Pure Dephasing of Light-Matter Systems in the Ultrastrong and Deep-Strong Coupling Regimes.

Pure dephasing originates from the nondissipative information exchange between quantum systems and environments, and plays a key role in both spectroscopy and quantum information technology. Often pure dephasing constitutes the main mechanism of decay of quantum correlations. Here we investigate how pure dephasing of one of the components of a hybrid quantum system affects the dephasing rate of the system transitions. We find that, in turn, the interaction, in the case of a light-matter system, can significantly affect the form of the stochastic perturbation describing the dephasing of a subsystem, depending on the adopted gauge. Neglecting this issue can lead to wrong and unphysical results when the interaction becomes comparable to the bare resonance frequencies of subsystems, which correspond to the ultrastrong and deep-strong coupling regimes. We present results for two prototypical models of cavity quantun electrodynamics: the quantum Rabi and the Hopfield model.

The Photonic Atom Probe as a Tool for the Analysis of the Effect of Defects on the Luminescence of Nitride Quantum Structures.

By collecting simultaneously optical and chemical/morphological data from nanoscale volumes, the Photonic Atom Probe (PAP) can be applied not only to the study of the relationship between optical and structural properties of quantum emitter but also to evaluate the influence of other factors, such as the presence of point defects, on the photoluminescence. Through the analysis of multiple layers of InGaN/GaN quantum dots (QDs), grown so that the density of structural defects is higher with increasing distance from the substrate, we establish that the light emission is higher in the regions exhibiting a higher presence of structural defects. While the presence of intrinsic point defects with non-radiative recombination properties remains elusive, our result is consistent with the fact that QD layers closer to the substrate behave as traps for non-radiative point defects. This result demonstrates the potential of the PAP as a technique for the study of the optical properties of defects in semiconductors.

Histology for nephrology, from pre-implantation to post-transplant kidney biopsy. Lesson learned from ReBIrth (Renal BIopsy for Kidney Transplantation Therapy).

A meeting entitled Renal BIopsy for Kidney Transplantation Therapy (ReBIrth) took place on May 31st, 2022 in Bologna, Italy. The meeting drew together nephrologists, surgeons, and pathologists and recognized as experts in the field of kidney transplantation in Italy. In this paper, we present our experience working with kidney transplants in the current era of immunosuppression therapy. The primary aim is to report the histopathological characteristics of failed kidney allografts after a consensus of experts reviewed the cases on a wholeslide imaging digital platform. Regardless of the cases discussed, digital pathology was reliable in identifying all the morphological and immunohistochemical features required to improve the correct use of immunosuppressive therapy to prevent graft failure and optimize patient management.

Behavior of the ε-Ga2O3:Sn Evaporation During Laser-Assisted Atom Probe Tomography.

The measurement of the composition of ε-Ga2O3 and the quantification of Sn doping in ε-Ga2O3:Sn by laser-assisted atom probe tomography (APT) may be inaccurate depending on the experimental conditions. Both the role of the laser energy and surface electric field were investigated, and the results clearly indicate that deviations from stoichiometry are observed changing the electric field conditions during APT. The measured atomic fraction of Ga can change from 0.45 at low field to 0.38 at high field, to be compared with the expected 0.4. This was interpreted in terms of preferential evaporation of Ga at high field and deficit of O at low field, which was caused by the formation of neutrals. The quantification of Sn-doping is accurate at low-field conditions, with an overestimation of the detected Sn-metallic fraction at high field. This suggests that Sn has a higher evaporation field compared to Ga. Finally, multiple detection events were in-depth studied, revealing that three dissociation reactions occur during APT: GaO2+ → Ga+ + O+; Ga2O22+ → Ga+ + GaO2+; Ga3O22+ → Ga+ + Ga2O2+. Nevertheless, only 2% of the detected events are related to such dissociation reactions, too small a fraction to fully explain the observed deviation from the stoichiometric composition in ε-Ga2O3.

Super-resolution Optical Spectroscopy of Nanoscale Emitters within a Photonic Atom Probe.

Atom Probe Tomography (APT) is a microscopy technique allowing for the 3D reconstruction of the chemical composition of a nanoscale needle-shaped sample with a precision close to the atomic scale. The photonic atom probe (PAP) is an evolution of APT featuring in situ and operando detection of the photoluminescence signal. The optical signatures of the light-emitting centers can be correlated with the structural and chemical information obtained by the analysis of the evaporated ions. It becomes thus possible to discriminate and interpret the spectral signatures of different light emitters as close as 20 nm, well beyond the resolution limit set by the exciting laser wavelength. This technique opens up new perspectives for the study of the physics of low dimensional systems, defects and optoelectronic devices.

Correlative investigation of Mg doping in GaN layers grown at different temperatures by atom probe tomography and off-axis electron holography.

Correlation between off-axis electron holography and atom probe tomography (APT) provides morphological, chemical and electrical information about Mg doping (p-type) in gallium nitride (GaN) layers that have been grown at different temperatures at a nanometric scale. APT allows access to the three-dimensional distribution of atoms and their chemical nature. In particular, this technique allows visualisation of the Mg-rich clusters observed in p-doped GaN layers grown by metal-organic chemical vapour deposition. As the layer growth temperature increases, the cluster density decreases but their size indicted by the number of atoms increases. Moreover, APT reveals that threading dislocations are decorated with Mg atoms. Off-axis electron holography provides complementary information about the electrical activity of the Mg doping. As only a small fraction of dopant atoms are ionised at room temperature, this fraction is increased by annealing the specimen to 400 °C in situ in a transmission electron microscope (TEM). A strong reduction of the dopant electrical activity is observed for increases in the layer growth temperature. The correlation of APT with TEM-based techniques was shown to be a unique approach in order to investigate how the growth temperature affects both the chemical distribution and electrical activity of Mg dopant atoms.

Current evidence on vitamin D deficiency and kidney transplant: What's new?

Kidney transplant is the treatment of choice for end-stage chronic kidney disease. Kidneys generate 1,25-dihydroxyvitamin D (calcitriol) from 25-hydroxyvitamin D (calcidiol) for circulation in the blood to regulate calcium levels. Transplant patients with low calcidiol levels have an increased risk of metabolic and endocrine problems, cardiovascular disease, type 2 diabetes mellitus, poor graft survival, bone disorders, cancer, and mortality rate. The recommended calcidiol level after transplant is at least 30 ng/mL (75 nmol/L), which could require 1000-3000 IU/d vitamin D3 to achieve. Vitamin D3 supplementation studies have found improved endothelial function and acute rejection episodes. However, since kidney function may still be impaired, raising calcidiol levels may not lead to normal calcitriol levels. Thus, supplementation with calcitriol or an analog, alfacalcidiol, is often employed. Some beneficial effects found include possible improved bone health and reduced risk of chronic allograft nephropathy and cancer.

Field-Dependent Measurement of GaAs Composition by Atom Probe Tomography.

The composition of GaAs measured by laser-assisted atom probe tomography may be inaccurate depending on the experimental conditions. In this work, we assess the role of the DC field and the impinging laser energy on such compositional bias. The DC field is found to have a major influence, while the laser energy has a weaker one within the range of parameters explored. The atomic fraction of Ga may vary from 0.55 at low-field conditions to 0.35 at high field. These results have been interpreted in terms of preferential evaporation of Ga at high field. The deficit of As is most likely explained by the formation of neutral As complexes either by direct ejection from the tip surface or upon the dissociation of large clusters. The study of multiple detection events supports this interpretation.

Sphingomonas paucimobilis osteomyelitis in an immunocompetent patient. A rare case report and literature review.

Sphingomonas paucimobilis occurs widely both in natural and nosocomial environments, including hospital water systems, respiratory therapy equipment, and laboratory instruments. It is an opportunistic pathogen that rarely causes infections in humans. Among S. paucimobilis nosocomial infections, osteomyelitis is particularly rare. Almost all infections occur in patients with comorbidities such as malignancy, immunosuppressant therapy, diabetes mellitus and acquired immunodeficiency syndrome. We present the first case of Sphingomonas paucimobilis osteomyelitis in an immunocompetent patient and include updated literature concerning infections by this microorganism.

Solubility Limit of Ge Dopants in AlGaN: A Chemical and Microstructural Investigation Down to the Nanoscale.

Attaining low-resistivity AlxGa1-xN layers is one keystone to improve the efficiency of light-emitting devices in the ultraviolet spectral range. Here, we present a microstructural analysis of AlxGa1-xN/Ge samples with 0 ≤ x ≤ 1, and a nominal doping level in the range of 1020 cm-3, together with the measurement of Ge concentration and its spatial distribution down to the nanometer scale. AlxGa1-xN/Ge samples with x ≤ 0.2 do not present any sign of inhomogeneity. However, samples with x > 0.4 display µm-size Ge crystallites at the surface. Ge segregation is not restricted to the surface: Ge-rich regions with a size of tens of nanometers are observed inside the AlxGa1-xN/Ge layers, generally associated with Ga-rich regions around structural defects. With these local exceptions, the AlxGa1-xN/Ge matrix presents a homogeneous Ge composition which can be significantly lower than the nominal doping level. Precise measurements of Ge in the matrix provide a view of the solubility diagram of Ge in AlxGa1-xN as a function of the Al mole fraction. The solubility of Ge in AlN is extremely low. Between AlN and GaN, the solubility increases linearly with the Ga mole fraction in the ternary alloy, which suggests that the Ge incorporation takes place by substitution of Ga atoms only. The maximum percentage of Ga sites occupied by Ge saturates around 1%. The solubility issues and Ge segregation phenomena at different length scales likely play a role in the efficiency of Ge as an n-type AlGaN dopant, even at Al concentrations where Ge DX centers are not expected to manifest. Therefore, this information can have direct impact on the performance of Ge-doped AlGaN light-emitting diodes, particularly in the spectral range for disinfection (≈260 nm), which requires heavily doped alloys with a high Al mole fraction.

Prolonged Delayed Graft Function Due to an Extensive Renal Graft Subcapsular Hematoma: Is Conservative Management Justified?

A 62-year-old male patient with diabetes underwent deceased-donor kidney transplant at our transplant unit. At reperfusion, a small and clinically not significant subcapsular hematoma was noted. The patient's postoperative course was characterized by delayed graft function since the beginning but was further complicated on postoperative day 6 by evidence (shown at daily Doppler ultrasonography) of a wide increase of the hematoma. The hematoma, which was just visible before, was now leading to graft compression because it covered up to two-thirds of the cortical surface. The patient showed no hemo-dynamic instability and showed no significant drop in hemoglobin values. Capsulotomy was not performed because it was deemed too risky. The patient was given strict follow-up with Doppler ultrasonography and high-resolution imaging techniques (magnetic resonance imaging and computed tomography scan). In the following days, spontaneous resolution of the hematoma and progressive improvement of Doppler findings were observed, which preceded full recovery of graft function. Conservative management, in hemodynamically stable patients, seems to be a valid approach of this condition. By avoiding surgery or other interventional procedures, a conservative approach allows reduced risk of further complications. Strict monitoring with Doppler ultrasonography is a valid tool for follow-up, along with high-resolution imaging techniques such as magnetic resonance imaging and computed tomography to confirm diagnosis.

Diagnostic and therapeutic appropriateness in bone and joint infections: results of a national survey.

The impact of infectious diseases (ID) specialist consultation in the management of many types of bacterial infections has been fully demonstrated but not for bone and joint infections (BJIs). Nineteen ID Italian centres collected of data from June 2009 to May 2012. Italian guidelines (2009) were used to determine the appropriateness of the diagnostic and therapeutic process of BJIs before and after consulting an ID specialist. Data on 311 patients were collected: 111 cases of prosthetic joint infection, 99 osteomyelitis, 64 spondylodiscitis and 37 fixation device infection. A significant increase of microbiological investigations, imaging techniques and blood inflammation markers were noted after consulting the ID specialist. Moreover, inappropriateness of treatment duration, dosage, and number of administrations significantly decreased after consultation. Infectious disease specialist intervention in the management of BJIs significantly increases the appropriateness both in performing instrumental and laboratory analysis, but especially in determining the correct therapy.

Epidemiology and antibiotic resistance in a large Italian teaching hospital.

We focused our attention on susceptibility profile of Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. isolated from biological specimens at the University Hospital of Salerno between June 2011 and October 2012. Acinetobacter, with a prevalence of Acinetobacter baumannii (97%) presented a high range of resistance to the antimicrobials considered, excluding colistin (COL). Klebsiella spp. isolates, with a prevalence of Klebsiella pneumoniae (90%), presented a variable pattern of resistance [from 9·8% for COL to 50% for levofloxacin (LEV)]. Extended-spectrum beta-lactamases production was detected in 15% of isolates. Most Pseudomonas isolates were P. aeruginosa with a high rate of resistance (95% to amoxicillin/clavulanate and trimethoprim/sulfamethoxazole, and <50% to the other antibiotics). Colistin remained the most effective drug tested. This study provided useful information of the local bacterial epidemiology hopefully permitting to establish a more effective empirical therapy, preventing the inappropriate use of antibacterial agents and possibly limiting the diffusion of antibacterial resistance.

[Management of diabetic foot infections]. / Management del piede diabetico infetto.

All infected diabetic foot wounds require antibiotic treatment. Antibiotic treatment is influenced by the patient's features as the vascular status, the leukocyte function and the kidney activity. The initial antibiotic regimen is usually chosen empirically and it can be modified on the basis of the microbiological information obtained subsequently. The initial empiric therapy should be based, on one hand, on the grade of infected lesion and, secondly, on the epidemiological data. Almost all of the mild/moderate infected wounds can be treated with antibiotics with a spectrum of activity limited to Gram-positive cocci. Treatment with oral antibiotics is sufficient in most cases in patients with mild/moderate infections. With severe infections is more appropriate to use a broad-spectrum antibiotic therapy. Furthermore it is safer to start a parenteral therapy, possibly modifying it into an oral administration if the patient has stabilized. The most frequently pathogen observed in diabetic foot infections is Staphylococcus aureus. It is important to understand whether there are elements that may lead to the suspicion of MRSA infection in order to establish an appropriate antimicrobial therapy.

[Diabetic foot: definitions]. / Il piede diabetico: definizioni.

Diabetes is a metabolic disorder characterized by chronic hyperglycemia associated with impaired glucose, lipid and protein metabolism. The purpose of our work is to provide a clear and precise definition of the disease and of his frequent complications: diabetic foot and diabetic foot infection.