Selection rules for the orbital angular momentum of optically produced THz radiation.

In this work, we theoretically study the transduction of orbital angular momentum (OAM) l for infrared pump lasers into the THz domain. In the case of optical rectification, the transduction of OAM occurs only through a spin-orbit interaction, with the selection rule on the OAM l=0 valid for any kind of polarization of the pump, which means that there is no transfer of OAM along the propagation axis. In difference frequency generation, the selection rule for the difference Δl between the OAM of the pump fields with linear or circular polarization is l=Δl, whereas l ranges from Δl-2 to Δl+2 in cases of both radial and azimuthal polarization. Moreover, for THz generation in the latter case, the high diffraction obtained with tightly focused pumps yields l tending to Δl±2, while l tends to zero in the opposite case of large pump beams.

A cryogenic magneto-optical device for long wavelength radiation.

We present here a small-scale liquid helium immersion cryostat with an innovative optical setup suitable to work in long wavelength radiation ranges and under an applied magnetic field. The cryostat is a multi-stage device with several shielding in addition to several optical stages. The system has been designed with an external liquid nitrogen boiler to reduce liquid bubbling. The optical and mechanical properties of the optical elements were calculated and optimized for the designed configuration, while the optical layout has been simulated and optimized among different configurations based on the geometry of the device. The final design has been optimized for low-noise radiation measurements of proximity junction arrays under an applied magnetic field in the wavelength range λ = 250 µm-2500 µm.

Terahertz Tuning of Dirac Plasmons in Bi_{2}Se_{3} Topological Insulator.

Light can be strongly confined in subwavelength spatial regions through the interaction with plasmons, the collective electronic modes appearing in metals and semiconductors. This confinement, which is particularly important in the terahertz spectral region, amplifies light-matter interaction and provides a powerful mechanism for efficiently generating nonlinear optical phenomena. These effects are particularly relevant in graphene and topological insulators, where massless Dirac fermions show a naturally nonlinear optical behavior in the terahertz range. The strong interaction scenario has been considered so far from the point of view of light. In this Letter, we investigate instead the effect of strong interaction on the plasmon itself. In particular, we will show that Dirac plasmons in Bi_{2}Se_{3} topological insulator are strongly renormalized when excited by high-intensity terahertz radiation by displaying a huge red-shift down to 60% of its characteristic frequency. This opens the road towards tunable terahertz nonlinear optical devices based on topological insulators.

Long-term persistency of hepatitis B immunity: an observational cross-sectional study on medical students and resident doctors.

Hepatitis B virus (HBV) is a main cause of chronic and acute hepatitis. Healthcare workers (HCWs), including medical students and resident doctors, have an occupational risk of HBV infection. The study aimed to evaluate the long-term persistence of protective anti-HBs antibody levels in healthcare students and resident doctors at risk for occupational exposure to HBV at 15 years after primary vaccination course. Further objective was to evaluate the anamnestic response observed in non-seroprotected subjects receiving a booster dose. Data were collected from the clinical documentation filled in during the occupational medical check of medical students and resident doctors undergoing Occupational Health Surveillance by the University of Ferrara. Of the 621 included individuals, 27.7% had an anti-HBs concentration < 10 mIU/mL. Subjects vaccinated during infancy had more frequently a concentration < 10 mIU/mL than those vaccinated during adolescence (42.7% vs 6.9%; p-value < 0.001). Multivariate analysis confirmed the statistical significance of the vaccination age. 94 subjects who had an anti-HBs concentration < 10 mIU/mL received a booster dose. The proportion of subjects who had an anamnestic response was higher in those vaccinated in infancy rather than during adolescence (94.1% vs 77.8% respectively). These findings suggest that the anti-HBs concentration decreases below 10 mIU/mL more frequently in subjects vaccinated during infancy. Immunological memory seems to persist after the decline of the anti-HB titer, as observed in response to a booster dose. In conclusion, vaccinated subjects at increased risk of HBV infection should be monitored and a booster dose administered if anti-HBs titer is below 10 mIU/mL.

Author Correction: Resonant plasma excitation by single-cycle THz pulses.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Enfoque diagnóstico de feocromocitomas y paragangliomas / Diagnostic approach of pheochromocytomas and paragangliomas

Los feocromocitomas y paragangliomas son tumores neuroendócrinos poco frecuentes y con alta morbimortalidad. Reconocer las distintas formas de presentación es el paso diagnóstico inicial. El estudio bioquímico permite determinar el exceso de catecolaminas y sus metabolitos. Sin embargo, las determinaciones disponibles ofrecen diferente precisión diagnóstica. La tomografía computada y la resonancia magnética permiten localizar estos tumores con una alta sensibilidad. Los estudios funcionales se reservan para sospecha de enfermedad metastásica y para tumores múltiples. Un tercio de los pacientes presenta una mutación genética germinal y varios genes están implicados en el desarrollo de estos tumores

Pheochromocytomas and paragangliomas are rare neuroendocrine tumours associated with high morbidity and mortality. Recognizing the clinical presentation is the first step for diagnosis. Biochemical studies may determine an excess of catecholamines and their metabolites. However, the available tests offer varying diagnosis precision. Computed tomography and magnetic resonance are highly sensitive for locating these tumours. Functional tests are reserved for when metastatic and multifocal disease are suspected. One third of the patients have a germline mutation and many genes are involved in the development of these tumours

[Diagnostic approach of pheochromocytomas and paragangliomas]. / Enfoque diagnóstico de feocromocitomas y paragangliomas.

Pheochromocytomas and paragangliomas are rare neuroendocrine tumours associated with high morbidity and mortality. Recognizing the clinical presentation is the first step for diagnosis. Biochemical studies may determine an excess of catecholamines and their metabolites. However, the available tests offer varying diagnosis precision. Computed tomography and magnetic resonance are highly sensitive for locating these tumours. Functional tests are reserved for when metastatic and multifocal disease are suspected. One third of the patients have a germline mutation and many genes are involved in the development of these tumours.

Coherent THz Emission Enhanced by Coherent Synchrotron Radiation Wakefield.

We demonstrate that emission of coherent transition radiation by a ∼1 GeV energy-electron beam passing through an Al foil is enhanced in intensity and extended in frequency spectral range, by the energy correlation established along the beam by coherent synchrotron radiation wakefield, in the presence of a proper electron optics in the beam delivery system. Analytical and numerical models, based on experimental electron beam parameters collected at the FERMI free electron laser (FEL), predict transition radiation with two intensity peaks at ∼0.3 THz and ∼1.5 THz, and extending up to 8.5 THz with intensity above 20 dB w.r.t. the main peak. Up to 80-µJ pulse energy integrated over the full bandwidth is expected at the source, and in agreement with experimental pulse energy measurements. By virtue of its implementation in an FEL beam dump line, this work promises dissemination of user-oriented multi-THz beamlines parasitic and self-synchronized to EUV and x-ray FELs.

Terahertz-based retrieval of the spectral phase and amplitude of ultrashort laser pulses.

Terahertz (THz) radiation is of great interest for a variety of applications, e.g., particle accelerations, spectroscopy investigations of quantum systems, and high-field study of materials. One of the most common laser-based processes to produce THz pulses is optical rectification, which transduces an infrared pump laser to the THz domain (0.1-20 THz). In this work, we propose and theoretically describe a method to characterize the amplitude and phase of the electric field of the pump laser pulse relying on THz generation and detection. We demonstrate with a numerical example how THz radiation can be used as diagnostics to characterize laser pulses with temporal length at the femtosecond level.

Resonant plasma excitation by single-cycle THz pulses.

In this paper, an alternative perspective for the generation of millimetric high-gradient resonant plasma waves is discussed. This method is based on the plasma-wave excitation by energetic single-cycle THz pulses whose temporal length is comparable to the plasma wavelength. The excitation regime discussed in this paper is the quasi-nonlinear regime that can be achieved when the normalized vector potential of the driving THz pulse is on the order of unity. To investigate this regime and determine the strength of the excited electric fields, a Particle-In-Cell (PIC) code has been used. It has been found that by exploiting THz pulses with characteristics currently available in laboratory, longitudinal electron plasma waves with electric gradients up to hundreds MV/m can be obtained. The mm-size nature of the resonant plasma wave can be of great utility for an acceleration scheme in which high-brightness electron bunches are injected into the wave to undergo a strong acceleration. The long-size nature of the acceleration bucket with respect to the short length of the electron bunches can be handled in a more robust manner in comparison with the case when micrometric waves are employed.

Identifying Ferrara's elderly people with low influenza immunization rates: the contribution of a local socio-economic deprivation index.

Influenza immunization coverage rates remain far below the optimal value recommended by the World Health Organization, even in groups considered at high risk, such as the elderly. A possible explanation for this suboptimal vaccination uptake may be deprivation. A specifically developed local deprivation index was proposed for the classification of residents in the municipality of Ferrara in order to evaluate the characteristics of subjects over 65 years of age who accepted/refused influenza immunization (2010-2015). The variables building this deprivation index were primarily related to demographic aspects, such as age, widow/widower status, education, family composition and housing characteristics. Influenza immunization coverage rates were unsatisfactory in all categories of deprivation. A statistically significant decreasing trend in coverage rates was observed with decreasing deprivation in the general population and in males, but not in females. In addition to factors composing the local deprivation index, being separated, living in a family of three members and independent contractor were features that hindered immunization among very deprived elderly.

Knowledge and behaviour of nursing students on the prevention of healthcare associated infections.

INTRODUCTION: Hospital infections, or "healthcare associated infections" (HAI) represent the most common and serious complications of healthcare. Adoption of safe care practices able to prevent or control the transmission of infections, both in hospitals and in other healthcare settings is crucial. The aim of the study is to assess the awareness about the risk factors and the most effective measures of prevention of HAI in the University of Ferrara nursing school students, giving particular attention to the hand hygiene practices and the use of standard precautions. METHODS: 339 students attending all the three years of course of the same academic year were enrolled. An anonymous questionnaire was administered in order to investigate the knowledge about three specific areas: infections associated with healthcare practices (HAI), standard precautions (SP) and hand hygiene (HH). RESULTS: A sufficient level of knowledge by all the three groups of students was observed only in the SP area. A barely sufficient score was reached only by the third year students with regard to the proper HH. The level of knowledge about HAI was inadequate. CONCLUSIONS: A periodically check of nursing students' knowledge would be advisable in order to fill any gaps, improve training, reduce HAI and increase prevention measures compliance.

Mottness at finite doping and charge-instabilities in cuprates.

The influence of the Mott physics on the doping-temperature phase diagram of copper oxides represents a major issue that is subject of intense theoretical and experimental effort. Here, we investigate the ultrafast electron dynamics in prototypical single-layer Bi-based cuprates at the energy scale of the O-2p→Cu-3d charge-transfer (CT) process. We demonstrate a clear evolution of the CT excitations from incoherent and localized, as in a Mott insulator, to coherent and delocalized, as in a conventional metal. This reorganization of the high-energy degrees of freedom occurs at the critical doping pcr ≈0.16 irrespective of the temperature, and it can be well described by dynamical mean field theory calculations. We argue that the onset of the low-temperature charge instabilities is the low-energy manifestation of the underlying Mottness that characterizes the p < pcr region of the phase diagram. This discovery sets a new framework for theories of charge order and low-temperature phases in underdoped copper oxides.

Orbital dependent coherence temperature and optical anisotropy of V2O3 quasiparticles.

We report on an orbital and temperature dependent study of the onset of coherent quasiparticles in V2O3 single crystal. By using polarized infrared spectroscopy we demonstrate that the electronic coherence temperature is strongly orbital dependent, being about 400 K for [Formula: see text] orbitals and 500 K for the [Formula: see text]. This suggests that V2O3 low energy electrodynamics can be described in terms of two electron liquids differently renormalized by electronic correlations.

Ensayo clínico de eficacia del bloqueo bloqueo del plano transverso del abdomen ecoguiado en la histerectomía laparoscópica / Efficacy of ultrasound-guided transversus abdominis plane block in laparoscopic hysterectomy. Clinical trial

Objetivos. El bloqueo del plano transverso abdominal es una técnica de anestesia regional que demostró ser efectiva en cirugía abdominal abierta y laparoscópica como parte de un esquema de tratamiento del dolor postoperatorio. La presente investigación evaluó su eficacia en cirugía de histerectomía total laparoscópica. Materiales y métodos. El estudio fue diseñado como un ensayo clínico controlado, aleatorizado en 2 ramas: grupo protocolo bloqueo del plano transverso abdominal+analgesia intravenosa (Grupo 1; n=20) versus grupo protocolo analgesia intravenosa (Grupo 2; n=20), simple ciego que incluyó a 40 pacientes sometidas a una histerectomía total laparoscópica programada. Consumo de opioides en las primeras 24h del postoperatorio (mg de morfina), intensidad del dolor por escala verbal numérica a los 60min, 2, 8 y 24h posteriores a la cirugía, efectos adversos relacionados con la medicación administrada, calidad del sueño en la primera noche poscirugía y tiempo hasta el alta hospitalaria fueron evaluados y registrados. Resultados. No hubo diferencias estadísticamente significativas entre ambos grupos en cuanto al consumo de opioides (10mg vs. 7mg; p=0,2) y en las escalas de dolor por EVN postoperatorias a los 60min (3 vs. 5; p=0,65), 120min (0 vs. 2; p=0,15), 8 y 24h (0 vs. 0; p>0,50), en estos 2 últimos puntos de tiempo evaluados. Tampoco se hallaron diferencias respecto a la incidencia de efectos adversos, calidad de sueño en la primera noche después de la cirugía ni en el tiempo hasta el alta hospitalaria. Conclusiones. El bloqueo del plano transverso abdominal parece no aportar ningún beneficio adicional respecto a un plan de analgesia con opioides tipo PCA empleado en cirugía laparoscópica ginecológica, prolongando los tiempos de preparación del paciente, agregando un riesgo eventual (aunque bajo) de complicaciones e incrementando los costos (AU)

Objectives. Transversus abdominis plane block is a regional anaesthesia technique that has proven to be effective for postoperative pain reduction in different abdominal surgical procedures. This study evaluated its efficacy on post laparoscopic hysterectomy pain intensity and analgesic consumption. Materials and methods. Randomized controlled trial which included 40 patients scheduled for laparoscopic hysterectomy, enrolled in 2 groups: transversus abdominis plane block+systemic analgesia (Group 1; n=20), versus systemic analgesia (Group 2; n=20). Opioid consumption within the first 24 postoperative hours, pain intensity scores at 60min, 2, 8 and 24h after surgery, adverse events related to systemic analgesia and time to hospital discharge were evaluated and registered. Results. We found no differences between both groups in opioid consumption (10mg vs. 7mg; P=.2) and pain scores (NVS) within the first 24 postoperative hours, at 60min (3 vs. 5; P=.65), 120min (0 vs. 2; P=.15), 8 and 24h (0 vs. 0; P>.50) for the last 2 points in time analysed. Adverse events related to medication and time to hospital discharge showed similar results. Conclusions. Adding a transversus abdominis plane block technique to opioid PCA does not seem to improve postoperative pain management in laparoscopic hysterectomy. Patient preparation time and costs could be incremented and complications (although rare) related to the technique could appear (AU)

Terahertz plasmonic excitations in Bi2Se3 topological insulator.

After the discovery of Dirac electrons in condensed matter physics, more specifically in graphene and its derivatives, their potentialities in the fields of plasmonics and photonics have been readily recognized, leading to a plethora of applications in active and tunable optical devices. Massless Dirac carriers have been further found in three-dimensional topological insulators. These exotic quantum systems have an insulating gap in the bulk and intrinsic Dirac metallic states at any surface, sustaining not only single-particle excitations but also plasmonic collective modes. In this paper we will review the plasmon excitations in different microstructures patterned on Bi2Se3 topological insulator thin films as measured by terahertz spectroscopy. We discuss the dependence of the plasmon absorption versus the microstructure shape, wavevector, and magnetic field. Finally we will discuss the topological protection of both the Dirac single-particle and plasmon excitations.

Efficacy of ultrasound-guided transversus abdominis plane block in laparoscopic hysterectomy. Clinical trial. / Ensayo clínico de eficacia del bloqueo bloqueo del plano transverso del abdomen ecoguiado en la histerectomía laparoscópica.

OBJECTIVES: Transversus abdominis plane block is a regional anaesthesia technique that has proven to be effective for postoperative pain reduction in different abdominal surgical procedures. This study evaluated its efficacy on post laparoscopic hysterectomy pain intensity and analgesic consumption. MATERIALS AND METHODS: Randomized controlled trial which included 40 patients scheduled for laparoscopic hysterectomy, enrolled in 2 groups: transversus abdominis plane block+systemic analgesia (Group 1; n=20), versus systemic analgesia (Group 2; n=20). Opioid consumption within the first 24 postoperative hours, pain intensity scores at 60min, 2, 8 and 24h after surgery, adverse events related to systemic analgesia and time to hospital discharge were evaluated and registered. RESULTS: We found no differences between both groups in opioid consumption (10mg vs. 7mg; P=.2) and pain scores (NVS) within the first 24 postoperative hours, at 60min (3 vs. 5; P=.65), 120min (0 vs. 2; P=.15), 8 and 24h (0 vs. 0; P>.50) for the last 2 points in time analysed. Adverse events related to medication and time to hospital discharge showed similar results. CONCLUSIONS: Adding a transversus abdominis plane block technique to opioid PCA does not seem to improve postoperative pain management in laparoscopic hysterectomy. Patient preparation time and costs could be incremented and complications (although rare) related to the technique could appear.

Air-abrasive debridement with glycine powder versus manual debridement and chlorhexidine administration for the maintenance of peri-implant health status: a six-month randomized clinical trial.

STUDY DESIGN: This single-masked, randomized and six-month clinical intervention trial including two study groups was planned to evaluate the efficacy of maintenance treatment with glycine powder on the periodontal health of peri-implant tissues. METHODS: A total of 46 patients with partial or total edentulism, carrying a total of 88 implants, were assigned either to an air abrasive with the glycine powder treatment group (AAD) or to a manual debridement and clorexidine administration treatment group (MDA). Clinical data were collected before treatment and at 3 and 6 months after the treatment. Plaque index (PI), bleeding index (BOP), probing depth (PD), clinical attachment level (CAL) and bleeding score (BS) were analysed. RESULTS: After 3 months, AAD treatment statistically significantly improved BS (P < 0.05); at 6 months, AAD treatment statistically significantly improved indexes PD, PI, BOP and BS (P < 0.05). In addition, the AAD treatment proved to be more effective than MDA in maintaining the peri-implant health of PD at three and 6 months, and of PI at 6 months (P < 0.05). There were no significant changes of CAL in both groups, and all the indexes remained within the physiological levels. CONCLUSIONS: Within the limits of the study, treatment with glycine seems appropriate in the maintenance of peri-implant health and more effective than the traditional treatment with plastic curette and chlorhexidine.

Fermi Surface of Metallic V_{2}O_{3} from Angle-Resolved Photoemission: Mid-level Filling of e_{g}

Using angle resolved photoemission spectroscopy, we report the first band dispersions and distinct features of the bulk Fermi surface (FS) in the paramagnetic metallic phase of the prototypical metal-insulator transition material V_{2}O_{3}. Along the c axis we observe both an electron pocket and a triangular holelike FS topology, showing that both V 3d a_{1g} and e_{g}^{π} states contribute to the FS. These results challenge the existing correlation-enhanced crystal field splitting theoretical explanation for the transition mechanism and pave the way for the solution of this mystery.

Possible light-induced superconductivity in K3C60 at high temperature.

The non-equilibrium control of emergent phenomena in solids is an important research frontier, encompassing effects such as the optical enhancement of superconductivity. Nonlinear excitation of certain phonons in bilayer copper oxides was recently shown to induce superconducting-like optical properties at temperatures far greater than the superconducting transition temperature, Tc (refs 4-6). This effect was accompanied by the disruption of competing charge-density-wave correlations, which explained some but not all of the experimental results. Here we report a similar phenomenon in a very different compound, K3C60. By exciting metallic K3C60 with mid-infrared optical pulses, we induce a large increase in carrier mobility, accompanied by the opening of a gap in the optical conductivity. These same signatures are observed at equilibrium when cooling metallic K3C60 below Tc (20 kelvin). Although optical techniques alone cannot unequivocally identify non-equilibrium high-temperature superconductivity, we propose this as a possible explanation of our results.