Analysis of InGaN Quantum Wells with AlGaInN Barriers

AbstractVarious strain-compensated InGaN-AlGaInN quantum well (QW) structures are investigated by self-consistent 6-band k∙p method, which considers valence band mixing, the strain effect, spontaneous and piezoelectric polarizations and the carrier screening effect, for their spontaneous emission and gain properties. The InGaN QW with In-content of 28% is sandwiched by AlGaInN barriers, which are Al0.2Ga0.8N, Al0.56Ga0.32In0.12N, Al0.72Ga0.13In0.15N, Al0.78Ga0.1In0.12N, and Al0.82Ga0.1In0.08N, with corresponding band gaps of 3.821eV, 4.156eV, 4.465eV, 4.765eV, and 5.065eV, respectively. Both the spontaneous emission spectra and optical gain properties of strain-compensated InGaN–AlGaInN QWs reveal enhancement in comparison to those of conventional InGaN–GN QWs. The enhancement factors of spontaneous emission spectra and peak gain properties for different barrier structures are found to follow a parabolic trend. This indicates differing amounts of improvement of the radiative efficiency for light emitting diodes. This study shows that there is an optimized composition for an AlGaInN barrier layer surrounding an In0.28Ga0.72N quantum well between the bandgaps of 4.156eV and 4.465eV that will obtain the highest spontaneous emission rate and gain properties

Thin film Gallium nitride (GaN) based acoustofluidic Tweezer: Modelling and microparticle manipulation.

Gallium nitride (GaN) is a compound semiconductor which shows advantages in new functionalities and applications due to its piezoelectric, optoelectronic, and piezo-resistive properties. This study develops a thin film GaN-based acoustic tweezer (GaNAT) using surface acoustic waves (SAWs) and demonstrates its acoustofluidic ability to pattern and manipulate microparticles. Although the piezoelectric performance of the GaNAT is compromised compared with conventional lithium niobate-based SAW devices, the inherited properties of GaN allow higher input powers and superior thermal stability. This study shows for the first time that thin film GaN is suitable for the fabrication of the acoustofluidic devices to manipulate microparticles with excellent performance. Numerical modelling of the acoustic pressure fields and the trajectories of mixtures of microparticles driven by the GaNAT was performed and the results were verified from the experimental studies using samples of polystyrene microspheres. The work has proved the robustness of thin film GaN as a candidate material to develop high-power acoustic tweezers, with the potential of monolithical integration with electronics to offer diverse microsystem applications.Engineering and Physical Sciences Research Council Grant numbers: EP/P002803/1, EP/P018998/1, Natural Science Basic Research Program of Shaanxi Province/2020JQ-233, Fundamental Scientific Research of Central Universities/3102017OQD116, Engineering and Physical Sciences Research Council fellowship /EP/N01202X/2, Royal Society / IEC/NSFC/170142, IE161019, Natural Science Foundation of China/61704017, Dalian Science and Technology Innovation Fund/2018J11CY00

Molecular classification and fertility-sparing outcomes in endometrial cancer and atypical endometrial hyperplasia

Molecular classification has emerged as a critical tool for guiding personalized treatment in endometrial cancer (EC) and atypical endometrial hyperplasia (AEH). This retrospective study aimed to assess the impact of molecular classification on fertility-sparing treatment outcomes in patients diagnosed with EC and AEH who underwent fertility preservation therapy between 2006 and 2021. Patients were categorized into four molecular subtypes using immunohistochemistry (IHC) and Sanger sequencing, based on the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE): POLE-ultramutated, mismatch repair (MMR) deficient (MMRd), p53 abnormal (p53abn), and p53 wild-type (p53wt). All patients were evaluated for oncological prognosis and fertility outcomes, with a total of 103 patients included in the analysis. Recurrence rates exhibited significant differences among the molecular classifications, with the lowest recurrence rate observed in the p53wt subtype (19.7%), followed by MMRd (30.4%), POLE-ultramutated (66.7%), and p53abn (71.4%) subtypes. Multivariate Cox regression analysis indicated that the p53abn subtype was a significant risk factor for recurrence following conservation therapy when compared to the p53wt subtype. Additionally, there was a notable disparity in standard surgical treatment due to treatment failure, with operation rates of 7.5%, 19.2%, 66.7%, and 57.1% for the p53wt, MMRd, POLE-ultramutated, and p53abn subtypes, respectively. Regarding fertility outcomes, the p53wt group demonstrated the highest pregnancy rate after achieving a complete response compared to the other subtypes; however, no significant differences were observed in overall pregnancy outcomes. The ProMisE molecular classification holds significant prognostic value for patients with EC and AEH undergoing fertility-sparing treatment. Among the molecular subtypes, p53wt appears to be the most favorable for fertility-preserving interventions. This study provides essential insights into reproductive outcomes for this patient population

Power-controlled acoustofluidic manipulation of microparticles

Recently, surface acoustic wave (SAW) based acoustofluidic separation of microparticles and cells has attracted increasing interest due to accuracy and biocompatibility. Precise control of the input power of acoustofluidic devices is essential for generating optimum acoustic radiation force to manipulate microparticles given their various parameters including size, density, compressibility, and moving velocity. In this work, an acoustophoretic system is developed by employing SAW based interdigital electrode devices. Power meters are applied to closely monitor the incident and reflected powers of the SAW device, which are associated with the separation efficiency. There exists a range of input powers to migrate the microparticles to the pressure node due to their random locations when entering the SAW field. Theoretical analysis is performed to predict a proper input power to separate mixtures of polystyrene microspheres, and the end lateral position of microspheres being acoustically separated. The separation efficiency of four sizes of microspheres, including 20 µm, 15 µm, 10 µm, and 5 µm, is calculated and compared with experimental results, which suggest the input power for separating the mixture of these microspheres. The study provides a practical guidance on operating SAW devices for bioparticle separation using the incident power as a control parameter

A Reconfigurable and Portable Acoustofluidic System Based on Flexible Printed Circuit Board for the Manipulation of Microspheres

Acoustofluidic devices based on surface acoustic waves (SAWs) have been widely applied in biomedical research for the manipulation and separation of cells. In this work, we develop an accessible manufacturing process to fabricate an acoustofluidic device consisting of a SAW interdigital transducer (IDT) and a polydimethylsiloxane (PDMS) microchannel. The IDT is manufactured using a flexible printed circuit board (FPCB) pre-patterned with interdigital electrodes (IDEs) that is mechanically coupled with a piezoelectric substrate. A new microchannel moulding technique is realised by 3D printing on glass slides and is demonstrated by constructing the microchannel for the acoustofluidic device. The flexible clamping mechanism, used to construct the device, allows the reconfigurable binding between the IDT and the microchannel. This unique construction makes the acoustofluidic device capable of adjusting the angle between the microchannel and the SAW propagation, without refabrication, via either rotating the IDT or the microchannel. The angle adjustment is demonstrated by setting the polystyrene microsphere aggregation angle to -5°, 0°, 6°, and 15°. Acoustic energy density measurements demonstrate the velocity of microsphere aggregation in the device can be accurately controlled by the input power. The manufacturing process has the advantages of reconfigurability and rapid-prototyping to facilitate preparing acoustofluidic devices for wider applications

Open source board based acoustofluidic transwells for reversible disruption of the blood–brain barrier for therapeutic delivery

Background: Blood–brain barrier (BBB) is a crucial but dynamic structure that functions as a gatekeeper for the central nervous system (CNS). Managing sufficient substances across the BBB is a major challenge, especially in the development of therapeutics for CNS disorders. Methods: To achieve an efficient, fast and safe strategy for BBB opening, an acoustofluidic transwell (AFT) was developed for reversible disruption of the BBB. The proposed AFT was consisted of a transwell insert where the BBB model was established, and a surface acoustic wave (SAW) transducer realized using open-source electronics based on printed circuit board techniques. Results: In the AFT device, the SAW produced acousto-mechanical stimulations to the BBB model resulting in decreased transendothelial electrical resistance in a dose dependent manner, indicating the disruption of the BBB. Moreover, SAW stimulation enhanced transendothelial permeability to sodium fluorescein and FITC-dextran with various molecular weight in the AFT device. Further study indicated BBB opening was mainly attributed to the apparent stretching of intercellular spaces. An in vivo study using a zebrafish model demonstrated SAW exposure promoted penetration of sodium fluorescein to the CNS. Conclusions: In summary, AFT effectively disrupts the BBB under the SAW stimulation, which is promising as a new drug delivery methodology for neurodegenerative diseases. Graphical Abstract

Thin film Gallium nitride (GaN) based acoustofluidic Tweezer: Modelling and microparticle manipulation

Gallium nitride (GaN) is a compound semiconductor which shows advantages in new functionalities and applications due to its piezoelectric, optoelectronic, and piezo-resistive properties. This study develops a thin film GaN-based acoustic tweezer (GaNAT) using surface acoustic waves (SAWs) and demonstrates its acoustofluidic ability to pattern and manipulate microparticles. Although the piezoelectric performance of the GaNAT is compromised compared with conventional lithium niobate-based SAW devices, the inherited properties of GaN allow higher input powers and superior thermal stability. This study shows for the first time that thin film GaN is suitable for the fabrication of the acoustofluidic devices to manipulate microparticles with excellent performance. Numerical modelling of the acoustic pressure fields and the trajectories of mixtures of microparticles driven by the GaNAT was performed and the results were verified from the experimental studies using samples of polystyrene microspheres. The work has proved the robustness of thin film GaN as a candidate material to develop high-power acoustic tweezers, with the potential of monolithical integration with electronics to offer diverse microsystem applications

An enhanced tilted-angle acoustic tweezer for mechanical phenotyping of cancer cells

Acoustofluidic devices becomes one of the emerging and versatile tools for many biomedical applications. Most of the previous acoustofluidic devices are used for cells manipulation, and the few devices for cell phenotyping with a limitation in throughput. In this study, an enhanced tilted-angle (ETA) acoustofluidic device is developed and applied for mechanophenotyping of live cells. The ETA Device consists of an interdigital transducer which is positioned along a microfluidic channel. An inclination angle of 5° is introduced between the interdigital transducer and the liquid flow direction. The pressure nodes formed inside the acoustofluidic field in the channel deflect the biological cells from their original course in accordance with their mechanical properties, including volume, compressibility, and density. The threshold power for fully converging the cells to the pressure node is used to calculate the acoustic contrast factor. To demonstrate the ETA device in cell mechanophenotyping, and distinguishing between different cell types, further experimentation is carried out by using A549 (lung cancer cells), MDB-MA-231 (breast cancer cells), and leukocytes. The resulting acoustic contrast factors for the lung and breast cancer cells are different from that of the leukocytes by 27.9% and 21.5%, respectively. These results suggest this methodology can successfully distinguish and phenotype different cell types based on the acoustic contrast factor

Caractérisation de revêtements de silicate de lanthane de structure apatite dopé au magnésium réalisés par projection plasma en vue d'application comme électrolyte de pile à combustible de type IT-SOFC

La pile à combustible à oxyde solide qui permet de transformer l'énergie chimique en énergie électrique, est l'une des solutions envisagées pour résoudre la crise énergétique grâce à son rendement global élevé et son fonctionnement sans aucun rejet dans l'environnement. Ces dernières années, des apatites dont la formule est La9,33+x(SiO4)6O2+3x /2 ont été développées en tant qu'électrolyte pour la pile de type SOFC fonctionnant à température intermédiaire. Il est possible d'améliorer les propriétés électriques des apatites par le dopage en site de Si4+. Parmi ces matériaux, le matériau La10Si5,8Mg0,2O26,8 présente une bonne propriété électrique. Les objectifs de cette étude sont d'étudier les processus de synthèse du matériau La10Si5,8Mg0,2O26,8 , d'utiliser ce matériau synthétisé pour élaborer par projection plasma l'électrolyte de la pile à combustible et enfin de rechercher les procédés les mieux adaptés pour préparer des cellules complètes de pile combustible de type SOFC comprenant cet électrolyte. Le matériau La10Si5.8Mg0.2O26.8 a été synthétisé à partir des poudres d'oxydes (La2O3, SiO2 et MgO) par voie solide et a été utilisé ensuite en tant que précurseur pour la projection thermique. Les paramètres de frittage ont été optimisés et une gamme de procédures a été établie pour élaborer ce matériau. La réalisation du dépôt par différents procédés de projection plasma (APS, LPPS et VLPPS) a été étudié afin les optimiser pour élaborer cet électrolyte. La recristallisation du dépôt après projection a été étudiée et un processus de traitement thermique est proposé pour obtenir des dépôts cristallisés et denses. Des cellules complètes de structure planaire avec l'électrolyte La10Si5,8Mg0,2O26,8 supporté par le cermet de Ni/Al2O3 ont été finalement élaborées par projection thermique. Les performances électriques des cellules ont été mesurées à température variant de 600C à 900C.Solid oxide fuel cell, which can transfer chemical energy into electrical energy directly, is treated as a method to solve the global energy crisis because of its high conversion efficiency and environmental friendship. In recent years, apatite-type lanthanum silicate (La9,33+x(SiO4)6O2+3x /2 ) has been developed as a electrolyte materials for the IT-SOFC. It is possible to improve the electrical properties by doping in Si4+ sites. Among these materials, La10Si5.8Mg0.2O26.8 represents good electrical property. The objective of this study is to investigate the preparation of the electrolyte La10Si5.8Mg0.2O26.8 by plasma spraying and trying to prepare the complete solid oxide fuel cell with this electrolyte. The material La10Si5.8Mg0.2O26.8 was synthesized from the oxides (La2O3, SiO2 and MgO) by the solid-state route for its use during the thermal spraying using optimized sintering parameters. The fabrication of coating La10Si5.8Mg0.2O26.8 by plasma spraying (APS, LPPS and VLPPS) was investigated to find methods of preparing the electrolyte La10Si5.8Mg0.2O26.8 of solid oxide fuel cell. The complete and planar cell with electrolyte La10Si5.8Mg0.2O26.8 supported by the Ni/Al2O3 cermet was prepared by thermal spraying. The electrical performances of cells were measured at temperatures from 600 C to 900 C.BELFORT-UTBM-SEVENANS (900942101) / SudocSudocFranceF