Original implementation of low-temperature SPS for bioactive glass used as a bone biomaterial.

Alkali borated bioactive glasses powders with compositions based on the SiO2-Na2O-CaO-P2O5-x B2O3 system (0 < x < 20 wt%); have been consolidated at low temperature using Spark Plasma Sintering (SPS). Through SPS technique under 50 MPa, it was possible to achieve fully dense and completely amorphous borated glasses at temperatures as low as 420 °C. By increasing the sintering temperature up to 430 °C, the dense samples crystallized which is mostly achieved at higher temperatures. This study reveals that the mechanical properties of these new borated biomaterials are suitable to be used as a promising candidate for repairing defects in non-load-bearing bones as well as for coating on the metallic surface implants to improve the bioactivity process bone/implant. The pressure had a weak effect on the crystallization and densification of the glass compared to the temperature during the powder consolidation by SPS. Moreover, by increasing the boron content, the compressive strength and the elastic modulus of the elaborated glasses decreased for being close to those of the natural.

Study of complex impedance spectroscopic properties of La0.7-x Dy x Sr0.3MnO3 perovskite oxides.

The dysprosium perovskite La0.7-x Dy x Sr0.3MnO3 (x = 0.00 [LSMO] and 0.03 [LDSMO]) compounds were prepared by the sol-gel reaction and characterized by the X-ray diffraction technique. The electrical conductivity and modulus characteristics of the system have been investigated in the temperature and the frequency range 311-356 K and 209-5 × 107 Hz, respectively, by means of impedance spectroscopy. The ac and dc conductivities were studied to explore the mechanisms of conduction of LSMO and LDSMO. The insertion of a small amount of Dy3+ in the La-site of LSMO perovskite oxide increases the value of the activation energy from 0.2106 to 0.5357 eV and enhances electrical resistivity values for almost two orders of magnitude.

Analysis based on scaling relations of critical behaviour at PM-FM phase transition and universal curve of magnetocaloric effect in selected Ag-doped manganites.

The critical behaviour of Pr0.5Sr0.5-x Ag x MnO3 (0 ≤ x ≤ 0.2) samples around the paramagnetic-ferromagnetic phase transition is studied based on isothermal magnetization measurements. The assessments based on Banerjee's criteria reveal the samples undergoing a second-order magnetic phase transition. Various techniques such as modified Arrott plot, Kouvel-Fisher method, and critical isotherm analysis were used to determine the values of the ferromagnetic transition temperature T C, as well as the critical exponents of ß, γ and δ. The values of critical exponents, derived from the magnetization data using the Kouvel-Fisher method, are found to be (ß = 0.43 ± 0.002, 0.363 ± 0.068 and 0.328 ± 0.012), (γ = 1.296 ± 0.007, 1.33 ± 0.0054 and 1.236 ± 0.012) for x = 0.0, 0.1 and 0.2, respectively. This implies that the Pr0.5Sr0.5-x Ag x MnO3 with 0 ≤ x ≤ 0.2 systems does not belong to a single universality class and indicates that the presence of magnetic disorder in the system must be taken into account to fully describe the microscopic interaction of these manganites. With these values, magnetic-field dependences of magnetization at temperatures around T C can be well described following a single equation of state for our samples. From magnetic entropy change (ΔS M), it was possible to evaluate the critical exponents of the magnetic phase transitions. Their values are in good agreement with those obtained from the critical exponents using a modified Arrott plot (MAP). We used the scaling hypotheses to scale the magnetic entropy change and heat capacity changes to a universal curve respectively for Pr0.5Sr0.5-x Ag x MnO3 samples.

Structural and magnetic properties of mixed Co-Ln (Ln = Nd, Sm, Eu, Gd and Ho) diethyleneglycolate complexes.

New hybrid compounds LnCoCl(deg)2 (deg = diethyleneglycolate; Ln = Nd, Sm, Eu, Gd and Ho) have been synthesized by mixing cobalt and rare earth cations in a boiling diethyleneglycol (degH2) medium. Their crystallographic structures have been ab initio solved from synchrotron powder diffraction data. They consist of edge sharing tetrameric sub-units [(Ln2Co2)(deg)4(Cl)2] forming 1D infinite chains along the c parameter of a monoclinic unit cell (SG = C2/c). The five- and seven-coordination of Co(2+) and Ln(3+) cations inferred from the crystallographic results is confirmed by UV-visible absorption and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. In the LnCoCl(deg)2 (Ln = Nd, Sm, Eu, Gd, Ho) series, weak antiferromagnetic superexchange interactions have been evidenced, between high spin Co(2+) and Ln(3+) orbitally degenerate cations. These materials are considered as potential precursors for the simultaneous reduction of Co-Ln-glycolate species into bimetallic nanoparticles by the polyol process.

Acute headache at emergency department: reversible cerebral vasoconstriction syndrome complicated by subarachnoid haemorrhage and cerebral infarction.

Introduction. Reversible cerebral vasoconstriction syndrome is becoming widely accepted as a rare cause of both ischemic and haemorrhagic stroke and should be evocated in case of thunderclap headaches associated with stroke. We present the case of a patient with ischemic stroke associated with cortical subarachnoid haemorrhage (cSAH) and reversible diffuse arteries narrowing, leading to the diagnosis of reversible vasoconstriction syndrome. Case Report. A 48-year-old woman came to the emergency department because of an unusual thunderclap headache. The computed tomography of the brain completed by CT-angiography was unremarkable. Eleven days later, she was readmitted because of a left hemianopsia. One day after her admission, she developed a sudden left hemiparesis. The brain MRI showed ischemic lesions in the right frontal and occipital lobe and diffuse cSAH. The angiography showed vasoconstriction of the right anterior cerebral artery and stenosis of both middle cerebral arteries. Nimodipine treatment was initiated and vasoconstriction completely regressed on day 16 after the first headache. Conclusion. Our case shows a severe reversible cerebral vasoconstriction syndrome where both haemorrhagic and ischemic complications were present at the same time. The history we reported shows that reversible cerebral vasoconstriction syndrome is still underrecognized, in particular in general emergency departments.

[Extraneural soft tissue perineurioma of the nose]. / Périneuriome extraneural des tissus mous localisé au nez.

BACKGROUND: Perineuriomas are tumours derived from the perineurial cells of the neural sheath. Soft tissue perineuriomas are rare. Herein, we report a case of perineurioma localized to the nose. CASE REPORT: A 24-year-old adult presented with a cutaneous nodule 1cm in diameter localized on the nose. Histologically, the tumour corresponded to a well-circumscribed fusocellular dermal proliferation organized in a storiform pattern. After surgical removal, the lesion did not recur. COMMENTS: Extraneural soft tissue perineurioma is usually a benign nerve sheath tumour composed mainly of perineurial cells. Our case occurred in a 24-year-old Caucasian adult. The tumour generally presents as a unique cutaneous nodule corresponding histologically to a well-delineated dermal fusocellular proliferation organized in a storiform pattern that stains positive for EMA and negative for S100. The tumour is usually localized to the trunk and extremities. Location on the nose as in our patient has been rarely reported. Surgical removal of the tumour is the treatment of choice.

Chemotherapy has also an effect on primary tumor in colon carcinoma.

BACKGROUND: This study characterizes the histological effect of chemotherapy (CT) on primary colonic tumors. METHODS: Between 2000 and 2006, 38 patients with stage IV colon cancer underwent resection of the primary, after chemotherapy (CT group, n = 16) or without preoperative CT (control group, n = 22). For all primary tumors, histological analysis included: fibrosis, acellular necrosis, acellular mucin pools, lymphoplasmacytic infiltration, and changes at tumor surface. Tumor regression grade (TRG) was determined by the amount of residual tumor cells and was graded from 1 to 5. RESULTS: No patient had complete histological response. Major histological tumor regression (TRG2) was observed in 70% of patients treated by CT and none of the not treated patients (P < 0.0001). Fibrosis, acellular necrosis, and surface changes were significantly increased in the CT group. TRG in the primary was comparable to the TRG in the corresponding liver metastases for 7/9 patients who underwent both colonic and hepatic resection after CT. CONCLUSION: CT induces major histological response in 70% of colon cancers. Response to CT in the primary and the corresponding liver metastases are correlated. These results support a policy of initial CT management for stage IV colon cancer and may warrant future studies of neoadjuvant CT in locally advanced colon carcinomas.

[Rhinocerebral mucormycosis in four diabetics]. / la mucormycose rhinocérébrale chez le diabétique. A propos de quatre observations.

UNLABELLED: Mucormycosis is caused by a zygomycetes fungus in a vascular location. This fungus is a saprophytic organism which can become pathogenic in specific conditions, particularly in patients with diabetes mellitus. A rhinocerebral localization is common, leading to often fatal devastating sinusitis. Positive diagnosis requires histological proof with characteristic hyphal tissue invasion. Frozen section is essential for diagnosis and management of rhinocerebral mucormycosis. MATERIAL AND METHODS: We report four cases of rhinocerebral mucormycosis in diabetic patients, two men and two women, mean age 51 years. RESULTS: Histological examination showed characteristic hyphae in a vascular localization. Treatment was systemic antifungal therapy with amphotericin B and debridement of necrotic tissue. Three patients recovered completely. One died. CONCLUSION: Rhinocerebral mucormycosis is a rare fungal infection with very poor prognosis. The aim of this study was to report the clinical and pathological features of rhinocerebral mucormycosis and to evaluate the contribution of frozen section for diagnosis and management.