Direct observation of magnon-phonon coupling in yttrium iron garnet

The magnetic insulator yttrium iron garnet (YIG) with a ferrimagnetic transition temperature of $\sim$560 K has been widely used in microwave and spintronic devices. Anomalous features in the spin Seeback effect (SSE) voltages have been observed in Pt/YIG and attributed to the magnon-phonon coupling. Here we use inelastic neutron scattering to map out low-energy spin waves and acoustic phonons of YIG at 100 K as a function of increasing magnetic field. By comparing the zero and 9.1 T data, we find that instead of splitting and opening up gaps at the spin wave and acoustic phonon dispersion intersecting points, magnon-phonon coupling in YIG enhances the hybridized scattering intensity. These results are different from expectations of conventional spin-lattice coupling, calling for new paradigms to understand the scattering process of magnon-phonon interactions and the resulting magnon-polarons.Comment: 5 pages, 4 figures, PRB in pres

A high-throughput microfluidic approach for 1000-fold leukocyte reduction of platelet-rich plasma

Leukocyte reduction of donated blood products substantially reduces the risk of a number of transfusion-related complications. Current ‘leukoreduction’ filters operate by trapping leukocytes within specialized filtration material, while allowing desired blood components to pass through. However, the continuous release of inflammatory cytokines from the retained leukocytes, as well as the potential for platelet activation and clogging, are significant drawbacks of conventional ‘dead end’ filtration. To address these limitations, here we demonstrate our newly-developed ‘controlled incremental filtration’ (CIF) approach to perform high-throughput microfluidic removal of leukocytes from platelet-rich plasma (PRP) in a continuous flow regime. Leukocytes are separated from platelets within the PRP by progressively syphoning clarified PRP away from the concentrated leukocyte flowstream. Filtrate PRP collected from an optimally-designed CIF device typically showed a ~1000-fold (i.e. 99.9%) reduction in leukocyte concentration, while recovering >80% of the original platelets, at volumetric throughputs of ~1?mL/min. These results suggest that the CIF approach will enable users in many fields to now apply the advantages of microfluidic devices to particle separation, even for applications requiring macroscale flowrates

MAIDR: Making Statistical Visualizations Accessible with Multimodal Data Representation

This paper investigates new data exploration experiences that enable blind users to interact with statistical data visualizations$-$bar plots, heat maps, box plots, and scatter plots$-$leveraging multimodal data representations. In addition to sonification and textual descriptions that are commonly employed by existing accessible visualizations, our MAIDR (multimodal access and interactive data representation) system incorporates two additional modalities (braille and review) that offer complementary benefits. It also provides blind users with the autonomy and control to interactively access and understand data visualizations. In a user study involving 11 blind participants, we found the MAIDR system facilitated the accurate interpretation of statistical visualizations. Participants exhibited a range of strategies in combining multiple modalities, influenced by their past interactions and experiences with data visualizations. This work accentuates the overlooked potential of combining refreshable tactile representation with other modalities and elevates the discussion on the importance of user autonomy when designing accessible data visualizations.Comment: Accepted to CHI 2024. Source code is available at https://github.com/xability/maid

Three-dimensional canine displacement patterns in response to translation and controlled tipping retraction strategies

OBJECTIVE: To validate whether applying a well-defined initial three-dimensional (3D) load can create consistently expected tooth movement in patients. MATERIALS AND METHODS: Twenty-one patients who needed bilateral canine retraction to close extraction space were selected for this split-mouth clinical trial. After initial alignment and leveling, two canines in each patient were randomly assigned to receive either translation (TR) or controlled tipping (CT) load. The load was delivered by segmental T-loops designed to give specific initial moment/force ratios to the canines in each treatment interval (TI), verified with an orthodontic force tester. Maxillary dental casts were made before canine retraction and after each TI. The casts were digitized with a 3D laser scanner. The digital models were superimposed on the palatal rugae region. The 3D canine displacements and the displacement patterns in terms of TR, CT, and torque were calculated for each TI. RESULTS: The method can reliably detect a TR displacement greater than 0.3 mm and a rotation greater than 1.5°. Ninety-two TIs had displacements that were greater than 0.3 mm and were used for further analysis. Most displacements were oriented within ±45° from the distal direction. The displacement pattern in terms of TR or CT was not uniquely controlled by the initial moment/force ratio. CONCLUSIONS: The initial load system is not the only key factor controlling tooth movement. Using a segmental T-loop with a well-controlled load system, large variations in canine displacement can be expected clinically

The Impact of Information Explicitness and Timing on Facilitating Online Learning: A Field Experiment

Online learning systems aim to support learners’ learning process by providing various kinds of information. However, scarce research has focused on examining whether such information support can indeed foster an active learning process and ultimately achieve enhanced learning outcome. This study draws upon active learning theory, which posits that effective information support should facilitate learners’ “generation” and “reflection” process. We examined two characteristics of information support to facilitate such an active learning process, information explicitness and presentation timing (during or after a learning task). A field experiment was conducted on an online learning platform. Our findings revealed that when provided during a task, less explicit information would improve learning outcomes by encouraging generation activities. Furthermore, for learners with a stronger knowledge base, more explicit information support provided after a task assisted in the reflection process, leading to improved learning outcomes. The mechanisms were revealed by using cursor tracking technology

Hounsfield unit change in root and alveolar bone during canine retraction

INTRODUCTION: The objective of this study was to determine the Hounsfield unit (HU) changes in the alveolar bone and root surfaces during controlled canine retractions. METHODS: Eighteen maxillary canine retraction patients were selected for this split-mouth design clinical trial. The canines in each patient were randomly assigned to receive either translation or controlled tipping treatment. Pretreatment and posttreatment cone-beam computed tomography scans of each patient were used to determine tooth movement direction and HU changes. The alveolar bone and root surface were divided into 108 divisions, respectively. The HUs in each division were measured. Mixed-model analysis of variance was applied to test the HU change distribution at the P <0.05 significance level. RESULTS: The HU changes varied with the directions relative to the canine movement. The HU reductions occurred at the root surfaces. Larger reductions occurred in the divisions that were perpendicular to the moving direction. However, HUs decreased in the alveolar bone in the moving direction. The highest HU reduction was at the coronal level. CONCLUSIONS: HU reduction occurs on the root surface in the direction perpendicular to tooth movement and in the alveolar bone in the direction of tooth movement when a canine is retracted

NH3-Sensing Mechanism Using Surface Acoustic Wave Sensor with AlO(OH) Film

In this study, AlO(OH) (boehmite) film was deposited onto a surface acoustic wave (SAW) resonator using a combined sol-gel and spin-coating technology, and prepared and used as a sensitive layer for a high-performance ammonia sensor. The prepared AlO(OH) film has a mesoporous structure and a good affinity to NH3 (ammonia gas) molecules, and thus can selectively adsorb and react with NH3. When exposed to ammonia gases, the SAW sensor shows an initial positive response of the frequency shift, and then a slight decrease of the frequency responses. The sensing mechanism of the NH3 sensor is based on the competition between mass-loading and elastic-loading effects. The sensor operated at room temperature shows a positive response of 1540 Hz to 10 ppm NH3, with excellent sensitivity, selectivity and stability

Washing in hypotonic saline reduces the fraction of irreversibly-damaged cells in stored blood: a proof-of-concept study

Background During hypothermic storage, a substantial fraction of red blood cells (RBCs) transforms from flexible discocytes to rigid sphero-echinocytes and spherocytes. Infusion of these irreversibly-damaged cells into the recipient during transfusion serves no therapeutic purpose and may contribute to adverse outcomes in some patients. In this proof-of-concept study we describe the use of hypotonic washing for selective removal of the irreversibly-damaged cells from stored blood. Materials and methods Stored RBCs were mixed with saline of various concentrations to identify optimal concentration for inducing osmotic swelling and selective bursting of spherical cells (sphero-echinocytes, spherocytes), while minimising indiscriminate lysis of other RBCs. Effectiveness of optimal treatment was assessed by measuring morphology, rheological properties, and surface phosphatidylserine (PS) exposure for cells from several RBCs units (n=5, CPD>AS-1, leucoreduced, 6 weeks storage duration) washed in hypotonic vs isotonic saline. Results Washing in mildly hypotonic saline (0.585 g/dL, osmolality: 221.7±2.3 mmol/kg) reduced the fraction of spherical cells 3-fold from 9.5±3.4% to 3.2±2.8%, while cutting PS exposure in half from 1.48±0.86% to 0.59±0.29%. Isotonic washing had no effect on PS exposure or the fraction of spherical cells. Both isotonic and hypotonic washing increased the fraction of well-preserved cells (discocytes, echinocytes 1) substantially, and improved the ability of stored RBCs to perfuse an artificial microvascular network by approximately 25%, as compared with the initial sample. Discussion This study demonstrated that washing in hypotonic saline could selectively remove a significant fraction of the spherical and PS-exposing cells from stored blood, while significantly improving the rheological properties of remaining well-preserved RBCs. Further studies are needed to access the potential effect from hypotonic washing on transfusion outcomes

Low-density lipoprotein aggregation predicts adverse cardiovascular events in peripheral artery disease

Background and aims: Peripheral artery disease (PAD) is a systemic manifestation of atherosclerosis that is associated with a high risk of major adverse cardiovascular events (MACE). LDL aggregation contributes to atherosclerotic plaque progression and may contribute to plaque instability. We aimed to determine if LDL aggregation is associated with MACE in patients with PAD undergoing lower extremity revascularization (LER). Methods: Two hundred thirty-nine patients with PAD undergoing LER had blood collected at baseline and were followed prospectively for MACE (myocardial infarction, stroke, cardiovascular death) for one year. Nineteen age, sex and LDL-C-matched control subjects without cardiovascular disease also had blood drawn. Subject LDL was exposed to sphingomyelinase and LDL aggregate size measured via dynamic light scattering. Results: Mean age was 72.3 10.9 years, 32.6% were female, and LDL-cholesterol was 68 +/- 25 mg/dL. LDL aggregation was inversely associated with triglycerides, but not associated with demographics, LDL-cholesterol or other risk factors. Maximal LDL aggregation occurred significantly earlier in subjects with PAD than in control subjects. 15.9% of subjects experienced MACE over one year. The 1st tertile (shortest time to maximal aggregation) exhibited significantly higher MACE (25% vs. 12.5% in tertile 2 and 10.1% in tertile 3, p = 0.012). After multivariable adjustment for demographics and CVD risk factors, the hazard ratio for MACE in the 1st tertile was 4.57 (95% CI 1.60-13.01; p = 0.004) compared to tertile 3. Inclusion of LDL aggregation in the Framingham Heart Study risk calculator for recurrent coronary heart disease events improved the c-index from 0.57 to 0.63 (p = 0.01). Conclusions: We show that in the setting of very well controlled LDL-cholesterol, patients with PAD with the most rapid LDL aggregation had a significantly elevated MACE risk following LER even after multivariable adjustment. This measure further improved the classification specificity of an established risk prediction tool. Our findings support broader investigation of this assay for risk stratification in patients with atherosclerotic CVD.Peer reviewe