Search results for "Molar"
showing 10 items of 1069 documents
Isolation of Four New CoII/CoIII and NiII Complexes with a Pentadentate Schiff Base Ligand: Syntheses, Structural Descriptions and Magnetic Studies
2011
In this paper we report the temperature and pH dependent syntheses and systematic characterization of four new Co(II)/Co(III) and Ni(II) complexes with a pentadentate Schiff base ligand H(3)L obtained by condensing 1,3,-diaminopropan-2-ol with 2-hydroxyacetophenone in 1:2 molar ratio. The room temperature syntheses involving Co(II) and Ni(II) nitrates and the ligand H(3)L lead to the isolation of the dinuclear species [Co(2)L(2)(H(2)O)] (1), and the mononuclear complex [Ni(LH)] (3), respectively, whereas refluxing at basic pH leads to the tetranuclear complexes, [Co(II)(2)Co(III)(2)L(2)(μ(3)-OMe)(2)(NO(3))(H(2)O)(2)]NO(3)·2(H(2)O) (2), and [Ni(4)L(2)(μ(3)-OMe)(2)(H(2)O)(2)]·2H(2)O (4). 1 is…
Hexanuclear NiII4LnIII2 Complexes with SMM Behavior at Zero Field for Ln = Tb, Dy, Ho
2020
A mononuclear Ni(II) complex, [NiL2]·2H2O, was prepared by the reaction of a N2O2 donor monocondensed Schiff base ligand, 2-((3-aminopropylimino)methyl)-6-methoxyphenol (HL), with NiCl2·6H2O. The reaction of this complex with NiCl2·6H2O and LnCl3·6H2O (Ln = Gd, Tb, Dy, Ho) in a 1:1:1 molar ratio leads to four hexanuclear Ni4Ln2 complexes formulated as [{(NiL)2Gd}2(μ2-Cl)2(μ3-OH)4(OH2)4]Cl4·CH3CN·H2O (1), [{(NiL)2Tb}2(μ2-Cl)2Cl2(μ3-OH)4(OH2)2]Cl2·12H2O (2), [{(NiL)2Dy}2(μ2-Cl)2Cl2(μ3-OH)4(OH2)2]Cl2·16H2O (3), and [{(NiL)2Ho}2(μ2-Cl)2(μ3-OH)4(OH2)4]Cl4·CH3CN·1.8H2O (4). The Ln(III) centers are octacoordinated with a triangular-dodecahedral geometry, and the geometries around the Ni(II) center…
Dichlorovanadium (IV) complexes with salen-type ligands for ethylene polymerization
2008
Vanadium complexes with tetradentate salen-type ligands were first time explored in ethylene polymerizations. The effects of the vanadium complex structure, the alkyl aluminum cocatalysts type (EtAlCl2, Et2AlCl, Et3Al, and MAO), and the polymerization conditions (Al/V molar ratio, temperature) on polyethylene yield were explored. It was found that EtAlCl2 in conjunction with investigated vanadium complexes produced the most efficient catalytic systems. It was shown, moreover, that the structural changes of the tetradentate salen ligand (type of bridge which bond donor nitrogen atoms and type of substituent on aryl rings) affected activity of the catalytic system. The complexes containing li…
Protein diffusion through charged nanopores with different radii at low ionic strength
2014
[EN] The diffusion of two similar molecular weight proteins, bovine serum albumin (BSA) and bovine haemoglobin (BHb), through nanoporous charged membranes with a wide range of pore radii is studied at low ionic strength. The effects of the solution pH and the membrane pore diameter on the pore permeability allow quantifying the electrostatic interaction between the chargedpore and the protein. Because of the large screening Debye length, both surface and bulk diffusion occur simultaneously. By increasing the pore diameter, the permeability tends to the bulk self-diffusion coefficient for each protein. By decreasing the pore diameter, the charges on the pore surface electrostatically hinder …
Conductive polycaprolactone/gelatin/polyaniline nanofibres as functional scaffolds for cardiac tissue regeneration
2022
Abstract The endorsement of functional features such as biocompatibility, mechanical integrity, or electrical conductivity to tissue engineering (TE) scaffolds is essential to stimulate cell adhesion and proliferation. In this study, electrospun nanofibers based on polycaprolactone (PCL) and gelatin (Ge) (ratios 60/40, 50/50, and 40/60), and polyaniline (PAni) particles (0.25, 0.50, and 1.00%wt) were prepared. The time of dissolution in an acid solvent mixture before electrospinning allowed for obtaining nanofibers with controlled features. Changes in the molar mass (Mn from 90·103 to 15·103 g·mol−1), in the crystalline microstructure (Xc from 60 to 25%) and the surface morphology (diameter…
LE IPERNATRIEMIE NELL’ANZIANO
2015
L’pernatremia è caratterizzata da un deficit di acqua corporea totale rispetto al sodio ed è definita da una concentrazione plasmatica superiore a 145 mmol/L. L’ipersodiemia nella popolazione geriatrica è un disturbo comune, associato ad una significativa morbilità e mortalità. Le persone anziane sono predisposte a sviluppare ipernatriemia a causa di modificazioni fisiologiche legate all'età: ad esempio la diminuzione della sete, una ridotta capacità di concentrazione delle urine e la diminuzione del contenuto di acqua corporea totale. I farmaci possono aumentare questa predisposizione. Nelle case di cura e di riposo, l’ipernatremia e la disidratazione sono considerate prevenibili, per cui …
ALTERAZIONI DEL METABOLISMO DEL SODIO NELL’ANZIANO: CASISTICA DI UN REPARTO DI GERIATRIA PER ACUTI
2014
Premessa. Le alterazioni della concentrazione plasmatica del sodio rappresentano gli squilibri elettrolitici più frequenti nei pazienti ospedalizzati e l’incidenza e la prevalenza aumentano con l’età. L’invecchiamento rappresenta un fattore di rischio indipendente e molto significativo per le alterazioni del bilancio del sodio e dell’acqua. Numerosi sono i fattori che cooperano nell’aumentare la suscettibilità dell’anziano a tali squilibri, dipendendo da modificazioni fisiologiche età correlate dei meccanismi che regolano il bilancio idro-salino dell’organismo, dalla progressiva riduzione delle capacità di compenso che caratterizza il fenomeno stesso dell’invecchiamento e dalle comorbilità,…
Diffusiosmessungen an polymeren in lösung mittels tracer-technik
2007
A cell for measuring coefficients of diffusion and self-diffusion by tracer techniques is described. The cell consists of two Teflon disks and is of the rotational shearing type. The amount of polymer is minimal (about 0.1 ml. for both components). Labeled and unlabeled fractionated polymethacrylate of identical molecular weight distribution was used to determine diffusion coefficients in benzene and toluene. The classical optical measurement is impossible, for these solvents exhibit a refraction index very close to that of polymethacrylate. In acetone, where optical as well as tracer techniques are applicable, the measured diffusion coefficients of the two methods are in good agreement. Al…
Effect of surface treatment with sandblasting and Er,Cr:YSGG laser on bonding of stainless steel orthodontic brackets to silver amalgam
2011
Objectives: Satisfactory bonding of orthodontic attachments to amalgam is a challenge for orthodontists. The aim of this in vitro study was to compare the shear bond strength of stainless steel orthodontic brackets to silver amalgam treated with sandblasting and Er,Cr:YSGG laser. Study Design: Fifty-four amalgam discs were prepared, polished and divided into three groups: In group 1 (the control group) the premolar brackets were bonded using Panavia F resin cement without any surface treatment; in groups 2 and 3, the specimens were subjected to sandblasting and Er,Cr:YSGG laser respectively, before bracket bonding. After immersing in distilled water at 37°C for 24 hours, all the specimens w…
Response of yeast cells to high glucose involves molecular and physiological differences when compared to other osmostress conditions.
2015
Yeast cells can be affected by several causes of osmotic stress, such as high salt, sorbitol or glucose concentrations. The last condition is particularly interesting during natural processes where this microorganism participates. Response to osmostress requires the HOG (High Osmolarity Glycerol) pathway and several transcription factors, including Hot1, which plays a key role in high glucose concentrations. In this work, we describe how the yeast response to osmotic stress shows differences in accordance with the stress agent responsible for it. Compared with other conditions, under high glucose stress, delocalization of MAPK (Mitogen-Activated Protein Kinase) Hog1 is slower, induction of …