Terahertz electric-field-driven dynamical multiferroicity in SrTiO3.

The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention1-6. The theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization due to time-dependent electric polarization in non-ferromagnetic materials7,8. In simple terms, the coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. Here we provide experimental evidence of room-temperature magnetization in the archetypal paraelectric perovskite SrTiO3 due to this mechanism. We resonantly drive the infrared-active soft phonon mode with an intense circularly polarized terahertz electric field and detect the time-resolved magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab initio calculations using self-consistent phonon theory at a finite temperature9, reproduces qualitatively our experimental observations. A quantitatively correct magnitude was obtained for the effect by also considering the phonon analogue of the reciprocal of the Einstein-de Haas effect, which is also called the Barnett effect, in which the total angular momentum from the phonon order is transferred to the electronic one. Our findings show a new path for the control of magnetism, for example, for ultrafast magnetic switches, by coherently controlling the lattice vibrations with light.

Extreme ultraviolet transient gratings: A tool for nanoscale photoacoustics.

Collective lattice dynamics determine essential aspects of condensed matter, such as elastic and thermal properties. These exhibit strong dependence on the length-scale, reflecting the marked wavevector dependence of lattice excitations. The extreme ultraviolet transient grating (EUV TG) approach has demonstrated the potential of accessing a wavevector range corresponding to the 10s of nm length-scale, representing a spatial scale of the highest relevance for fundamental physics and forefront technology, previously inaccessible by optical TG and other inelastic scattering methods. In this manuscript we report on the capabilities of this technique in the context of probing thermoelastic properties of matter, both in the bulk and at the surface, as well as discussing future developments and practical considerations.

Ultrafast Amplification and Nonlinear Magnetoelastic Coupling of Coherent Magnon Modes in an Antiferromagnet.

We investigate the role of domain walls in the ultrafast magnon dynamics of an antiferromagnetic NiO single crystal in a pump-probe experiment with variable pump photon energy. Analyzing the amplitude of the energy-dependent photoinduced ultrafast spin dynamics, we detect a yet unreported coupling between the material's characteristic terahertz- and gigahertz-magnon modes. We explain this unexpected coupling between two orthogonal eigenstates of the corresponding Hamiltonian by modeling the magnetoelastic interaction between spins in different domains. We find that such interaction, in the nonlinear regime, couples the two different magnon modes via the domain walls and it can be optically exploited via the exciton-magnon resonance.

Nanopatterning reconfigurable magnetic landscapes via thermally assisted scanning probe lithography.

The search for novel tools to control magnetism at the nanoscale is crucial for the development of new paradigms in optics, electronics and spintronics. So far, the fabrication of magnetic nanostructures has been achieved mainly through irreversible structural or chemical modifications. Here, we propose a new concept for creating reconfigurable magnetic nanopatterns by crafting, at the nanoscale, the magnetic anisotropy landscape of a ferromagnetic layer exchange-coupled to an antiferromagnetic layer. By performing localized field cooling with the hot tip of a scanning probe microscope, magnetic structures, with arbitrarily oriented magnetization and tunable unidirectional anisotropy, are reversibly patterned without modifying the film chemistry and topography. This opens unforeseen possibilities for the development of novel metamaterials with finely tuned magnetic properties, such as reconfigurable magneto-plasmonic and magnonic crystals. In this context, we experimentally demonstrate spatially controlled spin wave excitation and propagation in magnetic structures patterned with the proposed method.

Enhanced Magneto-Optical Edge Excitation in Nanoscale Magnetic Disks.

We report unexpected enhancements of the magneto-optical effect in ferromagnetic Permalloy disks of diameter D<400 nm. The effect becomes increasingly pronounced for smaller D, reaching more than a 100% enhancement for D=100 nm samples. By means of experiments and simulations, the origin of this effect is identified as a nanoscale ring-shaped region at the disk edges, in which the magneto-optically induced electric polarization is enhanced. This leads to a modification of the electromagnetic near fields and causes the enhanced magneto-optical excitation, independent from any optical resonance.

Recurrent pneumococcal meningitis in a child with transethmoidal encephalocele: a case report and review of literature.

Bacterial meningitis is a life-threatening infection with a low recurrence rate. However, this possibility has always to be considered and avoided. This case report concerns a 5-year-old girl who was admitted in our Emergency Pediatric Unit for symptoms of bacterial meningitis and signs of disseminated intra-vascular coagulopathy. After a successful treatment the girl was discharged in good health. She was admitted to our hospital after one year with the same symptoms of meningitis. Laboratory examinations confirm the admittance suspect. An accurate research allowed to find out immunological deficiencies and showed an occult malformation, transethmoidal encephalocele, responsible for the recurrent meningitis. The present case suggests that the opportunity to perform an accurate cerebral imaging study (with special attention to the ethmoidal region and inner ear) in all cases of meningitis to detect occult anatomical alterations, thus preventing infectious recurrence, should always be taken into account.

[The short-stay observation unit: an experience of the Pediatric Department in Modena]. / Osservazione breve intensiva (OBI) in pediatria: l'esperienza del Policlinico di Modena.

The use of a short-stay observation unit (OBI) in a pediatric department has reduced the number of admissions. Significant cost savings and a better care for children and their families have been also achieved. During the year 2003 in our department 1759 children received OBI. 226 (12.8%) were then admitted. 1553 (87.2%) were discharged after a nine-hour mean stay. Descriptive statistics are used to outline the sample of patients and used treatments.

Microsatellite DNA in peach (Prunus persica L. Batsch) and its use in fingerprinting and testing the genetic origin of cultivars.

We isolated and sequenced 26 microsatellites from two genomic libraries of peach cultivar 'Redhaven', enriched for AC/GT and AG/CT repeats, respectively. For 17 of these microsatellites, it was possible to demonstrate Mendelian inheritance. Microsatellite polymorphism was assayed in 50 peach and nectarine cultivars. Of the 1300 PCRs carried out, all but two produced amplified products of the expected size. All microsatellites were polymorphic, showing 2-8 alleles per locus. Heterozygosity ranged from 0.04-0.74 (mean 0.47); the discrimination power (PD) ranged from 0.04-0.84 (mean 0.60). Cultivar heterozygosity varied greatly, with one cultivar ('Independence') being homozygous at all loci. The set of microsatellites discriminated all cultivars investigated, except several sport mutations, i.e., 'Dixitime' vs. 'Springcrest', 'Compact Redhaven' vs. 'Redhaven', and two pairs of cultivars, 'Venus' vs. 'Orion' and 'Elegant Lady' vs. 'Rome Star', whose pedigrees are controversial. We were able to analyze the paternity of several cultivars. In most cases, the parenthood was confirmed. The comparison of three long-living 'Redhaven' accessions supplied by different repositories did not provide any evidence of somatic instability of microsatellites. Hence, microsatellites, ranked according to their information content, are recommended as markers of choice for peach fingerprinting and suggestions are provided for interpreting band profiles and the correct sizing of alleles.

[Helicobacter pylori. Part II. Epidemiology, diagnosis, and treatment]. / Helicobacter Pylori. IIa Parte: Epidemiologia, diagnosi e terapia.

In recent years, the diagnosis of Helicobacter Pylori (HP)-mediated infection has become increasingly important not only in adults but also in children. Factors such as residence in a country with low social and economic standards and the presence of HP-positive family members underscore the widely-acknowledged fact that the incidence of HP infection tends to increase with age both in children (where the increase is roughly 1% per year) and in adults, where it reaches values of 50% in the industrialized nations and 80% in developing countries. This has led to research aimed at developing more accurate and less invasive diagnostic techniques that can be used in children as well. Also, the development of simple, cost-effective diagnosis is all the more important given the widespread occurrence of HP infection, particularly in the developing countries. The techniques employed range from the classical histological and culture examination, which involves esophagogastroduodenoscopy (a rather invasive technique), to serology and the Urea Breath Test with 13C. Also, the feasibility of tracing HP antigens in the faeces, a non-invasive and simple technique, is under investigation. As for therapy, there is as yet no unanimous agreement about when to start treatment, about which antibiotics (beta-lactams, macrolides and nitro-imidazoles) to use in association, about their effect on the gastric mucosa, nor, indeed, about the treatment routines to be followed in adults and children.

[A case of female pseudohermaphroditism caused by maternal androluteoma]. / Caso di pseudoermafroditismo femminile da androluteoma materno.

Female pseudohermaphroditism is a condition characterized by various degree of external genitalia virilization in a patient with female internal genitalia and karyotype (XX). External genitalia is masculinized congenitally when female fetus is exposed to excess androgenic environment. Fetal metabolic abnormalities, like congenital adrenal hyperplasia, are the most common causes of female pseudohermaphroditism, however there is a low incidence of gestational hyperandrogenism caused by maternal pathology. We report a case of female pseudohermaphroditism secondary to a maternal ovarian luteoma of pregnancy producing androgenic hormones. The newborn presented a severe degree of external genitalia virilization with high urogenital sinus (stage Prader V). Moreover we describe the main steps of diagnostic iter that are necessary both to exclude other causes of virilization and to study all anatomical aspects in view of the surgical correction. The operation consists in two phases of action: an early clitorisvulvoplasty according to Passerini-Glazel and a late vaginal pull-through with anterior saggital transanorectal approach (ASTRA).

[Neonatal cystic fibrosis: report of 2 cases]. / Fibrosi Cistica ad esordio neonatale: descrizione di due casi.

Cystic fibrosis is the most common life-limiting recessive genetic disorder in Caucasian. It is caused by mutations of CFTR gene (cystic fibrosis transmembrane conductance regulator); at present over 500 mutations are known. Cystic fibrosis as a cause of respiratory distress in the neonate is quite rare. In neonatal period the most important clinical manifestations are meconium ileum and much rarely cholestatic jaundice. We present two cases of cystic fibrosis in newborns. In the first one, we point out the strict association between meconium ileum and cystic fibrosis. The patient underwent a surgical treatment for meconium ileum and the diagnosis was rapidly confirmed by genetic analysis and sweat test. The second one had intestinal obstruction from birth caused by meconium ileum associated with ileal atresia; besides, he developed cholestatic jaundice, severe and rapidly progressive respiratory disease. He died at 102 degrees day of age for cardiac failure. The diagnosis of cystic fibrosis, supported by typical clinical features and high level of serum trypsin, unfortunately wasn't confirmed by genetic analysis (lambda F508/neg), in addition, the sweat test wasn't reliable because an inadequate quantity of sweat was collected.

[Helicobacter pylori. I. Morphology, biochemistry, antigenic profile and correlated diseases]. / Helicobacter pylori. I. Parte: Morfologia, biochimica, profilo antigenico e patologie correlate.

Infection by Helicobacter pylori (HP) occurs all over the world and is related to the socio-economic development of the subject's country of residence and age. Various strains of HP can be identified on the basis of the microbiological characteristics of the bacterium and, in particular, or its antigenic profile, while the virulence factors are responsible for the damage that HP can cause. The virulence factors include components (flagellum and adhesin) and substances produced by bacterium (enzymes and cytotoxins), the most important among which are urease and the cytotoxins, CagA and VacA. It is the association of these virulence factors that is responsible for the different pathologies to which HP-positive subjects are prone. The link between HP and gastritis, peptic ulcer and gastric cancers (adenocarcinoma and lymphoma) is now proven. Whether there is a link between HP and RAP in young children is still a matter for debate; some Authors claim that there is, while others refute it.