Displaying publications 1 - 20 of 31 in total

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  1. Hashim NA, Yusof ZYM, Saub R
    Community Dent Oral Epidemiol, 2019 02;47(1):24-31.
    PMID: 30187941 DOI: 10.1111/cdoe.12417
    OBJECTIVES: To evaluate the sensitivity and responsiveness of the Malay version of Early Childhood Oral Health Impact Scale (Malay-ECOHIS) to dental treatment of early childhood caries (ECC) under general anaesthesia (GA) and determine the minimally important difference (MID) for the Malay-ECOHIS.

    METHODS: A sample of 158 preschool children with ECC awaiting dental treatment under GA was recruited over an 8-month period. Parents self-completed the Malay-ECOHIS before and 4 weeks after their child's dental treatment. At 4 weeks follow-up, parents also responded to a global health transition judgement item. Data were analysed using independent and paired samples t tests, ANOVA and Pearson correlation coefficients.

    RESULTS: The response rate was 87.3%. The final sample comprised 76 male (55.1%) and 62 female (44.9%) preschool children with mean age of 4.5 (SD = 1.0) years. Following treatment, there were significant reductions in mean scores for total Malay-ECOHIS, child impact section (CIS), family impact section (FIS) and all domains, respectively (P 

  2. Nikmat AW, Al-Mashoor SH, Hashim NA
    Int Psychogeriatr, 2015 May;27(5):815-24.
    PMID: 25497589 DOI: 10.1017/S1041610214002609
    The evaluation of quality of life (QoL) among older adults has become increasingly important, and living arrangements play a pivotal role in determining the QoL of people with cognitive impairment (PWCI). Although informal care (home-based) is favored, transition to formal care (residential care) often becomes necessary, especially in the later stages of cognitive impairment. The primary objective was to compare the QoL of PWCI in the community and nursing homes. Additionally, factors differentiate the QoL of PWCI in these two settings were identified.
  3. Esa R, Hashim NA, Ayob Y, Yusof ZY
    BMC Oral Health, 2015 Mar 10;15:28.
    PMID: 25886943 DOI: 10.1186/s12903-015-0013-y
    BACKGROUND: To evaluate the psychometric properties of the faces version of the Modified Child Dental Anxiety Scale (MCDASf) Malay version in 5-6 and 9-12 year-old children.
    METHODS: The MCDASf was cross culturally adapted from English into Malay. The Malay version was tested for reliability and validity in 3 studies. In the Study 1, to determine test-retest reliability of MCDASf scale, 166 preschool children aged 5-6 years were asked to rank orders five cartoons faces depicting emotions from 'very happy' to 'very sad' faces on two separate occasions 3 weeks apart. A total of 87 other 5-6 year-old children completed the Malay-MCDASf on two separate occasions 3 weeks apart to determine test-retest reliability for Study 2. In study 3, 239 schoolchildren aged 9-12 years completed the Malay-MCDASf and the Malay-Dental Subscale of the Children Fear Survey Schedule (CFSS-DS) at the same sitting to determine the criterion and construct validity.
    RESULTS: In study 1, Kendall W test showed a high degree of concordance in ranking the cartoon faces picture cards on each of the 2 occasions (time 1, W = 0.955 and time 2, W = 0.954). The Malay-MCDASf demonstrated moderate test-retest reliability (Intraclass correlation coefficient = 0.63, p <0.001) and acceptable internal consistency for all the 6 items (Cronbach's alpha = 0.77) and 8 items (Cronbach's alpha = 0.73). The highest MCDASf scores were observed for the items 'injection in the gum' and 'tooth taken out' for both age groups. The MCDASf significantly correlated with the CFSS-DS (Pearson r = 0.67, p < 0.001).
    CONCLUSIONS: These psychometric findings support for the inclusion of a cartoon faces rating scale to assess child dental anxiety and the Malay-MCDASf is a reliable and valid measure of dental anxiety in 5-12 year-old children.
  4. Hashim NA, Ariaratnam S, Salleh MR, Said MA, Sulaiman AH
    East Asian Arch Psychiatry, 2016 Jun;26(2):77-82.
    PMID: 27377489
    OBJECTIVES: To determine the prevalence of major depressive disorder and its association with socio-demographic and clinical factors in patients with type 2 diabetes mellitus.

    METHODS: This was a cross-sectional study of patients with type 2 diabetes mellitus who attended the hospital-based primary care clinics at the University Malaya Medical Centre, Kuala Lumpur, Malaysia. The patients were interviewed using the Mini-International Neuropsychiatric Interview to diagnose depression based on the DSM-IV criteria. The socio-demographic and clinical data were obtained by interviewing the patients and subsequently verified against their respective case notes.

    RESULTS: A total of 204 patients were recruited. The prevalence of major depressive disorder was 15.7%. Major depressive disorder was significantly associated with younger age of patients (mean ± standard deviation, 57.8 ± 15.1 years, p = 0.04), younger age at diagnosis of diabetes mellitus (46.2 ± 13.0 years, p = 0.01), having secondary education (p = 0.02), and having a history of depression (p = 0.002). Multivariate analysis showed that current age (p = 0.04), duration of diabetes mellitus (p = 0.04), age at diagnosis of diabetes mellitus (p = 0.01), and secondary education (p = 0.01) were significant factors.

    CONCLUSIONS: The prevalence of major depressive disorder was high among patients with type 2 diabetes mellitus. Screening of patients with type 2 diabetes mellitus for depression should be performed periodically or routinely, especially in the primary care setting.
  5. Hashim NA, Abd Razak NA, Abu Osman NA, Gholizadeh H
    Proc Inst Mech Eng H, 2018 Jan;232(1):3-11.
    PMID: 29199518 DOI: 10.1177/0954411917744585
    Body-powered prostheses are known for their advantages of cost, reliability, training period, maintenance, and proprioceptive feedback. This study primarily aims to analyze the work related to the improvement of upper limb body-powered prostheses prior to 2016. A systematic review conducted via the search of the Web of Science electronic database, Google Scholar, and Google Patents identified 155 papers from 1921 to 2016. Sackett's initial rules of evidence were used to determine the levels of evidence, and only papers categorized in the design and development category and patents were analyzed. A total of 40 papers in the sixth level of "Design and Development" of an upper limb body-powered prosthesis were found. Approximately 81% were categorized under mechanical alteration. Most papers were patent-type documents (48%), with the Journal of Rehabilitation Research and Development publishing most of the articles related to the design and development of body-powered prostheses. Papers in the scope of the study were published once every 3 years in almost a century, proving that only a few studies were conducted to improve body-powered arms compared with myoelectric technology. Further research should be carried out mainly in areas that have received less attention.
  6. Hashim NA, Abd Razak NA, Gholizadeh H, Abu Osman NA
    JMIR Serious Games, 2021 Feb 04;9(1):e17017.
    PMID: 33538698 DOI: 10.2196/17017
    BACKGROUND: Brain plasticity is an important factor in prosthesis usage. This plasticity helps with brain adaptation to learn new movement and coordination patterns needed to control a prosthetic hand. It can be achieved through repetitive muscle training that is usually very exhausting and often results in considerable reduction in patient motivation. Previous studies have shown that a playful concept in rehabilitation can increase patient engagement and perseverance.

    OBJECTIVE: This study investigated whether the inclusion of video games in the upper limb amputee rehabilitation protocol could have a beneficial impact for muscle preparation, coordination, and patient motivation among individuals who have undergone transradial upper limb amputation.

    METHODS: Ten participants, including five amputee participants and five able-bodied participants, were enrolled in 10 1-hour sessions within a 4-week rehabilitation program. In order to investigate the effects of the rehabilitation protocol used in this study, virtual reality box and block tests and electromyography (EMG) assessments were performed. Maximum voluntary contraction was measured before, immediately after, and 2 days after interacting with four different EMG-controlled video games. Participant motivation was assessed with the Intrinsic Motivation Inventory (IMI) questionnaire and user evaluation survey.

    RESULTS: Survey analysis showed that muscle strength and coordination increased at the end of training for all the participants. The results of Pearson correlation analysis indicated that there was a significant positive association between the training period and the box and block test score (r8=0.95, P

  7. Nikmat AW, Azhar ZI, Shuib N, Hashim NA
    Malays J Med Sci, 2021 Jun;28(3):97-104.
    PMID: 34285648 DOI: 10.21315/mjms2021.28.3.9
    Background: Geriatric Depression Scale (GDS) has been widely used in assessing depression in elderly population. Using the Ministry of Health Malaysia definition for elderly, this study aimed to examine the construct validity and reliability of the GDS (Malay version) in elderly with cognitive impairment in Malaysia.

    Methods: A cross-sectional validation study involving 219 elderlies with cognitive impairment was conducted using universal sampling method. Participants aged 60 years old and above, scored less than 11 for the short mini mental state examination (SMMSE), have sufficient command of the Malay or English language, residing in the government nursing homes and attending memory clinics in government hospitals in Klang Valley were sampled. The GDS-15 English version underwent adaptation, translation, face validation and field testing to produce the Malay version. Psychometric analysis was performed using the exploratory factor analysis and its internal consistency was examined.

    Results: Mean age of participants were 72.61 ± 7.79. Majority were male (50.7%), Malay (50.2%), studied at least until primary school (71.7%) and stayed at nursing homes (50.2%). Construct validity showed significant Bartlett's test of sphericity (Chi-square = 1,340.058, P < 0.001) and Kaiser-Meyer-Olkin (KMO) test of 0.90. Factor loadings for each item in the depression domain were satisfactory ranging from 0.42 to 0.83. Factor loadings for each item in the psychosocial activities' domain were satisfactory ranging from 0.53 to 0.76. For the questionnaire reliability analysis, the total Cronbach's alpha for the final model was satisfactory, with and overall Cronbach's alpha of 0.89. Cronbach's alpha value for the depression and psychosocial activities domain was 0.861 and 0.80, respectively.

    Conclusion: The GDS (Malay version) is a valid and reliable tool to screen for depression in elderly with cognitive impairment.

  8. Kakihana Y, Hashim NA, Mizuno T, Anno M, Higa M
    Membranes (Basel), 2021 Jun 19;11(6).
    PMID: 34205395 DOI: 10.3390/membranes11060452
    Membrane resistance and permselectivity for counter-ions have important roles in determining the performance of cation-exchange membranes (CEMs). In this study, PVA-based polyanions-poly(vinyl alcohol-b-sodium styrene sulfonate)-were synthesized, changing the molar percentages CCEG of the cation-exchange groups with respect to the vinyl alcohol groups. From the block copolymer, poly(vinyl alcohol) (PVA)-based CEMs, hereafter called "B-CEMs", were prepared by crosslinking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations CGA. The ionic transport properties of the B-CEMs were compared with those previously reported for the CEMs prepared using a random copolymer-poly(vinyl alcohol-co-2-acrylamido-2-methylpropane sulfonic acid)-hereafter called "R-CEMs". The B-CEMs had lower water content than the R-CEMs at equal molar percentages of the cation-exchange groups. The charge density of the B-CEMs increased as CCEG increased, and reached a maximum value, which increased with increasing CGA. A maximum charge density of 1.47 mol/dm3 was obtained for a B-CEM with CCEG = 2.9 mol% and CGA = 0.10 vol.%, indicating that the B-CEM had almost two-thirds of the permselectivity of a commercial CEM (CMX: ASTOM Corp. Japan). The dynamic transport number and membrane resistance of a B-CEM with CCEG = 8.3 mol% and CGA = 0.10 vol.% were 0.99 and 1.6 Ωcm2, respectively. The B-CEM showed higher dynamic transport numbers than those of the R-CEMs with similar membrane resistances.
  9. Salleh WM, Hashim NA, Ahmad F, Heng Yen K
    Adv Pharm Bull, 2014 Dec;4(Suppl 2):527-31.
    PMID: 25671185 DOI: 10.5681/apb.2014.078
    The aim of this study was to investigate acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and antityrosinase activities of extracts from ten Piper species namely; P. caninum, P. lanatum, P. abbreviatum, P. aborescens, P. porphyrophyllum, P. erecticaule, P. ribesioides, P. miniatum, P. stylosum, and P. majusculum.
  10. Hashim NA, Ahmad AH, Rawi CS, Tahir NA, Basari N
    PMID: 18567442
    Life tables were constructed for twelve cohorts of immature stages of the dengue vector Ae. albopictus in a wooded area of Penang, Malaysia. The development time of Ae. albopictus ranged from 6 to 10 days depending on the mean environmental temperature (r = - 0.639, p < 0.05). Total cohort mortality was correlated with total development time (r = 0.713, p < 0.05) but not temperature (r = -0.477, p > 0.05). Rainfall was correlated with neither development time (r = 0.554, p > 0.05) nor mortality (r = 0.322, p > 0.05). There was a significant difference among the total mortality that occurred in the twelve cohorts (H = 119.783, df = 11, p < 0.05). There was also a significant difference in mortality among the different stages (H = 274.00, df = 4, p < 0.05).
  11. Teng CL, Nurjahan MI, Hashim NA, Punithambigai P, Leong KC, Mihat O
    Med J Malaysia, 2003 Jun;58(2):159-66.
    PMID: 14569735 MyJurnal
    Over a 2-week period, the management of upper respiratory tract infection by 24 medical officers and medical assistants in Seremban District was studied. Each practitioner recorded clinical data and prescription for twenty consecutive patients using a structured questionnaire. The extent to which the practitioners used "predictive features" (fever, absence of cough, cervical adenopathy, enlarged tonsils and exudates on tonsils) in clinical decision-making was analysed. The mean antibiotic prescription rate was 28.7% (95% CI: 24.6%, 33.0%). The antibiotic prescription rate of medical officers and medical assistants were similar. Five features were independently associated with antibiotic prescription (phlegm, fever, cervical adenopathy, red throat and tonsillar exudates). Antibiotics were prescribed for 22.1% of patients with 0-1 predictive features. High prescribers were 5 times more likely to prescribe antibiotics in this group of patients than low prescribers. To a large extent the clinical decision-making of practitioners in this study was evidence based. However, they were unduly influenced by purulent manifestation (phlegm) and redness of throat. The antibiotic prescription rate in these government health clinics is potentially reducible by means of educational intervention.
  12. Mohtor NH, Othman MHD, Ismail AF, Rahman MA, Jaafar J, Hashim NA
    Environ Sci Pollut Res Int, 2017 Jul;24(19):15905-15917.
    PMID: 28620856 DOI: 10.1007/s11356-017-9341-6
    Despite its extraordinary price, ceramic membrane can still be able to surpass polymeric membrane in the applications that require high temperature and pressure conditions, as well as harsh chemical environment. In order to alleviate the high cost of ceramic material that still becomes one of the major factors that contributes to the high production cost of ceramic membrane, various attempts have been made to use low cost ceramic materials as alternatives to well-known expensive ceramic materials such as alumina, silica, and zirconia in the fabrication of ceramic membrane. Thus, local Malaysian kaolin has been chosen as the ceramic material in this study for the preparation of kaolin hollow fibre membrane since it is inexpensive and naturally abundant in Malaysia. Due to the fact that the sintering process plays a prominent role in obtaining the desired morphology, properties, and performances of prepared ceramic membrane, the aim of this work was to study the effect of different sintering temperatures applied (ranging from 1200 to 1500 °C) in the preparation of kaolin hollow fibre membrane via dry/wet phase inversion-based spinning technique and sintering process. The morphology and properties of membrane were then characterised by SEM, AFM, FTIR, XRD, and three-point bending test, while the performances of membrane were investigated by conducting water permeation and Reactive Black 5 (RB5) dye rejection tests. From the experimental results obtained, the sintering temperature of 1400 °C could be selected as the optimum sintering temperature in preparing the kaolin hollow fibre membrane with the dense sponge-like structure of separation layer that resulted in the good mechanical strength of 70 MPa with the appreciable water permeation of 75 L/h m(2) bar and RB5 rejection of 68%.
  13. Hashim NA, Ahmad AH, Talib A, Athaillah F, Krishnan KT
    Trop Life Sci Res, 2018 Mar;29(1):213-227.
    PMID: 29644025 MyJurnal DOI: 10.21315/tlsr2018.29.1.14
    The occurrence of major outbreaks of dengue, and other vector borne diseases such as chikungunya and zika in tropical and subtropical regions has rendered control of the diseases a top-priority for many affected countries including Malaysia. Control of the mosquito vectors Aedes aegypti and Aedes albopictus through the reduction of breeding sites and the application of insecticides to kill immature forms and adults are the main control efforts to combat these diseases. The present study describes the association between Ae. albopictus and Ae. aegypti in shared breeding sites. This study is important given that any measure taken against one species may affect the other. A yearlong larval survey was conducted in four dengue endemic areas of Penang Island. Sorenson's coefficient index indicated that no association between number of the immatures of the two species regardless of container size and study location. Therefore, the mean number Ae. albopictus immature was not decreased in the presence of Ae. aegypti in shared breeding container. However Ae. aegypti appeared to prefer breeding in habitats not occupied by Ae. albopictus, the two species sharing breeding sites only where available containers were limited. In control efforts, eliminating the preferred breeding containers for one species might not affect or reduce the population of the other species.
  14. Mohamed Sofian Z, Harun N, Mahat MM, Nor Hashim NA, Jones SA
    Eur J Pharm Biopharm, 2021 Nov;168:53-61.
    PMID: 34455038 DOI: 10.1016/j.ejpb.2021.08.003
    Transiently associating amines with therapeutic agents through the formation of ion-pairs has been established both in vitro and in vivo as an effective means to systemically direct drug delivery to the lung via the polyamine transport system (PTS). However, there remains a need to better understand the structural traits required for effective PTS uptake of drug ion-pairs. This study aimed to use a structurally related series of amine counterions to investigate how they influenced the stability of theophylline ion-pairs and their active uptake in A549 cells. Using ethylamine (mono-amine), ethylenediamine (di-amine), spermidine (tri-amine) and spermine (tetra-amine) as counterions the ion-pair affinity was shown to increase as the number of protonated amine groups in the counterion structure increased. The mono and diamines generated a single hydrogen bond and the weakest ion-pair affinities (pKFTIR: 1.32 ± 0.04 and 1.43 ± 0.02) whereas the polyamines produced two hydrogen bonds and thus the strongest ion-pair affinities (pKFTIR: 1.93 ± 0.05 and 1.96 ± 0.04). In A549 cells depleted of endogenous polyamines using α-difluoromethylornithine (DFMO), the spermine-theophylline uptake was significantly increased (p 
  15. Hashim NA, Abd Razak NA, Shanmuganathan T, Mohd Jaladin RA, Gholizadeh H, Abu Osman NA
    PMID: 35044131 DOI: 10.23736/S1973-9087.22.06794-6
    INTRODUCTION: Virtual Reality has recently become a popular application for rehabilitation and motor control research. This technology has emerged as a valid addition to conventional therapy and promises a successful rehabilitation. This study describes recent research related to the use of virtual reality applications in the rehabilitation of individuals with upper limb loss and to see whether this technology has enough proof of its applicability.

    EVIDENCE ACQUISITION: Searches were conducted with the Web of Science, Google Scholar, IEEE Xplore, and PubMed databases from inception up to September 2020. Articles that employed virtual reality in the rehabilitation of individual with upper limb loss were included in the research if it is written in English, the keyword exists in the title and abstract; it uses visual feedback in non-immersive, semiimmersive, or fully immersive virtual environments. Data extraction was carried out by two independent researchers. The study was drafted using the Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols (PRISMA).

    EVIDENCE SYNTHESIS: A total of 38 articles met the inclusion criteria. Most studies were published between 2010 and 2020. 39% of the studies (n=15), originates from North America; 55% of the studies (n=21), were publicly funded; 61% of the studies (n=24), was without disclosure of conflict of interest; 82% of the studies (n=31), were cited in other studies. All the studies were published in journals and conference proceedings. 66% of the studies (n=25), has come out with positive outcome. The design studies were mostly case reports, case series, and poorly designed cohort studies that made up 55% (n=21) of all the studies cited here.

    CONCLUSIONS: The research conducted on the use of virtual reality in individual with upper limb loss rehabilitation is of very low quality. The improvements to the research protocol are much needed. It is not necessary to develop new devices, but rather to assess existing devices with well-conducted randomized controlled trials.

  16. Munretnam K, Alex L, Ramzi NH, Chahil JK, Kavitha IS, Hashim NA, et al.
    Mol Biol Rep, 2014;41(4):2501-8.
    PMID: 24443231 DOI: 10.1007/s11033-014-3107-8
    There is growing global interest to stratify men into different levels of risk to developing prostate cancer, thus it is important to identify common genetic variants that confer the risk. Although many studies have identified more than a dozen common genetic variants which are highly associated with prostate cancer, none have been done in Malaysian population. To determine the association of such variants in Malaysian men with prostate cancer, we evaluated a panel of 768 SNPs found previously associated with various cancers which also included the prostate specific SNPs in a population based case control study (51 case subjects with prostate cancer and 51 control subjects) in Malaysian men of Malay, Chinese and Indian ethnicity. We identified 21 SNPs significantly associated with prostate cancer. Among these, 12 SNPs were strongly associated with increased risk of prostate cancer while remaining nine SNPs were associated with reduced risk. However, data analysis based on ethnic stratification led to only five SNPs in Malays and 3 SNPs in Chinese which remained significant. This could be due to small sample size in each ethnic group. Significant non-genetic risk factors were also identified for their association with prostate cancer. Our study is the first to investigate the involvement of multiple variants towards susceptibility for PC in Malaysian men using genotyping approach. Identified SNPs and non-genetic risk factors have a significant association with prostate cancer.
  17. Nor Hashim NA, Ramzi NH, Velapasamy S, Alex L, Chahil JK, Lye SH, et al.
    Asian Pac J Cancer Prev, 2012;13(12):6005-10.
    PMID: 23464394
    BACKGROUND: Nasopharyngeal carcinoma (NPC) is endemic in Southern Chinese and Southeast Asian populations. Geographical and ethnic clustering of the cancer is due to genetic, environmental, and lifestyle risk factors. This case-control study aimed to identify or confirm both genetic and non-genetic risk factors for NPC in one of the endemic countries, Malaysia.

    MATERIALS AND METHOD: A panel of 768 single-nucleotide polymorphisms (SNPs) previously associated with various cancers and known non-genetic risk factors for NPC were selected and analyzed for their associations with NPC in a case-control study.

    RESULTS: Statistical analysis identified 40 SNPs associated with NPC risk in our population, including 5 documented previously by genome-wide association studies (GWAS) and other case-control studies; the associations of the remaining 35 SNPs with NPC were novel. In addition, consistent with previous studies, exposure to occupational hazards, overconsumption of salt-cured foods, red meat, as well as low intake of fruits and vegetables were also associated with NPC risk.

    CONCLUSIONS: In short, this study confirmed and/or identified genetic, environmental and dietary risk factors associated with NPC susceptibility in a Southeast Asian population.

  18. Chahil JK, Munretnam K, Samsudin N, Lye SH, Hashim NA, Ramzi NH, et al.
    Indian J Clin Biochem, 2015 Apr;30(2):134-9.
    PMID: 25883419 DOI: 10.1007/s12291-013-0414-0
    Genome-wide association studies have discovered multiple single nucleotide polymorphisms (SNPs) associated with the risk of common diseases. The objective of this study was to demonstrate the replication of previously published SNPs that showed statistical significance for breast cancer in the Malaysian population. In this case-control study, 80 subjects for each group were recruited from various hospitals in Malaysia. A total of 768 SNPs were genotyped and analyzed to distinguish risk and protective alleles. A total of three SNPs were found to be associated with increased risk of breast cancer while six SNPs showed protective effect. All nine were statistically significant SNPs (p ≤ 0.01), five SNPs from previous studies were successfully replicated in our study. Significant modifiable (diet) and non-modifiable (family history of breast cancer in first degree relative) risk factors were also observed. We identified nine SNPs from this study to be either conferring susceptibility or protection to breast cancer which may serve as potential markers in risk prediction.
  19. Hasan SW, Said SM, Sabri MF, Bakar AS, Hashim NA, Hasnan MM, et al.
    Sci Rep, 2016 07 06;6:29328.
    PMID: 27381946 DOI: 10.1038/srep29328
    Thermo-Electrochemical cells (Thermocells/TECs) transform thermal energy into electricity by means of electrochemical potential disequilibrium between electrodes induced by a temperature gradient (ΔT). Heat conduction across the terminals of the cell is one of the primary reasons for device inefficiency. Herein, we embed Poly(Vinylidene Fluoride) (PVDF) membrane in thermocells to mitigate the heat transfer effects - we refer to these membrane-thermocells as MTECs. At a ΔT of 12 K, an improvement in the open circuit voltage (Voc) of the TEC from 1.3 mV to 2.8 mV is obtained by employment of the membrane. The PVDF membrane is employed at three different locations between the electrodes i.e. x = 2 mm, 5 mm, and 8 mm where 'x' defines the distance between the cathode and PVDF membrane. We found that the membrane position at x = 5 mm achieves the closest internal ∆T (i.e. 8.8 K) to the externally applied ΔT of 10 K and corresponding power density is 254 nWcm(-2); 78% higher than the conventional TEC. Finally, a thermal resistivity model based on infrared thermography explains mass and heat transfer within the thermocells.
  20. Dieng H, The CC, Satho T, Miake F, Wydiamala E, Kassim NFA, et al.
    Acta Trop, 2019 Jun;194:93-99.
    PMID: 30922800 DOI: 10.1016/j.actatropica.2019.03.027
    Sound and its reception are crucial for reproduction, survival, and population maintenance of many animals. In insects, low-frequency vibrations facilitate sexual interactions, whereas noise disrupts the perception of signals from conspecifics and hosts. Despite evidence that mosquitoes respond to sound frequencies beyond fundamental ranges, including songs, and that males and females need to struggle to harmonize their flight tones, the behavioral impacts of music as control targets remain unexplored. In this study, we examined the effects of electronic music (Scary Monsters and Nice Sprites by Skrillex) on foraging, host attack, and sexual activities of the dengue vector Aedes aegypti. Adults were presented with two sound environments (music-off or music-on). Discrepancies in visitation, blood feeding, and copulation patterns were compared between environments with and without music. Ae. aegypti females maintained in the music-off environment initiated host visits earlier than those in the music-on environment. They visited the host significantly less often in the music-on than the music-off condition. Females exposed to music attacked hosts much later than their non-exposed peers. The occurrence of blood feeding activity was lower when music was being played. Adults exposed to music copulated far less often than their counterparts kept in an environment where there was no music. In addition to providing insight into the auditory sensitivity of Ae. aegypti to sound, our results indicated the vulnerability of its key vectorial capacity traits to electronic music. The observation that such music can delay host attack, reduce blood feeding, and disrupt mating provides new avenues for the development of music-based personal protective and control measures against Aedes-borne diseases.
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