The latest medical research on Technology

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about technology gathered by our medical AI research bot.

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The stability investigation of variable viscosity control in the human-robot interaction.

Int J Med

For many co-manipulative applications, variable damping is a valuable feature provided by robots. One approach is implementing a high viscosity at low velocities and a low viscosity at high velocities. This, however, is proven to have the possibility to alter human natural motion performance.

We show that the distortion is caused by the viscosity drop resulting in robot's resistance to motion. To address this, a method for stably achieving the desired behavior is presented. It involves leveraging a first-order linear filter to slow the viscosity variation down.

The proposition is supported by a theoretical analysis using a robotic model. Meanwhile, the user performance in human-robot experiments gets significantly improved, showing the practical efficiency in real applications.

This paper discusses the variable viscosity control in the context of co-manipulation. An instability problem and its solution were theoretically shown and experimentally evidenced through human-robot experiments. This article is protected by copyright. All rights reserved.

The assembled and annotated genome of the masked palm civet (Paguma larvata).

GigaScience

The masked palm civet (Paguma larvata) acts as an intermediate host of severe acute respiratory syndrome coronavirus (SARS-CoV), which caused SARS, and transfered this virus from bats to humans. Additionally, P. larvata has the potential to carry a variety of zoonotic viruses that may threaten human health. However, genome resources for P. larvata have not been reported to date.

A chromosome-level genome assembly of P. larvata was generated using PacBio sequencing, Illumina sequencing, and Hi-C technology. The genome assembly was 2.44 Gb in size, of which 95.32% could be grouped into 22 pseudochromosomes, with contig N50 and scaffold N50 values of 12.97 Mb and 111.81 Mb, respectively. A total of 21,582 protein-coding genes were predicted, and 95.20% of the predicted genes were functionally annotated. Phylogenetic analysis of 19 animal species confirmed the close genetic relationship between P. larvata and species belonging to the Felidae family. Gene family clustering revealed 119 unique, 243 significantly expanded, and 58 significantly contracted genes in the P. larvata genome. We identified 971 positively selected genes in P. larvata, and one known human viral receptor gene PDGFRA is positively selected in P. larvata, which is required for human cytomegalovirus infection.

This high-quality genome assembly provides a valuable genomic resource for exploring virus-host interactions. It will also provide a reliable reference for studying the genetic bases of the morphologic characteristics, adaptive evolution, and evolutionary history of this species.

AMR-meta: a k-mer and metafeature approach to classify antimicrobial resistance from high-throughput short-read metagenomics data.

GigaScience

Antimicrobial resistance (AMR) is a global health concern. High-throughput metagenomic sequencing of microbial samples enables profiling of AMR genes through comparison with curated AMR databases. However, the performance of current methods is often hampered by database incompleteness and the presence of homology/homoplasy with other non-AMR genes in sequenced samples.

We present AMR-meta, a database-free and alignment-free approach, based on k-mers, which combines algebraic matrix factorization into metafeatures with regularized regression. Metafeatures capture multi-level gene diversity across the main antibiotic classes. AMR-meta takes in reads from metagenomic shotgun sequencing and outputs predictions about whether those reads contribute to resistance against specific classes of antibiotics. In addition, AMR-meta uses an augmented training strategy that joins an AMR gene database with non-AMR genes (used as negative examples). We compare AMR-meta with AMRPlusPlus, DeepARG, and Meta-MARC, further testing their ensemble via a voting system. In cross-validation, AMR-meta has a median f-score of 0.7 (interquartile range, 0.2-0.9). On semi-synthetic metagenomic data-external test-on average AMR-meta yields a 1.3-fold hit rate increase over existing methods. In terms of run-time, AMR-meta is 3 times faster than DeepARG, 30 times faster than Meta-MARC, and as fast as AMRPlusPlus. Finally, we note that differences in AMR ontologies and observed variance of all tools in classification outputs call for further development on standardization of benchmarking data and protocols.

AMR-meta is a fast, accurate classifier that exploits non-AMR negative sets to improve sensitivity and specificity. The differences in AMR ontologies and the high variance of all tools in classification outputs call for the deployment of standard benchmarking data and protocols, to fairly compare AMR prediction tools.

Morphological parameters predicting subthreshold micropulse laser effectiveness in central serous chorioretinopathy.

Lasers in Medical Science

The purpose of this prospective study was to predict the effectiveness of subthreshold micropulse laser (SML) based on morphological parameters in patients with central serous chorioretinopathy (CSC).

Thirty-one patients were examined at presentation, 3 months, and 6 months after the disease onset. In patients with persistent subretinal fluid (SRF) at 3 months, SML was performed. The following morphological parameters were observed just before treatment: central retinal thickness (CRT), maximal SRF, choroidal thickness (CT), pigment epithelial detachment (PED) height and width, number of hyperreflective foci (HF) at fovea and leakage site, secondary choroidal neovascularization (CNV), and severity of retinal pigment epithelium (RPE) alterations using multimodal imaging.

Good response was associated with lower SRF (p = 0.038), narrower PED (p = 0.078), and decreasing number of HF at fovea (difHFf) (p = 0 .016) just before the treatment. From a bivariate and multivariate point of view, the two groups differed significantly in the pair (SRF, PED width) (p = 0.048) and in the triple (SRF, PED width, difHFf) (p = 0.026).

Lower SRF, narrower PED, and decreasing HF could be associated with good response to SML in CSC patients.

A novel virtual cutting method for deformable objects using high-order elements combined with mesh optimization.

Int J Med

Virtual cutting of deformable objects plays an important role in many applications, especially in digital medicine, such as soft tissue cutting in virtual surgery training system.

We developed a novel virtual cutting algorithm, combined with mesh optimization. A new local mesh processing method is used to control the number and quality of the elements created during the cutting process. At the same time, high-order tetrahedral elements are used to fit the cutting surface and reduce the mesh size.

In this paper, single cut, multiple cut and intersecting cut are performed on the mesh model, combined with a force feedback device, and the result obtained is that the visual feedback is higher than 30Hz, and the tactile feedback is 800∼1000Hz.

Experimental results show that the method proposed in this paper can effectively eliminate low-quality elements and control the mesh size, thereby ensuring real-time simulation. This article is protected by copyright. All rights reserved.

Retrospective Review of Secondary Prevention Strategies for Gastrointestinal Bleeding and Associated Clinical Outcomes in Left Ventricular Assist Device Patients.

Journal of Artificial Intelligence Research

Gastrointestinal bleeding (GIB) is one of the most common bleeding complications associated with Left Ventricular Assist Devices (LVAD). Currently, there is no strong evidence or clear guidance for which secondary GIB prophylaxis strategy should be implemented after the discontinuation of aspirin.

Our single-center study describes the outcomes of 26 LVAD patients who experienced a total of 49 GIB events, these individuals were either in Group-1) lower INR target range or Group-2) lower INR target plus a hemostatic agent as the secondary prophylaxis strategy. Each GIB event was considered an independent event. Outcomes assessed were bleeding reoccurrence rates, time to next GIB, acute GIB strategies, GIB-free days, thromboembolic events, survival, coagulation, and hematologic parameters.

GIB reoccurrence rates were not statistically different, Group-1) 9 (40.9%) vs Group-2) 15 (55.6%), p = 0.308. Danazol was utilized 81.5% of the time as the designated hemostatic agent. Additionally, no significant differences were observed with all of our secondary outcome measures for bleeding, ischemic events, or survival.

While our study was not powered to assess the clinical outcomes related to survival and thromboembolic events, no discernable increased risk of ischemic events including pump thrombosis was observed. Our data suggest that a lower INR target range plus danazol does not confer any additional benefit over a lower INR target range only approach. The results of this report are hypothesis-generating and additional studies are warranted to elucidate the optimal antithrombotic strategy and role of hemostatic agents in reducing the risk of recurrent GIB events.

30-day In Vivo Study of a Fully Maglev Extracorporeal Ventricular Assist Device.

Journal of Artificial Intelligence Research

Cardiogenic shock (CS) often occurs in patients suffering from rapidly progressing end-stage heart failure or acute myocardial infarction. Mechanical circulatory support may be used for patients who do not respond to medication or revascularization to stabilize hemodynamics. Extracorporeal ventricular assist device (Extra-VAD) has been reported successful for patients with cardiogenic shock. This study aimed to evaluate the 30-day in-vivo performance and safety of a newly developed Extra-VAD with maglev centrifugal pump technology, MoyoAssist®.

The study was conducted with 6 healthy ovine models, weighing 43.2~59.6 Kg). Cannulation was performed with a 34Fr venous cannula surgically connected to the left arterial appendage and a 24Fr arterial cannula inserted into descending aorta. The pump flow rate was maintained at 2 ~3 L/min to provide sufficient cardiac support without suction. Activated clotting time was maintained within the range of 150 ~ 250 s.

No device-related adverse events occurred throughout the study. Plasma-free hemoglobin results were within the acceptable range of ventricular assist device therapy (<40 mg/dL). MGS01 had an anticoagulation management related bleeding event and was terminated on day 29. All other sheep's biochemical test results were stable. The Autopsy showed no embolism or thrombus formation and no end-organ damage.

This study demonstrated that the MoyoAssist® Extra-VAD is able to provide cardiac support effectively and safely and may provide a new alternative choice for patients with CS in China.

IoT-based Mock Oxygenator for Extracorporeal Membrane Oxygenation Simulator.

Journal of Artificial Intelligence Research

Training is an essential aspect of providing high-quality treatment and ensuring patient safety in any medical practice. Because extracorporeal membrane oxygenation (ECMO) is a complicated operation with various elements, variables, and irregular situations, doctors must be experienced and knowledgeable about all conventional protocols and emergency procedures. The conventional simulation approach has a number of limitations. The approach is intrinsically costly since it relies on disposable medical equipment (i.e., oxygenators, heat exchangers, pumps) that must be replaced regularly due to the damage caused by the liquid used to simu- late blood. The oxygenator, which oxygenates the blood through a tailored membrane in ECMO, acts as a replacement for the patient's natural lung. For the context of simulation-based training (SBT) oxygenators are often expensive and cannot be recy- cled owing to contamination issues.

Consequently, it is advised that the training process include a simu- lated version of oxygenators to optimize re-usability and decrease training expenses. Toward this goal, this article demonstrates a mock oxygenator for ECMO SBT, designed to precisely replicate the real machine structure and operation.

The initial model was reproduced using 3D modeling and printing. Addi- tionally, the mock oxygenator could mimic frequent events such as pump noise and clotting. Furthermore, the oxygenator is integrated with the modular ECMO simula- tor using cloud-based communication technology that goes in hand with the internet of things (IoT) technology to provide remote control via an instructor tablet applica- tion (App).

The final 3D modeled oxygenator body was tested and integrated with the other simulation modules at Hamad Medical Corporation (HMC) with several participants to evaluate the effectiveness of the training session.

Mechanical and interventional support for heart failure with preserved ejection fraction: A review.

Journal of Artificial Intelligence Research

Restrictive cardiomyopathy (RCM) and hypertrophic cardiomyopathy (HCM) are two disease processes that are known to progress to heart failure with preserved ejection fraction (HFpEF). Pharmacologic therapies for HFpEF have not improved patient outcomes or reduced mortality in this patient cohort; thus, there continues to be substantial interest in other treatment strategies, including surgical interventions and devices. In this article, we explore and report the current utility of percutaneous therapies and surgically implanted mechanical support in the treatment of patients with HFpEF.

Treatment strategies include percutaneous interventions with interatrial shunts, left atrial assist devices (LAADs), and ventricular assist devices (VADs) in various configurations. Although VADs have been employed to treat patients with heart failure with reduced ejection fraction, their efficacy is limited in those with RCM and HCM. A left atrial-to-aortic VAD has been proposed to directly unload the left atrium, but data is limited. Alternatively, a LAAD could be placed in the mitral position and simultaneously unload the left atrium, while filling the left ventricle.

A left atrial assist device in the mitral position is a promising solution to address the hemodynamic abnormalities in RCM and HCM; these pumps, however, are still under development.

Fast and accurate estimation of multidimensional site frequency spectra from low-coverage high-throughput sequencing data.

GigaScience

The site frequency spectrum summarizes the distribution of allele frequencies throughout the genome, and it is widely used as a summary statistic to infer demographic parameters and to detect signals of natural selection. The use of high-throughput low-coverage DNA sequencing data can lead to biased estimates of the site frequency spectrum due to high levels of uncertainty in genotyping.

Here we design and implement a method to efficiently and accurately estimate the multidimensional joint site frequency spectrum for large numbers of haploid or diploid individuals across an arbitrary number of populations, using low-coverage sequencing data. The method maximizes a likelihood function that represents the probability of the sequencing data observed given a multidimensional site frequency spectrum using genotype likelihoods. Notably, it uses an advanced binning heuristic paired with an accelerated expectation-maximization algorithm for a fast and memory-efficient computation, and can generate both unfolded and folded spectra and bootstrapped replicates for haploid and diploid genomes. On the basis of extensive simulations, we show that the new method requires remarkably less storage and is faster than previous implementations whilst retaining the same accuracy. When applied to low-coverage sequencing data from the fungal pathogen Neonectria neomacrospora, results recapitulate the patterns of population differentiation generated using the original high-coverage data.

The new implementation allows for accurate estimation of population genetic parameters from arbitrarily large, low-coverage datasets, thus facilitating cost-effective sequencing experiments in model and non-model organisms.

HaploMaker: An improved algorithm for rapid haplotype assembly of genomic sequences.

GigaScience

In diploid organisms, whole-genome haplotype assembly relies on the accurate identification and assignment of heterozygous single-nucleotide polymorphism alleles to the correct homologous chromosomes. This appropriate phasing of these alleles ensures that combinations of single-nucleotide polymorphisms on any chromosome, called haplotypes, can then be used in downstream genetic analysis approaches including determining their potential association with important phenotypic traits. A number of statistical algorithms and complementary computational software tools have been developed for whole-genome haplotype construction from genomic sequence data. However, many algorithms lack the ability to phase long haplotype blocks and simultaneously achieve a competitive accuracy.

In this research we present HaploMaker, a novel reference-based haplotype assembly algorithm capable of accurately and efficiently phasing long haplotypes using paired-end short reads and longer Pacific Biosciences reads from diploid genomic sequences. To achieve this we frame the problem as a directed acyclic graph with edges weighted on read evidence and use efficient path traversal and minimization techniques to optimally phase haplotypes. We compared the HaploMaker algorithm with 3 other common reference-based haplotype assembly tools using public haplotype data of human individuals from the Platinum Genome project. With short-read sequences, the HaploMaker algorithm maintained a competitively low switch error rate across all haplotype lengths and was superior in phasing longer genomic regions. For longer Pacific Biosciences reads, the phasing accuracy of HaploMaker remained competitive for all block lengths and generated substantially longer block lengths than the competing algorithms.

HaploMaker provides an improved haplotype assembly algorithm for diploid genomic sequences by accurately phasing longer haplotypes. The computationally efficient and portable nature of the Java implementation of the algorithm will ensure that it has maximal impact in reference-sequence-based haplotype assembly applications.

A decade of GigaScience: 10 years of the evolving genomic and biomedical standards landscape.

GigaScience

Standardization of omics data drives FAIR data practices through community-built genomic data standards and biomedical ontologies. Use of standards...