Effects of exogenous spermidine on photosynthesis, xanthophyll cycle and endogenous polyamines in cucumber seedlings exposed to salinity

The effects of exogenous spermidine (Spd, 1 mmol·L-1) on photosynthetic characteristics, xanthophylls cycle components and endogenous polyamines levels were investigated in cucumber seedlings subjected to salt stress (75 mmol·L-1 NaCl). Chlorophyll contents and net photosynthetic rate (PN) of cucumber seedlings showed a significant decrease under salinity but an increase with exogenous Spd application. Salt stress caused a remarkable decline in the maximum quantum efficiency (Fv/Fm) and the actual efficiency of photosystem II (ФPSⅡ), where an increase was observed in the constitutive loss processes (ΦNO). Application of exogenous Spd significantly decreased ФNO and enhanced regulated non-photochemical energy loss (ФNPQ) in the salt-stressed plants. Spd treatment caused an increase in the size of xanthophyll cycle pool (VAZ) and further enhanced de-epoxidation of the xanthophyll cycle (DEPS) under salt stress. These results suggest that exogenous Spd alleviated salt-mediated decline in photosynthetic efficiency through the enhanced involvement of the energy dissipation that is dependent on the xanthophyll cycle. In addition, foliar spray Spd significantly increased the free, bound and conjugated polyamines in the leaves of the salt stressed plants. Spd also increased the free putrescine (Put)/(Spd+Spm) ratio and decreased bound and conjugated Put/(Spd+Spm) under salinity. Thus, we conclude that Spd can alleviate salt-induced damage on cucumber seedlings by regulating the levels of endogenous polyamines, which was associated with an improvement in the photochemical efficiency of PSII of the salt stressed plants.Key words: Cucumber, endogenous polyamines, photosynthetic characteristics, salt stress, spermidine

Cerebellar defects in Pdss2 conditional knockout mice during embryonic development and in adulthood

PDSS2 is a gene that encodes one of the two subunits of trans-prenyl diphosphate synthase that is essential for ubiquinone biosynthesis. It is known that mutations in PDSS2 can cause primary ubiquinone deficiency in humans and a similar disease in mice. Cerebellum is the most often affected organ in ubiquinone deficiency, and cerebellar atrophy has been diagnosed in many infants with this disease. In this study, two Pdss2 conditional knockout mouse lines directed by Pax2-cre and Pcp2-cre were generated to investigate the effect of ubiquinone deficiency on cerebellum during embryonic development and in adulthood, respectively. The Pdss2 f/-; Pax2-cre mouse recapitulates some symptoms of ubiquinone deficiency in infants, including severe cerebellum hypoplasia and lipid accumulation in skeletal muscles at birth. During early cerebellum development (E12.5-14.5), Pdss2 knockout initially causes the delay of radial glial cell growth and neuron progenitor migration, so the growth of mutant cerebellum is retarded. During later development (E15.5-P0), increased ectopic apoptosis of neuroblasts and impaired cell proliferation result in the progression of cerebellum hypoplasia in the mutant. Thus, the mutant cerebellum contains fewer neurons at birth, and the cells are disorganized. The developmental defect of mutant cerebellum does not result from reduced Fgf8 expression before E12.5. Electron microscopy reveals mitochondrial defects and increased autophagic-like vacuolization that may arise in response to abnormal mitochondria in the mutant cerebellum. Nevertheless, the mutant mice die soon after birth probably due to cleft palate and micrognathia, which may result from Pdss2 knockout caused by ectopic Pax2-cre expression in the first branchial arch. On the other hand, the Pdss2 f/-; Pcp2-cre mouse is healthy at birth but gradually loses cerebellar Purkinje cells and develops ataxia-like symptoms at 9.5months; thus this conditional knockout mouse may serve as a model for ubiquinone deficiency in adult patients. In conclusion, this study provides two mouse models of Pdss2 based ubiquinone deficiency. During cerebellum development, Pdss2 knockout results in severe cerebellum hypoplasia by impairing cell migration and eliciting ectopic apoptosis, whereas Pdss2 knockout in Purkinje cells at postnatal stages leads to the development of cerebellar ataxia. © 2011 Elsevier Inc.postprin

The Outstanding Decisions of the United States Supreme Court in 1954

We perform a kinematic and morphological analysis of 44 star-forming galaxies at z ̃ 2 in the COSMOS legacy field using near-infrared spectroscopy from Keck/MOSFIRE and F160W imaging from CANDELS/3D-HST as part of the ZFIRE survey. Our sample consists of cluster and field galaxies from 2.0 < z < 2.5 with K-band multi-object slit spectroscopic measurements of their Hα emission lines. Hα rotational velocities and gas velocity dispersions are measured using the Heidelberg Emission Line Algorithm (HELA), which compares directly to simulated 3D data cubes. Using a suite of simulated emission lines, we determine that HELA reliably recovers input S 0.5 and angular momentum at small offsets, but V 2.2/σ g values are offset and highly scattered. We examine the role of regular and irregular morphology in the stellar mass kinematic scaling relations, deriving the kinematic measurement S 0.5, and finding {log}({S}0.5)=(0.38+/- 0.07){log}(M/{M}☉ -10)+(2.04+/- 0.03) with no significant offset between morphological populations and similar levels of scatter (̃0.16 dex). Additionally, we identify a correlation between M ⋆ and V 2.2/σ g for the total sample, showing an increasing level of rotation dominance with increasing M ⋆, and a high level of scatter for both regular and irregular galaxies. We estimate the specific angular momenta (j disk) of these galaxies and find a slope of 0.36 ± 0.12, shallower than predicted without mass-dependent disk growth, but this result is possibly due to measurement uncertainty at M ⋆ < 9.5 However, through a Kolmogorov-Smirnov test we find irregular galaxies to have marginally higher j disk values than regular galaxies, and high scatter at low masses in both populations

Web-flange distortional buckling of partially restrained cold-formed steel purlins under uplift loading

It is well-known that cold-formed steel (CFS) members of open section can buckle locally, distortionally and/or lateral-torsionally. Since they are usually used as the secondary structural members in buildings to support roof and side cladding or sheeting, CFS beams are mostly treated as the restrained beams either fully or partially in its lateral and/or rotational directions. For a thin-walled channel- or zed-section beam subjected to uplift loading, if its upper flange is fully restrained in its lateral and rotational directions, the beam will not buckle lateral-torsionally, but may have a web-flange distortional buckling. In the literature there is limited information on the web-flange distortional buckling and currently the critical stress for the web-flange distortional buckling is calculated mainly by using numerical methods. In this paper an analytical model is presented to describe the web-flange distortional buckling behavior of the partially restrained CFS beams when subjected to uplift loading. Formula used to calculate the critical stress of web-flange distortional buckling is derived. Comparisons of the predicted critical stresses with those obtained using finite strip and finite element methods are provided to demonstrate the appropriateness of the model proposed

Beyond First/Last Mile Active Transportation - BikeShare@UH

Bike sharing is a new green transportation solution that has been developed and adopted at various cities around the world. In this paper, we present the process and results of the design and prototypes that a group of undergraduate students developed for a BikeShare@UH program during Summer 2017. After presenting the detailed results of four project teams focusing on customer discovery, bike share station (BSS) location identification, cloud-based mobile computing platform for user engagement and bike share program operation and management, smart lock, and alternative energy source based on PV panel. With the phase one implementation at the University planned in Spring 2018, we anticipate gathering real time data and feedback to improve the system.Cockrell School of Engineerin

Heat transfer analysis in multi-layered materials with interfacial thermal resistance

Interfacial thermal resistance (ITR) presents a measure of the thermal resistance to heat transport caused by the interface in composites to a thermal movement when the heat flows across it. In the heat transfer analysis, the presence of an ITR invalidates the continuity condition of temperature at the interface, so that a special treatment is required. In this paper, two one-dimensional models are developed for the heat transfer analysis in multi-layered materials with ITR. One is to create a virtual layer at the interface to represent the ITR and the other is to use a local artificial layer surrounding the interface with modified thermal properties to reflect the influence of ITR on the heat transfer in the layer involving the interface. As the application of the present models, numerical examples are also provided for the heat transfer analysis of a multi-layered composite and a substrate with multilayer surface coatings, from which the effect of ITR on the heat transfer in composite materials is demonstrated

Internal gamma gamma-opacity in Active Galactic Nuclei and the consequences for the TeV observations of M87 and Cen A

Low Luminosity Active Galactic Nuclei (LLAGNs) possess the characteristic features of more luminous Active Galactic Nuclei (AGNs) but exhibit a much lower nuclear Halpha luminosity than their more luminous counterparts. M87 (NGC 4486) and Centaurus A (NGC 5128, CenA) are well-studied nearby LLAGNs. As an additional feature they show gamma-radiation up to TeV (10^{12}eV) energies, but the origin of this radiation is not resolved. The coincident observation of a radio and TeV flare in M87 suggests that the TeV radiation is produced within around 50-100 gravitational radii of the central supermassive black hole, depending on the assumed value of the mass of the black hole. Strong radiation fields can be produced in the central region of an (LL)AGN, e.g., by the accretion flow around the black hole, the jet plasma, or stars closely orbiting the black hole. These radiation fields can lead to the absorption of emitted TeV photons, and in fact high optical depths of such fields can make TeV detection from inner regions impossible. In this paper we consider the accretion flow around the black hole as the most prominent source for such a radiation field and we accordingly calculate the probability for absorption of TeV photons produced near the black holes in M87 and CenA assuming a low luminosity Shakura-Sunyaev Disk (SSD). We find that the results are very different for between the two LLAGNs. While the inner region of M87 is transparent for TeV radiation up to 15TeV, the optical depth in CenA is >> 1, leading to an absorption of TeV photons that might be produced near the central black hole. These results imply either that the TeV gamma production sites and processes are different for both sources, or that LLAGN black holes do not accrete (at least only) in form of a low luminosity SSD.Comment: accepted for publication in Ap

Imaging the Black Hole Silhouette of M87: Implications for Jet Formation and Black Hole Spin

The silhouette cast by the horizon of the supermassive black hole in M87 can now be resolved with the emerging millimeter very-long baseline interferometry (VLBI) capability. Despite being ~2000 times farther away than SgrA* (the supermassive black hole at the center of the Milky-Way and the primary target for horizon-scale imaging), M87's much larger black hole mass results in a horizon angular scale roughly half that of SgrA*'s, providing another practical target for direct imaging. However, unlike SgrA*, M87 exhibits a powerful radio jet, providing an opportunity to study jet formation physics on horizon scales. We employ a simple, qualitatively correct force-free jet model to explore the expected high-resolution images of M87 at wavelengths of 1.3mm and 0.87mm (230GHz and 345GHz), for a variety of jet parameters. We show that future VLBI data will be able to constrain the size of the jet footprint, the jet collimation rate, and the black hole spin. Polarization will further probe the structure of the jet's magnetic field and its effect on the emitting gas. Horizon-scale imaging of M87 and SgrA* will enable for the first time the empirical exploration of the relationship between the mass and spin of a black hole and the characteristics of the gas inflow/outflow around it.Comment: 18 pages, 7 figures, accepted by Ap

A generic decision model for developing concentrated rural settlement in post-disaster reconstruction : a China study

2013-2014 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Supporting people with type 2 diabetes diabetes in effective use of their medicine through mobile health technology integrated with clinical care (SuMMiT-D pilot): results of a feasibility randomised trial

Background:The purpose of this 6-month intervention pilot feasibility randomised trial was to test sending brief messages using mobile phones to promote self-management through taking medication as prescribed to people with type 2 diabetes. This was to inform the design and conduct of a future large-scale United Kingdom based clinical trial and establish feasibility of recruitment, the technology used, follow up, and data collection. Methods: A multicentre individually randomised, controlled parallel group trial in primary care, recruiting adults (≥35 years) with type 2 diabetes in England. Consenting participants were randomly allocated to receive short message system text-messages up to four times a week, or usual care, for a period of six months; messages contained behavioural change techniques targeting medication use. The primary outcome was the rate of recruitment to randomisation of participants to the trial with a planned rate of 22 participants randomised per month. The study also aimed to establish feasibility of follow up at 6-months, with an aim of retaining more than 80% of participants. Data, including patient reported measures, were collected at baseline and the end of the 6-month follow-up period, and a notes review was completed at 24 months. Results: The trial took place between 26 November 2018 and 30 September 2019. In total 209 participants were randomly allocated to intervention (n=103) or usual care (n=106). The maximum rate of monthly recruitment to the trial was 60-80 participants per month. In total, 12,734 messages were sent to participants. Of these messages, 47 were identified as having failed to be sent by the service provider. Participants sent 2,864 messages to the automated messaging system. Baseline data from medical records were available for >90% of participants with the exception of cholesterol (78.9%). At six months, a further HbA1c measurement was reported for 67% of participants. In total medical record data were available at six-months for 207 (99.0%) of participants and completed self-report data were available for 177 (84.7%) of participants. Conclusion: The feasibility of a large-scale randomised evaluation of brief message intervention for people with type 2 diabetes appears to be high using this efficient design. Failure rate of sending messages is low, rapid recruitment was achieved among people with type 2 diabetes, clinical data is available on participants from routine medical records and self-report of economic measures was acceptable