Publications by authors named "Khiem Nguyen"

Accurate and cost-effective prediction of aboveground biomass (AGB), belowground biomass (BGB), and the total (ABGB) at stand-level within tropical forests is crucial for effective forest ecological management and the provision of forest ecosystem services. Although there has been research on simultaneously fitting biomass equations for tree components, rather few studies focus on simultaneously predicting AGB and BGB at stand-level while maintaining additivity. We developed innovative Deep Learning Additive Models (DLAMs) for the simultaneous predictions of stand-level AGB, BGB, and ABGB integrating forest stand, ecological, and environmental factors as predictive covariates and compared them with conventional weighted nonlinear seemingly unrelated regression (WNSUR) and multivariate adaptive regression splines (MARS).

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Consecutive interactions of 3Na or 1Ca with the Na/Ca exchanger (NCX) result in an alternative exposure (access) of the cytosolic and extracellular vestibules to opposite sides of the membrane, where ion-induced transitions between the outward-facing (OF) and inward-facing (IF) conformational states drive a transport cycle. Here, we investigate sub-state populations of apo and ion-bound species in the OF and IF states by analyzing detergent-solubilized and nanodisc-reconstituted preparations of NCX_Mj with F-NMR. The F probe was covalently attached to the cysteine residues at entry locations of the cytosolic and extracellular vestibules.

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Article Synopsis
  • Spaceflight triggers an immune response in astronauts, which was analyzed during the SpaceX Inspiration4 mission using various data types, including single-cell and biochemical analysis.
  • Researchers identified a "spaceflight signature" in gene expression linked to processes like oxidative phosphorylation, immune function, and inflammation, found across multiple datasets.
  • Key findings include up-regulation of specific immune markers in T cells, long-term suppression of certain MHC class I genes, and changes in infection-related immune pathways due to shifts in the microbiome.
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Microgravity is associated with immunological dysfunction, though the mechanisms are poorly understood. Here, using single-cell analysis of human peripheral blood mononuclear cells (PBMCs) exposed to short term (25 hours) simulated microgravity, we characterize altered genes and pathways at basal and stimulated states with a Toll-like Receptor-7/8 agonist. We validate single-cell analysis by RNA sequencing and super-resolution microscopy, and against data from the Inspiration-4 (I4) mission, JAXA (Cell-Free Epigenome) mission, Twins study, and spleens from mice on the International Space Station.

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Article Synopsis
  • - Aging negatively affects the adaptive immune system, leading to fewer diverse T cells and an increase in inflammatory T cell types, which are linked to chronic diseases and higher mortality rates.
  • - B cells play a significant role in the aging process of T cells by reducing naive T cells and promoting harmful T cell subsets, as shown through various experimental models and single-cell analysis.
  • - Targeting these age-related changes in T cells with CD20 monoclonal antibody treatment could help improve immune function and healthspan, with insulin receptor signaling identified as a key mechanism behind B cell effects on T cell dysfunction.
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Article Synopsis
  • Uveitis is a serious inflammation of the uveal tract that can lead to blindness and has significant impacts on patients and society, particularly in developed countries.
  • Despite various treatments, noninfectious posterior segment uveitis remains difficult to manage due to its severity and tendency to recur.
  • New biologic drugs show promise and may outperform traditional immunosuppressive therapies, but more research and clinical trials are necessary to optimize treatment strategies.
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Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome and Stevens-Johnson Syndrome (SJS) are severe cutaneous adverse reactions to drugs. Those reactions which are rare in children can be especially severe and challenging to diagnose and manage. Herein we present a 59-month-old male who presented with a rash, fever, and multiple organ dysfunction initiation of Phenobarbital for epilepsy.

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A strategy for the synthesis of bacteriochlorophyll relies on joining AD and BC halves that contain the requisite stereochemical configurations of the target macrocycle. The BC half () is a dihydrodipyrrin bearing a dimethoxymethyl group at the 1-position, a β-ketoester at the 8-position, and ()-2-methyl and ()-3-ethyl substituents in the pyrroline ring. An established route to AD-dihydrodipyrrins (Pd-mediated coupling of a 2-halopyrrole with a chiral 4-pentynoic acid followed by Petasis methenylation, acidic hydrolysis, Paal-Knorr ring closure, and Riley oxidation) proved to be unviable for BC-dihydrodipyrrins given the presence of the β-ketoester unit.

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Intracellular binding of small-molecule phospho-Ags to the HMBPP receptor complex in infected cells leads to extracellular detection by T cells expressing the Vγ9Vδ2 TCR, a noncanonical method of Ag detection. The butyrophilin proteins BTN2A1 and BTN3A1 are part of the complex; however, their precise roles are unclear. We suspected that BTN2A1 and BTN3A1 form a tetrameric (dimer of dimers) structure, and we wanted to probe the importance of the BTN2A1 homodimer.

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Aging is characterized by a progressive loss of brain volume at an estimated rate of 5% per decade after age 40. While these morphometric changes, especially those affecting gray matter and atrophy of the temporal lobe, are predictors of cognitive performance, the strong association with aging obscures the potential parallel, but more specific role, of individual subject physiology. Here, we studied a cohort of 554 human subjects who were monitored using structural MRI scans and blood immune protein concentrations.

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Predicting the export price of shrimp is important for Vietnam's fisheries. It not only promotes product quality but also helps policy makers determine strategies to develop the national shrimp industry. Competition in global markets is considered to be an important factor, one that significantly influences price.

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The ligand-bound (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) receptor (BTN3A1 and BTN2A1) is detectable by the T cell receptor (TCR) of Vγ9Vδ2 T cells. Although BTN3A1 binds to phosphoantigens (pAgs), the mechanisms resulting in receptor activation are not clear. We used CRISPR-Cas9, ELISA, nano-bioluminescence resonance energy transfer (BRET), and isothermal titration calorimetry (ITC) to evaluate the role of BTN2A1.

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While many diseases of aging have been linked to the immunological system, immune metrics capable of identifying the most at-risk individuals are lacking. From the blood immunome of 1,001 individuals aged 8-96 years, we developed a deep-learning method based on patterns of systemic age-related inflammation. The resulting inflammatory clock of aging (iAge) tracked with multimorbidity, immunosenescence, frailty and cardiovascular aging, and is also associated with exceptional longevity in centenarians.

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Background: To investigate the knowledge, attitudes, and practices of the healthcare professionals (HCPs) including physicians and nurses regarding dengue transmission, diagnosis and clinical classification using the warning signs of World Health Organization (WHO) 2009 classification.

Results: Out of 471 respondents from three countries, 80.9% of physicians and 74% of nurses did not receive previous training regarding the dengue infection.

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Background: Pancreatic ductal adenocarcinoma (PDAC) has a high recurrence rate and poor outcome. Lymph node (LN) metastasis, especially para-aortic LN (PALN), is an important prognostic factor. PALN assessment through sampling with frozen-section analysis is a validated method.

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Challenges to the synthesis of bacteriochlorophyll (), the chief pigment for anoxygenic bacterial photosynthesis, include creating the macrocycle along with the -dialkyl substituents in both pyrroline rings (B and D). A known route to a model bacteriochlorophyll with a gem-dimethyl group in each pyrroline ring has been probed for utility in the synthesis of by preparation of a hybrid macrocycle (), which contains a -dialkyl group in ring D and a gem-dimethyl group in ring B. Stereochemical definition began with the synthesis of (2,3)-2-ethyl-3-methylpent-4-ynoic acid, a precursor to the -dialkyl-substituted AD dihydrodipyrrin.

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Gene-environment interactions (GxE) can be fundamental in applications ranging from functional genomics to precision medicine and is a conjectured source of substantial heritability. However, unbiased methods to profile GxE genome-wide are nascent and, as we show, cannot accommodate general environment variables, modest sample sizes, heterogeneous noise, and binary traits. To address this gap, we propose a simple, unifying mixed model for gene-environment interaction (GxEMM).

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An efficient cycloaddition of heterocyclic alkenes with nitrile oxides generated in situ from the corresponding aldoximes using organohypervalent iodine(III) reagent, [hydroxy(tosyloxy)iodo]benzene (Koser's reagent), has been developed. The oxidative cyclization of various aldoximes with 1-propene-1,3-sultone affords the respective isoxazoline-ring-fused heterobicyclic products in moderate to good yields. Furthermore, the reaction of aldoxime with a cyclic phospholene-oxide under similar conditions produces the corresponding heterobicyclic phospholene oxides in moderate yields.

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Small isoprenoid diphosphates, such as ()-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP), are ligands of the internal domain of BTN3A1. Ligand binding in target cells promotes activation of Vγ9Vδ2 T cells. We demonstrate by small-angle X-ray scattering (SAXS) that HMBPP binding to the internal domain of BTN3A1 induces a conformational change in the position of the B30.

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Nanodiscs provide an excellent system for the structure-function investigation of membrane proteins. Its direct advantage lies in presenting a water soluble form of an otherwise hydrophobic molecule, making it amenable to a plethora of solution techniques. Nuclear Magnetic Resonance is one such high resolution approach that looks at the structure and dynamics of a protein with atomic level precision.

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PLIC, Protein Linking IAP (CD47) to Cytoskeleton, have long since been implicated in connecting the extracellular membrane to the intracellular cell cytoskeleton. This phenomenon is supposedly achieved by bridging a receptor protein CD47 to vimentin, an intermediate filament, which in turn regulates integrin dependent cell spreading. Since the discovery of these proteins, the molecular details of the above-mentioned interactions and the underlying complexes are yet to be characterized.

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New pseudocyclic benziodoxole tosylates were prepared by the treatment of 1-hydroxybenziodoxolones with p-toluenesulfonic acid or via ligand transfer reaction between PhI(OH)OTs (Koser's reagent) and substituted 2-iodobenzoic acids under mild condition. Single crystal X-ray crystallography of these compounds revealed a pseudocyclic structure with a short intramolecular interaction of 2.362 Å between oxygen and iodine in the iodoxole ring.

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The functional properties of starches from six sweet potato varieties containing various starch components and structures were studied in an attempt to identify starch sources for industrial uses. Tainan 18 (TNN18) with high-amylose (AM) starch exhibited high setback and breakdown viscosities, high water solubility at 85°C but low swelling volume at 65°C, and high hardness and adhesiveness; in contrast, the low-AM starch of Tainung 31 (TNG31) had opposite characteristics. Seven genes related to starch biosynthesis were tested, and GBSS, SS, SBEII, ISA, and AGPase were highly expressed in TNN18 and TNG31; however, transcript levels in DBE and SBE were extremely low.

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We report the usage of DNA hydrogels for enzyme entrapment in an enzymatic biobattery. With the recent advancements in DNA nanotechnology, the incorporation of DNA materials to bioelectrocatalytic electrodes holds great promise to improve the performance of bioelectrocatalysis-based devices.

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