693 research outputs found
VISITOR
SISTESI DI RECETTORI A BASE UREIDICA PER IL RICONOSCIMENTO DI ANIONI CARBOSSILATOS
Cochlear implant in a subject affected by the Chudley-McCullough Syndrome
Objectives: The Chudley-McCullough Syndrome (CMS) is a rare autosomal-recessively inherited disorder caused by mutations in the GPSM2 gene, characterised by deafness and brain anomalies. The purpose of this paper is to report about a case of cochlear implant (CI) procedure in a subject affected by CMS. Methods: A 31-year-old subject affected by CMS referred to our centre requiring an evaluation for a CI, as the results with her hearing aids, which she had been using since she was 2-years-old, were unsatisfactory. A profound bilateral sensorineural hearing loss was pointed out. Pure tone audiometry in free field with hearing aids and speech perception results were poor. The subject was counselled about the surgical procedure and the surgery was performed with no complications. Results: The cochlear implant was switched on 22 days after surgery and the subject began speech therapy training. After 1 year, hearing and speech perception results were satisfactory. The hearing threshold in free field with the CI was around 30 dB, and the open set speech perception score reached 55% in silence. Conclusions: The reported case demonstrates that CI is a feasible and safe procedure in subjects with CMS. Furthermore, since satisfactory hearing and speech perception results were achieved we recognise that cochlear implant should be considered the best option for hearing restoration in subjects with CMS and profound sensorineural hearing loss
Record Rate Enhancements for Tetrathiafulvalene Guests in the Formation of Bipyridinium- and Diazapyrenium-Based [2]Pseudorotaxanes
The catalytic effects
of guests <b>5</b>–<b>7</b> on the cyclization
of <b>1</b> and <b>3</b> have been
measured at 62 °C in MeCN. A record rate acceleration of more
than 2000 times has been observed in the cyclization of the tricationic
host <b>3</b> featuring large diazapyrenium π-surfaces
by tetrathiafulvalene guests <b>6</b> and <b>7</b>. The
results emphasize the role played by extended π-surfaces in
the host and the goodness of a tetrathiafulvalene core in the guest,
enhanced by polyethereal side arms
Ion-Pair Recognition by Metal-Salophen and Metal-Salen Complexes
The development of heteroditopic receptor systems that can simultaneously bind cationic and anionic species is one of the most challenging research topics in supramolecular chemistry, attracting the attention of a large number of research groups worldwide. Such an interest is due especially to the fact that the overall receptor-ion-pair complex is neutral and this can be advantageous in many situations, such as salt solubilization and extraction, and membrane-transport applications. Receptors designed for ion-pair complexation are molecules comprisingwell-known anion-binding motifs and familiar cation-binding sites. An important family of compounds that can use metal Lewis-acidic centres for anion recognition and that can be easily derivatized to introduce an additional binding site for the cation is metal-salophen and metal-salen complexes. This short review shows that the high versatility of salen and salophen ligands and of the corresponding metal complexes allows, through simple modifications of the basic skeleton, the obtention of highly efficient receptors for ion pairs
Micro-habitat shifts by butterflies foster conservation strategies to preserve pollinator diversity in a warming Mediterranean climate
The Butterfly Monitoring Scheme based on linear transects conducted by citizen scientists has become a fundamental indicator for understanding the impact of climate change on butterfly populations. A key finding is the fast poleward expansion of butterfly distributions in Europe, coupled with slower population declines in southern regions. Given that the Mediterranean region is a climate change hotspot, understanding the largely unknown mechanisms employed by butterflies to cope with increasing aridity is crucial for developing data-driven conservation strategies. To address this issue, we developed a monitoring approach based on 90 transects fully covering areas of 50 m × 50 m squares instead of linear paths. This enabled us to explore the fine-scale dynamics of 80 butterfly species and their association with vegetational units in the Mediterranean hills (∼800 m a.s.l. as maximum altitude) of the MAB UNESCO Reserve of Monte Peglia (Central Italy). We sampled the transects from April to October 2022 (the locally hottest summer of the last decade) and documented three main patterns: 1) butterfly richness and abundance correlate with environmental features and these relationships vary across seasons. Richer sites consisted of some 30 % of woodland and were those closer to water, mostly during summer (area-based analysis). 2) Environmental preferences vary with species traits. Specialist species and those adapted to colder climates and narrower temperature ranges were more abundant in higher altitudes sites, closer to water and with wider woodland coverage (fourth-quadrant analysis). 3) Although most species preferred meadows, when temperature increases, they increased their abundance in sites with wider tree coverage, closer to streams, and at higher altitude (species-based analysis). These dynamics demonstrate that butterflies opportunistically move to cooler micro-habitats to buffer elevated temperatures. This phenomenon potentially involves most of the community since the species showing significant effects encompass >80 % of the observed individuals. Our analysis introduces new dimensions to the niche of Mediterranean butterflies, highlighting the significance of shady micro-habitats, altitudinal ranges, and water streams. These factors are likely to become increasingly critical with rising aridity levels. By combining our findings with existing literature data, we have provided a protocol aimed at preserving Mediterranean butterflies within the resist-accept-direct framework
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