HILITE – Ion Trap for Studies with Intense Laser Pulses

Synopsis We present our Penning Trap setup which is designed for capture, confinement and preparation of well-defined ion clouds for use in experiments with high-intensity lasers. We explain the experimental setup and the techniques used to capture, confine, manipulate and detect the ions inside the Penning trap. We give an over-view of the status of the project and the planned procedures to measure the laser-focus shape in situ

Treatment of Auditory Processing in Noise in Individuals With Mild Aphasia: Pilot Study

Purpose: Listening in noise challenges listeners with auditory comprehension impairments in aphasia. We examined the effects of Trivia Game, a computerized program with questions spoken in increasing levels of background noise with success in the game. Methods: We piloted Trivia Game in four individuals with chronic aphasia and mild auditory comprehension impairments. Participants played Trivia Game for 12 twenty-minute sessions. In addition to the Western Aphasia Battery (WAB), we measured outcomes on Quick Speech in Noise (QSIN), a sentence repetition test, administered in auditory (AUD) and auditory+visual (AV) conditions as signal-to-noise ratio varied from 25 to 0 dB. Results: All four participants showed progress within the game in the noise level attained. Increases in repetition accuracy were seen in two participants for the QSIN AUD condition (average of 5.5 words), and in three participants for QSIN AV (average of 16.5 words). One individual increased performance on the WAB. Conclusions: Use of Trivia Game led to improved auditory processing abilities in all four individuals with aphasia. Greater gains noted in the AV condition over AUD suggest that Trivia Game may facilitate speech-reading skills to support comprehension of speech in situations with background noise

Enhancing Preservice Teachers\u27 Intention to Integrate Engineering Through a Multi-Disciplinary Partnership (Evaluation)

Driven by the need to broaden participation and increase recruitment in STEM fields, considerable efforts are underway to promote the infusion of engineering into elementary and secondary grade levels. The benefits of engineering education and the strong support from professional and educational groups are well documented, yet the actual integration of engineering content in the K-12 setting remains a challenge. Pre-college educator programs that train future teachers are a natural target for the integration efforts. Although elementary educators recognize the importance of integrating engineering in their classrooms, they often lack the confidence to teach engineering content. The absence of effective engineering instruction in teacher preparation programs leaves future educators unprepared for this challenge. Ed+gineering is an NSF-funded partnership between education and engineering students and faculty aimed at increasing preservice teacher (PST) preparation, confidence, and intention to integrate engineering into their teaching. The project partners education and engineering students at three points in their professional preparation within the context of their respective university courses. As part of their coursework, small cross-disciplinary teams plan and deliver culturally responsive engineering lessons to elementary school students. This paper investigates the impact of Ed+gineering on PSTs’ knowledge of engineering practices, self-efficacy to integrate engineering, pedagogical knowledge, beliefs about engineering integration, and engineering pedagogy. ANCOVA analysis was used to assess the impact of Ed+gineering on participating PSTs. Data was collected from three collaborations involving students in engineering and education during Spring 2020. A validated survey was used to assess the variables of interest. Preliminary results suggest that the Ed+gineering partnership had a positive impact on engineering pedagogical knowledge, general pedagogical knowledge, knowledge of engineering practices, and self-efficacy for integrating engineering. The specific magnitude of the impact and its implications will be discussed in this paper

Undergraduate Engineering and Education Students Reflect on Their Interdisciplinary Teamwork Experiences Following Transition to Virtual Instruction Caused by COVID-19

This study explores undergraduate engineering and education students’ perspectives on their interdisciplinary teams throughout the rapid transition to online learning and instruction from a face-to-face to a virtual format. In this qualitative study, students’ reflections and focus groups from three interdisciplinary collaborations were analyzed using the lens of Social Cognitive Theory. COVID-19 created a dramatic change in the environment such that the most immediate and direct impact on students’ experiences was on the environmental aspects of Bandura’s triadic reciprocal determinism model, which then triggered behavioral and personal responses to adapt to the new environment. Subsequent evidence of reciprocal effects between environmental, behavioral, and personal factors took place as students continued to adapt. Results suggest that the modifications made to transition the project fully online were meaningful experiences for students’ learning and teaching of engineering through teams. This interdisciplinary partnership provided both pre-service teachers and undergraduate engineering students with the opportunity to learn and practice content and professional skills that will be essential for success in future work environments

Local growth of CuInSe2 micro solar cells for concentrator application

A procedure to fabricate CuInSe2 CISe micro absorbers and solar cells for concentrator applications is presented. The micro absorbers are developed from indium precursor islands, which are deposited on a molybdenum coated glass substrate back contact , followed by deposition of copper on top and subsequent selenization as well as selective etching of copper selenides. In order to compare the properties of the locally grown absorbers to those of conventional large area CISe films, we systematically examine the compositional and morphological homogeneity of the micro absorbers and carry out photoluminescence measurements. Preliminary devices for micro concentrator solar cell applications are fabricated by optimizing the copper to indium ratio and the size of the indium precursor islands. The resulting micro solar cells provide a characteristic I V curve under standard illumination conditions 1 su

Regularly arranged indium islands on glass/molybdenum substrates upon femtosecond laser and physical vapor deposition processing

A bottom-up approach is presented for the production of arrays of indium islands on a molybdenum layer on glass, which can serve as micro-sized precursors for indium compounds such as copper-indium-gallium-diselenide used in photovoltaics. Femtosecond laser ablation of glass and a subsequent deposition of a molybdenumfilm or direct laser processing of the molybdenumfilm both allow the preferential nucleation and growth of indium islands at the predefined locations in a following indium-based physical vapor deposition(PVD) process. A proper choice of laser and deposition parameters ensures the controlled growth of indium islands exclusively at the laser ablated spots. Based on a statistical analysis, these results are compared to the non-structured molybdenumsurface, leading to randomly grown indium islands after PVD

Growth and shape of indium islands on molybdenum at micro-roughened spots created by femtosecond laser pulses

Indium islands on molybdenum coated glass can be grown in ordered arrays by surface structuring using a femtosecond laser. The effect of varying the molybdenum coated glass substrate temperature and the indium deposition rate on island areal density, volume and geometry is investigated and evaluated in a physical vapor deposition (PVD) process. The joined impact of growth conditions and spacing of the femtosecond laser structured spots on the arrangement and morphology of indium islands is demonstrated. The results yield a deeper understanding of the island growth and its precise adjustment to industrial requirements, which is indispensable for a technological application of such structures at a high throughput, for instance as precursors for the preparation of Cu(In,Ga)Se2 micro concentrator solar cells

Endovascular Treatment for Acute Isolated Internal Carotid Artery Occlusion : A Propensity Score Matched Multicenter Study.

The benefit of endovascular treatment (EVT) in patients with acute symptomatic isolated occlusion of the internal carotid artery (ICA) without involvement of the middle and anterior cerebral arteries is unclear. We aimed to compare clinical and safety outcomes of best medical treatment (BMT) versus EVT + BMT in patients with stroke due to isolated ICA occlusion. We conducted a retrospective multicenter study involving patients with isolated ICA occlusion between January 2016 and December 2020. We stratified patients by BMT versus EVT and matched the groups using propensity score matching (PSM). We assessed the effect of treatment strategy on favorable outcome (modified Rankin scale ≤ 2) 90 days after treatment and compared reduction in NIHSS score at discharge, rates of symptomatic intracranial hemorrhage (sICH) and 3‑month mortality. In total, we included 149 patients with isolated ICA occlusion. To address imbalances, we matched 45 patients from each group using PSM. The rate of favorable outcomes at 90 days was 56% for EVT and 38% for BMT (odds ratio, OR 1.89, 95% confidence interval, CI 0.84-4.24; p = 0.12). Patients treated with EVT showed a median reduction in NIHSS score at discharge of 6 points compared to 1 point for BMT patients (p = 0.02). Rates of symptomatic intracranial hemorrhage (7% vs. 4%; p = 0.66) and 3‑month mortality (11% vs. 13%; p = 0.74) did not differ between treatment groups. Periprocedural complications of EVT with early neurological deterioration occurred in 7% of cases. Although the benefit on functional outcome did not reach statistical significance, the results for NIHSS score improvement, and safety support the use of EVT in patients with stroke due to isolated ICA occlusion

Combined Perfusion and Permeability Imaging Reveals Different Pathophysiologic Tissue Responses After Successful Thrombectomy.

Despite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on ktrans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median ktrans elevation (IQR) of 0.77 (0.41-1.4) min-1 and was found in all 7 cases of hypoperfusion (100%), in 10 of 16 cases of hyperperfusion (63%), and in only three of 13 cases with unaffected perfusion (23%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56-0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10-0.82]) compared to hyperperfusion (PPV = 0.93 [0.68-1.0]) or unaffected perfusion (PPV = 1.0 [0.75-1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression