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A shape optimization problem for nematic and cholesteric liquid crystal drops
No full textWe generalize the shape optimization problem for the existence of stable equilibrium configurations of nematic and cholesteric liquid crystal drops surrounded by an isotropic solution to include a broader family of admissible domains with inner boundaries, allowing discontinuities in the director field across them. Within this setting, we prove the existence of optimal configurations under a volume constraint and show that the minimization problem is a natural generalization of that posed for regular domains
Evolution of Hydrogen-Bonding Networks in Glycerol Dimer and Trimer: How Close Are They to Water Clusters?
No full textGlycerol, a flexible triol, has found widespread use in biological and industrial applications due to its intricate intra- and intermolecular hydrogen (H)-bonding capability. Using a combination of experimental broadband rotational spectroscopy and high-level quantum chemistry calculations, we probed low-energy isomers of binary and ternary glycerol aggregates. Seven binary isomers and one ternary isomer were identified experimentally, with the aid of theoretical modeling. The experimental results offer critical benchmarks for theoretical geometry and relative energy ordering predictions across various levels of theory, especially for systems unusually rich in OH groups. Importantly, by detecting these isomers experimentally, we can trace the evolution of the 3D H-bonding networks up to the trimer, thereby gaining molecular-level insights into the initial stages of glycerol self-aggregation. The observed binary and ternary isomers reveal a delicate interplay of intra- and intermolecular H-bonds. The H-bonding networks of their respective most stable isomers show remarkable similarities to those of the observed isomers of (H2 O)6 and (H2 O)9 clusters. These findings shed new light on the origin of glycerol’s miscibility with water and its related biological functions
Delphi-Based Global Consensus on Fuchs Endothelial Corneal Dystrophy. An Endothelial Keratoplasty Learners Group Initiative
No full textPurpose: To identify areas of consensus among global experts for the management of Fuchs endothelial corneal dystrophy (FECD) in clinical practice, including its diagnosis, evaluation, decision-making principles with respect to intervention, and recommendations for performing cataract surgery in patients with FECD, including when to combine with keratoplasty. Design: Modified Delphi-based global consensus. Participants: Thirty-seven ophthalmologists from around the world with significant expertise in the management and mechanisms of FECD. Methods: A series of consensus statements about FECD were developed from three iterative rounds of structured questions and statements posed to the panel of experts. Two rounds were asynchronous electronic questionnaires, and the third round was a live virtual meeting. Experts responded anonymously to statements assessing consensus and to open-ended questions that invited diverse input. Main Outcome Measures: Consensus was defined as 70% agreement among experts. Results: Consensus was reached for 90 of 91 statements after three rounds. Experts agreed that FECD is defined by the presence of central or paracentral scattered or confluent guttae with or without edema. There was strong consensus that a chronic state of subclinical edema precedes the onset of clinically detectable edema that may or may not cause symptoms. With near-unanimous consensus, disease evaluation recommendations included assessing for findings that implicate the cornea as a source of decreased vision to separate it from the effect of comorbid conditions, as this would inform whether corneal intervention is appropriate. These findings include diurnal variation in vision, clinical or subclinical (tomographic) edema, and changes or differences in central corneal thickness. Based on current evidence, experts agreed that there are no effective medical therapies for FECD, and that Descemet membrane endothelial keratoplasty is the surgical treatment of choice when indicated. Conclusions: The consensus statements provide current globally endorsed recommendations for the diagnosis and management of FECD. The guidelines are important and relevant for general ophthalmologists, who typically first diagnose and evaluate FECD, and for cornea specialists, by allowing them to benchmark their current practice patterns against expert recommendations. This could help improve patient outcomes and establish a framework adaptable to future advances and evolving technologies in the management of FECD
Il Nulla e la Determinazione
No full textEsiste una struttura fondamentale del significato come tale, a cui ogni posizione teoretica può essere ricondotta? In caso affermativo, che posto hanno quei significati come ‘nulla’, ‘insignificanza’ ecc., che sono caratterizzati dal conflitto logico-semantico tra il contenuto che in essi è significato e il suo significare? Il Nulla è davvero impensabile e insignificabile come afferma la lunga tradizione filosofica?
Il Nulla e la Determinazione dà una risposta a queste e altre domande, introducendo la categoria dei significati incoerenti, riaffrontando la questione della pensabilità nulla e mostrando che esiste un nesso essenziale tra il modo in cui nella storia della filosofia si è posto o eluso il problema del nulla assoluto e quello in cui si è concepito il rapporto tra ente, divenire, eternità
Redefining Thyroid Nodule Evaluation: Demographics, Misleading Symptoms, and Diagnostic Challenges. Insights From a Multicenter Study
No full textObjective: Thyroid ultrasound (US) is the cornerstone for diagnosing nodular thyroid disease, yet many US examinations are prompted by nonspecific local symptoms (LS) like dysphagia or a palpable neck mass (NM). The clinical utility of such referrals remains debated. Methods: This multicenter retrospective study analyzed 614 patients diagnosed with thyroid nodules (TNs) via US from 2 endocrinology centers in Italy between December 2021 and October 2022. Patients were grouped based on referral reason: symptomatic TNs, further subdivided into NM and LS, versus nonsymptomatic TNs. Clinical, ultrasonographic, and management data were compared. Results: Symptomatic TNs accounted for 28.7% of cases (19.2% NM, 9.5% LS). NM patients were younger, more often female, and had larger, often cystic or isthmic-located nodules than nonsymptomatic TN patients. Conversely, LS patients had no significant differences in thyroid volume or nodule size but showed a higher prevalence of gastroesophageal reflux disease. Fine-needle aspiration was more common in the NM group because of larger nodules, but malignancy rates did not differ across groups. Surgical rates were similar, whereas thermal ablation was more frequent in the NM group. Conclusions: A third of TNs are diagnosed during US prompted by LS, yet only NMs are associated with distinct nodule characteristics. Dysphagia and dysphonia were nonspecific and more related to gastroesophageal reflux disease than TNs. These findings support caution against overuse of US. Demographics, nodule features, and location should guide clinical suspicion and imaging decisions to avoid unnecessary imaging and interventions
Nerve Conduction Abnormalities Beyond Conduction Block in Multifocal Motor Neuropathy. Impact on Diagnostic Criteria Accuracy
No full textBACKGROUND: Multifocal motor neuropathy (MMN) is a rare motor neuropathy diagnosed by identifying motor conduction block (CB), which may be absent or transient. This study aimed to evaluate nerve conduction abnormalities beyond CB and their diagnostic value. METHODS: A retrospective analysis included patients fulfilling the 2010 EFNS/PNS clinical criteria for MMN and controls with axonal polyneuropathy, lower motor neuron disease, or chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Electrophysiological studies evaluated motor distal latency prolongation, reduced motor conduction velocity, prolonged F-wave latency, absence of F-waves, abnormal temporal dispersion, and distal CMAP duration prolongation. The 2010 EFNS/PNS criteria for MMN were compared to an 'extended' set incorporating additional electrophysiological parameters. RESULTS: A total of 70 MMN patients and 359 controls were included. At least one nerve conduction abnormality, excluding motor CB, was detected in one or more nerve segments unaffected by CB in 71% of MMN patients, significantly more frequently than in axonal polyneuropathy or lower motor neuron disease patients. These parameters included abnormal temporal dispersion (47%), distal CMAP duration prolongation (31%), reduced motor conduction velocity (26%), absence of F-waves (9%), prolonged F-wave latency (6%), and motor distal latency prolongation (3%). Incorporating these parameters increased sensitivity for diagnosing probable/definite MMN by 26% (p < 0.001; compared to EFNS/PNS criteria), with minimal impact on specificity, even when compared to CIDP patients. CONCLUSION: Including additional electrophysiological parameters into the diagnostic criteria for MMN may enhance diagnostic sensitivity while maintaining comparable specificity. The observation of nerve conduction abnormalities beyond CB indicates a broader electrophysiological profile for MMN
Circular Economy Applied to Sludge Minimization: The STAR Project
Get PDFThe management of biological sludge from wastewater treatment plants (WWTPs) poses a significant environmental challenge due to increasing sludge production and the presence of emerging pollutants. This study investigates an innovative solution by integrating a thermophilic aerobic membrane reactor (TAMR) into the sludge treatment line of a medium-size WWTP, aiming to minimize biological sludge output while enhancing resource recovery. The study involved a six-month monitoring of an industrial-scale TAMR system, assessing the reduction in volatile solids (VSs) in thickened sludge and evaluating the compatibility of TAMR residues with conventional activated sludge (CAS) systems. The TAMR unit, which achieved up to a 90% reduction in VSs, was combined with traditional CAS processes, forming the STAR (Sludge Treatment and Advanced Recycling) configuration. This configuration reduced sludge output to just 10% of conventional levels while enabling the recirculation of nutrient-rich liquid effluents. Both batch and continuous respirometric tests demonstrated the biological treatability of TAMR residues, highlighting their potential reuse as external carbon sources and their positive impact on CAS system performance. The findings suggest that integrating mesophilic and thermophilic systems can significantly improve sludge management efficiency, lowering both operating costs and environmental impacts
