The significance of negativity of the target density in Frozen-Density Embedding Theory based simulations

The accuracy of any observable derived from multi-scale simulations based on Frozen- Density Embedding Theory (FDET) is affected by two inseparable factors: i) the nad approximation for the E xcT [ρ A , ρ B ] term in the FDET expression for the total energy and ii) the choice of the density ρ B (r) for which the FDET eigenvalue equation for the embedded wave-function is solved. If ρ B is locally larger than the exact density of the total system ρ AB , the difference ρ AB (r) − ρ B (r) (target density) cannot be obtained from FDET. For an arbitrary choice for ρ B , FDET provides only the upper bound of the exact energy. The relative significance of these two factors is investigated for four representative weakly bound intermolecular clusters and various choices for ρ B . It is shown that the violation of the non-negativity condition is the principal source of error in the FDET energy if ρ B is the density of the isolated environment, i.e., is generated without taking into account the interactions with the embedded species. Reduction of both the magnitude of the violation of the non-negativity condition and the error in the FDET energy can be pragmatically achieved by means of the explicit treatment of the electronic polarisation of the environment

Fusion of airborne MTIonSAR and ancillary information for vehicle tracking

The focus of this paper is on resolving some of the ambiguity inherent in locating moving targets in single-channel SAR images. Detection of moving targets relies on a technique named doublet detection, while tracking is based on velocity estimation in the range-Doppler plane; confirmation of the target as a mover is enabled by two specifically developed tests on the range-Doppler target path. Velocity estimation is performed through a theoretically derived formula. Comparison of the estimated target parameters with the road pattern as provided by a GIS containing the local road network is relied upon for target re-location. The method and the results of testing on real images are presented and discussed

Embedding non-rigid solutes in an averaged environment: a case study on rhodopsins

Many simulation methods concerning solvated molecules are based on the assumption that the solvated species and the solvent can be characterized by some representative structure of the solute and some embedding potential corresponding to this structure. This assumption is re-examined and generalized for conformationally flexible solutes. In the proposed and investigated generalization, the solute is characterized by a set of representative structures and the corresponding embedding potentials. The representative structures are identified by means of subdividing the statistical ensemble, which in this work is generated by a constant-temperature molecular dynamics simulation. The embedding potential defined in Frozen-Density Embedding Theory is used to characterize the average effect of the solvent in each subensemble. The numerical examples concern vertical excitation energies of protonated retinal Schiff bases in protein environments. It is comprehensively shown that subensemble averaging leads to huge computational savings compared to explicit averaging of the excitation energies in the whole ensemble while introducing only minor errors

Radiotherapy in patients with HIV: current issues and review of the literature

Although the introduction of highly active antiretroviral therapy has radically improved the life expectancy of patients with HIV, HIV positivity is still considered a major barrier to oncological treatment for patients with cancer because of their worse prognosis and increased susceptibility to toxic effects compared with patients who are immunocompetent. The use of radiotherapy with or without chemotherapy, immunotherapy, or molecular targeted therapy is the standard of care for several cancers. These new drugs and substantial improvements in radiotherapy techniques, including intensity-modulated radiotherapy, image-guided radiotherapy, and stereotactic ablative radiotherapy, are optimising the feasibility of such anticancer treatments and are providing new opportunities for patients with cancer and HIV. In this Review, we discuss the role of radiotherapy, with or without chemotherapy or new drugs, in the treatment of cancer in patients with HIV, with a focus on the efficacy and tolerability of this approach on the basis of available evidence. Moreover, we analyse and discuss the biological basis of interactions between HIV and radiotherapy, evidence from preclinical studies, and immunomodulation by radiotherapy in the HIV setting

Immunotherapy in association with stereotactic radiotherapy for Non-Small Cell Lung Cancer brain metastases: results from a multicentric retrospective study on behalf of AIRO

BACKGROUND: To define efficacy and toxicity of Immunotherapy (IT) with stereotactic radiotherapy (SRT) including radiosurgery (RS) or hypofractionated SRT (HFSRT) for brain metastases (BM) from non-small cell lung cancer (NSCLC) in a multicentric retrospective study from AIRO (Italian Association of Radiotherapy and Clinical Oncology). METHODS: NSCLC patients with BM receiving SRT + IT and treated in 19 Italian centers were analyzed and compared with a control group of patients treated with exclusive SRT. RESULTS: One hundred patients treated with SRT + IT and 50 patients treated with SRT-alone were included. Patients receiving SRT + IT had a longer intracranial Local Progression-Free Survival (iLPFS) (propensity score-adjusted P = .007). Among patients who, at the diagnosis of BM, received IT and had also extracranial progression (n = 24), IT administration after SRT was shown to be related to a better overall survival (OS) (P = .037). A multivariate analysis, non-adenocarcinoma histology, KPS = 70 and use of HFSRT were associated with a significantly worse survival (P = .019, P = .017 and P = .007 respectively). Time interval between SRT and IT ≤7 days (n = 90) was shown to be related to a longer OS if compared to SRT-IT interval >7 days (n = 10) (propensity score-adjusted P = .008). The combined treatment was well tolerated. No significant difference in terms of radionecrosis between SRT + IT patients and SRT-alone patients was observed. The time interval between SRT and IT had no impact on the toxicity rate. CONCLUSIONS: Combined SRT + IT was a safe approach, associated with a better iLPFS if compared to exclusive SRT

Frontiers in Multiscale Modeling of Photoreceptor Proteins

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