Displaying publications 1 - 20 of 58 in total

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  1. Xu X, Liu F, Chen J, Ono H, Li D, Kuntner M
    Zookeys, 2015.
    PMID: 25878527 DOI: 10.3897/zookeys.488.8726
    The spider suborder Mesothelae, containing a single extant family Liphistiidae, represents a species-poor and ancient lineage. These are conspicuous spiders that primitively retain a segmented abdomen and appendage-like spinnerets. While their classification history is nearly devoid of phylogenetic hypotheses, we here revise liphistiid genus level taxonomy based on original sampling throughout their Asian range, and on the evidence from a novel molecular phylogeny. By combining morphological and natural history evidence with phylogenetic relationships in the companion paper, we provide strong support for the monophyly of Liphistiidae, and the two subfamilies Liphistiinae and Heptathelinae. While the former only contains Liphistius Schiödte, 1849, a genus distributed in Indonesia (Sumatra), Laos, Malaysia, Myanmar, Thailand, we recognize and diagnose seven heptatheline genera, all but three removed from the synonymy of Heptathela: i) Ganthela Xu & Kuntner, gen. n. with the type species Ganthelayundingensis Xu, sp. n. is known from Fujian and Jiangxi, China; ii) a rediagnosed Heptathela Kishida, 1923 is confined to the Japanese islands (Kyushu and Okinawa); iii) Qiongthela Xu & Kuntner, gen. n. with the type species Qiongthelabaishensis Xu, sp. n. is distributed disjunctly in Hainan, China and Vietnam; iv) Ryuthela Haupt, 1983 is confined to the Ryukyu archipelago (Japan); v) Sinothela Haupt, 2003 inhabits Chinese areas north of Yangtze; vi) Songthela Ono, 2000 inhabits southwest China and northern Vietnam; and vii) Vinathela Ono, 2000 (Abcathela Ono, 2000, syn. n.; Nanthela Haupt, 2003, syn. n.) is known from southeast China and Vietnam.
  2. Chen MX, Zhang RL, Xu XN, Yu Q, Huang DN, Liu W, et al.
    Trop Biomed, 2020 Mar 01;37(1):50-57.
    PMID: 33612717
    A 24-year-old man born in Guizhou province was diagnosed with obstructive jaundice and bile duct stones in 2013. Four living trematodes were found during laparotomy and cholecystectomy. Based on the morphology and molecular genetics analysis of internal transcribed spacer and pcox1 genes of the flatworm specimens, the trematodes from the patient were confirmed to be Fasciola hepatica. This report provided the clinical and molecular diagnosis information on human fascioliasis, which is an emerging sanitary problem still ignored in China. Human fascioliasis constantly occurs due to climatic changes and frequency of human travel. Therefore, it deserves more attention from physicians working in both developing and developed countries.
  3. Ge L, Li B, Li G, Wang X, Cheong KY, Peng Y, et al.
    J Phys Chem Lett, 2023 Jan 19;14(2):592-597.
    PMID: 36633457 DOI: 10.1021/acs.jpclett.2c03637
    This paper presents a fabricated solar-blind phototransistor based on hydrogen-terminated diamond. The phototransistor shows a large photocurrent and enhancement of responsivity over conventional two-terminal diamond-based photodetector. These enhancement effects are owing to the internal gain of the phototransistor. The fabricated phototransistor exhibits a high photoresponsivity (R) of 2.16 × 104 A/W and a detectivity (D*) of 9.63 × 1011 jones, with gate voltage (VG) and drain voltage of approximately -1.5 V and -5 V, respectively, under 213 nm light illumination. Even at ultralow operating voltage of -0.01 V, the device records satisfactory performance with R and D* of 146.7 A/W and 6.19 × 1010 jones, respectively. By adjusting the VG, photocurrent generation in the device can be continuously tuned from the fast photoconductive effect to the optical gating effect with high optical gain. When VG increases from 1.4 to 2.4 V, the decay time decreases from 1512.0 to 25.5 ms. Therefore, responsivity, dark current, Iphoto/Idark, and decay time of the device can be well tuned by VG.
  4. Liang Y, Jin X, Xu X, Wu Y, Ghfar AA, Lam SS, et al.
    Sci Total Environ, 2024 Feb 20;912:168873.
    PMID: 38016558 DOI: 10.1016/j.scitotenv.2023.168873
    Potentially toxic metal-polluted water resources are a heavily discussed topic the pollution by potentially toxic metals can cause significant health risks. Nanomaterials are actively developed towards providing high specific surface area and creating active adsorption sites for the treatment and remediation of these polluted waters. In an effort to tackle the limitations of conventional type adsorbents, nano-hydroxyapatite (HAp) was developed in this study by in situ generation onto wood powder, resulting in the formation of uniform hybrid powder (HAp@wood composite) structure consisting of HAp nanoparticles that showed the removal efficiency up to 80 % after 10 min; the maximum adsorption capacity for Cu(II) ions (98.95 mg/g-HAp) was higher compared to agglomerated nano-HAp (72.85 mg/g-HAp). The adsorption capacity of Cu(II) remained stable (89.85-107.66 mg/g-HAp) during the four adsorption-desorption cycles in multi-component system, thereby demonstrating high selectivity for Cu(II). This approach of using nanoparticle is relatively simple yet effective in improving the adsorption of potentially toxic metals and the developed approach can be used to develop advanced nanocomposites in commercial wastewater treatment.
  5. McDowell N, Allen CD, Anderson-Teixeira K, Brando P, Brienen R, Chambers J, et al.
    New Phytol, 2018 08;219(3):851-869.
    PMID: 29451313 DOI: 10.1111/nph.15027
    Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework with testable hypotheses regarding the drivers, mechanisms and interactions that may underlie increasing MTF mortality rates, and identify the next steps for improved understanding and reduced prediction. Increasing mortality rates are associated with rising temperature and vapor pressure deficit, liana abundance, drought, wind events, fire and, possibly, CO2 fertilization-induced increases in stand thinning or acceleration of trees reaching larger, more vulnerable heights. The majority of these mortality drivers may kill trees in part through carbon starvation and hydraulic failure. The relative importance of each driver is unknown. High species diversity may buffer MTFs against large-scale mortality events, but recent and expected trends in mortality drivers give reason for concern regarding increasing mortality within MTFs. Models of tropical tree mortality are advancing the representation of hydraulics, carbon and demography, but require more empirical knowledge regarding the most common drivers and their subsequent mechanisms. We outline critical datasets and model developments required to test hypotheses regarding the underlying causes of increasing MTF mortality rates, and improve prediction of future mortality under climate change.
  6. Muhamad HM, Xu X, Zhang X, Jaaman SA, Muda AM
    J Acoust Soc Am, 2018 05;143(5):2708.
    PMID: 29857727 DOI: 10.1121/1.5036926
    Studies of Irrawaddy dolphins' acoustics assist in understanding the behaviour of the species and thereby conservation of this species. Whistle signals emitted by Irrawaddy dolphin within the Bay of Brunei in Malaysian waters were characterized. A total of 199 whistles were analysed from seven sightings between January and April 2016. Six types of whistles contours named constant, upsweep, downsweep, concave, convex, and sine were detected when the dolphins engaged in traveling, foraging, and socializing activities. The whistle durations ranged between 0.06 and 3.86 s. The minimum frequency recorded was 443 Hz [Mean = 6000 Hz, standard deviation (SD) = 2320 Hz] and the maximum frequency recorded was 16 071 Hz (Mean = 7139 Hz, SD = 2522 Hz). The mean frequency range (F.R.) for the whistles was 1148 Hz (Minimum F.R. = 0 Hz, Maximum F.R. = 4446 Hz; SD = 876 Hz). Whistles in the Bay of Brunei were compared with population recorded from the waters of Matang and Kalimantan. The comparisons showed differences in whistle duration, minimum frequency, start frequency, and number of inflection point. Variation in whistle occurrence and frequency may be associated with surface behaviour, ambient noise, and recording limitation. This will be an important element when planning a monitoring program.
  7. Xu X, Smith CB, Mungall BA, Lindstrom SE, Hall HE, Subbarao K, et al.
    J Infect Dis, 2002 Nov 15;186(10):1490-3.
    PMID: 12404167
    Reassortant influenza A viruses bearing the H1 subtype of hemagglutinin (HA) and the N2 subtype of neuraminidase (NA) were isolated from humans in the United States, Canada, Singapore, Malaysia, India, Oman, Egypt, and several countries in Europe during the 2001-2002 influenza season. The HAs of these H1N2 viruses were similar to that of the A/New Caledonia/20/99(H1N1) vaccine strain both antigenically and genetically, and the NAs were antigenically and genetically related to those of recent human H3N2 reference strains, such as A/Moscow/10/99(H3N2). All 6 internal genes of the H1N2 reassortants examined originated from an H3N2 virus. This article documents the first widespread circulation of H1N2 reassortants on 4 continents. The current influenza vaccine is expected to provide good protection against H1N2 viruses, because it contains the A/New Caledonia/20/99(H1N1) and A/Moscow/10/99(H3N2)-like viruses, which have H1 and N2 antigens that are similar to those of recent H1N2 viruses.
  8. Xu X, Su YC, Ho SYW, Kuntner M, Ono H, Liu F, et al.
    Syst Biol, 2021 Oct 13;70(6):1110-1122.
    PMID: 33367903 DOI: 10.1093/sysbio/syaa098
    The segmented trapdoor spiders (Liphistiidae) are the sole surviving family of the suborder Mesothelae, which forms the sister lineage to all other living spiders. Liphistiids have retained a number of plesiomorphic traits and their present-day distribution is limited to East and Southeast Asia. Studying this group has the potential to shed light on the deep evolutionary history of spiders, but the phylogeny and divergence times of the family have not been resolved with confidence. We performed phylogenomic and molecular dating analyses of 2765 ultraconserved element loci from 185 liphistiid taxa. Our analyses show that the crown group of Liphistiidae appeared in the mid-Cretaceous at 102 Ma (95% credibility interval 92-113 Ma), but it was not until the Neogene that much of the diversification within the family occurred in mainland Southeast and East Asia. This diversification was coincident with tectonic events such as the extension of the East Asian continental margin, as well as geological upheavals in Indochina induced by the collision between India and Asia. Our study highlights the important role of major tectonic events in shaping the evolutionary history, present-day diversity, and geographical distribution of mesothele and liphistiid spiders. [biogeography; concatenation; Liphistiidae; molecular dating; summary coalescent; UCEs.].
  9. Li M, Mathai A, Lau SLH, Yam JW, Xu X, Wang X
    Sensors (Basel), 2021 Jan 05;21(1).
    PMID: 33466530 DOI: 10.3390/s21010313
    Due to medium scattering, absorption, and complex light interactions, capturing objects from the underwater environment has always been a difficult task. Single-pixel imaging (SPI) is an efficient imaging approach that can obtain spatial object information under low-light conditions. In this paper, we propose a single-pixel object inspection system for the underwater environment based on compressive sensing super-resolution convolutional neural network (CS-SRCNN). With the CS-SRCNN algorithm, image reconstruction can be achieved with 30% of the total pixels in the image. We also investigate the impact of compression ratios on underwater object SPI reconstruction performance. In addition, we analyzed the effect of peak signal to noise ratio (PSNR) and structural similarity index (SSIM) to determine the image quality of the reconstructed image. Our work is compared to the SPI system and SRCNN method to demonstrate its efficiency in capturing object results from an underwater environment. The PSNR and SSIM of the proposed method have increased to 35.44% and 73.07%, respectively. This work provides new insight into SPI applications and creates a better alternative for underwater optical object imaging to achieve good quality.
  10. Bi Y, Xu X, Chua SY, Chow EMT, Wang X
    Sensors (Basel), 2018 Mar 07;18(3).
    PMID: 29518889 DOI: 10.3390/s18030798
    Laser sensing has been applied in various underwater applications, ranging from underwater detection to laser underwater communications. However, there are several great challenges when profiling underwater turbulence effects. Underwater detection is greatly affected by the turbulence effect, where the acquired image suffers excessive noise, blurring, and deformation. In this paper, we propose a novel underwater turbulence detection method based on a gated wavefront sensing technique. First, we elaborate on the operating principle of gated wavefront sensing and wavefront reconstruction. We then setup an experimental system in order to validate the feasibility of our proposed method. The effect of underwater turbulence on detection is examined at different distances, and under different turbulence levels. The experimental results obtained from our gated wavefront sensing system indicate that underwater turbulence can be detected and analyzed. The proposed gated wavefront sensing system has the advantage of a simple structure and high detection efficiency for underwater environments.
  11. Yu H, Xing YT, Meng H, He B, Li WJ, Qi XZ, et al.
    Sci Adv, 2021 Jun;7(26).
    PMID: 34162544 DOI: 10.1126/sciadv.abg0221
    The Qinghai-Tibet Plateau endemic Chinese mountain cat has a controversial taxonomic status, whether it is a true species or a wildcat (Felis silvestris) subspecies and whether it has contributed to cat (F. s. catus) domestication in East Asia. Here, we sampled F. silvestris lineages across China and sequenced 51 nuclear genomes, 55 mitogenomes, and multilocus regions from 270 modern or museum specimens. Genome-wide analyses classified the Chinese mountain cat as a wildcat conspecific F. s. bieti, which was not involved in cat domestication of China, thus supporting a single domestication origin arising from the African wildcat (F. s. lybica). A complex hybridization scenario including ancient introgression from the Asiatic wildcat (F. s. ornata) to F. s. bieti, and contemporary gene flow between F. s. bieti and sympatric domestic cats that are likely recent Plateau arrivals, raises the prospect of disrupted wildcat genetic integrity, an issue with profound conservation implications.
  12. Xu X, Liu F, Cheng RC, Chen J, Xu X, Zhang Z, et al.
    Proc Biol Sci, 2015 Jun 07;282(1808):20142486.
    PMID: 25948684 DOI: 10.1098/rspb.2014.2486
    Living fossils are lineages that have retained plesiomorphic traits through long time periods. It is expected that such lineages have both originated and diversified long ago. Such expectations have recently been challenged in some textbook examples of living fossils, notably in extant cycads and coelacanths. Using a phylogenetic approach, we tested the patterns of the origin and diversification of liphistiid spiders, a clade of spiders considered to be living fossils due to their retention of arachnid plesiomorphies and their exclusive grouping in Mesothelae, an ancient clade sister to all modern spiders. Facilitated by original sampling throughout their Asian range, we here provide the phylogenetic framework necessary for reconstructing liphistiid biogeographic history. All phylogenetic analyses support the monophyly of Liphistiidae and of eight genera. As the fossil evidence supports a Carboniferous Euramerican origin of Mesothelae, our dating analyses postulate a long eastward over-land dispersal towards the Asian origin of Liphistiidae during the Palaeogene (39-58 Ma). Contrary to expectations, diversification within extant liphistiid genera is relatively recent, in the Neogene and Late Palaeogene (4-24 Ma). While no over-water dispersal events are needed to explain their evolutionary history, the history of liphistiid spiders has the potential to play prominently in vicariant biogeographic studies.
  13. Yang F, Xu X, Wang W, Ma J, Wei D, He P, et al.
    PLoS One, 2017;12(5):e0177509.
    PMID: 28498839 DOI: 10.1371/journal.pone.0177509
    Estimating balanced nutrient requirements for soybean (Glycine max [L.] Merr) in China is essential for identifying optimal fertilizer application regimes to increase soybean yield and nutrient use efficiency. We collected datasets from field experiments in major soybean planting regions of China between 2001 and 2015 to assess the relationship between soybean seed yield and nutrient uptake, and to estimate nitrogen (N), phosphorus (P), and potassium (K) requirements for a target yield of soybean using the quantitative evaluation of the fertility of tropical soils (QUEFTS) model. The QUEFTS model predicted a linear-parabolic-plateau curve for the balanced nutrient uptake with a target yield increased from 3.0 to 6.0 t ha-1 and the linear part was continuing until the yield reached about 60-70% of the potential yield. To produce 1000 kg seed of soybean in China, 55.4 kg N, 7.9 kg P, and 20.1 kg K (N:P:K = 7:1:2.5) were required in the above-ground parts, and the corresponding internal efficiencies (IE, kg seed yield per kg nutrient uptake) were 18.1, 126.6, and 49.8 kg seed per kg N, P, and K, respectively. The QUEFTS model also simulated that a balanced N, P, and K removal by seed which were 48.3, 5.9, and 12.2 kg per 1000 kg seed, respectively, accounting for 87.1%, 74.1%, and 60.8% of the total above-ground parts, respectively. These results were conducive to make fertilizer recommendations that improve the seed yield of soybean and avoid excessive or deficient nutrient supplies. Field validation indicated that the QUEFTS model could be used to estimate nutrient requirements which help develop fertilizer recommendations for soybean.
  14. Xu X, Rogers RA
    PLoS One, 2023;18(3):e0275625.
    PMID: 36893159 DOI: 10.1371/journal.pone.0275625
    After the cold war, some countries gradually seek to regional cooperation when they could not handle various transnational challenges alone. Shanghai Cooperation Organization (SCO) is a good example. It brought Central Asian countries together. This paper applies the text-mining method, using co-word analysis, co-occurrence matrix, cluster analysis, and strategic diagram to analyze the selected articles from newspapers quantitatively and visually. In order to investigate the Chinese government's attitude toward the SCO, this study collected data from the China Core Newspaper Full-text Database, which contains high-impact government newspapers revealing the Chinese government's perception of the SCO. This study characterizes the changing role of SCO as perceived by the Chinese government from 2001 to 2019. Beijing's changing expectations in each of the three identified subperiods are described.
  15. Costa H, Xu X, Overbeek G, Vasaikar S, Patro CP, Kostopoulou ON, et al.
    Oncotarget, 2016 Jul 26;7(30):47221-47231.
    PMID: 27363017 DOI: 10.18632/oncotarget.9722
    BACKGROUND: Both arginase (ARG2) and human cytomegalovirus (HCMV) have been implicated in tumorigenesis. However, the role of ARG2 in the pathogenesis of glioblastoma (GBM) and the HCMV effects on ARG2 are unknown. We hypothesize that HCMV may contribute to tumorigenesis by increasing ARG2 expression.

    RESULTS: ARG2 promotes tumorigenesis by increasing cellular proliferation, migration, invasion and vasculogenic mimicry in GBM cells, at least in part due to overexpression of MMP2/9. The nor-NOHA significantly reduced migration and tube formation of ARG2-overexpressing cells. HCMV immediate-early proteins (IE1/2) or its downstream pathways upregulated the expression of ARG2 in U-251 MG cells. Immunostaining of GBM tissue sections confirmed the overexpression of ARG2, consistent with data from subsets of Gene Expression Omnibus. Moreover, higher levels of ARG2 expression tended to be associated with poorer survival in GBM patient by analyzing data from TCGA.

    METHODS: The role of ARG2 in tumorigenesis was examined by proliferation-, migration-, invasion-, wound healing- and tube formation assays using an ARG2-overexpressing cell line and ARG inhibitor, N (omega)-hydroxy-nor-L-arginine (nor-NOHA) and siRNA against ARG2 coupled with functional assays measuring MMP2/9 activity, VEGF levels and nitric oxide synthase activity. Association between HCMV and ARG2 were examined in vitro with 3 different GBM cell lines, and ex vivo with immunostaining on GBM tissue sections. The viral mechanism mediating ARG2 induction was examined by siRNA approach. Correlation between ARG2 expression and patient survival was extrapolated from bioinformatics analysis on data from The Cancer Genome Atlas (TCGA).

    CONCLUSIONS: ARG2 promotes tumorigenesis, and HCMV may contribute to GBM pathogenesis by upregulating ARG2.

  16. Kunaviktikul W, Ang E, Baridwan NS, Bernal AB, Dones LBP, Flores JL, et al.
    Nurse Educ Today, 2022 Apr;111:105307.
    PMID: 35217457 DOI: 10.1016/j.nedt.2022.105307
    BACKGROUND: The COVID-19 pandemic has caused extraordinary disruptions to education systems globally, forcing a rapid switch from conventional to online education. Although some qualitative studies have been carried out exploring the online education experiences of nursing students and faculty members during the COVID-19 pandemic, to our knowledge, no study has used the Photovoice approach.

    OBJECTIVES: To explore the experiences of nursing students and faculty members as related to online education during the COVID-19 pandemic.

    DESIGN: A descriptive qualitative design using Photovoice was adopted.

    SETTING: The study took place across five countries and one city in Southeast Asia (Indonesia, Malaysia, the Philippines, Thailand, Vietnam, and Hong Kong).

    PARTICIPANTS: Fifty-two nursing students and twenty-eight nursing faculty members who participated in online education during the COVID-19 pandemic.

    METHODS: Each participant submitted one photo substantiated with written reflections. Data were analysed using thematic analysis. Ethical approval was obtained from institution-specific ethics boards.

    RESULTS: Three themes and eleven sub-themes emerged from the data. The three main themes were: 1) Psychological roadblocks to online education; 2) Developing resilience despite adversities; and 3) Online education: What worked and what did not.

    CONCLUSION: Through Photovoice, the reflections revealed that nursing students and faculty members were generally overwhelmed with the online education experience. At the same time, participants were satisfied with the flexibility and convenience, opportunities for professional and personal development and safety afforded by online education. However, concerns over academic integrity, practical skills and clinical competencies, engagement and participation, the duality of technology and social isolation out-shadowed the advantages. It is worthwhile to explore the concerns raised to enhance online education across the nursing curriculum.

  17. Shorey S, Ang E, Baridwan NS, Bonito SR, Dones LBP, Flores JLA, et al.
    Nurse Educ Today, 2022 Mar;110:105277.
    PMID: 35101809 DOI: 10.1016/j.nedt.2022.105277
    BACKGROUND: The COVID-19 pandemic has disrupted the lives of many. Particularly, nursing students experience greater stress as their normal curriculum is interrupted and some of them face the risk of being infected as frontline workers. Nursing faculty members may face similar struggles, in addition to developing teaching materials for online learning. Thus, it is important to examine the faculty members' and students' views on their ability to adapt during the pandemic to obtain a holistic view of how learning and training has been affected.

    DESIGN: The descriptive cross-sectional quantitative design was used.

    SETTINGS: Data were collected from Southeast and East Asian Nursing Education and Research Network (SEANERN) affiliated nursing institutions from January 2021 to August 2021.

    PARTICIPANTS: A total of 1897 nursing students and 395 faculty members from SEANERN-affiliated nursing institutions in Cambodia, Hong Kong, Indonesia, Japan, Laos, Malaysia, Philippines, Singapore, Thailand and Vietnam were recruited for this study.

    METHODS: Quantitative surveys were used to explore the satisfaction levels in education modalities, confidence levels, psychosocial well-being, sense of coherence and stress levels of nursing students and faculty members during the COVID-19 pandemic.

    RESULTS: Participants were mostly satisfied with the new education modalities, although most students felt that their education was compromised. Both groups showed positive levels of psychosocial well-being, despite scoring low to medium on the sense of coherence scale and experiencing great stress. The participants' sense of coherence was positively correlated with their psychosocial well-being and negatively correlated with stress levels.

    CONCLUSIONS: While the COVID-19 pandemic had negatively impacted the lives of nursing students and faculty members, most of them had a healthy level of psychosocial well-being. Having a strong sense of coherence was associated with better psychosocial health and lower stress levels. As such, it may be helpful to develop interventions aimed at improving the sense of coherence of nursing students and staff to help them manage stressors better.

  18. Grove J, Ripke S, Als TD, Mattheisen M, Walters RK, Won H, et al.
    Nat Genet, 2019 03;51(3):431-444.
    PMID: 30804558 DOI: 10.1038/s41588-019-0344-8
    Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD.
  19. Sun X, Liu YC, Tiunov MP, Gimranov DO, Zhuang Y, Han Y, et al.
    Nat Ecol Evol, 2023 Nov;7(11):1914-1929.
    PMID: 37652999 DOI: 10.1038/s41559-023-02185-8
    The tiger (Panthera tigris) is a charismatic megafauna species that originated and diversified in Asia and probably experienced population contraction and expansion during the Pleistocene, resulting in low genetic diversity of modern tigers. However, little is known about patterns of genomic diversity in ancient populations. Here we generated whole-genome sequences from ancient or historical (100-10,000 yr old) specimens collected across mainland Asia, including a 10,600-yr-old Russian Far East specimen (RUSA21, 8× coverage) plus six ancient mitogenomes, 14 South China tigers (0.1-12×) and three Caspian tigers (4-8×). Admixture analysis showed that RUSA21 clustered within modern Northeast Asian phylogroups and partially derived from an extinct Late Pleistocene lineage. While some of the 8,000-10,000-yr-old Russian Far East mitogenomes are basal to all tigers, one 2,000-yr-old specimen resembles present Amur tigers. Phylogenomic analyses suggested that the Caspian tiger probably dispersed from an ancestral Northeast Asian population and experienced gene flow from southern Bengal tigers. Lastly, genome-wide monophyly supported the South China tiger as a distinct subspecies, albeit with mitochondrial paraphyly, hence resolving its longstanding taxonomic controversy. The distribution of mitochondrial haplogroups corroborated by biogeographical modelling suggested that Southwest China was a Late Pleistocene refugium for a relic basal lineage. As suitable habitat returned, admixture between divergent lineages of South China tigers took place in Eastern China, promoting the evolution of other northern subspecies. Altogether, our analysis of ancient genomes sheds light on the evolutionary history of tigers and supports the existence of nine modern subspecies.
  20. Qiu C, Zhang Z, Li X, Sang S, McClements DJ, Chen L, et al.
    NPJ Sci Food, 2023 Jun 14;7(1):29.
    PMID: 37316567 DOI: 10.1038/s41538-023-00186-2
    In this study, composite nanoparticles consisting of zein and hydroxypropyl beta-cyclodextrin were prepared using a combined antisolvent co-precipitation/electrostatic interaction method. The effects of calcium ion concentration on the stability of the composite nanoparticles containing both curcumin and quercetin were investigated. Moreover, the stability and bioactivity of the quercetin and curcumin were characterized before and after encapsulation. Fluorescence spectroscopy, Fourier Transform infrared spectroscopy, and X-ray diffraction analyses indicated that electrostatic interactions, hydrogen bonding, and hydrophobic interactions were the main driving forces for the formation of the composite nanoparticles. The addition of calcium ions promoted crosslinking of the proteins and affected the stability of the protein-cyclodextrin composite particles through electrostatic screening and binding effects. The addition of calcium ions to the composite particles improved the encapsulation efficiency, antioxidant activity, and stability of the curcumin and quercetin. However, there was an optimum calcium ion concentration (2.0 mM) that provided the best encapsulation and protective effects on the nutraceuticals. The calcium crosslinked composite particles were shown to maintain good stability under different pH and simulated gastrointestinal digestion conditions. These results suggest that zein-cyclodextrin composite nanoparticles may be useful plant-based colloidal delivery systems for hydrophobic bio-active agents.
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