Psychological Inoculation for Credibility Assessment, Sharing Intention, and Discernment of Misinformation: Systematic Review and Meta-Analysis.

BACKGROUND: The prevalence of misinformation poses a substantial threat to individuals' daily lives, necessitating the deployment of effective remedial approaches. One promising strategy is psychological inoculation, which pre-emptively immunizes individuals against misinformation attacks. However, uncertainties remain regarding the extent to which psychological inoculation effectively enhances the capacity to differentiate between misinformation and real information. OBJECTIVE: To reduce the potential risk of misinformation about digital health, this study aims to examine the effectiveness of psychological inoculation in countering misinformation with a focus on several factors, including misinformation credibility assessment, real information credibility assessment, credibility discernment, misinformation sharing intention, real information sharing intention, and sharing discernment. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, we conducted a meta-analysis by searching 4 databases (Web of Science, APA PsycINFO, Proquest, and PubMed) for empirical studies based on inoculation theory and outcome measure-related misinformation published in the English language. Moderator analyses were used to examine the differences in intervention strategy, intervention type, theme, measurement time, team, and intervention design. RESULTS: Based on 42 independent studies with 42,530 subjects, we found that psychological inoculation effectively reduces misinformation credibility assessment (d=-0.36, 95% CI -0.50 to -0.23; P<.001) and improves real information credibility assessment (d=0.20, 95% CI 0.06-0.33; P=.005) and real information sharing intention (d=0.09, 95% CI 0.03-0.16; P=.003). However, psychological inoculation does not significantly influence misinformation sharing intention (d=-0.35, 95% CI -0.79 to 0.09; P=.12). Additionally, we find that psychological inoculation effectively enhances credibility discernment (d=0.20, 95% CI 0.13-0.28; P<.001) and sharing discernment (d=0.18, 95% CI 0.12-0.24; P<.001). Regarding health misinformation, psychological inoculation effectively decreases misinformation credibility assessment and misinformation sharing intention. The results of the moderator analyses showed that content-based, passive inoculation was more effective in increasing credibility and sharing intention. The theme of climate change demonstrates a stronger effect on real information credibility. Comparing intervention types showed that pre-post interventions are more effective for misinformation credibility assessment, while post-only interventions are better for credibility discernment. CONCLUSIONS: This study indicated that psychological inoculation enhanced individuals' ability to discern real information from misinformation and share real information. Incorporating psychological inoculation to cultivate an informed public is crucial for societal resilience against misinformation threats in an age of information proliferation. As a scalable and cost-effective intervention strategy, institutions can apply psychological inoculation to mitigate potential misinformation crises.

[Differential diagnosis of autism spectrum disorder and global developmental delay based on machine learning and Children Neuropsychological and Behavioral Scale]. / åŸºäºŽæœºå™¨å­¦ä¹ å’Œå„¿ç«¥ç¥žç»å¿ƒç†è¡Œä¸ºæ£€æŸ¥é‡è¡¨é‰´åˆ«å­¤ç‹¬ç—‡è°±ç³»éšœç¢å’Œå ¨é¢å‘è‚²è¿Ÿç¼“å„¿ç«¥çš„ç ”ç©¶.

OBJECTIVES: To investigate the efficacy and required indicators of Children Neuropsychological and Behavioral Scale-Revision 2016 (CNBS-R2016) in the differential diagnosis of autism spectrum disorder (ASD) and global developmental delay (GDD). METHODS: A total of 277 children with ASD and 415 children with GDD, aged 18-48 months, were enrolled as subjects. CNBS-R2016 was used to assess the developmental levels of six domains, i.e., gross motor, fine motor, adaptive ability, language, social behavior, and warning behavior, and a total of 13 indicators on intelligence age and developmental quotient (DQ) were obtained as the input features. Five commonly used machine learning classifiers were used for training to calculate the classification accuracy, sensitivity, and specificity of each classifier. RESULTS: DQ of warning behavior was selected as the first feature in all five classifiers, and the use of this indicator alone had a classification accuracy of 78.90%. When the DQ of warning behavior was used in combination with the intelligence age of warning behavior, gross motor, and language, it had the highest classification accuracy of 86.71%. CONCLUSIONS: Machine learning combined with CNBS-R2016 can effectively distinguish children with ASD from those with GDD. The DQ of warning behavior plays an important role in machine learning, and its combination with other features can improve classification accuracy, providing a basis for the efficient and accurate differential diagnosis of ASD and GDD in clinical practice.

Promoted CD4+ T cell-derived IFN-γ/IL-10 by photobiomodulation therapy modulates neurogenesis to ameliorate cognitive deficits in APP/PS1 and 3xTg-AD mice.

BACKGROUND: The immune system has been implicated in synaptic plasticity, inflammation, and the progression of Alzheimer's disease (AD). However, there were few studies on improving the niche microenvironment of neural stem cells (NSCs) in the brain of AD to promote adult hippocampal neurogenesis (AHN) by regulating the function of non-parenchymal immune cells. METHODS: The lymph nodes of amyloid precursor protein/presenilin 1 (APP/PS1) and 3xTg (APP/PS1/tau) mouse models of AD were treated with photobiomodulation therapy (PBMT) for 10 J/cm2 per day for 1 month (10 min for each day), T lymphocytes isolated from these two AD models were treated with PBMT for 2 J/cm2 (5 min for each time). The NSCs isolated from hippocampus of these two AD models at E14, and the cells were co-cultivated with PBMT-treated T lymphocyte conditioned medium for NSCs differentiation. RESULTS: Our results showed that PBMT treatment could promote AHN and reverse cognitive deficits in AD mouse model. The expression of interferon-γ (IFN-γ) and interleukin-10 (IL-10) was upregulated in the brain of these two AD models after PBMT treated, which was induced by the activation of Janus kinase 2 (JAK2)-mediated signal transducer and activator of transcription 4 (STAT4)/STAT5 signaling pathway in CD4+ T cells. In addition, elevated CD4+ T cell levels and upregulated transforming growth factor-ß1 (TGFß1)/insulin-like growth factors-1 (IGF-1)/brain-derived neurotrophic factor (BDNF) protein expression levels were also detected in the brain. More importantly, co-cultivated the PBMT-treated T lymphocyte conditioned medium with NSCs derived from these two AD models was shown to promote NSCs differentiation, which was reflected in the upregulation of both neuronal class-III ß-tubulin (Tuj1) and postsynaptic density protein 95 (PSD95), but the effects of PBMT was blocked by reactive oxygen species (ROS) scavenger or JAK2 inhibitor. CONCLUSION: Our research suggests that PBMT exerts a beneficial neurogenesis modulatory effect through activating the JAK2/STAT4/STAT5 signaling pathway to promote the expression of IFN-γ/IL-10 in non-parenchymal CD4+ T cells, induction of improvement of brain microenvironmental conditions and alleviation of cognitive deficits in APP/PS1 and 3xTg-AD mouse models.

Pulsed Microwave-Induced Thermoacoustic Shockwave for Precise Glioblastoma Therapy with the Skin and Skull Intact.

Glioblastoma has a dismal prognosis and is a critical and urgent health issue that requires aggressive research and determined clinical efforts. Due to its diffuse and infiltrative growth in the brain parenchyma, complete neurosurgical resection is rarely possible. Here, pulsed microwave-induced thermoacoustic (MTA) therapy is proposed as a potential alternative modality to precisely and effectively eradicate in vivo orthotopic glioblastoma. A nanoparticle composed of polar amino acids and adenosine-based agonists is constructed with high microwave absorbance and selective penetration of the blood-brain barrier (BBB) at the tumor site. This nanoparticle can activate the adenosine receptor on the BBB to allow self-passage and tumor accumulation. The nanoparticle converts absorbed microwaves into ultrasonic shockwaves via the thermoacoustic cavitation effect. The ultrasonic shockwave can mechanically destroy tumor cells within a short range with minimal damage to adjacent normal brain tissue due to the rapid decay of the ultrasonic shockwave intensity. The deep tissue penetration characteristics of the microwave and the rapid decay of the ultrasonic shockwave make MTA therapy a promising glioblastoma cure including intact skin and skull.

Ultrahigh Sensitive and Tumor-Specific Photoacoustography in NIR-II Region: Optical Writing and Redox-Responsive Graphic Fixing by AgBr@PLGA Nanocrystals.

The highly up-regulated glutathione (GSH) concentration in the tumor microenvironment is generally identified to be an effective endogenous characteristic of cancerous tissues. Herein, an ultrahigh-sensitive and tumor-specific photoacoustography technique in the near-infrared (NIR-II) region based on optical writing and redox-responsive chromogenic graphic fixing is developed by introducing a self-synthesized photosensitive silver bromide modified with poly lactic-co-glycolic acid (AgBr@PLGA) nanocrystals. After they are optically triggered by external light, the NIR-transparent AgBr@PLGA nanocrystals can be reduced by the tumor-abundant GSH into strongly absorbing silver nanoparticles, significantly boosting the "turn-on" photoacoustic (PA) signal in the NIR-II region; therefore, the tumor area can be graphically fixed and developed in the photoacoustography. Experiments on both in vitro phantoms and in vivo mouse models demonstrate that the tumor area is specifically identified by the photoacoustography with the background signals effectively suppressed by dynamically modulating the exposure time. The tumor-specific photoacoustography technique prefigures great potential for high-precision cancer diagnosis and treatment monitoring.

Photobiomodulation therapy promotes the ATP-binding cassette transporter A1-dependent cholesterol efflux in macrophage to ameliorate atherosclerosis.

Atherosclerosis is a chronic inflammatory disease related to a massive accumulation of cholesterol in the artery wall. Photobiomodulation therapy (PBMT) has been reported to possess cardioprotective effects but has no consensus on the underlying mechanisms. Here, we aimed to investigate whether PBMT could ameliorate atherosclerosis and explore the potential molecular mechanisms. The Apolipoprotein E (ApoE)-/- mice were fed with western diet (WD) for 18 weeks and treated with PBMT once a day in the last 10 weeks. Quantification based on Oil red O-stained aortas showed that the average plaque area decreased 8.306 ± 2.012% after PBMT (P < .05). Meanwhile, we observed that high-density lipoprotein cholesterol level in WD + PBMT mice increased from 0.309 ± 0.037 to 0.472 ± 0.038 nmol/L (P < .05) compared with WD mice. The further results suggested that PBMT could promote cholesterol efflux from lipid-loaded primary peritoneal macrophages and inhibit foam cells formation via up-regulating the ATP-binding cassette transporters A1 expression. A contributing mechanism involved in activating the phosphatidylinositol 3-kinases/protein kinase C zeta/specificity protein 1 signalling cascade. Our study outlines that PBMT has a protective role on atherosclerosis by promoting macrophages cholesterol efflux and provides a new strategy for treating atherosclerosis.

High-Fidelity CRISPR/Cas13a trans-Cleavage-Triggered Rolling Circle Amplified DNAzyme for Visual Profiling of MicroRNA.

The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) (CRISPR/Cas) system innovates a next-generation biosensor due to its high-fidelity, programmability, and efficient signal amplification ability. Developing a CRISPR/Cas-based visual detection system could contribute to point-of-care biomarker diagnosis. Existing CRISPR/Cas9-mediated visual detection methods are limited by the inherent properties of Cas9. Herein, we explored the trans-cleavage ability of Cas13a on ribonucleotide-bearing DNA oligo, eliminated the unavailability of the trans-cleavage substrate for subsequent polymerization reaction, and developed a homogeneous CRISPR/Cas13a-based visual detection system (termed vCas) for specific and sensitive detection of miRNA. The results indicated that vCas can provide a detection limit of 1 fM for miR-10b with single-base specificity and can be used to analyze miRNA in serum and cell extracts. Conclusively, vCas holds a great application prospective for clinical molecular diagnosis.

Spectral interferometric depth-resolved photoacoustic viscoelasticity imaging.

Viscoelasticity is closely related to the physiological characteristics of biological tissues. In this Letter, we propose a novel spectral interferometric depth-resolved photoacoustic viscoelasticity imaging (SID-PAVEI) method, to the best of our knowledge for the first time, which breaks the plight of surface viscoelasticity imaging and achieves an internal visible microscale SID-PAVEI in a noncontact fashion. In this work, we employ a high-sensitive and depth-resolved spectral domain low coherence interferometry (SDLCI) to remotely track photoacoustic-induced strain response of absorbers in situ. By decoupling the phase and amplitude of the photoacoustic-encoded spectral interference signal, the SID-PAVEI and scattering structure imaging (SSI) can be obtained simultaneously. Depth-resolved performance of the SID-PAVEI and the SSI in one scan were demonstrated by imaging biological tissues. The method opens new perspectives for three-dimensional microscale viscoelasticity imaging and provides a great potential in multi-parametric characterizing pathological information.

All-optical noncontact phase-domain photoacoustic elastography.

Mechanical properties such as elasticity are important indicators of tissue functions that can be used for clinical diagnosis and disease monitoring. However, most current elastography techniques are limited in their ability to distinguish localized microstructural mechanical variations due to employing elastic wave velocity measurement. In addition, their contact-based measurement manner is not favored and may even be prohibited in many applications. In this Letter, we propose all-optical noncontact phase-domain photoacoustic elastography (NPD-PAE), leveraging the temporal response characteristics of laser-induced thermoelastic displacement using optical interferometric detection to calculate the elastic modulus. The all-optical pump-probe method allows the capture of the initial displacement profiles generated at the origin, thus enabling the extraction of in situ elasticity. The feasibility of the method was verified using a tissue-mimicking phantom. The capability to map the mechanical contrast was demonstrated on an ex vivo biological tissue. NPD-PAE opens a new avenue for development of a noncontact elastography technique, holding great potential in the biomedical field and materials science.

Interleukin-17 upregulation participates in the pathogenesis of heart failure in mice via NF-κB-dependent suppression of SERCA2a and Cav1.2 expression.

Interleukin-17 (IL-17), also called IL-17A, is an important regulator of cardiac diseases, but its role in calcium-related cardiac dysfunction remains to be explored. Thus, we investigated the influence of IL-17 on calcium handling process and its contribution to the development of heart failure. Mice were subjected to transaortic constriction (TAC) to induce heart failure. In these mice, the levels of IL-17 in the plasma and cardiac tissue were significantly increased compared with the sham group. In 77 heart failure patients, the plasma level of IL-17 was significantly higher than 49 non-failing subjects, and was negatively correlated with cardiac ejection fraction and fractional shortening. In IL-17 knockout mice, the shortening of isolated ventricular myocytes was increased compared with that in wild-type mice, which was accompanied by significantly increased amplitude of calcium transient and the upregulation of SERCA2a and Cav1.2. In cultured neonatal cardiac myocytes, treatment of with IL-17 (0.1, 1 ng/mL) concentration-dependently suppressed the amplitude of calcium transient and reduced the expression of SERCA2a and Cav1.2. Furthermore, IL-17 treatment increased the expression of the NF-κB subunits p50 and p65, whereas knockdown of p50 reversed the inhibitory effects of IL-17 on SERCA2a and Cav1.2 expression. In mice with TAC-induced mouse heart, IL-17 knockout restored the expression of SERCA2a and Cav1.2, increased the amplitude of calcium transient and cell shortening, and in turn improved cardiac function. In addition, IL-17 knockout attenuated cardiac hypertrophy with inhibition of calcium-related signaling pathway. In conclusion, upregulation of IL-17 impairs cardiac function through NF-κB-mediated disturbance of calcium handling and cardiac remodeling. Inhibition of IL-17 represents a potential therapeutic strategy for the treatment of heart failure.

Efficacy and safety of ultrasound-guided quadratus lumborum block in patients receiving percutaneous nephrolithotomy under general anaesthesia.

PURPOSE: The aim of this study was to explore the overall efficacy and safety of ultrasound-guided quadratus lumborum block combined with general anaesthesia in patients undergoing percutaneous nephrolithotomy (PCNL). METHODS: The study included 76 patients who underwent PCNL at our hospital between October 2018 and October 2019. The patients were randomly divided into the study group (ultrasound-guided quadratus lumborum block combined with general anaesthesia, 38 cases) and the control group (general anaesthesia, 38 cases). The intra-operative estimated blood loss, operative time and intra-operative anaesthetic usage were recorded. Moreover, the effective pressing times of the posterior cerebral artery (PCA) and the dosage of sufentanil in patient-controlled intravenous analgesia (PCIA) were observed within 48 hours after operation. RESULTS: The dosage of propofol and remifentanil, the time of intestinal exhaust recovery time and the hospital study in the study group were lower than those in the control group. The HR and MAP of the two groups, with a trend towards gradual decrease at T0 and T1, were lower than those at T0. At 2, 6, 8 and 24 hours after operation, the visual analogue scale/score (VAS) of the study group was lower than that of the control group. The analgesic rescue rate, the dosage of sufentanil and the effective PCA compression times in the study group were lower than those in the control group. The total incidence of adverse reactions in postanaesthesia care unit in the study group was significantly lower than that in the control group (8/38 vs 18/38). CONCLUSION: The combination of ultrasound-guided quadratus lumborum block and general anaesthesia effectively exerts beneficial outcomes in terms of validly reducing the dose of tranquilisers and anaesthetic analgesics during PCNL, which is able to treat patients with anaesthetic mode of low opioids.

Photoacoustic Cavitation-Ignited Reactive Oxygen Species to Amplify Peroxynitrite Burst by Photosensitization-Free Polymeric Nanocapsules.

Photoacoustic (PA) technology can transform light energy into acoustic wave, which can be used for either imaging or therapy that depends on the power density of pulsed laser. Here, we report photosensitizer-free polymeric nanocapsules loaded with nitric oxide (NO) donors, namely NO-NCPs, formulated from NIR light-absorbable amphiphilic polymers and a NO-releasing donor, DETA NONOate. Controlled NO release and nanocapsule dissociation are achieved in acidic lysosomes of cancer cells. More importantly, upon pulsed laser irradiation, the PA cavitation can excite water to generate significant reactive oxygen species (ROS) such as superoxide radical (O2.- ), which further spontaneously reacts with the in situ released NO to burst highly cytotoxic peroxynitrite (ONOO- ) in cancer cells. The resultant ONOO- generation greatly promotes mitochondrial damage and DNA fragmentation to initiate programmed cancer cell death. Apart from PA imaging, PA cavitation can intrinsically amplify reactive species via photosensitization-free materials for promising disease theranostics.

Multi-parameter characterization of atherosclerotic plaques based on optical coherence tomography, photoacoustic and viscoelasticity imaging.

Detection of atherosclerotic plaque vulnerability is the critical step in prevention of acute coronary events. Fibrous cap thickness, lipid core size, and inflammation extent are three key parameters for assessing plaque vulnerability. Here, we report on multimodality imaging of mice aortic plaques using a system that integrates optical coherence tomography (OCT), photoacoustic imaging (PAI), and photoacoustic viscoelasticity imaging (PAVEI). The thickness of fibrous cap is accurately evaluated by OCT, and PAI helps to determine the distribution and size of lipid core. The mechanical properties of plaques are closely related to the plaque compositions and the content and distribution of macrophages, while PAVEI can characterize the plaque viscoelasticity through the phase delay of photoacoustic signal. Experimental results demonstrate that the OCT-PAI-PAVEI system can comprehensively characterize the three traits of atherosclerotic plaques, thereby identifying high-risk lesions.

Pulsed Microwave-Pumped Drug-Free Thermoacoustic Therapy by Highly Biocompatible and Safe Metabolic Polyarginine Probes.

Serious side effects are plaguing traditional chemotherapy, and the development of drug-free treatment is expected to ease the dilemma. Herein, drug-free polyarginine probes are fabricated from the co-polymerization of arginine monomer and slight amount of rhodamine B monomer, which are efficient for thermoacoustic imaging and therapy with high biocompatibility and safe metabolism. Polyarginine can be strongly pumped upon pulsed microwave irradiation, generating significant thermoacoustic shockwaves, namely thermocavitation, which can in situ destroy mitochondria to initiate programmed cancer cell apoptosis. In vivo explorations demonstrate the high theranostic efficiency for cancer thermoacoustic imaging and cancer inhibition, exhibiting low systemic cytotoxicity and good biocompatibility after systemic administration. Herein, pulsed microwave-pumped biocompatible polyarginine is promising for drug-free precision theranostics without any detectable side effects, and the deep penetration potency of microwave makes it potentially able to treat deep-seated diseases in future biomedicine.

Systemic effect of dietary lipid levels and α-lipoic acid supplementation on nutritional metabolism in zebrafish (Danio rerio): focusing on the transcriptional level.

Considering the excessive lipid accumulation status caused by the increased dietary lipid intake in farmed fish, this study aimed to investigate the systemic effect of dietary lipid levels and α-lipoic acid supplementation on nutritional metabolism in zebrafish. A total of 540 male zebrafish (0.17 g) were fed with normal (CT) and high lipid level (HL) diets for 6 weeks, then fed on 1000 mg/kg α-lipoic acid supplementation diets for the second 6 weeks. HL diets did not affect whole fish protein content, but increased ASNS expression (P < 0.05). Dietary α-lipoic acid increased whole fish protein content, and decreased the expressions of protein catabolism-related genes in muscle of high lipid level groups (P < 0.05). Furthermore, HL diets increased the whole fish lipid content and the expressions of gluconeogenesis and lipogenesis-related genes (P < 0.05), and α-lipoic acid counteracted these effects and decreased the whole fish triglyceride and cholesterol contents and expressions of lipogenesis-related genes, with the enhanced expressions of lipolytic genes, especially in high lipid groups (P < 0.05). HL diets did not affect hepatocyte mitochondrial quantity or the mRNA expressions of mitochondrial biogenesis and electron transport chain-related genes; they were significantly increased by dietary α-lipoic acid (P < 0.05). These results indicated that high dietary lipid promotes lipid accumulation, while α-lipoic acid increases protein content in association of enhanced lipid catabolism. Thus, dietary α-lipoic acid supplementation could reduce lipid accumulation under high lipid, which provides a promising new approach in solving the problem of lipid accumulation in farmed fish.

Dynamic-Reversible Photoacoustic Probe for Continuous Ratiometric Sensing and Imaging of Redox Status in Vivo.

Here, we report a reversible photoacoustic (PA) probe, BDP-DOH, to image the localized redox state in vivo via monitoring the dynamic changes of the redox couple, superoxide anion (O2•-) and glutathione (GSH). The probe features a significant shift in absorption between 680 and 750 nm during selective oxidation with O2•- and the reductive recovery of GSH, thus showing a reversible responsiveness in the photoacoustic intensity ratio (PA750/PA680) to successfully visualize the redox status of the tissue in situ. This redox probe with specific and sensitive photoacoustic response provides a potential technical tool toward understanding pathological formation processes.

High-Fidelity and Rapid Quantification of miRNA Combining crRNA Programmability and CRISPR/Cas13a trans-Cleavage Activity.

MicroRNAs (miRNAs) are short noncoding RNAs that post-transcriptionally regulate gene expression. It has been proved that the aberrant expression of miRNAs is related to disease and miRNAs can serve as potential biomarkers for early tumor diagnosis. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a is a recently discovered CRISPR-RNA (crRNA) guided RNA manipulation tool. The recognition of target RNA can morphologically activate the robust nonspecific trans ribonuclease activity of Cas13a. This unique property makes Cas13a ideal for nucleic acid detection. Herein, we first exploited CRISPR/LbuCas13a to directly detect miRNAs with high specificity and simplicity. A limit of detection (LOD) as low as 4.5 amol was achieved by this one-step assay within 30 min, and the dynamic range spanned 4 orders of magnitude from 10 amol to 100 fmol. More importantly, single nucleotide variation, even at the end of target miRNA, can be discriminated by rationally programmed crRNA. In addition, the practical application ability of this Cas13a/crRNA-based signal amplification strategy was demonstrated by miRNA quantification in complex biological samples (total small RNA). With excellent reliability, sensitivity, and simple to implement features, this method promises a great potential for early diagnosis of miRNA-related disease. Moreover, the systematic analysis of the crRNA design could provide guidance to further develop Cas13a-based molecular diagnoses.

Pile-up effect in an infrared single-pixel compressive LiDAR system.

Compressive sensing (CS) has been used in LiDAR systems utilizing one single-photon-counting avalanche diode. We demonstrate an unexpected grayscale inversed image of an object at an unchosen depth, which appears in the reconstruction of the infrared single-pixel LiDAR system due to the pile-up effect. A correction algorithm and the sparse measurement are proposed and experimentally verified to effectively reduce the photon pile-up influence, so that the negative images can be completely removed. The correction methods in this research can improve the accuracy and the flexibility of the single-pixel LiDAR systems employing detectors with a low maximum light count.

Photoacoustic thermorelaxation microscopy for thermal diffusivity measurement.

Thermal diffusivity is one of the main parameters to characterize the thermo-physical properties of materials, and advances in its measurement technique will have significant impact on materials science and related applications. Here a photoacoustic (PA) thermorelaxation microscopy is proposed as a new noncontact method to measure the thermal diffusivity. By delivering co-focused heating/probing laser pulse pairs with tunable time delays, the sample's in situ thermal relaxation behavior after the heating pulse excitation can be photoacoustically monitored based on the temperature-dependent property of the Grueneisen parameter. We theoretically deduced the dependence of the obtained PA thermorelaxation time on the thermal diffusivity, and the results coincided well with simulations. The feasibility of this method was validated by various industrial and biological samples. This method provides a new strategy for high-resolution thermal diffusivity measurement with flexible measurement conditions, prefiguring great potential for material and biological applications.

Co-impulse multispectral photoacoustic microscopy and optical coherence tomography system using a single supercontinuum laser.

A combination of multispectral photoacoustic microscopy (PAM) and optical coherence tomography (OCT) by a single light source was previously realized discretely; however, this is unfavorable for visualizing vital physiological and pathological activities in vivo. Here, a co-impulse dual-mode imaging system that simultaneously enables multispectral PAM and OCT using a megahertz supercontinuum pulse laser in vivo is presented. The 500-600 nm band is used for functional PAM imaging, which can flexibly switch between different wavelengths, while the 600-840 nm band is selected for OCT imaging. A mimicking phantom experiment and in vivo imaging of normal and melanoma mouse ears demonstrate that the co-impulse multispectral PAM-OCT system can simultaneously provide structural and functional information for bioimaging.