Accuracy of saliva for SARS-CoV-2 detection in outpatients and their household contacts during the circulation of the Omicron variant of concern.

BACKGROUND: While nasopharyngeal (NP) swabs are considered the gold standard for severe acute respiratory coronavirus 2 (SARS-CoV-2) real-time reverse transcriptase-polymerase chain reaction (RT-PCR) detection, several studies have shown that saliva is an alternative specimen for COVID-19 diagnosis and screening. METHODS: To analyze the utility of saliva for the diagnosis of COVID-19 during the circulation of the Omicron variant, participants were enrolled in an ongoing cohort designed to assess the natural history of SARS-CoV-2 infection in adults and children. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Cohen's kappa coefficient were calculated to assess diagnostic performance. RESULTS: Overall, 818 samples were collected from 365 outpatients from January 3 to February 2, 2022. The median age was 32.8 years (range: 3-94 years). RT-PCR for SARS-CoV-2 was confirmed in 97/121 symptomatic patients (80.2%) and 62/244 (25.4%) asymptomatic patients. Substantial agreement between saliva and combined nasopharyngeal/oropharyngeal samples was observed with a Cohen's kappa value of 0.74 [95% confidence interval (CI): 0.67-0.81]. Sensitivity was 77% (95% CI: 70.9-82.2), specificity 95% (95% CI: 91.9-97), PPV 89.8% (95% CI: 83.1-94.4), NPV 87.9% (95% CI: 83.6-91.5), and accuracy 88.5% (95% CI: 85.0-91.4). Sensitivity was higher among samples collected from symptomatic children aged three years and older and adolescents [84% (95% CI: 70.5-92)] with a Cohen's kappa value of 0.63 (95% CI: 0.35-0.91). CONCLUSIONS: Saliva is a reliable fluid for detecting SARS-CoV-2, especially in symptomatic children and adolescents during the circulation of the Omicron variant.

Modeling the Field Emission Enhancement Factor for Capped Carbon Nanotubes Using the Induced Electron Density.

In many field electron emission experiments on single-walled carbon nanotubes (SWCNTs), the SWCNT stands on one of two well-separated parallel plane plates, with a macroscopic field FM applied between them. For any given location "L" on the SWCNT surface, a field enhancement factor (FEF) is defined as FL/FM, where FL is a local field defined at "L". The best emission measurements from small-radii capped SWCNTs exhibit characteristic FEFs that are constant (i.e., independent of FM). This paper discusses how to retrieve this result in quantum-mechanical (as opposed to classical electrostatic) calculations. Density functional theory (DFT) is used to analyze the properties of two short, floating SWCNTs, capped at both ends, namely, a (6,6) and a (10,0) structure. Both have effectively the same height (∼5.46 nm) and radius (∼0.42 nm). It is found that apex values of local induced FEF are similar for the two SWCNTs, are independent of FM, and are similar to FEF values found from classical conductor models. It is suggested that these induced-FEF values are related to the SWCNT longitudinal system polarizabilities, which are presumed similar. The DFT calculations also generate "real", as opposed to "induced", potential-energy (PE) barriers for the two SWCNTs, for FM values from 3 V/µm to 2 V/nm. PE profiles along the SWCNT axis and along a parallel "observation line" through one of the topmost atoms are similar. At low macroscopic fields, the details of barrier shape differ for the two SWCNT types. Even for FM = 0, there are distinct PE structures present at the emitter apex (different for the two SWCNTs); this suggests the presence of structure-specific chemically induced charge transfers and related patch-field distributions.

Evaluation of recurrence and surgical complementation rates after endoscopic resection of large colorectal non-pedunculated lesions.

BACKGROUND AND AIM: the process that leads to the development of colorectal cancer takes many years and most tumors originate from polyps and non-polypoid lesions. Techniques of endoscopic resection are surgical treatment options, even in case of large lesions or with initial invasion. This study aimed to evaluate the recurrence and surgical complementation rates after endoscopic resection of large colorectal non-pedunculated lesions. METHODS: a retrospective, longitudinal and descriptive trial was performed via an analysis of colonoscopies with the resection of non-pedunculated lesions larger than 3 cm, performed between 2014 and 2017. RESULTS: sixty-two lesions were included from 61 patients and 32 (52.5 %) were female. The age ranged from 36 to 89 years, with a mean age of 60.5 years. Lesions had an average diameter of 40.08 mm, ranging from 30 to 80 mm. Regarding the location of the lesions, the most frequent colonic segments were the ascending and rectum, both accounting for 22.6 %. Considering the morphologic endoscopic classification, 67.7 % were granular laterally spreading tumors (LST), 38.8 % were homogeneous granular and 29 % were mixed granular. The most frequent histological types were tubulovillous adenoma (30.7 %) and intramucosal adenocarcinoma (29 %). The resection technique was piecemeal mucosectomy in 85.5 %. Five lesions were removed by en bloc mucosectomy, two (3.2 %) by endoscopic submucosal dissection (ESD) and two (3.2 %) by a hybrid technique. The recurrence rate was 25.8 %. Three patients needed complementary surgical treatment and the clinical success of endoscopic treatment was 95.1 %. CONCLUSION: recurrence rate after endoscopic resection of large colorectal lesions was 25.8 % and surgical complementation rate due to failure in the endoscopic treatment of recurrence was 4.8 %.

Adult blaschkolinear acquired inflammatory skin eruption (BLAISE) with simultaneous features of lichen striatus and blaschkitis.

Blaschkitis and lichen striatus are generally distinguished in the literature by the age of onset, lesion distribution, and histopathology. However, there is currently no clear consensus among authors about whether to consider blaschkitis and lichen striatus different clinical entities or a spectrum ofthe same disease. We present a case of adult BLAISE with features of both lichen striatus and blaschkitis, which seems to support the theory that these clinical entities may in fact represent a spectrum of the same pathological process.

Hidradenitis Suppurativa in Children Treated with Finasteride-A Case Series.

BACKGROUND: Hidradenitis suppurativa (HS) is rare in childhood, with only 2% of cases in patients younger than 11 years. It is a chronic, recurrent, debilitating condition for which no universally effective treatment has been developed. We present five cases of children with HS diagnosed between the ages of 6 and 11 years. METHODS: Patients were treated with oral finasteride 1 to 5 mg/day. All had entered puberty at the time of treatment initiation. All had normal laboratory results before starting treatment. The maximum duration of treatment was 24 months. RESULTS: Four patients were female. Two were overweight. Three had been previously treated with oral antibiotics, and two of these with oral isotretinoin, with partial or no improvement. Overall improvement of the disease was observed in all patients, with a reduction of the frequency and intensity of the flares. No adverse effects were observed or reported during treatment. CONCLUSION: Treatment of HS can be challenging. The options available include antimicrobials, immunosuppressants, hormonal therapies, lasers, and surgery. The authors report the largest series of children with HS treated with finasteride. The results support the use of finasteride as monotherapy for the treatment of this disease in children. Further studies are necessary to fully understand the role of this drug in the management of this disease.

Infantile myofibromatosis - a clinical and pathological diagnostic challenge.

Infantile myofibromatosis is a rare disorder of fibroblastic/myofibroblastic proliferation and represents the most frequent type of mesenchymal tumor in the neonatal period and primary infancy.Three clinical types have been described: solitary, multicentric, and generalized (with visceral involvement). A correct characterization of the histopathology is essential to diagnose these neoplasias in early infancy. We present a case of multicentric infantile myofibromatosis with regression over time.

Nasolabial flap - alternative uses for a classic but versatile technique.

The nasolabial flap is one of the most ancient techniques used in orofacial surgery. The authors report two cases of patients with skin cancer treated surgically with variations of the classic nasolabial flap by transposition (bilateral and folded) that highlight the broad applicability of this technique.

Primary vulvar Paget disease - the importance of clinical suspicion.

Extramammary Paget disease of the vulva is a rare condition that accounts for only 1-2% of vulvar malignancies and represents a frequent cause of misdiagnosis. It is most commonly seen in postmenopausal women. Clinically it is similar to Paget disease of the breast, appearing as red, well-demarcated eczematoid lesions, with slightly raised edges. A high degree of clinical suspicion is very important when evaluating these lesions in order to avoid misdiagnosis and delay of effective treatment. We present a case of vulvar Paget disease treated with vulvectomy.

Annular elastolytic giant cell granuloma: a "visible" diagnosis.

Annular elastolytic giant cell granuloma (AEGCG) is a rare granulomatous skin disease of undetermined cause, characterized by annular plaques with raised erythematous borders in sun-exposed skin. The typical histologic features are dermal infiltration by multinucleated giant cells, elastin degeneration, and elastophagocytosis. The authors describe a clinical case of AEGCG, which exhibited an excellent response to hydroxycloroquine.

Plasmablastic lymphoma: an atypical cutaneous presentation of a rare entity.

Plasmablastic lymphoma is a very rare B-cell lymphoma typically associated with immunosuppression: It occurs primarily in the oral cavity, although some cases were reported in other organs and tissues.To date, only 10 cases of primary cutaneous plasmablastic lymphoma have been described. Clinically, primary cutaneous plasmablastic lymphoma presents as non-specific cutaneous lesions (purple nodules, erythematous infiltrated plaques). In previously described cases, as in this case, histology and immunohistochemistry are required to make the diagnosis. Owing to the rarity of this entity, there is no established therapy, which makes its management an individualized, patient-based decision.

Unravelling the Key Driving Forces of the Spin Transition in π-Dimers of Spiro-biphenalenyl-Based Radicals.

Spiro-biphenalenyl (SBP) boron radicals constitute an important family of molecules for the preparation of functional organic materials. The building blocks of several SBP-based crystals are π-dimers of these radicals, in which two phenalenyl (PLY) rings face each other and the other two PLYs point away from the superimposed PLYs. The dimers of ethyl-SBP and butyl-SBP undergo a spin transition between a diamagnetic and a paramagnetic state upon heating, while other dimers exhibit paramagnetism at all temperatures. Here, we present a computational study aimed at establishing the driving forces of the spin-transition undergone by ethyl-SBP at ∼140 K. The ground state of the π-dimers below 140 K is a singlet state in which the SBP unpaired electrons are partially localized in the superimposed PLYs. Above 140 K, the unpaired electrons are localized in the nonsuperimposed PLYs. These high-temperature structures are exclusively governed by the ground triplet state because the open-shell singlet with the unpaired electrons localized in the nonsuperimposed PLYs does not feature any minimum in the potential energy surface of the system. Furthermore, we show that the electrostatic component of the interaction energy between SBP radicals in the π-dimers is more attractive in the triplet than in the singlet, thereby partially counteracting the bonding and dispersion components, which favor the singlet. This electrostatic stabilization of the triplet state is a key driving force of the spin transition of ethyl-SBP and a key factor explaining the paramagnetic response of the π-dimers of other SBP-based crystals.

A New Conformation With an Extraordinarily Long, 3.04†ŠTwo-Electron, Six-Center Bond Observed for the π-[TCNE]2 (2-) Dimer in [NMe4 ]2 [TCNE]2 (TCNE=Tetracyanoethylene).

Invited for the cover of this issue are the groups of Joel S. Miller at the University of Utah and Juan J. Novoa at the University of Barcelona. The image depicts a visualization of the energy difference between the new 2e(-) /6c and the established 2e(-) /4c bond for C2 and D2h conformations, respectively, for π-[TCNE]2 (2-) . Read the full text of the article at 10.1002/chem.201501963.

A New Conformation With an Extraordinarily Long, 3.04†ŠTwo-Electron, Six-Center Bond Observed for the π-[TCNE]2 (2-) Dimer in [NMe4 ]2 [TCNE]2 (TCNE=Tetracyanoethylene).

[NMe4 ]2 [TCNE]2 (TCNE=tetracyanoethenide) formed from the reaction of TCNE and (NMe4 )CN in MeCN has νCN IR absorptions at 2195, 2191, 2172, and 2156 cm(-1) and a νCC absorption at 1383 cm(-1) that are characteristic of reduced TCNE. The TCNEs have an average central CC distance of 1.423 Šthat is also characteristic of reduced TCNE. The reduced TCNE forms a previously unknown non-eclipsed, centrosymmetric π-[TCNE]2 (2-) dimer with nominal C2 symmetry, 12 sub van der Waals interatomic contacts <3.3 Å, a central intradimer separation of 3.039(3) Å, and comparable intradimer C⋅⋅⋅N distances of 3.050(3) and 2.984(3) Å. The two pairs of central C⋅⋅⋅C atoms form a ∢C-C⋅⋅⋅C-C of 112.6° that is substantially greater than the 0° observed for the eclipsed D2h π-[TCNE]2 (2-) dimer possessing a two-electron, four-center (2e(-) /4c) bond with two C⋅⋅⋅C components from a molecular orbital (MO) analysis. A MO study combining CAS(2,2)/MRMP2/cc-pVTZ and atoms-in-molecules (AIM) calculations indicates that the non-eclipsed, C2 π-[TCNE]2 (2-) dimer exhibits a new type of a long, intradimer bond involving one strong C⋅⋅⋅C and two weak C⋅⋅⋅N components, that is, a 2e(-) /6c bond. The C2 π-[TCNE]2 (2-) conformer has a singlet, diamagnetic ground state with a thermally populated triplet excited state with J/kB =1000 K (700 cm(-1) ; 86.8 meV; 2.00 kcal mol(-1) ; H=-2 JSa ⋅Sb ); at the CAS(2,2)/MBMP2 level the triplet is computed to be 9.0 kcal mol(-1) higher in energy than the closed-shell singlet ground state. The results from CAS(2,2)/NEVPT2/cc-pVTZ calculations indicate that the C2 and D2h conformers have two different local metastable minima with the C2 conformer being 1.3 kcal mol(-1) less stable. The different natures of the C2 and D2h conformers are also noted from the results of valence bond (VB) qualitative diagram that shows a 10e(-) /6c bond with one C⋅⋅⋅C and two C⋅⋅⋅N bonding components for the C2 conformer as compared to the 6e(-) /4c bond for the D2h conformer with two C⋅⋅⋅C bonding components.

Unusual electronic properties and transmission in hexagonal SiB monolayers.

After the success of graphene, several two-dimensional (2D) layers have been proposed and investigated both theoretically and experimentally in order to evaluate their structural stability and possible applications of these unusual materials in electronics. Except for graphene, only silicon and germanium were predicted to form semi-metallic honeycomb monolayers, while most of the binary graphene-like compounds are all semiconductors. These predictions have been corroborated for several 2D structures experimentally synthesized. Considering the possibility of finding other candidates in this realm, exhibiting exceptional electron mobility, we have explored low-dimensional silicon-boron compounds containing planar sp(2)-bonding silicon atoms, through first-principles density-functional theory calculations. We have demonstrated that the so-called h-SiB sheet, which is a structural analogue of 2D honeycomb binary compounds, exhibits good structural stability, compared to the structure of silicene, for example, and predicted that this structure is also able to roll up into thermally stable single-walled silicon-boron nanotubes. The h-SiB sheet exhibits a delocalized charge density like in graphene, but the partially filled π band and two highest occupied σ bands are above the Fermi level, leading to the metallic behaviour of this SiB sheet. In this sense, we perform first-principles electron transport calculations, based on the nonequilibrium Green's function formalism, which has demonstrated that h-SiB exhibits higher transmission around the Fermi energy than the transmission in graphene. Our results indicate the unusual conductivity of this new material and open up new possibilities for the realization of metallic graphene-like systems for electronic transport in low dimensions.

Diradicals acting through diamagnetic phenylene vinylene bridges: Raman spectroscopy as a probe to characterize spin delocalization.

We present a complete Raman spectroscopic study in two structurally well-defined diradical species of different lengths incorporating oligo p-phenylene vinylene bridges between two polychlorinated triphenylmethyl radical units, a disposition that allows sizeable conjugation between the two radicals through and with the bridge. The spectroscopic data are interpreted and supported by quantum chemical calculations. We focus the attention on the Raman frequency changes, interpretable in terms of: (i) bridge length (conjugation length); (ii) bridge conformational structure; and (iii) electronic coupling between the terminal radical units with the bridge and through the bridge, which could delineate through-bond spin polarization, or spin delocalization. These items are addressed by using the "oligomer approach" in conjunction with pressure and temperature dependent Raman spectroscopic data. In summary, we have attempted to translate the well-known strategy to study the electron (charge) structure of π-conjugated molecules by Raman spectroscopy to the case of electron (spin) interactions via the spin delocalization mechanism.