Ecology and biology of the Antarctic giant fish Dissostichus mawsoni (Pisces, Nototheniidae): reproduction, trophic role and migrations in the Ross Sea region

Three different studies have been implemented to fill gaps in the knowledge of the Antarctic toothfish (Dissostichus mawsoni) life cycle in the Ross Sea. First, presence, abundance and size distribution of toothfish in the shelf, in areas periodically covered by sea ice, were investigated by means of Baited Remote Underwater Video systems (BRUVs), an emerging technology never employed before in such kind of habitat. The study was developed from 2015 to 2018 in McMurdo Sound and Terra Nova Bay, it highlighted the efficacy of the methodology for investigating the species, recording dozens of fish of different sizes. We started to make some inferences on how environmental variables influence the distribution of the toothfish in shelf areas, but even more important, we established a working protocol useful for future works. The second section has been focused on the Second Winter Survey conducted in September-October 2019 onboard of a New Zealand fishing vessel with the aim to investigate toothfish reproductive biology, its spawning period and the eggs development and dispersion. The results obtained, combined with those from the First Winter Survey conducted in June-July 2016, allowed to have for the first time a picture of Antarctic toothfish reproduction: the spawning occurs in a wide area in correspondence of the Pacific Antarctic Ridge, it happens in the middle of the winter, and eggs set during all their development in the surface layer of the water column. The last part of the work put light on the fate of toothfish after spawning, a question arose from the observation of the high percentage of sensibly debilitated individuals (named \u201caxe handle\u201d) in the breeding ground. Samples of muscles from six individuals (two \u201caxe handle\u201d and two regular from the breeding area, and two regular from the shelf) were investigated with regard to lipid distribution and composition. The analysis led us to reason on lipid mobilization and usage as energy reserve and/or for neutral buoyancy for reproductive migration, how consistent is their depletion and if toothfish actively feed in the northern area. Different hypotheses on what could cause the frequent poor condition after-spawning and its potential consequences have been illustrated, with the aim to give cues for future insights

Top-philic ALP phenomenology at the LHC: the elusive mass-window

We study the LHC phenomenology of an Axion Like Particle (ALP) that couples only derivatively with the top quark at tree level. We inspect the radiatively induced couplings with the SM fermions and (gauge) bosons and the associated production and decay mechanisms of the ALP. We focus on the most challenging mass window that remains open for a top-philic ALP, i.e., the range between tens and hundreds of GeV. Not only ALP production processes but also virtual ALP contributions to final states with top quarks are considered in detail. We show how searches through resonant production, such as ALP production in association with a $t\bar t$ pair, are complementary to precision measurements of $t \bar t$ and $t\bar t t \bar t$ final states, the latter being competitive or even more powerful for a top-philic ALP in this mass window. Finally, we explore the scenario where the top-philic ALP acts as a mediator to a dark-matter sector, resulting in missing energy signatures at the LHC. We find that the LHC constraints from $t \bar t$, $t\bar t t \bar t$ and ALP + jet production, together with those from $t \bar t$ + ALP production, can already exclude a large fraction of the parameter space leading to the correct relic abundance.Comment: 45 pages + appendices, 23 figure

Organic free radicals as circularly polarized luminescence

Chiroptical properties of two chiral atropisomers of propeller‐like trityl‐based radical derivatives have been analyzed. A new absolute configuration (AC) assignment has been made, according to the combination of experimental and theoretical data. In this sense, their ACs have been determined through the comparison of the Cotton effects recorded by electronic circular dichroism (ECD) with the theoretical ECD of the open shell structures obtained by TD‐DFT calculations. Finally, their circularly polarized luminescence (CPL) responses have been addressed. Remarkably, this is the first description of organic free radicals as intrinsic CPL emitters. Opposite signed CPL has been detected for each pair of conformers, with acceptable luminescent dissymmetry factors (|glum|≈0.5–0.8×10−3) considering their pure organic nature. In fact, highly efficient chiral emissions have been demonstrated, according to the comparison of |glum| with their respective absorption anisotropy factors (|gabs|). This pioneering study lays the foundations for the optimization of new magnetically active organic chiral emitters.The authors are grateful for the financial support received from: MOTHER (MAT2016-80826-R) granted by the DGI (Spain), GenCat (2017-SGR-918) financed by DGR (Catalunya) and the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015-0496) and through the “Proyecto interdisciplinar de frontera“, FIP-2018 HECTIC-PTM. We acknowledge the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC-2015-STG-677023). This study has been also supported by the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. P. M. B. gratefully acknowledges financial support from the Juan de la Cierva-Formación 2015 programme (FJCI-2015-23577) supported by MINECO. A. G. C. also thanks RyC-2013-12943 contract from MINECO. We also acknowledge Prof. O. Trapp for kindly suppling the DCxplorer software

A new record and biological evidence supporting the establishment of Beryx splendens (Actinopterygii: Beryciformes: berycidae) in the western Mediterranean basin

A new specimen of splendid alfonsino, Beryx splendens Lowe, 1834, was caught by trawling in July 2016 in the Ligurian Sea at the depth of 350 m, in the proximity of a submarine canyon. It represents the 10th documented record of B. splendens in the Mediterranean. Because of the rarity of the records in the basin, there could be doubts whether to consider or not such species as established in the area. However, some fndings may support the hypothesis of the possible establishment of the species in the Mediterranean Sea. For example, the stomach of the specimen was nearly full, with rests of one crustacean decapod, one fsh, and some cephalopods, which are commonly reported prey items for the species. Macroscopic observation and histological analysis of the gonads revealed that the specimen was a male in an advanced stage of gonadal development. Finally, the coherence of habitat type and prey items with that of extra-Mediterranean populations coupled with gonadal maturation consistent with the observations on other specimens caught in the Mediterranean

Referral Patterns in Oral Medicine: A Retrospective Analysis of an Oral Medicine University Center in Southern Italy

Referral of a patient from one healthcare provider to another is an important part of the medical practice. The aim of this study was to analyze the referral process to the Oral Medicine Unit in a university-based tertiary center in Southern Italy. A chart review of new referrals to the Oral Medicine Unit during a 24-month period was conducted. The following data were recorded: demographic characteristics, medical history, number of physicians seen prior to Oral Medicine assessment, referral source, diagnostic procedures ordered by referrals, reason for referral, site of lesion/condition, final diagnosis. Then, the rates of correct identification for health-care professionals and the appropriateness of the reference diagnosis based on the disease were calculated with descriptive statistic indicators. There were 583 new first consultations. A total of 62.9% of patients were referred by general dental practitioners, 27.4% by physicians, and 9.7% did not have a referral. The most common diseases for referral were immune-mediated diseases (39.6%) and oro-facial pain disorders (25.2%). Only 28.5% of patients had a correct provisional diagnosis. The results of this study show the need to implement curricula in the field of oral medicine among dentistry and medical students, and to support the continuing education among healthcare providers to reduce diagnostic delay for oral diseases

An Enantiopure Propeller‐Like Trityl‐Brominated Radical: Bringing Together a High Racemization Barrier and an Efficient Circularly Polarized Luminescent Magnetic Emitter

A new persistent organic free radical has been synthetized with Br atoms occupying the ortho‐ and para‐positions of a trityl core. After the isolation of its two propeller‐like atropisomers, Plus (P) and minus (M), their absolute configurations were assigned by a combination of theoretical and experimental data. Remarkably, no hints of racemization were observed up to 60 °C for more than two hours, due to the higher steric hindrance imposed by the bulky Br atoms. Therefore, when compared to its chlorinated homologue (t1/2=18 s at 60 °C), an outstanding stability against racemization was achieved. A circularly polarized luminescence (CPL) response of both enantiomers was detected. This free radical shows a satisfactory luminescent dissymmetry factor (|glum(592 nm)|≈0.7×10−3) despite its pure organic nature and low luminescence quantum yield (LQY). Improved organic magnetic CPL emitters derived from the reported structure can be envisaged thanks to the wide possibilities that Br atoms at para‐positions offer for further functionalization.The authors are grateful for the financial support received from: MOTHER project (MAT2016-80826-R) granted by the DGI (Spain), GenCat (2017-SGR-918) financed by DGR (Catalunya) and the Spanish Ministry of Economy and Competitiveness (PGC2018-095808-B-I00 and PGC2018-101181-B-I00 projects) and through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015-0496) and through the “Proyecto Interdisciplinar de Frontera“, FIP-2018 HECTIC-PTM. We acknowledge the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC-2015-STG-677023). This study has been also supported by the Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. P. M. B. gratefully acknowledges financial support from the Juan de la Cierva-Formación 2015 programme (FJCI-2015-23577) supported by MINECO and, together with J.V, A. G. C. also thanks RyC-2013-12943 contract from MINECO. We also thankthe Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, for allocating instrument time to this project

Electrochemical and X-ray Photoelectron Spectroscopy Surface Characterization of Interchain-Driven Self-Assembled Monolayer (SAM) Reorganization

Herein, we report a combined strategy encompassing electrochemical and X-ray photoelectron spectroscopy (XPS) experiments to investigate self-assembled monolayer (SAM) conformational reorganization onto an electrode surface due to the application of an electrical field. In particular, 3-mercaptopriopionic acid SAM (3MPA SAM) modified gold electrodes are activated with a 1-ethyl-3- (3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysulfosuccinimide (NHSS) (EDC-NHSS) mixture by shortening the activation time, from 2 h to 15/20 min, labelled as Protocol-A, -B and -C, respectively. This step, later followed by a deactivation process with ethanolamine (EA), plays a key role in the reaction yields (formation of N-(2-hydroxyethyl)-3-mercaptopropanamide, NMPA) but also in the conformational rearrangement observed during the application of the electrical field. This study aims at explaining the high performance (i.e., single-molecule detection at a large electrode interface) of bioelectronic devices, where the 3MPA-based SAM structure is pivotal in achieving extremely high sensing performance levels due to its interchain interaction. Cyclic voltammetry (CV) experiments performed in K4Fe(CN)6:K3Fe(CN)6 for 3MPA SAMs that are activated/deactivated show similar trends of anodic peak current (IA) over time, mainly related to the presence of interchain hydrogen bonds, driving the conformational rearrangements (tightening of SAMs structure) while applying an electrical field. In addition, XPS analysis allows correlation of the deactivation yield with electrochemical data (conformational rearrangements), identifying the best protocol in terms of high reaction yield, mainly related to the shorter reaction time, and not triggering any side reactions. Finally, Protocol-C’s SAM surface coverage, determined by CV in H2SO4 and differential pulse voltammetry (DPV) in NaOH, was 1.29 * 1013 molecules cm2, being similar to the bioreceptor surface coverage in single-molecule detection at a large electrode interface

Surface composition of mixed self-assembled monolayers on Au by infrared attenuated total reflection spectroscopy

Abstract Self-assembled monolayers (SAMs) of N-(2-hydroxyethyl)-3-mercaptopropanamide (NMPA) were synthesized directly on the surface of electron-beam evaporated Au films, starting from 3-mercaptopropionic acid (3MPA) via ethyl-3-(3-dimethylamino-propyl)carbodiimide/N-hydroxysulfosuccinimide sodium salt (EDC/NHSS) coupling with ethanolamine hydrochloride. The influence on the reaction yield of the acidity of EDC/NHSS solutions (pH = 5.6 or 4.8) was assessed by exploiting the high surface sensitivity of infrared attenuated total reflection spectroscopy. The light-matter interaction was modeled in the framework of a matrix formalism considering the complete multi-layer sample structure. A comparison between the relative intensity of the main absorption bands, associated with amide I and carbonyl stretching of carboxylic acid or amide II vibrations, with a calibration curve obtained from the measurement of mixed 3MPA/NMPA SAMs, show that the more acid solution is 16% more efficient. This is mostly due to the higher protonation of the 3MPA

The Arrangement of the Peripheral Olfactory System of Pleuragramma antarcticum: A Well-Exploited Small Sensor, an Aided Water Flow, and a Prominent Effort in Primary Signal Elaboration

The olfactory system is constituted in a consistent way across vertebrates. Nasal structures allow water/air to enter an olfactory cavity, conveying the odorants to a sensory surface. There, the olfactory neurons form, with their axons, a sensory nerve projecting to the telencephalic zone\u2014named the olfactory bulb. This organization comes with many different arrangements, whose meaning is still a matter of debate. A morphological description of the olfactory system of many teleost species is present in the literature; nevertheless, morphological investigations rarely provide a quantitative approach that would help to provide a deeper understanding of the structures where sensory and elaborating events happen. In this study, the peripheral olfactory system of the Antarctic silverfish, which is a keystone species in coastal Antarctica ecosystems, has also been described, employing some quantitative methods. The olfactory chamber of this species is connected to accessory nasal sacs, which probably aid water movements in the chamber; thus, the head of the Antarctic silverfish is specialized to assure that the olfactory organ keeps in contact with a large volume of water\u2014even when the fish is not actively swimming. Each olfactory organ, shaped like an asymmetric rosette, has, in adult fish, a sensory surface area of about 25 mm2, while each olfactory bulb contains about 100,000 neurons. The sensory surface area and the number of neurons in the primary olfactory brain region show that this fish invests energy in the detection and elaboration of olfactory signals and allow comparisons among different species. The mouse, for example\u2014which is considered a macrosmatic vertebrate\u2014has a sensory surface area of the same order of magnitude as that of the Antarctic silverfish, but ten times more neurons in the olfactory bulb. Catsharks, on the other hand, have a sensory surface area that is two orders of magnitude higher than that of the Antarctic silverfish, while the number of neurons has the same order of magnitude. The Antarctic silverfish is therefore likely to rely considerably on olfaction