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Fulltext Optimal power flow using hybrid firefly and particle swarm optimization algorithm

Khan A, Hizam H, Bin Abdul Wahab NI, Lutfi Othman M

PLoS One, 2020;15(8):e0235668.
PMID: 32776932 DOI: 10.1371/journal.pone.0235668

In this paper, a novel, effective meta-heuristic, population-based Hybrid Firefly Particle Swarm Optimization (HFPSO) algorithm is applied to solve different non-linear and convex optimal power flow (OPF) problems. The HFPSO algorithm is a hybridization of the Firefly Optimization (FFO) and the Particle Swarm Optimization (PSO) technique, to enhance the exploration, exploitation strategies, and to speed up the convergence rate. In this work, five objective functions of OPF problems are studied to prove the strength of the proposed method: total generation cost minimization, voltage profile improvement, voltage stability enhancement, the transmission lines active power loss reductions, and the transmission lines reactive power loss reductions. The particular fitness function is chosen as a single objective based on control parameters. The proposed HFPSO technique is coded using MATLAB software and its effectiveness is tested on the standard IEEE 30-bus test system. The obtained results of the proposed algorithm are compared to simulated results of the original Particle Swarm Optimization (PSO) method and the present state-of-the-art optimization techniques. The comparison of optimum solutions reveals that the recommended method can generate optimum, feasible, global solutions with fast convergence and can also deal with the challenges and complexities of various OPF problems.
Multiple polypoid endometriosis--a rare complication following withdrawal of gonadotrophin releasing hormone (GnRH) agonist for severe endometriosis: a case report

Othman NH, Othman MS, Ismail AN, Mohammad NZ, Ismail Z

Aust N Z J Obstet Gynaecol, 1996 May;36(2):216-8.
PMID: 8798320

A 30-year old female who initially had typical endometriosis treated according to a standard regimen later developed numerous highly vascular endometrial polyps on the vagina, cervix, ureter, serosal surfaces of the uterus, pouch of Douglas (POD) and other areas of pelvic peritoneum as well as the endometrium 8 months after withdrawal of treatment with Zoladex gonadotrophin releasing hormone (GnRH) agonist used for treatment of this disease. We postulate that these polyps developed as a rebound phenomenon upon withdrawal of Zoladex. We believe this is the first report of this complication following use of GnRH analogue.
Fulltext Travelling Wave Pulse Coupled Oscillator (TWPCO) Using a Self-Organizing Scheme for Energy-Efficient Wireless Sensor Networks

Al-Mekhlafi ZG, Hanapi ZM, Othman M, Zukarnain ZA

PLoS One, 2017;12(1):e0167423.
PMID: 28056020 DOI: 10.1371/journal.pone.0167423

Recently, Pulse Coupled Oscillator (PCO)-based travelling waves have attracted substantial attention by researchers in wireless sensor network (WSN) synchronization. Because WSNs are generally artificial occurrences that mimic natural phenomena, the PCO utilizes firefly synchronization of attracting mating partners for modelling the WSN. However, given that sensor nodes are unable to receive messages while transmitting data packets (due to deafness), the PCO model may not be efficient for sensor network modelling. To overcome this limitation, this paper proposed a new scheme called the Travelling Wave Pulse Coupled Oscillator (TWPCO). For this, the study used a self-organizing scheme for energy-efficient WSNs that adopted travelling wave biologically inspired network systems based on phase locking of the PCO model to counteract deafness. From the simulation, it was found that the proposed TWPCO scheme attained a steady state after a number of cycles. It also showed superior performance compared to other mechanisms, with a reduction in the total energy consumption of 25%. The results showed that the performance improved by 13% in terms of data gathering. Based on the results, the proposed scheme avoids the deafness that occurs in the transmit state in WSNs and increases the data collection throughout the transmission states in WSNs.
Fulltext Understanding media literacy in relation to adolescent soft drink consumption behavior

Nur Nadirah MS, Ghazali H, Bakar AZA, Othman M

International Food Research Journal, 2016;23(1):381-388.
MyJurnal

This paper examines relationship between media literacy and the Theory of Planned Behavior (TPB) variables focusing on consumption of soft drink among adolescents in Klang Valley, Malaysia. In addition, this paper also determines soft drink consumption, level of media literacy and the influences of the TPB variables on the intention of soft drink consumption. A cluster sampling method was used in collecting data within the Klang Valley area. The sample consisted of 436 adolescents from secondary school, aged between 13 to 18 years old. Two main scales utilized were Media Literacy (ML) scale and TPB scale. The descriptive, multiple linear regression and Pearson product-moment correlation analyses were carried out to answer the research objectives. Results revealed that 36% of respondents drank a minimum of 1 can, bottle or glass of soft drink for the past seven days and possess good level of media literacy (35%). Meanwhile, 14% of variance in adolescents’ intention of soft drink consumption is explained by TPB variables. Additionally, the total media literacy score towards soft drink advertisement was significantly positively correlated with attitude (r = 0.250, p
Fulltext A Secure Region-Based Geographic Routing Protocol (SRBGR) for Wireless Sensor Networks

Adnan AI, Hanapi ZM, Othman M, Zukarnain ZA

PLoS One, 2017;12(1):e0170273.
PMID: 28121992 DOI: 10.1371/journal.pone.0170273

Due to the lack of dependency for routing initiation and an inadequate allocated sextant on responding messages, the secure geographic routing protocols for Wireless Sensor Networks (WSNs) have attracted considerable attention. However, the existing protocols are more likely to drop packets when legitimate nodes fail to respond to the routing initiation messages while attackers in the allocated sextant manage to respond. Furthermore, these protocols are designed with inefficient collection window and inadequate verification criteria which may lead to a high number of attacker selections. To prevent the failure to find an appropriate relay node and undesirable packet retransmission, this paper presents Secure Region-Based Geographic Routing Protocol (SRBGR) to increase the probability of selecting the appropriate relay node. By extending the allocated sextant and applying different message contention priorities more legitimate nodes can be admitted in the routing process. Moreover, the paper also proposed the bound collection window for a sufficient collection time and verification cost for both attacker identification and isolation. Extensive simulation experiments have been performed to evaluate the performance of the proposed protocol in comparison with other existing protocols. The results demonstrate that SRBGR increases network performance in terms of the packet delivery ratio and isolates attacks such as Sybil and Black hole.
STR data for the AmpFlSTR Profiler loci from the three main ethnic population groups (Malay, Chinese and Indian) in Malaysia

Lim KB, Jeevan NH, Jaya P, Othman MI, Lee YH

Forensic Sci Int, 2001 Jun 01;119(1):109-12.
PMID: 11348801

Allele frequencies for the nine STRs genetic loci included in the AmpFlSTR Profiler kit were obtained from samples of unrelated individuals comprising 139-156 Malays, 149-153 Chinese and 132-135 Indians, residing in Malaysia.
Determinants of smokeless tobacco use and prevalence among Sudanese adolescents

Othman M, Farid NDN, Aghamohammadi N, Danaee M

Arch Public Health, 2021 Oct 12;79(1):176.
PMID: 34641965 DOI: 10.1186/s13690-021-00699-w

BACKGROUND: Smokeless tobacco is a part of social and cultural life in Sudan. The affordability and availability of this kind of tobacco make it a fundamental issue in adolescents. The aim of this study is to investigate the extent of the use of smokeless tobacco in adolescents and its determinants.
METHODS: A school-based cross-sectional study was conducted in Khartoum state in Sudan. The study targeted male and female adolescents in secondary schools. A total of 3387 students from public and private schools participated in the study. Multistage random sampling was used to select the participants. The Arabic version questionnaire from the Global Youth Tobacco Survey (GYTS) was utilised to collect the data from the participants.
RESULTS: Among the participants, 57.3% were females and 42.7% were males. Students from private and public schools were 48.4 and 51.6%, respectively. The overall prevalence of those who had ever used smokeless tobacco was 7.6%, in which the prevalence among male students was 11.0% while among females was 5.0%. The determinant factors were male gender (OR 1.53 CI 95% 1.03-2.28), family structure (OR 1.52 CI 95% 1.03-2.23), exposure to second-hand smoke at home (OR 1.60 CI 95% 1.11-2.31), friends smoking cigarettes (OR 1.78 CI 95% 1.22-2.60), lack of restriction of selling tobacco to minors (OR 1.73 CI 95% 1.25-2.39), promotion of smokeless tobacco (OR 2.12 CI 95% 1.20-3.72) and low self-efficacy (OR 7.47 CI 95% 4.45-12.52).
CONCLUSION: A comprehensive prevention programme that enforces the prohibition of the promotion of smokeless tobacco and the selling of smokeless tobacco to minors is crucial. Moreover, the prevention programme should enhance adolescents' self-efficacy.
Idiopathic ileal volvulus with multiple concomitant infections in a starving man

Tan LJ, Othman MS, Hiu J, Wong KT, Lai SK

Malays J Pathol, 2021 Apr;43(1):81-85.
PMID: 33903310

BACKGROUND: Small bowel volvulus is defined as the torsion of the small intestine, potentially leading to bowel obstruction, gangrene and perforation. It is a rare condition, especially in adults.
CASE PRESENTATION: A 30-year-old man was retrieved from the jungle with severe weight loss and abdominal symptoms. He succumbed to death despite 22 days of intensive medical treatment. An autopsy revealed a ruptured gangrenous ileal volvulus with peritonitis and subdiaphragmatic abscess. Further laboratory analysis detected systemic Candida tropicalis and intestinal gramnegative bacterial sepsis, systemic Zika virus viremia, leptospirosis complicating rhabdomyolysis and disseminated intravascular coagulopathy, Type I Herpes Simplex virus infection of the tongue and upper gastrointestinal tract. The cause of death was the ruptured ileal volvulus, complicated with upper gastrointestinal bleeding due to Herpes simplex virus esophagitis in a malnourished patient with resolving leptospirosis and underlying Zika virus co-infection.
CONCLUSION: Rare clinical scenarios of adult-onset intestinal volvulus with concomitant multiple infections precludes clinical diagnosis and early treatment, leading to devastating consequences of clinical outcome. The positive clinical and postmortem correlation is a good learning lesson in many disciplines of medicine and science.
Fulltext Fault-Tolerant and Data-Intensive Resource Scheduling and Management for Scientific Applications in Cloud Computing

Ahmad Z, Jehangiri AI, Ala'anzy MA, Othman M, Umar AI

Sensors (Basel), 2021 Oct 30;21(21).
PMID: 34770545 DOI: 10.3390/s21217238

Cloud computing is a fully fledged, matured and flexible computing paradigm that provides services to scientific and business applications in a subscription-based environment. Scientific applications such as Montage and CyberShake are organized scientific workflows with data and compute-intensive tasks and also have some special characteristics. These characteristics include the tasks of scientific workflows that are executed in terms of integration, disintegration, pipeline, and parallelism, and thus require special attention to task management and data-oriented resource scheduling and management. The tasks executed during pipeline are considered as bottleneck executions, the failure of which result in the wholly futile execution, which requires a fault-tolerant-aware execution. The tasks executed during parallelism require similar instances of cloud resources, and thus, cluster-based execution may upgrade the system performance in terms of make-span and execution cost. Therefore, this research work presents a cluster-based, fault-tolerant and data-intensive (CFD) scheduling for scientific applications in cloud environments. The CFD strategy addresses the data intensiveness of tasks of scientific workflows with cluster-based, fault-tolerant mechanisms. The Montage scientific workflow is considered as a simulation and the results of the CFD strategy were compared with three well-known heuristic scheduling policies: (a) MCT, (b) Max-min, and (c) Min-min. The simulation results showed that the CFD strategy reduced the make-span by 14.28%, 20.37%, and 11.77%, respectively, as compared with the existing three policies. Similarly, the CFD reduces the execution cost by 1.27%, 5.3%, and 2.21%, respectively, as compared with the existing three policies. In case of the CFD strategy, the SLA is not violated with regard to time and cost constraints, whereas it is violated by the existing policies numerous times.
Comparative toxicity of eight metals on freshwater fish

Shuhaimi-Othman M, Yakub N, Ramle NA, Abas A

Toxicol Ind Health, 2015 Sep;31(9):773-82.
PMID: 23302712 DOI: 10.1177/0748233712472519

Two freshwater fish, Rasbora sumatrana (Cyprinidae) and Poecilia reticulata (guppy; Poeciliidae), were exposed to a range of eight heavy metals (copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn)) at varied concentrations for 96 h in the laboratory. Mortality was assessed and median lethal concentrations (LC50) were calculated. It was observed that the LC50 values increased with a decrease in mean exposure times, for all metals and for both fish types. The 96-h LC50 values for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.006, 0.10, 0.46, 0.63, 0.83, 1.71, 1.53, and 5.71 mg/L for R. sumatrana and 0.038, 0.17, 1.06, 1.99, 15.62, 1.46, 6.76, and 23.91 mg/L for P. reticulata, respectively. The metal toxicity trend for R. sumatrana and P. reticulata from most to least toxic was Cu > Cd > Zn > Pb > Ni > Al > Fe > Mn and Cu > Cd > Zn > Fe > Pb > Al > Ni > Mn, respectively. Results indicated that Cu was the most toxic metal on both fish, and R. sumatrana was more sensitive than P. reticulata to all the eight metals.
Measuring organic carbon, nutrients and heavy metals in rivers receiving leachate from controlled and uncontrolled municipal solid waste (MSW) landfills

Yusof N, Haraguchi A, Hassan MA, Othman MR, Wakisaka M, Shirai Y

Waste Manag, 2009 Oct;29(10):2666-80.
PMID: 19564103 DOI: 10.1016/j.wasman.2009.05.022

Since landfilling is the common method of waste disposal in Malaysia, river water is greatly exposed to the risk of contamination from leachate unless proper leachate management is carried out. In this study, leachates from three different types of landfills, namely active uncontrolled, active controlled and closed controlled, were characterized, and their relationships with river water chemistry were examined monthly for a year. The influence of leachate on river water chemistry from each type of landfill depended on many factors, including the presence of a leachate control mechanism, leachate characteristics, precipitation, surface runoff and the applied treatment. The impact of leachate from an active uncontrolled landfill was the highest, as the organic content, NH(4)(+)-N, Cd and Mn levels appeared high in the river. At the same time, influences of leachate were also observed from both types of controlled landfills in the form of inorganic nitrogen (NH(4)(+)-N, NO(3)(-)-N and NO(2)(-)-N) and heavy metals (Fe, Cr, Ni and Mn). Improper treatment practice led to high levels of some contaminants in the stream near the closed controlled landfill. Meanwhile, the active controlled landfill, which was located near the coastline, was exposed to the risk of contamination resulting from the pyrite oxidation of the surrounding area.
Fulltext Toxicity of Metals to a Freshwater Ostracod: Stenocypris major

Shuhaimi-Othman M, Yakub N, Ramle NA, Abas A

J Toxicol, 2011;2011:136104.
PMID: 21559091 DOI: 10.1155/2011/136104

Adults of freshwater ostracod Stenocypris major (Crustacea, Candonidae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed, and median lethal times (LT(50)) and concentrations (LC(50)) were calculated. LT(50) and LC(50) increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC(50)s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 25.2, 13.1, 1189.8, 526.2, 19743.7, 278.9, 3101.9, and 510.2 μg/L, respectively. Metals bioconcentration in S. major increases with exposure to increasing concentrations, and Cd was the most toxic to S. major, followed by Cu, Fe, Mn, Pb, Zn, Al, and Ni (Cd>Cu>Fe>Mn>Pb>Zn>Al>Ni). Comparison of LC(50) values for metals for this species with those for other freshwater crustacean reveals that S. major is equally or more sensitive to metals than most other tested crustacean.
Sensitivity of the freshwater prawn, Macrobrachium lanchesteri (Crustacea: Decapoda), to heavy metals

Shuhaimi-Othman M, Yakub N, Ramle NA, Abas A

Toxicol Ind Health, 2011 Jul;27(6):523-30.
PMID: 21343224 DOI: 10.1177/0748233710391993

Adult Macrobrachium lanchesteri were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn) and lead (Pb) concentrations. Mortality was assessed and median lethal times (LT₅₀) and concentrations (LC₅₀) were calculated. At the end of the 4-day period, live prawns were used to determine bioconcentration of the metals. LT₅₀ and LC₅₀ increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC₅₀s for 96 hours for Cu, Cd, Zn and Pb were 32.3, 7.0, 525.1 and 35.0 µg/L, respectively. Cu, Cd, Zn and Pb bioconcentration in M. lanchesteri increases with exposure to increasing concentrations and Cd was the most toxic to M. lanchesteri, followed by Pb, Cu and Zn. Comparison of LC₅₀ values for metals for this species with those for other freshwater crustacean organisms reveals that M. lanchesteri is equally or more sensitive to heavy metals than most other tested crustaceans.
Toxicity of eight metals to Malaysian freshwater midge larvae Chironomus javanus (Diptera, Chironomidae)

Shuhaimi-Othman M, Yakub N, Umirah NS, Abas A

Toxicol Ind Health, 2011 Nov;27(10):879-86.
PMID: 21402654 DOI: 10.1177/0748233711399318

Fourth instars larvae of freshwater midge Chironomus javanus (Diptera, Chironomidae) were exposed for a 4-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al) and manganese (Mn) concentrations. Mortality was assessed and median lethal concentrations (LC(50)) were calculated. LC(50) increased with the decrease in mean exposure times, for all metals. LC(50)s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al and Mn were 0.17, 0.06, 5.57, 0.72, 5.32, 0.62, 1.43 and 5.27 mg/L, respectively. Metals bioconcentration in C. javanus increases with exposure to increasing concentrations and Cd was the most toxic to C. javanus, followed by Cu, Fe, Pb, Al, Mn, Zn and Ni (Cd > Cu > Fe > Pb > Al > Mn > Zn > Ni). Comparison of LC(50) values for metals for this species with those for other freshwater midges reveals that C. javanus is equally or more sensitive to metals than most other tested dipteran.
Development of a questionnaire for assessing factors predicting blood donation among university students: a pilot study

Jalalian M, Latiff L, Hassan ST, Hanachi P, Othman M

Southeast Asian J Trop Med Public Health, 2010 May;41(3):660-6.
PMID: 20578556

University students are a target group for blood donor programs. To develop a blood donation culture among university students, it is important to identify factors used to predict their intent to donate blood. This study attempted to develop a valid and reliable measurement tool to be employed in assessing variables in a blood donation behavior model based on the Theory of Planned Behavior (TPB), a commonly used theoretical foundation for social psychology studies. We employed an elicitation study, in which we determined the commonly held behavioral and normative beliefs about blood donation. We used the results of the elicitation study and a standard format for creating questionnaire items for all constructs of the TPB model to prepare the first draft of the measurement tool. After piloting the questionnaire, we prepared the final draft of the questionnaire to be used in our main study. Examination of internal consistency using Chronbach's alpha coefficient and item-total statistics indicated the constructs "Intention" and "Self efficacy" had the highest reliability. Removing one item from each of the constructs, "Attitude," "Subjective norm," "Self efficacy," or "Behavioral beliefs", can considerably increase the reliability of the measurement tool, however, such action is controversial, especially for the variables "attitude" and "subjective norm." We consider all the items of our first draft questionnaire in our main study to make it a reliable measurement tool.
Synthesis and evaluation on pH- and temperature-responsive chitosan-p(MAA-co-NIPAM) hydrogels

Rasib SZM, Ahmad Z, Khan A, Akil HM, Othman MBH, Hamid ZAA, et al.

Int J Biol Macromol, 2018 Mar;108:367-375.
PMID: 29222015 DOI: 10.1016/j.ijbiomac.2017.12.021

In this study, chitosan-poly(methacrylic acid-co-N-isopropylacrylamide) [chitosan-p(MAA-co-NIPAM)] hydrogels were synthesized by emulsion polymerization. In order to be used as a carrier for drug delivery systems, the hydrogels had to be biocompatible, biodegradable and multi-responsive. The polymerization was performed by copolymerize MAA and NIPAM with chitosan polymer to produce a chitosan-based hydrogel. Due to instability during synthesis and complexity of components to produce the hydrogel, further study at different times of reaction is important to observe the synthesis process, the effect of end product on swelling behaviour and the most important is to find the best way to control the hydrogel synthesis in order to have an optimal swelling behaviour for drug release application. Studied by using Fourier transform infra-red (FTIR) spectroscopy found that, the synthesized was successfully produced stable chitosan-based hydrogel with PNIPAM continuously covered the outer surface of hydrogel which influenced much on the stability during synthesis. The chitosan and PMAA increased the zeta potential of the hydrogel and the chitosan capable to control shrinkage above human body temperature. The chitosan-p(MAA-co-NIPAM) hydrogels also responses to pH and temperature thus improved the ability to performance as a drug carrier.
Synthesis and functionalization of chitosan built hydrogel with induced hydrophilicity for extended release of sparingly soluble drugs

Ullah F, Javed F, Othman MBH, Khan A, Gul R, Ahmad Z, et al.

J Biomater Sci Polym Ed, 2018 03;29(4):376-396.
PMID: 29285989 DOI: 10.1080/09205063.2017.1421347

Addressing the functional biomaterials as next-generation therapeutics, chitosan and alginic acid were copolymerized in the form of chemically crosslinked interpenetrating networks (IPNs). The native hydrogel was functionalized via carbodiimide (EDC), catalyzed coupling of soft ligand (1,2-Ethylenediamine) and hard ligand (4-aminophenol) to replace -OH groups in alginic acid units for extended hydrogel- interfaces with the aqueous and sparingly soluble drug solutions. The chemical structure, Lower solution critical temperature (LCST ≈ 37.88 °C), particle size (Zh,app ≈ 150-200 nm), grain size (160-360 nm), surface roughness (85-250 nm), conductivity (37-74 mv) and zeta potential (16-32 mv) of native and functionalized hydrogel were investigated by using FT-IR, solid state-13C-NMR, TGA, DSC, FESEM, AFM and dynamic light scattering (DLS) measurements. The effective swelling, drug loading (47-78%) and drug release (53-86%) profiles were adjusted based on selective functionalization of hydrophobic IPNs due to electrostatic complexation and extended interactions of hydrophilic ligands with the aqueous and drug solutions. Drug release from the hydrogel matrices with diffusion coefficient n ≈ 0.7 was established by Non- Fickian diffusion mechanism. In vitro degradation trials of the hydrogel with a 20% loss of wet mass in simulated gastric fluid (SGF) and 38% loss of wet mass in simulated intestinal fluid (SIF), were investigated for 400 h through bulk erosion. Consequently, a slower rate of drug loading and release was observed for native hydrogel, due to stronger H-bonding, interlocking and entanglement within the IPNs, which was finely tuned and extended by the induced hydrophilic and functional ligands. In the light of induced hydrophilicity, such functional hydrogel could be highly attractive for extended release of sparingly soluble drugs.
Fulltext Growth Enhancement of Probiotic Pediococcus acidilactici by Extractive Fermentation of Lactic Acid Exploiting Anion-Exchange Resin

Othman M, Ariff AB, Kapri MR, Rios-Solis L, Halim M

Front Microbiol, 2018;9:2554.
PMID: 30420842 DOI: 10.3389/fmicb.2018.02554

Fermentation employing lactic acid bacteria (LAB) often suffers end-product inhibition which reduces the cell growth rate and the production of metabolite. The utility of adsorbent resins for in situ lactic acid removal to enhance the cultivation performance of probiotic, Pediococcus acidilactici was studied. Weak base anion-exchange resin, Amberlite IRA 67 gave the highest maximum uptake capacity of lactic acid based on Langmuir adsorption isotherm (0.996 g lactic acid/g wet resin) compared to the other tested anion-exchange resins (Amberlite IRA 410, Amberlite IRA 400, Duolite A7 and Bowex MSA). The application of Amberlite IRA 67 improved the growth of P. acidilactici about 67 times compared to the control fermentation without resin addition. Nevertheless, the in situ addition of dispersed resin in the culture created shear stress by resins collision and caused direct shear force to the cells. The growth of P. acidilactici in the integrated bioreactor-internal column system containing anion-exchange resin was further improved by 1.4 times over that obtained in the bioreactor containing dispersed resin. The improvement of the P. acidilactici growth indicated that extractive fermentation using solid phase is an effective approach for reducing by-product inhibition and increasing product titer.
Fulltext Sustainable and fast saliva-based COVID-19 virus diagnosis kit using a novel GO-decorated Au/FBG sensor

Samavati A, Samavati Z, Velashjerdi M, Fauzi Ismail A, Othman MHD, Eisaabadi B G, et al.

Chem Eng J, 2021 Sep 15;420:127655.
PMID: 33199974 DOI: 10.1016/j.cej.2020.127655

Monitoring the COVID-19 virus through patients' saliva is a favorable non-invasive specimen for diagnosis and infection control. In this study, salivary samples of COVID-19 patients collected from 6 patients with the median age of 58.5 years, ranging from 34 to 72 years (2 females and 4 males) were analyzed using an Au/fiber Bragg grating (FBG) probe decorated with GO. The probe measures the prevalence of positivity in saliva and the association between the virus density and changes to sensing elements. When the probe is immersed in patients' saliva, deviation of the detected light wavelength and intensity from healthy saliva indicate the presence of the virus and confirms infection. For a patient in the hyperinflammatory phase of desease, who has virus density of 1.2 × 108 copies/mL in saliva, the maximum wavelength shift and intensity changes after 1600 s were shown to be 1.12 nm and 2.01 dB, respectively. While for a patient in the early infection phase with 1.6 × 103 copies/mL, these values were 0.98 nm and 1.32 dB. The precise and highly sensitive FBG probe proposed in this study was found a reliable tool for quick detection of the COVID-19 virus within 10 s after exposure to patients' saliva in any stage of the disease.
Fulltext Low-cost commercial borosilicate glass slides for passive radiation dosimetry

Abdul Sani SF, Othman MHU, Alqahtani A, Almugren KS, Alkallas FH, Bradley DA

PLoS One, 2020;15(12):e0241550.
PMID: 33378398 DOI: 10.1371/journal.pone.0241550

For x- and gamma- irradiations delivering entrance doses from 2- up to 1000 Gy to commercial 1.0 mm thick borosilicate glass microscope slides, study has been made of their thermoluminescence yield. With an effective atomic number of 10.6 (approximating bone equivalence), photon energy dependency is apparent in the low x-ray energy range, with interplay between the photoelectric effect and attenuation. As an example, over the examined dose range, at 120 kVp the photon sensitivity has been found to be some 5× that of 60Co gamma irradiations, also with repeatability to within ~1%. The glow-curves, taking the form of a single prominent broad peak, have been deconvolved yielding at best fit a total of five peaks, the associated activation energies and frequency factors also being obtained. The results indicate borosilicate glass slides to offer promising performance as a low-cost passive radiation dosimeter, with utility for both radiotherapy and industrial applications.

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