ARTICLE | doi:10.20944/preprints202307.1650.v2
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: metric learning; kernel methods; weighted geometric mean
Online: 1 August 2023 (11:46:59 CEST)
This paper propose a kernel geometric mean metric learning (KGMML) algorithm. The basic idea is to obtain the closed-form solution of the geometric mean metric learning (GMML) algorithm in the high-dimensional feature space determined by the kernel function. Then, the solution is generalized as a form of kernel matrix by using the integral representation of the weighted geometric mean and the Woodbury matrix in this new feature space. Experimental results on 15 datasets show that the proposed algorithm can effectively improve the accuracy of the GMML algorithm and other metric algorithms.
ARTICLE | doi:10.20944/preprints202312.0419.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: silicon nanobelt; NBFET; nanobelt biosensor; degradation; ions penetration; surface functionalization
Online: 7 December 2023 (03:09:25 CET)
Field-effect transistor (FET)-based biosensors stand as powerful analytical tools for detecting trace-specific biomolecules in diverse sample matrices, especially in the realms of pandemics and infectious diseases. The primary concern in applying these biosensors is their stability, a factor directly impacting the accuracy and reliability of sensing over extended durations. The risk of biosensor degradation is substantial, potentially jeopardizing sensitivity and selectivity and leading to inaccurate readings, including the possibility of false positives or negatives. This paper delves into the documented degradation of silicon nanobelt FET (NBFET) biosensors induced by buffer solutions. The results highlight a positive correlation between immersion time and the threshold voltage of NBFET devices. Secondary ion mass spectrometry analysis demonstrates a gradual increase in sodium and potassium ion concentrations within the silicon as immersion days progress. This outcome is ascribed to the nanobelt's exposure to the buffer solution during the biosensing period, enabling ion penetration from the buffer into the silicon. The study emphasizes the critical need to address buffer solution-induced degradation to ensure the long-term stability and performance of FET-based biosensors in practical applications.
ARTICLE | doi:10.20944/preprints202309.0703.v1
Subject: Public Health And Healthcare, Physical Therapy, Sports Therapy And Rehabilitation Keywords: ankle pump movement; ankle joint flexion and extension movement monitoring; pressure sensor; STM32
Online: 12 September 2023 (04:46:28 CEST)
Ankle joint flexion and extension exercises play an important role in the rehabilitation training of patients who have been injured or bedridden for a long time before and after surgery. Accurately guiding patients to perform ankle flexion and extension exercises can significantly reduce deep vein thromboembolism. Currently, most ankle rehabilitation devices focus on assisting patients with ankle flexion and extension movements, and there is a lack of devices for effectively monitoring these movements. In this study, we designed an ankle joint flexion and extension movement monitoring device based on a pressure sensor. It is composed of an STM32 microcontroller, a pressure sensor, an HX711A/D conversion chip, and an ESP8266 WiFi communication module. The value of force and effective number of ankle joint flexion and extension movements were obtained. An experimental device was designed to verify the accuracy of the system. The results showed that the device can effectively monitor and control ankle flexion and extension movements remotely, ultimately ensuring that the patient can effectively monitor and grasp the active ankle pump movement.
ARTICLE | doi:10.20944/preprints201810.0034.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: T-2 toxin, toxicity, autophagy, apoptosis
Online: 2 October 2018 (16:51:09 CEST)
T-2 toxin produced by fungi of Fusarium genus is highly toxic to human and animals and has been shown to induce apoptosis in various organs/tissues. Apoptosis and autophagy are interconnected processes and these interactions are important for cellular homeostasis as well as pathogenesis. In this study, we report for the first time that T-2 toxin induced autophagy in human liver cells (L02). We showed that T-2 toxin induced the formation of acidic vesicular organelles, concordant with the time and dose-dependent alterations in LC3-phosphatidylethanolamine conjugate (LC3-II) LC3-I/II and p62/SQSTM1 suggesting an enhanced autophagic flux. The T-2 toxin-induced formation of autophagosome and lysosomal fusion was observed by expressing mRFP-GFP-LC3 in L02 cells by lentiviral transduction, and autophagosome was observed by transmission electron microcopy. We found that while T-2 toxin activated both apoptosis and autophagy, activation of autophagy appears to be a leading event reflecting the protective mechanism of cells against the insults by T-2 toxin. Activating autophagy by rapamycin (RAPA) inhibited the apoptosis while suppressing autophagy by chloroquine greatly enhanced the T-2 toxin-induced apoptosis suggesting the crosstalk of autophagy and apoptosis. In summary, our study showed that activation of autophagy protects liver cells from T-2 toxin-induced apoptosis suggesting autophagy may be targeted for prevention of the T-2 toxin-induced toxicity in human and animals.
ARTICLE | doi:10.20944/preprints201709.0143.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: fibrinolytic acticity; FGFC1; plasminogen activator; plasminogen; enzymatic kinetic
Online: 28 September 2017 (09:17:34 CEST)
A marine fibrinolytic compound FGFC1 enhancing fibrinolysis was obtained involving in enzymatic kinetic parameters of reciprocal activation system with single chain urokinase type plasminogen activator and plasminogen. FGFC1, a kind of bisindole alkaloid from a metabolite of rare marine fungi Starchbotrys longispora FG216, modulated enzymatic kinetic parameters including fibrinolytic reaction rate and fibrin degradation characteristics. The enzymatic kinetics of fibrinolysis was described based on enzymatic reaction of chromogenic-substrate associated with p-nitroaniline (p-NA). While single chain urokinase-type plasminogen activator (pro-uPA) actived plasminogen, Kcat and kcat/km increased significantly with increase of FGFC1 concentration. Moreover, Kcat and kcat/km exhibited 26.5-fold and 22.8-fold enhanced activity at the concentration of 40 μg•mL−1 of FGFC1, respectively. The results suggested that FGFC1 improved significantly the maximum catalytic efficiency and the total catalytic activity of fibrinolysis base on the reciprocal activation of pro-uPA and plasminogen. Km increased with increasing FGFC1 concentration, which indicated that FGFC1 decreased slightly the affinity activity of pro-uPA and plasminogen versus enzyme substrate. The marine bisindole alkaloid FGFC1 enhanced fibrinolysis which was taken on enzymatic kinetic characteristics.
ARTICLE | doi:10.20944/preprints201801.0271.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: breast cancer; ginkgolic acid C13:0; mechanism; CYP1B1
Online: 29 January 2018 (09:57:10 CET)
Ginkgolic acids (GA) have been reported to exhibit anticancer properties, however, the mechanisms remain unclear. This study aims to investigate the mechanisms of GA C13:0 that was isolated from Ginkgo biloba exocarp (GBE) for anti-proliferation, pro-apoptosis and anti-migration effects in human MCF-7 and mouse 4T-1 breast cancer cells. The cytotoxic effect, apoptosis induction and migration inhibition were measured using MTT, TUNEL and Wound healing assays. The expression of mRNA and protein were determined using qPCR and Western blot. Our results showed that no cytotoxicity was found at concentrations of C13:0 below 100µM. The effects of GA C13:0 was further demonstrated by up-regulation of the Bax/Bcl-2 apoptosis pathway and the expression of Apaf-1 protein in the mitochondria. In addition, GA C13:0 also suppressed cell migration and epithelial to mesenchymal transition (EMT) with the increase of E-cadherin expression accompanied by the decrease of Snail, MMP-2, MMP-9 and Vimentin expression. Moreover, GA C13:0 induced cytochrome P450 (CYP) 1B1 expression in aryl hydrocarbon receptor (AhR) pathway. Notably, the up-regulation of CYP1B1 also might play a pivotal regulatory role in mitochondrial and EMT pathways in MCF-7 and 4T-1 cells. Our results may have implications for the development of anticancer agents containing GA as functional additives.