Comparative Mapping Research Articles

Validation of serum paraoxonase/arylesterase 1 (PON1) as a protein marker of illicit dexamethasone treatment in veal calves

The illicit use of dexamethasone and other glucocorticoids for cattle fattening in livestock production has been widely described; evidence for illegal treatments can be obtained by direct or indirect detection. In our previous study, we applied two-dimensional electrophoresis (2DE) to identify plasma protein markers of dexamethasone administration in veal calves. Comparison of 2DE maps obtained from blood samples before and after treatment showed the disappearance of two protein spots identified as serum paraoxonase/arylesterase 1 precursor (PON1). In the present study, we validated PON1 as a marker by analysing a larger number of samples treated with dexamethasone for illicit use. Analysis of samples from experimental treatment with other glucocorticoids, androgens and oestrogens confirmed that their influence on PON1 could be excluded. The specificity of the PON1 protein marker was verified on expected negative field samples to exclude interfering factors. However, there is poor statistical evidence to support a significant association between the outcome of PON1 and the considered variables. The results on field samples were compared with histological examination of the thymus as a biomarker of corticosteroid treatment monitored in the Italian histological plan for the control of growth promoters in animals. Two suspect cases were identified from two Piedmont farms where other animals had tested positive at histological examination. In conclusion, the absence of PON1 in the plasma of veal calves can indirectly reveal illicit dexamethasone treatment in individual animals and so identify suspect farms for further investigation. It is effective in a period ranging from 3 to about 10 days from illicit treatment, covering a time span that goes beyond the limits of official chemical controls and preceding histological controls on the thymus of slaughtered animals. PON1 detection in plasma can be coupled with other tests to identify illegal dexamethasone use on veal calf farms.

Clinical Observation of Ultrasound-Guided Nerve Block Anesthesia on Postoperative Pain Control of Fracture Patients.

To observe the postoperative pain control and clinical efficacy of ultrasound-guided nerve block anesthesia for patients with tibial fracture. A total of 128 patients with tibial fracture who received surgical treatment in our hospital from October 2020 to April 2021 were selected. The ultrasound guided anesthesia group and general anesthesia group were established by random number table method, with 64 patients in each group. Patients in the ultrasound-guided anesthesia group received ultrasound-guided nerve block anesthesia, and patients in the general anesthesia group received conventional general anesthesia. Observation times anesthetic effect in both groups, changes in hemodynamic parameters, digital pain scale (NRS) score as a result, compared two groups of patients with adverse reactions occur, change of the serum inflammatory factors indicators before and after operation, and USES the Pearson correlation coefficient analysis of the correlation between serum levels of inflammatory factor index and NRS score. The effect of anesthesia, postoperative recovery, directional force recovery, motor block and sensory block time of patients in ultrasound-guided anesthesia group decreased significantly than those in general anesthesia group (all P < 0.05). The comparison of MAP, HR and RR at T1 and T2 levels between the two groups was statistically significant (all P < 0.05). The changes of MAP, HR and RR in ultrasound guided anesthesia group were more stable than those in general anesthesia group.The NRS scores of patients in both groups showed an increasing trend with the extension of time. The 6 h, 12 h and 24 hNRS scores of patients in the ultrasound guided anesthesia group decreased significantly than those in the general anesthesia group (all P < 0.05). The total incidence of adverse reactions in ultrasound guided anesthesia group decreased significantly than that in general anesthesia group (P < 0.05).The serum levels of inflammatory factor interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in 2 groups increased significantly before surgery, and the levels of each index in ultrasound guided anesthesia group decreased significantly than that in general anesthesia group (ALL P < 0.05). Pearson correlation coefficient showed that serum IL-6 and TNF-α levels were positively correlated with NRS score (all P < 0.05). Ultrasound-guided nerve block anesthesia surgery can effectively improve the tibia fracture patients intraoperative anesthetic effect, improve patients with intraoperative and postoperative hemodynamic index of stability, the anesthesia surgery will exert positive effects on patients with postoperative pain control, can reduce the risk in patients with postoperative adverse reactions, reduce the postoperative patients with inflammatory factor activity. In addition, this paper found significant positive correlation between serum inflammatory factors IL-6 and TNF-α and NRF score, suggesting that serum IL-6 and TNF-α can be monitored for postoperative pain control in patients with tibial fracture, providing reference for improving postoperative treatment plan of patients.

Transposon Insertion Drove the Loss of Natural Seed Shattering during Foxtail Millet Domestication.

Loss of seed shattering was a key step during cereal domestication, and it greatly facilitated seed harvest of the staple cereal foxtail millet (Setaria italica) because the cereal has very small seeds. However, the genetic basis for this loss has been largely unknown. Here, we combined comparative and association mapping to identify an 855-bp Harbinger transposable element insertion in the second exon of the foxtail millet gene shattering1 (sh1) that was responsible for the loss of seed shattering. The sh1 gene encodes zinc finger and YABBY domains. The insert prevents transcription of the second exon, causing partial loss of the zinc finger domain and then loss of natural seed shattering. Specifically, sh1 functions as a transcription repressor and represses the transcription of genes associated with lignin synthesis in the abscission zone, including CAD2. The diversity of sh1 is highly reduced in foxtail millet, consistent with either a severe domestication bottleneck or a selective sweep. Phylogenetic analysis of sh1 further revealed a single origin of foxtail millet in China. Our results support the theories that transposons were the most active factors in genome evolution driving loss of natural seed shattering during foxtail millet domestication and that sh1 underwent parallel selection during domestication across different cereal species.

Fraction mapping and fraction comparison skills among grade 4 Chinese students: An error analysis.

Mapping fraction symbols to magnitudes is easier for students to master than comparing fraction magnitudes. Fraction mapping assesses students' understanding of part-whole interpretations of fractions; fractions represent the parts of an object or set of objects. Fraction comparison assesses students' understanding of measurement interpretations of fractions; a fraction is a single numerical quantity, not a combination of two whole numbers. To examine and compare the types of errors made by emergent fraction learners on fraction mapping and comparison tasks. Grade 4 Chinese students (N=1036; 577 boys; Mage =9.9years). We examined performance and identified errors on fraction mapping and comparison tasks. For mapping, students converted pictorial representations into fraction notation. For comparison, they chose the larger of two symbolic fractions. Consistent with curriculum expectations, most students successfully mapped pictorial representations to fraction notation. In contrast, few students were able to accurately compare fraction magnitudes. Within each task, students' errors were consistent across trials, suggesting that they applied systematic but incorrect procedures. However, errors were not consistent between tasks and the correlation between mapping and comparison performance was weak. Emergent fraction learners can acquire part-whole knowledge of fractions without acquiring measurement interpretations of fractions. Moreover, misconceptions about different interpretations of fractions need not overlap. Awareness of the types of errors that students make can assist educators in identifying misconceptions early so that students do not build their fraction knowledge on erroneous beliefs.

Review of: "Multiple soil map comparison highlights challenges for predicting topsoil organic carbon concentration at national scale"

Review of: "Multiple soil map comparison highlights challenges for predicting topsoil organic carbon concentration at national scale"

Indoor Localization of Hand-Held OCT Probe Using Visual Odometry and Real-Time Segmentation Using Deep Learning.

Optical coherence tomography (OCT) is an established medical imaging modality that has found widespread use due to its ability to visualize tissue structures at a high resolution. Currently, OCT hand-held imaging probes lack positional information, making it difficult or even impossible to link a specific image to the location it was originally obtained. In this study, we propose a camera-based localization method to track and record the scanner position in real-time, as well as providing a deep learning-based segmentation method. We used camera-based visual odometry (VO) and simultaneous mapping and localization (SLAM) to compute and visualize the location of a hand-held OCT imaging probe. A deep convolutional neural network (CNN) was used for kidney tubule lumens segmentation. The mean absolute error (MAE) and the standard deviation (STD) for 1D translation were found to be 0.15 mm and 0.26mm respectively. For 2D translation, the MAE and STD were found to be 0.85 mm and 0.50 mm, respectively. The dice coefficient of the segmentation method was 0.7. The t-statistic of the T-test between predicted and actual average densities and predicted and actual average diameters were 7.7547e-13 and 2.2288e-15 respectively. We also experimented on a preserved kidney utilizing our localization method with automatic segmentation. Comparisons of the average density maps and average diameter maps were made between the 3D comprehensive scan and VO system scan. Our results demonstrate that VO can track the probe location at high accuracy, and provides a user-friendly visualization tool to review OCT 2D images in 3D space. It also indicates that deep learning can provide high accuracy and high speed for segmentation. The proposed methods can be potentially used to predict delayed graft function (DGF) in kidney transplantation.

A 3D molecular map of the cavefish neural plate illuminates eye-field organization and its borders in vertebrates.

The vertebrate retinas originate from a specific anlage in the anterior neural plate called the eye field. Its identity is conferred by a set of 'eye transcription factors', whose combinatorial expression has been overlooked. Here, we use the dimorphic teleost Astyanax mexicanus, which develops proper eyes in the wild type and smaller colobomatous eyes in the blind cavefish embryos, to unravel the molecular anatomy of the eye field and its variations within a species. Using a series of markers (rx3, pax6a, cxcr4b, zic1, lhx2, emx3 and nkx2.1a), we draw a comparative 3D expression map at the end of gastrulation/onset of neurulation, which highlights hyper-regionalization of the eye field into sub-territories of distinct sizes, shapes, cell identities and combinatorial gene expression levels along the three body axes. All these features show significant variations in the cavefish natural mutant. We also discover sub-domains within the prospective telencephalon and characterize cell identities at the frontiers of the eye field. We propose putative fates for some of the characterized eye-field subdivisions, and suggest the existence of a trade-off between some subdivisions in the two Astyanax morphs on a micro-evolutionary scale.

SURFMAP: A Software for Mapping in Two Dimensions Protein Surface Features.

Molecular cartography using two-dimensional (2D) representation of protein surfaces has been shown to be very promising for protein surface analysis. Here, we present SURFMAP, a free standalone and easy-to-use software that enables the fast and automated 2D projection of either predefined features of protein surface (i.e., electrostatic potential, hydrophobicity, stickiness, and surface relief) or any descriptor encoded in the temperature factor column of a PDB file. SURFMAP proposes three different "equal-area" projections that have the advantage of preserving the area measures. It provides the user with (i) 2D maps that enable the easy and visual analysis of protein surface features of interest and (ii) maps in a text file format allowing the fast and straightforward quantitative comparison of 2D maps of homologous proteins.

Association Mapping of Lathyrus sativus Disease Response to Uromyces pisi Reveals Novel Loci Underlying Partial Resistance.

Uromyces pisi ([Pers.] D.C.) Wint. is an important foliar biotrophic pathogen infecting grass pea (Lathyrus sativus L.), compromising their yield stability. To date, few efforts have been made to assess the natural variation in grass pea resistance and to identify the resistance loci operating against this pathogen, limiting its efficient breeding exploitation. To overcome this knowledge gap, the genetic architecture of grass pea resistance to U. pisi was investigated using a worldwide collection of 182 accessions through a genome-wide association approach. The response of the grass pea collection to rust infection under controlled conditions and at the seedling stage did not reveal any hypersensitive response but a continuous variation for disease severity, with the identification of promising sources of partial resistance. A panel of 5,651 high-quality single-nucleotide polymorphism (SNP) markers previously generated was used to test for SNP-trait associations, based on a mixed linear model accounting for population structure. We detected seven SNP markers significantly associated with U. pisi disease severity, suggesting that partial resistance is oligogenic. Six of the associated SNP markers were located in chromosomes 4 and 6, while the remaining SNP markers had no known chromosomal position. Through comparative mapping with the pea reference genome, a total of 19 candidate genes were proposed, encoding for leucine-rich repeat, NB-ARC domain, and TGA transcription factor family, among others. Results presented in this study provided information on the availability of partial resistance in grass pea germplasm and advanced our understanding of the molecular mechanisms of quantitative resistance to rust in grass pea. Moreover, the detected associated SNP markers constitute promising genomic targets for the development of molecular tools to assist disease resistance precision breeding.

Chromosome Painting in Gymnotus carapo "Catalão" (Gymnotiformes, Teleostei): Dynamics of Chromosomal Rearrangements in Cryptic Species.

The genus Gymnotus is a large monophyletic group of freshwater weakly-electric fishes, with wide distribution in Central and South America. It has 46 valid species divided into six subgenera (Gymnotus, Tijax, Tigre, Lamontianus, Tigrinus and Pantherus) with large chromosome plasticity and diploid numbers (2n) ranging from 34 to 54. Within this rich diversity, there is controversy about whether Gymnotus (Gymnotus) carapo species is a single widespread species or a complex of cryptic species. Cytogenetic studies show different diploid numbers for G. carapo species, ranging from 40 to 54 chromosomes with varied karyotypes found even between populations sharing the same 2n. Whole chromosome painting has been used in studies on fish species and recently has been used for tracking the chromosomal evolution of Gymnotus and assisting in its cytotaxonomy. Comparative genomic mapping using chromosome painting has shown more complex rearrangements in Gymnotus carapo than shown in previous studies by classical cytogenetics. These studies demonstrate that multiple chromosome pairs are involved in its chromosomal reorganization, suggesting the presence of a complex of cryptic species due to a post zygotic barrier. In the present study, metaphase chromosomes of G. carapo occidentalis “catalão” (GCC, 2n = 40, 30m/sm+10st/a) from the Catalão Lake, Amazonas, Brazil, were hybridized with whole chromosome probes derived from the chromosomes of G. carapo (GCA, 2n = 42, 30m/sm+12st/a). The results reveal chromosome rearrangements and a high number of repetitive DNA sites. Of the 12 pairs of G. carapo chromosomes that could be individually identified (GCA 1–3, 6, 7, 9, 14, 16 and 18–21), 8 pairs (GCA 1, 2, 6, 7, 9, 14, 20, 21) had homeology conserved in GCC. Of the GCA pairs that are grouped (GCA [4, 8], [5, 17], [10, 11] and [12, 13, 15]), most kept the number of signals in GCC (GCA [5, 17], [10, 11] and [12, 13, 15]). The remaining chromosomes are rearranged in the GCC karyotype. Analysis of both populations of the G. carapo cytotypes shows extensive karyotype reorganization. Along with previous studies, this suggests that the different cytotypes analyzed here may represent different species and supports the hypothesis that G. carapo is not a single widespread species, but a group of cryptic species.

GrainGenes: Tools and Content to Assist Breeders Improving Oat Quality.

GrainGenes is the USDA-ARS database and Web resource for wheat, barley, oat, rye, and their relatives. As a community Web hub and database for small grains, GrainGenes strives to provide resources for researchers, students, and plant breeders to improve traits such as quality, yield, and disease resistance. Quantitative trait loci (QTL), genes, and genetic maps for quality attributes in GrainGenes represent the historical approach to mapping genes for groat percentage, test weight, protein, fat, and β-glucan content in oat (Avena spp.). Genetic maps are viewable in CMap, the comparative mapping tool that enables researchers to take advantage of highly populated consensus maps to increase the marker density around their genes-of-interest. GrainGenes hosts over 50 genome browsers and is launching an effort for community curation, including the manually curated tracks with beta-glucan QTL and significant markers found via GWAS and cloned cellulose synthase-like AsClF6 alleles.

Electrokinetics in two-dimensional complicated geometries: Conformal mapping and experimental comparison

By employing conformal mapping in conjunction with an experimental approach we investigate electrokinetics in two-dimensional complicated geometries, such as an eccentric annulus, concentric ellipse, and corner geometry. Conformal mapping, a powerful theoretical tool, potentially inspires future work on electrokinetics in complicated geometries, while shedding light on promising applications, including shock electrodialysis, water treatment, and electrophoresis for particle manipulation in microfluidic devices.

Comparative Mapping of World and Indian Nanocellulose Research Output during the last Decade: A Scientometric Study

Aim: The present study aims to trace out the comparative mapping of World and Indian Nanocellulose research output. Methodology: The Science Citation Index (SCI) of Web of Science (WoS) core collection was used data extraction of World and Indian Nanocellulose publications in the last ten years. The study was included the year wise research productivity of the World and India, Authorship pattern, Degree of Collaboration (DC), Collaboration Index (CI), most preferred sources, prolific authors, organizations, countries and keywords. MS excel, VOSViewer and R software package were used for tabulation and mapping. Results: A total of 3458 documents consisting of journal articles 3062, review papers 238, etc. The study reflects that Authors of multi-authored documents have more research impact with 11700 citations. The topmost preferred journal was Carbohydrate Polymers (UK) published 253 publications with a 28-h index. The most productive author was Wang X, Linkoping University, Sweden contributed 28 publications with 846 citations and h index value of 11.

Quantifying Fundamental Vegetation Traits over Europe Using the Sentinel-3 OLCI Catalogue in Google Earth Engine.

Thanks to the emergence of cloud-computing platforms and the ability of machine learning methods to solve prediction problems efficiently, this work presents a workflow to automate spatiotemporal mapping of essential vegetation traits from Sentinel-3 (S3) imagery. The traits included leaf chlorophyll content (LCC), leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FAPAR), and fractional vegetation cover (FVC), being fundamental for assessing photosynthetic activity on Earth. The workflow involved Gaussian process regression (GPR) algorithms trained on top-of-atmosphere (TOA) radiance simulations generated by the coupled canopy radiative transfer model (RTM) SCOPE and the atmospheric RTM 6SV. The retrieval models, named to S3-TOA-GPR-1.0, were directly implemented in Google Earth Engine (GEE) to enable the quantification of the traits from TOA data as acquired from the S3 Ocean and Land Colour Instrument (OLCI) sensor.Following good to high theoretical validation results with normalized root mean square error (NRMSE) ranging from 5% (FAPAR) to 19% (LAI), a three fold evaluation approach over diverse sites and land cover types was pursued: (1) temporal comparison against LAI and FAPAR products obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) for the time window 2016-2020, (2) spatial difference mapping with Copernicus Global Land Service (CGLS) estimates, and (3) direct validation using interpolated in situ data from the VALERI network. For all three approaches, promising results were achieved. Selected sites demonstrated coherent seasonal patterns compared to LAI and FAPAR MODIS products, with differences between spatially averaged temporal patterns of only 6.59%. In respect of the spatial mapping comparison, estimates provided by the S3-TOA-GPR-1.0 models indicated highest consistency with FVC and FAPAR CGLS products. Moreover, the direct validation of our S3-TOA-GPR-1.0 models against VALERI estimates indicated with regard to jurisdictional claims in good retrieval performance for LAI, FAPAR and FVC. We conclude that our retrieval workflow of spatiotemporal S3 TOA data processing into GEE opens the path towards global monitoring of fundamental vegetation traits, accessible to the whole research community.

His bundle pacing guided by automated intrinsic morphology matching is feasible in patients with narrow QRS complexes

Pace mapping and visual comparison of the local pacing response with the intrinsic QRS morphology form the mainstay of His bundle pacing (HBP). We evaluated the performance of a surface lead morphology match algorithm for automated classification of the pacing response in patients with narrow intrinsic QRS undergoing electroanatomic mapping (EAM)-guided HBP. HBP was attempted in 43 patients. In 28 cases with narrow QRS, the EnSite AutoMap Module was used for automated assessment of the QRS morphology resulting from pace mapping in the His cloud area with either a diagnostic catheter or the His lead. An intrinsic morphology match score (IMS) was calculated for 1.546 QRS complexes and assessed regarding its accuracy and performance in classifying the individual pacing response as either selective HBP (S-HBP), nonselective HBP (NS-HBP) or right ventricular stimulation. Automated morphology comparison of 354 intrinsic beats with the individual reference determined a test accuracy of 99% (95% CI 98.96–99.04) and a precision of 97.99–99.5%. For His-lead stimulation, an IMS ≥ 89% identified S-HBP with a sensitivity, specificity and positive predictive value of 1.00 (0.99, 1.00) and a negative predictive value of 0.99 (0.98, 1.00). An IMS between 78 and < 89% indicated NS-HBP with a sensitivity and specificity of 1.00 (0.99, 1.00) and 0.99 (0.98, 1.00), respectively. IMS represents a new automated measure for standardized individual morphology classification in patients with normal QRS undergoing EAM-guided HBP.Clinical trial registration: NCT04416958.

Fine mapping of Pm58 from Aegilops tauschii conferring powdery mildew resistance.

The powdery mildew resistance gene Pm58 was traced to a 141.3-kb interval with the co-segregating marker Xkasp68500 in wheat breeding. Pm58 is a powdery mildew resistance gene identified in Aegilops tauschii accession TA1662 and effective in a common wheat background. To finely map Pm58, an F2 population of 676 plants derived from the cross T093 × TA1662 was used for recombinant screening. We obtained 13 recombinants that occurred between the flanking markers Xhnu670 and Xhnu186. Genotyping and phenotyping these recombinant F2:3 families delimited Pm58 to a 0.22-cM interval (Xsts20220-Xkasp61553) on chromosome arm 2DS. The region carrying the Pm58 locus was approximately 141.3-kb, which contained eight annotated genes according to the reference genome sequence of Ae. tauschii AL8/78. Haplotype analysis of 178 Ae. tauschii accessions using the candidate gene-specific markers identified a disease resistance gene AET2Gv20068500 as a candidate for Pm58. Comparative mapping of the Pm58-containing interval revealed two presence/absence variations (PAVs) between AL8/78 and common wheat Chinese Spring. PAV-1 resides in the 3'-end of AET2Gv20068500. The majority of 158 common wheat cultivars (84.8%) displayed the absence of a 14.1-kb fragment in the PAV-1 region, which was confirmed by aligning the targeted genome sequences of the other sequenced Ae. tauschii accessions and common wheat cultivars. A co-segregating marker Xkasp68500 developed from AET2Gv20068500 can distinguish TA1662 from all randomly selected common wheat cultivars and will be instrumental for tracking Pm58 in breeding programs.

Urban and Environmental Territories Emerging from Sacred Water Sites in Edo-Tokyo

Low birth rate and increased longevity, population decline, repeated disasters, and now the spread of the novel coronavirus pandemic can all be considered issues faced by cities in the XXI century. One characteristic these problems have in common is that they require a restructuring of cities based on the following question: How do we find an appropriate scale for cities while pursuing a future wherein the urban mechanism supports society rather than the economy? A hint for the historical investigation of this question can be found in the position of sacred sites such as shrines. For example, at the time of the Great East Japan Earthquake, many cases were reported of villages' traditional shrines being located just out of the tsunami's reach, and thus avoiding damage. Over the villages' long histories, people constructed sacred sites in safe places, visualising and identifying the appropriate range for these territories based on the area's topographical characteristics and experiences of disaster. When considering the relationship between urban territories and shrines, it should be noted that sacred sites of this kind enshrined a variety of water deities. The emergence of urban and environmental territories in Edo has been elucidated by plotting water deities and sacred springs that shared a close connection to historical figures through the comparison of ancient and current maps, tracing rivers and aqueducts via a combination of topographical and geological maps, and conducting fieldwork. The significant differences between these and early XIX century shubiki maps or administrative district perimeters are proof that the traditional and environmental boundaries acknowledged since ancient times were more important for people's activities than administrative ones. The early modern city of Edo completely reconstructed sacred sites that had existed since ancient or medieval times and imbued them with new meaning. In light of this, rediscovering the historical concept of territories could provide hints on their appropriate range with a view to the solution of current problems related to population decline and disaster recovery, both in Tokyo and in other Japanese cities.

ANALISIS PENDAPATAN DAN RISIKO USAHATANI JAGUNG DI KECAMATAN METRO KIBANG KABUPATEN LAMPUNG TIMUR

This study aims to examine the comparison of income, risk, risk mapping, and risk management strategies by farmersof corn farming in dry land and rainfed land. The survey was conducted in Metro Kibang District, East Lampung Regency in January 2021. The respondents were randomly selected as many as 70 farmers consisting of 40 dry land farmers in Margototo Village and 30 rainfed land farmers in Kibang Village. The data were analyzed using the income difference test, the coefficient of variation difference test, risk mapping, and descriptive analysis of farmers’ strategies. The results showed that the income of corn farming grown in dry land and in rainfed land was different, but both were profitable. The risk of production and income of corn farming in dry land is greater than in rainfed land. The risk mapping in dry land and rainfed land shows that the highest risk source come from pests. In general, dry land farmers and rainfed land farmers have similar strategies, i.e: doing replanting and spraying pesticides for controlling pests. Key words: corn farming, income, risk, risk mapping

Comparison of Epithelial Thickness Mapping in Normal Corneas with Different Types of Astigmatism.

Corneal epithelial thickness mapping has a wide range of applications including screening for keratoconus, screening for anterior basement membrane dystrophy, and assessment of dry eye. It also plays an important role in corneal laser refractive surgery. These all require an understanding of the epithelial thickness profile in a normal cornea as a reference. This study aimed to compare corneal epithelial thickness along different meridians in normal eyes with different types of corneal astigmatism. In this cross-sectional study, corneal topography and epithelial thickness mapping by anterior segment optical coherence tomography was performed for 154 normal eyes. Corneal astigmatism was classified based on the orientation of the steepest corneal meridian (with-the-rule [WTR], against-the-rule [ATR], and oblique) and the amount (low, moderate, and high). On a 9-mm epithelial thickness map, the thickness along the horizontal (180°), vertical (90°), and diagonal (45 and 135°) meridians was calculated. With-the-rule, oblique, and ATR astigmatisms were observed in 40, 31, and 29% of the eyes, respectively. In all types of astigmatism, the mean epithelial thickness was greater along the 180° meridian and thinner along the 90° meridian. There was no statistically significant difference in mean thickness along different meridians for WTR (P = .24) and oblique (P = .46) astigmatism, whereas the difference along the 180 and 90° meridians (P = .003) for ATR astigmatism was statistically significant. Also, there was a statistically significant difference in thickness in different types of astigmatism separately for each meridian (P < .05) so that the highest and lowest thicknesses were seen for ATR and oblique astigmatisms, respectively. The epithelial thickness showed no statistical difference in various amounts of astigmatism along different meridians. Thicker epithelium along the horizontal meridian in ATR may point to the surface regularizing functions of the epithelium to create a regular and smooth surface, but thickness assessment along the different meridians in oblique and WTR showed no curvature-dependent changes.

RAY-POS: a LIDAR-based assistance system for intraoperative repositioning of mobile C-arms without external aids

PurposeIn current clinical practice, intraoperative repositioning of mobile C-arms is challenging due to a lack of visual cues and efficient guiding tools. This can be detrimental to the surgical workflow and lead to additional radiation burdens for both patient and personnel. To overcome this problem, we present our novel approach Lidar-based X-ray Positioning for Mobile C-arms (RAY-POS) for assisting circulating nurses during intraoperative C-arm repositioning without requiring external aids.MethodsRAY-POS consists of a localization module and a graphical user interface for guiding the user back to a previously recorded C-Arm position. We conducted a systematic comparison of simultaneous localization and mapping (SLAM) algorithms using different attachment positions of light detection and ranging (LIDAR) sensors to benchmark localization performance within the operating room (OR). For two promising combinations, we conducted further end-to-end repositioning tests within a realistic OR setup.ResultsSLAM algorithm gmapping with a LIDAR sensor mounted 40 cm above the C-arm’s horizontal unit performed best regarding localization accuracy and long-term stability. The distribution of the repositioning error yielded an effective standard deviation of 7.61 mm.ConclusionWe conclude that a proof-of-concept for LIDAR-based C-arm repositioning without external aids has been achieved. In future work, we mainly aim at extending the capabilities of our system and evaluating the usability together with clinicians.