Bibek Aryal

Dr. Bibek Aryal

Microsoft (United States), Redmond, Oregon, USA
orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 July 2016 in Obesity
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Journal Article
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TSToshiaki Shimizu
Toshiaki Shimizu
Munekazu YamakuchiMunekazu Yamakuchi
Munekazu Yamakuchi
KBKamal Krishna Biswas
Kamal Krishna Biswas
Bibek AryalBibek Aryal
Bibek Aryal
SYShingo Yamada
Shingo Yamada
IMIkuro Maruyama
Ikuro Maruyama
Objective: Obesity is a chronic inflammatory disease, and adipocytes contribute to obesity‐associated inflammation by releasing inflammatory mediators. High mobility group box 1 (HMGB1), a highly conserved DNA‐binding protein, mainly localized to cell nuclei, has been recently recognized as an innate pro‐inflammatory mediator when released extracellularly. It was hypothesized that HMGB1 is an adipocytokine that acts as an innate pro‐inflammatory mediator in white adipose tissue (WAT) of patients with obesity and is associated with insulin resistance. Additionally, it was hypothesized that HMGB1 secretion is regulated by adiponectin.Methods: 3T3‐L1 cells were differentiated into mature adipocytes. After tumor necrosis factor‐α (TNF‐α) stimulation, HMGB1 in culture media was measured. Localizations of HMGB1 in 3T3‐L1 adipocytes and human WAT were examined by immunostaining.Results: HMGB1 was secreted from TNF‐α‐induced 3T3‐L1 adipocytes through JNK signaling. HMGB1‐activated MAP kinases (ERK1/2, JNK) and suppressed insulin‐stimulated Akt phosphorylation in 3T3‐L1 adipocytes. The cytoplasm in 3T3‐L1 adipocytes and adipocytes of WAT from a patient with obesity was intensely stained with HMGB1. Adiponectin partially inhibited TNF‐α‐induced HMGB1 secretion from 3T3‐L1 adipocytes.Conclusions: These findings suggest that HMGB1 is a pro‐inflammatory adipocytokine involved in WAT inflammation and insulin resistance in patients with obesity, which may contribute to the progression of metabolic syndrome, and that adiponectin protects against HMGB1‐induced adipose tissue inflammation.

14 November 2021 in Remote Sensing
Verified
Journal Article
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Bibek AryalBibek Aryal
Bibek Aryal
SEStephen M Escarzaga
Stephen M Escarzaga
Sergio Vargas ZesatiSergio Vargas Zesati
Sergio Vargas Zesati
Miguel Velez-ReyesMiguel Velez-Reyes
Miguel Velez-Reyes
OFOlac Fuentes
Olac Fuentes
CTCraig Tweedie
Craig Tweedie
Precise coastal shoreline mapping is essential for monitoring changes in erosion rates, surface hydrology, and ecosystem structure and function. Monitoring water bodies in the Arctic National Wildlife Refuge (ANWR) is of high importance, especially considering the potential for oil and natural gas exploration in the region. In this work, we propose a modified variant of the Deep Neural Network based U-Net Architecture for the automated mapping of 4 Band Orthorectified NOAA Airborne Imagery using sparsely labeled training data and compare it to the performance of traditional Machine Learning (ML) based approaches—namely, random forest, xgboost—and spectral water indices—Normalized Difference Water Index (NDWI), and Normalized Difference Surface Water Index (NDSWI)—to support shoreline mapping of Arctic coastlines. We conclude that it is possible to modify the U-Net model to accept sparse labels as input and the results are comparable to other ML methods (an Intersection-over-Union (IoU) of 94.86% using U-Net vs. an IoU of 95.05% using the best performing method).

1 March 2016 in PLOS ONE
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Bibek AryalBibek Aryal
Bibek Aryal
TSToshiaki Shimizu
Toshiaki Shimizu
JKJun Kadono
Jun Kadono
AFAkira Furoi
Akira Furoi
TKTeruo Komokata
Teruo Komokata
YIYutaka Imoto
Yutaka Imoto
Liver regeneration (LR) involves an early inductive phase characterized by the proliferation of hepatocytes, and a delayed angiogenic phase distinguished by the expansion of non-parenchymal compartment. The interest in understanding the mechanism of LR has lately shifted from the proliferation and growth of parenchymal cells to vascular remodeling during LR. Angiogenesis accompanied by LR exerts a pivotal role to accomplish the process. Vascular endothelial growth factor (VEGF) has been elucidated as the most dynamic regulator of angiogenesis. From this perspective, platelet derived/Intra-platelet (IP) VEGF-A should be associated with LR. Thirty-seven patients diagnosed with hepatocellular carcinoma and undergoing partial hepatectomy (PH) were enrolled in the study. Serum and IP VEGF-A was monitored preoperatively and at four weeks of PH. Liver volumetry was determined on computer models derived from computed tomography (CT) scan. Serum and IP VEGF-A was significantly elevated at four weeks of PH. Preoperative IP VEGF-A was higher in patients with advanced cancer and vascular invasion. Postoperative IP VEGF-A was higher after major liver resection. There was a statistically significant correlation between postoperative IP VEGF-A and the future remnant liver volume. Moreover, the soluble vascular endothelial growth factor receptor-1 (sVEGFR1) was distinctly down-regulated suggesting a fine-tuned angiogenesis at the later phase of LR. IP VEGF-A is overexpressed during later phase of LR suggesting its implications in inducing angiogenesis during LR.

1 January 2017 in Journal of Cancer
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Journal Article
Open access
Bibek AryalBibek Aryal
Bibek Aryal
TSToshiaki Shimizu
Toshiaki Shimizu
JKJun Kadono
Jun Kadono
AFAkira Furoi
Akira Furoi
TKTeruo Komokata
Teruo Komokata
YIYutaka Imoto
Yutaka Imoto
Purpose: Serotonin (5-hydroxytryptamine, 5-HT) is well known for its growth stimulatory effect on several types of carcinoma and tumor cells. Since a large portion of 5-HT is stored and transported by platelets, the aim of this study was to assess the influence of platelet-sequestered 5-HT on post-resection hepatocellular carcinoma (HCC) recurrence.

24 November 2022 in Remote Sensing
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Journal Article
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Rocky TalchabhadelRocky Talchabhadel
Rocky Talchabhadel
SSSuraj Shah
Suraj Shah
Bibek AryalBibek Aryal
Bibek Aryal
Accurate accounting of spatiotemporal variability of precipitation is essential for understanding the changing climate. Among the available precipitation estimates, the Global Precipitation Measurement (GPM) is an international satellite network providing advanced global precipitation estimates. The integrated multi-satellite retrievals for GPM (IMERG) algorithm combines information from the GPM satellite constellation to estimate precipitation and yields a better performance in detecting precipitation events and spatial resolution. Here, we used twenty years (2001–2020) of IMERG Final data over the entire Nepal to analyze the spatial and temporal distribution of precipitation. This study evaluates the dynamic characteristics of the precipitation amounts, intensities, frequencies, and other relevant data across Nepal, using four IMERG datasets: (i) microwave only, (ii) infrared only, (iii) multi satellites gauge uncalibrated, and (iv) multi satellites gauge calibrated. A total of 28 precipitation indices was computed: threshold-based counts, consecutive days, precipitation amounts and extremes, precipitation intensity, percentile-based extremities, proportion-based indices, and additional seasonal indices. Results show that all four IMERG datasets are promising in capturing spatial details. The frequency of wet days corresponds with ground-based precipitation. Still, most indices, including consecutive wet days, annual and monsoon precipitation, and days when precipitation equaled or exceeded 20 and 50 mm, were substantially underestimated. In addition, the microwave-only dataset highly underestimated the precipitation amount. Notably, a substantial proportion of false alarms is a problem for all four IMERG datasets. Moreover, our results demonstrate that the IMERG uncalibrated dataset tends to overestimate precipitation during heavy precipitation events. These advantages and shortcomings of IMERG datasets over the rugged terrain of Nepal can provide useful feedback for sensor and algorithm developers to overcome limitations and improve retrieval algorithms. The study findings are helpful to the broader data users and practitioners for effective water decision applications.

27 June 2018 in Canadian Journal of Gastroenterology and Hepatology
Verified
Journal Article
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Bibek AryalBibek Aryal
Bibek Aryal
Munekazu YamakuchiMunekazu Yamakuchi
Munekazu Yamakuchi
TSToshiaki Shimizu
Toshiaki Shimizu
JKJun Kadono
Jun Kadono
AFAkira Furoi
Akira Furoi
YIYutaka Imoto
Yutaka Imoto
Liver pathophysiology can, directly and indirectly, impose morphological or biochemical abnormalities of the platelets. Conversely, platelets are also able to regulate the promitogenic and profibrotic signals on liver pathobiology. Platelet contribution to the liver pathophysiology is typically facilitated by the platelet-derived growth factors that are sequestered in different subsets of alpha and dense granules, and the release of these growth factors is synchronized according to the stage and type of liver disease or injury. Thus, platelets harbor clinically relevant information with potential diagnostic and prognostic implications in liver diseases. Hepatocellular carcinoma (HCC) largely influences the platelet kinetics, and a growing body of evidence has recognized its association with HCC occurrence or prognosis. This narrative review summarizes the progress made on implicating platelet as a diagnostic and prognostic tool for HCC; the review also dissects the contradictory results from earlier studies and reflects how combining platelet-based information may enable more reliable test for diagnostic and prognostic evaluation of HCC.