Realizing Electronic Synapses by Defect Engineering in Polycrystalline Two-Dimensional MoS for Neuromorphic Computing.

Neuromorphic computing based on two-dimensional transition-metal dichalcogenides (2D TMDs) has attracted significant attention recently due to their extraordinary properties generated by the atomic-thick layered structure. This study presents sulfur-defect-assisted MoS artificial synaptic devices fabricated by a simple sputtering process, followed by a precise sulfur (S) vacancy-engineering process. While the as-sputtered MoS film does not show synaptic behavior, the S vacancy-controlled MoS film exhibits excellent synapse with remarkable nonvolatile memory characteristics such as a high switching ratio (∼10), a large memory window, and long retention time (∼10 s) in addition to synaptic functions such as paired-pulse facilitation (PPF) and long-term potentiation (LTP)/depression (LTD).

Heritability of cognitive abilities and regional brain structures in middle-aged to elderly East Asians.

This study examined the single-nucleotide polymorphism heritability and genetic correlations of cognitive abilities and brain structural measures (regional subcortical volume and cortical thickness) in middle-aged and elderly East Asians (Korean) from the Gwangju Alzheimer's and Related Dementias cohort study. Significant heritability was found in memory function, caudate volume, thickness of the entorhinal cortices, pars opercularis, superior frontal gyri, and transverse temporal gyri. There were 3 significant genetic correlations between (i) the caudate volume and the thickness of the entorhinal cortices, (ii) the thickness of the superior frontal gyri and pars opercularis, and (iii) the thickness of the superior frontal and transverse temporal gyri.

Unusually High Ion Conductivity in Large-Scale Patternable Two-Dimensional MoS Film.

The advancement of ion transport applications will require the development of functional materials with a high ionic conductivity that is stable, scalable, and micro-patternable. We report unusually high ionic conductivity of Li, Na, and K in 2D MoS nanofilm exceeding 1 S/cm, which is more than 2 orders of magnitude higher when compared to that of conventional solid ionic materials. The high ion conductivity of different cations can be explained by the mitigated activation energy percolative ion channels in 2H-MoS, including the 1D ion channel at the grain boundary, as confirmed by modeling and analysis.

Different therapeutic associations of renin-angiotensin system inhibitors with coronavirus disease 2019 compared with usual pneumonia.

Background/aims: Although it is near concluded that renin-angiotensin system inhibitors do not have a harmful effect on coronavirus disease 2019 (COVID-19), there is no report about whether angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) offer any protective role. This study aimed to compare the association of ARBs and ACEIs with COVID-19-related mortality.

Methods: All patients with COVID-19 in Korea between January 19 and April 16, 2020 were enrolled.

Beneficial Effect of Statins in COVID-19-Related Outcomes-Brief Report: A National Population-Based Cohort Study.

Objective: Although statins are widely prescribed lipid-lowering drugs, there are concerns about the safety of their use in the context of coronavirus disease 2019 (COVID-19), since statins increase the expression of ACE2 (angiotensin-converting enzyme 2). This study aimed to disclose the association between statins and 60-day COVID-19 mortality. Approach and Results: All patients hospitalized with laboratory-confirmed COVID-19 were enrolled in this study from January 19 to April 16, 2020, in Korea.

Composition-Tunable Synthesis of Large-Scale MoW S Alloys with Enhanced Photoluminescence.

Alloying two-dimensional transition metal dichalcogenides (2D TMDs) is a promising avenue for band gap engineering. In addition, developing a scalable synthesis process is essential for the practical application of these alloys with tunable band gaps in optoelectronic devices. Here, we report the synthesis of optically uniform and scalable single-layer MoW S alloys by a two-step chemical vapor deposition (CVD) method followed by a laser thinning process.

Publisher Correction: 2D MoS as an efficient protective layer for lithium metal anodes in high-performance Li-S batteries.

In the version of this Article originally published, a technical error in typesetting led to the traces in Fig. 3a being trimmed and made to overlap. The figure has now been corrected with the traces as supplied by the authors; the original and corrected Fig.

2D MoS as an efficient protective layer for lithium metal anodes in high-performance Li-S batteries.

Among the candidates to replace Li-ion batteries, Li-S cells are an attractive option as their energy density is about five times higher (~2,600 Wh kg). The success of Li-S cells depends in large part on the utilization of metallic Li as anode material. Metallic lithium, however, is prone to grow parasitic dendrites and is highly reactive to several electrolytes; moreover, Li-S cells with metallic Li are also susceptible to polysulfides dissolution.

Synthesis of uniform single layer WS for tunable photoluminescence.

Two-dimensional transition metal dichalcogenides (2D TMDs) have gained great interest due to their unique tunable bandgap as a function of the number of layers. Especially, single-layer tungsten disulfides (WS) is a direct band gap semiconductor with a gap of 2.1 eV featuring strong photoluminescence and large exciton binding energy.

Centimeter Scale Patterned Growth of Vertically Stacked Few Layer Only 2D MoS2/WS2 van der Waals Heterostructure.

Two-dimensional (2D) van der Waal (vdW) heterostructures composed of vertically-stacked multiple transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are envisioned to present unprecedented materials properties unobtainable from any other material systems. Conventional fabrications of these hybrid materials have relied on the low-yield manual exfoliation and stacking of individual 2D TMD layers, which remain impractical for scaled-up applications. Attempts to chemically synthesize these materials have been recently pursued, which are presently limited to randomly and scarcely grown 2D layers with uncontrolled layer numbers on very small areas.

Experience of laparoscopic liver resection for various liver diseases.

Backgrounds/aims: We present our experience of laparoscopic liver resection for various liver diseases.

Methods: From April 2008 to August 2012 in Chungnam National University, 68 of 253 liver resections were performed laparoscopically. During the first year, laparoscopy-assisted liver resection was mainly performed and subsequently totally laparoscopic liver resection was the main operative type.

Growth of large-scale and thickness-modulated MoS₂ nanosheets.

Two-dimensional MoS2 is a promising material for next-generation electronic and optoelectronic devices due to its unique electrical and optical properties including the band gap modulation with film thickness. Although MoS2 has shown excellent properties, wafer-scale production with layer control from single to few layers has yet to be demonstrated. The present study explored the large-scale and thickness-modulated growth of atomically thin MoS2 on Si/SiO2 substrates using a two-step sputtering-CVD method.

Valsalva retinopathy following esophagogastroduodenoscopy under propofol sedation: a case report.

We report a case of Valsalva retinopathy associated with esophagogastroduodenoscopy (EGD) under propofol sedation. A 43-year-old woman who had no previous history of systemic or ocular disease presented with a complaint of decreased vision in her left eye, which developed one day after EGD under propofol sedation. According to the referring physician, the patient had experienced multiple sustained Valsalva maneuvers during EGD.