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Fulltext Bandwidth enhancement of a dual band planar monopole antenna using meandered microstrip feeding

Ahsan MR, Islam MT, Habib Ullah M, Misran N

ScientificWorldJournal, 2014;2014:856504.
PMID: 24723832 DOI: 10.1155/2014/856504

A meandered-microstrip fed circular shaped monopole antenna loaded with vertical slots on a high dielectric material substrate (ε r = 15) is proposed in this paper. The performance criteria of the proposed antenna have been experimentally verified by fabricating a printed prototype. The experimental results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing meandered-microstrip feeding in assistant of partial ground plane. It is observed that, the -10 dB impedance bandwidth of the proposed antenna at lower band is 44.4% (600 MHz-1 GHz) and at upper band is 28% (2.25 GHz-2.95 GHz). The measured maximum gains of -1.18 dBi and 4.87 dBi with maximum radiation efficiencies have been observed at lower band and upper band, respectively. The antenna configuration and parametric study have been carried out with the help of commercially available computer-aided EM simulator, and a good accordance is perceived in between the simulated and measured results. The analysis of performance criteria and almost consistent radiation pattern make the proposed antenna a suitable candidate for UHF RFID, WiMAX, and WLAN applications.
Personal health records: retrieving contextual information with Google Custom Search

Ahsan M, Seldon HL, Sayeed S

Stud Health Technol Inform, 2012;182:10-8.
PMID: 23138074

Ubiquitous personal health records, which can accompany a person everywhere, are a necessary requirement for ubiquitous healthcare. Contextual information related to health events is important for the diagnosis and treatment of disease and for the maintenance of good health, yet it is seldom recorded in a health record. We describe a dual cellphone-and-Web-based personal health record system which can include 'external' contextual information. Much contextual information is available on the Internet and we can use ontologies to help identify relevant sites and information. But a search engine is required to retrieve information from the Web and developing a customized search engine is beyond our scope, so we can use Google Custom Search API Web service to get contextual data. In this paper we describe a framework which combines a health-and-environment 'knowledge base' or ontology with the Google Custom Search API to retrieve relevant contextual information related to entries in a ubiquitous personal health record.
Fulltext Support vector data description with kernel density estimation (SVDD-KDE) control chart for network intrusion monitoring

Ahsan M, Khusna H, Wibawati, Lee MH

Sci Rep, 2023 Nov 06;13(1):19149.
PMID: 37932421 DOI: 10.1038/s41598-023-46719-3

Multivariate control charts have been applied in many sectors. One of the sectors that employ this method is network intrusion detection. However, the issue arises when the conventional control chart faces difficulty monitoring the network-traffic data that do not follow a normal distribution as required. Consequently, more false alarms will be found when inspecting network traffic data. To settle this problem, support vector data description (SVDD) is suggested. The control chart based on the SVDD distance can be applied for the non-normal distribution, even the unknown distributions. Kernel density estimation (KDE) is the nonparametric approach that can be applied in estimating the control limit of the non-parametric control charts. Based on these facts, a multivariate chart based on the integrated SVDD and KDE (SVDD-KDE) is proposed to monitor the network's anomaly. Simulation using the synthetic dataset is performed to examine the performance of the SVDD-KDE chart in detecting multivariate data shifts and outliers. Based on the simulation results, the proposed method produces better performance in detecting shifts and higher accuracy in detecting outliers. Further, the proposed method is applied in the intrusion detection system (IDS) to monitor network attacks. The NSL-KDD data is analyzed as the benchmark dataset. A comparison between the SVDD-KDE chart with the other IDS-based-control chart and the machine learning algorithms is executed. Although the it has high computational cost, the results show that the IDS based on the SVDD-KDE chart produces a high accuracy at 0.917 and AUC at 0.915 with a low false positive rate compared to several algorithms.
Fulltext Comparison of 3D Hip Joint Kinematics in People with Asymptomatic Pronation of the Foot and Non-Pronation Controls

Alahmri F, Alsaadi S, Ahsan M

Malays J Med Sci, 2021 Jun;28(3):77-85.
PMID: 34285646 DOI: 10.21315/mjms2021.28.3.7

Background: The impact of asymptomatic pronation on proximal joints during motion has not been well understood, and research on it remains limited. Therefore, the current study determines the effect of asymptomatic pronation of the foot on hip joint kinematics during gait.
Methods: Forty participants were recruited for the study (20 with asymptomatic pronated feet and 20 with non-pronated feet). Foot assessment was conducted by navicular drop and rear-foot angle tests. Hip joint kinematics were measured via MVN Xsens system 3D-motion capture from sagittal, frontal and transverse planes during gait. An independent t-test was used to identify differences in kinematic variables.
Results: Both groups were similar in characteristics, and there were no significant differences between the groups in age (P = 0.674) and BMI (P = 0.459). However, there was a significant difference in arch height (P = 0.001) and rear-foot angle (P = 0.001). Our findings showed there were insignificant differences between the asymptomatic pronated foot and non-pronated foot control groups in hip joint kinematics of sagittal (P = 0.618), frontal (P = 0.276), and transverse (P = 0.337) planes during a full gait cycle.
Conclusion: Patients with asymptomatic pronation of the foot and non-pronation of the foot showed similar movement patterns of hip kinematics in all three planes. The findings of the present study highlight the need for clinicians to consider foot alignment when examining patients with asymptomatic pronation of the foot and non-pronation of the foot.
Fulltext Low-cost dielectric substrate for designing low profile multiband monopole microstrip antenna

Ahsan MR, Islam MT, Habib Ullah M, Arshad H, Mansor MF

ScientificWorldJournal, 2014;2014:183741.
PMID: 25136648 DOI: 10.1155/2014/183741

This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm(2) radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53-2.89 GHz) and 440 MHz (3.47-3.91 GHz) for WiMAX and 1550 MHz (6.28-7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively.
Review on diagnosis and molecular characterization of Toxoplasma gondii in humans and animals

Uddin AHMM, Hossain D, Ahsan MI, Atikuzzaman M, Karim MR

Trop Biomed, 2021 Dec 01;38(4):511-539.
PMID: 35001919 DOI: 10.47665/tb.38.4.091

Toxoplasma gondii is an obligate intracellular protozoon which causes toxoplasmosis, an important zoonotic disease that is endemic worldwide. Common sources of T. gondii infection in humans are food or water contaminated with oocysts and raw or undercooked meat with cysts. In animals, common sources of infection include feed, water, or litter contaminated with oocysts. The diagnosis and molecular characterization of T. gondii infection in humans and animals is crucial due to public and veterinary health importance. Various traditional and serological methods have been used in clinical practice for toxoplasmosis diagnosis, but interpreting the results remains a challenge. Several molecular techniques have also been used for the detection and genetic characterization of T. gondii , but primarily in research settings. In this paper, we review the techniques that are currently used for the diagnosis and genetic characterization of T. gondii in humans and animals, along with their advantages and disadvantages. The techniques reviewed have laid the groundwork for the future development of more effective and precise detection and characterization of T. gondii . These advances will contribute to a better understanding of epidemiology, prevention and control of toxoplasmosis. Thus, this review would be of particular interest to clinical physicians, veterinarians and researchers.
Performance of T2-based PCA mix control chart with KDE control limit for monitoring variable and attribute characteristics

Ahsan M, Mashuri M, Prastyo DD, Lee MH

Sci Rep, 2024 Mar 28;14(1):7372.
PMID: 38548881 DOI: 10.1038/s41598-024-58052-4

In this work, the mixed multivariate T2 control chart's detailed performance evaluation based on PCA mix is explored. The control limit of the proposed control chart is calculated using the kernel density approach. Through simulation studies, the proposed chart's performance is assessed in terms of its capacity to identify outliers and process shifts. When 30% more outliers are included in the data, the proposed chart provides a consistent accuracy rate for identifying mixed outliers. For the balanced percentage of attribute qualities, misdetection happens because of the high false alarm rate. For unbalanced attribute qualities and excessive proportions, the masking effect is the key issue. The proposed chart shows the improved performance for the shift in identifying the shift in the process.
Fulltext Cyclo-hexyl-ammonium nitrate

Bagabas AA, Aboud MF, Shemsi AM, Addurihem ES, Al-Othman ZA, Chidan Kumar CS, et al.

Acta Crystallogr Sect E Struct Rep Online, 2014 Mar 1;70(Pt 3):o253-4.
PMID: 24764971 DOI: 10.1107/S1600536814002244

In the title salt, C6H14N(+)·NO3 (-), the cyclo-hexyl ring adopts a chair conformation. The ammonium group occupies an equatorial position and the crystal struture is stabilized by inter-molecular N-H⋯O hydrogen-bonding inter-actions, resulting in a three-dimensional network.
Fulltext Compact double-p slotted inset-fed microstrip patch antenna on high dielectric substrate

Ahsan MR, Islam MT, Habib Ullah M, Mahadi WN, Latef TA

ScientificWorldJournal, 2014;2014:909854.
PMID: 25165750 DOI: 10.1155/2014/909854

This paper presents a compact sized inset-fed rectangular microstrip patch antenna embedded with double-P slots. The proposed antenna has been designed and fabricated on ceramic-PTFE composite material substrate of high dielectric constant value. The measurement results from the fabricated prototype of the antenna show -10 dB reflection coefficient bandwidths of 200 MHz and 300 MHz with center resonant frequency of 1.5 GHz and 4 GHz, respectively. The fabricated antenna has attained gains of 3.52 dBi with 81% radiation efficiency and 5.72 dBi with 87% radiation efficiency for lower band and upper band, respectively. The measured E- and H-plane radiation patterns are also presented for better understanding. Good agreement between the simulation and measurement results and consistent radiation patterns make the proposed antenna suitable for GPS and C-band applications.
Fulltext Performance Analysis of Blended Membranes of Cellulose Acetate with Variable Degree of Acetylation for CO2/CH4 Separation

Raza A, Farrukh S, Hussain A, Khan I, Othman MHD, Ahsan M

Membranes (Basel), 2021 Mar 29;11(4).
PMID: 33805339 DOI: 10.3390/membranes11040245

The separation and capture of CO2 have become an urgent and important agenda because of the CO2-induced global warming and the requirement of industrial products. Membrane-based technologies have proven to be a promising alternative for CO2 separations. To make the gas-separation membrane process more competitive, productive membrane with high gas permeability and high selectivity is crucial. Herein, we developed new cellulose triacetate (CTA) and cellulose diacetate (CDA) blended membranes for CO2 separations. The CTA and CDA blends were chosen because they have similar chemical structures, good separation performance, and its economical and green nature. The best position in Robeson's upper bound curve at 5 bar was obtained with the membrane containing 80 wt.% CTA and 20 wt.% CDA, which shows the CO2 permeability of 17.32 barrer and CO2/CH4 selectivity of 18.55. The membrane exhibits 98% enhancement in CO2/CH4 selectivity compared to neat membrane with only a slight reduction in CO2 permeability. The optimal membrane displays a plasticization pressure of 10.48 bar. The newly developed blended membranes show great potential for CO2 separations in the natural gas industry.
Fulltext Microwave-assisted Preparation of Cross-linked Gelatin-Paracetamol Matrices: Optimization Using the D-optimal Design

Kuang TK, Kang YB, Segarra I, Kanwal U, Ahsan M, Bukhari NI

Turk J Pharm Sci, 2021 04 20;18(2):167-175.
PMID: 33902255 DOI: 10.4274/tjps.galenos.2020.48902

Objectives: This study was conducted to assess the effect of microwave heating on the preparation of paracetamol cross-linked gelatin matrices by using the design of experiment (DoE) approach and explore the influence of the duration of microwave irradiation, the concentrations of crosslinker, and the amount of sodium bicarbonate (salt) on paracetamol release. These parameters were also compared with those of the matrices prepared via conventional heating.
Materials and Methods: Twenty gel matrices were prepared with different durations of microwave irradiation, amounts of maize, and concentrations of sodium bicarbonate as suggested by Design Expert (DX®). The percentage drug release, the coefficient of variance (CV) in release, and the mean dissolution time (MDT) were the properties explored in the designed experimentation.
Results: Target responses were dependent on microwave irradiation time, cross-linker amount, and salt concentration. Classical and microwave heating did not demonstrate statistically significant difference in modifying the percentage of drug released from the matrices. However, the CVs of microwave-assisted formulations were lower than those of the gel matrices prepared via classical heating. Thus, microwave heating produced lesser variations in drug release. The optimized gel matrices demonstrated that the observed percentage of drug release, CV, and MDT were within the prediction interval generated by DX®. The release mechanism of the matrix formulations followed the Peppas-Korsmeyer anomalous transport model.
Conclusion: The DoE-supported microwave-assisted approach could be applied to optimize the critical factors of drug release with less variation.
Fulltext Phytochemical and Biological Investigation of an Indigenous Plant of Bangladesh, Gynura procumbens (Lour.) Merr.: Drug Discovery from Nature

Jobaer MA, Ashrafi S, Ahsan M, Hasan CM, Rashid MA, Islam SN, et al.

Molecules, 2023 May 19;28(10).
PMID: 37241926 DOI: 10.3390/molecules28104186

Gynura procumbens (Lour.) Merr. (Family: Asteraceae) is a tropical Asian medicinal plant found in Thailand, China, Malaysia, Indonesia, and Vietnam. It has long been utilized to treat a variety of health concerns in numerous countries around the world, such as renal discomfort, constipation, diabetes mellitus, rheumatism, and hypertension. The chemical investigation resulted in the isolation and characterization of six compounds from the methanol (MeOH) extract of the leaves of Gynura procumbens, which were identified as phytol (1), lupeol (2), stigmasterol (3), friedelanol acetate (4), β-amyrin (5), and a mixture of stigmasterol and β-sitosterol (6). In-depth investigations of the high-resolution 1H NMR and 13C NMR spectroscopic data from the isolated compounds, along with comparisons to previously published data, were used to clarify their structures. Among these, the occurrence of Compounds 1 and 4 in this plant are reported for the first time. The crude methanolic extract (CME) and its different partitionates, i.e., petroleum ether (PESF), chloroform (CSF), ethyl acetate (EASF), and aqueous (AQSF) soluble fractions, were subjected to antioxidant, cytotoxic, thrombolytic, and anti-diabetic activities. In a DPPH free radical scavenging assay, EASF showed the maximum activity, with an IC50 value of 10.78 µg/mL. On the other hand, CSF displayed the highest cytotoxic effect with an LC50 value of 1.94 µg/mL compared to 0.464 µg/mL for vincristine sulphate. In a thrombolytic assay, the crude methanolic extract exhibited the highest activity (63.77%) compared to standard streptokinase (70.78%). During the assay for anti-diabetic activity, the PESF showed 70.37% of glucose-lowering activity, where standard glibenclamide showed 63.24% of glucose-reducing activity.
Fulltext Scientific basis for use of Pyrus pashia Buch.-Ham. ex D. Don. fruit in gastrointestinal, respiratory and cardiovascular ailments

Janbaz KH, Zaeem Ahsan M, Saqib F, Imran I, Zia-Ul-Haq M, Abid Rashid M, et al.

PLoS One, 2015;10(3):e0118605.
PMID: 25786248 DOI: 10.1371/journal.pone.0118605

Pyrus pashia Buch.-Ham. ex D. Don. has been used conventionally by many communities in the Himalayan region for the management of gastrointestinal, respiratory, and vascular complications. Set against this background, this study was carried out to justify the scientific basis to validate folkloric uses of fruits of Pyrus pashia Buch.-Ham. ex D. Don. (Pp.Cr) in traditional systems of medicine.

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