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Medicinal plants: are they safe enough for fish health?
Full text linkThe antipathogenic, immunomodulatory, and other beneficial properties of medicinal plants have made them a potentially ideal alternative to chemotherapeutic treatments for fish health. Therefore, medicinal plants as alternative therapeutics in fish have been regarded by many studies as healthy and safe because plants are “natural” and thus considered harmless. However, some toxicology studies raise concerns for these medicinal plants’ safety and implications for application on fish. These studies reveal that the plant application may lead to some potential health risks on fish. The aim of this review is to briefly summarize and discuss the adverse effects of medicinal plants on fish health
Controlling the morphology of polycrystalline diamond films via seed density: Influence on grain size and film texture
Full text linkControlling the morphology of polycrystalline diamond (PCD) films is crucial for various applications, including thermal management and quantum sensors. PCD films are typically produced by plasma-enhanced chemical vapor deposition on substrates seeded with nanodiamonds. Different film morphologies can be achieved by controlling growth rates of crystal-forming facets, which is commonly managed through deposition temperature and hydrocarbon concentration in the plasma. However, the impact of seed density on film morphology remains largely unexplored. In this study, we observed that reducing seed density on silicon substrates has a similar effect on PCD film morphology as increasing hydrocarbon concentration in the plasma. Specifically, as seed density decreases, deposition rate increases, and film texture transitions from (1 1 1) to (1 0 0), followed by the formation of large grains with (1 0 0) facets surrounded by clusters of small grains. These changes were observed using electron microscopy, Raman spectroscopy, and X-ray diffraction. To explain our results, we hypothesize that the silicon–plasma interface surrounding the growing diamond seeds acts as a diamond precursor source. Our proposed explanation requires relatively long precursor migration lengths compared to those assumed in standard diamond deposition theory. Finally, we also propose two new mechanisms for diamond precursor adsorption based on well-established physical phenomena and recent publications. Our findings may open new avenues in diamond research, applicable not only to polycrystalline but also to single-crystal diamond deposition
Construction costs and tradeoffs in carnivorous pitcher plant leaves: towards a pitcher leaf economics spectrum
Full text linkBackground:
Leaf economics theory holds that physiological constraints to photosynthesis have a role in the coordinated evolution of multiple leaf traits, an idea that can be extended to carnivorous plants occupying a particular trait space that is constrained by key costs and benefits. Pitcher traps are modified leaves that may face steep photosynthetic costs: a high-volume, three-dimensional tubular structure may be less efficient than a flat lamina. While past research has investigated the photosynthetic costs of pitchers, the exact suite of constraints shaping pitcher trait variation remain under-explored, including constraints to carnivorous function.
Scope:
In this review, we describe various constraints arising from the dual photosynthetic and carnivorous functions of pitchers arising from developmental, functional, budgetary and environmental factors. In addition, we identify the data required to establish the leaf economics spectrum (LES) for carnivorous pitcher plants (CPPs), and – owing to the multifunctional roles of pitcher leaves – discuss difficulties in placing pitchers onto existing frameworks.
Conclusion:
Because pitcher traps serve multiple functions, both photosynthesis and nutrient acquisition (carnivory), they are difficult to place in the context of the LES, especially in light of a current lack of trait data. We describe a spectrum across the independent CPP lineages in approaches to balancing carnivory–photosynthesis tradeoffs. Future efforts to collect relevant data can clarify the forces that shape observed pitcher trait variation, and increase understanding of principles that may be ultimately generalized to other plants
Centered Hardy–Littlewood maximal functions on H-type groups revisited
Full text linkIn this paper, using the method of stationary phase, we obtain the uniform asymptotic behavior of the Poisson kernel, associated to the canonical sub-Laplacian as well as the full Laplacian, on Heisenberg-type groups H (2n,m). We prove that there exists a constant C>0 , independent of (n, m), such that ||M_k||_L^1->L^1,∞ ≤C_n, where is M_k denotes the centered Hardy-Littlewood maximal operator defined by the Korányi norm. While for M=M_cc or M_R, the corresponding operator related to the canonical sub-Riemannian and Riemannian distance respectively, we obtain ||M_k||_L^1->L^1,∞≤ C(3/2)^ m/2 n. In particular, we provide an affirmative answer to the question left open in Li and Qian (Trans Am Math Soc 366:1497–1524, 2014) [22] by means of a much simpler method. Besides, these bounds are perfectly matched with the associated Green function. Furthermore, the (3/2)^ m/2 n order bound remains uniformly valid, whenever the canonical Sub-Riemannian or Riemannian distance are replaced by a large class of Carnot-Carathéodory distances