283 research outputs found
Deep Learning Approach to Improve Spatial Resolution of GOES-17 Wildfire Boundaries using VIIRS Satellite Data
The rising severity and frequency of wildfires in recent years in the U.S. have raised numerous concerns regarding the improvement in wildfire emergency response management and decision-making systems, which require operational high temporal and spatial resolution monitoring capabilities. Satellites are one of the tools that can be used for wildfire monitoring. However, none of the currently available satellites provide both high temporal and spatial resolution. For example, GOES-17 geostationary satellite has a high temporal (5 min) but a low spatial resolution (2 km), and VIIRS polar orbiter satellite has a low temporal (~12 h) but high spatial resolution (375 m). This study aims to leverage currently available satellite data sources, such as GOES and VIIRS, along with Deep Learning (DL) advances to achieve an operational high-resolution wildfire monitoring tool.This study considers the problem of increasing the spatial resolution of low resolution satellite data using high resolution satellite. An Autoencoder DL model is proposed to learn how to map GOES-17 geostationary low spatial resolution satellite images to VIIRS polar orbiter high spatial resolution satellite images. In this context, several loss functions and architectures are implemented and tested to predict both the area of fire and corresponding fire radiance values. These models are trained and tested on wildfire sites from 2019 to 2021 in the western U.S. The results indicate that DL models can improve the spatial resolution of GOES-17 images, leading to images that mimic the spatial resolution of VIIRS images. Combined with GOES-17 higher temporal resolution, the DL model can provide high-resolution near-real-time wildfire monitoring capability as well as semi-continuous wildfire progression maps
Novel Interaction, Regulation of Phosphorylation and Mitotic Localization of Cell Division Cycle Associated Protein 7 (CDCA7)
Cell Division Cycle Associated Protein 7 (CDCA7) is a novel protein with poorly defined physiological significance. The proximity labeling method known as Biotin Identification (BioID) was used to determine candidate interactors of CDCA7. Mass spectrometry identified the microtubule spindle assembly protein TPX2 as a novel candidate interactor of CDCA7. Immunoprecipitation experiments verified interaction between CDCA7 and TPX2. The region of interaction was isolated to residues 195-204 of CDCA7. Based on inhibitor experiments, Aurora A kinase activity coincides with the phosphorylation of CDCA7 at the threonine (T) 163 residue. During mitosis, CDCA7 colocalizes with TPX2, localizes at centrosomes and undergoes phosphorylation at T163. These findings and previous findings in literature place CDCA7, TPX2 and potentially Aurora A kinase together within the context of mitosis. The results here demonstrate the direct interaction between CDCA7 and TPX2, and highlight residue T163 of CDCA7 as a prospective phosphorylation target of Aurora A kinase
Dose Optimization of Chloroquine by Pharmacokinetic Modeling During Pregnancy for the Treatment of Zika Virus Infection
The insidious nature of Zika virus (ZIKV) infections can have a devastating consequence for foetal development. Recent reports have highlighted that chloroquine (CQ) is capable of inhibiting ZIKV endocytosis in brain cells. We applied pharmacokinetic modelling to develop a predictive model for CQ exposure to identify an optimal maternal/foetal dosing regimen to prevent ZIKV endocytosis in brain cells. Model validation utilised 13 non-pregnancy and 3 pregnancy clinical studies and a therapeutic CQ plasma window of 0.3-2 μM was derived. Dosing regimens used in rheumatoid arthritis, systemic lupus erythematosus and malaria were assessed for their ability to target this window. Dosing regimen identified that weekly doses used in malaria were not sufficient to reach the lower therapeutic window, however daily doses of 150 mg achieved this therapeutic window. The impact of gestational age was further assessed and culminated in a final proposed regimen of 600 mg on day 1, 300 mg on day 2 and 3 and 150 mg thereafter until the end of trimester 2, which resulted in maintaining 65 % and 94 % of subjects with a trough plasma concentration above the lower therapeutic window on day 6 and at term, respectively
Phytochemical mediated-modulation of the expression and transporter function of breast cancer resistance protein at the blood-brain barrier:an in-vitro study
Clinical translation of BCRP inhibitors have failed due to neurotoxicity and novel approaches are required to identify suitable modulators of BCRP to enhance CNS drug delivery. In this study we examine 18 compounds, primarily phytochemicals, as potential novel modulators of AhR-mediated regulation of BCRP expression and function in immortalised and primary porcine brain microvascular endothelial cells as a mechanism to enhance CNS drug delivery. The majority of modulators possessed a cellular viability IC50 > 100 µM in both cell systems. BCRP activity, when exposed to modulators for 1 hour, was diminished for most modulators through significant increases in H33342 accumulation at < 10 µM with 2,6,4-trimethoflavone increasing H33342 intracellular accumulation by 3.7–6.6 fold over 1–100 µM. Western blotting and qPCR identified two inducers of BCRP (quercetin and naringin) and two down-regulators (17-β-estradiol and curcumin) with associated changes in BCRP efflux transport function further confirmed in both cell lines. siRNA downregulation of AhR resulted in a 1.75 ± 0.08 fold change in BCRP expression, confirming the role of AhR in the regulation of BCRP. These findings establish the regulatory role AhR of in controlling BCRP expression at the BBB and confirm quercetin, naringin, 17-β-estradiol, and curcumin as novel inducers and down-regulators of BCRP gene, protein expression and functional transporter activity and hence potential novel target sites and candidates for enhancing CNS drug delivery
A dynamic perfusion based blood-brain barrier model for cytotoxicity testing and drug permeation
The blood-brain barrier (BBB) serves to protect and regulate the CNS microenvironment. The development of an in-vitro mimic of the BBB requires recapitulating the correct phenotype of the in-vivo BBB, particularly for drug permeation studies. However the majority of widely used BBB models demonstrate low transendothelial electrical resistance (TEER) and poor BBB phenotype. The application of shear stress is known to enhance tight junction formation and hence improve the barrier function. We utilised a high TEER primary porcine brain microvascular endothelial cell (PBMEC) culture to assess the impact of shear stress on barrier formation using the Kirkstall QuasiVivo 600 (QV600) multi-chamber perfusion system. The application of shear stress resulted in a reorientation and enhancement of tight junction formation on both coverslip and permeable inserts, in addition to enhancing and maintaining TEER for longer, when compared to static conditions. Furthermore, the functional consequences of this was demonstrated with the reduction in flux of mitoxantrone across PBMEC monolayers. The QV600 perfusion system may service as a viable tool to enhance and maintain the high TEER PBMEC system for use in in-vitro BBB models
Development and Evaluation of a Novel Intranasal Spray for the Delivery of Amantadine
The aim of this study was to develop and characterise an intranasal delivery system for amantadine (AMT). Optimal formulations (F) consisted of a thermosensitive polymer Pluronic® 127 (P127) and either carboxy methyl cellulose (CMC) or chitosan (CS) which demonstrated gel-transition at nasal cavity temperatures (34 °C ± 1 °C). Rheologically, the loss tangent (Tan δ) confirmed a three-stage gelation phenomena at 34 °C ± 1 °C and non-Newtonian behaviour. Storage of FCMC and FCS at 4 °C for 8 weeks resulted in repeatable release profiles at 34 °C when sampled, with a Fickian mechanism earlier on but moving towards anomalous transport by week 8. Polymers (P127, CMC and CS) demonstrated no significant cellular toxicity to human nasal epithelial cells up to 4 mg/mL and up to 1 mM for AMT (IC50: 4.5 mM ± 0.05 mM). FCMC and FCS demonstrated slower release across an in-vitro human nasal airway model (43-44 % vs 79 % ± 4.58 % for AMT). Using a human nasal cast model, deposition into the olfactory regions (potential nose-to-brain) was demonstrated upon nozzle insertion (5 mm) whereas tilting of the head forward (15°) resulted in greater deposition in the bulk of the nasal cavity
The impact of CYP2B6 polymorphisms on the interactions of efavirenz with lumefantrine:Implications for paediatric antimalarial therapy
Lumefantrine is a widely used antimalarial in children in sub-Saharan Africa and is predominantly metabolised by CYP3A4. The concomitant use of lumefantrine with the antiretroviral efavirenz, which is metabolised by CYP2B6 and is an inducer of CYP3A4, increases the risk of lumefantrine failure and can result in an increased recrudescence rate in HIV-infected children. This is further confounded by CYP2B6 being highly polymorphic resulting in a 2–3 fold higher efavirenz plasma concentration in polymorphic subjects, which enhances the potential for an efavirenz-lumefantrine drug-drug interaction (DDI). This study developed a population-based PBPK model capable of predicting the impact of efavirenz-mediated DDIs on lumefantrine pharmacokinetics in African paediatric population groups, which also considered the polymorphic nature of CYP2B6. The validated model demonstrated a significant difference in lumefantrine target day 7 concentrations (Cd7) in the presence and absence of efavirenz and confirmed the capability of efavirenz to initiate this DDI. This was more apparent in the *6/*6 compared to *1/*1 population group and resulted in a significantly lower (P < 0.001) lumefantrine Cd7. A prospective change in dosing schedule from 3-days to 7-days resulted in a greater number of *6/*6 subjects (28–57%) attaining the target Cd7 across age bands (0.25–13 years), with the greatest increase evident in the 1–4 year old group (3-day: 1%; 7-day: 28%)
Phytoestrogens modulate breast cancer resistance protein expression and function at the blood-cerebrospinal fluid barrier
PURPOSE: Breast cancer resistance protein (BCRP/ABCG2) is a drug efflux transporter expressed at the blood cerebrospinal fluid barrier (BCSFB), and influences distribution of drugs into the central nervous systems (CNS). Current inhibitors have failed clinically due to neurotoxicity. Novel approaches are needed to identify new modulators to enhance CNS delivery. This study examines 18 compounds (mainly phytoestrogens) as modulators of the expression/function of BCRP in an in vitro rat choroid plexus BCSFB model. METHODS: Modulators were initially subject to cytotoxicity (MTT) assessment to determine optimal non-toxic concentrations. Reverse-transcriptase PCR and confocal microscopy were used to identify the presence of BCRP in Z310 cells. Thereafter modulation of the intracellular accumulation of the fluorescent BCRP probe substrate Hoechst 33342 (H33342), changes in protein expression of BCRP (western blotting) and the functional activity of BCRP (membrane insert model) were assessed under modulator exposure. RESULTS: A 24 hour cytotoxicity assay (0.001 µM-1000 µM) demonstrated the majority of modulators possessed a cellular viability IC50 > 148 µM. Intracellular accumulation of H33342 was significantly increased in the presence of the known BCRP inhibitor Ko143 and, following a 24 hour pre-incubation, all modulators demonstrated statistically significant increases in H33342 accumulation (P < 0.001), when compared to control and Ko143. After a 24 hour pre-incubation with modulators alone, a 0.16-2.5-fold change in BCRP expression was observed for test compounds. The functional consequences of this were confirmed in a permeable insert model of the BCSFB which demonstrated that 17-β-estradiol, naringin and silymarin (down-regulators) and baicalin (up-regulator) can modulate BCRP-mediated transport function at the BCSFB. CONCLUSION: We have successfully confirmed the gene and protein expression of BCRP in Z310 cells and demonstrated the potential for phytoestrogen modulators to influence the functionality of BCRP at the BCSFB and thereby potentially allowing manipulation of CNS drug disposition
Exploration of Effective Spatial Performance of Accessible Neighbourhood Green (Ang), Including its Proportion and Standard Distance from User in Dhanmondi Residential Area, Dhaka
Urban physical context can be analyzed across three key matrixes (3-P) among others i.e. place, path, and people. So, pragmatic analysis of spatial effective performances connecting 3-P, require provoking frequency of people’s experience. Acknowledging this issue, the demand for accessible neighbourhood green (ANG) at an appropriate distance becomes the primary concern to enhance the quality of life and liveability in a city. However, with the continued urban growth and densification, the discrepancy between the demand and supply of open space continues to vary requiring adjustments to remain responsive. The real-life circumstance results in a shortage of parks and open areas in terms of demand and supply within accessible distance in Dhaka city. This paper intends to examine this issue through the case of the planned Dhanmondi Residential Area (DRA) in Dhaka. Despite having provision of multiple open spaces in DRA, visitor’s frequency varies due to age and gender group accessibility conditions and varying distances. Considering existing spatial norms set by Detail Area Plan (DAP), Dhaka structure plan (DSP), and numerous research works on Dhaka open spaces, the major inquiry posed here is whether these open spaces are appropriate for DRA or not. Therefore, the objective of this paper focuses on examining the quality of the physical environment of Neighbourhood public open spaces termed here as accessible neighbourhood green (ANG) in DRA to examine their adequacy concerning proportion and distance synchronized with the frequency of visits. The initial part of the paper focuses on conceptualizing the problem vis-à -vis the existing scenario. Surveys and interviews have been conducted to assess people’s perceptions in terms of comfort, accessibility, sociability, and user frequency aligned with proximity. The result indicates that the provision of one appropriate ANG within two or three standard blocks apart contribute to enhancing the quality of life for the city dwellers and their liveability
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