Simultaneous photoacoustic and ultrasound imaging: A review.

Photoacoustic imaging (PAI) is an emerging biomedical imaging technique that combines the advantages of optical and ultrasound imaging, enabling the generation of images with both optical resolution and acoustic penetration depth. By leveraging similar signal acquisition and processing methods, the integration of photoacoustic and ultrasound imaging has introduced a novel hybrid imaging modality suitable for clinical applications. Photoacoustic-ultrasound imaging allows for non-invasive, high-resolution, and deep-penetrating imaging, providing a wealth of image information. In recent years, with the deepening research and the expanding biomedical application scenarios of photoacoustic-ultrasound bimodal systems, the immense potential of photoacoustic-ultrasound bimodal imaging in basic research and clinical applications has been demonstrated, with some research achievements already commercialized. In this review, we introduce the principles, technical advantages, and biomedical applications of photoacoustic-ultrasound bimodal imaging techniques, specifically focusing on tomographic, microscopic, and endoscopic imaging modalities. Furthermore, we discuss the future directions of photoacoustic-ultrasound bimodal imaging technology.

Small apes adjust rhythms to facilitate song coordination.

Song coordination is a universal characteristic of human music. Many animals also produce well-coordinated duets or choruses that resemble human music. However, the mechanism and evolution of song coordination have only recently been studied in animals. Here, we studied the mechanism of song coordination in three closely related species of wild Nomascus gibbons that live in polygynous groups. In each species, song bouts were dominated by male solo sequences (referred to hereafter as male sequence), and females contributed stereotyped great calls to coordinate with males. Considering the function of rhythm in facilitating song coordination in human music and animal vocalizations, we predicted that adult males adjust their song rhythm to facilitate song coordination with females. In support of this prediction, we found that adult males produced significantly more isochronous rhythms with a faster tempo in male sequences that were followed by successful female great calls (a complete sequence with "introductory" and "wa" notes). The difference in isochrony and tempos between successful great call sequences and male sequences was smaller in N. concolor compared with the other two species, which may make it difficult for females to predict a male's precise temporal pattern. Consequently, adult females of N. concolor produced more failed great call (an incomplete sequence with only introductory notes) sequences. We propose that the high degree of rhythm change functions as an unambiguous signal that can be easily perceived by receivers. In this regard, gibbon vocalizations offer an instructive model to understand the origins and evolution of human music.

4D spectral-spatial computational photoacoustic dermoscopy.

Photoacoustic dermoscopy (PAD) is an emerging non-invasive imaging technology aids in the diagnosis of dermatological conditions by obtaining optical absorption information of skin tissues. Despite advances in PAD, it remains unclear how to obtain quantitative accuracy of the reconstructed PAD images according to the optical and acoustic properties of multilayered skin, the wavelength and distribution of excitation light, and the detection performance of ultrasound transducers. In this work, a computing method of four-dimensional (4D) spectral-spatial imaging for PAD is developed to enable quantitative analysis and optimization of structural and functional imaging of skin. This method takes the optical and acoustic properties of heterogeneous skin tissues into account, which can be used to correct the optical field of excitation light, detectable ultrasonic field, and provide accurate single-spectrum analysis or multi-spectral imaging solutions of PAD for multilayered skin tissues. A series of experiments were performed, and simulation datasets obtained from the computational model were used to train neural networks to further improve the imaging quality of the PAD system. All the results demonstrated the method could contribute to the development and optimization of clinical PADs by datasets with multiple variable parameters, and provide clinical predictability of photoacoustic (PA) data for human skin.

Molecular Characterization and Marker Development of the HMW-GS Gene from Thinopyrum elongatum for Improving Wheat Quality.

The quality of wheat primarily depends on its storage protein quality, especially in regards to gluten content and high-molecular-weight glutenin subunits (HMW-GS). The number of HMW-GS alleles is limited in bread wheat (Triticum aestivum L.), whereas it is abundant in wheat relatives. Therefore, HMW-GS alleles from wheat relatives could provide a potential for improving quality in wheat breeding. Thinopyrum elongatum (EE) is one of the relatives of wheat. The E genome is closely related to the ABD genome in wheat; therefore, Th. elongatum is often used as an excellent exogenous gene donor for wheat genetic improvement. In this study, the high-molecular glutenin subunit gene was cloned and sequenced from Th. elongatum. A specific molecular marker for identifying the Glu-1Ey subunit gene was developed and applied to detected wheat-Th. elongatum alien introgression lines. Quality analysis indicated that the substitution and addition lines containing Th. elongatum alleles significantly (p < 0.05) increased grain protein content by 3.76% to 5.11%, wet-gluten content by 6.55% to 8.73%, flour 8-MW by 0.25% to 6.35%, and bread volume value by 33.77 mL to 246.50 mL, in comparing it with Chinese Spring. The GMP content and lactic acid SRC showed significant positive correlations with flour processing quality and might be used as indicators for wheat quality. The results were expected to provide a novel route for improving processing quality in wheat quality breeding.

Nakagami statistics-based photoacoustic spectroscopy used for label-free assessment of bone tissue.

Quick identification of abnormal molecular metabolism of bone tissues is challenging. Photoacoustic (PA) spectroscopy techniques have great potential in molecular imaging. However, most of them are amplitude-dependent and easily affected by the light deposition, especially for bone tissues with high optical scattering. In this Letter, we propose a Nakagami statistics-based PA spectroscopy (NSPS) method for characterizing molecules in bone tissues. We indicate that the NSPS curve can intelligently identify changes in the content of molecules in bone tissues, with a high disturbance-resisting ability. The NSPS has remarkable potential for use in the early and rapid detection of bone diseases.

Transfer of the Resistance to Multiple Diseases from a Triticum-Secale-Thinopyrum Trigeneric Hybrid to Ningmai 13 and Yangmai 23 Wheat Using Specific Molecular Markers and GISH.

The middle to lower reaches of the Yangtze River are China's second largest area for wheat production; wheat disease is more serious there than in other areas because of the high humidity and warm weather. However, most cultivated varieties are susceptible to Fusarium head blight (FHB), powdery mildew, and stripe rust, and the lack of disease-resistant germplasm is an obstacle in wheat breeding. Rye and Thinopyrum elongatum, related species of wheat, carry many genes involved in disease resistance. In this study, a trigeneric hybrid, YZU21, with resistance to FHB, powdery mildew, and stripe rust was used to improve two major wheat cultivars, Ningmai 13 (NM13) and Yangmai 23 (YM23). Specific molecular markers and GISH were used to identify hybrid progenies. Five addition or substitution lines and one translocation line of the Triticum-Secale-Thinopyrum trigeneric hybrid were obtained and evaluated for agronomic traits and the resistance to multiple diseases. The results showed that the six trigeneric hybrid lines had desirable agronomic traits and improved resistance to FHB, powdery mildew, and stripe rust; they might be used as parents in wheat breeding for the resistance to multiple disease.

Exploring and applying genes to enhance the resistance to Fusarium head blight in wheat.

Fusarium head blight (FHB) is a destructive disease in wheat worldwide. Fusarium graminearum species complex (FGSC) is the main causal pathogen causing severe damage to wheat with reduction in both grain yield and quality. Additionally, mycotoxins produced by the FHB pathogens are hazardous to the health of human and livestock. Large numbers of genes conferring FHB resistance to date have been characterized from wheat and its relatives, and some of them have been widely used in breeding and significantly improved the resistance to FHB in wheat. However, the disease spreads rapidly and has been severe due to the climate and cropping system changes in the last decade. It is an urgent necessity to explore and apply more genes related to FHB resistant for wheat breeding. In this review, we summarized the genes with FHB resistance and mycotoxin detoxication identified from common wheat and its relatives by using forward- and reverse-genetic approaches, and introduced the effects of such genes and the genes with FHB resistant from other plant species, and host-induced gene silencing (HIGS) in enhancing the resistance to FHB in wheat. We also outlined the molecular rationale of the resistance and the application of the cloned genes for FHB control. Finally, we discussed the future challenges and opportunities in this field.

Multiscale confocal photoacoustic dermoscopy to evaluate skin health.

Background: Photoacoustic dermoscopy (PAD) is a promising branch of photoacoustic microscopy (PAM) that can provide a range of functional and morphologic information for clinical assessment and diagnosis of dermatological conditions. However, most PAM setups are unsuitable for clinical dermatology because their single-scale mode and narrow frequency band result in insufficient imaging depth or poor spatiotemporal resolution when visualizing the internal texture of the skin. Methods: We developed a multiscale confocal photoacoustic dermoscopy (MC-PAD) with a multifunction opto-sono objective that could achieve high quality dermatological imaging. Using the objective to coordinate the spatial resolution and penetration depth, the MC-PAD was used to visualize pathophysiological biomarkers and vascular morphology from the epidermis (EP) to the dermis, which enabled us to quantify skin abnormalities without using exogenous contrast agents for human skin. Results: The MC-PAD was shown to have the ability to differentiate between different types of cells (such as red blood cells and melanoma cells), image and quantify pigment of the skin, and visualize skin morphology and blood capillary landmarks. The MC-PAD detected a significant difference in the structures of some pigmented and vascular lesions of skin diseases compared with that of healthy skin (P<0.01). The café au lait macule (CALM) skin type was found to have a relatively higher melanin concentration and thicker stratum basale (SB) in the EP than healthy skin. The dermal vascular network of skin that had a port wine stain (PWS) had greater diameters and a denser distribution than healthy skin, as reported in clinical trials. Conclusions: The MC-PAD has a broad range of applications for the diagnosis of human skin diseases and evaluation of the curative effect of treatments, and it can offer new perspectives in biomedical sciences.

Regulatory Mechanisms of Mitogen-Activated Protein Kinase Cascades in Plants: More than Sequential Phosphorylation.

Mitogen-activated protein kinase (MAPK) cascades play crucial roles in almost all biological processes in plants. They transduce extracellular cues into cells, typically through linear and sequential phosphorylation and activation of members of the signaling cascades. However, accumulating data suggest various regulatory mechanisms of plant MAPK cascades in addition to the traditional phosphorylation pathway, in concert with their large numbers and coordinated roles in plant responses to complex ectocytic signals. Here, we highlight recent studies that describe the uncanonical mechanism of regulation of MAPK cascades, regarding the activation of each tier of the signaling cascades. More particularly, we discuss the unusual role for MAPK kinase kinases (MAPKKKs) in the regulation of MAPK cascades, as accumulating data suggest the non-MAPKKK function of many MAPKKKs. In addition, future work on the biochemical activation of MAPK members that needs attention will be discussed.

Three dimensional confocal photoacoustic dermoscopy with an autofocusing sono-opto probe.

Photoacoustic dermoscopy (PAD) is uniquely positioned for the diagnosis and assessment of dermatological conditions because of its ability to visualize optical absorption contrast in vivo in three dimensions. In this Letter, we developed a 3D confocal PAD (3D-CPAD) equipped with an autofocusing sono-opto probe to facilitate the reconstruction of high-spatial-resolution imaging of skin with multilaminate structures in depth direction. The autofocusing sono-opto probe integrated a 10-mm electrowetting-based varifocal lens to automatically control the acoustic and optical confocal length, and an annular ultrasonic detector with a mid-frequency of ~32.8 MHz is coaxially configured for receiving photoacoustic signals. Using this sono-opto probe, the acoustic and optical confocal length-shifting range from ~7 to 43 mm with high image contrast and spatial resolution in the 3D image reconstruction. Autofocusing property tests and 3D human skin in vivo imaging were carried out to demonstrate the imaging capability of the 3D-CPAD for potential clinical foreground in noninvasive biopsies of skin disease.

Adult male-female social bond advertising: The primary function of coordinated singing intensity in a small ape.

Adult male and female coordinated singing occur in diverse animal taxa. Adult male-female social bond advertising and strengthening have been proposed as two important functional hypotheses of coordinated singing. Here we studied these two functions in four groups of cao vit gibbon (Nomascus nasutus), a small ape that lives in polygynous family groups and adult members coordinated their sex-specific songs to produce complex duets or trios (three members sing together), using 6-year field behavioral data. In this study, we used the number of successful great call sequences per bout or per minute, and latency period from start of the adult male call to the first successful great call sequence to represent singing intensity. We used the proportion of proximity, behavioral synchronization, and grooming between adult male and female to represent bond strength. We used linear mixed-effects model to investigate the correlation between singing intensity and adult male-female social bond strength. We found a negative correlation between all three bond strength indicators and female latency period (N = 209), and a positive correlation between the number of successful great call sequences per bout (N = 253) and per minute (N = 254) and proximity. We used paired Wilcoxon signed-rank test to investigate if adult gibbons increase bond strength after singing. We found proximity (hourly level: N = 45; daily level: N = 54), behavioral synchronization (hourly level: N = 57; daily level: N = 49), and grooming (daily level: N = 34) in most of the groups did not increase significantly after singing in an hourly or daily level. Together, these results indicate that cao vit gibbon coordinated singing serves primarily in adult male-female social bond advertising and distinct singing intensity indicators advertise different information on adult male-female social bond strength.

Quantitative and anatomical imaging of dermal angiopathy by noninvasive photoacoustic microscopic biopsy.

The ability to noninvasively acquire the fine structure of deep tissues is highly valuable but remains a challenge. Here, a photoacoustic microscopic biopsy (PAMB) combined switchable spatial-scale optical excitation with single-element depth-resolved acoustic detection mode was developed, which effectively coordinated the spatial resolution and the penetration depth for visualizations of skin delamination and chromophore structures up to reticular dermis depth, with the lateral resolution from 1.5 to 104 µm and the axial resolution from 34 to 57 µm. The PAMB obtained anatomical imaging of the pigment distribution within the epidermis and the vascular patterns of the deep dermal tissue, enabling quantification of morphological abnormalities of angiopathy without the need for exogenous contrast agents. The features of healthy skin and scar skin, and the abnormal alteration of dermal vasculature in port wine stains (PWS) skin were first precisely displayed by PAMB-shown multi-layered imaging. Moreover, the quantitative vascular parameters evaluation of PWS were carried out by the detailed clinical PAMB data on 174 patients, which reveals distinct differences among different skin types. PAMB captured the PWS changes in capillary-loop depth, diameter, and vascular volume, making it possible to perform an objective clinical evaluation on the severity of PWS. All the results demonstrated the PAMB can provide vascular biopsy and new indexes deep into the dermal skin noninvasively, which should be meaningful to timely evaluate the pathological types and treatment response of skin diseases. This opens up a new perspective for label-free and non-invasive biopsies of dermal angiopathy.

OsVQ1 links rice immunity and flowering via interaction with a mitogen-activated protein kinase OsMPK6.

KEY MESSAGE: Knocking out OsVQ1 in rice released OsMPK6 for activation and in turn promoted H2O2 accumulation, which repressed the expression of flowering-promoting genes, thus delaying rice flowering but enhancing disease resistance. The valine-glutamine (VQ) protein family, which contains the conserved motif FxxxVQxLTG ("x" represents any amino acid), plays a crucial role in plant growth and immunity along with mitogen-activated protein kinase (MAPK) cascades. However, only a few rice VQ proteins have been functionally characterized, and the roles of the MAPK-VQ module in rice biological processes are not fully understood. Here, we investigated the role of OsVQ1 in rice disease resistance and the control of flowering time. The OsVQ1-knock out (KO) mutants exhibited increased resistance to Xanthomonas oryzae pathovars, accumulated high levels of hydrogen peroxide (H2O2), and showed a late flowering phenotype under natural long-day conditions, while the OsVQ1-overexpressing plants showed phenotypes similar to that of the wild type. Further studies revealed that OsVQ1 physically interacted with and inhibited OsMPK6 activity. In addition, OsVQ1 expression was downregulated by the pathogen-induced OsMPKK10.2-OsMPK6-OsWRKY45 cascade, suggesting a feedback loop between OsVQ1 and OsMPK6. Moreover, the OsVQ1-KO/osmpk6 double-mutant exhibited increased susceptibility to X. oryzae infection and showed an early flowering phenotype, which may partially be attributed to the reduced accumulation of H2O2 and the consequent up-expression of flowering-promoting genes. These results suggested that the OsVQ1-OsMPK6 module was involved in rice immunity and flowering.

Two VQ Proteins are Substrates of the OsMPKK6-OsMPK4 Cascade in Rice Defense Against Bacterial Blight.

BACKGROUND: The plant-specific valine-glutamine (VQ) protein family with the conserved motif FxxxVQxLTG reportedly functions with the mitogen-activated protein kinase (MAPK) in plant immunity. However, the roles of VQ proteins in MAPK-mediated resistance to disease in rice remain largely unknown. RESULTS: In this study, two rice VQ proteins OsVQ14 and OsVQ32 were newly identified to function as the signaling components of a MAPK cascade, OsMPKK6-OsMPK4, to regulate rice resistance to Xanthomonas oryzae pv. oryzae (Xoo). Both OsVQ14 and OsVQ32 positively regulated rice resistance to Xoo. In vitro and in vivo studies revealed that OsVQ14 and OsVQ32 physically interacted with and were phosphorylated by OsMPK4. OsMPK4 was highly phosphorylated in transgenic plants overexpressing OsMPKK6, which showed enhanced resistance to Xoo. Meanwhile, phosphorylated OsVQ14 and OsVQ32 were also markedly accumulated in OsMPKK6-overexpressing transgenic plants. CONCLUSIONS: We discovered that OsVQ14 and OsVQ32 functioned as substrates of the OsMPKK6-OsMPK4 cascade to enhance rice resistance to Xoo, thereby defining a more complete signal transduction pathway for induced defenses.

Pathogen-inducible OsMPKK10.2-OsMPK6 cascade phosphorylates the Raf-like kinase OsEDR1 and inhibits its scaffold function to promote rice disease resistance.

Mitogen-activated protein kinase (MAPK) cascades regulate a myriad of plant biological processes, including disease resistance. Plant genomes encode a large number of MAPK kinase kinases (MAPKKKs) that can be divided into two subfamilies, namely MEKK-like kinases and Raf-like kinases. Thus far, the functions of MEKK-like MAPKKKs have been relatively well characterized, but the roles of Raf-like MAPKKKs in plant MAPK cascades remain less understood. Here, we report the role of OsEDR1, a Raf-like MAPKKK, in the regulation of the MAPK cascade in rice response to the bacterial pathogen Xanthomonas oryzae pv. oryzicola (Xoc). We found that OsEDR1 inhibits OsMPKK10.2 (a MAPK kinase) activity through physical interaction. Upon Xoc infection, OsMPKK10.2 is phosphorylated at S304 to activate OsMPK6 (a MAPK). Interestingly, activated OsMPK6 phosphorylates OsEDR1 at S861, which destabilizes OsEDR1 and thus releases the inhibition of OsMPKK10.2, leading to increased OsMPKK10.2 activity and enhanced resistance of rice plants to Xoc. Taken together, these results provide new insights into the functions of Raf-like kinases in the regulation of the MAPK cascade in plant immunity.

Photoacoustic and ultrasound (PAUS) dermoscope with high sensitivity and penetration depth by using a bimorph transducer.

A bimorph transducer was proposed to improve the detection sensitivity and imaging depth of photoacoustic and ultrasound (PAUS) dermoscope. By applying the bimorph transducer, the imaging depth and sensitivity of PAUS dermoscope were enhanced by simultaneously improving excitation efficiency and reception bandwidth. The integrated design of the imaging head of the dermoscope makes it highly convenient for detecting human skin. The PAUS imaging performance was demonstrated via visualizing subcutaneous tumor and depicting full structures of different skin layers from epidermis to subcutaneous tissue. The results confirm that the dermoscope with the bimorph transducer is well suited for PA and US dual-modality imaging, which can provide multi-information for skin disease.

High-speed dual-view photoacoustic imaging pen.

Today, photoacoustic imaging (PAI) is widely used to study diseases in the skin, brain, cardiovascular, and other parts. However, these studies are often carried out using physiological slices or model animals, which indicate that many PAI techniques can only be used in the laboratory. In order to promote the transformation of PAI into clinical applications or, more specifically, to extend the application of photoacoustic (PA) microscopy to areas such as the oral cavity, throat, cervix, and abdominal viscera which are difficult to detect with conventional PA microscopy systems, a PAI pen was developed. The PAI pen can be handheld and can perform forward detection and lateral detection. The imaging area is a 2.4 mm diameter circular area. In addition, it can provide a high-speed imaging mode of four frames per second and a high-resolution imaging mode of 0.25 frames per second to meet the different needs of clinical users. In this Letter, the performance of the PAI pen was tested by imaging the phantom and the human oral cavity. The experimental results prove that the PAI pen can clearly image the microvessels of the oral cavity, which indicates that it has the same imaging capability for other similar areas and has a good prospect for assisting the diagnosis of related diseases.

Wide-field monitoring and real-time local recording of microvascular networks on small animals with a dual-raster-scanned photoacoustic microscope.

Photoacoustic microscopy (PAM) provides a new method for the imaging of small-animals with high-contrast and deep-penetration. However, the established PAM systems have suffered from a limited field-of-view or imaging speed, which are difficult to both monitor wide-field activity of organ and record real-time change of local tissue. Here, we reported a dual-raster-scanned photoacoustic microscope (DRS-PAM) that integrates a two-dimensional motorized translation stage for large field-of-view imaging and a two-axis fast galvanometer scanner for real-time imaging. The DRS-PAM provides a flexible transition from wide-field monitoring the vasculature of organs to real-time imaging of local dynamics. To test the performance of DRS-PAM, clear characterization of angiogenesis and functional detail was illustrated, hemodynamic activities of vasculature in cerebral cortex of a mouse were investigated. Furthermore, response of tumor to treatment were successfully monitored during treatment. The experimental results demonstrate the DRS-PAM holds the great potential for biomedical research of basic biology.

In vivo volumetric monitoring of revascularization of traumatized skin using extended depth-of-field photoacoustic microscopy.

Faster and better wound healing is a critical medical issue. Because the repair process of wounds is closely related to revascularization, accurate early assessment and postoperative monitoring are very important for establishing an optimal treatment plan. Herein, we present an extended depth-of-field photoacoustic microscopy system (E-DOF-PAM) that can achieve a constant spatial resolution and relatively uniform excitation efficiency over a long axial range. The superior performance of the system was verified by phantom and in vivo experiments. Furthermore, the system was applied to the imaging of normal and trauma sites of volunteers, and the experimental results accurately revealed the morphological differences between the normal and traumatized skin of the epidermis and dermis. These results demonstrated that the E-DOF-PAM is a powerful tool for observing and understanding the pathophysiology of cutaneous wound healing.

Predictive Validity of Interviewer Post-interview Notes on Candidates' Job Outcomes: Evidence Using Text Data From a Leading Chinese IT Company.

Despite the popularity of the employment interview in the employee selection literature and organizational talent selection process, few have examined the comments interviewers give after each interview. This study investigated the predictability of the match between interviewer post-interview notes and radar charts from job analysis on the candidate's later career performance using text mining techniques and data from one of the largest internet-based technology companies in China. A large sample of 7,650 interview candidates who passed the interviews and joined the company was obtained to show that the number of job-related capabilities interviewers mentioned in their notes was positively related to candidate's job performance, the number of promotions, and negatively related to turnover. Moreover, the dimensions of the radar chart from job analysis covered in the interview moderated the predictability of interview post-interview notes. Our results indicated that a smaller number of radar chart dimensions by which interviewers assessed the candidates in the interview positively moderated candidates' promotion for product development jobs, and negatively moderated turnover for technical jobs. The implications of these results for structured interview research in both theory and practice are discussed.