Low-energy nuclear reactions with double-solenoid-based radioactive nuclear beam

The University of Notre Dame, USA (Becchetti et al, Nucl. Instrum. Methods Res. A505, 377 (2003) and later the University of São Paulo, Brazil (Lichtenthaler et al, Eur. Phys. J. A25, S-01, 733 (2005)) adopted a system based on superconducting solenoids to produce low-energy radioactive nuclear beams. In these systems the solenoids act as thick lenses to collect, select, and focus the secondary beam into a scattering chamber. Many experiments with radioactive light particle beams (RNB) such as ⁶He, ⁷Be, ⁸Li, ⁸B have been performed at these two facilities. These low-energy RNB have been used to investigate low-energy reactions such as elastic scattering, transfer and breakup, providing useful information on the structure of light nuclei near the drip line and on astrophysics. Total reaction cross-sections, derived from elastic scattering analysis, have also been investigated for light system as a function of energy and the role of breakup of weakly bound or exotic nuclei is discussed.     

Synthesis,in vitro $$\alpha $$-glucosidase inhibitory activity,and in silico study of ( E)-thiosemicarbazones and ( E)-2-(2-(arylmethylene)hydrazinyl)-4-arylthiazole derivatives

This study is focused on the identification of thiazole-based inhibitors for the \(\alpha \)-glucosidase enzyme. For that purpose, (E)-2-(2-(arylmethylene)hydrazinyl)-4-arylthiazole derivatives were synthesized in two steps and characterized by various spectroscopic techniques. All derivatives and intermediates were evaluated for their in vitro \(\alpha \)-glucosidase inhibitory activity. Thiosemicarbazones 20 and 35, and cyclized thiazole derivatives 2, 5–11, 13, 15, 21–24, 27–31, and 36–37 showed significant inhibitory potential in the range of \(\hbox {IC}_{50}=6.2\pm 0.19\)–\(43.6\pm 0.23~\upmu \hbox {M}\) as compared to standard acarbose (\(\hbox {IC}_{50}=37.7\pm 0.19~\upmu \hbox {M}\)). A molecular modeling study was carried out to understand the binding interactions of compounds with the active site of enzyme.     

Synthesis of novel 7-aryl and 7-spiropyrazolo[4′,3′:5,6]pyrido[2,3-<Emphasis Type="BoldItalic">d</Emphasis>]pyrimidine derivatives and their study as AChE inhibitors

An efficient route for the synthesis of novel 7-aryl and 7-spiropyrazolo[4\(^{\prime }\),3\(^{\prime }\):5,6]pyrido[2,3-d]pyrimidine derivatives is described. These compounds were obtained by a cyclocondensation reaction between pyrazolopyridinediamines 4 and aldehydes 5 or cyclic ketones 6 in the presence of acetic acid as catalyst. This procedure provides the desired compounds in good yields under a simple two-step methodology. The obtained compounds were evaluated as AChE inhibitors and showed weak AChe inhibition with \(\hbox {IC}_{50} = 115{-}470 \, \upmu \hbox {M}\).     

The photomagneton\hat B^{\left( 3 \right)} and electrodynamic conservation lawsand electrodynamic conservation laws

It is shown that the basic electrodynamical conservation laws are unaffected by the presence in free space of the photomagneton of light, $\hat B^{\left( 3 \right)} = B^{\left( 0 \right)} \hat J/\rlap{--} h$ , the fundamental photon property responsible for magnetization by light. The expectation value $B^{\left( 3 \right)} = \left\langle {\hat B^{\left( 3 \right)} } \right\rangle $ does not affect the Poynting vector, so that it does not contribute to electromagnetic flux density. The electromagnetic energy density can be expressed in terms ofB ⁽³⁾ through the equation $$\rlap{--} h\omega = \frac{1}{{\mu _0 }}\smallint B^{\left( 3 \right)} \cdot B^{\left( 3 \right) * } dV.$$ When light magnetizes matter, the unitB ⁽³⁾ of magnetic flux density per photon is transferred from light to matter. This is equivalent to an elastic transfer of angular momentum. Experimental indications for the existence ofB ⁽³⁾ are discussed.     

Positions of the magnetoroton minima in the fractional quantum Hall effect

The multitude of excitations of the fractional quantum Hall state are very accurately understood, microscopically, as excitations of composite fermions across their Landau-like Λ levels. In particular, the dispersion of the composite fermion exciton, which is the lowest energy spin conserving neutral excitation, displays filling-factor-specific minima called “magnetoroton” minima. Simon and Halperin employed the Chern-Simons field theory of composite fermions [Phys. Rev. B 48, 17368 (1993)] to predict the magnetoroton minima positions. Recently, Golkar et al. [Phys. Rev. Lett. 117, 216403 (2016)] have modeled the neutral excitations as deformations of the composite fermion Fermi sea, which results in a prediction for the positions of the magnetoroton minima. Using methods of the microscopic composite fermion theory we calculate the positions of the roton minima for filling factors up to 5/11 along the sequence s/ (2s + 1) and find them to be in reasonably good agreement with both the Chern-Simons field theory of composite fermions and Golkar et al.’s theory. We also find that the positions of the roton minima are insensitive to the microscopic interaction in agreement with Golkar et al.’s theory. As a byproduct of our calculations, we obtain the charge and neutral gaps for the fully spin polarized states along the sequence s/ (2s ± 1) in the lowest Landau level and the n = 1 Landau level of graphene.     

A f acile,regioselective synthesis of novel 3-( N-phenylc arbox amide)pyr azolo[1,5- a]pyrimidine an alogs in the presence of KHSO$$_{}$$ in aqueous medi a assisted by ultr asound and their antib acteri al activities

An environmentally benign, simple, efficient, and convenient route is described for the synthesis of novel pyrazolo[1,5-a]pyrimidine derivatives under ultrasound irradiation. Condensation of aminopyrazole 5 with formylated active proton compounds (6, 8, E–G, 12, and 15) furnished pyrazolopyrimidine (7, 9, 10, 13, and 16) in high-to-excellent yields. In comparison with conventional methods, ultrasound irradiation offers several advantages, such as shorter reaction time, higher yields, milder conditions, and environmental friendliness. The reaction is clean with excellent yields and reduces the use of solvents. X-ray crystallographic study of compound 7c confirmed the regioselectivity of the reaction. The antibacterial profile of the newly synthesized compounds was evaluated by cup and saucer method.     

Ni(II) and Zn(II) Complexes Containing Alkynyl Functionalized Salicylaldimine Ligand and Heterocyclic Coligand: Synthesis,Characterization and Luminescence Properties

Some nickel(II) and zinc(II) complexes of the type [Ni(L)(phen/bipy)]X (1a–6a) and [Zn(L) (phen/bipy)]X (1b–6b) (where L = 2-{(E)-[(4-trimethylsilylethynylphenyl)imino]methyl}-4-(4-nitro phenylethynyl)phenol; phen = 1, 10-phenanthroline, bipy = 2, 2´-bipyridine; X = ClO₄ ^?, BF₄ ^?, PF₆ ^?) have been prepared and characterized on the basis of elemental analyses, FTIR, ¹H NMR and mass spectral studies. The molecular structure of L was determined by single crystal X-ray diffraction studies. The electrochemical behaviour of the Ni(II) complexes indicate that the phen complexes appears at more positive potential as compared to those for bipy complexes, as a consequence of its strong π-acidic character. TGA was carried out to study the thermal behavior of the complexes. Room temperature luminescence is observed for all complexes corresponds to π → π* ILCT transition. The size of the counter anion and heterocyclic coligands phen and bipy shows marked effect on emission properties of the complexes.     

Photon electrodynamics and photon structure as a bunch of one of many possible states of electromagnetic field

Fundamental laws of conservation are used to show that electromagnetic field is generally represented (even in vacuum at ρ = 0 and j = 0) using four vectors D, E, B, and H with different equations of state (material equations) that are linear for electromagnetic waves and nonlinear for photons and particles. An equation that describes different states of electromagnetic field (i.e., different but not arbitrary relationships of field vectors E, H, D, and B) is derived. It is shown that electromagnetic wave and photon are different states of electromagnetic field that exhibit different dependences of energy density on field vectors. Partial analytical solutions are obtained for a photon (spatially localized bunch of electromagnetic field energy) that propagates at a velocity of light along a single (as distinct from electromagnetic wave) direction.     

Temperature dependent atomic transport properties of liquid Sn

A simple analytical model for atomic motion of Tankeshwar et al. [J. Phys.: Condens. Matter 3, 3173 (1991)] is used to obtain velocity autocorrelation function (VACF) with the inter-atomic potential and the pair correlation function as required inputs for liquid Sn. For the electron-ion interaction the modified empty-core potential is used, which represents the orthogonalisation effect due to s-core states in such sp-bonded metals. Temperature dependence of structure factor is considered through temperature dependent potential parameter in the pair potential. The coherent behaviour of liquid Sn in terms of the dynamic structure factor employing viscoelastic theory has also been studied. Intrinsic temperature effect has been studied through damping term\hbox{${\exp}( {-\frac{{\pi k}_{{B}} {T}}{{2k}_{{F}} }{r}} )$} exp (?πkBT2kFr)in the pair potential. The predicted results for VACF, cosine power spectrum, mean square displacement, diffusion and viscosity coefficients have been compared with recent available data, and a good agreement has been achieved.     

Copper(I) Complexes of N-(2-{[(2E)-2-(4-Nitrobenzylidenyl)Hydrazinyl]Carbonyl}Phenyl)Benzamide and Triphenylphosphine: Synthesis,Characterization and Luminescence Properties

Copper(I) complexes of the formula [Cu(L)(PPh₃)₂]X (1–4) (X = Cl(1), ClO₄(2), BF₄(3) and PF₆(4)) [where L = N-(2-{[(2E)-2-(4-nitrobenzylidenyl)hydrazinyl]carbonyl}phenyl)benzamide; PPh₃ = triphenylphosphine] have been prepared by the condensation of N-[2-(hydrazinocarbonyl)phenyl]benzamide with 4-nitrobenzaldehyde followed by the reaction with CuCl, [Cu(MeCN)₄]ClO₄, [Cu(MeCN)₄]BF₄ and [Cu(MeCN)₄]PF₆ in presence of triphenylphosphine as a coligand. Complexes 1–4 were then characterized by elemental analyses, FTIR, UV-visible and ¹H NMR spectroscopy. Mononuclear copper(I) complexes 1–4 were formed with L in its keto form by involvement of azomethine nitrogen and the carbonyl oxygen along with two PPh₃ groups. A single crystal X-ray diffraction study of the representative complex [(Cu(L)(PPh₃)₂]CIO₄ (2) reveals a distorted tetrahedral geometry around Cu(I). Crystal data of (2): space group = C2/c, a = 42.8596 (9) Å, b = 14.6207 (3) Å, c = 36.4643 (7) Å, V = 20,653.7 (7) ų, Z = 16. Complexes 1–4 exhibit quasireversible redox behaviour corresponding to a Cu(I)/Cu(II) couple. All complexes show blue-green emission as a result of fluorescence from an intra-ligand charge transition (ILCT), ligand to ligand charge transfer transition (LLCT) or mixture of both. Significant increase in size of the counter anion shows marked effect on quantum efficiency and lifetime of the complexes in solution.     

Performance of a GEM-TPC prototype

A GEM-TPC detector was build as a prototype of the inner tracker for the future $\overline{\rm P}$ ANDA experiment at FAIR and as an updgrade for the FOPI experiment at GSI. A GEM-TPC can exploit the intrinsic suppression of back?drifting (Lyashenko?A et?al., Nucl Instrum Methods A 598:116, 2009) ions from the amplification stage of the GEM foils to overcome the problem of drift-field distortions in a ungated operation. This prototype was designed to fit into the FOPI spectrometer, where the commissioning, tests with cosmic rays and beam tests were carried out (Fabbietti, Nucl Instrum Methods A 628:204–208, 2011).     

Ising Critical Exponents on Random Trees and Graphs

We study the critical behavior of the ferromagnetic Ising model on random trees as well as so-called locally tree-like random graphs. We pay special attention to trees and graphs with a power-law offspring or degree distribution whose tail behavior is characterized by its power-law exponent τ > 2. We show that the critical inverse temperature of the Ising model equals the hyperbolic arctangent of the reciprocal of the mean offspring or mean forward degree distribution. In particular, the critical inverse temperature equals zero when ${\tau \in (2,3]}$ where this mean equals infinity. We further study the critical exponents δ, β and γ, describing how the (root) magnetization behaves close to criticality. We rigorously identify these critical exponents and show that they take the values as predicted by Dorogovstev et al. (Phys Rev E 66:016104, 2002) and Leone et al. (Eur Phys J B 28:191–197, 2002). These values depend on the power-law exponent τ, taking the same values as the mean-field Curie-Weiss model (Exactly solved models in statistical mechanics, Academic Press, London, 1982) for τ > 5, but different values for ${\tau \in (3,5)}$ .     

Resonant scattering of an X-ray photon by a heavy atom

The influence of many-body and relativistic effects on the absolute values and shape of the double differential cross section for the resonant scattering of a linearly polarized X-ray photon by a free xenon atom near the K-shell ionization threshold has been theoretically analyzed. The evolution of the spatially extended structure of the scattering cross section to the K _{α, β} structure of the X-ray spectrum of the xenon atom emission has been demonstrated. The calculations have been performed in the dipole approximation for the anomalous dispersion component of the total inelastic scattering amplitude and in the impulse approximation for the contact component of this amplitude. The contribution of the Rayleigh (elastic) scattering component is taken into account using the methods developed in Hopersky et al., J. Phys. B 30, 5131 (1997). The effects of the radial relaxation of the electron shells, spin-orbit splitting, double excitation/ionization of the atomic ground state, as well as the Auger and radiative decays of the produced main vacancies, are considered. Using the results obtained by Tulkki, Phys. Rev. A 32, 3153 (1985) and Biggs et al., At. Data Nucl. Data Tables 16, 201 (1975), the nonrelativistic Hartree-Fock wavefunctions are changed to the relativistic Dirac-Hartree-Fock wavefunctions of the single-particle scattering states when constructing the process probability amplitude. The calculations are predicting and are in good agreement with the synchrotron experiment on the measurement of the absolute values and shape of the double differential cross section for the resonant scattering of an X-ray photon by a free xenon atom reported by Czerwinski et al., Z. Phys. A 322, 183 (1985).     

Domain and Range of the Modified Wave Operator for Schrödinger Equations with a Critical Nonlinearity

We study the final problem for the nonlinear Schrödinger equation

$i{\partial }_{t}u+\frac{1}{2}\Delta u=\lambda|u|^{\frac{2}{n}}u,\quad (t,x)\in {\mathbf{R}}\times \mathbf{R}^{n},$

where\(\lambda \in{\bf R},n=1,2,3\). If the final data\(u_{+}\in {\bf H}^{0,\alpha }=\left\{ \phi \in {\bf L}^{2}:\left( 1+\left\vert x\right\vert \right) ^{\alpha }\phi \in {\bf L}^{2}\right\} \) with\(\frac{ n}{2} < \alpha < \min \left( n,2,1+\frac{2}{n}\right) \) and the norm\(\Vert \widehat{u_{+}}\Vert _{{\bf L}^{\infty }}\) is sufficiently small, then we prove the existence of the wave operator in L ². We also construct the modified scattering operator from H ^0,α to H ^0,δ with\(\frac{n}{2} < \delta < \alpha\).

     

Synthesis,characterization and molecular docking studies of thiouracil derivatives as potent thymidylate synthase inhibitors and potential anticancer agents

Thymidylate synthase (TS), one of folate-dependent enzymes, is a key and well-recognized target for anticancer agents. In this study, a series of 6-aryl-5-cyano thiouracil derivatives were designed and synthesized in accordance with essential pharmacophoric features of known TS inhibitors. Nineteen compounds were screened in vitro for their anti-proliferative activities toward HePG-2, MCF-7, HCT-116, and PC-3 cell lines. Compounds \(\mathbf{21}_{\mathbf{c}}\), \(\mathbf{21}_{\mathbf{d}}\), and 24 exhibited high anti-proliferative activity, comparable to that of 5-fluorouracil. Additionally, ten compounds with potent anti-proliferative activities were further evaluated for their ability to inhibit TS enzyme. Six compounds (\(\mathbf{21}_{\mathbf{b}}\), \(\mathbf{21}_{\mathbf{c}}\), \(\mathbf{21}_{\mathbf{d}}\), 22, 23 and 24) demonstrated potent dose-related TS inhibition with \(\hbox {IC}_{50}\) values ranging from 1.57 to \(3.89\,\upmu \hbox {M}\). The in vitro TS activity results were consistent with those of the cytotoxicity assay where the most potent anti-proliferative compounds of the series showed good TS inhibitory activity comparable to that of 5-fluorouracil. Furthermore, molecular docking studies were carried out to investigate the binding pattern of the designed compounds with the prospective target, TS (PDB-code: 1JU6).     

Experimental determination of the scattering length for positron scattering from krypton

We report the first experimentally supported determination of the scattering length for positron scattering from krypton. Our result of  ?10.3 ± 1.5 a.u. compares favourably with that from a convergent close coupling calculation performed as a part of this investigation (?9.5 a.u.), and also with an earlier many body theory calculation of  ?10.1 a.u. from Gribakin and Ludlow [Phys. Rev. A 70, 032720 (2004)] and a polarized-orbital result of  ?10.4 a.u. from McEachran et al. [J. Phys. B 13, 1281 (1980)]. The present experimental scattering length supports the existence of a low-lying positron-krypton virtual state (Surko et al. [J. Phys. B 38, R57 (2005)]) at an energy ε = 0.13 eV.     

Synthesis and evaluation of bile acid amides of $$\alpha $$-cyanostilbenes as anticancer agents

A series of amino-substituted \(\alpha \)-cyanostilbene derivatives and their bile acid (cholic and deoxycholic acid) amides were designed and synthesized. A comparative study on the anticancer and antibacterial activity evaluation on the synthesized analogs was carried against the human osteosarcoma (HOS) cancer cell line, and two gram ?ve (E. coli and S. typhi) and two gram \(+\)ve (B. subtilis and S. aureus) bacterial strains. All the cholic acid \(\alpha \)-cyanostilbene amides showed an \(\hbox {IC}_{50}\) in the range 2–13 \(\upmu \hbox {M}\) against human osteosarcoma cells (HOS) with the most active analog (6g) possessing an \(\hbox {IC}_{50}\) of \(2\,\upmu \hbox {M}\). One of the amino-substituted \(\alpha \)-cyanostilbene, 4e, was found to possess an \(\hbox {IC}_{50}\) of \(3\,\upmu \hbox {M}\). An increase in the number of cells at the sub-\(\hbox {G}_{1}\) phase of the cell was observed in the in vitro cell cycle analysis of two most active compounds in the series (4e, 6g) suggesting a clear indication toward induction of apoptotic cascade. With respect to antibacterial screening, amino-substituted \(\alpha \)-cyanostilbenes were found to be more active than their corresponding bile acid amides. The synthesized compounds were also subjected to in silico study to predict their physiochemical properties and drug-likeness score.     

Synthesis and antifungal activity of dehydroabietic acid-based 1,3,4-thiadiazole-thiazolidinone compounds

In an attempt to search for new natural products-based antifungal agents, a series of novel dehydroabietic acid derivatives bearing a 1,3,4-thiadiazole-thiazolidinone moiety were designed and synthesized. The primary bioassay used showed that at a concentration of \(50\,\upmu \hbox {g}/\hbox {mL}\), the target compounds 3c, 3f, and 3n exhibited excellent antifungal activity (91.3 % inhibition) against Gibberella zeae, which was equivalent to the commercial antifungal drug azoxystrobin (positive control).     

Skeletal modifications of $$\upbeta $$-carboline alkaloids and their antiviral activity profile

To study the effect of the variation of fused ring size and substitution on the antiviral activity of \(\upbeta \)-carboline alkaloids, four types of structurally novel \(\upbeta \)-carboline alkaloids analogues, with indole-fused six- to nine-membered-rings motifs, were designed, synthesized, and evaluated for the inhibition of tobacco mosaic virus (TMV). Bioassay results indicated that most of these analogues had significant anti-TMV activity; especially I-14 (54 \(\pm \) 3 % at 500 \(\upmu \)g/mL in vitro; 51 \(\pm \) 2, 45 \(\pm \) 2, and 42 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vivo), II-4 (53 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vitro; 49 \(\pm \) 2, 57 \(\pm \) 2, and 48 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vivo), and II-8 (48 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vitro; 53 \(\pm \) 2 %, 56 \(\pm \) 2 %, and 46 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vivo), which were more potent vs. TMV than was ribavirin (36 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vitro; 37 \(\pm \) 2, 41 \(\pm \) 2, and 38 \(\pm \) 1 % at 500 \(\upmu \)g/mL in vivo). The size of the fused ring has important effects on anti-TMV potency, which may be ascribed to conformational differences. The X-ray structures of I-1, I-6, II-8, and III show differing conformational preferences. The most potent compounds can be used as leads for further optimization as antiphytoviral agents.     

A practical multi-step synthesis of ethyl N-functionalized $$\varvec{\upbeta }$$-amino benzimidazole acrylate derivatives as promising cytotoxic agents

A series of 16 new ethyl \(\upbeta \)-amino benzimidazole acrylate derivatives 12(a–p) with a (2E)-s-cis/trans conformation and bearing two points of diversity was designed and synthesized by using a multi-step strategy (reductive amination, deprotection in acidic media and transamination) in moderate to good yields from ethyl 3-dimethylamino-2-(1H-benzimidazol-2-yl)acrylate (5) and monosubstituted N-Boc diamines (7a,7b) as starting building blocks. Products 12 were evaluated for their in vitro cytotoxic potential against six selected human cell lines (Huh7-D12, Caco2, MDA-MB231, HCT116, PC3 and NCI-H727). Compounds 12a, 12e and 12l exhibited selective and micromolar antitumor activities against Huh7-D12 and Caco2 cell lines.