Unsupervised deep learning enables real-time image registration of fast-scanning optical-resolution photoacoustic microscopy.

A fast scanner of optical-resolution photoacoustic microscopy is inherently vulnerable to perturbation, leading to severe image distortion and significant misalignment among multiple 2D or 3D images. Restoration and registration of these images is critical for accurately quantifying dynamic information in long-term imaging. However, traditional registration algorithms face a great challenge in computational throughput. Here, we develop an unsupervised deep learning based registration network to achieve real-time image restoration and registration. This method can correct artifacts from B-scan distortion and remove misalignment among adjacent and repetitive images in real time. Compared with conventional intensity based registration algorithms, the throughput of the developed algorithm is improved by 50 times. After training, the new deep learning method performs better than conventional feature based image registration algorithms. The results show that the proposed method can accurately restore and register the images of fast-scanning photoacoustic microscopy in real time, offering a powerful tool to extract dynamic vascular structural and functional information.

Integrated profiling identifies DXS253E as a potential prognostic marker in colorectal cancer.

BACKGROUND: Increasing evidence suggests that DXS253E is critical for cancer development and progression, but the function and potential mechanism of DXS253E in colorectal cancer (CRC) remain largely unknown. In this study, we evaluated the clinical significance and explored the underlying mechanism of DXS253E in CRC. METHODS: DXS253E expression in cancer tissues was investigated using the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The Kaplan-Meier plot was used to assess the prognosis of DXS253E. The cBioPortal, MethSurv, and Tumor Immune Estimation Resource (TIMER) databases were employed to analyze the mutation profile, methylation, and immune infiltration associated with DXS253E. The biological functions of DXS253E in CRC cells were determined by CCK-8 assay, plate cloning assay, Transwell assay, flow cytometry, lactate assay, western blot, and qRT-PCR. RESULTS: DXS253E was upregulated in CRC tissues and high DXS253E expression levels were correlated with poor survival in CRC patients. Our bioinformatics analyses showed that high DXS253E gene methylation levels were associated with the favorable prognosis of CRC patients. Furthermore, DXS253E levels were linked to the expression levels of several immunomodulatory genes and an abundance of immune cells. Mechanistically, the overexpression of DXS253E enhanced proliferation, migration, invasion, and the aerobic glycolysis of CRC cells through the AKT/mTOR pathway. CONCLUSIONS: We demonstrated that DXS253E functions as a potential role in CRC progression and may serve as an indicator of outcomes and a therapeutic target for regulating the AKT/mTOR pathway in CRC.

Structurally diverse diterpenoids and phenanthrene derivatives from the roots of Baliospermumsolanifolium.

Ten undescribed diterpenoids (1-10) and three undescribed phenanthrene derivatives (11-13), together with seven known compounds, were isolated from the roots of Baliospermum solanifolium. Their structures were determined by a combination of spectroscopic data analysis, electronic circular dichroism calculations and single-crystal X-ray diffraction studies. Compounds 1-7 (baliosperoids A-G) represent the examples of 20-nor-ent-podocarpane class first discovered in nature. In particular, compound 7 possesses a unique 2,3-seco ring system incorporating γ-butanolide moiety. All isolates were assessed for their cytotoxic activities against HT-29, HCT-116, HCT-15, MCF-7, and A549 cell lines as well as their inhibitory effects on lipopolysaccharide-induced NO production in RAW264.7 cells. Compound 1, a 20-nor-ent-podocarpane-type diterpenoid possessing a Δ1,2 double bond, not only exhibited considerable proliferation inhibition against five human cancer cell lines, with IC50 values ranging from 4.13 to 23.45 µM, but also displayed the most potent inhibitory activity on NO production with IC50 value at the nanomolar level (0.63 ± 0.21 µM).

Fractal Design of Hierarchical PtPd with Enhanced Exposed Surface Atoms for Highly Catalytic Activity and Stability.

Hierarchical assembly of arc-like fractal nanostructures not only has its unique self-similarity feature for stability enhancement but also possesses the structural advantages of highly exposed surface-active sites for activity enhancement, remaining a great challenge for high-performance metallic nanocatalyst design. Herein, we report a facile strategy to synthesize a novel arc-like hierarchical fractal structure of PtPd bimetallic nanoparticles (h-PtPd) by using pyridinium-type ionic liquids as the structure-directing agent. Growth mechanisms of the arc-like nanostructured PtPd nanoparticles have been fully studied, and precise control of the particle sizes and pore sizes has been achieved. Due to the structural features, such as size control by self-similarity growth of subunits, structural stability by nanofusion of subunits, and increased numbers of exposed active atoms by the curved homoepitaxial growth, h-PtPd displays outstanding electrocatalytic activity toward oxygen reduction reaction and excellent stability during hydrothermal treatment and catalytic process.

WFDC3 inhibits tumor metastasis by promoting the ERß-mediated transcriptional repression of TGFBR1 in colorectal cancer.

Estrogen plays a protective role in colorectal cancer (CRC) and primarily functions through estrogen receptor ß (ERß). However, clinical strategies for CRC therapy associated with ERß are still under investigation. Our discoveries identified WFDC3 as a tumor suppressor that facilitates estrogen-induced inhibition of metastasis through the ERß/TGFBR1 signaling axis. WFDC3 interacts with ERß and increases its protein stability by inhibiting its proteasome-dependent degradation. WFDC3 represses TGFBR1 expression through ERß-mediated transcription. Blocking TGFß signaling with galunisertib, a drug used in clinical trials that targets TGFBR1, impaired the migration of CRC cells induced by WFDC3 depletion. Moreover, there was clinical significance to WFDC3 in CRC, as CRC patients with high WFDC3 expression in tumor cells had favorable prognoses. Therefore, this work suggests that WFDC3 could be an indicator for therapies targeting the estrogen/ERß pathway in CRC patients.

Application of transmesenteric vein extrahepatic portosystemic shunt in treatment of symptomatic portal hypertension with cavernous transformation of portal vein.

Purpose: To evaluate the feasibility and efficacy of a transmesenteric vein extrahepatic portosystemic shunt (TmEPS) for the treatment of cavernous transformation of the portal vein (CTPV). Materials and methods: The clinical data of 20 patients with CTPV who underwent TmEPS between December 2020 and January 2022 â€‹at Henan Provincial People's Hospital were retrospectively collected. The superior mesenteric vein (SMV) trunk was patent or partially occluded in these patients. An extrahepatic portosystemic shunt between the inferior vena cava and the SMV was established using a stent graft through an infraumbilical median longitudinal mini-laparotomy. The technical success, efficacy, and complication rates were evaluated, and the pre- and postoperative SMV pressures were compared. Patients' clinical outcomes and shunt patency were assessed. Results: TmEPS was successfully performed in 20 patients. The initial puncture success rate of the balloon-assisted puncture technique is 95%. The mean SMV pressure decreased from 29.1 â€‹± â€‹2.9 â€‹mmHg to 15.6 â€‹± â€‹3.3 â€‹mmHg (p â€‹< â€‹0.001). All symptoms of portal hypertension resolved. No fatal procedural complications occurred. During the follow-up period, hepatic encephalopathy occurred in two patients. The remaining patients remained asymptomatic. All shunts were patent. Conclusions: TmEPS is a feasible, safe, and effective treatment option for patients with CTPV.

Super-Low-Dose Functional and Molecular Photoacoustic Microscopy.

Photoacoustic microscopy can image many biological molecules and nano-agents in vivo via low-scattering ultrasonic sensing. Insufficient sensitivity is a long-standing obstacle for imaging low-absorbing chromophores with less photobleaching or toxicity, reduced perturbation to delicate organs, and more choices of low-power lasers. Here, the photoacoustic probe design is collaboratively optimized and a spectral-spatial filter is implemented. A multi-spectral super-low-dose photoacoustic microscopy (SLD-PAM) is presented that improves the sensitivity by ≈33 times. SLD-PAM can visualize microvessels and quantify oxygen saturation in vivo with ≈1% of the maximum permissible exposure, dramatically reducing potential phototoxicity or perturbation to normal tissue function, especially in imaging of delicate tissues, such as the eye and the brain. Capitalizing on the high sensitivity, direct imaging of deoxyhemoglobin concentration is achieved without spectral unmixing, avoiding wavelength-dependent errors and computational noises. With reduced laser power, SLD-PAM can reduce photobleaching by ≈85%. It is also demonstrated that SLD-PAM achieves similar molecular imaging quality using 80% fewer contrast agents. Therefore, SLD-PAM enables the use of a broader range of low-absorbing nano-agents, small molecules, and genetically encoded biomarkers, as well as more types of low-power light sources in wide spectra. It is believed that SLD-PAM offers a powerful tool for anatomical, functional, and molecular imaging.

Simultaneous dual-modal photoacoustic and harmonic ultrasound microscopy with an optimized acoustic combiner.

Simultaneous photoacoustic (PA) and ultrasound (US) imaging provides rich optical and acoustic contrasts with high sensitivity, specificity, and resolution, making it a promising tool for diagnosing and assessing various diseases. However, the resolution and penetration depth tend to be contradictory due to the increased attenuation of high-frequency ultrasound. To address this issue, we present simultaneous dual-modal PA/US microscopy with an optimized acoustic combiner that can maintain high resolution while improving the penetration of ultrasound imaging. A low-frequency ultrasound transducer is used for acoustic transmission, and a high-frequency transducer is used for PA and US detection. An acoustic beam combiner is utilized to merge the transmitting and receiving acoustic beams with a predetermined ratio. By combining the two different transducers, harmonic US imaging and high-frequency photoacoustic microscopy are implemented. In vivo experiments on the mouse brain demonstrate the simultaneous PA and US imaging ability. The harmonic US imaging of the mouse eye reveals finer iris and lens boundary structures than conventional US imaging, providing a high-resolution anatomical reference for co-registered PA imaging.

Elevating the d-Band Center of Ni3S2 Nanosheets by Fe Incorporation to Boost the Oxygen Evolution Reaction.

Many attempts have been made to enhance the relatively poor electrochemical activity of Ni3S2 for the oxygen evolution reaction (OER) by elevating the d-band center. Unfortunately, only limited success has been encountered thus far. Owning to the lower electronegativity and one less 3d electron relative to Ni, Fe shows great potentials in upshifting the overall d-band center of Ni3S2 when incorporating into its crystal structures. Herein, to enhance the intrinsic activity by elevating the d-band center, Ni3S2 nanosheets incorporated with suitable Fe content have been fabricated by a facile one-step solvothermal method. The obtained Fe-incorporated Ni3S2 catalyst exhibits an outstanding OER performance in alkaline media, only requiring 244 mV overpotential (with a reduction of 210 mV compared to Ni3S2) at 50 mA cm-2 in 1 M KOH and without obvious degradation after sustaining for a 60 h test at a voltage above 1.5 V. Ultraviolet photoemission spectroscopy and density functional theory calculations consistently demonstrate that the superior performance of Fe-incorporated Ni3S2 is attributed to the upshift of the d-band center on neutralizing the electron densities of Ni, which optimize greatly the adsorption energy of the intermediate (OOH*) in the rate-determining Volmer step.

Genome-wide transcriptomics and copy number profiling identify patient-specific CNV-lncRNA-mRNA regulatory triplets in colorectal cancer.

Screening cancer genomes has provided an in-depth characterization of genetic variants such as copy number variations (CNVs) and gene expression changes of non-coding transcripts. Single-dimensional experiments are often designed to differentiate a patient cohort into various sets with the aim of identifying molecular changes among groups; however, this may be inadequate to decipher the causal relationship between molecular signatures in individual patients. To overcome this challenge with respect to personalized medicine, we implemented a patient-specific multi-dimensional integrative approach to uncover coherent signals from multiple independent platforms. In particular, we focused on the consistent gene dosage effects of CNVs for both mRNA and long non-coding RNA (lncRNA) expression in nine colorectal cancer patients. We identified 511 CNV-lncRNA-mRNA regulatory triplets associated with CNVs and aberrant expression of both mRNAs and lncRNAs. By filtering out inconsistent changes among CNVs, mRNAs, and lncRNAs, we further characterized 165 coherent motifs associated with 56 genes. In total, 108 motifs were linked with 31 copy number gains, 44 upregulated lncRNAs, and 45 upregulated mRNAs. Another 57 coherent downregulated motifs were also collected. We discuss how for many of these CNV-lncRNA-mRNA regulatory triplets, their clinical impact remains to be explored, including survival time, microsatellite instability, tumor stage, and primary tumor sites. By validating two example CNV-lncRNA-mRNA triplets with up- and down-regulation, we confirmed that individual variations in multiple dimensions are a robust tool to identify reliable molecular signals for personalized medicine. In summary, we utilized a patient-specific computational pipeline to explore the consistent CNV-driven motifs consisting of lncRNAs and mRNAs. We also identified LSM14B as a potential promoter in colorectal cancer progression, suggesting that it may serve as a target for colorectal cancer treatment.

A RuCoBO Nanocomposite for Highly Efficient and Stable Electrocatalytic Seawater Splitting.

Efficient and stable electrocatalysts are critically needed for the development of practical overall seawater splitting. The nanocomposite of RuCoBO has been rationally engineered to be an electrocatalyst that fits these criteria. The study has shown that a calcinated RuCoBO-based nanocomposite (Ru2Co1BO-350) exhibits an extremely high catalytic activity for H2 and O2 production in alkaline seawater (overpotentials of 14 mV for H2 evolution and 219 mV for O2 evolution) as well as a record low cell voltage (1.466 V@10 mA cm-2) and long-term stability (230 h @50 mA cm-2 and @100 mA cm-2) for seawater splitting. The results show that surface reconstruction of Ru2Co1BO-350 occurs during hydrogen evolution reaction and oxygen evolution reaction, which leads to the high activity and stability of the catalyst. The reconstructed surface is highly resistant to Cl- corrosion. The investigation suggests that a new strategy exists for the design of high-performance Ru-based electrocatalysts that resist anodic corrosion during seawater splitting.

AhR regulates VEGF expression by promoting STAT1 transcriptional activity, thereby affecting endothelial angiogenesis in acute limb ischemia.

BACKGROUND: Angiogenesis has great potential in the treatment of acute limb ischemia (ALI). Here, we aimed to investigate the effect and mechanism of Aryl hydrocarbon receptor (AhR) on angiogenesis in ALI. METHODS: The ALI mouse model was constructed by femoral artery ligation, and the cell ischemia injury was induced by Hypoxia/serum deprivation. The laser doppler perfusion imaging was executed to detect the limb blood flow velocity. The tube formation assay was performed to evaluate angiogenesis. The cell viability was measured by 3-(45)-dimethylthiahiazo(-z-y1)-35-di-phenytetrazoliumromide. The cell migration was detected by wound healing assay. Hematoxylin-eosin, immunohistochemistry, immunofluorescence, dual-luciferase reporter gene assay, and Chromatin immunoprecipitation assay were conducted. RESULTS: In ALI models, AhR expression was increased and translocated from cytoplasm to nucleus. Besides, necrosis and inflammatory infiltration were also increased in gastrocnemius tissues of model mice. In addition, AhR loss (LV-sh-AhR) promoted cell viability, angiogenesis, and migration, and also elevated the levels of vascular endothelial growth factor (VEGF), Tie2, and Ang2 in HUVEC models with Hypoxia/serum deprivation injury. Meanwhile, the interaction between AhR and signal transducer and activator of transcription 1 (STAT1), as well as STAT1 and VEGF, has also been confirmed. Co-transfection of LV-sh-AhR and LV-STAT1 suppressed cell viability, angiogenesis, and migration of injured HUVECs. Furthermore, injection of AAV2/9-shAhR in vivo also promoted angiogenesis, which was consistent with the in vitro experimental results. CONCLUSIONS: In ALI models, activated AhR was translocated to the nucleus and down-regulated VEGF expression by promoting the transcriptional activity of STAT1, thereby inhibiting endothelial angiogenesis.

Complete Endovascular Reconstruction of the Canine Ascending Aorta, Aortic Arch, and Supra-Aortic Vessels by Implanting a New Unibody Outer Double-Branched Stent-Graft.

PURPOSE: We evaluated the feasibility and safety of using a new unibody outer double-branched stent-graft system to reconstruct the canine ascending aorta, aortic arch, and supra-aortic vessels. MATERIALS AND METHODS: The outer-branched stent-graft was a unibody design. The branched stent-graft consisted of a main stent-graft and 2 branches. The introducer system included a tri-channel catheter, 2 detachable sleeves, a front fixing device, a constraining wire, and a curved outer sheath. The branched stent-graft was loaded into the introducer system. Ten adult mongrel dogs underwent general anesthesia, and the branched stent-grafts were deployed into the canine ascending aorta, aortic arch, and supra-aortic vessels by the introducer system. All animals were followed up for 3 months. At the end of the follow-up period, computed tomographic angiography (CTA) was performed to observe the patency of the branched stent-grafts. RESULTS: The mean operation time was 142.7±13.7 minutes. The mean fluoroscopy time was 20.73±2.22 minutes. The mean dosage of contrast agent was 95.9±8.7 mL. During the operation, the tri-channel catheters successfully paralleled the wires in the aorta. All 10 branched stent-grafts were successfully implanted into the canine ascending aorta and aortic arch. There were no symptoms of cerebral embolization and no incision infection during the follow-up period. Computed tomographic angiography and specimens showed that the branched stent-grafts and native vessels were patent, the inner surfaces of the branched stent-grafts were covered by neointima, and there was no retrograde aortic dissection in the ascending aorta. CONCLUSIONS: This animal research demonstrated that the unibody outer double-branched stent-graft system could be applied to reconstruct the canine ascending aorta, aortic arch, and supra-aortic vessels. CLINICAL IMPACT: Thoracic endovascular aortic repair has been the main treatment method for aortic aneurysms or dissections involving the descending thoracic aorta. However, the aortic arch and ascending aorta remain the last segments of the aorta without a validated and routinely used endovascular option. In this research, we designed a new unibody outer branched stent-graft system to reconstruct the distal ascending aorta, aortic arch and supra-aortic vessels. The unibody outer branched stent-graft system could be applied to treat aortic pathologies which involve the middle and distal proximal ascending aorta, aortic arch and proximal descending aorta.

Whole genome re-sequencing reveals artificial and natural selection for milk traits in East Friesian sheep.

The East Friesian sheep is one of the important high-yielding dairy sheep breeds, but still little is known about their genetic and genomic variation during domestication. Therefore, we analyzed the genomic data of 46 sheep with the aim of identifying candidate genes that are closely related to milk production traits. Our genomic data consisted of 20 East Friesian sheep and 26 Asian Mouflon wild sheep. Finally, a total of 32590241 SNPs were identified, of which 0.61% (198277) SNPs were located in exonic regions. After further screening, 122 shared genomic regions in the top 1% of F ST and top 1% of Nucleotide diversity ratio were obtained. After genome annotation, these 122 candidate genomic regions were found to contain a total of 184 candidate genes. Finally, the results of KEGG enrichment analysis showed four significantly enriched pathways (P < 0.05): beta-Alanine metabolism (SMOX, HIBCH), Pathways in cancer (GLI2, AR, TXNRD3, TRAF3, FGF16), Non-homologous end-joining (MRE11), Epstein-Barr virus infection (TRAF3, PSMD13, SIN3A). Finally, we identified four important KEGG enrichment pathways and 10 candidate genes that are closely related to milk production in East Friesian sheep. These results provide valuable candidate genes for the study of milk production traits in East Friesian sheep and lay an important foundation for the study of milk production traits.

A canine model of aortic arch aneurysm created with autologous pericardium.

Background: To establish a canine model of aortic arch aneurysm that is suitable for research on new devices and techniques applied to the aortic arch. Materials and methods: Fifteen mongrel dogs underwent surgery. The autologous pericardial patch was sewn on the aortotomy site in the anterior wall of the aortic arch. The animals were followed up for 3 months postoperatively. Computed tomography angiography was used to visualize and measure the aneurysm model. Hematoxylin and eosin staining was used to observe the histological characteristics of the aneurysm model. Changes in aneurysm diameter over time were analyzed using analysis of variance. Results: One dog died of hemorrhage during surgery. Fourteen dogs survived the surgical procedure. Two of them died on the first postoperative day because of ruptures at the suturing margin. The diameter of the aneurysm model was twice as large as that of the aortic arch. There was no significant change in the maximum diameter of the aneurysm model during the follow-up period. Conclusions: We established a controllable and stable aortic arch aneurysm model created with an autologous pericardium patch. The aneurysm model can be used to research endoleaks after thoracic endovascular aortic repair and new endovascular techniques can be applied to the aortic arch.

Freehand scanning photoacoustic microscopy with simultaneous localization and mapping.

Optical-resolution photoacoustic microscopy offers high-resolution, label-free hemodynamic and functional imaging to many biomedical applications. However, long-standing technical barriers, such as limited field of view, bulky scanning probes, and slow imaging speed, have limited the application of optical-resolution photoacoustic microscopy. Here, we present freehand scanning photoacoustic microscopy (FS-PAM) that can flexibly image various anatomical sites. We develop a compact handheld photoacoustic probe to acquire 3D images with high speed, and great flexibility. The high scanning speed not only enables video camera mode imaging but also allows for the first implementation of simultaneous localization and mapping (SLAM) in photoacoustic microscopy. We demonstrate fast in vivo imaging of some mouse organs, and human oral mucosa. The high imaging speed greatly reduces motion artifacts and distortions from tissue moving, breathing, and unintended handshaking. We demonstrate small-lesion localization in a large region of the brain. FS-PAM offers a flexible high-speed imaging tool with an extendable field of view, enabling more biomedical imaging applications.

Interfacial Carbon Makes Nano-Particulate RuO2 an Efficient, Stable, pH-Universal Catalyst for Splitting of Seawater.

An electrocatalyst composed of RuO2 surrounded by interfacial carbon, is synthesized through controllable oxidization-calcination. This electrocatalyst provides efficient charge transfer, numerous active sites, and promising activity for pH-universal electrocatalytic overall seawater splitting. An electrolyzer with this catalyst gives current densities of 10 mA cm-2 at a record low cell voltage of 1.52 V, and shows excellent durability at current densities of 10 mA cm-2 for up to 100 h. Based on the results, a mechanism for the catalytic activity of the composite is proposed. Finally, a solar-driven system is assembled and used for overall seawater splitting, showing 95% Faraday efficiency.

Targeted Multifunctional Nanoplatform for Imaging-Guided Precision Diagnosis and Photothermal/Photodynamic Therapy of Orthotopic Hepatocellular Carcinoma.

Background: Effective theranostic of hepatocellular carcinoma (HCC) in an early-stage is imminently demanded to improve its poor prognosis. Combination of the near-infrared (NIR) photoacoustic imaging (PAI) and fluorescence imaging (FLI) can provide high temporospatial resolution, outstanding optical contrast, and deep penetration and thus is promising for accurate and sensitive HCC diagnosis. Methods: A versatile CXCR4-targeted Indocyanine green (ICG)/Platinum (Pt)-doped polydopamine melanin-mimic nanoparticle (designated ICG/Pt@PDA-CXCR4, referred to as IPP-c) is synthesized as an HCC-specific contrast agent for high-resolution precise diagnostic PAI/FLI and optical imaging-guided targeted photothermal therapy (PTT)/photodynamic therapy (PDT) of orthotopic small hepatocellular carcinoma (SHCC). Results: The multifunctional targeted nanoparticle yields superior HCC specificity, high imaging contrast in both PAI and FLI, good stability, reliable biocompatibility, effective singlet oxygen generation and superior photothermal conversion efficiency (PCE, 58.7%) upon 808-nm laser irradiation. The targeting ability of IPP-c was validated in in vitro experiments on selectively killing the CXCR4-overexpressing HCC cells. Moreover, we test the efficient dual-modal optical precision diagnosis properties of IPP-c via in vivo experiments on targeted particle accumulation in an early-stage SHCC mouse model (tumor diameter about 1.2 mm). Then, under the guidance of real-time optical imaging, effective and mini-invasive PTT/PDT of orthotopic SHCCs were demonstrated without damaging adjacent liver tissues or other major organs. Conclusion: This study presented a multifunctional CXCR4-targeted nanoparticle to conduct effective and mini-invasive phototherapeutics of orthotopic SHCCs via the real-time quantitative guidance by optical imaging, which provided a new perception for building a versatile targeted nanoplatform for phototheranostics of early-stage HCC.

A spatial homojunction of titanium vacancies decorated with oxygen vacancies in TiO2 and its directed charge transfer.

The n-p homojunction design in semiconductors could enable directed charge transfer, which is promising but rarely reported. Herein, TiO2 with a spatial n-p homojunction has been designed by decorating TiO2 nanosheets with Ti vacancies around nanostructured TiO2 with O vacancies. 2D 1H TQ-SQ MAS NMR, EPR and XPS show the junction of titanium vacancies and oxygen vacancies at the interface. This spatial homojunction contributes to a significant enhancement in photoelectrochemical and photocatalytic performance, especially photocatalytic seawater splitting. Density functional theory calculations of the charge density reveal the directional n-p charge transfer path at the interface, which is proposed at the atomic-/nanoscale to clarify the generation of rational junctions. The spatial n-p homojunction provides a facile strategy for the design of high-performance semiconductors.

Multi-focus image fusion with enhancement filtering for robust vascular quantification using photoacoustic microscopy.

Accurate identification and quantification of microvascular patterns are important for clinical diagnosis and therapeutic monitoring using optical-resolution photoacoustic microscopy (OR-PAM). Due to its limited depth of field, conventional OR-PAM may not fully reveal microvascular patterns with enough details in depth range, which affects the segmentation and quantification. Here, we propose a robust vascular quantification approach via combining multi-focus image fusion with enhancement filtering (MIFEF). The multi-focus image fusion is constructed based on multi-scale gradients and image matting to improve image fusion quality by considerably achieving accurate focus measurement for initial segmentation as well as decision map refinement. The enhancement filtering identifies the vessels and handles noise without deforming microvasculature. The performance of the MIFEF were evaluated employing a leaf phantom, mouse livers and brains. The proposed method for OR-PAM can significantly facilitate the clinical provision of optical biopsy of vascular-related diseases.