La bourse aiguë douloureuse est une urgence thérapeutique mettant en jeu le pronostic fonctionnel et vital du testicule. Nous avons étudié l’impact du mode de consultation (centre hospitalier ...universitaire CHU, médecin traitant, centre hospitalier général), de l’éloignement géographique et de la durée de la douleur sur le taux d’orchidectomie dans une population pédiatrique.
Les dossiers des enfants de moins de 15ans pris en charge chirurgicalement pour bourse aiguë douloureuse ont été étudiés rétrospectivement. Les données épidémiologiques, l’existence d’une consultation antérieure à la consultation au CHU, le délai de prise en charge et les données peropératoires ont été recueillies de janvier 2007 à janvier 2010.
Sur 76 enfants, 59 avaient une torsion du cordon spermatique (TCS) avérée et 16 avaient une torsion d’hydatide (1 cas d’orchite). Parmi les 59 enfants souffrant de TCS, l’âge médian était de 13ans (0,18–14,97). Pour 32 (54,2 %) d’entre eux le CHU avait été le centre de premier recours (groupe CHU) et 27 (45,8) (groupe hors CHU) avaient consulté à l’extérieur du CHU. Le trajet médian avait été de 19km (2,5–113) dans le groupe CHU et de 44km (2,5–393) dans le groupe hors CHU (p=0,0072). Le délai médian de consultation avait été de 4,3h (0,5–48) dans le groupe CHU et de 11h (2–48) dans le groupe hors CHU (p=0,6139). Le délai médian de prise en charge (temps entre l’arrivée à l’unité d’accueil des urgences et l’incision au bloc opératoire) avait été de 2,5h, sans différence statistique (p=0,8789) entre les 2 groupes. Le taux d’orchidectomie avait été de 25 % dans le groupe CHU et 14,8 % dans le groupe hors CHU (p=0,5177). Pour les enfants ayant subi une orchidectomie, la durée de la douleur avait toujours été supérieure à 6h et significativement plus importante que chez les enfants dont le testicule avait été conservé (12 1–72 versus 24h 6–48 p=0,0001).
Dans cette série, le taux d’orchidectomie n’était pas dépendant du mode de consultation, mais de la durée de la douleur. La suspicion de TCS doit conduire à une exploration chirurgicale en urgence et cela implique une continuité des soins entre les hôpitaux périphériques et les centres de chirurgie pédiatrique.
Acute scrotal pain is a true surgical emergency as patients presenting with acute scrotal pain may suffer from spermatic cord torsion and gonadal loss. We assessed whether the type of consultation (first consultation in our center or secondary transfer from a peripheral hospital or primary care practice), distance from home to hospital, and duration of pain had an impact on the orchiectomy rate.
We retrospectively reviewed the medical records of all patients under 15years of age suffering from acute scrotal pain who had surgical exploration between January 2007 and January 2010 in our center. Patient demographics, transfer status, time to consultation in our center, time to surgery, operative findings and clinical outcome were reviewed.
Of the 76 patients with acute scrotal pain in whom surgical exploration was performed, 59 had acute spermatic cord torsion, 16 had torsion of the testicular appendage, and 1 had orchitis. In patients with acute spermatic cord torsion, the median age was 13 years (range: 0.18–14.97). In patients with acute spermatic cord torsion, 32 came straight to our center (direct admission group, 54.2%), and 27 (45.8%) came after a prior consultation out of side the center (transfer group). The median journey was 19km (range: 2.5–113) in the direct admission group and 44km (range: 2.5–393) in the transfer group (P=0.0072). The median time between pain onset and consultation at our center was 4.3h (range: 0.5–48) in the direct admission group, and 11h (range: 2–48) in the transfer group (P=0.6139). The median time between admission at our center and surgery was 2.5h, with no difference between the 2 groups (P=0.8789). The orchiectomy rate was 25% in the direct admission group and 14.8% in the transfer group (P=0.5177). In children who underwent orchiectomy, the duration of pain was consistently over 6h. The duration of pain was greater in patients with orchiectomy (12h range: 1–72) than in patients without orchiectomy (12h range: 6–48; P=0.0001).
In this study, the orchiectomy rate depended on the duration of pain but not on transfer status. Acute scrotal pain must lead to surgical exploration as soon as possible, requiring close collaboration between peripheral hospitals, primary care physicians, and referral centers.
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•Nd2Fe17-xSix (x = 0, 0.25 and 0.5) samples have crystallized in the rhombohedral Th2Zn17 type structure (R-3m).•Rietveld refinement on XRD and Mössbauer spectroscopy analysis reveal ...that the Si atoms substitute Fe in the 18h Wyckoff site.•Tc increases with Si content from 331 K to 366 K for x = 0 and x = 0.5 respectively.•Magnetic entropy variation δS decreases with Si content from 3.35 J/kgK for Nd2Fe17 to 2.50 J/kgK for Nd2Fe16.5Si0.5.
Magnetic refrigeration could ultimately allow the replacement of commonly-used industrial coolers or household refrigerators, mainly for its potential great efficiency and ecological factors.
In the search of good magnetocaloric materials, the iron rich Nd2Fe17 intermetallics are regarded as very interesting candidates, due to their significant magnetic properties. To that end, three samples with nominal compositions Nd2Fe17-xSix (x=0,0.25,0.5) were prepared by using an arc furnace, followed by annealing. Structural analysis by Rietveld method on X-ray diffractograms have shown that these alloys crystallize in the rhombohedral Th2Zn17-type structure (Space group R3¯m) and that Fe is being substituted by Si in the 18h Wyckoff position.
Magnetic properties measurements revealed that the Curie temperature increases while the magnetization at saturation diminishes with Si content. The magnetic entropy change ΔSM reached a maximum of 3.35 J/kg.K, 2.77 J/kg K and 2.50 J/kg K for an applied field of 1.5 T for x = 0, 0.25 and 0.5 respectively, pointing to a decrease with Si content. The RCP seems however to receive an extensive boost from the Fe to Si substitution. Mössbauer spectra analysis was also performed, in order to confirm the site 18h as the location of Si atoms in Nd2Fe17-xSix and the magnetization at saturation.
Hypospadias. Surgical management Moscovici, J; Galinier, P; Le Mandat, A
Archives de pédiatrie : organe officiel de la Société française de pédiatrie
16, Številka:
6
Journal Article
•PrCo3−xFex crystallize in rhombohedral PuNi3 type structure (R-3m) for x < 1.•Co substitution by Fe leads to an increase of Tc and Ms for PrCo3−xFex (x ≤ 0.75).•PrCo3−xFex (x ≤ 0.75) has a decrease ...in Hc and anisotropy field with Fe content.•Local environment can be differentiated only with distances of 5.2 Å.•EXAFS: Fe atoms preferably occupy the 18h site in PrCo3−xFex (x < 1). Pr2Co,Fe7 (P6/mmm ) following a direct structure comparison.•18 h site in Pr(Co,Fe)3 (R-3m) is equivalent to the 12 k site in Pr2Co,Fe7 (P6/mmm ).
Nanocrystalline PrCo3-xFex(x⩽1) powder samples were synthesized by high energy milling and subsequent annealing at 1023 K for 30 min. The samples crystallize in the PuNi3-type structure (space group R3¯m) for x<1, confirmed by means of X-ray diffraction. In order to explain the original magnetic properties of these compounds and for the determination of the exchange interaction in theoretical models, the Fe and Co sites and occupancies in the crystallographic structures are required. However, standard XRD can not be used to determine Fe substitution sites, because Co and Fe have too close X-ray atomic scattering factors. Results from neutron diffraction and electronic band structure calculations from our previous works were incomplete or limited. Consequently, we give in this study the characterization of the local structure by X-ray absorption spectroscopy (EXAFS) at the iron K edge. By this method, and if we assume a unique preferential site, it was determined that Fe atoms preferably occupy the 18h site. In order to obtain this result, a coordination sphere around Fe sites of R=5.2 Åhad to be considered in order to find sufficient local differences between the possible sites (18h, 6c and 3b). Furthermore, we provide complementary magnetic properties measurements for PrCo3-xFex (x⩽0.75) such as the coercive field HC, which decreases with iron content from 12 kOe for PrCo3 to 1.5 kOe for PrCo2.25Fe0.75. The magnetization at saturation MS increases from 69 A m2/kg to 89 A m2/kg and the calculated anisotropy field Ha decreases from 15.6 kOe to 11.2 kOe for the same compositions.
Rare-earth-transition-metal intermetallics show very interesting magnetic properties for numerous applications (hard magnetic materials, magnetic refrigeration, ...). This paper is devoted to the ...study of the structural, magnetic, and magnetocaloric effect (MCE) of the intermetallic nanomaterials PrCo
3
, which derives from the PuNi
3
type structure. This system crystallizes into the rhombohedral structure (
R
3
¯
m
space group). PrCo
3
compound exhibits a second-order ferro-paramagnetic transition at around 330 K. This 1:3 system, based on a stacked Pr
2
Co
4
and PrCo
5
units, has a magnetocaloric effect of 1.3 J/kg K at low field. In addition, we demonstrated that the MCE derived from phenomenological and experimental approaches were in agreement.
To substitute NdFeB in many fields, the 1–12 phase is actively studied. That’s the reason why magnetic and magnetocaloric properties of
ThMn
12
have been investigated.
NdFe
11
Ti
and
SmFe
10
V
2
were ...synthesized form bulk materials by arc melting and reduced into a powder by high energy ball milling to obtained a nanometric powder. Then, the powder was annealed in a furnace at different temperatures to crystallize the phase. Rietveld refinement showed that these two alloys crystallized in a
ThMn
12
tetragonal structure which can be described by the
I
4/
mmm
space group. We found
T
C
=
552
K
,
μ
0
H
C
=
1.2
×
10
-
2
T
,
R
C
P
=
42
J.kg
-
1
for
NdFe
11
Ti
and
T
C
=
603
K
,
μ
0
H
C
=
0.4
T
,
R
C
P
=
46
J.kg
-
1
for
SmFe
10
V
2
. It can be assumed that
SmFe
10
V
2
is a hard magnet but not
NdFe
11
Ti
, both could be used as heat-pump.
Nanocrystalline iron-rich intermetallic compounds Sm
2
Fe
17−
x
Si
x
(
x
=
0
,
1
,
1.5
,
2
) were studied by means of X-ray diffraction coupled with magnetic and magnetocaloric properties ...measurements. The mechanically alloyed and annealed compounds were single phase and crystallize into the
R
3
¯
m
Th
2
Zn
17
-type structure. The favorable ratios of the X-ray atomic factor
f
Si
/
f
Fe
allowed the location of the Si atoms in the
R
3
¯
m
structure. The best Rietveld agreement factor assessed for a preferential occupation of Si on the 18
h
site. The Curie temperature was found to increase with Si content
x
from 436 K for
x
= 0 up to 525 K for
x
= 2, whereas the unit-cell parameters, measured with a standard element, were found to decrease with Si content. The random magnetic anisotropy model was used to determine the random anisotropy fields and the local random anisotropy constant. These nanocrystalline Sm
2
Fe
17−
x
Si
x
systems gave good magnetocaloric properties, which however decreased with Si content from 3.29 J/kg K for
x
= 0 down to 2.54 J/kg K for
x
= 2, at low field
μ
0
H
= 1.57 T.
Nickel oxide thin films known as optical active counter electrode in electrochromic devices were grown by Pulsed Laser Deposition (PLD) at room temperature (RT) under a 10
−1
mbar oxygen pressure. ...From intense electrochemical characterizations of as-deposited NiO electrodes in alkaline medium, a mechanism taking into account the three typical steps of their cycling life, namely the
activation period, the
steady state and the
degradation period, is proposed. The reversible color change from transparent to brownish, generally ascribed to the Ni(II)/Ni(III) couple in the literature, was clearly identified to the electrochemically active nickel hydroxide/oxy-hydroxide phases. The reason lies in a spontaneous chemical conversion of NiO into Ni(OH)
2 when the film is immersed in KOH medium. Afterwards, once cycling is performed, there is in competition with the electrochemical process, a self-discharge phenomenon associated to a partial dissolution of the thin-film oxidized phases. This second process becomes predominant on cycling leading to a progressive degradation of the electrochromic performances.
•The nanoparticles cobalt ferrite was synthesized in polyol medium (10nm).•Subsequently, the ferrite is annealed under argon at 873K for different times.•After annealing, we have obtained of ...nanoparticles FeCo.•Their Structural, electronic, and magnetic properties have been presented.•The sample annealed at 873K for 4h exhibits the best Ms (Ms = 235 emu g−1).
Soft-magnetic Fe55Co45 alloy nanoparticles have been successfully synthesized by the polyol reduction process followed by annealing under argon. The diethylene glycol (DEG) was used as solvent and reducing agent simultaneously in this process. The synthesized samples of nanoparticles were annealed at 873K for different times. The alloy formation processes, the evolution of the microstructure, the magnetic properties, and the DOS calculation have been investigated before and after samples annealing. The X-ray diffraction of the synthesized product before annealing shows that a cobalt ferrite is spinel structure of crystallite size of about 10nm. X-ray diffraction analysis of the samples annealed at 873K for different times also shows that of the FeCo alloy has been obtained by reducing the cobalt ferrite. It has been confirmed the formation of a body-centered-cubic (bcc) single phase structure where the wt.% increases with annealing times leading to a pure phase after annealing during 4h. These results are confirmed by transmission electron microscopy study. The saturation magnetization of the Fe–Co alloys increases with annealing time, indicating an increasing homogeneity in composition and the single bcc FeCo phase formation. The highest saturation magnetization of 235emug−1with a low coercivity of 76Oe was obtained for the Fe55Co45nanoparticles annealed during 4h. The local random anisotropy constant KL has been extracted. This work presents also detailed information about total, and atom projected density of state functions, as well as the magnetic moment for different atoms in Fe55Co45 alloys and cobalt ferrite.
