Search Results (171)

Quantum cascade lasers (QCLs) are important laser sources in the mid-infrared band. Among them, single-mode quantum cascade lasers show significant advantages in key performance such as output wavelength stability and narrow linewidth. These lasers have broad application prospects in fields such as gas detection, component analysis, and medical diagnosis. Single-mode quantum cascade lasers are mainly achieved through distributed feedback (DFB) gratings and distributed Bragg reflector (DBR) gratings. This paper presents the basic principles of quantum cascade lasers and summarizes the research progress of distributed feedback quantum cascade lasers and distributed Bragg reflector quantum cascade lasers in recent years, respectively. Finally, an in-depth discussion and outlook on the development direction and research trends of single-mode quantum cascade lasers are presented. Full article

This paper presents a qualitative case study on the design, implementation, and validation of the Art Nouveau Path, a mobile augmented reality game developed to foster sustainability competences through engagement with Aveiro’s Art Nouveau built heritage. Grounded in the GreenComp framework and developed through a Design-Based Research approach, the game integrates location-based interaction, narrative storytelling, and multimodal augmented reality and multimedia content to activate key competences such as systems thinking, futures literacy, and sustainability-oriented action. The game was validated with 33 in-service schoolteachers, both through a simulation-based training workshop and a curricular review of the game. A mixed-methods strategy was used, combining structured questionnaires, open-ended reflections, and curricular review. The findings revealed strong emotional and motivational engagement, interdisciplinary relevance, and alignment with formal education goals. Teachers emphasized the game’s capacity to connect local identity with global sustainability challenges through immersive and reflective experiences. Limitations pointed to the need for enhanced pedagogical scaffolding, clearer integration into STEAM subjects, and broader accessibility across technological contexts. This study demonstrates that these games, when grounded in competence-based frameworks and inclusive design, can meaningfully support multimodal, situated learning for sustainability and offer valuable contributions to pedagogical innovation in Education for Sustainable Development. Full article

This conceptual paper presents a framework for supporting multilingual students’ mathematical discourse through teacher professional development grounded in design-based research (DBR). Drawing on sociocultural learning theory, the Integrated Language and Mathematics Project (ILMP) was co-developed with elementary educators to promote integrated instruction that simultaneously advances students’ mathematical understanding, language development, and cultural identity. The ILMP framework centers around three instructional pillars: attention to language, attention to mathematical thinking, and cultural responsiveness. Through collaborative inquiry cycles, educators engaged as learners, contributors, and designers of practice, iteratively enacting and reflecting on instructional strategies rooted in students’ linguistic and cultural assets. Teachers implemented discussion-rich mathematical tasks, supported by language scaffolds and culturally relevant contexts, to foster students’ mathematical reasoning and communication. This approach was particularly impactful for multilingual learners, whose language use and problem-solving strategies were both valued and elevated. This paper also discusses the opportunities and challenges of DBR and research–practice partnerships, including flexibility in implementation and navigating district-level priorities. Insights underscore the importance of practitioner agency, asset-based pedagogy, and the co-construction of professional learning. The ILMP framework offers a scalable, equity-oriented model for improving integrated language and mathematics instruction in diverse elementary classrooms and beyond. Full article

Dinder Biosphere Reserve (DBR), a UNESCO-recognized biodiversity hotspot in Sudan, faces escalating land-use pressure. We analyzed land cover changes from 2019 to 2024 using Sentinel-2 imagery processed in Google Earth Engine. A Random Forest classifier identified five land cover classes: water, built-up areas, vegetation, bare land, and crops. The transition matrix revealed significant changes over this period. About 1501 km² of vegetation and 1648 km² of cropland were converted to bare land. Built-up areas lost 95 km² to bare land. Bare land remained largely unchanged (4749 km²), while water bodies were the most stable (13,473 km² unchanged). Only minor transitions involved water (27.6 km² to vegetation, 15.2 km² to bare land). Notably, 411 km² of cropland and 1773 km² of bare land transitioned to vegetation, indicating some regrowth. These land cover changes reflect a dynamic interplay between degradation and recovery processes; however, the results should be interpreted with caution due to potential classification inaccuracies, seasonal variation in imagery, and absence of field validation. Continued satellite monitoring is essential to guide adaptive land management and safeguard ecosystem function in DBR. Full article

Background and Objectives: Breast reconstruction following mastectomy improves quality of life and psychosocial outcomes, yet it is not consistently performed despite multiple federal mandates. Current data shows decreased reconstruction in minority races, those with a low socioeconomic status, and those holding public health insurance. Many barriers remain misunderstood or unstudied. This study examines barriers to post-mastectomy breast reconstruction to promote a supportive clinical climate by addressing multifactorial obstacles to equitable access to care. Materials and Methods: The California Cancer Registry Data Surveillance, Epidemiology, and End Results (SEER) database and California Health and Human Services Agency Cancer Surgeries Database (2013–2021 and 2000–2021, respectively) were used in this retrospective observational study on mastectomy with immediate breast reconstruction (IBR), delayed breast reconstruction (DBR), or mastectomy only (MO) rates. Data were collected on age, sex, race, insurance type, hospital type, socioeconomic status, and residence. Pearson’s chi-square analysis was performed. Results: We found that 168,494 mastectomy and reconstruction surgeries were performed (82.36% MO, 7% IBR, 10.6% DBR). The 40–49 age group received significantly less MO (38.1%) compared to the 70–74 age group (94.8%, (p = <0.001). Significantly more reconstruction was carried out in patients with private, HMO, or PPO insurance (IBR 75.86%, DBR 75.32%, p = <0.001). Almost all breast surgeries were in urban areas as opposed to rural/isolated rural areas (96.02% vs. 1.55%, p = <0.001). There was no significant difference between races. Of all surgeries, 7.46% were completed in a cancer center with significantly higher rates of IBR. LA County, San Luis Obispo/Ventura County, and Northern CA had significantly more MO than other regions (p = <0.001). Conclusions: Reconstruction rates after mastectomy are low, with only 17.64% of patients undergoing reconstruction. Nationally, 70.5% of patients received MO, with 29.6% undergoing reconstruction. Significant factors positively contributing to reconstruction were private insurance, high SES, cancer center care, and urban residency. Identified barriers include public health insurance enrollment, rural or non-urban residence, older age, low SES, and non-white race/ethnicity, indicating potential monetary influences on care. Full article

In Industry 5.0 it is essential that humans are in the loop of technology integration of industry processes. With the advancements of Generative Artificial Intelligence (GenAI), a lot of new opportunities and challenges for learning and teaching are present. Many students already use publicly available AI Digital Assistants (p-AIDA) like ChatGPT for academic purposes. However, there are concerns around the use of such p-AIDA tools, particularly in terms of academic integrity, data privacy, intellectual property, and the impact on the quality of education. Furthermore, many higher education institutions have substantial learning materials and data about students that they may not want to share with p-AIDA. Therefore, using the Technology Acceptance Model (TAM) and following a Design-Based Research (DBR) approach, we explored the perspectives and experiences of a beta-test of an institutionally developed AIDA (i-AIDA) with 18 UK students using multiple methods and data sources (including pre-post-test, interviews, think-aloud, and prompt analysis). Our research underscores the potential benefits and limitations of in-house i-AIDA in enhancing learning experiences without compromising academic integrity or privacy, and how higher education institutions can prepare themselves for Industry 5.0. Full article

To investigate the size effect on fragmentation phenomena during hypervelocity impact, scaled experiments were conducted using a 30 mm smooth-bore ballistic range (DBR30) driven by a detonation-driven two-stage launching system. Unique stripping of sandstone target was observed, revealing that free-surface unloading waves govern peak pressure attenuation and fragmentation patterns. By establishing a shock wave attenuation model, the typical failure characteristics of different regions were distinguished, including jetting, crushing, and cracking. Parameter λ was defined to distinguish two forms of destruction, Class I (stripping-dominated) and Class II (cratering-dominated). Given the significant difference between the compressive and tensile strength of sandstone, the influence of the size effect on its failure characteristics was notable. This research also provides a valuable reference for understanding the evolution and formation mechanisms of binary asteroids. Full article

Cerebral malaria (CM) is a life-threatening disease that affects mainly children in sub-Saharan Africa. Studies have shown that children who survive CM are often left with neurological disabilities after recovery, such as behavioral changes similar to attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). However, diagnosis and treatments for ADHD are limited in many places in Africa. The purpose of this study was to assess behavioral changes following CM infection in Children in Malawi and parents’ acceptability of behavioral treatments. Twenty-one parents of children who had survived CM were compared to forty parents from the general population. Assessment instruments included the Disruptive Behavior Rating Scale (DBRS), Treatment Evaluation Inventory-Short Form (TEI-SF), and ADHD symptom checklist. The results showed that the most acceptable treatments among parents in Malawi were interrupt/redirect, discussion, and medication. Parents of CM-surviving children were significantly more accepting of medication (F(1,59) = 7.92, p < 0.007). The majority of the children who survived CM were rated above the clinical cut-off for ADHD and ODD symptoms. Full article

This study explores the use of a theatre project to enhance reading competencies among students with special educational needs (SENs) in inclusive classrooms. The project, titled “Stop Bullying! A Theatre Project”, aimed to improve students’ reading skills through dramatised engagement with texts, with a particular focus on promoting literacy and social interaction. Employing a Design-Based Research (DBR) methodology, the study involved iterative cycles of implementation and data collection. Participants, including students with varying reading abilities, engaged in theatrical activities that incorporated reading strategies such as reading aloud, paired reading, and choral reading—each designed to support comprehension, fluency, and reading confidence. Findings from multiple cycles indicated improvements in students’ social dynamics, including stronger peer interactions and increased group cohesion. While quantitative reading assessment data showed only modest gains in reading performance, qualitative observations revealed significant improvements in reading skills and social interactions during collaborative performances. The study concludes that a theatre-based approach can effectively support reading development while fostering a more inclusive and supportive classroom environment. Full article

Theory and practice related to computing education with racially/ethnically and linguistically diverse groups of preschoolers remain in nascent stages. Accordingly, early childhood educators both require substantial support when integrating culturally responsive computing into curriculum and instruction and offer valuable perspectives on emerging practices. The purpose of this research study is to explore how educator voice-directed efforts support the implementation of a culturally relevant preschool robotics program through multi-year professional development. Through qualitative analyses, we examined how educator voice, conceptualized as perspectives and participation, guided the direction of professional learning situated within a larger research-practice partnership using design-based research (DBR) methodology. By comparing voice across these sessions, we were able to identify what roles educators assumed within the partnership and how those roles shifted over time. Further, we are able to identify the structural and systemic factors that may have affected their participation and implementation. Findings show a contrast in roles across the different stages of the partnership, suggesting implications for embedding professional learning within broader partnership work as a way to cultivate educator leadership and to realize culturally responsive computing education in sustainable ways. Full article

This study investigates the mechanical and optical characteristics of silicon nitride thin films deposited with PECVD at 80 °C for tunable silicon-rich SiN_x-SiO_y-based MEMS optical cavities. Varying the deposition parameters using SiH₄ and N₂ as precursor gases for silicon-rich SiN_x thin films allows us to tune the refractive index to a value as high as 2.40 ± 0.013 at an extinction coefficient of only 0.008, an extremely low surface roughness of only 0.26 nm, and a compressive stress of about 150 MPa. We deposited 6.5-layer pairs of silicon-rich SiN_x/SiO_y-distributed Bragg reflector (DBR) micro-electro-mechanical system (MEMS) mirror that covers the whole 1300 and 1550 nm range. Cavity architectures of 6.5 top and 6 bottom layer-pairs were fabricated in the clean room providing a variety of cavity lengths between 0.615 µm and 2.85 µm. These lengths were then simulated in order to estimate the Young’s Modulus of silicon-rich SiN_x, obtaining values from 56 to 92 GPa. One of the designs was characterised electro-thermally providing a tuning range of at least 86.7 nm centred at 1585 nm. The tunable filters are well suitable for implementation as tuning element in lasers for optical coherence tomography. Full article

Artemisinin, a crucial antimalarial compound synthesized in Artemisia annua, is tightly controlled by various transcription factors. Despite significant progress in understanding this regulatory network, further exploration of additional factors is needed to improve artemisinin biosynthesis. Here, we identified a novel R2-MYB-like transcription factor, AaMYB121, which responds to methyl jasmonate (MeJA). Overexpression of AaMYB121 in transgenic A. annua plants resulted in dihydroartemisinic acid (DHAA) content being elevated 2~3 times compared to the control, while artemisinin levels increased to 1.4~2 times, significantly boosting artemisinin biosynthesis. Dual-Luciferase (Dual-LUC) assay and yeast one-hybrid (Y1H) analysis demonstrated that AaMYB121 directly binds to the promoter motifs of DBR2 (−1146~−1103) and ALDH1 (−1558~−1504), thereby triggering the transcriptional initiation of these genes. Notably, AaMYB121 features an elongated DNA-binding domain that specifically recognizes AT-rich cis-elements in the promoters of key artemisinin biosynthetic genes. These findings established AaMYB121 as a novel MYB-like transcription factor with strong potential to enhance the regulation of artemisinin production through targeted modulation, offering a valuable approach to improve artemisinin yields for therapeutic purposes. Full article

Ultrafast fiber lasers have shown exceptional performance across various domains, including material processing, medical applications, and optoelectronic communication. The semiconductor saturable absorber mirror (SESAM) is a key enabler of ultrafast laser operation. However, the narrow wavelength range and limited modulation depth of conventional SESAMs pose challenges to further advancing ultrafast fiber laser technology. To address these limitations, we explored the integration of guided mode resonance (GMR) effects to enhance light–matter interaction within the absorption layer. By incorporating subwavelength dielectric film gratings onto the cap layer of SESAMs, we excited GMR and formed a microcavity structure in conjunction with the distributed Bragg mirror (DBR). This design significantly improved the absorption efficiency of InAs quantum dots. The experimental results demonstrate that the modulation depth of the SESAM increased from 6.7% to 17.3%, while the pulse width was reduced by 2.41 times. These improvements facilitated the realization of a high-quality, stable ultrafast fiber laser. This study not only broadens the application potential of ultrafast lasers in diverse fields but also offers a practical pathway for advancing SESAM technology toward industrial-scale deployment. Full article

Currently, heritage sites, such as museums, have focused on the preservation and conservation of heritage elements for present and future generations. However, when displaying their content, they often do not consider different types of visitors, their preferences regarding the type and format of content, their interests, or their information needs (the same content is always presented). All of this can reduce the number of visits and the motivation of visitors. To address this issue, Motiv-ARCHE was developed as an application designed to enhance motivation in learning about cultural and natural heritage using augmented reality (AR). Motiv-ARCHE was implemented using the design-based research (DBR) methodology, an iterative approach that allows user feedback. In this article, we concentrate on presenting an experiment conducted at the Santa Clara Museum (Bogotá) in which a group of 44 participants used Motiv-ARCHE to access content associated with 10 cultural heritage elements that had been previously co-created with heritage experts from the museum itself. To evaluate the experiment, motivation and technology acceptance tests were applied, along with a demographic questionnaire, to statistically analyze whether the examined variables influence motivation for learning about cultural and natural heritage. Among the results, it is noteworthy that users with greater knowledge of AR, cultural and natural heritage, and a higher frequency of using this type of application felt more motivated to learn about heritage elements. Full article

Objectives: The disinfection of fabricated prostheses is crucial to prevent cross-infection between dental laboratories and clinics. However, there is a lack of information about the effects of chemical disinfection on 3D-printed denture base resins. This study aimed to evaluate the impact of different disinfectants on the flexural strength, elastic modulus, micro-hardness, surface roughness (Ra), and change in color of 3D-printed and conventional heat-polymerized (HP) denture base resins (DBRs). Methods: A total of 240 specimens (80 bar-shaped (64 × 10 × 3.3 mm) and 160 disk-shaped (10 × 2 mm)) were made from HP and 3D-printed DBRs. For each resin, the specimens were divided into four groups (n = 10) according to the disinfectant solution. One remained in water without disinfection as a control group, while the other three groups were disinfected using 1% sodium hypochlorite, 2% glutaraldehyde, or 10% Micro 10+ for 30 min. The flexural strength, elastic modulus, micro-hardness, Ra, and color change were measured. The collected data were statistically analyzed using a two-way ANOVA and Tukey’s post hoc test (α = 0.05). Results: A significant decrease in flexural strength, elastic modulus, and hardness was found with sodium hypochlorite (p < 0.05). When comparing the resins per solution, the 3D-printed resin showed a significant decrease in flexural strength, elastic modulus, and hardness compared with PMMA (p < 0.001), while no change was found in the Ra of both resins with all disinfectants (p > 0.05). Disinfecting with sodium hypochlorite resulted in a significant increase in color change for both resins (p < 0.05); however, all the changes were within clinically acceptable limits. Sodium hypochlorite showed the highest color change, while 2% glutaraldehyde and 10% Micro 10+ showed no significant changes in the tested properties (p > 0.05). Conclusions: Neither resin showed a change in surface roughness with immersion in disinfectants. Sodium hypochlorite had an adverse effect on the flexural properties, hardness, and change in color of the PMMA and 3D-printed DBRs, while the other disinfectants had no effect on the tested properties. Full article