Scanning Approach Research Articles

High-speed three-dimensional random access scanning with a linear SLM

High-speed volumetric imaging is crucial for observing fast and distributed processes such as neuronal activity. Multiphoton microscopy helps to mitigate scattering effects inside tissue, but the standard raster scanning approach limits achievable volume rates. Random access point scanning can lead to a considerable speed-up by sampling only pre-selected locations, but existing techniques based on acousto-optic deflectors are still limited to a point rate of up to . This limits the number of parallel targets at the high acquisition rates necessary, for example, in voltage imaging or imaging of fast synaptic events. Here, we introduce SPARCLS, a method for 3D random access point scanning at up to 340 kHz using a single 1D phase modulator. We show the potential of this method by imaging synaptic events with fluorescent glutamate sensors in mammalian organotypic slices as well as in zebrafish larvae.

On tailoring of laser scan approaches for processing of a functionally graded material

ABSTRACT When it comes to machining functionally graded materials like tetragonal zirconia polycrystal-alumina, laser machining has emerged as a prominent technique, surpassing both traditional and non-traditional methods. In spite of its benefits, there are also challenges linked to laser machining of thicker substrates, primarily heat buildup, and loss of energy after many passes. In light of these difficulties, the current research investigates the relative effectiveness of short pulsed laser scan approaches in the processing of tetragonal zirconia polycrystal-alumina. A comparative investigation has been conducted between traditional laser processing and step-down laser processing of thicker tetragonal zirconia polycrystal-alumina, where the time-dependent ablation performance of short pulsed laser processing has been scrutinized with the support of experimental investigations to gain insight into the mechanism of both processes. Experimental results show that step-down laser processing outperforms the traditional laser processing by increasing ablation alongside reducing taperness. Step-down laser processing with scan track modulation effectively reduces the narrowing effect of the Gaussian beam profile by enhancing the machinability of thicker tetragonal zirconia polycrystal-alumina. This indicates its effectiveness in processing thicker substrates; which are substantial for biomedical implants.

Advanced Scanning Technology for Volume Change Measurement of Residual Soil

Weathering processes of rocks lead to the formation of residual soil layers, which are typically characterized by a deep groundwater table and a thick unsaturated zone. Hence, the calculation of a slope’s safety factor under the influences of climatic circumstances is a function of unsaturated characteristics, such as the soil–water characteristic curve (SWCC). To determine the SWCC, the volume of the soil specimen must be determined in order to compute the void ratio and degree of saturation. The drying processes of the soil specimen led to uneven soil volume change during laboratory SWCC testing, demanding the development of a soil shrinkage curve. Several methods for measuring soil volume change have been developed over the years. However, there are significant limitations, and it is rarely used due to the difficulty linked to accurately measuring the soil volume during drying processes. In this study, a revised scanning approach is developed to evaluate residual soil volume change utilizing 3D scanning technology. The proposed method is applied in a case study on residual soil from the Old Alluvium in Singapore. The laboratory data and analysis results suggested that 3D scanning technology should be required to provide a correct estimation of the air-entry value of soil.

High electromechanical coupling factor Lamb wave resonator

Lamb wave resonators (LWRs) based on lithium niobate on insulator (LNOI) substrates operating in an A1 mode at frequencies above 5 GHz typically exhibit high electromechanical coupling coefficients (K2) ranging from 20% to 30%. This makes them promising candidates to replace current bulk acoustic wave technology in next-generation broadband RF filters. However, the K2 of conventional LWRs still struggles to meet application requirements for bandwidths exceeding 1 GHz, such as WiFi-6E. This paper presents an analytical optimization approach for rapid and comprehensive scanning of the full 3D Euler space to find the maximum effective K2 of LWR devices. Such a full scan is difficult to achieve by the conventional time-consuming finite element method (FEM). The K2 results for a selected subset of Euler angles obtained through this analytical approach align with FEM simulation results. The optimized results show that LWRs on LNOI can achieve the highest K2 of 59.92% at Euler angles of (0, −151°, −60°), providing bandwidths exceeding 1 GHz at 5 GHz. To validate this optimization approach, LWRs with various orientations were fabricated on both 41° YX-cut and Z-cut LNOI wafers, with measured K2 values at different Euler angles agreeing well with both analytical and FEM results. The proposed K2 optimization method serves as a valuable guideline for selecting substrate cuts and device orientations in the design of ultra-broadband filters for next-generation telecommunications.

Dominant negative mutations in yeast Hsp90 indicate triage decision mechanism targeting client proteins for degradation.

Dominant negative mutations provide valuable tools for investigating protein mechanisms but can be difficult to isolate because of their toxic effects. We used a mutational scanning approach to identify dominant negative (DN) mutations in yeast Hsp90. In a previous mutational scan of the ATPase domain of Hsp90, we noticed that many mutations were at very low frequency after outgrowth in cells co-expressing WT Hsp90. Most of these depleted variants were located at the hinge of a lid that closes over ATP. To quantify toxic effects in the hinge regions, we performed mutational scanning using an inducible promoter and identified 113 variants with strong toxic effects. We analyzed individual DN mutations in detail and found that addition of the E33A mutation that prevents ATP hydrolysis by Hsp90 abrogated the dominant negative phenotype. FRET assays performed on individual DN mutants indicate the linkage between ATPase activity and formation of the closed structure is disrupted. DN Hsp90 decreased the expression level of two model Hsp90 clients, glucocorticoid receptor (GR) and v-src kinase. Using MG132, we found that GR was rapidly destabilized in a proteasome-dependent fashion. Biochemical analyses indicate that ATP hydrolysis by Hsp90 from open conformations can lead to ubiquitin-dependent client degradation.

Four-dimensional scanning approach to obtain surface data of the face

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Genome Dynamics of Adaptation and Introgression in Neotropical Palms

ABSTRACTAimThe combined influences of demographic dynamics and gene flow on local adaptation in plants is still poorly understood. Here, we used a genome scan approach on three closely related Neotropical palms, Acrocomia aculeata, A. intumescens and A. totai, to identify the evolutionary processes generating shared and lineage‐specific patterns of differentiation and selection across the genomic landscape.LocationAmazonia, Atlantic Forest, Cerrado and Caatinga ecoregions of Brazil.TaxaArecaceae.MethodsWe used target sequence capture and analysis of climatic correlation, detection of selective sweeps, balancing selection, and spatial and non‐spatial models to identify signatures of natural selection and admixture. We also determined temporal dynamics in spatial distribution and demographic changes.ResultsWe found a higher number of lineage‐specific than shared adaptive sites (SNPs) and no evidence of selective sweeps in shared genes, suggesting lineage specific natural selection across species. Further, evidence of balancing selection in several genes was also identified in the three species. Niche‐based and coalescent models suggest that shifts in spatial range during the Quaternary caused overlapping distributions between species, leading to hybridisation between parapatric localities.Main ConclusionsInterspecific hybridisation may have spread both neutral and adaptive SNPs, which may explain the shared adaptive genes between species. Taken together, we show how genomic adaptation can occur despite introgression, through evolutionary processes that likely drive similar patterns of adaptation in other organisms.

Characterizing disintegrated dolomite pore structure and seepage: CT scanning and numerical approach

Disintegrated dolomite slope and tunnel disasters occur frequently due to poor water stability of disintegrated dolomite, primarily in a form of seepage failure. For engineering purposes, it is critical to determine the seepage properties of disintegrated dolomite within the strata. However, conventional experimental methods are time-consuming and expensive and may not be effective in investigating seepage characteristics due to the heterogeneity of disintegrated dolomite. In this study, pore network model (PNM) was established by the computerized tomography (CT) scanning technology to characterize the pores. Meanwhile, the seepage and coefficient of permeability under different inlet stress conditions based on the accurate pore model were realized by linking the commercial image processing software Avizo with the commercial multi-physics modeling package Comsol. The results show that the porosities of severely and completely disintegrated dolomites are 29.17% and 45.37%, respectively. The grade of pore development increases with disintegration grade, which facilitates seepage failure. Severely and completely disintegrated dolomites have the coefficients of permeability of 9.67 × 10-7 m/s and 1.61 × 10-6 m/s, respectively. Under conventional conditions, severely and completely disintegrated dolomites undergo seepage failure above a pressure difference of 6 × 103 Pa and 5 × 103 Pa, respectively. These results are consistent with both in situ water pressure tests in the borehole and laboratory tests with the constant-head method, demonstrating that CT scanning is an effective method for observing fractures and pores in disintegrated dolomite for seepage evaluation.

Precise and accurate speed measurements in rapidly flowing dense suspensions

We introduce a method for precise and accurate measurements of particle speeds in dense suspensions flowing at high rates and demonstrate the utility of the approach for revealing complex flow fluctuations during shearing in a setup that combines imaging with a confocal microscope and shearing with a rheometer. We scan the focal point in one dimension, aligned with direction of flow, producing absolute measurements of speed that are independent of suspension structure and particle shape. We compare this flow-direction line scanning approach with a complementary method we introduced previously, measuring speed using line scanning in the vorticity direction. By comparing results in various flow conditions, including shear-thinning and thickening regimes, we demonstrate the efficacy of our new approach. We find that both approaches exhibit qualitatively similar flow profiles, but a comparative analysis reveals a 15%–25% overestimation in speed measurement using vorticity line scanning, with discrepancies generated by anisotropic suspension microstructure under flow. Moreover, in the thickening regime where complex flow fields are present, both approaches capture local speed fluctuations. However, line scanning in the flow direction reveals and precisely captures stagnation and backflows, a capability not achievable with vorticity line scanning. The approach introduced here not only provides a refined technique for speed measurement in fast-flowing suspensions but also emphasizes the significance of accurate measurement techniques in advancing our understanding of flow behavior in dense suspensions, particularly in contexts where strong non-affine flows are prevalent.

Assessment of the Accuracy of Two Different Scanning Approaches For The Auricular Defect

Assessment of the Accuracy of Two Different Scanning Approaches For The Auricular Defect

The Eye and Nose Identification Chip Controller-Based on Robot Vision Using Weightless Neural Network Method

Increasingly advanced image analysis in computer vision, allowing computers to interpret, identify, and analyze pictures with accuracy comparable to humans. The availability of data sources in decimal, hexadecimal, or binary forms enables researchers to take the initiative in applying their study findings. Decimal formats are typically used on traditional computers like desktops and minicomputers, whereas hexadecimal and binary formats were utilized on single-chip controllers. Weightless Neural Network is a method that can be implemented in a single chip controller. The aim of this research is to develop a facial recognition system, for eye and mouth identification, that works in a single chip controller or also called a microcontroller. The suggested method is a Weightless Neural Network with Immediate Scan approach for processing and identifying eye and nose patterns. The data will be handled in many memory locations that are specifically designed to handle massive volumes of data. The data is made up of primary face data sheets and face input data. The data sets utilized are (x,y) pixels, and frame sizes range from 90x90 pixels to 110x110 pixels. Each face shot will be processed by selecting the region of the eyes and nose and saving it as an image file. The eye and nose will identify the face frame. Next, the photos will be converted to binary format. A magazine matrix will be used to transmit binary data from a minicomputer to a microcontroller via serial connection. Based on a known pattern, the resultant similarity accuracy is 83,08% for the eye and 84,09% for the sternum. In contrast, the similarity percentage for an eye ranges from 70% to 85% for an undefined pattern.

Fabrication of microchannels on silica glass by femtosecond laser multi-scan: From surface generation mechanism to morphology control

Femtosecond laser processing has become a critical technique for the microfabrication of hard and brittle materials, particularly in microfluidic device applications. This study focuses on the fabrication of microchannels with controllable cross-sectional profiles in silica glass, a material known for its excellent physical and chemical properties. Through a combination of experimental research and theoretical analysis, the surface generation mechanisms governing microchannel morphology are investigated, alongside the influence of various processing parameters on the surface roughness at the microchannel bottom. A comprehensive optimization method is developed to control sidewall taper and surface roughness by adjusting laser scanning paths and modes. Utilizing a composite scanning approach, the study achieves near-rectangular microchannels with average sidewall taper angles below 5° and surface roughness (Sa) of 2.53 μm. These results provide a new strategy for precise control of microchannel morphology in silica glass, offering significant potential to enhance the efficiency and precision of microfluidic device fabrication, with broad applications in both industrial and research settings.

A Modified and Customized Wingsuit Flying Search (MCWFS)-based Approach for the Circular Scan Architecture

The circular scan architecture (CSA) is a widely used scan design technique in digital circuit testing that involves scanning test data through a circuit in a circular pattern. Several optimization approaches have been suggested so far to lessen the Test Data Volume (TDV), but no one has shown satisfactory results. Therefore, this paper proposes a Modified and Customized Wingsuit Flying Search algorithm to decrease the test data volume time. The proposed MCWFS-SBA-CSA introduces some novel features that distinguish it from traditional circular scan approaches. The concept of wingsuit flying is an innovative approach in the field of scan systems. This allows the scan that moves more dynamically and efficiently, enabling it to cover a larger area in a shorter time than traditional circular-scan approaches. After this phase, only scan-chosen inputs are required to obtain the next test pattern from the captured response. Therefore, required less Automatic test equipment (ATE) memory in this research so there is a Decreased cost in system-on-chip (SOC). The proposed method attains fast global searching capacity. The efficiency of the proposed technique attains 26.42%, 32.45%, and 29.34% higher compression ratio (CR), Test Application Time (TAT) reduction of SC-128 attains 29.45%, 34.67%, and 40.22% higher, TDV of SC-256 attains 32.23%, 36.34%, and 39.23% higher than existing methods, such as TDV for Circular Scan Approaches utilizing Modified Shuffled Shepard Optimization (TDV-CSA-MSSO), Effectual Very-large-scale integration Test data compression system for CSA under modified and colony metaheuristic (ETDC-CSA-MACMH), and Test Data Compression Utilizing Tetrad state Skip System (TDC-DC-TSSC) for Digital Circuits, respectively.

Hearing preservation and quality of life in small to medium sized vestibular schwannomas after a wait and scan approach or stereotactic radiosurgery: a systematic review and meta-analysis.

The management of vestibular schwannomas (VS) encompasses a choice between conservative "wait-and-scan" (WAS) approach, stereotactic radiosurgery (SRS) or open microsurgical resection. Currently, there is no consensus on the optimal management approach for small to mediumsized VS. This study aims to compared outcomes related to hearing in patients with small and mediumsized VS who underwent initial treatment with WAS versus SRS. A systematic review of the available literature was conducted using PubMed/MEDLINE, Embase, and Cochrane up December 08, 2023. Meta-analysis was performed using a random-effect model to calculate mean difference (MD) and relative risk (RR). A leave-one-out analysis was conducted. The risk of bias was assessed via the Risk of Bias in Non-randomized Studies-Interventions (ROBINS-I) and Cochrane Risk of Bias assessment tool (RoB-2). Ultimately, the certainty of evidence was evaluated using the GRADE assessment. The primary outcomes were serviceable hearing, and pure-tone average (PTA). The secondary outcome was the Penn Acoustic Neuroma Quality of Life Scale (PANQOL) total score. Nine studies were eligible for inclusion, comprising a total of 1,275 patients. Among these, 674 (52.86%) underwent WAS, while 601 patients (47.14%) received SRS. Follow-up duration ranged from two to eight years. The meta-analysis indicated that WAS had a better outcome for serviceable hearing (0.47; 95% CI: 0.32 - 0.68; p < 0.001), as well as for postoperative functional measures including PTA score (MD 13.48; 95% CI 3.83 - 23.13; p < 0.01), and PANQOL total score (MD 3.83; 95% CI 0.42 - 7.25; p = 0.03). The overall certainty of evidence ranged from "very low" to "moderate". Treating small to mediumsized VS with WAS increases the likelihood of preserving serviceable hearing and optimized PANQOL overall postoperative score compared to SRS. Nevertheless, the limited availability of literature and the methodological weakness observed in existing studies outline the need for higher-quality studies.

Revealing regional variations in scleral shear modulus in a rabbit eye model using multi-directional ultrasound optical coherence elastography

The mechanical properties of the sclera play a critical role in supporting the ocular structure and maintaining its shape. However, non-invasive measurements to quantify scleral biomechanics remain challenging. Recently introduced multi-directional optical coherence elastography (OCE) combined with an air-coupled ultrasound transducer for excitation of elastic surface waves was used to estimate phase speed and shear modulus in ex vivo rabbit globes (n = 7). The scleral phase speed (12.1 ± 3.2 m/s) was directional-dependent and higher than for corneal tissue (5.9 ± 1.4 m/s). In the tested locations, the sclera proved to be more anisotropic than the cornea by a factor of 11 in the maximum of modified planar anisotropy coefficient. The scleral shear moduli, estimated using a modified Rayleigh-Lamb wave model, showed significantly higher values in the circumferential direction (65.4 ± 31.9 kPa) than in meridional (22.5 ± 7.2 kPa); and in the anterior zone (27.3 ± 9.3 kPa) than in the posterior zone (17.8 ± 7.4 kPa). The multi-directional scanning approach allowed both quantification and radial mapping of estimated parameters within a single measurement. The results indicate that multi-directional OCE provides a valuable non-invasive assessment of scleral tissue properties that may be useful in the development of improved ocular models, the evaluation of potential myopia treatment strategies, and disease characterization and monitoring.

Finding Waldo: Sonographic systematic approach to localize the appendix in children.

To describe a systematic scanning approach using anatomical landmarks followed by an assessment of radiology trainees' ability to identify the normal appendix in healthy children. Uncontrolled pre and post study assessing radiology residents' sonographic skills in detecting the normal appendix in healthy children. Initial questionnaire for the trainees' demographics, perceptions and experiences in detecting the appendix with ultrasound in children followed by a precourse test on healthy volunteers. Hands-on training was conducted by describing a systematic sonographic approach to identify the appendix using anatomical landmarks, and then a postcourse test was carried out. The primary outcome was unprompted ability to identify the appendix. Subjective self-scoring of confidence was also recorded. A three-hour hands-on workshop was conducted. Sixteen radiology trainees participated and were randomly distributed to four stations, each with different ultrasound machines and healthy volunteers. Fifteen had a precourse assessment, and 12 completed the postcourse assessment. Before the course, 3/15 (20%) identified the appendix, while 10/12 (83%) identified the appendix afterward. After the course, participants perceived finding the appendix easier than before. There was no statistically significant difference in the participants' perceived confidence in detecting the appendix. With the described scanning technique, most of the participants were able to identify the normal appendix after receiving short hands-on training. This highlights the importance of targeted training of radiology trainees and nonradiologists.

Microwave photonics frequency scanning approach to absolute distance measurement

An absolute distance measurement approach based on microwave photonics is proposed to provide a high-resolution and non-ambiguity range measurement solution by microwave frequency scanning. The microwave interference spectrum containing optical path difference information can be generated through two rounds of intensity modulation. The approach combines the characteristics of easy focusing and collimation of light waves, as well as easy manipulation of microwaves, to achieve accurate absolute distance measurement. The experimental results show that high-precision measurements can be achieved within the frequency scanning range of only 2 GHz. The error of the distance measurement is less than ±0.079 mm. In addition, the effectiveness of the scanning pattern and the data processing algorithm are verified.

The landscape of Medicare policies for gender-affirming surgeries in Canada: an environmental scan

BackgroundMany studies have described barriers to gender-affirming surgery (GAS) in Canada; however, few have explored why these barriers persist. To address this knowledge gap, we sought to describe documents related to public health insurance (Medicare) for GAS to identify the types of procedures covered, variations in coverage across provinces and territories, and changes in policy over time.MethodsWe conducted a descriptive cross-sectional study using an environmental scan approach. We queried 23 government websites, the Google search engine, and an online legal database between July 2022 and April 2024 to gather gray literature documents related to GAS and Medicare. Variables from relevant documents were compiled to create a present, at-glance overview of GAS Medicare coverage for all provinces and territories and a timeline of policy changes across Canada. ResultsEight provinces and three territories had documents or websites related to GAS Medicare coverage (85%). We identified 15 GAS procedures that were covered variably across Canada. Yukon (n = 14) covered the most types of GAS, while Quebec and Saskatchewan covered the least (n = 6). Mastectomy and genital surgeries were covered across Canada, but other GAS were rarely covered. Five provinces and territories provided coverage for travel-related costs. Our GAS Medicare timeline showed differential expansion of GAS coverage in Canada over the last 25 years.Conclusions We provide previously unreported information regarding GAS Medicare coverage in Canada. We hope our findings will help patients and healthcare providers navigate a complicated public healthcare system. We also highlight barriers within GAS Medicare documents and make recommendations to alleviate those barriers.

Hierarchical Clustering Analysis to Inform Classification of Congenital Malformations for Surveillance of Medication Safety in Pregnancy.

There is growing interest in the secondary use of healthcare data to evaluate medication safety in pregnancy. Tree-based scan statistics (TBSS) offer an innovative approach to help identify potential safety signals. TBSS utilize hierarchically organized outcomes, generally based on existing clinical coding systems that group outcomes by organ system. When assessing teratogenicity, such groupings often lack a sound embryologic basis given the etiologic heterogeneity of congenital malformations. The study objective was to enhance the grouping of congenital malformations to be used in scanning approaches through implementation of hierarchical clustering analysis (HCA) and to pilot test an HCA-enhanced TBSS approach for medication safety surveillance in pregnancy in two test cases using >4.2 million mother-child dyads from two US-nationwide databases. HCA identified (1) malformation combinations belonging to the same organ system already grouped in existing classifications, (2) known combinations across different organ systems not previously grouped, (3) unknown combinations not previously grouped, and (4) malformations seemingly standing on their own. Testing the approach with valproate and topiramate identified expected signals, and a signal for an HCA-cluster missed by traditional classification. Augmenting existing classifications with clusters identified through large data exploration may be promising when defining phenotypes for surveillance and causal inference studies.

Ancient Pines Could Reveal the Heat of Thousands of Past Seasons

A novel 3D CT scan approach unlocks temperature records preserved in the gnarled wood of bristlecone pines.