2,111 research outputs found
Genetic and biochemical analyses of chromosome and plasmid gene homologues encoding ICL and ArCP domains in Vibrioanguillarum strain 775
Anguibactin, the siderophore produced by Vibrio anguillarum 775 is synthesized from 2,3-dihydroxybenzoic acid (DHBA), cysteine and hydroxyhistamine via a nonribosomal peptide synthetase (NRPS) mechanism. Most of the genes encoding anguibactin biosynthetic proteins are harbored by the pJM1 plasmid. In this work we report the identification of a homologue of the plasmid-encoded angB on the chromosome of strain 775. The product of both genes harbor an isochorismate lyase (ICL) domain that converts isochorismic acid to 2,3-dihydro-2,3-dihydroxybenzoic acid, one of the steps of DHBA synthesis. We show in this work that both ICL domains are functional in the production of DHBA in V. anguillarum as well as in E. coli. Substitution by alanine of the aspartic acid residue in the active site of both ICL domains completely abolishes their isochorismate lyase activity in vivo. The two proteins also carry an aryl carrier protein (ArCP) domain. In contrast with the ICL domains only the plasmid encoded ArCP can participate in anguibactin production as determined by complementation analyses and site-directed mutagenesis in the active site of the plasmid encoded protein, S248A. The site-directed mutants, D37A in the ICL domain and S248A in the ArCP domain of the plasmid encoded AngB were also tested in vitro and clearly show the importance of each residue for the domain function and that each domain operates independently.
Quantum enhanced positioning and clock synchronization
A wide variety of positioning and ranging procedures are based on repeatedly
sending electromagnetic pulses through space and measuring their time of
arrival. This paper shows that quantum entanglement and squeezing can be
employed to overcome the classical power/bandwidth limits on these procedures,
enhancing their accuracy. Frequency entangled pulses could be used to construct
quantum positioning systems (QPS), to perform clock synchronization, or to do
ranging (quantum radar): all of these techniques exhibit a similar enhancement
compared with analogous protocols that use classical light. Quantum
entanglement and squeezing have been exploited in the context of
interferometry, frequency measurements, lithography, and algorithms. Here, the
problem of positioning a party (say Alice) with respect to a fixed array of
reference points will be analyzed.Comment: 4 pages, 2 figures. Accepted for publication by Natur
INQUADRAMENTO CLINICO E MANAGEMENT DELLO SCHWANNOMA ESCLUSIVAMENTE INTRALABIRINTICO
Lo schwannoma intralabirintico (SIL) è un raro tumore benigno (prevalenza 0.1-0.4%) che origina dalle cellule di Schwann situate a ridosso della giunzione cito-neurale dellâVIII n.c. I sintomi clinici includono ipoacusia neurosensoriale monolaterale progressiva (95%), acufeni (51%), disequilibrio (35%), vertigine (22%), fullness (2%). Alla risonanza magnetica (RM) il tumore si presenta come una massa circoscritta, iperintensa in T1, ipointensa in T2 e con enhancement dopo gadolinio nelle immagini T1-pesate. Il management prevede in prima istanza osservazioni seriali con RM âwait and scan approachâ. La chirurgia, considerando le complicanze descritte quali anacusia (100%), paralisi VII n.c. (4%), fistola liquorale (5.4%), meningite (1.8%), è riservata a casi limitati e dipende da: etĂ , condizioni generali del paziente, sede e dimensioni del tumore ed è consigliabile in caso di un pattern di crescita invasivo e presenza di sintomi vertiginosi non responsivi al trattamento medico
Rapid Lung Ultrasound COVID-19 Severity Scoring with Resource-Efficient Deep Feature Extraction
Artificial intelligence-based analysis of lung ultrasound imaging has been
demonstrated as an effective technique for rapid diagnostic decision support
throughout the COVID-19 pandemic. However, such techniques can require days- or
weeks-long training processes and hyper-parameter tuning to develop intelligent
deep learning image analysis models. This work focuses on leveraging
'off-the-shelf' pre-trained models as deep feature extractors for scoring
disease severity with minimal training time. We propose using pre-trained
initializations of existing methods ahead of simple and compact neural networks
to reduce reliance on computational capacity. This reduction of computational
capacity is of critical importance in time-limited or resource-constrained
circumstances, such as the early stages of a pandemic. On a dataset of 49
patients, comprising over 20,000 images, we demonstrate that the use of
existing methods as feature extractors results in the effective classification
of COVID-19-related pneumonia severity while requiring only minutes of training
time. Our methods can achieve an accuracy of over 0.93 on a 4-level severity
score scale and provides comparable per-patient region and global scores
compared to expert annotated ground truths. These results demonstrate the
capability for rapid deployment and use of such minimally-adapted methods for
progress monitoring, patient stratification and management in clinical practice
for COVID-19 patients, and potentially in other respiratory diseases.Comment: Accepted to ASMUS 2022 Workshop at MICCA
Allergic rhinitis
Allergic rhinitis is a common disorder that is strongly linked to asthma and conjunctivitis. It is usually a long-standing condition that often goes undetected in the primary-care setting. The classic symptoms of the disorder are nasal congestion, nasal itch, rhinorrhea and sneezing. A thorough history, physical examination and allergen skin testing are important for establishing the diagnosis of allergic rhinitis. Second-generation oral antihistamines and intranasal corticosteroids are the mainstay of treatment. Allergen immunotherapy is an effective immune-modulating treatment that should be recommended if pharmacologic therapy for allergic rhinitis is not effective or is not tolerated. This article provides an overview of the pathophysiology, diagnosis, and appropriate management of this disorder
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