144 research outputs found
Electronic and magnetic properties of the interface between metal-quinoline molecules and cobalt
A rapid spectroscopic method to detect the fraudulent treatment of tuna fish with carbon monoxide
Carbon monoxide (CO) can be used to treat fresh meat and fish in order to retain its 'fresh' red colour appearance for a longer period of time. In fact, upon aging, myoglobin is oxidized to met-myoglobin with the concomitant blue-shift and broadening of the Soret maximum, which brings about a change in the colour of the fish, revealing that it is no longer fresh. The use of carbon monoxide, which reacts with the oxy-myoglobin to form a fairly stable cherry red carboxy-myoglobin complex may mask spoilage, because the CO-complex can be stable beyond the microbiological shelf life of the meat. The presence of CO in tuna fish has been investigated by optical spectroscopy as the formation of the CO adduct can be easily detected by the combined analysis of electronic absorption spectra in their normal and second derivative modes, monitoring the intense Soret band at 420 nm. The presence of met- and oxy-myoglobin can obscure the presence of small amounts of the CO adduct; however, it can be revealed by chemically reducing the met- and oxy-forms to the deoxy-form in an anaerobic environment. This spectroscopic method provides a qualitatively rapid laboratory screening procedure for food control to unmask the presence of CO in frozen or fresh fish. (c) 2006 Elsevier Ltd. All rights reserved
Transmission through correlated CuCoCu heterostructures
The effects of local electronic interactions and finite temperatures upon the
transmission across the CuCoCu metallic heterostructure are studied in
a combined density functional and dynamical mean field theory. It is shown
that, as the electronic correlations are taken into account via a local but
dynamic self-energy, the total transmission at the Fermi level gets reduced
(predominantly in the minority spin channel), whereby the spin polarization of
the transmission increases. The latter is due to a more significant
-electrons contribution, as compared to the non-correlated case in which the
transport is dominated by and electrons.Comment: 29 pages, 7 figures, submited to PR
Role of lysines in cytochrome c – cardiolipin interaction
Cytochrome c undergoes structural variations during the apoptotic process; such changes have been related with modifications occurring in the protein when it forms a complex with cardiolipin, one of the phospholipids constituting the mitochondrial membrane. Although several studies have been performed to identify the site(s) of the protein involved in the cytochrome c/cardiolipin interaction, to date the location of this hosting region(s) remains unidentified and is a matter of debate. To gain a deeper insight into the reaction mechanism, we investigate the role that the Lys72, Lys73 and Lys79 residues play in the cytochrome c/cardiolipin interaction, as these side chains appear to be critical for cytochrome c/cardiolipin recognition. The Lys72Asn, Lys73Asn, Lys79Asn, Lys72/73Asn and Lys72/73/79Asn mutants of horse heart cytochrome c were produced and characterized by circular dichroism, UV-visible and resonance Raman spectroscopies, and the effects of the mutations on the interaction of the variants with cardiolipin have been investigated. The mutants are characterized by a subpopulation with non-native axial coordination, and are less stable than the wild type protein. Furthermore, the mutants lacking Lys72 and/or Lys79 do not bind cardiolipin and those lacking Lys73, although they form a complex with the phospholipid, do not show any peroxidase activity. These observations indicate that the Lys72, Lys73 and Lys79 residues stabilize the native axial Met80-Fe(III) coordination as well as the tertiary structure of cytochrome c. Moreover, while Lys72 and Lys79 are critical for cytochrome c/cardiolipin recognition, the simultaneous presence of Lys72, Lys73 and Lys79 is necessary for peroxidase activity of cardiolipin-bound cytochrome c
Multiparametric magnetic resonance imaging for the differential diagnosis between granulomatous prostatitis and prostate cancer: a literature review to an intriguing diagnostic challenge
Multiparametric magnetic resonance imaging (mpMRI) is currently the most effective diagnostic tool for detecting prostate cancer (PCa) and evaluating adenocarcinoma-mimicking lesions of the prostate gland, among which granulomatous prostatitis (GP) represents the most interesting diagnostic challenge. GP consists of a heterogeneous group of chronic inflammatory lesions that can be differentiated into four types: idiopathic, infective, iatrogenic, and associated with systemic granulomatous disease. The incidence of GP is growing due to the increase in endourological surgical interventions and the adoption of intravesical instillation of Bacillus Calmette-Guerin in patients with non-muscle invasive bladder cancer; therefore, the difficulty lies in identifying specific features of GP on mpMRI to avoid the use of transrectal prostate biopsy as much as possible
Transverse prostate maximum sectional area can predict clinically significant prostate cancer in PI-RADS 3 lesions at multiparametric magnetic resonance imaging
BackgroundTo evaluate multiparametric magnetic resonance imaging (mpMRI) parameters, such as TransPA (transverse prostate maximum sectional area), TransCGA (transverse central gland sectional area), TransPZA (transverse peripheral zone sectional area), and TransPAI (TransPZA/TransCGA ratio) in predicting prostate cancer (PCa) in prostate imaging reporting and data system (PI-RADS) 3 lesions. MethodsSensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), the area under the receiver operating characteristic curve (AUC), and the best cut-off, were calculated. Univariate and multivariate analyses were carried out to evaluate the capability to predict PCa. ResultsOut of 120 PI-RADS 3 lesions, 54 (45.0%) were PCa with 34 (28.3%) csPCas. Median TransPA, TransCGA, TransPZA and TransPAI were 15.4cm(2), 9.1cm(2), 5.5cm(2) and 0.57, respectively. At multivariate analysis, location in the transition zone (OR=7.92, 95% CI: 2.70-23.29, P<0.001) and TransPA (OR=0.83, 95% CI: 0.76-0.92, P<0.001) were independent predictors of PCa. The TransPA (OR=0.90, 95% CI: 0.082-0.99, P=0.022) was an independent predictor of csPCa. The best cut-off of TransPA for csPCa was 18 (Sensitivity 88.2%, Specificity 37.2%, PPV 35.7%, NPV 88.9%). The discrimination (AUC) of the multivariate model was 0.627 (95% CI: 0.519-0.734, P<0.031). ConclusionsIn PI-RADS 3 lesions, the TransPA could be useful in selecting patients requiring biopsy
Enhancing electron correlation at a 3D ferromagnetic surface
Spin-resolved momentum microscopy and theoretical calculations are combined beyond the one-electron approximation to unveil the spin-dependent electronic structure of the interface formed between iron (Fe) and an ordered oxygen (O) atomic layer, and an adsorbate-induced enhancement of electronic correlations is found. It is demonstrated that this enhancement is responsible for a drastic narrowing of the Fe d-bands close to the Fermi energy (EF) and a reduction of the exchange splitting, which is not accounted for in the Stoner picture of ferromagnetism. In addition, correlation leads to a significant spin-dependent broadening of the electronic bands at higher binding energies and their merging with satellite features, which are manifestations of a pure many-electron behavior. Overall, adatom adsorption can be used to vary the material parameters of transition metal surfaces to access different intermediate electronic correlated regimes, which will otherwise not be accessible. The results show that the concepts developed to understand the physics and chemistry of adsorbate–metal interfaces, relevant for a variety of research areas, from spintronics to catalysis, need to be reconsidered with many-particle effects being of utmost importance. These may affect chemisorption energy, spin transport, magnetic order, and even play a key role in the emergence of ferromagnetism at interfaces between non-magnetic systems
Enhancing electron correlation at a 3d ferromagnetic surface
Spin-resolved momentum microscopy and theoretical calculations are combined beyond the one-electron approximation to unveil the spin-dependent electronic structure of the interface formed between iron (Fe) and an ordered oxygen (O) atomic layer, and an adsorbate-induced enhancement of electronic correlations is found. It is demonstrated that this enhancement is responsible for a drastic narrowing of the Fe d-bands close to the Fermi energy (EF) and a reduction of the exchange splitting, which is not accounted for in the Stoner picture of ferromagnetism. In addition, correlation leads to a significant spin-dependent broadening of the electronic bands at higher binding energies and their merging with satellite features, which are manifestations of a pure many-electron behavior. Overall, adatom adsorption can be used to vary the material parameters of transition metal surfaces to access different intermediate electronic correlated regimes, which will otherwise not be accessible. The results show that the concepts developed to understand the physics and chemistry of adsorbate–metal interfaces, relevant for a variety of research areas, from spintronics to catalysis, need to be reconsidered with many-particle effects being of utmost importance. These may affect chemisorption energy, spin transport, magnetic order, and even play a key role in the emergence of ferromagnetism at interfaces between non-magnetic systems
PSMA-PET Guided Treatment in Prostate Cancer Patients with Oligorecurrent Progression after Previous Salvage Treatment
Background: Prostate Specific Membrane Antigen-Positron Emission Tomography (PSMA-PET) is used to select recurrent prostate cancer (PCa) patients for metastases-directed therapy (MDT). We aimed to evaluate the oncologic outcomes of second-line PSMA-guided MDT in oligo-recurrent PCa patients. Methods: we performed a retrospective analysis of 113 recurrent PCa after previous radical prostatectomy and salvage therapies with oligorecurrent disease at PSMA-PET (≤3 lesions in N1/M1a-b) in three high-volume European centres. Patients underwent second-line salvage treatments: MDT targeted to PSMA (including surgery and/or radiotherapy), and the conventional approach (observation or Androgen Deprivation Therapy [ADT]). Patients were stratified according to treatments (MDT vs. conventional approach). Patients who underwent MDT were stratified according to stage in PSMA-PET (N1 vs. M1a-b). The primary outcome of the study was Progression-free survival (PFS). Secondary outcomes were Metastases-free survival (MFS) and Castration Resistant PCa free survival (CRPC-FS). Kaplan-Meier analyses assessed PFS, MFS and CRPC-FS. Multivariable Cox regression models identified predictors of progression and metastatic disease. Results: Overall, 91 (80%) and 22 (20%) patients were treated with MDT and the conventional approach, respectively. The median follow-up after PSMA-PET was 31 months. Patients who underwent MDT had a similar PFS compared to the conventional approach (p = 0.3). Individuals referred to MDT had significantly higher MFS and CRPC-FS compared to those who were treated with the conventional approach (73.5% and 94.7% vs. 30.5% and 79.5%; all p ≤ 0.001). In patients undergoing MDT, no significant differences were found for PFS and MFS according to N1 vs. M1a-b disease, while CRPC-FS estimates were significantly higher in patients with N1 vs. M1a-b (100% vs. 86.1%; p = 0.02). At multivariable analyses, age (HR = 0.96) and ADT during second line salvage treatment (HR = 0.5) were independent predictors of PFS; MDT (HR 0.27) was the only independent predictor of MFS (all p ≤ 0.04) Conclusion: Patients who underwent second-line PSMA-guided MDT experienced higher MFS and CRPC-FS compared to men who received conventional management
Role of Local and/or Metastasis-directed Therapy in Patients with Hormone-sensitive M1a Prostate Cancer:A Systematic Review
CONTEXT: It remains unclear whether men with hormone-sensitive prostate cancer (PCa) metastasized to nonregional lymph nodes (M1a) benefit from prostate-directed therapy (PDT) and/or metastasis-directed therapy (MDT). OBJECTIVE: To systematically summarize the literature regarding oncological outcomes of de novo and recurrent M1a PCa patients treated with PDT and/or MDT. EVIDENCE ACQUISITION: We searched Medline (Ovid), Embase, and Scopus according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines for reports on oncological outcomes of de novo or recurrent hormone-sensitive M1a PCa patients treated with PDT (radical prostatectomy or radiotherapy) and/or MDT (nodal radiotherapy or salvage lymph node dissection) with or without androgen deprivation therapy. A descriptive data synthesis and a methodological quality assessment were performed to evaluate the impact of PDT and/or MDT on survival in M1a PCa patients. EVIDENCE SYNTHESIS: A total of 6136 articles were screened and 24 studies were included in this systematic review. In de novo M1a PCa patients, PDT was associated with improved oncological outcomes compared with no PDT. In recurrent M1a PCa, MDT could delay the need for systemic treatment in a selection of patients, but high-level evidence from prospective phase III randomized controlled trials is still awaited. CONCLUSIONS: This systematic review summarized the limited literature data on the management of M1a PCa. Subgroup analyses suggest a role for PDT plus systemic therapy in de novo M1a PCa. MDT to distant nodal metastases delayed the need for systemic therapy in recurrent disease, but robust data are lacking. The predominantly retrospective nature of the included studies and significant heterogeneity in study designs limit the strength of evidence. PATIENT SUMMARY: We reviewed the treatment of patients with prostate cancer that has spread to lymph nodes outside the pelvis without metastases in other organ systems. There is evidence that treatment of the primary prostate tumor improves outcomes in well-selected patients and that treatment targeting distant lymph node metastases can delay the start of systemic treatment.</p
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