1,157 research outputs found

    RNA interference knockdown of BRASSINOSTEROID INSENSITIVE1 in maize reveals novel functions for brassinosteroid signaling in controlling plant architecture

    Get PDF
    Brassinosteroids (BRs) are plant hormones involved in various growth and developmental processes. The BR signaling system is well established in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) but poorly understood in maize (Zea mays). BRASSINOSTEROID INSENSITIVE1 (BRI1) is a BR receptor, and database searches and additional genomic sequencing identified five maize homologs including duplicate copies of BRI1 itself. RNA interference (RNAi) using the extracellular coding region of a maize zmbril complementary DNA knocked down the expression of all five homologs. Decreased response to exogenously applied brassinolide and altered BR marker gene expression demonstrate that zmbriI-RNAi transgenic lines have compromised BR signaling. zmbriI-RNAi plants showed dwarf stature due to shortened internodes, with upper internodes most strongly affected. Leaves of zmbriI-RNAi plants are dark green, upright, and twisted, with decreased auricle formation. Kinematic analysis showed that decreased cell division and cell elongation both contributed to the shortened leaves. A BRASSINOSTEROID INSENSITIVE1-ETHYL METHANESULFONATE-SUPPRESSOR1-yellow fluorescent protein (BES1-YFP) transgenic line was developed that showed BR-inducible BES1-YFP accumulation in the nucleus, which was decreased in zmbriI-RNAi. Expression of the BES1-YFP reporter was strong in the auricle region of developing leaves, suggesting that localized BR signaling is involved in promoting auricle development, consistent with the zmbriI-RNAi phenotype. The blade-sheath boundary disruption, shorter ligule, and disrupted auricle morphology of RNAi lines resemble KNOTTED1-LIKE HOMEOBOX (KNOX) mutants, consistent with a mechanistic connection between KNOX genes and BR signaling

    Low-temperature structural model of hcp solid C70_{70}

    Full text link
    We report intermolecular potential-energy calculations for solid C_70{70} and determine the optimum static orientations of the molecules at low temperature; we find them to be consistent with the monoclinic structural model proposed by us in an earlier report [Solid State Commun. {\bf 105), 247 (1998)]. This model indicates that the C_5 axis of the molecule is tilted by an angle \approx18^o from the monoclinic b axis in contrast with the molecular orientation proposed by Verheijen {\it et al.} [J. Chem. Phys. {\bf 166}, 287 (1992)] where the C_5 axis is parallel to the monoclinic b axis. In this calculation we have incorporated the effective bond charge Coulomb potential together with the Lennard-Jones potential between the molecule at the origin of the monoclinic unit cell and its six nearest neighbours, three above and three below. The minimum energy configuration for the molecular orientations turns out to be at θ\theta=18^o, ϕ\phi=8^o, and ψ\psi=5^o, where θ\theta, ϕ\phi, and ψ\psi define the molecular orientations.Comment: ReVTeX (4 pages) + 2 PostScript figure

    Association between weight or Body Mass Index and hand osteoarthritis: a systematic review

    Get PDF
    Objective: To investigate the association between weight or Body Mass Index (BMI) and the development of hand osteoarthritis (OA). Methods: Systematic review of observational studies. Medical databases were searched up to April 2008. Articles which presented data on the association between weight and hand OA were selected. The qualities of these studies were then assessed by two independent reviewers using a 19 criteria scoring syst

    Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

    Get PDF
    The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

    Maternal Near Miss and Mortality in a Rural Referral Hospital in Northern Tanzania: A Cross-Sectional Study.

    Get PDF
    Maternal morbidity and mortality in sub-Saharan Africa remains high despite global efforts to reduce it. In order to lower maternal morbidity and mortality in the immediate term, reduction of delay in the provision of quality obstetric care is of prime importance. The aim of this study is to assess the occurrence of severe maternal morbidity and mortality in a rural referral hospital in Tanzania as proposed by the WHO near miss approach and to assess implementation levels of key evidence-based interventions in women experiencing severe maternal morbidity and mortality. A prospective cross-sectional study was performed from November 2009 until November 2011 in a rural referral hospital in Tanzania. All maternal near misses and maternal deaths were included. As not all WHO near miss criteria were applicable, a modification was used to identify cases. Data were collected from medical records using a structured data abstraction form. Descriptive frequencies were calculated for demographic and clinical variables, outcome indicators, underlying causes, and process indicators. In the two-year period there were 216 maternal near misses and 32 maternal deaths. The hospital-based maternal mortality ratio was 350 maternal deaths per 100,000 live births (95% CI 243-488). The maternal near miss incidence ratio was 23.6 per 1,000 live births, with an overall case fatality rate of 12.9%. Oxytocin for prevention of postpartum haemorrhage was used in 96 of 201 women and oxytocin for treatment of postpartum haemorrhage was used in 38 of 66 women. Furthermore, eclampsia was treated with magnesium sulphate in 87% of all cases. Seventy-four women underwent caesarean section, of which 25 women did not receive prophylactic antibiotics. Twenty-eight of 30 women who were admitted with sepsis received parenteral antibiotics. The majority of the cases with uterine rupture (62%) occurred in the hospital. Maternal morbidity and mortality remain challenging problems in a rural referral hospital in Tanzania. Key evidence-based interventions are not implemented in women with severe maternal morbidity and mortality. Progress can be made through up scaling the use of evidence-based interventions, such as the use of oxytocin for prevention and treatment of postpartum haemorrhage

    Response-Time Analysis for Non-Preemptive Global Scheduling with {FIFO} Spin Locks

    Get PDF
    Motivated by the lack of response-time analyses for non-preemptive global scheduling that consider shared resources, this paper provides such an analysis for global job-level fixed-priority (JLFP) scheduling policies and FIFO-ordered spin locks. The proposed analysis computes response-time bounds for a set of resource-sharing jobs subject to release jitter and execution-time uncertainties by implicitly exploring all possible execution scenarios using state-abstraction and state-pruning techniques. A large-scale empirical evaluation of the proposed analysis shows it to be substantially less pessimistic than simple execution-time inflation methods, thanks to the explicit modeling of contention for shared resources and scenario-aware blocking analysis

    Novel spectrometer designs for laser-driven ion acceleration

    Get PDF
    We propose novel spectrometer designs that aim to enhance the measured spectral range of ions on a finite-sized detector. In contrast to the traditional devices that use a uniform magnetic field, in which the deflection of particles increases inversely proportional to their momentum, in a gradient magnetic field, the deflection of particles will decrease due to the reduction of the magnetic field along their propagation. In this way, low-energy ions can reach the detector because they are deflected less, compared to the uniform field case. By utilizing a gradient magnetic field, the non-linear dispersion of ions in a homogeneous magnetic field approaches nearly linear dispersion behavior. Nonetheless, the dispersion of low-energy ions, using a dipole field, remains unnecessarily high. In this article, we discuss the employed methodology and present simulation results of the spectrometer with an extended ion spectral range, focusing on the minimum detectable energy (energy dynamic range) and energy resolution

    Contralateral hip fractures and other osteoporosis-related fractures in hip fracture patients: Incidence and risk factors. An observational cohort study of 1,229 patients

    Get PDF
    Purpose: To report risk factors, 1-year and overall risk for a contralateral hip and other osteoporosis-related fractures in a hip fracture population. Methods: An observational study on 1,229 consecutive patients of 50 years and older, who sustained a hip fracture between January 2005 and June 2009. Fractures were scored retrospectively for 2005-2008 and prospectively for 2008-2009. Rates of a contralateral hip and other osteoporosis- related fractures were compared between patients with and without a history of a fracture. Previous fractures, gender, age and ASA classification were analysed as possible risk factors. Results: The absolute risk for a contralateral hip fracture was 13.8 %, for one or more osteoporosis-related fracture( s) 28.6 %. First-, second- and third-year risk for a second hip fracture was 2, 1 and 0 %. Median (IQR) interval between both hip fractures was 18.5 (26.6) months. One-year incidence of other fractures was 6 %. Only age was a risk factor for a contralateral hip fracture, hazard ratio (HR) 1.02 (1.006-1.042, p = 0.008). Patients with a history of a fracture (33.1 %) did not have a higher incidence of fractures during follow-up (16.7 %) than patients without fractures in their history (14 %). HR for a contralateral hip fracture for the fracture versus the non-fracture group was 1.29 (0.75-2.23, p = 0.360). Conclusion: The absolute risk of a contralateral hip fracture after a hip fracture is 13.8 %, the 1-year risk was 2 %, with a short interval between the 2 hip fractures. Age was a risk factor for sustaining a contralateral hip fracture; a fracture in history was not
    corecore