Displaying publications 1 - 20 of 134 in total

  1. Li J, Kendall G
    PLoS ONE, 2015;10(8):e0136032.
    PMID: 26288088 DOI: 10.1371/journal.pone.0136032
    In evolutionary game theory, evolutionarily stable states are characterised by the folk theorem because exact solutions to the replicator equation are difficult to obtain. It is generally assumed that the folk theorem, which is the fundamental theory for non-cooperative games, defines all Nash equilibria in infinitely repeated games. Here, we prove that Nash equilibria that are not characterised by the folk theorem do exist. By adopting specific reactive strategies, a group of players can be better off by coordinating their actions in repeated games. We call it a type-k equilibrium when a group of k players coordinate their actions and they have no incentive to deviate from their strategies simultaneously. The existence and stability of the type-k equilibrium in general games is discussed. This study shows that the sets of Nash equilibria and evolutionarily stable states have greater cardinality than classic game theory has predicted in many repeated games.
  2. Chen X, Li J, Xiao S, Liu X
    Gene, 2016 Jan 15;576(1 Pt 3):537-43.
    PMID: 26546834 DOI: 10.1016/j.gene.2015.11.001
    Paphia textile is an important, aquaculture bivalve clam species distributed mainly in China, Philippines, and Malaysia. Recent studies of P. textile have focused mainly on artificial breeding and nutrition analysis, and the transcriptome and genome of P. textile have rarely been reported. In this work, the transcriptome of P. textile foot tissue was sequenced on an Illumina HiSeq™ 2000 platform. A total of 20,219,795 reads were generated, resulting in 4.08 Gb of raw data. The raw reads were cleaned and assembled into 54,852 unigenes with an N50 length of 829 bp. Of these unigenes, 38.92% were successfully annotated based on their matches to sequences in seven public databases. Among the annotated unigenes, 14,571 were assigned Gene Ontology terms, 5448 were classified to Clusters of Orthologous Groups categories, and 6738 were mapped to 228 pathways in the Kyoto Encyclopedia of Genes and Genomes database. For functional marker development, 5605 candidate simple sequence repeats were identified in the transcriptome and 80 primer pairs were selected randomly and amplified in a wild population of P. textile. A total of 36 loci that exhibited obvious repeat length polymorphisms were detected. The transcriptomic data and microsatellite markers will provide valuable resources for future functional gene analyses, genetic map construction, and quantitative trait loci mapping in P. textile.
  3. Phillips T, Li J, Kendall G
    PLoS ONE, 2014;9(5):e95742.
    PMID: 24796325 DOI: 10.1371/journal.pone.0095742
    Human cooperation and altruism towards non-kin is a major evolutionary puzzle, as is 'strong reciprocity' where no present or future rewards accrue to the co-operator/altruist. Here, we test the hypothesis that the development of extra-somatic weapons could have influenced the evolution of human cooperative behaviour, thus providing a new explanation for these two puzzles. Widespread weapons use could have made disputes within hominin groups far more lethal and also equalized power between individuals. In such a cultural niche non-cooperators might well have become involved in such lethal disputes at a higher frequency than cooperators, thereby increasing the relative fitness of genes associated with cooperative behaviour. We employ two versions of the evolutionary Iterated Prisoner's Dilemma (IPD) model--one where weapons use is simulated and one where it is not. We then measured the performance of 25 IPD strategies to evaluate the effects of weapons use on them. We found that cooperative strategies performed significantly better, and non-cooperative strategies significantly worse, under simulated weapons use. Importantly, the performance of an 'Always Cooperate' IPD strategy, equivalent to that of 'strong reciprocity', improved significantly more than that of all other cooperative strategies. We conclude that the development of extra-somatic weapons throws new light on the evolution of human altruistic and cooperative behaviour, and particularly 'strong reciprocity'. The notion that distinctively human altruism and cooperation could have been an adaptive trait in a past environment that is no longer evident in the modern world provides a novel addition to theory that seeks to account for this major evolutionary puzzle.
  4. He C, Ding N, Li J, Li Y
    Wei Sheng Wu Xue Bao, 2002 Aug;42(4):436-41.
    PMID: 12557549
    A Chicken anemia virus has been isolated from a chicken flock in Harbin of China. The genome of the ivrus was cloned through polymerase chain reaction(PCR) and sequence of the genome was analyzed. The cycle genome is made of 2298 base pairs including three overlapping open reading frames(vp1, vp2, vp3) and a regulative region. Comparing sequence of the genome through BLAST in GenBank, this sequence exhibits 96.9% identity with other genome of CA Vs and least. Multiple alignment of this genome of this virus, 26p4, strain isolated in Germany, strain isolated in Malaysia and Cux-1 found that this sequence exhibits 98.2% (42/2298), 98.2% (42/2298), 96.9% (72/2298) and 97.5% (60/2319) identify with them, respectively. A new CAV strain was isolated and it has better identify with CAV isolated in Europe countries than is Asia country Malaysia. Multiple alignment of VP1, VP2, VP3 of 26p4, strain isolated in Germany, strain isolated in Malaysia, Cux-1 and strain isolated in Harbin of China found the VP2 the most conservative.
  5. Kissinger JC, Collins WE, Li J, McCutchan TF
    J. Parasitol., 1998 Apr;84(2):278-82.
    PMID: 9576499
    Plasmodium inui (Halberstaedter and von Prowazek, 1907), a malarial parasite of Old World monkeys that occurs in isolated pockets throughout the Celebes, Indonesia, Malaysia, and the Philippines, has traditionally been considered to be related more closely to Plasmodium malariae of humans (and its primate counterpart Plasmodium brasilianum), than to other primate Plasmodium species. This inference was made in part because of the similarities in the periodicities or duration of the asexual cycle in the blood, the extended sporogonic cycle, and the longer period of time for development of the pre-erythrocytic stages in the liver. Both P. inui and P. malariae have quartan (72 hr) periodicities associated with their asexual cycle, whereas other primate malarias, such as Plasmodium fragile and Plasmodium cynomolgi, are associated with tertian periodicities (48 hr), and Plasmodiumn knowlesi, with a quotidian (24 hr) periodicity. Phylogenetic analyses of portions of orthologous small subunit ribosomal genes reveal that P. inui is actually more closely related to the Plasmodium species of the "vivax-type" lineage than to P. malariae. Ribosomal sequence analysis of many different, geographically isolated, antigenically distinct P. inui isolates reveals that the isolates are nearly identical in sequence and thus members of the same species.
  6. Tackett S, Wright S, Lubin R, Li J, Pan H
    Med Educ, 2017 Mar;51(3):280-289.
    PMID: 27896846 DOI: 10.1111/medu.13120
    OBJECTIVE: To assess whether favourable perceptions of the learning environment (LE) were associated with better quality of life, less burnout and more empathy across three undergraduate medical education programmes in Israel, Malaysia and China.

    METHODS: Cross-sectional surveys were administered at the end of the 2013-2014 academic year at three medical schools: Technion American Medical Students Program (TAMS) in Israel, Perdana University-Royal College of Surgeons in Ireland School of Medicine (PURCSI) in Malaysia and Peking Union Medical College (PUMC) in China. LE perceptions were assessed using the Johns Hopkins Learning Environment Scale (JHLES). Well-being was assessed using validated items for quality of life and the depersonalisation and emotional exhaustion domains of burnout. The 20-item Jefferson Empathy Scale assessed empathy. Statistical analyses included bivariate regressions and multivariate regressions that adjusted for gender, school, class year and perceived academic rank.

    RESULTS: Overall, 400/622 (64.3%) students responded, with the following rates by site: TAMS 92/121 (76.0%), PURCSI 160/198 (80.1%) and PUMC 148/303 (48.8%). In multivariate models, favourable overall LE perceptions were associated with higher odds of good quality of life (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.8-5.8; p < 0.001) and lower odds of emotional exhaustion (OR, 0.34; 95% CI, 0.24-0.50; p < 0.001) and depersonaliation (OR, 0.30; 95% CI, 0.24-0.37; p = 0.001). 'Community of Peers', one of seven factors in the JHLES, was the only one to be independently associated with better quality of life and less emotional exhaustion and depersonalisation. After adjusting for covariates, there was not a statistically significant association between overall LE and empathy (OR, 1.4; 95% CI, 0.91-2.2; p = 0.12).

    CONCLUSIONS: Students' LE perceptions are closely associated with their well-being, and fostering peer community may hold promise for enhancing quality of life and protecting against burnout. Across these three settings, LE and empathy were not closely related, suggesting that any influence of learning environment on empathy would be modest.
  7. Gao X, Guo L, Li J, Thu HE, Hussain Z
    J Control Release, 2018 12 28;292:29-57.
    PMID: 30359665 DOI: 10.1016/j.jconrel.2018.10.024
    Lung cancer (LC) is the second most prevalent type of cancer and primary cause of mortality among both men and women, worldwide. The most commonly employed diagnostic modalities for LC include chest X-ray (CXR), magnetic-resonance-imaging (MRI), computed tomography (CT-scan), and fused-positron-emitting-tomography-CT (PET-CT). Owing to several limitations associated with the use of conventional diagnostic tools such as radiation burden to the patient, misleading diagnosis ("missed lung cancer"), false staging and low sensitivity and resolution, contemporary diagnostic regimen needed to be employed for screening of LC. In recent decades, nanotechnology-guided interventions have been transpired as emerging nanoimaging probes for detection of LC at advanced stages, while producing signal amplification, better resolution for surface and deep tissue imaging, and enhanced translocation and biodistribution of imaging probes within the cancerous tissues. Besides enormous potential of nanoimaging probes, nanotechnology-based advancements have also been evidenced for superior efficacy for treatment of LC and abolishing pulmonary metastasis (PM). The success of nanotherapeutics is due to their ability to maximise translocation and biodistribution of anti-neoplastic agents into the tumor tissues, improve pharmacokinetic profiles of anti-metastatic agents, optimise target-specific drug delivery, and control release kinetics of encapsulated moieties in target tissues. This review aims to overview and critically discuss the superiority of nanoimaging probes and nanotherapeutics over conventional regimen for early detection of LC and abolishing PM. Current challenges to clinical transition of nanoimaging probes and therapeutic viability of nanotherapeutics for treatment for LC and PM have also been pondered.
  8. Mahamad Maifiah MH, Velkov T, Creek DJ, Li J
    Methods Mol. Biol., 2019;1946:321-328.
    PMID: 30798566 DOI: 10.1007/978-1-4939-9118-1_28
    Acinetobacter baumannii is rapidly emerging as a multidrug-resistant pathogen responsible for nosocomial infections including pneumonia, bacteremia, wound infections, urinary tract infections, and meningitis. Metabolomics provides a powerful tool to gain a system-wide snapshot of cellular biochemical networks under defined conditions and has been increasingly applied to bacterial physiology and drug discovery. Here we describe an optimized sample preparation method for untargeted metabolomics studies in A. baumannii. Our method provides a significant recovery of intracellular metabolites to demonstrate substantial differences in global metabolic profiles among A. baumannii strains.
  9. Zelenev A, Li J, Mazhnaya A, Basu S, Altice FL
    Lancet Infect Dis, 2018 02;18(2):215-224.
    PMID: 29153265 DOI: 10.1016/S1473-3099(17)30676-X
    BACKGROUND: Chronic infections with hepatitis C virus (HCV) and HIV are highly prevalent in the USA and concentrated in people who inject drugs. Treatment as prevention with highly effective new direct-acting antivirals is a prospective HCV elimination strategy. We used network-based modelling to analyse the effect of this strategy in HCV-infected people who inject drugs in a US city.

    METHODS: Five graph models were fit using data from 1574 people who inject drugs in Hartford, CT, USA. We used a degree-corrected stochastic block model, based on goodness-of-fit, to model networks of injection drug users. We simulated transmission of HCV and HIV through this network with varying levels of HCV treatment coverage (0%, 3%, 6%, 12%, or 24%) and varying baseline HCV prevalence in people who inject drugs (30%, 60%, 75%, or 85%). We compared the effectiveness of seven treatment-as-prevention strategies on reducing HCV prevalence over 10 years and 20 years versus no treatment. The strategies consisted of treatment assigned to either a randomly chosen individual who injects drugs or to an individual with the highest number of injection partners. Additional strategies explored the effects of treating either none, half, or all of the injection partners of the selected individual, as well as a strategy based on respondent-driven recruitment into treatment.

    FINDINGS: Our model estimates show that at the highest baseline HCV prevalence in people who inject drugs (85%), expansion of treatment coverage does not substantially reduce HCV prevalence for any treatment-as-prevention strategy. However, when baseline HCV prevalence is 60% or lower, treating more than 120 (12%) individuals per 1000 people who inject drugs per year would probably eliminate HCV within 10 years. On average, assigning treatment randomly to individuals who inject drugs is better than targeting individuals with the most injection partners. Treatment-as-prevention strategies that treat additional network members are among the best performing strategies and can enhance less effective strategies that target the degree (ie, the highest number of injection partners) within the network.

    INTERPRETATION: Successful HCV treatment as prevention should incorporate the baseline HCV prevalence and will achieve the greatest benefit when coverage is sufficiently expanded.

    FUNDING: National Institute on Drug Abuse.

  10. Anandkumar A, Nagarajan R, Prabakaran K, Bing CH, Rajaram R, Li J, et al.
    Mar. Pollut. Bull., 2019 Aug;145:56-66.
    PMID: 31590824 DOI: 10.1016/j.marpolbul.2019.05.002
    The concentration of nine trace elements were analyzed in the different tissue organs of commonly available crabs (Portunus sanguinolentus, Portunus pelagicus and Scylla serrate) and bivalve (Polymesoda erosa) species collected from the Miri coast, Borneo in order to evaluate the potential health risk by consumption of these aquatic organisms. Among the analyzed organs, metal accumulation was higher in the gill tissues. The essential (Cu and Zn) and non-essential (Pb and Cd) elements showed the highest (i.e. Zn) and lowest concentrations (i.e. Cd) in their tissue organs, respectively. The estimated daily intake and hazard indices of all metals in the muscle indicate that the measured values were below the provisional tolerable daily intake suggested by the joint FAO/WHO Expert Committee on Food Additives. Compared to Malaysian and international seafood guideline values the results obtained from the present study are lower than the permissible limits and safe for consumption.
  11. Mariapun S, Ho WK, Kang PC, Li J, Lindström S, Yip CH, et al.
    Cancer Epidemiol. Biomarkers Prev., 2016 Feb;25(2):327-33.
    PMID: 26677210 DOI: 10.1158/1055-9965.EPI-15-0746
    Mammographic density is an established risk factor for breast cancer and has a strong heritable component. Genome-wide association studies (GWAS) for mammographic density conducted in women of European descent have identified several genetic associations, but none of the studies have been tested in Asians. We sought to investigate whether these genetic loci, and loci associated with breast cancer risk and breast size, are associated with mammographic density in an Asian cohort.
  12. Xu J, Jiang H, Li J, Cheng KK, Dong J, Chen Z
    PLoS ONE, 2015;10(4):e0119654.
    PMID: 25849323 DOI: 10.1371/journal.pone.0119654
    Wilson's disease (WD), also known as hepatoleticular degeneration (HLD), is a rare autosomal recessive genetic disorder of copper metabolism, which causes copper to accumulate in body tissues. In this study, rats fed with copper-laden diet are used to render the clinical manifestations of WD, and their copper toxicity-induced organ lesions are studied. To investigate metabolic behaviors of 'decoppering' process, penicillamine (PA) was used for treating copper-laden rats as this chelating agent could eliminate excess copper through the urine. To date, there has been limited metabolomics study on WD, while metabolic impacts of copper accumulation and PA administration have yet to be established.
  13. Li J, Shimizu K, Akasako H, Lu Z, Akiyama S, Goto M, et al.
    Bioresour. Technol., 2015 Jan;175:463-72.
    PMID: 25459856 DOI: 10.1016/j.biortech.2014.10.047
    This study revealed the biotic and abiotic parameters driving the variations in microcystins (MCs) biodegradability of a practical biological treatment facility (BTF). Results showed that similar trends of seasonal variation were seen for microcystin-LR (MCLR) biodegradability of biofilms on the BTF and indigenous MCLR-degrader population, where both peaks co-occurred in October, following the peaks of natural MCLR concentration and water temperature observed in August. The lag period might be required for accumulation of MCLR-degraders and MCLR-degrading enzyme activity. The MCLR-degrader population was correlated to temperature, MCLR and chlorophyll-a concentration in water where the biofilms submerged, indicating that these abiotic and biotic parameters exerted direct and/or indirect influences on seasonal variation in MCLR-biodegradability. In comparison, no effect of other co-existing MCs on biodegradation of one MC was observed. However, proliferation of MC-degraders along biodegradation processes positively responded to total amount of MCs, suggesting that multiple MCs contributed additively to MC-degrader proliferation.
  14. Teo BW, Bagchi S, Xu H, Toh QC, Li J, Lee EJ
    Singapore Med J, 2014 Dec;55(12):652-5.
    PMID: 25630320
    INTRODUCTION: Clinical practice guidelines recommend using creatinine-based equations to estimate glomerular filtration rates (GFRs). While these equations were formulated for Caucasian-American populations and have adjustment coefficients for African-American populations, they are not validated for other ethnicities. The Chronic Kidney Disease-Epidemiology Collaborative Group (CKD-EPI) recently developed a new equation that uses both creatinine and cystatin C. We aimed to assess the accuracy of this equation in estimating the GFRs of participants (healthy and with chronic kidney disease [CKD]) from a multiethnic Asian population.

    METHODS: Serum samples from the Asian Kidney Disease Study and the Singapore Kidney Function Study were used. GFR was measured using plasma clearance of 99mTc-DTPA. GFR was estimated using the CKD-EPI equations. The performance of GFR estimation equations were examined using median and interquartile range values, and the percentage difference from the measured GFR.

    RESULTS: The study comprised 335 participants (69.3% with CKD; 38.5% Chinese, 29.6% Malays, 23.6% Indians, 8.3% others), with a mean age of 53.5 ± 15.1 years. Mean standardised serum creatinine was 127 ± 86 μmol/L, while mean standardised serum cystatin C and mean measured GFR were 1.43 ± 0.74 mg/L and 67 ± 33 mL/min/1.73 m2, respectively. The creatinine-cystatin C CKD-EPI equation performed the best, with an estimated GFR of 67 ± 35 mL/min/1.73 m2.

    CONCLUSION: The new creatinine-cystatin C equation estimated GFR with little bias, and had increased precision and accuracy in our multiethnic Asian population. This two-biomarker equation may increase the accuracy of population studies on CKD, without the need to consider ethnicity.
  15. Hong W, Li J, Laughton CA, Yap LF, Paterson IC, Wang H
    J. Mol. Graph. Model., 2014 Jun;51:193-202.
    PMID: 24937176 DOI: 10.1016/j.jmgm.2014.05.010
    Protein arginine methyltransferases (PRMTs) catalyse the methylation of arginine residues of target proteins. PRMTs utilise S-adenosyl methionine (SAM) as the methyl group donor, leading to S-adenosyl homocysteine (SAH) and monomethylarginine (mMA). A combination of homology modelling, molecular docking, Active Site Pressurisation, molecular dynamic simulations and MM-PBSA free energy calculations is used to investigate the binding poses of three PRMT1 inhibitors (ligands 1-3), which target both SAM and substrate arginine binding sites by containing a guanidine group joined by short linkers with the SAM derivative. It was assumed initially that the adenine moieties of the inhibitors would bind in sub-site 1 (PHE44, GLU137, VAL136 and GLU108), the guanidine side chain would occupy sub-site 2 (GLU 161, TYR160, TYR156 and TRP302), with the amino acid side chain occupying sub-site 3 (GLU152, ARG62, GLY86 and ASP84; pose 1). However, the SAH homocysteine moiety does not fully occupy sub-site 3, suggesting another binding pose may exist (pose 2), whereby the adenine moiety binds in sub-site 1, the guanidine side chain occupies sub-site 3, and the amino acid side chain occupies sub-site 2. Our results indicate that ligand 1 (pose 1 or 2), ligand 2 (pose 2) and ligand 3 (pose 1) are the predominant binding poses and we demonstrate for the first time that sub-site 3 contains a large space that could be exploited in the future to develop novel inhibitors with higher binding affinities.
  16. Huang Y, Xu Y, Li J, Xu W, Zhang G, Cheng Z, et al.
    Environ. Sci. Technol., 2013;47(23):13395-403.
    PMID: 24251554 DOI: 10.1021/es403138p
    Nineteen pairs of gaseous and surface seawater samples were collected along the cruise from Malaysia to the south of Bay of Bengal passing by Sri Lanka between April 12 and May 4, 2011 on the Chinese research vessel Shiyan I to investigate the latest OCP pollution status over the equatorial Indian Ocean. Significant decrease of α-HCH and γ-HCH was found in the air and dissolved water phase owing to global restriction for decades. Substantially high levels of p,p'-DDT, o,p'-DDT, trans-chlordane (TC), and cis-chlordane (CC) were observed in the water samples collected near Sri Lanka, indicating fresh continental riverine input of these compounds. Fugacity fractions suggest equilibrium of α-HCH at most sampling sites, while net volatilization for DDT isomers, TC and CC in most cases. Enantiomer fractions (EFs) of α-HCH and o,p'-DDT in the air and water samples were determined to trace the source of these compounds in the air. Racemic or close to racemic composition was found for atmospheric α-HCH and o,p'-DDT, while significant depletion of (+) enantiomer was found in the water phase, especially for o,p'-DDT (EFs = 0.310 ± 0.178). 24% of α-HCH in the lower air over the open sea of the equatorial Indian Ocean is estimated to be volatilized from local seawater, indicating that long-range transport is the main source.
  17. Deris ZZ, Akter J, Sivanesan S, Roberts KD, Thompson PE, Nation RL, et al.
    J. Antibiot., 2014 Feb;67(2):147-51.
    PMID: 24169795 DOI: 10.1038/ja.2013.111
    Polymyxin B and colistin were examined for their ability to inhibit the type II NADH-quinone oxidoreductases (NDH-2) of three species of Gram-negative bacteria. Polymyxin B and colistin inhibited the NDH-2 activity in preparations from all of the isolates in a concentration-dependent manner. The mechanism of NDH-2 inhibition by polymyxin B was investigated in detail with Escherichia coli inner membrane preparations and conformed to a mixed inhibition model with respect to ubiquinone-1 and a non-competitive inhibition model with respect to NADH. These suggest that the inhibition of vital respiratory enzymes in the bacterial inner membrane represents one of the secondary modes of action for polymyxins.
  18. Yamayoshi S, Yamashita Y, Li J, Hanagata N, Minowa T, Takemura T, et al.
    Nat. Med., 2009 Jul;15(7):798-801.
    PMID: 19543282 DOI: 10.1038/nm.1992
    Enterovirus 71 (EV71) belongs to human enterovirus species A of the genus Enterovirus within the family Picornaviridae. EV71, together with coxsackievirus A16 (CVA16), are most frequently associated with hand, foot and mouth disease (HFMD). Although HFMD is considered a mild exanthematous infection, infections involving EV71, but not CVA16, can progress to severe neurological disease, including fatal encephalitis, aseptic meningitis and acute flaccid paralysis. In recent years, epidemic and sporadic outbreaks of neurovirulent EV71 infections have been reported in Taiwan, Malaysia, Singapore, Japan and China. Here, we show that human scavenger receptor class B, member 2 (SCARB2, also known as lysosomal integral membrane protein II or CD36b like-2) is a receptor for EV71. EV71 binds soluble SCARB2 or cells expressing SCARB2, and the binding is inhibited by an antibody to SCARB2. Expression of human SCARB2 enables normally unsusceptible cell lines to support EV71 propagation and develop cytopathic effects. EV71 infection is hampered by the antibody to SCARB2 and soluble SCARB2. SCARB2 also supports the infection of the milder pathogen CVA16. The identification of SCARB2 as an EV71 and CVA16 receptor contributes to a better understanding of the pathogenicity of these viruses.
  19. Mariapun S, Li J, Yip CH, Taib NA, Teo SH
    PLoS ONE, 2015;10(2):e0117568.
    PMID: 25659139 DOI: 10.1371/journal.pone.0117568
    BACKGROUND: Mammographic density is a strong risk factor for breast cancer and is highly variable, but, to date, few studies have examined density in Asian women, particularly those in low and middle-income Asian countries where genetic and lifestyle determinants may be significantly different.
    METHODS: A total of 1,240 women who attended an opportunistic mammogram screening programme were eligible for analysis. Mammographic density was estimated using a fully-automated thresholding method and differences across ethnic groups were examined using linear regression in 205 randomly selected Chinese women, 138 Malay and 199 Indian women.
    RESULTS: Percent density was significantly higher in Chinese women (28.5%; 95% CI 27.0%, 30.0%) compared to Malay (24.2%; 95% CI 22.5%, 26.0%) and Indian (24.3%; 95% CI 22.8%, 25.7%) women (p<0.001), after adjustment for age, BMI, menopausal status, parity and age at first full term pregnancy. Correspondingly, adjusted nondense area was significantly lower in Chinese (72.2cm2; 95% CI 67.9cm2, 76.5cm2) women compared to Malay (92.1cm2; 95% CI 86.9cm2, 97.2cm2) and Indian (97.7cm2; 95% CI 93.4cm2, 101.9cm2) women (p<0.001), but dense area did not differ across the three ethnic groups.
    CONCLUSIONS: Our study shows that higher percent density and lower nondense area reflect the higher incidence of breast cancer in Chinese compared to Malay and Indian women in Malaysia. Known lifestyle determinants of mammographic density do not fully account for the ethnic variations observed in mammographic density in this Asian cohort.
  20. Yang Y, Li J, Yang S, Li X, Fang L, Zhong C, et al.
    BMC Evol. Biol., 2017 01 18;17(1):22.
    PMID: 28100168 DOI: 10.1186/s12862-016-0849-z
    BACKGROUND: A large-scale systematical investigation of the influence of Pleistocene climate oscillation on mangrove population dynamics could enrich our knowledge about the evolutionary history during times of historical climate change, which in turn may provide important information for their conservation.

    RESULTS: In this study, phylogeography of a mangrove tree Sonneratia alba was studied by sequencing three chloroplast fragments and seven nuclear genes. A low level of genetic diversity at the population level was detected across its range, especially at the range margins, which was mainly attributed to the steep sea-level drop and associated climate fluctuations during the Pleistocene glacial periods. Extremely small effective population size (Ne) was inferred in populations from both eastern and western Malay Peninsula (44 and 396, respectively), mirroring the fragility of mangrove plants and their paucity of robustness against future climate perturbations and human activity. Two major genetic lineages of high divergence were identified in the two mangrove biodiversity centres: the Indo-Malesia and Australasia regions. The estimated splitting time between these two lineages was 3.153 million year ago (MYA), suggesting a role for pre-Pleistocene events in shaping the major diversity patterns of mangrove species. Within the Indo-Malesia region, a subdivision was implicated between the South China Sea (SCS) and the remaining area with a divergence time of 1.874 MYA, corresponding to glacial vicariance when the emerged Sunda Shelf halted genetic exchange between the western and eastern coasts of the Malay Peninsula during Pleistocene sea-level drops. Notably, genetic admixture was observed in populations at the boundary regions, especially in the two populations near the Malacca Strait, indicating secondary contact between divergent lineages during interglacial periods. These interregional genetic exchanges provided ample opportunity for the re-use of standing genetic variation, which could facilitate mangrove establishment and adaptation in new habitats, especially in the context of global climate changes.

    CONCLUSION: Phylogeogrpahic analysis in this study reveal that Pleistocene sea-level fluctuations had profound influence on population differentiation of the mangrove tree S. alba. Our study highlights the fragility of mangrove plants and offers a guide for the conservation of coastal mangrove communities experiencing ongoing changes in sea-level.

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