The Advanced Applications For Optical Coherence Tomography In Skin Imaging

Optical coherence tomography (OCT), based on the principle of interferometry, is a fast and non-invasive imaging modality, which has been approved by FDA for dermatologic applications. OCT has high spatial resolution up to micrometer scale compared to traditional ultrasound imaging. In addition, OCT can provide real-time cross-sectional images with 1 to 2 mm penetration depth, which makes it an ideal imaging technique to assess the skin micro-morphology and pathology without any tissue removal. Many studies have investigated the possibilities of using OCT to evaluate dermatologic conditions, such as skin cancer, dermatitis, psoriasis, and skin damages. Hence, OCT has tremendous potential to provide skin histological and pathological information and assist differential diagnosis of various skin diseases. In this study, we used a swept-source OCT with 1305 nm central wavelength to explore its advanced applications in dermatology. This dissertation consists of four major research projects. First, we explored the feasibility of OCT imaging for assisting real-time visualization in skin biopsy. We showed that OCT could be used to guide and track a needle insertion in mouse skin in real-time. The structure of skin and the movement of needle can be clearly seen on the OCT images without any time delay during the procedures. Next, we tested the concept of performing the punch biopsy using OCT hand-held probe attached to a piercing tip in a phantom. We proved that using the OCT is a reliable technique to delineate the margin of lesion in phantom. And it is possible to perform the punch biopsy with the OCT probe. Second, we tested the performance of contrast-enhanced OCT in melanoma detection in an in vitro study. Melanoma is the most lethal type of skin cancer. Early detection could significantly improve the long-term survival rate of patients. In this initial study, a contrast agent (Gal3-USGNPs) is developed by conjugating melanoma biomarker (Gal3) to ultra-small gold nanoparticles (USGNPs). We showed that the contrast agent can differentiate B16 melanoma cells from normal skin keratinocytes in vitro. To avoid systemic administration of USGNPs, the third project continues to explore the enhanced topical delivery of USGNPs. In this study, we used OCT to monitor the topical delivery of nanoparticles on pig skin over time. And the diffusion and penetration of USGNPs in skin can be improved by applying chemical and physical enhancers such as DMSO and sonophoresis. Finally, in addition to image the cross-sectional structure of skin, we also aim to extract quantitative information from OCT images. The skin optical properties such as attenuation coefficient can be measured from OCT images. We measured and compared the skin attenuation coefficient in the skin of forehead and lateral hip, the skin of three different age groups, and the skin of three different Fitzpatrick types. The statistical analysis showed that epidermis has much higher attenuation coefficient than dermis. And the skin type V & VI have a relatively lower attenuation coefficient than the other skin types. These studies could aid the detection of skin cancer using imaging techniques and provide some new insights into the future applications of OCT in dermatology

Transfer Learning for Context-Aware Spoken Language Understanding

Spoken language understanding (SLU) is a key component of task-oriented dialogue systems. SLU parses natural language user utterances into semantic frames. Previous work has shown that incorporating context information significantly improves SLU performance for multi-turn dialogues. However, collecting a large-scale human-labeled multi-turn dialogue corpus for the target domains is complex and costly. To reduce dependency on the collection and annotation effort, we propose a Context Encoding Language Transformer (CELT) model facilitating exploiting various context information for SLU. We explore different transfer learning approaches to reduce dependency on data collection and annotation. In addition to unsupervised pre-training using large-scale general purpose unlabeled corpora, such as Wikipedia, we explore unsupervised and supervised adaptive training approaches for transfer learning to benefit from other in-domain and out-of-domain dialogue corpora. Experimental results demonstrate that the proposed model with the proposed transfer learning approaches achieves significant improvement on the SLU performance over state-of-the-art models on two large-scale single-turn dialogue benchmarks and one large-scale multi-turn dialogue benchmark.Comment: 6 pages, 3 figures, ASRU201

Are you a spontaneous traveler? Effect of sensation seeking on tourist planfulness in the mobile era

Drawn upon optimum stimulation level theory, and in view of the impact of mobile terminal usage on tourist decision-making, the present study aims to investigate how personality (i.e., sensation seeking) influences tourist trip planning behavior (i.e., tourist planfulness) in the mobile era. A sample of 344 respondents in China completed measures of sensation seeking, travel risk perception, smartphone usage, as well as tourist planfulness. Results indicated that sensation seeking was negatively associated with tourist planfulness and travel risk perception partially mediated this association. Besides, both the direct effect of sensation seeking on tourist planfulness and the indirect effect of travel risk perception were moderated by smartphone usage, in that these effects were stronger for tourists with a high-level of smartphone usage than those with low-level smartphone usage. This study can significantly advance existing research on tourist behavior from the perspective of personality and reconfiguring our traditional understanding on tourist decision-making in the mobile era. Our study may also provide indicative support for theoretical perspective that information technology is changing customer behavior

Is photoacoustic imaging clinically safe: evaluation of possible thermal damage due to laser-tissue interaction

Photoacoustic imaging is a breakthrough imaging modality that combines the spatial resolution of ultrasound imaging with the contrast of optical imaging. This imaging technique is being pushed towards clinical acceptance for many applications, such as noninvasive diagnosis and management of a multitude of neoplastic lesions. However, a rigorous evaluation of the tissue thermal response to the laser illumination is required prior to the clinical translation. In this study, we assessed the temperature rise profile and microstructural damage of the skin due to the laser-tissue interaction using in-vivo mouse models. We compared the effect of two different laser frequencies (10 Hz and 30 Hz) on the skin and studied if the use of a cooling method could be clinically useful in preventing tissue necrosis. Two biopsies were taken from each mouse 48 hours after laser exposure; one from the skin directly exposed to the laser and one from neighboring healthy tissue. When the lower frequency laser was used, no necrosis was found on histologic analysis. However, when the higher frequency laser was used, necrosis was noted in the epidermis, dermal collagen, and hair follicles at the site of laser exposure. Use of the cooling method with the higher frequency laser led to no tissue necrosis. Overall, it appears that photoacoustic imaging is likely safe when lower frequency lasers are used, and the implementation of the cooling method seems to mitigate necrosis when the use of a higher frequency laser is warranted. This opens up exciting new possibilities for a noninvasive way of diagnosing and evaluating a variety of lesions, including malignant tumors. However, some further studies are needed before photoacoustic imaging can be clinically used in human subjects

The mechanism of traditional medicine in alleviating ulcerative colitis: regulating intestinal barrier function

Ulcerative colitis (UC) is an idiopathic inflammatory disease mainly affects the large bowel and the rectum. The pathogenesis of this disease has not been fully elucidated, while the disruption of the intestinal barrier function triggered by various stimulating factors related to the host genetics, immunity, gut microbiota, and environment has been considered to be major mechanisms that affect the development of UC. Given the limited effective therapies, the treatment of this disease is not ideal and its incidence and prevalence are increasing. Therefore, developing new therapies with high efficiency and efficacy is important for treating UC. Many recent studies disclosed that numerous herbal decoctions and natural compounds derived from traditional herbal medicine showed promising therapeutic activities in animal models of colitis and have gained increasing attention from scientists in the study of UC. Some of these decoctions and compounds can effectively alleviate colonic inflammation and relieve clinical symptoms in animal models of colitis via regulating intestinal barrier function. While no study is available to review the underlying mechanisms of these potential therapies in regulating the integrity and function of the intestinal barrier. This review aims to summarize the effects of various herbal decoctions or bioactive compounds on the severity of colonic inflammation via various mechanisms, mainly including regulating the production of tight junction proteins, mucins, the composition of gut microbiota and microbial-associated metabolites, the infiltration of inflammatory cells and mediators, and the oxidative stress in the gut. On this basis, we discussed the related regulators and the affected signaling pathways of the mentioned traditional medicine in modulating the disruption or restoration of the intestinal barrier, such as NF-κB/MAPK, PI3K, and HIF-1α signaling pathways. In addition, the possible limitations of current studies and a prospect for future investigation and development of new UC therapies are provided based on our knowledge and current understanding. This review may improve our understanding of the current progression in studies of traditional medicine-derived therapies in protecting the intestinal barrier function and their roles in alleviating animal models of UC. It may be beneficial to the work of researchers in both basic and translational studies of UC

Push–pull type manganese (III) corroles

The synthesis of three low symmetry A2B type Mn(III)triarylcorroles with meso-aryl substituents that provide push–pull electron-donating and -withdrawing properties is reported. An analysis of the structure-property relationships for the optical and redox properties has been carried out through a comparison with the results of theoretical calculations. The results demonstrate that A2B type Mn(III)triarylcorroles interact strongly with cell-free circulating tumor deoxyribonucleic acid (ctDNA) in solution, and that the interaction constants are enhanced when a stronger electron-donating substituent is introduced at the 10-position of the meso-triarylcorrole ligand

Insights into lignocellulose degradation: comparative genomics of anaerobic and cellulolytic Ruminiclostridium-type species

Mesophilic, anaerobic, and cellulolytic Ruminiclostridium-type bacterial species can secrete an extracellular, multi-enzyme machinery cellulosome, which efficiently degrades cellulose. In this study, we first reported the complete genome of Ruminiclostridium papyrosolvens DSM2782, a single circular 5,027,861-bp chromosome with 37.1% G + C content, and compared it with other Ruminiclostridium-type species. Pan-genome analysis showed that Ruminiclostridium-type species share a large number of core genes to conserve basic functions, although they have a high level of intraspecific genetic diversity. Especially, KEGG mapping revealed that Ruminiclostridium-type species mainly use ABC transporters regulated by two-component systems (TCSs) to absorb extracellular sugars but not phosphotransferase systems (PTSs) that are employed by solventogenic clostridia, such as Clostridium acetobutylicum. Furthermore, we performed comparative analyses of the species-specific repertoire of CAZymes for each of the Ruminiclostridium-type species. The high similarity of their cohesins suggests a common ancestor and potential cross-species recognition. Additionally, both differences between the C-terminal cohesins and other cohesins of scaffoldins and between the dockerins linking with cellulases and other catalytic domains indicate a preference for the location of cellulosomal catalytic subunits at scaffoldins. The information gained in this study may be utilized directly or developed further by genetic engineering and optimizing enzyme systems or cell factories for enhanced biotechnological biomass deconstruction and biofuel production

Automatic Recognition of Laryngoscopic Images Using a Deep-Learning Technique

Objectives/Hypothesis: To develop a deep-learning–based computer-aided diagnosis system for distinguishing laryngeal neoplasms (benign, precancerous lesions, and cancer) and improve the clinician-based accuracy of diagnostic assessments of laryngoscopy findings. Study Design: Retrospective study. Methods: A total of 24,667 laryngoscopy images (normal, vocal nodule, polyps, leukoplakia and malignancy) were collected to develop and test a convolutional neural network (CNN)-based classifier. A comparison between the proposed CNN-based classifier and the clinical visual assessments (CVAs) by 12 otolaryngologists was conducted. Results: In the independent testing dataset, an overall accuracy of 96.24% was achieved; for leukoplakia, benign, malignancy, normal, and vocal nodule, the sensitivity and specificity were 92.8% vs. 98.9%, 97% vs. 99.7%, 89% vs. 99.3%, 99.0% vs. 99.4%, and 97.2% vs. 99.1%, respectively. Furthermore, when compared with CVAs on the randomly selected test dataset, the CNN-based classifier outperformed physicians for most laryngeal conditions, with striking improvements in the ability to distinguish nodules (98% vs. 45%, P <.001), polyps (91% vs. 86%, P <.001), leukoplakia (91% vs. 65%, P <.001), and malignancy (90% vs. 54%, P <.001). Conclusions: The CNN-based classifier can provide a valuable reference for the diagnosis of laryngeal neoplasms during laryngoscopy, especially for distinguishing benign, precancerous, and cancer lesions. Level of Evidence: NA Laryngoscope, 130:E686–E693, 2020

Structure-Function Analysis of Barley NLR Immune Receptor MLA10 Reveals Its Cell Compartment Specific Activity in Cell Death and Disease Resistance

Plant intracellular immune receptors comprise a large number of multi-domain proteins resembling animal NOD-like receptors (NLRs). Plant NLRs typically recognize isolate-specific pathogen-derived effectors, encoded by avirulence (AVR) genes, and trigger defense responses often associated with localized host cell death. The barley MLA gene is polymorphic in nature and encodes NLRs of the coiled-coil (CC)-NB-LRR type that each detects a cognate isolate-specific effector of the barley powdery mildew fungus. We report the systematic analyses of MLA10 activity in disease resistance and cell death signaling in barley and Nicotiana benthamiana. MLA10 CC domain-triggered cell death is regulated by highly conserved motifs in the CC and the NB-ARC domains and by the C-terminal LRR of the receptor. Enforced MLA10 subcellular localization, by tagging with a nuclear localization sequence (NLS) or a nuclear export sequence (NES), shows that MLA10 activity in cell death signaling is suppressed in the nucleus but enhanced in the cytoplasm. By contrast, nuclear localized MLA10 is sufficient to mediate disease resistance against powdery mildew fungus. MLA10 retention in the cytoplasm was achieved through attachment of a glucocorticoid receptor hormone-binding domain (GR), by which we reinforced the role of cytoplasmic MLA10 in cell death signaling. Together with our data showing an essential and sufficient nuclear MLA10 activity in disease resistance, this suggests a bifurcation of MLA10-triggered cell death and disease resistance signaling in a compartment-dependent manner