1,425 research outputs found
Minimal Dark Matter in the Local Extension
The minimal gauge group extension to the standard model (SM) by the local
(MBLSM) is well known as the minimal model to understand neutrino
mass origins via the seesaw mechanism, following the gauge principle. This
"small" symmetry also has deep implication to another big thing, dark matter
(DM) stability. We demonstrate it in the framework of minimal dark matter
(MDM), which aims at addressing two basic questions on DM, stability and the
nature of interactions. However, stability and perturbativity may only allow
the fermionic quintuplet. The situation is very different in the MBLSM, which
leaves the subgroup of , the matter parity ,
unbroken; it is able to stabilize all of the weakly-interacting {MDM candidates
} after assigning a proper charge. For the candidates with nonzero
hypercharge, the phenomenological challenge comes from realizing the inelastic
DM scenario thus evading the very strict DM direct detention bounds. We present
two approaches that can slightly split the CP-even and -odd parts of the
neutral components: 1) using the dimension 5 operators, which works for the
spontaneously breaking at very high scale; 2) mixing with {other
fields} having zero hypercharge, which instead works for a low
breaking scale.Comment: 13 pages without figure
Anatomical and molecular imaging of skin cancer
Skin cancer is the most common form of cancer types. It is generally divided into two categories: melanoma (∼ 5%) and nonmelanoma (∼ 95%), which can be further categorized into basal cell carcinoma, squamous cell carcinoma, and some rare skin cancer types. Biopsy is still the gold standard for skin cancer evaluation in the clinic. Various anatomical imaging techniques have been used to evaluate different types of skin cancer lesions, including laser scanning confocal microscopy, optical coherence tomography, high-frequency ultrasound, terahertz pulsed imaging, magnetic resonance imaging, and some other recently developed techniques such as photoacoustic microscopy. However, anatomical imaging alone may not be sufficient in guiding skin cancer diagnosis and therapy. Over the last decade, various molecular imaging techniques (in particular single photon emission computed tomography and positron emission tomography) have been investigated for skin cancer imaging. The pathways or molecular targets that have been studied include glucose metabolism, integrin αvβ3, melanocortin-1 receptor, high molecular weight melanoma-associated antigen, and several other molecular markers. Preclinical molecular imaging is thriving all over the world, while clinical molecular imaging has not lived up to the expectations because of slow bench-to-bedside translation. It is likely that this situation will change in the near future and molecular imaging will truly play an important role in personalized medicine of melanoma patients
Radionuclide-Based Cancer Imaging Targeting the Carcinoembryonic Antigen
Carcinoembryonic antigen (CEA), highly expressed in many cancer types, is an important target for cancer diagnosis and therapy. Radionuclide-based imaging techniques (gamma camera, single photon emission computed tomography [SPECT] and positron emission tomography [PET]) have been extensively explored for CEA-targeted cancer imaging both preclinically and clinically. Briefly, these studies can be divided into three major categories: antibody-based, antibody fragment-based and pretargeted imaging. Radiolabeled anti-CEA antibodies, reported the earliest among the three categories, typically gave suboptimal tumor contrast due to the prolonged circulation life time of intact antibodies. Subsequently, a number of engineered anti-CEA antibody fragments (e.g. Fab’, scFv, minibody, diabody and scFv-Fc) have been labeled with a variety of radioisotopes for CEA imaging, many of which have entered clinical investigation. CEA-Scan (a 99mTc-labeled anti-CEA Fab’ fragment) has already been approved by the United States Food and Drug Administration for cancer imaging. Meanwhile, pretargeting strategies have also been developed for CEA imaging which can give much better tumor contrast than the other two methods, if the system is designed properly. In this review article, we will summarize the current state-of-the-art of radionuclide-based cancer imaging targeting CEA. Generally, isotopes with short half-lives (e.g. 18F and 99mTc) are more suitable for labeling small engineered antibody fragments while the isotopes with longer half-lives (e.g. 123I and 111In) are needed for antibody labeling to match its relatively long circulation half-life. With further improvement in tumor targeting efficacy and radiolabeling strategies, novel CEA-targeted agents may play an important role in cancer patient management, paving the way to “personalized medicine”
Extra boson mix with Z boson explaining the mass of W boson
We explore the possibility of explaining the W mass with an extra gauge boson
mixing with the Z boson at tree level. Extra boson mixing with Z boson will
change the expression of Z boson mass, thus altering the W boson mass. We
explore two models in this work. We find that in the Derivative Portal Dark
Matter model, there are parameters space which can give the observed W boson
mass. And in the U(1) extension model, the kinetic mixing between extra boson
and B boson can also predict the observed W boson mass. Both model indicate an
extra vector boson with best fit mass around 120 GeV.Comment: 12 pages, 3 figure
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