Electron Localization and Mobility in Monolayer Fullerene Networks.

The novel 2D quasi-hexagonal phase of covalently bonded fullerene molecules (qHP C60), the so-called graphullerene, has displayed far superior electron mobilities, if compared to the parent van der Waals three-dimensional crystal (vdW C60). Herein, we present a comparative study of the electronic properties of vdW and qHP C60 using state-of-the-art electronic-structure calculations and a full quantum-mechanical treatment of electron transfer. We show that both materials entail polaronic localization of electrons with similar binding energies (≈0.1 eV) and, therefore, they share the same charge transport via polaron hopping. In fact, we quantitatively reproduce the sizable increment of the electron mobility measured for qHP C60 and identify its origin in the increased electronic coupling between C60 units.

Is a thin mechanism appropriate for aromatic nitration?

The mechanism of toluene nitration by NO2BF4 in dichloromethane solution is investigated by performing advanced ab initio MD simulations of the reaction trajectories, including at full quantum mechanical level the effects of both the solvent and of the counterion. The time evolution of the encounter complex, as well as that of the associated electronic structure, for different trajectories reveals that a single electron transfer step fastly occurs after reactants are accommodated in a common solvation shell, always preceding the formation of the σ-complex. The present results strongly suggest that the regioselectivity of the reaction is spin-density driven and that a thin mechanism, one based on reaction intermediates and transition states, can be appropriate to describe aromatic nitration.

Efficacy and tolerability of tapentadol for the treatment of chronic low back pain in elderly patients.

BACKGROUND: Chronic low back pain (CLBP) is a highly prevalent and disabling condition in the elderly, and yet it is undertreated and understudied in this patient population. Tapentadol is a central analgesic with an improved tolerability profile that may be particularly beneficial to the elderly CLBP. METHODS: We performed an observational retrospective study to comparatively assess the efficacy and tolerability of tapentadol in young and elderly patients with severe CLBP. Sixtyfive young patients (< 65 years) and 87 elderly patients (≥ 65 years) were titrated on tapentadol extended release to their optimal dose (25-250 mg bid) over 1 month and, then, maintained at that dose for 3 months. The primary endpoint were changes from baseline in 24-h pain intensity on a 0-10 Numerical Rating Scale (NRS) at month-4 of treatment (titration plus maintenance periods). Patients were assessed for several efficacy and tolerability outcomes using a battery of scales and tests for neuropathic pain intensity, quality of life and sleep, and cognitive and gastrointestinal functions. RESULTS: At pretreatment, young and elderly patients had similar pain intensities with younger patients presenting with more intense depressive and neuropathic pain symptoms, and lesser comorbidities and durations of pain (P < 0.05). Thirty-eight patients discontinued treatment because of adverse events occurring mostly during titration. Treatment with tapentadol was associated with comparable and clinically meaningful pain reductions in 24-h NRS from baseline to treatment month-4 both in young and elderly patients (- 5.3 ± 1.4 and - 4.8 ± 2.1; P < 0.01); a 50% pain relief was achieved in 66% and 58% of young and elderly patients. The percentage of patients with a neuropathic component decreased similarly in young and elderly patients (from 38 to 0% and from 19 to 3%; P < 0.01). Quality of life and sleep improved. The performances in global cognition and sustained attention tasks remained stable or improved across all age group. CONCLUSIONS: These findings indicate that tapentadol extended release maintains efficacy and good tolerability in CLBP patients with advancing age.

Water-Stable DMASnBr3 Lead-Free Perovskite for Effective Solar-Driven Photocatalysis.

Water-stable metal halide perovskites could foster tremendous progresses in several research fields where their superior optical properties can make differences. In this work we report clear evidence of water stability in a lead-free metal halide perovskite, namely DMASnBr3 , obtained by means of diffraction, optical and X-ray photoelectron spectroscopy. Such unprecedented water-stability has been applied to promote photocatalysis in aqueous medium, in particular by devising a novel composite material by coupling DMASnBr3 to g-C3 N4 , taking advantage from the combination of their optimal photophysical properties. The prepared composites provide an impressive hydrogen evolution rate >1700 µmol g-1 h-1 generated by the synergistic activity of the two composite costituents. DFT calculations provide insight into this enhancement deriving it from the favorable alignment of interfacial energy levels of DMASnBr3 and g-C3 N4 . The demonstration of an efficient photocatalytic activity for a composite based on lead-free metal halide perovskite in water paves the way to a new class of light-driven catalysts working in aqueous environments.

Reactivity and energy level of a localized hole in liquid water.

We study the reactivity and the energy level associated with the reduction of the H2O˙+ radical cation in liquid water by combining ab initio molecular dynamics simulations at the hybrid functional level, a grand-canonical formulation of solutes in aqueous solution, and nudge-elastic-band calculations. We demonstrate that this extremely oxidative solute promptly dissociates and calculate an energy barrier for the reaction of 0.06 eV, consistent with the short measured lifetimes. We calculate the energy level related to the H2O˙+/H2O redox couple with respect to the vacuum level and to the computational standard hydrogen electrode (SHE), using the thermodynamic integration method. This energy level is found to lie at 3.8 ± 0.1 eV above the SHE level, in remarkable agreement with a previous estimate based on thermodynamical data. The implications of the present results for the mechanism of water splitting at the heterogenous semiconductor-water interface are discussed.

Note: Assessment of the SCAN+rVV10 functional for the structure of liquid water.

The performance of the SCAN+rVV10 functional in modeling the structural properties of liquid water is studied through constant-volume ab initio molecular dynamics simulations with both classical and quantum nuclei. The radial distribution functions are found to be slightly overstructured with respect to experiment, but overall similar to those achieved with the bare SCAN and the rVV10 functionals. From the pressures calculated during the dynamics, it is inferred that the SCAN+rVV10 functional leads to a noticeable overestimation of the density of liquid water.

Ab initio Electronic Structure of Liquid Water.

Self-consistent GW calculations with efficient vertex corrections are employed to determine the electronic structure of liquid water. Nuclear quantum effects are taken into account through ab initio path-integral molecular dynamics simulations. We reveal a sizable band-gap renormalization of up to 0.7 eV due to hydrogen-bond quantum fluctuations. Our calculations lead to a band gap of 8.9 eV, in accord with the experimental estimate. We further resolve the ambiguities in the band-edge positions of liquid water. The valence-band maximum and the conduction-band minimum are found at -9.4 and -0.5 eV with respect to the vacuum level, respectively.

[Risk factors for burnout and job satisfaction in a sample of health professionals in Italy]. / Fattori di rischio del burnout e soddisfazione lavorativa. Un contributo di ricerca su un campione di operatori della sanità.

Health professionals are subject to a high risk of burnout syndrome due to specific stressful factors connected with their professional activity. This condition, which influences their quality of life, is characterized by physical and mental fatigue, a detached and apathetic attitude in social relations and feelings of frustration. The purpose of this study was to analyze, among a sample of 40 health professionals in a hospital in southern Italy, the relation between subjective feelings of satisfaction deriving from their professional activities and risk factors associated with burnout (age, sex, marital status, professional category, length of service in the health sector) . Participants were administered a questionnaire and tested by using the State-Trait Anxiety Inventory (STAI) X1 and X2, and the Minnesota Multiphasic Personality Inventory (MMPI) scales. Mean age of participating subjects was 41 years (range 27-59), 52% were male, and 65% were married. Nurses, midwives, social workers and technicians reported a greater degree of anxiety with respect to physicians and psychologists. Younger professionals (ages 30-38), males, unmarried subjects, and those with less years of work experience were found to be at greatest risk for burnout. Results are in agreement with those reported in the literature.

Redox levels in aqueous solution: Effect of van der Waals interactions and hybrid functionals.

We investigate redox levels in aqueous solution using a combination of ab initio molecular dynamics (MD) simulations and thermodynamic integration methods. The molecular dynamics are performed with both the semilocal Perdew-Burke-Ernzerhof functional and a nonlocal functional (rVV10) accounting for van der Waals (vdW) interactions. The band edges are determined through three different schemes, namely, from the energy of the highest occupied and of the lowest unoccupied Kohn-Sham states, from total-energy differences, and from a linear extrapolation of the density of states. It is shown that the latter does not depend on the system size while the former two are subject to significant finite-size effects. For the redox levels, we provide a formulation in analogy to the definition of charge transition levels for defects in crystalline materials. We consider the H(+)/H2 level defining the standard hydrogen electrode, the OH(-)/OH(∗) level corresponding to the oxidation of the hydroxyl ion, and the H2O/OH(∗) level for the dehydrogenation of water. In spite of the large structural modifications induced in liquid water, vdW interactions do not lead to any significant structural effect on the calculated band gap and band edges. The effect on the redox levels is also small since the solvation properties of ionic species are little affected by vdW interactions. Since the electronic properties are not significantly affected by the underlying structural properties, it is justified to perform hybrid functional calculations on the configurations of our MD simulations. The redox levels calculated as a function of the fraction α of Fock exchange are found to remain constant, reproducing a general behavior previously observed for charge transition levels of defects. Comparison with experimental values shows very good agreement. At variance, the band edges and the band gap evolve linearly with α. For α ≃ 0.40, we achieve a band gap, band-edge positions, and redox levels in overall good agreement with experiment.

Singlet fission in linear chains of molecules.

We develop a model configuration interaction Hamiltonian to study the electronic structure of a chain of molecules undergoing singlet fission. We first consider models for dimer and trimer and then we use a matrix partitioning technique to build models of arbitrary size able to describe the relevant electronic structure for singlet fission in linear aggregates. We find that the multi-excitonic state (ME) is stabilized at short inter-monomer distance and the extent of this stabilization depends upon the size of orbital coupling between neighboring monomers. We also find that the coupling between ME states located on different molecules is extremely small leading to bandwidths in the order of ∼10 meV. This observation suggests that multi-exciton states are extremely localized by electron-phonon coupling and that singlet fission involves the transition between a relatively delocalized Frenkel exciton and a strongly localized multi-exciton state. We adopt the methodology commonly used to study non-radiative transitions to describe the singlet fission dynamics in these aggregates and we discuss the limit of validity of the approach. The results indicate that the phenomenology of singlet fission in molecular crystals is different in many important ways from what is observed in isolated dimers.

Periodontal and Peri-Implant Diagnosis: Current Evidence and Future Directions.

Dentistry and periodontology in particular are constantly evolving in terms of both diagnostic and therapeutic tools [...].

End-Tidal Carbon Dioxide Measurement in Out-of-Hospital Cardiac Arrest as a Predictor of Return of Spontaneous Circulation: A Literature Review.

INTRODUCTION: One of the leading causes of morbidity and mortality worldwide is out-of-hospital cardiac arrest. Early defibrillation and high-quality cardiopulmonary resuscitation (CPR) have improved survival. The main goal of CPR is to achieve return of spontaneous circulation (ROSC), which is assessed by looking for a pulse, analyzing the heart rhythm, and assessing carbon dioxide levels. The use of cartography during CPR to confirm the correct position of the endotracheal tube during intubation or to assess the effectiveness of chest compressions has increased significantly in the last years. The aim of this review was to identify correlations between end-tidal carbon dioxide levels and the likelihood of ROSC in patients with out-of-hospital cardiac arrest. METHODS: A literature search was performed in MEDLINE (via Pubmed), Scopus, Web of Science, and Google Scholar databases from September to November 2022. Keywords combined with the Boolean operators (AND/OR) were used in both free text and Medical Subject Headings. Studies on adult patients published between 01/01/2016 and 28/09/2022 were searched, with no geographical restrictions. RESULTS: At the end of the selection process, 14 studies were included that investigated capnography in out-of-hospital CPR and reported at least 1 outcome between end-tidal carbon dioxide and ROSC or survival. DISCUSSION: Capnography is an advantageous tool due to its noninvasive characteristics, ease of use, and immediacy of data. In out-of-hospital cardiac arrest, the use of the end-tidal carbon dioxide appears to be an appropriate complementary tool to support clinical decisions, such as correct positioning of the endotracheal tube, optimizing ventilation in CPR, and as a predictor of ROSC.

Microbiota of Peri-Implant Healthy Tissues, Peri-Implant Mucositis, and Peri-Implantitis: A Comprehensive Review.

Understanding the microbiological profiles of peri-implant conditions is crucial for developing effective preventive and therapeutic strategies. This narrative review analyzes the microbial profiles associated with healthy peri-implant sites, peri-implant mucositis, and peri-implantitis, along with related microbiological sampling and analyses. Healthy peri-implant sites are predominantly colonized by Streptococcus, Rothia, Neisseria, and Corynebacterium species, in addition to Gram-positive cocci and facultatively anaerobic rods, forming a stable community that prevents pathogenic colonization and maintains microbial balance. In contrast, peri-implant mucositis shows increased microbial diversity, including both health-associated and pathogenic bacteria such as red and orange complex bacteria, contributing to early tissue inflammation. Peri-implantitis is characterized by even greater microbial diversity and a complex pathogenic biofilm. Predominant pathogens include Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, and unique species like Filifactor alocis and Fretibacterium fastidiosum. Additionally, less common species such as Staphylococcus and Enterobacteriaceae, contributing to disease progression through biofilm formation and increased inflammatory response, along with EBV and human cytomegalovirus with a still not defined role, and Candida albicans contribute to disease progression through biofilm formation, immune modulation, and synergistic inter-kingdom interactions. Future research should standardize diagnostic criteria, employ advanced molecular techniques, integrate microbial data with clinical factors, and highlight inter-kingdom interactions.

Oral Mycobiome and COVID-19.

The most common signs and symptoms of COVID-19 include fever, cough, dyspnea, conjunctivitis, diarrhea, and olfactory and gustatory disturbances [...].

Clinics and Practice: Consolidating Best Practices in Periodontal Management.

Periodontitis is a multifactorial inflammatory disease [...].

Charge Localization in Acene Crystals from Ab Initio Electronic Structure.

The performance of Koopmans-compliant hybrid functionals in reproducing the electronic structure of organic crystals is tested for a series of acene crystals. The calculated band gaps are found to be consistent with those achieved with the GW method at a fraction of the computational cost and in excellent accord with the experimental results at room temperature, when including the thermal renormalization. The energetics of excess holes and electrons reveals a struggle between polaronic localization and band-like delocalization. The consequences of these results on the transport properties of acene crystals are discussed.

Is Ozone a Valid Adjuvant Therapy for Periodontitis and Peri-Implantitis? A Systematic Review.

INTRODUCTION: Ozone is a naturally occurring unstable compound with three oxygen atoms that generally transforms into an oxygen molecule, releasing one oxygen atom. This feature has been exploited in dentistry for numerous applications, including for periodontal diseases and peri-implantitis. METHODS: This review was performed in relation to the PRISMA flow chart and was annotated in the PROSPERO register. PICO questions were used as research questions. The risk of bias in the non-randomized clinical trials was appraised using the ROBINS-I tool. RESULTS: An electronic search found a total of 1073 records, in particular, 842 from MEDLINE/PubMed, 13 from Bio Med Central, 160 from Scopus, 1 from the Cochrane library databases, and 57 from the PROSPERO register. A total of 17 studies were included in the present systematic review. Information regarding the characteristics of the periodontal clinical and radiographic parameters for gaseous ozone, ozonate water, ozonate oil, and ozone gel, including clinical attachment loss (CAL) probing depth (PPD), bleeding on probing (BoP), plaque index (PI), gingival index (GI), and marginal bone levels (MBL), were obtained. CONCLUSIONS: The studies included in this systematic review show different results regarding the ozone in periodontal treatment in association with or without SRP.

Nature of the Interaction of Alpha-D-Mannose and Escherichia coli Bacteria, and Implications for its Regulatory Classification. A Delphi Panel European Consensus Based on Chemistry and Legal Evidence.

The nature of alpha-D-mannose-natural aldohexose sugar, C-2 glucose epimer, whose intended use is for preventing urinary tract infections-in the interaction with E. coli is addressed in order to drive the issue of its regulatory classification as a medicinal product or medical device. PRISMA systematic review approach was applied; Delphi Panel method was used to target consensus on statements retrieved from evidence. Based on regulatory definitions and research evidence, the mechanism of D-mannose does not involve a metabolic or immunological action while there is uncertainty regarding the pharmacological action. Specific interaction between the product and the bacteria within the body occurs, but its nature is inert: it does not induce a direct response activating or inhibiting body processes. Moreover, the action of D-mannose takes place, even if inside the bladder, outside the epithelium on bacteria that have not yet invaded the urothelial tissue. Therefore, its mechanism of action is not directed to host structures but to structures (bacteria) external to the host's tissues. On the basis of current regulation, the uncertainty as regard a pharmacological action of alpha-D-mannose makes possible its medical device classification: new regulations and legal judgments can add further considerations. From a pharmacological perspective, research is driven versus synthetic mannosides: no further considerations are expected on alpha-D-mannose.

Cubic or Not Cubic? Combined Experimental and Computational Investigation of the Short-Range Order of Tin Halide Perovskites.

Tin-based metal halide perovskites with a composition of ASnX3 (where A= MA or FA and X = I or Br) have been investigated by means of X-ray total scattering techniques coupled to pair distribution function (PDF) analysis. These studies revealed that that none of the four perovskites has a cubic symmetry at the local scale and that a degree of increasing distortion is always present, in particular when the cation size is increased, i.e., from MA to FA, and the hardness of the anion is increased, i.e., from Br- to I-. Electronic structure calculations provided good agreement with experimental band gaps for the four perovskites when local dynamical distortions were included in the calculations. The averaged structure obtained from molecular dynamics simulations was consistent with experimental local structures determined via X-ray PDF, thus highlighting the robustness of computational modeling and strengthening the correlation between experimental and computational results.

Infection Control in Dental Practice during the COVID-19 Pandemic: What Is Changed?

The COVID-19 pandemic has profoundly changed our lives. Since the SARS-CoV-2 was discovered, many studies have been done on the transmission mode, its replication within humans, and its survival even in the outside environment and on inanimate surfaces. Undoubtedly, health care workers have faced the greatest risks because of their close contact with potentially infected patients. Of these, dental health care professionals are certainly among the most vulnerable categories, precisely because infection occurs with the airborne virus. The treatment of patients within the dental office has changed profoundly, respecting all preventive measures towards the patient and the practitioners themselves. The aim of this paper is to understand whether the protocols changed for the prevention of SARS-CoV-2 infection among dentists remained even after the most acute phase of the pandemic. In particular, this study analyzed habits, protocols, preventive measures, and any costs incurred in the COVID-19 era for the prevention of SARS-CoV-2 infection among dental workers and patients.