Search

The effect was investigated of nitrogen impurities on the morphology and magnetoresistance properties of Co-N and Ni-N thin films. The films were electroplated onto aluminum substrates, at room temperature, using the same electrodeposition parameters (pH = 3 and temperature 30 C) for all experiments. The films were compared with similar samples obtained in the absences of nitrogen impurities. Scanning electron microscopy, X-ray photoelectron spectroscopy, and magnetoresistance measurements were utilized to characterize the studied films. The presence of nitrogen in the electrodeposited films have a significant influence on the morphology and magnetoresistance of electrodeposited films. Incorporation of a small amount of nitrogen into electrodeposited films increases the magnetoresistance up to 0.21 % for Co-N thin films and respectively 0.65 % in the case of Ni-N films. We suppose that the shape of the magnetoresistance curves is influenced by the interaction between the magnetic moment of the neighboring Co or Ni grains (with ferromagnetic behavior) separated by the nonmagnetic regions. Interfacial complexities of a ferromagnetic metal/oxide interface in studied thin films could force the interfacial spins to align ferromagnetically or antiferromagnetically. They could be useful for technological applications in electronics. [ABSTRACT FROM AUTHOR]

Background. The modifications of blood pressure and lipid metabolism, the decrease of heart contractility and the increase of systemic vascular resistance that accompany hypothyroidism are caused by the decreased action of thyroid hormones. Objective. The purpose of this study is to evaluate, using echocardiography, the changes of the heart functional parameters in patients with untreated thyroid dysfunctions. Pacients and Methods. Study group included 348 patients for an evaluation of cardiovascular and thyroid status. The control of the thyroid condition was conducted using measurements of the FT3, FT4 and TSH levels, echocardiographic measurements defining the parameters of the function of the left ventricle. Results. The study group was divided into subclinical hypothyroidism (SH, 75 cases), overt hypothyroidism (OH, 123 patients) and normal thyroid function (C, 150 patients). TSH values decreased (from 5.8±15 mUI/L to 2.28±0.63 mUI/L in SH and from 20.23±17.33 mUI/L to 4.24±0.24 mUI/L in OH) after one year of treatment while fT4 and fT3 increased. The parameters obtained revealed significant decreases of the E/A ratio in both groups with hypothyroidism. The isovolumetric relaxation time was significantly higher in SH and OH as compared to the control group (C: 112.50±35.45 msec, SH: 118.75±16.52 msec p<0.05, OH: 130±41.83 msec p<0.001). In addition, the tissue Doppler revealed significant decreases of the E'/A' ratio, measured septally and laterally in the group with overt and subclinical hypothyroidism. Conclusion. In hypothyroidism the systolic and predominantly diastolic function of the left ventricle are impaired. These dysfunctions are reversible under L-T4 substitutive treatment. [ABSTRACT FROM AUTHOR]

The surface morphology and magnetic properties of Co-Ni-N thin films electrodeposited under an external magnetic field were investigated. The films were electroplated on Al substrates using the same electrodeposition parameters (temperature and pH) for all experiments, with an external magnetic field of 107 Oe applied to the cathode surface. The films were compared with similar samples obtained in the absences of magnetic field. The magneto-induced modifications in the Co-Ni-N morphology can be explained by the specific local convection of ions at the interface cathode-electrolyte, which promotes changes both in the electrical charge of the double layer and in the thickness of the diffusion layer. From the magnetic measurements, we found that the coercivity varied between H=(14÷27) kA/m depending on the direction of the applied magnetic field and on the sodium nitrate content in the plating bath. It was observed that an induced anisotropy appeared in the Co-Ni-N films due to the preferential orientation of the easy axis of magnetization in the magnetic field direction. In addition, the Co-Ni-N alloy films showed good magnetic property, which is considered that not only the smaller grain size of the films, but also more uniform surface of the films than that deposited in absence of applied magnetic field. [ABSTRACT FROM AUTHOR]

The effect of nitrogen addition on the morphology, magnetic anisotropy, and magnetoresistance properties of Co-Ni-N granular thin films were investigated. The films were grown by electrodeposition onto aluminum substrates at room temperature. By a complex process of cationic catalysis occurring at the cathode/electrolyte interface, nitrogen is adsorbed in the Co-Ni film. Finally, a granular film grows by a tridimensional progressive nucleation mechanism. The nature of the grains and of the interface between them influences exchange interactions between grains, which play an important role in determining the magnetic anisotropy. From the magnetic measurements, we found that the magnetic anisotropy constant varied in the range K=(−21.5÷36.6)×10 J⋅m and the coercivity varied between H=(13÷67) kA⋅m depending on the sodium nitrate content in the plating bath. The Co-Ni-N granular thin films display large values (∼160%) of magnetoresistance. These large values of magnetoresistance make such structures attractive for applications as sensitive magnetic field sensors. [ABSTRACT FROM AUTHOR]

Abstract: A series of Co, Ni and Co–Ni granular thin films with variable nitrogen content in the range 0–16at.% N were prepared by electrodeposition onto aluminum substrate. The nitrogen content was varied in order to analyze its influence on the magnetoresistance. The morphology, structure and magnetic properties of electrodeposited Co, Ni and Co–Ni granular thin films were also studied as a function of the nitrogen content. The magnetoresistance (MR) ratio of Co–Ni–N granular films initially increased and then decreased when increasing the nitrogen content. The films exhibit a granular morphology, with rich in nitrogen frontiers between grains and some un-deposited sites on the aluminum substrate, which easily oxidize even during the process of preparation, favoring the spin tunneling transport. We obtained tunneling magnetoresistance (TMR) effect in the Co–Ni–N granular thin films in the range 3–159%; this large effect obtained in Co–Ni–N granular thin films makes them suitable for applications in electronics. [Copyright &y& Elsevier]

Abstract: We present in this paper several results concerning the preparation by means of electrolysis and characterization of Co–Ni–Mo thin films. Co–Ni–Mo thin films with different molybdenum content in the range 0–25at% Mo were prepared from a complex solution containing ions of Co, Ni and Mo, using galvanostatic control, on aluminum substrates. The effects of applied current density on the morphology, magnetic, magnetoresistance, and optical properties of the electrodeposited Co–Ni–Mo films were investigated. The applied current density significantly influenced the film composition and their magnetic properties. The increase of molybdenum content in Co–Ni films (up to 25at% Mo) enhances the resistivity, but it reduces the magnetoresistance effect. We report the first observation of magnetoresistance as high as 8% in Co–Ni–Mo thin films. [Copyright &y& Elsevier]

Abstract: In this work, we report on experimental investigation of the influence of nitrogen addition on magnetic and transport properties of Co–Ni granular films with different nitrogen content correlated with the surface morphology. The granular thin films were electrodeposited on aluminium substrate, from the following base solution: 30g/l CoSO4·7H2O, 50g/l NiSO4·7H2O, 10g/l NiCl2·6H2O, 50g/l Na2SO4·10H2O, 30g/l H3BO3 and 10g/l NaCl. Sodium laurylsulphate (C12H25NaO4S) and sodium saccharine (NaC7H4O3NS·2H2O) were used as additives. As a source for nitrogen inclusion in the films by cationic catalysis, sodium nitrate (NaNO3) was introduced in the electrolyte. The concentration of NaNO3 in electrolytic bath was varied with the aim to control the films nitrogen content. Co–Ni–N/Al granular films display tunneling magnetoresistance (2–160%) effect which could be explained mainly by the elastic spin-dependent scattering of conduction electrons at the interface between magnetic grains (constituted of Co–Ni solid solution) and nonmagnetic regions (rich in N inter-granular frontiers and aluminium oxidized substrate). [Copyright &y& Elsevier]

Clostridial neurotoxins have assumed increasing importance in clinical application. The toxin's light chain component (LC) inhibits synaptic transmission by digesting vesicle-docking proteins without directly altering neuronal health. To study the properties of LC gene expression in the nervous system, an adenoviral vector containing the LC of tetanus toxin (AdLC) was constructed. LC expressed in differentiated neuronal PC12 cells was shown to induce time- and concentration-dependent digestion of mouse brain synaptobrevin in vitro as compared to control transgene products. LC gene expression in the rat lumbar spinal cord disrupted hindlimb sensorimotor function in comparison to control vectors as measured by the Basso-Beattie-Bresnahan (BBB) scale (P<0.001) and rotarod assay (P<0.003). Evoked electromyography (EMG) showed increased stimulus threshold and decreased response current amplitude in LC gene-transferred rats. At the peak of functional impairment, neither neuronal TUNEL staining nor reduced motor neuron density could be detected. Spontaneous functional recovery was observed to parallel the cessation of LC gene expression. These results suggest that light chain gene delivery within the nervous system may provide a nondestructive means for focused neural inhibition to treat a variety of disorders related to excessive synaptic activity, and prove useful for the study of neural circuitry.Gene Therapy (2005) 12, 108-119. doi:10.1038/sj.gt.3302400 Published online 21 October 2004 [ABSTRACT FROM AUTHOR]

This article, published in the journal Thoracic & Cardiovascular Surgeon, examines the acute changes in biventricular intrinsic myocardial function that occur during percutaneous pulmonary valve implantation (PPVI) in patients with right ventricular outflow tract (RVOT) dysfunction. The study involved twenty patients who underwent PPVI, and their biventricular pressure-volume loops were assessed using a conductance catheter technique. The results showed that after PPVI, there was a significant decrease in right ventricular contractility and pulmonary arterial elastance, while left ventricular contractility remained unchanged. The study suggests that further investigation is needed to understand the long-term effects of these response patterns on biventricular remodeling. [Extracted from the article]

Background In young patients with native aortic coarctation (CoA), the management of choice is surgery. However, in re-coarctation (re-CoA) surgery is associated with increased morbidity and even mortality. Some children with native CoA present relative contraindications for surgery. Methods From 2006 to 2017, thirty-four patients (male n  = 20; 59%) from two centres with re-CoA (31) and native CoA (3) were managed by stent implantation with premounted balloon expandable stents. Inclusion criteria were age < 3 years and >1 month, weight < 16 kg. Median age was 6,5 months (min. 1; max. 34 months), median weight 6,2 kg (min. 3,7; max. 16 kg). Thirteen patients (38%) had Re -CoA and hypoplastic left heart syndrome (HLHS). In three patients (9%) the native CoA was stented due to contraindications for surgical treatment. Results All procedures were successful. The median peak invasive systolic pressure gradient declined from 31 mm Hg (max. 118; min. 4) to 0 mm Hg (max. 32; min.-7) ( p  < 0.001). The median minimal diameter of the narrowed segment of aorta increased from 3 mm (max. 6,9; min. 1,0) to 7 mm (max. 11,5; min. 3,5) ( p  < 0.001). There were no serious complications. The median follow-up time was 12,5 months (max. 88; min. 0 month). During this time ten patients (29%) required re-dilatation and two of them re-stenting. Conclusion Percutaneous stent implantation for Re-CoA and in selected patients for native CoA can be performed successfully in very young patients with a good immediate hemodynamical result. However, repeated stent angioplasties and further on interventional ‘opening’ of the stent is necessary to augment the aorta to adult size. [ABSTRACT FROM AUTHOR]

Presents a corrected reprint of an article titled "adenoviral clostridial light chain gene-based synaptic inhibition through neuronal synaptobrevin elimination," published in a previous issue of the periodical "Gene Therapy."

Abstract: In this report we describe some experimental results concerning the preparation by electrodeposition and characterization of Co/Zn multilayer films, a system of special significance because Co and Zn are immiscible in a large range of compositions, permitting an easier adaptation of the sharp interfaces and the magnetic interactions between layers, with a view to obtain technological applications in nano-electronics. We established the working parameters for electrodeposition of multilayer films based on Co and Zn nanoscale layers, using a dual-bath potentiostatic electrodeposition method. The effect of the first electrodeposited layer growth process on the structure and magnetic properties of the multilayer were studied by using two series of multilayers of varying periods, starting with Co or Zn layers, respectively (with the same total thickness of Co layers, namely 50 layers of 5nm thick, but various Zn layer thickness). These properties were also studied as a function of the Zn layer thicknesses (varying between 0.1nm and 5.9nm), for the two series of films. The magnetoresistance (in the current in plane configuration with dc magnetic field applied in the film plane), varied with Zn layer thickness, exhibiting a giant magnetoresistance contribution of about 30% in the case of [Co (5nm)/Zn (2.7nm)]50 films. [Copyright &y& Elsevier]

In this work, we report experimental results concerning the giant magnetoresistance effect and the magnetic properties of [Ni-Fe/Zn/Co-Ni-N/Ni-Mn] spin-valve sandwich electrodeposited on Cu substrate. The attraction of such granular spin valves is that they can be very easily manufactured, with a view to their application as magnetoresistive material in magnetic field sensors. The granular structure is induced both due to the immiscibility of the diamagnetic Zn layer with the ferromagnetic Co-Ni-N, and to the addition of N impurity in the Co-Ni-N layer. The thickness of the Zn diamagnetic interlayer (varying between 3 nm and 13 nm) plays a significant role on the magnitude of the giant magnetoresistance (GMR) effect, and the magnetic behavior is dependent on this parameter. The magnetoresistance measured in current in plane (CIP) and current perpendicular to plane (CPP) configurations, with dc magnetic field applied in the film plane, varied with Zn interlayer thickness, exhibiting a GMR contribution of about 13% (CIP) and 10% (CPP) in the case of [Ni-Fe(140nm)/Zn(3 nm)/Co-Ni-N(150nm)/Ni-Mn(160nm)] granular spin-valve stack. [ABSTRACT FROM AUTHOR]

Especially complicated, renal lithiasis contributes to the general inflammatory syndrome development that interferes with nonspecific, humoral and cellular immune system. The surgical treatment of nephrolithiasis is closely related to drug therapy of urinary infection, one of the reasons being the reduction of the immune status. The work is performed by evaluating the immunological status preoperatively in 58 patients with complicated lithiasis. The analysis of the status in these patients demonstrated that complicated urolithiasis results in significant changes in the immune system, these changes being expressed at the cellular and humoral level of immunity. [ABSTRACT FROM AUTHOR]

The early pathophysiology of diabetic retinopathy and the involvement of neural and vascular malfunction are poorly understood. Glial cells provide structural and metabolic support for retinal neurons and blood vessels, and the cells become reactive in certain injury states. We therefore used the streptozotocin rat model of short-term diabetic retinopathy to study glial reactivity and other glial functions in the retina in the first months after onset of diabetes. With a two-site enzyme-linked immunosorbent assay, we measured the expression of the intermediate filament glial fibrillary acidic protein (GFAP). After 1 month, GFAP was largely unchanged, but within 3 months of the beginning of diabetes, it was markedly induced, by fivefold (P < 0.04). Immunohistochemical staining showed that the GFAP induction occurred both in astrocytes and in Müller cells. Consistent with a glial cell malfunction, the ability of retinas to convert glutamate into glutamine, assayed chromatographically with an isotopic method, was reduced in diabetic rats to 65% of controls (P < 0.01). Furthermore, retinal glutamate, as determined by luminometry, increased by 1.6-fold (P < 0.04) after 3 months of diabetes. Taken together, these findings indicate that glial reactivity and altered glial glutamate metabolism are early pathogenic events that may lead to elevated retinal glutamate during diabetes. These data are the first demonstration of a specific defect in glial cell metabolism in the retina during diabetes. These findings suggest a novel understanding of the mechanism of neural degeneration in the retina during diabetes, involving early and possibly persistent glutamate excitotoxicity. [ABSTRACT FROM AUTHOR]