Limited Depth Research Articles

Investigation of the X‐ray fluorescence technique in the characterization of Ni coatings applied to historical heritage studies

AbstractHistorical heritage pieces allow a better comprehension of the characteristics of different civilizations over time. The characterization of such pieces is of paramount importance for their preservation. Energy‐dispersive X‐ray fluorescence (EDXRF) is recommended for this application, mostly because it is non‐destructive and the equipment is portable. However, one of its limitations is the difficulty in separating the signal from the substrate and the coating of multilayered samples, as it does not provide depth resolution. This project investigates the application of EDXRF in the characterization of metallic coatings, in the context of historical heritage. The elemental concentration of electrodeposited Ni coatings onto carbon steel substrates was obtained from EDXRF analyses. The relationship between the layer thickness and the variation of the Kα/Kβ intensity ratio of nickel peaks was exploited and the thicknesses of the coatings were estimated through EDXRF measurements. For comparison, particle‐induced x‐ray emission spectroscopy and scanning electron microscopy of the cross‐section were employed, providing a depth profile of the coatings. The estimated thicknesses from EDXRF analysis were comparable to those observed in the microscopy images for thinner films (up to 8 μm). On the other hand, for thicker films, the thicknesses were underestimated, due to the technique's depth limit and matrix effects, as secondary absorption. Despite these limitations, EDXRF remains valuable for evaluating cultural heritage pieces, often providing sufficient information to address authenticity concerns or to guide restoration processes. A case study was also performed to apply the methodology discussed on historical metallic pieces.

Two-photon NIR-responsive carbon dots incorporated into NMOFs for targeted photodynamic therapy

In recent years, Photodynamic therapy (PDT) has shown great potential in clinics to treat cancer. Due to the limited depth range of UV or visible laser light penetration, the eradication of solid tumors using traditional photosensitizer is difficult. Here, we report the development of a new NIR active photosensitizer covalently conjugated to nanoscale metal-organic frameworks (NMOFs) for the eradication of deep-seated tumors. This photosensitizer can generate reactive oxygen species (ROS) in the presence of near-infrared light irradiation (980 nm) for PDT. Therefore, we use a strategy to develop two-photon absorbing carbon dots with a fluorescence quantum yield of 13%. The NMOFs are fabricated in the presence of folic acid, which enables them to target cancer cells that overexpress the folate receptor. NMOFs are used as a nanocarrier for CDs and are employed to achieve targeted PDT. This study is the first to observe that carbon dots embedded in NMOF composite could generate singlet oxygen (1O2) under the 980 nm laser light irradiation and also specifically target cancer cells. At a concentration of 100 μg/ml, the nanocomposite demonstrated a 73% rate of cell inhibition. The primary results reported here will show great potential in the future to develop multifunctional carbon dots for targeted two-photon PDT in the presence of higher wavelength light irradiation.

Implementation of a novel EOR screening methodology to the oilfields in Türkiye

In response to growing energy demand of Türkiye, an enhanced oil recovery (EOR) applicability assessment was conducted through an improved screening methodology, calibrated with successful applications. The methodology incorporated some improvements in applicability ranges and a novel pointing system. 159 oilfields in Türkiye were characterized based on reservoir properties and categorized as heavy, weak and strong aquifer support. The characterization revealed how source rock type and regional paleo-tectonic events dictate primary recovery and need for EOR. The EOR assessment implemented promised 58 applicable cases out of 315. Carbon dioxide (CO2) injection is applicable for many fields, which could stimulate feasibility of carbon capture projects in the country. Immiscible nitrogen injection might be an alternative for many of the medium and light oil reservoirs in the absence of CO2. Polymer flooding is also promising mainly for fields having weak-aquifer support. However, our hands-on experience suggests that conformance control is required to control flow of EOR agent in densely fractured carbonates. Thermal methods do not seem applicable in heavy oil reservoirs due to depth limitations except in-situ combustion, which requires pilot test confirmation. Provided methodology in this study may be used as a guideline for other fields to assess EOR potential.

Response of late-sown wheat (Triticum aestivum) to limited irrigation, seed rate and depth of sowing

A field experiment was conducted during the winter (rabi) season of 2014–15 and 2015–16 at New Delhi, to study the effect of limited irrigation, seed rate and depth of sowing on growth, yield, water-use parameters and economics of late-sown wheat (Triticum aestivum L.). The experiment comprised 3 factors, viz. 3 irrigation levels [(I1 , irrigation at crown-root initation (CRI) stage; I2 , irrigation at CRI stage + 0.2 irrigation water: cumulative pan evaporation (IW : CPE) ratio; and I3, irrigation at CRI stage + 0.4 IW : CPE ratio), 3 seed rates (S1, 75; S2, 100 and S2, 125 kg/ha) and 2 depths of sowings (D1, 5 cm and D2 , 10 cm). The field experiment comprising 18 treatment combinations, replicated thrice, was laid out in strip-plot design. Interactions between irrigation levels and seed rates, and irrigation levels and depths of sowing for grain yield were significant during 2014–15. Irrigation levels, seed rates and depths of sowing also significantly affected plant height, yield attributes, grain yield, straw yield and harvest index. Irrigation at CRI stage + 0.4 IW : CPE ratio resulted in significantly the highest plant height (86.3 cm), effective tillers/m2 (407.82), spike length (14.40 cm), spikelets/spike (17.43), grains/spike (44.20), grain weight/spike (2.05 g), 1,000-grain weight (48.95 g), grain yield (4.22 and 3.75 t/ha during 2014–15 and 2015–16) and harvest index (0.497 and 0.477 during respective season). Seed rate of 125 kg/ha resulted in significantly the highest plant height (82.7 cm), effective tillers/m2 (416.66), spike length (14.62 cm), spikelets/spike (17.53), grains/ spike (40.20), grain weight/spike (2.06 g), 1,000-grain weight (47.80 g), grain yield (3.63 t/ha during 2015–16) and harvest index (0.496 and 0.456 during respective year). Sowing depth of 10 cm resulted in significantly the highest plant height (82.2 cm), effective tillers/m2 (382.64), spike length (13.94 cm), spikelets/spike (16.44), grains/spike (38.21), grain weight/spike (1.90 g), 1,000-grain weight (46.24 g), grain yield (3.95 and 3.49 t/ha during both the years) and harvest index (0.456 and 0.443 during both the years).

Ultrasmall copper-based nanoplatforms for NIR-II light-triggered photothermal/ photodynamic and amplified nanozyme catalytic therapy of hypoxic tumor

The clinical applications of the photothermal therapy (PTT) and photodynamic therapy (PDT) are restricted by the limited tissue penetration depth of excitation light, while the enzyme catalysis therapy is hindered on account of the low treatment efficiency. Herein, we modify artificial nanozyme Pt nanoparticles on the surface of CuCo2S4 nanoparticles to prepare ultrasmall copper-based ternary bimetallic chalcogenides CuCo2S4-Pt-PEG nanocomposites for PTT/PDT/enzyme catalysis synergistic therapy. The as-fabricated CuCo2S4-Pt-PEG nanocomposites display peroxidase (POD)-like and catalase (CAT)-like activities, which can catalyze hydrogen peroxide to emerge highly toxic hydroxyl radicals and oxygen, respectively. The integration of Pt nanozyme significantly improves the POD-like and CAT-like activity of CuCo2S4 −PEG that can produce more hydroxyl radicals and oxygen to improve the effects of PDT. Furthermore, the nanocomposites exhibit outstanding photothermal properties derived from the enhanced photothermal conversion efficiency (η = 78.46 %) exposed to 1064 nm NIR-II light irradiation with a low power density (0.8 W cm−2). In particular, the photothermal performance of CuCo2S4-Pt-PEG significantly enhances the enzyme-like activity. Additionally, the T1-weighted magnetic resonance and photoacoustic imaging endow CuCo2S4-Pt-PEG with the advantages of guiding the treatment process. The synergistic treatment demonstrates significant anticancer treatment efficiency while also elicits immune response that suppressed metastasis. This study could further promote the application of ternary bimetallic chalcogenides in cancer diagnosis and treatment.

Photoimmunotheranostics of epithelioid sarcoma by targeting CD44 or EGFR

Epithelioid sarcoma (ES) is a rare soft tissue neoplasm with high recurrence rates. Wide surgical resection remains the only potential curative treatment. ES presents most commonly on the fingers, hands and forearm, making light-based cancer cell-targeted therapies such as near-infrared photoimmunotherapy (NIR-PIT) that is target-specific, but with limited penetration depth, suitable for ES treatment. We established that CD44 and EGFR were overexpressed in ES patient samples and in the VA-ES-BJ human ES cell line. NIR-PIT of VA-ES-BJ cells using antibody photosensitizer conjugates, prepared by conjugating a CD44 or EGFR monoclonal antibody to the photosensitizer IR700, confirmed that NIR-PIT with both conjugates resulted in cell death. Neither treatment with NIR light alone nor treatment with the conjugates but without NIR light were effective. CD44-IR700-PIT resulted in greater cell death than EGFR-IR700-PIT, consistent with the increased expression of CD44 by VA-ES-BJ cells. In tumors, EGFR-IR700 exhibited a higher tumor-to-normal ratio, as determined by in vivo fluorescence imaging, and a higher anti-tumor growth effect, compared to CD44-IR700. No antitumor effect of the EGFR antibody or the photosensitizer conjugate alone was observed in vivo. Our data support evaluating the use of EGFR-IR700-PIT in the management of ES for detecting and eliminating ES cells in surgical margins, and in the treatment of superficial recurrent tumors.

Open-Top Patterned Hydrogel-Laden 3D Glioma Cell Cultures for Creation of Dynamic Chemotactic Gradients to Direct Cell Migration.

The laminar flow profiles in microfluidic systems coupled to rapid diffusion at flow streamlines have been widely utilized to create well-controlled chemical gradients in cell cultures for spatially directing cell migration. However, within hydrogel-based closed microfluidic systems of limited depth (≤0.1 mm), the biomechanical cues for the cell culture are dominated by cell interactions with channel surfaces rather than with the hydrogel microenvironment. Also, leaching of poly(dimethylsiloxane) (PDMS) constituents in closed systems and the adsorption of small molecules to PDMS alter chemotactic profiles. To address these limitations, we present the patterning and integration of a PDMS-free open fluidic system, wherein the cell-laden hydrogel directly adjoins longitudinal channels that are designed to create chemotactic gradients across the 3D culture width, while maintaining uniformity across its ∼1 mm depth to enhance cell-biomaterial interactions. This hydrogel-based open fluidic system is assessed for its ability to direct migration of U87 glioma cells using a hybrid hydrogel that includes hyaluronic acid (HA) to mimic the brain tumor microenvironment and gelatin methacrylate (GelMA) to offer the adhesion motifs for promoting cell migration. Chemotactic gradients to induce cell migration across the hydrogel width are assessed using the chemokine CXCL12, and its inhibition by AMD3100 is validated. This open-top hydrogel-based fluidic system to deliver chemoattractant cues over square-centimeter-scale areas and millimeter-scale depths can potentially serve as a robust screening platform to assess emerging glioma models and chemotherapeutic agents to eradicate them.

X-ray-activated polymerization expanding the frontiers of deep-tissue hydrogel formation

Photo-crosslinking polymerization stands as a fundamental pillar in the domains of chemistry, biology, and medicine. Yet, prevailing strategies heavily rely on ultraviolet/visible (UV/Vis) light to elicit in situ crosslinking. The inherent perils associated with UV radiation, namely the potential for DNA damage, coupled with the limited depth of tissue penetration exhibited by UV/Vis light, severely restrict the scope of photo-crosslinking within living organisms. Although near-infrared light has been explored as an external excitation source, enabling partial mitigation of these constraints, its penetration depth remains insufficient, particularly within bone tissues. In this study, we introduce an approach employing X-ray activation for deep-tissue hydrogel formation, surpassing all previous boundaries. Our approach harnesses a low-dose X-ray-activated persistent luminescent phosphor, triggering on demand in situ photo-crosslinking reactions and enabling the formation of hydrogels in male rats. A breakthrough of our method lies in its capability to penetrate deep even within thick bovine bone, demonstrating unmatched potential for bone penetration. By extending the reach of hydrogel formation within such formidable depths, our study represents an advancement in the field. This application of X-ray-activated polymerization enables precise and safe deep-tissue photo-crosslinking hydrogel formation, with profound implications for a multitude of disciplines.

Molecular diversity of black corals from the Saudi Arabian Red Sea: a first assessment.

Black corals occur as part of benthic assemblages from shallow to deep waters in all oceans. Despite the importance in many benthic ecosystems, where these act as biodiversity aggregators, antipatharians remain poorly studied, with 75% of the known species occurring below recreational SCUBA diving depth limits. Currently, information regarding the diversity and evolutionary history is limited, with most studies focusing on Hawaii and the South Pacific Ocean. Other regions of the world have received less attention, such as the Red Sea, where only two black coral families and four genera have been recorded. We provide the first analysis of the molecular diversity of black corals in the eastern Gulf of Aqaba and the northern and central Saudi Arabian Red Sea, based on a dataset of 161 antipatharian colonies collected down to 627 m deep. Based on specimen morphology, we ascribed our material to 11 genera belonging to 4 of the 7 known Antipatharia families, i.e. Antipathidae, Aphanipathidae, Myriopathidae and Schizopathidae. The genus level phylogeny of three intergenic mitochondrial regions, the trnW-IGR-nad2 (IgrW ), nad5-IGR-nad1 (IgrN ) and cox3-IGR-cox1 was reconstructed including previously published material. Overall, we recovered six molecular clades that included exclusively Red Sea sequences, with the highest diversity occurring at mesophotic depths. This study highlights that diversity of black corals in the Red Sea is much higher than previously known, with seven new generic records, suggesting that this basin may be a hotspot for antipatharian diversity as is known for other taxa. Our results recovered unresolved relationships within the order at the familial and generic levels. This emphasises the urgent need for an integration of genomic-wide data with a re-examination of informative morphological features necessary to revise the systematics of the order at all taxonomic levels.

PEMETAAN KERAWANAN BANJIR DI KOTA SURAKARTA

<p class="Keywords"><em><span lang="EN-GB">Floods have become one of the problems occurring in the city of Surakarta. The floods are caused by the overflow of the tributaries of the Bengawan Solo River, located within the Surakarta City area. One of the strategies for flood disaster management is through flood zone mapping. In flood vulnerability mapping, hydrological analysis is conducted to determine the magnitude of the flood discharge for different return periods (Q<sub>2</sub>, Q<sub>5</sub>, Q<sub>10</sub>, Q<sub>25</sub>, and Q<sub>50</sub>) using the HSS SCS method, which will serve as input for the HEC-RAS program to simulate floods, used as determining variables in flood vulnerability mapping. The results of the flood simulation analysis indicate that the level of vulnerability in non-vulnerable areas has a flood area limit ranging from 1.05 ha to 8.93 ha, a maximum flood depth limit ranging from 0.24 m to 0.57 m, and a maximum flood velocity limit ranging from 0.06 m/sec to 0.21 m/sec. For areas with low vulnerability, the flood area limit ranges from 8.93 ha to 16.80 ha, the maximum flood depth limit ranges from 0.57 m to 0.90 m, and the maximum flood velocity limit ranges from 0.21 m/sec to 0.35 m/sec. For areas with moderate vulnerability, the flood area limit ranges from 16.80 ha to 24.68 ha, the maximum flood depth limit ranges from 0.90 m to 1.23 m, and the maximum flood velocity limit ranges from 0.35 m/sec to 0.50 m/sec. For areas with high vulnerability, the flood area limit ranges from 24.68 ha to 32.55 ha, the maximum flood depth limit ranges from 1.23 m to 1.55 m, and the maximum flood velocity limit ranges from 0.50 m/sec to 0.64 m/sec.</span></em></p>

Geophysical modelling of the Bjerkreim–Lobe, southern Norway

SUMMARY The Bjerkreim–Sokndal (BKS) intrusion in southern Norway has been studied for decades due to the presence of magnetic remanence creating anomalies 12 000 nT below background as measured by airborne magnetic surveys. The strong magnetic remanence also makes the BKS intrusion a good Earth analogue for remote studies of planets that have prominent magnetic signatures, such as Martian geological environments. Although numerous geophysical surveys and samples have been collected in the area, there are limited 3-D geological interpretations of the subsurface. Here, we used existing geophysical data to conduct forward and inversion modelling of the Bjerkreim lobe to investigate the subsurface geometry of the BKS intrusion. An extensive petrophysical property compilation was used as input data for the models, in combination with airborne magnetics and digital elevation models. This petrophysical compilation was initially analysed using principal component analysis to understand which variables would have the greatest impact on the models. Forward and inversion modelling show that cross-cutting jotunite bodies, and small anorthosite blocks within the Bjerkreim lobe have a limited depth extent of 1 km. Massive and foliated anorthosites to the west of the Bjerkreim lobe extend to depths greater than 4 km indicating that the BKS intruded into these anorthosites. Complications in magnetic field fitting during the forward modelling of megacyclic units with strong magnetic remanence and the results from a new ground magnetic survey support the need to revisit mapped contacts of the cyclical units.

Exploring altered bovine sperm trajectories by sperm tracking in unconfined conditions.

Mammalian sperm motility is getting more relevant due to rising infertility rates worldwide, generating the need to improve conventional analysis and diagnostic approaches. Nowadays, computer assisted sperm analysis (CASA) technologies represent a popular alternative to manual examination which is generally performed by observing sperm motility in very confined geometries. However, under physiological conditions, sperm describe three-dimensional motility patterns which are not well reconstructed by the limited depth of standard acquisition chambers. Therefore, affordable and more versatile alternatives are needed. Here, a motility analysis in unconfined conditions is proposed. In details, the analysis is characterized by a significant longer duration -with respect to conventional systems- with the aim to observe eventually altered motility patterns. Brightfield acquisition in rectangular glass capillaries captured frozen-thawed bovine spermatozoa which were analyzed by means of a self-written tracking routine and classified in sub-populations, based on their curvilinear velocity. To test the versatility of our approach, cypermethrin -a commonly used pesticides- known to be responsible for changes in sperm motility was employed, assessing its effect at three different time-steps. Experimental results showed that such drug induces an increase in sperm velocity and progressiveness as well as circular pattern formation, likely independent of wall interactions. Moreover, this resulted in a redistribution of sperm with the rapid class declining in number with time, but still showing an overall velocity increase. The flexibility of the approach permits parameter modifications with the experimental needs, allowing us to conduct a comprehensive examination of sperm motility. This adaptability facilitated data acquisition which can be computed at different frame rates, extended time periods, and within deeper observation chambers. The suggested approach for sperm analysis exhibits potential as a valuable augmentation to current diagnostic instruments.

In Vivo Microwave-Induced Thermoacoustic Endoscopy for Colorectal Tumor Detection in Deep Tissue.

Optical endoscopy, as one of the common clinical diagnostic modalities, provides irreplaceable advantages in the diagnosis and treatment of internal organs. However, the approach is limited to the characterization of superficial tissues due to the strong optical scattering properties of tissue. In this work, a microwave-induced thermoacoustic (TA) endoscope (MTAE) was developed and evaluated. The MTAE system integrated a homemade monopole sleeve antenna (diameter = 7 mm) for providing homogenized pulsed microwave irradiation to induce a TA signal in the colorectal cavity and a side-viewing focus ultrasonic transducer (diameter = 3 mm) for detecting the TA signal in the ultrasonic spectrum to construct the image. Our MTAE, system combined microwave excitation and acoustic detection; produced images with dielectric contrast and high spatial resolution at several centimeters deep in soft tissues, overcome the current limitations of the imaging depth of optical endoscopy and mechanical wave-based imaging contrast of ultrasound endoscopy, and had the ability to extract complete features for deep location tumors that could be infiltrating and invading adjacent structures. The practical feasibility of the MTAE system was evaluated i n vivo with rabbits having colorectal tumors. The results demonstrated that colorectal tumor progression could be visualized from the changes in electromagnetic parameters of the tissue via MTAE, showing its potential clinical application.

Ultrasound mediated sonochemical internalization (SCI): overcoming the depth limitations of light-based therapies

SignificanceFocused ultrasound activation of sonosensitizers i.e. sonodynamic therapy (SDT) is an alternative to light-activated photodynamic therapy (PDT). Sonochemical internalization (SCI), is comparable to light based photochemical internalization (PCI) but without the intrinsic drawback of limited penetration depth of light in biological tissues including the skull. ApproachSCI experiments were performed both in vitro on monolayers and in vivo, in a rat breast tumor model, using the sononsensitizer AlPcS2a and the drug bleomycin (BLM). Resultsin vitro; Growth inhibition of tumor cells in monolayer was significantly greater than that seen with either BLM or SDT acting alone. Similar results were also seen in vivo, with significant reduction in breast tumor development following BLM-SCI ConclusionThe synergist effect of SCI, employing relatively low drug concentrations and focused ultrasound power levels, would reduce the problems of nonspecific tissue damage caused by thermal effects at high power and unwanted systemic drug side effects.

In situ assembly FeS2-tetrathiomolybdate nanosheets for imaging-guided tumor vascular collapse and amplified catalytic therapy

Catalytic therapy has recently gained considerable attention as a novel tumor microenvironment (TME)-responsive treatment. While conventional nano-catalysts have demonstrated the ability to induce the death of tumor cells through oxidative damage via the generation of reactive oxygen species (ROS), their therapeutic efficacy is impeded by several factors, including limited tissue penetration depth and suboptimal catalytic efficiency. Herein, the FeS2-tetrathiomolybdate (FeS2-TTM) nanosheet was synthesized via in-situ self-assembled in the specific redox TME using metal precursors of divalent iron and tetrathiomolybdate, and these metal precursors could easily enter tumor cells through vascular penetration to avoid the blood-brain barrier. This nanosheet has been proved to possess peroxidase (POD)-like catalytic activity, which overcomes the limitations of traditional nanoparticals by the bimetallic electron transfer effect in the TME to amplify the catalytic treatment effect. Importantly, it retains the chelating copper characteristics of TTM, and inhibits tumor angiogenesis by depriving the necessary copper in cells and angiogenesis, resulting in vascular embolization to cause tumor blood vessels to collapse. Additionally, it can also act as a nanoprobe that supports both real-time fluorescence imaging monitoring and T1/T2 dual-modality magnetic resonance imaging (MRI). As a promising nanomaterial, this new type of in-situ self-assembled nanosheet provides more varieties for the construction of an integrative platform of tumor diagnosis and treatment.

Can digital economy development contribute to urban carbon emission reduction? - Empirical evidence from China

In the context of global digitalization, fostering the expansion of the digital economy holds immense importance in promoting energy efficiency and reducing emissions. Utilizing a sample of 281 prefecture-level cities in China from 2003 to 2019, this research analyzes the impact of the digital economy on urban carbon emissions in China. This study employs various methods, including principal component analysis, fixed-impact model, and mediating effect model. Based on the research findings, the development of the digital economy has the potential to significantly reduce carbon emissions in metropolitan areas. Moreover, these effects are especially noticeable in cities located to the east of the Hu Huanyong Line. These cities are characterized by limited reliance on resources and a high level of marketization. Further research reveals that promoting technical innovation and modernizing industrial structures can reduce the intensity of carbon emissions in metropolitan areas. This study provides empirical evidence supporting the effective reduction of carbon emissions in developing countries during the evolution of the digital economy. It acts as a crucial cornerstone for guiding policies and executing strategies aimed at fostering top-tier economic development in the future. The findings of this study confirm the inhibitory effect of the digital economy on urban carbon emission intensity. However, this study has limitations in data samples, research scope, and depth of mechanism analysis, which prevent a full exploration of the spatial spillover effect of the digital economy and other factors. Therefore, the conclusions drawn in this study can only provide empirical evidence for identifying the relationship between the digital economy and carbon emission intensity to a certain extent. Future research should aim to expand on these aspects.

Meaningful Synergy in E-learning Integrating Environmental Awareness and Project-Based Learning in EFL

The study investigates EFL e-learning project-based education and environmental awareness. Despite limited participation and technology concerns, e-learning is evolving. This study supports "green awareness" in higher education institutions, promotes environmental responsibility and global citizenship. Our study combines meaningful learning, project-based pedagogy, and online EFL instruction with active engagement. According to this study, project-based education and environmental awareness can boost EFL e-learning learners' involvement. These 300 university-level EFL students are being studied holistically with ADDIE. This comprises need analysis, design, material development, classroom implementation, and impact assessment. According to research, incorporating "green business" into online sessions increases student participation. A poll found that intervention promotes environmental consciousness. According to interviews, environmental awareness and sustainability motivate students to create environmentally responsible solutions. Despite limitations in depth and sample size, well-designed interventions increase online learning engagement. The findings contribute to more effective online education methods, instructional design, and student involvement investigations.

Visualizing cortical blood perfusion after photothrombotic stroke in vivo by needle-shaped beam optical coherence tomography angiography

Optical imaging techniques provide low-cost, non-radiative images with high spatiotemporal resolution, making them advantageous for long-term dynamic observation of blood perfusion in stroke research and other brain studies compared to non-optical methods. However, high-resolution imaging in optical microscopy fundamentally requires a tight optical focus, and thus a limited depth of field (DOF). Consequently, large-scale, non-stitched, high-resolution images of curved surfaces, like brains, are difficult to acquire without z-axis scanning. To overcome this limitation, we developed a needle-shaped beam optical coherence tomography angiography (NB-OCTA) system, and for the first time, achieved a volumetric resolution of less than 8 μm in a non-stitched volume space of 6.4 mm × 4 mm × 620 μm in vivo. This system captures the distribution of blood vessels at 3.4-times larger depths than normal OCTA equipped with a Gaussian beam (GB-OCTA). We then employed NB-OCTA to perform long-term observation of cortical blood perfusion after stroke in vivo, and quantitatively analyzed the vessel area density (VAD) and the diameters of representative vessels in different regions over 10 days, revealing different spatiotemporal dynamics in the acute, sub-acute and chronic phase of post-ischemic revascularization. Benefiting from our NB-OCTA, we revealed that the recovery process is not only the result of spontaneous reperfusion, but also the formation of new vessels. This study provides visual and mechanistic insights into strokes and helps to deepen our understanding of the spontaneous response of brain after stroke.

Automatic detection of quartz glass subsurface defects by laser scattering method based on an ellipsoidal mirror.

With the improvement of quality requirements of optical components, the detection of subsurface defects of optical components has become a key technology. The existing detection methods still have some limitations in detection depth and detection efficiency. In this paper, a defect scattering light collection method based on ellipsoidal mirror model is used to analyze the scattering light collection efficiency under different experimental conditions theoretically, and the favorable conditions for improving the scattering light collection are proposed. After simulation verification, the use of ellipsoidal reflectors to collect scattered light can effectively avoid the impact of surface defects compared to lenses. At the same time, an experimental system based on this method is set up to filter the stray light by mean filtering method. The system detected three scratches (2μm in width and 252nm in depth) on the underside of a piece of quartz glass. The results show that the system can clearly detect the subsurface defects of optical components.

Multifunctional Inorganic-Organic Composite Carriers for Synergistic Dual Therapy of Melanoma.

Many methods for cancer treatment have been developed. Among them photothermal therapy (PTT) has drawn the most significant attention due to its noninvasiveness, remote control activation, and low side effects. However, a limited depth of light penetration of PTT is the main drawback. To improve the therapeutic efficiency, the development of combined PTT with other therapeutic agents is highly desirable. In this work, we have designed multifunctional composite carriers based on polylactic acid (PLA) particles decorated with gold nanorods (Au NRs) as nanoheaters and selenium nanoparticles (Se NPs) for reactive oxygen species (ROS) production in order to perform a combined PTT against B16-F10 melanoma. To do this, we have optimized the synthesis of PLA particles modified with Se NPs and Au NRs (PLA-Se:Au), studied the cellular interactions of PLA particles with B16-F10 cells, and analyzed in vivo biodistribution and tumor inhibition efficiency. The results of in vitro and in vivo experiments demonstrated the synergistic effect from ROS induced by Se NPs and the heating from Au NRs. In melanoma tumor-bearing mice, intratumoral injection of PLA-Se:Au followed by laser irradiation leads to almost complete elimination of tumor tissues. Thus, the optimal photothermal properties and ROS-generating capacity allow us to recommend PLA-Se:Au as a promising candidate for the development of the combined PTT against melanoma.