Computed tomography-derived fractional flow reserve (FFRCT) has no additional clinical impact over the anatomical Coronary Artery Disease - Reporting and Data System (CAD-RADS) in real-world elective healthcare of coronary artery disease.

AIM: To evaluate the impact of computed tomography-derived fractional flow reserve (FFRCT) compared to the anatomical Coronary Artery Disease - Reporting and Data System (CAD-RADS) in the elective assessment of coronary artery disease in real-world cardiology practise. MATERIALS AND METHODS: A retrospective review was undertaken of 1,239 coronary CT examinations from August 2018 to December 2019 with a minimum follow-up period of 1 year. Coronary disease was classified according to the CAD-RADS system. A non-occlusive ≥30% maximum diameter stenosis was considered eligible for FFRCT. Lesion-specific FFRCT and FFR were considered positive if ≤ 0.80. The patients were followed up using the hospital radiology information system and the electronic patient record. A positive outcome was defined by a subsequent invasive angiogram (ICA) showing disease requiring revascularisation or FFR ≤0.80 or a positive stress test or medical therapy for angina in CAD-RADS 4. RESULTS: Of the 1,145 analysable studies (mean follow up 618 ± 153 days) the incidence of a positive result was 7% with a 5.4% elective revascularisation rate. Two hundred and forty-five patients (CAD-RADS 2-4) had FFRCT. FFRCT reduced the accuracy of the CAD-RADS grade from 91% to 78.4% (p<0.001). In CAD-RADS 2, the accuracy is reduced from 99% to 90.7% (p=0.005), and in CAD-RADS 3 from 93.9% to 67.7% (p<0.001). In CAD-RADS 4, FFRCT increases accuracy from 69.4% to 75.5% (p=0.025), but 89.8% of FFRCT are positive and specificity is low (26.7%). CONCLUSION: In the present "real-world" practise, FFRCT does not improve standard radiological assessment of coronary disease graded by the CAD-RADS alone.

Disentangling Electronic and Vibrational Coherence in the Phycocyanin-645 Light-Harvesting Complex.

Energy transfer between chromophores in photosynthesis proceeds with near-unity quantum efficiency. Understanding the precise mechanisms of these processes is made difficult by the complexity of the electronic structure and interactions with different vibrational modes. Two-dimensional spectroscopy has helped resolve some of the ambiguities and identified quantum effects that may be important for highly efficient energy transfer. Many questions remain, however, including whether the coherences observed are electronic and/or vibrational in nature and what role they play. We utilize a two-color, four-wave mixing experiment with control of the wavelength and polarization to selectively excite specific coherence pathways. For the light-harvesting complex PC645, from cryptophyte algae, we reveal and identify specific contributions from both electronic and vibrational coherences and determine an excited-state structure based on two strongly coupled electronic states and two vibrational modes. Separation of the coherence pathways also uncovers the complex evolution of these coherences and the states involved.

Coherent Vibronic Coupling in Light-Harvesting Complexes from Photosynthetic Marine Algae.

Observations of long-lived coherences in photosynthetic light-harvesting complexes utilize short pulses with broad spectral bandwidths to coherently excite multiple transitions and coherent superpositions. In order to identify the role that such quantum effects might play in efficient energy transfer, however, an alternative approach is required. We have developed a technique for two-color photon echo spectroscopy to selectively excite the pathway of interest and measure its evolution in the absence of any other excitation. We use this technique to excite a coherence pathway in phycocyanin-645 from cryptophyte algae and measure the dynamics of this coherence. A decoherence time of 500 fs was measured, and clear signatures for strong coupling between the electronic states and phonon modes were observed, allowing coherent coupling between otherwise nonresonant transitions. This provides detailed experimental evidence of the long-lived coherences and the nature of the quantum mechanical interactions between electronic states and phonon modes in phycocyanin-645 from cryptophyte marine algae.

Megakaryoblastic transformation of chronic granulocytic leukaemia. An electron microscopy and cytochemial study.

Morphological, cytochemical, and ultrastructural electron microscopic (EM) studies were performed on blood and bone-marrow cells of case of Ph1-positive chronic ganulocytic leukaemia in megakaryocytic acute transformation. The entire leukaemic cell population was found to consist and of megakaryoblasts and megakaryocytes. Intermediate stages of maturation between blasts and micromegakaryocytes were observed at EM level.