12,251 research outputs found

    Effectiveness of Hindman's theorem for bounded sums

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    We consider the strength and effective content of restricted versions of Hindman's Theorem in which the number of colors is specified and the length of the sums has a specified finite bound. Let HTkn\mathsf{HT}^{\leq n}_k denote the assertion that for each kk-coloring cc of N\mathbb{N} there is an infinite set XNX \subseteq \mathbb{N} such that all sums xFx\sum_{x \in F} x for FXF \subseteq X and 0<Fn0 < |F| \leq n have the same color. We prove that there is a computable 22-coloring cc of N\mathbb{N} such that there is no infinite computable set XX such that all nonempty sums of at most 22 elements of XX have the same color. It follows that HT22\mathsf{HT}^{\leq 2}_2 is not provable in RCA0\mathsf{RCA}_0 and in fact we show that it implies SRT22\mathsf{SRT}^2_2 in RCA0\mathsf{RCA}_0. We also show that there is a computable instance of HT33\mathsf{HT}^{\leq 3}_3 with all solutions computing 00'. The proof of this result shows that HT33\mathsf{HT}^{\leq 3}_3 implies ACA0\mathsf{ACA}_0 in RCA0\mathsf{RCA}_0

    Effective-Range Expansion of the Neutron-Deuteron Scattering Studied by a Quark-Model Nonlocal Gaussian Potential

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    The S-wave effective range parameters of the neutron-deuteron (nd) scattering are derived in the Faddeev formalism, using a nonlocal Gaussian potential based on the quark-model baryon-baryon interaction fss2. The spin-doublet low-energy eigenphase shift is sufficiently attractive to reproduce predictions by the AV18 plus Urbana three-nucleon force, yielding the observed value of the doublet scattering length and the correct differential cross sections below the deuteron breakup threshold. This conclusion is consistent with the previous result for the triton binding energy, which is nearly reproduced by fss2 without reinforcing it with the three-nucleon force.Comment: 21 pages, 6 figures and 6 tables, submitted to Prog. Theor. Phy

    Effect of the solvent quadrupolarizability on the strength of the hydrogen bond: Theory vs data for the Gibbs energy and enthalpy of homo- and heteroassociation between carboxylic acids and water.

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    A cavity model of the effect of a solvent on thermodynamic parameters of dimerization of polar species in non-polar liquids has been developed and compared to experimental data. Bulk solution data have been collected for stearic acid in cyclohexane and in toluene to quantify the extent of self-association of the acid in terms of the dimer self-dissociation constant, Kd. Composition and temperature-dependent experimental data have been collected to determine Kd, the enthalpy of dissociation, and temperature-dependent infrared molar absorption coefficients. The interaction of stearic acid with small amounts of water present in non-aqueous solvents is also addressed and quantified with a hetero-dissociation (or dehydration) constant, Kh. Existing data for acetic acid are also considered. The model connects Kd and Kh to the vapor-phase association equilibria. Solute dipole-solvent quadrupole interactions are shown to have a major effect on Kd in quadrupolar liquids, such as toluene, benzene, and CS2. This work provides important background as a prelude to adsorption studies of these additives from non-aqueous solvents to solid surfaces with relevance to commercial fluids, such as oil-based corrosion inhibitors and friction modifiers. Moreover, the presented theory of the solvent effect on Kd is a first step to generalization of standard implicit solvent models in computational chemistry (such as the polarizable continuum model) to media of significant quadrupolar strength. This is expected to be particularly important for polar species dissolved in CO2 relevant for carbon capture and storage where appropriate models do not currently exist

    A multi-exon deletion within WWOX is associated with a 46,XY disorder of sex development

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    Disorders of sex development (DSD) are congenital conditions where chromosomal, gonad or genital development is atypical. In a significant proportion of 46,XY DSD cases it is not possible to identify a causative mutation, making genetic counseling difficult and potentially hindering optimal treatment. Here, we describe the analysis of a 46,XY DSD patient that presented at birth with ambiguous genitalia. Histological analysis of the surgically removed gonads showed bilateral undifferentiated gonadal tissue and immature testis, both containing malignant germ cells. We screened genomic DNA from this patient for deletions and duplications using an Illumina whole-genome SNP microarray. This analysis revealed a heterozygous deletion within the WWOX gene on chromosome 16, removing exons 6-8. Analysis of parental DNA showed that the deletion was inherited from the mother. cDNA analysis confirmed that the deletion maintained the reading frame, with exon 5 being spliced directly onto exon 9. This deletion is the first description of a germline rearrangement affecting the coding sequence of WWOX in humans. Previously described Wwox knockout mouse models showed gonadal abnormalities, supporting a role for WWOX in human gonad development

    Akumulasi Kromium (Cr) Pada Daging Ikan Nila Merah (Oreochromis Ssp.) Dalam Karamba Jaring Apung Di Sungai Winongo YOGYAKARTA

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    Sungai Winongo merupakan salah satu sungai penting di Yogyakarta, karena berperan dalam menunjang dan memenuhi kebutuhan hidup masyarakat sekitarnya. Tujuan penelitian ini adalah mengetahui kandungan logam berat kromium (Cr) pada air dan daging ikan nila merah di Sungai Winongo Yogyakarta serta mengetahui kelayakannya untuk dikonsumsi. Penelitian menggunakan rancangan eksplorasi dengan metode survai, dengan penetapan pengambilan sampel menggunakan teknik Purposive Random Sampling. Metode analisis uji kandungan logam berat Cr pada air dan ikan nila merah menggunakan AAS. Konsentrasi Cr pada air di Sungai Winongo Yogyakarta adalah 0,0213 mg/L, nilai ini masih berada di bawah ambang batas yang sudah ditetapkan PPRI No. 82 Tahun 2001 yakni sebesar 0,05 mg/L. Pada ikan nila merah diketahui akumulasi tertinggi pada stasiun 1 sebesar 10,2265 mg/Kg; kemudian pada stasiun 3 dan 2 sebesar 9,81075 mg/Kg dan 9,2245 mg/Kg. Nilai ini melebihi baku mutu yang sudah ditetapkan oleh Dirjen POM 1989 yakni sebesar 2,5 mg/Kg. Simpulan dari penelitian ini adalah kandungan Cr dalam air masih di bawah ambang batas. Ikan nila merah di sungai Winongo sudah mengakumulasi Cr di atas ambang batas, sehingga tidak layak konsumsi.Winongo river is one of the important rivers in Yogyakarta because this supports and fulfils the people's needs. The purpose of this study was to determine the heavy metal content of Cr in water and red tilapia fish meat captured in Winongo Yogyakarta and to know whether the meat is edible or not. The study design was used exploration design with survey method, in which the determination of sampling was using purposive random sampling. Method of test analysis of heavy metals Cr in water and red tilapia was using AAS. Chromium concentration in water of Winongo river was 0.0213 mg/l, this value remains below the threshold set by PPRI No. 82 year 2001 which was 0.05 mg/L, the highest accumulation of Cr in red tilapia meat was at station 1 i.e. 10.2265 mg/Kg; followed by station 3 and 2 by 9.8108 mg/Kg and 9.2245 mg/Kg, respectively. Thiese values exceed the standard quality set forth by the Director General of POM in 1989 i.e. 2.5 mg/Kg. The conclusion was that Cr content in the water is still below the threshold but Tilapia fishes in Winongo river accumulated Cr above the threshold, so that people better not consume red tilapia fish

    Farkas-Type Results for Vector-Valued Functions with Applications

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    The main purpose of this paper consists of providing characterizations of the inclusion of the solution set of a given conic system posed in a real locally convex topological space into a variety of subsets of the same space defined by means of vector-valued functions. These Farkas-type results are used to derive characterizations of the weak solutions of vector optimization problems (including multiobjective and scalar ones), vector variational inequalities, and vector equilibrium problems.This research was partially supported by MINECO of Spain and FEDER of EU, Grant MTM2014-59179-C2-1-P, by the project DP160100854 from the Australian Research Council, and by the project B2015-28-04: “A new approach to some classes of optimization problems” from the Vietnam National University - HCM city, Vietnam

    Zinc transporter HKE4 as a new target in antihormone resistance of breast cancer

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    Background Oestrogen receptor-positive breast cancers develop resistance to anti-oestrogens by utilising alternative growth factor pathways as observed in our tamoxifen-resistant cell line (TAMR). These include EGFR, IGF1-R and Src signalling as well as increased growth and invasion. Zinc is elevated in breast cancer tissue and has been demonstrated to activate certain growth factor signalling pathways. We have tested the expression level of members of the LIV-1 family of zinc influx transporters and discovered that HKE4 (SLC39A7, ZIP7), previously shown by us capable of increasing the intracellular zinc levels, has increased expression in TAMR. We have therefore investigated whether the development of the more aggressive phenotype observed in our TAMR cells, including activation of these signalling pathways as well as increased growth and invasion, is due to an increase of intracellular zinc and as a direct result of increased expression of HKE4. Methods All nine members of the LIV-1 subfamily of ZIP transporters were measured in our model of tamoxifen-resistant breast cancer using Affymetrix arrays. Zinc-induced activation of growth factor signalling pathway components was investigated by western blot and/or fluorescent microscopy. Short-term (15-min) treatments with 20 μM zinc included ionophore, whereas long-term (hours/days) did not. Recombinant LIV-1 family members with a V5 tag were expressed using pcDNA3.1/V5-His-TOPO vector, and siRNA (Dharmacon smartpools with relevant controls) was used to reduce endogenous expression. Results HKE4 (SLC39A7), a ZIP transporter from the LIV-1 subfamily, was discovered to be elevated in TAMR cells by Affymetrix analysis and confirmed by PCR and western blot. We have observed that our TAMR cells have a twofold increase in intracellular zinc compared with wild-type cells, using the zinc-specific fluorescent dye Newport Green. Short-term zinc treatment of TAMR cells activates the signalling pathways implicated in antihormone-resistant proliferation and is reduced by both the zinc chelator TPEN and the Src kinase inhibitor SU6556. The same effects are observed after longer term (6 days) zinc treatment with additional increases in cell growth and invasion through Matrigel. Since we have previously demonstrated that HKE4 is capable of increasing intracellular zinc in cells and, more recently, that these TAMR have elevated intracellular zinc levels, we have tested the hypothesis that elevated HKE4 expression is directly responsible for the aggressive phenotype observed in our TAMR cells. Reducing HKE4 levels by siRNA demonstrated a role for this molecule in driving the zinc-induced activation of multiple signalling pathways. In the presence of siRNA for HKE4, the previously observed zinc-induced activation of EGFR, Src, and IGF1-R was eradicated and the EGF-stimulated activation was also decreased. Additionally, we have demonstrated the converse by transfecting recombinant HKE4 into wild-type cells and/or treating them with zinc to observe the activation of these signalling pathways and increases in invasive capability. Interestingly, we have observed a similar role of HKE4 in our model of faslodex-resistant breast cancer. Conclusion The presented results propose that HKE4, a member of the LIV-1 subfamily of ZIP transporters, is directly involved in the activation of the aggressive phenotype observed with the development of antihormone resistance, and as such is a potential new target for the prevention of resistance to antihormones in breast cancer progression
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