Search

In the past decade, intensive studies on monolayer MoS2-based phototransistors have been carried out to achieve further enhanced optoelectronic characteristics. However, the intrinsic optoelectronic characteristics of monolayer MoS2 have still not been explored until now because of unintended interferences, such as multiple reflections of incident light originating from commonly used opaque substrates. This leads to overestimated photoresponsive characteristics inevitably due to the enhanced photogating and photoconductive effects. Here, we reveal the intrinsic photoresponsive characteristics of monolayer MoS2, including its internal responsivity and quantum efficiency, in fully transparent monolayer MoS2 phototransistors employing a van der Waals heterostructure. Interestingly, as opposed to the previous reports, the internal photoresponsive characteristics do not significantly depend on the wavelength of the incident light as long as the electron-hole pairs are generated in the same k-space. This study provides a deeper understanding of the photoresponsive characteristics of MoS2 and lays the foundation for two-dimensional materials-based transparent phototransistors.

The demand for large-area, high-quality synthesis of graphene with chemical vapor deposition (CVD) has increased for the realization of next-generation transparent and flexible optoelectronic applications. In conventional CVD processes, various synthesis parameters can strongly affect the quality of the resultant graphene. In particular, surface engineering of a copper catalyst substrate is one of the most promising pathways for achieving high-quality graphene with excellent reproducibility. For this purpose, simple wet chemical etching of a catalyst substrate without toxic fume byproducts or metal ion residues is desired. Here, we suggest a facile method for preparing a pretreated copper catalyst substrate for highly uniform, large-area CVD graphene growth. This pretreatment method involves a wet copper etchant, ammonium persulfate (APS) solution, and gentle ultrasonication (100 W), which do not produce unwanted or toxic fume byproducts during their reaction. Moreover, this approach does not leave metal ion residue on the cleaned copper substrates that serves as residual nucleation sites and leads to multilayer graphene growth. To evaluate the quality of the synthesized monolayer graphene on the cleaned copper catalyst substrates, we used various characterization techniques, such as Raman spectroscopy and sheet resistance, optical transmittance, and FET characterization.

Phyllanthus emblica is widely used in Ayurvedic preparations against multiple disorders and contains various bioactive components. This study aimed to determine the preventive effect of P. emblica on obesity by evaluating the inhibition of adipogenesis and the related regulatory epigenetic mechanisms during 3T3-L1 differentiation. The ethyl acetate fraction of P. emblica (EFPE) effectively inhibited lipid accumulation and triglyceride (TG) production in 3T3-L1 adipocytes. It also inhibited histone acetyltransferase (HAT) activity and regulated Pcaf-specific H3K9 acetylation and the expression of adipogenesis-related genes during adipocyte differentiation. Phenolic compounds were the main components of EFPE, of which gallic acid (GA) exhibited the strongest inhibitory effect on lipid accumulation and TG production. Notably, GA effectively regulated adipogenesis-mediated gene expression through H3K9 acetylation. These findings, along with the experiment results, suggest that EFPE containing GA is a potent agent for preventing obesity by regulating H3K9 acetylation. [ABSTRACT FROM AUTHOR]

Background: During the modified Broström procedure for chronic ankle instability, surgeons often experience cases with insufficiently restored mechanical stability even after anatomical ligament repair. In these cases, longer postoperative immobilization and delayed rehabilitation can be required, and a risk for recurrence of instability may persist. This study aimed to evaluate the clinical usefulness of suture-tape augmentation based on intraoperative stress radiographs during anatomical ligament repair for chronic ankle instability. Methods: Twenty-four patients who underwent additional suture-tape reinforcement because of residual mechanical instability on intraoperative stress radiographs were followed up ≥3 years. Clinical assessment was performed using the Foot and Ankle Outcome Score (FAOS) and Foot and Ankle Ability Measure (FAAM). Changes in mechanical stability were analyzed through periodic stress radiographs, and postural control ability was evaluated with the modified Romberg test. Results: FAOS and FAAM scores improved significantly from preoperative mean 55.1 and 52.4 points to 92.3 and 90.2 points at final follow-up, respectively (P <.001). Talar tilt angle and anterior talar translation improved significantly from preoperative mean 15.8 degrees and 13.6 mm to 2.9 degrees and 4.2 mm, respectively (P <.001). Balance retention time improved significantly from preoperative mean 3.6 to 6.4 seconds (P <.001). Although 9 patients experienced sprain injury after surgery, no patient showed recurrence of mechanical and subjective instability, and 21 patients (87.5%) were able to return to preinjury level of sports activity. Conclusion: Evaluation of residual mechanical instability through intraoperative stress view and additional suture-tape augmentation showed satisfactory clinical outcomes at midterm follow-up. Suture-tape augmentation based on intraoperative stress radiographs seems to be a useful surgical option for patients with insufficiently restored mechanical stability even after anatomical ligament repair. This combined procedure can provide a reliable mechanical stability that can be performed after recognition of residual instability during the index surgery. [ABSTRACT FROM AUTHOR]