1,753 research outputs found
Phenomenology of the Flavor-Asymmetry in the Light-Quark Sea of the Nucleon
A phenomenological ansatz for the flavor-asymmetry of the light sea
distributions of the nucleon, based on the Pauli exclusion principle, is
proposed. This ansatz is compatible with the measured flavor-asymmetry of the
unpolarized sea distributions, , of the nucleon. A prediction
for the corresponding polarized flavor-asymmetry is presented and shown to
agree with predictions of (chiral quark--soliton) models which successfully
reproduced the flavor-asymmetry of the unpolarized sea.Comment: 5 pages, LaTeX, 2 figures, uses epsfi
Introducing the concept of breast cancer stem cells
Breast tumours are well known to be composed of phenotypically diverse groups of cells. Which of these cell types contribute to tumour development, however, is not well understood. Two hypotheses exist: either all the cell population
Signatures of cosmic tau-neutrinos
The importance and signatures of cosmic tau--(anti)neutrinos have been
studied for upward-- and downward--going and hadronic shower
event rates relevant for present and future underground water or ice detectors,
utilizing the unique and reliable ultrasmall-- predictions of the dynamical
(radiative) parton model. The upward--going event rates
calculated just from cosmic fluxes are sizeably
enhanced by taking into account cosmic fluxes
and their associated fluxes as well. The coupled transport
equations for the upward--going flux traversing
the Earth imply an enhancement of the attenuated and regenerated
flux typically around GeV with respect
to the initial cosmic flux. This enhancement turns out to be smaller than
obtained so far, in particular for flatter initial cosmic fluxes behaving like
. Downward--going events and in particular the
background--free and unique hadronic `double bang' and `lollipop' events allow
to test downward--going cosmic fluxes up to
about GeV.Comment: 32 pages, 6 figures; Added reference
Tingkat Kesulitan Dinamis Menggunakan Logika Fuzzy pada Game Musik Tradisional Jawa Tengah
The culture in Indonesia is very diverse, one of which is traditional songs. However, knowledge of traditional songs is still small. Digital Games can spread knowledge about traditional songs, one of which is Central Javanese traditional songs. However, the Game that is made still has static difficulties, so the Game cannot follow the player's ability, resulting in the player feeling bored and not wanting to continue the Game. To generate dynamic difficulties, methods in artificial intelligence can be applied to Games, one of which is Fuzzy. So in this study proposed the application of dynamic difficulties using Fuzzy Logic in music Games / Rhythm Games. Fuzzy Logic is built based on mathematical values and represents uncertainty, where this logic imitates the human way of thinking. Fuzzy Logic can convert crisp input values into fuzzy sets by performing fuzzification. After the input value is converted, the input will be entered into the set of rules provided. Each rule produces a different output. After the process is complete, the output value will be converted back to the crisp output value. Based on the research conducted, it is found that Fuzzy Logic can be applied to music Games where the Game can follow the player's ability based on the given rules
Stem cells, cancer, and cancer stem cells
Stem cell biology has come of age. Unequivocal proof that stem cells exist in the haematopoietic system has given way to the prospective isolation of several tissue-specific stem and progenitor cells, the initial delineation of their properties and expressed genetic programmes, and the beginnings of their utility in regenerative medicine. Perhaps the most important and useful property of stem cells is that of self-renewal. Through this property, striking parallels can be found between stem cells and cancer cells: tumours may often originate from the transformation of normal stem cells, similar signalling pathways may regulate self-renewal in stem cells and cancer cells, and cancer cells may include 'cancer stem cells'-rare cells with indefinite potential for self-renewal that drive tumorigenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62862/1/414105a0.pd
Engineering a BCR-ABL-activated caspase for the selective elimination of leukemic cells.
Increased understanding of the precise molecular mechanisms involved in cell survival and cell death signaling pathways offers the promise of harnessing these molecules to eliminate cancer cells without damaging normal cells. Tyrosine kinase oncoproteins promote the genesis of leukemias through both increased cell proliferation and inhibition of apoptotic cell death. Although tyrosine kinase inhibitors, such as the BCR-ABL inhibitor imatinib, have demonstrated remarkable efficacy in the clinic, drug-resistant leukemias emerge in some patients because of either the acquisition of point mutations or amplification of the tyrosine kinase, resulting in a poor long-term prognosis. Here, we exploit the molecular mechanisms of caspase activation and tyrosine kinase/adaptor protein signaling to forge a unique approach for selectively killing leukemic cells through the forcible induction of apoptosis. We have engineered caspase variants that can directly be activated in response to BCR-ABL. Because we harness, rather than inhibit, the activity of leukemogenic kinases to kill transformed cells, this approach selectively eliminates leukemic cells regardless of drug-resistant mutations
Heating cancer stem cells to reduce tumor relapse
Tumour relapse is believed to be caused by rare cancer-cells with stem-cell properties (cancer stem cells) that are intrinsically resistant to available treatments. The identification of novel strategies to increase their sensitivity has major clinical implications. Latest clinical trials have shown a positive antitumoral effect of hyperthermia in combination with chemotherapy or radiotherapy. In a recent paper, the combination of increased temperature at the tumour site, generated by laser treatment of intravenously-injected gold nanoshells, and ionizing radiations enhances radiosensitivity of cancer stem cells and tumor response. At the root of the success of hyperthermia in enhancing radio-sensitization of cancer stem cells is the inhibition of their capacity to repair DNA damage, affecting the survival rate of these cells
Loss of beta-catenin triggers oxidative stress and impairs hematopoietic regeneration
Accidental or deliberate ionizing radiation exposure can be fatal due to widespread hematopoietic destruction. However, little is known about either the course of injury or the molecular pathways that regulate the subsequent regenerative response. Here we show that the Wnt signaling pathway is critically important for regeneration after radiation-induced injury. Using Wnt reporter mice, we show that radiation triggers activation of Wnt signaling in hematopoietic stem and progenitor cells. β-Catenin-deficient mice, which lack the ability to activate canonical Wnt signaling, exhibited impaired hematopoietic stem cell regeneration and bone marrow recovery after radiation. We found that, as part of the mechanism, hematopoietic stem cells lacking β-catenin fail to suppress the generation of reactive oxygen species and cannot resolve DNA double-strand breaks after radiation. Consistent with the impaired response to radiation, β-catenin-deficient mice are also unable to recover effectively after chemotherapy. Collectively, these data indicate that regenerative responses to distinct hematopoietic injuries share a genetic dependence on β-catenin and raise the possibility that modulation of Wnt signaling may be a path to improving bone marrow recovery after damage
Baryon masses and nucleon sigma terms in manifestly Lorentz-invariant baryon chiral perturbation theory
We discuss the masses of the ground state baryon octet and the nucleon sigma
terms in the framework of manifestly Lorentz-invariant baryon chiral
perturbation theory. In order to obtain a consistent power counting for
renormalized diagrams the extended on-mass-shell renormalization scheme is
applied.Comment: 18 pages, 3 figures, accepted for publication in J. Phys.
Validation study of the Being a Mother scale in a mexican sample of pregnant women.
Antecedentes: La insatisfacción con la experiencia del embarazo, puede
traer repercusiones emocionales en las mujeres por influencia de factores
cognitivos y psicosociales en torno al rol materno y la etapa del embarazo.
Objetivo: Evaluar la estructura factorial de la escala Being a Mother en
su adaptación al español, como medida de la experiencia emocional del
embarazo en una muestra de mujeres mexicanas embarazadas. Método:
Participaron 300 mujeres embarazadas, pertenecientes a clÃnicas públicas
del sector salud. Los datos se examinaron mediante el Análisis Factorial
Exploratorio, usando el Análisis Paralelo y rotación Promim, evaluando
los Ãndices de bondad de ajuste mediante el método de Hull. Resultados:
La consistencia interna es de α = .88, con evidencia de validez de
criterio evaluada con medidas de estrés (rs
= .484) y autoeficacia (rs
=
-.309) resultando significativas (p = .001). Se determinó una estructura
unidimensional que explica el 74.65% de la varianza, con adecuada validez
convergente (AVE > .5), e Ãndices de bondad de ajuste apropiados (RMSEA = .062, CFI = .99, AGFI = .99). Conclusiones: Se aporta un instrumento
con adecuadas propiedades psicométricas para evaluar la satisfacción de la
experiencia emocional del embarazo y el rol materno en mujeres
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