168 research outputs found
A Clinical Trial of the Effects of Oral Beta-Carotene on the Responses of Human Skin to Solar Radiation
Beta-carotene (180 mg/day, p. o. ) or a placebo was administered to 30 normal male volunteers for 10 weeks, after which the volunteers were exposed to sunlight in the Arizona desert for up to 2 hours. Beta-carotene had a small but statistically significant effect in increasing the minimal erythema dose of sunburn radiation. The observed effects were too small to recommend the use of beta-carotene as a photoprotective agent for sunburn, but the methods developed provide a workable model for randomized controlled trials for evaluating the efficacy of systemic photoprotective agents
Pair Production of Neutral Higgs Bosons through Noncommutative QED Interactions at Linear Colliders
We study the feasibility of detecting noncommutative (NC) QED through neutral
Higgs boson (H) pair production at linear colliders (LC). This is based on the
assumption that H interacts directly with photon in NCQED as suggested by
symmetry considerations and strongly hinted by our previous study on
\pi^0-photon interactions. We find the following striking features as compared
to the standard model (SM) result: (1) generally larger cross sections for an
NC scale of order 1 TeV; (2) completely different dependence on initial beam
polarizations; (3) distinct distributions in the polar and azimuthal angles;
and (4) day-night asymmetry due to the Earth's rotation. These will help to
separate NC signals from those in the SM or other new physics at LC. We
emphasize the importance of treating properly the Lorentz noninvariance problem
and show how the impact of the Earth's rotation can be used as an advantage for
our purpose of searching for NC signals.Comment: 12 pages, 3 figures using axodraw.sty; v2: proof version in Phys.
Rev. D, minor rewordin
Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins
New formulation of relativistic wave equations (RWE) for massive particles
with arbitrary half-integer spins s interacting with external electromagnetic
fields are proposed. They are based on wave functions which are irreducible
tensors of rank n=s-\frac12$) antisymmetric w.r.t. n pairs of indices,
whose components are bispinors. The form of RWE is straightforward and free of
inconsistencies associated with the other approaches to equations describing
interacting higher spin particles
Recoil-Induced-Resonances in Nonlinear, Ground-State, Pump-Probe Spectroscopy
A theory of pump-probe spectroscopy is developed in which optical fields
drive two-photon Raman transitions between ground states of an ensemble of
three-level atoms. Effects related to the recoil the atoms undergo
as a result of their interactions with the fields are fully accounted for in
this theory. The linear absorption coefficient of a weak probe field in the
presence of two pump fields of arbitrary strength is calculated. For subrecoil
cooled atoms, the spectrum consists of eight absorption lines and eight
emission lines. In the limit that , where and
are the Rabi frequencies of the two pump fields, one recovers the
absorption spectrum for a probe field interacting with an effective two-level
atom in the presence of a single pump field. However when , new interference effects arise that allow one to selectively turn on
and off some of these recoil induced resonances.Comment: 30 pages, 8 figures. RevTex. Submitted to Phys. Rev. A, Revised
versio
Expression of the pluripotency transcription factor OCT4 in the normal and aberrant mammary gland
Breast cancers with lactating features, some of which are associated with pregnancy and lactation, are often poorly differentiated, lack estrogen receptor, progesterone receptor, and HER2 expression and have high mortality. Very little is known about the molecular mechanisms that drive uncontrolled cell proliferation in these tumors and confer lactating features. We have recently reported expression of OCT4 and associated embryonic stem cell self-renewal genes in the normal lactating breast and breastmilk stem cells (hBSCs). This prompted us to examine OCT4 expression in breast cancers with lactating features and compare it with that observed during normal lactation, using rare specimens of human lactating breast. In accordance with previous literature, the normal resting breast (from non-pregnant, non-lactating women) showed minimal OCT4 nuclear expression (0.9%). However, this increased in the normal lactating breast (11.4%), with further increase in lactating adenomas, lactating carcinomas, and pregnancy-associated breast cancer (30.7-48.3%). OCT4 was expressed in the epithelium and at lower levels in the stroma, and was co-localized with NANOG. Comparison of normal non-tumorigenic hBSCs with OCT4-overexpressing tumorigenic breast cell lines (OTBCs) demonstrated upregulation of OCT4, SOX2, and NANOG in both systems, but OTBCs expressed OCT4 at significantly higher levels than SOX2 and NANOG. Similar to hBSCs, OTBCs displayed multi-lineage differentiation potential, including the ability to differentiate into functional lactocytes synthesizing milk proteins both in vitro and in vivo. Based on these findings, we propose a hypothesis of normal and malignant transformation in the breast, which centers on OCT4 and its associated gene network. Although minimal expression of these embryonic genes can be seen in the breast in its resting state throughout life, a controlled program of upregulation of this gene network may be a potential regulator of the normal remodeling of the breast toward a milk-secretory organ during pregnancy and lactation. Deregulation of this gene network either within or outside pregnancy and lactation may lead to aberrant breast cell proliferation and malignant transformation, suggesting a role of these genes in both normal lactation and breast oncogenesis
Probing Noncommutative Space-Time in the Laboratory Frame
The phenomenological investigation of noncommutative space-time in the
laboratory frame are presented. We formulate the apparent time variation of
noncommutativity parameter in the laboratory frame due to the
earth's rotation. Furthermore, in the noncommutative QED, we discuss how to
probe the electric-like component
by the
process at future linear collider.
We may determine the magnitude and the direction of
by detailed study of the apparent time
variation of total cross section.
In case of us observing no signal, the upper limit on the magnitude of
can be determined independently of its
direction.Comment: 12 pages, 7 figures, typos are corrected, one graph have been added
in figure
Emotional valence and arousal affect reading in an interactive way: neuroimaging evidence for an approach-withdrawal framework
A growing body of literature shows that the emotional content of verbal material affects reading, wherein emotional words are given processing priority compared to neutral words. Human emotions can be conceptualised within a two-dimensional model comprised of emotional valence and arousal (intensity). These variables are at least in part distinct, but recent studies report interactive effects during implicit emotion processing and relate these to stimulus-evoked approach-withdrawal tendencies. The aim of the present study was to explore how valence and arousal interact at the neural level, during implicit emotion word processing. The emotional attributes of written word stimuli were orthogonally manipulated based on behavioural ratings from a corpus of emotion words. Stimuli were presented during an fMRI experiment while 16 participants performed a lexical decision task, which did not require explicit evaluation of a word's emotional content. Results showed greater neural activation within right insular cortex in response to stimuli evoking conflicting approach-withdrawal tendencies (i.e., positive high-arousal and negative low-arousal words) compared to stimuli evoking congruent approach vs. withdrawal tendencies (i.e., positive low-arousal and negative high-arousal words). Further, a significant cluster of activation in the left extra-striate cortex was found in response to emotional than neutral words, suggesting enhanced perceptual processing of emotionally salient stimuli. These findings support an interactive two-dimensional approach to the study of emotion word recognition and suggest that the integration of valence and arousal dimensions recruits a brain region associated with interoception, emotional awareness and sympathetic functions
Amplitudes With Different Helicity Configurations Of Noncommutative QED
The amplitudes of purely photonic and photon{2-fermion processes of non-
commutative QED (NCQED) are derived for different helicity configurations of
photons. The basic ingredient is the NCQED counterpart of Yang-Mills recursion
relations by means of Berends and Giele. The explicit solutions of recursion
relations for NCQED photonic processes with special helicity configurations are
presented.Comment: 23 pages, 2 figure
Measuring water use in a green economy, A report of the Working Group on water Efficiency to the International Resource Panel
The relationship between efavirenz as initial antiretroviral therapy and suicidal thoughts among HIV-infected adults in routine care
Background: Evidence about the effect of initiating efavirenz-containing combination antiretroviral therapy (ART) as the first-line therapy on suicidal thoughts remains conflicting. Methods: Using data from a cohort of HIV-infected adults enrolled in routine care across 5 sites in the United States, we included participants with a baseline patient-reported outcome measure and detectable viral load who initiated ART between 2011 and 2014. Participants were followed until the earliest of the following: first suicidal thoughts, discontinuation of initial ART regimen, death, loss to care (>12 months with no HIV appointments), or administrative censoring (2014-2015). Suicidal thoughts were measured using a Patient Health Questionnaire-9 item. We used weighted marginal structural Cox models to estimate the effect of initiating efavirenz-containing ART, versus efavirenz-free ART, on the hazard of active or passive suicidal thoughts after ART initiation, accounting for confounding by channeling bias. Results: Overall, 597 participants were followed for a median of 19 months (13, 132 total person-months); 147 (25%) initiated efavirenz-containing ART. At ART initiation, 38% of participants reported suicidal thoughts or depressive symptoms. Initiating efavirenz-based ART was associated with a hazard ratio (HR) for suicidal thoughts below the null in the crude analysis [HR, 0.88; 95% confidence interval (CI): 0.53 to 1.45] and above the null in the weighted analysis (HR, 1.21; 95% CI: 0.66 to 2.28). Among those with a prior mental health issue, the weighted HR was 1.76 (95% CI: 0.45 to 6.86). Conclusions: After accounting for measured channeling bias, we observed no strong evidence that initiating efavirenz-containing ART increased the hazard of suicidal thoughts
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