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At least 145 records · Page 8Linked to original sources

COSIGT: population-scalable genotyping of complex loci from low-coverage sequencing data using pangenome graphs.

Pangenome graphs capture extensive structural diversity, but resolving complex loci from shallow sequencing remains challenging, particularly when samples are of low quality such as in ancient DNA. We introduce COSIGT (COsine SImilarity-based GenoTyper), which assigns diploid genotypes by matching read-depth distributions to haplotype paths via cosine similarity. Because this metric evaluates relative coverage profiles rather than absolute read counts, COSIGT substantially outperforms existing likelihood-based tools at low coverage (1-2X). We demonstrate scalability to thousands of modern and ancient genomes, enabling robust, population-scale analyses of complex variation directly from low-coverage datasets.

Humans

PLNMFG: Pseudo-label guided non-negative matrix factorization model with graph constraint for single-cell multi-omics data clustering.

The development of single-cell multi-omics sequencing technologies has enabled the simultaneous analysis of multi-omics data within the same cell. Accurate clustering of these cells is crucial for downstream analyses of complex biological functions. Despite significant advances in multi-omics integration approaches, current methodologies exhibit two major limitations. First, they inadequately incorporate prior biological knowledge from various omic layers. Second, these methods often conduct independent dimensionality reduction on individual omic datasets, thereby failing to capture the intrinsic complementary information and potentially overlooking crucial cross-platform interactions. Motivated by these, this study investigates a non-negative matrix factorization model called PLNMFG, which integrates the unified latent representation learning that retains the features between and within omics and the cluster structure learning that retains the intrinsic structure of the data into one joint framework. Specially, PLNMFG performs adaptive imputation to handle dropout events and uses prior pseudo-labels as constraints during the process of collective non-negative matrix factorization, as a result, a more robust latent representation that preserves the double similarity information is obtained. Graph Laplacian constraint is applied during clustering which further preserves structure characteristic of multi-omics data. In addition, the weight of each omic is adaptively learned based on the omic contribution. A series of experiments on 8 benchmark datasets show that our model performs well in terms of clustering accuracy and computational efficiency.

Single-Cell Analysis

Sparse spectral graph analysis and its application to gastric cancer drug resistance-specific molecular interplays identification.

Uncovering acquired drug resistance mechanisms has garnered considerable attention as drug resistance leads to treatment failure and death in patients with cancer. Although several bioinformatics studies developed various computational methodologies to uncover the drug resistance mechanisms in cancer chemotherapy, most studies were based on individual or differential gene expression analysis. However the single gene-based analysis is not enough, because perturbations in complex molecular networks are involved in anti-cancer drug resistance mechanisms. The main goal of this study is to reveal crucial molecular interplay that plays key roles in mechanism underlying acquired gastric cancer drug resistance. To uncover the mechanism and molecular characteristics of drug resistance, we propose a novel computational strategy that identified the differentially regulated gene networks. Our method measures dissimilarity of networks based on the eigenvalues of the Laplacian matrix. Especially, our strategy determined the networks' eigenstructure based on sparse eigen loadings, thus, the only crucial features to describe the graph structure are involved in the eigenanalysis without noise disturbance. We incorporated the network biology knowledge into eigenanalysis based on the network-constrained regularization. Therefore, we can achieve a biologically reliable interpretation of the differentially regulated gene network identification. Monte Carlo simulations show the outstanding performances of the proposed methodology for differentially regulated gene network identification. We applied our strategy to gastric cancer drug-resistant-specific molecular interplays and related markers. The identified drug resistance markers are verified through the literature. Our results suggest that the suppression and/or induction of COL4A1, PXDN and TGFBI and their molecular interplays enriched in the Extracellular-related pathways may provide crucial clues to enhance the chemosensitivity of gastric cancer. The developed strategy will be a useful tool to identify phenotype-specific molecular characteristics that can provide essential clues to uncover the complex cancer mechanism.

Stomach Neoplasms

[Clinical studies on rotation and translation of mandibular head in internal derangements of the temporomandibular joint with dual axis graph].

The present study was aimed at establishing the standards for functional diagnosis of the internally deranged TMJ by analyzing the rotary and gliding movements of the mandibular head. The subjects were patients with anterior displacement of the articular disc (ADD) and normal persons. The rotary movements were examined by use of a simplified condylar movement recorder and a specially developed dual axis graphic system. The findings are as follows: 1. In the patients and the normal persons as well, the rotary movements near the intercuspal contact position (ICP) showed a tendency to increase anteriorly until the mandibular head moved up to 6 mm from the ICP. However, in both patients with ADD with reduction and without reduction, the rotary movements near the ICP were significantly large as compared with those in the normal subjects. 2. In the ordinary persons, the rotary movements near the ICP were mostly larger during the closing movements than during the opening movements. In both patients with ADD with reduction and without reduction, the rotary movements were larger during the opening movement than during the closing movement. 3. The results of our study suggest that the dual axis graph could be a useful tool in examining the rotary movement of the mandibular head.

Humans

[Graph of sodium channel states].

Four models of sodium channel are considered, only one of its state being conducting. Transitions between any two communicated states are suggested to be governed by the first order kinetics. It is shown that the model describes current responses to single step potentials as well as inactivation -- activation coupling, if its graph has a function between the conducting and inactivation states and the state filled at the hyperpolarization.

Electrophysiology

[Graphs on the growth of the ice-ball using round cryoprobes at -80 degrees C and -196 degrees C (author's transl)].

Graphs and tables are shown describing the growth especially the depth of the ice-ball in tissue during freezing with round flow and massive probes (2-20 mm diameter). Thus prior to clinical application of cryosurgery the probe diameter and the time of freezing can be estimated corresponding to the size of the tumor. Results are presented for temperatures of the cooling fluid of -196 degrees C (liquid nitrogen) and -80 degrees C.

Animals

Analysis of multiscale biochemical systems: graph methods.

The applicability of usual biochemical modelling by ordinary differential equations is restricted if some of the metabolite concentrations leave the range of observability during the time span of interest. Therefore, a method is needed for testing whether the solution of a differential equation system remains comparable with given reference concentrations, which depend on the conditions of measurement. In the present paper, such a method based on graph theory and non-standard analysis is developed for the special case of networks of monomolecular reactions endowed with linear kinetics.

Algorithms

Value of scatter-graphs for the assessment of ECG computer measurement results.

A new method is presented, different from usual methods, for the discussion of the results of computer ECG measurement programs, based on a new graphical evaluation method. The proposed "scatter-graphs" both highlight the main program results and facilitate the comparison between various wave-recognition algorithms. They allow the distinction between the reliability of an algorithm, which is its capacity to provide a maximum of measurements with a minimum amount of errors, and its precision, i.e., the standard deviation of the differences between its point estimates and the reference. The method proves to be a powerful tool for the discussion of individual, as well as the median program results in CSE Measurement Study. It allows to highlight limitations induced in performance assessment by the variability of the reference itself, and to state that the median program is at least as close to the "Gold Standard" as the median of the referees.

Algorithms

[Paths in graphs and selection of oligonucleotide linkers].

The problem of search of an universal linker with minimal length containing all restriction endonuclease recognition sites is considered. We reduce this problem to the search of Eiler's and Hamilton's paths in graph. The use of the discrete optimization methods allows to construct the linker with the length closed to the minimum.

Base Sequence

Use of labor graphs in a community hospital.

The large series reported by Friedman have established the importance of the time factor in relation to cervical dilatation and station of the presenting part during labor. Variations of the rate of dilatation and descent may be evident using a graph with the upper values of normal. This study was conducted in a Community hospital with an average of 200 deliveries a month. The attending physician followed labor as usual, unaware of the graphic recordings. The outcome of the labors with normal and abnormal graphic patterns were compared. There was a correlation between the abnormal labor pattern, arrest of cervical dilatation, with abdominal deliveries and lower apgar scores. The recognition of abnormal labors does not require a profound understanding of labor nor the range of normalcy.

Apgar Score

The use of graphs in the ergonomic evaluation of tall pilots' sitting posture.

A survey has shown that the average height of KLM pilots has increased by 18 mm (0.7 in) per decade in the last 20 years. Around 6% are taller than 1905 mm (75.0 in), the upper limit of pilot height for flight deck design. With the use of graphs of the flight deck, we established that the main problem of tall pilots is insufficient legroom. Of all KLM/NLM aircraft types, the Boeing 747-200/300 and the Douglas DC-9 are most uncomfortable for pilots taller than 1960 mm (77.2 in). In the Airbus A310, pilots of 2000 mm (78.7 in) have insufficient legroom. The other aircraft types do not present difficulties for pilots up to 2030 mm (79.9 in). Ergonomic adaptations on the flight decks of the Boeing 747-200/300 and the Airbus A310 are necessary to alleviate the problems of tall pilots. Future aircraft types should be designed to accommodate tall pilots. If ergonomic adaptation of the flight deck is impossible, anthropometric limits for pilot selection have to be employed.

Aerospace Medicine

Variations in the gait of normal children. A graph applicable to the documentation of abnormalities.

The goal of much orthopaedic treatment of children is to improve their walking. To document the quantitative characteristics of walking, we devised graphic displays of speed, cadence, stride length, and body height on the basis of 2,416 observations of 324 children walking over a range of speeds. The gait graph is an uncomplicated tool for the clinician to use in the documentation and evaluation of gait in children. It also provides the means to relate the walking abilities of patients to the standards for normal children.

Child

Application of graph theory to analysis of Langerhans cell types on the basis of their cell nuclei ultrastructure.

Studies were performed aimed at estimating similarities and differences in ultrastructure of Langerhans cells of albino mouse epidermis. Graph theory-based analysis of surface and circumference of nucleus cross-section, heterochromatin and interchromatin area permitted to advance a view that Langerhans cells constitute a uniform cell population, as far as morphology of cell nucleus is concerned.

Animals

A straight-line graph for leg-length discrepancies.

A graphic method is presented that facilitates the recording and interpretation of data in cases of leg-length discrepancy. It provides a mechanism for predicting future growth that automatically takes into account the child's growth percentile and the degree of growth inhibition in the short leg. It can be used to predict the effects of corrective surgical procedures and to choose a surgical timetable. A series of cases of epiphyseodesis is presented, showing the straight-line graph method to be significantly more accurate than the so-called growth-remaining method, particularly in cases of growth inhibition.

Adolescent

Number of receptor sites from Scatchard and Klotz graphs: complementary approaches.

Estimates of number of receptor sites and evaluation of the complexity of the binding process require collection of a spectrum of binding measurements and selection of a theoretical model to fit the experimental data. The appropriateness of the measurements and of the model can be visually judged on graphic displays of the model-data fitting curves in Scatchard and semilogarithmic coordinates. This approach is helpful for detecting the two types of errors most frequently found in reports of binding studies: (1) underestimating the number of binding sites, and (2) failure to recognize the complexity of the binding process. While the former is readily recognizable on semilogarithmic but not on Scatchard plots of the model fitting the data, the latter might not be apparent on either plot. Collection of extensive measurements over a wide range of ligand concentrations with graphic display of the model-data fitting curves in Scatchard and semilogarithmic coordinates should be used to recognize and prevent both errors.

Humans