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Kawser Hossain, Mohammed,Abdal Dayem, Ahmed,Han, Jihae,Kumar Saha, Subbroto,Yang, Gwang-Mo,Choi, Hye Yeon,Cho, Ssang-Goo MDPI 2016 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.17 No.2
<P>Diabetes mellitus (DM) is a widespread metabolic disease with a progressive incidence of morbidity and mortality worldwide. Despite extensive research, treatment options for diabetic patients remains limited. Although significant challenges remain, induced pluripotent stem cells (iPSCs) have the capacity to differentiate into any cell type, including insulin-secreting pancreatic β cells, highlighting its potential as a treatment option for DM. Several iPSC lines have recently been derived from both diabetic and healthy donors. Using different reprogramming techniques, iPSCs were differentiated into insulin-secreting pancreatic βcells. Furthermore, diabetes patient-derived iPSCs (DiPSCs) are increasingly being used as a platform to perform cell-based drug screening in order to develop DiPSC-based cell therapies against DM. Toxicity and teratogenicity assays based on iPSC-derived cells can also provide additional information on safety before advancing drugs to clinical trials. In this review, we summarize recent advances in the development of techniques for differentiation of iPSCs or DiPSCs into insulin-secreting pancreatic β cells, their applications in drug screening, and their role in complementing and replacing animal testing in clinical use. Advances in iPSC technologies will provide new knowledge needed to develop patient-specific iPSC-based diabetic therapies.</P>
Antiviral Activity of 3,4'-Dihydroxyflavone on Influenza A Virus
Mohammed Kawser Hossain,최혜연,황재선,Ahmed Abdal Dayem,김정현,김영봉,부하령,조쌍구 한국미생물학회 2014 The journal of microbiology Vol.52 No.6
Influenza virus infection causes thousands of deaths and millionsof hospitalizations worldwide every year and the emergenceof resistance to anti-influenza drugs has promptedscientists to seek new natural antiviral materials. In this study,we screened 13 different flavonoids from various flavonoidgroups to identify the most potent antiviral flavonoid againsthuman influenza A/PR/8/34 (H1N1). The 3-hydroxyl groupflavonoids, including 3,2'-dihydroxyflavone (3,2'-DHF) and3,4 -dihydroxyflavone (3,4'-DHF), showed potent anti-influenzaactivity. They inhibited viral neuraminidase activityand viral adsorption onto cells. To confirm the anti-influenzaactivity of these flavonoids, we used an in vivo mousemodel. In mice infected with human influenza, oral administrationof 3,4'-DHF significantly decreased virus titers andpathological changes in the lung and reduced body weightloss and death. Our data suggest that 3-hydroxyl group flavonoids,particularly 3,4'-DHF, have potent antiviral activityagainst human influenza A/PR/8/34 (H1N1) in vitro and invivo. Further clinical studies are needed to investigate thetherapeutic and prophylactic potential of the 3-hydroxylgroup flavonoids in treating influenza pandemics.
Spline parameterization based nonlinear trajectory optimization along 4D waypoints
Ahmed, Kawser,Bousson, Kouamana,Coelho, Milca de Freitas Techno-Press 2019 Advances in aircraft and spacecraft science Vol.6 No.5
Flight trajectory optimization has become an important factor not only to reduce the operational costs (e.g.,, fuel and time related costs) of the airliners but also to reduce the environmental impact (e.g.,, emissions, contrails and noise etc.) caused by the airliners. So far, these factors have been dealt with in the context of 2D and 3D trajectory optimization, which are no longer efficient. Presently, the 4D trajectory optimization is required in order to cope with the current air traffic management (ATM). This study deals with a cubic spline approximation method for solving 4D trajectory optimization problem (TOP). The state vector, its time derivative and control vector are parameterized using cubic spline interpolation (CSI). Consequently, the objective function and constraints are expressed as functions of the value of state and control at the temporal nodes, this representation transforms the TOP into nonlinear programming problem (NLP). The proposed method is successfully applied to the generation of a minimum length optimal trajectories along 4D waypoints, where the method generated smooth 4D optimal trajectories with very accurate results.
Improvement in DRX Power Saving for Non-real-time Traffic in LTE
Mohammad Tawhid Kawser,Mohammad Rakibul Islam,Khondoker Ziaul Islam,Mohammad Atiqul Islam,Mohammad Mehadi Hassan,Zobayer Ahmed,Rafid Hasan 한국전자통신연구원 2016 ETRI Journal Vol.38 No.4
A discontinuous reception (DRX) operation is included in the Long Term Evolution (LTE) system to achieve power saving and prolonged battery life of the user equipment. An improvement in DRX power saving usually leads to a potential increase in the packet delay. An optimum DRX configuration depends on the current traffic, which is not easy to estimate accurately, particularly for non-real-time applications. In this paper, we propose a novel way to vary the DRX cycle length, avoiding a continuous estimation of the data traffic when only non-real-time applications are running with no active real-time applications. Because a small delay in non-real-time traffic does not essentially impact the user’s experience adversely, we deliberately allow a limited amount of delay in our proposal to attain a significant improvement in power saving. Our proposal also improves the delay in service resumption after a long period of inactivity. We use a stochastic analysis assuming an M/G/1 queue to validate this improvement.
Md. Yousuf Gazi,Tahrim Jannat Mowsumi,Md. Kawser Ahmed 한국해양과학기술원 2020 Ocean science journal Vol.55 No.3
Saint Martin's is a unique island located in the Bay of Bengal where coral species are abundant due to its favorable and unique environmental conditions. Coral communities are in great danger due to global climate change, direct commercial coral extraction and unplanned tourism around the island. The present study attempts to identify the coral zone and mapping of coral reefs from the period of 1980 to 2018. The study utilized five sets of multi-temporal Landsat satellite images to examine the changes of coral reefs in Saint Martin's Island during the study timeframe. Geospatial and image processing software was used for spatial coral colony mapping and data analysis. Satellite images processed to remove water depth impacts and supervised classification technique using the maximum likelihood decision rule suggested the spatial change of coral colonies over time. The result of the study indicates that coral colonies decreased steadily throughout the study period. A total area of 0.9342 km(2)of coral colonies disappeared during the study period from 1980 to 2018. Field observations around Saint Martin's Island indicates that destruction of coral reef habitat was basically caused by anthropogenic activities like tourism and extraction of coral by fisherman. Analysis of the historical data regarding tourism, population and households, and Sea Surface Temperature (SST) along with field observations of these parameter during 2018, suggests that anthropogenic factors are more significant than natural factors for causing coral reef degradation. It is very crucial to raise consciousness not only in the vicinity of Saint Martin's Island but more widely regarding the significance of the biodiversity of the Island.
Survey of nonlinear state estimation in aerospace systems with Gaussian priors
Coelho, Milca F.,Bousson, Kouamana,Ahmed, Kawser Techno-Press 2020 Advances in aircraft and spacecraft science Vol.7 No.6
Nonlinear state estimation is a desirable and required technique for many situations in engineering (e.g., aircraft/spacecraft tracking, space situational awareness, collision warning, radar tracking, etc.). Due to high standards on performance in these applications, in the last few decades, there was an increasing demand for methods that are able to provide more accurate results. However, because of the mathematical complexity introduced by the nonlinearities of the models, the nonlinear state estimation uses techniques that, in practice, are not so well-established which, leads to sub-optimal results. It is important to take into account that each method will have advantages and limitations when facing specific environments. The main objective of this paper is to provide a comprehensive overview and interpretation of the most well-known methods for nonlinear state estimation with Gaussian priors. In particular, the Kalman filtering methods: EKF (Extended Kalman Filter), UKF (Unscented Kalman Filter), CKF (Cubature Kalman Filter) and EnKF (Ensemble Kalman Filter) with an aerospace perspective.