1,653 research outputs found
Chemical composition and toxic activity of essential oil of Caryopteris incana against Sitophilus zeamais
During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Caryopteris incana aerial parts was found to possess strong insecticidal activities against the maize weevil, Sitophilus zeamais. A total of 37 components of the essential oil were identified by GC and GC/MS. Estragole (24.8%) and linalool (14.0%) are the two main components of the essential oil followed by 1,8-cineol (5.2%) and δ-guaiene (4.1%). The essential oil possesses strong fumigant toxicity against S. zeamais adults with an LC50 value of 10.05 mg/L air. The essential oil of C. incana also showed contact toxicity against S. zeamais adults with an LD50 value of 122.65 μg/adult. The essential oil C. incana may have potential to be developed as a new natural fumigant/insecticide for the control of stored product insects.Key words: Caryopteris incana, Sitophilus zeamais, fumigant, contact toxicity, essential oil composition, estragole, linalool
Shocks and Universal Statistics in (1+1)-Dimensional Relativistic Turbulence
We propose that statistical averages in relativistic turbulence exhibit
universal properties. We consider analytically the velocity and temperature
differences structure functions in the (1+1)-dimensional relativistic
turbulence in which shock waves provide the main contribution to the structure
functions in the inertial range. We study shock scattering, demonstrate the
stability of the shock waves, and calculate the anomalous exponents. We comment
on the possibility of finite time blowup singularities.Comment: 37 pages, 7 figure
Intertwining Operator Realization of the AdS/CFT Correspondence
We give a group-theoretic interpretation of the AdS/CFT correspondence as
relation of representation equivalence between representations of the conformal
group describing the bulk AdS fields and the coupled boundary fields
and . We use two kinds of equivalences. The first kind is
equivalence between bulk fields and boundary fields and is established here.
The second kind is the equivalence between coupled boundary fields. Operators
realizing the first kind of equivalence for special cases were given by Witten
and others - here they are constructed in a more general setting from the
requirement that they are intertwining operators. The intertwining operators
realizing the second kind of equivalence are provided by the standard conformal
two-point functions. Using both equivalences we find that the bulk field has in
fact two boundary fields, namely, the coupled boundary fields. Thus, from the
viewpoint of the bulk-boundary correspondence the coupled fields are on an
equal footing. Our setting is more general since our bulk fields are described
by representations of the Euclidean conformal group , induced from
representations of the maximal compact subgroup of . From
these large reducible representations we can single out representations which
are equivalent to conformal boundary representations labelled by the conformal
weight and by arbitrary representations of the Euclidean Lorentz group
, such that is contained in the restriction of to .
Thus, our boundary-to-bulk operators can be compared with those in the
literature only when for a fixed we consider a 'minimal' representation
containing .Comment: 25 pages, TEX file using harvmac.tex; v2: misprints corrected; to
appear in Nuclear Physics
Gluon Scattering Amplitudes in Finite Temperature Gauge/Gravity Dualities
We examine the gluon scattering amplitude in N=4 super Yang-Mills at finite
temperature with nonzero R-charge densities, and in Non-Commutative gauge
theory at finite temperature. The gluon scattering amplitude is defined as a
light-like Wilson loop which lives at the horizon of the T-dual black holes of
the backgrounds we consider. We study in detail a special amplitude, which
corresponds to forward scattering of a low energy gluon off a high energy one.
For this kinematic configuration in the considered backgrounds, we find the
corresponding minimal surface which is directly related to the gluon scattering
amplitude. We find that for increasing the chemical potential or the
non-commutative parameter, the on-shell action corresponding to our Wilson loop
in the T-dual space decreases. For all of our solutions the length of the short
side of the Wilson loop is constrained by an upper bound which depends on the
temperature, the R-charge density and the non-commutative parameter. Due to
this constraint, in the limit of zeroth temperature our approach breaks down
since the upper bound goes to zero, while by keeping the temperature finite and
letting the chemical potential or the non-commutative parameter to approach to
zero the limit is smooth.Comment: 30 pages, 16 figures, minor corrections (plus improved numerical
computation for the non-commutative case
Young Women With Type 1 Diabetes Have Lower Bone Mineral Density That Persists Over Time
OBJECTIVE—Individuals with type 1 diabetes have decreased bone mineral density (BMD), yet the natural history and pathogenesis of osteopenia are unclear. We have previously shown that women with type 1 diabetes (aged 13–35 years) have lower BMD than community age-matched nondiabetic control subjects. We here report 2-year follow-up BMD data in this cohort to determine the natural history of BMD in young women with and without diabetes
Cronobacter sakazakii clinical isolates overcome host barriers and evade the immune response
Cronobacter sakazakii is the most frequently clinically isolated species of the Cronobacter genus. However the virulence factors of C. sakazakii including their ability to overcome host barriers remains poorly studied. In this study, ten clinical isolates of C. sakazakii were assessed for their ability to invade and translocate through human microvascular endothelial cells (HBMEC). Their ability to avoid phagocytosis in human macrophages U937 and human brain microglial cells was investigated. Additionally, they were tested for serum sensitivity and the presence of the Cronobacter plasminogen activation gene (cpa) gene, which is reported to confer serum resistance. Our data showed that the clinical C. sakazakii strains invaded and translocated through Caco-2 and HBMEC cell lines and some strains showed significantly higher levels of invasion and translocation. Moreover, C. sakazakii was able to persist and even multiply in phagocytic macrophage and microglial cells. All strains, except one, were able to withstand human serum exposure, the single serum sensitive strain was also the only one which did not encode for the cpa gene. These results demonstrate that C. sakazakii clinical host immune response indicating their capacity to cause diseases such as necrotizing enterocolitis (NEC) and meningitis. Our data showed for the first time the ability of C. sakazakii clinical isolates to survive and multiply within human microglial cells. Additionally, it was shown that C. sakazakii clinical strains have the capacity to translocate through the Caco-2 and HBMEC cell lines paracellularly
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Cannabis sativa and the endogenous cannabinoid system: therapeutic potential for appetite regulation
The herb Cannabis sativa (C. sativa) has been used in China and on the Indian subcontinent for thousands of years as a medicine. However, since it was brought to the UK and then the rest of the western world in the late 19th century, its use has been a source of controversy. Indeed, its psychotropic side effects are well reported but only relatively recently has scientific endeavour begun to find valuable uses for either the whole plant or its individual components. Here, we discuss evidence describing the endocannabinoid system, its endogenous and exogenous ligands and their varied effects on feeding cycles and meal patterns. Furthermore we also critically consider the mounting evidence which suggests non‐tetrahydrocannabinol phytocannabinoids play a vital role in C. sativa‐induced feeding pattern changes. Indeed, given the wide range of phytocannabinoids present in C. sativa and their equally wide range of intra‐, inter‐ and extra‐cellular mechanisms of action, we demonstrate that non‐Δ9tetrahydrocannabinol phytocannabinoids retain an important and, as yet, untapped clinical potential
Arachidonic acid inhibition of L-type calcium (CaV1.3b) channels varies with accessory CaVβ subunits
Arachidonic acid (AA) inhibits the activity of several different voltage-gated Ca2+ channels by an unknown mechanism at an unknown site. The Ca2+ channel pore-forming subunit (CaVα1) is a candidate for the site of AA inhibition because T-type Ca2+ channels, which do not require accessory subunits for expression, are inhibited by AA. Here, we report the unanticipated role of accessory CaVβ subunits on the inhibition of CaV1.3b L-type (L-) current by AA. Whole cell Ba2+ currents were measured from recombinant channels expressed in human embryonic kidney 293 cells at a test potential of −10 mV from a holding potential of −90 mV. A one-minute exposure to 10 µM AA inhibited currents with β1b, β3, or β4 58, 51, or 44%, respectively, but with β2a only 31%. At a more depolarized holding potential of −60 mV, currents were inhibited to a lesser degree. These data are best explained by a simple model where AA stabilizes CaV1.3b in a deep closed-channel conformation, resulting in current inhibition. Consistent with this hypothesis, inhibition by AA occurred in the absence of test pulses, indicating that channels do not need to open to become inhibited. AA had no effect on the voltage dependence of holding potential–dependent inactivation or on recovery from inactivation regardless of CaVβ subunit. Unexpectedly, kinetic analysis revealed evidence for two populations of L-channels that exhibit willing and reluctant gating previously described for CaV2 channels. AA preferentially inhibited reluctant gating channels, revealing the accelerated kinetics of willing channels. Additionally, we discovered that the palmitoyl groups of β2a interfere with inhibition by AA. Our novel findings that the CaVβ subunit alters kinetic changes and magnitude of inhibition by AA suggest that CaVβ expression may regulate how AA modulates Ca2+-dependent processes that rely on L-channels, such as gene expression, enzyme activation, secretion, and membrane excitability
Folate Status of Reproductive Age Women and Neural Tube Defect Risk: The Effect of Long-Term Folic Acid Supplementation at Doses of 140 µg and 400 µg per Day
Primary prevention of most folate-responsive neural tube defects (NTDs) may not require 400 μg folic acid/day but may be achieved by attaining a high maternal folate status. Using RBC folate ≥906 nmol/L as a marker for NTD risk reduction, the study aimed to determine the change in blood folate concentrations in reproductive age women in response to long-term folic acid supplementation at 400 µg/day and 140 µg/day (dose designed to mimic the average daily folic acid intake received from New Zealand’s proposed mandatory bread fortification program). Participants were randomly assigned to a daily folic acid supplement of 140 µg (n = 49), 400 µg (n = 48) or placebo (n = 47) for 40 weeks. RBC folate concentrations were measured at baseline, and after 6, 12, 29 and 40 weeks. At 40 weeks, the overall prevalence of having a RBC folate <906 nmol/L decreased to 18% and 35% in the 400 µg and 140 µg groups, respectively, while remaining relatively unchanged at 58% in the placebo group. After 40 weeks, there was no evidence of a difference in RBC folate between the two treatment groups (P = 0.340), nor was there evidence of a difference in the odds of a RBC folate <906 nmol/L (P = 0.078). In conclusion, the average daily intake of folic acid received from the proposed fortification program would increase RBC folate concentrations in reproductive age women to levels associated with a low risk of NTDs
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