Study of implementation of the Flipped Classroom methodology (Just In Time Teaching) in the Inorganic Materials elective course of the Chemistry Degree at University of Barcelona

The Flipped Classroom (FC) strategy was implemented in an elective course of the Chemistry Degree at UB under its Just In Time Teaching approach. The methodology includes a self-studying activity, an assessment of students' initial level, the on-site FC session, and a verification of their achievements. The results evidenced some deficiencies in the assessment of student's achievements. Nevertheless, students highly appreciated the methodology, which helped them to develop self-learning skills

Tm(III) complexes undergoing slow relaxation of magnetization: exchange coupling and aging effects

The present study focuses on the dynamical magnetic behaviour of exchange coupled 3d-4f complexes containing the scarcely considered non Kramers Tm3+ center, the 3d metal ions being either the low-spin Fe3+ (1) or the diamagnetic Co3+ (2) ion. Both complexes display field-dependent slow relaxation of magnetization. The field and temperature dependences of the relaxation rate provided indication of relevant contributions from quantum tunnelling, direct and Raman processes, with only minor effects from exchange coupling interactions. Furthermore, aged sample of 2 exhibited additional relaxation process, possibly due to solvent loss, highlighting the importance of a careful consideration of this factor when analysing the magnetization dynamics in solvated systems

Multiple Magnetization Reversal Channels Observed in a 3d-4f Single Molecule Magnet

The present study discusses the magnetic dynamics of a previously reported cyanide bridged 3d-4f dinuclear DyIIICoIII complex. Following the axial anisotropy suggested by previous Electron Paramagnetic Resonance spectroscopy (EPR) analysis, the complex turned out to show slow relaxation of the magnetization at cryogenic temperature, and this was studied in different temperature and field regimes. The existence of multichannel relaxation pathways that reverse the magnetization was clearly disclosed: a tentative analysis suggested that these channels can be triggered and controlled as a function of applied static magnetic field and temperature. Persistent evidence of a temperature independent process even at higher fields, attributable to quantum tunneling, is discussed, while the temperature dependent dynamics is apparently governed by an Orbach process. The broad distribution of relaxation rates evidenced by the ac susceptibility measurements suggest a relevant role of the intermolecular interactions in this system

An anomaly in the number of secondary feathers in the Reed Bunting (Emberiza schoeniclus)

L'1.02.92 es va capturar un repicatalons a Canal Vell, Deltebre (Tarragona) que tenia una secundària extra a l'ala dreta. Aquesta ploma estava molt desgastada i sobresortia entre la cinquena i sisena secundària. L'explicació més probable de la presència d'aquesta ploma és que es tractava d'una ploma "fora de lloc" produïda durant el desenvolupament juvenil sense la punta de la beina de la ploma de la següent generació en la base del calamus

Trinuclear heterometallic CuII-MnII complexes of a salen type Schiff base ligand: anion dependent variation of phenoxido bridging angles and magnetic coupling

Five new trinuclear heterometallic CuII-MnII complexes [(CuL)2Mn(O2CPh)2] (1), [(CuL)2Mn(N3)2] (2), [(CuL)2Mn(NCO)2] (3), [(CuL)2Mn(NO3)2] (4) and [(CuL)2Mn(Sal)2]∙CH2Cl2 (5) have been synthesized with the di-Schiff base ligand H2L (where, H2L= N,N'-bis(salicylidene)-1,3-propanediamine and Sal= salicylate). These complexes with different anionic co-ligands have been synthesized to attain a large variation in phenoxido bridging angles and to investigate its consequence on magnetic properties. Single crystal X-ray diffraction analyses reveal that complexes 1, 2, 4 and 5 are linear, whereas 3 has an angular geometry. Variable temperature magnetic susceptibility measurements suggest that all five complexes possess an overall antiferromagnetic interaction between CuII and MnII ions, which results in a final ferrimagnetic ground state with spin 3/2 in the CuII-MnII-CuII trinuclear structure. The weakest antiferromagnetic interaction (JCu-Mn= -7.0 cm-1) is observed for 2 having the lowest value of the Cu-O-Mn angle (92.0°), while the strongest antiferromagnetic interaction (JCu-Mn= -26.5 cm-1) is observed for 3 having the largest Cu-O-Mn angle (101.4°). Complexes 1, 4 and 5 show an average Cu-O-Mn angles of 98.2°, 97.6° and 97.7°, respectively, that lead to intermediate antiferromagnetic interactions (JCu-Mn = -9.6, -9.7, -9.3 cm-1 respectively)

Structural and magnetic characterization of three tetranuclear Cu(II) complexes with face-sharing-dicubane/double-open-cubane like core framework

Three novel tetranuclear copper(II) complexes namely [Cu4(L1)4]∙(dmf) (1), [Cu4(L1)4] (2) and [Cu4(L2)2(HL2)2(H2O)2]∙2(ClO4)∙6(H2O) (3) (H2L1, (E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol; H2L2, (E)-2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol)) were synthesised from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligands. The structural determination reveals that complex 1 crystallizes in the monoclinic system with space group C2/c, whereas both the complexes 2 and 3 crystallize in the triclinic system with space group P-1. Complexes 1 and 2 possess face-sharing dicubane core, on the other hand complex 3 has double open cubane core structure. The copper(II) ions in the cubane core are in distorted square planar geometries, and weak π¿π and C-H¿π interactions lead to formation of a 2D supramolecular architecture for complexes 1 and 2. At room temperature complexes 1, 2 and 3, exhibit fluorescence with a quantum yield (Φs) of 0.47, 0.49 and 0.38, respectively. Variable temperature magnetic susceptibility measurements in the range 2-300 K indicate an overall weak antiferromagnetic exchange coupling in all complexes. The PHI program was used to study their magnetic behaviour. In agreement with their face-sharing dicubane structure, a Hamiltonian of the type H = - J1(S1S2+S1S2'+S1'S2+S1'S2') - J2S1S1', where S1 = S1' = S2 = S2' = SCu = 1/2, was used for studying complexes 1 and 2. Simulations performed suggest magnetic exchange constants with values close to J1 = -20 cm-1 and J2 = 0 cm-1 for these complexes. On the other hand, the spin Hamiltonian H = - J1(S1S4+S2S3) - J2(S1S3+S2S4) - J3S1S2, where S1 = S2 = S3 = S4 = SCu = 1/2, was used to study the magnetic behaviour of the double open cubane core of complex 3 and a good agreement between the experimental and simulated results was found by using the parameters g1 = g2 = 2.20, g3 = g4 = 2.18, J1 = -36 cm-1, J2 = -44 cm-1 and J3 = 0 cm-1

Double mu(2)-(phenoxido)-bridged dinuclear and polynuclear nickel(II) complexes: magnetic properties and DNA/protein interaction

One dinuclear and one 1D polymeric nickel(II) complex, namely {[Ni2(HL)2(pa)2(H2O)2]·DMF} (1) and {[Ni2(HL)2(ppda)(H2O)2]·DMF·H2O}n (2) (H2L = (E)-2-((1-hydroxybutan-2-ylimino)methyl)phenol, pa = 3-phenylacrylate, ppda = p-phenylenediacrylate) have been synthesized and characterized by X-ray single crystal structure determination. Complex 1 is double phenoxo-bridged dinuclear Ni(II) complex, whereas complex 2 is a 1D polynuclear chain where double phenoxo-bridged dinuclear units are connected through bridging ppda ligands. The variable temperature magnetic behavior of the complexes was studied using the Hamiltonian H = −JS1S2, S1 = S2 = SNi and confirms the presence of an overall antiferromagnetic interaction in both complexes. Good agreement between the experimental and simulated curves were found using the parameters: gNi = 2.15, DNi = 4.0 cm−1 and JNi-Ni = −0.60 cm−1 for 1, and gNi = 2.15, DNi = 4.8 cm−1 and JNi-Ni = −3 cm−1 for 2. The interactions of the complexes with CT-DNA were investigated using UV-Vis absorption and fluorescence spectroscopic methods and they show that both the complexes interact with CT-DNA. The intrinsic binding constants values for interaction with CT-DNA are 3.9(±0.10) × 105 and 3.43(±0.09) × 105 M−1 for 1 and 2, respectively. The interactions of the complexes with bovine serum albumins (BSA) and human serum albumins (HSA) were also studied using electronic absorption and fluorescence spectroscopic techniques and the results show that both complexes interact with the serum albumins via a ground state association process

DNA/protein binding and magnetic properties of a 1D Cu(II) complex containing fumarate and tridentate Schiff base ligands

ID copper(II) complex, [Cu2(L)2(fum)]∙H2O}n (1) has been synthesized using fumarate (fum2-) and a Schiff base (HL), derived from the condensation reaction of 2-amino-1-butanol and salicyldehyde. Complex 1 has been characterized by X-ray crystal structure, FT-IR, electronic absorption and fluorescence spectroscopic methods. The structural determination reveals that complex 1 crystallizes in the monoclinic system with space group P21/n and form 1D polymeric chain, built by bridging fum. Weak π¿π and C-H¿π interactions in 1, lead to a 3D supramolecular architecture. Complex 1 exhibits fluorescence at room temperature with a quantum yield (Φs) of 0.257. The interactions of complex 1 with bovine serum albumin (BSA) and human serum albumin (HSA) were studied using electronic absorption and fluorescence spectroscopic techniques and the analysis shows that complex 1 interaction with BSA / HSA occurs mainly with ground state association process. Calculated values of apparent association constants are 1.34 × 104 M-1 and 1.81 × 104 M-1 for BSA and HAS, respectively, at 300 K. The number of binding sites and binding constants were calculated using double logarithm regression equation. The interaction of complex 1 with the calf thymus DNA (CT-DNA) was also investigated using electronic absorption and fluorescence spectroscopic methods. The results show that complex 1 has binding affinity to CT-DNA in the order of 2.96×105 M-1. Low temperature magnetic measurements reveal existence of antiferromagnetic interaction in complex 1. The magnetic data have been fitted considering complex 1 as a pseudo-dinuclear system, with the two copper(II) atoms bridged by two carboxylate oxygen atoms, since the coupling through long fum bridge is almost nil. The best-fit parameters obtained with this model are J = - 60 cm-1, gCu = 2.20

Immune Response to Newcastle Disease Virus Vaccination in a Wild Passerine

We studied the immune response of wild House Sparrows (Passer domesticus) experimentally challenged with different doses of inactivated Newcastle disease virus (NDV) vaccine. We evaluated within-individual cell-mediated and humoral responses in birds kept in outdoor aviaries, over a 6-wk period. Nonbreeding adult House Sparrows developed a significant humoral response to NDV experimental vaccination within 1 wk postchallenge, as measured by hemagglutination inhibition assay; values increased until week 4 and persisted until week 6. Differences among treatments appeared by week 1, with individuals challenged with the highest dose (0.2 mL) eliciting a higher humoral response than the rest (n = 18). By week 4, all individuals vaccinated displayed an increased humoral response, with individuals challenged with the highest dose remaining significantly above responses of individuals vaccinated with the middle dose (0.1 mL, n = 14), but not the lowest dose (0.05 mL, n = 15). The middle and lowest dose responded similarly and significantly different from controls (n = 23). Differences persisted through week 6 postchallenge. Cell-mediated responses were independent of the experimental treatment. All individuals experienced a rise in granulocyte concentration, whereas lymphocyte and monocyte concentrations decreased, most likely as a result of captivity. Adult wild House Sparrows immunochallenged with inactivated NDV vaccine developed a specific humoral response, highlighting the utility of this technique in immunologic and evolutionary ecology studies in wild birds.Peer reviewe

Two new μ2-(1,1-azido) and μ2-(1,1-phenoxido)-bridged dinuclear nickel(II) complexes: Syntheses, single-crystal structures and magnetic studies

Two dinuclear azido bridged Ni(II) complexes [Ni2(HL1)2(N3)(C8H7O3)]∙(H2O) (1) and [Ni2(L2)2(N3)2(H2O)](2) [H2L1 and HL2 are Schiff bases, obtained from the condensation of 2-hydroxy-3-methoxy-benzaldehyde with 2-amino-2-methyl-1-propanol and N,N-diethylethylene diammine, respectively; C8H7O3 = 3-methoxy-2-oxo-benzaldehyde] have been synthesized and their crystal structures have been determined. Complex 1, C32H39N5Ni2O10, crystallizes in a triclinic system, space group P-1 with a = 10.0846(6), b = 12.5179(7), c = 14.1176(8) Å, α = 74.3873(7), β =83.9553(7), γ = 83.1921(7) º and Z = 2; complex 2, C28H44N10Ni2O5 , crystallizes in an orthorhombic system, space group Pbca with a = 12.4197(1), b = 21.4737(4), c = 24.4569(5) Å, and Z = 8. X-ray single crystal structure determination reveals that both the complexes are dinuclear with μ2-(1,1-azido) and μ2-(penoxido) bridges. Variable temperature magnetic studies indicate overall ferromagnetic interaction between nickel(II) centers in both the complexes. The experimental magnetic data of the complexes were fitted using PHI program and isotropic Hamiltonian H = -JS1S2, where S1 = S2 = SNi. A zero-field splitting parameter (D) and intermolecular interaction term (zJ') were also considered in the model and a good agreement between experimental and simulated curves were found by using the following parameters: gNi= 2.13, DNi= 5.83 cm-1, JNi-Ni = 14.61 cm-1 and zJ' = -0.1 cm-1 for 1, and gNi= 2.15, DNi= 2.33 cm-1, JNi-Ni = 13.09 cm-1and zJ' = -0.07 cm-1 for 2