Publications by authors named "Viti L"

Detecting electromagnetic radiation scattered from a tip-sample junction has enabled overcoming the diffraction limit and started the flourishing field of polariton nanoimaging. However, most techniques only resolve amplitude and relative phase of the scattered radiation. Here, we utilize field-resolved detection of ultrashort scattered pulses to map the dynamics of surface polaritons in both space and time.

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The development of advanced diabetes technology has permitted persons with type 1 diabetes mellitus to improve metabolic control significantly, particularly with the development of advanced hybrid closed-loop systems which have improved the quality of life by reducing hypoglycemia, decreasing macroangiopathy and microangiopathy-related complications, ameliorating HbA1c and improving glycemic variability. Despite the progression made over the past few decades, there is still significant margin for improvement to be made in terms of attaining appropriate metabolic control. Various factors are responsible for poor glycemic control including inappropriate carbohydrate counting, repeated bouts of hypoglycemia, hypoglycemia unawareness, cutaneous manifestations due to localized insulin use and prolonged use of diabetes technology, psychosocial comorbidities such as eating disorders or 'diabulimia', the coexistence of insulin resistance among people with type 1 diabetes and the inability to mirror physiological endogenous pancreatic insulin secretion appropriately.

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Aim: To assess the long-term glycaemic outcomes, with additional metrics, in adults with type 1 diabetes (T1D) using the Tandem t:slim X2 with Control-IQ technology advanced hybrid closed-loop (AHCL) system.

Methods: This was a single-centre, retrospective study involving 56 T1D patients who transitioned to the Tandem t:slim X2 with Control-IQ system. The primary and secondary endpoints consisted of variations in time in tight range (TiTR; 70-140 mg/dL) and the glycaemia risk index (GRI), respectively.

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Article Synopsis
  • Optical resonators are essential components in photonic systems, facilitating the development of meta-surfaces, sensors, and transmission filters.
  • Sub-wavelength resonators like planar split-ring resonators are significant for their capabilities in light manipulation and sensing, as well as for studying light-matter interactions.
  • The study employs near-field microscopy to investigate circular split-ring resonators with single layer graphene, leading to detailed mapping of electric field distributions which is crucial for applications like high harmonic generation.
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Hirata disease, also known as insulin autoimmune syndrome (IAS), is a rare cause of hypoglycemia, due to the presence of insulin autoantibodies (IAA) in the circulating blood. These antibodies are immunoglobulin G (IgG), making placental transfer to the fetus possible. To our knowledge, no reports of IAS have been previously described in the neonatal population.

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Polaritons in two-dimensional layered crystals offer an effective solution to confine, enhance and manipulate terahertz (THz) frequency electromagnetic waves at the nanoscale. Recently, strong THz field confinement has been achieved in a graphene-insulator-metal structure, exploiting THz plasmon polaritons (PPs) with strongly reduced wavelength (λ ≈ λ/66) compared to the photon wavelength λ. However, graphene PPs propagate isotropically, complicating the directional control of the THz field, which, on the contrary, can be achieved exploiting anisotropic layered crystals, such as orthorhombic black-phosphorus.

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Excitation of Dirac plasmon polaritons (DPPs) in bi-dimensional materials have attracted considerable interest in recent years, both from perspectives of understanding their physics and exploring their transformative potential for nanophotonic devices, including ultra-sensitive plasmonic sensors, ultrafast saturable absorbers, modulators, and switches. Topological insulators (TIs) represent an ideal technological platform in this respect because they can support plasmon polaritons formed by Dirac carriers in the topological surface states. Tracing propagation of DPPs is a very challenging task, particularly at terahertz (THz) frequencies, where the DPP wavelength becomes over one order of magnitude shorter than the free space photon wavelength.

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Unlabelled: Aim of this study is to evaluate any differences in VWF antigen, VWF activity and ADAMTS-13 activity before and after successful and non-successful Percutaneous Transluminal Angioplasty (PTA) in subjects with type 2 diabetes (T2DM) complicated by Chronic limb-threatening ischemia (CLTI) in diabetic foot vasculopathy.

Methods: In this prospective observational pilot study, we enrolled 35 T2DM subjects who underwent lower limb PTA. Transcutaneous oximetry was performed in all patients before and 6 weeks after PTA.

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Patched1 (PTCH1) is a tumor suppressor protein of the mammalian Hedgehog (HH) signaling pathway, implicated in embryogenesis and tissue homeostasis. PTCH1 inhibits the G protein-coupled receptor Smoothened (SMO) via a debated mechanism involving modulating ciliary cholesterol accessibility. Using extensive molecular dynamics simulations and free energy calculations to evaluate cholesterol transport through PTCH1, we find an energetic barrier of ~15 to 20 kilojoule per mole for cholesterol export.

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Article Synopsis
  • Coronary collateral (CC) vessel development helps protect against cardiovascular issues in patients with coronary chronic total occlusion (CTO), and its relationship with type 2 diabetes mellitus (T2DM) and diabetic microvascular complications (DMC) is not well understood.
  • * The study aimed to compare CC vessel presence and grading in T2DM patients with and without DMC during coronary angiography for chronic coronary syndrome (CCS).
  • * Results showed that patients with DMC had a significantly higher prevalence of CC and high-grade CC compared to those without DMC, suggesting that DMC is linked to enhanced CC development in T2DM patients with CTO.
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During pregnancy, the complex hormonal changes lead to a progressive decrease of insulin sensitivity that can drive the onset of gestational diabetes (GDM) or worsen an already-known condition of insulin resistance like type 2 diabetes, polycystic ovarian syndrome (PCOS), and obesity, with complications for the mother and the fetus. Metformin during pregnancy is proving to be safe in a growing number of studies, although it freely crosses the placenta, leading to a fetal level similar to maternal concentration. The aim of this literature review is to analyze the main available evidence on the use of metformin during, throughout, and beyond pregnancy, including fertilization, lactation, and medium-term effects on offspring.

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The on-chip integration of two-dimensional nanomaterials, having exceptional optical, electrical, and thermal properties, with terahertz (THz) quantum cascade lasers (QCLs) has recently led to wide spectral tuning, nonlinear high-harmonic generation, and pulse generation. Here, we transfer a large area (1 × 1 cm) multilayer graphene (MLG), to lithographically define a microthermometer, on the bottom contact of a single-plasmon THz QCL to monitor, in real-time, its local lattice temperature during operation. We exploit the temperature dependence of the MLG electrical resistance to measure the local heating of the QCL chip.

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Patched1 (PTCH1) is the principal tumour suppressor protein of the mammalian Hedgehog (HH) signalling pathway, implicated in embryogenesis and tissue homeostasis. PTCH1 inhibits the Class F G protein-coupled receptor Smoothened (SMO) via a debated mechanism involving modulating accessible cholesterol levels within ciliary membranes. Using extensive molecular dynamics (MD) simulations and free energy calculations to evaluate cholesterol transport through PTCH1, we find an energetic barrier of ~15-20 kJ mol for cholesterol export.

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Article Synopsis
  • Researchers developed a new spectroscopy system that uses electrically-pumped terahertz frequency-combs, enabling simultaneous monitoring and manipulation of emitted light phases without external signals.
  • The system relies on THz quantum cascade lasers and back-scattering techniques to exploit phase coherence, allowing control over the amplitude and frequency of terahertz signals in real-time.
  • This innovative approach provides a high-resolution nanoscope for mapping the terahertz responses of nanoscale materials, and it has potential applications across infrared imaging in various scientific fields, including plasmonics and quantum science.
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Mutations to genes that encode DNA-binding transcription factors (TFs) underlie a broad spectrum of human neurodevelopmental disorders. Here, we highlight the pathological mechanisms arising from mutations to TF genes that influence the development of mammalian cerebral cortex neurons. Drawing on recent findings for TF genes including ZBTB18, we discuss how functional missense mutations to such genes confer non-native gene regulatory actions in developing neurons, leading to cell-morphological defects, neuroanatomical abnormalities during foetal brain development and functional impairment.

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Engineering detection dynamics in nanoscale receivers that operate in the far infrared (frequencies in the range 0.1-10 THz) is a challenging task that, however, can open intriguing perspectives for targeted applications in quantum science, biomedicine, space science, tomography, security, process and quality control. Here, we exploited InAs nanowires (NWs) to engineer antenna-coupled THz photodetectors that operated as efficient bolometers or photo thermoelectric receivers at room temperature.

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Near-field microscopy discloses a peculiar potential to explore novel quantum state of matter at the nanoscale, providing an intriguing playground to investigate, locally, carrier dynamics or propagation of photoexcited modes as plasmons, phonons, plasmon-polaritons or phonon-polaritons. Here, we exploit a combination of hyperspectral time domain spectroscopy nano-imaging and detectorless scattering near-field optical microscopy, at multiple terahertz frequencies, to explore the rich physics of layered topological insulators as BiSe and BiTeSe, hyperbolic materials with topologically protected surface states. By mapping the near-field scattering signal from a set of thin flakes of BiSe and BiTeSe of various thicknesses, we shed light on the nature of the collective modes dominating their optical response in the 2-3 THz range.

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The scalable synthesis and transfer of large-area graphene underpins the development of nanoscale photonic devices ideal for new applications in a variety of fields, ranging from biotechnology, to wearable sensors for healthcare and motion detection, to quantum transport, communications, and metrology. We report room-temperature zero-bias thermoelectric photodetectors, based on single- and polycrystal graphene grown by chemical vapor deposition (CVD), tunable over the whole terahertz range (0.1-10 THz) by selecting the resonance of an on-chip patterned nanoantenna.

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A long-standing mystery in vertebrate Hedgehog signaling is how Patched 1 (PTCH1), the receptor for Hedgehog ligands, inhibits the activity of Smoothened, the protein that transmits the signal across the membrane. We previously proposed (Kinnebrew et al., 2019) that PTCH1 inhibits Smoothened by depleting accessible cholesterol from the ciliary membrane.

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Low-dimensional nanosystems are promising candidates for manipulating, controlling, and capturing photons with large sensitivities and low noise. If quantum engineered to tailor the energy of the localized electrons across the desired frequency range, they can allow devising of efficient quantum sensors across any frequency domain. Here, we exploit the rich few-electron physics to develop millimeter-wave nanodetectors employing as a sensing element an InAs/InAsP quantum-dot nanowire, embedded in a single-electron transistor.

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Article Synopsis
  • - Semiconductor nanowire field-effect transistors are seen as potential room-temperature terahertz frequency light detectors due to their effective low noise and high responsivity characteristics.
  • - Achieving a high sensitivity and fast response in terahertz photodetectors requires a deeper understanding of how they react to light, which conventional methods struggle to clarify.
  • - The study introduces a novel technique using high spatial resolution THz photocurrent nanoscopy to identify the mechanisms behind the photo-response in individual InAs nanowires, revealing significant photo-thermoelectric and bolometric currents and offering insights for design optimization.
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Background: A high level of glycosylated haemoglobin (HbA1c), which is a nonenzymatic glycosylation product, is correlated with an increased risk of developing microangiopathic complications in Diabetes Mellitus (DM). Erythrocyte membrane fluidity could provide a complementary index to monitor the development of complications since it is influenced by several hyperglycaemia-induced pathways and other independent risk factors.

Materials And Methods: 15 healthy controls and 33 patients with long-duration (≥20 years) type 1 Diabetes Mellitus (T1DM) were recruited.

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