124 research outputs found
Yukawa hierarchy from extra dimensions and infrared fixed points
We discuss the existence of hierarchy of Yukawa couplings in the models with
extra spatial dimensions. The hierarchical structure is induced by the power
behavior of the cutoff dependence of the evolution equations which yield large
suppressions of couplings at the compactification scale. The values of coupling
constants at this scale can be made stable almost independently of the initial
input parameters by utilizing the infrared fixed point. We find that the Yukawa
couplings converge to the fixed points very quickly because of the enhanced
energy dependence of the suppression factor from extra dimensions as well as in
the case of large gauge couplings at high-energy scale.Comment: 13 pages, 3 eps figure
Spatial Distributions of GABA Receptors and Local Inhibition of Ca2+ Transients Studied with GABA Uncaging in the Dendrites of CA1 Pyramidal Neurons
GABA(γ-amino-butylic acid)-mediated inhibition in the dendrites of CA1 pyramidal neurons was characterized by two-photon uncaging of a caged-GABA compound, BCMACM-GABA, and one-photon uncaging of RuBi-GABA in rat hippocampal slice preparations. Although we found that GABAA-mediated currents were diffusely distributed along the dendrites, currents elicited at the branch points of the apical dendritic trunk were approximately two times larger than those elsewhere in the dendrite. We examined the inhibitory action of the GABA-induced currents on Ca2+ transients evoked with a single back-propagating action potential (bAP) in oblique dendrites. We found that GABA uncaging selectively inhibited the Ca2+ transients in the region adjacent (<20 ”m) to the uncaging site, and that GABA uncaging was effective only within a short period after bAP (<20 ms). The strength of inhibition was linearly related to the amplitudes of the GABA currents, suggesting that the currents inhibited a sustained, subthreshold after-depolarization without preventing propagation of bAP. GABA uncaging at the dendritic branch points inhibited Ca2+ transients farther into dendritic branches (>20 ”m). Our data indicate that GABA inhibition results in spatially confined inhibition of Ca2+ transients shortly after bAP, and suggest that this effect is particularly potent at the dendritic branch points where GABA receptors cluster
Analysis of Differentially Expressed Genes in Neuroendocrine Carcinomas of the Lung
IntroductionLarge cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC) show considerable differences in their histology but share neuroendocrine (NE) characteristics and also genetic and/or expression patterns.MethodsWe used the subtractive expression method to identify differences in gene expression that would allow discrimination between these two types of NE lung carcinoma.ResultsEight cDNA fragments were transcribed at a higher level in LCNEC compared with SCLC, and these corresponded to five mitochondrial genes, two ribosomal genes, and one fetal regulation factor, neuronatin (NNAT). Immunohistochemically, NNAT protein was detected in 43% (6/14) of LCNECs but in only 8% (1/13) of SCLCs (p < 0.05). Positive staining for NNAT was observed in areas that did not show the NE morphology, such as palisading and rosettes.ConclusionsThe present results suggest that NNAT has the potential to be used as a differential maker between LCNEC and SCLC
Yukawa Hierarchy Transfer Based on Superconformal Dynamics and Geometrical Realization in String Models
We propose a scenario that leads to hierarchical Yukawa couplings and
degenerate sfermion masses at the same time, in the context of
extra-dimensional models, which can be naturally embedded in a wide class of
string models. The hierarchy of Yukawa couplings and degeneracy of sfermion
masses can be realized thanks to superconformal gauge dynamics. The sfermion
mass degeneracy is guaranteed by taking the superconformal fixed point to be
family independent. In our scenario, the origin of Yukawa hierarchy is
attributed to geometry of compactified dimensions and the consequent volume
dependence of gauge couplings in the superconformal sectors. The difference in
these gauge couplings is dynamically transferred to the hierarchy of the Yukawa
couplings. Thus, our scenario combines a new dynamical approach and the
conventional geometrical approach to the supersymmetric flavor problem.Comment: 12 pages, latex, no figur
Fermion Mass Hierarchies and Small Mixing Angles from Extra Dimensions
In this paper we study renormalization-group evolutions of Yukawa matrices
enhanced by Kaluza-Klein excited modes and analyze their infrared fixed-point
structure. We derive necessary conditions to obtain hierarchies between
generations on the fixed point. These conditions restrict how the fields in the
models can extend to higher dimension. Several specific mechanisms to realize
the conditions are presented. We also take account of generation mixing effects
and find a scenario where the mixing angles become small at low energy even
with large initial values at high-energy scale. A toy model is shown to lead
realistic quark mass matrices.Comment: 23 pages, 7 figures, LaTeX, a supplementary explanation and
references adde
First-line pembrolizumab vs chemotherapy in metastatic non-small-cell lung cancer: KEYNOTE-024 Japan subset
This prespecified subanalysis of the global, randomized controlled phase Ill KEYNOTE-024 study of pembrolizumab vs chemotherapy in previously untreated metastatic non-small-cell lung cancer without EGFR/ALK alterations and a programmed death-ligand 1 (PD-L1) tumor proportion score of 50% or greater evaluated clinical outcomes among patients enrolled in Japan. Treatment consisted of pembrolizumab 200 mg every 3 weeks (35 cycles) or platinum-based chemotherapy (four to six cycles). The primary end-point was progression-free survival; secondary end-points included overall survival and safety. Of 305 patients randomized in KEYNOTE-024 overall, 40 patients were enrolled in Japan (all received treatment: pembrolizumab, n = 21; chemotherapy, n = 19). The hazard ratio (HR) for progression-free survival by independent central review (data cut-off date, 10 July 2017) was 0.25 (95% confidence interval [CI], 0.10-0.64; one-sided, nominal P = .001). The HR for overall survival (data cut-off date, 15 February 2019) was 0.39 (95% CI, 0.17-0.91; one-sided, nominal P = .012). Treatment-related adverse events occurred in 21/21 (100%) pembrolizumab-treated and 18/19 (95%) chemotherapy-treated patients; eight patients (38%) and nine patients (47%), respectively, had grade 3-5 events. Immune-mediated adverse events and infusion reactions occurred in 11 patients (52%) and four patients (21%), respectively; four patients (19%) and one patient (5%), respectively, had grade 3-5 events. Consistent with results from KEYNOTE-024 overall, first-line pembrolizumab improved progression-free survival and overall survival vs chemotherapy with manageable safety among Japanese patients with metastatic non-small-cell lung cancer without EGFRIALK alterations and a PD-L1 tumor proportion score of 50% or greater
First-line pembrolizumab vs chemotherapy in metastatic non-small-cell lung cancer: KEYNOTE-024 Japan subset
This prespecified subanalysis of the global, randomized controlled phase III KEYNOTEâ024 study of pembrolizumab vs chemotherapy in previously untreated metastatic nonâsmallâcell lung cancer without EGFR/ALK alterations and a programmed death ligand 1 (PDâL1) tumor proportion score of 50% or higher evaluated clinical outcomes among patients enrolled in Japan. Treatment consisted of pembrolizumab 200 mg every 3 weeks (35 cycles) or platinumâbased chemotherapy (four to six cycles). The primary endâpoint was progressionâfree survival; secondary endâpoints included overall survival and safety. Of 305 patients randomized in KEYNOTEâ024 overall, 40 patients were enrolled in Japan (all received treatment: pembrolizumab, n = 21; chemotherapy, n = 19). Median progressionâfree survival was 41.4 (95% confidence interval [CI], 4.2â42.5) months with pembrolizumab and 4.1 (95% CI, 2.8â8.3) months with chemotherapy (hazard ratio [HR], 0.27 [95% CI, 0.11â0.65]; oneâsided, nominal P = .001). Median overall survival was not reached (NR) (95% CI, 22.9âNR) and 21.5 (95% CI, 5.2â35.0) months, respectively (HR, 0.39 [95% CI, 0.17â0.91]; oneâsided, nominal P = .012). Treatmentârelated adverse events occurred in 21/21 (100%) pembrolizumabâtreated and 18/19 (95%) chemotherapyâtreated patients; eight patients (38%) and nine patients (47%), respectively, had grade 3â5 events. Immuneâmediated adverse events and infusion reactions occurred in 11 pembrolizumabâtreated patients (52%) and four chemotherapyâtreated patients (21%), respectively; four patients (19%) and one patient (5%), respectively, had grade 3â5 events. Consistent with results from KEYNOTEâ024 overall, firstâline pembrolizumab improved progressionâfree survival and overall survival vs chemotherapy with manageable safety among Japanese patients with metastatic nonâsmallâcell lung cancer without EGFR/ALK alterations and a PDâL1 tumor proportion score of 50% or higher. The trial is registered with Clinicaltrials.gov: NCT02142738
Sfermion Mass Degeneracy, Superconformal Dynamics and Supersymmetric Grand Unified Theories
We discuss issues in a scenario that hierarchical Yukawa couplings are
generated through strong dynamics of superconformal field theories (SCFTs).
Independently of mediation mechanism of supersymmetry breaking, infrared
convergence property of SCFTs can provide an interesting solution to
supersymmetric flavor problem; sfermion masses are suppressed around the
decoupling scale of SCFTs and eventually become degenerate to some degree,
thanks to family-independent radiative corrections governed by the SM gaugino
masses. We discuss under what conditions the degeneracy of sfermion mass can be
estimated in a simple manner. We also discuss the constraints from lepton
flavor violations. We then study explicitly sfermion mass degeneracy within the
framework of grand unified theories coupled to SCFTs. It is found that the
degeneracy for right-handed sleptons becomes worse in the conventional SU(5)
model than in the MSSM. On the other hand, in the flipped SU(5) \times U(1)
model, each right-handed lepton is still an SU(5)-singlet, whereas the bino
mass M_1 is determined by two independent gaugino masses of SU(5) \times U(1).
These two properties enable us to have an improved degeneracy for the
right-handed sleptons. We also speculate how further improvement can be
obtained in the SCFT approach.Comment: 24 pages, latex, 4 figure
Carcinogenâinduced tumors in SFNâtransgenic mice harbor a characteristic mutation spectrum of human lung adenocarcinoma
The landscape of genetic alterations in disease models such as transgenic mice or mice with carcinogenâinduced tumors has provided a huge amount of information that has shed light on the process of tumorigenesis in human nonâsmallâcell lung cancer (NSCLC). We have previously identified stratifin (SFN) as a potent oncogene, and generated SFNâtransgenic (TgâSPCâSFN+/â) mice, which express human SFN (hSFN) only in the lung. Here, we have found that carcinogen nicotineâderived nitrosaminoketone (NNK)âinduced tumors developing in TgâSPCâSFN+/â mice show a similar histology to human lung adenocarcinoma and exhibit high hSFN expression. In order to compare the genetic characteristics of TgâSPCâSFN+/â tumors and human lung adenocarcinoma, the former were subjected to wholeâexome sequencing. Interestingly, TgâSPCâSFN+/â tumors showed the distinct distribution of exonic mutations and high number of mutated genes and transversion. Moreover, TgâSPCâSFN+/â tumors showed 73 genes that were commonly detected in more than 2 tumors, mutations of which were also found in human lung adenocarcinoma. The expression levels of some of these genes were significantly associated with the clinical outcome of lung adenocarcinoma patients. Additionally, mutated genes in TgâSPCâSFN+/â tumors were closely associated with key canonical pathways such as PI3K/AKT signaling and apoptosis signaling. These results suggest that SFN overexpression is a universal abnormality in human lung adenocarcinogenesis and TgâSPCâSFN+/â tumors recapitulate key features of major human lung adenocarcinoma. Therefore, TgâSPCâSFN+/â mice provide a useful model for clarifying the molecular mechanism underlying lung adenocarcinogenesis
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