Field emission properties of carbon nanotube arrays grown in porous anodic alumina

AbstractCarbon nanotubes (CNTs), with their excellent electronic properties and extremely high aspect ratio, represent an ideal material for building electron sources based on field emission. Fowler‐Nordheim equation describes quite successfully the field emission phenomenon, especially for single or isolated tips. However, some complications arise when populations of CNTs are considered, where collective effects and large variability in the emitters features influence the measured I–V characteristics. In this work, the emission properties of multi‐walled CNTs grown within ordered anodic alumina templates are investigated. These CNT matrices produce current densities up to some tens of mA/cm2, and the field enhancement factor for collective emission sources can be estimated. Such material can be modelled as an ordered and uniform array of emitters and a simulation of the electrostatic field on the emission tips can be done in order to evaluate the field enhancement factor and its dependence on various geometries. This allows comparing predictions from simulation and experimental measurements, in a direct way. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim

SARS-CoV-2 Omicron BA.1 variant infection of human colon epithelial cells

The Omicron variant of SARS-CoV-2, characterized by multiple subvariants including BA.1, XBB.1.5, EG.5, and JN.1, became the predominant strain in early 2022. Studies indicate that Omicron replicates less efficiently in lung tissue compared to the ancestral strain. However, the infectivity of Omicron in the gastrointestinal tract is not fully defined, despite the fact that 70% of COVID-19 patients experience digestive disease symptoms. Here, using primary human colonoids, we found that, regardless of individual variability, Omicron infects colon cells similarly or less effectively than the ancestral strain or the Delta variant. The variant induced limited type III interferon expression and showed no significant impact on epithelial integrity. Further experiments revealed inefficient cell-to-cell spread and spike protein cleavage in the Omicron spike protein, possibly contributing to its lower infectious particle levels. The findings highlight the variant-specific replication differences in human colonoids, providing insights into the enteric tropism of Omicron and its relevance to long COVID symptoms

Human papillomavirus 9-valent vaccine for cancer prevention: a systematic review of the available evidence.

In 2014, the Food and Drug Administration approved a new human papillomavirus 9-valent vaccine (9vHPV), targeting nine HPV types: HPV types 6, 11, 16, and 18, which are also targeted by the quadrivalent HPV vaccine (qHPV), plus five additional high cancer risk HPV types (HPV types 31, 33, 45, 52, and 58). The aim of the current study was to systematically retrieve, qualitatively and quantitatively pool, as well as critically appraise all available evidence on 9vHPV from randomized controlled trials (RCTs). We conducted a systematic review of the literature on 9vHPV efficacy, immunogenicity and safety, as well as a systematic search of registered, completed, and ongoing RCTs. We retrieved and screened 227 records for eligibility. A total of 10 publications reported on RCTs' results on 9vHPV and were included in the review. Sixteen RCTs on 9vHPV have been registered on RCT registries. There is evidence that 9vHPV generated a response to HPV types 6, 11, 16 and 18 that was non-inferior to qHPV. Vaccine efficacy against five additional HPV type-related diseases was directly assessed on females aged 16-26 years (risk reduction against high-grade cervical, vulvar or vaginal disease = 96·7%, 95% CI 80·9%-99·8%). Bridging efficacy was demonstrated for males and females aged 9-15 years and males aged 16-26 years (the lower bound of the 95% CIs of both the geometric mean titer ratio and difference in seroconversion rates meeting the criteria for non-inferiority for all HPV types). Overall, 9vHPV has been proved to be safe and well tolerated. Other RCTs addressed: 9vHPV co-administration with other vaccines, 9vHPV administration in subjects that previously received qHPV and 9vHPV efficacy in regimens containing fewer than three doses. The inclusion of additional HPV types in 9vHPV offers great potential to expand protection against HPV infection. However, the impact of 9vHPV on reducing the global burden of HPV-related disease will greatly depend on vaccine uptake, coverage, availability, and affordability

Physiologic variations of gastrin in serum of German shepherd dog

Gastrin is a pool of peptide hormones at different molecular weight secreted by gastric and duodenal mucosa during feeding and involved in the intake of proteins. Aim of present study was to establish the gastrin concentration in serum samples of 40 healthy German shepherd dogs belonging to 5 different age groups. A RIA commercial kit has been used, which has been validated for the animal species under study with preliminary dose-response experiments. Results obtained showed specificity of the procedure used for canine gastrin. The obtained reference range (14.6-61.8 pg/ml) resulted to be superimposable to the range reported in literature for italian mongrel dogs (15- 78.6 pg/ml). No differences related to sex have been observed (females 38.2 + 10.4 pg/ml males 38.2 + 12.7 pg/ml). The gastrin concentration resulted to be elevated in puppies aged 3-3.5 months (58 pg/ml) and stabilized in dogs from 7 months to 10 years on values ranging 27-33 pg/ml. Physiological and pathological role of this hormone is discussed. This study supports the critical evaluation of pathological variations of gastrin in serum of the dogs

Characteristic Mode Analysis of Multi-Octave Asymmetric Dipoles

This paper discusses the impedance and front-to-back ratio performance of asymmetric dipoles. These parameters are very important when the antennas are placed over a conductive ground plane and should operate over multi-octave frequency bands. The operation of these antennas is usually described relying on analogies with more classical structures such as symmetric dipoles and tapered slot antennas. To provide a solid theoretical background to this intuition, this work presents the application of characteristic mode analysis to multi-octave dipole antennas. Firstly, a brief review of the main characteristic mode content is presented. Then, characteristic mode analysis is applied to three antenna concepts to emphasize how their geometry impacts on the relevant figures of merit. This allows to draw some conclusions on the achievable performance by different designs

First Results on the Experimental Validation of the SKA-low Prototypes Deployed in Australia Using an Airborne Test Source

As the Square Kilometre Array progresses toward the construction phase, the first prototypes of the low-frequency instrument have been deployed in Australia. To support such a crucial phase, a measurement campaign took place in the Murchison Radio-astronomy Observatory area in order to validate the electromagnetic models of the arrays by characterizing the embedded-element patterns and the array beams. A set of significant results is shown in this contribution

A prototype model for evaluating SKA-LOW station calibration

The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log periodic dual polarized antennas each (where each group is called “station”), for a total of 131072 antennas. The 512 stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having 16 station clusters each. In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array (MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic challenges typical of a deployment of the actual telescope. The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA: Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme. All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5 station are presented. The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the calibration quality and the technological maturity of the future SKA1-Low array

Dolore post-operatorio nei pazienti affetti da neoplasia testa-collo: fattori predittivi ed efficacia della terapia

Negli anni è aumentata l’attenzione verso i molteplici aspetti associati alla “sfera” dolore, anche nei pazienti oncologici sottoposti a chirurgia testa-collo. Il dolore, definito infatti da diverse caratteristiche, quali l’esperienza personale, gli aspetti qualitativi della percezione, l’intensità, l’impatto emotivo, riconosce un’eziologia “multifattoriale”. Scopo del presente lavoro è stato: (i) valutare l’efficacia della terapia analgesica in pazienti affetti da tumore testa-collo e sottoposti a trattamento chirurgico; (ii) studiare le possibili variabili ed i fattori predittivi che possano influenzare l’insorgenza di dolore. Sono stati studiati 164 pazienti, affetti da neoplasia maligna del distretto testa-collo, trattati chirurgicamente tra il dicembre 2009 ed il dicembre 2013. I dati raccolti comprendono l’età, il sesso, la valutazione del rischio anestesiologico, la sede del tumore, la stadiazione TNM, il tipo di intervento effettuato, la complessità e la durata dell’intervento, le eventuali complicanze post-operatorie, i giorni di degenza post-intervento, la valutazione del dolore nei giorni 0, 1, 3 e 5 post-chirurgia. L’adeguatezza della terapia analgesica è stata espressa in termini di incidenza e prevalenza del dolore post-operatorio, le variabili legate al paziente, alla malattia, al trattamento chirurgico e farmacologico, sono state poi associate all’insorgenza del dolore così da poter descrivere eventuali fattori predittivi. Dai dati ottenuti emerge che la popolazione studiata ha ricevuto un’adeguata terapia antalgica, sia nell’immediato post-operatorio che nei giorni successivi. Non sono risultate associazioni statisticamente significative tra sesso, età ed incidenza del dolore post-chirurgico, mentre lo stadio del tumore, la complessità dell’intervento chirurgico e la sede della neoplasia hanno presentano correlazione significativa con il rischio di insorgenza di dolore post-operatorio. L’elevata prevalenza del dolore in ambito oncologico testa-collo, fa sì che un’appropriata ed attenta gestione del dolore risulti fondamentale. Nel futuro pertanto si auspica una sempre migliore comprensione dei fattori biologici, sociali e psicologici che caratterizzano la percezione del dolore ai fini di migliorarne il controllo