Experimental Investigation of Helicopter Noise While Approaching an Elevated Helipad

The present paper describes a test campaign performed to investigate the noise footprint emitted by a helicopter in an idealised urban context, reproducing the approach to an elevated helipad. The test campaign was performed in Politecnico di Milano’s anechoic chamber and was finalised to investigate the effects produced only by helicopter noise. The set up consisted of a two-blade main rotor helicopter model and an aluminium rectangular prism model reproducing the landing building. Ground observer perceptions were recorded by means of a surface microphone and a realistic landing trajectory was approximated as a succession of fixed point measurements. Collected data were analysed through acoustic spectra and sound maps. Spectra were used to comprehend physical phenomena, such as reflection, diffraction and shielding, and to analyse the different contributions of helicopter noise. A sound map analysis enabled us to obtain a global perspective of the involved phenomena and to understand th extent to which people close to a building are stressed by a helicopter approaching an elevated urban helipad. Moreover, the experimental database, obtained over a free geometry, can be considered a useful tool for the validation of aeroacoustic solvers with different levels of fidelity

Surgical management of a life-threatening retro-pharyngeal haematoma following trans-oesophageal echocardiography = Trattamento chirurgico di un pericoloso ematoma retrofaringeo, sviluppatosi a seguito di un\u2019ecocardiografia transesofagea

Nonostante siano state descritte complicanze potenzialmente letali, l\u2019ecocardiografia transesofagea viene considerata una procedura diagnostica sicura. Scopo del presente lavoro \ue8 sottolineare come, nei casi di voluminosi ematomi secondari a tale procedura, possa diventare indispensabile il ricorso alla chirurgia per tutelare la vita del paziente. Nel caso qui descritto, un paziente affetto da spondilosi cervicale e in terapia anticoagulante ha sviluppato, a seguito di un\u2019ecocardiografia transesofagea, un ematoma retrofaringeo tanto voluminoso da determinare un\u2019ostruzione delle vie aeree superiori. Per assicurarne la perviet\ue0 \ue8 stato necessario ricorrere a una tracheotomia, l\u2019ematoma, invece, \ue8 stato drenato per via transcervicale. Il paziente \ue8 guarito completamente in 10 giorni. Il chirurgo otorinolaringoiatrico dovrebbe essere a conoscenza, non solo di questa rara complicanza, ma anche della necessit\ue0 di un suo trattamento chirurgico.Trans-oesophageal echocardiography is generally considered a safe procedure, but occasional life-threatening complications have been reported. The aim of this clinical investigation is to outline the need of surgical management in cases of large retro-pharyngeal haematoma following trans-oesophageal echocardiography. In the case reported here, a patient with cervical spondylosis on anti-coagulant therapy was referred to the Head and Neck Department because of a retro-pharyngeal haematoma with severe upper airway obstruction following transoesophageal echocardiography. Tracheotomy was required to guarantee respiratory function, while trans-cervical surgery was performed to evacuate the haematoma. Total recovery was achieved within 10 days. In conclusion, the head and neck surgeon should consider the need of surgical management in cases of retro-pharyngeal haematoma following trans-oesophageal echocardiography

Electro-optically tunable microring resonators in lithium niobate

Optical microresonators have recently attracted a growing attention in the photonics community. Their applications range from quantum electro-dynamics to sensors and filtering devices for optical telecommunication systems, where they are likely to become an essential building block. The integration of nonlinear and electro-optical properties in the resonators represents a very stimulating challenge, as it would incorporate new and more advanced functionality. Lithium niobate is an excellent candidate material, being an established choice for electro-optic and nonlinear optical applications. Here we report on the first realization of optical microring resonators in submicrometric thin films of lithium niobate. The high index contrast films are produced by an improved crystal ion slicing and bonding technique using benzocyclobutene. The rings have radius R=100 um and their transmission spectrum has been tuned using the electro-optic effect. These results open new perspectives for the use of lithium niobate in chip-scale integrated optical devices and nonlinear optical microcavities.Comment: 15 pages, 8 figure

In vitro activity of commercial probiotic Lactobacillus strains against uropathogenic Escherichia coli

Urinary tract infection (UTI) is one of the most prevalent infections in humans. In ≥80% of cases, the etiologic agents are strains of uropathogenic Escherichia coli (UPEC), which commonly reside in the gastrointestinal tract. Lactobacilli have been shown to prevent UTI reoccurrence by restoring the urogenital microbiota when administered vaginally or orally. The goal of this study was to determine if commercial probiotic Lactobacillus spp. reduce or clear UPEC in vitro. Results show that it is likely that lactobacilli may, in addition to restoring a healthy urogenital microbiota through acidification of their environment, also displace adhering UPEC and cause a reduction of infectio

Genome-based population structure analysis of the strawberry plant pathogen Xanthomonas fragariae reveals two distinct groups that evolved independently before its species description

Xanthomonas fragariae is a quarantine organism in Europe, causing angular leaf spots on strawberry plants. It is spreading worldwide in strawberry-producing regions due to import of plant material through trade and human activities. In order to resolve the population structure at the strain level, we have employed high-resolution molecular typing tools on a comprehensive strain collection representing global and temporal distribution of the pathogen. Clustered regularly interspaced short palindromic repeat regions (CRISPRs) and variable number of tandem repeats (VNTRs) were identified within the reference genome of X. fragariae LMG 25863 as a potential source of variation. Strains from our collection were whole-genome sequenced and used in order to identify variable spacers and repeats for discriminative purpose. CRISPR spacer analysis and multiple-locus VNTR analysis (MLVA) displayed a congruent population structure, in which two major groups and a total of four subgroups were revealed. The two main groups were genetically separated before the first X. fragariae isolate was described and are potentially responsible for the worldwide expansion of the bacterial disease. Three primer sets were designed for discriminating CRISPR-associated markers in order to streamline group determination of novel isolates. Overall, this study describes typing methods to discriminate strains and monitor the pathogen population structure, more especially in the view of a new outbreak of the pathogen

High-quality draft genome sequence of Pseudomonas reidholzensis strain CCOS 865T

We have sequenced and assembled the genome of Pseudomonas reidholzensis CCOS 865T, which was isolated in 2014 from forest soil. Members of the genus Pseudomonas play important roles in environmental systems and are utilized in many biotechnological processes. The genome of this species may provide an important resource for the discovery of novel enzyme activities

Genomics and current genetic understanding of Erwinia amylovora and the fire blight antagonist Pantoea vagans

Abstract The bacterial plant pathogen Erwinia amylovora causes fire blight, a major disease threat to pome fruit production worldwide with further impact on a wide-range of Rosaceae species. Important factors contributing to the development of the disease were discovered in the last decades. Comparative genomics of the genera Erwinia and Pantoea is coming into focus with the recent availability of complete genome sequences. Insights from comparative genomics now position us to answer fundamental questions regarding the evolution of E. amylovora as a successful pathogen and the critical elements for biocontrol activity of Pantoea spp. This trove of new data promises to reveal novel determinants and to understand interactive pathways for virulence, host range and ecological fitness. The ultimate aim is now to apply genomics and identify the pathogen Achilles heels and antagonist mechanisms of action as targets for designing innovative control strategies for fire blight

Perceived Hospital Preparedness Is Negatively Associated With Pandemic-Induced Psychological Vulnerability in Primary Care Employees: A Multicentre Cross-Sectional Observational Study.

The COVID-19 pandemic had a profound negative impact on the psychological wellbeing of healthcare providers (HPs), but little is known about the factors that positively predict mental health of primary care staff during these dire situations. We conducted an online questionnaire survey among 702 emergency department workers across 10 hospitals in Switzerland and Belgium following the first COVID-19 wave in 2020, to explore their psychological vulnerability, perceived concerns, self-reported impact and level of pandemic workplace preparedness. Participants included physicians, nurses, psychologists and nondirect care employees (administrative staff). We tested for predictors of psychological vulnerability through both an exploratory cross-correlation with rigorous correction for multiple comparisons and model-based path modelling. Findings showed that the self-reported impact of COVID-19 at work, concerns about contracting COVID-19 at work, and a lack of personal protective equipment were strong positive predictors of Depression, Anxiety, and Stress, and low Resilience. Instead, knowledge of the degree of preparedness of the hospital/department, especially in the presence of a predetermined contingency plan for an epidemic and training sessions about protective measures, showed the opposite effect, and were associated with lower psychological vulnerability. All effects were confirmed after accounting for confounding factors related to gender, age, geographical location and the role played by HPs in the hospital/department. Difficult working conditions during the pandemic had a major impact on the psychological wellbeing of emergency department HPs, but this effect might have been lessened if they had been informed about adequate measures for minimizing the risk of exposure

Molecular investigation of isolates from a multistate polymicrobial outbreak associated with contaminated total parenteral nutrition in Brazil

Background: Between November 2013 and June 2014, 56 cases of bacteremia (15 deaths) associated with the use of Total Parenteral Nutrition (TPN) and/or calcium gluconate (CG) were reported in four Brazilian states. Methods: We analyzed 73 bacterial isolates from four states: 45 from blood, 25 from TPN and three from CG, originally identified as Acinetobacter baumannii, Rhizobium radiobacter, Pantoea sp. or Enterobacteriaceae using molecular methods. Results: The first two bacterial species were confirmed while the third group of species could not be identified using standard identification protocols. These isolates were subsequently identified by Multi-Locus Sequence Analysis as Phytobacter diazotrophicus, a species related to strains from similar outbreaks in the United States in the 1970’s. Within each species, TPN and blood isolates proved to be clonal, whereas the R. radiobacter isolates retrieved from CG were found to be unrelated. Conclusion: This is the first report of a three-species outbreak caused by TPN contaminated with A. baumannii, R. radiobacter and P. diazotrophicus. The concomitant presence of clonal A. baumannii and P. diazotrophicus isolates in several TPN and blood samples, as well as the case of one patient, where all three different species were isolated simultaneously, suggest that the outbreak may be ascribed to a discrete contamination of TPN. In addition, this study highlights the clinical relevance of P. diazotrophicus, which has been involved in outbreaks in the past, but was often misidentified as P. agglomerans