Displaying publications 1 - 20 of 233 in total

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  1. Ayinla AY, Othman WAM, Rabiu M
    Acta Biotheor, 2021 Sep;69(3):225-255.
    PMID: 33877474 DOI: 10.1007/s10441-020-09406-8
    Tuberculosis has continued to retain its title as "the captain among these men of death". This is evident as it is the leading cause of death globally from a single infectious agent. TB as it is fondly called has become a major threat to the achievement of the sustainable development goals (SDG) and hence require inputs from different research disciplines. This work presents a mathematical model of tuberculosis. A compartmental model of seven classes was used in the model formulation comprising of the susceptible S, vaccinated V, exposed E, undiagnosed infectious I1, diagnosed infectious I2, treated T and recovered R. The stability analysis of the model was established as well as the condition for the model to undergo backward bifurcation. With the existence of backward bifurcation, keeping the basic reproduction number less than unity [Formula: see text] is no more sufficient to keep TB out of the community. Hence, it is shown by the analysis that vaccination program, diagnosis and treatment helps to control the TB dynamics. In furtherance to that, it is shown that preference should be given to diagnosis over treatment as diagnosis precedes treatment. It is as well shown that at lower vaccination rate (0-20%), TB would still be endemic in the population. As such, high vaccination rate is required to send TB out of the community.
    Matched MeSH terms: Basic Reproduction Number
  2. Ibrahim Ahmed Alhothily, Nazri Che Dom, Siti Aekbal Salleh, Anila Ali
    MyJurnal
    Introduction: Aedes albopictus is known for its aggressiveness towards human and recently expanded to more coun- tries outside the native regions. Thus, the demographic parameters of Aedes albopictus are important to determine the characteristics of this species mosquitoes in terms of the reproduction rates and dispersal distance. Materials and Methods: This study, was performed using a Shah Alam strain of Aedes albopictus originally collected in twenty district areas of the central zone of Shah Alam. This research applies field work-study with a cross-sectional design to investigate the demographic parameters of Aedes albopictus. The demographic evaluation of Aedes albopictus was conducted under the control environment in insectarium. Results: Investigation on the demographic parameters of Aedes albopictus clearly showed that there is a significance different observed in the total number of mosquito eggs produced in both high and low incidence rate IR areas (p=0.03). In contrast, other parameters showed insignificant value between high and low IR areas. Conclusion: The key to control the mosquito vectors population is by tracking the vector’s life cycle including its survival. Therefore, the outcome of this study may provide as a baseline to esti- mate the dengue outbreak in the current episystem.
    Matched MeSH terms: Reproduction
  3. Smith JD
    J Math Biol, 2004 Jan;48(1):105-18.
    PMID: 14685774
    A canonical/lognormal model for human demography is established, specifying the net maternity function and the age distribution for mothers of new-borns using a single macroscopic parameter vector of dimension five. The age distribution of mothers is canonical, while the net maternity function normalizes to a lognormal density. Comparison of an actual population with the model serves to identify anomalies in the population which may be indicative of phase transitions or influences from levels outside the demographic. Tracking the time development of the parameter vector may be used to predict the future state of a population, or to interpolate for data missing from the record. In accordance with classical theoretical considerations of Backman, Prigogine, et al., it emerges that the logarithm of a mother's age is the most fundamental time variable for demographic purposes.
    Matched MeSH terms: Reproduction
  4. Ng YF, Ain N, Lau KH
    Zootaxa, 2019 Nov 11;4695(4):zootaxa.4695.4.9.
    PMID: 31719347 DOI: 10.11646/zootaxa.4695.4.9
    Tenothrips keruing sp. n. is described from Malaysia. This new species was taken from the flowers of Dipterocarpus sublamellatus (local name Keruing kerut) during the recent mass-flowering. The male of this species has a pair of stout setae on abdominal tergite IX, and there are no sternal pore plates. A key to species of Tenothrips from Indomalaysia is provided.
    Matched MeSH terms: Reproduction
  5. Azra MN, Ikhwanuddin M
    Saudi J Biol Sci, 2016 Mar;23(2):257-67.
    PMID: 26981008 DOI: 10.1016/j.sjbs.2015.03.011
    Study of broodstock maturation diets is important in order to increase the quality of berried females, which indirectly improve the larval quantity in the hatchery production of cultured species. This paper reviewed the studies on the maturation diets for mud crab broodstock, genus Scylla and compared independently to identify their effect on reproductive performance and larval quality. The broodstock is usually caught from the wild and held in the spawning or maturation tank for further use of hatchery seed production. Mud crab broodstock was fed either natural diet, artificial diet or mixed diet. Trash fishes were commonly used as a natural feed for mud crab broodstock; meanwhile artificial diets are from formulated fish meal and various kinds of feed. The results indicated that mud crab broodstock has a high dietary requirement for lipids, fatty acids and protein which are to be used during the maturation and breeding processes. However, the natural diet produce better larval quality compared to the artificial diet. The mixed diet is the better diet which resulted in better reproductive performances such as growth, survival, fecundity and maturation processes. This review also discusses the problems in the previous studies for the potential future research to develop very high quality and cost-effective formulated diet for the enhancement of broodstock and seed production technology. Information from this review can be useful in developing a better quality of crustacean broodstock's diet for commercial hatchery production.
    Matched MeSH terms: Reproduction
  6. Chiang GL, Loong KP, Mahadevan S, Eng KL
    PMID: 2906483
    Five mark-release-recapture experiments with wild caught Ma. uniformis were conducted in an open swamp area at Batang Berjuntai in Selangor, 40 km from Kuala Lumpur, Malaysia, between May 1983 and January 1985. A total of 64 (0.14%) from the 45,950 females released were recaptured feeding on humans and cattle and resting in cattle-sheds. Substantially fewer (0.03% to 0.09%) females were recaptured from releases of blood-fed females than from releases of unfed females (0.20% to 0.23%). More than 70% of all recaptures were taken within a radius of 1.5 km around the point of release and the longest detected flight was 3.5 km. The mean dispersal distance for blood-fed and unfed females was 1.445 +/- 1.06 and 1.706 +/- 1.03 km, respectively. However, there was no significant difference in the overall mean dispersal of the two groups of females (p greater than 0.05). The duration of the gonotrophic cycle in the field was between 3 to 4 days. Daily survivorship estimates (0.783-0.867) based on the recapture rates of date specific marked females was comparable to that estimated vertically from the dissection of unmarked females (0.751-0.795). These experiments revealed the remarkable flying ability of Ma. uniformis and the importance of reinvasion must be recognized when control operations are restricted to small areas.
    Matched MeSH terms: Reproduction
  7. Arshat H, Tey NP, Ramli N
    Malays J Reprod Health, 1989 Jun;7(1):1-9.
    PMID: 12342395
    Matched MeSH terms: Reproduction
  8. Sukiran NL, Ma JC, Ma H, Su Z
    Plant Mol Biol, 2019 Jan;99(1-2):161-174.
    PMID: 30604322 DOI: 10.1007/s11103-018-0810-1
    KEY MESSAGE: Morphological and transcriptomic evidences provide us strong support for the function of ANAC019 in reproductive development under drought stress. Plants are sensitive to drought conditions, particularly at the reproductive stage. Several studies have reported drought effects on crop reproductive development, but the molecular mechanism underlying drought response during reproduction is still unclear. A recent study showed that drought induces in Arabidopsis inflorescence increased expression of many genes, including ANAC019. However, the function of ANAC019 in drought response during reproductive development has not been characterized. Here, we report an investigation of the ANAC019 function in the response to drought during reproduction. ANAC019 is preferentially expressed in the inflorescence compared with the leaf, suggesting possible roles in regulating both stress response and flower development. The anac019 mutant was more sensitive to drought than WT plant, and exhibited a delay in recovery of floral organ development under prolonged drought stress. Moreover, many fewer genes were differentially expressed in the anac019 inflorescence under drought than that of WT, suggesting that the mutant was impaired in drought-induced gene expression. The genes affected by ANAC019 were associated with stress and hormone responses as well as floral development. In particular, the expression levels of several key drought-induced genes, DREB2A, DREB2B, ARF2, MYB21 and MYB24, were dramatically reduced in the absence of ANAC019, suggesting that ANAC019 is an upstream regulator these genes for drought response and flower development. These results provide strong support for the potential function of ANAC019 in reproductive development under drought stress.
    Matched MeSH terms: Reproduction
  9. Kim JH, Ajani PA, Murray SA, Kang SM, Kim SH, Lim HC, et al.
    Harmful Algae, 2023 Mar;123:102392.
    PMID: 36894213 DOI: 10.1016/j.hal.2023.102392
    Pseudo-nitzschia pungens is a widely distributed marine pennate diatom. Hybrid zones, regions in which two different genotypes may interbreed, are important areas for speciation and ecology, and have been reported across the globe for this species. However, sexual reproduction between differing clades in the natural environment is yet to be observed and is difficult to predict. Here we carried out experiments using two mono-clonal cultures of P. pungens from different genotypes to measure the frequency and timing of sexual reproduction across varying biotic (growth phases and cell activity potential) and abiotic conditions (nutrients, light, turbulence). We found the mating rates and number of zygotes gradually decreased from exponential to late stationary growth phases. The maximum zygote abundance observed was 1,390 cells mL-1 and the maximum mating rate was 7.1%, both which occurred during the exponential growth phase. Conversely, only 9 cells mL-1 and a maximum mating rate of 0.1% was observed during the late stationary phase. We also found the higher the relative potential cell activity (rPCA) in parent cells, as determined by the concentration of chlorophyll a per cell and the ratio of colony formation during parent cultivations, revealed higher mating rates. Furthermore, sexual events were reduced under nutrient enrichment conditions, and mating pairs and zygotes were not formed under aphotic (dark) or shaking culture conditions (150 rpm). In order to understand the sexual reproduction of Pseudo-nitzschia in the natural environment, our results highlight that it is most likely the combination of both biotic (growth phase, Chl. a content) and abiotic factors (nutrients, light, turbulence) that will determine the successful union of intraspecific populations of P. pungens in any given region.
    Matched MeSH terms: Reproduction
  10. Barber CV, Yo JH, Rahman RA, Wallace EM, Palmer KR, Marshall SA
    Placenta, 2023 May;136:35-41.
    PMID: 37028223 DOI: 10.1016/j.placenta.2023.03.008
    Activin A is a two-subunit protein belonging to the transforming growth factor β superfamily. First discovered almost three decades ago, it has since been implicated in diverse physiological roles, ranging from wound repair to reproduction. After 30 years of research, altered activin A levels are now understood to be associated with the development of various diseases, making activin A a potential therapeutic target. In pregnancy, the placenta and fetal membranes are major producers of activin A, with significantly enhanced serum concentrations now recognised as a contributor to numerous gestational disorders. Evidence now suggests that circulating levels of activin A may be clinically relevant in the early detection of pregnancy complications, including miscarriage and preeclampsia. This review aims to summarise our current understanding of activin A as a potential diagnostic marker in common pregnancy pathologies.
    Matched MeSH terms: Reproduction/physiology
  11. Thomas FSK, Higuchi Y, Ogawa S, Soga T, Parhar IS
    Peptides, 2021 04;138:170504.
    PMID: 33539873 DOI: 10.1016/j.peptides.2021.170504
    Stress impairs the hypothalamic-pituitary-gonadal (HPG) axis, probably through its influence on the hypothalamic-pituitary-adrenal (= interrenals in the teleost, HPI) axis leading to reproductive failures. In this study, we investigated the response of hypothalamic neuropeptides, gonadotropin-inhibitory hormone (GnIH), a component of the HPG axis, and corticotropin-releasing hormone (CRH) a component of the HPI axis, to acute social defeat stress in the socially hierarchical male Nile tilapia (Oreochromis niloticus). Localization of GnIH cell bodies, GnIH neuronal processes, and numbers of GnIH cells in the brain during acute social defeat stress was studied using immunohistochemistry. Furthermore, mRNA levels of GnIH and CRH in the brain together with GnIH receptor, gpr147, and adrenocorticotropic hormone (ACTH) in the pituitary were quantified in control and socially defeated fish. Our results show, the number of GnIH-immunoreactive cell bodies and GnIH mRNA levels in the brain and the levels of gpr147 mRNA in the pituitary significantly increased in socially defeated fish. However, CRH and ACTH mRNA levels did not change during social defeat stress. Further, we found glucocorticoid type 2b receptor mRNA in laser captured immunostained GnIH cells. These results show that acute social defeat stress activates GnIH biosynthesis through glucocorticoid receptors type 2b signalling but does not change the CRH and ACTH mRNA expression in the tilapia, which could lead to temporary reproductive dysfunction.
    Matched MeSH terms: Reproduction/genetics; Reproduction/physiology
  12. Low BS, Das PK, Chan KL
    Phytother Res, 2014 Jul;28(7):1022-9.
    PMID: 24318772 DOI: 10.1002/ptr.5094
    The roots of Eurycoma longifolia Jack are popularly sought as herbal medicinal supplements to improve libido and general health amongst the local ethnic population. The major quassinoids of E. longifolia improved spermatogenesis and fertility but toxicity studies have not been well documented. The reproductive toxicity, two generation of foetus teratology and the up-and-down acute toxicity were investigated in Sprague-Dawley rats orally treated with quassinoid-rich E. longifolia extract (TAF273). The results showed that the median lethal dose (LD50 ) of TAF273 for female and male rats was 1293 and >2000 mg/kg, respectively. Fertility index and litter size of the TAF273 treated were significantly increased when compared with those of the non-treated animals. The TAF273-treated dams decreased in percentage of pre-implantation loss, post-implantation loss and late resorption. No toxic symptoms were observed on the TAF273-treated pregnant female rats and their foetuses were normal. The no-observed adverse effect level (NOAEL) obtained from reproductive toxicity and teratology studies of TAF273 in rats was 100 mg/kg body weight/day, being more than 10-fold lower than the LD50 value. Thus, any human dose derived from converting the rat doses of 100 mg/kg and below may be considered as safe for further clinical studies.
    Matched MeSH terms: Reproduction/drug effects
  13. Noor Laily Abu Bakar, Prasanta K Majumdar, Tan Boon Ann
    Malays J Reprod Health, 1983 Jan;1(1):1-10.
    PMID: 12279885
    Matched MeSH terms: Reproduction*
  14. Maimusa HA, Ahmad AH, Kassim NF, Rahim J
    J Am Mosq Control Assoc, 2016 Mar;32(1):1-11.
    PMID: 27105211 DOI: 10.2987/moco-32-01-1-11.1
    The life table developmental attributes of laboratory colonies of wild strains of Aedes albopictus and Aedes aegypti were analyzed and compared based on the age-stage, two-sex life table. Findings inclusive in this study are: adult preoviposition periods, total preoviposition period, mean intrinsic rate of increase (r), mean finite rate of increase (λ), net reproductive rates (R0), and mean generation time (T). The total preadult development time was 9.47 days for Ae. albopictus and 8.76 days for Ae. aegypti. The life expectancy was 19.01 days for Ae. albopictus and 19.94 days for Ae. aegypti. Mortality occurred mostly during the adult stage. The mean development time for each stage insignificantly correlated with temperature for Ae. albopictus (r  =  -0.208, P > 0.05) and (r  =  -0.312, P > 0.05) for Ae. aegypti. The population parameters suggest that Ae. albopictus and Ae. aegypti populations are r-strategists characterized by a high r, a large R0, and short T. This present study provides the first report to compare the life parameters of Ae. albopictus and Ae. aegypti strains from Penang island, Malaysia.
    Matched MeSH terms: Reproduction
  15. Rabaan AA, Al-Ahmed SH, Al-Malkey M, Alsubki R, Ezzikouri S, Al-Hababi FH, et al.
    Infez Med, 2021 03 01;29(1):10-19.
    PMID: 33664169
    Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a pandemic worldwide. On a daily basis the number of deaths associated with COVID-19 is rapidly increasing. The main transmission route of SARS-CoV-2 is through the air (airborne transmission). This review details the airborne transmission of SARS-CoV-2, the aerodynamics, and different modes of transmission (e.g. droplets, droplet nuclei, and aerosol particles). SARS-CoV-2 can be transmitted by an infected person during activities such as expiration, coughing, sneezing, and talking. During such activities and some medical procedures, aerosols and droplets contaminated with SARS-CoV-2 particles are formed. Depending on their sizes and the environmental conditions, such particles stay viable in the air for varying time periods and can cause infection in a susceptible host. Very few studies have been conducted to establish the mechanism or the aerodynamics of virus-loaded particles and droplets in causing infection. In this review we discuss the various forms in which SARS-CoV-2 virus particles can be transmitted in air and cause infections.
    Matched MeSH terms: Basic Reproduction Number/statistics & numerical data
  16. Baird AH, Guest JR, Edwards AJ, Bauman AG, Bouwmeester J, Mera H, et al.
    Sci Data, 2021 01 29;8(1):35.
    PMID: 33514754 DOI: 10.1038/s41597-020-00793-8
    The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology.
    Matched MeSH terms: Reproduction
  17. Raza A, Ahmadian A, Rafiq M, Salahshour S, Ferrara M
    Results Phys, 2021 Feb;21:103771.
    PMID: 33391985 DOI: 10.1016/j.rinp.2020.103771
    In the present study, a nonlinear delayed coronavirus pandemic model is investigated in the human population. For study, we find the equilibria of susceptible-exposed-infected-quarantine-recovered model with delay term. The stability of the model is investigated using well-posedness, Routh Hurwitz criterion, Volterra Lyapunov function, and Lasalle invariance principle. The effect of the reproduction number on dynamics of disease is analyzed. If the reproduction number is less than one then the disease has been controlled. On the other hand, if the reproduction number is greater than one then the disease has become endemic in the population. The effect of the quarantine component on the reproduction number is also investigated. In the delayed analysis of the model, we investigated that transmission dynamics of the disease is dependent on delay terms which is also reflected in basic reproduction number. At the end, to depict the strength of the theoretical analysis of the model, computer simulations are presented.
    Matched MeSH terms: Reproduction; Basic Reproduction Number
  18. Suhaimi AH, Kobayashi MJ, Satake A, Ng CC, Lee SL, Muhammad N, et al.
    PeerJ, 2023;11:e16368.
    PMID: 38047035 DOI: 10.7717/peerj.16368
    Climatic factors have commonly been attributed as the trigger of general flowering, a unique community-level mass flowering phenomenon involving most dipterocarp species that forms the foundation of Southeast Asian tropical rainforests. This intriguing flowering event is often succeeded by mast fruiting, which provides a temporary yet substantial burst of food resources for animals, particularly frugivores. However, the physiological mechanism that triggers general flowering, particularly in dipterocarp species, is not well understood largely due to its irregular and unpredictable occurrences in the tall and dense forests. To shed light on this mechanism, we employed ecological transcriptomic analyses on an RNA-seq dataset of a general flowering species, Shorea curtisii (Dipterocarpaceae), sequenced from leaves and buds collected at multiple vegetative and flowering phenological stages. We assembled 64,219 unigenes from the transcriptome of which 1,730 and 3,559 were differentially expressed in the leaf and the bud, respectively. Differentially expressed unigene clusters were found to be enriched with homologs of Arabidopsis thaliana genes associated with response to biotic and abiotic stresses, nutrient level, and hormonal treatments. When combined with rainfall data, our transcriptome data reveals that the trees were responding to a brief period of drought prior to the elevated expression of key floral promoters and followed by differential expression of unigenes that indicates physiological changes associated with the transition from vegetative to reproductive stages. Our study is timely for a representative general flowering dipterocarp species that occurs in forests that are under the constant threat of deforestation and climate change as it pinpoints important climate sensitive and flowering-related homologs and offers a glimpse into the cascade of gene expression before and after the onset of floral initiation.
    Matched MeSH terms: Reproduction/genetics
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