Tuning structural and magnetic properties of Fe oxide nanoparticles by specific hydrogenation treatments.

Structural and magnetic properties of Fe oxide nanoparticles prepared by laser pyrolysis and annealed in high pressure hydrogen atmosphere were investigated. The annealing treatments were performed at 200 °C (sample A200C) and 300 °C (sample A300C). The as prepared sample, A, consists of nanoparticles with ~ 4 nm mean particle size and contains C (~ 11 at.%), Fe and O. The Fe/O ratio is between γ-Fe2O3 and Fe3O4 stoichiometric ratios. A change in the oxidation state, crystallinity and particle size is evidenced for the nanoparticles in sample A200C. The Fe oxide nanoparticles are completely reduced in sample A300C to α-Fe single phase. The blocking temperature increases from 106 K in A to 110 K in A200C and above room temperature in A300C, where strong inter-particle interactions are evidenced. Magnetic parameters, of interest for applications, have been considerably varied by the specific hydrogenation treatments, in direct connection to the induced specific changes of particle size, crystallinity and phase composition. For the A and A200C samples, a field cooling dependent unidirectional anisotropy was observed especially at low temperatures, supporting the presence of nanoparticles with core-shell-like structures. Surprisingly high MS values, almost 50% higher than for bulk metallic Fe, were evidenced in sample A300C.

On the synthesis and physical properties of iron doped SnO2 nanoparticles.

The synthesis of iron doped tin oxide by pulsed laser pyrolysis is reported. The as obtained nanoparticles have a dominant SnO2 phase (as revealed by Wide Angle X-ray Scattering), with particles of the order of 10 nm. The doping with iron or iron oxide triggers magnetic properties as confirmed by SQUID experiments. EDX measurements supported the presence of Fe while Wide Angle X-ray Scattering failed to sense any iron or iron-oxide phase. It is concluded that Fe is well dispersed within the tin-oxide nanoparticles. The coercitive field has a complex dependence on the Fe/Sn content suggesting that the magnetization is not controlled solely by the amount of Fe dispersed within the nanoparticles.

Iron oxide-based nanoparticles with different mean sizes obtained by the laser pyrolysis: structural and magnetic properties.

Nano-sized iron oxide-based particles have been directly synthesized by the laser induced pyrolysis of a mixture containing iron pentacarbonyl/air (as oxidizer)/ethylene (as sensitizer). In this paper we further demonstrate the possibility to vary the chemical composition and the nanoparticle dimensions of the iron oxide-based materials by handling the oxidation procedure in the frame of the laser pyrolysis process. Thus, nanoparticles with major maghemite/magnetite content may change composition into mixtures with variable amounts of three components: major gamma-Fe2O3/Fe3O4 iron oxide, metallic Fe and cementite Fe3C. By X-ray diffraction (XRD) it is found that the relative proportion of these phases differs in function of the reaction temperature (laser power). As revealed by transmission electron microscopy (TEM), mean particle sizes between about 4 nm and 6 nm and between about 9 and 11 nm may be prepared by varying the oxidation procedure and the laser power, respectively. By the controlled heating of samples (maximum temperature 185 degrees C), increased crystallinity for the gamma-Fe2O3/Fe3O4 oxide phase was found as well as an increase of the mean particle diameters. The examination of the magnetization curves for samples obtained for different laser powers indicates notable differences in the magnetic behavior and parameters. The temperature dependent Mossbauer measurements confirm the formation of larger particles at higher laser power densities as well as the presence of inter-particle magnetic interactions. On this basis, the estimation of phase composition for the different representative samples is given.

[Expression of CA-125 in ovarian cancer]. / Expresia CA-125 n unele tumori ovariene.

UNLABELLED: Ovarian carcinoma is a heterogeneus disease. Pathologists classify it in serous, clear cell, endometrioid and mucinos subtypes. Each of these subtypes is associated with different genetic risk factors and molecular events during oncogenesis and it is characterised by distinct mRNA expression profiles. MATERIAL AND METHOD: We have studied 55 pacients with ovarian tumours who underwent surgery in Clinic "Elena Doamna", Iasi between 2005-2008. CA-125 value was determined pre or postoperator. RESULTS: We have investigated the relationship between tumoral type and CA125 value in all studied cases. CONCLUSIONS: By demonstrating the correlations between biomarker expression with stage or prognosis and by demonstrating the variation in expression rates between subtypes we offer persuasive evidence supporting the view that ovarian carcinoma subtypes are different diseases and the value of the biomarker is not always correlated with malignancy.

[Connective tissue modifications in the pelvi-perineal prolapse at menopause]. / Modificari ale tesutului conjunctiv la menopauza in prolapsul pelvi-perineal.

AIM: The qualitative and quantitative analysis of the histological structure of the Levator Ani (LA) muscle at female patients with pelvi-perineal prolapse (PPP). MATERIAL AND METHODS: After having taken biopsies of LA from 50 patients with PPP, a microscopic qualitative and quantitative study has been performed. This study was done by comparison with a control lot. RESULTS: The connective, muscular and vascular modifications in the structure of the LA are presented, in connection with the hormonal status of patients with PPP and also the influence of these modifications on the anatomic and functional integrity of the pelvic floor. CONCLUSIONS: Applying the hormonal maintenance treatment for menopause patients has become strictly necessary, both in the PPP prophylaxis and after restoring surgeries.

[Genital hematoma--local obstetrical trauma or pregnancy disorder?]. / Hematomul genital--traumatism obstetrical local sau disgravidie?

The general haematoma is a disease which appears during labour and affects the vulvar, vaginal or the parametrial tissues. The study of this affection implies the discussions of some special aspects, as the distinction between this disease and the traumatic complications of the labour; the observation that the genital haematoma is frequently associated with proteinuria and primiparity which leads to the possible inclusion of this disease among pregnancy toxaemias; the clinical importance of this affection, the severe forms prejudicing the mother's life. In the genital haematoma pathogenesis it is important to notice that this disease is the consequence of a vascular rupture, most frequently affecting the small vessels or the capillaries, and it is favoured by the increased vascular flow during gravidity and by the tissues' slip on the gravidic inhibition background. After mentioning the predisposing factors, details about the pathological anatomy are given and a new classification is proposed, mostly based on clinical and less on anatomical features. The clinical symptoms and the treatment are presented on a large scale, discussing the latest informations in the specialty literature.

[Family planning with different contraceptive methods]. / Planificarea familiala prin diferite metode contraceptive.

PIP: Female hormonal contraceptives, introduced commercially in 1959, contained 10 mg of norethynodrel and .15 mg of mestranol. The estrogen and progesterone doses were progressively reduced over time. In 1989, approximately 60 million couples used oral contraceptives (OCs) ranging from 1% in Japan to 40% in the Netherlands. The monophasic pill contains .01 - .04 mg of ethinyl estradiol (EE), and the biphasic pill contains increasing doses of progesterone and estroprogesterone in the course of the menstrual cycle. Triphasic combined pills contain an initially dominant estrogen dose. In oral sequential pills, estrogen is given on days 14-16 followed by a estroprogesterone for 5-7 days. Micropills with progesterone, injectables with medroxyprogesterone, and 3rd-generation OCs such as gestoden with a low progesterone dose of .04 mg/day and reduced androgenic activity are among other OCs. The OCs are administered in 21-22 day packets. Absolute contraindications include history of venous thrombosis, atherogenic lipid profile, hormone-dependent cancer, and allergy. Relative contraindications include arterial ailments, smoking, hypertension, older age, obesity, and familial history of cardiovascular and cerebrovascular accidents. Interactions with antibiotics (ampicillin and tetracycline) occur as the modified intestinal flora reduces the level of deconjugated EE. Most frequent side effects are depression, modification of libido, ocular disorders, headache, and urinary infection. Benefits include favorable modification of menstrual cycle, and reduction of endometriosis and endometrial and ovarian cancer. Systemic risks such as cardiovascular and blood coagulation effects occur mainly with high-dose OCs. Further topics addressed are the cancer risk and protective effect of OCs, postcoital OCs, traditional contraception, the IUD, RU-486, implants, vaccination with the human antigonadotropine, and the vaginal ring.^ieng

[THe role of biopsy in the early diagnosis of cancer of the cervix uteri]. / Rolul biopsiei în diagnosticul precoce al cancerului de col uterin.

Among the actions of early diagnosis of uterine cervix cancers, the sequence cytologic smear, colposcopy, cervix biopsy is well-known. The authors draw the attention that in some situations the cytologic smear and colposcopy are not sufficient and it is only biopsy that defines the nature of the lesion and may give therapeutic indications. Out of a series of 55 women to whom a cervix biopsy was performed, there were 27 cases in which biopsy was justified, showing either a severe lesion or the presence of koilocytes. The authors plead for a more frequent use of cervix biopsy as a means of early diagnosis of uterine cervix cancer or of its dysplasias.