ⍺ is observed. The mass spectra of compounds 5-7 are affected by alkyl groups on sulfur and arsenic atoms. The molecular ions of compounds 5-7 can be observed in their EI-MS spectra with relatively good abundance. EI-MS studies revealed some interesting fragmentation pathways, such as the formation of arsenic analogue of benzylic and tropylium cations in EI-MS of chemicals 6. CONCLUSIONS: By analyzing the mass spectra and RI values, it is possible to detect CWC-related chemicals in aqueous, blood and urine samples during an on-site or off-site inspection.

Hearing loss, hearing aid use, and performance on the Montreal cognitive assessment (MoCA): findings from the HUNT study in Norway.

Purpose: To evaluate the associations between hearing status and hearing aid use and performance on the Montreal Cognitive Assessment (MoCA) in older adults in a cross-sectional study in Norway. Methods: This study utilized data from the fourth wave of the Trøndelag Health Study (HUNT4, 2017-2019). Hearing thresholds at frequencies of 0.5, 1, 2, and 4 kHz (or PTA4) in the better hearing ear were used to determine participants' hearing status [normal hearing (PTA4 hearing threshold, ≤ 15 dB), or slight (PTA4, 16-25 dB), mild (PTA4, 26-40 dB), moderate (PTA4, 41-55 dB), or severe (PTA4, ≥ 56 dB) hearing loss]. Both standard scoring and alternate MoCA scoring for people with hearing loss (deleting MoCA items that rely on auditory function) were used in data analysis. The analysis was adjusted for the confounders age, sex, education, and health covariates. Results: The pattern of results for the alternate scoring was similar to that for standard scoring. Compared with the normal-hearing group, only individuals with moderate or severe hearing loss performed worse in the MoCA. In addition, people with slight hearing loss performed better in the MoCA than those with moderate or severe hearing loss. Within the hearing loss group, hearing aid use was associated with better performance in the MoCA. No interaction was observed between hearing aid use and participants' hearing status with performance on the MoCA test. Conclusion: While hearing loss was associated with poorer performance in the MoCA, hearing aid use was found to be associated with better performance in the MoCA. Future randomized control trials are needed to further examine the efficacy of hearing aid use on the MoCA performance. When compared with standard scoring, the alternate MoCA scoring had no effect on the pattern of results.

Frailty and Mental Health Disorders Before and During COVID-19 Occurrence in Older Population in Iran: A Longitudinal Repeated-Measures Study.

PURPOSE: Iranians' worry over the number of older patients negatively impacted by COVID-19 surged dramatically throughout the 5 waves of the COVID-19 pandemic, which lasted from January 2020 to September 2021. The goal of this research was to assess the physical and mental health of Iranian older persons throughout the COVID-19 pandemic's major waves. METHODS: The health condition of 507 older persons with a positive examination for COVID-19 illness was assessed before and throughout the 5 waves of coronavirus in south Iran in analytical and hybrid longitudinal research. RESULTS: The primary consequences of COVID-19 incidence on frailty and mental health issues were revealed in this investigation. Using a linear mixed model, we found a reduction of 0.33 in loneliness (ß = -.33, 95% CI -0.39 to -0.26) during the COVID-19 pandemic. The probabilities of becoming depressed, anxious, or frail rose 4.61 (95% CI: 3.77-5.63), 1.85 (95% CI: 1.52-2.24), as well as 1.42 (95% CI: 1.17-1.42) time, subsequently, with COVID-19 occurrence, according to the mixed logistic models. Furthermore, the influence of COVID-19 incidence on loneliness result differs by gender; for depression, it varies by education; and for anxiety, it changes by comorbidities and living independently. CONCLUSION: The COVID-19 pandemic significantly impacts the mental health and frailty of older persons with the positive COVID-19 situation, and this scenario is gender-based too.

High-Throughput Synthesis of Thin Films for the Discovery of Energy Materials: A Perspective.

Thin films are an integral part of many electronic and optoelectronic devices. They also provide an excellent platform for material characterization. Therefore, strategies for the fabrication of thin films are constantly developed and have significantly benefited from the advent of high-throughput synthesis (HTS) platforms. This perspective summarizes recent advances in HTS of thin films from experimentalists' point of view. The work analyzes general strategies of HTS and then discusses their use in developing new energy materials for applications that rely on thin films, such as solar cells, light-emitting diodes, batteries, superconductors, and thermoelectrics. The perspective also summarizes some key challenges and opportunities in the HTS of thin films.

Psychopathology and Poor Clinical Insight in Psychotic Patients: Does the Diagnosis Matter?

ABSTRACT: Poor clinical insight is one of the most common features of schizophrenia spectrum disorders and plays a critical role in prognosis and treatment. Considering the biological and phenomenological overlap between schizophrenia and bipolar I disorder with psychotic features (BID) and increasing incidents of methamphetamine-induced psychotic disorder (MIPD) patients in Iran, it is necessary to have a clear picture of insight among these three groups. The aim of the present study was to compare clinical insight and other aspects of illness among three different disorders: schizophrenia, BID, and MIPD. In addition, we sought to examine the relationship of the severity of psychotic symptoms with clinical insight in each group. A total of 115 male inpatients, including 48 persons diagnosed with schizophrenia, 35 persons diagnosed with BID, and 32 persons diagnosed with MIPD, were selected. All participants completed the Scale to Assess Unawareness of Mental Disorder and the Positive and Negative Syndrome Scale. The results of analysis of variance indicated that schizophrenia patients reported higher rates of illness duration and number of hospital admissions in comparison to the MIPD and BID groups. In addition, persons diagnosed with BID reported more of these outcomes than MIPD groups. However, the three groups showed similar patterns in terms of age of onset and educational, marital, and occupational statuses. The results also revealed that awareness of the disorder was more impaired in schizophrenia patients compared with BID and MIPD patients and in MIPD compared with BID groups. However, the level of awareness of the effect of medication, the awareness of social consequences, and the total score of clinical insight were similar across the three diagnostic groups. As expected, poor clinical insight was correlated with high levels of positive, negative, and cognitive symptoms in the schizophrenia group; with high levels of positive, cognitive, and depressive symptoms in the BID group; and with high levels of positive and excitement symptoms in MIPD. In addition, hierarchical linear regression analyses revealed that only cognitive symptoms in the schizophrenia group and excitement symptoms in the MIPD group significantly predicted the overall score of clinical insight. In the BID group, both cognitive and depressive symptoms significantly predicted clinical insight. These findings suggest that there are differing levels of poor clinical insight in schizophrenia, MIPD, and BID and that poor clinical insight found within each group may have different antecedents.

Is Having Hearing Loss Fundamentally Different? Multigroup Structural Equation Modeling of the Effect of Cognitive Functioning on Speech Identification.

OBJECTIVES: Previous research suggests that there is a robust relationship between cognitive functioning and speech-in-noise performance for older adults with age-related hearing loss. For normal-hearing adults, on the other hand, the research is not entirely clear. Therefore, the current study aimed to examine the relationship between cognitive functioning, aging, and speech-in-noise, in a group of older normal-hearing persons and older persons with hearing loss who wear hearing aids. DESIGN: We analyzed data from 199 older normal-hearing individuals (mean age = 61.2) and 200 older individuals with hearing loss (mean age = 60.9) using multigroup structural equation modeling. Four cognitively related tasks were used to create a cognitive functioning construct: the reading span task, a visuospatial working memory task, the semantic word-pairs task, and Raven's progressive matrices. Speech-in-noise, on the other hand, was measured using Hagerman sentences. The Hagerman sentences were presented via an experimental hearing aid to both normal hearing and hearing-impaired groups. Furthermore, the sentences were presented with one of the two background noise conditions: the Hagerman original speech-shaped noise or four-talker babble. Each noise condition was also presented with three different hearing processing settings: linear processing, fast compression, and noise reduction. RESULTS: Cognitive functioning was significantly related to speech-in-noise identification. Moreover, aging had a significant effect on both speech-in-noise and cognitive functioning. With regression weights constrained to be equal for the two groups, the final model had the best fit to the data. Importantly, the results showed that the relationship between cognitive functioning and speech-in-noise was not different for the two groups. Furthermore, the same pattern was evident for aging: the effects of aging on cognitive functioning and aging on speech-in-noise were not different between groups. CONCLUSION: Our findings revealed similar cognitive functioning and aging effects on speech-in-noise performance in older normal-hearing and aided hearing-impaired listeners. In conclusion, the findings support the Ease of Language Understanding model as cognitive processes play a critical role in speech-in-noise independent from the hearing status of elderly individuals.

Design and synthesis of phenoxymethybenzoimidazole incorporating different aryl thiazole-triazole acetamide derivatives as α-glycosidase inhibitors.

A novel series of phenoxymethybenzoimidazole derivatives (9a-n) were rationally designed, synthesized, and evaluated for their α-glycosidase inhibitory activity. All tested compounds displayed promising α-glycosidase inhibitory potential with IC50 values in the range of 6.31 to 49.89 µM compared to standard drug acarbose (IC50 = 750.0 ± 10.0 µM). Enzyme kinetic studies on 9c, 9g, and 9m as the most potent compounds revealed that these compounds were uncompetitive inhibitors into α-glycosidase. Docking studies confirmed the important role of benzoimidazole and triazole rings of the synthesized compounds to fit properly into the α-glycosidase active site. This study showed that this scaffold can be considered as a highly potent α-glycosidase inhibitor.

Hearing loss, hearing aid use, and subjective memory complaints: Results of the HUNT study in Norway.

Objective: This study aimed to explore the association between hearing loss severity, hearing aid use, and subjective memory complaints in a large cross-sectional study in Norway. Methods: Data were drawn from the fourth wave of the Trøndelag Health Study (HUNT4 Hearing, 2017-2019). The hearing threshold was defined as the pure-tone average of 0.5, 1, 2, and 4 kHz in the better ear. The participants were divided into five groups: normal hearing or slight/mild/moderate/severe hearing loss. Subjective self-reported short-term and long-term memory complaints were measured by the nine-item Meta-Memory Questionnaire (MMQ). The sample included 20,092 individuals (11,675 women, mean age 58.3 years) who completed both hearing and MMQ tasks. A multivariate analysis of variance (adjusted for covariates of age, sex, education, and health cofounders) was used to evaluate the association between hearing status and hearing aid use (in the hearing-impaired groups) and long-term and short-term subjective memory complaints. Results: A multivariate analysis of variance, followed by univariate ANOVA and pairwise comparisons, showed that hearing loss was associated only with more long-term subjective memory complaints and not with short-term subjective memory complaints. In the hearing-impaired groups, the univariate main effect of hearing aid use was only observed for subjective long-term memory complaints and not for subjective short-term memory complaints. Similarly, the univariate interaction of hearing aid use and hearing status was significant for subjective long-term memory complaints and not for subjective short-term memory complaints. Pairwise comparisons, however, revealed no significant differences between hearing loss groups with respect to subjective long-term complaints. Conclusion: This cross-sectional study indicates an association between hearing loss and subjective long-term memory complaints but not with subjective short-term memory complaints. In addition, an interaction between hearing status and hearing aid use for subjective long-term memory complaints was observed in hearing-impaired groups, which calls for future research to examine the effects of hearing aid use on different memory systems.

The Burden of Cancer in a Sample of Iranian Population.

BACKGROUND: We aimed at estimating the burden of cancer in Kurdistan Province, western Iran during 2011-2017. METHODS: In this cross-sectional study, incidence data extracted from the cancer registry system and death data were extracted from the system of registration and classification of causes of death of Kurdistan Province. We applied the WHO' methods to calculate the disability-adjusted life year (DALYs). RESULTS: The burden of cancer increased from a DALYs of 12309 in 2011 to 13969 in 2017, the YLL from 11644 in 2011 to 12951 in 2017 and the YLD from 665 in 2011 to 1018 in 2017. The top five cancers, according to DALYs (%) in both sex during 2011-2017 were: stomach (25%), lung (14%), liver (9%), esophagus (6%), and colon (6%). The most burden of cancer related to gastrointestinal tract (54% vs. 45%). Totally, more than 25% of DALYs were related to stomach cancer. CONCLUSION: The increasing DALYs of cancer in Kurdistan Province is one of the major public health concerns as in most developed countries. More than half of the burden of cancer in the Kurdistan Province is related to gastrointestinal tract. Stomach cancer, is accounting for more than 25% of the burden in both sexes. Urgent policy, management and public health measures such as general education, screening, early detection and effective treatment are recommended to reduce the burden of cancers and especially gastrointestinal tract malignancies.

The Burden of Stroke in Kurdistan Province, Iran From 2011 to 2017.

OBJECTIVES: The aim of this study was to calculate the burden of stroke in Kurdistan Province, Iran between 2011 and 2017. METHODS: Incidence data extracted from the hospital information system of Kurdistan Province and death data extracted from the system of registration and classification of causes of death were used in a cross-sectional study. The World Health Organization method was used to calculate disability-adjusted life years (DALYs). RESULTS: The burden of stroke increased from 2453.44 DALYs in 2011 to 5269.68 in 2017, the years of life lost increased from 2381.57 in 2011 to 5109.68 in 2017, and the years of healthy life lost due to disability increased from 71.87 in 2011 to 159.99 in 2017. The DALYs of ischaemic stroke exceeded those of haemorrhagic stroke. The burden of disease, new cases, and deaths doubled during the study period. The age-standardised incidence rate of ischaemic stroke and haemorrhagic stroke in 2017 was 21.72 and 20.72 per 100 000 population, respectively. CONCLUSIONS: The burden of stroke is increasing in Kurdistan Province. Since health services in Iran are based on treatment, steps are needed to revise the current treatment services for stroke and to improve the quality of services. Policy-makers and managers of the health system need to plan to reduce the known risk factors for stroke in the community. In addition to preventive interventions, efficient and up-to-date interventions are recommended for the rapid diagnosis and treatment of stroke patients in hospitals. Along with therapeutic interventions, preventive interventions can help reduce the stroke burden.

The Burden of Cardiovascular Diseases in the Kurdistan Province, Iran, from 2011 through 2017.

Background: Calculating the burden of diseases is essential for their monitoring. The burden of cardiovascular diseases in Kurdistan Province has not been reported. This study aimed at calculating the burden of cardiovascular diseases in the Kurdistan Province from 2011 through 2017. Methods: In this cross-sectional study, incidence data were extracted from registration systems. The methods of the World Health Organization (WHO) were employed to calculate disability-adjusted life years (DALYs) of cardiovascular diseases in the Kurdistan Province. DALYs were calculated by summing the years of life lost (YLLs) and the years of life lived with disability (YLDs) for sex, age group, and year. Results: The burden of cardiovascular diseases increased from 18569.1 DALYs in 2011 to 34929.8 DALYs in 2017. The highest increase and the largest decrease in DALY according to the all age-standardized DALYs index were related to acute myocardial infarction and heart failure in women, respectively. The highest DALYs in both sexes were in the age group of over 80 years. Conclusion: The burden of cardiovascular diseases is increasing in the Iranian province of Kurdistan. It is, therefore, essential to implement appropriate and adequate interventions such as lifestyle modification, extensive screening, public education promotion, and operational plan development. We hope our results will aid decision-makers in performing urgent interventions.

Synthesis and biological evaluation of new benzimidazole-1,2,3-triazole hybrids as potential α-glucosidase inhibitors.

In this study, a series of benzimidazole-1,2,3-triazole hybrids 8a-n as new α-glucosidase inhibitors were designed and synthesized. In vitro α-glucosidase inhibition activity results indicated that all the synthesized compounds (IC50 values ranging from 25.2 ± 0.9 to 176.5 ± 6.7 µM) exhibited more inhibitory activity in comparison to standard drug acarbose (IC50 = 750.0 ± 12.5 µM). Enzyme kinetic study on the most potent compound 8c revealed that this compound was a competitive inhibitor into α-glucosidase. Moreover, the docking study was performed in order to evaluation of interaction modes of the synthesized compounds in the active site of α-glucosidase and to explain structure-activity relationships of the most potent compounds and their corresponding analogs.

Generating and Detecting High-Frequency Liquid-Based Sound Resonances with Nanoplasmonics.

We use metal nanostructures (nanoplasmonics) excited with dual frequency lasers to generate and detect high-frequency (>10 GHz) sound wave resonances in water. The difference frequency between the two lasers causes beating in the intensity, which results in a drop in the transmission through the nanostructure when an acoustic resonance is excited. By observing the resonance frequency shifts with changing nanostructure size, the transition from slow to fast sound in water is inferred, which has been measured by inelastic scattering methods in the past. The observed behavior shows remarkable similarities to finite element simulations using a simple Debye model for sound velocity (without fitting parameters).