How Reliable Is Fluorescence-Guided Surgery in Low-Grade Gliomas? A Systematic Review Concerning Different Fluorophores.

BACKGROUND: Fluorescence-guided surgery has been increasingly used to support glioma surgery with the purpose of obtaining a maximal safe resection, in particular in high-grade gliomas, while its role is less definitely assessed in low-grade gliomas. METHODS: A systematic review was conducted. 5-aminolevulinic acid, sodium fluorescein, indocyanine green and tozuleristide were taken into account. The main considered outcome was the fluorescence rate, defined as the number of patients in whom positive fluorescence was detected out of the total number of patients. Only low-grade gliomas were considered, and data were grouped according to single fluorophores. RESULTS: 16 papers about 5-aminolevulinic acid, 4 about sodium fluorescein, 2 about indocyanine green and 1 about tozuleristide were included in the systematic review. Regarding 5-aminolevulinic acid, a total of 467 low-grade glioma patients were included, and fluorescence positivity was detected in 34 out of 451 Grade II tumors (7.3%); while in Grade I tumors, fluorescence positivity was detected in 9 out of 16 cases. In 16 sodium fluorescein patients, seven positive fluorescent cases were detected. As far as indocyanine is concerned, two studies accounting for six patients (three positive) were included, while for tozuleristide, a single clinical trial with eight patients (two positive) was retrieved. CONCLUSIONS: The current evidence does not support the routine use of 5-aminolevulinic acid or sodium fluorescein with a standard operating microscope because of the low fluorescence rates. New molecules, including tozuleristide, and new techniques for fluorescence detection have shown promising results; however, their use still needs to be clinically validated on a large scale.

Infiltrative Type I Collagen in the Treatment of Morton's Neuroma: A Mini-Series.

Morton's neuroma (MN) is a compressive neuropathy of the common plantar digital nerve, most commonly affecting the third inter-digital space. The conservative approach is the first recommended treatment option. However, other different approaches have been proposed, offering several options of treatments, where, several degrees of efficacy and safety have been reported. We treated five consecutive patients affected by MN through three indirect ultrasound-guided injections of type I porcine collagen at weekly intervals. All patients were assessed before the treatment, after the treatment and up to 6 months after the last injection via AOFAS and VNS scores for pain, in which the function and pain were evaluated, respectively. In all patients, both analyzed variables progressively ameliorated, with benefits lasting until the last follow-up. The trend of the scores during the follow-up showed significant statistical differences. No side effects occurred. To our knowledge, this is the first study on injections of type I porcine collagen for the treatment of Morton's neuroma. Future research is needed to confirm the positive trend achieved in this MN mini-series.

Radiofrequency Ablation in Vertebral Body Metastasis with and without Percutaneous Cement Augmentation: A Systematic Review Addressing the Need for SPINE Stability Evaluation.

Vertebral body metastases (VBM) are one of the most frequent sites of bone metastasis, and their adequate therapeutic management still represents an insidious challenge for both oncologists and surgeons. A possible alternative treatment for VBM is radiofrequency ablation (RFA), a percutaneous technique in which an alternating current is delivered to the tumor lesion producing local heating and consequent necrosis. However, RFA alone could alter the biomechanics and microanatomy of the vertebral body, thus increasing the risk of post-procedure vertebral fractures and spine instability, and indeed the aim of the present study is to investigate the effects of RFA on spine stability. A systematic review according to PRISMA-P guidelines was performed, and 17 papers were selected for the systematic review. The results show how RFA is an effective, safe, and feasible alternative to conventional radiotherapy for the treatment of VBM without indication for surgery, but spine stability is a major issue in this context. Although exerting undeniable benefits on pain control and local tumor recurrence, RFA alone increases the risk of spine instability and consequent vertebral body fractures and collapses. Concomitant safe and feasible therapeutic strategies such as percutaneous vertebroplasty and kyphoplasty have shown synergic positive effects on back pain and improvement in spine stability.

Case Report: Postacute Rehabilitation of Guillain-Barré Syndrome and Cerebral Vasculitis-Like Pattern Accompanied by SARS-CoV-2 Infection.

Introduction: The main clinical manifestation of the novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is respiratory issues. Neurological manifestations are being increasingly recognized, including febrile seizures, headache, dizziness, and myalgia, as well as encephalopathy, encephalitis, stroke, and acute peripheral nerve diseases. Cerebral vasculitis is rarely reported. We describe a case of SARS-CoV-2 interstitial pneumonia complicated by flaccid tetraplegia due to Guillain-Barré Syndrome (GBS) associated with a cerebral vasculitis-like pattern. Case description: A 62-year-old man was hospitalized for cough, fever, and severe respiratory failure requiring tracheal intubation and invasive ventilation. The chest Computerized Tomography (CT) showed images related to interstitial pneumonia and the subsequent nasopharyngeal swab confirmed the presence of SARS-CoV-2 infection. During the hospitalization, there was a progressive deterioration of the senses associated with areflexic flaccid tetraplegia. The treatment with high doses of immunoglobulin G (IgG) led to the immediate improvement of the general conditions and a partial response in terms of recovery of the upper limb and of the distal lower limb movements. Subsequently the patient was admitted to our Rehabilitation Unit, where he received an intensive rehabilitation treatment consisting of physiotherapy and occupational therapy. Two months later the patient was discharged at home and able to walk independently even for long distances thanks to the use of Ankle-Foot Orthosis (AFO). Conclusion: In this report, we present the case of a patient with peripheral and central neurological damage occurred later severe pneumonia induced by SARS-CoV-2. The Immunoglobulin G therapy allowed the patient to benefit considerably from early rehabilitation, reaching the walking, increasing the independence in daily living tasks, and enabling safe discharge from hospital to home. Related neurologic complications of SARS-CoV-2 infection suffer a lack of understanding and further investigations should be conducted.

Temperature Driven Phase Transition at the Antimonene/Bi2Se3 van der Waals Heterostructure.

We report the discovery of a temperature-induced phase transition between the α and ß structures of antimonene. When antimony is deposited at room temperature on bismuth selenide, it forms domains of α-antimonene having different orientations with respect to the substrate. During a mild annealing, the ß phase grows and prevails over the α phase, eventually forming a single domain that perfectly matches the surface lattice structure of bismuth selenide. First-principles thermodynamics calculations of this van der Waals heterostructure explain the different temperature-dependent stability of the two phases and reveal a minimum energy transition path. Although the formation energies of freestanding α- and ß-antimonene only slightly differ, the ß phase is ultimately favored in the annealed heterostructure due to an increased interaction with the substrate mediated by the perfect lattice match.

Unexpected Rotamerism at the Origin of a Chessboard Supramolecular Assembly of Ruthenium Phthalocyanine.

We have investigated the formation and the properties of ultrathin films of ruthenium phthalocyanine (RuPc)2 vacuum deposited on graphite by scanning tunneling microscopy and synchrotron photoemission spectroscopy measurements, interpreted in close conjunction with ab initio simulations. Thanks to its unique dimeric structure connected by a direct Ru-Ru bond, (RuPc)2 can be found in two stable rotameric forms separated by a low-energy barrier. Such isomerism leads to a peculiar organization of the molecules in flat, horizontal layers on the graphite surface, characterized by a chessboard-like alternation of the two rotamers. Moreover, the molecules are vertically connected to form π-stacked columnar pillars of akin rotamers, compatible with the high conductivity measured in (RuPc)2 powders. Such features yield an unprecedented supramolecular assembly of phthalocyanine films, which could open interesting perspectives toward the realization of new architectures of organic electronic devices.

Self-Assembly of Graphene Nanoblisters Sealed to a Bare Metal Surface.

The possibility to intercalate noble gas atoms below epitaxial graphene monolayers coupled with the instability at high temperature of graphene on the surface of certain metals has been exploited to produce Ar-filled graphene nanosized blisters evenly distributed on the bare Ni(111) surface. We have followed in real time the self-assembling of the nanoblisters during the thermal annealing of the Gr/Ni(111) interface loaded with Ar and characterized their morphology and structure at the atomic scale. The nanoblisters contain Ar aggregates compressed at high pressure arranged below the graphene monolayer skin that is decoupled from the Ni substrate and sealed only at the periphery through stable C-Ni bonds. Their in-plane truncated triangular shapes are driven by the crystallographic directions of the Ni surface. The nonuniform strain revealed along the blister profile is explained by the inhomogeneous expansion of the flexible graphene lattice that adjusts to envelop the Ar atom stacks.

Silicon Reactivity at the Ag(111) Surface.

The modelization of silicene on Ag(111) is generally based on the assumption of a complete immiscibility between silicon and silver. However, there are recent reports that growth occurs inside the first layer of the Ag(111) terraces rather than on top of them. Here, we report on a combined density functional theory and scanning tunneling microscopy study unveiling the basic exchange mechanism between Si and the topmost layer Ag atoms and modeling the nucleation process. Our findings demonstrate that a strong Si-Ag interaction must be considered to properly describe the Si/Ag(111) interface.

Mn-silicide nanostructures aligned on massively parallel silicon nano-ribbons.

The growth of Mn nanostructures on a 1D grating of silicon nano-ribbons is investigated at atomic scale by means of scanning tunneling microscopy, low energy electron diffraction and core level photoelectron spectroscopy. The grating of silicon nano-ribbons represents an atomic scale template that can be used in a surface-driven route to control the combination of Si with Mn in the development of novel materials for spintronics devices. The Mn atoms show a preferential adsorption site on silicon atoms, forming one-dimensional nanostructures. They are parallel oriented with respect to the surface Si array, which probably predetermines the diffusion pathways of the Mn atoms during the process of nanostructure formation.

Detecting and localizing surface dynamics with STM: a study of the Sn/Ge(111) and Sn/Si(111) α-phase surfaces.

After almost three decades since the invention of the scanning tunnelling microscope (STM) its application to the study of dynamic processes at surfaces is attracting a great deal of interest due to its unique capacity to observe such processes at the atomic level. The α-phase of group IV adatoms on Ge(111) and Si(111) is the ideal playground for the analysis of critical phenomena and represents a prototype of a two-dimensional electron system exhibiting thermally activated peculiar Sn adatom dynamics. This paper will relate the study of adatom dynamics at the α-Sn/Ge(111) and α-Sn/Si(111) surfaces, discussing in detail the methods we used for such kinds of time-resolved measurements. The microscope tip was used to record the tunnelling current on top of an oscillating Sn adatom, keeping the feedback loop turned off. The dynamics of the adatoms is detected as telegraph noise present in the tunnelling versus time curves. With this method it is possible to increase the acquisition rate to the actual limit of the instrument electronics, excluding piezo movement and feedback circuitry response time. We put emphasis on the statistical data analysis which allows the localization of the sample areas that are involved in dynamical processes.

Metallic nature of the alpha-Sn/Ge(111) surface down to 2.5 K.

Low temperature (down to 2.5 K) scanning tunneling microscopy (STM) and spectroscopy (STS) measurements are presented to assess the nature of the alpha-Sn/Ge(111) surface. Bias-dependent STM and STS measurements have been used to demonstrate that such a surface preserves a metallic 3 x 3 reconstruction at very low temperature. A tip-surface interaction mechanism becomes active below about 20 K at the alpha-Sn/Ge(111) surface, resulting in an apparent unbuckled (sqrt[3] x sqrt[3]) reconstruction when filled states STM images are acquired with tunneling currents higher than 0.2 nA.

Airway inflammation and lung function decline in childhood post-infectious bronchiolitis obliterans.

Post-infectious bronchiolitis obliterans (PBO) is a rare form of chronic obstructive lung disease in children with few data on the pulmonary function outcome and underlying inflammatory process. The aim of this study was to determine the change in lung function over time and to investigate by bronchoalveolar lavage (BAL) the inflammatory characteristics of pulmonary involvement. Eleven Caucasian children with PBO were evaluated to estimate the average rate of change in lung function indices using a mixed model. The differential cytology and lymphocyte subsets of BAL fluid were analyzed. The median follow-up was 10.2 (IQR 3.2-12) years. The estimated forced expiratory volume in 1 sec (FEV1) had a baseline intercept of 57% predicted (62% predicted after bronchodilator) at 10 years of age which fell at a rate of 1.01% per year whereas the estimated forced expiratory flow 25-75 (FEF25-75) had a baseline intercept of 36% predicted (42% predicted after bronchodilator) at 10 years of age which fell at a rate of 1.04% per year. The estimated FEV1/FVC ratio had a baseline intercept of 70% (74% after bronchodilator) at 10 years of age which declined with an average slope of 1.02% per year (-1.10% per year after bronchodilator). Although the baseline and post-bronchodilator level of estimated FVC was abnormal (68% and 69% predicted, respectively) it did not change significantly with time. The median disease duration at BAL evaluation was 3.7 (IQR 0.7-8) years. The percentage differential cell counts were characterized by a significant increase in neutrophils (median 50%, IQR 1-66%), and a slight increase of lymphocytes (median 14%, IQR 7.5-15%). In conclusion, pulmonary function in childhood PBO is characterized by significant airway obstruction which deteriorates over time. The presence of an ongoing inflammatory process could explain the decline in lung function over time.

Evidence of Sn adatoms quantum tunneling at the alpha-Sn/Si(111) surface.

We present a low-temperature scanning tunneling microscopy study of the alpha-Sn/Si(111) surface that demonstrates the fluctuating behavior of the Sn adatoms. The dynamical fluctuation model, successfully applied in describing the alpha-Sn/Ge(111) surface, is proposed for the related alpha-Sn/Si(111) surface too, although with a much lower transition temperature. In addition, a new phenomenon appears responsible for the unexpected evidence that the average oscillation frequency remains constant at temperatures lower than 15 K, in contradiction to the Arrhenius law. We explain this phenomenon as quantum tunneling of Sn adatoms.

Direct observation of sn adatoms dynamical fluctuations at the Sn/Ge(111) surface.

The well-known low-temperature phase transition sqrt[3]xsqrt[3] to 3x3 for the 1/3 monolayer of Sn adatoms on the Ge(111) surface has been studied by scanning tunneling microscopy. The STM tip was used as a probe to record the tunneling current as a function of time on top of the Sn adatoms. The presence of steps on the current-time curves allowed the detection of fluctuating Sn atoms along the direction vertical to the substrate. We discuss the effect of temperature and surface defects on the frequency of the motion, finding consistency with the dynamical fluctuations model.

Polyamino acids as synthetic enzymes: mechanism, applications and relevance to prebiotic catalysis.

Polyamino acids, such as polyleucine, behave as synthetic enzymes in the asymmetric epoxidation of chalcone and other electron-deficient alkenes (the Julià-Colonna reaction). The influences of reaction conditions, of the molecular structure of the catalysts and of the scaling-up of the process on the enantioselectivity of the reaction have been determined. The kinetics and mechanism have been investigated using a soluble PEG-polyleucine conjugate, which behaves in a similar way to an enzyme, showing saturation kinetics for both chalcone and HOO-. Enantioselective catalysis is achieved with peptides with as few as five residues and scalemic catalysts show high chiral amplification. Here, we discuss the relevance of these-enzyme like catalysts to prebiotic processes, such as the role of small peptides in the formation of optically active cyanohydrins.

Mott phase at the surface of 1T-TaSe2 observed by scanning tunneling microscopy.

In this Letter we report the observation, by scanning tunneling microscopy, of a Mott metal to insulator transition at the surface of 1T-TaSe2. Our spectroscopic data compare considerably well with previous angle-resolved photoemission spectroscopy measurements and confirm the presence of a large hysteresis related to a first order process. The local character of the tunneling spectroscopy technique allows a direct visualization of the surface symmetry and provides spectroscopic measurements on the defect-free region of the sample. It follows that the electronic localization is driven purely by the enhancement of the charge density wave amplitude which drives a bandwidth controlled metal-insulator transition.

Kinetics of chalcone oxidation by peroxide anion catalysed by poly-l-leucine.

An insight into the kinetics, mechanism and optimum reaction conditions of the Julia-Colonna epoxidation has been gained using a soluble polyleucine catalyst.