THE KAUST Repository is an initiative of the University Library to expand the impact of conference papers, technical reports, peer-reviewed articles, preprints, theses, images, data sets, and other research-related works of King Abdullah University of Science and Technology (KAUST).
Files in the repository are accessible through popular web search engines and are given persistent web addresses so links will not become broken over time.
KAUST researchers: To add your research to the repository, click on Deposit your Research, log in with your KAUST user name and password, and deposit the item in the appropriate collection.
If you have any questions, please contact firstname.lastname@example.org.
Sex ratio at birth in Vietnam among six subnational regions during 1980–2050, estimation and probabilistic projection using a Bayesian hierarchical time series model with 2.9 million birth records(PLOS ONE, Public Library of Science (PLoS), 2021-07-14) [Article]The sex ratio at birth (SRB, i.e., the ratio of male to female births) in Vietnam has been imbalanced since the 2000s. Previous studies have revealed a rapid increase in the SRB over the past 15 years and the presence of important variations across regions. More recent studies suggested that the nation’s SRB may have plateaued during the 2010s. Given the lack of exhaustive birth registration data in Vietnam, it is necessary to estimate and project levels and trends in the regional SRBs in Vietnam based on a reproducible statistical approach. We compiled an extensive database on regional Vietnam SRBs based on all publicly available surveys and censuses and used a Bayesian hierarchical time series mixture model to estimate and project SRB in Vietnam by region from 1980 to 2050. The Bayesian model incorporates the uncertainties from the observations and year-by-year natural fluctuation. It includes a binary parameter to detect the existence of sex ratio transitions among Vietnamese regions. Furthermore, we model the SRB imbalance using a trapezoid function to capture the increase, stagnation, and decrease of the sex ratio transition by Vietnamese regions. The model results show that four out of six Vietnamese regions, namely, Northern Midlands and Mountain Areas, Northern Central and Central Coastal Areas, Red River Delta, and South East, have existing sex imbalances at birth. The rise in SRB in the Red River Delta was the fastest, as it took only 12 years and was more pronounced, with the SRB reaching the local maximum of 1.146 with a 95% credible interval (1.129, 1.163) in 2013. The model projections suggest that the current decade will record a sustained decline in sex imbalances at birth, and the SRB should be back to the national SRB baseline level of 1.06 in all regions by the mid-2030s.
Diversity, host specificity and biogeography in the Cladocorynidae (Hydrozoa, Capitata), with description of a new genus(Cladistics, Wiley, 2021-07-14) [Article]The hydrozoan family Cladocorynidae inhabits tropical to temperate waters and comprises the two genera Pteroclava and Cladocoryne. Pteroclava lives in association with some octocorals and hydrozoans, whereas Cladocoryne is more generalist in terms of substrate choice. This work provides a thorough morpho-molecular reassessment of the Cladocorynidae by presenting the first well-supported phylogeny of the family based on the analyses of three mitochondrial and four nuclear markers. Notably, the two nominal genera were confirmed to be monophyletic and both morphological and genetic data led to the formal description of a new genus exclusively associated with octocorals, Pseudozanclea gen. nov. Maggioni & Montano. Accordingly, the diagnosis of the family was updated. The ancestral state reconstruction of selected characters revealed that the symbiosis with octocorals likely appeared in the most recent common ancestor of Pteroclava and Pseudozanclea. Additionally, the presence of euryteles aggregation in the polyp stage and the exumbrellar nematocyst pouches with euryteles represent synapomorphies of all cladocorynid taxa and probably emerged in their most recent common ancestor. The analysis of several Pteroclava krempfi colonies from Indo-Pacific and Caribbean localities associated with several host octocorals revealed a high intra-specific genetic variability. Single- and multi-locus species delimitations resulted in three to five species hypotheses, but the statistical analysis of morphometric data showed only limited distinction among the clades of P. krempfi. However, P. krempfi clades showed differences in both host specificity, mostly at the octocoral family level, and geographic distribution, with one clade found exclusively in the Caribbean Sea and the others found in the Indo-Pacific.
Single-molecule imaging and microfluidic platform reveal molecular mechanisms of leukemic cell rolling(Communications Biology, Springer Science and Business Media LLC, 2021-07-14) [Article]AbstractHematopoietic stem/progenitor cell (HSPC) and leukemic cell homing is an important biological phenomenon that occurs through key interactions between adhesion molecules. Tethering and rolling of the cells on endothelium, the crucial initial step of the adhesion cascade, is mediated by interactions between selectins expressed on endothelium to their ligands expressed on HSPCs/leukemic cells in flow. Although multiple factors that affect the rolling behavior of the cells have been identified, molecular mechanisms that enable the essential slow and stable cell rolling remain elusive. Here, using a microfluidics-based single-molecule live cell fluorescence imaging, we reveal that unique spatiotemporal dynamics of selectin ligands on the membrane tethers and slings, which are distinct from that on the cell body, play an essential role in the rolling of the cell. Our results suggest that the spatial confinement of the selectin ligands to the tethers and slings together with the rapid scanning of a large area by the selectin ligands, increases the efficiency of selectin-ligand interactions during cell rolling, resulting in slow and stable rolling of the cell on the selectins. Our findings provide novel insights and contribute significantly to the molecular-level understanding of the initial and essential step of the homing process.
Disentangling marine microbial networks across space(Cold Spring Harbor Laboratory, 2021-07-13) [Preprint]Although microbial interactions underpin ocean ecosystem functions, they remain barely known. Different studies have analyzed microbial interactions using static association networks based on omics-data. However, microbial associations are dynamic and can change across physicochemical gradients and spatial scales, which needs to be considered to understand the ocean ecosystem better. We explored associations between archaea, bacteria, and picoeukaryotes along the water column from the surface to the deep ocean across the northern subtropical to the southern temperate ocean and the Mediterranean Sea by defining sample-specific subnetworks. Quantifying spatial association recurrence, we found the lowest fraction of global associations in the bathypelagic zone, while associations endemic of certain regions increased with depth. Overall, our results highlight the need to study the dynamic nature of plankton networks and our approach represents a step forward towards a better comprehension of the biogeography of microbial interactions across ocean regions and depth layers.
[Cu36H10(PET)24(PPh3)6Cl2] Reveals Surface Vacancy Defects in Ligand-Stabilized Metal Nanoclusters(Journal of the American Chemical Society, American Chemical Society (ACS), 2021-07-13) [Article]Precise identification and in-depth understanding of defects in nanomaterials can aid in rationally modulating defect-induced functionalities. However, few studies have explored vacancy defects in ligand-stabilized metal nanoclusters with well-defined structures, owing to the substantial challenge of synthesizing and isolating such defective metal nanoclusters. Herein, a novel defective copper hydride nanocluster, [Cu36H10(PET)24(PPh3)6Cl2] (Cu36; PET: phenylethanethiolate; PPh3: triphenylphosphine), is successfully synthesized at the gram scale via a simple one-pot reduction method. Structural analysis reveals that Cu36 is a distorted half cubic nanocluster, evolved from the perfect Nichol’s half cube. The two surface copper vacancies in Cu36 are found to be the principal imperfections, which result in some structural adjustments, including copper atom reconstruction near the vacancies as well as ligand modifications (e.g., substitution, migration, and exfoliation). Density functional theory calculations imply that the above-mentioned defects have a considerable influence on the electronic structure and properties. The modeling suggests that the formation of defective Cu36 rather than the perfect half cube is driven by the enlargement of the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the nanocluster. The structural evolution induced by the surface copper atom vacancies provides atomically precise insights into the defect-induced readjustment of the local structure and introduces new avenues for understanding the chemistry of defects in nanomaterials.