The escalating wearable electronic devices with their flexible energy sources demand has rendered the imperative scientific challenge on the development of materials for the flexible triboelectric nanogenerators (F-TENG), one of advanced energy harvesting systems. Dielectric material optimization, the Y3+ donor-doped calcium copper titanate based on exactly stoichiometric Ca0.95Y0.05Cu3Ti4O12 (CCTYO), serves as a critical pathway in this work for achieving enhanced F-TENG via compositing with the polydimethylsiloxane (PDMS) polymer. The enhancement of electrical output has garnered substantial interest owing to its increased relative permittivity (epsilon(r)). The influence of the loaded CCTYO amounts on structure, morphologies, dielectric properties, and electrical output, including open-circuit voltage (V-OC), short-circuit current (I-SC) and power density for PDMS/CCTYO composites is investigated. As compared with loading undoped CCTO, the additional Y3+ can improve higher F-TENG output by increasing the along with maintaining the loss tangent (tan delta < 0.02) at optimized condition. The appropriate amounts of CCTYO 0.75 wt% make the PDMS/CCTYO F-TENG to achieve V-OC of similar to 76.4 V (8.5 V/cm(2)) and I-SC of similar to 130.0 mu A (14.4 mu A/cm(2)), which were higher than pristine PDMS for 2.7 and 4.3 times. The power density of 53 & micro;W/cm(2) is 8.9 times higher than that of 6.3 & micro;W/cm(2) from the pristine PDMS. This study also provides a COMSOL multiphysics simulation, bridging laboratory experiments, for quantifying the triboelectric capability of dielectric materials.
Max-plus algebra is a semiring with two operations: addition circle plus := max and multiplication (R) := +. The definition of the max-plus algebraic determinant is equivalent to the assignment problem on a bipartite graph. Since the assignment problem has a formulation as linear programming, the duality theorem induces the minimization problem that attains the same optimal value as the assignment problem. We translate this dual problem in terms of max-plus algebraic operation and obtain another expression for the max-plus algebraic determinant. For the determinant of the product of max-plus square matrices, we have only the inequality det(P (R) Q) >= det P (R) det Q, and a known sufficient condition for the equality is given by the condition for det(P (R) Q). Exploiting the duality theorem for the determinant, we derive a necessary and sufficient condition for the equality. Our criterion only needs the optimal assignments corresponding to det P and det Q but does not require to compute det(P (R) Q) beforehand.
Carbon dioxide removal (CDR) via enhanced rock weathering (ERW) strongly depends on rock particle size. While ERW models typically link finer particle size to greater CDR, their tendency to aggregate with soil components such as organic matter (OM) may impede weathering. The inconsistent effects of ERW on soil OM storage in recent studies reinforce the need to clarify underlying mechanisms. We thus tested if finer basaltic rock promotes organo-mineral association while lowering CDR through incubation experiments (rock alone and rock-plant residue-sand mixture) under water regimes with or without weekly leaching. After six months, we analyzed total carbon, extractable metal(loid)s, organo-mineral aggregate formation (by density fractionation), and inorganic carbon contents (by XANES and leachates). Coarse basaltic rock (106–150 μm) showed faster abiotic and biologically induced weathering. Contrarily, fine basaltic rock (20–38 μm) led to greater organo-mineral aggregation and OM accrual, which was attributable to higher particle numbers, geometric surface area, and binding agents (inherent and increased reactive metal(loid)s). The amount of organic carbon stabilized in meso-density aggregates by basaltic rock was one order of magnitude higher than the estimated CDR, regardless of the water regimes. These results exhibit the first direct evidence that rock particle size could induce the trade-off between CO2 removal and OM stabilization, which implies that the current ERW models may severely overestimate CDR potential due to basaltic rock interaction with OM and its weathering products. Further research into rock interactions with soil components is essential for improving model prediction and optimizing ERW applications.
Polychlorinated biphenyls (PCBs) are persistent environmental pollutants, whose hydroxylated metabolites (OH-PCBs) accumulate in humans and may exhibit more potent effects than their parent compounds. This study investigated serum concentrations of several persistent OH-PCBs and their parent PCBs in 129 Japanese participants, with a focus on the influence of the CYP2A6*4 gene deletion variant on OH-PCB formation in PCB metabolism. Blood samples (n = 129) were genotyped for CYP2A6 (*1, *4, *7, and *9) and CYP2B6 variants. OH-PCBs and PCBs were quantified by gas chromatography-mass spectrometry. Concentrations and metabolite-to-parent ratios were compared among three CYP2A6 genotype groups (*1/*1 as wild-type, *1/*4, *4/*4; n = 49) and multiple linear regression evaluated associations between CYP2A6 genotype and OH-PCB/PCB ratios, adjusting for CYP2B6 genotype, age, and body mass index. Jonckheere-Terpstra trend test showed significant genotype-dependent decreasing trends in metabolite-to-parent ratios of four of the six OH-PCBs to their parent PCBs (3'-OH-PCB138, 4-OH-PCB146, 3-OH-PCB153, 4-OH-PCB187). In multiple linear regression, carriers of CYP2A6 *4 showed significantly lower ratios for 3-OH-PCB153 to PCB-153 (β = -0.304 per *4 allele, 95 % CI: [-0.496, -0.112], p = 0.003) and 4-OH-PCB187 to PCB-187 (β = -0.093, 95 % CI: [-0.175, -0.011], p = 0.028). No significant decreasing trends were observed for other OH-PCBs after adjustment. In conclusion, the CYP2A6*4 loss-of-function variant is associated with reduced metabolic conversion of certain PCBs to OH-PCBs, suggesting that CYP2A6 genetic variation may modulate individual susceptibility to the health risks of PCB exposure.
Steviol glycosides (SGs), intensely sweet diterpenoids found in Stevia rebaudiana (stevia), exhibit natural variation in composition that influences taste quality and commercial value. However, the genetic and cellular mechanisms underlying this variation remain poorly understood. We aimed to uncover how haplotype-level diversity and cell-type-specific gene expression contribute to SG profile diversity in stevia. We generated a chromosome-scale reference genome and conducted integrative multi-omics analyses combining haplotype-resolved population genomics, single-nucleus RNA sequencing, and imaging mass spectrometry. These approaches were applied to a diverse panel of breeding lines and a segregating population to associate genetic variants with SG composition and expression patterns. We identified a physically linked cluster of UGT76G glycosyltransferase genes whose structural and regulatory polymorphisms drive major differences in SG composition. Restricted expression of UGT91D4 to specific subsets of mesophyll and epidermal cells further constrained the biosynthesis of high-value SGs, such as rebaudioside D and rebaudioside M. Functional divergence among UGT76G paralogs was supported by sequence, expression, and structural modeling data. Our findings define a multi-allelic and spatially coordinated regulatory architecture underlying SG biosynthesis in stevia. These insights provide a foundation for haplotype-guided breeding and metabolic engineering strategies aimed at improving stevia sweetness quality and yield.
