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BACKGROUND: Hip fracture is a major cause of hospitalization among the elderly population. The standard surgical treatment involves early repair to reduce mortality and morbidity. One type of treatment in the case of intertrochanteric and subtrochanteric fractures is intramedullary nailing, as it decreases soft tissue damage and permits early weight bearing. The most common anesthesia technique combines spinal anesthesia with a peripheral block. In cases where spinal anesthesia is contraindicated, general anesthesia is preferred. However, both techniques can lead to significant complications, especially in patients with multiple comorbidities. Pain management after hip surgery, particularly in elderly and frail individuals, poses a challenge. The pericapsular nerve group block (PENG) targets the innervation of the anterior portion of the hip joint and is increasingly used for pain management related to hip surgery. CASE SERIES: This paper presents a case series of three elderly patients who underwent pericapsular nerve group block (PENG) block combined with dexmedetomidine sedation for intramedullary femoral fixation. CONCLUSIONS: The PENG block can be effectively used as the sole anesthetic technique for managing elderly patients undergoing intramedullary femoral fixation while on antiplatelet drugs. This procedure effectively controlled pain during both the surgical and postoperative periods. The addition of dexmedetomidine for sedation enables comfortable and safe procedures, minimizing the risk of perioperative neurocognitive dysfunctions and without adverse effects on cardiorespiratory function. [ABSTRACT FROM AUTHOR]

A joint theoretical-experimental study on the optical properties of 5-N-succinimidyl-2.2 -bithiophene (NS-2T), a prototype system for a new class of biomarkers was conducted, and time-dependent density functional theory (TD-DFT) and approximate coupled-cluster single and doubles (CC2) calculations were performed in the ground and excited states. Results showed that CC2 and TD-DFT can very well describe the absorption and photoluminescence energies of the three systems, but the presence of several charge-transfer transitions in the TD-DFT spectrum of NS-2T required the use of a correlated method to validate the TD-DFT results.

Singlet and triplet excitation energies in oligothiophenes are analyzed using time-dependent density-functional theory (TD-DFT) with different exchange-correlation functionals. TD-DFT methods underestimate photoluminescence energies but the energy difference between singlet and triplet states shows a trends with the chain-length similar to coupled-cluster singles and doubles model (CC2).

We apply the frozen density embedding method, using a full relaxation of embedded densities through a freeze-and-thaw procedure, to study the electronic structure of several benchmark ground-state charge-transfer complexes, in order to assess the merits and limitations of the approach for this class of systems. The calculations are performed using both semilocal and hybrid exchange-correlation (XC) functionals. The results show that embedding calculations using semilocal XC functionals yield rather large deviations with respect to the corresponding supermolecular calculations. Due to a large error cancellation effect, however, they can often provide a relatively good description of the electronic structure of charge-transfer complexes, in contrast to supermolecular calculations performed at the same level of theory. On the contrary, when hybrid XC functionals are employed, both embedding and supermolecular calculations agree very well with each other and with the reference benchmark results. In conclusion, for the study of ground-state charge-transfer complexes via embedding calculations hybrid XC functionals are the method of choice due to their higher reliability and superior performance. [ABSTRACT FROM AUTHOR]

We compare the performance of different exchange-correlation functionals, based on the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation, for the structural and electronic properties of gold nanostructures. In particular we consider PBEsol (constructed to correctly describe solid-state systems) and PBEint [Phys. Rev. B 82, 113104 (2010)] which was recently introduced for hybrid interfaces and preserves the correct second-order gradient expansion of exchange energy (as in PBEsol) providing as well a significant nonlocality for higher density variation (as in PBE). We find that the PBEint functional gives a well balanced description of atomization energies, structural properties, energy differences between isomers, and bulk properties. Results indicate that PBEint is expected to be the most accurate functional for medium and large size gold clusters of different shapes. [ABSTRACT FROM AUTHOR]

Modifications of the optical properties of dimethyl-dithienothiophenes due to the oxygen functionalization of the central sulfur atom are investigated. We have measured the absorption, photoluminescence (PL) and PL excitation spectra, the PL quantum efficiencies, and the PL decay times. These experimental results are interpreted and compared with first-principles time-dependent density-functional theory calculations, which predict, for the considered systems, excitation and emission energies with an accuracy of 0.1 eV. It is found that the oxygenation strongly changes optical and photophysical properties. These effects are related to the modifications of the energetically lowest-unoccupied molecular orbital and the energetically second highest occupied one, which change the relative position of the two lowest singlet and triplet excited states. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The structural and optical properties of a heterostructure emitting in the midinfrared are analyzed. The results have suggested a type II band alignment with electrons localized in the conduction miniband of the InAs/GaSb superlattice matrix and holes localized in the monolayerlike InSb.

The intramolecular radiative and nonradiative relaxation processes of three thiophene-S,S-dioxide derivatives with different molecular rigidity are investigated in different solutions and inert matrix. It is shown that the fluorescence quantum efficiency and the relaxation dynamics are strongly dependent on the environment viscosity, whereas they are almost independent of the environment polarity.

We study the physisorption of organic oligomers on the strongly ionic ZnO(101̄0) surface by using first-principles density-functional theory and nonempirical embedding methods. It turns out that the in-plane variation of the molecule-substrate interaction energy and the bonding dipole in the vertical direction are linked up by a linear relationship originating from the electrostatic coupling of the molecule with the periodic dipolar electric field generated by the Zn-O surface dimers. Long oligomers with a highly axial π-electron system such as sexiphenyl become well oriented with alignment energies of several 100 meV along rows of a positive electric field, in full agreement with recent experiments. These findings define a new route towards the realization of highly ordered self-assembled arrays of oligomers or polymers on ZnO(101̄0) and similar surfaces. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) has rich physical properties with potential implications for both fundamental physics and new applications. To date, the main focus of applied research is to tune its optical properties, which is usually done via doping and/or nanoengineering. However, understanding the role of d electrons in materials and possible functionalization of d-electron properties are still major challenges. Herewith, within a combination of an innovative experimental technique, high-energy optical conductivity, and state-of-the-art ab initio electronic structure calculations, we report an emerging, novel resonant exciton in the deep ultraviolet region of the optical response. The resonant exciton evolves upon low-concentration Ta substitution in anatase TiO2 films. It is surprisingly robust and related to strong electron-electron and electron-hole interactions. The d- and f-orbital localization, due to Ta substitution, plays an unexpected role, activating strong electronic correlations and dominating the optical response under photoexcitation. Our results shed light on a new optical phenomenon in anatase TiO2 films and on the possibility of tuning electronic properties by Ta substitution. [ABSTRACT FROM AUTHOR]