Determinants of prolonged viral RNA shedding in hospitalized patients with SARS-CoV-2 infection

OBJECTIVE

To evaluate determinants of prolonged viral RNA shedding in hospitalized patients with SARS-CoV-2 infection.

MATERIALS AND METHODS

Hospitalized patients with SARS-CoV-2 positive nasopharyngeal RT-PCR were included in a single-center, retrospective study. Patients were divided in 2 groups according to the timing of viral clearance [≤14 days, "early clearance (EC)" and >14 days, "late clearance (LC)"].

RESULTS

179 patients were included in the study (101 EC, 78 LC), with median age 62 years. Median time of viral shedding was 14 days (EC/LC 10 and 19 days, respectively, P < 0.0001). Univariate analyses showed that age, male gender, receiving corticosteroids, receiving tocilizumab, ICU admission, low albumin and NLR ratio were associated with late viral clearance. In the multivariable analysis, older age (P = 0.016), albumin level (P = 0.048), corticosteroids (P = 0.021), and tocilizumab (P = 0.015) were significantly associated with late viral clearance.

CONCLUSIONS

Age, albumin, tocilizumab and corticosteroid treatment were independently associated with a prolonged SARS-CoV-2 RNA shedding.

Spectroscopic identification of the chemical interplay between defects and dopants in Al-doped ZnO

Contributions to the spectroscopic response of defects and dopants in Al-doped ZnO films are determined combining X-ray spectroscopies and DFT.

AFM-based tribological study of nanopatterned surfaces: the influence of contact area instabilities

Although the importance of morphology on the tribological properties of surfaces has long been proved, an exhaustive understanding of nanopatterning effects is still lacking due to the difficulty in both fabricating 'really nano-' structures and detecting their tribological properties. In the present work we show how the probe-surface contact area can be a critical parameter due to its remarkable local variability, making a correct interpretation of the data very difficult in the case of extremely small nanofeatures. Regular arrays of parallel 1D straight nanoprotrusions were fabricated by means of a low-dose focused ion beam, taking advantage of the amorphization-related swelling effect. The tribological properties of the patterns were detected in the presence of air and in vacuum (dry ambient) by atomic force microscopy. We have introduced a novel procedure and data analysis to reduce the uncertainties related to contact instabilities. The real time estimation of the radius of curvature of the contacting asperity enables us to study the dependence of the tribological properties of the patterns from their geometrical characteristics. The effect of the patterns on both adhesion and the coefficient of friction strongly depends on the contact area, which is linked to the local radius of curvature of the probe. However, a detectable hydrophobic character induced on the hydrophilic native SiO2 has been observed as well. The results suggest a scenario for capillary formation on the patterns.

Nanoscale frictional behavior of graphene on SiO₂ and Ni(111) substrates

Friction characteristics of graphene deposited on different substrates have been studied by atomic force microscopy (AFM). In particular, we compared mechanically exfoliated graphene transferred over Si/SiO₂ with respect to monolayer (ML) graphene grown in our laboratory by low temperature chemical vapor deposition on Ni(111) single crystal. Friction force measurements by AFM have been carried out as function of load under different environment conditions, namely vacuum (10(-5) Torr), nitrogen and air. The typical decrease of friction force with increasing number of layers has been observed on graphene over Si/SiO₂ in all environment including vacuum. Continuum mechanical approximation has been used to analyze the friction versus load curves of ML graphene on Ni(111). Analysis shows that Derjaguin-Mueller-Toporov model is in good agreement with our experimental data indicating that overall behavior of the interface graphene-Ni(111) is relatively rigid respect to out of plane deformations. This result is consistent with the structural characteristics of the interface since graphene grows in registry with Ni(111) surface with covalent bonding character. Finally, the shear strength and the work of adhesion of the two systems with respect to AFM tip in vacuum have been compared. The result of this procedure indicates that shear strength and work of adhesion measured on graphene-Si/SiO₂ interface are always greater than those on graphene-Ni(111) interface.

Structural and morphological modifications of thermally reduced cerium oxide ultrathin epitaxial films on Pt(111)

Thermal treatments under vacuum and oxygen induce reversible modifications in the stoichiometry, surface morphology and structure of epitaxial CeO₂ films.

Controlled co-deposition of FePt nanoparticles embedded in MgO: a detailed investigation of structure and electronic and magnetic properties

Films of FePt nanoparticles (NPs) embedded in MgO were obtained by controlled co-deposition of FePt NPs pre-formed by a gas aggregation source and of Mg evaporated in an oxygen atmosphere. Assemblies of core-shell FePt@MgO NPs and films of FePt NPs embedded in MgO matrix could be obtained by varying FePt and Mg deposition rates. Transmission electron microscopy (TEM) and high resolution-TEM revealed the core-shell structure of the NPs, with an FePt core (of average diameter (d) = 4.75 nm) presenting a multitwinned icosahedral structure, and MgO partially in crystalline form. The functional effect of the MgO shell in shielding the FePt core from external oxidation was shown with XPS. Upon controlled annealing, a transition from A1 to L10 ordering could be obtained, with structural and morphological re-arrangement. The magnetic hysteresis loops obtained from alternating gradient field magnetometry at room temperature show a 'wasp-waist' shape, with small values of coercive field (Hc = 300-1400 Oe), decreasing at increasing amounts of co-deposited MgO.

Ag surface diffusion and out-of-bulk segregation in CrN-Ag nano-composite coatings

CrN-Ag nanocomposite coatings are deposited on Si(100) wafers and 20MnCr5 steel disks in a mixed Ar+N2 atmosphere by reactive magnetron sputtering. Structure, composition and morphology were investigated by Scanning Electron Microscopy (SEM), Auger Electron Spectroscopy (AES), X-ray Photoemission Spectroscopy (XPS), X-ray Diffraction (XRD) and Focused Ion Beam (FIB) cross sectional analysis. The as deposited film matrix is mainly composed by CrN phase (78%), but a relevant part (28%) is composed by Cr2N. Ag agglomerates in the CrN matrix forming elongated grains 200-400 nm wide and 50-100 nm high, which extends on the top of CrN columns. At the surface Ag aggregates into two different structures: large tetrahedral crystalline clusters, with typical dimension ranging from 200 to 500 nm, and smaller Ag nanoparticles with diameter of 15-25 nm. The annealing in N2 atmosphere up to 500 degrees C does not affect size and distribution of the Ag grains in the sub-surface region, while it induces a size increase of the bigger Ag clusters on the surface, mainly related to Ag surface diffusion and clusters coalescence. Annealing at higher temperature leads to an evident Ag out-of-bulk segregation, generating Ag depleted voids in the near-surface region, and further increasing of the Ag clusters size at the surface. Tribological tests on as deposited CrN-Ag film reveal a coefficient of friction against a steel ball reduced with respect to CrN film, probably related to the presence of Ag which acts as solid lubricant, but the coating is removed after a very short sliding distance. The poor mechanical properties of the realized Ag-based coatings are confirmed by lower hardness and Young modulus values with respect to pure CrN.

Role of roughness parameters on the tribology of randomly nano-textured silicon surface

This experimental work is oriented to give a contribution to the knowledge of the relationship among surface roughness parameters and tribological properties of lubricated surfaces; it is well known that these surface properties are strictly related, but a complete comprehension of such correlations is still far to be reached. For this purpose, a mechanical polishing procedure was optimized in order to induce different, but well controlled, morphologies on Si(100) surfaces. The use of different abrasive papers and slurries enabled the formation of a wide spectrum of topographical irregularities (from the submicro- to the nano-scale) and a broad range of surface profiles. An AFM-based morphological and topographical campaign was carried out to characterize each silicon rough surface through a set of parameters. Samples were subsequently water lubricated and tribologically characterized through ball-on-disk tribometer measurements. Indeed, the wettability of each surface was investigated by measuring the water droplet contact angle, that revealed a hydrophilic character for all the surfaces, even if no clear correlation with roughness emerged. Nevertheless, this observation brings input to the purpose, as it allows to exclude that the differences in surface profile affect lubrication. So it is possible to link the dynamic friction coefficient of rough Si samples exclusively to the opportune set of surface roughness parameters that can exhaustively describe both height amplitude variations (Ra, Rdq) and profile periodicity (Rsk, Rku, Ic) that influence asperity-asperity interactions and hydrodynamic lift in different ways. For this main reason they cannot be treated separately, but with dependent approach through which it was possible to explain even counter intuitive results: the unexpected decreasing of friction coefficient with increasing Ra is justifiable by a more consistent increasing of kurtosis Rku.

Structure and stability of nickel/nickel oxide core-shell nanoparticles

The results of a combined x-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HR-TEM) study of Ni nanoparticles (NP), before and after oxidation, are presented. An experimental set-up was realized for the preparation and study of pre-formed NP films, concentrating the attention on Ni NP in the diameter range between 4 and 8 nm. The XPS data were taken in situ from NPs after different stages of oxidation, including controlled dosing of O(2) gas in the experimental system and exposure to the atmosphere. The Ni 2p structure is a combination of spectra from metallic Ni in the NP core and from the oxide shell. The signal from the NP core was observed even for samples after exposure to air. From the comparison of HR-TEM experimental images with theoretical simulations, it was found that the Ni NP core has a regular multitwinned icosahedral structure, composed of single-crystal tetrahedra with (111) faces. The NiO phase is clearly observed forming islands on the NP surface.

Structural And Compositional Modifications of III–V Ternary and Quaternary Compounds Induced by Ion Bombardment

The effect of low energy (0.5 to 5 keV) Ar+ beams on the surface structure and composition of monocrystalline ternary In0.53Ga0.47As and quaternary In0.70Ga0.30As0.64P0.36 films epitaxially grown by MO-VPE on InP (100) substrate has been investigated. Quantitative Auger electron spectroscopy has been used with the elemental standard method taking into account the electron diffraction effects. For both semiconductors, the outermost surface layer has been found to be Ga and In enriched. In the subsurface region, the Ga enrichment is even larger, at the expense of As and In. In the quaternary film, P is depleted in the surface as well in the subsurface region. Angular Resolved Auger Electron Spectroscopy is applied to the structural study of the sputter-etched surface. The nature and spatial extension of the ion-induced surface damage have been investigated at different energies, and doses of the primary ion beam. Is has been found that the resistance to the amorphization is strongly enhanced in InGaAs with respect to GaAs.

The analytical relations between particles and probe trajectories in atomic force microscope nanomanipulation

Analytical expressions relating the trajectories of spherical nanoparticles pushed by an atomic force microscope tip to the scan pattern of the tip are derived. In the case of a raster scan path, the particles are deflected in a direction defined by the geometries of tip and particles and the spacing b between consecutive scan lines. In the case of a zigzag scan path, the particles are deflected in a range of directions around 90 degrees, also depending on the parameter b. Experimental results on gold nanoparticles manipulated on silicon surfaces in ambient conditions confirm the predictions of our model.

Complementary use of local excision and transanal endoscopic microsurgery for rectal cancer after neoadjuvant chemoradiation

BACKGROUND

Neoadjuvant therapies have significantly improved local control and survival of patients with rectal cancer. Nevertheless, although a complete pathologic response can be achieved in 30% of cases, a transabdominal surgical resection is always required. This study aimed, for the first time, to test in the literature the feasibility of local excision combined with transanal endoscopic microsurgery (TEM) as a surgical option for patients treated with neoadjuvant chemoradiation.

METHODS

Between July 1997 and December 2002, 30 patients with rectal cancer affected by an extraperitoneal tumor entered a protocol consisting of neoadjuvant chemoradiation followed by surgery. The surgical treatment, consisting of open surgery, local excision, or TEM, was planned according to the patient's clinical response after chemoradiation and distance from the anal verge.

RESULTS

A significant clinical downstaging was observed in eight patients. Five of these patients underwent TEM, and three had local excision. Consequently, open surgery was performed for 22 patients. Histology showed six cases of complete pathologic response: three in the open surgery group and three in the transanal excision group. After a mean follow-up period of 47 months, the disease-free survival rate was 77% in the open surgery group and 100% in TEM or local excision group.

CONCLUSIONS

The findings suggest the complementary feasibility of TEM and local excision after neoadjuvant chemoradiation. However, randomized trials are needed to confirm the oncologic safety of this approach.

Iron oxidation, interfacial expansion, and buckling at the Fe/NiO(001) interface

In order to provide a structural basis for a physical understanding of exchange bias in metal/magnetic-oxide interfaces, we have determined the structure of the Fe/NiO(001) interface by means of x-ray absorption spectroscopy and ab initio density functional theory calculations. A Fe-Ni alloyed phase on top of an interfacial FeO planar layer is formed. The FeO layer exhibits a 7% expanded interlayer distance and a 0.3 A buckling; its presence is predicted to increase the spin magnetic moment of the interface Fe atoms by 0.6 mu(B), compared to the ideally abrupt interface.

Prognostic factors after surgery for locally recurrent rectal cancer: an overview

PURPOSE

Local recurrence of rectal cancer occurs in a considerable group of patients who have undergone radical treatment for primary tumour. The treatment of choice is surgical resection but the prognosis remains poor, as a negative margin excision is possible in only a small subset of patients. A review of prognostic factors for locally recurrent rectal cancer (LRRC) after surgery is presented.

METHODS

We systematically reviewed the literature for reports on prognostic factors after surgical excision of LRRC. These reports were identified through a review of the Medline database from 1982 to 2004.

RESULTS

This review highlights the most important prognostic factors for LRRC patients treated with surgery. Data are grouped on the basis of the prognostic factors investigated.

CONCLUSIONS

R0 resection seems to be the only reliable prognostic factor; however, symptoms, pre-operative CEA doubling time, performance status and pre-operative radiotherapy can help patient selection before surgery. The results of this review provide the basis for improved outcome, aiming to assess patients who would benefit from reoperation.

[Xanthogranulomatous pyelonephritis and renal carcinoma. Report of a clinical case and review of the literature]

Xanthogranulomatous pyelonephritis is a rare disease of the kidney; renal parenchyma is replaced by lesions radiologically simulating clear cell carcinoma. We present a case of a 62-year-old diabetic woman observed at our institution for the appearance of back pain and dysuria. A CT scan revealed a large lesion of left kidney with psoas muscle infiltration and the patient undrwent a nephrectomy. Histology surprisingly showed a xanthogranulomatous pyelonephritis. Though recent reports demonstrated the feasibility of conservative management of XGP with antibiotics, the use of pre-operative biopsy is still limited by the risk of seeding and the high false-negative results. How to distinguish xanthogranulomatous pyelonephritis from renal cancer?

[Signet-ring cell carcinoma of the Vater's ampulla: report of a clinical case]

We report the case of a sixty-six year-old man admitted at our hospital with a suspected malignant tumor of the ampulla of Vater. The patient underwent a Pylorus-preserving pancreatico-duodenectomy. Histology showed a signet-ring cell carcinoma of the ampulla of Vater. This case is the 13th report in the literature of a signet-ring cell carcinoma of the ampulla of Vater.

[Pancreatic tumor: unusual onset of Von-Hippel Lindau syndrome]

The Von-Hippel Lindau (VHL) disease is a rare genetically determined syndrome. Clinical course depends on the occurrence of multiple tumors as central nervous system tumors, phaeochromocytoma and renal cell carcinoma. We describe the second case in the literature reporting about a patient affected by a pancreatic neuroendocrine tumor as the first clinical sign of VHL disease. It has been showed that only a strict follow-up can effectively improve survival. Based on the present case, the follow-up of patients affected by VHL syndrome should routinely include functional tests and imaging exams of the pancreas.

Prognostic value of Bax, Bcl-2, p53, and TUNEL staining in patients with radically resected ampullary carcinoma

BACKGROUND

There is a lack of data in the literature concerning the identification of potential prognostic factors in ampullary adenocarcinoma.

AIMS

To examine the prognostic significance of Bax, Bcl-2, and p53 protein expression and the apoptotic index in a large cohort of uniformly treated patients with radically resected ampullary cancer.

METHODS

All patients with a pathological diagnosis of ampullary cancer and radical resection were evaluated. Expression analysis for p53, Bax, and Bcl-2 was performed by immunohistochemistry. Apoptotic cells were identified by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL).

RESULTS

Thirty nine tumour specimens from patients with radically resected ampullary adenocarcinoma were studied. A positive significant correlation between Bax and p53 expression was found by rank correlation matrix (p < 0.001). A trend towards a positive correlation was found between the apoptotic index and p53 expression (p = 0.059). By univariate analysis, overall survival was influenced by Bax expression, p53 expression, and TUNEL staining (p = 0.001, p = 0.01, and p = 0.03, respectively). Bcl-2 expression did not influence overall survival in these patients (p = 0.55). By multivariate Cox regression analysis, the only immunohistochemical parameter that influenced overall survival was Bax expression (p = 0.020).

CONCLUSIONS

These results provide evidence that apoptosis may be an important prognostic factor in patients with radically resected ampullary cancer. This study is the first to assess the clinical usefulness of Bax expression in radically resected ampullary cancer.

Magnetic dichroism and spin structure of antiferromagnetic NiO(001) films

We find that Ni L2 edge x-ray magnetic linear dichroism is fully reversed for NiO(001) films on materials with reversed lattice mismatch. We relate this phenomenon to a preferential stabilization of magnetic S domains with main spin component either in or out of the plane, via dipolar interactions. This suggests a way to selectively control spin structures in 3d systems with small spin-orbit coupling.

[Bilateral distal ureteral obstruction: unusual complication of appendicular abscess]

We describe the case of a 6-year-old boy who presented post-renal anuria and renal failure five days after appendectomy and drainage of a periappendicular abscess. Only mild dilatation of the urinary tract was observed on ultrasound and small calculi were documented at the ureterovesical junction bilaterally. Diuresis was restored by the insertion of uretercatheters. Awareness of this complication and immediate treatment can avoid permanent impairment of renal function.

Recurrent peptic stenosis of the esophagus: treatment with a self-expanding metallic stent

A 12-year-old neurologically impaired boy with recurrent peptic stenosis of the esophagus was treated successfully with use of a self-expanding metallic stent that remained for 3 months.

Jackson-Weiss syndrome: identification of two novel FGFR2 missense mutations shared with Crouzon and Pfeiffer craniosynostotic disorders

Jackson-Weiss syndrome is a rare skeletal disorder characterized by craniosynostosis associated with foot malformations. This condition is inherited as an autosomal dominant trait with complete penetrance and wide phenotypic heterogeneity. Mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have been recently identified as causes of this syndrome and of at least four other craniosynostotic disorders, namely the Apert, Beare-Stevenson cutis gyrata, Crouzon and Pfeiffer syndromes. We report two novel FGFR2 missense mutations associated with phenotypes consistent with Jackson-Weiss syndrome. Both nucleotide changes predict a serine for cysteine-342 substitution in the second half of the third immunoglobulin-like domain. The replacement of Cys342 with arginine has previously been reported in one of the three Jackson-Weiss cases investigated. Interestingly, both Cys342Ser and Cys342Arg substitutions have been found to be associated with the Crouzon and Pfeiffer phenotypes; a phenotypic heterogeneity, Crouzon vs Jackson-Weiss clinical features, has been also observed for Gln289Pro and Ala344Gly amino-acid changes. This finding indicates the genetic homogeneity of the "heterogeneous" Jackson-Weiss phenotype and a common molecular basis for these apparently "clinically distinct" craniosynostotic disorders.

Trp290Cys mutation in exon IIIa of the fibroblast growth factor receptor 2 (FGFR2) gene is associated with Pfeiffer syndrome

Pfeiffer syndrome is a skeletal disorder characterized by craniosynostosis associated with foot and hand anomalies. Mutations in the genes encoding fibroblast growth factor receptors 1 and 2 (FGFR1 and FGFR2) have recently been implicated in the aetiology of such a syndrome, as well as of other craniosynostotic conditions. We now report a novel missense mutation, a G to C transversion at position 1049 (exon IIIa) of FGFR2, detected in a patient with severe Pfeiffer clinical features. The mutation results in the substitution of a cysteine for tryptophan-290 in the third immunoglobulin-like domain and affects both spliceoforms of FGFR2. Mutations causing replacement of tryptophan-290 have also been reported previously in Crouzon syndrome, a similar but clinically distinct craniosynostotic disorder. This finding confirms the involvement of mutations of FGFR2 exon IIIa in Pfeiffer syndrome, and emphasizes both the extensive heterogeneity of the FGFR2 mutations that result in the Pfeiffer phenotype and the perturbations caused by unpaired cysteine residues in receptor dimerization and transduction of the FGFs signal.

B-myb transcriptional regulation and mRNA stability during differentiation of neuroblastoma cells

B-myb and c-myb expression is high in neuroblastoma cells and declines during retinoic acid-induced differentiation. We show here that B-myb down-regulation during retinoic acid-induced differentiation of LAN-5 neuroblastoma cells occurs at the transcriptional level. In addition, we measured B-myb and c-myb messenger RNA half-lives, and found that, unlike c-myb, B-myb messenger RNA was remarkably stable (> 10 h). Inhibition of protein synthesis by treatment with cycloheximide increased B-myb messenger RNA levels, suggesting that one or more labile proteins act as repressors of B-myb transcription. In the same cell line, blocking protein synthesis decreased the level of c-myb mRNA under both normal and differentiative conditions. Thus, B-myb and c-myb undergo similar transcriptional regulation, but there are specific differences in the stability of their messenger RNAs and in the mechanisms through which their transcription is controlled. These differences could reflect different functional roles played by c-myb and B-myb in neuroblastoma cells.

Treatment of claustrophobias and snake/spider phobias: fear of arousal and fear of context

Forty-nine individuals with fears of snakes or spiders, and 21 individuals with claustrophobic fear were assigned randomly to two sessions of either in vivo exposure plus relaxation or in vivo exposure plus disconfirmation of misappraisals of bodily sensations. Behavioral, subjective and physiological assessments were conducted pre and post treatment, and 4 weeks later. As hypothesized, disconfirmation of misappraisals of bodily sensations benefited claustrophobic fear reduction, but had little effect on fears of snakes or spiders. However, differential treatment effects failed to generalize to nontargetted phobic situations, or generalize over time. In addition, the two treatments affected basic beliefs about arousal sensations equally.