2,098 research outputs found
Magnetic properties of GdZn (T = Fe, Co) investigated by X-ray diffraction and spectroscopy
We investigate the magnetic and electronic properties of the GdZn
( = Fe and Co) compounds using X-ray resonant magnetic scattering (XRMS),
X-ray absorption near-edge structure (XANES) and X-ray magnetic circular
dichroism (XMCD) techniques. The XRMS measurements reveal that the
GdCoZn compound has a commensurate antiferromagnetic spin structure
with a magnetic propagation vector =
below the N\'eel temperature ( 5.7 K). Only the Gd ions carry a magnetic moment forming an
antiferromagnetic structure with magnetic representation . For the
ferromagnetic GdFeZn compound, an extensive investigation was
performed at low temperature and under magnetic field using XANES and XMCD
techniques. A strong XMCD signal of about 12.5 and 9.7 is observed
below the Curie temperature ( 85 K) at the Gd- and edges,
respectively. In addition, a small magnetic signal of about 0.06 of the
jump is recorded at the Zn -edge suggesting that the Zn 4 states are spin
polarized by the Gd 5 extended orbitals
Valorization of sewage sludge for volatile fatty acids production and role of microbiome on acidogenic fermentation
This work explored the production of volatile fatty acids (VFA) through the anaerobic digestion of sewage sludge
(SS). The first experiment took place at batch scale to evaluate the combined effect of using a thermal pre-
treatment (120 \ub0C, 15 min) and different Substrate/Inoculum ratios (S/I) (1, 2, 4 and 6 g VS substrate/g VS
inoculum) on the acidogenic potential of the SS. The results showed that the thermal pre-treatment influenced
positively the degree of acidification of the SS at low S/I ratios, reaching maximum of 45%. Afterwards, a
continuous lab-scale experiment, was set-up to study two ranges of organic loading rates (OLR): 1300\u20131600 mg
COD L 121 d 121 and 2400\u20133500 mg COD L 121 d 121 . The highest degree of acidification (22%) was achieved at the
lowest OLR. Analysis of the microbial community in the reactor revealed that OTUs most abundant present genes
related with amino acids and carbohydrates fermentation being crucial for VFA production
Aneurysmal Degeneration of the Brachial Artery after Vascular Access Creation: Surgical Treatment Results
True peripheral artery aneurysms proximal to a longstanding arteriovenous fistula is a well-recognized complication. Late aneurysmal degeneration is rare. This study analyzed the characteristics, therapeutic options, and outcomes of true donor brachial artery aneurysms (DBAA) after arteriovenous fistula (AVF) for hemodialysis. We retrospectively collected the data of patients with DBAA after AVF creation, surgically repaired between January 2001 and September 2015. We excluded patients with pseudoaneurysms, anastomotic aneurysms, and infected aneurysms. We recorded patient's demographics, type of access, aneurysm characteristics, symptoms, treatment, and follow-up. Ten patients were treated for aneurysmal degeneration of the brachial artery. Average aneurysm diameter was 37.5 mm. All cases had, at least, one previous distal AVF, ligated or thrombosed, at the time of diagnosis. The first access was created in mean 137 months before the diagnosis of DBAA. Nine patients had previous medical history of renal transplant and were under immunosuppressive therapy. All patients were symptomatic at the time of diagnosis. In all cases, the treatment was aneurysmectomy followed by interposition bypass. One patient developed a postoperative hematoma with the need of surgical drainage. At 50 months of follow-up, one patient was submitted to percutaneous angioplasty due to an anastomotic stenosis. No other complications occurred during the entire follow-up period (mean: 69 months). The pathogenesis underlying DBAA remains unclear. Increased blood flow after AVF creation, immunosuppressive therapy, and ligation/thrombosis of the AVF may contribute to aneurysm formation. Surgical treatment by aneurysmectomy and bypass, with autogenous conducts, is a safe and effective option.info:eu-repo/semantics/publishedVersio
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