Multivesicular hepatic human hydatid cyst from Iran: First genotyping‐based confirmation

Cystic echinococcosis is one of the most important zoonotic parasitic diseases caused by the tapeworm Echinococcus granulosus. To date, the genotype of multivesicular CE has not been identified. In this regard, the genotyping of multivesicular types of CE could help clinicians understand and manage the disease effectively.     

Sulfated zirconium oxide-decorated magnetite KCC-1 as a durable and recyclable adsorbent for the efficient removal of asphaltene from crude oil

Sulfated zirconium oxide (ZrO₂/SO₄²⁻) as a highly durable acidic reagent was immobilized on magnetite KCC-1 nanoparticles (Fe₃O₄@SiO₂/KCC-1@ZrO₂/SO₄²⁻ NPs), and the resulting hybrid was used as a highly efficient recyclable adsorbent for the adsorption and removal of asphaltene from crude oil. The presence of ZrO₂/SO₄²⁻ groups not only promotes the adsorption capacity, but also helps recycle the adsorbents without any significant efficiency loss arising from its high chemical resistance. The results showed an obvious synergistic effect between the magnetic core (Fe₃O₄ NPs), fibrous silica (KCC-1) and the sulfated zirconium oxide groups with high correlation for asphaltene adsorption. The effective parameters in asphaltene adsorption, including initial asphaltene concentration, catalyst concentration and temperature, were investigated. Maximum adsorption occurred in the presence of 0.7 g L⁻¹ of the adsorbent, at a concentration of 2000 mg L⁻¹ of asphaltene. The asphaltene adsorption by NPs follows a quasi-second order adsorption kinetics. Asphaltene adsorption kinetics were studied by Langmuir, Freundlich, and Temkin isotherms. The prominent advantage of the adsorbent is its ability to be recovered after each adsorption by acid treatment, so that no significant reduction in adsorbent adsorption activity was observed, which can be directly attributed to the presence of ZrO₂/SO₄²⁻ groups in the hybrid.

A new, efficient and recyclable hybrid based on immobilized sulfated zirconium oxide on magnetite fibrous silica (KCC-1) has been developed and utilized for the efficient adsorption and removal of asphaltene from crude oil.     

Effect of interfacial defects on the electronic properties of MoS2 based lateral T–H heterophase junctions

The coexistence of semiconducting (2H) and metallic (1T) phases of MoS₂ monolayers has further pushed their strong potential for applications in the next generation of electronic devices based on two-dimensional lateral heterojunctions. Structural defects have considerable effects on the properties of these 2D devices. In particular, the interfaces of two phases are often imperfect and may contain numerous vacancies created by phase engineering techniques, e.g. under an electron beam. Here, the transport behaviors of the heterojunctions with the existence of point defects are explored by means of first-principles calculations and non-equilibrium Green''s function approach. While vacancies in semiconducting MoS₂ act as scattering centers, their presence at the interface improves the flow of the charge carriers. In the case of V_Mo, the current has been increased by two orders of magnitude in comparison to the perfect device. The enhancement of transmission was explained by changes in the electronic densities at the T–H interface, which open new transport channels for electron conduction.

Our systematic study shows significant improvement in transport properties of MoS₂-based lateral T–H heterophase junctions when interfacial defects are present.

Among the developing family of two-dimensional (2D) materials, transition metal dichalcogenides (TMDs) provide some of the most diverse electronic properties including acting as topological insulators, semiconductors, (semi)metals and superconductors.^1–3 Noticeably, such a difference in the electronic structure of TMDs correlates with their structural configurations, called phases.⁴ Monolayers of MoS₂ in the H-phase, with trigonal prismatic coordination of metal atoms, is a semiconducting material,^5,6 while T-phase with octahedral coordination shows metallic character. The H-phase monolayer is reported to be a promising material for field-effect transistors (FETs) with small-scale channel lengths and negligible current leakage.^5,6Recent experiments have already shown controlled transitions from one phase to another via external stimuli such as electron beam,⁷ ion intercalation,⁸ or laser irradiation.⁹ These phase-engineered 2D materials with minimum variations in atomic structure and uniform stoichiometry not only demonstrate rich physical behavior but also open up new avenues for the design of electronic devices. The fabrication of lateral metallic/semiconducting heterostructures has been suggested as a practical method to minimize the contact resistance at the interface between 2D semiconductors and metal electrodes. In particular, the formation of covalent bonds between the two phases can introduce paths for carriers to travel across the interfaces, thus, the Schottky barrier and contact resistance are reduced.^10–13 It has also been demonstrated that 1T-phase engineered electrodes in MoS₂ based electronic devices would generate ohmic contacts and, as a result, improve electrical characteristics.^12,14Apart from intrinsic defects, the local phase transitions induced by electron beam irradiation may give rise to the formation of point defects, in particular at the interface of the two phases.^15–22 Defects can also be intentionally introduced during the post-growth stage via ion bombardment, plasma treatment, vacuum annealing, or chemical etching.^15–22 Indeed, theoretical and experimental results showed that the presence of sulfur vacancies can decrease the energy difference between the H and T phases and eventually stabilize the 1T phase in MoS₂ monolayer.^23,24 The presence of point defects in semiconducting MoS₂ monolayers leads to the observation of the localized states in their electronic structure, which act as short-ranged scattering centers for charge carriers.^25–28 Hence, defects were found to deteriorate the mobility of the fabricated devices.^29–31 It was also shown that sulfur line vacancies in MoS₂ can behave like pseudo-ballistic wire for electron transport.³²So far, several theoretical studies have reported the transport properties of phase-engineered devices based on TMDs monolayers including MoS₂ based lateral junctions.^{11,12,33–35,35–37} In most of these studies, however, it is assumed that two phases have a perfect crystalline structure and connected via an atomically sharp and defect-free interface.Here, transport properties of devices based on MLs MoS₂, containing various point vacancies and antisites at the interface between metallic and semiconducting phases, are the subject of the present study. Our systematic investigations show significant improvements in the current, as molybdenum vacancy and vacancy complexes are created at the interfaces of two phases. These findings render defect engineering as an efficient route to further improve the performance of the devices based on the lateral heterojunctions formed from TMDs.     

One‐step and sequential SARSCOV‐2 polymerase chain reaction tests would not work every time

IntroductionRT‐PCR is widely used as a diagnostic test for the detection of SARS‐CoV‐2. In this study, we aim to describe the clinical utility of serial PCR testing in the final detection of COVID‐19.MethodWe collected multiple nasopharyngeal swab samples from patients who had negative RT‐PCR test on the first day after hospitalization. RT‐PCR tests were performed on the second day for all patients with initial negative result. For the patients with secondary negative results on day 2, tertiary RT‐PCR tests were performed on day 3 after hospitalization.ResultAmong 68 patients with initial negative test results, at the end of follow‐up, the mortality number was 20 (29.4%). About 33.8% of patients had subsequent positive PCR test results for the second time and 17.4% of the patients who performed third PCR test had positive result.ConclusionBased on this study, serial RT‐PCR testing is unlikely to yield additional information.