BACKGROUND: Ultra high dose rate (UHDR) radiotherapy using ridge filter is a new treatment modality known as conformal FLASH that, when optimized for dose, dose rate (DR), and linear energy transfer (LET), has the potential to reduce damage to healthy tissue without sacrificing tumor killing efficacy via the FLASH effect.
OBJECTIVE: Clinical implementation of conformal FLASH proton therapy has been limited by quality assurance (QA) challenges, which include direct measurement of UHDR and LET. Voxel DR distributions and LET spectra at planning target margins are paramount to the DR/LET-related sparing of organs at risk. We hereby present a methodology to achieve experimental validation of these parameters.
METHODS: Dose, DR, and LET were measured for a conformal FLASH treatment plan involving a 250-MeV proton beam and a 3D-printed ridge filter designed to uniformly irradiate a spherical target. We measured dose and DR simultaneously using a 4D multi-layer strip ionization chamber (MLSIC) under UHDR conditions. Additionally, we developed an \"under-sample and recover (USRe)\" technique for a high-resolution pixelated semiconductor detector, Timepix3, to avoid event pile-up and to correct measured LET at high-proton-flux locations without undesirable beam modifications. Confirmation of these measurements was done using a MatriXX PT detector and by Monte Carlo (MC) simulations.
RESULTS: MC conformal FLASH computed doses had gamma passing rates of >95% (3 mm/3% criteria) when compared to MatriXX PT and MLSIC data. At the lateral margin, DR showed average agreement values within 0.3% of simulation at 100 Gy/s and fluctuations ∼10% at 15 Gy/s. LET spectra in the proximal, lateral, and distal margins had Bhattacharyya distances of <1.3%.
CONCLUSIONS: Our measurements with the MLSIC and Timepix3 detectors shown that the DR distributions for UHDR scenarios and LET spectra using USRe are in agreement with simulations. These results demonstrate that the methodology presented here can be used effectively for the experimental validation and QA of FLASH treatment plans.

UV sensing 3D printed optical fiber hydrogels provide a flexible and precise method of remotely of detecting exposure to UV radiations. The optical fibers were created using digital light processing 3D printing technique with hydrogel composites, including micro-sized photochromic dyes (pink, blue and their combination). When exposed to ultraviolet (UV) radiation, these dyes exhibited specific absorption characteristics, resulting in significant decreases in both reflection and transmittance mode spectra at 560 nm, 620 nm, and 590 nm. Optical fibers of lengths 1, 2, and 3 cm were manufactured in two orientations: vertical and horizontal. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were utilized to characterize the printed fiber probes. The optical performance of the fibers was tested using customized measurement setups. The reflection and transmission of the printed fibers reduced as the length increased due to optical losses. Reflection and transmisson loss of 20-40% can be observed when the length is increased from 1 to 3 cm. The maximum loss in reflection is observed for pink fiber in the presence of UV irradiation. Also, the type of powder used impacted the response and retraction time, whereas the mixed fiber showed the highest response time of 12-20 s under various conditions. The pink dye added fiber probes shows quick response to UV radiation. An increase in the response time is observed with increasing fiber length. The impact of printing orientation on the transmission and reflectance mode operations of optical fibers was assessed. In addition, the stability of the fiber probes are assesed using a green laser having wavelength 532 nm. This work comprehensively examines the optical properties, manufacturing procedures, and sensing capacities of UV-sensitive photochromic optical fiber sensors.

Regarding its structural and mechanical adaptability to bone defects, 3D printed (3DP) Ti6Al4V scaffolds are widely used in orthopedics now, purposed to restore the function and mechanical stability of impaired bone. In scaffold fabrication, surface modification is acknowledged as a reliable strategy to enhance the interface interaction between 3DP Ti6Al4V scaffold and bone. Despite its advantage in bone-Ti6Al4V bonding improvement, surface modification lacks the ability to induce bone in-growth efficiently as expected. As an attempt to overcome this challenge, in the current work the inner voids of 3DP Ti6Al4V scaffold were occupied by a gelatin/chitosan porous matrix, purposed to act as a platform for guiding bone ingrowth. Firstly, the gelatin/chitosan matrix was prepared via freeze-drying using genipin as a crosslinker, resulting in a trabecular bone-like interconnected porous network characterized with a gelatin/chitosan ratio dependent swelling capability, degradation and model anti-bacterial drug release behavior. Besides of that, gelatin in the matrix was witnessed to accelerate biomineralization in simulated body fluid. Secondly, a formulated gelatin/chitosan matrix was embedded into 3DP Ti6Al4V scaffold to generate a composite scaffold capable of inducing bone in-growth. The followed studies showed gelatin/chitosan matrix can endow the scaffold with good biological and sustained drug release properties, along with minimal change to the compressive strength of the scaffold. The in vivo experiment results revealed that after 4 weeks of implantation, more new bone formation was witnessed in the inner structure of the composite scaffold than the 3DP Ti6Al4V scaffold, with the average bone volume fraction (BV/TV) value increased from 24.09 % to 46.08 %, the average trabecular bone thickness (Tb. Th) value increased from 0.118 mm to 0.278 mm. Therefore, it was confirmed an inner matrix in 3DP Ti6Al4V scaffold played an essential role in guiding bone in-growth.

In food systems, proteins and polyphenols typically coexist in a non-covalent manner. However, the inherent rigid structure of proteins may hinder the binding sites of polyphenols, thereby limiting the strength of their interaction. In the study, magnetic field (MF) treatment was used to enhance non-covalent interactions between coconut globulin (CG) and tannic acid (TA) to improve protein flexibility, enhancing their functional properties without causing oxidation of polyphenols. Based on protein structure results, the interaction between CG and TA caused protein structure to unfold, exposing hydrophobic groups. Treatment with a MF, particularly at 3 mT, further promoted protein unfolding, as evidenced by a decrease in α-helix structure and an increase in coil random. These structural transformations led to the exposure of the internal binding site bound to TA and strengthening the CG-TA interaction (polyphenol binding degree increased from 62.3 to 68.2%). The characterization of molecular forces indicated that MF treatment strengthened hydrogen bonding-dominated non-covalent interactions between CG and TA, leading to improved molecular flexibility of the protein. Specifically, at a MF treatment at 3 mT, CG-TA colloidal particles with small size and high surface hydrophobicity exhibited optimal interfacial activity and wettability (as evidenced by a three-phase contact angle of 89.0°). Consequently, CG-TA-stabilized high internal phase Pickering emulsions (HIPPEs) with uniform droplets and dense gel networks at 3 mT. Furthermore, the utilization of HIPPEs in 3D printing resulted in consistent geometric shapes, uniform surface textures, and distinct printed layers, demonstrating superior printing stability. As a result, MF treatment at 3 mT was identified as the most favorable. This research provides novel insights into how proteins and polyphenols interact, thereby enabling natural proteins to be utilized in a variety of food applications.

OBJECTIVE: This study aims to design and fabricate a 3D printed heterogeneous paediatric head phantom and to customize a thorax phantom for radiotherapy dosimetry. Approach: This study designed, fabricated, and tested 3D printed radiotherapy phantoms that can simulate soft tissue, lung, brain, and bone. Various polymers were considered in designing the phantoms. Polylactic acid+, nylon, and plaster were used in simulating different tissue equivalence. Dimensional accuracy, and CT number were investigated. The phantoms were subjected to a complete radiotherapy clinical workflow. Several treatment plans were delivered in both the head and the thorax phantom from a simple single 6 MV beam, parallel opposed beams, and five-field intensity modulated radiotherapy (IMRT) beams. Dose measurements using an ionization chamber and radiochromic films were compared with the calculated doses of the Varian Eclipse treatment planning system (TPS). Main results: The fabricated heterogeneous phantoms represent paediatric human head and adult thorax based on its radiation attenuation and anatomy. The measured CT number ranges are within -786.23 ± 10.55, 0.98 ± 3.86, 129.51 ± 12.83, and 651.14 ± 47.76 HU for lung, water/brain, soft tissue, and bone, respectively. It has a good radiological imaging visual similarity relative to a real human head and thorax depicting soft tissue, lung, bone, and brain. The accumulated dose readings for both conformal radiotherapy and IMRT match with the TPS calculated dose within ±2% and ±4% for head and thorax phantom, respectively. The mean pass rate for all the plans delivered are above 90% for gamma analysis criterion of 3% / 3 mm. Significance and conclusion: The fabricated heterogeneous paediatric head and thorax phantoms are useful in Linac end-to-end radiotherapy quality assurance based on its CT image and measured radiation dose. The manufacturing and dosimetry workflow of this study can be utilized by other institutions for dosimetry and trainings. .

Endovascular treatment (EVT) using stents has become the primary option for severe cerebrovascular stenosis. However, considerable challenges remain to be addressed, such as in-stent restenosis (ISR) and late thrombosis. Many modified stents have been developed to inhibit the hyperproliferation of vascular smooth muscle cells (SMCs) and protect vascular endothelial cells (VECs), thereby reducing such complications. Some modified stents, such as those infused with rapamycin, have improved in preventing acute thrombosis. However, ISR and late thrombosis, which are long-term complications, remain unavoidable. Panax notoginseng saponin (PNS), a traditional Chinese medicine consisting of various compounds, is beneficial in promoting the proliferation and migration of VECs and inhibiting the proliferation of SMCs. Herein, a 3D-printed polycaprolactone (PCL) stent loaded with PNS (PNS-PCL stent) was developed based on a previous study. In vitro studies confirmed that PNS promotes the migration and proliferation of VECs, which were damaged, by increasing the expression levels of microRNA-126, p-AKT, and endothelial nitric oxide synthase. In vivo, the PNS-PCL stents maintained the patency of the carotid artery in rabbits for up to three months, outperforming the PCL stents. The PNS-PCL stents may present a new solution for the EVT of cerebrovascular atherosclerotic stenosis in the future.

Inspired by the unidirectional liquid spreading on Nepenthes peristome, Araucaria leaf, butterfly wings, etc., various microfluidic devices have been developed for water collection, irrigation, physical/chemical reaction, and oil-water separation. Despite extensive progress, most natural and artificial structures fail to enhance the Laplace pressure difference or capillary force, thus suffering from a low unidirectional capillary height (<30 mm). In this work, asymmetric re-entrant structures with long overhangs and connected forward/lateral microchannels are fabricated by 3D printing, resulting in a significantly increased unidirectional capillary height of 102.3 mm for water, which approximately corresponds to the theoretical limit. The overhangs can partially overlap the forward microchannels of the front structures without direct contact, thus enhancing the Laplace pressure difference and capillary force simultaneously. Based on asymmetric and symmetric re-entrant structures, capillary transistors are proposed and realized to programmably adjust the capillary direction, height, and width, which are envisioned to function as switches/valves and amplifiers/attenuators for highly efficient liquid patterning, desalination, and biochemical microreaction in 3D space.

OBJECTIVE: To assess the effect of nanoglass (NG) particles and multiwalled carbon nanotubes\' (MWCNTs) addition on Vickers hardness (VH), degree of conversion (DC), and abrasion resistance of 3D-printed denture base resin.
METHODS: 3D-printed denture base resin was reinforced using silanized NG and MWCNTs to obtain four groups: Control, 0.25 wt% NG reinforced resin, 0.25 wt% MWCNTs reinforced resin, and a combination group of 0.25 wt% of both fillers. All specimens (N = 176) were tested before and after thermal aging (600 cycles) for VH (n = 22), DC, and abrasion resistance (n = 22). Abrasion resistance specimens were subjected to 60,000 brushing strokes, and then assessed for surface roughness (Ra) and weight loss. Specimens were then scanned with a benchtop scanner before and after abrasion to produce a color map of topographical changes from superimposed images. Data were analyzed using ANOVA tests followed by Tukey post hoc test. Kruskal-Wallis test was used to compare percent change among groups, followed by Dunn post hoc test (α = 0.05).
RESULTS: The interaction between nanofiller content and thermal cycling displayed a significant effect on VH and DC. The 0.25% NG expressed the highest VH before aging but revealed the highest percent decrease after aging. Nanofiller content, thermal aging, and brushing displayed a significant interaction impact on the Ra values.
CONCLUSIONS: The addition of nanofillers resulted in an overall improvement in resin microhardness and abrasion resistance. The 0.25% MWCNTs group revealed the lowest Ra with the least percent change in VH and DC, while the combination one displayed the least change in weight.

This research analyzed the effect of the manufacturing method on the flexural strength and color stability of 3D-printed resins used for producing indirect restorations. For this, two dental restorative biocompatible resin materials, OnX (OnX, SprintRay) and CB (Crown and Bridge, Dentca), were divided into 2 groups according with manufacturing method (printed with a Pro95 3D printer - SprintRay; and not printed, with samples obtained with the fluid resin being poured on PVS molds for further light activation in the post-curing process), and subdivided into 2 groups according to the post-curing method: VG (Valo Grand, Ultradent Products) for 120 s and PC (Procure 2, SprintRay). Bar-shaped samples were used to evaluate the flexural strength 24 h after storage in distilled water at 37 °C using a universal testing machine. Disk-shaped samples were used to evaluate the color stability with a spectrophotometer at baseline, after 1-7 days in dark dry storage at 37 °C, and after 1 day of artificial aging in water at 60 °C. Data were evaluated using 3-way ANOVA (flexural strength) and 4-way repeated measures ANOVA (color stability), followed by the Tukey\'s HSD test (α = .05). Flexural strength showed significant results for resin (p < .001), while manufacturing and post-curing methods were not significant (p > .05). The interaction effects between resin and manufacturing method (p = .978), and between resin, manufacturing method and post-curing method (p = .659) were not significant. In general, OnX showed higher flexural strength values than CB, regardless of manufacturing method or post-curing protocol. Color stability results showed significant results for resin (p < .001), time (p < .001), resin and time (p = .029), and resin and curing method (p < .001), but no differences considering resin and manufacturing mode (p = .87), or resin, manufacturing method and curing method (p = .35). In general, OnX showed a higher color change than CB, longer storage times resulted in increased color change for both materials, and CB cured with VG showed lower color alteration than CB cured with PC2. The manufacturing method (3D printed or not 3D printed) does not seem to influence the flexural strength and color stability of 3D printed resins. This may indicate that, at least from a physical-mechanical perspective, the final properties of the material are mainly dependent on the post-curing process.

Consumers have become more conscious of their diet, resulting in an increased demand for low-calorie and nutrient-rich food. Therefore, finding alternative ways to develop food products with improved nutritional values has become necessary without compromising the textural and sensorial properties. In the last few years, emulsion gels have gained much popularity for oil structuring, delivery of bioactive compounds, and development of nutritious food products. Protein-stabilized emulsion hydrogels have the most significant potential to be utilized in the food industry as they contain natural ingredients that help with clean label tags. Different gelation methods can be used to fabricate emulsion gels depending on the requirements of end products. Emulsion hydrogels\' rheological, textural, mechanical, and structural properties can be modified by altering their composition, oil concentration, gelation method, and gelling environment, such as pH, temperature, etc. This review addresses using protein-based emulsion gels to develop novel food products with reduced-calorie and nutrition-rich content.