Papers by Abdullah Mahmud
The Plasmodium falciparum-induced anion channel of human erythrocytes is an ATP-release pathway
Pflügers Archiv - European Journal of Physiology, 2009
Infection with the malaria parasite Plasmodium falciparum induces osmolyte and anion channels in ... more Infection with the malaria parasite Plasmodium falciparum induces osmolyte and anion channels in the host erythrocyte membrane involving ATP release and autocrine purinergic signaling. P. falciparum-parasitized but not unstimulated uninfected erythrocytes released ATP in a 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB; 7 microM)-sensitive and serum album (SA; 0.5% w/v)-stimulated manner. Since Plasmodium infection of human erythrocytes induces SA-dependent outwardly (OR) and SA-independent inwardly rectifying (IR) anion conductances, we tested whether the infection-induced OR channels directly generate an ATP release pathway. P. falciparum-parasitized erythrocytes were recorded in whole-cell mode with either Cl(-) or ATP as the only anion in the bath or pipette. In parasitized cells with predominant OR activity, replacement of bath NaCl by Na-ATP (NMDG-Cl pipette solution) shifted the current reversal potential (V (rev)) from -2 +/- 1 to +51 +/- 3 mV (n = 15). In cells with predominant IR activity, in contrast, the same maneuver induced a shift of V (rev) to significantly larger (p < or = 0.05, two-tailed t test) values (from -3 +/- 1 to +66 +/- 8 mV; n = 5) and an almost complete inhibition of outward current. The anion channel blocker NPPB reversibly decreased the ATP-generated OR currents from 1.1 +/- 0.1 nS to 0.2 +/- 0.05 nS and further shifted V (rev) to +87 +/- 7 mV (n = 12). The NPPB-sensitive fraction of the OR reversed at +48 +/- 4 mV suggesting a relative permeability of P (ATP)/P (Cl) approximately 0.01. Together, these data raise the possibility that the OR might be the electrophysiological correlate of an erythrocyte ATP release pathway.
The Plasmodium falciparum -induced anion channel of human erythrocytes is an ATP-release pathway
Pflugers Arch Eur J Physiol, 2009
Infection with the malaria parasite Plasmodium falciparum induces osmolyte and anion channels in ... more Infection with the malaria parasite Plasmodium falciparum induces osmolyte and anion channels in the host erythrocyte membrane involving ATP release and autocrine purinergic signaling. P. falciparum-parasitized but not unstimulated uninfected erythrocytes released ATP in a 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB; 7 microM)-sensitive and serum album (SA; 0.5% w/v)-stimulated manner. Since Plasmodium infection of human erythrocytes induces SA-dependent outwardly (OR) and SA-independent inwardly rectifying (IR) anion conductances, we tested whether the infection-induced OR channels directly generate an ATP release pathway. P. falciparum-parasitized erythrocytes were recorded in whole-cell mode with either Cl(-) or ATP as the only anion in the bath or pipette. In parasitized cells with predominant OR activity, replacement of bath NaCl by Na-ATP (NMDG-Cl pipette solution) shifted the current reversal potential (V (rev)) from -2 +/- 1 to +51 +/- 3 mV (n = 15). In cells with predominant IR activity, in contrast, the same maneuver induced a shift of V (rev) to significantly larger (p < or = 0.05, two-tailed t test) values (from -3 +/- 1 to +66 +/- 8 mV; n = 5) and an almost complete inhibition of outward current. The anion channel blocker NPPB reversibly decreased the ATP-generated OR currents from 1.1 +/- 0.1 nS to 0.2 +/- 0.05 nS and further shifted V (rev) to +87 +/- 7 mV (n = 12). The NPPB-sensitive fraction of the OR reversed at +48 +/- 4 mV suggesting a relative permeability of P (ATP)/P (Cl) approximately 0.01. Together, these data raise the possibility that the OR might be the electrophysiological correlate of an erythrocyte ATP release pathway.
Robots exhibit life-like behavior by performing intelligent actions. To enhance human-robot inter... more Robots exhibit life-like behavior by performing intelligent actions. To enhance human-robot interaction it is necessary to investigate and understand how end-users perceive such animate behavior. In this paper, we report an experiment to investigate how people perceived different designs of robot embodiments in terms of animacy and intelligence. iCat and Robovie II were used as the two embodiments in this experiment. We conducted a between-subject experiment where robot type was the independent variable, and perceived animacy and intelligence of the robot were the dependent variables. Our findings suggest that a robot's perceived intelligence is significantly correlated with animacy. The correlation between the intelligence and the animacy of a robot was observed to be stronger in the case of the iCat embodiment. Our results also indicate that the more animated the face of the robot, the more likely it is to attract the attention of a user. We also discuss the possible and probable explanations of the results obtained.
In this paper, we identify practical and technical issues that we experienced during designing an... more In this paper, we identify practical and technical issues that we experienced during designing and experimenting a location aware system. Our system was designed using the Spot location aware system and the Event Heap server under the TeamSpace framework. We conducted a series of test runs of the application with developers, using wireless mobile devices such as the HP IPAQ 5500. From our experience, it shows that currently the Spot system is not viable enough for designing an imminent location aware application. Finally, this paper concludes with general remarks about how our findings and recommendations can be taken into account for the improvement of the Spot system and consequently for similar location-aware systems.
Six grades of potato minitubers (<5 mm, 5-10 mm, 10-15 mm, 15-20 mm, 20-25 mm and > 25 mm) ... more Six grades of potato minitubers (<5 mm, 5-10 mm, 10-15 mm, 15-20 mm, 20-25 mm and > 25 mm) and four planting distance (25 cm, 20 cm, 15 cm and 10 cm) with a potato variety Diamant were taken in an study during 2013-14 at the Tuber Crops Research Centre of Bangladesh Agricultural Research Institute, Gazipur, Bangladesh. The objective was to observe the effect of minituber grades and planting distance on growth, seed yield, increase ratio and seed potential of potato. The largest minitubers (>25 mm) planted at widest distance (25 cm) produced maximum number of tubers per plant (18.7). The highest number of tubers per m 2 (306.7) was obtained with largest minitubers (>25 mm) planted at the closest plant spacing 10 cm, while it was lowest (64.0) in smallest size minituber (<5 mm) with the widest distance 25 cm. A significant increase ratio was found ranged from 14 (largest minituber with the closest planting distance) to 297 (smallest minituber with widest planting distan...
Dialogues on perception
The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Robot... more The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Robots exhibit life-like behavior by performing intelligent actions. To enhance human-robot interaction it is necessary to investigate and understand how end-users perceive such animate behavior. In this paper, we report an experiment to investigate how people perceived different designs of robot embodiments in terms of animacy and intelligence. iCat and Robovie II were used as the two embodiments in this experiment. We conducted a between-subject experiment where robot type was the independent variable, and perceived animacy and intelligence of the robot were the dependent variables. Our findings suggest that a robot’s perceived intelligence is significantly correlated with animacy. The correlation between the intelligence and the animacy of a robot was observed to be stronger in the case of the iCat embodiment. Our results also indicate that the more animated the face of the robot, the more...
A clonal seed orchard of Teak (Tectona grandis Linn. f.) consisting of 40 clones was established ... more A clonal seed orchard of Teak (Tectona grandis Linn. f.) consisting of 40 clones was established in 1982 at Kaptai Seed Orchard Centre of Karnafully Range, Chittagong Hill Tracts (South) Forest Division, Bangladesh with an aim of quality seed supply throughout the Bangladesh. The clones starts flowering at the age of 5. An assessment of fruiting potential of selected 20 clones of the orchard was done in November, 2012. An average of (0.11-3.50 kg) fruits/tree was produced by the clones. An average of 0.5 kg fruits/tree was collected from 60 ramets of 20 clones in February, 2012 to assess germination and initial growth behavior. From collected fruits, random 90 seeds/clone were used for germination test in the nursery of Institute of Forestry and Environmental Sciences of Chittagong University. The results reveal that seeds of clone 87 showed highest germination (42.22 %) and lowest germination (13.33%) was found for the clone 122. Highest seedling shoot length (20.73 cm), root lengt...
Proceedings of the 10th international conference on Human computer interaction with mobile devices and services - MobileHCI '08, 2008
In this paper we present an application that helps to motivate the elderly in maintaining an inde... more In this paper we present an application that helps to motivate the elderly in maintaining an independent healthy life style. With this application elderly people don't need to memorize the detailsthey will be informed round the clock about their diet and exercise schedules-freeing their memory for something else. The application was designed and implemented in a participatory manner. The early results from the evaluation show that the application has potential in enabling the elderly to maintain a healthy life style.
Proceedings of the 22nd …, 2008
In this paper we describe a user-centered approach to designing and evaluating a socially interac... more In this paper we describe a user-centered approach to designing and evaluating a socially interactive mobile game for the elderly. The objective of the game is to encourage the elderly to socially engage amongst themselves and to make the time that they spend in the community center more enjoyable. The design of the game, known as Walk 2 Win was done for and with the elderly. Two levels of the game (easy, difficult) across two modes (single, multi player) were evaluated with the elderly in a community center over two sessions. Our results show that senior citizens are keen to play simple games having uncomplicated rules as long as they can customize the game according to their whims. Their preference lies in playing games that are enhancements of existing games that they usually play. It was found that the elderly expressed a strong preference and interest to build a team, with for example their grand children. Additionally it was revealed that games for the elderly should incorporate everyone, regardless of gender or their role in the game. The methodological lessons that we came across throughout the design process are also presented.
Effect of weekly high-dose vitamin D3 supplementation on serum cholecalciferol concentrations in pregnant women
The Journal of Steroid Biochemistry and Molecular Biology, 2016
Vitamin D status is conventionally defined by the serum concentration of 25-hydroxyvitamin D. How... more Vitamin D status is conventionally defined by the serum concentration of 25-hydroxyvitamin D. However, it has been proposed that the serum cholecalciferol concentration (D3) also determines functional vitamin D sufficiency. The objective of this study was to describe the effect of weekly high-dose vitamin D3 supplementation on inter-dose serum D3 in pregnant women. We conducted a sub-study of a completed randomized double-blind placebo-controlled trial of vitamin D3 (35,000 IU/week) supplementation in late pregnancy (AViDD trial) in Dhaka, Bangladesh. This study included pregnant women enrolled at 26-29 weeks gestation who fully adhered to the prenatal supplement intervention for ≥8 consecutive weeks and for whom serum samples were available for D3 analysis (n=65). Serum D3 was uniformly low at enrolment. Mean D3 increased and was maximal at 1day after vitamin D dose administration (152.09 nmol/L, SD 25.11 nmol/L) and remained significantly higher in VitD vs. Pl at 7days (29.59 nmol/L vs. 1.92 nmol/L, p=0.007). Daily average of the group mean D3 during the week following dosing was 66.97 nmol/L in VitD versus 2.13 nmol/L in Pl. In conclusion, serum D3 remained significantly elevated throughout the week following ≥8 consecutive weekly doses of 35,000 IU D3 in pregnant women. However, the clinically significant minimum threshold of serum D3 remains to be established.
Perceived privacy handling in an amigo extended home environment application
Summary Perceived privacy ie, how users perceive that their privacy is handled by the system, is ... more Summary Perceived privacy ie, how users perceive that their privacy is handled by the system, is one of the key issues for the user acceptance of current ambient intelligent environment applications. This project was carried out in the context of the Amigo project, ...
Development of surface-anchored PLGA nanospheres with mannose-receptor ligands for targeting dendritic cells in cancer immunotherapy
Journal of Pharmacy and Pharmaceutical Sciences, 2008
Novel Poly(Ethylene Oxide)-Block-Poly(Ester) Block Copolymers
Chi 12 Extended Abstracts, 2012
In this paper we report the design of a communication system for people with aphasia. It consists... more In this paper we report the design of a communication system for people with aphasia. It consists of pairs of physical whiteboards that are connected over the internet. This allows users to combine any personal language skills with visuals and already existing materials at hand. The design has been based on feedback and evaluation sessions with aphasics and their therapists. The user test results show that the design provides a low entry barrier and enables relaxed conversations.
Prenatal vitamin D supplementation and infant vitamin D status in Bangladesh (256.4)
The Faseb Journal, Apr 1, 2014
International Journal of Pharmaceutics, 2008
Poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) and newly developed poly(ethylene oxi... more Poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) and newly developed poly(ethylene oxide)-block-poly(α-benzyl carboxylate ε-caprolactone) (PEO-b-PBCL) micelles were evaluated for the solubilization and delivery of cucurbitacin I and B, poorly water soluble inhibitors of signal transducer and activator of transcription 3 (STAT3). Encapsulation of cucurbitacins in PEO-b-PCL and PEO-b-PBCL by co-solvent evaporation technique resulted in polymeric micelles <90 nm in diameter. The aqueous solubility of both derivatives increased from less than 0.05 mg/mL in the absence of the copolymer to around 0.30-0.44 and 0.65-0.68 mg/mL in the presence of 5000-5000 and 5000-24,000 PEO-b-PCL micelles, respectively. Maximum cucurbitacin solubilization was achieved with PEO-b-PBCL micelles for both derivatives. PEO-b-PCL micelles having longer PCL block were found to be more efficient in sustaining the rate of release for cucurbitacins. The anticancer and STAT3 inhibitory activity of polymeric micellar cucurbitacins were comparable with free drugs in B16.F10 melanoma cell line in vitro. Intratumoral injection of 1 mg/kg/day cucurbitacin I resulted in the regression of established B16.F10 mouse melanoma tumors in vivo. In comparison to free cucurbitacin I, PEO-b-PBCL micellar cucurbitacin I was found to provide comparable anticancer effects against B16.F10 tumors and limit drug levels in animal serum while maintaining high drug levels in tumor following intratumoral administration. The results indicate the potential of polymeric micelles as suitable vehicles for the delivery of cucurbitacin-I and B. Compound Block copolymer Cucurbitacin loading ± S.D. (mg/mg) Encapsulation efficiency ± S.D. (%) Micellar size (nm) Polydispersity index
Molecular view modeling of atmospheric organic particulate matter: Incorporating molecular structure and co-condensation of water
Atmospheric Environment, 2015
Preference and Acceptability of Alternative Delivery Vehicles for Prenatal Calcium Supplementation among Pregnant Women in Urban Bangladesh
European Journal of Nutrition & Food Safety, 2015
Climate impacts on annual-average airborne particle source contributions in California
Geochmica et Cosmochimica Acta
Fundaments of Pharmaceutical Nanoscience - Polymersomes and Filomicelles
Amphiphilic block copolymers represent a major field of research in the design and creation of in... more Amphiphilic block copolymers represent a major field of research in the design and creation of innovative materials for biomedical applications. Self-directed assemblies of such copolymers have been of great value in the development of novel drug delivery systems. Polymeric vesicles (polymersomes) and worm-like micelles (or filomicelles) are particularly appealing due to their structure and composition that provides them with specific and tunable properties. The work reviewed at an introductory level in this chapter highlights some of the features of such aggregates and reviews the synthesis of their components, their assembly, and characterization. Degradation and drug release kinetics are described as well as their application in therapeutics.
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Papers by Abdullah Mahmud