Development of Channeled Nanofibrous Scaffolds for Oriented Tissue Engineering

A tissue‐engineering scaffold resembling the structure of the natural extracellular matrix can often facilitate tissue regeneration. Nerve and tendon are oriented micro‐scale tissue bundles. In this study, a method combining injection molding and thermally induced phase separation techniques is developed to create single‐ and multiple‐channeled nanofibrous poly( L ‐lactic acid) scaffolds. The overall shape, the number and spatial arrangement of channels, the channel wall matrix architecture, the porosity and mechanical properties of the scaffolds are all tunable. The porous NF channel wall matrix provides an excellent microenvironment for protein adsorption and the attachment of PC12 neuronal cells and tendon fibroblast cells, showing potential for neural and tendon tissue regeneration. A method combining injection molding and thermally induced phase separation is developed to create single‐ and multiple‐channeled nanofibrous polymer scaffolds. The porous nanofibrous channel wall provides an excellent microenvironment for protein adsorption and cell attachment, showing potential for nerve and tendon regeneration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92054/1/761_ftp.pd

Enhancing Semantics in Multimodal Chain of Thought via Soft Negative Sampling

Chain of thought (CoT) has proven useful for problems requiring complex reasoning. Many of these problems are both textual and multimodal. Given the inputs in different modalities, a model generates a rationale and then uses it to answer a question. Because of the hallucination issue, the generated soft negative rationales with high textual quality but illogical semantics do not always help improve answer accuracy. This study proposes a rationale generation method using soft negative sampling (SNSE-CoT) to mitigate hallucinations in multimodal CoT. Five methods were applied to generate soft negative samples that shared highly similar text but had different semantics from the original. Bidirectional margin loss (BML) was applied to introduce them into the traditional contrastive learning framework that involves only positive and negative samples. Extensive experiments on the ScienceQA dataset demonstrated the effectiveness of the proposed method. Code and data are released at https://github.com/zgMin/SNSE-CoT.Comment: Accepted by LREC-COLING 202

Solid Pseudopapillary Tumor of Pancreas in a 15-year-old Female: A Case Report

Solid pseudopapillary tumor (SPT) is a very rare tumor accounting for only 1% of all pancreatic exocrine tumors. In this case, patient is a 15-year-old female with history of obesity and oligomenorrhea. She was admitted with a six-day history of severe upper abdominal pain, non-bloody vomiting and occasional diarrhea with no history of fever or sick contact. MRI abdominal examination with contrast showed a cystic 3.4 x 2.2 x 2.0 cm mass in the tail of the pancreas. Patient then underwent the distal pancreatectomy and splenectomy. Grossly, the tumor mass is well-circumscribed and has a tan/yellow cystic cut surface. Microscopically, most of the tumor tissue is necrotic.  Sheets of cells demonstrate pseudopapillary arrangement in the preserved area.  The nuclei are uniform without apparent mitotic figures and cytoplasm is moderate and eosinophilic. Immunohistochemistry study revealed that tumor cells are positive for CD10, progesterone receptor, synaptophysin and nuclear beta-catenin staining. Diagnosis of this case is challenging because extensive necrosis of the tumor tissue, however, the small areas of residual tumor still retain the pseudopapillary architecture and nested pattern. Individual tumor cells have monotonous low grade character. Immunoprofile also supports the diagnosis of solid pseudopapillary tumor. [N A J Med Sci. 2019;12(1):021-023.   DOI:  10.7156/najms.2019.1201021

SwinFIR: Revisiting the SwinIR with Fast Fourier Convolution and Improved Training for Image Super-Resolution

Transformer-based methods have achieved impressive image restoration performance due to their capacities to model long-range dependency compared to CNN-based methods. However, advances like SwinIR adopts the window-based and local attention strategy to balance the performance and computational overhead, which restricts employing large receptive fields to capture global information and establish long dependencies in the early layers. To further improve the efficiency of capturing global information, in this work, we propose SwinFIR to extend SwinIR by replacing Fast Fourier Convolution (FFC) components, which have the image-wide receptive field. We also revisit other advanced techniques, i.e, data augmentation, pre-training, and feature ensemble to improve the effect of image reconstruction. And our feature ensemble method enables the performance of the model to be considerably enhanced without increasing the training and testing time. We applied our algorithm on multiple popular large-scale benchmarks and achieved state-of-the-art performance comparing to the existing methods. For example, our SwinFIR achieves the PSNR of 32.83 dB on Manga109 dataset, which is 0.8 dB higher than the state-of-the-art SwinIR method

A Rare Case Report of Primary Leiomyosarcoma of Distal Femur Bone in a Patient with Multiple Myeloma and Review of Literature

Primary leiomyosarcoma of bone is rare, with < 0.7% incidence of all primary malignant bone tumors. Here we report a primary leiomyosarcoma of bone arising in a patient with multiple myeloma. The patient is a 72-year-old male who was initially diagnosed with multiple myeloma (IgG Kappa) in 2007 which presented as a large plasmacytoma involving his thoracic vertebrae. He was treated with chemotherapy and eventually had a stem cell transplant in 2015. In 2017, a routine skeletal survey demonstrated a solitary lytic lesion in the right distal femur. The lesion grew fast and doubled in size to 7.9 cm within one year. The lesion was biopsied and proven to be a leiomyosarcoma. A total body PET/CT scan showed no evidence of other primary tumors or metastatic disease. The patient then underwent a distal femur resection. Grossly, majority of the tumor involved distal femur cortical bone and medullary cavity with focal extension into the surrounding soft tissue. Microscopically, the tumor consisted of fascicles of spindle cells with a focal storiform growth pattern. The tumor cells had eosinophilic cytoplasm and focally pleomorphic nuclei.  The tumor cells were positive for SMA and Calponin and negative for Desmin, Myo-D1, Myogenin and S-100 immunohistochemical stains. The morphology and immunoprofile favored a diagnosis of pleomorphic leiomyosarcoma. Primary leiomyosarcoma of bone is a rare tumor and this patient’s history of multiple myeloma made it even more challenging to make an early clinical diagnosis.[N A J Med Sci. 2020;1(1):024-027.   DOI:  10.7156/najms.2020.1301024]  Key Words: primary leiomyosarcoma, femur, multiple myelom

Nanofibrous Spongy Microspheres for the Delivery of Hypoxia-primed Human Dental Pulp Stem Cells to Regenerate Vascularized Dental Pulp

Dental pulp infection and necrosis are widespread diseases. Conventional endodontic treatments result in a devitalized and weakened tooth. In this work, we synthesized novel star-shaped polymer to self-assemble into unique nanofibrous spongy microspheres (NF-SMS), which were used to carry human dental pulp stem cells (hDPSCs) into the pulp cavity to regenerate living dental pulp tissues. It was found that NF-SMS significantly enhanced hDPSCs attachment, proliferation, odontogenic differentiation and angiogenesis, as compared to control cell carriers. Additionally, NF-SMS promoted vascular endothelial growth factor (VEGF) expression of hDPSCs in a 3D hypoxic culture. Hypoxia-primed hDPSCs/NF-SMS complexes were injected into the cleaned pulp cavities of rabbit molars for subcutaneous implantation in mice. After 4 weeks, the hypoxia group significantly enhanced angiogenesis inside the pulp chamber and promoted the formation of ondontoblast-like cells lining along the dentin-pulp interface, as compared to the control groups (hDPSCs alone group, NF-SMS alone group, and hDPSCs/NF-SMS group pre-cultured under normoxic conditions). Furthermore, in an in situ dental pulp repair model in rats, hypoxia-primed hDPSCs/NF-SMS were injected to fully fill the pulp cavity and regenerate pulp-like tissues with a rich vasculature and a histological structure similar to the native pulp

The use of comparative genomic hybridization to characterize genome dynamics and diversity among the serotypes of Shigella

<p>Abstract</p> <p>Background</p> <p>Compelling evidence indicates that <it>Shigella </it>species, the etiologic agents of bacillary dysentery, as well as <it>enteroinvasive Escherichia coli</it>, are derived from multiple origins of <it>Escherichia coli </it>and form a single pathovar. To further understand the genome diversity and virulence evolution of <it>Shigella</it>, comparative genomic hybridization microarray analysis was employed to compare the gene content of <it>E. coli </it>K-12 with those of 43 <it>Shigella </it>strains from all lineages.</p> <p>Results</p> <p>For the 43 strains subjected to CGH microarray analyses, the common backbone of the <it>Shigella </it>genome was estimated to contain more than 1,900 open reading frames (ORFs), with a mean number of 726 undetectable ORFs. The mosaic distribution of absent regions indicated that insertions and/or deletions have led to the highly diversified genomes of pathogenic strains.</p> <p>Conclusion</p> <p>These results support the hypothesis that by gain and loss of functions, <it>Shigella </it>species became successful human pathogens through convergent evolution from diverse genomic backgrounds. Moreover, we also found many specific differences between different lineages, providing a window into understanding bacterial speciation and taxonomic relationships.</p