ARTICLE | doi:10.20944/preprints201808.0385.v1
Subject: Engineering, Mechanical Engineering Keywords: sparse reconstruction, extreme learning machines, sensors, SVD, POD, compressive sensing
Online: 21 August 2018 (16:18:06 CEST)
Reconstruction of fine-scale information from sparse data is often needed in practical fluid dynamics where the sensors are typically sparse and yet, one may need to learn the underlying flow structures or inform predictions through assimilation into data-driven models. Given that sparse reconstruction is inherently an ill-posed problem, the most successful approaches encode the physics into an underlying sparse basis space that spans the manifold to generate well-posedness. To achieve this, one commonly uses generic orthogonal Fourier basis or data specific proper orthogonal decomposition (POD) basis to reconstruct from sparse sensor information at chosen locations. Such a reconstruction problem is well-posed as long as the sensor locations are incoherent and can sample the key physical mechanisms. The resulting inverse problem is easily solved using $l_2$ minimization or if necessary, sparsity promoting $l_1$ minimization. Given the proliferation of machine learning and the need for robust reconstruction frameworks in the face of dynamically evolving flows, we explore in this study the suitability of non-orthogonal basis obtained from Extreme Learning Machine (ELM) auto-encoders for sparse reconstruction. In particular, we assess the interplay between sensor quantity and sensor placement for a given system dimension for accurate reconstruction of canonical fluid flows in comparison to POD-based reconstruction.
ARTICLE | doi:10.20944/preprints201902.0196.v1
Subject: Engineering, Mechanical Engineering Keywords: sparse reconstruction, sensor placement, SVD, POD, compressive sensing, machine learning
Online: 21 February 2019 (05:31:45 CET)
Sparse recovery of fluid flows using data-driven proper orthogonal decomposition (POD) basis is systematically explored in this work. Fluid flows are manifestations of nonlinear multiscale PDE dynamical systems with inherent scale separation that impact the system dimensionality. Given that sparse reconstruction is inherently an ill-posed problem, the most successful approaches require the knowledge of the underlying basis space spanning the manifold in which the system resides. In this study, we employ an approach that learns basis from singular value decomposition (SVD) of training data to reconstruct sparsely sensed information. This results in a set of four control parameters for sparse recovery, namely, the choice of basis, system dimension required for sufficiently accurate reconstruction, sensor budget and their placement. The choice of control parameters implicitly determines the choice of algorithm as either $l_2$ minimization reconstruction or sparsity promoting $l_1$ norm minimization reconstruction. In this work, we systematically explore the implications of these control parameters on reconstruction accuracy so that practical recommendations can be identified. We observe that greedy-smart sensor placement provides the best balance of computational complexity and robust reconstruction for marginally oversampled cases which happens to be the most challenging regime in the explored parameter design space.
ARTICLE | doi:10.20944/preprints202308.0009.v1
Subject: Engineering, Marine Engineering Keywords: Sea of Oman; Wave measurements; Coastal currents; ADCP; Tidal elevations
Online: 1 August 2023 (05:22:43 CEST)
The coast of Oman is observing huge coastal developments to materialize Oman Vision 2040 covering all the strategic sectors. Historical data of coastal hydrodynamic parameters is scarce, even though its importance for a proper design of coastal structures is recognized. Acoustic Doppler Current Profilers were deployed at eleven locations along the coast of Oman. These locations were selected based on their strategic importance for the country. The duration of deployment was from 60 to 265 days. The measured data of waves and current were collected and analyzed using the equipment-specific software and Excel. The significant wave heights can reach 2m along the whole coast of Oman. The southern coast is dominated by the swells. The maximum to significant wave height ratio is approximately 1.5 which is less than a value of 2 obtained using Rayleigh distribution. The coastal currents are stronger along the southern coast than those along the northern coast. The range of current magnitude is from 0.02 m/s to 0.8 m/s. This baseline study will help the public authorities in establishing permanent hydrodynamic measurement stations along the coast of Oman. Moreover, these measurements will serve the practicing engineers in designing coastal structures along the coast of Oman.
ARTICLE | doi:10.20944/preprints202007.0502.v1
Subject: Computer Science And Mathematics, Information Systems Keywords: COVID-19; contact tracing; privacy concern; secure communication; healthcare data; blockchain
Online: 22 July 2020 (06:19:47 CEST)
Contact tracing has become an indispensable tool of various extensive measures to control the spread of COVID-19 pandemic due to novel coronavirus. This essential tool helps to identify, isolate and quarantine the contacted persons of a COVID-19 patient. However, the existing contact tracing applications developed by various countries, health organizations to trace down the contacts after identifying a COVID-19 patient suffers from several security and privacy concerns. In this work, we have identified those security and privacy issues of several leading contact tracing applications and proposed a blockchain-based framework to overcome the major security and privacy challenges imposed by the applications. We have discussed the security and privacy measures that are achieved by the proposed framework to show the effectiveness against the security and privacy issues raised by the existing mobile contact tracing applications.
REVIEW | doi:10.20944/preprints202306.0036.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Bleeding Classification; Bleeding Detection; Bleeding Recognition; Bleeding Segmentation; Capsule Endoscopy; Wireless Capsule Endoscopy
Online: 1 June 2023 (05:21:04 CEST)
Capsule endoscopy (CE) has been a widely used medical imaging tool for the diagnosis of gastrointestinal tract abnormalities like bleeding. But the CE captures a huge number of image frames that are time-consuming and tedious tasks for medical experts to diagnose manually. To address this issue, researchers focused on the computer-aided bleeding detection system to identify bleeding automatically in real-time. This paper presents a systematic review of the available state-of-the-art computer-aided bleeding detection algorithms for capsule endoscopy. The review was carried out by searching five different repositories: Scopus, PubMed, IEEE Xplore, ACM Digital Library, and ScienceDirect for all original publications on computer-aided bleeding detection published between 2001 and 2021. The PRISMA methodology was used to perform the review, and 112 full-texts of scientific papers were reviewed. The contributions of this paper are I) a taxonomy for computer-aided bleeding detection algorithms for capsule endoscopy is identified, II) the available state-of-the-art computer-aided bleeding detection algorithms including various color spaces (RGB, HSV, etc.), feature extraction techniques, and classifiers are discussed, and III) identify the most effective algorithm for practical use cases. Finally, the paper is concluded by providing future direction for computer-aided bleeding detection research.
ARTICLE | doi:10.20944/preprints202001.0109.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Alzheimer’s disease; curcumin; network pharmacology; molecular simulation; neurodegeneration; TrkB/PI3K signaling; autophagy
Online: 11 January 2020 (13:53:12 CET)
Curcumin is one of the bioactive metabolites of turmeric (Curcuma longa), known for its pleiotropic pharmacological actions, including antioxidant and anti-inflammation, anticholinesterase, immunomodulation, and neuroprotection. Substantial evidence suggests the therapeutic benefits of curcumin against neurodegenerative disorders, including Alzheimer’s disease (AD), acting on a diverse array of brain targets that make the molecular mechanisms complicated. System biology level-investigation could potentially present a comprehensive molecular mechanism to delineate the neuropharmacological action of curcumin. In this study, we used integrated system pharmacology and molecular simulation analysis to gain insights into the underlying mechanism of curcumin action against AD. Network pharmacology study identified curcumin-targeted potential cellular pathways such as phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling, neurotrophin signaling, toll-like receptor (TLR) signaling, and autophagy, and proteins such as tropomyosin receptor kinase B (TrkB), liver X-receptor-beta (LXR-β), estrogen receptor-β (ER-β), mammalian target of rapamycin (mTOR), TLR-2, N-methyl-D-acetate receptor subunit 2B (GluN2B), β-secretase and glycogen synthase kinase-3β (GSK-3β), which are intimately associated with neuronal growth and survival, immune response, and inflammation. Moreover, the molecular modeling further verified that curcumin showed a significant binding affinity to mTOR, TrkB, LXR-β, TLR-2, ER-β, GluN2B, β-secretase, and GSK-3β, which are the crucial regulators of molecular and cellular processes associated with AD. Together, the present system pharmacology and in silico findings demonstrate that curcumin might play a significant role in modulating AD-pathobiology, supporting its therapeutic application for the prevention and treatment of AD.
REVIEW | doi:10.20944/preprints202308.1976.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: salt; sodium; urinary sodium; spot urine; 24-hr urine; South Asia
Online: 29 August 2023 (11:00:41 CEST)
According to WHO, reducing salt intake to less than 5 g/day means less death, disability, and suffering from heart disease and stroke, with around 1.89 million lives saved every year. In this scoping review, we have reviewed the salt consumption pattern of South Asia. For this purpose, we searched online databases and websites and consulted key informants to address relevant unpublished reports. The inclusion criteria are English-language publications between January 2011 and October 2021, as well as research that evaluated salt intake in the South Asian region and reported salt/sodium 24-hr urine or spot urine samples involving at least 100 participants. A total of 2043 studies were screened, out of which 12 studies fulfilled all the criteria. Our review revealed that reported salt intake in the South Asian region ranges from 6.7-13.3 g/day, which was higher than the WHO-recommended maximum level of 5 g/day in all countries. Men consumed more salt than women. This review demonstrates the critical importance of implementing a salt reduction program in South Asian countries.
ARTICLE | doi:10.20944/preprints202202.0028.v1
Subject: Social Sciences, Psychology Keywords: social media; addiction; anxiety; fear; health issues
Online: 2 February 2022 (10:53:03 CET)
Social media addiction has attracted the attention of researchers especially during the COVID era because negative emotions generated from the pandemic may have increased social media addiction. The present study aimed to investigate the role of negative emotions and social media addiction on health problems during and after the COVID lockdown. A survey was conducted with 2926 participants aged between 25 and 45 years. The data collection period was between 2nd September and 13th October 2020. Partial Least Square Structural Equation Modeling was conducted for data analysis by controlling the respondents' working time, leisure time, gender, education, and age. Our study showed that social media addiction and time spent on social media impact health. Interestingly, while anxiety about COVID increased social media addiction, fear about COIVD reduced social media addiction. Also, long working hours contributed most to people’s health issues, and its impact on social media addiction and hours was much higher than negative emotions, where males faced more health challenges than females. The impacts of negative emotions generated by the COVID on social media addiction and health issues should be reconsidered. Government and employers' control of people's working time stress should prioritize solving social media addiction-related issues.
ARTICLE | doi:10.20944/preprints202007.0054.v1
Subject: Social Sciences, Cognitive Science Keywords: COVID-19; Knowledge; Perception of Risk; Pandemic Outbreak; Disease Control; Cross-sectional Study
Online: 5 July 2020 (08:10:36 CEST)
COVID-19 is an infectious disease spreading through human touch. This study explored the risk perception and knowledge towards COVID-19 infection among Bangladeshi adult participants. Two self-administered online surveys were administered at two different time points from 26-31 March 2020 (Early lockdown) and 11-16 May 2020 (Late lockdown) through social media on 1005 respondents (322 and 683 participants, respectively) during COVID-19 lockdown period in Bangladesh. Univariate and multiple linear regression models were used to examine factors associated with risk perception and knowledge towards COVID-19. The mean knowledge (8.4 vs. 8.1, P=0.022) and risk perception (11.2 vs. 10.6, P < 0.001) scores differ significantly between early and late lockdown. Compared to the early lockdown period, the scores for perceived risk of contracting COVID-19 decreased significantly while public knowledge about COVID-19 was lower but not statistically significant. Female participants who practiced high quarantine particularly those who did so at the public health order during the lockdown reported increased knowledge towards the spread of COVID-19 and perceived high risk of contracting COVID-19. Education intervention using awareness to increase public knowledge and perception towards COVID-19 in Bangladesh should target male participants who practiced low quarantine and are less worried about the spread of such novel coronavirus even as the physical distancing persists.
REVIEW | doi:10.20944/preprints202005.0342.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: seaweed; metabolites; neuroprotection; Alzheimer’s disease; Parkinson’s disease; ischemic stroke; computer-aided drug discovery
Online: 21 May 2020 (09:49:29 CEST)
Beyond their significant contribution to the dietary and industrial supplies, marine algae are considered to be a potential source of some unique metabolites with diverse health benefits. The pharmacological properties, such as antioxidant, anti-inflammatory, cholesterol homeostasis, protein clearance and anti-amyloidogenic potentials of algal metabolites endorse their protective efficacy against oxidative stress, neuroinflammation, mitochondrial dysfunction, and impaired proteostasis which are known to be implicated in the pathophysiology of neurodegenerative disorders and the associated complications after cerebral ischemia and brain injuries. As was evident in various preclinical studies, algal compounds conferred neuroprotection against a wide range of neurotoxic stressors, such as oxygen/glucose deprivation, hydrogen peroxide, glutamate, amyloid β, or 1-methyl-4-phenylpyridinium (MPP+) and, therefore, hold therapeutic promise for brain disorders. While a significant number of algal compounds with promising neuroprotective capacity have been identified over the last decades, a few of them have had access to clinical trials. However, the recent approval of an algal oligosaccharide, sodium oligomannate, for the treatment of Alzheimer's disease enlightened the future of marine algae-based drug discovery. In this review, we briefly outline the pathophysiology of neurodegenerative diseases and brain injuries for identifying the targets of pharmacological intervention, and then review the literature on the neuroprotective potentials of algal compounds along with the underlying pharmacological mechanism, and present an appraisal on the recent therapeutic advances. We also propose a rational strategy to facilitate algal metabolites-based drug development.
ARTICLE | doi:10.20944/preprints202001.0153.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: antioxidant system; chilling stress; mineral homeostasis; nitric oxide; oxidative stress; rice
Online: 15 January 2020 (12:32:41 CET)
Being a chilling-sensitive staple crop, rice (Oryza sativa L.) is vulnerable to climate change. The competence of rice to withstand chilling stress should, therefore, be enhanced through technological tools. The present study employed chemical intervention like application of sodium nitroprusside (SNP) as nitric oxide (NO) donor and elucidated the underlying molecular mechanisms of NO-mediated chilling tolerance in rice. At germination stage, germination indicators were interrupted by chilling stress (5.0 ± 1.0°C for 8 h day‒1), while pretreatment with 100 μM SNP markedly improved the indicators. At seedling stage (14-day-old), chilling stress caused stunted growth with visible toxicity along with alteration of biochemical markers, for example, increase in oxidative stress markers (superoxide, hydrogen peroxide, and malondialdehyde) and osmolytes (total soluble sugar; proline and soluble protein content, SPC), and decrease in chlorophyll (Chl), relative water content (RWC), and antioxidants. However, NO application attenuated toxicity symptoms with improving growth performance which might be attributed to enhanced activities of antioxidants, mineral contents, Chl, RWC and SPC. Furthermore, principal component analysis indicated that water imbalance and increased oxidative damage were the main contributors to chilling injury, whereas NO-mediated mineral homeostasis and antioxidant defense were the critical determinants for chilling tolerance in rice. Collectively, our findings revealed that NO protects against chilling stress through valorizing cellular defense mechanisms, suggesting that exogenous application of NO could be a potential tool to evolve cold tolerance as well as climate resilience in rice.
REVIEW | doi:10.20944/preprints202109.0123.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Genistein; Estrogen receptor; BRCA-1; Cell cycle; Tumor suppressor gene; Molecular pharmacology; Synergistic activity.
Online: 7 September 2021 (11:59:15 CEST)
Breast cancer (BC) is the most common type of cancer in both men and women alike, but it is more prevalent in women. Natural compounds that can modulate the oncogenic process can be considered a significant anti-cancer agent for treating BC. These natural compounds are more effective than synthetic drugs, which have profound side effects on the normal cell and resistance to cancer cells. Genistein is a type of dietary phytoestrogen included in the flavonoid group with a similar structure of estrogen that might provide a strong alternative and complementary medicine to existing chemotherapeutics drugs. Several research studies demonstrated that it can target the estrogen receptor (ER), Human epidermal growth factor receptor-2 (HER2), and Breast cancer gene-1 (BRCA-1) in multiple BC cell lines, as well as sensitize cancer cell lines to this compound when used at an optimal inhibitory concentration. Genistein effectively showed anti-cancer activities through apoptosis induction, arresting cell cycle, inhibiting angiogenesis with metastasis, reducing inflammation, mammosphere formation, tumor growth, up-regulating tumor suppressor gene, and downregulating oncogene in suppressing cancer progression in vitro and animal model study. In addition, research studies have also suggested that these phytochemicals synergistically reverse the resistance mechanism of chemotherapeutic drugs, increasing the efficacy of some chemoinformatics drugs. Our review article aims to unbox and validate the molecular pharmacology in breast tissue, cell-specific anti-cancer mechanism with synergistic activity, and possible pharmacokinetic parameters of Genistein as a potential alternative therapeutic option for the treatment of BC.