The fabrication of ordered arrays of exchange biased Ni/FeF2 nanostructures

The fabrication of ordered arrays of exchange biased Ni/FeF(2) nanostructures by focused ion beam lithography is reported. High quality nano-elements, with controlled removal depth and no significant re-deposition, were carved using small ion beam currents (30 pA), moderate dwell times (1 micros) and repeated passages over the same area. Two types of nanostructures were fabricated: square arrays of circular dots with diameters from 125 +/- 8 to 500 +/- 12 nm and periodicities ranging from 200 +/- 8 to 1000 +/- 12 nm, and square arrays of square antidots (207 +/- 8 nm in edge length) with periodicities ranging from 300 +/- 8 to 1200 +/- 12 nm. The arrays were characterized using scanning ion and electron microscopy, and atomic force microscopy. The effect of the patterning on the exchange bias field (i.e., the shift in the hysteresis loop of ferromagnetic Ni due to proximity to antiferromagnetic FeF(2)) was studied using magneto-transport measurements. These high quality nanostructures offer a unique method to address some of the open questions regarding the microscopic origin of exchange bias. This is not only of major relevance in the fabrication and miniaturization of magnetic devices but it is also one of the important proximity phenomena in nanoscience and materials science.

Paclitaxel plus carboplatin (PC) in patients with metastatic melanoma (MM): Experience in a single institution

e20019

Background: The number of agents active in patients with metastatic melanoma is limited and cure is not an objective for treatment at this stage, so that clinical benefit in these patients is the most important. The aim of the study was to evaluate the efficacy and safety of combination regimen consisting of paclitaxel and carboplatin as second-line chemotherapy, in patients with MM. Based on reports of responses to PC, 17 patients with MM was treated at the National Cancer Institute of Mexico. Methods: We evaluated retrospectively the combination of PC in patients with MM. Data regarding patient characteristics and outcomes were abstracted from medical records of NCI of Mexico from 01/05 to 12/08. The regimen was weekly paclitaxel (at a dose of 80 mg/m2) received on days 1, 8, and 15 of a 21-day cycle and carboplatin (AUC 5) on day 1. Response evaluation was using RECIST and toxicity was according to National Cancer Institute Common Toxicity Criteria. This study was approved by the hospital ethics committee. Results: Seventeen patients with MM were treated with PC. All patients were previously treated (and failed) with dacarbazine (DTIC). Sixteen were assessable for response with three cycles of chemotherapy and seventeen for toxicity. One patient was deemed to be ineligible because they presented severe hypersensitivity reaction to paclitaxel at beginning. Objective partial response were obtained in 4 patients (25%); 8 stable disease (50%) at least four months. No patient had a complete response to therapy. Progression disease was in 4 patients (25%). In 12 (75%) we noted clinical benefit. The median time to disease progression for the entire group was 4.2 months (range, 1–11 mos), with a median overall survival of 8.1 months (range, 5.6–10.5 mos). The toxicity grade 3 reported was thrombocytopenic in 2 patients (11%) and anemia in one patient (6%). Additional patients had reversible toxicities grade 3 including alopecia, nausea and fatigue; 2 of them presented moderate hypersensitivity reactions to paclitaxel. No toxic death was noted. Conclusions: The PC combination appears to be safety and well tolerated in second line chemotherapy in MM, however we need more patients to demonstrate a true clinical benefit, we outcomes are according with other clinical reports.

No significant financial relationships to disclose.

Role of the antiferromagnetic bulk spin structure on exchange bias

The cooling field dependence of the exchange bias field in ferromagnet/antiferromagnet (FM/AF) multilayers demonstrates that the bulk AF spin structure plays a crucial role on the origin of exchange bias. FM/AF/FM trilayers were designed to eliminate any interlayer exchange coupling between the FM slabs. By choosing the magnetic cooling field, the AF is ordered below its Néel temperature with the FM layers fully saturated either parallel or antiparallel to each other. The significant difference in the exchange bias field between these two cooling configurations confirms that exchange bias cannot be a purely interfacial effect and that the bulk AF moments play a significant role in pinning the uncompensated spins at the AF/FM interface. This experiment also demonstrates that the mechanism responsible for coercivity enhancement has a different origin and is independent of the process that gives rise to exchange bias.

Effect of a 10-day ageing at 30°C on the texture of dry-cured hams processed at temperatures up to 18°C in relation to raw meat pH and salting time

The aim of this study was to investigate the effect of a 10-day ageing at 30±2°C on the texture of dry-cured hams processed at temperatures up to 18±2°C for 12 months in relation with raw ham pH and salting time. Three pH groups (semimembranosus muscle at 24h post-mortem: Low pH<5.7, Medium pH=5.7⩽pH⩽5.9, and High pH>5.9), three salting times (6d, 10d and 14d) and two ageing temperatures (18°C and 30°C) were investigated. Physicochemical characteristics, instrumental and sensory texture and product sliceability were evaluated on biceps femoris and semimembranosus muscles. Hams with pH(SM24)<5.7 should be avoided in order to reduce the incidence of texture problems in dry-cured ham elaboration. Texture problems are especially important in hams with a reduced salt content that are mechanically sliced (not frozen). A 10-day ageing at 30°C could be useful for reducing the soft texture problems in dry-cured hams processed at temperatures up to 18°C for 12 months without affecting the product flavour.

Carcass and meat quality traits of wild boar (Sus scrofas. L.) with 2n=36 karyotype compared to those of phenotypically similar crossbreeds (2n=37 and 2n=38) raised under same farming conditions. 1. Carcass quantity and meat dressing

The aim of this study was to compare wild boar (chromosomal number 2n=36) to phenotypically similar animals of 2n=37 and 2n=38 chromosomes (crossbreeds) with respect to live weight, carcass yield, meat yield, fat and weight of inner organs. All animals were born and raised on the same farm and slaughtered at 39 weeks. The final live weight of wild boar 2n=36 was significantly lower (47.2kg) as compared to crossbreeds (80.0kg). Animals 2n=36 had more carcass yields (65.5%) than 2n=37 karyotype (64.9%) and 2n=38 (64.4%). Wild boar had the highest yields for the cuts with bones and boneless cuts compared to crossbreeds. Therefore, variations in karyotype are accompanied by differences in some carcass quantitative traits, i.e., 2n=36 grow and fatten slower than crossbreeds 2n=37 and 2n=38.

GSTP1 and MTHFR polymorphisms are related with toxicity in breast cancer adjuvant anthracycline-based treatment

We have analyzed several members of drug-metabolizing enzymes (DMEs) and other polymorphisms in genes implicated in tumor aggressivity regarding possible links between specific genetic variability in systemic drug bioavailability and toxicity in breast cancer patients treated with adjuvant anthracycline-based treatment. PCR-RFLP and sequencing analyses technique were used for evaluating fourteen previously identified polymorphisms in 94 patients. GSTP1A>G and MTHFR 1298A>C genotypes remained as significant predictors in a multivariate logistic regression analysis. GSTP1 polymorphism was linked to haematological GIII-IV toxicity (P = 0.044, HR= 6.4, 95% CI = 1.05 to 39. Increased and significant HR was obtained for MTHFR-1298 AC+CC group when non-haematological toxicities GIII-IV toxicities were evaluated (HR = 24; 95% CI = 2.3 to 254), P = 0.008. Our results suggest that GSTP1 and MTHFR genotypes may be consider relevant and independent factors of toxicity in adjuvant anthracycline-based treatment of breast cancer.

Découverte et structure cristallographique d’une apolipoprotéine humaine

We report the serendipitous discovery of a human plasma phosphate binding protein (HPBP). This 38 kDa protein is co-purified with paraoxonase (PON1). The association between HPON1 and HPBP is modulated by phosphate and calcium concentrations. The HPBP X-ray structure solved at 1.9 A resolution is similar to the prokaryotic phosphate solute-binding proteins (SBPs) associated with ATP binding cassette transmembrane transporters, though phosphate-SBPs have never been characterized or predicted from nucleic acid databases in eukaryotes. However, HPBP belongs to the family of ubiquitous eukaryotic proteins named DING, meaning that phosphate-SBPs are also widespread in eukaryotes. The absence of complete genes for eukaryotic phosphate-SBP from databases is intriguing, but the astonishing 90% sequence conservation of genes between evolutionary distant species suggests that the corresponding proteins play an important function. HPBP is the first identified transporter capable of binding phosphate ions in human plasma. Thus it is thought to become a new predictor and a potential therapeutic agent for phosphate-related diseases such as atherosclerosis.