Tuning the aspect ratio of silver nanospheroids embedded in silica: erratum.

We present a corrigendum to our Letter [Opt. Lett.35, 703 (2010)10.1364/OL.35.000703]. In the original Letter we inadvertently included in Fig. 2(a) a TEM micrograph corresponding to a different, but very similar, sample. This corrigendum replaces Fig. 2(a) with a correct version. Since the main results are rather based in optical absorption measurements, and their modeling by using the T-matrix method, this correction does not affect the results and conclusions of the original Letter.

Enhanced ultrafast optomagnetic effects in room-temperature ferromagnetic Pt nanoclusters embedded in silica by ion implantation.

Ferromagnetic-like behavior at room temperature (300 K) was observed in Pt particles embedded in ion-implanted silica matrices. Results in samples integrated by ultra-small photoluminescent Pt clusters (<2 nm) were compared with samples containing exclusively larger plasmonic Pt nanoparticles (>3 nm). The ferromagnetic behavior coexists simultaneously with a diamagnetic response. Enhanced diamagnetic response of one order of magnitude was observed compared to typical diamagnetism in pure silica, and it is increased with the mean diameter of the Pt particles. Besides, a larger sensitivity to an external field was observed in the ferromagnetic response of the nanostructures with a characteristic saturation at 20 kOe. This ferromagnetic behavior was only observed in the samples with nucleated Pt particles. The magnitude of the saturation magnetization shows up to a fivefold increase in the samples with smaller particle size and larger particle density. Saturation magnetization was observed between 3-15 × 10-4 emu g-1, with remanent magnetization of 0.2-0.6 × 10-4emu g-1, measured at 300 K. Coercitive fields also decrease in samples with smaller size and particles density, with values of 114 and 300 Oe. At lower temperatures (5 K) the saturation magnetization increases, as it would be expected from a ferromagnetic state. Optomagnetic response was studied by inverse Faraday effects and induced photomagnetization with circular polarized picosecond pulsed light at 1064 nm wavelength. Results showed that samples with a stronger ferromagnetic response exhibit larger Faraday rotation up to 5.3 × 103deg cm-1 by light excitations with irradiances between 50 and 180 GW cm-2. These findings have immediate applications in multifunctional solid-state magneto-optical devices such as optical isolators, high-data storage devices and ultrafast all-optical switching of magnetization.

Reliability of the MDi Psoriasis® Application to Aid Therapeutic Decision-Making in Psoriasis. / Fiabilidad de una aplicación de ayuda a la toma de decisiones terapéuticas en el paciente con psoriasis (MDi Psoriasis®).

BACKGROUND: Therapeutic decisions in psoriasis are influenced by disease factors (e.g., severity or location), comorbidity, and demographic and clinical features. OBJECTIVE: We aimed to assess the reliability of a mobile telephone application (MDi-Psoriasis) designed to help the dermatologist make decisions on how to treat patients with moderate to severe psoriasis. METHOD: We analyzed interobserver agreement between the advice given by an expert panel and the recommendations of the MDi-Psoriasis application in 10 complex cases of moderate to severe psoriasis. The experts were asked their opinion on which treatments were most appropriate, possible, or inappropriate. Data from the same 10 cases were entered into the MDi-Psoriasis application. Agreement was analyzed in 3 ways: paired interobserver concordance (Cohen's κ), multiple interobserver concordance (Fleiss's κ), and percent agreement between recommendations. RESULTS: The mean percent agreement between the total of 1210 observations was 51.3% (95% CI, 48.5-54.1%). Cohen's κ statistic was 0.29 and Fleiss's κ was 0.28. Mean agreement between pairs of human observers only, excluding the MDi-Psoriasis recommendations, was 50.5% (95% CI, 47.6-53.5%). Paired agreement between the recommendations of the MDi-Psoriasis tool and the majority opinion of the expert panel (Cohen's κ) was 0.44 (68.2% agreement). CONCLUSIONS: The MDi-Psoriasis tool can generate recommendations that are comparable to those of experts in psoriasis.

Nanoparticle containing channel waveguides produced by a multi-energy masked ion-implantation process.

We present the fabrication and characterization of channel waveguides based on composites containing silver nanoparticles. The substrate employed is silica and the nanoparticles were produced by a masked ion-implantation technique. Multiple implantation processes were made at different energies in order to produce waveguides with an appropriate width. We also present results for the characterization of the waveguiding properties of the devices produced.

Poly(methyl methacrylate) coating of soft magnetic amorphous and crystalline Fe,Co-B nanoparticles by chemical reduction.

The structural and magnetic properties of a collection of nanoparticles coated by Poly(methyl methacrylate) through a wet chemical synthesis have been investigated. The particles display either an amorphous (M = Fe, Co) M-B arrangement or a mixed structure bcc-Fe and fcc-Co + amorphous M-B. Both show the presence of a metal oxi-hydroxide formed in aqueous reduction. The organic coating facilitates technological handling. The cost-effective synthesis involves a reduction in a Poly(methyl methacrylate) aqueous solution of iron(II) or cobalt(II) sulphates (< 0.5 M) by sodium borohydride (< 0.5 M). The particles present an oxidized component, as deduced from X-ray diffraction, Mössbauer and Fe- and Co K-edge X-ray absorption spectroscopy and electron microscopy. For the ferrous alloys, this Fe-oxide is alpha-goethite, favoured by the aqueous solution. The Poly(methyl methacrylate) coating is confirmed by Fourier transform infrared spectroscopy. In pure amorphous core alloys there is a drastic change of the coercivity from bulk to around 30 Oe in the nanoparticles. The mixed structured alloys also lie in the soft magnetic regime. Magnetisation values at room temperature range around 100 emu/g. The coercivity stems from multidomain particles and their agglomeration, triggering the dipolar interactions.

Ultrafast optical phase modulation with metallic nanoparticles in ion-implanted bilayer silica.

The nonlinear optical response of metallic-nanoparticle-containing composites was studied with picosecond and femtosecond pulses. Two different types of nanocomposites were prepared by an ion-implantation process, one containing Au nanoparticles (NPs) and the other Ag NPs. In order to measure the optical nonlinearities, we used a picosecond self-diffraction experiment and the femtosecond time-resolved optical Kerr gate technique. In both cases, electronic polarization and saturated absorption were identified as the physical mechanisms responsible for the picosecond third-order nonlinear response for a near-resonant 532 nm excitation. In contrast, a purely electronic nonlinearity was detected at 830 nm with non-resonant 80 fs pulses. Regarding the nonlinear optical refractive behavior, the Au nanocomposite presented a self-defocusing effect, while the Ag one presented the opposite, that is, a self-focusing response. But, when evaluating the simultaneous contributions when the samples are tested as a multilayer sample (silica-Au NPs-silica-Ag NPs-silica), we were able to obtain optical phase modulation of ultra-short laser pulses, as a result of a significant optical Kerr effect present in these nanocomposites. This allowed us to implement an ultrafast all-optical phase modulator device by using a combination of two different metallic ion-implanted silica samples. This control of the optical phase is a consequence of the separate excitation of the nonlinear refracting phenomena exhibited by the separate Au and Ag nanocomposites.

Cleavage and activation of LIM kinase 1 as a novel mechanism for calpain 2-mediated regulation of nuclear dynamics.

Calpain-2 (CAPN2) is a processing enzyme ubiquitously expressed in mammalian tissues whose pleiotropic functions depend on the role played by its cleaved-products. Nuclear interaction networks, crucial for a number of molecular processes, could be modified by CAPN2 activity. However, CAPN2 functions in cell nucleus are poorly understood. To unveil CAPN2 functions in this compartment, the result of CAPN2-mediated interactions in cell nuclei was studied in breast cancer cell (BCC) lines. CAPN2 abundance was found to be determinant for its nucleolar localization during interphase. Those CAPN2-dependent components of nucleolar proteome, including the actin-severing protein cofilin-1 (CFL1), were identified by proteomic approaches. CAPN2 binding, cleavage and activation of LIM Kinase-1 (LIMK1), followed by CFL1 phosphorylation was studied. Upon CAPN2-depletion, full-length LIMK1 levels increased and CFL1/LIMK1 binding was inhibited. In addition, LIMK1 accumulated at the cell periphery and perinucleolar region and, the mitosis-specific increase of CFL1 phosphorylation and localization was altered, leading to aberrant mitosis and cell multinucleation. These findings uncover a mechanism for the role of CAPN2 during mitosis, unveil the critical role of CAPN2 in the interactions among nuclear components and, identifying LIMK1 as a new CAPN2-target, provide a novel mechanism for LIMK1 activation. CFL1 is crucial for cytoskeleton remodeling and mitosis, but also for the maintenance of nuclear structure, the movement of chromosomes and the modulation of transcription frequently altered in cancer cells. Consequently, the role of CAPN2 in the nuclear compartment might be extended to other actin-associated biological and pathological processes.

Tuning the aspect ratio of silver nanospheroids embedded in silica.

A method is proposed to control the aspect ratio (epsilon) of elongated nanoparticles obtained by ion implantation in a transparent matrix. The procedure was tested for Ag spheroids in silica and we could accurately change epsilon in the range from the maximum value obtained by the ion implantation (around 3.0 in this case) to 1.0 (spherical shape). The values of epsilon were determined in several steps from optical extinction spectroscopy measurements, by fitting the modification and splitting of the surface plasmon resonance peak, using the T-matrix method. In the initial (maximum deformation) and final (undeformed) states, transmission electron microscopy images were obtained, showing a good agreement with the T-matrix results in both cases.

Phonon softening on the specific heat of nanocrystalline metals.

Specific heat enhancement in several common nanocrystalline metals is established by comparison with their bulk counterparts. Measurements were carried out in Fe, Cu, Ni and binary alloy LaAl(2). The excess specific heat is evidenced as a low temperature peak below 65 K and a high temperature slope above 150 K. The experimental data are in good agreement with a model which considers contributions from the grain boundary and core atoms in the nanoparticles. This model is supported by Raman spectroscopy measurements, showing a softening of the frequency phonon modes associated with a size reduction and increase of the atomic disorder.

[Scientific Presentations at the meetings of the Spanish Pediatric Nephrology Association (AENP), 1988-2007]. / Comunicaciones científicas en los congresos de la Asociación Española de Nefrología Pediátrica (AENP), 1988-2007.

UNLABELLED: OBJECTIVES AND STUDY: To find out that characteristics of the scientific presentations given at the AENP's meetings in the past 20 years. METHODS: We reviewed in the scientific programs of the AENP's meetings of the past 20 years: number of presentations, number of participating institutions, institutions that provided the majority of the presentations, presentation format, number of studies involving experimental nephrology, topics most commonly presented. RESULTS: There have been 1,119 presentations in the past 20 years, 45/year between 88-92 and 67/year between 03-07. Ninety-one institutions participated in the meetings, 17/year between 88-92 and 34/year between 03-07. Pediatric Nephrology unit from the H. La Paz (Madrid) contributed the most presentations. Poster presentations were accepted at the ANEP meetings after 1995. Since then, 369 of the 815 presentations followed this format. Between 88-07 only 16 presentations dealt with experimental nephrology. The most common topics of presentation were glomerular disease (203) and urinary tract infection/VUR (132). Fifty-one presentations dealt with dialysis (almost 2/3 peritoneal). Transplantation was the topic of 123 presentations. Of the 21 presentations on molecular genetics only one happened before 1998. CONCLUSIONS: The poster is a useful alternative in scientific presentations which has allowed an increase in presentations, authors and institutions participating in the ANEP meetings. The main topic of presentation was glomerular disease. The frequency of presentations dealing with transplantation has increased in the last years. The past decade has seen more presentations on molecular genetics, but presentations dealing with experimental nephrology are still infrequent.

Surface morphology of amorphous SiO2 substrates bombarded with 1.0 MeV Si+ ions.

Surface pattern formation on amorphous SiO2 substrates by implantation of 1.0 MeV Si+ ions at a current of 1.3 µA at 70° angle is reported. Surface micrometer sized ripples perpendicular to the ion beam direction are formed, observed by scanning electron microscopy and atomic force microscopy. The morphological features are more or less similar for different fluences. The formation of surface ripples at this energy is discussed in terms of ion stopping mechanisms and patterns obtained within the low- and medium-energy ranges.

Breakdown of the coherence effects and Fermi liquid behavior in YbAl3 nanoparticles.

A change in the Kondo lattice behavior of bulk YbAl3 has been observed when the alloy is shaped into nanoparticles (≈12 nm). Measurements of the electrical resistivity show inhibited coherence effects and deviation from the standard Fermi liquid behavior (T 2-dependence). These results are interpreted as being due to the effect of the disruption of the periodicity of the array of Kondo ions provoked by the size reduction process. Additionally, the ensemble of randomly placed nanoparticles also triggers an extra source of electronic scattering at very low temperatures (≈15 K) due to quantum interference effects.

Absorptive and refractive nonlinearities by four-wave mixing for Au nanoparticles in ion-implanted silica.

We report a theoretical and experimental study on the real and imaginary part of the third-order nonlinear optical susceptibility at 532 nm and 7 ns pulse for high-purity silica samples containing Au nanoparticles prepared by ion implantation. We present a method for measuring the magnitude and sign of refractive and absorptive nonlinearities based on four-wave mixing (FWM). This method is derived from a comparison of the light intensities of incident and self-diffracted polarized waves. In the nanosecond regime the samples exhibit saturable absorption and it seems that a thermal effect is the mechanism responsible of nonlinearity of index.

[Treatment of obesity in a hospital endocrinology clinic. Influence of parental body mass index]. / Tratamiento de la obesidad en la consulta de endocrinología de un hospital. Influencia del índice de masa corporal de los padres.

INTRODUCTION: Parental obesity is a risk factor for childhood obesity. The aim of this study was to determine if parental obesity influences the adherence and success of obesity treatment in a hospital paediatric endocrinology clinic. MATERIAL AND METHODS: An analytical, prospective, longitudinal study was conducted on obese children aged 4-14. An initial body mass index (BMI), and again at 6 months after receiving health, hygiene and dietary recommendations. Success was considered as a decrease of 0.5 in the BMI Z-score, and adherence to attending the 6-month review. Parental BMI was determined to identify overweight. The χ(2) test was used for qualitative variables and the T-Student test for quantitative (significance, p<<.05). RESULTS: The study included 100 children (52 male), 9.9±2.7 years old, BMI 28.1± 4.5kg/m(2) and BMI Z-Score 3.11±0.98. (85% had a BMI Z-score>3). More than half (59%) of the children had one or both parents obese (41 fathers and 37 mothers were obese). Treatment was not adhered to by 25 children. Adherence was worse if both parents were obese OR 3.65 (1.3 to 10.5) (P<=.01) and adherence was better if the mother was not obese, although the father was (P=.01). The treatment had significant success in 40 patients. If the mother was the only obese one in the family, the possibility of treatment failure was greater OR 5.6 (1.4 to 22.4) (P<.01) CONCLUSIONS: A high percentage of children with severe obesity have obese parents. The mother has an important influence on adherence and response to treatment for the severely obese child.

[Evaluation of isometric force in lower limbs and body composition in preterm infants]. / Valoración de fuerza isométrica en extremidades inferiores y composición corporal en prematuros.

INTRODUCTION: Strength is a physical quality with a clear influence on quality of life. It is determined by the structure of the musculoskeletal system, and depends on the muscular structure. It has been described that prematurity conditions both qualities. The aims of this study are to determine whether prematurity is associated with strength or body composition and evaluate the relationship between prematurity, strength and muscle mass. MATERIAL AND METHODS: Case-control study. Participants were premature 7-to-11 year-old children and full-term birth controls. Strength was measured by a strength gauge and body composition from DEXA (duel-energy X-ray absorptiometry) scans. A total of 89 subjects were included and divided into three groups: 30 prematures with birth-weight ≤ 1500g, 29 prematures with birth-weight 1500-2000g, and 30 controls. RESULTS: Weight and BMI z-score was lower in the premature group. No differences were found in muscular mass or strength between groups. A ratio was established between strength and weight or muscular mass. It was observed that it was possible for them to move four times their weight, without finding any differences between groups or a relationship with birth-weight. CONCLUSIONS: Between 7 and 11 years of age, children who were premature have lower weight and BMI than the rest of the children. However, there were no differences in body composition or strength between preterm children and controls.

[Amount of sleep and changes in its patterns in children less than two years old]. / Cuantificación del sueño y presencia de alteraciones en la duración del sueño en niños menores de 2 años.

OBJECTIVES: The aim is to study the sleep duration and the 24-hour sleep distribution pattern in children under 2 years-old from two different areas of Spain, as well as to determine the prevalence of abnormal sleep duration and the influence of age on this prevalence, and compare them with the already published data. MATERIAL AND METHODS: An observational, descriptive and cross-sectional study on children from two health centers: one in Castilla y León and the other in Asturias. Their parents completed the Brief Infant Sleep Questionnaire (BISQ). Daytime and nighttime sleep duration was assessed, with percentiles being used to evaluate the results. Two groups were created: one according to the age (children under or above 6 months), and the other according to the area. RESULTS: A total of 125 children were studied (73 males). The nighttime sleep duration increased from 8.28±2.06 hours to 10.43±1.21 hours (P=.0001) and the daytime sleep decreased from 4.61±2.66 to 1.96±0.79 hours (P=.0001) for children under 6 months and above 6 months, respectively. The children from Castilla y León slept more during daytime than those from Asturias (3.91±2.67 vs 3.00±2.09 hours, P=.041). Nineteen children had a total sleep duration below the 2nd percentile. A sleep duration below normal percentiles was observed in children under 6 months (14/72 vs 5/53, P=.006). CONCLUSIONS: As children grow older, they substitute daytime sleep for nighttime sleep. Approximately 15% of the children under 2 years-old may have changes in sleep duration, and is more common in children under 6 months.

Magnetic phase diagram of superantiferromagnetic TbCu2 nanoparticles.

The structural state and static and dynamic magnetic properties of TbCu2 nanoparticles are reported to be produced by mechanical milling under inert atmosphere. The randomly dispersed nanoparticles as detected by TEM retain the bulk symmetry with an orthorhombic Imma lattice and Tb and Cu in the 4e and 8h positions, respectively. Rietveld refinements confirm that the milling produces a controlled reduction of particle sizes reaching ≃6 nm and an increase of the microstrain up to ≃0.6%. The electrical resistivity indicates a metallic behavior and the presence of a magnetic contribution to the electronic scattering which decreases with milling times. The dc-susceptibility shows a reduction of the Néel transition (from 49 K to 43 K) and a progressive increase of a peak (from 9 K to 15 K) in the zero-field-cooled magnetization with size reduction. The exchange anisotropy is very weak (a bias field of ≃30 Oe) and is due to the presence of a disordered (thin) shell coupled to the antiferromagnetic core. The dynamic susceptibility evidences a critical slowing down in the spin-disordered state for the lowest temperature peak associated with a spin glass-like freezing with a tendency of zv and ß exponents to increase when the size becomes 6 nm (zv ≃ 6.6 and ß ≃ 0.85). A Rietveld analysis of the neutron diffraction patterns 1.8 ≤ T ≤ 60 K, including the magnetic structure determination, reveals that there is a reduction of the expected moment (≃80%), which must be connected to the presence of the disordered particle shell. The core magnetic structure retains the bulk antiferromagnetic arrangement. The overall interpretation is based on a superantiferromagnetic behavior which at low temperatures coexists with a canting of surface moments and a mismatch of the antiferromagnetic sublattices of the nanoparticles. We propose a novel magnetic phase diagram where changes are provoked by a combination of the decrease of size and the increase of microstrain.

[Evaluation of the capacity of elderly patients to make decisions about their health]. / Evaluación de la capacidad de toma de decisiones sobre su salud en pacientes ancianos.

OBJECTIVE: To assess the decision-making capacity and variables related to this, in elderly patients in a home care program. MATERIAL AND METHODS: A cross-sectional study was conducted on 130 patients assigned to home care program or in social welfare residences of an urban health centre. Demographic variables, as well as comorbidities, social support, institutionalisation, number of drugs used, degree of dependence (Barthel Index), cognitive function (Pfeiffer) were collected. The primary endpoint was the capacity for decision-making about their health assessed using the Aid to Capacity Evaluation (ACE) tool. RESULTS: There was a prevalence of 58.5% capacity. There was an association between ability and independence for activities of daily living (odds ratio (OR): 12.214; Confidence interval 95% (95% CI): 3.90 to 32.29, P <.0001) and function intellectual intact (OR: 282.750, 95% CI 34.0 to 2351.2, P <.0001). Numeric variables associated with the capacity for decision-making that had a more important effect size were the Barthel index (d: -1.398) and Pfeiffer index (d: 3.084). CONCLUSIONS: The prevalence of incapacity to make decisions about their health in elderly patients who are cared for in their homes is high. The level of dependence in activities of daily living and the deterioration of intellectual function are factors associated with the presence of this capacity.

Magnetic disorder in diluted FexM100-x granular thin films (M=Au, Ag, Cu; x < 10 at.%).

Nanogranular thin films of Fe7Au93, Fe7Ag93 and Fe9Cu91 have been sputtered onto Si(100) substrates with the aim of studying the magnetic interactions. X-ray diffraction shows a major noble metal matrix with broad peaks stemming from (111) textured fcc-Au, Ag and Cu. The noble metal forms a nanogranular environment, as confirmed by transmission electron microscopy, with mean particle sizes below 10 nm. The high magnetoresistance (>6%) reveals the existence of Fe nanoparticles. X-ray absorption near edge spectroscopy confirms the presence of a bcc-Fe atom arrangement and some dissolved Fe atoms in the matrix, and XMCD shows the polarization of Au by the Fe nanoparticles. DC-magnetization displays a field-dependent irreversibility produced by the freezing of magnetic nanoparticles into a superspin-glass state. The hysteresis loops remain unsaturated at 5 K and 45 kOe. The coercivity displays a sharp temperature decrease towards a minimum below 50 K, levelling off at higher values, reaching Hc = 200 Oe at 300 K. Annealing of FeAu results in a double-peak zero field cooled magnetization and a slight decrease of the coercivity. The interpretation of the results supports the presence of Fe nanoparticles embedded in the major noble matrix, with some diluted Fe atoms/clusters.