21 research outputs found

    A cost-effective and universal strategy for complete prokaryotic genomic sequencing proposed by computer simulation

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    Background: Pyrosequencing techniques allow scientists to perform prokaryotic genome sequencing to achieve the draft genomic sequences within a few days. However, the assemblies with shotgun sequencing are usually composed of hundreds of contigs. A further multiplex PCR procedure is needed to fill all the gaps and link contigs into complete chromosomal sequence, which is the basis for prokaryotic comparative genomic studies. In this article, we study various pyrosequencing strategies by simulated assembling from 100 prokaryotic genomes. Findings. Simulation study shows that a single end 454 Jr. run combined with a paired end 454 Jr. run (8 kb library) can produce: 1) ∼90% of 100 assemblies with 99.99%; 4) average false gene duplication rate is < 0.7%; 5) average false gene loss rate is < 0.4%. Conclusions: A single end 454 Jr. run combined with a paired end 454 Jr. run (8 kb library) is a cost-effective way for prokaryotic whole genome sequencing. This strategy provides solution to produce high quality draft assemblies for most of prokaryotic organisms within days. Due to the small number of assembled scaffolds, the following multiplex PCR procedure (for gap filling) would be easy. As a result, large scale prokaryotic whole genome sequencing projects may be finished within weeks. © 2012 Jiang et al; BioMed Central Ltd.published_or_final_versio

    Understanding the impact of SAM Fermi levels on high efficiency p-i-n perovskite solar cells

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    Completing the picture of the underlying physics of perovskite solar cell interfaces that incorporate self-assembled molecular layers (SAMs) will accelerate further progress in p-i-n devices. In this work, we modified the Fermi level of a nickel oxide–perovskite interface by utilizing SAM layers with a range of dipole strengths to establish the link between the resulting shift of the built-in potential of the solar cell and the device parameters. To achieve this, we fabricated a series of high-efficiency perovskite solar cells with no hysteresis and characterized them through stabilize and pulse (SaP), JV curve, and time-resolved photoluminescence (TRPL) measurements. Our results unambiguously show that the potential drop across the perovskite layer (in the range of 0.6–1 V) exceeds the work function difference at the device’s electrodes. These extracted potential drop values directly correlate to work function differences in the adjacent transport layers, thus demonstrating that their Fermi level difference entirely drives the built-in potential in this device configuration. Additionally, we find that selecting a SAM with a deep HOMO level can result in charge accumulation at the interface, leading to reduced current flow. Our findings provide insights into the device physics of p-i-n perovskite solar cells, highlighting the importance of interfacial energetics on device performance

    Photoinduced Segregation Behavior in 2D Mixed Halide Perovskite: Effects of Light and Heat

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    Photoinduced halide segregation (PHS) is a process of critical importance for the performance of perovskite solar cells with mixed halide absorber layers. However, PHS is still not well understood, especially in the case of layered mixed halide perovskites (MHPs), which are less commonly studied compared to their 3D counterparts. Here, we investigated temperature- and light-induced PHS in 2D MHPs with a phenylpropylammonium (PPA) spacer. We found that 2D PPA-based MHPs exhibited complex segregation behavior dependence on temperature and illumination intensity with the suppression of segregation observed at high temperature (attributed to the highly exothermic nature of the process) as well as moderate illumination intensities, illustrating the importance of additional processes present in this particular material, which exhibits distinctly different behavior compared to 2D MHPs with other aromatic cations

    Current Applications of Deep Learning and Radiomics on CT and CBCT for Maxillofacial Diseases

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    The increasing use of computed tomography (CT) and cone beam computed tomography (CBCT) in oral and maxillofacial imaging has driven the development of deep learning and radiomics applications to assist clinicians in early diagnosis, accurate prognosis prediction, and efficient treatment planning of maxillofacial diseases. This narrative review aimed to provide an up-to-date overview of the current applications of deep learning and radiomics on CT and CBCT for the diagnosis and management of maxillofacial diseases. Based on current evidence, a wide range of deep learning models on CT/CBCT images have been developed for automatic diagnosis, segmentation, and classification of jaw cysts and tumors, cervical lymph node metastasis, salivary gland diseases, temporomandibular (TMJ) disorders, maxillary sinus pathologies, mandibular fractures, and dentomaxillofacial deformities, while CT-/CBCT-derived radiomics applications mainly focused on occult lymph node metastasis in patients with oral cancer, malignant salivary gland tumors, and TMJ osteoarthritis. Most of these models showed high performance, and some of them even outperformed human experts. The models with performance on par with human experts have the potential to serve as clinically practicable tools to achieve the earliest possible diagnosis and treatment, leading to a more precise and personalized approach for the management of maxillofacial diseases. Challenges and issues, including the lack of the generalizability and explainability of deep learning models and the uncertainty in the reproducibility and stability of radiomic features, should be overcome to gain the trust of patients, providers, and healthcare organizers for daily clinical use of these models
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