University of North Texas

About: University of North Texas is a education organization based out in Denton, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 11866 authors who have published 26984 publications receiving 705376 citations. The organization is also known as: Fight, North Texas & UNT.

Jasmonic Acid Is Required for Plant Acclimation to a Combination of High Light and Heat Stress

Abstract: In the field, plants experience high light (HL) intensities that are often accompanied by elevated temperatures. Such conditions are a serious threat to agriculture production, because photosynthesis is highly sensitive to both HL intensities and high-temperature stress. One of the potential cellular targets of HL and heat stress (HS) combination is PSII because its degree of photoinhibition depends on the balance between the rate of PSII damage (induced by light stress), and the rate of PSII repair (impaired under HS). Here, we studied the responses of Arabidopsis (Arabidopsis thaliana) plants to a combination of HL and HS (HL+HS) conditions. Combined HL+HS was accompanied by irreversible damage to PSII, decreased D1 (PsbA) protein levels, and an enhanced transcriptional response indicative of PSII repair activation. We further identified several unique aspects of this stress combination that included enhanced accumulation of jasmonic acid (JA) and JA-Ile, elevated expression of over 2,200 different transcripts that are unique to the stress combination (including many that are JA-associated), and distinctive structural changes to chloroplasts. A mutant deficient in JA biosynthesis (allene oxide synthase) displayed enhanced sensitivity to combined HL+HS and further analysis revealed that JA is required for regulating several transcriptional responses unique to the stress combination. Our study reveals that JA plays an important role in the acclimation of plants to a combination of HL+HS.

The role of glia, mitochondria, and the immune system in glaucoma.

Abstract: Author(s): Tezel, Gulgun; Fourth ARVO/Pfizer Ophthalmics Research Institute Conference Working Group

Traits of Effective Teachers

Abstract: (2006). Traits of Effective Teachers. Arts Education Policy Review: Vol. 107, No. 4, pp. 23-29.

Synthesis, mechanistic investigation, and application of photoluminescent sulfur and nitrogen co-doped carbon dots

Abstract: Heteroatom doped carbon dots (CDs) with consummate photoluminescence quantum yield (PLQY) are of great interest in various applications such as trace element detection, biomolecule markers, and chemical sensing. However, due to the low doping efficiency of the reaction, a high precursor ratio is routinely used to obtain CDs with considerable photoluminescence quantum yield (PLQY). In this contribution, we report a single-step hydrothermal method having the highest doping efficiency to synthesize sulfur and nitrogen co-doped semi-crystalline carbon dots (S,N-CDs) with superior quantum yield (QY). Here, the unprecedented doping efficiency of the reaction enables an order of magnitude reduction in the starting precursor ratio, in comparison with previous reports. Moreover, for the first time, complementary theoretical and comprehensive spectroscopic techniques were employed to derive deep insight into the photoluminescence mechanism and the shifting of specific energy levels in doped CDs was identified as the reason behind the enhanced photoluminescence of doped CDs. The PLQY and luminescent characteristics of the S,N-CDs can be tuned by controlling the precursor molar ratio, the extent of surface oxidation, and chemical status of S in the CDs. While most methods report high PLQY for amorphous CDs, our technique produces semi-crystalline CDs with more than 55% QY. Another unique attribute of the S,N-CDs is the high monodispersity and defined surface chemistry and the resultant highly robust excitation-independent luminescence that is stable over a broad range of pH values and in an extremely reactive environment. The detailed structural and chemical investigations using spectroscopic and microscopic techniques combining molecular simulation revealed that the superior PLQY and luminescence of S,N-CDs are due to the heteroatom directed, oxidized carbon-based surface passivation. The remarkable, robust fluorescence properties of S,N-CDs were applied for the ultra-trace detection of Hg2+ with a detection limit of 100 pM. The novel insights into the photoluminescence of doped CDs, the robust luminescence, and enhanced doping reaction efficiency reported here are envisaged to drive transformative changes in the design of CDs with peerless properties for futuristic applications.