Sm doped Ba–Co hexaferrite with composition BaCo0.8SmxFe(11.2−x) O19 (x=0.2, 0.4 and 0.6) were prepared via a citrate precursor method. After appropriate heat treatments, the ferrite samples were ...characterised by using different measurement techniques. X-ray diffraction (XRD) confirmed the formation of M phase with an average crystallite size of 35–45nm. Observed tensile strain leads to the elongation of Ba–Co grains and was calculated using Williamson Hall plot. Surface morphology of these samples was studied by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). σ–H loops of these samples were measured at room temperature up to an applied field of 22,000Oe using vibrating sample magnetometry (VSM). With an increase in concentration of Sm ions in Ba–Co lattice, specific saturation magnetisation (σs), coercivity (Hc) and retentivity (σr) values were found to decrease. At x=0.2, excellent values of Hc (2690.20Oe) and squareness ratio (SQR=0.5619) were simultaneously found. These parameters make this material a promising candidate for the applications such as high density magnetic recording and enhanced memory storage.
In this 10-month, crossover, double-blind study of 16 patients with severe, refractory obsessive–compulsive disorder (OCD), stimulation of the subthalamic nucleus reduced the symptoms of OCD. Eleven ...patients had serious adverse events, including one intracerebral hemorrhage and two infections requiring electrode removal.
Stimulation of the subthalamic nucleus reduced the symptoms of OCD in 16 patients; however, 11 patients had serious adverse events.
Severe obsessive–compulsive disorder (OCD) is characterized by intrusive, anxious thoughts and repetitive, ritualized behaviors. It is one of the most disabling of the chronic psychiatric disorders and has considerable repercussions on family relationships, social life, and the ability to function at work.
1
The current treatment of OCD consists of a combination of serotonin-reuptake inhibitors and cognitive–behavioral therapy; with this treatment, however, 25 to 40% of patients have persistent symptoms and lasting functional repercussions.
2
In the hope of reducing the disability and debilitation of patients whose OCD is highly refractory, ablative neurosurgical stereotactic treatments have been attempted, but the efficacy of . . .
This paper describes the first electromagnetic characterization of a self-biased circulator in molded interconnect device (MID) technology. The circulator was designed using a 3D full-wave commercial ...simulator. It consists of microstrip access lines connected to a Y-junction in Substrate Integrated Waveguide (SIW) technology. Unlike classical technologies, the SIW Y-junction was not fabricated using metallic vias but by a Laser Direct Structuring (LDS) technique. A molded Cyclo-Olefin Polymer (COP) was used as a substrate and 3D metallized. The microwave properties of LDS-compatible COP are not well known so we investigated them through the use of cavity-perturbation and rectangular waveguide characterization methods. The device was then machined to insert a pre-oriented strontium hexaferrite puck doped with cobalt and lanthanum (Sr0,7La0,3Fe11,7Co0,3O19). The characteristics of the MID circulator were assessed between 28 and 32GHz. Without magnets, insertion losses of 3.32dB were measured at 30.7GHz. At the same frequency, an isolation level of 13.89dB and return losses of 19.89dB were observed. These measurements demonstrate for the first time the high potential of MID technology for the realization of low-cost non-reciprocal devices.
•Molded Interconnect Device technology was used to realize a self-biased circulator.•This is the first demonstration of a non-reciprocal effect in MID technology.•Pre-oriented hexaferrites enable a self-biased circulation.•(La,Co)0.3-SrM hexaferrite cylinder shows a remanence to saturation ratio of 90%.•The measured self-biased circulator shows insertion losses of 3.3 dB and an isolation level of 13.9dB at 30.7GHz.
A series of Co
2+
substituted Li
0.5
Co
x
Fe
2.5−x
O
4
(x = 0.1, 0.3, 0.5) has been prepared by a citrate precursor method. The distribution of cations on A-site and B-site was studied by X-ray ...Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Mössbauer Spectroscopy. XRD confirmed the formation of ordered α-phase with prominent peaks at (220), (311), (400), (422), (511), (440). SEM and TEM confirmed the homogeneous formation of cubic phase with an average crystallite size of 50 nm. From FTIR studies, the bands at 603.78, 606.14 and 610.08 cm
−1
confirmed the formation of Fe
3+
–O
2−
bond at tetrahedral (A-site), whereas bands at 477.25, 474.84 and 471.69 cm
−1
confirmed the formation of Fe
3+
–O
2−
bond at octahedral site (B-site); shifting in frequency was observed with an increased amount of cobalt doping. Further, Raman spectra revealed the distribution of cations at tetrahedral and octahedral site by means of modes A
1g
, T
2g
, E
g
. Mössbauer spectra with two magnetic sextets confirmed two different environments of Fe
3+
ions. With an increase in cobalt doping, the crystallite size was observed to increase and hence an increase in relative area B/A ratio confirming the occupancy of Co
2+
at B-site. The temperature dependence of DC resistivity was found to decrease with an increase in temperature. With an increase in cobalt substitution, DC resistivity was observed to increase from 2.32 × 10
6
to 3.46 × 10
7
Ω cm. A decrease in activation energy is noticed in the present investigation and this observed semiconducting behavior makes these nanomaterials suitable in NTC (negative temperature coefficient) devices. These observations were explained on various models and theories.
This paper dealt with the determination-at room temperature-of two contributions to the total anisotropy field HA of soft ferrite-based composite materials. These contributions (H K and H σ ) came ...from the magnetocrystalline anisotropy and from the magnetoelasticity, respectively. The values of HA were determined through microwave measurements of the permeability ferromagnetic resonance method (FMR) and also through a static method singular point detection method (SPD). The contributions of HK and Hσ were experimentally distinguished and separated and their values interpreted. The results obtained from these two methods compare well. The values of HK are consistent with the published data. The ability of the SPD method to determine induced anisotropy fields in materials textured by external stress is highlighted. The FMR method appeared to be more precise in measuring H A , H K , and H σ , in reason of some inaccuracies coming from the sensitivity of the SPD method to demagnetizing effects. However, and unlike the FMR method, the SPD method is believed to be applicable to further temperature measurements of anisotropy fields.
•We proposed a simple and affordable new process to realize staking of BaM ferrite platelets.•The coprecipitation method is used to synthesis BaM particles.•The influences of the nature and of the ...excess in precipitating agent are highlighted.•The squarness ratio is MR/MS = 0.88 and the coercive field is HC = 215 kA/m.•The obtained material is suitable for self-biased applications in the microwave domain.
An efficient and inexpensive process is presented that produces highly oriented bulk compacts made of BaM particles. Barium hexaferrite particles (BaM, nominal composition BaFe11O19) were prepared by a chemical coprecipitation method, using different rates and types of precipitating agents (NaOH and Na2CO3). It was demonstrated that when a large excess of Na2CO3 is used, a noteworthy packing of hexagonal BaM platelets is obtained, after mechanical compaction and firing at moderate temperature (1140 °C), without including any more steps than those required for a conventional sintering process. The hysteresis loop displays a very competitive squareness of 0.88 (normalized remanent magnetization) and a coercivity of 215 kA/m, which make this BaM bulk ferrite suitable for self-biased applications.
The main issue to tune controlled devices by the application of a DC magnetic field comes up against the high value of the field’s intensity required for their implementation. This work presents an ...implementation of magneto-dielectric materials (MDM) specifically manufactured for their integration in antenna devices operating in VHF band. The twofold objective is: (i) reduction in antenna size, (ii) frequency tuning of the antenna using a low intensity magnetic control. A notable permeability variation of MDM samples is observed when the symmetry of the lines of the control field, with an intensity less than 10 Oe, is consistent with the one of the structures in the magnetic domains. The MDM allows a miniaturization of 20% of an inverted-F antenna (IFA) antenna structure, and an agility of about 2.5% for a control field of 1.5 Oe.
Background
Following the results of randomized controlled trials on levosimendan, French health authorities requested an update of the current use and side-effects of this medication on a national ...scale.
Method
The France-LEVO registry was a prospective observational cohort study reflecting the indications, dosing regimens, and side-effects of levosimendan, as well as patient outcomes over a year.
Results
The patients included (
n
= 602) represented 29.6% of the national yearly use of levosimendan in France. They were treated for cardiogenic shock (
n
= 250, 41.5%), decompensated heart failure (
n
= 127, 21.1%), cardiac surgery-related low cardiac output prophylaxis and/or treatment (
n
= 86, 14.3%), and weaning from veno-arterial extracorporeal membrane oxygenation (
n
= 82, 13.6%). They received 0.18 ± 0.07 µg/kg/min levosimendan over 26 ± 8 h. An initial bolus was administered in 45 patients (7.5%), 103 (17.1%) received repeated infusions, and 461 (76.6%) received inotropes and or vasoactive agents concomitantly. Hypotension was reported in 218 patients (36.2%), atrial fibrillation in 85 (14.1%), and serious adverse events in 17 (2.8%). 136 patients (22.6%) died in hospital, and 26 (4.3%) during the 90-day follow-up.
Conclusions
We observed that levosimendan was used in accordance with recent recommendations by French physicians. Hypotension and atrial fibrillation remained the most frequent side-effects, while serious adverse event potentially attributable to levosimendan were infrequent. The results suggest that this medication was safe and potentially associated with some benefit in the population studied.
Hammertoe deformation is a frequent motive for consultation in forefoot surgery, and proximal interphalangeal joint arthrodesis is a classic treatment for fixed deformation, which tends to be ...achieved more and more thanks to specific implants. This work evaluated and compared clinical improvement, radiologic fusion, and complication rates between dynamic (Difuse®) and static (TinyFix®) implants from Biotech Ortho. A total of 95 patients (110 feet and 166 toes; 97 static and 69 dynamic implants) were included. Mean age was 63.6 (±12.6) years in the dynamic group and 62.3 (±14.01) years in the static group. Epidemiologic and intraoperative radiologic data were collected. Pain, toes deformity, complications, and radiologic findings (bone fusion and osteolysis) were recorded at 4 months postoperatively and at the last follow-up. Mean follow-up was 11.5 (range 4 to 28) months, and the position of the implants was more often satisfying in the dynamic group (p = .01). Fusion rates at 4 months were 67% and 80% in the dynamic and static groups, respectively (p = .05). Radiologic osteolysis occurred more frequently in the dynamic group (p = .05 at 4 months), and pain was still present in 3% in the dynamic group at the last follow-up compared with 7% in the static group. Complication rate was 7% in the dynamic group (implant fractures) and 4% in the static group. Revision was considered more often in the dynamic group (p = .01). The static titanium implant seems superior to the dynamic memory shape implant in Nitinol alloy with regard to fusion (p = .04), complications (p = .03), and revision rates (p = .01). The literature review seems to support the good results of static implants compared with the rest of the available arthrodesis implant solutions.
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