246 research outputs found
Gauge-invariant description of several (2+1)-dimensional integrable nonlinear evolution equations
We obtain new gauge-invariant forms of two-dimensional integrable systems of
nonlinear equations: the Sawada-Kotera and Kaup-Kuperschmidt system, the
generalized system of dispersive long waves, and the Nizhnik-Veselov-Novikov
system. We show how these forms imply both new and well-known two-dimensional
integrable nonlinear equations: the Sawada-Kotera equation, Kaup-Kuperschmidt
equation, dispersive long-wave system, Nizhnik-Veselov-Novikov equation, and
modified Nizhnik-Veselov-Novikov equation. We consider Miura-type
transformations between nonlinear equations in different gauges.Comment: Talk given at the Workshop "Nonlinear Physics: Theory and Experiment.
V", Gallipoli (Lecce, Italy), 12-21 June, 200
Dressing chain for the acoustic spectral problem
The iterations are studied of the Darboux transformation for the generalized
Schroedinger operator. The applications to the Dym and Camassa-Holm equations
are considered.Comment: 16 pages, 6 eps figure
Functional representations of integrable hierarchies
We consider a general framework for integrable hierarchies in Lax form and
derive certain universal equations from which `functional representations' of
particular hierarchies (like KP, discrete KP, mKP, AKNS), i.e. formulations in
terms of functional equations, are systematically and quite easily obtained.
The formalism genuinely applies to hierarchies where the dependent variables
live in a noncommutative (typically matrix) algebra. The obtained functional
representations can be understood as `noncommutative' analogs of `Fay
identities' for the KP hierarchy.Comment: 21 pages, version 2: equations (3.28) and (4.11) adde
Gauge-invariant description of some (2+1)-dimensional integrable nonlinear evolution equations
New manifestly gauge-invariant forms of two-dimensional generalized
dispersive long-wave and Nizhnik-Veselov-Novikov systems of integrable
nonlinear equations are presented. It is shown how in different gauges from
such forms famous two-dimensional generalization of dispersive long-wave system
of equations, Nizhnik-Veselov-Novikov and modified Nizhnik-Veselov-Novikov
equations and other known and new integrable nonlinear equations arise.
Miura-type transformations between nonlinear equations in different gauges are
considered.Comment: 13 pages, LaTeX, no figure
ΠΠ»ΠΈΡΠ½ΠΈΠ΅ ΡΡΠ»ΠΎΠ²ΠΈΠΉ ΡΠΎΡΡΠ° ΠΈ ΠΏΠΎΡΠ»Π΅ΡΠΎΡΡΠΎΠ²ΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π½Π° ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΊΡΠΈΡΡΠ°Π»Π»ΠΎΠ² Π»Π°Π½Π³Π°ΡΠΈΡΠ°
The effects of the following factors on the optical properties of langasite crystals was studied: the growth direction for crystals of stoichiometric composition (La3Ga5SiO14) obtained in a growth atmosphere Ar+O2; growth atmosphere (Ar and Ar+O2) for crystals of stoichiometric composition; initial composition of crystals for the crystals obtained during the same conditions of growing and post-growth treatment (annealing in vacuum and in air, UV- and Ξ³ - irradiation).Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½ΠΎ Π²Π»ΠΈΡΠ½ΠΈΠ΅ Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ( ΠΈ ) ΠΈ Π°ΡΠΌΠΎΡΡΠ΅ΡΡ ΡΠΎΡΡΠ° (Ar ΠΈ Ar+O2), ΡΡΠ»ΠΎΠ²ΠΈΠΉ ΠΏΠΎΡΠ»Π΅ΡΠΎΡΡΠΎΠ²ΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ (ΠΎΡΠΆΠΈΠ³ Π² Π²Π°ΠΊΡΡΠΌΠ΅ ΠΈ Π½Π° Π²ΠΎΠ·Π΄ΡΡ
Π΅, Π£Π€- ΠΈ Ξ³ - ΠΎΠ±Π»ΡΡΠ΅Π½ΠΈΠ΅) Π½Π° ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΊΡΠΈΡΡΠ°Π»Π»ΠΎΠ² Π»Π°Π½Π³Π°ΡΠΈΡΠ°
The Participation of Calponin in the Cross Talk between 20-Hydroxyecdysone and Juvenile Hormone Signaling Pathways by Phosphorylation Variation
20-hydroxyecdysone (20E) and juvenile hormone (JH) signaling pathways interact to mediate insect development, but the mechanism of this interaction is poorly understood. Here, a calponin homologue domain (Chd) containing protein (HaCal) is reported to play a key role in the cross talk between 20E and JH signaling by varying its phosphorylation. Chd is known as an actin binding domain present in many proteins including some signaling proteins. Using an epidermal cell line (HaEpi), HaCal was found to be up-regulated by either 20E or the JH analog methoprene (JHA). 20E induced rapid phosphorylation of HaCal whereas no phosphorylation occurred with JHA. HaCal could be quickly translocated into the nuclei through 20E or JH signaling but interacted with USP1 only under the mediation of JHA. Knockdown of HaCal by RNAi blocked the 20E inducibility of USP1, PKC and HR3, and also blocked the JHA inducibility of USP1, PKC and JHi. After gene silencing of HaCal by ingestion of dsHaCal expressed by Escherichia coli, the larval development was arrested and the gene expression of USP1, PKC, HR3 and JHi were blocked. These composite data suggest that HaCal plays roles in hormonal signaling by quickly transferring into nucleus to function as a phosphorylated form in the 20E pathway and as a non-phosphorylated form interacting with USP1 in the JH pathway to facilitate 20E or JH signaling cascade, in short, by switching its phosphorylation status to regulate insect development
In Vivo RNAi Screening Identifies Regulators of Actin Dynamics as Key Determinants of Lymphoma Progression
April 1, 2010Mouse models have markedly improved our understanding of cancer development and tumor biology. However, these models have shown limited efficacy as tractable systems for unbiased genetic experimentation. Here, we report the adaptation of loss-of-function screening to mouse models of cancer. Specifically, we have been able to introduce a library of shRNAs into individual mice using transplantable EΞΌ-myc lymphoma cells. This approach has allowed us to screen nearly 1,000 genetic alterations in the context of a single tumor-bearing mouse. These experiments have identified a central role for regulators of actin dynamics and cell motility in lymphoma cell homeostasis in vivo. Validation experiments confirmed that these proteins represent bona fide lymphoma drug targets. Additionally, suppression of two of these targets, Rac2 and twinfilin, potentiated the action of the front-line chemotherapeutic vincristine, suggesting a critical relationship between cell motility and tumor relapse in hematopoietic malignancies.National Institutes of Health (U.S.) (RO1 CA128803-01)Massachusetts Institute of Technology. Dept. of Biology (Training Grant)Massachusetts Institute of Technology. Undergraduate Research Opportunities ProgramNational Cancer Institute (U.S.). Integrative Cancer Biology Program (Grant 1-U54-CA112967
Phase Ib Study of Lenvatinib Plus Pembrolizumab in Patients With Unresectable Hepatocellular Carcinoma
PURPOSE The immunomodulatory effect of lenvatinib (a multikinase inhibitor) on tumor microenvironments may contribute to antitumor activity when combined with programmed death receptor-1 (PD-1) signaling inhibitors in hepatocellular carcinoma (HCC). We report results from a phase Ib study of lenvatinib plus pembrolizumab (an anti-PD-1 antibody) in unresectable HCC (uHCC). PATIENTS AND METHODS In this open-label multicenter study, patients with uHCC received lenvatinib (bodyweight 3 treatment-related adverse events occurred in 67% (grade 5, 3%) of patients. No new safety signals were identified. CONCLUSION Lenvatinib plus pembrolizumab has promising antitumor activity in uHCC. Toxicities were manageable, with no unexpected safety signals
The use of focus group discussion methodology: Insights from two decades of application in conservation
This is the final version of the article. Available from Wiley via the DOI in this recordFocus group discussion is frequently used as a qualitative approach to gain an in-depth understanding of social issues. The method aims to obtain data from a purposely selected group of individuals rather than from a statistically representative sample of a broader population. Even though the application of this method in conservation research has been extensive, there are no critical assessment of the application of the technique. In addition, there are no readily available guidelines for conservation researchers. Here, we reviewed the applications of focus group discussion within biodiversity and conservation research between 1996 and April 2017. We begin with a brief explanation of the technique for first-time users. We then discuss in detail the empirical applications of this technique in conservation based on a structured literature review (using Scopus). The screening process resulted in 170 articles, the majority of which (67%, nΒ =Β 114,) were published between 2011 and 2017. Rarely was the method used as a stand-alone technique. The number of participants per focus group (where reported) ranged from 3 to 21 participants with a median of 10 participants. There were seven (median) focus group meetings per study. Focus group discussion sessions lasted for 90 (median) minutes. Four main themes emerged from the review: understanding of people's perspectives regarding conservation (32%), followed by the assessment of conservation and livelihoods practices (21%), examination of challenges and impacts of resource management interventions (19%) and documenting the value of indigenous knowledge systems (16%). Most of the studies were in Africa (nΒ =Β 76), followed by Asia (nΒ =Β 44), and Europe (nΒ =Β 30). We noted serious gaps in the reporting of the methodological details in the reviewed papers. More than half of the studies (nΒ =Β 101) did not report the sample size and group size (nΒ =Β 93), whereas 54 studies did not mention the number of focus group discussion sessions while reporting results. Rarely have the studies provided any information on the rationale for choosing the technique. We have provided guidelines to improve the standard of reporting and future application of the technique for conservation.N.T.O. was funded by Cambridge Overseas Trusts, The Wildlife Conservation Society, Wildlife Conservation Network and WildiZe Foundation. NM was funded by the NERC grant (NE/R006946/1), Fondation Wiener Anspach and the Scriven post doctoral fellowships. K.W. was sup-ported by the Australian Research Council Centre of Excellence for Environmental Decisions (CE11001000104) and Future Fellowship (FT100100413) programs and funded by the Australian Government
- β¦