Universal stability of coherently diffusive 1D systems with respect to decoherence

Static disorder in a 3D crystal degrades the ideal ballistic dynamics until it produces a localized regime. This Metal-Insulator Transition is often preceded by coherent diffusion. By studying three different paradigmatic 1D models, the Harper-Hofstadter-Aubry-Andr\'e and the Fibonacci tight-binding chains, and the power-banded random matrix model, we show that whenever coherent diffusion is present, transport is exceptionally stable against decoherent noise. This is completely at odds with what happens for ballistic and localized dynamics, where the diffusion coefficient strongly depends on the environmental decoherence. A universal dependence of the diffusion coefficient on the decoherence strength is analytically derived: the diffusion coefficient remains almost decoherence-independent until the coherence time becomes comparable with the mean elastic scattering time. Thus, systems with a quantum diffusive regime could be used to design stable quantum wires and may explain the functionality of many biological systems, which often operate at the border between the ballistic and localized regimes.Comment: Main: 8 pages, 3 figures. Supplementary: 17 pages, 10 figure

Extraordinary electrical conductance through amorphous non-conducting polymers under vibrational strong coupling

Achieving electrical conductance in amorphous non-doped polymers is a challenging task. Here, we show that vibrational strong coupling of the aromatic C-H(D) out-of-plane bending modes of polystyrene, deuterated polystyrene, and poly (benzyl methacrylate) to the vacuum electromagnetic field of the cavity enhance the electrical conductivity by at least six orders of magnitude compared to the uncoupled polymers. The conductance is thermally activated at the onset of strong coupling. It becomes temperature and cavity path length independent at the highest coupling strengths, giving rise to the extraordinary electrical conductance in these polymers. The electrical characterizations are performed without external light excitation, demonstrating the role of quantum light in enhancing the long-range coherent transport even in amorphous non-conducting polymers.Comment: Sunil Kumar and Subha Biswas contributed equall

Efficient light harvesting and photon sensing via engineered cooperative effects

Efficient devices for light harvesting and photon sensing are fundamental building blocks of basic energy science and many essential technologies. Recent efforts have turned to biomimicry to design the next generation of light-capturing devices, partially fueled by an appreciation of the fantastic efficiency of the initial stages of natural photosynthetic systems at capturing photons. In such systems extended excitonic states are thought to play a fundamental functional role, inducing cooperative coherent effects, such as superabsorption of light and supertransfer of photoexcitations. Inspired by this observation, we design an artificial light-harvesting and photodetection device that maximally harnesses cooperative effects to enhance efficiency. The design relies on separating absorption and transfer processes (energetically and spatially) in order to overcome the fundamental obstacle to exploiting cooperative effects to enhance light capture: the enhanced emission processes that accompany superabsorption. This engineered separation of processes greatly improves the efficiency and the scalability of the system

Early Embryonic Vascular Patterning by Matrix-Mediated Paracrine Signalling: A Mathematical Model Study

During embryonic vasculogenesis, endothelial precursor cells of mesodermal origin known as angioblasts assemble into a characteristic network pattern. Although a considerable amount of markers and signals involved in this process have been identified, the mechanisms underlying the coalescence of angioblasts into this reticular pattern remain unclear. Various recent studies hypothesize that autocrine regulation of the chemoattractant vascular endothelial growth factor (VEGF) is responsible for the formation of vascular networks in vitro. However, the autocrine regulation hypothesis does not fit well with reported data on in vivo early vascular development. In this study, we propose a mathematical model based on the alternative assumption that endodermal VEGF signalling activity, having a paracrine effect on adjacent angioblasts, is mediated by its binding to the extracellular matrix (ECM). Detailed morphometric analysis of simulated networks and images obtained from in vivo quail embryos reveals the model mimics the vascular patterns with high accuracy. These results show that paracrine signalling can result in the formation of fine-grained cellular networks when mediated by angioblast-produced ECM. This lends additional support to the theory that patterning during early vascular development in the vertebrate embryo is regulated by paracrine signalling

Adeguamento cardiorespiratorio e metabolico all'esercizio sottomassimale e massimale in atleti poliomielitici

Many individuals who have had poliomyelitis are involved in muscular exercise and are frequently evaluated in the Sports Medical Centres in our country. This paper was aimed to evaluate whether, by means of submaximal and maximal ergometric tests, the existence of a post-polio syndrome (PPS) can be assessed. The PPS includes muscle atrophy, general fatigue, weakness and muscle, joint pain and affects 20-30% of the patients 30-40 years after the initial bout with the disease. Moreover the fitness level and the cardiorespiratory adjustments to exercise were assessed in poliomyelitis individuals of various ages and different training levels. Two groups of polio athletes with lesions restricted to the lower limbs were recruited. Group A, males, n = 9; 46 \ub1 4.8 (SD) years, initial bout at age 1-6; walking aids required, all involved in the 'crutch soccer' sport since 30 years. Group B, males, n = 8; 30 \ub1 3 years, initial bout at age 1-5, wheelchair users, elite basket ball players. Ac and Bc groups were the corresponding healthy sedentary controls. After medical examination and respiratory function tests, the cardiorespiratory adjustments to submaximal and maximal exercise were assessed at steady state on the wheelchair ergometer. In the controls the peak of oxygen (VO 2p) was also determined during bicycle exercise. In A group no signs or symptoms of post-polio syndrome were detected. HR/VO 2 and VE/VO 2 relationships during submaximal exercises were similar in polio and healthy controls. VO 2p peak (ml min 1\ub7kg -1) on the wheelchair ergometer was 20.5 \ub1 2 (SE) in A; 19.6 \ub1 3 in Ac; 30.3 \ub1 1 in B and 20.8 \ub1 3 in Bc: On the bicycle VO 2p was 28.8 \ub1 3 in Ac and 31.3 \ub1 3 in Bc. Ventilatory equivalent and oxygen pulse were similar in all groups. We conclude that presumably training for many years may help to prevent the post-polio syndrome. Moreover, basket ball played at high level substantially improves the fitness level of polio individuals and may counteract the expected negative evolution of the muscular function of these patients

Bio-inspired natural sunlight-pumped lasers

Even though sunlight is by far the most abundant renewable energy source available to humanity, its dilute and variable nature has kept efficient ways to collect, store, and distribute this energy tantalisingly out of reach. Turning the incoherent energy supply provided by the Sun into a coherent laser beam would overcome several of the practical limitations inherent in using sunlight as a source of clean energy: laser beams travel nearly losslessly over large distances, and they are effective at driving chemical reactions which convert sunlight into chemical energy. Here we propose a bio-inspired blueprint for a novel type of laser with the aim of upgrading unconcentrated natural sunlight into a coherent laser beam. Our proposed design constitutes a novel and different path towards sunlight-pumped lasers. In order to achieve lasing with the extremely dilute power provided by natural sunlight, we here propose a laser medium comprised of molecular aggregates inspired by the architecture of natural photosynthetic complexes. Such complexes exhibit a very large internal efficiency in harvesting photons from a power source as dilute as natural sunlight. Specifically, we consider a hybrid structure, where photosynthetic complexes in purple bacteria (Rhodobacter sphaeroides) surround a suitably engineered molecular dimer composed of two strongly coupled chromophores. We show that if pumped by the surrounding photosynthetic complex, which efficiently collects and concentrates solar energy, the core dimer structure can reach population inversion, and reach the lasing threshold under natural sunlight. The design principles proposed here will also pave the way for developing other bio-inspired quantum devices.Comment: Main text: 24 pages, 6 figures. Supplementary Material: 25 pages, 9 figure

A RARE CASE OF AKI SUSTAINED BY SEGMENTAL ARTERIAL MEDIOLYSIS WITH BILATERAL RENAL INFARCTION

Case repor

Everolimus-associated alveolar hemorrage relapse after drug discontinuation in a kidney transplant recipient

Everolimus-associated alveolar hemorrage relapse after drug discontinuation in a kidney transplant recipien

Contrast-induced encephalopathy after carotid percutaneous transluminal angioplasty in a patient with end stage renal disease undergoing peritoneal dialysis

Contrast-induced encephalopathy after carotid percutaneous transluminal angioplasty in a patient with end stage renal disease undergoing peritoneal dialysi