Cooling-Induced Order-Disorder Phase Transition in CsPbBr Nanocrystal Superlattices.

Perovskite nanocrystal superlattices are being actively studied after reports have emerged on collective excitonic properties at cryogenic temperatures, where energetic disorder is minimized due to the frozen lattice vibrations. However, an important issue related to structural disorder of superlattices at low temperatures has received little attention to date. In this work, it is shown that CsPbBr nanocrystal superlattices undergo a reversible order-disorder transition upon cooling to 90 K.

Fate of Optical Excitons in FAPbI Nanocube Superlattices.

Understanding the nature of the photoexcitation and ultrafast charge dynamics pathways in organic halide perovskite nanocubes and their aggregation into superlattices is key for potential applications as tunable light emitters, photon-harvesting materials, and light-amplification systems. In this work, we apply two-dimensional coherent electronic spectroscopy (2DES) to track in real time the formation of near-infrared optical excitons and their ultrafast relaxation in CH(NH)PbI nanocube superlattices. Our results unveil that the coherent ultrafast dynamics is limited by the combination of the inherent short exciton decay time (≃40 fs) and the dephasing due to the coupling with selective optical phonon modes at higher temperatures.

Halide Perovskite Artificial Solids as a New Platform to Simulate Collective Phenomena in Doped Mott Insulators.

The development of quantum simulators, artificial platforms where the predictions of many-body theories of correlated quantum materials can be tested in a controllable and tunable way, is one of the main challenges of condensed matter physics. Here we introduce artificial lattices made of lead halide perovskite nanocubes as a new platform to simulate and investigate the physics of correlated quantum materials. We demonstrate that optical injection of quantum confined excitons in this system realizes the two main features that ubiquitously pervade the phase diagram of many quantum materials: collective phenomena, in which long-range orders emerge from incoherent fluctuations, and the excitonic Mott transition, which has one-to-one correspondence with the insulator-to-metal transition described by the repulsive Hubbard model in a magnetic field.

Therapeutic Strategies and Clinical Outcome in Papillary Thyroid Microcarcinoma: A Multicenter Observational Study.

Purpose: Papillary thyroid microcarcinoma (MPTC) has an excellent prognosis. We aimed to evaluate the evolution of therapeutic strategies over time and the clinical outcome of MPTC.

Methods: In this retrospective multicenter observational study in a northwest Italian region, patients with intrathyroidal, unifocal tumor ≤1 cm in size, incidentally found at histology or preoperative cytology diagnosis, were included.

Prevalence of post-partum thyroiditis in Liguria (Italy): an observational study.

Background: Post-partum thyroiditis (PPT) is an autoimmune disorder occurring within the first year following delivery. A variable prevalence has been reported in different surveys. We prospectively evaluated PPT prevalence and outcome in a cohort of pregnant women living in a well-defined geographic area.

Lowered circannual urinary melatonin concentrations in episodic cluster headache.

The circannual secretion of melatonin in 14 Swedish and 15 Italian patients suffering from episodic cluster headache was compared with 14 Swedish and 15 Italian healthy controls matched for sex and age. Overnight samples of urine were collected once a month from 8 to 14 months and kept at -20 degrees C until analysed with RIA. The melatonin concentrations in nocturnal urine were permanently low in cluster headache and there was no consistent change of the melatonin concentration in relation to cluster periods occurring during the study.

[The neuroendocrine aspects of chronic alcoholism: the effect of alcohol intake and its withdrawal].

Neuroendocrine dysfunctions, in part similar to those found in depression, are present in chronic alcoholism. The aim of this investigation was to evaluate the effects of chronic alcohol intake on cortisol secretion in basal conditions, after dexamethasone (DXT) suppression or corticotropin (ACTH) stimulation in 10 alcoholic men, during active drinking and after two weeks of alcohol withdrawal. The 24-hour, day- and night-time urinary cortisol and melatonin levels, and the effects of thyrotropin releasing hormone (TRH) on thyrotropin (TSH) and prolactin (PRL) secretions were studied in the same subjects.

Urine melatonin in alcoholic patients: a marker of alcohol abuse?

Ethanol is known to alter central neurotransmission and endocrine functions. Urine melatonin was studied in 10 male chronic alcoholic patients, before and after two weeks of controlled alcohol abstinence, and in sex and age matched healthy controls. In both groups, 24-hour urines were collected in two fractions corresponding to day- (D) (08:00-20:00) and night- (N) (20:00-08:00) time.

TSH circadian secretions in aged men and effect of phosphatidylserine treatment.

In 20 euthyroid aged men (from 65 to 85 years of age) no significant circadian periodicity of thyrotropin (TSH) secretion has been shown by the population mean cosinor method. At the end of a period of 30 days of hospitalization the cosinor evaluation of TSH secretion showed a restored highly significant (p less than 0.001) circadian rhythmicity in phosphatidylserine (PS) (400 mg/daily) treated group (10 aged subjects).

Cholinergic modulation of growth hormone-releasing hormone effects on growth hormone secretion in dementia.

An impairment of cholinergic and somatostatinergic neurotransmission have been reported in dementia. Both acetylcholine and somatostatin are involved in the regulation of growth hormone (GH) secretion. The effects of GH-releasing hormone (GHRH) 1-44 on GH release have been studied before and after the pretreatment with pyridostigmine or pirenzepine in subjects with senile dementia of the Alzheimer type, multi-infarct dementia and mixed dementia.

Cluster headache in the male: sex steroid pattern and gonadotropic response to luteinizing hormone releasing hormone.

Serum testosterone, dihydrotestosterone, delta 4-androstendione and 17 beta-estradiol, sex hormone binding globulin (SHBG) and gonadotropic response to luteinizing hormone releasing hormone (LHRH) were studied in 34 male subjects with episodic or chronic cluster headache (CH). The sex steroid free fractions and those bound to SHBG and albumin were determined by a simulatory computerized method based on the mass action law. Individual steroid values were dispersed over a wide range in CH patients.

Thyrotropin and prolactin responses to different doses of thyrotropin-releasing hormone in depression.

The effects of low doses of thyrotropin-releasing hormone (TRH, 50 and 200 micrograms) on thyrotropin (TSH) and prolactin levels have been studied in depressed women and compared with the depressive condition and with the results of the dexamethasone suppression test (DST). TRH administration elicited blunted hormonal responses that were not correlated either with the age of the patients or with DST results. Different effects were observed in subgroups of depressive patients classified according to DSM III and ICD.

Thyroid-stimulating hormone and prolactin responses to thyrotropin-releasing hormone in common migraine.

Intravenous administration of 50 micrograms or 200 micrograms thyrotropin-releasing hormone (TRH) to men with common migraine elicited blunted prolactin (PRL) responses, when compared with healthy controls. The thyroid-stimulating hormone (TSH) response was enhanced after 50 micrograms TRH in the migraineurs, but not after 200 micrograms. The physiologic TSH dose-response relationship was abolished in migraine sufferers.