Dynamic roles of angiopoietin-like proteins 1, 2, 3, 4, 6 and 7 in the survival and enhancement of ex vivo expansion of bone-marrow hematopoietic stem cells.

Akhter, Shahina,Rahman, Md Mashiar,Lee, Hyun Seo,Kim, Hyeon-Jin,Hong, Seong-Tshool Springer ; Higher Education Press 2013 Protein & cell Vol.4 No.3

<P>Recent advances in hematopoietic stem cells (HSCs) expansion by growth factors including angiopoietin-like proteins (Angptls) have opened up the possibility to use HSCs in regenerative medicine. However, the unavailability of true in vitro HSCs expansion by these growth factors has limited the understanding of the cellular and molecular mechanism of HSCs expansion. Here, we report the functional role of mouse Angptls 1, 2, 3, 4, 6 and 7 and growth factors SCF, TPO, IGF-2 and FGF-1 on purified mouse bone-marrow (BM) Lineage(-)Sca-1(+)(Lin-Sca-1(+)) HSCs. The recombinant retroviral transduced-CHO-S cells that secrete Angptls in serum-free medium were used alone or in combination with growth factors (SCF, TPO, IGF-2 and FGF-1). None of the Angptls stimulated HSC proliferation, enhanced or inhibited HSCs colony formation, but they did support the survival of HSCs. By contrast, any of the six Angptls together with saturating levels of growth factors dramatically stimulated a 3- to 4.5-fold net expansion of HSCs compared to stimulation with a combination of those growth factors alone. These findings lead to an understanding of the basic function of Angptls on signaling pathways for the survival as well as expansion of HSCs in the bone marrow niche.</P>

Performance Evaluation of the WiMAX Network under a Complete Partitioned User Group with a Traffic Shaping Algorithm

Akhter, Jesmin,Islam, Md. Imdadul,Amin, M.R. Korea Information Processing Society 2014 Journal of information processing systems Vol.10 No.4

To enhance the utilization of the traffic channels of a network (instead of allocating radio channel to an individual user), a channel or a group of channels are allocated to a user group. The idea behind this is the statistical distribution of traffic arrival rates and the service time for an individual user or a group of users. In this paper, we derive the blocking probability and throughput of a subscriber station of Worldwide Interoperability for Microwave Access (WiMAX) by considering both the connection level and packet-level traffic under a complete partition scheme. The main contribution of the paper is to incorporate the traffic shaping scheme onto the incoming turbulent traffic. Hence, we have also analyzed the impact of the drain rate of the buffer on the blocking probability and throughput.

Sectional image reconstruction and three-dimensional microscopy of small particles by angular spectrum method

Akhter, N.,Jung, H.C.,Kee, C.D.,Kim, K.S.,Choi, M.Y. Wissenschaftliche Verlagsgesellschaft m. b. H 2011 Optik Vol.122 No.14

In this letter, we demonstrate sectional image reconstruction and three-dimensional microscopy of small particles. We demonstrate sectional image reconstruction and holographic methods to obtain 2D and 3D images of small particles. A single hologram is sufficient to obtain a section containing only the focused parts of the reconstructed image. One can obtain images of different plane sections of a specimen in addition to its 3D display. The reconstruction of a digital hologram is based on the plane-wave expansion of the diffracted wave fields using Fourier optics (this method is also known as the angular spectrum method). With this method, the object-to-hologram distance can be quite small because the minimum-distance requirement does not apply. Furthermore, numerical reconstruction of transparent objects by this method may be interesting for micro-structure measurement.

Adaptive Pose Estimation for Gait Event Detection Using Context-Aware Model and Hierarchical Optimization

Akhter Israr,Jalal Ahmad,Kim Kibum 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5

To understand daily events accurately, adaptive pose estimation (APE) systems require a robust context-aware model and optimal feature selection methods. In this paper, we propose a novel gait event detection (GED) system that consists of saliency silhouette detection, a robust body parts model and a 2D stick-model followed by a hierarchical optimization algorithm. Furthermore, the most prominent context-aware features such as energy, 0–180° intensity and distinct moveable features are proposed by focusing on invariant and localized characteristics of human postures in diff erent event classes. Finally, we apply Grey Wolf optimization and a genetic algorithm to discriminate complex postures and to provide appropriate labels to each event. In order to evaluate the performance of proposed GED, two public benchmark datasets, UCF101 and YouTube, are examined via the n -fold cross validation method. For the two benchmark datasets, our proposed method detects the human body key points with 82.4% and 83.2% accuracy respectively. Also, it extracts the context-aware features and fi nally recognizes the gait events with 82.6% and 85.0% accuracy, respectively. Compared with other well-known statistical and state-of-the-art methods, our proposed method outperforms other similarly tasked methods in terms of posture detection and recognition accuracy.

Coping with Climate Change by Using Indigenous Knowledge of Ethnic Communities from in and around Lawachara National Park of Bangladesh

Akhter, Sayma,Raihan, Farzana,Sohel, Md. Shawkat Islam,Abu Syed, Md.,Das, Suman Kanti,Alamgir, Mohammed Institute of Forest Science 2013 Journal of Forest Science Vol.29 No.3

Climate change is considered to be one of the most serious threats and its impact is felt by the most vulnerable world's poorest countries including Bangladesh. In particular, ethnic communities, whose livelihoods depend on the use of natural resources, are likely to bear the brunt of adverse impacts. A case study was conducted in a fragile ecosystem of Lawachara national park of Bangladesh, to know the indigenous knowledge of the ethnic communities, how they adapt with the climate change impact by using indigenous knowledge. They use various IK to protect their crops from climate change impact. Thus, government should design policies which will be helpful to make them more resilience to face climate change impact.

Antioxidant activity of sea buckthorn (Hippophae rhamnoides) seed oil extracted using various organic solvents

Akhter Parveen,Bhatti Taseer Yasrab,Shafiq Iqrash,Jamil Farrukh,Nazar Rabia,Nazir Muhammad Shahid,Hassan Sadaf Ul,Hussain Murid,박영권 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.12

Sea buckthorn (SBT) combines very fascinating nutritional composition with vital vitamins (A, C, E, D, K, and B complexes). Flavonoids, sterols, α-carotene, linoleic acid, and many more unsaturated fatty acids are present in the sea buckthorn plant. The organic extract of SBT seeds is commonly utilized as an anti-aging ingredient in numerous cosmetics. SBT oil extracts are used in pharmaceuticals that treat diseases like diabetes, cancer, cardiovascular disease, and neurological disorders, in addition to cosmetology. In this investigation, various concentrations of organic solvents such as n-hexane, isopropyl alcohol, ethyl acetate, ethanol, methanol, and ascorbic acid (standard) were used for the extraction of oil from sea buckthorn seeds. The antioxidant activity of such extracts was checked by the iron chelating, commonly known as the ferric chloride (FeCl3) method, which is based on the ferric reducing ability of plasma (FRAP) assay with the help of UV-Vis. Our results indicate that seed extract of Hippophae rhamnoides, should be considered as a non-toxic source and the ferric reducing ability of plasma (FRAP) assay is used to evaluate the anti-oxidant potential by various organic solvents. The highest (68%) of FRAP is scavenged by the ethyl acetate and least (53%) of isopropyl extracts.

Endless Misery of Nimble Fingers : The Rana Plaza Disaster

AKHTER, Shamima 이화여자대학교 아시아여성학센터 2014 Asian Journal of Women's Studies(AJWS) Vol.20 No.1

In search of better luck and lives, poor women from rural Bangladesh come to urban areas of the country to work in the garments industry from which the country is earning the majority of its foreign income. The country’s fate is changing due to the industry; so is the fate of its owners, but the question is how much has the fate of the poor women who work in it changed? How empowered are these women as a result of their employment in the factories? Investigation has shown that women are victimized as a result of obvious gender discrimination. They become victims of any kind of disaster, including both human-made and natural. The disgraceful work environment has always pressured them into forced labor, often under threat and sometimes sexual harassment. The collapse of the eight-story Rana Plaza garment factory on April 24, 2013 has consequently caused another hidden disaster in women’s lives, the uncertainty of life in the future and post traumatic disorder. Economic access provided economic emancipation to some extent to these garment worker women. Paradoxically, the endless misery of women’s lives because of this human-made disaster is questioning the meaning of “women’s economic empowerment.”

A comparative study of reconstruction algorithms in digital holography

Akhter, N.,Min, G.,Kim, J.W.,Lee, B.H. Wissenschaftliche Verlagsgesellschaft m. b. H 2013 Optik Vol.124 No.17

Comparative studies of the different reconstruction algorithms in digital holography are presented. It shows that each method has different properties with respect to available reconstruction distances, resolution of reconstructed images and computational load. It is very important to choose an appropriate method for the reliable reconstruction in a given situation. Although the method based on Fresnel diffraction formula can still give an accurate reconstruction for smooth and slowly varying objects where the Fresnel approximation is not strictly satisfied, it cannot correctly reconstructed near wave-fields for more diffractive objects, where the higher-order terms in the expansion of the Fresnel approximation are more significant. Angular spectrum method can be a way out of those problems in Fresnel or convolution method, because of its validity for the closer region that the Fresnel region and is very useful for the measurement of microscopic samples requiring a high-numerical aperture imaging system as a necessity. We present one example of quantitative phase-contrast microscopy of small particles and its 3D prospective.

USE OF COW FAECES AT DIFFERENT TIMES AFTER BEING VOIDED AS A SOURCE OF MICRO-ORGANISMS IN IN VITRO DIGESTIBILITY ASSAYS OF FORAGES

Akhter, S.,Owen, E.,Hossain, M.M. Asian Australasian Association of Animal Productio 1996 Animal Bioscience Vol.9 No.4

Experiments were conducted to determine the effect of time intervals between collecting and use of cattle faeces as a source of micro-organisms in in vitro digestibility assays of forages. The results suggested that temperature conservation capacity by faeces depended on the size of the sample. There was no significant difference(p>0.05) between the first (T1 or 08:30 h) and second using time (T2 or 10:30 h). In vitro organic matter digestibility was significantly lower when faeces was used 5 h (T3 or 13:30 h) after collection. However, the organic matter digestibility determined at the second using time (T2) and third using time (T3) were highly correlated ($R^2=0.99$) with the first using time. It was concluded that faeces can be used as a source of microorganisms for in vitro digestibility assays of forages even 5 h after being voided.

Development of a Data Acquisition System for the Long-term Monitoring of Plum (Japanese apricot) Farm Environment and Soil

Akhter, Tangina,Ali, Mohammod,Cha, Jaeyoon,Park, Seong-Jin,Jang, Gyeang,Yang, Kyu-Won,Kim, Hyuck-Joo Korean Society for Agricultural Machinery 2018 바이오시스템공학 Vol.43 No.4

Purpose: To continuously monitor soil and climatic properties, a data acquisition system (DAQ) was developed and tested in plum farms (Gyewol-ri and Haechang-ri, Suncheon, Korea). Methods: The DAQ consisted of a Raspberry-Pi processor, a modem, and an ADC board with multiple sensors (soil moisture content (SEN0193), soil temperature (DS18B20), climatic temperature and humidity (DHT22), and rainfall gauge (TR-525M)). In the laboratory, various tests were conducted to calibrate SEN0193 at different soil moistures, soil temperatures, depths, and bulk densities. For performance comparison of the SEN0193 sensor, two commercial moisture sensors (SMS-BTA and WT-1000B) were tested in the field. The collected field data in Raspberry-Pi were transmitted and stored on a web server database through a commercial communications wireless network. Results: In laboratory tests, it was found that the SEN0193 sensor voltage reading increased significantly with an increase in soil bulk density. A linear calibration equation was developed between voltage and soil moisture content depending on the farm soil bulk density. In field tests, the SEN0193 sensor showed linearity (R = 0.76 and 0.73) between output voltage and moisture content; however, the other two sensors showed no linearity, indicating that site-specific calibration is important for accurate sensing. In the long-term monitoring results, it was observed that the measured climate temperature was almost the same as website information. Soil temperature information was higher than the values measured by DS18B20 during spring and summer. However, the local rainfall measured using TR 525M was significantly different from the values on the website. Conclusion: Based on the test results obtained using the developed monitoring system, it is thought that the measurement of various parameters using one device would be helpful in monitoring plum growth. Field data from the local farm monitoring system can be coupled with website information from the weather station and used more efficiently.