Penetration Depth Research Articles

ZGSO:Cr3+,Ni2+ Persistent Phosphors with Dual Emission in NIR-I and SWIR Ranges for Bio-Imaging Applications.

Persistent luminescence (PersL) is widely used for near infrared (NIR-I, 650-950nm) imaging as they allow getting images without background. Bio-imaging in the second shortwave-infrared region SWIR-II (NIR-II, 1000-1400nm) is less widespread but is growing as it offers the advantages of low photon scattering, increased in vivo penetration depth, and improved imaging clarity. In this work, the preparation and the complete optical properties of a new material is reported, Zn1.33Ga1.33Ni0.005Cr0.005Sn0.33O3.995 (ZGSO:Cr3+, Ni2+) able of emitting in both deep-red/NIR-I and SWIR (NIR-II) and shows its potential in bioimaging. ZGSO:Cr3+, Ni2+ can be excited using different sources such as X-rays, UV, and visible light to emit persistent signals in dual biological windows (dual-BW). By integrating an energy transfer process from Cr3+ to Ni2+ within this newly synthesized material, the influence of co-dopants on signal intensity and emission wavelengths is sought to explore. PersL at ≈700nm (NIR-I) and ≈1300nm (NIR-II) have been tested in preliminary bioimaging experiments using different protocols, allowing signal detection with good spatial resolution and depth sensitivity. The dual-BW PersL imaging strategy expands the toolbox for highly accurate analysis and has, for the first time, allowed access to accurately high-resolution sensing, and tracing.

Application of Box-Behnken design for the optimization of Khellin-loaded ethosomes formulation for the management of psoriasis in mice

The objective of the present study was to develop and optimize Khellin-loaded ethosomes formulation to enhance the topical delivery of Khellin for the management of psoriasis. Based on vesicle size, polydispersity (PdI) and encapsulation efficiency, the formulation was optimized using the "3-factor 3-level", Box-Behnken design (BBD). Antioxidant, Anti-inflammatory and Anti-psoriatic activity were further assessed for the optimized formulation. The optimized formulation carried vesicles with a size of 214.64 ± 0.04 nm, PdI 0.387 ± 0.001 and an encapsulation efficiency of 68.38 ± 0.01%. Rhodamine-B loaded formulation was applied to mice skin, and the penetration depth was measured using confocal laser scanning microscopy (CLSM). It was found that the Rhodamine-B solution penetrated mice’s skin to a depth of 20.0 µm. However, the Rhodamine-B loaded ethosomes formulation penetrated mice’s skin to a depth of 55.0 µm. Further, the Khellin-loaded ethosomes formulation possessed strong antioxidant activity, presented a good reduction in paw edema, and showed good anti-inflammatory activity. In addition, the prepared Khellin-loaded ethosomes formulation exhibited considerable effects against psoriasis.

Complex-valued scatter compensation in nonlinear microscopy

Nonlinear, i.e., multiphoton microscopy is a powerful technique for imaging deep into biological tissues. Its penetration depth can be increased further using adaptive optics. In this work, we present a fast, feedback-based adaptive-optics algorithm, termed C-DASH, for multiphoton imaging through multiple-scattering media. C-DASH utilizes complex-valued light shaping (i.e., joint shaping of amplitude and phase), which offers several advantages over phase-only techniques: it converges faster, it delivers higher image quality enhancement, it shows a robust performance largely insensitive to the axial position of the correction plane, and it has a higher ability to cope with, on the one hand, scattering media that vary over time and, on the other hand, scattering media that are partially absorbing. Furthermore, our method is practically self-aligning. We also present a simple way to implement C-DASH using a single reflection off a phase-only spatial light modulator. We provide a thorough characterization of our method, presenting results of numerical simulations as well as two-photon excited fluorescence imaging experiments. Published by the American Physical Society 2024

Toward Upconversion (Yb-Er) and near-Infrared (Yb-Ho-Er, Nd-Yb) Thermometry with Sea Urchin Type GdPO4 Nanoarchitectures.

In recent years, optical temperature probes operating in the second near-infrared (BW-II) and third near-infrared (BW-III) biological windows have garnered significant attention in the scientific community. For biological applications these probes offer distinct advantages, including enhanced tissue penetration depth, minimal autofluorescence, and a remarkable improvement in imaging sensitivity and spatial resolution. Moving toward theranostic applications, there is a growing demand for the development of materials that integrate both BW-II and BW-III thermometry systems with drug delivery functionalities. In this study, we concentrate on the development of GdPO4 materials, utilizing both hard and sacrificial template routes to synthesize (hollow) GdPO4 porous sea urchin-like particles. We first investigated the development of a Boltzmann-type thermometer utilizing an Yb-Er upconversion system, designed to operate within the physiological temperature range. Our exploration extends to the potential of GdPO4 particles in near-infrared (NIR) thermometry, spanning the first, second, and third biological windows with systems like Yb-Ho-Er, Nd-Yb, and Ho-Yb, respectively. We further examined the temperature impact of the Yb-Ho-Er system on the NIR emission within a biologically relevant setting, using a phantom that replicates biological tissue. Furthermore, we illustrate the successful loading of these materials with doxorubicin (DOX·HCl), a model anticancer drug, showing these particles exhibit pH-dependent DOX release. This demonstrates the versatility of these materials as upconversion and NIR thermometers while simultaneously serving as an on-demand drug carrier. The investigation involves assessing their cytotoxicity on specific human cells (Normal Human Dermal Fibroblasts (NHDFs)), to determine their viability for potential use in biological applications. The study also investigates how effectively loading the particles with DOX enables targeted delivery to a cellular model of lymphoma (Jurkat E6-1), resulting in cell death. This comprehensive analysis highlights the promising potential of GdPO4 particles for medical applications.

Variable-energy cocktail beam technology for investigating synergistic damage in nuclear materials on LEAF platform

This study addresses the critical issue of synergistic radiation damage in structural materials of fusion reactors, focusing on the interaction between the displacement defects and transmutation-produced hydrogen and helium. These effects are simulated and investigated by employing the advanced multi-beam ion implantation capabilities of the LEAF (Low Energy high intensity highly charged ion Accelerator Facility) platform. Firstly, high-intensity cocktail beams, such as “4He+ and 56Fe14+" and “4He+ and 58Ni15+", are generated and characterized successfully. Then, a complex radiation environment is mimicked within the fusion reactors by applying variable-energy irradiation. Secondly, similar penetration depths for different ions, which are crucial for studying synergistic effects, are obtained by precisely controlling the energy of the cocktail beams through the innovative energy modulation system of the LEAF platform. Finally, the post-irradiation analyses, performed by using the transmission electron microscopy (TEM) and nanoindentation, revealed distinct microstructural changes and alterations in material properties, providing insights into the degradation mechanisms under irradiation. This work not only generates diverse and high-intensity “cocktail” ion beams but also achieves rapid energy switching of the beams. Further, the work is expected to pave the way for the implementation of a novel multi-beam irradiation technique in advanced heavy-ion linear accelerators, and also to provide innovative experimental methods and technical support for studying the synergistic effects of nuclear materials.

Investigation of the Influence of Cutter Geometry on the Cutting Forces in Soft–Hard Composite Ground by Tunnel Boring Machine Cutters

Tunnel Boring Machines (TBMs) are integral to modern underground engineering construction, offering enhanced safety and efficiency. However, TBMs often face challenges in complex geological conditions, such as composite strata, resulting in reduced advancement speed and increased cutter wear. This study investigates the rock-breaking characteristics of TBM disc cutters in composite strata through numerical simulations using the Particle Flow Code (PFC) 5.0 software. Focusing on the Jinan Metro Line 6, the research analyzes cutter forces, rock crack propagation, and the impact of cutter edge shapes on rock-breaking efficiency. The discrete element method (DEM) is employed to simulate microscopic behaviors of rocks, providing insights into crack formation, expansion, and failure. This study’s findings reveal that cutter design and operational parameters can significantly influence cutter lifespan and efficiency. By modifying cutter spacing and penetration depth, enhancing rock-breaking efficiency, and grouting softer layers, TBMs can maintain effective excavation in composite strata. The study establishes a comprehensive understanding of the interplay between TBM cutters and complex geological conditions, offering actionable strategies to enhance TBM performance and mitigate cutter damage.

Experimental study on the buffering mechanism of EPS bead-sand cushions under single and multiple impacts

As a main functional component of rock sheds in rockfall protection projects, traditional sand cushions have shortcomings such as heavy weight and weak buffering capacity. EPS bead-sand cushion can effectively solve these problems, but its buffering mechanism has not been fully revealed. In this study, a series of impact tests were carried out to investigate the performance of EPS bead-sand cushions with different EPS bead contents, and the evolutions of rockfall impact force, penetration depth, earth pressure, and slab vibration under single impact and multiple impacts were comparatively analyzed. The results show that with the addition of EPS beads, the maximum impact force, the peak earth pressure, and the vibration acceleration are significantly reduced. However, the cushion with high EPS bead content is at risk of being penetrated under high energy or multiple impacts, leading to excessive concentration of impact stresses. Furthermore, the EPS beads can alleviate the hardening of the sand cushion under impact through their deformation coordination, but excessive penetration should be prevented in the design of EPS bead-sand cushions. On this basis, combined with traditional sand cushion design theory, an estimation method for the maximum impact force applicable to EPS bead-sand cushion was proposed. The research results can provide a reference for the design and optimization of cushions in actual projects.

Utilizing fractional lasers and tirbanibulin ointment to treat squamous and basal cell carcinomas

Keratinocyte carcinoma is the most common form of cancer in the United States. Often treated by surgical excision, electrodessication and curettage, or Mohs surgery, treatment can frequently leave patients with a scar and can be time consuming and inconvenient for both patients and healthcare providers. Utilizing non-ablative fractional laser therapy followed by tirbanibulin ointment, we treated 30 basal and/or squamous cell carcinomas on 23 patients over the age of 50 with varying skin types. Multiple areas of the face and body, and carcinomas at differing stages, were treated. We maximized the depth of penetration of the fractional laser by using bulk heating methods while simultaneously optimizing cosmetic results. This is an ongoing study as we continue to track the progress of our participants. Thus far, no clinical or histological recurrence of carcinoma has been found in any of the treated sites.

Review of high-precision femtosecond laser materials processing for fabricating microstructures: Effects of laser parameters on processing quality, ablation efficiency, and microhole shape

Femtosecond lasers are promising tools for achieving high-precision processing of thin materials without causing any thermal surface damage and bulk distortion. However, thermal damage can occur even with ultrashort laser pulses. This is because of high electron penetration depth and heat accumulation at high fluence and high repetition rate. Nanoparticle redeposition can be dramatically altered with variation in repetition rate. The symmetry of microholes and ablation efficiency vary with laser polarization. The laser wavelength affects the ablation efficiency and surface roughness. Therefore, understanding these laser–matter interactions that depend on the laser parameters is essential for high-precision laser processing. This article reviews laser–matter interactions in the 64FeNi alloy, as well as analytical models for designing the desired hole size and taper angles. This can help establish strategies for creating various high-precision microstructures using femtosecond lasers.

Structural, morphological and optical properties of the La2W2O9/Fe2O3 composite for UV-shielding applications

Currently, research has been conducted on the individual oxides La2W2O9 and Fe2O3 but not on its composite form. Using a solid-state reaction technique, a La2W2O9/Fe2O3 composite was created. A particular calcination cycle was followed by mixing the raw precursors. Scanning electron microscopy (SEM) was used to investigate the morphological microstructure, and X-ray diffraction (XRD) was used to examine the structural characteristics. The thermal and gravimetric properties were examined via differential thermal analysis (DTA) and thermogravimetric analysis (TGA). The optical characteristics were investigated via UV–visible spectroscopy, which investigated included the transmittance, absorbance, absorption coefficient, band gap (Eg), penetration depth (β), Urbach energy (EU), refractive index, optical conductivity, and dielectric function. These findings indicate that the optical properties improved after the addition of Fe2O3 compared with those of pure La2W2O9. The La2W2O9/Fe2O3 composite holds promise as a prospective material for use in the fields of sunscreen products, UV shielding or solar filtration.

Discrete element model of low-velocity projectile penetration and impact crater on granular bed

The present study investigates the low-velocity impacts of a spherical projectile into a bed of spherical particles using Discrete Element Method (DEM) simulations and laboratory experiments. The findings reveal intricate forces and energy transformations, indicating the phenomena leading to projectile impact, penetration, cessation, and crater formation. The DEM result indicates that the penetration stopping time of the projectile is not influenced by impact velocity. Further, simulations show that projectile penetration depth correlates with 1/2.7 power of total impact height, while crater diameter and depth scale with 1/4.32 power of nondimensional impact energy. The shape of the resulting crater appears independent of impact velocity and the maximum diameter of the fluidized region varies with the 1/2.68 power of impact velocity. Experimental validation confirms the accuracy of predicted penetration depths and crater diameters, enhancing confidence in DEM simulations. These findings extend scaling laws and reveal the influence of larger particles on low-velocity impact dynamics, addressing unexplored aspects of granular cratering.

Numerical Modeling of Vortex-Based Superconducting Memory Cells: Dynamics and Geometrical Optimization.

The lack of dense random-access memory is one of the main obstacles to the development of digital superconducting computers. It has been suggested that AVRAM cells, based on the storage of a single Abrikosov vortex-the smallest quantized object in superconductors-can enable drastic miniaturization to the nanometer scale. In this work, we present the numerical modeling of such cells using time-dependent Ginzburg-Landau equations. The cell represents a fluxonic quantum dot containing a small superconducting island, an asymmetric notch for the vortex entrance, a guiding track, and a vortex trap. We determine the optimal geometrical parameters for operation at zero magnetic field and the conditions for controllable vortex manipulation by short current pulses. We report ultrafast vortex motion with velocities more than an order of magnitude faster than those expected for macroscopic superconductors. This phenomenon is attributed to strong interactions with the edges of a mesoscopic island, combined with the nonlinear reduction of flux-flow viscosity due to the nonequilibrium effects in the track. Our results show that such cells can be scaled down to sizes comparable to the London penetration depth, ∼100 nm, and can enable ultrafast switching on the picosecond scale with ultralow energy per operation, ∼10-19 J.

A review of label-free photonics-based techniques for cancer detection in the digestive and urinary systems

Abstract For a long time, it has been known that optics can provide a broad range of tools for addressing clinical needs, particularly diagnostics. Optical techniques can help in identifying diseases and detecting pathological tissues with non/minimally invasive and label-free methods. Given the current limitations of standard clinical procedures, such an approach could provide a powerful tool in detecting gastrointestinal and bladder cancers. However, each technique has serious limitations regarding one or more of the following features: biomarker sensitivity, penetration depth, acquisition times, or adaptation to the clinical environment. Hence there is an increasing need for approaches and instruments based on the concept of multimodality; in this regard, we review the application of different imaging/spectroscopy tools and methods operating in the first two optical windows (SHG, SPEF, TPEF, THG, 3PEF, CARS, Raman and reflectance) for tumour detection in the digestive and urinary systems. This article also explores the possibility of exploiting the third bio-tissue transmission window (1600-1900 nm) by reviewing state of the art in ultrafast laser sources development. Finally, we summarise the most recent results in developing multiphoton endoscopes – a key element for clinical in vivo translation of photonics-based diagnostics.

Lifting of Gap Nodes by Disorder in Tetragonal FeSe_{1-x}S_{x} Superconductors.

The observation of time-reversal symmetry breaking and large residual density of states in tetragonal FeSe_{1-x}S_{x} suggests a novel type of ultranodal superconducting state with Bogoliubov Fermi surfaces (BFSs). Although such BFSs in centrosymmetric superconductors are expected to be topologically protected, the impurity effect of this exotic superconducting state remains elusive experimentally. Here, we investigate the impact of controlled defects introduced by electron irradiation on the superconducting state of tetragonal FeSe_{1-x}S_{x} (0.18≤x≤0.25). The temperature dependence of magnetic penetration depth is initially consistent with a model with BFSs in the pristine sample. After irradiation, we observe a nonmonotonic evolution of low-energy excitations with impurity concentrations. This nonmonotonic change indicates a transition from nodal to nodeless, culminating in gapless with Andreev bound states, reminiscent of the nodal s_{±} case. This points to the accidental nature of the possible BFSs in tetragonal FeSe_{1-x}S_{x}, which are susceptible to disruption by the disorder.

Ablation options for sub-epicardially located ventricular substrates responsible for ventricular tachycardia: where is it all headed?

Patients with nonischemic and ischemic cardiomyopathy (NICM and ICM) exhibit re-entrant tachycardias related to scar tissue in subepicardial, in addition to typical subendocardial locations. Control of ventricular arrhythmias related to these targets has remained elusive despite advances in mapping and ablation technology. Percutaneous epicardial ablation is the standard after failed endocardial ventricular ablation, but recurrence rates are disappointing. Pulsed-field energy has been associated with coronary artery spasm and therefore may be less suitable for epicardial ablation. Commercially available energy sources, including pulsed-field, have limited depths of myocardial penetration when applied epicardially. Lateral volumetric thermal spreading of ablation injury is associated with decreasing depth of ablation and is difficult to control. A new cryoablation technology based on liquid helium and developed specifically for epicardial work may be able to overcome these limitations. Ablation strategies that can improve lesion formation in subepicardial ventricular myocardium may improve outcomes of ablation in nonsubendocardial NICM and ICM targets.

Experimental evidence and calculation of the penetration depth of acyl chloride reagent and molecular expansion in a dense layer of PVA coated on a paperboard after chromatogeny grafting

Experimental evidence and calculation of the penetration depth of acyl chloride reagent and molecular expansion in a dense layer of PVA coated on a paperboard after chromatogeny grafting

Augmenting bonding properties of OSB and Chinese fir hybrid cross-laminated timber by sandblasting pretreatment

The investigation was conducted into the adhesive performance within hybrid cross-laminated timber (HCLT) composed of sandblasted Chinese fir and oriented strand board (OSB) which was originally covered by cured adhesive during the manufacture leading to very fragile bonding. HCLT specimens with three layers were bonded utilizing three structural adhesives which were polyresorcinol formaldehyde (PRF), polyurethane (PUR), and polyisocyanate (EPI). Surface roughness and wettability testing ascertained that sandblasting could effectively change the original resin layer and microtopography on the surface of OSB laminates, significantly modified the level of roughness on the surface, thereby providing a basis for vertical spreading and permeating of the adhesives. Sandblasting pretreatment consistently augmented the dry bonding shear strength about all the three adhesives, achieving the most substantial increases of 53 %, 39 %, and 37 % for PRF, PUR, and EPI, respectively. The pretreatment further reducing delamination rates to about a half in cyclic delamination tests of all three adhesives. Fluorescence microscopy detection of the bonding interfaces revealed a significant increase in adhesive penetration depth which had been further confirmed by the bonding interface thickness measurement. Surface roughness generally had a negative effect on dry shear bonding strength, especially with EPI adhesive, while surface wettability was positively correlated with bonding strength and adhesive layer thickness. This study introduced an environmental and efficient method to enhance the bonding performance of HCLT.

Impact of ionization and transport on pedestal density structure in DIII-D and Alcator C-Mod

Abstract This paper investigates the role of ionization on the pedestal structure using both measurements and modeling for H-mode plasmas on DIII-D and Alcator C-Mod to enhance our ability to predict pedestal behavior in future pilot plants. The impact of the neutral penetration depth on the pedestal density is investigated using dimensionally matching hydrogen and deuterium DIII-D H-mode discharges at low and high electron density. The DIII-D Lyman-α diagnostic measurements show that hydrogen neutrals penetrate deeper inside the plasma on both the high field and low field side, while the pedestal electron density structure is similar for both isotopes. However, as the opaqueness increases we observe that the pedestal density gradient becomes stiff, similar to prior observations on DIII-D and C-Mod (Mordijck 2020 Nuclear Fusion 60 082006). In addition, these results also confirm prior measured and modeled poloidal asymmetries in neutral densities, indicating that to make transport predictions, 2D neutral modeling is necessary. The first direct validation of SOLPS-ITER for the measured brightness, emissivity and neutral densities for three different confinement regimes on C-Mod is introduced. The SOLPS-ITER model shows good agreement, within the constrains of the model for all regimes. In addition, a comparison of SOLPS-ITER modeling for DIII-D and C-Mod shows that as opaqueness increases, the role of divertor fueling and thus poloidal asymmetries in the neutral density profiles decreases. Based on these experimental and modeling results we estimate the size of a potential particle pinch using typical values for the diffusion coefficient for both DIII-D and C-Mod H-mode discharges.

NIR-II Anti-Stokes Luminescence Nanocrystals with 1710 nm Excitation for in vivo Bioimaging.

Anti-Stokes luminescence (ASL) based on lanthanide nanocrystals holds immense promise for in vivo optical imaging and bio-detection, which benefits from filtered autofluorescence. However, the current longest emission and excitation wavelengths of lanthanide ASL system were shorter than 1200 nm and 1532 nm, respectively, which limited tissue penetration depth and caused low signal-to-noise ratio (SNR) of in vivo imaging due to tissue scattering and water absorption. In this work, we extended the excitation wavelength to 1710 nm with the second near-infrared (NIR-II, 1000-1700 nm) emission up to 1650 nm through a novel ASL nanocrystal LiYF4:10%Tm@LiYF4:70%Er@LiYF4. Compared with 1532 nm excited ASL nanoprobes, the 1710 nm excited nanocrystals could improve in vivo imaging SNR by 12.72 folds. Based on this excellent imaging performance of the proposed ASL nanoprobes, three-channel in vivo dynamic multiplexed imaging was achieved, which quantitatively revealed metabolic rates of intestinal dynamics and liver enrichment under anesthetized and awake states. This innovative ASL nanoprobes and dynamic multiplexed imaging technology would be conducive to optimizing dosing regimen and treatment plans across various physiological conditions.

Supernormal Temperature Sensing Performance Realized through the Blue Emitting Level of Er3+ along with Detection Ability in Deep Tissues.

Fluorescence intensity ratio (FIR)-type optical thermometers based on thermally coupled energy levels (TCLs) of rare earth ions are suitable candidates for noncontact temperature detection in living organisms, microelectronics apparatus, and so forth. Therefore, the improvement of the thermometric sensitivity of TCL-based thermometers has become a research hotspot in recent years. Herein, ultrahigh sensitivity and outstanding resolution for temperature sensing have been realized in YNbO4: Yb3+/Er3+. Unusually, the thermally coupled three-level system of Er3+: 4F7/2/2H11/2/4S3/2 is first employed for optical thermometry based on FIR technology. A supernormal thermometric sensitivity of 2.67% K-1 is obtained from the thermally coupled 4F7/2 and 4S3/2 states due to the large energy gap between them, significantly surpassing that of most temperature sensors in the same category. Furthermore, the existence of the intermediate level 2H11/2 can effectively prevent the decoupling effect between 4F7/2 and 4S3/2. Additionally, the temperature sensing behavior realized by the Stark sublevels of the Er3+: 4I13/2 → 4I15/2 transition, with a penetration depth of 8 mm, shows the potential of temperature measurement in deep biological tissues, benefiting from its excitation and emission wavelengths located in the biological window. All of the data reveal that YNbO4: Yb3+/Er3+ is an ultrasensitive optical thermometer and exhibits the capacity of temperature detection in deep tissues.