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We have investigated the mechanism of exciton-exciton annihilation in organic lanthanide complexes by measuring the excitation density dependence of photoluminescence yield in neat films of a model europium chelate. The observed luminescence efficiency reduction at high excitation intensities has been attributed to the operation of the mutual annihilation of the ligand singlet excitons. The second order interaction rate constant, the exciton diffusivity, and the singlet exciton diffusion length in this material have been determined. These results were used to evaluate the role of exciton annihilation in organic light emitting diodes, lanthanide-based organic lasers, and light up-converters. Indications concerning the optimization of the performances of such devices have also been given. [ABSTRACT FROM AUTHOR]

Hepatic cysts have become increasingly frequent findings thanks to the improvement in diagnostic investigations. Distinction has to be made between congenital hepatic cysts (like liver cyst, PLCD) and acquired forms (such as a parasitic cyst and a cyst occurring as part of a neoplastic process) (1). When a simple hepatic cyst becomes symptomatic, when its size is > 4 cm or when there is some radiological suspicion of malignancy (thick wall, peripheral enhancement on CT/MRI) surgical management is indicated and relies on a variety of techniques (2). Presently the two most common techniques are percutaneous aspiration with sclerotherapy and laparoscopic fenestration. The use of laparoscopic approach has achieved, in the last years, some great results, for it shortens hospital stay, involves minimal invasiveness and offers low recurrence rate. We report three cases of symptomatic hepatic cysts successfully treated by using laparoscopic procedure. KEY WORDS: Laparoscopic deroofing, Sclerotherapy, Simple hepatic cysts.

Controlling the flow of electrical current at the nanoscale typically requires complex top-down approaches. Here, a bottom-up approach is employed to demonstrate resistive switching within molecular wires that consist of double-helical metallopolymers and are constructed by self-assembly. When the material is exposed to an electric field, it is determined that ≈25% of the copper atoms oxidize from Cu I to Cu II , without rupture of the polymer chain. The ability to sustain such a high level of oxidation is unprecedented in a copper-based molecule: it is made possible here by the double helix compressing in order to satisfy the new coordination geometry required by Cu II . This mixed-valence structure exhibits a 10 4 -fold increase in conductivity, which is projected to last on the order of years. The increase in conductivity is explained as being promoted by the creation, upon oxidation, of partly filled d z 2 orbitals aligned along the mixed-valence copper array; the long-lasting nature of the change in conductivity is due to the structural rearrangement of the double-helix, which poses an energetic barrier to re-reduction. This work establishes helical metallopolymers as a new platform for controlling currents at the nanoscale., (© 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Hybrid organic-inorganic perovskites allow the synthesis of high-quality, nanostructured semiconducting films via easily accessible solution-based techniques. This has allowed tremendous development in optoelectronic applications, primarily solar cells and light-emitting diodes. Allowed by the ease of access to nanostructure, chirality has recently been introduced in semiconducting perovskites as a promising way to obtain advanced control of charge and spin and for developing circularly polarized light sources. Circular polarization of photoluminescence (CPL) is a powerful tool to probe the electronic structure of materials. However, CPL in chiral perovskites has been scarcely investigated, and a study in bulk thin films and at room temperature is still missing. In this work, we fabricate bromine-based chiral perovskites by using a bulky chiral organic cation mixed with CsBr, resulting in Ruddlesden-Popper perovskite thin films. We measure CPL on these films at room temperature and, by using unpolarized photoexcitation, we record a degree of circular polarization of photoluminescence in the order of 10 -3 and provide a full spectral characterization of CPL. Our results show that chirality is imparted on the electronic structure of the semiconductor; we hypothesize that the excess in polarization of emitted light originates from the charge in the photogenerated Wannier exciton describing an orbit in a symmetry-broken environment. Furthermore, our experiments allow the direct measurement of the magnetic dipole moment of the optical transition, which we estimate to be ≥0.1 μ B . Finally, we discuss the implications of our findings on the development of chiral semiconducting perovskites as sources of circularly polarized light.

Despite sustained research, application of lead halide perovskites in field-effect transistors (FETs) has substantial concerns in terms of operational instabilities and hysteresis effects which are linked to its ionic nature. Here, we investigate the mechanism behind these instabilities and demonstrate an effective route to suppress them to realize high-performance perovskite FETs with low hysteresis, high threshold voltage stability (ΔV t < 2 V over 10 hours of continuous operation), and high mobility values >1 cm 2 /V·s at room temperature. We show that multiple cation incorporation using strain-relieving cations like Cs and cations such as Rb, which act as passivation/crystallization modifying agents, is an effective strategy for reducing vacancy concentration and ion migration in perovskite FETs. Furthermore, we demonstrate that treatment of perovskite films with positive azeotrope solvents that act as Lewis bases (acids) enables a further reduction in defect density and substantial improvement in performance and stability of n-type (p-type) perovskite devices., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Covalent organic frameworks (COFs) are an emerging class of highly tuneable crystalline, porous materials. Here we report the first COFs that change their electronic structure reversibly depending on the surrounding atmosphere. These COFs can act as solid-state supramolecular solvatochromic sensors that show a strong colour change when exposed to humidity or solvent vapours, dependent on vapour concentration and solvent polarity. The excellent accessibility of the pores in vertically oriented films results in ultrafast response times below 200 ms, outperforming commercially available humidity sensors by more than an order of magnitude. Employing a solvatochromic COF film as a vapour-sensitive light filter, we demonstrate a fast humidity sensor with full reversibility and stability over at least 4000 cycles. Considering their immense chemical diversity and modular design, COFs with fine-tuned solvatochromic properties could broaden the range of possible applications for these materials in sensing and optoelectronics.

Self-assembled helical polymers hold great promise as new functional materials, where helical handedness controls useful properties such as circularly polarized light emission or electron spin. The technique of subcomponent self-assembly can generate helical polymers from readily prepared monomers. Here we present three distinct strategies for chiral induction in double-helical metallopolymers prepared via subcomponent self-assembly: (1) employing an enantiopure monomer, (2) polymerization in a chiral solvent, (3) using an enantiopure initiating group. Kinetic and thermodynamic models were developed to describe the polymer growth mechanisms and quantify the strength of chiral induction, respectively. We found the degree of chiral induction to vary as a function of polymer length. Ordered, rod-like aggregates more than 70 nm long were also observed in the solid state. Our findings provide a basis to choose the most suitable method of chiral induction based on length, regiochemical, and stereochemical requirements, allowing stereochemical control to be established in easily accessible ways.

Perovskite-based optoelectronic devices have been rapidly developing in the past 5 years. Since the first report, the external quantum efficiency (EQE) of perovskite light-emitting diodes (PeLEDs) has increased rapidly through the control of morphology and structure from 0.1% to more than 11%. Here, we report the use of various conjugated polyelectrolytes (CPEs) as the hole injection layer in PeLEDs. In particular, we find that poly[2,6-(4,4-bis-potassium butanylsulfonate)-4 H-cyclopenta-[2,1- b;3,4- b']-dithiophene)] (PCPDT-K) transfers holes effectively, blocks electron transport from the perovskite to the underlying ITO layer, and reduces luminescence quenching at the perovskite/PCPDT-K interface. Our optimized PeLEDs with PCPDT-K show enhanced EQE by a factor of approximately 4 compared to control PeLEDs with PEDOT:PSS, reaching EQE values of 5.66%, and exhibit improved device stability.

Organic-inorganic hybrid perovskites are emerging as promising emitting materials due to their narrow full-width at half-maximum emissions, color tunability, and high photoluminescence quantum yields (PLQYs). However, the thermal generation of free charges at room temperature results in a low radiative recombination rate and an excitation-intensity-dependent PLQY, which is associated with the trap density. Here, we report perovskite films composed of uniform nanosized single crystals (average diameter = 31.7 nm) produced by introducing bulky amine ligands and performing the growth at a lower temperature. By effectively controlling the crystal growth, we maximized the radiative bimolecular recombination yield by reducing the trap density and spatially confining the charges. Finally, highly bright and efficient green emissive perovskite light-emitting diodes that do not suffer from electroluminescence blinking were achieved with a luminance of up to 55 400 cd m -2 , current efficiency of 55.2 cd A -1 , and external quantum efficiency of 12.1%.

The molecular organization in thermally annealed films of poly(9,9-bis((S)-3,7-dimethyloctyl)-2,7-fluorene-alt-benzothiadiazole) is investigated using polarized light. Measurement of linear polarization in transmission and reflection as a function of layer thickness and orientation directly show a left handed cholesteric organization with a pitch length of 600 nm. Results are corroborated by measurements of circularly polarized reflection and generalized ellipsometry and are compared to calculations of the optical properties based on the Maugin-Oseen-DeVries model. For wavelengths near the lowest allowed optical transition, light with the same handedness as the cholesteric arrangement (left) is found to be reflected and transmitted with a probability higher than right circularly polarized light. The high transmission for left polarized light is interpreted as an optical manifestation of the Borrmann effect.

We demonstrate a facile route to obtain high and broad-band circular polarization of electroluminescence in single-layer polymer OLEDs. As a light-emitting material we use a donor-acceptor polyfluorene with enantiomerically pure chiral side-chains. We show that upon thermal annealing the polymer self-assembles into a multidomain cholesteric film. By varying the thickness of the polymer emitting layer, we achieve high levels of circular polarization of electroluminescence (up to 40% excess of right-handed polarization), which are the highest reported for polymer OLEDs not using chiral dopants or alignment layers. Mueller matrix ellipsometry shows strong optical anisotropies in the film, indicating that the circular polarization of luminescence arises mainly after the photon has been generated, through selective scattering and birefringence correlated in the direction of the initial linear polarization of the photon. Our work demonstrates that chirally substituted conjugated polymers can combine photonic and semiconducting properties in advanced optoelectronic devices.

The use of hybrid organic-inorganic perovskites in optoelectronic applications are attracting an interest because of their outstanding characteristics, which enable a remarkable enhancement of device efficiency. However, solution-processed perovskite crystals unavoidably contain defect sites that cause hysteresis in perovskite solar cells (PeSCs) and blinking in perovskite light-emitting diodes (PeLEDs). Here, we report significant beneficial effects using a new treatment based on amine-based passivating materials (APMs) to passivate the defect sites of methylammonium lead tribromide (MAPbBr 3 ) through coordinate bonding between the nitrogen atoms and undercoordinated lead ions. This treatment greatly enhanced the PeLED's efficiency, with an external quantum efficiency (EQE) of 6.2%, enhanced photoluminescence (PL), a lower threshold for amplified spontaneous emission (ASE), a longer PL lifetime, and enhanced device stability. Using confocal microscopy, we observed the cessation of PL blinking in perovskite films treated with ethylenediamine (EDA) due to passivation of the defect sites in the MAPbBr 3 .

Colorectal cancer (CRC) is one of the most common malignancies worldwide and the lung is one of the most frequent sites for CRC metastasis. The geriatric population is increasing, but clinical decision making is often influenced by the effect of aging. For this reason, the elderly population does not often receive potentially curative cancer treatments as offered to younger ones. From January 2000 to March 2016, 21 elderly patients (older than 75 years) underwent pulmonary resections for colorectal cancer pulmonary metastases. A postoperative morbidity rate of 23.8 % and a 30-day mortality rate of 4.8 % were reported. A cumulative overall survival of 34.19 ± 23.51 months (95 % CI 23.71-50.28) and a disease-free interval of 24.62 ± 23.79 months (95 % CI 6.44-39.56) were observed. By considering only R0 surgically resected patients, the 1-, 3- and 5-year OS were 94.1, 59.5 and 21.2 % with a mean overall survival and disease-free interval of 51.10 ± 7.82 and 42.75 ± 9.35, respectively. Concerning risk factors, an important correlation between the number of pulmonary metastases, surgical radicality and overall survival was reported (p = 0.030 and p = 0.005, respectively). In summary, according to our series, pulmonary metastasectomy in selected elderly CRC oligometastatic patients seems to be safe and effective.

A perovskite LED with a perovskite film treated under optimum thermal annealing conditions exhibits a significantly enhanced long-term stability with full coverage of the green electroluminescence emission due to the highly uniform morphology of the perovskite film., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Though the actual incidence of an adrenal oligometastasis is between 1.5 and 3.5 %, secondary adrenal neoplasms occur in less than 10 % patients with non-small cell lung cancer (NSCLC). According to 7° ed. TNM staging system, the presence of an adrenal metastasis (M1b disease) configures stage IV, which is usually associated with poor prognosis. We evaluated if metastasectomy in selected patients with oligometastatic disease improves overall survival. A 15-year retrospective study concerning patients with NSCLC was performed and an oligometastatic disease was found in 1.61 % of the patients. 18 adrenalectomies were performed. Clustering the population according to different therapeutic strategies, a benefit in terms of survival was found in patients who underwent adrenalectomy. A statistical relevance was found, indeed, between adrenalectomy (p < 0.01), metachronous disease (p < 0.01), the presence of a homolateral disease (p < 0.05) and overall survival. Adrenalectomy should be offered in selected patients with oligometastatic disease.

We investigate the photogeneration of polaron pairs (PPs) in neat films of the semicrystalline donor-acceptor semiconducting copolymer PCPDTBT. Carefully selecting the solution-processing procedures, we obtain films with different amounts of crystallinity and interchain aggregation. We compare the photogeneration of PPs between the films by monitoring their photoinduced absorption in ultrafast pump-probe experiments, selectively exciting nonaggregated or aggregated polymer chains. The direct photoexcitation of interchain π-aggregates results in prompt (<100 fs) charge generation. Compared to the case where nonaggregated chains are excited, we find an 8-fold increase in the prompt PP to singlet-exciton ratio. We also show that highly crystalline lamellar nanostructures not containing π-stacked or any light-absorbing aggregates do not improve the efficiency of PP photogeneration. Our results show that light absorption from interchain aggregates is highly beneficial for charge photogeneration in semiconducting polymers and should be taken into account when optimizing film morphologies for photovoltaic devices.

Molecular doping of conjugated polymers represents an important strategy for improving organic electronic devices. However, the widely reported low efficiency of doping remains a crucial limitation to obtain high performance. Here we investigate how charge transfer between dopant and donor-acceptor copolymers is affected by the spatial arrangement of the dopant molecule with respect to the copolymer repeat unit. We p-dope a donor-acceptor copolymer and probe its charge-sensitive molecular vibrations in films by infrared spectroscopy. We find that, compared with a related homopolymer, a four times higher dopant/polymer molar ratio is needed to observe signatures of charges. By DFT methods, we simulate the vibrational spectra, moving the dopant along the copolymer backbone and finding that efficient charge transfer occurs only when the dopant is close to the donor moiety. Our results show that the donor-acceptor structure poses an obstacle to efficient doping, with the acceptor moiety being inactive for p-type doping.

402 thoracoabdominal traumas have been observed since November 1998 and seven of these patients (1.7%) showed a diaphragmatic rupture. Four patients showed a right diaphragm rupture and three a left diaphragm rupture. Road traffic accidents were the main cause of trauma. Early diagnosis was performed in three patients (43%), a delayed diagnosis was made to the other patients (57%): one case was an intraoperative diagnosis (14.2%). Everyone had chest X rays and chest and upper abdomen CT scan. One patient had MRI on a late diagnosis. Thoracotomy was performed in all patients and one case (14.2%) of morbility and one (14.2%) of mortality were observed.

Pancreaticoduodenal artery (PD A) aneurysms are rare, with a reported incidence of 2% among all splanchnic artery aneurysms. Most of these lesions are undetectable until symptoms of rupture occur. In similar cases (65%), PDA rupture is usually associated with a high mortality rate, with fatal bleeding into the retroperitoneal space, intraperitoneal cavity or gastrointestinal tract. Clinical picture without rupture also has been reported (35%) and is often associated with atypic abdominal signs and symptoms or diagnosed incidentally on radiology studies. The Authors report a case of octogenarian patient with ruptured PDA aneurysm and bleeding into the retroperitoneal space presenting with stable clinical condition. Surgical treatment was performed successfully after radiological diagnosis of retroperitoneal haematoma with good outcome. Patients presenting catastrophic clinical condition need rapid resuscitation and emergency laparotomy: control of the bleeding site may be successful and aetiologycal diagnosis delayed after perioperative angiography. Further laparotomy is mandatory for a definitive treatment such as PDA obliteration or resection. An alternative therapy is the transcatheter embolization. In patients with relatively stable condition, radiological study is stressed. Anyway, the aneurysm should be obliterated whenever possible to avoid rebleeding or local complications such as erosion of the neighboring structure. In conclusion, an appropriate and early treatment lead to a good outcomes.

Videothoracoscopy can be used for diagnostic purposes when the other non-invasive methods are not satisfactory for an accurate histological diagnosis in lung and pleural pathology. The role of VTS was confirmed in the cases, observed from 1993 and surgically treated, which are herein discussed.

A correlation between the personality profile and the clinical history in lung cancer patients was studied. Selection of cases included in the sample only surgical patients with a medium educational level and a tested capability to understand a specific questionnaire. One hundred and seventy patients were selected and the so-called C.R.I.C.S. (Clinical-Rated Inventory of Character Style) was applied. Score variations were recorded after curative resection as well as during relapse. Changes in the character profile pattern were found in all subjects who experienced the disease and its surgical treatment. These changes occurred either in "regression"-with an increase of schizoid, narcissistic or hysterical aspects-or in a "positive evolution", with a decrease of paranoid traits and into a depressive position. The two groups of responses demonstrated a similar percentage.

The authors address the topic of acute acalculous cholecystitis and examine the related aetiopathogenetic and clinical problems, taking as their starting point two cases of the disease observed in their department.