Note on a new fundamental length scale ll instead of the Newtonian constant GG

The newly proposed entropic gravity suggests gravity as an emergent force rather than a fundamental one. In this approach, the Newtonian constant $G$ does not play a fundamental role any more, and a new fundamental constant is required to replace its position. This request also arises from some philosophical considerations to contemplate the physical foundations for the unification of theories. We here consider the suggestion to derive $G$ from more fundamental quantities in the presence of a new fundamental length scale $l$, which is suspected to originate from the structure of quantum space-time, and can be measured directly from Lorentz-violating observations. Our results are relevant to the fundamental understanding of physics, and more practically, of natural units, as well as explanations of experimental constraints in searching for Lorentz violation.Comment: 10 latex pages, final version for journal publicatio

Preparation of (Lu,Y)3(Al,Sc,Cr)2Al3O12 phosphor ceramics with high thermal stability for near-infrared LED/LD

Near-infrared (NIR) phosphor-converted light-emitting diodes/laser diodes (LEDs/LDs) are prospective lighting sources for NIR spectroscopy. However, developing NIR phosphor materials with desired thermal robustness and high photoelectric efficiency is a crucial challenge for their applications. In this work, based on the cationic radius matching effect, a series of (Lu,Y)3(Al,Sc,Cr)2Al3O12 NIR phosphor ceramics (LuYScCr NIR-PCs) were fabricated by vacuum sintering. Excellent thermal stability (95%@150 ℃) was obtained in the prepared NIR-PCs, owing to their weak electron–phonon coupling effect (small Huang–Rhys factor). Being excited at 460 nm, NIR-PCs realized a broadband emission (650–850 nm) with internal quantum efficiency (IQE) of 60.68%. Combining NIR-PCs with LED/LD chips, the maximum output power of the encapsulated LED prototype was 447 mW@300 mA with photoelectric efficiency of as high as 18.6 %@180 mA, and the maximum output power of the LD prototype was 814 [email protected] A. The working temperatures of NIR-PCs were 70.8 ℃@300 mA (LED) and 102.8 ℃@3 A (LD). Finally, the prepared NIR-PCs applied in food detection were verified in this study, demonstrating their anticipated application prospects in the future

Hydrogen Peroxide Acts on Sensitive Mitochondrial Proteins to Induce Death of a Fungal Pathogen Revealed by Proteomic Analysis

How the host cells of plants and animals protect themselves against fungal invasion is a biologically interesting and economically important problem. Here we investigate the mechanistic process that leads to death of Penicillium expansum, a widespread phytopathogenic fungus, by identifying the cellular compounds affected by hydrogen peroxide (H2O2) that is frequently produced as a response of the host cells. We show that plasma membrane damage was not the main reason for H2O2-induced death of the fungal pathogen. Proteomic analysis of the changes of total cellular proteins in P. expansum showed that a large proportion of the differentially expressed proteins appeared to be of mitochondrial origin, implying that mitochondria may be involved in this process. We then performed mitochondrial sub-proteomic analysis to seek the H2O2-sensitive proteins in P. expansum. A set of mitochondrial proteins were identified, including respiratory chain complexes I and III, F1F0 ATP synthase, and mitochondrial phosphate carrier protein. The functions of several proteins were further investigated to determine their effects on the H2O2-induced fungal death. Through fluorescent co-localization and the use of specific inhibitor, we provide evidence that complex III of the mitochondrial respiratory chain contributes to ROS generation in fungal mitochondria under H2O2 stress. The undesirable accumulation of ROS caused oxidative damage of mitochondrial proteins and led to the collapse of mitochondrial membrane potential. Meanwhile, we demonstrate that ATP synthase is involved in the response of fungal pathogen to oxidative stress, because inhibition of ATP synthase by oligomycin decreases survival. Our data suggest that mitochondrial impairment due to functional alteration of oxidative stress-sensitive proteins is associated with fungal death caused by H2O2

Use of a Generalized Additive Model to Investigate Key Abiotic Factors Affecting Microcystin Cellular Quotas in Heavy Bloom Areas of Lake Taihu

Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation

The influence of macrophytes on sediment resuspension and the effect of associated nutrients in a shallow and large lake (Lake Taihu, China)

A yearlong campaign to examine sediment resuspension was conducted in large, shallow and eutrophic Lake Taihu, China, to investigate the influence of vegetation on sediment resuspension and its nutrient effects. The study was conducted at 6 sites located in both phytoplankton-dominated zone and macrophyte-dominated zone of the lake, lasting for a total of 13 months, with collections made at two-week intervals. Sediment resuspension in Taihu, with a two-week high average rate of 1771 g.m(-2).d(-1) and a yearly average rate of 377 g.m(-2).d(-1), is much stronger than in many other lakes worldwide, as Taihu is quite shallow and contains a long fetch. The occurrence of macrophytes, however, provided quite strong abatement of sediment resuspension, which may reduce the sediment resuspension rate up to 29-fold. The contribution of nitrogen and phosphorus to the water column from sediment resuspension was estimated as 0.34 mg.L-1 and 0.051 mg.L-1 in the phytoplankton-dominated zone. Sediment resuspension also largely reduced transparency and then stimulated phytoplankton growth. Therefore, sediment resuspension may be one of the most important factors delaying the recovery of eutrophic Lake Taihu, and the influence of sediment resuspension on water quality must also be taken into account by the lake managers when they determine the restoration target.Peer reviewe

Efficacy of ABA-Mimicking Ligands in Controlling Water Loss and Maintaining Antioxidative Capacity of Spinacia oleracea

Abscisic acid (ABA) is a central regulator for various developmental processes and responses to abiotic stresses in plants. However, its practical application in controlling water loss of postharvest produces is largely restrained. Herein, the present study reported that two ABA-mimicking ligands, AM1 and AMF4, markedly reduced water loss by promoting stomatal closure and effectively alleviated weight loss in spinach. AM1 and AMF4 also alleviated chlorophyll and vitamin C degradation and simultaneously reduced hydrogen peroxide and malondialdehyde (MDA) production; moreover, both enzymatic and nonenzymatic systems involved in antioxidative capacity were activated. The expression levels of SoOST1, SoSLAC1, SoRCAR3, SoPYLS, SoNCED3, and SoAREB1 were also up-regulated. These findings indicate that AM1 and AMF4 are promising as novel means for reducing water loss, maintaining visual quality, delaying senescence, and extending shelf life in leafy vegetables

Honokiol suppresses mycelial growth and reduces virulence of Botrytis cinerea by inducing autophagic activities and apoptosis

Fungal pathogens lead to severe quality deterioration and yield loss, making it urgent to explore efficient measures to control fungal diseases at the preharvest and postharvest stages of plants. Therefore, studies on natural substances targeting alternative antimicrobial targets have become hot spots of research. Here, we show that honokiol, a polyphenolic compound obtained from Magnolia officinalis, significantly suppressed mycelial growth and reduced virulence of B. cinerea on harvested fruit by inducing autophagic activities and apoptosis. Moreover, honokiol was capable of abolishing the mitochondrial membrane potential and inducing the accumulation of reactive oxygen species. Some key genes involved in pathogenicity on fruit were also found significantly down-regulated. In summary, honokiol was effective as an alternative agent targeting autophagic and apoptotic machineries to control the incidence of gray mold, which may further enrich the toolkit of crop managers for fighting postharvest diseases caused by this and similar fungi